Calibration and alignment of metrology system for the Nuclear Spectroscopic Telescope Array mission

A metrology system to measure the on-orbit movement of a ten meter mast has been built for the Nuclear Spectroscopic Telescope Array (NuSTAR) x-ray observatory. In this paper, the metrology system is described, and the performance is measured. The laser beam stability is discussed in detail. Pre-launch alignment and calibration are also described. The invisible infrared laser beams must be aligned to their corresponding detectors without deploying the telescope in Earth’s gravity. Finally, a possible method for in-flight calibration of the metrology system is described

An Introduction to the Ecology of Shrines in Spain

http://deepblue.lib.umich.edu/bitstream/2027.42/50836/1/54.pd

Secular and Religious Responses to a Child's Potentially Fatal Illness in the Canary Islands

In the summer of 1985 two-year-old Lucia, the only child of my friends on the island of Tenerife, Lourdes and Eligio, went cross-eyed. After she was given corrective glasses, and then had an operation, she began to have dizzy spells and be unsteady on her feet. Finally in February, 1986, after a bad fall and vomiting, she was taken to a hospital, where a large tumor was found in her brain. She was immediately operated on, and a valve was installed to relieve the pressure on the brain, pending the more complex removal of the tumor. The doctors were pessimistic. They said the chances were 95% that the tumor was malignant; that Lucia might not survive its removal, and that if she did her life would probably be short and unpleasant.

Toribia del Val y el misterioso caminante de Casas de Benítez

The vision of a woman in her garden during a drought in a village in the Spanish province of Cuenca in 1931 suggests the vitality of old stories and the survival at the eve of the Spanish Civil War of the idea of a mysterious stranger or pilgrim, an old way of introducing heaven’s solutions to group problems.La visión experimentada en 1931 por una mujer en su huerto de un pueblo de Cuenca durante una sequía demuestra la pervivencia, en vísperas de la Guerra Civil española, de la idea de un forastero o peregrino misterioso que aparece con instrucciones para el pueblo, una antigua manera de proponer soluciones celestiales a problemas colectivos

The Glove-like Structure of the Conserved Membrane Protein TatC Provides Insight into Signal Sequence Recognition in Twin-Arginine Translocation

In bacteria, two signal-sequence-dependent secretion pathways translocate proteins across the cytoplasmic membrane. Although the mechanism of the ubiquitous general secretory pathway is becoming well understood, that of the twin-arginine translocation pathway, responsible for translocation of folded proteins across the bilayer, is more mysterious. TatC, the largest and most conserved of three integral membrane components, provides the initial binding site of the signal sequence prior to pore assembly. Here, we present two crystal structures of TatC from the thermophilic bacteria Aquifex aeolicus at 4.0 Å and 6.8 Å resolution. The membrane architecture of TatC includes a glove-shaped structure with a lipid-exposed pocket predicted by molecular dynamics to distort the membrane. Correlating the biochemical literature to these results suggests that the signal sequence binds in this pocket, leading to structural changes that facilitate higher order assemblies

Decline of Spectacled Eiders Nesting in Western Alaska

Spectacled eider (Somateria fischeri) populations in western Alaska are now less than 4% of the numbers estimated in the early 1970s. In 1992, an estimated 1721 nesting pairs remained on the Yukon-Kuskokwim Delta. Causes of this rapid and continuing decline of -14% per year are undocumented. Many aspects of spectacled eider biology remain unknown, including their marine foraging habitats, food items, migratory movements, and population ecology. A review of some biological characteristics and possible threats to the species suggests the importance of quantifying potential impacts from parasites and disease, subsistence harvest, predation during brood rearing, and alteration of Bering Sea food resources. Factors causing the population decline of spectacled eiders must be determined and appropriate actions taken to reverse the trend.Key words: Alaska, declining species, Somateria fischeri, spectacled eider, waterfowl, Yukon-Kuskokwim DeltaLes populations d'eider à lunettes (Somateria fischeri) de l'Alaska occidental s'élèvent maintenant à moins de 4 p. cent du total estimé au début des années 70. En 1992, on a estimé à 1721 le nombre de paires nicheuses qui restaient dans le delta du Yukon-Kuskokwim. Les causes de ce déclin rapide et continu de -14 p. cent par an ne sont pas documentées. Bien des aspects de la biologie de l'eider à lunettes restent inconnus, y compris l'habitat marin où il trouve sa nourriture, ses aliments, ses déplacements migratoires et l'écologie de la population. Un examen de certaines caractéristiques biologiques et des menaces dont l'espèce pourrait faire l'objet suggère l'importance qu'il y a à quantifier les retombées potentielles des parasites et des maladies, des récoltes destinées à assurer la subsistance, de la prédation durant l'élevage de la couvée et des changements dans les ressources alimentaires de la mer de Béring. Il faut déterminer les facteurs responsables du déclin de la population de l'eider à lunettes et prendre les mesures qui s'imposent pour renverser la tendance.Mots clés : Alaska, espèce en déclin, Somateria fischeri, eider à lunettes, oiseau aquatique, delta du Yukon-Kuskokwi

Structure of the Proline Utilization A Proline Dehydrogenase Domain Inactivated by \u3ci\u3eN\u3c/i\u3e-propargylglycine Provides Insight into Conformational Changes Induced by Substrate Binding and Flavin Reduction

Proline utilization A (PutA) from Escherichia coli is a flavoprotein that has mutually exclusive roles as a transcriptional repressor of the put regulon and a membrane-associated enzyme that catalyzes the oxidation of proline to glutamate. Previous studies have shown that the binding of proline in the proline dehydrogenase (PRODH) active site and subsequent reduction of the FAD trigger global conformational changes that enhance PutA-membrane affinity. These events cause PutA to switch from its repressor to enzymatic role, but the mechanism by which this signal is propagated from the active site to the distal membrane-binding domain is largely unknown. Here, it is shown that N-propargylglycine irreversibly inactivates PutA by covalently linking the flavin N(5) atom to the ε-amino of Lys329. Furthermore, inactivation locks PutA into a conformation that may mimic the proline reduced, membrane-associated form. The 2.15 Å resolution structure of the inactivated PRODH domain suggests that the initial events involved in broadcasting the reduced flavin state to the distal membrane binding domain include major reorganization of the flavin ribityl chain, severe (35 degree) butterfly bending of the isoalloxazine ring, and disruption of an electrostatic network involving the flavin N(5), Arg431, and Asp370. The structure also provides information about conformational changes associated with substrate binding. This analysis suggests that the active site is incompletely assembled in the absence of the substrate, and the binding of proline draws together conserved residues in helix 8 and the β1-αl loop to complete the active site