632 research outputs found
The Non-thermal Radio Jet Toward the NGC 2264 Star Formation Region
We report sensitive VLA 3.6 cm radio observations toward the head of the Cone
nebula in NGC 2264, made in 2006. The purpose of these observations was to
study a non-thermal radio jet recently discovered, that appears to emanate from
the head of the Cone nebula. The jet is highly polarized, with well-defined
knots, and one-sided. The comparison of our images with 1995 archive data
indicates no evidence of proper motions nor polarization changes. We find
reliable flux density variations in only one knot, which we tentatively
identify as the core of a quasar or radio galaxy. An extragalactic location
seems to be the best explanation for this jet.Comment: 12 pages, 5 figure
Regulon-Specific Control of Transcription Elongation across the Yeast Genome
Transcription elongation by RNA polymerase II was often considered an invariant non-regulated process. However, genome-wide studies have shown that transcriptional pausing during elongation is a frequent phenomenon in tightly-regulated metazoan genes. Using a combination of ChIP-on-chip and genomic run-on approaches, we found that the proportion of transcriptionally active RNA polymerase II (active versus total) present throughout the yeast genome is characteristic of some functional gene classes, like those related to ribosomes and mitochondria. This proportion also responds to regulatory stimuli mediated by protein kinase A and, in relation to cytosolic ribosomal-protein genes, it is mediated by the silencing domain of Rap1. We found that this inactive form of RNA polymerase II, which accumulates along the full length of ribosomal protein genes, is phosphorylated in the Ser5 residue of the CTD, but is hypophosphorylated in Ser2. Using the same experimental approach, we show that the in vivo–depletion of FACT, a chromatin-related elongation factor, also produces a regulon-specific effect on the expression of the yeast genome. This work demonstrates that the regulation of transcription elongation is a widespread, gene class–dependent phenomenon that also affects housekeeping genes
Seroprevalence of Neospora caninum infection in cattle from Pereira, Colombia
There are over 25.6 million cattle heads in Colombia being the fourth-highest herd in Latin America. This study aimed to describe the seroprevalence of Neospora caninum in cattle from 25 rural farms at Pereira municipality, Risaralda Department, which has a total bovine population of 43,508 animals. A cross-sectional observational study was performed in beef and dairy herds during 2017–2018. A total of 325 animals in 25 herds, with 13 animals per herd, were sampled. A commercial competitive ELISA (cELISA) kit was used to detect N. caninum antibodies. Associated risk factors were analyzed in two different levels: individual animals and herds. For all the independent variables, chi-square (χ2) and Fisher tests were used to assess associations and significance. The overall estimated seropositivity was 20.6% (95%CI 16.2%–25.0%). The seroprevalence by herds was 92.0% ranging from 0.0% to 46.2%. Noteworthy, beef herds had significantly (p = 0.0107) higher seropositivity (50% of them above 35% of seropositivity) compared with those for milk purposes (4.8%) (OR = 20.0; 95%CI 1.2–331.0). Other risk factors were not significantly (p ≥ 0.05) associated with N. caninum seropositivity. Bovine neosporosis may be associated with abortions in both beef and dairy Colombian farms. More studies about the epidemiology, associated factors and consequences, as well as on tools for better diagnosis of bovine abortion, including histopathology and other ancillary tests, should be performed.Fil: Idarraga Bedoya, Samuel E.. Fundación Universitaria Autónoma de las Américas. Facultad de Medicina Veterinaria y Zootecnia; ColombiaFil: Álvarez Chica, Jaime. Fundación Universitaria Autónoma de las Américas. Facultad de Medicina Veterinaria y Zootecnia; ColombiaFil: Bonilla Aldana, D. Katterine. Universidad Tecnológica de Pereira; Colombia. Fundación Universitaria Autónoma de las Américas; ColombiaFil: Moore, Dadin Prando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Innovación para la Producción Agropecuaria y el Desarrollo Sostenible - Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce. Instituto de Innovación para la Producción Agropecuaria y el Desarrollo Sostenible; ArgentinaFil: Rodríguez Morales, Alfonso J.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Innovación para la Producción Agropecuaria y el Desarrollo Sostenible - Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce. Instituto de Innovación para la Producción Agropecuaria y el Desarrollo Sostenible; Argentina. Universidad Tecnológica de Pereira; Colombia. Fundación Universitaria Autónoma de las Américas; Colombi
Cocirculation and Coinfection Associated to Zika Virus in the Americas
Zika virus, a flavivirus, has arrived to Latin America in 2013. It became evident causing epidemics since 2015, first in Brazil and later in other countries in the region, such as Colombia, with a higher peak in 2016. The World Health Organization (WHO), based on cumulated evidence on its association with Guillain-Barre syndrome (GBS) and microcephaly and other birth defects (also the congenital Zika syndrome, CZS), declared for a period of almost a year, an international public health emergency. Epidemics in the region caused around 1 million cases with also additional complications beyond GBS and the CZS, which in patients with comorbidities lead to deaths. Among the events studied in the region, a number of cases with arboviral coinfections/codetection (dengue and chikungunya) were described and published beginning in Colombia and later in Brazil. In addition to that, cocirculation and still ongoing research on antibody-dependent enhancement (ADE) are challenges for physicians and public health authorities, given the implications for clinical manifestations and serological diagnosis in patients with previous exposition to other flaviviruses. We reviewed such aspects in this chapter
