339 research outputs found
The Sunyaev-Zeldovich effect as a probe of the galaxy formation process
The Sunyaev-Zeldovich (SZ) effect has proven to be an extremely powerful tool
to study the physical and evolutionary properties of rich clusters of galaxies.
Upcoming SZ experiments, with their much improved sensitivity and angular
resolution, will provide unique information also on phases of galaxy evolution
characterized by the presence of large amounts of hot proto-galactic gas. We
present a preliminary analysis of the SZ signals that can be expected at the
collapse of the proto-galaxy when, according to the standard scenario, the gas
is heated at its virial temperature, and during episodes of strong energy
injections from the active nucleus. The contributions of such signals to excess
power on arc-minute scales recently found by CBI and BIMA experiments are
briefly discussed.Comment: 10 pages, 2 figures, to appera in proc. Int. Symp. "Plasmas in the
Laboratory and in the Universe: new insights and new challenges", Como, Sept.
200
Two ways to be endemic. Alps and Apennines are different functional refugia during climatic cycles
Endemics co-occur because they evolved in situ and persist regionally or because they evolved ex situ and later dispersed to shared habitats, generating evolutionary or ecological endemicity centres, respectively. We investigate whether different endemicity centres can intertwine in the region ranging from Alps to Sicily, by studying their butterfly fauna. We gathered an extensive occurrence data set for butterflies of the study area (27,123 records, 269 species, in cells of 0.5 × 0.5 degrees of latitude-longitude). We applied molecular-based delimitation methods (GMYC model) to 26,557 cytochrome c oxidase subunit 1 (COI) sequences of Western Palearctic butterflies. We identified entities based on molecular delimitations and/or the checklist of European butterflies and objectively attributed occurrences to their most probable entity. We obtained a zoogeographic regionalisation based on the 69 endemics of the area. Using phylogenetic ANOVA we tested if endemics from different centres differ from each other and from nonendemics for key ecological traits and divergence time. Endemicity showed high incidence in the Alps and Southern Italy. The regionalisation separated the Alps from the Italian Peninsula and Sicily. The endemics of different centres showed a high turnover and differed in phylogenetic distances, phenology and distribution traits. Endemics are on average younger than nonendemics and the Peninsula-Sicily endemics also have lower variance in divergence than those from the Alps. The observed variation identifies Alpine endemics as paleoendemics, now occupying an ecological centre, and the Peninsula-Sicily ones as neoendemics, that diverged in the region since the Pleistocene. The results challenge the common view of the Alpine-Apennine area as a single “Italian refugium”
A comparison of sacral neuromodulation vs. transvaginal electrical stimulation for the treatment of refractory overactive bladder: The impact on quality of life, body image, sexual function, and emotional well-being
Overactive bladder syndrome (OAB) is defined by the presence of urinary urgency, with or without urge incontinence, usually accompanied by an increase in urinary frequency and nocturia in the absence of urinary tract infections (UTI) or other diseases. The overall prevalence of OAB symptoms in the female population is reported to be 16.6% and increases with advancing age and menopause. The aetiology of OAB is not fully understood and is likely to affect a heterogeneous population of patients due to changes to their central and peripheral nervous systems. Although OAB is frequently associated with female sexual dysfunction (FSD), its real impact on sexual function in women has been evaluated only in a few studies. The first line of treatment for OAB includes behavioural modification and physical therapy, either as monotherapies or in combination. Many patients who have not had success in managing their symptoms with more conservative therapies may decide to resort to third-line treatments for refractory OAB. These treatments include neuromodulation therapies, particularly transvaginal electrical stimulation (TES) and sacral neuromodulation (SN). The aim of this short commentary is to provide an overview of the effectiveness of these treatments and of their impact on quality of life, body image, sexual function, and emotional well-being
Imaging the first light: experimental challenges and future perspectives in the observation of the Cosmic Microwave Background Anisotropy
Measurements of the cosmic microwave background (CMB) allow high precision
observation of the Last Scattering Surface at redshift 1100. After the
success of the NASA satellite COBE, that in 1992 provided the first detection
of the CMB anisotropy, results from many ground-based and balloon-borne
experiments have showed a remarkable consistency between different results and
provided quantitative estimates of fundamental cosmological properties. During
2003 the team of the NASA WMAP satellite has released the first improved
full-sky maps of the CMB since COBE, leading to a deeper insight into the
origin and evolution of the Universe. The ESA satellite Planck, scheduled for
launch in 2007, is designed to provide the ultimate measurement of the CMB
temperature anisotropy over the full sky, with an accuracy that will be limited
