Linear chemically sensitive electron tomography using DualEELS and compressed sensing

No abstract available

Linear chemically sensitive electron tomography using DualEELS and dictionary-based compressed sensing

We have investigated the use of DualEELS in elementally sensitive tilt series tomography in the scanning transmission electron microscope. A procedure is implemented using deconvolution to remove the effects of multiple scattering, followed by normalisation by the zero loss peak intensity. This is performed to produce a signal that is linearly dependent on the projected density of the element in each pixel. This method is compared with one that does not include deconvolution (although normalisation by the zero loss peak intensity is still performed). Additionaly, we compare the 3D reconstruction using a new compressed sensing algorithm, DLET, with the well-established SIRT algorithm. VC precipitates, which are extracted from a steel on a carbon replica, are used in this study. It is found that the use of this linear signal results in a very even density throughout the precipitates. However, when deconvolution is omitted, a slight density reduction is observed in the cores of the precipitates (a so-called cupping artefact). Additionally, it is clearly demonstrated that the 3D morphology is much better reproduced using the DLET algorithm, with very little elongation in the missing wedge direction. It is therefore concluded that reliable elementally sensitive tilt tomography using EELS requires the appropriate use of DualEELS together with a suitable reconstruction algorithm, such as the compressed sensing based reconstruction algorithm used here, to make the best use of the limited data volume and signal to noise inherent in core-loss EELS

ESTIMACIÓN DE LA POBLACIÓN DE PERROS CALLEJEROS EN EL DISTRITO DE LOS OLIVOS, LIMA, PERÚ

The aim of this study was to estimate and characterize the stray dog population in Los Olivos district, Lima, during the period November - December 2012. Eight of the 34 areas that comprise the district according the map of Los Olivos Municipality were selected. The selection of the areas was at random; dog population counting and calculations were based on the criteria outlined in the guide of the World Society for the Protection of Animals entitled «Recensusing roaming dog populations: guidelines on methodology». Three consecutive sampling were performed at daytime and evening hours in each area. The average of the three measurements was used for statistical calculations. There was an average of 332 stray dogs at daytime and 217 stray dogs at evening; males and bigger dogs were observed in higher number. Most of the dogs showed low body condition score. The estimated number of stray dogs in the district was 1411 ± 643 at daytime and 922 ± 497 at night. Results are expected to contribute with the dog control population programme that is being implemented by the Municipality of Los Olivos.El objetivo del estudio fue estimar y caracterizar la población de perros callejeros en el distrito de Los Olivos durante el periodo noviembre y diciembre 2012. Para ello se seleccionaron 8 de las 34 zonas que divide al distrito en el plano municipal. La selección de las zonas fue de forma aleatoria y para el conteo y cálculos de la población de perros se utilizaron los criterios expuestos en la guía «Censando poblaciones de perros calleje- ros: guía metodológica» de la World Society for the Protection of Animals. Se realizaron tres muestreos consecutivos en horarios diurno y nocturno en cada zona. Se utilizó la media de las tres mediciones para realizar los cálculos estadísticos. El estudio reportó un promedio de 332 perros callejeros en horario diurno y de 217 en horario nocturno. Los animales machos y los de tamaño grande se observaron en mayor número. La mayoría de perros poseía un índice de condición corporal bajo. La estimación del número de perros callejeros en el distrito fue de 1 411 ± 643 en horario diurno y de 922 ± 497 en horario nocturno. Se espera que los resultados aporten información de línea base al programa de control poblacional canino que viene trabajando la Municipalidad Distrital de Los Olivos

Dinitrogen emissions: an overlooked key component of the N balance of montane grasslands

