336 research outputs found
3He/4He isotopic ratio characterization of the Polynesian region: the society and upper Cook-Austral chains
We report the result of a systematic survey of the helium isotopic composition for basaltic rocks from the Polynesian region. The database covering the Society chain lists 79 entries deriving from experiments carried out at SIO (Scripps Institution of Oceanography, University of California San Diego, CA, USA) following the procedure of crushing on-line with an 8 minute single step; data for the
Cook-Austral islands are taken from the literature. The 3He/4He value distribution shows an intrinsic dispersion s between 1.1 and 1.4 times RA (RA= 3He/4He in Air = 1.3931026) and appears sensibly uniform over the area explored, clearly independent from the variation of age (0 to 20 My) along the dorsal of the Island chains. The difference appearing between the mean value obtained for the Society (R/RA = 6.361) and the Cook-Austral (R/RA = 7.361.4) is not appreciable within the “natural” dispersion. The values obtained are substantially lower than the Pacific MORB (R/RAA8.7 RA). No evident correlation appears in the general picture between the helium data and the other radiogenic isotopes interpreted as tracers for
possible heterogeneity in the mantle
Giuseppe Occhialini: Il secondo periodo italiano (1950-1993)
This paper gives an overview of the role Giuseppe Occhialini played in the field of cosmic physics in the period 1950-1993
The extreme universe of cosmic rays: Observations from space
The space mission “Extreme Universe Space Observatory—EUSO”
is devoted to the investigation of the Extreme Energy Cosmic Rays (EECR with E > 5 × 1019 eV)and of the high energy cosmic neutrino flux. EUSO will observe the streak of UV fluorescence light produced when the particles coming from outer space interact with the Earth’s atmosphere, looking downward from space the dark Earth atmosphere under a 60 degrees full field of view. The fluorescence light will
be imaged by a large Fresnel lens optics into a finely segmented focal plane detector. The segmentation and the time resolution adopted will consent to reconstruct the
shower arrival direction and energy with high precision. EUSO is a collaborating effort of research groups from Europe, USA and Japan and it has been designed to operate for more than 3 years mission life-time; it is expected to detect of the order of 103/year EECRs with E > 1020 eV and to open a window into the high energy neutrino astronomy. Originally proposed to the European Space Agency as a
free-flyer low-earth orbit mission, EUSO has been approved by ESA in March 2000 for an accommodation study on the international space station, with a goal for a flight starting in mid 2006
EUSO: using high energy cosmic rays and neutrinos as messengers from the unknown universe
Exploiting the earth atmosphere as a giant detector for the incoming extraterrestrial fl ux of high energy cosmic rays
and cosmic neutrinos, the mission «EUSO-Extreme Universe Space Observatory» is devoted to the exploration
of the domain of the highest energy processes occurring in the universe up to its accessible boundaries. The
observable is provided by the air nitrogen fl uorescence light emitted in the UV band 300-400 nm by the extensive
air showers produced by the cascading processes of the primary cosmic radiation particles interacting with the
atmosphere. The EUSO telescope is based on a double Fresnel lens optics (diameter 2.5 m) coupled to a highly
pixelized focal surface composed multianode PMTs; the image at the earth surface is detailed at 1 km2 over a total
of several hundred thousand of km2. EUSO will fl y on the International Space Station accommodated as external
payload of the European Space Agency Columbus module. The mission is scheduled to last 3 years, with the start
of operations foreseen for 2007/8. The expectations are of a collection rate of a thousand events/year for cosmic
rays at E > 1020 eV together with tens/hundreds of cosmic neutrinos at energy above about 4 ¥ 1019 eV. EUSO is
the result of the collaborative effort of several institutions in Europe, Japan and USA and it is conceived within
the science program sponsored by various space agencies coordinated by ESA
Reduced T-cell repertoire restrictions in abatacept-treated rheumatoid arthritis patients.
