Direct and sequential radiative three-body reaction rates at low temperatures

We investigate the low-temperature reaction rates for radiative capture processes of three particles. We compare direct and sequential capture mechanisms and rates using realistic phenomenological parametrizations of the corresponding photodissociation cross sections.Energy conservation prohibits sequential capture for energies smaller than that of the intermediate two-body structure. A finite width or a finite temperature allows this capture mechanism. We study generic effects of positions and widths of two- and three-body resonances for very low temperatures. We focus on nuclear reactions relevant for astrophysics, and we illustrate with realistic estimates for the $\alpha$-$\alpha$-$\alpha$ and $\alpha$-$\alpha$-$n$ radiative capture processes. The direct capture mechanism leads to reaction rates which for temperatures smaller than 0.1 GK can be several orders of magnitude larger than those of the NACRE compilation.Comment: To be published in European Physical Journal

Recopilación de métodos analíticos para la caracterización y determinación del quitosano y las principales aplicaciones del polímero en los envases activos alimentarios

Antimicrobial films for food packaging applications have received increasing attention from the industry in recent years. Due to their exceptional properties, such as non-toxicity, biodegradability, antimicrobial characteristics, and biocompatibility, chitosan has proven useful for the development of active materials. This review aims to provide anoverview of the main techniques used for the characterization of chitin and chitosan, including Fourier transforminfrared spectroscopy (FTIR), 1H and 13C nuclear magnetic resonance (NMR) spectroscopy, UV spectrophotometry, viscosimetry, elemental analysis, X-ray diffraction (XRD), thermogravimetric analysis (TGA), titrations, scanning electron microscopy (SEM) and size exclusion chromatography (SEC) among others. In addition, the main applications of the polymer in food packaging are also reportedEn los últimos años los films antimicrobianos han recibido una gran atención por parte de la industria para su aplicación en el envasado alimentario. Debido a sus excepcionales propiedades, no-tóxico, biodegradable, características antimicrobianas y biocompatible, el quitosano ha demostrado ser útil para el desarrollo de materiales activos. Este artículo de revisión tiene por objeto proporcionar una visión general de las principales técnicas usadas para la caracterización de quitina y quitosano incluidas la espectroscopia infrarroja (FTIR), la espectroscopia RMN de 1H y 13C, la espectrofotometría UV, viscosimetría, análisis elemental, difracción de rayos-X (XRD), análisis termogravimétrico (TGA), titulaciones, microscopía electrónica de barrido (SEM) y cromatografía de exclusión por tamaños (SEC)entre otras. Además, se describen las principales aplicaciones del polímero en el envasado de los alimentosThis work was funded under the Project no. 95935 from FONCICYT C002-2008-1/ALA 127 249S

The role of nitric oxide in pulmonary arteriolar and left heart ventricle hypertrophy in chickens at sea level and exposed to high altitude hypoxia.

