Daily morphological changes determined by high-energy events on an embayed beach: a qualitative model

This paper examines the daily morphological responses of Sununga Beach, an embayed beach located on the south-eastern Brazilian coast, to storms in the South Atlantic Ocean. The main mechanisms and timing of beach erosion and accretion, the relationship between wave height and direction, and beach volume changes are considered, to establish a qualitative model for short-term embayed beach morphological changes. The methodology consisted of daily topographic surveys during the month of May in 2001, 2002, and 2003, using an RTK-GPS (real-time kinematics global positioning system). Weather and wave model results were used to correlate hydrodynamics and beach morphology. The results indicate that the morphodynamics of Sununga Beach are characterized by a process of beach rotation, which occurred more or less clearly during all three surveys. Unlike what has been commonly described in the literature for longer time intervals and alternations of fair and stormy weather, the beach rotation processes on Sununga Beach occurred under conditions of moderate-to-high wave energy change (wave heights greater than 2 m). An integrated evaluation of the behaviour of the meteorological aspects, together with beach morphology, enabled us to recognize that extra-tropical cyclones were the most important agent in remobilizing the beach planform, whether in beach rotation or in cross-shore erosion. Copyright (C) 2010 John Wiley & Sons, Ltd.

A search for anisotropy in the arrival directions of ultra high energy cosmic rays recorded at the Pierre Auger Observatory

Observations of cosmic rays arrival directions made with the Pierre Auger Observatory have previously provided evidence of anisotropy at the 99% CL using the correlation of ultra high energy cosmic rays (UHECRs) with objects drawn from the Veron-Cetty Veron catalog. In this paper we report on the use of three catalog independent methods to search for anisotropy. The 2pt-L, 2pt+ and 3pt methods, each giving a different measure of self-clustering in arrival directions, were tested on mock cosmic ray data sets to study the impacts of sample size and magnetic smearing on their results, accounting for both angular and energy resolutions. If the sources of UHECRs follow the same large scale structure as ordinary galaxies in the local Universe and if UHECRs are deflected no more than a few degrees, a study of mock maps suggests that these three method can efficiently respond to the resulting anisotropy with a P-value = 1.0% or smaller with data sets as few as 100 events. using data taken from January 1, 2004 to July 31, 2010 we examined the 20, 30, ... , 110 highest energy events with a corresponding minimum energy threshold of about 49.3 EeV. The minimum P-values found were 13.5% using the 2pt-L method, 1.0% using the 2pt+ method and 1.1% using the 3pt method for the highest 100 energy events. In view of the multiple (correlated) scans performed on the data set, these catalog-independent methods do not yield strong evidence of anisotropy in the highest energy cosmic rays.

Latent track radius of PTFE irradiated with high energy ion beam

PTFE foils were irradiated with different ion beams (Xe, Au and U) with energies up to 1.5 GeV and fluences between 1 x 10(8) and 1 x 10(13) ions/cm(2) at room temperature. The induced modifications in the polymer were analyzed by FTIR, UV-Vis spectroscopy, and XRD. In the FTIR spectra, the CF2 degradation accompanied by the formation of CF3 terminal and side groups were observed. In the UV-Vis spectra, the observed increase in the absorption at UV wavelengths is an indication of polymer carbonization. From XRD, the amorphization of the material was evidenced by the decrease in the intensity of the main diffraction peak. An exponential fit of the intensity of the IR absorption peaks resulted in the following values: 2.9 +/- 0.8; 4.5 +/- 0.9 and 5.6 +/- 0.8 nm for the latent track radius after irradiation with Xe, Au and U beams, respectively. (C) 2011 Elsevier B.V. All rights reserved.

Performance of electronic devices submitted to X-rays and high energy proton beams

In this work we have studied the radiation effects on MOSFET electronic devices. The integrated circuits were exposed to 10 key X-ray radiation and 2.6 MeV energy proton beam. We have irradiated MOSFET devices with two different geometries: rectangular-gate transistor and circular-gate transistor. We have observed the cumulative dose provokes shifts on the threshold voltage and increases or decreases the transistor's off-state and leakage current. The position of the trapped charges in modern CMOS technology devices depends on radiation type, dose rate, total dose, applied bias and is a function of device geometry. We concluded the circular-gate transistor is more tolerant to radiation than the rectangular-gate transistor. (C) 2011 Elsevier B.V. All rights reserved.

