bluuebunny/crossref_metadata_2025 huggingface dataset:
Why Anticyclones Can Split
Authors: Drijfhout S. S.
Published: February 2011

The question of whether anticyclones can split and break up is readdressed using a numerical, multilayer, primitive equation model. Applying the conservation of integrated angular momentum (IAM) to barotropic and baroclinic vortices, it has been argued that anticyclones can never split, no matter what their structure is. When an anticyclone splits, the IAM has to increase as the newly formed eddies are pushed away from their original center. Conservation of IAM prohibits such an increase. Several numerical simulations, however, have shown anticyclonic splitting. In a multilayer model, a vertical transport of IAM is possible. For counterrotating eddies (an anticyclone on top of a cyclone) it is easy to see that a vertical exchange of IAM allows the eddy to break up. For a compensated or weakly corotating eddy, breakup is only possible when, in addition to a vertical transport of IAM, in the deep layer(s) IAM is exchanged between the core of the vortex and the surrounding fluid. In the presence of a tilting interface, the pressure gradient associated with the sea surface height (SSH) anomaly, in particular its non-equivalent-barotropic part, drives the required exchanges. The non-equivalent-barotropic SSH anomaly is associated with the vertical phase lag of the most unstable eigenmode (m = 2), which develops when this mode gains energy by baroclinic energy conversion. The previous conclusion that anticyclones cannot split on their own should be revised to the following: anticyclones cannot split by barotropic processes alone—baroclinic instability is a necessary ingredient for splitting to occur.
Turbulent Mixing in the Red Sea Outflow Plume from a High-Resolution Nonhydrostatic Model
Authors: Özgökmen Tamay M. , Johns William E. , Peters Hartmut , Matt Silvia
Published: February 2011

Given the motivation that overflow processes, which supply source waters for most of the deep and intermediate water masses in the ocean, pose significant numerical and dynamical challenges for ocean general circulation models, an intercomparison study is conducted between field data collected in the Red Sea overflow and a high-resolution, nonhydrostatic process model. The investigation is focused on the part of the outflow that flows along a long narrow channel, referred to as the “northern channel,” that naturally restricts motion in the lateral direction such that the use of a two-dimensional model provides a reasonable approximation to the dynamics. This channel carries about two-thirds of the total Red Sea overflow transport, after the overflow splits into two branches in the western Gulf of Aden. The evolution of the overflow in the numerical simulations can be characterized in two phases: the first phase is highly time dependent, during which the density front associated with the overflow propagates along the channel. The second phase corresponds to that of a statistically steady state. The primary accomplishment of this study is that the model adequately captures the general characteristics of the system: (i) the gradual thickening of the overflow with downstream distance, (ii) the advection of high salinity and temperature signals at the bottom along the channel with little dilution, and (iii) ambient water masses sandwiched between the overflow and surface mixed layer. To quantify mixing of the overflow with the ambient water masses, an entrainment parameter is determined from the transport increase along the slope and is expressed explicitly as a function of mean slope angle. Bulk Richardson numbers are estimated both from data and model and are related to the entrainment parameter. The range of entrainment parameter and its functional dependence on bulk Richardson number in this study are found to be in reasonable agreement with those reported from various laboratory experiments and that based on measurements of the Mediterranean overflow. The results reveal a complex dynamical interaction between shear-induced mixing and internal waves and illustrate the high computational and modeling requirements for numerical simulation of overflows to capture (at least in part) turbulent transports explicitly.
Direct Numerical Simulation of Differential Scalar Diffusion in Three-Dimensional Stratified Turbulence
Authors: Gargett Ann E. , Merryfield William J. , Holloway Greg
Published: February 2011

The potential for differential turbulent transport of oceanic temperature (T) and salinity (𝒮) is explored using three-dimensional direct numerical simulations of decaying stratified turbulence. The simulations employ a realistic molecular diffusion coefficient for T, and one for a “salt” scalar S that is 10 times smaller. Initially, a uniformly stratified medium is disturbed by a turbulent burst whose initial energy is assigned a range of values. In each instance, transports of T integrated over the subsequent decay of the burst exceed those of S. The more energetic cases occupy parameter ranges similar to, and exhibit spectral characteristics that are essentially indistinguishable from, those of direct observations of turbulence in the stratified ocean interior. In these cases, the turbulent diffusivity of T exceeds that of S by 6%–22%. These simulations underestimate the degree of differential diffusion between T and salinity 𝒮 (which has a molecular diffusivity 100 times less than T); thus at the Reynolds numbers attained by the simulations these results constitute lower bounds for differential diffusion associated with sporadic turbulence in the ocean. The simulation results are consistent with previous laboratory and two-dimensional numerical experiments and suggest that the assumption of equal turbulent diffusivities for T and 𝒮, commonly used in circulation modeling and in interpreting oceanic mixing measurements, should be reconsidered.
Laboratory Measurements of Differential Diffusion in a Diffusively Stable, Turbulent Flow
Authors: Jackson P. Ryan , Rehmann Chris R.
Published: February 2011