El objetivo del presente estudio fue determinar los valores de nitritos y nitratos, metabolitos estables del óxido nítrico (ON), y su correlación con el grado de hipertrofia arteriolar pulmonar en aves sometidas a hipoxia ambiental. Se emplearon 135 aves machos de la línea Cobb-Vantres, nacidos a nivel del mar. De estas, 120 fueron divididos en dos grupos: 60 aves criadas a nivel del mar (NM) y 60 aves criadas en altura a 3320 msnm (A), en tanto que las 15 aves restantes fueron sacrificadas al primer día de edad. Quince aves seleccionadas al azar de cada grupo fueron sacrificadas a los 10, 20, 30 y 40 días de edad. Se determinó el peso corporal (PC), hematocrito (Ht), nitritos y nitratos, relación capa muscular/diámetro arteriolar pulmonar (CM/DA), relación peso del ventrículo derecho/ peso total del ventrículo (VD/VT), y relación peso ventrículo derecho/peso corporal (VD/PC). El PC fue mayor a NM que en A (p<0.05), mientras que el Ht fue mayor en A que a NM (p<0.05). Los niveles de nitritos y nitratos a NM fueron similares en todas las edades, mientras que en A se observó una disminución a los 20 días y un aumento a los 30 días (p<0.05). En ambos grupos se observó un proceso de muscularización de las arteriolas pulmonares con la edad. Las relaciones VD/VT y VD/PC mostraron una hipertrofia ventricular derecha en las aves sometidas a hipoxia. Se encontró una correlación significativa entre los niveles de nitritos y nitratos en los diferentes tiempos de exposición a la hipoxia con las relaciones CM/DA, VD/VT y VD/PC. Se concluye que las variaciones en la producción del ON afecta el desarrollo de la musculatura lisa de las arteriolas pulmonares, produciendo una hipertrofia cardiaca derecha como mecanismo compensatorio.The aim of this study was to determine the nitrites and nitrates concentration, stable metabolites of NO, and its correlation with the degree of pulmonary arteriole hypertrophy in chickens raised at environmental hypoxia. A total of 135 Cobb-Vantres male chickens, born at sea level were used. Of this, 60 chicks raised at sea level (SL), and 60 at high altitude (A), 3230 m above sea level; while the remaining 15 birds were slaughtered at 1 day of age. Fifteen 15 chicks per group were randomly selected and slaughtered at 10, 20, 30 and 40 days of age. It was determined body weight (BW), hematocrite (Ht), nitrites and nitrates, muscular wall/arteriolar diameter (CM/DA) ratio, right ventricle weight/total ventricle weight ratio (RV/TV), and right ventricle weight/body weight ratio (RV/BW) ratio. BW was greater at SL than at A (p< 0.05), whereas Ht was greater in A than at SL (p< 0.05). The nitrites and nitrates levels at SL were similar at all ages, whereas at A decreased at 20 days and increased at 30 days (p< 0.05). A process of muscularization in the pulmonary arterioles was observed in relation to age in both groups. The RV/TV and RV/BW ratios showed a right cardiac hypertrophy in chickens raised under hypoxia. There was a significant correlation between levels of nitrites and nitrates at different times of exposition to hypoxia with MW/AD, RV/TV and RV/BW ratios. It is concluded that variations in the production of NO directly affect the proliferation of smooth muscle of pulmonary arterioles conducing to a compensatory right cardiac hypertrophy

EVALUACIÓN POSNATAL DE LAS ARTERIOLAS PULMONARES EN CRÍAS DE ALPACA

In the postnatal phase in mammalians, the vasodilatation of the pulmonary arterioles is critical, since this will affect the amount of blood passing through the alveoli for oxygenation. The aim of the study was to evaluate the diameter, the thickness of the muscle layer and the relationship muscle layer/arteriolar diameter (CM/DA) as indication of changes in the vascular lumen in the postnatal period of baby alpacas. Lungs of 36 alpacas between 1 to 45 days of age were obtained according to nine age groups (one group each 5 days of age). The lung histological sections were stained with Mallory’s phosphotungstic acid hematoxylin. The arteriolar diameter showed a significant increase (p<0.05) between age groups 1 and 2 versus 7, 8 and 9. The thickness of the muscle layer showed no significant changes between groups, while the CM/DA relationship values decreased with age (groups 1 and 2 were statistical different of groups 6, 7, 8 and 9; p<0.05). It is concluded that the CM/DA relationship decreases and the lumen of pulmonary arterioles increases according to age, and this is due to increased arteriolar diameter (p<0.05) but not to thickness of smooth muscles.En la etapa posnatal de mamíferos es de vital importancia la vasodilatación de las arteriolas pulmonares, pues de estas dependerá la cantidad de sangre que pase por los alveolos para ser oxigenada. El presente estudio tuvo por objetivo evaluar el diámetro, el grosor de la capa muscular y la relación capa muscular/diámetro arteriolar (CM/DA) para evaluar los cambios de la luz vascular en la etapa posnatal de crías de alpaca. Se utilizaron pulmones de 36 alpacas de 1 a 45 días de edad, distribuidos en nueve grupos etarios (un grupo por cada cinco días de edad). Los cortes histológicos de pulmón fueron coloreados con hematoxilina fosfotúngstica de Mallory. El diámetro arteriolar pulmonar mostró un incremento significativo (p<0.05) entre los grupos etarios 1 y 2 versus 7, 8 y 9. El grosor de la capa muscular no evidenció cambios significativos entre grupos, mientras que los valores de la relación CM/DA se incrementaron con la edad, habiendo diferencias estadísticas entre grupos etarios 1 y 2 versus 6, 7, 8 y 9 (p<0.05). Se concluye que la relación CM/DA disminuye y el lumen de las arteriolas pulmonares aumenta a medida que la edad de los animales se incrementa, debido al aumento del diámetro arteriolar pulmonar (p<0.05), mas no del grosor del músculo liso

