2,111 research outputs found
Supersymmetry without a light Higgs boson at the LHC
We analyze the LHC phenomenology of lambdaSUSY - a version of NMSSM with a
largish SH1H2 coupling. The scalar spectrum of the model contains a 200-300 GeV
Higgs boson h with Standard-Model like properties, and heavy CP-even and CP-odd
Higgs bosons H and A with masses in 500-800 GeV range. We study the discovery
potential of H and A in the decay chains H->hh->4V->2l6j and A->Zh->Z2V->2l4j.
The dominant backgrounds are the diffuse Z6j and Z4j productions, which can be
suppressed by demanding reconstruction of V's and h's in intermediate states.
The excess of signal events allows for a discovery of both H and A with over
5sigma significance for 100 inverse fb of integrated luminosity.Comment: 29 pages, 19 figure
Very High Energy gamma-rays from electron/positron Pair Halos
In this paper we study the formation of giant electrons-positron pair halos
around the powerful high energy extragalactic sources. We investigate the
dependence of radiation of pair halos, in particular the spectral and angular
distributions on the energy spectrum of the primary gamma-rays, the redshift of
the source, and the flux of the extragalactic background light.Comment: 17 pages, 17 figures, published in Volume No. 18, Issue No. 06 of
"International Journal Of Modern Physics D
The extended Malkus-Robbins dynamo as a perturbed Lorenz system
Recent investigations of some self-exciting Faraday-disk homopolar dynamo ([1-4]) have yielded the classic Lorenz equations as a special limit when one of the principal bifurcation parameters is zero. In this paper we focus upon one of those models [3] and illustrate what happens to some of the lowest order unstable periodic orbits as this parameter is increased from zero
Upper Limits on the Extragalactic Background Light from the Gamma-Ray Spectra of Blazars
The direct measurement of the extragalactic background light (EBL) is
difficult at optical to infrared wavelengths because of the strong foreground
radiation originating in the Solar System. Very high energy (VHE, E100 GeV)
gamma rays interact with EBL photons of these wavelengths through pair
production. In this work, the available VHE spectra from six blazars are used
to place upper limits on the EBL. These blazars have been detected over a range
of redshifts and a steepening of the spectral index is observed with increasing
source distance. This can be interpreted as absorption by the EBL. In general,
knowledge of the intrinsic source spectrum is necessary to determine the
density of the intervening EBL. Motivated by the observed spectral steepening
with redshift, upper limits on the EBL are derived by assuming that the
intrinsic spectra of the six blazars are . Upper limits are
then placed on the EBL flux at discrete energies without assuming a specific
spectral shape for the EBL. This is an advantage over other methods since the
EBL spectrum is uncertain.Comment: 33 pages, 14 figures, accepted by Ap
Nanofiller for the mechanical reinforcement of maltodextrins orodispersible films
One of the most critical quality attributes of orodispersible films (ODFs) is related to the development of dosage forms with tensile properties suitable for the packaging and patient's handling. Aiming to develop a strategy to reinforce the tensile properties, the current work reported the feasibility to improve the tensile strength of maltodextrins (MDX) based ODFs by adding an amorphous water insoluble nanofiller, namely polyvinylacetate (PVAc). The possible interactions between components investigated by DSC and ATR-FTIR spectroscopy revealed that MDX and PVAc were immiscible; even if, the presence of plasticizers permitted the homogeneous dispersion of PVAc in the film until the 10% w/w concentration was reached. As a consequence, PVAc nanoparticles was found to be an effective reinforcing agent only at the concentrations of 3 and 5% w/w. In this optimal range, the tensile strength increased at least 1.5 fold and the elastic modulus increased at least 4 times
Sexual functioning and opioid maintenance treatment in women. Results from a large multicentre study
Opioid maintenance treatment (OMT) is the most widespread therapy for both females and males opioid addicts. While many studies have evaluated the OMT impact on menâs sexuality, the data collected about the change in womenâs sexual functioning is still limited despite the fact that it is now well-known that opioids-both endogenous and exogenous-affect the endocrine system and play an important role in sexual functioning. The present study aims to determine how OMT with buprenorphine (BUP) or methadone (MTD) affects sexual health in women; examining also any possible emerging correlation between sexual dysfunction (SD), type of opioid and patientsâ mental health. This multi-center study case recruited 258 female volunteers attending Italian public Addiction Outpatients Centers that were stabilized with OMT for at least 3 months. SD was assessed with the Arizona Sexual Experience Scale. The twelve-item General Health Questionnaire was used to assess participantsâ mental health conditions. The results show that 56.6% of women receiving OMT for at least 3 months presented SD without significant differences between MTD e BUP groups. The majority of the subjects with SD have a poorer quality of intimate relationships and worse mental health than the average. To the best of our knowledge, the present study is the largest report on the presence of SDs in women as a side effects of MTD and BUP used in OMT. Since SDs cause difficulties in intimate relationships, lower patientsâ quality of life and interfere with OMT beneficial outcomes, we recommend that women undertaking an opioid therapy have routine screening for SD and we highlight the importance to better examine opioid-endocrine interactions in future studies in order to provide alternative potential treatments such as the choice of opioid, opioid dose reduction and hormone supplementation
Keck spectroscopy of z=1-3 ULIRGs from the Spitzer SWIRE survey
(Abridged) High-redshift ultra luminous infrared galaxies contribute the bulk
of the cosmic IR background and are the best candidates for very massive
galaxies in formation at z>1.5. We present Keck/LRIS optical spectroscopy of 35
z>1.4 luminous IR galaxies in the Spitzer Wide-area Infra-Red Extragalactic
survey (SWIRE) northern fields (Lockman Hole, ELAIS-N1, ELAIS-N2). The primary
targets belong to the ``IR-peak'' class of galaxies, having the 1.6 micron
(restframe) stellar feature detected in the IRAC Spitzer channels.The spectral
energy distributions of the main targets are thoroughly analyzed, by means of
spectro-photometric synthesis and multi-component fits (stars + starburst dust
+ AGN torus). The IR-peak selection technique is confirmed to successfully
select objects above z=1.4, though some of the observed sources lie at lower
redshift than expected. Among the 16 galaxies with spectroscopic redshift, 62%
host an AGN component, two thirds being type-1 and one third type-2 objects.
