596 research outputs found
Are white storks addicted to junk food? Impacts of landfill use on the movement and behaviour of resident white storks (Ciconia ciconia) from a partially migratory population
Background: The migratory patterns of animals are changing in response to global environmental change with many species forming resident populations in areas where they were once migratory. The white stork (Ciconia ciconia) was wholly migratory in Europe but recently guaranteed, year-round food from landfill sites has facilitated the establishment of resident populations in Iberia. In this study 17 resident white storks were fitted with GPS/GSM data loggers (including accelerometer) and tracked for 9.1 ± 3.7 months to quantify the extent and consistency of landfill attendance by individuals during the non-breeding and breeding seasons and to assess the influence of landfill use on daily distances travelled, percentage of GPS fixes spent foraging and non-landfill foraging ranges. Results: Resident white storks used landfill more during non-breeding (20.1 % ± 2.3 of foraging GPS fixes) than during breeding (14.9 % ± 2.2). Landfill attendance declined with increasing distance between nest and landfill in both seasons. During non-breeding a large percentage of GPS fixes occurred on the nest throughout the day (27 % ± 3.0 of fixes) in the majority of tagged storks. This study provides first confirmation of year-round nest use by resident white storks. The percentage of GPS fixes on the nest was not influenced by the distance between nest and the landfill site. Storks travelled up to 48.2 km to visit landfills during non-breeding and a maximum of 28.1 km during breeding, notably further than previous estimates. Storks nesting close to landfill sites used landfill more and had smaller foraging ranges in non-landfill habitat indicating higher reliance on landfill. The majority of non-landfill foraging occurred around the nest and long distance trips were made specifically to visit landfill. Conclusions: The continuous availability of food resources on landfill has facilitated year-round nest use in white storks and is influencing their home ranges and movement behaviour. White storks rely on landfill sites for foraging especially during the non-breeding season when other food resources are scarcer and this artificial food supplementation probably facilitated the establishment of resident populations. The closure of landfills, as required by EU Landfill Directives, will likely cause dramatic impacts on white stork populations
Deep Shape Matching
We cast shape matching as metric learning with convolutional networks. We
break the end-to-end process of image representation into two parts. Firstly,
well established efficient methods are chosen to turn the images into edge
maps. Secondly, the network is trained with edge maps of landmark images, which
are automatically obtained by a structure-from-motion pipeline. The learned
representation is evaluated on a range of different tasks, providing
improvements on challenging cases of domain generalization, generic
sketch-based image retrieval or its fine-grained counterpart. In contrast to
other methods that learn a different model per task, object category, or
domain, we use the same network throughout all our experiments, achieving
state-of-the-art results in multiple benchmarks.Comment: ECCV 201
Efectos del vibrado del pino piñonero (Pinus pinea L.) en el vigor de los árboles: densidad de copa, crecimiento de guías y parásitos de debilidad
In the Northwest of Spain the mechanized harvesting of pine cones is more and more frequenIn order to quantify the effects of vibration on the vigor of the trees, parcels of stone pine were planted in plateau and countryside. Both the mechanized and manual harvests were analyzed in adult and young trees. The growth of the tree shoots was measured. The presence and abundance of three insect plagues was analyzed in those same trees: Tomicus piniperda, Rhyacionia buoliana and Thaumetopoea pityocampa. The average shoot length of those trees manually harvested was superior to that of those mechanically harvested. The difference was very significant in young trees (40-50 years old) in the countryside and in adult trees (more than 80 years) on the plateau. Rhyacionia buoliana was more abundant in adult trees that young trees, but the relation of its abundance with the harvest method was not seen. The presence of Tomicus piniperda was rare and was only detected in mechanically harvested stands. Thaumetopoea pityocampa was more frequent in trees harvested by hand than those harvested mechanically and was more abundant in young stands. The percentage tree of defoliation was low in all stands independent of harvest method.En el noroeste de España es cada vez más frecuente la