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Background: There is presently no cure for locomotor deficits after spinal cord injury (SCI). Very few therapies effectively target the brain due to poor understanding of the brain’s role post-SCI. Newly developed tissue clearing techniques have permitted unbiased three-dimensional circuit analysis, opening new opportunities for SCI-related brain interrogation. Methods: We established a novel brain interrogation pipeline by optimizing mouse brain clearing, imaging, and atlas registration. We leveraged a spontaneous recovery lateral hemisection model to analyze whole brain cell activity and connectivity with the lumbar cord using cFos immunolabelling and virus-mediated projection tracing. We identified a functionally and anatomically dynamic region correlating with recovery and interrogated its locomotor role with optogenetics. We assessed deep brain electrical stimulation (DBS) of this region in a more clinically relevant rat contusion SCI using an established bipedal robotic interface. Results: We unexpectedly uncovered the lateral hypothalamus (LH) to functionally and anatomically correlate with recovery. LHVglut2 optogenetic stimulation significantly augmented locomotor function. LH DBS in rats acutely robustly augmented bipedal locomotion post-SCI. Conclusions: This is the first demonstration of the LH’s role in locomotion post-SCI and is a novel DBS target that robustly augmented locomotor function, dependent on LH glutamatergic cells. LH DBS may be a promising intervention in humans.
A new acanthocladiid bryozoan genus from the Permian of the Glass Mountains of Texas, U.S.A., reveals a distinctive morphology and a growth pattern unique amongst members of the extinct stenolaemate Order Fenestrata. Adlatipora fossulata n. gen. n. sp. forms small pinnate expansions with moderately robust main stems and shorter laterally placed pinnae. Colonies developed from small basal discs that exhibit a unique multilayered skeletal structure, from which a circlet of first generation autozooids bud from the ancestrula; these become the bases of branches. In Adlatipora autozooecia are organized into diagonal rows that alternate along branches and are separated into right-handed or left-handed forms. A fossula is developed from the distal margin of autozooecial apertures. Proximal pores are located adjacent to autozooecial apertures and are remnants of fossulae. These pores probably acted as an anal pore providing a passageway for fecal products.
We present the first closed-loop separation control experiment using a novel, model-free strategy based on genetic programming, which we call ‘machine learning control’. The goal is to reduce the recirculation zone of backward-facing step flow at $\mathit{Re}_{h}=1350$ manipulated by a slotted jet and optically sensed by online particle image velocimetry. The feedback control law is optimized with respect to a cost functional based on the recirculation area and a penalization of the actuation. This optimization is performed employing genetic programming. After 12 generations comprised of 500 individuals, the algorithm converges to a feedback law which reduces the recirculation zone by 80 %. This machine learning control is benchmarked against the best periodic forcing which excites Kelvin–Helmholtz vortices. The machine learning control yields a new actuation mechanism resonating with the low-frequency flapping mode instability. This feedback control performs similarly to periodic forcing at the design condition but outperforms periodic forcing when the Reynolds number is varied by a factor two. The current study indicates that machine learning control can effectively explore and optimize new feedback actuation mechanisms in numerous experimental applications.
Closed-loop control of an amplifier flow is experimentally investigated. A feed-forward algorithm is implemented to control the flow downstream of a backward-facing step (BFS) perturbed by upstream perturbations. Upstream and downstream data are extracted from real-time velocity fields to compute an ARMAX model used to effect actuation. This work, done at Reynolds number 430, investigates the practical feasibility of this approach which has shown great promise in a recent numerical study by Hervé et al. (J. Fluid Mech., vol. 702, 2012, pp. 26–58). The linear nature of the regime is checked, two-dimensional upstream perturbations are introduced, and the degree to which the flow can be controlled is quantified. The resulting actuation is able to effectively reduce downstream energy levels and fluctuations. The limitations and difficulties of applying such an approach to an experiment are also discussed.
Developments of composites materials had begun in the 1970's. They aimed in improving mechanical properties due to the presence of reinforcement particles. The addition of particles in a matrix led to different modifications: considering the nature of the phases and the microstructure, we can mention interface reactivity between matrix and particles, changes in the chemical composition of the matrix and modified kinetics of microstructure evolution in the matrix (as compared to the matrix without particles); considering the mechanical aspects, thermal stresses may be generated due to the differences in expansion coefficients between the particles and the matrix, or any changes in the matrix leading to a phase transformation. In the present work, we studied the evolution of the phases and the behavior of a steel based MMC during thermal treatments, for which a phase transformation occurred on cooling. Experiments and numerical simulation are considered.
We report here on the coupling of a gas reactor with a VUV beamline at the SOLEILsynchrotron radiation facility. The reactor may be irradiated window-less with gaspressure up to the atmosphere. The photochemistry is monitored by a mass spectrometer gasanalyzer. This set up, termed APSIS for Atmospheric Photochemistry SImulated bySynchrotron, has been used to simulate the atmosphere of Titan and to study the formationof the photochemical smog and the formation of tholins.
