bluuebunny/crossref_metadata_2025 huggingface dataset:
Integral projection models for populations in temporally varying environments
Authors: Rees Mark , Ellner Stephen P.
Published: October 2009

Most plant and animal populations have substantial interannual variability in survival, growth rate, and fecundity. They also exhibit substantial variability among individuals in traits such as size, age, condition, and disease status that have large impacts on individual fates and consequently on the future of the population. We present here methods for constructing and analyzing a stochastic integral projection model (IPM) incorporating both of these forms of variability, illustrated through a case study of the monocarpic thistle Carlina vulgaris. We show how model construction can exploit the close correspondence between stochastic IPMs and statistical analysis of trait–fate relationships in a “mixed” or “hierarchical” models framework. This correspondence means that IPMs can be parameterized straightforwardly from data using established statistical techniques and software (vs. the largely ad hoc methods for stochastic matrix models), properly accounting for sampling error and between‐year sample size variation and with vastly fewer parameters than a conventional stochastic matrix model. We show that the many tools available for analyzing stochastic matrix models (such as stochastic growth rate, λS, small variance approximations, elasticity/sensitivity analysis, and life table response experiment [LTRE] analysis) can be used for IPMs, and we give computational formulas for elasticity/sensitivity analyses. We develop evolutionary analyses based on the connection between growth rate sensitivity and selection gradients and present a new method using techniques from functional data analysis to study the evolution of function‐valued traits such as size‐dependent flowering probability. For Carlina we found consistent selection against variability in both state‐specific transition rates and the fitted functions describing state dependence in demographic rates. For most of the regression parameters defining the IPM there was also selection against temporal variance; however, in some cases the effects of nonlinear averaging were big enough to favor increased temporal variation. The LTRE analysis identified year‐to‐year variation in survival as the dominant factor in population growth variability. Evolutionary analysis of flowering strategy showed that the entire functional relationship between plant size and flowering probability is at or near an evolutionarily stable strategy (ESS) shaped by the size‐specific trade‐off between the benefit (fecundity) and cost (mortality) of flowering in a temporally varying environment.
Natural variation in morphology of larval amphibians: Phenotypic plasticity in nature?
Authors: Buskirk Josh Van
Published: October 2009

Phenotypic plasticity has been studied intensively in experimental settings but infrequently in nature, and therefore the relevance of experimental findings is poorly known. This is especially true for morphological plasticity in amphibian larvae induced by predators and competitors. This paper describes a seven‐year survey of head and tail shape in eight species of anuran and newt larvae in northern Switzerland, involving 6824 individual larvae and 59 ponds. I tested relationships between geometric measures of size and shape and five habitat gradients: pond permanence, cover by forest canopy and aquatic vegetation, and the densities of predators and competitors. Responses to competitors and predators were often similar to those reported in experiments. High competitor density was associated with small size and a large head in newt larvae, a long or deep head/body in anuran larvae, and a short or shallow tail in newts and some tadpoles. High predator density was correlated with a deep tail fin and tail muscle in many species. In anurans, the change in shape between low‐ and high‐predator ponds in nature closely paralleled the plastic response to nonlethal predators in mesocosm experiments. The survey revealed many previously undescribed relationships between morphology and the other habitat features. Several species had relatively large tails in ponds that were shaded or thickly vegetated. Associations between year‐to‐year changes in shape and habitat within ponds implicated phenotypic plasticity rather than genetic population divergence, at least in anurans. These results inspire confidence in the relevance of experiments and highlight many new patterns that will merit further study.
Racial Differences in the Relationship Between Alcohol Consumption in Early Adulthood and Occupational Attainment at Midlife
Authors: Sloan Frank A. , Malone Patrick S. , Kertesz Stefan G. , Wang Yang , Costanzo Philip R.
Published: October 2009

Objectives. We assessed the relationship between alcohol consumption in young adulthood (ages 18–30 years) and occupational success 15 years later among Blacks and Whites.

Methods. We analyzed data from the Coronary Artery Risk Development in Young Adults Study on employment status and occupational prestige at year 15 from baseline. The primary predictor was weekly alcohol use at baseline, after stratification by race and adjustment for socioeconomic factors.

Results. We detected racial differences in the relationship between alcohol use in early adulthood and employment status at midlife. Blacks who were very heavy drinkers at baseline were more than 4 times as likely as Blacks who were occasional drinkers to be unemployed at year 15 (odds ratio [OR] = 4.34; 95% confidence interval [CI] = 2.22, 8.47). We found no statistically significant relationship among Whites. Occupational prestige at midlife was negatively related to very heavy drinking, but after adjustment for marital status, active coping, life stress, and educational attainment, this relationship was statistically significant only among Blacks.

