Stellar adiabatic mass loss model and applications

Roche-lobe overflow and common envelope evolution are very important in binary evolution, which is believed to be the main evolutionary channel to hot subdwarf stars. The details of these processes are difficult to model, but adiabatic expansion provides an excellent approximation to the structure of a donor star undergoing dynamical time scale mass transfer. We can use this model to study the responses of stars of various masses and evolutionary stages as potential donor stars, with the urgent goal of obtaining more accurate stability criteria for dynamical mass transfer in binary population synthesis studies. As examples, we describe here several models with the initial masses equal to 1 Msun and 10 Msun, and identify potential limitations to the use of our results for giant-branch stars.Comment: 7 pages, 5 figures,Accepted for publication in AP&SS, Special issue Hot Sub-dwarf Stars, in Han Z., Jeffery S., Podsiadlowski Ph. ed

Ação de reguladores vegetais no crescimento de tomateiro (Lycopersicon esculentum Mill. cv. «Miguel Pereira»)

This research deals with the effects of exogenous growth regulators on development of the tomato cultivar «Miguel Pereira». Observations of tomato plants treated with (2-chloroethyl) trimethylammonium chloride (2,000 ppm) and succinic acid -2,2-d:methyi-hydrazide (3,000 ppm) showed that growth regulators induced little variation in plant height. Gibberellic acid (100 ppm) caused greater variation in height.Estudaram-se em condições de casa de vegetação, os efeitos da aplicação de reguladores vegetais no crescimento do tomateiro cultivar "Miguel Pereira". Além do tratamento controle, aplicou-se, 44 dias após a semeadura, cloreto de (2-cloroetil) trimetilamônio 2.000 ppm, ácido succínico -2,2-dimetilhidrazida 3.000 ppm e ácido giberélico 100 ppm. Observou-se que o GA promoveu maior crescimento, em relação ao controle. O crescimento do tomateiro mostrou-se mais reduzido nas plantas tratadas com CCC e SADH, com relação àquelas pulverizadas com GA e plantas controle

A dense 0.1-solar-mass star in a 51-minute-orbital-period eclipsing binary

Of more than a thousand known cataclysmic variables (CVs), where a white dwarf is accreting from a hydrogen-rich star, only a dozen have orbital periods below 75 minutes1,2,3,4,5,6,7,8,9. One way to achieve these short periods requires the donor star to have undergone substantial nuclear evolution before interacting with the white dwarf10,11,12,13,14, and it is expected that these objects will transition to helium accretion. These transitional CVs have been proposed as progenitors of helium CVs13,14,15,16,17,18. However, no known transitional CV is expected to reach an orbital period short enough to account for most of the helium CV population, leaving the role of this evolutionary pathway unclear. Here we report observations of ZTF J1813+4251, a 51-minute-orbital-period, fully eclipsing binary system consisting of a star with a temperature comparable to that of the Sun but a density 100 times greater owing to its helium-rich composition, accreting onto a white dwarf. Phase-resolved spectra, multi-band light curves and the broadband spectral energy distribution allow us to obtain precise and robust constraints on the masses, radii and temperatures of both components. Evolutionary modelling shows that ZTF J1813+4251 is destined to become a helium CV binary, reaching an orbital period under 20 minutes, rendering ZTF J1813+4251 a previously missing link between helium CV binaries and hydrogen-rich CVs

Research designs considerations for chronic pain prevention clinical trials: IMMPACT recommendations

Although certain risk factors can identify individuals who aremost likely to develop chronic pain, few interventions to prevent chronic pain have been identified. To facilitate the identification of preventive interventions, an IMMPACTmeeting was convened to discuss research design considerations for clinical trials investigating the prevention of chronic pain. We present general design considerations for prevention trials in populations that are at relatively high risk for developing chronic pain. Specific design considerations included subject identification, timing and duration of treatment, outcomes, timing of assessment, and adjusting for risk factors in the analyses.We provide a detailed examination of 4 models of chronic pain prevention (ie, chronic postsurgical pain, postherpetic neuralgia, chronic low back pain, and painful chemotherapy-induced peripheral neuropathy). The issues discussed can, inmany instances, be extrapolated to other chronic pain conditions. These examples were selected because they are representative models of primary and secondary prevention, reflect persistent pain resulting from multiple insults (ie, surgery, viral infection, injury, and toxic or noxious element exposure), and are chronically painful conditions that are treated with a range of interventions. Improvements in the design of chronic pain prevention trials could improve assay sensitivity and thus accelerate the identification of efficacious interventions. Such interventions would have the potential to reduce the prevalence of chronic pain in the population. Additionally, standardization of outcomes in prevention clinical trials will facilitate meta-analyses and systematic reviews and improve detection of preventive strategies emerging from clinical trials

A non-hydrostatic Rhea

Radiometric data obtained during Cassini\u2019s close flyby of Rhea, on 26 November 2005, has been subject to several published analyses aiming to determine the satellite\u2019s mass and quadrupole gravity moments. Combining aspects of two of these analyses we present our best, unbiased estimates of the gravity field parameters and point out how the constraint of hydrostatic equilibrium adopted by previous analysts affects the results. We present solutions based on a broad range of geophysical assumptions, such as the presence of degree 3 and 4 gravity field constrained at different levels. The result is a balanced approach which describes our current knowledge of Rhea\u2019s gravity field. In the case of a gravity field limited to second degree harmonics the most reliable estimates are GM = 153.9398 \ub1 0.0008 km^3/s^2, 10^6 x J2 = 931.0 \ub1 12.0, 10^6 x C22 = 237.2 \ub1 4.5, and 10^ 6 xS22 = 3.8 \ub1 3.8