647 research outputs found
Management Options of Colonoscopic Splenic Injury
Injury to the spleen during routine colonoscopy is an extremely rare injury. Diagnosis and management of the injury has evolved with technological advances and experience gained in the management of splenic injuries sustained in trauma. Of the 37 reported cases of colonoscopic splenic injury, 12 had a history of prior surgery or a disease process suggesting the presence of adhesions. Only 6 had noted difficulty during the procedure, and 31 patients experienced pain, shock, or hemoglobin drop as the indication of splenic injury. Since 1989, 21/24 (87.5%) patients have been diagnosed initially using computed tomography or ultrasonography. Overall, only 27.8% have retained their spleens. None have experienced as long a delay as our patient, nor have any had an attempt at percutaneous control of the injury. This report presents an unusual case of a rare complication of colonoscopy and the unsuccessful use of one nonoperative technique, and reviews the experience reported in the world literature, including current day management options
A Burst-Based “Hebbian” Learning Rule at Retinogeniculate Synapses Links Retinal Waves to Activity-Dependent Refinement
Patterned spontaneous activity in the developing retina is necessary to drive synaptic refinement in the lateral geniculate nucleus (LGN). Using perforated patch recordings from neurons in LGN slices during the period of eye segregation, we examine how such burst-based activity can instruct this refinement. Retinogeniculate synapses have a novel learning rule that depends on the latencies between pre- and postsynaptic bursts on the order of one second: coincident bursts produce long-lasting synaptic enhancement, whereas non-overlapping bursts produce mild synaptic weakening. It is consistent with “Hebbian” development thought to exist at this synapse, and we demonstrate computationally that such a rule can robustly use retinal waves to drive eye segregation and retinotopic refinement. Thus, by measuring plasticity induced by natural activity patterns, synaptic learning rules can be linked directly to their larger role in instructing the patterning of neural connectivity
Willingness to test for BRCA1/2 in High Risk Women: Influenced by Risk Perception and Family Experience, rather than by Objective or Subjective Numeracy?
Genetic testing for breast and ovarian cancer can help target prevention programs, and possibly reduce morbidity and mortality. A positive result of BRCA1/2 is a substantial risk factor for breast and ovarian cancer, and its detection often leads to risk reduction interventions such as increased screening, prophylactic mastectomy and oophorectomy. We examined predictors of the decision to undergo cancer related genetic testing: perceived risk, family risk of breast or ovarian cancer, and numeracy as predictors of the decision to test among women at high risk of breast cancer. Stepwise regression analysis of survey responses from 459 women registered in the Cancer Genetics Network revealed greater likelihood to test for women with more family history, higher perceived risk of mutation, or Ashkenazi descent. Neither subjective nor objective numeracy was associated with the decision to test, although we replicated an earlier finding that subjective numeracy predicted willingness to pay for testing. Findings underscore the need for genetic counselling that disentangles risk perception from objective information to promote better decision-making in the context of genetic testing. Highlighting these factors is crucial for public health campaigns, as well as to clinic-based testing and direct-to-consumer testing. (PsycINFO Database Record (c) 2016 APA, all rights reserved
Applications of patching to quadratic forms and central simple algebras
This paper provides applications of patching to quadratic forms and central
simple algebras over function fields of curves over henselian valued fields. In
particular, we use a patching approach to reprove and generalize a recent
result of Parimala and Suresh on the u-invariant of p-adic function fields, for
p odd. The strategy relies on a local-global principle for homogeneous spaces
for rational algebraic groups, combined with local computations.Comment: 48 pages; connectivity now required in the definition of rational
group; beginning of Section 4 reorganized; other minor change
Reaping the Benefits and Avoiding the Risks: Unrealistic Optimism in the Health Domain.
