Optical Testing of Retroreflectors for Cryogenic Applications

A laser tracker (LT) is an important coordinate metrology tool that uses laser interferometry to determine precise distances to objects, points, or surfaces defined by an optical reference, such as a retroreflector. A retroreflector is a precision optic consisting of three orthogonal faces that returns an incident laser beam nearly exactly parallel to the incident beam. Commercial retroreflectors are designed for operation at room temperature and are specified by the divergence, or beam deviation, of the returning laser beam, usually a few arcseconds or less. When a retroreflector goes to extreme cold (.35 K), however, it could be anticipated that the precision alignment between the three faces and the surface figure of each face would be compromised, resulting in wavefront errors and beam divergence, degrading the accuracy of the LT position determination. Controlled tests must be done beforehand to determine survivability and these LT coordinate errors. Since conventional interferometer systems and laser trackers do not operate in vacuum or at cold temperatures, measurements must be done through a vacuum window, and care must be taken to ensure window-induced errors are negligible, or can be subtracted out. Retroreflector holders must be carefully designed to minimize thermally induced stresses. Changes in the path length and refractive index of the retroreflector have to be considered. Cryogenic vacuum testing was done on commercial solid glass retroreflectors for use on cryogenic metrology tasks. The capabilities to measure wavefront errors, measure beam deviations, and acquire laser tracker coordinate data were demonstrated. Measurable but relatively small increases in beam deviation were shown, and further tests are planned to make an accurate determination of coordinate errors

Time Required for Lameness Detection on an Embedded Microcomputer Based Force Plate in a Lab Based Setting

The objective of this study was to determine the minimum time required for the embedded microcomputer based force plate (force plate) to detect lameness. The force plate can be placed under an electronic sow feeder or a gestation stall to routinely assess lameness. Previous work with the force plate has required sows to remain standing in a gestation stall for longer than a typical feeding time allotment of 9 minutes to measure the force applied to each foot. Comparing sows’ weight distribution across time showed that an adjustment period is required before force distribution measurements are consistent, as the sows adapts to the force plate. When using a 30 second adjustment period, sows only needed to stand on the force plate for 210 seconds in order to have a consistent reading across time. This could create a labor reduction during research trials, and allow more data to be used from a commercial setting, than when using the previous times

Dynamic space utilization for lame and non-lame gestating sows estimated by the lying-standing sequence

peer-reviewedThe objective of this study was to estimate the dynamic space utilization for lame and non-lame sows using their lying-standing postural sequence profile. Eighty-five sows (parity 0.9 ± 1.14; range 0 to 4) were used. Sows were moved to a pen on 30, 60 and 90 days of gestation and a ceiling mounted camera was installed above the pen to record one lying-standing event per sow. Observations ceased when the sow lied and stood, or 2.5 h elapsed from recording commencement. Additionally, each sow was evaluated for walking lameness while moving from their gestation stall to the pen. Still frames were captured from the sows’ lying and standing sequences and were combined into a single image and measured by counting pixels from contouring the sows’ body (CONTOUR), overlaying a grid on the sow image and counting any square including any part of the sow (FULL-GRID) and only counting any square that was half full or more (HALF-GRID). The space utilized while turning around was calculated by measuring the sows’ length from snout to the base of the tail and using that length as the diameter of a circle (D-PIVOT), or as the radius of a circle (R-PIVOT). Parity was re-classified as 0, 1, and 2+. There were no observed differences in the dynamic space utilized to lie, stand or turn around between lame and non-lame sows (P > 0.05). On average, sows used 1.2 ± 0.47 m2 to lie and 1.3 ± 0.46 m2 to stand. There was no difference between the CONTOUR and HALF-GRID methods (P > 0.05); however, using the FULL-GRID sows required 0.3 m2 more floor area to lie and stand compared with the other measuring methods (P < 0.05). Space used to turn around differed between measuring method (P < 0.05). Sows required 1.9 ± 0.18 m2 for D-PIVOT and 7.3 ± 0.18 m2 for R-PIVOT to turn around. Space utilized to lie-down and stand-up increased as gestation progressed (P < 0.05). Under the conditions of this study, lameness did not influence dynamic space utilization; however, lameness recorded was relatively mild and might not have been sufficiently severe to significantly affect the results. These results could be important in decision-making process for housing specifications regarding US sow gestation housing

