7,873 research outputs found
NaAlSi: a self-doped semimetallic superconductor with free electrons and covalent holes
The layered ternary sp conductor NaAlSi, possessing the iron-pnictide "111"
crystal structure, superconducts at 7 K. Using density functional methods, we
show that this compound is an intrinsic (self-doped) low-carrier-density
semimetal with a number of unusual features. Covalent Al-Si valence bands
provide the holes, and free-electron-like Al 3s bands, which propagate in the
channel between the neighboring Si layers, dip just below the Fermi level to
create the electron carriers. The Fermi level (and therefore the
superconducting carriers) lies in a narrow and sharp peak within a pseudogap in
the density of states. The small peak arises from valence bands which are
nearly of pure Si, quasi-two-dimensional, flat, and coupled to Al conduction
bands. Isostructural NaAlGe, which is not superconducting above 1.6 K, has
almost exactly the same band structure except for one missing piece of small
Fermi surface. Certain deformation potentials induced by Si and Na
displacements along the c-axis are calculated and discussed. It seems likely
that the mechanism of pairing is related to that of several other lightly doped
two-dimensional nonmagnetic semiconductors (TiNCl, ZrNCl, HfNCl), which is not
well understood but apparently not of phonon origin.Comment: 9 pages, 7 figures, 1 tabl
Transcription of 2013 \u3cem\u3eChapman Law Review\u3c/em\u3e Symposium: The Future of Law, Business, and Legal Education: How to Prepare Students to Meet Corporate Needs
Reduced Fine-Tuning in Supersymmetry with R-parity violation
Both electroweak precision measurements and simple supersymmetric extensions
of the standard model prefer a mass of the Higgs boson less than the
experimental lower limit of 114 GeV. We show that supersymmetric models with R
parity violation and baryon number violation have a significant range of
parameter space in which the Higgs dominantly decays to six jets. These decays
are much more weakly constrained by current LEP analyses and would allow for a
Higgs mass near that of the . In general, lighter scalar quark and other
superpartner masses are allowed and the fine-tuning typically required to
generate the measured scale of electroweak symmetry breaking is ameliorated.
The Higgs would potentially be discovered at hadron colliders via the
appearance of new displaced vertices. The lightest neutralino could be
discovered by a scan of vertex-less events LEP I data.Comment: 5 pages, 2 figures. Significant detail added to the arguments
regarding LEP limits - made more quantitative. Better figures used, plotting
more physical quantities. Typos corrected and references updated. Conclusions
unchange
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Long-term safety of siltuximab in patients with idiopathic multicentric Castleman disease: a prespecified, open-label, extension analysis of two trials.
BACKGROUND:Siltuximab is recommended by international consensus as a first-line treatment for idiopathic multicentric Castleman disease on the basis of durable efficacy and safety data. This study was done to assess the long-term safety and activity of siltuximab over up to 6 years of treatment. METHODS:This study is a prespecified open-label extension analysis of a phase 1 trial (NCT00412321) and a phase 2 trial (NCT01024036), done at 26 hospitals worldwide. Patients in both studies were at least 18 years old with histologically confirmed, symptomatic Castleman disease. This extension study enrolled 60 patients who completed the previous trials without disease progression on siltuximab. Patients received siltuximab infusions of 11 mg/kg every 3 weeks (which could be extended to 6 weeks) for up to 6 years. Descriptive statistics were used to summarise the data. No formal hypothesis testing was performed. The primary endpoint was the safety of siltuximab, assessed at each dosing cycle. The study was registered with ClinicalTrials.gov, number NCT01400503 and with EudraCT, number 2010-022837-27. FINDINGS:Patient enrolment into the phase 1 trial was from June 20, 2005, to Sept 15, 2009, and enrolment into the phase 2 trial was from Feb 9, 2010, to Feb 3, 2012. Patients were enrolled in this long-term extension from April 1, 2011, to Jan 15, 2014. Median follow-up was 6 years (IQR 5·11-7·76). Median treatment duration, from the beginning of the previous trials to the end of the present study, was 5·5 years (IQR 4·26-7·14). Siltuximab was well tolerated; however, adverse events of grade 3 or worse were reported in 36 (60%) of 60 patients with the most common being hypertension (eight [13%]), fatigue (five [8%]), nausea (four [7%]), neutropenia (four [7%]), and vomiting (three [5%]). 25 (42%) patients reported at least one serious adverse event, which most commonly was an infection (eight [13%]). Only two serious adverse events, polycythaemia and urinary retention, were considered related to siltuximab treatment. 18 patients discontinued before study completion, either to receive siltuximab locally (eight) or because of progressive disease (two), adverse events (two), or other reasons (six). No deaths were reported. INTERPRETATION:These results show that siltuximab is well tolerated long term and provides important evidence for the feasibility of the life-long use required by patients with idiopathic multicentric Castleman disease. FUNDING:Janssen R&D and EUSA Pharma
Warm dust in the terrestrial planet zone of a sun-like Pleiad: collisions between planetary embryos?
