Working at the interface of phylogenetics and population genetics: a biogeographical analysis of Triaenops spp. (Chiroptera: Hipposideridae).

New applications of genetic data to questions of historical biogeography have revolutionized our understanding of how organisms have come to occupy their present distributions. Phylogenetic methods in combination with divergence time estimation can reveal biogeographical centres of origin, differentiate between hypotheses of vicariance and dispersal, and reveal the directionality of dispersal events. Despite their power, however, phylogenetic methods can sometimes yield patterns that are compatible with multiple, equally well-supported biogeographical hypotheses. In such cases, additional approaches must be integrated to differentiate among conflicting dispersal hypotheses. Here, we use a synthetic approach that draws upon the analytical strengths of coalescent and population genetic methods to augment phylogenetic analyses in order to assess the biogeographical history of Madagascar's Triaenops bats (Chiroptera: Hipposideridae). Phylogenetic analyses of mitochondrial DNA sequence data for Malagasy and east African Triaenops reveal a pattern that equally supports two competing hypotheses. While the phylogeny cannot determine whether Africa or Madagascar was the centre of origin for the species investigated, it serves as the essential backbone for the application of coalescent and population genetic methods. From the application of these methods, we conclude that a hypothesis of two independent but unidirectional dispersal events from Africa to Madagascar is best supported by the data.

Making it in the Modern Job Market: A Study of Communication among the Deaf and Hard of Hearing Population

Gemstone Team AUDIO (Assessing and Understanding Deaf Individuals' Occupations)

The impact of host immune status on the within-host and population dynamics of antigenic immune escape.

Antigenically evolving pathogens such as influenza viruses are difficult to control owing to their ability to evade host immunity by producing immune escape variants. Experimental studies have repeatedly demonstrated that viral immune escape variants emerge more often from immunized hosts than from naive hosts. This empirical relationship between host immune status and within-host immune escape is not fully understood theoretically, nor has its impact on antigenic evolution at the population level been evaluated. Here, we show that this relationship can be understood as a trade-off between the probability that a new antigenic variant is produced and the level of viraemia it reaches within a host. Scaling up this intra-host level trade-off to a simple population level model, we obtain a distribution for variant persistence times that is consistent with influenza A/H3N2 antigenic variant data. At the within-host level, our results show that target cell limitation, or a functional equivalent, provides a parsimonious explanation for how host immune status drives the generation of immune escape mutants. At the population level, our analysis also offers an alternative explanation for the observed tempo of antigenic evolution, namely that the production rate of immune escape variants is driven by the accumulation of herd immunity. Overall, our results suggest that disease control strategies should be further assessed by considering the impact that increased immunity--through vaccination--has on the production of new antigenic variants.

Patient-provider communication, self-reported medication adherence, and race in a postmyocardial infarction population.

OBJECTIVES: Our objectives were to: 1) describe patient-reported communication with their provider and explore differences in perceptions of racially diverse adherent versus nonadherent patients; and 2) examine whether the association between unanswered questions and patient-reported medication nonadherence varied as a function of patients' race. METHODS: We conducted a cross-sectional analysis of baseline in-person survey data from a trial designed to improve postmyocardial infarction management of cardiovascular disease risk factors. RESULTS: Overall, 298 patients (74%) reported never leaving their doctor's office with unanswered questions. Among those who were adherent and nonadherent with their medications, 183 (79%) and 115 (67%) patients, respectively, never left their doctor's office with unanswered questions. In multivariable logistic regression, although the simple effects of the interaction term were different for patients of nonminority race (odds ratio [OR]: 2.16; 95% confidence interval [CI]: 1.19-3.92) and those of minority race (OR: 1.19; 95% CI: 0.54-2.66), the overall interaction effect was not statistically significant (P=0.24). CONCLUSION: The quality of patient-provider communication is critical for cardiovascular disease medication adherence. In this study, however, having unanswered questions did not impact medication adherence differently as a function of patients' race. Nevertheless, there were racial differences in medication adherence that may need to be addressed to ensure optimal adherence and health outcomes. Effort should be made to provide training opportunities for both patients and their providers to ensure strong communication skills and to address potential differences in medication adherence in patients of diverse backgrounds.