Resistência antimicrobiana nos principais recursos aquícolas dos departamentos de Tumbes, Piura, San Martin e Puno

[Objective] The objective of this study was to analyze antimicrobial resistance in Peruvian aquaculture. [Methodology] An observational, descriptive study was carried out. Samples of Argopecten purpuratus, Oncorhynchus mykiss, Oreochromis niloticus and Litopenaeus vannamei were included. The bacteria Enterococcus spp., Salmonella spp., Escherichia coli, Vibrio parahaemolyticus, Aeromonas spp., and Flavobacterium psychrophilum were isolated. Antibiotic resistance was evaluated using antibiograms, and resistant samples were sequenced to identify antimicrobial resistance genes. Absolute and percentage frequencies were calculated. In addition, Wald, Clopper-Pearson, and pooled prevalence confidence intervals were estimated. [Results] In the case of A. purpuratus, 22.2% (95% CI:2.81-60.00) of the E. coli samples were resistant to oxytetracycline. Resistant samples were found in 4.44% (n=2) of the aquaculture production centers (APCs). In O. mykiss, 88.89% (95% CI:51.16-99.72) of the Enterococcus spp. were resistant to fosfomycin and oxytetracycline. Resistant samples were found in12.96% of the APCs (n=7). Regarding O. niloticus, 47.31% (95% CI: 37.16-57.46) of the E. coli samples were resistant to oxytetracycline>ampicilline>chloramphenicol>fosfomycin and azithromycin. Resistant samples were encountered in 50% of the APCs (n=19). In addition, 89.36% (95% CI:80.55-98.18) of the Enterococcus spp. were resistant to Fosfomycin> chloranphenicol and colistin> oxytetracycline>azithromycin>ampicilline; resistant samples were found in 36.84% of the APCs (n=14). In L. vannamei, 87.11% (95% CI:83.00-91.21) of the Enterococcus spp. samples were resistant to Fosfomycin> colistin> oxytetracycline> azithromycin>ampicilline and resistant samples were found in 100% of the APCs (n=33). Likewise, 35.05% (95% CI:29.74-40.23) of the V. parahaemolyticus samples were resistant to ampicilline>fosfomycin>oxytetracycline>azithromycin>eritromicine>enrofloxacin> ampicilline> chloranfhenicol. Resistant samples were found in 78.79% (n=26) of the APCs. [Conclusions] The percentage of APCs with O. niloticus and L. vannamei showed that antimicrobial resistance was high.[Objetivo] El objetivo fue analizar la resistencia antimicrobiana en la acuicultura peruana. [Metodología] Se realizó un estudio observacional, descriptivo. Se incluyeron muestras de las especies Argopecten purpuratus, Oncorhynchus mykiss, Oreochromis niloticus y Litopenaeus vannamei. Se aislaron bacterias del género Enterococcus spp., Salmonella spp. y Aeromonas spp., y especies de Escherichia coli, Vibrio parahaemolyticus, y Flavobacterium psychrophilum. La resistencia antimicrobiana fue evaluada mediante antibiograma y las muestras resistentes fueron secuenciadas para identificar genes de resistencia antimicrobiana. Se calculó la frecuencia absoluta y porcentual, además, se estimaron los intervalos de confianza de Wald, de Clopper-Pearson, y prevalencia agrupada. [Resultados] Respecto a A. purpuratus, el 22,2 % (IC95%:2,81-60,00) de las muestras de E. coli fueron resistentes a oxitetraciclina. Estas pertenecían al 4,44 % (n=2) de los centros de producción acuícola (CPA). En O. mykiss, el 