Chikungunya en las Américas : Preparación, vigilancia y alerta en Chile
Actualmente los gobiernos del continente americano se encuentran en alerta sanitaria por el incremento sostenido de casos de la fiebre Chikungunya.EPIDEMIOLOG
Assessment of discretely measured indicators and maximum daily trunk shrinkage for detecting water stress in pomegranate trees
Measurements obtained by the continuous monitoring of trunk diameter fluctuations were comparedwith discrete measurements of midday stem water potential and midday leaf conductance (gl)in adult pomegranate trees (Punica granatum L. cv. Mollar de Elche). Control plants (T0) were irrigateddaily above their crop water requirements in order to attain non-limiting soil water conditions in 2009 and 2010, while T1 plants were subjected to water stress by depriving them of irrigation water for34 days in 2010, after which time irrigation was restored and plant recovery was studied for 7 days.T1 plants showed a substantial degree of water stress, which developed slowly. Maximum daily trunkshrinkage (MDS) was identified to be the most suitable plant-based indicator for irrigation scheduling inadult pomegranate trees, because its signal:noise ((T1/T0):coefficient of variation) ratio was higher thanthat for midday stem water potential((T1/T0):coefficient of variation) and gl((T0/T1):coefficient of variation). MDS increasedin response to water stress, but when the stemfell below ¿1.67 MPa, the MDS values decreased. Fornon-limiting water conditions, MDS could be predicted from mean daily air temperature (Tm) throughexponential equations fitted to pooled data across several seasons. First-order equations were alsoobtained by pooling data across several seasons to predict MDS from crop reference evapotranspira-tion (ETo), mean daily air vapour pressure deficit (VPDm), Tmand solar radiation (Rs), but these should beused only within a certain range of values (ETo, 2.1¿7.4 mm; VPDm, 0.64¿2.96 kPa; Tm, 12.1¿28.3¿C; Rs,119.4¿331.3 Wm¿2). Hence, automated MDS measurements have the potential to be used in irrigationscheduling of pomegranate, and these values can be normalized to non-limiting water conditions bylocally derived empirical relationships with meteorological variables.Ministerio de Ciencia e Innovación (CICYT/FEDER) AGL2010-19201-C04-01AGRAgencia Española de Cooperación Internacional para el Desarrollo (AECID
Zoogeografía de los gastrópodos terrestres del sur de Nuevo León, México
The terrestrial gastropods of the southern region of the state of Nuevo León were surveyed (december, 2001 – december, 2004). Samples were obtained from 35 localities, in differents vegetational types. The primary zoogeographical relationships are characterized by the presence of the endemics (34 species or subspecies: 40.48%, high value in northeastern México), those of neotropical and neartic affinities (27 species: 32.14%) and those exhibiting panamerican distributions (13 species: 15.48%). The three families with the largest number of endemic species (or subspecies) are the Spiraxidae and Urocoptidae (both with eight species), and the Humboldtianidae (five species). The vegetational types with the greatest biogeographical values are the gallery forest and pine forest. The highest values of malacofaunal similarities are between the submountain shrubs and savannah cultivation and also between the oak-pine forest and gallery forest.Se estudiaron (diciembre de 2001 a diciembre de 2004) los gastrópodos terrestres de la región sur del estado Nuevo León. Las muestras fueron obtenidas en 35 localidades, en diferentes tipos de vegetación. Las principales afinidades zoogeográficas son el endemismo de 34 especies o subespecies (40.48% de la malacofauna, valor alto en el noreste de México), la neotropical principalmente y neártica de 27 especies (32.14%) y la distribución panamericana de 13 especies (15.48%). Las familias con mayor número de especies o subespecies endémicas son Spiraxidae y Urocoptidae, ambas con ocho, y Humboldtianidae con cinco. Los mayores valores biogeográficos de la malacofauna terrestre se presentaron en la vegetación de galería y en el bosque de pino. Las mayores similitudes malacofaunísticas se observan entre el matorral submontano y el pastizal cultivado y entre el bosque de pino-encino y la vegetación de galería
Effect of the Ni and Sn impregnation in the microstructural and textural properties of SnO nanoparticles
En este trabajo se estudió la síntesis y la caracterización de SnO y el efecto que tiene el Ni y Sn, al ser 2
incorporados a la estructura del SnO por impregnación. La obtención del SnO se realizó utilizando el 2 2
método de precipitación controlada y el Sn y el Ni se adicionaron empleando el método de impregnación.
Las técnicas TEM, EDX, XRD y área superficial se usaron para caracterizar los sólidos preparados. Se
encontró que la impregnación con Ni conlleva a la formación de soluciones sólidas sustitucionales, dentro
del rango de dopado empleado (hasta 3% en moles), y segregación sobre la superficie de las partículas de
SnO , lo que explica los efectos generados sobre las propiedades texturales del SnO
Procedimiento para el diseño de un sistema de calentamiento solar-mixto de aire que utiliza agua como fluido de trabajo
En este artículo se describe un sistema solar-mixto de calefacción de aire que incorpora colectores planos calentadores del agua, un tanque acumulador de calor y un dispositivo para el intercambio de calor agua-aire. Se presentan los ensayos que determinaron la disposición óptima del equipo para el intercambio de calor con flujo de agua por termosifón y el comportamiento térmico para diferentes flujos de aire, así como los ensayos para conocer el comportamiento del sistema de calentamiento solar de agua. Finalmente, el diseño se efectúa mediante un programa de computador adaptado para tal fin
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