Discounting and Reciprocity in an Iterated Prisoner’s Dilemma

The Iterated Prisoner’s Dilemma (IPD) is a central paradigm in the study of animal cooperation. According to the IPD framework, repeated play (repetition) and reciprocity combine to maintain a cooperative equilibrium. However, experimental studies with animals suggest that cooperative behavior in IPDs is unstable, and some have suggested that strong preferences for immediate benefits (that is, temporal discounting) might explain the fragility of cooperative equilibria. We studied the effects of discounting and strategic reciprocity on cooperation in captive blue jays. Our results demonstrate an interaction between discounting and reciprocity. Blue jays show high stable levels of cooperation in treatments with reduced discounting when their opponent reciprocates, but their levels of cooperation decline in all other treatment combinations. This suggests that stable cooperation requires both reduced discounting and reciprocity, and it offers an explanation of earlier failures to find cooperation in controlled payoff games

Lee County, North Carolina : a community diagnosis including secondary data analysis and qualitative data collection

This document describes the most salient issues that exist for the residents of Lee County, North Carolina as determined through both primary and secondary data collected for a research project. This research project is called a ‘community diagnosis’ and aims to provide a thorough understanding of a community area by elucidating the assets, challenges, and future directions of the community, as defined by the community. This community diagnosis was conducted by six first-year masters students in the Department of Health Behavior and Health Education of the School of Public Health at the University of North Carolina at Chapel Hill. It was conducted at the request of the Lee County Health Department, and as a requirement of the HBHE 240/241 course at the University of North Carolina. The collection and analysis of the data occurred between September, 1999 through April, 2000, culminating with the production of this document. The document is meant to serve as an aid to community members, the health department, and service providers to address the needs of the community by drawing on the identified strengths and challenges of the community. The Lee County community diagnosis commenced with informal talks with residents of the area, and by taking car tours of the area. Concurrently, we began gathering pre-existing or secondary data. We gathered statistics related to demographics, health status of the residents, economic conditions, as well as other social variables [such as housing] of the area. Much of these data came from sources such as LINC (Logging Into North Carolina), U.S. Census, the State Center for Health Statistics, and the Chamber of Commerce. We also researched the history of the area to provide us with a richer context in which to understand this data. All of this information combined comprises the first section of our document (Community Description, Community Profile and Health). The following is a brief summary of this first section. Lee County is found in the geographical center of North Carolina, and spans 259.3 square miles. Lee County is comprised of eight townships: Deep River, West Sanford, East Sanford, Sanford, Pocket, Cape Fear, Jonesboro, and Greenwood. The only incorporated towns, Sanford and Broadway, are found within the townships of Sanford and Cape Fear, respectively. Lee County was officially incorporated in 1907, building on a strong history of economic growth stemming from natural resources and natural deposits. These natural resources and natural deposits allowed people in the area to develop the mining industry, and in more recent history, agricultural development, and manufacturing. The county grew quickly as people were attracted to the new tobacco farming as well as brick production, which later put Lee on the map as the Brick Capital. Throughout the next few decades, the area continued to grow despite some trouble during the depression. Once World War II had ended, industry prospered. This trend has more or less continued to the present day. Today Lee is a burgeoning industrial and economic center. The economy has shifted from a largely agricultural base to largely a manufacturing base. The manufacturing industry in Lee is currently very strong, accounting for 45% of the county’s total employment. Manufacturing holds five of the ten positions in the Lee County’s top ten employers' list (Chamber of Commerce, 1998). It is largely a result of Lee’s prosperity in that so many people are attracted to and continue to move to Lee County. The largest populated area in Lee County is Sanford, containing over one half (21,100) of the entire county population (48,813) (Chamber of Commerce, 1998). As mentioned above, Lee County has experienced tremendous growth throughout its history, which continues to the present day, much like the rest of North Carolina. There was a 59% increase in the population from 1970-1997, and it is projected that Lee will reach 51,182 in 2000. A good portion of the population growth can be attributed to the influx of Latino/a immigrants, which has shifted the racial composition of the county. In 1990 the racial breakdown of Lee County was 75% White, 21.9% Black, 1.2 % Latino/a, 1.3% other (U.S. Census, 1990). Estimates suggest the Latino/as now make up over 10% of Lee County, with much of this growth occurring over the last decade. Additionally, many people are moving to the area from Research Triangle Park (RTP) to take advantage of Lee’s growing economy. All of this growth, both with respect to population and economy, can be characterized as assets and challenges for the community. After we completed analyzing the data from secondary sources, we went to the community members and service providers themselves to try and get a myriad of perspectives on all of the assets, challenges, and future directions of Lee County. We created three different interview guides, one for community members, one for service providers, and one for focus groups. We selected the people we interviewed based on a list provided by the health department, referrals by other interviewees and our subjective opinion about who might best represent the voices of Lee County. One of our main goals was to hear voices not generally heard. We conducted a total of 26 interviews and four focus groups, which included between five and eleven participants each. What follows is a summary of our findings from these interviews and focus groups, which we refer to as our primary data. They are presented within six major themes: growth in population, jobs/economy, growth as it impacts infrastructure and the environment, health, youth, and recreation. The fact that Lee County is experiencing greater than average population growth surfaced in almost every interview as either or both an asset and a challenge for the community. Some were excited to see Lee evolve and change, while others feared a loss of the ‘small town feel.’ While Lee was considered “a great place to raise a family,” concerns were raised that crime and drug activity were on the rise. Also, there is a perception of division among racial/ethnic groups in Lee County, and that division was generally regarded as disturbing. On the same note, several people spoke of churches playing a seminal role in bringing various groups of people together. Lack of representation of various ethnic groups, as well as women and younger people, was mentioned with regard to city and county governments. The two groups that comprise the large numbers of people migrating into the county are people from Raleigh/Cary/RTP, and Latino/as. Despite the potential of bringing greater wealth into Lee County, there are major concerns regarding the growth of the Raleigh/Cary/RTP population. First, it was feared that the new housing being built for these generally wealthier people would lead to an increase in property values, which in turn would lead to a lack of affordable homes for those with middle or low incomes. Another concern was that Lee was becoming a ‘bedroom community’ to RTP. A third concern was that Lee might grow too quickly and become ‘the next Cary.’ A further concern was heard from communities who wanted to grow with Sanford and not be left behind while other neighborhoods grew. Others concerns surfaced regarding the resulting effects on the infrastructure due to this growth including the need for emergency and transitional housing, lack of public transportation, environmental issues as they relate to both the physical and natural environment, as well as an increase in traffic. The burgeoning Latino/a population in Lee was also viewed as both an asset and a challenge. Some spoke excitedly about a rich, new culture. They also mentioned that Latino/as help keep the economy growing with their hard work and willingness to take jobs others might not want. Some people, however, spoke about Latino/as as a strain on local services. Others spoke of the challenges that Latino/as face with regard to their quality of life in Lee County such as a lack of cultural awareness on the part of the Blacks and Whites, lack of bilingual services, and discrimination. Other challenges include poor housing, lack of representation in the government, and transportation barriers. With regard to jobs and economy, people stated that Lee had a strong and vibrant economy, a diverse industrial base, and a low rate of unemployment. Some challenges facing Lee County residents are the increasing cost of living, and the sentiment that the wages are too low. Finally, the influx of Latino/as was linked to employment in factories in the county. With regard to health, the interviewees’ greatest concerns were diabetes, cancer and HIV/AIDS. Community members were cognizant and generally pleased with the variety of health services. They spoke relatively highly of the Lee County Health Department, the Helping Hands Clinic, and the Central Carolina Hospital. However, they were quick to mention numerous barriers regarding accessing these services. The primary barriers were transportation, lack of bilingual services and cultural sensitivity, and lack of insurance coverage. Special mention was made of the need for increased services for the elderly, expecting mothers and their infants, and for people with substance addictions. With regard to youth, our findings suggest that many community members are concerned about older teens in the community. Many community members and providers expressed concern with the burgeoning high school in Lee. Additionally, drug and alcohol misuse and teenage pregnancy were identified as challenges to older teens. As far as assets were concerned, community members were proud of the programs and resources developed for younger youth, and expressed responsibility of attention to youth issues. In terms of recreation, the majority of the people interviewed felt that Lee County had good, organized youth sports opportunities, but lacked a variety of places to go for entertainment and exercise. Some identified barriers to recreation included lack of space available and a lack of free or inexpensive opportunities. The final component of the Lee County community diagnosis process was the Community Forum, which was held on March 4, 2000 at the Lee County Senior High School cafeteria (see Appendix E). The ultimate goal of the Forum was to share all of the findings from both the primary and secondary data with the community. It was our hope that the community members who came would then prioritize the issues most important to them and create solutions and mobilize around them. Although our turnout was lower than expected, there was vibrant discussion around the issues of health and growth, as well as additional themes born out of the discussion. The issues discussed were recreation, substance abuse, environmental issues, representative government, accurate count for the 2000 U.S. Census, and racial/ethnic barriers. It is our hope that the issues discussed at the Forum and the information presented in this document will be a helpful tool for community development in Lee County. In our interviews and focus groups we heard perspectives on the many assets and challenges of Lee County. What follows is a brief overview of recommendations and potential ways to target some of the issues that emerged in our data. These suggestions by no means imply that these are the sole actions that the community could take to address the issues. It is important to point out that above all, we found many caring, concerned individuals in Lee County, which is what makes Lee County a strong community. One way people in Lee could begin to address some of the challenges they face is to have each existing group, organization, or task force create assets maps, which are ostensibly a list of all the strengths each offers [such as services]. An assets map of the individual strengths of each member of each group or organization could be created as well. All of the groups could combine their assets maps to form a collective map of all of the strengths in Lee County. This collective map could provide a very useful tool to assist the community in addressing issues. More general suggestions are as follows: include youth in planning and discussions of the future of Lee County, address the increasing diversity in a proactive and positive way, utilize the sense of community pride to address issues of growth, and tap the already existing community organizing capabilities to further create change. Ultimately, Lee County is perceived to be a great place to live. It is our hope that our community diagnosis served to further create dialogue about what is important to the people of Lee.Master of Public Healt

