8,921 research outputs found
Pattern recognition receptors in antifungal immunity
We thank the Wellcome Trust for funding this study.Peer reviewedPublisher PD
Mollusca of the Illinois River, Arkansas
The Illinois River is in the Ozark region of northwestern Arkansas and eastern Oklahoma. A survey of the Illinois River in Arkansas produced nine species and one morphological subspecies of gastropods, three species of sphaeriid clams, and 23 species of unionid mussels. Museum records resulted in another two species and an ecophenotype of the Unionidae. This represents the first published survey of molluscan species from the Illinois River in Arkansas
Electron-Electron Bremsstrahlung Emission and the Inference of Electron Flux Spectra in Solar Flares
Although both electron-ion and electron-electron bremsstrahlung contribute to
the hard X-ray emission from solar flares, the latter is normally ignored. Such
an omission is not justified at electron (and photon) energies above
keV, and inclusion of the additional electron-electron bremsstrahlung in
general makes the electron spectrum required to produce a given hard X-ray
spectrum steeper at high energies.
Unlike electron-ion bremsstrahlung, electron-electron bremsstrahlung cannot
produce photons of all energies up to the maximum electron energy involved. The
maximum possible photon energy depends on the angle between the direction of
the emitting electron and the emitted photon, and this suggests a diagnostic
for an upper cutoff energy and/or for the degree of beaming of the accelerated
electrons.
We analyze the large event of January 17, 2005 observed by RHESSI and show
that the upward break around 400 keV in the observed hard X-ray spectrum is
naturally accounted for by the inclusion of electron-electron bremsstrahlung.
Indeed, the mean source electron spectrum recovered through a regularized
inversion of the hard X-ray spectrum, using a cross-section that includes both
electron-ion and electron-electron terms, has a relatively constant spectral
index over the range from electron kinetic energy keV to MeV. However, the level of detail discernible in the recovered electron
spectrum is not sufficient to determine whether or not any upper cutoff energy
exists.Comment: 7 pages, 5 figures, submitted to Astrophysical Journa
Submitted to Geochimica et Cosmochimica Acta
FTIR and EXAFS spectroscopic measurements were performed on Pb(II)EDTA adsorbed on goethite as functions of pH (4-6), Pb(II)EDTA concentration (0.11 ĀµM- 72 ĀµM), and ionic strength (16 ĀµM- 0.5M). FTIR measurements show no evidence for carboxylate-Fe(III) bonding or protonation of EDTA at Pb:EDTA = 1:1. Both FTIR and EXAFS measurements suggest that EDTA acts as a hexadentate ligand, with all four of its carboxylate and both amine groups bonded to Pb(II). No evidence was observed for inner-sphere Pb(II)-goethite bonding at Pb:EDTA = 1:1. Hence, the adsorbed complexes should have composition Pb(II)EDTA 2-. Since substantial uptake of PbEDTA(II) 2- occurred in the samples, we infer that Pb(II)EDTA 2- adsorbed as outer-sphere complexes and/or as complexes that lose part of their solvation shells and hydrogen bond directly to goethite surface sites. We propose the term āhydration-sphere ā for the latter type of complexes because they should occupy space in the primary hydration spheres of goethite surface functional groups, and to distinguish this mode of sorption from common structural definitions of inner- and outer-sphere complexes. The similarity of Pb(II) uptake isotherms to those of other divalent metal ions complexed by EDTA suggests that they too adsorb by these mechanisms. The lack of evidence for inner-sphere EDTA-Fe(III) bonding suggests that previously proposed metal-ligand- promoted dissolution mechanisms should be modified, specifically to account for the presence of outer-sphere precursor species
Duration judgements in patients with schizophrenia
Background. The ability to encode time cues underlies many cognitive processes. In the light of schizophrenic patients' compromised cognitive abilities in a variety of domains, it is noteworthy that there are numerous reports of these patients displaying impaired timing abilities. However, the timing intervals that patients have been evaluated on in prior studies vary considerably in magnitude (e.g. 1 s, 1 min, 1 h etc.).
Method. In order to obviate differences in abilities in chronometric counting and place minimal demands on cognitive processing, we chose tasks that involve making judgements about brief durations of time (<1 s).
Results. On a temporal generalization task, patients were less accurate than controls at recognizing a standard duration. The performance of patients was also significantly different from controls on a temporal bisection task, in which participants categorized durations as short or long. Although time estimation may be closely intertwined with working memory, patients' working memory as measured by the digit span task did not correlate significantly with their performance on the duration judgement tasks. Moreover, lowered intelligence scores could not completely account for the findings.
Conclusions. We take these results to suggest that patients with schizophrenia are less accurate at estimating brief time periods. These deficits may reflect dysfunction of biopsychological timing processes
Preparing CySat-1: A look at Iowa State Universityās first CubeSat
In this paper, an overview of the scientific mission of CySat-1, the derived vehicle requirements, impact on system design, and the educational opportunities presented by these challenges. CySat-1, previously scheduled for launch on the SpaceX-21 and awaiting further details following the COVID-19 pandemic, is a CubeSat designed and built by students at Iowa State University. The primary mission of CySat-1 is to provide hands-on experience to undergraduate students in designing, building, and testing a space system. CySat-1 also hosts a scientific payload, a software-defined radio (SDR) radiometer, to survey soil moisture content on Earth from Low Earth Orbit. This mission further reinforces the affordability of CubeSats for future research missions. The Iowa State University CubeSat, CySat-1, was selected for NASAās CubeSat launch initiative (CSLI) program and will be launched with a future ELaNa mission. The operation will be for three to six months after the deployment from the International Space Station.
We will discuss the overall function of the payload and how we integrated the payload into the CubeSat. This discussion will include the student-initiative design and fabrication of critical components, including the payload and CubeSat structures. CySat-1 augments in-house, student designs with commercial off-the-shelf (COTS) components, creating a real-world integration challenge. Iowa State Universityās first CubeSat program spurred the installation of facilities such as a clean room with the anti-static capability to support building, testing, and integration of delicate space hardware. Through this process, students acquired experience with industrial level integration and testing procedures.
Undergraduate teams working on CySat-1 lead the design and fabrication of the payload, structure, and system integration, providing experience with systems engineering, technical writing, and various cross-disciplinary applications. Over sixty undergraduate students, several graduate students, and four faculty members from multiple departments worked on the development of this CubeSat under the Make to Innovate program at Iowa State University, which engages students in various projects to augment their understanding of engineering fundamentals
Candida albicans Hypha Formation and Mannan Masking of Ī²-Glucan Inhibit Macrophage Phagosome Maturation
Received 28 August 2014 Accepted 28 October 2014 Published 2 December 2014 This is an open-access article distributed under the terms of the Creative Commons Attribution 3.0 Unported license. ACKNOWLEDGMENTS We thank Janet Willment, Aberdeen Fungal Group, University of Aberdeen, for kindly providing the soluble Dectin-1-Fc reporter. All microscopy was performed with the assistance of the University of Aberdeen Core Microscopy & Histology Facility, and we thank the IFCC for their assistance with flow cytometry. We thank the Wellcome Trust for funding (080088, 086827, 075470, 099215, 097377, and 101873). E.R.B. and A.J.P.B. are funded by the European Research Council (ERC-2009-AdG-249793), and J.L. is funded by a Medical Research Council Clinical Training Fellowship.Peer reviewedPublisher PD
Microwave Gaseous Discharges
Contains reports on four research projects.Atomic Energy Commission under Contract AT(30-1)-184
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