Lista de los mamíferos terrestres del estado de Campeche, México

We present the updated taxonomic list of land mammals of the State of Campeche, which is composed of 111 species, equivalent to 22% representation at the national level; the bats, carnivores and rodents make up 80% of the records. According to the distribution of land mammals, Campeche only has a representative endemic, the subspecies Reithrodontomys gracilis insularis. Regarding the protection status of the species recorded in the state, 29% are within some category of protection in the NOM-059, while IUCN notes to all species, although 90% in minor category (LC) and, finally, 21 records are included in the CITES Appendices. In this way, this study establishes the level of knowledge of this fauna to state and national level, which is useful in the decision making process to promote the conservation and management planning for each of the species.Presentamos la lista taxonómica actualizada de los mamíferos terrestres del estado de Campeche, que se compone por 111 especies, lo que equivale al 22% de representatividad a nivel nacional; los quirópteros, carnívoros y roedores constituyen el 80% del total de los registros. De acuerdo a la distribución que siguen los mamíferos terrestres, en Campeche sólo se cuenta con un representante endémico, la subespecie Reithrodontomys gracilis insularis. En cuanto al estado de protección de las especies registradas en el Estado, se tiene que el 29% se encuentra dentro de alguna categoría de protección en la NOM-059, en tanto que la UICN anota a todas las especies, aunque el 90% en la categoría de menor importancia (LC), y por último, 21 de los  registros se incluyen en los apéndices del CITES. De este modo, el presente estudio establece el estado de conocimiento de este grupo faunístico a nivel estatal y nacional, el cual es de gran utilidad en el proceso de toma decisiones para favorecer la conservación y la planificación del manejo de cada una de las especies

Long-term effects of chronic light pollution on seasonal functions of European blackbirds (turdus merula)

Light pollution is known to affect important biological functions of wild animals, including daily and annual cycles. However, knowledge about long-term effects of chronic exposure to artificial light at night is still very limited. Here we present data on reproductive physiology, molt and locomotor activity during two-year cycles of European blackbirds (Turdus merula) exposed to either dark nights or 0.3 lux at night. As expected, control birds kept under dark nights exhibited two regular testicular and testosterone cycles during the two-year experiment. Control urban birds developed testes faster than their control rural conspecifics. Conversely, while in the first year blackbirds exposed to light at night showed a normal but earlier gonadal cycle compared to control birds, during the second year the reproductive system did not develop at all: both testicular size and testosterone concentration were at baseline levels in all birds. In addition, molt sequence in light-treated birds was more irregular than in control birds in both years. Analysis of locomotor activity showed that birds were still synchronized to the underlying light-dark cycle. We suggest that the lack of reproductive activity and irregular molt progression were possibly the results of i) birds being stuck in a photorefractory state and/or ii) chronic stress. Our data show that chronic low intensities of light at night can dramatically affect the reproductive system. Future studies are needed in order to investigate if and how urban animals avoid such negative impact and to elucidate the physiological mechanisms behind these profound long-term effects of artificial light at night. Finally we call for collaboration between scientists and policy makers to limit the impact of light pollution on animals and ecosystems

Extremely deep 150 MHz source counts from the LoTSS Deep Fields

International audienceWith the advent of new generation low-frequency telescopes, such as the LOw Frequency ARray (LOFAR), and improved calibration techniques, we have now started to unveil the subgigahertz radio sky with unprecedented depth and sensitivity. The LOFAR Two Meter Sky Survey (LoTSS) is an ongoing project in which the whole northern radio sky will be observed at 150 MHz with a sensitivity better than 100 μJy beam−1 at a resolution of 6′′. Additionally, deeper observations are planned to cover smaller areas with higher sensitivity. The Lockman Hole, the Boötes, and the Elais-N1 regions are among the most well known northern extra-galactic fields and the deepest of the LoTSS Deep Fields so far. We exploited these deep observations to derive the deepest radio source counts at 150 MHz to date. Our counts are in broad agreement with those from the literature and show the well known upturn at ≤1 mJy, mainly associated with the emergence of the star-forming galaxy population. More interestingly, our counts show, for the first time a very pronounced drop around S ~ 2 mJy, which results in a prominent “bump” at sub-mJy flux densities. Such a feature was not observed in previous counts’ determinations (neither at 150 MHz nor at a higher frequency). While sample variance can play a role in explaining the observed discrepancies, we believe this is mostly the result of a careful analysis aimed at deblending confused sources and removing spurious sources and artifacts from the radio catalogs. This “drop and bump” feature cannot be reproduced by any of the existing state-of-the-art evolutionary models, and it appears to be associated with a deficiency of active galactic nuclei (AGN) at an intermediate redshift (1 < z < 2) and an excess of low-redshift (z < 1) galaxies and/or AGN.Key words: galaxies: evolution / surveys / radio continuum: genera

