An efficient algorithm for finding ideal schedules

We study the problem of scheduling unit execution time jobs with release dates and precedence constraints on two identical processors. We say that a schedule is ideal if it minimizes both maximum and total completion time simultaneously. We give an instance of the problem where the min-max completion time is exceeded in every preemptive schedule that minimizes total completion time for that instance, even if the precedence constraints form an intree. This proves that ideal schedules do not exist in general when preemptions are allowed. On the other hand, we prove that, when preemptions are not allowed, then ideal schedules do exist for general precedence constraints, and we provide an algorithm for finding ideal schedules in O(n ³) time, where n is the number of jobs. In finding such ideal schedules we resolve a conjecture of Baptiste and Timkovsky (Math. Methods Oper. Res. 60(1):145–153, 2004) Further, our algorithm for finding min-max completion-time schedules requires only O(n ³) time, while the most efficient solution to date has required O(n ⁹) time.     

Ethical decision making and psychologists' attitudes toward training in ethics.

Discusses the inadequacy of old, and the lack of new guidelines for the protection of the rights of individuals in psychological treatment. A questionnaire containing vignettes of clinical and research situations that required decision-making processes was completed by 113 members of the Division of Clinical Psychology of the American Psychological Association. Data suggest that there is inconsistency in decision making. Suggestions for improving the decision-making process and enhancing consistency are presented. (8 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Inducible amp C beta-lactamase producing gram-negative bacilli from blood stream infections: frequency, antimicrobial susceptibility, and molecular epidemiology in a national surveillance program (SCOPE)

A surveillance study of nosocomial blood stream infections [Surveillance and Control of Pathogens of Epidemiologic Importance (SCOPE)] was conducted during a 14-month period in 1995 to 1996 in approximately 50 American medical centers. Among the 4725 blood stream infections, the etiologic agent was Enterobacter spp. in 230, Citrobacter freundii in 24, and Serratia marcescens in 65. The vast majority of these isolates (89%) had been sent to the University of Iowa including 198 Enterobacter spp. (46 Enterobacter aerogenes, 141 Enterobacter cloacae, 11 other Enterobacter spp.), 23 C. freundii, and 62 S. marcescens. Because these species are capable of producing Amp C beta-lactamase, we examined their susceptibility to 12 broad-spectrum antimicrobial agents. The frequency of resistance to ceftazidime and the molecular epidemiology of ceftazidime-resistant strains was also examined. Among the Enterobacter spp. and C. freundii isolates, resistance to third generation cephalosporins (ceftazidime, ceftriaxone) and broad-spectrum semisynthetic penicillins (piperacillin), with or without an enzyme inhibitor (piperacillin/tazobactam), was high, e.g., 35 to 50%. The S. marcescens isolates were quite susceptible to all agents tested. Both imipenem and cefepime were active against virtually all isolates tested including 84 stably derepressed Amp C-producing ceftazidime-resistant strains of Enterobacter spp. and C. freundii. The overall rank order of activity for the six best agents against these Amp C-producing strains was: imipenem (100% susceptible) > amikacin = cefepime (98.6%) > ciprofloxacin = gentamicin = ofloxacin (93.6 to 94.0%). Molecular typing studies of ceftazidime-resistant E. cloacae using an automated ribotyping system, as well as pulsed-field gel electrophoresis, indicated that although clonal spread of a single strain occurred in some of the medical centers, most of the episodes of bacteremia were caused by patient-unique strains. Control of these resistant organisms will require attention to microbiologic recognition of phenotypes, to infection control practices, and to limiting the overuse of certain extended spectrum beta-lactams.     

Reliability and validity of the Parent-Child Relationship Inventory (PCRI): Evidence from a longitudinal cross-informant investigation.

Psychometric properties of the Parent-Child Relationship Inventory (PCRI) were examined using data collected from adolescents and their parents in the Fullerton Longitudinal Study. Results revealed acceptable internal consistency for most scales and moderate to high 1-year stability for all scales. Both parents' PCRI scores correlated with their views of family climate. Cross-informant concordance was pervasive and strong between mothers' PCRI scores and adolescents' perceptions of the parent-child relationship and family climate; however, convergence was not evident between fathers' and adolescents' reports. Additionally, poor performance was observed for the Autonomy scale. In conjunction with other research on parent-adolescent relationships, concerns are raised regarding the utility of scales to contrast mother-adolescent with father-adolescent relationships. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An approach to cost accounting and cost effectiveness in the delivery of campus mental health services.

