175 research outputs found

    Daily Mindfulness Meditation and Exercise Impact Stress, Anxiety, and Mindfulness in Students During the Pandemic

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    Stress and anxiety are often elevated in college students and were exacerbated by the uncertainty of learning during the COVID-19 pandemic. Physical activity and mindfulness meditation are small lifestyle changes that can have a large effect on stress and anxiety. PURPOSE: Identify the effects of daily walking or daily mindfulness meditation on stress, anxiety, and mindfulness in college students during the spring 2021 semester. METHODS: Sixty-five college students were randomly assigned to three groups: control (N=22), exercise (N=24), or mindfulness (N=19). The control group did nothing in addition to their normal routine, the exercise group walked 15 minutes every day, and the mindfulness group completed a 10-to-12-minute daily mindfulness meditation. Most participants identified as female (84.7%) and as non-Hispanic/white (87.3%), and all ranged from 18 to 22 years old. The Perceived Stress Scale, Spielberger State-Trait Anxiety Inventory, and the Five Facet Mindfulness Questionnaire were completed by participants before and after the six-week intervention. Participants also reported their daily physical activity during the six-week intervention. RESULTS: Overall, there were significant improvements in stress (t(64)= 3.77; p\u3c.001), anxiety (t(64) =2.75; p\u3c.001), and mindfulness (t(63)=-4.69; p=0.004) from baseline to post-test. The daily walking group experienced a significant increase in mindfulness (t(23)=-3.41; p=.002; d=l 1.0) and a non-significant improvement in stress (t(23)=2.01; p=.056; d=5.38). The daily meditation group experienced a significant improvement in stress (t(18)=3.07; p=.007; d=5.46), anxiety (t(18)=2.86; p=.010; d=12.1), and mindfulness (t(l 7)=-3.62; p=.002; d=12.1). The control group experienced no significant changes in stress (t(21)=1.45; p=.162; d=4.71), anxiety (t(21)=.683; p=.502; d=l2.8), nor mindfulness (t(21)=-1.25; p=.225; d=l 1.3). Although there were some individual group differences over time, there were no significant interactions between time and group for stress (F(2,62)=1.12; p=.334), anxiety (F(2,62)=1.16; p=.319), nor mindfulness (F(2,61)=2.15; p=.125). Physical activity was not significantly different between groups over time (F(7 .13,214 )= .694; p= .680). CONCLUSION: Daily exercise and mindfulness meditation improved mindfulness and stress in college students while the latter intervention also had a significant impact on anxiety. These short, daily practices have potential to be incorporated into students\u27 lives to enhance quality of life and improve mental health, especially during uncertain and challenging situations

    Pupil Alignment Considerations for Large, Deployable Space Telescopes

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    For many optical systems the properties and alignment of the internal apertures and pupils are not critical or controlled with high precision during optical system design, fabrication or assembly. In wide angle imaging systems, for instance, the entrance pupil position and orientation is typically unconstrained and varies over the system s field of view in order to optimize image quality. Aperture tolerances usually do not receive the same amount of scrutiny as optical surface aberrations or throughput characteristics because performance degradation is typically graceful with misalignment, generally only causing a slight reduction in system sensitivity due to vignetting. But for a large deployable space-based observatory like the James Webb Space Telescope (JWST), we have found that pupil alignment is a key parameter. For in addition to vignetting, JWST pupil errors cause uncertainty in the wavefront sensing process that is used to construct the observatory on-orbit. Furthermore they also open stray light paths that degrade the science return from some of the telescope s instrument channels. In response to these consequences, we have developed several pupil measurement techniques for the cryogenic vacuum test where JWST science instrument pupil alignment is verified. These approaches use pupil alignment references within the JWST science instruments; pupil imaging lenses in three science instrument channels; and unique pupil characterization features in the optical test equipment. This will allow us to verify and crosscheck the lateral pupil alignment of the JWST science instruments to approximately 1-2% of their pupil diameters

    Testing and Calibration of Phase Plates for JWST Optical Simulator

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    Three phase plates were designed to simulate the JWST segmented primary mirror wavefront at three on-orbit alignment stages: coarse phasing, intermediate phasing, and fine phasing. The purpose is to verify JWST's on-orbit wavefront sensing capability. Amongst the three stages, coarse alignment is defined to have piston error between adjacent segments being 30 m to 300 m, intermediate being 0.4 m to 10 m, and fine is below 0.4 m. The phase plates were made of fused silica, and were assembled in JWST Optical Simulator (OSIM). The piston difference was realized by the thickness difference of two adjacent segments. The two important parameters to phase plates are piston and wavefront errors. Dispersed Fringe Sensor (DFS) method was used for initial coarse piston evaluation, which is the emphasis of this paper. Point Diffraction Interferometer (PDI) is used for fine piston and wavefront error. In order to remove piston's 2 pi uncertainty with PDI, three laser wavelengths, 640nm, 660nm, and 780nm, are used for the measurement. The DHS test setup, analysis algorithm and results are presented. The phase plate design concept and its application (i.e. verifying the JWST on-orbit alignment algorithm) are described. The layout of JWST OSIM and the function of phase plates in OSIM are also addressed briefly

