Active contour-based visual tracking by integrating colors, shapes, and motions.

PubMed

Hu, Weiming; Zhou, Xue; Li, Wei; Luo, Wenhan; Zhang, Xiaoqin; Maybank, Stephen

2013-05-01

In this paper, we present a framework for active contour-based visual tracking using level sets. The main components of our framework include contour-based tracking initialization, color-based contour evolution, adaptive shape-based contour evolution for non-periodic motions, dynamic shape-based contour evolution for periodic motions, and the handling of abrupt motions. For the initialization of contour-based tracking, we develop an optical flow-based algorithm for automatically initializing contours at the first frame. For the color-based contour evolution, Markov random field theory is used to measure correlations between values of neighboring pixels for posterior probability estimation. For adaptive shape-based contour evolution, the global shape information and the local color information are combined to hierarchically evolve the contour, and a flexible shape updating model is constructed. For the dynamic shape-based contour evolution, a shape mode transition matrix is learnt to characterize the temporal correlations of object shapes. For the handling of abrupt motions, particle swarm optimization is adopted to capture the global motion which is applied to the contour in the current frame to produce an initial contour in the next frame.

Object segmentation using graph cuts and active contours in a pyramidal framework

NASA Astrophysics Data System (ADS)

Subudhi, Priyambada; Mukhopadhyay, Susanta

2018-03-01

Graph cuts and active contours are two very popular interactive object segmentation techniques in the field of computer vision and image processing. However, both these approaches have their own well-known limitations. Graph cut methods perform efficiently giving global optimal segmentation result for smaller images. However, for larger images, huge graphs need to be constructed which not only takes an unacceptable amount of memory but also increases the time required for segmentation to a great extent. On the other hand, in case of active contours, initial contour selection plays an important role in the accuracy of the segmentation. So a proper selection of initial contour may improve the complexity as well as the accuracy of the result. In this paper, we have tried to combine these two approaches to overcome their above-mentioned drawbacks and develop a fast technique of object segmentation. Here, we have used a pyramidal framework and applied the mincut/maxflow algorithm on the lowest resolution image with the least number of seed points possible which will be very fast due to the smaller size of the image. Then, the obtained segmentation contour is super-sampled and and worked as the initial contour for the next higher resolution image. As the initial contour is very close to the actual contour, so fewer number of iterations will be required for the convergence of the contour. The process is repeated for all the high-resolution images and experimental results show that our approach is faster as well as memory efficient as compare to both graph cut or active contour segmentation alone.

Interaction of perceived neighborhood walkability and self-efficacy on physical activity.

PubMed

Kaczynski, Andrew T; Robertson-Wilson, Jennifer; Decloe, Melissa

2012-02-01

Few social ecological studies have considered the joint effects of intrapersonal and environmental influences on physical activity. This study investigated the interaction of self-efficacy and perceived neighborhood walkability in predicting neighborhood-based physical activity and how this relationship varied by gender and body mass index. Data were derived from a cross-sectional investigation of environmental and psychosocial correlates of physical activity among adults (n = 585). Participants completed a detailed 7-day physical activity log booklet, along with a questionnaire that included measures of neighborhood walkability, self-efficacy, and several sociodemographic items. Factorial analysis of variance tests were used to examine the main effects of and interaction between walkability and self-efficacy. In predicting neighborhood-based physical activity, significant interactions were observed between self-efficacy and neighborhood walkability for females (but not for males) and for overweight/obese participants (but not for healthy weight individuals). Women and overweight/obese individuals with low self-efficacy demonstrated substantially greater physical activity when living in a high walkable neighborhood. Physical activity research and promotion efforts should take into account both environmental and personal factors and the interrelationships between them that influence active living.

Brain tumor segmentation with Vander Lugt correlator based active contour.

PubMed

Essadike, Abdelaziz; Ouabida, Elhoussaine; Bouzid, Abdenbi

2018-07-01

The manual segmentation of brain tumors from medical images is an error-prone, sensitive, and time-absorbing process. This paper presents an automatic and fast method of brain tumor segmentation. In the proposed method, a numerical simulation of the optical Vander Lugt correlator is used for automatically detecting the abnormal tissue region. The tumor filter, used in the simulated optical correlation, is tailored to all the brain tumor types and especially to the Glioblastoma, which considered to be the most aggressive cancer. The simulated optical correlation, computed between Magnetic Resonance Images (MRI) and this filter, estimates precisely and automatically the initial contour inside the tumorous tissue. Further, in the segmentation part, the detected initial contour is used to define an active contour model and presenting the problematic as an energy minimization problem. As a result, this initial contour assists the algorithm to evolve an active contour model towards the exact tumor boundaries. Equally important, for a comparison purposes, we considered different active contour models and investigated their impact on the performance of the segmentation task. Several images from BRATS database with tumors anywhere in images and having different sizes, contrast, and shape, are used to test the proposed system. Furthermore, several performance metrics are computed to present an aggregate overview of the proposed method advantages. The proposed method achieves a high accuracy in detecting the tumorous tissue by a parameter returned by the simulated optical correlation. In addition, the proposed method yields better performance compared to the active contour based methods with the averages of Sensitivity=0.9733, Dice coefficient = 0.9663, Hausdroff distance = 2.6540, Specificity = 0.9994, and faster with a computational time average of 0.4119 s per image. Results reported on BRATS database reveal that our proposed system improves over the recently published

Method of the active contour for segmentation of bone systems on bitmap images

NASA Astrophysics Data System (ADS)

Vu, Hai Anh; Safonov, Roman A.; Kolesnikova, Anna S.; Kirillova, Irina V.; Kossovich, Leonid U.

2018-02-01

It is developed within a method of the active contours the approach, which is allowing to realize separation of a contour of a object of the image in case of its segmentation. This approach exceeds a parametric method on speed, but also does not concede to it on decision accuracy. The approach is offered within this operation will allow to realize allotment of a contour with high accuracy of the image and quicker than a parametric method of the active contours.

Are perceived neighborhood hazards a barrier to physical activity in children?

PubMed

Romero, A J; Robinson, T N; Kraemer, H C; Erickson, S J; Haydel, K F; Mendoza, F; Killen, J D

2001-10-01

We hypothesized that children's perceptions of more neighborhood hazards would be associated with less physical activity, less aerobic fitness, and a higher body mass index. To examine the association between a hazardous neighborhood context and physical activity in children. Fourth-grade students (n = 796) of diverse ethnic and economic backgrounds completed measures of neighborhood hazards, self-reported physical activity, physical fitness, height, and weight. Parents (n = 518) completed telephone interviews and provided data on their education level and occupation. As expected, children from families of lower socioeconomic status perceived significantly more neighborhood hazards. Contrary to our hypothesis, the perception of more hazards was significantly associated with more reported physical activity. This finding was not explained by school heterogeneity, alteration of the hazards measure, or differences in socioeconomic status. To further examine the relationship between neighborhood hazards and physical activity, we suggest that future studies include assessments of sedentary behavior, parental fear of violence, parental regulation of children's leisure activities, and cost and quality of available play areas and organized sports.

Housing, the Neighborhood Environment, and Physical Activity among Older African Americans

PubMed Central

Hannon, Lonnie; Sawyer, Patricia; Allman, Richard M.

2013-01-01

This study examines the association of neighborhood environment, as measured by housing factors, with physical activity among older African Americans. Context is provided on the effects of structural inequality as an inhibitor of health enhancing neighborhood environments. The study population included African Americans participating in the UAB Study of Aging (n=433). Participants demonstrated the ability to walk during a baseline in-home assessment. The strength and independence of housing factors were assessed using neighborhood walking for exercise as the outcome variable. Sociodemographic data, co-morbid medical conditions, and rural/urban residence were included as independent control factors. Homeownership, occupancy, and length of residency maintained positive associations with neighborhood walking independent of control factors. Housing factors appear to be predictive of resident engagement in neighborhood walking. Housing factors, specifically high rates of homeownership, reflect functional and positive neighborhood environments conducive for physical activity. Future interventions seeking to promote health-enhancing behavior should focus on developing housing and built-environment assets within the neighborhood environment. PMID:23745172

Recognizing Spoken Words: The Neighborhood Activation Model

PubMed Central

Luce, Paul A.; Pisoni, David B.

2012-01-01

Objective A fundamental problem in the study of human spoken word recognition concerns the structural relations among the sound patterns of words in memory and the effects these relations have on spoken word recognition. In the present investigation, computational and experimental methods were employed to address a number of fundamental issues related to the representation and structural organization of spoken words in the mental lexicon and to lay the groundwork for a model of spoken word recognition. Design Using a computerized lexicon consisting of transcriptions of 20,000 words, similarity neighborhoods for each of the transcriptions were computed. Among the variables of interest in the computation of the similarity neighborhoods were: 1) the number of words occurring in a neighborhood, 2) the degree of phonetic similarity among the words, and 3) the frequencies of occurrence of the words in the language. The effects of these variables on auditory word recognition were examined in a series of behavioral experiments employing three experimental paradigms: perceptual identification of words in noise, auditory lexical decision, and auditory word naming. Results The results of each of these experiments demonstrated that the number and nature of words in a similarity neighborhood affect the speed and accuracy of word recognition. A neighborhood probability rule was developed that adequately predicted identification performance. This rule, based on Luce's (1959) choice rule, combines stimulus word intelligibility, neighborhood confusability, and frequency into a single expression. Based on this rule, a model of auditory word recognition, the neighborhood activation model, was proposed. This model describes the effects of similarity neighborhood structure on the process of discriminating among the acoustic-phonetic representations of words in memory. The results of these experiments have important implications for current conceptions of auditory word recognition in

Segmentation and tracking in echocardiographic sequences: active contours guided by optical flow estimates

NASA Technical Reports Server (NTRS)

Mikic, I.; Krucinski, S.; Thomas, J. D.

1998-01-01

This paper presents a method for segmentation and tracking of cardiac structures in ultrasound image sequences. The developed algorithm is based on the active contour framework. This approach requires initial placement of the contour close to the desired position in the image, usually an object outline. Best contour shape and position are then calculated, assuming that at this configuration a global energy function, associated with a contour, attains its minimum. Active contours can be used for tracking by selecting a solution from a previous frame as an initial position in a present frame. Such an approach, however, fails for large displacements of the object of interest. This paper presents a technique that incorporates the information on pixel velocities (optical flow) into the estimate of initial contour to enable tracking of fast-moving objects. The algorithm was tested on several ultrasound image sequences, each covering one complete cardiac cycle. The contour successfully tracked boundaries of mitral valve leaflets, aortic root and endocardial borders of the left ventricle. The algorithm-generated outlines were compared against manual tracings by expert physicians. The automated method resulted in contours that were within the boundaries of intraobserver variability.

Neighborhood environment profiles for physical activity among older adults.

PubMed

Adams, Marc A; Sallis, James F; Conway, Terry L; Frank, Lawrence D; Saelens, Brian E; Kerr, Jacqueline; Cain, Kelli L; King, Abby C

2012-11-01

To explore among older adults whether multivariate neighborhood profiles were associated with physical activity (PA) and BMI. Adults (66-97 years) were recruited from Baltimore-Washington, DC (n=360), and Seattle-King County, Washington (n=368), regions. Latent profile analyses were conducted using the Neighborhood Environment Walkability Scale. ANCOVA models tested for criterion validity of profiles by examining relationships to PA and BMI. Neighborhood profiles differed significantly by as much as 10 minutes/day for moderate-to-vigorous PA, 1.1 hours/week for walking for errands, and almost 50 minutes/week for leisure PA. Environmental variables resulted in meaningful neighborhood patterns that explained large differences in seniors' health outcomes.

Neighborhood influences on recreational physical activity and survival after breast cancer.

PubMed

Keegan, Theresa H M; Shariff-Marco, Salma; Sangaramoorthy, Meera; Koo, Jocelyn; Hertz, Andrew; Schupp, Clayton W; Yang, Juan; John, Esther M; Gomez, Scarlett L

2014-10-01

Higher levels of physical activity have been associated with improved survival after breast cancer diagnosis. However, no previous studies have considered the influence of the social and built environment on physical activity and survival among breast cancer patients. Our study included 4,345 women diagnosed with breast cancer (1995-2008) from two population-based studies conducted in the San Francisco Bay Area. We examined questionnaire-based moderate/strenuous recreational physical activity during the 3 years before diagnosis. Neighborhood characteristics were based on data from the 2000 US Census, business listings, parks, farmers' markets, and Department of Transportation. Survival was evaluated using multivariable Cox proportional hazards models, with follow-up through 2009. Women residing in neighborhoods with no fast-food restaurants (vs. fewer fast-food restaurants) to other restaurants, high traffic density, and a high percentage of foreign-born residents were less likely to meet physical activity recommendations set by the American Cancer Society. Women who were not recreationally physically active had a 22% higher risk of death from any cause than women that were the most active. Poorer overall survival was associated with lower neighborhood socioeconomic status (SES) (p(trend) = 0.02), whereas better breast cancer-specific survival was associated with a lack of parks, especially among women in high-SES neighborhoods. Certain aspects of the neighborhood have independent associations with recreational physical activity among breast cancer patients and their survival. Considering neighborhood factors may aide in the design of more effective, tailored physical activity programs for breast cancer survivors.

Neighborhood influences on recreational physical activity and survival after breast cancer

PubMed Central

Shariff-Marco, Salma; Sangaramoorthy, Meera; Koo, Jocelyn; Hertz, Andrew; Schupp, Clayton W.; Yang, Juan; John, Esther M.; Gomez, Scarlett L.

2014-01-01

Purpose Higher levels of physical activity have been associated with improved survival after breast cancer diagnosis. However, no previous studies have considered the influence of the social and built environment on physical activity and survival among breast cancer patients. Methods Our study included 4,345 women diagnosed with breast cancer (1995–2008) from two population-based studies conducted in the San Francisco Bay Area. We examined questionnaire-based moderate/strenuous recreational physical activity during the 3 years before diagnosis. Neighborhood characteristics were based on data from the 2000 US Census, business listings, parks, farmers’ markets, and Department of Transportation. Survival was evaluated using multivariable Cox proportional hazards models, with follow-up through 2009. Results Women residing in neighborhoods with no fast-food restaurants (vs. fewer fast-food restaurants) to other restaurants, high traffic density, and a high percentage of foreign-born residents were less likely to meet physical activity recommendations set by the American Cancer Society. Women who were not recreationally physically active had a 22 % higher risk of death from any cause than women that were the most active. Poorer overall survival was associated with lower neighborhood socioeconomic status (SES) (p trend = 0.02), whereas better breast cancer-specific survival was associated with a lack of parks, especially among women in high-SES neighborhoods. Conclusion Certain aspects of the neighborhood have independent associations with recreational physical activity among breast cancer patients and their survival. Considering neighborhood factors may aide in the design of more effective, tailored physical activity programs for breast cancer survivors. PMID:25088804

Neighborhood Design, Physical Activity, and Wellbeing: Applying the Walkability Model

PubMed Central

Zuniga-Teran, Adriana A.; Orr, Barron J.; Gimblett, Randy H.; Chalfoun, Nader V.; Guertin, David P.; Marsh, Stuart E.

2017-01-01

Neighborhood design affects lifestyle physical activity, and ultimately human wellbeing. There are, however, a limited number of studies that examine neighborhood design types. In this research, we examine four types of neighborhood designs: traditional development, suburban development, enclosed community, and cluster housing development, and assess their level of walkability and their effects on physical activity and wellbeing. We examine significant associations through a questionnaire (n = 486) distributed in Tucson, Arizona using the Walkability Model. Among the tested neighborhood design types, traditional development showed significant associations and the highest value for walkability, as well as for each of the two types of walking (recreation and transportation) representing physical activity. Suburban development showed significant associations and the highest mean values for mental health and wellbeing. Cluster housing showed significant associations and the highest mean value for social interactions with neighbors and for perceived safety from crime. Enclosed community did not obtain the highest means for any wellbeing benefit. The Walkability Model proved useful in identifying the walkability categories associated with physical activity and perceived crime. For example, the experience category was strongly and inversely associated with perceived crime. This study provides empirical evidence of the importance of including vegetation, particularly trees, throughout neighborhoods in order to increase physical activity and wellbeing. Likewise, the results suggest that regular maintenance is an important strategy to improve mental health and overall wellbeing in cities. PMID:28098785

Neighborhood Design, Physical Activity, and Wellbeing: Applying the Walkability Model.

PubMed

Zuniga-Teran, Adriana A; Orr, Barron J; Gimblett, Randy H; Chalfoun, Nader V; Guertin, David P; Marsh, Stuart E

2017-01-13

Neighborhood design affects lifestyle physical activity, and ultimately human wellbeing. There are, however, a limited number of studies that examine neighborhood design types. In this research, we examine four types of neighborhood designs: traditional development, suburban development, enclosed community, and cluster housing development, and assess their level of walkability and their effects on physical activity and wellbeing. We examine significant associations through a questionnaire ( n = 486) distributed in Tucson, Arizona using the Walkability Model. Among the tested neighborhood design types, traditional development showed significant associations and the highest value for walkability, as well as for each of the two types of walking (recreation and transportation) representing physical activity. Suburban development showed significant associations and the highest mean values for mental health and wellbeing. Cluster housing showed significant associations and the highest mean value for social interactions with neighbors and for perceived safety from crime. Enclosed community did not obtain the highest means for any wellbeing benefit. The Walkability Model proved useful in identifying the walkability categories associated with physical activity and perceived crime. For example, the experience category was strongly and inversely associated with perceived crime. This study provides empirical evidence of the importance of including vegetation, particularly trees, throughout neighborhoods in order to increase physical activity and wellbeing. Likewise, the results suggest that regular maintenance is an important strategy to improve mental health and overall wellbeing in cities.

Moving Beyond Neighborhood: Activity Spaces and Ecological Networks As Contexts for Youth Development

PubMed Central

Browning, Christopher R.; Soller, Brian

2014-01-01

Many scholars, policy analysts, and practitioners agree that neighborhoods are important contexts for urban youth. Yet, despite decades of research, our knowledge of why and how neighborhoods influence the day-to-day lives of youth is still emerging. Theories about neighborhood effects largely assume that neighborhoods operate to influence youth through exposure-based mechanisms. Extant theoretical approaches, however, have neglected the processes by which neighborhood socioeconomic contexts influence the routine spatial exposures—or activity spaces—of urban residents. In this article, we argue that exposure to organizations, institutions, and other settings that characterize individual activity spaces is a key mechanism through which neighborhoods influence youth outcomes. Moreover, we hypothesize that aggregate patterns of shared local exposure—captured by the concept of ecological networks—are influenced by neighborhood socioeconomic characteristics and are independently consequential for neighborhood youth. Neighborhoods in which residents intersect in space more extensively as a result of routine conventional activities will exhibit higher levels of social capital relevant to youth well-being, including (1) familiarity, (2) beneficial (weak) social ties, (3) trust, (4) shared expectations for pro-social youth behavior (collective efficacy), and (5) the capacity for consistent monitoring of public space. We then consider the implications of ecological networks for understanding the complexities of contextual exposure. We specifically discuss the role of embeddedness in ecological communities—that is, clusters of actors and locations that intersect at higher rates—for understanding contextual influences that are inadequately captured by geographically defined neighborhoods. We conclude with an overview of new approaches to data collection that incorporate insights from an activity-space and ecological-network perspective on neighborhood and

Conceptualizing and Comparing Neighborhood and Activity Space Measures for Food Environment Research

PubMed Central

Crawford, Thomas W.; Pitts, Stephanie B. Jilcott; McGuirt, Jared T.; Keyserling, Thomas C.; Ammerman, Alice S.

2014-01-01

Greater accessibility to geospatial technologies has led to a surge of spatialized public health research, much of which has focused on food environments. The purpose of this study was to analyze differing spatial measures of exposure to supermarkets and farmers’ markets among women of reproductive age in eastern North Carolina. Exposure measures were derived using participant-defined neighborhoods, investigator-defined road network neighborhoods, and activity spaces incorporating participants’ time space behaviors. Results showed that mean area for participant-defined neighborhoods (0.04 sq. miles) was much smaller than 2.0 mile road network neighborhoods (3.11 sq. miles) and activity spaces (26.36 sq. miles), and that activity spaces provided the greatest market exposure. The traditional residential neighborhood concept may not be particularly relevant for all places. Time-space approaches capturing activity space may be more relevant, particularly if integrated with mixed methods strategies. PMID:25306420

An improved active contour model for glacial lake extraction

NASA Astrophysics Data System (ADS)

Zhao, H.; Chen, F.; Zhang, M.

2017-12-01

Active contour model is a widely used method in visual tracking and image segmentation. Under the driven of objective function, the initial curve defined in active contour model will evolve to a stable condition - a desired result in given image. As a typical region-based active contour model, C-V model has a good effect on weak boundaries detection and anti noise ability which shows great potential in glacial lake extraction. Glacial lake is a sensitive indicator for reflecting global climate change, therefore accurate delineate glacial lake boundaries is essential to evaluate hydrologic environment and living environment. However, the current method in glacial lake extraction mainly contains water index method and recognition classification method are diffcult to directly applied in large scale glacial lake extraction due to the diversity of glacial lakes and masses impacted factors in the image, such as image noise, shadows, snow and ice, etc. Regarding the abovementioned advantanges of C-V model and diffcults in glacial lake extraction, we introduce the signed pressure force function to improve the C-V model for adapting to processing of glacial lake extraction. To inspect the effect of glacial lake extraction results, three typical glacial lake development sites were selected, include Altai mountains, Centre Himalayas, South-eastern Tibet, and Landsat8 OLI imagery was conducted as experiment data source, Google earth imagery as reference data for varifying the results. The experiment consequence suggests that improved active contour model we proposed can effectively discriminate the glacial lakes from complex backgound with a higher Kappa Coefficient - 0.895, especially in some small glacial lakes which belongs to weak information in the image. Our finding provide a new approach to improved accuracy under the condition of large proportion of small glacial lakes and the possibility for automated glacial lake mapping in large-scale area.

Human body contour data based activity recognition.

PubMed

Myagmarbayar, Nergui; Yuki, Yoshida; Imamoglu, Nevrez; Gonzalez, Jose; Otake, Mihoko; Yu, Wenwei

2013-01-01

This research work is aimed to develop autonomous bio-monitoring mobile robots, which are capable of tracking and measuring patients' motions, recognizing the patients' behavior based on observation data, and providing calling for medical personnel in emergency situations in home environment. The robots to be developed will bring about cost-effective, safe and easier at-home rehabilitation to most motor-function impaired patients (MIPs). In our previous research, a full framework was established towards this research goal. In this research, we aimed at improving the human activity recognition by using contour data of the tracked human subject extracted from the depth images as the signal source, instead of the lower limb joint angle data used in the previous research, which are more likely to be affected by the motion of the robot and human subjects. Several geometric parameters, such as, the ratio of height to weight of the tracked human subject, and distance (pixels) between centroid points of upper and lower parts of human body, were calculated from the contour data, and used as the features for the activity recognition. A Hidden Markov Model (HMM) is employed to classify different human activities from the features. Experimental results showed that the human activity recognition could be achieved with a high correct rate.

Preserving older adults' routine outdoor activities in contrasting neighborhood environments through a physical activity intervention

USDA-ARS?s Scientific Manuscript database

While neighborhood design can potentially influence routine outdoor physical activities (PA), little is known concerning its effects on such activities among older adults attempting to increase their PA levels. We evaluated the effects of living in neighborhoods differing in compactness on changes i...

[Association between the characteristics of the neighborhood environment and physical activity].

PubMed

Rodríguez-Romo, Gabriel; Garrido-Muñoz, María; Lucía, Alejandro; Mayorga, Juan I; Ruiz, Jonatan R

2013-01-01

To assess the relationship between the physical and social attributes of the neighborhood environment and levels of total physical activity (PA), leisure time PA, and active commuting PA in adults. The present cross-sectional study comprised 1500 adults (51.1% women) aged 15-74 years from the Autonomous Region of Madrid (Spain). Data were collected through a structured telephone interview. PA was assessed using the Global Physical Activity Questionnaire, version 2. Neighborhood attributes were assessed with the Environmental Module of the International Physical Activity Prevalence Study. The factors associated with a higher probability of achieving moderate to high levels of total PA and active commuting PA were living in high density residential areas, the presence of shops close to the residential area, public transport stops 10-15 minutes away from the home, and the existence of sidewalks in most of the neighborhood's streets (all p <0,05). The factors associated with moderate to high leisure time PA levels were the presence of active people in the residential area and the presence of low-cost recreational facilities (both p <0,05). Our findings suggest that most of the physical and social attributes of the neighborhood environment examined in this study are associated with total and active commuting PA, whereas only certain neighborhood attributes seem to be associated with leisure time PA. Copyright © 2012 SESPAS. Published by Elsevier Espana. All rights reserved.

Neighborhood walkability, income, and hour-by-hour physical activity patterns.

PubMed

Arvidsson, Daniel; Eriksson, Ulf; Lönn, Sara Larsson; Sundquist, Kristina

2013-04-01

This study aimed to investigate both the mean daily physical activity and the hour-by-hour physical activity patterns across the day using accelerometry and how they are associated with neighborhood walkability and individual income. Moderate physical activity (MPA) was assessed by accelerometry in 2252 adults in the city of Stockholm, Sweden. Neighborhood walkability (residential density, street connectivity, and land use mix) was objectively assessed within 1000m network buffers around the participants' residence and individual income was self-reported. Living in a high walkability neighborhood was associated with more mean daily MPA compared with living in a low walkability neighborhood on weekdays and weekend days. Hour-by-hour analyses showed that this association appeared mainly in the afternoon/early evening during weekdays, whereas it appeared across the middle of the day during weekend days. Individual income was associated with mean daily MPA on weekend days. On weekdays, the hour-by-hour analyses showed that high income was associated with more MPA around noon and in late afternoon/early evening, whereas low income was associated with more MPA at the hours before noon and in the early afternoon. During the weekend, high income was more consistently associated with higher MPA. Hour-by-hour accelerometry physical activity patterns provides a more comprehensive picture of the associations between neighborhood walkability and individual income and physical activity and the variability of these associations across the day.

Neighborhood Stress and Autonomic Nervous System Activity during Sleep.

PubMed

Mellman, Thomas Alan; Bell, Kimberly Ann; Abu-Bader, Soleman Hassan; Kobayashi, Ihori

2018-04-04

Stressful neighborhood environments are known to adversely impact health and contribute to health disparities but underlying mechanisms are not well understood. Healthy sleep can provide a respite from sustained sympathetic nervous system (SNS) activity. Our objective was to evaluate relationships between neighborhood stress and nocturnal and daytime SNS and parasympathetic nervous system (PNS) activity. Eighty five urban-residing African Americans (56.5% female; mean age of 23.0) participated. Evaluation included surveys of neighborhood stress and sleep-related vigilance; and continuous ECG and actigraphic recording in participants' homes from which heart rate variability (HRV) analysis for low frequency/high frequency (LF/HF) ratio and normalized high frequency (nHF), as indicators of SNS and PNS activity, respectively, and total sleep time (TST), and wake after sleep onset were derived. All significant relationships with HRV measures were from the sleep period. Neighborhood disorder correlated negatively with nHF (r = -.24, p = .035). There were also significant correlations of HRV indices with sleep duration and sleep fears. Among females, LF/HF correlated with exposure to violence, r = .39, p = .008 and nHF with census tract rates for violent crime (r = -.35, p = .035). In a stepwise regression, TST accounted for the variance contributed by violent crime to nHF in the female participants. Further investigation of relationships between neighborhood environments and SNS/PNS balance during sleep and their consequences, and strategies for mitigating such effects would have implications for health disparities.

Children's active free play in local neighborhoods: a behavioral mapping study.

PubMed

Veitch, J; Salmon, J; Ball, K

2008-10-01

Many Australian children are more sedentary than they should be, and almost one in five are currently overweight or obese. Some children may face difficulties finding opportunities to be active, having poor access to safe public open spaces or having low independent mobility limiting their access to places to play. This study aimed to examine children's access to places in their neighborhood for active free play and how these vary by age, sex and socioeconomic status (SES). Behavioral maps of the local neighborhood were completed by children (8-12 years) from five primary schools across different areas of Melbourne. Children living in low SES outer-urban neighborhoods had to travel greater distances to access local parks compared with those in inner-urban mid and high SES areas. One-third (32%) of children reported an independent mobility range of <100 m from home. In conclusion, for some children opportunities to engage in active free play in the local neighborhood may be limited due to lack of parks in close proximity to home and restricted independent mobility. It is important to collaborate with local governments, urban planners and community groups to improve access to neighborhood parks and to promote a sense of neighborhood safety.

The Neighborhood Energy Balance Equation: Does Neighborhood Food Retail Environment + Physical Activity Environment = Obesity? The CARDIA Study

PubMed Central

Boone-Heinonen, Janne; Diez-Roux, Ana V.; Goff, David C.; Loria, Catherine M.; Kiefe, Catarina I.; Popkin, Barry M.; Gordon-Larsen, Penny

2013-01-01

Background Recent obesity prevention initiatives focus on healthy neighborhood design, but most research examines neighborhood food retail and physical activity (PA) environments in isolation. We estimated joint, interactive, and cumulative impacts of neighborhood food retail and PA environment characteristics on body mass index (BMI) throughout early adulthood. Methods and Findings We used cohort data from the Coronary Artery Risk Development in Young Adults (CARDIA) Study [n=4,092; Year 7 (24-42 years, 1992-1993) followed over 5 exams through Year 25 (2010-2011); 12,921 person-exam observations], with linked time-varying geographic information system-derived neighborhood environment measures. Using regression with fixed effects for individuals, we modeled time-lagged BMI as a function of food and PA resource density (counts per population) and neighborhood development intensity (a composite density score). We controlled for neighborhood poverty, individual-level sociodemographics, and BMI in the prior exam; and included significant interactions between neighborhood measures and by sex. Using model coefficients, we simulated BMI reductions in response to single and combined neighborhood improvements. Simulated increase in supermarket density (from 25th to 75th percentile) predicted inter-exam reduction in BMI of 0.09 kg/m2 [estimate (95% CI): -0.09 (-0.16, -0.02)]. Increasing commercial PA facility density predicted BMI reductions up to 0.22 kg/m2 in men, with variation across other neighborhood features [estimate (95% CI) range: -0.14 (-0.29, 0.01) to -0.22 (-0.37, -0.08)]. Simultaneous increases in supermarket and commercial PA facility density predicted inter-exam BMI reductions up to 0.31 kg/m2 in men [estimate (95% CI) range: -0.23 (-0.39, -0.06) to -0.31 (-0.47, -0.15)] but not women. Reduced fast food restaurant and convenience store density and increased public PA facility density and neighborhood development intensity did not predict reductions in BMI

Multiple Active Contours Guided by Differential Evolution for Medical Image Segmentation

PubMed Central

Cruz-Aceves, I.; Avina-Cervantes, J. G.; Lopez-Hernandez, J. M.; Rostro-Gonzalez, H.; Garcia-Capulin, C. H.; Torres-Cisneros, M.; Guzman-Cabrera, R.

2013-01-01

This paper presents a new image segmentation method based on multiple active contours guided by differential evolution, called MACDE. The segmentation method uses differential evolution over a polar coordinate system to increase the exploration and exploitation capabilities regarding the classical active contour model. To evaluate the performance of the proposed method, a set of synthetic images with complex objects, Gaussian noise, and deep concavities is introduced. Subsequently, MACDE is applied on datasets of sequential computed tomography and magnetic resonance images which contain the human heart and the human left ventricle, respectively. Finally, to obtain a quantitative and qualitative evaluation of the medical image segmentations compared to regions outlined by experts, a set of distance and similarity metrics has been adopted. According to the experimental results, MACDE outperforms the classical active contour model and the interactive Tseng method in terms of efficiency and robustness for obtaining the optimal control points and attains a high accuracy segmentation. PMID:23983809

Associations between neighborhood socioeconomic environment and physical activity in Cuban immigrants.

PubMed

Affuso, Olivia; Singleton, Chelsea R; Brown, Scott C; Perrino, Tatiana; Huang, Shi; Szapocznik, José

2016-12-01

Physical inactivity is a major public health concern because it is a determinant of obesity and obesity-related chronic diseases. Few longitudinal studies have examined the association between neighborhood socioeconomic (SES) environment and change in physical activity behaviors. Additionally, few studies have examined this association in immigrant groups or Hispanic subgroups such as Cubans. This research aimed to determine if neighborhood SES is associated with longitudinal change in moderate-to-vigorous physical activity (MVPA) among Cuban immigrants who participate in the Cuban Health Study in Miami, Florida. Data on 280 participants [mean age: 37.4 (± 4.6), 48.9% women, mean body mass index: 25.0 (± 2.5)] collected at baseline, 12 months and 24 months were analyzed. Minutes of MVPA were objectively measured during each data collection period using accelerometers. A neighborhood SES score was calculated for each participant's residential census tract from American Community Survey data on median household income, median housing value, educational attainment and occupation. The neighborhood SES score was grouped into tertiles, reflecting low, moderate and high neighborhood SES environment. Multilevel linear models were used to examine the relationship between neighborhood SES and change in MVPA over 24 months. At baseline, 94 (33.6%), 108 (38.6%) and 78 (27.9%) participants resided in low, moderate, and high SES neighborhoods, respectively. After adjusting for age, sex, and body mass index, no difference in average change in MVPA over time was observed between participants residing in low and moderate SES neighborhoods ( p =0.48) or low and high SES neighborhoods ( p =0.62). In Cuban immigrants, longitudinal change in MVPA may not vary by neighborhood socioeconomic environment.

The associations of perceived neighborhood disorder and physical activity with obesity among African American adolescents.

PubMed

Dulin-Keita, Akilah; Kaur Thind, Herpreet; Affuso, Olivia; Baskin, Monica L

2013-05-04

According to recent research studies, the built and socioeconomic contexts of neighborhoods are associated with African American adolescents' participation in physical activity and obesity status. However, few research efforts have been devoted to understand how African American adolescents' perceptions of their neighborhood environments may affect physical activity behaviors and obesity status. The objective of the current study was to use a perceived neighborhood disorder conceptual framework to examine whether physical activity mediated the relationship between perceived neighborhood disorder and obesity status among African American adolescents. The data were obtained from a cross-sectional study that examined social and cultural barriers and facilitators of physical activity among African American adolescents. The study included a sample of 101 African American adolescents age 12 to 16 years and their parents who were recruited from the Birmingham, Alabama metropolitan area. The primary outcome measure was obesity status which was classified using the International Obesity Task Force cut off points. Moderate-to-vigorous physical activity was assessed via accelerometry. Perceived neighborhood disorder was assessed using the Perceived Neighborhood Disorder Scale. Mediation models were used to examine whether the relationship between neighborhood disorder and obesity status was mediated by physical activity. Perceived neighborhood disorder was significantly and positively related to obesity status and moderate-to-vigorous physical activity was inversely associated with obesity status. However, there was no evidence to support a significant mediating effect of moderate-to-vigorous physical activity on the relationship between neighborhood disorder and obesity status. Future studies should longitudinally assess perceived neighborhood disorder characteristics and childhood adiposity to examine the timing, extent, and the mechanisms by which perceived neighborhood

The First National Study of Neighborhood Parks: Implications for Physical Activity.

PubMed

Cohen, Deborah A; Han, Bing; Nagel, Catherine J; Harnik, Peter; McKenzie, Thomas L; Evenson, Kelly R; Marsh, Terry; Williamson, Stephanie; Vaughan, Christine; Katta, Sweatha

2016-10-01

An extensive infrastructure of neighborhood parks supports leisure time physical activity in most U.S. cities; yet, most Americans do not meet national guidelines for physical activity. Neighborhood parks have never been assessed nationally to identify their role in physical activity. Using a stratified multistage sampling strategy, a representative sample of 174 neighborhood parks in 25 major cities (population >100,000) across the U.S. was selected. Park use, park-based physical activity, and park conditions were observed during a typical week using systematic direct observation during spring/summer of 2014. Park administrators were interviewed to assess policies and practices. Data were analyzed in 2014-2015 using repeated-measure negative binomial regressions to estimate weekly park use and park-based physical activity. Nationwide, the average neighborhood park of 8.8 acres averaged 20 users/hour or an estimated 1,533 person hours of weekly use. Walking loops and gymnasia each generated 221 hours/week of moderate to vigorous physical activity. Seniors represented 4% of park users, but 20% of the general population. Parks were used less in low-income than in high-income neighborhoods, largely explained by fewer supervised activities and marketing/outreach efforts. Programming and marketing were associated with 37% and 63% more hours of moderate to vigorous physical activity/week in parks, respectively. The findings establish national benchmarks for park use, which can guide future park investments and management practices to improve population health. Offering more programming, using marketing tools like banners and posters, and installing facilities like walking loops, may help currently underutilized parks increase population physical activity. Copyright © 2016 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

Subjective neighborhood assessment and physical inactivity: An examination of neighborhood-level variance.

PubMed

Prochaska, John D; Buschmann, Robert N; Jupiter, Daniel; Mutambudzi, Miriam; Peek, M Kristen

2018-06-01

Research suggests a linkage between perceptions of neighborhood quality and the likelihood of engaging in leisure-time physical activity. Often in these studies, intra-neighborhood variance is viewed as something to be controlled for statistically. However, we hypothesized that intra-neighborhood variance in perceptions of neighborhood quality may be contextually relevant. We examined the relationship between intra-neighborhood variance of subjective neighborhood quality and neighborhood-level reported physical inactivity across 48 neighborhoods within a medium-sized city, Texas City, Texas using survey data from 2706 residents collected between 2004 and 2006. Neighborhoods where the aggregated perception of neighborhood quality was poor also had a larger proportion of residents reporting being physically inactive. However, higher degrees of disagreement among residents within neighborhoods about their neighborhood quality was significantly associated with a lower proportion of residents reporting being physically inactive (p=0.001). Our results suggest that intra-neighborhood variability may be contextually relevant in studies seeking to better understand the relationship between neighborhood quality and behaviors sensitive to neighborhood environments, like physical activity. Copyright © 2017 Elsevier Inc. All rights reserved.

An Alternative to Residential Neighborhoods: An Exploratory Study of how Activity Spaces and Perception of Neighborhood Social Processes relate to Maladaptive Parenting

PubMed Central

Freisthler, Bridget; Thomas, Crystal A.; Curry, Susanna R.; Wolf, Jennifer Price

2015-01-01

Background The environments where parents spend time, such as at work, at their child's school, or with friends and family, may exert a greater influence on their parenting behaviors than the residential neighborhoods where they live. These environments, termed activity spaces, provide individualized information about the where parents go, offering a more detailed understanding of the environmental risks and resources to which parents are exposed. Objective This study conducts a preliminary examination of how neighborhood context, social processes, and individual activity spaces are related to a variety of parenting practices. Methods Data were collected from 42 parents via door-to-door surveys in one neighborhood area. Survey participants provided information about punitive and non-punitive parenting practices, the locations where they conducted daily living activities, social supports, and neighborhood social processes. OLS regression procedures were used to examine covariates related to the size of parent activity spaces. Negative binomial models assessed how activity spaces were related to four punitive and five non-punitive parenting practices. Results With regards to size of parents' activity spaces, male caregivers and those with a local (within neighborhood) primary support member had larger activity spaces. Size of a parent's activity space is negatively related to use of punitive parenting, but generally not related to non-punitive parenting behaviors. Conclusions These findings suggest social workers should assess where parents spend their time and get socially isolated parents involved in activities that could result in less use of punitive parenting. PMID:27057130

On the Relationship between Variational Level Set-Based and SOM-Based Active Contours

PubMed Central

Abdelsamea, Mohammed M.; Gnecco, Giorgio; Gaber, Mohamed Medhat; Elyan, Eyad

2015-01-01

Most Active Contour Models (ACMs) deal with the image segmentation problem as a functional optimization problem, as they work on dividing an image into several regions by optimizing a suitable functional. Among ACMs, variational level set methods have been used to build an active contour with the aim of modeling arbitrarily complex shapes. Moreover, they can handle also topological changes of the contours. Self-Organizing Maps (SOMs) have attracted the attention of many computer vision scientists, particularly in modeling an active contour based on the idea of utilizing the prototypes (weights) of a SOM to control the evolution of the contour. SOM-based models have been proposed in general with the aim of exploiting the specific ability of SOMs to learn the edge-map information via their topology preservation property and overcoming some drawbacks of other ACMs, such as trapping into local minima of the image energy functional to be minimized in such models. In this survey, we illustrate the main concepts of variational level set-based ACMs, SOM-based ACMs, and their relationship and review in a comprehensive fashion the development of their state-of-the-art models from a machine learning perspective, with a focus on their strengths and weaknesses. PMID:25960736

Patterns of neighborhood environment attributes in relation to children's physical activity.

PubMed

Kurka, Jonathan M; Adams, Marc A; Todd, Michael; Colburn, Trina; Sallis, James F; Cain, Kelli L; Glanz, Karen; Frank, Lawrence D; Saelens, Brian E

2015-07-01

Characterizing neighborhood environments in relation to physical activity is complex. Latent profiles of parents' perceptions of neighborhood characteristics were examined in relation to accelerometer-measured moderate-to-vigorous physical activity (MVPA) among 678 children (ages 6-12) in two US regions. Neighborhood environment profiles derived from walkability, transit access, aesthetics, crime and traffic safety, pedestrian infrastructure, and recreation/park access were created for each region. The San Diego County profile lowest on walkability and recreation/park access was associated with an average of 13 fewer min/day of children's out-of-school MVPA compared to profiles higher on walkability and recreation/park access. Seattle/King County profiles did not differ on children's MVPA. Neighborhood environment profiles were associated with children's MVPA in one region, but results were inconsistent across regions. Copyright © 2015 Elsevier Ltd. All rights reserved.

Adolescent Physical Activity: Moderation of Individual Factors by Neighborhood Environment.

PubMed

D'Angelo, Heather; Fowler, Stephanie L; Nebeling, Linda C; Oh, April Y

2017-06-01

Less than a third of U.S. adolescents meet federal physical activity (PA) guidelines. Understanding correlates of PA at multiple levels of the Social Ecological Model could improve PA interventions among youth. This study examines (1) associations between factors across the Social Ecological Model including psychosocial factors, perceived neighborhood physical and social environment characteristics, and adolescent moderate to vigorous PA (MVPA) and (2) whether perceived neighborhood characteristics moderate associations between psychosocial factors and MVPA. A national sample of adolescents (aged 12-17 years) in the 2014 Family Life, Activity, Sun, Health, and Eating Study was used to examine associations between psychosocial characteristics, perceived neighborhood social and physical characteristics, and self-reported weekly minutes of MVPA. Analyses were conducted in 2015. Interaction terms between psychosocial and neighborhood variables were added to multiple linear regression models to examine moderation hypotheses. Significant two-way interactions revealed that neighborhoods with features perceived as supportive of PA strengthened several psychosocial-MVPA associations. The positive associations between MVPA and friend norms, friend support, and attitudes were strengthened for adolescents living in neighborhoods with high versus low PA resource availability (all p<0.05). Furthermore, the association between controlled and autonomous motivation and MVPA was strengthened under conditions of shops/stores near (versus distant from) adolescents' homes (p<0.05). The association between some psychosocial factors and adolescent MVPA may be environment dependent. Neighborhood physical and social environments supportive of PA are important to consider when developing targeted PA interventions and may strengthen the association between psychosocial-level factors and adolescent MVPA. Copyright © 2017 American Journal of Preventive Medicine. All rights reserved.

Preserving Older Adults’ Routine Outdoor Activities in Contrasting Neighborhood Environments through a Physical Activity Intervention

PubMed Central

King, Abby C.; Salvo, Deborah; Banda, Jorge A.; Ahn, David K.; Chapman, James E.; Gill, Thomas M.; Fielding, Roger A.; Demons, Jamehl; Tudor-Locke, Catrine; Rosso, Andrea; Pahor, Marco; Frank, Lawrence D.

2017-01-01

While neighborhood design can potentially influence routine outdoor physical activities (PA), little is known concerning its effects on such activities among older adults attempting to increase their PA levels. We evaluated the effects of living in neighborhoods differing in compactness on changes in routine outdoor activities (e.g., walking, gardening, yard work) among older adults at increased mobility disability risk participating in the LIFE-Pilot PA trial (2003–07; ages 70–89 years; from Dallas, TX, San Francisco Bay area, Pittsburgh, PA, and Winston-Salem, NC). Analyses were conducted on the 400 LIFE-Pilot participants randomized to a one-year endurance-plus-strengthening PA intervention or health education control that completed one-year PA assessment (CHAMPS questionnaire). Outcomes of interest were exercise and leisure walking, walking for errands, and moderate-intensity gardening. Neighborhood compactness was assessed objectively using geographic information systems via a subsequent grant (2008–12). PA increased weekly exercise and leisure walking relative to control, irrespective of neighborhood compactness. However, walking for errands decreased significantly more in PA relative to control (net mean[SD] difference=16.2 minutes/week[7.7], p=.037), particularly among those living in less compact neighborhoods (net mean[SD] difference=29.8[10.8] minutes/week, p=.006). PA participants living in less compact neighborhoods maintained or increased participation in gardening and yard work to a greater extent than controls (net mean[SD] difference=29.3[10.8] minutes/week, p=.007). The results indicate that formal targeting of active transport as an adjunct to structured PA programs may be important to diminish potential compensatory responses in functionally impaired older adults. Structured endurance-plus-strengthening PA may help older adults maintain or increase such routine activities over time. Trial Registration clinicaltrials.gov Identifier= NCT

Active Transportation in Adult Survivors of Childhood Cancer and Neighborhood Controls

PubMed Central

Slater, Megan E.; Kelly, Aaron S.; Sadak, Karim T.; Ross, Julie A.

2015-01-01

Purpose Childhood cancer survivors (CCS) are at high risk of treatment-related late effects, including cardiovascular disease and diabetes, which can be exacerbated by inadequate physical activity (PA). Previous PA interventions targeting CCS have focused on the domain of leisure-time/recreational PA. Active transportation, another domain of PA, has not been described in CCS. Therefore, this study aimed to identify active transportation behaviors, barriers, and correlates in adult CCS. Methods We recruited 158 adult CCS and 153 controls matched on age, sex, and neighborhood for a survey regarding active transportation behaviors and perceptions. Linear and logistic regression models accounting for correlation among matched participants were used. Results Adult CCS engaged in similar levels of active transportation as controls (2.72 vs. 2.32 hours/week, P=0.40) despite perceiving greater health-related barriers (1.88 vs. 1.65 (measured on four-point Likert scale), P=0.01). Marital/relationship status (odds ratio (OR)=0.30, 95% confidence interval (CI)=0.11–0.81), planning/psychosocial barriers (OR=0.15, 95% CI=0.04–0.53), and perceived neighborhood walkability (OR=2.55, 95% CI=1.14–5.66) were correlates of active transportation among adult CCS, while objective neighborhood walkability (OR=1.03, 95% CI=1.01–1.05) was a correlate among controls. Conclusions Results suggest adult CCS and controls utilize active transportation at approximately equal levels. Factors other than health, including perceived neighborhood walkability, appear to influence active transportation behaviors to a greater degree in adult CCS. Implications for Cancer Survivors Interventions might consider promoting active transportation as a way to incorporate more PA into the daily lives of adult CCS. Such interventions will not be widely successful, however, without existing or improved neighborhood walkability/bikeability. PMID:25809159

Active transportation in adult survivors of childhood cancer and neighborhood controls.

PubMed

Slater, Megan E; Kelly, Aaron S; Sadak, Karim T; Ross, Julie A

2016-02-01

Childhood cancer survivors (CCS) are at high risk of treatment-related late effects, including cardiovascular disease and diabetes, which can be exacerbated by inadequate physical activity (PA). Previous PA interventions targeting CCS have focused on the domain of leisure-time/recreational PA. Active transportation, another domain of PA, has not been described in CCS. Therefore, this study aimed to identify active transportation behaviors, barriers, and correlates in adult CCS. We recruited 158 adult CCS and 153 controls matched on age, sex, and neighborhood for a survey regarding active transportation behaviors and perceptions. Linear and logistic regression models accounting for correlation among matched participants were used. Adult CCS engaged in similar levels of active transportation as controls (2.72 vs. 2.32 h/week, P = 0.40) despite perceiving greater health-related barriers (1.88 vs. 1.65 (measured on four-point Likert scale), P = 0.01). Marital/relationship status (odds ratio (OR) = 0.30, 95 % confidence interval (CI) = 0.11-0.81), planning/psychosocial barriers (OR = 0.15, 95 % CI = 0.04-0.53), and perceived neighborhood walkability (OR = 2.55, 95 % CI = 1.14-5.66) were correlates of active transportation among adult CCS, while objective neighborhood walkability (OR = 1.03, 95 % CI = 1.01-1.05) was a correlate among controls. Results suggest adult CCS and controls utilize active transportation at approximately equal levels. Factors other than health, including perceived neighborhood walkability, are related to active transportation behaviors to a greater degree in adult CCS. Interventions might consider promoting active transportation as a way to incorporate more PA into the daily lives of adult CCS. Such interventions will not be likely successful, however, without existing or improved neighborhood walkability/bikeability.

The impact of neighborhood on physical activity in the Jackson Heart Study.

PubMed

Robinson, Jennifer C; Wyatt, Sharon B; Dubbert, Patricia M; May, Warren; Sims, Mario

2016-09-01

Physical inactivity is an independent risk factor for many diseases. Most research has focused on individual-level factors for physical activity (PA), but evidence suggests that neighborhood is also important. We examined baseline data collected between 2000 and 2004 from 5236 participants in the Jackson Heart Study to determine the effects of neighborhood on 2 types of PA: Active Living (AL), and Sports and Exercise (Sport) in an all-African American cohort. Participants were georeferenced and data from individual baseline questionnaires and US Census were analyzed using descriptive, bivariate, and multilevel models. In both types of PA, neighborhood factors had an independent and additive effect on AL and Sport. Living in an urban (p=0.003) or neighborhood with a higher percentage of residents with less than a high school education (p<0.001) was inversely associated with AL. There was an inverse interaction effect between individual and lower neighborhood education (p=0.01), as well as between age and urban neighborhoods (p=0.02) on AL. Individual level education (OR=1.30) and per capita income (OR=1.07) increased the odds of moderate-to-high sports. Future studies should focus on what contextual aspects of urban or less educated neighborhoods are influential in determining PA, as well as longitudinal multilevel analyses of neighborhood effects on PA. Copyright © 2016 Elsevier Inc. All rights reserved.

Neighborhood perceptions and active school commuting in low-income cities.

PubMed

Deweese, Robin S; Yedidia, Michael J; Tulloch, David L; Ohri-Vachaspati, Punam

2013-10-01

Few children accumulate the recommended ≥60 minutes of physical activity each day. Active travel to and from school (ATS) is a potential source of increased activity for children, accounting for 22% of total trips and time spent traveling by school-aged children. This study identifies the association of parents' perceptions of the neighborhood, geospatial variables, and demographic characteristics with ATS among students in four low-income, densely populated urban communities with predominantly minority populations. Data were collected in 2009-2010 from households with school-attending children in four low-income New Jersey cities. Multivariate logistic regression analyses (n=765) identified predictors of ATS. Analyses were conducted in 2012. In all, 54% of students actively commuted to school. Students whose parents perceived the neighborhood as very unpleasant for activity were less likely (OR=0.39) to actively commute, as were students living farther from school, with a 6% reduction in ATS for every 0.10 mile increase in distance to school. Perceptions of crime, traffic, and sidewalk conditions were not predictors of ATS. Parents' perceptions of the pleasantness of the neighborhood, independent of the effects of distance from school, may outweigh concerns about crime, traffic, or conditions of sidewalks in predicting active commuting to school in the low-income urban communities studied. Efforts such as cleaning up graffiti, taking care of abandoned buildings, and providing shade trees to improve neighborhood environments are likely to increase ATS, as are efforts that encourage locating schools closer to the populations they serve. © 2013 American Journal of Preventive Medicine.

Segmentation of breast ultrasound images based on active contours using neutrosophic theory.

PubMed

Lotfollahi, Mahsa; Gity, Masoumeh; Ye, Jing Yong; Mahlooji Far, A

2018-04-01

Ultrasound imaging is an effective approach for diagnosing breast cancer, but it is highly operator-dependent. Recent advances in computer-aided diagnosis have suggested that it can assist physicians in diagnosis. Definition of the region of interest before computer analysis is still needed. Since manual outlining of the tumor contour is tedious and time-consuming for a physician, developing an automatic segmentation method is important for clinical application. The present paper represents a novel method to segment breast ultrasound images. It utilizes a combination of region-based active contour and neutrosophic theory to overcome the natural properties of ultrasound images including speckle noise and tissue-related textures. First, due to inherent speckle noise and low contrast of these images, we have utilized a non-local means filter and fuzzy logic method for denoising and image enhancement, respectively. This paper presents an improved weighted region-scalable active contour to segment breast ultrasound images using a new feature derived from neutrosophic theory. This method has been applied to 36 breast ultrasound images. It generates true-positive and false-positive results, and similarity of 95%, 6%, and 90%, respectively. The purposed method indicates clear advantages over other conventional methods of active contour segmentation, i.e., region-scalable fitting energy and weighted region-scalable fitting energy.

Neighborhoods on the move: a community-based participatory research approach to promoting physical activity.

PubMed

Suminski, Richard R; Petosa, Rick L; Jones, Larry; Hall, Lisa; Poston, Carlos W

2009-01-01

There is a scientific and practical need for high-quality effectiveness studies of physical activity interventions in "real-world" settings. To use a community-based participatory research (CBPR) approach to develop, implement, operate, and evaluate an intervention for promoting physical activity called Neighborhoods on the Move. Two communities with similar physical and social characteristics participated in this study. One community was involved in Neighborhoods on the Move; the other (comparison community) participated only in the assessments. Academic personnel and residents/organizations in the Neighborhoods on the Move community worked together to create a community environment that was more conducive for physical activity. Pre- and posttest data on new initiatives promoting physical activity, existing physical activity initiatives, and business policies supporting physical activity were collected simultaneously in both communities. The success of the CBPR approach was evidenced by several developments, including substantial resident involvement and the formation of a leadership committee, marketing campaign, and numerous community partnerships. The number of businesses with policies promoting physical activity and breadth of existing physical activity initiatives (participants, activities, hours) increased substantially more in the Neighborhoods on the Move community than in the comparison community. A total of sixty new initiatives promoting physical activity were implemented in the Neighborhoods on the Move community during the intervention. The CBPR approach is an effective strategy for inducing environmental changes that promote physical activity. Additional research is needed to assess the portability and sustainability of Neighborhoods on the Move.

Neighborhood Jams.

