Child undernutrition in affluent societies: what are we talking about?

In this paper we set out to explore the prevalence of child undernutrition found in community studies in affluent societies, but a preliminary literature review revealed that, in the absence of a gold standard method of diagnosis, the prevalence largely depends on the measure, threshold and the growth reference used, as well as age. We thus go on to explore describe the common clinical ‘syndromes’ of child undernutrition: wasting, stunting and failure to thrive (weight faltering) and how we have used data from two population-based cohort studies, this paper to explore how much these different ‘syndromes’ overlap and the extent to which they reflect true undernutrition. This analysis revealed that when more than one definition is applied to the same children, a majority are below the lower threshold for only one measure. However, those with both weight faltering and low BMI in infancy, go on in later childhood to show growth and body composition patterns suggestive of previous undernutrition. In older children there is even less overlap and most children with either wasting or low fat seem to be simply growing at one extreme of the normal range. We conclude that in affluent societies the diagnosis of undernutrition is only robust when it relies on a combination of both, that is decline in weight or BMI centile and wasting

Multi-Level Issues in International HRM: Mean Differences, Explained Variance, and Moderated Relationships

[Excerpt] While neither denying that differences in HR systems exist, nor that some of the variety of practices is due to real differences across countries, we will attempt to dissect the issue of International HRM using ideas, concepts, and models emerging from multilevel theory and research. We posit that three ideas are critical to this line of research: Mean differences in the use of HR practices across countries, the amount of variance in HR practices that is explained by countries, and the extent to which countries (or specifically culture) moderates the relationships between HR practices and outcomes. Our conclusion is that these differences may not be as large as we think they are, and may in fact be due less to differences in culture and more to differences in institutional contexts

Transverse, Propagating Velocity Perturbations in Solar Coronal Loops

This short review paper gives an overview of recently observed transverse, propagating velocity perturbations in coronal loops. These ubiquitous perturbations are observed to undergo strong damping as they propagate. Using 3D numerical simulations of footpoint-driven transverse waves propagating in a coronal plasma with a cylindrical density structure, in combination with analytical modelling, it is demonstrated that the observed velocity perturbations can be understood in terms of coupling of different wave modes in the inhomogeneous boundaries of the loops. Mode coupling in the inhomogeneous boundary layers of the loops leads to the coupling of the transversal (kink) mode to the azimuthal (Alfven) mode, observed as the decay of the transverse kink oscillations. Both the numerical and analytical results show the spatial profile of the damped wave has a Gaussian shape to begin with, before switching to exponential decay at large heights. In addition, recent analysis of CoMP (Coronal Multi-channel Polarimeter) Doppler shift observations of large, off- limb, trans-equatorial loops shows that Fourier power at the apex appears to be higher in the high-frequency part of the spectrum than expected from theoretical models. This excess high-frequency FFT power could be tentative evidence for the onset of a cascade of the low-to-mid frequency waves into (Alfvenic) turbulence

Toarcian oceanic anoxic event: An assessment of global causes using belemnite C isotope records

Two hypotheses have been proposed to explain simultaneous large negative excursions (up to 7% PeeDee belemnite) in bulk carbonate (delta(13)C(carb)) and organic carbon isotope records (delta(13)C(org)) from black shales marking the Toarcian oceanic anoxic event (T-OAE). The first explanation envisions recycling of dissolved inorganic carbon (DIC) with a light isotopic signature into the photic zone from the lower levels of a salinity-stratified water mass, essentially requiring a regional paleoceanographic driver of the carbon cycle. The second involves the rapid and massive dissociation of methane from gas hydrates that effectively renders the T-OAE a global perturbation of the carbon cycle. We present C isotope records from belemnites (delta(13)C(bel)) sampled from two localities, calibrated with high-resolution ammonite biostratigraphy and Sr isotope stratigraphy, in Yorkshire (England) and Dotternhausen (Germany), that can be used to assess which model best explains the observed changes in carbon isotopes. Our records of the delta(13)C composition of belemnite calcite do not show the large negative C isotope excursions shown by coeval records of delta(13)C in sedimentary organic matter or bulk sedimentary carbonate. It follows that isotopically light carbon cannot have dominated the ocean-atmosphere carbon reservoir during the Toarcian OAE, as would be required were the methane release hypothesis correct. On the basis of an evaluation of available carbon isotope records we discuss a model in which the recycling of DIC from the deeper levels of a stratified water body, and shallowing of anoxic conditions into the photic zone, can explain all isotopic profiles. In particular, the model accounts for the higher C isotope values of belemnites that are characteristic of open ocean, well-mixed conditions, and the lower C isotope values of neritic phytoplankton communities that recorded the degree of density stratification and shallowing of anoxia in the photic zone