Conclusions. Heavy drinking during young adulthood was negatively associated with labor market success at midlife, especially among Blacks.
The NYC Condom: Use and Acceptability of New York City's Branded Condom
Authors: Burke Ryan C. , Wilson Juliet , Bernstein Kyle T. , Grosskopf Nicholas , Murrill Christopher , Cutler Blayne , Sweeney Monica , Begier Elizabeth M.
Published: October 2009

We assessed awareness and experience with the NYC Condom via surveys at 7 public events targeting priority condom distribution populations during 2007. Most respondents (76%) were aware of NYC Condoms. Of those that had obtained them, 69% had used them. Most (80%) wanted alternative condoms offered for free: 22% wanted ultra-thin, 18% extra-strength, and 14% larger-size. Six months after the NYC Condom launch, we found high levels of awareness and use. Because many wanted alternative condoms, the Department of Health and Mental Hygiene began distributing the 3 most-requested alternatives.
Health Care Coverage and the Health Care Industry
Authors: Chou Chiu-Fang , Johnson Pamela Jo , Ward Andrew , Blewett Lynn A.
Published: October 2009

Objectives. We examined rates of uninsurance among workers in the US health care workforce by health care industry subtype and workforce category.

Methods. We used 2004 to 2006 National Health Interview Survey data to assess health insurance coverage rates. Multivariate logistic regression analyses were conducted to estimate the odds of uninsurance among health care workers by industry subtype.

Results. Overall, 11% of the US health care workforce is uninsured. Ambulatory care workers were 3.1 times as likely as hospital workers (95% confidence interval [CI] = 2.3, 4.3) to be uninsured, and residential care workers were 4.3 times as likely to be uninsured (95% CI = 3.0, 6.1). Health service workers had 50% greater odds of being uninsured relative to workers in health diagnosing and treating occupations (odds ratio [OR] = 1.5; 95% CI = 1.0, 2.4).

Conclusions. Because uninsurance leads to delays in seeking care, fewer prevention visits, and poorer health status, the fact that nearly 1 in 8 health care workers lacks insurance coverage is cause for concern.
Forecasting the Future Economic Burden of Current Adolescent Overweight: An Estimate of the Coronary Heart Disease Policy Model
Authors: Lightwood James , Bibbins-Domingo Kirsten , Coxson Pamela , Wang Y. Claire , Williams Lawrence , Goldman Lee
Published: October 2009

Objectives. We predicted the future economic burden attributable to high rates of current adolescent overweight.

Methods. We constructed models to simulate the costs of excess obesity and associated diabetes and coronary heart disease (CHD) among adults aged 35–64 years in the US population in 2020 to 2050.

Results. Current adolescent overweight is projected to result in 161 million life-years complicated by obesity, diabetes, or CHD and 1.5 million life-years lost. The cumulative excess attributable total costs are estimated at $254 billion: $208 billion because of lost productivity from earlier death or morbidity and $46 billion from direct medical costs. Currently available therapies for hypertension, hyperlipidemia, and diabetes, used according to guidelines, if applied in the future, would result in modest reductions in excess mortality (decreased to 1.1 million life-years lost) but increase total excess costs by another $7 billion (increased to $261 billion total).

Conclusions. Current adolescent overweight will likely lead to large future economic and health burdens, especially lost productivity from premature death and disability. Application of currently available medical treatments will not greatly reduce these future burdens of increased adult obesity.
Effects of Sustained Abstinence Among Treated Substance-Abusing Homeless Persons on Housing and Employment
Authors: Milby Jesse B. , Schumacher Joseph E. , Wallace Dennis , Vuchinich Rudy , Mennemeyer Stephen T. , Kertesz Stefan G.
Published: October 2009

Objectives. We examined whether cocaine-dependent homeless persons had stable housing and were employed 6, 12, and 18 months after they entered a randomized controlled trial comparing 2 treatments.

Methods. One group (n = 103) received abstinence-contingent housing, vocational training, and work; another group (n = 103) received the same intervention plus cognitive behavioral day treatment. We examined baseline and early treatment variables for association with long-term housing and employment.

Results. Although the enhanced-treatment group achieved better abstinence rates, the groups did not differ in long-term housing and employment stability. However, consecutive weeks of abstinence during treatment (and to a lesser extent, older age and male gender) predicted long-term housing and employment stability after adjustment for baseline differences in employment, housing, and treatment.

Conclusions. Our data showed a relationship of abstinence with housing stability. Contrasting these results with the increasingly popular Housing First interventions reveals important gaps in our knowledge to be addressed in future research.
State-Level Policies and Psychiatric Morbidity In Lesbian, Gay, and Bisexual Populations
Authors: Hatzenbuehler Mark L. , Keyes Katherine M. , Hasin Deborah S.
Published: October 2009

Objectives. We investigated the modifying effect of state-level policies on the association between lesbian, gay, or bisexual status and the prevalence of psychiatric disorders.

Methods. Data were from wave 2 of the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC), a nationally representative study of noninstitutionalized US adults (N = 34 653). States were coded for policies extending protections against hate crimes and employment discrimination based on sexual orientation.

Results. Compared with living in states with policies extending protections, living in states without these policies predicted a significantly stronger association between lesbian, gay, or bisexual status and psychiatric disorders in the past 12 months, including generalized anxiety disorder (F = 3.87; df = 2; P = .02), post-traumatic stress disorder (F = 3.42; df = 2; P = .04), and dysthymia (F = 5.20; df = 2; P = .02). Living in states with policies that did not extend protections also predicted a stronger relation between lesbian, gay, or bisexual status and psychiatric comorbidity (F = 2.47; df = 2; P = .04).