ERIC Educational Resources Information Center

Zingher, Gary

1995-01-01

Examines the role of the neighborhood in books for children and young adults. Discusses community characteristics, historical fiction, "special and scary places," neighborhoods in conflict and harmony, and the neighborhood as a memory base. Presents activities including animated maps, games, murals, small group dramas, and storytelling.…

Active contours on statistical manifolds and texture segmentation

Treesearch

Sang-Mook Lee; A. Lynn Abbott; Neil A. Clark; Philip A. Araman

2005-01-01

A new approach to active contours on statistical manifolds is presented. The statistical manifolds are 2- dimensional Riemannian manifolds that are statistically defined by maps that transform a parameter domain onto a set of probability density functions. In this novel framework, color or texture features are measured at each image point and their statistical...

Active contours on statistical manifolds and texture segmentaiton

Treesearch

Sang-Mook Lee; A. Lynn Abbott; Neil A. Clark; Philip A. Araman

2005-01-01

A new approach to active contours on statistical manifolds is presented. The statistical manifolds are 2- dimensional Riemannian manifolds that are statistically defined by maps that transform a parameter domain onto-a set of probability density functions. In this novel framework, color or texture features are measured at each Image point and their statistical...

Perceptions of the Neighborhood Environment and Children's Afterschool Moderate-to-Vigorous Physical Activity.

PubMed

McDonald, Samantha; Dowda, Marsha; Colabianchi, Natalie; Porter, Dwayne; Dishman, Rod K; Pate, Russell R

2015-05-01

Previous research suggests the neighborhood environment may be an important influence on children's physical activity (PA) behaviors; however, findings are inconsistent. The purpose of this study was to further understand the relationship between perceptions of the neighborhood environment and children's afterschool moderate-to-vigorous PA. Utilizing a structural equation modeling technique, we tested a conceptual model linking parent and child perceptions of the neighborhood environment, parent support for PA, and child outdoor PA with children's afterschool moderate-to vigorous PA. We found that child perception of the neighborhood environment and outdoor PA were positively associated with afterschool moderate-to-vigorous PA. In addition, parent support for PA positively influenced children's outdoor PA. The neighborhood environment and outdoor activity appear to play an influential role on children's afterschool PA behaviors.

Where they live, how they play: Neighborhood greenness and outdoor physical activity among preschoolers

PubMed Central

2011-01-01

Background Emerging empirical evidence suggests exposure to "green" environments may encourage higher levels of physical activity among children. Few studies, however, have explored this association exclusively in pre-school aged children in the United States. We examined whether residing in neighborhoods with higher levels of greenness was associated with higher levels of outdoor physical activity among preschoolers. In addition, we also explored whether outdoor playing behaviors (e.g., active vs. quiet) were influenced by levels of neighborhood greenness independent of demographic and parental support factors. Results Higher levels of neighborhood greenness as measured by the Normalized Difference Vegetation Index (NDVI) was associated with higher levels of outdoor playing time among preschool-aged children in our sample. Specifically, a one unit increase in neighborhood greenness increased a child's outdoor playing time by approximately 3 minutes. A dose-response relationship was observed between increasing levels of parental support for physical activity (e.g., time spent playing with children) and child outdoor physical activity (p < 0.01). Conclusions Consistent with previous studies, neighborhood greenness influences physical activity behavior. However, for preschoolers, parental involvement may be more critical for improving physical activity levels. PMID:22165919

Method for non-referential defect characterization using fractal encoding and active contours

DOEpatents

Gleason, Shaun S [Knoxville, TN; Sari-Sarraf, Hamed [Lubbock, TX

2007-05-15

A method for identification of anomalous structures, such as defects, includes the steps of providing a digital image and applying fractal encoding to identify a location of at least one anomalous portion of the image. The method does not require a reference image to identify the location of the anomalous portion. The method can further include the step of initializing an active contour based on the location information obtained from the fractal encoding step and deforming an active contour to enhance the boundary delineation of the anomalous portion.

Does perceived neighborhood walkability and safety mediate the association between education and meeting physical activity guidelines?

PubMed

Pratt, Michael; Yin, Shaoman; Soler, Robin; Njai, Rashid; Siegel, Paul Z; Liao, Youlian

2015-04-09

The role of neighborhood walkability and safety in mediating the association between education and physical activity has not been quantified. We used data from the 2010 and 2012 Communities Putting Prevention to Work Behavioral Risk Factor Surveillance System and structural equation modeling to estimate how much of the effect of education level on physical activity was mediated by perceived neighborhood walkability and safety. Neighborhood walkability accounts for 11.3% and neighborhood safety accounts for 6.8% of the effect. A modest proportion of the important association between education and physical activity is mediated by perceived neighborhood walkability and safety, suggesting that interventions focused on enhancing walkability and safety could reduce the disparity in physical activity associated with education level.

Parental Perceptions of the Social Environment Are Inversely Related to Constraint of Adolescents’ Neighborhood Physical Activity

PubMed Central

Kepper, Maura; Broyles, Stephanie; Scribner, Richard; Tseng, Tung-Sung; Zabaleta, Jovanny; Griffiths, Lauren; Sothern, Melinda

2016-01-01

Background: The current study examined relationships between the neighborhood social environment (parental perceived collective efficacy (PCE)), constrained behaviors (e.g., avoidance or defensive behaviors) and adolescent offspring neighborhood physical activity in low- versus high-incivility neighborhoods. Methods: Adolescents (n = 71; 11–18 years (14.2, SD ± 1.6); male = 37 (52%); non-white = 24 (33.8%); low-income = 20 (29%); overweight/obese = 40 (56%)) and their parents/guardians enrolled in the Molecular and Social Determinants of Obesity in Developing Youth study were included in the current study. Questionnaires measured parents’/guardians’ PCE, constrained outdoor play practices and offspring neighborhood physical activity. Systematic social observation performed at the parcel-level using Google Street View assessed neighborhood incivilities. t-tests and chi-square tests determined differences by incivilities. Multilevel regression models examined relationships between PCE and: (1) constrained behaviors; and (2) neighborhood physical activity. The Hayes (2013) macro determined the mediating role of constrained behaviors. Results: Parents who had higher PCE reported lower levels of avoidance (p = 0.04) and defensive (p = 0.05) behaviors. However, demographic variables (i.e., gender, race and annual household income) limited these results. The direct relationship between PCE and parent-reported neighborhood physical activity was statistically significant in high-incivility neighborhoods only. Neither avoidance nor defensive behavior mediated the relationship between PCE and neighborhood physical activity. Conclusions: PCE influences parenting behaviors related to youth physical activity. Community-based programs that seek to facilitate social cohesion and control may be needed to increase adolescents’ physical activity. PMID:28009839

Joint classification and contour extraction of large 3D point clouds

NASA Astrophysics Data System (ADS)

Hackel, Timo; Wegner, Jan D.; Schindler, Konrad

2017-08-01

We present an effective and efficient method for point-wise semantic classification and extraction of object contours of large-scale 3D point clouds. What makes point cloud interpretation challenging is the sheer size of several millions of points per scan and the non-grid, sparse, and uneven distribution of points. Standard image processing tools like texture filters, for example, cannot handle such data efficiently, which calls for dedicated point cloud labeling methods. It turns out that one of the major drivers for efficient computation and handling of strong variations in point density, is a careful formulation of per-point neighborhoods at multiple scales. This allows, both, to define an expressive feature set and to extract topologically meaningful object contours. Semantic classification and contour extraction are interlaced problems. Point-wise semantic classification enables extracting a meaningful candidate set of contour points while contours help generating a rich feature representation that benefits point-wise classification. These methods are tailored to have fast run time and small memory footprint for processing large-scale, unstructured, and inhomogeneous point clouds, while still achieving high classification accuracy. We evaluate our methods on the semantic3d.net benchmark for terrestrial laser scans with >109 points.

Safe To Walk? Neighborhood Safety and Physical Activity Among Public Housing Residents

PubMed Central

Bennett, Gary G; McNeill, Lorna H; Wolin, Kathleen Y; Duncan, Dustin T; Puleo, Elaine; Emmons, Karen M

2007-01-01

Background Despite its health benefits, physical inactivity is pervasive, particularly among those living in lower-income urban communities. In such settings, neighborhood safety may impact willingness to be regularly physically active. We examined the association of perceived neighborhood safety with pedometer-determined physical activity and physical activity self-efficacy. Methods and Findings Participants were 1,180 predominantly racial/ethnic minority adults recruited from 12 urban low-income housing complexes in metropolitan Boston. Participants completed a 5-d pedometer data-collection protocol and self-reported their perceptions of neighborhood safety and self-efficacy (i.e., confidence in the ability to be physically active). Gender-stratified bivariate and multivariable random effects models were estimated to account for within-site clustering. Most participants reported feeling safe during the day, while just over one-third (36%) felt safe at night. We found no association between daytime safety reports and physical activity among both men and women. There was also no association between night-time safety reports and physical activity among men (p = 0.23) but women who reported feeling unsafe (versus safe) at night showed significantly fewer steps per day (4,302 versus 5,178, p = 0.01). Perceiving one's neighborhood as unsafe during the day was associated with significantly lower odds of having high physical activity self-efficacy among both men (OR 0.40, p = 0.01) and women (OR 0.68, p = 0.02). Conclusions Residing in a neighborhood that is perceived to be unsafe at night is a barrier to regular physical activity among individuals, especially women, living in urban low-income housing. Feeling unsafe may also diminish confidence in the ability to be more physically active. Both of these factors may limit the effectiveness of physical activity promotion strategies delivered in similar settings. PMID:17958465

The role of neighborhood economic context on physical activity among children: Evidence from the Geographic Research on Wellbeing (GROW) study.

PubMed

Kim, Yeonwoo; Cubbin, Catherine

2017-08-01

Less than half of young children in the U.S. meet physical activity recommendations. While neighborhood economic context has been shown to be associated with physical activity, it is unknown whether this association varies according to family economic context. This study thus investigates whether neighborhood economic context, measured by poverty concentration and income inequality, are associated with physical activity among poor and non-poor children using data from the Geographic Research on Wellbeing study, California, 2012-2013 (N=2670). Poor children who resided in (a) poor and equal neighborhoods or (b) non-poor and equal neighborhoods were more likely to engage in sufficient physical activity than were children residing in non-poor and unequal neighborhoods. Poor children in (a) non-poor and equal neighborhoods, (b) poor and equal neighborhoods, or (c) poor and unequal neighborhoods were less likely to report insufficient physical activity than those in non-poor and unequal neighborhoods. Neighborhood economic context was not associated with physical activity among non-poor children. Findings suggest that neighborhood economic context presents a social barrier to physical activity among poor children. Increasing physical activity among poor children in non-poor and unequal neighborhoods should be a high policy priority. Perceived social cohesion, perceived neighborhood safety, and park and walkability indicators did not mediate the associations between neighborhood economic context and physical activity. Further research needs to explore the mechanisms by which neighborhood economic context affects physical activity among children. Copyright © 2017 Elsevier Inc. All rights reserved.

Residential Neighborhood Amenities and Physical Activity Among U.S. Children with Special Health Care Needs.

PubMed

An, Ruopeng; Yang, Yan; Li, Kaigang

2017-05-01

Objectives Children with special health care needs (SHCN) have or are at elevated risk for chronic physical, developmental, behavioral or emotional conditions and therefore require specialized health care services. This study examines the relationship between residential neighborhood amenities and physical activity among U.S. children with SHCN. Methods A nationally representative sample of 113,767 children aged 6-17 years was taken from National Survey of Children's Health (NSCH) 2007-2008 and 2011-2012. Residential neighborhood amenities were defined by parent-reported presence or absence of sidewalks, parks/playgrounds, and recreation center. Physical activity was measured by parent-reported number of physically active days (0-7), defined as 20 min or longer during the past week. Negative binomial regressions were performed to estimate the associations between residential neighborhood amenities and physical activity among U.S. children with and without SHCN, adjusting for various neighborhood (detracting condition and safety) and individual characteristics and NSCH sampling design. Results Approximately 23% of young children aged 6-11 years and adolescents aged 12-17 years had SHCN. Number of weekly physically active days was both 4.8 among young children with and without SHCN, and 3.7 and 4.1 among adolescents with and without SHCN, respectively. Among young children with SHCN, neighborhood availability of a recreation center was associated with increased weekly physically active days by 0.23; whereas among young children without SHCN, number of weekly physically active days was not associated with the availability of any amenity. Among adolescents with SHCN, neighborhood availability of parks/playgrounds was associated with increased weekly physically active days by 0.33, whereas neighborhood availability of sidewalks was associated with reduced weekly physically active days by 0.21. Conversely, among adolescents without SHCN, neighborhood availability of a

A novel content-based active contour model for brain tumor segmentation.

PubMed

Sachdeva, Jainy; Kumar, Vinod; Gupta, Indra; Khandelwal, Niranjan; Ahuja, Chirag Kamal

2012-06-01

Brain tumor segmentation is a crucial step in surgical and treatment planning. Intensity-based active contour models such as gradient vector flow (GVF), magneto static active contour (MAC) and fluid vector flow (FVF) have been proposed to segment homogeneous objects/tumors in medical images. In this study, extensive experiments are done to analyze the performance of intensity-based techniques for homogeneous tumors on brain magnetic resonance (MR) images. The analysis shows that the state-of-art methods fail to segment homogeneous tumors against similar background or when these tumors show partial diversity toward the background. They also have preconvergence problem in case of false edges/saddle points. However, the presence of weak edges and diffused edges (due to edema around the tumor) leads to oversegmentation by intensity-based techniques. Therefore, the proposed method content-based active contour (CBAC) uses both intensity and texture information present within the active contour to overcome above-stated problems capturing large range in an image. It also proposes a novel use of Gray-Level Co-occurrence Matrix to define texture space for tumor segmentation. The effectiveness of this method is tested on two different real data sets (55 patients - more than 600 images) containing five different types of homogeneous, heterogeneous, diffused tumors and synthetic images (non-MR benchmark images). Remarkable results are obtained in segmenting homogeneous tumors of uniform intensity, complex content heterogeneous, diffused tumors on MR images (T1-weighted, postcontrast T1-weighted and T2-weighted) and synthetic images (non-MR benchmark images of varying intensity, texture, noise content and false edges). Further, tumor volume is efficiently extracted from 2-dimensional slices and is named as 2.5-dimensional segmentation. Copyright © 2012 Elsevier Inc. All rights reserved.

The Influence of Neighborhood Crime on Increases in Physical Activity during a Pilot Physical Activity Intervention in Children.

PubMed

Broyles, Stephanie T; Myers, Candice A; Drazba, Kathryn T; Marker, Arwen M; Church, Timothy S; Newton, Robert L

2016-04-01

The purpose of this study was to examine whether neighborhood crime moderated the response (increases in steps) to a pilot intervention to increase physical activity in children. Twenty-seven insufficiently active children aged 6-10 years (mean age = 8.7 years; 56 % female; 59 % African American) were randomly assigned to an intensive intervention group (IIG) or minimal intervention group (MIG). Change in average daily number of steps from baseline was regressed against an index of neighborhood crime in a multilevel repeated-measures model that included a propensity score to reduce confounding. Safer neighborhoods were associated with higher increases in steps during the pilot intervention (interaction p = 0.008). Children in the IIG living in low-crime neighborhoods significantly increased their physical activity (5275 ± 1040 steps/day) while those living in high-crime neighborhoods did not (1118 ± 1007) (p for difference = 0.046). In the IIG, the increase in daily steps was highly correlated with neighborhood crime (r = 0.58, p = 0.04). These findings suggest the need for physical activity interventions to account for participants' environments in their design and/or delivery. To promote healthy behaviors in less-supportive environments, future studies should seek to understand how environments modify intervention response and to identify mediators of the relationship between environment and intervention.

Does Perceived Neighborhood Walkability and Safety Mediate the Association Between Education and Meeting Physical Activity Guidelines?

PubMed Central

Yin, Shaoman; Soler, Robin; Njai, Rashid; Siegel, Paul Z.; Liao, Youlian

2015-01-01

The role of neighborhood walkability and safety in mediating the association between education and physical activity has not been quantified. We used data from the 2010 and 2012 Communities Putting Prevention to Work Behavioral Risk Factor Surveillance System and structural equation modeling to estimate how much of the effect of education level on physical activity was mediated by perceived neighborhood walkability and safety. Neighborhood walkability accounts for 11.3% and neighborhood safety accounts for 6.8% of the effect. A modest proportion of the important association between education and physical activity is mediated by perceived neighborhood walkability and safety, suggesting that interventions focused on enhancing walkability and safety could reduce the disparity in physical activity associated with education level. PMID:25855989

Promoting Active Urban Aging: A Measurement Approach to Neighborhood Walkability for Older Adults

PubMed Central

Weiss, Rachael L.; Maantay, Juliana A.; Fahs, Marianne

2011-01-01

Understanding the role of the built environment on physical activity behavior among older adults is an important public health goal, but evaluating these relationships remains complicated due to the difficulty of measuring specific attributes of the environment. As a result, there is conflicting evidence regarding the association between perceived and objectively measured walkability and physical activity among urban-dwelling older adults. This suggests that both actual environmental features and perceptions of these attributes influence walking behavior. The purpose of this pilot project is to create an Objective Walkability Index (OWI) by census block using a Geographic Information System (GIS) and supplement the results with resident perceptions thus more accurately characterizing the context of walkability. Computerized Neighborhood Environment Tracking (ComNET) was used to systematically assess environmental risks impacting activity patterns of older adults in two New York City neighborhoods. In addition, the Senior Center Evaluation of the Neighborhood Environment (SCENE) survey was administered to older adults attending two senior centers located within the target neighborhoods. The results indicate that there is substantial variation in OWI score both between and within the neighborhoods suggesting that residence in some communities may increase the risk of inactivity among older adults. Also, low walkability census blocks were clustered within each neighborhood providing an opportunity for targeted investigation into localized threats to walkability. A lack of consensus regarding the association between the built environment and physical activity among older adults is a consequence of the problems inherent in measuring these determinants. Further empirical evidence evaluating the complex relationships between the built environment and physical activity is an essential step towards creating active communities. PMID:21874149

Redefining Neighborhoods Using Common Destinations: Social Characteristics of Activity Spaces and Home Census Tracts Compared

PubMed Central

Jones, Malia; Pebley, Anne R.

2014-01-01

Research on neighborhood effects has focused largely on residential neighborhoods, but people are exposed to many other places in the course of their daily lives—at school, at work, when shopping, and so on. Thus, studies of residential neighborhoods consider only a subset of the social-spatial environment affecting individuals. In this article, we examine the characteristics of adults’ “activity spaces”—spaces defined by locations that individuals visit regularly, in Los Angeles County, California. Using geographic information system (GIS) methods, we define activity spaces in two ways and estimate their socioeconomic characteristics. Our research has two goals. First, we determine whether residential neighborhoods represent the social conditions to which adults are exposed in the course of their regular activities. Second, we evaluate whether particular groups are exposed to a broader or narrower range of social contexts in the course of their daily activities. We find that activity spaces are substantially more heterogeneous in terms of key social characteristics, compared to residential neighborhoods. However, the characteristics of both home neighborhoods and activity spaces are closely associated with individual characteristics. Our results suggest that most people experience substantial segregation across the range of spaces in their daily lives, not just at home. PMID:24719273

Redefining neighborhoods using common destinations: social characteristics of activity spaces and home census tracts compared.

PubMed

Jones, Malia; Pebley, Anne R

2014-06-01

Research on neighborhood effects has focused largely on residential neighborhoods, but people are exposed to many other places in the course of their daily lives-at school, at work, when shopping, and so on. Thus, studies of residential neighborhoods consider only a subset of the social-spatial environment affecting individuals. In this article, we examine the characteristics of adults' "activity spaces"-spaces defined by locations that individuals visit regularly-in Los Angeles County, California. Using geographic information system (GIS) methods, we define activity spaces in two ways and estimate their socioeconomic characteristics. Our research has two goals. First, we determine whether residential neighborhoods represent the social conditions to which adults are exposed in the course of their regular activities. Second, we evaluate whether particular groups are exposed to a broader or narrower range of social contexts in the course of their daily activities. We find that activity spaces are substantially more heterogeneous in terms of key social characteristics, compared to residential neighborhoods. However, the characteristics of both home neighborhoods and activity spaces are closely associated with individual characteristics. Our results suggest that most people experience substantial segregation across the range of spaces in their daily lives, not just at home.

Neighborhood contextual characteristics and leisure-time physical activity: Pró-Saúde Study.

PubMed

Boclin, Karine de Lima Sírio; Faerstein, Eduardo; Leon, Antônio Carlos Monteiro Ponce de

2014-04-01

To estimate the association between neighborhood contextual variables and leisure-time physical activity. Data were analyzed for 2,674 adults from Rio de Janeiro, RJ, Southeastern Brazil, participating in the longitudinal study in 1999. Leisure-time physical activity in the two preceding weeks was assessed dichotomously. Sex, age, income, education and marital status were analyzed as individual variables. Neighborhood contextual characteristics were the social development index, the Theil index and the proportion of the area occupied by parks, squares and gardens, categorized in quintiles. The unadjusted and adjusted odds ratios and 95% confidence intervals were estimated using multilevel logistic regression. The prevalence of leisure-time physical activity was higher in residents in neighborhoods with higher indices of social development (between 32.3% and 53.1%) and a greater proportion of parks, squares and gardens (between 35.8% and 53.1%). Regarding the social development index, the adjusted odds ratios for physical activity were 1.22 (95%CI 0.93;1.61), 1.44 (95%CI 1.09;1.89), 1.75 (95%CI 1.31;2.34) and 2.25 (95%CI 1.70;3.00) for residents in neighborhoods in the second, third, fourth and fifth quintiles, respectively, compared with residents in neighborhoods in the first quintile. The odds ratios for the proportion of parks, squares and gardens were 0.90 (95%CI 0.69;1.19), 1.41 (95%CI 1.04;1.90), 1.63 (95%CI 1.24;2.14) and 1.05 (95%CI 0.80;1.38) for residents in neighborhoods in the second, third, fourth and fifth quintiles. After adjusting for the other variables, only the social development index continued to be associated with leisure-time physical activity, with odds ratios of 1.41 (95%CI 1.02;1.95); 1.54 (95%CI 1.12;2.12); 1.65 (95%CI 1.14;2.39) and 2.13 (95%CI 1.40;3.25) for residents in neighborhoods in the second, third, fourth and fifth quintiles. Leisure-time physical activity was more common in residents in neighborhoods with higher social

Neighborhood contextual characteristics and leisure-time physical activity: Pró-Saúde Study

PubMed Central

Boclin, Karine de Lima Sírio; Faerstein, Eduardo; de Leon, Antônio Carlos Monteiro Ponce

2014-01-01

OBJECTIVE To estimate the association between neighborhood contextual variables and leisure-time physical activity. METHODS Data were analyzed for 2,674 adults from Rio de Janeiro, RJ, Southeastern Brazil, participating in the longitudinal study in 1999. Leisure-time physical activity in the two preceding weeks was assessed dichotomously. Sex, age, income, education and marital status were analyzed as individual variables. Neighborhood contextual characteristics were the social development index, the Theil index and the proportion of the area occupied by parks, squares and gardens, categorized in quintiles. The unadjusted and adjusted odds ratios and 95% confidence intervals were estimated using multilevel logistic regression. RESULTS The prevalence of leisure-time physical activity was higher in residents in neighborhoods with higher indices of social development (between 32.3% and 53.1%) and a greater proportion of parks, squares and gardens (between 35.8% and 53.1%). Regarding the social development index, the adjusted odds ratios for physical activity were 1.22 (95%CI 0.93;1.61), 1.44 (95%CI 1.09;1.89), 1.75 (95%CI 1.31;2.34) and 2.25 (95%CI 1.70;3.00) for residents in neighborhoods in the second, third, fourth and fifth quintiles, respectively, compared with residents in neighborhoods in the first quintile. The odds ratios for the proportion of parks, squares and gardens were 0.90 (95%CI 0.69;1.19), 1.41 (95%CI 1.04;1.90), 1.63 (95%CI 1.24;2.14) and 1.05 (95%CI 0.80;1.38) for residents in neighborhoods in the second, third, fourth and fifth quintiles. After adjusting for the other variables, only the social development index continued to be associated with leisure-time physical activity, with odds ratios of 1.41 (95%CI 1.02;1.95); 1.54 (95%CI 1.12;2.12); 1.65 (95%CI 1.14;2.39) and 2.13 (95%CI 1.40;3.25) for residents in neighborhoods in the second, third, fourth and fifth quintiles. CONCLUSIONS Leisure-time physical activity was more common in residents in

Gallbladder shape extraction from ultrasound images using active contour models.

PubMed

Ciecholewski, Marcin; Chochołowicz, Jakub

2013-12-01

Gallbladder function is routinely assessed using ultrasonographic (USG) examinations. In clinical practice, doctors very often analyse the gallbladder shape when diagnosing selected disorders, e.g. if there are turns or folds of the gallbladder, so extracting its shape from USG images using supporting software can simplify a diagnosis that is often difficult to make. The paper describes two active contour models: the edge-based model and the region-based model making use of a morphological approach, both designed for extracting the gallbladder shape from USG images. The active contour models were applied to USG images without lesions and to those showing specific disease units, namely, anatomical changes like folds and turns of the gallbladder as well as polyps and gallstones. This paper also presents modifications of the edge-based model, such as the method for removing self-crossings and loops or the method of dampening the inflation force which moves nodes if they approach the edge being determined. The user is also able to add a fragment of the approximated edge beyond which neither active contour model will move if this edge is incomplete in the USG image. The modifications of the edge-based model presented here allow more precise results to be obtained when extracting the shape of the gallbladder from USG images than if the morphological model is used. © 2013 Elsevier Ltd. Published by Elsevier Ltd. All rights reserved.

Organized Activity Involvement among Urban Youth: Understanding Family- and Neighborhood- Level Characteristics as Predictors of Involvement.

PubMed

Anderson, Nicole A; Bohnert, Amy M; Governale, Amy

2018-02-22

Research examining factors that predict youth's involvement in organized activities is very limited, despite associations with positive outcomes. Using data from 1043 youth (49% female; 46.4% Hispanic, 35.4% African American, 14.0% Caucasian, and 4.2% other) from the Project on Human Development in Chicago Neighborhoods, this study examined how characteristics of parents (supervision, warmth) and neighborhoods (perceived neighborhood safety and collective efficacy) predict patterns of adolescents' involvement in organized activities concurrently (i.e., intensity) and longitudinally (i.e., type and breadth). Parental supervision predicted adolescents' participation in organized activities across multiple waves. Neighborhood violence was positively associated with concurrent participation in organized activities after controlling for socioeconomic status (SES), whereas higher neighborhood collective efficacy predicted greater breadth in organized activity participation across time. These findings have important implications regarding how to attract and sustain organized activity participation for low-income, urban youth.

Neighborhood green, social support, physical activity, and stress: assessing the cumulative impact.

PubMed

Fan, Yingling; Das, Kirti V; Chen, Qian

2011-11-01

We estimate the cumulative stress mitigating impact of neighborhood greenness by investigating whether neighborhood green mitigates stress directly, and indirectly by encouraging physical activity and/or fostering social support. Using data from a recent community health survey in Chicago and two-stage instrumental variables regression modeling, we find that different components of neighborhood green play distinct roles in influencing stress. Park spaces are found to indirectly mitigate stress by fostering social support. Overall neighborhood vegetation is found to have direct stress mitigation impact, yet the impact is counteracted by its negative effect on social support. When comparing the effect size, park spaces show a more positive impact on health and well-being than the overall neighborhood vegetation level. Policy makers are recommended to focus on creating structured green spaces with public recreation and socialization opportunities rather than simply conserving green spaces in the neighborhood. Previous studies, as they often investigate the direct impact only and rarely use multiple measures of greenness, may have mis-estimated health benefits of neighborhood green. Published by Elsevier Ltd.

The association between objective walkability, neighborhood socio-economic status, and physical activity in Belgian children.

PubMed

D'Haese, Sara; Van Dyck, Delfien; De Bourdeaudhuij, Ilse; Deforche, Benedicte; Cardon, Greet

2014-08-23

Objective walkability is an important correlate of adults' physical activity. Studies investigating the relation between walkability and children's physical activity are scarce. However, in order to develop effective environmental interventions, a profound investigation of this relation is needed in all age groups. The aim of this study was to investigate the association between objective walkability and different domains of children's physical activity, and to investigate the moderating effect of neighborhood socio-economic status in this relation. Data were collected between December 2011 and May 2013 as part of the Belgian Environmental Physical Activity Study in children. Children (9-12 years old; n = 606) were recruited from 18 elementary schools in Ghent (Belgium). Children together with one of their parents completed the Flemish Physical Activity Questionnaire and wore an accelerometer for 7 consecutive days. Children's neighborhood walkability was calculated using geographical information systems. Multilevel cross-classified modeling was used to determine the relationship between children's PA and objectively measured walkability and the moderating effect of neighborhood SES in this relation. In low SES neighborhoods walkability was positively related to walking for transportation during leisure time (β = 0.381 ± 0.124; 95% CI = 0.138, 0.624) and was negatively related to sports during leisure time (β = -0.245 ± 0.121; 95% CI = -0.482, -0.008). In high socio-economic status neighborhoods, walkability was unrelated to children's physical activity. No relations of neighborhood walkability and neighborhood socio-economic status with cycling during leisure time, active commuting to school and objectively measured moderate- to vigorous-intensity physical activity were found. No univocal relation between neighborhood walkability and physical activity was found in 9-12 year old children. Results from international adult studies

A prospective investigation of neighborhood socioeconomic deprivation and physical activity and sedentary behavior in older adults.

PubMed

Xiao, Qian; Keadle, Sarah K; Berrigan, David; Matthews, Charles E

2018-06-01

Neighborhood conditions may have an important impact on physical activity and sedentary behaviors in the older population. Most previous studies in this area are cross-sectional and report mixed findings regarding the effects of neighborhood environment on different types of physical activity. Moreover, little is known about the prospective relationship between neighborhood environment and sedentary behaviors. Our analysis included 136,526 participants from the NIH-AARP Diet and Health Study (age 51-70). Neighborhood socioeconomic deprivation was measured with an index based on census variables and developed using principal component analysis. Physical activity and sedentary behaviors were measured both at baseline (1995-1996) and follow-up (2004-2006). Multiple regression analyses were conducted to examine the prospective relationship between neighborhood deprivation and exercise, non-exercise physical activity, and sedentary behaviors, adjusting for baseline physical activity and sedentary behaviors as well as potential confounders. We found that more severe neighborhood socioeconomic deprivation was prospectively associated with reduced time for exercise (β Q5 vs Q1 (95% confidence interval), hour, -0.85 (-0.95, -0.75)) but increased time spent in non-exercise physical activities (1.16 (0.97, 1.34)), such as household activities, outdoor chores, and walking for transportation. Moreover, people from more deprived neighborhoods were also more likely to engage in prolonged (≥5 h/day) TV viewing (Odds ratio Q5 vs Q1 (95% confidence interval), 1.21 (1.15, 1.27)). In conclusion, neighborhood socioeconomic deprivation is associated with physical activity and sedentary behavior in the older population. These associations may differ for different types of physical activities. Copyright © 2018 Elsevier Inc. All rights reserved.

The relative pose estimation of aircraft based on contour model

NASA Astrophysics Data System (ADS)

Fu, Tai; Sun, Xiangyi

2017-02-01

This paper proposes a relative pose estimation approach based on object contour model. The first step is to obtain a two-dimensional (2D) projection of three-dimensional (3D)-model-based target, which will be divided into 40 forms by clustering and LDA analysis. Then we proceed by extracting the target contour in each image and computing their Pseudo-Zernike Moments (PZM), thus a model library is constructed in an offline mode. Next, we spot a projection contour that resembles the target silhouette most in the present image from the model library with reference of PZM; then similarity transformation parameters are generated as the shape context is applied to match the silhouette sampling location, from which the identification parameters of target can be further derived. Identification parameters are converted to relative pose parameters, in the premise that these values are the initial result calculated via iterative refinement algorithm, as the relative pose parameter is in the neighborhood of actual ones. At last, Distance Image Iterative Least Squares (DI-ILS) is employed to acquire the ultimate relative pose parameters.

Comparing Neighborhood-Focused Activism and Volunteerism: Psychological Well-Being and Social Connectedness

ERIC Educational Resources Information Center

Gilster, Megan E.

2012-01-01

Does participating in neighborhood-focused activism confer different benefits than volunteering? The engagement of community members in neighborhood civic life has been identified as an important component of safe and healthy communities. Research on community engagement has encompassed voluntary associations, volunteering, as well as…

Neighborhood Social Cohesion and Depressive Symptoms Among Latinos: Does Use of Community Resources for Physical Activity Matter?

PubMed

Perez, Lilian G; Arredondo, Elva M; McKenzie, Thomas L; Holguin, Margarita; Elder, John P; Ayala, Guadalupe X

2015-10-01

Greater neighborhood social cohesion is linked to fewer depressive symptoms and greater physical activity, but the role of physical activity on the relationship between neighborhood social cohesion and depression is poorly understood. The purpose of the study was to examine the effects of physical activity on the association between neighborhood social cohesion and depressive symptoms. Multivariate logistic regression tested the moderation of self-reported leisure-time moderate-to-vigorous physical activity (LTMVPA) and active use of parks or recreational facilities on the association between neighborhood social cohesion and depressive symptoms among 295 randomly selected Latino adults who completed a face-to-face interview. After adjusting for age, gender, and income, neighborhood social cohesion and depressive symptoms were inversely related (OR = 0.8; 95% CI: 0.5-1.2). Active use of parks or recreational facilities moderated the association between neighborhood social cohesion and depressive symptoms but meeting the recommendations for LTMVPA did not. Latinos who reported active use of parks or recreational facilities and higher levels of neighborhood social cohesion had fewer depressive symptoms than peers who did not use these spaces. Future studies are needed to test strategies for promoting active use of parks or recreational facilities to address depression in Latinos.

Neighborhood social cohesion and depressive symptoms among Latinos: Does use of community resources for physical activity matter?

PubMed Central

Perez, Lilian G.; Arredondo, Elva M.; McKenzie, Thomas L.; Holguin, Margarita; Elder, John P.; Ayala, Guadalupe X.

2017-01-01

Background Greater neighborhood social cohesion is linked to fewer depressive symptoms and greater physical activity, but the role of physical activity on the relationship between neighborhood social cohesion and depression is poorly understood. The purpose of the study was to examine the effects of physical activity on the association between neighborhood social cohesion and depressive symptoms. Methods Multivariate logistic regression tested the moderation of self-reported leisure time moderate-to vigorous-physical activity (LTMVPA) and active use of parks or recreational facilities on the association between neighborhood social cohesion and depressive symptoms among 295 randomly selected Latino adults who completed a face-to-face interview. Results After adjusting for age, gender, and income, neighborhood social cohesion and depressive symptoms were inversely related (OR=0.8; 95% CI: 0.5–1.2). Active use of parks or recreational facilities moderated the association between neighborhood social cohesion and depressive symptoms but meeting the recommendations for LTMVPA did not. Latinos who reported active use of parks or recreational facilities and higher levels of neighborhood social cohesion had fewer depressive symptoms than peers who did not use these spaces. Conclusions Future studies are needed to test strategies for promoting active use of parks or recreational facilities to address depression in Latinos. PMID:25599244

The association between neighborhood characteristics and body size and physical activity in the California teachers study cohort.

PubMed

Keegan, Theresa H M; Hurley, Susan; Goldberg, Debbie; Nelson, David O; Reynolds, Peggy; Bernstein, Leslie; Horn-Ross, Pam L; Gomez, Scarlett L

2012-04-01

We considered interactions between physical activity and body mass index (BMI) and neighborhood factors. We used recursive partitioning to identify predictors of low recreational physical activity (< 2.5 hours/week) and overweight and obesity (BMI ≥ 25.0 kg/m(2)) among 118,315 women in the California Teachers Study. Neighborhood characteristics were based on 2000 US Census data and Reference US business listings. Low physical activity and being overweight or obese were associated with individual sociodemographic characteristics, including race/ethnicity and age. Among White women aged 36 to 75 years, living in neighborhoods with more household crowding was associated with a higher probability of low physical activity (54% vs 45% to 51%). In less crowded neighborhoods where more people worked outside the home, the existence of fewer neighborhood amenities was associated with a higher probability of low physical activity (51% vs 46%). Among non-African American middle-aged women, living in neighborhoods with a lower socioeconomic status was associated with a higher probability of being overweight or obese (46% to 59% vs 38% in high-socioeconomic status neighborhoods). Associations between physical activity, overweight and obesity, and the built environment varied by sociodemographic characteristics in this educated population.

Generation algorithm of craniofacial structure contour in cephalometric images

NASA Astrophysics Data System (ADS)

Mondal, Tanmoy; Jain, Ashish; Sardana, H. K.

2010-02-01

Anatomical structure tracing on cephalograms is a significant way to obtain cephalometric analysis. Computerized cephalometric analysis involves both manual and automatic approaches. The manual approach is limited in accuracy and repeatability. In this paper we have attempted to develop and test a novel method for automatic localization of craniofacial structure based on the detected edges on the region of interest. According to the grey scale feature at the different region of the cephalometric images, an algorithm for obtaining tissue contour is put forward. Using edge detection with specific threshold an improved bidirectional contour tracing approach is proposed by an interactive selection of the starting edge pixels, the tracking process searches repetitively for an edge pixel at the neighborhood of previously searched edge pixel to segment images, and then craniofacial structures are obtained. The effectiveness of the algorithm is demonstrated by the preliminary experimental results obtained with the proposed method.

Neighborhood Rhythms and the Social Activities of Adolescent Mothers.

ERIC Educational Resources Information Center

Burton, Linda M.; Graham, Joan E.

1998-01-01

A five-year longitudinal ethnographic study explores the relationship between the temporal organization of neighborhood activities and the social engagements of urban African American teen mothers. Found that courting activities occurred during the morning, baby parading during the afternoon-evening, with teen mothers avoiding the illicit drug…

Racial/Ethnic Differences in Associations Between Neighborhood Social Cohesion and Meeting Physical Activity Guidelines, United States, 2013-2014.

PubMed

Yi, Stella S; Trinh-Shevrin, Chau; Yen, Irene H; Kwon, Simona C

2016-12-08

Neighborhood factors are increasingly recognized as determinants of health. Neighborhood social cohesion may be associated with physical activity, but previous studies examined data aggregated across racial/ethnic groups. We assessed whether neighborhood social cohesion was associated with physical activity in a nationally representative data set and explored the role of race/ethnicity. We combined National Health Interview Survey data from 2013 and 2014 (n = 64,754) and constructed a neighborhood social cohesion score by summing responses to 4 questions. The outcome of meeting aerobic physical activity guidelines was defined as 150 or more minutes per week of moderate activity or 75 or more minutes of vigorous activity. Multivariable models regressing physical activity on neighborhood social cohesion were adjusted for demographic factors; interaction analyses assessed effect modification by race/ethnicity. In adjusted analyses, a 1-unit increase in the neighborhood social cohesion score was associated with higher odds of meeting physical activity guidelines (odds ratio [OR], 1.04; 95% confidence interval [CI], 1.03-1.05). Neighborhood social cohesion and physical activity were associated among non-Hispanic white adults (OR, 1.30; 95% CI, 1.20-1.42) and Hispanic adults (OR, 1.18; 95% CI, 1.03-1.34]) but not among non-Hispanic black or Asian American adults (Chinese, Filipino, and Asian Indians). Neighborhood social cohesion was associated with meeting physical activity guidelines in a nationally representative sample; this association may be most meaningful for non-Hispanic white and Hispanic populations. Additional studies are needed to identify neighborhood factors that help non-Hispanic black and Asian Americans to meet physical activity guidelines.

The influence of rural home and neighborhood environments on healthy eating, physical activity, and weight.

PubMed

Kegler, Michelle C; Swan, Deanne W; Alcantara, Iris; Feldman, Lynne; Glanz, Karen

2014-02-01

Despite the recognition that environments play a role in shaping physical activity and healthy eating behaviors, relatively little research has focused on rural homes and neighborhoods as important settings for obesity prevention. This study, conducted through community-based participatory research, used a social ecological model to examine how home and neighborhood food and physical activity environments were associated with weight status among rural-dwelling adults. Data were from a cross-sectional survey of White and African American adults (n = 513) aged 40-70 years living in rural southwest Georgia. Data were analyzed using measured variable path analysis, a form of structural equation modeling. The results support a social ecological approach to obesity prevention. Physical activity had a direct effect on BMI; self-efficacy, family support for physical activity, and household inventory of physical activity equipment also had direct effects on physical activity. Neighborhood walkability had an indirect effect on physical activity through self-efficacy and family social support. Although neither fruit and vegetable intake nor fat intake had direct effects on BMI, self-efficacy and household food inventories had direct effects on dietary behavior. Perceived access to healthy foods in the neighborhood had an indirect effect on healthy eating and a direct effect on weight; neighborhood cohesion had an indirect effect on healthy eating through self-efficacy. Overall, individual factors and home environments tended to exhibit direct effects on behavior, and neighborhood variables more often exhibited an indirect effect.

Aging in Neighborhoods Differing in Walkability and Income: Associations with Physical Activity and Obesity in Older Adults

PubMed Central

King, Abby C.; Sallis, James F.; Frank, Lawrence D.; Saelens, Brian E.; Cain, Kelli; Conway, Terry L.; Chapman, James E.; Ahn, David K.; Kerr, Jacqueline

2011-01-01

While there is a growing literature on the relations between neighborhood design and health factors such as physical activity and obesity, less focus has been placed on older adults, who may be particularly vulnerable to environmental influences. This study evaluates the relations among objectively measured neighborhood design, mobility impairment, and physical activity and body weight in two U.S. regional samples of community dwelling older adults living in neighborhoods differing in walkability and income levels. An observational design involving two time points six months apart was employed between 2005–2008. U.S. Census block groups in Seattle-King County, Washington and Baltimore. Maryland-Washington DC regions were selected via geographic information systems to maximize variability in walkability and income. Participants were 719 adults ages 66 years and older who were able to complete surveys in English and walk at least 10 feet continuously. Measurements included reported walking or bicycling for errands (i.e., transport activity) and other outdoor aerobic activities measured via the CHAMPS questionnaire: accelerometry-based moderate-to-vigorous physical activity; reported body mass index; and reported lower-extremity mobility impairment measured via the Late-Life Function and Disability Instrument. Across regions, time, and neighborhood income, older adults living in more walkable neighborhoods had more transport activity and moderate-to- vigorous physical activity and lower body mass index relative to those living in less walkable neighborhoods. The most mobility-impaired adults living in more walkable neighborhoods reported transport activity levels that were similar to less mobility-impaired adults living in less walkable neighborhoods. The results add to the small literature aimed at understanding how neighborhood design may influence physical activity and related aspects of health linked with day-to-day function and independence as people age. PMID

Aging in neighborhoods differing in walkability and income: associations with physical activity and obesity in older adults.

PubMed

King, Abby C; Sallis, James F; Frank, Lawrence D; Saelens, Brian E; Cain, Kelli; Conway, Terry L; Chapman, James E; Ahn, David K; Kerr, Jacqueline

2011-11-01

While there is a growing literature on the relations between neighborhood design and health factors such as physical activity and obesity, less focus has been placed on older adults, who may be particularly vulnerable to environmental influences. This study evaluates the relations among objectively measured neighborhood design, mobility impairment, and physical activity and body weight in two U.S. regional samples of community dwelling older adults living in neighborhoods differing in walkability and income levels. An observational design involving two time points six months apart was employed between 2005 and 2008. U.S. Census block groups in Seattle-King County, Washington and Baltimore, Maryland-Washington DC regions were selected via geographic information systems to maximize variability in walkability and income. Participants were 719 adults ages 66 years and older who were able to complete surveys in English and walk at least 10 feet continuously. Measurements included reported walking or bicycling for errands (i.e., transport activity) and other outdoor aerobic activities measured via the CHAMPS questionnaire: accelerometry-based moderate-to-vigorous physical activity; reported body mass index; and reported lower extremity mobility impairment measured via the Late-Life Function and Disability Instrument. Across regions, time, and neighborhood income, older adults living in more walkable neighborhoods had more transport activity and moderate-to- vigorous physical activity and lower body mass index relative to those living in less walkable neighborhoods. The most mobility-impaired adults living in more walkable neighborhoods reported transport activity levels that were similar to less mobility-impaired adults living in less walkable neighborhoods. The results add to the small literature aimed at understanding how neighborhood design may influence physical activity and related aspects of health linked with day-to-day function and independence as people age

Neighborhood environment correlates of physical activity and sedentary behavior among Latino adults in Massachusetts.

PubMed

Silfee, Valerie J; Rosal, Milagros C; Sreedhara, Meera; Lora, Vilma; Lemon, Stephenie C

2016-09-13

U.S. Latinos experience high rates of cardio-metabolic diseases and have high rates of physical inactivity and sedentary behavior. Understanding the environmental factors associated with physical activity and sedentary behaviors among Latinos could inform future interventions. The purpose of this study is to explore the neighborhood environment correlates of physical activity and sedentary behavior in a sample of U.S. Latino adults. Cross-sectional study of 602 Latino adults in Lawrence, MA. Survey assessments of physical activity, sedentary behavior, and neighborhood environment were verbally administered. The neighborhood environment scale assessed violence, safety, aesthetic quality, walkability, availability of healthy foods, social cohesion, and activities with neighbors. After controlling forage, gender, education, body mass index (BMI), and smoking status, two variables were associated with the outcomes of interest. Living in more walkable neighborhoods was associated with an increased likelihood of engaging in adequate levels of physical activity (>150 min per week, as recommended by the American College of Sports Medicine (ACSM)) (OR = 1.403, p = .018); and greater frequency of activities with neighbors was associated with greater sedentary behavior (β = .072, p = .05). There were different neighborhood environment correlates of physical activity and sedentary behavior in this Latino community. Focusing on a greater understanding of the distinct social and physical environmental correlates of physical activity and sedentary behavior may provide important insights for reducing CVD risk and health disparities among Latinos.

Contextual Correlates of Physical Activity among Older Adults: A Neighborhood Environment-Wide Association Study (NE-WAS).

PubMed

Mooney, Stephen J; Joshi, Spruha; Cerdá, Magdalena; Kennedy, Gary J; Beard, John R; Rundle, Andrew G

2017-04-01

Background: Few older adults achieve recommended physical activity levels. We conducted a "neighborhood environment-wide association study (NE-WAS)" of neighborhood influences on physical activity among older adults, analogous, in a genetic context, to a genome-wide association study. Methods: Physical Activity Scale for the Elderly (PASE) and sociodemographic data were collected via telephone survey of 3,497 residents of New York City aged 65 to 75 years. Using Geographic Information Systems, we created 337 variables describing each participant's residential neighborhood's built, social, and economic context. We used survey-weighted regression models adjusting for individual-level covariates to test for associations between each neighborhood variable and (i) total PASE score, (ii) gardening activity, (iii) walking, and (iv) housework (as a negative control). We also applied two "Big Data" analytic techniques, LASSO regression, and Random Forests, to algorithmically select neighborhood variables predictive of these four physical activity measures. Results: Of all 337 measures, proportion of residents living in extreme poverty was most strongly associated with total physical activity [-0.85; (95% confidence interval, -1.14 to -0.56) PASE units per 1% increase in proportion of residents living with household incomes less than half the federal poverty line]. Only neighborhood socioeconomic status and disorder measures were associated with total activity and gardening, whereas a broader range of measures was associated with walking. As expected, no neighborhood meaZsures were associated with housework after accounting for multiple comparisons. Conclusions: This systematic approach revealed patterns in the domains of neighborhood measures associated with physical activity. Impact: The NE-WAS approach appears to be a promising exploratory technique. Cancer Epidemiol Biomarkers Prev; 26(4); 495-504. ©2017 AACR See all the articles in this CEBP Focus section, "Geospatial

The Association Between Neighborhood Characteristics and Body Size and Physical Activity in the California Teachers Study Cohort

PubMed Central

Hurley, Susan; Goldberg, Debbie; Nelson, David O.; Reynolds, Peggy; Bernstein, Leslie; Horn-Ross, Pam L.; Gomez, Scarlett L.

2012-01-01

Objectives. We considered interactions between physical activity and body mass index (BMI) and neighborhood factors. Methods. We used recursive partitioning to identify predictors of low recreational physical activity (< 2.5 hours/week) and overweight and obesity (BMI ≥ 25.0 kg/m2) among 118 315 women in the California Teachers Study. Neighborhood characteristics were based on 2000 US Census data and Reference US business listings. Results. Low physical activity and being overweight or obese were associated with individual sociodemographic characteristics, including race/ethnicity and age. Among White women aged 36 to 75 years, living in neighborhoods with more household crowding was associated with a higher probability of low physical activity (54% vs 45% to 51%). In less crowded neighborhoods where more people worked outside the home, the existence of fewer neighborhood amenities was associated with a higher probability of low physical activity (51% vs 46%). Among non–African American middle-aged women, living in neighborhoods with a lower socioeconomic status was associated with a higher probability of being overweight or obese (46% to 59% vs 38% in high–socioeconomic status neighborhoods). Conclusions. Associations between physical activity, overweight and obesity, and the built environment varied by sociodemographic characteristics in this educated population. PMID:21852626

Synchronous activity in cat visual cortex encodes collinear and cocircular contours.

PubMed

Samonds, Jason M; Zhou, Zhiyi; Bernard, Melanie R; Bonds, A B

2006-04-01

We explored how contour information in primary visual cortex might be embedded in the simultaneous activity of multiple cells recorded with a 100-electrode array. Synchronous activity in cat visual cortex was more selective and predictable in discriminating between drifting grating and concentric ring stimuli than changes in firing rate. Synchrony was found even between cells with wholly different orientation preferences when their receptive fields were circularly aligned, and membership in synchronous groups was orientation and curvature dependent. The existence of synchrony between cocircular cells reinforces its role as a general mechanism for contour integration and shape detection as predicted by association field concepts. Our data suggest that cortical synchrony results from common and synchronous input from earlier visual areas and that it could serve to shape extrastriate response selectivity.

Neighborhood environment and physical activity among older adults: do the relationships differ by driving status?

PubMed

Ding, Ding; Sallis, James F; Norman, Gregory J; Frank, Lawrence D; Saelens, Brian E; Kerr, Jacqueline; Conway, Terry L; Cain, Kelli; Hovell, Melbourne F; Hofstetter, C Richard; King, Abby C

2014-07-01

Some attributes of neighborhood environments are associated with physical activity among older adults. This study examined whether the associations were moderated by driving status. Older adults from neighborhoods differing in walkability and income completed written surveys and wore accelerometers (N = 880, mean age = 75 years, 56% women). Neighborhood environments were measured by geographic information systems and validated questionnaires. Driving status was defined on the basis of a driver's license, car ownership, and feeling comfortable to drive. Outcome variables included accelerometer-based physical activity and self-reported transport and leisure walking. Multilevel generalized linear regression was used. There was no significant Neighborhood Attribute × Driving Status interaction with objective physical activity or reported transport walking. For leisure walking, almost all environmental attributes were positive and significant among driving older adults but not among nondriving older adults (five significant interactions at p < .05). The findings suggest that driving status is likely to moderate the association between neighborhood environments and older adults' leisure walking.

Independent Associations and Interactions of Perceived Neighborhood and Psychosocial Constructs on Adults' Physical Activity.

PubMed

Dwyer, Laura A; Patel, Minal; Nebeling, Linda C; Oh, April Y

2018-05-01

Neighborhood and psychosocial variables are related to physical activity (PA), yet interactions between these factors in predicting PA are infrequently studied. This analysis examines the independent associations and interactions between self-reported neighborhood and psychosocial variables in relation to moderate to vigorous PA (MVPA) among adults from a US panel sample. In adjusted models, neighborhood social capital was positively associated with meeting MVPA guidelines. Fewer barriers, greater self-efficacy, and greater autonomous motivation also corresponded with greater odds of meeting MVPA guidelines. An interaction between social capital and autonomous motivation showed that social capital was only associated with MVPA when autonomous motivation was high. Participants who reported both high autonomous motivation and high social capital were most likely to meet MVPA guidelines. Neighborhood social capital, barriers, self-efficacy, and autonomous motivation may be important correlates in promoting adults' PA. Future directions include using objective neighborhood and PA data in similar analyses and investigating associations of neighborhood and psychosocial variables with multiple PA activities. Intervention research to promote PA should also examine whether effects of interventions targeting psychosocial constructs are moderated by features of an individual's neighborhood or whether perceived social capital can be addressed in interventions in conjunction with psychosocial variables.

Do psychosocial factors moderate the association between neighborhood walkability and adolescents' physical activity?

PubMed

De Meester, Femke; Van Dyck, Delfien; De Bourdeaudhuij, Ilse; Deforche, Benedicte; Cardon, Greet

2013-03-01

Ecological models emphasize the interaction between individuals and their environment. Furthermore, they posit that environmental variables influence physical activity (PA) not only directly but also indirectly through their interaction with other factors. This study explored if the association between neighborhood walkability and adolescents' PA is moderated by psychosocial factors using data from the Belgian Environmental PA Study in Youth (BEPAS-Y). BEPAS-Y recruited adolescents from 32 neighborhoods differing in objectively determined neighborhood walkability and income. Between 2008 and 2009, 637 adolescents (13-15 years; 49.4% boys) completed a survey measuring socio-demographic and psychosocial factors and wore an accelerometer for seven days. Multilevel-regression analyses revealed that for adolescents living in low-income neighborhoods, the association between neighborhood walkability and PA is moderated by perceived barriers and perceived benefits toward PA. Neighborhood walkability was positively associated with PA among adolescents, living in low-income neighborhoods, who perceived many barriers and few benefits, while for adolescents who perceived few barriers and many benefits, the PA level was high, irrespective of neighborhood walkability. For adolescents, living in high-income neighborhoods, none of the psychosocial attributes moderated the association between neighborhood walkability and PA. These findings provide some support for the predicted interactions posited by ecological models. Improving neighborhood walkability might increase PA-levels of adolescents living in low-income neighborhoods, with less positive psychosocial profiles, or in other words; those who are most difficult to reach through PA interventions. However, in order to increase PA in large populations, interventions focusing solely on improving neighborhood walkability may not have the desired effect. Copyright © 2013 Elsevier Ltd. All rights reserved.

Automatic exudate detection by fusing multiple active contours and regionwise classification.

PubMed

Harangi, Balazs; Hajdu, Andras

2014-11-01

In this paper, we propose a method for the automatic detection of exudates in digital fundus images. Our approach can be divided into three stages: candidate extraction, precise contour segmentation and the labeling of candidates as true or false exudates. For candidate detection, we borrow a grayscale morphology-based method to identify possible regions containing these bright lesions. Then, to extract the precise boundary of the candidates, we introduce a complex active contour-based method. Namely, to increase the accuracy of segmentation, we extract additional possible contours by taking advantage of the diverse behavior of different pre-processing methods. After selecting an appropriate combination of the extracted contours, a region-wise classifier is applied to remove the false exudate candidates. For this task, we consider several region-based features, and extract an appropriate feature subset to train a Naïve-Bayes classifier optimized further by an adaptive boosting technique. Regarding experimental studies, the method was tested on publicly available databases both to measure the accuracy of the segmentation of exudate regions and to recognize their presence at image-level. In a proper quantitative evaluation on publicly available datasets the proposed approach outperformed several state-of-the-art exudate detector algorithms. Copyright © 2014 Elsevier Ltd. All rights reserved.

