2,504 research outputs found
Accretion disk in the eclipsing binary AU Mon
We analyze the CoRoT and V-passband ground-based light curves of the
interacting close binary AU Mon, assuming that there is a geometrically and
optically thick accretion disk around the hotter and more massive star, as
inferred from photometric and spectroscopic characteristics of the binary. Our
model fits the observations very well and provides estimates for the orbital
elements and physical parameters of the components and of the accretion disk.Comment: Accepted for publication in MNRA
Estimation of mean number of daily hand hygiene procedures per patient can represent an effective and easy understandable method to evaluate adherence. Experience in a tertiary care pediatric hospital of Northern Italy
Introduction. Hand decontamination with alcohol-based antiseptic agents is considered the best practise to reduce healthcare associated infections.Methods. We present a new method to monitor hand hygiene, introduced in a tertiary care pediatric hospital inNorthern Italy, which estimates the mean number of daily hand decontamination procedures performed per patient. The total amount of isopropyl alcohol and chlorhexydine solution supplied in a trimester to each hospital ward was put in relation with the number of hospitalization days, and expressed as liters/1000 hospitalization-days (World Health Organization standard), and the mean number of patients hospitalized and expressed as mean estimated number of hand hygiene procedures per patient per day (new method).Results. The two methods had similar performance for estimating the adherence to correct hand disinfection procedures. The new method identified wards and/or periods with high or low adherence to the procedure and indicated where to perform interventions and their effectiveness. The new methods could result easy-to understand also for non-infection control experts.Conclusion. This method can help non-infection control experts to understand adherence to correct hand- hygiene procedures and improve quality standards
Temporal integration for amplitude modulation in childhood: Interaction between internal noise and memory
It is still unclear whether the gradual improvement in amplitude-modulation (AM) sensitivity typically found in children up to 10 years of age reflects an improvement in “processing efficiency” (the central ability to use information extracted by sensory mechanisms). This hypothesis was tested by evaluating temporal integration for AM, a capacity relying on memory and decision factors. This was achieved by measuring the effect of increasing the number of AM cycles (2 vs 8) on AM-detection thresholds for three groups of children aged from 5 to 11 years and a group of young adults. AM-detection thresholds were measured using a forced-choice procedure and sinusoidal AM (4 or 32 Hz rate) applied to a 1024-Hz pure-tone carrier. All age groups demonstrated temporal integration for AM at both rates; that is, significant improvements in AM sensitivity with a higher number of AM cycles. However, an effect of age is observed as both 5–6 year olds and adults exhibited more temporal integration compared to 7–8 and 10–11 year olds at both rates. This difference is due to: (i) the 5–6 year olds displaying the worst thresholds with 2 AM cycles, but similar thresholds with 8 cycles compared to the 7–8 and 10–11 year olds, and, (ii) adults showing the best thresholds with 8 AM cycles but similar thresholds with 2 cycles compared to the 7–8 and 10–11 year olds. Computational modelling indicated that higher levels of internal noise combined with poorer short-term memory capacities in children accounted for the developmental trends. Improvement in processing efficiency may therefore account for the development of AM detection in childhood
Cuticular hydrocarbons as cues of sex and health condition in Polistes dominula wasps
International audienceIn the paper wasp Polistes dominula, cuticular hydrocarbons play a critical role 14 to acquire information regarding conspecific individuals. However, the relationship 15 between cuticular hydrocarbons, health status and male sexually selected traits is poorly 16 investigated. In this study, we characterized the cuticular hydrocarbon profile of adult 17 male and female wasps, infected or not by the strepsipteran endoparasite Xenos 18 vesparum, to assess whether the chemical signature provides information about sex and 19 health status (parasite infection). Moreover, we tested whether the chemical profile 20 reflects male quality as measured via morphological and behavioural (sexually 21 selected) traits at leks. Our results showed that males and females had similar total 22 amount of CHCs, quantitatively different profiles and, to a lesser extent, sex specific 23 chemical compounds. Cuticular profiles were influenced by the strepsipteran infection
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High-speed X-Ray Phase-Contrast Imaging of String Cavitation in an Enlarged Diesel-Injector Orifice Replica
The present investigation illustrates the temporally-resolved, phase-contrast visualization of the cavitating flowwithin an enlarged injector replica conducted at the ANL Advanced Photon Source. The flow was captured through side-view, x-ray radiographies at 67890 frames per second with an exposure time of 347ns. The orifice employed for the experiments has an internal diameter of 1.5mm and length equal to 5mm. A parametric investigation was conducted considering various combinations of the Reynolds and cavitation numbers, which designate the extent of in-nozzle cavitation. Proper post-processing of the obtained radiographies enabled the extraction of information regarding the shape and dynamical behaviour of cavitating strings. The average string extent along with its standard deviation was calculated for the entire range of conditions examined (Re=18000-36000, CN=1.6-7.7). Furthermore, the effect of the prevailing flow conditions on quantities indicative of the string dynamic behaviour such as the break-up frequency and lifetime was characterized and the local velocity field in the string region was obtained
The outer halos of elliptical galaxies
Recent progress is summarized on the determination of the density
distributions of stars and dark matter, stellar kinematics, and stellar
population properties, in the extended, low surface brightness halo regions of
elliptical galaxies. With integral field absorption spectroscopy and with
planetary nebulae as tracers, velocity dispersion and rotation profiles have
been followed to ~4 and ~5-8 effective radii, respectively, and in M87 to the
outer edge at ~150 kpc. The results are generally consistent with the known
dichotomy of elliptical galaxy types, but some galaxies show more complex
rotation profiles in their halos and there is a higher incidence of
misalignments, indicating triaxiality. Dynamical models have shown a range of
slopes for the total mass profiles, and that the inner dark matter densities in
ellipticals are higher than in spiral galaxies, indicating earlier assembly
redshifts. Analysis of the hot X-ray emitting gas in X-ray bright ellipticals
and comparison with dynamical mass determinations indicates that non-thermal
components to the pressure may be important in the inner ~10 kpc, and that the
properties of these systems are closely related to their group environments.
