Dark Stars: Improved Models and First Pulsation Results

We use the stellar evolution code MESA to study dark stars. Dark stars (DSs), which are powered by dark matter (DM) self-annihilation rather than by nuclear fusion, may be the first stars to form in the Universe. We compute stellar models for accreting DSs with masses up to 10^6 M_{sun}. The heating due to DM annihilation is self-consistently included, assuming extended adiabatic contraction of DM within the minihalos in which DSs form. We find remarkably good overall agreement with previous models, which assumed polytropic interiors. There are some differences in the details, with positive implications for observability. We found that, in the mass range of 10^4 -10^5 M_{sun}, our DSs are hotter by a factor of 1.5 than those in Freese et al.(2010), are smaller in radius by a factor of 0.6, denser by a factor of 3 - 4, and more luminous by a factor of 2. Our models also confirm previous results, according to which supermassive DSs are very well approximated by (n=3)-polytropes. We also perform a first study of dark star pulsations. Our DS models have pulsation modes with timescales ranging from less than a day to more than two years in their rest frames, at z ~ 15, depending on DM particle mass and overtone number. Such pulsations may someday be used to identify bright, cool objects uniquely as DSs; if properly calibrated, they might, in principle, also supply novel standard candles for cosmological studies.Comment: 17 pages; 11 figures; revised version; accepted by Ap

Fast growing tree species in alley cropping systems and their influence on microclimate in Germany

Paper presented at the 13th North American Agroforesty Conference, which was held June 19-21, 2013 in Charlottetown, Prince Edward Island, Canada.In Poppy, L., Kort, J., Schroeder, B., Pollock, T., and Soolanayakanahally, R., eds. Agroforestry: Innovations in Agriculture. Proceedings, 13th North American Agroforestry Conference, Charlottetown, Prince Edward Island, Canada, June 19-21, 2013.The production of energy wood on arable land has been increased in Germany during the last years. In this context, agroforestry systems keep a prominent position in agriculture, since they allow the simultaneous production of energy wood and food or feed on the same field. Fast growing trees arranged in hedge structures (alley cropping) can have positive effects on microclimate. Results of different research studies carried out in several alley cropping sites located in eastern Germany show that wind velocity can be reduced by more than 50 percent, even though tree hedgerows were not higher than four meters. The observed reduction of wind speed was depending on the distance to trees, on the orientation of tree hedges as well as on the width of the crop alleys. Potentially negative effects on crop yield were expected due to the shading the peripheries of crop alleys by trees. However, first results indicate that the reduction of the global radiation by short rotation trees did no show any negative effect on crop yield. As an exception, the crop yield on a post-mining site was evenly higher near trees compared to the center of crop alleys. In summary, the establishment of alley cropping with fast growing trees have positive effects on microclimate and hence on the yield stability of crops cultivated in between the tree hedgerows without any significantly negative impact on the recent practice of land management.Christian B�hm (1), Michael Kanzler (1) and Dirk Freese (1) ; 1. Brandenburg University of Technology, Chair of Soil Protection and Recultivation, Konrad-Wachsmann-Allee 6, D-03046 Cottbus, Germany.Includes bibliographical references

Choir singing improves respiratory muscle strength and quality of life in patients with structural heart disease - HeartChoir: a randomised clinical trial

Most patients with reduced exercise capacity and acquired or congenital structural heart disease also have a reduced respiratory muscle strength. The aim of this pilot study was to investigate whether choir singing in combination with respiratory muscle training positively influences respiratory muscle strength, exercise capacity and quality of life in this population.; In this single-centre, randomised and open-label interventional study we compared respiratory muscle strength, exercise capacity and quality of life in patients with acquired or congenital structural heart disease who received either standard of care and a 12-week intervention (weekly choir rehearsal and daily breathing exercises) or standard of care alone. The primary endpoint was the difference in change in maximum inspiratory pressure (∆MIP%predicted). Secondary endpoints included the difference in change in maximum expiratory pressure (∆MEP%predicted), exercise capacity quantified as maximal oxygen uptake during exercise (∆MVO2%predicted) and quality of life quantified by the Minnesota living with heart failure questionnaire (∆MLHFQ score).; Overall 24 patients (mean age 65, standard deviation [SD] 19 years, 46% male) were randomised after exclusion. ∆MIP%predicted was significantly higher in the intervention group (∆MIP%predicted +14, SD 21% vs −14, SD 23%; p = 0.008) and quality of life improved significantly (∆MLHFQ score −5, SD 6 vs 3, SD 5; p = 0.006) after 12 weeks. ∆MEP%predicted and ∆MVO2%predicted did not differ between both groups (∆MEP%predicted −3, SD 26% vs −3, SD 16%; p = 1.0 and ∆MVO2%predicted 18, SD 12% vs 10, SD 15%; p = 0.2).; Choir singing in combination with respiratory muscle training improved respiratory muscle strength and quality of life in patients with structural heart disease and may therefore be valuable supplements in cardiac rehabilitation. (Clinical trial registration number: NCT03297918)

