Once weekly alendronate produces a greater decrease in bone resorption than daily risedronate

peer reviewe

Generalized Extreme Value distribution parameters as dynamical indicators of Stability

We introduce a new dynamical indicator of stability based on the Extreme Value statistics showing that it provides an insight on the local stability properties of dynamical systems. The indicator perform faster than other based on the iteration of the tangent map since it requires only the evolution of the original systems and, in the chaotic regions, gives further information about the information dimension of the attractor. A numerical validation of the method is presented through the analysis of the motions in a Standard map

Effects of stochastic parametrization on extreme value statistics

Extreme geophysical events are of crucial relevance to our daily life: they threaten human lives and cause property damage. To assess the risk and reduce losses, we need to model and probabilistically predict these events. Parametrizations are computational tools used in the Earth system models, which are aimed at reproducing the impact of unresolved scales on resolved scales. The performance of parametrizations has usually been examined on typical events rather than on extreme events. In this paper, we consider a modified version of the two-level Lorenz’96 model and investigate how two parametrizations of the fast degrees of freedom perform in terms of the representation of extreme events. One parametrization is constructed following Wilks [Q. J. R. Meteorol. Soc. 131, 389–407 (2005)] and is constructed through an empirical fitting procedure; the other parametrization is constructed through the statistical mechanical approach proposed by Wouters and Lucarini [J. Stat. Mech. Theory Exp. 2012, P03003 (2012); J. Stat. Phys. 151, 850–860 (2013)]. The two strategies show different advantages and disadvantages. We discover that the agreement between parametrized models and true model is in general worse when looking at extremes rather than at the bulk of the statistics. The results suggest that stochastic parametrizations should be accurately and specifically tested against their performance on extreme events, as usual optimization procedures might neglect them. The provision of accurate parametrizations is a task of paramount importance in many scientific areas and specifically in weather and climate modeling. Parametrizations are needed for representing accurately and efficiently the impact of the scales of motions and of the processes that cannot be explicitly represented by the numerical model. Parametrizations are usually constructed in order to optimize the overall performance of the model, thus aiming at an accurate representation of the bulk of the statistics. Nonetheless, numerical models are key to estimating, anticipating, and predicting extreme events. Here, we analyze critically in a simple yet illustrative example the performance of parametrizations in describing extreme events, and we conclude that good performance on typical conditions cannot be in any way extrapolated for rare conditions, which could, nonetheless, be of great practical relevance

Physical activity attenuates the mid-adolescent peak in insulin resistance but by late adolescence the effect is lost: a longitudinal study with annual measures from 9-16 years (EarlyBird 66)

The final publication is available at Springer via http://dx.doi.org/10.1007/s00125-015-3714-5There is another ORE record for this publication: http://hdl.handle.net/10871/34546AIMS/HYPOTHESIS: The aim of this work was to test whether the mid-adolescent peak in insulin resistance (IR) and trends in other metabolic markers are influenced by long-term exposure to physical activity. METHODS: Physical activity (7 day ActiGraph accelerometry), HOMA-IR and other metabolic markers (glucose, fasting insulin, HbA1c, lipids and BP) were measured annually from age 9 years to 16 years in 300 children (151 boys) from the EarlyBird study in Plymouth, UK. The activity level of each child was characterised, with 95% reliability, by averaging their eight annual physical activity measures. Age-related trends in IR and metabolic health were analysed by multi-level modelling, with physical activity as the exposure measure (categorical and continuous) and body fat percentage (assessed by dual-energy X-ray absorptiometry) and pubertal status (according to age at peak height velocity and Tanner stage) as covariates. RESULTS: The peak in IR at age 12-13 years was 17% lower (p < 0.001) in the more active adolescents independently of body fat percentage and pubertal status. However, this difference diminished progressively over the next 3 years and had disappeared completely by the age of 16 years (e.g. difference was -14% at 14 years, -8% at 15 years and +1% at 16 years; 'physical activity × age(2)' interaction, p < 0.01). Triacylglycerol levels in girls (-9.7%, p = 0.05) and diastolic blood pressure in boys (-1.20 mmHg, p = 0.03) tended to be lower throughout adolescence in the more active group. CONCLUSIONS/INTERPRETATION: Our finding that physical activity attenuates IR during mid-adolescence may be clinically important. It remains to be established whether the temporary attenuation in IR during this period has implications for the development of diabetes in adolescence and for future metabolic health generally.Bright Future TrustKirby Laing FoundationPeninsula FoundationEarlyBird Diabetes TrustNational Institute for Health Research (NIHR) Collaborations for Leadership in Applied Health Research and Care (CLAHRC