Putting Families Into Place: Using Neighborhood-Effects Research and Activity Spaces to Understand Families

PubMed Central

Noah, Aggie J.

2015-01-01

Neighborhood is an important context in which individuals and families are embedded. Yet family studies researchers have been relatively slow to incorporate spatial approaches into family science. Although limited theoretical and methodological attention has been devoted to families in neighborhood-effects research, family scholars can contribute greatly to theories about neighborhood effects, and neighborhood-effects research can help move the field of family studies forward. This article reviews the theories, applications, and limitations of research on neighborhood effects and discusses how family studies can benefit from incorporating a spatial perspective from neighborhood-effects research. I then present an innovative methodology—referred to as activity spaces—emerging in neighborhood-effects research, and I discuss how this approach can be used to better understand the complexity and heterogeneity of families. Last, I highlight ways to incorporate space into family studies by “putting families into place.” PMID:26681979

Parental and Adolescent Perceptions of Neighborhood Safety Related to Adolescents' Physical Activity in Their Neighborhood

ERIC Educational Resources Information Center

Esteban-Cornejo, Irene; Carlson, Jordan A.; Conway, Terry L.; Cain, Kelli L.; Saelens, Brian E.; Frank, Lawrence D.; Glanz, Karen; Roman, Caterina G.; Sallis, James F.

2016-01-01

Purpose: The purpose of this study was to examine the association between adolescent and parental perceptions of neighborhood safety and adolescents' physical activity in multiple locations and to investigate the moderating effect of sex within this association. Method: This cross-sectional study was conducted with 928 adolescents aged 12 to 16…

Associations between observed neighborhood characteristics and physical activity: findings from a multiethnic urban community

PubMed Central

Kwarteng, Jamila L.; Schulz, Amy J.; Mentz, Graciela B.; Zenk, Shannon N.; Opperman, Alisha A.

2014-01-01

Background There is growing interest in the contributions of characteristics of the neighborhood environment to inequalities in physical activity. However, few studies have examined the relationship between observed neighborhood environmental characteristics and physical activity in a multiethnic urban area. Purpose The purpose of this study was to assess relationships between neighborhood environments and physical activity and the extent to which these associations varied by demographic characteristics or perceptions of the physical and social environment. Methods Cross-sectional analyses drew upon data collected from a stratified proportional probability sample of non-Hispanic Black, Hispanic and non-Hispanic White (NHW) adults (n = 919) in low-to-moderate income neighborhoods in Detroit, Michigan. Physical activity was assessed as self-reported duration and frequency of vigorous and moderate physical activity. Observed physical environment was assessed through systematic social observation by trained observers on blocks adjacent to survey respondents' residences. Results We find a positive association of sidewalk condition with physical activity, with stronger effects for younger compared with older residents. In addition, physical disorder was more negatively associated with physical activity among NHW and older residents. Conclusions These findings suggest that sidewalk improvements and reductions in physical disorder in urban communities may promote greater equity in physical activity. PMID:24159053

The social context moderates the relationships between neighborhood safety and adolescents’ physical activities

USDA-ARS?s Scientific Manuscript database

Background. Previous studies of neighborhood safety and physical (in)activity have typically neglected to consider the youth’s peer context as a modifier of these relationships. Objective. Test the independent and interactive effects of perceived neighborhood safety and time spent with friends and p...

Availability of physical activity-related facilities and neighborhood demographic and socioeconomic characteristics: a national study.

PubMed

Powell, Lisa M; Slater, Sandy; Chaloupka, Frank J; Harper, Deborah

2006-09-01

We examined associations between neighborhood demographic characteristics and the availability of commercial physical activity-related outlets by zip code across the United States. Multivariate analyses were conducted to assess the availability of 4 types of outlets: (1) physical fitness facilities, (2) membership sports and recreation clubs, (3) dance facilities, and (4) public golf courses. Commercial outlet data were linked by zip code to US Census Bureau population and socioeconomic data. Results showed that commercial physical activity-related facilities were less likely to be present in lower-income neighborhoods and in neighborhoods with higher proportions of African American residents, residents with His-panic ethnicity, and residents of other racial minority backgrounds. In addition, these neighborhoods had fewer such facilities available. Lack of availability of facilities that enable and promote physical activity may, in part, underpin the lower levels of activity observed among populations of low socioeconomic status and minority backgrounds.

The association between the parental perception of the physical neighborhood environment and children's location-specific physical activity.

PubMed

D'Haese, Sara; Van Dyck, Delfien; De Bourdeaudhuij, Ilse; Deforche, Benedicte; Cardon, Greet

2015-06-19

The relationship between children's physical neighborhood environment and their physical activity, has been largely investigated. However in recent reviews, only a few significant and consistent direct associations between children's physical neighborhood environment and their physical activity were found. This is possibly due to the fact that the location where children's physical activity took place, is insufficiently specified. Therefore, this study aimed to investigate the association between parental perceived neighborhood characteristics and children's physical activity in clearly defined environments. Children (9-12 years; n = 606) wore an Actigraph accelerometer for 7 days. Parents completed the parental version of the Neighborhood Environmental Walkability Scale questionnaire and reported on children's physical activity in specific locations: physical activity in nearby streets and on sidewalks, physical activity in public recreation spaces and physical activity in the garden. Multilevel logistic regression analyses were conducted in MLwiN 2.30. Children were more likely to be active in nearby streets and on sidewalks, if their parents perceived lower street connectivity (OR = 0.479; 95% CI = 0.33 and 0.70), higher land use mix accessibility (OR = 1.704; 95% CI = 1.25 and 2.33) and more crime safety (OR = 1.879; 95% CI = 1.29 and 2.74). Children whose parents perceived higher presence of recreation facilities (OR = 1.618; CI = 1.23; 2.12) were more likely to be active in public recreation spaces. No environmental neighborhood variables were related to physical activity in the garden and overall moderate- to vigorous-intensity physical activity. The parental perceived physical neighborhood environment relates differently to physical activity in different locations. In order to develop effective interventions, it seems promising to further investigate the association between location-specific physical activity and specific

The Social Ecology of Public Space: Active Streets and Violent Crime in Urban Neighborhoods1

PubMed Central

Browning, Christopher R.; Jackson, Aubrey L.

2017-01-01

Drawing on one element of Jacobs' (1961) discussion of the social control benefits of “eyes on the street,” this paper explores the link between the prevalence of active streets and violence in urban neighborhoods. Three distinct data sources from the Project on Human Development in Chicago Neighborhoods are merged to explore the functional form and potential contingency of the active streets-violence relationship: (1) video data capturing the presence of people on neighborhood streets; (2) longitudinal data on adolescents (ages 11 to 16) and their self-reports of witnessing severe violence; and (3) community survey data on neighborhood social organizational characteristics. Results from multilevel models indicate that the proportion of neighborhood streets with adults present exhibits a nonlinear association with exposure to severe violence. At low prevalence, the increasing prevalence of active streets is positively associated with violence exposure. Beyond a threshold, however, increases in the prevalence of active streets serves to reduce the likelihood of violence exposure. The analyses offer no evidence that the curvilinear association between active streets and violence varies by levels of collective efficacy, and only limited evidence that it varies by anonymity. Analyses of data on homicide and violent victimization corroborate these findings. PMID:29606973

Everybody's Doin' It (Right?): Neighborhood Norms and Sexual Activity in Adolescence

PubMed Central

Warner, Tara D.; Giordano, Peggy C.; Manning, Wendy D.; Longmore, Monica A.

2011-01-01

A neighborhood's normative climate is linked to, but conceptually distinct from, its structural characteristics such as poverty and racial/ethnic composition. Given the deleterious consequences of early sexual activity for adolescent health and well-being, it is important to assess normative influences on youth behaviors such as sexual debut, number of sex partners, and involvement in casual sexual experiences. The current study moves beyond prior research by constructing a measure of normative climate that more fully captures neighborhood norms, and analyzing the influence of normative climate on behavior in a longitudinal framework. Using recently geo-coded data from the Toledo Adolescent Relationships Study (TARS), we analyze the effect of normative climate on adolescents' sexual behaviors. Results indicate that variation in neighborhood normative climates increases adolescents' odds of sexual debut and casual sex, and is associated with their number of sex partners, even after accounting for neighborhood structural disadvantage and demographic risk factors. PMID:22427712

Active Contours Driven by Multi-Feature Gaussian Distribution Fitting Energy with Application to Vessel Segmentation.

PubMed

Wang, Lei; Zhang, Huimao; He, Kan; Chang, Yan; Yang, Xiaodong

2015-01-01

Active contour models are of great importance for image segmentation and can extract smooth and closed boundary contours of the desired objects with promising results. However, they cannot work well in the presence of intensity inhomogeneity. Hence, a novel region-based active contour model is proposed by taking image intensities and 'vesselness values' from local phase-based vesselness enhancement into account simultaneously to define a novel multi-feature Gaussian distribution fitting energy in this paper. This energy is then incorporated into a level set formulation with a regularization term for accurate segmentations. Experimental results based on publicly available STructured Analysis of the Retina (STARE) demonstrate our model is more accurate than some existing typical methods and can successfully segment most small vessels with varying width.

A robust and fast active contour model for image segmentation with intensity inhomogeneity

NASA Astrophysics Data System (ADS)

Ding, Keyan; Weng, Guirong

2018-04-01

In this paper, a robust and fast active contour model is proposed for image segmentation in the presence of intensity inhomogeneity. By introducing the local image intensities fitting functions before the evolution of curve, the proposed model can effectively segment images with intensity inhomogeneity. And the computation cost is low because the fitting functions do not need to be updated in each iteration. Experiments have shown that the proposed model has a higher segmentation efficiency compared to some well-known active contour models based on local region fitting energy. In addition, the proposed model is robust to initialization, which allows the initial level set function to be a small constant function.

Racial/Ethnic Differences in Associations Between Neighborhood Social Cohesion and Meeting Physical Activity Guidelines, United States, 2013–2014

PubMed Central

Trinh-Shevrin, Chau; Yen, Irene H.; Kwon, Simona C.

2016-01-01

Introduction Neighborhood factors are increasingly recognized as determinants of health. Neighborhood social cohesion may be associated with physical activity, but previous studies examined data aggregated across racial/ethnic groups. We assessed whether neighborhood social cohesion was associated with physical activity in a nationally representative data set and explored the role of race/ethnicity. Methods We combined National Health Interview Survey data from 2013 and 2014 (n = 64,754) and constructed a neighborhood social cohesion score by summing responses to 4 questions. The outcome of meeting aerobic physical activity guidelines was defined as 150 or more minutes per week of moderate activity or 75 or more minutes of vigorous activity. Multivariable models regressing physical activity on neighborhood social cohesion were adjusted for demographic factors; interaction analyses assessed effect modification by race/ethnicity. Results In adjusted analyses, a 1-unit increase in the neighborhood social cohesion score was associated with higher odds of meeting physical activity guidelines (odds ratio [OR], 1.04; 95% confidence interval [CI], 1.03–1.05). Neighborhood social cohesion and physical activity were associated among non-Hispanic white adults (OR, 1.30; 95% CI, 1.20–1.42) and Hispanic adults (OR, 1.18; 95% CI, 1.03–1.34]) but not among non-Hispanic black or Asian American adults (Chinese, Filipino, and Asian Indians). Conclusion Neighborhood social cohesion was associated with meeting physical activity guidelines in a nationally representative sample; this association may be most meaningful for non-Hispanic white and Hispanic populations. Additional studies are needed to identify neighborhood factors that help non-Hispanic black and Asian Americans to meet physical activity guidelines. PMID:27930284

Neighborhood Social Cohesion as a Mediator of Neighborhood Conditions on Mothers' Engagement in Physical Activity: Results From the Geographic Research on Wellbeing Study.

PubMed

Yuma-Guerrero, Paula J; Cubbin, Catherine; von Sternberg, Kirk

2017-12-01

The purpose of this study was to determine if social cohesion mediates the effects of neighborhood and household-level socioeconomic status (SES), perceptions of neighborhood safety, and access to parks on mothers' engagement in physical activity (PA). Secondary analyses were conducted on cross-sectional data from The Geographic Research on Wellbeing (GROW) study. GROW includes survey data from a diverse sample of 2,750 California mothers. Structural equation modeling was used to test a conceptual multilevel mediation model, proposing social cohesion as a mediator of known predictors of PA. Social cohesion fully mediated the pathway from perceived neighborhood safety to mothers' PA. Social cohesion also mediated the significant relationship between neighborhood SES and PA; however, this mediation finding was not practically significant when considered in the context of the full model. Household SES was significantly positively related to both social cohesion and PA. Park access contributed significantly to social cohesion but not directly to PA Social cohesion did not significantly mediate relationships between park access or household SES and PA. There is a need for public health interventions to improve engagement in PA among individuals and neighborhoods with lower levels of socioeconomic resources. Interventions that create social cohesion within neighborhoods may have positive effects on mothers' PA, particularly in neighborhoods perceived as unsafe.

Neighborhood Social Cohesion as a Mediator of Neighborhood Conditions on Mothers' Engagement in Physical Activity: Results from the Geographic Research on Wellbeing Study

ERIC Educational Resources Information Center

Yuma-Guerrero, Paula J.; Cubbin, Catherine; von Sternberg, Kirk

2017-01-01

Objectives: The purpose of this study was to determine if social cohesion mediates the effects of neighborhood and household-level socioeconomic status (SES), perceptions of neighborhood safety, and access to parks on mothers' engagement in physical activity (PA). Method: Secondary analyses were conducted on cross-sectional data from The…

Neighborhood perceptions moderate the association between the family environment and children's objectively assessed physical activity.

PubMed

D'Haese, Sara; Timperio, Anna; Veitch, Jenny; Cardon, Greet; Van Dyck, Delfien; Salmon, Jo

2013-11-01

This study aimed to investigate whether parents' perceptions of the neighborhood environment moderate associations between the family environment and children's moderate- to vigorous-intensity physical activity (MVPA) outside of school hours. In total, 929 parents of 10-12 year-old children completed a questionnaire concerning the family environment, MVPA levels, and the neighborhood environment. Children wore an Actigraph (AM7164-2.2C) accelerometer. Compared with neighborhood environment factors, the family environment was more frequently associated with children's MVPA. Parental MVPA was positively associated with children's MVPA, but only among children whose parents reported a high presence of sporting venues. Having more restrictive physical activity rules was negatively associated with children's weekday MVPA in neighborhoods with high perceived stranger danger. © 2013 Published by Elsevier Ltd.

Differences in neighborhood social cohesion and aerobic physical activity by Latino subgroup.

PubMed

Murillo, Rosenda; Echeverria, Sandra; Vasquez, Elizabeth

2016-12-01

Previous research has examined the role of neighborhood social cohesion in physical activity outcomes; however, less is known about this relationship across Latino subgroups. The purpose of our study was to examine the association between neighborhood social cohesion and aerobic leisure-time physical activity (LTPA) among Latino adults and to determine whether these associations differ by Latino subgroup. We used cross-sectional 2013-2014 National Health Interview Survey (NHIS) data on Latinos originating from 5 countries/regions (i.e., Latinos of Puerto Rican, Mexican/Mexican-American, Cuban/Cuban-American, Dominican and Central or South American origin) aged ≥18 years (n=11,126). Multivariable logistic regression models were used to estimate associations between self-reported neighborhood social cohesion and meeting aerobic LTPA guidelines. Models were adjusted for age, sex, education, and acculturation. We also investigated whether associations varied by Latino subgroup. In adjusted models for all Latino adults, compared with those reporting low social cohesion, individuals who reported high social cohesion (Odds Ratio [OR]: 1.33; 95% Confidence Interval [CI]: 1.17-1.52) were significantly more likely to meet the aerobic physical activity guideline. When stratified by Latino subgroups, among Mexican/Mexicans-Americans (OR: 1.39; 95% CI: 1.16, 1.66) and Cuban/Cuban Americans (OR: 1.73; 95% CI: 1.00, 2.97) high social cohesion was associated with meeting the aerobic activity guideline. Among Dominicans, those who reported medium social cohesion (OR: 0.52, 95% CI: 0.29, 0.93) were less likely to meet the aerobic activity guideline. When examining aerobic physical activity outcomes in the Latino population, the role of neighborhood social cohesion and the variability among Latino subgroups should be considered.

MRI segmentation by active contours model, 3D reconstruction, and visualization

NASA Astrophysics Data System (ADS)

Lopez-Hernandez, Juan M.; Velasquez-Aguilar, J. Guadalupe

2005-02-01

The advances in 3D data modelling methods are becoming increasingly popular in the areas of biology, chemistry and medical applications. The Nuclear Magnetic Resonance Imaging (NMRI) technique has progressed at a spectacular rate over the past few years, its uses have been spread over many applications throughout the body in both anatomical and functional investigations. In this paper we present the application of Zernike polynomials for 3D mesh model of the head using the contour acquired of cross-sectional slices by active contour model extraction and we propose the visualization with OpenGL 3D Graphics of the 2D-3D (slice-surface) information for the diagnostic aid in medical applications.

Does the social environment moderate associations of the built environment with Latinas' objectively-measured neighborhood outdoor physical activity?

PubMed

Perez, L G; Carlson, J; Slymen, D J; Patrick, K; Kerr, J; Godbole, S; Elder, J P; Ayala, G X; Arredondo, E M

2016-12-01

Favorable perceptions of the built and social neighborhood environment may promote outdoor physical activity (PA). However, little is known about their independent and interactive effects on neighborhood-specific outdoor PA. We examined associations of perceived built and social neighborhood environment factors, and their interactions, with objectively-measured neighborhood outdoor moderate-to-vigorous physical activity (MVPA) among a sample of Latina women in San Diego, CA. Analyses included baseline data collected in 2011-2013 from 86 Latinas with ≥ 2 days of combined accelerometer and global positioning system data and complete survey measures. We examined objective neighborhood outdoor MVPA within 500-meter home buffers. Generalized linear mixed models examined associations of 3 perceived built (e.g., sidewalk maintenance) and 3 social environmental (e.g., safety from crime) factors with engaging in any daily neighborhood outdoor MVPA. Models tested interactions between the built and social environmental factors. Although the perceived neighborhood environmental factors were not significantly related to daily neighborhood outdoor MVPA, we found 2 significant interactions: perceived sidewalk maintenance x safety from crime ( p  = 0.05) and neighborhood aesthetics x neighborhood social cohesion ( p  = 0.03). Sidewalk maintenance was positively related to daily neighborhood outdoor MVPA only among Latinas that reported low levels of safety from crime. Neighborhood aesthetics was positively related to daily neighborhood outdoor MVPA only among Latinas with high neighborhood social cohesion. Findings suggest several built and social environmental factors interact to influence Latinas' neighborhood outdoor MVPA. Interventions are needed targeting both built and social neighborhood environmental factors favorable to outdoor PA in the neighborhood.

Neighborhood Environment Walkability Scale for Youth (NEWS-Y): reliability and relationship with physical activity.

PubMed

Rosenberg, Dori; Ding, Ding; Sallis, James F; Kerr, Jacqueline; Norman, Gregory J; Durant, Nefertiti; Harris, Sion K; Saelens, Brian E

2009-01-01

To examine the psychometric properties of the Neighborhood Environment Walkability Scale-Youth (NEWS-Y) and explore its associations with context-specific and overall physical activity (PA) among youth. In 2005, parents of children ages 5-11 (n=116), parents of adolescents ages 12-18 (n=171), and adolescents ages 12-18 (n=171) from Boston, Cincinnati, and San Diego, completed NEWS-Y surveys regarding perceived land use mix-diversity, recreation facility availability, pedestrian/automobile traffic safety, crime safety, aesthetics, walking/cycling facilities, street connectivity, land use mix-access, and residential density. A standardized neighborhood environment score was derived. Self-reported activity in the street and in parks, and walking to parks, shops, school, and overall physical activity were assessed. The NEWS-Y subscales had acceptable test-retest reliability (ICC range .56-.87). Being active in a park, walking to a park, walking to shops, and walking to school were related to multiple environmental attributes in all three participant groups. Total neighborhood environment, recreation facilities, walking and cycling facilities, and land use mix-access had the most consistent relationships with specific types of activity. The NEWS-Y has acceptable reliability and subscales were significantly correlated with specific types of youth PA. The NEWS-Y can be used to examine neighborhood environment correlates of youth PA.

Kids in space: Measuring children's residential neighborhoods and other destinations using activity space GPS and wearable camera data.

PubMed

Chambers, T; Pearson, A L; Kawachi, I; Rzotkiewicz, Z; Stanley, J; Smith, M; Barr, M; Ni Mhurchu, C; Signal, L

2017-11-01

Defining the boundary of children's 'neighborhoods' has important implications for understanding the contextual influences on child health. Additionally, insight into activities that occur outside people's neighborhoods may indicate exposures that place-based studies cannot detect. This study aimed to 1) extend current neighborhood research, using data from wearable cameras and GPS devices that were worn over several days in an urban setting; 2) define the boundary of children's neighborhoods by using leisure time activity space data; and 3) determine the destinations visited by children in their leisure time, outside their neighborhoods. One hundred and fourteen children (mean age 12y) from Wellington, New Zealand wore wearable cameras and GPS recorders. Residential Euclidean buffers at incremental distances were paired with GPS data (thereby identifying time spent in different places) to explore alternative definitions of neighborhood boundaries. Children's neighborhood boundary was at 500 m. A newly developed software application was used to identify 'destinations' visited outside the neighborhood by specifying space-time parameters. Image data from wearable cameras were used to determine the type of destination. Children spent over half of their leisure time within 500 m of their homes. Children left their neighborhood predominantly to visit school (for leisure purposes), other residential locations (e.g. to visit friends) and food retail outlets (e.g. convenience stores, fast food outlets). Children spent more time at food retail outlets than at structured sport and in outdoor recreation locations combined. Person-centered neighborhood definitions may serve to better represent children's everyday experiences and neighborhood exposures than previous methods based on place-based measures. As schools and other residential locations (friends and family) are important destinations outside the neighborhood, such destinations should be taken into account. The

Breast boundary detection with active contours

NASA Astrophysics Data System (ADS)

Balic, I.; Goyal, P.; Roy, O.; Duric, N.

2014-03-01

Ultrasound tomography is a modality that can be used to image various characteristics of the breast, such as sound speed, attenuation, and reflectivity. In the considered setup, the breast is immersed in water and scanned along the coronal axis from the chest wall to the nipple region. To improve image visualization, it is desirable to remove the water background. To this end, the 3D boundary of the breast must be accurately estimated. We present an iterative algorithm based on active contours that automatically detects the boundary of a breast using a 3D stack of attenuation images obtained from an ultrasound tomography scanner. We build upon an existing method to design an algorithm that is fast, fully automated, and reliable. We demonstrate the effectiveness of the proposed technique using clinical data sets.

Sulci segmentation using geometric active contours

NASA Astrophysics Data System (ADS)

Torkaman, Mahsa; Zhu, Liangjia; Karasev, Peter; Tannenbaum, Allen

2017-02-01

Sulci are groove-like regions lying in the depth of the cerebral cortex between gyri, which together, form a folded appearance in human and mammalian brains. Sulci play an important role in the structural analysis of the brain, morphometry (i.e., the measurement of brain structures), anatomical labeling and landmark-based registration.1 Moreover, sulcal morphological changes are related to cortical thickness, whose measurement may provide useful information for studying variety of psychiatric disorders. Manually extracting sulci requires complying with complex protocols, which make the procedure both tedious and error prone.2 In this paper, we describe an automatic procedure, employing geometric active contours, which extract the sulci. Sulcal boundaries are obtained by minimizing a certain energy functional whose minimum is attained at the boundary of the given sulci.

Relationship between neighborhood walkability and older adults' physical activity: results from the Belgian Environmental Physical Activity Study in Seniors (BEPAS Seniors).

PubMed

Van Holle, Veerle; Van Cauwenberg, Jelle; Van Dyck, Delfien; Deforche, Benedicte; Van de Weghe, Nico; De Bourdeaudhuij, Ilse

2014-08-23

Adequate knowledge on environmental correlates of physical activity (PA) in older adults is needed to develop effective health promotion initiatives. However, research in this age group is scarce and most existing studies were conducted in North America. The present study aimed to examine relationships between GIS-based neighborhood walkability and objective and self-reported PA in community-dwelling Belgian older adults. Furthermore, moderating effects of neighborhood income levels were investigated. The Belgian Environmental Physical Activity Study (BEPAS) for Seniors is a cross-sectional study in older adults (≥65 yrs) and was conducted between October 2010 and September 2012. Data from 438 older adults living in 20 neighborhoods across Ghent (Belgium) were analyzed. Stratification of selected neighborhoods was based upon objective walkability and neighborhood income. Participants wore an accelerometer during seven consecutive days to obtain objective levels of moderate-to-vigorous physical activity (MVPA). Self-reported levels of transportation walking/cycling and recreational walking/cycling were assessed using the International Physical Activity Questionnaire (long, last 7 days version) adapted for the elderly. Multi-level regression analyses were conducted. Findings showed a positive relationship between neighborhood walkability and weekly minutes of older adults' self-reported walking for transportation (B = 4.63 ± 1.05;p < 0.001) and a negative relationship between walkability and accelerometer-derived low-light PA (B = -1.38 ± 0.62;p = 0.025). Walkability was not related to any measure of recreational PA. A walkability x income interaction was found for accelerometer-derived MVPA (B = -1.826 ± 1.03;p = 0.075), showing only a positive association between walkability and MVPA in low-income neighborhood residents. This was the first European study to examine walkability-PA relationships in older adults. These Belgian findings suggest that a high

Neighborhood Environment, Self-Efficacy, and Physical Activity in Urban Adolescents

ERIC Educational Resources Information Center

Voorhees, Carolyn C.; Yan, Alice F.; Clifton, Kelly J.; Wang, Min Qi

2011-01-01

Objectives: To test the pathways between perceptions of built environment factors and physical activity in urban youth. Methods: Three hundred fifty high school students' perceptions of neighborhood, and barrier self efficacy were measured by a Web survey. Physical activities were assessed using a one-week diary and accelerometers. Results:…

Relations of Neighborhood Environment Influences, Physical Activity, and Active Transportation to/from School across African American, Latino American, and White Girls in the United States.

PubMed

Duncan, Susan C; Strycker, Lisa A; Chaumeton, Nigel R; Cromley, Ellen K

2016-04-01

Neighborhood environment influences may be particularly important for understanding physical activity (PA) patterns across ethnic subgroups of early adolescent girls. This study examined relationships between neighborhood variables, moderate to vigorous physical activity (MVPA), and active transportation to/from school across African American, Latino American, and White early adolescent girls living in an urban/suburban community in the northwestern U.S.A. Relations between the neighborhood variables across ethnic groups also were examined. The sample comprised 372 African American, Latino American, and White girls living in the U.S.A. (mean age = 12.06 years; SD = 1.69). Data were analyzed using multiple-sample structural equation modeling. Results showed that girls' MVPA was positively related to physical activity facility accessibility and negatively related to age. Active transport was positively related to physical activity facility accessibility, neighborhood walkability, and age, and negatively related to distance to the nearest school and household income. Findings highlight the importance of both perceived and objective neighborhood influences on girls' MVPA and active transport. Consistencies in findings across African American, Latino American, and White girls suggest that neighborhood-level PA promotion has the potential for broad impact across all three ethnic groups.

Perceived neighborhood environmental characteristics and different types of physical activity among Brazilian adolescents.

PubMed

Mendonça, Gerfeson; Florindo, Alex Antonio; Rech, Cassiano Ricardo; Freitas, Delma Katiana Silva de; Farias Júnior, José Cazuza de

2018-05-01

Little is known about the association between environmental characteristics and types of physical activity in adolescents in a Latin American context. The aim of this study was to examine the association between perceived neighborhood environmental characteristics and different types of physical activity in 2,874 adolescents from Joao Pessoa, Paraiba State, Northeastern Brazil. The types of activity measured by questionnaire (≥10 min/day) included sports, physical exercises, active commuting and recreational activities. Neighborhood characteristics were measured by a 15-item scale. Multilevel analyses showed that adolescents who reported "having places they liked to go to" (OR = 1.41; 95%CI: 1.10-1.79) and "places with opportunities to practice" (OR = 1.29; 95%CI: 1.01-1.65) were more likely to play sports. "Seeing interesting things while walking" (OR = 1.24; 95%CI: 1.01-1.53) and "Seeing other adolescents engaged in physical activity" (OR = 1.47; 95%CI: 1,05-2,06) were associated with exercises. "Seeing other adolescents engaged in physical activity" (OR = 1.47; 95%CI: 1.18-1.82), "the neighborhood is not violent" (OR = 1.29; 95%CI: 1.04-1.60) and "having places they like to go to" (OR = 1.59; 95%CI: 1.13-2.25) were positively associated and "places with opportunities to practice" (OR = 0.79; 95%CI: 0.63-0.98) inversely related to active commuting. "Seeing other adolescents engaged in physical activities" (OR = 1.31; 95%CI: 1.05-1.63) and "seeing interesting things while walking" (OR = 1.26; 95%CI: 1.02-1.56) were associated with recreational activities. Neighborhood environmental characteristics associated with the physical activity vary with the type of practices adopted by adolescents.

Neighborhood and family perceived environments associated with children's physical activity and body mass index.

PubMed

Lavin Fueyo, Julieta; Totaro Garcia, Leandro Martin; Mamondi, Veronica; Pereira Alencar, Gizelton; Florindo, Alex Antonio; Berra, Silvina

2016-01-01

A growing body of research has been examining neighborhood environment related to children's physical activity and obesity. However, there is still not enough evidence from Latin America. To investigate the association of neighborhood and family perceived environments, use of and distance to public open spaces with leisure-time physical activity (LTPA) and body mass index (BMI) in Argentinean school-aged children. School-based, cross-sectional study with 1777 children (9 to 11years) and their parents, in Cordoba city during 2011. Children were asked about LTPA and family perceived environment. Parents were asked about neighborhood perceived environment, children's use of public open spaces and distance. Weight and height were measured for BMI. We modeled children's LTPA and BMI z-score with structural equation models with latent variables for built, social and safety neighborhood environments. Parents' perceived neighborhood environment was not related with children's LTPA and BMI. Children's perceived autonomy and family environment were positively associated with LTPA. Use of unstructured open spaces and, indirectly, the distance to these, was associated with LTPA among girls. Greater distance to parks reduced their use by children. Policies to increase children's LTPA should include access to better public open spaces, increasing options for activity. A family approach should be incorporated, reinforcing its role for healthy development. Copyright © 2015 Elsevier Inc. All rights reserved.

Neighborhood Predictors of Cognitive Training Outcomes and Trajectories in ACTIVE

PubMed Central

Meyer, Oanh L.; Sisco, Shannon M.; Harvey, Danielle; Zahodne, Laura B.; Glymour, M. Maria; Manly, Jennifer J.; Marsiske, Michael

2015-01-01

We examined the influence of neighborhood socioeconomic position (SEP), racial/ethnic composition, and living in a major city on cognitive trajectories and intervention outcomes. Data came from the Advanced Cognitive Training for Independent and Vital Elderly (ACTIVE) study (N = 2,438). Mixed effects analyses examined associations between neighborhood variables and memory, reasoning, speed of processing, and everyday cognition, estimating differences in initial gains (potentially related to practice) and long-term rate of change over 10 years. The effect of reasoning training on initial gain was weaker for individuals in a major city. For everyday cognition, there was a stronger initial gain for memory-trained and control participants in areas with more racial/ethnic minorities, and for speed-trained and control individuals in higher SEP areas. The racial/ethnic minority effect was no longer significant after adjustment for multiple comparisons. Neighborhood factors may be more important in practice-related improvement than in long-term change. PMID:26667987

Neighborhood design for walking and biking: physical activity and body mass index.

PubMed

Brown, Barbara B; Smith, Ken R; Hanson, Heidi; Fan, Jessie X; Kowaleski-Jones, Lori; Zick, Cathleen D

2013-03-01

Neighborhood designs often relate to physical activity and to BMI. Does neighborhood walkability/bikeability relate to BMI and obesity risk and does moderate-to-vigorous physical activity (MVPA) account for some of the relationship? Census 2000 provided walkability/bikeability measures-block group proportions of workers who walk or bike to work, housing age, and population density-and National Health and Nutrition Examination Study (NHANES 2003-2006) provided MVPA accelerometer measures. Regression analyses (2011-2012) adjusted for geographic clustering and multiple control variables. Greater density and older housing were associated with lower male BMI in bivariate analyses, but there were no density and housing age effects in multivariate models. For women, greater proportions of neighborhood workers who walk to work (M=0.02) and more MVPA was associated with lower BMI and lower obesity risk. For men, greater proportions of workers who bike to work (M=0.004) and more MVPA was associated with lower BMI and obesity risk. For both effects, MVPA partially mediated the relationships between walkability/bikeability and BMI. If such associations are causal, doubling walk and bike-to-work proportions (to 0.04 and 0.008) would have -0.3 and -0.33 effects on the average BMIs of adult women and men living in the neighborhood. This equates to 1.5 pounds for a 64-inch-tall woman and 2.3 pounds for a 69-inch-tall man. Although walking/biking to work is rare in the U.S., greater proportions of such workers in neighborhoods relate to lower weight and higher MVPA. Bikeability merits greater attention as a modifiable activity-friendliness factor, particularly for men. Copyright © 2013 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

Segmentation Using Multispectral Adaptive Contours

DTIC Science & Technology

2004-02-29

Geometry, University of Toronto Press, 1959. 13. R . Malladi , J. Sethian, “Image Processing via Level Set Curvature Flow,” National Academy of Science, vol...92, pp. 7046, 1995. 14. R . Malladi , J. Sethian, C. Vemuri, "Shape Modeling with Front Propagation: a Level Set Approach," IEEE Transactions on...boundary-based active contour models are reviewed in this report; geometric active contours proposed by Caselles et al. [2] and by Malladi and Sethian [13

Walking mediates associations between neighborhood activity supportiveness and BMI in the Women's Health Initiative San Diego cohort.

PubMed

Carlson, Jordan A; Remigio-Baker, Rosemay A; Anderson, Cheryl A M; Adams, Marc A; Norman, Gregory J; Kerr, Jacqueline; Criqui, Michael H; Allison, Matthew

2016-03-01

To investigate whether walking mediates neighborhood built environment associations with weight status in middle- and older-aged women. Participants (N=5085; mean age=64 ± 7.7; 75.4% White non-Hispanic) were from the Women's Health Initiative San Diego cohort baseline visits. Body mass index (BMI) and waist circumference were measured objectively. Walking was assessed via survey. The geographic information system (GIS)-based home neighborhood activity supportiveness index included residential density, street connectivity, land use mix, and number of parks. BMI was 0.22 units higher and the odds ratio for being obese (vs. normal or overweight) was 8% higher for every standard deviation decrease in neighborhood activity supportiveness. Walking partially mediated these associations (22-23% attenuation). Findings were less robust for waist circumference. Findings suggest women who lived in activity-supportive neighborhoods had a lower BMI than their counterparts, in part because they walked more. Improving neighborhood activity supportiveness has population-level implications for improving weight status and health. Copyright © 2016 Elsevier Ltd. All rights reserved.

Stepping towards causation: do built environments or neighborhood and travel preferences explain physical activity, driving, and obesity?

PubMed

Frank, Lawrence Douglas; Saelens, Brian E; Powell, Ken E; Chapman, James E

2007-11-01

Evidence documents associations between neighborhood design and active and sedentary forms of travel. Most studies compare travel patterns for people located in different types of neighborhoods at one point in time adjusting for demographics. Most fail to account for either underlying neighborhood selection factors (reasons for choosing a neighborhood) or preferences (neighborhoods that are preferred) that impact neighborhood selection and behavior. Known as self-selection, this issue makes it difficult to evaluate causation among built form, behavior, and associated outcomes and to know how much more walking and less driving could occur through creating environments conducive to active transport. The current study controls for neighborhood selection and preference and isolates the effect of the built environment on walking, car use, and obesity. Separate analyses were conducted among 2056 persons in the Atlanta, USA based Strategies for Metropolitan Atlanta's Regional Transportation and Air Quality (SMARTRAQ) travel survey on selection factors and 1466 persons in the SMARTRAQ community preference sub-survey. A significant proportion of the population are "mismatched" and do not live in their preferred neighborhood type. Factors influencing neighborhood selection and individual preferences, and current neighborhood walkability explained vehicle travel distance after controlling for demographic variables. Individuals who preferred and lived in a walkable neighborhood walked most (33.9% walked) and drove 25.8 miles per day on average. Individuals that preferred and lived in car dependent neighborhoods drove the most (43 miles per day) and walked the least (3.3%). Individuals that do not prefer a walkable environment walked little and show no change in obesity prevalence regardless of where they live. About half as many participants were obese (11.7%) who prefer and live in walkable environments than participants who prefer car dependent environments (21.6%). Findings

Adolescents' physical activity: competition between perceived neighborhood sport facilities and home media resources.

PubMed

Wong, Bonny Yee-Man; Cerin, Ester; Ho, Sai-Yin; Mak, Kwok-Kei; Lo, Wing-Sze; Lam, Tai-Hing

2010-04-01

To examine the independent, competing, and interactive effects of perceived availability of specific types of media in the home and neighborhood sport facilities on adolescents' leisure-time physical activity (PA). Survey data from 34 369 students in 42 Hong Kong secondary schools were collected (2006-07). Respondents reported moderate-to-vigorous leisure-time PA, presence of sport facilities in the neighborhood and of media equipment in the home. Being sufficiently physically active was defined as engaging in at least 30 minutes of non-school leisure-time PA on a daily basis. Logistic regression and post-estimation linear combinations of regression coefficients were used to examine the independent and competing effects of sport facilities and media equipment on leisure-time PA. Perceived availability of sport facilities was positively (OR(boys) = 1.17; OR(girls) = 1.26), and that of computer/Internet negatively (OR(boys) = 0.48; OR(girls) = 0.41), associated with being sufficiently active. A significant positive association between video game console and being sufficiently active was found in girls (OR(girls) = 1.19) but not in boys. Compared with adolescents without sport facilities and media equipment, those who reported sport facilities only were more likely to be physically active (OR(boys) = 1.26; OR(girls) = 1.34), while those who additionally reported computer/Internet were less likely to be physically active (OR(boys) = 0.60; OR(girls) = 0.54). Perceived availability of sport facilities in the neighborhood may positively impact on adolescents' level of physical activity. However, having computer/Internet may cancel out the effects of active opportunities in the neighborhood. This suggests that physical activity programs for adolescents need to consider limiting the access to computer-mediated communication as an important intervention component.

Joint Associations of Residential Density and Neighborhood Involvement with Physical Activity among a Multiethnic Sample of Urban Adults

ERIC Educational Resources Information Center

Johnson-Lawrence, Vicki; Schulz, Amy J.; Zenk, Shannon N.; Israel, Barbara A.; Wineman, Jean; Marans, Robert W.; Rowe, Zachary

2015-01-01

Regular physical activity is associated with improvements in overall health. Although resident involvement in neighborhood social activities is positively associated with physical activity, neighborhood design features, including residential density, have varied associations with physical activity. Using data from a multiethnic sample of 696…

The built environment, neighborhood safety, and physical activity among low-income children.

DOT National Transportation Integrated Search

2009-09-01

There is a growing body of evidence that environmental factors are related to physical activity and active modes of transportation. There is a separate body of research that links neighborhood safety to physical activity. This study used a cross sect...

Mexican-American children's perspectives: neighborhood characteristics and physical activity in Texas-Mexico border colonias.

PubMed

Mier, Nelda; Lee, Chanam; Smith, Matthew Lee; Wang, Xiaohui; Irizarry, David; Avila-Rodriguez, Elias H; Trevino, Laura; Ory, Marcia G

2013-10-01

The qualitative study described in this article investigated perceptions about environmental factors influencing physical activity (PA) among children from underserved neighborhoods known as colonias in the U.S.-Mexico border. Ten focus groups were conducted with 67 Mexican-American colonia children ages 8 to 13 living in one of the poorest border counties in the U.S. Analyses indicated that PA among children was influenced by neighborhood characteristics, including litter, speeding cars, unleashed dogs, and dark streets. The children also underlined intrapersonal and social environmental factors. Findings may inform policy makers and public health professionals about ways to promote PA among underserved children through urban planning and programs focusing on PA-supportive infrastructure, neighborhood safety, and family- and home-based physical activities.

How neighborhood structural and institutional features can shape neighborhood social connectedness: a multilevel study of adolescent perceptions.

PubMed

Lenzi, Michela; Vieno, Alessio; Santinello, Massimo; Perkins, Douglas D

2013-06-01

According to the norms and collective efficacy model, the levels of social connectedness within a local community are a function of neighborhood structural characteristics, such as socioeconomic status and ethnic composition. The current work aims to determine whether neighborhood structural and institutional features (neighborhood wealth, percentage of immigrants, population density, opportunities for activities and meeting places) have an impact on different components of neighborhood social connectedness (intergenerational closure, trust and reciprocity, neighborhood-based friendship and personal relationships with neighbors). The study involved a representative sample of 389 early and middle adolescents aged 11-15 years old, coming from 31 Italian neighborhoods. Using hierarchical linear modeling, our findings showed that high population density, ethnic diversity, and physical and social disorder might represent obstacles for the creation of social ties within the neighborhood. On the contrary, the presence of opportunities for activities and meeting places in the neighborhood was associated with higher levels of social connectedness among residents.

Phonotactics, Neighborhood Activation, and Lexical Access for Spoken Words

PubMed Central

Vitevitch, Michael S.; Luce, Paul A.; Pisoni, David B.; Auer, Edward T.

2012-01-01

Probabilistic phonotactics refers to the relative frequencies of segments and sequences of segments in spoken words. Neighborhood density refers to the number of words that are phonologically similar to a given word. Despite a positive correlation between phonotactic probability and neighborhood density, nonsense words with high probability segments and sequences are responded to more quickly than nonsense words with low probability segments and sequences, whereas real words occurring in dense similarity neighborhoods are responded to more slowly than real words occurring in sparse similarity neighborhoods. This contradiction may be resolved by hypothesizing that effects of probabilistic phonotactics have a sublexical focus and that effects of similarity neighborhood density have a lexical focus. The implications of this hypothesis for models of spoken word recognition are discussed. PMID:10433774

Perceptions of neighborhood park quality: associations with physical activity and body mass index.

PubMed

Bai, Hua; Wilhelm Stanis, Sonja A; Kaczynski, Andrew T; Besenyi, Gina M

2013-02-01

Parks are important resources for physical activity (PA), yet few studies have examined how perceptions of park characteristics relate to PA and health. This study investigated associations between perceptions of neighborhood park quality and overall moderate-to-vigorous PA (MVPA), park-based PA, and body mass index (BMI). Data were collected via questionnaire from 893 households in Kansas City, Missouri. The newly developed neighborhood park quality scale demonstrated good test-retest and internal reliability. Residents' perceptions of neighborhood park quality were related to PA and health outcomes. Perceiving parks as a benefit was positively related to overall MVPA and park-based PA and negatively related to BMI. Perceptions of well-used parks were positively related to BMI, while perceived cleanliness was negatively related to park-based PA. Better measuring and understanding how perceptions of local parks are associated with PA and health can improve appreciation of how parks facilitate active living.

The influence of travel attitudes, commute mode choice, and perceived neighborhood characteristics on physical activity.

PubMed

Morckel, Victoria; Terzano, Kathryn

2014-01-01

This study examines the relationships between physical activity, travel attitudes, commute mode choice, and perceived neighborhood characteristics. A recent study found that people who walk or bike during their commute exercise more outside of the commute than do people who commute by mass transit or car. The current study seeks to explain what might account for this relationship, using ANOVA models (Method) conducted on survey data from 3 cities. Perceived neighborhood characteristics and travel attitudes influence participants' reported physical activity levels both during the commute and outside of the commute. While the study does not establish causality, the results provide some support for the notion that policy makers interested in increasing physical activity levels should consider changing not only the physical environment, but also perceived neighborhood characteristics and travel attitudes.

Rural Neighborhood Walkability: Implications for Assessment.

PubMed

Kegler, Michelle C; Alcantara, Iris; Haardörfer, Regine; Gemma, Alexandra; Ballard, Denise; Gazmararian, Julie

2015-06-16

Physical activity levels, including walking, are lower in the southern U.S., particularly in rural areas. This study investigated the concept of rural neighborhood walkability to aid in developing tools for assessing walkability and to identify intervention targets in rural communities. Semi-structured interviews were conducted with physically active adults (n = 29) in rural Georgia. Mean age of participants was 55.9 years; 66% were male, 76% were white, and 24% were African American. Participants drew maps of their neighborhoods and discussed the relevance of typical domains of walkability to their decisions to exercise. Comparative analyses were conducted to identify major themes. The majority felt the concept of neighborhood was applicable and viewed their neighborhood as small geographically (less than 0.5 square miles). Sidewalks were not viewed as essential for neighborhood-based physical activity and typical destinations for walking were largely absent. Destinations within walking distance included neighbors' homes and bodies of water. Views were mixed on whether shade, safety, dogs, and aesthetics affected decisions to exercise in their neighborhoods. Measures of neighborhood walkability in rural areas should acknowledge the small size of self-defined neighborhoods, that walking in rural areas is likely for leisure time exercise, and that some domains may not be relevant.

Using Citizen Scientists to Gather, Analyze, and Disseminate Information About Neighborhood Features That Affect Active Living.

PubMed

Winter, Sandra J; Goldman Rosas, Lisa; Padilla Romero, Priscilla; Sheats, Jylana L; Buman, Matthew P; Baker, Cathleen; King, Abby C

2016-10-01

Many Latinos are insufficiently active, partly due to neighborhoods with little environmental support for physical activity. Multi-level approaches are needed to create health-promoting neighborhoods in disadvantaged communities. Participant "citizen scientists" were adolescent (n = 10, mean age = 12.8 ± 0.6 years) and older adult (n = 10, mean age = 71.3 ± 6.5 years), low income Latinos in North Fair Oaks, California. Citizen scientists conducted environmental assessments to document perceived barriers to active living using the Stanford Healthy Neighborhood Discovery Tool, which records GPS-tracked walking routes, photographs, audio narratives, and survey responses. Using a community-engaged approach, citizen scientists subsequently attended a community meeting to engage in advocacy training, review assessment data, prioritize issues to address and brainstorm potential solutions and partners. Citizen scientists each conducted a neighborhood environmental assessment and recorded 366 photographs and audio narratives. Adolescents (n = 4), older adults (n = 7) and community members (n = 4) collectively identified reducing trash and improving personal safety and sidewalk quality as the priority issues to address. Three adolescent and four older adult citizen scientists volunteered to present study findings to key stakeholders. This study demonstrated that with minimal training, low-income, Latino adolescent and older adult citizen scientists can: (1) use innovative technology to gather information about features of their neighborhood environment that influence active living, (2) analyze their information and identify potential solutions, and (3) engage with stakeholders to advocate for the development of healthier neighborhoods.

Using Citizen Scientists to Gather, Analyze, and Disseminate Information about Neighborhood Features that Affect Active Living

PubMed Central

Winter, Sandra J; Rosas, Lisa Goldman; Romero, Priscilla Padilla; Sheats, Jylana L; Buman, Matthew P; Baker, Cathleen; King, Abby C

2015-01-01

Background Many Latinos are insufficiently active, partly due to neighborhoods with little environmental support for physical activity. Multi-level approaches are needed to create health-promoting neighborhoods in disadvantaged communities. Methods Participant “citizen scientists” were adolescent (n=10, mean age=12.8±0.6 years) and older adult (n=10, mean age=71.3±6.5 years), low income Latinos in North Fair Oaks, California. Citizen scientists conducted environmental assessments to document perceived barriers to active living using the Stanford Healthy Neighborhood Discovery Tool, which records GPS-tracked walking routes, photographs, audio narratives, and survey responses. Using a community-engaged approach, citizen scientists subsequently attended a community meeting to engage in advocacy training, review assessment data, prioritize issues to address and brainstorm potential solutions and partners. Results Citizen scientists each conducted a neighborhood environmental assessment and recorded 366 photographs and audio narratives. Adolescents (n=4), older adults (n=7) and community members (n=4) collectively identified reducing trash and improving personal safety and sidewalk quality as the priority issues to address. Three adolescent and four older adult citizen scientists volunteered to present study findings to key stakeholders. Conclusions This study demonstrated that with minimal training, low-income, Latino adolescent and older adult citizen scientists can: 1) use innovative technology to gather information about features of their neighborhood environment that influence active living, 2) analyze their information and identify potential solutions, and 3) engage with stakeholders to advocate for the development of healthier neighborhoods. PMID:26184398

Neighborhood context and youth cardiovascular health behaviors.

PubMed

Lee, Rebecca E; Cubbin, Catherine

2002-03-01

This study sought to determine the relationships between race/ethnicity, socioeconomic status (SES), and cardiovascular health behaviors among youths and whether neighborhood characteristics are associated with such behaviors independently of individual characteristics. Linear models determined the effects of individual and neighborhood characteristics (SES, social disorganization, racial/ethnic minority concentration, urbanization) on dietary habits, physical activity, and smoking among 8165 youths aged 12 to 21 years. Low SES was associated with poorer dietary habits, less physical activity, and higher odds of smoking. After adjustment for SES, Black race was associated with poorer dietary habits and lower odds of smoking. Hispanic ethnicity was associated with healthier dietary habits, lower levels of physical activity, and lower odds of smoking than non-Hispanic ethnicity. Low neighborhood SES and high neighborhood social disorganization were independently associated with poorer dietary habits, while high neighborhood Hispanic concentration and urbanicity were associated with healthier dietary habits. Neighborhood characteristics were not associated with physical activity or smoking. Changes in neighborhood social structures and policies that reduce social inequalities may enhance cardiovascular health behaviors.

Neighborhood Environments and Objectively Measured Physical Activity in 11 Countries

PubMed Central

Cerin, Ester; Cain, Kelli L; Conway, Terry L; Dyck, Delfien Van; Hinckson, Erica; Schipperijn, Jasper; Bourdeaudhuij, Ilse De; Owen, Neville; Davey, Rachel C; Hino, Adriano Akira Ferreira; Mitáš, Josef; Orzanco-Garralda, Rosario; Salvo, Deborah; Sarmiento, Olga L; Christiansen, Lars B; Macfarlane, Duncan J; Schofield, Grant; Sallis, James F

2014-01-01

Purpose Environmental changes are potentially effective population-level physical activity (PA) promotion strategies. However, robust multi-site evidence to guide international action for developing activity-supportive environments is lacking. We estimated pooled associations of perceived environmental attributes with objectively-measured PA outcomes; between-site differences in such associations; and, the extent to which perceived environmental attributes explain between-site differences in PA. Methods This was a cross-sectional study conducted in 16 cities located in Belgium, Brazil, Colombia, Czech Republic, Denmark, China, Mexico, New Zealand, Spain, United Kingdom, and USA. Participants were 6,968 adults residing in administrative units stratified by socio-economic status and transport-related walkability. Predictors were 10 perceived neighborhood environmental attributes. Outcome measures were accelerometry-assessed weekly minutes of moderate-to-vigorous PA (MVPA) and meeting the PA guidelines for cancer/weight gain prevention (420 min/week of MVPA). Results Most perceived neighborhood attributes were positively associated with the PA outcomes in the pooled, site-adjusted, single-predictor models. Associations were generalizable across geographical locations. Aesthetics and land use mix – access were significant predictors of both PA outcomes in the fully-adjusted models. Environmental attributes accounted for within-site variability in MVPA corresponding to a 3 min/d or 21 min/week standard deviation. Large between-site differences in PA outcomes were observed: 15.9% to 16.8% of these differences were explained by perceived environmental attributes. All neighborhood attributes were associated with between-site differences in the total effects of the perceived environment on PA outcomes. Conclusions Residents’ perceptions of neighborhood attributes that facilitate walking were positively associated with objectively-measured MVPA and meeting the guidelines

Language Experiences for Your Preschooler. Part 2: Activities in the Neighborhood.

ERIC Educational Resources Information Center

Tregaskis, George K.; And Others

This publication presents a curriculum designed to develop the communication skills of preschool children by introducing parents to a number of learning activities which might evolve from excursions in their neighborhoods and communities. The activities suggested are not closely, complicated, or overly time-consuming. In each section, background…

Examination of the neighborhood activation theory in normal and hearing-impaired listeners.

PubMed

Dirks, D D; Takayanagi, S; Moshfegh, A; Noffsinger, P D; Fausti, S A

2001-02-01

Experiments were conducted to examine the effects of lexical information on word recognition among normal hearing listeners and individuals with sensorineural hearing loss. The lexical factors of interest were incorporated in the Neighborhood Activation Model (NAM). Central to this model is the concept that words are recognized relationally in the context of other phonemically similar words. NAM suggests that words in the mental lexicon are organized into similarity neighborhoods and the listener is required to select the target word from competing lexical items. Two structural characteristics of similarity neighborhoods that influence word recognition have been identified; "neighborhood density" or the number of phonemically similar words (neighbors) for a particular target item and "neighborhood frequency" or the average frequency of occurrence of all the items within a neighborhood. A third lexical factor, "word frequency" or the frequency of occurrence of a target word in the language, is assumed to optimize the word recognition process by biasing the system toward choosing a high frequency over a low frequency word. Three experiments were performed. In the initial experiments, word recognition for consonant-vowel-consonant (CVC) monosyllables was assessed in young normal hearing listeners by systematically partitioning the items into the eight possible lexical conditions that could be created by two levels of the three lexical factors, word frequency (high and low), neighborhood density (high and low), and average neighborhood frequency (high and low). Neighborhood structure and word frequency were estimated computationally using a large, on-line lexicon-based Webster's Pocket Dictionary. From this program 400 highly familiar, monosyllables were selected and partitioned into eight orthogonal lexical groups (50 words/group). The 400 words were presented randomly to normal hearing listeners in speech-shaped noise (Experiment 1) and "in quiet" (Experiment 2) as

Neighborhood walkability and active travel (walking and cycling) in New York City.

PubMed

Freeman, Lance; Neckerman, Kathryn; Schwartz-Soicher, Ofira; Quinn, James; Richards, Catherine; Bader, Michael D M; Lovasi, Gina; Jack, Darby; Weiss, Christopher; Konty, Kevin; Arno, Peter; Viola, Deborah; Kerker, Bonnie; Rundle, Andrew G

2013-08-01

Urban planners have suggested that built environment characteristics can support active travel (walking and cycling) and reduce sedentary behavior. This study assessed whether engagement in active travel is associated with neighborhood walkability measured for zip codes in New York City. Data were analyzed on engagement in active travel and the frequency of walking or biking ten blocks or more in the past month, from 8,064 respondents to the New York City 2003 Community Health Survey (CHS). A neighborhood walkability scale that measures: residential, intersection, and subway stop density; land use mix; and the ratio of retail building floor area to retail land area was calculated for each zip code. Data were analyzed using zero-inflated negative binomial regression incorporating survey sample weights and adjusting for respondents' sociodemographic characteristics. Overall, 44 % of respondents reported no episodes of active travel and among those who reported any episode, the mean number was 43.2 episodes per month. Comparing the 75th to the 25th percentile of zip code walkability, the odds ratio for reporting zero episodes of active travel was 0.71 (95 % CI 0.61, 0.83) and the exponentiated beta coefficient for the count of episodes of active travel was 1.13 (95 % CI 1.06, 1.21). Associations between lower walkability and reporting zero episodes of active travel were significantly stronger for non-Hispanic Whites as compared to non-Hispanic Blacks and to Hispanics and for those living in higher income zip codes. The results suggest that neighborhood walkability is associated with higher engagement in active travel.