Conclusions. State-level protective policies modify the effect of lesbian, gay, or bisexual status on psychiatric disorders. Policies that reduce discrimination against gays and lesbians are urgently needed to protect the health and well-being of this population.
Characteristics of Health Information Gatherers, Disseminators, and Blockers Within Families at Risk of Hereditary Cancer: Implications for Family Health Communication Interventions
Authors: Koehly Laura M. , Peters June A. , Kenen Regina , Hoskins Lindsey M. , Ersig Anne L. , Kuhn Natalia R. , Loud Jennifer T. , Greene Mark H.
Published: October 2009

Objectives. Given the importance of the dissemination of accurate family history to assess disease risk, we characterized the gatherers, disseminators, and blockers of health information within families at high genetic risk of cancer.

Methods. A total of 5466 personal network members of 183 female participants of the Breast Imaging Study from 124 families with known mutations in the BRCA1/2 genes (associated with high risk of breast, ovarian, and other types of cancer) were identified by using the Colored Eco-Genetic Relationship Map (CEGRM). Hierarchical nonlinear models were fitted to characterize information gatherers, disseminators, and blockers.

Results. Gatherers of information were more often female (P < .001), parents (P < .001), and emotional support providers (P < .001). Disseminators were more likely female first- and second- degree relatives (both P < .001), family members in the older or same generation as the participant (P < .001), those with a cancer history (P < .001), and providers of emotional (P < .001) or tangible support (P < .001). Blockers tended to be spouses or partners (P < .001) and male, first-degree relatives (P < .001).

Conclusions. Our results provide insight into which family members may, within a family-based intervention, effectively gather family risk information, disseminate information, and encourage discussions regarding shared family risk.
Increasing Youths' Exposure to a Tobacco Prevention Media Campaign in Rural and Low-Population-Density Communities
Authors: Duke Jennifer C. , Vallone Donna M. , Allen Jane A. , Cullen Jennifer , Mowery Paul D. , Xiao Haijun , Dorrler Nicole , Asche Eric T. , Healton Cheryl
Published: October 2009

Objectives. We examined the effectiveness of a program to increase exposure to national “truth” tobacco countermarketing messages among youths in rural and low-population-density communities.

Methods. A longitudinal survey of 2618 youths aged 12 to 17 years was conducted over 5 months in 8 media markets receiving supplemental advertising and 8 comparison markets receiving less than the national average of “truth” messages.

Results. Confirmed awareness of “truth” increased from 40% to 71% among youths in treatment markets while remaining stable in comparison markets. Over 35% of all youths who were unaware of the campaign at baseline became aware of it as a direct result of the increased advertising. Youths living in rural and low-population-density communities were receptive to the campaign's messages.

Conclusions. Through purchase of airtime in local broadcast media, the reach of a national tobacco countermarketing campaign was expanded among youths living in rural and low-population-density areas. This strategy of augmenting delivery of nationally broadcast antitobacco ads can serve as a model for leveraging limited tobacco control resources to increase the impact of evidence-based tobacco prevention campaigns.
Reframing the Dissemination Challenge: A Marketing and Distribution Perspective
Authors: Kreuter Matthew W. , Bernhardt Jay M.
Published: October 2009

A fundamental obstacle to successful dissemination and implementation of evidence-based public health programs is the near-total absence of systems and infrastructure for marketing and distribution.

We describe the functions of a marketing and distribution system, and we explain how it would help move effective public health programs from research to practice. Then we critically evaluate the 4 dominant strategies now used to promote dissemination and implementation, and we explain how each would be enhanced by marketing and distribution systems.

Finally, we make 6 recommendations for building the needed system infrastructure and discuss the responsibility within the public health community for implementation of these recommendations. Without serious investment in such infrastructure, application of proven solutions in public health practice will continue to occur slowly and rarely.
Audience Segmentation as a Social-Marketing Tool in Health Promotion: Use of the Risk Perception Attitude Framework in HIV Prevention in Malawi
Authors: Rimal Rajiv N. , Brown Jane , Mkandawire Glory , Folda Lisa , Böse Kirsten , Creel Alisha H.
Published: October 2009

Objectives. We sought to determine whether individuals' risk perceptions and efficacy beliefs could be used to meaningfully segment audiences to assist interventions that seek to change HIV-related behaviors.

Methods. A household-level survey of individuals (N = 968) was conducted in 4 districts in Malawi. On the basis of responses about perceptions of risk and beliefs about personal efficacy, we used cluster analysis to create 4 groups within the risk perception attitude framework: responsive (high risk, strong efficacy), avoidance (high risk, weak efficacy), proactive (low risk, strong efficacy), and indifference (low risk, weak efficacy). We ran analysis of covariance models (controlling for known predictors) to determine how membership in the risk perception attitude framework groups would affect knowledge about HIV, HIV-testing uptake, and condom use.

Results. A significant association was found between membership in 1 or more of the 4 risk perception attitude framework groups and the 3 study variables of interest: knowledge about HIV (F8, 956 = 20.77; P < .001), HIV testing uptake (F8, 952 = 10.91; P < .001), and condom use (F8, 885 = 29.59; P < .001).

Conclusions. The risk perception attitude framework can serve as a theoretically sound audience segmentation technique that can be used to determine whether messages should augment perceptions of risk, beliefs about personal efficacy, or both.
From Health as a Rational Choice to Health as an Affordable Choice
Authors: Maziak Wasim , Ward Kenneth D.
Published: October 2009

Sedentary, consumption-based lifestyles are placing entire populations at serious health risks; obesity is a prime example.

