bluuebunny/crossref_metadata_2025 huggingface dataset:
Datapath and control for quantum wires
Authors: Isailovic Nemanja , Whitney Mark , Patel Yatish , Kubiatowicz John , Copsey Dean , Chong Frederic T. , Chuang Isaac L. , Oskin Mark
Published: August 2005

As quantum computing moves closer to reality the need for basic architectural studies becomes more pressing. Quantum wires, which transport quantum data, will be a fundamental component in all anticipated silicon quantum architectures. Since they cannot consist of a stream of electrons, as in the classical case, quantum wires must fundamentally be designed differently. In this paper, we present two quantum wire designs: a swap wire, based on swapping of adjacent qubits, and a teleportation wire, based on the quantum teleportation primitive. We characterize the latency and bandwidth of these two alternatives in a device-independent way. Furthermore, unlike classical wires, quantum wires need control signals in order to operate. We explore the complexity of the control mechanisms and the fundamental tension between the scale of quantum effects and the scale of the classical logic needed to control them. This "pitch-matching" problem imposes constraints on minimum wire lengths and wire intersections, leading us to use a SIMD approach for the control mechanisms. We ultimately show that qubit decoherence imposes a basic limit on the maximum communication distance of the swapping wire, while relatively large overhead imposes a basic limit on the minimum communication distance of the teleportation wire.
TRIPS
Authors: Sankaralingam Karthikeyan , Nagarajan Ramadass , Liu Haiming , Kim Changkyu , Huh Jaehyuk , Ranganathan Nitya , Burger Doug , Keckler Stephen W. , McDonald Robert G. , Moore Charles R.
Published: August 2005

This paper describes the
polymorphous
TRIPS architecture that can be configured for different granularities and types of parallelism. The TRIPS architecture is the first in a class of post-RISC, dataflow-like instruction sets called explicit data-graph execution (EDGE). This EDGE ISA is coupled with hardware mechanisms that enable the processing cores and the on-chip memory system to be configured and combined in different modes for instruction, data, or thread-level parallelism. To adapt to small and large-grain concurrency, the TRIPS architecture prototype contains two out-of-order, 16-wide-issue grid processor cores, which can be partitioned when easily extractable fine-grained parallelism exists. This approach to polymorphism provides better performance across a wide range of application types than an approach in which many small processors are aggregated to run workloads with irregular parallelism. Our results show that high performance can be obtained in each of the three modes---ILP, TLP, and DLP---demonstrating the viability of the polymorphous coarse-grained approach for future microprocessors.
Use of the Zebrafish System to Study Primitive and Definitive Hematopoiesis
Authors: de Jong Jill L.O. , Zon Leonard I.
Published: August 2005

The zebrafish (Danio rerio) has emerged as an ideal organism for the study of hematopoiesis, the process by which all the cellular elements of the blood are formed. These elements, including erythrocytes, granulocytes, monocytes, lymphocytes, and thrombocytes, are formed through complex genetic signaling pathways that are highly conserved throughout phylogeny. Large-scale forward genetic screens have identified numerous blood mutants in zebrafish, helping to elucidate specific signaling pathways important for hematopoietic stem cells (HSCs) and the various committed blood cell lineages. Here we review both primitive and definitive hematopoiesis in zebrafish, discuss various genetic methods available in the zebrafish model for studying hematopoiesis, and describe some of the zebrafish blood mutants identified to date, many of which have known human disease counterparts.
Rotor‐Bearing System Stability Performance Comparing Hybrid versus Conventional Bearings
Authors: Gomez-Mancilla Julio , Nosov Valeri , Silva-Navarro Gerardo
Published: August 2005

New closed‐form expressions for calculating the linear
stability thresholds for rigid and flexible Jeffcott systems and
the imbalance response for a rotor supported on a hybrid bearing
are presented. For typical bearings characteristics, expressions yield stability thresholds practically equal to those reported by
Lund (1966). The hybrid bearing design has a single injection
port whose location is so chosen to stabilize the bearing
performance and to reduce the steady equilibrium attitude angle.
Rotordynamics coefficients graphs for conventional and
pressurized bearings, as functions of bearing equilibrium
eccentricity and/or Sommerfeld number, are presented. Using the
rotordynamics coefficients into the expressions for the
corresponding velocity thresholds and the imbalance response, the
system stability and vibration performances are estimated and
analyzed. When comparing the Jeffcott flexible shaft supported on
two journal bearings of the conventional type with the hybrid
type, the results show a clear superiority of the pressurized
design as far as stability behavior is concerned. Specifically
for cases of flexible shafts with similar characteristics to
those used in industry, the analysis shows that this design yields
velocity thresholds 25%–40% higher compared to the
conventional circular ones. Also this bearing displays nonlinear
feeding pressure behavior, and it is capable of reducing the
synchronous vibration amplitude in most speed ranges, except
around the critical speed; moreover, for certain Jeffcott
configurations the amplitude reduction can be substantial.
CFD Analysis of the First‐Stage Rotor and Stator in a Two‐Stage Mixed Flow Pump
Authors: Miner Steven M.
Published: August 2005

