Polarographic Determination of Germanium

In the past germanium has been determined by either wet methods or by the spectograph; the spectograph being used for the determination of very small amounts of ger­manium and wet methods used when more than one hundredth of one percent germanium is present. Both of these analyti­cal schemes have weaknesses

Galactic Archaeology with TESS: Prospects for Testing the Star Formation History in the Solar Neighbourhood

A period of quenching between the formation of the thick and thin disks of the Milky Way has been recently proposed to explain the observed age-[{\alpha}/Fe] distribution of stars in the solar neighbourhood. However, robust constraints on stellar ages are currently available for only a limited number of stars. The all-sky survey TESS (Transiting Exoplanet Survey Satellite) will observe the brightest stars in the sky and thus can be used to investigate the age distributions of stars in these components of the Galaxy via asteroseismology, where previously this has been difficult using other techniques. The aim of this preliminary study was to determine whether TESS will be able to provide evidence for quenching periods during the star formation history of the Milky Way. Using a population synthesis code, we produced populations based on various stellar formation history models and limited the analysis to red-giant-branch stars. We investigated the mass-Galactic-disk-height distributions, where stellar mass was used as an age proxy, to test for whether periods of quenching can be observed by TESS. We found that even with the addition of 15% noise to the inferred masses, it will be possible for TESS to find evidence for/against quenching periods suggested in the literature (e.g. between 7 and 9 Gyr ago), therefore providing stringent constraints on the formation and evolution of the Milky Way.Comment: 4 pages, 3 figures, proceedings of "Seismology of the Sun and the Distant Stars 2016", Mario J. P. F. G. Monteiro, Margarida S. Cunha, Joao Miguel T. Ferreira editor

Variational Field Theoretic Approach to Relativistic Scattering

Nonperturbative polaron variational methods are applied, within the so-called particle or worldline representation of relativistic field theory, to study scattering in the context of the scalar Wick - Cutkosky model. Important features of the variational calculation are that it is a controlled approximation scheme valid for arbitrary coupling strengths, the Green functions have all the cuts and poles expected for the exact result at any order in perturbation theory and that the variational parameters are simultaneously sensitive to the infrared as well as the ultraviolet behaviour of the theory. We generalize the previously used quadratic trial action by allowing more freedom for off-shell propagation without a change in the on-shell variational equations and evaluate the scattering amplitude at first order in the variational scheme. Particular attention is paid to the $s$-channel scattering near threshold because here non-perturbative effects can be large. We check the unitarity of a our numerical calculation and find it greatly improved compared to perturbation theory and to the zeroth order variational results.Comment: 26 pages, Latex, 5 postscript figures embedded with epsf, submitted to Nucl. Phys.

First Order Variational Calculation of Form Factor in a Scalar Nucleon--Meson Theory

We investigate a relativistic quantum field theory in the particle representation using a non-perturbative variational technique. The theory is that of two massive scalar particles, `nucleons' and `mesons', interacting via a Yukawa coupling. We calculate the general Euclidean Green function involving two external nucleons and an arbitrary number of external mesons in the quenched approximation for the nucleons. The non-perturbative renormalization and truncation is done in a consistent manner and results in the same variational functional independent of the number of external mesons. We check that the calculation agrees with one-loop perturbation theory for small couplings. As an illustration the special case of meson absorption on the nucleon is considered in detail. We derive the radius of the dressed particle and numerically investigate the vertex function after analytic continuation to Minkowski space.Comment: 28 pages standard LaTeX, 13 uuencoded postscript figures embedded with psfig.st

Knowledge and Perceptions of Non-Nutritive Sweeteners Within the UK Adult Population

Non-nutritive sweeteners (NNS) are popular sugar substitutes that can help in weight and diabetes management, but concerns regarding their use have been raised by the public. This study aimed to investigate knowledge, benefits and safety perceptions of NNS in a sample of UK adults. The impact of knowledge dissemination on the change in perceptions was also examined. An online survey was distributed through social media platforms and UK Universities and was completed by 1589 participants aged 18 years and above. Results showed a high-risk perception of NNS and a lack of knowledge in regulations in nearly half the population sample. The artificial attributes of NNS further limited their acceptance. Risk perception has been significantly linked to a lower con-sumption of sweeteners (p < 0.001) and was affected by gender, occupation, education levels, age and body weight status. Information dissemination significantly reduced risk perception and increased awareness of the benefits of NNS. Results suggest that developing effective communi-cation strategies to educate consumers, potentially through trusted health government agencies and professional bodies, can help them to make informed choices. Education of health profes-sionals could also be valuable in reassuring the public of the benefits of NNS

Summer Conference on ‘Nutrition at Key Stages of the Life Cycle’:Summer conference, Liverpool.