Dynamics, Patterns and Causes of Fires in Northwestern Amazonia

According to recent studies, two widespread droughts occurred in the Amazon basin, one during 2005 and one during 2010. The drought increased the prevalence of climate-driven fires over most of the basin. Given the importance of human-atmosphere-vegetation interactions in tropical rainforests, these events have generated concerns over the vulnerability of this area to climate change. This paper focuses on one of the wettest areas of the basin, Northwestern Amazonia, where the interactions between the climate and fires are much weaker and where little is known about the anthropogenic drivers of fires. We have assessed the response of fires to climate over a ten-year period, and analysed the socio-economic and demographic determinants of fire occurrence. The patterns of fires and climate and their linkages in Northwestern Amazonia differ from the enhanced fire response to climate variation observed in the rest of Amazonia. The highest number of recorded fires in Northwestern Amazonia occurred in 2004 and 2007, and this did not coincide with the periods of extreme drought experienced in Amazonia in 2005 and 2010. Rather, during those years, Northwestern Amazonia experienced a relatively small numbers of fire hotspots. We have shown that fire occurrence correlated well with deforestation and was determined by anthropogenic drivers, mainly small-scale agriculture, cattle ranching (i.e., pastures) and active agricultural frontiers (including illegal crops). Thus, the particular climatic conditions for air convergence and rainfall created by proximity to the Andes, coupled with the presence of one of the most active colonisation fronts in the region, make this region differently affected by the general drought-induced fire patterns experienced by the rest of the Amazon. Moreover, the results suggest that, even in this wet region, humans are able to modify the frequency of fires and impact these historically well preserved forests

The LOFAR Two-metre Sky Survey: I. Survey description and preliminary data release⋆

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Characterization of the second- and third-harmonic optical susceptibilities of atomically thin tungsten diselenide

Supplementary information accompanies this paper at https://doi.org/10.1038/s41598-018-28374-1We report the first detailed characterization of the sheet third-harmonic optical susceptibility, χ(3)s, of tungsten diselenide (WSe2). With a home-built multiphoton microscope setup developed to study harmonics generation, we map the second and third-harmonic intensities as a function of position in the sample, pump power and polarization angle, for single- and few-layers flakes of WSe2. We register a value of |χ(3)s| ≈ 0.9 × 10-28 m3 V-2 at a fundamental excitation frequency of ℏω = 0.8 eV, which is comparable in magnitude to the third-harmonic susceptibility of other group-VI transition metal dichalcogenides. The simultaneously recorded sheet second-harmonic susceptibility is found to be |χ(2)s| ≈ 0.7 × 10-19 m2 V-1 in very good agreement on the order of magnitude with recent reports for WSe2, which asserts the robustness of our values for |χ(3)s|.Y.W.H. acknowledges scholarship support from NGS. G.E. acknowledges financial support from National Research Foundation of Singapore (NRF Research Fellowship NRF-NRFF2011-02 and medium-sized centre programme) and Ministry of Education of Singapore (AcRF Tier 2 MOE2015-T2-2-123). V. M. P. acknowledges fnancial support from Ministry of Education of Singapore (FRC AcRF Tier 1 R-144-000-386-114). J.C.V.G. acknowledges fnancial support from CA2DM through National Research Foundation of Singapore (NRF-CRP Grant No. R-144-000-295-281)