An Assessment of Recent and Future Temperature Change over the Sichuan Basin, China, using CMIP5 Climate Models

The Sichuan basin is one of the most densely populated regions of China, making the area particularly vulnerable to the adverse impacts associated with future climate change. As such, climate models are important for understanding regional and local impacts of climate change and variability, like heat stress and drought. In this study, climate models from phase 5 of the Coupled Model Intercomparison Project (CMIP5) are validated over the Sichuan basin by evaluating how well each model can capture the phase, amplitude, and variability of the regionally observed mean, maximum, and minimum temperature between 1979 and 2005. The results reveal that the majority of the models do not capture the basic spatial pattern and observed means, trends, and probability distribution functions. In particular, mean and minimum temperatures are underestimated, especially during the winter, resulting in biases exceeding −3°C. Models that reasonably represent the complex basin topography are found to generally have lower biases overall. The five most skillful climate models with respect to the regional climate of the Sichuan basin are selected to explore twenty-first-century temperature projections for the region. Under the CMIP5 high-emission future climate change scenario, representative concentration pathway 8.5 (RCP8.5), the temperatures are projected to increase by approximately 4°C (with an average warming rate of +0.72°C decade−1), with the greatest warming located over the central plains of the Sichuan basin, by 2100. Moreover, the frequency of extreme months (where mean temperature exceeds 28°C) is shown to increase in the twenty-first century at a faster rate compared to the twentieth century.Funding for this research was provided by the Engineering and Physical Sciences Research Council (EPSRC) as part of the Low Carbon Climate-Responsive Heating and Cooling of Cities (LoHCool) project (EP/N009797/1)

Trends in Antarctic Peninsula surface melting conditions from observations and regional climate modeling

Multidecadal meteorological station records and microwave backscatter time-series from the SeaWinds scatterometer onboard QuikSCAT (QSCAT) were used to calculate temporal and spatial trends in surface melting conditions on the Antarctic Peninsula (AP). Four of six long-term station records showed strongly positive and statistically significant trends in duration of melting conditions, including a 95% increase in the average annual positive degree day sum (PDD) at Faraday/Vernadsky, since 1948. A validated, threshold-based melt detection method was employed to derive detailed melt season onset, extent, and duration climatologies on the AP from enhanced resolution QSCAT data during 1999–2009. Austral summer melt on the AP was linked to regional- and synoptic-scale atmospheric variability by respectively correlating melt season onset and extent with November near-surface air temperatures and the October–January averaged index of the Southern Hemisphere Annular Mode (SAM). The spatial pattern, magnitude, and interannual variability of AP melt from observations was closely reproduced by simulations of the regional model RACMO2. Local discrepancies between observations and model simulations were likely a result of the QSCAT response to, and RACMO2 treatment of, ponded surface water, and the relatively crude representation of coastal climate in the 27 km RACMO2 grid

Evidence for energy conservation during pubertal growth. A 10-year longitudinal study (EarlyBird 71)

