Showing papers by "University of Wisconsin–Milwaukee published in 1998"

Gravitational Radiation Instability in Hot Young Neutron Stars

Abstract: We show that gravitational radiation drives an instability in hot young rapidly rotating neutron stars. This instability occurs primarily in the l=2 r-mode and will carry away most of the angular momentum of a rapidly rotating star by gravitational radiation. On the timescale needed to cool a young neutron star to about T=10^9 K (about one year) this instability can reduce the rotation rate of a rapidly rotating star to about 0.076\Omega_K, where \Omega_K is the Keplerian angular velocity where mass shedding occurs. In older colder neutron stars this instability is suppressed by viscous effects, allowing older stars to be spun up by accretion to larger angular velocities.

Axial instability of rotating relativistic stars

Abstract: Perturbations of rotating relativistic stars can be classified by their behavior under parity. For axial perturbations (r-modes), initial data with negative canonical energy is found with angular dependence eim for all values of m ≥ 2 and for arbitrarily slow rotation. This implies instability (or marginal stability) of such perturbations for rotating perfect fluids. This low m-instability is strikingly different from the instability to polar perturbations, which sets in first for large values of m. The timescale for the axial instability appears, for small angular velocity Ω, to be proportional to a high power of Ω. As in the case of polar modes, viscosity will again presumably enforce stability except for hot, rapidly rotating neutron stars. This work complements Andersson's numerical investigation of axial modes in slowly rotating stars.

Green-wave phenology

Abstract: Phenology, the traditional study of seasonal plant and animal activity driven by environmental factors, has found new relevance in research into global climate change1,2,3,4 Global phenology research so far has concentrated on measurements obtained by satellites, downplaying connections of these measures to information obtained on the surface1,4, perhaps because of a lack of conventional, surface-based phenological data However, an integration of conventional and satellite-derived measures is needed to understand better the mid-latitude spring onset of photosynthesis, known as the ‘green wave’ or ‘green-up’5,6,7 Here I show how a surface-based green-wave model can extend the monitoring of climatic variability back to 1900, providing a longer-term context for the more limited, recent data obtained from satellites

Phagotrophy by a flagellate selects for colonial prey: A possible origin of multicellularity

Abstract: Summary Predation was a powerful selective force promoting increased morphological complexity in a unicellular prey held in constant environmental conditions. The green alga, Chlorella vulgaris, is a well-studied eukaryote, which has retained its normal unicellular form in cultures in our laboratories for thousands of generations. For the experiments reported here, steady-state unicellular C. vulgaris continuous cultures were inoculated with the predator Ochromonas vallescia, a phagotrophic flagellated protist (‘flagellate’). Within less than 100 generations of the prey, a multicellular Chlorella growth form became dominant in the culture (subsequently repeated in other cultures). The prey Chlorella first formed globose clusters of tens to hundreds of cells. After about 10‐20 generations in the presence of the phagotroph, eight-celled colonies predominated. These colonies retained the eight-celled form indefinitely in continuous culture and when plated onto agar. These selfreplicating, stable colonies were virtually immune to predation by the flagellate, but small enough that each Chlorella cell was exposed directly to the nutrient medium.

Success of data resource management in distributed environments: an empirical investigation

Abstract: The trend toward distributed processing has significantly increased the awareness of data as a key corporate resource and underscored the importance of its management. In spite of this, there is a lack of empirical investigation of issues related to data resource management (DRM) in distributed processing environments. Being perhaps the first empirical attempt, this exploratory study identifies four information systems (IS) variables related to DRM in a distributed environment. It also seeks to examine the notion of gestalt fit to describe the nature of the relationships among these variables. In addition, the study evaluates whether intemally congruent groups outperform their opposites in realizing DRM success. The results of cluster analysis support the view of gestalt fit by identifying five clusters. The results also suggest that organizations represented by a well-blended configuration of high intersite data dependence, high centralization of IS decisions, high concentration IS resources at the central site, and low DRM-related autonomy granted to local sites appear to realize a greater degree of DRM success than the other groups. The implications of the study are discussed, and further research directions are proposed.

A Critical Review of Functional Capacity Evaluations

Abstract: The role of functional capacity evaluations (FCEs) appears to be increasing as employers and insurers rely more heavily on them for decision making. To meet credibility requirements, and the American Physical Therapy Association's standards for measurement and documentation, all FCE suppliers need to validate and refine their systems. This article provides information that can be used to make informed decisions in the selection of an FCE and in functional assessment practices. Features of well-designed FCEs are discussed. Ten well-known FCE systems are analyzed according to these features and other common characteristics. Current issues such as the qualifications of the evaluators, reliability and validity, length of assessments, projection of endurance to 8-hour workdays, standards of practice, safety protocols, and behavioral assessment and management strategies are discussed.