A commercial computational fluid dynamics (CFD) code is
used to compute the flow field within the first‐stage rotor and
stator of a two‐stage mixed flow pump. The code solves the 3D
Reynolds‐averaged Navier‐Stokes equations in rotating and
stationary cylindrical coordinate systems for the rotor and
stator, respectively. Turbulence effects are modeled using a
standard k − ε turbulence model. Stage design
parameters are rotational speed 890 rpm, flow coefficient
φ = 0.116, head coefficient ψ = 0.094, and specific speed
2.01 (5475 US). Results from the study include velocities, and
static and total pressures for both the rotor and stator.
Comparison is made to measured data for the rotor. The comparisons
in the paper are for circumferentially averaged results and
include axial and tangential velocities, static pressure, and
total pressure profiles. Results of this study show that the
computational results closely match the shapes and magnitudes of
the measured profiles, indicating that CFD can be used to
accurately predict performance.
Wake Behavior behind Turbine Cascades in Compressible Two‐Dimensional Flows
Authors: Kurz Rainer
Published: August 2005

The goal of the paper is to describe wake parameters of
wakes from turbine cascades in compressible flows especially in
planes where the leading edge of the following blade row would be
located. Data from experiments with turbine cascades in
compressible flow will be used to derive a theoretical approach
which describes the wake growth and the recovery of the velocity
deficit. The theory is based on similarity assumptions. The
derived equations depend on simple and readily available
parameters such as overall losses, exit angle, and Mach or Laval
number. In compressible turbine flows, the influence of the
inviscid flow field is of great importance. In this paper, an
approach to take this influence into account when determining the
behavior of the wake is presented. Correlations for basic
characteristics of wakes in compressible flows are not readily
available. Such correlations are necessary as input to unsteady
flow and heat transfer calculation procedures for turbomachine
blades. Based on available data on wake behavior in the
compressible flow behind turbine blades, the correlations
presented describe the wake behavior from the trailing edge to the
confluence of the wakes of adjacent blades.
Analysis of Secondary Flows in Centrifugal Impellers
Authors: Brun Klaus , Kurz Rainer
Published: August 2005

Secondary flows are undesirable in centrifugal
compressors as they are a direct cause for flow (head) losses,
create nonuniform meridional flow profiles, potentially induce
flow separation/stall, and contribute to impeller flow slip; that
is, secondary flows negatively affect the compressor performance.
A model based on the vorticity equation for a rotating system was
developed to determine the streamwise vorticity from the normal
and binormal vorticity components (which are known from the
meridional flow profile). Using the streamwise vorticity results
and the small shear‐large disturbance flow method, the onset,
direction, and magnitude of circulatory secondary flows in a
shrouded centrifugal impeller can be predicted. This model is also
used to estimate head losses due to secondary flows in a
centrifugal flow impeller. The described method can be employed
early in the design process to develop impeller flow shapes that
intrinsically reduce secondary flows rather than using disruptive
elements such as splitter vanes to accomplish this task.
Effect of Channel Orientation and Rib Pitch‐to‐Height Ratio on Pressure Drop in a Rotating Square Channel with Ribs on Two Opposite Surfaces
Authors: Prabhu S. V. , Arora Neelabh , Vedula R. P.
Published: August 2005

The effect of channel orientation and rib pitch‐to‐height ratio on the pressure drop distribution in a rib‐roughened channel is an important issue in turbine blade cooling. The present investigation is a study of the overall pressure drop distribution in a square cross‐sectioned channel, with rib turbulators, rotating about an axis normal to the free stream. The ribs are configured in a symmetric arrangement on two opposite surfaces with a rib angle of 90∘ to the
mainstream flow. The study has been conducted for three Reynolds numbers, namely, 13 000, 17 000, and 22 000 with the rotation number varying from 0–0.38. Experiments have been carried out for
various rib pitch‐to‐height ratios (P/e) with a constant rib
height‐to‐hydraulic diameter ratio (e/D) of 0.1. The test
section in which the ribs are placed on the leading and trailing
surfaces is considered as the base case (orientation angle = 0∘, Coriolis force vector normal to the ribbed
surfaces). The channel is turned about its axis in steps of
15∘ to vary the orientation angle from 0∘ to
90∘. The overall pressure drop does not change
considerably under conditions of rotation for the base case.
However, for the other cases tested, it is observed that the
overall pressure drop increases with an increase in the rotation
number for a given orientation angle and also increases with an
increase in the orientation angle for a given rotation number.
This change is attributed to the variation in the separation zone
downstream of the ribs due to the presence of the Coriolis
force—local pressure drop data is presented which supports this
idea. At an orientation angle of 90∘ (ribs on the top and
bottom surfaces, Coriolis force vector normal to the smooth
surfaces), the overall pressure drop is observed to be maximum
during rotation. The overall pressure drop for a case with a rib
pitch‐to‐height ratio of 5 on both surfaces is found to be
the highest among all the rib pitch‐to‐height ratios covered in this
study with the maximum increase in the overall pressure drop being
as high as five times the corresponding no‐rotation case at the
highest rotation number of 0.38 and 90∘ orientation
angle.
Investigation of Flow Behavior around Corotating Blades in a Double‐Spindle Lawn Mower Deck
Authors: Chon W. , Amano R. S.
Published: August 2005