A cost accounting system developed at the University of Texas Counseling Center is described, and a rationale for developing cost accounting systems in mental health is provided. The system is placed in the context of an evaluation model that has evolved at the University's counseling center. (4 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Characterization of glomerular thromboxane receptors in murine lupus nephritis

Renal thromboxane (Tx) production is increased in the MRL-lpr murine model of lupus nephritis. To investigate the relationship between increased Tx production and number and affinity of Tx receptors, we measured binding of the Tx receptor antagonist [3H][SQ295481S-1 alpha,2 beta(5Z),3 beta,4 alpha]-7-(3-((2-((phenyl- amino)-carbonyl)hydrozino)methyl)-7-oxabicyclo-(2.2.1)heptan -2-yl)-5-heptenoic acid in glomerular preparations from MRL-lpr mice and both MRL(-)+/+ and LG/J controls. Renal Tx binding was first characterized in normal LG/J mice. In these animals, glomerular binding was specific, saturable and reversible. Scatchard analysis revealed a single class of high-affinity binding sites. We next evaluated Tx production and binding in 12- and 16-week-old MRL-lpr mice and MRL(-)+/+ controls. To assess renal Tx production, excretion of TxB2 was measured in urine. Urinary TxB2 was increased in MRL-lpr mice at 16 weeks of age. This increase in urinary TxB2 was associated with a reduction in density of glomerular Tx binding sites compared to either 12-week-old MRL-lpr mice or MRL(-)+/+ controls. Ligand binding affinity was similar in all groups. To investigate if this alteration in binding was specific for Tx, glomerular binding of [3H]angiotensin II was measured. In MRL-lpr mice, the number and affinity of glomerular angiotensin binding sites were similar at 12 and 16 weeks of age. Thus, in this murine model of lupus nephritis, enhanced renal Tx production is temporally associated with a decrease in glomerular Tx binding sites without a change in receptor affinity.(ABSTRACT TRUNCATED AT 250 WORDS)     

Overview of graduate medical education. Funding streams, policy problems, and options for reform

In this article, we examine the financing mechanisms for graduate medical education (GME) in the United States. In so doing, we identify Medicare as the single largest contributor to GME and the most important barrier to producing a physician workforce that is appropriately sized, balanced, and skilled. Until passage of the 1997 Budget Reconciliation Agreement, the structure of Medicare payments promoted overproduction and skewed production toward training specialists in tertiary settings. We then examine the various reform proposals put forward by major health care organizations and policy bodies. These organizations generally agree on seven policy objectives: Remove incentives that promote expanded resident production; Base the GME subsidy on actual costs and distribute it more uniformly; Focus reductions on specialty residency positions; Provide GME payments for training provided in ambulatory, community, and managed care sites; Decouple Medicare GME reimbursement from payments to health maintenance organizations for patient care; Require all health insurers to contribute to GME; and Ensure that reductions in the GME subsidy do not reduce access to care for low-income persons. A myriad of different mechanisms for achieving these objectives have been recommended, many of which could be melded together to form a comprehensive approach to GME reform. The prospects for meaningful GME reform are dim in the absence of broader Medicare reform. The costs to stake-holders are too concentrated while the benefits to the public are too diffuse for GME reform to stand alone. But the political imperative to deal with the federal budget's short-term deficit and Medicare's long-term solvency will likely create an opportunity for GME reform. An addendum has been added that shows how the 1997 Budget Reconciliation Agreement addresses most of the major reform objectives identified but that several important issues remain unresolved.     

Independent practice association physician groups in California

Hemispatial neglect is a neurological disorder which entails a spatial bias that penalizes events occurring in the hemispace contralateral to a brain lesion. Mechanisms operating upon various stages ranging from perception to action have been invoked to explain neglect. The present study explores the contribution of a defective programming of arm movements towards the neglected hemispace to neglect behaviour. Two reaction time tasks -- a "perceptual" task and a "motor" task -- were performed by right brain-damaged (RBD) patients with left hemispatial neglect, RBD patients without signs of neglect and control subjects. The perceptual task consisted of lateralized visual stimuli and central motor responses, whereas the motor task consisted of visual stimuli presented on the vertical midline and hand responses to be produced in either hemispace. Neglect patients showed a rightward bias on the perceptual task, but only two RBD patients (showing no signs of severe neglect) were consistently slowed in producing leftward motor responses. Different reference frames may thus be used in perceptual tasks and tasks involving arm movements. We conclude that hemispatial neglect commonly results from attentional impairments operating upon a visual perceptual frame of reference; additional deficits appear to be necessary to produce a directional motor disorder.