People's perceptions of benefits and risks play a key role in their acceptance or rejection of medical interventions, yet these perceptions may be poorly calibrated. This online study with N = 373 adults aged 19-76 years focused on unrealistic optimism in the health domain. Participants indicated how likely they were to experience benefits and risks associated with medical conditions and completed objective and subjective numeracy scales. Participants exhibited optimistic views about the likelihood of experiencing the benefits and the side effects of treatment options described in the scenarios. Objective and subjective numeracy were not associated with more accurate ratings. Moreover, participants' underestimation of the risks was significantly greater than their overestimation of the benefits. From an applied perspective, these results suggest that clinicians may need to ensure that patients do not underestimate risks of medical interventions, and that they convey realistic expectations about the benefits that can be obtained with certain procedures
Measures on Banach Manifolds and Supersymmetric Quantum Field Theory
We show how to construct measures on Banach manifolds associated to
supersymmetric quantum field theories. These measures are mathematically
well-defined objects inspired by the formal path integrals appearing in the
physics literature on quantum field theory. We give three concrete examples of
our construction. The first example is a family of measures on a
space of functions on the two-torus, parametrized by a polynomial (the
Wess-Zumino-Landau-Ginzburg model). The second is a family \mu_\cG^{s,t} of
measures on a space \cG of maps from to a Lie group (the
Wess-Zumino-Novikov-Witten model). Finally we study a family
of measures on the product of a space of connection s on the trivial principal
bundle with structure group on a three-dimensional manifold with a
space of \fg-valued three-forms on
We show that these measures are positive, and that the measures
\mu_\cG^{s,t} are Borel probability measures. As an application we show that
formulas arising from expectations in the measures \mu_\cG^{s,1} reproduce
formulas discovered by Frenkel and Zhu in the theory of vertex operator
algebras. We conjecture that a similar computation for the measures
where is a homology three-sphere, will yield the
Casson invariant of Comment: Minor correction
Diagnosis and Management of Esophageal Injuries: A Western Trauma Association Critical Decisions Algorithm
ABSTRACT: This is a recommended management algorithm from the Western Trauma Association addressing the diagnostic evaluation and management of esophageal injuries in adult patients. Because there is a paucity of published prospective randomized clinical trials that have generated Class I data, the recommendations herein are based primarily on published observational studies and expert opinion of Western Trauma Association members. The algorithms and accompanying comments represent a safe and sensible approach that can be followed at most trauma centers. We recognize that there will be patient, personnel, institutional, and situational factors that may warrant or require deviation from the recommended algorithm. We encourage institutions to use this guideline to formulate their own local protocols.
The algorithm contains letters at decision points; the corresponding paragraphs in the text elaborate on the thought process and cite pertinent literature. The annotated algorithm is intended to (a) serve as a quick bedside reference for clinicians; (b) foster more detailed patient care protocols that will allow for prospective data collection and analysis to identify best practices; and (c) generate research projects to answer specific questions concerning decision making in the management of adults with esophageal injuries
Coordinated optimization of visual cortical maps (I) Symmetry-based analysis
In the primary visual cortex of primates and carnivores, functional
architecture can be characterized by maps of various stimulus features such as
orientation preference (OP), ocular dominance (OD), and spatial frequency. It
is a long-standing question in theoretical neuroscience whether the observed
maps should be interpreted as optima of a specific energy functional that
summarizes the design principles of cortical functional architecture. A
rigorous evaluation of this optimization hypothesis is particularly demanded by
recent evidence that the functional architecture of OP columns precisely
follows species invariant quantitative laws. Because it would be desirable to
infer the form of such an optimization principle from the biological data, the
optimization approach to explain cortical functional architecture raises the
following questions: i) What are the genuine ground states of candidate energy
functionals and how can they be calculated with precision and rigor? ii) How do
differences in candidate optimization principles impact on the predicted map
structure and conversely what can be learned about an hypothetical underlying
optimization principle from observations on map structure? iii) Is there a way
to analyze the coordinated organization of cortical maps predicted by
optimization principles in general? To answer these questions we developed a
general dynamical systems approach to the combined optimization of visual
cortical maps of OP and another scalar feature such as OD or spatial frequency
preference.Comment: 90 pages, 16 figure
- …