3,914 research outputs found
Remote Sensing of Snow in the Solar Spectrum: Experiments in the French Alps.
Two experiments were perfonned irliApril and December 1992 in the French Alps using simultaneous relnote sensing and ground truth data. Snow grain site and soot content of samples collected in thefield were measured. The Landsat thematic mapper (TM) sensor was used because it has a good spatial resolution, a middle infrared channel which is sensitive to grain size and a thermal infraredchannel. Firstj the reflectance data were compared with the theoretical results obtained from a bidirectional reflectance model. Then, some remote sehstng-derived snow parameters wbre comparediWith the outpllt ofa snow metamorphism model (CROCUS),viz., lower elevation of the snowcover, lhe surface grl1in size and the surface temperature. A digital elevation model was used to obtain thelocal incidenc:f angles and the elevation of each snow pixel. The pixels were then grouped according to CROCUS classification (range, elevation, slope, and orientation) and the mean snow chart;cheracteristicsfor each class were .compared with the tROCUS results. The lower limit of snow and the surface grain size derived from TM data were compared favourably with the model results. Larger differences werefound for the temperature, because it varies rapidly and is very sensitive to shadowing by the snrrounding mountains and also because its remote measurement is dependent on atmospheric conditions
Traumatic Obturator Hip Dislocation with Marginal Femoral Head Fracture in a 15-Year-Old Adolescent: A High-Energy Trauma-A Case Report and a Review of the Literature.
We report the case of a 15-year-old boy brought to the emergency department after a bike accident, complaining of an isolated left hip pain. The X-rays showed an obturator hip dislocation treated by closed reduction under general anaesthesia, followed by 6 weeks of discharge. The follow-up MRI performed 6 weeks after the trauma showed an avascular femoral head necrosis, for which we performed multiple retrograde femoral head drilling, completed by the injection of autologue stem cells from the iliaq crest. One year later, the patient has no hip pain, no joint limitation, and can practice BMX at a high level again. The purpose of this report is to make the physicians aware of this rare problem that may be damaging for hip function, especially in young people
Amplitude equations for systems with long-range interactions
We derive amplitude equations for interface dynamics in pattern forming
systems with long-range interactions. The basic condition for the applicability
of the method developed here is that the bulk equations are linear and solvable
by integral transforms. We arrive at the interface equation via long-wave
asymptotics. As an example, we treat the Grinfeld instability, and we also give
a result for the Saffman-Taylor instability. It turns out that the long-range
interaction survives the long-wave limit and shows up in the final equation as
a nonlocal and nonlinear term, a feature that to our knowledge is not shared by
any other known long-wave equation. The form of this particular equation will
then allow us to draw conclusions regarding the universal dynamics of systems
in which nonlocal effects persist at the level of the amplitude description.Comment: LaTeX source, 12 pages, 4 figures, accepted for Physical Review
An E. coli-produced single-chain variable fragment (scFv) targeting hepatitis B virus surface protein potently inhibited virion secretion
Hepatitis B virus (HBV) envelopes as well as empty subviral particles carry in their lipid membranes the small (S), middle (M), and large (L) surface proteins, collectively known as hepatitis B surface antigen (HBsAg). Due to their common S domain all three proteins share a surface-exposed hydrophilic antigenic loop (AGL) with a complex disulfide bridge-dependent structure. The AGL is critical for HBV infectivity and virion secretion, and thus represents a major target for neutralizing antibodies. Previously, a human monoclonal antibody (mAb) targeting a conformational epitope in the AGL, IgG12, exhibited 1000-fold higher neutralizing activity than hepatitis B immune globulin (HBIG). Here we designed a single-chain variable fragment (scFv) homolog of IgG12, G12-scFv, which could be efficiently produced in soluble form in the cytoplasm of E. coli SHuffle cells. Independent in vitro assays verified specific binding of G12-scFv to a conformational S epitope shared with IgG12. Despite 20-fold lower affinity, G12-scFv but not an irrelevant scFv potently neutralized HBV infection of susceptible hepatoma cells (IC50=1.8nM). Strikingly, low concentrations of G12-scFv blocked virion secretion from HBV producing cells (IC50=1.25nM) without disturbing intracellular viral replication, whereas extracellular HBsAg was reduced only at >100-fold higher though still nontoxic concentration. The inhibitory effects correlated with S binding specificity and presumably also G12-scFv internalization into cells. Together these data suggest G12-scFv as a highly specific yet easily accessible novel tool for basic, diagnostic, and possibly future therapeutic applications
Computational design of high performance hybrid perovskite on silicon tandem solar cells
In this study, the optoelectronic properties of a monolithically integrated
series-connected tandem solar cell are simulated. Following the large success
of hybrid organic-inorganic perovskites, which have recently demonstrated large
efficiencies with low production costs, we examine the possibility of using the
same perovskites as absorbers in a tandem solar cell. The cell consists in a
methylammonium mixed bromide-iodide lead perovskite, CH3NH3PbI3(1-x)Br3x (0 < x
< 1), top sub-cell and a single-crystalline silicon bottom sub-cell. A Si-based
tunnel junction connects the two sub-cells. Numerical simulations are based on
a one-dimensional numerical drift-diffusion model. It is shown that a top cell
absorbing material with 20% of bromide and a thickness in the 300-400 nm range
affords current matching with the silicon bottom cell. Good interconnection
between single cells is ensured by standard n and p doping of the silicon at
5.10^19cm-3 in the tunnel junction. A maximum efficiency of 27% is predicted
for the tandem cell, exceeding the efficiencies of stand-alone silicon (17.3%)
and perovskite cells (17.9%) taken for our simulations, and more importantly,
that of the record crystalline Si cells.Comment: 17 pages, 7 figure
Combining default choices and an encounter decision aid to improve tobacco cessation in primary care patients: protocol for a cluster-randomized trial.