The individual approach to obesity, which targets those at risk, has largely failed because it ignores wider influences on behavior. Although the population–ecological approach is gaining support, it cannot disentangle clear targets for policy change. Consequently, health promotion has been relegated to the mass marketing of healthy behaviors, which is based on a rational notion that informed people tend to behave in their best interest.

Creating environments that support behavior change and providing individuals incentives can be more effective to reduce lifestyle-related risks. A paradigm shift from trying to sell health to the public to creating the conditions whereby healthy choices become accessible and affordable is required.
Participatory Design of Mass Health Communication in Three Languages for Seniors and People With Disabilities on Medicaid
Authors: Neuhauser Linda , Rothschild Beccah , Graham Carrie , Ivey Susan L. , Konishi Susana
Published: October 2009

Objectives. We used participatory design methods to develop and test guidebooks about health care choices intended for 600 000 English-, Spanish-, and Chinese-speaking seniors and people with disabilities receiving Medicaid in California.

Methods. Design and testing processes were conducted with consumers and professionals; they included 24 advisory group interviews, 36 usability tests, 18 focus groups (105 participants), 51 key informant interviews, guidebook readability and suitability testing, linguistic adaptation, and iterative revisions of 4 prototypes.

Results. Participatory design processes identified preferences of intended audiences for guidebook content, linguistic adaptation, and format; guidebook readability was scored at the sixth- to eighth-grade level and suitability at 95%. These findings informed the design of a separate efficacy study that showed high guidebook usage and satisfaction, and better gains in knowledge, confidence, and intended behaviors among intervention participants than among control participants.

Conclusions. Participatory design can be used effectively in mass communication to inform vulnerable audiences of health care choices. The techniques described can be adapted for a broad range of health communication interventions.
Impact of an Organizational Intervention Designed to Improve Snack and Beverage Quality in YMCA After-School Programs
Authors: Mozaffarian Rebecca S. , Wiecha Jean L. , Roth Barbara A. , Nelson Toben F. , Lee Rebekka M. , Gortmaker Steven L.
Published: October 2009

Objectives. We evaluated the quality of snacks and beverages served at YMCA after-school programs before and after the programs' participation in a YMCA Learning Collaborative.

Methods. We collected data on the types and brands of snacks and beverages (including fresh fruits and vegetables, whole grains, foods with trans fats, water, and sugar-sweetened beverages) served daily during 3 different time periods spanning 14 months in total, and the components of the healthy eating standards. We compared snack and beverage quality before and after the intervention.

Results. Weekly servings of fresh fruits and vegetables (1.3 vs 3.9; P = .02) and weekly servings of fruits and vegetables as a whole (1.9 vs 5.2; P = .009) increased from baseline to postintervention; weekly servings of desserts (1.3 vs 0.5; P = .049), foods with added sugars (3.9 vs 2.4; P = .03), and foods containing trans fats (2.6 vs 0.7; P = .01) decreased. After the intervention, all YMCAs offered water daily, and none served sugar-sweetened beverages. The percentage of calories from fruits and vegetables significantly increased after the intervention, whereas the percentage of calories from foods containing trans fats and added sugars decreased.

Conclusions. A learning collaborative can disseminate healthy eating standards among participating organizations and facilitate improvements in the quality of after-school snacks and beverages.
Toward a Dynamic Conceptualization of Social Ties and Context: Implications for Understanding Immigrant and Latino Health
Authors: Viruell-Fuentes Edna A. , Schulz Amy J.
Published: October 2009

Researchers have posited that social ties and social support may contribute to better-than-expected health outcomes among Mexican immigrants vis-à-vis their US-born counterparts. However, in our review of studies examining social ties and health by immigration-related variables among this group, we found little support for this hypothesis. To better understand the social factors that contribute to the health of Mexicans in the United States, we conducted a qualitative analysis of social relationships and social context among first- and second-generation Mexican women. Our results highlight the interplay between immigration processes and social ties, draw attention to the importance of identity support and transnational social relationships, and suggest ways to reconceptualize the relationship between social contexts, social ties, and immigrant and Latino health.
School-Based Condom Education and Its Relations With Diagnoses of and Testing for Sexually Transmitted Infections Among Men in the United States
Authors: Dodge Brian , Reece Michael , Herbenick Debby
Published: October 2009

An intense social and political debate continues in the United States regarding sexuality education. Included in the debate are those who favor comprehensive approaches, those who favor abstinence-only approaches, and those who favor no sexuality education. In this study, we showed that men who received school-based condom education were less likely to have been diagnosed with sexually transmitted infections (STIs) and were more likely to ever have been tested for sexually transmitted infections than were men without such education. School-based condom education is associated with less, rather than more, STI risk.
Changes in Postmenopausal Hormone Replacement Therapy Use Among Women With High Cardiovascular Risk
Authors: Hsu Angela , Card Andrea , Lin Susan Xiaoqin , Mota Sean , Carrasquillo Olveen , Moran Andrew
Published: October 2009

