Determination of effective temperatures and luminosities for rotating stars

Publisher's version/PDFSpectral energy distributions for models of arbitrarily rotating stars are computed using two-dimensional rotating stellar models, NLTE plane-parallel model atmospheres, and a code to integrate the appropriately weighted intensities over the visible surface of the stellar disk. The spectral energy distributions depend on the inclination angle between the observer and the rotation axis of the model. We use these curves to deduce what one would infer the model’s luminosity and effective temperature to be assuming the object was nonrotating

ASP

A small fraction of intermediate-mass main sequence (A and B type) stars have strong, organised magnetic fields. The large majority of such stars, however, show no evidence for magnetic fields, even when observed with very high precision. In this paper we describe a simple model, motivated by qualitatively new observational results, that provides a natural physical explanation for the small fraction of observed magnetic stars

Sustainability of European winter wheat- and maize-based cropping systems: Economic, environmental and social ex-post assessment of conventional and IPM-based systems

In order to ensure higher sustainability of winter wheat and maize production in Europe, cropping systems featuring different levels of Integrated Pest Management (IPM) need to be tested in the field and validated for their sustainability before being adopted by farmers. However, the sustainability evaluation of cropping systems is difficult to perform effectively due to the complex economic, social and environmental dimensions of sustainability. Within the EU research project PURE, nine long-term experiments were conducted in various European regions from 2011 to 2014, comparing two IPM levels against the conventional system (CS) in winter wheat- and maize-based cropping systems. IPM1 encompassed some pesticide use in semi-diverse crop rotations while IPM2 favoured reduced- and non-chemical methods in diverse rotations. The modified DEXiPM (DEXi Pest Management) model for arable cropping systems was used for ex-post assessments to compare the economic, environmental and social sustainability of these systems. The assessments showed that in six out of nine trials the CS was overall unsustainable because of low evaluation of the environmental sustainability that was mainly due to high pesticide use and simplified crop rotations where the choice of crops is primarily market-driven. In contrast, six IPM1 and five IPM2 systems could be classified as sustainable, achieving ‘medium’ or ‘high’ scores for all three sustainability dimensions. Differences in the socio-economic conditions across countries and/or climatic and soil conditions across experimental trials highlighted that IPM is based on general principles that must be adapted to address specific local conditions. Overall, IPM systems included more diverse crop rotations and practices compared to the CS, promoting IPM-based strategies with less pesticide use but also a reduced reliance on pesticides that could partially compensate for any yield reductions by the savings on pesticide and application costs. It is recommended that the results of the study should be disseminated to policy-makers, advisors and farmers and that their implementation should be considered on a regional level. Regional policies to encourage the adoption of more sustainable systems based on IPM principles, as well as better support by more closely involving the regional advisory services for the general implementation of IPM is further recommended. Ex-post analysis with DEXiPM also identified the constraints of the IPM1 and IPM2 systems evaluated as not sustainable. These were related to i) environmental issues for those IPM1 systems that still relied mainly on pesticide use and had less diverse crop rotations, and ii) economic issues for IPM2 systems, mainly due to the choice of less profitable crops in the rotation, as well as to yield penalties caused by the very low pesticide use or replacing pesticides with less effective non-chemical methods. The identification of these constraints is a valuable input to the local and regional discussion on how to adopt IPM and develop more sustainable cropping systems

Why are some A stars magnetic, while most are not?

A small fraction of intermediate-mass main sequence (A and B type) stars have strong, organised magnetic fields. The large majority of such stars, however, show no evidence for magnetic fields, even when observed with very high precision. In this paper we describe a simple model, motivated by qualitatively new observational results, that provides a natural physical explanation for the small fraction of observed magnetic stars

A review of analytical methods for the determination of four new phosphodiesterase type 5 inhibitors in biological samples and pharmaceutical preparations

The introduction of oral phosphodiesterase type 5 inhibitor therapy in 1998 revolutionized the treatment of erectile dysfunction. Erectile dysfunction is the most common sexual problem in men. It often has a profound effect on intimate relationships and quality of life. The analysis of pharmaceuticals is an important part of the drug development process as well as for routine analysis and quality control of commercial formulations. Whereas the determination of sildenafil citrate, vardenafil and tadalafil are well documented by a variety of methods, there are few publications about the determination of udenafil, lodenafil carbonate, mirodenafil and avanafil. The paper presents a brief review of the action mechanism, adverse effects, pharmacokinetics and the most recent analytical methods that can determine drug concentration in biological matrices and pharmaceutical formulations of these four drugs.A introdução da terapia oral com inibidores da fosfodiesterase tipo 5, em 1998, revolucionou o tratamento da disfunção erétil. A disfunção erétil é o problema sexual mais comum em homens. Muitas vezes tem um efeito profundo nas relações íntimas e na qualidade de vida. A análise de produtos farmacêuticos é uma parte importante do processo de desenvolvimento de fármacos, bem como para a análise de rotina e controle de qualidade das formulações comerciais. Enquanto a determinação do citrato de sildenafila, vardenafila e tadalafila está bem documentada por uma variedade de métodos, existem poucas publicações sobre a determinação de udenafila, carbonato de lodenafila, mirodenafila e avanafila. O artigo apresenta uma breve revisão do mecanismo de ação, efeitos adversos, farmacocinética e os mais recentes métodos analíticos, que podem determinar a concentração do fármaco em matrizes biológicas e formulações farmacêuticas destes quatro fármacos

