A Generalized Approximation for the Thermophoretic Force on a Free-Molecular Particle

Particle size (30 to 10,000 nm) distributions in number concentration were measured using an Electrical Low Pressure Impactor onboard a Mobile Real-time Air Monitoring Platform from June 2002 to August 2003 in Hong Kong to investigate the size distributions of on-road vehicular particles and their relationship with ambient temperature (T) and relative humidity (RH). In this article, we focus on the size distributions of particles > 30 nm in vehicle plumes where fresh vehicular particles dominated and the NOx concentration was > 400 ppb. A uni-modal size distribution with mode at either 60–108 nm or 108–170 nm was generally observed from April to October. This mode is conventionally believed to be soot particles in the literature and the different mode sizes probably depend on engine and vehicle operating conditions. From November to March, a bi-modal size distribution with a dominant mode at 30–60 nm and a minor mode at either 108–170 nm or 60–108 nm was generally observed. The existence of the 30–60 nm mode is explained in the literature by the growth of nucleated particles when vehicular exhaust cools in ambient air. Ratios of the number concentration of 30–60 nm particles to BC mass concentration correlated negatively with T, as well as with RH when RH was < 60%. The ratios appeared not to be sensitive to RH when RH was > 60%. The correlations suggested that T and RH exert significant influences on the formation of vehicular submicron particles, leading to varying size distributions of vehicular particles in Hong Kong.     

An investigation of synesthesia.

This study was designed to investigate relations between synesthesia (the occurrence of imagery in one sense modality in response to sensations in another) and intellectual and personality functioning. Female (n?=?204) and male (n?=?170) subjects completed a visual-auditory synesthesia battery, paper-and-pencil synesthesia tests, the Multidimensional Personality Questionnaire (MPQ), and a brief intelligence test. The findings indicate generalized and continuously distributed individual differences in the tendency to represent sounds as colors in accordance with empirically derived norms. However, this ability is not related to individual differences in the reported vividness of the associated imagery or to intelligence. A moderate relation was found between vividness measures, particularly vividness of visual images associated with sound, and a tendency to enjoy and become involved in imaginative experiences as measured by the Absorption scale of the MPQ. Contrary to existing beliefs, vividness of synesthetic imagery was not found to be associated with personality dysfunction or with intelligence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comment on "Thermophoresis of a Near-Wall Particle at Great Knudsen Numbers"

An approximate expression for the thermophoretic force on a near-wall particle at large particle Knudsen number is presented. The wall has arbitrary specularity. The derivation of this expression follows that of Chen and Xu (2002) but corrects two errors in their approach. The corrected expression predicts that the near-wall thermophoretic force is only 5-10% greater than the bulk-gas (Waldmann) value and that the greatest difference occurs for a specular wall, whereas the original expression predicts that the force is increased up to 35% and that the greatest difference occurs for a diffuse wall. Independent molecular gas dynamics simulations confirm the corrected expression.     

Processing of logically valid and logically invalid conditional inferences in discourse comprehension.

Two competing theories of processing of conditionals (if-then) were tested. Syntactic theories posit that people only draw inferences conforming to the logically valid modus ponens (MP) schema. Mental models theories predict that people draw MP and invalid affirming-the-consequent (AC) inferences. Three experiments tested these predictions. Participants read short stories that conformed to either the MP or AC form but without conclusions, and they completed either priming or recognition tasks. Results indicate that both MP and AC inferences occur during discourse processing: MP and AC premise forms prime their respective conclusions, participants erroneously judged that they had read the conclusions to MP and AC arguments, and AC inferences did not stem from a biconditional interpretation of conditionals. Findings support mental models theories. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Increased formation of distinct F2 isoprostanes in hypercholesterolemia

