4,221 research outputs found
Development of Waypoint Planning Tool in Response to NASA Field Campaign Challenges
Airborne real time observations are a major component of NASA 's Earth Science research and satellite ground validation studies. Multiple aircraft are involved in most NASA field campaigns. The coordination of the aircraft with satellite overpasses, other airplanes and the constantly evolving, dynamic weather conditions often determines the success of the campaign. Planning a research aircraft mission within the context of meeting the science objectives is a complex task because it requires real time situational awareness of the weather conditions that affect the aircraft track. A flight planning tools is needed to provide situational awareness information to the mission scientists, and help them plan and modify the flight tracks. Scientists at the University of Alabama ]Huntsville and the NASA Marshall Space Flight Center developed the Waypoint Planning Tool, an interactive software tool that enables scientists to develop their own flight plans (also known as waypoints) with point -and-click mouse capabilities on a digital map filled with real time raster and vector data. The development of this Waypoint Planning Tool demonstrates the significance of mission support in responding to the challenges presented during NASA field campaigns. Analysis during and after each campaign helped identify both issues and new requirements, and initiated the next wave of development. Currently the Waypoint Planning Tool has gone through three rounds of development and analysis processes. The development of this waypoint tool is directly affected by the technology advances on GIS/Mapping technologies. From the standalone Google Earth application and simple KML functionalities, to Google Earth Plugin on web platform, and to the rising open source GIS tools with New Java Script frameworks, the Waypoint Planning Tool has entered its third phase of technology advancement. Adapting new technologies for the Waypoint Planning Tool ensures its success in helping scientist reach their mission objectives
Assessing the ecosystem services of various types of urban green spaces based on i-Tree eco
Urban green spaces play a crucial role in maintaining urban ecosystem sustainability by providing numerous ecosystem services. How to quantify and evaluate the ecological benefits and services of urban green spaces remains a hot topic currently, while the evaluation is barely applied or implemented in urban design and planning. In this study, super-high-resolution aerial images were used to acquire the spatial distribution of urban green spaces; a modified pre-stratified random sampling method was applied to obtain the vegetation information of the four types of urban green spaces in Luohe, a common plain city in China; and i-Tree Eco model was further used to assess the vegetation structure and various ecosystem services including air quality improvement, rainfall interception, carbon storage, and sequestration provided by four types of urban green spaces. The modeling results reveal that there were about 1,006,251 trees in this area. In 2013, all the trees in these green spaces could store about 54,329 t of carbon, sequester about 4973 t of gross carbon, remove 92 t of air pollutants, and avoid 122,637 m3 of runoff. The study illustrates an innovative method to reveal different types of urban green spaces with distinct ecosystem service productivity capacity to better understand their various roles in regulating the urban environment. The results could be used to assist urban planners and policymakers to optimize urban green space structure and composition to maximize ecosystem services provision
Structure of FcRY, an avian immunoglobulin receptor related to mammalian mannose receptors, and its complex with IgY
Fc receptors transport maternal antibodies across epithelial cell barriers to passively immunize newborns. FcRY, the functional counterpart of mammalian FcRn (a major histocompatibility complex homolog), transfers IgY across the avian yolk sac, and represents a new class of Fc receptor related to the mammalian mannose receptor family. FcRY and FcRn bind immunoglobulins at pH ≤6.5, but not pH ≥7, allowing receptor–ligand association inside intracellular vesicles and release at the pH of blood. We obtained structures of monomeric and dimeric FcRY and an FcRY–IgY complex and explored FcRY's pH-dependent binding mechanism using electron cryomicroscopy (cryoEM) and small-angle X-ray scattering. The cryoEM structure of FcRY at pH 6 revealed a compact double-ring “head,” in which the N-terminal cysteine-rich and fibronectin II domains were folded back to contact C-type lectin-like domains 1–6, and a “tail” comprising C-type lectin-like domains 7–8. Conformational changes at pH 8 created a more elongated structure that cannot bind IgY. CryoEM reconstruction of FcRY dimers at pH 6 and small-angle X-ray scattering analysis at both pH values confirmed both structures. The cryoEM structure of the FcRY–IgY revealed symmetric binding of two FcRY heads to the dimeric FcY, each head contacting the CH4 domain of one FcY chain. FcRY shares structural properties with mannose receptor family members, including a head and tail domain organization, multimerization that may regulate ligand binding, and pH-dependent conformational changes. Our results facilitate understanding of immune recognition by the structurally related mannose receptor family and comparison of diverse methods of Ig transport across evolution
Effects of different needles and substrates on CuInS2 deposited by electrostatic spray deposition
Copper indium disulphide (CuInS2) thin films were deposited using the electrostatic spray deposition method. The effects of applied voltage and solution flow rate on the aerosol cone shape, film composition, surface morphology and current conversion were investigated. The effect of aluminium substrates and transparent fluorine doped tin oxide (SnO2:F) coated glass substrates on the properties of as-deposited CuInS2 films were analysed. An oxidation process occurs during the deposition onto the metallic substrates which forms an insulating layer between the photoactive film and substrate. The effects of two different spray needles on the properties of the as-deposited films were also studied. The results reveal that the use of a stainless steel needle results in contamination of the film due to the transfer of metal impurities through the spray whilst this is not seen for the glass needle. The films were characterised using a number of different analytical techniques such as X-ray diffraction, scanning electron microscopy, Rutherford back-scattering and secondary ion mass spectroscopy and opto-electronic measurements