Агро- и микроклиматическая оценка условий формирования урожайности винограда

Проблема агроклиматического обеспечения аграрного сектора экономики остается важнейшей задачей агрометеорологов и направлена на оценку агроклиматических ресурсов территорий с целью оптимизации размещения сельскохозяйственных культур как условия повышения продуктивности и стабильности отрасли. Актуальность исследований в этом направлении обусловлена отсутствием информации о реально достижимой урожайности отдельных сельскохозяйственных культур как в региональном разрезе, так и на локальном уровне.Проблема агрокліматічеського забезпечення аграрного сектора економіки залишається найважливішою задачею агрометеорології і направлена на оцінку агрокліматічеськіх ресурсів територій з метою оптимізації розміщення сільськогосподарських культур як умови підвищення продуктивності і стабільності галузі. Актуальність досліджень в цьому напрямі обумовлена відсутністю інформації про реально досяжну врожайність окремих сільськогосподарських культур як в регіональному розрізі, так і на локальному рівні

On the Possibility of Large Axion Decay Constants

The decay constant of the QCD axion is required by observation to be small compared to the Planck scale. In theories of "natural inflation," and certain proposed anthropic solutions of the cosmological constant problem, it would be interesting to obtain a large decay constant for axion-like fields from microscopic physics. String theory is the only context in which one can sensibly address this question. Here we survey a number of periodic fields in string theory in a variety of string vacua. In some examples, the decay constant can be parameterically larger than the Planck scale but the effective action then contains appreciable harmonics of order $f_A/M_p$. As a result, these fields are no better inflaton candidates than Planck scale axions.Comment: 17 pages, no figures, minor change mad

Fatal affairs - conjugational transfer of a dinoflagellate-killing plasmid between marine Rhodobacterales

The roseobacter group of marine bacteria is characterized by a mosaic distribution of ecologically important phenotypes. These are often encoded on mobile extrachromosomal replicons. So far, conjugation had only been experimentally proven between the two model organisms Phaeobacter inhibens and Dinoroseobacter shibae. Here, we show that two large natural RepABC-type plasmids from D. shibae can be transferred into representatives of all known major Rhodobacterales lineages. Complete genome sequencing of the newly established Phaeobacter inhibens transconjugants confirmed their genomic integrity. The conjugated plasmids were stably maintained as single copy number replicons in the genuine as well as the new host. Co-cultivation of Phaeobacter inhibens and the transconjugants with the dinoflagellate Prorocentrum minimum demonstrated that Phaeobacter inhibens is a probiotic strain that improves the yield and stability of the dinoflagellate culture. The transconjugant carrying the 191 kb plasmid, but not the 126 kb sister plasmid, killed the dinoflagellate in co-culture

Gauge and Modulus Inflation from 5D Orbifold SUGRA

We study the inflationary scenarios driven by a Wilson line field - the fifth component of a 5D gauge field and corresponding modulus field, within S^1/Z_2 orbifold supergravity (SUGRA). We use our off shell superfield formulation and give a detailed description of the issue of SUSY breaking by the F-component of the radion superfield. By a suitably gauged U(1)R symmetry and including couplings with compensator supermultiplets and a linear multiplet, we achieve a self consistent radion mediated SUSY breaking of no scale type. The inflaton 1-loop effective potential has attractive features needed for successful inflation. An interesting feature of both presented inflationary scenarios are the red tilted spectra with ns~0.96. For gauge inflation we obtain a significant tensor to scalar ratio r~0.1 of the density perturbations, while for the modulus inflation r is strongly suppressed.Comment: 14 pages, 1 figur