Optimal Hematocrit: Theory, Regulation and Implications

SYNOPSIS. Hematocrit is likely to be optimized because of itsinfluences on oxygen transport. However, optimal hematocritmust also change because shear rates and blood vessel radiiwithin circulations change temporally. Blood vessel endotheliaregulate shear stress on their walls by changing their radius.Wall shear stress is dependent on shear rate and viscosity.Because there is regulation of vessel radius by the endotheliumit is hypothesized that hematocrit may be regulated near optimalby changes in plasma volume. The implication of such regulationis that changes in vascular volume (blood volume) would occurwith alterations in red blood cell mass. Data are presentedwhich indicate that regulation of optimal hematocrit normallyoccurs through changes in plasma volume. The regulation of optimalhematocrit has significant implications for processes that dependon oxygen transport (e.g., exercise) because of the effect ofblood volume on cardiac output.     

Ecomigration and Violent Conflict: Case Studies and Public Policy Implications

In 2005, a hurricane named Katrina hit the states of Louisiana and Mississippi in the US, destroying properties and flooding areas. Many people left the region and still have not returned. While some of these people may eventually return, some may not, becoming “migrants.” Assuming this phenomenon will occur, is it unique? What is the role of the environment in migration? Can there be violent conflict between such migrants and residents in areas absorbing migrants? We evaluate these questions in the cases of Hurricane Katrina, the US Dust Bowl in the 1930s, and Bangladesh since the 1950s, demonstrating that environmental change can trigger large out-migration, which can cause violent conflict in areas receiving migrants. These findings have important policy implications. Climate change is expected to degrade the environment considerably in this century. Minimizing climate change-induced migration and violent conflict in receiving areas requires an engineered economic slowdown in the developed countries, and population stabilization and economic growth in the developing countries financed by the developed countries.     

Clearcutting Maine: Implications for the Theory of Common Property Resources

One of the basic tenets of the theory of common property resources is that private property rights work to conserve natural resources. There is growing evidence, however, that some large forest owners in Maine are cutting their forests heavily, using poor-quality silviculture techniques. This overexploitation is being done by paper companies, forest contractors, and some private land owners, who are being motivated by very different sets of factors. This article explores the reasons that private owners of forest resources are overexploiting their own lands and the implications of this for the theory of common property resources. Secure private property rights alone will not be enough to conserve resources and do away with externalities when the owners are operating in a system demanding constant short-term profits, where they are producing undifferentiated commodities in a highly competitive market, where the future value of slow-growing resources is very low, and where harvesting has so many ramifying biological and social effects.     

Some Implications of Clark Wissler's Race Theory

A recent attempt to place the name of Clark Wissler in a central position in the history of anthropology ignores his blatant racism. Wissler's racism was evident not only in scholarly and popular circles, but, as well, was employed by the United States government to give ‘scientific’ status to its Immigration Act of 1924. The Act favoured the inflow of Northwest Europeans at the expense of Eastern European Jews and other groups who had been immigrating in massive numbers, and whose presence had become increasingly unwelcome. It was used by the Nazi propaganda machine to justify German anti-Semitism in 1933 and thereafter, and by the United States Department of State to turn away the eventual victims of Nazi genocide. Wissler thus provides a profound scholarly and human contrast to Franz Boas, who publicly deplored racism and immigration restriction. Boas' stand as a ‘citizen-scientist’ partly accounts for his under-evaluation by later anthropologists, most recently by Derek Freeman in his Margaret Mead and Samoa.     

Fuelwood Use and Availability in Bhutan: Implications for National Policy and Local Forest Management

Fuelwood is the principal energy resource for millions of households around the world, yet its use, availability and management remain poorly understood in many areas. We document fuelwood consumption, growth/yield and standing biomass in a Bhutanese village and alpine area used seasonally by villagers where the government is concerned about harvesting in a recently designated national park. Pinus wallichiana was the only fuelwood used in the village and assessments suggest 52 ha could sustain local needs at current consumption levels (54 m3/household/yr). In contrast, Rhododendron aeruginosum was used in the alpine site and at current consumption rates all will be consumed by 2023. Our findings emphasize the need to manage fuelwood based on site-specific consumption, growth and standing biomass criteria rather than single, nation-wide regulations. We provide methods to develop sustainable fuelwood harvesting and forest management guidelines that are applicable to government and community-managed forests in Bhutan and elsewhere.     

Punishment as a Means of Competition: Implications for Strong Reciprocity Theory

Strong negative reciprocity, that is, sanctions imposed on norm violators at the punisher’s own expense, has powerful cooperation-enhancing effects in both real-life and experimental game situations. However, it is plausible that punishment may obtain alternative roles depending on social context and the personality characteristics of participants. We examined the occurrence of punishing behavior among 80 subjects in a strongly competitive Public Goods game setting. Despite the punishment condition, the amount of the contributions decreased steadily during the game. The amount of contributions had no significant effect on received and imposed punishments. The results indicate that certain social contexts (in this case, intensive competition) exert modifying effects on the role that punishment takes on. Subjects punished each other in order to achieve a higher rank and a financially better outcome. Punishment primarily functioned as a means of rivalry, instead of as a way of second-order cooperation, as strong reciprocity suggests. These results indicate the need for the possible modification of the social conditions of punishment mechanisms described by the strong reciprocity theory as an evolutionary explanation of human cooperation.     