We present the latest results of our on-going closed-loop “end-to-end” numerical adaptive optics (AO) simulations concerning both a standard-AO and a three-star ground-layer AO system for a near-infrared 2-m class telescope at Dome C, Antarctica. We demonstrate that Dome C is an ideal site for wide-field AO-aided astronomy, define in details the AO system(s) optimized for the median turbulence profile considered, and finally show that a ~0.3 Strehl ratio and 200-mas-wide stable point-spread function is reached in band J on at least a 15'-diameter field.
Chemically Peculiar (CP) stars have been the subject of systematic research for more than 50 years. With the discovery of pulsation of some of the cool CP stars, and the availability of advanced spectropolarimetric instrumentation and high signal-to-noise, high resolution spectroscopy, a new era of CP star research emerged about 20 years ago. Together with the success in ground-based observations, new space projects are developed that will greatly benefit future investigations of these unique objects. In this contribution we will give an overview of some interesting results obtained recently from ground-based observations and discuss the future outstanding Gaia space mission and its impact on CP star research.
GaN epilayers were grown by metal-organic vapor phase epitaxy (MOVPE) on z- and x-cut lithium niobate substrates. Ex-situ characterizations of the epilayers by means of scanning electron microscope, atomic force microscope, X-ray diffraction and micro-Raman scattering measurements have revealed same growth features on both substrates. The observation of the morphology shows homogeneous and relatively smooth surface. The shape and density of GaN islands as well as the observed columnar growth mode are not dependent of the orientation of the LN substrates. The X-ray diffraction analysis of 450 nm thick GaN layers grown at 730 °C on z- and x-cuts showed that both GaN layers reveal the same crystallographic orientation, i.e. c-axis orientation normal to the substrate plane and in-plane orientation that coincides with the primary axis of LN substrates. The Raman scattering measurements confirm the growth of an oriented epitaxial GaN layer on LN substrate. Moreover, the deposited layer exhibit a quite good homogeneity, since the Raman spectra recorded for different positions in the layer do not reveal any significant variations in their relative intensities and frequency shifts.
The Kepler Mission is a space-based mission whose primary goal is to determine the frequency of Earth-size and larger planets in the habitable zone of solar-like stars. The mission will monitor more than 100,000 stars for patterns of transits with a differential photometric precision of 20 ppm at V = 12 for a 6.5 hour transit. It will also provide asteroseismic results on several thousand dwarf stars. It is specifically designed to continuously observe a single field of view of greater than 100 square degrees for 3.5 or more years.
This paper provides a short overview of the mission, a brief history of the mission development, expected results, new investigations by the recently chosen Participating Scientists, and the plans for the Guest Observer and Astrophysical Data Programs.
The Kepler Mission is a space-based mission whose primary goal is to detect Earth-size and smaller planets in the habitable zone of solar-like stars. The mission will monitor more than 100,000 stars for transits with a differential photometric precision of 20 ppm at V=12 for a 6.5 hour transit. It will also provide asteroseismic results on several thousand dwarf stars. It is specifically designed to continuously observe a single field of view of greater than 100 square degrees for 3.5 or more years.
This overview describes the mission design, its goals and capabilities, the measured performance for those photometer components that have now been tested, the Kepler Input Catalog, an overview of the analysis pipeline, the plans for the Follow-up Observing Program to validate the detections and characterize the parent stars, and finally, the plans for the Guest Observer and Astrophysical Data Program.
The Kepler Mission is a space-based photometric mission with a differential photometric precision of 14 ppm (at V = 12 for a 6.5 hour transit). It is designed to continuously observe a single field of view (FOV) of greater then 100 square degrees in the Cygnus-Lyra region for four or more years. The primary goal of the mission is to monitor more than one-hundred thousand stars for transits of Earth-size and smaller planets in the habitable zone of solar-like stars. In the process, many eclipsing binaries (EB) will also be detected and light curves produced. To enhance and optimize the mission results, the stellar characteristics for all the stars in the Kepler FOV with V < 16 will have been determined prior to launch. As part of the verification process, stars with transit candidates will have radial-velocity follow-up observations performed to determine the component masses and thereby separate eclipses caused by stellar companions from transits caused by planets. The result will be a rich database on EBs. The community will have access to the archive for further analysis, such as, for EB modeling of the high-precision light curves. A guest observer program is also planned to allow for photometric observations of objects not on the target list but within the FOV.
We report preliminary results from a deep I-band optical search for substellar candidates in the p Oph star-forming region. The dusty molecular cloud provides an opaque screen at optical wavelengths, making the survey sensitive to faint substellar candidates near the cloud surface. Of the 89 objects detected in the oph A and oph C molecular cores, one third are substellar candidates.
We present results from a near-infrared array, CO interferometer, and H2O maser interferometer survey of the circumstellar environments of 26 young low-luminosity embedded stars located in nearby molecular clouds. About 75% of the sample show evidence for stellar winds/outflows in the near-infrared or CO data indicating that most of these sources are in the early wind clearing phase of their evolution. Close to 15% are multiple on the scale of 20″, suggesting that fragmentation of their surrounding dense cloud cores is important before or during gravitational collapse. Roughly 10% have H2O maser emission and the kinematics imply the masers arise in gravitationally unbound gas (i.e., a stellar wind or outflow) rather than in a circumstellar disk.