819 research outputs found
Systematic revision of the Chlamydinae (Pectinidae, Bivalvia, Mollusca) of the European Cretaceous. 1. <i>Camptonectes</i>
This paper is the first part of a series dealing with the systematic revision of the European Cretaceous Chlamydinae (Pectinidae, Bivalvia, Mollusca). Here, seven species of the genus Camptonectes Agassiz, L. in Meek, F. B., 1864 and of the subgenus Boreionectes Zakharov, V. A., 1965 are described : C. (C.) cottaldinus (D'Orbigny, A., 1847), C. (C.) striatopunctatus (Roemer, F. A., 1839), C. (C.) virgatus (Nilsson, S., 1827), C. (C.) gaultinus (Woods, H. , 1902), C. (B.) cinctus (Sowerby, J., 1822), C. (B.) dubrisiensis (Woods, H. , 1902), C. ? milleri (Sowerby, J. de C, 1836)
Population dynamics
Increases or decreases in the size of populations over space and time are, arguably, the motivation for much of pure and applied ecological research. The fundamental model for the dynamics of any population is straightforward: the net change over time in the abundance of some population is the simple difference between the number of additions (individuals entering the population) minus the number of subtractions (individuals leaving the population). Of course, the precise nature of the pattern and process of these additions and subtractions is often complex, and population biology is often replete with fairly dense mathematical representations of both processes. While there is no doubt that analysis of such abstract descriptions of populations has been of considerable value in advancing our, there has often existed a palpable discomfort when the ‘beautiful math’ is faced with the often ‘ugly realities’ of empirical data. In some cases, this attempted merger is abandoned altogether, because of the paucity of ‘good empirical data’ with which the theoretician can modify and evaluate more conceptually–based models. In some cases, the lack of ‘data’ is more accurately represented as a lack of robust estimates of one or more parameters. It is in this arena that methods developed to analyze multiple encounter data from individually marked organisms has seen perhaps the greatest advances. These methods have rapidly evolved to facilitate not only estimation of one or more vital rates, critical to population modeling and analysis, but also to allow for direct estimation of both the dynamics of populations (e.g., Pradel, 1996), and factors influencing those dynamics (e.g., Nichols et al., 2000). The interconnections between the various vital rates, their estimation, and incorporation into models, was the general subject of our plenary presentation by Hal Caswell (Caswell & Fujiwara, 2004). Caswell notes that although interest has traditionally focused on estimation of survival rate (arguably, use of data from marked individuals has been used for estimation of survival more than any other parameter, save perhaps abundance), it is only one of many transitions in the life cycle. Others discussed include transitions between age or size classes, breeding states, and physical locations. The demographic consequences of these transitions can be captured by matrix population models, and such models provide a natural link connecting multi–stage mark–recapture methods and population dynamics. The utility of the matrix approach for both prospective, and retrospective, analysis of variation in the dynamics of populations is well–known; such comparisons of results of prospective and retrospective analysis is fundamental to considerations of conservation management (sensu Caswell, 2000). What is intriguing is the degree to which these methods can be combined, or contrasted, with more direct estimation of one or more measures of the trajectory of a population (e.g., Sandercock & Beissinger, 2002). The five additional papers presented in the population dynamics session clearly reflected these considerations. In particular, the three papers submitted for this volume indicate the various ways in which complex empirical data can be analyzed, and often combined with more classical modeling approaches, to provide more robust insights to the dynamics of the study population. The paper by Francis & Saurola (2004) is an example of rigorous analysis and modeling applied to a large, carefully collected dataset from a long–term study of the biology of the Tawny Owl. Using a combination of live encounters and dead recoveries, the authors were able to separate the relative contributions of various processes (emigration, mortality) on variation in survival rates. These analyses were combined with periodic matrix models to explore comparisons of direct estimation of changes in population size (based on both census and mark–recapture analysis) with model estimates. The utility of combining sources of information into analysis of populations was the explicit subject of the other two papers. Gauthier & Lebreton (2004) draw on a long–term study of an Arctic–breeding Goose population, where both extensive mark–recapture, ring recovery, and census data are available. The primary goal is to use these various sources of information to to evaluate the effect of increased harvests on dynamics of the population. A number of methods are compared; most notably they describe an approach based on the Kalman filter which allows for different sources of information to be used in the same model, that is demographic data (i.e. transition matrix) and census data (i.e. annual survey). They note that one advantage of this approach is that it attempts to minimize both uncertainties associated with the survey and demographic parameters based on the variance of each estimate. The final paper, by Brooks, King and Morgan (Brooks et al., 2004) extends the notion of the combining information in a common model further. They present a Bayesian analysis of joint ring–recovery and census data using a state–space model allowing for the fact that not all members of the population are directly observable. They then impose a Leslie–matrix–based model on the true population counts