3,085 research outputs found
Can nutritional label use influence body weight outcomes?
Nutritional labeling has been of much interest to policy makers and health advocates due to rising obesity trends. So can nutritional label use really help reduce body weight outcomes? This study evaluates the impact of nutritional label use on body weight using the propensity score matching technique. We conducted a series of tests related to variable choice of the propensity score specification, quality of matching indicators, robustness checks, and sensitivity to unobserved heterogeneity using Rosenbaum bounds to validate our propensity score exercise. Our results generally suggest that nutritional label use does not affect body mass index. Implications of our findings are discussed.Nutritional Labels, Body Mass Index, Propensity Score Matching, sensitivity analysis
Food involvement and food purchasing behaviour
This paper investigates the factors affecting product class involvement for food. Factors affecting specific aspects of involvement are also explored. The aim is to determine the factors that affect involvement with food and sketch the profile of consumers more likely to be involved or not involved with food. Building on the literature a conceptual model is developed and empirically tested using survey data collected from supermarkets in Athens. Data were analyzed using probit and ordered probit analysis and marginal effects were calculated which show how much the level of involvement or importance is affected when a variable is changed. Results show that younger consumers, those with higher education and income that engage in nutritional label use behaviour and do not prepare food for their household are more likely to have low involvement with food. Less distinctive characteristics are apparent for the highly involved consumers. Different consumer profiles are also associated with different aspects of food involvement based on importance attached to price, ease of preparation, nutrition, taste, and brand name.product class involvement, food involvement, consumer behaviour, food shopping, attribute importance, Consumer/Household Economics, Food Consumption/Nutrition/Food Safety,
Heteroskedasticity, the single crossing property and ordered response models
Heteroskedasticity in ordered response models has not garnered enough attention in the literature. Econometric software packages do not handle this problem satisfactorily either. We provide formulas to calculate heteroskedasticity corrected marginal effects and discrete changes using an approach that deals with single crossing property, a very restrictive assumption of ordered response models.
Body Weight Outcomes and Food Expenditures Among Older Europeans: A simultaneous equation approach
We analyze the inter-relationships between body weight outcomes and food expenditures among older Europeans using a simultaneous equation model. Several statistical tests were conducted to assess endogeneity of selected variables, the exogeneity, relevance, and validity of instruments used, and the identification of the model. Our results generally suggest, contrary to normative views, that food-away-from-home expenditure is negatively related to body mass index (BMI). BMI is negatively related to the percentage of food spent away from home.Body Mass Index, food expenditures, simultaneous equations, Agricultural and Food Policy,
Configuration of influenza hemagglutinin fusion peptide monomers and oligomers in membranes
AbstractThe 20 N-terminal residues of the HA2 subunit of influenza hemagglutinin (HA), known as the fusion peptide, play a crucial role in membrane fusion. Molecular dynamics simulations with implicit solvation are employed here to study the structure and orientation of the fusion peptide in membranes. As a monomer the α-helical peptide adopts a shallow, slightly tilted orientation along the lipid tail–head group interface. The average angle of the peptide with respect to membrane plane is 12.4 °. We find that the kinked structure proposed on the basis of NMR data is not stable in our model because of the high energy cost related to the membrane insertion of polar groups. Because hemagglutinin-mediated membrane fusion is promoted by low pH, we examined the effect of protonation of the Glu and Asp residues. The configurations of the protonated peptides were slightly deeper in the membrane but at similar angles. Finally, because HA is a trimer, we modeled helical fusion peptide trimers. We find that oligomerization affects the insertion depth of the peptide and its orientation with respect to the membrane: a trimer exhibits equally favorable configurations in which some or all of the helices in the bundle insert obliquely deep into the membrane
When a risky prospect is valued more than its best possible outcome
In this paper, we document a violation of normative and descriptive models of decision making under risk. In contrast to uncertainty effects found by Gneezy, List and Wu (2006), some subjects in our experiments valued certain lotteries more than the best possible outcome. We show that the likelihood of observing this effect is positively related to the probability of winning the lottery and negatively related to the value of the maximum outcome. We also demonstrate that this effect can be partially attributed to subjects’ competitiveness and level of comprehension of the lottery mechanism; the competitiveness effects far outweighing comprehension effects.lottery, risk, competitiveness, Vickrey auctions
