Detecting edges in the X-ray surface brightness of galaxy clusters

The effects of many physical processes in the intracluster medium of galaxy clusters imprint themselves in X-ray surface brightness images. It is therefore important to choose optimal methods for extracting information from and enhancing the interpretability of such images. We describe in detail a gradient filtering edge detection method that we previously applied to images of the Centaurus cluster of galaxies. The Gaussian gradient filter measures the gradient in the surface brightness distribution on particular spatial scales. We apply this filter on different scales to Chandra X-ray observatory images of two clusters with active galactic nucleus feedback, the Perseus cluster and M 87, and a merging system, A 3667. By combining filtered images on different scales using radial filters spectacular images of the edges in a cluster are produced. We describe how to assess the significance of features in filtered images. We find the gradient filtering technique to have significant advantages for detecting many kinds of features compared to other analysis techniques, such as unsharp masking. Filtering cluster images in this way in a hard energy band allows shocks to be detected.ACF, HRR and SAW acknowledge support from the ERC Advanced Grant FEEDBACK. The scientific results reported in this article are based on data obtained from the Chandra Data Archive

Can Reduced Intake Associated with Downsizing a High Energy Dense Meal Item be Offset by Increased Vegetable Variety in 3–5-year-old Children?

Large portions of energy dense foods promote overconsumption but offering small portions might lead to compensatory intake of other foods. Offering a variety of vegetables could help promote vegetable intake and offset the effect of reducing the portion size (PS) of a high energy dense (HED) food. Therefore, we tested the effect on intake of reducing the PS of a HED unit lunch item while varying the variety of the accompanying low energy dense (LED) vegetables. In a within-subjects design, 43 3–5-year-old pre-schoolers were served a lunch meal in their nursery on 8 occasions. Children were served a standard (100%) or downsized (60%) portion of a HED sandwich with a side of LED vegetables offered as a single (carrot, cherry tomato, cucumber) or variety (all 3 types) item. Reducing the PS of a HED sandwich reduced sandwich (g) (p < 0.001) and total meal intake (kcal) consumption (p = 0.001) without an increased intake of other foods in the meal (LED vegetables (p = 0.169); dessert (p = 0.835)). Offering a variety of vegetables, compared with a single vegetable, increased vegetable intake (g) (p = 0.003) across PS conditions. Downsizing and variety were effective strategies individually for altering pre-schoolers’ intakes of HED and LED meal items, however, using variety to offset HED downsizing was not supported in the present study

Just Click Here : A Brief Glance at Absurd Electronic Contracts and the Law Failing to Protect Consumers

As e-commerce explodes around the world, consumers’ rights have been left behind. Before the completion of virtually every transaction on the Internet, the onus is placed on consumers to read and agree to an onslaught of terms and conditions. Often hidden in the middle of this extremely lengthy list of terms are massive exemption and limitation of liability clauses that deny consumers most if not all of their rights as “equal” trading partners. The common law principle that all onerous clauses in a contract need to be brought to the attention of the consumer for them to be binding seems to have been lost with the invention of the “click here to agree” button for signing online contracts. As the courts in Canada have not provided clear guidance on this issue thus far, other means must be pursued in order to protect consumers from the near-tyrannical control of unencumbered electronic standard form contracts in e-commerce. This paper will describe the principle of sufficiency of notice as it applies to paper contracts, and then contrast it with the newer jurisprudence that has refused to apply the principle to electronic contracts. The reasons for the refusal will be explored, followed by an examination of why the principle of sufficiency of notice needs to be applied and strengthened to respond to the increasingly onerous provisions hidden in electronic contracts. Finally, some other options for achieving the goal of consumer protection from hidden onerous clauses will be briefly explored. These other options include introducing stiffer consumer protection legislation domestically, the creation of international treaties, developing voluntary standards of contracting, and relying on Internet self-regulation

Subtle changes in the flavour and texture of a drink enhance expectations of satiety