The spectrum of high-energy cosmic rays measured with KASCADE-Grande

The energy spectrum of cosmic rays between 10(16) eV and 10(18) eV, derived from measurements of the shower size (total number of charged particles) and the total muon number of extensive air showers by the KASCADE-Grande experiment, is described. The resulting all-particle energy spectrum exhibits strong hints for a hardening of the spectrum at approximately 2 . 10(16) eV and a significant steepening at approximate to 8 . 10(16) eV. These observations challenge the view that the spectrum is a single power law between knee and ankle. Possible scenarios generating such features are discussed in terms of astrophysical processes that may explain the transition region from galactic to extragalactic origin of cosmic rays. (C) 2012 Elsevier B.V. All rights reserved.

Effects of high-energy astrophysical events on habitable planets

With the possible exception of meteor impacts, high-energy astrophysical events such as supernovae, gamma-ray bursts (GRB) and flares are usually not taken into account for biological and evolutionary studies due to their low rates of occurrence. We show that a class of these events may occur at distances and time scales in which their biological effects are non-negligible, maybe more frequent than the impacts of large asteroids. We review the effects of four transient astrophysical sources of ionizing radiation on biospheres - stellar flares, giant flares from soft gamma repeaters (SGR), supernovae and GRB. The main damaging features of them are briefly discussed and illustrated. We point out some open problems and ongoing work. Received 28 February 2012, accepted 6 July 2012, first published online 10 August 2012

SEARCH FOR POINT-LIKE SOURCES OF ULTRA-HIGH ENERGY NEUTRINOS AT THE PIERRE AUGER OBSERVATORY AND IMPROVED LIMIT ON THE DIFFUSE FLUX OF TAU NEUTRINOS

The surface detector array of the Pierre Auger Observatory can detect neutrinos with energy E-nu between 10(17) eV and 10(20) eV from point-like sources across the sky south of +55 degrees and north of -65 degrees declinations. A search has been performed for highly inclined extensive air showers produced by the interaction of neutrinos of all flavors in the atmosphere (downward-going neutrinos), and by the decay of tau leptons originating from tau neutrino interactions in Earth's crust (Earth-skimming neutrinos). No candidate neutrinos have been found in data up to 2010 May 31. This corresponds to an equivalent exposure of similar to 3.5 years of a full surface detector array for the Earth-skimming channel and similar to 2 years for the downward-going channel. An improved upper limit on the diffuse flux of tau neutrinos has been derived. Upper limits on the neutrino flux from point-like sources have been derived as a function of the source declination. Assuming a differential neutrino flux k(PS) . E-nu(-2). from a point-like source, 90% confidence level upper limits for k(PS) at the level of approximate to 5x10(-7) and 2.5x10(-6) GeV cm(-2) s(-1) have been obtained over a broad range of declinations from the searches for Earth-skimming and downward-going neutrinos, respectively.

On Ti-18Si-6B and Ti-7.5Si-22.5B powder alloys prepared by high-energy ball milling and sintering

Recently, a new ternary phase was discovered in the Ti-Si-B system, located near the Ti6Si2B composition. The present study concerns the preparation of titanium alloys that contain such phase mixed with α-titanium and other intermetallic phases. High-purity powders were initially processed in a planetary ball-mill under argon atmosphere with Ti-18Si-6B and Ti-7.5Si-22.5B at. (%) initial compositions. Variation of parameters such as rotary speed, time, and ball diameters were adopted. The as-milled powders were pressureless sintered and hot pressed. Both the as-milled and sintered materials were characterized by X-ray diffraction, scanning electron microscopy and energy-dispersive spectrometry. Sintered samples have presented equilibrium structures formed mainly by the α-Ti+Ti6Si2B+Ti5Si3+TiB phases. Silicon and boron peaks disappear throughout the milling processes, as observed in the powder diffraction data. Furthermore, an iron contamination of up to 10 at. (%) is measured by X-ray spectroscopy analysis on some regions of the sintered samples. Density, hardness and tribological results for these two compositions are also presented here.

