Moving Objects with Transportation Modes: A Survey

Journal of Computer Science and Technology - In this article, we survey the main achievements of moving objects with transportation modes that span the past decade. As an important kind of human...     

Operative creation of left to right cardiac shunts: pulmonary functional sequelae

The tuberomammillary nucleus, a cluster of cells in the posterior hypothalamus, is the only known source of brain histamine. Although this nucleus is well described in terms of anatomy and neurochemistry, only little is known about its function. In the present study, the effect of a lesion in the region of this nucleus on intracranial self-stimulation was examined. Rats were implanted bilaterally with stimulating electrodes in the lateral hypothalamus and unilaterally with one lesion electrode in the region of this nucleus. After three days of baseline testing, half of the animals were given an electrolytic lesion. The animals were retested for six consecutive days, and thereafter weekly for another seven weeks. From the second day postlesion on, we unexpectedly found a gradual increase in response rate, which peaked on day 13 in the ipsilateral hemisphere only. Although there was no further increase over subsequent days, response rates remained elevated during the following seven weekly tests. The observed increase in lateral hypothalamic self-stimulation after an electrolytic lesion of the tuberomammillary nucleus is discussed in terms of an inhibitory system, possibly located in the region of this nucleus which, when removed by the lesion, increased reinforcing effects of the electrical brain stimulation. The fact that the effects on self-stimulation were lateralized to one hemisphere rules out an interpretation in terms of unspecific "performance" variables that could influence rate of lever pressing.     

Negative-gate to substrate erase transient simulation for flash memory

We present a detailed and accurate physics based transient simulation for modeling flash memory erasing. Typical cells are erased by moving electrons from the floating gate to the drain, source or substrate. This paper addresses substrate erasing using a negative gate bias voltage based on the approximate solution to Poisson’s equation. Substrate erasing using a negative gate bias voltage is one of the more prevalent ways to erase flash memory in currently available consumer products. Many papers have been published on this topic but rarely present detailed derivations and none using this exact set of equations to model this erasing process.     

Local Response to the Global Challenge: Comparing Local Economic Development Policies in a Regional Context

This article reports on a study that examined and compared the responses of six Greater Toronto Area (GTA) municipalities (two central, four suburban) to the challenges of global economic change. The study was carried out in a context characterized by the transfer to municipal governments of both administrative and financial responsibilities for local services by the government of the Province of Ontario. It found a strong tendency for the municipalities to compete with each other for economic advantage, despite efforts to convince them of the need for a cooperative region‐wide approach. Suburban governments relied principally on strategies to draw businesses away from the core, and this type of activity seemed likely to increase because of the municipalities' increased dependence on local property taxes. Nonetheless, study findings suggested several ways in which regional organizations or senior governments might help to strengthen regional economies without expecting municipal governments to surrender control over economic development policy.     

Performance Stability of the Harvard Ambient Particle Concentrator

The Harvard Ambient Particle Concentrator (HAPC) has been used routinely for exposure testing for a period of approximately three years. The stability of concentrator performance has been investigated as a function of local meteorological conditions, ambient particle concentrations, composition, and size distribution. Concentrator performance is characterized by the concentration enrichment factor (CEF), a ratio of concentrated particle mass (or sulfate) concentration to the ambient concentration. Over three years of normal operation, the mass and sulfate CEFs averaged 27.9 and 28.6, respectively. The majority of variability in the CEF was found to be related to the mass median aerodynamic diameter (MMAD) of ambient particles and to the HAPC's total operating pressure drop.

The 50% cutpoint of the HAPC is 0.15 μ m. Between 0.15 and 2.5 μ m, the HAPC concentrates ambient particle mass by approximately a factor of 28. It is logical that changes in particle CEF should be influenced by the amount of ambient particle mass within the concentrator's effective size range.

The concentrator operates optimally at a pressure drop of 2.5 in. of water per stage. Total pressure drop ranges from 7.5–25 in. of water, depending on the alignment of the slits of the virtual impactors and other parameters. Increases in the pressure drop result in decrease of the CEF, mainly due to excessive particle loss by impaction on the edges of the collection slit. In contrast, the minor operating pressure drop was found to be consistently lower on days where neither the ambient particle mass, temperature, or relative humidity were high. This subset of days was found to have a higher CEF than days where any of the three variables were high. The HAPC minor flow pressure drops are thus monitored carefully, since they are the most controllable indicator of concentration enrichment efficiency.     