When the airflow patterns inside a lawn mower deck are
understood, the deck can be redesigned to be efficient and have an
increased cutting ability. To learn more, a combination of
computational and experimental studies was performed to
investigate the effects of blade and housing designs on a flow
pattern inside a 1.1m wide corotating double‐spindle lawn
mower deck with side discharge. For the experimental portion of
the study, air velocities inside the deck were measured using a
laser Doppler velocimetry (LDV) system. A high‐speed video camera
was used to observe the flow pattern. Furthermore, noise levels
were measured using a sound level meter. For the computational
fluid dynamics (CFD) work, several arbitrary radial sections of a
two‐dimensional blade were selected to study flow computations. A
three‐dimensional, full deck model was also developed for
realistic flow analysis. The computational results were then
compared with the experimental results.
Divergent Trends and Different Causal Logics: The Importance of Bargaining Centralization When Explaining Earnings Inequality across Advanced Democratic Societies
Authors: Oskarsson Sven
Published: August 2005

This article argues that centralized wage bargaining alters the causal logic in explanations of wage inequality, in the sense that common explanatory factors have different effects, given the degree of bargaining centralization. The evidence presented supports the theoretical argument. Using aggregate time-series cross-country data from fifteen capitalist democracies, the article shows that—given decentralized bargaining—trade with less developed countries, resources devoted to research and development, and government employment have inegalitarian effects on the wage distribution, whereas leftist governments and unionism compress wages. However, given centralized wage bargaining these effects gradually disappear or, in some cases, change direction.
Eco-terrorism or Justified Resistance? Radical Environmentalism and the “War on Terror”
Authors: Vanderheiden Steve
Published: August 2005

Radical environmental groups engaged in ecotage—or economic sabotage of inanimate objects thought to be complicit in environmental destruction—have been identified as the leading domestic terrorist threat in the post-9/11 “war on terror.” This article examines the case for extending the conventional definition of terrorism to include attacks not only against noncombatants, but also against inanimate objects, and surveys proposed moral limits suggested by proponents of ecotage. Rejecting the mistaken association between genuine acts of terrorism and ecotage, it considers the proper moral constraints upon ecotage through an examination of just war theory and nonviolent civil disobedience.
Measuring a Dimension of Spirituality for Health Research
Authors: Frey Bruce B. , Daaleman Timothy P. , Peyton Vicki
Published: August 2005

Health-related studies of spirituality are threatened by the lack of conceptual distinctions between religion and spirituality, the use of small, nongeneralizable samples, and by measurement error in many instruments that unreliably and invalidly capture this domain. The authors review the construct and validity evidence for the Spirituality Index of Well-Being (SIWB), an instrument designed to measure a dimension of spirituality linked to subjective well-being in patient populations. The SIWB was developed using qualitative research methods and subsequently conceptualized with two dimensions; self-efficacy and life scheme. Primary psychometric data from three sample populations are reviewed and summarized. A secondary, confirmatory factor analysis, using pooled data from all samples, supports the theoretical two-factor structure. In addition, SIWB scores correlate more strongly with established measures of well-being than the Spiritual Well-Being Scale (SWB) or other recognized religiosity instruments. The SIWB is a valid and reliable instrument that can be used in health-related studies.
Health and Living Arrangement Transitions Among China’s Oldest-Old
Authors: Zimmer Zachary
Published: August 2005

This article begins with the notion that the family in China acts altruistically, aiming toward the comfortable survival of all members. On the basis of this perspective, coresidence with older adults is more likely to occur when needs are greatest, for instance, when health deteriorates or a spouse dies. There is also the possibility of gender variation due to differences in authority and emotional bonds between older women and men and their families. These notions are tested using longitudinal data. Cross-sectional and transitional models link health status measures with living arrangement outcomes. Results show changes in living arrangements occur frequently. Functional limitations are more strongly associated with living arrangements than are other health indicators. Health indicators are more strongly related for those not married. Gender interactions show a health event is most likely to trigger a living arrangement response for a woman. Implications for a rapidly aging China are discussed.
Can We Better Prioritize Resources for Cost-Utility Research?
Authors: Neumann Peter J. , Rosen Allison B. , Greenberg Dan , Olchanski Natalia V. , Pande Richa , Chapman Richard H. , Stone Patricia W. , Ondategui-Parra Silvia , Nadai John , Siegel Joanna E. , Weinstein Milton C.
Published: August 2005