After randomized trials failed to support the use of hormone replacement therapy (HRT) for preventing cardiovascular disease (CVD), HRT use for postmenopausal women declined. Our analysis of 1999–2000 and 2003–2004 National Health and Nutrition Surveys (NHANES) shows that HRT use decreased 19% (from 27.6 to 8.4%; P < .001) among women with CVD versus 3% (from 19.8 to 16.8%; P = .68) among low-risk women, suggesting that most of the drop in HRT use may be among women prescribed HRT as an unproven treatment to prevent CVD.
Communicating Treatment Risk Reduction to People With Low Numeracy Skills: A Cross-Cultural Comparison
Authors: Garcia-Retamero Rocio , Galesic Mirta
Published: October 2009

Objectives. We sought to address denominator neglect (i.e. the focus on the number of treated and nontreated patients who died, without sufficiently considering the overall numbers of patients) in estimates of treatment risk reduction, and analyzed whether icon arrays aid comprehension.

Methods. We performed a survey of probabilistic, national samples in the United States and Germany in July and August of 2008. Participants received scenarios involving equally effective treatments but differing in the overall number of treated and nontreated patients. In some conditions, the number who received a treatment equaled the number who did not; in others the number was smaller or larger. Some participants received icon arrays.

Results. Participants—particularly those with low numeracy skills—showed denominator neglect in treatment risk reduction perceptions. Icon arrays were an effective method for eliminating denominator neglect. We found cross-cultural differences that are important in light of the countries' different medical systems.

Conclusions. Problems understanding numerical information often reside not in the mind but in the problem's representation. These findings suggest suitable ways to communicate quantitative medical data.
Text4Health: A Qualitative Evaluation of Parental Readiness for Text Message Immunization Reminders
Authors: Kharbanda Elyse Olshen , Stockwell Melissa S. , Fox Harrison W. , Rickert Vaughn I.
Published: October 2009

We conducted focus groups and individual interviews in a diverse population of parents to qualitatively explore preferences and readiness for text message immunization reminders. We used content analysis to review and independently code transcripts. Text message reminders were well-accepted by parents; many thought they would be more effective than standard phone or mail reminders. Parents preferred text message reminders to be brief and personalized. Most parents were able to retrieve sample text messages but many had difficulty with interactive texting.
Effects of Different Types of Antismoking Ads on Reducing Disparities in Smoking Cessation Among Socioeconomic Subgroups
Authors: Durkin Sarah J. , Biener Lois , Wakefield Melanie A.
Published: October 2009

Objectives. We assessed which types of mass media messages might reduce disparities in smoking prevalence among disadvantaged population subgroups.

Methods. We followed 1491 adult smokers over 24 months and related quitting status at follow-up to exposure to antismoking ads in the 2 years prior to the baseline assessment.

Results. On average, smokers were exposed to more than 200 antismoking ads during the 2-year period, as estimated by televised gross ratings points (GRPs). The odds of having quit at follow-up increased by 11% with each 10 additional potential ad exposures (per 1000 points, odds ratio [OR] = 1.11; 95% confidence interval [CI] = 1.00, 1.23; P < .05). Greater exposure to ads that contained highly emotional elements or personal stories drove this effect (OR = 1.14; 95% CI 1.02, 1.29; P < .05), which was greater among respondents with low and mid-socioeconomic status than among high–socioeconomic status groups.

Conclusions. Emotionally evocative ads and ads that contain personalized stories about the effects of smoking and quitting hold promise for efforts to promote smoking cessation and reduce socioeconomic disparities in smoking.
The Geomechanics Of A Shale Play: What Makes A Shale Prospective!
Authors: Britt Larry K. , Schoeffler Jerry
Published: October 2009

Many shale plays are being successfully developed throughout North America. These shale plays are being evaluated based on a number of criteria, but primarily through typical unconventional and tight formation gas reservoir characteristics. Prospective shale plays share several interesting characteristics such as mineralogy, rock mechanics, and geomechanics. It is the intent of this paper to highlight and demonstrate the interrelationship of these characteristics, and to show their importance on completion and stimulation design and more importantly to the very prospectivity of an unconventional shale play.

This paper will first show, through an analysis of the mineralogy, that shale plays are made up of mostly silica and carbonate material and have few clay constituents. In other words, the prospective shales are actually fine-grained clastics and not shale!Second, prospective shales tend to be brittle, with the static Young’s Modulus generally in excess of 3.5 x 106 psi. Of course, this brittleness is related to the lack of clay constituents that make up these rocks. In addition, prospective shales tend to satisfy clastic correlations of dynamic to static Young’s Modulus. They do not behave like typical shales, but more like fine-grained isotropic (on a core scale) clastics!

