301 research outputs found
INTEGRAL broadband spectroscopy of Vela X-1
The wind-accreting X-ray binary pulsar and cyclotron line source Vela X-1 has
been observed extensively during INTEGRAL Core Program observations of the Vela
region in June-July and November-December 2003. In the latter set of
observations the source showed intense flaring -- see also Staubert et al.
(2004), these proceedings.
We present early results on time averaged and time resolved spectra, of both
epochs of observations. A cyclotron line feature at ~53 keV is clearly detected
in the INTEGRAL spectra and its broad shape is resolved in SPI spectra. The
remaining issues in the calibration of the instruments do not allow to resolve
the question of the disputed line feature at 20-25 keV.
During the first main flare the average luminosity increases by a factor of
\~10, but the spectral shape remains very similar, except for a moderate
softening.Comment: Accepted for proceedings of 5th INTEGRAL Worksho
Performances of Anode-resistive Micromegas for HL-LHC
Micromegas technology is a promising candidate to replace Atlas forward muon
chambers -tracking and trigger- for future HL-LHC upgrade of the experiment.
The increase on background and pile-up event probability requires detector
performances which are currently under studies in intensive RD activities.
We studied performances of four different resistive Micromegas detectors with
different read-out strip pitches. These chambers were tested using \sim120 GeV
momentum pions, at H6 CERN-SPS beam line in autumn 2010. For a strip pitch 500
micrometers we measure a resolution of \sim90 micrometers and a efficiency of
~98%. The track angle effect on the efficiency was also studied. Our results
show that resistive techniques induce no degradation on the efficiency or
resolution, with respect to the standard Micromegas. In some configuration the
resistive coating is able to reduce the discharge currents at least by a factor
of 100.Micromegas technology is a promising candidate to replace Atlas forward
muon chambers -tracking and trigger- for future HL-LHC upgrade of the
experiment. The increase on background and pile-up event probability requires
detector performances which are currently under studies in intensive RD
activities. We studied performances of four different resistive Micromegas
detectors with different read-out strip pitches. These chambers were tested
using \sim120 GeV momentum pions, at H6 CERN-SPS beam line in autumn 2010. For
a strip pitch 500 micrometers we measure a resolution of \sim90 micrometers and
a efficiency of \sim98%. The track angle effect on the efficiency was also
studied. Our results show that resistive techniques induce no degradation on
the efficiency or resolution, with respect to the standard Micromegas. In some
configuration the resistive coating is able to reduce the discharge currents at
least by a factor of 100.Comment: "Presented at the 2011 Hadron Collider Physics symposium (HCP-2011),
Paris, France, November 14-18 2011, 3 pages, 6 figures.
Spatial distribution and statistical properties of small-scale convective vortex-like motions in a quiet Sun region
High-resolution observations of a quiet Sun internetwork region taken with
the Solar 1-m Swedish Telescope in La Palma are analyzed. We determine the
location of small-scale vortex motions in the solar photospheric region by
computing the horizontal proper motions of small-scale structures on time
series of images. These plasma convectively-driven swirl motions are associated
to: (1) downdrafts (that have been commonly explained as corresponding to sites
where the plasma is cooled down and hence returned to the interior below the
visible photospheric level), and (2) horizontal velocity vectors converging
into a central point. The sink cores are proved to be the final destination of
passive floats tracing plasma flows towards the center of each vortex. We
establish the occurrence of these events to be 1.4 x 10^(-3) and 1.6 x 10^(-3)
vortices Mm^(-2) min^(-1) respectively for two time series analyzed here.Comment: 8 pages, 6 figures. Accepted for publication in Monthly Notices of
the Royal Astronomical Societ
