2,423 research outputs found
Outcomes of total hip arthroplasty, as a salvage procedure, following failed internal fixation of intracapsular fractures of the femoral neck: a systematic review and meta-analysis.
AIMS: The optimal management of intracapsular fractures of the femoral neck in independently mobile patients remains open to debate. Successful fixation obviates the limitations of arthroplasty for this group of patients. However, with fixation failure rates as high as 30%, the outcome of revision surgery to salvage total hip arthroplasty (THA) must be considered. We carried out a systematic review to compare the outcomes of salvage THA and primary THA for intracapsular fractures of the femoral neck. PATIENTS AND METHODS: We performed a Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) compliant systematic review, using the PubMed, EMBASE and Cochrane libraries databases. A meta-analysis was performed where possible, and a narrative synthesis when a meta-analysis was not possible. RESULTS: Our analyses revealed a significantly increased risk of complications including deep infection, early dislocation and peri-prosthetic fracture with salvage THA when compared with primary THA for an intracapsular fracture of the femoral neck (overall risk ratio of 3.15). Functional outcomes assessment using EuroQoL (EQ)-5D were not significantly different (p = 0.3). CONCLUSION: Salvage THA carries a significantly higher risk of complications than primary THA for intracapsular fractured neck of femur. Current literature is still lacking well designed studies to provide a full answer to the question. TAKE HOME MESSAGE: Salvage THA is associated with more complications than primary THA for intracapsular neck of femur fractures
How Do Galaxies Get Their Gas?
Not the way one might have thought. In hydrodynamic simulations of galaxy
formation, some gas follows the traditionally envisioned route, shock heating
to the halo virial temperature before cooling to the much lower temperature of
the neutral ISM. But most gas enters galaxies without ever heating close to the
virial temperature, gaining thermal energy from weak shocks and adiabatic
compression, and radiating it just as quickly. This ``cold mode'' accretion is
channeled along filaments, while the conventional, ``hot mode'' accretion is
quasi-spherical. Cold mode accretion dominates high redshift growth by a
substantial factor, while at z<1 the overall accretion rate declines and hot
mode accretion has greater relative importance. The decline of the cosmic star
formation rate at low z is driven largely by geometry, as the typical cross
section of filaments begins to exceed that of the galaxies at their
intersections.Comment: 7 pages, 1 figure. To be published in the proceedings of the
IGM/Galaxy Connection- The Distribution of Baryons at z=0 conferenc
Probing Cosmic Dawn: Modelling the Assembly History, SEDs, and Dust Content of Selected z∼9 Galaxies
The presence of spectroscopically confirmed Balmer breaks in galaxy spectral energy distributions (SEDs) at z > 9 provides one of the best probes of the assembly history of the first generations of stars in our Universe. Recent observations of the gravitationally lensed source, MACS 1149_JD1 (JD1), indicate that significant amounts of star formation likely occurred at redshifts as high as z ≃ 15. The inferred stellar mass, dust mass, and assembly history of JD1, or any other galaxy at these redshifts that exhibits a strong Balmer break, can provide a strong test of our best theoretical models from high-resolution cosmological simulations. In this work, we present the results from a cosmological radiation-hydrodynamics simulation of the region surrounding a massive Lyman-break galaxy. For two of our most massive systems, we show that dust preferentially resides in the vicinity of the young stars thereby increasing the strength of the measured Balmer break such that the simulated SEDs are consistent with the photometry of JD1 and two other z > 9 systems (GN-z10-3 and GN-z9-1) that have proposed Balmer breaks at high redshift. We find strong variations in the shape and luminosity of the SEDs of galaxies with nearly identical stellar and halo masses, indicating the importance of morphology, assembly history, and dust distribution in making inferences on the properties of individual galaxies at high redshifts. Our results stress the importance that dust may play in modulating the observable properties of galaxies, even at the extreme redshifts of z > 9
Mass-Matching in Higgsless
Modern extra-dimensional Higgsless scenarios rely on a mass-matching between
fermionic and bosonic KK resonances to evade constraints from precision
electroweak measurements. After analyzing all of the Tevatron and LEP bounds on
these so-called Cured Higgsless scenarios, we study their LHC signatures and
explore how to identify the mass-matching mechanism, the key to their
viability. We find singly and pair produced fermionic resonances show up as
clean signals with 2 or 4 leptons and 2 hard jets, while neutral and charged
bosonic resonances are visible in the dilepton and leptonic WZ channels,
respectively. A measurement of the resonance masses from these channels shows
the matching necessary to achieve . Moreover, a large single
production of KK-fermion resonances is a clear indication of compositeness of
SM quarks. Discovery reach is below 10 fb of luminosity for resonances
in the 700 GeV range.Comment: 28 pages, 18 figure
Bioavailability, Antipsoriatic Efficacy and Tolerability of a New Light Cream with Mometasone Furoate 0.1%
Mometasone furoate, a potent glucocorticoid (class III) with a favorable benefit/risk ratio, has emerged as a standard medication for the treatment of inflammatory skin disorders. The purpose of the investigation presented here was to determine the noninferiority of a topical mometasone formulation, a light cream (O/W 60/40 emulsion) with mometasone furoate 0.1% (water content of 33%) versus marketed comparators. Using the vasoconstrictor assay, a strong blanching effect of the new cream (called Mometasone cream) comparable to that of a mometasone comparator, a fatty cream with mometasone furoate 0.1%, could be demonstrated. Thus, the topical bioavailability of the active ingredient mometasone furoate (0.1%) was regarded to be similar for Mometasone cream and the mometasone comparator. Using the psoriasis plaque test, a strong antipsoriatic effect comparable to that of the mometasone comparator was found for Mometasone cream after 12 days of occlusive treatment. A nearly identical reduction in the mean infiltrate thickness and similar mean AUC values were noted with both formulations confirmed by clinical assessment data. The noninferiority of Mometasone cream to its active comparator with re-spect to the AUC of change to baseline in infiltrate thickness was demonstrated. Both medications were well tolerated. Overall, Mometasone cream and the mometasone comparator showed similar efficacy and tolerability. Mometasone cream, in addition to its high potency and good tolerability, provides the properties of a light cream, which might make this new medication particularly suitable for application on acutely inflamed and sensitive skin. Copyright (C) 2012 S. Karger AG, Base