88,89% (IC95%:51,16-99,72) de las muestras de Enterococcus spp. fueron resistentes a fosfomicina y oxitetraciclina. Estas pertenecían al 12,96 % de los CPA (n=7). En referencia a O. niloticus, el 47,31 % (IC95%: 37,16-57,46) de las muestras de E. coli fueron resistentes oxitetraciclina>ampicilina>cloranfenicol>fosfomicina y azitromicina. Estas pertenecían al 50 % de los CPA (n=19). Además, 89, 36% (IC95 %:80,55-98,18) de las muestras de Enterococcus spp. fueron resistentes a fosfomicina>cloranfenicol y colistina>oxitetraciclina>azitromicina>ampicilina; estas pertenecían al 36,84 % de los CPA (n=14). En L. vannamei, el 87,11 % (IC95%:83,00-91,21) de las muestras de Enterococcus spp. fueron resistentes a fosfomicina>colistina>oxitetraciclina>azitromicina>eritromicina>enrofloxacino> ampicilina>cloranfenicol y estas pertenecían al 100 % de los CPA (n=33). Asimismo, 35,05 % (IC95%: 29,74-40,23) de las muestras de V. parahaemolyticus fueron resistentes a ampicilina>fosfomicina>colistina>oxitetraciclina>azitromicina. Estas pertenecían al 78,79 % (n=26) de los CPA. [Conclusiones] El porcentaje de CPA de O. niloticus y L. vannamei, mostraron mayor resistencia antimicrobiana del estudio.[Objetivo] O objetivo foi analisar a resistência antimicrobiana na aquicultura peruana. [Metodologia] Foi realizado um estudo observacional, descritivo. Foram incluídas amostras das espécies Argopecten purpuratus, Oncorhynchus mykiss, Oreochromis niloticus e Litopenaeus vannamei.   Foram isoladas bactérias dos gêneros Enterococcus spp., Salmonella spp., Aeromonas spp., e espécies de Escherichia coli, Vibrio parahaemolyticus e Flavobacterium psychrophilum. A resistência antimicrobiana foi avaliada por meio de antibiograma, e amostras resistentes foram sequenciadas para identificar genes de resistência antimicrobiana. Foram calculadas as frequências absoluta e percentual, além dos intervalos de confiança de Wald, Clopper-Pearson e as prevalências agrupadas. [Resultados] Em relação a A. purpuratus, 22,2% (IC 95%: 2,81-60,00) das amostras de E. coli foram resistentes à oxitetraciclina. Estes pertenciam a 4,44 % (n=2) dos centros de produção aquícola (CPA). Em O. mykiss, 88,89% (IC 95%: 51,16-99,72) das amostras de Enterococcus spp. foram resistentes à fosfomicina e oxitetraciclina.  Estas pertenciam a 12,96% das CPAs (n=7). Em relação a O. niloticus, 47,31 % (IC 95%: 37,16-57,46) das amostras de E. coli foram resistentes à oxitetraciclina>ampicilina>cloranfenicol>fosfomicina e azitromicina. Estas pertenciam a 50% das CPAs (n=19). Além disso, 89,36% (IC95%: 80,55-98,18) das amostras de Enterococcus spp. foram resistentes a fosfomicina>cloranfenicol e colistina>oxitetraciclina>azitromicina>ampicilina; estas pertenciam a 36,84% das CPAs (n=14). Em L. vannamei, 87,11% (IC 95%: 83,00-91,21) das amostras de Enterococcus spp foram resistentes à fosfomicina>colistina>oxitetraciclina>azitromicina>eritromicina>enrofloxacina> ampicilina>cloranfenicol e pertenciam a 100% das CPAs (n=33). Além disso, 35,05% (IC 95%: 29,74-40,23) das amostras de V. parahaemolyticus foram resistentes à ampicilina>fosfomicina>colistina>oxitetraciclina>azitromicina. Estas pertenciam a 78,79% (n=26) das CPAs. [Conclusões] A porcentagem de CPA de O. niloticus e L. vannamei, mostrou maior resistência antimicrobiana do estudo