Laboratory experiments were performed to determine the conditions under which differential diffusion occurs and to evaluate its effect on the mixing efficiency. Diffusively stable profiles of temperature and salinity were stirred steadily by horizontally oscillating vertical rods. The two-component stratification ensures that both scalars experience the same stratification and forcing, or Richardson and Reynolds numbers. The eddy diffusivities KT and KS, for temperature and salinity, were estimated by fitting theoretical solutions of diffusion equations to measured profiles, and the mixing efficiency was computed as the ratio of the potential energy change during a stirring interval to the work done in that interval. Differential diffusion occurred for ɛa/νN2 < 300–500, where ɛa is an average dissipation rate computed from an integrated energy budget. The diffusivity ratio d = KS/KT varied between 0.5 and 1 in the range 50 < ɛa/νN2 < 500. The experiments also show that differential diffusion can significantly affect the mixing efficiency. An important dimensionless parameter is the density ratio Rρ, which is the ratio of the density change due to temperature to that due to salinity. Measurements in cases with low density ratio (Rρ ≈ 0.25) and high density ratio (Rρ ≈ 5) showed that the mixing efficiencies agreed well for weak stratification, or small Richardson number. For larger Richardson number, the efficiency for the high-density-ratio case exceeded that for the low-density-ratio case by as much as a factor of 1.5.
Observational Evidence for Flow between the Subtropical and Tropical Atlantic: The Atlantic Subtropical Cells*
Authors: Zhang Dongxiao , McPhaden Michael J. , Johns William E.
Published: February 2011

This study determines the mean pathways and volume transports in the pycnocline and surface layer for water flowing between the subtropical and tropical Atlantic Ocean, using potential vorticity, salinity, geostrophic flow maps on isopycnal surfaces, and surface drifter velocities. In both hemispheres, subducted salinity maximum waters flow into the Tropics in the pycnocline along both interior and western boundary pathways. The North Atlantic ventilating trajectories are confined to densities between about 23.2 and 26.0 σθ, and only about 2 Sv (Sv ≡ 106 m3 s–1) of water reaches the Tropics through the interior pathway, whereas the western boundary contributes about 3 Sv to the equatorward thermocline flow. Flow on shallower surfaces of this density range originates from the central Atlantic near 40°W between 12° and 16°N whereas flow on the deeper surfaces originates from near 20°W just off the coast of Africa at higher latitudes. The pathways skirt around the potential vorticity barrier located under the intertropical convergence zone and reach their westernmost location at about 10°N. In the South Atlantic, about 10 Sv of thermocline water reaches the equator through the combination of interior (4 Sv) and western boundary (6 Sv) routes in a slightly higher density range than in the North Atlantic. Similar to the North Atlantic, the shallower layers originate in the central part of the basin (along 10°–30°W at 10°–15°S) and the deeper layers originate at higher latitudes from the eastern part of the basin. However, the ventilation pathways are spread over a much wider interior window in the Southern Hemisphere than in the Northern Hemisphere that at 6°S extends from 10°W to the western boundary. The equatorward convergent flows in the thermocline upwell into the surface layer and return to the subtropics through surface poleward divergence. As much as 70% of the tropical Atlantic upwelling into the surface layer is associated with these subtropical circulation cells, with the remainder contributed by the warm return flow of the large-scale thermohaline overturning circulation.
A Model Study on the 1988–89 Warming Event in the Northern North Pacific
Authors: Luo Jing-Jia , Yamagata Toshio
Published: February 2011

Using outputs of a high-resolution ocean general circulation model, upper-ocean heat content budget and mixed layer heat budget are analyzed to investigate the reason for the 1988–89 decadal warming event in the northern North Pacific. The model reproduces realistic upper-ocean temperature changes in comparison with observational data. This analysis suggests that the horizontal mean geostrophic advection of anomalous temperature is the main contributor to the heat content increase around 1988–89, and surface heat flux forcing is the main contributor to increasing mixed layer temperature. The anomalous geostrophic advection of mean temperature plays a negative role in the increase of both the upper-ocean heat content and mixed layer temperature in midlatitudes around 1988–89. Another negative contribution to the mixed layer temperature increase is provided by the Ekman advection. In the Kuroshio Extension region, the warm upper-ocean heat content anomaly appears in 1987–88, in which the mean geostrophic advection also plays a dominant role. South of Japan the decadal warming appears even earlier, around 1985–86. The anomalous Kuroshio transport shows a decadal decreasing trend since the early 1980s and therefore cannot explain the late 1980s warming event in midlatitudes. The 1988–89 event is found to be closely linked with the decadal change of the Kuroshio path south of Japan. It is found that subtropical Rossby waves may influence the decadal temperature changes south of Japan.
Levels of Leadership
Authors: Epstein Joyce L. , Galindo Claudia L. , Sheldon Steven B.
Published: February 2011

