5,214 research outputs found
Efectos de cuatro niveles dietéticos de harina de semilla de chocho (Lupinus mutabilis) sobre parámetros productivos, desarrollo intestinal y valores hematológicos en pavos de ocho semanas
The effect of four dietary levels of lupine seed meal (Lupinus mutabilis, HCH) on growth performance, intestinal tract development and haematological values were evaluated in male turkeys of the one-day BUT line. The turkeys were distributed in four groups with different diets for 56 days: L0 (control) diet without HCH, and L30, L60 and L90 diets containing 30, 60 and 90 g/kg of HCH, respectively. Increased levels of HCH inclusion in the diet, added at the expense of soybean meal, contributed to an increase in fibre concentrations in the experimental diets. Daily feed intake decreased in HCH treatments and feed conversion and bodyweight gain of birds were affected in treatments of 60 and 90 g / kg of HCH inclusion (p<0.05). High dietary levels of HCH led to an increase (p<0.01) of the digesta in the ileum and in the cecum, an increase in the relative tissue mass (p<0.01), as well as a decrease in pH values of the digesta (p<0.01). The increase in HCH in the diet did not alter the haematological values. It is concluded that HCH can be considered as a safe and effective alternative for dietary inclusion at levels of 30 g/kg in starting diets for young turkeys.El efecto de cuatro niveles dietéticos de la harina de semilla de chocho (Lupinus mutabilis, HCH) sobre el rendimiento en crecimiento, desarrollo del tracto intestinal y valores hematológicos fueron evaluados en pavos machos de la línea BUT de un día de edad. Los pavos fueron distribuidos en cuatro grupos con dietas diferentes durante 56 días: dieta L0 (control) sin HCH, y dietas L30, L60 y L90 con 30, 60 y 90 g/kg de HCH, respectivamente. El aumento de los niveles de inclusión de HCH en la dieta, agregados a expensas de la torta de soya, contribuyeron a un aumento en las concentraciones de fibra en las dietas experimentales. La ingesta diaria de alimento disminuyó en los tratamientos de HCH y la conversión alimenticia y el aumento de peso corporal de las aves se vieron afectados en tratamientos de 60 y 90 g/kg de inclusión de HCH (p<0.05). Los niveles dietéticos elevados de HCH llevaron a un aumento (p<0.01) de la digesta en el íleon y en el ciego, a un aumento en la masa relativa del tejido (p<0.01), así como una disminución en los valores de pH de la digesta (p<0.01). El incremento de HCH en la dieta no alteró los valores hematológicos. Se concluye que HCH puede considerarse como una alternativa segura y eficaz de inclusión dietética en niveles de 30 g/kg en dietas de inicio para pavos jóvenes
A Search for Very Active Stars in the Galaxy
We report the first results of a systematic search near the plane of the
Galaxy for the so called very active stars (VAS), which are characterized by a
hard X-ray spectrum and activity in the radio domain. Candidates with hard
X-ray binary-like spectra have been selected from the Bright ROSAT Source
Catalogue in the Zone of Avoidance () and were tentatively
identified in GB6/PMM/NVSS radio surveys. Most of them were observed with the
ATCA and VLA. Precise radio coordinates have led to unambiguous optical
identification for 60 candidates, and a sub-sample of five of themhas been
observed with the VLT. Also some discovery and confirmatory spectra were
obtained with the AAT (4-m) and BTA (6-m). Spectroscopy with moderate
dispersion, made with the FORS1 spectrograph of the VLT has revealed two
stellar objects (one of them, VASC J1628-41, is definitivelya binary VAS), one
new AGN and two featureless spectrum sources. One of these objects, VASC
J1353-66, shows a marginal evidence of proper motion, which, if confirmed,
would imply the discovery of a new type of galactic source.Comment: to appear in A&A, 7 figure
3.9 day orbital modulation in the TeV gamma-ray flux and spectrum from the X-ray binary LS 5039
New observations of LS 5039, a High Mass X-ray Binary comprising a massive
star and compact object, were carried out with the High Energy Stereoscopic
System of Cherenkov Telescopes (H.E.S.S.) in 2005 at very high energy (VHE)
gamma-ray energies. These observations reveal that its flux and energy spectrum
are modulated with the 3.9 day orbital period of the binary system. This is the
first time in gamma-ray astronomy that orbital modulation has been observed,
and periodicity clearly established using ground-based gamma-ray detectors. The
VHE gamma-ray emission is largely confined to half of the orbit, peaking around
the inferior conjunction epoch of the compact object. For this epoch, there is
also a hardening of the energy spectrum in the energy range between 0.2 TeV and
a few TeV. The flux vs. orbital phase profile provides the first clear
indication of gamma-ray absorption via pair production within an astrophysical
source, a process which is expected to occur if the gamma-ray production site
is situated within ~1 AU of the compact object. Moreover the production region
size must be not significantly greater than the binary separation (~0.15 AU).
