20 research outputs found
A systematic investigation of candidate high-redshift galaxies in JWST deep fields
openThanks to the deep JWST survey carried in the SMACS 0723 cluster, there has been
the discovery of an interesting population of objects not observed by the previous
optical telescope, such as HST, and whose nature is still under investigation. The
aim of this work is to compare the physical parameters obtained through the spectral
energy distribution modelling technique applied on a sample of 19 galaxies present
in this field, chosen for their very red near-infrared colours, being undetected at
λobs < 2Όm. Aiming to provide an accurate systematic investigation, the photometric
analysis of these sources has been carried out through several software tools. Hence,
this work intends to find discrepancies among the results obtained through the
different photometric analysis, confronting the outputs obtained, as well as to check
their consistency, in order to understand how much the choice of the technique can
influence the results and therefore our understanding of the nature of high-redshift
galaxies properties. In a future perspective, this kind of investigation can be
enlarged adding various others photometric databases of deep JWST surveys, along
with considering alternative tools for both photometric analysis and spectral energy
distribution fitting
Il contenuto di materia oscura di Galassie a disco nell'epoca di picco della formazione stellare.
Testing for changes in rate of evolution and position of the climatic niche of clades
1. There is solid recognition that phylogenetic effects must be acknowledged to appreciate climatic niche variability among species clades properly. Yet, most currently available methods either work at the intra- specific level (hence they ignore phylogeny) or rely on the Brownian motion model of evolution to estimate phylogenetic effects on climatic niche variation. The Brownian mo-tion model may be inappropriate to describe niche evolution in several cases, and even a significant phylogenetic signal in climatic variables does not in-dicate that the effect of shared ancestry was relevant to niche evolution.2. We introduce a new phylogenetic comparative method which describes sig-nificant changes in the width and position of the climatic niche at the inter-specific (clade) level, while making no a priori assumption about how niche evolution took place.3. We devised the R function phylo.niche.shift to estimate whether the climatic niches of individual clades in the tree are either wider or narrower than expected, and whether the niche occupies unexpected climates. We tested phylo.niche.shift on realistic virtual speciesâ distribution patterns applied to a phylogeny of 365 extant primate species.4. We demonstrate via simulations that the new method is fast and accurate under widely different climatic niche evolution scenarios. phylo.niche.shift showed that the capuchin monkeys and langurs occupy much wider, and prosimian much narrower, climatic niche space than expected by their phylogenetic positions.5. phylo.niche.shift may help to improve research on niche evolution by allow-ing researchers to test specific hypotheses on the factors affecting cladesâ realised niche width and position, and the potential effects of climate change on speciesâ distribution
Between but not within species variation in the distribution of fitness effects
New mutations provide the raw material for evolution and adaptation. The distribution of fitness effects (DFE) describes the spectrum of effects of new mutations that can occur along a genome, and is therefore of vital interest in evolutionary biology. Recent work has uncovered striking similarities in the DFE between closely related species, prompting us to ask whether there is variation in the DFE among populations of the same species, or among species with different degrees of divergence, i.e., whether there is variation in the DFE at different levels of evolution. Using exome capture data from six tree species sampled across Europe we characterised the DFE for multiple species, and for each species, multiple populations, and investigated the factors potentially influencing the DFE, such as demography, population divergence and genetic background. We find statistical support for there being variation in the DFE at the species level, even among relatively closely related species. However, we find very little difference at the population level, suggesting that differences in the DFE are primarily driven by deep features of species biology, and that evolutionarily recent events, such as demographic changes and local adaptation, have little impact
Neurological soft signs: significato e rilevanza nel corso della patologia psichiatrica. Uno screening obiettivo veloce per psicosi?
I neurological soft signs (NSS) sono âlieviâ anomalie neurologiche, indicative di una diffusa disfunzione
del sistema nervoso centrale. Molti sono stati gli studi condotti sullâargomento e sarĂ pertanto utile fare il punto sulle attuali
conoscenze, in modo da poter definire il reale ruolo dei NSS nella patologia psichiatrica e, di conseguenza, la loro utilitĂ
clinica. Metodo. Sono stati selezionati tutti i lavori incentrati sulle relazioni esistenti tra NSS e principali disturbi psichiatrici
e sulle correlazioni esistenti con la terapia antipsicotica. Risultati. Molte sono le dimostrazioni cliniche sulle correlazioni
esistenti tra NSS e schizofrenia; minori, ma comunque significative sulle correlazioni con il disturbo ossessivo-compulsivo
e con il disturbo bipolare. In tutte queste tre popolazioni psichiatriche si evidenzia come la prevalenza di NSS sia significativamente superiore rispetto alla popolazione generale e di come sia possibile riscontrare manifestazioni neurologiche giĂ allâesordio della malattia. Ă stato inoltre dimostrato come i NSS siano spesso in stretta correlazione con elementi psicopatologici,
tanto da poter essere considerati indicatori di gravitĂ del disturbo, severitĂ del decorso e non ultima, risposta terapeutica.
