Galactic extinction and Abell clusters

In this paper, we present the results of comparing the angular distribution of Abell clusters with Galactic HI measurements. For most subsamples of clusters considered, their positions on the sky appear to be anti-correlated with respect to the distribution of HI column densities. The statistical significance of these observed anti-correlations is a function of both richness and distance class, with the more distant and/or richest systems having the highest significance (~3 sigma). The lower richness, nearby clusters appear to be randomly distributed compared to the observed Galactic HI column density.Comment: 5 pages, uuencoded compressed postscript file. Figures included. Accepted by MNRA

Pseudomonas aeruginosa can be detected in a polymicrobial competition model using impedance spectroscopy with a novel biosensor

Electrochemical Impedance Spectroscopy (EIS) is a powerful technique that can be used to elicit information about an electrode interface. In this article, we highlight six principal processes by which the presence of microorganisms can affect impedance and show how one of these - the production of electroactive metabolites - changes the impedance signature of culture media containing Pseudomonas aeruginosa. EIS, was used in conjunction with a low cost screen printed carbon sensor to detect the presence of P. aeruginosa when grown in isolation or as part of a polymicrobial infection with Staphylococcus aureus. By comparing the electrode to a starting measurement, we were able to identify an impedance signature characteristic of P. aeruginosa. Furthermore, we are able to show that one of the changes in the impedance signature is due to pyocyanin and associated phenazine compounds. The findings of this study indicate that it might be possible to develop a low cost sensor for the detection of P. aeruginosa in important point of care diagnostic applications. In particular, we suggest that a development of the device described here could be used in a polymicrobial clinical sample such as sputum from a CF patient to detect P. aeruginosa

Gaze-dependent topography in human posterior parietal cortex.

The brain must convert retinal coordinates into those required for directing an effector. One prominent theory holds that, through a combination of visual and motor/proprioceptive information, head-/body-centered representations are computed within the posterior parietal cortex (PPC). An alternative theory, supported by recent visual and saccade functional magnetic resonance imaging (fMRI) topographic mapping studies, suggests that PPC neurons provide a retinal/eye-centered coordinate system, in which the coding of a visual stimulus location and/or intended saccade endpoints should remain unaffected by changes in gaze position. To distinguish between a retinal/eye-centered and a head-/body-centered coordinate system, we measured how gaze direction affected the representation of visual space in the parietal cortex using fMRI. Subjects performed memory-guided saccades from a central starting point to locations “around the clock.” Starting points varied between left, central, and right gaze relative to the head-/body midline. We found that memory-guided saccadotopic maps throughout the PPC showed spatial reorganization with very subtle changes in starting gaze position, despite constant retinal input and eye movement metrics. Such a systematic shift is inconsistent with models arguing for a retinal/eye-centered coordinate system in the PPC, but it is consistent with head-/body-centered coordinate representations

Market Response to Two Alternative Packages for U.S. No. 2 Grapefruit

Packages, U.S. No. 2 Grapefruits, Grapefruit, Alternatives, Crop Production/Industries, Food Consumption/Nutrition/Food Safety, Marketing,

Designing III-V Multijunction Solar Cells on Silicon

Single junction Si solar cells dominate photovoltaics but are close to their efficiency limits. This paper presents ideal limiting efficiencies for tandem and triple junction multijunction solar cells subject only to the constraint of the Si bandgap and therefore recommending optimum cell structures departing from the single junction ideal. The use of III-V materials is considered, using a novel growth method capable of yielding low defect density III-V layers on Si. In order to evaluate the real potential of these proposed multijunction designs, a quantitative model is presented, the strength of which is the joint modelling of external quantum efficiency and current-voltage characteristics using the same parameters. The method yields a single parameter fit in terms of the Shockley-Read-Hall lifetime. This model is validated by fitting experimental data of external quantum efficiency, dark current, and conversion efficiency of world record tandem and triple junction cells under terrestrial solar spectra without concentration. We apply this quantitative model to the design of tandem and triple junction solar cells, yielding cell designs capable of reaching efficiencies without concentration of 32% for the best tandem cell and 36% for the best triple junction cell. This demonstrates that efficiencies within a few percent of world records are realistically achievable without the use of concentrating optics, with growth methods being developed for multijunction cells combining III-V and Si materials.Comment: Preprint of the paper submitted to the journal Progress in Photovoltaics, selected by the Executive Committee of the 28th EU PVSEC 2013 for submission to Progress in Photovoltaics. 10 pages, 7 figure

Texas Fresh Citrus Shipments by Market Areas, 1973-74

Texas Citrus, Citrus, Shipments, Market Areas, Crop Production/Industries, Marketing,