Notably, these constraints are also considerably smaller than the collimated
outflows or jets (extending out to ~1000 AU) observed in LS 5039. The spectral
hardening could arise from variations with phase in the maximum electron
energies, and/or the dominant VHE gamma-ray production mechanism.Comment: 8 pages, 8 figures, accepted for publication in Astronomy &
Astrophysic
Young starless cores embedded in the magnetically dominated Pipe Nebula
The Pipe Nebula is a massive, nearby dark molecular cloud with a low
star-formation efficiency which makes it a good laboratory to study the very
early stages of the star formation process. The Pipe Nebula is largely
filamentary, and appears to be threaded by a uniform magnetic field at scales
of few parsecs, perpendicular to its main axis. The field is only locally
perturbed in a few regions, such as the only active cluster forming core B59.
The aim of this study is to investigate primordial conditions in low-mass
pre-stellar cores and how they relate to the local magnetic field in the cloud.
We used the IRAM 30-m telescope to carry out a continuum and molecular survey
at 3 and 1 mm of early- and late-time molecules toward four selected starless
cores inside the Pipe Nebula. We found that the dust continuum emission maps
trace better the densest regions than previous 2MASS extinction maps, while
2MASS extinction maps trace better the diffuse gas. The properties of the cores
derived from dust emission show average radii of ~0.09 pc, densities of
~1.3x10^5 cm^-3, and core masses of ~2.5 M_sun. Our results confirm that the
Pipe Nebula starless cores studied are in a very early evolutionary stage, and
present a very young chemistry with different properties that allow us to
propose an evolutionary sequence. All of the cores present early-time molecular
emission, with CS detections toward all the sample. Two of them, Cores 40 and
109, present strong late-time molecular emission. There seems to be a
correlation between the chemical evolutionary stage of the cores and the local
magnetic properties that suggests that the evolution of the cores is ruled by a
local competition between the magnetic energy and other mechanisms, such as
turbulence.Comment: Accepted for publication in ApJ. 15 pages, 5 figures, 9 table
Hierarchical Stellar Structures in the Local Group Dwarf Galaxy NGC 6822
We present a comprehensive study of the star cluster population and the
hierarchical structure in the clustering of blue stars with ages <~ 500 Myr in
the Local Group dwarf irregular galaxy NGC 6822. Our observational material
comprises the most complete optical stellar catalog of the galaxy from imaging
with the Suprime-Cam at the 8.2-m SUBARU Telescope. We identify 47 distinct
star clusters with the application of the nearest-neighbor density method to
this catalog for a detection threshold of 3sigma above the average stellar
density. The size distribution of the detected clusters can be very well
approximated by a Gaussian with a peak at ~ 68 pc. Their cluster mass function
is fitted very well by a power-law with index alpha ~ 1.5 +/- 0.7, consistent
with other Local Group galaxies and the cluster initial mass function. The
application of the nearest-neighbor density method for various density
thresholds, other than 3sigma, enabled the identification of stellar
concentrations in various length-scales. The stellar density maps constructed
with this technique provide a direct proof of hierarchically structured stellar
concentrations in NGC 6822. We illustrate this hierarchy by the so-called
"dendrogram" of the detected stellar structures, which demonstrates that most
of the detected structures split up into several substructures over at least
three levels. We quantify the hierarchy of these structures with the use of the
minimum spanning tree method. The morphological hierarchy in stellar
clustering, which we observe in NGC 6822 resembles that of the turbulent
interstellar matter, suggesting that turbulence on pc- and kpc-scales has been
probably the major agent that regulated clustered star formation in NGC 6822.Comment: 18 pages in ApJ two-column format, 13 figure
Transcriptional analysis of temporal gene expression in germinating Clostridium difficile 630 endospores.
