bluuebunny/crossref_metadata_2025 huggingface dataset:
Performing Femininities: Listening to White Working‐Class Girls in Rural Maine
Authors: Brown Lyn Mikel
Published: April 2010

In this article, I explore the ways in which sixth, seventh, and eighth grade White girls from poor and working‐class families in rural Maine understand, express, and react to dominant cultural definitions of femininity. Using a qualitative method, The Listening Guide, to interpret data gathered over the course of a year from weekly videotaped focus group conversations and individual interviews, I identify and underscore the contradictory nature of what constitutes appropriately feminine discourse and behavior for these girls — discourse and behavior that is radically different from the dominant White middle‐class cultural ideal and that offers these girls a wide range of physical and verbal expression not usually considered under the rubric of conventional femininity. I then examine the girls' ambivalent relationship with middle‐class propriety, as well as their anger, their longing, and, in some cases, their resistance to dominant cultural ideologies of femininity. Although such resistance may serve them well in their local community, it puts them at odds with the expectations of their teachers and other adults invested in the conventional feminine ideal and thus underscores their displacement in school and society. The Listener's Guide, I contend, provides a way to elucidate the struggles these working‐class girls experience as they negotiate and contest contradictory voices and visions of appropriately feminine behavior and constructions of self vying for their attention and allegiance.
Using Feminist Research Methods to Understand the Friendships of Adolescent Boys‘
Authors: Way Niobe
Published: April 2010

Over the past 15 years, we have acquired a more complex understanding of the relational worlds of a socioeconomically and culturally diverse group of adolescent girls as a result of feminist, qualitative research. Yet we currently have little understanding of the relational experiences of an ethnically, socioeconomically, and culturally diverse group of adolescent boys. Using a feminist, voice‐centered approach to research, I sought to address this gap by exploring longitudinally the friendships of 19 urban, ethnically diverse adolescent boys from low‐income families. Results suggest that as these adolescents boys grow older, they grow increasingly distrustful of their male peers. Furthermore, by their latter‐year interviews, the boys spoke about not having close male friends because they did not trust their male peers. Many of the boys, however, yearned for close male friendships and recalled having had such relationships at an earlier age. Using feminist research methods with boys uncovered processes that have rarely been noted in the research literature on adolescent boys.
An Examination of the Constraints on Mutual Inquiry in a Participatory Action Research Project
Authors: Chataway Cynthia J.
Published: April 2010

Participatory Action Research (PAR) is designed to promote active involvement in every stage of the research process by those who are conventionally the focus of research. PAR thereby replaces the traditional hierarchical approach to research with a commitment to mutual inquiry and local ownership. The ideals of PAR have been much written about, but very little PAR literature actually describes how the research unfolded in any particular context, so this article examines the way that mutual inquiry manifested itself in a deeply divided Native community. In this setting, Native participants wanted to learn more about internal community problems and were interested in taking advantage of non‐Native time, research skills, and resources for that purpose. However, a history of oppression had left this community distrustful of outsiders (inhibiting mutual inquiry) and internally divided (inhibiting self‐inquiry). The use of PAR allowed a tenuous alliance to develop between myself as an English Canadian and the members of this Native community. Our particular modifications to the theoretical PAR model facilitated the coordinated participation of community groups that were resistant to working together in a research process that revealed barriers to change in the community and clarified directions for action. To achieve our goals, the PAR principles of mutuality and public responsibility were altered considerably from the prescriptions found in the PAR literature.
Minding the Gap: Positivism, Psychology, and the Politics of Qualitative Methods
Authors: Burman Erica
Published: April 2010

This article explores the politics and practices of qualitative research, in particular by interrogating the “gap” between qualitative and quantitative approaches to research. Two main claims are elaborated: first, that despite being recommended on grounds of ethical superiority (such as of nonmanipulation and instrumentality), qualitative research is not immune from such problems and may indeed harbor its own practices of exploitation; second, and correspondingly, that the moral high ground associated with qualitative research arises from the ways it is used rather than from any intrinsic features of the methodology. The argument is made that it is important to maintain this distinction in order to counter the tendency toward methodological fetishism so prevalent in scientistic (i.e., aspiring to “natural” scientific status) disciplines such as psychology. After framing these issues with some comments on the current popularity of qualitative methods, the article illustrates these claims by exploring 5 key ways that the positivist agenda of the discovery and control of a natural world can return in qualitative research, especially when this is mistakenly evaluated according to criteria formulated for quantitative analyses. The article concludes with a consideration of the epistemological and political status of attempts either to bridge or exacerbate the gap between qualitative and quantitative approaches.
Toward a History of Psychological Expertise
Authors: Harris Benjamin , Nicholson Ian A. M.
Published: April 2010

