Modeling growth of mandibles in the Western Arctic caribou herd

We compared growth curves for ramus length and diastema length from two autumn collections of mandibles of male Western Arctic Herd caribou in Alaska. We were primarily interested in determining if growth curves of caribou mandibles differed between caribou born during 1959-1967, after the herd had been high for several years and was probably declining in size, and those born during 1976-1988, when the herd was increasing in size. To compare these growth curves, we used a nonlinear model and used maximum likelihood estimates and likelihood ratio tests. We found that growth rates were similar between periods, but intercepts and variances of growth curves differed. From this we infer that calves were smaller in autumn during the 1960s and that significant compensatory growth did not occur later in life

Redistribution of Calving Caribou in Response to Oil Field Development on the Arctic Slope of Alaska

Aerial surveys were conducted annually in June 1978-87 near Prudhoe Bay, Alaska, to determine changes in the distribution of calving caribou (Rangifer tarandus granti) that accompanied petroleum-related development. With construction of an oil field access road through a calving concentration area, mean caribou density (no./sq. km) decreased from 1.41 to 0.31 (P=0.05) with 1 km and increased from 1.41 to 4.53 (P=0.04) 5-6 km from the road. Concurrently, relative caribou use of the adjacent area declined (P<0.02), apparently in response to increasing surface development. We suggest that perturbed distribution associated with roads reduced the capacity of the nearby area to sustain parturient females and that insufficient spacing of roads may have depressed overall calving activity. Use of traditional calving grounds and of certain areas therein appears to favor calf survival, principally through lower predation risk and improved foraging conditions. Given the possible loss of those habitats through displacement and the crucial importance of the reproductive process, a cautious approach to petroleum development on the Arctic Slope is warranted.Key words: Alaska, calving, caribou, disturbance, oil fieldRÉSUMÉ. Des photographies aériennes ont été prises au mois de juin chaque année de 1978 à 1987 près de la baie Prudhoe en Alaska, en vue de déterminer les changements dans la distribution des caribous (Rangifer tarandus granti) qui mettaient bas, changements accompagnant les projets de mise en valeur reliés au pétrole. Avec la construction d’une route d’accès à un champ pétrolifère à travers une zone importante de mise bas, la densité moyenne du caribou (nombre d’individus/km2) diminuait de 1,41 à 0,31 (P = 0,OS) à moins d’1 km de la route et augmentait de 1,41 à 4,53 (P = 0,04) à une distance de 516 km de la route. En même temps, l’utilisation relative de la zone adjacente par le caribou diminuait (P < 0,02), apparemment enréponse à l’augmentation de la mise en valeur de surface. On suggère que la perturbation de la distribution associée à la construction de routes diminuait la capacité de la zone environnante à supporter des femelles parturientes et qu’un espacement insuffisant des routes aurait pu faire chuter l’activité générale de mise bas. L’utilisation de terrains traditionnels de mise bas ainsi que de certaines zones à l’intérieur de ces terrains semble favoriser la survie des veaux, en particulier grâce à une baisse de la prédation et à de meilleures conditions de pâturage. Étant donné que le caribou pourrait être évincé de cet habitat et vu l’importance cruciale du processus de reproduction, on recommande une approche prudente à l’exploitation du pétrole sur le versant arctique.Mots clés: Alaska, mise bas, caribou, perturbation, champ pétrolifèr

Heteroepitaxial growth of ferromagnetic MnSb(0001) films on Ge/Si(111) virtual substrates

Molecular beam epitaxial growth of ferromagnetic MnSb(0001) has been achieved on high quality, fully relaxed Ge(111)/Si(111) virtual substrates grown by reduced pressure chemical vapor deposition. The epilayers were characterized using reflection high energy electron diffraction, synchrotron hard X-ray diffraction, X-ray photoemission spectroscopy, and magnetometry. The surface reconstructions, magnetic properties, crystalline quality, and strain relaxation behavior of the MnSb films are similar to those of MnSb grown on GaAs(111). In contrast to GaAs substrates, segregation of substrate atoms through the MnSb film does not occur, and alternative polymorphs of MnSb are absent

May Measurement Month 2018: a pragmatic global screening campaign to raise awareness of blood pressure by the International Society of Hypertension

Aims Raised blood pressure (BP) is the biggest contributor to mortality and disease burden worldwide and fewer than half of those with hypertension are aware of it. May Measurement Month (MMM) is a global campaign set up in 2017, to raise awareness of high BP and as a pragmatic solution to a lack of formal screening worldwide. The 2018 campaign was expanded, aiming to include more participants and countries. Methods and results Eighty-nine countries participated in MMM 2018. Volunteers (≥18 years) were recruited through opportunistic sampling at a variety of screening sites. Each participant had three BP measurements and completed a questionnaire on demographic, lifestyle, and environmental factors. Hypertension was defined as a systolic BP ≥140 mmHg or diastolic BP ≥90 mmHg, or taking antihypertensive medication. In total, 74.9% of screenees provided three BP readings. Multiple imputation using chained equations was used to impute missing readings. 1 504 963 individuals (mean age 45.3 years; 52.4% female) were screened. After multiple imputation, 502 079 (33.4%) individuals had hypertension, of whom 59.5% were aware of their diagnosis and 55.3% were taking antihypertensive medication. Of those on medication, 60.0% were controlled and of all hypertensives, 33.2% were controlled. We detected 224 285 individuals with untreated hypertension and 111 214 individuals with inadequately treated (systolic BP ≥ 140 mmHg or diastolic BP ≥ 90 mmHg) hypertension. Conclusion May Measurement Month expanded significantly compared with 2017, including more participants in more countries. The campaign identified over 335 000 adults with untreated or inadequately treated hypertension. In the absence of systematic screening programmes, MMM was effective at raising awareness at least among these individuals at risk

Modeling auditory evoked brainstem responses to transient stimuli

A quantitative model is presented that describes the formation of auditory brainstem responses (ABRs) to tone pulses, clicks, and rising chirps as a function of stimulation level. The model computes the convolution of the instantaneous discharge rates using the “humanized” nonlinear auditory-nerve model of Zilany and Bruce [J. Acoust. Soc. Am. 122, 402–417 (2007)] and an empirically derived unitary response function which is assumed to reflect contributions from different cell populations within the auditory brainstem, recorded at a given pair of electrodes on the scalp. It is shown that the model accounts for the decrease of tone-pulse evoked wave-V latency with frequency but underestimates the level dependency of the tone-pulse as well as click-evoked latency values. Furthermore, the model correctly predicts the nonlinear wave-V amplitude behavior in response to the chirp stimulation both as a function of chirp sweeping rate and level. Overall, the results support the hypothesis that the pattern of ABR generation is strongly affected by the nonlinear and dispersive processes in the cochlea