225 research outputs found
Distribution Patterns of Eastern Red-Cedar Juniperus virginiana L. in Henry County, Iowa
The distribution patterns of Eastern red-cedar were studied in Henry County, Iowa, in a general survey and also in three intensive study areas in Marion, Jackson, and Wayne townships. It was found that the abundant seed sources of red-cedar and the predominantly rolling land in Henry County make extensive establishment of red-cedars possible. In the northern tier of townships red-cedars are restricted to fence lines and roadsides whereas in the hilly southern three tiers of townships they are much more abundant
Wearable Inertial Measurement Units for Assessing Gait in Real-World Environments
Walking patterns can provide important indications of a personâs health status and be beneficial in the early diagnosis of individuals with a potential walking disorder. For appropriate gait analysis, it is critical that natural functional walking
characteristics are captured, rather than those experienced in artificial or observed settings. To better understand the extent to which setting influences gait patterns, and particularly whether observation plays a varying role on subjects of different ages, the current study investigates to what extent people walk differentl
Effect of NASA Light-emitting Diode Irradiation on Wound Healing
Objective: The purpose of this study was to assess the effects of hyperbaric oxygen (HBO) and near-infrared light therapy on wound healing.
Background Data: Light-emitting diodes (LED), originally developed for NASA plant growth experiments in space show promise for delivering light deep into tissues of the body to promote wound healing and human tissue growth. In this paper, we review and present our new data of LED treatment on cells grown in culture, on ischemic and diabetic wounds in rat models, and on acute and chronic wounds in humans.
Materials and Methods: In vitro and in vivo (animal and human) studies utilized a variety of LED wavelength, power intensity, and energy density parameters to begin to identify conditions for each biological tissue that are optimal for biostimulation.
Results: LED produced in vitro increases of cell growth of 140â200% in mouse-derived fibroblasts, rat-derived osteoblasts, and rat-derived skeletal muscle cells, and increases in growth of 155â171% of normal human epithelial cells. Wound size decreased up to 36% in conjunction with HBO in ischemic rat models. LED produced improvement of greater than 40% in musculoskeletal training injuries in Navy SEAL team members, and decreased wound healing time in crew members aboard a U.S. Naval submarine. LED produced a 47% reduction in pain of children suffering from oral mucositis.
Conclusion: We believe that the use of NASA LED for light therapy alone, and in conjunction with hyperbaric oxygen, will greatly enhance the natural wound healing process, and more quickly return the patient to a preinjury/ illness level of activity. This work is supported and managed through the NASA Marshall Space Flight CenterâSBIR Program
Tiny Sc allows the chains to rattle: Impact of Lu and Y doping on the charge density wave in ScVSn
The kagome metals display an intriguing variety of electronic and magnetic
phases arising from the connectivity of atoms on a kagome lattice. A growing
number of these materials with vanadium kagome nets host charge density waves
(CDWs) at low temperatures including ScVSn, CsVSb, and
VSb. Curiously, only the Sc version of the VSn
HfFeGe-type materials hosts a CDW (Gd-Lu, Y, Sc). In this study
we investigate the role of rare earth size in CDW formation in the
VSn compounds. Magnetization measurements on our single crystals of
(Sc,Lu)VSn and (Sc,Y)VSn establish that the CDW is suppressed
by substitution of Sc by larger Lu or Y. Single crystal x-ray diffraction
reveals that compressible Sn-Sn bonds accommodate the larger rare earth atoms
within loosely packed -Sn-Sn chains without significantly expanding the
lattice. We propose that Sc provides the extra room in these chains crucial to
CDW formation in ScVSn. Our rattling chain model explains why both
physical pressure and substitution by larger rare earths hinder CDW formation
despite opposite impacts on lattice size. We emphasize the cooperative effect
of pressure and rare earth size by demonstrating that pressure further
suppresses the CDW in a Lu-doped ScVSn crystal. Our model not only
addresses why a CDW only forms in the VSn materials with tiny Sc, it
also advances to our understanding of why unusual CDWs form in the kagome
metals.Comment: 28 pages, 9 figures, crystallographic information files for LuV6Sn6
and YV6Sn6 along with supplemental materials in ancillary file
Tele-Operated Lunar Rover Navigation Using Lidar
Near real-time tele-operated driving on the lunar surface remains constrained by bandwidth and signal latency despite the Moon s relative proximity. As part of our work within NASA s Human-Robotic Systems Project (HRS), we have developed a stand-alone modular LIDAR based safeguarded tele-operation system of hardware, middleware, navigation software and user interface. The system has been installed and tested on two distinct NASA rovers-JSC s Centaur2 lunar rover prototype and ARC s KRex research rover- and tested over several kilometers of tele-operated driving at average sustained speeds of 0.15 - 0.25 m/s around rocks, slopes and simulated lunar craters using a deliberately constrained telemetry link. The navigation system builds onboard terrain and hazard maps, returning highest priority sections to the off-board operator as permitted by bandwidth availability. It also analyzes hazard maps onboard and can stop the vehicle prior to contacting hazards. It is robust to severe pose errors and uses a novel scan alignment algorithm to compensate for attitude and elevation errors
Recurrent intragenic rearrangements of EGFR and BRAF in soft tissue tumors of infants.