In honor of the 60th anniversary of SPSSI's founding, this issue examines the ascendence of psychological expertise in American society. After World War II, psychology grew as the public accepted the illuminating power and social benefits of psychologists' expert knowledge. In that period, four problems confronted psychological experts as their numbers and influence grew. First, they needed ideas and methods that were new and superior to common sense. Second, experts needed to appear both relevant and objective. Third, psychologists needed to forge alliances with those who held social power in the settings in which they wished to operate. Finally, experts needed to balance the roles of social critic and social engineer.
“Mapping the New Mental World Created by Radio”: Media Messages, Cultural Politics, and Cantril and Allport'sThe Psychology of Radio
Authors: Pandora Katherine
Published: April 2010

During the 1930s a number of interesting critiques of science and society emerged in the social sciences in general, and in psychology in particular. One example of this trend is The Psychology of Radio (1935), authored by Harvard psychologist Gordon Allport and his former student Hadley Cantril. The book, which was intended for both professional and lay audiences, sought to open discussion on the effects of the pervasive presence of radio, and to throw into relief the political, cultural, and economic contexts in which this new form of mass communication was embedded.
Social Action Research and the Commission on Community Interrelations
Authors: Cherry Frances , Borshuk Catherine
Published: April 2010

The Commission on Community Interrelations (CCI) was officially launched in 1945 by the American Jewish Congress (AJC) with Kurt Lewin as its chief consultant. Its intent was to bring research to bear on religious and racial discrimination. Espousing the ideals of democratic social engineering, CCI's action research projects aimed for scientific credibility and social utility. This article examines CCI's development from 1944 to 1952. By the early 1950s, changes within the AJC and in local communities and increased legal and mass protest strategies for racial justice as well as changes within social psychology as a subdiscipline challenged the viability of CCI's action research programs.
Exploring Thriving in the Context of Clinical Trauma Theory: Constructivist Self Development Theory
Authors: Saakvitne Karen W. , Tennen Howard , Affleck Glenn
Published: April 2010

In this article we critique current conceptualizations and methods of studying posttraumatic growth and offer an alternative framework using clinical trauma theory, specifically, Constructivist Self Development Theory (CSDT). We identify five limitations in the current literature: (1) a strict adherence to nomothetic investigation, (2) reliance on moderator analyses over descriptive inquiry, (3) exclusive use of univariate outcome indicators, (4) failure to distinguish effortful from automatic change, and (5) oversight of abrupt change. We offer CSDT as an integrative clinical theory that identifies five aspects of the self affected by traumatic events and examine how the study of thriving guided by CSDT could overcome these limitations. We conclude with a discussion of change, distinguishing that which occurs within psychotherapy from that which occurs outside the therapeutic context.
Embodying Psychological Thriving: Physical Thriving in Response to Stress
Authors: Epel Elissa S. , McEwen Bruce S. , Ickovics Jeannette R.
Published: April 2010

In addition to the context of psychological health, thriving can be measured in the context of physical health. Moreover, thriving may be ope rationalized at a macro level (e.g., improved functional health status following acute illness or injury) or at a micro level (e.g., hormonal balance). The goal of this article is to examine physical thriving at the micro level, by investigating hormonal responses to stressful situations. In addition, we examine the role that psychological factors play in this relationship. Although stress‐induced arousal has traditionally been viewed as negative, certain endocrine responses to stress can be health enhancing. Specifically, we propose that physical thriving results when there is a greater amount of growth promoting or anabolic hormones (e.g., growth hormone) than catabolic hormones (e.g., Cortisol). Characteristics of the stressor (duration, frequency, and controllability) as well as psychological moderators such as one's cognitive appraisal of the stressor (threat versus challenge) play a role in determining the profile of response to stress. When an individual appraises intermittent stressors as controllable, she or he may display a resilient profile of stress hormone responding—rapid Cortisol responses with quick recovery, and more importantly, Cortisol adaptation when faced with similar stressors over time. This stress response is in turn related to better health. To substantiate some of these issues, we present data from a study examining women's Cortisol reactivity in response to a repeated laboratory stressor and their self‐reported growth from facing trauma. The results suggest that women who have grown psychologically from trauma may show quicker Cortisol habituation to other stressors. Cortisol adaptation to stress may serve as one potential marker of resilient psychological and physical functioning.
Qualitative Approaches to the Study of Thriving: What Can Be Learned?
Authors: Massey Sean , Cameron Ann , Ouellette Suzanne , Fine Michelle
Published: April 2010

Using the data from two ongoing studies of resilience and thriving, one of gay men growing up in heterosexist environments, the other of women living with AIDS, we review how qualitative approaches have enabled researchers to grapple with conceptual, methodological, and ethical dilemmas related to the study of resilience and thriving. We discuss the implications our values as researchers have on determining who is thriving; the powerful social, cultural, and political contexts that must be considered when investigating the effects of and resistance to adversity; and the implications of conceptualizing thriving as a process. Finally, we consider the opportunities opened up by qualitative analysis and suggest some avenues for future research.
Situational Power and Interpersonal Dominance Facilitate Bias and Inequality
Authors: Goodwin Stephanie A. , Operario Don , Fiske Susan T.
Published: April 2010