Finally, gas can flow through induced fractures or natural fissures under effective stress conditions in these shale plays. As a result, water-frac treatments are the stimulation of choice! However, proppant is still necessary in at least the near wellbore vicinity to provide a conductive pathway to the wellbore. This paper focuses on three key elements (mineralogy, rock mechanics, and geomechanics) of prospective shale plays and benefits the petroleum industry by:Integrating the laboratory core work with multi-disciplinary data to develop a shale and unconventional reservoir prospectivity evaluation tool,Illustrating how this multi-disciplinary dataset influences completion and stimulation design, execution, and well performance, andDemonstrating how this multi-discipline dataset can be used to identify and mitigate well completion and stimulation risks in these unconventional reservoirs.
Horizontal Well Completion, Stimulation Optimization, and Risk Mitigation
Authors: Britt Larry K. , Smith Michael B.
Published: October 2009

Horizontal wells have become the industry standard for unconventional and tight formation gas reservoirs. Because these reservoirs have poorer quality pay, it takes a good, well-planned completion and fracture stimulation(s) to make an economic well. Even in a sweet spot in the unconventional and tight gas reservoir, good completion and stimulation practices are required; otherwise, a marginal or uneconomic well will result. But what are good completion and stimulation practices in horizontal wells? What are the objectives of horizontal wells and how do we relate the completion and stimulation(s) to achieving these goals? How many completions/stimulations do we need for best well performance and/or economics? How do we maximize the value from horizontal wells? When should a horizontal well be drilled longitudinally or transverse? These are just a few questions to be addressed in the subsequent paragraphs.

This paper focuses on some of the key elements of well completions and stimulation practices as they apply to horizontal wells. Optimization studies will be shown and used to highlight the importance of lateral length, number of fractures, inter-fracture distance, fracture half-length, and fracture conductivity. These results will be used to discuss the various completion choices such as cased and cemented, open hole with external casing packers, and open hole "pump and pray" techniques. This paper will also address key risks to horizontal wells and develop risk mitigation strategies so that project economics can be maximized. In addition, a field case study will be shown to illustrate the application of these design, optimization, and risk mitigation strategies for horizontal wells in tight and unconventional gas reservoirs.

This work provides insight for the completion and stimulation design engineers by: developing well performance and economic objectives for horizontal wells and highlighting the incremental benefits of various completion and stimulation strategies,establishing well performance and economic based criteria for drilling longitudinal or transverse horizontal wells,integrating the reservoir objectives and geomechanic limitations into a horizontal well completion and stimulation strategy, andidentifying horizontal well completion and stimulation risks and risk mitigation strategies for pre-horizontal well planning purposes.
Field Test of Wettability Alteration to Increase the Flow Rate from Aquifer Gas Storage Wells
Authors: Weiss William W. , Xie Xina , Weiss Jason W.
Published: October 2009

The St. Peter aquifer in northern Illinois is used to store natural gas during the summer months for the winter heating season. Since the fresh water aquifer is strongly water-wet, the capillary force promotes the retention of water in the pores to curtail the deliverability of gas to the wellbore during withdrawal. Similarly, the injection of gas during the filling cycle is also hampered. Laboratory work performed earlier demonstrated that the surfactant Tomadry N-4 could alter the wettability of the St. Peter core samples from strongly water-wet to neutral-wet, which in turn increased the gas deliverability. A field test was performed based on the laboratory results. The Waverly Storage Facility operated by Southern Union/Panhandle Energy was selected as the site for the field test of surfactant treatment. The storage reservoir is an 1800-ft sandstone aquifer located near Springfield, Illinois. Expansion and contraction of a spherical gas bubble provided pressure support as gas was injected and withdrawn from 37 individual wells. Three wells were selected for treatment with 1000 bbl of ~4% Tomadry N-4 solution. An additional three wells nearby were selected as control wells. The wells were treated at the end of the 2007 injection cycle, and the rate-pressure performance of the three treated wells and three control wells through the first month of 2009 was analyzed. Use of the productivity index technique was not as insightful as the conventional rate vs. cumulative production analysis technique. The Waverly test is belived to be the first field experiment of altering wettability to improve gas flow rates. Graphical presentation of the data suggests that at the beginning of the withdrawal cycle and injection period, the performance of the surfactant-treated wells was better than the control wells. The test results are encouraging, and further field tests should be developed. It appears that the gas withdrawal rate from two of the three treated wells was about 33% greater than prior to treatment.
The Valuation of Toll Roads and the Implication for Future Solvency with Special Reference to the Transurban Group
Authors: Goldberg John L
Published: October 2009

The capital asset pricing model (CAPM) and the discounted cash flow (DCF) method have been used to establish a 95% confidence interval for the value of the Transurban Group, owners and operators of toll roads in Australia and the United States. As the value claimed in the financial statements is well in excess of the upper limit, it is concluded that Transurban is overvalued. This conclusion is supported by other evidence. Overvaluation has increased the risk of insolvency through excessive borrowing. For example, in 2008 cash at bank was only about 5% of the total liabilities.
Village Economies and the Structure of Extended Family Networks
Authors: Angelucci Manuela , De Giorgi Giacomo , Rangel Marcos , Rasul Imran
Published: October 2009

This paper documents how the structure of extended family networks in rural Mexico relates to the poverty and inequality of the village of residence. Using the Hispanic naming convention, we construct within-village extended family networks in 504 poor rural villages. Family networks are larger (both in the number of members and as a share of the village population) and out-migration is lower the poorer and the less unequal the village of residence. Our results are consistent with the extended family being a source of informal insurance to its members.
Carbohydrate-Responsive Element-Binding Protein (ChREBP) Is a Negative Regulator of ARNT/HIF-1β Gene Expression in Pancreatic Islet β-Cells
Authors: Noordeen Nafeesa A. , Khera Tarnjit K. , Sun Gao , Longbottom E. Rebecca , Pullen Timothy J. , da Silva Xavier Gabriela , Rutter Guy A. , Leclerc Isabelle
Published: October 2009

OBJECTIVE

Carbohydrate-responsive element-binding protein (ChREBP) is a transcription factor that has been shown to regulate carbohydrate metabolism in the liver and pancreatic β-cells in response to elevated glucose concentrations. Because few genes have been identified so far as bona fide ChREBP-target genes, we have performed a genome-wide analysis of the ChREBP transcriptome in pancreatic β-cells.

