827 research outputs found
Shadows of Relic Neutrino Masses and Spectra on Highest Energy GZK Cosmic Rays
The Ultra High Energy (UHE) neutrino scattering onto relic cosmic neutrinos
in galactic and local halos offers an unique way to overcome GZK cut-off. The
UHE nu secondary of UHE photo-pion decays may escape the GZK cut-off and travel
on cosmic distances hitting local light relic neutrinos clustered in dark
halos. The Z resonant production and the competitive W^+W^-, ZZ pair production
define a characteristic imprint on hadronic consequent UHECR spectra. This
imprint keeps memory both of the primary UHE nu spectra as well as of the
possible relic neutrino masses values, energy spectra and relic densities. Such
an hadronic showering imprint should reflect into spectra morphology of cosmic
rays near and above GZK 10^{19}-10^{21}eV cut-off energies. A possible neutrino
degenerate masses at eVs or a more complex and significant neutrino mass split
below or near Super-Kamiokande \triangle m_{\nu_{SK}}= 0.1 eV masses might be
reflected after each corresponding Z peak showering, into new twin unexpected
UHECR flux modulation behind GZK energies: E_{p} sim 3(frac{triangle
m_{\nu_{SK}}}/m_{\nu}10^{21}),eV.
Other shadowsof lightest, nearly massless, neutrinos m_{nu_{2K} simeq 0.001eV
simeq kT_{\nu}, their lowest relic temperatures, energies and densities might
be also reflected at even higher energies edges near Grand Unification: E_{p}
\sim 2.2(m_{\nu_{2K}/E_{\nu}})10^{23}, eV .Comment: 14 pages, 6 Figures,Invited Talk Heidelberg DARK 200
Nonlinear interplay of Alfven instabilities and energetic particles in tokamaks
The confinement of energetic particles (EP) is crucial for an efficient
heating of tokamak plasmas. Plasma instabilities such as Alfven Eigenmodes (AE)
can redistribute the EP population making the plasma heating less effective,
and leading to additional loads on the walls. The nonlinear dynamics of
toroidicity induced AE (TAE) is investigated by means of the global gyrokinetic
particle-in-cell code ORB5, within the NEMORB project. The nonperturbative
nonlinear interplay of TAEs and EP due to the wave-particle nonlinearity is
studied. In particular, we focus on the nonlinear modification of the
frequency, growth rate and radial structure of the TAE, depending on the
evolution of the EP distribution in phase space. For the ITPA benchmark case,
we find that the frequency increases when the growth rate decreases, and the
mode shrinks radially. This nonlinear evolution is found to be correctly
reproduced by means of a quasilinear model, namely a model where the linear
effects of the nonlinearly modified EP distribution function are retained.Comment: Submitted to Plasma Phys. Control. Fusio
An extended hybrid magnetohydrodynamics gyrokinetic model for numerical simulation of shear Alfv\'en waves in burning plasmas
Adopting the theoretical framework for the generalized fishbonelike
dispersion relation, an extended hybrid magnetohydrodynamics gyrokinetic
simulation model has been derived analytically by taking into account both
thermal ion compressibility and diamagnetic effects in addition to energetic
particle kinetic behaviors. The extended model has been used for implementing
an eXtended version of Hybrid Magnetohydrodynamics Gyrokinetic Code (XHMGC) to
study thermal ion kinetic effects on Alfv\'enic modes driven by energetic
particles, such as kinetic beta induced Alfv\'en eigenmodes in tokamak fusion
plasmas
Elliptic CMB Sky
The ellipticity of the anisotropy spots of the Cosmic Microwave Background
measured by the Wilkinson Microwave Anisotropy Probe (WMAP) has been studied.
We find an average ellipticity of about 2, confirming with a far larger
statistics similar results found first for the COBE-DMR CMB maps, and then for
the BOOMERanG CMB maps. There are no preferred directions for the obliquity of
the anisotropy spots. The average ellipticity is independent of temperature
threshold and is present on scales both smaller and larger than the horizon at
the last scattering. The measured ellipticity characteristics are consistent
with being the effect of geodesics mixing occurring in an hyperbolic Universe,
and can mark the emergence of CMB ellipticity as a new observable constant
describing the Universe. There is no way of simulating this effect. Therefore
we cannot exclude that the observed behavior of the measured ellipticity can
result from a trivial topology in the popular flat -CDM model, or from
a non-trivial topology.Comment: 10 pages, 5 figures, the version to appear in Mod.Phys.Lett.
