Wind tunnel modelling as a means of predicting the response of chimmeys to vortex shedding

The limitations of wind tunnel testins, particularly for chimneys with a circular cross-section are discussed. The use of data from full-scale observations and wind tunnel tests at high Reynolds numbers in conjunction with suitable mathematical models are suggested to obtain wind load and wind response estimates that offer a higher level of reliability than wind tunnel estimates.     

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.     

Professionals in mutual help groups: Impact on social climate and members' behavior.

This study assessed the impact of professional involvement in mutual help groups for the mentally ill. Social climate data and behavioral data on members in groups led either by a mental health professional (n?=?36) or an indigenous group member (n?=?70) were compared. The results of the study indicated a more formal, psychologically directed approach in the professionally led groups. Although professional involvement in mutual help groups does not necessarily produce different member outcomes, it does seem to affect both the perceptions and the behavior of members. Professionals should be cautious when they get involved in mutual help groups to avoid professionalizing them. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Protective effect of cysteine and vitamin E, Crocus sativus and Nigella sativa extracts on cisplatin-induced toxicity in rats

There are three ways to approach and resect the caudate lobe of the liver, that is; and isolated caudate lobectomy, a combined resection of the liver overlying the caudate lobe, and a transhepatic anterior approach by splitting parenchyma of the liver. We had two patients with neoplasms originating in the caudate lobe who underwent a complete caudate lobectomy. Both patients have been doing well without liver dysfunction. Although after the transhepatic anterior approach we anticipated an adverse effect from splitting the parenchyma of the liver, the postoperative course was uneventful and similar to that of the right side approach.     

Mathematical approximation techniques in biophysical models

The mathematical characterization of biophysical problems often leads to certain transcendental functions which must be evaluated to fully appreciate the significance of the mathematical model. In illustration, many mathematical models concerned with wave propagation and transmission of fluids through elastic tubes require treatment of the various kinds of Bessel functions and their ratios. In my recent work (The Special Functions and Their Approximations, Volumes 1 and 2, Academic Press, 1969) polynomial, rational and infinite series expansions in series of Chebyshev polynomials are developed for a wide class of transcendental functions which include Bessel functions as special cases. In numerous instances, tables of coefficients are presented. In the present paper, we show how these ideas can be exploited to yield economic methods for the evaluation of Bessel functions arising in the problems cited. As the approximations can be given in closed form, they can be easily applied to further simplify available closed form analyses.     

Influence of thermophysical properties on pool boiling heat transfer of refrigerants

The correct prediction of the heat transfer performance of the boiling liquid within the evaporator of a refrigeration unit is one of the essential features for the successful operation of the whole unit. A theoretically consistent calculation method for the heat transfer coefficient α in nucleate boiling, which should be based on the physical phenomena connected with vapour bubbles growing, departing and sliding on the wall and with the interactions of bubbles and of neighbouring nucleation sites within the microstructure of the heating surface, does not yet exist, despite the increasing number of papers on the subject in the recent past. Instead, the predictive methods for α available at present are empirical or semiempirical, especially for heat transfer conditions relevant in practice. Many of these correlations have been established in the form of power laws in which the relative influences of the main groups of variables on α are treated by separate factors. One of these may stand for the influence of the thermophysical properties of the boiling liquid or these properties will be included in several of the factors.New experimental results are presented for pool boiling heat transfer from a single horizontal copper tube (8 mm OD) to HFC-refrigerants (R32, 125, 134a, 143a, 152a, 227ea) and hydrocarbons (propane, i-butane). The results are compared to experimental data from the literature, and methods are discussed, how to incorporate the data in semiempirical correlations to describe the influence of the thermophysical properties of the fluids on the heat transfer performance.     

Dissemination of central nervous system tissue from the brain and spinal cord of cattle after captive bolt stunning and carcass splitting

In the absence of reliable live animal tests for the presence of BSE in cattle, a number of measures have been applied to exclude specified risk materials (SRM) from the human food chain. However, concerns remain that current practices in the stunning and slaughter of cattle may disseminate central nervous system (CNS) tissue to meat and meat contact surfaces. The objective of this study was to establish the particular risks of CNS tissue dissemination associated with captive bolt stunning and carcass splitting. The study applied enzyme linked immunosorbent assays (ELISAs) in the detection and quantification of two CNS proteins, syntaxin 1b and GFAP. The study observed extensive dispersal of both CNS proteins onto equipment, beef hide and personnel. These results demonstrate that despite the rigorous application of current SRM control policies, normal slaughter practices continue to present significant opportunities for CNS material including BSE prion present in the CNS of any sub-clinically infected cattle to contaminate meat entering the human food chain.     

Modification point depth and genome growth in genetic programming

The evolutionary computation community has shown increasing interest in arbitrary-length representations, particularly in the field of genetic programming. A serious stumbling block to the scalability of such representations has been bloat: uncontrolled genome growth during an evolutionary run. Bloat appears across the evolutionary computation spectrum, but genetic programming has given it by far the most attention. Most genetic programming models explain this phenomenon as a result of the growth of introns, areas in an individual which serve no functional purpose. This paper presents evidence which directly contradicts intron theories as applied to tree-based genetic programming. The paper then uses data drawn from this evidence to propose a new model of genome growth. In this model, bloat in genetic programming is a function of the mean depth of the modification (crossover or mutation) point. Points far from the root are correspondingly less likely to hurt the child's survivability in the next generation. The modification point is in turn strongly correlated to average parent tree size and to removed subtree size, both of which are directly linked to the size of the resulting child.