842 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
CMB Polarization Systematics, Cosmological Birefringence and the Gravitational Waves Background
Cosmic Microwave Background experiments must achieve very accurate
calibration of their polarization reference frame to avoid biasing the
cosmological parameters. In particular, a wrong or inaccurate calibration might
mimic the presence of a gravitational wave background, or a signal from
cosmological birefringence, a phenomenon characteristic of several
non-standard, symmetry breaking theories of electrodynamics that allow for
\textit{in vacuo} rotation if the polarization direction of the photon.
Noteworthly, several authors have claimed that the BOOMERanG 2003 (B2K)
published polarized power spectra of the CMB may hint at cosmological
birefringence. Such analyses, however, do not take into account the reported
calibration uncertainties of the BOOMERanG focal plane. We develop a formalism
to include this effect and apply it to the BOOMERanG dataset, finding a
cosmological rotation angle . We also
investigate the expected performances of future space borne experiment, finding
that an overall miscalibration larger then for Planck and
for EPIC, if not properly taken into account, will produce a bias on the
constraints on the cosmological parameters and could misleadingly suggest the
presence of a GW background.Comment: 10 pages, 3 figure
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.
Living in a fringe environment: three Late Roman settlements in the Kharga Oasis (Egypt's Western Desert)
This article presents a comparative analysis of three Late Roman sites located at the northern outskirts of the Kharga Oasis in Egypt's Western Desert: Umm al-Dabadib, Ayn al-Labakha, and the Gib/Sumayra Complex. These were part of the district of the Oasis Magna, which included the oases of Dakhla and Kharga. An analysis of their layout, including both shape and extent, is followed by an evaluation of their absolute and relative positions. These data are then compared to the administrative and historical contexts within which the three sites flourished. Both administrative and economic aspects are considered, as well as the presence of the army. The complex picture that emerges suggests that these three sites played several roles at the same time and were part of a large-scale strategic design that encompassed not only the Kharga Oasis but the entire Western Desert
Ulipristal acetate before in vitro fertilization: Efficacy in infertile women with submucous fibroids
Background: The presence of submucous fibroids strongly impacts on IVF results, therefore, these patients should be considered for surgical or medical treatment. The aim of this study was to assess the role of Ulipristal acetate (UPA), a selective progesterone receptor modulator, in restoring uterine cavity deformation due to submucous fibroids, in infertile patients attempting an IVF treatment. The secondary study outcome was to evaluate the impact of preconception UPA treatment on rate of biochemical pregnancy, ongoing pregnancy, and live birth compared to a control group without fibroids. Methods: Infertile patients with submucosal fibroid (Type 1 and Type 2 according to FIGO classification) were enrolled in the study as fibroids group and received 1 to 3 treatment cycles of UPA, according to their response, as reflected by fibroid volume reduction and restoration of normal uterine cavity. Patients in control group were randomly selected from a general IVF cohort by a ratio of 2:1 with fibroids group, matched by age, BMI, type and cause of infertility and antral follicle count. The impact of UPA on fibroids volume reduction was evaluated. IVF outcome was compared between groups. Results: Twenty-six patients underwent UPA treatment revealed a mean volume reduction of their fibroids of 41%. A total of 15 (57.6%) biochemical pregnancy were obtained, resulting in 13 (50%) ongoing pregnancy and 9 (34.6%) healthy babies were already delivered. Similar results were obtained in control group. Conclusion: Restoration of normal uterine cavity by UPA treatment prior to IVF treatment avoids surgery and establishes a pregnancy rate comparable to a control group without fibroids
Hybrid Treatment of Acute Abdominal Aortic Thrombosis Presenting with Paraplegia
Acute thrombotic or embolic occlusion of the abdominal aorta is a rare vascular emergency associated with high morbidity and mortality rates. Classically, the clinical presentation is a severe peripheral ischemia with bilateral leg pain as the predominant feature. Aortic occlusion presenting as an isolated acute onset of paraplegia due to spinal cord ischemia is very rare and requires improved awareness to prevent adverse outcomes associated with delayed diagnosis. We report the case of a 54-year-old man who presented with sudden paraplegia due to the thrombotic occlusion of the infrarenal aorta involving the first segment of the common iliac arteries on both sides; emergent transperitoneal aorto iliac thrombectomy combined with the endovascular iliac kissing-stent technique were performed achieving perioperative complete regression of the symptoms
Improved constraints on primordial non-Gaussianity for the Wilkinson Microwave Anisotropy Probe 5-yr data
We present new constraints on the non-linear coupling parameter fnl with the
Wilkinson Microwave Anisotropy Probe (WMAP) data. We use an updated method
based on the spherical Mexican hat wavelet (SMHW) which provides improved
constraints on the fnl parameter. This paper is a continuation of a previous
work by Curto et al. where several third order statistics based on the SMHW
were considered. In this paper, we use all the possible third order statistics
computed from the wavelet coefficient maps evaluated at 12 angular scales. The
scales are logarithmically distributed from 6.9 arcmin to 500 arcmin. Our
analysis indicates that fnl is constrained to -18 < fnl < +80 at 95% confidence
level (CL) for the combined V+W WMAP map. This value has been corrected by the
presence of undetected point sources, which adds a positive contribution of
Delta_fnl = 6 +- 5. Our result excludes at ~99% CL the best-fitting value
fnl=87 reported by Yadav & Wandelt. We have also constrained fnl for the Q, V
and W frequency bands separately, finding compatibility with zero at 95 % CL
for the Q and V bands but not for the W band. We have performed some further
tests to understand the cause of this deviation which indicate that systematics
associated to the W radiometers could be responsible for this result. Finally
we have performed a Galactic North-South analysis for fnl. We have not found
any asymmetry, i.e. the best-fitting fnl for the northern pixels is compatible
with the best-fitting fnl for the southern pixels.Comment: 6 pages, 4 figures, 4 tables. Accepted for publication in Ap
- …