757 research outputs found
Radii in the shell and the "halo" orbit: A game changer
Proton radii of nuclei in the shell depart appreciably from the
asymptotic law, . The departure exhibits systematic
trends fairly well described by a single phenomenological term in the
Duflo-Zuker formulation, which also happens to explain the sudden increase in
slope in the isotope shifts of several chains at neutron number . It was
recently shown that this term is associated with the abnormally large size of
the and orbits in the and shells respectively. Further
to explore the problem, we propose to calculate microscopically radii in the
former. Since the (square) radius is basically a one body operator, its
evolution is dictated by single particle occupancies determined by shell model
calculations. Assuming that the departure from the asymptotic form is entirely
due to the orbit, the expectation value is determined by demanding that its evolution be
such as to describe well nuclear radii. It does, for an orbit that remains very
large (about 1.6 fm bigger than its counterparts) up to then
drops abruptly but remains some 0.6 fm larger than the orbits. An
unexpected behavior bound to challenge our understanding of shell formation.Comment: 4 pages 6(7) figure
Neutron Skins and Halo Orbits in the sd and pf Shells
open3siThe strong dependence of Coulomb energies on nuclear radii makes it possible to extract the latter from
calculations of the former. The resulting estimates of neutron skins indicate that two mechanisms are
involved. The first one --isovector monopole polarizability—amounts to noting that when a particle is
added to a system it drives the radii of neutrons and protons in different directions, tending to equalize the
radii of both fluids independently of the neutron excess. This mechanism is well understood and the Duflo-
Zuker (small) neutron skin values derived 14 years ago are consistent with recent measures and estimates.
The alternative mechanism involves halo orbits whose huge sizes tend to make the neutron skins larger and
have a subtle influence on the radial behavior of sd and f shell nuclei. In particular, they account for the
sudden rise in the isotope shifts of nuclei beyond N=28 and the near constancy of radii in the A=40–56
region. This mechanism, detected here for the first time, is not well understood and may well go beyond the
Efimov physics usually associated with halo orbits.openBonnard, JEREMY CHRISTIAN FREDERIC; Lenzi, SILVIA MONICA; Zuker, A. P.Bonnard, JEREMY CHRISTIAN FREDERIC; Lenzi, SILVIA MONICA; Zuker, A. P
General unifying features of controlled quantum phenomena
Many proposals have been put forth for controlling quantum phenomena,
including open-loop, adaptive feedback, and real-time feedback control. Each of
these approaches has been viewed as operationally, and even physically,
distinct from the others. This work shows that all such scenarios inherently
share the same fundamental control features residing in the topology of the
landscape relating the target physical observable to the applied controls. This
unified foundation may provide a basis for development of hybrid control
schemes that would combine the advantages of the existing approaches to achieve
the best overall performance.Comment: The published version (includes the supplementary material
Association between serum cytokine profiles and schistosomiasis-related hepatic fibrosis: Infection by Schistosoma japonicum versus S-mansoni
Outcome of alimentary tract duplications operated on by minimally invasive surgery: a retrospective multicenter study by the GECI (Groupe d'Etude en Coeliochirurgie Infantile).
BACKGROUND: Alimentary tract duplications (ATD) are a rare cause of intestinal obstruction in childhood. There are many case reports but few series about laparoscopy or thoracoscopy for ATD. The aim of our study was to report the outcome of minimally invasive surgery (MIS) for ATD.
METHODS: This was a retrospective multicenter study from the GECI (Groupe d\u27Etude en Coeliochirurgie Infantile). We reviewed the charts of 114 patients operated on by MIS for ATD from 1994 to 2009.
RESULTS: Sixty-two patients (54 %) had a prenatal diagnosis. Forty-nine patients (43 %) were symptomatic before surgery: 33 of those patients (63 %) with postnatal diagnosis compared to 16 (25 %) with prenatal diagnosis (P < 0.01). In this last group, the median age at onset of symptoms was 16 days (range = 0-972). One hundred and two patients had laparoscopy (esophageal to rectal duplications) and 12 patients had thoracoscopy for esophageal duplications. The mean operative time was 90 min (range = 82-98). There were 32 (28 %) resection anastomoses, 55 (48 %) enucleations, and 27 (24 %) unroofings. The conversion rate was 32 %, and in a multivariate analysis, it was significantly higher, up to 41 % for patients weighing <10 kg (P < 0.01). Ten patients (8 %) had unintentional perioperative opening of the digestive tract during the dissection. Eight patients had nine postoperative complications, including six small bowel obstructions. The median length of hospital stay was 4 days (range = 1-21) without conversion and 6 days (range = 1-27) with conversion (P = 0.01). The median follow-up was 3 months (range = 1-120). Eighteen of the 27 patients who underwent partial surgery had an ultrasound examination during follow-up. Five (18 %) of them had macroscopic residue.