A model is proposed that describes interpersonal phenomena that maintain inter‐group hierarchies and conflict. Situational control and interpersonal dominance are identified as conditions that promote motives to stereotype, leading to cognitive and judgment biases that cumulatively reinforce the status quo. Three general hypotheses are derived from the model. First, powerholders are predicted to use attention strategies that favor stereotype maintenance, stereotyping subordinates by default (ignoring counterstereotypic information) and by design (increasing attention to stereotypic information). Second, high‐dominance perceivers are predicted to respond with the same cognitive biases as people with situational power. Finally, power and dominance are predicted independently to facilitate bias in explicit judgments. Results from our research program support the hypotheses. Implications for future change are discussed.
The Interface Between Ethnic and Social System Attachment: The Differential Effects of Hierarchy‐Enhancing and Hierarchy‐Attenuating Environments
Authors: Sinclair Stacey , Sidanius Jim , Levin Shana
Published: April 2010

Social dominance theory distinguishes between hierarchy‐enhancing environments, which promote inequality between groups (e.g., American society), and hierarchy‐attenuating environments, which promote equality between groups (e.g., universities). Consistent with predictions derived from this distinction, a panel study that assessed attitudes prior to university exposure and after one year of university exposure yielded three findings: (1) exposure to the university decreased antiegalitarian attitudes; (2) at the end of their first year of college, European Americans exhibited greater national attachment than Asian Americans, Latinos, and African Americans, but members of all groups exhibited similar levels of university attachment; and (3) European Americans exhibited a more positive association between ethnic attachment and national attachment than members of the other three groups, but members of all groups exhibited similar relationships between ethnic attachment and university attachment.
Electrocardiographic Differentiation between Acute Pulmonary Embolism and Non‐ST Elevation Acute Coronary Syndromes at the Bedside
Authors: Jankowski Krzysztof , Kostrubiec Maciej , Ozdowska Patrycja , Milanowska‐Puncewicz Blanka , Pacho Szymon , Pedowska‐Włoszek Justyna , Kaczyńska Anna , Łabyk Andrzej , Hrynkiewicz Anna , Pruszczyk Piotr
Published: April 2010

Background: Clinical picture of acute pulmonary embolism (APE), with wide range of electrocardiographic (ECG) abnormalities can mimic acute coronary syndromes.

Objectives: Assessment of standard 12‐lead ECG usefulness in differentiation at the bedside between APE and non‐ST elevation acute coronary syndrome (NSTE‐ACS).

Methods: Retrospective analysis of 143 patients: 98 consecutive patients (mean age 63.4 ± 19.4 year, 45 M) with APE and 45 consecutive patients (mean age 72.8 ± 10.8 year, 44 M) with NSTE‐ACS. Standard ECGs recorded on admission were compared in separated groups.

Results: Right bundle branch block (RBBB) and S1S2S3 or S1Q3T3 pattern were found in similar frequency in both groups (10 [11%] APE patients vs 6 [14%] NSTE‐ACS patients, 27 [28%] patients vs 7 [16%] patients, respectively, NS). Negative T waves in leads V1‐3 together with negative T waves in inferior wall leads II, III, aVF (OR 1.3 [1.14–1.68]) significantly indicated APE with a positive predictive value of 85% and specificity of 87%. However, counterclockwise axis rotation (OR 4.57 [2.74–7.61]), ventricular premature beats (OR 2.60 [1.60–4.19]), ST depression in leads V1‐3 (OR 2.25 [1.43–3.56]), and negative T waves in leads V5‐6 (OR 2.08 [1.31–3.29]) significantly predicted NSTE‐ACS.

Conclusions: RBBB, S1S2S3, or S1Q3T3 pattern described as characteristic for APE were not helpful in the differentiation between APE and NSTE‐ACS in studied group. Coexistence of negative T waves in precordial leads V1‐3 and inferior wall leads may suggest APE diagnosis.

Ann Noninvasive Electrocardiol 2010;15(2):145–150
Cardiac Arrhythmias Triggered by Sudden and Dynamic Efforts
Authors: Furtado Emanuel C. , Araújo Claudio Gil S.
Published: April 2010

Background: Some arrhythmias are triggered only during exercise. The aim of this study is to describe the frequency and type of arrhythmia induced by a standardized protocol of sudden and dynamic exercise, which tends to reflect routine situations of efforts (e.g., climbing stairs), and compare with those found on maximal cardiopulmonary exercise test (CPET).

Methods: A total of 2329 subjects (1594 men) aged 9–91 years (mean 52 years, SD ± 16) were submitted to a standardized protocol of sudden and dynamic exercise (4‐second exercise test [4sET]) prior to a CPET. A continuous digital electrocardiogram (ECG) was recorded during 4sET and CPET, and later reviewed and interpreted by the same physician (who supervised all the procedures).

Results: A total of 1125 subjects (43%) had cardiac arrhythmias during one or both procedures. About 57% of the arrhythmias were supraventricular, but 47 subjects (2% of all subjects) presented more complex arrhythmias including 43 cases of nonsustained supraventricular tachycardia and four nonsustained ventricular tachycardia. While arrhythmias were more often exposed by the CPET (P < 0.01), in 221 cases (10% of the total sample) of arrhythmias they were only induced by 4sET; these included four cases of nonsustained supraventricular tachycardia.