BACKGROUND: Diabetes is closely linked to obesity, and obesity rates climb during adolescence for reasons that are not clear. Energy efficiency is important to obesity, and we describe a temporary but substantial fall in absolute energy expenditure, compatible with improved energy efficiency, during the rapid growth phase of puberty. METHODS: In a longitudinal cohort study lasting 10 years, we measured voluntary energy expenditure as physical activity (PA) by accelerometry, involuntary energy expenditure as resting energy expenditure (REE) by oxygen consumption, body mass index (BMI) and body composition by dual energy X-ray absorptiometry annually on 10 occasions from 7 to 16 years in the 347 children of the EarlyBird study. We used mixed effects modelling to analyse the trends in REE and their relationship to BMI, lean mass (LM), fat mass (FM), age, PA and pubertal stage. RESULTS: Relative REE and total PA fell during puberty, as previously described, but the longitudinal data and narrow age-range of the cohort (s.d.±4m) revealed for the first time a substantial fall in absolute REE during the period of maximum growth. The fall became clearer still when adjusted for FM and LM. The fall could not be explained by fasting insulin, adiponectin, leptin, luteinising hormone or follicle stimulating hormone. CONCLUSIONS: There appears to be a temporary but substantial reduction in energy expenditure during puberty, which is unrelated to changes in body composition. If it means higher energy efficiency, the fall in REE could be advantageous in an evolutionary context to delivering the extra energy needed for pubertal growth, but unfavourable to weight gain in a contemporary environment.International Journal of Obesity advance online publication, 4 October 2016; doi:10.1038/ijo.2016.158.We are grateful to the Bright futures trust, Fountain Foundation, BUPA Foundation, EarlyBird Diabetes Trust and countless individual donors who made this study possible

Ogre and Pythia: An Invariance Proof Method for Weak Consistency Models

We design an invariance proof method for concurrent programs parameterised by a weak consistency model. The calculational design of the invariance proof method is by abstract interpretation of a truly parallel analytic semantics. This generalises the methods by Lamport and Owicki-Gries for sequential consistency. We use cat as an example of language to write consistency specifications of both concurrent programs and machine architectures

Reduced oxide soldering activation (ROSA) PWB solderability testing

The effect of ROSA pretreatment on the solderability of environmentally stressed PWB test coupons was investigated. The PWB surface finish was an electroplated, reflowed solder. Test results demonstrated the ability to recover plated-through-hole fill of steam aged samples with solder after ROSA processing. ROSA offers an alternative method for restoring the solderability of aged PWB surfaces

FACTS-international year 2

Summary Objectives:  To compare alendronate 70 mg once weekly (OW) with risedronate 35 mg OW with respect to change in bone mineral density (BMD), biochemical markers and upper gastrointestinal (UGI) tolerability over 24 months. Methods:  This was a 12-month extension to the Fosamax® Actonel® Comparison Trial international study (FACTS). Postmenopausal women with osteoporosis randomly assigned to either alendronate 70 mg OW or risedronate 35 mg OW for the 12-month base study continued taking the same double-blind study medication. Efficacy measurements were BMD at the hip trochanter, lumbar spine, total hip, and femoral neck and levels of four bone turnover markers at 24 months. The primary hypothesis was that alendronate would produce a greater mean per cent increase from baseline in hip trochanter BMD at 24 months. Results:  Trochanter BMD increased significantly from baseline to month 24 in both groups, with a significantly larger increase with alendronate: adjusted mean treatment difference of 1.50% (95% confidence interval: 0.74%, 2.26%; p < 0.001). Similar results were seen at all BMD sites. Significant geometric mean per cent decreases (p < 0.001) from baseline were seen for all four bone turnover markers in both groups, with significantly larger decreases (p < 0.001) with alendronate: adjusted mean treatment differences ranged from 8.9% to 25.3%. No significant differences were seen in incidence of UGI or other adverse events. Conclusions:  Alendronate 70 mg OW yielded significantly greater BMD gains and larger decreases in bone turnover marker levels than risedronate 35 mg OW over 24 months, with no difference in UGI tolerability