Engineered passive bioreactive barriers: risk-managing the legacy of industrial soil and groundwater pollution.

PubMed

Kalin, Robert M

2004-06-01

Permeable reactive barriers are a technology that is one decade old, with most full-scale applications based on abiotic mechanisms. Though there is extensive literature on engineered bioreactors, natural biodegradation potential, and in situ remediation, it is only recently that engineered passive bioreactive barrier technology is being considered at the commercial scale to manage contaminated soil and groundwater risks. Recent full-scale studies are providing the scientific confidence in our understanding of coupled microbial (and genetic), hydrogeologic, and geochemical processes in this approach and have highlighted the need to further integrate engineering and science tools.

Development and psychometric evaluation of the Dialysis patient-perceived Exercise Benefits and Barriers Scale.

PubMed

Zheng, Jing; You, Li-Ming; Lou, Tan-Qi; Chen, Nian-Chang; Lai, De-Yuan; Liang, Yan-Yi; Li, Ying-Na; Gu, Ying-Ming; Lv, Shao-Fen; Zhai, Cui-Qiu

2010-02-01

Perceptions of exercise benefits and barriers affect exercise behavior. Because of the clinical course and treatment, dialysis patients differ from the general population in their perceptions of exercise benefits and barriers, especially the latter. At present, no valid instruments for assessing perceived exercise benefits and barriers in dialysis patients are available. Our goal was to develop and test the psychometric properties of the Dialysis patient-perceived Exercise Benefits and Barriers Scale (DPEBBS). A literature review and two focus groups were conducted to generate the initial item pool. An expert panel examined the content validity. Then, 269 Chinese hemodialysis patients were recruited by convenience sampling. Exploratory and confirmatory factor analyses were used to test construct validity. Finally, internal consistency and test-retest reliability were assessed. The expert panel determined that the content validity index was satisfactory. The final 24-item scale consisted of six factors explaining 57% of the total variance in the data. Confirmative factor analysis supported the six-factor structure and a higher-order model. Cronbach's alpha was 0.87 for the total scale, and 0.84 for test-retest reliability. The DPEBBS was a valid and reliable instrument for evaluating dialysis patients' perceived benefits and barriers to exercise. The application value of this scale remains to be investigated by increasing the sample size and evaluating patients undergoing different dialysis modalities and coming from different regions and cultural backgrounds. Copyright 2009 Elsevier Ltd. All rights reserved.

What are validated self-report adherence scales really measuring?: a systematic review

PubMed Central

Nguyen, Thi-My-Uyen; Caze, Adam La; Cottrell, Neil

2014-01-01

Aims Medication non-adherence is a significant health problem. There are numerous methods for measuring adherence, but no single method performs well on all criteria. The purpose of this systematic review is to (i) identify self-report medication adherence scales that have been correlated with comparison measures of medication-taking behaviour, (ii) assess how these scales measure adherence and (iii) explore how these adherence scales have been validated. Methods Cinahl and PubMed databases were used to search articles written in English on the development or validation of medication adherence scales dating to August 2012. The search terms used were medication adherence, medication non-adherence, medication compliance and names of each scale. Data such as barriers identified and validation comparison measures were extracted and compared. Results Sixty articles were included in the review, which consisted of 43 adherence scales. Adherence scales include items that either elicit information regarding the patient's medication-taking behaviour and/or attempts to identify barriers to good medication-taking behaviour or beliefs associated with adherence. The validation strategies employed depended on whether the focus of the scale was to measure medication-taking behaviour or identify barriers or beliefs. Conclusions Supporting patients to be adherent requires information on their medication-taking behaviour, barriers to adherence and beliefs about medicines. Adherence scales have the potential to explore these aspects of adherence, but currently there has been a greater focus on measuring medication-taking behaviour. Selecting the ‘right’ adherence scale(s) requires consideration of what needs to be measured and how (and in whom) the scale has been validated. PMID:23803249

Psychometric properties of the Exercise Benefits/Barriers Scale in Mexican elderly women

PubMed Central

Enríquez-Reyna, María Cristina; Cruz-Castruita, Rosa María; Ceballos-Gurrola, Oswaldo; García-Cadena, Cirilo Humberto; Hernández-Cortés, Perla Lizeth; Guevara-Valtier, Milton Carlos

2017-01-01

ABSTRACT Objective: analyze and assess the psychometric properties of the subscales in the Spanish version of the Exercise Benefits/Barriers Scale in an elderly population in the Northeast of Mexico. Method: methodological study. The sample consisted of 329 elderly associated with one of the five public centers for senior citizens in the metropolitan area of Northeast Mexico. The psychometric properties included the assessment of the Cronbach's alpha coefficient, the Kaiser Meyer Olkin coefficient, the inter-item correlation, exploratory and confirmatory factor analysis. Results: in the principal components analysis, two components were identified based on the 43 items in the scale. The item-total correlation coefficient of the exercise benefits subscale was good. Nevertheless, the coefficient for the exercise barriers subscale revealed inconsistencies. The reliability and validity were acceptable. The confirmatory factor analysis revealed that the elimination of items improved the goodness of fit of the baseline scale, without affecting its validity or reliability. Conclusion: the Exercise Benefits/Barriers subscale presented satisfactory psychometric properties for the Mexican context. A 15-item short version is presented with factorial structure, validity and reliability similar to the complete scale. PMID:28591306

The Perinatal Palliative Care Perceptions and Barriers Scale Instrument©: development and validation.

PubMed

Wool, Charlotte; Northam, Sally

2011-12-01

To devise and test an instrument measuring clinician perceptions of perinatal palliative care (PPC) and barriers to care delivery. PPC was theorized to involve the care of pregnant women and their families after prenatal testing resulted in a life-limiting fetal diagnosis. Both giving birth to a child with a life-limiting condition or termination of pregnancy for fetal anomaly can be emotionally traumatic life events. Clinicians were thought to face ethical dilemmas that involved approaches to care for this population. The ethical dilemmas were measured on a perceptions scale using items about informed consent, justice, beneficence, and autonomy. Barriers were theorized as obstacles to delivering quality PPC and included insufficient education, personal discomfort, and difficulty garnering team or administrative support for care. Licensed clinicians practicing in the perinatal field. Stage 1 entailed instrument development and validation, which was achieved through a Delphi study involving 11 expert panelists. The devised instrument included 64 six-point Likert items. In stage 2, a computer survey gathered data from a multidisciplinary, clinician group. A total of 264 clinicians completed the survey. Exploratory factor analysis with varimax rotation was used to validate the instrument, evaluate the factors, and summarize the explained variance achieved by sum scores of the perceptions and barriers scales. The perceptions scale was reduced to 23 items with a 6-factor solution explaining 67% of the variance with a good internal consistency reliability of 0.77 (Cronbach α). The 22-item barriers scale had a 6-factor solution explaining 71% of the variance with an alpha reliability of 0.83. The Perinatal Palliative Care Perceptions and Practice Barriers Scale instrument is a valid and reliable measure of PPC perceptions and barriers for measuring the attitudes of physicians and nurses. Use of this instrument can foster educational programs and hospital planning for PPC teams that provide grieving families with the varied support they need. It is also a useful instrument for examining trends in the clinician perspectives and practice barriers as more genetic testing and subsequent terminal diagnoses occur.

A Numerical Comparison of Barrier and Modified Barrier Methods for Large-Scale Bound-Constrained Optimization

NASA Technical Reports Server (NTRS)

Nash, Stephen G.; Polyak, R.; Sofer, Ariela

1994-01-01

When a classical barrier method is applied to the solution of a nonlinear programming problem with inequality constraints, the Hessian matrix of the barrier function becomes increasingly ill-conditioned as the solution is approached. As a result, it may be desirable to consider alternative numerical algorithms. We compare the performance of two methods motivated by barrier functions. The first is a stabilized form of the classical barrier method, where a numerically stable approximation to the Newton direction is used when the barrier parameter is small. The second is a modified barrier method where a barrier function is applied to a shifted form of the problem, and the resulting barrier terms are scaled by estimates of the optimal Lagrange multipliers. The condition number of the Hessian matrix of the resulting modified barrier function remains bounded as the solution to the constrained optimization problem is approached. Both of these techniques can be used in the context of a truncated-Newton method, and hence can be applied to large problems, as well as on parallel computers. In this paper, both techniques are applied to problems with bound constraints and we compare their practical behavior.

Small scale monitoring of a bioremediation barrier using miniature electrical resistivity tomography

NASA Astrophysics Data System (ADS)

Sentenac, Philippe; Hogson, Tom; Keenan, Helen; Kulessa, Bernd

2015-04-01

The aim of this study was to assess, in the laboratory, the efficiency of a barrier of oxygen release compound (ORC) to block and divert a diesel plume migration in a scaled aquifer model using miniature electrical resistivity tomography (ERT) as the monitoring system. Two plumes of contaminant (diesel) were injected in a soil model made of local sand and clay. The diesel plumes migration was imaged and monitored using a miniature resistivity array system that has proved to be accurate in soil resistivity variations in small-scaled models of soil. ERT results reflected the lateral spreading and diversion of the diesel plumes in the unsaturated zone. One of the contaminant plumes was partially blocked by the ORC barrier and a diversion and reorganisation of the diesel in the soil matrix was observed. The technique of time-lapse ERT imaging showed that a dense non-aqueous phase liquid (DNAPL) contaminant like diesel can be monitored through a bioremediation barrier and the technique is well suited to monitor the efficiency of the barrier. Therefore, miniature ERT as a small-scale modelling tool could complement conventional techniques, which require more expensive and intrusive site investigation prior to remediation.

The perceived benefits and barriers to exercise participation in persons with multiple sclerosis.

PubMed

Stroud, Nicole; Minahan, Clare; Sabapathy, Surendran

2009-01-01

The purpose of this study was to examine the perceived benefits and barriers to exercise participation in persons with multiple sclerosis (MS). A cross-sectional postal survey comprised of 93 adults with MS was conducted. Participants completed the Exercise Benefits and Barriers Scale (EBBS), Spinal Cord Injury Exercise Self-Efficacy Scale (EXSE), Multiple Sclerosis Impact Scale, Disease Steps Scale and International Physical Activity Questionnaire. Forty-three percent of the participants were classified as exercising individuals (EX group) as compared with non-exercising individuals (non-EX group). Participants in the EX group reported significantly higher scores on the EBBS and EXSE. Items related to physical performance and personal accomplishment were cited as the greatest perceived benefits to exercise participation and those items related to physical exertion as the greatest perceived barriers to both the EX and non-EX groups. When compared with previous studies conducted in the general population, the participants in the present study reported different perceived barriers to exercise participation. Furthermore, awareness of the benefits of physical activity is not sufficient to promote exercise participation in persons with MS. Perceived exercise self-efficacy is shown to play an important role in promoting exercise participation in persons with MS.

Time scales of tunneling decay of a localized state

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ban, Yue; Muga, J. G.; Sherman, E. Ya.

2010-12-15

Motivated by recent time-domain experiments on ultrafast atom ionization, we analyze the transients and time scales that characterize, aside from the relatively long lifetime, the decay of a localized state by tunneling. While the tunneling starts immediately, some time is required for the outgoing flux to develop. This short-term behavior depends strongly on the initial state. For the initial state, tightly localized so that the initial transients are dominated by over-the-barrier motion, the time scale for flux propagation through the barrier is close to the Buettiker-Landauer traversal time. Then a quasistationary, slow-decay process follows, which sets ideal conditions for observingmore » diffraction in time at longer times and distances. To define operationally a tunneling time at the barrier edge, we extrapolate backward the propagation of the wave packet that escaped from the potential. This extrapolated time is considerably longer than the time scale of the flux and density buildup at the barrier edge.« less

Calibration and validation of the Physical Activity Barrier Scale for persons who are blind or visually impaired.

PubMed

Lee, Miyoung; Zhu, Weimo; Ackley-Holbrook, Elizabeth; Brower, Diana G; McMurray, Bryan

2014-07-01

It is critical to employ accurate measures when assessing physical activity (PA) barriers in any subpopulation, yet existing measures are not appropriate for persons with blindness or visual impairment (PBVI) due to a lack of validity or reliability evidence. To develop and calibrate a PA barrier scale for PBVI. An expert panel (n = 3) and 18 PBVI were recruited to establish content validity for a PA barriers subscale; 160 PBVI (96 females) completed the scale along with the Physical Activity Scale for Individuals with Physical Disabilities for calibration. To establish construct-related validity evidence, Confirmative factor analysis (CFA) and Rasch analysis were applied. To investigate internal consistency and reliability, Cronbach's alpha and the reliability coefficient (R) were employed, respectively. Following CFA and Rasch analyses, five items were eliminated due to misfits; reliability coefficients were unchanged upon deletion of these items. The barriers perceived by PBVI to have the most negative impact on PA included "lack of self-discipline" (logit = 1.40) and "lack of motivation" (logit = 1.27). "Too many stairs in the exercise facility" (logit = -1.49) was perceived to have the least impact. The newly-developed scale was found to be a valid and reliable tool for evaluating PA barriers in PBVI. To enhance promotion of health-producing levels of PA in PBVI, practitioners should consider applying this new tool as a precursor to programs aimed at improving PA participation in this group. Copyright © 2014 Elsevier Inc. All rights reserved.

Measurement of turbulence decorrelation during transport barrier evolution in a high-temperature fusion plasma.

PubMed

Nazikian, R; Shinohara, K; Kramer, G J; Valeo, E; Hill, K; Hahm, T S; Rewoldt, G; Ide, S; Koide, Y; Oyama, Y; Shirai, H; Tang, W

2005-04-08

A low power polychromatic beam of microwaves is used to diagnose the behavior of turbulent fluctuations in the core of the JT-60U tokamak during the evolution of the internal transport barrier. A continuous reduction in the size of turbulent structures is observed concomitant with the reduction of the density scale length during the evolution of the internal transport barrier. The density correlation length decreases to the order of the ion gyroradius, in contrast with the much longer scale lengths observed earlier in the discharge, while the density fluctuation level remain similar to the level before transport barrier formation.

Scale Development: Perceived Barriers to Public Use of School Recreational Facilities

ERIC Educational Resources Information Center

Spengler, John O.; Ko, Yong Jae; Connaughton, Daniel P.

2012-01-01

Objectives: To test an original scale assessing perceived barriers among school administrators to allowing community use of school recreational facilities outside of regular school hours. Methods: Exploratory factor analysis (EFA) and confirmatory factor analysis (CFA). Results: Using EFA and CFA, we found that a model including factors of…

Barriers to activity and participation for stroke survivors in rural China.

PubMed

Zhang, Lifang; Yan, Tiebin; You, Liming; Li, Kun

2015-07-01

To investigate environmental barriers reported by stroke survivors in the rural areas of China and to determine the impact of environmental barriers on activity and participation relative to demographic characteristics and body functioning. Cross-sectional survey. Structured interviews in the participants' homes. Community-dwelling stroke survivors in the rural areas of China (N=639). Not applicable. Activity and participation (Chinese version of the World Health Organization Disability Assessment Schedule 2.0), environmental barriers (Craig Hospital Inventory of Environmental Factors), neurological function (Canadian Neurological Scale), cognitive function (Abbreviated Mental Test), and depression (6-item Hamilton Rating Scale for Depression). Physical/structural barriers are the major impediment to activity and participation for these participants (odds ratio, 1.86 and 1.99 for activity and participation, respectively; P<.01). Services/assistance barriers primarily impede participation rather than activity (odds ratio, 1.58 in participation; P<.05). Physical/structural and services/assistance barriers were considered the dominant barriers to activity and participation for stroke survivors in the rural areas of China. Attitudinal/support and policy barriers did not emerge as serious concerns. To generate an enabling environment, physical/structural and services/assistance barriers are the environmental barriers to be decreased and eliminated first. Copyright © 2015 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

A design study for a medium-scale field demonstration of the viscous barrier technology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moridis, G.; Yen, P.; Persoff, P.

1996-09-01

This report is the design study for a medium-scale field demonstration of Lawrence Berkeley National Laboratory`s new subsurface containment technology for waste isolation using a new generation of barrier liquids. The test site is located in central California in a quarry owned by the Los Banos Gravel Company in Los Banos, California, in heterogeneous unsaturated deposits of sand, silt, and -ravel typical of many of the and DOE cleanup sites and particularly analogous to the Hanford site. The coals of the field demonstration are (a) to demonstrate the ability to create a continuous subsurface barrier isolating a medium-scale volume (30more » ft long by 30 ft wide by 20 ft deep, i.e. 1/10th to 1/8th the size of a buried tank at the Hanford Reservation) in the subsurface, and (b) to demonstrate the continuity, performance, and integrity of the barrier.« less

Nivel de Actividad Física, Autoeficacia, Beneficios y Barreras Percibidas en Mujeres Mayores Mexicanas Independientes (Physical Activity Level, Exercise Self-Efficacy, Benefits and Perceived Barriers of Independent Mexican Older Women).

PubMed

Enríquez-Reyna, María Cristina; Cruz-Castruita, Rosa María; Zamarripa, Jorge; Ceballos-Gurrola, Oswaldo; Guevara-Valtier, Milton Carlos

2016-03-01

This descriptive comparative study examined differences in personal characteristics, exercise self-efficacy, benefits and barriers of independent elderly women to perform physical activity (PA) according with the PA level. Two hundred three women older than 60 years of age, from a community located in Nuevo Leon, Mexico participated in the study. Data was collected using: a) A personal data questionnaire, b) Exercise Self-Efficacy Scale, c) Exercise Benefits/ Barriers Scale and d) Physical Activity Scale for the Elderly were completed. Age was similar in participants with low and acceptable PA level. Participants with lower levels of PA reported consuming more medications, fewer years of education and lower values of exercise self-efficacy, benefits and barriers. In this sample, exercise self-efficacy and benefits were positively associated with the PA level. © 2016. All rights reserved.

Barriers and Perceived Stress Levels of Internationals Living in the United States

ERIC Educational Resources Information Center

Davis, Terah L.

2017-01-01

This study explored the perceived stress level of international students who faced barriers to employment upon graduation from an American post-secondary institution. The Barriers to Employment Success Inventory (BESI) was used to assess employment barriers and the Perceived Stress Scale (PSS) assessed the perceived level of stress experienced by…

Creation and validation of the barriers to alcohol reduction (BAR) scale using classical test theory and item response theory.

PubMed

Kunicki, Zachary J; Schick, Melissa R; Spillane, Nichea S; Harlow, Lisa L

2018-06-01

Those who binge drink are at increased risk for alcohol-related consequences when compared to non-binge drinkers. Research shows individuals may face barriers to reducing their drinking behavior, but few measures exist to assess these barriers. This study created and validated the Barriers to Alcohol Reduction (BAR) scale. Participants were college students ( n  = 230) who endorsed at least one instance of past-month binge drinking (4+ drinks for women or 5+ drinks for men). Using classical test theory, exploratory structural equation modeling found a two-factor structure of personal/psychosocial barriers and perceived program barriers. The sub-factors, and full scale had reasonable internal consistency (i.e., coefficient omega = 0.78 (personal/psychosocial), 0.82 (program barriers), and 0.83 (full measure)). The BAR also showed evidence for convergent validity with the Brief Young Adult Alcohol Consequences Questionnaire ( r  = 0.39, p  < .001) and discriminant validity with Barriers to Physical Activity ( r  = -0.02, p  = .81). Item Response Theory (IRT) analysis showed the two factors separately met the unidimensionality assumption, and provided further evidence for severity of the items on the two factors. Results suggest that the BAR measure appears reliable and valid for use in an undergraduate student population of binge drinkers. Future studies may want to re-examine this measure in a more diverse sample.

Analysis and experimental study on formation conditions of large-scale barrier-free diffuse atmospheric pressure air plasmas in repetitive pulse mode

NASA Astrophysics Data System (ADS)

Li, Lee; Liu, Lun; Liu, Yun-Long; Bin, Yu; Ge, Ya-Feng; Lin, Fo-Chang

2014-01-01

Atmospheric air diffuse plasmas have enormous application potential in various fields of science and technology. Without dielectric barrier, generating large-scale air diffuse plasmas is always a challenging issue. This paper discusses and analyses the formation mechanism of cold homogenous plasma. It is proposed that generating stable diffuse atmospheric plasmas in open air should meet the three conditions: high transient power with low average power, excitation in low average E-field with locally high E-field region, and multiple overlapping electron avalanches. Accordingly, an experimental configuration of generating large-scale barrier-free diffuse air plasmas is designed. Based on runaway electron theory, a low duty-ratio, high voltage repetitive nanosecond pulse generator is chosen as a discharge excitation source. Using the wire-electrodes with small curvature radius, the gaps with highly non-uniform E-field are structured. Experimental results show that the volume-scaleable, barrier-free, homogeneous air non-thermal plasmas have been obtained between the gap spacing with the copper-wire electrodes. The area of air cold plasmas has been up to hundreds of square centimeters. The proposed formation conditions of large-scale barrier-free diffuse air plasmas are proved to be reasonable and feasible.

An automated approach for extracting Barrier Island morphology from digital elevation models

NASA Astrophysics Data System (ADS)

Wernette, Phillipe; Houser, Chris; Bishop, Michael P.

2016-06-01

The response and recovery of a barrier island to extreme storms depends on the elevation of the dune base and crest, both of which can vary considerably alongshore and through time. Quantifying the response to and recovery from storms requires that we can first identify and differentiate the dune(s) from the beach and back-barrier, which in turn depends on accurate identification and delineation of the dune toe, crest and heel. The purpose of this paper is to introduce a multi-scale automated approach for extracting beach, dune (dune toe, dune crest and dune heel), and barrier island morphology. The automated approach introduced here extracts the shoreline and back-barrier shoreline based on elevation thresholds, and extracts the dune toe, dune crest and dune heel based on the average relative relief (RR) across multiple spatial scales of analysis. The multi-scale automated RR approach to extracting dune toe, dune crest, and dune heel based upon relative relief is more objective than traditional approaches because every pixel is analyzed across multiple computational scales and the identification of features is based on the calculated RR values. The RR approach out-performed contemporary approaches and represents a fast objective means to define important beach and dune features for predicting barrier island response to storms. The RR method also does not require that the dune toe, crest, or heel are spatially continuous, which is important because dune morphology is likely naturally variable alongshore.

Insertion loss of noise barriers on an aboveground, full-scale model longwall coal mining shearer.

PubMed

Sweeney, Daniel D; Slagley, Jeremy M; Smith, David A

2010-05-01

The U.S. mining industry struggles with hazardous noise and dust exposures in underground mining. Specifically, longwall coal mine shearer operators are routinely exposed to noise levels at 151% of the allowable daily dose, and approximately 20% exceed regulatory dust levels. In the current study, a partial barrier was mounted on the full-scale mock shearer at the National Institute for Occupational Safety and Health Pittsburgh Research Laboratory. A simulated, full-scale, coal mine longwall shearer operation was employed to test the feasibility of utilizing a barrier to separate the shearer operator from the direct path of the noise and dust source during mining operations. In this model, noise levels at the operators' positions were reduced by 2.6 to 8.2 A-weighted decibels (dBA) from the application of the test barriers. Estimated insertion loss underground was 1.7 to 7.3 dBA. The barrier should be tested in an underground mining operation to determine if it can reduce shearer operators' noise exposure to below regulatory limits.

Development and Exploration of the Experiences with Classism Scale

ERIC Educational Resources Information Center

Thompson, Mindi N.; Subich, Linda M.

2013-01-01

The examination of barriers in relation to college students' vocational choice and development is an important area of research, but the barrier of classism is relatively underexamined. This may be due to the deficiencies in measurement, so we describe herein the development of a new measure, the Experiences with Classism scale (EWCS). The EWCS…

Measuring Perceived Benefits and Perceived Barriers for Physical Activity

ERIC Educational Resources Information Center

Brown, Seth A.

2005-01-01

Objectives: To evaluate the psychometric properties and relationship to physical activity levels of the Exercise Benefits/Barriers Scale (EBBS) among college students. Methods: A total of 398 college students completed the EBBS and a measure of self-efficacy, the Physical Exercise Self-Efficacy Scale. In addition, a subsample of 275 students also…

MASH TL-4 crash testing and evaluation of the RESTORE barrier.

DOT National Transportation Integrated Search

2015-11-01

Three full-scale vehicle crash tests were conducted according to the MASH Test Level 4 (TL-4) safety performance criteria on a : restorable and reusable energy-absorbing roadside/median barrier, designated the RESTORE barrier. The system utilized for...

Evaluation of the New York low-tension three-cable barrier on curved alignment.

DOT National Transportation Integrated Search

2013-02-01

Three full-scale crash tests were performed on the New York Department of Transportations (NYSDOTs) curved, lowtension, : three-cable barrier systems utilizing the MASH Test Level 3 safety performance criteria. The cable barrier system : for te...

Physical inactivity is associated with low self efficacy and social support among patients with hypertension in Nigeria.

PubMed

Idowu, O A; Adeniyi, A F; Atijosan, O J; Ogwumike, O O

2013-06-01

BACKGROUND Physical inactivity is a major factor in the development of many chronic illnesses, including hypertension. Evidence highlighting links among physical activity participation and psychosocial constructs such as self efficacy, social support and perceived barriers among hypertensive patients in the Nigerian population is scarce. This study explored the associations between physical activity and each of self efficacy, social support and perceived barriers. METHODS Two hundred and twelve patients receiving treatment in two tertiary health institutions located in Ekiti State, Nigeria were surveyed cross-sectionally. Physical activity level, self efficacy, social support and perceived barriers were measured with the International Physical Activity Questionnaire, Exercise Self-Efficacy Scale, Medical Outcomes Social Support Scale and Exercise Benefits and Barrier Scale respectively. RESULTS Level of physical activity was significantly associated with self efficacy (r(s) = 0.67, p < 0.01, = 0.45) and social support (r(s) = 0.80, p < 0.01, = 0.64), with most participants (56.1%) being physically inactive. However, no association was found between physical activity level and perceived barriers (r(s) = 0.07, p > 0.01, = 0.005). CONCLUSION Most of the hypertensive patients presented with low levels of physical activity. Physical activity was associated with psychosocial constructs including self efficacy and social support but not with perceived barriers.

Barriers to and Facilitators of Research Utilization: A Survey of Registered Nurses in China

PubMed Central

Wang, Li-Ping; Jiang, Xiao-Lian; Wang, Lei; Wang, Guo-Rong; Bai, Yang-Jing

2013-01-01

Aims This survey aims to describe the perception of barriers to and facilitators of research utilization by registered nurses in Sichuan province, China, and to explore the factors influencing the perceptions of the barriers to and facilitators of research utilization. Methods A cross sectional survey design and a double cluster sampling method were adopted. A total of 590 registered nurses from 3 tertiary level hospitals in Sichuan province, China, were recruited in a period from September 2006 to January 2007. A modified BARRUERS Scale and a Facilitators Scale were used. Data were analyzed with descriptive statistics, rank transformation test, and multiple linear regression. Results Barriers related to the setting subscale were more influential than barriers related to other subscales. The lack of authority was ranked as the top greatest barrier (15.7%), followed by the lack of time (13.4%) and language barrier (15.0%). Additional barriers identified were the reluctance of patients to research utilization, the lack of funding, and the lack of legal protection. The top three greatest facilitators were enhancing managerial support (36.9%), advancing education to increase knowledge base (21.1%), and increasing time for reviewing and implementing (17.5%), while cooperation of patients to research utilization, establishing a panel to evaluate researches, and funding were listed as additional facilitators. Hospital, educational background, research experience, and knowledge on evidence-based nursing were the factors influencing perceptions of the barriers and facilitators. Conclusions Nurses in China are facing a number of significant barriers in research utilization. Enhancing managerial support might be the most promising facilitator, given Chinese traditional culture and existing health care system. Hospital, educational background, research experience and knowledge on evidence-based nursing should be taken into account to promote research utilization. The BARRIERS Scale should consider funding and involvement of patients in research utilization. PMID:24312380

A reduced-scale railway noise barrier's insertion loss and absorption coefficients: comparison of field measurements and predictions

NASA Astrophysics Data System (ADS)

Busch, T. A.; Nugent, R. E.

2003-10-01

In situ testing determined the insertion loss ( IL) and absorption coefficients of a candidate absorptive noise barrier (soundwall) to abate railway noise for residents of Anaheim, CA. A 4000 m barrier is proposed south of the tracks, but residential areas to the north have expressed concerns that barrier reflections will increase their noise exposure. To address these concerns, a 3.66 m high by 14.6 m long demonstration barrier was built in the parking lot of Edison Field, Anaheim, as part of a public open house, thereby allowing for acoustical measurements. Insertion loss ( IL) was measured in third-octave bands assuming 1/2-scale construction. The IL for three, scaled railway noise sub-sources (rail/wheel interface, locomotive, and train horn) was measured at six, scaled distances. The highest total, A-weighted IL, after corrections for finite-barrier and point-source speaker effects was 22 dB(A) for rail/wheel noise, 18 dB(A) for locomotive noise, and 20 dB(A) for train horn noise. These results can be compared favourably to IL predictions made using algorithms from the US Federal Rail Administration (FRA) noise assessment guidelines. For the actual barrier installation, shielded residential receivers located south of the project are expected to see their future noise exposures reduced from an unmitigated 78 CNEL to 65 CNEL. Absorption coefficients were measured using time delay spectrometry. At lower frequencies, measured absorption coefficients were notably less than the reverberation room results advertised in the manufacturer's literature, but generally conformed with impedance tube results. At higher frequencies the correspondence between measured absorption coefficients and reverberation room results was much improved. For the actual barrier installation, unshielded residential receivers to the north are expected to experience noise exposure increases of less than 1 dB(A). This factor of increase is consistent with a finding of no impact when assessed using FRA guidelines for allowable increases of noise exposure.

A multi-scale GIS and hydrodynamic modelling approach to fish passage assessment: Clarence and Shoalhaven Rivers, NSW Australia

NASA Astrophysics Data System (ADS)

Bonetti, Rita M.; Reinfelds, Ivars V.; Butler, Gavin L.; Walsh, Chris T.; Broderick, Tony J.; Chisholm, Laurie A.

2016-05-01

Natural barriers such as waterfalls, cascades, rapids and riffles limit the dispersal and in-stream range of migratory fish, yet little is known of the interplay between these gradient dependent landforms, their hydraulic characteristics and flow rates that facilitate fish passage. The resurgence of dam construction in numerous river basins world-wide provides impetus to the development of robust techniques for assessment of the effects of downstream flow regime changes on natural fish passage barriers and associated consequences as to the length of rivers available to migratory species. This paper outlines a multi-scale technique for quantifying the relative magnitude of natural fish passage barriers in river systems and flow rates that facilitate passage by fish. First, a GIS-based approach is used to quantify channel gradients for the length of river or reach under investigation from a high resolution DEM, setting the magnitude of identified passage barriers in a longer context (tens to hundreds of km). Second, LiDAR, topographic and bathymetric survey-based hydrodynamic modelling is used to assess flow rates that can be regarded as facilitating passage across specific barriers identified by the river to reach scale gradient analysis. Examples of multi-scale approaches to fish passage assessment for flood-flow and low-flow passage issues are provided from the Clarence and Shoalhaven Rivers, NSW, Australia. In these river systems, passive acoustic telemetry data on actual movements and migrations by Australian bass (Macquaria novemaculeata) provide a means of validating modelled assessments of flow rates associated with successful fish passage across natural barriers. Analysis of actual fish movements across passage barriers in these river systems indicates that two dimensional hydraulic modelling can usefully quantify flow rates associated with the facilitation of fish passage across natural barriers by a majority of individual fishes for use in management decisions regarding environmental or instream flows.

A fine-scale assessment of using barriers to conserve native stream salmonids: a case study in Akokala Creek, Glacier National Park, USA

USGS Publications Warehouse

Muhlfeld, Clint C.; D'Angelo, Vincent S.; S. T. Kalinowski,; Landguth, Erin L.; C. C. Downs,; J. Tohtz,; Kershner, Jeffrey L.

2012-01-01

Biologists are often faced with the difficult decision in managing native salmonids of where and when to install barriers as a conservation action to prevent upstream invasion of nonnative fishes. However, fine-scale approaches to assess long-term persistence of populations within streams and watersheds chosen for isolation management are often lacking. We employed a spatially-explicit approach to evaluate stream habitat conditions, relative abundance, and genetic diversity of native westslope cutthroat trout (Oncorhynchus clarkii lewisi) within the Akokala Creek watershed in Glacier National Park- a population threatened by introgressive hybridization with nonnative rainbow trout (O. mykiss) from nearby sources. The systematic survey of 24 stream reaches showed broad overlap in fish population and suitable habitat characteristics among reaches and no natural barriers to fish migration were found. Analysis of population structure using 16 microsatellite loci showed modest amounts of genetic diversity among reaches, and that fish from Long Bow Creek were the only moderately distinct genetic group. We then used this information to assess the potential impacts of three barrier placement scenarios on long-term population persistence and genetic diversity. The two barrier placement scenarios in headwater areas generally failed to meet general persistence criteria for minimum population size (2,500 individuals, Ne = 500), maintenance of long-term genetic diversity (He), and no population subdivision. Conversely, placing a barrier near the stream mouth and selectively passing non-hybridized, migratory spawners entering Akokala Creek met all persistence criteria and may offer the best option to conserve native trout populations and life history diversity. Systematic, fine-scale stream habitat, fish distribution, and genetic assessments in streams chosen for barrier installation are needed in conjunction with broader scale assessments to understand the potential impacts of using barriers for conservation of native salmonid populations threatened by nonnative fish invasions.

Reactive barrier system for nitrate removal from mine effluents in northern Sweden: Laboratory experiments

NASA Astrophysics Data System (ADS)

Herbert, Roger

2010-05-01

Laboratory column experiments have been conducted to determine nitrate removal rates from mine effluents by denitrification, with the purpose of providing initial data for the construction of a pilot scale reactive barrier system at the Malmberget iron mine, Sweden. Experiments were conducted at several different flow rates at 5C, 10C and room temperature; annual mean temperatures at the Malmberget site lie close to 0C. Columns were filled with an organic substrate consisting of sawdust mixed with sewage sludge, the source of denitrifying bacteria, supported by oven-dried clay pellets. Apparent denitrification rates, calculated from inflow and outflow nitrate concentrations and column hydraulic residence time, ranged from 5 to 13 mg N/L/d, with the lowest rates corresponding to the 5C experiments. These rates are, however, limited to a certain degree by the low flow rate and the supply of electrons acceptors (i.e. nitrate) to denitrifying bacteria. Results from the column experiment have been used to construct a barrier system in Malmberget, Sweden. Trial runs with the pilot-scale barrier will be conducted during 2010, with the purpose of determining the performance of the barrier as mean air temperatures increase from below to above 0C and saturated flow commences in the barrier. The barrier system is constructed as a rectangular container with steel sheet walls (9m length in flow direction, 1.5m deep), and the flow rate will be adjusted to a hydraulic residence time of 1 day. The pilot-scale barrier system currently lies above ground, but a permanent barrier system would be installed below the ground surface so that the system can be maintained at positive temperatures throughout the year.

Students' Perceptions of Edmodo and Mobile Learning and Their Real Barriers towards Them

ERIC Educational Resources Information Center

Al-Said, Khaleel M.

2015-01-01

The present research aims to investigate the students' perceptions levels of Edmodo and Mobile learning and to identify the real barriers of them at Taibah University in KSA. After implemented Edmodo application as an Mlearning platform, two scales were applied on the research sample, the first scale consisted of 36 statements was constructed to…

Debris flow impact estimation on a rigid barrier

NASA Astrophysics Data System (ADS)

Vagnon, Federico; Segalini, Andrea

2016-07-01

The aim of this paper is to analyse debris flow impact against rigid and undrained barrier in order to propose a new formulation for the estimation of acting force after the flow impact to safe design protection structures. For this reason, this work concentrates on the flow impact, by performing a series of small scale tests in a specifically created flume. Flow characteristics (flow height and velocity) and applied loads (dynamic and static) on barrier were measured using four ultrasonic devices, four load cells and a contact surface pressure gauge. The results obtained were compared with main existing models and a new equation is proposed. Furthermore, a brief review of the small scale theory was provided to analyse the scale effects that can affect the results.

Statistical modeling of the long-range-dependent structure of barrier island framework geology and surface geomorphology

NASA Astrophysics Data System (ADS)

Weymer, Bradley A.; Wernette, Phillipe; Everett, Mark E.; Houser, Chris

2018-06-01

Shorelines exhibit long-range dependence (LRD) and have been shown in some environments to be described in the wave number domain by a power-law characteristic of scale independence. Recent evidence suggests that the geomorphology of barrier islands can, however, exhibit scale dependence as a result of systematic variations in the underlying framework geology. The LRD of framework geology, which influences island geomorphology and its response to storms and sea level rise, has not been previously examined. Electromagnetic induction (EMI) surveys conducted along Padre Island National Seashore (PAIS), Texas, United States, reveal that the EMI apparent conductivity (σa) signal and, by inference, the framework geology exhibits LRD at scales of up to 101 to 102 km. Our study demonstrates the utility of describing EMI σa and lidar spatial series by a fractional autoregressive integrated moving average (ARIMA) process that specifically models LRD. This method offers a robust and compact way of quantifying the geological variations along a barrier island shoreline using three statistical parameters (p, d, q). We discuss how ARIMA models that use a single parameter d provide a quantitative measure for determining free and forced barrier island evolutionary behavior across different scales. Statistical analyses at regional, intermediate, and local scales suggest that the geologic framework within an area of paleo-channels exhibits a first-order control on dune height. The exchange of sediment amongst nearshore, beach, and dune in areas outside this region are scale independent, implying that barrier islands like PAIS exhibit a combination of free and forced behaviors that affect the response of the island to sea level rise.

Al-based anti-corrosion and T-permeation barrier development for future DEMO blankets

NASA Astrophysics Data System (ADS)

Krauss, W.; Konys, J.; Holstein, N.; Zimmermann, H.

2011-10-01

In the Helium-Cooled-Liquid-Lead (HCLL) design of Test-Blanket-Modules (TBM's) for a future fusion power plant Pb-15.7Li is used as liquid breeder which is in direct contact with the structure material, e.g. EUROFER steel. Compatibility testing showed that high corrosion attack appears and that the dissolved steel components form precipitates with a high risk of system blockages. A reliable operation needs coatings as corrosion barriers. The earlier developed Hot-Dip Aluminisation (HDA) process has shown that Al-based scales can act as anti-corrosion as well as T-permeation barriers. Meanwhile two advanced electro-chemically based processes for deposition of Al-scales were successfully developed. The first (ECA = Electro-Chemical Al-deposition) is working with an organic electrolyte and the second one (ECX = Electro-Chemical-X-metal-deposition) is based on ionic liquids. Coatings in the μm-range were deposited homogeneously with exact controllable thicknesses. Metallurgical investigations showed the successful generation of protective scales and compatibility testing demonstrated the barrier function.

Geologic controls on regional and local erosion rates of three northern Gulf of Mexico barrier-island systems

USGS Publications Warehouse

Twitchell, David C.; Flocks, James G.; Pendleton, Elizabeth; Baldwin, Wayne E.

2013-01-01

The stratigraphy of sections of three barrier island systems in the northeastern Gulf of Mexico (Apalachicola, Mississippi, and Chandeleur) have been mapped using geophysical and coring techniques to assess the influence of geologic variations in barrier lithosomes and adjoining inner shelf deposits on long-term rates of shoreline change at regional and local scales. Regional scale was addressed by comparing average geologic characteristics of the three areas with mean shoreline-change rates for each area. Regionally, differences in sand volume contained within the part of the barrier lithosome above sea level, sand volume on the inner shelf, and to a lesser extent, sediment grain size correlate with shoreline change rates. Larger sand volumes and coarser grain sizes are found where erosion rates are lower. Local scale was addressed by comparing alongshore variations in barrier island and inner shelf geology with alongshore variations in shoreline change. Locally, long-term shoreline change rates are highest directly shoreward of paleovalleys exposed on the inner shelf. While geology is not the sole explanation for observed differences in shoreline change along these three coastal regions, it is a significant contributor to change variability.

Factor Structure of the Condoms Barriers Scale with a Sample of Men at High Risk for HIV

ERIC Educational Resources Information Center

Doyle, Suzanne R.; Calsyn, Donald A.; Ball, Samuel A.

2009-01-01

This study assesses the psychometric properties of the Condom Barriers Scale (CBS), an instrument originally designed to measure women's perceptions and attitudes regarding male condom use, with a sample of men at high risk for human immunodeficiency virus (HIV). Participants include 590 male patients in drug abuse treatment involved in a…

Transport Barriers in Bootstrap Driven Tokamaks

NASA Astrophysics Data System (ADS)

Staebler, Gary

2017-10-01

Maximizing the bootstrap current in a tokamak, so that it drives a high fraction of the total current, reduces the external power required to drive current by other means. Improved energy confinement, relative to empirical scaling laws, enables a reactor to more fully take advantage of the bootstrap driven tokamak. Experiments have demonstrated improved energy confinement due to the spontaneous formation of an internal transport barrier in high bootstrap fraction discharges. Gyrokinetic analysis, and quasilinear predictive modeling, demonstrates that the observed transport barrier is due to the suppression of turbulence primarily due to the large Shafranov shift. ExB velocity shear does not play a significant role in the transport barrier due to the high safety factor. It will be shown, that the Shafranov shift can produce a bifurcation to improved confinement in regions of positive magnetic shear or a continuous reduction in transport for weak or negative magnetic shear. Operation at high safety factor lowers the pressure gradient threshold for the Shafranov shift driven barrier formation. The ion energy transport is reduced to neoclassical and electron energy and particle transport is reduced, but still turbulent, within the barrier. Deeper into the plasma, very large levels of electron transport are observed. The observed electron temperature profile is shown to be close to the threshold for the electron temperature gradient (ETG) mode. A large ETG driven energy transport is qualitatively consistent with recent multi-scale gyrokinetic simulations showing that reducing the ion scale turbulence can lead to large increase in the electron scale transport. A new saturation model for the quasilinear TGLF transport code, that fits these multi-scale gyrokinetic simulations, can match the data if the impact of zonal flow mixing on the ETG modes is reduced at high safety factor. This work was supported by the U.S. Department of Energy under DE-FG02-95ER54309 and DE-FC02-04ER54698.

Motivators and barriers of a Healthy Lifestyle Scale: development and psychometric characteristics.

PubMed

Downes, Loureen

2008-01-01

Black individuals suffer disproportionately from diseases that are preventable by lifestyle choices. The purpose of this study was to test the internal consistency and construct validity of the newly devised instrument, Motivators and Barriers of a Healthy Lifestyle Scale (MABS). The MABS was administered to 109 community-dwelling, adult Blacks. Content validity was supported through review of the literature and the judgment of three content experts. Exploratory factor analysis supported the two dimensions, that is, motivators and barriers. The Cronbach's alphas for the motivators and barriers dimensions were .88 and .90, respectively. Results provide initial evidence that the MABS is a valid, internally consistent measure of factors that motivate or inhibit healthy lifestyle behaviors. Screening with the MABS could encourage more focused health promotion discussions between patients and practitioners.

Memory-induced acceleration and slowdown of barrier crossing

NASA Astrophysics Data System (ADS)

Kappler, Julian; Daldrop, Jan O.; Brünig, Florian N.; Boehle, Moritz D.; Netz, Roland R.

2018-01-01

We study the mean first-passage time τMFP for the barrier crossing of a single massive particle with non-Markovian memory by Langevin simulations in one dimension. In the Markovian limit of short memory time τΓ, the expected Kramers turnover between the overdamped (high-friction) and the inertial (low-friction) limits is recovered. Compared to the Markovian case, we find barrier crossing to be accelerated for intermediate memory time, while for long memory time, barrier crossing is slowed down and τMFP increases with τΓ as a power law τM F P˜τΓ2. Both effects are derived from an asymptotic propagator analysis: while barrier crossing acceleration at intermediate memory can be understood as an effective particle mass reduction, slowing down for long memory is caused by the slow kinetics of energy diffusion. A simple and globally accurate heuristic formula for τMFP in terms of all relevant time scales of the system is presented and used to establish a scaling diagram featuring the Markovian overdamped and the Markovian inertial regimes, as well as the non-Markovian intermediate memory time regime where barrier crossing is accelerated and the non-Markovian long memory time regime where barrier crossing is slowed down.

Barriers to Implementation of Optimal Laboratory Biosafety Practices in Pakistan

PubMed Central

Shafaq, Humaira; Hasan, Rumina; Qureshi, Shahida M.; Dojki, Maqboola; Hughes, Molly A.; Zaidi, Anita K. M.; Khan, Erum

2016-01-01

The primary goal of biosafety education is to ensure safe practices among workers in biomedical laboratories. Despite several educational workshops by the Pakistan Biological Safety Association (PBSA), compliance with safe practices among laboratory workers remains low. To determine barriers to implementation of recommended biosafety practices among biomedical laboratory workers in Pakistan, we conducted a questionnaire-based survey of participants attending 2 workshops focusing on biosafety practices in Karachi and Lahore in February 2015. Questionnaires were developed by modifying the BARRIERS scale in which respondents are required to rate barriers on a 1-4 scale. Nineteen of the original 29 barriers were included and subcategorized into 4 groups: awareness, material quality, presentation, and workplace barriers. Workshops were attended by 64 participants. Among barriers that were rated as moderate to great barriers by at least 50% of respondents were: lack of time to read biosafety guidelines (workplace subscale), lack of staff authorization to change/improve practice (workplace subscale), no career or self-improvement advantages to the staff for implementing optimal practices (workplace subscale), and unclear practice implications (presentation subscale). A lack of recognition for employees' rights and benefits in the workplace was found to be a predominant reason for a lack of compliance. Based on perceived barriers, substantial improvement in work environment, worker facilitation, and enabling are needed for achieving improved or optimal biosafety practices in Pakistan. PMID:27400192

Perceptıon scale of barrıers to contraceptıve use: a methodologıcal study.

PubMed

Sen, Selma; Cetinkaya, Aynur; Cavuslar, Aysel

2017-01-01

The objective of this study was to design and develop the Perception Scale of Barriers to Contraceptive Use (PSBCU) as a measurement tool for the qualitative assessment of the barriers and obstacles women perceived with regard to contraceptive use or low rates of contraceptive use in women using family planning services. The data for this methodological study were collected using the face-to-face interview technique from 320 married women between the ages of 15-49 who were attending clinics at the Hafsa Sultan Hospital, CBU. The data collection tools used in the study, which was carried out from May to September 2014, were the "Introductory Information Form" and the "Perception Scale of Barriers to Contraceptive Use". Language validity and construct validity (explanatory factor analysis) were applied in order to test the validity of the Perception Scale of Barriers to Contraceptive Use. Kaiser Meier Olkin (KMO) analysis was performed to determine the availability of the scale for the size of participants. The sample adequacy calculated as the KMO value was 0.916 and the Bartlett's Test of Sphericity (X 2  = 6721.793 p  < 0.000) sample size analysis value was found to be sufficient for factor analysis. The total Cronbach's Alpha coefficient of 34 items which included three factors explaining 54.95% of the variance after Varimax rotation was calculated to be 0.95. The largest factor was the "cognitive domain" explaining 18.89% of the variance, followed by the "emotional domain" explaining 18.05% of the variance, and finally the "social domain" explaining 18.01% of the variance. Item-total score correlation coefficients of scale items were found to be between 0.54 and 0.83. The study demonstrateded that the "Perception Scale of Barriers to Contraceptive Use" was valid and reliable. We believe that the scale is suitable for use by women in a family planning education and training programs in order to evaluate their situation. It should also be assessed for validity and reliability for different groups (adolescents, men, etc.).

REMEDIATION OF TCE-CONTAMINATED GROUNDWATER BY A PERMEABLE REACTIVE BARRIER FILLED WITH PLANT MULCH (BIOWALL)

EPA Science Inventory

A pilot-scale permeable reactive barrier filled with plant mulch was installed at Altus Air Force Base (in Oklahoma, USA) to treat trichloroethylene (TCE) contamination in ground water emanating from a landfill. The barrier was constructed in June 2002. It was 139 meters long, 7 ...

Barriers to hydroxyurea adherence and health-related quality of life in adolescents and young adults with sickle cell disease.

PubMed

Badawy, Sherif M; Thompson, Alexis A; Penedo, Frank J; Lai, Jin-Shei; Rychlik, Karen; Liem, Robert I

2017-06-01

To identify barriers to hydroxyurea adherence (negative beliefs, access, and/or recall barriers), and their relationship to adherence rates and health-related quality of life (HRQOL) among adolescents and young adults (AYA) with sickle cell disease (SCD). A cross-sectional survey was administered to 34 AYAs (12-22 years old) in SCD clinics from January to December 2015. Study measures included Brief Medication Questionnaire, Modified Morisky Adherence Scale 8-items, visual analog scale, and Patient Reported Outcomes Measurement Information System. Participants (59% male; 91% Black) had a median age of 13.5 years (IQR 12-18). Participants reported negative beliefs (32%), recall barriers (44%), and access barriers (32%). Participants with recall barriers reported worse pain (P=.02), fatigue (P=.05), and depression (P=.05). The number of adherence barriers inversely correlated with adherence level using ©MMAS-8 (r s =-.38, P=.02) and VAS dose (r s =-.25, P=.14) as well as MCV (r s =-.45, P=.01) and HbF% (r s =-.36, P=.05), suggesting higher hydroxyurea adherence in patients with fewer barriers. Patients with fewer barriers to hydroxyurea adherence were more likely to have higher adherence rates and better HRQOL scores. Routine assessment of hydroxyurea adherence and its related barriers could provide actionable information to improve adherence rates, HRQOL, and other clinical outcomes. © 2017 The Authors. European Journal of Haematology Published by John Wiley & Sons Ltd.

Implementing the Fatigue Guidelines at One NCCN Member Institution: Process and Outcomes

PubMed Central

Borneman, Tami; Piper, Barbara F.; Sun, Virginia Chih-Yi; Koczywas, Marianna; Uman, Gwen; Ferrell, Betty

2008-01-01

Fatigue, despite being the most common and distressing symptom in cancer, is often unrelieved because of numerous patient provider, and system barriers. The overall purpose of this 5-year prospective clinical trial is to translate the NCCN Cancer-Related Fatigue Clinical Practice Guidelines in Oncology and NCCN Adult Cancer Pain Clinical Practice Guidelines in Oncology into practice and develop a translational interventional model that can be replicated across settings. This article focuses on one NCCN member institution’s experience related to the first phase of the NCCN Cancer-Related Fatigue Guidelines implementation, describing usual care compared with evidence-based guidelines. Phase 1 of this 3-phased clinical trial compared the usual care of fatigue with that administered according to the NCCN guidelines. Eligibility criteria included age 18 years or older; English-speaking; diagnosed with breast, lung, colon, or prostate cancer; and fatigue and/or pain ratings of 4 or more on a 0 to 10 screening scale. Research nurses screened all available subjects in a cancer center medical oncology clinic to identify those meeting these criteria. Instruments included the Piper Fatigue Scale, a Fatigue Barriers Scale, a Fatigue Knowledge Scale, and a Fatigue Chart Audit Tool. Descriptive and inferential statistics were used in data analysis. At baseline, 45 patients had fatigue only (≥4) and 24 had both fatigue and pain (≥4). This combined sample (N = 69) was predominantly Caucasian (65%), female (63%), an average of 60 years old, diagnosed with stage 3 or 4 breast cancer, and undergoing treatment (82%). The most common barriers noted were patients’ belief that physicians would introduce the subject of fatigue if it was important (patient barrier); lack of fatigue documentation (professional barrier); and lack of supportive care referrals (system barrier). Findings showed several patient, professional, and system barriers that distinguish usual care from that recommended by the NCCN Cancer-Related Fatigue Guidelines. Phase 2, the intervention model, is designed to decrease these barriers and improve patient outcomes overtime, and is in progress. PMID:18053431

Barriers Inhibiting Inquiry-Based Science Teaching and Potential Solutions: Perceptions of Positively Inclined Early Adopters

NASA Astrophysics Data System (ADS)

Fitzgerald, Michael; Danaia, Lena; McKinnon, David H.

2017-07-01

In recent years, calls for the adoption of inquiry-based pedagogies in the science classroom have formed a part of the recommendations for large-scale high school science reforms. However, these pedagogies have been problematic to implement at scale. This research explores the perceptions of 34 positively inclined early-adopter teachers in relation to their implementation of inquiry-based pedagogies. The teachers were part of a large-scale Australian high school intervention project based around astronomy. In a series of semi-structured interviews, the teachers identified a number of common barriers that prevented them from implementing inquiry-based approaches. The most important barriers identified include the extreme time restrictions on all scales, the poverty of their common professional development experiences, their lack of good models and definitions for what inquiry-based teaching actually is, and the lack of good resources enabling the capacity for change. Implications for expectations of teachers and their professional learning during educational reform and curriculum change are discussed.

The psychometric properties of exercise benefits/barriers scale among women

PubMed Central

Farahani, Leila Amiri; Parvizy, Soroor; Mohammadi, Eesa; Asadi-Lari, Mohsen; Kazemnejad, Anoshiravan; Hasanpoor-Azgahdy, Seyede Batool; Taghizadeh, Ziba

2017-01-01

Background and objective Despite the numerous health benefits of regular physical activity (PA), physical inactivity is a major health issue among women. The goal of the current study was to measure the validity and reliability assessment of the exercise benefits/barriers scale among women between the ages of 18 and 65 years. This study was carried out among women residing in Khoramroudi neighborhood in Tehran between December 2013 and February 2014. Methods In this descriptive, methodological study, 278 women residing in Khoramroudi neighborhood in Tehran between December 2013 and February 2014 completed three questionnaires: the demographic data form, the Exercise Benefits/Barriers Scale. The construct validity, internal consistency, and stability of the study were measured by confirmatory factor analyses, Cronbach’s alpha, and Spearman Brown correlation coefficient by using SPSS 21 and LISREL 8.80, respectively. Results The confirmatory factor analysis showed the Persian version of EBBS was structured well. The Cronbach’s alpha coefficients for the total scale and its subscales were 0.927, 0.94 and 0.82, respectively. Spearman Brown correlation coefficient also showed good test-retest reliability. Conclusion The results of this study verified the reliability and validity of the applied instrument and introduced it as a tool to measure the benefits and barriers of physical activity among Iranian women. PMID:28894535

The psychometric properties of exercise benefits/barriers scale among women.

PubMed

Farahani, Leila Amiri; Parvizy, Soroor; Mohammadi, Eesa; Asadi-Lari, Mohsen; Kazemnejad, Anoshiravan; Hasanpoor-Azgahdy, Seyede Batool; Taghizadeh, Ziba

2017-07-01

Despite the numerous health benefits of regular physical activity (PA), physical inactivity is a major health issue among women. The goal of the current study was to measure the validity and reliability assessment of the exercise benefits/barriers scale among women between the ages of 18 and 65 years. This study was carried out among women residing in Khoramroudi neighborhood in Tehran between December 2013 and February 2014. In this descriptive, methodological study, 278 women residing in Khoramroudi neighborhood in Tehran between December 2013 and February 2014 completed three questionnaires: the demographic data form, the Exercise Benefits/Barriers Scale. The construct validity, internal consistency, and stability of the study were measured by confirmatory factor analyses, Cronbach's alpha, and Spearman Brown correlation coefficient by using SPSS 21 and LISREL 8.80, respectively. The confirmatory factor analysis showed the Persian version of EBBS was structured well. The Cronbach's alpha coefficients for the total scale and its subscales were 0.927, 0.94 and 0.82, respectively. Spearman Brown correlation coefficient also showed good test-retest reliability. The results of this study verified the reliability and validity of the applied instrument and introduced it as a tool to measure the benefits and barriers of physical activity among Iranian women.

Debris Flow Risk mitigation by the means of flexible barriers. Experimental and field tests.

NASA Astrophysics Data System (ADS)

Canelli, L.; Ferrero, A. M.; Segalini, A.

2012-04-01

Debris flow risk mitigation using net barriers is an option that was not considered until few years ago, probably because of the lack of scientific evidences about their efficiency and solid guidelines for their design and construction. On site evidences (Segalini et al, 2008) showed that a rock fall deformable barrier can efficiently intercept the whole volume or just a portion of the mobilized debris without losing its stability and efficiency, actually performing a different task form that it was originally designed for. Although the final purpose of both types of barriers (rock fall and debris) is to reduce the impact energy of the moving mass by dissipating impact energy through the deformation of the net and of the dissipating elements, it is noteworthy that the physics of the impact is extremely different between the two phenomena. The rock fall barrier needs to dissipate the energy of a single block generally concentrated on the center of the net panel (design conditions). The debris flow barrier, generally installed inside a debris channel, should be able to dissipate the impact energy that the debris induces across the whole section of the channel. Moreover, the recurring characteristic of the debris flows will cause multiple impact on the barrier and therefore, the structure should be able to absorb a significant amount of energy even if partially filled and considerably deformed. In order to introduce useful guidelines for the design and production of debris flow net barriers, this paper describes: 1. Part of the results obtained from the laboratory experiment carried out in a scaled channel and aimed to estimate the most realistic thrust vs time relationship induced by a debris flow on a deformable and rigid structure; these results were partially presented last year at the EGU 2011; 2. A large scale field test carried out in a quarry located in Tambre d'Alpago (Belluno Province) on the Eastern Italian Dolomites for the analysis of the behavior of a real scale deformable net barrier subjected to recurring impacts of small volumes, substantially dry, debris flows until the complete filling up of the channel. Laboratory tests were carried out using a small scale channel (40 cm wide channel and 4 m long) designed and installed at University of Parma in which were triggered flows of water saturated sand impacting with different typologies of barriers installed in order to measure the impact force of the generated flow. The field test has been conducted by artificially mobilizing volumes of quarry debris along a 50 m long and 2 m wide channel at the end of which a real scale deformable net barrier was installed. The impacts were monitored using five high speed video cameras, the deformation progress of the barrier induced by the impacts was obtained using two high shutter speed cameras configured and synchronized for a stereoscopic restitution. Forces on the structural steel cables where measured by installing five load cells between the cable and its foundation. Results obtained are presented and compared with the relevant literature.

Quantitative data analysis of perceived barriers and motivators to physical activity in stroke survivors.

PubMed

Nicholson, S L; Greig, C A; Sniehotta, F; Johnston, M; Lewis, S J; McMurdo, M E; Johnston, D; Scopes, J; Mead, G E

2017-09-01

Levels of physical activity after stroke are low, despite multiple health benefits. We explored stroke survivors' perceived barriers, motivators, self-efficacy and intention to physical activity. Fifty independently mobile stroke survivors were recruited prior to hospital discharge. Participants rated nine possible motivators and four possible barriers based on the Mutrie Scale, as having 'no influence', 'some influence' or 'a major influence' on physical activity. Participants also rated their self-efficacy and intention to increasing walking. The most common motivator was 'physical activity is good for health' [34 (68%)]. The most common barrier was 'feeling too tired' [24 (48%)]. Intention and self-efficacy were high. Self-efficacy was graded as either 4 or 5 (highly confident) on a five-point scale by [34 (68%)] participants, while 42 (84%) 'strongly agreed' or 'agreed' that they intended to increase their walking. Participants felt capable of increasing physical activity but fatigue was often perceived as a barrier to physical activity. This needs to be considered when encouraging stroke survivors to be more active.

Perceived Exercise Self-Efficacy, Benefits and Barriers, and Commitment to a Plan for Exercise among Jordanians with Chronic Illnesses.

PubMed

Darawad, Muhammad W; Khalil, Amani A; Hamdan-Mansour, Ayman M; Nofal, Basema M

2016-11-01

To explore Jordanian chronic illnesses patients' perceived exercise self-efficacy, benefits and barriers, and commitment to exercise planning, and to assess the relationship between those variables. Descriptive cross-sectional design. Data were collected from a convenience sample of 402 outpatient Jordanians with chronic illnesses, using Exercise Self-Efficacy Scale, Exercise Benefits and Barriers Scale, and Commitment to a Plan for Exercise Scale. The average BMI was 28.3, and exercise period 3.2 hours/ week. Participants reported moderate perceived self-efficacy (M= 47.5%, SD= 11.7), commitment to exercise planning (M=2.0/3, SD=0.3), exercise barriers (M=2.4/4, SD=0.3), and benefits (M=2.3/4, SD=0.3). Commitment to exercise planning had a significant correlation with barriers (r=0.11) and benefits (r=0.10). Self-efficacy was not found to correlate with other variables. Even though participants reported higher perceived self-efficacy and commitment to exercise plan than that reported in literature, they were found to be overweight and inactive, which indicates the importance of such study. Exercise education programs are needed taking into considerations patients' individual differences. However, the broad grouping of diseases may not produce a homogenous sample, for which disease categories are recommended in future studies. Patients with chronic illness need more encouragement to engage themselves in exercise practices. Exercise educational program for patients with chronic illnesses should consider patients' reported exercise benefits and barriers. © 2014 Association of Rehabilitation Nurses.

Introduction to the special issue on discontinuity of fluvial systems

NASA Astrophysics Data System (ADS)

Burchsted, Denise; Daniels, Melinda; Wohl, Ellen E.

2014-01-01

Fluvial systems include natural and human-created barriers that modify local base level; as such, these discontinuities alter the longitudinal flux of water and sediment by storing, releasing, or changing the flow path of those materials. Even in the absence of distinct barriers, fluvial systems are typically discontinuous and patchy. The size of fluvial discontinuities ranges across scales from 100 m, such as riffles, to 104 m, such as lava dams or major landslides. The frequency of occurrence appears to be inversely related to size, with creation and failure of the small features, such as beaver dams, occurring on a time scale of 100 to 101 years and a frequency of occurrence at scales as low as 101 m. In contrast, larger scale discontinuities, such as lava dams, can last for time scales up to 105 years and have a frequency of occurrence of approximately 104 m. The heterogeneity generated by features is an essential part of river networks and should be considered as part of river management. Therefore, we suggest that "natural" dams are a useful analog for human dams when evaluating options for river restoration. This collection of papers on the studies of natural dams includes bedrock barriers, log jams and beaver dams. The collection also addresses the discontinuity generated by a floodplain — in the absence of an obvious barrier in the channel — and tools for evaluation of riverbed heterogeneity. It is completed with a study of impact of human dams on floodplain sedimentation. These papers will help geomorphologists and river managers understand the factors that control river heterogeneity across scales and around the world.

How thin barrier metal can be used to prevent Co diffusion in the modern integrated circuits?

NASA Astrophysics Data System (ADS)

Dixit, Hemant; Konar, Aniruddha; Pandey, Rajan; Ethirajan, Tamilmani

2017-11-01

In modern integrated circuits (ICs), billions of transistors are connected to each other via thin metal layers (e.g. copper, cobalt, etc) known as interconnects. At elevated process temperatures, inter-diffusion of atomic species can occur among these metal layers, causing sub-optimal performance of interconnects, which may lead to the failure of an IC. Thus, typically a thin barrier metal layer is used to prevent the inter-diffusion of atomic species within interconnects. For ICs with sub-10 nm transistors (10 nm technology node), the design rule (thickness scaling) demands the thinnest possible barrier layer. Therefore, here we investigate the critical thickness of a titanium-nitride (TiN) barrier that can prevent the cobalt diffusion using multi-scale modeling and simulations. First, we compute the Co diffusion barrier in crystalline and amorphous TiN with the nudged elastic band method within first-principles density functional theory simulations. Later, using the calculated activation energy barriers, we quantify the Co diffusion length in the TiN metal layer with the help of kinetic Monte Carlo simulations. Such a multi-scale modelling approach yields an exact critical thickness of the metal layer sufficient to prevent the Co diffusion in IC interconnects. We obtain a diffusion length of a maximum of 2 nm for a typical process of thermal annealing at 400 °C for 30 min. Our study thus provides useful physical insights for the Co diffusion in the TiN layer and further quantifies the critical thickness (~2 nm) to which the metal barrier layer can be thinned down for sub-10 nm ICs.

Adapting to climate change by water management organisations: Enablers and barriers

NASA Astrophysics Data System (ADS)

Azhoni, Adani; Jude, Simon; Holman, Ian

2018-04-01

Climate change will be particularly experienced though the medium of water. Water organisations, that are managing societal and ecological needs for water, are therefore likely to experience the impact the most. This study reviews the current literature regarding adaptation to climate change by water management organisations and associated barriers. Literature on adaptive capacity is growing and a general consensus is emerging on the determinants of adaptive capacity, although variations exist regarding how it is to be evaluated, enhanced and applied to policy making due to its dynamic, contextual and latent nature. Since adaptive capacity is hard to measure and successful adaptation difficult to define, some studies focus on the existence of adaptation attributes of organisations. Studies reporting successful adaptation are minimal and barriers of adaptation are being discovered as adaptation research transitions into implementation. But the root causes of these barriers are often overlooked and the interconnectedness of the barriers is poorly addressed. Increasingly, combining top-down and bottom-up approaches to adaptation is being recommended due to the limitations of each. However, knowledge regarding how organisations operating at different scales can enhance adaptive capacity of other organisations operating at another scale is lacking due to the few studies of inter-organisational networks across scales. Social networks among actors are recognised as a key factor to enable adaptation. However, network studies generally focus on individual actors and rarely between public agencies/organisations. Moreover, the current literature is inadequate to understand the relationship between adaptation enabling characteristics, barriers and adaptation manifestation. The review demonstrates that research on understanding the emergence and sustenance of barriers is urgently required. Addressing these knowledge gaps will help to improve the design of adaptation strategies, thereby improving the ability of water management to address the ongoing challenges of climate change.

Use of vegetable oil in a pilot-scale denitrifying barrier

NASA Astrophysics Data System (ADS)

Hunter, William J.

2001-12-01

Nitrate in drinking water is a hazard to both humans and animals. Contaminated water can cause methemoglobinemia and may pose a cancer risk. Permeable barriers containing innocuous oils, which stimulate denitrification, can remove nitrate from flowing groundwater. For this study, a sand tank (1.1×2.0×0.085 m in size) containing sand was used as a one-dimensional open-top scale model of an aquifer. A meter-long area near the center of the tank contained sand coated with soybean oil. This region served as a permeable denitrifying barrier. Water containing 20 mg l -1 nitrate-N was pumped through the barrier at a high flow rate, 1112 l week -1, for 30 weeks. During the 30-week study, the barrier removed 39% of the total nitrate-N present in the water. The barrier was most efficient during the first 10 weeks of the study when almost all of the nitrate and nitrogen was removed. Efficiency declined with time so that by week 30 almost no nitrate was removed by the system. Nitrite levels in the effluent water remained low throughout the study. Barriers could be used to protect groundwater from nitrate contamination or for the in situ treatment of contaminated water. At the low flow rates that exist in most aquifers, such barriers should be effective at removing nitrate from groundwater for a much longer period of time.

Emergency nurses' knowledge of perceived barriers in pain management in Taiwan.

PubMed

Tsai, Feng-Ching; Tsai, Yun-Fang; Chien, Chih-Cheng; Lin, Chia-Chin

2007-11-01

To explore knowledge of and perceived barriers to pain management among emergency nurses in Taiwan. Pain is the most common patient complaint in emergency departments. Quality care of these patients depends on the pain knowledge and pain management skills of emergency nurses. However, no studies have explored emergency nurses' knowledge of and perceived barriers to pain management in Taiwan. Nurse subjects (n = 249) were recruited from nine hospitals chosen by stratified sampling across Taiwan. Data were collected using the Nurses' Knowledge and Attitudes Survey-Taiwanese version, a scale to assess perceived barriers to pain management and a background information form. The overall average correct response rate for the knowledge scale was 49.2%, with a range of 4.8-89.2% for each survey question. The top barrier to managing pain was identified by these nurses as 'the responsibility of caring for other acutely ill patients in addition to a patient with pain. Knowledge of pain management had a significant, negative relationship with perceived barriers to pain management and a significant, positive relationship with extent of clinical care experience and total hours of prior pain management education. In addition, scores for knowledge and perceived barriers differed significantly by the nursing clinical ladder. Perceived barriers also differed significantly by hospital accreditation category. Our results indicate an urgent need to strengthen pain education for emergency nurses in Taiwan. The pain education should target knowledge deficits and barriers to changing pain management approaches for Taiwanese emergency nurses.

Current Barriers to Large-scale Interoperability of Traceability Technology in the Seafood Sector.

PubMed

Hardt, Marah J; Flett, Keith; Howell, Colleen J

2017-08-01

Interoperability is a critical component of full-chain digital traceability, but is almost nonexistent in the seafood industry. Using both quantitative and qualitative methodology, this study explores the barriers impeding progress toward large-scale interoperability among digital traceability systems in the seafood sector from the perspectives of seafood companies, technology vendors, and supply chains as a whole. We highlight lessons from recent research and field work focused on implementing traceability across full supply chains and make some recommendations for next steps in terms of overcoming challenges and scaling current efforts. © 2017 Institute of Food Technologists®.

The Danish Barriers Questionnaire-II: preliminary validation in cancer pain patients.

PubMed

Jacobsen, Ramune; Møldrup, Claus; Christrup, Lona; Sjøgren, Per; Hansen, Ole Bo

2009-01-01

The objective of this study was to examine the psychometric properties of the Danish version of the Barriers Questionnaire-II (DBQ-II). The validated Norwegian version of the DBQ-II was translated into Danish. Cancer patients for the study were recruited from specialized pain management facilities. Thirty-three patients responded to the DBQ-II, Hospital Anxiety and Depression Scale, and Brief Pain Inventory pain severity scale. A factor analysis of the DBQ-II resulted in six scales. Scale one, Fatalism, consisted of three items addressing fatalistic beliefs regarding cancer pain management. Scale two, Immune System, consisted of three items addressing the belief that pain medications harm the immune system. Scale three, Monitor, consisted of three items addressing the fear that pain medicine masks changes in one's body. Scale four, Communication, consisted of five items addressing the concern that reports of pain distract the physician from treating the cancer, and the belief that "good" patients do not complain. Scale five, Addiction, consisted of two items addressing the fear of becoming addicted to pain medication. Finally, scale six, Tolerance, consisted of three items addressing the fear of getting tolerant to analgesic effect of pain medicine. Items related to medication side effects were analyzed as separate units. The DBQ-II total had an internal consistency of 0.87. The DBQ-II total score was related to measures of pain relief and anxiety. The DBQ-II seems to be a reliable and valid measure of the barriers to pain management among Danish cancer patients.

Traffic barriers on curves, curbs, and slopes

DOT National Transportation Integrated Search

1993-10-01

A review of past research and accident databases, conduct of full-scale testing, and computer simulation and validation were conducted in an attempt to develop definitive guidelines for the placement of traffic barriers on curves, curbs, and slopes.

Simplified Impact Testing of Traffic Barrier Systems (Phase I)

DOT National Transportation Integrated Search

2003-06-01

A simplified impact test configuration was developed to provide a preliminary, economical means of assessing prototype traffic barriers before proceeding to full-scale federal testing. Specifically, the test was configured to assess the federal crite...

Assessing systemic barriers to permanency achievement for children in out-of-home care: development of the child permanency barriers scale.

PubMed

Murphy, April L; Van Zyl, Riaan; Collins-Camargo, Crystal; Sullivan, Dana

2012-01-01

State and local child welfare agencies are engaged in multiple efforts to enact systems change to improve outcomes, particularly in regard to achievement of child permanency. The Child and Family Services Review process, conducted by the Administration Children and Families, requires states to implement program improvement plans designed to improve outcomes for which they are not meeting national standards. However, a tool has not been demonstrated as useful in assessing the barriers to achievement of permanency across the out-of-home service continuum, from recruitment of families to placement stability. This article reports on the development and refinement of such a tool in one Midwestern state. The Child Permanency Barriers Scale has four factors: kinship, placement and matching, adequate services and resources, and communication and collaboration. Implications for use in state-specific and multisystem assessment and system reform are discussed.

A 3D Real-Scale, Biomimetic, and Biohybrid Model of the Blood-Brain Barrier Fabricated through Two-Photon Lithography.

PubMed

Marino, Attilio; Tricinci, Omar; Battaglini, Matteo; Filippeschi, Carlo; Mattoli, Virgilio; Sinibaldi, Edoardo; Ciofani, Gianni

2018-02-01

The investigation of the crossing of exogenous substances through the blood-brain barrier (BBB) is object of intensive research in biomedicine, and one of the main obstacles for reliable in vitro evaluations is represented by the difficulties at the base of developing realistic models of the barrier, which could resemble as most accurately as possible the in vivo environment. Here, for the first time, a 1:1 scale, biomimetic, and biohybrid BBB model is proposed. Microtubes inspired to the brain capillaries were fabricated through two-photon lithography and used as scaffolds for the co-culturing of endothelial-like bEnd.3 and U87 glioblastoma cells. The constructs show the maturation of tight junctions, good performances in terms of hindering dextran diffusion through the barrier, and a satisfactory trans-endothelial electrical resistance. Moreover, a mathematical model is developed, which assists in both the design of the 3D microfluidic chip and its characterization. Overall, these results show the effective formation of a bioinspired cellular barrier based on microtubes reproducing brain microcapillaries to scale. This system will be exploited as a realistic in vitro model for the investigation of BBB crossing of nanomaterials and drugs, envisaging therapeutic and diagnostic applications for several brain pathologies, including brain cancer. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Barriers associated with reduced physical activity in COPD patients.

PubMed

Amorim, Priscila Batista; Stelmach, Rafael; Carvalho, Celso Ricardo Fernandes; Fernandes, Frederico Leon Arrabal; Carvalho-Pinto, Regina Maria; Cukier, Alberto

2014-10-01

To evaluate the ability of COPD patients to perform activities of daily living (ADL); to identify barriers that prevent these individuals from performing ADL; and to correlate those barriers with dyspnea severity, six-minute walk test (6MWT), and an ADL limitation score. In COPD patients and healthy, age-matched controls, the number of steps, the distance walked, and walking time were recorded with a triaxial accelerometer, for seven consecutive days. A questionnaire regarding perceived barriers and the London Chest Activity of Daily Living (LCADL) scale were used in order to identify the factors that prevent the performance of ADL. The severity of dyspnea was assessed with two scales, whereas submaximal exercise capacity was determined on the basis of the 6MWT. We evaluated 40 COPD patients and 40 controls. In comparison with the control values, the mean walk time was significantly shorter for COPD patients (68.5 ± 25.8 min/day vs. 105.2 ± 49.4 min/day; p < 0.001), as was the distance walked (3.9 ± 1.9 km/day vs. 6.4 ± 3.2 km/day; p < 0.001). The COPD patients also walked fewer steps/day. The most common self-reported barriers to performing ADL were lack of infrastructure, social influences, and lack of willpower. The 6MWT distance correlated with the results obtained with the accelerometer but not with the LCADL scale results. Patients with COPD are less active than are healthy adults of a comparable age. Physical inactivity and the barriers to performing ADL have immediate implications for clinical practice, calling for early intervention measures.

Barriers to physical activity and healthy eating in young breast cancer survivors: modifiable risk factors and associations with body mass index.

PubMed

Ventura, Emily E; Ganz, Patricia A; Bower, Julienne E; Abascal, Liana; Petersen, Laura; Stanton, Annette L; Crespi, Catherine M

2013-11-01

Physical activity (PA) and healthy eating (HE) are important behaviors to encourage in breast cancer survivors (BCS). We examined associations between various factors and barriers to PA (BPA) and barriers to HE (BHE), as well as relationships between barriers and body mass index (BMI) in younger BCS. Self-reported data from 162 BCS (mean age 48 years) were used. BPA were assessed with a 21-item scale and BHE with a 19-item scale. Participants were classified as high or low on each scale. Sociodemographic, medical, and psychosocial characteristics were compared by high/low barriers. Correlates of continuous BPA and BHE were assessed as were associations among BHE, BPA, and BMI. 61 % of participants were characterized as having low BHE and low BPA; 12 % were high for both. High BHE/high BPA participants had the least favorable scores for depression, perceived stress, social support, fatigue, bladder control, and weight problems. Factors associated with BHE were lower education, higher perceived stress, and more severe weight problems. Factors associated with BPA were more severe bladder control problems and lower physical well-being. Higher BHE and BPA were significantly and uniquely associated with higher BMI, controlling for covariates. Several biopsychosocial factors (e.g., depression, stress, and fatigue) characterize young BCS who experience barriers to both HE and PA. The correlates of BHE and BPA are distinct. Both BHE and BPA are associated with BMI. These results should be considered in designing interventions for younger women with breast cancer.