Conclusion: 4sET‐induced arrhythmias tend to be simple and were always short‐lasting. In some cases, ECG recording during 4sET showed arrhythmias that would not be induced by a progressive maximal exercise test. Different situations of exercise, sudden and short versus maximal and progressive, tend to generate different arrhythmic responses and possibly complementary clinical implications.

Ann Noninvasive Electrocardiol 2010;15(2):151–156
Defects, Structure Changes, and the Effect of Random Fields on the Displacement of Off‐Center Ions in Sr0.5Ba0.5Nb2O6 Doped with Combinations of Ce and Cr
Authors: Fang Tsang‐Tse , Chung Han‐Yang , Lee Chih‐Hao
Published: April 2010

Synchrotron X‐ray powder diffraction data are analyzed in detail by the Rietveld structure refinement program to obtain microscopic structure changes of Sr0.5Ba0.5Nb2O6 (SBN50) doped with combinations of Ce and Cr. The defects of Ce and (Ce,Cr)‐doped SBN50 are determined by the densification behavior, and it is found that creation of Nb vacancies and self‐compensation are the defect reactions for Ce and (Ce, Cr) dopants, respectively. The variations of the lattice parameters of a and c axes with doping content are determined by the changes of the distance between A1 and A2 sites via Coulomb interactions and the mean bond length of Nb(1)–O(4), respectively. It is confirmed that the polarization of SBN50 is mainly determined by the displacement of Nb ions. The effect of random fields induced by the impurities of the combinations of Ce and Cr on the displacement of off‐center Nb ions has been reasonably explained.
ZrB2 Powders Synthesis by Borothermal Reduction
Authors: Ran Songlin , Van der Biest Omer , Vleugels Jef
Published: April 2010

High‐purity zirconium diboride (ZrB2) powders with submicrometer particle size were synthesized by borothermal reduction of nanometric ZrO2 powders in vacuum. The reaction process was experimentally and thermodynamically assessed. B2O3 was identified as a possible intermediate reaction product. ZrO2 completely converted to ZrB2 when thermally treated at 1000°C for 2 h in a vacuum, but the removal of residual boron‐related species required a temperature above 1500°C. ZrB2 powders obtained at 1000°–1200°C showed a faceted morphology, whereas those prepared above 1500°C had a nearly spherical morphology. The particle size that was calculated from the measured surface area increased with the increasing synthesis temperature from 0.15 μm at 1000°C to 0.66 μm at 1650°C. The oxygen content of the ZrB2 powders synthesized at 1650°C was as low as 0.43 wt%.
Spatio‐temporal modelling ofGlossina palpalis gambiensisandGlossina tachinoidesapparent densities in fragmented ecosystems of Burkina Faso
Authors: Sedda Luigi , Guerrini Laure , Bouyer Jérémy , Koné Naférima , Rogers David J.
Published: April 2010

Tsetse are the insect vectors of the African trypanosomiases. As with many diseases, transmission of trypanosomiasis varies through space and time. Capturing the variation of both vector and disease has, in the past, been attempted separately in the space and time dimensions, usually using deterministic techniques. Very few efforts have used space‐time covariation and have hence missed any correlations that may exist between variation in these two dimensions.

Here we propose two novel approaches to space‐time analysis derived from space‐time geostatistics in a kriging framework. The approaches were developed through analysis of a dataset recording the Apparent Density ofGlossina palpalis gambiensisandGlossina tachinoides(Diptera: Glossinidae) in three riparian sites in Burkina Faso over 15 months between 2006 and 2007. This site is fragmented due to human activity in the area.

The first approach, Space Time Ordinary Kriging, does not consider the effect of fragmentation. It is used as a benchmark to test the increased explanatory power of the second method, which does account for fragmentation. The second method, Regression Space Time Simple Kriging, is a distinct improvement over the first approach because it allows for a spatial trend in the mean trap catch; this trend is related to, and later predicted from, environmental co‐variates.

The results indicate the presence of space and time effects on tsetse distribution, dependent on the size of the habitat fragmentation patches. These effects occur at relatively small geographic scales within a season. Whilst such variation has long been suspected, the new methods presented here are able to quantify this variation precisely, so that seasonal and spatial comparisons can now be made both within and between species.
The influence of diet on foraging habitat models: a case study using nursing Antarctic fur seals
Authors: Casper Ruth M. , Sumner Michael D. , Hindell Mark A. , Gales Nicholas J. , Staniland Iain J. , Goldsworthy Simon D.
Published: April 2010