While emissions of nitric oxide (NO), ammonia (NH₃) and nitrous oxide (N₂O) from grassland soils have been increasingly well constrained, soil dinitrogen (N₂) emissions are poorly understood. However, N₂ losses might dominate total gaseous nitrogen (N) losses. Knowledge on N losses is key for the development of climate-adapted management that balances agronomic and environmental needs. Hence, we quantified all gaseous N losses from a montane grassland in Southern Germany both for ambient climatic conditions and for a climate change treatment (+ 2°C MAT, - 300 mm MAP). Monthly measurements of soil N₂ emissions of intact soil cores revealed that those exceeded by far soil N₂O emissions and averaged at 350 ± 101 (ambient climate) and 738 ± 197 lg N m¯²h¯¹ (climate change). Because these measurements did not allow to quantify emission peaks after fertilization, an additional laboratory experiment was deployed to quantify the response of NH₃, NO, N₂O, and N₂ emissions in sub daily temporal resolution to a typical slurry fertilization event (51 kg N ha¯¹). Our results revealed that total N gas losses amounted to roughly half of applied slurry-N. Surprisingly, N₂ but not NH₃ dominated fertilizer N losses, with N₂ emissions accounting for 16–21 kg or 31–42% of the applied slurry-N, while NH₃ volatilization (3.5 kg), N2O (0.2–0.5 kg) and NO losses (0–0.2 kg) were of minor importance. Though constraining annual N₂ loss remained uncertain due to high spatiotemporal variability of fluxes, we show that N₂ losses are a so far overlooked key component of the N balance in montane grasslands, which needs to be considered for developing improved grassland management strategies targeted at increasing N use efficiency

Genetic composition and origin of juvenile green turtles foraging at Culebra, Puerto Rico, as revealed by mtDNA

Marine migratory species encounter a range of threats as they move through coastal and oceanic zones. Understanding the connectivity and dispersal patterns of such species is critical to their effective conservation. Here we analyzed the temporal genetic composition and the most likely origin of juvenile green turtles foraging at Puerto Manglar and Tortuga Bay, Culebra, Puerto Rico, using mitochondrial DNA control region sequences. We identified 17 haplotypes, of which CM-A3 (51.5%), CM-A5 (19.4%) and CM-A1 (13.6%) were the most common. Haplotype (h) and nucleotide (π) diversities were 0.680 and 0.008, respectively. There was no evidence of significant variation in the genetic composition of these aggregations throughout seven years (2000-2006), suggesting that relative contributions from source populations did not significantly change during this period. Mixed Stock Analysis (MSA), incorporating 14 Atlantic nesting populations as possible sources, indicated four main contributing stocks to the Culebra foraging grounds: Costa Rica (34.9%), Mexico (29.2%), East Central Florida (13.2%), and Suriname (12.0%). The regional pattern of connectivity among Wider Caribbean rookeries and Culebra was further evidenced by a second MSA using Atlantic Regional Management Units (RMUs) as sources, with 94.1% of the mixed stock attributed to this area. This study addresses the information gap on the connectivity of the green turtle in the North Atlantic, and establishes an important baseline that can be used to determine future changes in stock composition.Department of Natural and Environ-mental Resources of Puerto Rico; US National Marine Fisheries Service (NMFS-NOAA, Section 6, grant NA08NMF4720436); US Fish and Wildlife Service, Chelonia Inc, and WIDECAST. Work was conducted under permits by NMFS-NOAA (permit nos. 1253, 1518, 14949) and DNER (06-EPE-016). ARP had the support of the Portuguese Foundation for Science and Technologyinfo:eu-repo/semantics/publishedVersio