Translation, Cross-cultural Adaptation and Psychometric Validation of the Korean-Language Cardiac Rehabilitation Barriers Scale (CRBS-K).

PubMed

Baek, Sora; Park, Hee-Won; Lee, Yookyung; Grace, Sherry L; Kim, Won-Seok

2017-10-01

To perform a translation and cross-cultural adaptation of the Cardiac Rehabilitation Barriers Scale (CRBS) for use in Korea, followed by psychometric validation. The CRBS was developed to assess patients' perception of the degree to which patient, provider and health system-level barriers affect their cardiac rehabilitation (CR) participation. The CRBS consists of 21 items (barriers to adherence) rated on a 5-point Likert scale. The first phase was to translate and cross-culturally adapt the CRBS to the Korean language. After back-translation, both versions were reviewed by a committee. The face validity was assessed in a sample of Korean patients (n=53) with history of acute myocardial infarction that did not participate in CR through semi-structured interviews. The second phase was to assess the construct and criterion validity of the Korean translation as well as internal reliability, through administration of the translated version in 104 patients, principle component analysis with varimax rotation and cross-referencing against CR use, respectively. The length, readability, and clarity of the questionnaire were rated well, demonstrating face validity. Analysis revealed a six-factor solution, demonstrating construct validity. Cronbach's alpha was greater than 0.65. Barriers rated highest included not knowing about CR and not being contacted by a program. The mean CRBS score was significantly higher among non-attendees (2.71±0.26) than CR attendees (2.51±0.18) (p<0.01). The Korean version of CRBS has demonstrated face, content and criterion validity, suggesting it may be useful for assessing barriers to CR utilization in Korea.

MNASA as a Test for Carbon Fiber Thermal Barrier Development

NASA Technical Reports Server (NTRS)

Bauer, Paul; McCool, Alex (Technical Monitor)

2001-01-01

A carbon fiber rope thermal barrier is being evaluated as a replacement for the conventional room temperature vulcanizing (RTV) thermal barrier that is currently used to protect o-rings in Reusable Solid Rocket Motor (RSRM) nozzle joints. Performance requirements include its ability to cool any incoming, hot propellant gases that fill and pressurize the nozzle joints, filter slag and particulates, and to perform adequately in various joint assembly conditions as well as dynamic flight motion. Modified National Aeronautics and Space Administration (MNASA) motors, with their inherent and unique ability to replicate select RSRM internal environment features, were an integral step in the development path leading to full scale RSRM static test demonstration of the carbon fiber rope (CFR) joint concept. These 1/4 scale RSRM motors serve to bridge the gap between the other classes of subscale test motors (extremely small and moderate duration, or small scale and short duration) and the critical asset RSRM static test motors. A series of MNASA tests have been used to demonstrate carbon fiber rope performance and have provided rationale for implementation into a full-scale static motor and flight qualification.

Edge-induced Schottky barrier modulation at metal contacts to exfoliated molybdenum disulfide flakes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nouchi, Ryo, E-mail: r-nouchi@21c.osakafu-u.ac.jp

2016-08-14

Ultrathin two-dimensional semiconductors obtained from layered transition-metal dichalcogenides such as molybdenum disulfide (MoS{sub 2}) are promising for ultimately scaled transistors beyond Si. Although the shortening of the semiconductor channel is widely studied, the narrowing of the channel, which should also be important for scaling down the transistor, has been examined to a lesser degree thus far. In this study, the impact of narrowing on mechanically exfoliated MoS{sub 2} flakes was investigated according to the channel-width-dependent Schottky barrier heights at Cr/Au contacts. Narrower channels were found to possess a higher Schottky barrier height, which is ascribed to the edge-induced band bendingmore » in MoS{sub 2}. The higher barrier heights degrade the transistor performance as a higher electrode-contact resistance. Theoretical analyses based on Poisson's equation showed that the edge-induced effect can be alleviated by a high dopant impurity concentration, but this strategy should be limited to channel widths of roughly 0.7 μm because of the impurity-induced charge-carrier mobility degradation. Therefore, proper termination of the dangling bonds at the edges should be necessary for aggressive scaling with layered semiconductors.« less

Exploring the facilitators and barriers to engagement in physical activity for people with multiple sclerosis.

PubMed

Kayes, Nicola M; McPherson, Kathryn M; Schluter, Philip; Taylor, Denise; Leete, Marta; Kolt, Gregory S

2011-01-01

To explore the relationship that cognitive behavioural and other previously identified variables have with physical activity engagement in people with multiple sclerosis (MS). This study adopted a cross-sectional questionnaire design. Participants were 282 individuals with MS. Outcome measures included the Physical Activity Disability Survey--Revised, Cognitive and Behavioural Responses to Symptoms Questionnaire, Barriers to Health Promoting Activities for Disabled Persons Scale, Multiple Sclerosis Self-efficacy Scale, Self-Efficacy for Chronic Diseases Scales and Chalder Fatigue Questionnaire. Multivariable stepwise regression analyses found that greater self-efficacy, greater reported mental fatigue and lower number of perceived barriers to physical activity accounted for a significant proportion of variance in physical activity behaviour, over that accounted for by illness-related variables. Although fear-avoidance beliefs accounted for a significant proportion of variance in the initial analyses, its effect was explained by other factors in the final multivariable analyses. Self-efficacy, mental fatigue and perceived barriers to physical activity are potentially modifiable variables which could be incorporated into interventions designed to improve physical activity engagement. Future research should explore whether a measurement tool tailored to capture beliefs about physical activity identified by people with MS would better predict participation in physical activity.

Psychological determinants of exercise behavior of nursing students.

PubMed

Chan, Joanne Chung-Yan

2014-01-01

Though expected to be role models in health promotion, research has shown that nursing students often have suboptimal exercise behavior. This study explored the psychological factors associated with the exercise behavior of nursing students. A total of 195 first-year undergraduate nursing students completed a cross-sectional quantitative survey questionnaire, which included measures of their exercise behavior, the Physical Exercise Self-efficacy Scale, and the Exercise Barriers/Benefits Scale. The results showed that male students spent more time exercising and had higher exercise self-efficacy compared with female students, but there were no gender differences in the perceived barriers to or benefits of exercise. Fatigue brought on by exercising was the greatest perceived barrier to exercise, whereas increasing physical fitness and mental health were the greatest perceived benefits of exercise. Multiple linear regression showed that gender, exercise self-efficacy, perceived barriers to exercise, and perceived benefits of exercise were independent predictors of exercise behavior. Nurse educators can endeavor to promote exercise behavior among nursing students by highlighting the specific benefits of exercise, empowering students to overcome their perceived barriers to exercise, and enhancing students' exercise self-efficacy.

Laboratory-scale column study for remediation of TCE-contaminated aquifers using three-section controlled-release potassium permanganate barriers.

PubMed

Yuan, Baoling; Li, Fei; Chen, Yanmei; Fu, Ming-Lai

2013-05-01

A laboratory-scale study with a sand column was designed to simulate trichloroethylene (TCE) pollution in the aquifer environment with three-section controlled-release potassium permanganate (CRP) barriers. The main objective of this study was to evaluate the feasibility of CRP barriers in remediation of TCE in aquifers in a long-term and controlled manner. CRP particles with a 1:3 molar ratio of KMnO4 to stearic acid showed the best controlled-release properties in pure water, and the theoretical release time was 138.5 days. The results of TCE removal in the test column indicated that complete removal efficiency of TCE in a sand column by three-section CRP barriers could be reached within 15 days. The molar ratio of KMnO4 to TCE in the three-section CRP barriers was 16:1, which was much lower than 82:1 as required when KMnO4 solution is used directly to achieve complete destruction of TCE. This result revealed that the efficiency of CRP for remediation of TCE was highly improved after encapsulation.

Comparisons of Contraceptive Use between Rural and Urban Teens.

PubMed

Geske, Savannah; Quevillon, Randal; Struckman-Johnson, Cindy; Hansen, Keith

2016-02-01

The purpose of the study was to determine if barriers in rural areas might decrease an adolescent's likelihood of obtaining effective contraception. Previous studies have reported mixed results in comparisons of rural and urban contraception use. Electronic survey. Midwestern Public University. Undergraduate and graduate women. Questionnaire. Participants retrospectively recalled their contraceptive use and barriers to contraceptive use between the 9th and 12th grades. A Barriers to Contraception Use Scale was created using exploratory factor analysis and yielded 31 questions with 1 underlying factor: barriers. Participants were identified as rural or urban using the Office of Management and Budget (OMB) definition and the participant's self-identification. Overall, rural participants endorsed more barriers to accessing contraceptives than urban participants using the OMB definition (χ(2) (2; n = 388) = 2.04; P < .05), and self-identification (χ(2) (2; n = 398) = 2.37; P < .05). However, no differences were found in contraception use according to the OMB definition, t (380) = -1.90; P = .06, or self-identification, t (380) = -2.11; P > .05. The Barriers to Contraception Use Scale total score predicted whether an individual would have a prescription for contraceptives 70.5% of the time compared to the base rate of 54.1%. Although no rural-urban differences in actual contraception use were found, rural participants reported more barriers to accessing contraception, and those who endorsed more barriers were less likely to obtain contraceptives while in high school. Pregnancy prevention programs should thus take these barriers into account when developing future interventions. Copyright © 2016 North American Society for Pediatric and Adolescent Gynecology. Published by Elsevier Inc. All rights reserved.

Nurses' knowledge and barriers regarding pain management in intensive care units.

PubMed

Wang, Hsiang-Ling; Tsai, Yun-Fang

2010-11-01

To explore nurses' knowledge and barriers regarding pain management in intensive care units. Pain is a common and treatable condition among intensive care patients. Quality care of these patients depends on the pain knowledge and pain management skills of critical care nurses. However, no single study has explored these nurses' knowledge of and perceived barriers to pain management in Taiwan. A cross-sectional study. Intensive care unit nurses (n = 370) were recruited from 16 hospitals chosen by stratified sampling across Taipei County in Taiwan. Data were collected on nurses' knowledge of pain management using the Nurses' Knowledge and Attitudes Survey-Taiwanese version, on perceived barriers to pain management using a researcher-developed scale and on background information. The overall average correct response rate for the knowledge scale was 53.4%, indicating poor knowledge of pain management. The top barrier to managing pain identified by these nurses was 'giving proper pain prescription needs doctor's approval; can't depend on me'. Knowledge of pain management was significantly and negatively related to perceived barriers to pain management. In addition, scores for knowledge and perceived barriers differed significantly by specific intensive care unit. Knowledge also differed significantly by nurses' education level, clinical competence level (nursing ladder) and hospital accreditation category. Our results indicate an urgent need to strengthen pain education by including case analysis for intensive care nurses in Taiwan. Pain education should target knowledge deficits and barriers to changing pain management approaches for Taiwanese nurses in intensive care units. © 2010 Blackwell Publishing Ltd.

Biological effect of low-head sea lamprey barriers: Designs for extensive surveys and the value of incorporating intensive process-oriented research

USGS Publications Warehouse

Hayes, D.B.; Baylis, J.R.; Carl, L.M.; Dodd, H.R.; Goldstein, J.D.; McLaughlin, R.L.; Noakes, D.L.G.; Porto, L.M.

2003-01-01

Four sampling designs for quantifying the effect of low-head sea lamprey (Petromyzon marinus) barriers on fish communities were evaluated, and the contribution of process-oriented research to the overall confidence of results obtained was discussed. The designs include: (1) sample barrier streams post-construction; (2) sample barrier and reference streams post-construction; (3) sample barrier streams pre- and post-construction; and (4) sample barrier and reference streams pre- and post-construction. In the statistical literature, the principal basis for comparison of sampling designs is generally the precision achieved by each design. In addition to precision, designs should be compared based on the interpretability of results and on the scale to which the results apply. Using data collected in a broad survey of streams with and without sea lamprey barriers, some of the tradeoffs that occur among precision, scale, and interpretability are illustrated. Although circumstances such as funding and availability of pre-construction data may limit which design can be implemented, a pre/post-construction design including barrier and reference streams provides the most meaningful information for use in barrier management decisions. Where it is not feasible to obtain pre-construction data, a design including reference streams is important to maintain the interpretability of results. Regardless of the design used, process-oriented research provides a framework for interpreting results obtained in broad surveys. As such, information from both extensive surveys and intensive process-oriented research provides the best basis for fishery management actions, and gives researchers and managers the most confidence in the conclusions reached regarding the effects of sea lamprey barriers.

Words that make pills easier to swallow: a communication typology to address practical and perceptual barriers to medication intake behavior

PubMed Central

Linn, Annemiek J; van Weert, Julia CM; Schouten, Barbara C; Smit, Edith G; van Bodegraven, Ad A; van Dijk, Liset

2012-01-01

Purpose The barriers to patients’ successful medication intake behavior could be reduced through tailored communication about these barriers. The aim of this study is therefore (1) to develop a new communication typology to address these barriers to successful medication intake behavior, and (2) to examine the relationship between the use of the typology and the reduction of the barriers to successful medication intake behavior. Patients and methods Based on a literature review, the practical and perceptual barriers to successful medication intake behavior typology (PPB-typology) was developed. The PPB-typology addresses four potential types of barriers that can be either practical (memory and daily routine barriers) or perceptual (concern and necessity barriers). The typology describes tailored communication strategies that are organized according to barriers and communication strategies that are organized according to provider and patient roles. Eighty consultations concerning first-time medication use between nurses and inflammatory bowel disease patients were videotaped. The verbal content of the consultations was analyzed using a coding system based on the PPB-typology. The Medication Understanding and Use Self-efficacy Scale and the Beliefs about Medicine Questionnaire Scale were used as indicators of patients’ barriers and correlated with PPB-related scores. Results The results showed that nurses generally did not communicate with patients according to the typology. However, when they did, fewer barriers to successful medication intake behavior were identified. A significant association was found between nurses who encouraged question-asking behavior and memory barriers (r = −0.228, P = 0.042) and between nurses who summarized information (r = −0.254, P = 0.023) or used cartoons or pictures (r = −0.249, P = 0.026) and concern barriers. Moreover, a significant relationship between patients’ emotional cues about side effects and perceived concern barriers (r = 0.244, P = 0.029) was found as well. Conclusion The PPB-typology provides communication recommendations that are designed to meet patients’ needs and assist providers in the promotion of successful medication intake behavior, and it can be a useful tool for developing effective communication skills training programs. PMID:23271896

Activation barrier scaling and crossover for noise-induced switching in micromechanical parametric oscillators.

PubMed

Chan, H B; Stambaugh, C

2007-08-10

We explore fluctuation-induced switching in parametrically driven micromechanical torsional oscillators. The oscillators possess one, two, or three stable attractors depending on the modulation frequency. Noise induces transitions between the coexisting attractors. Near the bifurcation points, the activation barriers are found to have a power law dependence on frequency detuning with critical exponents that are in agreement with predicted universal scaling relationships. At large detuning, we observe a crossover to a different power law dependence with an exponent that is device specific.

Evaluation of a permeable reactive barrier technology for use at Rocky Flats Environmental Technology Site (RFETS)

DOE Office of Scientific and Technical Information (OSTI.GOV)

DWYER,BRIAN P.

2000-01-01

Three reactive materials were evaluated at laboratory scale to identify the optimum treatment reagent for use in a Permeable Reactive Barrier Treatment System at Rocky Flats Environmental Technology Site (RFETS). The contaminants of concern (COCS) are uranium, TCE, PCE, carbon tetrachloride, americium, and vinyl chloride. The three reactive media evaluated included high carbon steel iron filings, an iron-silica alloy in the form of a foam aggregate, and a peculiar humic acid based sorbent (Humasorb from Arctech) mixed with sand. Each material was tested in the laboratory at column scale using simulated site water. All three materials showed promise for themore » 903 Mound Site however, the iron filings were determined to be the least expensive media. In order to validate the laboratory results, the iron filings were further tested at a pilot scale (field columns) using actual site water. Pilot test results were similar to laboratory results; consequently, the iron filings were chosen for the fill-scale demonstration of the reactive barrier technology. Additional design parameters including saturated hydraulic conductivity, treatment residence time, and head loss across the media were also determined and provided to the design team in support of the final design. The final design was completed by the Corps of Engineers in 1997 and the system was constructed in the summer of 1998. The treatment system began fill operation in December, 1998 and despite a few problems has been operational since. Results to date are consistent with the lab and pilot scale findings, i.e., complete removal of the contaminants of concern (COCs) prior to discharge to meet RFETS cleanup requirements. Furthermore, it is fair to say at this point in time that laboratory developed design parameters for the reactive barrier technology are sufficient for fuel scale design; however,the treatment system longevity and the long-term fate of the contaminants are questions that remain unanswered. This project along with others such as the Durango, CO and Monticello, UT reactive barriers will provide the data to determine the long-term effectiveness and return on investment (ROI) for this technology for comparison to the baseline pump and treat.« less

Perceived barriers to effective job performance among nursing assistants in long-term care.

PubMed

Parmelee, Patricia A; Laszlo, Mary C; Taylor, Jo A

2009-10-01

This research explored perceived barriers to job performance among a national sample of nursing assistants (NAs). Specific objectives were (1) to clarify which of the problems identified by previous research are most troublesome for NAs, (2) to develop a reliable quantitative measure of perceived barriers to job performance, and (3) to test construct validity of the measure vis-à-vis work-related psychological empowerment and job satisfaction. Nursing assistants attending the 2006 national conference of the National Association of Health Care Assistants completed a paper-and-pencil survey including 33 barriers to job performance and standardized measures of empowerment and job satisfaction. The barriers were also rated by a small sample of NAs at a single Georgia nursing home. Factor analysis of barriers items yielded a 30-item Nursing Assistants Barriers Scale (NABS) comprising 6 subscales: Teamwork, Exclusion, Respect, Workload, Work Stress, and New NAs. Lack of teamwork and exclusion from communication processes were rated as most problematic by both samples. The 6 NABS subscales were significantly and independently associated with empowerment and satisfaction; different barriers predicted the 2 constructs. This study is a first step toward quantitative assessment of NAs' perceptions of barriers to doing their jobs. Primary limitations are the select sample and use of a job satisfaction measure that may have artificially inflated correlations with the NABS. Nonetheless, results confirm the validity of the new scale as an operationalization of the barriers construct. The concept of barriers to job performance is a unique construct from work empowerment and satisfaction with one's job. Nursing assistants clearly differentiate various barriers, converging on workload and lack of teamwork as most problematic. Further work is needed to substantiate validity and reliability of the NABS, particularly with respect to NAs' actual job performance, intent to stay on the job versus leave, absenteeism, and turnover.

Best-worst scaling to assess the most important barriers and facilitators for the use of health technology assessment in Austria.

PubMed

Feig, Chiara; Cheung, Kei Long; Hiligsmann, Mickaël; Evers, Silvia M A A; Simon, Judit; Mayer, Susanne

2018-04-01

Although Health Technology Assessment (HTA) is increasingly used to support evidence-based decision-making in health care, several barriers and facilitators for the use of HTA have been identified. This best-worst scaling (BWS) study aims to assess the relative importance of selected barriers and facilitators of the uptake of HTA studies in Austria. A BWS object case survey was conducted among 37 experts in Austria to assess the relative importance of HTA barriers and facilitators. Hierarchical Bayes estimation was applied, with the best-worst count analysis as sensitivity analysis. Subgroup analyses were also performed on professional role and HTA experience. The most important barriers were 'lack of transparency in the decision-making process', 'fragmentation', 'absence of appropriate incentives', 'no explicit framework for decision-making process', and 'insufficient legal support'. The most important facilitators were 'transparency in the decision-making process', 'availability of relevant HTA research for policy makers', 'availability of explicit framework for decision-making process', 'sufficient legal support', and 'appropriate incentives'. This study suggests that HTA barriers and facilitators related to the context of decision makers, especially 'policy characteristics' and 'organization and resources' are the most important in Austria. A transparent and participatory decision-making process could improve the adoption of HTA evidence.

Translation, Cross-cultural Adaptation and Psychometric Validation of the Korean-Language Cardiac Rehabilitation Barriers Scale (CRBS-K)

PubMed Central

2017-01-01

Objective To perform a translation and cross-cultural adaptation of the Cardiac Rehabilitation Barriers Scale (CRBS) for use in Korea, followed by psychometric validation. The CRBS was developed to assess patients' perception of the degree to which patient, provider and health system-level barriers affect their cardiac rehabilitation (CR) participation. Methods The CRBS consists of 21 items (barriers to adherence) rated on a 5-point Likert scale. The first phase was to translate and cross-culturally adapt the CRBS to the Korean language. After back-translation, both versions were reviewed by a committee. The face validity was assessed in a sample of Korean patients (n=53) with history of acute myocardial infarction that did not participate in CR through semi-structured interviews. The second phase was to assess the construct and criterion validity of the Korean translation as well as internal reliability, through administration of the translated version in 104 patients, principle component analysis with varimax rotation and cross-referencing against CR use, respectively. Results The length, readability, and clarity of the questionnaire were rated well, demonstrating face validity. Analysis revealed a six-factor solution, demonstrating construct validity. Cronbach's alpha was greater than 0.65. Barriers rated highest included not knowing about CR and not being contacted by a program. The mean CRBS score was significantly higher among non-attendees (2.71±0.26) than CR attendees (2.51±0.18) (p<0.01). Conclusion The Korean version of CRBS has demonstrated face, content and criterion validity, suggesting it may be useful for assessing barriers to CR utilization in Korea. PMID:29201826

Barriers associated with reduced physical activity in COPD patients*

PubMed Central

Amorim, Priscila Batista; Stelmach, Rafael; Carvalho, Celso Ricardo Fernandes; Fernandes, Frederico Leon Arrabal; Carvalho-Pinto, Regina Maria; Cukier, Alberto

2014-01-01

OBJECTIVE: To evaluate the ability of COPD patients to perform activities of daily living (ADL); to identify barriers that prevent these individuals from performing ADL; and to correlate those barriers with dyspnea severity, six-minute walk test (6MWT), and an ADL limitation score. METHODS: In COPD patients and healthy, age-matched controls, the number of steps, the distance walked, and walking time were recorded with a triaxial accelerometer, for seven consecutive days. A questionnaire regarding perceived barriers and the London Chest Activity of Daily Living (LCADL) scale were used in order to identify the factors that prevent the performance of ADL. The severity of dyspnea was assessed with two scales, whereas submaximal exercise capacity was determined on the basis of the 6MWT. RESULTS: We evaluated 40 COPD patients and 40 controls. In comparison with the control values, the mean walk time was significantly shorter for COPD patients (68.5 ± 25.8 min/day vs. 105.2 ± 49.4 min/day; p < 0.001), as was the distance walked (3.9 ± 1.9 km/day vs. 6.4 ± 3.2 km/day; p < 0.001). The COPD patients also walked fewer steps/day. The most common self-reported barriers to performing ADL were lack of infrastructure, social influences, and lack of willpower. The 6MWT distance correlated with the results obtained with the accelerometer but not with the LCADL scale results. CONCLUSIONS: Patients with COPD are less active than are healthy adults of a comparable age. Physical inactivity and the barriers to performing ADL have immediate implications for clinical practice, calling for early intervention measures. PMID:25410838

An exploratory qualitative study on perceptions about mosquito bed nets in the Niger Delta: what are the barriers to sustained use?

PubMed Central

Galvin, Kathleen T; Petford, Nick; Ajose, Frances; Davies, Dai

2011-01-01

Background: The effectiveness of malaria control programs is determined by an array of complex factors, including the acceptability and sustained use of preventative measures such as the bed net. A small-scale exploratory study was conducted in several locations in the Niger Delta region, Nigeria, to discover barriers against the use of bed nets, in the context of a current drive to scale up net use in Nigeria. Methods: A qualitative approach with a convenience sample was used. One to one interviews with mostly male adult volunteers were undertaken which explored typical living and sleeping arrangements, and perceptions about and barriers against the use of the mosquito prevention bed net. Results: Several key issues emerged from the qualitative data. Bed nets were not reported as widely used in this small sample. The reasons reported for lack of use included issues of convenience, especially net set up and dismantling; potential hazard and safety concerns; issues related to typical family composition and nature of accommodation; humid weather conditions; and perceptions of cost and effectiveness. Most barriers to net use concerned issues about everyday practical living and sleeping arrangements and perceptions about comfort. Interviewees identified were aware of malaria infection risks, but several also indicated certain beliefs that were barriers to net use. Conclusions: Successful control of malaria and scale up of insecticide-treated net coverage relies on community perceptions and practice. This small study has illuminated a number of important everyday life issues, which remain barriers to sustained net use, and has clarified further questions to be considered in net design and in future research studies. The study highlights the need for further research on the human concerns that contribute to sustained use of nets or, conversely, present significant barriers to their use. PMID:21544249

Multidimensional structure of a questionnaire to assess barriers to and motivators of physical activity in recipients of solid organ transplantation.

PubMed

van Adrichem, Edwin J; Krijnen, Wim P; Dekker, Rienk; Ranchor, Adelita V; Dijkstra, Pieter U; van der Schans, Cees P

2017-11-01

To explore the underlying dimensions of the Barriers and Motivators Questionnaire that is used to assess barriers to and motivators of physical activity experienced by recipients of solid organ transplantation and thereby improve the application in research and clinical settings. A cross-sectional study was performed in recipients of solid organ transplantation (n = 591; median (IQR) age = 59 (49; 66); 56% male). The multidimensional structure of the questionnaire was analyzed by exploratory principal component analysis. Cronbach's α was calculated to determine internal consistency of the entire questionnaire and individual components. The barriers scale had a Cronbach's α of 0.86 and was subdivided into four components; α of the corresponding subscales varied between 0.80 and 0.66. The motivator scale had an α of 0.91 and was subdivided into four components with an α between 0.88 to 0.70. Nine of the original barrier items and two motivator items were not included in the component structure. A four-dimensional structure for both the barriers and motivators scale of the questionnaire is supported. The use of the indicated subscales increases the usability in research and clinical settings compared to the overall scores and provide opportunities to identify modifiable constructs to be targeted in interventions. Implications for rehabilitation Organ transplant recipients are less active than the general population despite established health benefits of physical activity. A multidimensional structure is shown in the Barriers and Motivators Questionnaire, the use of the identified subscales increases applicability in research and clinical settings. The use of the questionnaire with its component structure in the clinical practice of a rehabilitation physician could result in a faster assessment of problem areas in daily practice and result in a higher degree of clarity as opposed to the use of the individual items of the questionnaire.

Transgressive Shoreface Response in the Mississippi River DeltaShoreface Sediment Budget Influence on Barrier Island Evolution, Louisiana, USA

NASA Astrophysics Data System (ADS)

Beasley, B.; Georgiou, I. Y.; Miner, M. D.

2017-12-01

In Louisiana barrier islands are undergoing rapid morphological change due to shoreface retreat and increasing bay tidal prism driven by high rates of relative sea-level rise (RSLR) (1 cm/yr) and interior wetland loss, respectively. Previous works utilized historical region-scale bathymetry change and shoreline change analyses to assess large-scale coastal evolution. However, more localized assessments considering the role of sediment transport processes in regional evolution are lacking. This is essential to predicting coastal change trajectories and allocating limited sand resources for nourishment. Using historic bathymetric and shoreline data dating to the 1890s for the Louisiana coast, 100-m spaced shore-normal transects were created to track meter-scale elevation change for 1890, 1930, 1980, 2006, and 2015. An automated framework was used to quantify and track barrier island evolution parameters such as shoreline change, area, width, bathymetric contour migration, and shoreface slope. During the 125 yr analysis period, shoreline erosion mean rates slowed from 12 to 6 m/yr while lower shoreface migration mean rates increased from 5 to 25 m/yr. Locally, retreat rates for the Caminada Headland upper shoreface slowed from 18 to 8 m/yr while lower shoreface retreat rates increased from 8 to 14m/yr. The Timbalier Islands experienced increased migration rates along the entire shoreface, while the lower shoreface of the Isles Dernieres transitioned from progradational to erosional (-5 m/yr in 1890 to 20 m/yr in 2006). Our analysis suggests that although shoreline erosion rates decreased, overall landward migration of the barrier system increased as the shoreface steepened. Our results illustrate that monitoring subaerial island erosion rates are insufficient for evaluating regional dynamics of transgressive coastal systems. The longevity of barriers appears diminished due to a reduction in the shoreface sediment available and further corroborates the role of the shoreface on barrier island evolution. Advances in understanding these processes will facilitate more informed planning, management, and mitigation of transgressive barrier islands.

APPLICATION OF THE PERMEABLE REACTIVE BARRIER TECHNOLOGY FOR THE TREATMENT OF ARSENIC IN GROUND WATER

EPA Science Inventory

The research approach will involve hydrogeological and geochemical studies to provide information needed in order to select an appropriate design configuration and to evaluate the performance of a pilot-scale subsurface permeable reactive barrier to remediate arsenic-contaminated...

Condensation on superhydrophobic surfaces: the role of local energy barriers and structure length scale.

PubMed

Enright, Ryan; Miljkovic, Nenad; Al-Obeidi, Ahmed; Thompson, Carl V; Wang, Evelyn N

2012-10-09

Water condensation on surfaces is a ubiquitous phase-change process that plays a crucial role in nature and across a range of industrial applications, including energy production, desalination, and environmental control. Nanotechnology has created opportunities to manipulate this process through the precise control of surface structure and chemistry, thus enabling the biomimicry of natural surfaces, such as the leaves of certain plant species, to realize superhydrophobic condensation. However, this "bottom-up" wetting process is inadequately described using typical global thermodynamic analyses and remains poorly understood. In this work, we elucidate, through imaging experiments on surfaces with structure length scales ranging from 100 nm to 10 μm and wetting physics, how local energy barriers are essential to understand non-equilibrium condensed droplet morphologies and demonstrate that overcoming these barriers via nucleation-mediated droplet-droplet interactions leads to the emergence of wetting states not predicted by scale-invariant global thermodynamic analysis. This mechanistic understanding offers insight into the role of surface-structure length scale, provides a quantitative basis for designing surfaces optimized for condensation in engineered systems, and promises insight into ice formation on surfaces that initiates with the condensation of subcooled water.

Transforming a Liability Into An Asset-Creating a Market for CO2-based Products

NASA Astrophysics Data System (ADS)

David, B. J.

2016-12-01

This session will discuss converting CO2 from a liability into an asset. It will specifically discuss how at least 25 products can be created using CO2 as a feedstock and deployed in the market at large scale. Focus will be on products that can both achieve scale from a market standpoint as well as climate significance in use of CO2 as a feedstock. The session will describe the market drivers supporting and inhibiting commercial deployment of CO2-based products. It will list key barriers and risks in the various CO2-based product segments. These barriers/risks could occur across technology, policy, institutional, economic, and other dimensions. The means to mitigate each barrier and the likelihood for such means to be deployed will be discussed.

Drivers and barriers to e-invoicing adoption in Greek large scale manufacturing industries

NASA Astrophysics Data System (ADS)

Marinagi, Catherine; Trivellas, Panagiotis; Reklitis, Panagiotis; Skourlas, Christos

2015-02-01

This paper attempts to investigate the drivers and barriers that large-scale Greek manufacturing industries experience in adopting electronic invoices (e-invoices), based on three case studies with organizations having international presence in many countries. The study focuses on the drivers that may affect the increase of the adoption and use of e-invoicing, including the customers demand for e-invoices, and sufficient know-how and adoption of e-invoicing in organizations. In addition, the study reveals important barriers that prevent the expansion of e-invoicing, such as suppliers' reluctance to implement e-invoicing, and IT infrastructures incompatibilities. Other issues examined by this study include the observed benefits from e-invoicing implementation, and the financial priorities of the organizations assumed to be supported by e-invoicing.

Scale-dependent behavior of the foredune: Implications for barrier island response to storms and sea-level rise

NASA Astrophysics Data System (ADS)

Houser, Chris; Wernette, Phil; Weymer, Bradley A.

2018-02-01

The impact of storm surge on a barrier island tends to be considered from a single cross-shore dimension, dependent on the relative elevations of the storm surge and dune crest. However, the foredune is rarely uniform and can exhibit considerable variation in height and width at a range of length scales. In this study, LiDAR data from barrier islands in Texas and Florida are used to explore how shoreline position and dune morphology vary alongshore, and to determine how this variability is altered or reinforced by storms and post-storm recovery. Wavelet analysis reveals that a power law can approximate historical shoreline change across all scales, but that storm-scale shoreline change ( 10 years) and dune height exhibit similar scale-dependent variations at swash and surf zone scales (< 1000 m). The in-phase nature of the relationship between dune height and storm-scale shoreline change indicates that areas of greater storm-scale shoreline retreat are associated with areas of smaller dunes. It is argued that the decoupling of storm-scale and historical shoreline change at swash and surf zone scales is also associated with the alongshore redistribution of sediment and the tendency of shorelines to evolve to a more diffusive (or straight) pattern with time. The wavelet analysis of the data for post-storm dune recovery is also characterized by red noise at the smallest scales characteristic of diffusive systems, suggesting that it is possible that small-scale variations in dune height can be repaired through alongshore recovery and expansion if there is sufficient time between storms. However, the time required for dune recovery exceeds the time between storms capable of eroding and overwashing the dune. Correlation between historical shoreline retreat and the variance of the dune at swash and surf zone scales suggests that the persistence of the dune is an important control on transgression through island migration or shoreline retreat with relative sea-level rise.

Tunable Nitride Josephson Junctions.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Missert, Nancy A.; Henry, Michael David; Lewis, Rupert M.

We have developed an ambient temperature, SiO 2/Si wafer - scale process for Josephson junctions based on Nb electrodes and Ta x N barriers with tunable electronic properties. The films are fabricated by magnetron sputtering. The electronic properties of the Ta xN barriers are controlled by adjusting the nitrogen flow during sputtering. This technology offers a scalable alternative to the more traditional junctions based on AlO x barriers for low - power, high - performance computing.

Small Barriers Trigger Liftoff of Unconfined Dilute Heated Laboratory Density Currents

NASA Astrophysics Data System (ADS)

Fauria, K.; Andrews, B. J.; Manga, M.

2015-12-01

Dilute pyroclastic density currents (PDCs) are hot, turbulent, particle-laden flows that propagate because they are denser than air. PDCs can traverse tens to hundreds of kilometers and surmount ridges 100s of m tall, yet the effects of complex topography on PDC liftoff and runout distance are uncertain. Here we used scaled laboratory experiments to explore how barriers affect dilute density current dynamics and the occurrence of liftoff. We created dilute density currents by heating and suspending 20 μm diameter talc in air in an 8.5 x 6.1 x 2.6 m tank. We scaled the currents with respect to Froude, densimetric and thermal Richardson, particle Stokes and Settling numbers such that they were dynamically similar to natural PDCs. While currents were fully turbulent, their Reynolds numbers were not as high as those for natural PDCs. We performed the first set of experiments in a laterally unconfined volume, used laser sheets to illuminate the currents, measured bulk sedimentation rates down the current centerlines, and positioned four to twenty-four cm tall ridge-like barriers in the path of the currents. We found that relatively small barriers (~ half the current height) caused PDC liftoff. By comparison, conservation of kinetic and potential energy predicts that incompressible density currents are able to surmount barriers twice their height. Furthermore, we observed increased sedimentation immediately upstream of barriers and conclude that small barriers initiated buoyancy reversal through a combination of increased air entrainment and sedimentation. We conducted a second set of experiments with the same thermal scaling and mass flux rates but where the currents were laterally confined within a 0.6 m wide channel. We found that small barriers also triggered liftoff of confined currents, but that the body of these currents reattached after liftoff. Those results suggest that lateral confinement inhibits buoyancy reversal by limiting the surface area of the current-air interface and air entrainment. Real dilute PDCs that originate in confined valleys may therefore have different fates and longer runout distances than those on unconfined planes.

Microstructural investigation of current barriers in high temperature superconducting tapes and coated conductors

NASA Astrophysics Data System (ADS)

Reeves, Jodi Lynn

Microstructural barriers to supercurrent occur on many length scales in all high temperature oxide superconductors. Eliminating microstructural barriers is key to making these potentially valuable materials more favorable for commercial applications. In silver-sheathed Bi2Sr2CaCu 2Ox (Bi-2212) tapes and multifilaments, the principal barriers on the scale of 10--100's of micrometers are bubbling, porosity, second phase particles, and poorly aligned grains. In state-of-the-art YBa2 Cu3Ox (YBCO) coated conductors, supercurrent barriers on the 0.1--100mum scale are grain boundaries. This thesis work clarifies the role of grain boundaries in the nickel substrate of RABiTS (Rolling Assisted Biaxially Textured Substrate) coated conductors. Plan-view SEM imaging, focused ion beam cutting, magneto-optical imaging and grain orientation mapping were used to determine barriers to supercurrent. Experiments showed enhanced magnetic flux penetration, and hence reduced Jc, in the YBCO above nearly all nickel grain boundaries with misorientation angles (theta) greater than 5°, independent of the rotation axis. Monochromatic backscattered electron Kikuchi pattern percolation maps imply there is a fully connected current path through the YBCO microstructure within the chosen tolerance angle criterion of the map. However, it is the grain boundary map that displays the constrictions of the current path. Therefore, grain boundary maps are better tools for illustrating supercurrent barriers than percolation maps. Grain boundary maps and grain orientation maps were used to investigate how the texture of the substrate was transferred to the buffer layers and to the superconductor. Most grasp boundaries in the nickel were replicated in the buffer and superconductor layers with the same misorientation angle. Anisotropic growth and/or surface energy minimization may be responsible for the improvement in c-axis alignment in the YBCO over the buffer layer. However, the YBCO mosaic spread did not eliminate high angle grain boundaries, since >5° boundaries were still seen in YBCO grain boundary maps. The results of this study on microstructural current barriers show that Jc improvements in RABiTS-type coated conductors require eliminating theta > 5° boundaries in the nickel substrate.

Controlled growth of aligned carbon nanotube using pulsed glow barrier discharge

NASA Astrophysics Data System (ADS)

Nozaki, Tomohiro; Kimura, Yoshihito; Okazaki, Ken

2002-10-01

We first achieved a catalytic growth of aligned carbon nanotube (CNT) using atmospheric pressure pulsed glow barrier discharge combined with DC bias (1000 V). Aligned CNT can grow with the directional electric field, and this is a big challenge in barrier discharges since dielectric barrier does not allow DC bias and forces to use AC voltage to maintain stable plasma conditions. To overcome this, we developed a power source generating Gaussian-shape pulses at 20 kpps with 4% duty, and DC bias was applied to the GND electrode where Ni-, Fe-coated substrate existed. With positive pulse, i.e. substrate was the cathode, random growth of CNT was observed at about 10^9 cm-2. Growth rate significantly reduced when applied negative pulse; Negative glow formation near substrate is essential for sufficient supply of radical species to the catalyst. If -DC was biased, aligned CNT with 20 nm was synthesized because negative bias enhanced negative glow formation. Interestingly, 2 to 3 CNTs stuck each other with +DC bias, resulting in 50-70 nm and non-aligned CNT. Atmospheric pressure glow barrier discharges can be highly controlled and be a potential alternative to vacuum plasmas for CVD, micro-scale, nano-scale fabrication.

AMELIORATION OF ACID MINE DRAINAGE USING REACTIVE MIXTURES IN PERMEABLE REACTIVE BARRIERS

EPA Science Inventory

The generation and release of acidic drainage from mine wastes is an environmental problem of international scale. The use of zero-valent iron and/or iron mixtures in subsurface Permeable Reactive Barriers (PRB) presents a possible passive alternative for remediating acidic grou...

Magnetized advective accretion flows: formation of magnetic barriers in magnetically arrested discs

NASA Astrophysics Data System (ADS)

Mondal, Tushar; Mukhopadhyay, Banibrata

2018-05-01

We discuss the importance of large-scale strong magnetic field in the removal of angular momentum outward, as well as the possible origin of different kinds of magnetic barrier in advective, geometrically thick, sub-Keplerian accretion flows around black holes. The origin of this large-scale strong magnetic field near the event horizon is due to the advection of the magnetic flux by the accreting gas from the environment, say, the interstellar medium or a companion star, because of flux freezing. In this simplest vertically averaged, 1.5-dimensional disc model, we choose the maximum upper limit of the magnetic field, which the disc around a black hole can sustain. In this so called magnetically arrested disc model, the accreting gas either decelerates or faces the magnetic barrier near the event horizon by the accumulated magnetic field depending on the geometry. The magnetic barrier may knock the matter to infinity. We suggest that these types of flow are the building block to produce jets and outflows in the accreting system. We also find that in some cases, when matter is trying to go back to infinity after knocking the barrier, matter is prevented being escaped by the cumulative action of strong gravity and the magnetic tension, hence by another barrier. In this way, magnetic field can lock the matter in between these two barriers and it might be a possible explanation for the formation of episodic jet.

All high Tc edge-geometry weak links utilizing Y-Ba-Cu-O barrier layers

NASA Technical Reports Server (NTRS)

Hunt, B. D.; Foote, M. C.; Bajuk, L. J.

1991-01-01

High quality YBa2Cu3O(7-x) normal-metal/YBa2Cu3O(7-x) edge-geometry weak links have been fabricated using nonsuperconducting Y-Ba-Cu-O barrier layers deposited by laser ablation at reduced growth temperatures. Devices incorporating 25-100 A thick barrier layers exhibit current-voltage characteristics consistent with the resistively shunted junction model, with strong microwave and magnetic field response at temperatures up to 85 K. The critical currents vary exponentially with barrier thickness, and the resistances scale linearly with Y-Ba-Cu-O interlayer thickness and device area, indicating good barrier uniformity, with an effective mormal metal coherence length of 20 A.

Resonances for Symmetric Two-Barrier Potentials

ERIC Educational Resources Information Center

Fernandez, Francisco M.

2011-01-01

We describe a method for the accurate calculation of bound-state and resonance energies for one-dimensional potentials. We calculate the shape resonances for symmetric two-barrier potentials and compare them with those coming from the Siegert approximation, the complex scaling method and the box-stabilization method. A comparison of the…

Test matrices for evaluating cable median barriers placed in v-ditches.

DOT National Transportation Integrated Search

2012-07-01

Cable barrier systems designed to be used in median ditches have been traditionally full-scale crash tested placed either : within 4 ft from the slope break point (SBP) of a 4H:1V front slope or near the bottom of the ditch. Recently, there has been ...

CHROMIUM REMOVAL PROCESSES DURING GROUNDWATER REMEDIATION BY A ZEROVALENT IRON PERMEABLE REACTIVE BARRIER

EPA Science Inventory

Solid-phase associations of chromium were examined in core materials collected from a full-scale, zerovalent iron, permeable reactive barrier (PRB) at the U.S. Coast Guard Support Center located near Elizabeth City (NC). The PRB was installed in 1996 to treat groundwater contami...

Noise control for rapid transit cars on elevated structures : preliminary investigation of vehicle skirts, undercar absorption, and noise barriers

DOT National Transportation Integrated Search

1980-04-01

In the report, procedures to reduce the propulsion system noise of urban rail transit vehicles on elevated structures are studied. Experiments in a laboratory use a scale model transit vehicle to evaluate the acoustical effectiveness of noise barrier...

From coastal barriers to mountain belts - commonalities in fundamental geomorphic scaling laws

NASA Astrophysics Data System (ADS)

Lazarus, E.

2016-12-01

Overwash is a sediment-transport process essential to the form and resilience of coastal barrier landscapes. Driven by storm events, overwash leaves behind distinctive sedimentary features that, although intensively studied, have lacked unifying quantitative descriptions with which to compare their morphological attributes across documented examples or relate them to other morphodynamic phenomena. Geomorphic scaling laws quantify how measures of shape and size change with respect to another - information that helps to constrain predictions of future change and reconstructions of past environmental conditions. Here, a physical model of erosional and depositional overwash morphology yields intrinsic, allometric scaling laws involving length, width, area, volume, and alongshore spacing. Corroborative comparisons with natural washover morphology indicate scale invariance spanning several orders of magnitude. Several observers of the physical model remarked that the overwashed barrier resembled a dissected linear mountain front with an alluvial apron - an intriguing reimagining of the intended analog. Indeed, that resemblance is reflected quantitatively in these new scaling relationships, which align with canonical scaling laws for terrestrial and marine drainage basins and alluvial fans on Earth and Mars. This finding suggests disparate geomorphic systems that share common allometric properties may be related dynamically, perhaps by an influence more fundamental than characteristic erosion and deposition processes. Such an influence could come from emergent behavior at the intersection of advection and diffusion. Geomorphic behaviors at advection-diffusion transitions (and vice versa), specifically, could be the key to disentangling mechanistic causality from acausality in physical landscape patterns.

Knowledge, attitude and perceptions of breast cancer screening among native and immigrant women in Barcelona, Spain.

PubMed

Pons-Vigués, Mariona; Puigpinós-Riera, Rosa; Serral, Gemma; Pasarín, M Isabel; Rodríguez, Dolors; Pérez, Glòria; Benet, Josep; Casamitjana, Montserrat; Borrell, Carme

2012-06-01

Inequalities between immigrant and native populations in terms of access and use of health services have been described. The objective is to compare knowledge, attitudes, vulnerabilities, benefits and barriers related to breast cancer (BC) and screening mammography among women from different countries resident in Barcelona. A cross-sectional survey carried out in Barcelona in 2009. The study population consisted of female residents in Barcelona between 45 and 69 years of age; participants were Spanish nationals or immigrants from low-income countries. 960 participants were asked 72 questions, mainly with Likert responses. The dependent variables were five quantitative scales: (1) knowledge of BC and early detection, (2) attitude towards health and BC, (3) vulnerability to BC, (4) barriers to mammography, (5) benefits of mammography. The independent variables were country of origin, social class, setting, cohabitation, age, mammography use, length of residence and fluency of the language. Analyses compared scale scores stratified by the independent variables. Multivariable linear regression models were fitted to determine the relationship between the scales and the independent variables. We observed inequalities according to country of origin on all scales after adjustment for independent variables. Chinese women presented the greatest differences with respect to native women, followed by Maghrebi and Filipino women. Inequalities exist on the vulnerability and barriers scales according to social class and urban/rural setting, and on the attitude scale according to social class. Country of origin, social class and urban/rural setting are key contributors to inequality in these scales. Copyright © 2011 John Wiley & Sons, Ltd.

Global report on preterm birth and stillbirth (4 of 7): delivery of interventions

PubMed Central

2010-01-01

Background The efficacious interventions identified in the previous article of this report will fail unless they are delivered at high and equitable coverage. This article discusses critical delivery constraints and strategies. Barriers to scaling up interventions Achieving universal coverage entails addressing major barriers at many levels. An overarching constraint is the lack of political will, resulting from the dearth of preterm birth and stillbirth data and the lack of visibility. Other barriers exist at the household and community levels, such as insufficient demand for interventions or sociocultural barriers; at the health services level, such as a lack of resources and trained healthcare providers; and at the health sector policy and management level, such as poorly functioning, centralized systems. Additional constraints involve weak governance and accountability, political instability, and challenges in the physical environment. Strategies and examples Scaling up maternal, newborn and child health interventions requires strengthening health systems, but there is also a role for focused, targeted interventions. Choosing a strategy involves identifying appropriate channels for reaching high coverage, which depends on many factors such as access to and attendance at healthcare facilities. Delivery channels vary, and may include facility- and community-based healthcare providers, mass media campaigns, and community-based approaches and marketing strategies. Issues related to scaling up are discussed in the context of four interventions that may be given to mothers at different stages throughout pregnancy or to newborns: (1) detection and treatment of syphilis; (2) emergency Cesarean section; (3) newborn resuscitation; and (4) kangaroo mother care. Systematic reviews of the literature and large-scale implementation studies are analyzed for each intervention. Conclusion Equitable and successful scale-up of preterm birth and stillbirth interventions will require addressing multiple barriers, and utilizing multiple delivery approaches and channels. Another important need is developing strategies to discontinue ineffective or harmful interventions. Preterm birth and stillbirth interventions must also be placed in the broader maternal, newborn and child health context to identify and prioritize those that will help improve several outcomes at the same time. The next article discusses advocacy challenges and opportunities. PMID:20233385

A new scale for disaster nursing core competencies: Development and psychometric testing.

PubMed

Al Thobaity, Abdulellah; Williams, Brett; Plummer, Virginia

2016-02-01

All nurses must have core competencies in preparing for, responding to and recovering from a disaster. In the Kingdom of Saudi Arabia (KSA), as in many other countries, disaster nursing core competencies are not fully understood and lack reliable, validated tools. Thus, it is imperative to develop a scale for exploring disaster nursing core competencies, roles and barriers in the KSA. This study's objective is to develop a valid, reliable scale that identifies and explores core competencies of disaster nursing, nurses' roles in disaster management and barriers to developing disaster nursing in the KSA. This study developed a new scale testing its validity and reliability. A principal component analysis (PCA) was used to develop and test psychometric properties of the new scale. The PCA used a purposive sample of nurses from emergency departments in two hospitals in the KSA. Participants rated 93 paper-based, self-report questionnaire items from 1 to 10 on a Likert scale. PCA using Varimax rotation was conducted to explore factors emerging from responses. The study's participants were 132 nurses (66% response rate). PCA of the 93 questionnaire items revealed 49 redundant items (which were deleted) and 3 factors with eigenvalues of >1. The remaining 44 items accounted for 77.3% of the total variance. The overall Cronbach's alpha was 0.96 for all factors: 0.98 for Factor 1, 0.92 for Factor 2 and 0.86 for Factor 3. This study provided a validated, reliable scale for exploring nurses' core competencies, nurses' roles and barriers to developing disaster nursing in the KSA. The new scale has many implications, such as for improving education, planning and curricula. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

Wave-induced coherent turbulence structures and sediment resuspension in the nearshore of a prototype-scale sandy barrier beach

NASA Astrophysics Data System (ADS)

Kassem, Hachem; Thompson, Charlotte E. L.; Amos, Carl L.; Townend, Ian H.

2015-10-01

The suspension of sediments by oscillatory flows is a complex case of fluid-particle interaction. The aim of this study is to provide insight into the spatial (time) and scale (frequency) relationships between wave-generated boundary layer turbulence and event-driven sediment transport beneath irregular shoaling and breaking waves in the nearshore of a prototype sandy barrier beach, using data collected through the Barrier Dynamics Experiment II (BARDEX II). Statistical, quadrant and spectral analyses reveal the anisotropic and intermittent nature of Reynolds' stresses (momentum exchange) in the wave boundary layer, in all three orthogonal planes of motion. The fractional contribution of coherent turbulence structures appears to be dictated by the structural form of eddies beneath plunging and spilling breakers, which in turn define the net sediment mobilisation towards or away from the barrier, and hence ensuing erosion and accretion trends. A standing transverse wave is also observed in the flume, contributing to the substantial skewness of spanwise turbulence. Observed low frequency suspensions are closely linked to the mean flow (wave) properties. Wavelet analysis reveals that the entrainment and maintenance of sediment in suspension through a cluster of bursting sequence is associated with the passage of intermittent slowly-evolving large structures, which can modulate the frequency of smaller motions. Outside the boundary layer, small scale, higher frequency turbulence drives the suspension. The extent to which these spatially varied perturbation clusters persist is associated with suspension events in the high frequency scales, decaying as the turbulent motion ceases to supply momentum, with an observed hysteresis effect.

Drivers and barriers to e-invoicing adoption in Greek large scale manufacturing industries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marinagi, Catherine, E-mail: marinagi@teihal.gr, E-mail: ptrivel@yahoo.com, E-mail: preklitis@yahoo.com; Trivellas, Panagiotis, E-mail: marinagi@teihal.gr, E-mail: ptrivel@yahoo.com, E-mail: preklitis@yahoo.com; Reklitis, Panagiotis, E-mail: marinagi@teihal.gr, E-mail: ptrivel@yahoo.com, E-mail: preklitis@yahoo.com

2015-02-09

This paper attempts to investigate the drivers and barriers that large-scale Greek manufacturing industries experience in adopting electronic invoices (e-invoices), based on three case studies with organizations having international presence in many countries. The study focuses on the drivers that may affect the increase of the adoption and use of e-invoicing, including the customers demand for e-invoices, and sufficient know-how and adoption of e-invoicing in organizations. In addition, the study reveals important barriers that prevent the expansion of e-invoicing, such as suppliers’ reluctance to implement e-invoicing, and IT infrastructures incompatibilities. Other issues examined by this study include the observed benefitsmore » from e-invoicing implementation, and the financial priorities of the organizations assumed to be supported by e-invoicing.« less

Validating the Modified Drug Adherence Work-Up (M-DRAW) Tool to Identify and Address Barriers to Medication Adherence.

PubMed

Lee, Sun; Bae, Yuna H; Worley, Marcia; Law, Anandi

2017-09-08

Barriers to medication adherence stem from multiple factors. An effective and convenient tool is needed to identify these barriers so that clinicians can provide a tailored, patient-centered consultation with patients. The Modified Drug Adherence Work-up Tool (M-DRAW) was developed as a 13-item checklist questionnaire to identify barriers to medication adherence. The response scale was a 4-point Likert scale of frequency of occurrence (1 = never to 4 = often). The checklist was accompanied by a GUIDE that provided corresponding motivational interview-based intervention strategies for each identified barrier. The current pilot study examined the psychometric properties of the M-DRAW checklist (reliability, responsiveness and discriminant validity) in patients taking one or more prescription medication(s) for chronic conditions. A cross-sectional sample of 26 patients was recruited between December 2015 and March 2016 at an academic medical center pharmacy in Southern California. A priming question that assessed self-reported adherence was used to separate participants into the control group of 17 "adherers" (65.4%), and into the intervention group of nine "unintentional and intentional non-adherers" (34.6%). Comparable baseline characteristics were observed between the two groups. The M-DRAW checklist showed acceptable reliability (13 item; alpha = 0.74) for identifying factors and barriers leading to medication non-adherence. Discriminant validity of the tool and the priming question was established by the four-fold number of barriers to adherence identified within the self-selected intervention group compared to the control group (4.4 versus 1.2 barriers, p < 0.05). The current study did not investigate construct validity due to small sample size and challenges on follow-up with patients. Future testing of the tool will include construct validation.

Music therapists' research activity and utilization barriers: a survey of the membership.

PubMed

Waldon, Eric G

2015-01-01

Music therapists have access to a rapidly expanding body of research supporting the use of music-based interventions. What is not known is the extent to which music therapists access these resources and what factors may prevent them from incorporating research findings into clinical work. After constructing the Music Therapists' Research Activity and Utilization Barrier (MTRAUB) database, the purposes of this study involved: assessing the extent to which American Music Therapy Association (AMTA) members engage in certain research-related activities; and identifying respondents' perceived barriers to integrating research into clinical practice. This study employed a quantitative, non-experimental approach using an online survey. Respondents included professional, associate, student/graduate student, retired, inactive, and honorary life members of AMTA. Instrumentation involved a researcher-designed Background Questionnaire as well as the Barriers to Research Utilization Scale (BARRIERS; Funk, Champagne, Wiese, & Tornquist, 1991), a tool designed to assess perceived barriers to incorporating research into practice. Of the 3,194 survey invitations distributed, 974 AMTA members replied (a response rate of 30%). Regarding research-related activities, descriptive findings indicate that journal reading is the most frequently reported research-related activity while conducting research is the least frequently reported activity. Results from the BARRIERS Scale indicated that Organizational and Communication factors are perceived as interfering most prominently with the ability to utilize research in clinical practice. Findings suggest that research-related activity and perceived barriers vary as a function of educational attainment, work setting, and occupational role. The author discusses these differential findings in detail, suggests supportive mechanisms to encourage increased research activity and utilization, and offers recommendations for further analysis of the MTRAUB data. © the American Music Therapy Association 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Unpacking the 'information barrier': comparing perspectives on information as a barrier to climate change adaptation in the interior mountain West.

PubMed

Archie, Kelli M; Dilling, Lisa; Milford, Jana B; Pampel, Fred C

2014-01-15

Inadequate information has been repeatedly identified as a barrier to climate change adaptation planning and implementation. However less is known about how information functions as a barrier, and to what degree it prevents adaptation compared to other perceived barriers. In addition, the role of institutional context in mediating the demand for information in the context of adaptation has been less well studied. This paper helps to clarify the role that information plays in adaptation planning for two sectors of public employees working at similar scales, in similar locations, with similar challenges. We conducted surveys and semi-structured interviews to investigate the demand for information in support of adaptation implementation and planning from US federal public lands managers and municipal officials in the US interior West. We found that federal managers and municipal officials both consulted information frequently for decision making, and while both groups indicated that lack of information at relevant scales was a barrier to adaptation planning, this was seen as a much stronger barrier for federal managers than for communities. Uncertainty of information was raised as an issue, but results were mixed on whether or not this acted as a strong barrier. While peer-reviewed publications were seen as the "best available science," and correlated with adaptation planning, they were not accessed directly as frequently as other sources of information, including colleagues, the internet and reports. The strong connection between communities and adjacent federal lands may provide an opportunity for networking that could facilitate the flow of information relevant for adaptation. Copyright © 2013 Elsevier Ltd. All rights reserved.

Recent developments in large-scale ozone generation with dielectric barrier discharges

NASA Astrophysics Data System (ADS)

Lopez, Jose L.

2014-10-01

Large-scale ozone generation for industrial applications has been entirely based on the creation of microplasmas or microdischarges created using dielectric barrier discharge (DBD) reactors. Although versions of DBD generated ozone have been in continuous use for over a hundred years especially in water treatment, recent changes in environmental awareness and sustainability have lead to a surge of ozone generating facilities throughout the world. As a result of this enhanced global usage of this environmental cleaning application various new discoveries have emerged in the science and technology of ozone generation. This presentation will describe some of the most recent breakthrough developments in large-scale ozone generation while further addressing some of the current scientific and engineering challenges of this technology.

Barriers to accessing and using contraception in highland Guatemala: the development of a family planning self-efficacy scale

PubMed Central

Richardson, Emma; Allison, Kenneth R; Gesink, Dionne; Berry, Albert

2016-01-01

Understanding the persistent inequalities in the prevalence rates of family planning and unmet need for family planning between indigenous and nonindigenous women in Guatemala requires localized explorations of the specific barriers faced by indigenous women. Based on social cognitive theory, elicitation interviews were carried out with a purposive sample of 16 young women, aged 20–24 years, married or in union, from the rural districts of Patzún, Chimaltenango, Guatemala. Content analysis was carried out using the constant-comparison method to identify the major themes. Based on this qualitative study, the following barriers are incorporated into the development of a self-efficacy scale: lack of knowledge about and availability of methods, fear of side effects and infertility, husbands being against family planning (and related fears of marital problems and abandonment), pressure from in-laws and the community, and the belief that using contraception is a sin. This is the first evidence-informed self-efficacy scale developed with young adult, indigenous women that addresses the issue of family planning in Latin America. PMID:29386939

Barriers to physical activity among working mothers.

PubMed

Dombrowski, Jill J

2011-04-01

Working mothers experience several barriers to physical activity. If these barriers can be identified by occupational health nurses and they can partner with working mothers to reduce these perceived barriers, the health of these workers can be improved and chronic disease risk prevented. The purpose of this study was to measure the effect of self-regulatory efficacy on physical activity among working mothers and to describe specific barriers to physical activity. The Barriers Specific Self-Efficacy Scale (BARSE) and the Kaiser Physical Activity Survey (KPAS) were used to measure the variables. Self-regulatory efficacy was found to be a strong predictor of physical activity in a diverse sample of working mothers who did not meet current recommendations for physical activity. Occupational health nurses can use these findings to design programs for groups and for counseling individuals. Copyright 2011, SLACK Incorporated.

Development of a continuous motorcycle protection barrier system using computer simulation and full-scale crash testing.

PubMed

Atahan, Ali O; Hiekmann, J Marten; Himpe, Jeffrey; Marra, Joseph

2018-07-01

Road restraint systems are designed to minimize the undesirable effects of roadside accidents and improve safety of road users. These systems are utilized at either side or median section of roads to contain and redirect errant vehicles. Although restraint systems are mainly designed against car, truck and bus impacts there is an increasing pressure by the motorcycle industry to incorporate motorcycle protection systems into these systems. In this paper development details of a new and versatile motorcycle barrier, CMPS, coupled with an existing vehicle barrier is presented. CMPS is intended to safely contain and redirect motorcyclists during a collision event. First, crash performance of CMPS design is evaluated by means of a three dimensional computer simulation program LS-DYNA. Then full-scale crash tests are used to verify the acceptability of CMPS design. Crash tests were performed at CSI proving ground facility using a motorcycle dummy in accordance with prEN 1317-8 specification. Full-scale crash test results show that CMPS is able to successfully contain and redirect dummy with minimal injury risk on the dummy. Damage on the barrier is also minimal proving the robustness of the CMPS design. Based on the test findings and further review by the authorities the implementation of CMPS was recommended at highway system. Copyright © 2017 Elsevier Ltd. All rights reserved.

Development of the Motivators of and Barriers to Health-Smart Behaviors Inventory.

PubMed

Tucker, Carolyn M; Rice, Kenneth G; Hou, Wei; Kaye, Lillian B; Nolan, Sarah E M; Grandoit, Delphia J; Gonzales, Lucia; Smith, Mary B; Desmond, Frederic F

2011-06-01

The Motivators of and Barriers to Health-Smart Behaviors Inventory (MB-HSBI) was developed for use in identifying self-reported motivators of and barriers to the following health-promoting behaviors (called health-smart behaviors) that should occur daily to help promote health and overcome illnesses/diseases: eating a healthy breakfast, eating healthy foods and snacks, drinking healthy drinks, and engaging in physical activity. The MB-HSBI was developed through several phases as part of a multisite study on modifying and preventing obesity. A central aspect of the larger study was to identify motivators of and barriers to the targeted health-smart behaviors among African American, Asian, Hispanic, and White adults. After establishing content validity and preliminary pilot testing, the MB-HSBI was administered to a national sample of 926 culturally diverse adults. Factor analyses and most of the internal consistency results supported multiple scales and subscales measuring motivators of and barriers to each of the targeted health-smart behavior domains. Scores correlated in expected directions with health self-efficacy and with importance of health-related behavioral goals. Pending further psychometric support of the MB-HSBI, this inventory or selected scales from it may serve as flexible and novel tools for (a) assessing motivators of and barriers to health-smart behaviors in community and clinical health promotion research studies and (b) developing assessment-based, culturally sensitive intervention programs that are customized to address the motivators of and barriers to health-smart behaviors identified in target communities, particularly those communities whose members are mostly racial/ethnic minorities and/or have low family incomes. 2011 APA, all rights reserved

Barriers to Professionalism in the Native-Speaking English Teacher Scheme in Hong Kong

ERIC Educational Resources Information Center

Moorhouse, Benjamin Luke

2017-01-01

This article reports on a small-scale exploratory study that examined how native-speaking English teachers (NETs) working in the Primary Native-speaking English Teacher (PNET) Scheme construct their professional identity(ies) and explored the barriers to their professionalism that exist within their role and context. Data were collected using…

A field and modeling study to assess the potential mitigation of near-road pollution by vegetative and structural barriers

EPA Science Inventory

Recent modeling and field studies have demonstrated that roadside structures such as noise barriers or tree stands, may significantly affect the local-scale transport of on-road emissions to areas located adjacent to major roadways. When directly downwind of a major roadway, conc...

The effect of a walking program on perceived benefits and barriers to exercise in postmenopausal African American women.

PubMed

Williams, Bernadette R; Bezner, Janet; Chesbro, Steven B; Leavitt, Ronnie

2006-01-01

Rates of exercise participation among African Americans is low. Identifying and overcoming perceived benefits/ barriers unique to African American women (AAW) may increase their exercise participation. The purpose of this study was to describe perceived benefits/barriers to exercise in AAW before and after participation in a walking program. Thirty-five postmenopausal AAW participated in a 7-week structured walking program with 2 walking goals. Perceived benefits and barriers to exercise were assessed using the Exercise Benefits/Barriers Scale at the beginning and end of the program. Participants engaged in a postintervention interview to further assess benefits/barriers to exercise participation. Perceived benefits/barriers to exercise did not change significantly with participation in a walking program. Lack of time due to work and family responsibilities affected achievement of the brisk walking goal. Postmenopausal AAW in this study strongly believed in the benefits of exercising and had increased levels of participation in a walking program when lack of time was not a barrier. Overcoming this barrier is the true challenge to health care professionals.

Scaling analysis and instantons for thermally assisted tunneling and quantum Monte Carlo simulations

NASA Astrophysics Data System (ADS)

Jiang, Zhang; Smelyanskiy, Vadim N.; Isakov, Sergei V.; Boixo, Sergio; Mazzola, Guglielmo; Troyer, Matthias; Neven, Hartmut

2017-01-01

We develop an instantonic calculus to derive an analytical expression for the thermally assisted tunneling decay rate of a metastable state in a fully connected quantum spin model. The tunneling decay problem can be mapped onto the Kramers escape problem of a classical random dynamical field. This dynamical field is simulated efficiently by path-integral quantum Monte Carlo (QMC). We show analytically that the exponential scaling with the number of spins of the thermally assisted quantum tunneling rate and the escape rate of the QMC process are identical. We relate this effect to the existence of a dominant instantonic tunneling path. The instanton trajectory is described by nonlinear dynamical mean-field theory equations for a single-site magnetization vector, which we solve exactly. Finally, we derive scaling relations for the "spiky" barrier shape when the spin tunneling and QMC rates scale polynomially with the number of spins N while a purely classical over-the-barrier activation rate scales exponentially with N .

Ring distributions leading to species formation: a global topographic analysis of geographic barriers associated with ring species

PubMed Central

2012-01-01

Background In the mid 20th century, Ernst Mayr and Theodosius Dobzhansky championed the significance of circular overlaps or ring species as the perfect demonstration of speciation, yet in the over 50 years since, only a handful of such taxa are known. We developed a topographic model to evaluate whether the geographic barriers that favor processes leading to ring species are common or rare, and to predict where other candidate ring barriers might be found. Results Of the 952,147 geographic barriers identified on the planet, only about 1% are topographically similar to barriers associated with known ring taxa, with most of the likely candidates occurring in under-studied parts of the world (for example, marine environments, tropical latitudes). Predicted barriers separate into two distinct categories: (i) single cohesive barriers (< 50,000 km2), associated with taxa that differentiate at smaller spatial scales (salamander: Ensatina eschscholtzii; tree: Acacia karroo); and (ii) composite barriers - formed by groups of barriers (each 184,000 to 1.7 million km2) in close geographic proximity (totaling 1.9 to 2.3 million km2) - associated with taxa that differentiate at larger spatial scales (birds: Phylloscopus trochiloides and Larus (sp. argentatus and fuscus)). When evaluated globally, we find a large number of cohesive barriers that are topographically similar to those associated with known ring taxa. Yet, compared to cohesive barriers, an order of magnitude fewer composite barriers are similar to those that favor ring divergence in species with higher dispersal. Conclusions While these findings confirm that the topographic conditions that favor evolutionary processes leading to ring speciation are, in fact, rare, they also suggest that many understudied natural systems could provide valuable demonstrations of continuous divergence towards the formation of new species. Distinct advantages of the model are that it (i) requires no a priori information on the relative importance of features that define barriers, (ii) can be replicated using any kind of continuously distributed environmental variable, and (iii) generates spatially explicit hypotheses of geographic species formation. The methods developed here - combined with study of the geographical ecology and genetics of taxa in their environments - should enable recognition of ring species phenomena throughout the world. PMID:22410314

Identifying barriers to remaining physically active after rehabilitation: differences in perception between physical therapists and older adult patients.

PubMed

Zalewski, Kathryn; Alt, Carlynn; Arvinen-Barrow, Monna

2014-06-01

Cross-sectional study. To describe readiness for change and barriers to physical activity in older adults and to contrast perceptions of physical therapists and patients using the Barriers to Being Active Quiz. Regular physical activity is vital to recovery after discharge from physical therapy. Physical therapists are positioned to support change in physical activity habits for those transitioning to home care. Understanding of readiness for change and barriers to physical activity could optimize recovery. Thirteen physical therapists enrolled in the study and invited patients who met the inclusion criteria to enroll (79 patients enrolled). The physical therapists provided the ICD-9 code, the physical therapist diagnosis, and completed the Barriers to Being Active Quiz as they perceived their patients would. The enrolled patients provided demographics and filled out the Satisfaction With Life Scale, the stages-of-change scale for physical activity, and the Barriers to Being Active Quiz. Patients were predominantly in the early stages of readiness for change. Both patients and physical therapists identified lack of willpower as the primary barrier to physical activity. Patients identified lack of willpower and social influence as critical barriers more often than physical therapists, whereas physical therapists identified fear of injury and lack of time more often than their patients did. Differences between physical therapists and their patients were noted for fear of injury (z = 2.66, P = .008) and lack of time (z = 3.46, P = .001). The stage of change for physical activity impacted perception of social influence (χ2 = 9.64, P<.05), lack of willpower (χ2 = 21.91, P<.01), and lack of skill (χ2 = 12.46, P<.05). Women ranked fear of injury higher than men did (χ2 = 6.76, P<.01). Understanding readiness for change in and barriers to physical activity may allow physical therapists to better tailor intervention strategies to impact physical activity behavior change.

Barriers to Exercise in People With Parkinson Disease

PubMed Central

Boudreau, Jennifer K.; DeAngelis, Tamara R.; Brown, Lisa E.; Cavanaugh, James T.; Earhart, Gammon M.; Ford, Matthew P.; Foreman, K. Bo; Dibble, Leland E.

2013-01-01

Background Exercise is known to reduce disability and improve quality of life in people with Parkinson disease (PD). Although barriers to exercise have been studied in older adults, barriers in people with chronic progressive neurological diseases, such as PD, are not well defined. Objective The purpose of this study was to identify perceived barriers to exercise in people with PD. Design The study had a cross-sectional design. Methods People who had PD, dwelled in the community, and were at stage 2.4 on the Hoehn and Yahr scale participated in this cross-sectional study (N=260; mean age=67.7 years). Participants were divided into an exercise group (n=164) and a nonexercise group (n=96). Participants self-administered the barriers subscale of the Physical Fitness and Exercise Activity Levels of Older Adults Scale, endorsing or denying specific barriers to exercise participation. Multivariate logistic regression analysis was used to examine the contribution of each barrier to exercise behavior, and odds ratios were reported. Results Three barriers were retained in the multivariate regression model. The nonexercise group had significantly greater odds of endorsing low outcome expectation (ie, the participants did not expect to derive benefit from exercise) (odds ratio [OR]=3.93, 95% confidence interval [CI]=2.08–7.42), lack of time (OR=3.36, 95% CI=1.55–7.29), and fear of falling (OR=2.35, 95% CI=1.17–4.71) than the exercise group. Limitations The cross-sectional nature of this study limited the ability to make causal inferences. Conclusions Low outcome expectation from exercise, lack of time to exercise, and fear of falling appear to be important perceived barriers to engaging in exercise in people who have PD, are ambulatory, and dwell in the community. These may be important issues for physical therapists to target in people who have PD and do not exercise regularly. The efficacy of intervention strategies to facilitate exercise adherence in people with PD requires further investigation. PMID:23288910

Barriers to exercise in people with Parkinson disease.

PubMed

Ellis, Terry; Boudreau, Jennifer K; DeAngelis, Tamara R; Brown, Lisa E; Cavanaugh, James T; Earhart, Gammon M; Ford, Matthew P; Foreman, K Bo; Dibble, Leland E

2013-05-01

Exercise is known to reduce disability and improve quality of life in people with Parkinson disease (PD). Although barriers to exercise have been studied in older adults, barriers in people with chronic progressive neurological diseases, such as PD, are not well defined. The purpose of this study was to identify perceived barriers to exercise in people with PD. The study had a cross-sectional design. People who had PD, dwelled in the community, and were at stage 2.4 on the Hoehn and Yahr scale participated in this cross-sectional study (N=260; mean age=67.7 years). Participants were divided into an exercise group (n=164) and a nonexercise group (n=96). Participants self-administered the barriers subscale of the Physical Fitness and Exercise Activity Levels of Older Adults Scale, endorsing or denying specific barriers to exercise participation. Multivariate logistic regression analysis was used to examine the contribution of each barrier to exercise behavior, and odds ratios were reported. Three barriers were retained in the multivariate regression model. The nonexercise group had significantly greater odds of endorsing low outcome expectation (ie, the participants did not expect to derive benefit from exercise) (odds ratio [OR]=3.93, 95% confidence interval [CI]=2.08-7.42), lack of time (OR=3.36, 95% CI=1.55-7.29), and fear of falling (OR=2.35, 95% CI=1.17-4.71) than the exercise group. The cross-sectional nature of this study limited the ability to make causal inferences. Low outcome expectation from exercise, lack of time to exercise, and fear of falling appear to be important perceived barriers to engaging in exercise in people who have PD, are ambulatory, and dwell in the community. These may be important issues for physical therapists to target in people who have PD and do not exercise regularly. The efficacy of intervention strategies to facilitate exercise adherence in people with PD requires further investigation.

Differential Rollover Risk in Vehicle-to-Traffic Barrier Collisions

PubMed Central

Gabauer, Douglas J.; Gabler, Hampton C.

2009-01-01

In the roadside safety community, there has been debate over the influence of vehicle and barrier type on rollover rates in traffic barrier crashes. This study investigated rollover rates between sport utility vehicles (SUVs), pickup trucks, and cars in vehicle-traffic barrier crashes and has examined the effect of barrier type on rollover risk for concrete barrier and metal barrier impacts. The analysis included 955 barrier impact cases that were selected from 11-years of in-depth crash data available through the National Automotive Sampling System (NASS) / Crashworthiness Data System (CDS). In real world tow-away level longitudinal barrier collisions, the most important predictors of vehicle rollover were found to be vehicle type and whether the vehicle was tracking prior to barrier impact. Based on binary logistic regression, SUVs were found to have 8 times the risk of rollover as cars in barrier impacts. Although pickups were found to have an increased risk of rollover compared to cars, the risk was not as pronounced as that found for SUVs. This finding has direct implications for the full scale crash testing of longitudinal barriers as the testing procedures have been predicated on the assumption that the pickup truck provides a critical or worst case impact scenario. In towaway crashes, our study does not support the notion that concrete barriers have a higher risk of vehicle rollover than metal beam barriers. PMID:20184839

Monolithic barrier-all-around high electron mobility transistor with planar GaAs nanowire channel.

PubMed

Miao, Xin; Zhang, Chen; Li, Xiuling

2013-06-12

High-quality growth of planar GaAs nanowires (NWs) with widths as small as 35 nm is realized by comprehensively mapping the parameter space of group III flow, V/III ratio, and temperature as the size of the NWs scales down. Using a growth mode modulation scheme for the NW and thin film barrier layers, monolithically integrated AlGaAs barrier-all-around planar GaAs NW high electron mobility transistors (NW-HEMTs) are achieved. The peak extrinsic transconductance, drive current, and effective electron velocity are 550 μS/μm, 435 μA/μm, and ~2.9 × 10(7) cm/s, respectively, at 2 V supply voltage with a gate length of 120 nm. The excellent DC performance demonstrated here shows the potential of this bottom-up planar NW technology for low-power high-speed very-large-scale-integration (VLSI) circuits.

Major coastal impact induced by a 1000-year storm event

PubMed Central

Fruergaard, Mikkel; Andersen, Thorbjørn J.; Johannessen, Peter N.; Nielsen, Lars H.; Pejrup, Morten

2013-01-01

Extreme storms and storm surges may induce major changes along sandy barrier coastlines, potentially causing substantial environmental and economic damage. We show that the most destructive storm (the 1634 AD storm) documented for the northern Wadden Sea within the last thousand years both caused permanent barrier breaching and initiated accumulation of up to several metres of marine sand. An aggradational storm shoal and a prograding shoreface sand unit having thicknesses of up to 8 m and 5 m respectively were deposited as a result of the storm and during the subsequent 30 to 40 years long healing phase, on the eroded shoreface. Our results demonstrate that millennial-scale storms can induce large-scale and long-term changes on barrier coastlines and shorefaces, and that coastal changes assumed to take place over centuries or even millennia may occur in association with and be triggered by a single extreme storm event.

