University of California, Davis

About: University of California, Davis is a education organization based out in Davis, California, United States. It is known for research contribution in the topics: Population & Gene. The organization has 78770 authors who have published 180033 publications receiving 8064158 citations. The organization is also known as: UC Davis & UCD.

Food Insecurity Is Positively Related to Overweight in Women

Abstract: Although individuals with poor food security might be expected to have reduced food intake, and thus reduced body fat and less likelihood of being overweight, these associations have not been adequately studied. The purpose of the current study was to examine the relationship between food insecurity and overweight as measured by body mass index (BMI) using data from the nationally representative 1994-1996 Continuing Survey of Food Intakes by Individuals (CSFII). Overweight was defined as BMI >27.3 kg/m(2) for women and 27.8 kg/m(2) for men. Food insecurity was related to overweight status for women (n = 4509, P < 0.0001), but not for men (n = 4970, P = 0.44). Excluding the 11 severely insecure women, the prevalence of overweight among women increased as food insecurity increased, from 34% for those who were food secure (n = 3447), to 41% for those who were mildly food insecure (n = 966) and to 52% for those who were moderately food insecure (n = 86). Food insecurity remained a significant predictor of overweight status, after adjustment for potentially confounding demographic and lifestyle variables (P < 0.01). In a logistic regression analysis, mildly insecure women were 30% more likely to be overweight than those who were food secure [odds ratio (OR) 1.3, P = 0.005]. Thus, food insecurity had an unexpected and paradoxical association with overweight status among women with a higher prevalence of overweight among the food insecure, and a resulting potential for increased incidence of obesity-related chronic diseases. Given that the rates of both overweight and food insecurity are on the rise, this research area warrants further investigation.

Do Gasoline Prices Respond Asymmetrically to Crude Oil Price Changes

Abstract: The authors test and confirm that retail gasoline prices respond more quickly to increases than to decreases in crude oil prices. Among the possible sources of this asymmetry are production/inventory adjustment lags and market power of some sellers. By analyzing price transmission at different points in the distribution chain, the authors attempt to shed light on these theories. Spot prices for generic gasoline show asymmetry in responding to crude oil price changes, which may reflect inventory adjustment effects. Asymmetry also appears in the response of retail prices to wholesale price changes, possibly indicating short-run market power among retailers.

The purchasing power parity debate

Abstract: Originally propounded by the 16th-century scholars of the University of Salamanca, the concept of purchasing power parity (PPP) was revived in the interwar period in the context of the debate concerning the appropriate level at which to re-establish international exchange rate parities. Broadly accepted as a long-run equilibrium condition in the post-war period, it first was advocated as a short-run equilibrium by many international economists in the first few years following the breakdown of the Bretton Woods system in the early 1970s and then increasingly came under attack on both theoretical and empirical grounds from the late 1970s to the mid 1990s. Accordingly, over the last three decades, a large literature has built up that examines how much the data deviated from theory, and the fruits of this research have provided a deeper understanding of how well PPP applies in both the short run and the long run. Since the mid 1990s, larger datasets and nonlinear econometric methods, in particular, have improved estimation. As deviations narrowed between real exchange rates and PPP, so did the gap narrow between theory and data, and some degree of confidence in long-run PPP began to emerge again. In this respect, the idea of long-run PPP now enjoys perhaps its strongest support in more than 30 years, a distinct reversion in economic thought.

Disruption of hyaluronan synthase-2 abrogates normal cardiac morphogenesis and hyaluronan-mediated transformation of epithelium to mesenchyme

Abstract: We identified hyaluronan synthase-2 (Has2) as a likely source of hyaluronan (HA) during embryonic development, and we used gene targeting to study its function in vivo. Has2(-/-) embryos lack HA, exhibit severe cardiac and vascular abnormalities, and die during midgestation (E9.5-10). Heart explants from Has2(-/-) embryos lack the characteristic transformation of cardiac endothelial cells into mesenchyme, an essential developmental event that depends on receptor-mediated intracellular signaling. This defect is reproduced by expression of a dominant-negative Ras in wild-type heart explants, and is reversed in Has2(-/-) explants by gene rescue, by administering exogenous HA, or by expressing activated Ras. Conversely, transformation in Has2(-/-) explants mediated by exogenous HA is inhibited by dominant-negative Ras. Collectively, our results demonstrate the importance of HA in mammalian embryogenesis and the pivotal role of Has2 during mammalian development. They also reveal a previously unrecognized pathway for cell migration and invasion that is HA-dependent and involves Ras activation.