758 research outputs found
Annihilation of NMSSM neutralinos in the Sun and neutrino telescope limits
We investigate neutralino dark matter in the framework of NMSSM performing a
scan over its parameter space and calculating neutralino capture and
annihilation rates in the Sun. We discuss the prospects of searches for
neutralino dark matter in neutrino experiments depending on neutralino content
and its main annihilation channel. We recalculate the upper limits on
neutralino-proton elastic cross sections directly from neutrino telescopes
upper bounds on annihilation rates in the Sun. This procedure has advantages as
compared with corresponding recalcalations from the limits on muon flux,
namely, it is independent on details of the experiment and the recalculation
coefficients are universal for any kind of WIMP dark matter models. We derive
90% c.l. upper limits on neutralino-proton cross sections from the results of
the Baksan Underground Scintillator Telescope.Comment: 28 pages, 16 figures, accepted for publication in JCAP, references
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Limits on the high-energy gamma and neutrino fluxes from the SGR 1806-20 giant flare of December 27th, 2004 with the AMANDA-II detector
On December 27th 2004, a giant gamma flare from the Soft Gamma-ray Repeater
1806-20 saturated many satellite gamma-ray detectors. This event was by more
than two orders of magnitude the brightest cosmic transient ever observed. If
the gamma emission extends up to TeV energies with a hard power law energy
spectrum, photo-produced muons could be observed in surface and underground
arrays. Moreover, high-energy neutrinos could have been produced during the SGR
giant flare if there were substantial baryonic outflow from the magnetar. These
high-energy neutrinos would have also produced muons in an underground array.
AMANDA-II was used to search for downgoing muons indicative of high-energy
gammas and/or neutrinos. The data revealed no significant signal. The upper
limit on the gamma flux at 90% CL is dN/dE < 0.05 (0.5) TeV^-1 m^-2 s^-1 for
gamma=-1.47 (-2). Similarly, we set limits on the normalization constant of the
high-energy neutrino emission of 0.4 (6.1) TeV^-1 m^-2 s^-1 for gamma=-1.47
(-2).Comment: 14 pages, 3 figure
Mitochondrial precursor proteins are imported through a hydrophilic membrane environment
We have analyzed how translocation intermediates of imported mitochondrial precursor proteins, which span contact sites, interact with the mitochondrial membranes. F1-ATPase subunit β(F1β) was trapped at contact sites by importing it into Neurospora mitochondria in the presence of low levels of nucleoside triphosphates. This F1β translocation intermediate could be extracted from the membranes by treatment with protein denaturants such as alkaline pH or urea. By performing import at low temperatures, the ADP/ATP carrier was accumulated in contact sites of Neurospora mitochondria and cytochrome b2 in contact sites of yeast mitochondria. These translocation intermediates were also extractable from the membranes at alkaline pH. Thus, translocation of precursor proteins across mitochondrial membranes seems to occur through an environment which is accessible to aqueous perturbants. We propose that proteinaceous structures are essential components of a translocation apparatus present in contact sites
High Energy Neutrino Telescopes
This paper presents a review of the history, motivation and current status of
high energy neutrino telescopes. Many years after these detectors were first
conceived, the operation of kilometer-cubed scale detectors is finally on the
horizon at both the South Pole and in the Mediterranean Sea. These new
detectors will perhaps provide us the first view of high energy astrophysical
objects with a new messenger particle and provide us with our first real
glimpse of the distant universe at energies above those accessible by gamma-ray
instruments. Some of the topics that can be addressed by these new instruments
include the origin of cosmic rays, the nature of dark matter, and the
mechanisms at work in high energy astrophysical objects such as gamma-ray
bursts, active galactic nuclei, pulsar wind nebula and supernova remnants.Comment: 33 pages, 21 figures, accepted for publication in the New Journal of
Physic
A qualitative reading of the ecological (dis)organisation of criminal associations. The case of the ?Famiglia Basilischi? in Italy
