bluuebunny/crossref_metadata_2025 huggingface dataset:
Temporal and Spatial Growth of Wind Waves
Authors: Stiassnie M. , Agnon Y. , Janssen P. A. E. M.
Published: February 2007

A solution of Rayleigh’s instability equation, which circumvents the apparent critical-layer singularity, is provided. The temporal and spatial growth rates of water waves exposed to a logarithmic wind profile are calculated and discussed. The findings are similar to previously published results, except for shear velocity–to–wave celerity ratios larger than 2, where the newly calculated growth rates start to decrease after having reached a distinct maximum. The ratio of the spatial to temporal growth rates is examined. It is shown to deviate by up to 20% from the leading-order value of 2. The implications of the growth rate to the modal distributions of energy input from wind to waves, for young and mature seas, and in temporal/spatial growth scenarios, are analyzed.
The Varieties of Capitalism and Hybrid Success
Authors: Campbell John L. , Pedersen Ove K.
Published: February 2007

The varieties of capitalism literature maintains that advanced capitalist countries whose institutions best fit either the liberal or coordinated market economy types will perform better than countries whose institutions are mixed. This is because hybrids are less likely to yield functionally beneficial institutional complementarities. The authors challenge this assertion. Denmark has performed as well as many purer cases during the 1990s. And Denmark has recently developed a more hybrid form than is generally recognized by (a) increasing the exposure of actors to market forces and (b) decentralizing collective learning and decision making. The institutional complementarities associated with such hybridization have contributed to its success; however, these complementarities are based on institutional heterogeneity rather than homogeneity. This is demonstrated by analyses of three cases: Danish labor markets, vocational training, and industrial policy. The implication of the authors’ argument is that the varieties of capitalism theory is logically flawed.
Voting in Open Economies
Authors: Hellwig Timothy , Samuels David
Published: February 2007

What are the electoral consequences of global market integration? Although recent discussions of politics and markets have much to say on globalization’s implications for policy outcomes, the impact of market integration on representative democracy has received scant attention. This article addresses this omission. We extend the globalization literature to develop two competing hypotheses regarding the influence of open economies on electoral accountability. Predictions are tested using a new data set covering elections from 75 countries over 27 years. Results support a government constraint hypothesis: Exposure to the world economy weakens connections between economic performance and support for political incumbents. By redirecting concerns from the policy implications of globalization and toward its electoral consequences, findings highlight the influence of voter perceptions and of vote-seeking politicians in the politics of globalization.
The Congressional Politics of Decentralization
Authors: Z. Rodrigo Mardones
Published: February 2007

This article explains why legislators in a centralized polity support decentralizing laws. Using Chile as a case study, it assesses two standard explanations for this support: party nomination procedures, which is disregarded; and electoral strategies, which is accepted. A novel finding is that party ideology is also a predictor of support for decentralization, with parties of the Right less likely to offer it. The author also argues that a legislator with a sub-national rather than national background is more likely to back such reforms in an attempt to enhance his or her reputation within the constituency. The author tests these and other hypotheses by combining qualitative arguments and regression analysis. The latter is performed on an original database of legislator biographical information, party electoral performance, regional GDP figures, and individual legislator support for 46 decentralizing laws approved in Chile between 1990 and 2006.
Lexical and referential influences on on-line spoken language comprehension: A comparison of adults and primary-school-age children
Authors: Kidd Evan , Bavin Edith L.
Published: February 2007

This paper reports on two studies investigating children's and adults' processing of sentences containing ambiguity of prepositional phrase (PP) attachment. Study 1 used corpus data to investigate whether cues argued to be used by adults to resolve PP-attachment ambiguities are available in child-directed speech. Study 2 was an on-line reaction time study investigating the role of lexical and referential biases in syntactic ambiguity resolution by children and adults. Forty children (mean age 8;4) and 37 adults listened to V-NP-PP sentences containing temporary ambiguity of PP-attachment. The sentences were manipulated for (i) verb semantics, (ii) the definiteness of the object NP, and (iii) PP-attachment site. The children and adults did not differ qualitatively from each other in their resolution of the ambiguity. A verb semantics by attachment interaction suggested that different attachment analyses were pursued depending on the semantics of the verb. There was no influence of the definiteness of the object NP in either children's or adults' parsing preferences. The findings from the on-line task matched up well with the corpus data, thus identifying a role for the input in the development of parsing strategies.
Arthroscopically assisted Medial Reefing without Routine Lateral Release for Patellar Instability
Authors: Miller Jennifer R. , Adamson Gregory J. , Pink Marilyn M. , Fraipont Michael J. , Durand Pierre
Published: February 2007

Background

Patellofemoral instability in patients with normal alignment has been effectively treated with medial reefing procedures and a lateral release. Recent research suggests that a lateral release may not be necessary in patients without excessive patellar tilt.

Hypothesis

Arthroscopically assisted medial reefing without lateral release is as effective as techniques with a lateral release reported in the literature.

Study Design

Case series; Level of evidence, 4.

Methods

Twenty-four patients (25 knees) were observed for an average of 60 months. Preoperatively, patients underwent a history, physical examination, and radiographic evaluation. At follow-up, a physical examination and radiographic evaluation were repeated. Preoperative and postoperative Lysholm and Tegner scores were calculated. A subjective questionnaire was also completed. Comparative statistics were used for the preoperative and postoperative scores (P < .05).