Walking mediates associations between neighborhood activity supportiveness and BMI in the Women’s Health Initiative San Diego cohort

PubMed Central

Remigio-Baker, Rosemay A.; Anderson, Cheryl A. M.; Adams, Marc A.; Norman, Gregory J.; Kerr, Jacqueline; Criqui, Michael H.; Allison, Matthew

2016-01-01

Objectives To investigate whether walking mediates neighborhood built environment associations with weight status in middle- and older-aged women. Methods Participants (N=5085; mean age=64±7.7; 75.4% White non-Hispanic) were from the Women’s Health Initiative San Diego cohort baseline visits. Body mass index (BMI) and waist circumference were measured objectively. Walking was assessed via survey. The geographic information system (GIS)-based home neighborhood activity supportiveness index included residential density, street connectivity, land use mix, and number of parks. Results BMI was 0.22 units higher and the odds ratio for being obese (vs. normal or overweight) was 8% higher for every standard deviation decrease in neighborhood activity supportiveness. Walking partially mediated these associations (22–23% attenuation). Findings were less robust for waist circumference. Conclusions Findings suggest women who lived in activity-supportive neighborhoods had a lower BMI than their counterparts, in part because they walked more. Improving neighborhood activity supportiveness has population-level implications for improving weight status and health. PMID:26798961

Associations Between Family Support, Family Intimacy, and Neighborhood Violence and Physical Activity in Urban Adolescent Girls

PubMed Central

Kuo, JoAnn; Voorhees, Carolyn C.; Haythornthwaite, Jennifer A.; Young, Deborah Rohm

2007-01-01

We examined the association between various dimensions of the family environment, including family intimacy and involvement in activities, family support for physical activity, and neighborhood violence (perceived and objective) and physical activity among urban, predominantly African American, ninth-grade girls in Balti-more, Md. Greater family intimacy (P = .05) and support (P = .01), but not neighborhood violence, was associated with physical activity. Family factors, including family intimacy and support, are potential targets in physical activity interventions for urban high-school girls. PMID:17138926

Wave activity in the neighborhood of the bowshock of Mars

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

Sagdeev, R.Z.; Shapiro, V.D.; Shevchenko, V.I.

Plasma wave activity in the neighborhood of the Martial bow shock were measured for the first time by the Soviet spacecraft Phobos-2 in a wide frequency range from dc to 150 kHz. The wave activity varied in character as the spacecraft moved across different plasma regions: in the neighborhood of the Martian bow shock, inside the magnetosheath and in the tail region. In this paper the authors provide suggestions for the processes responsible for these plasma waves. The most interesting peculiarities of the wave activity around Mars is the sharp increase of wave intensity in the magnetosheath region. This increasemore » is attributed to two different physical mechanisms. High frequency waves are excited at the shock front due to currents flowing along the front; these ion acoustic waves are convected inside by the solar wind. The low frequency waves ({approximately}100 Hz) close to the inside boundary were, they believe, generated by heavy Martian ions diffusing through the planetopause into the magnetosheath.« less

"Who Should Have the Neighborhood?" Children's Ideas about the Future Development of an Aging Neighborhood. [And] Moscow, Blueprint for a City: The Only Really Planned City in the World! Instructional Activities Series.

ERIC Educational Resources Information Center

Bishop, John E.; And Others

Two elementary-grade activities on geography are combined. The first activity employs a group discussion approach to investigate neighborhoods and residences. Given data about a neighborhood area in Houston, students make predictions and express feelings about future developments in the area. The second activity investigates urban planning in…

Contour-based image warping

NASA Astrophysics Data System (ADS)

Chan, Kwai H.; Lau, Rynson W.

1996-09-01

Image warping concerns about transforming an image from one spatial coordinate to another. It is widely used for the vidual effect of deforming and morphing images in the film industry. A number of warping techniques have been introduced, which are mainly based on the corresponding pair mapping of feature points, feature vectors or feature patches (mostly triangular or quadrilateral). However, very often warping of an image object with an arbitrary shape is required. This requires a warping technique which is based on boundary contour instead of feature points or feature line-vectors. In addition, when feature point or feature vector based techniques are used, approximation of the object boundary by using point or vectors is required. In this case, the matching process of the corresponding pairs will be very time consuming if a fine approximation is required. In this paper, we propose a contour-based warping technique for warping image objects with arbitrary shapes. The novel idea of the new method is the introduction of mathematical morphology to allow a more flexible control of image warping. Two morphological operators are used as contour determinators. The erosion operator is used to warp image contents which are inside a user specified contour while the dilation operation is used to warp image contents which are outside of the contour. This new method is proposed to assist further development of a semi-automatic motion morphing system when accompanied with robust feature extractors such as deformable template or active contour model.

A complete system for head tracking using motion-based particle filter and randomly perturbed active contour

NASA Astrophysics Data System (ADS)

Bouaynaya, N.; Schonfeld, Dan

2005-03-01

Many real world applications in computer and multimedia such as augmented reality and environmental imaging require an elastic accurate contour around a tracked object. In the first part of the paper we introduce a novel tracking algorithm that combines a motion estimation technique with the Bayesian Importance Sampling framework. We use Adaptive Block Matching (ABM) as the motion estimation technique. We construct the proposal density from the estimated motion vector. The resulting algorithm requires a small number of particles for efficient tracking. The tracking is adaptive to different categories of motion even with a poor a priori knowledge of the system dynamics. Particulary off-line learning is not needed. A parametric representation of the object is used for tracking purposes. In the second part of the paper, we refine the tracking output from a parametric sample to an elastic contour around the object. We use a 1D active contour model based on a dynamic programming scheme to refine the output of the tracker. To improve the convergence of the active contour, we perform the optimization over a set of randomly perturbed initial conditions. Our experiments are applied to head tracking. We report promising tracking results in complex environments.

Associations of neighborhood characteristics with active park use: an observational study in two cities in the USA and Belgium

PubMed Central

2013-01-01

Background Public parks can be an important setting for physical activity promotion, but to increase park use and the activity levels of park users, the crucial attributes related to active park use need to be defined. Not only user characteristics and structural park attributes, but also characteristics of the surrounding neighborhood are important to examine. Furthermore, internationally comparable studies are needed, to find out if similar intervention strategies might be effective worldwide. The main aim of this study was to examine whether the overall number of park visitors and their activity levels depend on study site, neighborhood walkability and neighborhood income. Methods Data were collected in 20 parks in Ghent, Belgium and San Diego, USA. Two trained observers systematically coded park characteristics using the Environmental Assessment of Public Recreation Spaces (EAPRS) tool, and park user characteristics using the System for Observing Play and recreation in Communities (SOPARC) tool. Multilevel multiple regression models were conducted in MLwiN 2.25. Results In San Diego parks, activity levels of park visitors and number of vigorously active visitors were higher than in Ghent, while the number of visitors walking and the overall number of park visitors were lower. Neighborhood walkability was positively associated with the overall number of visitors, the number of visitors walking, number of sedentary visitors and mean activity levels of visitors. Neighborhood income was positively associated with the overall number of visitors, but negatively with the number of visitors being vigorously active. Conclusions Neighborhood characteristics are important to explain park use. Neighborhood walkability-related attributes should be taken into account when promoting the use of existing parks or creating new parks. Because no strong differences were found between parks in high- and low-income neighborhoods, it seems that promoting park use might be a promising

Lymph node segmentation by dynamic programming and active contours.

PubMed

Tan, Yongqiang; Lu, Lin; Bonde, Apurva; Wang, Deling; Qi, Jing; Schwartz, Lawrence H; Zhao, Binsheng

2018-03-03

Enlarged lymph nodes are indicators of cancer staging, and the change in their size is a reflection of treatment response. Automatic lymph node segmentation is challenging, as the boundary can be unclear and the surrounding structures complex. This work communicates a new three-dimensional algorithm for the segmentation of enlarged lymph nodes. The algorithm requires a user to draw a region of interest (ROI) enclosing the lymph node. Rays are cast from the center of the ROI, and the intersections of the rays and the boundary of the lymph node form a triangle mesh. The intersection points are determined by dynamic programming. The triangle mesh initializes an active contour which evolves to low-energy boundary. Three radiologists independently delineated the contours of 54 lesions from 48 patients. Dice coefficient was used to evaluate the algorithm's performance. The mean Dice coefficient between computer and the majority vote results was 83.2%. The mean Dice coefficients between the three radiologists' manual segmentations were 84.6%, 86.2%, and 88.3%. The performance of this segmentation algorithm suggests its potential clinical value for quantifying enlarged lymph nodes. © 2018 American Association of Physicists in Medicine.

The Role of Neighborhood Ecological Assets and Activity Involvement in Youth Developmental Outcomes: Differential Impacts of Asset Poor and Asset Rich Neighborhoods

ERIC Educational Resources Information Center

Urban, Jennifer Brown; Lewin-Bizan, Selva; Lerner, Richard M.

2009-01-01

Developmental system theories recognize that variables from multiple levels of organization within the bioecology of human development contribute to adolescent development, including individual factors, family factors and the neighborhood which includes extracurricular activities. Extracurricular activities provide a context for youth development,…

Computer aided weld defect delineation using statistical parametric active contours in radiographic inspection.

PubMed

Goumeidane, Aicha Baya; Nacereddine, Nafaa; Khamadja, Mohammed

2015-01-01

A perfect knowledge of a defect shape is determinant for the analysis step in automatic radiographic inspection. Image segmentation is carried out on radiographic images and extract defects indications. This paper deals with weld defect delineation in radiographic images. The proposed method is based on a new statistics-based explicit active contour. An association of local and global modeling of the image pixels intensities is used to push the model to the desired boundaries. Furthermore, other strategies are proposed to accelerate its evolution and make the convergence speed depending only on the defect size as selecting a band around the active contour curve. The experimental results are very promising, since experiments on synthetic and radiographic images show the ability of the proposed model to extract a piece-wise homogenous object from very inhomogeneous background, even in a bad quality image.

Robust active contour via additive local and global intensity information based on local entropy

NASA Astrophysics Data System (ADS)

Yuan, Shuai; Monkam, Patrice; Zhang, Feng; Luan, Fangjun; Koomson, Ben Alfred

2018-01-01

Active contour-based image segmentation can be a very challenging task due to many factors such as high intensity inhomogeneity, presence of noise, complex shape, weak boundaries objects, and dependence on the position of the initial contour. We propose a level set-based active contour method to segment complex shape objects from images corrupted by noise and high intensity inhomogeneity. The energy function of the proposed method results from combining the global intensity information and local intensity information with some regularization factors. First, the global intensity term is proposed based on a scheme formulation that considers two intensity values for each region instead of one, which outperforms the well-known Chan-Vese model in delineating the image information. Second, the local intensity term is formulated based on local entropy computed considering the distribution of the image brightness and using the generalized Gaussian distribution as the kernel function. Therefore, it can accurately handle high intensity inhomogeneity and noise. Moreover, our model is not dependent on the position occupied by the initial curve. Finally, extensive experiments using various images have been carried out to illustrate the performance of the proposed method.

Intrinsic Bayesian Active Contours for Extraction of Object Boundaries in Images

PubMed Central

Srivastava, Anuj

2010-01-01

We present a framework for incorporating prior information about high-probability shapes in the process of contour extraction and object recognition in images. Here one studies shapes as elements of an infinite-dimensional, non-linear quotient space, and statistics of shapes are defined and computed intrinsically using differential geometry of this shape space. Prior models on shapes are constructed using probability distributions on tangent bundles of shape spaces. Similar to the past work on active contours, where curves are driven by vector fields based on image gradients and roughness penalties, we incorporate the prior shape knowledge in the form of vector fields on curves. Through experimental results, we demonstrate the use of prior shape models in the estimation of object boundaries, and their success in handling partial obscuration and missing data. Furthermore, we describe the use of this framework in shape-based object recognition or classification. PMID:21076692

Obesogenic Neighborhood Environments, Child and Parent Obesity

PubMed Central

Saelens, Brian E.; Sallis, James F.; Frank, Lawrence D.; Couch, Sarah C.; Zhou, Chuan; Colburn, Trina; Cain, Kelli L.; Chapman, James; Glanz, Karen

2012-01-01

Background Identifying neighborhood environment attributes related to childhood obesity can inform environmental changes for obesity prevention. Purpose To evaluate child and parent weight status across neighborhoods in King County/Seattle and San Diego County differing in GIS-defined physical activity environment (PAE) and nutrition environment (NE) characteristics. Methods Neighborhoods were selected to represent high (favorable) versus low (unfavorable) on the two measures, forming four neighborhood types (low on both measures, low PAE/high NE, high PAE/low NE, and high on both measures). Weight and height of children aged 6–11 years and one parent (n=730) from selected neighborhoods were assessed in 2007–2009. Differences in child and parent overweight and obesity by neighborhood type were examined, adjusting for neighborhood-, family-, and individual-level demographics. Results Children from neighborhoods high on both environment measures were less likely to be obese (7.7% vs 15.9% OR=0.44, p=0.02) and marginally less likely to be overweight (23.7% vs 31.7%; OR=0.67, p=0.08) than children from neighborhoods low on both measures. In models adjusted for parent weight status and demographic factors, neighborhood environment type remained related to child obesity (high vs low on both measures; OR=0.41, p<0.03). Parents in neighborhoods high on both measures (versus low on both) were marginally less likely to be obese (20.1% vs 27.7%; OR=0.66; p=0.08), although parent overweight did not differ on this variable. The lower odds of parent obesity in neighborhoods with environments supportive of physical activity and healthy eating remained in models adjusted for demographics (high vs low on the environment measures; OR=0.57, p=0.053). Conclusions Findings support the proposed GIS-based definitions of obesogenic neighborhoods for children and parents that consider both physical activity and nutrition environment features. PMID:22516504

Neighborhood organization activities: evacuation drills, clusters, and fire safety awareness

Treesearch

Dick White

1995-01-01

Emergency preparedness activities of one Berkeley-Oakland Hills neighborhood at the wildland/urban interface include establishing clusters that reduce fire hazards and fuel loads, setting aside emergency supplies, and identifying evacuation routes; taking emergency preparedness courses from the Offices of Emergency Services of Berkeley and Oakland (the CERT and CORE...

Building a National Neighborhood Dataset From Geotagged Twitter Data for Indicators of Happiness, Diet, and Physical Activity.

PubMed

Nguyen, Quynh C; Li, Dapeng; Meng, Hsien-Wen; Kath, Suraj; Nsoesie, Elaine; Li, Feifei; Wen, Ming

2016-10-17

Studies suggest that where people live, play, and work can influence health and well-being. However, the dearth of neighborhood data, especially data that is timely and consistent across geographies, hinders understanding of the effects of neighborhoods on health. Social media data represents a possible new data resource for neighborhood research. The aim of this study was to build, from geotagged Twitter data, a national neighborhood database with area-level indicators of well-being and health behaviors. We utilized Twitter's streaming application programming interface to continuously collect a random 1% subset of publicly available geolocated tweets for 1 year (April 2015 to March 2016). We collected 80 million geotagged tweets from 603,363 unique Twitter users across the contiguous United States. We validated our machine learning algorithms for constructing indicators of happiness, food, and physical activity by comparing predicted values to those generated by human labelers. Geotagged tweets were spatially mapped to the 2010 census tract and zip code areas they fall within, which enabled further assessment of the associations between Twitter-derived neighborhood variables and neighborhood demographic, economic, business, and health characteristics. Machine labeled and manually labeled tweets had a high level of accuracy: 78% for happiness, 83% for food, and 85% for physical activity for dichotomized labels with the F scores 0.54, 0.86, and 0.90, respectively. About 20% of tweets were classified as happy. Relatively few terms (less than 25) were necessary to characterize the majority of tweets on food and physical activity. Data from over 70,000 census tracts from the United States suggest that census tract factors like percentage African American and economic disadvantage were associated with lower census tract happiness. Urbanicity was related to higher frequency of fast food tweets. Greater numbers of fast food restaurants predicted higher frequency of fast

Building a National Neighborhood Dataset From Geotagged Twitter Data for Indicators of Happiness, Diet, and Physical Activity

PubMed Central

Li, Dapeng; Meng, Hsien-Wen; Kath, Suraj; Nsoesie, Elaine; Li, Feifei; Wen, Ming

2016-01-01

Background Studies suggest that where people live, play, and work can influence health and well-being. However, the dearth of neighborhood data, especially data that is timely and consistent across geographies, hinders understanding of the effects of neighborhoods on health. Social media data represents a possible new data resource for neighborhood research. Objective The aim of this study was to build, from geotagged Twitter data, a national neighborhood database with area-level indicators of well-being and health behaviors. Methods We utilized Twitter’s streaming application programming interface to continuously collect a random 1% subset of publicly available geolocated tweets for 1 year (April 2015 to March 2016). We collected 80 million geotagged tweets from 603,363 unique Twitter users across the contiguous United States. We validated our machine learning algorithms for constructing indicators of happiness, food, and physical activity by comparing predicted values to those generated by human labelers. Geotagged tweets were spatially mapped to the 2010 census tract and zip code areas they fall within, which enabled further assessment of the associations between Twitter-derived neighborhood variables and neighborhood demographic, economic, business, and health characteristics. Results Machine labeled and manually labeled tweets had a high level of accuracy: 78% for happiness, 83% for food, and 85% for physical activity for dichotomized labels with the F scores 0.54, 0.86, and 0.90, respectively. About 20% of tweets were classified as happy. Relatively few terms (less than 25) were necessary to characterize the majority of tweets on food and physical activity. Data from over 70,000 census tracts from the United States suggest that census tract factors like percentage African American and economic disadvantage were associated with lower census tract happiness. Urbanicity was related to higher frequency of fast food tweets. Greater numbers of fast food

Does the neighborhood context alter the link between youth's after-school time activities and developmental outcomes? A multilevel analysis.

PubMed

Fauth, Rebecca C; Roth, Jodie L; Brooks-Gunn, Jeanne

2007-05-01

This article examines links between different measures of after-school time activity participation (5 specific activities and breadth) on youth's developmental outcomes (anxiety/depression, delinquency, and substance use) over 6 years and whether these links are moderated by neighborhood-level variables. The sample (N=1,315) of 9- and 12-year-old youth was drawn from the Project on Human Development in Chicago Neighborhoods (PHDCN), a multilevel, longitudinal study of youth from 80 Chicago neighborhoods. Findings revealed that different types of activities and patterns of participation over time were associated with outcomes for youth and that, to some extent, these outcomes varied with neighborhood characteristics. In brief, sports participation was associated with fewer anxious/depressed symptoms, higher average delinquency scores, and increased substance use-both average scores and growth over time. Participation in the arts and student government were negatively associated with average substance use and attenuated increases in usage over time. Participation in community-based clubs was positively associated with youth's anxiety/depression in violent neighborhoods only, whereas church groups were protective against substance use in nonviolent neighborhoods. The direction of the influence of breadth of participation was nonlinear for delinquency such that delinquency scores were highest among youth who engaged in an average number of activities. Copyright (c) 2007 APA, all rights reserved.

Creation of digital contours that approach the characteristics of cartographic contours

USGS Publications Warehouse

Tyler, Dean J.; Greenlee, Susan K.

2012-01-01

The capability to easily create digital contours using commercial off-the-shelf (COTS) software has existed for decades. Out-of-the-box raw contours are suitable for many scientific applications without pre- or post-processing; however, cartographic applications typically require additional improvements. For example, raw contours generally require smoothing before placement on a map. Cartographic contours must also conform to certain spatial/logical rules; for example, contours may not cross waterbodies. The objective was to create contours that match as closely as possible the cartographic contours produced by manual methods on the 1:24,000-scale, 7.5-minute Topographic Map series. This report outlines the basic approach, describes a variety of problems that were encountered, and discusses solutions. Many of the challenges described herein were the result of imperfect input raster elevation data and the requirement to have the contours integrated with hydrographic features from the National Hydrography Dataset (NHD).

Fractal active contour model for segmenting the boundary of man-made target in nature scenes

NASA Astrophysics Data System (ADS)

Li, Min; Tang, Yandong; Wang, Lidi; Shi, Zelin

2006-02-01

In this paper, a novel geometric active contour model based on the fractal dimension feature to extract the boundary of man-made target in nature scenes is presented. In order to suppress the nature clutters, an adaptive weighting function is defined using the fractal dimension feature. Then the weighting function is introduced into the geodesic active contour model to detect the boundary of man-made target. Curve driven by our proposed model can evolve gradually from the initial position to the boundary of man-made target without being disturbed by nature clutters, even if the initial curve is far away from the true boundary. Experimental results validate the effectiveness and feasibility of our model.

Associations of perceived neighborhood physical and social environments with physical activity and television viewing in African American men and women

PubMed Central

Strong, Larkin L.; Reitzel, Lorraine R.; Wetter, David W.; McNeill, Lorna H.

2013-01-01

Purpose Few studies have assessed how attributes of neighborhood environments contribute to sedentary, in addition to active, behaviors. This study investigated associations of perceived social and physical aspects of neighborhood environments with television (TV) viewing and physical activity (PA) in African American adults. Design Cross-sectional analysis of self-reported survey. Setting Large mega-church in Houston, TX. Subjects 1,374 African American men and women. Measures Outcomes included log-transformed daily TV viewing and participation in medium/high levels of PA, measured by the short version of the International Physical Activity Questionnaire. Neighborhood perceptions were assessed with the Social Cohesion and Trust and the Neighborhood Problems scales. Analysis Multivariable models that controlled for clustering within neighborhoods. Results Reporting more neighborhood problems was significantly associated with greater log-transformed TV viewing in women (β=0.017, SE=0.006, p=0.003), and social cohesion was positively associated with PA in women (OR=1.06, 95% CI=1.02, 1.11, p=0.006). Concerns about litter and walking after dark, and a lack of places to shop were associated with increased TV viewing among women, and concerns about traffic and walking after dark were associated with reduced PA among men. Conclusion Physical and social neighborhood conditions were associated with TV viewing and PA, particularly in women. Neighborhood-based strategies to reduce sedentary behaviors and enhance PA should include attention to social as well as physical aspects of neighborhood environments. PMID:23398134

Associations of perceived neighborhood physical and social environments with physical activity and television viewing in African-American men and women.

PubMed

Strong, Larkin L; Reitzel, Lorraine R; Wetter, David W; McNeill, Lorna H

2013-01-01

Few studies have assessed how attributes of neighborhood environments contribute to sedentary, in addition to active, behaviors. This study investigated associations of perceived social and physical aspects of neighborhood environments with television (TV) viewing and physical activity (PA) in African-American adults. Cross-sectional analysis of self-reported survey. Large mega-church in Houston, Texas. A total of 1374 African-American men and women. Outcomes included log-transformed daily TV viewing and participation in medium/high levels of PA, measured by the short version of the International Physical Activity Questionnaire. Neighborhood perceptions were assessed with the Social Cohesion and Trust and the Neighborhood Problems scales. Multivariable models that controlled for clustering within neighborhoods. Reporting more neighborhood problems was significantly associated with greater log-transformed TV viewing in women (β = .017, SE = .006, p = .003), and social cohesion was positively associated with PA in women (odds ratio = 1.06, 95% confidence interval = 1.02, 1.11, p = .006). Concerns about litter and walking after dark and a lack of places to shop were associated with increased TV viewing among women, and concerns about traffic and walking after dark were associated with reduced PA among men. Physical and social neighborhood conditions were associated with TV viewing and PA, particularly in women. Neighborhood-based strategies to reduce sedentary behaviors and enhance PA should include attention to social as well as physical aspects of neighborhood environments.

Contouring variability of human- and deformable-generated contours in radiotherapy for prostate cancer

NASA Astrophysics Data System (ADS)

Gardner, Stephen J.; Wen, Ning; Kim, Jinkoo; Liu, Chang; Pradhan, Deepak; Aref, Ibrahim; Cattaneo, Richard, II; Vance, Sean; Movsas, Benjamin; Chetty, Indrin J.; Elshaikh, Mohamed A.

2015-06-01

This study was designed to evaluate contouring variability of human-and deformable-generated contours on planning CT (PCT) and CBCT for ten patients with low-or intermediate-risk prostate cancer. For each patient in this study, five radiation oncologists contoured the prostate, bladder, and rectum, on one PCT dataset and five CBCT datasets. Consensus contours were generated using the STAPLE method in the CERR software package. Observer contours were compared to consensus contour, and contour metrics (Dice coefficient, Hausdorff distance, Contour Distance, Center-of-Mass [COM] Deviation) were calculated. In addition, the first day CBCT was registered to subsequent CBCT fractions (CBCTn: CBCT2-CBCT5) via B-spline Deformable Image Registration (DIR). Contours were transferred from CBCT1 to CBCTn via the deformation field, and contour metrics were calculated through comparison with consensus contours generated from human contour set. The average contour metrics for prostate contours on PCT and CBCT were as follows: Dice coefficient—0.892 (PCT), 0.872 (CBCT-Human), 0.824 (CBCT-Deformed); Hausdorff distance—4.75 mm (PCT), 5.22 mm (CBCT-Human), 5.94 mm (CBCT-Deformed); Contour Distance (overall contour)—1.41 mm (PCT), 1.66 mm (CBCT-Human), 2.30 mm (CBCT-Deformed); COM Deviation—2.01 mm (PCT), 2.78 mm (CBCT-Human), 3.45 mm (CBCT-Deformed). For human contours on PCT and CBCT, the difference in average Dice coefficient between PCT and CBCT (approx. 2%) and Hausdorff distance (approx. 0.5 mm) was small compared to the variation between observers for each patient (standard deviation in Dice coefficient of 5% and Hausdorff distance of 2.0 mm). However, additional contouring variation was found for the deformable-generated contours (approximately 5.0% decrease in Dice coefficient and 0.7 mm increase in Hausdorff distance relative to human-generated contours on CBCT). Though deformable contours provide a reasonable starting point for contouring on

A retrospective study on changes in residents' physical activities, social interactions, and neighborhood cohesion after moving to a walkable community.

PubMed

Zhu, Xuemei; Yu, Chia-Yuan; Lee, Chanam; Lu, Zhipeng; Mann, George

2014-12-01

This study is to examine changes in residents' physical activities, social interactions, and neighborhood cohesion after they moved to a walkable community in Austin, Texas. Retrospective surveys (N=449) were administered in 2013-2014 to collect pre- and post-move data about the outcome variables and relevant personal, social, and physical environmental factors. Walkability of each resident's pre-move community was measured using the Walk Score. T tests were used to examine the pre-post move differences in the outcomes in the whole sample and across sub-groups with different physical activity levels, neighborhood conditions, and neighborhood preferences before the move. After the move, total physical activity increased significantly in the whole sample and all sub-groups except those who were previously sufficiently active; lived in communities with high walkability, social interactions, or neighborhood cohesion; or had moderate preference for walkable neighborhoods. Walking in the community increased in the whole sample and all subgroups except those who were previously sufficiently active, moved from high-walkability communities, or had little to no preference for walkable neighborhoods. Social interactions and neighborhood cohesion increased significantly after the move in the whole sample and all sub-groups. This study explored potential health benefits of a walkable community in promoting physically and socially active lifestyles, especially for populations at higher risk of obesity. The initial result is promising, suggesting the need for more work to further examine the relationships between health and community design using pre-post assessments. Copyright © 2014 Elsevier Inc. All rights reserved.

Neighborhood, route, and school environments and children's active commuting.

PubMed

Panter, Jenna R; Jones, Andrew P; Van Sluijs, Esther M F; Griffin, Simon J

2010-03-01

Walking and cycling to school represent an opportunity for children to achieve regular physical activity. These behaviors may be influenced by characteristics of the environment around homes and schools, yet few studies have quantified the potential associations between these two sets of factors. This study aims to assess whether objectively measured characteristics of the neighborhood, route, and school environments are associated with active commuting to school among children, and it explores whether distance acts as a moderator in this association. A cross-sectional study was conducted of 2012 children (899 boys and 1113 girls) aged 9-10 years attending 92 schools in the county of Norfolk, United Kingdom. Questionnaires were completed by children and parents during Summer 2007. Attributes around the home and children's route to school were assessed using a GIS. School environments were assessed using a newly developed school audit and via questionnaires completed by head teachers. Data were analyzed in 2008. Almost half of the children usually walked or cycled to school. Children who lived in a more deprived area and whose route to school was direct were less likely to walk or cycle to school, whereas those who had a higher density of roads in their neighborhood were more likely to walk. Further, children whose routes had a high density of streetlights were less likely to cycle to school. Distance did not moderate the observed associations. Objectively measured neighborhood and route factors are associated with walking and cycling to school. However, distance did not moderate the associations found here. Creating safe environments by improving urban design may influence children's commuting behavior. Intervention studies are needed to confirm the findings from this observational cross-sectional study. Copyright (c) 2010 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

Neighborhood cohesion, neighborhood disorder, and cardiometabolic risk.

PubMed

Robinette, Jennifer W; Charles, Susan T; Gruenewald, Tara L

2018-02-01

Perceptions of neighborhood disorder (trash, vandalism) and cohesion (neighbors trust one another) are related to residents' health. Affective and behavioral factors have been identified, but often in studies using geographically select samples. We use a nationally representative sample (n = 9032) of United States older adults from the Health and Retirement Study to examine cardiometabolic risk in relation to perceptions of neighborhood cohesion and disorder. Lower cohesion is significantly related to greater cardiometabolic risk in 2006/2008 and predicts greater risk four years later (2010/2012). The longitudinal relation is partially accounted for by anxiety and physical activity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Neighborhood environment and children's physical activity and body mass index: evidence from military personnel installation assignments.

PubMed

Datar, Ashlesha; Nicosia, Nancy; Wong, Elizabeth; Shier, Victoria

2015-04-01

The majority of existing studies use observed, rather than experimental or quasi-experimental, variation in individuals' neighborhood environments to study their influence on body weight and related behaviors. This study leverages the periodic relocation of military personnel to examine the relationship between neighborhood environment and children's physical activity (PA) and BMI in military families. This study utilizes data on 12- and 13-year-old children from the Military Teenagers Environments, Exercise, and Nutrition Study (N=903). Multivariate regression models are estimated, separately for families living on- and off-post, to examine the relationship between parents' perceptions of the neighborhood environment, measured using the Neighborhood Environment Walkability Scale-Youth Version (NEWS-Y), and children's self-reported PA and BMI. Different features of the neighborhood environment were significant for off- versus on-post families. For children living off-post, a 1 standard deviation (SD) increase in the proximity-to-recreational-facilities subscale was associated with 16.5 additional minutes per week (p<0.05) of moderate PA (MPA), but street connectivity had a significant negative association with vigorous activity. For children living on-post, a 1 SD increase on the crime safety subscale was associated with 22.9 additional minutes per week (p<0.05) of MPA. None of the NEWS-Y subscales were associated with children's BMI. Efforts to increase children's PA in military families should take into account that different aspects of the neighborhood environment matter for children living on- versus off-post.

A Longitudinal Analysis of the Influence of the Neighborhood Environment on Recreational Walking within the Neighborhood: Results from RESIDE

PubMed Central

Knuiman, Matthew; Divitini, Mark; Foster, Sarah; Hooper, Paula; Boruff, Bryan; Bull, Fiona; Giles-Corti, Billie

2017-01-01

Background: There is limited longitudinal evidence confirming the role of neighborhood environment attributes in encouraging people to walk more or if active people simply choose to live in activity-friendly neighborhoods. Natural experiments of policy changes to create more walkable communities provide stronger evidence for a causal effect of neighborhood environments on residents’ walking. Objectives: We aimed to investigate longitudinal associations between objective and perceived neighborhood environment measures and neighborhood recreational walking. Methods: We analyzed longitudinal data collected over 8 yr (four surveys) from the RESIDential Environments (RESIDE) Study (Perth, Australia, 2003–2012). At each time point, participants reported the frequency and total minutes of recreational walking/week within their neighborhood and neighborhood environment perceptions. Objective measures of the neighborhood environment were generated using a Geographic Information System (GIS). Results: Local recreational walking was influenced by objectively measured access to a medium-/large-size park, beach access, and higher street connectivity, which was reduced when adjusted for neighborhood perceptions. In adjusted models, positive perceptions of access to a park and beach, higher street connectivity, neighborhood esthetics, and safety from crime were independent determinants of increased neighborhood recreational walking. Local recreational walking increased by 9 min/wk (12% increase in frequency) for each additional perceived neighborhood attribute present. Conclusions: Our findings provide urban planners and policy makers with stronger causal evidence of the positive impact of well-connected neighborhoods and access to local parks of varying sizes on local residents’ recreational walking and health. https://doi.org/10.1289/EHP823 PMID:28728139

Convolutional virtual electric field for image segmentation using active contours.

PubMed

Wang, Yuanquan; Zhu, Ce; Zhang, Jiawan; Jian, Yuden

2014-01-01

Gradient vector flow (GVF) is an effective external force for active contours; however, it suffers from heavy computation load. The virtual electric field (VEF) model, which can be implemented in real time using fast Fourier transform (FFT), has been proposed later as a remedy for the GVF model. In this work, we present an extension of the VEF model, which is referred to as CONvolutional Virtual Electric Field, CONVEF for short. This proposed CONVEF model takes the VEF model as a convolution operation and employs a modified distance in the convolution kernel. The CONVEF model is also closely related to the vector field convolution (VFC) model. Compared with the GVF, VEF and VFC models, the CONVEF model possesses not only some desirable properties of these models, such as enlarged capture range, u-shape concavity convergence, subject contour convergence and initialization insensitivity, but also some other interesting properties such as G-shape concavity convergence, neighboring objects separation, and noise suppression and simultaneously weak edge preserving. Meanwhile, the CONVEF model can also be implemented in real-time by using FFT. Experimental results illustrate these advantages of the CONVEF model on both synthetic and natural images.

What is in a contour map? A region-based logical formalization of contour semantics

USGS Publications Warehouse

Usery, E. Lynn; Hahmann, Torsten

2015-01-01

This paper analyses and formalizes contour semantics in a first-order logic ontology that forms the basis for enabling computational common sense reasoning about contour information. The elicited contour semantics comprises four key concepts – contour regions, contour lines, contour values, and contour sets – and their subclasses and associated relations, which are grounded in an existing qualitative spatial ontology. All concepts and relations are illustrated and motivated by physical-geographic features identifiable on topographic contour maps. The encoding of the semantics of contour concepts in first-order logic and a derived conceptual model as basis for an OWL ontology lay the foundation for fully automated, semantically-aware qualitative and quantitative reasoning about contours.

A Walk (or Cycle) to the Park: Active Transit to Neighborhood Amenities, the CARDIA Study

PubMed Central

Boone-Heinonen, Janne; Jacobs, David R.; Sidney, Stephen; Sternfeld, Barbara; Lewis, Cora E.; Gordon-Larsen, Penny

2009-01-01

Background Building on known associations between active commuting and reduced cardiovascular disease (CVD) risk, this study examines active transit to neighborhood amenities and differences between walking versus cycling for transportation. Method Year 20 data from the Coronary Artery Risk Development in Young Adults (CARDIA) study (3549 black and white adults aged 38–50 years in 2005–06) were analyzed in 2008–2009. Sociodemographic correlates of transportation mode (car-only, walk-only, any cycling, other) to neighborhood amenities were examined in multivariable multinomial logistic models. Gender-stratified, multivariable linear or multinomial regression models compared CVD risk factors across transit modes. Results Active transit was most common to parks and public transit stops; walking was more common than cycling. Among those who used each amenity, active transit (walk-only and any cycling versus car-only transit) was more common in men and those with no live-in partner and less than full-time employment [significant OR's (95% CI) ranging from 1.56 (1.08, 2.27) to 4.52 (1.70, 12.14)], and less common in those with children. Active transit to any neighborhood amenity was associated with more favorable BMI, waist circumference, and fitness [largest coefficient (95% CI) −1.68 (−2.81, −0.55) for BMI, −3.41 (−5.71, −1.11) for waist circumference (cm), and 36.65 (17.99, 55.31) for treadmill test duration (sec)]. Only cycling was associated with lower lifetime CVD risk classification. Conclusion Active transit to neighborhood amenities was related to sociodemographics and CVD risk factors. Variation in health-related benefits by active transit mode, if validated in prospective studies, may have implications for transportation planning and research. PMID:19765499

Neighborhood Disadvantage and Physical Function: The Contributions of Neighborhood-Level Perceptions of Safety From Crime and Walking for Recreation.

PubMed

Loh, Venurs H Y; Rachele, Jerome N; Brown, Wendy J; Ghani, Fatima; Turrell, Gavin

2018-04-20

Residents of more socioeconomically disadvantaged neighborhoods are more likely to report poorer physical function, although the reasons for this remain unknown. It is possible that neighborhood-level perceptions of safety from crime contribute to this relationship through its association with walking for recreation. Data were obtained from the fourth wave (collected in 2013) of the HABITAT (How Areas in Brisbane Influence HealTh and AcTivity) multilevel longitudinal study of middle- to older-aged adults (46-74 y) residing in 200 neighborhoods in Brisbane, Australia. The data were analyzed separately for men (n = 2190) and women (n = 2977) using multilevel models. Residents of the most disadvantaged neighborhoods had poorer physical function, perceived their neighborhoods to be less safe from crime, and do less walking for recreation. These factors accounted for differences in physical function between disadvantaged and advantaged neighborhoods (24% for men and 25% for women). This study highlights the importance of contextual characteristics, through their associations with behaviors, that can have in explaining the relationship between neighborhood disadvantage and physical function. Interventions aimed at improving neighborhood safety integrated with supportive environments for physical activity may have positive impact on physical function among all socioeconomic groups.

Active Contours for Multispectral Images With Non-Homogeneous Sub-Regions

DTIC Science & Technology

2005-09-16

Marching Methods. Cambridge Monographs on Applied and Computational Mathematics, Cambridge University Press, 2nd ed., 1999. [76] R . Malladi and J. Sethian...F. Dibos, “A geometric model for active contours,” Numerische Mathematik, p. 19, 1993. [80] R . Malladi , J. Sethian, and C. Vemuri, “Shape modeling... Malladi et al. [80, 76] proposed a similar model given by ∂φ(x, y) ∂t = g(I(x, y))(κ(φ(x, y)) + ν)|∇φ(x, y)|, (3.14) where g(·) : Ω → < denotes the

Neighborhood Environment and Children's Physical Activity and Body Mass Index: Evidence from Military Personnel Installation Assignments

PubMed Central

Nicosia, Nancy; Wong, Elizabeth; Shier, Victoria

2015-01-01

Abstract Background: The majority of existing studies use observed, rather than experimental or quasi-experimental, variation in individuals' neighborhood environments to study their influence on body weight and related behaviors. Purpose: This study leverages the periodic relocation of military personnel to examine the relationship between neighborhood environment and children's physical activity (PA) and BMI in military families. Methods: This study utilizes data on 12- and 13-year-old children from the Military Teenagers Environments, Exercise, and Nutrition Study (N=903). Multivariate regression models are estimated, separately for families living on- and off-post, to examine the relationship between parents' perceptions of the neighborhood environment, measured using the Neighborhood Environment Walkability Scale–Youth Version (NEWS-Y), and children's self-reported PA and BMI. Results: Different features of the neighborhood environment were significant for off- versus on-post families. For children living off-post, a 1 standard deviation (SD) increase in the proximity-to-recreational-facilities subscale was associated with 16.5 additional minutes per week (p<0.05) of moderate PA (MPA), but street connectivity had a significant negative association with vigorous activity. For children living on-post, a 1 SD increase on the crime safety subscale was associated with 22.9 additional minutes per week (p<0.05) of MPA. None of the NEWS-Y subscales were associated with children's BMI. Conclusions: Efforts to increase children's PA in military families should take into account that different aspects of the neighborhood environment matter for children living on- versus off-post. PMID:25658385

Does substance use moderate the association of neighborhood disadvantage with perceived stress and safety in the activity spaces of urban youth?

PubMed

Mennis, Jeremy; Mason, Michael; Light, John; Rusby, Julie; Westling, Erika; Way, Thomas; Zahakaris, Nikola; Flay, Brian

2016-08-01

This study investigates the association of activity space-based exposure to neighborhood disadvantage with momentary perceived stress and safety, and the moderation of substance use on those associations, among a sample of 139 urban, primarily African American, adolescents. Geospatial technologies are integrated with Ecological Momentary Assessment (EMA) to capture exposure to neighborhood disadvantage and perceived stress and safety in the activity space. A relative neighborhood disadvantage measure for each subject is calculated by conditioning the neighborhood disadvantage observed at the EMA location on that of the home neighborhood. Generalized estimating equations (GEE) are used to model the effect of relative neighborhood disadvantage on momentary perceived stress and safety, and the extent to which substance use moderates those associations. Relative neighborhood disadvantage is significantly associated with higher perceived stress, lower perceived safety, and greater substance use involvement. The association of relative neighborhood disadvantage with stress is significantly stronger among those with greater substance use involvement. This research highlights the value of integrating geospatial technologies with EMA and developing personalized measures of environmental exposure for investigating neighborhood effects on substance use, and suggests substance use intervention strategies aimed at neighborhood conditions. Future research should seek to disentangle the causal pathways of influence and selection that relate neighborhood environment, stress, and substance use, while also accounting for the role of gender and family and peer social contexts. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

A 3D interactive multi-object segmentation tool using local robust statistics driven active contours.

PubMed

Gao, Yi; Kikinis, Ron; Bouix, Sylvain; Shenton, Martha; Tannenbaum, Allen

2012-08-01

Extracting anatomical and functional significant structures renders one of the important tasks for both the theoretical study of the medical image analysis, and the clinical and practical community. In the past, much work has been dedicated only to the algorithmic development. Nevertheless, for clinical end users, a well designed algorithm with an interactive software is necessary for an algorithm to be utilized in their daily work. Furthermore, the software would better be open sourced in order to be used and validated by not only the authors but also the entire community. Therefore, the contribution of the present work is twofolds: first, we propose a new robust statistics based conformal metric and the conformal area driven multiple active contour framework, to simultaneously extract multiple targets from MR and CT medical imagery in 3D. Second, an open source graphically interactive 3D segmentation tool based on the aforementioned contour evolution is implemented and is publicly available for end users on multiple platforms. In using this software for the segmentation task, the process is initiated by the user drawn strokes (seeds) in the target region in the image. Then, the local robust statistics are used to describe the object features, and such features are learned adaptively from the seeds under a non-parametric estimation scheme. Subsequently, several active contours evolve simultaneously with their interactions being motivated by the principles of action and reaction-this not only guarantees mutual exclusiveness among the contours, but also no longer relies upon the assumption that the multiple objects fill the entire image domain, which was tacitly or explicitly assumed in many previous works. In doing so, the contours interact and converge to equilibrium at the desired positions of the desired multiple objects. Furthermore, with the aim of not only validating the algorithm and the software, but also demonstrating how the tool is to be used, we provide

A 3D Interactive Multi-object Segmentation Tool using Local Robust Statistics Driven Active Contours

PubMed Central

Gao, Yi; Kikinis, Ron; Bouix, Sylvain; Shenton, Martha; Tannenbaum, Allen

2012-01-01

Extracting anatomical and functional significant structures renders one of the important tasks for both the theoretical study of the medical image analysis, and the clinical and practical community. In the past, much work has been dedicated only to the algorithmic development. Nevertheless, for clinical end users, a well designed algorithm with an interactive software is necessary for an algorithm to be utilized in their daily work. Furthermore, the software would better be open sourced in order to be used and validated by not only the authors but also the entire community. Therefore, the contribution of the present work is twofolds: First, we propose a new robust statistics based conformal metric and the conformal area driven multiple active contour framework, to simultaneously extract multiple targets from MR and CT medical imagery in 3D. Second, an open source graphically interactive 3D segmentation tool based on the aforementioned contour evolution is implemented and is publicly available for end users on multiple platforms. In using this software for the segmentation task, the process is initiated by the user drawn strokes (seeds) in the target region in the image. Then, the local robust statistics are used to describe the object features, and such features are learned adaptively from the seeds under a non-parametric estimation scheme. Subsequently, several active contours evolve simultaneously with their interactions being motivated by the principles of action and reaction — This not only guarantees mutual exclusiveness among the contours, but also no longer relies upon the assumption that the multiple objects fill the entire image domain, which was tacitly or explicitly assumed in many previous works. In doing so, the contours interact and converge to equilibrium at the desired positions of the desired multiple objects. Furthermore, with the aim of not only validating the algorithm and the software, but also demonstrating how the tool is to be used, we

Outdoor play among children in relation to neighborhood characteristics: a cross-sectional neighborhood observation study.

PubMed

Aarts, Marie-Jeanne; de Vries, Sanne I; van Oers, Hans Am; Schuit, Albertine J

2012-08-17

Although environmental characteristics as perceived by parents are known to be related to children's outdoor play behavior, less is known about the relation between independently measured neighborhood characteristics and outdoor play among children. The purpose of this study was to identify quantitative as well as qualitative neighborhood characteristics related to outdoor play by means of neighborhood observations. Questionnaires including questions on outdoor play behavior of the child were distributed among 3,651 parents of primary school children (aged 4-12 years). Furthermore, neighborhood observations were conducted in 33 Dutch neighborhoods to map neighborhood characteristics such as buildings, formal outdoor play facilities, public space, street pattern, traffic safety, social neighborhood characteristics, and general impression. Data of the questionnaires and the neighborhood observations were coupled via postal code of the respondents. Multilevel GEE analyses were performed to quantify the correlation between outdoor play and independently measured neighborhood characteristics. Parental education was negatively associated with outdoor play among children. Neither the presence nor the overall quality of formal outdoor play facilities were (positively) related to outdoor play among children in this study. Rather, informal play areas such as the presence of sidewalks were related to children's outdoor play. Also, traffic safety was an important characteristic associated with outdoor play. This study showed that, apart from individual factors such as parental education level, certain modifiable characteristics in the neighborhood environment (as measured by neighborhood observations) were associated with outdoor play among boys and girls of different age groups in The Netherlands. Local policy makers from different sectors can use these research findings in creating more activity-friendly neighborhoods for children.

Outdoor play among children in relation to neighborhood characteristics: a cross-sectional neighborhood observation study

PubMed Central

2012-01-01

Background Although environmental characteristics as perceived by parents are known to be related to children’s outdoor play behavior, less is known about the relation between independently measured neighborhood characteristics and outdoor play among children. The purpose of this study was to identify quantitative as well as qualitative neighborhood characteristics related to outdoor play by means of neighborhood observations. Methods Questionnaires including questions on outdoor play behavior of the child were distributed among 3,651 parents of primary school children (aged 4–12 years). Furthermore, neighborhood observations were conducted in 33 Dutch neighborhoods to map neighborhood characteristics such as buildings, formal outdoor play facilities, public space, street pattern, traffic safety, social neighborhood characteristics, and general impression. Data of the questionnaires and the neighborhood observations were coupled via postal code of the respondents. Multilevel GEE analyses were performed to quantify the correlation between outdoor play and independently measured neighborhood characteristics. Results Parental education was negatively associated with outdoor play among children. Neither the presence nor the overall quality of formal outdoor play facilities were (positively) related to outdoor play among children in this study. Rather, informal play areas such as the presence of sidewalks were related to children’s outdoor play. Also, traffic safety was an important characteristic associated with outdoor play. Conclusions This study showed that, apart from individual factors such as parental education level, certain modifiable characteristics in the neighborhood environment (as measured by neighborhood observations) were associated with outdoor play among boys and girls of different age groups in The Netherlands. Local policy makers from different sectors can use these research findings in creating more activity-friendly neighborhoods for

Modeling open-set spoken word recognition in postlingually deafened adults after cochlear implantation: some preliminary results with the neighborhood activation model.

PubMed

Meyer, Ted A; Frisch, Stefan A; Pisoni, David B; Miyamoto, Richard T; Svirsky, Mario A

2003-07-01

Do cochlear implants provide enough information to allow adult cochlear implant users to understand words in ways that are similar to listeners with acoustic hearing? Can we use a computational model to gain insight into the underlying mechanisms used by cochlear implant users to recognize spoken words? The Neighborhood Activation Model has been shown to be a reasonable model of word recognition for listeners with normal hearing. The Neighborhood Activation Model assumes that words are recognized in relation to other similar-sounding words in a listener's lexicon. The probability of correctly identifying a word is based on the phoneme perception probabilities from a listener's closed-set consonant and vowel confusion matrices modified by the relative frequency of occurrence of the target word compared with similar-sounding words (neighbors). Common words with few similar-sounding neighbors are more likely to be selected as responses than less common words with many similar-sounding neighbors. Recent studies have shown that several of the assumptions of the Neighborhood Activation Model also hold true for cochlear implant users. Closed-set consonant and vowel confusion matrices were obtained from 26 postlingually deafened adults who use cochlear implants. Confusion matrices were used to represent input errors to the Neighborhood Activation Model. Responses to the different stimuli were then generated by the Neighborhood Activation Model after incorporating the frequency of occurrence counts of the stimuli and their neighbors. Model outputs were compared with obtained performance measures on the Consonant-Vowel Nucleus-Consonant word test. Information transmission analysis was used to assess whether the Neighborhood Activation Model was able to successfully generate and predict word and individual phoneme recognition by cochlear implant users. The Neighborhood Activation Model predicted Consonant-Vowel Nucleus-Consonant test words at levels similar to those correctly

Modeling Open-Set Spoken Word Recognition in Postlingually Deafened Adults after Cochlear Implantation: Some Preliminary Results with the Neighborhood Activation Model

PubMed Central

Meyer, Ted A.; Frisch, Stefan A.; Pisoni, David B.; Miyamoto, Richard T.; Svirsky, Mario A.

2012-01-01

Hypotheses Do cochlear implants provide enough information to allow adult cochlear implant users to understand words in ways that are similar to listeners with acoustic hearing? Can we use a computational model to gain insight into the underlying mechanisms used by cochlear implant users to recognize spoken words? Background The Neighborhood Activation Model has been shown to be a reasonable model of word recognition for listeners with normal hearing. The Neighborhood Activation Model assumes that words are recognized in relation to other similar-sounding words in a listener’s lexicon. The probability of correctly identifying a word is based on the phoneme perception probabilities from a listener’s closed-set consonant and vowel confusion matrices modified by the relative frequency of occurrence of the target word compared with similar-sounding words (neighbors). Common words with few similar-sounding neighbors are more likely to be selected as responses than less common words with many similar-sounding neighbors. Recent studies have shown that several of the assumptions of the Neighborhood Activation Model also hold true for cochlear implant users. Methods Closed-set consonant and vowel confusion matrices were obtained from 26 postlingually deafened adults who use cochlear implants. Confusion matrices were used to represent input errors to the Neighborhood Activation Model. Responses to the different stimuli were then generated by the Neighborhood Activation Model after incorporating the frequency of occurrence counts of the stimuli and their neighbors. Model outputs were compared with obtained performance measures on the Consonant-Vowel Nucleus-Consonant word test. Information transmission analysis was used to assess whether the Neighborhood Activation Model was able to successfully generate and predict word and individual phoneme recognition by cochlear implant users. Results The Neighborhood Activation Model predicted Consonant-Vowel Nucleus-Consonant test

Does social support mediate the relationship among neighborhood disadvantage, incivilities, crime and physical activity?

PubMed

Soltero, Erica G; Hernandez, Daphne C; O'Connor, Daniel P; Lee, Rebecca E

2015-03-01

Neighborhood disadvantage (ND), incivilities, and crime disproportionately impact minority women, discouraging physical activity (PA). Social support (SS) is a cultural tool promoting PA in minority women. Socially supportive environments may promote PA in disadvantaged neighborhoods, yet few studies have investigated the mediating role of social support among minority women. This study examined SS as a mediator among ND, incivilities, crime, and PA. The Health Is Power study aimed to increase PA in African American and Hispanic Latina women (N=410) in Houston and Austin, TX. ND and crime data were taken from the National Neighborhood Crime Study. Incivilities were measured using the Pedestrian Environment Data Scan (PEDS). SS was measured using the Family and Friend Support for Exercise Habits scale and physical activity was measured using the International Physical Activity Questionnaire. Linear regression analysis was used to examine SS as a mediator following the Baron and Kenny method. ND was negatively associated with PA and SS. SS was not a mediator as it was not significantly associated with ND, crime, and incivilities (F(3,264)=2.02, p>.05) or PA (F(1,266)=3.8 p=.052). ND significantly discourages PA and limits SS. Future research should focus on developing strategies to overcoming these negative environmental factors. Published by Elsevier Inc.

A visual model for object detection based on active contours and level-set method.

PubMed

Satoh, Shunji

2006-09-01

A visual model for object detection is proposed. In order to make the detection ability comparable with existing technical methods for object detection, an evolution equation of neurons in the model is derived from the computational principle of active contours. The hierarchical structure of the model emerges naturally from the evolution equation. One drawback involved with initial values of active contours is alleviated by introducing and formulating convexity, which is a visual property. Numerical experiments show that the proposed model detects objects with complex topologies and that it is tolerant of noise. A visual attention model is introduced into the proposed model. Other simulations show that the visual properties of the model are consistent with the results of psychological experiments that disclose the relation between figure-ground reversal and visual attention. We also demonstrate that the model tends to perceive smaller regions as figures, which is a characteristic observed in human visual perception.

Fast Virtual Stenting with Active Contour Models in Intracranical Aneurysm

PubMed Central

Zhong, Jingru; Long, Yunling; Yan, Huagang; Meng, Qianqian; Zhao, Jing; Zhang, Ying; Yang, Xinjian; Li, Haiyun

2016-01-01

Intracranial stents are becoming increasingly a useful option in the treatment of intracranial aneurysms (IAs). Image simulation of the releasing stent configuration together with computational fluid dynamics (CFD) simulation prior to intervention will help surgeons optimize intervention scheme. This paper proposed a fast virtual stenting of IAs based on active contour model (ACM) which was able to virtually release stents within any patient-specific shaped vessel and aneurysm models built on real medical image data. In this method, an initial stent mesh was generated along the centerline of the parent artery without the need for registration between the stent contour and the vessel. Additionally, the diameter of the initial stent volumetric mesh was set to the maximum inscribed sphere diameter of the parent artery to improve the stenting accuracy and save computational cost. At last, a novel criterion for terminating virtual stent expanding that was based on the collision detection of the axis aligned bounding boxes was applied, making the stent expansion free of edge effect. The experiment results of the virtual stenting and the corresponding CFD simulations exhibited the efficacy and accuracy of the ACM based method, which are valuable to intervention scheme selection and therapy plan confirmation. PMID:26876026

Changes in the perceived neighborhood environment in relation to changes in physical activity: A longitudinal study from childhood into adolescence.

