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We are building a transition edge sensor (TES) X-ray spectrometer for the Linac Coherent Light Source (LCLS-II) at SLAC National Accelerator Laboratory (SLAC) to coincide with new upgrades for this free electron laser facility. This new X-ray spectrometer will have 1000 TES pixels with 0.5 eV energy resolution for soft X-rays below 1 keV. Multiplexing will be done with microwave SQUID resonators and new specialized electronic hardware developed at SLAC. This spectrometer will use a dilution refrigerator to achieve lower operating temperatures than previous TES spectrometers and will be coupled to the liquid jet endstation at LCLS-II. The spectrometer is designed to operate at much higher count rates than previous TES X-ray spectrometers to take advantage of the high repetition rate of the LCLS-II. Science applications will utilize the high photon collection efficiency and throughput, high energy resolution, as well as its ability to simultaneously measure its full calibrated energy range. [ABSTRACT FROM AUTHOR]

The taxon Forficula auricularia L. (Dermaptera: Forficulidae) is a complex of two sibling species that differ in life history (number of clutches per year and imaginal diapause) and that have diverged at the molecular level. The study of a contact zone in the Pyrenean Mountains, using the PCR-RFLP method on two mitochondrial regions (the 16S rRNA and the Cytochrome Oxidase intergenic region), revealed the coexistence of the sibling species at intermediate altitude (1200 m) whereas at lower and higher altitudes only one species was found. An allozyme study, conducted simultaneously and based on four polymorphic loci (PGI1, AAT1, Est-P1 and Est-P2), showed no sign of nuclear introgression. The apparent lack of hybridization in the field is consistent with a postzygotic barrier observed in the laboratory (a nearly complete failure to produce F1 hybrids). This contact zone is probably a sympatric zone between two genetically differentiated species. [ABSTRACT FROM AUTHOR]

Shape optimization of a mechanical structure is an important issue to find the value of critical parameters. This process has a special interest when the shape modification can be carried out in the environment of CAD software, thus creating a new, optimized object in the database of this software. Such an approach has been developed for geometric models embedding canonical surfaces such as planes, cylinders, cones, etc. However, many situations occur where the geometry of the model uses free form surfaces. The description of a new approach to optimize the shape of a mechanical structure is performed through the analysis of the different steps involved in the case study of a hook. It is an example of an object bounded by free form surfaces subjected to various shape constraints and mechanical requirements. The objective is to minimize the mass. The technique developed proceeds in a CAD software environment through an integrated approach. First, a description of a new mechanism employed to create the deformation of a free form surface is conducted. The resulting deformation is connected to design parameters and relies on an analogy between a mechanical model and the description of a free surface based on a B-spline or a NURBS model. The approach developed largely reduces of the number of optimization parameters, thus reducing drastically the computational effort required during the optimization process. Second, a mesh adaption technique is introduced to adapt and preserve the FE mesh during the optimization process with regard to the shape modification of the hook. This adaption technique is connected to the surface deformation mechanism. Then, the sensitivity analysis required for the optimization process is described according to the geometrical and mechanical aspects of the methods developed. A standard discretized continuous gradient technique is used to evaluate the sensitivity of the mechanical stresses associated to the structure with respect to the mesh node positions. Specific developments are presented to calculate the sensitivity of mesh nodes with respect to the design parameters of the optimization problem. Finally, the optimization process is situated with respect to the CAD software environment and the various treatments required are summarized. The results of the shape optimization are high-lighted both on a computational and on a mechanical basis. [ABSTRACT FROM AUTHOR]

Newly developed millennial δ13C larch tree-ring chronology from Siberia allows reconstruction of summer (July) vapor pressure deficit (VPD) changes in a temperature-limited environment. VPD increased recently, but does not yet exceed the maximum values reconstructed during the Medieval Warm Anomaly. The most humid conditions in the Siberian North were recorded in the Early Medieval Period and during the Little Ice Age. Increasing VPD under elevated air temperature affects the hydrology of these sensitive ecosystems by greater evapotranspiration rates. Further VPD increases will significantly affect Siberian forests most likely leading to drought and forest mortality even under additional access of thawed permafrost water. Adaptation strategies are needed for Siberian forest ecosystems to protect them in a warming world. [ABSTRACT FROM AUTHOR]