Flexible Ultra Moisture Barrier Film for Thin-Film Photovoltaic Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

David M. Dean

2012-10-30

Flexible Thin-film photovoltaic (TFPV) is a low cost alternative to incumbent c-Si PV products as it requires less volume of costly semiconductor materials and it can potentially reduce installation cost. Among the TFPV options, copper indium gallium diselenide (CIGS) has the highest efficiency and is believed to be one of the most attractive candidates to achieve PV cost reduction. However, CIGS cells are very moisture sensitive and require module water vapor transmission rate (WVTR) of less than 1x10-4 gram of water per square meter per day (g-H2O/m2/day). Successful development and commercialization of flexible transparent ultra moisture barrier film is themore » key to enable flexible CIGS TFPV products, and thus enable ultimate PV cost reduction. At DuPont, we have demonstrated at lab scale that we can successfully make polymer-based flexible transparent ultra moisture barrier film by depositing alumina on polymer films using atomic layer deposition (ALD) technology. The layer by layer ALD approach results in uniform and amorphous structure which effectively reduces pinhole density of the inorganic coating on the polymer, and thus allow the fabrication of flexible barrier film with WVTR of 10-5 g-H2O/m2/day. Currently ALD is a time-consuming process suitable only for high-value, relatively small substrates. To successfully commercialize the ALD-on-plastic technology for the PV industry, there is the need to scale up this technology and improve throughput. The goal of this contract work was to build a prototype demonstrating that the ALD technology could be scaled-up for commercial use. Unfortunately, the prototype failed to produce an ultra-barrier film by the close of the project.« less

Theory of dynamic barriers, activated hopping, and the glass transition in polymer melts

NASA Astrophysics Data System (ADS)

Schweizer, Kenneth S.; Saltzman, Erica J.

2004-07-01

A statistical mechanical theory of collective dynamic barriers, slow segmental relaxation, and the glass transition of polymer melts is developed by combining, and in some aspects extending, methods of mode coupling, density functional, and activated hopping transport theories. A coarse-grained description of polymer chains is adopted and the melt is treated as a liquid of segments. The theory is built on the idea that collective density fluctuations on length scales considerably longer than the local cage scale are of primary importance in the deeply supercooled regime. The barrier hopping or segmental relaxation time is predicted to be a function primarily of a single parameter that is chemical structure, temperature, and pressure dependent. This parameter depends on the material-specific dimensionless amplitude of thermal density fluctuations (compressibility) and a reduced segmental density determined by the packing length and backbone characteristic ratio. Analytic results are derived for a crossover temperature Tc, collective barrier, and glass transition temperature Tg. The relation of these quantities to structural and thermodynamic properties of the polymer melt is established. A universal power-law scaling behavior of the relaxation time below Tc is predicted based on identification of a reduced temperature variable that quantifies the breadth of the supercooled regime. Connections between the ratio Tc/Tg, two measures of dynamic fragility, and the magnitude of the local relaxation time at Tg logically follow. Excellent agreement with experiment is found for these generic aspects, and the crucial importance of the experimentally observed near universality of the dynamic crossover time is established. Extensions of the theory to treat the full chain dynamics, heterogeneity, barrier fluctuations, and nonpolymeric thermal glass forming liquids are briefly discussed.

Lab Experiments Probe Interactions Between Dilute Pyroclastic Density Currents and 3D Barriers

NASA Astrophysics Data System (ADS)

Fauria, K.; Andrews, B. J.; Manga, M.

2014-12-01

We conducted scaled laboratory experiments of unconfined dilute pyroclastic density currents (PDCs) to examine interactions between three - dimensional obstacles and dilute PDCs. While it is known that PDCs can surmount barriers by converting kinetic energy into potential energy, the signature of topography on PDC dynamics is unclear. To examine the interplay between PDCs and topography, we turbulently suspended heated and ambient-temperature 20 μm talc powder in air within an 8.5 x 6.1 x 2.6 m tank. Experimental parameters (Froude number, densimetric and thermal Richardson number, particle Stokes and Settling numbers) were scaled such that the experimental currents were dynamically similar to natural PCS. The Reynolds number, however, is much smaller than in natural currents, but still large enough for the flows to be turbulent. We placed cylindrical and ridge-like objects in the path of the currents, illuminated the currents with orthogonal laser sheets, and recorded each experiment with high definition cameras. We observed currents surmounting ridge-like barriers (barrier height = current height). Slanted ridges redirected the currents upward and parallel to the upstream face of the ridges (~45° from horizontal). Down stream of the slanted ridges, ambient-temperature currents reattached to the floor. By comparison, hot currents reversed buoyancy and lifted off. These observations suggest that obstacles enhance air entrainment, a process key to affecting runout distance and the depletion of fine particles in ignimbrites. Moreover, we observed vortex shedding in the wake of cylinders. Our experiments demonstrate that barriers of various shapes affect PDC dynamics and can shorten PDC runout distances. Understanding the effects of topography on PDCs is required for interpreting many deposits because processes such as vortex shedding and topographically-induced changes in turbulent length scales and entrainment likely leave depositional signatures.

International bioenergy synthesis-lessons learned and opportunities for the western United States

Treesearch

D.L. Nicholls; R. Monserud; D. Dykstra

2009-01-01

This synthesis examines international opportunities for utilizing biomass for energy at several different scales, with an emphasis on larger scale electrical power generation at stand-alone facilities as well as smaller scale thermal heating applications such as those at governmental, educational, or other institutional facilities. It identifies barriers that can...

Setting Learning Analytics in Context: Overcoming the Barriers to Large-Scale Adoption

ERIC Educational Resources Information Center

Ferguson, Rebecca; Macfadyen, Leah P.; Clow, Doug; Tynan, Belinda; Alexander, Shirley; Dawson, Shane

2014-01-01

A core goal for most learning analytic projects is to move from small-scale research towards broader institutional implementation, but this introduces a new set of challenges because institutions are stable systems, resistant to change. To avoid failure and maximize success, implementation of learning analytics at scale requires explicit and…

Effects of Discipline-based Career Course on Nursing Students' Career Search Self-efficacy, Career Preparation Behavior, and Perceptions of Career Barriers.

PubMed

Park, Soonjoo

2015-09-01

The purpose of this study was to investigate the effectiveness of a discipline-based career course on perceptions of career barriers, career search self-efficacy, and career preparation behavior of nursing students. Differences in career search self-efficacy and career preparation behavior by the students' levels of career barriers were also examined. The study used a modified one-group, pretest-posttest design. The convenience sample consisted of 154 undergraduate nursing students in a university. The discipline-based career course consisted of eight sessions, and was implemented for 2 hours per session over 8 weeks. The data were collected from May to June in 2012 and 2013 using the following instruments: the Korean Career Indecision Inventory, the Career Search Efficacy Scale, and the Career Preparation Behavior Scale. Descriptive statistics, paired t test, and analysis of covariance were used to analyze the data. Upon the completion of the discipline-based career course, students' perceptions of career barriers decreased and career search self-efficacy and career preparation behavior increased. Career search self-efficacy and career preparation behavior increased in students with both low and high levels of career barriers. The difference between the low and high groups was significant for career search self-efficacy but not for career preparation behavior. The discipline-based career course was effective in decreasing perceptions of career barriers and increasing career search self-efficacy and career preparation behavior among nursing students. Copyright © 2015. Published by Elsevier B.V.

Barriers to Quitting Smoking among Substance Dependent Patients Predict Smoking Cessation Treatment Outcome

PubMed Central

Martin, Rosemarie A.; Cassidy, Rachel; Murphy, Cara M.; Rohsenow, Damaris J.

2016-01-01

For smokers with substance use disorders (SUD), perceived barriers to quitting smoking include concerns unique to effects on sobriety as well as usual concerns. We expanded our Barriers to Quitting Smoking in Substance Abuse Treatment (BQS-SAT) scale, added importance ratings, validated it, and then used the importance scores to predict smoking treatment response in smokers with substance use disorders (SUD) undergoing smoking treatment in residential treatment programs in two studies (n = 184 and 340). Both components (General Barriers, Weight Concerns) were replicated with excellent internal consistency reliability. Construct validity was supported by significant correlations with pretreatment nicotine dependence, smoking variables, smoking self-efficacy, and expected effects of smoking. General Barriers significantly predicted 1-month smoking abstinence, frequency and heaviness, and 3-month smoking frequency; Weight Concerns predicted 1-month smoking frequency. Implications involve addressing barriers with corrective information in smoking treatment for smokers with SUD. PMID:26979552

Barriers to Quitting Smoking Among Substance Dependent Patients Predict Smoking Cessation Treatment Outcome.

PubMed

Martin, Rosemarie A; Cassidy, Rachel N; Murphy, Cara M; Rohsenow, Damaris J

2016-05-01

For smokers with substance use disorders (SUD), perceived barriers to quitting smoking include concerns unique to effects on sobriety as well as usual concerns. We expanded our Barriers to Quitting Smoking in Substance Abuse Treatment (BQS-SAT) scale, added importance ratings, validated it, and then used the importance scores to predict smoking treatment response in smokers with substance use disorders (SUD) undergoing smoking treatment in residential treatment programs in two studies (n=184 and 340). Both components (general barriers, weight concerns) were replicated with excellent internal consistency reliability. Construct validity was supported by significant correlations with pretreatment nicotine dependence, smoking variables, smoking self-efficacy, and expected effects of smoking. General barriers significantly predicted 1-month smoking abstinence, frequency and heaviness, and 3-month smoking frequency; weight concerns predicted 1-month smoking frequency. Implications involve addressing barriers with corrective information in smoking treatment for smokers with SUD. Copyright © 2016 Elsevier Inc. All rights reserved.

Micro heat barrier

DOEpatents

Marshall, Albert C.; Kravitz, Stanley H.; Tigges, Chris P.; Vawter, Gregory A.

2003-08-12

A highly effective, micron-scale micro heat barrier structure and process for manufacturing a micro heat barrier based on semiconductor and/or MEMS fabrication techniques. The micro heat barrier has an array of non-metallic, freestanding microsupports with a height less than 100 microns, attached to a substrate. An infrared reflective membrane (e.g., 1 micron gold) can be supported by the array of microsupports to provide radiation shielding. The micro heat barrier can be evacuated to eliminate gas phase heat conduction and convection. Semi-isotropic, reactive ion plasma etching can be used to create a microspike having a cusp-like shape with a sharp, pointed tip (<0.1 micron), to minimize the tip's contact area. A heat source can be placed directly on the microspikes. The micro heat barrier can have an apparent thermal conductivity in the range of 10.sup.-6 to 10.sup.-7 W/m-K. Multiple layers of reflective membranes can be used to increase thermal resistance.

Optimistic barrier synchronization

NASA Technical Reports Server (NTRS)

Nicol, David M.

1992-01-01

Barrier synchronization is fundamental operation in parallel computation. In many contexts, at the point a processor enters a barrier it knows that it has already processed all the work required of it prior to synchronization. The alternative case, when a processor cannot enter a barrier with the assurance that it has already performed all the necessary pre-synchronization computation, is treated. The problem arises when the number of pre-sychronization messages to be received by a processor is unkown, for example, in a parallel discrete simulation or any other computation that is largely driven by an unpredictable exchange of messages. We describe an optimistic O(log sup 2 P) barrier algorithm for such problems, study its performance on a large-scale parallel system, and consider extensions to general associative reductions as well as associative parallel prefix computations.

Adolescents' Self-Efficacy to Overcome Barriers to Physical Activity Scale

ERIC Educational Resources Information Center

Dwyer, John J. M.; Chulak, Tala; Maitland, Scott; Allison, Kenneth R.; Lysy, Daria C.; Faulkner, Guy E. J.; Sheeshka, Judy

2012-01-01

This paper describes a revised measure of self-efficacy to overcome barriers to moderate and vigorous physical activity in a sample of 484 high school students in Toronto, Ontario. The students had a mean age of 15.3 years. Principal axis factoring with oblique rotation yielded five factors: self-efficacy to overcome internal, harassment, physical…

CAPSTONE REPORT ON THE APPLICATION, MONITORING, AND PERFORMANCE OF PERMEABLE REACTIVE BARRIERS FOR GROUND-WATER REMEDIATION: VOL. 1 PERFORMANCE EVALUATIONS AT TWO SITES

EPA Science Inventory

The purpose of this document is to provide detailed performance monitoring data on full-scale Permeable Reactive Barriers (PRBs) installed to treat contaminated ground water at two different sites. This report will fill a need for a readily available source of information for si...

Jordanian dialysis patients' perceived exercise benefits and barriers: a correlation study.

PubMed

Darawad, Muhammad W; Khalil, Amani A

2013-01-01

To investigate Jordanian end-stage renal disease (ESRD)patients' perceived exercise benefits and barriers, and their correlation with patients' demographic variables and dialysis measures. A descriptive correlational study was conducted using cross-sectional survey, using a convenience sample of 190 ESRD dialyzed patients who were recruited from eight hospitals in Jordan. Participants significantly perceived exercise benefits (M= 2.88/4, SD± .67) higher than barriers (M= 2.66, SD± .62). The most frequent perceived exercise benefits were preventing muscular atrophy and improving mood, whereas tiredness and lower-extremity fatigue were the most frequent exercise barriers. Finally, acceptable values of Cronbach's Alpha were revealed for perceived exercise subscale, barriers subscale, and total scale (α= .88, .81, and .70, respectively). Participants focused more on exercise benefits than barriers, and on direct exercise benefits and barriers than the indirect. The results of this study have important implications for the efforts that aim at improving ESRD patients' exercise behaviors. © 2013 Association of Rehabilitation Nurses.

Large-scale field testing on flexible shallow landslide barriers

NASA Astrophysics Data System (ADS)

Bugnion, Louis; Volkwein, Axel; Wendeler, Corinna; Roth, Andrea

2010-05-01

Open shallow landslides occur regularly in a wide range of natural terrains. Generally, they are difficult to predict and result in damages to properties and disruption of transportation systems. In order to improve the knowledge about the physical process itself and to develop new protection measures, large-scale field experiments were conducted in Veltheim, Switzerland. Material was released down a 30° inclined test slope into a flexible barrier. The flow as well as the impact into the barrier was monitored using various measurement techniques. Laser devices recording flow heights, a special force plate measuring normal and shear basal forces as well as load cells for impact pressures were installed along the test slope. In addition, load cells were built in the support and retaining cables of the barrier to provide data for detailed back-calculation of load distribution during impact. For the last test series an additional guiding wall in flow direction on both sides of the barrier was installed to achieve higher impact pressures in the middle of the barrier. With these guiding walls the flow is not able to spread out before hitting the barrier. A special constructed release mechanism simulating the sudden failure of the slope was designed such that about 50 m3 of mixed earth and gravel saturated with water can be released in an instant. Analysis of cable forces combined with impact pressures and velocity measurements during a test series allow us now to develop a load model for the barrier design. First numerical simulations with the software tool FARO, originally developed for rockfall barriers and afterwards calibrated for debris flow impacts, lead already to structural improvements on barrier design. Decisive for the barrier design is the first dynamic impact pressure depending on the flow velocity and afterwards the hydrostatic pressure of the complete retained material behind the barrier. Therefore volume estimation of open shallow landslides by assessing the thickness of the failure layer and the width of the possible failure are essential for the required barrier design parameter height and width. First results of the calculated drag coefficients of dynamic impact pressure measurements showed that the dynamic coefficient cw is much lower than 1.0 which is contradictory to most of existing dimensioning property protection guidelines. It appears to us that special adaptation to the system like smaller mesh sizes and special ground-barrier interface compared to normal rock-fall barriers and channelised debris flow barriers are necessary to improve the retention behavior of shallow landslide barriers. Detailed analysis of the friction coefficient in relationship with pore water pressure measurements gives interesting insights into the dynamic of fluid-solid mixed flows. Impact pressures dependencies on flow features are analyzed and discussed with respect to existing models and guidelines for shallow landslides.

Congruent biogeographical disjunctions at a continent-wide scale: Quantifying and clarifying the role of biogeographic barriers in the Australian tropics.

PubMed

Edwards, Robert D; Crisp, Michael D; Cook, Dianne H; Cook, Lyn G

2017-01-01

To test whether novel and previously hypothesized biogeogaphic barriers in the Australian Tropics represent significant disjunction points or hard barriers, or both, to the distribution of plants. Australian tropics: Australian Monsoon Tropics and Australian Wet Tropics. The presence or absence of 6,861 plant species was scored across 13 putative biogeographic barriers in the Australian Tropics, including two that have not previously been recognised. Randomizations of these data were used to test whether more species showed disjunctions (gaps in distribution) or likely barriers (range limits) at these points than expected by chance. Two novel disjunctions in the Australian Tropics flora are identified in addition to eleven putative barriers previously recognized for animals. Of these, eleven disjunction points (all within the Australian Monsoon Tropics) were found to correspond to range-ending barriers to a significant number of species, while neither of the two disjunctions found within the Australian Wet Tropics limited a significant number of species' ranges. Biogeographic barriers present significant distributional limits to native plant species in the Australian Monsoon Tropics but not in the Australian Wet Tropics.

Impact of sunscreens on preventing UVR-induced effects in nevi: in vivo study comparing protection using a physical barrier vs sunscreen.

PubMed

Carrera, Cristina; Puig-Butillè, Joan A; Aguilera, Paula; Ogbah, Zighereda; Palou, Josep; Lecha, Mario; Malvehy, Josep; Puig, Susana

2013-07-01

Sun damage is the most important environmental factor associated with malignant melanoma. To address the health threat, as well as the economic burden, primary prevention and early detection are crucial. To test the efficacy of a topical sunscreen in the prevention of UV-induced effects in nevi. Prospective study of nevi protected by sunscreen vs a physical barrier. Twenty-three nevi from 20 patients attending a referral hospital. Half of each nevus was protected by either a physical barrier or a sunscreen. Lesions were completely irradiated by a single dose of UV-B. In vivo examination before and 7 days after irradiation and histopathologic-immunopathologic evaluation after excision on the seventh day. The most frequent clinical changes after UV radiation were pigmentation, scaling, and erythema; the most frequent dermoscopic changes were increased globules/dots, blurred network, regression, and dotted vessels. Both physical barrier- and sunscreen-protected areas showed some degree of these changes. More than 30% (7) of nevi did not show any change on clinical examination, and 18% (4) had no dermoscopic change. Immunohistopathologic differences between the halves of each nevus were demonstrable even when in vivo examination detected nothing. Parakeratotic scale, increased number and activation of superficial melanocytes, and keratinocyte proliferation were the most remarkable features. The only difference between both barriers was more enhanced melanocytic activation and regression features in the sunscreen group. No phenotypic features were found to predict a specific UV-B response. Both physical barriers and sunscreens can partially prevent UV-B effects on nevi. Subclinical UV radiation effects, not always associated with visible changes, can develop even after protection. Sunscreens are not quite as effective as physical barriers in the prevention of inflammatory UV-B-induced effects.

The Association Between Self-Management Barriers and Self-Efficacy in Chinese Patients with Type 2 Diabetes: The Mediating Role of Appraisal.

PubMed

Cheng, Li; Sit, Janet W H; Leung, Doris Y P; Li, Xiaomei

2016-10-01

Patients with higher levels of self-management barriers are more likely to exhibit a lower level of self-efficacy. However, the theoretically meaningful mechanisms underlying the association between the two variables have not yet been established. Informed by the Transactional Model of Stress and Coping, this study aimed to examine the potential role of diabetes appraisal on the association of self-management barriers and self-efficacy in patients with type 2 diabetes mellitus. This article presents the secondary data analyses of a multicenter, cross-sectional study. A sample of 346 adults with type 2 diabetes was interviewed, using the Personal Diabetes Questionnaire, the Appraisal of Diabetes scale, the Diabetes Empowerment Scale-Short Form, and the Summary of Diabetes Self-Care Activities. Structure equation modeling was performed with 10,000 bootstrap samples using Mplus 7. The hypothesized model provided a good fit to the data (χ 2 = 22.975, df = 33; p = .1144; CFI = 0.989; SRMR = 0.036; RMSEA = 0.042). The mediating effect of diabetes appraisal on the association of self-management barriers and self-efficacy was significant (β = -0.521; 95% CI: -0.865, -0.283), explaining 44.82% of the total effect of barriers on self-efficacy. Significant associations were also detected between diet knowledge and diabetes appraisal (β = 0.148, p = .047). Diabetes appraisal plays a mediating role in the association between self-management barriers and self-efficacy in patients with type 2 diabetes. Reflecting on patients' appraisal of diabetes can help to develop evidence-based and patient-centered interventions. Interventions that enhance individuals' positive appraisal of diabetes have the potential to buffer the negative effects of self-management barriers on self-efficacy. © 2016 Sigma Theta Tau International.

Numerical analysis of similarity of barrier discharges in the 0.95 Ne/0.05 Xe mixture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Avtaeva, S. V.; Kulumbaev, E. B.

2009-04-15

Established dynamic regimes of similar (with a scale factor of 10) barrier discharges in the 0.95 Ne/0.05 Xe mixture are simulated in a one-dimensional drift-diffusion model. The similarity is examined of barrier discharges excited in gaps of lengths 0.4 and 4 mm at gas pressures of 350 and 35 Torr and dielectric layer thicknesses of 0.2 and 2 mm, the frequencies of the 400-V ac voltage applied to the discharge electrodes being 100 and 10 kHz, respectively.

How can we teach EBM in clinical practice? An analysis of barriers to implementation of on-the-job EBM teaching and learning.

PubMed

Oude Rengerink, Katrien; Thangaratinam, Shakila; Barnfield, Gemma; Suter, Katja; Horvath, Andrea R; Walczak, Jacek; Wełmińska, Anna; Weinbrenner, Susanne; Meyerrose, Berit; Arvanitis, Theodoros N; Onody, Rita; Zanrei, Gianni; Kunz, Regina; Arditi, Chantal; Burnand, Bernard; Gee, Harry; Khan, Khalid S; Mol, Ben W J

2011-01-01

Evidence-based medicine (EBM) improves the quality of health care. Courses on how to teach EBM in practice are available, but knowledge does not automatically imply its application in teaching. We aimed to identify and compare barriers and facilitators for teaching EBM in clinical practice in various European countries. A questionnaire was constructed listing potential barriers and facilitators for EBM teaching in clinical practice. Answers were reported on a 7-point Likert scale ranging from not at all being a barrier to being an insurmountable barrier. The questionnaire was completed by 120 clinical EBM teachers from 11 countries. Lack of time was the strongest barrier for teaching EBM in practice (median 5). Moderate barriers were the lack of requirements for EBM skills and a pyramid hierarchy in health care management structure (median 4). In Germany, Hungary and Poland, reading and understanding articles in English was a higher barrier than in the other countries. Incorporation of teaching EBM in practice faces several barriers to implementation. Teaching EBM in clinical settings is most successful where EBM principles are culturally embedded and form part and parcel of everyday clinical decisions and medical practice.

Factors related to Psychosocial Barriers to Drug Treatment among Chinese Drug Users

PubMed Central

Kelly, Brian C; Liu, Tieqiao; Zhang, Guanbai; Hao, Wei; Wang, Jichuan

2014-01-01

Although substance abuse treatment has been considerably scaled up in China, impediments to accessing these services remain among drug users. The authors examine the primary psychosocial barriers to drug treatment in this population and evaluate factors associated with these barriers. Barriers to accessing drug treatment were measured using the Barriers to Treatment Inventory (BTI). A Structural Equation Model was used to examine whether the internal barriers were associated with treatment history and frequent methamphetamine use as well as how demographic characteristics influence such barriers. We found four primary factors of internal barriers to drug treatment – absence of problem, negative social support, fear of treatment, and privacy concerns – to fit well. Demographic factors, notably age and employment status, indirectly influence barriers to treatment via other factors. Frequency of methamphetamine use and drug treatment history are directly associated with the absence of problem and negative social support dimensions of the BTI, and it is through these pathways that demographic factors such as age and employment status shape barriers to treatment. The findings indicate that perceived absence of a problem and negative social support are the barriers most influenced by the personal domains of Chinese drug users’ lives. Efforts to engage drug users in China about drug treatment options may consider how these barriers are differentially perceived in order to effectively reach this population. PMID:24813554

Measuring Parent Time Scarcity and Fatigue as Barriers to Meal Planning and Preparation: Quantitative Scale Development

ERIC Educational Resources Information Center

Storfer-Isser, Amy; Musher-Eizenman, Dara

2013-01-01

Objective: To examine the psychometric properties of 9 quantitative items that assess time scarcity and fatigue as parent barriers to planning and preparing meals for their children. Methods: A convenience sample of 342 parents of children aged 2-6 years completed a 20-minute online survey. Exploratory factor analysis was used to examine the…

Development of an Instrument to Measure Preservice Teachers' Technology Skills, Technology Beliefs, and Technology Barriers

ERIC Educational Resources Information Center

Brush, Thomas; Glazewski, Krista D.; Hew, Khe Foon

2008-01-01

The purpose of this study was to develop and field-test the Technology Skills, Beliefs, and Barriers scale and to determine its validity and reliability for use with preservice teachers. Data were collected from 176 preservice teachers enrolled in a field-based teacher education program located at a major Southwestern university in the United…

THE APPLICATION OF IN SITU PERMEABLE REACTIVE (ZERO-VALENT IRON) BARRIER TECHNOLOGY FOR THE REMEDIATION OF CHROMATE-CONTAMINATED GROUNDWATER: A FIELD TEST

EPA Science Inventory

A small-scale field test was initiated in September 1994 to evaluate the in situ remediation of groundwater contaminated with chromate using a permeable reactive barrier composed of a mixture of zero-valent Fe, sand and aquifer sediment. The site used was an old chrome-plating f...

Understanding the free energy barrier and multiple timescale dynamics of charge separation in organic photovoltaic cells.

PubMed

Yan, Yaming; Song, Linze; Shi, Qiang

2018-02-28

By employing several lattice model systems, we investigate the free energy barrier and real-time dynamics of charge separation in organic photovoltaic (OPV) cells. It is found that the combined effects of the external electric field, entropy, and charge delocalization reduce the free energy barrier significantly. The dynamic disorder reduces charge carrier delocalization and results in the increased charge separation barrier, while the effect of static disorder is more complicated. Simulation of the real-time dynamics indicates that the free charge generation process involves multiple time scales, including an ultrafast component within hundreds of femtoseconds, an intermediate component related to the relaxation of the hot charge transfer (CT) state, and a slow component on the time scale of tens of picoseconds from the thermally equilibrated CT state. Effects of hot exciton dissociation as well as its dependence on the energy offset between the Frenkel exciton and the CT state are also analyzed. The current results indicate that only a small energy offset between the band gap and the lowest energy CT state is needed to achieve efficient free charge generation in OPV devices, which agrees with recent experimental findings.

Evaluation of the Osteoporosis Health Belief Scale in Korean Women

PubMed Central

Kim, Tae-Hee; Lee, Young-Sang; Byun, Dong Won; Jang, Seyeon; Jeon, Dong-Su

2013-01-01

Background The Osteoporosis Health Belief Scale (OHBS) is a 42-item questionnaire designed to assess susceptibility, seriousness, calcium benefits, calcium barriers, exercise benefits, exercise barriers, and health motivation related to osteoporosis. We aimed to evaluate its psychometric properties to enable the provision of educational tips regarding osteoporosis. Methods All women who had visited the department of obstetrics and gynecology (OBGYN) and whose bone mineral density was measured from January 2010 to December 2011 were enrolled by interview using the OHBS. We also evaluated the women's general clinical characteristics. Results One hundred seventy-seven women were enrolled in the present study. In the present study, the barriers to calcium intake subscale had the lowest mean score (15.03±3.02), and the Benefit of Exercise subscale had the highest (23.02±3.03). The scores for participants in their 20s were significantly higher than scores for those in their 70s on the Benefits of Exercise subscale and Barriers to Exercise subscale (P=0.014 and P=0.022, respectively). Conclusions Education for health motivation to prevent osteoporosis is important for young women. Additional systematic education programs are needed for the general population. PMID:24524052

Understanding the free energy barrier and multiple timescale dynamics of charge separation in organic photovoltaic cells

NASA Astrophysics Data System (ADS)

Yan, Yaming; Song, Linze; Shi, Qiang

2018-02-01

By employing several lattice model systems, we investigate the free energy barrier and real-time dynamics of charge separation in organic photovoltaic (OPV) cells. It is found that the combined effects of the external electric field, entropy, and charge delocalization reduce the free energy barrier significantly. The dynamic disorder reduces charge carrier delocalization and results in the increased charge separation barrier, while the effect of static disorder is more complicated. Simulation of the real-time dynamics indicates that the free charge generation process involves multiple time scales, including an ultrafast component within hundreds of femtoseconds, an intermediate component related to the relaxation of the hot charge transfer (CT) state, and a slow component on the time scale of tens of picoseconds from the thermally equilibrated CT state. Effects of hot exciton dissociation as well as its dependence on the energy offset between the Frenkel exciton and the CT state are also analyzed. The current results indicate that only a small energy offset between the band gap and the lowest energy CT state is needed to achieve efficient free charge generation in OPV devices, which agrees with recent experimental findings.

First-principles study of the effects of Silicon doping on the Schottky barrier of TiSi2/Si interfaces

NASA Astrophysics Data System (ADS)

Wang, Han; Silva, Eduardo; West, Damien; Sun, Yiyang; Restrepo, Oscar; Zhang, Shengbai; Kota, Murali

As scaling of semiconductor devices is pursued in order to improve power efficiency, quantum effects due to the reduced dimensions on devices have become dominant factors in power, performance, and area scaling. In particular, source/drain contact resistance has become a limiting factor in the overall device power efficiency and performance. As a consequence, techniques such as heavy doping of source and drain have been explored to reduce the contact resistance, thereby shrinking the width of depletion region and lowering the Schottky barrier height. In this work, we study the relation between doping in Silicon and the Schottky barrier of a TiSi2/Si interface with first-principles calculation. Virtual Crystal Approximation (VCA) is used to calculate the average potential of the interface with varying doping concentration, while the I-V curve for the corresponding interface is calculated with a generalized one-dimensional transfer matrix method. The relation between substitutional and interstitial Boron and Phosphorus dopant near the interface, and their effect on tuning the Schottky barrier is studied. These studies provide insight to the type of doping and the effect of dopant segregation to optimize metal-semiconductor interface resistance.

Facilitators and barriers in expanding scope of practice: findings from a national survey of Irish nurses and midwives.

PubMed

Fealy, Gerard M; Rohde, Daniela; Casey, Mary; Brady, Anne-Marie; Hegarty, Josephine; Kennedy, Catriona; McNamara, Martin; O'Reilly, Pauline; Prizeman, Geraldine

2015-12-01

The aim was to examine current scope of practice among nurses and midwives in Ireland. The objectives were to describe practitioners' self-reported facilitators and barriers to expanding scope of practice and to develop a scope of practice barriers scale. Regulatory authorities permit practice expansion, so long as it falls within accepted parameters of scope of practice. Enduring difficulties in relation to scope of practice include the difficulty of balancing practice restriction with practice expansion. A postal survey design was used to examine registered nurses' and midwives' current scope of practice, including their experiences of facilitators and barriers to expanding practice. A stratified random sample of registered nurses and midwives in Ireland was surveyed using the Scope-QB, a 19-item self-report scope of practice barriers scale. Based on a sample of 1010 respondents, the self-reported perceived barriers to practice expansion included fear of legal consequences, time restrictions and lack of remuneration. Professional satisfaction, patients' needs, organisational support and having access to continuing professional education were perceived as facilitators of practice expansion. Older nurses and midwives as well as nurses and midwives holding more senior promotional grades, such as clinical nurse manager grades, perceived fewer barriers than their younger and more junior counterparts. Nurses and midwives continue to experience difficulties in relation to expanding their practice. Practitioners can operate to optimal scope of practice when practitioner-centred and workplace-based circumstances are optimal. The optimal circumstances for practice expansion exist when the facilitators of practice expansion outweigh the barriers. Given the critical role that nurses and midwives play in modern health services, it is important that they are empowered and enabled to expand their practice and to work to full scope of practice when patient needs and service requirements warrant it. © 2015 John Wiley & Sons Ltd.

Barriers to exercise in younger and older non-exercising adult women: a cross sectional study in London, United Kingdom.

PubMed

El Ansari, Walid; Lovell, Geoff

2009-04-01

A survey of 100 women in the south of London, United Kingdom (UK) compared exercise barrier intensities between non-exercising younger (20-27 years) and older (28-35 years) adult women; and examined childcare duties as perceived barriers to exercise. Perceived barriers to exercise were examined using an Exercise Benefits/Barriers Scale (EBBS) comprising four subscales (exercise milieu; time expenditure; physical exertion; family discouragement). Participants' number of children was also noted. Non-exercising older women reported significantly higher total exercise barriers, as well as across three barrier subscales: exercise milieu, time expenditure, and family discouragement. For both age groups, significant correlation existed between number of children and women's total exercise barrier scores. Number of children explained approximately 25% and approximately 30% of the variance of younger and older women's total barrier scores respectively. For both women groups, the strongest correlation between exercise barrier and number of children was for the time expenditure subscale. Broad grouping of 20-35 year old non-exercising women does not reflect a homogenous sample. Age categories employing narrower age brackets are recommended. Issues surrounding family responsibilities e.g. childcare duties may be shared between these groups and require further research and policy attention.

Barriers to Exercise in Younger and Older Non-Exercising Adult Women: A Cross Sectional Study in London, United Kingdom

PubMed Central

Ansari, Walid El; Lovell, Geoff

2009-01-01

A survey of 100 women in the south of London, United Kingdom (UK) compared exercise barrier intensities between non-exercising younger (20–27 years) and older (28–35 years) adult women; and examined childcare duties as perceived barriers to exercise. Perceived barriers to exercise were examined using an Exercise Benefits/Barriers Scale (EBBS) comprising four subscales (exercise milieu; time expenditure; physical exertion; family discouragement). Participants’ number of children was also noted. Non-exercising older women reported significantly higher total exercise barriers, as well as across three barrier subscales: exercise milieu, time expenditure, and family discouragement. For both age groups, significant correlation existed between number of children and women’s total exercise barrier scores. Number of children explained ≈25% and ≈30% of the variance of younger and older women’s total barrier scores respectively. For both women groups, the strongest correlation between exercise barrier and number of children was for the time expenditure subscale. Broad grouping of 20–35 year old non-exercising women does not reflect a homogenous sample. Age categories employing narrower age brackets are recommended. Issues surrounding family responsibilities e.g. childcare duties may be shared between these groups and require further research and policy attention. PMID:19440527

A randomized control hands-on defibrillation study-Barrier use evaluation.

PubMed

Wampler, David; Kharod, Chetan; Bolleter, Scotty; Burkett, Alison; Gabehart, Caitlin; Manifold, Craig

2016-06-01

Chest compressions and defibrillation are the only therapies proven to increase survival in cardiac arrest. Historically, rescuers must remove hands to shock, thereby interrupting chest compressions. This hands-off time results in a zero blood flow state. Pauses have been associated with poorer neurological recovery. This was a blinded randomized control cadaver study evaluating the detection of defibrillation during manual chest compressions. An active defibrillator was connected to the cadaver in the sternum-apex configuration. The sham defibrillator was not connected to the cadaver. Subjects performed chest compressions using 6 barrier types: barehand, single and double layer nitrile gloves, firefighter gloves, neoprene pad, and a manual chest compression/decompression device. Randomized defibrillations (10 per barrier type) were delivered at 30 joules (J) for bare hand and 360J for all other barriers. After each shock, the subject indicated degree of sensation on a VAS scale. Ten subjects participated. All subjects detected 30j shocks during barehand compressions, with only 1 undetected real shock. All barriers combined totaled 500 shocks delivered. Five (1%) active shocks were detected, 1(0.2%) single layer of Nitrile, 3(0.6%) with double layer nitrile, and 1(0.2%) with the neoprene barrier. One sham shock was reported with the single layer nitrile glove. No shocks were detected with fire gloves or compression decompression device. All shocks detected barely perceptible (0.25(±0.05)cm on 10cm VAS scale). Nitrile gloves and neoprene pad prevent (99%) responder's detection of defibrillation of a cadaver. Fire gloves and compression decompression device prevented detection. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

When Might Barrier Island Chains 'Collapse'? An Initial Model Investigation

NASA Astrophysics Data System (ADS)

Slott, J. M.; Murray, A. B.

2007-12-01

There has been recent speculation that, in response to the accelerated sea-level rise and intensified storms expected over the coming century, barrier island chains such as those found on the US Atlantic and Gulf coastlines, could develop large (10-kilometer-scale) gaps in their most narrow stretches, or might disappear completely (Riggs, S. R., 2001). Such a collapse along the North Carolina Outer Banks barrier island chain, for example, would leave the mainland vulnerable to direct hits from Western Atlantic storm systems, and also would dramatically alter the estuarine system it encloses with potentially devastating effects to marine life. Concern for the future of the Outer Banks is also motivated by the decimation of the Chandeleur Islands in 2005 from Hurricane Katrina. We will present a series of initial numerical modeling experiments addressing how barrier island morphodynamics respond to the sudden creation of kilometer-scale gaps. Large-scale barrier island evolution is influenced by sea-level rise and barrier island overwash, alongshore sediment transport, tidal currents, and the availability of mobile sediment. Barrier islands transgress towards the mainland in response to sea-level rise through overwash: ocean-facing shorelines provide sediment that is transported onto the island to maintain its subaerial height and behind the island to maintain its width, while gradients in alongshore sediment transport typically dictate the large-scale shape of a coastline over long time frames (decades to millenia). Tidal currents also tend to scour inlet channels; the relative strength of this effect depends in part upon the width of the inlet channel. Our exploratory model includes both a one-line alongshore transport component and a cross-shore overwash component, as well as representations of underlying geology (weathering rates and material compositions). In our modeling experiments, we test the effects of perforating a 30 km barrier island chain with variable-sized gaps, ranging between 2.5-10 km. In preliminary model experiments, where we do not limit the availability of mobile sediment nor include tidal inlet dynamics, large gaps tend to close under all of the erosion rate scenarios and gap sizes. The ends of barrier islands extend to fill in the gaps and recurve landward. The rate of closure of gaps is unaffected by sea-level rise rates even under the most extreme cases; alongshore sediment fluxes exceed those associated with sea-level rise as highly curved isolated islands migrate rapidly landward before coalescing into an island chain again at a new location. In a natural setting, the overwash and spit-growth that maintain sub-aerial islands and tend to knit them back together (respectively) could be inhibited by a lack of mobile sediment. The shoreface of the Outer Banks, for example, consists of sometimes patchy Holocene sands perched atop a semi-lithified, sometimes more muddy Pleistocene substrate. Weathering of the Pleistocene substrate over long timescales generates mobile sediment consisting of both sands and muds. The fine-grained material, however, is typically lost to the nearshore system. The shoreface may not be able to weather fast enough to keep up with rapidly migrating islands. This effect, combined with that of substrate composition, will tend to limit the rate that sediment can be liberated, and, in turn, could prevent island-chain recovery. We conduct a series of model experiments to determine the combinations of geological parameters (weathering rates, composition) and forcing parameters (rate of sea-level rise, frequency of storms) that prevent barrier-island-chain recovery.

Multi-scale Modeling in Clinical Oncology: Opportunities and Barriers to Success.

PubMed

Yankeelov, Thomas E; An, Gary; Saut, Oliver; Luebeck, E Georg; Popel, Aleksander S; Ribba, Benjamin; Vicini, Paolo; Zhou, Xiaobo; Weis, Jared A; Ye, Kaiming; Genin, Guy M

2016-09-01

Hierarchical processes spanning several orders of magnitude of both space and time underlie nearly all cancers. Multi-scale statistical, mathematical, and computational modeling methods are central to designing, implementing and assessing treatment strategies that account for these hierarchies. The basic science underlying these modeling efforts is maturing into a new discipline that is close to influencing and facilitating clinical successes. The purpose of this review is to capture the state-of-the-art as well as the key barriers to success for multi-scale modeling in clinical oncology. We begin with a summary of the long-envisioned promise of multi-scale modeling in clinical oncology, including the synthesis of disparate data types into models that reveal underlying mechanisms and allow for experimental testing of hypotheses. We then evaluate the mathematical techniques employed most widely and present several examples illustrating their application as well as the current gap between pre-clinical and clinical applications. We conclude with a discussion of what we view to be the key challenges and opportunities for multi-scale modeling in clinical oncology.

Utilization of Large Scale Surface Models for Detailed Visibility Analyses

NASA Astrophysics Data System (ADS)

Caha, J.; Kačmařík, M.

2017-11-01

This article demonstrates utilization of large scale surface models with small spatial resolution and high accuracy, acquired from Unmanned Aerial Vehicle scanning, for visibility analyses. The importance of large scale data for visibility analyses on the local scale, where the detail of the surface model is the most defining factor, is described. The focus is not only the classic Boolean visibility, that is usually determined within GIS, but also on so called extended viewsheds that aims to provide more information about visibility. The case study with examples of visibility analyses was performed on river Opava, near the Ostrava city (Czech Republic). The multiple Boolean viewshed analysis and global horizon viewshed were calculated to determine most prominent features and visibility barriers of the surface. Besides that, the extended viewshed showing angle difference above the local horizon, which describes angular height of the target area above the barrier, is shown. The case study proved that large scale models are appropriate data source for visibility analyses on local level. The discussion summarizes possible future applications and further development directions of visibility analyses.

Multi-scale Modeling in Clinical Oncology: Opportunities and Barriers to Success

PubMed Central

Yankeelov, Thomas E.; An, Gary; Saut, Oliver; Luebeck, E. Georg; Popel, Aleksander S.; Ribba, Benjamin; Vicini, Paolo; Zhou, Xiaobo; Weis, Jared A.; Ye, Kaiming; Genin, Guy M.

2016-01-01

Hierarchical processes spanning several orders of magnitude of both space and time underlie nearly all cancers. Multi-scale statistical, mathematical, and computational modeling methods are central to designing, implementing and assessing treatment strategies that account for these hierarchies. The basic science underlying these modeling efforts is maturing into a new discipline that is close to influencing and facilitating clinical successes. The purpose of this review is to capture the state-of-the-art as well as the key barriers to success for multi-scale modeling in clinical oncology. We begin with a summary of the long-envisioned promise of multi-scale modeling in clinical oncology, including the synthesis of disparate data types into models that reveal underlying mechanisms and allow for experimental testing of hypotheses. We then evaluate the mathematical techniques employed most widely and present several examples illustrating their application as well as the current gap between pre-clinical and clinical applications. We conclude with a discussion of what we view to be the key challenges and opportunities for multi-scale modeling in clinical oncology. PMID:27384942

Career Adapt-Abilities Scale--Italian Form: Psychometric Properties and Relationships to Breadth of Interests, Quality of Life, and Perceived Barriers

ERIC Educational Resources Information Center

Soresi, Salvatore; Nota, Laura; Ferrari, Lea

2012-01-01

The Career Adapt-Abilities Scale (CAAS)-Italian Form consists of four 6-item scales, which measure concern, control, curiosity, and confidence as psychosocial resources for managing occupational transitions, developmental tasks, and work traumas. The 24-item CAAS-Italian Form is identical to the International Form 2.0. The factor structure was…

System-Level Action Required for Wide-Scale Improvement in Quality of Primary Health Care: Synthesis of Feedback from an Interactive Process to Promote Dissemination and Use of Aggregated Quality of Care Data.

PubMed

Bailie, Jodie; Laycock, Alison; Matthews, Veronica; Bailie, Ross

2016-01-01

There is an enduring gap between recommended practice and care that is actually delivered; and there is wide variation between primary health care (PHC) centers in delivery of care. Where aspects of care are not being done well across a range of PHC centers, this is likely due to inadequacies in the broader system. This paper aims to describe stakeholders' perceptions of the barriers and enablers to addressing gaps in Australian Aboriginal and Torres Strait Islander chronic illness care and child health, and to identify key drivers for improvement. This paper draws on data collected as part of a large-scale continuous quality improvement project in Australian Indigenous PHC settings. We undertook a qualitative assessment of stakeholder feedback on the main barriers and enablers to addressing gaps in care for Aboriginal and Torres Strait Islander children and in chronic illness care. Themes on barriers and enablers were further analyzed to develop a "driver diagram," an improvement tool used to locate barriers and enablers within causal pathways (as primary and secondary drivers), enabling them to be targeted by tailored interventions. We identified 5 primary drivers and 11 secondary drivers of high-quality care, and associated strategies that have potential for wide-scale implementation to address barriers and enablers for improving care. Perceived barriers to addressing gaps in care included both health system and staff attributes. Primary drivers were: staff capability to deliver high-quality care; availability and use of clinical information systems and decision support tools; embedding of quality improvement processes and data-driven decision-making; appropriate and effective recruitment and retention of staff; and community capacity, engagement and mobilization for health. Suggested strategies included mechanisms for increasing clinical supervision and support, staff retention, reorientation of service delivery, use of information systems and community health literacy. The findings identify areas of focus for development of barrier-driven, tailored interventions to improve health outcomes. They reinforce the importance of system-level action to improve health center performance and health outcomes, and of developing strategies to address system-wide challenges that can be adapted to local contexts.

Super Oxygen and Improved Water Vapor Barrier of Polypropylene Film with Polyelectrolyte Multilayer Nanocoatings.

PubMed

Song, Yixuan; Tzeng, Ping; Grunlan, Jaime C

2016-06-01

Biaxially oriented polypropylene (BOPP) is widely used in packaging. Although its orientation increases mechanical strength and clarity, BOPP suffers from a high oxygen transmission rate (OTR). Multilayer thin films are deposited from water using layer-by-layer (LbL) assembly. Polyethylenimine (PEI) is combined with either poly(acrylic acid) (PAA) or vermiculite (VMT) clay to impart high oxygen barrier. A 30-bilayer PEI/VMT nanocoating (226 nm thick) improves the OTR of 17.8 μm thick BOPP by more than 30X, rivaling most inorganic coatings. PEI/PAA multilayers achieve comparable barrier with only 12 bilayers due to greater thickness, but these films exhibit increased oxygen permeability at high humidity. The PEI/VMT coatings actually exhibit improved oxygen barrier at high humidity (and also improve moisture barrier by more than 40%). This high barrier BOPP meets the criteria for sensitive food and some electronics packaging applications. Additionally, this water-based coating technology is cost effective and provides an opportunity to produce high barrier polypropylene film on an industrial scale. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Methods for fabricating a micro heat barrier

DOEpatents

Marshall, Albert C.; Kravitz, Stanley H.; Tigges, Chris P.; Vawter, Gregory A.

2004-01-06

Methods for fabricating a highly effective, micron-scale micro heat barrier structure and process for manufacturing a micro heat barrier based on semiconductor and/or MEMS fabrication techniques. The micro heat barrier has an array of non-metallic, freestanding microsupports with a height less than 100 microns, attached to a substrate. An infrared reflective membrane (e.g., 1 micron gold) can be supported by the array of microsupports to provide radiation shielding. The micro heat barrier can be evacuated to eliminate gas phase heat conduction and convection. Semi-isotropic, reactive ion plasma etching can be used to create a microspike having a cusp-like shape with a sharp, pointed tip (<0.1 micron), to minimize the tip's contact area. A heat source can be placed directly on the microspikes. The micro heat barrier can have an apparent thermal conductivity in the range of 10.sup.-6 to 10.sup.-7 W/m-K. Multiple layers of reflective membranes can be used to increase thermal resistance.

Informing watershed connectivity barrier prioritization decisions: A synthesis

USGS Publications Warehouse

McKay, S. K.; Cooper, A. R.; Diebel, M.W.; Elkins, D.; Oldford, G.; Roghair, C.; Wieferich, Daniel J.

2017-01-01

Water resources and transportation infrastructure such as dams and culverts provide countless socio-economic benefits; however, this infrastructure can also disconnect the movement of organisms, sediment, and water through river ecosystems. Trade-offs associated with these competing costs and benefits occur globally, with applications in barrier addition (e.g. dam and road construction), reengineering (e.g. culvert repair), and removal (e.g. dam removal and aging infrastructure). Barrier prioritization provides a unique opportunity to: (i) restore and reconnect potentially large habitat patches quickly and effectively and (ii) avoid impacts prior to occurrence in line with the mitigation hierarchy (i.e. avoid then minimize then mitigate). This paper synthesizes 46 watershed-scale barrier planning studies and presents a procedure to guide barrier prioritization associated with connectivity for aquatic organisms. We focus on practical issues informing prioritization studies such as available data sets, methods, techniques, and tools. We conclude with a discussion of emerging trends and issues in barrier prioritization and key opportunities for enhancing the body of knowledge.

Use of lignocellulosic materials as sorbents for pesticide and phosphate residues

Treesearch

Mandla A. Tshabalala

2006-01-01

We previously reported results from limited field trials of a bark-based filtration unit designed to remove phosphorus from cranberry bog tail water. In that report we also identified some barriers that needed to be overcome to improve the performance of such a filtration unit. One barrier was lack of a cost effective process for large-scale conversion of bark to an...

Stacked Metal Silicide/Silicon Far-Infrared Detectors

NASA Technical Reports Server (NTRS)

Maserjian, Joseph

1988-01-01

Selective doping of silicon in proposed metal silicide/silicon Schottky-barrier infrared photodetector increases maximum detectable wavelength. Stacking layers to form multiple Schottky barriers increases quantum efficiency of detector. Detectors of new type enhance capabilities of far-infrared imaging arrays. Grows by molecular-beam epitaxy on silicon waferscontaining very-large-scale integrated circuits. Imaging arrays of detectors made in monolithic units with image-preprocessing circuitry.

PILOT-SCALE EVALUATION OF ENGINEERED BARIER SYSTEMS FOR THE YUCCA MOUNTAIN PROJECT

DOE Office of Scientific and Technical Information (OSTI.GOV)

S.W. Webb; J.T. George; R.E. Finley

This paper describes two quarter-scale experiments (1.4 m diameter) and associated numerical analyses on granular backfill engineered barrier systems in support of the Yucca Mountain Project for the potential repository. The two configurations include a sloped capillary barrier and a plain backfill. The tests involve application of dyed water as a constant line infiltration source along the top of the test set-up, monitoring water movement through the test, and measuring water exiting the experiments. A complete water balance estimate is made for each test, and observed water movement is compared with (1) detailed numerical analyses conducted using the TOUGH2 codemore » for unsaturated flow in porous media and (2) posttest observations. The results of the testing and analyses show that for the injection rates and configuration applied, the capillary barrier design diverts a significant amount of all injected water and the TOUGH2 pretest predictions show qualitative and quantitative agreement with the experimental data.« less

Barriers to primary care hospital follow-up among older adults in rural or semi-rural communities.

PubMed

Hardman, Bobbi; Newcomb, Patricia

2016-02-01

Failure to follow-up with a primary care provider (PCP) following discharge from an acute care setting is strongly associated with readmission within 90 days among elderly patients. The purpose of this study was to identify barriers to primary care follow-up among older adults in rural communities. This was an explanatory mixed methods study which included scaled survey and interview techniques. Descriptive and inferential statistics were calculated for scaled concepts. Standard content analysis was performed on the qualitative items. Correlation between intention to follow-up with a PCP and actual follow-up was poor (r=0.20). Patients encountered substantial obstacles to the PCP follow-up visit. Obstacles clustered into two groups: 1) healthcare or social system barriers and 2) personal characteristics of patients. Individualized discharge planning that reflects the complexities of post-hospitalization adaptation for elders is most likely to be useful for ensuring PCP follow-up. Copyright © 2015 Elsevier Inc. All rights reserved.

Microfibrillated cellulose - its barrier properties and applications in cellulosic materials: a review.

PubMed

Lavoine, Nathalie; Desloges, Isabelle; Dufresne, Alain; Bras, Julien

2012-10-01

Interest in microfibrillated cellulose (MFC) has been increasing exponentially. During the last decade, this bio-based nanomaterial was essentially used in nanocomposites for its reinforcement property. Its nano-scale dimensions and its ability to form a strong entangled nanoporous network, however, have encouraged the emergence of new high-value applications. In previous years, its mode of production has completely changed, as many forms of optimization have been developed. New sources, new mechanical processes, and new pre- and post-treatments are currently under development to reduce the high energy consumption and produce new types of MFC materials on an industrial scale. The nanoscale characterization possibilities of different MFC materials are thus increasing intensively. Therefore, it is critical to review such MFC materials and their properties. Moreover, very recent studies have proved the significant barrier properties of MFC. Hence, it is proposed to focus on the barrier properties of MFC used in films, in nanocomposites, or in paper coating. Copyright © 2012 Elsevier Ltd. All rights reserved.

Barriers to Seeking Help for Skin Cancer Detection in Rural Australia

PubMed Central

Fennell, Kate M.; Martin, Kimberley; Wilson, Carlene J.; Trenerry, Camilla; Sharplin, Greg; Dollman, James

2017-01-01

This study explores rural South Australians’ barriers to help-seeking for skin cancer detection. A total of 201 randomly selected rural adults (18–94 years, 66% female) were presented with a skin-cancer-related scenario via telephone and were asked the extent to which various barriers would impede their help-seeking, based on an amended version of the Barriers to Help-Seeking Scale. Older (≥63 years) and less educated participants endorsed barriers more strongly than their younger, more educated counterparts in the following domains; “Concrete barriers and distrust of caregivers”, “Emotional control”, “Minimising problem and Normalisation”, “Need for control and self-reliance” (every domain other than “Privacy”). Socioeconomic disadvantage, gender, and farmer status did not predict stronger overall barriers, but some gender and occupation-related differences were detected at the item level. Farmers were also more likely to endorse the “Minimising problem and normalization” domain than their non-farmer working rural counterparts. Widely endorsed barriers included the tendency to minimise the problem, a desire to remain in control/not be influenced by others, reluctance to show emotion or complain, and having concerns about privacy or waiting times. PMID:28208803

Social, ethical and legal barriers to e-health.

PubMed

Anderson, James G

2007-01-01

Information technology such as electronic medical records (EMRs), electronic prescribing and decision support systems are recognized as essential tools in Europe, the U.S., Canada, Australia, and New Zealand. But significant barriers impede wide-scale adoption of these tools, especially EMR systems. The objectives of this study were to investigate the present status of information technology in health care, the perceived benefits and barriers by primary care physicians. Literature analysis and survey data from primary care physicians on adoption of information technology are reviewed. The U.S. trails European countries as well as Canada, Australia and New Zealand in the use of information technology in primary care. The results of the study indicate that physicians in general perceive benefits to information technology, but also cite major barriers to its implementation in their practices. These barriers include lack of access to capital by health care providers, complex systems and lack of data standards that permit exchange of clinical data, privacy concerns and legal barriers. Overcoming these barriers will require subsidies and performance incentives by payers and government; certification and standardization of vendor applications that permit clinical data exchange; removal of legal barriers; and greater security of medical data to convince practitioners and patients of the value of EMRs.

Congruent biogeographical disjunctions at a continent-wide scale: Quantifying and clarifying the role of biogeographic barriers in the Australian tropics

PubMed Central

Crisp, Michael D.; Cook, Dianne H.; Cook, Lyn G.

2017-01-01

Aim To test whether novel and previously hypothesized biogeogaphic barriers in the Australian Tropics represent significant disjunction points or hard barriers, or both, to the distribution of plants. Location Australian tropics: Australian Monsoon Tropics and Australian Wet Tropics. Methods The presence or absence of 6,861 plant species was scored across 13 putative biogeographic barriers in the Australian Tropics, including two that have not previously been recognised. Randomizations of these data were used to test whether more species showed disjunctions (gaps in distribution) or likely barriers (range limits) at these points than expected by chance. Results Two novel disjunctions in the Australian Tropics flora are identified in addition to eleven putative barriers previously recognized for animals. Of these, eleven disjunction points (all within the Australian Monsoon Tropics) were found to correspond to range-ending barriers to a significant number of species, while neither of the two disjunctions found within the Australian Wet Tropics limited a significant number of species’ ranges. Main conclusions Biogeographic barriers present significant distributional limits to native plant species in the Australian Monsoon Tropics but not in the Australian Wet Tropics. PMID:28376094

Governance and sustainability at a municipal scale: the challenge of water conservation.

PubMed

Furlong, Kathryn; Bakker, Karen

2011-01-01

Municipal water conservation is increasingly promoted as a key dimension of environmental sustainability at the municipal scale. Progress toward municipal water conservation in Canada has, however, been poor. This paper examines the governance dimension of water conservation, and presents evidence in support of the argument that conservation efforts on the part of water utilities (and sometimes municipalities) are often constrained by factors external to their jurisdiction. To explore these issues, this paper presents a case study of municipal water conservation in Canada. The analysis identifies governance-related barriers to water conservation and explores the relationship between these barriers and broader issues stemming from the multi-scalar, fragmented nature of environmental governance in Canada.

Adaptation and testing of instruments to measure cervical cancer screening factors among Vietnamese immigrant women.

PubMed

Nguyen-Truong, Connie K Y; Leo, Michael C; Lee-Lin, Frances; Gedaly-Duff, Vivian; Nail, Lillian M; Gregg, Jessica; Le, Tuong Vy; Tran, Tuyen

2015-05-01

Vietnamese American women diagnosed with cervical cancer are more likely to have advanced cancer than non-Hispanic White women. We sought to (a) develop a culturally sensitive Vietnamese translation of the Revised Susceptibility, Benefits, and Barriers Scale; Cultural Barriers to Screening Inventory; Confidentiality Issues Scale; and Quality of Care from the Health Care System Scale and (b) examine the psychometric properties. Cross-sectional study with 201 Vietnamese immigrant women from the Portland, Oregon, metropolitan area. We used a community-based participatory research approach and the U.S. Census Bureau's team approach to translation. Cronbach's alpha ranged from .57 to .91. The incremental fit index ranged from .83 to .88. The instruments demonstrated moderate to strong subscale internal consistency. Further research to assess structural validity is needed. Our approaches to translation and psychometric examination support use of the instruments in Vietnamese immigrant women. © The Author(s) 2014.

Thin film growth studies using time-resolved x-ray scattering

NASA Astrophysics Data System (ADS)

Kowarik, Stefan

2017-02-01

Thin-film growth is important for novel functional materials and new generations of devices. The non-equilibrium growth physics involved is very challenging, because the energy landscape for atomic scale processes is determined by many parameters, such as the diffusion and Ehrlich-Schwoebel barriers. We review the in situ real-time techniques of x-ray diffraction (XRD), x-ray growth oscillations and diffuse x-ray scattering (GISAXS) for the determination of structure and morphology on length scales from Å to µm. We give examples of time resolved growth experiments mainly from molecular thin film growth, but also highlight growth of inorganic materials using molecular beam epitaxy (MBE) and electrochemical deposition from liquids. We discuss how scaling parameters of rate equation models and fundamental energy barriers in kinetic Monte Carlo methods can be determined from fits of the real-time x-ray data.

Thin film growth studies using time-resolved x-ray scattering.

PubMed

Kowarik, Stefan

2017-02-01

Thin-film growth is important for novel functional materials and new generations of devices. The non-equilibrium growth physics involved is very challenging, because the energy landscape for atomic scale processes is determined by many parameters, such as the diffusion and Ehrlich-Schwoebel barriers. We review the in situ real-time techniques of x-ray diffraction (XRD), x-ray growth oscillations and diffuse x-ray scattering (GISAXS) for the determination of structure and morphology on length scales from Å to µm. We give examples of time resolved growth experiments mainly from molecular thin film growth, but also highlight growth of inorganic materials using molecular beam epitaxy (MBE) and electrochemical deposition from liquids. We discuss how scaling parameters of rate equation models and fundamental energy barriers in kinetic Monte Carlo methods can be determined from fits of the real-time x-ray data.

Entropic Barriers for Two-Dimensional Quantum Memories

NASA Astrophysics Data System (ADS)

Brown, Benjamin J.; Al-Shimary, Abbas; Pachos, Jiannis K.

2014-03-01

Comprehensive no-go theorems show that information encoded over local two-dimensional topologically ordered systems cannot support macroscopic energy barriers, and hence will not maintain stable quantum information at finite temperatures for macroscopic time scales. However, it is still well motivated to study low-dimensional quantum memories due to their experimental amenability. Here we introduce a grid of defect lines to Kitaev's quantum double model where different anyonic excitations carry different masses. This setting produces a complex energy landscape which entropically suppresses the diffusion of excitations that cause logical errors. We show numerically that entropically suppressed errors give rise to superexponential inverse temperature scaling and polynomial system size scaling for small system sizes over a low-temperature regime. Curiously, these entropic effects are not present below a certain low temperature. We show that we can vary the system to modify this bound and potentially extend the described effects to zero temperature.

Expanding mental health services through novel models of intervention delivery.

PubMed

Kazdin, Alan E

2018-06-13

Currently, in the United States and worldwide, the vast majority of children and adolescents in need of mental health services receive no treatment. Although there are many barriers, a key barrier is the dominant model of delivering psychosocial interventions. That model includes one-to-one, in-person treatment, with a trained mental health professional, provided in clinical setting (e.g., clinic, private practice office, health-care facility). That model greatly limits the scale and reach of psychosocial interventions. The article discusses many novel models of delivering interventions that permit scaling treatment to encompass children and adolescents who are not likely to receive services. Special attention is accorded the use of social media, socially assistive robots, and social networks that not only convey the ability to scale interventions but also encompass interventions that depart from the usual forms of intervention that currently dominate psychosocial treatment research. © 2018 Association for Child and Adolescent Mental Health.

Shyness and Love on a College Campus.

ERIC Educational Resources Information Center

Maroldo, Georgette K.

1982-01-01

Shyness and love scales were administered to 153 men and 217 women at Texas Lutheran College. Love, dating, and friendship groups were identified on the love scale with respect, congeniality, altruism, physical attraction, and attachment subscales. For the love and friendship groups, shyness appears to be a barrier. (Author/CM)

Psychometric Evaluation of Three Psychosocial Measures Associated with Physical Activity among Adolescent Girls

ERIC Educational Resources Information Center

Ling, Jiying; Robbins, Lorraine B.

2017-01-01

The purpose of this study was to evaluate the psychometric properties of a Perceived Benefits Scale, a Perceived Barriers Scale, and a Physical Activity Enjoyment Scale with data from a group randomized controlled trial (RCT) and a test-retest study with 1-week interval. In the group RCT at baseline and Week 17, 1,012 fifth- to eighth-grade girls…

Stages of condom use and decisional balance among college students.

PubMed

Tung, W-C; Farmer, S; Ding, K; Tung, W-K; Hsu, C-H

2009-09-01

To explore sexual behaviours and condom use and differences in specific items of perceived benefits and barriers to condoms using the Transtheoretical Model (TTM) stages among college students in southern Taiwan. The TTM suggests that individuals in the action or maintenance stage exhibit higher levels of perceived benefits and lower levels of perceived barriers related to condom use than people in the precontemplation, contemplation or preparation stage. This was a descriptive, cross-sectional design with cluster sampling among college students from two universities in southern Taiwan. Participants completed self-administered questionnaires, including demographic data, Sexual History and Condom Use Scale and Condom Use Decisional Balance Scale. Of the 279 participants, 57% were sexually active, of these only 11.9% used condoms consistently. Respondents in the TTM stage of action/maintenance perceived greater benefits in relation to feeling more responsible (P = 0.031) and protecting their partners as well as themselves (P = 0.028), and perceived more barriers in believing that using condom needs to rely on partner's cooperation (P = 0.046) than participants in precontemplation. Participants in precontemplation and contemplation perceived more barriers related to worry about making their partner angry if condoms were used than those in action/maintenance (P = 0.008). Low levels of condom use among Taiwanese college students remain a significant public health concern. HIV prevention programmes for college students in Taiwan may be enhanced if they incorporate readiness to change and perceived benefits and barriers. Future research should include a larger sample with diverse groups.

Barrier breakdown mechanism in nano-scale perpendicular magnetic tunnel junctions with ultrathin MgO barrier

NASA Astrophysics Data System (ADS)

Lv, Hua; Leitao, Diana C.; Hou, Zhiwei; Freitas, Paulo P.; Cardoso, Susana; Kämpfe, Thomas; Müller, Johannes; Langer, Juergen; Wrona, Jerzy

2018-05-01

Recently, the perpendicular magnetic tunnel junctions (p-MTJs) arouse great interest because of its unique features in the application of spin-transfer-torque magnetoresistive random access memory (STT-MRAM), such as low switching current density, good thermal stability and high access speed. In this paper, we investigated current induced switching (CIS) in ultrathin MgO barrier p-MTJs with dimension down to 50 nm. We obtained a CIS perpendicular tunnel magnetoresistance (p-TMR) of 123.9% and 7.0 Ω.μm2 resistance area product (RA) with a critical switching density of 1.4×1010 A/m2 in a 300 nm diameter junction. We observe that the extrinsic breakdown mechanism dominates, since the resistance of our p-MTJs decreases gradually with the increasing current. From the statistical analysis of differently sized p-MTJs, we observe that the breakdown voltage (Vb) of 1.4 V is 2 times the switching voltage (Vs) of 0.7 V and the breakdown process exhibits two different breakdown states, unsteady and steady state. Using Simmons' model, we find that the steady state is related with the barrier height of the MgO layer. Furthermore, our study suggests a more efficient method to evaluate the MTJ stability under high bias rather than measuring Vb. In conclusion, we developed well performant p-MTJs for the use in STT-MRAM and demonstrate the mechanism and control of breakdown in nano-scale ultrathin MgO barrier p-MTJs.

Barrier Effect of the Indo-Pacific Maritime Continent on the MJO

NASA Astrophysics Data System (ADS)

Ling, Jian; Zhang, Chidong

2017-04-01

Explanations for the barrier effect of the Indo-Pacific Maritime Continent (MC) on the MJO should satisfy two criteria. First, they should include specific features of the MC, namely, its intricate land-sea distributions and elevated terrains. Second, they should include mechanisms for both the barrier effect and its overcoming by some MJO events. Guided by these two criteria, we applied a precipitation-tracking method to identify MJO events that propagate across the MC (MJO-C) and those that are blocked by the MC (MJO-B). About a half of MJO events that form over the Indian Ocean propagate through the MC. Most of them (> 75%) become weakened over the MC. The barrier effect cannot be explained in terms of the strength, horizontal scale, or spatial distribution of MJO convection when it approaches the MC from the west. A distinction between MJO-B and MJO-C is their precipitation over the sea vs. land in the MC region. MJO-C events rain more over the sea than over land, whereas land rainfall dominates for MJO-B. This suggests that inhibiting convective development over the sea could be a possible mechanism for the barrier effect of the MC. Preceding conditions for MJO-C include stronger low-level zonal moisture flux convergence and higher SST higher in the MC region. Possible connections between these large-scale conditions and the land vs. sea distributions of MJO rainfall through the diurnal cycle are discussed.

Enhancing ecosystem restoration efficiency through spatial and temporal coordination.

PubMed

Neeson, Thomas M; Ferris, Michael C; Diebel, Matthew W; Doran, Patrick J; O'Hanley, Jesse R; McIntyre, Peter B

2015-05-12

In many large ecosystems, conservation projects are selected by a diverse set of actors operating independently at spatial scales ranging from local to international. Although small-scale decision making can leverage local expert knowledge, it also may be an inefficient means of achieving large-scale objectives if piecemeal efforts are poorly coordinated. Here, we assess the value of coordinating efforts in both space and time to maximize the restoration of aquatic ecosystem connectivity. Habitat fragmentation is a leading driver of declining biodiversity and ecosystem services in rivers worldwide, and we simultaneously evaluate optimal barrier removal strategies for 661 tributary rivers of the Laurentian Great Lakes, which are fragmented by at least 6,692 dams and 232,068 road crossings. We find that coordinating barrier removals across the entire basin is nine times more efficient at reconnecting fish to headwater breeding grounds than optimizing independently for each watershed. Similarly, a one-time pulse of restoration investment is up to 10 times more efficient than annual allocations totaling the same amount. Despite widespread emphasis on dams as key barriers in river networks, improving road culvert passability is also essential for efficiently restoring connectivity to the Great Lakes. Our results highlight the dramatic economic and ecological advantages of coordinating efforts in both space and time during restoration of large ecosystems.

Health and wellness characteristics of persons with traumatic brain injury.

PubMed

Braden, Cynthia A; Cuthbert, Jeffrey P; Brenner, Lisa; Hawley, Lenore; Morey, Clare; Newman, Jody; Staniszewski, Kristi; Harrison-Felix, Cynthia

2012-01-01

To describe health and wellness characteristics of persons with TBI living in the community, compare to other disability populations and evaluate the associations between health-related constructs. Observational. Outpatient rehabilitation hospital and a Veterans Affairs Medical Centre. Seventy-four community-dwelling adults with moderate-to-severe TBI. None. Health Promoting Lifestyle Profile II (HPLP-II), Self Rated Abilities Health Practices Scale (SRAHP), Barriers to Health Promoting Activities for Disabled Scale (BHPAD), Medical Outcomes Study 12-Item Health Status Survey Short Form (SF-12), Personal Resource Questionnaire-adapted (PRQ-a), Perceived Wellness Survey (PWS), Diener Satisfaction with Life Scale (SWLS) and Participation Assessment with Recombined Tools-Objective (PART-O). Health-promoting behaviours, self-efficacy and barriers to health were comparable to other disability populations. Perceived health status, participation and life satisfaction were decreased. Measures of health promotion and self-efficacy were positively associated with perceived mental health status, life satisfaction and participation. Barriers to healthy activities were negatively associated with health promotion, self-efficacy and perceived mental health status. Health and wellness status was below desired levels for the study cohort, and comparable to other disability populations. Better understanding of associations among health-related constructs is needed. Continued research on conceptually-based health and wellness interventions for persons with TBI is recommended.

Enhancing ecosystem restoration efficiency through spatial and temporal coordination

PubMed Central

Neeson, Thomas M.; Ferris, Michael C.; Diebel, Matthew W.; Doran, Patrick J.; O’Hanley, Jesse R.; McIntyre, Peter B.

2015-01-01

In many large ecosystems, conservation projects are selected by a diverse set of actors operating independently at spatial scales ranging from local to international. Although small-scale decision making can leverage local expert knowledge, it also may be an inefficient means of achieving large-scale objectives if piecemeal efforts are poorly coordinated. Here, we assess the value of coordinating efforts in both space and time to maximize the restoration of aquatic ecosystem connectivity. Habitat fragmentation is a leading driver of declining biodiversity and ecosystem services in rivers worldwide, and we simultaneously evaluate optimal barrier removal strategies for 661 tributary rivers of the Laurentian Great Lakes, which are fragmented by at least 6,692 dams and 232,068 road crossings. We find that coordinating barrier removals across the entire basin is nine times more efficient at reconnecting fish to headwater breeding grounds than optimizing independently for each watershed. Similarly, a one-time pulse of restoration investment is up to 10 times more efficient than annual allocations totaling the same amount. Despite widespread emphasis on dams as key barriers in river networks, improving road culvert passability is also essential for efficiently restoring connectivity to the Great Lakes. Our results highlight the dramatic economic and ecological advantages of coordinating efforts in both space and time during restoration of large ecosystems. PMID:25918378

Comparison of the effects of artificial and natural barriers on large African carnivores: implications for interspecific relationships and connectivity.

PubMed

Cozzi, Gabriele; Broekhuis, Femke; McNutt, J Weldon; Schmid, Bernhard

2013-05-01

1. Physical barriers contribute to habitat fragmentation, influence species distribution and ranging behaviour, and impact long-term population viability. Barrier permeability varies among species and can potentially impact the competitive balance within animal communities by differentially affecting co-occurring species. The influence of barriers on the spatial distribution of species within whole communities has nonetheless received little attention. 2. During a 4-year period, we studied the influence of a fence and rivers, two landscape features that potentially act as barriers on space use and ranging behaviour of lions Panthera leo, spotted hyenas Crocuta crocuta, African wild dogs Lycaon pictus and cheetahs Acinonyx jubatus in Northern Botswana. We compared the tendencies of these species to cross the barriers using data generated from GPS-radio collars fitted to a total of 35 individuals. Barrier permeability was inferred by calculating the number of times animals crossed a barrier vs. the number of times they did not cross. Finally, based on our results, we produced a map of connectivity for the broader landscape system. 3. Permeability varied significantly between fence and rivers and among species. The fence represented an obstacle for lions (permeability = 7.2%), while it was considerably more permeable for hyenas (35.6%) and wild dogs and cheetahs (≥ 50%). In contrast, the rivers and associated floodplains were relatively permeable to lions (14.4%) while they represented a nearly impassable obstacle for the other species (<2%). 4. The aversion of lions to cross the fence resulted in a relatively lion-free habitat patch on one side of the fence, which might provide a potential refuge for other species. For instance, the competitively inferior wild dogs used this refuge significantly more intensively than the side of the fence with a high presence of lions. 5. We showed that the influence of a barrier on the distribution of animals could potentially result in a broad-scale modification of community structure and ecology within a guild of co-occurring species. As habitat fragmentation increases, understanding the impact of barriers on species distributions is thus essential for the implementation of landscape-scale management strategies, the development and maintenance of corridors and the enhancement of connectivity. © 2013 The Authors. Journal of Animal Ecology © 2013 British Ecological Society.

Nested modeling approach to quantify sediment transport pathways and temporal variability of barrier island evolution

NASA Astrophysics Data System (ADS)

Long, J. W.; Dalyander, S.; Sherwood, C. R.; Thompson, D. M.; Plant, N. G.

2012-12-01

The Chandeleur Islands, situated off the coast of Louisiana in the Gulf of Mexico, comprise a sand-starved barrier island system that has been disintegrating over the last decade. The persistent sediment transport in this area is predominantly directed alongshore but overwash and inundation during storm conditions has fragmented the island and reduced the subaerial extent by almost 75% since 2001. From 2010-2011 a sand berm was constructed along the Gulf side of the island adding 20 million cubic yards of sediment to this barrier island system. The redistribution of this sediment, particularly whether it remains in the active system and progrades the barrier island, has been evaluated using a series of numerical models and an extensive set of in situ and remote sensing observations. We have developed a coupled numerical modeling system capable of simulating morphologic evolution of the sand berm and barrier island using observations and predictions of regional and nearshore oceanographic processes. A nested approach provides large scale oceanographic information to force island evolution in a series of smaller grids, including two nearshore domains that are designed to simulate (1) the persistent alongshore sediment transport O(months-years) and (2) the overwash and breaching of the island/berm due to cross-shore forcing driven by winter cold fronts and tropical storms (O(hours-days)). The coupled model is evaluated using the observations of waves, water levels, currents, and topographic/morphologic change. Modeled processes are then used to identify the dominant sediment transport pathways and quantify the role of alongshore and cross-shore sediment transport in evolving the barrier island over a range of temporal scales.

Healthcare-seeking behaviour, barriers and mental health of non-domestic migrant workers in Singapore

PubMed Central

Ang, Jia Wei; Chia, Colin; Koh, Calvin J; Chua, Brandon W B; Narayanaswamy, Shyamala; Wijaya, Limin; Chan, Lai Gwen; Goh, Wei Leong

2017-01-01

Background Low-wage migrant workers are vulnerable to healthcare inequities. We sought to identify potential barriers to healthcare and risk factors for mental health issues in non-domestic migrant workers in Singapore, and identify high-risk subgroups. Methods A cross-sectional, interviewer-administered survey of 433 non-domestic migrant workers was conducted at subsidised clinics and a foreign worker dormitory from July to August 2016. Questions assessed healthcare usage patterns, affordability issues, barriers to care and psychological distress using a validated screening scale (Kessler-6). Findings Bangladeshi workers surveyed were more likely to be single, have more financial dependents, a lower level of education and salary and pay higher agent fees (p<0.01). 61.4% of workers reported that they had insurance, but had poor understanding of whether it covered inpatient/outpatient expenses. The majority of workers had not, or were not sure if they had, received information about company-bought insurance (72.4%). Among those who had, most reported that information was not in their native language (67.7%). Non-specific psychological distress was found in 21.9%, as estimated by the Kessler-6 scale. Multivariate analysis found that psychological distress was independently associated with Bangladeshi nationals (OR 2.98, 95% CI 1.58 to 5.62; p=0.001) and previous experience of financial barriers to healthcare (OR 3.86, 95% CI 2.25 to 6.62; p<0.0001). Interpretation We identified gaps in non-domestic migrant workers' knowledge of healthcare coverage, and substantial financial barriers to healthcare. The Bangladeshi population in our study was at higher risk of such barriers and psychological distress. These represent areas for further research and intervention. PMID:28589024

Measurements and Simulations of Surface Dielectric Barrier Discharges Used as Plasma Actuators

NASA Technical Reports Server (NTRS)

Hoskinson, Alan R.

