5,598 research outputs found
Conformal Orthosymplectic Quantum Mechanics
We present the most general curvature obstruction to the deformed parabolic
orthosymplectic symmetry subalgebra of the supersymmetric quantum mechanical
models recently developed to describe Lichnerowicz wave operators acting on
arbitrary tensors and spinors. For geometries possessing a
hypersurface-orthogonal homothetic conformal Killing vector we show that the
parabolic subalgebra is enhanced to a (curvature-obstructed) orthosymplectic
algebra. The new symmetries correspond to time-dependent conformal symmetries
of the underlying particle model. We also comment on generalizations germane to
three dimensions and new Chern--Simons-like particle models.Comment: 27 pages LaTe
Supporting more able and talented pupils in primary schools
"This survey evaluates the effectiveness of strategies used by primary schools and local authorities to support and challenge more able and talented pupils.
Overall, most more able and talented pupils are not challenged enough and too few pupils achieve above the expected levels at the end of key stages 1 and 2.
Provision for more able and talented pupils varies too much across Wales. In the few primary schools with the best provision, thorough analysis of data and assessment outcomes helps to identify more able and talented pupils. In these few schools, more able and talented pupils are supported through a range of additional provision and their progress tracked and monitored carefully. Parents understand the school’s approach to providing additional support for more able and talented pupils.
More able and talented pupils gain most in schools that promote individualised or personalised approaches to learning and they benefit particularly from having control over how and what they learn.
However, in the majority of primary schools, more able and talented pupils are not identified and do not receive appropriate support. Teachers in these schools do not have the expertise to identify, support or track the progress of more able and talented pupils.
Transition arrangements between primary and secondary schools often do not provide enough continuity and progression in the education of more able and talented pupils.
Few local authorities use data to monitor the progress of more able and talented pupils or promote the sharing of best practice between schools. School improvement officers rarely discuss more able and talented pupils during their visits to schools." - page 1
Ionic charge distributions of energetic particles from solar flares
The effects which solar flare X-rays have on the charge states of solar cosmic rays is determined quantitatively. Rather than to characterize the charge distribution by temperature alone, it is proposed that the X-ray flux at the acceleration site also is used. The effects of flare X-rays are modeled mathematically
Old carbon contributes to aquatic emissions of carbon dioxide in the Amazon
Knowing the rate at which carbon is cycled is crucial to understanding the dynamics of carbon transfer pathways. Recent technical developments now support measurement of the <sup>14</sup>C age of evaded CO<sub>2</sub> from fluvial systems, which provides an important "fingerprint" of the source of C. Here we report the first direct measurements of the <sup>14</sup>C age of effluxed CO<sub>2</sub> from two small streams and two rivers within the western Amazonian Basin. The rate of degassing and hydrochemical controls on degassing are also considered. We observe that CO<sub>2</sub> efflux from all systems except for the seasonal small stream was <sup>14</sup>C -depleted relative to the contemporary atmosphere, indicating a contribution from "old" carbon fixed before ~ 1955 AD. Further, "old" CO<sub>2</sub> was effluxed from the perennial stream in the rainforest; this was unexpected as here connectivity with the contemporary C cycle is likely greatest. The effluxed gas represents all sources of CO<sub>2</sub> in the aquatic system and thus we used end-member analysis to identify the relative inputs of fossil, modern and intermediately aged C. The most likely solutions indicated a contribution from fossil carbon sources of between 3 and 9% which we interpret as being derived from carbonate weathering. This is significant as the currently observed intensification of weather has the potential to increase the future release of old carbon, which can be subsequently degassed to the atmosphere, and so renders older, slower C cycles faster. Thus <sup>14</sup>C fingerprinting of evaded CO<sub>2</sub> provides understanding which is essential to more accurately model the carbon cycle in the Amazon Basin
Multi-limbed locomotion systems for space construction and maintenance
A well developed technology of coordination of multi-limbed locomotory systems is now available. Results from a NASA sponsored study of several years ago are presented. This was a simulation study of a three-limbed locomotion/manipulation system. Each limb had six degrees of freedom and could be used either as a locomotory grasping hand-holds, or as a manipulator. The focus of the study was kinematic coordination algorithms. The presentation will also include very recent results from the Adaptive Suspension Vehicle Project. The Adaptive Suspension Vehicle (ASV) is a legged locomotion system designed for terrestrial use which is capable of operating in completely unstructured terrain in either a teleoperated or operator-on-board mode. Future development may include autonomous operation. The ASV features a very advanced coordination and control system which could readily be adapted to operation in space. An inertial package with a vertical gyro, and rate gyros and accelerometers on three orthogonal axes provides body position information at high bandwidth. This is compared to the operator's commands, injected via a joystick to provide a commanded force system on the vehicle's body. This system is, in turn, decomposed by a coordination algorithm into force commands to those legs which are in contact with the ground
A search for outflows from X-ray bright points in coronal holes
Properties of X-ray bright points using two of the instruments on Solar Maximum Mission were investigated. The mass outflows from magnetic regions were modeled using a two dimensional MHD code. It was concluded that mass can be detected from X-ray bright points provided that the magnetic topology is favorable
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Pancreatic adaptive responses in alcohol abuse: Role of the unfolded protein response.
The majority of those who drink excessive amounts of alcohol do not develop pancreatic disease. One overarching hypothesis is that alcohol abuse requires additional risk factors, either environmental or genetic, for disease to occur. However, another reason be a result of alcohol-induced activation of adaptive systems that protect the pancreas from the toxic effects of alcohol. We show that mechanisms within the unfolded protein response (UPR) of the endoplasmic reticulum (ER) that can lead to protection of the pancreas from pancreatic diseases with alcohol abuse. The remarkable ability of the pancreas to adapt its machinery to alcohol abuse using UPR systems and continue functioning is the likely reason that pancreatitis from alcohol abuse does not occur in the majority of heavy drinkers. These findings indicate that methods to enhance the protective responses of the UPR can provide opportunities for prevention and treatment of pancreatic diseases
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