Papers by Tomasz Wyszomirski
A general rule of thumb for biological conservation obtained from simple models of hypothetical s... more A general rule of thumb for biological conservation obtained from simple models of hypothetical species is that for populations with strong environmental noise moderate increases in habitat size or quality do not substantially reduce extinction risk. However, whether this rule also holds for real species with complex behavior, such as social species with breeding units and reproductive suppression, is uncertain. Here we present a population viability analysis of the alpine marmot Marmota marmota, which displays marked social behavior, i.e. it lives in social groups of up to twenty individuals. Our analysis is based on a long-term field study carried out in the Bavarian Alps since 1982. During the first fifteen years of this study, 687 marmots were individually marked and the movements and fate of 98 dispersing marmots were recorded with radio-telemetry. Thus, in contrast to most other viability analyses of spatially structured populations, good data about dispersal exist. A model was constructed which is individual-based, spatially explicit at the scale of clusters of neighbouring territories, and spatially implicit at larger scales. The decisive aspect of marmot life history, winter mortality, is described by logistic regression where mortality is increased by age and the severity of winter, and decreased by the number of subdominant individuals present in a group. Model predictions of group size distribution are in good agreement with the results of the field study. The model shows that the effect of sociality on winter mortality is very effective in buffering environmental harshness and fluctuations. This underpins theoretical results stating that the appropriate measure of the strength of environmental noise is the ratio between the variance of population growth rate and the intrinsic rate of increase. The lessons from our study for biological conservation are that simple, unstructured models may not be sufficient to assess the viability of species with complex behavioral traits, and that even moderate increases in habitat capacity may substantially reduce extinction risk even if environmental fluctuations seem high.
PLOS ONE, 2017
Background Livestock-associated Staphylococcus aureus (LA-SA) draws increasing attention due to i... more Background Livestock-associated Staphylococcus aureus (LA-SA) draws increasing attention due to its particular ability to colonize farm animals and be transmitted to people, which in turn leads to its spread in the environment. The aim of the study was to determine the dissemination of LA-SA on pig farms selected throughout Poland, characterize the population structure of identified S. aureus, and assess the prevalence of LA-SA carriage amongst farmers and veterinarians being in contact with pigs. Methods and findings The study was conducted on 123 pig farms (89 farrow-to-finish and 34 nucleus herds), located in 15 out of 16 provinces of Poland. Human and pig nasal swabs, as well as dust samples were analyzed. S. aureus was detected on 79 (64.2%) farms from 14 provinces. Amongst these farms LA-SA-positive farms dominated (71/79, 89.9%, 95% CI [81.0%, 95.5%]). The prevalence of LA-MRSA-positive farms was lower than LA-MSSA-positive (36.6% of LA-SA-positive farms, 95% CI [25.5%, 48.9%] vs. 74.6%, 95% CI [62.9%, 84.2%]). In total, 190 S. aureus isolates were identified: 72 (38%) MRSA and 118 (62%) methicillin-susceptible S. aureus (MSSA), of which 174 (92%) isolates were classified to three livestock-associated lineages: CC398 (73%), CC9 (13%), and CC30/ST433 (6%). All CC398 isolates belonged to the animal clade. Four LA-MRSA clones were detected: ST433-IVa(2B) clone (n = 8, 11%), described to the best of our knowledge for the first time, and three ST398 clones (n = 64, 89%) with the most prevalent being ST398-V(5C2&5)c, followed by ST398-V(5C2), and ST398-IVa(2B). Nasal carriage of LA-SA by pig farmers was estimated at 13.2% (38/283), CC398 carriage at 12.7% (36/283) and ST398-MRSA carriage at 3.2% (9/283), whereas by veterinarians at 21.1% (8/38), 18.4% (7/38) and 10.5% (4/38), respectively. Conclusions The prevalence of LA-MRSA-positive pig farms in Poland has increased considerably since 2008, when the first MRSA EU baseline survey was conducted in Europe. On Polish pig
Are controversies in science driven by randomness and misbeliefs?