recolección mecanizada de piña. Para cuantificar los efectos del vibrado sobre el vigor de los árboles se instalaron en montes de páramo y de campiña parcelas donde se realizó cosecha mecanizada y manual en arbolado adulto y joven. Se midió el crecimiento de los brotes y se analizó la presencia y abundancia de tres insectos plaga sobre estos árboles, Tomicus piniperda y Rhyacionia buoliana, considerados parásitos de debilidad, así como Thaumetopoea pityocampa. La longitud media de los brotes fue superior en árboles cosechados manualmente. La diferencia es importante en árboles jóvenes (40-50 años) de campiñas y en árboles adultos (más de 80 años) de páramos. Rhyacionia buoliana fue más abundante en árboles adultos que en arbolado joven, pero no se vio relación de su abundancia con el método de cosecha. Tomicus piniperda fue escaso y sólo se detectó en rodales cosechados mecanizadamente. Thaumetopoea pityocampa es más frecuente en rodales cosechados manualmente, y en rodales jóvenes lo que indica que selecciona los árboles de crecimiento más vigoroso para alimentarse. Los porcentajes de defoliación fueron bajos en todas las parcelas
Design and evaluation of PM Ti surfaces modified by colloidal techniques and diffusion processes for biomedical applications
The aim of this work was the modification of the composition and surface microstructure of powder metallurgy titanium to improve the wear resistance and reduce the elastic modulus while maintaining the corrosion behavior, characteristics needed for biomedical applications. For this purpose, Mo and Nb coatings were produced by colloidal techniques. Stable aqueous suspensions were prepared from micro-sized powder of Mo and Nb particles, deposited onto the powder metallurgy titanium substrates (green or sintered). After a heat treatment to promote the diffusion and the consolidation of the layers, microstructural changes were obtained. In the case of green substrates, the co-sintering process provides a diffusion depth of 85-100 micron. In the as-sintered case, a uniform depth of 40-65 microns was reached. The surfaces were characterised by micro-hardness, corrosion and tribocorrosion testing, and the results showed that hardened surfaces presented lower tendency to corrosion both under static conditions and under sliding.Funds were provided by Spanish Government (programme MINECO, ref. MAT2012-38650-C02-01), Regional Government of Madrid (programme MULTIMAT-CHALLENGE, ref. S2013/MIT-2862) and Institute of Alvaro Alonso Barba (IAAB) for the research stay in CMEMS-UMINHO (University of Minho).info:eu-repo/semantics/publishedVersio
On the defect pattern evolution in sapphire irradiated by swift ions in a broad fluence range
Sapphire samples, irradiated with swift Kr (245 MeV) ions at room temperature in a broad fluence range, were investigated using a continuous and a pulsed positron beam to study the defect structure created by the passage of the ions in depths of a few micrometers. At small doses, monovacancies were identified as dominant defects and positron trapping centres. These monovacancies are assumed to be highly concentrated inside a cylindrical volume around the ion path with an estimated radius of ~1.5 nm. For higher doses a second type of trapping centre emerges. This second class of structural imperfection was associated with the overlap of the individual ion tracks leading to the formation of larger vacancy clusters or voids.http://www.sciencedirect.com/science/article/B6THY-4SHF49N-1S/1/3eb43650299e0466e76cbbbfdaca9fa
Positron annihilation and constant photocurrent method measurements on a-Si:H films: A comparative approach to defect identification
Defect structure of hydrogenated amorphous silicon thin-films was studied by positron annihilation spectroscopy (PAS), whereas the density of states below the Fermi level was measured by constant photocurrent method (CPM). Divacancies and large vacancy clusters were identified as the main defects present in these films, with relative concentrations strongly dependent on the rf-power. Correlation between PAS, CPM results and I(V) characteristics of solar cells suggests the creation of energy levels above the Fermi energy, not observable by CPM, related to large vacancy clusters.http://www.sciencedirect.com/science/article/B6TVT-4JX373P-2/1/af7c69b0fdf17cefb2432fb357d5d86
Mutation rate of SARS-CoV-2 and emergence of mutators during experimental evolution
Free PMC article: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8996265/Background and objectives: To understand how organisms evolve, it is fundamental to study how
mutations emerge and establish. Here, we estimated the rate of mutation accumulation of SARS-CoV-
2 in vitro and investigated the repeatability of its evolution when facing a new cell type but no immune
or drug pressures.