Bathyraja multispinis, Multispine Skate

The Multispine Skate (Bathyraja multispinis) is a medium-sized (to 126 cm total length) skate that occurs in the Southeast Pacific Ocean from Coquimbo, Chile to Cape Horn and in the Southwest Atlantic Ocean from Santa Catarina, Brazil to Tierra del Fuego and the Falkland Islands (Malvinas) and is demersal on the continental and insular shelves and slopes at depths of 70-740 m. It is captured in demersal trawl and longline fisheries that operate throughout its range and there is little refuge at depth; it is likely to be retained for sale for human consumption in the Southwest Atlantic, but is discarded dead in the Southeast Pacific. Across its range, skates are typically not recorded or managed at the species level, and there are no estimates of population size. In Argentina, there are no species-specific data, but rays in general declined in catch-per-unit-effort (CPUE) in the 1990s and early 2000s. In the Falkland Islands (Malvinas) target skate fishery, this species showed an either stable or increasing trend in CPUE over the time-series from 1994 to 2013. Overall, due to the level of inadequately managed fisheries it is exposed to, general declines of skates in some parts of its range, and its lack of refuge at depth, balanced with the increase in CPUE in the Falkland Islands (Malvinas), it is suspected that this skate has undergone a population reduction of 20-29% over the past three generations (45 years). Therefore, the Multispine Skate is assessed as Near Threatened, nearly meeting the threshold for Vulnerable A2bd.Fil: Pollom, R.. University Fraser Simon; CanadáFil: Dulvy, N. K.. University Fraser Simon; CanadáFil: Acuña, E.. Universidad Católica del Norte; ChileFil: Bustamante, C.. Universidad de Antofagasta; ChileFil: Charvet, P.. Universidade Federal do Paraná; BrasilFil: Chiaramonte, Gustavo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia". Estación Hidrobiológica de Puerto Quequén (sede Quequén); ArgentinaFil: Cuevas, J. M.. Wildlife Conservation Society; Estados UnidosFil: Herman, K.. Georgia Aquarium; Estados UnidosFil: Paesch, L.. Dirección Nacional de Recursos Acuáticos; UruguayFil: Pompert, J.. No especifíca;Fil: Velez Zuazo, X.. Smithsonian Conservation Biology Institute; Estados Unido

Bathyraja brachyurops, Broadnose Skate

The Broadnose Skate (Bathyraja brachyurops) is a medium-sized (to 125 cm total length) skate that occurs in the Southeast Pacific and Southwest Atlantic Oceans from Biobío, Chile, south around Cape Horn and north to Rio Grande do Sul, Brazil, including the Falkland Islands (Malvinas). It is demersal on the inner continental shelf and upper slope at depths of 28?604 m. This skate is taken as bycatch in inadequately-managed demersal trawl and longline fisheries throughout most of its range. In the Argentina-Uruguay Common Fishing Zone, it is taken as bycatch but recorded with all other coastal skates. Species-specific catch time-series for Argentinian fisheries are unavailable, but overall skate landings were minimal prior to 1994 before rising rapidly and reaching a peak in 2007 and then dropping again until 2017. It is one of the main species captured in the Falkland Islands (Malvinas) multispecies target skate fishery, where the catch-per-unit-effort time-series suggests its relative abundance increased over the period 1994?2013. In Chile, it is a retained bycatch of the commercial longline fishery targeting Yellownose Skate, and in trawl fisheries targeting Chilean Hake and crustaceans. Overall, due to the level of fishing pressure that this skate is exposed to throughout much of its geographic range, its limited refuge at depth, its continued common presence in fisheries catches, and its moderately productive life history that allows it to withstand some fishing pressure, combined with an increasing trend in the Falkland Islands (Malvinas) and declines in skates in general elsewhere in its range, it is suspected that a population reduction of 20-29% has occurred over the past three generations (42 years). Therefore, the Broadnose Skate is assessed as Near Threatened, nearly meeting the threshold under criterion A2bd.Fil: Pollom, R.. University Fraser Simon; CanadáFil: Dulvy, N. K.. University Fraser Simon; CanadáFil: Acuña, E.. Universidad Católica del Norte; ChileFil: Bustamante, C.. Universidad de Antofagasta; ChileFil: Charvet, P.. Universidade Federal do Paraná; BrasilFil: Chiaramonte, Gustavo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia". Estación Hidrobiológica de Puerto Quequén (sede Quequén); ArgentinaFil: Cuevas, J. M.. Wildlife Conservation Society; Estados UnidosFil: Herman, K.. Georgia Aquarium; Estados UnidosFil: Paesch, L.. Dirección Nacional de Recursos Acuáticos; UruguayFil: Pompert, J.. No especifíca;Fil: Velez Zuazo, X.. No especifíca

Aprendizaje y consolidación de la asignatura de microbiología y parasitología medicas en la carrera de medicina.

