X ray facility for the characterization of the Athena mirror modules at the ALBA synchrotron

The ALBA synchrotron1 Barcelona, Spain is building MINERVA a new X ray beamline designed to support the development of the ATHENA mission Advanced Telescope for High Energy Astrophysics . The beamline design is originally based on the monochromatic pencil beam XPBF 2.02 at the Physikalisch Technische Bundesanstalt PTB , at BESSY II. MINERVA will provide metrology capabilities to integrate stacks produced by cosine company into a mirror module MM and characterize them. It will provide photons with a fixed energy of 1.0 keV with a residual divergence below 1 1 arcsec 2 rms. The beam dimensions at the mirror module is adjustable from 10 10 amp; 956;m2 up to 8 8 mm 2. Interoperability between MINERVA and XPBF 2.0 will be preserved in order to reinforce and boost the production and characterization of the mirror modules. MINERVA is funded by the European Space Agency ESA and the Spanish Ministry of Science and Innovation. Still in the detailed design phase, MINERVA will take 2 years to be completed for operation in 202

Acute carbon dioxide avoidance in Caenorhabditis elegans

Carbon dioxide is produced as a by-product of cellular respiration by all aerobic organisms and thus serves for many animals as an important indicator of food, mates, and predators. However, whether free-living terrestrial nematodes such as Caenorhabditis elegans respond to CO2 was unclear. We have demonstrated that adult C. elegans display an acute avoidance response upon exposure to CO2 that is characterized by the cessation of forward movement and the rapid initiation of backward movement. This response is mediated by a cGMP signaling pathway that includes the cGMP-gated heteromeric channel TAX-2/TAX-4. CO2 avoidance is modulated by multiple signaling molecules, including the neuropeptide Y receptor NPR-1 and the calcineurin subunits TAX-6 and CNB-1. Nutritional status also modulates CO2 responsiveness via the insulin and TGFβ signaling pathways. CO2 response is mediated by a neural circuit that includes the BAG neurons, a pair of sensory neurons of previously unknown function. TAX-2/TAX-4 function in the BAG neurons to mediate acute CO2 avoidance. Our results demonstrate that C. elegans senses and responds to CO2 using multiple signaling pathways and a neural network that includes the BAG neurons and that this response is modulated by the physiological state of the worm

Outcrossing and the Maintenance of Males within C. elegans Populations

Caenorhabditis elegans is an androdioecious nematode with both hermaphrodites and males. Although males can potentially play an important role in avoiding inbreeding and facilitating adaptation, their existence is evolutionarily problematic because they do not directly generate offspring in the way that hermaphrodites do. This review explores how genetic, population genomic, and experimental evolution approaches are being used to address the role of males and outcrossing within C. elegans. Although theory suggests that inbreeding depression and male mating ability should be the primary determinants of male frequency, this has yet to be convincingly confirmed experimentally. Genomic analysis of natural populations finds that outcrossing occurs at low, but not negligible levels, and that observed patterns of linkage disequilibrium consistent with strong selfing may instead be generated by natural selection against outcrossed progeny. Recent experimental evolution studies suggest that males can be maintained at fairly high levels if populations are initiated with sufficient genetic variation and/or subjected to strong natural selection via a change in the environment. For example, as reported here, populations adapting to novel laboratory rearing and temperature regimes maintain males at frequencies from 5% to 40%. Laboratory and field results still await full reconciliation, which may be facilitated by identifying the loci underlying among-strain differences in mating system dynamics

Status of the silicon pore optics technology

Silicon Pore Optics (SPO) uses commercially available monocrystalline double-sided super-polished silicon wafers as a basis to produce mirrors that form lightweight and stiff high-resolution x-ray optics. The technology has been invented by cosine and the European Space Agency (ESA) and developed together with scientific and industrial partners to mass production levels. SPO is an enabling element for large space-based x-ray telescopes such as Athena and ARCUS, operating in the 0.2 to 12 keV band, with angular resolution requirements up to 5 arc seconds. SPO has also shown to be a versatile technology that can be further developed for gamma-ray optics, medical applications and for material research. This paper will summarise the status of the technology and of the mass production capabilities, show latest performance results and discuss the next steps in the development