Timings of Permanent Tooth Emergence in Children of Rural Vanuatu, Melanesia

Introduction Global patterning and timing of permanent tooth emergence is influenced by ethnicity, with no known timings reported for ethnic Melanesian children living in the tropical archipelago of Vanuatu. Aim To determine timings of permanent tooth emergence and sequencing for children who reside in rural Vanuatu. Methods Children aged 4-17 years (n=1026), part of a larger oral health cross-sectional study, were examined recording all permanent teeth present, across four spatially separated islands. Binary logistic modelling established children’s median age of emergence of each permanent tooth for each study area. Results The median emergence of first permanent molars for girls is 4.9-years and 5.3 -years for boys. In all locations, children had all permanent teeth emerge by age 11 years (excluding 3rd molars). Clinically important differences exist for permanent tooth emergence by study area. Discussion Permanent teeth emerge earlier for Ni-Vanuatu children compared to both Melanesian children of Papua New Guinea as well as other ethnicities across Oceanic countries. These results can be used as a set standard for Vanuatu. Early tooth emergence suggests oral health education programmes should target pregnant women with clinical preventive strategies commencing for their children before 5-years of age.

Homing behaviour by destructive crown-of-thorns starfish is triggered by local availability of coral prey

Corallivorous crown-of-thorns starfishes ( Acanthaster spp.) can decimate coral assemblages on Indo-Pacific coral reefs during population outbreaks. While initial drivers of population irruptions leading to outbreaks remain largely unknown, subsequent dispersal of outbreaks appears coincident with depletion of coral prey. Here, we used in situ time-lapse photography to characterize movement of the Pacific crown-of-thorns starfish ( Acanthaster cf. solaris ) in the northern and southern Great Barrier Reef in 2015, during the fourth recorded population outbreak of the starfish, but prior to widespread coral bleaching. Daily tracking of 58 individuals over a total of 1117 h revealed all starfish to move a minimum of 0.52 m, with around half of all tracked starfish showing negligible daily displacement (less than 1 m day −1 ), ranging up to a maximum of 19 m day −1 . Movement was primarily nocturnal and daily displacement varied spatially with variation in local availability of Acropora spp., which is the preferred coral prey. Two distinct behavioural modes emerged: (i) homing movement, whereby tracked paths (as tested against a random-walk-model) involved short displacement distances following distinct ‘outward' movement to Acropora prey (typically displaying ‘feeding scars') and ‘homebound' movement to nearby shelter; versus (ii) roaming movement, whereby individuals showed directional movement beyond initial tracking positions without return. Logistic modelling revealed more than half of all tracked starfish demonstrated homing when local abundance (percentage cover) of preferred Acropora coral prey was greater than 33%. Our results reveal facultative homing by Acanthaster with the prey-dependent behavioural switch to roaming forays providing a mechanism explaining localized aggregations and diffusion of these population irruptions as prey is locally depleted.

Be like and the Constant Rate Effect: from the bottom to the top of the S-curve

The be like quotative emerged rapidly around the English-speaking world and has quickly saturated the quotative systems of young speakers in multiple countries. We study be like (and its covariants) in two communities – Toronto, Canada, and York, United Kingdom – in apparent time and at two separate points in real time. We trace the apparent-time trajectory of be like and its covariants from inception to saturation. We take advantage of the prodigious size of our dataset to examine understudied aspects of the linguistic factors that condition quotative variation. Building on earlier suggestions (Cukor-Avila 2002; Durham et al.2012) that be like might show patterning over time consistent with the Constant Rate Effect (or CRE, Kroch 1989), we argue that the CRE does indeed apply to the rise of be like, but needs to be handled with care. Logistic modelling assumes that the top of the S-curve is located at 100 per cent of a given variable context. In the case of be like, the saturation point is nearer 75–85 per cent, with minor variants retaining small semantic footholds in the system. In conjunction with our analysis, we suggest how to adapt the predictions of the CRE to changes likely to lead to saturation but not categorical use.

Thermotolerance experiments on active and desiccated states of Ramazzottius varieornatus emphasize that tardigrades are sensitive to high temperatures

Global warming is already having harmful effects on habitats worldwide and it is therefore important to gain an understanding of how rising temperatures may affect extant animals. Here, we investigate the tolerance to high temperatures of Ramazzottius varieornatus, a tardigrade frequently found in transient freshwater habitats. Using logistic modelling on activity we evaluate the effect of 24 hour temperature exposures on active tardigrades, with or without a short acclimation period, compared to exposures of desiccated tardigrades. We estimate that the 50% mortality temperature for non-acclimated active tardigrades is 37.1 °C, with a small but significant increase to 37.6 °C following acclimation. Desiccated specimens tolerate much higher temperatures, with an estimated 50% mortality temperature of 82.7 °C following 1 hour exposures, but with a significant decrease to 63.1 °C following 24 hour exposures. Our results show that metabolically active tardigrades are vulnerable to high temperatures, yet acclimatization could provide a tolerance increase. Desiccated specimens show a much higher resilience—exposure-time is, however, a limiting factor giving tardigrades a restricted window of high temperature tolerance. Tardigrades are renowned for their ability to tolerate extreme conditions, but their endurance towards high temperatures clearly has an upper limit—high temperatures thus seem to be their Achilles heel.

Protein intake per day and at each daily meal and skeletal muscle mass declines among older community dwellers in Japan

Objective:To examine associations between protein intake per day and at different meals and skeletal muscle mass declines.Design:Two-year prospective cohort study among older community dwellers.Setting:National Institute for Longevity Sciences–Longitudinal Study of Aging (NILS-LSA) in Japan.Participants:Older men (n 292) and women (n 363) aged 60–87 years who participated in the baseline (2006–2008) and follow-up studies (2008–2010) of NILS-LSA and did not exhibit low skeletal muscle mass at baseline. Muscle mass was assessed using dual-energy X-ray absorptiometry at baseline and follow-up. Low muscle mass was defined as skeletal muscle mass index <7·0 kg/m2 for men and <5·4 kg/m2 for women at follow-up. Daily protein intake and protein intake at each meal were calculated from 3 d dietary records at baseline and sex-stratified tertiles were determined.Results:Mean (sd) protein intake at breakfast, lunch and dinner was 22·7 (7·8), 26·7 (9·3) and 37·4 (10·5) g for men and 19·3 (6·3), 23·2 (7·3) and 28·5 (7·0) g for women, respectively. After adjusting for age, baseline skeletal muscle mass and other confounders in logistic modelling, greater total protein intake was associated with lower prevalence of skeletal muscle mass decline among men at follow-up (P = 0·024). Particularly, the OR (95 % CI) for high lunchtime protein intake was low (0·11 (0·02, 0·61); P = 0·01). No significant association between total protein intake and prevalence of skeletal muscle mass decline was found among women.Conclusions:High total protein intake, particularly at lunchtime, is associated with retention of skeletal muscle mass in men.