Results

Ninety-six percent (24/25) were satisfied with their results, and all patients would have the same procedure performed again. Subjective symptom scores improved significantly. Lysholm knee scores improved from an average of 54 to 91 (P < .001). Tegner activity level improved from an average of 3.3 to 6.2 (P < .001). Significant improvement was seen in patellar mobility, apprehension, and patellofemoral tenderness with compression. Range of motion, muscle atrophy, and tilt did not change significantly. Congruence angles improved from 4.4° to —2.5° (P = .009), lateral patellofemoral angles improved from 5.5° to 8.7° (P = .011), and lateral patellar displacement improved from 2.0 to 0.2 mm (P < .044). There were no recurrent dislocations or subluxations.

Conclusion

Arthroscopically assisted medial reefing, without lateral release, is an effective treatment for patients with recurrent patellofemoral instability and normal alignment.
Radiographic Landmarks for Femoral Tunnel Placement in Medial Patellofemoral Ligament Reconstruction
Authors: Schöttle Philip B. , Schmeling Arno , Rosenstiel Nikolaus , Weiler Andreas
Published: February 2007

Background

Reconstruction of the medial patellofemoral ligament has recently become popular for restoring patellofemoral stability. Femoral insertion site anatomy of the medial patellofemoral ligament has been described. This anatomical insertion has been inferred to be the isometric point in medial patellofemoral ligament reconstruction, but data about radiographic landmarks for a postoperative or intraoperative control are missing.

Purpose

To determine the radiographic landmarks for control of postoperative and intraoperative femoral medial patellofemoral ligament insertion.

Study Design

Descriptive laboratory study.

Methods

Eight fresh-frozen human knees were dissected, and the medial patellofemoral ligament was exposed. After identification of the femoral medial patellofemoral ligament insertion site, the insertion center was marked with a lead ball of 2-mm diameter. Straight lateral radiographs were taken, and posterior-anterior as well as proximal-distal position were evaluated.

Results

Six of 8 insertion points were anterior to a line representing an extension of the posterior cortex, 1 point was touching this line, and 1 point was posterior to it. All points were situated distal to the posterior origin of the medial femoral condyle and proximal to the most posterior point of the Blumensaat line.

Conclusion

A reproducible anatomical and radiographic point, 1 mm anterior to the posterior cortex extension line, 2.5 mm distal to the posterior origin of the medial femoral condyle, and proximal to the level of the posterior point of the Blumensaat line on a lateral radiograph with both posterior condyles projected in the same plane, shows the mean femoral medial patellofemoral ligament center.

Clinical Relevance

This radiographic point may be useful both intraoperatively and postoperatively.
Separating Planning and Attention
Authors: Puhan Gautam , Das J. P. , Naglieri Jack A.
Published: February 2007

In this article the authors present several justifications in favor of the position that the constructs of planning and attention as described in the planning, attention, simultaneous, and successive (PASS) theory of information processing are separate but interdependent processes. There are two parts to the article. The first part comprises a discussion of issues on the need for separating planning and attention and provides evidential validity by reviewing some selected studies. The second part reexamines a factor-analytic study that has questioned the separation of planning and attention processes. The reexamination showed a negligible statistical difference between the proposed three-factor model and the previously established four-factor model. Because the evidential validity of the four-factor model seems reasonably strong, the authors conclude by suggesting that there is little reason to choose the three-factor model that combines attention with planning.
Some Results in the Dynamics of Viscoelastic Mixtures
Authors: Galeş C.
Published: February 2007

The present article studies some qualitative properties of solutions in the dynamics of viscoelastic mixtures made by two constituents: a porous elastic solid and a viscous fluid. In this sense, some results concerning the theory of semigroups of linear operators are used to establish the existence and uniqueness of the weak solutions of the initial boundary value problems associated with the linear theory. The continuous dependence problem upon initial data and supply terms is also investigated. Then, the temporal behavior is studied in terms of the Cesáro means of various parts of the total energy. The relations that describe the asymptotic behavior of mean energies are established by using some Lagrange—Brun identities.
Neutrophil elastase depends on serglycin proteoglycan for localization in granules
Authors: Niemann Carsten U. , Åbrink Magnus , Pejler Gunnar , Fischer Rikke L. , Christensen Erik I. , Knight Stefan D. , Borregaard Niels
Published: February 2007

Granule proteins play a major role in bacterial killing by neutrophils. Serglycin proteoglycan, the major intracellular proteoglycan of hematopoietic cells, has been proposed to play a role in sorting and packing of granule proteins. We examined the content of major neutrophil granule proteins in serglycin knockout mice and found neutrophil elastase absent from mature neutrophils as shown by activity assay, Western blotting, and immunocytochemistry, whereas neutrophil elastase mRNA was present. The localization of other neutrophil granule proteins did not differ between wild-type and serglycin knockout mice. Differential counts and neutrophil ultrastructure were unaffected by the lack of serglycin, indicating that defective localization of neutrophil elastase does not induce neutropenia itself, albeit mutations in the neutrophil elastase gene can cause severe congenital neutropenia or cyclic neutropenia. The virulence of intraperitoneally injected Gram-negative bacteria (Klebsiella pneumoniae) was increased in serglycin knockout mice compared with wild-type mice, as previously reported for neutrophil elastase knockout mice. Thus, serglycin proteoglycan has an important role in localizing neutrophil elastase in azurophil granules of neutrophils, while localization of other granule proteins must be mediated by other mechanisms.
Growth factor independent 1B (Gfi1b) is an E2A target gene that modulates Gata3 in T-cell lymphomas
Authors: Xu Wei , Kee Barbara L.
Published: February 2007