Methodology: We performed experimental evolution with two strains of SARS-CoV-2, one carrying the
originally described spike protein (CoV-2-D) and another carrying the D614G mutation that has spread
worldwide (CoV-2-G). After 15 passages in Vero cells and whole genome sequencing, we characterized
the spectrum and rate of the emerging mutations and looked for evidences of selection across the
genomes of both strains.
Results: From the frequencies of the mutations accumulated, and excluding the genes with signals of
selection, we estimate a spontaneous mutation rate of 1.3 10 6 6 0.2 10 6 per-base per-infection
cycle (mean across both lineages of SARS-CoV-262SEM). We further show that mutation accumulation
is larger in the CoV-2-D lineage and heterogeneous along the genome, consistent with the action
of positive selection on the spike protein, which accumulated five times more mutations than the corresponding genomic average. We also observe the emergence of mutators in the CoV-2-G background, likely linked to mutations in
the RNA-dependent RNA polymerase and/or in the error-correcting exonuclease protein.
Conclusions and implications: These results provide valuable information on how spontaneous mutations emerge in SARS-CoV-2 and
on how selection can shape its genome toward adaptation to new environments.
Lay Summary: Each time a virus replicates inside a cell, errors (mutations) occur. Here, via laboratory propagation in cells originally
isolated from the kidney epithelium of African green monkeys, we estimated the rate at which the SARS-CoV-2 virus mutates—an important
parameter for understanding how it can evolve within and across humans. We also confirm the potential of its Spike protein to
adapt to a new environment and report the emergence of mutators—viral populations where mutations occur at a significantly faster
rate.M.A. was supported by ‘Fundação para a Ciência e Tecnologia’ (FCT), fellowships PD/BD/138735/2018. Research was supported by FCT Project PTDC/BIA-EVL/31528/2017 to I.G. and by funds from Portuguese NIH.info:eu-repo/semantics/publishedVersio
Occurrence of bufotenin in the Osteocephalus genus (Anura: Hylidae).
Bufotenin (5-hydroxy-N,N-dimetyltryptamine) is a tryptamine alkaloid widely spread among anuran families as a component of their chemical defense system, acting as a potent hallucinogenic factor, showing similar activity to LSD upon interaction with the 5HT2 human receptor. This work demonstrates the presence of bufotenin in the skin secretion of three arboreal amphibian species of the Osteocephalus genus (Osteocephalus taurinus, Osteocephalus oophagus and Osteocephalus langsdorffii) from the Amazon and the Atlantic rain forests using RP-HPLC, ESI-MS/MS, UV, IR and multidimensional NMR techniques. To our knowledge, this is the first description of bufotenin in the Osteocephalus genus, so far
Cabergoline for suppression of puerperal lactation in a prevention of mother-to-child HIV-transmission programme in rural Malawi.
This study shows that cabergoline (single oral-dose) is an acceptable, safe and effective drug for suppressing puerperal lactation. It could be of operational benefit not only for artificial feeding, but also for weaning in those that breast-feed within preventive mother-to-child HIV transmission programmes in resource-limited settings
Positron and positronium annihilation patterns in zeolites and bulk ceramics
Positron lifetime (LT) measurements have revealed that in porous media the annihilation pattern is probably dominated by a near-saturation level trapping both for the positron and the positronium as well, which masks the contribution from the ldquofree annihilationrdquo, i.e., annihilation from delocalised positrons. In this work we compare positron lifetime spectra of crystalline zeolites with bulk ceramic materials fabricated by sintering from the same constituents as the zeolites and analyse common features and differences between them. For the dense ceramic samples the contribution from long-living components to the annihilation pattern is substantially lower than that for the zeolites. The results are analysed with the aim to extract new knowledge for the zeolites and for the sensitivity limits for free volume studies in ceramics. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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