    Absolute Position of Targets Measured Through a Chamber Window Using Lidar Metrology Systems

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    Lidar is a useful tool for taking metrology measurements without the need for physical contact with the parts under test. Lidar instruments are aimed at a target using azimuth and elevation stages, then focus a beam of coherent, frequency modulated laser energy onto the target, such as the surface of a mechanical structure. Energy from the reflected beam is mixed with an optical reference signal that travels in a fiber path internal to the instrument, and the range to the target is calculated based on the difference in the frequency of the returned and reference signals. In cases when the parts are in extreme environments, additional steps need to be taken to separate the operator and lidar from that environment. A model has been developed that accurately reduces the lidar data to an absolute position and accounts for the three media in the testbed air, fused silica, and vacuum but the approach can be adapted for any environment or material. The accuracy of laser metrology measurements depends upon knowing the parameters of the media through which the measurement beam travels. Under normal conditions, this means knowledge of the temperature, pressure, and humidity of the air in the measurement volume. In the past, chamber windows have been used to separate the measuring device from the extreme environment within the chamber and still permit optical measurement, but, so far, only relative changes have been diagnosed. The ability to make accurate measurements through a window presents a challenge as there are a number of factors to consider. In the case of the lidar, the window will increase the time-of-flight of the laser beam causing a ranging error, and refract the direction of the beam causing angular positioning errors. In addition, differences in pressure, temperature, and humidity on each side of the window will cause slight atmospheric index changes and induce deformation and a refractive index gradient within the window. Also, since the window is a dispersive media, the effect of both phase and group indices have to be considered. Taking all these factors into account, a method was developed to measure targets through multiple regions of different materials and produce results that are absolute measurements of target position in three-dimensional space, rather than simply relative position. The environment in which the lidar measurements are taken must be broken down into separate regions of interest and each region solved for separately. In this case, there were three regions of interest: air, fused silica, and vacuum. The angular position of the target inside the chamber is solved using only phase index and phase velocity, while the ranging effects due to travel from air to glass to vacuum/air are solved with group index and group velocity. When all parameters are solved simultaneously, an absolute knowledge of the position of each target within an environmental chamber can be derived. Novel features of this innovation include measuring absolute position of targets through multiple dispersive and non-dispersive media, deconstruction of lidar raw data from a commercial off-the-shelf unit into reworkable parameters, and use of group velocities to reduce range data. Measurement of structures within a vacuum chamber or other harsh environment, such as a furnace, may now be measured as easily as if they were in an ambient laboratory. This analysis permits transformation of the raw data into absolute spatial units (e.g., mm). This technique has also been extended to laser tracker, theodolite, and cathetometer measurements through refractive media

    Cryogenic Pupil Alignment Test Architecture for Aberrated Pupil Images

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    A document describes cryogenic test architecture for the James Webb Space Telescope (JWST) integrated science instrument module (ISIM). The ISIM element primarily consists of a mechanical metering structure, three science instruments, and a fine guidance sensor. One of the critical optomechanical alignments is the co-registration of the optical telescope element (OTE) exit pupil with the entrance pupils of the ISIM instruments. The test architecture has been developed to verify that the ISIM element will be properly aligned with the nominal OTE exit pupil when the two elements come together. The architecture measures three of the most critical pupil degrees-of-freedom during optical testing of the ISIM element. The pupil measurement scheme makes use of specularly reflective pupil alignment references located inside the JWST instruments, ground support equipment that contains a pupil imaging module, an OTE simulator, and pupil viewing channels in two of the JWST flight instruments. Pupil alignment references (PARs) are introduced into the instrument, and their reflections are checked using the instrument's mirrors. After the pupil imaging module (PIM) captures a reflected PAR image, the image will be analyzed to determine the relative alignment offset. The instrument pupil alignment preferences are specularly reflective mirrors with non-reflective fiducials, which makes the test architecture feasible. The instrument channels have fairly large fields of view, allowing PAR tip/tilt tolerances on the order of 0.5deg

    Retinoids regulate TGFβ signaling at the level of Smad2 phosphorylation and nuclear accumulation