A population model of folate-mediated one-carbon metabolism.

BACKGROUND: Previous mathematical models for hepatic and tissue one-carbon metabolism have been combined and extended to include a blood plasma compartment. We use this model to study how the concentrations of metabolites that can be measured in the plasma are related to their respective intracellular concentrations. METHODS: The model consists of a set of ordinary differential equations, one for each metabolite in each compartment, and kinetic equations for metabolism and for transport between compartments. The model was validated by comparison to a variety of experimental data such as the methionine load test and variation in folate intake. We further extended this model by introducing random and systematic variation in enzyme activity. OUTCOMES AND CONCLUSIONS: A database of 10,000 virtual individuals was generated, each with a quantitatively different one-carbon metabolism. Our population has distributions of folate and homocysteine in the plasma and tissues that are similar to those found in the NHANES data. The model reproduces many other sets of clinical data. We show that tissue and plasma folate is highly correlated, but liver and plasma folate much less so. Oxidative stress increases the plasma S-adenosylmethionine/S-adenosylhomocysteine (SAM/SAH) ratio. We show that many relationships among variables are nonlinear and in many cases we provide explanations. Sampling of subpopulations produces dramatically different apparent associations among variables. The model can be used to simulate populations with polymorphisms in genes for folate metabolism and variations in dietary input.

Future requirements for and supply of ophthalmologists for an aging population in Singapore.

BACKGROUND: Singapore's population, as that of many other countries, is aging; this is likely to lead to an increase in eye diseases and the demand for eye care. Since ophthalmologist training is long and expensive, early planning is essential. This paper forecasts workforce and training requirements for Singapore up to the year 2040 under several plausible future scenarios. METHODS: The Singapore Eye Care Workforce Model was created as a continuous time compartment model with explicit workforce stocks using system dynamics. The model has three modules: prevalence of eye disease, demand, and workforce requirements. The model is used to simulate the prevalence of eye diseases, patient visits, and workforce requirements for the public sector under different scenarios in order to determine training requirements. RESULTS: Four scenarios were constructed. Under the baseline business-as-usual scenario, the required number of ophthalmologists is projected to increase by 117% from 2015 to 2040. Under the current policy scenario (assuming an increase of service uptake due to increased awareness, availability, and accessibility of eye care services), the increase will be 175%, while under the new model of care scenario (considering the additional effect of providing some services by non-ophthalmologists) the increase will only be 150%. The moderated workload scenario (assuming in addition a reduction of the clinical workload) projects an increase in the required number of ophthalmologists of 192% by 2040. Considering the uncertainties in the projected demand for eye care services, under the business-as-usual scenario, a residency intake of 8-22 residents per year is required, 17-21 under the current policy scenario, 14-18 under the new model of care scenario, and, under the moderated workload scenario, an intake of 18-23 residents per year is required. CONCLUSIONS: The results show that under all scenarios considered, Singapore's aging and growing population will result in an almost doubling of the number of Singaporeans with eye conditions, a significant increase in public sector eye care demand and, consequently, a greater requirement for ophthalmologists.

Preliminary studies on the effect of the increased biodiversity on the population dynamics of Caliroa cerasi L. (Hymenoptera: Tenthredinidae), and its natural enemy Trichogramma minutum R. (Hymenoptera: Trichogrammatidae) in a sweet cherry (Prunus avium L.) orchard in Virch (Southern Patagonia Argentina)

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Preliminary studies on the effect of the increased biodiversity on the population dynamics of Caliroa cerasi L. (Hymenoptera: Tenthredinidae), and its natural enemy Trichogramma minutum R. (Hymenoptera: Trichogrammatidae) in a sweet cherry (Prunus avium L.) orchard in Virch (Southern Patagonia Argentina)

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Health status of an elderly population in Sharpeville, South Africa

