3,074 research outputs found
Increased tolerance to humans among disturbed wildlife.
Human disturbance drives the decline of many species, both directly and indirectly. Nonetheless, some species do particularly well around humans. One mechanism that may explain coexistence is the degree to which a species tolerates human disturbance. Here we provide a comprehensive meta-analysis of birds, mammals and lizards to investigate species tolerance of human disturbance and explore the drivers of this tolerance in birds. We find that, overall, disturbed populations of the three major taxa are more tolerant of human disturbance than less disturbed populations. The best predictors of the direction and magnitude of bird tolerance of human disturbance are the type of disturbed area (urbanized birds are more tolerant than rural or suburban populations) and body mass (large birds are more tolerant than small birds). By identifying specific features associated with tolerance, these results guide evidence-based conservation strategies to predict and manage the impacts of increasing human disturbance on birds
How Similar Are They?
Funding: Fundação para a Ciência e Tecnologia (FCT) Grant PTDC/BIABID/29663/2017 to DC, and ERC (H2020-ERC-2017-STG-GA 759853-StemCellHabitat); Wellcome Trust and Howard Hughes Medical Institute (HHMI-208581/Z/17/Z-Metabolic Reg SC fate); EMBO (H2020-EMBO-3311/2017/G2017), and FCT grant IF/01265/2014/CP1252/CT0004 to CH.Proneural genes were initially identified in Drosophila, where pioneer work on these important regulators of neural development was performed, and from which the term proneural function was coined. Subsequently, their counterparts in vertebrates were identified, and their function in neural development extensively characterized. The function of proneural transcription factors in flies and vertebrates is, however, very distinct. In flies, proneural genes play an early role in neural induction, by endowing neural competence to ectodermal cells. In contrast, vertebrate proneural genes are expressed only after neural specification, in neural stem and progenitor cells, where they play key regulatory functions in quiescence, proliferation, and neuronal differentiation. An exception to this scenario is the Drosophila proneural gene asense, which has a late onset of expression in neural stem cells of the developing embryo and larvae, similar to its vertebrate counterparts. Although the role of Asense remains poorly investigated, its expression pattern is suggestive of functions more in line with those of vertebrate proneural genes. Here, we revise our current understanding of the multiple activities of Asense and of its closest vertebrate homologue Ascl1 in neural stem/progenitor cell biology, and discuss possible parallels between the two transcription factors in neurogenesis regulation.publishersversionpublishe
Comparação de limas ProFile GT Série X com ProFile GT através da caracterização por DRX e de um Estudo por Elementos Finitos
The emergence of NiTi alloys and the development of their properties, namely superelasticity, motivated the inclusion of such materials in files used in the clinical practice of Endodontics. These files present several advantages when compared to Stainless Steel files (still widely used today), especially their larger flexibility, whereby the improvement of these alloys over the last few years has deserved a growing attention by both the medical industry and medical community. Flexibility in endodontic files is paramount for the preparation of anatomically complex root canals, since it preserves the dental structure, limits the apical transport, reduces the risk of iatrogenic mistakes and allows the irrigant to flow and reach the apical foramen. Flexibility in NiTi files due to their superelastic behaviour mainly dependends not only on the crystallographic phases present in the alloy and the thermal, mechanical and chemical treatments to which the alloy has been subjected but also due to files’ geometry. Recently, the market has seen introduced the M-Wire, a NiTi alloy used in GTX files that, according to its manufacturer, has been treated in order to have a larger flexibility at body temperature than files built with conventional NiTi wire, for instance the one used in GT files. This study aims at contributing to the better understanding of the mechanisms behind the properties each kind of file presents and to find out supporting grounds that substantiate the manufacturer pretension, through the metallurgic characterization of GT and GTX files by X-Ray Diffraction (XRD) and through finite element models of the files under bending. Some experimental results are presented and discussed, being shown that, at body temperature, the GTX files accuse the presence of R Phase, contrary to the GT files, being their geometry very alike; as such, they are expected to be more flexible and clinically superior
Transcriptional control of vertebrate neurogenesis by the proneural factor Ascl1
Proneural transcription factors (TFs) such as Ascl1 function as master regulators of neurogenesis in vertebrates, being both necessary and sufficient for the activation of a full program of neuronal differentiation. Novel insights into the dynamics of Ascl1 expression at the cellular level, combined with the progressive characterization of its transcriptional program, have expanded the classical view of Ascl1 as a differentiation factor in neurogenesis. These advances resulted in a new model, whereby Ascl1 promotes sequentially the proliferation and differentiation of neural/stem progenitor cells. The multiple activities of Ascl1 are associated with the activation of distinct direct targets at progressive stages along the neuronal lineage. How this temporal pattern is established is poorly understood. Two modes of Ascl1 expression recently described (oscillatory vs. sustained) are likely to be of importance, together with additional mechanistic determinants such as the chromatin landscape and other transcriptional pathways. Here we revise these latest findings, and discuss their implications to the gene regulatory functions of Ascl1 during neurogenesis.FCT grants: (PTDC/SAU-BID/117418/2010, PTDC/NEU-NMC/0315/2012), Marie Curie CIG, FCT fellowships: (SFRH/BD/51178/2010, IF/00413/2012)
