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  • 151.
    Chen, Eric Zhi
    Kristianstad University, School of Engineering.
    Good quasi-cyclic codes derived from irreducible cyclic codes2005In: Proceedings of Optimal Codes and Related Topics (OC2005), 2005, p. 74-81Conference paper (Refereed)
    Abstract [en]

    As a generalization of cyclic codes, quasi-cyclic codes contain many good linear codes. Extensive search is made and lots of good quasi-cyclic codes are obtained from irreducible cyclic codes. A new binary [95, 13, 40] code which improves the lower bound on the minimum distance, is also constructed.

  • 152.
    Chen, Eric Zhi
    Kristianstad University, School of Health and Society, Avdelningen för Design och datavetenskap.
    New binary h-generator quasi-cyclic codes by augmentation and new minimum distance bounds2016In: Designs, Codes and Cryptography, ISSN 0925-1022, E-ISSN 1573-7586, Vol. 80, no 1, p. 1-10Article in journal (Refereed)
    Abstract [en]

    An [n, k, d] code is a binary linear code of block length n, dimension k and minimum Hamming distance d. Since the minimum distance determines the error detection or correction capability, it is desired that d is as large as possible for the given block length n and dimension k. One of the most fundamental problems in coding theory is to construct codes with best possible minimum distances. This problem is very difficult in both theory and practice. During the last decades, it has proved that the class of quasi-cyclic (QC) codes contain many such codes. In this paper, augmentation of binary QC codes is studied. A new augmentation algorithm is presented, and 10 new h-generator QC codes that are better than previously known code have been constructed. Furthermore, Construction X has been applied to obtain another 18 new improved binary linear codes.With the standard construction techniques, a total of 124 new binary linear codes that improve the lower bound on the minimum distance have been obtained.

  • 153.
    Chen, Eric Zhi
    Kristianstad University, School of Engineering.
    New constructions of a family of 2-generator quasi-cyclic two-weight codes and related codes2007In: Proc. of 2007 IEEE Internat. Symp. on Inform. Theory, Piscataway, NJ: IEEE , 2007, p. 2191-2195Conference paper (Refereed)
    Abstract [en]

    Based on cyclic simplex codes, a new construction of a family of two-weight codes is given. These two-weight codes are in a simple 2-generator quasi-cyclic form. Based on this construction, new optimal binary quasi-cyclic [195, 8, 96], [210, 8, 104] and [240, 8, 120] codes, good QC ternary  [195, 6, 126], [208, 6, 135], [221, 6, 144] codes are thus obtained. It was also shown that some codes that meet the Griesmer bound and thus are optimal. Furthermre, binary  self-complementary codes in a 3-generator quasi-cyclic form,  are also constructed.

  • 154.
    Chen, Eric Zhi
    Kristianstad University, School of Health and Society, Avdelningen för Design och datavetenskap.
    New constructions of combinatorial designs and related codes2002In: Proceedings of the 8th International Workshop on Algebraic coding and Combinatorial Theory (ACCT-VIII), 2002, p. 264-267Conference paper (Refereed)
    Abstract [en]

    New constructions of Steiner systems, majority logic decodable codes, and constant weight codes are presented. Comparisons with known results as well as examples are also given.

  • 155.
    Chen, Eric Zhi
    Kristianstad University, School of Health and Society, Avdelningen för Design och datavetenskap.
    New results on binary quasi-cyclic codes2000In: 2000 Ieee International Symposium on Information Theory: Proceedings, IEEE conference proceedings, 2000, p. 197-Conference paper (Refereed)
    Abstract [en]

    Twelve new binary quasi-cyclic codes, which improve the lower bounds on minimum distances for binary linear codes, are presented, and a Web database on best-known binary quasi-cyclic codes is constructed for public access.

  • 156.
    Chen, Eric Zhi
    Kristianstad University, School of Health and Society, Avdelningen för Design och datavetenskap.
    Quasi-cyclic codes derived from cyclic codes2004In: Proceedings of Int. Symp. on Information Theory and its Applications (ISITA2004), Parma, Italy, 2004, p. 162-165Conference paper (Refereed)
  • 157.
    Chen, Eric Zhi
    Linköping university.
    Six new binary quasi-cyclic codes1994In: IEEE Transactions on Information Theory, ISSN 0018-9448, E-ISSN 1557-9654, Vol. 40, no 5, p. 1666-1667Article in journal (Refereed)
    Abstract [en]

    Six new quasi-cyclic codes are presented, which improve thelower bounds on the minimum distance for a binary code. A localexhaustive search is used to find these codes and many other quasi-cycliccodes which attain the lower bounds.

  • 158.
    Chen, Eric Zhi
    et al.
    Kristianstad University, School of Health and Society, Avdelningen för Design och datavetenskap.
    Aydin, Nuh
    USA.
    New databases of linear codes over GF(11) and GF(13)2014In: Proceedings of Karatekin mathematics days 2014: international mathematics symposium, 2014, p. 22-22Conference paper (Refereed)
    Abstract [en]

    One central problem in coding theory is to optimize the parameters of a linear code and construct codes with best possible parameters. There are tables of best-known linear codes over nite elds of sizes up to 9. Recently, there has been a growing interest in codes over GF(11), over GF(13) and other elds of size greater than 9. The main purpose of this work is to present new databases of best-known linear codes over the elds GF(11) and GF(13) together with upper bounds on the minimum distances. To nd good linear codes to establish lower bounds on minimum distances, an iterative heuristic computer search algorithm is employed to construct quasi-twisted (QT) codes over these elds with high minimum distances. A large number of new linear codes have been found, improving previously best-known results. Tables of [pm, m] QT codes over the two elds with best-known minimum distances as well as a table of lower and upper bounds on the minimum distances for linear codes of length up to 150 and dimension up to 6 are presented.

  • 159.
    Chen, Eric Zhi
    et al.
    Kristianstad University, School of Health and Society, Avdelningen för Design och datavetenskap.
    Aydın, Nuh
    USA.
    A database of linear codes over F13 with minimum distance bounds and new quasi-twisted codes from a heuristic search algorithm2015In: Journal of Algebra Combinatorics Discrete Structures and Application, ISSN 2148-838X, Vol. 2, no 1, p. 1-18Article in journal (Refereed)
    Abstract [en]

    Error control codes have been widely used in data communications and storage systems. One centralproblem in coding theory is to optimize the parameters of a linear code and construct codes withbest possible parameters. There are tables of best-known linear codes over finite fields of sizes up to9. Recently, there has been a growing interest in codes over F13 and other fields of size greater than9. The main purpose of this work is to present a database of best-known linear codes over the fieldF13 together with upper bounds on the minimum distances. To find good linear codes to establishlower bounds on minimum distances, an iterative heuristic computer search algorithm is employed toconstruct quasi-twisted (QT) codes over the field F13 with high minimum distances. A large numberof new linear codes have been found, improving previously best-known results. Tables of [pm;m] QTcodes over F13 with best-known minimum distances as well as a table of lower and upper bounds onthe minimum distances for linear codes of length up to 150 and dimension up to 6 are presented.

  • 160.
    Chen, Eric Zhi
    et al.
    Kristianstad University, School of Health and Society, Avdelningen för Design och datavetenskap.
    Nuh, Aydin
    USA.
    New quasi-twisted codes over F11— minimum distance bounds and a new database2015In: Journal of Information and Optimization Sciences, ISSN 0252-2667, E-ISSN 2169-0103, Vol. 36, no 1-2, p. 129-157Article in journal (Refereed)
    Abstract [en]

    One fundamental and challenging problem in coding theory is to optimize the parameters [nk,d] of a linear code over the finite field Fq and construct codes with best possible parameters. There are tables and databases of best-known linear codes over the finite fields of size up to 9 together with upper bounds on the minimum distances. Motivated by recent works on codes over F11, we present a table of best-known linear codes over F11 together with upper bounds on minimum distances. Our table covers the range n ≤ 150 for the length, and 3 ≤ k ≤ 7 for the dimension. To the best of our knowledge, this is the first time such a table is presented in the literature. For the construction of the best-known codes, we employed an iterative heuristic search algorithm to search for new linear codes in the class of quasi-twisted (QT) codes. The search yielded many new codes with better parameters than previously known codes. In many cases, optimal codes are obtained. In addition to presenting a comprehensive table of best-known codes over F11 of dimensions up to 7 with upper bounds on the minimum distances, we also present separate tables for the optimal codes and new QT codes over F11. We hope that this work will be a useful source for further study on codes over F11.

