566 research outputs found
Secondary radiation from the Pamela/ATIC excess and relevance for Fermi
The excess of electrons/positrons observed by the Pamela and ATIC experiments
gives rise to a noticeable amount of synchrotron and Inverse Compton Scattering
(ICS) radiation when the e^+e^- interact with the Galactic Magnetic Field, and
the InterStellar Radiation Field (ISRF). In particular, the ICS signal produced
within the WIMP annihilation interpretation of the Pamela/ATIC excess shows
already some tension with the EGRET data. On the other hand, 1 yr of Fermi data
taking will be enough to rule out or confirm this scenario with a high
confidence level. The ICS radiation produces a peculiar and clean "ICS Haze"
feature, as well, which can be used to discriminate between the astrophysical
and Dark Matter scenarios. This ICS signature is very prominent even several
degrees away from the galactic center, and it is thus a very robust prediction
with respect to the choice of the DM profile and the uncertainties in the ISRF.Comment: 5 pages, 3 figures; v2: improved figures, enlarged discussion on the
gamma signal and data; to appear in ApJ
Ultrahigh energy neutrinos with a mediterranean neutrino telescope
A study of the ultra high energy neutrino detection performances of a km^3
Neutrino Telescope sitting at the three proposed sites for "ANTARES", "NEMO"
and "NESTOR" in the Mediterranean sea is here performed. The detected charged
leptons energy spectra, entangled with their arrival directions, provide an
unique tool to both determine the neutrino flux and the neutrino-nucleon cross
section.Comment: 10 pages, 10 figures, Proceedings of XII International Workshop on
Neutrino Telescopes, Venezia 200
Radio constraints on dark matter annihilation in the galactic halo and its substructures
Annihilation of Dark Matter usually produces together with gamma rays
comparable amounts of electrons and positrons. The e+e- gyrating in the
galactic magnetic field then produce secondary synchrotron radiation which thus
provides an indirect mean to constrain the DM signal itself. To this purpose,
we calculate the radio emission from the galactic halo as well as from its
expected substructures and we then compare it with the measured diffuse radio
background. We employ a multi-frequency approach using data in the relevant
frequency range 100 MHz-100 GHz, as well as the WMAP Haze data at 23 GHz. The
derived constraints are of the order =10^{-24} cm3 s^{-1} for a DM
mass m_chi=100 GeV sensibly depending however on the astrophysical
uncertainties, in particular on the assumption on the galactic magnetic field
model. The signal from single bright clumps is instead largely attenuated by
diffusion effects and offers only poor detection perspectives.Comment: 12 pages, 7 figures; v2: some references added, some discussions
enlarged; matches journal versio
High Energy Neutrinos with a Mediterranean Neutrino Telescope
The high energy neutrino detection by a km^3 Neutrino Telescope placed in the
Mediterranean sea provides a unique tool to both determine the diffuse
astrophysical neutrino flux and the neutrino-nucleon cross section in the
extreme kinematical region, which could unveil the presence of new physics.
Here is performed a brief analysis of possible NEMO site performances.Comment: 4 pages, 3 figures, Proceedings of the 30th ICRC 200
Disentangling neutrino-nucleon cross section and high energy neutrino flux with a km^3 neutrino telescope
The energy--zenith angular event distribution in a neutrino telescope
provides a unique tool to determine at the same time the neutrino-nucleon cross
section at extreme kinematical regions, and the high energy neutrino flux. By
using a simple parametrization for fluxes and cross sections, we present a
sensitivity analysis for the case of a km^3 neutrino telescope. In particular,
we consider the specific case of an under-water Mediterranean telescope placed
at the NEMO site, although most of our results also apply to an under-ice
detector such as IceCube. We determine the sensitivity to departures from
standard values of the cross sections above 1 PeV which can be probed
independently from an a-priori knowledge of the normalization and energy
dependence of the flux. We also stress that the capability to tag downgoing
neutrino showers in the PeV range against the cosmic ray induced background of
penetrating muons appears to be a crucial requirement to derive meaningful
constraints on the cross section.Comment: 10 pages, 28 figure
Regulation of p27kip1 and p57kip2 functions by natural polyphenols