Purpose. We examined 512 published cost-utility analyses (CUAs) in the U.S. and other developed countries from 1976 through 2001 to determine: 1) the types of interventions studied; 2) whether they cover diseases and conditions with the highest burden; and, 3) to what extent they have covered leading health concerns defined by the Healthy People 2010 report. Data and Methods. We compared rankings of the most common diseases covered by the CUAs to rankings of U.S. disease burden. We also examined the extent to which CUAs covered key Healthy People 2010 priorites. Results. CUAs have focused mostly on pharmaceuticals (40%) and surgical procedures (16%). When compared to leading causes of DALYs, the data show overrepresentation of CUAs in cerebrovascular disease, diabetes, breast cancer, and HIV/AIDS, and underrepresentation in depression and bipolar disorder, injuries, and substance abuse disorders. Few CUAs have targeted Healthy People 2010 areas, such as physical activity. Conclusions. Published CUAs are associated with burden measures, but have not covered certain important health problems. These discrepancies do not alone indicate that society has been targeting resources for research inefficiently, but they do suggest the need to formalize the question of where each CUA research dollar might do the most good.
The QALY Model and Individual Preferences for Health States and Health Profiles over Time: A Systematic Review of the Literature
Authors: Tsuchiya Aki , Dolan Paul
Published: August 2005

The numbers of quality-adjusted life years (QALYs) gained are increasingly being used to represent the gains in individual utility from treatment. This requires that the value of a health improvement to an individual is a simple product of gains in quality of life and length of life. The article reports on a systematic review of the literature on 2 issues: whether the value of a state is affected by how long the state lasts, and by states that come before or after it. It was found that individual preferences over health are influenced by the duration of health states and their sequence. However, although there is much variation across individual respondents, the assumptions tend to hold much better when valuations are aggregated across respondents, which is encouraging for economic evaluations that rely on using average (mean or median) values.
Methods to Estimate the Optimal Threshold for Normally or Log-Normally Distributed Biological Tests
Authors: Jund Jérôme , Rabilloud Muriel , Wallon Martine , Ecochard René
Published: August 2005

Putting a screening or a diagnostic test into everyday use requires the determination of its threshold. The authors present methods that yield a point and an interval estimation of the threshold that maximize the population utility whenever the test results are normally or log-normally distributed among healthy and among diseased subjects, with equal variances. These methods were assessed for bias, coverage probability, coverage symmetry, and confidence-interval width using simulation. They proved to be asymptotically nonbiased and to have a satisfactory coverage probability whenever the sample sizes of the healthy and the diseased subjects are equal to or greater than 50. The methods were next applied to determine an optimal threshold for the antibody load used to diagnose congenital toxoplasmosis at birth. The methods are easy to implement and impose few constraints; however, the sample sizes should be carefully determined according to the required accuracy.
How Sensitive Are Cost-Effectiveness Analyses to Choice of Parametric Distributions?
Authors: Thompson Simon G. , Nixon Richard M.
Published: August 2005

Background . Cost-effectiveness analyses of clinical trial data are based on assumptions about the distributions of costs and effects. Cost data usually have very skewed distributions and can be difficult to model. The authors investigate whether choice of distribution can make a difference to the conclusions drawn. Methods . The authors compare 3 distributions for cost data—normal, gamma, and lognormal—using similar parametric models for the cost-effectiveness analyses. Inferences on the cost-effectiveness plane are derived, together with cost-effectiveness acceptability curves. These methods are applied to data from a trial of rapid magnetic resonance imaging (rMRI) investigation in patients with low back pain. Results . The gamma and lognormal distributions fitted the cost data much better than the normal distribution. However, in terms of inferences about cost-effectiveness, it was the normal and gamma distributions that gave similar results. Using the lognormal distribution led to the conclusion that rMRI was cost-effective for a range of willingness-to-pay values where assuming a gamma or normal distribution did not. Conclusions . Conclusions from cost-effectiveness analyses are sensitive to choice of distribution and, in particular, to how the upper tail of the cost distribution beyond the observed data is modeled. How well a distribution fits the data is an insufficient guide to model choice. A sensitivity analysis is therefore necessary to address uncertainty about choice of distribution.
Reducing the Influence of Anecdotal Reasoning on People’s Health Care Decisions: Is a Picture Worth a Thousand Statistics?
Authors: Fagerlin Angela , Wang Catharine , Ubel Peter A.
Published: August 2005

Background. People’s treatment decisions are often influenced by anecdotal rather than statistical information. This can lead to patients making decisions based on others’ experiences rather than on evidence-based medicine. Objective. To test whether the use of a quiz or pictograph decreases people’s reliance on anecdotal information. Design. Two cross-sectional survey studies using hypothetical scenarios. Participants read a scenario describing angina and indicated a preference for either bypass surgery or balloon angioplasty. The cure rate of both treatments was presented using prose, a pictograph, a quiz, or a pictograph and quiz combination. Participants read anecdotes from hypothetical patients who described the outcome of their treatment; the number of successful anecdotes was either representative or unrepresentative of the cure rates. Setting and Participants. Prospective jurors at the Philadelphia County Courthouse and travelers at the Detroit-Wayne County Metropolitan Airport. Measurements. Proportion of respondents preferring bypass over balloon angioplasty. Results. In study 1, when statistical information was presented in prose, treatment choices were influenced by anecdotes, with 41% of participants choosing bypass when the anecdotes were representative and only 20% choosing it when the anecdotes were unrepresentative (x2 = 14.40, P < 0.001). When statistics were reinforced with the pictograph and quiz, anecdotes had no significant influence on treatment decisions (38% choosing bypass when anecdotes were representative v. 44% when unrepresentative, x2 = 1.08, P > 0.20). In study 2, the tradeoff quiz did not reduce the impact of the anecdotes (27% v. 28% choosing bypass after receiving or not receiving the quiz, x2 < 1, P > 0.20). However, the pictograph significantly reduced the impact of anecdotes, with 27% choosing bypass after receiving no pictograph and 40% choosing bypass after receiving a pictograph (x2 = 6.44, P < 0.001). Conclusions. Presenting statistical information using a pictograph can reduce the undue influence of anecdotal reasoning on treatment choices.
Quality of Abstracts of Papers Reporting Original Cost-Effectiveness Analyses
Authors: Rosen Allison B. , Greenberg Dan , Stone Patricia W. , Olchanski Natalia V. , Neumann Peter J.
Published: August 2005