Background: The consumption of liquid calories has been implicated in the development of obesity and weight gain. Energy-containing drinks are often reported to have a weak satiety value: one explanation for this is that because of their fluid texture they are not expected to have much nutritional value. It is important to consider what features of these drinks can be manipulated to enhance their expected satiety value. Two studies investigated the perception of subtle changes in a drink’s viscosity, and the extent to which thick texture and creamy flavour contribute to the generation of satiety expectations. Participants in the first study rated the sensory characteristics of 16 fruit yogurt drinks of increasing viscosity. In study two, a new set of participants evaluated eight versions of the fruit yogurt drink, which varied in thick texture, creamy flavour and energy content, for sensory and hedonic characteristics and satiety expectations. Results: In study one, participants were able to perceive small changes in drink viscosity that were strongly related to the actual viscosity of the drinks. In study two, the thick versions of the drink were expected to be more filling and have a greater expected satiety value, independent of the drink’s actual energy content. A creamy flavour enhanced the extent to which the drink was expected to be filling, but did not affect its expected satiety. Conclusions: These results indicate that subtle manipulations of texture and creamy flavour can increase expectations that a fruit yogurt drink will be filling and suppress hunger, irrespective of the drink’s energy content. A thicker texture enhanced expectations of satiety to a greater extent than a creamier flavour, and may be one way to improve the anticipated satiating value of energy-containing beverages

Efimov effect in quantum magnets

Physics is said to be universal when it emerges regardless of the underlying microscopic details. A prominent example is the Efimov effect, which predicts the emergence of an infinite tower of three-body bound states obeying discrete scale invariance when the particles interact resonantly. Because of its universality and peculiarity, the Efimov effect has been the subject of extensive research in chemical, atomic, nuclear and particle physics for decades. Here we employ an anisotropic Heisenberg model to show that collective excitations in quantum magnets (magnons) also exhibit the Efimov effect. We locate anisotropy-induced two-magnon resonances, compute binding energies of three magnons and find that they fit into the universal scaling law. We propose several approaches to experimentally realize the Efimov effect in quantum magnets, where the emergent Efimov states of magnons can be observed with commonly used spectroscopic measurements. Our study thus opens up new avenues for universal few-body physics in condensed matter systems.Comment: 7 pages, 5 figures; published versio

Body composition impacts appetite regulation in middle childhood. A prospective study of Norwegian community children

Background Research suggests a role for both fat mass and muscle mass in appetite regulation, but the longitudinal relationships between them have not yet been examined in children. The present study therefore aimed to explore the prospective relationships between fat mass, muscle mass and the appetitive traits food responsiveness and satiety responsiveness in middle childhood. Methods Food responsiveness and satiety responsiveness were measured using the parent-reported Children’s Eating Behavior Questionnaire in a representative sample of Norwegian 6 year olds, followed up at 8 and 10 years of age (n = 807). Body composition was measured by bioelectrical impedance. Results Applying a structural equation modeling framework we found that higher fat mass predicted greater increases in food responsiveness over time, whereas greater muscle mass predicted decreases in satiety responsiveness. This pattern was consistent both from ages 6 to 8 and from ages 8 to 10 years. Conclusions Our study is the first to reveal that fat mass and muscle mass predict distinct changes in different appetitive traits over time. Replication of findings in non-European populations are needed, as are studies of children in other age groups. Future studies should also aim to reveal the underlying mechanisms

Does Habitual Physical Activity Increase the Sensitivity of the Appetite Control System? A Systematic Review.