Purpose: This study tests key constructs of sociocultural and organizational learning theories with quantitative methods to better understand the nature and impact of district and school leadership and actions on the quality of programs of family and community involvement. Research Design: Survey data from a “nested” sample of 24 districts and 407 schools are used to measure theoretical constructs of district assistance to schools and shared work on partnership program development. Hierarchical linear modeling (HLM) analyses explore the independent and simultaneous contributions of district leadership and school teamwork on the implementation of basic structures and advanced outreach in partnership programs. Also, gap analyses compare supplementary data from 220 schools that had consistent district leadership for 3 years to 106 schools without this support. Findings: HLM analyses show that principals’ support for family and community involvement and schools’ reports of district assistance contribute significantly to schools’ basic program implementation and to advanced outreach to involve all families in their children’s education. Over and above school measures, district leaders’ direct facilitation contributes to the quality of the school programs. Gap analyses indicate that schools with consistent district leadership take more basic and advanced actions to establish and improve their partnership programs. Conclusions: This study—with a large sample of districts and schools, appropriate quantitative methods, and a content focus on partnerships—provides strong empirical support for the importance of sociocultural and organizational theories in studying school improvement. Implications for improving district and school policy and practice are discussed.
Positive Psychology and Educational Administration
Authors: Hoy Wayne K. , Tarter C. John
Published: February 2011

The purpose of this essay is to develop a research agenda based on the relatively new perspective of positive psychology. The authors first offer a brief history of positive psychology including a working definition. Next, they make the distinction between humanistic and positive psychology, with emphasis on the research methods of positive psychologists. Then the authors examine the emerging impact of positive psychology on organizational studies and education. Finally, they turn to a few current examples of the utility of positive psychology and research to inform administration and guide practice.
Identification of Differential Item Functioning in Assessment Booklet Designs With Structurally Missing Data
Authors: Goodman Joshua T. , Willse John T. , Allen Nancy L. , Klaric John S.
Published: February 2011

The Mantel—Haenszel procedure is a popular technique for determining items that may exhibit differential item functioning (DIF). Numerous studies have focused on the strengths and weaknesses of this procedure, but few have focused the performance of the Mantel—Haenszel method when structurally missing data are present as a result of test booklet design. The current research compares the Type I error rate, power rate, and accuracy of DIF statistics when using the Mantel—Haenszel methods to detect DIF in three different test booklet designs that produce sparse data. Data were simulated for three different total sample sizes, fully crossed with three different test lengths, and two focal to reference group ratios. In general, the Mantel—Haenszel procedure was not adversely affected by sparseness of data under any of the booklet designs considered when sample size was adequately large. As sample sizes decrease, both the amount of sparseness and features of the booklet design may influence the ability to detect DIF.
California Psychological Inventory Dominance Scale Measurement Equivalence: General Population Normative and Indian, U.K., and U.S. Managerial Samples
Authors: Kulas John T. , Thompson Richard C. , Anderson Michael G.
Published: February 2011

The California Psychological Inventory’s Dominance scale was investigated for inconsistencies in item—trait associations across four samples (one American normative and three culturally dissociated manager groupings). The Kim, Cohen, and Park procedure was used, enabling simultaneous multigroup comparison in addition to the traditional differential item functioning focus on paired-group contrasts. Framing comparisons within Hofstede’s cultural dimensions, Dominance construct—item association inconsistencies were predicted to occur across Indian manager responses (when contrasted relatively with U.S. and U.K. responses). Results are consistent with the Hofstede predictions and have particular implications for empirically keyed assessments, multigroup contrasts, the cross-cultural expression of individual differences, and the generalizability of trait definitions across cultures.
Focus of Attention Affects Performance of Motor Skills in Music
Authors: Duke Robert A. , Cash Carla Davis , Allen Sarah E.
Published: February 2011

To test the extent to which learners performing a simple keyboard passage would be affected by directing their focus of attention to different aspects of their movements, 16 music majors performed a brief keyboard passage under each of four focus conditions arranged in a counterbalanced design—a total of 64 experimental sessions. As they performed the test passage, participants were directed to focus their attention on either their fingers, the piano keys, the piano hammers, or the sound produced. Complete MIDI data for all responses were digitally recorded by software written specifically for this experiment. Consistent with findings obtained in tests of other physical skills, the results show that performance was most accurate and generalizable when participants focused on the effects their movements produced rather than on the movements themselves, and that the more distal the focus of attention, the more accurate the motor control.
Effects of Listening Conditions, Error Types, and Ensemble Textures on Error Detection Skills
Authors: Waggoner Dori T.
Published: February 2011