Questi risultati non sembrano essere in relazione con il trattamento farmacologico. Conclusioni. I NSS risultano essere
un elemento clinico obiettivo nella valutazione di disturbi psichiatrici gravi, sia in una fase prodromica, permettendo di ipotizzare un maggior rischio di sviluppo di malattia e quindi possibilitĂ di un intervento precoce, sia allâesordio, in quanto spesso elemento predittivo di gravitĂ e risposta terapeutica, sia durante il decorso della malattia, in quanto direttamente correlati
alla sintomatologia psichiatrica legata a processi ideativi piĂč complessi
Physico-Chemical, Electrochemical and Structural Insights Into Poly(3,4-ethylenedioxythiophene) Grafted from Molecularly Engineered Multi-Walled Carbon Nanotube Surfaces
Composites of multi-walled carbon nanotubes (MWCNTs) and poly(3,4-ethylenedioxythiophene) (PEDOT) are attracting the attention of material scientists since more than a decade as potential next-generation optoelectronic materials for their peculiar features, arising from the combination of the intrinsic electrical, thermal and morphological properties of the two components. They are indeed a promising platform for the development of low-cost, portable and environmentally friendly electronic devices such as supercapacitors, sensors and actuators. Here a novel synthetic strategy for their preparation is envisaged, exploiting the possibility to covalently functionalize the external surface of MWCNTs with tailored molecular units, starting from which the growth of the conjugated polymer can be induced oxidatively. The approach demonstrates its value in being able to effectively promote the formation of PEDOT chains in direct contact with the surface of MWCNTs, differently from what results when the monomer is polymerized in the presence of the pristine carbon nanomaterial. In addition, significant differences are found in the physico-chemical properties and electrochemical behavior when MWCNT-PEDOT covalent composites are studied in comparison to a non-covalent analogue, here illustrated in detail. These evidences constitute a starting point for the future development of novel more finely tuned functional materials based on MWCNT-PEDOT composites, featuring the required optoelectronic properties to precisely target the desired application
Risperidone-induced leukopenia: a case report and brief review of literature
A Caucasian, male, young adult with recurrent agitated depression and suicidal ideation received lithium and oral olanzapine. His white blood cell count was normal at that time. Due to unsatisfactory response, he received 4 mg/day risperidone. While symptoms improved, leukopenia emerged, specifically directed towards neutrophils. Upon risperidone discontinuation, white blood cell count returned to reference values within 1 week. As symptom control was satisfactory, we attempted no risperidone rechallenge. Accurate blood testing must accompany atypical antipsychotic drug administration since blood dyscrasias are always possible with these drugs. (C) 2013 Elsevier Inc. All rights reserved
Trends of use of typical antipsychotic drugs in a population of bipolar patients followed in community national mental health clinics
One among many: the enigmatic case of the Miocene mammal, Kolponomos newportensis
Kolponomos newportensis is an enigmatic Miocene mammal allied to stem Pinnipedimorpha. It has been suggested that Kolponomos fed on hard-shelled benthic marine invertebrates by using its mandible as a wedge to dislodge its prey from the sea bottom by means of strong pull and torque forces. This unique feeding style was thought to originate from a singular case of mosaic convergence in mandible biomechanics between Kolponomos and the sabretoothed cat Smilodon, which complied with similarly strong torque forces when grappling with prey. As such forces must have reflected on the cranium as well, we hypothesize that the convergence between Kolponomos and the sabretoothed cats could have affected its shape. To test this hypothesis, we looked for patterns of morphological convergence in cranial shape between Kolponomos and sabretoothed cats. We found that Kolponomos is not distinctly closer to Smilodon than a number of other pinnipeds. Yet, local areas of shape convergence with Smilodon are observed in the canine area and the posterior part of the cranium, that is where the bite applies and the temporalis muscle is located, respectively. These results indicate that the mosaic convergence present between the mandibles of Kolponomos and Smilodon is partially reflected in the cranium as well
ENphylo: A new method to model the distribution of extremely rare species
Abstract Species distribution models (SDMs) are a useful mean to understand how environmental variation influences species geographical distribution. SDMs are implemented by several different algorithms. Unfortunately, these algorithms consistently lose accuracy exactly when they are needed the most, that is with rare species, originating the so-called rare-species modelling paradox. Although approaches exist to tackle this problem, most notably by performing and then averaging a number of bivariate models, they are usually computationally intensive and were never shown to apply successfully to the rarest species (i.e. with less than 20 geographical occurrences). Here, we present a new algorithm, ENphylo, embedded in the readily-available R package RRdtn, which couples Environmental Niche Factor Analysis (ENFA) and phylogenetic imputation to model the distribution of rare species. Using the fossil record of 31 species of large mammals that lived during the late Pleistocene as the source data to sample from, we demonstrate ENphylo provides good SDM evaluation scores, with area under the curve and S?rensen Index both consistently above 0.75, True Skills Statistics above 0.4 and Boyce Index above 0.5 in most cases, when just 10 fossil occurrences are randomly drawn from their respective fossil records. ENphylo proved significantly more accurate than ENFA and the ensemble of bivariate models using Maxent, Generalized Linear Model and Random Forest algorithms. Intriguingly, we found that randomly drawing as little as 10 occurrence data points per species allows ENphylo to perform equally well as Maxent run using the entire fossil record of these same species and data. ENphylo provides a fast and accurate solution to perform species distribution modelling with rare species, which will help predicting their distribution in the light of climate change, and to delineate how rare extinct species reacted to past climatic variation