3,977 research outputs found

    Light charged Higgs boson production at the Large Hadron electron Collider

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    We study the production of a light charged Higgs boson at the future Large Hadron electron Collider (LHeC), through the process e−p→νeH−qe^- p \to \nu_e H^- q considering both decay channels H−→bcˉH^- \to b \bar c and H−→τνˉτH^- \to \tau \bar \nu_\tau in the final state. We analyse these processes in the context of the 2-Higgs Doublet Model Type III (2HDM-III) and assess the LHeC sensitivity to such H−H^- signals against a variety of both reducible and irreducible backgrounds. We confirm that prospects for H−H^- detection in the 2HDM-III are excellent assuming standard collider energy and luminosity conditions.Comment: 12 pages, 12 figures. Accepted in Physical Review

    Kinematic study of planetary nebulae in NGC 6822

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    By measuring precise radial velocities of planetary nebulae (which belong to the intermediate age population), H II regions, and A-type supergiant stars (which are members of the young population) in NGC 6822, we aim to determine if both types of population share the kinematics of the disk of H I found in this galaxy. Spectroscopic data for four planetary nebulae were obtained with the high spectral resolution spectrograph Magellan Inamori Kyocera Echelle (MIKE) on the Magellan telescope at Las Campanas Observatory. Data for other three PNe and one H II region were obtained from the SPM Catalog of Extragalactic Planetary Nebulae which employed the Manchester Echelle Spectrometer attached to the 2.1m telescope at the Observatorio Astron\'omico Nacional, M\'exico. In the wavelength calibrated spectra, the heliocentric radial velocities were measured with a precision better than 5-6 km s−1^{-1}. Data for three additional H II regions and a couple of A-type supergiant stars were collected from the literature. The heliocentric radial velocities of the different objects were compared to the velocities of the H i disk at the same position. From the analysis of radial velocities it is found that H II regions and A-type supergiants do share the kinematics of the H I disk at the same position, as expected for these young objects. On the contrary, planetary nebula velocities differ significantly from that of the H I at the same position. The kinematics of planetary nebulae is independent from the young population kinematics and it is closer to the behavior shown by carbon stars, which are intermediate-age members of the stellar spheroid existing in this galaxy. Our results are confirming that there are at least two very different kinematical systems in NGC 6822

    Desarrollo de un Sistema de Cría Artificial para Anastrepha fraterculus (Wied.) (Diptera: Tephritidae)

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    A methodological process is described here to solve two bottle necks that render the establishment of fruit flies under artificial conditions for mass production difficult. The first was the selection of an oviposition system and the second the adaptation to the artificial diet used for larval development. Females preferred to oviposit on yellow spheres, and on white organza cloth flat panels covered with transparent silicon. A larval diet used to rear A.ludens, allowed the highest larval development, survival from egg to larva was 26.9%, larval weight 19.6mg, pupation at 24 h 97.7%, pupal weight 16.7mg and adult emergence 83.3%. Survival curves (nx, 1x) and life expectancy (ex) indicated at least 50% of the adults survive ~40 days. Life expectancy was of 34.74 days. The reproductive rate was 345.38 daughters/mother/generation; the intrinsic rate of population growth was 0.35days-1; while the median generation time and the time of duplication were 16.82 and 20.2 days, respectively. Moreover, we discuss results based on quality control parameters of insects after of 16 generations in mass-rearing under artificial conditions. Se describe el proceso metodológico para solucionar dos cuellos de botella que dificultan el establecimiento de la cría artificial de Anastrepha fraterculus a gran escala. Primero, la selección del sistema de oviposición y segundo la adaptación a la dieta artificial utilizada para el desarrollo larvario. Las hembras tuvieron una mayor preferencia para ovipositar en esferas de color amarillo y en paneles planos elaborados con tela tipo organza de color blanco cubiertos con una película de silicón transparente. Después de evaluar las dietas para el desarrollo larvario de cinco especies de moscas de la fruta, la dieta con la que se obtuvieron los rendimientos más altos correspondió a la dieta ALU (Anastrephaludens), con la cual la supervivencia de huevo a larva fue del 26.9%, peso de larva de 19.6 mg, porcentaje de pupación a las 24 h 97.7%, peso de pupa 16.7 mg y emergencia de adultos de 83.3%. El análisis de las curvas de supervivencia (nx, lx) y la estimación de la expectativa de vida (ex) indicaron que al menos el 50% de los individuos vivieron ~40 días. La expectativa de vida del adulto al momento de la emergencia fue de 38.74 días. La tasa neta de reproducción fue de 345.38 hijas/madre/generación, la tasa intrínseca de crecimiento poblacional fue de 0.35 días-1; mientras que el tiempo medio de generación y el tiempo de duplicación de la población fue de 16.82 y de 20.2 días, respectivamente. Asimismo, se discuten valores de los parámetros de calidad registrados en los insectos luego de 16 generaciones bajocondiciones de cría artificial.