Predictable sources of food underpin lifetime reproductive output in long lived animals. The most important foraging areas of top marine predators are therefore likely to be related to environmental features that enhance productivity in predictable spatial and temporal patterns. Even so, although productive areas within the marine environment are distributed patchily in space and time, most studies assess the relationships between feeding activity and proximate, not long term, environmental characteristics. In addition, individuals within a population may exploit different prey types, and these are often associated with different hydrographic features. Until now, models attempting to associate core foraging areas (CFAs) of marine predators with the environmental characteristics of those areas have not considered the diet of individual animals, despite the influence this could have on these relationships. We used bathymetry and multi‐year (n=24) mean sea surface temperature and variability as predictors of CFAs of lactating Antarctic fur seals Arctocephalus gazella at Heard Island. The effect of prey types on the predictability of these models was explored by matching diet and foraging trip data of individual seals (n=40 seals, n=1 trip each). Differences in diet between seals were mirrored by their spatial behaviour. Foraging strategies differed both between and within groups of seals consuming different diets. Long‐term environmental parameters were useful for predicting the foraging activity of seals that consumed a single prey type with relatively specific habitat preferences, but not for those that consumed single or multiple prey types associated with more varied habitats. Ignoring individual variation in predator diet probably contributes to the poor performance of foraging habitat models. These findings highlight the importance of incorporating individual specialization in foraging behaviour into ecological models and management of predator populations.
Epigenetic regulation of serotonin transporter expression and behavior in infant rhesus macaques
Authors: Kinnally E. L. , Capitanio J. P. , Leibel R. , Deng L. , LeDuc C. , Haghighi F. , Mann J. J.
Published: April 2010

Epigenetic mechanisms may moderate genetic and environmental risk (G×E) for mood disorders. We used an experimental rhesus macaque model of early life stress to test whether epigenetic regulation of serotonin transporter (5‐HTT) may contribute to G×E interactions that influence behavior and emotion. We hypothesized that peripheral blood mononuclear cell (PBMC) DNA methylation within an 800 bp cytosine–phosphate–guanosine (CpG) island that overlaps with the 5‐HTT transcription initiation start site, a hypothesized model of the same genomic region in brain tissue, would mediate or moderate the effects of early life stress and a functional 5‐HTT promoter polymorphism (rh5‐HTTLPR) on two outcomes: PBMC 5‐HTT expression and behavioral stress reactivity. Eighty‐seven infant rhesus macaques (3–4 months of age) were either mother reared in large social groups (n = 70) or nursery reared (n = 17). During a maternal/social separation, infants' blood was sampled and behavioral stress reactivity recorded. PBMC DNA and RNA samples were used to determine rh5‐HTTLPR genotype, 5‐HTT mRNA expression using quantitative reverse transcription polymerase chain reaction (qRT‐PCR) and 5‐HTT CpG methylation status using sodium bisulfite pyrosequencing. Consistent with human data, carriers of the low‐expressing rh5‐HTTLPR alleles exhibited higher mean 5‐HTT CpG methylation, which was associated with lower PBMC 5‐HTT expression. Higher 5‐HTT CpG methylation, but not rh5‐HTTLPR genotype, exacerbated the effects of early life stress on behavioral stress reactivity in infants. 5‐HTT CpG methylation may be an important regulator of 5‐HTT expression early in development and may contribute to the risk for mood disorders observed in ‘high‐risk’5‐HTTLPR carriers.
Whose middle is it anyway? Why universal welfare matters
Authors: Horton Tim , Gregory James
Published: April 2010

Tim Horton and James Gregory consider why in this general election the battle for the middle will illuminate perhaps the most important left‐right strategic battle for a century or more: the battle to define the very nature of our welfare state
An affordability crisis in schools?
Authors: Farthing Rys
Published: April 2010

Tackling family poverty is essential to addressing the crisis in school affordability and reducing the educational divide, says Rys Farthing
Dark matter haloes determine the masses of supermassive black holes
Authors: Booth C. M. , Schaye Joop
Published: April 2010

The energy and momentum deposited by the radiation from accretion flows on to the supermassive black holes (BHs) that reside at the centres of virtually all galaxies can halt or even reverse gas inflow, providing a natural mechanism for supermassive BHs to regulate their growth and to couple their properties to those of their host galaxies. However, it remains unclear whether this self-regulation occurs on the scale at which the BH is gravitationally dominant, on that of the stellar bulge, the galaxy or that of the entire dark matter halo. To answer this question, we use self-consistent simulations of the co-evolution of the BH and galaxy populations that reproduce the observed correlations between the masses of the BHs and the properties of their host galaxies. We first confirm unambiguously that the BHs regulate their growth: the amount of energy that the BHs inject into their surroundings remains unchanged when the fraction of the accreted rest mass energy that is injected is varied by four orders of magnitude. The BHs simply adjust their masses so as to inject the same amount of energy. We then use simulations with artificially reduced star formation rates to demonstrate explicitly that BH mass is not set by the stellar mass. Instead, we find that it is determined by the mass of the dark matter halo with a secondary dependence on the halo concentration, of the form that would be expected if the halo binding energy were the fundamental property that controls the mass of the BH. We predict that the BH mass, mBH, scales with halo mass as mBH∝mαhalo, with α≈ 1.55 ± 0.05, and that the scatter around the mean relation in part reflects the scatter in the halo concentration–mass relation.
The Treatment of Cognitive Impairment Associated with Parkinson's Disease
Authors: Burn David J.
Published: April 2010

