1,305 research outputs found
High-Vacuum Condenser Design: Experimental Effects from Cesium and Mercury Ion Beams
Effects of variable-energy electrostatic rocket-engine ion exhaust beams that pertain to the design of high-vacuum condensers are discussed. Three ion-engine beam sources, using cesium and mercury as propellants, were operated at energy levels of 200 to 9000 electron volts and currents of 0.002 to 0.200 ampere. Five condenser geometries, having surface areas from 0.287 to 5.76 square meters, were tested. Values for a function of the accommodation and condensation coefficients, which appears in an existing theoretical analysis, were determined. Although exhibiting rather wide variations in some tests, the values were estimated at approximately 0.15 for cesium and 0.015 for mercury. A method of estimating condenser surface area requirements is given
identification of peri prostatic neurovascular fibers before and after radical prostatectomy by means of diffusion tensor imaging dti with clinical correlations initial experience
Aim: To evaluate if Diffusion Tensor Imaging (DTI) is able to detect morphological changes of peri-prostatic neurovascular fibers (PNF) before and after robot-assisted radical prostatectomy (RARP) and if these changes are related to urinary incontinence (UI) and erectile dysfunction (ED).
Materials and methods: From October 2014 and August 2017 26 patients with biopsy-proven prostate cancer underwent prostatic multi-parametric magnetic resonance imaging (mp-MRI) including DTI sequencing before and six months after, RARP. Images were analyzed by placing six regions of interest (ROI) respectively at the base, mid-gland and apex, one for each side, to obtain tractography reconstruction of the PNF. Patients were asked to complete an International Consultation Incontinence Questionnaire – Short Form (ICIQ-SF) and International Index of Erectile Function (IIEF-5) questionnaires before RARP and 6 months postoperatively. Fractional anisotropy (FA), number (N) and length (L) of PNF before and after RARP were compared by means of Student's t-test; Spearman test was used to evaluate the correlation between DTI parameters and questionnaires scores. We observed a significant difference in N values before and after RARP (p<0.001) and a negative correlation between IIEF-5 score and post-operative FA values at both the right (rho=-0.42; p= 0.0456) and left (rho=- 0.66; p=0.0006) base of the prostate. DTI with tractography of PNF is able to detect quantitative changes in N, L and FA values in PNF after RARP. In particular we observed an inverse correlation between FA of PNF and ED at 6 months after RARP. Further investigations are needed to confirm this trend
A risk of breast cancer in women - carriers of constitutional CHEK2 gene mutations, originating from the North - Central Poland
I just did it for the kids: mothering in the context of living with an increased risk of ovarian cancer
Complete IRAC mapping of the CFHTLS-DEEP, MUSYC AND NMBS-II FIELDS
The IRAC mapping of the NMBS-II fields program is an imaging survey at 3.6
and 4.5m with the Spitzer Infrared Array Camera (IRAC). The observations
cover three Canada-France-Hawaii Telescope Legacy Survey Deep (CFHTLS-D)
fields, including one also imaged by AEGIS, and two MUSYC fields. These are
then combined with archival data from all previous programs into deep mosaics.
The resulting imaging covers a combined area of about 3 , with at least
2 hr integration time for each field. In this work, we present our data
reduction techniques and document the resulting coverage maps at 3.6 and
4.5m. All of the images are W-registered to the reference image, which is
either the z-band stack image of the 25\% best seeing images from the CFHTLS-D
for CFHTLS-D1, CFHTLS-D3, and CFHTLS-D4, or the K-band images obtained at the
Blanco 4-m telescope at CTIO for MUSYC1030 and MUSYC1255. We make all images
and coverage maps described herein publicly available via the Spitzer Science
Center.Comment: Accepted in PASP; released IRAC mosaics available upon publication of
the pape
Molecular vibration in cold collision theory
Cold collisions of ground state oxygen molecules with Helium have been
investigated in a wide range of cold collision energies (from 1 K up to 10
K) treating the oxygen molecule first as a rigid rotor and then introducing the
vibrational degree of freedom. The comparison between the two models shows that
at low energies the rigid rotor approximation is very accurate and able to
describe all the dynamical features of the system. The comparison between the
two models has also been extended to cases where the interaction potential He -
O is made artificially stronger. In this case vibration can perturb rate
constants, but fine-tuning the rigid rotor potential can alleviate the
discrepancies between the two models.Comment: 11 pages, 3 figure
Entropic Uncertainty Relations in Quantum Physics
Uncertainty relations have become the trademark of quantum theory since they
were formulated by Bohr and Heisenberg. This review covers various
generalizations and extensions of the uncertainty relations in quantum theory
that involve the R\'enyi and the Shannon entropies. The advantages of these
entropic uncertainty relations are pointed out and their more direct connection
to the observed phenomena is emphasized. Several remaining open problems are
mentionedComment: 35 pages, review pape
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