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showing 10 items of 2270 documents
Genetic structure of a patchily distributed philopatric migrant: implications for management and conservation
2017
Significant demographic fluctuations can have major genetic consequences in wild populations. The lesser kestrel (Falco naumanni) has suffered both population declines and range fragmentation during the second half of the 20th century. In this study we analysed multilocus microsatellite data to assess the genetic structure of the species. Our analysis revealed significant genetic structuring of lesser kestrel populations, not only at the cross-continental scale, but also regionally within the Central and Eastern (CE) Mediterranean region. We detected signs of genetic bottlenecks in some of the peripheral populations coupled with small effective population sizes. Values of genetic differenti…
Extinction risk under coloured environmental noise
2000
Positively autocorrelated red environmental noise is characterized by a strong dependence of expected sample variance on sample length. This dependence has to be taken into account when assessing extinction risk under red and white uncorrelated environmental noise. To facilitate a comparison between red and white noise, their expected variances can be scaled to be equal, but only at a chosen time scale. We show with a simple one-dimensional population dynamics model that the different but equally reasonable choices of the time scale yield qualitatively different results on the dependence of extinction risk on the colour of environmental noise: extinction risk might increase as well as decre…
Environment-sensitivity functions for gross primary productivity in light use efficiency models
2022
International audience; The sensitivity of photosynthesis to environmental changes is essential for understanding carbon cycle responses to global climate change and for the development of modeling approaches that explains its spatial and temporal variability. We collected a large variety of published sensitivity functions of gross primary productivity (GPP) to different forcing variables to assess the response of GPP to environmental factors. These include the responses of GPP to temperature; vapor pressure deficit, some of which include the response to atmospheric CO2 concentrations; soil water availability (W); light intensity; and cloudiness. These functions were combined in a full fact…
The Bias of combining variables on fish's aggressive behavior studies.
2019
Made available in DSpace on 2019-10-06T16:27:42Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-07-01 Quantifying animal aggressive behavior by behavioral units, either displays or attacks, is a common practice in animal behavior studies. However, this practice can generate a bias in data analysis, especially when the variables have different temporal patterns. This study aims to use Bayesian Hierarchical Linear Models (B-HLMs) to analyze the feasibility of pooling the aggressive behavior variables of four cichlids species. Additionally, this paper discusses the feasibility of combining variables by examining the usage of different sample sizes and family distributions to aggressive …
Benchmark database for fine-grained image classification of benthic macroinvertebrates
2018
Managing the water quality of freshwaters is a crucial task worldwide. One of the most used methods to biomonitor water quality is to sample benthic macroinvertebrate communities, in particular to examine the presence and proportion of certain species. This paper presents a benchmark database for automatic visual classification methods to evaluate their ability for distinguishing visually similar categories of aquatic macroinvertebrate taxa. We make publicly available a new database, containing 64 types of freshwater macroinvertebrates, ranging in number of images per category from 7 to 577. The database is divided into three datasets, varying in number of categories (64, 29, and 9 categori…
Green methodology for quality control of elemental content of infant milk powder
2019
Abstract A green methodology for the direct determination of elemental content in infant milk powder samples from 0 to 3 years was developed. A portable energy dispersive X-ray fluorescence (ED-XRF) tool has been used as a direct method for the quantification of five essential elements (Ca, K, Fe, Cu and Zn). For analysis pellets from 0.8 g of each sample weight were made and analyzed. Due to the high dependence of the ED-XRF signal with the sample matrix, external calibrations using cocoa powder diluted with glucose were performed. Infant milk samples were diluted with lactose and the signals were interpolated in the external calibrations. Concentrations obtained by ED-XRF were compared wi…
Discrimination of fish populations using parasites: Random Forests on a ‘predictable’ host-parasite system
2010
SUMMARYWe address the effect of spatial scale and temporal variation on model generality when forming predictive models for fish assignment using a new data mining approach, Random Forests (RF), to variable biological markers (parasite community data). Models were implemented for a fish host-parasite system sampled along the Mediterranean and Atlantic coasts of Spain and were validated using independent datasets. We considered 2 basic classification problems in evaluating the importance of variations in parasite infracommunities for assignment of individual fish to their populations of origin: multiclass (2–5 population models, using 2 seasonal replicates from each of the populations) and 2…
Chasing phthalates in tissues of marine turtles from the Mediterranean sea
2018
Tissues from thirteen specimens of marine turtles, one Dermochelys coriacea and twelve Caretta caretta, found dead along the Sicilian coasts in 2016 were analyzed for the presence of phthalates. Four phthalates (DEP, DBP, BBP, and DEHP) were found at different significant concentrations in liver and gonads, while only DBP was found in muscle tissues and at a fourfold lower concentration than other phthalates in Dermochelys coriacea. No traces of DEP were detected in C. caretta tissues where DOTP was also revealed. The presence of phthalates in fat tissue in specimens of C. caretta showed a major prevalence of the most lipophilic phthalates DEHP and DOTP. The total concentration of all analy…
Bayesian analysis improves experimental studies about temporal patterning of aggression in fish.
2017
Made available in DSpace on 2018-12-11T17:15:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-12-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) This study aims to describe a Bayesian Hierarchical Linear Model (HLM) approach for longitudinal designs in fish's experimental aggressive behavior studies as an alternative to classical methods In particular, we discuss the advantages of Bayesian analysis in dealing with combined variables, non-statistically significant results and required sample size using an experiment of angelfish (Pterophyllum scalare) species as case study. Groups of 3 individuals were subjected to daily observations recorded for 10 min durin…
Survey on the presence of non-dioxine-like PCBs (NDL-PCBs) in loggerhead turtles (Caretta caretta) stranded in south Mediterranean coasts (Sicily, So…
2017
A total of 71 loggerhead turtles (Caretta caretta) stranded along the coasts of Sicily (Southern Italy) were examined for non-dioxine like polychlorinated biphenyl (NDL-PCB) levels in muscle and adipose tissue by a gas chromatography-mass spectrometry/mass spectrometry (GC-MS/MS) method. The results revealed 6 high-indicator congener (∑6 PCBIND ) levels in 45% of the loggerhead turtles examined, with mean values of 980.39 ± 2508.39 ng/g wet weight in adipose tissue and 102.53 ± 238.58 ng/g wet weight in muscle tissue. The hexachloro and heptachloro PCB congeners were the most abundant in both the sample types. The highest NDL-PCB levels were reached in an adipose tissue sample of a loggerhe…