The selection, limited to r'<24.5, is likely biased to optically-bright AGNs.
The SEDs of non-AGN IR-peakers resemble those of starbursts (SFR=20-500
Msun/yr) hosted in massive (M>1e11 Msun) galaxies. The presence of an AGN
component provides a plausible explanation for the spectroscopic/photometric
redshift discrepancies, as the torus produces an apparent shift of the peak to
longer wavelengths. These sources are analyzed in IRAC and optical-IR color
spaces. In addition to the IR-peak galaxies, we present redshifts and spectral
properties for 150 objects, out of a total of 301 sources on slits.Comment: Accepted for publications on Astronomy and Astrophysics (acceprance
date March 8th, 2007). 33 pages. The quality of some figures have been
degrade
Mid-infrared sources in the ELAIS Deep X-ray Survey
We present a crossâcorrelation of the European Large Area Infrared Space Observatory (ISO) survey (ELAIS) with the ELAIS Deep Xâray Survey of the N1 and N2 fields. There are seven Chandra point sources with matches in the ELAIS Final Analysis 15âÎŒm catalogue, out of a total of 28 extragalactic ISO sources present in the Chandra fields. Five of these are consistent with active galactic nuclei (AGN) giving an AGN fraction of âŒ19 per cent in the 15âÎŒm flux range 0.8â6âmJy. We have coâadded the hard Xâray fluxes of the individually undetected ISO sources and find a low significance detection consistent with star formation in the remaining population. We combine our point source crossâcorrelation fraction with the XMMâNewton observations of the Lockman Hole and Chandra observations of the Hubble Deep Field North to constrain source count models of the midâinfrared galaxy population. The low dustâenshrouded AGN fraction in ELAIS implied by the number of crossâidentifications between the ELAIS midâinfrared sample and the Chandra point sources is encouraging for the use of midâinfrared surveys to constrain the cosmic star formation history, provided there are not further large undetected populations of Comptonâthick AGN
Diversity in EWAS: current state, challenges, and solutions
Here, we report a lack of diversity in epigenome-wide association studies (EWAS) and DNA methylation (DNAm) data, discuss current challenges, and propose solutions for EWAS and DNAm research in diverse populations. The strategies we propose include fostering community involvement, new data generation, and cost-effective approaches such as locus-specific analysis and ancestry variable region analysis
Mid- and Far-infrared Luminosity Functions and Galaxy Evolution from Multiwavelength Spitzer Observations up to z~2.5
[Abridged]We exploit a large homogeneous dataset to derive a self-consistent
picture of IR emission based on the time-dependent 24, 15, 12 and 8micron
monochromatic and bolometric IR luminosity functions (LF) over the 0<z<2.5
redshift range. Our analysis is based on the combination of data from deep
Spitzer surveys in the VVDS-SWIRE and GOODS areas. To our limiting flux of
S(24)=400microJy our derived sample in VVDS-SWIRE includes 1494 sources, and
666 and 904 sources brighter than S(24)=80microJy are catalogued in GOODS-S and
GOODS-N, respectively, for a total area of ~0.9 square degs. We obtain reliable
optical identifications and redshifts, providing us a rich and robust dataset
for our luminosity function determination. Based on the multi-wavelength
information available, we constrain the LFs at 8, 12, 15 and 24micron. We also
extrapolate total IR luminosities from our best-fit to the observed SEDs of
each source, and use this to derive the bolometric LF and comoving volume
emissivity up to z~2.5. In the 0<z<1 interval, the bolometric IR luminosity
density evolves as (1+z)^3.8+/-0.4. Although more uncertain at higher-z, our
results show a flattening of the IR luminosity density at z>1. The mean
redshift of the peak in the source number density shifts with luminosity: the
brighest IR galaxies appear to be forming stars earlier in cosmic time (z>1.5),
while the less luminous ones keep doing it at more recent epochs (z~1 for
L(IR)<10^11L_sun). Our results suggest a rapid increase of the galaxy IR
comoving volume emissivity back to z~1 and a constant average emissivity at
z>1. We also seem to find a difference in the evolution rate of the source
number densities as a function of luminosity, a downsizing evolutionary pattern
similar to that reported from other samples of cosmic sources.Comment: Accepted for pubblicantion in Astronomy and Astrophysic
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