While quitting smoking dramatically decreases overall mortality, general practitioners (GPs) are less likely to prescribe medications for smoking cessation than other cardiovascular risk factors. Guidelines recommend providers first assess patients' "readiness" to quit, an "opt-in" strategy, but only a minority of tobacco users are ready to quit on a given day. An "opt-out" strategy offering treatment as the default choice increased quit attempts in hospital and with pregnant women, but has not been tested in primary care. We will assess the efficacy of training GPs to offer treatment as the default choice using an encounter decision aid with current smokers seen in primary care.
This is a pragmatic cluster-randomized controlled superiority trial with block randomization at the GP level in private practice in French-speaking Switzerland. GPs will be blinded to the arm allocation. The intervention is a half-day training course teaching an 'opt-out' approach to smoking cessation using an encounter decision aid (paper or electronic). GPs in the enhanced usual care group receives a brief refresher training about smoking cessation without changing their behaviour. GPs in both arms will recruit 23 patients each prior to routine primary care visits. The primary outcome is the effect of consulting a GP who received the intervention on the 7-day, point prevalence, smoking abstinence 6 months after the baseline appointment. Secondary outcomes include continuous abstinence; number of quit attempts; use of smoking cessation aids; patient-perceived involvement in discussions; and changes in GP behaviour. Patient outcomes will be collected using paper and telephone questionnaires. Assuming 15% drop-out, recruiting 46 GPs with 23 patients each will give us 80% power to detect an increase in smoking cessation from 4% (control) to 10.5% (intervention), with an alpha < 0.05.
GP visits are an opportunity to administer proven smoking cessation treatments. We hypothesize GPs offering smoking cessation treatment as the default choice using an encounter decision aid will increase the number of patients who quit. This study could significantly change our approach to smoking cessation in primary care. Default choices and the electronic decision aid are low-cost, easily diffusible interventions.
ClinicalTrials.gov Identifier: NCT04868474, First Posted May 3, 2021, Last Update Posted October 6, 2021
Decay constants of P and D-wave heavy-light mesons
We investigate decay constants of P and D-wave heavy-light mesons within the
mock-meson approach. Numerical estimates are obtained using the relativistic
quark model. We also comment on recent calculations of heavy-light
pseudo-scalar and vector decay constants.Comment: REVTeX, 22 pages, uses epsf macro, 8 postscript figures include
Heavy-Higgs Lifetime at Two Loops
The Standard-Model Higgs boson with mass decays almost
exclusively to pairs of and bosons. We calculate the dominant two-loop
corrections of to the partial widths of these decays. In
the on-mass-shell renormalization scheme, the correction factor is found to be
, where the second term is the
one-loop correction. We give full analytic results for all divergent two-loop
Feynman diagrams. A subset of finite two-loop vertex diagrams is computed to
high precision using numerical techniques. We find agreement with a previous
numerical analysis. The above correction factor is also in line with a recent
lattice calculation.Comment: 26 pages, 6 postscript figures. The complete paper including figures
is also available via WWW at
http://www.physik.tu-muenchen.de/tumphy/d/T30d/PAPERS/TUM-HEP-247-96.ps.g
Periodic points in random substitution subshifts
We study various aspects of periodic points for random substitution subshifts. In order to do so, we introduce a new property for random substitutions called the disjoint images condition. We provide a procedure for determining the property for compatible random substitutions—random substitutions for which a well-defined abelianisation exists. We find some simple necessary criteria for primitive, compatible random substitutions to admit periodic points in their subshifts. In the case that the random substitution further has disjoint images and is of constant length, we provide a stronger criterion. A method is outlined for enumerating periodic points of any specified length in a random substitution subshift
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