Background . Although many peer-reviewed journals have adopted standards for reporting cost-effectiveness analyses (CEAs), guidelines do not exist for the accompanying abstracts. Abstracts are the most easily accessed portion of journal articles, yet little is known about their quality. The authors examined the extent to which abstracts of published CEAs include key data elements (intervention, comparator, target population, study perspective) and assessed the effect of journal characteristics on reporting quality. Methods .Systematic review of the English-language medical literature from 1998 through 2001. The authors searched MEDLINE for original CEAs reported in costs per quality-adjusted life years(i.e., cost-utility analyses). Two independent readers abstracted data elements and met to resolve discrepancies. Results . Among the 303 abstracts reviewed, a clear description of the intervention was present in 94%, comparator in 71%, target population in 85%, and study perspective in 28%. All 4 data elements were reported in 20% of abstracts, 3 elements in 49%, 2 in 22%, and 0 or 1 in 9%. In journals with CEA-specific abstract reporting requirements, structured abstract requirements, or impact factors ≥ 10, significantly more data were included in abstracts than in journals without these features (P < 0.01 for all comparisons). Conclusions . Abstracts of published CEAs frequently omit data elements critical to proper study interpretation. An explicit core set of reporting standards is needed, based on the standards by the US Public Health Service’s Panel on Cost-Effectiveness for reporting of CEAs, but specific to the accompanying abstracts.
Management of Cardiogenic Shock Attributable to Acute Myocardial Infarction in the Reperfusion Era
Authors: Duvernoy Claire S. , Bates Eric R.
Published: August 2005

Cardiogenic shock is the leading cause of death among patients hospitalized with acute myocardial infarction. It is defined as tissue hypoperfusion resulting from ventricular pump failure in the presence of adequate intravascular volume. Rapid assessment and triage of patients presenting in cardiogenic shock followed by appropriate institution of supportive therapies including vasopressor and inotropic agents, mechanical ventilatory support, and intra-aortic balloon pump counterpulsation are critical for effective management of these patients. However, emergency percutaneous coronary intervention or coronary artery bypass graft surgery is required to decrease mortality rates. Novel approaches, including inhibition of nitric oxide synthase and new mechanical support devices, may further decrease mortality rates, which remain high despite reperfusion therapy.
Therapeutic Apheresis in Neurology Critical Care
Authors: Natarajan Neela , Weinstein Robert
Published: August 2005

Therapeutic apheresis has been widely accepted in the treatment of neurological disorders that are understood to be mediated by humoral and/or cellular immunity. The clinical presumption is that well-established and/or unknown insults cause damage to nerves or their myelin sheaths. The rationale for apheresis treatments for these neurological disorders relates to removal of offending immune (or other) mediators, thus blunting the attack and permitting recovery of nerve and/or myelin. This review will concentrate on the role of therapeutic apheresis, in particular therapeutic plasma exchange, in neurological disorders that may frequently be seen by intensivists.
Renal-Dose Dopamine: From Hypothesis to Paradigm to Dogma to Myth and, Finally, Superstition?
Authors: Jones Daryl , Bellomo Rinaldo
Published: August 2005

Acute renal failure (ARF) is common in the critically ill and is associated with a high mortality rate. Its pathogenesis is not understood. Because animal models use ischemia to induce experimental ARF, there is the widespread belief that lack of blood flow is responsible for ARF. Low-dose dopamine (LDD) has been shown to increase renal blood flow in animal and in human volunteers. Thus, it has been administered to humans for almost 3 decades in the belief that it would lead to renal arterial vasodilation and increase renal blood flow (RBF). However, the etiology of ARF in critical illness is likely multifactorial, and the contribution of hypovolemia and reduced renal perfusion is unknown. Furthermore, interindividual variation in the pharmacokinetics of dopamine typically results in poor correlation between blood levels and administered dose, making accurate and reliable delivery of LDD difficult. Finally, dopamine is a proximal tubular diuretic that increases Na+ delivery to tubular cells, thus increasing their oxygen demands. Accordingly, even if LDD were able to preferentially increase RBF, there is no guarantee that it would restore renal parenchymal oxygen homeostasis. More important, 2 meta-analyses and a large double-blind, prospective, multiple-center, randomized controlled trial have failed to demonstrate that dopamine protects the kidney in critically ill patients with ARF. Currently, there is insufficient evidence to support the use of renal-dose dopamine in the intensive care unit.
Can We Abandon Daily Routine Chest Radiography in Intensive Care Patients?
Authors: Graat Marleen E. , Stoker Jaap , Vroom Margreeth B. , Schultz Marcus J.
Published: August 2005

