Showing papers by "San Diego State University published in 2006"

An ecological approach to creating active living communities.

Abstract: ▪ Abstract The thesis of this article is that multilevel interventions based on ecological models and targeting individuals, social environments, physical environments, and policies must be implemented to achieve population change in physical activity. A model is proposed that identifies potential environmental and policy influences on four domains of active living: recreation, transport, occupation, and household. Multilevel research and interventions require multiple disciplines to combine concepts and methods to create new transdisciplinary approaches. The contributions being made by a broad range of disciplines are summarized. Research to date supports a conclusion that there are multiple levels of influence on physical activity, and the active living domains are associated with different environmental variables. Continued research is needed to provide detailed findings that can inform improved designs of communities, transportation systems, and recreation facilities. Collaborations with policy resear...

Many Pathways from Land Use to Health: Associations between Neighborhood Walkability and Active Transportation, Body Mass Index, and Air Quality

Abstract: The literature shows single-use, low-density land development and disconnected street networks to be positively associated with auto dependence and negatively associated with walking and transit use. These factors in turn appear to affect health by influencing physical activity, obesity, and emissions of air pollutants. We evaluated the association between a single index of walkability that incorporated land use mix, street connectivity, net residential density, and retail floor area ratios, with health-related outcomes in King County, Washington. We found a 5% increase in walkability to be associated with a per capita 32.1% increase in time spent in physically active travel, a 0.23-point reduction in body mass index, 6.5% fewer vehicle miles traveled, 5.6% fewer grams of oxides of nitrogen (NOx) emitted, and 5.5% fewer grams of volatile organic compounds (VOC) emitted. These results connect development patterns with factors that affect several prevalent chronic diseases.

Generation Me: Why Today's Young Americans Are More Confident, Assertive, Entitled--and More Miserable Than Ever Before

Abstract: The Associated Press calls them 'the entitlement generation', and they are storming into schools, colleges, and businesses all over the country. They are today's young people, a new generation with sky-high expectations and a need for constant praise and fulfillment. In this provocative new book, headline-making psychologist and social commentator Dr. Jean Twenge documents the self-focus of what she calls 'Generation Me' -- people born in the 1970s, 1980s, and 1990s. Herself a member of Generation Me, Dr. Twenge explores why her generation is tolerant, confident, open-minded, and ambitious but also cynical, depressed, lonely, and anxious. Using findings from the largest intergenerational study ever conducted -- with data from 1.3 million respondents spanning six decades -- Dr. Twenge reveals how profoundly different today's young adults are -- and makes controversial predictions about what the future holds for them and society as a whole. But Dr. Twenge doesn't just talk statistics -- she highlights real-life people and stories and vividly brings to life the hopes and dreams, disappointments and challenges of Generation Me. With a good deal of irony, humor, and sympathy she demonstrates that today's young people have been raised to aim for the stars at a time when it is more difficult than ever to get into college, find a good job, and afford a house -- even with two incomes. GenMe's expectations have been raised just as the world is becoming more competitive, creating an enormous clash between expectations and reality. Dr. Twenge also presents the often-shocking truths about her generation's dramatically different sexual behavior and mores. GenMe has created a profound shift in the American character, changing what it means to be an individual in today's society. Engaging, controversial, prescriptive, and often funny, Generation Me will give Boomers new insight into their offspring, and help GenMe'ers in their teens, 20s, and 30s finally make sense of themselves and their goals and find their road to happiness.

The marine viromes of four oceanic regions

Abstract: Viruses are the most common biological entities in the marine environment. There has not been a global survey of these viruses, and consequently, it is not known what types of viruses are in Earth's oceans or how they are distributed. Metagenomic analyses of 184 viral assemblages collected over a decade and representing 68 sites in four major oceanic regions showed that most of the viral sequences were not similar to those in the current databases. There was a distinct “marine-ness” quality to the viral assemblages. Global diversity was very high, presumably several hundred thousand of species, and regional richness varied on a North-South latitudinal gradient. The marine regions had different assemblages of viruses. Cyanophages and a newly discovered clade of single-stranded DNA phages dominated the Sargasso Sea sample, whereas prophage-like sequences were most common in the Arctic. However most viral species were found to be widespread. With a majority of shared species between oceanic regions, most of the differences between viral assemblages seemed to be explained by variation in the occurrence of the most common viral species and not by exclusion of different viral genomes. These results support the idea that viruses are widely dispersed and that local environmental conditions enrich for certain viral types through selective pressure.

