3,145 research outputs found
Development of EM-CCD-based X-ray detector for synchrotron applications
A high speed, low noise camera system for crystallography and X-ray imaging applications is developed and successfully demonstrated. By coupling an electron-multiplying (EM)-CCD to a 3:1 fibre-optic taper and a CsI(Tl) scintillator, it was possible to detect hard X-rays. This novel approach to hard X-ray imaging takes advantage of sub-electron equivalent readout noise performance at high pixel readout frequencies of EM-CCD detectors with the increase in the imaging area that is offered through the use of a fibre-optic taper. Compared with the industry state of the art, based on CCD camera systems, a high frame rate for a full-frame readout (50 ms) and a lower readout noise (<1 electron root mean square) across a range of X-ray energies (6–18 keV) were achieved
Investigation of objective functions and operation rules for storage reservoirs
Submitted to Office of Water Research and Technology.September 1981.Bibliography: pages 31-32.OWRT project no. B-195-COLO
Surface Irrigation Systems
In surface irrigation, water is conveyed to the point of infiltration directly on
the soil surface. Thus, the soil surface may be considered as the conveyance
channel boundary. Surface irrigation channels vary widely in shape, size, and
hydraulic characteristics
Cool White Dwarfs Identified in the Second Data Release of the UKIRT Infrared Deep Sky Survey
We have paired the Second Data Release of the Large Area Survey of the UKIRT
Infrared Deep Sky Survey with the Fifth Data Release of the Sloan Digital Sky
Survey to identify ten cool white dwarf candidates, from their photometry and
astrometry. Of these ten, one was previously known to be a very cool white
dwarf. We have obtained optical spectroscopy for seven of the candidates using
the GMOS-N spectrograph on Gemini North, and have confirmed all seven as white
dwarfs. Our photometry and astrometry indicates that the remaining two objects
are also white dwarfs. Model analysis of the photometry and available
spectroscopy shows that the seven confirmed new white dwarfs, and the two new
likely white dwarfs, have effective temperatures in the range Teff = 5400-6600
K. Our analysis of the previously known white dwarf confirms that it is cool,
with Teff = 3800 K. The cooling age for this dwarf is 8.7 Gyr, while that of
the nine ~6000 K white dwarfs is 1.8-3.6 Gyr. We are unable to determine the
masses of the white dwarfs from the existing data, and therefore we cannot
constrain the total ages of the white dwarfs. The large cooling age for the
coolest white dwarf in the sample, combined with its low estimated tangential
velocity, suggests that it is an old member of the thin disk, or a member of
the thick disk of the Galaxy, with an age 10-11 Gyr. The warmer white dwarfs
appear to have velocities typical of the thick disk or even halo; these may be
very old remnants of low-mass stars, or they may be relatively young thin disk
objects with unusually high space motion.Comment: 37 pages (referee format), 4 tables, 7 figures, accepted to Ap
Investigating MgII Absorption in Paired Quasar Sight-Lines
We test whether the Tinker & Chen model of MgII absorption due to the gaseous
halo around a galaxy can reproduce absorption in quasar pairs (both lensed and
physical) and lensed triples and quads from the literature. These quasars
exhibit absorption from a total of 38 MgII systems spanning z=0.043 - 2.066
with mean redshift =1.099 and weighted mean rest-frame equivalent width of
0.87 Ang. Using the Tinker & Chen model to generate simulated sight-lines, we
marginalize the unknown parameters of the absorbing galaxies: dark matter halo
mass, impact parameter, and azimuthal angle on the sky. We determine the
ability of the model to statistically reproduce the observed variation in MgII
absorption strength between paired sight-lines for different values of the gas
covering fraction f_c and the characteristic length scale ell_c, within which
the variation in absorption equivalent widths between sight-lines exponentially
decreases. We find a best-fit f_c=0.60 \pm 0.15 and ell_c<8/h_70 kpc (1\sigma
confidence limits), with smaller f_c allowed at larger ell_c. At 99.7%
confidence, we are able to rule out f_c>0.87 for all values of ell_c and the
region where ell_c<1.0/h_70 kpc and f_c<0.3.Comment: 24 pages, 11 figures, 2 tables, accepted for publication in MNRAS, 1
Dec 201
Crystal structures of three functionalized chalcones:4'-di-methyl-amino-3-nitro-chalcone, 3-di-methyl-amino-3'-nitrochalcone and 3'-nitro-chalcone
Protocol for hypofractionated adaptive radiotherapy to the bladder within a multicentre phase II randomised trial: radiotherapy planning and delivery guidance.