Cognitive impairment and dementia associated with Parkinson's disease (PD) are common and often have devastating effects upon the patient and their family. Early cognitive impairment in PD is frequent, and the functional impact may be underestimated. Optimal management will rely upon better identification of the predominant symptoms and greater knowledge of their pathophysiological basis. The management of dementia in PD (PD‐D) also has to consider the significant neuropsychiatric burden that frequently accompanies the cognitive decline, as well as fluctuations in attention. Atypical anti‐psychotics have a limited role at present in treating PD‐D, although new drugs are under development. The mainstay of drug management for people with PD‐D is cholinesterase inhibitors, although recent trials have suggested that the N‐methyl‐D aspartate antagonist memantine may also have some benefit. Disease modification remains the ultimate goal for preventing the inexorable decline in PD‐D, although effective interventions are still some way off. Limited benefit may, however, be possible through exercise programmes and so‐called “medical foods”, although randomised trials are required to confirm largely anecdotal observations.
Neuroimaging and Cognition in Parkinson's Disease Dementia
Authors: Silbert Lisa C. , Kaye Jeffrey
Published: April 2010

The prevalence of cognitive impairment and dementia in Parkinson's disease (PD) is high and can potentially occur as the result of multiple differing pathologies. Neuroimaging has provided evidence of decreased cortical volume, increased white matter diffusion changes, and decreased resting metabolic activity that appears to begin prior to the onset of dementia in PD patients. Cognitive impairment has been found to be associated with multiple neurotransmitter transmission deficiencies, including dopamine and acetylcholine, indicating a widespread neurotransmitter dysfunction in PD‐related dementia. Findings of increased Pittsburgh Compound B (PiB) binding in subjects with Lewy Body Disease (LBD) compared with Parkinson's disease and dementia (PDD) may explain phenotype differences in the spectrum of Dementia with Lewy Bodies (DLB), and show promise in guiding future therapeutic trials aimed at this disease. Advances in neuroimaging now allow for the detection of volumetric, pharmacologic, and pathological changes that may assist in the diagnosis and prediction of cognitive impairment in Parkinson's patients so that better evaluation of disease progression and treatment can be obtained.
Pathologic Correlates of Dementia in Individuals with Lewy Body Disease
Authors: Sonnen Joshua A. , Postupna Nadia , Larson Eric B. , Crane Paul K. , Rose Shannon E. , Montine Kathleen S. , Leverenz James B. , Montine Thomas J.
Published: April 2010

Cognitive impairment and dementia are more common in patients with Parkinson disease (PD) than age‐matched controls and appear to become more frequent as PD progresses. However, estimates of dementia in patients with PD have varied widely, likely due in part to differences in case definition, case ascertainment and methodology. First, we review investigations of usual pathologic correlates of dementia in patients with brainstem (b) Lewy Body Disease (LBD) and report our findings from the initial 266 brain autopsies from a population‐based study of brain aging and incident dementia. Our results showed that 2.6% of subjects were diagnosed with PD during life but that 20% had bLBD at autopsy. Seventy percent of individuals with bLBD had high level of one or more cerebral pathologic changes significantly associated with dementia: Alzheimer's disease (AD), cerebral (c) LBD or microvascular brain injury (µVBI); these were commonly co‐morbid. Next we consider proposed contributors to cognitive impairment and dementia in the approximately 30% of patients with only bLBD, including regionally selective dendritic degeneration of neostriatal medium spiny neurons. Diseases contributing to cognitive impairment and dementia in patients with bLBD are heterogeneous, providing diagnostic challenges as well as multiple opportunities for successful intervention in patients with PD.
Effects of Tip Clearance and Casing Recess on Heat Transfer and Stage Efficency in Axial Turbines
Authors: Ameri A. A. , Steinthorsson E. , Rigby D. L.
Published: April 2010

Calculations were performed to assess the effect of the tip leakage flow on the rate of heat transfer to blade, blade tip, and casing. The effect on exit angle and efficiency was also examined. Passage geometries with and without casing recess were considered. The geometry and the flow conditions of the GE-E3 first-stage turbine, which represents a modern gas turbine blade, were used for the analysis. Clearance heights of 0, 1, 1.5, and 3 percent of the passage height were considered. For the two largest clearance heights considered, different recess depths were studied. There was an increase in the thermal load on all the heat transfer surfaces considered due to enlargement of the clearance gap. Introduction of recessed casing resulted in a drop in the rate of heat transfer on the pressure side, but the picture on the suction side was found to be more complex for the smaller tip clearance height considered. For the larger tip clearance height, the effect of casing recess was an orderly reduction in the suction side heat transfer as the casing recess height was increased. There was a marked reduction of heat load and peak values on the blade tip upon introduction of casing recess; however, only a small reduction was observed on the casing itself. It was reconfirmed that there is a linear relationship between the efficiency and the tip gap height. It was also observed that the recess casing has a small effect on the efficiency but can have a moderating effect on the flow underturning at smaller tip clearances.
Mach Number Effects on Turbine Blade Transition Length Prediction
Authors: Boyle R. J. , Simon F. F.
Published: April 2010