The corrosion of depleted uranium in terrestrial and marine environments

Depleted Uranium alloyed with titanium is used in armour penetrating munitions that have been fired in a number of conflict zones and testing ranges including the UK ranges at Kirkcudbright and Eskmeals. The study presented here evaluates the corrosion of DU alloy cylinders in soil on these two UK ranges and in the adjacent marine environment of the Solway Firth. The estimated mean initial corrosion rates and times for complete corrosion range from 0.13 to 1.9 g cm−2 y−1 and 2.5–48 years respectively depending on the particular physical and geochemical environment. The marine environment at the experimental site was very turbulent. This may have caused the scouring of corrosion products and given rise to a different geochemical environment from that which could be easily duplicated in laboratory experiments. The rate of mass loss was found to vary through time in one soil environment and this is hypothesised to be due to pitting increasing the surface area, followed by a build up of corrosion products inhibiting further corrosion. This indicates that early time measurements of mass loss or corrosion rate may be poor indicators of late time corrosion behaviour, potentially giving rise to incorrect estimates of time to complete corrosion. The DU alloy placed in apparently the same geochemical environment, for the same period of time, can experience very different amounts of corrosion and mass loss, indicating that even small variations in the corrosion environment can have a significant effect. These effects are more significant than other experimental errors and variations in initial surface area

EFFECT OF THE PHOSPHODIESTERASE 5 INHIBITORS SILDENAFIL, TADALAFIL AND VARDENAFIL ON RAT ANOCOCCYGEUS MUSCLE: FUNCTIONAL AND BIOCHEMICAL ASPECTS

1. The anococcygeus muscle is part of the erectile machinery in male rodents. Phosphodiesterase (PDE) 5 inhibitors enhance and prolong the effects of cGMP, which has a key role in penile erection. The aim of the present study was to provide a functional and biochemical comparison of the three PDE5 inhibitors, namely sildenafil, tadalafil and vardenafil, in the rat anococcygeus muscle. 2. Muscle strips were mounted in 4 mL organ baths and isometric force recorded. Levels of cGMP were measured using an enzyme immunoassay kit. Western blots were used to determine PDE5 protein expression. 3. The PDE5 inhibitors concentration-dependently relaxed carbachol-precontracted anococcygeus muscle; however, vardenafil was more potent (pEC(50) =8.11 +/- 0.05) than sildenafil (7.72 +/- 0.06) or tadalafil (7.69 +/- 0.05). Addition of N(G)-nitro-L-arginine methyl ester (100 mu mol/L) or 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (10 mu mol/L) to the organ baths caused significant rightward shifts in concentration-response curves for all PDE5 inhibitors. 4. Sildenafil, tadalafil and vardenafil (all at 0.1 mu mol/L) caused leftward shifts in the glyceryl trinitrate (GTN) concentration-response curves (by 4.0-, 3.7- and 5.5-fold, respectively). In addition, all three PDE5 inhibitors significantly potentiated relaxation responses to both GTN (0.01-10 mu mol/L) and electrical field stimulation (EFS; 1-32 Hz), with vardenafil having more pronounced effects. 5. All three PDE5 inhibitors reduced EFS-evoked contractions in a concentration-dependent manner over the concentration range 0.001-1 mu mol/L. There were no significant differences between the effects of the three PDE5 inhibitors. 6. Vardenafil (0.01-0.1 mu mol/L) was more potent in preventing cGMP degradation in vitro than sildenafil (0.01-0.1 mu mol/L) and tadalafil (0.01-0.1 mu mol/L). 7. Under control conditions, the expression of PDE5 was higher in the anococcygeus muscle than in the corpus cavernosum. 8. In conclusion, PDE5 inhibitors enhance exogenous and endogenous nitric oxide-mediated relaxation in the rat anococcygeus muscle. The potency of vardenafil was greater than that of either sildenafil or tadalafil.36435836