Teachers for multicultural schools: The power of selection

Abstract: (1998). Teachers for multicultural schools: The power of selection. Theory Into Practice: Vol. 37, Preparing Teachers for Cultural Diversity, pp. 96-104.

Modeling the Conditional Probability of Foreclosure in the Context of Single‐Family Mortgage Default Resolutions

Abstract: Both empirical and pricing-simulation models of mortgage default focus on foreclosure in a one-step decision framework. Such models are misspecified to the extent that mortgage default and foreclosure are two separate decisions or events, where foreclosure is but one outcome of a default episode. This study examines the dynamics of mortgage borrower default episodes using a large sample of FHA-insured single-family mortgages. We estimate the influence of borrower characteristics, mortgage terms, and economic conditions on probabilities of various resolutions, highlighting under what conditions foreclosure is more likely to result from mortgage default.

Insights of nurses about assault in hospital-based emergency departments

Abstract: PURPOSE: To explore contributing factors, consequences, and solutions to the assault of nurses working in U.S. hospital emergency departments. This preliminary study targeted emergency nurses whose risk for assault was significantly greater than many other workers. Exploring nurses' opinions about factors they believe contribute to assault provides important information for designing acceptable preventive measures. DESIGN: In this descriptive study, an ecological, occupational-health framework was used which integrates personal, organizational, and societal influences. The six components of the framework were personal factors, workplace factors, environmental factors, assault injuries, solutions, and effects of workplace violence. METHOD: Four focus groups were used comprised of 22 RNs employed in emergency departments in one large metropolitan area in the United States. Half the nurses had been physically assaulted at work. FINDINGS: Fourteen themes emerged: nurse attitude, vulnerability, security, administrative issues, assault reporting, safety training, beyond control, societal changes, types of patients, geographic location, pervasiveness of anger, previous assault experiences, effects and possible solutions. Personal, workplace, and environmental factors all contribute to assault. Verbal and physical assaults are common and affect nurses' personal and professional lives. CONCLUSIONS: Assault-related injuries are preventable. Only physical injuries are treated; all employees who have been verbally or physically assaulted should be referred for post-incident debriefing. Hospital managers should implement violence-prevention programs. The ecological, occupational health framework is useful for identifying factors that contribute to assault. Language: en

Pressure infiltration technique for synthesis of aluminum–fly ash particulate composite

Abstract: Beds of nickel coated and uncoated cenosphere fly ash can be successfully infiltrated by molten aluminum under very low pressures. The density of the resultant composite is ≈1.4 and 1.2 g cm−3 respectively, compared to 2.68 g cm−3, the density for aluminum. The threshold pressure was found to be between 20.68 and 27.58 kPa for infiltration of molten pure aluminum into uncoated fly ash, and around 6.7 kPa for Ni-coated fly ash. These data were used to back calculate an effective wetting angle between molten pure aluminum and fly ash using Young’s and Washburn equations. The average value of the wetting angle calculated for uncoated fly ash is 111°. The microstructures and chemical composition of the composites made with coated and uncoated fly ash were studied using optical and scanning microscopy; they show good infiltration except for regions between contacting cenospheres. They also show transport of nickel from the bottom to the top of the sample when nickel coated particles were used.

Shewanella amazonensis sp. nov., a novel metal-reducing facultative anaerobe from Amazonian shelf muds

Abstract: A new bacterial species belonging to the genus Shewanella is described on the basis of phenotypic characterization and sequence analysis of its 16S rRNA-encoding and gyrase B (gyrB) genes. This organism, isolated from shallow-water marine sediments derived from the Amazon River delta, is a Gram-negative, motile, polarly flagellated, facultatively anaerobic, rod-shaped eubacterium and has a G&C content of 51.7 mol%. Strain SB2BT is exceptionally active in the anaerobic reduction of iron, manganese and sulfur compounds. SB2BT grows optimally at 35 degrees C, with 1-3% NaCl and over a pH range of 7-8. Analysis of the 16S rDNA sequence revealed a clear affiliation between strain SB2BT and members of the gamma subclass of the class Proteobacteria. High similarity values were found with certain members of the genus Shewanella, especially with Shewanella putrefaciens, and this was supported by cellular fatty acid profiles and phenotypic characterization. DNA-DNA hybridization between strain SB2BT and its phylogenetically closest relatives revealed low similarity values (24.6-42.7%) which indicated species status for strain SB2BT. That SB2BT represents a distinct bacterial species within the genus Shewanella is also supported by gyrB sequence analysis. Considering the source of the isolate, the name Shewanella amazonensis sp. nov. is proposed and strain SB2BT (= ATCC 700329T) is designated as the type strain.

V˙o 2 max is associated with ACE genotype in postmenopausal women

Abstract: Relationships have frequently been found between angiotensin-converting enzyme (ACE) genotype and various pathological and physiological cardiovascular outcomes and functions. Thus we sought to det...