The role of built environments in physical activity, eating, and obesity in childhood

Abstract: Summary Over the past forty years various changes in the U.S. “built environment” have promoted sedentary lifestyles and less healthful diets. James Sallis and Karen Glanz investigate whether these changes have had a direct effect on childhood obesity and whether improvements to encourage more physical activity and more healthful diets are likely to lower rates of childhood obesity. Researchers, say Sallis and Glanz, have found many links between the built environment and children’s physical activity, but they have yet to find conclusive evidence that aspects of the built environment promote obesity. For example, certain development patterns, such as a lack of sidewalks, long distances to schools, and the need to cross busy streets, discourage walking and biking to school. Eliminating such barriers can increase rates of active commuting. But researchers cannot yet prove that more active commuting would reduce rates of obesity. Sallis and Glanz note that recent changes in the nutrition environment, including greater reliance on convenience foods and fast foods, a lack of access to fruits and vegetables, and expanding portion sizes, are also widely believed to contribute to the epidemic of childhood obesity. But again, conclusive evidence that changes in the nutrition environment will reduce rates of obesity does not yet exist. Research into the link between the built environment and childhood obesity is still in its infancy. Analysts do not know whether changes in the built environment have increased rates of obesity or whether improvements to the built environment will decrease them. Nevertheless, say Sallis and Glanz, the policy implications are clear. People who have access to safe places to be active, neighborhoods that are walkable, and local markets that offer healthful food are likely to be more active and to eat more healthful food—two types of behavior that can lead to good health and may help avoid obesity.

Attitudes and persuasion.

Abstract: Study of attitudes and persuasion remains a defining characteristic of contemporary social psychology. This review outlines recent advances, with emphasis on the relevance of today's work for perennial issues. We reiterate the distinction between attitude formation and change, and show its relevance for persuasion. Single- and dual-process models are discussed, as are current views on dissonance theory. Majority and minority influence are scrutinized, with special emphasis on integrative theoretical innovations. Attitude strength is considered, and its relevance to ambivalence and resistance documented. Affect, mood, and emotion effects are reviewed, especially as they pertain to fear arousal and (un)certainty. Finally, we discuss attitude-behavior consistency, perhaps the reason for our interest in attitudes in the first place, with emphasis on self-interest and the theory of planned behavior. Our review reflects the dynamism and the reach of the area, and suggests a sure and sometimes rapid accumulation of knowledge and understanding.

Neighborhood Environment Walkability Scale: Validity and Development of a Short Form

Abstract: Purpose:The aim of this study was to examine the factorial and criterion validity of the Neighborhood Environment Walkability Scale (NEWS) and to develop an abbreviated version (NEWS-A).Methods:A stratified two-stage cluster sample design was used to recruit 1286 adults. The sample was drawn

Social and Economic Exchange: Construct Development and Validation.

Abstract: This study examined the economic and social exchanges between employee and employer within a model in which perceived organizational support and affective and continuance commitment served as predictors and performance, altruism citizenship behavior, absence, and lateness served as outcomes. Two samples were used. 384 master of business administration students participated in Study 1, and Study 2 consisted of 181 aerospace employees and their managers, working for a single organization. Both studies supported the distinctiveness between economic and social exchanges. Study 2 showed the overall fit of the proposed model was adequate, though only social exchange, and not economic exchange, directly predicted the performance outcomes. These results suggest the importance of perceived exchanges between employee and employer.