This paper combines the theoretical foundations of organisational ecology - one of the most important approaches in economic sociology - with classic criminological theories to interpret the birth, evolution and death of criminal associations. This mixed approach will support the interpretation of organised crime groups as phenomena strictly linked to the environment as well as to other competitors in criminal markets. This paper analyses the birth, evolution and death of a criminal association in Basilicata, Southern Italy, known as the ?Famiglia Basilischi?. The case is exemplary of how ecological conditions affect the success or failure of a newly formed criminal association. These conditions can therefore be indicators to interpret organised criminal activities in similar environments
Structural Basis for the Aminoacid Composition of Proteins from Halophilic Archea
In order to survive in highly saline environments, proteins from halophilic archea have evolved with biased amino acid compositions that have the capacity to reduce contacts with the solvent
Tumoral CD105 is a novel independent prognostic marker for prognosis in clear-cell renal cell carcinoma
International audienceBackground: Angiogenesis is essential for tumour growth and metastasis. There are conflicting reports as to whether microvessel density (MVD) using the endothelial marker CD105 (cluster of differentiation molecule 105) in clear-cell renal cell carcinomas (ccRCC) is associated with prognosis. Recently, CD105 has been described as a RCC cancer stem cell marker.Methods: A total of 102 ccRCC were analysed. Representative tumour sections were stained for CD105. Vascularity (endothelial CD105) was quantified by MVD. The immunohistochemistry analysis detected positive (if present) or negative (if absent) CD105 tumoral staining. This retrospective population-based study was evaluated using Kaplan–Meier method, t-test and Cox proportional hazard model.Results: We found that the expression of endothelial CD105 (MVD) negatively correlated with nuclear grade (P<0.001), tumour stage (P<0.001) and Leibovitch score (P<0.001), whereas the expression of tumoral CD105 positively correlated with these three clinicopathological factors (P<0.001). In multivariate analysis, tumoral CD105 was found to be an independent predictor of poor overall survival (P=0.002).Conclusions: We have shown for the first time that tumoral CD105 is an independent predictive marker for death risk and unfavourable prognosis in patients with ccRCC after curative resection
Effect of Smoking on Circulating Angiogenic Factors in High Risk Pregnancies
Objective: Changes in maternal concentrations of the anti-angiogenic factors, soluble fms-like tyrosine kinase 1 (sFlt1) and soluble endoglin (sEng), and the pro-angiogenic placental growth factor (PlGF) precede the development of preeclampsia in healthy women. The risk of preeclampsia is reduced in women who smoke during pregnancy. The objective of this study was to investigate whether smoking affects concentrations of angiogenic factors (sFlt1, PlGF, and sEng) in women at high risk for developing preeclampsia. Study Design: We performed a secondary analysis of serum samples from 993 high-risk women (chronic hypertension, diabetes, multifetal gestation, and previous preeclampsia) in a preeclampsia prevention trial. sFlt1, sEng and PlGF were measured in serum samples obtained at study entry, which was prior to initiation of aspirin (median 19.0 weeks' [interquartile range of 16.0-22.6 weeks']). Smoking status was determined by self-report. Results: sFlt1 was not significantly different in smokers from any high-risk groups compared to their nonsmoking counterparts. PlGF was higher among smokers compared to nonsmokers among diabetic women (142.7 [77.4-337.3] vs 95.9 [48.5-180.7] pg/ml, p = 0.005) and women with a history of preeclampsia (252.2 [137.1-486.0] vs 152.2 [73.6-253.7] pg/ml, p = 0.001). sEng was lower in smokers with multifetal gestations (5.8 [4.6-6.5] vs 6.8 [5.5-8.7] ng/ml, p = 0.002) and trended lower among smokers with diabetes (4.9 [3.8-5.6] vs 5.3 [4.3-6.3] ng/ml, p = 0.05). Smoking was not associated with a lower incidence of preeclampsia in any of these groups. Conclusions: In certain high-risk groups, smoking is associated with changes in the concentrations of these factors towards a pro-angiogenic direction during early pregnancy; however, there was no apparent association between smoking and the development of preeclampsia in our cohort
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