Analysis of emptiness (lacunarity) as a measure of the degree of space filling and of the internal structure of a set

The study presents a comparative evaluation of emptiness (lacunarity) in model structures with different types of inhomogeneity of dispersed particle distributions. The research on emptiness (lacunarity) as a measure of the degree of space filling and, at the same time, of the internal characterization of a set has been based on the optimal covering and gliding-box methods.     

Insertion element IS3-based PCR method for subtyping Escherichia coli O157:H7

An Escherichia coli O157:H7 subtyping method based on PCR amplification of variable DNA sequences between the repetitive element IS3 was developed. Template DNA was prepared by boiling cells in Chelex. Two separate IS3 PCR amplifications were performed for each isolate: one with a single primer (primer IS3A) and one with two primers (primers IS3A and IS3B). The IS3 PCR subtyping method was applied to 35 epidemiologically related and unrelated E. coli O157:H7 isolates that had been previously characterized by pulsed-field gel electrophoresis (PFGE). PFGE identified 25 different subtypes (difference of one or more bands). PCR with single primer IS3A and primer pair IS3A-IS3B identified 6 and 14 different subtypes, respectively. By combining the results of the two PCR amplifications, 15 different IS3 PCR subtypes were identified. While not as sensitive as PFGE, IS3 PCR subtyping grouped all outbreak-related isolates. IS3 PCR banding patterns were reproducible between amplifications and between subcultures. IS3 PCR could serve as a simple, rapid screening method for the identification of unrelated E. coli O157:H7 isolates.     

Variations in personal space as a function of authoritarianism, self-esteem, and racial characteristics of a stimulus situation.

Investigated "personal space," the portable, flexible area surrounding an individual which has been viewed as a buffer zone between him and his environment. It was hypothesized that when 20 high and 20 low self-esteem and authoritarian white male undergraduates were approached by white and black male stimuli, (a) the largest areas of personal space would be used by high authoritarian, and low self-esteem ss; and (b) these ss would also use larger areas of personal space in response to the approach of the black stimulus than the white. The hypotheses are supported. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Calorimetric method for the determination of rates of emulsion polymerisation applied to methyl methacrylate

A small-scale calorimetric method developed for following the rate of polymerisation of monomers in solution and in bulk has now been adapted by construction of a stirred reaction vessel for the study of rates of emulsion polymerisation recipes. Results obtained for the emulsion polymerisation of methyl methacrylate are compared with those for polymerisation under bulk conditions.     

The antisteroid action on the pineal gland

The study presents the data gathered along the years on the antisteroid action of the pineal gland. Thus, it was demonstrated that administration of pineal polypeptides to the rabbit lowers the urinary 17-KS both of testicular and adrenal origin. Conversely, pinealectomy caused an increase in the level of these steroid hormones. The same pineal material induced a marked decrease both in the serum and testicular testosterone and in the plasma and adrenal corticosterone in the rat. At the same time administration of pineal polypeptides lowered the cholesterol in the serum, bile, liver, testis and adrenal. Melatonin had no effect on these biochemical indices, which demonstrates that the effects obtained with pineal polypeptides are not mediated by melatonin.     

Validating the use of channels to estimate the ideal linear observer

Image quality can be objectively defined according to how well an observer can perform a task of practical interest given the image. We review a practical model observer for the signal-detection task. The ideal observer for this task is a function of the image probability distributions, which are multidimensional and complicated. This observer is often too difficult to derive or estimate. An alternative to the ideal observer is the ideal linear observer, which can still be unmanageable. Our alternative is the ideal linear observer constrained to a small set of channels: the channelized-Hotelling observer.     

Updated Correlation Between Aircraft Smoke Number and Black Carbon Concentration

Aircraft emissions of black carbon (BC) contribute to anthropogenic climate forcing and degrade air quality. The smoke number (SN) is the current regulatory measure of aircraft particulate matter emissions and quantifies exhaust plume visibility. Several correlations between SN and the exhaust mass concentration of BC (C _BC) have been developed, based on measurements relevant to older aircraft engines. These form the basis of the current standard method used to estimate aircraft BC emissions (First Order Approximation version 3 [FOA3]) for the purposes of environmental impact analyses. In this study, BC with a geometric mean diameter (GMD) of 20, 30, and 60 nm and filter diameters of 19 and 35 mm are used to investigate the effect of particle size and sampling variability on SN measurements. For BC with 20 and 30 nm GMD, corresponding to BC emitted by modern aircraft engines, a smaller SN results from a given C _BC than is the case for BC with 60 nm GMD, which is more typical of older engines. An updated correlation between C _BC and SN that accounts for typical size of BC emitted by modern aircraft is proposed. An uncertainty of ±25% accounts for variation in GMD in the range 20–30 nm and for the range of filter diameters. The SN–C _BC correlation currently used in FOA3 underestimates by a factor of 2.5–3 for SN ≤15, implying that current estimates of aircraft BC emissions derived from SN are underestimated by the same factor.

Copyright 2013 American Association for Aerosol Research