PubMed

D'Haese, Sara; De Meester, Femke; Cardon, Greet; De Bourdeaudhuij, Ilse; Deforche, Benedicte; Van Dyck, Delfien

2015-05-01

The aim was to investigate how physical activity and the perceived neighborhood environment in children change when they enter adolescence. Also the relation between changes in the perceived environment and changes in children's physical activity was investigated. In total, 321 children and one of their parents filled out a physical activity questionnaire and the NEWS-Y at two time points (last grade of elementary school and 2 years later). Children also wore an activity monitor. Changes in children's physical activity were dependent on the physical activity domain. Only less than half of children's perceived neighborhood factors changed and about half of the parental perceived neighborhood factors changed. Most of these factors changed towards higher activity friendliness. Changes in the perceived environment were only limitedly related to changes in children's physical activity. Copyright © 2015 Elsevier Ltd. All rights reserved.

The moderating effect of psychosocial factors in the relation between neighborhood walkability and children's physical activity.

PubMed

D'Haese, Sara; Gheysen, Freja; De Bourdeaudhuij, Ilse; Deforche, Benedicte; Van Dyck, Delfien; Cardon, Greet

2016-12-09

The study aimed to investigate if psychosocial factors moderate the association between objective walkability and different domains of children's physical activity (PA). A second aim of the study was to investigate the direct associations between psychosocial factors and children's PA. Based on previous literature, it was hypothesized that walkability would be more strongly related to PA among children with negative psychosocial profiles. Data were collected between December 2011 and May 2013 as part of the Belgian Environmental Physical Activity Study in children (BEPAS-child). In total, data from 494 children and one of their parents were included in the study. Children wore an accelerometer for 7 consecutive days and together with one of their parents, they completed the Flemish Physical Activity Questionnaire. Parents filled out a questionnaire concerning their child's psychosocial factors toward PA (i.e. parental attitude toward their child's PA, parental social norm toward their child's PA, parental support, friend support, children's self-efficacy, and perceived benefits and barriers toward sports and PA). Neighborhood walkability was calculated using geographical information systems (GIS). Multilevel cross-classified analyses were conducted. Of the 42 investigated interactions between neighborhood walkability and psychosocial factors in relation to PA among children, only 7 significant interactions were found of which 3 were only significant among children from low-income neighborhoods. Parental support and self-efficacy were positive correlates of children's PA in high- and low-income neighborhoods independent of the level of walkability, but effect sizes were small. The hypothesis that walkability would be more strongly related to PA among children with negative psychosocial profiles could not be confirmed and in general, psychosocial factors and objective walkability did not interact in relation to children's PA. Focusing on parental support and self

Ingenious Snake: An Adaptive Multi-Class Contours Extraction

NASA Astrophysics Data System (ADS)

Li, Baolin; Zhou, Shoujun

2018-04-01

Active contour model (ACM) plays an important role in computer vision and medical image application. The traditional ACMs were used to extract single-class of object contours. While, simultaneous extraction of multi-class of interesting contours (i.e., various contours with closed- or open-ended) have not been solved so far. Therefore, a novel ACM model named “Ingenious Snake” is proposed to adaptively extract these interesting contours. In the first place, the ridge-points are extracted based on the local phase measurement of gradient vector flow field; the consequential ridgelines initialization are automated with high speed. Secondly, the contours’ deformation and evolvement are implemented with the ingenious snake. In the experiments, the result from initialization, deformation and evolvement are compared with the existing methods. The quantitative evaluation of the structure extraction is satisfying with respect of effectiveness and accuracy.

Neighborhood factors associated with physical activity and adequacy of weight gain during pregnancy

EPA Science Inventory

Healthy diet, physical activity, smoking, and adequate weight gain are all associated with maternal health and fetal growth during pregnancy. Neighborhood characteristics have been associated with poor maternal and child health outcomes, yet conceptualization of potential mechani...

Neighborhood poverty and early transition to sexual activity in young adolescents: a developmental ecological approach.

PubMed

Dupéré, Véronique; Lacourse, Eric; Willms, J Douglas; Leventhal, Tama; Tremblay, Richard E

2008-01-01

This study examined how the link between neighborhood poverty and the timing of sexual initiation varies as a function of age, gender, and background characteristics. A sample of N = 2,596 predominately White Canadian adolescents from the National Longitudinal Survey of Children and Youth was used. Sexual initiations occurring between 12 and 15 years old were considered. Results showed that younger adolescent females who lived in poor neighborhoods and who had a history of conduct problems were more likely to report early sexual activity. Peer characteristics partly accounted for this susceptibility. Among adolescent males, no direct neighborhood effects were found, but those who had combined risks at multiple levels appeared more vulnerable. The theoretical and practical implications of these findings are discussed.

Perceived neighborhood environment and physical activity among high school students from Curitiba, Brazil.

PubMed

Lopes, Adalberto Aparecido dos Santos; Lanzoni, Alessandra Nunes; Hino, Adriano Akira Ferreira; Rodriguez-Añez, Ciro Romélio; Reis, Rodrigo Siqueira

2014-12-01

To analyze the association between perceived neighborhood environment and physical activity (PA) in high school students from Curitiba (PR), Brazil. A sample of 1,611 high school students from public schools was surveyed. The PA was assessed through questions, engaged for at least 20 minutes or 60 minutes. Perceptions on neighborhood environment were assessed through ten questions about neighborhood characteristics. Gender, age and number of cars in the household were self-reported and used as confounding variables. Absolute and relative frequencies were used in the sample, and associations were tested through adjusted logistic regressions for the confounding variables and stratified by gender (p < 0.05). The adjusted analyses showed that the variables "interesting things" among girls (OR = 1.77; 95%CI 1.05 - 2.96) and "there are places I like" (OR = 2.18; 95%CI 1.33 - 3.58) and "I see people my age", among boys, were associated with PA of at least 20 minutes/day once a week. Additionally, among boys, "I see people my age" was associated with 60-minute (OR = 1.68; 95%CI 1.15 - 2.45). Perceiving the neighborhood environment as "very good" was associated with higher chances of taking up PA among girls (OR = 1.92; 95%CI 1.15 - 3.22) and boys (OR = 3.13; 95%CI 1.97 - 4.97). A positive perception of the environment was associated to PA practice among boys and girls in this sample. The results suggest that some environmental characteristics which make neighborhoods more attractive could be related to PA among adolescents.

Using Google Street View to audit neighborhood environments.

PubMed

Rundle, Andrew G; Bader, Michael D M; Richards, Catherine A; Neckerman, Kathryn M; Teitler, Julien O

2011-01-01

Research indicates that neighborhood environment characteristics such as physical disorder influence health and health behavior. In-person audit of neighborhood environments is costly and time-consuming. Google Street View may allow auditing of neighborhood environments more easily and at lower cost, but little is known about the feasibility of such data collection. To assess the feasibility of using Google Street View to audit neighborhood environments. This study compared neighborhood measurements coded in 2008 using Street View with neighborhood audit data collected in 2007. The sample included 37 block faces in high-walkability neighborhoods in New York City. Field audit and Street View data were collected for 143 items associated with seven neighborhood environment constructions: aesthetics, physical disorder, pedestrian safety, motorized traffic and parking, infrastructure for active travel, sidewalk amenities, and social and commercial activity. To measure concordance between field audit and Street View data, percentage agreement was used for categoric measures and Spearman rank-order correlations were used for continuous measures. The analyses, conducted in 2009, found high levels of concordance (≥80% agreement or ≥0.60 Spearman rank-order correlation) for 54.3% of the items. Measures of pedestrian safety, motorized traffic and parking, and infrastructure for active travel had relatively high levels of concordance, whereas measures of physical disorder had low levels. Features that are small or that typically exhibit temporal variability had lower levels of concordance. This exploratory study indicates that Google Street View can be used to audit neighborhood environments. Copyright © 2011 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

Distributed Contour Trees

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

Morozov, Dmitriy; Weber, Gunther H.

2014-03-31

Topological techniques provide robust tools for data analysis. They are used, for example, for feature extraction, for data de-noising, and for comparison of data sets. This chapter concerns contour trees, a topological descriptor that records the connectivity of the isosurfaces of scalar functions. These trees are fundamental to analysis and visualization of physical phenomena modeled by real-valued measurements. We study the parallel analysis of contour trees. After describing a particular representation of a contour tree, called local{global representation, we illustrate how di erent problems that rely on contour trees can be solved in parallel with minimal communication.

Neighborhood built environment and socioeconomic status in relation to physical activity, sedentary behavior, and weight status of adolescents.

PubMed

Sallis, James F; Conway, Terry L; Cain, Kelli L; Carlson, Jordan A; Frank, Lawrence D; Kerr, Jacqueline; Glanz, Karen; Chapman, James E; Saelens, Brian E

2018-05-01

The study examined the association of neighborhood walkability to multiple activity-related outcomes and BMI among adolescents and evaluated socioeconomic status as an effect modifier. Cross-sectional study, with adolescents recruited from neighborhoods that met criteria for a 2 × 2 matrix defined by high/low GIS-defined walkability and high/low median income. Adolescents aged 12-16 years (n = 928) were recruited from selected neighborhoods in Maryland and King County, Washington regions in 2009-2011. There were 50.4% girls, and 66.3% were non-Hispanic white, with no medical restrictions on physical activity (PA) or diets. Total PA and sedentary time was assessed by 7 days of accelerometer monitoring. Adolescents self-reported active transport, time spent on 6 sedentary behaviors, and height and weight, used to compute BMI percentiles. Mixed model linear and logistic regressions examined outcomes for association with walkability and income, adjusting for demographic covariates and clustering within block groups. Walkability was positively and significantly related to objectively-measured PA (p < .001) and more frequent walking for transportation (p < .001). Total self-reported sedentary time (p = .048) and TV time (p < .007) were negatively related to walkability. Time in vehicles was negatively related to walkability only among higher-income adolescents. Neighborhood walkability was strongly and consistently associated with adolescents' objectively-assessed total physical activity and reported active transportation. A novel finding was that adolescents living in walkable neighborhoods reported less television time and less time in vehicles. Most results were similar across income categories. Results strengthen the rationale for recommendations to improve walkability. Copyright © 2018 Elsevier Inc. All rights reserved.

Physical activity as a mediator of the associations between neighborhood walkability and adiposity in Belgian adults.

PubMed

Van Dyck, Delfien; Cerin, Ester; Cardon, Greet; Deforche, Benedicte; Sallis, James F; Owen, Neville; de Bourdeaudhuij, Ilse

2010-09-01

This study examined whether physical activity (PA) and sedentary behavior mediated the relationship of neighborhood walkability with two measures of adiposity: body mass index (BMI) and waist-to-height ratio (WHTR). Twenty-four neighborhoods in Ghent, Belgium were selected, stratified by objectively assessed walkability and by socio-economic status. Participants (1200 adults aged 20-65 years) completed the International Physical Activity Questionnaire and wore an accelerometer for 7 days. Weight and height were self-reported and waist circumference was objectively measured. Accelerometer-assessed moderate-to-vigorous PA and self-reported cycling for transport mediated the associations of walkability with BMI and WHTR. Moreover, walking for transport and recreational walking significantly mediated the relationship between walkability and BMI. Sedentary behavior did not mediate associations of walkability with BMI or WHTR. These findings suggest that PA, but not sedentary behavior, is a mechanism by which walkability may affect adults' adiposity. Planning for neighborhoods to be high in walkability could have favorable effects on physical activity and weight status. Copyright 2010 Elsevier Ltd. All rights reserved.

Does community type moderate the relationship between parent perceptions of the neighborhood and physical activity in children?

PubMed

Durand, Casey P; Dunton, Genevieve F; Spruijt-Metz, Donna; Pentz, Mary Ann

2012-01-01

To examine whether residing in a community designed to promote physical activity moderates the relationship between parent perceptions of the neighborhood and general physical activity or active commuting to school in their children. Cross-sectional. San Bernardino County, California. Three hundred sixty-five families (one parent and one child in grades four through eight). Eighty-five reside in a smart growth community designed to be more conducive to physical activity. Parent perceptions assessed using the Neighborhood Environment Walkability Scale (NEWS). General child physical activity was measured using accelerometers, and active commuting was self-reported by children. Two sets of regressions were performed: one for general physical activity, and one for active commuting. Separate models were run in the two sets for each of the 14 NEWS factors, while controlling for demographics. For general physical activity, walking infrastructure, lack of cul-de-sacs, and social interaction had significant main effect associations (p ≤ .05). No factors were moderated by community. The relationships between active commuting to school and perceived crime, traffic hazards, hilliness, physical barriers, cul-de-sac connectivity, aesthetics, and walking infrastructure were significant for those in the smart growth community only (p ≤ .05). Living in an activity-friendly environment is associated with positive relationships between parent perceptions and active commuting behaviors in children. Future interventions should account for both the perceived neighborhood environment and available physical activity infrastructure.

Prediction and characterization of enzymatic activities guided by sequence similarity and genome neighborhood networks

DOE PAGES

Zhao, Suwen; Sakai, Ayano; Zhang, Xinshuai; ...

2014-06-30

Metabolic pathways in eubacteria and archaea often are encoded by operons and/or gene clusters (genome neighborhoods) that provide important clues for assignment of both enzyme functions and metabolic pathways. We describe a bioinformatic approach (genome neighborhood network; GNN) that enables large scale prediction of the in vitro enzymatic activities and in vivo physiological functions (metabolic pathways) of uncharacterized enzymes in protein families. We demonstrate the utility of the GNN approach by predicting in vitro activities and in vivo functions in the proline racemase superfamily (PRS; InterPro IPR008794). The predictions were verified by measuring in vitro activities for 51 proteins inmore » 12 families in the PRS that represent ~85% of the sequences; in vitro activities of pathway enzymes, carbon/nitrogen source phenotypes, and/or transcriptomic studies confirmed the predicted pathways. The synergistic use of sequence similarity networks3 and GNNs will facilitate the discovery of the components of novel, uncharacterized metabolic pathways in sequenced genomes.« less

WE-E-213CD-08: A Novel Level Set Active Contour Algorithm Using the Jensen-Renyi Divergence for Tumor Segmentation in PET.

PubMed

Markel, D; Naqa, I El

2012-06-01

Positron emission tomography (PET) presents a valuable resource for delineating the biological tumor volume (BTV) for image-guided radiotherapy. However, accurate and consistent image segmentation is a significant challenge within the context of PET, owing to its low spatial resolution and high levels of noise. Active contour methods based on the level set methods can be sensitive to noise and susceptible to failing in low contrast regions. Therefore, this work evaluates a novel active contour algorithm applied to the task of PET tumor segmentation. A novel active contour segmentation algorithm based on maximizing the Jensen-Renyi Divergence between regions of interest was applied to the task of segmenting lesions in 7 patients with T3-T4 pharyngolaryngeal squamous cell carcinoma. The algorithm was implemented on an NVidia GEFORCE GTV 560M GPU. The cases were taken from the Louvain database, which includes contours of the macroscopically defined BTV drawn using histology of resected tissue. The images were pre-processed using denoising/deconvolution. The segmented volumes agreed well with the macroscopic contours, with an average concordance index and classification error of 0.6 ± 0.09 and 55 ± 16.5%, respectively. The algorithm in its present implementation requires approximately 0.5-1.3 sec per iteration and can reach convergence within 10-30 iterations. The Jensen-Renyi active contour method was shown to come close to and in terms of concordance, outperforms a variety of PET segmentation methods that have been previously evaluated using the same data. Further evaluation on a larger dataset along with performance optimization is necessary before clinical deployment. © 2012 American Association of Physicists in Medicine.

An Alternative to Residential Neighborhoods: An Exploratory Study of How Activity Spaces and Perception of Neighborhood Social Processes Relate to Maladaptive Parenting

ERIC Educational Resources Information Center

Freisthler, Bridget; Thomas, Crystal A.; Curry, Susanna R.; Wolf, Jennifer Price

2016-01-01

Background: The environments where parents spend time, such as at work, at their child's school, or with friends and family, may exert a greater influence on their parenting behaviors than the residential neighborhoods where they live. These environments, termed activity spaces, provide individualized information about the where parents go,…

Effects of Neighborhood Walkability on Physical Activity and Sedentary Behavior Long-Term Post-Bariatric Surgery.

PubMed

Reid, Ryan E R; Carver, Tamara E; Reid, Tyler G R; Picard-Turcot, Marie-Aude; Andersen, Kathleen M; Christou, Nicolas V; Andersen, Ross E

2017-06-01

ᅟ: Chronic inactivity and weight regain are serious health concerns following bariatric surgery. Neighborhood walkability is associated with higher physical activity and lower obesity rates in normal weight populations. Explore the influence of neighborhood walkability on physical activity and sedentarism among long-term post-bariatric surgery patients. Fifty-eight adults aged 50.5 ± 9.1 years, with a BMI of 34.6 ± 9.7 kg/m 2 having undergone surgery 9.8 ± 3.15 years earlier participated in this study. Participants were asked to wear an ActivPAL™ tri-axial accelerometer attached to their mid-thigh for 7-consecutive days, 24 hours/day. The sample was separated into those that live in Car-Dependent (n = 23), Somewhat Walkable (n = 14), Very Walkable (n = 16), and Walker's Paradise (n = 5) neighborhoods as defined using Walk Score®. ANCOVA was performed comparing Walk Score® categories on steps and sedentary time controlling for age and sex. Neighborhood walkability did not influence either daily steps (F (3, 54) = 0.921, p = 0.437) or sedentary time (F (3, 54) = 0.465, p = 0.708), Car-Dependent (6359 ± 2712 steps, 9.54 ± 2.46 hrs), Somewhat Walkable (6563 ± 2989 steps, 9.07 ± 2.70 hrs), Very Walkable (5261 ± 2255 steps, 9.97 ± 2.06 hrs), and Walker's Paradise (6901 ± 1877 steps, 10.14 ± 0.815 hrs). Walkability does not appear to affect sedentary time or physical activity long-term post-surgery. As the built-environment does not seem to influence activity, sedentarism, or obesity as it does with a normal weight population, work needs to be done to tailor physical activity programming after bariatric surgery.

Harnessing Technology and Citizen Science to Support Neighborhoods that Promote Active Living in Mexico.

PubMed

Rosas, Lisa G; Salvo, Deborah; Winter, Sandra J; Cortes, David; Rivera, Juan; Rodriguez, Nicole M; King, Abby C

2016-12-01

Middle- and low-income countries bear 80 % of the global chronic disease burden. Population-level, multi-sectoral approaches to promoting healthful lifestyles that take into local physical, socioeconomic, and sociocultural characteristics of both the environment and the population are needed. The "Nuestra Voz (Our Voice)" is one such approach that involves neighborhood residents acting as "citizen scientists" to systematically gather information on the barriers and facilitators of physical activity in their neighborhoods and then use their data to collectively advocate for local environmental- and policy-level changes to support active living. We pilot tested this approach in Cuernavaca, Mexico with adults and adolescents. This community-engaged and participatory approach is driven by residents, who utilize a GPS-enabled electronic tablet-based application with simple audio-based instructions to take photographs and record audio narratives of facets of their neighborhood that promote or hinder active living. After collecting these data, the citizen scientists come together in a community meeting and use their data to prioritize realistic, multi-level changes for promoting active living in their neighborhoods. A survey assessed participants' acceptability of the approach. Participating citizen scientists included 32 adults and 9 adolescents. The citizen scientists rated the acceptability of five of the nine acceptability survey items with an average of 4.0 or higher out of 5.0, indicating they thought it was "fun," were comfortable carrying the tablet, were likely to use it again, and would recommend it to friends and family. Items with average scores of less than 4 were all related to safety concerns. The most common barriers reported by citizen scientists using the tablet were poor sidewalk quality, presence of trash, negative characteristics of the streets, unpleasant aesthetics (e.g., graffiti), and presence of parks and recreational facilities. The Our Voice

Neighborhood Poverty. Policy Implications in Studying Neighborhoods. Volume II.

ERIC Educational Resources Information Center

Brooks-Gunn, Jeanne, Ed.; Duncan, Greg J., Ed.; Aber, J. Lawrence, Ed.

Volume 2 of the "Neighborhood Poverty" series incorporates empirical data on neighborhood poverty into discussions of policy and program development. The chapters are: (1) "Ecological Perspectives on the Neighborhood Context of Urban Poverty: Past and Present" (Robert J. Sampson and Jeffrey D. Morenoff); (2) "The Influence of Neighborhoods on…

Adaptation, test-retest reliability, and construct validity of the Physical Activity Neighborhood Environment Scale in Nigeria (PANES-N).

PubMed

Oyeyemi, Adewale L; Sallis, James F; Oyeyemi, Adetoyeje Y; Amin, Mariam M; De Bourdeaudhuij, Ilse; Deforche, Benedicte

2013-11-01

This study adapted the Physical Activity Neighborhood Environment Scale (PANES) to the Nigerian context and assessed the test-retest reliability and construct validity of the Nigerian version (PANESN). A multidisciplinary panel of experts adapted the original PANES to reflect the built and social environment of Nigeria. The adapted PANES was subjected to cognitive testing and test retest reliability in a diverse sample of Nigerian adults (N = 132) from different neighborhood types. Intraclass Correlation Coefficients (ICC) was used to assess test-retest reliability, and construct validity was investigated with Analysis of Covariance for differences in environmental attributes between neighborhoods. Four of the 17 items on the original PANES were significantly modified, 3 were removed and 2 new items were incorporated into the final version of adapted PANES-N. Test-retest reliability was substantial to almost perfect (ICC = 0.62-1.00) for all items on the PANES-N, and residents of neighborhoods in the inner city reported higher residential density, land use mix and safety, but lower pedestrian facilities and aesthetics than did residents of government reserved area/new layout neighborhoods. The PANES-N appears promising for assessing environmental perceptions related to physical activity in Nigeria, but further testing is required to assess its applicability across Africa.

Gallbladder Boundary Segmentation from Ultrasound Images Using Active Contour Model

NASA Astrophysics Data System (ADS)

Ciecholewski, Marcin

Extracting the shape of the gallbladder from an ultrasonography (US) image allows superfluous information which is immaterial in the diagnostic process to be eliminated. In this project an active contour model was used to extract the shape of the gallbladder, both for cases free of lesions, and for those showing specific disease units, namely: lithiasis, polyps and changes in the shape of the organ, such as folds or turns of the gallbladder. The approximate shape of the gallbladder was found by applying the motion equation model. The tests conducted have shown that for the 220 US images of the gallbladder, the area error rate (AER) amounted to 18.15%.

The First National Study of Neighborhood Parks

PubMed Central

Cohen, Deborah A.; Han, Bing; Nagel, Catherine; Harnik, Peter; McKenzie, Thomas L.; Evenson, Kelly R.; Marsh, Terry; Williamson, Stephanie; Vaughan, Christine; Katta, Sweatha

2016-01-01

Introduction An extensive infrastructure of neighborhood parks supports leisure time physical activity in most U.S. cities; yet, most Americans do not meet national guidelines for physical activity. Neighborhood parks have never been assessed nationally to identify their role in physical activity. Methods Using a stratified multistage sampling strategy, a representative sample of 174 neighborhood parks in 25 major cities (population >100,000) across the U.S. was selected. Park use, park-based physical activity, and park conditions were observed during a typical week using systematic direct observation during spring/summer of 2014. Park administrators were interviewed to assess policies and practices. Data were analyzed in 2014–2015 using repeated-measure negative binomial regressions to estimate weekly park use and park-based physical activity. Results Nationwide, the average neighborhood park of 8.8 acres averaged 23 users/hour or an estimated 1,533 person hours of weekly use. Walking loops and gymnasia each generated 221 hours/week of moderate to vigorous physical activity. Seniors represented 4% of park users, but 20% of the general population. Parks were used less in low-income than in high-income neighborhoods, largely explained by fewer supervised activities and marketing/outreach efforts. Programming and marketing were associated with 37% and 63% more hours of moderate to vigorous physical activity/week in parks, respectively. Conclusions The findings establish national benchmarks for park use, which can guide future park investments and management practices to improve population health. Offering more programming, using marketing tools like banners and posters, and installing facilities like walking loops may help currently underutilized parks increase population physical activity. PMID:27209496

Leveraging geotagged Twitter data to examine neighborhood happiness, diet, and physical activity

PubMed Central

Nguyen, Quynh C; Kath, Suraj; Meng, Hsien-Wen; Li, Dapeng; Smith, Ken Robert; VanDerslice, James A.; Wen, Ming; Li, Feifei

2016-01-01

Objectives Using publicly available, geotagged Twitter data, we created neighborhood indicators for happiness, food and physical activity for three large counties: Salt Lake, San Francisco and New York. Methods We utilize 2.8 million tweets collected between February-August 2015 in our analysis. Geo-coordinates of where tweets were sent allow us to spatially join them to 2010 census tract locations. We implemented quality control checks and tested associations between Twitter-derived variables and sociodemographic characteristics. Results For a random subset of tweets, manually labeled tweets and algorithm labeled tweets had excellent levels of agreement: 73% for happiness; 83% for food, and 85% for physical activity. Happy tweets, healthy food references, and physical activity references were less frequent in census tracts with greater economic disadvantage and higher proportions of racial/ethnic minorities and youths. Conclusions Social media can be leveraged to provide greater understanding of the well-being and health behaviors of communities—information that has been previously difficult and expensive to obtain consistently across geographies. More open access neighborhood data can enable better design of programs and policies addressing social determinants of health. PMID:28533568

The Effect of Light Rail Transit on Physical Activity: Design and Methods of the Travel-Related Activity in Neighborhoods Study.

PubMed

Durand, Casey P; Oluyomi, Abiodun O; Gabriel, Kelley Pettee; Salvo, Deborah; Sener, Ipek N; Hoelscher, Deanna M; Knell, Gregory; Tang, Xiaohui; Porter, Anna K; Robertson, Michael C; Kohl, Harold W

2016-01-01

Use of mass transit has been proposed as a way to incorporate regular physical activity into daily life because transit use typically requires additional travel to access and depart the stop or station. If this additional travel is active, a small but potentially important amount of physical activity can be achieved daily. Although prior research has shown that transit use is associated with physical activity, important questions remain unanswered. Utilizing a major expansion of the Houston, TX, USA light-rail system as a natural experiment, the Houston Travel-Related Activity in Neighborhoods (TRAIN) Study was developed to address these unanswered questions. The purpose of the TRAIN Study is to determine if the development of light-rail lines in Houston, TX, USA will prospectively affect both transit use and physical activity over 4 years. We also aim to understand how contextual effects (i.e., moderators or interaction effects), such as the neighborhood built environment and socioeconomic factors, affect the primary relations under study. The TRAIN Study is a longitudinal cohort design, in which participants are recruited at baseline from a 3-mile buffer around each of the three new lines and measured annually four times. Recruitment is accomplished via telephone contact, ads in newspapers and advertising circulars, and targeted community outreach. Data are collected via mail and include questionnaire-assessed factors, such as perceived neighborhood characteristics, attitudes about transportation, demographics, and reported physical activity; a travel diary; and accelerometry. Additionally, field-based neighborhood audits are conducted to capture micro-scale environmental features. To assess macro-scale environmental characteristics, we utilize GIS mapping and spatial analyses. Statistical analyses will be conducted using latent growth curve modeling and discrete choice models, with a focus on identifying moderating factors (i.e., statistical interaction

Do Natural Experiments of Changes in Neighborhood Built Environment Impact Physical Activity and Diet? A Systematic Review

PubMed Central

George, Emma S.; Feng, Xiaoqi; Merom, Dafna; Bennie, Andrew; Cook, Amelia; Dwyer, Genevieve; Pang, Bonnie; Astell-Burt, Thomas

2018-01-01

Physical activity and diet are major modifiable risk factors for chronic disease and have been shown to be associated with neighborhood built environment. Systematic review evidence from longitudinal studies on the impact of changing the built environment on physical activity and diet is currently lacking. A systematic review of natural experiments of neighborhood built environment was conducted. The aims of this systematic review were to summarize study characteristics, study quality, and impact of changes in neighborhood built environment on physical activity and diet outcomes among residents. Natural experiments of neighborhood built environment change, exploring longitudinal impacts on physical activity and/or diet in residents, were included. From five electronic databases, 2084 references were identified. A narrative synthesis was conducted, considering results in relation to study quality. Nineteen papers, reporting on 15 different exposures met inclusion criteria. Four studies included a comparison group and 11 were pre-post/longitudinal studies without a comparison group. Studies reported on the impact of redeveloping or introducing cycle and/or walking trails (n = 5), rail stops/lines (n = 4), supermarkets and farmers’ markets (n = 4) and park and green space (n = 2). Eight/15 studies reported at least one beneficial change in physical activity, diet or another associated health outcome. Due to limitations in study design and reporting, as well as the wide array of outcome measures reported, drawing conclusions to inform policy was challenging. Future research should consider a consistent approach to measure the same outcomes (e.g., using measurement methods that collect comparable physical activity and diet outcome data), to allow for pooled analyses. Additionally, including comparison groups wherever possible and ensuring high quality reporting is essential. PMID:29373567

Do Natural Experiments of Changes in Neighborhood Built Environment Impact Physical Activity and Diet? A Systematic Review.

PubMed

MacMillan, Freya; George, Emma S; Feng, Xiaoqi; Merom, Dafna; Bennie, Andrew; Cook, Amelia; Sanders, Taren; Dwyer, Genevieve; Pang, Bonnie; Guagliano, Justin M; Kolt, Gregory S; Astell-Burt, Thomas

2018-01-26

Physical activity and diet are major modifiable risk factors for chronic disease and have been shown to be associated with neighborhood built environment. Systematic review evidence from longitudinal studies on the impact of changing the built environment on physical activity and diet is currently lacking. A systematic review of natural experiments of neighborhood built environment was conducted. The aims of this systematic review were to summarize study characteristics, study quality, and impact of changes in neighborhood built environment on physical activity and diet outcomes among residents. Natural experiments of neighborhood built environment change, exploring longitudinal impacts on physical activity and/or diet in residents, were included. From five electronic databases, 2084 references were identified. A narrative synthesis was conducted, considering results in relation to study quality. Nineteen papers, reporting on 15 different exposures met inclusion criteria. Four studies included a comparison group and 11 were pre-post/longitudinal studies without a comparison group. Studies reported on the impact of redeveloping or introducing cycle and/or walking trails ( n = 5), rail stops/lines ( n = 4), supermarkets and farmers' markets ( n = 4) and park and green space ( n = 2). Eight/15 studies reported at least one beneficial change in physical activity, diet or another associated health outcome. Due to limitations in study design and reporting, as well as the wide array of outcome measures reported, drawing conclusions to inform policy was challenging. Future research should consider a consistent approach to measure the same outcomes (e.g., using measurement methods that collect comparable physical activity and diet outcome data), to allow for pooled analyses. Additionally, including comparison groups wherever possible and ensuring high quality reporting is essential.

[Impact of out-of-home activities, neighborhood and urban-related identity on well-being in old age].

PubMed

Oswald, F; Konopik, N

2015-07-01

Aging in a neighborhood environment is considered to be important for well-being particularly in very old age. The project "This is my place" - On the importance of a place in the neighborhood for healthy aging (German acronym BEWOHNT) emphasises the role of out of home activities, neighborhood experiences and urban-related identity on well-being. The aim of this paper is to test the impact of person-environment exchange processes of "agency" (e.g., out-of-home activity) and "belonging" (e.g., urban related identity, social cohesion) on well-being (valuation of life) in addition to health effects Data are based on domestic diaries, mobility diaries and a survey including 595 community-dwelling elderly people from 3 urban districts of Frankfurt (Germany) stratified by age (70-79 years vs. 80-89 years) and household situation (e.g. living alone versus living with partner). The findings indicate substantial associations for "agency" and "belonging" indicators on well-being and differentiated effects for both age groups. Multigroup analyses show that particularly in very old age, out of home activities, social cohesion and urban-related identity considerably buffer the negative impacts of health on well-being. The findings underline the need for an age-differentiated understanding of person-environment interchange processes in later life and in particular the importance of the neighborhood in very old age in this respect.

[Body-contouring surgery].

PubMed

Pitanguy, Ivo

2003-01-01

Concepts of beauty have been continuously evolving throughout the history of mankind. The voluptuous figures that were idealized by artists in the past have been substituted by slimmer forms. Medical advances in this century have permitted safe and efficient surgical correction of contour deformities. Until recently, these alterations were mostly hidden under heavy clothing or were reluctantly accepted. Current fashion trends generally promote body-revealing attire. The media frequently encourages the importance of fitness and good health linking these qualities with youthfulness and beauty. The subliminal as well as overt message is that these are necessary and desirable requirements for social acceptance and professional success. On the other hand, current sedentary lifestyle and dietary excesses, associated with factors such as genetic determination, pregnancy and the aging process, contribute to alterations of body contour that result in the loss of the individual's body image. This creates a strong psychological motivation for surgical correction. Localized fat deposits and skin flaccidity are sometimes resistant to the most sincere efforts in weight loss and sport activities. This ever-increasing request for contour surgery has been favorably met by safe and effective anesthesiology as well as efficient surgical techniques, resulting in a high degree of patient satisfaction. It is essential that today's aesthetic surgeon understand the motivations of patients who present with body contour deformities. A request for surgical treatment should be seen as a legitimate desire to achieve a physical form that approximates the individual with his or her ideal self-image. Additionally, the surgeon must always consider the possible benefit of including the participation of a multidisciplinary team approach. Depending on each case, this team should include consultants in endocrinology, dermatology, oculoplastics, pediatrics and other appropriate specialties.

Does Parents' Social Cohesion Influence Their Perception of Neighborhood Safety and Their Children's Active Commuting to and From School?

PubMed

Salahuddin, Meliha; Nehme, Eileen; Ranjit, Nalini; Kim, Young-Jae; Oluyomi, Abiodun O; Dowdy, Diane; Lee, Chanam; Ory, Marcia; Hoelscher, Deanna M

2016-12-01

The role of parents' perceptions of the neighborhood environment in determining children's active commuting to and from school (ACS) is understudied. This study examined the association between parents' perceptions of neighborhood social cohesion, perceived neighborhood safety, and their children's ACS. This cross-sectional analysis (n = 857 from 81 elementary schools in Texas) examined baseline data from the Texas Childhood Obesity Prevention Policy Evaluation project. Participants had a mean age of 9.6 (0.6) years, and 50% were girls. Mixed effects logistic regression models were used to assess gender-stratified associations between parent's perceived social cohesion and children's ACS and their perception of neighborhood safety. A positive significant association was observed between levels of perceived social cohesion and children's ACS for boys (P = 0.047); however, an inverse significant association was observed among girls (P = 0.033). Parents of boys living in neighborhoods with medium to high social cohesion were more likely to perceive their neighborhood as safe compared with parents living in neighborhoods with low social cohesion, though nonsignificant. Perceived neighborhood safety for walking and biking was associated with greater ACS among boys (P = 0.003). Our study findings indicate that both social and physical environments are important factors in determining ACS among boys.

Children's perceptions of their home and neighborhood environments, and their association with objectively measured physical activity: a qualitative and quantitative study.

PubMed

Hume, C; Salmon, J; Ball, K

2005-02-01

Environmental factors may have an important influence on children's physical activity, yet children's perspectives of their home and neighborhood environments have not been widely assessed. The aim of this study was to investigate children's perceptions of their environments, and to examine associations between these perceptions and objectively measured physical activity. The sample consisted of 147, 10-year-old Australian children, who drew maps of their home and neighborhood environments. A subsample of children photographed places and things in these environments that were important to them. The maps were analyzed for themes, and for the frequency with which particular objects and locations appeared. Physical activity was objectively measured using accelerometers. Six themes emerged from the qualitative analysis of the maps and photographs: the family home; opportunities for physical activity and sedentary pursuits; food items and locations; green space and outside areas; the school and opportunities for social interaction. Of the 11 variables established from these themes, one home and two neighborhood factors were associated with children's physical activity. These findings contribute to a broader understanding of children's perceptions of their environment, and highlight the potential importance of the home and neighborhood environments for promoting physical activity behavior.

Quasi-causal associations of physical activity and neighborhood walkability with body mass index: a twin study.

PubMed

Duncan, Glen E; Cash, Stephanie Whisnant; Horn, Erin E; Turkheimer, Eric

2015-01-01

Physical activity, neighborhood walkability, and body mass index (BMI, kg/m(2)) associations were tested using quasi-experimental twin methods. We hypothesized that physical activity and walkability were independently associated with BMI within twin pairs, controlling for genetic and environmental background shared between them. Data were from 6376 (64% female; 58% identical) same-sex pairs, University of Washington Twin Registry, 2008-2013. Neighborhood walking, moderate-to-vigorous physical activity (MVPA), and BMI were self-reported. Residential address was used to calculate walkability. Phenotypic (non-genetically informed) and biometric (genetically informed) regression was employed, controlling for age, sex, and race. Walking and MVPA were associated with BMI in phenotypic analyses; associations were attenuated but significant in biometric analyses (Ps<0.05). Walkability was not associated with BMI, however, was associated with walking (but not MVPA) in both phenotypic and biometric analyses (Ps<0.05), with no attenuation accounting for shared genetic and environmental background. The association between activity and BMI is largely due to shared genetic and environmental factors, but a significant causal relationship remains accounting for shared background. Although walkability is not associated with BMI, it is associated with neighborhood walking (but not MVPA) accounting for shared background, suggesting a causal relationship between them. Copyright © 2014 Elsevier Inc. All rights reserved.

Incorporating Neighborhood Choice in a Model of Neighborhood Effects on Income.

PubMed

van Ham, Maarten; Boschman, Sanne; Vogel, Matt

2018-05-09

Studies of neighborhood effects often attempt to identify causal effects of neighborhood characteristics on individual outcomes, such as income, education, employment, and health. However, selection looms large in this line of research, and it has been argued that estimates of neighborhood effects are biased because people nonrandomly select into neighborhoods based on their preferences, income, and the availability of alternative housing. We propose a two-step framework to disentangle selection processes in the relationship between neighborhood deprivation and earnings. We model neighborhood selection using a conditional logit model, from which we derive correction terms. Driven by the recognition that most households prefer certain types of neighborhoods rather than specific areas, we employ a principle components analysis to reduce these terms into eight correction components. We use these to adjust parameter estimates from a model of subsequent neighborhood effects on individual income for the unequal probability that a household chooses to live in a particular type of neighborhood. We apply this technique to administrative data from the Netherlands. After we adjust for the differential sorting of households into certain types of neighborhoods, the effect of neighborhood income on individual income diminishes but remains significant. These results further emphasize that researchers need to be attuned to the role of selection bias when assessing the role of neighborhood effects on individual outcomes. Perhaps more importantly, the persistent effect of neighborhood deprivation on subsequent earnings suggests that neighborhood effects reflect more than the shared characteristics of neighborhood residents: place of residence partially determines economic well-being.

Comparative study on the performance of textural image features for active contour segmentation.

PubMed

Moraru, Luminita; Moldovanu, Simona

2012-07-01

We present a computerized method for the semi-automatic detection of contours in ultrasound images. The novelty of our study is the introduction of a fast and efficient image function relating to parametric active contour models. This new function is a combination of the gray-level information and first-order statistical features, called standard deviation parameters. In a comprehensive study, the developed algorithm and the efficiency of segmentation were first tested for synthetic images. Tests were also performed on breast and liver ultrasound images. The proposed method was compared with the watershed approach to show its efficiency. The performance of the segmentation was estimated using the area error rate. Using the standard deviation textural feature and a 5×5 kernel, our curve evolution was able to produce results close to the minimal area error rate (namely 8.88% for breast images and 10.82% for liver images). The image resolution was evaluated using the contrast-to-gradient method. The experiments showed promising segmentation results.

Entropy reduction via simplified image contourization

NASA Technical Reports Server (NTRS)

Turner, Martin J.

1993-01-01

The process of contourization is presented which converts a raster image into a set of plateaux or contours. These contours can be grouped into a hierarchical structure, defining total spatial inclusion, called a contour tree. A contour coder has been developed which fully describes these contours in a compact and efficient manner and is the basis for an image compression method. Simplification of the contour tree has been undertaken by merging contour tree nodes thus lowering the contour tree's entropy. This can be exploited by the contour coder to increase the image compression ratio. By applying general and simple rules derived from physiological experiments on the human vision system, lossy image compression can be achieved which minimizes noticeable artifacts in the simplified image.

Longitudinal relationships between self-concept for physical activity and neighborhood social life as predictors of physical activity among older African American adults.

PubMed

Sweeney, Allison M; Wilson, Dawn K; Lee Van Horn, M

2017-05-22

Engaging in regular physical activity (PA) as an older adult has been associated with numerous physical and mental health benefits. The aim of this study is to directly compare how individual-level cognitive factors (self-efficacy for PA, self-determined motivation for PA, self-concept for PA) and neighborhood perceptions of the social factors (neighborhood satisfaction, neighborhood social life) impact moderate-to-vigorous physical activity (MVPA) longitudinally among older African American adults. Data were analyzed from a sub-set of older African American adults (N = 224, M age  = 63.23 years, SD = 8.74, 63.23% female, M Body Mass Index  = 32.01, SD = 7.52) enrolled in the Positive Action for Today's Health trial. MVPA was assessed using 7-day accelerometry-estimates and psychosocial data (self-efficacy for PA, self-determined motivation for PA, self-concept for PA, neighborhood satisfaction, neighborhood social life) were collected at baseline, 12-, 18-, and 24-months. Multilevel growth modeling was used to examine within- and between-person effects of individual-level cognitive and social environmental factors on MVPA. At the between-person level, self-concept (b = 0.872, SE = 0.239, p < 0.001), and neighborhood social life (b = 0.826, SE = 0.176, p < 0.001) predicted greater MVPA, whereas neighborhood satisfaction predicted lower MVPA (b = -0.422, SE = 0.172, p = 0.015). Among the between-person effects, only average social life was moderated by time (b = 0.361, SE = 0.147, p = 0.014), indicating that the impact of a relatively positive social life on MVPA increased across time. At the within-person level, positive increases in self-concept (b = 0.294, SE = 0.145, p = 0.043) and neighborhood social life (b = 0.270, SE = 0.113, p = 0.017) were associated with increased MVPA. These results suggest that people with a higher average self-concept for PA and a more positive social life engaged in greater average MVPA

Neighborhood Incivilities, Perceived Neighborhood Safety, and Walking to School Among Urban-Dwelling Children

PubMed Central

Rossen, Lauren M.; Pollack, Keshia M.; Curriero, Frank C.; Shields, Timothy M.; Smart, Mieka J.; Furr-Holden, C. Debra M.; Cooley-Strickland, Michele

2011-01-01

Background Walking to school is an important source of physical activity among children. There is a paucity of research exploring environmental determinants of walking to school among children in urban areas. Methods A cross-sectional secondary analysis of baseline data (2007) from 365 children in the “Multiple Opportunities to Reach Excellence” (MORE) Study (8 to 13 years; Mean 9.60 years, SD 1.04). Children and caregivers were asked about walking to school and perceived safety. Objective measures of the environment were obtained using a validated environmental neighborhood assessment. Results Over half (55.83%) of children reported walking to school most of the time. High levels of neighborhood incivilities were associated with lower levels of perceived safety (OR: 0.39, 95% CI: 0.21 to 0.72). Living on a block above the median in incivilities was associated with a 353% increase in odds of walking to school (OR: 3.53; 95% CI: 1.68 to 7.39). Conclusions Children residing in neighborhoods high in incivilities are more likely to walk to school, in spite of lower levels of perceived safety. As a high proportion of children residing in disadvantaged neighborhoods walk to school, efforts should be directed at minimizing exposure to neighborhood hazards by ensuring safe routes to and from school. PMID:21415453

A new fractional order derivative based active contour model for colon wall segmentation

NASA Astrophysics Data System (ADS)

Chen, Bo; Li, Lihong C.; Wang, Huafeng; Wei, Xinzhou; Huang, Shan; Chen, Wensheng; Liang, Zhengrong

2018-02-01

Segmentation of colon wall plays an important role in advancing computed tomographic colonography (CTC) toward a screening modality. Due to the low contrast of CT attenuation around colon wall, accurate segmentation of the boundary of both inner and outer wall is very challenging. In this paper, based on the geodesic active contour model, we develop a new model for colon wall segmentation. First, tagged materials in CTC images were automatically removed via a partial volume (PV) based electronic colon cleansing (ECC) strategy. We then present a new fractional order derivative based active contour model to segment the volumetric colon wall from the cleansed CTC images. In this model, the regionbased Chan-Vese model is incorporated as an energy term to the whole model so that not only edge/gradient information but also region/volume information is taken into account in the segmentation process. Furthermore, a fractional order differentiation derivative energy term is also developed in the new model to preserve the low frequency information and improve the noise immunity of the new segmentation model. The proposed colon wall segmentation approach was validated on 16 patient CTC scans. Experimental results indicate that the present scheme is very promising towards automatically segmenting colon wall, thus facilitating computer aided detection of initial colonic polyp candidates via CTC.

Racial Differences in Neighborhood Perceptions and their Influences on Physical Activity among Urban Older Women.

PubMed

Li, Wenjun; Procter-Gray, Elizabeth; Youssef, Gretchen A; Crouter, Scott E; Cheng, Jie; Brown, Kristen; Churchill, Linda; Clarke, Anthony; Ockene, Judith K; Magee, Michelle F

2017-01-01

Proper levels of physical activity (PA) are important to healthy aging. Little is known about racial differences in influences of neighborhood perceptions (NP) on PA and use of neighborhood resources among community-dwelling older women. In 2014 and 2015, 49 white and 44 black women of age 65 and older living in Washington, DC were queried about their PA, NP, use of neighborhood resources and sociodemographic characteristics. They wore an accelerometer and a Global Positioning System device concurrently for 7 consecutive days. Data were analyzed by race. Compared to Whites, Blacks had lower NP scores (71% positive vs. 77%, p = 0.01), lower mean daily step counts (mean (SD): 3256 (1918) vs. 5457 (2989), p < 0.001), and lower frequencies of all exercise activities combined (19.7 (8.7) vs. 25.2 (11.8) per week, p = 0.01). For both Whites and Blacks, better NPs were associated with more frequent PA both at ( p = 0.05) and away from home ( p = 0.01). However, better NPs were associated with higher frequencies of exercise activities, moderate-to-high intensity activities, and utilitarian walking for Whites but not Blacks ( p < 0.05 for race-perception interaction terms). In an urban setting, older Black women were more likely than older White women to have poor NPs, less PA, and weaker or no association of positive NPs with higher levels of certain PAs. Such substantial racial differences warrant further investigation and consideration in health promotion programs.

Pedestrian Validation in Infrared Images by Means of Active Contours and Neural Networks

DTIC Science & Technology

2010-01-01

Research Article Pedestrian Validation in Infrared Images byMeans of Active Contours and Neural Networks Massimo Bertozzi,1 Pietro Cerri,1 Mirko Felisa,1...Stefano Ghidoni,2 andMichael Del Rose3 1VisLab, Dipartimento di Ingegneria dell’Informazione, Università di Parma, 43124 Parma, Italy 2 IAS-Lab...Dipartimento di Ingegneria dell’Informazione, Università di Padova, 35131 Padova, Italy 3Vetronics Research Center, U. S. Army TARDEC, MI 48397, USA

Method for contour extraction for object representation

DOEpatents

Skourikhine, Alexei N.; Prasad, Lakshman

2005-08-30

Contours are extracted for representing a pixelated object in a background pixel field. An object pixel is located that is the start of a new contour for the object and identifying that pixel as the first pixel of the new contour. A first contour point is then located on the mid-point of a transition edge of the first pixel. A tracing direction from the first contour point is determined for tracing the new contour. Contour points on mid-points of pixel transition edges are sequentially located along the tracing direction until the first contour point is again encountered to complete tracing the new contour. The new contour is then added to a list of extracted contours that represent the object. The contour extraction process associates regions and contours by labeling all the contours belonging to the same object with the same label.

Hazardous Waste Site Remediation, Neighborhood Change, and Neighborhood Quality.

PubMed Central

Greenberg, M; Schneider, D

1994-01-01

We tested the hypothesis that neighborhoods with hazardous waste sites may no longer be undesirable places to live if they have been at least partly remediated. We collected 377 questionnaires (42% response rate) administered from within one-half mile of the number 1, 4, and 12 hazardous waste sites on the National Priority List (Superfund). These neighborhoods were rated higher quality than neighborhoods with unremediated hazardous waste sites and about the same as neighborhoods in northern New Jersey and the United States as a whole. Newer residents considered these formerly tainted areas to be opportunities to upgrade their housing and living conditions. Long-term residents retained the negative image of the blemished neighborhood. Images p542-a PMID:9679112

Positive Neighborhood Norms Buffer Ethnic Diversity Effects on Neighborhood Dissatisfaction, Perceived Neighborhood Disadvantage, and Moving Intentions.

PubMed

Van Assche, Jasper; Asbrock, Frank; Roets, Arne; Kauff, Mathias

2018-05-01

Positive neighborhood norms, such as strong local networks, are critical to people's satisfaction with, perceived disadvantage of, and intentions to stay in their neighborhood. At the same time, local ethnic diversity is said to be detrimental for these community outcomes. Integrating both frameworks, we tested whether the negative consequences of diversity occur even when perceived social norms are positive. Study 1 ( N = 1,760 German adults) showed that perceptions of positive neighborhood norms buffered against the effects of perceived diversity on moving intentions via neighborhood satisfaction and perceived neighborhood disadvantage. Study 2 ( N = 993 Dutch adults) replicated and extended this moderated mediation model using other characteristics of diversity (i.e., objective and estimated minority proportions). Multilevel analyses again revealed consistent buffering effects of positive neighborhood norms. Our findings are discussed in light of the ongoing public and political debate concerning diversity and social and communal life.

Pulmonary parenchyma segmentation in thin CT image sequences with spectral clustering and geodesic active contour model based on similarity

NASA Astrophysics Data System (ADS)

He, Nana; Zhang, Xiaolong; Zhao, Juanjuan; Zhao, Huilan; Qiang, Yan

2017-07-01

While the popular thin layer scanning technology of spiral CT has helped to improve diagnoses of lung diseases, the large volumes of scanning images produced by the technology also dramatically increase the load of physicians in lesion detection. Computer-aided diagnosis techniques like lesions segmentation in thin CT sequences have been developed to address this issue, but it remains a challenge to achieve high segmentation efficiency and accuracy without much involvement of human manual intervention. In this paper, we present our research on automated segmentation of lung parenchyma with an improved geodesic active contour model that is geodesic active contour model based on similarity (GACBS). Combining spectral clustering algorithm based on Nystrom (SCN) with GACBS, this algorithm first extracts key image slices, then uses these slices to generate an initial contour of pulmonary parenchyma of un-segmented slices with an interpolation algorithm, and finally segments lung parenchyma of un-segmented slices. Experimental results show that the segmentation results generated by our method are close to what manual segmentation can produce, with an average volume overlap ratio of 91.48%.

Learning to Link Visual Contours

PubMed Central

Li, Wu; Piëch, Valentin; Gilbert, Charles D.

2008-01-01

SUMMARY In complex visual scenes, linking related contour elements is important for object recognition. This process, thought to be stimulus driven and hard wired, has substrates in primary visual cortex (V1). Here, however, we find contour integration in V1 to depend strongly on perceptual learning and top-down influences that are specific to contour detection. In naive monkeys the information about contours embedded in complex backgrounds is absent in V1 neuronal responses, and is independent of the locus of spatial attention. Training animals to find embedded contours induces strong contour-related responses specific to the trained retinotopic region. These responses are most robust when animals perform the contour detection task, but disappear under anesthesia. Our findings suggest that top-down influences dynamically adapt neural circuits according to specific perceptual tasks. This may serve as a general neuronal mechanism of perceptual learning, and reflect top-down mediated changes in cortical states. PMID:18255036

Challenges and complications in neighborhood mapping: from neighborhood concept to operationalization

NASA Astrophysics Data System (ADS)

Deng, Yongxin

2016-07-01

This paper examines complications in neighborhood mapping and corresponding challenges for the GIS community, taking both a conceptual and a methodological perspective. It focuses on the social and spatial dimensions of the neighborhood concept and highlights their relationship in neighborhood mapping. Following a brief summary of neighborhood definitions, five interwoven factors are identified to be origins of neighborhood mapping difficulties: conceptual vagueness, uncertainty of various sources, GIS representation, scale, and neighborhood homogeneity or continuity. Existing neighborhood mapping methods are grouped into six categories to be assessed: perception based, physically based, inference based, preexisting, aggregated, and automated. Mapping practices in various neighborhood-related disciplines and applications are cited as examples to demonstrate how the methods work, as well as how they should be evaluated. A few mapping strategies for the improvement of neighborhood mapping are prescribed from a GIS perspective: documenting simplifications employed in the mapping procedure, addressing uncertainty sources, developing new data solutions, and integrating complementary mapping methods. Incorporation of high-resolution data and introduction of more GIS ideas and methods (such as fuzzy logic) are identified to be future opportunities.

Ecological Networks and Neighborhood Social Organization1

PubMed Central

Browning, Christopher R.; Calder, Catherine A.; Soller, Brian; Jackson, Aubrey L.; Dirlam, Jonathan

2017-01-01

Drawing on the social disorganization tradition and the social ecological perspective of Jane Jacobs, the authors hypothesize that neighborhoods composed of residents who intersect in space more frequently as a result of routine activities will exhibit higher levels of collective efficacy, intergenerational closure, and social network interaction and exchange. They develop this approach employing the concept of ecological networks—two-mode networks that indirectly link residents through spatial overlap in routine activities. Using data from the Los Angeles Family and Neighborhood Survey, they find evidence that econetwork extensity (the average proportion of households in the neighborhood to which a given household is tied through any location) and intensity (the degree to which household dyads are characterized by ties through multiple locations) are positively related to changes in social organization between 2000–2001 and 2006–2008. These findings demonstrate the relevance of econetwork characteristics—heretofore neglected in research on urban neighborhoods—for consequential dimensions of neighborhood social organization. PMID:29379218

Parental perceived neighborhood attributes: associations with active transport and physical activity among 10-12 year old children and the mediating role of independent mobility.