OSIRIS – The scientific camera system onboard Rosetta

The Optical, Spectroscopic, and Infrared Remote Imaging System OSIRIS is the scientific camera system onboard the Rosetta spacecraft (Figure 1). The advanced high performance imaging system will be pivotal for the success of the Rosetta mission. OSIRIS will detect 67P/Churyumov-Gerasimenko from a distance of more than 106 km, characterise the comet shape and volume, its rotational state and find a suitable landing spot for Philae, the Rosetta lander. OSIRIS will observe the nucleus, its activity and surroundings down to a scale of ~2 cm px−1. The observations will begin well before the onset of cometary activity and will extend over months until the comet reaches perihelion. During the rendezvous episode of the Rosetta mission, OSIRIS will provide key information about the nature of cometary nuclei and reveal the physics of cometary activity that leads to the gas and dust coma. OSIRIS comprises a high resolution Narrow Angle Camera (NAC) unit and a Wide Angle Camera (WAC) unit accompanied by three electronics boxes. The NAC is designed to obtain high resolution images of the surface of comet 7P/Churyumov-Gerasimenko through 12 discrete filters over the wavelength range 250–1000 nm at an angular resolution of 18.6 μrad px−1. The WAC is optimised to provide images of the near-nucleus environment in 14 discrete filters at an angular resolution of 101 μrad px−1. The two units use identical shutter, filter wheel, front door, and detector systems. They are operated by a common Data Processing Unit. The OSIRIS instrument has a total mass of 35 kg and is provided by institutes from six European countrie

Relationship of Weather Types on the Seasonal and Spatial Variability of Rainfall, Runoff, and Sediment Yield in the Western Mediterranean Basin

Rainfall is the key factor to understand soil erosion processes, mechanisms, and rates. Most research was conducted to determine rainfall characteristics and their relationship with soil erosion (erosivity) but there is little information about how atmospheric patterns control soil losses, and this is important to enable sustainable environmental planning and risk prevention. We investigated the temporal and spatial variability of the relationships of rainfall, runoff, and sediment yield with atmospheric patterns (weather types, WTs) in the western Mediterranean basin. For this purpose, we analyzed a large database of rainfall events collected between 1985 and 2015 in 46 experimental plots and catchments with the aim to: (i) evaluate seasonal differences in the contribution of rainfall, runoff, and sediment yield produced by the WTs; and (ii) to analyze the seasonal efficiency of the different WTs (relation frequency and magnitude) related to rainfall, runoff, and sediment yield. The results indicate two different temporal patterns: the first weather type exhibits (during the cold period: autumn and winter) westerly flows that produce the highest rainfall, runoff, and sediment yield values throughout the territory; the second weather type exhibits easterly flows that predominate during the warm period (spring and summer) and it is located on the Mediterranean coast of the Iberian Peninsula. However, the cyclonic situations present high frequency throughout the whole year with a large influence extended around the western Mediterranean basin. Contrary, the anticyclonic situations, despite of its high frequency, do not contribute significantly to the total rainfall, runoff, and sediment (showing the lowest efficiency) because of atmospheric stability that currently characterize this atmospheric pattern. Our approach helps to better understand the relationship of WTs on the seasonal and spatial variability of rainfall, runoff and sediment yield with a regional scale based on the large dataset and number of soil erosion experimental stations.Spanish Government (Ministry of Economy and Competitiveness, MINECO) and FEDER Projects: CGL2014 52135-C3-3-R, ESP2017-89463-C3-3-R, CGL2014-59946-R, CGL2015-65569-R, CGL2015-64284-C2-2-R, CGL2015-64284-C2-1-R, CGL2016-78075-P, GL2008-02879/BTE, LEDDRA 243857, RECARE-FP7, CGL2017-83866-C3-1-R, and PCIN-2017-061/AEI. Dhais Peña-Angulo received a “Juan de la Cierva” postdoctoral contract (FJCI-2017-33652 Spanish Ministry of Economy and Competitiveness, MEC). Ana Lucia acknowledge the "Brigitte-Schlieben-Lange-Programm". The “Geoenvironmental Processes and Global Change” (E02_17R) was financed by the Aragón Government and the European Social Fund. José Andrés López-Tarazón acknowledges the Secretariat for Universities and Research of the Department of the Economy and Knowledge of the Autonomous Government of Catalonia for supporting the Consolidated Research Group 2014 SGR 645 (RIUS- Fluvial Dynamics Research Group). Artemi Cerdà thank the funding of the OCDE TAD/CRP JA00088807. José Martínez-Fernandez acknowledges the project Unidad de Excelencia CLU-2018-04 co-funded by FEDER and Castilla y León Government. Ane Zabaleta is supported by the Hydro-Environmental Processes consolidated research group (IT1029-16, Basque Government). This paper has the benefit of the Lab and Field Data Pool created within the framework of the COST action CONNECTEUR (ES1306)

