2,807 research outputs found
Assessing the adequacy of the bare optical potential in near-barrier fusion calculation
We critically examine the differences among the different bare nuclear
interactions used in near-barrier heavy ion fusion analysis and
Coupled-Channels calculations, and discuss the possibility of extracting the
barrier parameters of the bare potential from above-barrier data. We show that
the choice of the bare potential may be critical for the analysis of the fusion
cross sections. We show also that the barrier parameters taken from above
barrier data may be very wrong.Comment: 8 pages, 3 tables, 8 figures. Submitted to Physical Review
XMM-Newton and NuSTAR simultaneous X-ray observations of IGR J11215-5952
We report the results of an XMM-Newton and NuSTAR coordinated observation of
the Supergiant Fast X-ray Transient (SFXT) IGRJ11215-5952, performed on
February 14, 2016, during the expected peak of its brief outburst, which
repeats every about 165 days. Timing and spectral analysis were performed
simultaneously in the energy band 0.4-78 keV. A spin period of 187.0 +/- 0.4 s
was measured, consistent with previous observations performed in 2007. The
X-ray intensity shows a large variability (more than one order of magnitude) on
timescales longer than the spin period, with several luminous X-ray flares
which repeat every 2-2.5 ks, some of which simultaneously observed by both
satellites. The broad-band (0.4-78 keV) time-averaged spectrum was well
deconvolved with a double-component model (a blackbody plus a power-law with a
high energy cutoff) together with a weak iron line in emission at 6.4 keV
(equivalent width, EW, of 40+/-10 eV). Alternatively, a partial covering model
also resulted in an adequate description of the data. The source time-averaged
X-ray luminosity was 1E36 erg/s (0.1-100 keV; assuming 7 kpc). We discuss the
results of these observations in the framework of the different models proposed
to explain SFXTs, supporting a quasi-spherical settling accretion regime,
although alternative possibilities (e.g. centrifugal barrier) cannot be ruled
out.Comment: 13 pages, 11 figures, accepted for publication on The Astrophysical
Journa
Analogue Gravity and ultrashort laser pulse filamentation
Ultrashort laser pulse filaments in dispersive nonlinear Kerr media induce a
moving refractive index perturbation which modifies the space-time geometry as
seen by co-propagating light rays. We study the analogue geometry induced by
the filament and show that one of the most evident features of filamentation,
namely conical emission, may be precisely reconstructed from the geodesics. We
highlight the existence of favorable conditions for the study of analogue black
hole kinematics and Hawking type radiation.Comment: 4 pages, revised versio
Efalizumab-induced severe thrombocytopenia can be resolved
Efalizumab is a monoclonal a humanized recombinant IgG1 monoclonal antibody which targets the CD11a, the alpha-subunit of LFA-1 (lymphocyte function-associated antigen-1). It acts by blocking the T-lymphocyte pathogenetic mechanisms of psoriasis. Thrombocytopenia is an adverse event that occurs during therapy. Thrombocytopenia can be mild and can occur quite early during treatment, together with leukocytosis. Both adverse events tend to normalize with ongoing therapy, or, in cases worsening, with therapy suspension. There have been multiple reports of thrombocytopenia associated with efalizumab therapy for the treatment of psoriasis. The general recommendation is to check platelet counts monthly for the first 3 months of efalizumab therapy, then every 3 months for the duration of therapy. According to our experience on a wide range of patients, it is useful to check platelets every month for the first 6 months of therapy. We report a case of efalizumab-associated thrombocytopenia that occurred after 16 weeks of therapy together with clinical worsening of skin lesions. The peculiarity of our case is the absence of signs and symptoms linked to thrombocytopenia and the quick return to normal platelet count without corticosteroid therapy
Coexistence of pressure-induced structural phases in bulk black phosphorus: a combined x-ray diffraction and Raman study up to 18 GPa
We report a study of the structural phase transitions induced by pressure in
bulk black phosphorus by using both synchrotron x-ray diffraction for pressures
up to 12.2 GPa and Raman spectroscopy up to 18.2 GPa. Very recently black
phosphorus attracted large attention because of the unique properties of
fewlayers samples (phosphorene), but some basic questions are still open in the
case of the bulk system. As concerning the presence of a Raman spectrum above
10 GPa, which should not be observed in an elemental simple cubic system, we
propose a new explanation by attributing a key role to the non-hydrostatic
conditions occurring in Raman experiments. Finally, a combined analysis of
Raman and XRD data allowed us to obtain quantitative information on presence
and extent of coexistences between different structural phases from ~5 up to
~15 GPa. This information can have an important role in theoretical studies on
pressure-induced structural and electronic phase transitions in black
phosphorus
Energy Dependence of Breakup Cross Sections of Halo Nucleus 8B and Effective Interactions
We study the energy dependence of the cross sections for nucleon removal of
8B projectiles. It is shown that the Glauber model calculations with
nucleon-nucleon t-matrix reproduce well the energy dependence of the breakup
cross sections of 8B. A DWBA model for the breakup cross section is also
proposed and results are compared with those of the Glauber model. We show that
to obtain an agreement between the DWBA calculations, the Glauber formalism,
and the experimental data, it is necessary to modify the energy behavior of the
effective interaction. In particular, the breakup potential has a quite
different energy dependence than the strong absorption potential.Comment: 13 pages, 4 figure
On sample preparation methods for fermented beverage VOCs profiling by GCxGC-TOFMS
Introduction
Aromas and tastes have crucial influences on the quality of fermented beverages. The determination of aromatic compounds requires global non-targeted profiling of the volatile organic compounds (VOCs) in the beverages. However, experimental VOC profiling result depends on the chosen VOC collection method.