Evidence for reduced magnetic braking in polars from binary population models
We present the first population synthesis of synchronous magnetic cataclysmic variables, called polars, taking into account the effect of the white dwarf (WD) magnetic field on angular momentum loss. We implemented the reduced magnetic braking (MB) model proposed by Li, Wu & Wickramasinghe into the Binary Stellar Evolution (BSE) code recently calibrated for cataclysmic variable (CV) evolution. We then compared separately our predictions for polars and non-magnetic CVs with a large and homogeneous sample of observed CVs from the Sloan Digital Sky Survey. We found that the predicted orbital period distributions and space densities agree with the observations if period bouncers are excluded. For polars, we also find agreement between predicted and observed mass transfer rates, while the mass transfer rates of non-magnetic CVs with periods ≳3 h drastically disagree with those derived from observations. Our results provide strong evidence that the reduced MB model for the evolution of highly magnetized accreting WDs can explain the observed properties of polars. The remaining main issues in our understanding of CV evolution are the origin of the large number of highly magnetic WDs, the large scatter of the observed mass transfer rates for non-magnetic systems with periods ≳3 h, and the absence of period bouncers in observed samples
Can neutrino-assisted early dark energy models ameliorate the tension in a natural way?
The idea of neutrino-assisted early dark energy (EDE), where a coupling
between neutrinos and the scalar field that models early dark energy (EDE) is
considered, was introduced with the aim of reducing some of the fine-tuning and
coincidence problems that appear in usual EDE models. In order to be relevant
in ameliorating the tension, the contribution of EDE to the total energy
density () should be around 10\% near the redshift of
matter-radiation equality. We verify under which conditions EDE models can
fulfill these requirements for a model with a quartic self-coupling of the EDE
field and an exponential coupling to neutrinos. We find that in the situation
where the EDE field is frozen initially, the contribution to can
be significant but it is not sensitive to the neutrino-EDE coupling and does
not address the EDE coincidence problem. On the other hand, if the EDE field
starts already dynamical at the minimum of the effective potential, it tracks
this time-dependent minimum that presents a feature triggered by the neutrino
transition from relativistic to nonrelativistic particles. This feature
generates in a natural way at around this transition epoch, that
roughly coincides with the matter-radiation equality redshift. For the set of
parameters that we considered we did not find values that satisfy the
requirements on the background cosmological evolution to mitigate the Hubble
tension in a natural way in this particular EDE model.Comment: 6 pages, 4 figures. New version with more detailed analysi
Things you need to know if you are writing a scientific paper, thesis or report in Engineering or Science
This paper focuses on the common mistakes made by students at the early stages of research when
writing scientific papers, thesis and reports. It points out mistakes to be avoided and the basic rules
that can be inferred by reading a few scientific documents but are not usually clearly written and that
we, as professors, end up teaching over and over again. The outcome of this paper will be, hopefully,
that we will not need to correct the same common mistakes again and you, as a student, will have a
faster lane to publishing. Starting with the abstract: it is composed of a single paragraph, does not
contain acronyms or references and describes in short the work, main highlights and points out the
results or main conclusions obtained from the work being presented. The abstract is an independent
part of the paper and commonly has a character or word limit that you need to respect. It can be read
as a “stand-alone” and the paper starts in the introduction, meaning that the introduction is not the
sequence of the abstract and it can have some text in common if needed.info:eu-repo/semantics/publishedVersio
Local Adaptive Receptive Field Self-Organizing Map for Image Segmentation
A new self-organizing map with variable topology is introduced for image segmentation. The proposed network, called Local Adaptive Receptive Field Self-Organizing Map (LARFSOM-RBF), is a two-stage network capable of both color and border segment images. The color segmentation stage is responsibility of LARFSOM which is characterized by adaptive number of nodes, fast convergence and variable topology. For border segmentation RBF nodes are included to determine the border pixels using previously learned information of LARFSOM. LARFSOM-RBF was tested to segment images with different degrees of complexity showing promising results
Applying pen pressure, tilt and touch interactions to data visualizations
Bimanual interactions using pen and touch are natural to humans
and have proven and explored in previous research. However, most
of the previous work has been limited to using cartesian coordinates
of fingers and pen tip. In this work, we go further by exploring
additional pen data, like pressure and tilt, combined with multi touch inputs. We apply this combination to two data visualizations:
Bubble Chart and Linear Regression combined with a Radar. We
have performed a preliminary user study comparing Pen and Touch
interactions with Mouse input. We have found the Pen and Touch
interactions can consume less time while looking for specific values
in the Bubble Chart, whereas Mouse can be faster while looking
for specific relation in Linear Regression and Radar.info:eu-repo/semantics/publishedVersio
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