188 research outputs found
Automatic focus control for facsimile cameras
An electronic circuit for controlling the focus of facsimile cameras is described. The circuit consists of balanced a.c. amplifiers, two square law function generators, and a differential amplifier and power drive. The invention includes a method for maintaining the imaging sensor at the expected location of the focal plane as the facsimile camera scans a scene or terrain. A block diagram of the electronic circuitry is provided
Laser communication system for controlling several functions at a location remote to the laser
A multichannel laser remote control system is described. The system is used in areas where radio frequency, acoustic, and hardware control systems are unsatisfactory or prohibited and where line of sight is unobstructed. A modulated continuous wave helium-neon laser is used as the transmitter and a 360 degree light collector serves as the antenna at the receiver
Key Ne states identified affecting -ray emission from F in novae
Detection of nuclear-decay rays provides a sensitive thermometer of
nova nucleosynthesis. The most intense -ray flux is thought to be
annihilation radiation from the decay of F, which is destroyed
prior to decay by the F(,)O reaction. Estimates of
F production had been uncertain, however, because key near-threshold
levels in the compound nucleus, Ne, had yet to be identified. This
Letter reports the first measurement of the
F(He,)Ne reaction, in which the placement of two
long-sought 3/2 levels is suggested via triton--
coincidences. The precise determination of their resonance energies reduces the
upper limit of the rate by a factor of at nova temperatures and
reduces the average uncertainty on the nova detection probability by a factor
of 2.1.Comment: 6 pages, 4 figure
New -ray Transitions Observed in Ne with Implications for the O(,)Ne Reaction Rate
The O(,)Ne reaction is responsible for breakout
from the hot CNO cycle in Type I x-ray bursts. Understanding the properties of
resonances between and 5 MeV in Ne is crucial in the
calculation of this reaction rate. The spins and parities of these states are
well known, with the exception of the 4.14- and 4.20-MeV states, which have
adopted spin-parities of 9/2 and 7/2, respectively. Gamma-ray
transitions from these states were studied using triton--
coincidences from the F(He,)Ne reaction measured
with GODDESS (Gammasphere ORRUBA Dual Detectors for Experimental Structure
Studies) at Argonne National Laboratory. The observed transitions from the
4.14- and 4.20-MeV states provide strong evidence that the values are
actually 7/2 and 9/2, respectively. These assignments are consistent
with the values in the F mirror nucleus and in contrast to previously
accepted assignments
Development of the (d,n) proton-transfer reaction in inverse kinematics for structure studies
Transfer reactions have provided exciting opportunities to study the
structure of exotic nuclei and are often used to inform studies relating to
nucleosynthesis and applications. In order to benefit from these reactions and
their application to rare ion beams (RIBs) it is necessary to develop the tools
and techniques to perform and analyze the data from reactions performed in
inverse kinematics, that is with targets of light nuclei and heavier beams. We
are continuing to expand the transfer reaction toolbox in preparation for the
next generation of facilities, such as the Facility for Rare Ion Beams (FRIB),
which is scheduled for completion in 2022. An important step in this process is
to perform the (d,n) reaction in inverse kinematics, with analyses that include
Q-value spectra and differential cross sections. In this way, proton-transfer
reactions can be placed on the same level as the more commonly used
neutron-transfer reactions, such as (d,p), (9Be,8Be), and (13C,12C). Here we
present an overview of the techniques used in (d,p) and (d,n), and some recent
data from (d,n) reactions in inverse kinematics using stable beams of 12C and
16O.Comment: 9 pages, 4 figures, presented at the XXXV Mazurian Lakes Conference
on Physics, Piaski, Polan
Surface accuracy measurement sensor test on a 50-meter antenna surface model
The Surface Accuracy Measurement Sensor (SAMS) is a telescope with a focal plane photo electric detector that senses the lateral position of light source targets in its field of view. After extensive laboratory testing the engineering breadboard sensor system was installed and tested on a 30 degree segment of a 50-meter diameter, mesh surface, antenna model. Test results correlated well with the laboratory tests and indicated accuracies of approximately 0.59 arc seconds at 21 meters range. Test results are presented and recommendations given for sensor improvements
Gender-differences of in vitro colonic motility after chemo- and radiotherapy in humans.
Background: The aim of the present in vitro study was to investigate, in different genders, motor responses in surgical colonic specimens from patients with rectal cancer undergoing and not undergoing chemotherapy with capecitabine and radiotherapy.
Methods: This in vitro study was conducted from October 2015 to August 2017 at the Experimental Pharmacology Laboratory at the National Institute “S. de Bellis” after collecting samples at the Department of Surgery. Segments of sigmoid colon were obtained from 15 patients (Male (M)/Female (F) = 8/7; control group, CG) operated on for elective colorectal resection for rectal cancer without obstruction and 14 patients (M/F = 7/7; study group, SG) operated on for elective colorectal resection for rectal cancer who also received chemotherapy, based on capecitabine twice daily, and radiotherapy. Isometric tension was measured on colonic circular muscle strips exposed to increasing carbachol or histamine concentrations to obtain concentration-response curves. The motor responses to electrically evoked
stimulation were also investigated.
Results: In males, carbachol and histamine caused concentration-dependent contractions in the CG and SG. An increased sensitivity and a higher response to carbachol and histamine were observed in SG than CG (P < 0.01). On the contrary, in females, the response to carbachol was not significantly different in CG from the SG and the maximal responses to carbachol were greater in CG than in SG (P < 0.001). The same applied to histamine for half-maximal effective concentrations and maximal response in that they were not significantly different in CG from the SG. Electrically evoked contractions were significantly more pronounced in males, especially in the SG (P < 0.05).
Conclusions: This preliminary in vitro study has shown gender differences in motor responses of colonic circular muscle strips in patients who had received chemotherapy with capecitabine and radiotherapy
The battle over Syria's reconstruction
Reconstruction is becoming the new battleground in the Syrian conflict—its continuation by other means. It is instrumentalized by the regime as a way to reconsolidate its control over the country and by rival regional and international powers to shape the internal balance of power and establish spheres of influence in the country. The paper examines the Asad regime’s practices, including co-optation of militia leaders via reconstruction concessions and use of reconstruction to clear strategic areas of opposition-dominated urban settlements. The paper then surveys how the geopolitical struggle in Syria has produced an asymmetry as regards reconstruction: those powers that lost the geo-political contest on the ground seek to use geo-economic superiority to reverse the geo-political outcome. Then the impact of proxy wars and spheres of influence in the country on the security context for reconstruction is examined. Finally, the reconstruction initiatives of the various external parties are assessed, including Russia, Iran and Turkey as well as the spoiler role by which the US seeks to obstruct reconstruction that would spell victory in Syria for its Russian and Iranian rivals.PostprintPeer reviewe
Direct Reaction Measurements Using GODDESS
GODDESS is a coupling of the charged-particle detection system ORRUBA to the gamma-ray detector array Gammasphere. This coupling has been developed in order to facilitate the high-resolution measurement of direct reactions in normal and inverse kinematics with stable and radioactive beams. GODDESS has been commissioned using a beam of 134Xe at 10 MeV/A, in a campaign of stable beam measurements. The measurement demonstrates the capabilities of GODDESS under radioactive beam conditions, and provides the first data on the single-neutron states in 135Xe, including previously unobserved states based on the orbitals above the N=82 shell closure
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