8,637 research outputs found
Histological insights into the pathogenesis of postâRouxâenâY hyperinsulinaemic hypoglycaemia
Background ÎČâcell hyperplasia has been implicated in the aetiology of post RouxâenâY gastric bypass hyperinsulinaemic hypoglycaemia, but the pathogenesis of this condition is still unclear. Case report We report a case of a 52âyearâold man with postâRouxâenâY gastric bypass hyperinsulinaemic hypoglycaemia who underwent distal pancreatectomy to alleviate his symptoms. Pancreatic histopathology showed chronic pancreatitis with a corresponding loss of exocrine tissue and islet retention. Amyloid deposition was found in pancreatic islets. These features are more typically associated with Type 2 diabetes. Discussion This case highlights the potential multifactorial pathogenesis of symptomatic hypoglycaemia after RouxâenâY gastric bypass. What's new? We present a case of a patient with post RouxâenâY hypoglycaemia and pancreatic histology typically associated with diabetes. We show that hyperinsulinaemic hypoglycaemia has a multifactorial aetiology.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/109602/1/dme12571.pd
Decay of Superflow Confined in Thin Torus: A Realization of Tunneling Quantum Fields
The quantum nucleation of phase slips in neutral superfluids confined in a
thin torus is investigated by means of the collective coordinate method. We
have devised, with numerical justification, a certain collective coordinate to
describe the quantum nucleation process of a phase slip. Considering the
quantum fluctuation around the local minimum of the action, we calculate the
effective mass of the phase slip. Due to the coherence of the condensate
throughout the torus, the effective mass is proportional to the circumference L
of the torus, and the decay rate has a strong exponential L-dependence.Comment: 4 pages, 2 figures, REVTe
Asymptotic Energy Dependence of Hadronic Total Cross Sections from Lattice QCD
The nonperturbative approach to soft high-energy hadron-hadron scattering,
based on the analytic continuation of Wilson-loop correlation functions from
Euclidean to Minkowskian theory, allows to investigate the asymptotic energy
dependence of hadron-hadron total cross sections in lattice QCD. In this paper
we will show, using best fits of the lattice data with proper functional forms
satisfying unitarity and other physical constraints, how indications emerge in
favor of a universal asymptotic high-energy behavior of the kind B log^2 s for
hadronic total cross sections.Comment: Revised and extended version; 29 pages, 4 figure
Dynamic Mean-Field Glass Model with Reversible Mode Coupling and Trivial Hamiltonian
Often the current mode coupling theory (MCT) of glass transitions is compared
with mean field theories. We explore this possible correspondence. After
showing a simple-minded derivation of MCT with some difficulties we give a
concise account of our toy model developed to gain more insight into MCT. We
then reduce this toy model by adiabatically eliminating rapidly varying
velocity-like variables to obtain a Fokker-Planck equation for the slowly
varying density-like variables where diffusion matrix can be singular. This
gives a room for nonergodic stationary solutions of the above equation.Comment: 9 pages, contribution to the Proceedings of the Merida Satellite
Meeting to STATPHYS21 (Merida, Mexico, July 9-14, 2001). To appear in J.
Phys. Condens. Matte
Review of Alpha-Ketoglutaric Acid (AKGA) Hydrazine and Monomethylhydrazine (MMH) Neutralizing Compound
The Johnson Space Center (JSC) White Sands Test Facility (WSTF) and NASA Engineering and Safety Center (NESC) were requested by NASA Associate Administrator for Space Operations to perform an evaluation of a proposed hydrazine/monomethylhydrazine (MMH) fuel treatment method using alpha-ketoglutaric acid (AKGA). This evaluation request was prompted by preliminary tests at the Kennedy Space Center (KSC), suggesting cost and operational benefits to NASA for the Space Shuttle Program (SSP) and other hardware decontamination and decommissioning, in addition to hydrazine and MMH waste treatment activities. This paper provides the team's position on the current KSC and New Mexico Highlands University (NMHU) efforts toward implementing the AKGA treatment technology with flight hardware, ground support equipment (GSE), hydrazine and MMH spills, and vapor control. This evaluation is current to the last data examined (approximately September 2008)
Factors in perioperative care that determine blood loss in liver surgery
AbstractObjectivesExcessive blood loss during liver surgery contributes to postoperative morbidity and mortality and the minimizing of blood loss improves outcomes. This study examines pre- and intraoperative factors contributing to blood loss and identifies areas for improvement.MethodsAll patients who underwent elective hepatic resection between June 2007 and June 2009 were identified. Detailed information on the pre- and perioperative clinical course was analysed. Univariate and multivariate analyses were used to identify factors associated with intraoperative blood loss.ResultsA total of 175 patients were studied, of whom 95 (54%) underwent resection of three or more segments. Median blood loss was 782ml. Greater blood loss occurred during major resections and prolonged surgery and was associated with an increase in postoperative complications (P= 0.026). Peak central venous pressure (CVP) of >10cm H2O was associated with increased blood loss (P= 0.01). Although no differences in case mix were identified, blood loss varied significantly among anaesthetists, as did intraoperative volumes of i.v. fluids and transfusion practices.ConclusionsThis study confirms a relationship between CVP and blood loss in hepatic resection. Intraoperative CVP values were higher than those described in other studies. There was variation in the intraoperative management of patients. Collaboration between surgical and anaesthesia teams is required to minimize blood loss and the standardization of intraoperative anaesthesia practice may improve outcomes following liver surgery
