4,395 research outputs found
MRI and clinical resolution of a suspected intracranial toxoplasma granuloma with medical treatment in a domestic short hair cat
A two-year-old cat was presented with a left paradoxical vestibular syndrome. MRI of the brain revealed an extra-axial homogenously contrast enhancing mass in the region of the left caudal cerebellar peduncle. Toxoplasma serology was consistent with active infection and the lesion was suspected to be a toxoplasma granuloma. Following eight weeks of tapering oral prednisolone and 11 weeks of oral clindamycin treatment, repeat MRI revealed resolution of the lesion. Eighteen months after initial diagnosis, the cat remained neurologically normal. Differential diagnoses for a solitary, extra-axial, contrast enhancing mass lesion in the feline brain should include toxoplasma granuloma, which can undergo MRI and clinical resolution with medical treatment
Determining the Mass of Dark Matter Particles with Direct Detection Experiments
In this article I review two data analysis methods for determining the mass
(and eventually the spin-independent cross section on nucleons) of Weakly
Interacting Massive Particles with positive signals from direct Dark Matter
detection experiments: a maximum likelihood analysis with only one experiment
and a model-independent method requiring at least two experiments.
Uncertainties and caveats of these methods will also be discussed.Comment: 24 pages, 10 figures, 1 reference added, typos fixed, published
version, to appear in the NJP Focus Issue on "Dark Matter and Particle
Physics
SUSY darkmatter at the LHC - 7 TeV
We have analysed the early LHC signatures of the minimal supergravity
(mSUGRA) model. Our emphasis is on the 7 - run corresponding to an
integrated luminosity of although we have also discussed
briefly the prospects at LHC-10 . We focus on the parameter space yielding
relatively light squark and gluinos consistent with the darkmatter relic
density data and the LEP bounds on the lightest Higgs scalar mass. This
parameter space is only allowed for non-vanishing trilinear soft breaking term
. A significant region of the parameter space with large to moderate
negative values of consistent with the stability of the scalar potential
and relic density production via neutralino annihilation and/or neutralino -
stau coannihilation yields observable signal via the jets + missing transverse
energy channel. The one lepton + jets + missing energy signal is also viable
over a smaller but non-trivial parameter space. The ratio of the size of the
two signals - free from theoretical uncertainties - may distinguish between
different relic density generating mechanisms. With efficient -tagging
facilities at 7 the discriminating power may increase significantly. We
also comment on other dark matter relic density allowed mSUGRA scenarios and
variants there of in the context of LHC-7 .Comment: Brief comments on signals at 7 TeV in the Higgs funnel region of
mSUGRA, models with non universal scalar and gaugino masses have been added.
Accepted for publication in PR
Electroweak Contributions to Squark Pair Production at the LHC
In this paper we compute electroweak contributions to the production of
squark pairs at hadron colliders. These include the exchange of electroweak
gauge bosons in the s-channel as well as electroweak gaugino exchange in the t-
and/or u-channel. In many cases these can interfere with the dominant QCD
contributions. As a result, we find sizable contributions to the production of
two SU(2) doublet squarks. At the LHC, they amount to 10 to 20% for typical
mSUGRA (or CMSSM) scenarios, but in more general scenarios they can vary
between -40 and +55%, depending on size and sign of the SU(2) gaugino mass. The
electroweak contribution to the total squark pair production rate at the LHC is
about 3.5 times smaller.Comment: 28 pages, 9 figure
Inference on the tail process with application to financial time series modelling
To draw inference on serial extremal dependence within heavy-tailed Markov
chains, Drees, Segers and Warcho{\l} [Extremes (2015) 18, 369--402] proposed
nonparametric estimators of the spectral tail process. The methodology can be
extended to the more general setting of a stationary, regularly varying time
series. The large-sample distribution of the estimators is derived via
empirical process theory for cluster functionals. The finite-sample performance
of these estimators is evaluated via Monte Carlo simulations. Moreover, two
different bootstrap schemes are employed which yield confidence intervals for
the pre-asymptotic spectral tail process: the stationary bootstrap and the
multiplier block bootstrap. The estimators are applied to stock price data to
study the persistence of positive and negative shocks.Comment: 22 page
Processes at High Energy pp Colliders
In this note we investigate the production of charged heavy particles via
\gaga\ fusion at high energy pp colliders. We revise previous claims that the
\gaga\ cross section is comparable to or larger than that for the corresponding
Drell-Yan process at high energies. Indeed we find that the \gaga\ contribution
to the total production cross section at pp is far below the Drell-Yan cross
section. As far as the individual elastic, semi-elastic and inelastic
contributions to the \gaga\ process are concerned we find that they are all of
the same order of magnitude.Comment: REVTEX, 12 pages, two uuencoded figures appended at the end of the
fil
First observations of beam losses due to bound-free pair production in a heavy-ion collider
We report the first observations of beam losses due to bound-free pair
production at the interaction point of a heavy-ion collider. This process is
expected to be a major luminosity limit for the Large Hadron Collider (LHC)
when it operates with 208Pb82+ ions because the localized energy deposition by
the lost ions may quench superconducting magnet coils. Measurements were
performed at the Relativistic Heavy Ion Collider (RHIC) during operation with
100 GeV/nucleon 63Cu29+ ions. At RHIC, the rate, energy and magnetic field are
low enough so that magnet quenching is not an issue. The hadronic showers
produced when the single-electron ions struck the RHIC beampipe were observed
using an array of photodiodes. The measurement confirms the order of magnitude
of the theoretical cross section previously calculated by others.Comment: 4 pages, 5 figures. Added journal ref. Corrected typos. Fixed fig 1.
Minor improvements to fig. 1,3,4. Rephrased a small number of sentences
(p1,3,4). Added numerical values of the aperture and the displacement for Au
(p 2). Changed reference 5, added name in acknowledgments (p 4
Survey of surgical specialists’ content preferences in radiology reports for extrahepatic portosystemic shunts
The aim of this prospective, survey study was to assess the opinions of specialist surgeons as to the preferred content, nomenclature, and classification of extrahepatic portosystemic shunts for inclusion in radiology reports. A link to an online survey was sent by email to members of the European College of Veterinary Surgeons and the Association of Veterinary Soft Tissue Surgeons, and was made available on the American College of Veterinary Surgeons web forum and Facebook page. There were 93 respondents (survey sent to over 2500 email addresses and made available in two online locations). Most respondents agreed that they both review the images themselves (87/92, 95%) and read the radiology report (82/92, 89%) prior to surgery. Most respondents believed that the radiology report should contain a detailed anatomic description of the insertion (83/92, 90%), origin (54/91, 59%), and course (70/92, 76%) of the shunt, as well as a measure of the diameter of the shunting vessel at its insertion (54/92, 59%). Most respondents (70/90, 78%) disagreed that a brief description of shunt type, such as portocaval or portophrenic, was sufficient. Respondents were undecided regarding the use of an alphanumeric classification system (36/92, 39% agree; 32/92, 35% disagree). There was agreement that details of the presence or absence of urolithiasis (91/93, 98%), renomegaly (54/93, 58%), and peritoneal fluid (72/92, 78%) should be included in the report. The results of this study will help to guide reporting radiologists in providing descriptions of extrahepatic portosystemic shunts that include information most preferred by the recipient surgeons
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