1,624 research outputs found
A Thousand Invisible Cords Binding Astronomy and High-Energy Physics
The traditional realm of astronomy is the observation and study of the
largest objects in the Universe, while the traditional domain of high-energy
physics is the study of the smallest things in nature. But these two sciences
concerned with opposite ends of the size spectrum are, in Muir's words, bound
fast by a thousand invisible cords that cannot be broken. In this essay I
propose that collaborations of astronomers and high-energy physicists on common
problems are beneficial for both fields, and that both astronomy and
high-energy physics can advance by this close and still growing relationship.
Dark matter and dark energy are two of the binding cords I will use to
illustrate how collaborations of astronomers and high-energy physicists on
large astronomical projects can be good for astronomy, and how discoveries in
astronomy can guide high-energy physicists in their quest for understanding
nature on the smallest scales. Of course, the fields have some different
intellectual and collaborative traditions, neither of which is ideal. The
cultures of the different fields cannot be judged to be right or wrong; they
either work or they don't. When astronomers and high-energy physicists work
together, the binding cords can either encourage or choke creativity. The
challenge facing the astronomy and high-energy physics communities is to adopt
the best traditions of both fields. It is up to us to choose wisely.Comment: Why "Fundamentalist" Physics Is Good for Astronomy (in response to
the paper of Simon White, arXiv:0704.2291
La marche vers l’Europe des moyens de paiement scripturaux : le projet SEPA.
SEPA, infrastructures de paiement, inter-opérabilité, instruments de paiement, intégration européenne, Eurosystème.
Circadian Timing of Food Intake Contributes to Weight Gain
Studies of body weight regulation have focused almost entirely on caloric intake and energy expenditure. However, a number of recent studies in animals linking energy regulation and the circadian clock at the molecular, physiological, and behavioral levels raise the possibility that the timing of food intake itself may play a significant role in weight gain. The present study focused on the role of the circadian phase of food consumption in weight gain. We provide evidence that nocturnal mice fed a high‐fat diet only during the 12‐h light phase gain significantly more weight than mice fed only during the 12‐h dark phase. A better understanding of the role of the circadian system for weight gain could have important implications for developing new therapeutic strategies for combating the obesity epidemic facing the human population today
The size of the longest filament in the Luminous Red Galaxy distribution
Filaments are one of the most prominent features visible in the galaxy
distribution. Considering the Luminous Red Galaxies (LRGs) in the Sloan Digital
Sky Survey Data Release Seven (SDSS DR7), we have analyzed the filamentarity in
11 nearly two dimensional (2D) sections through a volume limited subsample of
this data. The galaxy distribution, we find, has excess filamentarity in
comparison to a random distribution of points. We use a statistical technique
"Shuffle" to determine , the largest length-scale at which we have
statistically significant filaments. We find that varies in the
range across the 11 slices, with a mean value
. Longer filaments, though possibly
present in our data, are not statistically significant and are the outcome of
chance alignments.Comment: 6 pages, 6 figures, Accepted for publication in MNRA
Dietary beliefs and eating patterns influence metabolic health in type 2 diabetes: A clinic-based study in urban North India
Background: Almost 15% of India\u27s urban adult populace now lives with type 2 diabetes. This study aimed to characterize the eating patterns, knowledge, beliefs, and determinants of food choice, and assess associations with the metabolic health among urban Asian Indians with type 2 diabetes. Materials and Methods: A cross-sectional study of 258 individuals (mean age 55.7 ± 10 years; body mass index 27.1 ± 4.8 kg/m 2 ; diabetes duration 10.1 ± 6.5 years) attending two out-patient clinics in New Delhi, India. Food-related information was collected during a semi-structured interview. Clinical, anthropometric, and biochemical data were recorded. Results: Beliefs related to health and diabetes played a role determining food choice and dietary patterns; erroneous views were associated with the poor food choices and greater metabolic perturbations. Average consumption of fruits/vegetables was low. Intakes were positively associated with intentions to manage diabetes; inversely associated with the waist circumference and negatively correlated with one\u27s degree of personal responsibility for food choice. Household saturated fat usage was common. High fat intakes were positively associated with the taste preference, ratings of perceived "health-value;" waist circumference, glycosylated haemoglobin percentage (HbA1c%) and lipids. Conclusions: Strategies to enhance diabetes control among Asian Indians are required and should encourage fruit/vegetable intake, personal accountability, and consider individual beliefs and preferences. Greater emphasis and resources directed to regular dietary and behavioral counseling may assist.