This study was designed with three main purposes: (a) to investigate the effects of two listening conditions on error detection accuracy, (b) to compare error detection responses for rhythm errors and pitch errors, and (c) to examine the influences of texture on error detection accuracy. Undergraduate music education students ( N = 18) listened to purposefully incorrect performances of band literature in two formats, on recordings and while conducting a live ensemble. Pitch and rhythm errors were inserted into the music excerpts to investigate responses to different types of errors. Half of the excerpts were played by the full ensemble and half by a single section. Participants served as their own controls by completing the error detection tasks under all conditions. Results indicated that participants were significantly more successful in identifying errors in the recording condition than in the conducting condition. A significant interaction existed between the error type (pitch or rhythm) and the ensemble texture (single section or full ensemble). Participants identified rhythm errors more accurately in the single section texture and diagnosed pitch errors more successfully in the full ensemble excerpts.
Gender Differences of Popular Music Production in Secondary Schools
Authors: Abramo Joseph Michael
Published: February 2011

In this case study, the author inv estigated how students’ gender affected their participation in a secondary popular music class in which participants wrote and performed original music. Three same-gendered rock groups and two mixed-gendered rock groups were observ ed. Would students of different genders rehearse and compose differently? How would same-gendered processes compare to mixed-gendered processes? Research suggests that girls learn differently from boys and that gender—as distinct from sex—is formed in social env ironments. In research on popular music education, howev er, the participation of girls has been under-documented and under-theorized. This study found that boys and girls rehearsed and composed differently: Whereas the boys combined musical gestures and nonv erbal communication into a seamless sonic process, the girls separated talk and musical production. In the mixed-gendered groups, tensions arose because participants used different learning styles that members of the opposite gender misunderstood. Broadening popular music pedagogies to incorporate different practices is suggested.
Racial Identity and Risky Sexual Behaviors Among Black Heterosexual Men
Authors: Oparanozie Adannaa , Sales Jessica M. , DiClemente Ralph J. , Braxton Nikia D.
Published: February 2011

The purpose of this study was to examine the relationship between racial identity and risky sexual behaviors among young Black heterosexual men to better inform future HIV prevention interventions. A community sample of 80 self-identified African American heterosexual men aged 18 to 29 years completed an audio computer-assisted self-interview survey. Bivariate analyses were performed to assess the associations among variables related to demographics, racial identity, and sexual behaviors. Multivariate linear and logistic regression analyses were employed to determine the relationship between racial identity and risky sexual behaviors. Results indicate that more positive feelings toward African Americans and positive attitudes toward being Black predicted fewer sexual partners. The centrality of race was associated with a decrease in the odds of having concurrent sexual partners and marginally predicted increased condom use with a main female partner. Findings suggest that future HIV prevention interventions designed for African American heterosexual men should seek to strengthen their sense of racial identity.
Translating Team Creativity to Innovation Implementation
Authors: Somech Anit , Drach-Zahavy Anat
Published: February 2011

This study investigated team innovation as a process phenomenon by differentiating the creativity stage from the implementation stage. Based on the interactional approach, the authors argue that team composition (aggregated individual creative personality and functional heterogeneity) affects team creativity, which in turn promotes innovation implementation depending on the team’s climate for innovation. Results from a study of 96 primary care teams confirmed that aggregated individual creative personality, as well as functional heterogeneity, promotes team creativity, which in turn interacts with climate for innovation such that team creativity enhances innovation implementation only when climate for innovation is high.
Management Theory Applications of Prospect Theory: Accomplishments, Challenges, and Opportunities
Authors: Holmes R. Michael , Bromiley Philip , Devers Cynthia E. , Holcomb Tim R. , McGuire Jean B.
Published: February 2011

The authors review management research drawing on prospect theory, focusing primarily on studies in strategic management and organizational behavior/human resource management. These studies have made valuable contributions to several prominent research streams. However, they commonly underutilize or misconstrue central arguments from prospect theory. Furthermore, they illustrate that applying prospect theory in organizational settings poses several theoretical and methodological challenges. Thus, the authors review these studies, critically analyze them, and make suggestions to enrich future work.
Withholding Requests for Disability Accommodation
Authors: Baldridge David C. , Swift Michele L.
Published: February 2011

Prior research suggests that people with disabilities often do not request needed workplace accommodations, though relatively few studies address which factors influence the extent of such potentially self-limiting behavior. Drawing on workplace disability, help seeking, and social identity literature, this study proposes and tests a model of request withholding frequency using survey data from 279 people with hearing impairments. Consistent with expectations, older employees withheld requests less frequently; however, there was no main effect of gender. Moreover, the strength of the relationship between age and request withholding frequency was significantly weaker when the disability was more severe and when the age of disability onset was earlier. Similarly, disability severity influenced the strength of the relationship between gender and request withholding frequency, though the age of disability onset did not. These findings are consistent with social identity theory, in that those individual differences and disability attributes that shape social identities also appear to affect decisions to request disability accommodation. In practical terms, managers need to not only be supportive of disability accommodation requests but also recognize that some employees, such as young persons with disabilities, may need even more support, and support in a form that affirms or minimizes threats to other salient identities, such as their youth. Additional implications for management research and practice are discussed.
Explaining the Pathways Between Approach-Avoidance Personality Traits and Employees’ Job Search Behavior
Authors: Zimmerman Ryan D. , Boswell Wendy R. , Shipp Abbie J. , Dunford Benjamin B. , Boudreau John W.
Published: February 2011