2012-01-01

This report is a Ph.D. dissertation performed under NRA cooperative agreement and submitted as part of the final report. Asymmetric surface dielectric barrier discharges (DBDs) have shown promise for use as aerodynamic actuators for active flow control. In this project we studied DBD actuators experimentally and numerically. Our DBDs used a symmetric triangular high voltage waveform to generate plasma in atmospheric pressure air. Time-averaged measurements indicated that the induced force of a single barrier actuator design (one electrode insulated from the plasma) can be increased exponentially above the results of previous studies by decreasing both the length and thickness of the electrode exposed to the plasma. This increased force may allow these devices to control flow separation in a wider range of flow environments. Experiments using an intensified digital camera to examine the plasma on time scales of a few nanoseconds showed that, in addition to the previously-observed filamentary and jet-like plasma structures, discharges with very thin exposed electrodes exhibited a weak but constant plasma immediately adjacent to those electrodes. In double-barrier actuators (both electrodes insulated), decreasing the diameter of the narrower electrode lead to increasing forces, and recorded images showed the simultaneous existence of both filamentary and jet-like plasma structures. The development and application of a time-dependent, two-dimensional computational fluid plasma model has aided in understanding the detailed physics of surface DBDs at all-time scales. For simulated single-barrier discharges, the model qualitatively reproduced the filamentary and jet-like micro-discharge structures. The model was somewhat successful in reproducing the observed characteristics of double-barrier actuators. For both actuator geometries, the model indicated that the majority of the forces induced on the neutral gas occur in between micro-discharges as the plasmas decay.

Analytical modeling of trilayer graphene nanoribbon Schottky-barrier FET for high-speed switching applications.

PubMed

Rahmani, Meisam; Ahmadi, Mohammad Taghi; Abadi, Hediyeh Karimi Feiz; Saeidmanesh, Mehdi; Akbari, Elnaz; Ismail, Razali

2013-01-30

Recent development of trilayer graphene nanoribbon Schottky-barrier field-effect transistors (FETs) will be governed by transistor electrostatics and quantum effects that impose scaling limits like those of Si metal-oxide-semiconductor field-effect transistors. The current-voltage characteristic of a Schottky-barrier FET has been studied as a function of physical parameters such as effective mass, graphene nanoribbon length, gate insulator thickness, and electrical parameters such as Schottky barrier height and applied bias voltage. In this paper, the scaling behaviors of a Schottky-barrier FET using trilayer graphene nanoribbon are studied and analytically modeled. A novel analytical method is also presented for describing a switch in a Schottky-contact double-gate trilayer graphene nanoribbon FET. In the proposed model, different stacking arrangements of trilayer graphene nanoribbon are assumed as metal and semiconductor contacts to form a Schottky transistor. Based on this assumption, an analytical model and numerical solution of the junction current-voltage are presented in which the applied bias voltage and channel length dependence characteristics are highlighted. The model is then compared with other types of transistors. The developed model can assist in comprehending experiments involving graphene nanoribbon Schottky-barrier FETs. It is demonstrated that the proposed structure exhibits negligible short-channel effects, an improved on-current, realistic threshold voltage, and opposite subthreshold slope and meets the International Technology Roadmap for Semiconductors near-term guidelines. Finally, the results showed that there is a fast transient between on-off states. In other words, the suggested model can be used as a high-speed switch where the value of subthreshold slope is small and thus leads to less power consumption.

Identifying Impacts of Hydropower Regulation on Salmonid Habitats to Guide River Restoration for Existing Schemes and Mitigate Adverse Effects of Future Developments

NASA Astrophysics Data System (ADS)

Buddendorf, B.; Geris, J.; Malcolm, I.; Wilkinson, M.; Soulsby, C.

2015-12-01

A decrease in longitudinal connectivity in riverine ecosystems resulting from the construction of transverse barriers has been identified as a major threat to biodiversity. For example, Atlantic Salmon (Salmo salar) have a seasonal variety of hydraulic habitat requirements for their different life stages. However, hydropower impoundments impact the spatial and temporal connectivity of natural habitat along many salmon rivers in ways that are not fully understood. Yet, these changes may affect the sustainability of habitat at local and regional scales and so ultimately the conservation of the species. Research is therefore needed both to aid the restoration and management of rivers impacted by previous hydropower development and guide new schemes to mitigate potentially adverse effects. To this end we assessed the effects of hydropower development on the flow related habitat conditions for different salmon life stages in Scottish rivers at different spatial scales. We used GIS techniques to map the changes in structural connectivity at regional scales, applying a weighting for habitat quality. Next, we used hydrological models to simulate past and present hydrologic conditions that in turn drive reach-scale hydraulic models to assess the impacts of regulation on habitat suitability in both space and time. Preliminary results indicate that: 1) impacts on connectivity depend on the location of the barrier within the river network; 2) multiple smaller barriers may have a potentially lower impact than a single larger barrier; 3) there is a relationship between habitat and connectivity where losing less but more suitable habitat potentially has a disproportionally large impact; 4) the impact of flow regulation can lead to a deterioration of habitat quality, though the effects are spatially variable and the extent of the impact depends on salmon life stage. This work can form a basis for using natural processes to perform targeted and cost-effective restoration of rivers.

Electrical degradation of double-Schottky barrier in ZnO varistors

NASA Astrophysics Data System (ADS)

He, Jinliang; Cheng, Chenlu; Hu, Jun

2016-03-01

Researches on electrical degradation of double-Schottky barrier in ZnO varistors are reviewed, aimed at the constitution of a full picture of universal degradation mechanism within the perspective of defect. Recent advances in study of ZnO materials by atomic-scale first-principles calculations are partly included and discussed, which brings to our attention distinct cognition on the native point defects and their profound impact on degradation.

Coastal Inlets Research Program. Barrier Island Migration Over a Consolidating Substrate

DTIC Science & Technology

2009-09-01

the toe of the dune to the high water line) for full development of eolian transport. However, the original Shore Protection Manual (1984...tested. Barrier islands overlying a compressible substrate are more likely to have reduced dune elevations due to consolidation, incur overall...migra- tion when the dune reaches a critical elevation with respect to the prev- alent storm conditions. Initial large-scale infusion of sand from an

Electrical degradation of double-Schottky barrier in ZnO varistors

DOE Office of Scientific and Technical Information (OSTI.GOV)

He, Jinliang, E-mail: hejl@tsinghua.edu.cn; Cheng, Chenlu; Hu, Jun

2016-03-15

Researches on electrical degradation of double-Schottky barrier in ZnO varistors are reviewed, aimed at the constitution of a full picture of universal degradation mechanism within the perspective of defect. Recent advances in study of ZnO materials by atomic-scale first-principles calculations are partly included and discussed, which brings to our attention distinct cognition on the native point defects and their profound impact on degradation.

Stigma and barriers to accessing mental health services perceived by Air Force nursing personnel.

PubMed

Hernandez, Stephen H A; Bedrick, Edward J; Parshall, Mark B

2014-11-01

We investigated perceptions of stigma and barriers associated with accessing mental health services among active component U.S. Air Force officer and enlisted nursing personnel (N = 211). The Britt and Hoge et al Stigma scale and Hoge et al Barriers to Care scale were administered via an anonymous, online survey. Stigma items pertained to concerns that might affect decisions to seek mental health treatment. Most of the sample agreed with the items "Members of my unit might have less confidence in me" and "My unit leadership might treat me differently." Approximately 20% to 46% agreed with the other four stigma items. Officer nursing personnel were significantly more likely than enlisted to agree that accessing mental health services would be embarrassing, harm their career, or cause leaders to blame them for the problem (p ≤ 0.03 for each comparison). Getting time off from work for treatment and scheduling appointments were perceived as barriers by 41% and 21% of respondents, respectively. We conclude that proportions of Air Force nursing personnel reporting concerns about potential stigmatizing consequences of seeking mental health care are substantial and similar to ranges previously reported by military service members screening positive for mental health problems after deployment. Reprint & Copyright © 2014 Association of Military Surgeons of the U.S.

A Systematic Review of Barriers and Facilitators to Minority Research Participation Among African Americans, Latinos, Asian Americans, and Pacific Islanders

PubMed Central

Duran, Nelida; Norris, Keith

2014-01-01

To assess the experienced or perceived barriers and facilitators to health research participation for major US racial/ethnic minority populations, we conducted a systematic review of qualitative and quantitative studies from a search on PubMed and Web of Science from January 2000 to December 2011. With 44 articles included in the review, we found distinct and shared barriers and facilitators. Despite different expressions of mistrust, all groups represented in these studies were willing to participate for altruistic reasons embedded in cultural and community priorities. Greater comparative understanding of barriers and facilitators to racial/ethnic minorities’ research participation can improve population-specific recruitment and retention strategies and could better inform future large-scale prospective quantitative and in-depth ethnographic studies. PMID:24328648

Expectations of barriers to psychosocial care: views of parents and adolescents in the community.

PubMed

Nanninga, Marieke; Reijneveld, Sijmen A; Knorth, Erik J; Jansen, Danielle E M C

2016-01-01

Parents with a child suffering from psychosocial problems frequently experience barriers to psychosocial care, which may hinder access. Expectations of barriers may have the same effect, but evidence is lacking. The aim of this study is to examine parents' and adolescents' expectations of barriers regarding psychosocial care for the child, along with associated child and family characteristics. We obtained data on an age-stratified random sample of school children/pupils aged 4-18 via questionnaires (N = 666; response rate 70.3 %). Expectations of barriers to psychosocial care were measured with the "Barriers to Treatment Participation Scale-Expectancies" questionnaire (BTPS-exp). Results showed that 64 % of the parents of children below age 12, 59 % of the parents of adolescents (age 12-18), and 84 % of the adolescents expected one or more barriers. Parents and adolescents expected barriers most frequently with respect to irrelevance of treatment. Mainly parents with low educational level and their adolescents expected barriers regarding treatment, and quite a few characteristics of parents of adolescents were associated with expecting multiple barriers regarding treatment demands and issues, for example, single parents, parents of lower educational level and of adolescent boys, and parents of adolescents with psychosocial problems. We conclude that adolescents especially, but also their parents and parents of younger children, expect major barriers to psychosocial care, which may greatly hinder appropriate care seeking. This evidence may support professionals and policymakers in their attempts to improve access to psychosocial care.

Electronic health records: what are the most important barriers?

PubMed

Ayatollahi, Haleh; Mirani, Nader; Haghani, Hamid

2014-01-01

The process of design and adoption of electronic health records may face a number of barriers. This study aimed to compare the importance of the main barriers from the experts' point of views in Iran. This survey study was completed in 2011. The potential participants (62 experts) included faculty members who worked in departments of health information technology and individuals who worked in the Ministry of Health in Iran and were in charge of the development and adoption of electronic health records. No sampling method was used in this study. Data were collected using a Likert-scale questionnaire ranging from 1 to 5. The validity of the questionnaire was established using content and face validity methods, and the reliability was calculated using Cronbach's alpha coefficient. The response rate was 51.6 percent. The participants' perspectives showed that the most important barriers in the process of design and adoption of electronic health records were technical barriers (mean = 3.84). Financial and ethical-legal barriers, with the mean value of 3.80 were other important barriers, and individual and organizational barriers, with the mean values of 3.59 and 3.50 were found to be less important than other barriers from the experts' perspectives. Strategic planning for the creation and adoption of electronic health records in the country, creating a team of experts to assess the potential barriers and develop strategies to eliminate them, and allocating financial resources can help to overcome most important barriers to the adoption of electronic health records.

Assessing the validity and reliability of family factors on physical activity: A case study in Turkey.

PubMed

Steenson, Sharalyn; Özcebe, Hilal; Arslan, Umut; Konşuk Ünlü, Hande; Araz, Özgür M; Yardim, Mahmut; Üner, Sarp; Bilir, Nazmi; Huang, Terry T-K

2018-01-01

Childhood obesity rates have been rising rapidly in developing countries. A better understanding of the risk factors and social context is necessary to inform public health interventions and policies. This paper describes the validation of several measurement scales for use in Turkey, which relate to child and parent perceptions of physical activity (PA) and enablers and barriers of physical activity in the home environment. The aim of this study was to assess the validity and reliability of several measurement scales in Turkey using a population sample across three socio-economic strata in the Turkish capital, Ankara. Surveys were conducted in Grade 4 children (mean age = 9.7 years for boys; 9.9 years for girls), and their parents, across 6 randomly selected schools, stratified by SES (n = 641 students, 483 parents). Construct validity of the scales was evaluated through exploratory and confirmatory factor analysis. Internal consistency of scales and test-retest reliability were assessed by Cronbach's alpha and intra-class correlation. The scales as a whole were found to have acceptable-to-good model fit statistics (PA Barriers: RMSEA = 0.076, SRMR = 0.0577, AGFI = 0.901; PA Outcome Expectancies: RMSEA = 0.054, SRMR = 0.0545, AGFI = 0.916, and PA Home Environment: RMSEA = 0.038, SRMR = 0.0233, AGFI = 0.976). The PA Barriers subscales showed good internal consistency and poor to fair test-retest reliability (personal α = 0.79, ICC = 0.29, environmental α = 0.73, ICC = 0.59). The PA Outcome Expectancies subscales showed good internal consistency and test-retest reliability (negative α = 0.77, ICC = 0.56; positive α = 0.74, ICC = 0.49). Only the PA Home Environment subscale on support for PA was validated in the final confirmatory model; it showed moderate internal consistency and test-retest reliability (α = 0.61, ICC = 0.48). This study is the first to validate measures of perceptions of physical activity and the physical activity home environment in Turkey. Our results support the originally hypothesized two-factor structures for Physical Activity Barriers and Physical Activity Outcome Expectancies. However, we found the one-factor rather than two-factor structure for Physical Activity Home Environment had the best model fit. This study provides general support for the use of these scales in Turkey in terms of validity, but test-retest reliability warrants further research.

Barriers to using eHealth data for clinical performance feedback in Malawi: A case study.

PubMed

Landis-Lewis, Zach; Manjomo, Ronald; Gadabu, Oliver J; Kam, Matthew; Simwaka, Bertha N; Zickmund, Susan L; Chimbwandira, Frank; Douglas, Gerald P; Jacobson, Rebecca S

2015-10-01

Sub-optimal performance of healthcare providers in low-income countries is a critical and persistent global problem. The use of electronic health information technology (eHealth) in these settings is creating large-scale opportunities to automate performance measurement and provision of feedback to individual healthcare providers, to support clinical learning and behavior change. An electronic medical record system (EMR) deployed in 66 antiretroviral therapy clinics in Malawi collects data that supervisors use to provide quarterly, clinic-level performance feedback. Understanding barriers to provision of eHealth-based performance feedback for individual healthcare providers in this setting could present a relatively low-cost opportunity to significantly improve the quality of care. The aims of this study were to identify and describe barriers to using EMR data for individualized audit and feedback for healthcare providers in Malawi and to consider how to design technology to overcome these barriers. We conducted a qualitative study using interviews, observations, and informant feedback in eight public hospitals in Malawi where an EMR system is used. We interviewed 32 healthcare providers and conducted seven hours of observation of system use. We identified four key barriers to the use of EMR data for clinical performance feedback: provider rotations, disruptions to care processes, user acceptance of eHealth, and performance indicator lifespan. Each of these factors varied across sites and affected the quality of EMR data that could be used for the purpose of generating performance feedback for individual healthcare providers. Using routinely collected eHealth data to generate individualized performance feedback shows potential at large-scale for improving clinical performance in low-resource settings. However, technology used for this purpose must accommodate ongoing changes in barriers to eHealth data use. Understanding the clinical setting as a complex adaptive system (CAS) may enable designers of technology to effectively model change processes to mitigate these barriers. Copyright © 2015. Published by Elsevier Ireland Ltd.

Barriers to using eHealth data for clinical performance feedback in Malawi: A case study

PubMed Central

Landis-Lewis, Zach; Manjomo, Ronald; Gadabu, Oliver J; Kam, Matthew; Simwaka, Bertha N; Zickmund, Susan L; Chimbwandira, Frank; Douglas, Gerald P; Jacobson, Rebecca S

2016-01-01

Introduction Sub-optimal performance of healthcare providers in low-income countries is a critical and persistent global problem. The use of electronic health information technology (eHealth) in these settings is creating large-scale opportunities to automate performance measurement and provision of feedback to individual healthcare providers, to support clinical learning and behavior change. An electronic medical record system (EMR) deployed in 66 antiretroviral therapy clinics in Malawi collects data that supervisors use to provide quarterly, clinic-level performance feedback. Understanding barriers to provision of eHealth-based performance feedback for individual healthcare providers in this setting could present a relatively low-cost opportunity to significantly improve the quality of care. Objective The aims of this study were to identify and describe barriers to using EMR data for individualized audit and feedback for healthcare providers in Malawi and to consider how to design technology to overcome these barriers. Methods We conducted a qualitative study using interviews, observations, and informant feedback in eight public hospitals in Malawi where an EMR is used. We interviewed 32 healthcare providers and conducted seven hours of observation of system use. Results We identified four key barriers to the use of EMR data for clinical performance feedback: provider rotations, disruptions to care processes, user acceptance of eHealth, and performance indicator lifespan. Each of these factors varied across sites and affected the quality of EMR data that could be used for the purpose of generating performance feedback for individual healthcare providers. Conclusion Using routinely collected eHealth data to generate individualized performance feedback shows potential at large-scale for improving clinical performance in low-resource settings. However, technology used for this purpose must accommodate ongoing changes in barriers to eHealth data use. Understanding the clinical setting as a complex adaptive system (CAS) may enable designers of technology to effectively model change processes to mitigate these barriers. PMID:26238704

The relative importance of patient-reported barriers to colorectal cancer screening.

PubMed

Jones, Resa M; Woolf, Steven H; Cunningham, Tina D; Johnson, Robert E; Krist, Alex H; Rothemich, Stephen F; Vernon, Sally W

2010-05-01

Colorectal cancer (CRC) screening rates are suboptimal. The most important barriers identified by patients are poorly understood. A comprehensive assessment of barriers to all recommended modalities is needed. In 2007, a questionnaire was mailed to 6100 patients, aged 50-75 years, from 12 family medicine practices in the Virginia Ambulatory Care Outcomes Research Network. People aged 65-75 years and African Americans were oversampled. Patients were asked to rate 19-21 barriers to each of four recommended tests. In 2008, responses were coded on a 5-point scale; higher scores reflected stronger barrier endorsement. The response rate was 55% (n=3357). Approximately 40% of respondents were aged >/=65 years, 30% were African-American, and 73% were adherent to screening. A clinician's failure to suggest screening and not knowing testing was necessary received the highest mean scores as barriers. Financial concerns and misconceptions were also cited. Barrier scores differed depending on whether respondents were never screened, overdue for screening, or adherent to guidelines. The top five barriers for each modality included test-specific barriers (e.g., handling stool, bowel preparation), which often outranked generic barriers to screening. Not knowing testing was necessary was a top barrier for all tests but colonoscopy. Although physician advice and awareness of the need for screening are important, barriers to screening are not homogenous across tests, and test-specific barriers warrant consideration in designing strategies to improve screening rates. Barrier scores differ by screening status, highlighting the need to address prior screening experience. Evidence that patients are more familiar with colonoscopy than with other modalities suggests an opportunity to improve screening rates by educating patients about alternative tests. 2010 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

Localization and elasticity in entangled polymer liquids as a mesoscopic glass transition

NASA Astrophysics Data System (ADS)

Schweizer, Kenneth

2010-03-01

The reptation-tube model is widely viewed as the correct zeroth order model for entangled linear polymer dynamics under quiescent conditions. Its key ansatz is the existence of a mesoscopic dynamical length scale that prohibits transverse chain motion beyond a tube diameter of order 3-10 nm. However, the theory is phenomenological and lacks a microscopic foundation, and many fundamental questions remain unanswered. These include: (i) where does the confining tube field come from and can it be derived from statistical mechanics? (ii) what is the microscopic origin of the magnitude, and power law scaling with concentration and packing length, of the plateau shear modulus? (iii) is the tube diameter time-dependent? (iv) does the confinement field contribute to elasticity ? (v) do entanglement constraints have a finite strength? Building on our new force-level theories for the dynamical crossover and activated barrier hopping in glassy colloidal suspensions and polymer melts, a first principles self-consistent theory has been developed for entangled polymers. Its basic physical elements, and initial results that address the questions posed above, will be presented. The key idea is that beyond a critical degree of polymerization, the chain connectivity and excluded volume induced intermolecular correlation hole drives temporary localization on an intermediate length scale resulting in a mesoscopic ``ideal kinetic glass transition.'' Large scale isotropic motion is effectively quenched due to the emergence of chain length dependent entropic barriers. However, the barrier height is not infinite, resulting in softening of harmonic localization at large displacements, temporal increase of the confining length scale, and a finite strength of entanglement constraints which can be destroyed by applied stress.

New tuberculosis technologies: challenges for retooling and scale-up.

PubMed

Pai, M; Palamountain, K M

2012-10-01

The availability of new tools does not mean that they will be adopted, used correctly, scaled up or have public health impact. Experience to date with new diagnostics suggests that many national tuberculosis programmes (NTPs) in high-burden countries are reluctant to adopt and scale up new tools, even when these are backed by evidence and global policy recommendations. We suggest that there are several common barriers to effective national adoption and scale-up of new technologies: global policy recommendations that do not provide sufficient information for scale-up, complex decision-making processes and weak political commitment at the country level, limited engagement of and support to NTP managers, high cost of tools and poor fit with user needs, unregulated markets and inadequate business models, limited capacity for laboratory strengthening and implementation research, and insufficient advocacy and donor support. Overcoming these barriers will require enhanced country-level advocacy, resources, technical assistance and political commitment. Some of the BRICS (Brazil, Russia, India, China, South Africa) countries are emerging as early adopters of policies and technologies, and are increasing their investments in TB control. They may provide the first opportunities to fully assess the public health impact of new tools.

Effect of the δ-potential on spin-dependent electron tunneling in double barrier semiconductor heterostructure

NASA Astrophysics Data System (ADS)

Chandrasekar, L. Bruno; Gnanasekar, K.; Karunakaran, M.

2018-06-01

The effect of δ-potential was studied in GaAs/Ga0.6Al0·4As double barrier heterostructure with Dresselhaus spin-orbit interaction. The role of barrier height and position of the δ- potential in the well region was analysed on spin-dependent electron tunneling using transfer matrix method. The spin-separation between spin-resonances on energy scale depends on both height and position of the δ- potential, whereas the tunneling life time of electrons highly influenced by the position of the δ- potential and not on the height. These results might be helpful for the fabrication of spin-filters.

Advances in the Dynallax solid-state dynamic parallax barrier autostereoscopic visualization display system.

PubMed

Peterka, Tom; Kooima, Robert L; Sandin, Daniel J; Johnson, Andrew; Leigh, Jason; DeFanti, Thomas A

2008-01-01

A solid-state dynamic parallax barrier autostereoscopic display mitigates some of the restrictions present in static barrier systems, such as fixed view-distance range, slow response to head movements, and fixed stereo operating mode. By dynamically varying barrier parameters in real time, viewers may move closer to the display and move faster laterally than with a static barrier system, and the display can switch between 3D and 2D modes by disabling the barrier on a per-pixel basis. Moreover, Dynallax can output four independent eye channels when two viewers are present, and both head-tracked viewers receive an independent pair of left-eye and right-eye perspective views based on their position in 3D space. The display device is constructed by using a dual-stacked LCD monitor where a dynamic barrier is rendered on the front display and a modulated virtual environment composed of two or four channels is rendered on the rear display. Dynallax was recently demonstrated in a small-scale head-tracked prototype system. This paper summarizes the concepts presented earlier, extends the discussion of various topics, and presents recent improvements to the system.

Barriers to return to work after burn injuries.

PubMed

Esselman, Peter C; Askay, Shelley Wiechman; Carrougher, Gretchen J; Lezotte, Dennis C; Holavanahalli, Radha K; Magyar-Russell, Gina; Fauerbach, James A; Engrav, Loren H

2007-12-01

To identify barriers to return to work after burn injury as identified by the patient. A cohort study with telephone interview up to 1 year. Hospital-based burn centers at 3 national sites. Hospitalized patients (N=154) meeting the American Burn Association criteria for major burn injury, employed at least 20 hours a week at the time of injury, and with access to a telephone after discharge. Patients were contacted via telephone every 2 weeks up to 4 months, then monthly up to 1 year after discharge. A return to work survey was used to identify barriers that prevented patients from returning to work. A graphic rating scale determined the impact of each barrier. By 1 year, 79.7% of patients returned to work. Physical and wound issues were barriers early after discharge. Although physical abilities continued to be a significant barrier up to 1 year, working conditions (temperature, humidity, safety) and psychosocial factors (nightmares, flashbacks, appearance concerns) became important issues in those with long-term disability. The majority of patients return to work after a burn injury. Although physical and work conditions are important barriers, psychosocial issues need to be evaluated and treated to optimize return to work.

Economically Sustainable Scaling of Photovoltaics to Meet Climate Targets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Needleman, David Berney; Poindexter, Jeremy R.; Kurchin, Rachel C.

To meet climate goals, photovoltaics (PV) deployment will have to grow rapidly over the next fifteen years. We identify two barriers to this growth: scale-up of manufacturing capacity and the cost of PV module production. We explore several technoeconomic approaches to overcoming these barriers and identify deep reductions in the capital intensity (capex) of PV module manufacturing and large increases in module efficiency as the most promising routes to rapid deployment. Given the lag inherent in rolling out new technology, we explore an approach where growth is fueled by debt or subsidies in the short-term and technological advances in themore » medium term. Finally, we analyze the current capex structure of crystalline silicon PV module manufacturing to identify potential savings.« less

Barriers to the implementation of research perceived by nurses from Osakidetza.

PubMed

Cidoncha-Moreno, M Ángeles; Ruíz de Alegría-Fernandez de Retana, Begoña

To understand the barriers to implementing nursing research findings into practice, as perceived by the nurses working in Osakidetza and to analyze if the workplace factor and time worked affect the perception of these barriers. Cross-sectional study. BARRIERS Scale questionnaire was given to a representative sample of 1,572 Basque Health Service nurses, stratified and randomized, according to scope of work and job responsibility (response rate: 43.76%). According to the research results, the first important barrier was "insufficient time on the job to implement new ideas". Nurses have perceived the organizational factor as the most important barrier in their practice. Nurses in "Special hospital departments" perceived more barriers in the "quality of research" factor than those working in "Primary Care". Years of service showed a slight influence. The nurses stated that external factors related to the organization principally interfered in implementing results into clinical practice. They placed lack of critical reading training second. Working environment and seniority mark differences in the perception of barriers. This study may help to develop strategies for planning training programs to facilitate the use of research in clinical practice, in order to provide quality care. Copyright © 2017 Elsevier España, S.L.U. All rights reserved.

Physical activity levels and perceived benefits and barriers to physical activity in HIV-infected women living in the deep south of the United States.

PubMed

Rehm, Kristina E; Konkle-Parker, Deborah

2016-09-01

Engaging in regular physical activity (PA) is important in maintaining health and increasing the overall quality of life of people living with HIV (PLWH). The deep south of the USA is known for its high rate of sedentary behavior although data on the activity levels and perceptions of the benefits and barriers to exercise in women living with HIV in the deep south are lacking. Understanding the perceived benefits and barriers to exercise can guide the development of PA interventions. We conducted a cross-sectional study to determine the PA levels and perceived benefits and barriers to exercise associated with both age and depression level in a group of HIV+ women living in the deep south. We recruited a total of 50 participants from a cohort site for the Women's Interagency HIV Study. Depression was assessed using the Center for Epidemiological Studies Depression Scale (CES-D) and benefits/barriers to exercise were measured using the Exercise Benefits and Barriers Scale (EBBS). We measured PA both subjectively and objectively using the International Physical Activity Questionnaire (IPAQ) and a Fitbit PA monitor, respectively. Our sample was predominantly African-American (96%) and the mean ±SD age, body mass index, and CES-D score were 42 ± 8.8 years, 36.6 ± 11.5 kg/m(2), and 15.6 ± 11.4, respectively. Both subjective and objective measures of PA indicated that our participants were sedentary. The greatest perceived benefit to exercise was physical performance and the greatest barrier to exercise was physical exertion. Higher overall perceived benefits were reported by women ≥43 years and women reporting higher levels of depression. There was no difference in overall barriers associated with age and depression level, but women with depression felt more fatigued by exercise. The results of this study can be helpful when designing and implementing PA interventions in women living with HIV in the deep south.

Charter Operators Spell Out Barriers to "Scaling Up"

ERIC Educational Resources Information Center

Zehr, Mary Ann

2011-01-01

The pace at which the highest-performing charter-management organizations (CMOs) are "scaling up" is being determined largely by how rapidly they can develop and hire strong leaders and acquire physical space, and by the level of support they receive for growth from city or state policies, say leaders from some charter organizations…

Partnership: The Missing Link in the Process of De-Institutionalization of Mental Health Care.

PubMed

Quah, Stella R

2017-07-01

This study discusses the main barriers to partnership between family and health services in the context of schizophrenia and de-institutionalization (reduction of the length of hospitalization whenever possible and returning the patient to the community) addressed to deal with the increasing costs and demand for health care services. Thus, in de-institutionalization the burden of care is not resolved but shared with the family, under the assumption that the patient has someone-a family caregiver-who can take up the responsibility of care at home. Despite the high burden of care faced by the family caregiver in mental illness, the necessary systematic partnership between the medical team and the family caregiver is missing. Subjects were 47 family caregivers of persons living with schizophrenia. Data were collected using in-depth interviews, structured questionnaires and attitudinal scales. Data analysis included factor analysis and odds ratios. Two types of barriers to partnership are identified in the literature: health services barriers and barriers attributed to the family. The findings confirm the health services barriers but reject the assumed family barriers.

Turbulent entrainment in a strongly stratified barrier layer

NASA Astrophysics Data System (ADS)

Pham, H. T.; Sarkar, S.

2017-06-01

Large-eddy simulation (LES) is used to investigate how turbulence in the wind-driven ocean mixed layer erodes the stratification of barrier layers. The model consists of a stratified Ekman layer that is driven by a surface wind. Simulations at a wide range of N0/f are performed to quantify the effect of turbulence and stratification on the entrainment rate. Here, N0 is the buoyancy frequency in the barrier layer and f is the Coriolis parameter. The evolution of the mixed layer follows two stages: a rapid initial deepening and a late-time growth at a considerably slower rate. During the first stage, the mixed layer thickens to the depth that is proportional to u∗/fN0 where u∗ is the frictional velocity. During the second stage, the turbulence in the mixed layer continues to deepen further into the barrier layer, and the turbulent length scale is shown to scale with u∗/N0, independent of f. The late-time entrainment rate E follows the law of E=0.035Ri∗-1/2 where Ri∗ is the Richardson number. The exponent of -1/2 is identical but the coefficient of 0.035 is much smaller relative to the value of 2-3/2 for the nonrotating boundary layer. Simulations using the KPP model (version applicable to this simple case without additional effects of Langmuir turbulence or surface buoyancy flux) also yield the entrainment scaling of E∝Ri∗-1/2; however, the proportionality coefficient varies with the stratification. The structure of the Ekman current is examined to illustrate the strong effect of stratification in the limit of large N0/f.

Economic Evaluation of Isolation of Hemicelluloses From Process Streams From Thermomechanical Pulping of Spruce

NASA Astrophysics Data System (ADS)

Persson, Tobias; Nordin, Anna-Karin; Zacchi, Guido; Jönsson, Ann-Sofi

Hemicelluloses, which are abundant in nature and have potential use in a wide variety of applications, may make an important contribution in helping relieve society of its dependence on petrochemicals. However, cost-efficient methods for the isolation of hemicelluloses are required. This article presents an economic evaluation of a full-scale process to isolate hemicelluloses from process water from a thermomechanical pulp mill. Experimental data obtained in laboratory scale were used for the scale up of the process by computer simulation. The isolation method consisted of two process steps. The suspended matter in the process water was removed by microfiltration and thereafter the hemicelluloses were concentrated by ultrafiltration, and at the same time, separated from smaller molecules and ions in the process water. The isolated hemicelluloses were intended for the production of oxygen barriers for food packaging, an application for which they have been shown to have suitable properties. The solution produced contained 30 g hemicelluloses/L with a purity (defined as the ratio between the hemicelluloses and the total solids) of approx 80%. The evaluation was performed for a plant with a daily production of 4 metric tonnes (t) of hemicelluloses, which is the estimated future need of barrier films at Tetra Pak (Lund, Sweden). The production cost was calculated to be € 670/t of hemiceluloses. This is approx 9 times lower than the price of ethylene vinyl alcohol, which is produced by petrochemicals and is currently used as an oxygen barrier in fiber-based packaging materials. This indicates that it is possible to produce oxygen barriers made of hemicelluloses at a prices that is competitive with the materials used today.

Nurses’ Perceived Barriers to and Facilitators of Research Utilization in Mainland China: A Cross-Sectional Survey

PubMed Central

Chien, Wai-Tong; Bai, Qin; Wong, Wai-Kit; Wang, Huizhen; Lu, Xueqin

2013-01-01

Despite the drive towards evidence-based practice, the extent to which research evidence is being implemented in nursing practice is unclear, particularly in developing countries. This study was to assess the levels of perceived barriers to and facilitators of research utilization in practice among Chinese nurses and inter-relationships between these barriers and facilitators and their socio-demographic characteristics. A cross-sectional, descriptive survey was conducted in 2011 with 743 registered nurses randomly selected from four general hospitals in China. They completed the Barriers to Research Utilization and Facilitators of Research Utilization scales. Correlation tests were used to test the relationships between the nurses’ perceived barriers and facilitators, their demographic characteristics and research training and involvement. The Chinese nurses’ level of perceived barriers was moderate on average and lower than that in previous research. Among the 10 top-ranked items, six were from the subscale ‘Organizational Characteristics’. Their perceived barriers were correlated positively with age and post-registration experience and negatively with research training undertaken. Junior diplomatic nurses reported a significantly higher degree of barriers than those senior ones with postgraduate education. Higher and more diverse barriers to research utilization in practice are perceived by Chinese nurses than those in Western countries and they are associated with a few socio-demographic factors. Future research on these barriers/facilitators and their relationships with occupational and socio-cultural factors in Chinese and other Asian nurses is recommended. PMID:23919099

Perceived barriers to physical activity among Nigerian stroke survivors.

PubMed

Idowu, Opeyemi Ayodiipo; Adeniyi, Ade Fatai; Ogwumike, Omoyemi Olubunmi; Fawole, Henrietta Oluwafunmilola; Akinrolie, Olayinka

2015-01-01

Benefits of physical activity in the prevention and management of stroke are well documented in the literature. There is increasing evidence that stroke survivors in South-West Nigeria are physically inactive. Data on barriers to the achievement of the recommended physical activity levels including its differences along socio-demographic characteristics among stroke survivors in South-West Nigeria are needed. The Exercise Benefits and Barrier Scale and the International Physical Activity Questionnaire were administered on 121 stroke survivors to determine their perceived barriers to physical activity and physical activity levels respectively. Information on socio-demographic data and clinical variables were also collected. The sample included 70.2% males, with majority of the participants reporting low physical activity levels (80.2%) and high perceived barriers (Mean = 48.13, SD = 7.88). The four most reported common barriers among stroke survivors were access to exercise facilities (95.0%), being embarrassed to exercise (94.2%), economic cost demands of exercise (94.2%) and notion that people in exercise clothes look funny (94.2%) respectively. There were no significant differences found in barriers to physical activity between gender (U = 1471.00, P = 0.74) and across each of: occupational status (H = 4.37, P = 0.22), age group (H = 0.82, P = 0.84) and educational levels (H = 4.56, P = 0.33). Significant difference however existed in perceived barriers across marital status categories (H = 12.87, P = 0.05). Stroke survivors indicated high perceived barriers to physical activity and these barriers were associated with marital status.

Scale transition using dislocation dynamics and the nudged elastic band method

DOE PAGES

Sobie, Cameron; Capolungo, Laurent; McDowell, David L.; ...

2017-08-01

Microstructural features such as precipitates or irradiation-induced defects impede dislocation motion and directly influence macroscopic mechanical properties such as yield point and ductility. In dislocation-defect interactions both atomic scale and long range elastic interactions are involved. Thermally assisted dislocation bypass of obstacles occurs when thermal fluctuations and driving stresses contribute sufficient energy to overcome the energy barrier. The Nudged Elastic Band (NEB) method is typically used in the context of atomistic simulations to quantify the activation barriers for a given reaction. In this work, the NEB method is generalized to coarse-grain continuum representations of evolving microstructure states beyond the discretemore » particle descriptions of first principles and atomistics. The method we employed enables the calculation of activation energies for a View the MathML source glide dislocation bypassing a [001] self-interstitial atom loop of size in the range of 4-10 nm with a spacing larger than 150nm in α-iron for a range of applied stresses and interaction geometries. This study is complemented by a comparison between atomistic and continuum based prediction of barriers.« less

Enabling Energy Efficiency and Polarity Control in Germanium Nanowire Transistors by Individually Gated Nanojunctions.

PubMed

Trommer, Jens; Heinzig, André; Mühle, Uwe; Löffler, Markus; Winzer, Annett; Jordan, Paul M; Beister, Jürgen; Baldauf, Tim; Geidel, Marion; Adolphi, Barbara; Zschech, Ehrenfried; Mikolajick, Thomas; Weber, Walter M

2017-02-28

Germanium is a promising material for future very large scale integration transistors, due to its superior hole mobility. However, germanium-based devices typically suffer from high reverse junction leakage due to the low band-gap energy of 0.66 eV and therefore are characterized by high static power dissipation. In this paper, we experimentally demonstrate a solution to suppress the off-state leakage in germanium nanowire Schottky barrier transistors. Thereto, a device layout with two independent gates is used to induce an additional energy barrier to the channel that blocks the undesired carrier type. In addition, the polarity of the same doping-free device can be dynamically switched between p- and n-type. The shown germanium nanowire approach is able to outperform previous polarity-controllable device concepts on other material systems in terms of threshold voltages and normalized on-currents. The dielectric and Schottky barrier interface properties of the device are analyzed in detail. Finite-element drift-diffusion simulations reveal that both leakage current suppression and polarity control can also be achieved at highly scaled geometries, providing solutions for future energy-efficient systems.

Pleistocene and ecological effects on continental-scale genetic differentiation in the bobcat (Lynx rufus).

PubMed

Reding, Dawn M; Bronikowski, Anne M; Johnson, Warren E; Clark, William R

2012-06-01

The potential for widespread, mobile species to exhibit genetic structure without clear geographic barriers is a topic of growing interest. Yet the patterns and mechanisms of structure--particularly over broad spatial scales--remain largely unexplored for these species. Bobcats occur across North America and possess many characteristics expected to promote gene flow. To test whether historical, topographic or ecological factors have influenced genetic differentiation in this species, we analysed 1 kb mtDNA sequence and 15 microsatellite loci from over 1700 samples collected across its range. The primary signature in both marker types involved a longitudinal cline with a sharp transition, or suture zone, occurring along the Great Plains. Thus, the data distinguished bobcats in the eastern USA from those in the western half, with no obvious physical barrier to gene flow. Demographic analyses supported a scenario of expansion from separate Pleistocene refugia, with the Great Plains representing a zone of secondary contact. Substructure within the two main lineages likely reflected founder effects, ecological factors, anthropogenic/topographic effects or a combination of these forces. Two prominent topographic features, the Mississippi River and Rocky Mountains, were not supported as significant genetic barriers. Ecological regions and environmental correlates explained a small but significant proportion of genetic variation. Overall, results implicate historical processes as the primary cause of broad-scale genetic differentiation, but contemporary forces seem to also play a role in promoting and maintaining structure. Despite the bobcat's mobility and broad niche, large-scale landscape changes have contributed to significant and complex patterns of genetic structure. © 2012 Blackwell Publishing Ltd.

Implementing Comprehensive Reform: Implications for Practice

ERIC Educational Resources Information Center

Stout, Karen A.

2016-01-01

This chapter describes the challenges and practical barriers community colleges face when implementing comprehensive reform, exploring how reforms are leading to some improvements but not often scaled improvements.

Performance evaluation of intermediate cover soil barrier for removal of heavy metals in landfill leachate.

PubMed

Suzuki, Kazuyuki; Anegawa, Aya; Endo, Kazuto; Yamada, Masato; Ono, Yusaku; Ono, Yoshiro

2008-11-01

This pilot-scale study evaluated the use of intermediate cover soil barriers for removing heavy metals in leachate generated from test cells for co-disposed fly ash from municipal solid waste incinerators, ash melting plants, and shredder residue. Cover soil barriers were mixtures of Andisol (volcanic ash soil), waste iron powder, (grinder dust waste from iron foundries), and slag fragments. The cover soil barriers were installed in the test cells' bottom layer. Sorption/desorption is an important process in cover soil bottom barrier for removal of heavy metals in landfill leachate. Salt concentrations such as those of Na, K, and Ca in leachate were extremely high (often greater than 30 gL(-1)) because of high salt content in fly ash from ash melting plants. Concentrations of all heavy metals (nickel, manganese, copper, zinc, lead, and cadmium) in test cell leachates with a cover soil barrier were lower than those of the test cell without a cover soil barrier and were mostly below the discharge limit, probably because of dilution caused by the amount of leachate and heavy metal removal by the cover soil barrier. The cover soil barriers' heavy metal removal efficiency was calculated. About 50% of copper, nickel, and manganese were removed. About 20% of the zinc and boron were removed, but lead and cadmium were removed only slightly. Based on results of calculation of the Langelier saturation index and analyses of core samples, the reactivity of the cover soil barrier apparently decreases because of calcium carbonate precipitation on the cover soil barriers' surfaces.

Differences between men and women in condom use, attitudes, and skills in substance abuse treatment seekers

PubMed Central

Calsyn, Donald A.; Peavy, K. Michelle; Wells, Elizabeth A.; Campbell, Aimee N. C.; Hatch-Maillette, Mary A; Greenfield, Shelly F.; Tross, Susan

2012-01-01

Examining attitudes and skills regarding condom use by men and women in substance abuse treatment who engage in high risk sexual behavior may help to explain their inconsistent condom use. Men and women enrolled in two multi-site HIV risk reduction studies were administered the Condom Barriers Scale, Condom Use Skills and an audio computer-assisted structured interview assessing sexual risk behavior. Men endorsed more barriers to condom use than women, especially in the Effects on Sexual Experience factor. For both men and women, stronger endorsement of barriers to condom use was associated with less use of condoms. However, the difference between condom users and condom non-users in endorsement of condom barriers in general is greater for men than women, especially for those who report having casual partners. Findings support the need to focus on gender-specific barriers to condom use in HIV/STI prevention interventions, especially risk behavior intervention techniques that address sexual experience with condoms. PMID:23414501

Determining Barriers to Use of Edible School Gardens in Illinois.

PubMed

Loftus, Lucy; Spaulding, Aslihan D; Steffen, Richard; Kopsell, Dave; Nnakwe, Nweze

2017-01-01

The objective of this study was to gather data regarding the awareness, perceived benefits, interest in, and barriers to establishment of edible school gardens in Illinois public schools. Setting/Design: This study used an online survey design. Participants included Illinois public elementary school principals and superintendents. Region and community population, current edible garden use, perception (Likert scale) of garden benefits, interest in establishment of a school edible garden, and barriers to establishment of a school edible garden were the variables of interest. Logit regression and Kruskal-Wallis with follow-up where p < 0.05 were performed. Elementary school principals and superintendents are aware of gardens and their potential benefits to students, but many barriers exist that make their use challenging. Funding, staff and volunteer support, and class time were identified as the major barriers. Region affected likelihood of garden use, and community population size also affected the odds of having an edible school garden. Data suggest that edible garden use would increase with provision of resources and organization of dedicated supporters.

Containment of a silicone fluid free surface in reduced gravity using barrier coatings

NASA Technical Reports Server (NTRS)

Pline, Alexander D.; Jacobson, Thomas P.

1988-01-01

In support of the Surface Tension Driven Convection Experiment planned for flight aboard the Space Shuttle, tests were conducted under reduced gravity in the 2.2-sec Drop Tower and the 5.0-sec Zero-G facility at the NASA Lewis Research Center. The dynamics of controlling the test fluid, a 10-cSt viscosity silicone fluid in a low gravity environment were investigated using different container designs and barrier coatings. Three container edge designs were tested without a barrier coating; a square edge, a sharp edge with a 45-deg slope, and a sawtooth edge. All three edge designs were successful in containing the fluid below the edge. G-jitter experiments were made in scaled down containers subjected to horizontal accelerations. The data showed that a barrier coating is effective in containing silicone fluid under g-levels up to 10 sup -1 sub g sub 0. In addition, a second barrier coating was found which has similar anti-wetting characteristics and is also more durable.

Transport barriers in bootstrap-driven tokamaks

NASA Astrophysics Data System (ADS)

Staebler, G. M.; Garofalo, A. M.; Pan, C.; McClenaghan, J.; Van Zeeland, M. A.; Lao, L. L.

2018-05-01

Experiments have demonstrated improved energy confinement due to the spontaneous formation of an internal transport barrier in high bootstrap fraction discharges. Gyrokinetic analysis, and quasilinear predictive modeling, demonstrates that the observed transport barrier is caused by the suppression of turbulence primarily from the large Shafranov shift. It is shown that the Shafranov shift can produce a bifurcation to improved confinement in regions of positive magnetic shear or a continuous reduction in transport for weak or negative magnetic shear. Operation at high safety factor lowers the pressure gradient threshold for the Shafranov shift-driven barrier formation. Two self-organized states of the internal and edge transport barrier are observed. It is shown that these two states are controlled by the interaction of the bootstrap current with magnetic shear, and the kinetic ballooning mode instability boundary. Election scale energy transport is predicted to be dominant in the inner 60% of the profile. Evidence is presented that energetic particle-driven instabilities could be playing a role in the thermal energy transport in this region.

Identification of potential barriers to nurse-sensitive outcome demonstration.

PubMed

Beckel, Jean; Wolf, Gail; Wilson, Roxanne; Hoolahan, Susan

2013-12-01

The objective of this study was to determine differences in chief nursing officer, Magnet(®) program director, nurse leader, and direct care RN perspectives of potential barriers to demonstration of nurse-sensitive outcomes. The Magnet Recognition Program(®) and other designations are focusing on patient outcomes. No evidence is available addressing barriers to demonstration of nursing outcomes at multiple levels of practice. A Likert scale tool was developed and administered to 526 attendees at the 2012 national Magnet conference. Questions related to available resources, benchmarks, outcome demonstration process understanding, perception of value, and competing priorities. Significant perception differences by role were demonstrated related to available resources, competing priorities, and process understanding supporting demonstration of nurse-sensitive outcomes. No significant differences were identified related to benchmarks or perception of process value to the organization. This study provides new information demonstrating potential barriers to demonstration of nurse-sensitive outcomes differing by role. Opportunity exists to develop systems and processes to reduce perceived barriers among the nursing workforce.

Cultural adaptation and validation of an instrument on barriers for the use of research results.

PubMed

Ferreira, Maria Beatriz Guimarães; Haas, Vanderlei José; Dantas, Rosana Aparecida Spadoti; Felix, Márcia Marques Dos Santos; Galvão, Cristina Maria

2017-03-02

to culturally adapt The Barriers to Research Utilization Scale and to analyze the metric validity and reliability properties of its Brazilian Portuguese version. methodological research conducted by means of the cultural adaptation process (translation and back-translation), face and content validity, construct validity (dimensionality and known groups) and reliability analysis (internal consistency and test-retest). The sample consisted of 335 nurses, of whom 43 participated in the retest phase. the validity of the adapted version of the instrument was confirmed. The scale investigates the barriers for the use of the research results in clinical practice. Confirmatory factorial analysis demonstrated that the Brazilian Portuguese version of the instrument is adequately adjusted to the dimensional structure the scale authors originally proposed. Statistically significant differences were observed among the nurses holding a Master's or Doctoral degree, with characteristics favorable to Evidence-Based Practice, and working at an institution with an organizational cultural that targets this approach. The reliability showed a strong correlation (r ranging between 0.77 and 0.84, p<0.001) and the internal consistency was adequate (Cronbach's alpha ranging between 0.77 and 0.82). the Brazilian Portuguese version of The Barriers Scale was valid and reliable in the group studied. efectuar la adaptación cultural del instrumento The Barriers to Research Utilization Scale, y analizar propiedades métricas de validez y confiabilidad de su versión para portugués brasileño. investigación metodológica conducida mediante el proceso de adaptación cultural (traducción y retrotraducción), validez de faz y contenido, validez de constructo (dimensionalidad y grupos conocidos) y análisis de fiabilidad (consistencia interna y test-retest). La muestra incluyó 335 enfermeros, de los cuales 43 participaron de la etapa retest. la validez de la versión adaptada del instrumento fue confirmada, la escala investiga las barreras para la utilización de resultados de investigación en la práctica clínica. El análisis factorial confirmatorio demostró que la versión del instrumento para el portugués brasileño está adecuadamente ajustado a la estructura dimensional originalmente propuesta por los autores de la escala. Fueron observadas diferencias estadísticamente significantes entre los enfermeros con título de maestría o doctorado, con características favorables a la Práctica Basada en Evidencias, y actuantes en institución con cultura organizacional dirigida hacia tal aproximación. La fiabilidad presentó correlación fuerte (r variando entre 0,77 y 0,84, p<0,001) y la consistencia interna fue adecuada (alfa de Cronbach variando entre 0,77 y 0,82). la versión para el portugués brasileño del instrumento The Barriers Scale se mostró válida y confiable en el grupo estudiado. realizar adaptação cultural do instrumento The Barriers to Research Utilization Scale, e analisar propriedades métricas de validade e confiabilidade da sua versão para o português brasileiro. pesquisa metodológica conduzida por meio do processo de adaptação cultural (tradução e retrotradução), validade de face e conteúdo, validade de construto (dimensionalidade e grupos conhecidos) e análise da confiabilidade (consistência interna e teste-reteste). A amostra foi composta de 335 enfermeiros, desses, 43 participaram da etapa reteste. a validade da versão adaptada do instrumento foi confirmada, a escala investiga as barreiras para a utilização de resultados de pesquisa na prática clínica. A análise fatorial confirmatória demonstrou que a versão do instrumento para o português brasileiro está adequadamente ajustada à estrutura dimensional originalmente proposta pelos autores da escala. Observou-se diferenças estatisticamente significantes entre os enfermeiros mestres ou doutores, com características favoráveis a Prática Baseada em Evidências, e atuantes em instituição com cultura organizacional direcionada para tal abordagem. A confiabilidade apresentou correlação forte (r variando entre 0,77e 0,84, p<0,001) e a consistência interna foi adequada (alfa de Cronbach variando entre 0,77 e 0,82) . a versão para o português brasileiro do instrumento The Barriers Scale demonstrou-se válida e confiável no grupo estudado.

"It's Really Making a Difference": How Small-Scale Research Projects Can Enhance Teaching and Learning

ERIC Educational Resources Information Center

Dexter, Barbara; Seden, Roy

2012-01-01

Following an internal evaluation exercise, using Action Research, this paper identifies the positive impact of small-scale research projects on teaching and learning at a single case study UK University. Clear evidence is given of how the projects benefited students and staff, and enhanced institutional culture. Barriers to better practice are…

Motivation, Academic Assessments and First-Semester Success at a Midwestern Technical College

ERIC Educational Resources Information Center

Dillon, Sarah A.

2017-01-01

This study examined college admission criteria and college readiness in an effort to reduce barriers in college admission. The Academic Motivation Scale (AMS) was administered to a convenience sample of 74 participants among 503 students during their first semester at a two-year college. Scale scores were compared to demographic characteristics,…

Energy Barriers and Hysteresis in Martensitic Phase Transformations

DTIC Science & Technology

2008-08-01

glacial acetic acid (CH3COOH) and 10-15% perchloric acid (HCLO4) by volume, the cathode was stainless steel , the anode was stainless steel or Ti, the...Submitted to Acta Materialia Energy barriers and hysteresis in martensitic phase transformations Zhiyong Zhang, Richard D. James and Stefan Müller...hysteresis based on the growth from a small scale of fully developed austenite martensite needles. In this theory the energy of the transition layer plays a

Barriers and facilitators experienced in collaborative prospective research in orthopaedic oncology: A qualitative study.

PubMed

Rendon, J S; Swinton, M; Bernthal, N; Boffano, M; Damron, T; Evaniew, N; Ferguson, P; Galli Serra, M; Hettwer, W; McKay, P; Miller, B; Nystrom, L; Parizzia, W; Schneider, P; Spiguel, A; Vélez, R; Weiss, K; Zumárraga, J P; Ghert, M

2017-05-01

As tumours of bone and soft tissue are rare, multicentre prospective collaboration is essential for meaningful research and evidence-based advances in patient care. The aim of this study was to identify barriers and facilitators encountered in large-scale collaborative research by orthopaedic oncological surgeons involved or interested in prospective multicentre collaboration. All surgeons who were involved, or had expressed an interest, in the ongoing Prophylactic Antibiotic Regimens in Tumour Surgery (PARITY) trial were invited to participate in a focus group to discuss their experiences with collaborative research in this area. The discussion was digitally recorded, transcribed and anonymised. The transcript was analysed qualitatively, using an analytic approach which aims to organise the data in the language of the participants with little theoretical interpretation. The 13 surgeons who participated in the discussion represented orthopaedic oncology practices from seven countries (Argentina, Brazil, Italy, Spain, Denmark, United States and Canada). Four categories and associated themes emerged from the discussion: the need for collaboration in the field of orthopaedic oncology due to the rarity of the tumours and the need for high level evidence to guide treatment; motivational factors for participating in collaborative research including establishing proof of principle, learning opportunity, answering a relevant research question and being part of a collaborative research community; barriers to participation including funding, personal barriers, institutional barriers, trial barriers, and administrative barriers and facilitators for participation including institutional facilitators, leadership, authorship, trial set-up, and the support of centralised study coordination. Orthopaedic surgeons involved in an ongoing international randomised controlled trial (RCT) were motivated by many factors to participate. There were a number of barriers to and facilitators for their participation. There was a collective sense of fatigue experienced in overcoming these barriers, which was mirrored by a strong collective sense of the importance of, and need for, collaborative research in this field. The experiences were described as essential educational first steps to advance collaborative studies in this area. Knowledge gained from this study will inform the development of future large-scale collaborative research projects in orthopaedic oncology. Cite this article: J. S. Rendon, M. Swinton, N. Bernthal, M. Boffano, T. Damron, N. Evaniew, P. Ferguson, M. Galli Serra, W. Hettwer, P. McKay, B. Miller, L. Nystrom, W. Parizzia, P. Schneider, A. Spiguel, R. Vélez, K. Weiss, J. P. Zumárraga, M. Ghert. Barriers and facilitators experienced in collaborative prospective research in orthopaedic oncology: A qualitative study. Bone Joint Res 2017;6:-314. DOI: 10.1302/2046-3758.65.BJR-2016-0192.R1. © 2017 Ghert et al.

A Temporal Assessment of Barrier Island Vulnerability to Extreme Wave Events, Virginia Coast Reserve

NASA Astrophysics Data System (ADS)

Oster, D. J.; Moore, L. J.; Doran, K. J.; Stockdon, H. F.

2010-12-01

Barrier island vulnerability to storm-generated waves is directly related to interactions between shoreface morphology and surf-zone dynamics. During storms, the seaward-most dune often limits the landward extent of wave energy; however, if maximum wave run-up exceeds the elevation of the top of the dune, overwash or inundation may occur. The ‘Storm Impact Scale’ presented by Sallenger (2000) classifies barrier beach vulnerability to individual storm events based on the elevation of the frontal dune crest and toe relative to maximum wave run-up. Changes to the dune and beachface can occur over a range of time scales, altering local vulnerability to extreme waves from storms, even as a storm is occurring. As sea level continues to rise, barrier beaches will become increasingly vulnerable to overwash and inundation from a greater number of storms. Our objective is to assess temporal trends in barrier island vulnerability while also exploring island-chain-wide response and recovery from two notably different storm events (Nor’Ida and Hurricane Bonnie) along the undeveloped barrier islands of the Virginia Coast Reserve (VCR). We compare shoreline position and elevations of the frontal dune crest (DHIGH) and dune toe (DLOW) across four lidar data sets collected between 1998-2010. Observed significant wave height and period from the National Data Buoy Center and the Duck, NC Field Research Facility for the time period between 1985 and 2009 are classified to represent one-year, five-year, and ten-year storm events that serve as the basis for comparison of island vulnerability through time to a range of storm severity. Initial results reveal significant spatial and temporal variation in barrier island vulnerability to storms throughout the VCR. Despite the range of variability, all three beach features (i.e., shoreline position, DHIGH and DLOW), have moved landward indicating large-scale, widespread migration, or narrowing, of VCR barrier island landforms over the last 10 years. Potentially evolving long-term trends in island vulnerability appear to be difficult to detect, likely due to the short time window of analysis and the preferential capture of short-term variations as two out of the four lidar data sets were collected immediately following a storm event. Further statistical analysis of changes in frontal dune height (DHIGH) and the distance between the dune toe (DLOW) and shoreline will provide insight into short-term responses to individual storms as well as the potential for future long-term changes in barrier island vulnerability, contributing to a better understanding of barrier island response to rising seas and severe storms.

ZnO Schottky barriers and Ohmic contacts

NASA Astrophysics Data System (ADS)

Brillson, Leonard J.; Lu, Yicheng

2011-06-01

ZnO has emerged as a promising candidate for optoelectronic and microelectronic applications, whose development requires greater understanding and control of their electronic contacts. The rapid pace of ZnO research over the past decade has yielded considerable new information on the nature of ZnO interfaces with metals. Work on ZnO contacts over the past decade has now been carried out on high quality material, nearly free from complicating factors such as impurities, morphological and native point defects. Based on the high quality bulk and thin film crystals now available, ZnO exhibits a range of systematic interface electronic structure that can be understood at the atomic scale. Here we provide a comprehensive review of Schottky barrier and ohmic contacts including work extending over the past half century. For Schottky barriers, these results span the nature of ZnO surface charge transfer, the roles of surface cleaning, crystal quality, chemical interactions, and defect formation. For ohmic contacts, these studies encompass the nature of metal-specific interactions, the role of annealing, multilayered contacts, alloyed contacts, metallization schemes for state-of-the-art contacts, and their application to n-type versus p-type ZnO. Both ZnO Schottky barriers and ohmic contacts show a wide range of phenomena and electronic behavior, which can all be directly tied to chemical and structural changes on an atomic scale.

Challenges and Opportunities in Scaling-Up Nutrition in Healthcare

PubMed Central

Darnton-Hill, Ian; Samman, Samir

2015-01-01

Healthcare continues to be in a state of flux; conventionally, this provides opportunities and challenges. The opportunities include technological breakthroughs, improved economies and increasing availability of healthcare. On the other hand, economic disparities are increasing and leading to differing accessibility to healthcare, including within affluent countries. Nutrition has received an increase in attention and resources in recent decades, a lot of it stimulated by the rise in obesity, type 2 diabetes mellitus and hypertension. An increase in ageing populations also has meant increased interest in nutrition-related chronic diseases. In many middle-income countries, there has been an increase in the double burden of malnutrition with undernourished children and overweight/obese parents and adolescents. In low-income countries, an increased evidence base has allowed scaling-up of interventions to address under-nutrition, both nutrition-specific and nutrition-sensitive interventions. Immediate barriers (institutional, structural and biological) and longer-term barriers (staffing shortages where most needed and environmental impacts on health) are discussed. Significant barriers remain for the near universal access to healthcare, especially for those who are socio-economically disadvantaged, geographically isolated, living in war zones or where environmental damage has taken place. However, these barriers are increasingly being recognized, and efforts are being made to address them. The paper aims to take a broad view that identifies and then comments on the many social, political and scientific factors affecting the achievement of improved nutrition through healthcare. PMID:27417744

Impact of 1985 hurricanes on Isles Dernieres, Louisiana: Temporal and spatial analysis of coastal geomorphic changes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Debusshere, K.; Westphal, K.; Penland, S.

1989-09-01

Catastrophic geomorphic changes occurred in the Isles Dernieres barrier island arc as a result of the direct impact of three hurricanes in 1985. The severity of the impact of hurricanes Danny, Elena, and Juan had not been equaled since the landfall of hurricanes Betsy and Camille in the late 1960s. The Isles Dernieres had not been subjected to a direct hurricane landfall since hurricane Bob in 1979. The recent hurricane impacts provided the USGS/LGS Louisiana Cooperative Barrier Island and Land Loss Study the opportunity to examine the process-response characteristics of this low-profile transgressive barrier island arc to multiple hurricane impactsmore » in a single hurricane season. The geomorphic changes along the Isles Dernieres were determined using four sequential airborne videotape surveys acquired in July 1984, July 1985 (pre-storm), August 1985 (post-Danny) and November 1985 (post-Juan) and mapped on 1:24,000 base maps produced from concurrent vertical aerial photography. A coastal geomorphic classification was developed to describe, quantify, and map the alongshore geomorphic, sedimentologic , and vegetative character of this barrier shoreline. The classification consists of three levels of descriptors: (1) primary morphology to define the predominant longshore morphology, (2) modifiers to depict the small-scale longshore features, and (3) variants to locate and quantify important coastal features, not mappable at the scale used.« less

Development and validation of The Personal Diabetes Questionnaire (PDQ): a measure of diabetes self-care behaviors, perceptions and barriers.

PubMed

Stetson, Barbara; Schlundt, David; Rothschild, Chelsea; Floyd, Jennifer E; Rogers, Whitney; Mokshagundam, Sri Prakash

2011-03-01

To develop and evaluate the validity and reliability of The Personal Diabetes Questionnaire (PDQ), a brief, yet comprehensive measure of diabetes self-care behaviors, perceptions and barriers. To examine individual items to provide descriptive and normative information and provide data on scale reliability and associations between PDQ scales and concurrently assessed HBA(1c) and BMI. Items were written to address nutritional management, medication utilization, blood glucose monitoring, and physical activity. The initial instrument was reviewed by multidisciplinary diabetes care providers and items subsequently revised until the measure provided complete coverage of the diabetes care domains using as few items as possible. The scoring scheme was generated rationally. Subjects were 790 adults (205 with type 1 and 585 with type 2 diabetes) who completed the PDQ while waiting for clinic appointments. Item completion rates were high, with few items skipped by participants. Subscales demonstrated good internal consistency (Cronbach α=.650-.834) and demonstrated significant associations with BMI (p ≤.001) and HbA(1c) (p ≤.001). The PDQ is a useful measure of diabetes self-care behaviors and related perceptions and barriers that is reliable and valid and feasible to administer in a clinic setting. This measure may be used to obtain data for assessing diabetes self-management and barriers and to guide patient care. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Fragmentation reduces regional-scale spatial genetic structure in a wind-pollinated tree because genetic barriers are removed.

PubMed

Wang, Rong; Compton, Stephen G; Shi, Yi-Su; Chen, Xiao-Yong

2012-09-01

Gene flow strongly influences the regional genetic structuring of plant populations. Seed and pollen dispersal patterns can respond differently to the increased isolation resulting from habitat fragmentation, with unpredictable consequences for gene flow and population structuring. In a recently fragmented landscape we compared the pre- and post-fragmentation genetic structure of populations of a tree species where pollen and seed dispersal respond differentially to forest fragmentation generated by flooding. Castanopsis sclerophylla is wind-pollinated, with seeds that are dispersed by gravity and rodents. Using microsatellites, we found no significant difference in genetic diversity between pre- and post-fragmentation cohorts. Significant genetic structure was observed in pre-fragmentation cohorts, due to an unknown genetic barrier that had isolated one small population. Among post-fragmentation cohorts this genetic barrier had disappeared and genetic structure was significantly weakened. The strengths of genetic structuring were at a similar level in both cohorts, suggesting that overall gene flow of C. sclerophylla has been unchanged by fragmentation at the regional scale. Fragmentation has blocked seed dispersal among habitats, but this appears to have been compensated for by enhanced pollen dispersal, as indicated by the disappearance of a genetic barrier, probably as a result of increased wind speeds and easier pollen movement over water. Extensive pollen flow can counteract some negative effects of fragmentation and assist the long-term persistence of small remnant populations.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klaiman, Shachar; Gilary, Ido; Moiseyev, Nimrod

Analytical expressions for the resonances of the long-range potential (LRP), V(r)=a/r-b/r{sup 2}, as a function of the Hamiltonian parameters were derived by Doolen a long time ago [Int. J. Quant. Chem. 14, 523 (1979)]. Here we show that converged numerical results are obtained by applying the shifted complex scaling and the smooth-exterior scaling (SES) methods rather than the usual complex coordinate method (i.e., complex scaling). The narrow and broad shape-type resonances are shown to be localized inside or over the potential barrier and not inside the potential well. Therefore, the resonances for Doolen LRP's are not associated with the tunnelingmore » through the potential barrier as one might expect. The fact that the SES provides a universal reflection-free absorbing potential is, in particular, important in view of future applications. In particular, it is most convenient to calculate the molecular autoionizing resonances by adding one-electron complex absorbing potentials into the codes of the available quantum molecular electronic packages.« less

Broad Scale Monitoring in the US Forest Service: Institutional Challenges and Collaborative Opportunites for Improving Planning and Decision-Making in an Era of Climate Change

NASA Astrophysics Data System (ADS)

Wurtzebach, Z.

2016-12-01

In 2012, the United States Forest Service promulgated new rules to guide Forest planning efforts in accordance with the National Forest Management Act (NFMA). One important component of the 2012 rule is a requirement for Regionally coordinated cross-boundary "broad scale" monitoring strategies that are designed to inform and facilitate Forest-level adaptive management and planning. This presentation will examine institutional challenges and opportunites for developing effective broad scale monitoring strategies identified in 90 interviews with USFS staff and partner organizations, and collaborative workshops held in Colorado, Wyoming, Arizona, and New Mexico. Internal barriers to development include funding and human resource constraints, organizational culture, problematic incentives and accountability structures, data management issues, and administrative barriers to collaboration. However, we also identify several opportunities for leveraging interagency collaboration, facilitating multi-level coordination, generating efficiencies in data collection and analysis, and improving strategies for reporting and communication to Forest level decision-makers and relevant stakeholders.

Structural and electrical characterization of ultra-thin SrTiO3 tunnel barriers grown over YBa2Cu3O7 electrodes for the development of high Tc Josephson junctions.

PubMed

Félix, L Avilés; Sirena, M; Guzmán, L A Agüero; Sutter, J González; Vargas, S Pons; Steren, L B; Bernard, R; Trastoy, J; Villegas, J E; Briático, J; Bergeal, N; Lesueur, J; Faini, G

2012-12-14

The transport properties of ultra-thin SrTiO(3) (STO) layers grown over YBa(2)Cu(3)O(7) electrodes were studied by conductive atomic force microscopy at the nano-scale. A very good control of the barrier thickness was achieved during the deposition process. A phenomenological approach was used to obtain critical parameters regarding the structural and electrical properties of the system. The STO layers present an energy barrier of 0.9 eV and an attenuation length of 0.23 nm, indicating very good insulating properties for the development of high-quality Josephson junctions.

Spontaneously intermixed Al-Mg barriers enable corrosion-resistant Mg/SiC multilayer coatings

DOE PAGES

Soufli, Regina; Fernandez-Perea, Monica; Baker, Sherry L.; ...

2012-07-24

Magnesium/silicon carbide (Mg/SiC) has the potential to be the best-performing reflective multilayercoating in the 25–80 nm wavelength region but suffers from Mg-related corrosion, an insidious problem which completely degrades reflectance. We have elucidated the origins and mechanisms of corrosion propagation within Mg/SiC multilayers. Based on our findings, we have demonstrated an efficient and simple-to-implement corrosion barrier for Mg/SiC multilayers. In conclusion, the barrier consists of nanometer-scale Mg and Al layers that intermix spontaneously to form a partially amorphous Al-Mg layer and is shown to prevent atmospheric corrosion while maintaining the unique combination of favorable Mg/SiC reflective properties.

The cold and atmospheric-pressure air surface barrier discharge plasma for large-area sterilization applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang Dacheng; Department of Aeronautics, Fujian Key Laboratory for Plasma and Magnetic Resonance, School of Physics and Mechanical and Electrical Engineering, Xiamen University, Xiamen, Fujian 361005; Zhao Di

2011-04-18

This letter reports a stable air surface barrier discharge device for large-area sterilization applications at room temperature. This design may result in visually uniform plasmas with the electrode area scaled up (or down) to the required size. A comparison for the survival rates of Escherichia coli from air, N{sub 2} and O{sub 2} surface barrier discharge plasmas is presented, and the air surface plasma consisting of strong filamentary discharges can efficiently kill Escherichia coli. Optical emission measurements indicate that reactive species such as O and OH generated in the room temperature air plasmas play a significant role in the sterilizationmore » process.« less

Kinetics of polyelectrolyte adsorption

NASA Astrophysics Data System (ADS)

Cohen Stuart, M. A.; Hoogendam, C. W.; de Keizer, A.

1997-09-01

The kinetics of polyelectrolyte adsorption has been investigated theoretically. In analogy with Kramers' rate theory for chemical reactions we present a model which is based on the assumption that a polyelectrolyte encounters a barrier in its motion towards an adsorbing surface. The height of the barrier, which is of electrostatic origin, is calculated with a self-consistent-field (SCF) model. The salt concentration strongly affects the height of the barrier. At moderate salt concentrations (0953-8984/9/37/009/img1) equilibrium in the adsorption is attained; at low salt concentration (0953-8984/9/37/009/img2) equilibrium is not reached on the time scale of experiments. The attachment process shows resemblances to the classical DLVO theory.

Upper Temperature Limit of Environmental Barrier Coatings for Enabling Propulsion Materials Established

NASA Technical Reports Server (NTRS)

Lee, Kang N.; Fox, Dennis S.; Robinson, R. Craig

2001-01-01

Silicon-based ceramics, such as SiC/SiC composites and Si3N4, are the prime candidates for hot section structural components of next-generation gas turbines. A key barrier to such an application is the rapid recession of silicon-based ceramics in combustion environments because of the volatilization of silica scale by water vapor (refs. 1 and 2). Environmental barrier coatings (EBC's) were developed to prevent recession in the High Speed Research--Enabling Propulsion Materials (HSR-EPM) Program (refs. 3 and 4). An investigation under the Ultra-Efficient Engine Technology Program was undertaken at the NASA Glenn Research Center to establish the upper temperature limit of the EPM EBC.

Bathymetric comparisons adjacent to the Louisiana barrier islands: Processes of large-scale change

USGS Publications Warehouse

List, J.H.; Jaffe, B.E.; Sallenger, A.H.; Hansen, M.E.

1997-01-01

This paper summarizes the results of a comparative bathymetric study encompassing 150 km of the Louisiana barrier-island coast. Bathymetric data surrounding the islands and extending to 12 m water depth were processed from three survey periods: the 1880s, the 1930s, and the 1980s. Digital comparisons between surveys show large-scale, coherent patterns of sea-floor erosion and accretion related to the rapid erosion and disintegration of the islands. Analysis of the sea-floor data reveals two primary processes driving this change: massive longshore transport, in the littoral zone and at shoreface depths; and increased sediment storage in ebb-tidal deltas. Relative sea-level rise, although extraordinarily high in the study area, is shown to be an indirect factor in causing the area's rapid shoreline retreat rates.

Design and performance evaluation of a 1000-year evapotranspiration-capillary surface barrier

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Zhuanfang Fred; Strickland, Christopher E.; Link, Steven O.

Surface barrier technology is used to isolate radioactive waste and to reduce or eliminate recharge water to the waste zone for 1000 years or longer. However, the design and evaluation of such a barrier is challenging because of the extremely long design life. The Prototype Hanford Barrier (PHB) was designed as a 1000-year barrier with pre-determined design and performance objectives and demonstrated in field from 1994 to present. The barrier was tested to evaluate surface-barrier design and performance at the field scale under conditions of enhanced and natural precipitation and of no vegetation. The monitoring data demonstrate that the barriermore » satisfied nearly all key objectives. The PHB far exceeded the Resource Conservation and Recovery Act criteria, functioned in Hanford’s semiarid climate, limited drainage to well below the 0.5 mm yr-1 performance criterion, limited runoff, and minimized erosion. Given the two-decade record of successful performance and consideration of all the processes and mechanisms that could degrade the stability and hydrology in the future, the results suggest the PHB is very likely to perform for its 1000-year design life. This conclusion is based on two assumptions: (1) the exposed subgrade receives protection against erosion and (2) institutional controls prevent inadvertent human activity at the barrier. The PHB design can serve as the base for site-specific barriers over waste sites containing underground nuclear waste, uranium mine tailings, and hazardous mine waste.« less

Why do not more prisoners participate in adult education? An analysis of barriers to education in Norwegian prisons

NASA Astrophysics Data System (ADS)

Manger, Terje; Eikeland, Ole Johan; Asbjørnsen, Arve

2018-06-01

From a lifelong learning perspective, education during incarceration is crucial for prisoners' rehabilitation. This article describes the authors' development of their Perceived Barriers to Prison Education Scale (PBPES) and examines what deters prisoners from participating in education during their incarceration, how their perceptions differ depending on gender, age, educational level, learning difficulties, length of prison sentence, and whether the prisoners express a desire to participate in education or not. Within a larger survey conducted in all Norwegian prisons among all prisoners with Norwegian citizenship, the authors focused on those who did not participate in education (n = 838). To reveal the underlying constructs that comprise perceived barriers, they hypothesised a three-factor model to which they applied confirmatory factor analysis (CFA). The analysis confirmed the model, which comprised institutional barriers (e.g. insufficient practical arrangements; lack of access to computers and to the Internet), situational barriers (e.g. education is not considered to be of help in the current situation) and dispositional barriers (e.g. having difficulties in mathematics, reading, writing and concentrating), with good fit to the data. The authors used mixed-model analyses of variance to examine differences between subgroups of prisoners. Gender, age, educational level, learning difficulties and length of prison sentence were found to influence perceived barriers. The authors also observed that prisoners who wished to participate in education were more likely than others to perceive institutional barriers and less likely to perceive situational barriers.

Scaling laws for coastal overwash morphology

NASA Astrophysics Data System (ADS)

Lazarus, Eli D.

2016-12-01

Overwash is a physical process of coastal sediment transport driven by storm events and is essential to landscape resilience in low-lying barrier environments. This work establishes a comprehensive set of scaling laws for overwash morphology: unifying quantitative descriptions with which to compare overwash features by their morphological attributes across case examples. Such scaling laws also help relate overwash features to other morphodynamic phenomena. Here morphometric data from a physical experiment are compared with data from natural examples of overwash features. The resulting scaling relationships indicate scale invariance spanning several orders of magnitude. Furthermore, these new relationships for overwash morphology align with classic scaling laws for fluvial drainages and alluvial fans.

Understanding barriers to exercise implementation 5-year post-breast cancer diagnosis: a large-scale qualitative study.

PubMed

Hefferon, Kate; Murphy, Helen; McLeod, Janice; Mutrie, Nanette; Campbell, Anna

2013-10-01

Due to the amount of literature supporting exercise participation after cancer diagnosis, there has been recent interest in barriers to exercise engagement among cancer patients. However, little is known regarding reasons why people choose to disengage and how this disengagement occurs over time. This study aimed to qualitatively study the perceived barriers to exercise implementation, 5-year post-breast cancer diagnosis. Eighty-three female breast cancer survivors participated in a one-to-one semi-structured interview, regarding their experience of exercise over the past 5 years following their original participation in a group-based structured exercise intervention after diagnosis (41 from intervention and 42 from original control group). The data were analysed using inductive thematic analysis. The findings included three main themes and several subthemes regarding the women's perceived barriers: psychological barriers (lack of motivation, fears, dislike of gym, not being the 'sporty type'), physical barriers (the ageing process, cancer treatment and other physical co-morbidities, fatigue and weight gain) and contextual and environmental barriers (employment, traditional female care-giving roles, proximity/access to facilities, seasonal weather). The findings add inductive support to the current survivor health research advocating the use of activity immediately after diagnosis, as well as the need for tailored activity programmes in order to overcome potential obstacles.

Does self-compassion mitigate the relationship between burnout and barriers to compassion? A cross-sectional quantitative study of 799 nurses.