Sexual Behavior among Persons Living with HIV in Uganda: Implications for Policy and Practice

Introduction

HIV epidemics are sustained and propagated by new cases of infection which result from transmission from infected persons to uninfected susceptible individuals. People living with HIV (PLHIV) play a critical role in prevention if they adopt safer sexual behaviors. This study estimated the prevalence of and factors associated with safer sexual behaviors among PLHIV seeking care from civil society organizations (CSOs).

Methods

In a cross sectional study PLHIV were interviewed about their sexual practices, use of alcohol, HIV status of their regular sexual partners, desire for more children and about their socio-demographic characteristics. We calculated the proportion of PLHIV who abstained and consistently used condoms in the previous twelve months. Independent associations between safer sex and other variables were estimated using adjusted prevalence ratios (aPR) and their 95% confidence intervals (CI).

Results

Of the 939 PLHIV, 54% (508) were either abstaining or using condoms consistently and 291 (31%) desired more children. The prevalence of consistent condom use among the sexually active was 41.3% (300/731). Consistent condom use was higher among PLHIV who: didn''t use alcohol (aPR 1.30, CI 1.03–1.63); were educated about re-infection with a new strain of HIV (aPR 1.84, CI 1.08–3.12) and had regular sexual partner who was HIV negative (aPR 1.29, CI 1.05–1.57). Prevalence of abstinence was 22.2% (208/939). Abstinence increased with age from 9.4% among PLHIV <25 years to 40.5% among those >50 years. Abstinence was extremely low (2.5%) among PLHIV who were married.

Conclusions

Effective interventions that reduce alcohol consumption among PLHIV are needed to avert HIV transmission, prevent acquisition of new HIV strains and STIs. In addition, strategies are needed to address needs of PLHIV who desire more children.     

The Sanctification of Dreams: Prevalence and Implications

Many scientists and practitioners have debated about the function of dreams. Though some researchers have described dreams as purposeless random neuronal firings, others have suggested that dreams serve an adaptive function with certain dream characteristics having positive implications. Drawing on other studies of sanctification, this study examines whether imbuing a dream with qualities of the sacred relates to beneficial outcomes. Examining a college student sample of 168, it was found that the more sacred the dream was perceived, the more beneficial the outcome reported from a stressful life event which related to the dream. These outcomes include less negative affect and more positive affect, psychological and spiritual growth. Sanctification of dreams predicted these outcome variables over and above other religious measures as well as dream measures. The implications of these findings are discussed.     

Chlamydia trachomatis Load in Population-Based Screening and STI-Clinics: Implications for Screening Policy

Objectives

If the Chlamydia trachomatis (CT) bacterial load is higher in high-risk populations than in the general population, this negatively affects the efficacy of CT screening incentives. In the largest retrospective study to date, we investigated the CT load in specimens collected from 2 cohorts: (1) attendants of a sexually transmitted infection (STI)-clinic and (2) participants of the Dutch population-based screening (PBS).

Methods

CT load was determined using quantitative PCR in CT-positive male urine and female cervicovaginal swabs. CT loads were converted into tertiles. Using multinominal logistic regression, independent association of cohort, symptoms, risk behaviour and human cell count on load were assessed.

Results

CT loads were determined in 889 CT-positives from PBS (n = 529; 71.8% female) and STI-clinics (n = 360; 61.7% female). In men, STI-clinic-cohort, human cell count and urethral discharge were positively associated with CT load. In women, PBS-cohort and cell count were positively associated with CT load. Both cohorts had the same range in CT load.

Conclusions

The general population has a similar range of bacterial CT load as a high-risk population, but a different distribution for cohort and gender, highlighting the relevance of population-based CT-screening. When CT loads are similar, possibly the chances of transmission and sequelae are too.     

Implications of an Absolute Simultaneity Theory for Cosmology and Universe Acceleration

An alternate Lorentz transformation, Absolute Lorentz Transformation (ALT), has similar kinematics to special relativity yet maintains absolute simultaneity in the context of a preferred reference frame. In this study, it is shown that ALT is compatible with current experiments to test Lorentz invariance only if the proposed preferred reference frame is locally equivalent to the Earth-centered non-rotating inertial reference frame, with the inference that in an ALT framework, preferred reference frames are associated with centers of gravitational mass. Applying this theoretical framework to cosmological data produces a scenario of universal time contraction in the past. In this scenario, past time contraction would be associated with increased levels of blueshifted light emissions from cosmological objects when viewed from our current perspective. The observation that distant Type Ia supernovae are dimmer than predicted by linear Hubble expansion currently provides the most direct evidence for an accelerating universe. Adjusting for the effects of time contraction on a redshift–distance modulus diagram produces a linear distribution of supernovae over the full redshift spectrum that is consistent with a non-accelerating universe.