Evaluation of remote sensing based terrestrial productivity from MODIS using regional tower eddy flux network observations

Abstract: The Moderate Resolution Spectroradiometer (MODIS) sensor has provided near real-time estimates of gross primary production (GPP) since March 2000. We compare four years (2000 to 2003) of satellite-based calculations of GPP with tower eddy CO2 flux-based estimates across diverse land cover types and climate regimes. We examine the potential error contributions from meteorology, leaf area index (LAI)/fPAR, and land cover. The error between annual GPP computed from NASA's Data Assimilation Office's (DAO) and tower-based meteorology is 28%, indicating that NASA's DAO global meteorology plays an important role in the accuracy of the GPP algorithm. Approximately 62% of MOD15-based estimates of LAI were within the estimates based on field optical measurements, although remaining values overestimated site values. Land cover presented the fewest errors, with most errors within the forest classes, reducing potential error. Tower-based and MODIS estimates of annual GPP compare favorably for most biomes, although MODIS GPP overestimates tower-based calculations by 20%-30%. Seasonally, summer estimates of MODIS GPP are closest to tower data, and spring estimates are the worst, most likely the result of the relatively rapid onset of leaf-out. The results of this study indicate, however, that the current MODIS GPP algorithm shows reasonable spatial patterns and temporal variability across a diverse range of biomes and climate regimes. So, while continued efforts are needed to isolate particular problems in specific biomes, we are optimistic about the general quality of these data, and continuation of the MOD17 GPP product will likely provide a key component of global terrestrial ecosystem analysis, providing continuous weekly measurements of global vegetation production

Interpersonal Rejection as a Determinant of Anger and Aggression

Abstract: This article reviews the literature on the relationship between interpersonal rejection and aggression. Four bodies of research are summarized: laboratory experiments that manipulate rejection, rejection among adults in everyday life, rejection in childhood, and individual differences that may moderate the relationship. The theoretical mechanisms behind the effect are then explored. Possible explanations for why rejection leads to anger and aggression include: rejection as a source of pain, rejection as a source of frustration, rejection as a threat to self-esteem, mood improvement following aggression, aggression as social influence, aggression as a means of reestablishing control, retribution, disinhibition, and loss of self-control.

Active Commuting to School: Associations with Environment and Parental Concerns

Abstract: Purpose: This study examined the association of objective and perceived neighborhood environmental characteristics and parent concerns with active commuting to school, investigated whether parental concerns varied by environmental characteristics, and compared the association of the perceived environment, parental concerns, and objective environment on the outcome active commuting to school. Methods: Randomly selected parents of children (aged 5-18 yr), in neighborhoods chosen for their variability in objectively measured walkability and income, completed questionnaires about their neighborhood environment, concerns about children walking to school, and children's behavior (N = 259). Objective measures of the environment were available for each participant and each neighborhood. Logistic regression analyses were used to investigate the relationships among environment, parental concerns, and walking or biking to or from school at least once a week. Results: A parental concerns scale was most strongly associated with child active commuting (odds ratio: 5.2, 95% CI: 2.71-9.96). In high-income neighborhoods, more children actively commuted in high-walkable (34%) than in low-walkable neighborhoods (23%) (odds ratio: 2.1, 95% CI: 1.12-3.97), but no differences were noted in low-income neighborhoods. Parent concerns and neighborhood aesthetics were independently associated with active commuting. Perceived access to local stores and biking or walking facilities accounted for some of the effect of walkability on active commuting. Conclusion: Both parent concerns and the built environment were associated with children's active commuting to school. To increase active commuting to school, interventions that include both environmental change and education campaigns may be needed.

Winter forest soil respiration controlled by climate and microbial community composition

Abstract: Most terrestrial carbon sequestration at mid-latitudes in the Northern Hemisphere occurs in seasonal, montane forest ecosystems. Winter respiratory carbon dioxide losses from these ecosystems are high, and over half of the carbon assimilated by photosynthesis in the summer can be lost the following winter. The amount of winter carbon dioxide loss is potentially susceptible to changes in the depth of the snowpack; a shallower snowpack has less insulation potential, causing colder soil temperatures and potentially lower soil respiration rates. Recent climate analyses have shown widespread declines in the winter snowpack of mountain ecosystems in the western USA and Europe that are coupled to positive temperature anomalies. Here we study the effect of changes in snow cover on soil carbon cycling within the context of natural climate variation. We use a six-year record of net ecosystem carbon dioxide exchange in a subalpine forest to show that years with a reduced winter snowpack are accompanied by significantly lower rates of soil respiration. Furthermore, we show that the cause of the high sensitivity of soil respiration rate to changes in snow depth is a unique soil microbial community that exhibits exponential growth and high rates of substrate utilization at the cold temperatures that exist beneath the snow. Our observations suggest that a warmer climate may change soil carbon sequestration rates in forest ecosystems owing to changes in the depth of the insulating snow cover.