Bone cell-independent benefits of raloxifene on the skeleton: A novel mechanism for improving bone material properties

Authors' accepted manuscript. Bone Biology Laboratory http://www.iupui.edu/~bonelab/ Department of Anatomy and Cell Biology Indiana University School of Medicine Department of Biomedical Engineering IUPUIRaloxifene is an FDA approved agent used to treat bone loss and decrease fracture risk. In clinical trials and animal studies, raloxifene reduces fracture risk and improves bone mechanical properties, but the mechanisms of action remain unclear because these benefits occur largely independent of changes to bone mass. Using a novel experimental approach, machined bone beams, both from mature male canine and human male donors, were depleted of living cells and then exposed to raloxifene ex vivo. Our data show that ex vivo exposure of non-viable bone to raloxifene improves intrinsic toughness, both in canine and human cortical bone beams tested by 4-point bending. These effects are cell-independent and appear to be mediated by an increase in matrix bound water, assessed using basic gravimetric weighing and sophisticated ultrashort echo time magnetic resonance imaging. The hydroxyl groups (-OH) on raloxifene were shown to be important in both the water and toughness increases. Wide and small angle x-ray scattering patterns during 4-pt bending show that raloxifene alters the transfer of load between the collagen matrix and the mineral crystals, placing lower strains on the mineral, and allowing greater overall deformation prior to failure. Collectively, these findings provide a possible mechanistic explanation for the therapeutic effect of raloxifene and more importantly identify a cell-independent mechanism that can be utilized for novel pharmacological approaches for enhancing bone strength.The authors would like to thank Dr. Paul K. Hansma (Department of Physics, University of California, Santa Barbara), for suggesting the soaking technique and Dr. John Okasinski, Advanced Photon Source, for helping collect the WAXS data. Raloxifene was kindly provided by Eli Lilly (Indianapolis, IN, USA) under a Material Transfer Agreement to D.B.B. Eli Lilly was not involved in the study design, analyses or interpretation of the results. We are grateful to Dr. Susan J. Gunst for sharing dog tissue. Use of the Advanced Photon Source was supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. This work was supported by NIH grants to D.B.B. and M.R.A

The destruction and survival of dust in the shell around SN 2008S

SN 2008S erupted in early 2008 in the grand design spiral galaxy NGC 6946. The progenitor was detected by Prieto et al. in Spitzer Space Telescope images taken over the four years prior to the explosion, but was not detected in deep optical images, from which they inferred a self-obscured object with a mass of about 10 Msun. We obtained Spitzer observations of SN 2008S five days after its discovery, as well as coordinated Gemini and Spitzer optical and infrared observations six months after its outburst. We have constructed radiative transfer dust models for the object before and after the outburst, using the same r^-2 density distribution of pre-existing amorphous carbon grains for all epochs and taking light-travel time effects into account for the early post-outburst epoch. We rule out silicate grains as a significant component of the dust around SN 2008S. The inner radius of the dust shell moved outwards from its pre-outburst value of 85 AU to a post-outburst value of 1250 AU, attributable to grain vaporisation by the light flash from SN 2008S. Although this caused the circumstellar extinction to decrease from Av = 15 before the outburst to 0.8 after the outburst, we estimate that less than 2% of the overall circumstellar dust mass was destroyed. The total mass-loss rate from the progenitor star is estimated to have been (0.5-1.0)x10^-4 Msun yr^-1. The derived dust mass-loss rate of 5x10^-7 Msun yr^-1 implies a total dust injection into the ISM of up to 0.01 Msun over the suggested duration of the self-obscured phase. We consider the potential contribution of objects like SN 2008S to the dust enrichment of galaxies.Comment: 9 pages, 7 figures, 3 tables. rv2. To appear in MNRA

Psychiatry during the Nazi era: ethical lessons for the modern professional

For the first time in history, psychiatrists during the Nazi era sought to systematically exterminate their patients. However, little has been published from this dark period analyzing what may be learned for clinical and research psychiatry. At each stage in the murderous process lay a series of unethical and heinous practices, with many psychiatrists demonstrating a profound commitment to the atrocities, playing central, pivotal roles critical to the success of Nazi policy. Several misconceptions led to this misconduct, including allowing philosophical constructs to define clinical practice, focusing exclusively on preventative medicine, allowing political pressures to influence practice, blurring the roles of clinicians and researchers, and falsely believing that good science and good ethics always co-exist. Psychiatry during this period provides a most horrifying example of how science may be perverted by external forces. It thus becomes crucial to include the Nazi era psychiatry experience in ethics training as an example of proper practice gone awry