The E2A transcription factors are required for normal T lymphopoiesis and to prevent T-lymphocyte progenitor transformation. Ectopic expression of E2A proteins in E2A-deficient lymphomas results in growth arrest and apoptosis, indicating that these cells remain responsive to the targets of E2A. Here we identify the transcriptional repressor growth factor independent 1B (Gfi1b) as a target of E2A that promotes growth arrest and apoptosis in lymphomas. Gfi1b expression in primary T-lymphocyte progenitors is dependent on E2A and excess Gfi1b prevents the outgrowth of T lymphocyte progenitors in vitro. Gfi1b represses expression of Gata3, a transcription factor whose appropriate regulation is required for survival of lymphomas and T-lymphocyte progenitors. We also show that ectopic expression of Gata3 in lymphomas promotes expression of Gfi1b, indicating that these proteins may function in an autoregulatory loop that maintains appropriate levels of Gata3. Therefore, we propose that E2A proteins prevent lymphoma cell expansion, at least in part through regulation of Gfi1b and modulation of Gata3 expression.
Dasatinib induces significant hematologic and cytogenetic responses in patients with imatinib-resistant or -intolerant chronic myeloid leukemia in accelerated phase
Authors: Guilhot Francois , Apperley Jane , Kim Dong-Wook , Bullorsky Eduardo O. , Baccarani Michele , Roboz Gail J. , Amadori Sergio , de Souza Carmino A. , Lipton Jeffrey H. , Hochhaus Andreas , Heim Dominik , Larson Richard A. , Branford Susan , Muller Martin C. , Agarwal Prasheen , Gollerkeri Ashwin , Talpaz Moshe
Published: February 2007

Treatment options are limited for patients with imatinib-resistant or -intolerant accelerated phase chronic myeloid leukemia (CML-AP). Dasatinib is a novel, potent, oral, multitargeted kinase inhibitor of BCR-ABL and SRC-family kinases that showed marked efficacy in a phase 1 trial of patients with imatinib-resistant CML. Results are presented for 107 patients with CML-AP with imatinib-resistance or -intolerance from a phase 2, open-label study further evaluating dasatinib efficacy and safety. At 8 months' minimum follow-up, 81%, 64%, and 39% of patients achieved overall, major (MaHR), and complete hematologic responses, respectively, whereas 33% and 24% attained major and complete cytogenetic remission. Of 69 patients who achieved MaHR, 7 progressed. Seventy-six percent of patients are estimated to be alive and progression-free at 10 months. Response rates for the 60% of patients with baseline BCR-ABL mutations did not differ from the total population. Dasatinib was well tolerated: most nonhematologic adverse events (AEs) were mild to moderate; no imatinib-intolerant patients discontinued dasatinib because of AEs. Although common (76% of patients with severe neutropenia), cytopenias were manageable through dose modification. In summary, dasatinib induced significant hematologic and cytogenetic responses in patients with imatinib resistance or intolerance, was well tolerated, and may represent a potent new therapeutic option for CML-AP. Further follow-up is warranted. This trial was registered at www.clinicaltrials.gov as #CA180005.
A distinct epigenetic signature at targets of a leukemia protein
Authors: Rossetti Stefano , Hoogeveen André T , Liang Ping , Stanciu Cornel , van der Spek Peter , Sacchi Nicoletta
Published: February 2007

Background

Human myelogenous leukemia characterized by either the non random t(8; 21)(q22; q22) or t(16; 21)(q24; q22) chromosome translocations differ for both their biological and clinical features. Some of these features could be consequent to differential epigenetic transcriptional deregulation at AML1 targets imposed by AML1-MTG8 and AML1-MTG16, the fusion proteins deriving from the two translocations. Preliminary findings showing that these fusion proteins lead to transcriptional downregulation of AML1 targets, marked by repressive chromatin changes, would support this hypothesis. Here we show that combining conventional global gene expression arrays with the power of bioinformatic genomic survey of AML1-consensus sequences is an effective strategy to identify AML1 targets whose transcription is epigenetically downregulated by the leukemia-associated AML1-MTG16 protein.

Results

We interrogated mouse gene expression microarrays with probes generated either from 32D cells infected with a retroviral vector carrying AML1-MTG16 and unable of granulocyte differentiation and proliferation in response to the granulocyte colony stimulating factor (G-CSF), or from 32D cells infected with the cognate empty vector. From the analysis of differential gene expression alone (using as criteria a p value < 0.01 and an absolute fold change > 3), we were unable to conclude which of the 37 genes downregulated by AML1-MTG16 were, or not, direct AML1 targets. However, when we applied a bioinformatic approach to search for AML1-consensus sequences in the 10 Kb around the gene transcription start sites, we closed on 17 potential direct AML1 targets. By focusing on the most significantly downregulated genes, we found that both the AML1-consensus and the transcription start site chromatin regions were significantly marked by aberrant repressive histone tail changes. Further, the promoter of one of these genes, containing a CpG island, was aberrantly methylated.