PubMed

Dev, Vinayak; Fernando, Antonio T; Lim, Anecita Gigi; Consedine, Nathan S

2018-05-01

Burnout has numerous negative consequences for nurses, potentially impairing their ability to deliver compassionate patient care. However, the association between burnout and compassion and, more specifically, barriers to compassion in medicine is unclear. This article evaluates the associations between burnout and barriers to compassion and examines whether dispositional self-compassion might mitigate this association. Consistent with prior work, the authors expected greater burnout to predict greater barriers to compassion. We also expected self-compassion - the ability to be kind to the self during times of distress - to weaken the association between burnout and barriers to compassion among nurses. Registered nurses working in New Zealand medical contexts were recruited using non-random convenience sampling. Following consent, 799 valid participants completed a cross-sectional survey including the Copenhagen Burnout Inventory, the Barriers to Physician Compassion scale, and a measure of dispositional self-compassion. As expected, greater burnout predicted greater barriers to compassion while self-compassion predicted fewer barriers. However, self-compassion mitigated the association between burnout and burnout related barriers to compassion (but not other barriers). The interaction suggested that suggested that the association was stronger (rather than weaker) among those with greater self-compassion. Understanding the lack of compassion and the effects of burnout in patient care are priorities in health. This report extends evidence on the association between burnout and compassion-fatigue to show that burnout also predicts the experience of specific barriers to compassion. While self-compassion predicted lower burnout and barriers, it may not necessarily reduce the extent to which burnout contributes to the experience of barriers to compassion in medicine. Implications for understanding how burnout manifests in barriers to clinical compassion, interventions and professional training, and future directions in nursing are discussed. Copyright © 2018 Elsevier Ltd. All rights reserved.

Barriers to global health development: An international quantitative survey.

PubMed

Weiss, Bahr; Pollack, Amie Alley

2017-01-01

Global health's goal of reducing low-and-middle-income country versus high-income country health disparities faces complex challenges. Although there have been discussions of barriers, there has not been a broad-based, quantitative survey of such barriers. 432 global health professionals were invited via email to participate in an online survey, with 268 (62%) participating. The survey assessed participants' (A) demographic and global health background, (B) perceptions regarding 66 barriers' seriousness, (C) detailed ratings of barriers designated most serious, (D) potential solutions. Thirty-four (of 66) barriers were seen as moderately or more serious, highlighting the widespread, significant challenges global health development faces. Perceived barrier seriousness differed significantly across domains: Resource Limitations mean = 2.47 (0-4 Likert scale), Priority Selection mean = 2.20, Corruption, Lack of Competence mean = 1.87, Social and Cultural Barriers mean = 1.68. Some system-level predictors showed significant but relatively limited relations. For instance, for Global Health Domain, HIV and Mental Health had higher levels of perceived Social and Cultural Barriers than other GH Domains. Individual-level global health experience predictors had small but significant effects, with seriousness of (a) Corruption, Lack of Competence, and (b) Priority Selection barriers positively correlated with respondents' level of LMIC-oriented (e.g., weeks/year spent in LMIC) but Academic Global Health Achievement (e.g., number of global health publications) negatively correlated with overall barrier seriousness. That comparatively few system-level predictors (e.g., Organization Type) were significant suggests these barriers may be relatively fundamental at the system-level. Individual-level and system-level effects do have policy implications; e.g., Priority Selection barriers were among the most serious, yet effects on seriousness of how LMIC-oriented a professional was versus level of academic global health achievement ran in opposite directions, suggesting increased discussion of priorities between LMIC-based and other professionals may be useful. It is hoped the 22 suggested solutions will provide useful ideas for addressing global health barriers.

Small-Scale Hydroelectric Power in the Southwest: New Impetus for an old Energy Source

NASA Astrophysics Data System (ADS)

1980-06-01

A forum was provided for state legislators and other interested persons to discuss the problems facing small scale hydro developers, and to recommend appropriate solutions to resolve those problems. Alternative policy options were recommended for consideration by both state and federal agencies. Emphasis was placed on the legal, institutional, environmental and economic barriers at the state level, as well as the federal delays associated with licensing small scale hydro projects. Legislative resolution of the problems and delays in small scale hydro licensing and development were also stressed.

Barriers to HIV care for women of color living in the Southeastern US are associated with physical symptoms, social environment, and self-determination.

PubMed

Toth, Matthew; Messer, Lynne C; Quinlivan, E Byrd

2013-11-01

HIV-infected women of color (WOC) face particular barriers to accessing HIV medical care. To understand the impact of physical symptoms, social support, and self-determination on barriers to care, we interviewed HIV-infected women of color. HIV-infected WOC (N=141), attending an academic infectious disease clinic for HIV care in North Carolina, completed the Barriers to Care scale and were categorized as reporting a history of low (less than four of eleven barriers) or high (five or more) barriers to care. Binomial regression was used to estimate prevalence ratios and risk differences of reported barriers to care and its correlates such as depression, anxiety, illness-severity, psychological abuse, social support, treatment-specific social support, and self-determination (autonomy, relatedness, competency). A lower risk of reporting five or more barriers to care was associated with higher levels of autonomy (PR=0.93, 95% CI: 0.89, 0.96), relatedness (PR=0.92, 95% CI: 0.89, 0.94), competency (PR=0.93, 95% CI: 0.87, 0.98), and social support (PR=0.24, 95% CI: 0.81, 0.81). Depression, illness severity, and psychological abuse were associated with a greater risk of having five or more barriers to care. There are multiple social and psychological factors that contribute to perceived barriers to HIV care among WOC in the southeastern USA. Interventions that promote social support and increase individual self-determination have the potential to improve access to HIV care for WOC.

Evaluating the long-term hydrology of an evapotranspiration-capillary barrier with a 1000 year design life

NASA Astrophysics Data System (ADS)

Zhang, Z. Fred

2016-06-01

A surface barrier is a commonly used technology for isolation of subsurface contaminants. Surface barriers for isolating radioactive waste are expected to perform for centuries to millennia, yet there are very few data for field-scale surface barriers for periods approaching a decade or longer. The Prototype Hanford Barrier (PHB) with a design life of 1000 years was constructed over an existing radioactive waste site in 1994 to demonstrate its long-term performance. The primary element of the PHB is an evapotranspiration-capillary (ETC) barrier in which precipitation water is stored in a fine-textured soil layer and later released to the atmosphere via evapotranspiration. To address the barrier performance under extreme conditions, this study included an enhanced precipitation stress test from 1995 to 1997 to determine barrier response to extreme precipitation events. During this period a 1000 year 24 h return rainstorm was simulated in March every year. The loss of vegetation on barrier hydrology was tested with a controlled fire test in 2008. The 19 year monitoring record shows that the store-and-release mechanism worked as well as or better than the design criterion. Average drainage from the ETC barrier amounted to an average of 0.005 mm yr-1, which is well below the design criterion of 0.5 mm yr-1. After a simulated wildfire, the naturally reestablished vegetation and increased evaporation combined to release the stored water and summer precipitation to the atmosphere such that drainage did not occur in the 5 years subsequent to the fire.

CMAS Degradation of Environmental Barrier Coatings: Mechanisms and Mitigation

DTIC Science & Technology

2013-09-30

enable it to grow an EBC-like scale , i.e. resistant to volatilization, when exposed directly to the oxidative environment at places where the original...CAD) methods. It was shown that formulations based on SiC/YB2/Y5Si3/AI203 produced scales with the desirable characteristics, comprising primarily...oxidizing surface, which could be desirable in crack healing scenarios but led to excessive thick scales . When density was improved by CAD the Y

Terawatt-scale photovoltaics: Trajectories and challenges

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haegel, Nancy M.; Margolis, Robert; Buonassisi, Tonio

The annual potential of solar energy far exceeds the world's total energy consumption. However, the vision of photovoltaics (PVs) providing a substantial fraction of global electricity generation and total energy demand is far from being realized. What technical, infrastructure, economic, and policy barriers need to be overcome for PVs to grow to the multiple terawatt (TW) scale? Here, we assess realistic future scenarios and make suggestions for a global agenda to move toward PVs at a multi-TW scale.

Terawatt-scale photovoltaics: Trajectories and challenges

DOE PAGES

Haegel, Nancy M.; Margolis, Robert; Buonassisi, Tonio; ...

2017-04-13

The annual potential of solar energy far exceeds the world's total energy consumption. However, the vision of photovoltaics (PVs) providing a substantial fraction of global electricity generation and total energy demand is far from being realized. What technical, infrastructure, economic, and policy barriers need to be overcome for PVs to grow to the multiple terawatt (TW) scale? Here, we assess realistic future scenarios and make suggestions for a global agenda to move toward PVs at a multi-TW scale.

The A14-scale: development and evaluation of a questionnaire for assessment of adherence and individual barriers.

PubMed

Jank, Susanne; Bertsche, Thilo; Schellberg, Dieter; Herzog, Wolfgang; Haefeli, Walter E

2009-08-01

To develop a questionnaire ("A14") for the description of adherence and individual barriers as basis for adherence-enhancing interventions in the clinical and pharmaceutical setting, and to compare it to the validated German MMAS (Morisky Medication Adherence Scale). Fourteen questions with a 5-item likert-scale from "never" (4) to "very often" (0) were given to 150 medical inpatients. According to their score, patients were classified into non-adherent (score <50) or adherent (score 50-56). On the dichotomous MMAS, "yes" is scored 0 and "no" 1 point, a total score of 4 indicating adherence. Patients with complete scales were compared with the remaining patients regarding socio-demographic factors. Descriptive statistics, Cronbach's Alpha, Spearman correlation, and kappa were computed. Eighty-three participants completed both scales. Patients with missing values differed significantly regarding age, education, and adherence according to MMAS. Cronbach's Alpha for A14 was 0.861. MMAS and A14 median total scores were 4 and 52, respectively. About 39.5% of patients were non-adherent as per MMAS compared to 40% as per A14; kappa was 0.262 (P = 0.016). The total scores correlated with a Rho-value of 0.43 (P < 0.001). The A14-scale showed good internal consistency and a significant correlation with the MMAS suggesting that it merits further investigation.

First-principles study of transition-metal nitrides as diffusion barriers against Al

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mei, Zhi-Gang; Yacout, Abdellatif M.; Kim, Yeon Soo

2016-04-01

Using density-functional theory based first-principles calculations we provided a comparative study of the diffusion barrier properties of TiN, ZrN, and HfN against Al for U-Mo dispersion fuel applications. We firstly examined the thermodynamic stability of these transition-metal nitrides with Al. The calculated heats of reaction show that both TiN and ZrN are thermodynamically unstable diffusion barrier materials, which might be decomposed by Al at relatively high temperatures. As a comparison, HfN is a stable diffusion barrier material for Al. To evaluate the kinetic stability of these nitride systems against Al diffusion, we investigated the diffusion mechanisms of Al in TiN,more » ZrN and HfN using atomic scale simulations. The effect of non-stoichiometry on the defect formation and Al migration was systematically studied. (C) 2015 ELSEVIER B.V. All rights reserved« less

Investigation of ionic transport in sodium scandium phosphate (NSP) and related compounds

NASA Astrophysics Data System (ADS)

Bhat, Kaustubh; Blügel, Stefan; Lustfeld, Hans

Sodium ionic conductors offer significant advantages for application in large scale energy storage systems. In this study, we investigate the different pathways available for sodium ion conduction in NSP and calculate energy barriers for ionic transport using Density Functional Theory (DFT) and the Nudged Elastic Band Method. We identify the structural parameters that reduce the energy barrier, by calculating the influence of positive and negative external pressure on the energy barrier. Lattice strain can be introduced by cation or anion substitution within the NASICON structure. We substitute the scandium atom with other trivalent atoms such as aluminium and yttrium, and calculate the resulting energy barriers. Sodium thiophosphate (Na3PS4) has previously shown about two orders of magnitude higher ionic conductivity than sodium phosphate (Na3PO4). We investigate the effect of substituting oxygen with sulphur in NSP. We acknowledge discussions with our experimental colleagues F. Tietz and M. Guin toward this work

Possible origin and roles of nano-porosity in ZrO2 scales for hydrogen pick-up in Zr alloys

NASA Astrophysics Data System (ADS)

Lindgren, Mikaela; Geers, Christine; Panas, Itai

2017-08-01

A mechanistic understanding of Wagnerian build-up and subsequent non-Wagnerian break-down of barrier oxide upon oxidation of zirconium alloys by water is reiterated. Hydrogen assisted build-up of nano-porosity is addressed. Growth of sub-nanometer wide stalactitic pores owing to increasing aggregation of neutral oxygen vacancies offering a means to permeate hydrogen into the alloy is explored by density functional theory. The Wagnerian channel utilizes charge separation allowing charged oxygen vacancies and electrons to move separately from nominal anode to nominal cathode. This process becomes increasingly controlled by the charging of the barrier oxide resulting in sub-parabolic rate law for oxide growth. The break-down of the barrier oxide is understood to be preceded by avalanching hydrogen pick-up in the alloy. Pore mediated diffusion allows water to effectively short circuit the barrier oxide.

Self-organization and forcing templates in coastal barrier response to storms

NASA Astrophysics Data System (ADS)

Lazarus, E.

2015-12-01

When a storm event pushes water up and over a coastal barrier, cross-shore flow transports sediment from the barrier face to the back-barrier environment. This natural physical process is called "overwash", and "washover" is the sedimentary deposit it forms. Overwash and washover support critical coastal habitats, and enable barriers to maintain their height and width relative to rising sea level. On developed barrier coasts, overwash constitutes a natural hazard, which sea-level rise will exacerbate. Overwash is also a prerequisite for barrier breaching and coastal flooding. Predicting occurrence and characteristics of overwash and washover has significant societal value. Hazard models typically assume that pre-storm barrier morphology determines how the barrier changes during a storm. However, classic work has documented the absence of a relationship between pre/post-storm topography in some cases, and has also identified rhythmic patterns in washover alongshore. Previous explanations for these spatial patterns have looked to forcing templates, forms that get imprinted in the barrier shape. An alternative explanation is that washover patterns self-organize, emerging from feedbacks between water flow and sediment transport. Self-organization and forcing templates are often framed as mutually exclusive, but patterns likely form across a continuum of conditions. Here, I use data from a new physical experiment to suggest that spatial patterns in washover can self-organize within the limit of a forcing template of some critical "strength", beyond which pre/post-storm morphologies are highly correlated. Quantifying spatial patterns in washover deposits opens exciting questions regarding coastal morphodynamic response to storms. Measurement of relative template strength over extended spatial (and temporal) scales has the potential to improve hazard assessment and prediction, particularly where template strength is low and self-organization dominates barrier change.

Design and performance evaluation of a 1000-year evapotranspiration-capillary surface barrier.

PubMed

Zhang, Zhuanfang Fred; Strickland, Christopher E; Link, Steven O

2017-02-01

Surface barrier technology is used to isolate radioactive waste and to reduce or eliminate recharge water to the waste zone for 1000 years or longer. However, the design and evaluation of such a barrier is challenging because of the extremely long design life. After establishing a set of design and performance objectives, a package of design solutions was developed for 1000-year surface barriers over nuclear waste sites. The Prototype Hanford Barrier (PHB) was then constructed in 1994 in the field over an existing waste site as a demonstration. The barrier was tested to evaluate surface-barrier design and performance at the field scale under conditions of enhanced and natural precipitation and of no vegetation. The monitoring data demonstrate that the barrier satisfied nearly all objectives in the past two decades. The PHB far exceeded the Resource Conservation and Recovery Act criteria, functioned in Hanford's semiarid climate, limited drainage to well below the 0.5 mm yr -1 performance criterion, limited runoff, and minimized erosion and bio-intrusion. Given the two-decade record of successful performance and consideration of the processes and mechanisms that could affect barrier stability and hydrology in the future, the results suggest the PHB is very likely to perform for its 1000-year design life. This conclusion is based on two assumptions: (1) the exposed subgrade receives protection against erosion and (2) institutional controls prevent inadvertent human activity at the barrier. The PHB design can serve as the basis for site-specific barriers over waste sites containing underground nuclear waste, uranium mine tailings, and hazardous mine waste. Copyright © 2016 Elsevier Ltd. All rights reserved.

Influence of the geometry of protective barriers on the propagation of shock waves

NASA Astrophysics Data System (ADS)

Sochet, I.; Eveillard, S.; Vinçont, J. Y.; Piserchia, P. F.; Rocourt, X.

2017-03-01

The protection of industrial facilities, classified as hazardous, against accidental or intentional explosions represents a major challenge for the prevention of personal injury and property damage, which also involves social and economic issues. We consider here the use of physical barriers against the effects of these explosions, which include the pressure wave, the projection of fragments and the thermal flash. This approach can be recommended for the control of major industrial risks, but no specific instructions are available for its implementation. The influence of a protective barrier against a detonation-type explosion is studied in small-scale experiments. The effects of overpressure are examined over the entire path of the shock wave across the barrier and in the downstream zone to be protected. Two series of barrier structures are studied. The first series (A) of experiments investigates two types of barrier geometry with dimensions based on NATO recommendations. These recommendations stipulate that the barrier should be 2 m higher than the charge height, the thickness at the crest should be more than 0.5 m, while its length should be equal to twice the protected structure length and the bank slope should be equivalent to the angle of repose of the soil. The second series (B) of experiments investigates the influence of geometrical parameters of the barrier (thickness at the crest and inclination angles of the front and rear faces) on its protective effects. This project leads to an advance in our understanding of the physical phenomena involved in the propagation of blast waves resulting from an external explosion, in the area around a protective physical barrier. The study focuses on the dimensioning of protective barriers against overpressure effects arising from detonation and shows the advantage of using a barrier with a vertical front or rear face.

Land-Based Wind Turbine Transportation and Logistics Barriers and Their Effects on U.S. Wind Markets (Presentation)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cotrell, J.; Stehly, T.; Johnson, J.

The average size of land based wind turbines installed in the United States has increased dramatically over time. As a result wind turbines are facing new transportation and logistics barriers that limit the size of utility scale land based wind turbines that can be deployed in the United States. Addressing these transportation and logistics barriers will allow for even further increases in U.S. turbine size using technologies under development for offshore markets. These barriers are important because larger taller turbines have been identified as a path to reducing the levelized cost of energy for electricity. Additionally, increases in turbine sizemore » enable the development of new low and moderate speed markets in the U.S. In turn, wind industry stakeholder support, market stability, and ultimately domestic content and manufacturing competitiveness are potentially affected. In general there is very little recent literature that characterizes transportation and logistics barriers and their effects on U.S. wind markets and opportunities. Accordingly, the objective of this paper is to report the results of a recent NREL study that identifies the barriers, assesses their impact and provides recommendations for strategies and specific actions.« less

Length-scale dependent transport properties of colloidal and protein solutions for prediction of crystal nucleation rates

NASA Astrophysics Data System (ADS)

Kalwarczyk, Tomasz; Sozanski, Krzysztof; Jakiela, Slawomir; Wisniewska, Agnieszka; Kalwarczyk, Ewelina; Kryszczuk, Katarzyna; Hou, Sen; Holyst, Robert

2014-08-01

We propose a scaling equation describing transport properties (diffusion and viscosity) in the solutions of colloidal particles. We apply the equation to 23 different systems including colloids and proteins differing in size (range of diameters: 4 nm to 1 μm), and volume fractions (10-3-0.56). In solutions under study colloids/proteins interact via steric, hydrodynamic, van der Waals and/or electrostatic interactions. We implement contribution of those interactions into the scaling law. Finally we use our scaling law together with the literature values of the barrier for nucleation to predict crystal nucleation rates of hard-sphere like colloids. The resulting crystal nucleation rates agree with existing experimental data.We propose a scaling equation describing transport properties (diffusion and viscosity) in the solutions of colloidal particles. We apply the equation to 23 different systems including colloids and proteins differing in size (range of diameters: 4 nm to 1 μm), and volume fractions (10-3-0.56). In solutions under study colloids/proteins interact via steric, hydrodynamic, van der Waals and/or electrostatic interactions. We implement contribution of those interactions into the scaling law. Finally we use our scaling law together with the literature values of the barrier for nucleation to predict crystal nucleation rates of hard-sphere like colloids. The resulting crystal nucleation rates agree with existing experimental data. Electronic supplementary information (ESI) available: Experimental and some analysis details. See DOI: 10.1039/c4nr00647j

Global report on preterm birth and stillbirth (4 of 7): delivery of interventions.

PubMed

Victora, Cesar G; Rubens, Craig E

2010-02-23

The efficacious interventions identified in the previous article of this report will fail unless they are delivered at high and equitable coverage. This article discusses critical delivery constraints and strategies. Achieving universal coverage entails addressing major barriers at many levels. An overarching constraint is the lack of political will, resulting from the dearth of preterm birth and stillbirth data and the lack of visibility. Other barriers exist at the household and community levels, such as insufficient demand for interventions or sociocultural barriers; at the health services level, such as a lack of resources and trained healthcare providers; and at the health sector policy and management level, such as poorly functioning, centralized systems. Additional constraints involve weak governance and accountability, political instability, and challenges in the physical environment. Scaling up maternal, newborn and child health interventions requires strengthening health systems, but there is also a role for focused, targeted interventions. Choosing a strategy involves identifying appropriate channels for reaching high coverage, which depends on many factors such as access to and attendance at healthcare facilities. Delivery channels vary, and may include facility- and community-based healthcare providers, mass media campaigns, and community-based approaches and marketing strategies. Issues related to scaling up are discussed in the context of four interventions that may be given to mothers at different stages throughout pregnancy or to newborns: (1) detection and treatment of syphilis; (2) emergency Cesarean section; (3) newborn resuscitation; and (4) kangaroo mother care. Systematic reviews of the literature and large-scale implementation studies are analyzed for each intervention. Equitable and successful scale-up of preterm birth and stillbirth interventions will require addressing multiple barriers, and utilizing multiple delivery approaches and channels. Another important need is developing strategies to discontinue ineffective or harmful interventions. Preterm birth and stillbirth interventions must also be placed in the broader maternal, newborn and child health context to identify and prioritize those that will help improve several outcomes at the same time. The next article discusses advocacy challenges and opportunities.

Tests of NASA ceramic thermal barrier coating for gas-turbine engines

NASA Technical Reports Server (NTRS)

Liebert, C. H.

1979-01-01

A two-layer thermal barrier coating system with a bond coating of nickel-chromium-aluminum-yttrium and a ceramic coating of yttria-stabilized zirconia was tested for corrosion protection, thermal protection and durability. Full-scale gas-turbine engine tests demonstrated that this coating eliminated burning, melting, and warping of uncoated parts. During cyclic corrosion resistance tests made in marine diesel fuel products of combustion in a burner rig, the ceramic cracked on some specimens. Metallographic examination showed no base metal deterioration.

Plasma sprayed ceramic thermal barrier coating for NiAl-based intermetallic alloys

NASA Technical Reports Server (NTRS)

Miller, Robert A. (Inventor); Doychak, Joseph (Inventor)

1994-01-01

A thermal barrier coating system consists of two layers of a zirconia-yttria ceramic. The first layer is applied by low pressure plasma spraying. The second layer is applied by conventional atmospheric pressure plasma spraying. This facilitates the attachment of a durable thermally insulating ceramic coating directly to the surface of a highly oxidation resistant NiAl-based intermetallic alloy after the alloy has been preoxidized to promote the formation of a desirable Al2O3 scale.

How soil moisture mediates the influence of transpiration on streamflow at hourly to interannual scales in a forested catchment

Treesearch

G.W. Moore; J.A. Jones; B.J. Bond

2011-01-01

The water balance equation dictates that streamflow may be reduced by transpiration. Yet temporal disequilibrium weakens the relationship between transpiration and streamflow in many cases where inputs and outputs are unbalanced. We address two critical knowledge barriers in ecohydrology with respect to time, scale dependence and lags. Study objectives were to...

Identifying the source of super-high energetic electrons in the presence of pre-plasma in laser–matter interaction at relativistic intensities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, D.; Krasheninnikov, S. I.; Luan, S. X.

The generation of super-high energetic electrons influenced by pre-plasma in relativistic intensity laser–matter interaction is studied in a one-dimensional slab approximation with particle-in-cell simulations. Different pre-plasma scale lengths and laser intensities are considered, showing an increase in both particle number and cut-off kinetic energy of electrons with the increase of pre-plasma scale length and laser intensity, the cut-off kinetic energy greatly exceeding the corresponding laser ponderomotive energy. A two-stage electron acceleration model is proposed to explain the underlying physics. The first stage is attributed to the synergetic acceleration by longitudinal electric field and counter-propagating laser pulses, and a scaling lawmore » is obtained with efficiency depending on the pre-plasma scale length and laser intensity. These electrons pre-accelerated in the first stage could build up an intense electrostatic potential barrier with maximal value several times as large as the initial electron kinetic energy. Some of the energetic electrons could be further accelerated by reflection off the electrostatic potential barrier, with their finial kinetic energies significantly higher than the values pre-accelerated in the first stage.« less

Identifying the source of super-high energetic electrons in the presence of pre-plasma in laser–matter interaction at relativistic intensities

DOE PAGES

Wu, D.; Krasheninnikov, S. I.; Luan, S. X.; ...

2016-10-03

The generation of super-high energetic electrons influenced by pre-plasma in relativistic intensity laser–matter interaction is studied in a one-dimensional slab approximation with particle-in-cell simulations. Different pre-plasma scale lengths and laser intensities are considered, showing an increase in both particle number and cut-off kinetic energy of electrons with the increase of pre-plasma scale length and laser intensity, the cut-off kinetic energy greatly exceeding the corresponding laser ponderomotive energy. A two-stage electron acceleration model is proposed to explain the underlying physics. The first stage is attributed to the synergetic acceleration by longitudinal electric field and counter-propagating laser pulses, and a scaling lawmore » is obtained with efficiency depending on the pre-plasma scale length and laser intensity. These electrons pre-accelerated in the first stage could build up an intense electrostatic potential barrier with maximal value several times as large as the initial electron kinetic energy. Some of the energetic electrons could be further accelerated by reflection off the electrostatic potential barrier, with their finial kinetic energies significantly higher than the values pre-accelerated in the first stage.« less

Leisure time physical activity participation in individuals with spinal cord injury in Malaysia: barriers to exercise.

PubMed

Mat Rosly, Maziah; Halaki, Mark; Hasnan, Nazirah; Mat Rosly, Hadi; Davis, Glen M; Husain, Ruby

2018-02-06

Cross-sectional. An epidemiological study describing leisure time physical activities (LTPA) and the associations of barriers, sociodemographic and injury characteristics to moderate-vigorous aerobic exercise participation among individuals with spinal cord injury (SCI) in a developing Southeast Asian country. SCI community in Malaysia. The study sample consisted of 70 participants with SCI. Questionnaires were distributed containing an abbreviated Physical Activity Scale for Individuals with Physical Disabilities (items 2-6) and the Barriers to Exercise Scale using a 5-tier Likert format. Statistical analyses were χ 2 tests, odds ratios, and binary forward stepwise logistic regression to assess the association and to predict factors related to participation in moderate-vigorous intensity aerobic exercise (items 4 and 5). Seventy-three percent of the study sample did not participate in any form of moderate or vigorous LTPA. The top three barriers to undertaking LTPA (strongly agree and agree descriptors) were expensive exercise equipment (54%), pain (37%) and inaccessible facilities (36%). Participants over the age of 35 years, ethnicity, health concerns, perceiving exercise as difficult and indicating lack of transport were significantly different (p < 0.05) between participation and non-participation in moderate-vigorous aerobic exercise type of LTPA. Age, ethnicity, indicated health concerns and lack of transport were the significant predictors in likelihood of participating in moderate-vigorous LTPA (p < 0.1). The issues raised depicted barriers within the intrapersonal (health concerns, exercising is too difficult, pain while exercising, age more than 35), interpersonal (different ethnicity), community (expensive exercise equipment), and policy levels (lack of or poor access to transportation, inaccessible facilities) that prevent LTPA participation.

Barrier Effect of the Indo-Pacific Maritime Continent on the MJO: Perspectives from Tracking MJO Precipitation

NASA Astrophysics Data System (ADS)

Zhang, C.; Ling, J.

2016-12-01

To advance the study of the barrier effect of the Indo-Pacific Maritime Continent (MC) on the MJO, we propose two criteria to judge explanations for this phenomenon. The first one is that such explanations should include specific features of the MC, namely, its intricate land-sea distributions and elevated terrains. The second is that they should include mechanisms for some MJO events to overcome the barrier effect as well as the barrier effect itself. Guided by these criteria, we have used a precipitation-tracking method to identify MJO events, distinguish those that propagate across the MC (MJO-C) from those that are blocked by the MC (MJO-B), and compare these two types of MJO events and their large-scale environments. The barrier effect cannot be explained in terms of the strength and horizontal scale or distributions of MJO convection as it approaches the MC from the Indian Ocean. A distinction between MJO-B and MJO-C is their ratios of precipitation over the sea vs. land in the MC. MJO events may propagate through the MC when their convection over the sea of the MC is sufficiently developed and dominates that over land. This may happen for two reasons. One is stronger precipitation over land that occurs before the arrival of MJO convection centers, which is assisted by greater low-level moisture flux convergence over the MC. This stronger "vanguard of precipitation" for MJO-C would make the ground wetter and thus reduce land-locked diurnal convection that has been proposed to be detrimental to MJO propagation through the MC. Another possible reason for the more vigorous development of MJO-C convection over the sea is higher SST in the MC before MJO convection centers enter the region.

Barriers to global health development: An international quantitative survey

PubMed Central

2017-01-01

Background Global health’s goal of reducing low-and-middle-income country versus high-income country health disparities faces complex challenges. Although there have been discussions of barriers, there has not been a broad-based, quantitative survey of such barriers. Methods 432 global health professionals were invited via email to participate in an online survey, with 268 (62%) participating. The survey assessed participants’ (A) demographic and global health background, (B) perceptions regarding 66 barriers’ seriousness, (C) detailed ratings of barriers designated most serious, (D) potential solutions. Results Thirty-four (of 66) barriers were seen as moderately or more serious, highlighting the widespread, significant challenges global health development faces. Perceived barrier seriousness differed significantly across domains: Resource Limitations mean = 2.47 (0–4 Likert scale), Priority Selection mean = 2.20, Corruption, Lack of Competence mean = 1.87, Social and Cultural Barriers mean = 1.68. Some system-level predictors showed significant but relatively limited relations. For instance, for Global Health Domain, HIV and Mental Health had higher levels of perceived Social and Cultural Barriers than other GH Domains. Individual–level global health experience predictors had small but significant effects, with seriousness of (a) Corruption, Lack of Competence, and (b) Priority Selection barriers positively correlated with respondents’ level of LMIC-oriented (e.g., weeks/year spent in LMIC) but Academic Global Health Achievement (e.g., number of global health publications) negatively correlated with overall barrier seriousness. Conclusions That comparatively few system-level predictors (e.g., Organization Type) were significant suggests these barriers may be relatively fundamental at the system-level. Individual-level and system-level effects do have policy implications; e.g., Priority Selection barriers were among the most serious, yet effects on seriousness of how LMIC-oriented a professional was versus level of academic global health achievement ran in opposite directions, suggesting increased discussion of priorities between LMIC-based and other professionals may be useful. It is hoped the 22 suggested solutions will provide useful ideas for addressing global health barriers. PMID:28972971

The saturated zone at Yucca Mountain: An overview of the characterization and assessment of the saturated zone as a barrier to potential radionuclide migration

USGS Publications Warehouse

Eddebbarh, A.-A.; Zyvoloski, G.A.; Robinson, B.A.; Kwicklis, E.M.; Reimus, P.W.; Arnold, B.W.; Corbet, T.; Kuzio, S.P.; Faunt, C.

2003-01-01

The US Department of Energy is pursuing Yucca Mountain, Nevada, for the development of a geologic repository for the disposal of spent nuclear fuel and high-level radioactive waste, if the repository is able to meet applicable radiation protection standards established by the US Nuclear Regulatory Commission and the US Environmental Protection Agency (EPA). Effective performance of such a repository would rely on a number of natural and engineered barriers to isolate radioactive waste from the accessible environment. Groundwater beneath Yucca Mountain is the primary medium through which most radionuclides might move away from the potential repository. The saturated zone (SZ) system is expected to act as a natural barrier to this possible movement of radionuclides both by delaying their transport and by reducing their concentration before they reach the accessible environment. Information obtained from Yucca Mountain Site Characterization Project activities is used to estimate groundwater flow rates through the site-scale SZ flow and transport model area and to constrain general conceptual models of groundwater flow in the site-scale area. The site-scale conceptual model is a synthesis of what is known about flow and transport processes at the scale required for total system performance assessment of the site. This knowledge builds on and is consistent with knowledge that has accumulated at the regional scale but is more detailed because more data are available at the site-scale level. The mathematical basis of the site-scale model and the associated numerical approaches are designed to assist in quantifying the uncertainty in the permeability of rocks in the geologic framework model and to represent accurately the flow and transport processes included in the site-scale conceptual model. Confidence in the results of the mathematical model was obtained by comparing calculated to observed hydraulic heads, estimated to measured permeabilities, and lateral flow rates calculated by the site-scale model to those calculated by the regional-scale flow model. In addition, it was confirmed that the flow paths leaving the region of the potential repository are consistent with those inferred from gradients of measured head and those independently inferred from water-chemistry data. The general approach of the site-scale SZ flow and transport model analysis is to calculate unit breakthrough curves for radionuclides at the interface between the SZ and the biosphere using the three-dimensional site-scale SZ flow and transport model. Uncertainties are explicitly incorporated into the site-scale SZ flow and transport abstractions through key parameters and conceptual models. ?? 2002 Elsevier Science B.V. All rights reserved.

Advanced Environmental Barrier Coatings Developed for SiC/SiC Composite Vanes

NASA Technical Reports Server (NTRS)

Lee, Kang N.; Fox, Dennis S.; Eldridge, Jeffrey I.; Zhu, Dongming; Bansal, Narottam P.; Miller, Robert A.

2003-01-01

Ceramic components exhibit superior high-temperature strength and durability over conventional component materials in use today, signifying the potential to revolutionize gas turbine engine component technology. Silicon-carbide fiber-reinforced silicon carbide ceramic matrix composites (SiC/SiC CMCs) are prime candidates for the ceramic hotsection components of next-generation gas turbine engines. A key barrier to the realization of SiC/SiC CMC hot-section components is the environmental degradation of SiC/SiC CMCs in combustion environments. This is in the form of surface recession due to the volatilization of silica scale by water vapor. An external environmental barrier coating (EBC) is a logical approach to achieve protection and long-term durability.

Tunneling rates in electron transport through double-barrier molecular junctions in a scanning tunneling microscope

PubMed Central

Nazin, G. V.; Wu, S. W.; Ho, W.

2005-01-01

The scanning tunneling microscope enables atomic-scale measurements of electron transport through individual molecules. Copper phthalocyanine and magnesium porphine molecules adsorbed on a thin oxide film grown on the NiAl(110) surface were probed. The single-molecule junctions contained two tunneling barriers, vacuum gap, and oxide film. Differential conductance spectroscopy shows that electron transport occurs via vibronic states of the molecules. The intensity of spectral peaks corresponding to the individual vibronic states depends on the relative electron tunneling rates through the two barriers of the junction, as found by varying the vacuum gap tunneling rate by changing the height of the scanning tunneling microscope tip above the molecule. A simple, sequential tunneling model explains the observed trends. PMID:15956189

Tunneling rates in electron transport through double-barrier molecular junctions in a scanning tunneling microscope.

PubMed

Nazin, G V; Wu, S W; Ho, W

2005-06-21

The scanning tunneling microscope enables atomic-scale measurements of electron transport through individual molecules. Copper phthalocyanine and magnesium porphine molecules adsorbed on a thin oxide film grown on the NiAl(110) surface were probed. The single-molecule junctions contained two tunneling barriers, vacuum gap, and oxide film. Differential conductance spectroscopy shows that electron transport occurs via vibronic states of the molecules. The intensity of spectral peaks corresponding to the individual vibronic states depends on the relative electron tunneling rates through the two barriers of the junction, as found by varying the vacuum gap tunneling rate by changing the height of the scanning tunneling microscope tip above the molecule. A simple, sequential tunneling model explains the observed trends.

Hydrodynamic optical soliton tunneling

NASA Astrophysics Data System (ADS)

Sprenger, P.; Hoefer, M. A.; El, G. A.

2018-03-01

A notion of hydrodynamic optical soliton tunneling is introduced in which a dark soliton is incident upon an evolving, broad potential barrier that arises from an appropriate variation of the input signal. The barriers considered include smooth rarefaction waves and highly oscillatory dispersive shock waves. Both the soliton and the barrier satisfy the same one-dimensional defocusing nonlinear Schrödinger (NLS) equation, which admits a convenient dispersive hydrodynamic interpretation. Under the scale separation assumption of nonlinear wave (Whitham) modulation theory, the highly nontrivial nonlinear interaction between the soliton and the evolving hydrodynamic barrier is described in terms of self-similar, simple wave solutions to an asymptotic reduction of the Whitham-NLS partial differential equations. One of the Riemann invariants of the reduced modulation system determines the characteristics of a soliton interacting with a mean flow that results in soliton tunneling or trapping. Another Riemann invariant yields the tunneled soliton's phase shift due to hydrodynamic interaction. Soliton interaction with hydrodynamic barriers gives rise to effects that include reversal of the soliton propagation direction and spontaneous soliton cavitation, which further suggest possible methods of dark soliton control in optical fibers.

Erosion and deterioration of the Isles Dernieres Barrier Island Arc, Louisiana, U.S.A.: 1853 to 1988

USGS Publications Warehouse

McBride, Randolph A.; Penland, Shea; Jaffe, Bruce E.; Williams, S. Jeffress; Sallenger, Asbury H.; Westphal, Karen A.

1989-01-01

Using cartographic and aerial photography data from the years 1853, 1890, 1934, 1956, 1978, 1984, and 1988, shoreline change maps of the Isles Dernieres barrier island arc were constructed. These data were accurately superimposed, using a computer mapping system, which removed projection, datum, scale, and other cartographic inconsistencies. Linear, areal, and perimeter measurements indicate that the Isles Dernieres are suffering rapid rates of coastal erosion, land loss, and breakup. Bayside and gulfside erosion, in combination with sediment shortage and subsidence, have caused the Isles Dernieres to narrow through time. In addition, the core of the barrier island arc does not migrate landward and instead, breaks up in place as a result of inlet breaching and development. This is in contrast to other models of landward barrier island migration during transgression. If these trends continue, the Isles Dernieres will likely evolve into a subaqueous inner-shelf shoal by the early 21st century. Loss of the Isles Dernieres barrier island arc will severely impact the Terrebonne parish estuary, resulting in decreased environmental quality and increased public risk from storms and hurricanes.

Hydrodynamic optical soliton tunneling.

PubMed

Sprenger, P; Hoefer, M A; El, G A

2018-03-01

A notion of hydrodynamic optical soliton tunneling is introduced in which a dark soliton is incident upon an evolving, broad potential barrier that arises from an appropriate variation of the input signal. The barriers considered include smooth rarefaction waves and highly oscillatory dispersive shock waves. Both the soliton and the barrier satisfy the same one-dimensional defocusing nonlinear Schrödinger (NLS) equation, which admits a convenient dispersive hydrodynamic interpretation. Under the scale separation assumption of nonlinear wave (Whitham) modulation theory, the highly nontrivial nonlinear interaction between the soliton and the evolving hydrodynamic barrier is described in terms of self-similar, simple wave solutions to an asymptotic reduction of the Whitham-NLS partial differential equations. One of the Riemann invariants of the reduced modulation system determines the characteristics of a soliton interacting with a mean flow that results in soliton tunneling or trapping. Another Riemann invariant yields the tunneled soliton's phase shift due to hydrodynamic interaction. Soliton interaction with hydrodynamic barriers gives rise to effects that include reversal of the soliton propagation direction and spontaneous soliton cavitation, which further suggest possible methods of dark soliton control in optical fibers.

Changes to zooplankton community structure following colonization of a small lake by Leptodora kindti

USGS Publications Warehouse

McNaught, A.S.; Kiesling, R.L.; Ghadouani, A.

2004-01-01

The predaceous cladoceran Leptodora kindti (Focke) became established in Third Sister Lake, Michigan, after individuals escaped from experimental enclosures in 1987. By 1988, the Leptodora population exhibited seasonal dynamics characteristic of natural populations. The maximum seasonal abundance of Leptodora increased to 85 individuals m-3 3 yr following the introduction. After the appearance of Leptodora, small-bodied cladocerans (Ceriodaphnia and Bosmina) virtually disappeared from the lake. There were strong seasonal shifts in the dominance patterns of both cladocerans and copepods, and Daphnia species diversity increased. Results from this unplanned introduction suggest that invertebrate predators can have a rapid and lasting effect on prey populations, even in the presence of planktivorous fish. Small-scale (<20 km) geographic barriers might be as important as large-scale barriers to dispersal of planktonic animals.

Biomimetic nanocoatings with exceptional mechanical, barrier, and flame-retardant properties from large-scale one-step coassembly

PubMed Central

Ding, Fuchuan; Liu, Jingjing; Zeng, Songshan; Xia, Yan; Wells, Kacie M.; Nieh, Mu-Ping; Sun, Luyi

2017-01-01

Large-scale biomimetic organic/inorganic hybrid nanocoatings with a nacre-like microstructure were prepared via a facile coassembly process. Different from conventional polymer nanocomposites, these nanocoatings contain a high concentration of nanosheets, which can be well aligned along the substrate surface. Moreover, the nanosheets and polymer matrix can be chemically co–cross-linked. As a result, the nanocoatings exhibit exceptional mechanical properties (high stiffness and strength), barrier properties (to both oxygen and water vapor), and flame retardancy, but they are also highly transparent (maintaining more than 85% of their original transmittance to visible light). The nanocoatings can be applied to various substrates and regular or irregular surfaces (for example, films and foams). Because of their excellent performance and high versatility, these nanocoatings are expected to find widespread application. PMID:28776038

Spectroscopic measurement of spin-dependent resonant tunneling through a 3D disorder: the case of MnAs/GaAs/MnAs junctions.

PubMed

Garcia, V; Jaffrès, H; George, J-M; Marangolo, M; Eddrief, M; Etgens, V H

2006-12-15

We propose an analytical model of spin-dependent resonant tunneling through a 3D assembly of localized states (spread out in energy and in space) in a barrier. An inhomogeneous distribution of localized states leads to resonant tunneling magnetoresistance inversion and asymmetric bias dependence as evidenced with a set of experiments with MnAs/GaAs(7-10 nm)/MnAs tunnel junctions. One of the key parameters of our theory is a dimensionless critical exponent beta scaling the typical extension of the localized states over the characteristic length scale of the spatial distribution function. Furthermore, we demonstrate, through experiments with localized states introduced preferentially in the middle of the barrier, the influence of an homogeneous distribution on the spin-dependent transport properties.

Population genomic analysis suggests strong influence of river network on spatial distribution of genetic variation in invasive saltcedar across the southwestern United States

USGS Publications Warehouse

Lee, Soo-Rang; Jo, Yeong-Seok; Park, Chan-Ho; Friedman, Jonathan M.; Olson, Matthew S.

2018-01-01

Understanding the complex influences of landscape and anthropogenic elements that shape the population genetic structure of invasive species provides insight into patterns of colonization and spread. The application of landscape genomics techniques to these questions may offer detailed, previously undocumented insights into factors influencing species invasions. We investigated the spatial pattern of genetic variation and the influences of landscape factors on population similarity in an invasive riparian shrub, saltcedar (Tamarix L.) by analysing 1,997 genomewide SNP markers for 259 individuals from 25 populations collected throughout the southwestern United States. Our results revealed a broad-scale spatial genetic differentiation of saltcedar populations between the Colorado and Rio Grande river basins and identified potential barriers to population similarity along both river systems. River pathways most strongly contributed to population similarity. In contrast, low temperature and dams likely served as barriers to population similarity. We hypothesize that large-scale geographic patterns in genetic diversity resulted from a combination of early introductions from distinct populations, the subsequent influence of natural selection, dispersal barriers and founder effects during range expansion.

A Resonant Tunneling Nanowire Field Effect Transistor with Physical Contractions: A Negative Differential Resistance Device for Low Power Very Large Scale Integration Applications

NASA Astrophysics Data System (ADS)

Molaei Imen Abadi, Rouzbeh; Saremi, Mehdi

2018-02-01

In this paper, the influence of ultra-scaled physical symmetrical contraction on electrical characteristics of ultra-thin silicon-on-insulator nanowires with circular gate-all-around structure is investigated by using a 3D Atlas numerical quantum simulator based on non-equilibrium green's function formalism. It is demonstrated that local cross-section variation in a nanowire transistor results in the establishment of tunnel energy barriers at the source-channel and drain-channel junctions which change device physics and cause a transmission from a quantum wire (1-D) to a floating quantum dot nanowire (0-D) introducing a resonant tunneling nanowire FET (RT-NWFET) as an interesting concept of nanoscale MOSFETs. The barriers construct resonance energy levels in the channel region of nanowires because of the longitudinal confinement in three directions causing some fluctuation in I D- V GS characteristic. In addition, these barriers remarkably improve the subthreshold swing and minimize the ON/OFF-current ratio degradation at a low operation voltage of 0.5 V. As a result, RT-NWFETs are intrinsically preserved from drain-source tunneling and are an interesting candidate for developing the roadmap below 10 nm.

Interplay of non-Markov and internal friction effects in the barrier crossing kinetics of biopolymers: insights from an analytically solvable model.

PubMed

Makarov, Dmitrii E

2013-01-07

Conformational rearrangements in biomolecules (such as protein folding or enzyme-ligand binding) are often interpreted in terms of low-dimensional models of barrier crossing such as Kramers' theory. Dimensionality reduction, however, entails memory effects; as a result, the effective frictional drag force along the reaction coordinate nontrivially depends on the time scale of the transition. Moreover, when both solvent and "internal" friction effects are important, their interplay results in a highly nonlinear dependence of the effective friction on solvent viscosity that is not captured by common phenomenological models of barrier crossing. Here, these effects are illustrated using an analytically solvable toy model of an unstructured polymer chain involved in an inter- or intramolecular transition. The transition rate is calculated using the Grote-Hynes and Langer theories, which--unlike Kramers' theory--account for memory. The resulting effective frictional force exerted by the polymer along the reaction coordinate can be rationalized in terms of the effective number of monomers engaged in the transition. Faster transitions (relative to the polymer reconfiguration time scale) involve fewer monomers and, correspondingly, lower friction forces, because the polymer chain does not have enough time to reconfigure in response to the transition.

Institutional stakeholder perceptions of barriers to addiction treatment under Mexico's drug policy reform.

PubMed

Werb, Dan; Strathdee, Steffanie A; Meza, Emilo; Rangel Gomez, Maria Gudelia; Palinkas, Lawrence; Medina-Mora, Maria Elena; Beletsky, Leo

2017-05-01

Mexico has experienced disproportionate drug-related harms given its role as a production and transit zone for illegal drugs destined primarily for the USA. In response, in 2009, the Mexican federal government passed legislation mandating pre-arrest diversion of drug-dependent individuals towards addiction treatment. However, this federal law was not specific about how the scale-up of the addiction treatment sector was to be operationalised. We therefore conducted in-depth qualitative interviews with key 'interactors' in fields affected by the federal legislation, including participants from the law enforcement, public health, addiction treatment, and governmental administration sectors. Among 19 participants from the municipal, state and federal levels were interviewed and multiple barriers to policy reform were identified. First, there is a lack of institutional expertise to implement the reform. Second, the operationalisation of the reform was not accompanied by a coordinated action plan. Third, the law is an unfunded mandate. Institutional barriers are likely hampering the implementation of Mexico's policy reform. Addressing the concerns expressed by interactors through the scale-up of services, the provision of increased training and education programmes for stakeholders and a coordinated action plan to operationalise the policy reform are likely needed to improve the policy reform process.

Barriers to involvement in physical activities of persons with mental illness.

PubMed

Shor, Ron; Shalev, Anat

2016-03-01

Participating in physical activities could be essential for reducing the multiple risk factors for health problems that persons with severe mental illness (SMI) may suffer. However, people with SMI are significantly less active than the general population. To develop knowledge about factors related to the perceived barriers hindering this population's participation in physical activities and the benefits this participation would have, a study was conducted in Israel with 86 people with mental illness living in community mental health facilities prior to their participation in a health promotion program. A mixed method was implemented and included: a scale designed to measure participants' perceptions of the barriers to and benefits of involvement in physical activities; instruments focusing on bio-psycho-social factors that may affect the level of barriers experienced; and personal interviews. The findings revealed high ranking for accessibility barriers hindering the participation in physical activities. Bio-psycho-social factors stemming from the participants' mental health, such as level of depression, were correlated with higher ranking of accessibility barriers. Bio-psycho-social factors reflecting positive mental health and health, such as positive appraisal of body weight, were correlated with lower ranking of accessibility barriers. Other barriers may include organizational and broader systemic barriers in the mental health facilities where the participants reside. These findings illuminate the need to consider the unique challenges that persons with mental illness may face in any attempt to advance their involvement in physical activity. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Perceived barriers to pediatrician and family practitioner participation in pediatric clinical trials: Findings from the Clinical Trials Transformation Initiative.

PubMed

Greenberg, Rachel G; Corneli, Amy; Bradley, John; Farley, John; Jafri, Hasan S; Lin, Li; Nambiar, Sumathi; Noel, Gary J; Wheeler, Chris; Tiernan, Rosemary; Smith, P Brian; Roberts, Jamie; Benjamin, Daniel K

2018-03-01

Despite legislation to stimulate pediatric drug development through clinical trials, enrolling children in trials continues to be challenging. Non-investigator (those who have never served as a clinical trial investigator) providers are essential to recruitment of pediatric patients, but little is known regarding the specific barriers that limit pediatric providers from participating in and referring their patients to clinical trials. We conducted an online survey of pediatric providers from a wide variety of practice types across the United States to evaluate their attitudes and awareness of pediatric clinical trials. Using a 4-point Likert scale, providers described their perception of potential barriers to their practice serving as a site for pediatric clinical trials. Of the 136 providers surveyed, 52/136 (38%) had previously referred a pediatric patient to a trial, and only 17/136 (12%) had ever been an investigator for a pediatric trial. Lack of awareness of existing pediatric trials was a major barrier to patient referral by providers, in addition to consideration of trial risks, distance to the site, and time needed to discuss trial participation with parents. Overall, providers perceived greater challenges related to parental concerns and parent or child logistical barriers than study implementation and ethics or regulatory barriers as barriers to their practice serving as a trial site. Providers who had previously been an investigator for a pediatric trial were less likely to be concerned with potential barriers than non-investigators. Understanding the barriers that limit pediatric providers from collaboration or inhibit their participation is key to designing effective interventions to optimize pediatric trial participation.

Participation of chronic patients in medical consultations: patients' perceived efficacy, barriers and interest in support.

PubMed

Henselmans, Inge; Heijmans, Monique; Rademakers, Jany; van Dulmen, Sandra

2015-12-01

Chronic patients are increasingly expected to participate actively in medical consultations. This study examined (i) patients' perceived efficacy and barriers to participation in consultations, (ii) patients' interest in communication support and (iii) correlates of perceived efficacy and barriers, with an emphasis on differences across providers' disciplines. A representative panel of chronic patients (n = 1314) filled out the short Perceived Efficacy in Patient-Provider Interaction scale and were questioned about barriers to participation and interest in communication support. Potential correlates included socio-demographic (age, sex, education, living situation), clinical (discipline care provider, type of illness, comorbidity, illness duration, functional disabilities, health consultations in last year) and personal characteristics (information preference, health literacy, level of general patient activation). Most patients felt efficacious in consultations, although 46% reported barriers to participation and 39% had an interest in support. Barriers most frequently recognized were 'not wanting to be bothersome', 'perception there is too little time' and 'remembering subjects only afterwards'. Patients most frequently endorsed relatively simple support. Patients perceived the least barriers and were least likely to endorse support when seeing a nurse. In multivariate models, consistent risk factors for low efficacy and perceived barriers were low health literacy and a low general patient activation. Many chronically ill patients feel confident in medical interactions. Still, a significant number might benefit from support. Often this concerned more generally vulnerable patients, that is, the low literate and generally less activated. Relatively simple supportive interventions are likely to be endorsed and might overcome frequent barriers. © 2014 John Wiley & Sons Ltd.

Perceived Exercise Benefits and Barriers of Non-Exercising Female University Students in the United Kingdom

PubMed Central

Lovell, Geoff P; Ansari, Walid El; Parker, John K

2010-01-01

Many individuals do not engage in sufficient physical activity due to low perceived benefits and high perceived barriers to exercise. Given the increasing incidence of obesity and obesity related health disorders, this topic requires further exploration. We used the Exercise Benefits/Barriers Scale to assess perceived benefit and barrier intensities to exercise in 200 non-exercising female university students (mean age 19.3 years, SD = 1.06) in the UK. Although our participants were selected because they self reported themselves to be non-exercising, however they reported significantly higher perceived benefits from exercise than perceived barriers to exercise [t(199) = 6.18, p < 0.001], and their perceived benefit/barrier ratio was 1.33. The greatest perceived benefit from exercise was physical performance followed by the benefits of psychological outlook, preventive health, life enhancement, and then social interaction. Physical performance was rated significantly higher than all other benefits. Psychological outlook and preventive health were not rated significantly different, although both were significantly higher than life enhancement and social interaction. Life enhancement was also rated significantly higher than social interaction. The greatest perceived barrier to exercise was physical exertion, which was rated significantly higher than time expenditure, exercise milieu, and family discouragement barriers. Implications from this investigation for the design of physical activity programmes include the importance, for females, of a perception of high benefit/barrier ratio that could be conducive to participation in exercise. Applied interventions need to assist female students to ‘disengage’ from or overcome any perceived ‘unpleasantness’ of physical exertion during physical activity (decrease their perceived barriers), and to further highlight the multiple health and other benefits of regular exercising (increase their perceived benefits). PMID:20617003

Barriers to implementing infection prevention and control guidelines during crises: experiences of health care professionals.

PubMed

Timen, Aura; Hulscher, Marlies E J L; Rust, Laura; van Steenbergen, Jim E; Akkermans, Reinier P; Grol, Richard P T M; van der Meer, Jos W M

2010-11-01

Communicable disease crises can endanger the health care system and often require special guidelines. Understanding reasons for nonadherence to crisis guidelines is needed to improve crisis management. We identified and measured barriers and conditions for optimal adherence as perceived by 4 categories of health care professionals. In-depth interviews were performed (n = 26) to develop a questionnaire for a cross-sectional survey of microbiologists (100% response), infection preventionists (74% response), public health physicians (96% response), and public health nurses (82% response). The groups were asked to appraise barriers encountered during 4 outbreaks (severe acute respiratory syndrome [SARS], Clostridium difficile ribotype 027, rubella, and avian influenza) according to a 5-point Likert scale. When at least 33% of the participants responded "strongly agree," "agree," or "rather agree than disagree," a barrier was defined as "often experienced." The common ("generic") barriers were included in a univariate and multivariate model. Barriers specific to the various groups were studied as well. Crisis guidelines were found to have 4 generic barriers to adherence: (1) lack of imperative or precise wording, (2) lack of easily identifiable instructions specific to each profession, (3) lack of concrete performance targets, and (4) lack of timely and adequate guidance on personal protective equipment and other safety measures. The cross-sectional study also yielded profession-specific sets of often-experienced barriers. To improve adherence to crisis guidelines, the generic barriers should be addressed when developing guidelines, irrespective of the infectious agent. Profession-specific barriers require profession-specific strategies to change attitudes, ensure organizational facilities, and provide an adequate setting for crisis management. Copyright © 2010 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.

Study of Barrier to Help Seeking and its Relationships with Disability in Patients with Headache.

PubMed

John, Deepa; Ram, Dushad; Sundarmurthy, Harsha; Rathod, Harshal; Rathod, Snehal

2016-10-01

Headache is among the first three most prevalent disorders with a wide treatment gap due to barriers in help seeking. Headache has been associated with disability. However, the relationship of barriers to help-seeking and disability are unexplored. To find out the barriers to help seeking and its relationship with headache related disability in patients with headache. In this hospital based cross-sectional study, 200 consecutive subjects with headache attending a tertiary care centre were recruited as per selection criteria and assessed with Sociodemographic & Clinical Proforma, Mini International Neuropsychiatric Interview (MINI), Barriers to Help Seeking Scale (BHSS), The Henry Ford Hospital Headache Disability Inventory (HDI). High mean score was observed on BHSS subscale need for control and self reliance (19.45; SD ±9.66) and minimizing problem and resignation (10.02; SD ±6.98). Mean score on the HDI was 25.65 (SD ± 14.09). Socioeconomic status of the patient was statistically significant and positively associated with need for control and self reliance (p=0.035), concrete barriers and distrust of care givers (p=0.039), emotional control (p=0.005), and privacy (p=0.002). Occupational status had significant association with need for control and self-reliance (p=0.01), minimizing problem and resignation (p=0.033), and emotional control (p=0.006). Score on hospital headache disability inventory significantly predicted the value of score on concrete barriers and distrust of caregivers domain of HDI (p=0.001). Autonomy and under estimation of seriousness of headache are common barriers to help seeking. Pattern of help seeking barriers may vary with socio-economic status and occupational status, while disability varies with gender and severity of headache. Headache associated disability is positively associated with concrete barriers.

Perceived exercise benefits and barriers of non-exercising female university students in the United Kingdom.

PubMed

Lovell, Geoff P; El Ansari, Walid; Parker, John K

2010-03-01

Many individuals do not engage in sufficient physical activity due to low perceived benefits and high perceived barriers to exercise. Given the increasing incidence of obesity and obesity related health disorders, this topic requires further exploration. We used the Exercise Benefits/Barriers Scale to assess perceived benefit and barrier intensities to exercise in 200 non-exercising female university students (mean age 19.3 years, SD = 1.06) in the UK. Although our participants were selected because they self reported themselves to be non-exercising, however they reported significantly higher perceived benefits from exercise than perceived barriers to exercise [t(199) = 6.18, p < 0.001], and their perceived benefit/barrier ratio was 1.33. The greatest perceived benefit from exercise was physical performance followed by the benefits of psychological outlook, preventive health, life enhancement, and then social interaction. Physical performance was rated significantly higher than all other benefits. Psychological outlook and preventive health were not rated significantly different, although both were significantly higher than life enhancement and social interaction. Life enhancement was also rated significantly higher than social interaction. The greatest perceived barrier to exercise was physical exertion, which was rated significantly higher than time expenditure, exercise milieu, and family discouragement barriers. Implications from this investigation for the design of physical activity programmes include the importance, for females, of a perception of high benefit/barrier ratio that could be conducive to participation in exercise. Applied interventions need to assist female students to 'disengage' from or overcome any perceived 'unpleasantness' of physical exertion during physical activity (decrease their perceived barriers), and to further highlight the multiple health and other benefits of regular exercising (increase their perceived benefits).

Barriers to use of information and computer technology by Australia's nurses: a national survey.

PubMed

Eley, Robert; Fallon, Tony; Soar, Jeffrey; Buikstra, Elizabeth; Hegney, Desley

2009-04-01

To support policy planning for health, the barriers to the use of health information and computer technology (ICT) by nurses in Australia were determined. Australia, in line with many countries, aims to achieve a better quality of care and health outcomes through effective and innovative use of health information. Nurses form the largest component of the health workforce. Successful adoption of ICT by nurses will be a requirement for success. No national study has been undertaken to determine the barriers to adoption. A self-administered postal survey was conducted. A questionnaire was distributed to 10,000 members of the Australian Nursing Federation. Twenty possible barriers to the use of health ICT uptake were offered and responses were given on a five point Likert scale. Work demands, access to computers and lack of support were the principal barriers faced by nurses to their adoption of the technology in the workplace. Factors that were considered to present few barriers included age and lack of interest. While age was not considered by the respondents to be a barrier, their age was positively correlated with several barriers, including knowledge and confidence in the use of computers. Results indicate that to use the information and computer technologies being brought into health care fully, barriers that prevent the principal users from embracing those technologies must be addressed. Factors such as the age of the nurse and their level of job must be considered when developing strategies to overcome barriers. The findings of the present study provide essential information not only for national government and state health departments but also for local administrators and managers to enable clinical nurses to meet present and future job requirements.

Geomorphology and depositional sub-environments of Assateague Island MD/VA

USGS Publications Warehouse

Morton, Robert A.; Bracone, Jeremy E.; Cooke, Brian

2007-01-01

The U.S. Geological Survey is studying coastal hazards and coastal change to improve our understanding of coastal ecosystems and to develop better capabilities of predicting future coastal change. One approach to understanding the dynamics of coastal systems is to monitor changes in barrier-island sub-environments through time. This involves examining morphological and topographic change at time scales ranging from millennia to years and space scales ranging from tens of kilometers to meters. Of particular interest are the processes that produce those changes and determining whether or not those processes are likely to persist into the future. In these analyses of hazards and change, both natural and anthropogenic influences are considered. Quantifying past magnitudes and rates of coastal change and knowing the principal factors that govern those changes are critical to predicting what changes are likely to occur under different scenarios, such as short-term impacts of extreme storms or long-term impacts of sea-level rise. Assateague Island MD/VA was selected for detailed mapping of barrier island morphology and topography because the island offers a diversity of depositional sub-environments that are representative of other barrier islands along the middle Atlantic coast. The geomorphology and sub-environment map emphasizes the origins of the surficial features and it also serves as a basis for documenting which sub-environments are relatively stable, such as the barrier island core, and those that are highly dynamic, such as the beach and active overwash zones.

Influencing physiotherapy student attitudes toward exercise for adolescents with Down syndrome.

PubMed

Shields, Nora; Bruder, Andrea; Taylor, Nicholas; Angelo, Tom

2011-01-01

Negative attitudes of physiotherapists may prevent them from implementing exercise as an intervention among people with disabilities. The aim of this study was to examine whether physiotherapy student attitudes towards the barriers to exercise for adolescents with Down syndrome changed as a result of participating in a 10-week exercise programme. Data were collected as part of a randomised controlled trial. Twenty physiotherapy students (2 men, 18 women; mean age 19.5±1.3 years) volunteered to act as mentors. Each mentor was matched with an adolescent with Down syndrome from the same metropolitan suburb, who had been randomly allocated to either the intervention or the control group. The 10 adolescents and students in the intervention group all completed a 10-week, twice a week progressive resistance exercise training programme. The 10 adolescents and students in the control group continued with their usual activities. The students completed the 18-item Exercise Barriers Scale at baseline and after 10 weeks. There was a positive change in attitudes, significant at the p <0.05 level, favouring the intervention group on 9 of the 18 items on the Exercise Barriers Scale. After engagement in a 10-week exercise programme with an adolescent with Down syndrome, physiotherapy students identified fewer barriers that would prevent adolescents with Down syndrome from exercising. Results indicate that contact with adolescents with Down syndrome during clinical placement can positively influence attitudes towards exercise for people with Down syndrome among physiotherapy students.

Is the number and size of scales in Liolaemus lizards driven by climate?

PubMed

José Tulli, María; Cruz, Félix B

2018-05-03

Ectothermic vertebrates are sensitive to thermal fluctuations in the environments where they occur. To buffer these fluctuations, ectotherms use different strategies, including the integument, which is a barrier that minimizes temperature exchange between the inner body and the surrounding air. In lizards, this barrier is constituted by keratinized scales of variable size, shape and texture, and its main function is protection, water loss avoidance and thermoregulation. The size of scales in lizards has been proposed to vary in relation to climatic gradients; however, it has also been observed that in some groups of Iguanian lizards could be related to phylogeny. Thus, here, we studied the area and number of scales (dorsal and ventral) of 61 species of Liolaemus lizards distributed in a broad latitudinal and altitudinal gradient to determine the nature of the variation of the scales with climate, and found that the number and size of scales are related to climatic variables, such as temperature and geographical variables as altitude. The evolutionary process that better explained how these morphological variables evolved was the Ornstein-Uhlenbeck model. The number of scales seemed to be related to common ancestry, whereas dorsal and ventral scale areas seemed to vary as a consequence of ecological traits. In fact, the ventral area is less exposed to climate conditions such as ultraviolet radiation or wind and is thus under less pressure to change in response to alterations in external conditions. It is possible that scale ornamentation such as keels and granulosity may bring some more information in this regard. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

High-Quality Charter Schools at Scale in Big Cities: Results of a Symposium (Seattle, Washington, January 20, 2006)

ERIC Educational Resources Information Center

Harvey, James; Rainey, Lydia

2006-01-01

Bringing charters to scale remains a major challenge. To learn more about barriers to the expansion of high-quality public charter schools and how they might be removed, the National Charter School Research Project (NCSRP) at the University of Washington and the National Alliance for Public Charter Schools convened a meeting of leaders from…

Proxy records of Holocene storm events in coastal barrier systems: Storm-wave induced markers

NASA Astrophysics Data System (ADS)

Goslin, Jérôme; Clemmensen, Lars B.

2017-10-01

Extreme storm events in the coastal zone are one of the main forcing agents of short-term coastal system behavior. As such, storms represent a major threat to human activities concentrated along the coasts worldwide. In order to better understand the frequency of extreme events like storms, climate science must rely on longer-time records than the century-scale records of instrumental weather data. Proxy records of storm-wave or storm-wind induced activity in coastal barrier systems deposits have been widely used worldwide in recent years to document past storm events during the last millennia. This review provides a detailed state-of-the-art compilation of the proxies available from coastal barrier systems to reconstruct Holocene storm chronologies (paleotempestology). The present paper aims (I) to describe the erosional and depositional processes caused by storm-wave action in barrier and back-barrier systems (i.e. beach ridges, storm scarps and washover deposits), (ii) to understand how storm records can be extracted from barrier and back-barrier sedimentary bodies using stratigraphical, sedimentological, micro-paleontological and geochemical proxies and (iii) to show how to obtain chronological control on past storm events recorded in the sedimentary successions. The challenges that paleotempestology studies still face in the reconstruction of representative and reliable storm-chronologies using these various proxies are discussed, and future research prospects are outlined.

Government chief nursing officers' perceptions of barriers to using research on staffing.

PubMed

Baernholdt, M; Lang, N M

2007-03-01

Current global healthcare problems include nursing shortages contributing to low nurse staffing. Low nurse staffing is associated with poor patient and nurse outcomes, but research utilization using these findings especially at the policy level remains slow. To assess high-ranking government nurses' perceptions of barriers to using research on nurse staffing. An electronic information message about the impact of nurse staffing was presented to government chief nursing officers (CNOs) from 110 countries. The CNOs' perceptions of local barriers to utilizing these research findings were then assessed in an electronic survey. The four factors that influence the first two stages of Rogers's five-stage model of diffusion were examined. The factors, characteristics of the adopter, organization, innovation and communication, were measured using an adapted version of the BARRIERS scale. Barriers were present in all four characteristics. The top barrier was lack of reports and studies in one place. Other barriers were lack of cooperation within the organization and lack of awareness of the research findings. Differences according to Gross National Income were also noted. The CNOs and other health policy advisors can use the findings in planning for adequate nurse staffing. Development of electronic newsletters with summaries of pertinent research for CNOs and other policy advisors is needed. Future studies on nurse staffing are warranted. They should focus on other settings and how best to share research findings with policymakers.

200-BP-1 Prototype Hanford Barrier -- 15 Years of Performance Monitoring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ward, Anderson L.; Draper, Kathryn E.; Link, Steven O.

2011-09-30

Monitoring is an essential component of engineered barrier system design and operation. A composite capacitive cover, including a capillary break and an evapotranspiration (ET) barrier at the Hanford Site, is generating data that can be used to help resolve these issues. The prototype Hanford barrier was constructed over the 216-B-57 Crib in 1994 to evaluate surface-barrier constructability, construction costs, and physical and hydrologic performance at the field scale. The barrier has been routinely monitored between November 1994 and September 1998 as part of a Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) treatability test of barrier performance formore » the 200 BP 1 Operable Unit. Since FY 1998, monitoring has focused on a more limited set of key water balance, stability, and biotic parameters. In FY 2009, data collection was focused on: (1) water-balance monitoring, consisting of precipitation, runoff, soil moisture storage, and drainage measurements with evapotranspiration calculated by difference; (2) stability monitoring, consisting of asphalt-layer-settlement, basalt-side-slope-stability, and surface-elevation measurements; (3) vegetation dynamics; and (4) animal use. September 2009 marked 15 years since the start of monitoring and the collection of performance data. This report describes the results of monitoring activities during the period October 1, 2008, through September 30, 2009, and summarizes the 15 years of performance data collected from September 1994 through September 2009.« less

Factors related to environmental barriers experienced by persons with and without disabilities in diverse African settings.

PubMed

Visagie, Surona; Eide, Arne H; Dyrstad, Karin; Mannan, Hasheem; Swartz, Leslie; Schneider, Marguerite; Mji, Gubela; Munthali, Alister; Khogali, Mustafa; van Rooy, Gert; Hem, Karl-Gerhard; MacLachlan, Malcolm

2017-01-01

This paper explores differences in experienced environmental barriers between individuals with and without disabilities and the impact of additional factors on experienced environmental barriers. Data was collected in 2011-2012 by means of a two-stage cluster sampling and comprised 400-500 households in different sites in South Africa, Sudan Malawi and Namibia. Data were collected through self-report survey questionnaires. In addition to descriptive statistics and simple statistical tests a structural equation model was developed and tested. The combined file comprised 9,307 participants. The Craig Hospital Inventory of Environmental Factors was used to assess the level of environmental barriers. Transportation, the natural environment and access to health care services created the biggest barriers. An exploratory factor analysis yielded support for a one component solution for environmental barriers. A scale was constructed by adding the items together and dividing by number of items, yielding a range from one to five with five representing the highest level of environmental barriers and one the lowest. An overall mean value of 1.51 was found. Persons with disabilities scored 1.66 and persons without disabilities 1.36 (F = 466.89, p < .001). Bivariate regression analyses revealed environmental barriers to be higher among rural respondents, increasing with age and severity of disability, and lower for those with a higher level of education and with better physical and mental health. Gender had an impact only among persons without disabilities, where women report more barriers than men. Structural equation model analysis showed that socioeconomic status was significantly and negatively associated with environmental barriers. Activity limitation is significantly associated with environmental barriers when controlling for a number of other individual characteristics. Reducing barriers for the general population would go some way to reduce the impact of these for persons with activity limitations, but additional and specific adaptations will be required to ensure an inclusive society.

Classification of the alterations of beaver dams to headwater streams in northeastern Connecticut, U.S.A.

NASA Astrophysics Data System (ADS)

Burchsted, Denise; Daniels, Melinda D.

2014-01-01

Of the many types of barriers to water flow, beaver dams are among the smallest, typically lasting less than a decade and rarely exceeding 1.5 m in height. They are also among the most frequent and common obstructions in rivers, with a density often exceeding ten dams per km, a frequency of construction within a given network on a time scale of years, and a historic extent covering most of North America. Past quantification of the geomorphologic impact of beaver dams has primarily been limited to local impacts within individual impoundments and is of limited geographic scope. To assess the impact of beaver dams at larger scales, this study examines channel shape and sediment distribution in thirty river reaches in northeastern Connecticut, U.S.A. The study reaches fall within the broader categories of impounded and free-flowing segments, leaving a third segment class of beaver meadows requiring additional study. Each of the study reaches were classified at the reach scale as free-flowing, valley-wide beaver pond, in-channel beaver pond, and downstream of beaver dam. The bankfull channel width to depth ratios and channel widths normalized by watershed area vary significantly across the study reach classes. Additionally, reaches modified by beaver dams have finer sediment distributions. This paper provides the first quantitative geomorphic descriptions of the in-channel beaver pond and reaches downstream of beaver dams. Given the different channel shapes and sediment distributions, we infer that geomorphic processes are longitudinally decoupled by these frequent barriers that control local base level. These barriers generate heterogeneity within a river network by greatly increasing the range of channel morphology and by generating patches controlled by different processes. Therefore, in spite of the small size of individual beaver dams, the cumulative effect of multiple dams has the potential to modify processes at larger spatial scales. To improve assessment of the larger-scale impacts, we propose a hierarchical classification scheme based on discontinuities, place the reach classes of this study within that scheme, and suggest that further research should continue investigation of discontinuity at the network scale and quantification of the cumulative impacts.

Mechanistic insights into heterogeneous methane activation

DOE PAGES

Latimer, Allegra A.; Aljama, Hassan; Kakekhani, Arvin; ...

2017-01-11

While natural gas is an abundant chemical fuel, its low volumetric energy density has prompted a search for catalysts able to transform methane into more useful chemicals. This search has often been aided through the use of transition state (TS) scaling relationships, which estimate methane activation TS energies as a linear function of a more easily calculated descriptor, such as final state energy, thus avoiding tedious TS energy calculations. It has been shown that methane can be activated via a radical or surface-stabilized pathway, both of which possess a unique TS scaling relationship. Herein, we present a simple model tomore » aid in the prediction of methane activation barriers on heterogeneous catalysts. Analogous to the universal radical TS scaling relationship introduced in a previous publication, we show that a universal TS scaling relationship that transcends catalysts classes also seems to exist for surface-stabilized methane activation if the relevant final state energy is used. We demonstrate that this scaling relationship holds for several reducible and irreducible oxides, promoted metals, and sulfides. By combining the universal scaling relationships for both radical and surface-stabilized methane activation pathways, we show that catalyst reactivity must be considered in addition to catalyst geometry to obtain an accurate estimation for the TS energy. Here, this model can yield fast and accurate predictions of methane activation barriers on a wide range of catalysts, thus accelerating the discovery of more active catalysts for methane conversion.« less

Mechanistic insights into heterogeneous methane activation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Latimer, Allegra A.; Aljama, Hassan; Kakekhani, Arvin

While natural gas is an abundant chemical fuel, its low volumetric energy density has prompted a search for catalysts able to transform methane into more useful chemicals. This search has often been aided through the use of transition state (TS) scaling relationships, which estimate methane activation TS energies as a linear function of a more easily calculated descriptor, such as final state energy, thus avoiding tedious TS energy calculations. It has been shown that methane can be activated via a radical or surface-stabilized pathway, both of which possess a unique TS scaling relationship. Herein, we present a simple model tomore » aid in the prediction of methane activation barriers on heterogeneous catalysts. Analogous to the universal radical TS scaling relationship introduced in a previous publication, we show that a universal TS scaling relationship that transcends catalysts classes also seems to exist for surface-stabilized methane activation if the relevant final state energy is used. We demonstrate that this scaling relationship holds for several reducible and irreducible oxides, promoted metals, and sulfides. By combining the universal scaling relationships for both radical and surface-stabilized methane activation pathways, we show that catalyst reactivity must be considered in addition to catalyst geometry to obtain an accurate estimation for the TS energy. Here, this model can yield fast and accurate predictions of methane activation barriers on a wide range of catalysts, thus accelerating the discovery of more active catalysts for methane conversion.« less

Predicting habits of vegetable parenting practices to facilitate the design of change programmes.

PubMed

Baranowski, Tom; Chen, Tzu-An; O'Connor, Teresia M; Hughes, Sheryl O; Diep, Cassandra S; Beltran, Alicia; Brand, Leah; Nicklas, Theresa; Baranowski, Janice

2016-08-01

Habit has been defined as the automatic performance of a usual behaviour. The present paper reports the relationships of variables from a Model of Goal Directed Behavior to four scales in regard to parents' habits when feeding their children: habit of (i) actively involving child in selection of vegetables; (ii) maintaining a positive vegetable environment; (iii) positive communications about vegetables; and (iv) controlling vegetable practices. We tested the hypothesis that the primary predictor of each habit variable would be the measure of the corresponding parenting practice. Internet survey data from a mostly female sample. Primary analyses employed regression modelling with backward deletion, controlling for demographics and parenting practices behaviour. Houston, Texas, USA. Parents of 307 pre-school (3-5-year-old) children. Three of the four models accounted for about 50 % of the variance in the parenting practices habit scales. Each habit scale was primarily predicted by the corresponding parenting practices scale (suggesting validity). The habit of active child involvement in vegetable selection was also most strongly predicted by two barriers and rudimentary self-efficacy; the habit of maintaining a positive vegetable environment by one barrier; the habit of maintaining positive communications about vegetables by an emotional scale; and the habit of controlling vegetable practices by a perceived behavioural control scale. The predictiveness of the psychosocial variables beyond parenting practices behaviour was modest. Discontinuing the habit of ineffective controlling parenting practices may require increasing the parent's perceived control of parenting practices, perhaps through simulated parent-child interactions.

