Particle abundance in a thermal plasma: quantum kinetics vs. Boltzmann equation

We study the abundance of a particle species in a thermalized plasma by introducing a quantum kinetic description based on the non-equilibrium effective action. A stochastic interpretation of quantum kinetics in terms of a Langevin equation emerges naturally. We consider a particle species that is stable in the vacuum and interacts with \emph{heavier} particles that constitute a thermal bath in equilibrium and define of a fully renormalized single particle distribution function. The distribution function thermalizes on a time scale determined by the \emph{quasiparticle} relaxation rate. The equilibrium distribution function depends on the full spectral density and features off-shell contributions to the particle abundance. A model of a bosonic field $\Phi$ in interaction with two \emph{heavier} bosonic fields is studied. We find substantial departures from the Bose-Einstein result both in the high temperature and the low temperature but high momentum region. In the latter the abundance is exponentially suppressed but larger than the Bose-Einstein result. We obtain the Boltzmann equation in renormalized perturbation theory and highlight the origin of the differences. We argue that the corrections to the abundance of cold dark matter candidates are observationally negligible and that recombination erases any possible spectral distortions of the CMB. However we expect that the enhancement at high temperature may be important for baryogenesis.Comment: 39 pages, 11 figures. Clarifying remarks. To appear in Physical Review

Observations Supporting the Role of Magnetoconvection in Energy Supply to the Quiescent Solar Atmosphere

Identifying the two physical mechanisms behind the production and sustenance of the quiescent solar corona and solar wind poses two of the outstanding problems in solar physics today. We present analysis of spectroscopic observations from the Solar and Heliospheric Observatory that are consistent with a single physical mechanism being responsible for a significant portion of the heat supplied to the lower solar corona and the initial acceleration of the solar wind; the ubiquitous action of magnetoconvection-driven reprocessing and exchange reconnection of the Sun's magnetic field on the supergranular scale. We deduce that while the net magnetic flux on the scale of a supergranule controls the injection rate of mass and energy into the transition region plasma it is the global magnetic topology of the plasma that dictates whether the released ejecta provides thermal input to the quiet solar corona or becomes a tributary that feeds the solar wind.Comment: 34 pages, 13 figures - In press Astrophysical Journal (Jan 1 2007

Saltwater intrusion induces shifts in soil microbial diversity and carbon use efficiency in a coastal grassland ecosystem

Salt accumulation and salinisation of coastal soils is a global issue. Further, climate change is likely to increase the amount of land affected by salinity due to the increasing frequency and severity of coastal flooding and brackish water ingress. The impact of this on the ability of soils to deliver ecosystem services, particularly carbon (C) storage, however, remains unclear. We hypothesized that coastal inundation would negatively affect C storage by lowering plant C inputs and by placing greater osmotic stress on the microbial community leading to a reduced C use efficiency (CUE). Here, we use a coastal grassland ecosystem, which is becoming increasingly subjected to sea and brackish water flooding, to explore the relationship between plant/microbial growth and CUE along a natural salinity gradient. To reflect steady state conditions, we traced the turnover and partitioning of a low (ambient) dose and high (growth stimulation) dose of 14C-labelled glucose into microbial anabolic and catabolic pools, from which microbial CUE was calculated. This was supported by measurements of the diversity of the bacterial community across the salinity gradient using 16S metabarcoding. Our results showed that coastal flooding significantly reduced plant growth (p < 0.005), increased soil C content (p < 0.05) and induced an increase in microbial CUE under low glucose-C conditions (p < 0.05). Conversely, no significant difference in CUE or microbial growth was apparent when a high glucose-C dose was used. Soil bacterial community alpha (α) diversity increased with soil salinity while beta (β) diversity also shifted in response to the higher saline conditions. Our analysis suggests that the largest impact of coastal flooding on soil C cycling was the inability of the plant community to adapt, leading to higher plant residue inputs as well as the decline in soil structure. Conversely, the microbial community had adapted to the increased salinity, resulting in only small changes in the uptake and metabolic partitioning of C

Review of once-monthly oral ibandronate and the use thereof

An advisory board meeting of key opinion leaders was held in 2015 to discuss the clinical data on oral ibandronate in the treatment of postmenopausal osteoporosis.Boniva 150 mg (ibandronate) oral once-monthly is indicated for the treatment of osteoporosis in postmenopausal women, in order to reduce the risk of vertebral fractures.

The Post-Eruptive Evolution of a Coronal Dimming

We discuss the post-eruptive evolution of a "coronal dimming" based on observations of the EUV corona from the Solar and Heliospheric Observatory and the Transition Region and Coronal Explorer. This discussion highlights the roles played by magnetoconvection-driven magnetic reconnection and the global magnetic environment of the plasma in the "filling" and apparent motion of the region following the eruption of a coronal mass ejection (CME). A crucial element in our understanding of the dimming region evolution is developed by monitoring the disappearance and reappearance of bright TRACE "moss" around the active region giving rise to the CME. We interpret the change in the TRACE moss as a proxy of the changing coronal magnetic field topology behind the CME front. We infer that the change in global magnetic topology also results in a shift of energy balance in the process responsible for the production of the moss emission while the coronal magnetic topology evolves from closed, to open and back to closed again because, following the eruption, the moss reforms around the active region in almost exactly its pre-event configuration. As a result of the moss evolution, combining our discussion with recent spectroscopic results of an equatorial coronal hole, we suggest that the interchangeable use of the term "transient coronal hole" to describe a coronal dimming is more than just a simple coincidence.Comment: In Press ApJ [May 2007] - 15 pages, 5 figures, 7 movies that are available upon request [contact author