Soft tissue tumors of infancy encompass an overlapping spectrum of diseases that pose unique diagnostic and clinical challenges. We studied genomes and transcriptomes of cryptogenic congenital mesoblastic nephroma (CMN), and extended our findings to five anatomically or histologically related soft tissue tumors: infantile fibrosarcoma (IFS), nephroblastomatosis, Wilms tumor, malignant rhabdoid tumor, and clear cell sarcoma of the kidney. A key finding is recurrent mutation of EGFR in CMN by internal tandem duplication of the kinase domain, thus delineating CMN from other childhood renal tumors. Furthermore, we identify BRAF intragenic rearrangements in CMN and IFS. Collectively these findings reveal novel diagnostic markers and therapeutic strategies and highlight a prominent role of isolated intragenic rearrangements as drivers of infant tumors
The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe
The preponderance of matter over antimatter in the early Universe, the
dynamics of the supernova bursts that produced the heavy elements necessary for
life and whether protons eventually decay --- these mysteries at the forefront
of particle physics and astrophysics are key to understanding the early
evolution of our Universe, its current state and its eventual fate. The
Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed
plan for a world-class experiment dedicated to addressing these questions. LBNE
is conceived around three central components: (1) a new, high-intensity
neutrino source generated from a megawatt-class proton accelerator at Fermi
National Accelerator Laboratory, (2) a near neutrino detector just downstream
of the source, and (3) a massive liquid argon time-projection chamber deployed
as a far detector deep underground at the Sanford Underground Research
Facility. This facility, located at the site of the former Homestake Mine in
Lead, South Dakota, is approximately 1,300 km from the neutrino source at
Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino
charge-parity symmetry violation and mass ordering effects. This ambitious yet
cost-effective design incorporates scalability and flexibility and can
accommodate a variety of upgrades and contributions. With its exceptional
combination of experimental configuration, technical capabilities, and
potential for transformative discoveries, LBNE promises to be a vital facility
for the field of particle physics worldwide, providing physicists from around
the globe with opportunities to collaborate in a twenty to thirty year program
of exciting science. In this document we provide a comprehensive overview of
LBNE's scientific objectives, its place in the landscape of neutrino physics
worldwide, the technologies it will incorporate and the capabilities it will
possess.Comment: Major update of previous version. This is the reference document for
LBNE science program and current status. Chapters 1, 3, and 9 provide a
comprehensive overview of LBNE's scientific objectives, its place in the
landscape of neutrino physics worldwide, the technologies it will incorporate
and the capabilities it will possess. 288 pages, 116 figure
Effects of branching spatial structure and life history on the asymptotic growth rate of a population
Author Posting. © The Author(s), 2009. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Theoretical Ecology 3 (2010): 137-152, doi:10.1007/s12080-009-0058-0.The dendritic structure of a river network creates directional dispersal and a hierarchical
arrangement of habitats. These two features have important consequences for the
ecological dynamics of species living within the network.We apply matrix population models to a stage-structured population in a network of habitat patches connected in a dendritic
arrangement. By considering a range of life histories and dispersal patterns, both constant
in time and seasonal, we illustrate how spatial structure, directional dispersal, survival, and
reproduction interact to determine population growth rate and distribution. We investigate
the sensitivity of the asymptotic growth rate to the demographic parameters of the model,
the system size, and the connections between the patches. Although some general patterns
emerge, we find that a speciesâ mode of reproduction and dispersal are quite important in its
response to changes in its life history parameters or in the spatial structure. The framework
we use here can be customized to incorporate a wide range of demographic and dispersal
scenarios.Funding for this work came from the James S. McDonnell Foundation (EEG, HJL, WFF). MGN was supported by grants from the National Science Foundation (CMG-0530830, OCE-0326734, ATM-0428122)
Characterization of Geographical and Meteorological Parameters
[EN]This chapter is devoted to the introduction of some geographical and meteorological information involved in the numerical modeling of wind fields and solar radiation. First, a brief description of the topographical data given by a Digital Elevation Model and Land Cover databases is provided. In particular, the Information System of Land Cover of Spain (SIOSE) is considered. The study is focused on the roughness length and the displacement height parameters that appear in the logarithmic wind profile, as well as in the albedo related to solar radiation computation. An extended literature review and characterization of both parameters are reported. Next, the concept of atmospheric stability is introduced from the MoninâObukhov similarity theory to the recent revision of Zilitinkevich of the Neutral and Stable Boundary Layers (SBL). The latter considers the effect of the free-flow static stability and baroclinicity on the turbulent transport of momentum and of the Convective Boundary Layers (CBL), more precisely, the scalars in the boundary layer, as well as the model of turbulent entrainment
Micromechanical Properties of Injection-Molded StarchâWood Particle Composites
The micromechanical properties of injection molded starchâwood particle composites were investigated as a function of particle content and humidity conditions.
The composite materials were characterized by scanning electron microscopy and X-ray diffraction methods. The microhardness
of the composites was shown to increase notably with the concentration of the wood particles. In addition,creep behavior under the indenter and temperature dependence
were evaluated in terms of the independent contribution of the starch matrix and the wood microparticles to the hardness value. The influence of drying time on the density
and weight uptake of the injection-molded composites was highlighted. The results revealed the role of the mechanism of water evaporation, showing that the dependence of water uptake and temperature was greater for the starchâwood composites than for the pure starch sample. Experiments performed during the drying process at 70°C indicated that
the wood in the starch composites did not prevent water loss from the samples.Peer reviewe
- âŠ