Search results for "Model"
showing 10 items of 24058 documents
Transparency reduces predator detection in mimetic clearwing butterflies
2019
International audience; Predation is an important selective pressure and some prey have evolved conspicuous warning signals that advertise unpalatability (i.e. aposematism) as an antipredator defence. Conspicuous colour patterns have been shown effective as warning signals, by promoting predator learning and memory. Unexpectedly, some butterfly species from the unpalatable tribe Ithomiini possess transparent wings, a feature rare on land but common in water, known to reduce predator detection.We tested if transparency of butterfly wings was associated with decreased detectability by predators, by comparing four butterfly species exhibiting different degrees of transparency, ranging from ful…
The Effect of Predator Population Dynamics on Batesian Mimicry Complexes.
2022
Understanding Batesian mimicry is a classic problem in evolutionary biology. In Batesian mimicry, a defended species (the model) is mimicked by an undefended species (the mimic). Prior theories have emphasized the role of predator behavior and learning as well as evolution in model-mimic complexes but have not examined the role of population dynamics in potentially governing the relative abundances and even persistence of model-mimic systems. Here, we examined the effect of the population dynamics of predators and alternative prey on the prevalence of warning-signaling prey composed of models and mimics. Using optimal foraging theory and signal detection theory, we found that the inclusion …
Diversity in warning coloration: selective paradox or the norm?
2019
Aposematic theory has historically predicted that predators should select for warning signals to converge on a single form, as a result of frequency-dependent learning. However, widespread variation in warning signals is observed across closely related species, populations and, most problematically for evolutionary biologists, among individuals in the same population. Recent research has yielded an increased awareness of this diversity, challenging the paradigm of signal monomorphy in aposematic animals. Here we provide a comprehensive synthesis of these disparate lines of investigation, identifying within them three broad classes of explanation for variation in aposematic warning signals: …
Características de los vecindarios y la distribución espacial de problemas sociales en la ciudad de Valencia
2018
The aim of this doctoral thesis is to explore the influence of neighborhood-level variables on the spatial and spatio-temporal distribution of different social problems in the city of Valencia. In Study 1, we present data on the development and validation of an observational instrument to assess neighborhood disorder. Results supported a three-factor model (physical disorder, social disorder and physical deterioration), and they showed good reliability and validity evidences. In Study 2, we assess the psychometric properties of a neighborhood disorder scale using Google Street View. Results supported a bifactorial solution with a general factor (general neighborhood disorder) and two specif…
Assessing Transfer Entropy in cardiovascular and respiratory time series: A VARFI approach
2021
In the study of complex biomedical systems represented by multivariate stochastic processes, such as the cardiovascular and respiratory systems, an issue of great relevance is the description of the system dynamics spanning multiple temporal scales. Recently, the quantification of multiscale complexity based on linear parametric models, incorporating autoregressive coefficients and fractional integration, encompassing short term dynamics and long-range correlations, was extended to multivariate time series. Within this Vector AutoRegressive Fractionally Integrated (VARFI) framework formalized for Gaussian processes, in this work we propose to estimate the Transfer Entropy, or equivalently G…
Vecuma ietekme uz Farnsworth D15 testa rezultātiem
2020
Bakalaura darbs ir uzrakstīts latviešu valodā uz 28 lapām. Tajā ir 24 attēli, 4 tabulas, 27 literatūras avoti. Darba mērķis: noskaidrot, vai izmantojot matemātisko modeli var paredzēt krāsu kauliņu sakārtošanas secības dažādu vecumu grupu pārstāvjiem bez krāsu redzes deficītiem. Metode: darbojoties ar matemātisko modeli, tika mainīts cilvēka vecums un noteikts krāsu kauliņu sakārtošanas secība Farnsworth D-15 testam. Rezultāti: matemātiskais modelis piefiksēja pirmas izmaiņas krāsu kauliņu sakārtošanas secībā 110 gadus vecam cilvēkam un konfūzijas lēņķis Vingrys & KingSmith metodē, kas ir vienāds ar -48,31°, norāda uz tritānam līdzīgo deficītu. Secinājumi: izmantojot matemātisko modeli var …
Vecāku atbildība pamatskolas izglītībā Latvijā
2022
Maģistra darba tēma: “Vecāku atbildība pamatskolas izglītībā” šobrīd ir ļoti aktuāla problēma, ievērojot skolēnu nepiemēroto rīcību mācību iestādēs. Pedagogi bieži sūdzas par emocionālo un fizisko vardarbību no skolēnu un vecāku puses. Presē aizvien biežāk tiek atspoguļoti starpgadījumi, kuros skolotāji cietuši no vardarbības. Maģistra darba pētījuma jautājums: kāda ir vecāku atbildība pamatskolas izglītībā Latvijā. Lai rastu atbildes uz šo jautājumu, tika veikta anketēšana, kuru analizējot tās tika meklētas. Vecāku atbildība ir subjektīvs jēdziens, kura nozīme katrai izglītības iestādei var atšķirties, gan atbilstoši izstrādātajiem skolas iekšējiem normatīvajiem aktiem, gan atkarībā no izg…
Model organisms and their application in environmental epigenetics
2020
Abstract Epigenetic mechanisms operate at the interface between the environment and the genome of a given organism. More particularly, they convert environmental stimuli as diverse as chemical pollutants, nutritional components, temperature changes, and social conditions into changes in the chromatin landscape, which influence gene expression in the absence of alterations in the DNA sequence, ultimately leading to phenotype adaptation and diversification. The use of experimental model organisms in epigenetics research allows for the careful manipulation of environmental factors in order to understand how they mechanistically modulate the establishment, maintenance, and inheritance of epigen…
Author Correction: Evaluation of three methods for biomass estimation in small invertebrates, using three large disparate parasite species as model o…
2018
Invertebrate biomass is considered one of the main factors driving processes in ecosystems. It can be measured directly, primarily by weighing individuals, but more often indirect estimators are used. We developed two indirect and non-destructive approaches to estimate biomass of small invertebrates in a simple manner. The first one was based on clay modelling and the second one was based on image analysis implemented with open-source software. Furthermore, we tested the accuracy of the widely used geometric approximation method (third method). We applied these three different methods to three morphologically disparate model species, an acanthocephalan worm, a crustacean and a flatworm. To …
The Developmental Transcriptome for Lytechinus variegatus Exhibits Temporally Punctuated Gene Expression Changes
2019
AbstractEmbryonic development is arguably the most complex process an organism undergoes during its lifetime, and understanding this complexity is best approached with a systems-level perspective. The sea urchin has become a highly valuable model organism for understanding developmental specification, morphogenesis, and evolution. As a non-chordate deuterostome, the sea urchin occupies an important evolutionary niche between protostomes and vertebrates.Lytechinus variegatus(Lv) is an Atlantic species that has been well studied, and which has provided important insights into signal transduction, patterning, and morphogenetic changes during embryonic and larval development. The Pacific specie…