Nutritional requirements of individuals vary across the lifecycle, according to activity,age, and gender. To optimize human health, consideration of nutritional priorities at each stage is needed. This conference brought together multidisciplinary experts in maternal and child nutrition and health, cardiometabolic and plant-based nutrition, and dietitians involved in the care of vulnerable populations, plus nutritional metabolism, health, and ageing. The presentations highlighted the most important nutrition research in these areas, updating knowledge and suggesting how dietary advice and policy could be adapted to incorporate research findings. With the global increase in non-communicable disease (NCD) and nutrition being considered as a key modifiable risk factor for the prevention and management of NCD, this conference was much needed

The Physics of Crystallization from Globular Cluster White Dwarf Stars in NGC 6397

We explore the physics of crystallization in the deep interiors of white dwarf stars using the color-magnitude diagram and luminosity function constructed from proper motion cleaned Hubble Space Telescope photometry of the globular cluster NGC 6397. We demonstrate that the data are consistent with the theory of crystallization of the ions in the interior of white dwarf stars and provide the first empirical evidence that the phase transition is first order: latent heat is released in the process of crystallization as predicted by van Horn (1968). We outline how this data can be used to observationally constrain the value of Gamma = E_{Coulomb}/E_{thermal} near the onset of crystallization, the central carbon/oxygen abundance, and the importance of phase separation.Comment: 5 pages, 5 figures, accepted for publication in the Astrophysical Journal Letter

The Adherence of Singaporean Students in Different Educational Institutions to National Food-Based Dietary Guidelines

There are currently limited data on the dietary habits of young Singaporeans. This study aimed to evaluate the adherence of 17–21 year olds attending different educational institutions using a novel diet-quality scoring method. Dietary data were collected using a single weekday 24 h dietary recall in a cross section of 536 Singaporeans aged 17–21 years. An 11 category scoring system (0.0–100.0) was used to define adherence to food based dietary guidelines. Demographic and self-reported data were also collected via a questionnaire, BMI status, and using Mann-Whitney and Kruskal-Wallis (non-parametric) tests, with post-hoc Bonferroni-corrected tests. The median diet quality score was 48.5 (IQR 40.5, 56.4) for this cohort, with component scores for “Total fruit”, “Whole fruit”, “Total vegetables”, “Dark green leafy & orange vegetables”, “Whole grains”, “Dairy products”, and “Sodium” frequently scoring the minimum value. Median diet quality scores were statistically different for groups by ethnic origin (p < 0.001) and by educational institution (p < 0.001). Intake of fruit, vegetables, and whole grains is minimal, while sodium intake is frequently too high in young Singaporeans. Differences across ethnic groups and types of educational institutions suggest the need for targeted interventions to improve dietary habits in this population

Developing community-based urine sampling methods to deploy biomarker technology for the assessment of dietary exposure

Objective: Obtaining objective, dietary exposure information from individuals is challenging because of the complexity of food consumption patterns and the limitations of self-reporting tools (e.g., FFQ and diet diaries). This hinders research efforts to associate intakes of specific foods or eating patterns with population health outcomes. Design: Dietary exposure can be assessed by the measurement of food-derived chemicals in urine samples. We aimed to develop methodologies for urine collection that minimised impact on the day-to-day activities of participants but also yielded samples that were data-rich in terms of targeted biomarker measurements. Setting: Urine collection methodologies were developed within home settings. Participants: Different cohorts of free-living volunteers. Results: Home collection of urine samples using vacuum transfer technology was deemed highly acceptable by volunteers. Statistical analysis of both metabolome and selected dietary exposure biomarkers in spot urine collected and stored using this method showed that they were compositionally similar to urine collected using a standard method with immediate sample freezing. Even without chemical preservatives, samples can be stored under different temperature regimes without any significant impact on the overall urine composition or concentration of forty-six exemplar dietary exposure biomarkers. Importantly, the samples could be posted directly to analytical facilities, without the need for refrigerated transport and involvement of clinical professionals. Conclusions: This urine sampling methodology appears to be suitable for routine use and may provide a scalable, cost-effective means to collect urine samples and to assess diet in epidemiological studies