The strength and timing of the mitochondrial bottleneck in salmon suggests a conserved mechanism in vertebrates

In most species mitochondrial DNA (mtDNA) is inherited maternally in an apparently clonal fashion, although how this is achieved remains uncertain. Population genetic studies show not only that individuals can harbor more than one type of mtDNA (heteroplasmy) but that heteroplasmy is common and widespread across a diversity of taxa. Females harboring a mixture of mtDNAs may transmit varying proportions of each mtDNA type (haplotype) to their offspring. However, mtDNA variants are also observed to segregate rapidly between generations despite the high mtDNA copy number in the oocyte, which suggests a genetic bottleneck acts during mtDNA transmission. Understanding the size and timing of this bottleneck is important for interpreting population genetic relationships and for predicting the inheritance of mtDNA based disease, but despite its importance the underlying mechanisms remain unclear. Empirical studies, restricted to mice, have shown that the mtDNA bottleneck could act either at embryogenesis, oogenesis or both. To investigate whether the size and timing of the mitochondrial bottleneck is conserved between distant vertebrates, we measured the genetic variance in mtDNA heteroplasmy at three developmental stages (female, ova and fry) in chinook salmon and applied a new mathematical model to estimate the number of segregating units (N(e)) of the mitochondrial bottleneck between each stage. Using these data we estimate values for mtDNA Ne of 88.3 for oogenesis, and 80.3 for embryogenesis. Our results confirm the presence of a mitochondrial bottleneck in fish, and show that segregation of mtDNA variation is effectively complete by the end of oogenesis. Considering the extensive differences in reproductive physiology between fish and mammals, our results suggest the mechanism underlying the mtDNA bottleneck is conserved in these distant vertebrates both in terms of it magnitude and timing. This finding may lead to improvements in our understanding of mitochondrial disorders and population interpretations using mtDNA data

Barriers to Offering Vasectomy at Publicly Funded Family Planning Organizations in Texas

Few publicly funded family planning clinics in the United States offer vasectomy, but little is known about the reasons this method is not more widely available at these sources of care. Between February 2012 and February 2015, three waves of in-depth interviews were conducted with program administrators at 54 family planning organizations in Texas. Participants described their organization’s vasectomy service model and factors that influenced how frequently vasectomy was provided. Interview transcripts were coded and analyzed using a theme-based approach. Service models and barriers to providing vasectomy were compared by organization type (e.g., women’s health center, public health clinic) and receipt of Title X funding. Two thirds of organizations did not offer vasectomy on-site or pay for referrals with family planning funding; nine organizations frequently provided vasectomy. Organizations did not widely offer vasectomy because they could not find providers that would accept the low reimbursement for the procedure or because they lacked funding for men’s reproductive health care. Respondents often did not perceive men’s reproductive health care as a service priority and commented that men, especially Latinos, had limited interest in vasectomy. Although organizations of all types reported barriers, women’s health centers and Title X-funded organizations more frequently offered vasectomy by conducting tailored outreach to men and vasectomy providers. A combination of factors operating at the health systems and provider level influence the availability of vasectomy at publicly funded family planning organizations in Texas. Multilevel approaches that address key barriers to vasectomy provision would help organizations offer comprehensive contraceptive services.Population Research Cente

Hypertension among Oral Contraceptive Users in El Paso, Texas

On the U.S.-Mexico border, residents frequently cross into Mexico to obtain medications or medical care. We previously reported relatively high prevalence of hypertension among Latina oral contraceptive users in El Paso, particularly those obtaining pills over the counter (OTC) in Mexico. Here, we examine factors associated with having hypertension among 411 OTC users and 399 clinic users. We also assess hypertension awareness and interest in using blood pressure kiosks. Women age 35 to 44 and who had BMI ≥ 30 kg/m2 had higher odds of having hypertension. 59% of hypertensive women had unrecognized hypertension, and 77% of all participants would use a blood pressure kiosk; there were no significant differences between clinic and OTC users. Alternative approaches to increase access to health screenings are needed in this setting, where OTC pill use among women with unrecognized hypertension confers unique health risksPopulation Research Cente

The Impact of Information about Abortion Safety on Texas Voters’ Opinions about Restrictive Laws

A substantial gap exists between the scientific evidence demonstrating the safety of abortion in the United States and public opinion about abortion safety. But recent studies suggest that it may be possible to change perceptions about health issues that are based on misinformation. This brief, by researchers from the Texas Policy Evaluation Project, demonstrates that informational statements about the safety of office-based abortion care as currently practiced in Texas significantly reduced perceptions that ambulatory surgical center and admitting privileges requirements would make abortion safer and reduced support for these requirements.Population Research Cente

Particle Astrophysics and Cosmology: Cosmic Laboratories for New Physics (Summary of the Snowmass 2001 P4 Working Group)

The past few years have seen dramatic breakthroughs and spectacular and puzzling discoveries in astrophysics and cosmology. In many cases, the new observations can only be explained with the introduction of new fundamental physics. Here we summarize some of these recent advances. We then describe several problem in astrophysics and cosmology, ripe for major advances, whose resolution will likely require new physics.Comment: 27 pages, 14 figure

The Economics of Efficient Phosphorus Abatement in a Watershed

This study presents a method to determine efficient environmental targets at a watershed level. Efficient targets are devised by estimating abatement cost and cost of environmental damages and minimizing their sum. The method was applied to a case study of phosphorus pollution in a watershed in Oklahoma. Several cumulative scenarios with alternative abatement options were simulated and efficient targets were determined. As the number of abatement options at disposal to agricultural sources increased, their optimal abatement expanded relative to the abatement at the point source. Efficient targets were found to be dependent on the choice of policy that stimulates abatement.efficiency, environmental targets, phosphorus pollution, watershed, Resource /Energy Economics and Policy,

Economic Analysis of Management Practices to Reduce Phosphorus Load to Lake Eucha and Spavinaw

Changes in management practices are often proposed to reduce phosphorus loading from a watershed due to over application of poultry litter. This study determines the choice, location, and level of each best management practice in the watershed to meet a Total Maximum Daily Load and margins of safety at least cost.best management practice, phosphorus runoff, poultry litter, Target MOTAD, Environmental Economics and Policy,

Theoretical uncertainty in baryon oscillations

We discuss the systematic uncertainties in the recovery of dark energy properties from the use of baryon acoustic oscillations as a standard ruler. We demonstrate that while unknown relativistic components in the universe prior to recombination would alter the sound speed, the inferences for dark energy from low-redshift surveys are unchanged so long as the microwave background anisotropies can measure the redshift of matter-radiation equality, which they can do to sufficient accuracy. The mismeasurement of the radiation and matter densities themselves (as opposed to their ratio) would manifest as an incorrect prediction for the Hubble constant at low redshift. In addition, these anomalies do produce subtle but detectable features in the microwave anisotropies.Comment: 4 pages, REVTeX, 1 figure. Submitted to PR