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    AbstractIndirect regulation of transforming growth factor (TGF)-β signaling by retinoids occurs on a long-term timescale, secondary to transcriptional events. Studies by our group show loss of retinoid X receptor (RXR) alpha results in increased TGFβ2 in the midgestational heart, which may play a role in the cardiac defects seen in this model [S.W. Kubalak, D.R. Hutson, K.K. Scott and R.A. Shannon, Elevated transforming growth factor beta2 enhances apoptosis and contributes to abnormal outflow tract and aortic sac development in retinoic X receptor alpha knockout embryos, Development 129 (2002) 733–746.]. Acute and direct interactions between retinoid and TGFβ signaling, however, are not clearly understood. Treatment of dispersed hearts and NIH3T3 cells for 1 h with TGFβ and retinoids (dual treatment) resulted in increased phosphorylated Smad2 and Smad3 when compared to treatment with TGFβ alone. Of all dual treatments, those with the RXR agonist Bexarotene, resulted in the highest level of phosphorylated Smad2, a 7-fold increase over TGFβ2 alone. Additionally, during dual treatment phosphorylation of Smad2 occurs via the TGFβ type I receptor but not by increased activation of the receptor. As loss of RXRα results in increased levels of Smad2 phosphorylation in response to TGFβ treatment and since nuclear accumulation of phosphorylated Smad2 is decreased during dual treatment, we propose that RXRα directly regulates the activities of Smad2. These data show retinoid signaling influences the TGFβ pathway in an acute and direct manner that has been unappreciated until now

    Laser Radar Through the Window (LRTW) Coordinate Correction Method

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    A method for corrections of measurements of points of interests measured by beams of radiation propagating through stratified media including performance of ray-tracing of at least one ray lunched from a metrology instrument in a direction of an apparent point of interest, calculation a path length of the ray through stratified medium, and determination of coordinates of true position of the point interest using the at least one path length and the direction of propagation of the ray

    A Scanning Hartmann Focus Test for the EUVI Telescopes aboard STEREO

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    The Solar TErrestrial RElations Observatory (STEREO), the third mission in NASA's Solar Terrestrial Probes program, was launched in 2006 on a two year mission to study solar phenomena. STEREO consists of two nearly identical satellites, each carrying an Extreme Ultraviolet Imager (EUVI) telescope as part of the Sun Earth Connection Coronal and Heliospheric Investigation instrument suite. EUVI is a normal incidence, 98mm diameter, Ritchey-Chretien telescope designed to obtain wide field of view images of the Sun at short wavelengths (17.1-30.4nm) using a CCD detector. The telescope entrance aperture is divided into four quadrants by a mask near the secondary mirror spider veins. A mechanism that rotates another mask allows only one of these sub-apertures to accept light over an exposure. The EUVI contains no focus mechanism. Mechanical models predict a difference in telescope focus between ambient integration conditions and on-orbit operation. We describe an independent check of the ambient, ultraviolet, absolute focus setting of the EUVI telescopes after they were integrated with their respective spacecraft. A scanning Hartmann-like test design resulted from constraints implied by the EUVI aperture select mechanism. This inexpensive test was simultaneously coordinated with other NASA integration and test activities in a high-vibration, clean room environment. The total focus test error was required to be better than +/-0.05 mm. We describe the alignment and test procedure, sources of statistical and systematic error, and then the focus determination results using various algorithms. The results are consistent with other tests of focus alignment and indicate that the EUVI telescopes meet the ambient focus offset requirements. STEREO is functioning well on-orbit and the EUVI telescopes meet their on-orbit image quality requirements

    Cryogenic Thermal Vacuum Testing with Remote Optical Metrology

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    Flexure Engineering was awarded an SBIR to research and develop technology needed to build a thermal vacuum chamber made to take laser radar metrology through a window. The XATF test is proof of concept for this, and demonstrated the need for such a chamber. XATF refers to two pieces of critical ground support equipment for NASA's JWST (James Webb Space Telescope) Integrated Science Instrument Module (ISIM), the ISIM Alignment Target Fixture (IATF) and the Master Alignment Target Fixture (MATF). These optical alignment assemblies require characterization while under cryogenic temperature. A thermal vacuum chamber equipped with a shroud cooled with gaseous and liquid nitrogen was used. An inner shroud was cooled with liquid helium to approximately 30K. The XATF assemblies were kinematically mounted and oriented inside the inner shroud such that the optical targets were visible from outside an optical window on one of the chamber ports. Laser radar and theodolite mounted outside the window took measurements of various optical targets. Two cold cycles were completed. A third cycle was aborted. Metrology was successfully taken. There were some problems with the helium system. The cryo pumps were turned off to reduce vibrations during metrology. Many new technologies and testing methods must be developed for JWST and future programs that will require precision measurements. These technologies will be applicable to other cold temperature applications, such as lunar missions and superconductors. Remote metrology technologies can also be applicable to testing in harsh environments. Facilities with remote metrology capability will be valuable
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