1,604 research outputs found
High Energy Cosmic Rays from Neutrinos
We discuss recent models in which neutrinos, which are assumed to have mass
in the eV range, originate the highest energy cosmic rays by interaction with
the enhanced density in the galactic halo of the relic cosmic neutrino
background. We make an analytical calculation of the required neutrino fluxes
to show that the parameter space for these models is constrained by horizontal
air shower searches and by the total number of background neutrinos, so that
only models which have fairly unnatural halo sizes and enhanced densities are
allowed.Comment: 14 pages, 3 ps figures. To appear in Phys. Rev.
Increasing trend in the prevalence of morbid obesity in Spain: from 1.8 to 6.1 per thousand in 14 years
Obesity, and especiallymorbid obesity, increases the risk of cardiovascular as well as non-cardiovascular
diseases. Our objective was to ascertain the trends in morbid obesity in Spain from 1993 to 2006 using
representative data from 106,048 participants in the National Health Surveys. An age-adjusted Poisson
regression model stratified by sex was fitted using morbid obesity as the dependent variable.
An increasing trend in prevalent morbid obesity from 1.8 to 6.1 per thousand participants was found
(increase > 200%). Morbid obesity prevalence was higher in women. After adjusting for age, a
monotonically increasing prevalence of morbid obesity was apparent for both men and women: the
relative increase was 4% per year in women and 12% per year in men. These trends highlight the
importance of preventive actions
Validation of metabolic syndrome using medical records in the SUN cohort
The objective of this study was to evaluate the validity of self
reported criteria of Metabolic Syndrome (MS) in the SUN (Seguimiento Universidad
de Navarra) cohort using their medical records as the gold standard. METHODS: We
selected 336 participants and we obtained MS related data according to Adult
Treatment Panel III (ATP III) and International Diabetes Federation (IDF). Then
we compared information on the self reported diagnosis of MS and MS diagnosed in
their medical records. We calculated the proportion of confirmed MS, the
proportion of confirmed non-MS and the intraclass correlation coefficients for
each component of the MS. RESULTS: From those 336 selected participants, we
obtained sufficient data in 172 participants to confirm or reject MS using ATP
III criteria. The proportion of confirmed MS was 91.2% (95% CI: 80.7- 97.1) and
the proportion of confirmed non-MS was 92.2% (95% CI: 85.7-96.4) using ATP III
criteria. The proportion of confirmed MS using IDF criteria was 100% (95% CI:
87.2-100) and the proportion of confirmed non-MS was 97.1% (95% CI: 85.1-99.9).
Kappa Index was 0.82 in the group diagnosed by ATP III criteria and 0.97 in the
group diagnosed by IDF criteria. Intraclass correlation coefficients for the
different component of MS were: 0.93 (IC 95%:0.91- 0.95) for BMI; 0.96 (IC 95%:
0.93-0.98) for waist circumference; 0.75 (IC 95%: 0.66-0.82) for fasting glucose;
0.50 (IC 95%:0.35-0.639) for HDL cholesterol; 0.78 (IC 95%: 0.70-0.84) for
triglycerides; 0.49 (IC 95%:0.34-0.61) for systolic blood pressure and 0.55 (IC
95%: 0.41-0.65) for diastolic blood pressure. CONCLUSIONS: Self-reported MS based
on self reported components of the SM in a Spanish cohort of university graduates
was sufficiently valid as to be used in epidemiological studies
Optimization of the design of OMNIS, the observatory of multiflavor neutrinos from supernovae
A Monte Carlo code has been developed to simulate the operation of the
planned detectors in OMNIS, a supernova neutrino observatory. OMNIS will detect
neutrinos originating from a core collapse supernova by the detection of
spalled neutrons from Pb- or Fe-nuclei. This might be accomplished using
Gd-loaded liquid scintillator. Results for the optimum configuration for such
modules with respect to both neutron detection efficiency and cost efficiency
are presented. Careful consideration has been given to the expected levels of
radioactive backgrounds and their effects. The results show that the amount of
data to be processed by a software trigger can be reduced to the <10kHz region
and a neutron, once produced in the detector, can be detected and identified
with an efficiency of >30%.Comment: Elsevier preprint; 29 pages, 23 figure
A biomarker of myocardial fibrosis predicts long-term response to cardiac resynchronization therapy
Staff training influence on non-invasive ventilation outcome for acute hypercapnic respiratory failure