Prenatal counseling of an isolated fetal small head circumference during the second trimester expert ultrasound examination
Objective: To evaluate perinatal and postnatal outcomes of fetuses with an isolated small head circumference (HC) on expert ultrasound examination in the second trimester for further recommendations in prenatal care. Study Design: In a retrospective cohort we included singleton-pregnancies with a fetal HC > â3.0 SD and †â1.64 SD determined on expert ultrasound examination between 18 and 24 weeks of gestational age. Three subgroups were determined: âisolated small HC (ISHC)â, âsmall HC plus abdominal circumference (AC) †p10 (SHC+)â and âsmall HC plus AC †p10 and Doppler abnormalities (SHC + D)â. After ultrasound examination, genetic testing was sometimes offered and postnatally genetic tests were performed on indication. Results: We included 252 pregnancies: 109 ISHC, 104 SHC+, and 39 SHC + D. In the ISHC and SHC+ subgroup, 96 % of the fetuses were born alive and did not die neonatal. In the SH + D group this was only 38 %. In the SHC+ subgroup, less fetuses were delivered vaginal (non-instrumental) compared to the ISHC subgroup (61 % vs. 73 %, p < 0.01). In the ISHC and SHC+ subgroup s some fetuses were diagnosed with congenital defects (4 % vs. 10 %, p = 0.08) and with a genetic anomaly (6.4 % vs. 7.7 %, p = 0.13) after 24 weeks or postnatally. In SHC + D subgroups 5 % presented with congenital defects and 2.6 % with a genetic anomaly. Conclusion: We conclude that fetuses with a small HC without structural anomalies on second trimester expert ultrasound require follow-up and special medical attention. We recommend differentiating between ISHC, SHC+, and SHC + D for prenatal counseling. Genetic testing and referral to a clinical geneticist should be considered.</p
Prenatal counseling of an isolated fetal small head circumference during the second trimester expert ultrasound examination
Objective: To evaluate perinatal and postnatal outcomes of fetuses with an isolated small head circumference (HC) on expert ultrasound examination in the second trimester for further recommendations in prenatal care. Study Design: In a retrospective cohort we included singleton-pregnancies with a fetal HC > â3.0 SD and †â1.64 SD determined on expert ultrasound examination between 18 and 24 weeks of gestational age. Three subgroups were determined: âisolated small HC (ISHC)â, âsmall HC plus abdominal circumference (AC) †p10 (SHC+)â and âsmall HC plus AC †p10 and Doppler abnormalities (SHC + D)â. After ultrasound examination, genetic testing was sometimes offered and postnatally genetic tests were performed on indication. Results: We included 252 pregnancies: 109 ISHC, 104 SHC+, and 39 SHC + D. In the ISHC and SHC+ subgroup, 96 % of the fetuses were born alive and did not die neonatal. In the SH + D group this was only 38 %. In the SHC+ subgroup, less fetuses were delivered vaginal (non-instrumental) compared to the ISHC subgroup (61 % vs. 73 %, p < 0.01). In the ISHC and SHC+ subgroup s some fetuses were diagnosed with congenital defects (4 % vs. 10 %, p = 0.08) and with a genetic anomaly (6.4 % vs. 7.7 %, p = 0.13) after 24 weeks or postnatally. In SHC + D subgroups 5 % presented with congenital defects and 2.6 % with a genetic anomaly. Conclusion: We conclude that fetuses with a small HC without structural anomalies on second trimester expert ultrasound require follow-up and special medical attention. We recommend differentiating between ISHC, SHC+, and SHC + D for prenatal counseling. Genetic testing and referral to a clinical geneticist should be considered.</p
The role of confined placental mosaicism in fetal growth restriction:A retrospective cohort study