    Coccolithophore biodiversity controls carbonate export in the Southern Ocean

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    Southern Ocean waters are projected to undergo profound changes in their physical and chemical properties in the coming decades. Coccolithophore blooms in the Southern Ocean are thought to account for a major fraction of the global marine calcium carbonate (CaCO3) production and export to the deep sea. Therefore, changes in the composition and abundance of Southern Ocean coccolithophore populations are likely to alter the marine carbon cycle, with feedbacks to the rate of global climate change. However, the contribution of coccolithophores to CaCO3 export in the Southern Ocean is uncertain, particularly in the circumpolar subantarctic zone that represents about half of the areal extent of the Southern Ocean and where coccolithophores are most abundant. Here, we present measurements of annual CaCO3 flux and quantitatively partition them amongst coccolithophore species and heterotrophic calcifiers at two sites representative of a large portion of the subantarctic zone. We find that coccolithophores account for a major fraction of the annual CaCO3 export, with the highest contributions in waters with low algal biomass accumulations. Notably, our analysis reveals that although Emiliania huxleyi is an important vector for CaCO3 export to the deep sea, less abundant but larger species account for most of the annual coccolithophore CaCO3 flux. This observation contrasts with the generally accepted notion that high particulate inorganic carbon accumulations during the austral summer in the subantarctic Southern Ocean are mainly caused by E. huxleyi blooms. It appears likely that the climate-induced migration of oceanic fronts will initially result in the poleward expansion of large coccolithophore species increasing CaCO3 production. However, subantarctic coccolithophore populations will eventually diminish as acidification overwhelms those changes. Overall, our analysis emphasizes the need for species-centred studies to improve our ability to project future changes in phytoplankton communities and their influence on marine biogeochemical cycles.info:eu-repo/semantics/publishedVersio

    Abuse and discrimination towards indigenous people in public health care facilities: experiences from rural Guatemala

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    Background Health inequalities disproportionally affect indigenous people in Guatemala. Previous studies have noted that the disadvantageous situation of indigenous people is the result of complex and structural elements such as social exclusion, racism and discrimination. These elements need to be addressed in order to tackle the social determinants of health. This research was part of a larger participatory collaboration between Centro de Estudios para la Equidad y Gobernanza en los Servicios de Salud (CEGSS) and community based organizations aiming to implement social accountability in rural indigenous municipalities of Guatemala. Discrimination while seeking health care services in public facilities was ranked among the top three problems by communities and that should be addressed in the social accountability intervention. This study aimed to understand and categorize the episodes of discrimination as reported by indigenous communities. Methods A participatory approach was used, involving CEGSS’s researchers and field staff and community leaders. One focus group in one rural village of 13 different municipalities was implemented. Focus groups were aimed at identifying instances of mistreatment in health care services and documenting the account of those who were affected or who witnessed them. All of the 132 obtained episodes were transcribed and scrutinized using a thematic analysis. Results Episodes described by participants ranged from indifference to violence (psychological, symbolic, and physical), including coercion, mockery, deception and racism. Different expressions of discrimination and mistreatment associated to poverty, language barriers, gender, ethnicity and social class were narrated by participants. Conclusions Addressing mistreatment in public health settings will involve tackling the prevalent forms of discrimination, including racism. This will likely require profound, complex and sustained interventions at the programmatic and policy levels beyond the strict realm of public health services. Future studies should assess the magnitude of the occurrence of episodes of maltreatment and racism within indigenous areas and also explore the providers’ perceptions about the problem

