Using a defined and measured Personal Software Process

Improved software processes lead to improved product quality. The Personal Software Process (PSP) is a framework of techniques to help engineers improve their performance-and that of their organizations-through a step-by-step, disciplined approach to measuring and analyzing their work. This article explains how the PSP is taught and how it applies to different software engineering tasks. The author reports some promising early results     

Strobe rearing prevents the convergence of inputs with different response timings onto area 17 simple cells

Strobe rearing prevents the convergence of inputs with different response timings onto area 17 simple cells. J. Neurophysiol. 80: 3005-3020, 1998. The preceding paper showed that the loss of direction selectivity in simple cells induced by strobe rearing reflects the elimination of spatially ordered response timing differences across the receptive field that underlie spatiotemporal (S-T) inseparability. Here we addressed whether these changes reflected an elimination of certain timings or an alteration in how timings were associated in single cells. Timing in receptive fields was measured using stationary bars undergoing sinusoidal luminance modulation at different temporal frequencies (0.5-6 Hz). For each bar position, response phase versus temporal frequency data were fit by a line to obtain two measures: absolute phase and latency. In normal cats, many individual simple cells display a wide range of timings; in layer 4, the mean range for absolute phase and latency was 0.21 cycles and 39 ms, respectively. Strobe rearing compressed the mean timing ranges in single cells, to 0.08 cycles and 31 ms, respectively, and this compression accounted for the loss of inseparability. A similar compression was measured in layer 6 cells. In contrast, the range of timing values across the simple-cell population was relatively normal. Single cells merely sampled narrower than normal regions of the timing space. We sought to understand these cortical changes in terms of how inputs from the lateral geniculate nucleus (LGN) may have been affected by strobe rearing. In normal cats, a wide range of absolute phase and latency values exists among lagged and nonlagged LGN cells, and these thalamic timings account for most of the cortical timings. Also, S-T inseparability in many simple cells can be attributed to the convergence of lagged and/or nonlagged inputs. Strobe rearing did not change the sampling of lagged and nonlagged cells, and the geniculate timings continued to account for most of the cortical timings. However, strobe rearing virtually eliminated cortical receptive fields with mixed lagged and nonlagged timing, and it compressed the timing range in cells dominated by one or the other geniculate type. Thus strobe rearing did not eliminate certain timings in LGN or cortex, but prevented the convergence of different timings on single cells. To account for these results, we propose a developmental model in which strobe stimulation alters the correlational structure of inputs based on their response timing. Only inputs with similar timing become associated on single cortical cells, and this produces S-T separable receptive fields that lack the ability to confer a preferred direction of motion.     

The MOS inversion layer as a minority carrier injector

In this paper we report the first experimental demonstration of the concept of MOS inversion layer injection (ILI). The new physical concept is based on the use of a MOS inversion layer as a minority carrier injector as part of a dynamic junction. The carrier injection of such a junction is entirely controlled by the MOS gate. Moreover, when the gate potential is reduced under the MOS threshold voltage, the junction collapses ensuring a very efficient turn-off mechanism. Based on this concept we propose two novel lateral three-terminal structures termed inversion layer diode (ILD) and inversion layer bipolar transistor (ILBT). The concept of inversion layer injection can be applied in power devices where effective MOS gate control of the active junctions is important     

Aberrant left pulmonary artery presenting as a right paratracheal mass in an adult

Aberrant left pulmonary artery, or pulmonary sling, is a rare variation of the pulmonary vasculature, with only one previous report of the condition being recognized in an adult. In this report a second case recognized de novo in an adult is presented. Both of these adults were evaluated because of right paratracheal masses which required differentiation from pulmonary malignancies. The barium swallow shows a characteristic indentation of the anterior esophageal wall and the lateral tomogram demonstrates absence of the left pulmonary artery from its normal position in the left hilum. The pulmonary arteriogram is diagnostic and allows avoidance of more invasive diagnostic measures.     

Practical applications of adaptive mesh refinement (Rezoning)

A collection of finite element problems that have been examined with a posteriori convergence measures is presented. Results show these local convergence measures can be used to indicate the quality of a finite element solution and to suggest boundaries for mesh rezones.     

Chlorophyll

The distribution of chlorophyll is considered, followed by an historical survey leading to the establishment of the chemical constitution of chlorophylls a and b. Their use as permitted food colours in many countries is discussed. A section gives the commercial production of coppered chlorophyll products for food colouring. Finally, the laboratory preparation, analysis and chromatographic examination of chlorophyll are described in some detail.     

What is important about McCollough effects? Reply to Allan and Siegel.

Criticism of P. C. Dodwell and G. K. Humphrey's (see record 1990-14039-001) functional theory of the McCollough effect (ME) is answered. L. Allan and S. Siegel (see record 1993-28482-001) claim that MEs can be explained as classical conditioning effects. It is not disputed that the association-forming process in MEs shares much in common with classical conditioning, but there are still problems, practical and theoretical, with this account. It also misdirects attention from more important matters. The role of MEs in assuring a proper fit between representation and environment is reasserted, which seems to be the strongest reason for studying these effects. The functional theory aims to model the processes of error correction by means of which valid representation of the environment is maintained. It therefore belongs in a different tradition from that proclaimed by its critics. (PsycINFO Database Record (c) 2010 APA, all rights reserved)