Method for reducing snap in magnetic amplifiers

Method of reducing snap in magnetic amplifiers uses a degenerative feedback circuit consisting of a resistor and a separate winding on a magnetic core. The feedback circuit extends amplifier range by allowing it to be used at lower values of output current

On the Evolution of Factfinding in Public Employee Negotiations

Dr. Word is an Assistant Professor in the Department of Economics in the School of Business, Georgia Southern College

Basic Science and Risk Communication: A Dialogue-Based Study

The authors use ethnographic analysis of a focus group discussion between scientists and laypersons to study information exchange in risk communication

Experimental chronic noise is related to elevated fecal corticosteroid metabolites in lekking male greater Sage-Grouse (Centrocercus urophasianus).

There is increasing evidence that individuals in many species avoid areas exposed to chronic anthropogenic noise, but the impact of noise on those who remain in these habitats is unclear. One potential impact is chronic physiological stress, which can affect disease resistance, survival and reproductive success. Previous studies have found evidence of elevated stress-related hormones (glucocorticoids) in wildlife exposed to human activities, but the impacts of noise alone are difficult to separate from confounding factors. Here we used an experimental playback study to isolate the impacts of noise from industrial activity (natural gas drilling and road noise) on glucocorticoid levels in greater sage-grouse (Centrocercus urophasianus), a species of conservation concern. We non-invasively measured immunoreactive corticosterone metabolites from fecal samples (FCMs) of males on both noise-treated and control leks (display grounds) in two breeding seasons. We found strong support for an impact of noise playback on stress levels, with 16.7% higher mean FCM levels in samples from noise leks compared with samples from paired control leks. Taken together with results from a previous study finding declines in male lek attendance in response to noise playbacks, these results suggest that chronic noise pollution can cause greater sage-grouse to avoid otherwise suitable habitat, and can cause elevated stress levels in the birds who remain in noisy areas

X-Ray Resonant Scattering as a Direct Probe of Orbital Ordering in Transition-Metal Oxides

X-ray resonant scattering at the K-edge of transition metal oxides is shown to measure the orbital order parameter, supposed to accompany magnetic ordering in some cases. Virtual transitions to the 3d-orbitals are quadrupolar in general. In cases with no inversion symmetry, such as V$_2$O$_3$, treated in detail here, a dipole component enhances the resonance. Hence, we argue that the detailed structure of orbital order in V$_2$O$_3$ is experimentally accessible.Comment: LaTex using RevTex, 4 pages and two included postscript figure

Theory for Phase Transitions in Insulating Vanadium Oxide

We show that the recently proposed S=2 bond model with orbital degrees of freedom for insulating V$_{2}$O$_{3}$ not only explains the anomalous magnetic ordering, but also other mysteries of the magnetic phase transition. The model contains an additional orbital degree of freedom that exhibits a zero temperature quantum phase transtion in the Ising universality class.Comment: 5 pages, 2 figure

Orbitally Degenerate Spin-1 Model for Insulating V2O3

Motivated by recent neutron, X-ray absorption and resonant scattering experiments, we revisit the electronic structure of V2O3. We propose a model in which S=1 V3+ ions are coupled in the vertical V-V pairs forming two-fold orbitally degenerate configurations with S=2. Ferro-orbital ordering of the V-V pairs gives a description which is consistent with all experiments in the antiferromagnetic insulating phase.Comment: 4 pages, including three figure

Evaluation of older bay mud sediment from Richmond Harbor, California

The older, bay mud (OBM) unit predates modem man and could act as a barrier to the downward transport of contaminants from the younger bay mud (YBM) because of its hard-packed consistency. However, its chemical and biological nature have not been well characterized. Battelle/Marine Sciences Laboratory (MSL) conducted three independent studies of OBM sediment in January 1993, January 1994, and October 1994. These studies evaluated potential chemical contamination and biological effects of OBM that could occur as a result of dredging and disposal activities. These evaluations were performed by conducting chemical analysis, solid-phase toxicity tests, suspended- particulate-phase (SPP) toxicity tests, and bioaccumulation tests on the OBM sediment. If the sediment chemistry and toxicity results showed no or minimal contamination and toxicological responses, then either the OBM could be left exposed in Richmond Harbor after dredging the YBM without leaving a source of contamination, or if the project depths necessitate, the OBM would be acceptable for disposal at an appropriate disposal site

How birds cope physiologically and behaviourally with extreme climatic events

As global climate change progresses, the occurrence of potentially disruptiveclimatic events such as storms are increasing in frequency, duration and inten-sity resulting in higher mortality and reduced reproductive success. Whatconstitutes an extreme climatic event? First we point out that extreme climaticevents in biological contexts can occur in any environment. Focusing on fieldand laboratory data on wild birds we propose a mechanistic approach to defin-ing and investigating what extreme climatic events are and how animals copewith them at physiological and behavioural levels. The life cycle of birds ismade up of life-history stages such as migration, breeding and moult thatevolved to match a range of environmental conditions an individual mightexpect during the year. When environmental conditions deteriorate anddeviate from the expected range then the individual must trigger copingmechanisms (emergency life-history stage) that will disrupt the temporal pro-gression of life-history stages, but enhance survival. Using the framework ofallostasis, we argue that an extreme climatic event in biological contexts canbe defined as when the cumulative resources available to an individual areexceeded by the sum of its energetic costs—a state called allostatic overload.This allostatic overload triggers the emergency life-history stage that tempor-arily allows the individual to cease regular activities in an attempt to surviveextreme conditions. We propose that glucocorticoid hormones play a majorrole in orchestrating coping mechanisms and are critical for enduring extremeclimatic events.This article is part of the themed issue ‘Behavioural, ecological andevolutionary responses to extreme climatic events’