  • 161.
    Chen, Qinqing
    et al.
    Kristianstad University, Faculty of Natural Science.
    Su, Xiao
    Kristianstad University, Faculty of Natural Science.
    Improve Improper Load Distribution with Backpack2018Independent thesis Basic level (degree of Bachelor), 180 HE creditsStudent thesis
    Abstract [en]

    This article focuses on the distribution of backpack pressure on human body. We have noticed two interesting situations: whether the length of different backpack shoulder straps will change the pressure distribution of the backpack on the human body and whether different positions of the backpack load will change the pressure distribution of the backpack on the human body. To find the answer, we designed a backpack pressure detection system to collect data and use engineering software to analyse the data.We got the range that best fits the human body and the healthiest backpack: when the distance from the top of the backpack to the shoulder is about 1/5 of the length of the shoulder and the weight of the backpack is at the bottom of the backpack. At this time, the force of the three parts of the human body (shoulders, back) is the most uniform and relatively minimal. If the user wants to minimize the pressure on the shoulder, the shoulder strap of the backpack should be as short as possible. If the user only wants the pressure on the back to be minimal, the weight in the backpack is closer to the back, which is better for the back.

  • 162.
    Chen, Wende
    et al.
    Academia Sinica and Key State Lab. of Information Security, Graduate School of Academia Sinica, Institute of Systems Science, Beijing.
    Chen, Eric Zhi
    Kristianstad University, School of Health and Society, Avdelningen för Design och datavetenskap.
    Klove, Torleiv
    Department of Informatics, University of Bergen.
    New constructions of disjoint distinct difference sets1998In: Designs, Codes and Cryptography, ISSN 0925-1022, E-ISSN 1573-7586, Vol. 15, no 2, p. 157-165Article in journal (Refereed)
    Abstract [en]

    New constructions of regular disjoint distinct difference sets (DDDS) are presented. In particular,multiplicative and additive DDDS are considered.

  • 163.
    ChenReddy, Suresh Reddy
    et al.
    Kristianstad University College, School of Engineering.
    Mirza, Akbar Ali Baig
    Kristianstad University College, School of Engineering.
    SMS Based Pull Campaign Processing System2007Independent thesis Basic level (degree of Bachelor)Student thesis
    Abstract [en]

    SMS based pull campaign processing system is a new model of directory service provided in mobile infrastructure basically to enable SMS based directory services Mobile directory services is a brand new phenomenon, which hold strong promises to become the best targeting advertising medium delivering new means of services to users with message other than traditional channels (e.g.: print, television, radio and email etc).The main purpose of this system is to bring customers and business organizations closer .It enables SMS based directory services. It not only acts as directory services but also as an advertising medium between the user and the business organizations.

  • 164.
    Christoffersson, Anna
    Kristianstad University, School of Education and Environment.
    Markförändringar kring Perstorpsbäcken och dess påverkan på vattendragets ekologi.2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 165.
    Cifuentes de Gramajo, Luisa
    Kristianstad University, School of Education and Environment.
    Nejayote produced at household level by Mayan women in Guatemala: is it a threat to aquatic ecosystems or a resource for food security?2011Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The aim of this study was to find out if nejayote produced at household level in Guatemala represents a threat to aquatic ecosystems and, if so, propose sustainable processing, reuse and disposal methods. First, all aspects related to nejayote production were explored. This study presents combined results from literature study on corn consumption and Guatemalan demography, a survey to Guatemalan women of all ethnical groups, nixtamalization replica and solids removal experiments and laboratory analysis. Findings indicate that the source of nejayote are approximate 600 000 tones of corn nixtamalized yearly by Mayan women from the rural areas of Guatemala to prepare tortillas for a population of about 5 000 000. From this activity approximately 300 000 tones of concentrated nejayote are produced and 800 000 tones of water are polluted yearly. Approximate 63% of these volumes are discharged into water ecosystems without treatment due to lack of knowledge of its potential negative impact or reuse properties. The study was done on nejayote produced at national level, but the isolation of the Mayan population within less than 20% of the national territory, suggests higher punctuality of nejayote discharges. Chemical and physical analyses made to samples from the nixtamalization replica confirmed its similarity to industrial nejayote, which has proven to be highly pollutant due to high content of organic matter from corn grain pericarp and germ. Concentrations ranges from 200 to 300 ppm of nitrogen, 160 to 190 ppm of phosphorus and 25 000 to 28 000 ppm of organic matter make it a potential fertilizer or soil conditioner. Studies indicate that it can be safely reused as supplementary food for chickens and pigs, to prepare additional corn based foods for humans or it could be safely discharged into ponds, wetlands or pits to minimize any environmental impact. Although findings point to nejayote as a potential aquatic ecosystem pollutant, this depends on the capacity of the specific recipient aquatic ecosystem to adsorb and process the nutrients and on the volumes and concentration of nutrients of the nejayote discharged that might vary from household to household. However, the nutrient rich nejayote can be seen as a potential resource, instead of a pollutant, to improve the nutritional, social and economical conditions of the Mayan populations. Specially women, an isolated segment of society that lacks opportunities and who, according to findings of this study, start processing corn into tortillas from early childhood and continue throughout all their lifetime without any benefit on return.

  • 166. Clausen, P.
    et al.
    Elmberg, Johan
    Kristianstad University, School of Education and Environment.
    Fox, A.
    Heldbjerg, H.
    Lindström, Å.
    Pöysä, Hannu
    Mallard declines in Western Europe: evidence of true population declines or just short-stopping in milder winters?2009In: Abstracts, 2nd Pan-European Duck Symposium, 2009, p. 49-Conference paper (Refereed)
  • 167.
    Collin, Betty
    Kristianstad University, School of Education and Environment.
    Characterization and persistence of potential human pathogenic vibrios in aquatic environments2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Vibrio spp., natural inhabitants of aquatic environments, are one of the most common causes of bacterial gastroenteritis in the world, being spread to humans via the ingestion of seafood, contaminated drinking water or exposure to seawater. The majority of Vibrio spp. are avirulent, but certain strains may sporadically be human pathogenic. Vibrio cholerae may cause cholera and fatal wound infections, Vibrio parahaemolyticus may cause gastroenteritis and Vibrio vulnificus may cause wound infections and sepsis. To expand current knowledge of the occurrence, ecological niche and persistence of potential human pathogenic Vibrio spp. in aquatic environments, occurrence and laboratory studies were performed. The seasonal variation of Vibrio spp. in clams and mussels from Mozambique and Sweden were studied, with isolated strains characterized and compared with those isolated from water samples collected in India. Results showed that the numbers of Vibrio spp. in Mozambican clams peaked during the warmer rainy season and that the dominating species was V. parahaemolyticus. Biochemical fingerprinting and virulence screened by PCR revealed a high similarity among strains from the different aquatic environments. However, isolate functional hemolytic analyses and antibiotic resistance patterns differed between strains; Swedish and Indian strains were less sensitive to the tested antibiotics and had a lower hemolytic capacity than those from Mozambique. Molecular analysis of bacterial DNA from Swedish mussels showed the presence of the three Vibrio spp. most commonly linked with human illness, as well as their associated virulence genes. The strains isolated from marine and clinical environments were equally and highly harmful to the tested eukaryotic cells. The persistence of clinical V. cholerae in aquatic environments was investigated in vivo. Strains were exposed to mussels, with bacterial uptake and elimination then examined. The mussels were able to avoid the most potent strain by complete closure of shells. The less potent strain was accumulated in mussel tissue in low levels and one marine control strain to a higher degree. Mussels eliminated the pathogenic strain less efficiently than they did the marine strain. One clinical and one marine strain were then exposed to 4°C for 21 days, with the temperature then increased to 20°C. The clinical strain was more prone to lose culturability than the marine strain at 4°C, the former performed significantly better in regaining culturability after the temperature up-shift. Subsequently, the persistence of the clinical strain in natural bottom sediment, incubating as above, was studied and results showed a similar decrease in culturable numbers in the sediment as in the water. As the clinical V. cholerae strains did not carry any of the standard set of virulence genes, the ability to change from non-culturable to culturable may be of great importance to strain pathogenicity. The results also show that natural bottom sediment may be a potential reservoir of human pathogenic Vibrio spp.

