Comment on ``Spin Dependent Hopping and Colossal Negative Magnetoresistance in Epitaxial Nd0.52Sr0.48MnO3Nd_{0.52}Sr_{0.48}MnO_{3} Films in Fields up to 50 T''

Recently Wagner et al. [Phys. Rev. Lett. Vol. 81, P. 3980 (1998)] proposed that Mott's original model be modified to incorporate a hopping barrier which depends on the misorientation between the spins of electrons at the initial and the final states in an elementary process. They further claimed that using the model they can explain the observed scaling behavior-- negative-magnetoresistivity scaling proportional to the Brillouin function $\cal{B}$ in the ferromagnetic state and to ${\cal{B}}^2$ in the paramagnetic state. In this comment we argue that the modification needed for Mott's original model is different from that proposed by Wagner et al. and further show that our picture will successfully explain the observed scaling in the two regimes.Comment: 1 pag

Implementation and Outcome Evaluation of the Intensive Aftercare Program: Final Report

This Report presents the findings from a 5-year, multisite evaluation of the implementation and outcomes of the Intensive Aftercare Program (IAP), which was sponsored by the Office of Juvenile Justice and Delinquency Prevention (OJJDP). IAP was a major initiative in aftercare programming during the 1990s and has received considerable national attention. It addresses a critical problem facing the nation's juvenile justice system: how to effectively intervene with high-risk, incarcerated juvenile offenders who have demonstrated high recidivism rates and continue to offend as adults

Effects of scopolamine on matching to sample paradigm and related tests in human subjects

This was a double-blind placebo-controlled study with a cross-over design to examine the effects of scopolamine on cognitive functions in young healthy subjects. Scopolamine hydrobromide was administered subcutaneously to 12 subjects (mean +/- SD age 23.8 +/- 2.2 years) at doses of 0.3 and 0.6 mg in comparison with two placebo conditions. Scopolamine at both doses produced marked sedation as rated by subjects and an observer. In the continuous performance test, vigilance was impaired by both doses of scopolamine. The span of apprehension test showed differing results (only the high dose of scopolamine showed a performance decrement only in the three-character version of the span of apprehension test). Significant impairment by both doses of scopolamine was seen in immediate and delayed free recall, continuous visual recognition, running word recognition and running picture recognition. While scopolamine caused a significant slowing in average reaction times for simultaneous matching as well as for delayed matching, subjects made more errors under scopolamine compared to placebo only in delayed matching, not in simultaneous matching. Also, the main outcome of matching to sample showed significant effects only in delayed matching, not in simultaneous matching. Notable in this study is the incongruity between the simultaneous matching test and the span of apprehension test on the one hand and the other cognitive tests used on the other. These results demonstrated that scopolamine has a greater effect on memory than on attention. Thus, the scopolamine-induced effects in the present study seem to be more relevant to Alzheimer's disease in an advanced phase than to normal aging. Copyright (C) 2003 S. Karger AG, Basel

Antechamber facilitates loading and unloading of vacuum furnace

Antechamber facilitates the use of a furnace in which materials are heat treated in a high vacuum or a gas atmosphere. It has a high vacuum pumping system, a means for backfilling with a selected gas, an access door, glove ports, and a motor driven platform

Oil, Gas and Minerals: The Impact of Resource-Dependence and Governance on Sustainable Development

It has often been argued that oil, gas and minerals may have a negative impact on development as measured by income per capita. This does not say much about sustainability, which is critical for developing countries whose economic growth derives primarily from the exploitation of exhaustible resources

Remote sensing in Michigan for land resource management

The utilization of NASA earth resource survey technology as an important aid in the solution of current problems in resource management and environmental protection in Michigan is discussed. Remote sensing techniques to aid Michigan government agencies were used to achieve the following results: (1) provide data on Great Lakes beach recession rates to establish shoreline zoning ordinances; (2) supply technical justification for public acquisition of land to establish the St. John's Marshland Recreation Area; (3) establish economical and effective methods for performing a statewide wetlands survey; (4) accomplish a variety of regional resource management actions in the Upper Peninsula; and (5) demonstrate improved soil survey methods. The project disseminated information on remote sensing technology and provided advice and assistance to a number of users in Michigan

Communication on the science-policy interface: An overview of conceptual models

This article focuses on scholarly discourse on the science-policy interface, and in particular on questions regarding how this discourse can be understood in the course of history and which lessons we can learn. We aim to structure the discourse, show kinships of different concepts, and contextualize these concepts. For the twentieth century we identify three major phases that describe interactions on the science policy interface: the “linear phase” (1960s–1970s) when science informed policy-making in a unidirectional manner, the “interactive phase” (1970–2000s) when both sides found themselves in a continuous interaction, and the “embedded phase” (starting from the 2000s) when citizens’ voices come to be involved within this dialogue more explicitly. We show that the communicative relationship between science and policy-making has become more complex over time with an increasing number of actors involved. We argue that better skill-building and education can help to improve communication within the science-policy interface

Conformations of confined biopolymers

Nanoscale and microscale confinement of biopolymers naturally occurs in cells and has been recently achieved in artificial structures designed for nanotechnological applications. Here, we present an extensive theoretical investigation of the conformations and shape of a biopolymer with varying stiffness confined to a narrow channel. Combining scaling arguments, analytical calculations, and Monte Carlo simulations, we identify various scaling regimes where master curves quantify the functional dependence of the polymer conformations on the chain stiffness and strength of confinement.Comment: 5 pages, 4 figures, minor correction