Research suggests that certain personality characteristics lead to greater (or lesser) withdrawal from work, yet little research has examined exactly how personality translates into withdrawal behavior. To address this question, the present study demonstrated that the approach-avoidance personality traits of extraversion and neuroticism each showed simultaneous positive and negative effects on job search behaviors of employed individuals depending on the mediating mechanism involved (i.e., ambition values, job search self-efficacy, perceived job challenge, work burnout, perceived financial inadequacy, and job satisfaction). The authors’ findings extend theoretical insights on the pathways linking dispositional traits and employee withdrawal behaviors and suggest how employers can more precisely anticipate and mitigate employees’ search for new employment.
The Achilles’ Heel of the Brazilian Economy
Authors: de Casabianca Felix Blossier
Published: February 2011

Brazil’s important inflation problems were cured by the 1994 Real Plan, but this monetary reform also resulted in a very high SELIC rate, the central bank’s overnight lending rate. More than 15 years after this reform and in spite of excellent economic indicators, interest rates in Brazil are still abnormally high, thus restricting credit and undermining the country’s development. The purpose of the present article is to analyze the factors at the root of such high interest rates in order to see that a central bank reform appears to be the best solution to tackle these elevated interest rates.
Spontaneous Complex Polysaccharide Inclusions in the Skeletal Muscle of Purpose-bred Beagle Dogs
Authors: Wancket Lyn M. , Quist Erin M. , Le Net Jean-Loic , Guzman Roberto E. , Muravnick Kathleen B.
Published: February 2011

Amylase-resistant, periodic acid-Schiff (PAS)–positive inclusions were identified in the skeletal muscle of four of twenty-four purpose-bred beagle dogs from a routine toxicology study. Affected myofibers contained amorphous material filling up to 20% of the sarcoplasm that stained lightly basophilic with hematoxylin and eosin and was strongly PAS–positive with amylase resistance. Transmission electron micrographic examination of the inclusions revealed granular, non-membrane–bound, electron-dense material, consistent with polysaccharide. Although skeletal muscle inclusions with similar features have been reported in dogs in conjunction with systemic metabolic disorders and less often in muscle adjacent to nonmyogenic sarcomas, all four of these dogs lacked clinical or pathological findings diagnostic of a concurrent systemic metabolic or localized skeletal muscle disorder. Furthermore, these skeletal muscle inclusions were present in both vehicle- and test article–treated dogs and were considered an incidental finding that may occur spontaneously in clinically normal beagle dogs; as such, their presence in drug-treated animals should be interpreted with caution.
Investigating the Potential for Toxicity from Long-Term Use of the Herbal Products, Goldenseal and Milk Thistle
Authors: Dunnick June K. , Singh Bhanu , Nyska Abraham , Peckham John , Kissling Grace E. , Sanders J. Michael
Published: February 2011

Two-year toxicity studies were conducted on the widely used herbal products, goldenseal and milk thistle, in male and female F344/N rats and B6C3F1 mice. With goldenseal root powder, the primary finding was an increase in liver tumors in rats and mice, and with milk thistle extract, a decrease in spontaneous background tumors including mammary gland tumors in female rats and liver tumors in male mice. Increased tumorigenicity in rodents exposed to goldenseal root powder may be due in part to the topoisomerase inhibition properties of berberine, a major alkaloid constituent in goldenseal, or its metabolite, berberrubine. In the clinic, use of topoisomerase-inhibiting agents has been associated with secondary tumor formation and inhibition in DNA repair processes. In contrast, the radical-scavenging and antioxidant properties of silibinin and other flavonolignans in milk thistle extract may have contributed to the decrease in background tumors in rodents in the present studies. The fate of the active constituents of goldenseal and milk thistle is similar in humans and rodents; therefore, the modes of action may translate across species. Further studies are needed to extrapolate the findings to humans.
Spatial and sustained attention in relation to smoking status: behavioural performance and brain activation patterns
Authors: Vossel Simone , Warbrick Tracy , Mobascher Arian , Winterer Georg , Fink Gereon R
Published: February 2011