First results on the outer halo stellar population properties do not yet give a
clear picture. In the halo of one bright galaxy, lower [alpha/Fe] abundances
indicate longer star formation histories pointing towards late accretion of the
halo. This is consistent with independent evidence for on-going accretion, and
suggests a connection to the observed size evolution of elliptical galaxies
with redshift.Comment: 8 pages. Invited review to appear in the proceedings of "Galaxies and
their Masks" eds. Block, D.L., Freeman, K.C. & Puerari, I., 2010, Springer
(New York
Oms1 associates with cytochrome c oxidase assembly intermediates to stabilize newly synthesized Cox1.
The mitochondrial cytochromecoxidase assembles in the inner membrane from subunits of dual genetic origin. The assembly process of the enzyme is initiated by membrane insertion of the mitochondria-encoded Cox1 subunit. During complex maturation, transient assembly intermediates, consisting of structural subunits and specialized chaperone-like assembly factors, are formed. In addition, cofactors such as heme and copper have to be inserted into the nascent complex. To regulate the assembly process, the availability of Cox1 is under control of a regulatory feedback cycle, in which translation of the COX1 mRNA is stalled when assembly intermediates of Cox1 accumulate through inactivation of the translational activator Mss51. Here we have isolated a cytochromecoxidase assembly intermediate in preparatory scale fromcoa1Δmutant cells using Mss51 as a bait. We demonstrate that at this stage of assembly the complex has not yet incorporated the heme a cofactors. Using quantitative mass spectrometry, we defined the protein composition of the assembly intermediate and unexpectedly identified the putative methyltransferase Oms1 as a constituent. Our analyses show that Oms1 participates in cytochromecoxidase assembly by stabilizing newly synthesized Cox1
Reweighting NNPDFs: the W lepton asymmetry
We present a method for incorporating the information contained in new
datasets into an existing set of parton distribution functions without the need
for refitting. The method involves reweighting the ensemble of parton densities
through the computation of the chi-square to the new dataset. We explain how
reweighting may be used to assess the impact of any new data or pseudodata on
parton densities and thus on their predictions. We show that the method works
by considering the addition of inclusive jet data to a DIS+DY fit, and
comparing to the refitted distribution. We then use reweighting to determine
the impact of recent high statistics lepton asymmetry data from the D0
experiment on the NNPDF2.0 parton set. We find that the D0 inclusive muon and
electron data are perfectly compatible with the rest of the data included in
the NNPDF2.0 analysis and impose additional constraints on the large-x d/u
ratio. The more exclusive D0 electron datasets are however inconsistent both
with the other datasets and among themselves, suggesting that here the
experimental uncertainties have been underestimated.Comment: 36 pages, 22 figures: errors in Eqns.12,36,37 corrected and parts of
Figs.1,6,10,13,15,19 replace
Avaliação de clones de mandioca visando o processamento industrial em Dourados, MS.
Publicado também na: RAT: Revista Raízes e Amidos Tropicais, v. 3, 2007. (SEP 036)
Mitochondrial protein synthesis adapts to influx of nuclear-encoded protein.
Mitochondrial ribosomes translate membrane integral core subunits of the oxidative phosphorylation system encoded by mtDNA. These translation products associate with nuclear-encoded, imported proteins to form enzyme complexes that produce ATP. Here, we show that human mitochondrial ribosomes display translational plasticity to cope with the supply of imported nuclear-encoded subunits. Ribosomes expressing mitochondrial-encoded COX1 mRNA selectively engage with cytochrome c oxidase assembly factors in the inner membrane. Assembly defects of the cytochrome c oxidase arrest mitochondrial translation in a ribosome nascent chain complex with a partially membrane-inserted COX1 translation product. This complex represents a primed state of the translation product that can be retrieved for assembly. These findings establish a mammalian translational plasticity pathway in mitochondria that enables adaptation of mitochondrial protein synthesis to the influx of nuclear-encoded subunits
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