Cognitive support for older people from multimedia options

If older users of multimedia displays could select among presentation options, would they choose display combinations that supported their performance? After three short touch-screen tasks which measured the perceptual and cognitive abilities of 50 older adults, they answered questions about a route on an online map that could be accompanied by written and/or spoken text. Half the participants saw animated routes; and they were less accurate answering questions than those who saw static routes but this did not affect people’s multimedia choices which, although diverse, were systematic. Spoken text was more often selected by people who had lower scores on the spatial working memory task, than by the older adults with higher scores. This suggests that older people with cognitive limitations recognise ways in which multimedia information can be supportive

Full gait cycle analysis of lower limb and trunk kinematics and muscle activations during walking in participants with and without ankle instability

This document is the Accepted Manuscript version of the following article: Lynsey Northeast, Charlotte N. Gautrey, Lindsay Bottoms, Gerwyn Hughes, Andrew C. S. Mitchell, and Andrew Greenhalgh, ‘Full gait cycle analysis of lower limb and trunk kinematics and muscle activations during walking in participants with and without ankle instability’, Gait & Posture, Vol. 64: 114-118, July 2018. Under embargo until 7 June 2019. The final, definitive version is available online at doi: https://doi.org/10.1016/j.gaitpost.2018.06.001Background Chronic ankle instability (CAI) has previously been linked to altered lower limb kinematics and muscle activation characteristics during walking, though little research has been performed analysing the full time-series across the stance and swing phases of gait. Research Question The aim of this study was to compare trunk and lower limb kinematics and muscle activity between those with chronic ankle instability and healthy controls. Methods Kinematics and muscle activity were measured in 18 (14 males, 4 females) healthy controls (age 22.4 ± 3.6 years, height 177.8 ± 7.6 cm, mass 70.4 ± 11.9 kg, UK shoe size 8.4 ± 1.6), and 18 (13 males, 5 females) participants with chronic ankle instability (age 22.0 ± 2.7 years, height 176.8 ± 7.9 cm, mass 74.1 ± 9.6 kg, UK shoe size 8.1 ± 1.9) during barefoot walking trials, using a combined Helen Hayes and Oxford foot model. Surface electromyography (sEMG) was recorded for the tibialis anterior and gluteus medius. Full curve statistical parametric mapping was performed using independent and paired-samples T-tests. Results No significant differences were observed in kinematic or sEMG variables between or within groups for the duration of the swing phase of gait. A significantly increased forefoot-tibia inversion was seen in the CAI affected limb when compared to the CAI unaffected limb at 4–16% stance (p = 0.039). No other significant differences were observed. Significance There appears to be no differences in muscle activation and movement between CAI and healthy control groups. However, participants with CAI exhibited increased inversion patterns during the stance phase of gait in their affected limb compared to their unaffected limb. This may predispose those with CAI to episodes of giving way and further ankle sprains.Peer reviewedFinal Accepted Versio