Using pyrosequencing to shed light on deep mine microbial ecology.

Abstract: Contrasting biological, chemical and hydrogeological analyses highlights the fundamental processes that shape different environments. Generating and interpreting the biological sequence data was a costly and time-consuming process in defining an environment. Here we have used pyrosequencing, a rapid and relatively inexpensive sequencing technology, to generate environmental genome sequences from two sites in the Soudan Mine, Minnesota, USA. These sites were adjacent to each other, but differed significantly in chemistry and hydrogeology. Comparisons of the microbes and the subsystems identified in the two samples highlighted important differences in metabolic potential in each environment. The microbes were performing distinct biochemistry on the available substrates, and subsystems such as carbon utilization, iron acquisition mechanisms, nitrogen assimilation, and respiratory pathways separated the two communities. Although the correlation between much of the microbial metabolism occurring and the geochemical conditions from which the samples were isolated could be explained, the reason for the presence of many pathways in these environments remains to be determined. Despite being physically close, these two communities were markedly different from each other. In addition, the communities were also completely different from other microbial communities sequenced to date. We anticipate that pyrosequencing will be widely used to sequence environmental samples because of the speed, cost, and technical advantages. Furthermore, subsystem comparisons rapidly identify the important metabolisms employed by the microbes in different environments.

Public Parks and Physical Activity Among Adolescent Girls

Abstract: OBJECTIVES.Physical activity may be constrained or facilitated by local environments. The availability of neighborhood facilities for physical activity may be particularly relevant for youth, who are unable to drive and whose activity is often limited to the immediate distance they are able to walk or bicycle. Several studies have shown that proximity to recreational facilities and parks is one of the most important predictors of physical activity. Because the United States already has an extensive infrastructure of parks, with 70% of adults indicating that they live within walking distance of a park or playground, parks may be a potential venue for increasing physical activity. This might be particularly important for adolescent girls, whose physical activity levels decline substantially as they go through puberty. The goal of this study was to examine the association between park proximity, park type, and park features and physical activity in adolescent girls. PATIENTS AND METHODS.This was a cross-sectional study using baseline data from the Trial of Activity for Adolescent Girls. It included 1556 grade 6 girls who were randomly selected from 6 middle schools in each of the following 6 field site areas: Washington, DC, and Baltimore, Maryland; Columbia, South Carolina; Minneapolis, Minnesota; New Orleans, Louisiana; Tucson, Arizona; and San Diego, California. Girls wore accelerometers for 6 days to measure metabolic equivalent‐ weighted moderate-to-vigorous physical activity, a measure accounting for the volume and intensity of activity. Metabolic equivalent‐weighted moderate-tovigorous physical activity was calculated for the hours outside of school time using 2 different cutpoints, activity levels 3.0 metabolic equivalents and 4.6 metabolic equivalents, the latter indicating activity at the intensity of a brisk walk or higher. We mapped all of the parks within 1 mile of each girl’s home. Trained staff used a checklist to document the presence of facilities and amenities at each park, including passive amenities, such as drinking fountains, restrooms, and areas with shade, as well as active amenities like basketball courts, multipurpose fields, playgrounds, and tennis courts.

Indirect effects of algae on coral: algae-mediated, microbe-induced coral mortality.