  • 168.
    Collin, Betty
    et al.
    Kristianstad University, School of Education and Environment.
    Hernroth, Bodil
    Kristianstad University, School of Health and Society.
    Rehnstam-Holm, Ann-Sofi
    Kristianstad University, School of Education and Environment.
    The importance of marine sediments as a reservoir for human pathogenic Vibrio cholerae in cold water conditionsArticle in journal (Refereed)
  • 169.
    Collin, Betty
    et al.
    Kristianstad University, School of Education and Environment.
    Rehnstam-Holm, Ann-Sofi
    Kristianstad University, School of Education and Environment.
    Occurrence and potential pathogenesis of Vibrio cholerae, Vibrio parahaemolyticus and Vibrio vulnificus on the South Coast of Sweden2011In: FEMS Microbiology Ecology, ISSN 0168-6496, E-ISSN 1574-6941, Vol. 78, no 2, p. 306-313Article in journal (Refereed)
    Abstract [en]

    During the summer of 2006, several wound infections - of which three were fatal caused by Vibrio cholerae were reported from patients who had been exposed to water from the Baltic Sea. Before these reports, we initiated a sampling project investigating the occurrence of potential human pathogenic V. cholerae, Vibrio vulnificus and Vibrio parahaemolyticus in The Sound between Sweden and Denmark. The Blue mussel (Mytilus edulis) was used as an indicator to follow the occurrence of vibrios over time. Molecular analyses showed high frequencies of the most potent human pathogenic Vibrio spp.; 53% of mussel samples were positive for V. cholerae (although none were positive for the cholera toxin gene), 63% for V. vulnificus and 79% for V. parahaemolyticus (of which 47% were tdh(+) and/or trh(+)). Viable vibrios were also isolated from the mussel meat and screened for virulence by PCR. The mortality of eukaryotic cells when exposed to bacteria was tested in vivo, with results showing that the Vibrio strains, independent of species and origin, were harmful to the cells. Despite severe infections and several deaths, no report on potential human pathogenic vibrios in this area had been published before this study.

  • 170.
    Collin, Betty
    et al.
    Kristianstad University, School of Education and Environment, Avdelningen för Naturvetenskap.
    Rehnstam-Holm, Ann-Sofi
    Kristianstad University, School of Education and Environment, Avdelningen för Naturvetenskap.
    Ehn Börjesson, Stina-Mina
    Kristianstad University, School of Education and Environment, Avdelningen för Naturvetenskap.
    Mussagy, Aidate
    Department of Biological Sciences, Eduardo Mondlane University, Maputo, Mozambique.
    Hernroth, Bodil
    Kristianstad University, School of Education and Environment, Avdelningen för Naturvetenskap.
    Characteristics of potentially pathogenic vibrios from subtropical Mozambique compared with isolates from tropical India and boreal Sweden2013In: FEMS Microbiology Ecology, ISSN 0168-6496, E-ISSN 1574-6941, Vol. 83, no 2, p. 255-264Article in journal (Refereed)
    Abstract [en]

    Reported outbreaks of Vibrio parahaemolyticus have increased worldwide, particularly in regions of high seafood consumption. In Mozambique, seafood constitutes an important food resource and diarrheal diseases are common among its inhabitants. Edible clams were collected in Maputo Bay during both the dry and rainy seasons, with the results showing the number of viable counts of vibrios in clams to peak during the latter. Vibrio parahaemolyticus was the predominant species identified among the isolated strains. Although only one of 109 total strains carried the tdh virulence gene, 69% of isolates showed evidence of hemolytic capacity when subjected to a functional test. Similar virulence patterns and biochemical properties were found in strains isolated from Indian and Swedish marine waters. Antibiotic resistance was, however, more pronounced in strains isolated from these latter two environments.

  • 171.
    Collin, Betty
    et al.
    Kristianstad University, Department of Mathematics and Science.
    Rehnstam-Holm, Ann-Sofi
    Kristianstad University, Department of Mathematics and Science.
    Hernroth, Bodil
    he Royal Swedish Academy of Sciences, Kristineberg, Fiskebäckskil.
    Faecal contaminants in edible bivalves from Maputo Bay, Mozambique: seasonal distribution, pathogenesis and antibiotic resistance2008In: Open Nutrition Journal, ISSN 1874-2882, Vol. 2, p. 86-93Article in journal (Refereed)
    Abstract [en]

    In Maputo, Mozambique marine bivalves considerably contribute to the diet of the population. This study aimed to investigate seasonal distribution of Escherichia coli and Salmonella in clams from Maputo Bay, and examine their pathogenesis and antibiotic-resistant patterns. Standard multiple tube method revealed that the concentration of coliforms in all samples exceeded the limit for direct consumption, according to EU standards. Thirty-eight percent of the samples contained >60,000 MPN per 100 gram flesh. The occurrence of E. coli did not differ significantly due to season, while Salmonella was present in 100% of the samples during the rainy period and only in 30% during the dry. Multiplex polymerase chain reaction showed that 45% of E. coli isolates were positive for the virulent indicator gene fimA. The Salmonella isolates were identified as S. enterica serovar Typhimurium. Among other isolated coliformic Enterobacteriaceae, Shigella sp. (specie), which in low doses can cause severe gastrointestinal infections, was identified. Antimicrobial susceptibility, recorded by the disk diffusion method, showed resistance to the most commonly used antibiotics. This high levels of faecal contaminants in the clams points out the need for risk assessment and sanitary improvements.

  • 172.
    Collin, Betty
    et al.
    Kristianstad University, School of Education and Environment.
    Rehnstam-Holm, Ann-Sofi
    Kristianstad University, School of Education and Environment.
    Lindmark, Barbro
    Department of Molecular Biology, Umeå University.
    Pal, Amit
    National Institute of Cholera and Enteric Diseases, Kolkata, India.
    Wai, Sun N.
    Department of Molecular Biology, Umeå University.
    Hernroth, Bodil
    Kristianstad University, School of Health and Society.
    The origin of Vibrio cholerae influences uptake and persistence in the blue mussel Mytilus edulis2012In: Journal of Shellfish Research, ISSN 0730-8000, E-ISSN 1943-6319, Vol. 31, no 1, p. 87-92Article in journal (Refereed)
    Abstract [en]

    Vibrio cholerae may cause diarrheal diseases and wound infections, both of which have the potential to be fatal. Transmission to humans is often linked to consumption of contaminated shellfish/drinking water or dermal exposure to water (e.g. when swimming). In this study, we investigated whether different isolates of Vibrio cholerae differ in terms of accumulation, persistence, and viability when encountering blue mussels (Mytilus edulis). Mussel uptake and elimination of three different V. cholerae strains were compared: one fatal clinical non-O1/O139 isolate, one highly potent El Tor biotype, and one marine strain isolated from blue mussels. The results showed that the uptake of the marine strain was significantly higher than the clinical strain, but the elimination process of the marine strain was also more efficient. The El Tor strain was not at all ingested by the mussels. In addition, the survival of bacteria when incubated together with M. edulis hemocytes was tested in vitro. The viability of clinical strains was unaffected by the presence of hemocytes, and the marine strains were even more resistant and able to multiply. We conclude that the highly virulent El Tor biotype was not taken up by the mussels and could thereby escape the mussels' elimination process. The potentially fatal non-O1/O139 V. cholerae strain may accumulate in low numbers, but could be very persistent in mussels.

  • 173.
    Comuni, Federica
    Kristianstad University, Faculty of Natural Science.
    A natural language processing solution to probable Alzheimer’s disease detection in conversation transcripts2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This study proposes an accuracy comparison of two of the best performing machine learning algorithms in natural language processing, the Bayesian Network and the Long Short-Term Memory (LSTM) Recurrent Neural Network, in detecting Alzheimer’s disease symptoms in conversation transcripts. Because of the current global rise of life expectancy, the number of seniors affected by Alzheimer’s disease worldwide is increasing each year. Early detection is important to ensure that affected seniors take measures to relieve symptoms when possible or prepare plans before further cognitive decline occurs. Literature shows that natural language processing can be a valid tool for early diagnosis of the disease. This study found that mild dementia and possible Alzheimer’s can be detected in conversation transcripts with promising results, and that the LSTM is particularly accurate in said detection, reaching an accuracy of 86.5% on the chosen dataset. The Bayesian Network classified with an accuracy of 72.1%. The study confirms the effectiveness of a natural language processing approach to detecting Alzheimer’s disease.