INTRODUCTION:Patients with muscle invasive bladder cancer (MIBC) who are unfit and unsuitable for standard radical treatment with cystectomy or daily radiotherapy present a large unmet clinical need. Untreated, they suffer high cancer specific mortality and risk significant disease-related local symptoms. Hypofractionated radiotherapy (delivering higher doses in fewer fractions/visits) is a potential treatment solution but could be compromised by the mobile nature of the bladder, resulting in target misses in a significant proportion of fractions. Adaptive 'plan of the day' image-guided radiotherapy delivery may improve the precision and accuracy of treatment. We aim to demonstrate within a randomised multicentre phase II trial feasibility of plan of the day hypofractionated bladder radiotherapy delivery with acceptable rates of toxicity. METHODS AND ANALYSIS:Patients with T2-T4aN0M0 MIBC receiving 36 Gy in 6-weekly fractions are randomised (1:1) between treatment delivered using a single-standard plan or adaptive radiotherapy using a library of three plans (small, medium and large). A cone beam CT taken prior to each treatment is used to visualise the anatomy and select the most appropriate plan depending on the bladder shape and size. A comprehensive radiotherapy quality assurance programme has been instituted to ensure standardisation of radiotherapy planning and delivery. The primary endpoint is to exclude >30% acute grade >3 non-genitourinary toxicity at 3 months for adaptive radiotherapy in patients who received >1 fraction (p0=0.7, p1=0.9, α=0.05, β=0.2). Secondary endpoints include local disease control, symptom control, late toxicity, overall survival, patient-reported outcomes and proportion of fractions benefiting from adaptive planning. Target recruitment is 62 patients. ETHICS AND DISSEMINATION:The trial is approved by the London-Surrey Borders Research Ethics Committee (13/LO/1350). The results will be disseminated via peer-reviewed scientific journals, conference presentations and submission to regulatory authorities. TRIAL REGISTRATION NUMBER:NCT01810757
Identification of actin nucleation activity and polymerization inhibitor in ameboid cells: their regulation by chemotactic stimulation.
Pitch Processing Sites in the Human Auditory Brain
Lateral Heschl's gyrus (HG), a subdivision of the human auditory cortex, is commonly believed to represent a general “pitch center,” responding selectively to the pitch of sounds, irrespective of their spectral characteristics. However, most neuroimaging investigations have used only one specialized pitch-evoking stimulus: iterated-ripple noise (IRN). The present study used a novel experimental design in which a range of different pitch-evoking stimuli were presented to the same listeners. Pitch sites were identified by searching for voxels that responded well to the range of pitch-evoking stimuli. The first result suggested that parts of the planum temporale are more relevant for pitch processing than lateral HG. In some listeners, pitch responses occurred elsewhere, such as the temporo-parieto-occipital junction or prefrontal cortex. The second result demonstrated a different pattern of response to the IRN and raises the possibility that features of IRN unrelated to pitch might contribute to the earlier results. In conclusion, it seems premature to assign special status to lateral HG solely on the basis of neuroactivation patterns. Further work should consider the functional roles of these multiple pitch processing sites within the proposed network
Crystal structure and Hirshfeld analysis of 3'-bromo-4-methylchalcone and 3'-cyano-4- methylchalcone
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