Construction of highly accurate models of rotating neutron stars: Comparison of three different numerical schemes

Abstract: We conduct a direct comparison of three dier- ent representative numerical codes for constructing mod- els of rapidly rotating neutron stars in general relativity. Our aim is to evaluate the accuracy of the codes and to investigate how the accuracy is aected by the choice of interpolation, domain of integration and equation of state. In all three codes, the same physical parameters, equations of state and interpolation method are used. We construct 25 selected models for polytropic equations of state and 22 models with realistic neutron star matter equations of state. The three codes agree well with each other (typical agreement is better than 0.1% to 0.01%) for most mod- els, except for the extreme assumption of uniform density stars. We conclude that the codes can be used for the con- struction of highly accurate initial data congurations for polytropes of index N> 0 :5 (which typically correspond to realistic neutron stars), when the domain of integra- tion includes all space and for realistic equations with no phase transitions. With the exception of the uniform den- sity case, the obtained values of physical parameters for the models considered in this paper can be regarded as \standard" and we display them in detail for all models.

Cointegration Approach to Estimate the Long-Run Trade Elasticities in LDCs

Abstract: The Marshall-Lerner condition postulates that if the sum of import and export demand elasticities add up to more than one, devaluation should improve the trade balance in the long-run. This paper is the first to employ a long-run method, i.e., cointegration technique to estimate trade elasticities in less develop countries. In most cases the results reveal that indeed trade elasticities are large enough to support devaluation as a successful policy to improve the trade balance. [F10, F31]

Some Ideological Foundations of Organizational Downsizing

Abstract: This article explores the ideological foundations of organizational downsizing in the 1990s and focuses on the ideology of employee self-reliance and the ideology of debureaucratization. We document these two managerial ideologies by examining business press articles and popular management literature in which they are being promulgated. Based on past organizational research that has traced the effects of ideologies on organizations, we argue that these two ideologies increase the likelihood of downsizing. This theoretical framework is developed, and its implications for future research, management practice, and government policy are discussed.

Predictors of health-related quality of life with cardiac rehabilitation after acute myocardial infarction.

Abstract: Background Health-related quality of life (HRQL) instruments provide valid and responsive outcome measures to assess the impact of disease and the response to interventions. However, they have not been applied widely to studies of rehabilitation after myocardial infarction. Purpose To examine the extent to which baseline sociodemographic and clinical characteristics predict baseline and change in generic and specific HRQL. Methods A randomized controlled trial of an 8-week cardiac rehabilitation intervention or usual care, with follow-up for 12 months, in 201 patients with acute myocardial infarction (MI). Multiple regression analysis was used to identify predictors of HRQL. Results Specific HRQL scores and exercise tolerance improved significantly more in rehabilitation patients than usual care patients by the end of the 8-week intervention. All HRQL measures and exercise tolerance in both groups improved significantly during the 12 month follow-up period but the differences between the groups were trivial. A poor baseline HRQL was the predominant predictor of improved generic and specific HRQL. Furthermore, greater improvement in HRQL consistently was associated with lower levels of cardiovascular risks such as absence of a previous MI or coronary artery bypass surgery, absence of angina, less smoking, and higher exercise tolerance. Conclusions Improved generic and specific HRQL was associated with poorer baseline HRQL and less baseline cardiovascular risk. This reinforces the importance of addressing health behavior changes as soon as possible after MI and the usefulness of assessing both generic and specific HRQL in evaluating treatment effectiveness.

The limits of postmodernism in accounting history: The Decatur experience

Abstract: This paper presents a response to Miller and O'Leary's (1994) study of the factory modernization at Caterpillar's Decatur plant and the role of accounting and other expertises in constituting subjectivities. The research draws extensively from interviews with workers in Caterpillar's Decatur plant to develop a defense of historical materialism against postmodern interpretations of managerial accounting practices that abandon the concepts of class, ideology, and social structure.

The Mechanistic Structure Shift and Strategic Reorientation in Declining Firms Attempting Turnarounds

Abstract: Past researchers have observed that declining organizations often experience mechanistic structural changes that centralize authority, increase reliance on formalized procedures, and reduce the amount of information flowing to top managers. Many have proposed that this "mechanistic shift" in declining organizations reduces their adaptive capability by making innovative organizational change in response to decline less likely. However, despite much research on declining firms and their turnaround attempts, many questions about mechanistic shifts remain, such as: (1) To what extent do declining firms become systematically mechanistic when trying to recover from decline? (2) What aspects of declining firms' situations make mechanistic shifts more likely? (3) Do mechanistic shifts reduce the likelihood of large-scale strategic reorientation as declining firms attempt to recover? We sought answers to these questions through an analysis of data from in-depth interviews with top managers (mostly CEOs) at 29 U.S....