Recent years have brought about the realisation of an irreproducibility crisis in science, which ... more Recent years have brought about the realisation of an irreproducibility crisis in science, which may have numerous causes, including common standards of statistical analysis. For decades, the methodological paradigm of null hypothesis significance testing (NHST) has remained under harsh, yet rather ineffective criticism. Here, we show that the vast majority of contradictions between the results of distinct studies may be fictitious, resulting from misbeliefs about NHST. To exemplify how they appear, we provide extensive reanalyses of results from high-profile literature and reveal statistical uncertainties that customarily remained obscured by the NHST paradigm. Widespread awareness of these uncertainties accompanied with quantitative interpretation of the results is the first step in assessing the actual scale of the irreproducibility problem and eradicating it.
Mild palmitate treatment increases mitochondrial mass but does not affect EA.hy926 endothelial cells viability
Archives of Biochemistry and Biophysics
Alleviation of Plant Stress Precedes Termination of Rich Fen Stages in Peat Profiles of Lowland Mires
Ecosystems
Plant functional traits reveal strong effects of anoxia and nutrient limitation on species pool filtering in a riverine rich fen system
Plant Ecology & Diversity
Are we restoring functional fens? – The outcomes of restoration projects in fens re-analysed with plant functional traits
PLOS ONE
No evidence of involvement of E-cadherin in cell fate specification or the segregation of Epi and PrE in mouse blastocysts
PLOS ONE
To mow or not to mow? Plant functional traits help to understand management impact on rich fen vegetation
Applied Vegetation Science
Competitive Asymmetry Reduces Spatial Effects on Size-Structure Dynamics in Plant Populations
Annals of Botany
Asymmetric competition as a natural outcome of neighbour interactions among plants: results from the field-of-neighbourhood modelling approach
Plant Ecol, 2004
Simple mechanisms of size distribution dynamics in crowded and uncrowded virtual monocultures
Ecological Modelling, 1999
Asymmetric competition as a natural outcome of neighbour interactions among plants: results from the field-of-neighbourhood modelling approach
Plant Ecol, 2004
Variation in Local Density Results in a Positive Correlation between Plant Neighbor Sizes
The American Naturalist, 2009
A positive correlation between the sizes of plants and the sizes of their nearest neighbors has b... more A positive correlation between the sizes of plants and the sizes of their nearest neighbors has been observed in many plant populations and is most often attributed to variation in microsite quality. We demonstrate another potentially important cause, using a simple spatial simulation model in which a plant's size is determined by its available area plus stochastic variation. If the spatial arrangement of individuals is nonuniform and local crowding reduces individual size, a positive correlation between the size of a plant and the size of neighboring individuals is to be expected. If a plant is small because it is crowded, its nearest neighbors will also tend to be crowded and therefore small. Such positive correlations will be observed whenever any trait of an object is related to the area available to it. Looking at the performance of neighboring objects without explicitly considering distance can give a very misleading signal.
Three Ramblers in the Normal Mountains: A Pictorial Treatise on The Best-Fit Lines
DESCRIPTION An intuition-appealing illustration of various uses of best-fit lines is presented. I... more DESCRIPTION An intuition-appealing illustration of various uses of best-fit lines is presented. It is stressed that the goal of line fitting is of primary importance and only in view of the goal one can decide which kind of line is the best. Three such goals are delimited and relations between them discussed.
Journal of Theoretical Biology, 1992
Bimodality of size distributions is often found both in plant and animal populations, but any wid... more Bimodality of size distributions is often found both in plant and animal populations, but any widely accepted measure of it does not exist. Kurtosis coefficient g2 can be, with some reservations, considered to be a measure of bimodality in symmetric distributions. Bimodality-generating mechanisms usually make distributions platykurtic. Strongly asymmetric distributions are ieptokurtic and also may remain as such when an additional mode emerges. This disqualifies kurtosis as a bimodality measure. The logarithmic transformation, which is often used to make distributions less asymmetric, may create bimodality. This leads to the concept of bimodalizable and platykurtizable distributions, i.e. distributions becoming bimodal or platykurtic, respectively, after transformation. The log-transformation is appropriate only in some cases. In this paper, the Box-Cox (BC) transformation to symmetry is proposed as a basis for assessing bimodalizability. Bimodalizable and platykurtizable distributions are defined as distributions becoming bimodai or platykurtic, respectively, after the symmetrizing BC-transformation. Further transformation by the normal cumulative distribution function allows us to present platykurtizability graphically. Kurtosis of BC-transformed data indicates the operation of bimodality-promoting mechanisms much better than the common kurtosis coefficient. Properties of the proposed procedure are illustrated by its application to distribution mixtures. Examples of its behaviour are also presented for data drawn from simulation of growth and competition in even-aged plant populations.