  • 174. Cousins, Sara
    et al.
    Dahlström, Anna
    Emanuelsson, Urban
    Kristianstad University College, School of Teacher Education.
    Eriksson, Ove
    Henningsson, Silvia
    Lennartsson, Tommy
    Lindborg, Regina
    Persson, Inger
    Sjödin, N. Erik
    Stenseke, Marie
    Svensson, Roger
    I nattviolens hage2008In: Olsson, R. (red), Mångfaldsmarker: naturbetesmarker - en värdefull resurs, Uppsala: Centrum för biologisk mångfald , 2008, p. 9-28Chapter in book (Other academic)
    Abstract [sv]

    I en svensk naturbetesmark kan man hitta över 40 växtarter inom en enda kvadratmeter. Det är världsrekord. En stor del av de arter som finns i betesmarkerna förekommer inte i andra naturtyper. Idag återstår inte mer än en tiondel av den areal naturbetesmarker som fanns i Sverige för drygt 100 år sedan. Igenväxningen hotar inte bara en lång rad arter. Också stora kulturhistoriska värden och vårt vackra, variationsrika odlingslandskap står på spel. Fortsatt hävd förutsätter att det finns en levande landsbygd med bärkraftiga jordbruksföretag.

  • 175. Czarnezki, Jason J
    et al.
    Elmberg, Johan
    Kristianstad University, School of Education and Environment, Avdelningen för Naturvetenskap. Kristianstad University, Research environment Man & Biosphere Health (MABH).
    Tuvendal, Magnus
    Benefits from nature are not a private thing2016In: EarthDesk, Vol. Oct 19Article in journal (Other (popular science, discussion, etc.))
  • 176.
    Czernekova, Michaela
    et al.
    Kristianstad University, School of Education and Environment, Avdelningen för Naturvetenskap. Kristianstad University, Research environment Man & Biosphere Health (MABH). Charles University, Prague.
    Janelt, Kamil
    Polen.
    Jönsson, K. Ingemar
    Kristianstad University, Research environment Man & Biosphere Health (MABH). Kristianstad University, School of Education and Environment, Avdelningen för Naturvetenskap.
    Chajec, Łukasz
    Polen.
    Student, Sebastian
    Polen.
    Poprawa, Izabela
    Polen.
    Ultrastructure and 3D reconstruction of the tun in Richtersius coronifer (Richters, 1903)2016Conference paper (Refereed)
    Abstract [en]

    Anhydrobiosis is one of the types of cryptobiosis that is caused by lack of water (desiccation). Formation of a tun seems to be the most important morphological adaptation for entering anhydrobiotic state. During this process the tardigrade body undergo anterior-posterior contraction that causes relocation of some organs such as the pharyngeal bulb. The tun wall of Richtersius coronifer (Eutardigrada,  Macrobiotidae) was composed of multilayered cuticle and epidermis. The epidermis consisted of the single squamous epithelium whose cells were shrunken whereas  the cuticle was composed of epi-, intra- and procuticle, flocculent coat and trilaminate layer. The storage cells of desiccated specimens filled up free inner space and surrounded the internal organs (ovary, digestive system) that were contracted. All cells of the body underwent shrinking and their metabolism was arrested. The cytoplasm of all cells was electron dense but the basic morphology of cells and organelles did not differ between active and anhydrobiotic animals. The structure and the ultrastructure of the desiccated Richtersius coronifer have been described with light and confocal microscopy as well as transmission and scanning electron microscopy. 3D reconstruction of tun based on the series of semi-thin sections was prepared with IMARIS 8.2 software (Bitplane).

  • 177.
    Czernekova, Michaela
    et al.
    Kristianstad University, Faculty of Natural Science, Research environment Man & Biosphere Health (MABH). Kristianstad University, Faculty of Natural Science, Avdelningen för miljö- och biovetenskap. Charles University, Prague.
    Janelt, Kamil
    Poland.
    Student, Sebastian
    Poland.
    Jönsson, K. Ingemar
    Kristianstad University, Faculty of Natural Science, Research environment Man & Biosphere Health (MABH). Kristianstad University, Faculty of Natural Science, Avdelningen för miljö- och biovetenskap.
    Poprawa, Izabela
    Poland.
    A comparative ultrastructure study of storage cells in the eutardigrade Richtersius coronifer in the hydrated state and after desiccation and heating stress2018In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 13, no 8Article in journal (Refereed)
    Abstract [en]

    Tardigrades represent an invertebrate phylum with no circulatory or respiratory system.Their body cavity is filled with free storage cells of the coelomocyte-type, which are responsible for important physiological functions. We report a study comparing the ultrastructure of storage cells in anhydrobiotic and hydrated specimens of the eutardigrade Richtersius coronifer. We also analysed the effect of temperature stress on storage cell structure. Firstly, we verified two types of ultrastructurally different storage cells, which differ in cellular organelle complexity, amount and content of reserve material and connection to oogenetic stage. Type I cells were found to differ ultrastructurally depending on the oogenetic stage of the animal. The main function of these cells is energy storage. Storage cells of Type I were also observed in the single male that was found among the analysed specimens. The second cell type, Type II, found only in females, represents young undifferentiated cells, possibly stem cells. The two types of cells also differ with respect to the presence of nucleolar vacuoles,which are related to oogenetic stages and to changes in nucleolic activity during oogenesis. Secondly, this study revealed that storage cells are not ultrastructurally affected by six months of desiccation or by heating following this desiccation period. However, heating of the desiccated animals (tuns) tended to reduce animal survival, indicating that longterm desiccation makes these animals more vulnerable to heat stress. We confirmed the degradative pathways during the rehydration process after desiccation and heat stress. Our study is the first to document two ultrastructurally different types of storage cells in tardigrades and reveals new perspectives for further studies of tardigrade storage cells.

  • 178.
    Czernekova, Michaela
    et al.
    Kristianstad University, Research environment Man & Biosphere Health (MABH). Tjeckien.
    Jönsson, K. Ingemar
    Kristianstad University, Research environment Man & Biosphere Health (MABH). Kristianstad University, School of Education and Environment, Avdelningen för Naturvetenskap.
    Experimentally induced repeated anhydrobiosis in the Eutardigrade Richtersius coronifer2016In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 11, no 11, article id e0164062Article in journal (Refereed)
    Abstract [en]

    Tardigrades represent one of the main animal groups with anhydrobiotic capacity at any stage of their life cycle. The ability of tardigrades to survive repeated cycles of anhydrobiosis has rarely been studied but is of interest to understand the factors constraining anhydrobiotic survival. The main objective of this study was to investigate the patterns of survival of the eutardigrade Richtersius coronifer under repeated cycles of desiccation, and the potential effect of repeated desiccation on size, shape and number of storage cells. We also analyzed potential change in body size, gut content and frequency of mitotic storage cells. Specimens were kept under non-cultured conditions and desiccated under controlled relative humidity. After each desiccation cycle 10 specimens were selected for analysis of morphometric characteristics and mitosis. The study demonstrates that tardigrades may survive up to 6 repeated desiccations, with declining survival rates with increased numberof desiccations. We found a significantly higher proportion of animals that were unable to contract properly into a tun stage during the desiccation process at the 5th and 6th desiccations. Also total number of storage cells declined at the 5th and 6th desiccations, while no effect on storage cell size was observed. The frequency of mitotic storage cells tended to decline with higher number of desiccation cycles. Our study shows that the number of consecutive cycles of anhydrobiosis that R. coronifer may undergo is limited, with increased inability for tun formation and energetic constraints as possible causal factors.

