Search results for "evolution"
showing 10 items of 11096 documents
Quantitative Prediction of the Landscape of T Cell Epitope Immunogenicity in Sequence Space
2019
Immunodominant T cell epitopes preferentially targeted in multiple individuals are the critical element of successful vaccines and targeted immunotherapies. However, the underlying principles of this "convergence" of adaptive immunity among different individuals remain poorly understood. To quantitatively describe epitope immunogenicity, here we propose a supervised machine learning framework generating probabilistic estimates of immunogenicity, termed "immunogenicity scores," based on the numerical features computed through sequence-based simulation approximating the molecular scanning process of peptides presented onto major histocompatibility complex (MHC) by the human T cell receptor (T…
Evolucionismo, integración sociocognitiva y cambio semántico
2014
El cambio es el fenómeno lingüístico por excelencia a la hora de aplicar los modelos teóricos evolucionistas. La perspectiva evolucionista del lenguaje permite analizar el cambio lingüístico como un fenómeno sujeto a los mismos procesos evolutivos que determinan cualquier sistema evolutivo complejo. El objetivo de este estudio es defender una integración más sistemática de los factores sociales y cognitivos del cambio lingüístico, en particular del cambio semántico. Este artículo se centra en un enfoque evolutivo del cambio lingüístico muy influyente, la Teoría de la Selección del Enunciado del cambio lingüístico desarrollada por Croft (2000). El enfoque evolutivo de Croft se inspira en la …
Analogia e omologia: la questione della filogenesi delle emozioni
2013
Aim of this paper is to outline a new evolutionary interpretation of aesthetic emotions, in the light of the most recent developments in Evolutionary Biology, in particular the so-called “Extended Synthesis of Evolution” (Pigliucci-Müller 2010). Focussing on the biological concept of homology, the Author argues that, in order to effectively understand role and evolutionary value of aesthetic emotions, it should be asked not “what aesthetic emotions are for?”, rather “what kind of constraints and homologies influence the specific “shape” of human aesthetic emotions?”. In a few words, we should move from a functionalist approach to human aesthetic emotions towards a morphological one.
Exponentiating derivations of quasi∗-algebras: possible approaches and applications
2005
The problem of exponentiating derivations of quasi∗-algebras is considered in view of applying it to the determination of the time evolution of a physical system. The particular case where observables constitute a properCQ∗-algebra is analyzed.
Bacterial and phytoplankton responses to nutrient amendments in a boreal lake differ according to season and to taxonomic resolution
2011
Nutrient limitation and resource competition in bacterial and phytoplankton communities may appear different when considering different levels of taxonomic resolution. Nutrient amendment experiments conducted in a boreal lake on three occasions during one open water season revealed complex responses in overall bacterioplankton and phytoplankton abundance and biovolume. In general, bacteria were dominant in spring, while phytoplankton was clearly the predominant group in autumn. Seasonal differences in the community composition of bacteria and phytoplankton were mainly related to changes in observed taxa, while the differences across nutrient treatments within an experiment were due to chang…
Phenotypic Buffering in a Monogenean: Canalization and Developmental Stability in Shape and Size of the Haptoral Anchors of Ligophorus cephali (Monog…
2015
Phenotypic variation results from the balance between sources of variation and counteracting regulatory mechanisms. Canalization and developmental stability are two such mechanisms, acting at two different levels of regulation. The issue of whether or not they act concurrently as a common developmental buffering capacity has been subject to debate. We used geometric morphometrics to quantify the mechanisms that guarantee phenotypic constancy in the haptoral anchors of Ligophorus cephali. Canalization and developmental stability were appraised by estimating inter- and intra-individual variation, respectively, in size and shape of dorsal and ventral anchors. The latter variation was estimated…
A Combined Multi-Cohort Approach Reveals Novel and Known Genome-Wide Selection Signatures for Wool Traits in Merino and Merino-Derived Sheep Breeds.
2019
Merino sheep represents a valuable genetic resource worldwide. In this study, we investigated selection signatures in Merino (and Merino-derived) sheep breeds using genome-wide SNP data and two different approaches: a classical F-ST-outlier method and an approach based on the analysis of local ancestry in admixed populations. In order to capture the most reliable signals, we adopted a combined, multi-cohort approach. In particular, scenarios involving four Merino breeds (Spanish Merino, Australian Merino, Chinese Merino, and Sopravissana) were tested via the local ancestry approach, while nine pair-wise breed comparisons contrasting the above breeds, as well as the Gentile di Puglia breed, …
Pole-to-Pole Connections: Similarities between Arctic and Antarctic Microbiomes and Their Vulnerability to Environmental Change
2017
The global biogeography of microorganisms remains poorly resolved, which limits the current understanding of microbial resilience toward environmental changes. Using high-throughput 16S rRNA gene amplicon sequencing, we characterized the microbial diversity of terrestrial and lacustrine biofilms from the Arctic, Antarctic and temperate regions. Our analyses suggest that bacterial community compositions at the poles are more similar to each other than they are to geographically closer temperate habitats, with 32% of all operational taxonomic units (OTUs) co-occurring in both polar regions. While specific microbial taxa were confined to distinct regions, representing potentially endemic popul…
Erratum for Piwosz et al., "Light and Primary Production Shape Bacterial Activity and Community Composition of Aerobic Anoxygenic Phototrophic Bacter…
2020
Metabolic coupling between phytoplankton and bacteria determines the fate of dissolved organic carbon in aquatic environments, and yet how changes in the rate of primary production affect the bacterial activity and community composition remains understudied. Here, we experimentally limited the rate of primary production either by lowering light intensity or by adding a photosynthesis inhibitor. The induced decrease had a greater influence on bacterial respiration than on bacterial production and growth rate, especially at an optimal light intensity. This suggests that changes in primary production drive bacterial activity, but the effect on carbon flow may be mitigated by increased bacteria…
Distribution and depletion of sulfadiazine after a multiple per os dosing in gilthead sea bream (Sparus aurata) fed two different diets
2013
The distribution and depletion profile of sulfadiazine (SDZ) were investigated in gilthead sea bream (Sparus aurata) fed on fish oil (FO) or plant oil-based (PO) diets. Fish averaging 230 g were given medicated feed containing 25 mg SDZ kg-1 fish for 5 days at 24-26°C. Blood and muscle plus skin were sampled on days 1, 3, 5, 6, 8 and 9. Differences in plasma and fillet SDZ levels between the two groups were statistically insignificant. The maximum drug concentrations in plasma were 3.2 ± 1.9 μg mL-1 and 2.9 ± 1.2 μg mL-1 in the PO and FO groups, respectively. In post-medicated samples depletion rapidly reached concentrations close to the level of quantification at 72 h post medication. With…