Two different schools of thought exist on the utility of daily routine chest radiographs in intensive care unit (ICU) patients: some ICU physicians argue that daily routine chest radiographs are indicated in all patients who have cardiopulmonary problems or are receiving artificial ventilation. Others state that chest radiographs should be made on indication only, for example, following a change in clinical status or change of supportive devices. Most studies on this topic have simply reported the existence of several findings on chest radiographs; some investigators tried to determine whether such findings were new and/or unexpected and whether they caused a therapy change. A restrictive strategy has been compared with a daily routine strategy in only 2 clinical trials: 1 study conducted in a pediatric ICU (pediatric ICUs usually have low mortality rates), and the other a rather small (and probably underpowered) study. The debate about discontinuing daily routine chest radiographs in the ICU is still not settled.
Applicability of Prediction Rules in Patients With Community-Acquired Pneumonia Requiring Intensive Care: A Pilot Study
Authors: Smyrnios Nicholas A. , Schaefer Oren P. , Collins Roslinde M. , Madison J. Mark
Published: August 2005

Little attention has been paid to developing prediction rules that could assist in deciding which patients with community-acquired pneumonia (CAP) need intensive care. Four existing prediction rules were examined to determine if any could predict the need for intensive care in these patients. The prediction rules studied were British Thoracic Society (BTS), Conte et al, Leroy et al, and Fine et al. Thirty-two patients admitted to the medical or coronary intensive care unit (ICU) during 1 year with pneumonia Diagnosis Related Group 079 or 089 were evaluated. The sensitivity of each rule for identifying a need for ICU admission in our group was BTS .72 using both rules together, Conte et al .47, Leroy et al .56, and Fine et al .84. It was concluded that these rules poorly identify the need for ICU admission for patients with severe CAP. Of the 4 rules tested, the BTS rule was the simplest, and the Fine et al rule was the most sensitive. None of them performed well enough to be used for decision making in individual patients.
Following the Leader? Presidential Influence Over Congress in the Passage of Federal Crime Control Policy
Authors: Oliver Willard M. , Barlow David E.
Published: August 2005

This study explores the relationship between the president, Congress, and the passage of federal crime control legislation in the United States from 1946 to 1996. The theory of presidential influence over Congress is used to predict the impact of presidential activity on congressional passage of public laws related to crime. It is hypothesized that the more attention presidents give to the issue of crime, the more attention Congress will give to the topic, thus helping to ensure the papssage of crime legislation. Using a multivariate time-series analysis of data collected from the Public Papers of the Presidents of the United States and the United States Statutes at Large, the study finds some support for the hypothesis, alongside presidential popularity, the official crime rate, and the political cycle.
The Utility of Social Capital and Collective Efficacy: Social Control Policy in Nonmetropolitan Settings
Authors: Cancino Jeffrey Michael
Published: August 2005

Researchers and practitioners have made great strides at implementing crime reduction and prevention policies in urban areas; however, such policies are largely absent in less densely populated nonmetropolitan settings. This article provides a review of major findings from two recent nonmetropolitan studies using survey data from 1,125 citizens nested in 31 nonmetropolitan residential units (RUs) located in the state of Michigan. Hierarchical linear modeling results provide empirical evidence that the differential ability of nonmetropolitan Michigan residents to realize mutual trust and solidarity (i.e., social cohesion) is a major source of RU variation in citizens’ perceived incivility and burglary. Toward this end, several policy recommendations are endorsed in nonmetropolitan communities, whereby resources of social capital can help facilitate collective efficacy for the purpose of social control and improvement of citizen quality of life. Using a social capital framework is likely to benefit rural researchers and policy makers alike.
One Size Fits All? A Gender-Neutral Approach to a Gender-Specific Problem: Contrasting Batterer Treatment Programs for Male and Female Offenders
Authors: Miller Susan L. , Gregory Carol , Iovanni LeeAnn
Published: August 2005

As an unintended consequence of more strict arrest policies aimed at deterring domestic violence offenders, many battered women have been arrested and court mandated to a treatment program intended for male abusers. This practice raises numerous concerns regarding the impact on specific victims as well as the potential for undermining decades of work aimed at holding offenders accountable. It also offers researchers another lens through which treatment programs can be viewed. This research compares and contrasts two domestic violence intervention programs: one for male offenders and one for female offenders. Specifically, it attempts to answer, What are the challenges in applying a one-size-fits-all and gender-neutral approach to a problem that embodies gender-specific issues and power dynamics? Does treatment designed for battering men need to be altered when applied to women? And how does feminist philosophy as exemplified by the Duluth model translate into groups for men and women?
Now Serving Part Two Crimes: Testing the Relationship Between Welfare Spending and Property Crimes
Authors: Burek Melissa W.
Published: August 2005