  • 179.
    Czernekova, Michaela
    et al.
    Kristianstad University, School of Education and Environment, Avdelningen för Naturvetenskap. Kristianstad University, Research environment Man & Biosphere Health (MABH). Charles University, Prague.
    Jönsson, K. Ingemar
    Kristianstad University, Research environment Man & Biosphere Health (MABH). Kristianstad University, School of Education and Environment, Avdelningen för Naturvetenskap.
    Mitosis in storage cells of the eutardigrade Richtersius coronifer2016In: Zoological Journal of the Linnean Society, ISSN 0024-4082, E-ISSN 1096-3642, Vol. 178, no 4, p. 888-896Article in journal (Refereed)
    Abstract [en]

    Although tardigrades are sometimes reported as eutelic animals, mitosis has been reported in several somatic tissues of adult eutardigrades. The occurrence of cell division in storage cells is particularly interesting in light of the important role that these cells play in the physiology of tardigrades. We present data on the occurrence of mitosis in storage cells of the eutardigrade Richtersius coronifer (Richters, 1903), and analyse mitotic cells in relation to different body characteristics, including egg development stage, moulting, gut content, body length, number and size of oocytes, and shape and size of the storage cells. Mitosis was present in ~20% of all animals, and was more frequent in juveniles than in adults. The proportion of cells with mitosis (‘mitotic index’) was low: 0.76% in juveniles and 1.47% in adults. In juveniles, none of the measured phenotypic characters had significant predictive power for mitosis, whereas in adult animals in moult or in late egg developmental or post-laying stage were more likely to have mitotic storage cells. The association with the later part of the moulting process was particularly strong. The low mitotic index and the strong association with moulting suggests that mitosis in storage cells may be connected with somatic growth rather than cell renewal, and that the purpose of cell division may relate to a need of more cells to support the enlarged body after moulting. However, the specific life cycle of tardigrades, where energy intake and depletion, egg development, and moulting is highly intertwined and synchronized, make conclusions about the functional role of mitosis in storage cells difficult, however, and more studies are needed to reveal the mechanisms inducing mitosis in these interesting cells.

  • 180.
    Czernekova, Michaela
    et al.
    Kristianstad University, Research environment Man & Biosphere Health (MABH). Kristianstad University, School of Education and Environment, Avdelningen för Naturvetenskap.
    Jönsson, K. Ingemar
    Kristianstad University, Research environment Man & Biosphere Health (MABH). Kristianstad University, School of Education and Environment, Avdelningen för Naturvetenskap.
    Mitosis in storage cells of the eutardigrade Richtersius coronifer2015Conference paper (Refereed)
    Abstract [en]

    Tardigrades are often reported as eutelic animals, characterized by a constant cell number after maturity and growing by cell enlargement rather than by increased cell number. However, mitosis has been reported in some of the somatic tissues of adult eutardigrades, including the storage cells, and are therefore not strictly eutelic. Very few studies have investigated the presence of mitosis in tardigrades, and the occurrence of cell division in storage cells is particularly interesting in light of the important role that these cells may play in the physiology and immunology of tardigrades. We present data on the occurrence of mitosis in storage cells of the eutardigrade Richtersius coronifer and provide an analysis of storage cell mitosis in relation to different body characteristics. Specimens were examined for mitotic cells using in toto staining with aceto-lactic orcein, and the same animals were characterized with respect to egg development stage, number of oocytes, gut content, body size, and shape and size of the storage cells. Mitosis was present in ca. 30% of the animals. A large majority (3/4) of the animals with mitotic cells were found in specimens at moulting or directly after egg laying. Amount of gut content was associated with mitosis, with highest mitosis frequency (ca. 50%) in animals with an empty gut. These results for egg developmental stage (incl. moulting) and gut content are however not independent, since gut content generally decrease towards the end of the reproductive cycle. Other measured body characteristics did not influence the frequency of mitosis. In juveniles, mitotic cells were found in about half of the examined specimens. Our results suggest that proliferation of storage cells in R. coronifer is connected to the general life cycle dynamics, and provide a basis for more in depth analyses of the functional role and dynamics of storage cells in tardigrades.

  • 181.
    Czernekova, Michaela
    et al.
    Kristianstad University, School of Education and Environment, Avdelningen för Naturvetenskap. Kristianstad University, Research environment Man & Biosphere Health (MABH). Tjeckien.
    Jönsson, K. Ingemar
    Kristianstad University, School of Education and Environment, Avdelningen för Naturvetenskap. Kristianstad University, Research environment Man & Biosphere Health (MABH).
    Chajec, Lukasz
    Polen.
    Student, Sebastian
    Polen.
    Poprawa, Izabela
    Polen.
    The structure of the desiccated Richtersius coronifer (Richters, 1903)2017In: Protoplasma, ISSN 0033-183X, E-ISSN 1615-6102, Vol. 254, no 3, p. 1367-1377Article in journal (Refereed)
    Abstract [en]

    Tun formation is an essential morphological adaptation for entering the anhydrobiotic state in tardigrades, but its internal structure has rarely been investigated. We present the structure and ultrastructure of organs and cells in desiccated Richtersius coronifer by transmission and scanning electron microscopy, confocal microscopy, and histochemical methods. A 3D reconstruction of the body organization of the tun stage is also presented. The tun formation during anhydrobiosis of tardigrades is a process of anterior-posterior body contraction, which relocates some organs such as the pharyngeal bulb. The cuticle is composed of epicuticle, intracuticle and procuticle; flocculent coat; and trilaminate layer. Moulting does not seem to restrict the tun formation, as evidenced from tardigrade tuns that were in the process of moulting. The storage cells of desiccated specimens filled up the free inner space and surrounded internal organs, such as the ovary and digestive system, which were contracted. All cells (epidermal cells, storage cells, ovary cells, cells of the digestive system) underwent shrinkage, and their cytoplasm was electron dense. Lipids and polysaccharides dominated among reserve material of storage cells, while the amount of protein was small. The basic morphology of specific cell types and organelles did not differ between active and anhydrobiotic R. coronifer.

  • 182.
    Czernekova, Michaela
    et al.
    Kristianstad University, Faculty of Natural Science, Research environment Man & Biosphere Health (MABH). Kristianstad University, Faculty of Natural Science, Avdelningen för miljö- och biovetenskap. Czech republic.
    Jönsson, K. Ingemar
    Kristianstad University, Faculty of Natural Science, Research environment Man & Biosphere Health (MABH). Kristianstad University, Faculty of Natural Science, Avdelningen för miljö- och biovetenskap.
    Hajer, Jaromir
    Czech republic.
    Devetter, Miroslav
    Czech Republic..
    Evaluation of extraction methods for quantitative analysis of tardigrade populations in soil and leaf litter2018In: Pedobiologia, ISSN 0031-4056, E-ISSN 1873-1511, Vol. 70, p. 1-5Article in journal (Refereed)
    Abstract [en]

    Accurate quantitative analysis of soil tardigrades depends on a relevant extraction method. Over the years, a number of different methods have been used, but the efficiency of these methods has rarely been evaluated for soil and leaf litter tardigrades. Four methods of extraction were compared in this study: the light-cooling (L-C) extractor, the high-gradient (H-G), Baermann extractor, the non-gradient (N-G) Baermann extractor and sieves.The results indicate that light and temperature are significant factors influencing tardigrade extraction. The L-C and H-G extractors were more effective than sieves for all substrate categories. These extraction methods (L-C and H-G) therefore seem to be appropriate for quantitative studies of soil and leaf litter tardigrades.

  • 183.
    Czernekova, Michaela
    et al.
    Kristianstad University, School of Education and Environment, Avdelningen för Naturvetenskap. Kristianstad University, Research environment Man & Biosphere Health (MABH). Charles University, Prague.
    Tassidis, Helena
    Kristianstad University, School of Education and Environment, Avdelningen för Naturvetenskap. Kristianstad University, Research environment Man & Biosphere Health (MABH).
    Holm, Ingvar
    Kristianstad University, School of Education and Environment, Avdelningen för Naturvetenskap. Kristianstad University, Research environment Man & Biosphere Health (MABH).
    Jönsson, K. Ingemar
    Kristianstad University, School of Education and Environment, Avdelningen för Naturvetenskap. Kristianstad University, Research environment Man & Biosphere Health (MABH).
    Primary Culture of Tardigrade Storage Cells from Richtersius coronifer Richters, 19032016Conference paper (Refereed)
    Abstract [en]

    Coelomocytes are macrophage-like cells in the body cavity or the coelomic spaces of many invertebrates and play major roles in their physiology and immunology. Their structure, function and diversity, however, is still poorly understood.

    Tardigrades are micrometazoans inhabiting a wide variety of environments and with an ability to survive extreme conditions. Coelomocytes (“storage cells”) represent an important part of tardigrade physiology, storing and distributing energy and possibly also having immunological functions. Few studies of tardigrade cell biology have been reported and neither primary nor continuous cell cultures have been established. Tardigrades are normally found and also cultured in an environment rich in microorganisms, some of which may even be of symbiotic value.