PubMed

De Meester, Femke; Van Dyck, Delfien; De Bourdeaudhuij, Ilse; Cardon, Greet

2014-06-20

During the last decades, the use of active travel modes declined in all age groups. Childhood is a critical time to establish lifelong healthy patterns. To develop effective interventions in this age group, insight in the correlates of health behaviors and the possible mediating factors is necessary. Among children, the role of parents may not be overlooked. Therefore, this study aimed to examine the associations of parental perceptions of neighborhood environmental attributes with active transport and total physical activity in 10-12 year old Belgian boys and girls. Furthermore, this study examined the potential mediating effect of independent mobility on these associations. In the present study, 736 10-12 year old children and their parents from 44 elementary schools in Flanders, Belgium, participated. The children were asked to wear an activity monitor and to fill in a survey questioning demographic factors and the Flemish Physical Activity Questionnaire. The parents filled in a survey concerning demographic factors, the child's level of independent mobility and environmental perceptions (Neighborhood Environmental Walkability Scale). Overall, boys reported more active transport when parents perceived more land use mix diversity, shorter distances to school, good land use mix access, higher residential density and less pleasing neighborhood aesthetics. Higher total physical activity levels were reported when parents perceived shorter distances to school and availability of walking/cycling infrastructure. None of the associations was mediated by independent mobility in boys. Girls reported more active transport when parents perceived higher residential density, more land use mix diversity, shorter distances to school, good land use mix access, available walking/cycling infrastructure and convenient recreational facilities. Girls reported higher total physical activity levels when parents perceived high residential density, good land use mix access, well

CONTOUR investigation launched

NASA Astrophysics Data System (ADS)

Showstack, Randy

On 27 August, NASA Administrator Sean O'Keefe appointed a team to investigate the apparent loss of the Comet Nucleus Tour (CONTOUR) spacecraft, which stopped communicating with the mission control operations on 15 August.On that date, CONTOUR failed to communicate following the firing of its main engine that would take it out of its orbit around the Earth. Shortly afterwards, the mission team received telescope images from several observatories showing two objects traveling along the spacecraft's predicted path. Those objects could be CONTOUR, and part of the spacecraft that may have separated from it when the spacecraft's solid rocket motor fired.

Understanding neighborhood environment related to Hong Kong children's physical activity: a qualitative study using nominal group technique.

PubMed

He, Gang; Cerin, Ester; Huang, Wendy Y; Wong, Stephen H

2014-01-01

Relationships between the neighborhood environment and children's physical activity have been well documented in Western countries but are less investigated in ultra-dense Asian cities. The aim of this study was to identify the environmental facilitators and barriers of physical activity behaviors among Hong Kong Chinese children using nominal group technique. Five nominal groups were conducted among 34 children aged 10-11 years from four types of neighborhoods varying in socio-economic status and walkability in Hong Kong. Environmental factors were generated by children in response to the question "What neighborhood environments do you think would increase or decrease your willingness to do physical activity?" Factors were prioritized in order of their importance to children's physical activity. Sixteen unique environmental factors, which were perceived as the most important to children's physical activity, were identified. Factors perceived as physical activity-facilitators included "Sufficient lighting", "Bridge or tunnel", "Few cars on roads", "Convenient transportation", "Subway station", "Recreation grounds", "Shopping malls with air conditioning", "Fresh air", "Interesting animals", and "Perfume shop". Factors perceived as physical activity-barriers included "People who make me feel unsafe", "Crimes nearby", "Afraid of being taken or hurt at night", "Hard to find toilet in shopping mall", "Too much noise", and "Too many people in recreation grounds". Specific physical activity-related environmental facilitators and barriers, which are unique in an ultra-dense city, were identified by Hong Kong children. These initial findings can inform future examinations of the physical activity-environment relationship among children in Hong Kong and similar Asian cities.

Perceiving Object Shape from Specular Highlight Deformation, Boundary Contour Deformation, and Active Haptic Manipulation.

PubMed

Norman, J Farley; Phillips, Flip; Cheeseman, Jacob R; Thomason, Kelsey E; Ronning, Cecilia; Behari, Kriti; Kleinman, Kayla; Calloway, Autum B; Lamirande, Davora

2016-01-01

It is well known that motion facilitates the visual perception of solid object shape, particularly when surface texture or other identifiable features (e.g., corners) are present. Conventional models of structure-from-motion require the presence of texture or identifiable object features in order to recover 3-D structure. Is the facilitation in 3-D shape perception similar in magnitude when surface texture is absent? On any given trial in the current experiments, participants were presented with a single randomly-selected solid object (bell pepper or randomly-shaped "glaven") for 12 seconds and were required to indicate which of 12 (for bell peppers) or 8 (for glavens) simultaneously visible objects possessed the same shape. The initial single object's shape was defined either by boundary contours alone (i.e., presented as a silhouette), specular highlights alone, specular highlights combined with boundary contours, or texture. In addition, there was a haptic condition: in this condition, the participants haptically explored with both hands (but could not see) the initial single object for 12 seconds; they then performed the same shape-matching task used in the visual conditions. For both the visual and haptic conditions, motion (rotation in depth or active object manipulation) was present in half of the trials and was not present for the remaining trials. The effect of motion was quantitatively similar for all of the visual and haptic conditions-e.g., the participants' performance in Experiment 1 was 93.5 percent higher in the motion or active haptic manipulation conditions (when compared to the static conditions). The current results demonstrate that deforming specular highlights or boundary contours facilitate 3-D shape perception as much as the motion of objects that possess texture. The current results also indicate that the improvement with motion that occurs for haptics is similar in magnitude to that which occurs for vision.

Perceiving Object Shape from Specular Highlight Deformation, Boundary Contour Deformation, and Active Haptic Manipulation

PubMed Central

Cheeseman, Jacob R.; Thomason, Kelsey E.; Ronning, Cecilia; Behari, Kriti; Kleinman, Kayla; Calloway, Autum B.; Lamirande, Davora

2016-01-01

It is well known that motion facilitates the visual perception of solid object shape, particularly when surface texture or other identifiable features (e.g., corners) are present. Conventional models of structure-from-motion require the presence of texture or identifiable object features in order to recover 3-D structure. Is the facilitation in 3-D shape perception similar in magnitude when surface texture is absent? On any given trial in the current experiments, participants were presented with a single randomly-selected solid object (bell pepper or randomly-shaped “glaven”) for 12 seconds and were required to indicate which of 12 (for bell peppers) or 8 (for glavens) simultaneously visible objects possessed the same shape. The initial single object’s shape was defined either by boundary contours alone (i.e., presented as a silhouette), specular highlights alone, specular highlights combined with boundary contours, or texture. In addition, there was a haptic condition: in this condition, the participants haptically explored with both hands (but could not see) the initial single object for 12 seconds; they then performed the same shape-matching task used in the visual conditions. For both the visual and haptic conditions, motion (rotation in depth or active object manipulation) was present in half of the trials and was not present for the remaining trials. The effect of motion was quantitatively similar for all of the visual and haptic conditions–e.g., the participants’ performance in Experiment 1 was 93.5 percent higher in the motion or active haptic manipulation conditions (when compared to the static conditions). The current results demonstrate that deforming specular highlights or boundary contours facilitate 3-D shape perception as much as the motion of objects that possess texture. The current results also indicate that the improvement with motion that occurs for haptics is similar in magnitude to that which occurs for vision. PMID:26863531

Dog-walking and sense of community in neighborhoods: implications for promoting regular physical activity in adults 50 years and older.

PubMed

Toohey, A M; McCormack, G R; Doyle-Baker, P K; Adams, C L; Rock, M J

2013-07-01

This study investigates whether dog-ownership and neighborhood characteristics are associated with sense of community (SC) and neighborhood-based recreational walking (NRW) for older adults. A random sample of adults ≥50 years of age (n=884) provided information on SC, dog-related factors, neighborhood walking, and socio-demographics in telephone and postal surveys. Associations between dog-ownership, neighborhood characteristics, and NRW were estimated using logistic regression (i.e., odds ratios (OR)). Frequent dog-walkers (≥4 times/wk) were more likely than those not owning a dog to report a heightened SC (OR=1.94, p<.05) and to achieve ≥150min/wk of NRW (OR=10.68, p<.05). SC was also tested but not found to mediate associations between neighborhood characteristics, dog-ownership and NRW. Older adults who walk dogs often in their neighborhoods may benefit from both increased physical activity and heightened sense of community to an extent that supports healthy aging. Longitudinal studies are needed to explore directions of associations among these factors. Copyright © 2013 Elsevier Ltd. All rights reserved.

Topological Cacti: Visualizing Contour-based Statistics

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

Weber, Gunther H.; Bremer, Peer-Timo; Pascucci, Valerio

2011-05-26

Contours, the connected components of level sets, play an important role in understanding the global structure of a scalar field. In particular their nestingbehavior and topology-often represented in form of a contour tree-have been used extensively for visualization and analysis. However, traditional contour trees onlyencode structural properties like number of contours or the nesting of contours, but little quantitative information such as volume or other statistics. Here we use thesegmentation implied by a contour tree to compute a large number of per-contour (interval) based statistics of both the function defining the contour tree as well asother co-located functions. We introducemore » a new visual metaphor for contour trees, called topological cacti, that extends the traditional toporrery display of acontour tree to display additional quantitative information as width of the cactus trunk and length of its spikes. We apply the new technique to scalar fields ofvarying dimension and different measures to demonstrate the effectiveness of the approach.« less

Generic and robust method for automatic segmentation of PET images using an active contour model

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

Zhuang, Mingzan

Purpose: Although positron emission tomography (PET) images have shown potential to improve the accuracy of targeting in radiation therapy planning and assessment of response to treatment, the boundaries of tumors are not easily distinguishable from surrounding normal tissue owing to the low spatial resolution and inherent noisy characteristics of PET images. The objective of this study is to develop a generic and robust method for automatic delineation of tumor volumes using an active contour model and to evaluate its performance using phantom and clinical studies. Methods: MASAC, a method for automatic segmentation using an active contour model, incorporates the histogrammore » fuzzy C-means clustering, and localized and textural information to constrain the active contour to detect boundaries in an accurate and robust manner. Moreover, the lattice Boltzmann method is used as an alternative approach for solving the level set equation to make it faster and suitable for parallel programming. Twenty simulated phantom studies and 16 clinical studies, including six cases of pharyngolaryngeal squamous cell carcinoma and ten cases of nonsmall cell lung cancer, were included to evaluate its performance. Besides, the proposed method was also compared with the contourlet-based active contour algorithm (CAC) and Schaefer’s thresholding method (ST). The relative volume error (RE), Dice similarity coefficient (DSC), and classification error (CE) metrics were used to analyze the results quantitatively. Results: For the simulated phantom studies (PSs), MASAC and CAC provide similar segmentations of the different lesions, while ST fails to achieve reliable results. For the clinical datasets (2 cases with connected high-uptake regions excluded) (CSs), CAC provides for the lowest mean RE (−8.38% ± 27.49%), while MASAC achieves the best mean DSC (0.71 ± 0.09) and mean CE (53.92% ± 12.65%), respectively. MASAC could reliably quantify different types of lesions assessed in

Contoured Surface Eddy Current Inspection System

DOEpatents

Batzinger, Thomas James; Fulton, James Paul; Rose, Curtis Wayne; Perocchi, Lee Cranford

2003-04-08

Eddy current inspection of a contoured surface of a workpiece is performed by forming a backing piece of flexible, resiliently yieldable material with a contoured exterior surface conforming in shape to the workpiece contoured surface. The backing piece is preferably cast in place so as to conform to the workpiece contoured surface. A flexible eddy current array probe is attached to the contoured exterior surface of the backing piece such that the probe faces the contoured surface of the workpiece to be inspected when the backing piece is disposed adjacent to the workpiece. The backing piece is then expanded volumetrically by inserting at least one shim into a slot in the backing piece to provide sufficient contact pressure between the probe and the workpiece contoured surface to enable the inspection of the workpiece contoured surface to be performed.

Automatic media-adventitia IVUS image segmentation based on sparse representation framework and dynamic directional active contour model.

PubMed

Zakeri, Fahimeh Sadat; Setarehdan, Seyed Kamaledin; Norouzi, Somayye

2017-10-01

Segmentation of the arterial wall boundaries from intravascular ultrasound images is an important image processing task in order to quantify arterial wall characteristics such as shape, area, thickness and eccentricity. Since manual segmentation of these boundaries is a laborious and time consuming procedure, many researchers attempted to develop (semi-) automatic segmentation techniques as a powerful tool for educational and clinical purposes in the past but as yet there is no any clinically approved method in the market. This paper presents a deterministic-statistical strategy for automatic media-adventitia border detection by a fourfold algorithm. First, a smoothed initial contour is extracted based on the classification in the sparse representation framework which is combined with the dynamic directional convolution vector field. Next, an active contour model is utilized for the propagation of the initial contour toward the interested borders. Finally, the extracted contour is refined in the leakage, side branch openings and calcification regions based on the image texture patterns. The performance of the proposed algorithm is evaluated by comparing the results to those manually traced borders by an expert on 312 different IVUS images obtained from four different patients. The statistical analysis of the results demonstrates the efficiency of the proposed method in the media-adventitia border detection with enough consistency in the leakage and calcification regions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Energy Expenditure associated with the use of neighborhood parks in 2 cities

Treesearch

Luis J. Suau; Myron F. Floyd; John O. Spengler; Jay E. Maddock; Paul H. Gobster

2012-01-01

Context: Availability of public neighborhood parks is associated with physical activity. Little is known about how parks contribute to population energy balance. Purpose: This study estimated energy expenditure associated with the use of neighborhood parks and compared energy expenditure by activity areas within parks and by neighborhood race/ethnicity and income....

Healthy neighborhoods: walkability and air pollution.

PubMed

Marshall, Julian D; Brauer, Michael; Frank, Lawrence D

2009-11-01

The built environment may influence health in part through the promotion of physical activity and exposure to pollution. To date, no studies have explored interactions between neighborhood walkability and air pollution exposure. We estimated concentrations of nitric oxide (NO), a marker for direct vehicle emissions), and ozone (O(3)) and a neighborhood walkability score, for 49,702 (89% of total) postal codes in Vancouver, British Columbia, Canada. NO concentrations were estimated from a land-use regression model, O(3) was estimated from ambient monitoring data; walkability was calculated based on geographic attributes such as land-use mix, street connectivity, and residential density. All three attributes exhibit an urban-rural gradient, with high walkability and NO concentrations, and low O(3) concentrations, near the city center. Lower-income areas tend to have higher NO concentrations and walkability and lower O(3) concentrations. Higher-income areas tend to have lower pollution (NO and O(3)). "Sweet-spot" neighborhoods (low pollution, high walkability) are generally located near but not at the city center and are almost exclusively higher income. Increased concentration of activities in urban settings yields both health costs and benefits. Our research identifies neighborhoods that do especially well (and especially poorly) for walkability and air pollution exposure. Work is needed to ensure that the poor do not bear an undue burden of urban air pollution and that neighborhoods designed for walking, bicycling, or mass transit do not adversely affect resident's exposure to air pollution. Analyses presented here could be replicated in other cities and tracked over time to better understand interactions among neighborhood walkability, air pollution exposure, and income level.

One size doesn't fit all: cross-sectional associations between neighborhood walkability, crime and physical activity depends on age and sex of residents.

PubMed

Richardson, Andrea S; Troxel, Wendy M; Ghosh-Dastidar, Madhumita B; Beckman, Robin; Hunter, Gerald P; DeSantis, Amy S; Colabianchi, Natalie; Dubowitz, Tamara

2017-01-19

Low-income African American adults are disproportionately affected by obesity and are also least likely to engage in recommended levels of physical activity (Flegal et al. JAMA 303(3):235-41, 2010; Tucker et al. Am J Prev Med 40(4):454-61, 2011). Moderate-to-vigorous physical activity (MVPA) is an important factor for weight management and control, as well as for reducing disease risk (Andersen et al. Lancet 368(9532):299-304, 2006; Boreham and Riddoch J Sports Sci 19(12):915-29, 2001; Carson et al. PLoS One 8(8):e71417, 2013). While neighborhood greenspace and walkability have been associated with increased MVPA, evidence also suggests that living in areas with high rates of crime limits MVPA. Few studies have examined to what extent the confluence of neighborhood greenspace, walkability and crime might impact MVPA in low-income African American adults nor how associations may vary by age and sex. In 2013 we collected self-reported data on demographics, functional limitations, objective measures of MVPA (accelerometry), neighborhood greenspace (geographic information system), and walkability (street audit) in 791 predominantly African-American adults (mean age 56 years) living in two United States (U.S.) low-income neighborhoods. We also acquired data from the City of Pittsburgh on all crime events within both neighborhoods. To examine cross-sectional associations of neighborhood-related variables (i.e., neighborhood greenspace, walkability and crime) with MVPA, we used zero-inflated negative binomial regression models. Additionally, we examined potential interactions by age (over 65 years) and sex on relationships between neighborhood variables and MVPA. Overall, residents engaged in very little to no MVPA regardless of where they lived. However, for women, but not men, under the age of 65 years, living in more walkable neighborhoods was associated with more time engaged in MVPA in (β = 0.55, p = 0.007) as compared to their counterparts living in less

Perceptions as the crucial link? The mediating role of neighborhood perceptions in the relationship between the neighborhood context and neighborhood cohesion.

PubMed

Laméris, Joran; Hipp, John R; Tolsma, Jochem

2018-05-01

This study examines the effects of neighborhood racial in-group size, economic deprivation and the prevalence of crime on neighborhood cohesion among U.S. whites. We explore to what extent residents' perceptions of their neighborhood mediate these macro-micro relationships. We use a recent individual-level data set, the American Social Fabric Study (2012/2013), enriched with contextual-level data from the U.S. Census Bureau (2010) and employ multi-level structural equation models. We show that the racial in-group size is positively related to neighborhood cohesion and that neighborhood cohesion is lower in communities with a high crime rate. Individuals' perceptions of the racial in-group size partly mediate the relationship between the objective racial in-group size and neighborhood cohesion. Residents' perceptions of unsafety from crime also appear to be a mediating factor, not only for the objective crime rate but also for the objective racial in-group size. This is in line with our idea that racial stereotypes link racial minorities to crime whereby neighborhoods with a large non-white population are perceived to be more unsafe. Residents of the same neighborhood differ in how they perceive the degree of economic decay of the neighborhood and this causes them to evaluate neighborhood cohesion differently, however perceptions of neighborhood economic decay do not explain the link between the objective neighborhood context and neighborhood cohesion. Copyright © 2018. Published by Elsevier Inc.

Neighborhood Design for Walking and Biking

PubMed Central

Brown, Barbara B.; Smith, Ken R.; Hanson, Heidi; Fan, Jessie X.; Kowaleski-Jones, Lori; Zick, Cathleen D.

2013-01-01

Background Neighborhood designs often relate to physical activity and to BMI. Purpose Does neighborhood walkability/bikeability relate to BMI and obesity risk and does moderate-to-vigorous physical activity (MVPA) account for some of the relationship? Methods Census 2000 provided walkability/bikeability measures—block group proportions of workers who walk or bike to work, housing age, and population density—and National Health and Nutrition Examination Study (NHANES 2003–2006) provided MVPA accelerometer measures. Regression analyses (2011–2012) adjusted for geographic clustering and multiple control variables. Results Greater density and older housing were associated with lower male BMI in bivariate analyses, but there were no density and housing age effects in multivariate models. For women, greater proportions of neighborhood workers who walk to work (M=0.02) and more MVPA was associated with lower BMI and lower obesity risk. For men, greater proportions of workers who bike to work (M=0.004) and more MVPA was associated with lower BMI and obesity risk. For both effects, MVPA partially mediated the relationships between walkability/bikeability and BMI. If such associations are causal, doubling walk and bike-to-work proportions (to 0.04 and 0.008) would have –0.3 and –0.33 effects on the average BMIs of adult women and men living in the neighborhood. This equates to 1.5 lbs for a 64” woman and 2.3 lbs for a 69” man. Conclusions Although walking/biking to work is rare in the U.S., greater proportions of such workers in neighborhoods relate to lower weight and higher MVPA. Bikeability merits greater attention as a modifiable activity-friendliness factor, particularly for men. PMID:23415119

Neighborhood solutions for neighborhood problems: an empirically based violence prevention collaboration.

PubMed

Randall, J; Swenson, C C; Henggeler, S W

1999-12-01

Youth antisocial behavior is influenced, in part, by neighborhood context. Yet, rather than attempting to ameliorate factors contributing to youth antisocial behavior, service dollars are primarily devoted to expensive and often ineffective out-of-home placements. This article describes the development and implementation of a collaborative partnership designed to empower an economically disadvantaged neighborhood to address violent criminal behavior, substance abuse, and other serious antisocial problems of its youth while maintaining youth in the neighborhood. Through a collaboration between a university research center and neighborhood stakeholders, services are being provided to address the key priorities identified by neighborhood residents, and extensive efforts are being made to develop family and neighborhood contexts that are conducive to prosocial youth behavior.

Examining the individual and perceived neighborhood associations of leisure-time physical activity in persons with spinal cord injury.

PubMed

Arbour-Nicitopoulos, Kelly P; Martin Ginis, Kathleen A; Wilson, Philip M

2010-05-01

Theory of Planned Behavior (TPB) constructs have been shown to be useful for explaining leisure-time physical activity (LTPA) in persons with spinal cord injury (SCI). However, other factors not captured by the TPB may also be important predictors of LTPA for this population. The purpose of this study is to examine the role of neighborhood perceptions within the context of the TPB for understanding LTPA in persons living with SCI. This is a cross-sectional analysis (n = 574) using structural equation modeling involving measures of the TPB constructs, perceived neighborhood esthetics and sidewalks, and LTPA. TPB constructs explained 57% of the variance in intentions and 12% of the variance in behavior. Inclusion of the neighborhood variables to the model resulted in an additional 1% of the variance explained in intentions, with esthetics exhibiting significant positive relationships with the TPB variables. Integrating perceived neighborhood esthetics into the TPB framework provides additional understanding of LTPA intentions in persons living with SCI.

Association Between the Built Environment in School Neighborhoods With Physical Activity Among New York City Children, 2012

PubMed Central

Gray, Heewon Lee; Quinn, James; Rundle, Andrew G.; Contento, Isobel R.; Koch, Pamela A.

2016-01-01

Introduction The benefits of physical activity for health and well-being are well established, yet built environment characteristics in the school neighborhood may constrain students’ ability to engage in physical activity and contribute to the considerable variation in physical activity among students at different schools. Methods Baseline data from the Food, Health and Choices obesity prevention trial were used to create multilevel linear models of the relationship between fifth-grade students’ (n = 952) physical activity and related psychosocial factors and characteristics of the built environment of the school’s neighborhood (park access, public transportation density, total crime, and walkability), controlling for age and body mass index z scores. Results Total crime was inversely associated with boys’ light physical activity duration (β = −0.189; P = .02) and behavioral intention for physical activity (β = −0.178; P = .03). Boys’ habit strength for physical activity was positively associated with public transportation density (β = 0.375; P = .02) and negatively associated with total crime (β = −0.216; P = .01), explaining 67% of between-school variation. Girls’ frequency of light physical activity was positively associated with park access (β = 0.188; P = .04). Built environment characteristics explained 97% of the between-school variation in girls’ self-efficacy in walking for exercise. Conclusions Characteristics of the built environment surrounding schools were associated with and explain between-school variation in students’ physical activity and several theory-based psychosocial factors. Partnerships between public health practitioners, policy makers, and school administrators may be warranted to shape the school neighborhood, specifically to decrease crime rates and increase park access, to encourage physical activity in youth. PMID:27536902

The price of access: capitalization of neighborhood contextual factors

PubMed Central

2013-01-01

Background Studies of neighborhood context on health behavior have not considered that the health benefits of context may be ‘capitalized’ into, or included in, higher housing values. This study examines the associations of better neighborhood context with neighborhood housing values. Methods We use the third wave of Add Health (2000-2001) to estimate the association of neighborhood contextual variables and housing values first across then within income types. This is a census block group-level analysis. Results We find that neighborhood context, especially access to fruit and vegetable outlets, is capitalized into, or associated with, higher housing values. Fast food and convenience store access are associated with lower housing values. Capitalization differs by income quartile of the neighborhood. Even those in the poorest neighborhoods value access to fresh fruits and vegetables, and those in the wealthier neighborhoods value activity resources. All neighborhood incomes types place negative value on fast food access and convenience store access. Conclusions Access to health-related contextual attributes is capitalized into higher housing prices. Access to fresh fruits and vegetables is valued in neighborhoods of all income levels. Modeling these associations by neighborhood income levels helps explain the mixed results in the literature on the built environment in terms of linking health outcomes to access. PMID:23927010

Neighborhoods and Adolescent Health-Risk Behavior: An Ecological Network Approach1

PubMed Central

Browning, Christopher R.; Soller, Brian; Jackson, Aubrey L.

2014-01-01

This study integrates insights from social network analysis, activity space perspectives, and theories of urban and spatial processes to present an innovative approach to neighborhood effects on health-risk behavior among youth. We suggest spatial patterns of neighborhood residents’ non-home routine activities may be conceptualized as ecological, or “eco”-networks, which are two-mode networks that indirectly link residents through socio-spatial overlap in routine activities. We further argue structural configurations of eco-networks are consequential for youth’s behavioral health. In this study we focus on a key structural feature of eco-networks—the neighborhood-level extent to which households share two or more activity locations, or eco-network reinforcement—and its association with two dimensions of health-risk behavior, substance use and delinquency/sexual activity. Using geographic data on non-home routine activity locations among respondents from the Los Angeles Family and Neighborhood Survey (L.A.FANS), we constructed neighborhood-specific eco-networks by connecting sampled households to “activity clusters,” which are sets of spatially-proximate activity locations. We then measured eco-network reinforcement and examined its association with adolescent dimensions of health risk behavior employing a sample of 830 youth ages 12-17 nested in 65 census tracts. We also examined whether neighborhood-level social processes (collective efficacy and intergenerational closure) mediate the association between eco-network reinforcement and the outcomes considered. Results indicated eco-network reinforcement exhibits robust negative associations with both substance use and delinquency/sexual activity scales. Eco-network reinforcement effects were not explained by potential mediating variables. In addition to introducing a novel theoretical and empirical approach to neighborhood effects on youth, our findings highlight the importance of eco

Quantifying the contribution of neighborhood parks to physical activity.

PubMed

Han, Bing; Cohen, Deborah; McKenzie, Thomas L

2013-11-01

To quantify the contribution of U.S. neighborhood parks to the time spent in moderate-to-vigorous physical activity (MVPA) by the local population. Observational data on the use of 10 parks in five US cities collected during summer and fall 2008 were analyzed by a model-averaging approach. Estimated MVPA time accrued in parks was compared to estimated total MVPA time accrued by the local population, based upon national estimates. On average, parks provided roughly 4000hours of use and 1500 MVPA hours per week. Park use accounted for approximately 50% of the vigorous physical activity (VPA) time of those living within 0.5 miles of the park and 16% of those living within 1.0 miles of the park. Parks accounted for a modest proportion of moderate physical activity (MPA) time, about 14% and 4% for those living within 0.5 miles and 1.0 miles of the park, respectively. Parks have significant roles in supporting vigorous physical activity of the local population. Because they are underutilized and vigorous activity is critical to child development and adult physical fitness, efforts should be made to promote vigorous activity within local parks. © 2013.

GENERALIZED DIGITAL CONTOURING PROGRAM

NASA Technical Reports Server (NTRS)

Jones, R. L.

1994-01-01

This is a digital computer contouring program developed by combining desirable characteristics from several existing contouring programs. It can easily be adapted to many different research requirements. The overlaid structure of the program permits desired modifications to be made with ease. The contouring program performs both the task of generating a depth matrix from either randomly or regularly spaced surface heights and the task of contouring the data. Each element of the depth matrix is computed as a weighted mean of heights predicted at an element by planes tangent to the surface at neighboring control points. Each contour line is determined by its intercepts with the sides of geometrical figures formed by connecting the various elements of the depth matrix with straight lines. Although contour charts are usually thought of as being two-dimensional pictorial representations of topographic formations of land masses, they can also be useful in portraying data which are obtained during the course of research in various scientific disciplines and which would ordinarily be tabulated. Any set of data which can be referenced to a two-dimensional coordinate system can be graphically represented by this program. This program is written in FORTRAN IV and ASSEMBLER for batch execution and has been implemented on the CDC 6000 Series. This program was developed in 1971.

The Safety of the Neighborhood Environment and Physical Activity in Czech and Polish Adolescents

PubMed Central

Sas-Nowosielski, Krzysztof; Frömel, Karel

2018-01-01

(1) Background: An increase in or at least the sustainment of walking activities across a wide section of the population is a crucial health-related task for Central and East European countries. The aim of this study was to assess the associations between adolescents’ walking activities and various levels of perceived safety of the built environment in differing socio-demographic backgrounds of Poland and the Czech Republic. Furthermore, we aimed to determine major moderators affecting the walking habits of adolescents in areas with different levels of walkability. (2) Methods: The surveys were conducted during the 2008–2009 and 2013–2014 school years in 24 Polish and 35 Czech secondary schools, with a sample of 2001 adolescents. All participants completed the International Physical Activity Questionnaire–Long Form and the NEWS–Abbreviated. Selected students took part in objective weekly monitoring of physical activity (PA). (3) Results: Boys and girls who perceived their neighborhood environment as the safest were significantly more likely to meet the recommendations for leisure-time walking. Adolescents from the safest environment achieved 11,024 steps/day on average, while those from the least safe environment achieved 9686 steps/day. (4) Conclusions: A safe neighborhood environment significantly predicts walking activities among girls. Environmental safety improvement can support the active transport and better use of leisure time PA. PMID:29329276

The Safety of the Neighborhood Environment and Physical Activity in Czech and Polish Adolescents.

PubMed

Mitáš, Josef; Sas-Nowosielski, Krzysztof; Groffik, Dorota; Frömel, Karel

2018-01-12

(1) Background : An increase in or at least the sustainment of walking activities across a wide section of the population is a crucial health-related task for Central and East European countries. The aim of this study was to assess the associations between adolescents' walking activities and various levels of perceived safety of the built environment in differing socio-demographic backgrounds of Poland and the Czech Republic. Furthermore, we aimed to determine major moderators affecting the walking habits of adolescents in areas with different levels of walkability. (2) Methods : The surveys were conducted during the 2008-2009 and 2013-2014 school years in 24 Polish and 35 Czech secondary schools, with a sample of 2001 adolescents. All participants completed the International Physical Activity Questionnaire-Long Form and the NEWS-Abbreviated. Selected students took part in objective weekly monitoring of physical activity (PA). (3) Results : Boys and girls who perceived their neighborhood environment as the safest were significantly more likely to meet the recommendations for leisure-time walking. Adolescents from the safest environment achieved 11,024 steps/day on average, while those from the least safe environment achieved 9686 steps/day. (4) Conclusions : A safe neighborhood environment significantly predicts walking activities among girls. Environmental safety improvement can support the active transport and better use of leisure time PA.

Lung segmentation from HRCT using united geometric active contours

NASA Astrophysics Data System (ADS)

Liu, Junwei; Li, Chuanfu; Xiong, Jin; Feng, Huanqing

2007-12-01

Accurate lung segmentation from high resolution CT images is a challenging task due to various detail tracheal structures, missing boundary segments and complex lung anatomy. One popular method is based on gray-level threshold, however its results are usually rough. A united geometric active contours model based on level set is proposed for lung segmentation in this paper. Particularly, this method combines local boundary information and region statistical-based model synchronously: 1) Boundary term ensures the integrality of lung tissue.2) Region term makes the level set function evolve with global characteristic and independent on initial settings. A penalizing energy term is introduced into the model, which forces the level set function evolving without re-initialization. The method is found to be much more efficient in lung segmentation than other methods that are only based on boundary or region. Results are shown by 3D lung surface reconstruction, which indicates that the method will play an important role in the design of computer-aided diagnostic (CAD) system.

Perceived and Objective Measures of Neighborhood Walkability and Physical Activity among Adults in Japan: A Multilevel Analysis of a Nationally Representative Sample.

PubMed

Hanibuchi, Tomoya; Nakaya, Tomoki; Yonejima, Mayuko; Honjo, Kaori

2015-10-23

Although associations between a person's neighborhood and their health have been studied internationally, most studies have been limited to a few cities or towns. Therefore, we used a nationally representative sample to explore whether perceived and objective neighborhood walkability was associated with the physical activity of residents. Data were analyzed from the Japanese General Social Surveys of 2010 (n = 2395; 1114 men and 1281 women). Perceived walkability was scored using factor analysis for the respondents' perceptions of neighborhood conditions, while objective walkability was measured using the geographic information system approach. Finally, multilevel logistic regression analysis was performed to examine whether neighborhood walkability was associated with the frequency of leisure-time physical activity (LTPA) among respondents. We found that perceived walkability was positively associated with the frequency of LTPA (odds ratio of the highest quartile was 1.53 (1.14-2.05) compared with the lowest quartile); however, objective walkability showed no association. When stratified by gender, an association between perceived walkability and LTPA was observed among women, but only a marginally significant association was present between objective walkability and LTPA among men. We conclude that the association between neighborhood walkability and LTPA can be partially generalized across Japan.

Mister Rogers' Plan & Play Book: Activities from Mister Rogers' Neighborhood for Parents & Child Care Providers. Fourth Edition.

ERIC Educational Resources Information Center

Family Communications, Inc., Pittsburgh, PA.

Intended for both childcare professionals and parents, this book lists activities from episodes of Mister Rogers' Neighborhood television program, and can be used with or without watching the program. Each activity is assigned a number which corresponds to the television episode in which the activity is featured, and a national PBS Broadcast…

Relationships between Neighborhood Walkability and Objectively Measured Physical Activity Levels in Hemodialysis Patients.

PubMed

Han, Maggie; Ye, Xiaoling; Preciado, Priscila; Williams, Schantel; Campos, Israel; Bonner, Marcee; Young, Candace; Marsh, Daniel; Larkin, John W; Usvyat, Len A; Maddux, Franklin W; Pecoits-Filho, Roberto; Kotanko, Peter

2018-01-01

Neighborhood walkability is associated with indicators of health in the general population. We explored the association between neighborhood walkability and daily steps in hemodialysis (HD) patients. We measured daily steps over 5 weeks using Fitbit Flex (Fitbit, San Francisco, CA, USA) and retrieved Walk Score® (WS) data by patient's home ZIP code (www.walkscore.com; 0 = poorest walkability; 100 = greatest walkability). HD patients took a mean of 6,393 ± 3,550 steps/day (n = 46). Median WS of the neighborhood where they resided was 28. Patients in an above-median WS (n = 27) neighborhood took significantly more daily steps compared to those (n = 19) in a below-median WS neighborhood (7,514 ± 3,900 vs. 4,800 ± 2,228 steps/day; p < 0.001, t test). Daily steps and WS were directly correlated (R = 0.425; p = 0.0032, parametric test; R = 0.359, p = 0.0143, non-parametric test). This is the first study conducted among HD patients to indicate a direct relationship between neighborhood walkability and the actual steps taken. These results should be considered when designing initiatives to increase and improvise exercise routines in HD populations. © 2018 S. Karger AG, Basel.

Automated consensus contour building for prostate MRI.

PubMed

Khalvati, Farzad

2014-01-01

Inter-observer variability is the lack of agreement among clinicians in contouring a given organ or tumour in a medical image. The variability in medical image contouring is a source of uncertainty in radiation treatment planning. Consensus contour of a given case, which was proposed to reduce the variability, is generated by combining the manually generated contours of several clinicians. However, having access to several clinicians (e.g., radiation oncologists) to generate a consensus contour for one patient is costly. This paper presents an algorithm that automatically generates a consensus contour for a given case using the atlases of different clinicians. The algorithm was applied to prostate MR images of 15 patients manually contoured by 5 clinicians. The automatic consensus contours were compared to manual consensus contours where a median Dice similarity coefficient (DSC) of 88% was achieved.

Detecting neighborhood vacancy level in Detroit city using remote sensing

NASA Astrophysics Data System (ADS)

Li, X.; Wang, R.; Yang, A.; Vojnovic, I.

2015-12-01

With the decline of manufacturing industries, many Rust Belt cities, which enjoyed prosperity in the past, are now suffering from financial stress, population decrease and urban poverty. As a consequence, urban neighborhoods deteriorate. Houses are abandoned and left to decay. Neighborhood vacancy brings on many problems. Governments and agencies try to survey the vacancy level by going through neighborhoods and record the condition of each structure, or by buying information of active mailing addresses to get approximate neighborhood vacancy rate. But these methods are expensive and time consuming. Remote sensing provides a quick and comparatively cost-efficient way to access spatial information on social and demographical attributes of urban area. In our study, we use remote sensing to detect a major aspect of neighborhood deterioration, the vacancy levels of neighborhoods in Detroit city. We compared different neighborhoods using Landsat 8 images in 2013. We calculated NDVI that indicates the greenness of neighborhoods with the image in July 2013. Then we used thermal infrared information from image in February to detect human activities. In winter, abandoned houses will not consume so much energy and therefore neighborhoods with more abandoned houses will have smaller urban heat island effect. Controlling for the differences in terms of the greenness obtained from summer time image, we used thermal infrared from winter image to determine the temperatures of urban surface. We find that hotter areas are better maintained and have lower house vacancy rates. We also compared the changes over time for neighborhoods using Landsat 7 images from 2003 to 2013. The results show that deteriorated neighborhoods have increased NDVI in summer and get colder in winter due to abandonment of houses. Our results show the potential application of remote sensing as an easily accessed and efficient way to obtain data about social conditions in cities. We used the neighborhood

Associations Between Parent-Perceived Neighborhood Safety and Encouragement and Child Outdoor Physical Activity Among Low-Income Children.

PubMed

Nicksic, Nicole E; Salahuddin, Meliha; Butte, Nancy F; Hoelscher, Deanna M

2018-05-01

A growing body of research has examined the relationship between perceived neighborhood safety and parental encouragement for child physical activity (PA), yet these potential predictors have not been studied together to predict child outdoor PA. The purpose of this study is to examine these predictors and parent- and child-reported child outdoor PA. The Texas Childhood Obesity Research Demonstration study collected data from fifth-grade students attending 31 elementary schools across Austin and Houston and their parents (N = 748 parent-child dyads). Mixed-effects linear and logistic regressions stratified by gender and adjusted for sociodemographic covariates assessed associations among parental-perceived neighborhood safety, parental encouragement for child's outdoor PA, and parent- and child-reported child's outdoor PA. Parental-perceived neighborhood safety was significantly associated with encouraging outdoor PA (P = .01) and child-reported child's outdoor PA in boys, but not in girls. Significant associations were found between parental encouragement and child-reported outdoor PA for girls (P < .05) and parent-reported outdoor PA (P < .01) for boys and girls. Parent encouragement of PA and neighborhood safety are potential predictors of child outdoor PA and could be targeted in youth PA interventions.

Urban Poverty and Neighborhood Effects on Crime: Incorporating Spatial and Network Perspectives

PubMed Central

Graif, Corina; Gladfelter, Andrew S.; Matthews, Stephen A.

2015-01-01

Research on neighborhoods and crime is on a remarkable growth trajectory. In this article, we survey important recent developments in the scholarship on neighborhood effects and the spatial stratification of poverty and urban crime. We advance the case that, in understanding the impact of neighborhoods and poverty on crime, sociological and criminological research would benefit from expanding the analytical focus from residential neighborhoods to the network of neighborhoods individuals are exposed to during their daily routine activities. This perspective is supported by reemerging scholarship on activity spaces and macro-level research on inter-neighborhood connections. We highlight work indicating that non-residential contexts add variation in criminogenic exposure, which in turn influence offending behavior and victimization risk. Also, we draw on recent insights from research on gang violence, social and institutional connections, and spatial mismatch, and call for advancements in the scholarship on urban poverty that investigates the salience of inter-neighborhood connections in evaluating the spatial stratification of criminogenic risk for individuals and communities. PMID:27375773

Marriage and parenthood in relation to obesogenic neighborhood trajectories: The CARDIA Study

PubMed Central

Boone-Heinonen, Janne; Howard, Annie Green; Meyer, Katie; Lewis, Cora E.; Kiefe, Catarina I.; Laroche, Helena H.; Gunderson, Erica P.; Gordon-Larsen, Penny

2015-01-01

Marriage and parenthood are associated with weight gain and residential mobility. Little is known about how obesity-relevant environmental contexts differ according to family structure. We estimated trajectories of neighborhood poverty, population density, and density of fast food restaurants, supermarkets, and commercial and public physical activity facilities for adults from a biracial cohort (CARDIA, n=4,174, aged 25–50) over 13 years (1992–93 through 2005–06) using latent growth curve analysis. We estimated associations of marriage, parenthood, and race with the observed neighborhood trajectories. Married participants tended to live in neighborhoods with lower poverty, population density, and availability of all types of food and physical activity amenities. Parenthood was similarly but less consistently related to neighborhood characteristics. Marriage and parenthood were more strongly related to neighborhood trajectories in whites (versus blacks), who, in prior studies, exhibit weaker associations between neighborhood characteristics and health. Greater understanding of how interactive family and neighborhood environments contribute to healthy living is needed. PMID:26093081

Kidney segmentation in CT sequences using graph cuts based active contours model and contextual continuity.

PubMed

Zhang, Pin; Liang, Yanmei; Chang, Shengjiang; Fan, Hailun

2013-08-01

Accurate segmentation of renal tissues in abdominal computed tomography (CT) image sequences is an indispensable step for computer-aided diagnosis and pathology detection in clinical applications. In this study, the goal is to develop a radiology tool to extract renal tissues in CT sequences for the management of renal diagnosis and treatments. In this paper, the authors propose a new graph-cuts-based active contours model with an adaptive width of narrow band for kidney extraction in CT image sequences. Based on graph cuts and contextual continuity, the segmentation is carried out slice-by-slice. In the first stage, the middle two adjacent slices in a CT sequence are segmented interactively based on the graph cuts approach. Subsequently, the deformable contour evolves toward the renal boundaries by the proposed model for the kidney extraction of the remaining slices. In this model, the energy function combining boundary with regional information is optimized in the constructed graph and the adaptive search range is determined by contextual continuity and the object size. In addition, in order to reduce the complexity of the min-cut computation, the nodes in the graph only have n-links for fewer edges. The total 30 CT images sequences with normal and pathological renal tissues are used to evaluate the accuracy and effectiveness of our method. The experimental results reveal that the average dice similarity coefficient of these image sequences is from 92.37% to 95.71% and the corresponding standard deviation for each dataset is from 2.18% to 3.87%. In addition, the average automatic segmentation time for one kidney in each slice is about 0.36 s. Integrating the graph-cuts-based active contours model with contextual continuity, the algorithm takes advantages of energy minimization and the characteristics of image sequences. The proposed method achieves effective results for kidney segmentation in CT sequences.

Computer object segmentation by nonlinear image enhancement, multidimensional clustering, and geometrically constrained contour optimization

NASA Astrophysics Data System (ADS)

Bruynooghe, Michel M.

1998-04-01

In this paper, we present a robust method for automatic object detection and delineation in noisy complex images. The proposed procedure is a three stage process that integrates image segmentation by multidimensional pixel clustering and geometrically constrained optimization of deformable contours. The first step is to enhance the original image by nonlinear unsharp masking. The second step is to segment the enhanced image by multidimensional pixel clustering, using our reducible neighborhoods clustering algorithm that has a very interesting theoretical maximal complexity. Then, candidate objects are extracted and initially delineated by an optimized region merging algorithm, that is based on ascendant hierarchical clustering with contiguity constraints and on the maximization of average contour gradients. The third step is to optimize the delineation of previously extracted and initially delineated objects. Deformable object contours have been modeled by cubic splines. An affine invariant has been used to control the undesired formation of cusps and loops. Non linear constrained optimization has been used to maximize the external energy. This avoids the difficult and non reproducible choice of regularization parameters, that are required by classical snake models. The proposed method has been applied successfully to the detection of fine and subtle microcalcifications in X-ray mammographic images, to defect detection by moire image analysis, and to the analysis of microrugosities of thin metallic films. The later implementation of the proposed method on a digital signal processor associated to a vector coprocessor would allow the design of a real-time object detection and delineation system for applications in medical imaging and in industrial computer vision.

Neighborhood Attributes Associated With the Social Environment.

PubMed

Child, Stephanie T; Schoffman, Danielle E; Kaczynski, Andrew T; Forthofer, Melinda; Wilcox, Sara; Baruth, Meghan

2016-11-01

To examine the association between specific attributes of neighborhood environments and four social environment measures. Data were collected as part of a baseline survey among participants enrolling in a walking intervention. Participants were recruited from a metropolitan area in a Southeastern state. Participants (n = 294) were predominantly African-American (67%) and female (86%), with some college education (79%) and a mean age of 49. The International Physical Activity Questionnaire Environment Module assessed perceptions about neighborhood attributes. The social environment was assessed using three distinct scales: social cohesion, social interactions with neighbors, and social support for physical activity from family and friends. Multiple regression models examined associations between neighborhood attributes and social environment measures, adjusting for demographic variables. Having walkable destinations and having access to amenities and transit stops were associated with increased interactions with neighbors (b = 1.32, 1.04, and 1.68, respectively, p < .05). Attributes related to structural support for physical activity (sidewalks, street connectivity, recreation facilities) were associated with increased interactions with neighbors (b = 1.47, 1.34, and 1.13, respectively, p < .05). Bicycling facilities that were maintained (i.e., bike lanes, racks) were associated with social support for physical activity from family and friends (b = .43 and .30, respectively, p < .05). The study highlights key attributes of neighborhood environments that may be associated with the social context of such settings. © 2016 by American Journal of Health Promotion, Inc.

Is Your Neighborhood Designed to Support Physical Activity? A Brief Streetscape Audit Tool.

PubMed

Sallis, James F; Cain, Kelli L; Conway, Terry L; Gavand, Kavita A; Millstein, Rachel A; Geremia, Carrie M; Frank, Lawrence D; Saelens, Brian E; Glanz, Karen; King, Abby C

2015-09-03

Macro level built environment factors (eg, street connectivity, walkability) are correlated with physical activity. Less studied but more modifiable microscale elements of the environment (eg, crosswalks) may also affect physical activity, but short audit measures of microscale elements are needed to promote wider use. This study evaluated the relation of a 15-item neighborhood environment audit tool with a full version of the tool to assess neighborhood design on physical activity in 4 age groups. From the 120-item Microscale Audit of Pedestrian Streetscapes (MAPS) measure of street design, sidewalks, and street crossings, we developed the 15-item version (MAPS-Mini) on the basis of associations with physical activity and attribute modifiability. As a sample of a likely walking route, MAPS-Mini was conducted on a 0.25-mile route from participant residences toward the nearest nonresidential destination for children (n = 758), adolescents (n = 897), younger adults (n = 1,655), and older adults (n = 367). Active transportation and leisure physical activity were measured with age-appropriate surveys, and accelerometers provided objective physical activity measures. Mixed-model regressions were conducted for each MAPS item and a total environment score, adjusted for demographics, participant clustering, and macrolevel walkability. Total scores of MAPS-Mini and the 120-item MAPS correlated at r = .85. Total microscale environment scores were significantly related to active transportation in all age groups. Items related to active transport in 3 age groups were presence of sidewalks, curb cuts, street lights, benches, and buffer between street and sidewalk. The total score was related to leisure physical activity and accelerometer measures only in children. The MAPS-Mini environment measure is short enough to be practical for use by community groups and planning agencies and is a valid substitute for the full version that is 8 times longer.

Projection moire for remote contour analysis

NASA Technical Reports Server (NTRS)

Doty, J. L.

1983-01-01

Remote projection and viewing of moire contours are examined analytically for a system employing separate projection and viewing optics, with specific attention paid to the practical limitations imposed by the optical systems. It is found that planar contours are possible only when the optics are telecentric (exit pupil at infinity) but that the requirement for spatial separability of the contour fringes from extraneous fringes is independent of the specific optics and is a function only of the angle separating the two optic axes. In the nontelecentric case, the contour separation near the object is unchanged from that of the telecentric case, although the contours are distorted into low-eccentricity (near-circular) ellipses. Furthermore, the minimum contour spacing is directly related to the depth of focus through the resolution of the optics.

Perceptions of prominent neighborhood individuals regarding neighborhood factors and intimate partner violence.

PubMed

Yonas, Michael; Akers, Aletha Y; Burke, Jessica G; Chang, Judy C; Thomas, Alicia L; Thomas, Aletha L; O'Campo, Patricia

2011-04-01

Research addressing the impact of neighborhood factors on intimate partner violence (IPV) often lacks discussion of how and why such factors impact IPV. In order to address this gap, 16 prominent neighborhood individuals (PNI) from 4 low-income urban neighborhoods were asked to share through in-depth interviews their insights and perceptions of IPV as an issue in their neighborhoods, and the relationship between social and structural neighborhood-level factors and IPV. PNIs most often associated IPV with only physical violence. Several did not feel IPV was a significant issue in their neighborhood, confirming a lack of awareness and underreporting of IPV. However, other PNIs were able to speak of the relationship between IPV and neighborhood factors, including lack of opportunities for employment, vacant housing, trash management, lack of community awareness, and social capacity to act to address IPV. Results provide unique insights regarding the mechanisms linking neighborhood factors to IPV outcomes. These results contribute to a deeper understanding of contextual influences upon IPV, the development of tailored quantitative research and to the design of local multi-level public health IPV intervention and prevention efforts.

NEIGHBORHOOD NORMS AND SUBSTANCE USE AMONG TEENS

PubMed Central

Musick, Kelly; Seltzer, Judith A.; Schwartz, Christine R.

2008-01-01

This paper uses new data from the Los Angeles Family and Neighborhood Survey (L.A. FANS) to examine how neighborhood norms shape teenagers’ substance use. Specifically, it takes advantage of clustered data at the neighborhood level to relate adult neighbors’ attitudes and behavior with respect to smoking, drinking, and drugs, which we treat as norms, to teenagers’ own smoking, drinking, and drug use. We use hierarchical linear models to account for parents’ attitudes and behavior and other characteristics of individuals and families. We also investigate how the association between neighborhood norms and teen behavior depends on: (1) the strength of norms, as measured by consensus in neighbors’ attitudes and conformity in their behavior; (2) the willingness and ability of neighbors to enforce norms, for instance, by monitoring teens’ activities; and (3) the degree to which teens are exposed to their neighbors. We find little association between neighborhood norms and teen substance use, regardless of how we condition the relationship. We discuss possible theoretical and methodological explanations for this finding. PMID:18496598

Augmenting atlas-based liver segmentation for radiotherapy treatment planning by incorporating image features proximal to the atlas contours

NASA Astrophysics Data System (ADS)

Li, Dengwang; Liu, Li; Chen, Jinhu; Li, Hongsheng; Yin, Yong; Ibragimov, Bulat; Xing, Lei

2017-01-01

Atlas-based segmentation utilizes a library of previously delineated contours of similar cases to facilitate automatic segmentation. The problem, however, remains challenging because of limited information carried by the contours in the library. In this studying, we developed a narrow-shell strategy to enhance the information of each contour in the library and to improve the accuracy of the exiting atlas-based approach. This study presented a new concept of atlas based segmentation method. Instead of using the complete volume of the target organs, only information along the organ contours from the atlas images was used for guiding segmentation of the new image. In setting up an atlas-based library, we included not only the coordinates of contour points, but also the image features adjacent to the contour. In this work, 139 CT images with normal appearing livers collected for radiotherapy treatment planning were used to construct the library. The CT images within the library were first registered to each other using affine registration. The nonlinear narrow shell was generated alongside the object contours of registered images. Matching voxels were selected inside common narrow shell image features of a library case and a new case using a speed-up robust features (SURF) strategy. A deformable registration was then performed using a thin plate splines (TPS) technique. The contour associated with the library case was propagated automatically onto the new image by exploiting the deformation field vectors. The liver contour was finally obtained by employing level set based energy optimization within the narrow shell. The performance of the proposed method was evaluated by comparing quantitatively the auto-segmentation results with that delineated by physicians. A novel atlas-based segmentation technique with inclusion of neighborhood image features through the introduction of a narrow-shell surrounding the target objects was established. Application of the technique to

Augmenting atlas-based liver segmentation for radiotherapy treatment planning by incorporating image features proximal to the atlas contours.

PubMed

Li, Dengwang; Liu, Li; Chen, Jinhu; Li, Hongsheng; Yin, Yong; Ibragimov, Bulat; Xing, Lei

2017-01-07

Atlas-based segmentation utilizes a library of previously delineated contours of similar cases to facilitate automatic segmentation. The problem, however, remains challenging because of limited information carried by the contours in the library. In this studying, we developed a narrow-shell strategy to enhance the information of each contour in the library and to improve the accuracy of the exiting atlas-based approach. This study presented a new concept of atlas based segmentation method. Instead of using the complete volume of the target organs, only information along the organ contours from the atlas images was used for guiding segmentation of the new image. In setting up an atlas-based library, we included not only the coordinates of contour points, but also the image features adjacent to the contour. In this work, 139 CT images with normal appearing livers collected for radiotherapy treatment planning were used to construct the library. The CT images within the library were first registered to each other using affine registration. The nonlinear narrow shell was generated alongside the object contours of registered images. Matching voxels were selected inside common narrow shell image features of a library case and a new case using a speed-up robust features (SURF) strategy. A deformable registration was then performed using a thin plate splines (TPS) technique. The contour associated with the library case was propagated automatically onto the new image by exploiting the deformation field vectors. The liver contour was finally obtained by employing level set based energy optimization within the narrow shell. The performance of the proposed method was evaluated by comparing quantitatively the auto-segmentation results with that delineated by physicians. A novel atlas-based segmentation technique with inclusion of neighborhood image features through the introduction of a narrow-shell surrounding the target objects was established. Application of the technique to

Perceived and Objective Measures of Neighborhood Walkability and Physical Activity among Adults in Japan: A Multilevel Analysis of a Nationally Representative Sample

PubMed Central

Hanibuchi, Tomoya; Nakaya, Tomoki; Yonejima, Mayuko; Honjo, Kaori

2015-01-01

Although associations between a person’s neighborhood and their health have been studied internationally, most studies have been limited to a few cities or towns. Therefore, we used a nationally representative sample to explore whether perceived and objective neighborhood walkability was associated with the physical activity of residents. Data were analyzed from the Japanese General Social Surveys of 2010 (n = 2395; 1114 men and 1281 women). Perceived walkability was scored using factor analysis for the respondents’ perceptions of neighborhood conditions, while objective walkability was measured using the geographic information system approach. Finally, multilevel logistic regression analysis was performed to examine whether neighborhood walkability was associated with the frequency of leisure-time physical activity (LTPA) among respondents. We found that perceived walkability was positively associated with the frequency of LTPA (odds ratio of the highest quartile was 1.53 (1.14–2.05) compared with the lowest quartile); however, objective walkability showed no association. When stratified by gender, an association between perceived walkability and LTPA was observed among women, but only a marginally significant association was present between objective walkability and LTPA among men. We conclude that the association between neighborhood walkability and LTPA can be partially generalized across Japan. PMID:26512682

Neighborhood walkability moderates the association between low back pain and physical activity: A co-twin control study.