Conclusion

This study shows that a leukemia-associated fusion protein can impose a distinct epigenetic repressive signature at specific sites in the genome. These findings strengthen the conclusion that leukemia-specific oncoproteins can induce non-random epigenetic changes.
Closing the access gap for health innovations: an open licensing proposal for universities
Authors: Chaifetz Samantha , Chokshi Dave A , Rajkumar Rahul , Scales David , Benkler Yochai
Published: February 2007

Background

This article centers around a proposal outlining how research universities could leverage their intellectual property to help close the access gap for health innovations in poor countries. A recent deal between Emory University, Gilead Sciences, and Royalty Pharma is used as an example to illustrate how 'equitable access licensing' could be put into practice.

Discussion

While the crisis of access to medicines in poor countries has multiple determinants, intellectual property protection leading to high prices is well-established as one critical element of the access gap. Given the current international political climate, systemic, government-driven reform of intellectual property protection seems unlikely in the near term. Therefore, we propose that public sector institutions, universities chief among them, adopt a modest intervention – an Equitable Access License (EAL) – that works within existing trade-law and drug-development paradigms in order to proactively circumvent both national and international obstacles to generic medicine production. Our proposal has three key features: (1) it is prospective in scope, (2) it facilitates unfettered generic competition in poor countries, and (3) it centers around universities and their role in the biomedical research enterprise. Two characteristics make universities ideal agents of the type of open licensing proposal described. First, universities, because they are upstream in the development pipeline, are likely to hold rights to the key components of a wide variety of end products. Second, universities acting collectively have a strong negotiating position with respect to other players in the biomedical research arena. Finally, counterarguments are anticipated and addressed and conclusions are drawn based on how application of the Equitable Access License would have changed the effects of the licensing deal between Emory and Gilead.
Stability of early-phase primary psychotic disorders with
concurrent substance use and substance-induced psychosis
Authors: Caton Carol L. M. , Hasin Deborah S. , Shrout Patrick E. , Drake Robert E. , Domínguez Boanerges , First Michael B. , Samet Sharon , Schanzer Bella
Published: February 2007

Background

The stability of the diagnostic distinction between a substance-induced
psychosis and a primary psychotic disorder co-occurring with substance
use is not established.

Aims

To describe DSM – IV diagnostic changes over 1 year and determine the
predictive validity of baseline indicators of the substance-induced
psychosis v. primary psychosis distinction.

Method

We conducted a 1-year follow-up study of 319 psychiatric emergency
department admissions with diagnoses of early-phase psychosis and
substance use comorbidity.

Results

Of those with a baseline DSM—IV diagnosis of substance-induced psychosis,
25% had a diagnosis of primary psychosis at follow-up. These patients had
poorer premorbid functioning, less insight into psychosis and greater
family mental illness than patients with a stable diagnosis of
substance-induced psychosis. Reclassifying change cases to primary
psychoses on follow-up, key baseline predictors of the
primary/substance-induced distinction at 1 year also included greater
family history of mental illness in the primary psychosis group.

Conclusions

Further study of substance-induced psychoses should employ
neuroscientific and behavioural approaches. Study findings can guide more
accurate diagnoses at first treatment.
Psychological treatments for chronic post-traumatic stress disorder
Authors: Bisson Jonathan I. , Ehlers Anke , Matthews Rosa , Pilling Stephen , Richards David , Turner Stuart
Published: February 2007

Background

The relative efficacy of different psychological treatments for chronic post-traumatic stress disorder (PTSD) is unclear.

Aims

To determine the efficacy of specific psychological treatments for chronic PTSD.

Method

In a systematic review of randomised controlled trials, eligible studies were assessed against methodological qualitycriteria and data were extracted and analysed.

Results

Thirty-eight randomised controlled trials were included in the meta-analysis. Trauma-focused cognitive-behavioural therapy (TFCBT), eye movement desensitisation and reprocessing (EMDR), stress management and group cognitive-behavioural therapy improved PTSD symptoms more than waiting-list or usual care. There was inconclusive evidence regarding other therapies. There was no evidence of a difference in efficacy between TFCBT and EMDR butthere was some evidence that TFCBT and EMDR were superior to stress management and other therapies, and that stress management was superior to other therapies.

Conclusions

The first-line psychological treatment for PTSD should be trauma-focused (TFCBTor EMDR).
Best practice when service users do not consent to sharing
information with carers
Authors: Slade Mike , Pinfold Vanessa , Rapaport Joan , Bellringer Sophie , Banerjee Sube , Kuipers Elizabeth , Huxley Peter
Published: February 2007

Background

Service users with psychosis may not consent to sharing information with
carers. However, carers require access to relevant information to support
them in their role.

Aims

To inform clinical practice when service users withhold consent to share
information with their carer.

Method

Study data were derived from a synthesis of policy review
(n=91), national survey (n=595) and
individual interviews (n=24).