Retro-oesophageal right subclavian artery in association with thyroid ima artery: a case report, clinical impact and review of the literature
A 37-year-old female Caucasian cadaver with an aberrant right subclavian artery extending from the left side of the aortic arch and following a retro-oesophageal course is presented. A non-recurrent right laryngeal nerve and a thyroid ima artery arising from the lower part of the middle third of the right common carotid artery coexisted. The brachiocephalic trunk was absent, while both common carotid arteries and left subclavian artery followed their normal course. The aim of the current study is to highlight the clinical impact of the above abnormalities providing useful and practically applicable knowledge to interventional clinicians, thoracic and neck surgeons, since the vast majority of documented cases with an arteria lusoria are clinically silent and in most cases discovered incidentally. Clinical manifestations such as dysphagia, chronic cough, and acute ischaemia to the right upper limb may occur, leading to misinterpretation in radiographic examination and complications during neck and thoracic surgery. Review of the literature was also performed and the embryological background of the aberration is highlighted
Improving statistical power of glaucoma clinical trials using an ensemble of cyclical generative adversarial networks
Albeit spectral-domain OCT (SDOCT) is now in clinical use for glaucoma management, published clinical trials relied on time-domain OCT (TDOCT) which is characterized by low signal-to-noise ratio, leading to low statistical power. For this reason, such trials require large numbers of patients observed over long intervals and become more costly. We propose a probabilistic ensemble model and a cycle-consistent perceptual loss for improving the statistical power of trials utilizing TDOCT. TDOCT are converted to synthesized SDOCT and segmented via Bayesian fusion of an ensemble of GANs. The final retinal nerve fibre layer segmentation is obtained automatically on an averaged synthesized image using label fusion. We benchmark different networks using i) GAN, ii) Wasserstein GAN (WGAN) (iii) GAN + perceptual loss and iv) WGAN + perceptual loss. For training and validation, an independent dataset is used, while testing is performed on the UK Glaucoma Treatment Study (UKGTS), i.e. a TDOCT-based trial. We quantify the statistical power of the measurements obtained with our method, as compared with those derived from the original TDOCT. The results provide new insights into the UKGTS, showing a significantly better separation between treatment arms, while improving the statistical power of TDOCT on par with visual field measurements
An atypical biceps brachii and coracobrachialis muscles associated with multiple neurovascular aberrations: a case report with clinical significance
Neural and vascular variations in the axilla and upper limb area are usually paired, but coexistence of muscular aberration on top of this is uncommon. The current case report emphasizes on the unilateral coexistence of a three-headed (tricipital) biceps brachii muscle, a two-headed coracobrachialis with an accessory muscle bundle joining the superficial and deep heads of coracobrachialis muscle. On the ipsilateral side of the 72-year-old male cadaver, a connecting branch originated from the musculocutaneous nerve and joined the median nerve after surpassing the accessory muscle bundle. A large diameter subscapular trunk originated from the 2nd part of the axillary artery and after giving off the 1st lateral thoracic artery trifurcated into a common stem which gave off the 2nd and 3rd lateral thoracic arteries, the circumflex scapular artery and a common branch that gave off the 4th and 5th lateral thoracic arteries and the thoracodorsal artery, as the ultimate branch. All lateral thoracic arteries were accompanied by multiple intercostobra- chial nerves. Documentation of such muscular and neurovascular variants and their embryologic origin increases awareness of their potential impact on diagnosis and treatment of upper limb pathology. To the best of our knowledge, the currently reported cadaveric observations seem to constitute a unique finding.
Ancient human genomes suggest three ancestral populations for present-day Europeans
We sequenced the genomes of a 7,000-year-old farmer from Germany and eight 8,000-year-old hunter-gatherers from Luxembourg and Sweden. We analysed these and other ancient genomes¹-₄ with 2,345 contemporary humans to show that most present-day Europeans derive from at least three highly differentiated populations:west European hunter-gatherers, who contributed ancestry to all Europeans but not to Near Easterners; ancient north Eurasians related to Upper Palaeolithic Siberians³, who contributed to both Europeans and Near Easterners; and early European farmers, who were mainly of Near Eastern origin but also harboured west European hunter-gatherer related ancestry.We model these populations’ deep relationships and show that early European farmers had 44% ancestry from a ‘basal Eurasian’ population that split before the diversification of other non-African lineage
- …