The effect of a Mach number correction on a model for predicting the length of transition was investigated. The transition length decreases as the turbulent spot production rate increases. Many of the data for predicting the spot production rate come from low-speed flow experiments. Recent data and analysis showed that the spot production rate is affected by Mach number. The degree of agreement between analysis and data for turbine blade heat transfer without film cooling is strongly dependent on accurately predicting the length of transition. Consequently, turbine blade heat transfer data sets were used to validate a transition length turbulence model. A method for modifying models for the length of transition to account for Mach number effects is presented. The modification was made to two transition length models. The modified models were incorporated into the two-dimensional Navier–Stokes code, RVCQ3D. Comparisons were made between predicted and measured midspan surface heat transfer for stator and rotor turbine blades. The results showed that accounting for Mach number effects significantly improved the agreement with the experimental data.
Measurement and Computation of Energy Separation in the Vortical Wake Flow of a Turbine Nozzle Cascade
Authors: Carscallen W. E. , Currie T. C. , Hogg S. I. , Gostelow J. P.
Published: April 2010

This paper describes the observation, measurement, and computation of vortex shedding behind a cascade of turbine nozzle guide vanes that have a blunt trailing edge. At subsonic discharge speeds, periodic wake vortex shedding was observed at all times at a shedding frequency in the range 7–11 kHz. At high subsonic speeds the wake was susceptible to strong energy redistribution. The effect was greatest around an exit Mach number of 0.95 and results are presented for that condition. An unusually cold flow on the wake centerline and hot spots at the edges of the wake were measured. These were found to be a manifestation of Eckert–Weise effect energy separation in the shed vortex street. Experimental identification of these phenomena was achieved using a new stagnation temperature probe of bandwidth approaching 100 kHz. Using phase-averaging techniques, it was possible to plot contours of time-resolved entropy increase at the downstream traverse plane. Computational work has been undertaken that gives qualitative confirmation of the experimental results and provides a more detailed explanation of the fine scale structure of the vortex wake. The topology of the wake vortical structures behind blunt trailing-edged turbine blades is becoming clearer. These measurements are the first instantaneous observations of the energy separation process occurring in turbine blade wake flows. This was also the first demonstration of the use of the probe in the frequency, Mach number, and temperature ranges typical of operation behind the rotors of high-performance turbomachines such as transonic fans.
A Numerical Study of the Influence of Grid Refinement and Turbulence Modeling on the Flow Inside a Highly Loaded Turbine Cascade
Authors: Hilderbrandt T. , Fottner L.
Published: April 2010

A thorough numerical study was conducted to simulate the flow field inside a highly loaded linear turbine cascade. The numerical investigation was focused on the secondary flow field as well as on the prediction of the overall design goals within reasonable accuracy limits. The influence of grid resolution was investigated in order to obtain detailed information about the requirements of a grid-independent solution. Three different two-equation turbulence models were applied to two numerical grids of different resolution. Emphasis was laid on separating the influences of grid resolution and turbulence models. The Mach and Reynolds numbers as well as the level of free-stream turbulence were set to values typical of turbomachinery conditions. The computational study was carried out using a three-dimensional state-of-the-art block structured Navier–Stokes solver. The comparison of the numerical results with experiments clearly revealed the different degree of agreement between simulation and measurement. This paper describes the application of a modern flow solver to a test case that is relevant for practical turbomachinery design purposes. The agreement between the experiments and the results of the numerical study is good and in most cases well within the accuracy limits proposed by Strazisar and Denton (1995). It was found out that the main effect on the quality of the computations is the resolution of the numerical grid. The finest grid used reached over one million points halfspan, showing clearly superior results compared with a coarser, though still fine grid. The influence of different turbulence models on the numerically obtained flow field was relatively small in comparison with the grid influence.
Viscous and Inviscid Linear/Nonlinear Calculations Versus Quasi-Three-Dimensional Experimental Cascade Data for a New Aeroelastic Turbine Standard Configuration
Authors: Fransson T. H. , Jo¨cker M. , Bo¨lcs A. , Ott P.
Published: April 2010

This paper presents a new International Standard Configuration to be added to an already existing set of 10 configurations for unsteady flow through vibrating axial-flow turbomachine cascades. This 11th configuration represents a turbine blade geometry with transonic design flow conditions with a normal shock positioned at 75 percent real chord on the suction side. Out of a set of test cases covering all relevant flow regimes two cases were selected for publication: A subsonic, attached flow case, and an off-design transonic case showing a separation bubble at 30 percent real chord on the suction side. The performed tests are shown to be repeatable and suitable for code validations of numerical models predicting flutter in viscous flows. The validity of the measured data of the two public cases was examined and comparisons with other tests were conducted. Sometimes a large difference in aerodynamic damping was observed on cases with similar flow conditions. This was investigated at three transonic cases with almost identical inlet flow conditions and only small variations in outlet Mach number. It was found that the differences in the global damping are due to very local changes on the blade surface in the shock region, which obtain a large influence by the integration because of the discrete measuring points. Hence it is recommended not to look at the global damping for code validations but more precisely to the local values. These show a common tendency, which is reproducible with different numerical methods. This was demonstrated with a potential model, a linear Euler model, a nonlinear Euler model, and a Navier–Stokes solver, all applied to predict flutter of each test case with a 2D/Q3D approach. This paper demonstrates both the limitations of inviscid codes to predict flutter in viscous flow regimes, and their cost advantage in attached flow calculations. The need for viscous code development and validation is pointed out. This should justify and encourage the publication of thoroughly measured test cases with viscous effects.
A Computational Model for Short-Wavelength Stall Inception and Development in Multistage Compressors
Authors: Gong Y. , Tan C. S. , Gordon K. A. , Greitzer E. M.
Published: April 2010