Simple mechanisms of size distribution dynamics in crowded and uncrowded virtual monocultures
Ecological Modelling, 1999
Size structure dynamics in even-aged monocultures sometimes exhibits fairly complex patterns. Lik... more Size structure dynamics in even-aged monocultures sometimes exhibits fairly complex patterns. Likewise, models of competition among individuals are also able to produce various changes in size distributions. This raises the question about the reliability of inferences from patterns (size distributions) to processes occurring in plant monocultures. We review some possible mechanisms of size distribution dynamics and their pure, isolated effects
European journal of medical research, Jan 4, 2010
Influenza vaccinations are recommended for health professionals by the WHO and the CDC. Medical s... more Influenza vaccinations are recommended for health professionals by the WHO and the CDC. Medical students are important health professionals not only as future physicians, but also due to their frequent contact with patients during their education. The aim of this study was to compare the knowledge, attitudes, motivations and influenza vaccinations of medicine students in three different countries: Poland, France, and Iran. 1045 self-reported questionnaires were given to medical students of Warsaw Medical University (n = 502), the Faculty of Medicine of Strasbourg University (n = 371) and Teheran University of Medical Sciences (n = 172). In France, students working in a hospital can be vaccinated free of charge. In Poland and Iran students are required to pay for the vaccine and have to arrange the administration of the vaccine on their own. Vaccination of students during the year of the study time was generally infrequent: the highest was in Strasbourg 29.7%; it was lower in Warsaw ...
BMC infectious diseases, Jan 9, 2004
Rabies is one of the most hazardous zoonoses in the world. Oral mass vaccination has developed in... more Rabies is one of the most hazardous zoonoses in the world. Oral mass vaccination has developed into the most effective management method to control fox rabies. The future need to control the disease in large countries (i.e. Eastern Europe and the Americas) forces cost-benefit discussions. The 'Increase bait density' option refers to the usual management assumption that more baits per km2 could compensate for high fox abundance and override the imperfect supply of bait pieces to the individual fox. We use a spatial simulation, which combines explicitly fox space use (tessellation polygons) and aeroplane flight lines (straight lines). The number of baits actually falling into each polygon is measured. The manager's strategic options are converted into changes of the resulting bait distribution on the ground. The comparison enables the rating of the options with respect to the management aim (i.e. accessibility of baits). Above 5% (approx. 10%) of all fox groups without any...
Plant Ecology (formerly Vegetatio), 2000
Numerous attempts have been made to infer the mode of competition from size or biomass distributi... more Numerous attempts have been made to infer the mode of competition from size or biomass distributions of plant cohorts. However, since the relationship between mode of competition and size distributions may be obscured by a variety of factors such as spatial configuration, density or resource level, empirical investigations often produce ambiguous results. Likewise, the findings of theoretical analyses of asymmetric competition are equivocal. In this paper, we analyse the mode of competition in an individual-based model which is based on the new fieldof-neighbourhood approach. In this approach, plants have a zone of influence that determines the distance up to which neighbours are influenced. Additionally, a superimposed field within the zone of influence defines phenomenologically the strength of influence of an individual on neighbouring plants. We investigated competition at both individual and population level and characterised the influence of density and of the shape of the fieldof-neighbourhood on occurrence and degree of competitive asymmetry. After finding asymmetric competition emerging in all scenarios, we argue that asymmetric competition is a natural consequence of local competition among neighbouring plants.
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Papers by Tomasz Wyszomirski