Clostridium difficile is the leading cause of hospital acquired diarrhoea in industrialised countries. Under conditions that are not favourable for growth, the pathogen produces metabolically dormant endospores via asymmetric cell division. These are extremely resistant to both chemical and physical stress and provide the mechanism by which C. difficile can evade the potentially fatal consequences of exposure to heat, oxygen, alcohol, and certain disinfectants. Spores are the primary infective agent and must germinate to allow for vegetative cell growth and toxin production. While spore germination in Bacillus is well understood, little is known about C. difficile germination and outgrowth. Here we use genome-wide transcriptional analysis to elucidate the temporal gene expression patterns in C. difficile 630 endospore germination. We have optimized methods for large scale production and purification of spores. The germination characteristics of purified spores have been characterized and RNA extraction protocols have been optimized. Gene expression was highly dynamic during germination and outgrowth, and was found to involve a large number of genes. Using this genome-wide, microarray approach we have identified 511 genes that are significantly up- or down-regulated during C. difficile germination (p≤0.01). A number of functional groups of genes appeared to be co-regulated. These included transport, protein synthesis and secretion, motility and chemotaxis as well as cell wall biogenesis. These data give insight into how C. difficile re-establishes its metabolism, re-builds the basic structures of the vegetative cell and resumes growth
Challenges in context-aware mobile language learning: the MASELTOV approach
Smartphones, as highly portable networked computing devices with embedded sensors including GPS receivers, are ideal platforms to support context-aware language learning. They can enable learning when the user is en-gaged in everyday activities while out and about, complementing formal language classes. A significant challenge, however, has been the practical implementation of services that can accurately identify and make use of context, particularly location, to offer meaningful language learning recommendations to users. In this paper we review a range of approaches to identifying context to support mobile language learning. We consider how dynamically changing aspects of context may influence the quality of recommendations presented to a user. We introduce the MASELTOV project’s use of context awareness combined with a rules-based recommendation engine to present suitable learning content to recent immigrants in urban areas; a group that may benefit from contextual support and can use the city as a learning environment
Multidetector cardiac tomography: A useful tool before cardiac resynchronization therapy
Background: Left ventricular lead placement in a suitable coronary vein is a key determinant of responsiveness to cardiac resynchronization therapy (CRT). Multidetector cardiac tomography (MDCT) is a non-invasive alternative to depict cardiac venous anatomy although coronary sinus (CS) retrograde venography (RV) is the gold standard. The aim of this study was to evaluate the accuracy of MDCT to determine the presence of CS tributaries before CRT.
Methods: A retrospective analysis of 41 consecutive patients eligible to CRT was performed. MDCT was assessed in all patients before CRT and RV was achieved in 39 patients. Both methods evaluated the presence of the inferior interventricular vein (IIV), posterior vein (PV) and lateral main vein (LMV). CS ostium diameter and distance between the CS ostium and right atrium (RA) lateral wall were also measured.
Results: The IIV was identified in 100% of MDCT and in 43.6% of RV. In comparison to RV, the MDCT’s sensitivity to identify PV and LMV was 100% for both, kappa coefficient of 0.792 (CI 95% 0.46–0.93) and 0.69 (CI 95% 0.46–0.91), respectively. There was no significant difference between ischemic and non-ischemic patients regarding the presence of PV or LMV. Median CS antero-posterior diameter was 10.3 mm (IQR 7.5–13) and supero-inferior was 14.1 mm (IQR 11.5–17) (p < 0.01). A positive correlation (p < 0.001) between echocardiographic RA area and the distance from CS ostium to the RA lateral wall in the MDCT was observed.
Conclusions: MDCT is as accurate as RV to depict CS and its tributaries (IIV, PV, LMV), and it could be useful as a non-invasive technique before CRT
ASTRIS: A real world treatment study of osimertinib in patients (pts) with EGFR T790M-positive non-small cell lung cancer (NSCLC) - European subset
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