In numerous instances, the fate of a single cell not only represents its peculiar outcome but also contributes to the overall status of an organism. In turn, the cell division cycle and its control strongly influence cell destiny, playing a critical role in targeting it towards a specific phenotype. Several factors participate in the control of growth, and among them, p27Kip1 and p57Kip2, two proteins modulating various transitions of the cell cycle, appear to play key functions. In this review, the major features of p27 and p57 will be described, focusing, in particular, on their recently identified roles not directly correlated with cell cycle modulation. Then, their possible roles as molecular effectors of polyphenols’ activities will be discussed. Polyphenols represent a large family of natural bioactive molecules that have been demonstrated to exhibit promising protective activities against several human diseases. Their use has also been proposed in association with classical therapies for improving their clinical effects and for diminishing their negative side activities. The importance of p27Kip1 and p57Kip2 in polyphenols’ cellular effects will be discussed with the aim of identifying novel therapeutic strategies for the treatment of important human diseases, such as cancers, characterized by an altered control of growth
A Beckwith–Wiedemann-associated CDKN1C mutation allows the identification of a novel nuclear localization signal in human p57Kip2
p57Kip2 protein is a member of the CIP/Kip family, mainly localized in the nucleus where it exerts its Cyclin/CDKs inhibitory function. In addition, the protein plays key roles in embryogenesis, differentiation, and carcinogenesis depending on its cellular localization and interactors. Mutations of CDKN1C, the gene encoding human p57Kip2, result in the development of different genetic diseases, including Beckwith–Wiedemann, IMAGe and Silver–Russell syndromes. We investigated a specific Beckwith–Wiedemann associated CDKN1C change (c.946 C>T) that results in the substitution of the C-terminal amino acid (arginine 316) with a tryptophan (R316W-p57Kip2). We found a clear redistribution of R316W-p57Kip2, in that while the wild-type p57Kip2 mostly occurs in the nucleus, the mutant form is also distributed in the cytoplasm. Transfection of two expression constructs encoding the p57Kip2 N-and C-terminal domain, respectively, allows the mapping of the nuclear localization signal(s) (NLSs) between residues 220–316. Moreover, by removing the basic RKRLR sequence at the protein C-terminus (from 312 to 316 residue), p57Kip2 was confined in the cytosol, implying that this sequence is absolutely required for nuclear entry. In conclusion, we identified an unreported p57Kip2 NLS and suggest that its absence or mutation might be of relevance in CDKN1C-associated human diseases determining significant changes of p57Kip2 localization/regulatory roles
Detection of Brucella abortus DNA and RNA in different stages of development of the sucking louse Haematopinus tuberculatus
Background: Brucellosis is considered the world’s most widespread zoonotic infection. It causes abortion and
sterility in livestock leading to serious economic losses and has even more serious medical impact in humans, since
it can be a trigger to more than 500,000 infections per year worldwide. The aim of this study was to evaluate the
role of Haematopinus tuberculatus, a louse that can parasitize several ruminants, as a new host of brucellosis. Louse
specimens were collected from seropositive and seronegative water buffaloes and divided in 3 developmental
stages: adults, nymphs and nits. All samples were separately screened for Brucella spp. DNA and RNA detection by
Real Time PCR. In particular, primers and probes potentially targeting the 16S rRNA and the Brucella Cell Surface
31 kDalton Protein (bcsp31) genes were used for Real Time PCR and buffalo β actin was used as a housekeeping
gene to quantify host DNA in the sample. A known amount of B. abortus purified DNA was utilized for standard
curve preparation and the target DNA amount was divided by the housekeeping gene amount to obtain a
normalized target value. A further molecular characterization was performed for Brucella strain typing and
genotyping by the Bruce-ladder, AMOS-PCR and MLVA assays. Data were statistically analysed by ANOVA.
Results: Brucella abortus DNA and RNA were detected in all developmental stages of the louse, suggesting the
presence of viable bacteria. Data obtained by MLVA characterization support this finding, since the strains present
in animals and the relative parasites were not always identical, suggesting bacterial replication. Furthermore, the
detection of Brucella DNA and RNA in nits samples demonstrate, for the first time, a trans-ovarial transmission of the
bacterium into the louse.
Conclusions: These findings identified H. tuberculatus as a new host of brucellosis. Further studies are needed to
establish the role of this louse in the epidemiology of the disease, such as vector or reservoir
- …