only by astrophysical foregrounds, and robust detection of polarisation
anisotropy. In this paper we review the experimental challenges in high
precision CMB experiments and discuss the future perspectives opened by second
and third generation space missions like WMAP and Planck.Comment: To be published in "Recent Research Developments in Astronomy &
Astrophysics Astrophysiscs" - Vol I
A multifrequency angular power spectrum analysis of the Leiden polarization surveys
The Galactic synchrotron emission is expected to be the most relevant source
of astrophysical contamination in cosmic microwave background polarization
measurements, at least at frequencies 30'. We
present a multifrequency analysis of the Leiden surveys, linear polarization
surveys covering essentially the Northern Celestial Hemisphere at five
frequencies between 408 MHz and 1411 MHz. By implementing specific
interpolation methods to deal with these irregularly sampled data, we produced
maps of the polarized diffuse Galactic radio emission with pixel size of 0.92
deg. We derived the angular power spectrum (APS) (PI, E, and B modes) of the
synchrotron dominated radio emission as function of the multipole, l. We
considered the whole covered region and some patches at different Galactic
latitudes. By fitting the APS in terms of power laws (C_l = k l^a), we found
spectral indices that steepen with increasing frequency: from a = -(1-1.5) at
408 MHz to a = -(2-3) at 1411 MHz for 10 < l < 100 and from a = -0.7 to a =
-1.5 for lower multipoles (the exact values depending on the considered sky
region and polarization mode). The bulk of this steepening can be interpreted
in terms of Faraday depolarization effects. We then considered the APS at
various fixed multipoles and its frequency dependence. Using the APSs of the
Leiden surveys at 820 MHz and 1411 MHz, we determined possible ranges for the
rotation measure, RM, in the simple case of an interstellar medium slab model.
Taking also into account the polarization degree at 1.4 GHz, we could break the
degeneracy between the identified RM intervals. The most reasonable of them
turned out to be RM = 9-17 rad/m^2.Comment: 18 pages, 14 figures. Astronomy and Astrophysics, in pres
The isolated Erebia pandrose Apennine population is genetically unique and endangered by climate change
Climate change is causing shifts in the distribution of many species and populations inhabiting mountain tops are particularly vulnerable to these threats because they are constrained in altitudinal shifts. Apennines are a relatively narrow and low mountain chain located in Southern Europe, which hosts many isolated populations of mountain species. The butterfly Erebia pandrose was recorded for the last time in the Apennines in 1977, on the top of a single massif (Monti della Laga).
We confirmed the presence of a small, isolated population of E. pandrose in the Apennines, at a distance of more than 400 km to any other known populations. Then, we examined the cytochrome c oxidase subunit 1 mitochondrial DNA marker of this species across the Palaearctic area and estimated the potential decline over the Alps and the Apennines due to future climatic changes.
The Apennine population represents an endemic lineage characterised by eight mutations over the 658 bp analysed (1.2%). In the Alps and Apennines, this species has shifted uphill more than 3 m per year since the end of the 19th century and more than 22 m per year since 1995. Species distribution models suggested that these mountain populations will experience a generalised loss of climatic suitability, which, according to our projections, could lead to the extinction of the Apennine population in a few decades.
Erebia pandrose has the potential to become a flagship species for advertising the risk of losing unique fractions of genetic diversity for mountain species
A polarized synchrotron template for CMBP experiments after WMAP data
We build template maps for the polarized Galactic--synchrotron emission on
large angular scales (FWHM =~7), in the 20-90 GHz microwave range, by
using WMAP data. The method, presented in a recent work, requires a synchrotron
total intensity survey and the {\it polarization horizon} to model the
polarized intensity and a starlight polarization map to model polarization
angles. The basic template is obtained directly at 23 GHz with about 94%
sky--coverage by using the synchrotron map released by the WMAP team.
Extrapolations to 32, 60 and 90 GHz are performed by computing a synchrotron
spectral index map, which strongly reduces previous uncertainties in passing
from low (1.4 GHz) to microwave frequencies. Differing from low frequency data,
none of our templates presents relevant structures out of the Galactic Plane.
Our map at 90 GHz suggests that the synchrotron emission at high Galactic
latitudes is low enough to allow a robust detection of the --mode component
of the cosmological signal on large--scale, even in models with
low--reionization (). Detection of the weaker --mode on the
largest scales () might be jeopardized unless the value found by WMAP is confirmed, and . For lower levels of the
gravitational--wave background the --mode seems to be accessible only at the
peak and in selected low--synchrotron emission areas.Comment: 13 pages, 14 figures, accepted for pubblications by MNRAS. For a
version with full resolution color figures see
http://sp0rt.bo.iasf.cnr.it:8080/Docs/Public/papers.ph
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