RESEARCH DESIGN AND METHODS

Chromatin immunoprecipitation and high-density oligonucleotide tiling arrays (ChIP-chip; Agilent Technologies) using MIN6 pancreatic β-cell extracts were performed together with transcriptional and other analysis using standard techniques.

RESULTS

One of the genes identified by ChIP-chip and linked to glucose sensing and insulin secretion was aryl hydrocarbon receptor nuclear translocator (ARNT)/hypoxia-inducible factor-1β (HIF-1β), a transcription factor implicated in altered gene expression and pancreatic-islet dysfunction in type 2 diabetes. We first confirmed that elevated glucose concentrations decreased ARNT/HIF-1β levels in INS-1 (832/13) cells and primary mouse islets. Demonstrating a role for ChREBP in ARNT gene regulation, ChREBP silencing increased ARNT mRNA levels in INS-1 (832/13) cells, and ChREBP overexpression decreased ARNT mRNA in INS-1 (832/13) cells and primary mouse islets. We demonstrated that ChREBP and Max-like protein X (MLX) bind on the ARNT/HIF-1β promoter on the proximal region that also confers the negative glucose responsiveness.

CONCLUSIONS

These results demonstrate that ChREBP acts as a novel repressor of the ARNT/HIF-1β gene and might contribute to β-cell dysfunction induced by glucotoxicity.
Proteomics Analysis of Human Skeletal Muscle Reveals Novel Abnormalities in Obesity and Type 2 Diabetes
Authors: Hwang Hyonson , Bowen Benjamin P. , Lefort Natalie , Flynn Charles R. , De Filippis Elena A. , Roberts Christine , Smoke Christopher C. , Meyer Christian , Højlund Kurt , Yi Zhengping , Mandarino Lawrence J.
Published: October 2009

OBJECTIVE

Insulin resistance in skeletal muscle is an early phenomenon in the pathogenesis of type 2 diabetes. Studies of insulin resistance usually are highly focused. However, approaches that give a more global picture of abnormalities in insulin resistance are useful in pointing out new directions for research. In previous studies, gene expression analyses show a coordinated pattern of reduction in nuclear-encoded mitochondrial gene expression in insulin resistance. However, changes in mRNA levels may not predict changes in protein abundance. An approach to identify global protein abundance changes involving the use of proteomics was used here.

RESEARCH DESIGN AND METHODS

Muscle biopsies were obtained basally from lean, obese, and type 2 diabetic volunteers (n = 8 each); glucose clamps were used to assess insulin sensitivity. Muscle protein was subjected to mass spectrometry–based quantification using normalized spectral abundance factors.

RESULTS

Of 1,218 proteins assigned, 400 were present in at least half of all subjects. Of these, 92 were altered by a factor of 2 in insulin resistance, and of those, 15 were significantly increased or decreased by ANOVA (P < 0.05). Analysis of protein sets revealed patterns of decreased abundance in mitochondrial proteins and altered abundance of proteins involved with cytoskeletal structure (desmin and alpha actinin-2 both decreased), chaperone function (TCP-1 subunits increased), and proteasome subunits (increased).

CONCLUSIONS

The results confirm the reduction in mitochondrial proteins in insulin-resistant muscle and suggest that changes in muscle structure, protein degradation, and folding also characterize insulin resistance.
Age, Obesity, and Sex Effects on Insulin Sensitivity and Skeletal Muscle Mitochondrial Function
Authors: Karakelides Helen , Irving Brian A. , Short Kevin R. , O'Brien Peter , Nair K. Sreekumaran
Published: October 2009

OBJECTIVE

Reductions in insulin sensitivity in conjunction with muscle mitochondrial dysfunction have been reported to occur in many conditions including aging. The objective was to determine whether insulin resistance and mitochondrial dysfunction are directly related to chronological age or are related to age-related changes in body composition.

RESEARCH DESIGN AND METHODS

Twelve young lean, 12 young obese, 12 elderly lean, and 12 elderly obese sedentary adults were studied. Insulin sensitivity was measured by a hyperinsulinemic-euglycemic clamp, and skeletal muscle mitochondrial ATP production rates (MAPRs) were measured in freshly isolated mitochondria obtained from vastus lateralis biopsy samples using the luciferase reaction.

RESULTS

Obese participants, independent of age, had reduced insulin sensitivity based on lower rates of glucose infusion during a hyperinsulinemic-euglycemic clamp. In contrast, age had no independent effect on insulin sensitivity. However, the elderly participants had lower muscle MAPRs than the young participants, independent of obesity. Elderly participants also had higher levels inflammatory cytokines and total adiponectin. In addition, higher muscle MAPRs were also noted in men than in women, whereas glucose infusion rates were higher in women.