Finite-dimensional integrable systems associated with Davey-Stewartson I equation

For the Davey-Stewartson I equation, which is an integrable equation in 1+2 dimensions, we have already found its Lax pair in 1+1 dimensional form by nonlinear constraints. This paper deals with the second nonlinearization of this 1+1 dimensional system to get three 1+0 dimensional Hamiltonian systems with a constraint of Neumann type. The full set of involutive conserved integrals is obtained and their functional independence is proved. Therefore, the Hamiltonian systems are completely integrable in Liouville sense. A periodic solution of the Davey-Stewartson I equation is obtained by solving these classical Hamiltonian systems as an example.Comment: 18 pages, LaTe

Finite dimensional integrable Hamiltonian systems associated with DSI equation by Bargmann constraints

The Davey-Stewartson I equation is a typical integrable equation in 2+1 dimensions. Its Lax system being essentially in 1+1 dimensional form has been found through nonlinearization from 2+1 dimensions to 1+1 dimensions. In the present paper, this essentially 1+1 dimensional Lax system is further nonlinearized into 1+0 dimensional Hamiltonian systems by taking the Bargmann constraints. It is shown that the resulting 1+0 dimensional Hamiltonian systems are completely integrable in Liouville sense by finding a full set of integrals of motion and proving their functional independence.Comment: 10 pages, in LaTeX, to be published in J. Phys. Soc. Jpn. 70 (2001

Risky Sex and HIV Acquisition Among HIV Serodiscordant Couples in Zambia, 2002-2012: What Does Alcohol Have To Do With It?

In this paper we evaluate the effects of heavy alcohol consumption on sexual behavior, HIV acquisition, and antiretroviral treatment (ART) initiation in a longitudinal open cohort of 1929 serodiscordant couples in Lusaka, Zambia from&nbsp;2002 to&nbsp;2012. We evaluated factors associated with baseline heavy alcohol consumption and its association with condomless sex with the study partner, sex outside of the partnership, and ART initiation using multivariable logistic regression. We estimated the effect of alcohol consumption on HIV acquisition using multivariable Cox models. Baseline factors significantly associated with women's heavy drinking (drunk weekly or more in 12-months before enrollment) included woman's older age (adjusted prevalence odds ratio [aPOR]&nbsp;=&nbsp;1.04), partner heavy drinking (aPOR&nbsp;=&nbsp;3.93), and being HIV-infected (aPOR&nbsp;=&nbsp;2.03). Heavy drinking among men was associated with less age disparity with partner (aPOR&nbsp;per year disparity&nbsp;=&nbsp;0.97) and partner heavy drinking (aPOR&nbsp;=&nbsp;1.63). Men's being drunk daily (aOR&nbsp;=&nbsp;1.18), women's being drunk less than monthly (aOR&nbsp;=&nbsp;1.39) vs. never drunk and being in a male HIV-negative and female HIV-positive union (aOR&nbsp;=&nbsp;1.45) were associated with condomless sex. Heavy alcohol use was associated with having 1 or more outside sex partners among men (aOR drunk daily&nbsp;=&nbsp;1.91, drunk weekly&nbsp;=&nbsp;1.32, drunk monthly =&nbsp;2.03 vs. never), and women (aOR drunk monthly&nbsp;=&nbsp;2.75 vs. never). Being drunk weekly or more increased men's risk of HIV acquisition (adjusted hazard ratio [aHR]&nbsp;=&nbsp;1.72). Men and women being drunk weekly or more was associated (p&nbsp;&lt;&nbsp;0.1) with women's seroconversion (aHR&nbsp;=&nbsp;1.42 and aHR&nbsp;=&nbsp;3.71 respectively). HIV-positive women who were drunk monthly or more had lower odds of initiating ART (aOR&nbsp;=&nbsp;0.83; 95% CI&nbsp;=&nbsp;0.70-0.99) adjusting for age, months since baseline and previous pregnancies. Individuals in HIV-serodiscordant couples who reported heavy drinking had more outside sex partnerships and condomless sex with their study partner and were more likely to acquire HIV. HIV-positive women had lower odds of initiating ART if they were heavy drinkers

Worrying Leads to Reduced Concreteness of Problem Elaborations: Evidence for the Avoidance Theory of Worry

Both lay concept and scientific theory have embraced the view that nonpathological worry may be helpful for defining and analyzing problems. To evaluate the quality of problem elaborations, concreteness is a key variable. Two studies with nonclinical student samples are presented in which participants elaborated topics associated with different degrees of worry. In Study 1, participants' elaborations were assessed using problem elaboration charts; in Study 2, they were assessed using catastrophizing interviews. When participants' problem elaborations were rated for concreteness, both studies showed an inverse relationship between degree of worry and concreteness: The more participants worried about a given topic the less concrete was the content of their elaboration. The results challenge the view that worry may promote better problem analyses. Instead they conform to the view that worry is a cognitive avoidance response