Substantial effect of efavirenz monotherapy on bilirubin levels in healthy volunteers

BACKGROUND: Efavirenz exhibits multiple interactions with drug-metabolizing enzymes and transporters, and for this reason efavirenz-based HIV therapy is associated with altered pharmacokinetics of coadministered drugs. Probably by the same mechanism, efavirenz-based HIV therapy affects the disposition of endogenous compounds, but this effect is difficult to directly link with efavirenz because it is used in combination with other drugs. OBJECTIVES: To explore the effect of efavirenz monotherapy on biochemical laboratory values in a clinical trial of healthy volunteers. METHODS: Men and women (aged 18-49 years) with body mass index ≤32 who were assessed to be healthy based on medical history, physical examination, and standard laboratory screening received a single (600 mg) and multiple doses (600 mg/d for 17 days) of efavirenz orally. This trial was designed to determine the pharmacokinetics and drug interactions of efavirenz. As part of this study, analysis of serum chemistries that were measured at study entry (screening) and 1 week after completion of the multiple dose study (exit) is reported. RESULTS: Data from 60 subjects who fully completed and 13 subjects who partially completed the study are presented. Total bilirubin was substantially reduced at exit (by ~30%, with large intersubject variability) compared with screening values (P < 0.0001). The percent changes were in part explained by the intersubject differences in baseline total bilirubin because there was a significant correlation between baseline (screening) values and percent change at exit (r = 0.50; P < 0.0001). Hemoglobin and absolute neutropenia were also substantially decreased at exit compared with screening, but this may be due to intensive blood sampling rather than direct effect of efavirenz on these parameters. No significant correlation was found between percent change in hemoglobin versus percent change in bilirubin, indicating the effect of efavirenz on bilirubin is independent of its effects on hemoglobin. CONCLUSIONS: Efavirenz monotherapy significantly lowers plasma total bilirubin concentration in healthy volunteers independent of its effect on hemoglobin, probably through its effects on bilirubin metabolism and transport (uptake and efflux). These findings help explain reversal by efavirenz of hyperbilirubinemia induction observed by some protease inhibitor antiretroviral drugs (eg, atazanavir). Besides its well-documented role on drug interactions, efavirenz may alter the disposition of endogenous compounds relevant in physiologic homeostasis through its interaction with drug metabolizing enzymes and/or drug transporters. ClinicalTrials.gov identifier: NCT00668395

