A simple Hebbian/anti-Hebbian network learns the sparse, independent components of natural images

Slightly modified versions of an early Hebbian/anti-Hebbian neural network are shown to be capable of extracting the sparse, independent linear components of a prefiltered natural image set. An explanation for this capability in terms of a coupling between two hypothetical networks is presented. The simple networks presented here provide alternative, biologically plausible mechanisms for sparse, factorial coding in early primate vision.     

Heart rate variability and newborn heart rate responses to illumination changes.

Investigated heart rate (HR) response patterns to the onset and offset of a 30-sec increase in illumination in 16 human newborns. Ss were divided into 2 groups based on a measure of pretrial HR variability. Only Ss with the high pretrial HR variability responded significantly to the change in stimulation. The response to onset was characterized by a significant quartic trend containing both decelerative and accelerative components. The response to offset only approached significance and had a pattern similar to the onset response. Although the occurrence of systematic response patterns was related to the level of pretrial HR variability, this measure of autonomic lability may have been related to influences associated with delivery and not to stable individual differences. (16 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Geochemical Framework for Understanding Residue Properties

Crude oils, and the residual fractions thereof, vary widely in many relevant properties. Thus, a detailed characterization of a single residue stream or even a number of residue streams from one region may not be very relevant in a different part of the world. We have therefore attempted to develop a framework for understanding residue properties in a generic fashion. A detailed analysis of 11 vacuum residue fractions from a wide variety of crude oils resulted in a general model for understanding the composition and processability of residue streams. This model is based on the geochemical origin (kerogen type) and the maturity of the crude oil. The different origin of kerogen I (paraffinic) residues, compared with the more conventional kerogen II residues, is reflected in a large number of properties and also in a larger variability in these properties. However, upon maturation, the average properties of kerogen I residues and kerogen II residues converge so that mature residues of both kerogen types have much in common (low S content, low metals content, high H/C ratio etc). Maturation is found to have a negative effect on the stability and coking tendency of the residue fraction. NMR data reveal that the asphalthenes become more aromatic upon ageing, whereas the maltenes (non-asphalthenes) become less aromatic, thus causing an increasing gap in aromaticity between these fractions. Significant differences in asphaltene molecular structure between kerogen I and kerogen II residues were observed. The analytical data suggest that the concept of kerogen type and maturity may be a useful tool in describing and understanding residue characteristics and assist in optimizing feedstock selection for residue conversion processes and other residue applications (fuel oils, bitumen), as well as in understanding fouling and coking phenomena. Further research is required to establish the trends shown in this paper.     

Effects of delayed housing of broiler chicks and three different types of waterers on broiler performance

The performance of broilers was examined under different days of placement (after hatching) and with three different types of waterers: 1) an automatic satellite waterer; 2) a broiler Plasson waterer; and 3) a regular Plasson waterer with a plastic ring in the trough of the waterer for 3 d. Male broiler chicks (2,106) from a commercial strain were randomly placed in 27 litter floor pens, with 9 pens per day of placement and waterer treatments. The broilers consumed feed and water ad libitum and mortality was recorded. The broilers were weighed at day of placement, at 7 and 49 d from day of placement and at 28 and 49 d from day of hatch. There was a difference in body weight (P < .05) among the broilers on the day of placement, with those on the day of hatch being heavier. There was no difference in body weights or feed conversion taken after the broilers were on feed for 7 and 49 d after placement. The broilers placed on the 3rd d after hatching had a higher (P < .05) mortality rate at 28 d of age than the other two groups. There was no difference in body weight, feed conversion, or mortality within the three different waterer treatments except for the broilers on the Plasson with the ring, which was higher in mortality percentage (P < .05) than the broilers on the broiler Plasson waterer. The broilers placed in the pens with the regular Plasson waterer did not get wet from climbing into the water during the first few days as did the broilers in the pens with the automatic satellite waterer or the Plasson waterer with the ring.     

Hand-held microanalytical instrument for chip-based electrophoretic separations of proteins

The design, fabrication, and demonstration of a hand-held microchip-based analytical instrument for detection and identification of proteins and other biomolecules are reported. The overall system, referred to as muChemLab, has a modular design that provides for reliability and flexibility and that facilitates rapid assembly, fluid and microchip replacement, troubleshooting, and sample analysis. Components include two independent separation modules that incorporate interchangeable fluid cartridges, a 2-cm-square fused-silica microfluidic chip, and a miniature laser-induced fluorescence detection module. A custom O-ring sealed manifold plate connects chip access ports to a fluids cartridge and a syringe injection port and provides sample introduction and world-to-chip interface. Other novel microfluidic connectors include capillary needle fittings for fluidic connection between septum-sealed fluid reservoirs and the manifold housing the chip, enabling rapid chip priming and fluids replacement. Programmable high-voltage power supplies provide bidirectional currents up to 100 microAlpha at 5000 V, enabling real-time current and voltage monitoring and facilitating troubleshooting and methods development. Laser-induced fluorescence detection allows picomolar (10(-11) M) detection sensitivity of fluorescent dyes and nanomolar sensitivity (10(-9) M) for fluorescamine-labeled proteins. Migration time reproducibility was significantly improved when separations were performed under constant current control (0.5-1%) as compared to constant voltage control (2-8%).     

Journal evaluations: Are they really evaluations of authors?

Investigated whether particular methods of journal evaluations are biased in favor of either natural science (NSC) or social science (SSC) psychology journals by comparing the mean number of authors per article and pages per journal in 40 NSC and SSC psychology journals. There were significant differences across the 2 types of journals with regard to number of authors per article and the mean number of pages attributable to each author. The hypothesis that NSC articles have more authors than SSC articles was confirmed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Heart rate conditioning in newborn infants: Relationships among conditionability, heart rate variability, and sex.

Evaluated trace conditioning in 20 newborn infants by examining heart rate responses to the conditioned stimulus (CS), in anticipation of the unconditioned stimulus (UCS) and in the absence of the UCS. 2 sets of analyses were performed using subgroups based on preexperimental heart rate variability and sex. Preexperimental heart rate variability was related only to the response to the CS, with only the high-variance Ss showing a conditioned deceleration and exhibiting a change in response across trial blocks. Only the females exhibited conditioned decelerations in response to the CS and in anticipation of the UCS. In the absence of the UCS, only the experimental group as a whole responded with a deceleration. The relationship between sex and heart rate variability was also examined. Data suggest that females tend to have higher levels of heart rate variability which parallels their greater conditionability. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Using Pre-construction Validation to Regulate Urban Skylines

This article describes best practices from contemporary scientific protocols that can be used to perform pre-construction validation of urban design guidelines. Because of the prominence of skylines in the urban landscape, their regulation represents a prime candidate for applying design guidelines. We tested guidelines for three prospective skyline factors: overall skyline shape (convex, concave, or flat), number of turns in the roofline of individual buildings (4, 8, or 12), and level of variance in four attributes of individual buildings: height, width, depth, and setback (low, medium, or high). Level of variance in building attributes had the strongest effect on judged pleasantness. The respondents preferred rugged skylines over simple ones, whatever their overall shape. These findings suggest that regulations for skyline appearance should focus on variances in the four building attributes.