De Sitter stability and coarse graining.

We present a 4-dimensional back reaction analysis of de Sitter space for a conformally coupled scalar field in the presence of vacuum energy initialized in the Bunch-Davies vacuum. In contrast to the usual semi-classical prescription, as the source term in the Friedmann equations we use expectation values where the unobservable information hidden by the cosmological event horizon has been neglected i.e. coarse grained over. It is shown that in this approach the energy-momentum is precisely thermal with constant temperature despite the dilution from the expansion of space due to a flux of energy radiated from the horizon. This leads to a self-consistent solution for the Hubble rate, which is gradually evolving and at late times deviates significantly from de Sitter. Our results hence imply de Sitter space to be unstable in this prescription. The solution also suggests dynamical vacuum energy: the continuous flux of energy is balanced by the generation of negative vacuum energy, which accumulatively decreases the overall contribution. Finally, we show that our results admit a thermodynamic interpretation which provides a simple alternate derivation of the mechanism. For very long times the solutions coincide with flat space.

Spacetime Curvature and Higgs Stability after Inflation.

We investigate the dynamics of the Higgs field at the end of inflation in the minimal scenario consisting of an inflaton field coupled to the standard model only through the nonminimal gravitational coupling ξ of the Higgs field. Such a coupling is required by renormalization of the standard model in curved space, and in the current scenario also by vacuum stability during high-scale inflation. We find that for ξ≳1, rapidly changing spacetime curvature at the end of inflation leads to significant production of Higgs particles, potentially triggering a transition to a negative-energy Planck scale vacuum state and causing an immediate collapse of the Universe.

Spacetime curvature and the Higgs stability during inflation.

It has been claimed that the electroweak vacuum may be unstable during inflation due to large fluctuations of the order H in the case of a high inflationary scale as suggested by BICEP2. We compute the standard model Higgs effective potential including UV-induced curvature corrections at one-loop level. We find that for a high inflationary scale a large curvature mass is generated due to renormalization group running of nonminimal coupling ξ, which either stabilizes the potential against fluctuations for ξEW≳6×10(-2), or destabilizes it for ξEW≲2×10(-2) when the generated curvature mass is negative. Only in the narrow intermediate region may the effect of the curvature mass be significantly smaller.

Flux and concentration footprint modelling: state of the art.

Since early 1990s, the development of footprint models has been rapid with presently four different approaches being available: (i) analytical models, (ii) Lagrangian stochastic particle dispersion models, (iii) large-eddy simulations, and (iv) closure models. Parameterizations of some of these approaches have been developed, simplifying the original algorithms for use in practical applications. The paper provides a review of the footprint modelling. It also discusses our present understanding of the theoretical background, the most successful modelling approaches, as well as the usage and benefits of the footprint concept as it relates to flux measurements. There has recently been a trend emerging in modelling the behavior of the footprint functions using a less idealized, more realistic description of inhomogeneities, vegetation structure and topography, ultimately for reactive compounds. The estimation of footprints for application in the real world, complete with a multitude of interesting gaseous and particulate substances, remains a complex problem.

Relationship between changes in physical activity and plasma insulin during a 2.5-year follow-up study.

The association between changes in physical activity, body weight, and diet and fasting plasma insulin was analyzed in a 2.5-year follow-up study of 146 men aged 50 to 60 years. Physical activity was assessed by a 7-day physical activity recall interview, diet by a 4-day food record, and plasma insulin radioimmunologically. Total physical activity decreased from (mean +/- SD) 45.1 +/- 10.1 to 39.0 +/- 6.1 metabolic equivalent (MET) hours (METh).d-1 and conditioning physical activity (> 5.0 METs) from 8.0 +/- 11.2 to 2.7 +/- 5.0 METh.d-1, whereas plasma insulin increased from 8.2 +/- 5.8 to 9.2 +/- 6.7 mU.L-1 and body weight from 80.5 +/- 12.0 to 81.6 +/- 11.6 kg during the follow-up period (P < or = .001 for all). The change in conditioning physical activity correlated inversely (r = -.34, P < .001) and change in body weight positively (r = .42,P < .001) with the change in plasma insulin level. With data adjusted for the baseline insulin level, cardiovascular health status, alcohol intake, change in body weight, smoking, age, and follow-up time, the odds ratio for an increase in fasting plasma insulin was 8.9 (95% CI, 2.1 to 37.1; P = .003) for men with the greatest decrease in conditioning physical activity (< -7 METh) compared with men who reported an increase in conditioning physical activity. The same logistic regression model showed an odds ratio of 9.9 (95% CI, 2.1 to 45.4; P = .003) for the increase in plasma insulin for subjects who gained more than 3.3 kg body weight compared with subjects who lost at least 0.6 kg. Men who consumed at least 12 g.d-1 alcohol at both examinations had an odds ratio of 12.8 (95% CI, 1.7 to 94.5; P = .012) compared with nondrinkers. These data suggest that in middle-aged men, a reduction in physical activity increases the risk for increased plasma insulin independently of alcohol intake and changes in body weight.

Binding of folic acid to serum proteins. V. Tritiated folic acid in the liver.

Sephadex G-200 chromatographies of the liver cell sap of rabbits, 1, 3 and 6 days after an injection of 3H-folic acid activity (FAA) into the circulation, were used in an attempt to study the binding of this labelled FAA to liver proteins. The labelled FAA was quickly accumulated in the liver, and in the cell sap it was grouped chromatographically to two maxima, which corresponded to the two maxima of microbiological FAA (L. casei). The maxima were eluated in the chromatography together with cell sap proteins. The possible coupling of FAA to proteins in the liver is discussed.

Pentose phosphate pathway inhibition in blood cells during anticonceptive hormone therapy.

PIP: The transketolase activity (TKA) of the white and red blood cells of oral contraceptive users was studied in an unselected sample population. Compared with healthy controls of corresponding age, the white cell TKA in the oral contraceptive groups was lowered in about 30%. The red cell TKA was lowered in about 15% of the subjects studied. The most pronounced TKA inactivation was observed in the group taking pills that contained mestranol and megestrol acetate. The glucose tolerance tests were normal. Discontinuing the hormones normalized the white cell TKA.^ieng

Serum folic acid activity (L. casei) in Sephadex gel chromatography.

The folic acid activity (FAA) of the protein zone in DEAE Sephadex A-50 chromatography of normal serum showed the following distribution: most (about 40%) was eluted with protein zone IV (alpha-2-macroglobulin), about 33% with protein zones II-III (transferrin), and the balance with zone V (albumin). In healthy human subjects the variations were relatively small. The repeatability of the chromatography in an individual was good.Towards the end of pregnancy the binding of FAA to protein zones II-III increased, while that to zone IV decreased. The return to normal started a few days after delivery. The binding to zones II-III was greatly increased in patients with pernicious anaemia but no neuropathy. It became normal during B(12) therapy. If the patient had neuropathy, his FAA chromatogram was close to normal. During therapy the amount of unbound FAA decreased rapidly. The use of diphenylhydantoin increased the binding of FAA to protein zone I and to zones II-III. In these patients the binding to protein zone IV was slighter than normal.