PubMed

Zadro, J R; Shirley, D; Pinheiro, M B; Bauman, A; Duncan, G E; Ferreira, P H

2017-06-01

The aim of this study was to investigate whether neighborhood walkability moderates the association between low back pain (LBP) and physical activity (PA), using a co-twin design to control for genetics and shared environmental factors. A cross-sectional analysis was performed on 10,228 twins from the Washington State Twin Registry with available data on LBP from recruitment surveys between 2009 and 2013. LBP within the past 3months was our exposure variable. Our outcome variables were sufficient moderate or vigorous-intensity PA (MVPA, defined as at least 75min of vigorous-intensity PA, or 150min of moderate-intensity PA per week), and walking (≥150min per week). Neighborhood walkability, estimated using the commercially available Walk Score®, was our moderator variable. After controlling for the influence of genetics and shared environment, individuals reporting LBP were significantly less likely to engage in sufficient MVPA if they lived in a neighborhood with high walkability (OR=0.59, 95%CI: 0.36-0.96). There was no association between LBP and sufficient MVPA for individuals living in a neighborhood with low walkability (OR=1.27, 95%CI: 0.93-1.72), demonstrating that walkability is a significant moderator of the association between LBP and PA (interaction p=0.013). These findings were similar for the association between LBP and walking (high walkability OR=0.42, 95%CI: 0.22-0.78; low walkability OR=0.71, 95%CI: 0.46-1.12), although the interaction was not significant (p=0.700). Neighborhood walkability moderates the association between LBP and PA. Our results highlight the importance of targeting interventions promoting PA towards individuals with LBP living in a neighborhood with good walkable access to amenities. Copyright © 2017 Elsevier Inc. All rights reserved.

Preserving Neighborhood Opportunity: Where Federal Housing Subsidies Expire

PubMed Central

Lens, Michael C.; Reina, Vincent

2017-01-01

Rent burdens are increasing in U.S. metropolitan areas while subsidies on privately owned, publicly subsidized rental units are expiring. As a result, some of the few remaining affordable units in opportunity neighborhoods are at risk of being converted to market rate. Policy makers face a decision about whether to devote their efforts and scarce resources toward developing new affordable housing, recapitalizing existing subsidized housing, and/or preserving properties with expiring subsidies. There are several reasons to preserve these subsidies, one being that properties may be located in neighborhoods with greater opportunity. In this article, we use several sources of data at the census tract level to learn how subsidy expirations affect neighborhood opportunity for low-income households. Our analysis presents several key findings. First, we find that units that left the project-based Section 8 program were – on average – in lower opportunity neighborhoods, but these neighborhoods were improving. In addition, properties due to expiry from the Section 8 program between 2011 and 2020 are in higher opportunity neighborhoods than any other subsidy program. On the contrary, new Low-Income Housing Tax Credit (LIHTC) units were developed in tracts similar to those where LIHTC units are currently active, which tend to be lower opportunity neighborhoods. PMID:28553063

Preserving Neighborhood Opportunity: Where Federal Housing Subsidies Expire.

PubMed

Lens, Michael C; Reina, Vincent

2016-01-01

Rent burdens are increasing in U.S. metropolitan areas while subsidies on privately owned, publicly subsidized rental units are expiring. As a result, some of the few remaining affordable units in opportunity neighborhoods are at risk of being converted to market rate. Policy makers face a decision about whether to devote their efforts and scarce resources toward developing new affordable housing, recapitalizing existing subsidized housing, and/or preserving properties with expiring subsidies. There are several reasons to preserve these subsidies, one being that properties may be located in neighborhoods with greater opportunity. In this article, we use several sources of data at the census tract level to learn how subsidy expirations affect neighborhood opportunity for low-income households. Our analysis presents several key findings. First, we find that units that left the project-based Section 8 program were - on average - in lower opportunity neighborhoods, but these neighborhoods were improving. In addition, properties due to expiry from the Section 8 program between 2011 and 2020 are in higher opportunity neighborhoods than any other subsidy program. On the contrary, new Low-Income Housing Tax Credit (LIHTC) units were developed in tracts similar to those where LIHTC units are currently active, which tend to be lower opportunity neighborhoods.

ADOLESCENTS’ EXPOSURE TO COMMUNITY VIOLENCE: ARE NEIGHBORHOOD YOUTH ORGANIZATIONS PROTECTIVE?

PubMed Central

Gardner, Margo; Brooks-Gunn, Jeanne

2011-01-01

Using data from the Project on Human Development in Chicago Neighborhoods (PHDCN), we identified a significant inverse association between the variety of youth organizations available at the neighborhood level and adolescents’ exposure to community violence. We examined two non-competing explanations for this finding. First, at the individual level, we tested the hypothesis that access to a greater variety of neighborhood youth organizations predicts adolescents’ participation in organized community-based activities, which, in turn, protects against community violence exposure. Second, at the neighborhood level, we tested the hypothesis that lower violent crime rates explain the inverse relation between neighborhood youth organization variety and community violence exposure. Our findings supported the latter of these two mechanisms. PMID:21666761

ADOLESCENTS' EXPOSURE TO COMMUNITY VIOLENCE: ARE NEIGHBORHOOD YOUTH ORGANIZATIONS PROTECTIVE?

PubMed

Gardner, Margo; Brooks-Gunn, Jeanne

2009-05-01

Using data from the Project on Human Development in Chicago Neighborhoods (PHDCN), we identified a significant inverse association between the variety of youth organizations available at the neighborhood level and adolescents' exposure to community violence. We examined two non-competing explanations for this finding. First, at the individual level, we tested the hypothesis that access to a greater variety of neighborhood youth organizations predicts adolescents' participation in organized community-based activities, which, in turn, protects against community violence exposure. Second, at the neighborhood level, we tested the hypothesis that lower violent crime rates explain the inverse relation between neighborhood youth organization variety and community violence exposure. Our findings supported the latter of these two mechanisms.

Intra-retinal segmentation of optical coherence tomography images using active contours with a dynamic programming initialization and an adaptive weighting strategy

NASA Astrophysics Data System (ADS)

Gholami, Peyman; Roy, Priyanka; Kuppuswamy Parthasarathy, Mohana; Ommani, Abbas; Zelek, John; Lakshminarayanan, Vasudevan

2018-02-01

Retinal layer shape and thickness are one of the main indicators in the diagnosis of ocular diseases. We present an active contour approach to localize intra-retinal boundaries of eight retinal layers from OCT images. The initial locations of the active contour curves are determined using a Viterbi dynamic programming method. The main energy function is a Chan-Vese active contour model without edges. A boundary term is added to the energy function using an adaptive weighting method to help curves converge to the retinal layer edges more precisely, after evolving of curves towards boundaries, in final iterations. A wavelet-based denoising method is used to remove speckle from OCT images while preserving important details and edges. The performance of the proposed method was tested on a set of healthy and diseased eye SD-OCT images. The experimental results, compared between the proposed method and the manual segmentation, which was determined by an optometrist, indicate that our method has obtained an average of 95.29%, 92.78%, 95.86%, 87.93%, 82.67%, and 90.25% respectively, for accuracy, sensitivity, specificity, precision, Jaccard Index, and Dice Similarity Coefficient over all segmented layers. These results justify the robustness of the proposed method in determining the location of different retinal layers.

The Development of Skull Prosthesis Through Active Contour Model.

PubMed

Chen, Yi-Wen; Shih, Cheng-Ting; Cheng, Chen-Yang; Lin, Yu-Cheng

2017-09-09

Skull defects result in brain infection and inadequate brain protection and pose a general danger to patient health. To avoid these situations and prevent re-injury, a prosthesis must be constructed and grafted onto the deficient region. With the development of rapid customization through additive manufacturing and 3D printing technology, skull prostheses can be fabricated accurately and efficiently prior to cranioplasty. However, an unfitted skull prosthesis made with a metal implant can cause repeated infection, potentially necessitating secondary surgery. This paper presents a method of creating suitably geometric graphics of skull defects to be applied in skull repair through active contour models. These models can be adjusted in each computed tomography slice according to the graphic features, and the curves representing the skull defect can be modeled. The generated graphics can adequately mimic the natural curvature of the complete skull. This method will enable clinical surgeons to rapidly implant customized prostheses, which is of particular importance in emergency surgery. The findings of this research can help surgeons provide patients with skull defects with treatment of the highest quality.

3D Filament Network Segmentation with Multiple Active Contours

NASA Astrophysics Data System (ADS)

Xu, Ting; Vavylonis, Dimitrios; Huang, Xiaolei

2014-03-01

Fluorescence microscopy is frequently used to study two and three dimensional network structures formed by cytoskeletal polymer fibers such as actin filaments and microtubules. While these cytoskeletal structures are often dilute enough to allow imaging of individual filaments or bundles of them, quantitative analysis of these images is challenging. To facilitate quantitative, reproducible and objective analysis of the image data, we developed a semi-automated method to extract actin networks and retrieve their topology in 3D. Our method uses multiple Stretching Open Active Contours (SOACs) that are automatically initialized at image intensity ridges and then evolve along the centerlines of filaments in the network. SOACs can merge, stop at junctions, and reconfigure with others to allow smooth crossing at junctions of filaments. The proposed approach is generally applicable to images of curvilinear networks with low SNR. We demonstrate its potential by extracting the centerlines of synthetic meshwork images, actin networks in 2D TIRF Microscopy images, and 3D actin cable meshworks of live fission yeast cells imaged by spinning disk confocal microscopy.

Gray matter segmentation of the spinal cord with active contours in MR images.

PubMed

Datta, Esha; Papinutto, Nico; Schlaeger, Regina; Zhu, Alyssa; Carballido-Gamio, Julio; Henry, Roland G

2017-02-15

Fully or partially automated spinal cord gray matter segmentation techniques for spinal cord gray matter segmentation will allow for pivotal spinal cord gray matter measurements in the study of various neurological disorders. The objective of this work was multi-fold: (1) to develop a gray matter segmentation technique that uses registration methods with an existing delineation of the cord edge along with Morphological Geodesic Active Contour (MGAC) models; (2) to assess the accuracy and reproducibility of the newly developed technique on 2D PSIR T1 weighted images; (3) to test how the algorithm performs on different resolutions and other contrasts; (4) to demonstrate how the algorithm can be extended to 3D scans; and (5) to show the clinical potential for multiple sclerosis patients. The MGAC algorithm was developed using a publicly available implementation of a morphological geodesic active contour model and the spinal cord segmentation tool of the software Jim (Xinapse Systems) for initial estimate of the cord boundary. The MGAC algorithm was demonstrated on 2D PSIR images of the C2/C3 level with two different resolutions, 2D T2* weighted images of the C2/C3 level, and a 3D PSIR image. These images were acquired from 45 healthy controls and 58 multiple sclerosis patients selected for the absence of evident lesions at the C2/C3 level. Accuracy was assessed though visual assessment, Hausdorff distances, and Dice similarity coefficients. Reproducibility was assessed through interclass correlation coefficients. Validity was assessed through comparison of segmented gray matter areas in images with different resolution for both manual and MGAC segmentations. Between MGAC and manual segmentations in healthy controls, the mean Dice similarity coefficient was 0.88 (0.82-0.93) and the mean Hausdorff distance was 0.61 (0.46-0.76) mm. The interclass correlation coefficient from test and retest scans of healthy controls was 0.88. The percent change between the manual

Neighborhood educational disparities in active commuting among women: the effect of distance between the place of residence and the place of work/study (an ACTI-Cités study).

PubMed

Perchoux, Camille; Nazare, Julie-Anne; Benmarhnia, Tarik; Salze, Paul; Feuillet, Thierry; Hercberg, Serge; Hess, Franck; Menai, Mehdi; Weber, Christiane; Charreire, Hélène; Enaux, Christophe; Oppert, Jean-Michel; Simon, Chantal

2017-06-12

Active transportation has been associated with favorable health outcomes. Previous research highlighted the influence of neighborhood educational level on active transportation. However, little is known regarding the effect of commuting distance on social disparities in active commuting. In this regard, women have been poorly studied. The objective of this paper was to evaluate the relationship between neighborhood educational level and active commuting, and to assess whether the commuting distance modifies this relationship in adult women. This cross-sectional study is based on a subsample of women from the Nutrinet-Santé web-cohort (N = 1169). Binomial, log-binomial and negative binomial regressions were used to assess the associations between neighborhood education level and (i) the likelihood of reporting any active commuting time, and (ii) the share of commuting time made by active transportation modes. Potential effect measure modification of distance to work on the previous associations was assessed both on the additive and the multiplicative scales. Neighborhood education level was positively associated with the probability of reporting any active commuting time (relative risk = 1.774; p < 0.05) and the share of commuting time spent active (relative risk = 1.423; p < 0.05). The impact of neighborhood education was greater at long distances to work for both outcomes. Our results suggest that neighborhood educational disparities in active commuting tend to increase with commuting distance among women. Further research is needed to provide geographically driven guidance for health promotion intervention aiming at reducing disparities in active transportation among socioeconomic groups.

An improved spatial contour tree constructed method

NASA Astrophysics Data System (ADS)

Zheng, Yi; Zhang, Ling; Guilbert, Eric; Long, Yi

2018-05-01

Contours are important data to delineate the landform on a map. A contour tree provides an object-oriented description of landforms and can be used to enrich the topological information. The traditional contour tree is used to store topological relationships between contours in a hierarchical structure and allows for the identification of eminences and depressions as sets of nested contours. This research proposes an improved contour tree so-called spatial contour tree that contains not only the topological but also the geometric information. It can be regarded as a terrain skeleton in 3-dimention, and it is established based on the spatial nodes of contours which have the latitude, longitude and elevation information. The spatial contour tree is built by connecting spatial nodes from low to high elevation for a positive landform, and from high to low elevation for a negative landform to form a hierarchical structure. The connection between two spatial nodes can provide the real distance and direction as a Euclidean vector in 3-dimention. In this paper, the construction method is tested in the experiment, and the results are discussed. The proposed hierarchical structure is in 3-demintion and can show the skeleton inside a terrain. The structure, where all nodes have geo-information, can be used to distinguish different landforms and applied for contour generalization with consideration of geographic characteristics.

Understanding Neighborhood Environment Related to Hong Kong Children’s Physical Activity: A Qualitative Study Using Nominal Group Technique

PubMed Central

He, Gang; Cerin, Ester; Huang, Wendy Y.; Wong, Stephen H.

2014-01-01

Background Relationships between the neighborhood environment and children’s physical activity have been well documented in Western countries but are less investigated in ultra-dense Asian cities. The aim of this study was to identify the environmental facilitators and barriers of physical activity behaviors among Hong Kong Chinese children using nominal group technique. Methods Five nominal groups were conducted among 34 children aged 10–11 years from four types of neighborhoods varying in socio-economic status and walkability in Hong Kong. Environmental factors were generated by children in response to the question “What neighborhood environments do you think would increase or decrease your willingness to do physical activity?” Factors were prioritized in order of their importance to children’s physical activity. Results Sixteen unique environmental factors, which were perceived as the most important to children’s physical activity, were identified. Factors perceived as physical activity-facilitators included “Sufficient lighting”, “Bridge or tunnel”, “Few cars on roads”, “Convenient transportation”, “Subway station”, “Recreation grounds”, “Shopping malls with air conditioning”, “Fresh air”, “Interesting animals”, and “Perfume shop”. Factors perceived as physical activity-barriers included “People who make me feel unsafe”, “Crimes nearby”, “Afraid of being taken or hurt at night”, “Hard to find toilet in shopping mall”, “Too much noise”, and “Too many people in recreation grounds”. Conclusions Specific physical activity-related environmental facilitators and barriers, which are unique in an ultra-dense city, were identified by Hong Kong children. These initial findings can inform future examinations of the physical activity-environment relationship among children in Hong Kong and similar Asian cities. PMID:25187960

The Effect of Neighborhood Recorded Crime on Fear: Does Neighborhood Social Context Matter?

PubMed

Pearson, Amber L; Breetzke, Gregory; Ivory, Vivienne

2015-09-01

A number of individual and neighborhood-level factors may influence the relationship between recorded crime in one's neighborhood and fear of crime. Understanding these factors may assist in reducing fear, which has been associated with poorer physical and mental health. The aim of this study was to evaluate whether the effect of recorded crime rates on fear differs based on the neighborhood social context (social fragmentation) using hierarchical regression modelling, with separate analyses by crime type. Recorded crimes (2008-2010) and national (New Zealand) survey data were used. Higher crime in a neighborhood was associated with higher fear of crime, with only small effect size differences in feelings of fear by recorded type of crime. However, when stratified, the associations between violent and drug/alcohol crimes and fear of crime were larger for those living in highly fragmented neighborhoods compared with less fragmented neighborhoods. Efforts to alleviate fear of crime should focus on the broader neighborhood social context in which these feelings are espoused.

Anatomical contouring variability in thoracic organs at risk

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

McCall, Ross, E-mail: rmccall86@gmail.com; MacLennan, Grayden; Taylor, Matthew

2016-01-01

The purpose of this study was to determine whether contouring thoracic organs at risk was consistent among medical dosimetrists and to identify how trends in dosimetrist's education and experience affected contouring accuracy. Qualitative and quantitative methods were used to contextualize the raw data that were obtained. A total of 3 different computed tomography (CT) data sets were provided to medical dosimetrists (N = 13) across 5 different institutions. The medical dosimetrists were directed to contour the lungs, heart, spinal cord, and esophagus. The medical dosimetrists were instructed to contour in line with their institutional standards and were allowed to usemore » any contouring tool or technique that they would traditionally use. The contours from each medical dosimetrist were evaluated against “gold standard” contours drawn and validated by 2 radiation oncology physicians. The dosimetrist-derived contours were evaluated against the gold standard using both a Dice coefficient method and a penalty-based metric scoring system. A short survey was also completed by each medical dosimetrist to evaluate their individual contouring experience. There was no significant variation in the contouring consistency of the lungs and spinal cord. Intradosimetrist contouring was consistent for those who contoured the esophagus and heart correctly; however, medical dosimetrists with a poor metric score showed erratic and inconsistent methods of contouring.« less

Radiographic and anatomic basis for prostate contouring errors and methods to improve prostate contouring accuracy.

PubMed

McLaughlin, Patrick W; Evans, Cheryl; Feng, Mary; Narayana, Vrinda

2010-02-01

Use of highly conformal radiation for prostate cancer can lead to both overtreatment of surrounding normal tissues and undertreatment of the prostate itself. In this retrospective study we analyzed the radiographic and anatomic basis of common errors in computed tomography (CT) contouring and suggest methods to correct them. Three hundred patients with prostate cancer underwent CT and magnetic resonance imaging (MRI). The prostate was delineated independently on the data sets. CT and MRI contours were compared by use of deformable registration. Errors in target delineation were analyzed and methods to avoid such errors detailed. Contouring errors were identified at the prostatic apex, mid gland, and base on CT. At the apex, the genitourinary diaphragm, rectum, and anterior fascia contribute to overestimation. At the mid prostate, the anterior and lateral fasciae contribute to overestimation. At the base, the bladder and anterior fascia contribute to anterior overestimation. Transition zone hypertrophy and bladder neck variability contribute to errors of overestimation and underestimation at the superior base, whereas variable prostate-to-seminal vesicle relationships with prostate hypertrophy contribute to contouring errors at the posterior base. Most CT contouring errors can be detected by (1) inspection of a lateral view of prostate contours to detect projection from the expected globular form and (2) recognition of anatomic structures (genitourinary diaphragm) on the CT scans that are clearly visible on MRI. This study shows that many CT prostate contouring errors can be improved without direct incorporation of MRI data. Copyright 2010 Elsevier Inc. All rights reserved.

Automated tumour boundary delineation on 18F-FDG PET images using active contour coupled with shifted-optimal thresholding method

NASA Astrophysics Data System (ADS)

Khamwan, Kitiwat; Krisanachinda, Anchali; Pluempitiwiriyawej, Charnchai

2012-10-01

This study presents an automatic method to trace the boundary of the tumour in positron emission tomography (PET) images. It has been discovered that Otsu's threshold value is biased when the within-class variances between the object and the background are significantly different. To solve the problem, a double-stage threshold search that minimizes the energy between the first Otsu's threshold and the maximum intensity value is introduced. Such shifted-optimal thresholding is embedded into a region-based active contour so that both algorithms are performed consecutively. The efficiency of the method is validated using six sphere inserts (0.52-26.53 cc volume) of the IEC/2001 torso phantom. Both spheres and phantom were filled with 18F solution with four source-to-background ratio (SBR) measurements of PET images. The results illustrate that the tumour volumes segmented by combined algorithm are of higher accuracy than the traditional active contour. The method had been clinically implemented in ten oesophageal cancer patients. The results are evaluated and compared with the manual tracing by an experienced radiation oncologist. The advantage of the algorithm is the reduced erroneous delineation that improves the precision and accuracy of PET tumour contouring. Moreover, the combined method is robust, independent of the SBR threshold-volume curves, and it does not require prior lesion size measurement.

The Physiological Expression of Living in Disadvantaged Neighborhoods for Youth

PubMed Central

Brenner, Allison B.; Zimmerman, Marc A.; Bauermeister, Jose A.; Caldwell, Cleopatra H.

2012-01-01

Evidence suggests that the consequences of chronic exposure to stressors extend beyond psychological effects, and that adolescents living in socio-economically disadvantaged neighborhoods may experience an accumulation of exposure to stressors that wears down the physical systems in the body, resulting in hyper-activation of the stress response. This research examines the relationship between exposure to neighborhood stressors and salivary cortisol reactivity in a sample of 163 at-risk African American adolescents (average age 21; 50% female) living in disadvantaged urban neighborhoods. More specifically, the relationship between neighborhood stressors and physiological stress, measured by baseline cortisol and cortisol reactivity is assessed. This research also examines several moderating pathways between exposure to neighborhood disadvantage and cortisol reactivity including substance use, high effort coping, psychological stress and social support. Results indicate that both individual and neighborhood-level factors influence adolescent cortisol. High effort coping and psychological stress were associated with cortisol in the sample, and exposure to neighborhood socio-economic disadvantage resulted in an atypical cortisol response. In addition, neighborhood disadvantage interacted with intra- and interpersonal factors to affect cortisol indirectly. Thus, living in disadvantaged neighborhoods may take a psychological and physiological toll on adolescents, and it also may exert synergistic effects through individual coping and vulnerabilities. PMID:23086016

Semantic shape similarity-based contour tracking evaluation

NASA Astrophysics Data System (ADS)

Zhang, Xiaoqin; Luo, Wenhan; Zhao, Li; Li, Wei; Hu, Weiming

2011-10-01

One major problem of contour-based tracking is how to evaluate the accuracy of tracking results due to nonrigid and deformative properties of contours. We propose a shape context-based evaluation measure that considers the semantic shape similarity between the tracked contour and ground-truth contour. In addition, a pyramid match kernel is introduced for shape histogram matching, which can effectively deal with the contours with different scales. Experimental results demonstrate, compared to two start-of-art evaluation measures, our measure effectively captures the local shape information and thus is more consistent with human vision.

Isolating contour information from arbitrary images

NASA Technical Reports Server (NTRS)

Jobson, Daniel J.

1989-01-01

Aspects of natural vision (physiological and perceptual) serve as a basis for attempting the development of a general processing scheme for contour extraction. Contour information is assumed to be central to visual recognition skills. While the scheme must be regarded as highly preliminary, initial results do compare favorably with the visual perception of structure. The scheme pays special attention to the construction of a smallest scale circular difference-of-Gaussian (DOG) convolution, calibration of multiscale edge detection thresholds with the visual perception of grayscale boundaries, and contour/texture discrimination methods derived from fundamental assumptions of connectivity and the characteristics of printed text. Contour information is required to fall between a minimum connectivity limit and maximum regional spatial density limit at each scale. Results support the idea that contour information, in images possessing good image quality, is (centered at about 10 cyc/deg and 30 cyc/deg). Further, lower spatial frequency channels appear to play a major role only in contour extraction from images with serious global image defects.

Orientation-crowding within contours.

PubMed

Glen, James C; Dakin, Steven C

2013-07-15

We examined how crowding (the breakdown of object recognition in the periphery caused by interference from "clutter") depends on the global arrangement of target and distracting flanker elements. Specifically we probed orientation discrimination using a near-vertical target Gabor flanked by two vertical distractor Gabors (one above and one below the target). By applying variable (opposite-sign) horizontal offsets to the positions of the two flankers we arranged the elements so that on some trials they formed contours with the target and on others they did not. While the presence of flankers generally elevated orientation discrimination thresholds for the target we observe maximal crowding not when flanker and targets were co-aligned but when a small spatial offset was applied to flanker location, so that contours formed between flanker and targets only when the target orientation was cued. We also report that observers' orientation judgments are biased, with target orientation appearing either attracted or repulsed by the global/contour orientation. A second experiment reveals that the sign of this effect is dependent both on observer and on eccentricity. In general, the magnitude of repulsion is reduced with eccentricity but whether this becomes attraction (of element orientation to contour orientation) is dependent on observer. We note however that across observers and eccentricities, the magnitude of repulsion correlates positively with the amount of release from crowding observed with co-aligned targets and flankers, supporting the notion of fluctuating bias as the basis for elevated crowding within contours.

Neighborhoods as a Power Factor.

ERIC Educational Resources Information Center

Woody, Bette; And Others

1980-01-01

Examines Washington, DC, Advisory Neighborhood Commissions (ANC) as an illustration of neighborhood involvement in city revitalization and maintenance. Considers (1) hypotheses about neighborhood roles and participation in public issue raising; (2) ANC structure, participation, and decision roles; and (3) likely roles neighborhood governments can…

Neighborhood, Family, and Work: Influences on the Premarital Behaviors of Adolescent Males.

ERIC Educational Resources Information Center

Ku, Leighton; And Others

1993-01-01

Analysis of national survey data suggests that level of sexual activity and likelihood of paternity among adolescent males are related to personal financial resources and employment but also to neighborhood unemployment. Discusses associations of sexual activity, contraceptive use, and paternity with personal and neighborhood race/ethnicity,…

Reclaiming streets for outdoor play: A process and impact evaluation of "Juega en tu Barrio" (Play in your Neighborhood), an intervention to increase physical activity and opportunities for play.

PubMed

Cortinez-O'Ryan, Andrea; Albagli, Andrea; Sadarangani, Kabir P; Aguilar-Farias, Nicolas

2017-01-01

New strategies are required to create supportive physical and social environments for children and promote active free-play. Juega en tu Barrio (JETB; Play in your Neighborhood) was designed and implemented to explore the effectiveness of closing a street in a low-to-middle income neighborhood in order to increase children's outside play and physical activity. A pretest-posttest design with control group was employed to investigate the intervention effects in a subsample of 100 children, 51 from the intervention neighborhood and 49 from the control neighborhood. The children wore pedometers for one week, and their parents completed questionnaires at two time points: before the intervention began and during the last two weeks of the intervention. JETB was conducted in the intervention neighborhood from 17:30 to 20:30, twice a week, from September to December 2014. Stewards ensured that the children were safe. Children and adults were assessed using systematic observation. The intervention and control neighborhoods included 177 and 116 children respectively. The average attendance per event was 60 children (SD = 22, reach 34%). In the intervention neighborhood, a significant increase between baseline and final assessment was observed in after-school outdoor playtime (p = 0.02), steps during the 3-hour intervention (p = 0.004), and daily steps Monday to Sunday (p = 0.006). Meanwhile, no changes were observed in the control neighborhood for the same variables. The proportion of children who met recommended daily step counts increased from 27.5% to 53.0% in the intervention neighborhood (p = 0.007), while for control neighborhood no difference was observed (49.0% to 53.0% p = 0.804). JETB showed high community engagement while offering opportunities for increased outdoor play in children. The intervention showed a significant effect on the number of children meeting the daily pedometer-derived physical activity recommendations.

Do observed or perceived characteristics of the neighborhood environment mediate associations between neighborhood poverty and cumulative biological risk?

PubMed Central

Schulz, Amy J.; Mentz, Graciela; Lachance, Laurie; Zenk, Shannon N.; Johnson, Jonetta; Stokes, Carmen; Mandell, Rebecca

2013-01-01

Objective To examine contributions of observed and perceived neighborhood characteristics in explaining associations between neighborhood poverty and cumulative biological risk (CBR) in an urban community. Methods Multilevel regression analyses were conducted using cross-sectional data from a probability sample survey (n=919), and observational and census data. Dependent variable: CBR. Independent variables: Neighborhood disorder, deterioration and characteristics; perceived neighborhood social environment, physical environment, and neighborhood environment. Covariates: Neighborhood and individual demographics, health-related behaviors. Results Observed and perceived indicators of neighborhood conditions were significantly associated with CBR, after accounting for both neighborhood and individual level socioeconomic indicators. Observed and perceived neighborhood environmental conditions mediated associations between neighborhood poverty and CBR. Conclusions Findings were consistent with the hypothesis that neighborhood conditions associated with economic divestment mediate associations between neighborhood poverty and CBR. PMID:24100238

Youth Activity Involvement, Neighborhood Adult Support, Individual Decision Making Skills, and Early Adolescent Delinquent Behaviors: Testing a Conceptual Model

ERIC Educational Resources Information Center

Crean, Hugh F.

2012-01-01

This study examines a cross-sectional structural equation model of participation in youth activities, neighborhood adult support, individual decision making skills, and delinquent behavior in urban middle school youths (n = 2611). Results indicate extracurricular activity participation had both direct and indirect associations with delinquent…

Three-dimensional adult male head and skull contours.

PubMed

Lee, Calvin; Loyd, Andre M; Nightingale, Roger; Myers, Barry S; Damon, Andrew; Bass, Cameron R

2014-01-01

Traumatic brain injury (TBI) is a major public health issue, affecting millions of people annually. Anthropomorphic test devices (ATDs) and finite element models (FEMs) provide a means of understanding factors leading to TBI, potentially reducing the occurrence. Thus, there is a need to ensure that these tools accurately model humans. For example, the Hybrid III was not based on 3-dimensional human head shape data. The objective of this study is to produce average head and skull contours for an average U.S. male that can be used for ATDs and FEMs. Computed tomography (CT) scans of adult male heads were obtained from a database provided by the University of Virginia Center for Applied Biomechanics. An orthographic viewer was used to extract head and skull contours from the CT scans. Landmarks were measured graphically using HyperMesh (Altair, HyperWorks). To determine the head occipital condyle (OC) centroid, surface meshes of the OCs were made and the centroid of the surfaces was calculated. The Hybrid III contour was obtained using a MicroScribe Digitizer (Solution Technologies, Inc., Oella, MD). Comparisons of the average male and ATD contours were performed using 2 methods: (1) the midsagittal and midcoronal ATD contours relative to the OC centroid were compared to the corresponding 1 SD range of the average male contours; (2) the ATD sagittal contour was translated relative to the average male sagittal contour to minimize the area between the 2 contours. Average male head and skull contours were created. Landmark measurements were made for the dorsum sellae, nasion skin, nasion bone, infraorbital foramen, and external auditory meatus, all relative to the OC centroid. The Hybrid III midsagittal contour was outside the 1 SD range for 15.2 percent of the average male head contour but only by a maximum distance of 1.5 mm, whereas the Hybrid III midcoronal head contour was outside the 1 SD range for 12.2 percent of the average male head contour by a maximum distance

Neighborhood poverty and suicidal thoughts and attempts in late adolescence.

PubMed

Dupéré, V; Leventhal, T; Lacourse, E

2009-08-01

Suicide tends to concentrate in disadvantaged neighborhoods, and neighborhood disadvantage is associated with many important risk factors for youth suicide. However, no study has directly investigated the link between neighborhood poverty and youth suicidal behaviors, while controlling for pre-existing vulnerabilities. The objective of this study was to determine whether living in a poor neighborhood is associated with suicidal thoughts and attempts in late adolescence over and above background vulnerabilities, and whether this association can be explained by late-adolescence psychosocial risks: depression, social support, negative life events (NLEs), delinquent activities, substance abuse and exposure to suicide. The potential moderating role of neighborhood poverty was also examined. A subset of 2776 participants was selected from the Canadian National Longitudinal Survey of Children and Youth (NLSCY). Late-adolescence suicidal behaviors and risk factors were self-reported. The 2001 Canadian Census was used to characterize neighborhoods during early and middle adolescence. Late-childhood family and individual controls were assessed through parent-report. At the bivariate level, the odds of reporting suicidal thoughts were about twice as high in poor than non-poor neighborhoods, and the odds of attempting suicide were about four times higher. After controlling for background vulnerabilities, neighborhood poverty remained significantly associated with both suicidal thoughts and attempts. However, these associations were not explained by late-adolescence psychosocial risks. Rather, youth living in poor neighborhoods may be at greater risk through the amplification of other risk factors in disadvantaged neighborhoods. Potential explanations for the increased vulnerability of youth living in poor neighborhoods are discussed.

Does neighborhood social cohesion modify the relationship between neighborhood social norms and smoking behaviors in Mexico?

PubMed

Lozano, Paula; Fleischer, Nancy L; Moore, Spencer; Shigematsu, Luz Myriam Reynales; Santillán, Edna Arillo; Thrasher, James F

2016-07-01

The aim of this study was to examine the separate and combined relationships of neighborhood social norms and neighborhood social cohesion with smoking behavior in a cohort of adult Mexican smokers. Neighborhood anti-smoking norms were measured as the proportion of residents in each neighborhood who believed that society disapproves of smoking. Perceived social cohesion was measured using a 5-item cohesion scale and aggregated to the neighborhood level. Higher neighborhood anti-smoking norms were associated with less successful quitting. Neighborhood social cohesion modified the relationship between neighborhood social norms and two smoking behaviors: smoking intensity and quit attempts. Residents of neighborhoods with weaker anti-smoking norms and higher social cohesion had lower smoking intensity and more quit attempts than residents living in other areas. Social cohesion may help buffer smoking behavior in areas with weak social norms. Copyright © 2016 Elsevier Ltd. All rights reserved.

Segmenting the thoracic, abdominal and pelvic musculature on CT scans combining atlas-based model and active contour model

NASA Astrophysics Data System (ADS)

Zhang, Weidong; Liu, Jiamin; Yao, Jianhua; Summers, Ronald M.

2013-03-01

Segmentation of the musculature is very important for accurate organ segmentation, analysis of body composition, and localization of tumors in the muscle. In research fields of computer assisted surgery and computer-aided diagnosis (CAD), muscle segmentation in CT images is a necessary pre-processing step. This task is particularly challenging due to the large variability in muscle structure and the overlap in intensity between muscle and internal organs. This problem has not been solved completely, especially for all of thoracic, abdominal and pelvic regions. We propose an automated system to segment the musculature on CT scans. The method combines an atlas-based model, an active contour model and prior segmentation of fat and bones. First, body contour, fat and bones are segmented using existing methods. Second, atlas-based models are pre-defined using anatomic knowledge at multiple key positions in the body to handle the large variability in muscle shape. Third, the atlas model is refined using active contour models (ACM) that are constrained using the pre-segmented bone and fat. Before refining using ACM, the initialized atlas model of next slice is updated using previous atlas. The muscle is segmented using threshold and smoothed in 3D volume space. Thoracic, abdominal and pelvic CT scans were used to evaluate our method, and five key position slices for each case were selected and manually labeled as the reference. Compared with the reference ground truth, the overlap ratio of true positives is 91.1%+/-3.5%, and that of false positives is 5.5%+/-4.2%.

Physical activity and neighborhood resources in high school girls.

PubMed

Pate, Russell R; Colabianchi, Natalie; Porter, Dwayne; Almeida, Maria J; Lobelo, Felipe; Dowda, Marsha

2008-05-01

Physical activity behavior is influenced by a person's physical environment, but few studies have used objective measures to study the influences of the physical environment on physical activity behavior in youth. The purpose of this study was to examine the relationship between selected neighborhood physical activity resources and physical activity levels in high school girls. Participants were students in schools that had participated in a large physical activity intervention trial. The 3-Day Physical Activity Recall was completed by 1506 12th-grade girls. Data on physical activity facilities and resources in the participating communities were collected using a variety of methods. Physical activity resources within a 0.75-mile street-network buffer around each girl's home were counted using ArcGIS, version 9.1. Mixed-model regression models were used to determine if there was a relationship between three physical activity variables and the number of physical activity resources within the 0.75-mile buffer. Data were collected in 2002-2003 and analyzed in 2006-2007. On average, 3.5 physical activity resources (e.g., schools, parks, commercial facilities) were located within the 0.75-mile street-network buffer. Thirty-six percent of the girls had no physical activity resource within the buffer. When multiple physical activity resources were considered, the number of commercial physical activity facilities was significantly associated with reported vigorous physical activity, and the number of parks was associated with total METs in white girls. Multiple physical activity resources within a 0.75-mile street-network buffer around adolescent girls' homes are associated physical activity in those girls. Several types of resources are associated with vigorous physical activity and total activity in adolescent girls. Future studies should examine the temporal and causal relationships between the physical environment, physical activity, and health outcomes related to

Perceived and Police Reported Neighborhood Crime: Linkages to Adolescent Activity Behaviors and Weight Status

PubMed Central

Wall, Melanie; Choo, Tse; Larson, Nicole; Van Riper, David; Neumark-Sztainer, Dianne

2015-01-01

Purpose Inadequate physical activity and obesity during adolescence are areas of public health concern. Questions exist about the role of neighborhoods in the etiology of these problems. This research addressed the relationships of perceived and objective reports of neighborhood crime to adolescent physical activity, screen media use, and BMI. Methods Socioeconomically and racially/ethnically diverse adolescents (N=2,455, 53.4% female) from 20 urban, public middle and high schools in Minneapolis/St. Paul, Minnesota responded to a classroom survey in the EAT 2010 (Eating and Activity in Teens) study. Body mass index (BMI) was measured by research staff. Participants’ mean age was 14.6 (SD=2.0); 82.7% represented racial/ethnic groups other than non-Hispanic white. Linear regressions examined associations between crime perceived by adolescents and crime reported to police and the outcomes of interest (BMI z-scores, physical activity, and screen time). Models were stratified by gender and adjusted for age, race/ethnicity, socioeconomic status, and school. Results BMI was positively associated with perceived crime among girls and boys and with reported crime in girls. For girls, there was an association between higher perceived crime and increased screen time; for boys, between higher reported property crime and reduced physical activity. Perceived crime was associated with reported crime, both property and personal, in both genders. Conclusions Few prior studies of adolescents have studied the association between both perceived and reported crime and BMI. Community-based programs for youth should consider addressing adolescents’ safety concerns along with other perceived barriers to physical activity. Interventions targeting actual crime rates are also important. PMID:26206444

Perceived and Police-Reported Neighborhood Crime: Linkages to Adolescent Activity Behaviors and Weight Status.

PubMed

Forsyth, Ann; Wall, Melanie; Choo, Tse; Larson, Nicole; Van Riper, David; Neumark-Sztainer, Dianne

2015-08-01

Inadequate physical activity and obesity during adolescence are areas of public health concern. Questions exist about the role of neighborhoods in the etiology of these problems. This research addressed the relationships of perceived and objective reports of neighborhood crime to adolescent physical activity, screen media use, and body mass index (BMI). Socioeconomically and racially/ethnically diverse adolescents (N = 2,455, 53.4% female) from 20 urban, public middle and high schools in Minneapolis/St. Paul, Minnesota responded to a classroom survey in the Eating and Activity in Teens 2010 study. BMI was measured by research staff. Participants' mean age was 14.6 (standard deviation = 2.0); 82.7% represented racial/ethnic groups other than non-Hispanic white. Linear regressions examined associations between crime perceived by adolescents and crime reported to police and the outcomes of interest (BMI z-scores, physical activity, and screen time). Models were stratified by gender and adjusted for age, race/ethnicity, socioeconomic status, and school. BMI was positively associated with perceived crime among girls and boys and with reported crime in girls. For girls, there was an association between higher perceived crime and increased screen time; for boys, between higher reported property crime and reduced physical activity. Perceived crime was associated with reported crime, both property and personal, in both genders. Few prior studies of adolescents have studied the association between both perceived and reported crime and BMI. Community-based programs for youth should consider addressing adolescents' safety concerns along with other perceived barriers to physical activity. Interventions targeting actual crime rates are also important. Copyright © 2015 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Reprogramming the Chemodiversity of Terpenoid Cyclization by Remolding the Active Site Contour of epi-Isozizaene Synthase

PubMed Central

2015-01-01

The class I terpenoid cyclase epi-isozizaene synthase (EIZS) utilizes the universal achiral isoprenoid substrate, farnesyl diphosphate, to generate epi-isozizaene as the predominant sesquiterpene cyclization product and at least five minor sesquiterpene products, making EIZS an ideal platform for the exploration of fidelity and promiscuity in a terpenoid cyclization reaction. The hydrophobic active site contour of EIZS serves as a template that enforces a single substrate conformation, and chaperones subsequently formed carbocation intermediates through a well-defined mechanistic sequence. Here, we have used the crystal structure of EIZS as a guide to systematically remold the hydrophobic active site contour in a library of 26 site-specific mutants. Remolded cyclization templates reprogram the reaction cascade not only by reproportioning products generated by the wild-type enzyme but also by generating completely new products of diverse structure. Specifically, we have tripled the overall number of characterized products generated by EIZS. Moreover, we have converted EIZS into six different sesquiterpene synthases: F96A EIZS is an (E)-β-farnesene synthase, F96W EIZS is a zizaene synthase, F95H EIZS is a β-curcumene synthase, F95M EIZS is a β-acoradiene synthase, F198L EIZS is a β-cedrene synthase, and F96V EIZS and W203F EIZS are (Z)-γ-bisabolene synthases. Active site aromatic residues appear to be hot spots for reprogramming the cyclization cascade by manipulating the stability and conformation of critical carbocation intermediates. A majority of mutant enzymes exhibit only relatively modest 2–100-fold losses of catalytic activity, suggesting that residues responsible for triggering substrate ionization readily tolerate mutations deeper in the active site cavity. PMID:24517311

Objective and subjective measures of neighborhood environment (NE): relationships with transportation physical activity among older persons.

PubMed

Nyunt, Ma Shwe Zin; Shuvo, Faysal Kabir; Eng, Jia Yen; Yap, Keng Bee; Scherer, Samuel; Hee, Li Min; Chan, Siew Pang; Ng, Tze Pin

2015-09-15

This study examined the associations of subjective and objective measures of the neighbourhood environment with the transportation physical activity of community-dwelling older persons in Singapore. A modified version of the Neighborhood Environment Walkability Scale (NEWS) and Geographical Information System (GIS) measures of the built environment characteristics were related to the frequency of walking for transportation purpose in a study sample of older persons living in high-density apartment blocks within a public housing estate in Singapore. Relevant measured variables to assess the complex relationships among built environment measures and transportation physical activity were examined using structural equation modelling and multiple regression analyses. The subjective measures of residential density, street connectivity, land use mix diversity and aesthetic environment and the objective GIS measure of Accessibility Index have positively significant independent associations with transportation physical activity, after adjusting for demographics, socio-economic and health status. Subjective and objective measures are non-overlapping measures complementing each other in providing information on built environment characteristics. For elderly living in a high-density urban neighborhood, well connected street, diversity of land use mix, close proximity to amenities and facilities, and aesthetic environment were associated with higher frequency of walking for transportation purposes.

Neighborhood socioeconomic deprivation, perceived neighborhood factors, and cortisol responses to induced stress among healthy adults.

PubMed

Barrington, Wendy E; Stafford, Mai; Hamer, Mark; Beresford, Shirley A A; Koepsell, Thomas; Steptoe, Andrew

2014-05-01

Associations between measures of neighborhood socioeconomic deprivation and health have been identified, yet work is needed to uncover explanatory mechanisms. One hypothesized pathway is through stress, yet the few studies that have evaluated associations between characteristics of deprived neighborhoods and biomarkers of stress are mixed. This study evaluated whether objectively measured neighborhood socioeconomic deprivation and individual perceived neighborhood characteristics (i.e. social control and fear of crime) impacted cortisol responses to an induced stressor among older healthy adults. Data from Heart Scan, a sub-study of the Whitehall II cohort, were used to generate multilevel piecewise growth-curve models of cortisol trajectories after a laboratory stressor accounting for neighborhood and demographic characteristics. Neighborhood socioeconomic deprivation was significantly associated with individual perceptions of social control and fear of crime in the neighborhood while an association with blunted cortisol reactivity was only evidence among women. Social control was significantly associated with greater cortisol reactivity and mediation between neighborhood socioeconomic deprivation and cortisol reactivity was suggested among women. These findings support a gender-dependent role of neighborhood in stress process models of health. Published by Elsevier Ltd.

An Active Contour Model Based on Adaptive Threshold for Extraction of Cerebral Vascular Structures.

PubMed

Wang, Jiaxin; Zhao, Shifeng; Liu, Zifeng; Tian, Yun; Duan, Fuqing; Pan, Yutong

2016-01-01

Cerebral vessel segmentation is essential and helpful for the clinical diagnosis and the related research. However, automatic segmentation of brain vessels remains challenging because of the variable vessel shape and high complex of vessel geometry. This study proposes a new active contour model (ACM) implemented by the level-set method for segmenting vessels from TOF-MRA data. The energy function of the new model, combining both region intensity and boundary information, is composed of two region terms, one boundary term and one penalty term. The global threshold representing the lower gray boundary of the target object by maximum intensity projection (MIP) is defined in the first-region term, and it is used to guide the segmentation of the thick vessels. In the second term, a dynamic intensity threshold is employed to extract the tiny vessels. The boundary term is used to drive the contours to evolve towards the boundaries with high gradients. The penalty term is used to avoid reinitialization of the level-set function. Experimental results on 10 clinical brain data sets demonstrate that our method is not only able to achieve better Dice Similarity Coefficient than the global threshold based method and localized hybrid level-set method but also able to extract whole cerebral vessel trees, including the thin vessels.

Development of a pedestrian audit tool to assess rural neighborhood walkability.

PubMed

Scanlin, Kathleen; Haardoerfer, Regine; Kegler, Michelle C; Glanz, Karen

2014-08-01

Recently, investigators have begun to refine audit instruments for use in rural areas. However, no studies have developed a walkability summary score or have correlated built environment characteristics with physical activity behavior. The Rural Pedestrian Environmental Audit Instrument was developed specifically for use in rural areas. Segments surrounding participant's homes were selected to represent neighborhood streets (N = 116). Interrater reliability was conducted on a subset of streets (N = 42). Rural-specific domain and walkability scores were developed and correlated with individual-level data on perceptions of the neighborhood and self-reported physical activity behavior. Interrater reliability for the instrument was substantial and all domains had high agreement. Walkability in the audited area was low with even the best segments demonstrating only moderate support for walking. There were no significant correlations between the neighborhood walkability score and self-reported neighborhood walkability, time spent walking, sedentary behavior, or BMI; however, a few correlations within the social/dynamic domain were significant. This study expands recent research refining audit instruments for rural areas. Findings suggest the usefulness of summarizing environmental data at the domain level and linking it to physical activity behavior to identify aspects of the neighborhood environment that are most strongly correlated with actual behavior.

Reconsidering access: park facilities and neighborhood disamenities in New York City.

PubMed

Weiss, Christopher C; Purciel, Marnie; Bader, Michael; Quinn, James W; Lovasi, Gina; Neckerman, Kathryn M; Rundle, Andrew G

2011-04-01

With increasing concern about rising rates of obesity, public health researchers have begun to examine the availability of parks and other spaces for physical activity, particularly in cities, to assess whether access to parks reduces the risk of obesity. Much of the research in this field has shown that proximity to parks may support increased physical activity in urban environments; however, as yet, there has been limited consideration of environmental impediments or disamenities that might influence individuals' perceptions or usage of public recreation opportunities. Prior research suggests that neighborhood disamenities, for instance crime, pedestrian safety, and noxious land uses, might dissuade people from using parks or recreational facilities and vary by neighborhood composition. Motivated by such research, this study estimates the relationship between neighborhood compositional characteristics and measures of park facilities, controlling for variation in neighborhood disamenities, using geographic information systems (GIS) data for New York City parks and employing both kernel density estimation and distance measures. The central finding is that attention to neighborhood disamenities can appreciably alter the relationship between neighborhood composition and spatial access to parks. Policy efforts to enhance the recreational opportunities in urban areas should expand beyond a focus on availability to consider also the hazards and disincentives that may influence park usage.

Neighborhood walkability and walking behavior: the moderating role of action orientation.

PubMed

Friederichs, Stijn A H; Kremers, Stef P J; Lechner, Lilian; de Vries, Nanne K

2013-05-01

In promoting physical activity, it is important to gain insight into environmental factors that facilitate or hinder physical activity and factors that may influence this environment-behavior relationship. As the personality factor of action orientation reflects an individual's capacity to regulate behavior it may act as a moderator in the environment-behavior relationship. The current study addressed the relationship between neighborhood walkability and walking behavior and the influence of action orientation on this relationship. Three hundred and forty-seven Dutch inhabitants [mean age 43.1 (SD 17.1)] completed a web based questionnaire assessing demographic variables, neighborhood walkability (Neighborhood Environment Walkability Scale), variables of the Theory of Planned Behavior, action orientation, and walking behavior. The results show that high levels of neighborhood walkability are positively associated with walking behavior and that this influence is largely unmediated by cognitive processes. A positive influence of neighborhood walkability on walking behavior was identified in the action-oriented subpopulation, whereas in the state-oriented part of the population, this influence was absent. The findings suggest that the influence of neighborhood environment on walking behavior has a relatively large unconscious, automatic component. In addition, the results suggest that the walkability-walking relationship is moderated by action orientation.

The association between neighborhood socioeconomic disadvantage and high-risk injection behavior among people who inject drugs.

PubMed

DeCuir, Jennifer; Lovasi, Gina S; El-Sayed, Abdulrahman; Lewis, Crystal Fuller

2018-02-01

Although much research has been conducted on the determinants of HIV risk behavior among people who inject drugs (PWID), the influence of the neighborhood context on high-risk injection behavior remains understudied. To address this gap in the literature, we measured associations between neighborhood socioeconomic disadvantage and high-risk injection behavior, and determined whether these associations were modified by drug-related police activity and syringe exchange program (SEP) accessibility. Our sample was comprised of 484 pharmacy-recruited PWID in New York City. Measures of neighborhood socioeconomic disadvantage were created using data from the 2006-2010 American Community Survey. Associations with high-risk injection behavior were estimated using multivariable Poisson regression. Effect modification by drug-related police activity and SEP accessibility was assessed by entering cross-product terms into adjusted models of high-risk injection behavior. Neighborhood socioeconomic disadvantage was associated with decreased receptive syringe sharing and unsterile syringe use. In neighborhoods with high drug-related police activity, associations between neighborhood disadvantage and unsterile syringe use were attenuated to the null. In neighborhoods with high SEP accessibility, neighborhood disadvantage was associated with decreased acquisition of syringes from an unsafe source. PWID in disadvantaged neighborhoods reported safer injection behaviors than their counterparts in neighborhoods that were relatively better off. The contrasting patterns of effect modification by SEP accessibility and drug-related police activity support the use of harm reduction approaches over law enforcement-based strategies for the control of blood borne virus transmission among PWID in disadvantaged urban areas. Copyright © 2017 Elsevier B.V. All rights reserved.

Neighborhood characteristics and TV viewing in youth: nothing to do but watch TV?

PubMed

Timperio, Anna; Salmon, Jo; Ball, Kylie; te Velde, Saskia J; Brug, Johannes; Crawford, David

2012-03-01

Neighborhoods that discourage physical activity may encourage indoor activities such as television viewing; however few studies have examined associations between neighborhood characteristics and sedentary activities. This study examined cross-sectional and longitudinal associations between perceived and objective measures of the physical and social neighborhood environment and TV viewing among children and adolescents. Cross-sectional and longitudinal. Parents of 190 children and 169 adolescents completed questionnaire items regarding facilities for physical activity, neighborhood safety (general and traffic), social trust/cohesion, social networks and their child's TV viewing in 2006. Adolescents self-reported their TV viewing. Objective measures of reported crime and neighborhood destinations, road connectivity and traffic exposure were also collected. Questions about TV viewing were repeated in 2008 (longitudinal sample: 157 children; 105 adolescents). In children, cul-de-sac density and reported crime were positively and parental agreement that their neighborhood has good sporting facilities was negatively associated with TV viewing in cross-sectional analyses. There were no longitudinal associations among children. In adolescents, number of sports options and parental agreement that there is so much traffic that it is difficult/unpleasant for their child to walk were negatively associated with TV viewing 2 years later. Crime and a lack of quality sporting facilities or options may contribute to greater TV viewing among youth. Copyright © 2011 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Reclaiming streets for outdoor play: A process and impact evaluation of “Juega en tu Barrio” (Play in your Neighborhood), an intervention to increase physical activity and opportunities for play

PubMed Central

Albagli, Andrea; Sadarangani, Kabir P.; Aguilar-Farias, Nicolas

2017-01-01

Background New strategies are required to create supportive physical and social environments for children and promote active free-play. Juega en tu Barrio (JETB; Play in your Neighborhood) was designed and implemented to explore the effectiveness of closing a street in a low-to-middle income neighborhood in order to increase children’s outside play and physical activity. Methods A pretest-posttest design with control group was employed to investigate the intervention effects in a subsample of 100 children, 51 from the intervention neighborhood and 49 from the control neighborhood. The children wore pedometers for one week, and their parents completed questionnaires at two time points: before the intervention began and during the last two weeks of the intervention. JETB was conducted in the intervention neighborhood from 17:30 to 20:30, twice a week, from September to December 2014. Stewards ensured that the children were safe. Children and adults were assessed using systematic observation. Results The intervention and control neighborhoods included 177 and 116 children respectively. The average attendance per event was 60 children (SD = 22, reach 34%). In the intervention neighborhood, a significant increase between baseline and final assessment was observed in after-school outdoor playtime (p = 0.02), steps during the 3-hour intervention (p = 0.004), and daily steps Monday to Sunday (p = 0.006). Meanwhile, no changes were observed in the control neighborhood for the same variables. The proportion of children who met recommended daily step counts increased from 27.5% to 53.0% in the intervention neighborhood (p = 0.007), while for control neighborhood no difference was observed (49.0% to 53.0% p = 0.804). Conclusions JETB showed high community engagement while offering opportunities for increased outdoor play in children. The intervention showed a significant effect on the number of children meeting the daily pedometer-derived physical activity recommendations

Does the Neighborhood Context Alter the Link between Youth's After-School Time Activities and Developmental Outcomes? A Multilevel Analysis

ERIC Educational Resources Information Center

Fauth, Rebecca C.; Roth, Jodie L.; Brooks-Gunn, Jeanne

2007-01-01

This article examines links between different measures of after-school time activity participation (5 specific activities and breadth) on youth's developmental outcomes (anxiety/depression, delinquency, and substance use) over 6 years and whether these links are moderated by neighborhood-level variables. The sample (N = 1,315) of 9- and…

Connecting Schools to Neighborhood Revitalization: The Case of the Maple Heights Neighborhood Association

ERIC Educational Resources Information Center

Pesch, Lawrence P.

2014-01-01

This case study focuses on the way a neighborhood association connects schools to broad change in an urban neighborhood of a large Midwestern city. The first section provides a review of the literature on community involvement in school and neighborhood reform. It reviews the historical origins of the current school-community relationship, the…

Differential contribution of early visual areas to the perceptual process of contour processing.