Nicotine enhances attentional functions. Since chronic nicotine exposure through smoking induces neuroadaptive changes in the brain at a structural and molecular level, the present functional MRI (fMRI) study aimed at investigating the neural mechanisms underlying visuospatial and sustained attention in smokers and non-smokers. Visuospatial attention was assessed with a location-cueing paradigm, while sustained attention was measured by changes in response speed over time. During invalid trials, neural activity within the basal forebrain was selectively enhanced in smokers and higher basal forebrain activity was associated with increased parietal cortex activation. Moreover, higher levels of expired carbon monoxide in smokers before scanning were associated with higher parietal cortex activation and faster responses to invalidly cued targets. Smokers showed a slowing of responses and additionally recruited an area within the right supramarginal gyrus with increasing time on task. Activity decreases over time were observed in visual areas in smokers. The data provide evidence for altered attentional functions in smokers as compared with non-smokers, which were partly modulated by residual nicotine levels and were observed at a behavioural level for sustained and at a neural level for spatial and sustained attention.
Onabotulinum toxin A treatment of cervicogenic headache: A randomised, double-blind, placebo-controlled crossover study
Authors: Linde Mattias , Hagen Knut , Salvesen Øyvind , Gravdahl Gøril Bruvik , Helde Grethe , Stovner Lars Jacob
Published: February 2011

Aims: Preliminary reports regarding injections in the neck of onabotulinum toxin A have been positive in cervicogenic headache (CeH). The aim was to perform the first methodologically rigorous trial.

Methods: A randomised, placebo-controlled, patient-, injector- and evaluator-blinded crossover study included 28 adult patients with a long-standing and treatment-resistant CeH. After a baseline period, injections of either onabotulinum toxin A or placebo were given in fixed sites in the neck muscles on the pain side. Second injections were given after ≥8 weeks. Patients were thereafter followed for another 8 weeks. A detailed headache calendar was filled in, and patients were followed with quality-of-life (QoL) questionnaires, algometry and neck mobility measurements.

Results: There was no significant difference between verum and placebo in a mixed linear model analysis ( p = 0.084) with regard to the primary end-point, reduction of days with moderate to severe headache. Six patients withdrew from the study before the second injections, but an intention-to-treat (ITT) analysis gave a similar result ( p = 0.27). There were no significant differences favouring verum in any of the secondary efficacy measures. Side-effects of onabotulinum toxin A were minor and short-lasting.

Conclusion: Onabotulinum toxin A in neck muscles does not seem to be beneficial in CeH.
The Influence of Arm and Shoulder Position on the Bear-Hug, Belly-Press, and Lift-Off Tests
Authors: Pennock Andrew T. , Pennington W. Wesley , Torry Michael R. , Decker Michael J. , Vaishnav Suketu B. , Provencher Matthew T. , Millett Peter J. , Hackett Thomas R.
Published: February 2011

Background: Clinical testing for the integrity of the subscapularis muscle includes the belly-press, lift-off, and bear-hug examinations. While these tests have been widely applied in clinical practice, there is considerable variation in arm positioning within each clinical examination.

Hypothesis: To determine the ideal arm and shoulder positions for isolating the subscapularis muscle while performing the bear-hug, belly-press, and lift-off tests.

Study Design: Controlled laboratory study.

Methods: The activity of 7 muscles was monitored in 20 healthy participants: upper and lower divisions of the subscapularis, supraspinatus, infraspinatus, latissimus dorsi, teres major, triceps, pectoralis major. Electromyogram data were collected and compared across each clinical test at varying arm positions: bear-hug (ideal position, 10° superior, 10° inferior to the shoulder line), belly-press (ideal position, maximum shoulder external rotation, and maximal shoulder internal rotation), and lift-off (ideal position, hand position 5 in. [12.7 cm] superior and 5 in. [12.7 cm] inferior to the midlumbar spine).

Results: Regardless of arm and shoulder position, the upper and lower subscapularis muscle activities were significantly greater than all other muscles while performing each test. No significant differences were observed between the upper and lower subscapularis divisions at any position within and across the 3 tests. There were no significant differences in subscapularis electromyogram activities across the 3 tests.

Conclusion: The level of subscapularis muscle activation was similar among the bear-hug, belly-press, and lift-off tests. The 3 tests activated the subscapularis significantly more than all other muscles tested but were not different from one another when compared across tests and positions. Although the bear-hug and lift-off tests have been described to activate differential portions of the subscapularis, the findings of this study do not support the preferential testing of a specific subscapular division across the 3 tests. As such, all 3 tests are effective in testing the integrity of the entire subscapularis muscle, although there does not appear to be an ideal position for selectively testing its divisions.

