4,530 research outputs found
Orthogonal Range Reporting and Rectangle Stabbing for Fat Rectangles
In this paper we study two geometric data structure problems in the special
case when input objects or queries are fat rectangles. We show that in this
case a significant improvement compared to the general case can be achieved.
We describe data structures that answer two- and three-dimensional orthogonal
range reporting queries in the case when the query range is a \emph{fat}
rectangle. Our two-dimensional data structure uses words and supports
queries in time, where is the number of points in the
data structure, is the size of the universe and is the number of points
in the query range. Our three-dimensional data structure needs
words of space and answers queries in time. We also consider the rectangle stabbing problem on a set of
three-dimensional fat rectangles. Our data structure uses space and
answers stabbing queries in time.Comment: extended version of a WADS'19 pape
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
G-flux and Spectral Divisors
We propose a construction of G-flux in singular elliptic Calabi-Yau fourfold
compactifications of F-theory, which in the local limit allow a spectral cover
description. The main tool of construction is the so-called spectral divisor in
the resolved Calabi-Yau geometry, which in the local limit reduces to the Higgs
bundle spectral cover. We exemplify the workings of this in the case of an E_6
singularity by constructing the resolved geometry, the spectral divisor and in
the local limit, the spectral cover. The G-flux constructed with the spectral
divisor is shown to be equivalent to the direct construction from suitably
quantized linear combinations of holomorphic surfaces in the resolved geometry,
and in the local limit reduces to the spectral cover flux.Comment: 30 page
Lepton Jets in (Supersymmetric) Electroweak Processes
We consider some of the recent proposals in which weak-scale dark matter is
accompanied by a GeV scale dark sector that could produce spectacular
lepton-rich events at the LHC. Since much of the collider phenomenology is only
weakly model dependent it is possible to arrive at generic predictions for the
discovery potential of future experimental searches. We concentrate on the
production of dark states through bosons and electroweak-inos at the
Tevatron or LHC, which are the cleanest channels for probing the dark sector.
We properly take into account the effects of dark radiation and dark cascades
on the formation of lepton jets. Finally, we present a concrete definition of a
lepton jet and suggest several approaches for inclusive experimental searches.Comment: 23 pages, 13 figures, published version, added section 3.3 expanding
on lepton jet's morpholog
What do -ray bursts look like?
There have been great and rapid progresses in the field of -ray
bursts (denoted as GRBs) since BeppoSAX and other telescopes discovered their
afterglows in 1997. Here, we will first give a brief review on the
observational facts of GRBs and direct understanding from these facts, which
lead to the standard fireball model. The dynamical evolution of the fireball is
discussed, especially a generic model is proposed to describe the whole
dynamical evolution of GRB remnant from highly radiative to adiabatic, and from
ultra-relativistic to non-relativistic phase. Then, Various deviations from the
standard model are discussed to give new information about GRBs and their
environment. In order to relax the energy crisis, the beaming effects and their
possible observational evidences are also discussed in GRB's radiations.Comment: 10 pages, Latex. Invited talk at the Pacific Rim Conference on
Stellar Astrophysics, Hong Kong, China, Aug. 199
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
Sodium bicarbonate and high-intensity-cycling capacity: variability in responses
Purpose: The aim of this study was to determine whether gastrointestinal (GI) distress affects the ergogenicity of sodium bicarbonate and whether the degree of alkalaemia or other metabolic responses are different between individuals who improve exercise capacity and those who do not. Methods: Twenty-one males completed two cycling capacity tests at 110% of maximum power output. Participants were supplemented with 0.3 g∙kg-1BM of either placebo (maltodextrin) or sodium bicarbonate (SB). Blood pH, bicarbonate, base excess and lactate were determined at baseline, pre-exercise, immediately post-exercise and 5 minutes post-exercise. Results: SB supplementation did not significantly increase total work done (TWD) (P = 0.16, 46.8 ± 9.1 vs. 45.6 ± 8.4 kJ, d = 0.14), although magnitude based inferences suggested a 63% likelihood of a positive effect. When data were analysed without four participants who experienced GI discomfort, TWD (P = 0.01) was significantly improved with SB. Immediately post-exercise blood lactate was higher in SB for the individuals who improved but not for those who didn’t. There were also differences in the pre to post-exercise change in blood pH, bicarbonate and base excess between individuals who improved and individuals who did not. Conclusions: SB improved high intensity cycling capacity, but only with the exclusion of participants experiencing GI discomfort. Differences in blood responses suggest that sodium bicarbonate may not be beneficial to all individuals. Magnitude based inferences suggested that the exercise effects are unlikely to be negative; therefore individuals should determine whether they respond well to sodium bicarbonate supplementation prior to competition
Wavefunctions and the Point of E8 in F-theory
In F-theory GUTs interactions between fields are typically localised at
points of enhanced symmetry in the internal dimensions implying that the
coefficient of the associated operator can be studied using a local
wavefunctions overlap calculation. Some F-theory SU(5) GUT theories may exhibit
a maximum symmetry enhancement at a point to E8, and in this case all the
operators of the theory can be associated to the same point. We take initial
steps towards the study of operators in such theories. We calculate
wavefunctions and their overlaps around a general point of enhancement and
establish constraints on the local form of the fluxes. We then apply the
general results to a simple model at a point of E8 enhancement and calculate
some example operators such as Yukawa couplings and dimension-five couplings
that can lead to proton decay.Comment: 46 page
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