describing the natural birth–death and age transition processes. Using a Markov Chain Monte Carlo (MCMC) approach (which eliminates the need for some of the standard assumption often invoked in use of a Kalman filter), Brooks and colleagues describe methods to combine information, including potentially relevant covariates that might explain some of the variation, within a larger framework that allows for discrimination (selection) amongst alternative models. We submit that all of the papers presented in this session indicate clearly significant interest in approaches for combining data and modeling approaches. The Bayesian framework appears a natural framework for this effort, since it is able to not only provide a rigorous way to evaluate and integrate multiple sources of information, but provides an explicit mechanism to accommodate various sources of uncertainty about the system. With the advent of numerical approaches to addressing some of the traditionally ‘tricky’ parts of Bayesian inference (e.g., MCMC), and relatively user–friendly software, we suspect that there will be a marked increase in the application of Bayesian inference to the analysis of population dynamics. We believe that the papers presented in this, and other sessions, are harbingers of this trend
The quantitative study of marked individuals in ecology, evolution and conservation biology: a foreword to the EURING 2003 Conference
Few fields in modern ecology have developed as fast as the analysis of marked individuals in the study of wild animal populations (Seber & Schwarz, 2002). This is the topic of EURING Conferences, which from 1986 have been the premier forum for advances in capture–recapture methodology. In this sense, EURING Conferences still maintain the flavour that originally inspired scientific meetings: to disseminate the very last findings, ideas and results on the field. Traditionally, EURING Conferences have been published in the form of Proceedings, which because of their relevant content, become a required reading to anyone interested in the capture–recapture methodology.
EURING 2003 was held in Radolfzell (Germany), hosted by the Max Planck Research Centre for Ornithology, and the Proceedings appear as a special issue of Animal Biodiversity and Conservation. The full title of the 2003 meeting was "The quantitative study of marked individuals in ecology, evolution and conservation biology", which stands for one of the main aims of the meeting: to establish the capture-recapture approach as one of the standard methodologies in studies within these fields. One of the shared views is that capture–recapture methodologies have reached a considerable maturity, but the need still exists to spread their use as a "standard" methodology. The nice review paper by Lebreton et al. (1993) in Trends in Ecology and Evolution is still applicable, in that general ecologists and evolutionary biologists still resist their general use. The same applies to conservation biology, where the analysis of marked individuals may also be a key tool in its development. We hope, with the spread of 2003 Proceedings, to help to fill this gap.
The Proceedings follow the same general structure as the Conference. We organised the EURING meeting in 10 technical sessions, covering what we considered as fastest growing areas in the field. We appointed for each session, two chairs, which were charged with selecting 4–7 talks on the topic of their session. Each session additionally included a plenary conference intended to summarise or to provide a general but synthetic flavour of the topic. As a novelty in EURING conferences, we asked session chairs to include at least one talk dealing with study species other than birds. This is the result of a heated but fruitful discussion at EURING 2000 in Point Reyes, and fits with the general aim to spread the capture–recapture methodology beyond zoological groups: although EURING as an organization, deals with birds, and conferences have traditionally focused on this group, the capture–recapture approach is becoming a standard way to address biologically relevant questions on populations and individuals (Schwarz, 2002), for any zoological group. This volume, contains several nice examples of taxa other than birds.
As far as possible, we selected chairs so that each session was delineated with a good balance between the biological and the statistician emphasis. This balance has in fact characterised EURING conferences, which in addition to the workshop atmosphere always present, has lead to very fruitful exchanges. Session chairs were also asked to act as editors for the papers within their session. All the papers were hence subjected to peer review, as in any other issue of Animal Biodiversity and Conservation, and presentation of the paper in the Conference did not assure publication in the Proceedings. This has lead to an even higher quality of the papers presented at the Conference. Editors were additionally asked to write a short summary on their session. Given that these summaries also present the views of the Editors on the different topics presented, we have preferred each introduction to appear as a short paper in the front of each one of the sessions, so that it can be cited as a regular paper.
The Proceedings start with the Honour Speaker Talk by James Nichols (Nichols, 2004). This talk is traditionally the last one in the Conference, but we think that it nicely summarises how and why capture–recapture has developed to its current healthy state. The talk is in fact a tribute to David Anderson, to whom, as Nichols says, all of us are more or less in debt. Hence, we have preferred to move the Honour Talk to the front position of the Proceedings, and we would like this to be our humble tribute to David. At the end of the Proceedings appear a few papers which were presented in poster format, and a paper summarising several of the main topics presented at the traditional short course on capture–recapture, this time organized by the unflagging Evan Cooch.