Se aplicó un instrumento evaluativo de las esencialidades de la asignatura Microbiología y Parasitología Médicas (Agentes biológicos), en forma de encuesta anónima, a los estudiantes de Medicina de la Facultad "General Calixto García", quienes cursaron la asignatura en el 4to Semestre del curso 2003-2004, en varios Cortes: I antes de Propedéutica, al iniciar el 5to Semestre; II después de Medicina Interna, al finalizar el 6to Semestre; III después de Pediatría, al finalizar el 8vo Semestre y IV después de MGI II, en el Internado, para conocer si el futuro Médico General Básico (MGB), se había apropiado de esos conocimientos en la asignatura y valorar su consolidación en el Área Clínica. Los alumnos no demostraron el conocimiento esperado de los agentes causales de enfermedades infecciosas frecuentes en la población, no hubo retención de los objetivos instructivos de la asignatura y en el área clínica no se logró la consolidación de dichos objetivos.  Palabras clave: Docencia, evaluación, aprendizaje, asignatura

Quantifying the contribution of land use to N2O, NO and CO2 fluxes in a montane forest ecosystem of Kenya

Increasing demand for food and fibre by the growing human population is driving significant land use (LU) change from forest into intensively managed land systems in tropical areas. But empirical evidence on the extent to which such changes affect the soil-atmosphere exchange of trace gases is still scarce, especially in Africa. We investigated the effect of LU on soil trace gas production in the Mau Forest Complex region, Kenya. Intact soil cores were taken from natural forest, commercial and smallholder tea plantations, eucalyptus plantations and grazing lands, and were incubated in the lab under different soil moisture conditions. Soil fluxes of nitrous oxide (N2O), nitric oxide (NO) and carbon dioxide (CO2) were quantified, and we approximated annual estimates of soil N2O and NO fluxes using soil moisture values measured in situ. Forest and eucalyptus plantations yielded annual fluxes of 0.3-1.3 kg N2O-N ha(-1) a(-1) and 1.5-5.2 kg NO-N ha(-1) a(-1). Soils of commercial tea plantations, which are highly fertilized, showed higher fluxes (0.9 kg N2O-N ha(-1) a(-1) and 4.3 kg NO-N ha(-1) a(-1)) than smallholder tea plantations (0.1 kg N2O-N ha(-1) a(-1) and 2.1 kg NO-N ha(-1) a(-1)) or grazing land (0.1 kg N2O-N ha(-1) a(-1) and 1.1 kg NO-N ha(-1) a(-1)). High soil NO fluxes were probably the consequence of long-term N fertilization and associated soil acidification, likely promoting chemodenitrification. Our experimental approach can be implemented in understudied regions, with the potential to increase the amount of information on production and consumption of trace gases from soils

PDL1 Signals through Conserved Sequence Motifs to Overcome Interferon-Mediated Cytotoxicity

PDL1 blockade produces remarkable clinical responses, thought to occur by T cell reactivation through prevention of PDL1-PD1 T cell inhibitory interactions. Here, we find that PDL1 cell-intrinsic signaling protects cancer cells from interferon (IFN) cytotoxicity and accelerates tumor progression. PDL1 inhibited IFN signal transduction through a conserved class of sequence motifs that mediate crosstalk with IFN signaling. Abrogation of PDL1 expression or antibody-mediated PDL1 blockade strongly sensitized cancer cells to IFN cytotoxicity through a STAT3/caspase-7-dependent pathway. Moreover, somatic mutations found in human carcinomas within these PDL1 sequence motifs disrupted motif regulation, resulting in PDL1 molecules with enhanced protective activities from type I and type II IFN cytotoxicity. Overall, our results reveal a mode of action of PDL1 in cancer cells as a first line of defense against IFN cytotoxicity