This paper presents a computational model for simulating axial compressor stall inception and development via disturbances with length scales on the order of several (typically about three) blade pitches. The model was designed for multistage compressors in which stall is initiated by these “short-wavelength” disturbances, also referred to as spikes. The inception process described is fundamentally nonlinear, in contrast to the essentially linear behavior seen in so-called “modal stall inception”. The model was able to capture the following experimentally observed phenomena: (1) development of rotating stall via short-wavelength disturbances, (2) formation and evolution of localized short-wavelength stall cells in the first-stage of a mismatched compressor, (3) the switch from long to short-wavelength stall inception resulting from the re-staggering of the inlet guide vane, (4) the occurrence of rotating stall inception on the negatively sloped portion of the compressor characteristic. Parametric investigations indicated that: (1) short-wavelength disturbances were supported by the rotor blade row, (2) the disturbance strength was attenuated within the stators, and (3) the reduction of inter-blade row gaps can suppress the growth of short-wavelength disturbances. It is argued that each local component group (rotor plus neighboring stators) has its own instability point (i.e., conditions at which disturbances are sustained) for short-wavelength disturbances, with the instability point for the compressor set by the most unstable component group.
Tip-Clearance and Secondary Flows in a Transonic Compressor Rotor
Authors: Gerolymos G. A. , Vallet I.
Published: April 2010

The purpose of this paper is to investigate tip-clearance and secondary flows numerically in a transonic compressor rotor. The computational method used is based on the numerical integration of the Favre-Reynolds-averaged three-dimensional compressible Navier–Stokes equations, using the Launder–Sharma near-wall k–ε turbulence closure. In order to describe the flowfield through the tip and its interaction with the main flow accurately, a fine O-grid is used to discretize the tip-clearance gap. A patched O-grid is used to discretize locally the mixing-layer region created between the jetlike flow through the gap and the main flow. An H–O–H grid is used for the computation of the main flow. In order to substantiate the validity of the results, comparisons with experimental measurements are presented for the NASA_37 rotor near peak efficiency using three grids (of 106, 2 X 106, and 3 X 106 points, with 21, 31, and 41 radial stations within the gap, respectively). The Launder–Sharma k–ε model underestimates the hub corner stall present in this configuration. The computational results are then used to analyze the interblade-passage secondary flows, the flow within the tip-clearance gap, and the mixing downstream of the rotor. The computational results indicate the presence of an important leakage-interaction region where the leakage-vortex after crossing the passage shock-wave mixes with the pressure-side secondary flows. A second trailing-edge tip vortex is also clearly visible.
Investigation of Discrete-Hole Film Cooling Parameters Using Curved-Plate Models
Authors: Berthe M. K. , Patankar S. V.
Published: April 2010

Computations have been conducted on curved, three-dimensional discrete-hole film cooling geometries that included the mainflow, injection hole, and supply plenum regions. Both convex and concave film cooling geometries were studied. The effects of several film cooling parameters have been investigated, including the effects of blowing ratio, injection angle, hole length, hole spacing, and hole staggering. The blowing ratio was varied from 0.5 to 1.5, the injection angle from 35 to 65 deg, the hole length from 1.75D to 6.0D, and the hole spacing from 2D to 3D. The staggered-hole arrangement considered included two rows. The computations were performed by solving the fully elliptic, three-dimensional Navier–Stokes equations over a body-fitted grid. Turbulence closure was achieved using a modified k–ε model in which algebraic relations were used for the turbulent viscosity and the turbulent Prandtl number. The results presented and discussed include plots of adiabatic effectiveness as well as plots of velocity contours and velocity vectors in cross-stream planes. The present study reveals that the blowing ratio, hole spacing, and hole staggering are among the most significant film cooling parameters. Furthermore: (1) The optimum blowing ratios for curved surfaces are higher than those for flat surfaces, (2) a reduction of hole spacing from 3D to 2D resulted in a very significant increase in adiabatic effectiveness, especially on the concave surface, (3) the increase in cooling effectiveness with decreasing hole spacing was found to be due to not only the increased coolant mass per unit area, but also the smaller jet penetration and the weaker counterrotating vortices, (4) for all practical purposes, the hole length was found to be a much less significant film cooling parameter.