Background. Although non-invasive ventilation (NIV) efficacy in the treatment of acute hypercapnic respiratory failure (AHRF) have been previously demonstrated, not all the studies reveal this fact in the same degree, with some variability in the results. This study aimed to analyse variables related to NIV outcome for AHRF. Methods. A group of consecutive patients requiring NIV due to AHRF were included in a prospective observational cohort study performed in conventional wards. Variables considered included those reported in the literature, as well as staff problems during the management of the ventilators. The study aimed to include all patients during one year, but after the initial results, it had to be suspended. Results. Fifteen patients were included in the study: 10 males, mean age 68 ± 12. APACHE-II score was 17.6 ± 6.5. pH and pCO2 before NIV were 7.22 ± 0.11 and 110 ± 72 mmHg respectively. pH, corticosteroids use, APACHE score, and EPAP were found to influence outcome. Besides, an inadequate use of NIV due to lack of personnel training was detected in all patients with NIV failure (RR 3.5; 95% CI: 1.08-11.2; p = 0.007). In the light of these results, the study had to be suspended and patients were transferred to the respiratory ward. Conclusions. NIV is a life-saving respiratory treatment influenced by several factors, of which staff training is a key one. Centres attending acute respiratory patients should have an area in which this requirement is fulfilled
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A Stochastic Frontier Model to Determine Technical Efficiency of the Purse Seine Fishery in the Gulf of Cadiz (Spain)
In this paper we analyse different econometric procedures of technical efficiency to estimate fishing capacity. These procedures are then applied to the purse seine fishery located in the Gulf of Cádiz. The target species of this fishery has changed quite a lot over the past few years. It used to be mackerel (Scomber spp.). Afterwards, it was anchovy (Engraulis encrasicholus) and, recently, sardine (Sardina pilchardus). The regulation of anchovy and sardine fisheries by European Union is only based on Total Allowable Catch for vessels which are longer than 10 metres. This management measure could be unsuitable in this fishery for two reasons. Firstly, most of the vessels measure less than 10 metres and, secondly, there is a small interrelation between vessel efficiency and length.Keywords: purse seine fishing, Stochastic frontiers, Theoretical and Empirical Bio-Economic Modelling, panel data, Fisheries Economics, Fishing capacity, Gulf of Cadiz, management policie
Status of four-neutrino mass schemes: a global and unified approach to current neutrino oscillation data
We present a unified global analysis of neutrino oscillation data within the
framework of the four-neutrino mass schemes (3+1) and (2+2). We include all
data from solar and atmospheric neutrino experiments, as well as information
from short-baseline experiments including LSND. If we combine only solar and
atmospheric neutrino data, (3+1) schemes are clearly preferred, whereas
short-baseline data in combination with atmospheric data prefers (2+2) models.
When combining all data in a global analysis the (3+1) mass scheme gives a
slightly better fit than the (2+2) case, though all four-neutrino schemes are
presently acceptable. The LSND result disfavors the three-active neutrino
scenario with only and at 99.9% CL with
respect to the four-neutrino best fit model. We perform a detailed analysis of
the goodness of fit to identify which sub-set of the data is in disagreement
with the best fit solution in a given mass scheme.Comment: 32 pages, 8 Figures included, REVTeX4.Improved discussion in sec. XI,
references added, version accepted by Phys. Rev.
The effect of spontaneous collapses on neutrino oscillations
We compute the effect of collapse models on neutrino oscillations. The effect
of the collapse is to modify the evolution of the `spatial' part of the wave
function, which indirectly amounts to a change on the flavor components. In
many respects, this phenomenon is similar to neutrino propagation through
matter. For the analysis we use the mass proportional CSL model, and perform
the calculation to second order perturbation theory. As we will show, the CSL
prediction is very small - mainly due to the very small mass of neutrinos - and
practically undetectable.Comment: 24 pages, RevTeX. Updated versio
Three Generation Neutrino Oscillation Parameters after SNO
We examine the solar neutrino problem in the context of the realistic three
neutrino mixing scenario including the SNO charged current (CC) rate. The two
independent mass squared differences and are taken to be in the solar and atmospheric ranges
respectively. We incorporate the constraints on m as obtained
by the SuperKamiokande atmospheric neutrino data and determine the allowed
values of , and from a combined
analysis of solar and CHOOZ data. Our aim is to probe the changes in the values
of the mass and mixing parameters with the inclusion of the SNO data as well as
the changes in the two-generation parameter region obtained from the solar
neutrino analysis with the inclusion of the third generation. We find that the
inclusion of the SNO CC rate in the combined solar + CHOOZ analysis puts a more
restrictive bound on . Since the allowed values of
are constrained to very small values by the CHOOZ experiment there is no
qualitative change over the two generation allowed regions in the plane. The best-fit comes in the LMA region and
no allowed area is obtained in the SMA region at 3 level from combined
solar and CHOOZ analysis.Comment: One reference added. Version to apprear in PR
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