No abstract

Malaria burden on Bioko Island has decreased significantly over the past 15 years. The impact of interventions on malaria prevalence, however, has recently stalled. Here, we use data from island-wide, annual malaria indicator surveys to investigate human movement patterns and their relationship to Plasmodium falciparum prevalence. Using geostatistical and mathematical modelling, we find that off-island travel is more prevalent in and around the capital, Malabo. The odds of malaria infection among off-island travelers are significantly higher than the rest of the population. We estimate that malaria importation rates are high enough to explain malaria prevalence in much of Malabo and its surroundings, and that local transmission is highest along the West Coast of the island. Despite uncertainty, these estimates of residual transmission and importation serve as a basis for evaluating progress towards elimination and for efficiently allocating resources as Bioko makes the transition from control to elimination.

Hybridization has the potential to transfer beneficial alleles across species boundaries, and there are a growing number of examples in which this has apparently occurred. Recent studies suggest that Heliconius butterflies have transferred wing pattern mimicry alleles between species via hybridization, but ancestral polymorphism could also produce a signature of shared ancestry around mimicry genes. To distinguish between these alternative hypotheses, we measured DNA sequence divergence around putatively introgressed mimicry loci and compared this with the rest of the genome. Our results reveal that putatively introgressed regions show strongly reduced sequence divergence between co-mimetic species, suggesting that their divergence times are younger than the rest of the genome. This is consistent with introgression and not ancestral variation. We further show that this signature of introgression occurs at sites throughout the genome, not just around mimicry genes.

: As a first step in understanding structure and dynamics of white‐tailed deer (Odocoileus virginianus) populations, managers require knowledge of population size. Spotlight counts are widely used to index deer abundance; however, detection probabilities using spotlights have not been formally estimated. Using a closed mark—recapture design, we explored the efficiency of spotlights for detecting deer by operating thermal imagers and spotlights simultaneously. Spotlights detected only 50.6% of the deer detected by thermal imagers. Relative to the thermal imager, spotlights failed to detect 44.2% of deer groups (≥1 deer). Detection probabilities for spotlight observers varied between and within observers, ranging from 0.30 (SE = 0.053) to 0.66 (SE = 0.058). Managers commonly assume that although road counts based on convenience sampling designs are imperfect, observers can gather population‐trend information from repeated counts along the same survey route. Our results indicate detection rate varied between and within observers and surveyed transects. If detection probabilities are substantially affected by many variables, and if transect selection is not based on appropriate sampling designs, it may be impractical to correct road spotlight counts for detection probabilities to garner unbiased estimates of population size.

Objectives: To compare fixed epochs (FIXED) and rolling averages (ROLL) for quantifying worst-case scenario ('peak') running demands during professional soccer match-play, whilst assessing contextual influences.Design: Descriptive, observational.Methods: Twenty-five outfield players from an English Championship soccer club wore 10-Hz microelectromechanical systems during 28 matches. Relative total and high-speed (>5.5 m•s -1 ) distances were averaged over fixed and rolling 60-s to 600-s epochs. Linear mixed models compared FIXED versus ROLL and assessed the influence of epoch length, playing position, starting status, match result, location, formation, and time-of-day.Results: Irrespective of playing position or epoch duration, FIXED underestimated ROLL for total (~7-10%) and high-speed (~12-25%) distance. In ROLL, worst-case scenario relative total and high-speed distances reduced from 190.1±20.4 m•min -1 and 59.5±23.0 m•min -1 in the 60-s epoch, to 120.9±13.1 m•min -1 and 14.2±6.5 m•min -1 in the 600-s epoch, respectively. Worst-case scenario total distance was higher for midfielders (~9-16 m•min -1 ) and defenders (~3-10 m•min -1 ) compared with attackers. In general, starters experienced higher worst-case scenario total distance than substitutes (~3.6-8.5 m•min -1 ), but lower worst-case scenario high-speed running over 300-s (~3 m•min -1 ). Greater worst-case scenario total and high-speed distances were elicited during wins (~7.3-11.2 m•min -1 and ~2.7-7.9 m•min -1 , respectively) and losses (~2.7-5.7 m•min -1 and ~1.4-2.2 m•min -1 , respectively) versus draws, whilst time-of-day and playing formation influenced worst-case scenario high-speed distances only.Conclusions: These data indicate an underestimation of worst-case scenario running demands in FIXED versus ROLL over 60-s to 600-s epochs while highlighting situational influences. Such information facilitates training specificity by enabling sessions to be targeted at the most demanding periods of competition.

The haplotypes of a beneficial allele carry information about its history that can shed light on its age and the putative cause for its increase in frequency. Specifically, the signature of an allele’s age is contained in the pattern of variation that mutation and recombination impose on its haplotypic background. We provide a method to exploit this pattern and infer the time to the common ancestor of a positively selected allele following a rapid increase in frequency. We do so using a hidden Markov model which leverages the length distribution of the shared ancestral haplotype, the accumulation of derived mutations on the ancestral background, and the surrounding background haplotype diversity. Using simulations, we demonstrate how the inclusion of information from both mutation and recombination events increases accuracy relative to approaches that only consider a single type of event. We also show the behavior of the estimator in cases where data do not conform to model assumptions, and provide some diagnostics for assessing and improving inference. Using the method, we analyze population-specific patterns in the 1000 Genomes Project data to estimate the timing of adaptation for several variants which show evidence of recent selection and functional relevance to diet, skin pigmentation, and morphology in humans.

No abstract

2002. Stable carbon and oxygen isotopic evidence for late Pleistocene to middle Holocene climatic fluctuations in the interior of southern Africa.ABSTRACT: Stable carbon and oxygen isotope analyses of ungulate grazers from four archaeological sites located in different environs within the Caledon River Valley have provided a relatively well-dated proxy palaeoenvironmental and palaeoclimatic sequence for the period between 16 000 and 6000 calendar (cal.) yr BP. Within the overall trend towards hot mid-Holocene temperatures and a summer rainfall pattern, stable carbon isotope results show that there were three periods when growth season temperatures were cool enough for C 3 grasses to be present: 16 000-14 000; 10 200-9600, and 8400-8000 cal. yr BP. Similar trends were recorded in stable oxygen isotope values, reflecting shifts in either temperature or available moisture. Although having a similar pattern to that of the lower altitude site, sites situated in foothills and montane portions of the valley consistently maintained lower temperatures until the mid-Holocene altithermal. At this time growth season temperatures warmed sufficiently for a 100% C 4 grassland to expand in altitude from the warmer low lying localities. In relation to present understanding of synoptic and global climatic patterning, these findings suggest that the early to middle Holocene transition was not a gradual warming trend, but rather it was marked by a series of climatic fluctuations. Of particular note is the possible global, rather than regional, occurrence of the 8200 cal. yr BP 'event'.