CONCLUSION: This study showed that MIS for ATD is feasible with a low rate of complications. Patients with prenatal diagnosis should have prompt surgery to prevent symptoms, despite a high rate of conversion in small infants
Infrastructure for Detector Research and Development towards the International Linear Collider
The EUDET-project was launched to create an infrastructure for developing and
testing new and advanced detector technologies to be used at a future linear
collider. The aim was to make possible experimentation and analysis of data for
institutes, which otherwise could not be realized due to lack of resources. The
infrastructure comprised an analysis and software network, and instrumentation
infrastructures for tracking detectors as well as for calorimetry.Comment: 54 pages, 48 picture
De novo mutations in SMCHD1 cause Bosma arhinia microphthalmia syndrome and abrogate nasal development
Bosma arhinia microphthalmia syndrome (BAMS) is an extremely rare and striking condition characterized by complete absence of the nose with or without ocular defects. We report here that missense mutations in the epigenetic regulator SMCHD1 mapping to the extended ATPase domain of the encoded protein cause BAMS in all 14 cases studied. All mutations were de novo where parental DNA was available. Biochemical tests and in vivo assays in Xenopus laevis embryos suggest that these mutations may behave as gain-of-function alleles. This finding is in contrast to the loss-of-function mutations in SMCHD1 that have been associated with facioscapulohumeral muscular dystrophy (FSHD) type 2. Our results establish SMCHD1 as a key player in nasal development and provide biochemical insight into its enzymatic function that may be exploited for development of therapeutics for FSHD
Esophageal atresia: data from a national cohort
PURPOSE: A prospective national register was established in 2008 to record all new cases of live-birth newborns with esophageal atresia (EA). This epidemiological survey was recommended as part of a national rare diseases plan.
METHODS: All 38 national centers treating EA participated by completing for each patient at first discharge a questionnaire validated by a national committee of experts. Data were centralized by the national reference center for esophageal anomalies. Quantitative and qualitative analyses were performed, with P-values of less than 0.05 considered statistically significant. Results of the 2008-2009 data collection are presented in this report.
RESULTS: Three hundred seven new living cases of EA were recorded between January 1, 2008, and December 31, 2009. The male/female sex ratio was 1.3, and the live-birth prevalence of EA was 1.8 per 10,000 births. Major characteristics were comparable to those reported in the literature. Survival was 95%, and no correlation with caseload was noted.
CONCLUSIONS: Epidemiologic surveys of congenital anomalies such as EA, which is a rare disease, provide valuable data for public health authorities and fulfill one important mission of reference centers. When compared with previous epidemiological data, this national population-based registry suggests that the incidence of EA remains stable
Le diagnostic anténatal modifie-t-il la prise en charge néonatale et le devenir à 1 an des enfants suivis pour atrésie de l’œsophage de type III ?
OBJECTIVE:
Evaluate neonatal management and outcome of neonates with either a prenatal or a post-natal diagnosis of EA type III.
STUDY DESIGN:
Population-based study using data from the French National Register for EA from 2008 to 2010. We compared children with prenatal versus post-natal diagnosis in regards to prenatal, maternal and neonatal characteristics. We define a composite variable of morbidity (anastomotic esophageal leaks, recurrent fistula, stenosis) and mortality at 1 year.
RESULTS:
Four hundred and eight live births with EA type III were recorded with a prenatal diagnosis rate of 18.1%. Transfer after birth was lower in prenatal subset (32.4% versus 81.5%, P<0.001). Delay between birth and first intervention was not significantly different. Defect size (2cm vs 1.4cm, P<0.001), gastrostomy (21.6% versus 8.7%, P<0.001) and length in neonatal unit care were higher in prenatal subset (47.9 days versus 33.6 days, P<0.001). The composite variables were higher in prenatal diagnosis subset (38.7% vs 26.1%, P=0.044).
CONCLUSION:
Despite the excellent survival rate of EA, cases with antenatal detection have a higher morbidity related to the EA type (longer gap). Even if it does not modify neonatal management and 1-year outcome, prenatal diagnosis allows antenatal parental counseling and avoids post-natal transfer
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