Imaging of a patterned and buried molecular layer by coherent acoustic phonon spectroscopy
A molecular layer of aminopropyltriethoxysilane is patterned with a focused ion beam and subsequently covered by a gold film. The gold-polymer-substrate structures are afterwards imaged by ultrafast coherent acoustic phonon spectroscopy in reflection geometry. We demonstrate that the lateral structure of the covered polymer layer can be detected via the damping time of the vibrational mode of the gold film. Furthermore, we utilize Brillouin oscillations originating from the silicon substrate to map the structures and to estimate the molecular layer thickness.Fil: Hettich, Mike . University of Konstanz. Department of Physics and Center for Applied Photonics; AlemaniaFil: Jacob, Karl . University of Konstanz. Department of Physics and Center for Applied Photonics; AlemaniaFil: Ristow, Oliver . University of Konstanz. Department of Physics and Center for Applied Photonics; AlemaniaFil: He, Chuan . University of Konstanz. Department of Physics and Center for Applied Photonics; AlemaniaFil: Mayer, Jan . University of Konstanz. Department of Physics and Center for Applied Photonics; AlemaniaFil: Schubert, Martin . University of Konstanz. Department of Physics and Center for Applied Photonics; AlemaniaFil: Gusev, Vitalyi . Centre National de la Recherche Scientifique; FranciaFil: Bruchhausen, Axel Emerico. University of Konstanz. Department of Physics and Center for Applied Photonics; Alemania. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Area de Investigación y Aplicaciones No Nucleares. Gerencia de Física (Centro Atómico Bariloche); Argentina. Comisión Nacional de Energía Atómica. Gerencia del Area de Energía Nuclear. Instituto Balseiro; ArgentinaFil: Dekorsy, Thomas . University of Konstanz. Department of Physics and Center for Applied Photonics; Alemani
The most plausible explanation of the cyclical period changes in close binaries: the case of the RS CVn-type binary WW Dra
We searched the orbital period changes in 182 EA-type (including the 101
Algol systems used by \cite{hal89}), 43 EB-type and 53 EW-type binaries with
known both the mass ratio and the spectral type of their secondary components.
We reproduced and improved the same diagram as Hall's (1989) according to the
new collected data. Our plots do not support the conclusion derived by
\cite{hal89} that all cases of cyclical period changes are restricted to
binaries having the secondary component with spectral types later than F5. The
presence of period changes also among stars with secondary component of early
type indicates that the magnetic activity is one cause, but not the only one,
for the period variation. It is discovered that cyclic period changes, likely
due to the presence of a third body are more frequent in EW-type binaries among
close binaries. Therefore, the most plausible explanation of the cyclical
period changes is the LTTE via the presence of a third body. By using the
century-long historical record of the times of light minimum, we analyzed the
cyclical period change in the Algol binary WW Dra. It is found that the orbital
period of the binary shows a cyclic variation
with an amplitude of . The cyclic oscillation
can be attributed to the LTTE via a third body with a mass no less than . However, no spectral lines of the third body were discovered
indicating that it may be a candidate black hole. The third body is orbiting
the binary at a distance shorter than 14.4 AU and it may play an important role
in the evolution of this system.Comment: 9 pages, 5 figures, published by MNRA
Searching for TeV dark matter by atmospheric Cerenkov techniques
There is a growing interest in the possibility that dark matter could be
formed of weakly interacting particles with a mass in the 100 GeV - 2 TeV
range, and supersymmetric particles are favorite candidates. If they constitute
the dark halo of our Galaxy, their mutual annihilations produce energetic gamma
rays that could be detected using existing atmospheric \u{C}erenkov techniques.Comment: 10 pp, LaTex (3 figures available by e-mail) PAR-LPTHE 92X
Development and Optimization of Chromosomally-Integrated Fluorescent <i>Mycobacterium tuberculosis</i> Reporter Constructs
Cyclic dermal BMP signalling regulates stem cell activation during hair regeneration
In the age of stem cell engineering it is critical to understand how stem cell activity is regulated during regeneration. Hairs are mini-organs that undergo cyclic regeneration throughout adult life1, and are an important model for organ regeneration. Hair stem cells located in the follicle bulge2 are regulated by the surrounding microenvironment, or niche3. The activation of such stem cells is cyclic, involving periodic -catenin activity4, 5, 6, 7. In the adult mouse, regeneration occurs in waves in a follicle population, implying coordination among adjacent follicles and the extrafollicular environment. Here we show that unexpected periodic expression of bone morphogenetic protein 2 (Bmp2) and Bmp4 in the dermis regulates this process. This BMP cycle is out of phase with the WNT/-catenin cycle, thus dividing the conventional telogen into new functional phases: one refractory and the other competent for hair regeneration, characterized by high and low BMP signalling, respectively. Overexpression of noggin, a BMP antagonist, in mouse skin resulted in a markedly shortened refractory phase and faster propagation of the regenerative wave. Transplantation of skin from this mutant onto a wild-type host showed that follicles in donor and host can affect their cycling behaviours mutually, with the outcome depending on the equilibrium of BMP activity in the dermis. Administration of BMP4 protein caused the competent region to become refractory. These results show that BMPs may be the long-sought 'chalone' inhibitors of hair growth postulated by classical experiments. Taken together, results presented in this study provide an example of hierarchical regulation of local organ stem cell homeostasis by the inter-organ macroenvironment. The expression of Bmp2 in subcutaneous adipocytes indicates physiological integration between these two thermo-regulatory organs. Our findings have practical importance for studies using mouse skin as a model for carcinogenesis, intra-cutaneous drug delivery and stem cell engineering studies, because they highlight the acute need to differentiate supportive versus inhibitory regions in the host skin
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