NLO electroweak contributions to squark pair production at the LHC

We present the tree-level and next-to-leading order (NLO) electroweak (EW) contributions to squark-squark production at the Large Hadron Collider (LHC) within the framework of the Minimal Supersymmetric Standard Model (MSSM).Comment: To appear in the proceedings of 17th International Conference on Supersymmetry and the Unification of Fundamental Interactions (SUSY09), Boston, USA, 5-10 Jun 200

An Optically Controlled Closing and Opening Semiconductor Switch

A concept for a bulk semiconductor switch is presented, where the conductivity is increased and reduced, respectively, through illumination with light of different wavelengths. The increase in conductivity is accomplished by electron ionization from deep centers and generation of bound holes. The reduction of conductivity is obtained by hole ionization from the excited centers and subsequent recombination of free electrons and holes. The transient behavior of electron and hole density in a high power semiconductor (GaAs:Cu) switch is computed by means of a rate equation model. Changes in conductivity by five orders of magnitude can be obtained

Applied tracers for the observation of subsurface stormflow at the hillslope scale

Rainfall-runoff response in temperate humid headwater catchments is mainly controlled by hydrological processes at the hillslope scale. Applied tracer experiments with fluorescent dye and salt tracers are well known tools in groundwater studies at the large scale and vadose zone studies at the plot scale, where they provide a means to characterise subsurface flow. We extend this approach to the hillslope scale to investigate saturated and unsaturated flow paths concertedly at a forested hillslope in the Austrian Alps. Dye staining experiments at the plot scale revealed that cracks and soil pipes function as preferential flow paths in the fine-textured soils of the study area, and these preferential flow structures were active in fast subsurface transport of tracers at the hillslope scale. Breakthrough curves obtained under steady flow conditions could be fitted well to a one-dimensional convection-dispersion model. Under natural rainfall a positive correlation of tracer concentrations to the transient flows was observed. The results of this study demonstrate qualitative and quantitative effects of preferential flow features on subsurface stormflow in a temperate humid headwater catchment. It turns out that, at the hillslope scale, the interactions of structures and processes are intrinsically complex, which implies that attempts to model such a hillslope satisfactorily require detailed investigations of effective structures and parameters at the scale of interest

Particle-in-cell simulations of rf breakdown

Breakdown voltages of a capacitively coupled radio frequency argon discharge at 27 MHz are studied. We use a one-dimensional electrostatic PIC code to investigate the effect of changing the secondary emission properties of the electrodes on the breakdown voltage, particularly at low pd values. Simulation results are compared with the available experimental results and a satisfactory agreement is found.Comment: 12th International Congress on Plasma Physics, 25-29 October 2004, Nice (France

In-situ-Vergleichstest für Sensoren zur Matrixpotentialmessung

Wassergehalt und Matrixpotenzial sind zentrale bodenhydrologische Zustandsvariablen. Zur in-situ Messung dieser Größen im Freiland bietet der Markt eine zunehmende Vielzahl von konkurrierenden Systemen und Technologien an. Zur Messung des Matrixpotentials existiert allerdings bis heute kein Sensorsystem, das mit Zuverlässigkeit und Genauigkeit das Matrixpotential über den gesamten Feuchtebereich messen kann. Zur Prüfung der Messcharakteristik von Bodenfeuchtesensoren hat ein Konsortium von 10 Institutionen im Jahr 2016 über mehrere Monate eine Vergleichsstudie auf einer homogenisierten Testfläche durchgeführt. Die Fläche war ca. 60 m2 groß, natürlichen meteorologischen Bedingungen ausgesetzt und wurde von Vegetation freigehalten. In einem Raster von 0,5 m Weite wurden 15 verschiedene Systeme zur Messung der Bodenfeuchte und 13 verschiedene Systeme zur Messung des Matrixpotenzials in jeweils vierfacher Wiederholung in 0,2 m Tiefe installiert. In diesem Beitrag sollen spezifisch die Ergebnisse der Matrixpotentialmessungen diskutiert werden, deren Technologie auf direkter Druckmessung (Tensiometer T4, T5, T8 der Fa. UMS), Messungen der dielektrischen Eigenschaften (MPS-1, MPS-2 und MPS-6 der Fa. Decagon Devices) bzw. Messungen der Wärmedissipation (pF-Meter, TensioMark der Fa. EcoTech) beruhen. Wir diskutieren die Ergebnisse hinsichtlich der absoluten Lage und Variabilität der Signale, der Reaktionszeiten auf schnelle Feuchteänderungen und auf Temperaturschwankungen. Die Studie zeigte ferner, wie komplex die Probleme einer Vergleichsstudie im Feld generell sind. Trotz großer Sorgfalt bei der Versuchsanlage konnte z.B. die Homogenitätsannahme nur für eine initiale Periode von wenigen Wochen aufrecht gehalten werden. Ein Starkregenereignis mit Infiltrationsüberschuss führte zur Bildung von Bodenkrusten und oberflächlichen Umverteilungsnetzwerken, und damit zu kleinskaliger Heterogenität der oberen Randbedingung. Generell wirft dies Fragen auf in Hinblick auf die Aussagekraft einzelner Sensorenwerte in Freilandstudien