Results

Key principles to guide information-sharing practices were identified.
Service users highlighted confidentiality being guaranteed by consent
processes. Carers suggested a ‘culture shift’ was required, with
professionals trained to work with carers. Professionals emphasised
mental capacity, professional judgement and the context of care. A best
practice framework is proposed.

Conclusions

An important distinction is between general information, which can always
be shared without consent, and personal information, which is new to the
carer and where consent needs to be considered. Clinical judgement is
central to balancing conflicting ethical imperatives in this area.
Neural correlates of the misattribution of speech in
schizophrenia
Authors: Allen Paul , Amaro Edson , Fu Cynthia H. Y. , Williams Steven C. R. , Brammer Michael J. , Johns Louise C. , McGuire Philip K.
Published: February 2007

Background

The neurocognitive basis of auditory verbal hallucinations is
unclear.

Aims

To investigate whether people with a history of such hallucinations would
misattribute their own speech as external and show differential
activation in brain areas implicated in hallucinations compared with
people without such hallucinations.

Method

Participants underwent functional magnetic resonance imaging (fMRI) while
listening to pre-recorded words. The source (self/non-self) and acoustic
quality (undistorted/distorted) were varied across trials. Participants
indicated whether the speech they heard was their own or that of another
person. Twenty people with schizophrenia (auditory verbal hallucinations
n=10, no hallucinations n=10) and
healthy controls (n=11) were tested.

Results

The hallucinator group made more external misattributions and showed
altered activation in the superior temporal gyrus and anterior cingulate
compared with both other groups.

Conclusions

The misidentification of self-generated speech in patients with auditory
verbal hallucinations is associated with functional abnormalities in the
anterior cingulate and left temporal cortex. This may be related to
impairment in the explicit evaluation of ambiguous auditory verbal
stimuli.
Hemodynamic Effects of Intravenous Fat Emulsion in an Animal Model of Severe Verapamil Toxicity Resuscitated with Atropine, Calcium, and Saline
Authors: Bania Theodore C. , Chu Jason , Perez Eric , Su Mark , Hahn In‐Hei
Published: February 2007

Background

Intravenous fat emulsion (IFE) decreases cardiotoxicity from several lipid‐soluble drugs, including verapamil.

Objectives

To verify if the addition of IFE to the standard treatment of severe verapamil toxicity would improve hemodynamics and survival.

Methods

Fourteen dogs were instrumented to measure systolic blood pressure, diastolic blood pressure, mean arterial pressure (MAP), heart rate, cardiac output, central venous pressures, left ventricular pressure changes over time, mixed venous oxygen saturation, pH, and base excess. Verapamil toxicity, defined as a 50% decrease in MAP, was induced with verapamil at 6 mg/kg/hr and maintained for 30 minutes by titrating the verapamil infusion rate. Following verapamil toxicity, the verapamil infusion rate was changed to 2 mg/kg/hr and continued for 90 minutes. All dogs were resuscitated with atropine (0.04 mg/kg intravenously) and calcium chloride (15 mg/kg intravenously every 5 minutes for three doses) and then randomized to receive either IFE (7 mg/kg of 20%) intravenously or equivalent volumes of 0.9% normal saline over 30 minutes. Measurements were recorded for 120 minutes by investigators blinded to the treatment. Data were analyzed using analysis of variance, survival analysis, and log‐rank test.

Results

Before the 30‐minute IFE or normal saline infusion, there were no differences in hemodynamic parameters. After IFE or normal saline infusion, the IFE‐treated group had higher MAP at 30 minutes (95% confidence interval [CI] = 5.6 to 44.7 mm Hg), 45 minutes (95% CI = 10.8 to 50.0 mm Hg), and 60 minutes (95% CI = 10.2 to 53.1 mm Hg). Kaplan–Meier 120‐minute survival rate was 14% (95% CI = 0.5% to 53%) for the saline group as compared with 100% (95% CI = 59% to 100%) for the IFE group (p = 0.01).

Conclusions

Standard resuscitation and IFE increase MAP and survival in an animal model of severe verapamil toxicity compared with standard resuscitation alone.
Embedding Medical Student Computer Tutorials into a Busy Emergency Department
Authors: Pusic Martin V. , Pachev George S. , MacDonald Wendy A.
Published: February 2007

Objectives

To explore medical students' use of computer tutorials embedded in a busy clinical setting; to demonstrate that such tutorials can increase knowledge gain over and above that attributable to the clinical rotation itself.

Methods

Six tutorials were installed on a computer placed in a central area in an emergency department. Each tutorial was made up of between 33 and 85 screens of information that include text, graphics, animations, and questions. They were designed to be brief (10 minutes), focused, interactive, and immediately relevant. The authors evaluated the intervention using quantitative research methods, including usage tracking, surveys of faculty and students, and a randomized pretest‐posttest study.

Results

Over 46 weeks, 95 medical students used the tutorials 544 times, for an overall average of 1.7 times a day. The median time spent on completed tutorials was 11 minutes (average [SD], 14 [±12] minutes). Seventy‐four students completed the randomized study. They completed 65% of the assigned tutorials, resulting in improved examination scores compared with the control (effect size, 0.39; 95% confidence interval = 0.15 to 0.62). Students were positively disposed to the tutorials, ranking them as “valuable.” Fifty‐four percent preferred the tutorials to small group teaching sessions with a preceptor. The faculty was also positive about the tutorials, although they did not appear to integrate the tutorials directly into their teaching.