    DIAGNOSTICO REPRODUCTIVO DE VACAS DESTINADAS AL SACRIFICIO EN EL RASTRO MUNICIPAL DE CAMOAPA, BOACO

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    La investigación se realizó en el rastro municipal de Camoapa, departamento de Boaco. Los objetivos fueron: Diagnosticar el estado reproductivo y patológico de las vacas destinadas al sacrificio y, proponer estrategias que permitan un adecuado control higiénico sanitario antes y después del proceso de matanza. Se evaluó una muestra de 145 animales (período: tres meses y medio) que equivale al 25 % del total de hembras sacrificadas anualmente. El trabajo consistió en visitar el rastro municipal para realizar el examen clínico general a las vacas que serian sacrificadas, determinando la triada clínica (frecuencias respiratoria, cardiaca y temperatura), revisión de mucosas y condición corporal. También se realizó el diagnóstico reproductivo a través de la palpación rectal el día antes de la matanza, y la observación directa del aparato reproductor, post mortem. También se utilizó un formulario que permitió obtener datos para enriquecer la información. La valoración de los animales evaluados indica que, a este rastro municipal llegan vacas normalmente sanas, sin embargo se encontraron animales con altas frecuencias respiratorias y cardiacas, y elevadas temperaturas. El 48.3 % de las vacas evaluadas resultaron gestadas, encontrándose un máximo de edad fetal de 252 días, faltando pocos días para un posible parto. Las vacas que llegaron vacías, en su mayoría presentaron problemas reproductivos, siendo de mayor relevancia los quistes foliculares en un 30.5%. El 79.3 % de vacas evaluadas, presentaron menos de 4 partos, consideradas como animales jóvenes aptos a la reproducción, coincidiendo con los motivos de descarte reflejados por los productores (problemas reproductivos, económicos y otros). Los resultados permitieron proponer estrategias de mejora en las condiciones de manejo, sobre el control sanitario antes y post mortem, y sobre la higiene general del rastro

    Microalgae Cultivation for Secondary Metabolite Production

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    Microalgae including cyanobacteria have been recognized as an excellent source of fine chemicals, renewable fuels, vitamins, and proteins and usually are found in health food stores around the world. However, the accumulation of these compounds generally occurs at end of the exponential growth phase; furthermore, biomass density in cultivation commonly is low. Open cultures have been used for pigment, biofuels, and biomass production, but these types of culture system are not a good choice for the production of fine chemicals, due to contamination problems and the expensive production costs. Closed photobioreactors can be operated in a continuous cultivation providing an increase on biomass density and contamination-free condition and generally working at a maximum growth rate under specific conditions; besides, these systems can recycle the consumed culture medium at least three times before a new enriched medium is supplied, generating a more cost-effective production system. In addition, microalgae metabolism can be manipulated to provoke a specific secondary metabolite accumulation by the addition of organic carbon source or changing light intensity or both. In other words, photobioreactors can operate in continuous mode, with efficient light supply and the supplementation of organic carbon source to produce fine biochemicals such as anticancer, antibacterial, antioxidant, lectins, antiviral compounds, and biofuels

    Diversity of HLA Class I and Class II blocks and conserved extended haplotypes in Lacandon Mayans.

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    Here we studied HLA blocks and haplotypes in a group of 218 Lacandon Maya Native American using a high-resolution next generation sequencing (NGS) method. We assessed the genetic diversity of HLA class I and class II in this population, and determined the most probable ancestry of Lacandon Maya HLA class I and class II haplotypes. Importantly, this Native American group showed a high degree of both HLA homozygosity and linkage disequilibrium across the HLA region and also lower class II HLA allelic diversity than most previously reported populations (including other Native American groups). Distinctive alleles present in the Lacandon population include HLA-A*24:14 and HLA-B*40:08. Furthermore, in Lacandons we observed a high frequency of haplotypes containing the allele HLA-DRB1*04:11, a relatively frequent allele in comparison with other neighboring indigenous groups. The specific demographic history of the Lacandon population including inbreeding, as well as pathogen selection, may have elevated the frequencies of a small number of HLA class II alleles and DNA blocks. To assess the possible role of different selective pressures in determining Native American HLA diversity, we evaluated the relationship between genetic diversity at HLA-A, HLA-B and HLA-DRB1 and pathogen richness for a global dataset and for Native American populations alone. In keeping with previous studies of such relationships we included distance from Africa as a covariate. After correction for multiple comparisons we did not find any significant relationship between pathogen diversity and HLA genetic diversity (as measured by polymorphism information content) in either our global dataset or the Native American subset of the dataset. We found the expected negative relationship between genetic diversity and distance from Africa in the global dataset, but no relationship between HLA genetic diversity and distance from Africa when Native American populations were considered alone
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