Bounds on the density of sources of ultra-high energy cosmic rays from the Pierre Auger Observatory

We derive lower bounds on the density of sources of ultra-high energy cosmic rays from the lack of significant clustering in the arrival directions of the highest energy events detected at the Pierre Auger Observatory. The density of uniformly distributed sources of equal intrinsic intensity was found to be larger than ~(0.06 - 5) × '10 POT. -4' 'Mpc POT. -3' at 95% CL, depending on the magnitude of the magnetic deflections. Similar bounds, in the range (0.2 - 7) × '10 POT. -4' 'Mpc POT. -3', were obtained for sources following the local matter distribution.

Total energy value and percentage contribuition of calories from macronutrients in the diet of elderly individuals from Fortaleza, state of Ceara, Brazil

Objective: Describe the total energy value and percentage contribution of calories from macronutrients in the diet of elderly individuals living in Fortaleza/CE. Methods: This is a population-based, cross-sectional domiciliary study, which included 458 elderly individuals (66.6% women). The variables evaluated were total energy value (TEV) and the percentage contribution of calories from proteins, carbohydrates, and lipids. The results are shown as mean, standard deviation, and percentile distribution (P5, P10, P25, P50, P75, P90, P95). The Student's t-test and analysis of variance (one-way ANOVA) with LSD post-hoc tests were used to determine the statistical significance of means between two groups and among three or more groups, respectively. Results: When comparing the mean values of TEV among categories of socioeconomic and demographic variables, statistically significant differences were found between women for ethnicity, years of schooling and socioeconomic level. Among men, differences were found for years of schooling and socioeconomic level. The mean energy value of men's diet was significantly higher than that of women (1475.8 kcal and 1236.4 kcal, respectively). The mean values of calorie percentage contribution from proteins, carbohydrates, and lipids were similar between men and women. Conclusion: The elderly of this study showed significant differences in mean values of TEV between sexes and between the categories years of schooling and socioeconomic level. Women also showed significant differences between the ethnic categories. The mean relative contribution of macronutrients in TEV was similar between genders and age groups.

High-fat diet causes an imbalance in the colonic serotonergic system promoting adipose tissue enlargement and dysplasia in rats

A high-fat (HF) diet, the serotonergic system and stromal elements have all been implicated in colon carcinogenesis. We investigated whether the colonic serotonergic system could play a main role in the development of colonic dysplasia and stromal reactivity in carcinogen-treated rats under HF diet. For this, dimethylhydrazine-treated rats were fed with standard diet and a HF diet. Fat distribution was quantified by computerized tomography exam, serotonergic activity was analyzed by high-performance liquid chromatography, gene expression, and immunohistochemistry, which along with histopathological technique enabled us to enumerate dysplasia, microvessels density, cell proliferation and COX-2 expression. We found that the HF diet induced an increase in the amount of viscera! adipose tissue, even without expressive changes in the average body weight. This was correlated with a loss of serotonergic balance in colon tissue. Moreover, the HF diet promoted dysplasia and microvessel density in association with increased proliferation and COX-2 expression within pericryptal colonic stroma. Our current findings suggest that a HF diet promotes the enlargement of adipose tissue via loss of control in colon serotonergic activity, which enhances colonic dysplasia by supporting microvessel development. (C) 2012 Elsevier Ireland Ltd. All rights reserved.

A Low-Protein, High-Carbohydrate Diet Increases Fatty Acid Uptake and Reduces Norepinephrine-Induced Lipolysis in Rat Retroperitoneal White Adipose Tissue