Conclusions

Medical students on rotation in a busy clinical setting can and will use appropriately presented computer tutorials. The tutorials are effective in raising examination scores.
Inhibin A and B in Vitro Bioactivities Are Modified by Their Degree of Glycosylation and Their Affinities to Betaglycan
Authors: Makanji Yogeshwar , Harrison Craig A. , Stanton Peter G. , Krishna Radha , Robertson David M.
Published: February 2007

Inhibin A and B, important regulators of normal function in tissues of the reproductive axis, are glycosylated at either Asn268 or Asn268 and Asn302 in the α-subunit to produce 31- and 34-kDa isoforms, respectively. In this study, glycosylated isoforms of recombinant human inhibin A and B were purified from conditioned medium using immunoaffinity chromatography and reversed-phase HPLC. The masses of the purified inhibin preparations were determined by several inhibin immunoassays, and their in vitro bioactivities were based on suppression of FSH release by rat pituitary cells in culture. Based on a ratio of in vitro bioactivity to immunoactivity (B:I ratio), the monoglycosylated 31-kDa inhibin A was 5-fold more potent than the diglycosylated 34-kDa inhibin A (B:I ratio, 1.22 ± 0.15 vs. 0.24 ± 0.05; P < 0.001, respectively). The 31-kDa inhibin B was significantly (P < 0.001) more potent (1.75 ± 0.29) than the 34-kDa form (1.08 ± 0.20). Because inhibin biological activity is dependent upon interactions with the coreceptor betaglycan, the effect of inhibin glycosylation on betaglycan binding was assessed. Analogous to the pattern of in vitro bioactivity, 31-kDa inhibin A was 12-fold more active (IC50, 0.68 nm) than the 34-kDa isoform (IC50, 8.2 nm) at displacing [125I]inhibin A from COS7 cells expressing betaglycan. However, the 1.6-fold difference in bioactivity of the inhibin B isoforms was not matched by differences in their affinities for betaglycan. It is concluded that glycosylation of Asn302 of the α-subunit of inhibin A and B results in a decrease in bioactivity, and the effect on inhibin A, at least, is explained by its reduced affinity to betaglycan.
Prenatal and Postnatal Pathways to Obesity: Different Underlying Mechanisms, Different Metabolic Outcomes
Authors: Thompson Nichola M. , Norman Amy M. , Donkin Shawn S. , Shankar Ravi R. , Vickers Mark H. , Miles Jennifer L. , Breier Bernhard H.
Published: February 2007

Obesity and type 2 diabetes are worldwide health issues. The present paper investigates prenatal and postnatal pathways to obesity, identifying different metabolic outcomes with different effects on insulin sensitivity and different underlying mechanisms involving key components of insulin receptor signaling pathways. Pregnant Wistar rats either were fed chow ad libitum or were undernourished throughout pregnancy, generating either control or intrauterine growth restricted (IUGR) offspring. Male offspring were fed either standard chow or a high-fat diet from weaning. At 260 d of age, whole-body insulin sensitivity was assessed by hyperinsulinemic-euglycemic clamp, and other metabolic parameters were measured. As expected, high-fat feeding caused diet-induced obesity (DIO) and insulin resistance. Importantly, the insulin sensitivity of IUGR offspring was similar to that of control offspring, despite fasting insulin hypersecretion and increased adiposity, irrespective of postnatal nutrition. Real-time PCR and Western blot analyses of key markers of insulin sensitivity and metabolic regulation showed that IUGR offspring had increased hepatic levels of atypical protein kinase C ζ (PKC ζ) and increased expression of fatty acid synthase mRNA. In contrast, DIO led to decreased expression of fatty acid synthase mRNA and hepatic steatosis. The decrease in hepatic PKC ζ with DIO may explain, at least in part, the insulin resistance. Our data suggest that the mechanisms of obesity induced by prenatal events are fundamentally different from those of obesity induced by postnatal high-fat nutrition. The origin of insulin hypersecretion in IUGR offspring may be independent of the mechanistic events that trigger the insulin resistance commonly observed in DIO.
Variation in estradiol level affects cortical bone growth in response to mechanical loading in sheep
Authors: Devlin Maureen J. , Lieberman Daniel E.
Published: February 2007

Although mechanical loading can stimulate cortical bone growth, little is known about how individual physiology affects this response. This study demonstrates that in vivo variation in estradiol (E2)level alters osteoblast sensitivity to exercise-induced strains, affecting cortical bone responses to mechanical loading. Subadult sheep were divided into treatment groups that varied in terms of circulating E2 levels and loading (exercised and sedentary). After 45 days, periosteal cortical bone growth rates and cross-sectional properties were measured at the midshafts of hindlimb bones and compared with strain data. The results indicate significant interactions between E2 and strain. Cortical bone growth in exercised animals with elevated E2 levels was 27% greater in the femur, 6% greater in the tibia, and 14% greater in the metatarsal than in exercised animals with lower E2 levels, or sedentary animals regardless of E2 dose (P<0.05). There was also a trend toward greater resistance to deformation in the tibia, but not the metatarsal,in the exercised, high-E2 group compared to the other treatment groups. These results demonstrate that E2 plays a role in mediating skeletal responses to strain, such that physiological variation in E2 levels among individuals may lead to differential growth responses to similar mechanical loading regimes. Efforts to model the relationship between environmental strain and bone morphology should include the effects of physiological variation in hormone levels.
V-type H+-ATPase and Na+,K+-ATPase in the gills of 13 euryhaline crabs during salinity acclimation
Authors: Tsai Jyuan-Ru , Lin Hui-Chen
Published: February 2007