Objective: To evaluate which cytogenetic characteristics of confined placental mosaicism (CPM) detected in the first trimester chorionic villi and/or placentas in terms of chromosome aberration, cell lineage involved and trisomy origin will lead to fetal growth restriction and low birthweight. Methods: Cohort study using routinely collected perinatal data and cytogenetic data of non-invasive prenatal testing, the first trimester chorionic villi sampling and postnatal placentas. Results: 215 CPM cases were found. Fetal growth restriction (FGR) and low birthweight below the 10 th percentile (BWÂ <Â p10) were seen in 34.0% and 23.1%, respectively. Excluding cases of trisomy 16, 29.1% showed FGR and 17.9% had a BWÂ <Â p10. The highest rate of FGR and BWÂ <Â p10 was found in CPM type 3, but differences with type 1 and 2 were not significant. FGR and BWÂ <Â p10 were significantly more often observed in cases with meiotic trisomies. Conclusion: There is an association between CPM and FGR and BWÂ <Â p10. This association is not restricted to trisomy 16, neither to CPM type 3, nor to CPM involving a meiotic trisomy. Pregnancies with all CPM types and origins should be considered to be at increased risk of FGR and low BWÂ <Â p10. A close prenatal fetal monitoring is indicated in all cases of CPM.</p
Luspatercept improves hemoglobin levels and blood transfusion requirements in a study of patients with b-thalassemia
b-thalassemia is a hereditary disorder with limited approved treatment options; patients experience anemia and its complications, including iron overload. The study aim was to determine whether luspatercept could improve anemia and disease complications in patients with b-thalassemia. This open-label, nonrandomized, uncontrolled study consisted of a 24-week dose-finding and expansion stage (initial stage) and a 5-year extension stage, currently ongoing. Sixty-four patients were enrolled; 33 were non\u2013transfusion dependent (mean hemoglobin, <10.0 g/dL; <4 red blood cell [RBC] units transfused per 8 weeks), and 31 were transfusion dependent (\u20214 RBC units per 8 weeks). Patients received 0.2 to 1.25 mg/kg luspatercept subcutaneously every 21 days for \u20215 cycles (dose-finding stage) and 0.8 to 1.25 mg/kg (expansion cohort and 5-year extension). The primary end point was erythroid response, defined as hemoglobin increase of \u20211.5 g/dL from baseline for \u202114 consecutive days (without RBC transfusions) for non\u2013transfusion-dependent patients or RBC transfusion burden reduction \u202120% over a 12-week period vs the 12 weeks before treatment for transfusion-dependent patients. Eighteen non\u2013transfusion-dependent patients (58%) receiving higher dose levels of luspatercept (0.6-1.25 mg/kg) achieved mean hemoglobin increase \u20211.5 g/dL over \u202114 days vs baseline. Twenty-six (81%) transfusion-dependent patients achieved \u202120% reduction in RBC transfusion burden. The most common grade 1 to 2 adverse events were bone pain, headache, and myalgia. As of the cutoff, 33 patients remain on study. In this study, a high percentage of b-thalassemia patients receiving luspatercept had hemoglobin or transfusion burden improvements. These findings support a randomized clinical trial to assess efficacy and safety. This study was registered at www.clinicaltrials.gov as #NCT01749540 and #NCT02268409
-boson polarization as a model-discrimination analyzer
Determining the spin of any new particle is critical in identifying the true
theory among various extensions of the Standard Model (SM). The degree of
-boson polarization in any two-body decay process is sensitive to
the spin assignments of two new particles and . Considering all possible
spin-0, 1/2 and 1 combinations in a renormalizable field theory, we demonstrate
that -boson polarization can indeed play a role of a decisive and universal
analyzer in distinguishing the different spin assignments.Comment: 10 pages, 3 figures, 1 tabl
LEETECH facility as a flexible source of low energy electrons
A new versatile facility LEETECH for detector R&D, tests and calibration is
designed and constructed. It uses electrons produced by the photoinjector PHIL
at LAL, Orsay and provides a powerful tool for wide range R&D studies of
different detector concepts delivering "mono-chromatic" samples of low energy
electrons with adjustable energy and intensity. Among other innovative
instrumentation techniques, LEETECH will be used for testing various gaseous
tracking detectors and studying new Micromegas/InGrid concept which has very
promising characteristics of spatial resolution and can be a good candidate for
particle tracking and identification. In this paper the importance and expected
characteristics of such facility based on detailed simulation studies are
addressed
- âŠ