75 research outputs found
Tomografia sísmica da litosfera continental algarvia
RESUMO: O presente estudo de Tomografia é focado na região do Algarve. Para a localização dos eventos e determinação do modelo de velocidades, são utilizadas as ondas P e S. Os dados foram obtidos entre Janeiro/2006 e Julho/2007. As estimativa dos tempos de origem e coordenadas hipocentrais foram calculadas. A relocalização de eventos e inversão linear respeitaram dois passos: 1) determinação do modelo mínimo 1-D e 2) relocalização dos hipocentros e obtenção da estrutura 3-D em termos de velocidades das ondas P.
ABSTRACT: The present Tomographic study is focused on Algarve region. For event location and velocity model determination P and S waves were used. Data was collected between January/2006 and July/2007. The estimation of origin times and hipocentral determination were calculated. Relocation of events and linear inversion respected two steps: 1) minimum velocity model determination and 2) hipocentral relocation and 3-D Earth structure determination in terms of P wave velocities
Benchmark Parameters for CMB Polarization Experiments
The recently detected polarization of the cosmic microwave background (CMB)
holds the potential for revealing the physics of inflation and gravitationally
mapping the large-scale structure of the universe, if so called B-mode signals
below 10^{-7}, or tenths of a uK, can be reliably detected. We provide a
language for describing systematic effects which distort the observed CMB
temperature and polarization fields and so contaminate the B-modes. We identify
7 types of effects, described by 11 distortion fields, and show their
association with known instrumental systematics such as common mode and
differential gain fluctuations, line cross-coupling, pointing errors, and
differential polarized beam effects. Because of aliasing from the small-scale
structure in the CMB, even uncorrelated fluctuations in these effects can
affect the large-scale B modes relevant to gravitational waves. Many of these
problems are greatly reduced by having an instrumental beam that resolves the
primary anisotropies (FWHM << 10'). To reach the ultimate goal of an
inflationary energy scale of 3 \times 10^{15} GeV, polarization distortion
fluctuations must be controlled at the 10^{-2}-10^{-3} level and temperature
leakage to the 10^{-4}-10^{-3} level depending on effect. For example pointing
errors must be controlled to 1.5'' rms for arcminute scale beams or a percent
of the Gaussian beam width for larger beams; low spatial frequency differential
gain fluctuations or line cross-coupling must be eliminated at the level of
10^{-4} rms.Comment: 11 pages, 5 figures, submitted to PR
Deep Submarine Giant Scours in northern Gulf of Cadiz (offshore SW Iberia): a singular case of sedimentary and tectonic coupling?
Multi-beam swath bathymetry carried out in NW Gulf of Cadiz(offshore SW Iberia - MATESPRO campaign) revealed several intriguing morphologic features, lying at depths between -3900 and - 4700 m., in an area characterized by very shallow general slope gradients (dipping approximately 0.4 degrees). These three dimensional features are characterized by elliptical crescent shapes of kilometric length (major axis around 5 km), displaying internal escarpments up to 100 m high and slopes varying between 6 and 14 degrees.A single channel seismic profile acquired across two of these features shows that they have a sub-surface composite structure. The internal part of the crescent consists of a depression filled up with upslope prograding sedimentary units developing towards the scarp that sharply truncates the sedimentary horizons. The growth processes of these structures appears to be by retrogressive displacement of a morphological scarp and remobilization followed by deposition of the eroded material in front of the scarp, prograding towards it. This process is similar to the development of contourite bodies in which the current direction is parallel to the scarp, whilst in the present case the flow direction may be mainly perpendicular to the scarp.These units are overlain by a sub-horizontal turbidite-like sedimentary unit that partially infills the depression. A deep multi-channel seismic profile across the same structure revealed the existence of an underlying thrust, part of a major structure, the Gulf of Cadiz Accretionary Prism. These singular features are interpreted as the coupled of sedimentary and tectonic processes. It is proposed that the Deep Submarine Giant Scours formed when a local morphologic irregularity, corresponding to the bathymetric expression of movement on an underlying thrust, is enhanced by the erosional activity of turbidity and thermohaline bottom currents driven by the formation of local eddies in front of the scarp. The drift results from the re-deposition of the eroded material in the same location
Endocannabinoids and cardiovascular prevention: real progress?
The prevalence of obesity continues to increase and represents one of the principal causes of cardiovascular morbidity and mortality. After the discovery of a specific receptor of the psychoactive principle of marijuana, the cannabinoid receptors and their endogenous ligands, several studies have demonstrated the role of this system in the control of food intake and energy balance and its overactivity in obesity. Recent studies with the CB1 receptor antagonist rimonabant have demonstrated favorable effects such as a reduction in body weight and waist circumference and an improvement in metabolic factors (cholesterol, triglycerides, glycemia etc). Therefore, the antagonism of the endocannabinoid (EC) system, if recent data can be confirmed, could be a new treatment target for high risk overweight or obese patients. Obesity is a growing problem that has epidemic proportions worldwide and is associated with an increased risk of premature death (1–3). Individuals with a central deposition of fats have elevated cardiovascular morbidity and mortality (including stroke, heart failure and myocardial infarction) and, because of a growing prevalence not only in adults but also in adolescents, it was reclassified in AHA guidelines as a “major modifiable risk factor” for coronary heart disease (4, 5). Although first choice therapy in obesity is based on correcting lifestyle (diet and physical activity) in patients with abdominal obesity and high cardiovascular risk and diabetes, often it is necessary to use drugs which reduce the risks. The EC system represents a new target for weight control and the improvement of lipid and glycemic metabolism (6, 7)
Is cosmology consistent?