Because of their diverse habitats, crabs are excellent experimental species to study owing to the morphological changes and physiological adaptation that occur during their terrestrial invasion. Their hemolymphic osmoregulation in brackish water is crucial for a successful terrestrial invasion. Crabs can actively uptake or excrete ions upon salinity change, and the gills play a major role among the osmoregulatory organs. Several enzymes are involved in the osmoregulatory process, including Na+,K+-ATPase and V-type H+-ATPase (V-H+-ATPase). Na+,K+-ATPase is the driving force in establishing an ion gradient across the epithelial cell membrane in marine crabs. It has been reported that the osmoregulatory mechanisms in freshwater crabs are different from those in marine ones, suggesting that the driving force may come from V-H+-ATPase by generating the H+ ion gradient to facilitate the ion flow. Thirteen crab species from two families were used in this study. These crabs lived in five different habitats, including marine,intertidal, bimodal, freshwater and terrestrial habitats. The distribution of V-H+-ATPase in the 13 euryhaline crabs was revealed by histochemistry. V-H+-ATPase was localized in the apical region in crabs that could survive in the freshwater environment. We found that the freshwater and terrestrial crabs with stable Na+,K+-ATPase activity during salinity changes tended to have an apical V-H+-ATPase, whereas the intertidal ones with varying Na+,K+-ATPase activity showed a cytoplasmic V-H+-ATPase distribution. Finally, in Uca formosensis, a crab that had stable Na+,K+-ATPase activity, a significant difference in V-H+-ATPase activity between salinities was found. In conclusion, the hypothesis that V-H+-ATPase plays a crucial role in the freshwater adaptation of crabs is supported by our systemic investigation on 13 euryhaline crabs.
Non-invasive measurement of instantaneous forces during aquatic locomotion: a case study of the bluegill sunfish pectoral fin
Authors: Peng Jifeng , Dabiri John O. , Madden Peter G. , Lauder George V.
Published: February 2007

Swimming and flying animals generate unsteady locomotive forces by delivering net momentum into the fluid wake. Hence, swimming and flying forces can be quantified by measuring the momentum of animal wakes. A recently developed model provides an approach to empirically deduce swimming and flying forces based on the measurement of velocity and vortex added-mass in the animal wake. The model is contingent on the identification of the vortex boundary in the wake. This paper demonstrates the application of that method to a case study quantifying the instantaneous locomotive forces generated by the pectoral fins of the bluegill sunfish (Lepomis macrochirusRafinesque), measured using digital particle image velocimetry (DPIV). The finite-time Lyapunov exponent (FTLE) field calculated from the DPIV data was used to determine the wake vortex boundary, according to recently developed fluid dynamics theory. Momentum of the vortex wake and its added-mass were determined and the corresponding instantaneous locomotive forces were quantified at discrete time points during the fin stroke. The instantaneous forces estimated in this study agree in magnitude with the time-averaged forces quantified for the pectoral fin of the same species swimming in similar conditions and are consistent with the observed global motion of the animals. A key result of this study is its suggestion that the dynamical effect of the vortex wake on locomotion is to replace the real animal fin with an `effective appendage', whose geometry is dictated by the FTLE field and whose interaction with the surrounding fluid is wholly dictated by inviscid concepts from potential flow theory. Benefits and limitations of this new framework for non-invasive instantaneous force measurement are discussed, and its application to comparative biomechanics and engineering studies is suggested.
Orienting and avoidance turning are precisely computed by the predatory sea-slugPleurobranchaea californicaMcFarland
Authors: Yafremava Liudmila S. , Anthony Christopher W. , Lane Laura , Campbell Jessica K. , Gillette Rhanor
Published: February 2007

Computing the direction and amplitude of orienting and avoidance turns is fundamental to prey pursuit and risk avoidance in motile foragers. We examined computation of turns in the predatory sea-slug Pleurobranchaea californica, observing orienting and aversive turn responses to chemotactile stimuli applied to the chemosensory oral veil. We made seven observations: (1) the relation of turn angle/stimulus site on the oral veil was linear; (2) turn amplitudes increased with stimulus strength; (3) turn responses markedly overshot the target stimulus; (4) responses to two simultaneous stimuli at different loci were averaged to an intermediate angle;(5) stimuli could induce sequential turns in which the angles of the first and third turns were similar, a form of working memory; (6) turn direction was affected by appetitive state, so that animals with higher feeding thresholds tended to avoid appetitive stimuli; and (7) avoidance turns induced by mildly noxious stimuli were computed similarly to orienting, while differing in direction. These observations appear to outline a framework of behavior that could be employed for efficient tracking of odor trails, and which is regulated by decision mechanisms that integrate sensation, internal state and experience.
Influence of normal tyre forces on a vehicle's critical speed
Authors: Ivanov R P , Rousev R G , Ilchev P I
Published: February 2007

