698 research outputs found
Hip joint replacement surgery for idiopathic osteoarthritis aggregates in families
In order to determine whether there is a genetic component to hip or knee joint failure due to idiopathic osteoarthritis (OA), we invited patients (probands) undergoing hip or knee arthroplasty for management of idiopathic OA to provide detailed family histories regarding the prevalence of idiopathic OA requiring joint replacement in their siblings. We also invited their spouses to provide detailed family histories about their siblings to serve as a control group. In the probands, we confirmed the diagnosis of idiopathic OA using American College of Rheumatology criteria. The cohorts included the siblings of 635 probands undergoing total hip replacement, the siblings of 486 probands undergoing total knee replacement, and the siblings of 787 spouses. We compared the prevalence of arthroplasty for idiopathic OA among the siblings of the probands with that among the siblings of the spouses, and we used logistic regression to identify independent risk factors for hip and knee arthroplasty in the siblings. Familial aggregation for hip arthroplasty, but not for knee arthroplasty, was observed after controlling for age and sex, suggesting a genetic contribution to end-stage hip OA but not to end-stage knee OA. We conclude that attempts to identify genes that predispose to idiopathic OA resulting in joint failure are more likely to be successful in patients with hip OA than in those with knee OA
Casting Light on Dark Matter
The prospects for detecting a candidate supersymmetric dark matter particle
at the LHC are reviewed, and compared with the prospects for direct and
indirect searches for astrophysical dark matter. The discussion is based on a
frequentist analysis of the preferred regions of the Minimal supersymmetric
extension of the Standard Model with universal soft supersymmetry breaking (the
CMSSM). LHC searches may have good chances to observe supersymmetry in the near
future - and so may direct searches for astrophysical dark matter particles,
whereas indirect searches may require greater sensitivity, at least within the
CMSSM.Comment: 16 pages, 13 figures, contribution to the proceedings of the LEAP
2011 Conferenc
Lateral rectus metastasis from an occult systemic malignancy masquerading as abducens palsy: a case report
<p>Abstract</p> <p>Introduction</p> <p>Abduction deficit in the elderly is commonly caused by sixth cranial nerve palsy due to microvasculopathy. However, not all such cases are of neurogenic origin, as our case report shows.</p> <p>Case presentation</p> <p>We present the case of a 75-year-old woman who was generally unwell, developed acute diplopia and was found to have a right abduction deficit in a quiet eye with no gross orbital signs and symptoms. A computed tomography scan of the head and orbits revealed a metastatic mass in the right lateral rectus muscle. Systemic evaluation confirmed widespread thoracic and abdominal metastases from an occult systemic malignancy. Lateral rectus metastasis from an occult systemic malignancy was masquerading as abducens palsy.</p> <p>Conclusion</p> <p>Orbital metastasis involving extraocular muscles can present as isolated diplopia with minimal local signs and the absence of a history of systemic malignancy. A detailed history and systemic examination can identify suspicious cases, which should be investigated further. The clinician should avoid presuming that such an abduction deficit in the elderly is a benign neurogenic palsy.</p
Four Generations: SUSY and SUSY Breaking
We revisit four generations within the context of supersymmetry. We compute
the perturbativity limits for the fourth generation Yukawa couplings and show
that if the masses of the fourth generation lie within reasonable limits of
their present experimental lower bounds, it is possible to have perturbativity
only up to scales around 1000 TeV. Such low scales are ideally suited to
incorporate gauge mediated supersymmetry breaking, where the mediation scale
can be as low as 10-20 TeV. The minimal messenger model, however, is highly
constrained. While lack of electroweak symmetry breaking rules out a large part
of the parameter space, a small region exists, where the fourth generation stau
is tachyonic. General gauge mediation with its broader set of boundary
conditions is better suited to accommodate the fourth generation.Comment: 27 pages, 5 figure
How Can Home Care Patients and Their Caregivers Better Manage Fall Risks by Leveraging Information Technology?
