Remote Sensing of Giant Reed with QuickBird Satellite Imagery

QuickBird high resolution (2.8 m) satellite imagery was evaluated for distinguishing giant reed ( Arundo donax L.) infestations along the Rio Grande in southwest Texas. (PDF has 5 pages.

Preflare magnetic and velocity fields

A characterization is given of the preflare magnetic field, using theoretical models of force free fields together with observed field structure to determine the general morphology. Direct observational evidence for sheared magnetic fields is presented. The role of this magnetic shear in the flare process is considered within the context of a MHD model that describes the buildup of magnetic energy, and the concept of a critical value of shear is explored. The related subject of electric currents in the preflare state is discussed next, with emphasis on new insights provided by direct calculations of the vertical electric current density from vector magnetograph data and on the role of these currents in producing preflare brightenings. Results from investigations concerning velocity fields in flaring active regions, describing observations and analyses of preflare ejecta, sheared velocities, and vortical motions near flaring sites are given. This is followed by a critical review of prevalent concepts concerning the association of flux emergence with flare

Limitations of Absolute Current Densities Derived from the Semel & Skumanich Method

Semel and Skumanich proposed a method to obtain the absolute electric current density, |Jz|, without disambiguation of 180 degree in the transverse field directions. The advantage of the method is that the uncertainty in the determination of the ambiguity in the magnetic azimuth is removed. Here, we investigate the limits of the calculation when applied to a numerical MHD model. We found that the combination of changes in the magnetic azimuth with vanishing horizontal field component leads to errors, where electric current densities are often strong. Where errors occur, the calculation gives |Jz| too small by factors typically 1.2 ~ 2.0.Comment: 10 pages, 4 figures. To appear on Science in China Series G: Physics, Mechanics & Astronomy, October 200

Stimulated radiative laser cooling

Building a refrigerator based on the conversion of heat into optical energy is an ongoing engineering challenge. Under well-defined conditions, spontaneous anti-Stokes fluorescence of a dopant material in a host matrix is capable of lowering the host temperature. The fluorescence is conveying away a part of the thermal energy stored in the vibrational oscillations of the host lattice. In particular, applying this principle to the cooling of (solid-state) lasers opens up many potential device applications, especially in the domain of high-power lasers. In this paper, an alternative optical cooling scheme is outlined, leading to radiative cooling of solid-state lasers. It is based on converting the thermal energy stored in the host, into optical energy by means of a stimulated nonlinear process, rather than a spontaneous process. This should lead to better cooling efficiencies and a higher potential of applying the principle for device applications

Modelling S. choleraesuis infection by oral route of inoculation; titration of dose strength

Salmonella infections cost the United States swine industry more than 100 million dollars annually (Schwartz, 1990). In the United States, salmonellosis caused by Salmonella choleraesuis, the etiologic agent of swine parathyphoid, occurs most frequently. While pigs can be exposed to broad host range salmonellae, such as Salmonella typhimurium, from a variety of sources, S. choleraesuis is a host adapted pathogen rarely isolated from non-swine sources (Schwartz, 1990). Thus, natural infection of new animals by S. choleraesuis occurs primarily via horizontal transmission from infected animals which shed the pathogen from their gastrointestinal tract

Competitive exclusion of Salmonella serovar Typhimurium from the gut of early weaned pigs

Strategies to curb infection of pigs by Salmonella are sought throughout the fann to table continuum. Competitive exclusion (CE), which involves colonizing the gastrointestinal tract of young animals with a healthy gut microflora, has been shown to be an attractive strategy for protecting poultry from salmonellae infections (4-7, 14, 16-17, 19-20, 23). More recent evidence suggests that CE may enhance resistance of young pigs against infections by Salmonella serovar Choleraesuis (2, 9, 15, 21), the serotype responsible for the vast majority of swine salmonellosis cases in the United States (22). Salmonella serovar Typhimurium can also infect and cause disease in swine and may be considered a greater food safety concern than Salmonella Choleraesuis but until now, reports regarding the effect of CE treatment on colonization resistance of early weaned pigs to this serotype have been few if not nonexistent

Topological Organization of Ventral Tegmental Area Connectivity Revealed by Viral-Genetic Dissection of Input-Output Relations

Viral-genetic tracing techniques have enabled mesoscale mapping of neuronal connectivity by teasing apart inputs to defined neuronal populations in regions with heterogeneous cell types. We previously observed input biases to output-defined ventral tegmental area dopamine (VTA-DA) neurons. Here, we further dissect connectivity in the VTA by defining input-output relations of neurochemically and output-defined neuronal populations. By expanding our analysis to include input patterns to subtypes of excitatory (vGluT2-expressing) or inhibitory (GAD2-expressing) populations, we find that the output site, rather than neurochemical phenotype, correlates with whole-brain inputs of each subpopulation. Lastly, we find that biases in input maps to different VTA neurons can be generated using publicly available whole-brain output mapping datasets. Our comprehensive dataset and detailed spatial analysis suggest that connection specificity in the VTA is largely a function of the spatial location of the cells within the VTA

Effect of competitive exclusion on transmission of Salmonella choleraesuis between early weaned pigs

Salmonella serovar Choleraesuis accounts for the vast majority of diagnosed cases of swine salmonellosis in the United States (24). Enterocolitis caused by Salmonella serovar Typhimurium ranks second as a cause of salmonellosis (24) but this organism ranks high as an important food borne pathogen. Infection by Salmonella Typhimurium and other broad host range serotypes can occur through exposure to contaminated feedstuffs, infected rodents, birds or other swine. In contrast, transmission of the host-adapted serotype, Salmonella Choleraesuis, is thought to occur primarily via contact with infected carrier pigs (24) which may shed !he palhogen from their gastrointestinal and possibly their respiratory tract

Rabies screen reveals GPe control of cocaine-triggered plasticity.

Identification of neural circuit changes that contribute to behavioural plasticity has routinely been conducted on candidate circuits that were preselected on the basis of previous results. Here we present an unbiased method for identifying experience-triggered circuit-level changes in neuronal ensembles in mice. Using rabies virus monosynaptic tracing, we mapped cocaine-induced global changes in inputs onto neurons in the ventral tegmental area. Cocaine increased rabies-labelled inputs from the globus pallidus externus (GPe), a basal ganglia nucleus not previously known to participate in behavioural plasticity triggered by drugs of abuse. We demonstrated that cocaine increased GPe neuron activity, which accounted for the increase in GPe labelling. Inhibition of GPe activity revealed that it contributes to two forms of cocaine-triggered behavioural plasticity, at least in part by disinhibiting dopamine neurons in the ventral tegmental area. These results suggest that rabies-based unbiased screening of changes in input populations can identify previously unappreciated circuit elements that critically support behavioural adaptations

Design agency:prototyping multi-agent systems in architecture

This paper presents research on the prototyping of multi-agent systems for architectural design. It proposes a design exploration methodology at the intersection of architecture, engineering, and computer science. The motivation of the work includes exploring bottom up generative methods coupled with optimizing performance criteria including for geometric complexity and objective functions for environmental, structural and fabrication parameters. The paper presents the development of a research framework and initial experiments to provide design solutions, which simultaneously satisfy complexly coupled and often contradicting objectives. The prototypical experiments and initial algorithms are described through a set of different design cases and agents within this framework; for the generation of façade panels for light control; for emergent design of shell structures; for actual construction of reciprocal frames; and for robotic fabrication. Initial results include multi-agent derived efficiencies for environmental and fabrication criteria and discussion of future steps for inclusion of human and structural factors