Only a few solar-type main sequence stars are known to be orbited by warm
dust particles; the most extreme is the G0 field star BD+20 307 that emits ~4%
of its energy at mid-infrared wavelengths. We report the identification of a
similarly dusty star HD 23514, an F6-type member of the Pleiades cluster. A
strong mid-IR silicate emission feature indicates the presence of small warm
dust particles, but with the primary flux density peak at the non-standard
wavelength of ~9 micron. The existence of so much dust within an AU or so of
these stars is not easily accounted for given the very brief lifetime in orbit
of small particles. The apparent absence of very hot (>~1000 K) dust at both
stars suggests the possible presence of a planet closer to the stars than the
dust. The observed frequency of the BD+20 307/HD 23514 phenomenon indicates
that the mass equivalent of Earth's Moon must be converted, via collisions of
massive bodies, to tiny dust particles that find their way to the terrestrial
planet zone during the first few hundred million years of the life of many
(most?) sun-like stars. Identification of these two dusty systems among
youthful nearby solar-type stars suggests that terrestrial planet formation is
common.Comment: ApJ in press, 19 pages including 3 figures and 2 tables, minor
changes to the tables and figure
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Role of appetitive phenotype trajectory groups on child body weight during a family-based treatment for children with overweight or obesity.
ObjectiveEmerging evidence suggests that individual appetitive traits may usefully explain patterns of weight loss in behavioral weight loss treatments for children. The objective of this study was to identify trajectories of child appetitive traits and the impact on child weight changes over time.MethodsSecondary data analyses of a randomized noninferiority trial conducted between 2011 and 2015 evaluated children's appetitive traits and weight loss. Children with overweight and obesity (mean age = 10.4; mean BMI z = 2.0; 67% girls; 32% Hispanic) and their parent (mean age = 42.9; mean BMI = 31.9; 87% women; 31% Hispanic) participated in weight loss programs and completed assessments at baseline, 3, 6,12, and 24 months. Repeated assessments of child appetitive traits, including satiety responsiveness, food responsiveness and emotional eating, were used to identify parsimonious grouping of change trajectories. Linear mixed-effects models were used to identify the impact of group trajectory on child BMIz change over time.ResultsOne hundred fifty children and their parent enrolled in the study. The three-group trajectory model was the most parsimonious and included a high satiety responsive group (HighSR; 47.4%), a high food responsive group (HighFR; 34.6%), and a high emotional eating group (HighEE; 18.0%). Children in all trajectories lost weight at approximately the same rate during treatment, however, only the HighSR group maintained their weight loss during follow-ups, while the HighFR and HighEE groups regained weight (adjusted p-value < 0.05).ConclusionsDistinct trajectories of child appetitive traits were associated with differential weight loss maintenance. Identified high-risk subgroups may suggest opportunities for targeted intervention and maintenance programs
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