Super-resolution far-field ghost imaging via compressive sampling
Much more image details can be resolved by improving the system's imaging
resolution and enhancing the resolution beyond the system's Rayleigh
diffraction limit is generally called super-resolution. By combining the sparse
prior property of images with the ghost imaging method, we demonstrated
experimentally that super-resolution imaging can be nonlocally achieved in the
far field even without looking at the object. Physical explanation of
super-resolution ghost imaging via compressive sampling and its potential
applications are also discussed.Comment: 4pages,4figure
Singlet Portal to the Hidden Sector
Ultraviolet physics typically induces a kinetic mixing between gauge singlets
which is marginal and hence non-decoupling in the infrared. In singlet
extensions of the minimal supersymmetric standard model, e.g. the
next-to-minimal supersymmetric standard model, this furnishes a well motivated
and distinctive portal connecting the visible sector to any hidden sector which
contains a singlet chiral superfield. In the presence of singlet kinetic
mixing, the hidden sector automatically acquires a light mass scale in the
range 0.1 - 100 GeV induced by electroweak symmetry breaking. In theories with
R-parity conservation, superparticles produced at the LHC invariably cascade
decay into hidden sector particles. Since the hidden sector singlet couples to
the visible sector via the Higgs sector, these cascades necessarily produce a
Higgs boson in an order 0.01 - 1 fraction of events. Furthermore,
supersymmetric cascades typically produce highly boosted, low-mass hidden
sector singlets decaying visibly, albeit with displacement, into the heaviest
standard model particles which are kinematically accessible. We study
experimental constraints on this broad class of theories, as well as the role
of singlet kinetic mixing in direct detection of hidden sector dark matter. We
also present related theories in which a hidden sector singlet interacts with
the visible sector through kinetic mixing with right-handed neutrinos.Comment: 12 pages, 5 figure
Radiative Electroweak Symmetry Breaking in a Little Higgs Model
We present a new Little Higgs model, motivated by the deconstruction of a
five-dimensional gauge-Higgs model. The approximate global symmetry is
, breaking to , with a gauged subgroup of
, breaking to . Radiative corrections produce an additional small vacuum misalignment,
breaking the electroweak symmetry down to . Novel features of this
model are: the only un-eaten pseudo-Goldstone boson in the effective theory is
the Higgs boson; the model contains a custodial symmetry, which ensures that
at tree-level; and the potential for the Higgs boson is generated
entirely through one-loop radiative corrections. A small negative mass-squared
in the Higgs potential is obtained by a cancellation between the contribution
of two heavy partners of the top quark, which is readily achieved over much of
the parameter space. We can then obtain both a vacuum expectation value of
GeV and a light Higgs boson mass, which is strongly correlated with the
masses of the two heavy top quark partners. For a scale of the global symmetry
breaking of TeV and using a single cutoff for the fermion loops, the
Higgs boson mass satisfies 120 GeV GeV over much of
the range of parameter space. For raised to 10 TeV, these values increase
by about 40 GeV. Effects at the ultraviolet cutoff scale may also raise the
predicted values of the Higgs boson mass, but the model still favors
GeV.Comment: 32 pages, 10 figures, JHEP style. Version accepted for publication in
JHEP. Includes additional discussion of sensitivity to UV effects and
fine-tuning, revised Fig. 9, added appendix and additional references
Diversifying Selection Underlies the Origin of Allozyme Polymorphism at the Phosphoglucose Isomerase Locus in Tigriopus californicus
The marine copepod Tigriopus californicus lives in intertidal rock pools along the Pacific coast, where it exhibits strong, temporally stable population genetic structure. Previous allozyme surveys have found high frequency private alleles among neighboring subpopulations, indicating that there is limited genetic exchange between populations. Here we evaluate the factors responsible for the diversification and maintenance of alleles at the phosphoglucose isomerase (Pgi) locus by evaluating patterns of nucleotide variation underlying previously identified allozyme polymorphism. Copepods were sampled from eleven sites throughout California and Baja California, revealing deep genetic structure among populations as well as genetic variability within populations. Evidence of recombination is limited to the sample from Pescadero and there is no support for linkage disequilibrium across the Pgi locus. Neutrality tests and codon-based models of substitution suggest the action of natural selection due to elevated non-synonymous substitutions at a small number of sites in Pgi. Two sites are identified as the charge-changing residues underlying allozyme polymorphisms in T. californicus. A reanalysis of allozyme variation at several focal populations, spanning a period of 26 years and over 200 generations, shows that Pgi alleles are maintained without notable frequency changes. Our data suggest that diversifying selection accounted for the origin of Pgi allozymes, while McDonald-Kreitman tests and the temporal stability of private allozyme alleles suggests that balancing selection may be involved in the maintenance of amino acid polymorphisms within populations
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