CONCLUSIONS

The results demonstrate that age-related reductions in insulin sensitivity are likely due to an age-related increase in adiposity rather than a consequence of advanced chronological age. The results also indicate that an age-related decrease in muscle mitochondrial function is neither related to adiposity nor insulin sensitivity. Of interest, a higher mitochondrial ATP production capacity was noted in the men, whereas the women were more insulin sensitive, demonstrating further dissociation between insulin sensitivity and muscle mitochondrial function.
Idd9.1Locus Controls the Suppressive Activity of FoxP3+CD4+CD25+ Regulatory T-Cells
Authors: Yamanouchi Jun , Puertas Maria-Carmen , Verdaguer Joan , Lyons Paul A. , Rainbow Daniel B. , Chamberlain Giselle , Hunter Kara M. , Peterson Laurence B. , Wicker Linda S. , Santamaria Pere
Published: October 2009

OBJECTIVE

The ∼45-cM insulin-dependent diabetes 9 (Idd9) region on mouse chromosome 4 harbors several different type 1 diabetes–associated loci. Nonobese diabetic (NOD) mice congenic for the Idd9 region of C57BL/10 (B10) mice, carrying antidiabetogenic alleles in three different Idd9 subregions (Idd9.1, Idd9.2, and Idd9.3), are strongly resistant to type 1 diabetes. However, the mechanisms remain unclear. This study aimed to define mechanisms underlying the type 1 diabetes resistance afforded by B10 Idd9.1, Idd9.2, and/or Idd9.3.

RESEARCH DESIGN AND METHODS

We used a reductionist approach that involves comparing the fate of a type 1 diabetes–relevant autoreactive CD8+ T-cell population, specific for residues 206–214 of islet-specific glucose 6 phosphatase catalytic subunit–related protein (IGRP206–214), in noncongenic versus B10 Idd9–congenic (Idd9.1 + Idd9.2 + Idd9.3, Idd9.2 + Idd9.3, Idd9.1, Idd9.2, and Idd9.3) T-cell receptor (TCR)–transgenic (8.3) NOD mice.

RESULTS

Most of the protective effect of Idd9 against 8.3-CD8+ T-cell–enhanced type 1 diabetes was mediated by Idd9.1. Although Idd9.2 and Idd9.3 afforded some protection, the effects were small and did not enhance the greater protective effect of Idd9.1. B10 Idd9.1 afforded type 1 diabetes resistance without impairing the developmental biology or intrinsic diabetogenic potential of autoreactive CD8+ T-cells. Studies in T- and B-cell–deficient 8.3-NOD.B10 Idd9.1 mice revealed that this antidiabetogenic effect was mediated by endogenous, nontransgenic T-cells in a B-cell–independent manner. Consistent with this, B10 Idd9.1 increased the suppressive function and antidiabetogenic activity of the FoxP3+CD4+CD25+ T-cell subset in both TCR-transgenic and nontransgenic mice.

CONCLUSIONS

A gene(s) within Idd9.1 regulates the development and function of FoxP3+CD4+CD25+ regulatory T-cells and, in turn, the activation of CD8+ effector T-cells in the pancreatic draining lymph nodes, without affecting their development or intrinsic diabetogenic potential.
Complement Factor H Is Expressed in Adipose Tissue in Association With Insulin Resistance
Authors: Moreno-Navarrete José María , Martínez-Barricarte Rubén , Catalán Victoria , Sabater Mònica , Gómez-Ambrosi Javier , Ortega Francisco José , Ricart Wifredo , Blüher Mathias , Frühbeck Gema , Rodríguez de Cordoba Santiago , Fernández-Real José Manuel
Published: October 2009

OBJECTIVE

Activation of the alternative pathway of the complement system, in which factor H (fH; complement fH [CFH]) is a key regulatory component, has been suggested as a link between obesity and metabolic disorders. Our objective was to study the associations between circulating and adipose tissue gene expressions of CFH and complement factor B (fB; CFB) with obesity and insulin resistance.

RESEARCH DESIGN AND METHODS

Circulating fH and fB were determined by enzyme-linked immunosorbent assay in 398 subjects. CFH and CFB gene expressions were evaluated in 76 adipose tissue samples, in isolated adipocytes, and in stromovascular cells (SVC) (n = 13). The effects of weight loss and rosiglitazone were investigated in independent cohorts.

RESULTS

Both circulating fH and fB were associated positively with BMI, waist circumference, triglycerides, and inflammatory parameters and negatively with insulin sensitivity and HDL cholesterol. For the first time, CFH gene expression was detected in human adipose tissue (significantly increased in subcutaneous compared with omental fat). CFH gene expression in omental fat was significantly associated with insulin resistance. In contrast, CFB gene expression was significantly increased in omental fat but also in association with fasting glucose and triglycerides. The SVC fraction was responsible for these differences, although isolated adipocytes also expressed fB and fH at low levels. Both weight loss and rosiglitazone led to significantly decreased circulating fB and fH levels.

CONCLUSIONS

Increased circulating fH and fB concentrations in subjects with altered glucose tolerance could reflect increased SVC-induced activation of the alternative pathway of complement in omental adipose tissue linked to insulin resistance and metabolic disturbances.