Studies that examine the effects of welfare, specifically the program of Aid to Families of Dependent Children (AFDC), have primarily examined the relationship between public assistance spending and index, or part one, offenses. In general, the results of past studies have found a negative relationship between welfare and serious crime rates. To date, however, few studies have examined the effects of welfare on the more prevalent part two crimes. Given that previous examinations have found an inverse relationship between index crimes and welfare spending, changes in levels of spending could potentially affect both categories of crime in unwanted directions. As such, this study examined both part one and part two property crimes in relation to welfare spending from 1980 to 1990 in Kentucky counties. Significant positive findings were observed between AFDC spending and part two property crimes.
Sex Differences in the Responses of the Human Amygdala
Authors: Hamann Stephan
Published: August 2005

The amygdala is a structure in the temporal lobe that has long been known to play a key role in emotional responses and emotional memory in both humans and nonhuman animals. Growing evidence from recent neuroimaging studies points to a new, expanded role for the amygdala as a critical structure that mediates sex differences in emotional memory and sexual responses. This review highlights current findings from studies of sex differences in human amygdala response during emotion-related activities, such as formation of emotional memories and sexual behavior, and considers how these findings contribute to the understanding of behavioral differences between men and women. Clinical implications for the understanding of sex differences in the prevalence of affective and anxiety disorders are discussed, and future directions in the study of the amygdala’s role in human sex differences are outlined.
Brain-Derived Neurotrophic Factor in Amygdala-Dependent Learning
Authors: Rattiner Lisa M. , Davis Michael , Ressler Kerry J.
Published: August 2005

The neurotrophin brain-derived neurotrophic factor (BDNF) has recently emerged as a possible molecular mediator of activity-dependent synaptic plasticity underlying learning and memory. Long-term potentiation (LTP) within the hippocampus and hippocampally dependent behaviors has been the primary model for examining the role of BDNF in learning and memory. However, these studies are limited by an incomplete understanding of the complex behavioral function of hippocampal circuitry, making it difficult to unravel the molecular machinery responsible for the formation and storage of these memories. In contrast, the amygdala and its role in Pavlovian fear conditioning promise to provide us with new insights into the mechanisms of BDNF-mediated synaptic plasticity during the learning and memory process. This article reviews the different levels of research on BDNF in learning and memory. The focus is primarily on the use of Pavlovian fear conditioning as a learning model that allows for the examination of the role of BDNF in the amygdala, following a single learning session and within a well-understood neural circuit.
P2X Receptors: Targets for Novel Analgesics?
Authors: Kennedy Charles
Published: August 2005

The ability of adenosine 5′-triphosphate (ATP) to evoke acute pain has been known for many years, but its role in nociceptive signaling is only now becoming clear. ATP acts via P2X and P2Y receptors, and of particular importance here is the P2X3 receptor. It is expressed selectively at high levels in nociceptive sensory neurons, where it forms functional receptors on its own and in combination with the P2X2 receptor. Recent reports using gene knockout methods; antisense oligonucleotide and small, interfering RNA technologies; and a novel, selective P2X3 antagonist, A-317491, show that P2X3 receptors are involved in chronic inflammatory and neuropathic pain. The mRNA for other P2X subunits is also found in sensory neurons, and there is evidence for functional P2X1/5 or P2X2/6 heteromers in some of these. These data support the possibility that P2X receptors, particularly the P2X3 subtype, could be targeted in the search for new, effective analgesics.
Minocycline as a Neuroprotective Agent
Authors: Stirling David P. , Koochesfahani Kaveh M. , Steeves John D. , Tetzlaff Wolfram
Published: August 2005

Several studies have shown that minocycline, a semisynthetic, second-generation tetracycline derivative, is neuroprotective in animal models of central nervous system trauma and several neurodegenerative diseases. Common to all these reports are the beneficial effects of minocycline in reducing neural inflammation and preventing cell death. Here, the authors review the proposed mechanisms of action of minocycline and suggest that minocycline may inhibit several aspects of the inflammatory response and prevent cell death through the inhibition of the p38 mitogen-activated protein kinase pathway, an important regulator of immune cell function and cell death.
Migraine: New Molecular Mechanisms
Authors: Pietrobon Daniela
Published: August 2005

Migraine is an episodic headache disorder affecting more than 10% of the general population. Migraine arises from a primary brain dysfunction that leads to activation and sensitization of the trigeminovascular system. A major incompletely understood issue in the neurobiology of migraine concerns the molecular and cellular mechanisms that underlie the primary brain dysfunction and lead to activation and sensitization of the trigeminovascular system, thus generating and maintaining migraine pain. Here the author reviews recent discoveries that have advanced our understanding of these mechanisms toward a unifying pathophysiological hypothesis, in which cortical spreading depression (CSD), the phenomenon underlying migraine aura, assumes a key role. In particular, the author discusses the main recent findings in the genetics and neurobiology of familial hemiplegic migraine and the insights they provide into the molecular and cellular mechanisms that may lead to the increased susceptibility of CSD in migraineurs.
Dendritic Release of Retrograde Messengers Controls Synaptic Transmission in Local Neocortical Networks
Authors: Zilberter Yuri , Harkany Tibor , Holmgren Carl D.
Published: August 2005