The paper presents a model and the results of theoretical and experimental research regarding the change in a vehicle's critical speed for different kinematic parameters of the turning motion. Six combinations of turning, braking, and longitudinal road inclinations are studied. The results show that in some cases a significant reduction in the critical speed in a curve takes place owing to the change in the normal tyre forces.
Castable composites and their application in automobiles
Authors: Mahendra K V , Radhakrishna K
Published: February 2007

Aluminium alloy based metal matrix composites (MMCs) have attracted attention in the automobile sector owing to ease of manufacturing, high specific strength properties, and better wear resistance. The stir casting or liquid metallurgy technique is the most economic and direct route for producing near-net-shape MMC components. In the present investigation, an Al-4.5%Cu alloy MMC with fly ash particles has been cast by the stir casting technique. Properties such as density, hardness, wear, and tensile and compression strength of the MMC have been evaluated. Further, to test the applicability of this composite as a bearing, a bush was prepared from the composite and tested under lubricated conditions for 200 h. The bush made from the composite showed more resistance to wear than the base alloy. A cylinder liner was cast from the composite and then tested in a two-stroke petrol engine. No seizure was observed even after 400 h of testing.
Extended arc thermal plasma assisted sintering of Al-Zr oxide composites
Authors: Ray M , Sahu D R , Mishra D K , Singh S K , Roul B K
Published: February 2007

An inexpensive and simple sintering technique using an extended arc thermal plasma assisted heating (EATPAH) source has been designed and fabricated for rapid sintering of Al x-Zr100- x ( X = 0, 10, 20,…, 100) oxide composites. High heat and mass transfer kinetics of thermal plasma assisted heating allows quick densification within a few minutes when compared with conventional heating source that takes tens of hours for identical densification. Sintering parameters such as sintering time, plasma power and plasmagen gas flowrate, and initial green density of composites are critically optimized. The green powder compacts sintered at a higher heating rate produced a sample with higher density and fine grain microstructure, whereas abnormal grain growth and lower density result at lower heating rate. This reveals that rapid sintering by EATPAH is effective for promoting the physical densification of the sintered end product. Hardness of the sintered products is studied to understand the density and shrinkage behaviour during plasma sintering. It is observed that highly dense sintered product with greater hardness and homogeneous phase distribution can be prepared within a few minutes by low cost EATPAH technique.
Household Expenditure and the Income Tax Rebates of 2001
Authors: Johnson David S , Parker Jonathan A , Souleles Nicholas S
Published: February 2007

Using questions expressly added to the Consumer Expenditure Survey, we estimate the change in consumption expenditures caused by the 2001 federal income tax rebates and test the permanent income hypothesis. We exploit the unique, randomized timing of rebate receipt across households. Households spent 20 to 40 percent of their rebates on nondurable goods during the three-month period in which their rebates arrived, and roughly two-thirds of their rebates cumulatively during this period and the subsequent three-month period. The implied effects on aggregate consumption demand are substantial. Consistent with liquidity constraints, responses are larger for households with low liquid wealth or low income.
In the Right Place at the Wrong Time: The Role of Firms and Luck in Young Workers' Careers
Authors: Wachter Till von , Bender Stefan
Published: February 2007

We examine administrative data on young German workers and their employers to study the long-term effects of an early career job loss. To account for nonrandom sorting of workers into firms with different turnover rates and for selective job mobility, we use changes over time in firm- and age-specific labor demand as an instrument for displacement. We find that wage losses of young job losers are initially 15 percent, but drop to zero within five years. Only workers leaving very large establishments suffer persistent losses. A comparison of estimators implies that initial sorting, negative selection, and voluntary job mobility biases ordinary least squares estimates toward finding permanent negative effects of early displacements.
Did Unilateral Divorce Laws Raise Divorce Rates? A Reconciliation and New Results
Authors: Wolfers Justin
Published: February 2007

Applying the Coase Theorem to marital bargaining suggests that shifting from consent to unilateral divorce laws will not affect divorce rates. I show that existing evidence suggesting large effects of divorce laws on divorce rates reflect a failure to explicitly model the dynamic response of divorce rates to a shock to the legal regime. When accounting for these dynamics, I find that unilateral divorce spiked following the adoption of unilateral divorce laws, but that this rise largely reversed itself within a decade. Overall, these changes in family law explain very little of the rise in divorce over the past half-century.
Phased-In Tax Cuts and Economic Activity
Authors: House Christopher L , Shapiro Matthew D
Published: February 2007

This paper uses a dynamic general equilibrium model to analyze and quantify the aggregate effects of the timing of tax rate changes enacted in 2001 (which called for successive rate reductions through 2006) and 2003 (which made immediate tax rate cuts scheduled for 2004 and 2006). The phased-in nature contributed to the slow recovery from the 2001 recession, while the elimination of the phase-in helped explain the increase in economic activity in 2003. The simulations suggest while the tax policy was a drag on the economy in 2001 and 2002, it increased economic growth in 2003, once phase-ins were eliminated.