The objective of this cross-sectional study was a comprehensive nutrition and health assessment to provide a basis for future intervention strategies for an elderly population attending a day-care centre. Socio-demographic, health and 24-hour recall dietary intake questionnaires were administered and anthropometric and biochemical measurements taken. The results indicate that the majority of respondents had an income of between R501 and R1 000 (South African rand) per month and most of them reported an occasional lack of funds to meet basic household needs, confirming the presence of food insecurity. Daily dietary intakes (mean [+ or -] Standard Deviation [SD]) of the women were 5 395 [+ or -] 2 946 kJ energy, 47 [+ or -] 27 g protein, 28 [+ or -] 21 g fat and 196 [+ or -] 123 g carbohydrates compared to 8 641 [+ or -] 3 799 kJ, 86 [+ or -] 48 g, 49 [+ or -] 32 g and 301 [+ or -] 139 g of the men, respectively. The majority (83.6%) of the women were overweight (body mass index [BMI] [greater than or equal to] 25) or obese (BMI [greater than or equal to] 30) whilst 78% had a mid-upper arm circumference (MUAC) of [greater than or equal to] 21.7 cm. Mean intakes of micronutrients were low in comparison to reference standards and serum zinc levels were suboptimal. Obesity, hypertension and raised total serum cholesterol levels indicated an increased risk for coronary heart disease. It can be concluded that a low income, household food insecurity and risk factors associated with malnutrition and non-communicable diseases were prevalent in this elderly population. OPSOMMING Die doelwit van hierdie dwarssnitstudie was ‘n omvattende bepaling van voeding- en gesondheidstatus om as basis te dien vir toekomstige intervensiestrategieë vir ’n groep bejaardes wat ’n dagsentrum besoek. Sosiodemografiese, gesondheid- en 24-uur herroep-dieetinname vraelyste is voltooi en antropometriese en biochemiese metings is geneem. Die resultate het bevestig dat die meerderheid respondente ‘n maandelikse inkomste van tussen R501 en R1 000 (Suid-Afrikaanse rand) gehad het. Die meeste het ‘n geldtekort vir basiese huishoudelike behoeftes gerapporteer wat dui op huishoudelike voedselinsekuriteit. Daaglikse dieetinnames (gemiddeld±standaardafwyking [SA]) van die vroue was onderskeidelik 5 395±2 946 kJ energie, 47±27 g proteïen, 28±21 g vet en 196±123 g koolhidrate in vergelyking met 8 641±3 799 kJ, 86±48 g, 49±32 g en 301±139 g vir die mans. Die meerderheid (83.6%) van die vroue was oorgewig (liggaamsmassa-indeks [LMI] >25) of vetsugtig (LMI > 30) en 78% het ’n middel-bo-armomtrek (MUAC) van > 21.7 cm gehad. Gemiddelde mikronutriëntinnames was laag in vergelyking met die verwysingstandaarde en serumsink was suboptimaal. Vetsug, hipertensie en verhoogde totale serumcholesterolvlakke het op ‘n verhoogde risiko van kardiovaskulêre siekte gedui. Die resultate het dus bewys dat lae inkomste, huishoudelike voedselinsekuriteit en die risikofaktore wat met wanvoeding en leefstylsiektes geassosieer word, teenwoordig was.

PCR from the CPR offers a historical perspective on marine population ecology.

The Continuous Plankton Recorder (CPR) survey has collected plankton samples from regular tracks across the world's oceans for almost 70 y. Over 299,000 spatially extensive CPR samples are archived and stored in buffered formalin. This CPR archive offers huge potential to study changes in marine communities using molecular data from a period when marine pollution, exploitation and global anthropogenic impact were much less pronounced. However, to harness the amount of data available within the CPR archive fully, it is necessary to improve techniques of larval identification, to genus and species preferably, and to obtain genetic information for historical studies of population ecology. To increase the potential of the CPR database this paper describes the first extraction, amplification by the polymerase chain reaction and utilization of a DNA sequence (mitochondrial 16S rDNA) from a CPR sample, a formalin fixed larval sandeel.