1,493 research outputs found
Identification of proteins in the postsynaptic density fraction by mass spectrometry
Our understanding of the organization of postsynaptic signaling systems at excitatory synapses has been aided by the identification of proteins in the postsynaptic density (PSD) fraction, a subcellular fraction enriched in structures with the morphology of PSDs. In this study, we have completed the identification of most major proteins in the PSD fraction with the use of an analytical method based on mass spectrometry coupled with searching of the protein sequence databases. At least one protein in each of 26 prominent protein bands from the PSD fraction has now been identified. We found 7 proteins not previously known to be constituents of the PSD fraction and 24 that had previously been associated with the PSD by other methods. The newly identified proteins include the heavy chain of myosin-Va (dilute myosin), a motor protein thought to be involved in vesicle trafficking, and the mammalian homolog of the yeast septin protein cdc10, which is important for bud formation in yeast. Both myosin-Va and cdc10 are threefold to fivefold enriched in the PSD fraction over brain homogenates. Immunocytochemical localization of myosin-Va in cultured hippocampal neurons shows that it partially colocalizes with PSD-95 at synapses and is also diffusely localized in cell bodies, dendrites, and axons. Cdc10 has a punctate distribution in cell bodies and dendrites, with some of the puncta colocalizing with PSD-95. The results support a role for myosin-Va in transport of materials into spines and for septins in the formation or maintenance of spines
Risk Aversion among Smallholder High-value Crop Farmers in the Southern Philippines
Several elicitation techniques were employed to gauge the attitudes to risk of smallholder high-value crop farmers in the southern Philippines. Results showed varying degrees of risk aversion, neutrality, and preference among smallholder farmers. Although some of the techniques classified distinct groups of local growers as either risk-averse or risk-preferring, the estimated risk aversion coefficients were relatively low signifying an inclination toward risk neutrality. These may partly explain the degree of openness or non-openness of smallholder farmers to cultural changes and development interventions. Variations in farmers' risk attitude classification among the different elicitation methods indicate the need for further validation studies and more definitive evaluation standards
Compact Hyperbolic Extra Dimensions: Branes, Kaluza-Klein Modes and Cosmology
We reconsider theories with low gravitational (or string) scale M_* where
Newton's constant is generated via new large-volume spatial dimensions, while
Standard Model states are localized to a 3-brane. Utilizing compact hyperbolic
manifolds (CHM's) we show that the spectrum of Kaluza-Klein (KK) modes is
radically altered. This allows an early universe cosmology with normal
evolution up to substantial temperatures, and completely negates the
constraints on M_* arising from astrophysics. Furthermore, an exponential
hierarchy between the usual Planck scale and the true fundamental scale of
physics can emerge with only order unity coefficients. The linear size of the
internal space remains small. The proposal has striking testable signatures.Comment: 4 pages, no figure
Advances in Measuring the Apparent Optical Properties (AOPs) of Optically Complex Waters
This report documents new technology used to measure the apparent optical properties (AOPs) of optically complex waters. The principal objective is to be prepared for the launch of next-generation ocean color satellites with the most capable commercial off-the-shelf (COTS) instrumentation. An enhanced COTS radiometer was the starting point for designing and testing the new sensors. The follow-on steps were to apply the lessons learned towards a new in-water profiler based on a kite-shaped backplane for mounting the light sensors. The next level of sophistication involved evaluating new radiometers emerging from a development activity based on so-called microradiometers. The exploitation of microradiometers resulted in an in-water profiling system, which includes a sensor networking capability to control ancillary sensors like a shadowband or global positioning system (GPS) device. A principal advantage of microradiometers is their flexibility in producing, interconnecting, and maintaining instruments. The full problem set for collecting sea-truth data--whether in coastal waters or the open ocean-- involves other aspects of data collection that were improved for instruments measuring both AOPs and inherent optical properties (IOPs), if the uncertainty budget is to be minimized. New capabilities associated with deploying solar references were developed as well as a compact solution for recovering in-water instrument systems from small boats
Optical Sensors for Planetary Radiant Energy (OSPREy): Calibration and Validation of Current and Next-Generation NASA Missions
A principal objective of the Optical Sensors for Planetary Radiance Energy (OSPREy) activity is to establish an above-water radiometer system as a lower-cost alternative to existing in-water systems for the collection of ground-truth observations. The goal is to be able to make high-quality measurements satisfying the accuracy requirements for the vicarious calibration and algorithm validation of next-generation satellites that make ocean color and atmospheric measurements. This means the measurements will have a documented uncertainty satisfying the established performance metrics for producing climate-quality data records. The OSPREy approach is based on enhancing commercial-off-the-shelf fixed-wavelength and hyperspectral sensors to create hybridspectral instruments with an improved accuracy and spectral resolution, as well as a dynamic range permitting sea, Sun, sky, and Moon observations. Greater spectral diversity in the ultraviolet (UV) will be exploited to separate the living and nonliving components of marine ecosystems; UV bands will also be used to flag and improve atmospheric correction algorithms in the presence of absorbing aerosols. The short-wave infrared (SWIR) is expected to improve atmospheric correction, because the ocean is radiometrically blacker at these wavelengths. This report describes the development of the sensors, including unique capabilities like three-axis polarimetry; the documented uncertainty will be presented in a subsequent report