Clinical Relevance: Clinicians may feel comfortable in using any of the 3 tests, depending on the patient, to isolate the function of the subscapularis as a single muscle. Furthermore, clinicians should not solely focus on a patient’s arm position when administering an examination but also compare the affected arm to the contralateral shoulder when appropriate.
Thermomechanical and fracture properties of exfoliated nanoclay nanocomposites
Authors: Swaminathan Gowthaman , Shivakumar Kunigal
Published: February 2011

This article investigates the dispersion of nanoclay and its effect on the properties of nanoclay/epoxy nanocomposites developed using a high-shear mixing technique. Epon 828, Nanomer 1.30 E, and a compatible amine-curing agent (Epikure W) were the materials used. The dispersion of nanoclay was studied using XRD and TEM at different levels of magnification. Even though nanoclays were found to have exfoliated based on XRD’s d-spacing data (>8 nm), they remained as tactoids based on TEM data. The effect of curing on the dispersion of nanoclay was also studied using XRD analysis, which showed polymerization of resin in-between the nanoclay layers during curing. This polymerization was only helpful for the exfoliation of nanoclay, it could not completely delaminate and disperse the individual nanoclay layers. The nanocomposites were characterized using dynamic mechanical analysis and ASTM standard fracture tests. Measured elastic modulus was compared with the predicted modulus using modified Halpin—Tsai model. The experimental value was less than the predicted value and the difference was attributed to the poor dispersion of nanoclays. However, addition of 5.3 wt% nanoclay increased the storage modulus and the fracture toughness of epoxy resin by 21 % and 16%, respectively. The fracture morphologies indicated that the major toughening mechanism was due to crack deflection around nanoclay tactoids.
Numerical analysis of composite laminates stitched around a circular hole
Authors: Zhangxin Guo  , Xiaoping Han  , Xiping Zhu  , Xizhe Zhi
Published: February 2011

An approach is proposed to numerically study the composite laminates stitched around a circular hole. First, the local structure of stitching region is simplified and the finite element analysis is carried out. Then, the overall elastic constants of the equivalent yarns are obtained by comparing the numerical and experimental results. With this approach, the strain distributions are calculated, and the effects of stitching parameters such as edge distance, stitching needle span, row spacing, and the material and diameter of yarn are discussed on the strain concentration factors. It is indicated that the approach is valid for the existing experimental data, and can be applied to more cases of stitching enforcement.
Thermoplastic polyolefin nanocomposites: effect of mechanical, thermal, and morphological properties
Authors: Nalini R. , Nagarajan S. , Reddy B.S.R.
Published: February 2011

The polymer nanocomposites were prepared by melt compounding from polypropylene/thermoplastic elastomer (PP-TPE) with sodium montmorillonite (Na-MMT) and cloisite 20A using maleic anhydride modified PP-grafted maleic anhydride (PP-g-MA) as a compatibilizer. Three different weight percentages (3, 5, and 7 wt%) of nanoclay (Na-MMT or C20A) were used to study the effect on the properties of nanocomposites. The optimized clay composition of 5% was tested by varying the wt% of compatibilizer (5, 10, 15, and 20) to obtain better performance properties of nanocomposites. The excellent improvements in mechanical properties were observed by the incorporation 5 wt% cloisite20A with 5% compatibilizer. TPO nanocomposites show higher melting point and thermal degradation temperature on heat loading. The good thermal stability was confirmed from DSC and TGA. The intercalated/exfoliated phenomenon was indicated by the increase in Tg and storage modulus using DMA. Wide angle X-ray scattering (XRD) was employed to study the size and changes in the morphology; it is also provided conclusive evidence for the formation of exfoliated structures.
Size effects on the bending strength of fiber-reinforced polymer matrix composites
Authors: Nader Jacques W. , Dagher Habib J. , Lopez-Anido Roberto
Published: February 2011

This article investigates the size effects associated with length and width, on the bending strength of marine grade polymer matrix laminated composites. A new expression for predicting the strength size effect was developed and was verified using both laboratory testing and probabilistic finite element analysis (FEA). Woven [0/45/—45/0]5sf E-glass/vinyl ester material specimens with different lengths and widths and same thickness were evaluated to predict the effect of specimen size on the bending strength. In the probabilistic FEA models, elastic properties (E11, E22, G12, υ12), and strength parameters (F1t, F1c, F2t , F2c, F6, ε1t, ε 1c, ε2t, ε2c, ε12) of the woven fabric E-glass/vinyl ester ASTM D6272 coupons were considered as random fields, and generated using Monte Carlo simulations. The relationship between the bending strength and specimen size of the [0/45/—45/0]5sf lay-up was also evaluated experimentally. Thirty-two material specimens were prepared and tested according to ASTM D6272 using combinations of two span-to-thickness ratios (32 : 1 and 16 : 1), and two width-to-thickness ratios (3 : 1 and 1.5 : 1).
Geographic Access to Healthy and Unhealthy Foods for the Older Population in a U.S. Metropolitan Area
Authors: Yamashita Takashi , Kunkel Suzanne R.
Published: February 2011

Poor nutrition is known to be associated with a number of adverse health outcomes; adequate nutrition is related to a large number of factors, including geographic access to healthy foods. Access to healthy foods can be especially challenging for older people with any kind of transportation or mobility limitations. In addition, some older populations may have reduced access to healthy foods because of the unavailability of food outlets in their neighborhoods. Using the geographic information system (GIS), this study assessed census block level geographic accessibility to healthy and unhealthy food outlets in one county in Ohio. It was found that there was a noticeable disparity in geographic access to food outlets in this older population, depending on which part of the county they live in. These findings have implications for future public health research and policy planning.
What Community Resources Do Older Community-Dwelling Adults Use to Manage Their Osteoarthritis? A Formative Examination
Authors: Martin Kathryn R. , Schoster Britta , Woodard Janice , Callahan Leigh F.
Published: February 2011