    In this study we have tried to establish a primary culture of storage cells in the eutardigrade Richtersius coronifer. Different cell media and concentrations of fetal bovine serum (FBS) were tested. Extracting cells from the tardigrades in an antiseptical environment is challenging since it has to be done under a microscope and contamination from the tardigrades surface is also a problem. To avoid this we tried culturing with high concentrations of antibiotics and antimycotics. We managed to keep the cells viable for up to 18 days in Grace insect medium with 10 % FBS at 20-22°C. The medium was changed every third day. 10x Antibiotic-Antimycotic and 5x of Penicillin-Streptomycin were used to minimize contamination. These concentrations reduce the bacterial abundance, but contamination with fungi was still an issue. Cell morphology evaluation was performed daily and no obvious toxic effects on the cells was observed. Cell viability and cell division were evaluated with Trypan blue staining and cell counting in a haemocytometer. The results indicate that the cells are viable and that some cell division occurs, however more studies need to be performed to confirm this. Still, this study provides the first evidence that primary cultures of storage cells from tardigrades are possible to establish, but the culturing method has to be refined to avoid contamination.

  • 184.
    Dahlin, Jon-Erik
    et al.
    Kungliga Tekniska Högskolan.
    Persson, Christel
    Kristianstad University, Faculty of Education, Research environment Learning in Science and Mathematics (LISMA). Kristianstad University, School of Education and Environment, Avdelningen för Naturvetenskap.
    Persson, Torsten
    Philipson, Sten
    Strömstad Akademi.
    Ammenberg, Jonas
    Linköpings universitet.
    Baumann, Henrikke
    Chalmers.
    Tillman, Anne-Marie
    Chalmers.
    Hållbar utveckling, CSR och livscykelanalys: kurs 1TG2402016Book (Other academic)
  • 185.
    Dalby, Lars
    et al.
    Department of Bioscience, Aarhus University.
    Söderquist, Pär
    Kristianstad University, School of Education and Environment, Avdelningen för Naturvetenskap. Kristianstad University, Forskningsmiljön Man and Biosphere Health (MABH).
    Christensen, Thomas K.
    Department of Bioscience, Aarhus University.
    Clausen, Preben
    Department of Bioscience, Aarhus University.
    Einarsson, Árni
    Myvatn Research Station, Iceland.
    Elmberg, Johan
    Kristianstad University, School of Education and Environment, Avdelningen för Naturvetenskap. Kristianstad University, Forskningsmiljön Man and Biosphere Health (MABH).
    Fox, Anthony D.
    Department of Bioscience, Aarhus University.
    Holmqvist, Niklas
    Swedish Association for Hunting and Wildlife Management, Öster Malma, Nyköping.
    Langendoen, Tom
    Wetlands International, Wageningen.
    Lehikoinen, Aleksi
    Finnish Museum of Natural History, University of Helsinki.
    Lindström, Åke
    Department of Biology,Biodiversity, Lund University.
    Lorentsen, Svein-Håkon
    Norwegian Institute for Nature Research, Trondheim.
    Nilsson, Leif
    Department of Biology, Biodiversity, Lund University.
    Pöysä, Hannu
    Finnish Game and Fisheries Research Institute, Joensuu Game and Fisheries Research.
    Sigfússon, Arnór Þ.
    Verkís, Reykjavik.
    Svenning, Jens-Christian
    Ecoinformatics & Biodiversity Group, Department of Bioscience, Aarhus University.
    The status of the Nordic populations of the Mallard (Anas platyrhynchos) in a changing world2013In: Ornis Fennica, ISSN 0030-5685, Vol. 90, no 1, p. 2-15Article in journal (Refereed)
    Abstract [en]

    Dabbling ducks (Anas spp.) are importantmigratory quarry species, protected as a shared resource under international legislation. However, there is a lack of sufficient high-quality data on vital demographic rates and long-term trends in numbers to judge the conservation status of many duck populations at the flyway level. In response to reported declines in the North-West European flyway population of theMallard, we compiled available data on this species in the Nordic countries up to 2010. Generally, national breeding numbers showed increasing trends, wintering abundance showed variable trends, and productivitymeasures indicated stable or increasing trends.Major knowledge gaps were identified, namely the size of hunting bags, the influence of the released Mallards and the role of short-stopping in explaining changing patterns of wintering abundance across the North-West European flyway. Numerically the Nordic breeding population appears in “good condition”, and the wintering numbers have been either stable or increasing in the last two decades. The annual number of releases needs to be determined in order to judge the sustainability of the current levels of exploitation. Overall, none of the indicators showed alarming signs for the Mallard population in the Nordic countries when considered in isolation. However, the widespread decline in wintering numbers elsewhere across North-western Europe requires urgent pan-European action.

  • 186.
    Danell, Kjell
    et al.
    Sveriges lantbruksuniversitet, Umeå.
    Bergström, Roger
    Skogforsk, Uppsala.
    Elmberg, Johan
    Kristianstad University, School of Education and Environment.
    Emanuelsson, Urban
    Sveriges lantbruksuniversitet, Alnarp.
    Christiernsson, Anna
    Luleå tekniska universitet.
    Viltet2010In: Vilt, människa, samhälle / [ed] Danell, Kjell, Bergström, Roger, Stockholm: Liber , 2010, p. 17-31Chapter in book (Other (popular science, discussion, etc.))
  • 187.
    Davidsson, Paul
    et al.
    School of Engineering, Blekinge Institute of Technology.
    Holmgren, Johan
    School of Engineering, Blekinge Institute of Technology.
    Kyhlbäck, Hans
    School of Engineering, Blekinge Institute of Technology.
    Mengistu, Dawit
    School of Engineering, Blekinge Institute of Technology.
    Persson, Marie
    School of Engineering, Blekinge Institute of Technology.
    Applications of agent based simulation2007In: Multi-agent-based simulation VII: International workshop, MABS 2006, Hakodate, Japan, May 8, 2006, revised and invited papers / [ed] Luis Antunes & Keiki Takadama, Berlin: Springer Berlin/Heidelberg, 2007, p. 15-27Conference paper (Refereed)
    Abstract [en]

    This paper provides a survey and analysis of applications of Agent Based Simulation (ABS). A framework for describing and assessing the applications is presented and systematically applied. A general conclusion from the study is that even if ABS seems a promising approach to many problems involving simulation of complex systems of interacting entities, it seems as the full potential of the agent concept and previous research and development within ABS often is not utilized. We illustrate this by providing some concrete examples. Another conclusion is that important information of the applications, in particular concerning the implementation of the simulator, was missing in many papers. As an attempt to encourage improvements we provide some guidelines for writing ABS application papers.

  • 188.
    Davis, Brian
    et al.
    USA.
    Kaminski, Rick
    USA.
    Eichholz, Mike
    USA.
    Arzel, Celine
    Finland.
    Bearhop, Stuart
    England.
    Eadie, John
    USA.
    Elmberg, Johan
    Kristianstad University, School of Education and Environment, Avdelningen för Naturvetenskap.
    Fox, Tony
    Danmark.
    Guillemain, Matt
    Frankrike.
    Pearse, Aaron
    USA.
    Stafford, J
    USA.
    Plenary: Waterfowl habitat use and selection: knowledge gained and future science and conservation needs2013In: 6th North American Duck Symposium, Memphis, TN, January 27-31, 2013: ecology and management of North American waterfowl, 2013, p. 9-Conference paper (Refereed)
  • 189.
    Davranche, Aurélie
    et al.
    Frankrike.
    Arzel, Céline
    Frankrike.
    Pöysä, Hannu
    Finland.
    Nummi, Petri
    Finland.
    Elmberg, Johan
    Kristianstad University, School of Education and Environment, Avdelningen för Naturvetenskap.
    Clausen, Preben
    Danmark.
    Pellikka, Petri
    Finland.
    Assessing habitat suitability for waterbirds along the European flyway using satellite remote sensing2012In: Third Pan-European Duck Symposium, abstract book and progamme, 2012, p. 51-Conference paper (Refereed)
  • 190.
    Davranche, Aurélie
    et al.
    Erlangen-Nürnberg University Institute of Geography.
    Arzel, Céline
    Department of Biology, University of Turku.
    Pöysä, Hannu
    Nummi, Petri
    Elmberg, Johan
    Kristianstad University, School of Education and Environment.
    Clausen, Preben
    Pellikka, Petri
    Lefebvre, Gaëtan
    Poulin, Brigitte
    Space based tools to monitor the habitats of migratory waterbirds2010In: The abstract book: Symposium : The global environmental change: messages from birds. Espoo, 17-19 November, 2010, p. 44-Conference paper (Other academic)
    Abstract [en]