Dependence of Ozone Generation on Gas Temperature Distribution in AC Atmospheric Pressure Dielectric Barrier Discharge in Oxygen

NASA Astrophysics Data System (ADS)

Takahashi, Go; Akashi, Haruaki

AC atmospheric pressure multi-filament dielectric barrier discharge in oxygen has been simulated using two dimensional fluid model. In the discharge, three kinds of streamers have been obtained. They are primary streamers, small scale streamers and secondary streamers. The primary streamers are main streamers in the discharge and the small scale streamers are formed after the ceasing of the primary streamers. And the secondary streamers are formed on the trace of the primary streamers. In these streamers, the primary and the small scale streamers are very effective to generate O(3P) oxygen atoms which are precursor of ozone. And the ozone is generated mainly in the vicinity of the dielectrics. In high gas temperature region, ozone generation decreases in general. However, increase of the O(3P) oxygen atom density in high gas temperature region compensates decrease of ozone generation rate coefficient. As a result, amount of ozone generation has not changed. But if the effect of gas temperature was neglected, amount of ozone generation increases 10%.

Nonlocal transport in the presence of transport barriers

NASA Astrophysics Data System (ADS)

Del-Castillo-Negrete, D.

2013-10-01

There is experimental, numerical, and theoretical evidence that transport in plasmas can, under certain circumstances, depart from the standard local, diffusive description. Examples include fast pulse propagation phenomena in perturbative experiments, non-diffusive scaling in L-mode plasmas, and non-Gaussian statistics of fluctuations. From the theoretical perspective, non-diffusive transport descriptions follow from the relaxation of the restrictive assumptions (locality, scale separation, and Gaussian/Markovian statistics) at the foundation of diffusive models. We discuss an alternative class of models able to capture some of the observed non-diffusive transport phenomenology. The models are based on a class of nonlocal, integro-differential operators that provide a unifying framework to describe non- Fickian scale-free transport, and non-Markovian (memory) effects. We study the interplay between nonlocality and internal transport barriers (ITBs) in perturbative transport including cold edge pulses and power modulation. Of particular interest in the nonlocal ``tunnelling'' of perturbations through ITBs. Also, flux-gradient diagrams are discussed as diagnostics to detect nonlocal transport processes in numerical simulations and experiments. Work supported by the US Department of Energy.

Non-linear, non-monotonic effect of nano-scale roughness on particle deposition in absence of an energy barrier: Experiments and modeling

PubMed Central

Jin, Chao; Glawdel, Tomasz; Ren, Carolyn L.; Emelko, Monica B.

2015-01-01

Deposition of colloidal- and nano-scale particles on surfaces is critical to numerous natural and engineered environmental, health, and industrial applications ranging from drinking water treatment to semi-conductor manufacturing. Nano-scale surface roughness-induced hydrodynamic impacts on particle deposition were evaluated in the absence of an energy barrier to deposition in a parallel plate system. A non-linear, non-monotonic relationship between deposition surface roughness and particle deposition flux was observed and a critical roughness size associated with minimum deposition flux or “sag effect” was identified. This effect was more significant for nanoparticles (<1 μm) than for colloids and was numerically simulated using a Convective-Diffusion model and experimentally validated. Inclusion of flow field and hydrodynamic retardation effects explained particle deposition profiles better than when only the Derjaguin-Landau-Verwey-Overbeek (DLVO) force was considered. This work provides 1) a first comprehensive framework for describing the hydrodynamic impacts of nano-scale surface roughness on particle deposition by unifying hydrodynamic forces (using the most current approaches for describing flow field profiles and hydrodynamic retardation effects) with appropriately modified expressions for DLVO interaction energies, and gravity forces in one model and 2) a foundation for further describing the impacts of more complicated scales of deposition surface roughness on particle deposition. PMID:26658159

Non-linear, non-monotonic effect of nano-scale roughness on particle deposition in absence of an energy barrier: Experiments and modeling

NASA Astrophysics Data System (ADS)

Jin, Chao; Glawdel, Tomasz; Ren, Carolyn L.; Emelko, Monica B.

2015-12-01

Deposition of colloidal- and nano-scale particles on surfaces is critical to numerous natural and engineered environmental, health, and industrial applications ranging from drinking water treatment to semi-conductor manufacturing. Nano-scale surface roughness-induced hydrodynamic impacts on particle deposition were evaluated in the absence of an energy barrier to deposition in a parallel plate system. A non-linear, non-monotonic relationship between deposition surface roughness and particle deposition flux was observed and a critical roughness size associated with minimum deposition flux or “sag effect” was identified. This effect was more significant for nanoparticles (<1 μm) than for colloids and was numerically simulated using a Convective-Diffusion model and experimentally validated. Inclusion of flow field and hydrodynamic retardation effects explained particle deposition profiles better than when only the Derjaguin-Landau-Verwey-Overbeek (DLVO) force was considered. This work provides 1) a first comprehensive framework for describing the hydrodynamic impacts of nano-scale surface roughness on particle deposition by unifying hydrodynamic forces (using the most current approaches for describing flow field profiles and hydrodynamic retardation effects) with appropriately modified expressions for DLVO interaction energies, and gravity forces in one model and 2) a foundation for further describing the impacts of more complicated scales of deposition surface roughness on particle deposition.

Assessing Controls on the Geometry and Dimensions of Modern Barrier Islands

NASA Astrophysics Data System (ADS)

Mulhern, J.; Johnson, C. L.; Martin, J. M.

2015-12-01

Barrier islands are highly ephemeral features, shaped by wave, tide, and storm energy. The processes that govern the size, shape, and motion of barrier islands are not well constrained, yet central to coastal dynamics. While the global distribution of barrier islands has been mapped and assessed, there is little consensus on the forces controlling barrier island formation, motion, or preservation. This study presents a new semi-global database of modern barrier islands to better understand their morphology and spatial distribution. We have mapped, in Google Earth, the subaerial extent of >350 barrier islands and spits, measuring spatial characteristic such as exposed area, perimeter, length, and width. These objects are cross-referenced with parameters that potentially control morphology, including tidal range, wave height, climate, distance from the continental shelf, proximity to fluvial output, and tectonic setting. This approach provides a more optimal framework to assess controls on coastal features, including barrier island morphology, and to investigate potential geometric scaling relationships. Preliminary analysis shows trends in the spatial characteristics of barrier islands. There is a strong linear relationship between the perimeter and length (y= -0.59 + 0.42x, R2=0.95). Linear trends also relate length to area when the data are separated by tidal range to wave height ratio. Assessment of barrier island shape supports the hypothesis of Hayes (1979) that barrier islands in wave-dominated settings are long and linear while those in mixed energy setting are more rounded. The barrier islands of the Texas Gulf of Mexico are larger than the global average for the database, with distinctly longer length values (41.16 km vs. 15.77 km respectively) and larger areas (103.81 km2 vs. 42.14 km2 respectively). Initial assessment shows that tidal range and wave height are primary controls barrier island dimensions. Future work will consider climate, latitude, fluvial input, and tectonic regime as additional factors. Assessing modern barrier islands will lend insight into potential paleomorphodynamic relationships and help determine how islands are transferred into the rock record, with implications for sequence stratigraphy, subsurface reservoirs, etc.

Barriers, Benefits, and Behaviors Related to Breakfast Consumption Among Rural Adolescents.

PubMed

Hearst, Mary O; Shanafelt, Amy; Wang, Qi; Leduc, Robert; Nanney, Marilyn S

2016-03-01

We sought to determine if perceived barriers, benefits, and modifiable behaviors support or interfere with breakfast consumption in a racially and economically diverse rural high school population. The participants were 832 Minnesota adolescents from 16 rural high schools. We used baseline data from a group randomized trial aimed at increasing school breakfast participation through policy and environmental-level school changes. Students completed an online survey asking about demographics, breakfast eating behaviors, and the barriers and benefits of eating as it relates to school performance. Bivariate and multivariate logistic regression, accounting for clustering by school, was performed using SAS. Each scale was modeled independently. Participants were 9th and 10th grade students, 36% free/reduced-price lunch (FRL), 30% non-White, and 55% female. Breakfast skippers compared to nonbreakfast skippers reported fewer school related benefits and beliefs and more barriers to eating breakfast (p < .01). Adjusted models revealed students reported more positive beliefs (OR = 0.78, 95% CI = 0.73-0.83), more benefits (OR = 0.95, 95% CI = 0.93-0.97) and fewer barriers (OR = 0.85, 95% CI = 0.82-0.87) and were less likely to skip breakfast. Future intervention research should focus on alleviating barriers and enhancing education around the school related benefits of eating breakfast. © 2016, American School Health Association.

An assessment of the barriers to accessing the Basic Package of Health Services (BPHS) in Afghanistan: was the BPHS a success?

PubMed

Frost, Alexandra; Wilkinson, Matthew; Boyle, Peter; Patel, Preeti; Sullivan, Richard

2016-11-15

Afghanistan is one of the most fragile and conflict-affected countries in the world. It has experienced almost uninterrupted conflict for the last thirty years, with the present conflict now lasting over a decade. With no history of a functioning healthcare system, the creation of the Basic Package of Health Services (BPHS) in 2003 was a response to Afghanistan's dire health needs following decades of war. Its objective was to provide a bare minimum of essential health services, which could be scaled up rapidly through contracting mechanisms with Non-Governmental Organisations (NGOs). The central thesis of this article is that, despite the good intentions of the BPHS, not enough has been done to overcome the barriers to accessing its services. This analysis, enabled through a review of the existing literature, identifies and categorises these barriers into the three access dimensions of: acceptability, affordability and availability. As each of these is explored individually, analysis will show the extent to which these barriers to access are a critical issue, consider the underlying reasons for their existence and evaluate the efforts to overcome these barriers. Understanding these barriers and the policies that have been implemented to address them is critical to the future of health system strengthening in Afghanistan.

Saudi high school students' attitudes and barriers toward the use of computer technologies in learning English.

PubMed

Sabti, Ahmed Abdulateef; Chaichan, Rasha Sami

2014-01-01

This study examines the attitudes of Saudi Arabian high school students toward the use of computer technologies in learning English. The study also discusses the possible barriers that affect and limit the actual usage of computers. Quantitative approach is applied in this research, which involved 30 Saudi Arabia students of a high school in Kuala Lumpur, Malaysia. The respondents comprised 15 males and 15 females with ages between 16 years and 18 years. Two instruments, namely, Scale of Attitude toward Computer Technologies (SACT) and Barriers affecting Students' Attitudes and Use (BSAU) were used to collect data. The Technology Acceptance Model (TAM) of Davis (1989) was utilized. The analysis of the study revealed gender differences in attitudes toward the use of computer technologies in learning English. Female students showed high and positive attitudes towards the use of computer technologies in learning English than males. Both male and female participants demonstrated high and positive perception of Usefulness and perceived Ease of Use of computer technologies in learning English. Three barriers that affected and limited the use of computer technologies in learning English were identified by the participants. These barriers are skill, equipment, and motivation. Among these barriers, skill had the highest effect, whereas motivation showed the least effect.

Along the speciation continuum: Quantifying intrinsic and extrinsic isolating barriers across five million years of evolutionary divergence in California jewelflowers.

PubMed

Christie, Kyle; Strauss, Sharon Y

2018-05-01

Understanding the relative roles of intrinsic and extrinsic reproductive barriers, and their interplay within the geographic context of diverging taxa, remains an outstanding challenge in the study of speciation. We conducted a comparative analysis of reproductive isolation in California Jewelflowers (Streptanthus, s.l., Brassicaceae) by quantifying potential barriers to gene flow at multiple life history stages in 39 species pairs spanning five million years of evolutionary divergence. We quantified nine potential pre- and postzygotic barriers and explored patterns of reproductive isolation in relation to genetic distance. Intrinsic postzygotic isolation was initially weak, increased at intermediate genetic distances, and reached a threshold characterized by complete genetic incompatibility. Climatic niche differences were strong at shallow genetic distances, and species pairs with overlapping ranges showed slight but appreciable phenological isolation, highlighting the potential for ecological barriers to contribute to speciation. Geographic analyses suggest that speciation is not regionally allopatric in the California Jewelflowers, as recently diverged taxa occur in relatively close proximity and display substantial range overlap. Young pairs are characterized by incomplete intrinsic postzygotic isolation, suggesting that extrinsic barriers or fine-scale spatial segregation are more important early in the divergence process than genetic incompatibilities. © 2018 The Author(s). Evolution © 2018 The Society for the Study of Evolution.

Factors predicting barriers to exercise in midlife Australian women.

PubMed

McGuire, Amanda; Seib, Charrlotte; Anderson, Debra

2016-05-01

Chronic diseases are the leading cause of death and disability worldwide. They are, though, largely attributable to modifiable lifestyle risk factors, including lack of exercise. This study aims to investigate what factors predict perceptions of barriers to exercise in midlife women. This cross-sectional descriptive study collected data from midlife Australian women by online questionnaire. Volunteers aged between 40 and 65 years were recruited following media publicity about the study. The primary outcome measure was perceived exercise barriers (EBBS Barriers sub-scale). Other self-report data included: exercise, smoking, alcohol, fruit and vegetable consumption, body mass index, physical and mental health and well-being (MOS SF-12v2) and exercise self-efficacy. On average, the 225 participants were aged 50.9 years (SD=5.9). The significant predictors of perceived barriers to exercise were perceived benefits of exercise, exercise self-efficacy, physical well-being and mental well-being. These variables explained 41% of the variance in the final model (F (8219)=20.1, p<.01) CONCLUSIONS: In midlife women, perceptions of barriers to exercise correlate with beliefs about the health benefits of exercise, exercise self-efficacy, physical and mental well-being. These findings have application to health promotion interventions targeting exercise behaviour change in midlife women. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Barriers, benefits and behaviors related to breakfast consumption among rural adolescents

PubMed Central

Shanafelt, Amy; Wang, Qi; Leduc, Robert; Nanney, Marilyn S.

2015-01-01

Background We sought to determine if perceived barriers, benefits, and modifiable behaviors support or interfere with breakfast consumption in a racially and economically diverse rural high school population. Methods The participants were 832 Minnesota adolescents from 16 rural high schools. We used baseline data from a group randomized trial aimed at increasing school breakfast participation through policy and environmental-level school changes. Students completed an online survey asking about demographics, breakfast eating behaviors, and the barriers and benefits of eating as it relates to school performance. Bivariate and multivariate logistic regression, accounting for clustering by school, was performed using SAS. Each scale was modeled independently. Results Participants were 9th and 10th grade students, 36% free/reduced price lunch (FRL), 30% non-white and 55% female. Breakfast skippers compared to non-breakfast skippers reported fewer school related benefits and beliefs and more barriers to eating breakfast (p < .01). Adjusted models revealed students reported more positive beliefs (OR= 0.78, 95%CI=0.73-0.83), more benefits (OR=0.95, 95% CI=0.93-0.97) and fewer barriers (OR=0.85, 95%CI=0.82-0.87) and were less likely to skip breakfast. Conclusions Future intervention research should focus on alleviating barriers and enhancing education around the school related benefits of eating breakfast. PMID:26830505

Drop-wise and film-wise water condensation processes occurring on metallic micro-scaled surfaces

NASA Astrophysics Data System (ADS)

Starostin, Anton; Valtsifer, Viktor; Barkay, Zahava; Legchenkova, Irina; Danchuk, Viktor; Bormashenko, Edward

2018-06-01

Water condensation was studied on silanized (superhydrophobic) and fluorinated (superoleophobic) micro-rough aluminum surfaces of the same topography. Condensation on superhydrophobic surfaces occurred via film-wise mechanism, whereas on superoleophobic surfaces it was drop-wise. The difference in the pathways of condensation was attributed to the various energy barriers separating the Cassie and Wenzel wetting states on the investigated surfaces. The higher barriers inherent for superoleophobic surfaces promoted the drop-wise condensation. Triple-stage kinetics of growth of droplets condensed on superoleophobic surfaces is reported and discussed.

Measuring immigration stress of first-generation female Korean immigrants in California: psychometric evaluation of Demand of Immigration Scale.

PubMed

Ding, Ding; Hofstetter, C Richard; Norman, Gregory J; Irvin, Veronica L; Chhay, Douglas; Hovell, Melbourne F

2011-02-01

Immigration involves challenges and distress, which affect health and well-being of immigrants. Koreans are a recent, fast-growing, but understudied group of immigrants in the USA, and no study has established or evaluated any immigration stress measure among this population. This study explores psychometric properties of Korean-translated Demands of Immigration (DI) Scale among first-generation female Korean immigrants in California. Analyses included evaluation of factor structure, reliability, validity, and descriptive statistics of subscales. A surname-driven sampling strategy was applied to randomly select a representative sample of adult female Korean immigrants in California. Telephone interviews were conducted by trained bilingual interviewers. Study sample included 555 first-generation female Korean immigrants who were interviewed in Korean language. The 22-item DI Scale was used to assess immigration stress in the study sample. Exploratory factor analysis suggested six correlated factors in the DI Scale: language barriers; sense of loss; not feeling at home; perceived discrimination; novelty; and occupation. Confirmatory factor analysis validated the factor structure. Language barriers accounted for the most variance of the DI Scale (29.11%). The DI Scale demonstrated good internal consistency reliability and construct validity. Evidence has been offered that the Korean-translated DI Scale is a reliable and valid measurement tool to examine immigration stress among Korean immigrants. The Korean-translated DI Scale has replicated factor structure obtained in other ethnicities, but addition of cultural-specific items is suggested for Korean immigrants. High levels of language and occupation-related stress warrant attention from researchers, social workers, and policy-makers. Findings from this study will inform future interventions to alleviate stress due to demands of immigration.

A Commercialization Roadmap for Carbon-Negative Energy Systems

NASA Astrophysics Data System (ADS)

Sanchez, D.

2016-12-01

The Intergovernmental Panel on Climate Change (IPCC) envisages the need for large-scale deployment of net-negative CO2 emissions technologies by mid-century to meet stringent climate mitigation goals and yield a net drawdown of atmospheric carbon. Yet there are few commercial deployments of BECCS outside of niche markets, creating uncertainty about commercialization pathways and sustainability impacts at scale. This uncertainty is exacerbated by the absence of a strong policy framework, such as high carbon prices and research coordination. Here, we propose a strategy for the potential commercial deployment of BECCS. This roadmap proceeds via three steps: 1) via capture and utilization of biogenic CO2 from existing bioenergy facilities, notably ethanol fermentation, 2) via thermochemical co-conversion of biomass and fossil fuels, particularly coal, and 3) via dedicated, large-scale BECCS. Although biochemical conversion is a proven first market for BECCS, this trajectory alone is unlikely to drive commercialization of BECCS at the gigatonne scale. In contrast to biochemical conversion, thermochemical conversion of coal and biomass enables large-scale production of fuels and electricity with a wide range of carbon intensities, process efficiencies and process scales. Aside from systems integration, primarily technical barriers are involved in large-scale biomass logistics, gasification and gas cleaning. Key uncertainties around large-scale BECCS deployment are not limited to commercialization pathways; rather, they include physical constraints on biomass cultivation or CO2 storage, as well as social barriers, including public acceptance of new technologies and conceptions of renewable and fossil energy, which co-conversion systems confound. Despite sustainability risks, this commercialization strategy presents a pathway where energy suppliers, manufacturers and governments could transition from laggards to leaders in climate change mitigation efforts.

Exploring seascape genetics and kinship in the reef sponge Stylissa carteri in the Red Sea

PubMed Central

Giles, Emily C; Saenz-Agudelo, Pablo; Hussey, Nigel E; Ravasi, Timothy; Berumen, Michael L

2015-01-01

A main goal of population geneticists is to study patterns of gene flow to gain a better understanding of the population structure in a given organism. To date most efforts have been focused on studying gene flow at either broad scales to identify barriers to gene flow and isolation by distance or at fine spatial scales in order to gain inferences regarding reproduction and local dispersal. Few studies have measured connectivity at multiple spatial scales and have utilized novel tools to test the influence of both environment and geography on shaping gene flow in an organism. Here a seascape genetics approach was used to gain insight regarding geographic and ecological barriers to gene flow of a common reef sponge, Stylissa carteri in the Red Sea. Furthermore, a small-scale (<1 km) analysis was also conducted to infer reproductive potential in this organism. At the broad scale, we found that sponge connectivity is not structured by geography alone, but rather, genetic isolation in the southern Red Sea correlates strongly with environmental heterogeneity. At the scale of a 50-m transect, spatial autocorrelation analyses and estimates of full-siblings revealed that there is no deviation from random mating. However, at slightly larger scales (100–200 m) encompassing multiple transects at a given site, a greater proportion of full-siblings was found within sites versus among sites in a given location suggesting that mating and/or dispersal are constrained to some extent at this spatial scale. This study adds to the growing body of literature suggesting that environmental and ecological variables play a major role in the genetic structure of marine invertebrate populations. PMID:26257865

Barriers of Developing Medical Tourism in a Destination: A Case of South Korea.

PubMed

Rokni, Ladan; Avci, Turgay; Park, Sam Hun

2017-07-01

This study aimed to determine the efficient factors that potentially lead to the barriers of developing medical tourism in South Korea. To explore the current medical tourism trend, a qualitative procedure was adopted. Besides analyzing the current situation of medical tourism in Korea through a systematic searching on the available information and publications, in-depth-interviews were conducted to collect data from relevant authorities and representatives of medical tourism associations in this country. The result revealed, although government have supported this industry, that lack of specialty and expertise among the health care practitioners in the scope of cross cultural communication, seems to be the core barrier to development of medical tourism in Korea. Demands for convenient promotional activities, policy making and action regulation are the other effective factors. Several strategies are required in order to address and combat these barriers, such as governmental support for cultural training, cooperative efforts to encourage health practitioners involved to enhance their cultural and linguistic competence in international scale.

Barriers of Developing Medical Tourism in a Destination: A Case of South Korea

PubMed Central

ROKNI, Ladan; AVCI, Turgay; PARK, Sam Hun

2017-01-01

Background: This study aimed to determine the efficient factors that potentially lead to the barriers of developing medical tourism in South Korea. Methods: To explore the current medical tourism trend, a qualitative procedure was adopted. Besides analyzing the current situation of medical tourism in Korea through a systematic searching on the available information and publications, in-depth-interviews were conducted to collect data from relevant authorities and representatives of medical tourism associations in this country. Results: The result revealed, although government have supported this industry, that lack of specialty and expertise among the health care practitioners in the scope of cross cultural communication, seems to be the core barrier to development of medical tourism in Korea. Demands for convenient promotional activities, policy making and action regulation are the other effective factors. Discussion: Several strategies are required in order to address and combat these barriers, such as governmental support for cultural training, cooperative efforts to encourage health practitioners involved to enhance their cultural and linguistic competence in international scale. PMID:28845404

Reconfigurable origami sonic barriers with tunable bandgaps for traffic noise mitigation

NASA Astrophysics Data System (ADS)

Thota, M.; Wang, K. W.

2017-10-01

An origami sonic barrier composed of cylindrical inclusions attached onto an origami sheet is proposed. The idea allows for tunable sound blocking properties for application in attenuating complex traffic noise spectra. Folding of the underlying origami sheet transforms the periodicity of the inclusions between different Bravais lattices, viz. between a square and a hexagonal lattice, and such significant lattice re-configuration leads to drastic tuning of dispersion characteristics. The wave tuning capabilities are corroborated via performing theoretical and numerical investigations using a plane wave expansion method and an acoustic simulation package of COMSOL, while experiments are performed on a one-seventh scaled-down model of origami sonic barrier to demonstrate the lattice re-configuration between different Bravais lattices and the associated bandgap adaptability. Good sound blocking performance in the frequency range of traffic noise spectra combined with less efforts, required for actuating one-degree of freedom folding mechanism, makes the origami sonic barrier a potential candidate for mitigating complex traffic noise.

Thermal stability and formation barrier of a high-energetic material N8 polymer nitrogen encapsulated in (5,5) carbon nanotube

NASA Astrophysics Data System (ADS)

Ji, Wei; Timoshevskii, V.; Guo, H.; Abou-Rachid, Hakima; Lussier, Louis-Simon

2009-07-01

We report the density functional theory total energy calculations of thermal stability and formation barrier of polymer nitrogen confined in carbon nanotubes (CNT). The analysis suggests that N8 polymer nitrogen encapsulated in (5,5) carbon nanotube [N8@CNT(5,5)] is thermally (meta)stable at a finite temperature up to energy scale of at least 5000 K, similar to nitrogen molecule gas phase confined in CNT [N2@CNT(5,5)]. The energetic difference between these two phases of N does not significantly change with temperature. A barrier of 1.07 eV was found for the formation of N8@CNT(5,5) from N2@CNT(5,5), while the dissociation barrier was found to be 0.2 eV. Snapshots of the reaction pathway show that the transition state is composed by a N2 and a N6 inside a CNT(5,5).

Delay time in a single barrier for a movable quantum shutter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hernandez, Alberto

2010-05-15

The transient solution and delay time for a {delta} potential scatterer with a movable quantum shutter is calculated by solving analytically the time-dependent Schroedinger equation. The delay time is analyzed as a function of the distance between the shutter and the potential barrier and also as a function of the distance between the potential barrier and the detector. In both cases, it is found that the delay time exhibits a dynamical behavior and that it tends to a saturation value {Delta}t{sub sat} in the limit of very short distances, which represents the maximum delay produced by the potential barrier nearmore » the interaction region. The phase time {tau}{sub {theta},} on the other hand, is not an appropriate time scale for measuring the time delay near the interaction region, except if the shutter is moved far away from the potential. The role played by the antibound state of the system on the behavior of the delay time is also discussed.« less

Spatial fluctuations in barrier height at the graphene-silicon carbide Schottky junction.

PubMed

Rajput, S; Chen, M X; Liu, Y; Li, Y Y; Weinert, M; Li, L

2013-01-01

When graphene is interfaced with a semiconductor, a Schottky contact forms with rectifying properties. Graphene, however, is also susceptible to the formation of ripples upon making contact with another material. Here we report intrinsic ripple- and electric field-induced effects at the graphene semiconductor Schottky junction, by comparing chemical vapour-deposited graphene transferred on semiconductor surfaces of opposite polarization-the hydrogen-terminated silicon and carbon faces of hexagonal silicon carbide. Using scanning tunnelling microscopy/spectroscopy and first-principles calculations, we show the formation of a narrow Schottky dipole barrier approximately 10 Å wide, which facilitates the observed effective electric field control of the Schottky barrier height. We further find atomic-scale spatial fluctuations in the Schottky barrier that directly follow the undulation of ripples on both graphene-silicon carbide junctions. These findings reveal fundamental properties of the graphene/semiconductor Schottky junction-a key component of vertical graphene devices that offer functionalities unattainable in planar device architecture.

Understanding trends in C-H bond activation in heterogeneous catalysis.

PubMed

Latimer, Allegra A; Kulkarni, Ambarish R; Aljama, Hassan; Montoya, Joseph H; Yoo, Jong Suk; Tsai, Charlie; Abild-Pedersen, Frank; Studt, Felix; Nørskov, Jens K

2017-02-01

While the search for catalysts capable of directly converting methane to higher value commodity chemicals and liquid fuels has been active for over a century, a viable industrial process for selective methane activation has yet to be developed. Electronic structure calculations are playing an increasingly relevant role in this search, but large-scale materials screening efforts are hindered by computationally expensive transition state barrier calculations. The purpose of the present letter is twofold. First, we show that, for the wide range of catalysts that proceed via a radical intermediate, a unifying framework for predicting C-H activation barriers using a single universal descriptor can be established. Second, we combine this scaling approach with a thermodynamic analysis of active site formation to provide a map of methane activation rates. Our model successfully rationalizes the available empirical data and lays the foundation for future catalyst design strategies that transcend different catalyst classes.

Understanding trends in C–H bond activation in heterogeneous catalysis

DOE PAGES

Latimer, Allegra A.; Kulkarni, Ambarish R.; Aljama, Hassan; ...

2016-10-10

While the search for catalysts capable of directly converting methane to higher value commodity chemicals and liquid fuels has been active for over a century, a viable industrial process for selective methane activation has yet to be developed1. Electronic structure calculations are playing an increasingly relevant role in this search, but large-scale materials screening efforts are hindered by computationally expensive transition state barrier calculations. The purpose of the present letter is twofold. First, we show that, for the wide range of catalysts that proceed via a radical intermediate, a unifying framework for predicting C–H activation barriers using a single universalmore » descriptor can be established. Second, we combine this scaling approach with a thermodynamic analysis of active site formation to provide a map of methane activation rates. Lastly, our model successfully rationalizes the available empirical data and lays the foundation for future catalyst design strategies that transcend different catalyst classes.« less

Biological Conversion of Sugars to Hydrocarbons Technology Pathway

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davis, Ryan; Biddy, Mary J.; Tan, Eric

2013-03-31

In support of the Bioenergy Technologies Office, the National Renewable Energy Laboratory (NREL) and the Pacific Northwest National Laboratory (PNNL) are undertaking studies of biomass conversion technologies to identify barriers and target research toward reducing conversion costs. Process designs and preliminary economic estimates for each of these pathway cases were developed using rigorous modeling tools (Aspen Plus and Chemcad). These analyses incorporated the best information available at the time of development, including data from recent pilot and bench-scale demonstrations, collaborative industrial and academic partners, and published literature and patents. This technology pathway case investigates the biological conversion of biomass derivedmore » sugars to hydrocarbon biofuels, utilizing data from recent literature references and information consistent with recent pilot scale demonstrations at NREL. Technical barriers and key research needs have been identified that should be pursued for the pathway to become competitive with petroleum-derived gasoline, diesel and jet range hydrocarbon blendstocks.« less

Understanding trends in C-H bond activation in heterogeneous catalysis

NASA Astrophysics Data System (ADS)

Latimer, Allegra A.; Kulkarni, Ambarish R.; Aljama, Hassan; Montoya, Joseph H.; Yoo, Jong Suk; Tsai, Charlie; Abild-Pedersen, Frank; Studt, Felix; Nørskov, Jens K.

2017-02-01

While the search for catalysts capable of directly converting methane to higher value commodity chemicals and liquid fuels has been active for over a century, a viable industrial process for selective methane activation has yet to be developed. Electronic structure calculations are playing an increasingly relevant role in this search, but large-scale materials screening efforts are hindered by computationally expensive transition state barrier calculations. The purpose of the present letter is twofold. First, we show that, for the wide range of catalysts that proceed via a radical intermediate, a unifying framework for predicting C-H activation barriers using a single universal descriptor can be established. Second, we combine this scaling approach with a thermodynamic analysis of active site formation to provide a map of methane activation rates. Our model successfully rationalizes the available empirical data and lays the foundation for future catalyst design strategies that transcend different catalyst classes.

Large-Scale First-Principles Molecular Dynamics Simulations with Electrostatic Embedding: Application to Acetylcholinesterase Catalysis

DOE PAGES

Fattebert, Jean-Luc; Lau, Edmond Y.; Bennion, Brian J.; ...

2015-10-22

Enzymes are complicated solvated systems that typically require many atoms to simulate their function with any degree of accuracy. We have recently developed numerical techniques for large scale First-Principles molecular dynamics simulations and applied them to study the enzymatic reaction catalyzed by acetylcholinesterase. We carried out Density functional theory calculations for a quantum mechanical (QM) sub- system consisting of 612 atoms with an O(N) complexity finite-difference approach. The QM sub-system is embedded inside an external potential field representing the electrostatic effect due to the environment. We obtained finite temperature sampling by First-Principles molecular dynamics for the acylation reaction of acetylcholinemore » catalyzed by acetylcholinesterase. Our calculations shows two energies barriers along the reaction coordinate for the enzyme catalyzed acylation of acetylcholine. In conclusion, the second barrier (8.5 kcal/mole) is rate-limiting for the acylation reaction and in good agreement with experiment.« less

Can a science-based definition of acupuncture improve clinical outcomes?

PubMed

Priebe, Ted; Stumpf, Steven H; Zalunardo, Rod

2017-05-01

Research on acupuncture has been muddled by attempts to bridge the ancient with the modern. Barriers to effectiveness research are reflected in recurring conflicts that include disagreement on use of the most basic terms, lack of standard intervention controls, and the absence of functional measures for assessing treatment effect. Acupuncture research has stalled at the "placebo barrier" wherein acupuncture is "no better than placebo." The most widely recognized comparative effectiveness research in acupuncture does not compare acupuncture treatment protocols within groups, thereby, mutating large scale effectiveness studies into large scale efficacy trials. Too often research in acupuncture attempts to tie outcomes to traditional belief systems thereby limiting usefulness of the research. The acupuncture research paradigm needs to focus more closely on a scientific definition of treatments and outcomes that compare protocols in terms of prevalent clinical issues such as relative effectiveness for treating pain.

Resolving the mystery of transport within internal transport barriers

DOE PAGES

Staebler, Gary M.; Kinsey, Jon E.; Belli, Emily A.; ...

2014-05-02

Here, the Trapped Gyro-Landau Fluid (TGLF) quasi-linear model, which is calibrated to nonlinear gyrokinetic turbulence simulations, is now able to predict the electron density, electron and ion temperatures and ion toroidal rotation simultaneously for internal transport barrier (ITB) discharges. This is a strong validation of gyrokinetic theory of ITBs, requiring multiple instabilities responsible for transport in different channels at different scales. The mystery of transport inside the ITB is that momentum and particle transport is far above the predicted neoclassical levels in apparent contradiction with the expectation from the theory of suppression of turbulence by E × B velocity shear.more » The success of TGLF in predicting ITB transport is due to the inclusion of ion gyro-radius scale modes that become dominant at high E × B velocity shear and to improvements to TGLF that allow momentum transport from gyrokinetic turbulence to be faithfully modeled.« less

How should support for climate-friendly technologies be designed?

PubMed

Fischer, Carolyn; Torvanger, Asbjørn; Shrivastava, Manish Kumar; Sterner, Thomas; Stigson, Peter

2012-01-01

Stabilizing global greenhouse gas concentrations at levels to avoid significant climate risks will require massive "decarbonization" of all the major economies over the next few decades, in addition to the reduced emissions from other GHGs and carbon sequestration. Achieving the necessary scale of emissions reductions will require a multifaceted policy effort to support a broad array of technological and behavioral changes. Change on this scale will require sound, well-thought-out strategies. In this article, we outline some core principles, drawn from recent social science research, for guiding the design of clean technology policies, with a focus on energy. The market should be encouraged to make good choices: pricing carbon emissions and other environmental damage, removing distorting subsidies and barriers to competition, and supporting RD&D broadly. More specific policies are required to address particular market failures and barriers. For those technologies identified as being particularly desirable, some narrower RD&D policies are available.

Landslide barriers at A83 Rest and be Thankful in Scotland and their first event 2015

NASA Astrophysics Data System (ADS)

Wendeler, Corinna; Volkwein, Axel; Luis, Roberto

2016-04-01

Rest and be Thankful is a part of the road A83 in northern Scotland and has a long history of landslides. In 2007, the site was closed for several weeks after a shallow landslide. A kind of mudslides deposited 400 tons of material on the road. In early September 2009, a further event resulted in 1070 tons of material slipping onto the road at the same place, forcing its closure for 48 hours. No one was hurt in either incident, but these slides pose a serious threat to the country's main rural routes (Gibson, 2010). The site has then been the subject of study and is included in the recent Scottish Roads Network Landslides Study produced by Transport Scotland. The study identified the A83 at Rest and be Thankful as one of the most risk sites for debris flow and/or landslides - a fact confirmed by the events that have occurred. The development of flexible debris flow and landslide barriers is more recent but has reached a point where they may be designed, specified and installed with confidence. Indeed, installations are now quite common in European alpine areas, California, Japan and Korea in particular. The standard system SL-150 of company Geobrugg with a height of 3.5 m was installed in 2011, the design parameters as well as the calculation of the structural system were checked by WSL to fulfil newest research results out of a 3 year research project (Bugnion et al, 2011 and 2012). In 2015, the first event happened to the barrier SL-150. Storm Desmond released on Saturday 5th December during daytime a first slide of around 150 m3 into the barrier, afterwards around night time a second slide with 100 m3 impacted the same barrier and some smaller slides followed. In total 300 m3 of material were captured successfully by that SL-150 barrier and the major transport route in this area remained open while storm Desmond. No failure at the barrier happened, only the so called energy absorbers got activated. A big success of the past research project in which originally the loading approach and the system itself were developed. The maintenance work at the barrier itself will now be to clean up, and to re-install the energy absorbers. Then the barrier is ready again for new events. References Winter M G, Macgregor F, Shack-man L (2008) Scottish Road Network Landslides Study Edinburgh. Gibson D (2010) Landslide Victory, the UK's first flexible debris flow barrier being installed at the landslide prone Rest and be Thankful site in Scotland, Ground Engineering April 2010. Bugnion L, McArdell B, Bartelt P, Wendeler C (2011) Measurements of Hillslope Debris Flow Impact Pressure on Obstacles. Landslides, 9, 179-187. Bugnion L, Wendeler C (2010) Shallow landslide full-scale experiments in combination with testing of flexible barrier. Debris Flow 2010 Milano, Italy. Bugnion L, Boetticher A v, Wendeler C (2012) Large scale field Testing of hill slope debris flows resulting in The Design of Flexible Protection Barriers, Abstract of 12th Interprevent Conference 2012 Grenoble, France.

Evaluating the long-term hydrology of an evapotranspiration-capillary barrier with a 1000 year design life: HYDROLOGY OF A 1000 YEAR ETC BARRIER

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Z. Fred

A surface barrier (or cover) is a commonly used technology for subsurface remediation. A key function of the barrier is to reduce or eliminate the movement of meteoric precipitation into the underlying waste zone, where it could mobilize and transport contaminants. Surface barriers are expected to perform for centuries to millennia, yet there are very few examples of performance for periods longer than a decade. The Prototype Hanford Barrier was constructed in 1994 over an existing waste site to demonstrate its long-term performance for a design period of 1000 years. This barrier is a field-scale evapotranspiration-capillary (ETC) barrier. In thismore » design, the storage layer consists of 2-m-thick silt loam. The 19-year monitoring results show that the store-and-release mechanism for the ETC barrier worked efficiently as the storage layer was recharged in the winter season (November to March) and the stored water was released to the atmosphere in the summer season (April to October) via soil evaporation and plant transpiration. The capillary break functioned normally in improving the storage capacity and minimizing drainage. The maximum drainage observed through the ET barrier at any of the monitoring stations was only 0.178 mm yr-1 (under an enhanced precipitation condition), which is less than the design criterion. A very small amount (2.0 mm yr-1 on average) of runoff was observed during the 19-year monitoring period. The observed storage capacity of the storage layer was considerably (39%) larger than the estimated value based on the method of equilibrium of water pressure. After a controlled fire in 2008, the newly grown vegetation (primarily shallow-rooted grasses) could still release the stored water and summer precipitation to the atmosphere via transpiration. The findings are useful for predicting water storage and ET under different precipitation conditions and for the design of future barriers.« less

Learning from social media: utilizing advanced data extraction techniques to understand barriers to breast cancer treatment.

PubMed

Freedman, Rachel A; Viswanath, Kasisomayajula; Vaz-Luis, Ines; Keating, Nancy L

2016-07-01

Past examinations of breast cancer treatment barriers have typically included registry, claims-based, and smaller survey studies. We examined treatment barriers using a novel, comprehensive, social media analysis of online, candid discussions about breast cancer. Using an innovative toolset to search postings on social networks, message boards, patient communities, and topical sites, we performed a large-scale qualitative analysis. We examined the sentiments and barriers expressed about breast cancer treatments by Internet users during 1 year (2/1/14-1/31/15). We categorized posts based on thematic patterns and examined trends in discussions by race/ethnicity (white/black/Hispanic) when this information was available. We identified 1,024,041 unique posts related to breast cancer treatment. Overall, 57 % of posts expressed negative sentiments. Using machine learning software, we assigned treatment barriers for 387,238 posts (38 %). Barriers included emotional (23 % of posts), preferences and spiritual/religious beliefs (21 %), physical (18 %), resource (15 %), healthcare perceptions (9 %), treatment processes/duration (7 %), and relationships (7 %). Black and Hispanic (vs. white) users more frequently reported barriers related to healthcare perceptions, beliefs, and pre-diagnosis/diagnosis organizational challenges and fewer emotional barriers. Using a novel analysis of diverse social media users, we observed numerous breast cancer treatment barriers that differed by race/ethnicity. Social media is a powerful tool, allowing use of real-world data for qualitative research, capitalizing on the rich discussions occurring spontaneously online. Future research should focus on how to further employ and learn from this type of social intelligence research across all medical disciplines.

Breaking barriers through collaboration: the example of the Cell Migration Consortium.

PubMed

Horwitz, Alan Rick; Watson, Nikki; Parsons, J Thomas

2002-10-15

Understanding complex integrated biological processes, such as cell migration, requires interdisciplinary approaches. The Cell Migration Consortium, funded by a Large-Scale Collaborative Project Award from the National Institute of General Medical Science, develops and disseminates new technologies, data, reagents, and shared information to a wide audience. The development and operation of this Consortium may provide useful insights for those who plan similarly large-scale, interdisciplinary approaches.

An Assessment of Mentoring Functions and Barriers to Mentoring

DTIC Science & Technology

1999-12-01

were similarity between mentor and mentee and the quality of the supervisory relationship in terms of LMX and psychosocial and career development ... psychosocial (1985). These broad categories have remained at the core of mentoring from the time they were developed . Career development functions "help...internal consistency reported by Noe for the career development functions scale (7 items) was .89. The psychosocial functions scale, made up of 14 items

Properties of gelatin film from horse mackerel (Trachurus japonicus) scale.

PubMed

Le, Thuy; Maki, Hiroki; Takahashi, Kigen; Okazaki, Emiko; Osako, Kazufumi

2015-04-01

Optimal conditions for extracting gelatin and preparing gelatin film from horse mackerel scale, such as extraction temperature and time, as well as the protein concentration of film-forming solutions were investigated. Yields of extracted gelatin at 70 °C, 80 °C, and 90 °C for 15 min to 3 h were 1.08% to 3.45%, depending on the extraction conditions. Among the various extraction times and temperatures, the film from gelatin extracted at 70 °C for 1 h showed the highest tensile strength and elongation at break. Horse mackerel scale gelatin film showed the greatly low water vapor permeability (WVP) compared with mammalian or fish gelatin films, maybe due to its containing a slightly higher level of hydrophobic amino acids (total 653 residues per 1000 residues) than that of mammalian, cold-water fish and warm-water fish gelatins. Gelatin films from different preparation conditions showed excellent UV barrier properties at wavelength of 200 nm, although the films were transparent at visible wavelength. As a consequence, it can be suggested that gelatin film from horse mackerel scale extracted at 70 °C for 1 h can be applied to food packaging material due to its lowest WVP value and excellent UV barrier properties. © 2015 Institute of Food Technologists®

A planktonic diatom displays genetic structure over small spatial scales.

PubMed

Sefbom, Josefin; Kremp, Anke; Rengefors, Karin; Jonsson, Per R; Sjöqvist, Conny; Godhe, Anna

2018-04-03

Marine planktonic microalgae have potentially global dispersal, yet reduced gene flow has been confirmed repeatedly for several species. Over larger distances (>200 km) geographic isolation and restricted oceanographic connectivity have been recognized as instrumental in driving population divergence. Here we investigated whether similar patterns, that is, structured populations governed by geographic isolation and/or oceanographic connectivity, can be observed at smaller (6-152 km) geographic scales. To test this we established 425 clonal cultures of the planktonic diatom Skeletonema marinoi collected from 11 locations in the Archipelago Sea (northern Baltic Sea). The region is characterized by a complex topography, entailing several mixing regions of which four were included in the sampling area. Using eight microsatellite markers and conventional F-statistics, significant genetic differentiation was observed between several sites. Moreover, Bayesian cluster analysis revealed the co-occurrence of two genetic groups spread throughout the area. However, geographic isolation and oceanographic connectivity could not explain the genetic patterns observed. Our data reveal hierarchical genetic structuring whereby despite high dispersal potential, significantly diverged populations have developed over small spatial scales. Our results suggest that biological characteristics and historical events may be more important in generating barriers to gene flow than physical barriers at small spatial scales. © 2018 Society for Applied Microbiology and John Wiley & Sons Ltd.

Artificial barriers prevent genetic recovery of small isolated populations of a low-mobility freshwater fish.

PubMed

Coleman, R A; Gauffre, B; Pavlova, A; Beheregaray, L B; Kearns, J; Lyon, J; Sasaki, M; Leblois, R; Sgro, C; Sunnucks, P

2018-06-01

Habitat loss and fragmentation often result in small, isolated populations vulnerable to environmental disturbance and loss of genetic diversity. Low genetic diversity can increase extinction risk of small populations by elevating inbreeding and inbreeding depression, and reducing adaptive potential. Due to their linear nature and extensive use by humans, freshwater ecosystems are especially vulnerable to habitat loss and fragmentation. Although the effects of fragmentation on genetic structure have been extensively studied in migratory fishes, they are less understood in low-mobility species. We estimated impacts of instream barriers on genetic structure and diversity of the low-mobility river blackfish (Gadopsis marmoratus) within five streams separated by weirs or dams constructed 45-120 years ago. We found evidence of small-scale (<13 km) genetic structure within reaches unimpeded by barriers, as expected for a fish with low mobility. Genetic diversity was lower above barriers in small streams only, regardless of barrier age. In particular, one isolated population showed evidence of a recent bottleneck and inbreeding. Differentiation above and below the barrier (F ST  = 0.13) was greatest in this stream, but in other streams did not differ from background levels. Spatially explicit simulations suggest that short-term barrier effects would not be detected with our data set unless effective population sizes were very small (<100). Our study highlights that, in structured populations, the ability to detect short-term genetic effects from barriers is reduced and requires more genetic markers compared to panmictic populations. We also demonstrate the importance of accounting for natural population genetic structure in fragmentation studies.

Placing barrier-island transgression in a blue-carbon context

NASA Astrophysics Data System (ADS)

Theuerkauf, Ethan J.; Rodriguez, Antonio B.

2017-07-01

Backbarrier saltmarshes are considered carbon sinks; however, barrier island transgression and the associated processes of erosion and overwash are typically not included in coastal carbon budgets. Here, we present a carbon-budget model for transgressive barrier islands that includes a dynamic carbon-storage term, driven by backbarrier-marsh width, and a carbon-export term, driven by ocean and backbarrier shoreline erosion. To examine the impacts of storms, human disturbances and the backbarrier setting of a transgressive barrier island on carbon budgets and reservoirs, the model was applied to sites at Core Banks and Onslow Beach, NC, USA. Results show that shoreline erosion and burial of backbarrier marsh from washover deposition and dredge-spoil disposal temporarily transitioned each site into a net exporter (source) of carbon. The magnitude of the carbon reservoir was linked to the backbarrier setting of an island. Carbon reservoirs of study sites separated from the mainland by only backbarrier marsh (no lagoon) decreased for over a decade because carbon storage could not keep pace with erosion. With progressive narrowing of the backbarrier marsh, these barriers will begin to function more persistently as carbon sources until the reservoir is depleted at the point where the barrier welds with the mainland. Undeveloped barrier islands with wide lagoons are carbon sources briefly during erosive periods; however, at century time scales are net carbon importers (sinks) because new marsh habitat can form during barrier rollover. Human development on backbarrier saltmarsh serves to reduce the carbon storage capacity and can hasten the transition of an island from a sink to a source.

Barriers to meditation by gender and age among cancer family caregivers.

PubMed

Williams, Anna-Leila; Ness, Peter Van; Dixon, Jane; McCorkle, Ruth

2012-01-01

Despite solid basic science research supporting meditation's physiologic benefits, meditation remains a marginalized practice for many Westerners; observational and descriptive studies indicate a spectrum of barriers to meditation practice. The aim of this study was to determine differences in barriers to meditation by gender and age. A cross-sectional survey study of 150 family caregivers to adults with cancer visiting an outpatient chemotherapy center in Connecticut was conducted. The primary outcome was the Determinants of Meditation Practice Inventory. Explanatory variables included demographic characteristics, Center for Epidemiologic Studies-Depression Scale, Big Five Inventory, and Caregiver Reaction Assessment. Participants included 98 women and 52 men. Age range was 18-84 years (M = 52.3 years). The highest frequency of barriers for both genders related to misconceptions about meditation. The total number of barriers to meditation did not significantly vary by gender (p = .10) nor age (p = .27). After adjusting for personality trait, reactions to caregiving, and emotional distress, gender (adjusted β = 0.81, SE = 1.70, p = .63) and age (adjusted β = 0.02, SE = 0.05, p = .67) still did not predict the number of barriers to meditation. Backward elimination in model building showed that personality trait and reactions to caregiving account for 32% of the variability in barriers. The total number of barriers to meditation was examined, and a difference was not found by age or gender. It is possible that differences by age and gender exist at the item level of evaluation but were not evident when evaluating total scores. Further study is needed with samples large enough to have statistical power for item-level analysis.

Perceived benefits and barriers to exercise among persons with physical disabilities or chronic health conditions within action or maintenance stages of exercise.

PubMed

Malone, Laurie A; Barfield, J P; Brasher, Joel D

2012-10-01

Information regarding factors that affect the initial step to exercise behavior change among persons with physical disabilities or chronic health conditions is available in the literature but much less is known regarding perceived benefits and barriers to exercise among those who are regularly active. The purpose of this study was to examine the perceived benefits and barriers to exercise among persons with physical disabilities or chronic health conditions within action or maintenance stages of exercise. Participants (n = 152) completed the Exercise Benefits and Barriers Scale (EBBS). For data analyses, disabilities and health conditions were grouped as neuromuscular, orthopedic, cardiovascular/pulmonary, or multiple conditions. Multivariate analysis of variance (MANOVA) was conducted to determine if mean differences on EBBS benefits and barriers scores existed among disability types, between sexes, among age groups, and between physical activity levels. Sum scores were computed to determine the strongest benefit and barrier responses. No significant mean differences in EBBS scores were found between disability types, sexes, age groups, or physical activity levels (p > 0.05). Strongest benefit responses varied by group. Strongest barrier responses were the same for all demographic groups: "Exercise tires me," "Exercise is hard work for me," and "I am fatigued by exercise." EBBS scores were similar across disability/health condition, sex, age, and physical activity level. Primary benefits reported were in the areas of improved physical performance and psychological outlook whereas the primary barriers were in the area of physical exertion. Copyright © 2012 Elsevier Inc. All rights reserved.

Attitudinal barriers to help-seeking and preferences for mental health support among Australian fathers.

PubMed

Giallo, Rebecca; Dunning, Melissa; Gent, Angela

2017-07-01

To (a) identify attitudinal barriers to help-seeking for mental health difficulties among fathers of young children; (b) explore the relationships between perceived barriers to help-seeking and mental health difficulties (i.e. depressive, anxiety, stress symptoms); (c) identify socio-demographic factors associated with barriers to help-seeking; and (d) identify fathers' preferences for mental health support. One in 10 Australian fathers experience mental health difficulties in the early parenting period. Low rates of help-seeking and under-utilisation of health care services are key issues for the provision of mental health support to fathers at this important life stage. The sample consisted of 154 fathers of young children (aged 0-8 years) participating in an Australian online survey on parent wellbeing and parenting. The Barriers to Help-Seeking Scale assessed fathers' attitudinal barriers to help-seeking for mental health support. Socio-demographic factors related to fathers' employment, education, and family composition were assessed. The most common attitudinal barriers to help-seeking were: (a) the need for control and self-reliance in managing one's own problems, (b) a tendency to downplay or minimise problems, and (c) a sense of resignation that nothing will help. A range of demographic (i.e. age, educational attainment) factors were associated with these barriers. The most common preferences for support were internet-based information resources, followed by support provided by general practitioners and maternal child health nurses. These findings have important implications for health promotion, health services and clinical approaches to promoting the health and wellbeing of fathers.

H2@Scale Workshop Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pivovar, Bryan

2017-03-31

Final report from the H2@Scale Workshop held November 16-17, 2016, at the National Renewable Energy Laboratory in Golden, Colorado. The U.S. Department of Energy's National Renewable Energy Laboratory hosted a technology workshop to identify the current barriers and research needs of the H2@Scale concept. H2@Scale is a concept regarding the potential for wide-scale impact of hydrogen produced from diverse domestic resources to enhance U.S. energy security and enable growth of innovative technologies and domestic industries. Feedback received from a diverse set of stakeholders at the workshop will guide the development of an H2@Scale roadmap for research, development, and early stagemore » demonstration activities that can enable hydrogen as an energy carrier at a national scale.« less

Adsorption and diffusion of Ru adatoms on Ru(0001)-supported graphene: Large-scale first-principles calculations

DOE PAGES

Han, Yong; Evans, James W.

2015-10-27

Large-scale first-principles density functional theory calculations are performed to investigate the adsorption and diffusion of Ru adatoms on monolayer graphene (G) supported on Ru(0001). The G sheet exhibits a periodic moiré-cell superstructure due to lattice mismatch. Within a moiré cell, there are three distinct regions: fcc, hcp, and mound, in which the C6-ring center is above a fcc site, a hcp site, and a surface Ru atom of Ru(0001), respectively. The adsorption energy of a Ru adatom is evaluated at specific sites in these distinct regions. We find the strongest binding at an adsorption site above a C atom inmore » the fcc region, next strongest in the hcp region, then the fcc-hcp boundary (ridge) between these regions, and the weakest binding in the mound region. Behavior is similar to that observed from small-unit-cell calculations of Habenicht et al. [Top. Catal. 57, 69 (2014)], which differ from previous large-scale calculations. We determine the minimum-energy path for local diffusion near the center of the fcc region and obtain a local diffusion barrier of ~0.48 eV. We also estimate a significantly lower local diffusion barrier in the ridge region. These barriers and information on the adsorption energy variation facilitate development of a realistic model for the global potential energy surface for Ru adatoms. Furthermore, this in turn enables simulation studies elucidating diffusion-mediated directed-assembly of Ru nanoclusters during deposition of Ru on G/Ru(0001).« less

Groundwater declines are linked to changes in Great Plains stream fish assemblages

USGS Publications Warehouse

Prekins, Joshuah S.; Gido, Keith B.; Falke, Jeffrey A.; Fausch, Kurt D.; Crockett, Harry; Johnson, Eric R.; Sanderson, John

2017-01-01

Groundwater pumping for agriculture is a major driver causing declines of global freshwater ecosystems, yet the ecological consequences for stream fish assemblages are rarely quantified. We combined retrospective (1950–2010) and prospective (2011–2060) modeling approaches within a multiscale framework to predict change in Great Plains stream fish assemblages associated with groundwater pumping from the United States High Plains Aquifer. We modeled the relationship between the length of stream receiving water from the High Plains Aquifer and the occurrence of fishes characteristic of small and large streams in the western Great Plains at a regional scale and for six subwatersheds nested within the region. Water development at the regional scale was associated with construction of 154 barriers that fragment stream habitats, increased depth to groundwater and loss of 558 km of stream, and transformation of fish assemblage structure from dominance by large-stream to small-stream fishes. Scaling down to subwatersheds revealed consistent transformations in fish assemblage structure among western subwatersheds with increasing depths to groundwater. Although transformations occurred in the absence of barriers, barriers along mainstem rivers isolate depauperate western fish assemblages from relatively intact eastern fish assemblages. Projections to 2060 indicate loss of an additional 286 km of stream across the region, as well as continued replacement of large-stream fishes by small-stream fishes where groundwater pumping has increased depth to groundwater. Our work illustrates the shrinking of streams and homogenization of Great Plains stream fish assemblages related to groundwater pumping, and we predict similar transformations worldwide where local and regional aquifer depletions occur.

Localized extinction of an arboreal desert lizard caused by habitat fragmentation

USGS Publications Warehouse

Munguia-Vega, Adrian; Rodriguez-Estrella, Ricardo; Shaw, William W.; Culver, Melanie

2013-01-01

We adopted a species’ perspective for predicting extinction risk in a small, endemic, and strictly scansorial lizard (Urosaurus nigricaudus), in an old (∼60 year) and highly fragmented (8% habitat remaining) agricultural landscape from the Sonoran Desert, Mexico. We genotyped 10 microsatellite loci in 280 individuals from 11 populations in fragmented and continuous habitat. Individual dispersal was restricted to less than 400 m, according to analyses of spatial autocorrelation and spatially explicit Bayesian assignment methods. Within this scale, continuous areas and narrow washes with native vegetation allowed high levels of gene flow over tens of kilometers. In the absence of the native vegetation, cleared areas and highways were identified as partial barriers. In contrast, outside the scale of dispersal, cleared areas behaved as complete barriers, and surveys corroborated the species went extinct after a few decades in all small (less than 45 ha), isolated habitat fragments. No evidence for significant loss of genetic diversity was found, but results suggested fragmentation increased the spatial scale of movements, relatedness, genetic structure, and potentially affected sex-biased dispersal. A plausible threshold of individual dispersal predicted only 23% of all fragments in the landscape were linked with migration from continuous habitat, while complete barriers isolated the majority of fragments. Our study suggested limited dispersal, coupled with an inability to use a homogeneous and hostile matrix without vegetation and shade, could result in frequent time-delayed extinctions of small ectotherms in highly fragmented desert landscapes, particularly considering an increase in the risk of overheating and a decrease in dispersal potential induced by global warming.

High Disparity Between Orthopedic Resident Interest and Participation in International Health Electives.

PubMed

Zhang, Steven; Shultz, Paul; Daniels, Alan; Ackelman, Edward; Kamal, Robin N

2016-07-01

Few orthopedic surgical residency programs offer international health electives (IHEs). Efforts to expand these programs have been increasing across medical disciplines. Whether orthopedic residents will participate remains unknown. This study quantified and characterized orthopedic resident interest and barriers to IHEs in US residency programs. A web-based survey was administered to residents from 154 US orthopedic residency programs accredited by the Accreditation Council for Graduate Medical Education 2014 to 2015. Questions assessed demographics and program background, previous medical experience abroad, barriers to participation, and level of interest in participating in an international health elective during their training and beyond. Twenty-seven (17.5%) residency programs responded. Chi-square analysis showed that residents who expressed interest in participating were significantly more likely to have experience abroad compared with those who expressed no interest (P<.004). Analysis using Mann-Whitney U test suggested that those who expressed interest were more likely to believe IHEs are important to resident training (P<.0011; mean Likert scale score of 3.7 vs 2.6), provide valuable experience (P<.001; mean Likert scale score of 4.2 vs 3.2), and should be required for orthopedic residencies (P<.001; mean Likert scale score of 2.8 vs 1.9). Residents are strongly interested in participating in IHEs during their training, and many may integrate global health into future practices. Residents perceive lack of funding and scheduling flexibility as barriers preventing them from participating. Prior experience abroad influences level of interest, and international clinical experience may enhance future perception of its value. [Orthopedics. 2016; 39(4):e680-e686.]. Copyright 2016, SLACK Incorporated.

Groundwater declines are linked to changes in Great Plains stream fish assemblages.

PubMed

Perkin, Joshuah S; Gido, Keith B; Falke, Jeffrey A; Fausch, Kurt D; Crockett, Harry; Johnson, Eric R; Sanderson, John

2017-07-11

Groundwater pumping for agriculture is a major driver causing declines of global freshwater ecosystems, yet the ecological consequences for stream fish assemblages are rarely quantified. We combined retrospective (1950-2010) and prospective (2011-2060) modeling approaches within a multiscale framework to predict change in Great Plains stream fish assemblages associated with groundwater pumping from the United States High Plains Aquifer. We modeled the relationship between the length of stream receiving water from the High Plains Aquifer and the occurrence of fishes characteristic of small and large streams in the western Great Plains at a regional scale and for six subwatersheds nested within the region. Water development at the regional scale was associated with construction of 154 barriers that fragment stream habitats, increased depth to groundwater and loss of 558 km of stream, and transformation of fish assemblage structure from dominance by large-stream to small-stream fishes. Scaling down to subwatersheds revealed consistent transformations in fish assemblage structure among western subwatersheds with increasing depths to groundwater. Although transformations occurred in the absence of barriers, barriers along mainstem rivers isolate depauperate western fish assemblages from relatively intact eastern fish assemblages. Projections to 2060 indicate loss of an additional 286 km of stream across the region, as well as continued replacement of large-stream fishes by small-stream fishes where groundwater pumping has increased depth to groundwater. Our work illustrates the shrinking of streams and homogenization of Great Plains stream fish assemblages related to groundwater pumping, and we predict similar transformations worldwide where local and regional aquifer depletions occur.

Groundwater declines are linked to changes in Great Plains stream fish assemblages

PubMed Central

Perkin, Joshuah S.; Gido, Keith B.; Falke, Jeffrey A.; Fausch, Kurt D.; Crockett, Harry; Johnson, Eric R.; Sanderson, John

2017-01-01

Groundwater pumping for agriculture is a major driver causing declines of global freshwater ecosystems, yet the ecological consequences for stream fish assemblages are rarely quantified. We combined retrospective (1950–2010) and prospective (2011–2060) modeling approaches within a multiscale framework to predict change in Great Plains stream fish assemblages associated with groundwater pumping from the United States High Plains Aquifer. We modeled the relationship between the length of stream receiving water from the High Plains Aquifer and the occurrence of fishes characteristic of small and large streams in the western Great Plains at a regional scale and for six subwatersheds nested within the region. Water development at the regional scale was associated with construction of 154 barriers that fragment stream habitats, increased depth to groundwater and loss of 558 km of stream, and transformation of fish assemblage structure from dominance by large-stream to small-stream fishes. Scaling down to subwatersheds revealed consistent transformations in fish assemblage structure among western subwatersheds with increasing depths to groundwater. Although transformations occurred in the absence of barriers, barriers along mainstem rivers isolate depauperate western fish assemblages from relatively intact eastern fish assemblages. Projections to 2060 indicate loss of an additional 286 km of stream across the region, as well as continued replacement of large-stream fishes by small-stream fishes where groundwater pumping has increased depth to groundwater. Our work illustrates the shrinking of streams and homogenization of Great Plains stream fish assemblages related to groundwater pumping, and we predict similar transformations worldwide where local and regional aquifer depletions occur. PMID:28652354

Adsorption and diffusion of Ru adatoms on Ru(0001)-supported graphene: Large-scale first-principles calculations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Han, Yong; Evans, James W.

2015-10-28

Large-scale first-principles density functional theory calculations are performed to investigate the adsorption and diffusion of Ru adatoms on monolayer graphene (G) supported on Ru(0001). The G sheet exhibits a periodic moiré-cell superstructure due to lattice mismatch. Within a moiré cell, there are three distinct regions: fcc, hcp, and mound, in which the C{sub 6}-ring center is above a fcc site, a hcp site, and a surface Ru atom of Ru(0001), respectively. The adsorption energy of a Ru adatom is evaluated at specific sites in these distinct regions. We find the strongest binding at an adsorption site above a C atommore » in the fcc region, next strongest in the hcp region, then the fcc-hcp boundary (ridge) between these regions, and the weakest binding in the mound region. Behavior is similar to that observed from small-unit-cell calculations of Habenicht et al. [Top. Catal. 57, 69 (2014)], which differ from previous large-scale calculations. We determine the minimum-energy path for local diffusion near the center of the fcc region and obtain a local diffusion barrier of ∼0.48 eV. We also estimate a significantly lower local diffusion barrier in the ridge region. These barriers and information on the adsorption energy variation facilitate development of a realistic model for the global potential energy surface for Ru adatoms. This in turn enables simulation studies elucidating diffusion-mediated directed-assembly of Ru nanoclusters during deposition of Ru on G/Ru(0001)« less

On the performance of capillary barriers as landfill cover

NASA Astrophysics Data System (ADS)

Kämpf, M.; Montenegro, H.

Landfills and waste heaps require an engineered surface cover upon closure. The capping system can vary from a simple soil cover to multiple layers of earth and geosynthetic materials. Conventional design features a compacted soil layer, which suffers from drying out and cracking, as well as root and animal intrusion. Capillary barriers consisting of inclined fine-over-coarse soil layers are investigated as an alternative cover system. Under unsaturated conditions, the textural contrast delays vertical drainage by capillary forces. The moisture that builds up above the contact will flow downdip along the interface of the layers. Theoretical studies of capillary barriers have identified the hydraulic properties of the layers, the inclination angle, the length of the field and the infiltration rate as the fundamental characteristics of the system. However, it is unclear how these findings can lead to design criteria for capillary barriers. To assess the uncertainty involved in such approaches, experiments have been carried out in a 8 m long flume and on large scale test sites (40 m x 15 m). In addition, the ability of a numerical model to represent the relevant flow processes in capillary barriers has been examined.

Thermoelectric properties of periodic quantum structures in the Wigner-Rode formalism

NASA Astrophysics Data System (ADS)

Kommini, Adithya; Aksamija, Zlatan

2018-01-01

Improving the thermoelectric Seebeck coefficient, while simultaneously reducing thermal conductivity, is required in order to boost thermoelectric (TE) figure of merit (ZT). A common approach to improve the Seebeck coefficient is electron filtering where ‘cold’ (low energy) electrons are restricted from participating in transport by an energy barrier (Kim and Lundstrom 2011 J. Appl. Phys. 110 034511, Zide et al 2010 J. Appl. Phys. 108 123702). However, the impact of electron tunneling through thin barriers and resonant states on TE properties has been given less attention, despite the widespread use of quantum wells and superlattices (SLs) in TE applications. In our work, we develop a comprehensive transport model using the Wigner-Rode formalism. We include the full electronic bandstructure and all the relevant scattering mechanisms, allowing us to simulate both energy relaxation and quantum effects from periodic potential barriers. We study the impact of barrier shape on TE performance and find that tall, sharp barriers with small period lengths lead to the largest increase in both Seebeck coefficient and conductivity, thus boosting power factor and TE efficiency. Our findings are robust against additional elastic scattering such as atomic-scale roughness at side-walls of SL nanowires.

Barriers and Facilitators of Utilizing Research Among Nurses in Nepal.

PubMed

Kc, Srijana; Subramaniam, Prithwi Raj; Paudel, Sarita

2016-04-01

This study determined the perceived barriers to and facilitators of Nepalese nurses in utilizing research in the workplace. Evidence-based nursing practice provides the synergy for high-quality patient care, but it does not seem to be the case in underdeveloped countries, such as Nepal. A descriptive, cross-sectional study involving 97 nurses from Nepal was conducted. Data were collected using the BARRIERS Scale and a facilitator questionnaire. The top three barriers to research utilization in Nepalese nurses are (a) research reports and articles are not readily available (80.5%), (b) inadequate facilities for implementation (75.3%), and (c) research reports and articles are not published fast enough (71.6%). The top three facilitators perceived to encourage Nepalese nurses to utilize or participate in research are (a) initiation of nursing research projects (27.4%), (b) educational update on research methods (16.7%), and (c) provision of funding for research (15.5%). Findings from this study mirror the barriers to research utilization experienced by nurses in other countries. Macro- and micro-level support are needed to foster a culture of evidence-based practice among Nepalese nurses to empower them in making informed decisions based on research in providing quality patient care. Copyright 2016, SLACK Incorporated.

Role of Desolvation in Thermodynamics and Kinetics of Ligand Binding to a Kinase

PubMed Central

2015-01-01

Computer simulations are used to determine the free energy landscape for the binding of the anticancer drug Dasatinib to its src kinase receptor and show that before settling into a free energy basin the ligand must surmount a free energy barrier. An analysis based on using both the ligand-pocket separation and the pocket-water occupancy as reaction coordinates shows that the free energy barrier is a result of the free energy cost for almost complete desolvation of the binding pocket. The simulations further show that the barrier is not a result of the reorganization free energy of the binding pocket. Although a continuum solvent model gives the location of free energy minima, it is not able to reproduce the intermediate free energy barrier. Finally, it is shown that a kinetic model for the on rate constant in which the ligand diffuses up to a doorway state and then surmounts the desolvation free energy barrier is consistent with published microsecond time-scale simulations of the ligand binding kinetics for this system [Shaw, D. E. et al. J. Am. Chem. Soc.2011, 133, 9181−918321545110]. PMID:25516727

Tunnel barrier design in donor nanostructures defined by hydrogen-resist lithography

NASA Astrophysics Data System (ADS)

Pascher, Nikola; Hennel, Szymon; Mueller, Susanne; Fuhrer, Andreas

2016-08-01

A four-terminal donor quantum dot (QD) is used to characterize potential barriers between degenerately doped nanoscale contacts. The QD is fabricated by hydrogen-resist lithography on Si(001) in combination with n-type doping by phosphine. The four contacts have different separations (d = 9, 12, 16 and 29 nm) to the central 6 nm × 6 nm QD island, leading to different tunnel and capacitive coupling. Cryogenic transport measurements in the Coulomb-blockade (CB) regime are used to characterize these tunnel barriers. We find that field enhancement near the apex of narrow dopant leads is an important effect that influences both barrier breakdown and the magnitude of the tunnel current in the CB transport regime. From CB-spectroscopy measurements, we extract the mutual capacitances between the QD and the four contacts, which scale inversely with the contact separation d. The capacitances are in excellent agreement with numerical values calculated from the pattern geometry in the hydrogen resist. Furthermore, we show that by engineering the source-drain tunnel barriers to be asymmetric, we obtain a much simpler excited-state spectrum of the QD, which can be directly linked to the orbital single-particle spectrum.

Experimental and numerical investigations on reliability of air barrier on oil containment in flowing water.

PubMed

Lu, Jinshu; Xu, Zhenfeng; Xu, Song; Xie, Sensen; Wu, Haoxiao; Yang, Zhenbo; Liu, Xueqiang

2015-06-15

Air barriers have been recently developed and employed as a new type of oil containment boom. This paper presents systematic investigations on the reliability of air barriers on oil containments with the involvement of flowing water, which represents the commonly-seen shearing current in reality, by using both laboratory experiments and numerical simulations. Both the numerical and experimental investigations are carried out in a model scale. In the investigations, a submerged pipe with apertures is installed near the bottom of a tank to generate the air bubbles forming the air curtain; and, the shearing water flow is introduced by a narrow inlet near the mean free surface. The effects of the aperture configurations (including the size and the spacing of the aperture) and the location of the pipe on the effectiveness of the air barrier on preventing oil spreading are discussed in details with consideration of different air discharges and velocities of the flowing water. The research outcome provides a foundation for evaluating and/or improve the reliability of a air barrier on preventing spilled oil from further spreading. Copyright © 2015 Elsevier Ltd. All rights reserved.

Language support for linguistic minority chronic hepatitis B/C patients: an exploratory study of availability and clinicians' perceptions of language barriers in six European countries.

PubMed

Falla, Abby M; Veldhuijzen, Irene K; Ahmad, Amena A; Levi, Miriam; Richardus, Jan Hendrik

2017-02-20

Language support for linguistic minorities can improve patient safety, clinical outcomes and the quality of health care. Most chronic hepatitis B/C infections in Europe are detected among people born in endemic countries mostly in Africa, Asia and Central/Eastern Europe, groups that may experience language barriers when accessing health care services in their host countries. We investigated availability of interpreters and translated materials for linguistic minority hepatitis B/C patients. We also investigated clinicians' agreement that language barriers are explanations of three scenarios: the low screening uptake of hepatitis B/C screening, the lack of screening in primary care, and why cases do not reach specialist care. An online survey was developed, translated and sent to experts in five health care services involved in screening or treating viral hepatitis in six European countries: Germany, Hungary, Italy, the Netherlands, Spain and the United Kingdom (UK). The five areas of health care were: general practice/family medicine, antenatal care, health care for asylum seekers, sexual health and specialist secondary care. We measured availability using a three-point ordinal scale ('very common', 'variable or not routine' and 'rarely or never'). We measured agreement using a five-point Likert scale. We received 238 responses (23% response rate, N = 1026) from representatives in each health care field in each country. Interpreters are common in the UK, the Netherlands and Spain but variable or rare in Germany, Hungary and Italy. Translated materials are rarely/never available in Hungary, Italy and Spain but commonly or variably available in the Netherlands, Germany and the UK. Differing levels of agreement that language barriers explain the three scenarios are seen across the countries. Professionals in countries with most infrequent availability (Hungary and Italy) disagree strongest that language barriers are explanations. Our findings show pronounced differences between countries in availability of interpreters, differences that mirror socio-cultural value systems of 'difference-sensitive' and 'difference-blindness'. Improved language support is needed given the complex natural history of hepatitis B/C, the recognised barriers to screening and care, and the large undiagnosed burden among (potentially) linguistic minority migrant groups.

Sustainable practice change: Professionals' experiences with a multisectoral child health promotion programme in Sweden

PubMed Central

2011-01-01

Background New methods for prevention and health promotion and are constantly evolving; however, positive outcomes will only emerge if these methods are fully adopted and sustainable in practice. To date, limited attention has been given to sustainability of health promotion efforts. This study aimed to explore facilitators, barriers, and requirements for sustainability as experienced by professionals two years after finalizing the development and implementation of a multisectoral child health promotion programme in Sweden (the Salut programme). Initiated in 2005, the programme uses a 'Salutogenesis' approach to support health-promoting activities in health care, social services, and schools. Methods All professionals involved in the Salut Programme's pilot areas were interviewed between May and September 2009, approximately two years after the intervention package was established and implemented. Participants (n = 23) were midwives, child health nurses, dental hygienists/dental nurses, and pre-school teachers. Transcribed data underwent qualitative content analysis to illuminate perceived facilitators, barriers, and requirements for programme sustainability. Results The programme was described as sustainable at most sites, except in child health care. The perception of facilitators, barriers, and requirements were largely shared across sectors. Facilitators included being actively involved in intervention development and small-scale testing, personal values corresponding to programme intentions, regular meetings, working close with collaborators, using manuals and a clear programme branding. Existing or potential barriers included insufficient managerial involvement and support and perceived constraints regarding time and resources. In dental health care, barriers also included conflicting incentives for performance. Many facilitators and barriers identified by participants also reflected their perceptions of more general and forthcoming requirements for programme sustainability. Conclusions These results contribute to the knowledge of processes involved in achieving sustainability in health promotion initiatives. Facilitating factors include involving front-line professionals in intervention development and using small scale testing; however, the success of a programme requires paying attention to the role of managerial support and an overall supportive system. In summary, these results emphasise the importance for both practitioners and researchers to pay attention to parallel processes at different levels in multidisciplinary improvement efforts intended to ensure sustainable practice change. PMID:21426583

Early mobilization in critically ill patients: patients' mobilization level depends on health care provider's profession.

PubMed

Garzon-Serrano, Jaime; Ryan, Cheryl; Waak, Karen; Hirschberg, Ronald; Tully, Susan; Bittner, Edward A; Chipman, Daniel W; Schmidt, Ulrich; Kasotakis, Georgios; Benjamin, John; Zafonte, Ross; Eikermann, Matthias

2011-04-01

To evaluate whether the level of mobilization achieved and the barriers for progressing to the next mobilization level differ between nurses and physical therapists. Prospective, observational study. Twenty-bed surgical intensive care unit (SICU) of the Massachusetts General Hospital. Sixty-three critically ill patients. Physical therapists and nurses performed 179 mobilization therapies with 63 patients. Mobilization was defined as the process of enhancing mobility in the SICU, including bed mobility, edge of bed activities, transfers out of bed to a chair, and gait training; the mobilization level was measured on the SICU optimal mobilization scale, a 5-point (0-4) numerical rating scale. Patients' level of mobilization achieved by physical therapists was significantly higher compared with that achieved by nurses (2.3 ± 1.2 mean ± SD versus 1.2 ± 1.2, respectively P < .0001). Different barriers for mobilization were identified by physical therapists and nurses: hemodynamic instability (26% versus 12%, P = .03) and renal replacement therapy (12% versus 1%, P = .03) were barriers rated higher by nurses, whereas neurologic impairment was rated higher by physical therapists providers (18% versus 38%, P = .002). No mobilization-associated adverse events were observed in this study. This study showed that physical therapists mobilize their critically ill patients to higher levels compared with nurses. Nurse and physical therapists identify different barriers for mobilization. Routine involvement of physical therapists in directing mobilization treatment may promote early mobilization of critically ill patients. Copyright © 2011 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

Conformation and dynamics of polymer chains on dirty surfaces: A discrete-to-continuum approach

NASA Astrophysics Data System (ADS)

Foo, Grace M.; Pandey, R. B.