Effect of a standardized meal on the threshold of exercise-induced myocardial ischemia in patients with stable angina
AbstractObjectives. This study was undertaken to determine the effect of a standardized meal on the ischemie threshold and exercise capacity in a series of 20 patients with stable angina, exerciseinduced ischemia and reversible exercise-induced perfusion defects.Background. It is generally accepted that exercise tolerance in patients with angina is reduced after a meal. However, studies that have addressed this phenomenon have yielded results that are contradictory and inconclusive.Methods. Two exercise tests using the Brace protocol with technetium-99m (99mTc)-sestamibi were performed on consecutive days in a randomized order. One test was performed in the fasting state and the other 30 min after a 1,000-calorle meal.Results. In the postprandial state, exercise time to ischemia was reduced by 20% from 248 ± 93 s to 197 ±87 s (p = 0.0007), time to angina by 15% from 340 ± 82 s to 287 ± 94 s (p = 0.002) and exercise tolerance by 9% from 376 ± 65 s to 344 ± 86 s (p = 0.002). Rate-pressure products at these exercise test end points were not significantly different in the fasting and postprandial tests, and the quantitative 99mTc-sestamibi ischemia score was unchanged.Conclusions. In patients with stable angina, a 1,000-calorie meal significantly reduced tine to ischemia, time to angina and exercise tolerance because of a more rapid increase in myocardial oxygen demand with exercise. The extent and severity of exerciseinduced ischemia were unchanged
Effects of short-term energy restriction on liver lipid content and inflammatory status in severely obese adults: results of a randomised controlled trial (RCT) using two dietary approaches
Short-term very low energy diets (VLED) are used in clinical practice prior to bariatric surgery, however, regimens vary and outcomes for a short intervention are unclear. We examined the effect of two VLEDs; a food-based diet (FD) and meal replacement plan (MRP) (LighterLife) over two weeks in a randomised controlled trial (RCT). We collected clinical and anthropometric data, fasting blood samples, and dietary evaluation questionnaires. Surgeons took liver biopsies and made a visual assessment of the liver. We enrolled 60 participants and 54 completed (FD n=26, MRP n=28). Baseline demographic features, reported energy intake, dietary evaluation and liver histology were comparable between groups. Both diets induced significant weight loss. Perceived difficulty of surgery correlated significantly with the degree of steatosis on histology. Circulating inflammatory mediators: CRP, Fetuin-A and IL6 reduced pre to post diet. Diets achieved comparable weight loss and reduction in inflammatory biomarkers, perceived operative difficulty, and patient evaluation. NAFLD histology assessments post-diet were also not significantly different between diets. Results indicate effectiveness of short term very low energy diets and energy restriction irrespective of macronutrient composition although small sample size precluded detection of subtle differences between interventions
Questions on pure luminosity evolution for ellipticals
The explanation for the existence of an excess population of faint blue
galaxies (FBGs) has been a mystery for nearly two decades, and remains one of
the grand astronomical issues to date. Existing models cannot explain all of
the observational data such as galaxy number counts in the optical and infrared
passbands and the redshift distributions of galaxies. Here, by modelling the
morphological number counts derived from the Hubble Space Telescope, as well as
the number counts in optical and infrared passbands, and the redshift and color
distributions of galaxies obtained from ground-based observations, we show that
the `FBG problem' cannot be resolved if elliptical galaxies are assumed to have
formed in an instantaneous burst of star formation at high redshift with no
subsequent star formation events, which is just the conventional scenario for
formation and evolution of ellipticals. There exist great discrepancies between
the observed color distribution and the predicted distribution for
ellipticals by such a pure luminosity evolution (PLE) model in the context of
the conventional scenario. Neither can the mild evolution (i.e., the star
formation events have lasted for a longer time than those of the instantaneous
burst and passive evolution since the formation of galaxies) for ellipticals be
accepted in the context of PLE assumption. The introduction of dust extinction
also cannot save the PLE models. This conclusion holds for each of the three
cosmological models under consideration: flat, open and -dominated.
Hence, our investigation suggests that PLE assumption for elliptical galaxies
is questionable, and number evolution may be essential for ellipticals.Comment: 20pages (AASTeX), 10 eps figures, 4 tables, to appear in ApJ, 1999,
Vol. 51
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