SDSS-IV eBOSS emission-line galaxy pilot survey

The Sloan Digital Sky Survey IV extended Baryonic Oscillation Spectroscopic Survey (SDSS-IV/eBOSS) will observe 195 000 emission-line galaxies (ELGs) to measure the baryonic acoustic oscillation (BAO) standard ruler at redshift 0.9. To test different ELG selection algorithms, 9000 spectra were observed with the SDSS spectrograph as a pilot survey based on data from several imaging surveys. First, using visual inspection and redshift quality flags, we show that the automated spectroscopic redshifts assigned by the pipeline meet the quality requirements for a reliable BAO measurement. We also show the correlations between sky emission, signal-to-noise ratio in the emission lines, and redshift error. Then we provide a detailed description of each target selection algorithm we tested and compare them with the requirements of the eBOSS experiment. As a result, we provide reliable redshift distributions for the different target selection schemes we tested. Finally, we determine an target selection algorithms that is best suited to be applied on DECam photometry because they fulfill the eBOSS survey efficiency requirements

High Levels of Diversity Uncovered in a Widespread Nominal Taxon: Continental Phylogeography of the Neotropical Tree Frog

Species distributed across vast continental areas and across major biomes provide unique model systems for studies of biotic diversification, yet also constitute daunting financial, logistic and political challenges for data collection across such regions. The tree frog Dendropsophus minutus (Anura: Hylidae) is a nominal species, continentally distributed in South America, that may represent a complex of multiple species, each with a more limited distribution. To understand the spatial pattern of molecular diversity throughout the range of this species complex, we obtained DNA sequence data from two mitochondrial genes, cytochrome oxidase I (COI) and the 16S rhibosomal gene (16S) for 407 samples of D. minutus and closely related species distributed across eleven countries, effectively comprising the entire range of the group. We performed phylogenetic and spatially explicit phylogeographic analyses to assess the genetic structure of lineages and infer ancestral areas. We found 43 statistically supported, deep mitochondrial lineages, several of which may represent currently unrecognized distinct species. One major clade, containing 25 divergent lineages, includes samples from the type locality of D. minutus. We defined that clade as the D. minutus complex. The remaining lineages together with the D. minutus complex constitute the D. minutus species group. Historical analyses support an Amazonian origin for the D. minutus species group with a subsequent dispersal to eastern Brazil where the D. minutus complex originated. According to our dataset, a total of eight mtDNA lineages have ranges >100,000 km2. One of them occupies an area of almost one million km2 encompassing multiple biomes. Our results, at a spatial scale and resolution unprecedented for a Neotropical vertebrate, confirm that widespread amphibian species occur in lowland South America, yet at the same time a large proportion of cryptic diversity still remains to be discovered