1998-07-01

A discrete-to-continuum (DC) simulation approach is introduced to study the statics and dynamics of polymer chains in two dimensions with quenched barriers, a dirty surface. In our DC hybrid approach, the large-scale relaxation of polymer chains on a discrete disordered lattice is followed by off-lattice simulation using a bead-spring chain model with a finitely extensible nonlinear elastic (FENE) potential for covalent bonds and Lennard-Jones (LJ) potential for nonbonded interactions. Segregation/folding of chains, which occurs at low temperatures (T=0.2, 1.0) with LJ interaction, becomes more difficult as the concentration of barriers increases, due to a screening effect of the barriers. In contrast to the chains' contraction at high temperature (i.e., T=5) and their collapse in athermal systems, chains are elongated on increasing the barrier concentration—a barrier-induced stretching. Variations of the root-mean-square (rms) displacements of the center of mass (Rcm) of the chains and their center node (Rcn) with time (t) show power-law behaviors (Rcm˜tν1, Rcn˜tν2) with nonuniversal exponents in the range ν1≃0.40-0.05 and ν2≃0.30-0.05, respectively, depending on temperature and barrier concentration. The radius of gyration (Rg) and the average bond length () expand on increasing the barrier concentration at low temperature and contract at high temperature, which is consistent with the variation of the width of the radial distribution function.

Nanoscale structural and chemical analysis of F-implanted enhancement-mode InAlN/GaN heterostructure field effect transistors

NASA Astrophysics Data System (ADS)

Tang, Fengzai; Lee, Kean B.; Guiney, Ivor; Frentrup, Martin; Barnard, Jonathan S.; Divitini, Giorgio; Zaidi, Zaffar H.; Martin, Tomas L.; Bagot, Paul A.; Moody, Michael P.; Humphreys, Colin J.; Houston, Peter A.; Oliver, Rachel A.; Wallis, David J.

2018-01-01

We investigate the impact of a fluorine plasma treatment used to obtain enhancement-mode operation on the structure and chemistry at the nanometer and atomic scales of an InAlN/GaN field effect transistor. The fluorine plasma treatment is successful in that enhancement mode operation is achieved with a +2.8 V threshold voltage. However, the InAlN barrier layers are observed to have been damaged by the fluorine treatment with their thickness being reduced by up to 50%. The treatment also led to oxygen incorporation within the InAlN barrier layers. Furthermore, even in the as-grown structure, Ga was unintentionally incorporated during the growth of the InAlN barrier. The impact of both the reduced barrier thickness and the incorporated Ga within the barrier on the transistor properties has been evaluated theoretically and compared to the experimentally determined two-dimensional electron gas density and threshold voltage of the transistor. For devices without fluorine treatment, the two-dimensional electron gas density is better predicted if the quaternary nature of the barrier is taken into account. For the fluorine treated device, not only the changes to the barrier layer thickness and composition, but also the fluorine doping needs to be considered to predict device performance. These studies reveal the factors influencing the performance of these specific transistor structures and highlight the strengths of the applied nanoscale characterisation techniques in revealing information relevant to device performance.

Barrier island morphodynamic classification based on lidar metrics for north Assateague Island, Maryland

USGS Publications Warehouse

Brock, John C.; Krabill, William; Sallenger, Asbury H.

2004-01-01

In order to reap the potential of airborne lidar surveys to provide geological information useful in understanding coastal sedimentary processes acting on various time scales, a new set of analysis methods are needed. This paper presents a multi-temporal lidar analysis of north Assateague Island, Maryland, and demonstrates the calculation of lidar metrics that condense barrier island morphology and morphological change into attributed linear features that may be used to analyze trends in coastal evolution. The new methods proposed in this paper are also of significant practical value, because lidar metric analysis reduces large volumes of point elevations into linear features attributed with essential morphological variables that are ideally suited for inclusion in Geographic Information Systems. A morphodynamic classification of north Assategue Island for a recent 10 month time period that is based on the recognition of simple patterns described by lidar change metrics is presented. Such morphodynamic classification reveals the relative magnitude and the fine scale alongshore variation in the importance of coastal changes over the study area during a defined time period. More generally, through the presentation of this morphodynamic classification of north Assateague Island, the value of lidar metrics in both examining large lidar data sets for coherent trends and in building hypotheses regarding processes driving barrier evolution is demonstrated

INSTITUTIONAL STAKEHOLDER PERCEPTIONS OF BARRIERS TO ADDICTION TREATMENT UNDER MEXICO’S DRUG POLICY REFORM

PubMed Central

Werb, Dan; Strathdee, Steffanie A.; Meza, Emilo; Gomez, Maria Gudelia Rangel; Palinkas, Lawrence; Medina-Mora, Maria Elena; Beletsky, Leo

2017-01-01

Background Mexico has experienced disproportionate drug-related harms given its role as a production and transit zone for illegal drugs destined primarily for the United States. In response, in 2009, the Mexican federal government passed legislation mandating pre-arrest diversion of drug-dependent individuals towards addiction treatment. However, this federal law was not specific about how the scale-up of the addiction treatment sector was to be operationalized. We therefore conducted in-depth qualitative interviews with key ‘interactors’ in fields affected by the federal legislation, including participants from the law enforcement, public health, addiction treatment, and governmental administration sectors. Among 19 participants from the municipal, state, and federal level, multiple barriers to policy reform were identified. First, there is a lack of institutional expertise to implement the reform. Second, the operationalization of the reform was not accompanied by a coordinated action plan. Third, the law is an unfunded mandate. Institutional barriers are likely hampering the implementation of Mexico’s policy reform. Addressing the concerns expressed by interactors through the scale up of services, the provision of increased training and education programs for stakeholders, and a coordinated action plan to operationalize the policy reform, are likely needed to improve the policy reform process. PMID:28278755

Chirp subbottom profile data collected in 2015 from the northern Chandeleur Islands, Louisiana

USGS Publications Warehouse

Forde, Arnell S.; DeWitt, Nancy T.; Fredericks, Jake J.; Miselis, Jennifer L.

2018-01-30

As part of the Barrier Island Evolution Research project, scientists from the U.S. Geological Survey (USGS) St. Petersburg Coastal and Marine Science Center conducted a nearshore geophysical survey around the northern Chandeleur Islands, Louisiana, in September 2015. The objective of the project is to improve the understanding of barrier island geomorphic evolution, particularly storm-related depositional and erosional processes that shape the islands over annual to interannual time scales (1–5 years). Collecting geophysical data can help researchers identify relations between the geologic history of the islands and their present day morphology and sediment distribution. High-resolution geophysical data collected along this rapidly changing barrier island system can provide a unique time-series dataset to further the analyses and geomorphological interpretations of this and other coastal systems, improving our understanding of coastal response and evolution over medium-term time scales (months to years). Subbottom profile data were collected in September 2015 offshore of the northern Chandeleur Islands, during USGS Field Activity Number 2015-331-FA. Data products, including raw digital chirp subbottom data, processed subbottom profile images, survey trackline map, navigation files, geographic information system data files and formal Federal Geographic Data Committee metadata, and Field Activity Collection System and operation logs are available for download.

Thermal activation of dislocations in large scale obstacle bypass

NASA Astrophysics Data System (ADS)

Sobie, Cameron; Capolungo, Laurent; McDowell, David L.; Martinez, Enrique

2017-08-01

Dislocation dynamics simulations have been used extensively to predict hardening caused by dislocation-obstacle interactions, including irradiation defect hardening in the athermal case. Incorporating the role of thermal energy on these interactions is possible with a framework provided by harmonic transition state theory (HTST) enabling direct access to thermally activated reaction rates using the Arrhenius equation, including rates of dislocation-obstacle bypass processes. Moving beyond unit dislocation-defect reactions to a representative environment containing a large number of defects requires coarse-graining the activation energy barriers of a population of obstacles into an effective energy barrier that accurately represents the large scale collective process. The work presented here investigates the relationship between unit dislocation-defect bypass processes and the distribution of activation energy barriers calculated for ensemble bypass processes. A significant difference between these cases is observed, which is attributed to the inherent cooperative nature of dislocation bypass processes. In addition to the dislocation-defect interaction, the morphology of the dislocation segments pinned to the defects play an important role on the activation energies for bypass. A phenomenological model for activation energy stress dependence is shown to describe well the effect of a distribution of activation energies, and a probabilistic activation energy model incorporating the stress distribution in a material is presented.

Current Limitations of Surgical Robotics in Reconstructive Plastic Microsurgery.

PubMed

Tan, Youri P A; Liverneaux, Philippe; Wong, Jason K F

2018-01-01

Surgical robots have the potential to provide surgeons with increased capabilities, such as removing physiologic tremor, scaling motion and increasing manual dexterity. Several surgical specialties have subsequently integrated robotic surgery into common clinical practice. Plastic and reconstructive microsurgical procedures have not yet  benefitted significantly from technical developments observed over the last two decades. Several studies have successfully demonstrated the feasibility of utilising surgical robots in plastic surgery procedures, yet limited work has been done to identify and analyse current barriers that have prevented wide-scale adaptation of surgical robots for microsurgery. Therefore, a systematic review using PubMed, MEDLINE, Embase and Web of Science databases was performed, in order to evaluate current state of surgical robotics within the field of reconstructive microsurgery and their limitations. Despite the theoretical potential of surgical robots, current commercially available robotic systems are suboptimal for plastic or reconstructive microsurgery. Absence of bespoke microsurgical instruments, increases in operating time, and high costs associated with robotic-assisted provide a barrier to using such systems effectively for reconstructive microsurgery. Consequently, surgical robots provide currently little overall advantage over conventional microsurgery. Nevertheless, if current barriers can be addressed and systems are specifically designed for microsurgery, surgical robots may have the potential of meaningful impact on clinical outcomes within  this surgical subspeciality.

Current Limitations of Surgical Robotics in Reconstructive Plastic Microsurgery

PubMed Central

Tan, Youri P. A.; Liverneaux, Philippe; Wong, Jason K. F.

2018-01-01

Surgical robots have the potential to provide surgeons with increased capabilities, such as removing physiologic tremor, scaling motion and increasing manual dexterity. Several surgical specialties have subsequently integrated robotic surgery into common clinical practice. Plastic and reconstructive microsurgical procedures have not yet  benefitted significantly from technical developments observed over the last two decades. Several studies have successfully demonstrated the feasibility of utilising surgical robots in plastic surgery procedures, yet limited work has been done to identify and analyse current barriers that have prevented wide-scale adaptation of surgical robots for microsurgery. Therefore, a systematic review using PubMed, MEDLINE, Embase and Web of Science databases was performed, in order to evaluate current state of surgical robotics within the field of reconstructive microsurgery and their limitations. Despite the theoretical potential of surgical robots, current commercially available robotic systems are suboptimal for plastic or reconstructive microsurgery. Absence of bespoke microsurgical instruments, increases in operating time, and high costs associated with robotic-assisted provide a barrier to using such systems effectively for reconstructive microsurgery. Consequently, surgical robots provide currently little overall advantage over conventional microsurgery. Nevertheless, if current barriers can be addressed and systems are specifically designed for microsurgery, surgical robots may have the potential of meaningful impact on clinical outcomes within  this surgical subspeciality. PMID:29740585

Role of the dielectric for the charging dynamics of the dielectric/barrier interface in AlGaN/GaN based metal-insulator-semiconductor structures under forward gate bias stress

NASA Astrophysics Data System (ADS)

Lagger, P.; Steinschifter, P.; Reiner, M.; Stadtmüller, M.; Denifl, G.; Naumann, A.; Müller, J.; Wilde, L.; Sundqvist, J.; Pogany, D.; Ostermaier, C.

2014-07-01

The high density of defect states at the dielectric/III-N interface in GaN based metal-insulator-semiconductor structures causes tremendous threshold voltage drifts, ΔVth, under forward gate bias conditions. A comprehensive study on different dielectric materials, as well as varying dielectric thickness tD and barrier thickness tB, is performed using capacitance-voltage analysis. It is revealed that the density of trapped electrons, ΔNit, scales with the dielectric capacitance under spill-over conditions, i.e., the accumulation of a second electron channel at the dielectric/AlGaN barrier interface. Hence, the density of trapped electrons is defined by the charging of the dielectric capacitance. The scaling behavior of ΔNit is explained universally by the density of accumulated electrons at the dielectric/III-N interface under spill-over conditions. We conclude that the overall density of interface defects is higher than what can be electrically measured, due to limits set by dielectric breakdown. These findings have a significant impact on the correct interpretation of threshold voltage drift data and are of relevance for the development of normally off and normally on III-N/GaN high electron mobility transistors with gate insulation.

Development and testing of nurses' perceptions of the use of hydrotherapy in labor questionnaire.

PubMed

Stark, Mary Ann; Miller, Michael G

2010-01-01

While effective for labor pain, hydrotherapy is not often used. The purpose of this study was to develop and test an instrument of nurses' perceptions of the barriers to the use of hydrotherapy in labor. Following generation of items and review by content experts, the Nurses' Perceptions of the Use of Hydrotherapy in Labor (NPUHL) questionnaire was administered to 65 intrapartum nurses (phase I) and to 401 nurses (phase II). In phase I, the mean score of the NPUHL was significantly and negatively correlated with the Labor Support Scale (r = -.30, p = .016), indicating that nurses who demonstrated more labor-supportive behaviors also perceived fewer barriers to the use of hydrotherapy in labor. In phase II, exploratory factor analysis revealed five factors: Health Care Environment, Knowledge and Beliefs, Personal Concerns, Effort Required for Hydrotherapy, and Technology. There was a significant negative correlation (r = -.61) between use of hydrotherapy and the total NPUHL score and those of its subscales (r = -.12 to -.61); nurses with access to hydrotherapy tubs perceived fewer barriers to hydrotherapy than nurses without (t = 9.71, df= 387, p < .01). For the revised 30-item NPUHL, Cronbach's alpha was .93, and subscale alphas ranged from .58 to .93. The 30-item NPUHL scale demonstrated evidence of good initial reliability and validity.

The effects of magnetic and mechanical microstructures on the twinning stress in Ni-Mn-Ga

NASA Astrophysics Data System (ADS)

Faran, Eilon; Benichou, Itamar; Givli, Sefi; Shilo, Doron

2015-12-01

The ferromagnetic 10M Ni-Mn-Ga alloy exhibits complex magnetic and mechanical microstructures, which are expected to form barriers for motion of macro twin boundaries. Here, the contributions of both microstructures to the magnitude of the twinning stress property are investigated experimentally. A series of uniaxial loading-unloading curves are taken under different orientation angles of a constant magnetic field. The different 180 ° magnetic domains microstructures that are formed across the twin boundary in each case are visualised using a magneto optical film. Analysis of the different loading curves and the corresponding magnetic microstructures show that the latter does not contribute to the barriers for twin boundary motion. In accordance, the internal resisting stress for twin boundary motion under any magnetic field can be taken as the twinning stress measured in the absence of an external field. In addition, a statistical analysis of the fine features in the loading profiles reveals that the barrier for twinning is associated with a μ m sized characteristic length scale. This length scale corresponds to the typical thickness of micro-twinning laminates that constitute a mechanical microstructure. These findings indicate that the magnitude of the twinning stress in 10M Ni-Mn-Ga is determined by the characteristic fine twinned mechanical microstructure of this alloy.

Ultrathin Ceramic Membranes as Scaffolds for Functional Cell Coculture Models on a Biomimetic Scale

PubMed Central

Jud, Corinne; Ahmed, Sher; Müller, Loretta; Kinnear, Calum; Vanhecke, Dimitri; Umehara, Yuki; Frey, Sabine; Liley, Martha; Angeloni, Silvia; Petri-Fink, Alke; Rothen-Rutishauser, Barbara

2015-01-01

Abstract Epithelial tissue serves as an interface between biological compartments. Many in vitro epithelial cell models have been developed as an alternative to animal experiments to answer a range of research questions. These in vitro models are grown on permeable two-chamber systems; however, commercially available, polymer-based cell culture inserts are around 10 μm thick. Since the basement membrane found in biological systems is usually less than 1 μm thick, the 10-fold thickness of cell culture inserts is a major limitation in the establishment of realistic models. In this work, an alternative insert, accommodating an ultrathin ceramic membrane with a thickness of only 500 nm (i.e., the Silicon nitride Microporous Permeable Insert [SIMPLI]-well), was produced and used to refine an established human alveolar barrier coculture model by both replacing the conventional inserts with the SIMPLI-well and completing it with endothelial cells. The structural–functional relationship of the model was evaluated, including the translocation of gold nanoparticles across the barrier, revealing a higher translocation if compared to corresponding polyethylene terephthalate (PET) membranes. This study demonstrates the power of the SIMPLI-well system as a scaffold for epithelial tissue cell models on a truly biomimetic scale, allowing construction of more functionally accurate models of human biological barriers. PMID:26713225

Novel Approach to Conducting Blast Load Analyses Using Abaqus/Explicit-CEL

DTIC Science & Technology

2010-05-01

versus uncased, effects of afterburning , angle of incidence with respect to incoming shock, nearby geometry/barriers interacting with the shock...2. Blast parameters as a function of scaled distance – from TNT air blast data (DOE/TIC-11268, 1981). Due to inertial effects, the volume of air...positive phase duration) can be determined for a particular scaled distance. Figure 2 was generated from TNT air blast data for bare, spherical charges

Dynamic simulation of storm-driven barrier island morphology under future sea level rise

NASA Astrophysics Data System (ADS)

Passeri, D. L.; Long, J.; Plant, N. G.; Bilskie, M. V.; Hagen, S. C.

2016-12-01

The impacts of short-term processes such as tropical and extratropical storms have the potential to alter barrier island morphology. On the event scale, the effects of storm-driven morphology may result in damage or loss of property, infrastructure and habitat. On the decadal scale, the combination of storms and sea level rise (SLR) will evolve barrier islands. The effects of SLR on hydrodynamics and coastal morphology are dynamic and inter-related; nonlinearities in SLR can cause larger peak surges, lengthier inundation times and additional inundated land, which may result in increased erosion, overwash or breaching along barrier islands. This study uses a two-dimensional morphodynamic model (XBeach) to examine the response of Dauphin Island, AL to storm surge under future SLR. The model is forced with water levels and waves provided by a large-domain hydrodynamic model. A historic validation of hurricanes Ivan and Katrina indicates the model is capable of predicting morphologic response with high skill (0.5). The validated model is used to simulate storm surge driven by Ivan and Katrina under four future SLR scenarios, ranging from 20 cm to 2 m. Each SLR scenario is implemented using a static or "bathtub" approach (in which water levels are increased linearly by the amount of SLR) versus a dynamic approach (in which SLR is applied at the open ocean boundary of the hydrodynamic model and allowed to propagate through the domain as guided by the governing equations). Results illustrate that higher amounts of SLR result in additional shoreline change, dune erosion, overwash and breaching. Compared to the dynamic approach, the static approach over-predicts inundation, dune erosion, overwash and breaching of the island. Overall, results provide a better understanding of the effects of SLR on storm-driven barrier island morphology and support a paradigm shift away from the "bathtub" approach, towards considering the integrated, dynamic effects of SLR.

Sub-barrier quasifission in heavy element formation reactions with deformed actinide target nuclei

NASA Astrophysics Data System (ADS)

Hinde, D. J.; Jeung, D. Y.; Prasad, E.; Wakhle, A.; Dasgupta, M.; Evers, M.; Luong, D. H.; du Rietz, R.; Simenel, C.; Simpson, E. C.; Williams, E.

2018-02-01

Background: The formation of superheavy elements (SHEs) by fusion of two massive nuclei is severely inhibited by the competing quasifission process. Low excitation energies favor SHE survival against fusion-fission competition. In "cold" fusion with spherical target nuclei near 208Pb, SHE yields are largest at beam energies significantly below the average capture barrier. In "hot" fusion with statically deformed actinide nuclei, this is not the case. Here the elongated deformation-aligned configurations in sub-barrier capture reactions inhibits fusion (formation of a compact compound nucleus), instead favoring rapid reseparation through quasifission. Purpose: To determine the probabilities of fast and slow quasifission in reactions with prolate statically deformed actinide nuclei, through measurement and quantitative analysis of the dependence of quasifission characteristics at beam energies spanning the average capture barrier energy. Methods: The Australian National University Heavy Ion Accelerator Facility and CUBE fission spectrometer have been used to measure fission and quasifission mass and angle distributions for reactions with projectiles from C to S, bombarding Th and U target nuclei. Results: Mass-asymmetric quasifission occurring on a fast time scale, associated with collisions with the tips of the prolate actinide nuclei, shows a rapid increase in probability with increasing projectile charge, the transition being centered around projectile atomic number ZP=14 . For mass-symmetric fission events, deviations of angular anisotropies from expectations for fusion fission, indicating a component of slower quasifission, suggest a similar transition, but centered around ZP˜8 . Conclusions: Collisions with the tips of statically deformed prolate actinide nuclei show evidence for two distinct quasifission processes of different time scales. Their probabilities both increase rapidly with the projectile charge. The probability of fusion can be severely suppressed by these two quasifission processes, since the sub-barrier heavy element yield is likely to be determined by the product of the probabilities of surviving each quasifission process.

What works in practice: user and provider perspectives on the acceptability, affordability, implementation, and impact of a family-based intervention for child overweight and obesity delivered at scale

PubMed Central

2014-01-01

Background As part of a study considering the impact of a child weight management programme when rolled out at scale following an RCT, this qualitative study focused on acceptability and implementation for providers and for families taking part. Methods Participants were selected on the basis of a maximum variation sample providing a range of experiences and social contexts. Qualitative interviews were conducted with 29 professionals who commissioned or delivered the programme, and 64 individuals from 23 families in 3 English regions. Topic guides were used as a tool rather than a rule, enabling participants to construct a narrative about their experiences. Transcripts were analysed using framework analysis. Results Practical problems such as transport, work schedules and competing demands on family time were common barriers to participation. Delivery partners often put considerable efforts into recruiting, retaining and motivating families, which increased uptake but also increased cost. Parents and providers valued skilled delivery staff. Some providers made adaptations to meet local social and cultural needs. Both providers and parents expressed concerns about long term outcomes, and how this was compromised by an obesogenic environment. Concerns about funding together with barriers to uptake and engagement could translate into barriers to commissioning. Where these barriers were not experienced, commissioners were enthusiastic about continuing the programme. Conclusions Most families felt that they had gained something from the programme, but few felt that it had ‘worked’ for them. The demands on families including time and emotional work were experienced as difficult. For commissioners, an RCT with positive results was an important driver, but family barriers, alongside concerns about recruitment and retention, a desire for local adaptability with qualified motivated staff, and funding changes discouraged some from planning to use the intervention in future. PMID:24938729

Development and validation of the Evidence Based Medicine Questionnaire (EBMQ) to assess doctors' knowledge, practice and barriers regarding the implementation of evidence-based medicine in primary care.

PubMed

Hisham, Ranita; Ng, Chirk Jenn; Liew, Su May; Lai, Pauline Siew Mei; Chia, Yook Chin; Khoo, Ee Ming; Hanafi, Nik Sherina; Othman, Sajaratulnisah; Lee, Ping Yein; Abdullah, Khatijah Lim; Chinna, Karuthan

2018-06-23

Evidence-Based Medicine (EBM) integrates best available evidence from literature and patients' values, which then informs clinical decision making. However, there is a lack of validated instruments to assess the knowledge, practice and barriers of primary care physicians in the implementation of EBM. This study aimed to develop and validate an Evidence-Based Medicine Questionnaire (EBMQ) in Malaysia. The EBMQ was developed based on a qualitative study, literature review and an expert panel. Face and content validity was verified by the expert panel and piloted among 10 participants. Primary care physicians with or without EBM training who could understand English were recruited from December 2015 to January 2016. The EBMQ was administered at baseline and two weeks later. A higher score indicates better knowledge, better practice of EBM and less barriers towards the implementation of EBM. We hypothesized that the EBMQ would have three domains: knowledge, practice and barriers. The final version of the EBMQ consists of 80 items: 62 items were measured on a nominal scale, 22 items were measured on a 5 point Likert-scale. Flesch reading ease was 61.2. A total of 343 participants were approached; of whom 320 agreed to participate (response rate = 93.2%). Factor analysis revealed that the EBMQ had eight domains after 13 items were removed: "EBM websites", "evidence-based journals", "types of studies", "terms related to EBM", "practice", "access", "patient preferences" and "support". Cronbach alpha for the overall EBMQ was 0.909, whilst the Cronbach alpha for the individual domain ranged from 0.657-0.940. The EBMQ was able to discriminate between doctors with and without EBM training for 24 out of 42 items. At test-retest, kappa values ranged from 0.155 to 0.620. The EBMQ was found to be a valid and reliable instrument to assess the knowledge, practice and barriers towards the implementation of EBM among primary care physicians in Malaysia.

Exploring barriers and enablers for scaling up a community-based grain bank intervention for improved infant and young child feeding in Ethiopia: A qualitative process evaluation.

PubMed

Sako, Binta; Leerlooijer, Joanne N; Lelisa, Azeb; Hailemariam, Abebe; Brouwer, Inge D; Tucker Brown, Amal; Osendarp, Saskia J M

2018-04-01

Child malnutrition remains high in Ethiopia, and inadequate complementary feeding is a contributing factor. In this context, a community-based intervention was designed to provide locally made complementary food for children 6-23 months, using a bartering system, in four Ethiopian regions. After a pilot phase, the intervention was scaled up from 8 to 180 localities. We conducted a process evaluation to determine enablers and barriers for the scaling up of this intervention. Eight study sites were selected to perform 52 key informant interviews and 31 focus group discussions with purposely selected informants. For analysis, we used a framework describing six elements of successful scaling up: socio-political context, attributes of the intervention, attributes of the implementers, appropriate delivery strategy, the adopting community, and use of research to inform the scale-up process. A strong political will, alignment of the intervention with national priorities, and integration with the health care system were instrumental in the scaling up. The participatory approach in decision-making reinforced ownership at community level, and training about complementary feeding motivated mothers and women's groups to participate. However, the management of the complex intervention, limited human resources, and lack of incentives for female volunteers proved challenging. In the bartering model, the barter rate was accepted, but the bartering was hindered by unavailability of cereals and limited financial and material resources to contribute, threatening the project's sustainability. Scaling up strategies for nutrition interventions require sufficient time, thorough planning, and assessment of the community's capacity to contribute human, financial, and material resources. © 2017 The Authors. Maternal and Child Nutrition Published by John Wiley & Sons, Ltd.

Preferences for and Barriers to Formal and Informal Athletic Training Continuing Education Activities

PubMed Central

Armstrong, Kirk J.; Weidner, Thomas G.

2011-01-01

Context: Our previous research determined the frequency of participation and perceived effect of formal and informal continuing education (CE) activities. However, actual preferences for and barriers to CE must be characterized. Objective: To determine the types of formal and informal CE activities preferred by athletic trainers (ATs) and barriers to their participation in these activities. Design: Cross-sectional study. Setting: Athletic training practice settings. Patients or Other Participants: Of a geographically stratified random sample of 1000 ATs, 427 ATs (42.7%) completed the survey. Main Outcome Measure(s): As part of a larger study, the Survey of Formal and Informal Athletic Training Continuing Education Activities (FIATCEA) was developed and administered electronically. The FIATCEA consists of demographic characteristics and Likert scale items (1 = strongly disagree, 5 = strongly agree) about preferred CE activities and barriers to these activities. Internal consistency of survey items, as determined by Cronbach α, was 0.638 for preferred CE activities and 0.860 for barriers to these activities. Descriptive statistics were computed for all items. Differences between respondent demographic characteristics and preferred CE activities and barriers to these activities were determined via analysis of variance and dependent t tests. The α level was set at .05. Results: Hands-on clinical workshops and professional networking were the preferred formal and informal CE activities, respectively. The most frequently reported barriers to formal CE were the cost of attending and travel distance, whereas the most frequently reported barriers to informal CE were personal and job-specific factors. Differences were noted between both the cost of CE and travel distance to CE and all other barriers to CE participation (F1,411 = 233.54, P < .001). Conclusions: Overall, ATs preferred formal CE activities. The same barriers (eg, cost, travel distance) to formal CE appeared to be universal to all ATs. Informal CE was highly valued by ATs because it could be individualized. PMID:22488195

"I don't have the heart": a qualitative study of barriers to and facilitators of physical activity for people with coronary heart disease and depressive symptoms.

PubMed

Rogerson, Michelle C; Murphy, Barbara M; Bird, Stephen; Morris, Tony

2012-11-30

Physical activity has been shown to reduce depression in people with coronary heart disease (CHD), however many people with CHD do not engage in sufficient levels of physical activity to reap its positive effects. People with depression and CHD are at particular risk of non-adherence to physical activity. Little is known about the barriers to and facilitators of physical activity for people with CHD and depressive symptoms. Using qualitative interviews, the aim of this study was to explore the barriers to and facilitators of physical activity for cardiac patients with depressive symptoms. Fifteen participants with CHD and depressive symptoms (assessed using the Cardiac Depression Scale) participated in in-depth semi-structured interviews. The interviews were focussed on investigating participants' experiences of physical activity since their cardiac event. Interviews were content analysed to determine major themes. Participants identified a number of barriers to and facilitators of physical activity. Barriers included having negative perceptions towards health and life changes as a result of the cardiac event, having low mood and low motivation to exercise, feeling physically restricted towards or fearful of exercise, lacking knowledge regarding exercise and perceiving external barriers. Facilitators included having a reason for exercising, being able to identify the psychological benefits of exercise, having positive social support and using psychological strategies. 'Inactive' participants reported more barriers and fewer facilitators than did 'active' participants. The barriers reported in this study were highly salient for a number of participants. Health professionals and researchers can use this information to assist people with CHD and depressive symptoms to identify and possibly overcome barriers to physical activity. Relevant barriers and facilitators could be taken into account to increase their effectiveness when designing interventions to encourage physical activity maintenance in this population.

Study of Barrier to Help Seeking and its Relationships with Disability in Patients with Headache

PubMed Central

John, Deepa; Sundarmurthy, Harsha; Rathod, Harshal; Rathod, Snehal

2016-01-01

Introduction Headache is among the first three most prevalent disorders with a wide treatment gap due to barriers in help seeking. Headache has been associated with disability. However, the relationship of barriers to help-seeking and disability are unexplored. Aim To find out the barriers to help seeking and its relationship with headache related disability in patients with headache. Materials and Methods In this hospital based cross-sectional study, 200 consecutive subjects with headache attending a tertiary care centre were recruited as per selection criteria and assessed with Sociodemographic & Clinical Proforma, Mini International Neuropsychiatric Interview (MINI), Barriers to Help Seeking Scale (BHSS), The Henry Ford Hospital Headache Disability Inventory (HDI). Results High mean score was observed on BHSS subscale need for control and self reliance (19.45; SD ±9.66) and minimizing problem and resignation (10.02; SD ±6.98). Mean score on the HDI was 25.65 (SD ± 14.09). Socioeconomic status of the patient was statistically significant and positively associated with need for control and self reliance (p=0.035), concrete barriers and distrust of care givers (p=0.039), emotional control (p=0.005), and privacy (p=0.002). Occupational status had significant association with need for control and self-reliance (p=0.01), minimizing problem and resignation (p=0.033), and emotional control (p=0.006). Score on hospital headache disability inventory significantly predicted the value of score on concrete barriers and distrust of caregivers domain of HDI (p=0.001). Conclusion Autonomy and under estimation of seriousness of headache are common barriers to help seeking. Pattern of help seeking barriers may vary with socio-economic status and occupational status, while disability varies with gender and severity of headache. Headache associated disability is positively associated with concrete barriers. PMID:27891430

Mining twitter to understand the smoking cessation barriers.

PubMed

Krittanawong, Chayakrit; Wang, Zhen

2017-10-26

Smoking cessation is challenging and lack of positive support is a known major barrier to quitting cigarettes. Previous studies have suggested that social influences might increase smokers' awareness of social norms for appropriate behavior, which might lead to smoking cessation. Although social media use is increasing among young adults in the United States, research on the relationship between social media use and smoking cessation is lacking. Twitter has provided a rich source of information for researchers, but no overview exists as to how the field uses Twitter in smoking cessation research. To the best of our knowledge, this study conducted a data mining analysis of Twitter to assess barriers to smoking cessation. In conclusion, Twitter is a cost-effective tool with the potential to disseminate information on the benefits of smoking cessation and updated research to the Twitter community on a global scale.

Detecting Small-Scale topographic Changes and Relict Geomorphic Features on Barrier Islands using SAR

NASA Technical Reports Server (NTRS)

Gibeaut, James C.; Gutierrez, Roberto; Slatton, K. Clint; Crawford, Melba M.

1996-01-01

The shapes and elevations of barrier islands may change dramatically over a short period of time such as during a storm. Even between storms, sediment is constantly shifting to and from these islands and between different areas of the islands at varying rates and in varying amounts. Coastal scientists and engineers, however, are currently unable to measure these changes occurring over an entire barrier island at once. This three-year project, which is funded by NASA and jointly conducted by the Bureau of Economic Geology and the Center for Space Research at The University of Texas at Austin, is designed to overcome this problem by developing the use of interferometry from airborne synthetic aperture radar (AIRSAR) to detect changes in coastal topography. Surrogate measures of topography observed in fully polarimetric AIRSAR are also being investigated.

Oxygen plasma etching of graphene: A first-principles dynamical inspection of the reaction mechanisms and related activation barriers

NASA Astrophysics Data System (ADS)

Koizumi, Kenichi; Boero, Mauro; Shigeta, Yasuteru; Oshiyama, Atsushi; Dept. of Applied Physics Team; Institute of Physics and Chemistry of Strasbourg (IPCMS) Collaboration; Department Of Materials Engineering Science Collaboration

2013-03-01

Oxygen plasma etching is a crucial step in the fabrication of electronic circuits and has recently received a renovated interest in view of the realization of carbon-based nanodevices. In an attempt at unraveling the atomic-scale details and to provide guidelines for the control of the etching processes mechanisms, we inspected the possible reaction pathways via reactive first principles simulations. These processes involve breaking and formation of several chemical bonds and are characterized by different free-energy barriers. Free-energy sampling techniques (metadynamics and blue moon), used to enhance the standard Car-Parrinello molecular dynamics, provide us a detailed microscopic picture of the etching of graphene surfaces and a comprehensive scenario of the activation barriers involved in the various steps. MEXT, Japan - contract N. 22104005

Perceived barriers to physician-scientist careers among female undergraduate medical students at the College of Medicine - Alfaisal University: a Saudi Arabian perspective.

PubMed

Abu-Zaid, Ahmed; Altinawi, Basmah

2014-04-01

At present, only a negligible number of matriculating and graduating female medical students express interest in physician-scientist careers. The aim of this study is to explore the perceived barriers towards pursuing physician-scientist careers by female undergraduate medical students at College of Medicine - Alfaisal University, Saudi Arabia. An online, anonymous, self-rating survey was administered. The survey assessed students' perceived barriers towards potential physician-scientist careers by responding to typical 5-point Likert scale statements. One hundred sixteen students (116/171) participated in the survey with a 67.8% response rate. The top three barriers to such physician-scientist careers were greater preference towards patient care than research (75%), lack of conviction as regards merging a fruitful research profession with satisfying motherhood life (52.6%) and paucity of recognizing successful and well-known female physician-scientist role models in the country (48.3%). Our results showed that the perceived barriers to physician-scientist careers by College of Medicine - Alfaisal University's female undergraduate medical students were largely identical to the Western literature with few differences and more influence of cultural reasons. It is crucial for medical educators in Saudi Arabia to work on mechanisms that stimulate female students' interest in research and resolve all barriers that stand in the face of students towards considering physician-scientist careers.

PubMed Central

AHADI, H.; JOMEHRI, F.; RAHGOZAR, M.

2013-01-01

Summary Objectives. Despite advances in screening and treatment during past several Decades, cervical cancer remains a major health problem for Iranian women. Recent researches have focused on factors related to development of health behavior in an effort to design effective early interventions. The current study aimed to investigate the role of attachment styles on cervix cancer screening barriers among women of BandarAbbas-Iran. Methods. In an analytic-cross sectional study, 681 women aged 21-65 referring to health centers were selected randomly and after completing written informed consents were investigated by Revised Adult Attachment Scale (RAAS) (Collins and Read), Pap smear screening barriers and demographic data questionnaire. The data were analyzed by Pearson correlation coefficient, linear regressions and chi-square test. Results. The results showed significant association between attachment styles and screening barriers. There was a negative significant relation between secure attachment style and screening barriers and there was a positive significant association between insecure attachment style (anxiety and avoidant) and screening barriers. The regression analysis indicated that insecure attachment style (avoidant) were predictors of barriers to the Pap smear screening test in this regard. There was a significant association between age and residential area and participation in Pap smear test. Conclusions. Insecure attachment style is associated with hazardous risk behaviors and these results can be useful for health service providers in preventive planning of screening and identification of people susceptible to risk and the design of the intervention. PMID:24779284

Cement kiln dust (CKD)-filter sand permeable reactive barrier for the removal of Cu(II) and Zn(II) from simulated acidic groundwater.

PubMed

Sulaymon, Abbas H; Faisal, Ayad A H; Khaliefa, Qusey M

2015-10-30

The hydraulic conductivity and breakthrough curves of copper and zinc contaminants were measured in a set of continuous column experiments for 99 days using cement kiln dust (CKD)-filter sand as the permeable reactive barrier. The results of these experiments proved that the weight ratios of the cement kiln dust-filter sand (10:90 and 20:80) are adequate in preventing the loss of reactivity and hydraulic conductivity and, in turn, avoiding reduction in the groundwater flow. These results reveal a decrease in the hydraulic conductivity, which can be attributed to an accumulation of most of the quantity of the contaminant masses in the first sections of the column bed. Breakthrough curves for the description of the temporal contaminant transport within the barrier were found to be more representative by the Belter-Cussler-Hu and Yan models based on the coefficient of determination and Nash-Sutcliffe efficiency. The longevity of the barrier was simulated for the field scale, based on the laboratory column tests and the values verified that cement kiln dust can be effectively used in the future, as the reactive material in permeable reactive barrier technology. These results signify that the longevity of the barrier is directly proportional to its thickness and inversely to the percentage of the CKD used. Copyright © 2015 Elsevier B.V. All rights reserved.

Impacts and recovery from severe tropical cyclone Yasi on the Great Barrier Reef.

PubMed

Beeden, Roger; Maynard, Jeffrey; Puotinen, Marjetta; Marshall, Paul; Dryden, Jen; Goldberg, Jeremy; Williams, Gareth

2015-01-01

Full recovery of coral reefs from tropical cyclone (TC) damage can take decades, making cyclones a major driver of habitat condition where they occur regularly. Since 1985, 44 TCs generated gale force winds (≥17 metres/second) within the Great Barrier Reef Marine Park (GBRMP). Of the hurricane strength TCs (≥H1-Saffir Simpson scale; ≥ category 3 Australian scale), TC Yasi (February, 2011) was the largest. In the weeks after TC Yasi crossed the GBRMP, participating researchers, managers and rangers assessed the extent and severity of reef damage via 841 Reef Health and Impact Surveys at 70 reefs. Records were scaled into five damage levels representing increasingly widespread colony-level damage (1, 2, 3) and reef structural damage (4, 5). Average damage severity was significantly affected by direction (north vs south of the cyclone track), reef shelf position (mid-shelf vs outer-shelf) and habitat type. More outer-shelf reefs suffered structural damage than mid-shelf reefs within 150 km of the track. Structural damage spanned a greater latitudinal range for mid-shelf reefs than outer-shelf reefs (400 vs 300 km). Structural damage was patchily distributed at all distances, but more so as distance from the track increased. Damage extended much further from the track than during other recent intense cyclones that had smaller circulation sizes. Just over 15% (3,834 km2) of the total reef area of the GBRMP is estimated to have sustained some level of coral damage, with ~4% (949 km2) sustaining a degree of structural damage. TC Yasi likely caused the greatest loss of coral cover on the GBR in a 24-hour period since 1985. Severely impacted reefs have started to recover; coral cover increased an average of 4% between 2011 and 2013 at re-surveyed reefs. The in situ assessment of impacts described here is the largest in scale ever conducted on the Great Barrier Reef following a reef health disturbance.

Impacts and Recovery from Severe Tropical Cyclone Yasi on the Great Barrier Reef

PubMed Central

Beeden, Roger; Maynard, Jeffrey; Puotinen, Marjetta; Marshall, Paul; Dryden, Jen; Goldberg, Jeremy; Williams, Gareth

2015-01-01

Full recovery of coral reefs from tropical cyclone (TC) damage can take decades, making cyclones a major driver of habitat condition where they occur regularly. Since 1985, 44 TCs generated gale force winds (≥17 metres/second) within the Great Barrier Reef Marine Park (GBRMP). Of the hurricane strength TCs (≥H1—Saffir Simpson scale; ≥ category 3 Australian scale), TC Yasi (February, 2011) was the largest. In the weeks after TC Yasi crossed the GBRMP, participating researchers, managers and rangers assessed the extent and severity of reef damage via 841 Reef Health and Impact Surveys at 70 reefs. Records were scaled into five damage levels representing increasingly widespread colony-level damage (1, 2, 3) and reef structural damage (4, 5). Average damage severity was significantly affected by direction (north vs south of the cyclone track), reef shelf position (mid-shelf vs outer-shelf) and habitat type. More outer-shelf reefs suffered structural damage than mid-shelf reefs within 150 km of the track. Structural damage spanned a greater latitudinal range for mid-shelf reefs than outer-shelf reefs (400 vs 300 km). Structural damage was patchily distributed at all distances, but more so as distance from the track increased. Damage extended much further from the track than during other recent intense cyclones that had smaller circulation sizes. Just over 15% (3,834 km2) of the total reef area of the GBRMP is estimated to have sustained some level of coral damage, with ~4% (949 km2) sustaining a degree of structural damage. TC Yasi likely caused the greatest loss of coral cover on the GBR in a 24-hour period since 1985. Severely impacted reefs have started to recover; coral cover increased an average of 4% between 2011 and 2013 at re-surveyed reefs. The in situ assessment of impacts described here is the largest in scale ever conducted on the Great Barrier Reef following a reef health disturbance. PMID:25874718

Electromagnetic Saturation of Angstrom-Sized Quantum Barriers at Terahertz Frequencies

NASA Astrophysics Data System (ADS)

Bahk, Young-Mi; Kang, Bong Joo; Kim, Yong Seung; Kim, Joon-Yeon; Kim, Won Tae; Kim, Tae Yun; Kang, Taehee; Rhie, Jiyeah; Han, Sanghoon; Park, Cheol-Hwan; Rotermund, Fabian; Kim, Dai-Sik

2015-09-01

Metal-graphene-metal hybrid structures allow angstrom-scale van der Waals gaps, across which electron tunneling occurs. We squeeze terahertz electromagnetic waves through these λ /10 000 000 gaps, accompanied by giant field enhancements. Unprecedented transmission reduction of 97% is achieved with the transient voltage across the gap saturating at 5 V. Electron tunneling facilitated by the transient electric field strongly modifies the gap index, starting a self-limiting process related to the barrier height. Our work enables greater interplay between classical optics and quantum tunneling, and provides optical indices to the van der Waals gaps.

Social Acceptance of Wind Energy: Managing and Evaluating Its Market Impacts (Presentation)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baring-Gould, I.

2012-06-01

As with any industrial-scale technology, wind power has impacts. As wind technology deployment becomes more widespread, a defined opposition will form as a result of fear of change and competing energy technologies. As the easy-to-deploy sites are developed, the costs of developing at sites with deployment barriers will increase, therefore increasing the total cost of power. This presentation provides an overview of wind development stakeholders and related stakeholder engagement questions, Energy Department activities that provide wind project deployment information, and the quantification of deployment barriers and costs in the continental United States.

Real-time ab initio KMC simulation of the self-assembly and sintering of bimetallic epitaxial nanoclusters: Au + Ag on Ag(100).

PubMed

Han, Yong; Liu, Da-Jiang; Evans, James W

2014-08-13

Far-from-equilibrium shape and structure evolution during formation and post-assembly sintering of bimetallic nanoclusters is extremely sensitive to the periphery diffusion and intermixing kinetics. Precise characterization of the many distinct local-environment-dependent diffusion barriers is achieved for epitaxial nanoclusters using density functional theory to assess interaction energies both with atoms at adsorption sites and at transition states. Kinetic Monte Carlo simulation incorporating these barriers then captures structure evolution on the appropriate time scale for two-dimensional core-ring and intermixed Au-Ag nanoclusters on Ag(100).

Real-Time Ab Initio KMC Simulation of the Self-Assembly and Sintering of Bimetallic Epitaxial Nanoclusters: Au + Ag on Ag(100)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Han, Yong; Liu, Da-Jiang; Evans, James W

2014-08-13

Far-from-equilibrium shape and structure evolution during formation and post-assembly sintering of bimetallic nanoclusters is extremely sensitive to the periphery diffusion and intermixing kinetics. Precise characterization of the many distinct local-environment-dependent diffusion barriers is achieved for epitaxial nanoclusters using density functional theory to assess interaction energies both with atoms at adsorption sites and at transition states. Kinetic Monte Carlo simulation incorporating these barriers then captures structure evolution on the appropriate time scale for two-dimensional core-ring and intermixed Au-Ag nanoclusters on Ag(100).

Review of Interconnection Practices and Costs in the Western States

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bird, Lori A; Flores-Espino, Francisco; Volpi, Christina M

The objective of this report is to evaluate the nature of barriers to interconnecting distributed PV, assess costs of interconnection, and compare interconnection practices across various states in the Western Interconnection. The report addresses practices for interconnecting both residential and commercial-scale PV systems to the distribution system. This study is part of a larger, joint project between the Western Interstate Energy Board (WIEB) and the National Renewable Energy Laboratory (NREL), funded by the U.S. Department of Energy, to examine barriers to distributed PV in the 11 states wholly within the Western Interconnection.

Reaching the Unreachable: Novel Approaches to Telemedicine Screening of Underserved Populations for Vitreoretinal Disease.

PubMed

Murchison, Ann P; Haller, Julia A; Mayro, Eileen; Hark, Lisa; Gower, Emily; Huisingh, Carrie; Rhodes, Lindsay; Friedman, David S; Lee, David J; Lam, Byron L

2017-07-01

Telemedicine involves electronic communication between a physician in one location and a patient in another location to provide remote medical care. Ophthalmologists are increasingly employing telemedicine, particularly in retinal disease screening and monitoring. Telemedicine has been utilized to decrease barriers to care and yield greater patient satisfaction and lower costs, while maintaining high sensitivity and specificity. This review discusses common patient barriers to eye care, innovative approaches to retinal disease screening and monitoring using telemedicine, and eye care policy initiatives needed to enact large-scale telemedicine eye disease screening programs.

Electromagnetic Saturation of Angstrom-Sized Quantum Barriers at Terahertz Frequencies.

PubMed

Bahk, Young-Mi; Kang, Bong Joo; Kim, Yong Seung; Kim, Joon-Yeon; Kim, Won Tae; Kim, Tae Yun; Kang, Taehee; Rhie, Jiyeah; Han, Sanghoon; Park, Cheol-Hwan; Rotermund, Fabian; Kim, Dai-Sik

2015-09-18

Metal-graphene-metal hybrid structures allow angstrom-scale van der Waals gaps, across which electron tunneling occurs. We squeeze terahertz electromagnetic waves through these λ/10 000 000 gaps, accompanied by giant field enhancements. Unprecedented transmission reduction of 97% is achieved with the transient voltage across the gap saturating at 5 V. Electron tunneling facilitated by the transient electric field strongly modifies the gap index, starting a self-limiting process related to the barrier height. Our work enables greater interplay between classical optics and quantum tunneling, and provides optical indices to the van der Waals gaps.

Use of historical and geospatial data to guide the restoration of a Lake Erie coastal marsh

USGS Publications Warehouse

Kowalski, Kurt P.; Wilcox, Douglas A.

1999-01-01

Historical and geospatial data were used to identify the relationships between water levels, wetland vegetation, littoral drift of sediments, and the condition of a protective barrier beach at Metzger Marsh, a coastal wetland in western Lake Erie, to enhance and guide a joint federal and state wetland restoration project. Eleven sets of large-scale aerial photographs dating from 1940 through 1994 were interpreted to delineate major vegetation types and boundaries of the barrier beach. A geographic information system (GIS) was then used to digitize the data and calculate the vegetated area and length of barrier beach. Supplemented by paleoecological and sedimentological analyses, aerial photographic interpretation revealed that Metzger Marsh was once a drowned-river-mouth wetland dominated by sedges and protected by a sand barrier beach. Extremely high water levels, storm events, and reduction of sediments in the littoral drift contributed to the complete destruction of the barrier beach in 1973 and prevented its recovery. The extent of wetland vegetation, correlated to water levels and condition of the barrier beach, decreased from a high of 108 ha in 1940 to a low of 33 ha in 1994. The lack of an adequate sediment supply and low probability of a period of extremely low lake levels in the near future made natural reestablishment of the barrier beach and wetland vegetation unlikely. Therefore, the federal and state managers chose to construct a dike to replace the protective barrier beach. Recommendations stemming from this historical analysis, however, resulted in the incorporation of a water-control structure in the dike that will retain a hydrologic connection between wetland and lake. Management of the wetland will seek to mimic processes natural to the wetland type identified by this analysis.

"Barriers to Cognitive Behavioral Therapy Homework Completion Scale- Depression Version": Development and Psychometric Evaluation.

PubMed

Callan, Judith A; Dunbar-Jacob, Jacqueline; Sereika, Susan M; Stone, Clement; Fasiczka, Amy; Jarrett, Robin B; Thase, Michael E

2012-01-01

We conducted a two-phase study to develop and evaluate the psychometric properties of an instrument to identify barriers to Cognitive Behavioral Therapy (CBT) homework completion in a depressed sample. In Phase I, we developed an item pool by interviewing 20 depressed patients and 20 CBT therapists. In Phase II, we created and administered a draft instrument to 56 people with depression. Exploratory Factor Analysis revealed a 2-factor oblique solution of "Patient Factors" and "Therapy/Task Factors." Internal consistency coefficients ranged from .80 to .95. Temporal stability was demonstrated through Pearson correlations of .72 (for the therapist/task subscale) to .95 (for the patient subscale) over periods of time that ranged from 2 days to 3 weeks. The patient subscale was able to satisfactorily classify patients (75 to 79 %) with low and high adherence at both sessions. Specificity was .66 at both time points. Sensitivity was .80 at sessions B and .77 at session C. There were no consistent predictors of assignment compliance when measured by the Assignment Compliance Rating Scale (Primakoff, Epstein, & Covi, 1986). The Rating Scale and subscale scores did, however, correlate significantly with assignment non-compliance (.32 to .46).

“Barriers to Cognitive Behavioral Therapy Homework Completion Scale- Depression Version”: Development and Psychometric Evaluation

PubMed Central

Callan, Judith A.; Dunbar-Jacob, Jacqueline; Sereika, Susan M.; Stone, Clement; Fasiczka, Amy; Jarrett, Robin B.; Thase, Michael E.

2013-01-01

We conducted a two-phase study to develop and evaluate the psychometric properties of an instrument to identify barriers to Cognitive Behavioral Therapy (CBT) homework completion in a depressed sample. In Phase I, we developed an item pool by interviewing 20 depressed patients and 20 CBT therapists. In Phase II, we created and administered a draft instrument to 56 people with depression. Exploratory Factor Analysis revealed a 2-factor oblique solution of “Patient Factors” and “Therapy/Task Factors.” Internal consistency coefficients ranged from .80 to .95. Temporal stability was demonstrated through Pearson correlations of .72 (for the therapist/task subscale) to .95 (for the patient subscale) over periods of time that ranged from 2 days to 3 weeks. The patient subscale was able to satisfactorily classify patients (75 to 79 %) with low and high adherence at both sessions. Specificity was .66 at both time points. Sensitivity was .80 at sessions B and .77 at session C. There were no consistent predictors of assignment compliance when measured by the Assignment Compliance Rating Scale (Primakoff, Epstein, & Covi, 1986). The Rating Scale and subscale scores did, however, correlate significantly with assignment non-compliance (.32 to .46). PMID:24049556

Surface roughening and scaling behavior of vacuum-deposited SnCl{sub 2}Pc organic thin films on different substrates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Obaidulla, Sk. Md.; Giri, P. K., E-mail: giri@iitg.ernet.in; Centre for Nanotechnology, Indian Institute of Technology Guwahati, Guwahati 781039

2015-11-30

The evolution of surface morphology and scaling behavior of tin (IV) phthalocyanine dichloride (SnCl{sub 2}Pc) thin films grown on Si(100) and glass substrates have been studied using atomic force microscopy (AFM) and height-height correlation function analysis. X-ray diffraction measurement confirms the crystalline nature of the SnCl{sub 2}Pc thin film on glass substrate, while no crystallographic ordering is present for the film grown on Si substrate. The growth exponent β is found to be much larger for the film on glass substrate (0.48 ± 0.07) as compared to that on Si substrate (0.21 ± 0.08), which may be due to the high step-edge barrier, so-calledmore » Ehrlich-Schwöbel barrier, resulting in the upward dominant growth on glass substrate. From the 2D fast Fourier transform of AFM images and derived scaling exponents, we conclude that the surface evolution follows a mound like growth. These results imply the superiority of glass substrate over the Si substrate for the growth of device quality SnCl{sub 2}Pc thin film.« less

Effect of film multi-scale structure on the water vapor permeability in hydroxypropyl starch (HPS)/Na-MMT nanocomposites.

PubMed

Liu, Siyuan; Cai, Panfu; Li, Xiaoxi; Chen, Ling; Li, Lin; Li, Bing

2016-12-10

To improve the water vapor resistance of starch-based films, Na-MMT (Na-montmorillonite) as nanofillers were fabricated into hydroxypropyl starch and the multi-scale structural changes (including intermolecular interaction, short-range conformation, long-range ordered structure and the aggregated structure of the film) were revealed. The elongation of the water vapor molecule pathway by tortuous path is generally recognized as the main reason for the improvement of water resistance. However this study observed the lowest water vapor permeability (WVP) was at the 3% Na-MMT/hydroxypropyl starch (HPS) ratio instead of 5% even nanofillers were partially exfoliated at both ratio. Except for the "tortuous path" caused by nanofillers, this observation proposed that the short-range conformation of HPS chains, long-range ordered structure and the aggregated structure likely influenced the water barrier property. The relationship between WVP and multi-scale structure of the film was investigated. The results suggested that a good balance of short-range conformationin the amorphous region, long-range ordered structure and the aggregated structure of the film was required for the improvement of water vapor barrier property. Copyright © 2016 Elsevier Ltd. All rights reserved.

Avoiding Implementation Failure in Catchment Landscapes: A Case Study in Governance of the Great Barrier Reef.

PubMed

Dale, Allan P; Vella, Karen; Gooch, Margaret; Potts, Ruth; Pressey, Robert L; Brodie, Jon; Eberhard, Rachel

2017-10-04

Water quality outcomes affecting Australia's Great Barrier Reef (GBR) are governed by multi-level and multi-party decision-making that influences forested and agricultural landscapes. With international concern about the GBR's declining ecological health, this paper identifies and focuses on implementation failure (primarily at catchment scale) as a systemic risk within the overall GBR governance system. There has been limited integrated analysis of the full suite of governance subdomains that often envelop defined policies, programs and delivery activities that influence water quality in the GBR. We consider how the implementation of separate purpose-specific policies and programs at catchment scale operate against well-known, robust design concepts for integrated catchment governance. We find design concerns within ten important governance subdomains that operate within GBR catchments. At a whole-of-GBR scale, we find a weak policy focus on strengthening these delivery-oriented subdomains and on effort integration across these subdomains within catchments. These governance problems when combined may contribute to failure in the implementation of major national, state and local government policies focused on improving water quality in the GBR, a lesson relevant to landscapes globally.

Reliability and validity of Champion's Health Belief Model Scale for breast cancer screening among Malaysian women.

PubMed

Parsa, P; Kandiah, M; Mohd Nasir, M T; Hejar, A R; Nor Afiah, M Z

2008-11-01

Breast cancer is the leading cause of cancer deaths in Malaysian women, and the use of breast self-examination (BSE), clinical breast examination (CBE) and mammography remain low in Malaysia. Therefore, there is a need to develop a valid and reliable tool to measure the beliefs that influence breast cancer screening practices. The Champion's Health Belief Model Scale (CHBMS) is a valid and reliable tool to measure beliefs about breast cancer and screening methods in the Western culture. The purpose of this study was to translate the use of CHBMS into the Malaysian context and validate the scale among Malaysian women. A random sample of 425 women teachers was taken from 24 secondary schools in Selangor state, Malaysia. The CHBMS was translated into the Malay language, validated by an expert's panel, back translated, and pretested. Analyses included descriptive statistics of all the study variables, reliability estimates, and construct validity using factor analysis. The mean age of the respondents was 37.2 (standard deviation 7.1) years. Factor analysis yielded ten factors for BSE with eigenvalue greater than 1 (four factors more than the original): confidence 1 (ability to differentiate normal and abnormal changes in the breasts), barriers to BSE, susceptibility for breast cancer, benefits of BSE, health motivation 1 (general health), seriousness 1 (fear of breast cancer), confidence 2 (ability to detect size of lumps), seriousness 2 (fear of long-term effects of breast cancer), health motivation 2 (preventive health practice), and confidence 3 (ability to perform BSE correctly). For CBE and mammography scales, seven factors each were identified. Factors for CBE scale include susceptibility, health motivation 1, benefits of CBE, seriousness 1, barriers of CBE, seriousness 2 and health motivation 2. For mammography the scale includes benefits of mammography, susceptibility, health motivation 1, seriousness 1, barriers to mammography seriousness 2 and health motivation 2. Cronbach's alpha reliability coefficients ranged from 0.774 to 0.939 for the subscales. The translated version of the CHBMS was found to be a valid and reliable tool for use with Malaysian women. It can be used easily to evaluate the health beliefs about breast cancer, BSE, CBE and mammography and for planning interventions. For greater applicability, it is recommended that this tool be tested among ethnically diverse populations.

Removing Full-scale Testing Barriers: Energetic Material Detonation Characterization at the Laboratory Scale

DTIC Science & Technology

2012-03-01

3708Unclassified Unclassified Unclassified ii Contents List of Figures iv List of Tables v Acknowledgments vi 1. Introduction 1 2. Theory/ Methodology ...Theory/ Methodology A shock wave is fully defined through knowledge of five state variables: shock pressure P , shock velocity U , particle velocity u...DIRECTOR US ARMY RESERACH LAB RDRL D 2800 POWDER MILL RD ADELPHI MD 20783-1197 21 NO. OF NO. OF COPIES ORGANIZATION COPIES ORGANIZATION 3 US ARMY RSRCH OFC

Observation time scale, free-energy landscapes, and molecular symmetry

PubMed Central

Wales, David J.; Salamon, Peter

2014-01-01

When structures that interconvert on a given time scale are lumped together, the corresponding free-energy surface becomes a function of the observation time. This view is equivalent to grouping structures that are connected by free-energy barriers below a certain threshold. We illustrate this time dependence for some benchmark systems, namely atomic clusters and alanine dipeptide, highlighting the connections to broken ergodicity, local equilibrium, and “feasible” symmetry operations of the molecular Hamiltonian. PMID:24374625

Under-the-barrier dynamics in laser-induced relativistic tunneling.

PubMed

Klaiber, Michael; Yakaboylu, Enderalp; Bauke, Heiko; Hatsagortsyan, Karen Z; Keitel, Christoph H

2013-04-12

The tunneling dynamics in relativistic strong-field ionization is investigated with the aim to develop an intuitive picture for the relativistic tunneling regime. We demonstrate that the tunneling picture applies also in the relativistic regime by introducing position dependent energy levels. The quantum dynamics in the classically forbidden region features two time scales, the typical time that characterizes the probability density's decay of the ionizing electron under the barrier (Keldysh time) and the time interval which the electron spends inside the barrier (Eisenbud-Wigner-Smith tunneling time). In the relativistic regime, an electron momentum shift as well as a spatial shift along the laser propagation direction arise during the under-the-barrier motion which are caused by the laser magnetic field induced Lorentz force. The momentum shift is proportional to the Keldysh time, while the wave-packet's spatial drift is proportional to the Eisenbud-Wigner-Smith time. The signature of the momentum shift is shown to be present in the ionization spectrum at the detector and, therefore, observable experimentally. In contrast, the signature of the Eisenbud-Wigner-Smith time delay disappears at far distances for pure quasistatic tunneling dynamics.

Release of cellular tension signals self-restorative ventral lamellipodia to heal barrier micro-wounds

PubMed Central

Martinelli, Roberta; Kamei, Masataka; Sage, Peter T.; Massol, Ramiro; Varghese, Laya; Sciuto, Tracey; Toporsian, Mourad; Dvorak, Ann M.; Kirchhausen, Tomas; Springer, Timothy A.

2013-01-01

Basic mechanisms by which cellular barriers sense and respond to integrity disruptions remain poorly understood. Despite its tenuous structure and constitutive exposure to disruptive strains, the vascular endothelium exhibits robust barrier function. We show that in response to micrometer-scale disruptions induced by transmigrating leukocytes, endothelial cells generate unique ventral lamellipodia that propagate via integrins toward and across these “micro-wounds” to close them. This novel actin remodeling activity progressively healed multiple micro-wounds in succession and changed direction during this process. Mechanical probe-induced micro-wounding of both endothelia and epithelia suggests that ventral lamellipodia formed as a response to force imbalance and specifically loss of isometric tension. Ventral lamellipodia were enriched in the Rac1 effectors cortactin, IQGAP, and p47Phox and exhibited localized production of hydrogen peroxide. Together with Apr2/3, these were functionally required for effective micro-wound healing. We propose that barrier disruptions are detected as local release of isometric tension/force unloading, which is directly coupled to reactive oxygen species–dependent self-restorative actin remodeling dynamics. PMID:23629967

Multiscale Investigations of the Early Stage Oxidation on Cu Surfaces

NASA Astrophysics Data System (ADS)

Zhu, Qing; Xiao, Penghao; Lian, Xin; Yang, Shen-Che; Henkelman, Grame; Saidi, Wissam; Yang, Judith; University of Pittsburgh Team; University of Texas at Austin Team

Previous in situ TEM experiments have shown that the oxidation of the three low index Cu surfaces (100), (110) and (111) exhibit different oxide nucleation rates, and the resulting oxides have 3-dimensional (3D) island shapes or 2D rafts under different conditions. In order to better understand these results, we have investigated the early stages of Cu oxidation using a multiscale computational approach that employs density functional theory (DFT), reactive force field (ReaxFF), and kinetic Mote Carlo (KMC). With DFT calculation, we have compared O2 dissociation barriers on Cu (100), (110) and (111) surfaces at high oxygen coverage to evaluate the kinetic barrier of sublayer oxidization. We found that O2 dissociation barriers on Cu(111) surface are all lower than those on (110) and (100) surfaces. This trend agrees with experimental observations that (111) surface is easier to oxidize. These DFT calculated energy barriers are then incorporated into KMC simulations. The large scale ReaxFF molecular dynamics and KMC simulations detail the oxidation dynamics of the different Cu surfaces, and show the formation of various oxide morphologies that are consistent with experimental observations.

Vertical field effect tunneling transistor based on graphene-ultrathin Si nanomembrane heterostructures

NASA Astrophysics Data System (ADS)

Das, Tanmoy; Jang, Houk; Bok Lee, Jae; Chu, Hyunwoo; Kim, Seong Dae; Ahn, Jong-Hyun

2015-12-01

Graphene-based heterostructured vertical transistors have attracted a great deal of research interest. Herein we propose a Si-based technology platform for creating graphene/ultrathin semiconductor/metal (GSM) junctions, which can be applied to large-scale and low-power electronics compatible with a variety of substrates. We fabricated graphene/Si nanomembrane (NM)/metal vertical heterostructures by using a dry transfer technique to transfer Si NMs onto chemical vapor deposition-grown graphene layers. The resulting van der Waals interfaces between graphene and p-Si NMs exhibited nearly ideal Schottky barrier behavior. Due to the low density of states of graphene, the graphene/Si NM Schottky barrier height can be modulated by modulating the band profile in the channel region, yielding well-defined current modulation. We obtained a maximum current on/off ratio (Ion/Ioff) of up to ˜103, with a current density of 102 A cm-2. We also observed significant dependence of Schottky barrier height Δφb on the thickness of the Si NMs. We confirmed that the transport in these devices is dominated by the effects of the graphene/Si NM Schottky barrier.

Influence of habitat discontinuity, geographical distance, and oceanography on fine-scale population genetic structure of copper rockfish (Sebastes caurinus).

PubMed

Johansson, M L; Banks, M A; Glunt, K D; Hassel-Finnegan, H M; Buonaccorsi, V P

2008-07-01

The copper rockfish is a benthic, nonmigratory, temperate rocky reef marine species with pelagic larvae and juveniles. A previous range-wide study of the population-genetic structure of copper rockfish revealed a pattern consistent with isolation-by-distance. This could arise from an intrinsically limited dispersal capability in the species or from regularly-spaced extrinsic barriers that restrict gene flow (offshore jets that advect larvae offshore and/or habitat patchiness). Tissue samples were collected along the West Coast of the contiguous USA between Neah Bay, WA and San Diego, CA, with dense sampling along Oregon. At the whole-coast scale (approximately 2200 km), significant population subdivision (F(ST) = 0.0042), and a significant correlation between genetic and geographical distance were observed based on 11 microsatellite DNA loci. Population divergence was also significant among Oregon collections (approximately 450 km, F(ST) = 0.001). Hierarchical amova identified a weak but significant 130-km habitat break as a possible barrier to gene flow within Oregon, across which we estimated that dispersal (N(e)m) is half that of the coast-wide average. However, individual-based Bayesian analyses failed to identify more than a single population along the Oregon coast. In addition, no correlation between pairwise population genetic and geographical distances was detected at this scale. The offshore jet at Cape Blanco was not a significant barrier to gene flow in this species. These findings are consistent with low larval dispersal distances calculated in previous studies on this species, support a mesoscale dispersal model, and highlight the importance of continuity of habitat and adult population size in maintaining gene flow.

Predictors of self-reported adherence to antihypertensive medicines: a multinational, cross-sectional survey.

PubMed

Morrison, Valerie L; Holmes, Emily A F; Parveen, Sahdia; Plumpton, Catrin O; Clyne, Wendy; De Geest, Sabina; Dobbels, Fabienne; Vrijens, Bernard; Kardas, Przemyslaw; Hughes, Dyfrig A

2015-03-01

Nonadherence to antihypertensive medicines limits their effectiveness, increases the risk of adverse health outcome, and is associated with significant health care costs. The multiple causes of nonadherence differ both within and between patients and are influenced by patients' care settings. The objective of this article was to identify determinants of patient nonadherence to antihypertensive medicines, drawing from psychosocial and economic models of behavior. Outpatients with hypertension from Austria, Belgium, England, Germany, Greece, Hungary, The Netherlands, Poland, and Wales were recruited to a cross-sectional online survey. Nonadherence to medicines was assessed using the Morisky Medication Adherence Scale (primary outcome) and the Medication Adherence Rating Scale. Associations with adherence and nonadherence were tested for demographic, clinical, and psychosocial factors. A total of 2595 patients completed the questionnaire. The percentage of patients classed as nonadherent ranged from 24% in The Netherlands to 70% in Hungary. Low age, low self-efficacy, and respondents' perceptions of their illness and cost-related barriers were associated with nonadherence measured on the Morisky Medication Adherence Scale across several countries. In multilevel, multivariate analysis, low self-efficacy (odds ratio = 0.73; 95% confidence interval 0.70-0.77) and a high number of perceived barriers to taking medicines (odds ratio = 1.70; 95% confidence interval 1.38-2.09) were the main significant determinants of nonadherence. Country differences explained 11% of the variance in nonadherence. Among the variables measured, patients' adherence to antihypertensive medicines is influenced primarily by their self-efficacy, illness beliefs, and perceived barriers. These should be targets for interventions for improving adherence, as should an appreciation of differences among the countries in which they are being delivered. Copyright © 2015 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

International Collaboration Activities on Engineered Barrier Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jove-Colon, Carlos F.

The Used Fuel Disposition Campaign (UFDC) within the DOE Fuel Cycle Technologies (FCT) program has been engaging in international collaborations between repository R&D programs for high-level waste (HLW) disposal to leverage on gathered knowledge and laboratory/field data of near- and far-field processes from experiments at underground research laboratories (URL). Heater test experiments at URLs provide a unique opportunity to mimetically study the thermal effects of heat-generating nuclear waste in subsurface repository environments. Various configurations of these experiments have been carried out at various URLs according to the disposal design concepts of the hosting country repository program. The FEBEX (Full-scale Engineeredmore » Barrier Experiment in Crystalline Host Rock) project is a large-scale heater test experiment originated by the Spanish radioactive waste management agency (Empresa Nacional de Residuos Radiactivos S.A. – ENRESA) at the Grimsel Test Site (GTS) URL in Switzerland. The project was subsequently managed by CIEMAT. FEBEX-DP is a concerted effort of various international partners working on the evaluation of sensor data and characterization of samples obtained during the course of this field test and subsequent dismantling. The main purpose of these field-scale experiments is to evaluate feasibility for creation of an engineered barrier system (EBS) with a horizontal configuration according to the Spanish concept of deep geological disposal of high-level radioactive waste in crystalline rock. Another key aspect of this project is to improve the knowledge of coupled processes such as thermal-hydro-mechanical (THM) and thermal-hydro-chemical (THC) operating in the near-field environment. The focus of these is on model development and validation of predictions through model implementation in computational tools to simulate coupled THM and THC processes.« less

A community empowerment approach to the HIV response among sex workers: effectiveness, challenges, and considerations for implementation and scale-up.

PubMed

Kerrigan, Deanna; Kennedy, Caitlin E; Morgan-Thomas, Ruth; Reza-Paul, Sushena; Mwangi, Peninah; Win, Kay Thi; McFall, Allison; Fonner, Virginia A; Butler, Jennifer

2015-01-10

A community empowerment-based response to HIV is a process by which sex workers take collective ownership of programmes to achieve the most effective HIV outcomes and address social and structural barriers to their overall health and human rights. Community empowerment has increasingly gained recognition as a key approach for addressing HIV in sex workers, with its focus on addressing the broad context within which the heightened risk for infection takes places in these individuals. However, large-scale implementation of community empowerment-based approaches has been scarce. We undertook a comprehensive review of community empowerment approaches for addressing HIV in sex workers. Within this effort, we did a systematic review and meta-analysis of the effectiveness of community empowerment in sex workers in low-income and middle-income countries. We found that community empowerment-based approaches to addressing HIV among sex workers were significantly associated with reductions in HIV and other sexually transmitted infections, and with increases in consistent condom use with all clients. Despite the promise of a community-empowerment approach, we identified formidable structural barriers to implementation and scale-up at various levels. These barriers include regressive international discourses and funding constraints; national laws criminalising sex work; and intersecting social stigmas, discrimination, and violence. The evidence base for community empowerment in sex workers needs to be strengthened and diversified, including its role in aiding access to, and uptake of, combination interventions for HIV prevention. Furthermore, social and political change are needed regarding the recognition of sex work as work, both globally and locally, to encourage increased support for community empowerment responses to HIV. Copyright © 2015 Elsevier Ltd. All rights reserved.

Computational Study of Chemical Reactivity Using Information-Theoretic Quantities from Density Functional Reactivity Theory for Electrophilic Aromatic Substitution Reactions.

PubMed

Wu, Wenjie; Wu, Zemin; Rong, Chunying; Lu, Tian; Huang, Ying; Liu, Shubin

2015-07-23

The electrophilic aromatic substitution for nitration, halogenation, sulfonation, and acylation is a vastly important category of chemical transformation. Its reactivity and regioselectivity is predominantly determined by nucleophilicity of carbon atoms on the aromatic ring, which in return is immensely influenced by the group that is attached to the aromatic ring a priori. In this work, taking advantage of recent developments in quantifying nucleophilicity (electrophilicity) with descriptors from the information-theoretic approach in density functional reactivity theory, we examine the reactivity properties of this reaction system from three perspectives. These include scaling patterns of information-theoretic quantities such as Shannon entropy, Fisher information, Ghosh-Berkowitz-Parr entropy and information gain at both molecular and atomic levels, quantitative predictions of the barrier height with both Hirshfeld charge and information gain, and energetic decomposition analyses of the barrier height for the reactions. To that end, we focused in this work on the identity reaction of the monosubstituted-benzene molecule reacting with hydrogen fluoride using boron trifluoride as the catalyst in the gas phase. We also considered 19 substituting groups, 9 of which are ortho/para directing and the other 9 meta directing, besides the case of R = -H. Similar scaling patterns for these information-theoretic quantities found for stable species elsewhere were disclosed for these reactions systems. We also unveiled novel scaling patterns for information gain at the atomic level. The barrier height of the reactions can reliably be predicted by using both the Hirshfeld charge and information gain at the regioselective carbon atom. The energy decomposition analysis ensued yields an unambiguous picture about the origin of the barrier height, where we showed that it is the electrostatic interaction that plays the dominant role, while the roles played by exchange-correlation and steric effects are minor but indispensable. Results obtained in this work should shed new light for better understanding of the factors governing the reactivity for this class of reactions and assisting ongoing efforts for the design of new and more efficient catalysts for such kind of transformations.

Complexities in barrier island response to sea level rise: Insights from numerical model experiments, North Carolina Outer Banks

USGS Publications Warehouse

Moore, Laura J.; List, Jeffrey H.; Williams, S. Jeffress; Stolper, David

2010-01-01

Using a morphological-behavior model to conduct sensitivity experiments, we investigate the sea level rise response of a complex coastal environment to changes in a variety of factors. Experiments reveal that substrate composition, followed in rank order by substrate slope, sea level rise rate, and sediment supply rate, are the most important factors in determining barrier island response to sea level rise. We find that geomorphic threshold crossing, defined as a change in state (e.g., from landward migrating to drowning) that is irreversible over decadal to millennial time scales, is most likely to occur in muddy coastal systems where the combination of substrate composition, depth-dependent limitations on shoreface response rates, and substrate erodibility may prevent sand from being liberated rapidly enough, or in sufficient quantity, to maintain a subaerial barrier. Analyses indicate that factors affecting sediment availability such as low substrate sand proportions and high sediment loss rates cause a barrier to migrate landward along a trajectory having a lower slope than average barrier island slope, thereby defining an “effective” barrier island slope. Other factors being equal, such barriers will tend to be smaller and associated with a more deeply incised shoreface, thereby requiring less migration per sea level rise increment to liberate sufficient sand to maintain subaerial exposure than larger, less incised barriers. As a result, the evolution of larger/less incised barriers is more likely to be limited by shoreface erosion rates or substrate erodibility making them more prone to disintegration related to increasing sea level rise rates than smaller/more incised barriers. Thus, the small/deeply incised North Carolina barriers are likely to persist in the near term (although their long-term fate is less certain because of the low substrate slopes that will soon be encountered). In aggregate, results point to the importance of system history (e.g., previous slopes, sediment budgets, etc.) in determining migration trajectories and therefore how a barrier island will respond to sea level rise. Although simple analytical calculations may predict barrier response in simplified coastal environments (e.g., constant slope, constant sea level rise rate, etc.), our model experiments demonstrate that morphological-behavior modeling is necessary to provide critical insights regarding changes that may occur in environments having complex geometries, especially when multiple parameters change simultaneously.

Pediatric Educational Needs Assessment for Urban and Rural Emergency Medical Technicians

PubMed Central

Fleischman, Ross J.; Yarris, Lalena M.; Curry, Merlin T.; Yuen, Stephanie C.; Breon, Alia R.; Meckler, Garth D.