Time to Treatment and Patient Outcomes among TB Suspects Screened by a Single Point-of-Care Xpert MTB/RIF at a Primary Care Clinic in Johannesburg, South Africa

In December 2010, the World Health Organization recommended a single Xpert MTB/RIF assay as the initial diagnostic in people suspected of HIV-associated or drug resistant tuberculosis. Few data are available on the impact of this recommendation on patient outcomes. We describe the diagnostic follow-up, clinical characteristics and outcomes of a cohort of tuberculosis suspects screened using a single point-of-care Xpert

Genome-wide Association Study of Susceptibility to Particulate Matter–Associated QT Prolongation

BACKGROUND: Ambient particulate matter (PM) air pollution exposure has been associated with increases in QT interval duration (QT). However, innate susceptibility to PM-associated QT prolongation has not been characterized. OBJECTIVE: To characterize genetic susceptibility to PM-associated QT prolongation in a multi-racial/ethnic, genome-wide association study (GWAS). METHODS: Using repeated electrocardiograms (1986–2004), longitudinal data on PM<10 μm in diameter (PM10), and generalized estimating equations methods adapted for low-prevalence exposure, we estimated approximately 2.5×106 SNP×PM10 interactions among nine Women’s Health Initiative clinical trials and Atherosclerosis Risk in Communities Study subpopulations (n=22,158), then combined subpopulation-specific results in a fixed-effects, inverse variance-weighted meta-analysis. RESULTS: A common variant (rs1619661; coded allele: T) significantly modified the QT-PM10 association (p=2.11×10−8). At PM10 concentrations >90th percentile, QT increased 7 ms across the CC and TT genotypes: 397 (95% confidence interval: 396, 399) to 404 (403, 404) ms. However, QT changed minimally across rs1619661 genotypes at lower PM10 concentrations. The rs1619661 variant is on chromosome 10, 132 kilobase (kb) downstream from CXCL12, which encodes a chemokine, stromal cell-derived factor 1, that is expressed in cardiomyocytes and decreases calcium influx across the L-type Ca2+ channel. CONCLUSIONS: The findings suggest that biologically plausible genetic factors may alter susceptibility to PM10-associated QT prolongation in populations protected by the U.S. Environmental Protection Agency’s National Ambient Air Quality Standards. Independent replication and functional characterization are necessary to validate our findings. https://doi.org/10.1289/EHP34

STROBE-X: X-ray Timing & Spectroscopy on Dynamical Timescales from Milliseconds to Years

We describe a probe-class mission concept that provides an unprecedented view of the X-ray sky, performing timing and 0.2-30 keV spectroscopy over timescales from microseconds to years. The Spectroscopic Time-Resolving Observatory for Broadband Energy X-rays (STROBE-X) comprises three primary instruments. The first uses an array of lightweight optics (3-m focal length) that concentrate incident photons onto solid state detectors with CCD-level (85-130 eV) energy resolution, 100 ns time resolution, and low background rates to cover the 0.2-12 keV band. This technology is scaled up from NICER [1], with enhanced optics to take advantage of the longer focal length of STROBE-X. The second uses large-area collimated silicon drift detectors, developed for ESA's LOFT [2], to cover the 2-30 keV band. These two instruments each provide an order of magnitude improvement in effective area compared with its predecessor (NICER and RXTE, respectively). Finally, a sensitive sky monitor triggers pointed observations, provides high duty cycle, high time resolution, high spectral resolution monitoring of the X-ray sky with approx. 20 times the sensitivity of the RXTE ASM, and enables multi-wavelength and multi-messenger studies on a continuous, rather than scanning basis. For the first time, the broad coverage provides simultaneous study of thermal components, non-thermal components, iron lines, and reflection features from a single platform for accreting black holes at all scales. The enormous collecting area allows detailed studies of the dense matter equation of state using both thermal emission from rotation-powered pulsars and harder emission from X-ray burst oscillations. The combination of the wide-field monitor and the sensitive pointed instruments enables observations of potential electromagnetic counterparts to LIGO and neutrino events. Additional extragalactic science, such as high quality spectroscopy of clusters of galaxies and unprecedented timing investigations of active galactic nuclei, is also obtaine