We perform a detailed analysis of the latest CMB measurements (including
BOOMERaNG, DASI, Maxima and CBI), both alone and jointly with other
cosmological data sets involving, e.g., galaxy clustering and the Lyman Alpha
Forest. We first address the question of whether the CMB data are internally
consistent once calibration and beam uncertainties are taken into account,
performing a series of statistical tests. With a few minor caveats, our answer
is yes, and we compress all data into a single set of 24 bandpowers with
associated covariance matrix and window functions. We then compute joint
constraints on the 11 parameters of the ``standard'' adiabatic inflationary
cosmological model. Out best fit model passes a series of physical consistency
checks and agrees with essentially all currently available cosmological data.
In addition to sharp constraints on the cosmic matter budget in good agreement
with those of the BOOMERaNG, DASI and Maxima teams, we obtain a heaviest
neutrino mass range 0.04-4.2 eV and the sharpest constraints to date on gravity
waves which (together with preference for a slight red-tilt) favors
``small-field'' inflation models.Comment: Replaced to match accepted PRD version. 14 pages, 12 figs. Tiny
changes due to smaller DASI & Maxima calibration errors. Expanded neutrino
and tensor discussion, added refs, typos fixed. Combined CMB data, window and
covariance matrix at http://www.hep.upenn.edu/~max/consistent.html or from
[email protected]
Safety and Health at Work - Assessment tool: Dairy Products
This manual aims to assist the Work Health and Safety Assessment Tool – Dairy Products user, in carrying out a simplified and easy-to-use occupational risk assessment with a view to adopting risk control solutions at workplaces.
The design of this tool trie to provide an instrument capable of being used without internet access or specific software installation.
In addition to its main purpose, this tool can also be used for workers consultation or training actions, provided as a complement of the other instruments developed within the scope of this project.
The tool is organized in three distinct parts (see Figure 1): the first, where a checklist is filled out, from which a graphical overview is obtained, which will give the overview of the level of risk control (second part). This synthesis of results allows the user to immediately visualize the level of control of the main risks and in which will have to make major interventions. Finally, the third part appears, where a report is generated with solutions, particularized for each one of the risks in which the adoption of measures proves necessary.info:eu-repo/semantics/publishedVersio
Safety and Health at Work: Assessment tool- Bakery/Pastry Products
This manual aims to assist the Work Health and Safety Assessment Tool – Bread/Pastry Products user, in carrying out a simplified and easy-to-use occupational risk assessment with a view to adopting risk control solutions at workplaces.
The design of this tool trie to provide an instrument capable of being used without internet access or specific software installation.
In addition to its main purpose, this tool can also be used for workers consultation or training actions, provided as a complement of the other instruments developed within the scope of this project.
The tool is organized in three distinct parts (see Figure 1): the first, where a checklist is filled out, from which a graphical overview is obtained, which will give the overview of the level of risk control (second part). This synthesis of results allows the user to immediately visualize the level of control of the main risks and in which will have to make major interventions. Finally, the third part appears, where a report is generated with solutions, particularized for each one of the risks in which the adoption of measures proves necessary.info:eu-repo/semantics/publishedVersio
The significance of the largest scale CMB fluctuations in WMAP
We investigate anomalies reported in the Cosmic Microwave Background maps
from the Wilkinson Microwave Anisotropy Probe (WMAP) satellite on very large
angular scales and discuss possible interpretations. Three independent
anomalies involve the quadrupole and octopole:
1. The cosmic quadrupole on its own is anomalous at the 1-in-20 level by
being low (the cut-sky quadrupole measured by the WMAP team is more strikingly
low, apparently due to a coincidence in the orientation of our Galaxy of no
cosmological significance);
2. The cosmic octopole on its own is anomalous at the 1-in-20 level by being
very planar;
3. The alignment between the quadrupole and octopole is anomalous at the
1-in-60 level.
Although the a priori chance of all three occurring is 1 in 24000, the
multitude of alternative anomalies one could have looked for dilutes the
significance of such a posteriori statistics. The simplest small universe model
where the universe has toroidal topology with one small dimension of order half
the horizon scale, in the direction towards Virgo, could explain the three
items above. However, we rule this model out using two topological tests: the
S-statistic and the matched circle test.Comment: N.B. that our results do not rule out the recently proposed
dodecahedron model of Luminet, Weeks, Riazuelo, Lehoucq & Uzan, which has a
36 degree twist between matched circles. 12 pages, 5 figs; more info at
http://www.hep.upenn.edu/~angelica/topology.htm
Predicting the distribution of a threatened albatross: The importance of competition, fisheries and annual variability
CP Asymmetries in B_s Decays and Spontaneous CP violation
We study possible effects of new physics in CP asymmetries in two-body
decays in left-right models with spontaneous CP violation. Considering the
contributions of new CP phases to the mixing as well as to the penguin
dominated decay amplitudes we show that, with the present constraints, large
deviations from the standard model predictions in CP asymmetries are allowed in
both cases. Detection of the new physics can be done by measuring non-zero
asymmetries which are predicted to vanish in the standard model or by comparing
two measurements which are predicted to be equal in the standard model. In
particular, we show that the measurement of the CKM angle in
electroweak penguin dominated processes
can largely be affected by the new physics.Comment: References and discussion added, version to be published in PR
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