Abstract: Declines in coral cover are generally associated with increases in the abundance of fleshy algae. In many cases, it remains unclear whether algae are responsible, directly or indirectly, for coral death or whether they simply settle on dead coral surfaces. Here, we show that algae can indirectly cause coral mortality by enhancing microbial activity via the release of dissolved compounds. When coral and algae were placed in chambers together but separated by a 0.02 lm filter, corals suffered 100% mortality. With the addition of the broad-spectrum antibiotic ampicillin, mortality was completely prevented. Physiological measurements showed complementary patterns of increasing coral stress with proximity to algae. Our results suggest that as human impacts increase and algae become more abundant on reefs a positive feedback loop may be created whereby compounds released by algae enhance microbial activity on live coral surfaces causing mortality of corals and further algal growth.

System for Observing Play and Recreation in Communities (SOPARC): Reliability and Feasibility Measures

Abstract: Background: New tools are needed to examine physical activity and the contexts in which it occurs. Community parks contribute to physical activity, but measuring activity and associated variables in them is challenging because area contexts change and the numbers and characteristics of users are highly variable. Methods: We developed SOPARC (System for Observing Play and Recreation in Communities) and tested its use by observing 16,244 individuals in 165 park areas. Reliabilities included 472 simultaneous measures by independent observers. Results: Correlations between observers on number of area participants was 0.99 for female and male park users. Reliabilities (i.e., percent agreement) for age (89%, females; 85%, males), race/ethnic (80%, females; 82%, males), and activity level (80%, females; 88%, males) groupings met acceptable criteria. Reliabilities for area contexts (i.e., usable, accessible, supervised, organized, equipped) exceeded 94%. Conclusions: SOPARC is a reliable and feasible instrument for assessing physical activity and associated contextual data in community settings.

Evolutionary and Ecological Causes of the Latitudinal Diversity Gradient in Hylid Frogs: Treefrog Trees Unearth the Roots of High Tropical Diversity

Abstract: Why are there more species in the tropics than in temperate regions? In recent years, this long-standing question has been addressed primarily by seeking environmental correlates of diversity. But to understand the ultimate causes of diversity patterns, we must also examine the evolutionary and biogeographic processes that directly change species numbers (i.e., speciation, extinction, and dispersal). With this perspective, we dissect the latitudinal diversity gradient in hylid frogs. We reconstruct a phylogeny for 124 hylid species, estimate divergence times and diversification rates for major clades, reconstruct biogeographic changes, and use ecological niche modeling to identify climatic variables that potentially limit dispersal. We find that hylids originated in tropical South America and spread to temperate regions only recently (leaving limited time for speciation). There is a strong relationship between the species richness of each region and when that region was colonized but not between the latitudinal positions of clades and their rates of diversification. Temperature seasonality seemingly limits dispersal of many tropical clades into temperate regions and shows significant phylogenetic conservatism. Overall, our study illustrates how two general principles (niche conservatism and the time-for-speciation effect) may help explain the latitudinal diversity gradient as well as many other diversity patterns across taxa and regions.

A novel explosive process is required for the γ-ray burst GRB 060614

Abstract: Over the past decade, our physical understanding of gamma-ray bursts (GRBs) has progressed rapidly, thanks to the discovery and observation of their long-lived afterglow emission. Long-duration (≳2 s) GRBs are associated with the explosive deaths of massive stars ('collapsars', ref. 1), which produce accompanying supernovae; the short-duration (≲2 s) GRBs have a different origin, which has been argued to be the merger of two compact objects. Here we report optical observations of GRB 060614 (duration ~100 s, ref. 10) that rule out the presence of an associated supernova. This would seem to require a new explosive process: either a massive collapsar that powers a GRB without any associated supernova, or a new type of 'engine', as long-lived as the collapsar but without a massive star. We also show that the properties of the host galaxy (redshift z = 0.125) distinguish it from other long-duration GRB hosts and suggest that an entirely new type of GRB progenitor may be required.

Is parenting style related to children's healthy eating and physical activity in Latino families?