A New Highly Conserved Antibiotic Sensing/Resistance Pathway in Firmicutes Involves an ABC Transporter Interplaying with a Signal Transduction System

Signal transduction systems and ABC transporters often contribute jointly to adaptive bacterial responses to environmental changes. In Bacillus subtilis, three such pairs are involved in responses to antibiotics: BceRSAB, YvcPQRS and YxdJKLM. They are characterized by a histidine kinase belonging to the intramembrane sensing kinase family and by a translocator possessing an unusually large extracytoplasmic loop. It was established here using a phylogenomic approach that systems of this kind are specific but widespread in Firmicutes, where they originated. The present phylogenetic analyses brought to light a highly dynamic evolutionary history involving numerous horizontal gene transfers, duplications and lost events, leading to a great variety of Bce-like repertories in members of this bacterial phylum. Based on these phylogenetic analyses, it was proposed to subdivide the Bce-like modules into six well-defined subfamilies. Functional studies were performed on members of subfamily IV comprising BceRSAB from B. subtilis, the expression of which was found to require the signal transduction system as well as the ABC transporter itself. The present results suggest, for the members of this subfamily, the occurrence of interactions between one component of each partner, the kinase and the corresponding translocator. At functional and/or structural levels, bacitracin dependent expression of bceAB and bacitracin resistance processes require the presence of the BceB translocator loop. Some other members of subfamily IV were also found to participate in bacitracin resistance processes. Taken together our study suggests that this regulatory mechanism might constitute an important common antibiotic resistance mechanism in Firmicutes. [Supplemental material is available online at http://www.genome.org.

Measurements of Dihadron Correlations Relative to the Event Plane in Au+Au Collisions at sNN=200\sqrt{s_{NN}}=200 GeV

Dihadron azimuthal correlations containing a high transverse momentum (\pt) trigger particle are sensitive to the properties of the nuclear medium created at RHIC through the strong interactions occurring between the traversing parton and the medium, i.e. jet-quenching. Previous measurements revealed a strong modification to dihadron azimuthal correlations in Au+Au collisions with respect to \pp\ and \dAu\ collisions. The modification increases with the collision centrality, suggesting a path-length dependence to the jet-quenching effect. This paper reports STAR measurements of dihadron azimuthal correlations in mid-central (20-60\%) Au+Au collisions at \snn=200~GeV as a function of the trigger particle's azimuthal angle relative to the event plane, \phis=|\phit-\psiEP|. The azimuthal correlation is studied as a function of both the trigger and associated particle \pt. The subtractions of the combinatorial background and anisotropic flow, assuming Zero Yield At Minimum (\zyam), are described. The away-side correlation is strongly modified, and the modification varies with \phis, which is expected to be related to the path-length that the away-side parton traverses. The pseudo-rapidity (\deta) dependence of the near-side correlation, sensitive to long range \deta correlations (the ridge), is also investigated. The ridge and jet-like components of the near-side correlation are studied as a function of \phis. The ridge appears to drop with increasing \phis while the jet-like component remains approximately constant. ...Comment: 50 pages, 39 figures, 6 table

An Experimental Exploration of the QCD Phase Diagram: The Search for the Critical Point and the Onset of De-confinement

The QCD phase diagram lies at the heart of what the RHIC Physics Program is all about. While RHIC has been operating very successfully at or close to its maximum energy for almost a decade, it has become clear that this collider can also be operated at lower energies down to 5 GeV without extensive upgrades. An exploration of the full region of beam energies available at the RHIC facility is imperative. The STAR detector, due to its large uniform acceptance and excellent particle identification capabilities, is uniquely positioned to carry out this program in depth and detail. The first exploratory beam energy scan (BES) run at RHIC took place in 2010 (Run 10), since several STAR upgrades, most importantly a full barrel Time of Flight detector, are now completed which add new capabilities important for the interesting physics at BES energies. In this document we discuss current proposed measurements, with estimations of the accuracy of the measurements given an assumed event count at each beam energy.Comment: 59 pages, 78 figure