Objectives
This study aims to observe the impact of using different sample preparation techniques [dynamic headspace (DHS), vortex-assisted liquid–liquid microextraction (VALLME), multiple stir bar sorptive extraction (mSBSE), solid phase extraction (SPE), and solid phase micro-extraction (SPME)] to figure out the most suitable sample preparation protocol for profiling the VOCs from fermented beverages.
Methods
Five common sample preparation methods were studied with beer, cider, red wine, and white wine samples. After the sample preparation, collected VOCs were analyzed by two-dimensional gas chromatography coupled with time of flight mass spectrometry (GCxGC-TOFMS).
Results
GCxGC oven parameters can be optimized with the Box–Behnken surface response model and response measure on peak dispersion. Due to the unavoidable column and detector saturation during metabolomic analysis, errors may happen during mass spectrum construction. Profiling results obtained with different sample preparation methods show considerable variance. Common findings occupy a small fraction of total annotated VOCs. For known fermentative aromas, best coverage can be reached by using SPME together with SPE for beer, and VALLME for wine and cider.
Conclusions
GCxGC-TOFMS is a promising tool for non-targeted profiling on VOCs from fermented beverages. However, a proper data processing protocol is lacking for metabolomic analysis. Each sample preparation method has a specific profiling spectrum on VOC profiling. The coverage of the VOC metabolome can be improved by combining complementary methods
Estimate of the impact of background particles on the X-Ray Microcalorimeter Spectrometer on IXO
We present the results of a study on the impact of particles of galactic
(GCR) and solar origin for the X-ray Microcalorimeter Spectrometer (XMS) aboard
an astronomical satellite flying in an orbit at the second Lagrangian point
(L2). The detailed configuration presented in this paper is the one adopted for
the International X-Ray Observatory (IXO) study, however the derived estimates
can be considered a conservative limit for ATHENA, that is the IXO redefined
mission proposed to ESA. This work is aimed at the estimate of the residual
background level expected on the focal plane detector during the mission
lifetime, a crucial information in the development of any instrumental
configuration that optimizes the XMS scientific performances. We used the
Geant4 toolkit, a Monte Carlo based simulator, to investigate the rejection
efficiency of the anticoincidence system and assess the residual background on
the detector.Comment: 18 pages, 9 figure
Humanities in the undergraduate medical and midwifery curriculum: a descriptive Italian comparative study.
There is an increasing emphasis on humanized care in obstetric and midwifery practice. The goal of this paper is to investigate if and how medical humanities content was present in the undergraduate medical syllabus and how similar or different this is from the undergraduate midwifery program in Italy. A review of the 2017-18 curriculum for Italian Schools of Medicine and of Midwifery was carried out through institutional websites or mailing requests. The following details were collected for each program: the type of humanities content; the academic credits allocated, whether it was taught as a stand-alone (independent) topic or not, and the year(s) of the program when it was provided. Programs were included for 39 Schools of Medicine and 36 Schools of Midwifery. All midwifery schools included at least one subject with humanities content. Five medical schools (12.9) did not appear to have any subjects in this area. Psychology and ethics/bioethics were the most frequently found topics in both disciplines, but, apart from history of medicine, midwifery was much more likely than medicine to include other humanities topics, and especially pedagogy, anthropology, sociology and communication studies, philosophy and cross-cultural studies were rarely or never included in either discipline. A greater breadth of humanities studies was included in midwifery schools. However, their relative importance appears to be low, given the low level of academic credits and lack of presence as independent subjects
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