Community resources can influence health outcomes, yet little research has examined how older individuals use community resources for osteoarthritis (OA) management. Six focus groups were conducted with 37 community-dwelling older adult African Americans and Whites who self-reported OA and resided in Johnston County, North Carolina. Descriptive analyses and qualitative constant comparison methodology revealed that individuals use local recreational facilities, senior centers, shopping centers, religious organizations, medical providers, pharmacies, and their social network for OA management. Participants also identified environmental characteristics (e.g., sidewalk conditions, curb-cuts, handicapped parking, automatic doors) that both facilitated and hindered use of community resources for OA management. Identified resources and environmental characteristics were organized around Corbin and Strauss framework tasks: medical/behavioral, role, and emotional management. As older Americans live with multiple chronic diseases, better understanding of what community resources are used for disease management may help to improve the health of community-dwelling adults, both with and without OA.
Current Concepts in Resuscitation
Authors: Pieracci Fredric M. , Biffl Walter L. , Moore Ernest E.
Published: February 2011

Early recognition and differentiation of shock, as well as goal-directed resuscitation, are fundamental principles in the care of the critically ill or injured patient. Substantial progress has been made over the last decade in the understanding of both shock and resuscitation. Specific areas of advancement, particularly pertaining to hemorrhagic shock, include a heightened appreciation of dynamic measurements of preload responsiveness (eg, respiratory-induced pulse pressure and venous diameter variability), an improved awareness of the detrimental effects of blood product transfusion, and better recognition of the complications of overzealous volume expansion. However, several areas of controversy remain regarding the optimal resuscitation strategy. These include the optimal targets for perfusion pressure and oxygen delivery, endpoints of resuscitation, resuscitative fluid, and transfusion strategies for packed red blood cells and blood products. This article reviews the diagnosis and differentiation of shock, measurements of tissue perfusion, current evidence regarding various resuscitative techniques, and complications of resuscitation.
Optimization of a wheel profile accounting for design robustness
Authors: Markine V L , Shevtsov I Y
Published: February 2011

The article describes a numerical procedure for optimum design of a railway wheel profile. The optimization performed using the optimality criteria based on a rolling radius difference function, which account for the reduction of wear and contact stresses as well as for stability of the vehicle. As a general optimization technique the multipoint approximations method is employed. The described procedure has been applied to improve the wheel profile design for a passenger train that was suffering from rolling contact fatigue defects in the rails and wheels. In order to account for uncertainties inherent to the wheel production process, the robustness of the optimum wheel profile was analysed. The failure criterion was formulated using the vehicle stability requirement. The failure probability was estimated using the Monte Carlo method and modified Latin hypercube sampling technique. The results are presented and discussed.
Communication Challenges for Solar System Exploration Missions
Authors: Bannister N P
Published: February 2011

Obtaining detailed information from solar system exploration missions requires the use of reliable, high-performance communications systems. Planetary landers and orbiters experience a wide variety of challenges, which complicate the design of communications architecture, and which affect the ability of the spacecraft to transmit significant quantities of data back to Earth. Aside from the large distances involved, the spacecraft environment dominates the design and capability of the communications system. As missions become more ambitious in the quantity of data to be generated and the types of environment to be explored, new technologies and techniques are required to meet these communication needs. This article reviews some of the major challenges facing the next generation of solar system missions, and outlines some of the solutions which have been proposed to address them.
Simulation of the dynamic processes in a scroll expander—generator used for small-scale organic Rankine cycle system
Authors: Guangbin L , Yuanyang Z , Yunxia L , Liansheng L
Published: February 2011

The scroll expander—generator is suitable to be used in the small-scale organic Rankine cycle system to generate electricity. In this article, a mathematical model has been developed which includes thermodynamic model, mechanical model, and load resistance model. The stable rotating speed, volumetric efficiency, and isentropic efficiency influenced by the suction pressure, discharge pressure, and generated current have been analysed. The results show that the stable condition of scroll expander—generator is determined by the driven and resistance moments. The transient rotating speed increases with the running time until the machine runs stably in the starting process. The scroll expander—generator is accelerated or decelerated when the suction pressure, discharge pressure, and generated current are changed. The stable time increases with the variation of suction pressure either in the acceleration or deceleration process. The stable rotating speed and volumetric efficiency increase with the suction pressure but decrease with the discharge pressure and generated current. The isentropic efficiency increases with the suction pressure but decreases with the generated current. A maximum isentropic efficiency is found with the increase of discharge pressure.