Stability and response of polygenic traits to stabilizing selection and mutation

When polygenic traits are under stabilizing selection, many different combinations of alleles allow close adaptation to the optimum. If alleles have equal effects, all combinations that result in the same deviation from the optimum are equivalent. Furthermore, the genetic variance that is maintained by mutation-selection balance is $2 \mu/S$ per locus, where $\mu$ is the mutation rate and $S$ the strength of stabilizing selection. In reality, alleles vary in their effects, making the fitness landscape asymmetric, and complicating analysis of the equilibria. We show that that the resulting genetic variance depends on the fraction of alleles near fixation, which contribute by $2 \mu/S$, and on the total mutational effects of alleles that are at intermediate frequency. The interplay between stabilizing selection and mutation leads to a sharp transition: alleles with effects smaller than a threshold value of $2\sqrt{\mu / S}$ remain polymorphic, whereas those with larger effects are fixed. The genetic load in equilibrium is less than for traits of equal effects, and the fitness equilibria are more similar. We find that if the optimum is displaced, alleles with effects close to the threshold value sweep first, and their rate of increase is bounded by $\sqrt{\mu S}$. Long term response leads in general to well-adapted traits, unlike the case of equal effects that often end up at a sub-optimal fitness peak. However, the particular peaks to which the populations converge are extremely sensitive to the initial states, and to the speed of the shift of the optimum trait value.Comment: Accepted in Genetic

Spectroscopic Pulsational Frequency Identification and Mode Determination of Gamma Doradus Star HD135825

We present the mode identification of frequencies found in spectroscopic observations of the Gamma Doradus star HD135825. Four frequencies were successfully identified: 1.3150 +/- 0.0003 1/d; 0.2902 +/- 0.0004 1/d; 1.4045 +/- 0.0005 1/d; and 1.8829 +/- 0.0005 1/d. These correspond to (l, m) modes of (1,1), (2,-2), (4,0) and (1,1) respectively. Additional frequencies were found but they were below the signal-to-noise limit of the Fourier spectrum and not suitable for mode identification. The rotational axis inclination and vsini of the star were determined to be 87 degrees (nearly edge-on) and 39.7 km/s (moderate for Gamma Doradus stars) respectively. A simultaneous fit of these four modes to the line profile variations in the data gives a reduced chi square of 12.7. We confirm, based on the frequencies found, that HD135825 is a bona fide Gamma Doradus star.Comment: Accepted to MNRAS 2012 March

Interaction of Stress, Lead Burden, and Age on Cognition in Older Men: The VA Normative Aging Study

BACKGROUND. Low-level exposure to lead and to chronic stress may independently influence cognition. However, the modifying potential of psychosocial stress on the neurotoxicity of lead and their combined relationship to aging-associated decline have not been fully examined. OBJECTIVES. We examined the cross-sectional interaction between stress and lead exposure on Mini-Mental State Examination (MMSE) scores among 811 participants in the Normative Aging Study, a cohort of older U.S. men. METHODS. We used two self-reported measures of stress appraisal-a self-report of stress related to their most severe problem and the Perceived Stress Scale (PSS). Indices of lead exposure were blood lead and bone (tibia and patella) lead. RESULTS. Participants with higher self-reported stress had lower MMSE scores, which were adjusted for age, education, computer experience, English as a first language, smoking, and alcohol intake. In multivariable-adjusted tests for interaction, those with higher PSS scores had a 0.57-point lower (95% confidence interval, -0.90 to 0.24) MMSE score for a 2-fold increase in blood lead than did those with lower PSS scores. In addition, the combination of high PSS scores and high blood lead categories on one or both was associated with a 0.05-0.08 reduction on the MMSE for each year of age compared with those with low PSS score and blood lead level (p < 0.05). CONCLUSIONS. Psychological stress had an independent inverse association with cognition and also modified the relationship between lead exposure and cognitive performance among older men. Furthermore, high stress and lead together modified the association between age and cognition.National Institutes of Health (R01ES07821, R01HL080674, R01HL080674-02S1, R01ES013744, ES05257-06A1, P20MD000501, P42ES05947, ES03918-02); National Center for Research Resources General Clinical Research Center (M01RR02635); Leaves of Grass Foundation; United States Department of Veterans Affair