    Natural fluctuations in the availability of suitable habitat coupled with anthropogenic activities (hunting, agriculture, tourism, urbanism) and anticipated modifications due to climate change confront migratory waterbirds with a formidable challenge. Among them, dabbling ducks, greatly rely on local exogenous resources to fulfil their energy requirements. Habitat suitability along their flyway is of primary importance as any change might induce dramatic effects on individual survival and breeding success. Although, the monitoring of such sensitive flooded areas that are wetlands stopover sites is usually complex, space based techniques, with an exhaustive and systematic covering of the territory and a periodical data acquisition, can explore cost-efficiently the ecological conditions for migratory species in these environments. Hence, multiseason reflectance data from radiometrically and geometrically corrected multispectral SPOT-5 scenes, combined with thorough field campaigns and land cover digitizing using data mining, can provide robust tools for habitat monitoring and help the conservation of wetlands for migrants.

  • 191.
    Dessborn, Lisa
    et al.
    Kristianstad University, School of Education and Environment.
    Brochet, A. L.
    Office National de la Chasse et de la Faune Sauvage, CNERA Avifaune Migratrice, La Tour du Valat, Le Sambuc, Arles.
    Elmberg, Johan
    Kristianstad University, School of Education and Environment.
    Legagneux, P.
    Département de Biologie and Centre d’Études Nordiques, Pavillon Vachon Université Laval, Québec.
    Gauthier-Clerc, M.
    Centre de Recherche de la Tour du Valat, Le Sambuc, Arles,.
    Guillemain, M.
    Office National de la Chasse et de la Faune Sauvage, CNERA Avifaune Migratrice, La Tour du Valat, Le Sambuc, Arles.
    Geographical and temporal patterns in the diet of pintail Anas acuta, wigeon Anas penelope, mallard Anas platyrhynchos and teal Anas crecca in the Western Palearctic2011In: European Journal of Wildlife Research, ISSN 1612-4642, E-ISSN 1439-0574, Vol. 57, no 6, p. 1119-1129Article in journal (Refereed)
    Abstract [en]

    Dabbling ducks are important quarry species, and as a result, they are relatively well studied. Over the last century, considerable effort has been made to describe their diet and food requirements. In this review, we compile present knowledge about the diet of four widespread dabbling ducks (wigeon, pintail, mallard and teal) in the Western Palearctic. Previous diet research has a spatio-temporal bias towards autumn/winter and the western parts of Europe. The limited number of studies from the breeding season reveals an increase in invertebrates in the diet compared to other seasons, but with some differences between adults and ducklings. Adult ducks eat a larger proportion of benthic invertebrates, whereas ducklings feed relatively more on emerging invertebrates. The most important plant species (seeds) based on frequency occurrence was found to vary with a geographic gradient. Carex spp., Hordeum vulgare and Hippuris vulgaris are common in the diet of birds at northern latitudes, whereas taxa such as Oryza sativa, Potamogeton pectinatus and Scirpus spp. are common in the south. The reviewed studies are based on the contents of different parts of the digestive system and on a variety of methods to quantify food items. The variations in sampling techniques and shortage of articles from the breeding season and some geographic regions highlight the need for future studies. In the future, it is important to standardize sampling techniques to improve the possibility to compare studies and to obtain a more representative view of the diet of dabbling ducks in Europe.

  • 192.
    Dessborn, Lisa
    et al.
    Kristianstad University, Research environment Man & Biosphere Health (MABH). Kristianstad University, Faculty of Natural Science, Avdelningen för miljö- och biovetenskap.
    Elmberg, Johan
    Kristianstad University, Research environment Man & Biosphere Health (MABH). Kristianstad University, Faculty of Natural Science, Avdelningen för miljö- och biovetenskap.
    Bidrar gäss och svanar  till övergödning av våtmarker?2018In: Fakta för förvaltare: gäss och svanar: kunskapssammanställning om bete, övergödning, smittspridning och skyddsjakt / [ed] Johan Elmberg & Johan Månsson, Stockholm: Naturvårdsverket , 2018, p. 33-47Chapter in book (Other academic)
    Abstract [en]

    • Swans and geese occur in larger numbers near more people than ever before, in Sweden as well as in Western Europe.

    • Increasing populations sometimes lead to problems and conflicts. On agricultural land geese and swans can cause costly damage to growing crops. Intense grazing by these birds may also affect natural vegetation, sometimes leading to conflict with conservation and biodiversity goals.

    • Geese and swans are obligate herbivores, consuming leaves, stems, seeds and root parts of terrestrial and aquatic plants.

    • Grazing on growing crops may cause conflicts of interest also when geese and swans congregate in large numbers in wetlands adjacent to cropland.

    • Geese and swans provide a multitude of ecosystem services, for example viewing, hunting, meat, and eco-tourism revenues. GEESE AND SWANS AS VECTORS OF NUTRIENTS

    • Geese and swans eat large amounts of plant material, have a relatively inefficient digestive system, and produce a lot of droppings.

    • These birds find most of their food on land, but spend a large part of the day  resting on wetlands, where they also defecate.

    • In autumn, winter and spring most geese and swans make daily flights between feeding and roost sites, thereby becoming vectors of nutrients to wetlands and lakes

  • 193.
    Dessborn, Lisa
    et al.
    Kristianstad University, School of Education and Environment, Avdelningen för Naturvetenskap.
    Elmberg, Johan
    Kristianstad University, School of Education and Environment, Avdelningen för Naturvetenskap.
    Är ökande gåsstammar verkligen en skitsak?2007In: Vår fågelvärld, ISSN 0042-2649, Vol. 66, no 7, p. 11-14Article in journal (Other (popular science, discussion, etc.))
  • 194.
    Dessborn, Lisa
    et al.
    Kristianstad University, School of Education and Environment.
    Elmberg, Johan
    Kristianstad University, School of Education and Environment.
    Englund, Göran
    Department of Ecology and Environmental Science, Umeå University.
    Pike predation affects breeding success and habitat selection of ducks2011In: Freshwater Biology, ISSN 0046-5070, E-ISSN 1365-2427, Vol. 56, no 3, p. 579-589Article in journal (Refereed)
    Abstract [en]

    1. Fish and ducks often belong to the same local food web, and several studies indicate that there is a general negative effect of fish on breeding ducks. This pattern has so far been addressed mainly within the framework of competition for common invertebrate prey, while predation by large fish as a force behind settlement and abundance patterns in ducks remains largely unknown. This is the first study to address the effect of fish predation on breeding ducks, isolated from that of competition, and the first experiment to explore the ability of ducks to identify and avoid lakes with high risk of fish predation. 2. We used a before-after control-impact design and 11 naturally fishless lakes. Waterfowl on the lakes were surveyed during the breeding season of 2005. Large adult pike (Esox lucius) were added to two lakes in early spring 2008, and waterfowl surveys were repeated on all 11 lakes. 3. Pike introduction did not affect the number of pairs on lakes during the nesting season in any of three focal duck species (mallard Anas platyrhynchos, teal Anas crecca, and goldeneye Bucephala clangula). During the brood-rearing season, however, there was a decrease in duck days in teal and goldeneye in lakes with pike, with similar trends observed in mallard. The number of goldeneye ducklings was also significantly lower in lakes with pike. We were unable to determine whether the response was attributable to direct pike predation or to broods leaving experimental lakes, but in either case, our study demonstrates high fitness costs for ducks breeding on lakes with pike. 4. The apparent inability of nesting ducks to detect pike and the clear fitness implications may influence the annual recruitment of ducks on a larger scale as pike are both common and widespread. Vegetation complexity and food abundance are likely to be of overriding importance when breeding ducks are choosing a nesting site. As pike have a strong influence on breeding birds, relying on vegetation and cues of food abundance, while ignoring indicators of predation risk from fish, could lead to lakes with pike acting as an ecological trap.