BACKGROUND: It has been proposed that habitual physical activity improves appetite control; however, the evidence has never been systematically reviewed. OBJECTIVE: To examine whether appetite control (e.g. subjective appetite, appetite-related peptides, food intake) differs according to levels of physical activity. DATA SOURCES: Medline, Embase and SPORTDiscus were searched for articles published between 1996 and 2015, using keywords pertaining to physical activity, appetite, food intake and appetite-related peptides. STUDY SELECTION: Articles were included if they involved healthy non-smoking adults (aged 18-64 years) participating in cross-sectional studies examining appetite control in active and inactive individuals; or before and after exercise training in previously inactive individuals. STUDY APPRAISAL AND SYNTHESIS: Of 77 full-text articles assessed, 28 studies (14 cross-sectional; 14 exercise training) met the inclusion criteria. RESULTS: Appetite sensations and absolute energy intake did not differ consistently across studies. Active individuals had a greater ability to compensate for high-energy preloads through reductions in energy intake, in comparison with inactive controls. When physical activity level was graded across cross-sectional studies (low, medium, high, very high), a significant curvilinear effect on energy intake (z-scores) was observed. LIMITATIONS: Methodological issues existed concerning the small number of studies, lack of objective quantification of food intake, and various definitions used to define active and inactive individuals. CONCLUSION: Habitually active individuals showed improved compensation for the energy density of foods, but no consistent differences in appetite or absolute energy intake, in comparison with inactive individuals. This review supports a J-shaped relationship between physical activity level and energy intake. Further studies are required to confirm these findings. PROSPERO REGISTRATION NUMBER: CRD42015019696

Acute post-exercise energy and macronutrient intake in lean and obese youth: a systematic review and meta-analysis

Aim: This review aims to determine if acute exercise affects subsequent energy and macronutrients intake in obese and non-obese children and adolescents. Methods: Databases were searched between January 2015 and December 2015 for studies reporting energy and/or macronutrients intake immediately after an acute exercise and control condition, in children and adolescents. From the initial 118 references found, 14 were included for subsequent analysis after screening representing 31 acute exercise conditions that varied in intensity, duration and modality. Results: One study found increased energy intake after exercise, seven decreased and 23 revealed no change. The meta-analysis revealed a significant effect of acute exercise on intake in obese but not in lean youth by a mean difference of −0.430 (95% confidence interval=−0.703 to −0.157, P=0.002) displaying low heterogeneity (I2=0.000; Q=5.875; df=9, P=0.752). The analysis showed that intense exercise only reduces intake in obese children (no intensity effect in lean). Unchanged macronutrients intake was reported in nine studies as opposed to three which found modified lipids, protein and/or carbohydrate intake. Conclusion: Although acute exercise does not affect energy intake in lean, it appears to reduced food intake in obese youth when intense, without altering the macronutrients composition of the meal

Increasing Foreign Aid for Inclusive Human Development in Africa

In the light of evidence that poverty has been decreasing in all regions of the world with the exception of Africa, where about 45% of countries in sub-Saharan Africa did not achieve the Millennium development goal extreme poverty target, this study assesses whether increasing foreign aid improves inclusive human development. The investigation is on 53 African countries for the period 2005–2012. The empirical analysis is based on (1) the generalised method of moments (GMM) to control for persistence in inclusive human development, simultaneity and time-invariant omitted variables and (2) Instrumental Variable Tobit Regressions to control for simultaneity and the limited range in the dependent variable. The adopted foreign aid variables are: ‘humanitarian assistance’, ‘action on debt’ ‘aid for social infrastructure’, ‘aid to the productive sector’, ‘aid to the multi sector’, ‘aid for economic infrastructure’ and ‘programme assistance’. The following findings are established. From the GMM specifications, there are (1) synergy effects from ‘aid to the productive sector’ and a positive net effect from ‘programme assistance’ and (2) negative net impacts from ‘aid to social infrastructure’ and human assistance, albeit with positive marginal effects. From Instrumental Variable Tobit regressions (1) there is a synergy effect from ‘aid for economic infrastructure’ and (2) there are negative net impacts from ‘aid for social infrastructure’, ‘aid to the productive sector’ and human assistance, albeit with positive marginal effects. Policy implications are discussed