Objectives: From the perspectives of home care patients and caregivers, this study aimed to (a) identify the challenges for better fall-risk management during home care episodes and (b) explore the opportunities for them to leverage health information technology (IT) solutions to improve fall-risk management during home care episodes. Methods: Twelve in-depth semistructured interviews with the patients and caregivers were conducted within a descriptive single case study design in 1 home health agency (HHA) in the mid-Atlantic region of the United States. Results: Patients and caregivers faced challenges to manage fall risks such as unmanaged expectations, deteriorating cognitive abilities, and poor care coordination between the HHA and physician practices. Opportunities to leverage health IT solutions included patient portals, telehealth, and medication reminder apps on smartphones. Conclusion: Effectively leveraging health IT could further empower patients and caregivers to reduce fall risks by acquiring the necessary information and following clinical advice and recommendations. The HHAs could improve the quality of care by adopting IT solutions that show more promise of improving the experiences of patients and caregivers in fall-risk management
Stable isotopes and mtDNA reveal niche segregation but no evidence of intergradation along a habitat gradient in the Lesser Whitethroat complex (Sylvia curruca; Passeriformes; Aves)
Niche segregation plays a critical role in the speciation process, but determining the extent to which taxa are geographically or ecologically isolated is challenging. In this study, we use stable isotopes of carbon (δ13C), nitrogen (δ15N), hydrogen (δ2H) and oxygen (δ18O) to test for ecological differences among taxa in the Lesser Whitethroat Sylvia curruca complex. Analysis of mitochondrial DNA (mtDNA) revealed 6 distinct haplotype groups, which conform to at least 5 distinct taxa. Stable isotopes provided insight into geographical and broad-scale ecological differences among haplotypes. The most striking isotope differences were between the populations inhabiting Siberian boreal forest (S. c. blythi) from the one inhabiting semi-desert in Kazakhstan (S. c. halimodendri). It is generally assumed that these two populations form a morphological cline along a gradient from mesic to xeric habitat. Our sample includes a large proportion of morphologically intermediate individuals that appear to represent a hybrid population. However, in all of these, there is strict correspondence between haplotype and isotope signature, suggesting an ecological division on the breeding grounds between all our samples of these two taxa. The lack of ecologically intermediate individuals among our sample of morphologically intermediate ones thus speaks against the existence of a cline. The two taxa blythi and halimodendri emerge as potential models for the study of the early stages of the speciation process. While differences in stable isotopes may be largely influenced by geography, we also demonstrate how, in specific instances (such as the alleged cline reported here), they may be used to evaluate niche segregation between taxa, providing information of importance for determination of species limits
R-parity Conservation via the Stueckelberg Mechanism: LHC and Dark Matter Signals
We investigate the connection between the conservation of R-parity in
supersymmetry and the Stueckelberg mechanism for the mass generation of the B-L
vector gauge boson. It is shown that with universal boundary conditions for
soft terms of sfermions in each family at the high scale and with the
Stueckelberg mechanism for generating mass for the B-L gauge boson present in
the theory, electric charge conservation guarantees the conservation of
R-parity in the minimal B-L extended supersymmetric standard model. We also
discuss non-minimal extensions. This includes extensions where the gauge
symmetries arise with an additional U(1)_{B-L} x U(1)_X, where U(1)_X is a
hidden sector gauge group. In this case the presence of the additional U(1)_X
allows for a Z' gauge boson mass with B-L interactions to lie in the sub-TeV
region overcoming the multi-TeV LEP constraints. The possible tests of the
models at colliders and in dark matter experiments are analyzed including
signals of a low mass Z' resonance and the production of spin zero bosons and
their decays into two photons. In this model two types of dark matter
candidates emerge which are Majorana and Dirac particles. Predictions are made
for a possible simultaneous observation of new physics events in dark matter
experiments and at the LHC.Comment: 38 pages, 7 fig
Is chronic pelvic pain a comfortable diagnosis for primary care practitioners: a qualitative study
<p>Abstract</p> <p>Background</p> <p>Chronic pelvic pain (CPP) has a prevalence similar to asthma and chronic back pain, but little is known about how general practitioners (GPs) and practice nurses manage women with this problem. A clearer understanding of current management is necessary to develop appropriate strategies, in keeping with current health care policy, for the supported self-management of patients with long term conditions. The aim of this study was to explore GPs' and practice nurses' understanding and perspectives on the management of chronic pelvic pain.</p> <p>Methods</p> <p>Data were collected using semi-structured interviews with a purposive sample of 21 GPs and 20 practice nurses, in three primary care trusts in the North West of England. Data were analysed using the principles of Framework analysis.</p> <p>Results</p> <p>Analysis suggests that women who present with CPP pose a challenge to GPs and practice nurses. CPP is not necessarily recognized as a diagnostic label and making the diagnosis was achieved only by exclusion. This contrasts with the relative acceptability of labels such as irritable bowel syndrome (IBS). GPs expressed elements of therapeutic nihilism about the condition. Despite practice nurses taking on increasing responsibilities for the management of patients with long term conditions, respondents did not feel that CPP was an area that they were comfortable in managing.</p> <p>Conclusions</p> <p>The study demonstrates an educational/training need for both GPs and practice nurses. GPs described a number of skills and clinical competencies which could be harnessed to develop a more targeted management strategy. There is potential to develop facilitated self- management for use in this patient group, given that this approach has been successful in patients with similar conditions such as IBS.</p
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