BACKGROUND: CD28(neg) T cells, which display functional characteristic of oligoclonally expanded cytotoxic memory T lymphocytes, are believed to be pathologically relevant in rheumatoid arthritis manifestation. The CD28 co-stimulation blockade by abatacept can prevent the generation of CD28(neg) T-cell populations in these patients.
METHODS: Samples were obtained before and after 12 months of abatacept therapy. T-cell phenotype and T-cell receptor diversity were evaluated by flow cytometry and complementarity-determining region-3 spectratyping, respectively, while telomerase reverse-transcriptase gene level was measured by real-time PCR.
RESULTS: Abatacept induces a decrease of the percentage and number of CD4(+)CD28(neg) T cells and a reduction of T-cell repertoire restrictions; these features are directly correlated. Thymic output and telomerase activity are not modified by the therapy.
CONCLUSIONS: Abatacept-induced decrease of peripheral T-cell repertoire restrictions can due to a reduced generation of senescent, chronically stimulated CD4(+)CD28(neg) T cells
A Pharmacist-Led Medication Switch Protocol in an Academic HIV Clinic: Patient Knowledge and Satisfaction
BACKGROUND: Tenofovir alafenamide (TAF) is associated with less renal and bone toxicity compared with tenofovir disoproxil (TDF). TAF\u27s recent FDA approval has spurred HIV providers to consider switching antiretroviral therapy (ART) regimens containing TDF to TAF to minimize long term risks. Patient views on the process of such medication switches have not been explored.
METHODS: Patients taking elvitegravir/cobicistat/emtricitabine/tenofovir disoproxil fumarate (E/C/F/TDF) following the Food and Drug Administration\u27s (FDA) approval of elvitegravir/cobicistat/emtricitabine/tenofovir alafenamide (E/C/F/TAF) received medication education from an HIV pharmacist prior to switching to the tenofovir alafenamide (TAF) formulation. Patients were asked to complete a cross-sectional survey assessing satisfaction with the switch process and knowledge about the new medication 4 to 8 weeks post-switch.
RESULTS: Sixty five patients completed the switch and 57 (88%) completed a follow-up survey. Most (86%) reported understanding why the switch was made, while 91% correctly identified that TAF is associated with reduced renal toxicity, and 73% correctly identified that TAF is associated with reduced bone toxicity. No statistically significant difference was found in satisfaction with or understanding of why the medication switch was made when assessed by sex, age, race, or education, but there was a trend toward significance in the distribution of answers based on education level with those with a high school diploma, General Educational Development (GED) or less being more likely to be satisfied with the medication switch (p = 0.074).
CONCLUSIONS: Education from an ambulatory clinic-based HIV pharmacist resulted in high rates of patient satisfaction and understanding of the switch from TDF to TAF-containing ART
Observing Ultra High Energy Cosmic Particles from Space: SEUSO, the Super Extreme Universe Space Observatory Mission
The experimental search for ultra high energy cosmic messengers, from eV to beyond eV, at the very end of the known energy
spectrum, constitutes an extraordinary opportunity to explore a largely unknown
aspect of our universe. Key scientific goals are the identification of the
sources of ultra high energy particles, the measurement of their spectra and
the study of galactic and local intergalactic magnetic fields. Ultra high
energy particles might, also, carry evidence of unknown physics or of exotic
particles relics of the early universe. To meet this challenge a significant
increase in the integrated exposure is required. This implies a new class of
experiments with larger acceptances and good understanding of the systematic
uncertainties. Space based observatories can reach the instantaneous aperture
and the integrated exposure necessary to systematically explore the ultra high
energy universe. In this paper, after briefly summarising the science case of
the mission, we describe the scientific goals and requirements of the SEUSO
concept. We then introduce the SEUSO observational approach and describe the