A low-protein, high-carbohydrate (LPHC) diet for 15 days increased the lipid content in the carcass and adipose tissues of rats. The aim of this work was to investigate the mechanisms of this lipid increase in the retroperitoneal white adipose tissue (RWAT) of these animals. The LPHC diet induced an approximately two- and tenfold increase in serum corticosterone and TNF-alpha, respectively. The rate of de novo fatty acid (FA) synthesis in vivo was reduced (50%) in LPHC rats, and the lipoprotein lipase activity increased (100%). In addition, glycerokinase activity increased (60%), and the phosphoenolpyruvate carboxykinase content decreased (27%). Basal [U-C-14]-glucose incorporation into glycerol-triacylglycerol did not differ between the groups; however, in the presence of insulin, [U-C-14]-glucose incorporation increased by 124% in adipocytes from only control rats. The reductions in IRS1 and AKT content as well as AKT phosphorylation in the RWAT from LPHC rats and the absence of an insulin response suggest that these adipocytes have reduced insulin sensitivity. The increase in NE turnover by 45% and the lack of a lipolytic response to NE in adipocytes from LPHC rats imply catecholamine resistance. The data reveal that the increase in fat storage in the RWAT of LPHC rats results from an increase in FA uptake from circulating lipoproteins and glycerol phosphorylation, which is accompanied by an impaired lipolysis that is activated by NE.

System size and energy dependence of near-side dihadron correlations

Two-particle azimuthal (Delta phi) and pseudorapidity (Delta eta) correlations using a trigger particle with large transverse momentum (p(T)) in d+Au, Cu+Cu, and Au+Au collisions at root s(NN) = 62.4 GeV and 200 GeV from the STAR experiment at the Relativistic Heavy Ion Collider are presented. The near-side correlation is separated into a jet-like component, narrow in both Delta phi and Delta eta, and the ridge, narrow in Delta phi but broad in Delta eta. Both components are studied as a function of collision centrality, and the jet-like correlation is studied as a function of the trigger and associated p(T). The behavior of the jet-like component is remarkably consistent for different collision systems, suggesting it is produced by fragmentation. The width of the jet-like correlation is found to increase with the system size. The ridge, previously observed in Au+Au collisions at root s(NN) = 200 GeV, is also found in Cu+Cu collisions and in collisions at root s(NN) = 62.4 GeV, but is found to be substantially smaller at root s(NN) = 62.4 GeV than at root s(NN) = 200 GeV for the same average number of participants (< N-part >). Measurements of the ridge are compared to models.

Optical transition radiation used in the diagnostic of low energy and low current electron beams in particle accelerators

Optical transition radiation (OTR) plays an important role in beam diagnostics for high energy particle accelerators. Its linear intensity with beam current is a great advantage as compared to fluorescent screens, which are subject to saturation. Moreover, the measurement of the angular distribution of the emitted radiation enables the determination of many beam parameters in a single observation point. However, few works deals with the application of OTR to monitor low energy beams. In this work we describe the design of an OTR based beam monitor used to measure the transverse beam charge distribution of the 1.9-MeV electron beam of the linac injector of the IFUSP microtron using a standard vision machine camera. The average beam current in pulsed operation mode is of the order of tens of nano-Amps. Low energy and low beam current make OTR observation difficult. To improve sensitivity, the beam incidence angle on the target was chosen to maximize the photon flux in the camera field-of-view. Measurements that assess OTR observation (linearity with beam current, polarization, and spectrum shape) are presented, as well as a typical 1.9-MeV electron beam charge distribution obtained from OTR. Some aspects of emittance measurement using this device are also discussed. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4748519]

A rationale for long-lived quarks and leptons at the LHC: low energy flavour theory

In the framework of gauged flavour symmetries, new fermions in parity symmetric representations of the standard model are generically needed for the compensation of mixed anomalies. The key point is that their masses are also protected by flavour symmetries and some of them are expected to lie way below the flavour symmetry breaking scale(s), which has to occur many orders of magnitude above the electroweak scale to be compatible with the available data from flavour changing neutral currents and CP violation experiments. We argue that, actually, some of these fermions would plausibly get masses within the LHC range. If they are taken to be heavy quarks and leptons, in (bi)-fundamental representations of the standard model symmetries, their mixings with the light ones are strongly constrained to be very small by electroweak precision data. The alternative chosen here is to exactly forbid such mixings by breaking of flavour symmetries into an exact discrete symmetry, the so-called proton-hexality, primarily suggested to avoid proton decay. As a consequence of the large value needed for the flavour breaking scale, those heavy particles are long-lived and rather appropriate for the current and future searches at the LHC for quasi-stable hadrons and leptons. In fact, the LHC experiments have already started to look for them.