  • 195.
    Dessborn, Lisa
    et al.
    Kristianstad University, School of Health and Society.
    Elmberg, Johan
    Kristianstad University, School of Education and Environment.
    Englund, Göran
    Department of Ecology and Environmental Science, Umeå University.
    The effects of pike predation on lake use and reproductive success of ducks: an experimental study in boreal lakes2009In: Abstracts, 2nd Pan-European Duck Symposium, 2009, p. 36-Conference paper (Refereed)
  • 196.
    Dessborn, Lisa
    et al.
    Kristianstad University, School of Education and Environment, Avdelningen för Naturvetenskap.
    Elmberg, Johan
    Kristianstad University, School of Education and Environment, Avdelningen för Naturvetenskap.
    Nummi, Petri
    Finland.
    Pöysä, Hannu
    Finland.
    Sjöberg, Kjell
    SLU, Umeå.
    Hatching in dabbling ducks and emergence in Chironomids: a case of predator-prey synchrony?2011Conference paper (Refereed)
  • 197.
    Dessborn, Lisa
    et al.
    Kristianstad University, School of Education and Environment.
    Elmberg, Johan
    Kristianstad University, School of Education and Environment.
    Nummi, Petri
    Department of Forest Ecology, University of Helsinki.
    Pöysä, Hannu
    Finnish Game and Fisheries Research Institute, Joensuu Game and Fisheries Research.
    Sjöberg, Kjell
    Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences, Umeå.
    Hatching in dabbling ducks and emergence in chironomids: a case of predator-prey synchrony?2009In: Hydrobiologia, ISSN 0018-8158, E-ISSN 1573-5117, Vol. 636, no 1, p. 319-329Article in journal (Refereed)
    Abstract [en]

    It has been hypothesized that dabbling ducks (Anas spp.) time breeding to coincide with annual regional peaks in emerging dipterans, especially Chironomidae, which are important prey for newly hatched ducklings. However, this hypothesis has never been evaluated in a replicated lake-level study, including year effects in emergence patterns. We collected duck and invertebrate data from 12 lakes during the nesting seasons 1989-1994 in a watershed in southern Finland. The oligotrophic study lakes are typical of the boreal Holarctic, as are the three focal duck species: mallard Anas platyrhynchos L., widgeon Anas penelope L and teal Anas crecca L. Hatching of ducklings showed a clear peak in relation to ambient phenology (annual ice-out date of lakes), whereas chironomid emergence was more erratic and showed no clear peak at the lake level, although total watershed-level emergence was somewhat higher before and long after the duck hatching peak. Thus, we find no evidence that ducklings hatch in synchrony with abundance peaks of emerging chironomids. There was large within-year temporal variation in chironomid emergence among lakes, but this was not correlated with ambient temperature. The rank of individual lakes with respect to the abundance of emerging chironomids was consistent among as well as within years, a predictability that ought to make adaptive lake choice by ducks possible. On the lake level, there was a positive correlation between the total amount of emerging chironomids and brood use. We argue that emergence patterns of chironomids on typical boreal lakes are neither compressed nor predictable enough to be a major selective force on the timing of egg-laying and hatching in dabbling ducks. Despite spatial (among-lake) patterns of abundance of emerging chironomids being predictable within and among years, the observed pattern of brood use suggests that other factors, e.g. habitat structure, also affect lake choice.

  • 198.
    Dessborn, Lisa
    et al.
    Kristianstad University, School of Education and Environment, Avdelningen för Naturvetenskap.
    Englund, Göran
    Umeå universitet.
    Elmberg, Johan
    Kristianstad University, School of Education and Environment, Avdelningen för Naturvetenskap.
    Arzel, Céline
    Frankrike.
    Responses of mallard ducklings towards aerial, aquatic and terrestrial predators2012In: Third Pan-European Duck Symposium: abstract book and programme, 2012, p. 17-Conference paper (Refereed)
  • 199.
    Dessborn, Lisa
    et al.
    Kristianstad University, School of Education and Environment, Avdelningen för Naturvetenskap. Kristianstad University, Forskningsmiljön Man and Biosphere Health (MABH).
    Englund, Göran
    Department of Ecology and Environmental Science, Umeå University.
    Elmberg, Johan
    Kristianstad University, School of Education and Environment, Avdelningen för Naturvetenskap. Kristianstad University, Forskningsmiljön Man and Biosphere Health (MABH).
    Arzél, Celine
    Section of Ecology, Department of Biology, University of Turku.
    Innate responses of mallard ducklings towards aerial, aquatic and terrestrial predators2012In: Behaviour, ISSN 0005-7959, E-ISSN 1568-539X, Vol. 149, no 13-14, p. 1299-1317Article in journal (Refereed)
    Abstract [en]

    Reproductive success in ducks is strongly influenced by predation on the breeding grounds. Ducklings are targeted by a range of terrestrial, aerial and aquatic predators, giving a strong selective advantage to individuals and broods that have effective ways to avoid predation. In experiments on naive mallard (Anas platyrhynchos) ducklings without an accompanying adult female we investigated the innate ability to identify and avoid threats at varying intensity from aerial, aquatic and terrestrial predators. Ducklings displayed increased vigilance in response to pre-recorded calls of predatory birds, representing a low level of threat. They did not react to visual and olfactory stimuli generated by motionless northern pike (Esox lucius). Neither did they show a strong response to caged American mink (Neovison vison) (visual and olfactory stimuli), although they avoided the area with the mink, indicating a certain level of recognition. High intensity threats were simulated by staging attacks from aerial (goshawk, Accipiter gentilis) and aquatic predators (northern pike). The aerial attack made ducklings dive and scatter under water, whereas the response to attack by pike was to run on the water and scatter in different directions. The lack of response to a ‘passive’ pike and the rather weak avoidance of mink indicate that olfactory cues are not as important in identifying a potential predatory threat by ducklings as are auditory cues. Visual cues appear to be of little importance unless they are combined with movement, and a clear response is only triggered when the intensity of predator threat is high. Mallard ducklings, thus, show an innate capacity to adjust anti-predator behaviour to different predator types and to threat intensity. Our study highlights the general trade-off between foraging needs and predator avoidance, but also second-order trade-offs in which innate avoidance behaviour towards one type of predator may increase predation risk from another.

  • 200.
    Dessborn, Lisa
    et al.
    Kristianstad University, School of Education and Environment, Avdelningen för Naturvetenskap. Kristianstad University, Research environment Man & Biosphere Health (MABH).
    Hessel, Rebecca
    Kristianstad University, School of Education and Environment, Avdelningen för Naturvetenskap. Kristianstad University, Research environment Man & Biosphere Health (MABH).
    Elmberg, Johan
    Kristianstad University, School of Education and Environment, Avdelningen för Naturvetenskap. Kristianstad University, Research environment Man & Biosphere Health (MABH).
    Geese as vectors of nitrogen and phosphorus to freshwater systems2016In: INLAND WATERS, ISSN 2044-2041, E-ISSN 2044-205X, Vol. 6, no 1, p. 111-122Article in journal (Refereed)
    Abstract [en]

    Many goose populations have increased dramatically over the past decades, which may influence inland waters used as roost sites. We reviewed the role of geese in the influx of nitrogen and phosphorus to freshwater systems. Several methods have been used to estimate guanotrophication impacts of geese. Water and sediment analysis have been conducted in areas of high and low geese presence; however, productive wetlands tend to attract more birds, and the causality is therefore ambiguous. Faecal addition experiments have attempted to estimate the impacts of droppings on water chemistry, sediments, algal growth, or invertebrate densities. The most common method of estimating goose guanotrophication is by extrapolation, usually based on multiplication of faecal production and its nutrient content. Based on such studies and those including information about daily migration patterns, we developed an approach to improve estimates of the nutrient contribution of geese. The relative role of geese in wetland eutrophication is also affected by the influx from alternative sources. The greatest guanotrophication impacts are likely found in areas with few alternative nutrient sources and with large goose flocks. Limited inflow and outflow of a freshwater system or a scarcity of wetland roosts may also increase problems at a local scale. Although several studies have looked at the impacts of geese on, for example, water chemistry or soil sediments, the effects are often smaller than expected, in part because no study to date has assessed the ecosystem response by including impacts on all levels, including water nutrient levels, nutrient sedimentation, chlorophyll content, and zooplankton response.

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