Slater-Pauling Rule and Curie-Temperature of Co2_2-based Heusler compounds

A concept is presented serving to guide in the search for new materials with high spin polarization. It is shown that the magnetic moment of half-metallic ferromagnets can be calculated from the generalized Slater-Pauling rule. Further, it was found empirically that the Curie temperature of Co$_2$ based Heusler compounds can be estimated from a seemingly linear dependence on the magnetic moment. As a successful application of these simple rules, it was found that Co$_2$FeSi is, actually, the half-metallic ferromagnet exhibiting the highest magnetic moment and the highest Curie temperature measured for a Heusler compound

T-tubule depolarization-induced SR Ca2+ release is controlled by dihydropyridine receptor- and Ca(2+)-dependent mechanisms in cell homogenates from rabbit skeletal muscle

In vertebrate skeletal muscle, the voltage-dependent mechanism of rapid sarcoplasmic reticulum (SR) Ca2+ release, commonly referred to as excitation-contraction (EC) coupling, is believed to be mediated by physical interaction between the transverse (T)-tubule voltage-sensing dihydropyridine receptor (DHPR) and the SR ryanodine receptor (RyR)/Ca2+ release channel. In this study, differential T-tubule and SR membrane monovalent ion permeabilities were exploited with the use of an ion-replacement protocol to study T-tubule depolarization-induced SR 45Ca2+ release from rabbit skeletal muscle whole-cell homogenates. Specificity of Ca2+ release was ascertained with the use of the DHPR antagonists D888, nifedipine and PN200-110. In the presence of the "slow" complexing Ca2+ buffer EGTA, homogenates exhibited T-tubule depolarization-induced Ca2+ release comprised of an initial rapid phase followed by a slower release phase. During the rapid phase, approximately 20% of the total sequestered Ca2+ (approximately 30 nmol 45Ca2+/mg protein), corresponding to 100% of the caffeine-sensitive Ca2+ pool, was released within 50 ms. Rapid release could be inhibited fourfold by D888. Addition to release media of the "fast" complexing Ca2+ buffer BAPTA, at concentrations > or = 4 mM, nearly abolished rapid Ca2+ release, suggesting that most was Ca2+ dependent. Addition of millimolar concentrations of either Ca2+ or Mg2+ also greatly reduced rapid Ca2+ release. These results show that T-tubule depolarization-induced SR Ca2+ release from rabbit skeletal muscle homogenates is controlled by T-tubule membrane potential- and by Ca(2+)- dependent mechanisms

Efectos del anegamiento en los frutales. una revisión

Excessive rain, a deficient drainage system, and compacted soils are the principal causes of waterlogging, which can generate a reduction in vegetative growth, changes in plant metabolism, low absorption of water and nutrients, low production, and the death of some organs or complete plants. The damage from waterlogging is major with extended stress and in less tolerant plants. Plants are more tolerant with defensive modifications such as alternate routes of respiration, increased production of antioxidants and ethylene, epinasty induction and the closing of stomata, and the formation of new structures such as aerenchyma, hypertrophied lenticels, and adventitious roots. Fruit trees suffer from lack of oxygen due to flooding. However, the lack of oxygen can lead to death of plants; well executed measures can be very useful to attenuate the negative effects of stress.La lluvia excesiva, un mal o inexistente sistema de drenaje, y los suelos compactados son las causas principales del anegamiento que pueden generar reducción del crecimiento vegetal, cambios en el metabolismo de las plantas, menor absorción de agua y nutrientes, menor producción y la muerte completa de la planta iniciada desde sus órganos. La gravedad del anegamiento en las plantas estará determinada por el tiempo de exposición a este estrés y la tolerancia de éstas, siendo un motivo por el que las plantas pueden presentar modificaciones defensivas como vías alternas de respiración, mayor producción de antioxidantes y etileno, inducción de la epinastia y el cierre de estomas, además la formación de nuevas estructuras como el aerénquima, lenticelas hipertrofiadas y raíces adventicias. No obstante, la falta de oxígeno puede llevar a las plantas a la muerte. Existen medidas que siendo bien ejecutadas pueden ser de mucha utilidad para atenuar los efectos negativos de este estrés

Automated Planning for Configuration Changes

This paper describes a prototype implementation of a configuration system which uses automated planning techniques to compute workflows between declarative states. The resulting workflows are executed using the popular combination of ControlTier and Puppet. This al- lows the tool to be used in unattended “autonomic” situ- ations where manual workflow specification is not feasi- ble. It also ensures that critical operational constraints are maintained throughout the execution of the work- flow. We describe the background to the configuration and planning techniques, the architecture of the proto- type, and show how the system deals with several exam- ples of typical reconfiguration problems

Rac1-Regulated Endothelial Radiation Response Stimulates Extravasation and Metastasis That Can Be Blocked by HMG-CoA Reductase Inhibitors

Radiotherapy (RT) plays a key role in cancer treatment. Although the benefit of ionizing radiation (IR) is well established, some findings raise the possibility that irradiation of the primary tumor not only triggers a killing response but also increases the metastatic potential of surviving tumor cells. Here we addressed the question of whether irradiation of normal cells outside of the primary tumor augments metastasis by stimulating the extravasation of circulating tumor cells. We show that IR exposure of human endothelial cells (EC), tumor cells (TC) or both increases TC-EC adhesion in vitro. IR-stimulated TC-EC adhesion was blocked by the HMG-CoA reductase inhibitor lovastatin. Glycyrrhizic acid from liquorice root, which acts as a Sialyl-Lewis X mimetic drug, and the Rac1 inhibitor NSC23766 also reduced TC-EC adhesion. To examine the in vivo relevance of these findings, tumorigenic cells were injected into the tail vein of immunodeficient mice followed by total body irradiation (TBI). The data obtained show that TBI dramatically enhances tumor cell extravasation and lung metastasis. This pro-metastatic radiation effect was blocked by pre-treating mice with lovastatin, glycyrrhizic acid or NSC23766. TBI of mice prior to tumor cell transplantation also stimulated metastasis, which was again blocked by lovastatin. The data point to a pro-metastatic trans-effect of RT, which likely rests on the endothelial radiation response promoting the extravasation of circulating tumor cells. Administration of the widely used lipid-lowering drug lovastatin prior to irradiation counteracts this process, likely by suppressing Rac1-regulated E-selectin expression following irradiation. The data support the concern that radiation exposure might increase the extravasation of circulating tumor cells and recommend co-administration of lipid-lowering drugs to avoid this adverse effect of ionizing radiation