GaAs Photoconductive Closing Switches with High Dark Resistance and Microsecond Conductivity Decay

Silicon-doped n-type gallium arsenide crystals, compensated with diffused copper, were studied with respect to their application as photoconductive, high-power closing switches. The attractive features of GaAs:Cu switches are their high dark resistivity, their efficient activation with Nd:YAG laser radiation, and their microsecond conductivity decay time constant. In the authors\u27 experiment, electric fields are high as 19 kV/cm were switched, and current densities of up to 10 kA/cm2 were conducted through a closely compensated crystal. At field strengths greater than approximately 10 kV/cm, a voltage `lock-on\u27 effect was observed

Hadronic production of bottom-squark pairs with electroweak contributions

We present the complete computation of the tree-level and the next-to-leading order electroweak contributions to bottom-squark pair production at the LHC. The computation is performed within the minimal supersymmetric extension of the Standard Model. We discuss the numerical impact of these contributions in several supersymmetric scenarios.Comment: 33 pages, v2: preprint numbers correcte

Concordance of KRAS/BRAF Mutation Status in Metastatic Colorectal Cancer before and after Anti-EGFR Therapy

Anti-EGFR targeted therapy is a potent strategy in the treatment of metastatic colorectal cancer (mCRC) but activating mutations in the KRAS gene are associated with poor response to this treatment. Therefore, KRAS mutation analysis is employed in the selection of patients for EGFR-targeted therapy and various studies have shown a high concordance between the mutation status in primary CRC and corresponding metastases. However, although development of therapy related resistance occurs also in the context of novel drugs such as tyrosine kinase-inhibitors the effect of the anti-EGFR treatment on the KRAS/BRAF mutation status itself in recurrent mCRC has not yet been clarified. Therefore, we analyzed 21 mCRCs before/after anti-EGFR therapy and found a pre-/posttherapeutic concordance of the KRAS/BRAF mutation status in 20 of the 21 cases examined. In the one discordant case, further analyses revealed that a tumor mosaicism or multiple primary tumors were present, indicating that anti-EGFR therapy has no influence on KRAS/BRAF mutation status in mCRC. Moreover, as the preselection of patients with a KRASwt genotype for anti-EGFR therapy has become a standard procedure, sample sets such ours might be the basis for future studies addressing the identification of potential anti-EGFR therapy induced genetic alterations apart from KRAS/BRAF mutations

Global assessment of manure management policies and practices

In 2014 an assessment of livestock manure policies was performed in 34 countries in Asia, Africa and Latin America, followed by an in-depth assessment of manure management practices in Bangladesh, Viet Nam, Ethiopia, Malawi, Argentina and Costa Rica. The assessments revealed the key barriers for improving integrated manure management and identified six opportunities for actual practice changes to improve manure related policies as well as farm practices with the overall objective of improving food security while mitigating methane emissions at the same tim

Molecular Epidemiology of Anthrax Cases Associated with Recreational Use of Animal Hides and Yarn in the United States

To determine potential links between the clinical isolate to animal products and their geographic origin, we genotyped (MLVA-8, MVLA-15, and canSNP analysis) 80 environmental and 12 clinical isolates and 2 clinical specimens from five cases of anthrax (California in 1976 [n = 1], New York in 2006 [n = 1], Connecticut in 2007 [n = 2], and New Hampshire in 2009[n = 1]) resulting from recreational handling of animal products. For the California case, four clinical isolates were identified as MLVA-8 genotype (GT) 76 and in the canSNP A.Br.Vollum lineage, which is consistent with the Pakistani origin of the yarn. Twenty eight of the California isolates were in the A.Br.Vollum canSNP lineage and one isolate was in the A.Br. 003/004 canSNP sub-group. All 52 isolates and both clinical specimens related to the New York and Connecticut cases were MLVA-8 GT 1. The animal products associated with the NY and CT cases were believed to originate from West Africa, but no isolates from this region are available to be genotyped for comparison. All isolates associated with the New Hampshire case were identical and had a new genotype (GT 149). Isolates from the NY, CT and NH cases diverge from the established canSNP phylogeny near the base of the A.Br.011/009. This report illustrates the power of the current genotyping methods and the dramatically different epidemiological conditions that can lead to infections (i.e., contamination by a single genotype versus widespread contamination of numerous genotypes). These cases illustrate the need to acquire and genotype global isolates so that accurate assignments can be made about isolate origins