Design of a Glass Impactor for an Annular Denuder/Filter Pack System

A glass impactor for an annular denuder/filter pack system was developed, to further the application of denuder technology in sampling atmospheric gases and particles. The glass impactor consists of an entrance section containing the inlet tube, the acceleration jet, and the impaction plate, which is mounted at the entrance to the annular denuder. The impaction plate is a removable porous glass disk which can be impregnated with mineral oil to minimize bounce-off of the collected particles during sampling. Calibration tests showed that the impactor has a 50% aerodynamic particle cutoff size of 2.1 μm, at a flow of 10 L min^?1. Particle loss experiments were conducted. Total losses on surfaces inside the impactor, annular denuder, and filter pack, determined for particle sizes ranging between 1.50 and 2.77 μm, were lower than 3%. Co-located air sampling was conducted using the glass impactor and the Harvard impactor. Mass concentrations determined using the Harvard impactor were about 10% higher than for the glass impactor because the glass impactor has a slightly lower aerodynamic particle cutoff point, while sulfate concentrations obtained from the two systems were in excellent agreement.     

A method for isolating adult and neonatal airway smooth muscle cells and measuring shortening velocity

Methods are described for isolating smooth muscle cells from the tracheae of adult and neonatal sheep and measuring the single-cell shortening velocity. Isolated cells were elongated, Ca2+ tolerant, and contracted rapidly and substantially when exposed to cholinergic agonists, KCl, serotonin, or caffeine. Adult cells were longer and wider than preterm cells. Mean cell length in 1.6 mM CaCl2 was 194 +/- 57 (SD) microm (n = 66) for adult cells and 93 +/- 32 microm (n = 20) for preterm cells (P < 0.05). Mean cell width at the widest point of the adult cells was 8.2 +/- 1.8 microm (n = 66) and 5.2 +/- 1.5 microm (n = 20) for preterm cells (P < 0.05). Cells were loaded into a perfusion dish maintained at 35 degreesC and exposed to agonists, and contractions were videotaped. Cell lengths were measured from 30 video frames and plotted as a function of time. Nonlinear fitting of cell length to an exponential model gave shortening velocities faster than most of those reported for airway smooth muscle tissues. For a sample of 10 adult and 10 preterm cells stimulated with 100 microM carbachol, mean (+/- SD) shortening velocity of the preterm cells was not different from that of the adult cells (0.64 +/- 0.30 vs. 0.54 +/- 0.27 s-1, respectively), but preterm cells shortened more than adult cells (68 +/- 12 vs. 55 +/- 11% of starting length, respectively; P < 0.05). The preparative and analytic methods described here are widely applicable to other smooth muscles and will allow contraction to be studied quantitatively at the single-cell level.     

Amorphous metals for hard-tissue prosthesis

Owing to a unique atomic structure lacking microstructural defects, glassy metals demonstrate certain universal properties that are attractive for load-bearing biomedical-implant applications. These include a superb strength, which gives rise to very high hardness and a potential for minimizing wear and associated adverse biological reactions, and a relatively low modulus, which enables high elasticity and holds a promise for mitigating stress shielding. There are, however, other non-universal properties specific to particular amorphous metal alloys that are inferior to presently used biometals and may be below acceptable limits for hard-tissue prosthesis. In this article, features of the performance of amorphous metals relevant to hard-tissue prosthesis are surveyed and contrasted to those of the current state of the art, and guidelines for development of new biocompatible amorphous metal alloys suitable for hard-tissue prosthesis are proposed.     

Children's sleep and school psychology practice.

Much contemporary research has demonstrated the multiple ways that sleep is important for child and adolescent development. This article reviews that research with an emphasis on how sleep parameters are related to school adjustment and achievement. Five areas of sleep research are reviewed to discern implications for practice with children using an evaluation rubric of strong, moderate, and weak evidence. The research has implications for assessment of sleep and sleepiness in the schools, for primary and secondary prevention activities, and for interventions by school psychologists targeting children and adolescents with sleep problems that affect their school functioning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)