Temperature Increase Dependence on Ultrasound Attenuation Coefficient in Innovative Tissue-mimicking Materials
Although high intensity focused ultrasound beams (HIFU) have found rapid agreement in clinical environment as a tool for non
invasive surgical ablation and controlled destruction of cancer cells, some aspects related to the interaction of ultrasonic waves
with tissues, such as the conversion of acoustic energy into heat, are not thoroughly understood. In this work, innovative tissue-
mimicking materials (TMMs), based on Agar and zinc acetate, have been used to conduct investigations in order to determine a
relation between the sample attenuation coefficient and its temperature increase measured in the focus region when exposed to an
HIFU beam. An empirical relation has been deduced establishing useful basis for further processes of validations of numerical
models to be adopted for customizing therapeutic treatments
Prognostic significance of organ dysfunction in cats with polytrauma
Polytrauma is a common emergency condition in small animals and is frequently associated with higher morbidity and mortality rates compared to minor trauma. Multiple Organ Dysfunction Syndrome (MODS) is a major complication of extensive traumatic injury, carrying a high risk of death despite intensive care treatment. Little is known about the prevalence and the prognostic impact of MODS in feline polytrauma. The current study aimed to prospectively evaluate the occurrence and the prognostic significance of organ dysfunction at admission in a population of polytraumatized cats. Cats with polytrauma requiring intensive care unit hospitalization were included and categorized according to outcome (survivors/non-survivors). Clinical and clinicopathological data, including scores of disease severity [Animal Trauma Triage Score (ATTS), APPLEfast, and APPLEfull], selected organ dysfunction and presence of MODS were evaluated upon admission, and analyzed with respect to mortality. Non-parametric statistics was performed and P < 0.05 was considered significant. Thirty-eight cats met the inclusion criteria: 8/38 (21%) had penetrating trauma, while 30/38 (79%) had blunt trauma. The overall in-hospital mortality was 37% (14/38). Cats with evidence of MODS upon admission had significantly higher frequency of death compared to cats without MODS (9/14 vs. 2/24 P = 0.0004). Hemostatic dysfunction, respiratory dysfunction, and MODS upon admission were significantly associated with mortality in the univariate logistic regression analysis (P = 0.005, P = 0.001, P = 0.001, respectively). The values of APPLEfast, APPLEfull, and ATTS were independently associated with a higher risk of death and positively correlated with the number of dysfunctional organs (P = 0.025, P = 0.004, P = 0.003, r = 0.57, P = 0.0002; r = 0.59, P = 0.0001; r = 0.55, P = 0.0003, respectively). Multiple Organ Dysfunction Syndrome is a common complication of feline polytrauma and its development is associated with increased disease severity and worse outcomes. The presence of hemostatic dysfunction and respiratory dysfunction upon admission is associated with a higher risk of death. The ATTS and the APPLE scores are useful prognostic tools for the assessment of cats with polytrauma
Nonlinear dynamics of beta induced Alfv\'en eigenmode driven by energetic particles
Nonlinear saturation of beta induced Alfv\'en eigenmode, driven by slowing
down energetic particles via transit resonance, is investigated by the
nonlinear hybrid magnetohyrodynamic gyro-kinetic code (XHMGC). Saturation is
characterized by frequency chirping and symmetry breaking between co- and
counter-passing particles, which can be understood as the the evidence of
resonance-detuning. The scaling of the saturation amplitude with the growth
rate is also demonstrated to be consistent with radial resonance detuning due
to the radial non-uniformity and mode structure
Stage 1-biomarkers of kidney injury in dogs undergoing constant rate infusion of hydroxyethyl starch 130/0.4
In veterinary medicine, investigations relating the effects of hydroxyethyl starch (HES) on renal function report contrasting results. This study aimed to assess the changes in the selected biomarkers of kidney injury in dogs after the administration of HES 130/0.4 as a constant rate infusion (CRI) for 24 h. Ten adult client-owned dogs with hypoalbuminemia (albumin < 2 g/dL) and ongoing fluid losses were included. Enrolled dogs received intravenous fluid therapy with crystalloids and a CRI of HES 130/0.4 at a dose of 2 mL/kg/h for 24 h. Serum creatinine (sCr), fractional excretion (FE) of electrolytes, urinary protein to creatinine ratio (UPC), urinary albumin to creatinine ratio (UAC), SDS-page, and urinary neutrophil gelatinase-associated lipocalin (uNGAL) were measured at the baseline before HES infusion, and after 24 h (T24) and 48 h (T48) from the baseline. No statistically significant difference was found between the baseline value vs. T24 and the baseline vs. T48 for sCr, UAC, UPC, FE of sodium, chloride and calcium, and uNGAL. A significant increase in FEK (p = 0.04) was noticed between the baseline and T48. In this study sample of hypoalbuminemic dogs, HES 130/0.4 at the dose and rate of infusion applied did not cause any significant changes in the investigated biomarkers of kidney injury
High Order Correction Terms for The Peak-Peak Correlation Function in Nearly-Gaussian Models
One possible way to investigate the nature of the primordial power spectrum
fluctuations is by investigating the statistical properties of the local
maximum in the density fluctuation fields. In this work we present a study of
the mean correlation function, , and the correlation function for high
amplitude fluctuations (the peak-peak correlation) in a slighlty non-Gaussian
context. From the definition of the correlation excess, we compute the Gaussian
two-point correlation function and, using an expansion in Generalized Hermite
polynomials, we estimate the correlation of high density peaks in a
non-Gaussian field with generic distribution and power spectrum. We also apply
the results obtained to a scale-mixed distribution model, which correspond to a
nearly Gaussian model. The results reveal that, even for a small deviation from
Gaussianity, we can expect high density peaks to be much more correlated than
in a Gaussian field with the same power spectrum. In addition, the calculations
reveal how the amplitude of the peaks in the fluctuations field is related to
the existing correlations. Our results may be used as an additional tool to
investigate the behavior of the N-point correlation function, to understand how
non-Gaussian correlations affect the peak-peak statistics and extract more
information about the statistics of the density field.Comment: Accepted for publication in A&
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