Phosphorus dosing during catalytic n‑butane oxidation in a μ-reactor: a proof of concept

The selective oxidation of n-butane to maleic anhydride over vanadium–phosphorus oxide catalysts is subject to a dynamic change in the catalyst activity. This phenomenon is called phosphorus dynamics and plays a vital role in the prediction of catalytic reaction rates, but to date, no models measured under transport limitation free conditions have been published. This study presents the first investigation of the phosphorus dynamics over extended periods of time (multiple days on stream) under transport limitation free conditions in a μ-fixed-bed reactor. Initially, temperature variation experiments are conducted to investigate whether phosphorus dynamics takes place in a μ-reactor and to determine the onset of phosphorus loss. Then, a setup for dosing of liquid organophosphorous species on the scale of nL min–1 is proposed, and functionality is demonstrated via step test experiments. Results of the temperature variation showed that phosphorus loss occurs in the μ-reactor but starts at temperatures exceeding those of industrial scale reactors by 30–80 K. It was further observed that addition of steam to the feed increases the intensity of the phosphorus dynamics and lowers the onset temperature. Step test results demonstrated the functionality of the dosing setup if a suitable inert material is chosen and the metal surfaces downstream the dosing are treated according to a passivation procedure proposed in this study. The addition of steam appears to be required for appropriate distribution of the dosed organophosphorous species over the catalyst bed

New Limits on an Intermediate Mass Black Hole in Omega Centauri: II. Dynamical Models

We present a detailed dynamical analysis of the projected density and kinematical data available for the globular cluster Omega Cen. We solve the spherical anisotropic Jeans equation to predict the projected profiles of the RMS velocity in each of the three orthogonal coordinate directions (line of sight, proper motion radial, and proper motion tangential). We fit the models to new HST star count and proper motion data near the cluster center presented in Paper I, combined with existing ground-based measurements. We also derive and model the Gauss-Hermite moments of the observed proper motion distributions. The projected density profile is consistent with being flat near the center, with an upper limit gamma=0.07 on the central logarithmic slope. The RMS proper motion profile is also consistent with being flat near the center, and there are no unusually fast-moving stars. The models provide a good fit and yield a 1-sigma upper limit MBH < 1.2E4 solar masses on the mass of a possible intermediate-mass black hole (IMBH). The inferred upper limit corresponds to MBH/Mtot < 0.43%. We combine this with results for other clusters and discuss the implications for globular cluster IMBH demographics. Tighter limits will be needed to rule out or establish whether globular clusters follow the same black hole demographics correlations as galaxies. The arguments put forward by Noyola et al. (2008) to suspect an IMBH in Omega Cen are not confirmed by our study; the IMBH mass they suggested is firmly ruled out.Comment: 28 pages, 11 figures, ApJ in press. v2 includes additions in response to referee comment

Heteronuclear Decoupling by Multiple Rotating Frame Technique

The paper describes the multiple rotating frame technique for designing modulated rf-fields, that perform broadband heteronuclear decoupling in solution NMR spectroscopy. The decoupling is understood by performing a sequence of coordinate transformations, each of which demodulates a component of the Rf-field to a static component, that progressively averages the chemical shift and dipolar interaction. We show that by increasing the number of modulations in the decoupling field, the ratio of dispersion in the chemical shift to the strength of the rf-field is successively reduced in progressive frames. The known decoupling methods like continuous wave decoupling, TPPM etc, are special cases of this method and their performance improves by adding additional modulations in the decoupling field. The technique is also expected to find use in designing decoupling pulse sequences in Solid State NMR spectroscopy and design of various excitation, inversion and mixing sequences.Comment: 18 pages , 5 figure

Fatal attraction: a critique of Carl Schmitt's international political and legal theory

The ongoing Schmitt revival has extended Carl Schmitt's reach over the fields of international legal and political theory. Neo-Schmittians suggest that his international thought provides a new reading of the history of international law and order, which validates the explanatory power of his theoretical premises – the concept of the political, political decisionism, and concrete-order-thinking. Against this background, this article mounts a systematic reappraisal of Schmitt's international thought in a historical perspective. The argument is that his work requires re-contextualization as the intellectual product of an ultra-intense moment in Schmitt's friend/enemy distinction. It inscribed Hitler's ‘spatial revolution’ into a full-scale reinterpretation of Europe's geopolitical history, grounded in land appropriations, which legitimized Nazi Germany's wars of conquest. Consequently, Schmitt's elevation of the early modern nomos as the model for civilized warfare – the ‘golden age’ of international law – against which American legal universalism can be portrayed as degenerated, is conceptually and empirically flawed. Schmitt devised a politically motivated set of theoretical premises to provide a historical counter-narrative against liberal normativism, which generated defective history. The reconstruction of this history reveals the explanatory limits of his theoretical vocabulary – friend/enemy binary, sovereignty-as-exception, nomos/universalism – for past and present analytical purposes. Schmitt's defective analytics and problematic history compromise the standing of his work for purposes of international theory