main instrument and mission features. We conclude discussing the expected
performance of the mission
Deadly Puppy Infection Caused by an MDR Escherichia coli O39 blaCTX–M–15, blaCMY–2, blaDHA–1, and aac(6)-Ib-cr – Positive in a Breeding Kennel in Central Italy
Antimicrobial consumption in veterinary medicine has led to the spread of multi drug-resistance in clinically important bacteria, with the companion animals and their environment involved as emerging reservoirs. While CTX-M-15 and CMY-2 acquired β-lactamases have been widely detected in the bacterial population of companion and breeding animals in European area, DHA-1 enzymes have been rarely reported in veterinary medicine. The aim of the study was to characterize the Escherichia coli associated with mortality of a litter of Bulldog puppies in a breeding kennel located in Pesaro area, Central Italy. The E. coli strains O39 serotype were resistant to 3rd/4th generation cephalosporins, chloramphenicol, aminoglycosides, trimethoprim-sulfamethoxazole, and ciprofloxacin, retaining susceptibility to carbapenems, colistin, fosfomycin, and levofloxacin (by Microscan Autoscan4, EUCAST clinical breakpoints). Pulse field gel electrophoreses (PFGE-XbaI) on five E. coli strains revealed the presence of a single profile. Whole genome sequencing (WGS) analysis revealed a complex resistome, harboring blaTEM–1b, blaCTX–M–15, blaOXA–1, aph(6)-Ib, aac(6′)Ib-cr, aac(3)-Ila, aph(6)-Id, aadA1, qnrB1, sul2, catA1, catB3, tetA, and dfrA14 genes located on a 302597 bp IncHI2/HI2A plasmid. Moreover, blaDHA–1, qnrB4, mph(A), sul1, and dfrA17 determinants were carried on an 83,429 bp IncFII plasmid. A blaCMY–2 determinant was carried on a 90,249 bp IncI1 plasmid. Two IncX1 and IncX4 plasmids without antimicrobial resistance genes were also detected. The presence of lpfA, iss, astA, and gad virulence factors was highlighted. This is the first report in Italy on an invasive infection in eight 2-weeks old dogs caused by the same MDR E. coli O39 blaCTX–M–15, blaCMY–2, blaDHA–1, and aac(6′)-Ib-cr positive strain. The above MDR E. coli clone caused the death of the entire litter, despite amoxicillin-clavulanate and enrofloxacin administration. The tank for storage of the water used to prepare the milk-based meal for the litter was the suspected reservoir
SUSY Resonances from UHE neutralinos in Neutrino Telescopes and in the Sky
In the Top-down scenarios, the decay of super-heavy particles
(m~10^{12-16}GeV), situated in dark-matter halos not very far from our Galaxy,
can explain the ultra-high-energy (UHE) cosmic-ray spectrum beyond the
Griesen-Zatasepin-Kuzmin cut-off. In the MSSM, a major component of the UHE
cosmic-ray flux at PeV-EeV energies could be given by the lightest neutralino
\chi, that is the lightest stable supersymmetric particle. Then, the signal of
UHE \chi's on earth might emerge over the interactions of a comparable neutrino
component. We compute the event rates for the resonant production of "right"
selectrons and "right" squarks in mSUGRA, when UHE neutralinos of energy larger
than 10^5 GeV scatter off electrons and quarks in an earth-based detector like
IceCube. When the resonant channel dominates in the total \chi-e,\chi-q
scattering cross section, the only model parameters affecting the corresponding
visible signal rates turn out to be the physical masses of the resonant
right-scalar and of the lightest neutralino. We compare the expected number of
supersymmetric events with the rates corresponding to the expected Glashow W
resonance and to the continuum UHE \nu-N scattering for realistic power-law
spectra. We find that the event rate in the leptonic selectron channel is
particularly promising, and can reach a few tens for a one-year exposure in
IceCube. Finally, we note that UHE neutralinos at much higher energies (up to
hundreds ZeV) may produce sneutrino resonances by scattering off relic
neutrinos in the Local Group hot dark halo. The consequent \tilde{\nu}-burst
into hadronic final states could mimic Z-burst events, although with quite
smaller conversion efficiency.Comment: 23 pages, 4 figures; one reference adde
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