We would like to thank all the people who helped in one way or another to the successful completion of the EURING Conference and the Proceedings. We thank to the Session Chairs, their dedication and enthusiasm in organizing the sessions and also in editing the different papers. All their names appear in the front page of the Proceedings as credits. We thank Wolfgang Fiedler for the local organization of the event: a very difficult and exhausting task that is not always properly recognized. Jean Clobert, although unfortunately unable to attend the Conference, supported us with ideas and friendship meanwhile preparing the scientific program. Evan Cooch maintained the always successful web page (which probably will also become a classic in EURING conferences…), and organized the traditional course on capture–recapture.
Charles Francis very efficiently organized the poster session and acted as editor for the papers sent for publication. Finally we thank the Ministerio de Ciencia y TecnologÃa for financial support to the publication of this special issue of Animal Biodiversity and Conservation (B.O.S. 2002–12283–E) and to the Natural History Museum of Barcelona for their support
Systematic revision of <i>Entolium</i>, <i>Propeamussium</i> (Amusiidae) and <i>Syncyclonema</i> (Pectinidae, Bivalvia, Mollusca) of the European boreal Cretaceous
The present paper contains a systematic revision of the genera Entolium and Propeamussium (Amusiidae) and Syncyclonema (Pectinidae, Bivalvia, Mollusca) in European Cretaceous boreal seas.In Entolium two species are described, in Propeamussium one, and in Syncyclonema eight of which one (S. hagenowi) is new to science, two (S. gamsensis and S. haggi) are renamed and a former variety is given specific status (S. haldonensis).Stress is laid on redefining the species, mostly along biological lines. Material has been studied from as many localities as possible; a nomenclatorial critical revision is undertaken; type-specimens have been located; type-strata and type-localities are indicated
Inaugurating a Dutch Napoleon? Conservative criticism of the 1815 constitution of the United Kingdom of The Netherlands
International audienc
Mycoplasmal conjunctivitis in wild songbirds: the spread of a new contagious disease in a mobile host population.
A new mycoplasmal conjunctivitis was first reported in wild house finches (Carpodacus mexicanus) in early 1994. The causative agent was identified as Mycoplasma gallisepticum (MG), a nonzoonotic pathogen of poultry that had not been associated with disease in wild songbirds. Since the initial observations of affected house finches in the mid-Atlantic region, the disease has become widespread and has been reported throughout the eastern United States and Canada. By late 1995, mycoplasmal conjunctivitis had spread to an additional species, the American goldfinch (Carduelis tristis). This new disease exemplifies the rapid spread of a pathogen following introduction into a mobile wildlife population and provides lessons that may apply to emerging human diseases
Complete invasion of <i>Impatiens glandulifera</i> in the Scheldt basin - prospects for 'hydrological control'
Serum levels and removal by haemodialysis and haemodiafiltration of tryptophan-derived uremic toxins in ESKD patients
Tryptophan is an essential dietary amino acid that originates uremic toxins that contribute to end-stage kidney disease (ESKD) patient outcomes. We evaluated serum levels and removal during haemodialysis and haemodiafiltration of tryptophan and tryptophan-derived uremic toxins, indoxyl sulfate (IS) and indole acetic acid (IAA), in ESKD patients in different dialysis treatment settings. This prospective multicentre study in four European dialysis centres enrolled 78 patients with ESKD. Blood and spent dialysate samples obtained during dialysis were analysed with high-performance liquid chromatography to assess uremic solutes, their reduction ratio (RR) and total removed solute (TRS). Mean free serum tryptophan and IS concentrations increased, and concentration of IAA decreased over pre-dialysis levels (67%, 49%, -0.8%, respectively) during the first hour of dialysis. While mean serum total urea, IS and IAA concentrations decreased during dialysis (-72%, -39%, -43%, respectively), serum tryptophan levels increased, resulting in negative RR (-8%) towards the end of the dialysis session (p < 0.001), despite remarkable Trp losses in dialysate. RR and TRS values based on serum (total, free) and dialysate solute concentrations were lower for conventional low-flux dialysis (p < 0.001). High-efficiency haemodiafiltration resulted in 80% higher Trp losses than conventional low-flux dialysis, despite similar neutral Trp RR values. In conclusion, serum Trp concentrations and RR behave differently from uremic solutes IS, IAA and urea and Trp RR did not reflect dialysis Trp losses. Conventional low-flux dialysis may not adequately clear Trp-related uremic toxins while high efficiency haemodiafiltration increased Trp losses
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