PubMed

Schira, Mark M; Fahle, Manfred; Donner, Tobias H; Kraft, Antje; Brandt, Stephan A

2004-04-01

We investigated contour processing and figure-ground detection within human retinotopic areas using event-related functional magnetic resonance imaging (fMRI) in 6 healthy and naïve subjects. A figure (6 degrees side length) was created by a 2nd-order texture contour. An independent and demanding foveal letter-discrimination task prevented subjects from noticing this more peripheral contour stimulus. The contour subdivided our stimulus into a figure and a ground. Using localizers and retinotopic mapping stimuli we were able to subdivide each early visual area into 3 eccentricity regions corresponding to 1) the central figure, 2) the area along the contour, and 3) the background. In these subregions we investigated the hemodynamic responses to our stimuli and compared responses with or without the contour defining the figure. No contour-related blood oxygenation level-dependent modulation in early visual areas V1, V3, VP, and MT+ was found. Significant signal modulation in the contour subregions of V2v, V2d, V3a, and LO occurred. This activation pattern was different from comparable studies, which might be attributable to the letter-discrimination task reducing confounding attentional modulation. In V3a, but not in any other retinotopic area, signal modulation corresponding to the central figure could be detected. Such contextual modulation will be discussed in light of the recurrent processing hypothesis and the role of visual awareness.

Development of a 15-Item Scale to Measure Parental Perceptions of Their Neighborhood

ERIC Educational Resources Information Center

Quigg, Robin; Gray, Andrew; Reeder, Anthony Ivor; Holt, Alec; Waters, Debra L.

2015-01-01

Socioecological theory suggests that there are a range of influences that affect the physical activity levels of children, including parents' perceptions of the neighborhood. A questionnaire instrument to quantify parental neighborhood perceptions was developed for the Location of Children's Activity in Their Environment study as a potential…

Neighborhood Differences in Post-Stroke Mortality

PubMed Central

Osypuk, Theresa L.; Ehntholt, Amy; Moon, J. Robin; Gilsanz, Paola; Glymour, M. Maria

2017-01-01

Background Post-stroke mortality is higher among residents of disadvantaged neighborhoods, but it is not known whether neighborhood inequalities are specific to stroke survival or similar to mortality patterns in the general population. We hypothesized that neighborhood disadvantage would predict higher post-stroke mortality and neighborhood effects would be relatively larger for stroke patients than for individuals with no history of stroke. Methods and Results Health and Retirement Study participants aged 50+ without stroke at baseline (n=15,560) were followed up to 12 years for incident stroke (1,715 events over 159,286 person-years) and mortality (5,325 deaths). Baseline neighborhood characteristics included objective measures based on census tracts (family income, poverty, deprivation, residential stability, and percent white, black or foreign-born) and self-reported neighborhood social ties. Using Cox proportional hazard models, we compared neighborhood mortality effects for people with versus without a history of stroke. Most neighborhood variables predicted mortality for both stroke patients and the general population in demographic-adjusted models. Neighborhood percent white predicted lower mortality for stroke survivors (HR=0.75 for neighborhoods in highest 25th percentile vs. below, 95 % CI: 0.62, 0.91) more strongly than for stroke-free adults (HR=0.92 (0.83, 1.02); p=0.04 for stroke-by-neighborhood interaction). No other neighborhood characteristic had different effects for people with versus without stroke. Neighborhood-mortality associations emerged within three months after stroke, when associations were often stronger than among stroke-free individuals. Conclusions Neighborhood characteristics predict post-stroke mortality, but most effects are similar for individuals without stroke. Eliminating disparities in stroke survival may require addressing pathways that are not specific to traditional post-stroke care. PMID:28228449

47 CFR 73.311 - Field strength contours.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 4 2010-10-01 2010-10-01 false Field strength contours. 73.311 Section 73.311... Broadcast Stations § 73.311 Field strength contours. (a) Applications for FM broadcast authorizations must show the field strength contours required by FCC Form 301 or FCC Form 340, as appropriate. (b) The...

47 CFR 73.311 - Field strength contours.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 4 2011-10-01 2011-10-01 false Field strength contours. 73.311 Section 73.311... Broadcast Stations § 73.311 Field strength contours. (a) Applications for FM broadcast authorizations must show the field strength contours required by FCC Form 301 or FCC Form 340, as appropriate. (b) The...

Chromospherically Active Stars in the RAVE Survey. II. Young Dwarfs in the Solar Neighborhood

NASA Astrophysics Data System (ADS)

Žerjal, M.; Zwitter, T.; Matijevič, G.; Grebel, E. K.; Kordopatis, G.; Munari, U.; Seabroke, G.; Steinmetz, M.; Wojno, J.; Bienaymé, O.; Bland-Hawthorn, J.; Conrad, C.; Freeman, K. C.; Gibson, B. K.; Gilmore, G.; Kunder, A.; Navarro, J.; Parker, Q. A.; Reid, W.; Siviero, A.; Watson, F. G.; Wyse, R. F. G.

2017-01-01

A large sample of over 38,000 chromospherically active candidate solar-like stars and cooler dwarfs from the RAVE survey is addressed in this paper. An improved activity identification with respect to the previous study was introduced to build a catalog of field stars in the solar neighborhood with an excess emission flux in the calcium infrared triplet wavelength region. The central result of this work is the calibration of the age-activity relation for main-sequence dwarfs in a range from a few 10 {Myr} up to a few Gyr. It enabled an order of magnitude age estimation of the entire active sample. Almost 15,000 stars are shown to be younger than 1 {Gyr} and ˜2000 younger than 100 {Myr}. The young age of the most active stars is confirmed by their position off the main sequence in the J - K versus {N}{UV}-V diagram showing strong ultraviolet excess, mid-infrared excess in the J - K versus {W}1-{W}2 diagram, and very cool temperatures (J-K> 0.7). They overlap with the reference pre-main-sequence RAVE stars often displaying X-ray emission. The activity level increasing with the color reveals their different nature from the solar-like stars and probably represents an underlying dynamo-generating magnetic fields in cool stars. Of the RAVE objects from DR5, 50% are found in the TGAS catalog and supplemented with accurate parallaxes and proper motions by Gaia. This makes the database of a large number of young stars in a combination with RAVE’s radial velocities directly useful as a tracer of the very recent large-scale star formation history in the solar neighborhood. The data are available online in the Vizier database.

Collinear facilitation and contour integration in autism: evidence for atypical visual integration.

PubMed

Jachim, Stephen; Warren, Paul A; McLoughlin, Niall; Gowen, Emma

2015-01-01

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by impaired social interaction, atypical communication and a restricted repertoire of interests and activities. Altered sensory and perceptual experiences are also common, and a notable perceptual difference between individuals with ASD and controls is their superior performance in visual tasks where it may be beneficial to ignore global context. This superiority may be the result of atypical integrative processing. To explore this claim we investigated visual integration in adults with ASD (diagnosed with Asperger's Syndrome) using two psychophysical tasks thought to rely on integrative processing-collinear facilitation and contour integration. We measured collinear facilitation at different flanker orientation offsets and contour integration for both open and closed contours. Our results indicate that compared to matched controls, ASD participants show (i) reduced collinear facilitation, despite equivalent performance without flankers; and (ii) less benefit from closed contours in contour integration. These results indicate weaker visuospatial integration in adults with ASD and suggest that further studies using these types of paradigms would provide knowledge on how contextual processing is altered in ASD.

The Child Care Challenge: Models for Child Care Services. Neighborhood Networks.

ERIC Educational Resources Information Center

Department of Housing and Urban Development, Washington, DC. Office of Multifamily Housing.

Neighborhood Networks is a community-based initiative established by the U.S. Department of Housing and Urban Development (HUD) to provide residents of HUD-assisted or insured properties with programs, activities, and training promoting economic self-sufficiency. This booklet provides Neighborhood Networks centers information on successful models…

Superpixel guided active contour segmentation of retinal layers in OCT volumes

NASA Astrophysics Data System (ADS)

Bai, Fangliang; Gibson, Stuart J.; Marques, Manuel J.; Podoleanu, Adrian

2018-03-01

Retinal OCT image segmentation is a precursor to subsequent medical diagnosis by a clinician or machine learning algorithm. In the last decade, many algorithms have been proposed to detect retinal layer boundaries and simplify the image representation. Inspired by the recent success of superpixel methods for pre-processing natural images, we present a novel framework for segmentation of retinal layers in OCT volume data. In our framework, the region of interest (e.g. the fovea) is located using an adaptive-curve method. The cell layer boundaries are then robustly detected firstly using 1D superpixels, applied to A-scans, and then fitting active contours in B-scan images. Thereafter the 3D cell layer surfaces are efficiently segmented from the volume data. The framework was tested on healthy eye data and we show that it is capable of segmenting up to 12 layers. The experimental results imply the effectiveness of proposed method and indicate its robustness to low image resolution and intrinsic speckle noise.

Are features of the neighborhood environment associated with disability in older adults?

PubMed

White, Daniel K; Jette, Alan M; Felson, David T; Lavalley, Michael P; Lewis, Cora E; Torner, James C; Nevitt, Michael C; Keysor, Julie J

2010-01-01

To explore the association of features of a person's neighborhood environment with disability in daily activities. We recruited 436 people aged 65 years and over (mean 70.4 years (SD = 3.9)) with functional limitations from the Multicenter Osteoarthritis Study (MOST). Features of the neighborhood environment were assessed using the Home and Community Environment (HACE) survey. The Late-Life Disability Instrument (LLDI) was used to assess disability in daily activities. We used logistic regression to examine the association of individual environmental features with disability. RESULTS. Older adults whose neighborhoods did not have parks and walking areas less frequently engaged in a regular fitness program (OR = 0.4, 95% CI (0.2, 0.7)), and in social activities (OR = 0.5, 95% CI (0.3, 1.0)). Those whose neighborhoods had adequate handicap parking had 1.5-1.8 higher odds of engagement in several social and work role activities. The presence of public transportation was associated with 1.5-2.9 higher odds of not feeling limited in social, leisure, and work role activities, and instrumental activities of daily living. Our exploratory study suggests that parks and walking areas, adequate handicap parking, and public transportation are associated with disability in older adults.

Are features of the neighborhood environment associated with disability in older adults?

PubMed Central

Jette, Alan M.; Felson, David T.; LaValley, Michael P.; Lewis, Cora E.; Torner, James C.; Nevitt, Michael C.; Keysor, Julie J.

2010-01-01

Purpose To explore the association of features of a person’s neighborhood environment with disability in daily activities. Method We recruited 436 people age 65 years and over (mean 70.4 years (sd=3.9)) with functional limitations from the Multicenter Osteoarthritis Study (MOST). Features of the neighborhood environment were assessed using the Home and Community Environment (HACE) survey. The Late-Life Disability Instrument (LLDI) was used to assess disability in daily activities. We used logistic regression to examine the association of individual environmental features with disability. Results Older adults whose neighborhoods did not have parks and walking areas less frequently engaged in a regular fitness program (OR=0.4, 95%CI [0.2 0.7]), and in social activities (OR= 0.5, 95%CI [0.3 1.0]). Those whose neighborhoods had adequate handicap parking had 1.5 to 1.8 higher odds of engagement in several social and work role activities. The presence of public transportation was associated with 1.5 to 2.9 higher odds of not feeling limited in social, leisure, and work role activities, and instrumental activities of daily living. Conclusion Our exploratory study suggests that parks and walking areas, adequate handicap parking, and public transportation are associated with disability in older adults. PMID:20205576

Walking to Work: The Roles of Neighborhood Walkability and Socioeconomic Deprivation.

PubMed

Kelly, Cheryl M; Lian, Min; Struthers, Jim; Kammrath, Anna

2015-06-16

There are few studies that aimed to find a relationship between transportation-related physical activity and neighborhood socioeconomic condition using a composite deprivation index. The purpose of this study is to assess the relationship of neighborhood walkability and socioeconomic deprivation with percentage of adults walking to work. A walkability index and a socioeconomic deprivation index were created at block group-level. The outcome variable, percentage of adults who walk to work was dichotomized as < 5% of the block group walking to work low and ≥ 5% of the block group walking to work as high and applied logistic regression to examine the association of walkability and socioeconomic deprivation with walking to work. Individuals in the most walkable neighborhoods are almost 5 times more likely to walk to work than individuals in the least walkable neighborhoods (OR = 4.90, 95% CI = 2.80-8.59). After adjusting for neighborhood socioeconomic deprivation, individuals in the most walkable neighborhoods are almost 3 times more likely to walk to work than individuals in the least walkable neighborhoods (OR = 2.98, 95% CI = 1.62-5.49). Walkability (as measured by the walkability index) is a very strong indicator of walking to work even after controlling for neighborhood socioeconomic disadvantage.

Neighborhood environment perceptions and the likelihood of smoking and alcohol use.

PubMed

Jitnarin, Nattinee; Heinrich, Katie M; Haddock, Christopher K; Hughey, Joseph; Berkel, LaVerne; Poston, Walker S C

2015-01-14

Neighborhood characteristics are important correlates for a variety of health outcomes. Among several health risk behaviors, smoking and alcohol use have significant consequences. Perceptions of neighborhood problems are associated with depressive symptoms, lower physical activity, and lower quality of life. However, it is unclear which perceived aspects of neighborhoods might be related to smoking and drinking. We examined whether perceived neighborhood characteristics were associated with smoking and drinking patterns using data from US metropolitan Midwestern area adults. Participants completed surveys including sociodemographic characteristics, neighborhood perceptions, behavioral and psychological health. For men, negative perceptions of neighborhood infrastructures were significant predictors for smoking and binge drinking. Among women, no perceived environmental factors were associated with smoking or drinking. However, education was a significant negative predictor for smoking. As age increased, the likelihood of using cigarettes, heavy and binge drinking in women decreased significantly. Depression was a positive predictor for smoking and heavy drinking in men and women, respectively. These findings indicate that the perceived neighborhood infrastructure was predictive of health behaviors among men, even after adjusting for key confounders. Closer attention may need to be paid to the role of neighborhood environmental characteristics along with individual-level characteristics in influencing unhealthy behaviors.

Who Moves to Mixed-Income Neighborhoods?*

PubMed Central

McKinnish, Terra; White, T. Kirk

2011-01-01

This paper uses confidential Census data, specifically the 1990 and 2000 Census Long Form data, to study the income dispersion of recent cohorts of migrants to mixed-income neighborhoods. We investigate whether neighborhoods with high levels of income dispersion attract economically diverse in-migrants. If recent in-migrants to mixed-income neighborhoods exhibit high levels of income dispersion, this is consistent with stable mixed-income neighborhoods. If, however, mixed-income neighborhoods are comprised of homogenous low-income (high-income) cohorts of long-term residents combined with homogenous high-income (low-income) cohorts of recent arrivals, this is consistent with neighborhood transition. Our results indicate that neighborhoods with high levels of income dispersion do in fact attract a much more heterogeneous set of in-migrants, particularly from the tails of the income distribution. Our results also suggest that the residents of mixed-income neighborhoods may be less heterogeneous with respect to lifetime income. PMID:21479114

Association between neighborhood socioeconomic status and screen time among pre-school children: a cross-sectional study

PubMed Central

2010-01-01

Background Sedentary behavior is considered a separate construct from physical activity and engaging in sedentary behaviors results in health effects independent of physical activity levels. A major source of sedentary behavior in children is time spent viewing TV or movies, playing video games, and using computers. To date no study has examined the impact of neighborhood socioeconomic status (SES) on pre-school children's screen time behavior. Methods Proxy reports of weekday and weekend screen time (TV/movies, video games, and computer use) were completed by 1633 parents on their 4-5 year-old children in Edmonton, Alberta between November, 2005 and August, 2007. Postal codes were used to classified neighborhoods into low, medium or high SES. Multiple linear and logistic regression models were conducted to examine relationships between screen time and neighborhood SES. Results Girls living in low SES neighborhoods engaged in significantly more weekly overall screen time and TV/movie minutes compared to girls living in high SES neighborhoods. The same relationship was not observed in boys. Children living in low SES neighborhoods were significantly more likely to be video game users and less likely to be computer users compared to children living in high SES neighborhoods. Also, children living in medium SES neighborhoods were significantly less likely to be computer users compared to children living in high SES neighborhoods. Conclusions Some consideration should be given to providing alternative activity opportunities for children, especially girls who live in lower SES neighborhoods. Also, future research should continue to investigate the independent effects of neighborhood SES on screen time as well as the potential mediating variables for this relationship. PMID:20573262

The Role of Immigrant Concentration Within and Beyond Residential Neighborhoods in Adolescent Alcohol Use

PubMed Central

Jackson, Aubrey L.; Browning, Christopher R.; Krivo, Lauren J.; Kwan, Mei-Po; Washington, Heather M.

2015-01-01

Neighborhoods are salient contexts for youth that shape adolescent development partly through informal social controls on their behavior. This research examines how immigrant concentration within and beyond the residential neighborhood influences adolescent alcohol use. Residential neighborhood immigrant concentration may lead to a cohesive, enclave-like community that protects against adolescent alcohol use. But heterogeneity in the immigrant concentrations characterizing the places residents visit as they engage in routine activities outside of the neighborhood where they live may weaken the social control benefits of the social ties and shared cultural orientations present in enclave communities. This study investigates whether the protective influence of residential neighborhood immigrant concentration on adolescent alcohol consumption diminishes when youth live in communities where residents collectively are exposed to areas with more diverse immigrant concentrations. This study tests this contention by analyzing survey and geographic routine activity space data from the Los Angeles Family and Neighborhood Survey, and the 2000 census. The sample includes 793 adolescents (48.7% female, 16.5% foreign-born Latino, 42.5% US-born Latino, 11.0% black, 30% white/other) between the ages of 12 and 17 who live in 65 neighborhoods in Los Angeles County. Immigrant concentration among these neighborhoods derives primarily from Latin America. The results from multilevel models show that immigrant concentration protects against adolescent alcohol use only when there is low neighborhood-level diversity of exposures to immigrant concentration among the contexts residents visit outside of their residential neighborhood. This research highlights the importance of considering the effects of aggregate exposures to non-home contexts on adolescent wellbeing. PMID:26215378

Brachial artery vasomotion and transducer pressure effect on measurements by active contour segmentation on ultrasound

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

Cary, Theodore W.; Sultan, Laith R.; Sehgal, Chandra M., E-mail: sehgalc@uphs.upenn.edu

Purpose: To use feed-forward active contours (snakes) to track and measure brachial artery vasomotion on ultrasound images recorded in both transverse and longitudinal views; and to compare the algorithm's performance in each view. Methods: Longitudinal and transverse view ultrasound image sequences of 45 brachial arteries were segmented by feed-forward active contour (FFAC). The segmented regions were used to measure vasomotion artery diameter, cross-sectional area, and distention both as peak-to-peak diameter and as area. ECG waveforms were also simultaneously extracted frame-by-frame by thresholding a running finite-difference image between consecutive images. The arterial and ECG waveforms were compared as they traced eachmore » phase of the cardiac cycle. Results: FFAC successfully segmented arteries in longitudinal and transverse views in all 45 cases. The automated analysis took significantly less time than manual tracing, but produced superior, well-behaved arterial waveforms. Automated arterial measurements also had lower interobserver variability as measured by correlation, difference in mean values, and coefficient of variation. Although FFAC successfully segmented both the longitudinal and transverse images, transverse measurements were less variable. The cross-sectional area computed from the longitudinal images was 27% lower than the area measured from transverse images, possibly due to the compression of the artery along the image depth by transducer pressure. Conclusions: FFAC is a robust and sensitive vasomotion segmentation algorithm in both transverse and longitudinal views. Transverse imaging may offer advantages over longitudinal imaging: transverse measurements are more consistent, possibly because the method is less sensitive to variations in transducer pressure during imaging.« less

Brachial artery vasomotion and transducer pressure effect on measurements by active contour segmentation on ultrasound.

PubMed

Cary, Theodore W; Reamer, Courtney B; Sultan, Laith R; Mohler, Emile R; Sehgal, Chandra M

2014-02-01

To use feed-forward active contours (snakes) to track and measure brachial artery vasomotion on ultrasound images recorded in both transverse and longitudinal views; and to compare the algorithm's performance in each view. Longitudinal and transverse view ultrasound image sequences of 45 brachial arteries were segmented by feed-forward active contour (FFAC). The segmented regions were used to measure vasomotion artery diameter, cross-sectional area, and distention both as peak-to-peak diameter and as area. ECG waveforms were also simultaneously extracted frame-by-frame by thresholding a running finite-difference image between consecutive images. The arterial and ECG waveforms were compared as they traced each phase of the cardiac cycle. FFAC successfully segmented arteries in longitudinal and transverse views in all 45 cases. The automated analysis took significantly less time than manual tracing, but produced superior, well-behaved arterial waveforms. Automated arterial measurements also had lower interobserver variability as measured by correlation, difference in mean values, and coefficient of variation. Although FFAC successfully segmented both the longitudinal and transverse images, transverse measurements were less variable. The cross-sectional area computed from the longitudinal images was 27% lower than the area measured from transverse images, possibly due to the compression of the artery along the image depth by transducer pressure. FFAC is a robust and sensitive vasomotion segmentation algorithm in both transverse and longitudinal views. Transverse imaging may offer advantages over longitudinal imaging: transverse measurements are more consistent, possibly because the method is less sensitive to variations in transducer pressure during imaging.

Brachial artery vasomotion and transducer pressure effect on measurements by active contour segmentation on ultrasound

PubMed Central

Cary, Theodore W.; Reamer, Courtney B.; Sultan, Laith R.; Mohler, Emile R.; Sehgal, Chandra M.

2014-01-01

Purpose: To use feed-forward active contours (snakes) to track and measure brachial artery vasomotion on ultrasound images recorded in both transverse and longitudinal views; and to compare the algorithm's performance in each view. Methods: Longitudinal and transverse view ultrasound image sequences of 45 brachial arteries were segmented by feed-forward active contour (FFAC). The segmented regions were used to measure vasomotion artery diameter, cross-sectional area, and distention both as peak-to-peak diameter and as area. ECG waveforms were also simultaneously extracted frame-by-frame by thresholding a running finite-difference image between consecutive images. The arterial and ECG waveforms were compared as they traced each phase of the cardiac cycle. Results: FFAC successfully segmented arteries in longitudinal and transverse views in all 45 cases. The automated analysis took significantly less time than manual tracing, but produced superior, well-behaved arterial waveforms. Automated arterial measurements also had lower interobserver variability as measured by correlation, difference in mean values, and coefficient of variation. Although FFAC successfully segmented both the longitudinal and transverse images, transverse measurements were less variable. The cross-sectional area computed from the longitudinal images was 27% lower than the area measured from transverse images, possibly due to the compression of the artery along the image depth by transducer pressure. Conclusions: FFAC is a robust and sensitive vasomotion segmentation algorithm in both transverse and longitudinal views. Transverse imaging may offer advantages over longitudinal imaging: transverse measurements are more consistent, possibly because the method is less sensitive to variations in transducer pressure during imaging. PMID:24506648

Improving Mental Health Through the Regeneration of Deprived Neighborhoods: A Natural Experiment

PubMed Central

White, James; Greene, Giles; Farewell, Daniel; Dunstan, Frank; Rodgers, Sarah; Lyons, Ronan A.; Humphreys, Ioan; John, Ann; Webster, Chris; Phillips, Ceri J.; Fone, David

2017-01-01

Abstract Neighborhood-level interventions provide an opportunity to better understand the impact of neighborhoods on health. In 2001, the Welsh Government, United Kingdom, funded Communities First, a program of neighborhood regeneration delivered to the 100 most deprived of the 881 electoral wards in Wales. In this study, we examined the association between neighborhood regeneration and mental health. Information on regeneration activities in 35 intervention areas (n = 4,197 subjects) and 75 control areas (n = 6,695 subjects) was linked to data on mental health from a cohort study with assessments made in 2001 (before regeneration) and 2008 (after regeneration). Propensity score matching was used to estimate the change in mental health in intervention neighborhoods versus control neighborhoods. Baseline differences between intervention and control areas were of similar magnitude as produced by paired randomization of neighborhoods. Regeneration was associated with an improvement in the mental health of residents in intervention areas compared with control neighborhoods (β = 1.54, 95% confidence interval: 0.50, 2.59), suggesting a reduction in socioeconomic inequalities in mental health. There was a dose-response relationship between length of residence in regeneration neighborhoods and improvements in mental health (P-trend = 0.05). These results show that targeted regeneration of deprived neighborhoods can improve mental health. PMID:28486637

The Relationship Between Neighborhood Socioeconomic Characteristics and Physical Inactivity Among Adolescents Living in Boston, Massachusetts

PubMed Central

Molnar, Beth E.; Cradock, Angie; Kawachi, Ichiro

2014-01-01

Objectives. We sought to determine whether the socioeconomic environment was associated with no participation in physical activity among adolescents in Boston, Massachusetts. Methods. We used cross-sectional data from 1878 urban adolescents living in 38 neighborhoods who participated in the 2008 Boston Youth Survey, a biennial survey of high school students (aged 14–19 years). We used multilevel multiple regression models to determine the association between neighborhood-level exposures of economic deprivation, social fragmentation, social cohesion, danger and disorder, and students’ reports of no participation in physical activity in the previous week. Results. High social fragmentation within the residential neighborhood was associated with an increased likelihood of being inactive (odds ratio = 1.53; 95% confidence interval = 1.14, 2.05). No other neighborhood exposures were associated with physical inactivity. Conclusions. Social fragmentation might be an important correlate of physical inactivity among youths living in urban settings. Interventions might be needed to assist youths living in unstable neighborhoods to be physically active. PMID:25211727

Male perpetration of teen dating violence: associations with neighborhood violence involvement, gender attitudes, and perceived peer and neighborhood norms.

PubMed

Reed, Elizabeth; Silverman, Jay G; Raj, Anita; Decker, Michele R; Miller, Elizabeth

2011-04-01

This study aims to examine the link between male perpetration of teen dating violence (TDV) and neighborhood violence, as well as associations with gender attitudes and perceived peer and neighborhood norms related to violence among a sample of urban adolescent boys. Participants of this cross-sectional study (N = 275) were between the ages of 14 and 20 years and recruited from urban community health centers. Crude and adjusted logistic and linear regression models were used to examine TDV perpetration in relation to (a) neighborhood violence involvement, (b) perceptions of peer violence, (c) perceptions of neighborhood violence, and (d) gender attitudes. Slightly more than one in four (28%) boys reported at least one form of TDV perpetration; among boys who have ever had sex, almost half (45%) reported at least one form of TDV perpetration. In logistic and linear regression models adjusted for demographics, boys who reported TDV perpetration were more likely to report involvement in neighborhood violence (odds ratio (OR) = 3.1; 95% confidence interval (CI) = 1.7-5.5), beliefs that their friends have perpetrated TDV (OR = 2.7; 95%CI = 1.4-5.1), perceptions of violent activity within their neighborhood (OR = 3.0; 95%CI = 1.4-6.3), and greater support of traditional gender norms (β = 3.2, p = 0.002). The findings suggest that efforts are needed to address boys' behaviors related to the perpetration of multiple forms of violence and require explicit efforts to reduce perceived norms of violence perpetration as well as problematic gender attitudes (e.g., increasing support for gender equity) across boys' life contexts.

Surface Curvatures Computation from Equidistance Contours

NASA Astrophysics Data System (ADS)

Tanaka, Hiromi T.; Kling, Olivier; Lee, Daniel T. L.

1990-03-01

The subject of our research is on the 3D shape representation problem for a special class of range image, one where the natural mode of the acquired range data is in the form of equidistance contours, as exemplified by a moire interferometry range system. In this paper we present a novel surface curvature computation scheme that directly computes the surface curvatures (the principal curvatures, Gaussian curvature and mean curvature) from the equidistance contours without any explicit computations or implicit estimates of partial derivatives. We show how the special nature of the equidistance contours, specifically, the dense information of the surface curves in the 2D contour plane, turns into an advantage for the computation of the surface curvatures. The approach is based on using simple geometric construction to obtain the normal sections and the normal curvatures. This method is general and can be extended to any dense range image data. We show in details how this computation is formulated and give an analysis on the error bounds of the computation steps showing that the method is stable. Computation results on real equidistance range contours are also shown.

Associations of neighborhood social environment attributes and physical activity among 9-11 year old children from 12 countries.

PubMed

Sullivan, Samaah M; Broyles, Stephanie T; Barreira, Tiago V; Chaput, Jean-Philippe; Fogelholm, Mikael; Hu, Gang; Kuriyan, Rebecca; Kurpad, Anura; Lambert, Estelle V; Maher, Carol; Maia, Jose; Matsudo, Victor; Olds, Tim; Onywera, Vincent; Sarmiento, Olga L; Standage, Martyn; Tremblay, Mark S; Tudor-Locke, Catrine; Zhao, Pei; Katzmarzyk, Peter T

2017-07-01

We investigated whether associations of neighborhood social environment attributes and physical activity differed among 12 countries and levels of economic development using World Bank classification (low/lower-middle-, upper-middle- and high- income countries) among 9-11 year old children (N=6161) from the International Study of Childhood Obesity, Lifestyle, and the Environment (ISCOLE). Collective efficacy and perceived crime were obtained via parental/guardian report. Moderate-to-vigorous physical activity (MVPA) was assessed with waist-worn Actigraph accelerometers. Neighborhood environment by country interactions were tested using multi-level statistical models, adjusted for covariates. Effect estimates were reported by country and pooled estimates calculated across World Bank classifications for economic development using meta-analyses and forest plots. Associations between social environment attributes and MVPA varied among countries and levels of economic development. Associations were more consistent and in the hypothesized directions among countries with higher levels economic development, but less so among countries with lower levels of economic development. Copyright © 2017 Elsevier Ltd. All rights reserved.

Longitudinal effects of parental child and neighborhood factors on moderate vigorous physical activity and sedentary time in Latino children

USDA-ARS?s Scientific Manuscript database

Moderate-vigorous physical activity (%MVPA) confers beneficial effects on child musculoskeletal health, cardiovascular fitness, and psychosocial well-being; in contrast, sedentary time (%SED) is emerging as a risk factor for health. This study aimed to identify parental, child and neighborhood facto...

How much choice is there in housing choice vouchers? Neighborhood risk and free market rental housing accessibility for active drug users in Hartford, Connecticut.

PubMed

Dickson-Gomez, Julia B; Cromley, Ellen; Convey, Mark; Hilario, Helena

2009-04-15

Since the mid-1970s, the dominant model for U.S. federal housing policy has shifted from unit-based programs to tenant based vouchers and certificates, intended to allow recipients a choice in their housing and neighborhoods. Surprisingly little research has examined the question of where those with Section 8 housing vouchers are able to live, but some research suggests that voucher holders are more likely to reside in distressed neighborhoods than unsubsidized renter households. Further, federal housing policy has limited drug users' access to housing subsidies. In turn, neighborhood disorder has been associated with higher levels of injection drug risk behaviors, and higher drug-related mortality. This paper explores rental accessibility and neighborhood characteristics of advertised rental housing in Hartford CT. Brief telephone interviews were conducted with landlords or management companies with units to rent in Hartford to explore housing accessibility measured as initial move in costs, credit and criminal background checks, and whether rental subsidies were accepted. These data were supplemented with in-depth interviews with landlords, shelter staff and active users of heroin, crack or cocaine. Apartments for rent were geocoded and mapped using ArcGIS. We used location quotients to identify areas where low-income rental housing is concentrated. Finally, we mapped apartments in relation to drug and violent arrest rates in each neighborhood. High security deposits, criminal background and credit checks limit housing accessibility even for drug users receiving vouchers. While most landlords or management companies accepted housing subsidies, several did not. Voucher units are concentrated in neighborhoods with high poverty neighborhoods. Landlords reported little incentive to accept rental subsidies in neighborhoods with low crime rates, but appreciated the guarantee provided by Section 8 in high crime neighborhoods that were less likely to attract applicants

Interactive 3D segmentation using connected orthogonal contours.

PubMed

de Bruin, P W; Dercksen, V J; Post, F H; Vossepoel, A M; Streekstra, G J; Vos, F M

2005-05-01

This paper describes a new method for interactive segmentation that is based on cross-sectional design and 3D modelling. The method represents a 3D model by a set of connected contours that are planar and orthogonal. Planar contours overlayed on image data are easily manipulated and linked contours reduce the amount of user interaction.1 This method solves the contour-to-contour correspondence problem and can capture extrema of objects in a more flexible way than manual segmentation of a stack of 2D images. The resulting 3D model is guaranteed to be free of geometric and topological errors. We show that manual segmentation using connected orthogonal contours has great advantages over conventional manual segmentation. Furthermore, the method provides effective feedback and control for creating an initial model for, and control and steering of, (semi-)automatic segmentation methods.

Poor neighborhoods: safe playgrounds.

PubMed

Powell, Elizabeth C; Ambardekar, Erin J; Sheehan, Karen M

2005-09-01

Although unstructured physical play is helpful to child development and physical activity is important to obesity prevention, up-to-date information about playgrounds and playground hazards in urban areas is limited. Local data are needed to identify problems and target interventions. The aim of this study was to describe the hazards in playgrounds located in low-income (median dollars 28,728-38,915) and very low-income (median dollars 18,266-18,955) Chicago neighborhoods. Using a standardized on-site survey (National Program for Playground Safety), two investigators reviewed seventy-eight public playgrounds for hazards related to playground design, safe surfaces, supervision, and equipment design and maintenance. The design of 56 playgrounds (72%) posed no hazards. One playground lacked protection from motor vehicles, and 21 had minor flaws. One playground had an asphalt surface; all others had protective surfaces, usually wood chips. The chips were too thin in many places, and in 15 playgrounds (19%), at least one concrete footing was exposed. Trash was a common surface hazard (68%). Although most equipment was safe (swings of soft materials and appropriate platform barriers), many pieces needed repairs. Equipment maintenance hazards included gaps (44%) and missing (38%) or broken parts (35%). In 13 of 39 playgrounds (33%) where children were observed playing, one or more were unsupervised. Playgrounds in very low-income neighborhoods more often had trash in the fall zone and exposed footings (P<.01 for each); there were no differences between low and very low-income neighborhoods in playground design or equipment maintenance. We conclude that playgrounds in low-income Chicago neighborhoods are of good design and have appropriate surfaces. Needed improvements include attention to wood chip depth, the removal of trash from the fall zone, and equipment repairs. Greater adult supervision is warranted.

Details of Side Load Test Data and Analysis for a Truncated Ideal Contour Nozzle and a Parabolic Contour Nozzle

NASA Technical Reports Server (NTRS)

Ruf, Joseph H.; McDaniels, David M.; Brown, Andrew M.

2010-01-01

Two cold flow subscale nozzles were tested for side load characteristics during simulated nozzle start transients. The two test article contours were a truncated ideal and a parabolic. The current paper is an extension of a 2009 AIAA JPC paper on the test results for the same two nozzle test articles. The side load moments were measured with the strain tube approach in MSFC s Nozzle Test Facility. The processing techniques implemented to convert the strain gage signals into side load moment data are explained. Nozzle wall pressure profiles for separated nozzle flow at many NPRs are presented and discussed in detail. The effect of the test cell diffuser inlet on the parabolic nozzle s wall pressure profiles for separated flow is shown. The maximum measured side load moments for the two contours are compared. The truncated ideal contour s peak side load moment was 45% of that of the parabolic contour. The calculated side load moments, via mean-plus-three-standard-deviations at each nozzle pressure ratio, reproduced the characteristics and absolute values of measured maximums for both contours. The effect of facility vibration on the measured side load moments is quantified and the effect on uncertainty is calculated. The nozzle contour designs are discussed and the impact of a minor fabrication flaw in the nozzle contours is explained.

Negative Life Events Vary by Neighborhood and Mediate the Relation Between Neighborhood Context and Psychological Well-Being

EPA Science Inventory

Although a considerable amount of neighborhood research has addressed how fear of negative events may activate stress responses, few studies have noted the potentially embedded nature of negative life events within spatial riskscapes. Co-occurring contextual social and physical h...

Trajectories of Neighborhood Attainment after Prison

PubMed Central

Lee, Keun Bok; Harding, David J.; Morenoff, Jeffrey D.

2018-01-01

A potentially important but understudied aspect of prisoner reentry is the neighborhood environments experienced by formerly incarcerated people. We know that many formerly incarcerated people return to very disadvantaged neighborhood environments and that returning to disadvantaged neighborhoods after prison increases the risk of recidivism and reduces employment. Yet very little is known about the social, economic, and institutional processes that sort formerly incarcerated people into different neighborhoods after release or their trajectories of neighborhood attainment over time. Motivated by a conceptualization of prisoner reentry and reintegration as a process that unfolds over time, we examine trajectories of neighborhood environments after release. Motivated by the literatures on neighborhood attainment, social capital, and the role of criminal justice institutions in structuring the lives of former prisoners, we examine sources of variation in neighborhood attainment. We use administrative data from the Michigan Department of Corrections on formerly incarcerated people paroled in 2003 and followed for two years after release. Descriptive results from a latent class trajectory model show that most white and black formerly incarcerated people experience flat trajectories, with little upward or downward residential mobility over time. Findings from multi-level growth curve models suggest that institutional factors are particularly important for the neighborhood attainment of whites, while human capital and social ties are particularly important for blacks. Among both blacks and whites, pre-prison and first post-prison neighborhood conditions exhibit a strong association with post-prison neighborhood attainment, although these associations are larger for blacks than whites. PMID:28705357

Segmentation of lung fields using Chan-Vese active contour model in chest radiographs

NASA Astrophysics Data System (ADS)

Sohn, Kiwon

2011-03-01

A CAD tool for chest radiographs consists of several procedures and the very first step is segmentation of lung fields. We develop a novel methodology for segmentation of lung fields in chest radiographs that can satisfy the following two requirements. First, we aim to develop a segmentation method that does not need a training stage with manual estimation of anatomical features in a large training dataset of images. Secondly, for the ease of implementation, it is desirable to apply a well established model that is widely used for various image-partitioning practices. The Chan-Vese active contour model, which is based on Mumford-Shah functional in the level set framework, is applied for segmentation of lung fields. With the use of this model, segmentation of lung fields can be carried out without detailed prior knowledge on the radiographic anatomy of the chest, yet in some chest radiographs, the trachea regions are unfavorably segmented out in addition to the lung field contours. To eliminate artifacts from the trachea, we locate the upper end of the trachea, find a vertical center line of the trachea and delineate it, and then brighten the trachea region to make it less distinctive. The segmentation process is finalized by subsequent morphological operations. We randomly select 30 images from the Japanese Society of Radiological Technology image database to test the proposed methodology and the results are shown. We hope our segmentation technique can help to promote of CAD tools, especially for emerging chest radiographic imaging techniques such as dual energy radiography and chest tomosynthesis.

CT liver volumetry using geodesic active contour segmentation with a level-set algorithm

NASA Astrophysics Data System (ADS)

Suzuki, Kenji; Epstein, Mark L.; Kohlbrenner, Ryan; Obajuluwa, Ademola; Xu, Jianwu; Hori, Masatoshi; Baron, Richard

2010-03-01

Automatic liver segmentation on CT images is challenging because the liver often abuts other organs of a similar density. Our purpose was to develop an accurate automated liver segmentation scheme for measuring liver volumes. We developed an automated volumetry scheme for the liver in CT based on a 5 step schema. First, an anisotropic smoothing filter was applied to portal-venous phase CT images to remove noise while preserving the liver structure, followed by an edge enhancer to enhance the liver boundary. By using the boundary-enhanced image as a speed function, a fastmarching algorithm generated an initial surface that roughly estimated the liver shape. A geodesic-active-contour segmentation algorithm coupled with level-set contour-evolution refined the initial surface so as to more precisely fit the liver boundary. The liver volume was calculated based on the refined liver surface. Hepatic CT scans of eighteen prospective liver donors were obtained under a liver transplant protocol with a multi-detector CT system. Automated liver volumes obtained were compared with those manually traced by a radiologist, used as "gold standard." The mean liver volume obtained with our scheme was 1,520 cc, whereas the mean manual volume was 1,486 cc, with the mean absolute difference of 104 cc (7.0%). CT liver volumetrics based on an automated scheme agreed excellently with "goldstandard" manual volumetrics (intra-class correlation coefficient was 0.95) with no statistically significant difference (p(F<=f)=0.32), and required substantially less completion time. Our automated scheme provides an efficient and accurate way of measuring liver volumes.

Breast masses in mammography classification with local contour features.

PubMed

Li, Haixia; Meng, Xianjing; Wang, Tingwen; Tang, Yuchun; Yin, Yilong

2017-04-14

Mammography is one of the most popular tools for early detection of breast cancer. Contour of breast mass in mammography is very important information to distinguish benign and malignant mass. Contour of benign mass is smooth and round or oval, while malignant mass has irregular shape and spiculated contour. Several studies have shown that 1D signature translated from 2D contour can describe the contour features well. In this paper, we propose a new method to translate 2D contour of breast mass in mammography into 1D signature. The method can describe not only the contour features but also the regularity of breast mass. Then we segment the whole 1D signature into different subsections. We extract four local features including a new contour descriptor from the subsections. The new contour descriptor is root mean square (RMS) slope. It can describe the roughness of the contour. KNN, SVM and ANN classifier are used to classify benign breast mass and malignant mass. The proposed method is tested on a set with 323 contours including 143 benign masses and 180 malignant ones from digital database of screening mammography (DDSM). The best accuracy of classification is 99.66% using the feature of root mean square slope with SVM classifier. The performance of the proposed method is better than traditional method. In addition, RMS slope is an effective feature comparable to most of the existing features.

Segmenting breast cancerous regions in thermal images using fuzzy active contours

PubMed Central

Ghayoumi Zadeh, Hossein; Haddadnia, Javad; Rahmani Seryasat, Omid; Mostafavi Isfahani, Sayed Mohammad

2016-01-01

Breast cancer is the main cause of death among young women in developing countries. The human body temperature carries critical medical information related to the overall body status. Abnormal rise in total and regional body temperature is a natural symptom in diagnosing many diseases. Thermal imaging (Thermography) utilizes infrared beams which are fast, non-invasive, and non-contact and the output created images by this technique are flexible and useful to monitor the temperature of the human body. In some clinical studies and biopsy tests, it is necessary for the clinician to know the extent of the cancerous area. In such cases, the thermal image is very useful. In the same line, to detect the cancerous tissue core, thermal imaging is beneficial. This paper presents a fully automated approach to detect the thermal edge and core of the cancerous area in thermography images. In order to evaluate the proposed method, 60 patients with an average age of 44/9 were chosen. These cases were suspected of breast tissue disease. These patients referred to Tehran Imam Khomeini Imaging Center. Clinical examinations such as ultrasound, biopsy, questionnaire, and eventually thermography were done precisely on these individuals. Finally, the proposed model is applied for segmenting the proved abnormal area in thermal images. The proposed model is based on a fuzzy active contour designed by fuzzy logic. The presented method can segment cancerous tissue areas from its borders in thermal images of the breast area. In order to evaluate the proposed algorithm, Hausdorff and mean distance between manual and automatic method were used. Estimation of distance was conducted to accurately separate the thermal core and edge. Hausdorff distance between the proposed and the manual method for thermal core and edge was 0.4719 ± 0.4389, 0.3171 ± 0.1056 mm respectively, and the average distance between the proposed and the manual method for core and thermal edge was 0.0845 ± 0.0619, 0.0710 �

Nonprofit Housing and Neighborhood Spillovers

ERIC Educational Resources Information Center

Ellen, Ingrid Gould; Voicu, Ioan

2006-01-01

Nonprofit organizations play a critical role in U.S. housing policy, a role typically justified by the claim that their housing investments produce significant neighbor-hood spillover benefits. However, little work has actually been done to measure these impacts on neighborhoods. This paper compares the neighborhood spillover effects of…

Impact of contour on aesthetic judgments and approach-avoidance decisions in architecture

PubMed Central

Vartanian, Oshin; Navarrete, Gorka; Chatterjee, Anjan; Fich, Lars Brorson; Leder, Helmut; Modroño, Cristián; Nadal, Marcos; Rostrup, Nicolai; Skov, Martin

2013-01-01

On average, we urban dwellers spend about 90% of our time indoors, and share the intuition that the physical features of the places we live and work in influence how we feel and act. However, there is surprisingly little research on how architecture impacts behavior, much less on how it influences brain function. To begin closing this gap, we conducted a functional magnetic resonance imaging study to examine how systematic variation in contour impacts aesthetic judgments and approach-avoidance decisions, outcome measures of interest to both architects and users of spaces alike. As predicted, participants were more likely to judge spaces as beautiful if they were curvilinear than rectilinear. Neuroanatomically, when contemplating beauty, curvilinear contour activated the anterior cingulate cortex exclusively, a region strongly responsive to the reward properties and emotional salience of objects. Complementing this finding, pleasantness—the valence dimension of the affect circumplex—accounted for nearly 60% of the variance in beauty ratings. Furthermore, activation in a distributed brain network known to underlie the aesthetic evaluation of different types of visual stimuli covaried with beauty ratings. In contrast, contour did not affect approach-avoidance decisions, although curvilinear spaces activated the visual cortex. The results suggest that the well-established effect of contour on aesthetic preference can be extended to architecture. Furthermore, the combination of our behavioral and neural evidence underscores the role of emotion in our preference for curvilinear objects in this domain. PMID:23754408

Neighborhood Environment and Cognition in Older Adults: A Systematic Review.

PubMed

Besser, Lilah M; McDonald, Noreen C; Song, Yan; Kukull, Walter A; Rodriguez, Daniel A

2017-08-01

Some evidence suggests that treating vascular risk factors and performing mentally stimulating activities may delay cognitive impairment onset in older adults. Exposure to a complex neighborhood environment may be one mechanism to help delay cognitive decline. PubMed, Web of Science, and ProQuest Dissertation and Theses Global database were systematically reviewed, identifying 25 studies published from February 1, 1989 to March 5, 2016 (data synthesized, May 3, 2015 to October 7, 2016). The review was restricted to quantitative studies focused on: (1) neighborhood social and built environment and cognition; and (2) community-dwelling adults aged ≥45 years. The majority of studies were cross-sectional, U.S.-based, and found at least one significant association. The diversity of measures and neighborhood definitions limited the synthesis of findings in many instances. Evidence was moderately strong for an association between neighborhood SES and cognition, and modest for associations between neighborhood demographics, design, and destination accessibility and cognition. Most studies examining effect modification found significant associations, with some evidence for effect modification of the neighborhood SES-cognition association by individual-level SES. No studies had low risk of bias and many tested multiple associations that increased the chance of a statistically significant finding. Considering the studies to date, the evidence for an association between neighborhood characteristics and cognition is modest. Future studies should include longitudinal measures of neighborhood characteristics and cognition; examine potential effect modifiers, such as sex and disability; and study mediators that may help elucidate the biological mechanisms linking neighborhood environment and cognition. Copyright © 2017 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

Perceived School and Neighborhood Safety, Neighborhood Violence and Academic Achievement in Urban School Children

PubMed Central

AJ, Milam; CDM, Furr-Holden; PJ, Leaf

2010-01-01

Community and school violence continue to be a major public health problem, especially among urban children and adolescents. Little research has focused on the effect of school safety and neighborhood violence on academic performance. This study examines the effect of the school and neighborhood climate on academic achievement among a population of 3rd-5th grade students in an urban public school system. Community and school safety were assessed using the School Climate Survey, an annual city-wide assessment of student’s perception of school and community safety. Community violence was measured using the Neighborhood Inventory for Environmental Typology, an objective observational assessment of neighborhood characteristics. Academic achievement was measured using the Maryland State Assessment (MSA), a standardized exam given to all Maryland 3rd-8th graders. School Climate Data and MSA data were aggregated by school and grade. Objective assessments of neighborhood environment and students’ self-reported school and neighborhood safety were both strongly associated with academic performance. Increasing neighborhood violence was associated with statistically significant decreases from 4.2%-8.7% in math and reading achievement; increasing perceived safety was associated with significant increases in achievement from 16%-22%. These preliminary findings highlight the adverse impact of perceived safety and community violence exposure on primary school children’s academic performance. PMID:21197388

The effect of neighborhood-based community organizing: results from the Seattle Minority Youth Health Project.

PubMed

Cheadle, A; Wagner, E; Walls, M; Diehr, P; Bell, M; Anderman, C; McBride, C; Catalano, R F; Pettigrew, E; Simmons, R; Neckerman, H

2001-08-01

To evaluate the effect of a community mobilization and youth development strategy to prevent drug abuse, violence, and risky sexual activity. Primary surveys of youth, parents, and key neighborhood leaders were carried out at baseline (1994) and at the end of the intervention period (1997). The study took place in four intervention and six control neighborhoods in Seattle. The study was designed as a randomized controlled trial with neighborhood as the unit of randomization. The intervention consisted of a paid community organizer in each neighborhood who recruited a group of residents to serve as a community action board. Key variables included perceptions of neighborhood mobilization by youth, parents, and key neighborhood leaders. Youth surveys were self-administered during school hours. Parent and neighborhood leader surveys were conducted over the phone by trained interviewers. Survey results showed that mobilization increased to the same degree in both intervention and control neighborhoods with no evidence of an overall intervention effect. There did appear to be a relative increase in mobilization in the neighborhood with the highest level of intervention activity. This randomized study failed to demonstrate a measurable effect for a community mobilization intervention. It is uncertain whether the negative finding was because of a lack of strength of the interventions or problems detecting intervention effects using individual-level closed-end surveys.

Longitudinal relations of perceived availability of neighborhood sport facilities with physical activity in adolescents: an analysis of potential moderators.

PubMed

Wong, Bonny Yee-Man; Ho, Sai-Yin; Lo, Wing-Sze; Cerin, Ester; Mak, Kwok-Kei; Lam, Tai-Hing

2014-03-01

Little is known about the longitudinal relations of environment attributes and leisure-time physical activity (PA) in adolescents, and the moderating effects of individual characteristics. This study examined the longitudinal association of the perceived availability of neighborhood sport facilities with leisure-time PA, and the potential moderating effects of age, past PA behavior, and weight status in adolescents. Among 20,933 follow-up subjects (60.9% of 34,369 baseline subjects), 9993 from 32 Hong Kong secondary schools were successfully matched with baseline (mean duration 16 months; SD 1.7) and had complete information. At baseline and follow-up, respondents reported their leisure-time PA, weight, height, and the presence of sport facilities in the neighborhood. Increased perceived availability of sport facilities from baseline to follow-up predicted more leisure-time PA at follow-up (β = 1.029; 95% CI: 1.0111.047) overall. This effect was modified by baseline PA, with a significant effect observed only among those who had engaged in leisure-time PA more than 3 times a week. Increasing awareness of neighborhood sport facilities or building more such facilities may help active adolescents maintain or increase their leisure-time PA. However, more comprehensive multilevel interventions that aim at enhancing potential social, personal, and environmental PA-related factors may be needed to motivate inactive adolescents.

Efficient hyperspectral image segmentation using geometric active contour formulation

NASA Astrophysics Data System (ADS)

Albalooshi, Fatema A.; Sidike, Paheding; Asari, Vijayan K.

2014-10-01

In this paper, we present a new formulation of geometric active contours that embeds the local hyperspectral image information for an accurate object region and boundary extraction. We exploit self-organizing map (SOM) unsupervised neural network to train our model. The segmentation process is achieved by the construction of a level set cost functional, in which, the dynamic variable is the best matching unit (BMU) coming from SOM map. In addition, we use Gaussian filtering to discipline the deviation of the level set functional from a signed distance function and this actually helps to get rid of the re-initialization step that is computationally expensive. By using the properties of the collective computational ability and energy convergence capability of the active control models (ACM) energy functional, our method optimizes the geometric ACM energy functional with lower computational time and smoother level set function. The proposed algorithm starts with feature extraction from raw hyperspectral images. In this step, the principal component analysis (PCA) transformation is employed, and this actually helps in reducing dimensionality and selecting best sets of the significant spectral bands. Then the modified geometric level set functional based ACM is applied on the optimal number of spectral bands determined by the PCA. By introducing local significant spectral band information, our proposed method is capable to force the level set functional to be close to a signed distance function, and therefore considerably remove the need of the expensive re-initialization procedure. To verify the effectiveness of the proposed technique, we use real-life hyperspectral images and test our algorithm in varying textural regions. This framework can be easily adapted to different applications for object segmentation in aerial hyperspectral imagery.

Who Gentrifies Low-Income Neighborhoods?

PubMed

McKinnish, Terra; Walsh, Randall; White, T Kirk

2010-03-01

This paper uses confidential Census data, specifically the 1990 and 2000 Census Long Form data, to study demographic processes in neighborhoods that gentrified during the 1990's. In contrast to previous studies, the analysis is conducted at the more refined census-tract level, with a narrower definition of gentrification and more closely matched comparison neighborhoods. Furthermore, our access to individual-level data with census tract identifiers allows us to separately identify recent in-migrants and long-term residents. Our results indicate that, on average, the demographic flows associated with the gentrification of urban neighborhoods during the 1990's are not consistent with displacement and harm to minority households. In fact, taken as a whole, our results suggest that gentrification of predominantly black neighborhoods creates neighborhoods that are attractive to middle-class black households.

Neighborhood-Specific and General Social Support: Which Buffers the Effect of Neighborhood Disorder on Depression?

ERIC Educational Resources Information Center

Kim, Joongbaeck; Ross, Catherine E.

2009-01-01

Is neighborhood-specific social support the most effective type of social support for buffering the effect of neighborhood disorder on depression? Matching theory suggests that it is. The authors extend the research on neighborhood disorder and adult depression by showing that individuals who have higher levels of both general and…

Automated segmentation of ultrasonic breast lesions using statistical texture classification and active contour based on probability distance.

PubMed

Liu, Bo; Cheng, H D; Huang, Jianhua; Tian, Jiawei; Liu, Jiafeng; Tang, Xianglong

2009-08-01

Because of its complicated structure, low signal/noise ratio, low contrast and blurry boundaries, fully automated segmentation of a breast ultrasound (BUS) image is a difficult task. In this paper, a novel segmentation method for BUS images without human intervention is proposed. Unlike most published approaches, the proposed method handles the segmentation problem by using a two-step strategy: ROI generation and ROI segmentation. First, a well-trained texture classifier categorizes the tissues into different classes, and the background knowledge rules are used for selecting the regions of interest (ROIs) from them. Second, a novel probability distance-based active contour model is applied for segmenting the ROIs and finding the accurate positions of the breast tumors. The active contour model combines both global statistical information and local edge information, using a level set approach. The proposed segmentation method was performed on 103 BUS images (48 benign and 55 malignant). To validate the performance, the results were compared with the corresponding tumor regions marked by an experienced radiologist. Three error metrics, true-positive ratio (TP), false-negative ratio (FN) and false-positive ratio (FP) were used for measuring the performance of the proposed method. The final results (TP = 91.31%, FN = 8.69% and FP = 7.26%) demonstrate that the proposed method can segment BUS images efficiently, quickly and automatically.

Improving Mental Health Through the Regeneration of Deprived Neighborhoods: A Natural Experiment.