On finding optimal and near-optimal lineal spanning trees

The search for good lineal, or depth-first, spanning trees is an important aspect in the implementation of a wide assortment of graph algorithms. We consider the complexity of findingoptimal lineal spanning trees under various notions of optimality. In particular, we show that several natural problems, such as constructing a shortest or a tallest lineal tree, are NP-hard. We also address the issue of polynomial-time, near-optimization strategies for these difficult problems, showing that efficient absolute approximation algorithms cannot exist unlessP = NP.This author's research was supported in part by the Sandia University Research Program and by the National Science Foundation under Grant M IP-8603879.This author's research was supported in part by the National Science Foundation under Grants ECS-8403859 and MIP-8603879.     

Normative data for the Wechsler Memory Scale—Revised: 25- to 34-year olds.

The normative data provided in the Wechsler Memory Scale—Revised (WMS—R) manual for individuals aged 25–34 yrs were estimated statistically by interpolation. As an empirical check of this procedure, a representative stratified sample in this age range was selected to match the 1980 US Census data on relevant demographic characteristics. Prorated Full Scale IQs for the group were normally distributed, having a mean of 101.3 (SD?=?14.58, range?=?72–231). Differences between the empirically derived and published index scores appeared to be clinically significant. Substantial intra-individual differences were common when Visual–Verbal or General–Attention/Concentration indexes were compared. Normative data for the WMS—R subtests, indexes, and distribution of differences between indexes is provided. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The contrast enhancement of brain and spinal cord tumors using Gd-DTPA in magnetic resonance tomography with an extra-low magnetic-field intensity

The contrasting agent Gd-DTPA (Magnevist, Schering AG, Germany) was tested when used in magnetic resonance tomography using extra-low (0.04 T) magnetic field intensity in 68 patients with various brain and spine tumors. The agent was injected intravenously in a dose of 0.1 mmol/kg. No complications were found. The tests showed its high efficiency in the diagnosis of brain neoplasms (particularly in malignant intracerebral disorders, meningiomas and neurinomas). Benign astrocytomas induced no noticeable signal intensification on post-contrasting T1-weighed tomograms. In all cases of spinal tumors, the application of Gd-DTPA could specify the extent of tumor invasions, the presence of cysts and identify accessory tumor nodes in one case.     

Value of the monitoring of curarisation during prolonged mivacurium induced neuromuscular block

A case of neuromuscular blockade of about 200 min of duration, in a 9-year-old boy from mivacurium 0.15 mg.kg-1 is reported. The diagnosis was delayed, after onset of the first signs of recovery, due to the lack of monitoring of neuromuscular transmission. The neuromuscular blockade was reversed with neostigmine 0.04 mg.kg-1. Complete reversal required fifty minutes. The presence of an abnormal genetic variant of pseudocholinesterases was demonstrated by the measurements of pseudocholinesterase activity and dibucaine number. The importance of monitoring of neuromuscular transmission for diagnosis and treatment of mivacurium-induced neuromuscular blockade is underlined.     

The reflective educator.

Since the Boulder conference on training in clinical psychology in 1949, at least 13 national conferences have been convened to examine issues in training for practice in psychology, all based on the assumption that extensive training is required to develop professional skills in psychotherapy, psychodiagnosis, and related professional functions. This assumption is challenged by a large body of research that fails to show any relationship between training and efficacy in common forms of practice. Educators of professional psychologists are urged to heed the challenge closely and examine its implications critically. At the same time, educators of researchers in psychology are encouraged to examine common assumptions about the nature of practice in psychology and to consider conceptions of professional work that emphasize reflection in action and disciplined inquiry, rather than psychotherapy and psychodiagnosis, as defining features. Education for practice is neither science nor art, but a profession in itself. When the educational process is approached from this vantage point, novel opportunities for systematic investigation emerge. Decisive studies of the appropriate kind have yet to be done. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Introduction.

This article introduces the current issue of Health Psychology. The call for early intervention to prevent adulthood health problems and the need to consider each period of children's lives within its developmental perspective are the main emphases in this special issue of the journal. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Recent developments in the synthesis and discovery of oligosaccharides and glycoconjugates for the treatment of disease

The development of the first automated oligosaccharide synthesizer, along with new methods for screening carbohydrate ligand arrays is likely to lead to a rapid acceleration in both our ability to synthesize these molecules, and understand the roles of oligosaccharides and glycoconjugates in biology. Consequently we may uncover new avenues for therapeutic intervention more rapidly. These recent developments are very important since our understanding of the role of glycoconjugates in nature has traditionally fallen far behind that of the other biopolymers such as proteins and nucleic acids as the formation of, for example, glycosylated proteins is not template driven. The chemical synthesis of oligosaccharides and glycoconjugates has provided us with new potential cancer vaccines, antibiotics and new biotechnological tools. Glycobiologists have employed many such tools to uncover new signalling roles for oligosaccharides and glycoconjugates. In this review we aim to highlight some emerging methods for glycoconjugate assembly and screening, and discuss innovative approaches to glycoconjugate based drug design and delivery, all of which are, and will continue to be, fruitful avenues for medicinal chemistry research.     

Master sintering curve concepts as applied to the sintering of molybdenum

Sintering experiments with various molybdenum powders are rationalized using a master sintering curve concept that collapses density, grain size, or other parameters onto a single curve. In this case, the integral work of sintering is developed and customized for different green densities. Construction of the master sintering curve is described to show how the curve can be normalized with respect to green density effects. Various grades of molybdenum for metal injection molding and die compaction are included in the analysis, processed over a range of heating cycles. Die-compacted samples of varying green densities are used to illustrate the efficacy of the new, normalized master sintering curve concept. Sintering cycle optimization is one possible outcome from this analysis.