Abstract: Parenting styles influence a child’s risk forobesity. Thegoalsofthisstudyaretoevaluatetheinfluence of(i)parentingstyleonchildren’shealthbehaviors (physical activity and dietary intake), (ii) children’s sociodemographic characteristics on parenting style and on children’s health behaviors and (iii) parents’ sociodemographic characteristics on their use of controlling styles to promote a healthy home environment. Survey and anthropometric data were collected from a community sample of Latino parents (n 5 812) and their children in kindergarten through second grade. Parental use of positive reinforcement and monitoring was associated with children’s healthy eating and exercise. Also, parents’ use of appropriate disciplining styles was associated with healthier eating, while parental use of control styles was associated with unhealthy eating. The daughters of parents who used controlling styles ate more unhealthy foodsthandidthesons.Older,employedandmore acculturated parents used less controlling styles than their counterparts. Parenting interventions targeting children’s dietary intake and physical activity should encourage parents to use more positive reinforcement and monitor their children’shealthbehaviorsastheseparentingstylesare associated with healthier behaviors. Moreover, intervention researchers may want to encourage Latino parents to use less controlling styles with girls as this parenting style increased girls’ risk for unhealthy eating.

Remittances as insurance: evidence from Mexican immigrants

Abstract: We argue that remittances are, in part, transferred to the home country to purchase family-provided insurance and self-insurance. We use data on Mexican immigrants with work experience in the United States to capture the motives for sending remittances and use a novel approach to test for the insurance motive by relating host economy risk levels to remittance flows. We find that increases in income risk significantly raises both the propensity and the proportion of labor earnings sent home for family-provided insurance and for self-insurance.

Constraints on the high-density nuclear equation of state from the phenomenology of compact stars and heavy-ion collisions

Abstract: A new scheme for testing nuclear matter equations of state (EoSs) at high densities using constraints from neutron star (NS) phenomenology and a flow data analysis of heavy-ion collisions is suggested. An acceptable EoS shall not allow the direct Urca process to occur in NSs with masses below 1.5M� , and also shall not contradict flow and kaon production data of heavy-ion collisions. Compact star constraints include the mass

Migration, remittances, and male and female employment patterns

Abstract: Little is known about the labor market impacts of workers’ remittances, despite their magnitude in countries with considerable outmigration. Reports that families receiving international remittances severely curtail their work efforts are fairly common in the popular press (e.g., Robert Frank, 2001). Yet, we lack rigorous analyses of how male and female labor supplies respond to increases in remittance income to either support or refute these anecdotal observations. According to the neoclassical model of labor-leisure choice (Mark R. Killingsworth, 1983), remittances—a source of nonlabor income—may lift budget constraints, raise reservation wages, and, through an income effect, reduce the employment likelihood and hours worked by remittance-receiving individuals. The receipt of remittances is usually preceded by the out-migration of working-aged household members, however, which may induce changes in the labor supply of nonmigrating household members in order to compensate for forgone income or to defray migration-related expenses. Distinguishing the disruptive effect from the income effect of remittance inflows is problematic, as most surveys do not contain detailed information on household outmigration and remittance receipt. To the extent that these two effects are expected to have opposite impacts on labor supply, however, we can assess which effect dominates. The impact of remittances on the decision to work has been previously examined by Edgard Rodriguez and Erwin R. Tiongson (2001) in Manila and by Edward Funkhouser (1992) in Managua. Without accounting for the endogeneity of remittances with respect to labor supply, they conclude that remittances reduce employment. Funkhouser also finds that remittances slightly increase self-employment. While informative, these studies focus on the decision to work and do not consider that, without altering employment rates, remittances may change the hours worked and/or the type of work performed in the receiving economy. Furthermore, the impact may be different on male and female labor supplies and responsiveness to remittance income may vary from rural to urban areas. Using data from Mexico—a country with a large and growing remittance inflow—we address the following questions: How does the employment status and hours worked by men and women vary owing to international remittances? Do male and female labor supplies differ across various types of employment in rural versus urban areas due to higher remittance inflows?

A Model of Knowledge Management Success

Abstract: This article describes a knowledge management (KM) success model that is derived from observations generated through a longitudinal study of KM in an engineering organization and KM success factors found in the literature, which were modified by the application of these observations and success factors in various projects. The DeLone and McLean (1992, 2003) IS Success Model was used as a framework for the model, since it was found to fit the observed success criteria and provided an accepted theoretical basis for the proposed model.