2011-01-01

Objective To identify past experiences, present needs, barriers, and desired methods of training for urban and rural EMTs. Methods This 62-question pilot-tested written survey was administered at the 2008 Oregon EMS and 2009 EMS for Children conferences. Respondents were compared to registration lists and the state EMS database to assess for non-responder bias. Agencies more than 10 miles from a population of 40,000 were defined as rural. Results Two-hundred nineteen of 313 EMS personnel (70%) returned surveys. Respondents were 3% first responders, 27% EMT-basics, 20% intermediates, and 47% paramedics. Sixty-eight percent were rural and 32% urban. Sixty-eight percent reported fewer than 10% pediatric transports. Overall, respondents rated their comfort caring for pediatric patients as 3.1 on a 5 point likert scale (95%CI 3.1–3.2). Seventy-two percent reported a mean rating of less than “comfortable” (four on the scale) across 17 topics in pediatric care, which did not differ by certification level. Seven percent reported no pediatric training in the last two years and 76% desired more. The “quality of available trainings” was ranked as the most important barrier to training. 26% of rural versus 7% of urban EMS personnel ranked distance as the most significant barrier (p<0.01). Fifty-one percent identified highly realistic simulations as the method that helped them learn best. In the past two years, 19% percent had trained on a highly realistic pediatric simulator. One to three hours was the preferred duration for trainings. Conclusions Except for distance as a barrier, there were no significant differences between urban and rural responses. Both urban and rural providers desire resources, in particular highly realistic simulation, to address the infrequency of pediatric transports and limited training. PMID:22134229

Barriers to physicians' adoption of healthcare information technology: an empirical study on multiple hospitals.

PubMed

Lin, Chihung; Lin, I-Chun; Roan, Jinsheng

2012-06-01

Prior research on technology usage had largely overlooked the issue of user resistance or barriers to technology acceptance. Prior research on the Electronic Medical Records had largely focused on technical issues but rarely on managerial issues. Such oversight prevented a better understanding of users' resistance to new technologies and the antecedents of technology rejection. Incorporating the enablers and the inhibitors of technology usage intention, this study explores physicians' reactions towards the electronic medical record. The main focus is on the barriers, perceived threat and perceived inequity. 115 physicians from 6 hospitals participated in the questionnaire survey. Structural Equation Modeling was employed to verify the measurement scale and research hypotheses. According to the results, perceived threat shows a direct and negative effect on perceived usefulness and behavioral intentions, as well as an indirect effect on behavioral intentions via perceived usefulness. Perceived inequity reveals a direct and positive effect on perceived threat, and it also shows a direct and negative effect on perceived usefulness. Besides, perceived inequity reveals an indirect effect on behavioral intentions via perceived usefulness with perceived threat as the inhibitor. The research finding presents a better insight into physicians' rejection and the antecedents of such outcome. For the healthcare industry understanding the factors contributing to physicians' technology acceptance is important as to ensure a smooth implementation of any new technology. The results of this study can also provide change managers reference to a smooth IT introduction into an organization. In addition, our proposed measurement scale can be applied as a diagnostic tool for them to better understand the status quo within their organizations and users' reactions to technology acceptance. By doing so, barriers to physicians' acceptance can be identified earlier and more effectively before leading to technology rejection.

Testing the effect of the Himalayan mountains as a physical barrier to gene flow in Hippophae tibetana Schlect. (Elaeagnaceae)

PubMed Central

Qiong, La; Zhang, Wenju; Wang, Hao; Zeng, Liyan; Birks, H. John B.; Zhong, Yang

2017-01-01

Hippophae tibetana is a small, dioecious wind-pollinated shrub endemic to the Tibetan-Qinghai Plateau. It is one of the shrubs that occur at very high elevations (5250 m a.s.l.). The Himalayan mountains provides a significant geographical barrier to the Qinghai-Tibetan Plateau, dividing the Himalayan area into two regions with Nepal to the south and Tibet to the north. There is no information on how the Himalayan mountains influence gene flow and population differentiation of alpine plants. In this study, we analyzed eight nuclear microsatellite markers and cpDNA trnT-trnF regions to test the role of the Himalayan mountains as a barrier to gene flow between populations of H. tibetana. We also examined the fine-scale genetic structure within a population of H. tibetana on the north slope of Mount (Mt.) Everest. For microsatellite analyses, a total of 241 individuals were sampled from seven populations in our study area (4 from Nepal, 3 from Tibet), including 121 individuals that were spatially mapped within a 100 m × 100 m plot. To test for seed flow, the cpDNA trnT-trnF regions of 100 individuals from 6 populations (4 from Nepal, 2 from Tibet) were also sequenced. Significant genetic differentiation was detected between the two regions by both microsatellite and cpDNA data analyses. These two datasets agree about southern and northern population differentiation, indicating that the Himalayan mountains represent a barrier to H. tibetana limiting gene flow between these two areas. At a fine scale, spatial autocorrelation analysis suggests significant genetic structure within a distance of less than 45 m, which may be attributed mainly to vegetative reproduction and habitat fragmentation, as well as limited gene flow. PMID:28489850

Testing the effect of the Himalayan mountains as a physical barrier to gene flow in Hippophae tibetana Schlect. (Elaeagnaceae).

PubMed

Qiong, La; Zhang, Wenju; Wang, Hao; Zeng, Liyan; Birks, H John B; Zhong, Yang

2017-01-01

Hippophae tibetana is a small, dioecious wind-pollinated shrub endemic to the Tibetan-Qinghai Plateau. It is one of the shrubs that occur at very high elevations (5250 m a.s.l.). The Himalayan mountains provides a significant geographical barrier to the Qinghai-Tibetan Plateau, dividing the Himalayan area into two regions with Nepal to the south and Tibet to the north. There is no information on how the Himalayan mountains influence gene flow and population differentiation of alpine plants. In this study, we analyzed eight nuclear microsatellite markers and cpDNA trnT-trnF regions to test the role of the Himalayan mountains as a barrier to gene flow between populations of H. tibetana. We also examined the fine-scale genetic structure within a population of H. tibetana on the north slope of Mount (Mt.) Everest. For microsatellite analyses, a total of 241 individuals were sampled from seven populations in our study area (4 from Nepal, 3 from Tibet), including 121 individuals that were spatially mapped within a 100 m × 100 m plot. To test for seed flow, the cpDNA trnT-trnF regions of 100 individuals from 6 populations (4 from Nepal, 2 from Tibet) were also sequenced. Significant genetic differentiation was detected between the two regions by both microsatellite and cpDNA data analyses. These two datasets agree about southern and northern population differentiation, indicating that the Himalayan mountains represent a barrier to H. tibetana limiting gene flow between these two areas. At a fine scale, spatial autocorrelation analysis suggests significant genetic structure within a distance of less than 45 m, which may be attributed mainly to vegetative reproduction and habitat fragmentation, as well as limited gene flow.

Exploring the variation in implementation of a COPD disease management programme and its impact on health outcomes: a post hoc analysis of the RECODE cluster randomised trial.

PubMed

Boland, Melinde R S; Kruis, Annemarije L; Huygens, Simone A; Tsiachristas, Apostolos; Assendelft, Willem J J; Gussekloo, Jacobijn; Blom, Coert M G; Chavannes, Niels H; Rutten-van Mölken, Maureen P M H

2015-12-17

This study aims to (1) examine the variation in implementation of a 2-year chronic obstructive pulmonary disease (COPD) management programme called RECODE, (2) analyse the facilitators and barriers to implementation and (3) investigate the influence of this variation on health outcomes. Implementation variation among the 20 primary-care teams was measured directly using a self-developed scale and indirectly through the level of care integration as measured with the Patient Assessment of Chronic Illness Care (PACIC) and the Assessment of Chronic Illness Care (ACIC). Interviews were held to obtain detailed information regarding the facilitators and barriers to implementation. Multilevel models were used to investigate the association between variation in implementation and change in outcomes. The teams implemented, on average, eight of the 19 interventions, and the specific package of interventions varied widely. Important barriers and facilitators of implementation were (in)sufficient motivation of healthcare provider and patient, the high starting level of COPD care, the small size of the COPD population per team, the mild COPD population, practicalities of the information and communication technology (ICT) system, and hurdles in reimbursement. Level of implementation as measured with our own scale and the ACIC was not associated with health outcomes. A higher level of implementation measured with the PACIC was positively associated with improved self-management capabilities, but this association was not found for other outcomes. There was a wide variety in the implementation of RECODE, associated with barriers at individual, social, organisational and societal level. There was little association between extent of implementation and health outcomes.

Exploring the variation in implementation of a COPD disease management programme and its impact on health outcomes: a post hoc analysis of the RECODE cluster randomised trial

PubMed Central

Boland, Melinde R S; Kruis, Annemarije L; Huygens, Simone A; Tsiachristas, Apostolos; Assendelft, Willem J J; Gussekloo, Jacobijn; Blom, Coert M G; Chavannes, Niels H; Rutten-van Mölken, Maureen P M H

2015-01-01

This study aims to (1) examine the variation in implementation of a 2-year chronic obstructive pulmonary disease (COPD) management programme called RECODE, (2) analyse the facilitators and barriers to implementation and (3) investigate the influence of this variation on health outcomes. Implementation variation among the 20 primary-care teams was measured directly using a self-developed scale and indirectly through the level of care integration as measured with the Patient Assessment of Chronic Illness Care (PACIC) and the Assessment of Chronic Illness Care (ACIC). Interviews were held to obtain detailed information regarding the facilitators and barriers to implementation. Multilevel models were used to investigate the association between variation in implementation and change in outcomes. The teams implemented, on average, eight of the 19 interventions, and the specific package of interventions varied widely. Important barriers and facilitators of implementation were (in)sufficient motivation of healthcare provider and patient, the high starting level of COPD care, the small size of the COPD population per team, the mild COPD population, practicalities of the information and communication technology (ICT) system, and hurdles in reimbursement. Level of implementation as measured with our own scale and the ACIC was not associated with health outcomes. A higher level of implementation measured with the PACIC was positively associated with improved self-management capabilities, but this association was not found for other outcomes. There was a wide variety in the implementation of RECODE, associated with barriers at individual, social, organisational and societal level. There was little association between extent of implementation and health outcomes. PMID:26677770

Relationship between performance barriers and pharmacist competency towards the implementation of an expanded public health pharmacy role.

PubMed

Mathialagan, Amuthaganesh; Nagalinggam, Preesha; Mathialagan, Saravanabavan; Kirby, Brian P

2015-10-01

The objective of this study was to examine the relationship between performance barriers and competency, and implementation of an expanded public health role for community pharmacists. A validated questionnaire was utilised for this study whereby three variables of the study (performance barriers, competency and public health role) were measured using a 5-point Likert scale. Three hundred questionnaires were distributed to target respondents of registered community pharmacies in five states (Johor, Negeri Sembilan, Selangor, Perak and Penang) in Malaysia. The data were analysed utilising the principles of structural equation modelling. There were 191 completed and usable responses received, which represented a 66.7% response rate. This study showed perceived competency had a direct relationship with delivering a general public health role. A perceived lack of competency was shown to be a barrier to fulfilling a public health role. However, other factors, such as design of premises, IT infrastructure and pay, were not viewed as barriers to carrying out a public health role. Perceived competency is an obstacle for community pharmacists to undertake a public health role in Malaysia. Adequate training programmes in pharmaceutical public health have to be put in place to address this concern and this should therefore be a priority. © 2015 Royal Pharmaceutical Society.

Seismic evidence of glacial-age river incision into the Tahaa barrier reef, French Polynesia

USGS Publications Warehouse

Toomey, Michael; Woodruff, Jonathan D.; Ashton, Andrew D.; Perron, J. Taylor

2016-01-01

Rivers have long been recognized for their ability to shape reef-bound volcanic islands. On the time-scale of glacial–interglacial sea-level cycles, fluvial incision of exposed barrier reef lagoons may compete with constructional coral growth to shape the coastal geomorphology of ocean islands. However, overprinting of Pleistocene landscapes by Holocene erosion or sedimentation has largely obscured the role lowstand river incision may have played in developing the deep lagoons typical of modern barrier reefs. Here we use high-resolution seismic imagery and core stratigraphy to examine how erosion and/or deposition by upland drainage networks has shaped coastal morphology on Tahaa, a barrier reef-bound island located along the Society Islands hotspot chain in French Polynesia. At Tahaa, we find that many channels, incised into the lagoon floor during Pleistocene sea-level lowstands, are located near the mouths of upstream terrestrial drainages. Steeper antecedent topography appears to have enhanced lowstand fluvial erosion along Tahaa's southwestern coast and maintained a deep pass. During highstands, upland drainages appear to contribute little sediment to refilling accommodation space in the lagoon. Rather, the flushing of fine carbonate sediment out of incised fluvial channels by storms and currents appears to have limited lagoonal infilling and further reinforced development of deep barrier reef lagoons during periods of highstand submersion.

Masculinity and race-related factors as barriers to health help-seeking barriers among African-American men

PubMed Central

Powell, Wizdom; Adams, Leslie B.; Cole-Lewis, Yasmin; Agyemang, Amma; Upton, Rachel D.

2016-01-01

Men’s tendency to delay health help-seeking is largely attributed to masculinity, but findings scarcely focus on African-American men who face additional race-related, help-seeking barriers. Building principally on reactance theory, we test a hypothesized model situating racial discrimination, masculinity norms salience, everyday racism (ERD), racial identity (RI), sense of control (SOC) and depressive symptomatology as key barriers to African-American men’s health help-seeking. 458 African-American men were recruited primarily from U.S. barbershops in the Western and Southern regions. The primary outcome was Barriers to Help-Seeking Scale (BHSS) scores. The hypothesized model was investigated with confirmatory factor and path analysis with tests for measurement invariance. Our model fit was excellent χ2(4,N = 457) = 3.84, p > .05; CFI = .99; TLI = 1.00; RMSEA = .00, and 90% CI [.00, .07] and operated equivalently across different age, income, and education strata. Frequent ERD and higher MNS contributed to higher BHHS scores. The relationship between ERD exposure and BHHS scores was partially mediated by diminished SOC and greater depressive symptomatology. Interventions aimed at addressing African-American men’s health help-seeking should not only address masculinity norms, but also threats to sense of control, and negative psychological sequelae induced by everyday racism. PMID:27337619

Large-scale, thick, self-assembled, nacre-mimetic brick-walls as fire barrier coatings on textiles

NASA Astrophysics Data System (ADS)

Das, Paramita; Thomas, Helga; Moeller, Martin; Walther, Andreas

2017-01-01

Highly loaded polymer/clay nanocomposites with layered structures are emerging as robust fire retardant surface coatings. However, time-intensive sequential deposition processes, e.g. layer-by-layer strategies, hinders obtaining large coating thicknesses and complicates an implementation into existing technologies. Here, we demonstrate a single-step, water-borne approach to prepare thick, self-assembling, hybrid fire barrier coatings of sodium carboxymethyl cellulose (CMC)/montmorillonite (MTM) with well-defined, bioinspired brick-wall nanostructure, and showcase their application on textile. The coating thickness on the textile is tailored using different concentrations of CMC/MTM (1-5 wt%) in the coating bath. While lower concentrations impart conformal coatings of fibers, thicker continuous coatings are obtained on the textile surface from highest concentration. Comprehensive fire barrier and fire retardancy tests elucidate the increasing fire barrier and retardancy properties with increasing coating thickness. The materials are free of halogen and heavy metal atoms, and are sourced from sustainable and partly even renewable building blocks. We further introduce an amphiphobic surface modification on the coating to impart oil and water repellency, as well as self-cleaning features. Hence, our study presents a generic, environmentally friendly, scalable, and one-pot coating approach that can be introduced into existing technologies to prepare bioinspired, thick, fire barrier nanocomposite coatings on diverse surfaces.

Liquid spray experiments

NASA Astrophysics Data System (ADS)

Lapham, Gary; McHugh, John

When waves on the ocean surface interact with a solid object, the result is often a complex pattern of spray. The solid object may be a coastal barrier such as a breakwater, or a ship or drilling rig. Another spray-related case is the presence of large industrial tanks of liquid, and often dangerous liquids, that exist around the world. Tens of thousands of such tanks are rapidly becoming obsolete. Recent experience has shown that when such tanks burst, the resulting spray may shoot several hundreds of meters from the tank. These tanks often have a wall or dam (barrier) surrounding them in an attempt to contain any leakage, catastrophic or otherwise. When the tank bursts it is akin to the dam-break problem. A wall of water rushes forth and impinges on the barrier creating spray. Previous experiments (McHugh and Watt, 1998) considered the related configuration of a solitary wave impinging on a vertical wall. The present experiments more closely model the bursting tank case, and treat the effect of the distance between the tank and barrier. Results show that there is a sweet spot where height and horizontal distance of spray droplets are maximized. This ideal distance between tank and barrier is constant when scaled by the initial tank depth.

Transition path time distributions

NASA Astrophysics Data System (ADS)

Laleman, M.; Carlon, E.; Orland, H.

2017-12-01

Biomolecular folding, at least in simple systems, can be described as a two state transition in a free energy landscape with two deep wells separated by a high barrier. Transition paths are the short part of the trajectories that cross the barrier. Average transition path times and, recently, their full probability distribution have been measured for several biomolecular systems, e.g., in the folding of nucleic acids or proteins. Motivated by these experiments, we have calculated the full transition path time distribution for a single stochastic particle crossing a parabolic barrier, including inertial terms which were neglected in previous studies. These terms influence the short time scale dynamics of a stochastic system and can be of experimental relevance in view of the short duration of transition paths. We derive the full transition path time distribution as well as the average transition path times and discuss the similarities and differences with the high friction limit.

Enhanced bioremediation of BTEX using immobilized nutrients: Field demonstration and monitoring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Borden, R.C.; Goin, R.T.; Kao, C.M.

1996-12-01

A permeable barrier system was developed for controlling the migration of dissolved contaminant plumes in ground water. The barrier system consisted of a line of closely spaced wells installed perpendicular to the contaminant plume. Each well contained concrete briquets that released oxygen and nitrate at a controlled rate, enhancing the aerobic biodegradation of dissolved hydrocarbons in the downgradient aquifer. A full scale permeable barrier system was constructed at a gasoline-spill site near Leland, NC. Initially, increased dissolved oxygen and decreased benzene, toluene, ethylbenzene, and xylene isomer (BTEX) concentrations in the downgradient aquifer indicated that oxygen released from the remediation wellsmore » was enhancing biodegradation. Field tracer tests and soil analyses performed at the conclusion of the project indicated that the aquifer in the vicinity of the remediation wells was being clogged by precipitation from iron minerals.« less

Engaging underserved audiences in informal science education through community-based partnerships

NASA Astrophysics Data System (ADS)

Bouzo, Suzanne

This thesis explores the impact of the Science Education and Engagement of Denver (SEED) Partnership on three of its participant families. The partnership, consisting of large informal science organizations, as well as small community-based organizations, created its programming based on prior research identifying barriers to minority participation in informal science education programs. SEED aims to engage youth and families of emerging populations in science and nature. Three families were examined as a case study to have an in depth investigation about their involvement in the programs sponsored by the partnership. Findings suggest a positive impact on participant feelings and engagement in science and nature. Future recommendations are made for furthering programming as well as conducting a larger scale, more comprehensive program evaluation. This research addresses prior studies that have identified several barriers toward participation of underserved audiences in informal science education programs and how the SEED partnership has addressed specific identified barriers.

Ideal MHD Stability Prediction and Required Power for EAST Advanced Scenario

NASA Astrophysics Data System (ADS)

Chen, Junjie; Li, Guoqiang; Qian, Jinping; Liu, Zixi

2012-11-01

The Experimental Advanced Superconducting Tokamak (EAST) is the first fully superconducting tokamak with a D-shaped cross-sectional plasma presently in operation. The ideal magnetohydrodynamic (MHD) stability and required power for the EAST advanced tokamak (AT) scenario with negative central shear and double transport barrier (DTB) are investigated. With the equilibrium code TOQ and stability code GATO, the ideal MHD stability is analyzed. It is shown that a moderate ratio of edge transport barriers' (ETB) height to internal transport barriers' (ITBs) height is beneficial to ideal MHD stability. The normalized beta βN limit is about 2.20 (without wall) and 3.70 (with ideal wall). With the scaling law of energy confinement time, the required heating power for EAST AT scenario is calculated. The total heating power Pt increases as the toroidal magnetic field BT or the normalized beta βN is increased.

Intrinsic rotation, hysteresis and back transition in reversed shear internal transport barriers

NASA Astrophysics Data System (ADS)

Kim, S. S.; Jhang, Hogun; Diamond, P. H.; Terzolo, L.; Yi, S.; Hahm, T. S.

2011-07-01

A study of intrinsic rotation and hysteresis in ion thermal internal transport barrier (ITB) is presented. Global flux-driven gyrofluid simulations are performed. It is found that significant co-current intrinsic rotation (0.1 <~ Mth <~ 0.2, where Mth is the thermal Mach number) can be produced in ITB plasmas. Exploration of the relationship between the intrinsic rotation and the ITB temperature gradient leads to a novel scaling of intrinsic rotation in ITB plasmas. Long time power ramp simulations with self-consistently evolving profiles clearly demonstrate the existence of hysteresis in reversed shear ITBs. It is shown that intrinsic rotation plays an important role in ITB dynamics and is responsible for determining unique properties of ITB hysteresis. A negative feedback mechanism based on destruction of E × B shear prevails in barrier back transition, triggered by an outward momentum transport event during the power ramp down.

Risk Mitigation in Preventing Adventitious Agent Contamination of Mammalian Cell Cultures.

PubMed

Shiratori, Masaru; Kiss, Robert

2017-11-14

Industrial-scale mammalian cell culture processes have been contaminated by viruses during the culturing phase. Although the historical frequency of such events has been quite low, the impact of contamination can be significant for the manufacturing company and for the supply of the product to patients. This chapter discusses sources of adventitious agent contamination risk in a cell culture process, provides a semiquantitative assessment of such risks, and describes potential process barriers that can be used to reduce contamination risk. High-temperature, short-time (HTST) heat treatment is recommended as the process barrier of choice, when compatible with the process. A case study assessing the compatibility of HTST heat treatment with a cell culture medium is presented, and lessons learned are shared from our experiences over many years of developing and implementing virus barriers in mammalian cell culture processes. Graphical Abstract.

Impact tests of crash energy management passenger rail cars: analysis and structural measurements

DOT National Transportation Integrated Search

2004-11-13

Two full-scale impact tests were conducted to measure the : crashworthiness performance of Crash Energy Management : (CEM) passenger rail cars. On December 3, 2003 a single car : impacted a fixed barrier at approximately 35 mph and on : February 26, ...

ZERO-VALENT IRON PRB APPLICATION EXPANDS TO ARSENIC REMOVAL

EPA Science Inventory

The U.S. EPA Office of Research and Development’s National Risk Management Research Laboratory (NRMRL) and Region 8 have begun evaluating performance of a pilot-scale permeable reactive barrier (PRB) to treat arsenic-contaminated ground water at the ASARCO Superfund near Helena, ...

Homeostasis of the gut barrier and potential biomarkers.

PubMed

Wells, Jerry M; Brummer, Robert J; Derrien, Muriel; MacDonald, Thomas T; Troost, Freddy; Cani, Patrice D; Theodorou, Vassilia; Dekker, Jan; Méheust, Agnes; de Vos, Willem M; Mercenier, Annick; Nauta, Arjen; Garcia-Rodenas, Clara L

2017-03-01

The gut barrier plays a crucial role by spatially compartmentalizing bacteria to the lumen through the production of secreted mucus and is fortified by the production of secretory IgA (sIgA) and antimicrobial peptides and proteins. With the exception of sIgA, expression of these protective barrier factors is largely controlled by innate immune recognition of microbial molecular ligands. Several specialized adaptations and checkpoints are operating in the mucosa to scale the immune response according to the threat and prevent overreaction to the trillions of symbionts inhabiting the human intestine. A healthy microbiota plays a key role influencing epithelial barrier functions through the production of short-chain fatty acids (SCFAs) and interactions with innate pattern recognition receptors in the mucosa, driving the steady-state expression of mucus and antimicrobial factors. However, perturbation of gut barrier homeostasis can lead to increased inflammatory signaling, increased epithelial permeability, and dysbiosis of the microbiota, which are recognized to play a role in the pathophysiology of a variety of gastrointestinal disorders. Additionally, gut-brain signaling may be affected by prolonged mucosal immune activation, leading to increased afferent sensory signaling and abdominal symptoms. In turn, neuronal mechanisms can affect the intestinal barrier partly by activation of the hypothalamus-pituitary-adrenal axis and both mast cell-dependent and mast cell-independent mechanisms. The modulation of gut barrier function through nutritional interventions, including strategies to manipulate the microbiota, is considered a relevant target for novel therapeutic and preventive treatments against a range of diseases. Several biomarkers have been used to measure gut permeability and loss of barrier integrity in intestinal diseases, but there remains a need to explore their use in assessing the effect of nutritional factors on gut barrier function. Future studies should aim to establish normal ranges of available biomarkers and their predictive value for gut health in human cohorts. Copyright © 2017 the American Physiological Society.

Factors Affecting Attendance at an Adapted Cardiac Rehabilitation Exercise Program for Individuals with Mobility Deficits Poststroke.

PubMed

Marzolini, Susan; Balitsky, Amaris; Jagroop, David; Corbett, Dale; Brooks, Dina; Grace, Sherry L; Lawrence, Danielle; Oh, Paul I

2016-01-01

The aim of this study was to determine the factors affecting attendance at an adapted cardiac rehabilitation program for individuals poststroke. A convenience sample of ambulatory patients with hemiparetic gait rated 20 potential barriers to attendance on a 5-point Likert scale upon completion of a 6-month program of 24 prescheduled weekly sessions. Sociodemographic characteristics, depressive symptoms, cardiovascular fitness, and comorbidities were collected by questionnaire or medical chart. Sixty-one patients attended 77.3 ± 12% of the classes. The longer the elapsed time from stroke, the lower the attendance rate (r = -.34, P = .02). The 4 greatest barriers influencing attendance were severe weather, transportation problems, health problems, and traveling distance. Health problems included hospital readmissions (n = 6), influenza/colds (n = 6), diabetes and cardiac complications (n = 4), and musculoskeletal issues (n = 2). Of the top 4 barriers, people with lower compared to higher income had greater transportation issues (P = .004). Greater motor deficits of the stroke-affected leg were associated with greater barriers related to health issues (r = .7, P = .001). The only sociodemographic factor associated with a higher total mean barrier score was non-English as the primary language spoken at home (P = .002); this factor was specifically related to the barriers of cost (P = .007), family responsibilities (P = .018), and lack of social support (P = .001). No other associations were observed. Barriers to attendance were predominantly related to logistic/transportation and health issues. People who were more disadvantaged socioeconomically (language, finances), and physically (stroke-related deficits) were more affected by these barriers. Strategies to reduce these barriers, including timely referral to exercise programs, need to be investigated. Copyright © 2015 National Stroke Association. Published by Elsevier Inc. All rights reserved.

Homeostasis of the gut barrier and potential biomarkers

PubMed Central

Brummer, Robert J.; Derrien, Muriel; MacDonald, Thomas T.; Troost, Freddy; Cani, Patrice D.; Theodorou, Vassilia; Dekker, Jan; Méheust, Agnes; de Vos, Willem M.; Mercenier, Annick; Nauta, Arjen; Garcia-Rodenas, Clara L.

2017-01-01

The gut barrier plays a crucial role by spatially compartmentalizing bacteria to the lumen through the production of secreted mucus and is fortified by the production of secretory IgA (sIgA) and antimicrobial peptides and proteins. With the exception of sIgA, expression of these protective barrier factors is largely controlled by innate immune recognition of microbial molecular ligands. Several specialized adaptations and checkpoints are operating in the mucosa to scale the immune response according to the threat and prevent overreaction to the trillions of symbionts inhabiting the human intestine. A healthy microbiota plays a key role influencing epithelial barrier functions through the production of short-chain fatty acids (SCFAs) and interactions with innate pattern recognition receptors in the mucosa, driving the steady-state expression of mucus and antimicrobial factors. However, perturbation of gut barrier homeostasis can lead to increased inflammatory signaling, increased epithelial permeability, and dysbiosis of the microbiota, which are recognized to play a role in the pathophysiology of a variety of gastrointestinal disorders. Additionally, gut-brain signaling may be affected by prolonged mucosal immune activation, leading to increased afferent sensory signaling and abdominal symptoms. In turn, neuronal mechanisms can affect the intestinal barrier partly by activation of the hypothalamus-pituitary-adrenal axis and both mast cell-dependent and mast cell-independent mechanisms. The modulation of gut barrier function through nutritional interventions, including strategies to manipulate the microbiota, is considered a relevant target for novel therapeutic and preventive treatments against a range of diseases. Several biomarkers have been used to measure gut permeability and loss of barrier integrity in intestinal diseases, but there remains a need to explore their use in assessing the effect of nutritional factors on gut barrier function. Future studies should aim to establish normal ranges of available biomarkers and their predictive value for gut health in human cohorts. PMID:27908847

Fine-scale population structure and the era of next-generation sequencing.

PubMed

Henn, Brenna M; Gravel, Simon; Moreno-Estrada, Andres; Acevedo-Acevedo, Suehelay; Bustamante, Carlos D

2010-10-15

Fine-scale population structure characterizes most continents and is especially pronounced in non-cosmopolitan populations. Roughly half of the world's population remains non-cosmopolitan and even populations within cities often assort along ethnic and linguistic categories. Barriers to random mating can be ecologically extreme, such as the Sahara Desert, or cultural, such as the Indian caste system. In either case, subpopulations accumulate genetic differences if the barrier is maintained over multiple generations. Genome-wide polymorphism data, initially with only a few hundred autosomal microsatellites, have clearly established differences in allele frequency not only among continental regions, but also within continents and within countries. We review recent evidence from the analysis of genome-wide polymorphism data for genetic boundaries delineating human population structure and the main demographic and genomic processes shaping variation, and discuss the implications of population structure for the distribution and discovery of disease-causing genetic variants, in the light of the imminent availability of sequencing data for a multitude of diverse human genomes.

Scaling and Graphical Transport-Map Analysis of Ambipolar Schottky-Barrier Thin-Film Transistors Based on a Parallel Array of Si Nanowires.

PubMed

Jeon, Dae-Young; Pregl, Sebastian; Park, So Jeong; Baraban, Larysa; Cuniberti, Gianaurelio; Mikolajick, Thomas; Weber, Walter M

2015-07-08

Si nanowire (Si-NW) based thin-film transistors (TFTs) have been considered as a promising candidate for next-generation flexible and wearable electronics as well as sensor applications with high performance. Here, we have fabricated ambipolar Schottky-barrier (SB) TFTs consisting of a parallel array of Si-NWs and performed an in-depth study related to their electrical performance and operation mechanism through several electrical parameters extracted from the channel length scaling based method. Especially, the newly suggested current-voltage (I-V) contour map clearly elucidates the unique operation mechanism of the ambipolar SB-TFTs, governed by Schottky-junction between NiSi2 and Si-NW. Further, it reveals for the first-time in SB based FETs the important internal electrostatic coupling between the channel and externally applied voltages. This work provides helpful information for the realization of practical circuits with ambipolar SB-TFTs that can be transferred to different substrate technologies and applications.

LNG vapor barrier and obstacle evaluation: Wind-tunnel simulation of 1987 Falcon Spill Series. Final report, July 1987-February 1991

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shin, S.H.; Meroney, R.N.; Neff, D.E.

1991-03-01

Measurements of the behavior of simulated liquefied natural gas clouds dispersing over small-scale model placed in environmental wind tunnels permits evaluations of the fluid physics of dense cloud movement and dispersion in a controlled environment. A large data base on the interaction of simulated LNG plumes with the Falcon test configuration of vapor barrier fences and vortex generators was obtained. The purpose of the reported test program is to provide post-field-spill wind tunnel experiments to augment the LNG Vapor Fence Field Program data obtained during the Falcon Test Series in 1987. The goal of the program is to determine themore » probable response of a dense LNG Vapor cloud to vortex inducer obstacles and fences, examine the sensitivity of results to various scaling arguments which might augment limit, or extend the value of the field and wind-tunnel tests, and identify important details of the spill behavior which were not predicted during the pretest planning phase.« less

Implementing high-temperature short-time media treatment in commercial-scale cell culture manufacturing processes.

PubMed

Pohlscheidt, Michael; Charaniya, Salim; Kulenovic, Fikret; Corrales, Mahalia; Shiratori, Masaru; Bourret, Justin; Meier, Steven; Fallon, Eric; Kiss, Robert

2014-04-01

The production of therapeutic proteins by mammalian cell culture is complex and sets high requirements for process, facility, and equipment design, as well as rigorous regulatory and quality standards. One particular point of concern and significant risk to supply chain is the susceptibility to contamination such as bacteria, fungi, mycoplasma, and viruses. Several technologies have been developed to create barriers for these agents to enter the process, e.g. filtration, UV inactivation, and temperature inactivation. However, if not implemented during development of the manufacturing process, these types of process changes can have significant impact on process performance if not managed appropriately. This article describes the implementation of the high-temperature short-time (HTST) treatment of cell culture media as an additional safety barrier against adventitious agents during the transfer of a large-scale commercial cell culture manufacturing process. The necessary steps and experiments, as well as subsequent results during qualification runs and routine manufacturing, are shown.

Distributed rendering for multiview parallax displays

NASA Astrophysics Data System (ADS)

Annen, T.; Matusik, W.; Pfister, H.; Seidel, H.-P.; Zwicker, M.

2006-02-01

3D display technology holds great promise for the future of television, virtual reality, entertainment, and visualization. Multiview parallax displays deliver stereoscopic views without glasses to arbitrary positions within the viewing zone. These systems must include a high-performance and scalable 3D rendering subsystem in order to generate multiple views at real-time frame rates. This paper describes a distributed rendering system for large-scale multiview parallax displays built with a network of PCs, commodity graphics accelerators, multiple projectors, and multiview screens. The main challenge is to render various perspective views of the scene and assign rendering tasks effectively. In this paper we investigate two different approaches: Optical multiplexing for lenticular screens and software multiplexing for parallax-barrier displays. We describe the construction of large-scale multi-projector 3D display systems using lenticular and parallax-barrier technology. We have developed different distributed rendering algorithms using the Chromium stream-processing framework and evaluate the trade-offs and performance bottlenecks. Our results show that Chromium is well suited for interactive rendering on multiview parallax displays.

Recent patents on Cu/low-k dielectrics interconnects in integrated circuits.

PubMed

Jiang, Qing; Zhu, Yong F; Zhao, Ming

2007-01-01

In past decades, the development of microelectronics has moved along with constant speed of scaling to maximize transistor density as driven by the need for electrical and functional performance. For further development, the propagation velocity of electromagnetic waves becomes increasingly important due to their unyielding constraints on interconnect delay. To minimize it, it was forced to the introduction of the Cu/low-k dielectric interconnects to very large scale integrated circuits (VLSI) where k denotes the dielectric constant. In addition, reliable barrier structures, which are the thinnest part among the device parts to maximize space availability for the actual Cu IWs, are required to prevent penetration of different materials. In light of the above statements, this review will focus recent patents and some studies on Cu interconnects including Cu interconnect wires, low-k dielectrics and related barrier materials as well manufacturing techniques in VLSI, which are one of the most essential concerns in microelectronic industry and decides the further development of VLSI. In addition, possible future development in this field is considered.

Atomic oxygen production scaling in a nanosecond-pulsed externally grounded dielectric barrier plasma jet

NASA Astrophysics Data System (ADS)

Sands, Brian; Schmidt, Jacob; Ganguly, Biswa; Scofield, James

2014-10-01

Atomic oxygen production is studied in a capillary dielectric barrier plasma jet that is externally grounded and driven with a 20-ns risetime positive unipolar pulsed voltage at pulse repetition rates up to 25 kHz. The power coupled to the discharge can be easily increased by increasing the pulse repetition rate. At a critical turnover frequency, determined by the net energy density coupled to the discharge, the plasma chemistry abruptly changes. This is indicated by increased plasma conductance and a transition in reactive oxygen species production from an ozone-dominated production regime below the turnover frequency to atomic-oxygen-dominated production at higher pulse rates. Here, we characterize atomic oxygen production scaling using spatially- and temporally-resolved two-photon absorption laser-induced-fluorescence (TALIF). Quantitative results are obtained via calibration with xenon using a similar laser excitation and collection system. These results are compared with quantitative ozone and discharge power measurements using a helium gas flow with oxygen admixtures up to 3%.

Stochastic Spiking Neural Networks Enabled by Magnetic Tunnel Junctions: From Nontelegraphic to Telegraphic Switching Regimes

NASA Astrophysics Data System (ADS)

Liyanagedera, Chamika M.; Sengupta, Abhronil; Jaiswal, Akhilesh; Roy, Kaushik

2017-12-01

Stochastic spiking neural networks based on nanoelectronic spin devices can be a possible pathway to achieving "brainlike" compact and energy-efficient cognitive intelligence. The computational model attempt to exploit the intrinsic device stochasticity of nanoelectronic synaptic or neural components to perform learning or inference. However, there has been limited analysis on the scaling effect of stochastic spin devices and its impact on the operation of such stochastic networks at the system level. This work attempts to explore the design space and analyze the performance of nanomagnet-based stochastic neuromorphic computing architectures for magnets with different barrier heights. We illustrate how the underlying network architecture must be modified to account for the random telegraphic switching behavior displayed by magnets with low barrier heights as they are scaled into the superparamagnetic regime. We perform a device-to-system-level analysis on a deep neural-network architecture for a digit-recognition problem on the MNIST data set.

Exploring barriers and enablers for scaling up a community‐based grain bank intervention for improved infant and young child feeding in Ethiopia: A qualitative process evaluation

PubMed Central

Sako, Binta; Leerlooijer, Joanne N.; Lelisa, Azeb; Hailemariam, Abebe; Brouwer, Inge D.; Tucker Brown, Amal

2017-01-01

Abstract Child malnutrition remains high in Ethiopia, and inadequate complementary feeding is a contributing factor. In this context, a community‐based intervention was designed to provide locally made complementary food for children 6–23 months, using a bartering system, in four Ethiopian regions. After a pilot phase, the intervention was scaled up from 8 to 180 localities. We conducted a process evaluation to determine enablers and barriers for the scaling up of this intervention. Eight study sites were selected to perform 52 key informant interviews and 31 focus group discussions with purposely selected informants. For analysis, we used a framework describing six elements of successful scaling up: socio‐political context, attributes of the intervention, attributes of the implementers, appropriate delivery strategy, the adopting community, and use of research to inform the scale‐up process. A strong political will, alignment of the intervention with national priorities, and integration with the health care system were instrumental in the scaling up. The participatory approach in decision‐making reinforced ownership at community level, and training about complementary feeding motivated mothers and women's groups to participate. However, the management of the complex intervention, limited human resources, and lack of incentives for female volunteers proved challenging. In the bartering model, the barter rate was accepted, but the bartering was hindered by unavailability of cereals and limited financial and material resources to contribute, threatening the project's sustainability. Scaling up strategies for nutrition interventions require sufficient time, thorough planning, and assessment of the community's capacity to contribute human, financial, and material resources. PMID:29063698

Understanding the Spatial Scale of Genetic Connectivity at Sea: Unique Insights from a Land Fish and a Meta-Analysis.

PubMed

Cooke, Georgina M; Schlub, Timothy E; Sherwin, William B; Ord, Terry J

2016-01-01

Quantifying the spatial scale of population connectivity is important for understanding the evolutionary potential of ecologically divergent populations and for designing conservation strategies to preserve those populations. For marine organisms like fish, the spatial scale of connectivity is generally set by a pelagic larval phase. This has complicated past estimates of connectivity because detailed information on larval movements are difficult to obtain. Genetic approaches provide a tractable alternative and have the added benefit of estimating directly the reproductive isolation of populations. In this study, we leveraged empirical estimates of genetic differentiation among populations with simulations and a meta-analysis to provide a general estimate of the spatial scale of genetic connectivity in marine environments. We used neutral genetic markers to first quantify the genetic differentiation of ecologically-isolated adult populations of a land dwelling fish, the Pacific leaping blenny (Alticus arnoldorum), where marine larval dispersal is the only probable means of connectivity among populations. We then compared these estimates to simulations of a range of marine dispersal scenarios and to collated FST and distance data from the literature for marine fish across diverse spatial scales. We found genetic connectivity at sea was extensive among marine populations and in the case of A. arnoldorum, apparently little affected by the presence of ecological barriers. We estimated that ~5000 km (with broad confidence intervals ranging from 810-11,692 km) was the spatial scale at which evolutionarily meaningful barriers to gene flow start to occur at sea, although substantially shorter distances are also possible for some taxa. In general, however, such a large estimate of connectivity has important implications for the evolutionary and conservation potential of many marine fish communities.

Multi-scale simulation of lithium diffusion in the presence of a 30° partial dislocation and stacking fault in Si

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Chao-Ying; Li, Chen-liang; Wu, Guo-Xun

The multi-scale simulation method is employed to investigate how defects affect the performances of Li-ion batteries (LIBs). The stable positions, binding energies and dynamics properties of Li impurity in Si with a 30° partial dislocation and stacking fault (SF) have been studied in comparison with the ideal crystal. It is found that the most table position is the tetrahedral (T{sub d}) site and the diffusion barrier is 0.63 eV in bulk Si. In the 30° partial dislocation core and SF region, the most stable positions are at the centers of the octagons (Oct-A and Oct-B) and pentahedron (site S), respectively. Inmore » addition, Li dopant may tend to congregate in these defects. The motion of Li along the dislocation core are carried out by the transport among the Oct-A (Oct-B) sites with the barrier of 1.93 eV (1.12 eV). In the SF region, the diffusion barrier of Li is 0.91 eV. These two types of defects may retard the fast migration of Li dopant that is finally trapped by them. Thus, the presence of the 30° partial dislocation and SF may deactivate the Li impurity and lead to low rate capability of LIB.« less

Measurements of Effective Schottky Barrier in Inverse Extraordinary Optoconductance Structures

NASA Astrophysics Data System (ADS)

Tran, L. C.; Werner, F. M.; Solin, S. A.; Gilbertson, Adam; Cohen, L. F.

2013-03-01

Individually addressable optical sensors with dimensions as low as 250nm, fabricated from metal semiconductor hybrid structures (MSH) of AuTi-GaAs Schottky interfaces, display a transition from resistance decreasing with intensity in micron-scale sensors (Extraordinary Optoconductance, EOC) to resistance increasing with intensity in nano-scale sensors (Inverse Extraordinary Optoconductance I-EOC). I-EOC is attributed to a ballistic to diffusive crossover with the introduction of photo-induced carriers and gives rise to resistance changes of up to 9462% in 250nm devices. We characterize the photo-dependence of the effective Schottky barrier in EOC/I-EOC structures by the open circuit voltage and reverse bias resistance. Under illumination by a 5 mW, 632.8 nm HeNe laser, the barrier is negligible and the Ti-GaAs interface becomes Ohmic. Comparing the behavior of two devices, one with leads exposed, another with leads covered by an opaque epoxy, the variation in Voc with the position of the laser can be attributed to a photovoltaic effect of the lead metal and bulk GaAs. The resistance is unaffected by the photovoltaic offset of the leads, as indicated by the radial symmetry of 2-D resistance maps obtained by rastering a laser across EOC/IEOC devices. SAS has a financial interest in PixelEXX, a start-up company whose mission is to market imaging arrays.

Identifying Barriers and Pathways to Success for Renewable Energy Development on American Indian Lands

DOE Office of Scientific and Technical Information (OSTI.GOV)

Necefer, Len Edward; Jones, Thomas Elisha

American Indian tribes possess lands rich with renewable energy (RE) resources. Tribes have great potential and need to develop these resources, yet face a host of barriers that continue to impede development. Understanding these challenges as well as the pathways that can be taken to overcome them may facilitate more economic development to meet community needs and better position tribes to play a role in securing a low-carbon energy future for the United States. This paper presents the results of an expert elicitation of 24 tribal energy experts from federal, tribal, academic, and private industry backgrounds to identify barriers andmore » opportunities for federally recognized tribes in the lower 48 states. Experts identified a number of unique challenges facing tribes including financing and funding, infrastructure, tribal leadership and staff, state-level influence, and partnerships. Cultural factors were seen only to be of concern with large-scale development. Tribal sovereignty is a significant motivation for RE development and has yet to be fully realized. Cultural considerations are critical to the success of future projects; smaller residential and community-scale projects may be a better fit. Improving partnerships between tribes and the private sector can increase RE deployment and overcome historical distrust. States can have a double-ended influence on projects within tribal lands through taxation.« less

Large-scale fabrication of linear low density polyethylene/layered double hydroxides composite films with enhanced heat retention, thermal, mechanical, optical and water vapor barrier properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xie, Jiazhuo; Zhang, Kun; Zhao, Qinghua

Novel LDH intercalated with organic aliphatic long-chain anion was large-scale synthesized innovatively by high-energy ball milling in one pot. The linear low density polyethylene (LLDPE)/layered double hydroxides (LDH) composite films with enhanced heat retention, thermal, mechanical, optical and water vapor barrier properties were fabricated by melt blending and blowing process. FT IR, XRD, SEM results show that LDH particles were dispersed uniformly in the LLDPE composite films. Particularly, LLDPE composite film with 1% LDH exhibited the optimal performance among all the composite films with a 60.36% enhancement in the water vapor barrier property and a 45.73 °C increase in themore » temperature of maximum mass loss rate compared with pure LLDPE film. Furthermore, the improved infrared absorbance (1180–914 cm{sup −1}) of LLDPE/LDH films revealed the significant enhancement of heat retention. Therefore, this study prompts the application of LLDPE/LDH films as agricultural films with superior heat retention. - Graphical abstract: The fabrication process of LLDPE/LDH composite films. - Highlights: • LDH with basal spacing of 4.07 nm was synthesized by high-energy ball milling. • LLDPE composite films with homogeneous LDH dispersion were fabricated. • The properties of LLDPE/LDH composite films were improved. • LLDPE/LDH composite films show superior heat retention property.« less

Developing effective rockfall protection barriers for low energy impacts

NASA Astrophysics Data System (ADS)

Mentani, Alessio; Giacomini, Anna; Buzzi, Olivier; Govoni, Laura; Gottardi, Guido; Fityus, Stephen

2016-04-01

Recently, important progresses have been made towards the development of high capacity rockfall barriers (100 kJ - 8000 kJ). The interest of researchers and practitioners is now turning to the development of fences of minor capacity, whose use becomes essential in areas where rockfall events generally have low intensity and the use of high capacity barriers would be accompanied by excessive costs and high environmental impact. Low energy barriers can also provide a cost-effective solution even in areas where high energies events are expected. Results of full-scale tests are vital to any investigation on the behaviour of these structures. An experimental set-up has been developed at The University of Newcastle (AUS), to investigate the response of low energy rockfall barrier prototypes to low energy impacts. The Australian territory, and in particular New South Wales, is in fact characterised by rockfall events of low-to-medium intensity (50 kJ - 500 kJ) and the need of protection structures working within such energy range, is particularly felt [1]. The experiments involved the impact of a test block onto three spans, low energy barrier prototypes, made of steel structural posts, fully fixed at the base, side cables and a steel meshwork constituted by a double twist hexagonal wire net [2]. Test data enabled the development, calibration and assessment of FE models [3], on which non-linear and dynamic analyses have been performed addressing the effect of the block size. Results have shown that the response of the structure is strongly governed by the net. Data from tests conducted on the sole net and on the entire barrier showed in fact a similar trend, different to what typically observed for high capacity barriers, whose behaviour is also led by the presence of uphill cables and brakes. In particular, the numerical analyses have demonstrated a dependence of the net performance on the block size. In particular, a loss of capacity in the order of 50% occurred as the block size dropped from 1000 to 450 mm, with a realistic velocity observed to get the perforation of the net. The results of the study provide an important insight on the behaviour of low energy barriers. Data also shed an important light on the testing procedures which should be followed when full-scale experiments are performed on these structures, highlighting the need of considering the whole spectrum of potential block sizes. References [1] Spadari M, Kardani M, De Carteret R, Giacomini A, Buzzi O, Fityus S, Sloan S W (2013) Statistical evaluation of rockfall energy ranges for different geological settings of New South Wales, Australia. Eng Geol 158:57-65. [2] Thoeni K, Lambert C, Giacomini A, Sloan S W (2013) Discrete modelling of hexagonal wire meshes with a stochastically distorted contact model. Comp Geotech 49: 158-169. [3] Mentani A, Giacomini A, Buzzi O, Govoni L, Gottardi G, Fityus S (2015) Numerical Modelling of a Low-Energy Rockfall Barrier: New Insight into the Bullet Effect, Rock Mech Rock Eng, DOI10.1007/s00603-015-0803-1

Women׳s help-seeking behaviours for depressive symptoms during the perinatal period: Socio-demographic and clinical correlates and perceived barriers to seeking professional help.

PubMed

Fonseca, Ana; Gorayeb, Ricardo; Canavarro, Maria Cristina

2015-12-01

This study aims to characterize the help-seeking behaviours of women who were screened positive for perinatal depression, to investigate its sociodemographic and clinical correlates, and to characterize the perceived barriers that prevent women from seeking professional help. Cross-sectional internet survey. Participants were recruited through advertisements published in pamphlets and posted on social media websites (e.g., Facebook) and websites and forums that focused on pregnancy and childbirth. 656 women (currently pregnant or who had a baby during the last 12 months) completed the survey. Participants were assessed with the Edinburgh Postpartum Depression Scale, and were questioned about sociodemographic and clinical data, help-seeking behaviours and perceived barriers to help-seeking. Different pathways of help-seeking were found, with only 13.6% of women with a perinatal depression seeking help for their emotional problems. Married women, currently pregnant women, and women without history of psychological problems had a higher likelihood of not engaging in any type of help-seeking behaviour. The majority of women who had not sought professional assistance identified several barriers to help-seeking, particularly knowledge barriers. Strategies to increase women׳s help-seeking behaviours should be implemented, namely improving mental health literacy, introducing screening procedures for mental health problems in pre/postnatal health care settings, and offering women innovative opportunities (e.g., web-based tools) that allow them to overcome the practical barriers to help-seeking. Copyright © 2015 Elsevier Ltd. All rights reserved.

Two-dimensional time dependent hurricane overwash and erosion modeling at Santa Rosa Island

USGS Publications Warehouse

McCall, R.T.; Van Theil de Vries, J. S. M.; Plant, N.G.; Van Dongeren, A. R.; Roelvink, J.A.; Thompson, D.M.; Reniers, A.J.H.M.

2010-01-01

A 2DH numerical, model which is capable of computing nearshore circulation and morphodynamics, including dune erosion, breaching and overwash, is used to simulate overwash caused by Hurricane Ivan (2004) on a barrier island. The model is forced using parametric wave and surge time series based on field data and large-scale numerical model results. The model predicted beach face and dune erosion reasonably well as well as the development of washover fans. Furthermore, the model demonstrated considerable quantitative skill (upwards of 66% of variance explained, maximum bias - 0.21 m) in hindcasting the post-storm shape and elevation of the subaerial barrier island when a sheet flow sediment transport limiter was applied. The prediction skill ranged between 0.66 and 0.77 in a series of sensitivity tests in which several hydraulic forcing parameters were varied. The sensitivity studies showed that the variations in the incident wave height and wave period affected the entire simulated island morphology while variations in the surge level gradient between the ocean and back barrier bay affected the amount of deposition on the back barrier and in the back barrier bay. The model sensitivity to the sheet flow sediment transport limiter, which served as a proxy for unknown factors controlling the resistance to erosion, was significantly greater than the sensitivity to the hydraulic forcing parameters. If no limiter was applied the simulated morphological response of the barrier island was an order of magnitude greater than the measured morphological response.

Educational needs of health professionals working in rheumatology in Europe.

PubMed

Vliet Vlieland, Theodora P M; van den Ende, Cornelia H M; Alliot-Launois, Francoise; Beauvais, Catherine; Gobbo, Milena; Iagnocco, Annamaria; Lundberg, Ingrid E; Munuera-Martínez, Pedro V; Opava, Christina H; Prior, Yeliz; Redmond, Anthony; Smucrova, Hana; Wiek, Dieter

2016-01-01

To explore the availability of postgraduate education for health professionals (HPs) working in rheumatology in Europe, and their perceived educational needs and barriers for participation in current educational offerings. Structured interviews were conducted with national representatives of rheumatology HPs' organisations and an online survey among individual HPs was disseminated through existing European League Against Rheumatism (EULAR) networks (10 languages including English). These comprised questions on: availability of postgraduate education, familiarity with EULAR and its educational offerings, unmet needs regarding the contents and mode of delivery and potential barriers to participate in education (0-10 scales). According to 17 national representatives, postgraduate rheumatology education was most common for nurses, physical and occupational therapists. There were 1041 individuals responding to the survey, of whom 48% completed all questions. More than half (56%) were familiar with EULAR as an organisation, whereas <25% had attended the EULAR congress or were familiar with EULAR online courses. Educational needs regarding contents were highest for 'inflammatory arthritis' and 'connective tissue diseases' and regarding modes of delivery for 'courses organised in own country' and 'online courses'. Important barriers to participation included lack of 'resources', 'time' and 'English language skills'. Overall, there was considerable variation in needs and barriers among countries. There is a lack of postgraduate rheumatology education for HPs in most countries. There are opportunities to raise awareness regarding EULAR educational offerings and to develop courses provided in HPs' own country, tailored to national needs and barriers and taking language barriers into consideration.

Development and Evaluation of Season-ahead Precipitation and Streamflow Predictions for Sectoral Management in Western Ethiopia

NASA Astrophysics Data System (ADS)

Block, P. J.; Alexander, S.; WU, S.

2017-12-01

Skillful season-ahead predictions conditioned on local and large-scale hydro-climate variables can provide valuable knowledge to farmers and reservoir operators, enabling informed water resource allocation and management decisions. In Ethiopia, the potential for advancing agriculture and hydropower management, and subsequently economic growth, is substantial, yet evidence suggests a weak adoption of prediction information by sectoral audiences. To address common critiques, including skill, scale, and uncertainty, probabilistic forecasts are developed at various scales - temporally and spatially - for the Finchaa hydropower dam and the Koga agricultural scheme in an attempt to promote uptake and application. Significant prediction skill is evident across scales, particularly for statistical models. This raises questions regarding other potential barriers to forecast utilization at community scales, which are also addressed.

Scaling Up of Breastfeeding Promotion Programs in Low- and Middle-Income Countries: the “Breastfeeding Gear” Model12

PubMed Central

Pérez-Escamilla, Rafael; Curry, Leslie; Minhas, Dilpreet; Taylor, Lauren; Bradley, Elizabeth

2012-01-01

Breastfeeding (BF) promotion is one of the most cost-effective interventions to advance mother–child health. Evidence-based frameworks and models to promote the effective scale up and sustainability of BF programs are still lacking. A systematic review of peer-reviewed and gray literature reports was conducted to identify key barriers and facilitators for scale up of BF programs in low- and middle-income countries. The review identified BF programs located in 28 countries in Africa, Latin America and the Caribbean, and Asia. Study designs included case studies, qualitative studies, and observational quantitative studies. Only 1 randomized, controlled trial was identified. A total of 22 enabling factors and 15 barriers were mapped into a scale-up framework termed “AIDED” that was used to build the parsimonious breastfeeding gear model (BFGM). Analogous to a well-oiled engine, the BFGM indicates the need for several key “gears” to be working in synchrony and coordination. Evidence-based advocacy is needed to generate the necessary political will to enact legislation and policies to protect, promote, and support BF at the hospital and community levels. This political-policy axis in turn drives the resources needed to support workforce development, program delivery, and promotion. Research and evaluation are needed to sustain the decentralized program coordination “gear” required for goal setting and system feedback. The BFGM helps explain the different levels of performance in national BF outcomes in Mexico and Brazil. Empirical research is recommended to further test the usefulness of the AIDED framework and BFGM for global scaling up of BF programs. PMID:23153733

Evaluation of GE-167 Silicone Rubber (RTV) For Possible Service As A Moisture-Barrier For Certain Strain Gage Applications

NASA Technical Reports Server (NTRS)

Hare, David A.; Moore, Thomas C., Sr.

2000-01-01

The Langley Research Center uses strain gages in a wide variety of demanding test environments. Strain gage installations, depending on the testing scenario, may see high temperatures, cryogenic temperature, moisture accumulation, mechanical abuse, or any combination of these conditions. At Langley, there is often a need to provide protection for strain gages against moisture and mechanical abuse, especially when large-scale, harsh environment testing is to be encountered. This technical memorandum discusses the evaluation of a room temperature curing silicone rubber sealant manufactured by the General Electric Company for consideration as a moisture-barrier for certain strain gage installations.

The development and implementation of a theory-informed, integrated mother-child intervention in rural Uganda.

PubMed

Singla, Daisy R; Kumbakumba, Elias

2015-12-01

A randomised cluster effectiveness trial of a parenting intervention in rural Uganda found benefits to child development among children 12-36 months, relevant parenting practices related to stimulation, hygiene and diet, and prevented the worsening of mothers' depressive symptoms. An examination of underlying implementation processes allows researchers and program developers to determine whether the program was implemented as intended and highlight barriers and facilitators that may influence replication and scale-up. The objectives of this study were to describe and critically examine (a) perceived barriers and facilitators related to implementation processes of intervention content, training and supervision and delivery from the perspectives of delivery agents and supervisors; (b) perceived barriers and facilitators related to enactment of practices from the perspective of intervention mothers participating in the parenting program; and c) whether the program was implemented as intended. Semi-structured interviews were conducted at midline with peer delivery agents (n = 12) and intervention mothers (n = 31) and at endline with supervisors (n = 4). Content analysis was used to analyze qualitative data in terms of barriers and facilitators of intervention content, training and supervision, delivery and enactment. Additionally, mothers' recall and enactment of practices were coded and analyzed statistically. Monitoring of group sessions and home visits were examined to reveal whether the program was implemented as intended. Among the program's five key messages, 'love and respect' targeting maternal psychological well-being was the most practiced by mothers, easiest to implement by delivery agents, and mothers reported the most internal facilitators for this message. A detailed manual and structured monitoring forms were perceived to facilitate training, intervention delivery, and supervision. Interactive and active strategies based on social-cognitive learning theory were reported as facilitators to intervention delivery. Only program attendance, but not barriers, facilitators or message recall, was significantly positively related to message enactment. Monitoring of group sessions and home visits showed that the program was largely implemented as intended. This implementation assessment revealed a number of important barriers and facilitators from the perspectives of delivery agents, supervisors and program participants. The methods and results are useful to examining and informing the content, delivery, and scaling up of the current program as well as future mother-child interventions in LMIC settings. Copyright © 2015 Elsevier Ltd. All rights reserved.

Test Design Considerations for Students with Significant Cognitive Disabilities

ERIC Educational Resources Information Center

Anderson, Daniel; Farley, Dan; Tindal, Gerald

2015-01-01

Students with significant cognitive disabilities present an assessment dilemma that centers on access and validity in large-scale testing programs. Typically, access is improved by eliminating construct-irrelevant barriers, while validity is improved, in part, through test standardization. In this article, one state's alternate assessment data…

Progress toward a low budget reference grade genome assembly

USDA-ARS?s Scientific Manuscript database

Reference quality de novo genome assemblies were once solely the domain of large, well-funded genome projects. While next-generation short read technology removed some of the cost barriers, accurate chromosome-scale assembly remains a real challenge. Here we present efforts to de novo assemble the...

Adult Career Changers: A Developmental Context.

ERIC Educational Resources Information Center

Lucas, Margaretha S.

1999-01-01

Adults requesting career guidance at a counseling center completed a problem-checklist and the Identity, Information, and Barriers scales of the My Vocational Situation inventory. Respondents indicated a need for information on careers; lack of clarity regarding interests, talents, and goals; and worries about self-confidence, independence, and…

SODIUM DITHIONITE INJECTIONS USED FOR CHROMIUM REDUCTION

EPA Science Inventory

A field-scale pilot study was conducted in 1999 at the U.S. Coast Guard Support Center in Elizabeth City, NC, to evaluate the effectiveness of injecting sodium dithionite into the upper aquifer and lower vadose zone to create a permeable reactive barrier (PRB) system utilizing na...

Using the ICF's environmental factors framework to develop an item bank measuring built and natural environmental features affecting persons with disabilities.

PubMed

Heinemann, Allen W; Lai, Jin-Shei; Wong, Alex; Dashner, Jessica; Magasi, Susan; Hahn, Elizabeth A; Carlozzi, Noelle E; Tulsky, David S; Jerousek, Sara; Semik, Patrick; Miskovic, Ana; Gray, David B

2016-11-01

To develop a measure of natural environment and human-made change features (Chapter 2 of the international classification of functioning, disability, and health) and evaluate the influence of perceived barriers on health-related quality of life. A sample of 570 adults with stroke, spinal cord injury, and traumatic brain injury residing in community settings reported their functioning in home, outdoor, and community settings (mean age = 47.0 years, SD = 16.1). They rated 18 items with a 5-point rating scale to describe the influence of barriers to moving around, seeing objects, hearing sounds, hearing conversations, feeling safe, and regulating temperature and indicated whether any difficulties were due to environmental features. We used Rasch analysis to identify misfitting items and evaluate differential item functioning (DIF) across impairment groups. We computed correlations between barriers and patient-reported outcomes measurement information system (PROMIS) social domain measures and community participation indicators (CPI) measures. The 18 items demonstrated person reliability of .70, discriminating nearly three levels of barriers. All items fit the Rasch model; impairment-related DIF was negligible. Ceiling effects were negligible, but 25 % of the respondents were at the floor, indicating that they did not experience barriers that they attributed to the built and natural environment. As anticipated, barriers correlated moderately with PROMIS and CPI variables, suggesting that although this new item bank measures a construct that is related to participation and health-related quality of life, it also captures something unique. Known-groups validity was supported by wheelchair users reporting a higher level of barriers than did ambulatory respondents. Preliminary evidence supports the reliability and validity of this new measure of barriers to the built and natural environment. This measure allows investigators and clinicians to measure perceptions of the natural environment and human-made changes, providing information that can guide interventions to reduce barriers. Moderate relationships between barriers and PROMIS and CPI variables provide support for the measurement and theory of environmental influences on social health and participation.

Investigating the complementary value of discrete choice experiments for the evaluation of barriers and facilitators in implementation research: a questionnaire survey

PubMed Central

van Helvoort-Postulart, Debby; van der Weijden, Trudy; Dellaert, Benedict GC; de Kok, Mascha; von Meyenfeldt, Maarten F; Dirksen, Carmen D

2009-01-01

Background The potential barriers and facilitators to change should guide the choice of implementation strategy. Implementation researchers believe that existing methods for the evaluation of potential barriers and facilitators are not satisfactory. Discrete choice experiments (DCE) are relatively new in the health care sector to investigate preferences, and may be of value in the field of implementation research. The objective of our study was to investigate the complementary value of DCE for the evaluation of barriers and facilitators in implementation research. Methods Clinical subject was the implementation of the guideline for breast cancer surgery in day care. We identified 17 potential barriers and facilitators to the implementation of this guideline. We used a traditional questionnaire that was made up of statements about the potential barriers and facilitators. Respondents answered 17 statements on a five-point scale ranging from one (fully disagree) to five (fully agree). The potential barriers and facilitators were included in the DCE as decision attributes. Data were gathered among anaesthesiologists, surgical oncologists, and breast care nurses by means of a paper-and-pencil questionnaire. Results The overall response was 10%. The most striking finding was that the responses to the traditional questionnaire hardly differentiated between barriers. Forty-seven percent of the respondents thought that DCE is an inappropriate method. These respondents considered DCE too difficult and too time-consuming. Unlike the traditional questionnaire, the results of a DCE provide implementation researchers and clinicians with a relative attribute importance ranking that can be used to prioritize potential barriers and facilitators to change, and hence to better fine-tune the implementation strategies to the specific problems and challenges of a particular implementation process. Conclusion The results of our DCE and traditional questionnaire would probably lead to different implementation strategies. Although there is no 'gold standard' for prioritising potential barriers and facilitators to the implementation of change, theoretically, DCE would be the method of choice. However, the feasibility of using DCE was less favourable. Further empirical applications should investigate whether DCE can really make a valuable contribution to the implementation science. PMID:19250555

Barriers to participation in global surgery academic collaborations, and possible solutions: a qualitative study.

PubMed

Fallah, Parisa Nicole; Bernstein, Mark

2018-04-06

OBJECTIVE There is a global lack of access to surgical care, and this issue disproportionately affects those in low- and middle-income countries. Global surgery academic collaborations (GSACs) between surgeons in high-income countries and those in low- and middle-income countries are one possible sustainable way to address the global surgical need. The objective of this study was to examine the barriers to participation in GSACs and to suggest ways to increase involvement. METHODS A convenience sample of 86 surgeons, anesthesiologists, other physicians, residents, fellows, and nurses from the US, Canada, and Norway was used. Participants were all health care providers from multiple specialties and multiple academic centers with varied involvement in GSACs. More than half of the participants were neurosurgeons. Participants were interviewed in person or over Skype in Toronto over the course of 2 months by using a predetermined set of open-ended questions. Thematic content analysis was used to evaluate the participants' responses. RESULTS Based on the data, 3 main themes arose that pointed to individual, community, and system barriers for involvement in GSACs. Individual barriers included loss of income, family commitments, young career, responsibility to local patients, skepticism of global surgery efforts, ethical concerns, and safety concerns. Community barriers included insufficient mentorship and lack of support from colleagues. System barriers included lack of time, minimal academic recognition, insufficient awareness, insufficient administrative support and organization, and low political and funding support. CONCLUSIONS Steps can be taken to address some of these barriers and to increase the involvement of surgeons from high-income countries in GSACs. This could lead to a necessary scale-up of global surgery efforts that may help increase worldwide access to surgical care.

The effects of airbags and seatbelts on occupant injury in longitudinal barrier crashes.

PubMed

Gabauer, Douglas J; Gabler, Hampton C

2010-02-01

Longitudinal barriers, such as guardrails, are designed to prevent a vehicle that leaves the roadway from impacting a more dangerous object while minimizing the risk of injury to the vehicle occupants. Current full-scale test procedures for these devices do not consider the effect of occupant restraints such as seatbelts and airbags. The purpose of this study was to determine the extent to which restraints are used or deployed in longitudinal barrier collisions and their subsequent effect on occupant injury. Binary logistic regression models were generated to predict occupant injury risk using data from the National Automotive Sampling System / Crashworthiness Data System from 1997 through 2007. In tow-away longitudinal barrier crashes, airbag deployment rates were 70% for airbag-equipped vehicles. Compared with unbelted occupants without an airbag available, seat belt restrained occupants with an airbag available had a dramatically decreased risk of receiving a serious (MAIS 3+) injury (odds-ratio (OR)=0.03; 95% CI: 0.004-0.24). A similar decrease was observed among those restrained by seat belts, but without an airbag available (OR=0.03; 95% CI: 0.001- 0.79). No significant differences in risk of serious injuries were observed between unbelted occupants with an airbag available compared with unbelted occupants without an airbag available (OR=0.53; 95% CI=0.10-2.68). This study refutes the perception in the roadside safety community that airbags rarely deploy in frontal barrier crashes, and suggests that current longitudinal barrier occupant risk criteria may over-estimate injury potential for restrained occupants involved in a longitudinal barrier crash. Copyright 2010 Elsevier Ltd. All rights reserved.

[Barriers and motivations of nurses for conducting research in Intensive Care Units and Emergency Medical Service].

PubMed

Llauradó-Serra, M; Güell-Baró, R; Castanera-Duro, A; Sandalinas, I; Argilaga, E; Fortes-Del Valle, M L; Jiménez-Herrera, M F; Bordonado-Pérez, L; Fuentes-Pumarola, C

The implementation of evidence based practice is essential in clinical practice. However, it is still a challenge in critical care patients. To identify the barriers for conducting research that nursing professionals perceive in intensive care and medical emergency departments, as well as to investigate the areas of interest and motivations to carry out research projects. Cross-sectional and multicentre study carried out in 4 intensive care units and in one Medical Emergency Department emergency pre-hospital carein Catalonia on 2014. The instrument used was The Barriers to Research Utilization Scale which had been previously validated into Spanish. A descriptive and bivariate analysis was performed. A statistical significance of P<.05 was assumed. One hundred seventy-two questionnaires were obtained (69.9% response). Of the total, 135 were from critical care, 27 to pre-hospital care, and 10 from both. Just over half (57.3%) had research experience, although 44.4% had related training. The questionnaire dimension considered most relevant was organisational characteristics. The most important barriers were: there is not enough time at work [3.11 (SD 1.21)], physicians do not collaborate in its implementation [2.99 (SD 1.22)], and nurses are isolated with respect to other professionals [2.86 (SD 1.32)]. Significant differences were observed in the barriers according to research experience and work place. The main motivation was to be updated in critical patient care. The main barriers perceived are related to the organisation. There are differences in the barriers according to research experience and work place. Copyright © 2016 Elsevier España, S.L.U. y SEEIUC. All rights reserved.

Barriers to access to care reported by women living with HIV across 27 countries.

PubMed

Johnson, Margaret; Samarina, Anna; Xi, He; Valdez Ramalho Madruga, José; Hocqueloux, Laurent; Loutfy, Mona; Fournelle, Marie-Josée; Norton, Michael; Van Wyk, Jean; Zachry, Woodie; Martinez, Marisol

2015-01-01

Increased access to successful antiretroviral therapy (ART) is necessary in order to achieve an AIDS-free generation. Importantly, slightly over half of the people living with HIV are women. Small studies have described many barriers to accessing treatment and care among women living with HIV. This cross-sectional, non-interventional, epidemiological study assessed the prevalence of barriers to accessing care for women living with HIV across 27 countries, divided into four global regions. HIV-positive women attending routine clinical visits were offered the opportunity to participate in the study. Data describing the study sites and demographic characteristics of the participating women were collected. Participating women filled out questionnaires including the Barriers to Care Scale (BACS) questionnaire, on which they reported the extent to which they found each of the 12 potential barriers to accessing health care problematic. A total of 1931 women living with HIV were included in the study: 760 from Western Europe and Canada (WEC), 532 from Central and Eastern Europe (CEE), 519 from Latin America (LA), and 120 from China. The mean age of participating women was 40.1 ± 11.4 years. A total of 88.2% were currently taking ART. A total of 81.8% obtained HIV treatment under a government health plan. The most prevalent barrier to care was community HIV/AIDS stigma. Community HIV/AIDS knowledge, lack of supportive/understanding work environments, lack of employment opportunities, and personal financial resources were also highly prevalent barriers to accessing care. These findings indicate that, more than 30 years after the start of the AIDS epidemic, stigma is still a major issue for women living with HIV. Continued efforts are needed to improve community education on HIV/AIDS in order to maximize access to health care among women living with HIV.

Barriers to access to care reported by women living with HIV across 27 countries

PubMed Central

Johnson, Margaret; Samarina, Anna; Xi, He; Valdez Ramalho Madruga, José; Hocqueloux, Laurent; Loutfy, Mona; Fournelle, Marie-Josée; Norton, Michael; Van Wyk, Jean; Zachry, Woodie; Martinez, Marisol

2015-01-01

Increased access to successful antiretroviral therapy (ART) is necessary in order to achieve an AIDS-free generation. Importantly, slightly over half of the people living with HIV are women. Small studies have described many barriers to accessing treatment and care among women living with HIV. This cross-sectional, non-interventional, epidemiological study assessed the prevalence of barriers to accessing care for women living with HIV across 27 countries, divided into four global regions. HIV-positive women attending routine clinical visits were offered the opportunity to participate in the study. Data describing the study sites and demographic characteristics of the participating women were collected. Participating women filled out questionnaires including the Barriers to Care Scale (BACS) questionnaire, on which they reported the extent to which they found each of the 12 potential barriers to accessing health care problematic. A total of 1931 women living with HIV were included in the study: 760 from Western Europe and Canada (WEC), 532 from Central and Eastern Europe (CEE), 519 from Latin America (LA), and 120 from China. The mean age of participating women was 40.1 ± 11.4 years. A total of 88.2% were currently taking ART. A total of 81.8% obtained HIV treatment under a government health plan. The most prevalent barrier to care was community HIV/AIDS stigma. Community HIV/AIDS knowledge, lack of supportive/understanding work environments, lack of employment opportunities, and personal financial resources were also highly prevalent barriers to accessing care. These findings indicate that, more than 30 years after the start of the AIDS epidemic, stigma is still a major issue for women living with HIV. Continued efforts are needed to improve community education on HIV/AIDS in order to maximize access to health care among women living with HIV. PMID:26168817

Perceived exercise barriers are reduced and benefits are improved with lifestyle modification in overweight and obese women with polycystic ovary syndrome: a randomised controlled trial.

PubMed

Thomson, Rebecca L; Buckley, Jonathan D; Brinkworth, Grant D

2016-03-09

This study assessed the perceived benefits and barriers to exercise participation in overweight and obese women with polycystic ovary syndrome (PCOS) and monitored changes in response to a lifestyle intervention. Forty-three overweight/obese PCOS women (Age, 30.3(6.2) yrs; BMI, 36.4(5.6) kg/m(2)) were randomised to one of three 20-week lifestyle programs: diet only (DO, n = 13), diet and aerobic exercise (DA, n = 11) and diet and combined aerobic-resistance exercise (DC, n = 19). Exercise Benefits/Barriers Scale (EBBS), weight, aerobic fitness, depression and PCOS specific health-related quality of life were measured. Barriers score was related to depression (r = 0.45, P = 0.002) and aerobic fitness (r = -0.32, P = 0.04), while benefits score was related to aerobic fitness (r = 0.41, P = 0.007). EBBS, benefits and barriers scores improved overtime (P ≤ 0.001). Benefits subscales psychological outlook and social interaction increased (P ≤ 0.001) and life enhancement and preventative health did not change (P ≥ 0.3). Physical performance increased only in DA (P = 0.009). There were no differences between treatments for any of the other subscales (P ≥ 0.2). Barriers subscales exercise milieu, time expenditure and physical exertion reduced (P ≤ 0.003) and family discouragement did not change (P = 0.6). This study demonstrated that lifestyle modification consisting of an energy-restricted diet with or without exercise training improved the perceived benefits from and barriers to exercise. Australian New Zealand Clinical Trials Register ACTRN12606000198527, registered 26 May 2006.

Scaling up a tobacco control intervention in low resource settings: a case example for school teachers in India.

PubMed

Pednekar, M S; Nagler, E M; Gupta, P C; Pawar, P S; Mathur, N; Adhikari, K; Codeira, L S; Stoddard, A M; Sorensen, G

2018-06-01

Research on processes of bringing effective tobacco control interventions to scale to increase quit rates among tobacco users is uncommon. This study examines processes to bring to scale one such intervention for school teachers, i.e. Tobacco Free Teacher-Tobacco Free Society (TFT-TFS). This intervention provides a foundation for an effective and low cost approach to promote cessation through schools. The present study was conducted in the states of Bihar and Maharashtra in 2014 using quantitative and qualitative methods. Focus group discussions (FGDs) were analysed using immersion crystallization method. The data presented are from a survey of 291 principals and seven FGDs. This study examined characteristics of principals and teachers, organizational environment, external environmental factors and program characteristics to determine facilitators and barriers for successful dissemination and implementation of the TFT-TFS program. Some facilitators were, incorporation of the program in existing channels like staff meetings and trainings, certification and recognition by the department of education; while some barriers were routine time bound duties (mainly teaching) of teachers and prevalence of tobacco use among teachers and administrators. Principals and teachers expressed a need and high level of interest in the adoption and implementation of the TFT-TFS program in their schools.

Target detection and localization in shallow water: an experimental demonstration of the acoustic barrier problem at the laboratory scale.

PubMed

Marandet, Christian; Roux, Philippe; Nicolas, Barbara; Mars, Jérôme

2011-01-01

This study demonstrates experimentally at the laboratory scale the detection and localization of a wavelength-sized target in a shallow ultrasonic waveguide between two source-receiver arrays at 3 MHz. In the framework of the acoustic barrier problem, at the 1/1000 scale, the waveguide represents a 1.1-km-long, 52-m-deep ocean acoustic channel in the kilohertz frequency range. The two coplanar arrays record in the time-domain the transfer matrix of the waveguide between each pair of source-receiver transducers. Invoking the reciprocity principle, a time-domain double-beamforming algorithm is simultaneously performed on the source and receiver arrays. This array processing projects the multireverberated acoustic echoes into an equivalent set of eigenrays, which are defined by their launch and arrival angles. Comparison is made between the intensity of each eigenray without and with a target for detection in the waveguide. Localization is performed through tomography inversion of the acoustic impedance of the target, using all of the eigenrays extracted from double beamforming. The use of the diffraction-based sensitivity kernel for each eigenray provides both the localization and the signature of the target. Experimental results are shown in the presence of surface waves, and methodological issues are discussed for detection and localization.