BACKGROUND: F2 isoprostanes are stable, free radical-catalyzed products of arachidonic acid that reflect lipid peroxidation in vivo. METHODS AND RESULTS: Specific assays were developed by use of mass spectrometry for the F2 isoprostanes iPF2alpha-III and iPF2alpha-VI and arachidonic acid (AA). Urinary excretion of the 2 F2 isoprostanes was significantly increased in hypercholesterolemic patients, whereas substrate AA in urine did not differ between the groups. iPF2alpha-III (pmol/mmol creatinine) was elevated (P<0.0005) in homozygous familial hypercholesterolemic (HFH) patients (85+/-5. 5; n=38) compared with age- and sex-matched normocholesterolemic control subjects (58+/-4.2; n=38), as were levels of iPF2alpha-VI (281+/-22 versus 175+/-13; P<0.0005). Serum cholesterol correlated with urinary iPF2alpha-III (r=0.41; P<0.02) and iPF2alpha-VI (r=0. 39; P<0.03) in HFH patients. Urinary excretion of iPF2alpha-III (81+/-10 versus 59+/-4; P<0.05) and iPF2alpha-VI (195+/-18 versus 149+/-20; P<0.05) was also increased in moderately hypercholesterolemic subjects (n=24) compared with their controls. Urinary excretion of iPF2alpha-III and iPF2alpha-VI was correlated (r=0.57; P<0.0001; n=106). LDL iPF2alpha-III levels (ng/mg arachidonate) were elevated (P<0.01) in HFH patients (0.32+/-0.08) compared with controls (0.09+/-0.02). The concentrations of iPF2-III in LDL and urine were significantly correlated (r=0.42; P<0.05) in HFH patients. CONCLUSIONS: Asymptomatic patients with moderate and severe hypercholesterolemia have evidence of oxidant stress in vivo.     

An Implantable Blood Pressure and Flow Transmitter

A miniature totally implantable FM/FM telemetry system has been developed to simultaneously measure blood pressure and blood flow, thus providing an appreciation of the hemodynamics of the circulation to the entire body or to a particular organ. Developed for work with animal subjects, the telemetry system's transmission time is controlled by an RF signal that permits an operating life of several months.     

A simple and accurate high-pass filter and spectrometer using Huygen's principle

We have developed a new type of high pass filter and a new type of spectrometer. These devices are currently under testing and have yielded good agreement with theory. These devices seem to be easier to use and appear to be more accurate than devices now used.     

Psychological correlates of unwanted pregnancy.

Explored several psychological factors assumed, on the basis of clinical observation, to be related to undesired pregnancy because of failure to take contraceptive precautions. Differences in risk taking, use of denial as a defense, masochism, and sex guilt were explored among 3 groups of White college women: 33 who had voluntarily sought an abortion, 25 using medically prescribed contraceptive methods, and 26 unselected with regard to their sexual activity or contraceptive practices. Measures used included the Choice Dilemmas Questionnaire, Defense Mechanisms Inventory, and Mosher Forced-Choice Guilt Inventory. Significantly higher scores on scales reflecting use of denial and masochism were found in the abortion group, but no support was found for greater risk taking or sex guilt. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence of regulation on environmental conditions and the macroinvertebrate community in the upper Colorado river

The influence of stream regulation on environmental conditions and concomitant alterations of macroinvertebrate community structure was determined from field studies conducted from September 1981-June 1983 at three sites on the upper Colorado River. Site 1 (reference site) was located above Granby and Shadow Mountain Reservoirs, a deep-release storage impoundment, whereas sites 2 (regulated site) and 3 (recovery site) were located 0·4 and 4·0 km, respectively, below the dam. Although macroinvertebrate diversity was reduced at the regulated site compared to both the reference and recovery sites, the number of taxa (43) was considerably higher than values reported from studies of other regulated streams in the Rocky Mountains. Macroinvertebrate mean annual density in the regulated site was twenty times higher than at the reference site and slightly higher than the recovery site. The regulated site was characterized by the absence of heptageniid mayflies, reductions in stoneflies, caddisflies, shredders, and predators, and high densities of Baetis spp., Ephemerella infrequens, chironomids, and non-insect taxa. Many of these faunal changes are attributed to alterations in the temperature regime induced by regulation and to changes in the source and temporal sequencing of organic detritus. Although the number of annual degree days was actually greater below the dam than above the reservoir, other components of the thermal regime was severely altered by regulation. At the regulated site the primary source of coarse organic detritus was autochthonous (decaying algae) with a vernal pulse, in contrast to the typical autumnal pulse of allochthonous leaf litter. There was no evidence that the greater substrate permeability and flow predictability below the dam directly influenced the reduction of species.