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Extending the Lee Carter Model: a Three-way Decomposition
In this paper, we focus on a Multidimensional Data Analysis approach to the Lee-Carter (LC) model of mortality trends . In particular, we extend the bilinear LC model and specify a new model based on a three-way structure, which incorporates a further component in the decomposition of the log-mortality rates. A multi-way component analysis is performed using the Tucker 3 model. The suggested methodology allows us to obtain combined estimates for the three modes: i) time, ii) agegroups and iii) different populations. From the results obtained by the Tucker 3 decomposition, we can jointly compare, in both a numerical and graphical way, the relationships among all three modes and obtain a time series component as a leading indicator of the mortality trend for a group of populations. Further, we carry out a correlation analysis of the estimated trends in order to assess the reliability of the results of the three-way decomposition. The modelâs goodness of fit is assessed using an analysis of the residuals. Finally, we discuss how the synthesised mortality index can be used to build concise projected life tables for a group of populations. An application which compares ten European countries is used to illustrate the approach and provide a deeper insight into the model and its implementation
Kinetically driven glassy transition in an exactly solvable toy model with reversible mode coupling mechanism and trivial statics
We propose a toy model with reversible mode coupling mechanism and with
trivial Hamiltonian (and hence trivial statics). The model can be analyzed
exactly without relying upon uncontrolled approximation such as the
factorization approximation employed in the current MCT. We show that the model
exhibits a kinetically driven transition from an ergodic phase to nonergodic
phase. The nonergodic state is the nonequilibrium stationary solution of the
Fokker-Planck equation for the distribution function of the modelComment: 10 pages, 1 figure, contribution to the Proceedings of the Barcelona
Workshop 'Glassy Behavior of Kinetically Constrained Models'. To appear in J.
Phys. Condens. Matte
Integrating robotics into wildlife conservation: testing improvements to predator deterrents through movement
Background Agricultural and pastoral landscapes can provide important habitat for wildlife conservation, but sharing these landscapes with wildlife can create conflict that is costly and requires managing. Livestock predation is a good example of the challenges involving coexistence with wildlife across shared landscapes. Integrating new technology into agricultural practices could help minimize human-wildlife conflict. In this study, we used concepts from the fields of robotics (i.e., automated movement and adaptiveness) and agricultural practices (i.e., managing livestock risk to predation) to explore how integration of these concepts could aid the development of more effective predator deterrents.
Methods We used a colony of captive coyotes as a model system, and simulated predation events with meat baits inside and outside of protected zones. Inside the protected zones we used a remote-controlled vehicle with a state-of-the art, commercially available predator deterrent (i.e., Foxlight) mounted on the top and used this to test three treatments: (1) light only (i.e., without movement or adaptiveness), (2) predetermined movement (i.e., with movement and without adaptiveness), and (3) adaptive movement (i.e., with both movement and adaptiveness). We measured the time it took for coyotes to eat the baits and analyzed the data with a time-to-event survival strategy.
Results Survival of baits was consistently higher inside the protected zone, and the three movement treatments incrementally increased survival time over baseline except for the light only treatment in the nonprotected zone. Incorporating predetermined movement essentially doubled the efficacy of the light only treatment both inside and outside the protected zone. Incorporating adaptive movement exponentially increased survival time both inside and outside the protected zone. Our findings provide compelling evidence that incorporating existing robotics capabilities (predetermined and adaptive movement) could greatly enhance protection of agricultural resources and aid in the development of nonlethal tools for managing wildlife. Our findings also demonstrate the importance of marrying agricultural practices (e.g., spatial management of livestock at night) with new technology to improve the efficacy of wildlife deterrents
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