Precipitous weakening of quartz at the α–β phase inversion

Crystalline quartz has long been identified as among the weakest of abundant crustal minerals. This weakness is particularly evident around the α–β phase inversion at 573°C, in which Si–O bonds undergo a displacive structural transformation from trigonal to hexagonal symmetry. Here we present data using indentation testing methodologies that highlight the precipitous extent of the transformational weakening. Although the indentations are localized over relatively small specimen contact areas, the data quantify the essential deformation and fracture properties of quartz in a predominantly (but not exclusively) compressive stress field, at temperatures and pressures pertinent to conditions in the earth's crust.     

A New Measure of Misfit for Covariance Structure Models

Various fit indices exist in structural equation models. Most of these indices are related to the noncentrality parameter (NCP) of the chi-square distribution that the involved test statistic is implicitly assumed to follow. Existing literature suggests that few statistics can be well approximated by chi-square distributions. The meaning of the NCP is not clear when the behavior of the statistic cannot be described by a chi-square distribution. In this paper we define a new measure of model misfit (MMM) as the difference between the expected values of a statistic under the alternative and null hypotheses. This definition does not need to assume that the population covariance matrix is in the vicinity of the proposed model, nor does it need for the test statistic to follow any distribution of a known form. The MMM does not necessarily equal the discrepancy between the model and the population covariance matrix as has been assumed in existing literature. Bootstrap approaches to estimating the MMM and a related quantity are developed. An algorithm for obtaining bootstrap confidence intervals of the MMM is constructed. Examples with practical data sets contrast several measures of model misfit. The quantile-quantile plot is used to illustrate the unrealistic nature of chi-square distribution assumptions under either the null or an alternative hypothesis in practice.

     

Self-monitoring and intake interviewers' therapeutic orientations.

A therapist's theoretical orientation is likely to influence every facet of the therapeutic process. We explore the relationship of therapeutic orientation and self-monitoring style. To test the hypothesis that high self-monitors would be more eclectic than low self-monitors, we surveyed 30 intake therapists at a child guidance center. Results supported the hypothesis; those frequently using more than one orientation had higher self-monitoring scores. Furthermore, self-monitoring correlated negatively with psychoanalytic endorsement, but in a positive direction with behavioral, systems and eclectic endorsements. Results are discussed in terms of training needs of those differing in self-monitoring style. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Extended donor criteria: use of cardiac allografts after carbon monoxide poisoning

BACKGROUND: An increasing demand for cardiac allografts for the treatment of end-stage cardiac failure has led to a shift in the traditional views about donor criteria. The use of allografts exposed to high concentrations of carbon monoxide is still under discussion. The current literature on this topic is contradictory. We describe our experience with orthotopic cardiac transplantation, using cardiac allografts after carbon monoxide poisoning. METHODS: Between March 13, 1989 and August 1, 1996, 770 orthotopic heart transplantations were performed in our center. Within this period, we accepted five cardiac allografts from brain-dead, carbon monoxide-poisoned donors. Donor history showed carbon monoxide intoxication in all cases. At the time of organ explantation, donor hemodynamic parameters were feeble in all patients. RESULTS: The postoperative course was uneventful in three of the five recipients. The overall 3-year survival rate in this small group is 40%. Induction therapy or rescue therapy with mono/polyclonal antibodies was not necessary. Myocardial right-ventricular biopsies did not show any specific signs of carbon monoxide poisoning. CONCLUSIONS: In our opinion, cardiac allografts from donors exposed to carbon monoxide can be transplanted successfully in infants and adults, if there are no signs of severe hemodynamic dysfunction in the presence of a normal central venous pressure and low-dose support with catecholamines and there are no electrocardiographic changes in combination with elevated transaminase. With extended donor criteria, the hearts of carbon monoxide-poisoned victims could increase the number of suitable organs and lower the death rate of patients on the United Network for Organ Sharing and Eurotransplant International Foundation waiting lists.     

Effect of shigella enterotoxin 1 (ShET1) on rabbit intestine in vitro and in vivo

The purpose of this study was to identify the optimal knot construction for interrupted dermal sutures. A synthetic braided absorbable suture, sizes 3-0 and 5-0, was selected for this evaluation. With reproducible mechanical performance tests, we determined that the construction of secure knots without ears required one additional throw as compared with secure knots with 3-mm ears. The direction of applied tension did not alter knot security, with the exception of granny knots, which required an extra throw when tension was applied parallel to the suture loop. Because interrupted dermal knot construction is accomplished without knot ears and with an applied tension parallel to the wound, one additional throw must be added to the knot to ensure knot security.     

Construction of recombination-deficient strains of Streptococcus gordonii by disruption of the recA gene

Degenerate oligonucleotide primers were used in a polymerase chain reaction (PCR) to amplify a region of the recA sequence of Streptococcus gordonii Challis. The resulting PCR fragment was cloned into the suicide vector pAM6199 and introduced into strain Challis, giving rise to recombination-deficient strains in which the recA gene was specifically inactivated.