A prospective, randomized trial of complete avoidance of steroids in liver transplantation with followâup of over 7âyears
Objectives Steroids are a mainstay of treatment in orthotopic liver transplantation ( OLT ) and are associated with significant morbidity. This trial was conducted to assess the efficacy of steroids avoidance. Methods Patients undergoing OLT between June 2002 and April 2005 were entered into a prospective, randomized trial of complete steroids avoidance and followed until November 2011. Recipients received either standard therapy ( n = 50) or complete steroids avoidance ( n = 50). Analyses were performed on an intentionâtoâtreat basis. The mean followâup of all recipients was 2095 ± 117 days. Sixteen (32%) recipients randomized to the steroids avoidance group ultimately received steroids for clinical indications. Results Incidences of diabetes and hypertension prior to or after OLT were similar in both groups, as was the incidence of rejection. Patient and graft survival rates at 1, 3 and 5 years were lower in the steroids avoidance group than in the standard therapy group (patient survival: 1âyear, 80% versus 86%; 3âyear, 68% versus 76%; 5âyear, 60% versus 72%; graft survival: 1âyear, 76% versus 76%; 3âyear, 64% versus 74%; 5âyear, 56% versus 72%), but the differences were not statistically different. Conclusions Complete steroids avoidance provides liver transplant recipients with minimal benefit and appears to result in a concerning trend towards decreased graft and recipient survival. The present data support the use of at least a short course of steroids after liver transplantation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97180/1/hpb576.pd
Conceptualising characteristics of resources withdrawal from medical services : a systematic qualitative synthesis
Abstract: Background: Terms used to describe government-led resource withdrawal from ineffective and unsafe medical services, including ârationingâ and âdisinvestmentâ, have tended to be used interchangeably, despite having distinct characteristics. This lack of descriptive precision for arguably distinct terms contributes to the obscurity that hinders effective communication and the achievement of evidence-based decision-making. The objectives of this study are to (1) identify the various terms used to describe resource withdrawal and (2) propose definitions for the key or foundational terms, which includes a clear description of the unique characteristics of each. Methods: This is a systematic qualitative synthesis of characteristics and terms found through a search of the academic and grey literature. This approach involved identifying commonly used resource withdrawal terms, extracting data about resource withdrawal characteristics associated with each term and conducting a comparative analysis by categorising elements as antecedents, attributes or outcomes. Results: Findings from an analysis of 106 documents demonstrated that terms used to describe resource withdrawal are inconsistently defined and applied. The characteristics associated with these terms, mainly antecedents and attributes, are used interchangeably by many authors but are differentiated by others. Our analysis resulted in the development of a framework that organises these characteristics to demonstrate the unique attributes associated with each term. To enhance precision, these terms were classified as either policy options or patient health outcomes and refined definitions for rationing and disinvestment were developed. Rationing was defined as resource withdrawal that denies, on average, patient health benefits. Disinvestment was defined as resource withdrawal that results in, on average, improved or no change in health benefits. Conclusion: Agreement on the definition of various resource withdrawal terms and their key characteristics is required for transparent government decision-making regarding medical service withdrawal. This systematic qualitative synthesis presents the proposed definitions of resource withdrawal terms that will promote consistency, benefit public policy dialogue and enhance the policy-making process for health systems
The Effective Lagrangian in the Randall-Sundrum Model and Electroweak Physics
We consider the two-brane Randall-Sundrum (RS) model with bulk gauge fields.
We carefully match the bulk theory to a 4D low-energy effective Lagrangian. In
addition to the four-fermion operators induced by KK exchange we find that
large negative S and T parameters are induced in the effective theory. This is
a tree-level effect and is a consequence of the shapes of the W and Z wave
functions in the bulk. Such effects are generic in extra dimensional theories
where the standard model (SM) gauge bosons have non-uniform wave functions
along the extra dimension. The corrections to precision electroweak observables
in the RS model are mostly dominated by S. We fit the parameters of the RS
model to the experimental data and find somewhat stronger bounds than
previously obtained; however, the standard model bound on the Higgs mass from
precision measurements can only be slightly relaxed in this theory.Comment: 16 pages, LaTeX, 1 figure included, uses JHEP.cls, extended
introduction, added reference
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