The contribution of retrograde signaling to information processing in the brain has been contemplated for a long time, especially with respect to central nervous system development and long-term synaptic plasticity. During the past few years, however, the concept of retrograde signaling has been expanding to include short-term modifications of synaptic efficacy. The classic point of view on synaptic transmission represents it as a unidirectional transfer of information from presynaptic to postsynaptic sites. This paradigm has, however, been questioned in several experimental studies of neurons in different brain regions. These results suggest that a fast retrograde signal, which provides feedback, exists in active synaptic contacts. In particular, it was found that the dendritic release of retrograde messengers controls the efficacy of synaptic transmission in both excitatory and inhibitory connections between neocortical pyramidal cells and interneurons. The present review discusses these findings and the mechanisms underlying synaptic retrograde signaling.
Thalamic Mechanisms of EEG Alpha Rhythms and Their Pathological Implications
Authors: Hughes Stuart W. , Crunelli Vincenzo
Published: August 2005

During relaxed wakefulness, the human brain exhibits pronounced rhythmic electrical activity in the α frequency band (8-13 Hz). This activity consists of 3 main components: the classic occipital α rhythm, the Rolandic μ rhythm, and the so-called third rhythm. In recent years, the long-held belief that α rhythms are strongly influenced by the thalamus has been confirmed in several animal models and, in humans, is well supported by numerous noninvasive imaging studies. Of specific importance is the emergence of 2 key cellular thalamic mechanisms, which come together to generate locally synchronized α activity. First, a novel form of rhythmic burst firing, termed high-threshold (HT) bursting, which occurs in a specialized subset of thalamocortical (TC) neurons, and second, the interconnection of this subset via gap junctions (GJs). Because repetitive HT bursting in TC neurons occurs in the range of 2 to13 Hz, with the precise frequency increasing with increasing depolarization, the same cellular components that underlie thalamic α rhythms can also lead to θ (2-7 Hz) rhythms when the TC neuron population is less depolarized. As such, this scenario can explain both the deceleration of α rhythms that takes place during early sleep and the chronic slowing that characterizes a host of neurological and psychiatric disorders.
Do Interictal Spikes Drive Epileptogenesis?
Authors: Staley Kevin , Hellier Jennifer L. , Dudek F. Edward
Published: August 2005

Interictal spikes are periodic, very brief bursts of neuronal activity that are observed in the electroencephalogram of patients with chronic epilepsy. These spikes are useful diagnostically, but we do not know why they are so strongly associated with the spontaneous seizures that characterize chronic epilepsy. Interictal spikes appear before the first spontaneous seizures in animal models of acquired epilepsy, and spikes are sufficient to induce long-term changes in synaptic connections between neurons. Thus, spikes may guide the development of the neuronal circuits that initiate spontaneous seizures. If so, then attempts to prevent or cure epilepsy may best be directed at spikes rather than seizures.
Metaphors and Diaphors in Science Communication
Authors: Leydesdorff Loet , Hellsten Iina
Published: August 2005

“Stem cell research” has become a subject of political discussion in recent years because of its social and ethical implications. The intellectual research program, however, has a history of several decades. Therapeutic applications and patents on the basis of stem cell research became available during the 1990s. Currently, the main applications of stem cell research are found in marrow transplantation (e.g., for the treatment of leukemia). In this study, the various meanings of the term stem cell are examined in these different contexts of research, applications, and policy debates. Translation mechanisms between contexts are specified, and a quantitative indicator for the degree of codification is proposed.
Trying to Relate
Authors: Ruth Amanda , Lundy Lisa , Telg Ricky , Irani Tracy
Published: August 2005

This study uses a descriptive survey to examine the perceptions agricultural scientists have of the news media and the perceived need for media relations skills. The results showed that respondents were more negative about national news coverage and more positive about local news coverage of agricultural and scientific stories. They also were more favorable in their perceptions of coverage of general science topics than of stories in their agricultural discipline. Significant differences were found in respondents’ confidence in communicating with the news media on the basis of gender and age. Overall, respondents were confident in their media relations capabilities; however, areas in which respondents indicated they might take training included communicating in crisis situations and writing newspaper columns.
Cultural Representations of Gender and Science
Authors: Steinke Jocelyn
Published: August 2005

Images of female scientists and engineers in popular films convey cultural and social assumptions about the role of women in science, engineering, and technology (SET).This study analyzed cultural representations of gender conveyed through images of female scientists and engineers in popular films from 1991 to 2001. While many of these depictions of female scientists and engineers emphasized their appearance and focused on romance, most depictions also presented female scientists and engineers in professional positions of high status. Other images that showed the female scientists and engineers’ interactions with male colleagues, however, reinforced traditional social and cultural assumptions about the role of women in SET through overt and subtle forms of stereotyping. This article explores the significance of these findings for developing programs to change girls’ perceptions of scientists and engineers and attitudes toward SET careers.