5,409 research outputs found
Solar energy water desalination in the United States and Saudi Arabia
Five solar energy water desalination systems were designed to deliver 6000 cubic m/day of desalted water from either seawater or brackish water. Two systems will be selected for pilot plant construction. The pilot plants will have capacities in the range of 100 to 400 m/day. Goals of the Project Agreement for Cooperation in the Field of Solar Energy, under the auspices of the United States-Saudi Arabian Joint Commission on Economic Cooperation, are to: (1) cooperate in the field of solar energy technology for the mutual benefit of the two countries, including the development and stimulation of solar industries within the two countries; (2) advance the development of solar energy technology in the two countries; and (3) facilitate the transfer between the two countries of technology developed under this agreement
Quantizations on the circle and coherent states
We present a possible construction of coherent states on the unit circle as
configuration space. Our approach is based on Borel quantizations on S^1
including the Aharonov-Bohm type quantum description. The coherent states are
constructed by Perelomov's method as group related coherent states generated by
Weyl operators on the quantum phase space Z x S^1. Because of the duality of
canonical coordinates and momenta, i.e. the angular variable and the integers,
this formulation can also be interpreted as coherent states over an infinite
periodic chain. For the construction we use the analogy with our quantization
and coherent states over a finite periodic chain where the quantum phase space
was Z_M x Z_M. The coherent states constructed in this work are shown to
satisfy the resolution of unity. To compare them with canonical coherent
states, also some of their further properties are studied demonstrating
similarities as well as substantial differences.Comment: 15 pages, 4 figures, accepted in J. Phys. A: Math. Theor. 45 (2012)
for the Special issue on coherent states: mathematical and physical aspect
Specialized physiological studies in support of manned space flight
The effects of a diuretic (Lasix) induced dehydration on the cardiovascular and hematological responses to lower body negative pressure (LBNP) were analyzed and compared to previous observations on dehydration following exercise in the heat. During LBNP runs the subjects were monitored for changes in blood volume, heart rate, blood pressure, and variations in the volume of the left calf. It was concluded that Lasix dehydration produced a depletion of the body electrolytes at the expense of both the plasma and extravascular compartments. Striking differences were found between those subjects who were physically active (Runners: R) and those who did not engage in any regular physical activity (Non-runners: NR). Tolerance to LBNP (Torr x min) was significantly lower in the R's than the NR's before and after dehydration, however the R's lost more of their tolerance after dehydration with Lasix than after exercise in the heat for about the same fluid loss. The opposite was true for the NR's. Two factors appear to be responsible for the lower LBNP tolerance in R's: parasympathetic inhibition of cardiac activity during LBNP and a greater propensity to pool blood in the lower extremities
Coherent states on the circle
We present a possible construction of coherent states on the unit circle as
configuration space. In our approach the phase space is the product Z x S^1.
Because of the duality of canonical coordinates and momenta, i.e. the angular
variable and the integers, this formulation can also be interpreted as coherent
states over an infinite periodic chain. For the construction we use the analogy
with our quantization over a finite periodic chain where the phase space was
Z_M x Z_M. Properties of the coherent states constructed in this way are
studied and the coherent states are shown to satisfy the resolution of unity.Comment: 7 pages, presented at GROUP28 - "28th International Colloquium on
Group Theoretical Methods in Physics", Newcastle upon Tyne, July 2010.
Accepted in Journal of Physics Conference Serie
Erdheim-Chester disease and knee pain in a dialysis patient
Erdheim–Chester disease is a rare inflammatory condition characterized by a non-Langerhans histiocytic infiltration, involving the skeleton, nervous system, viscera, retroperitoneum and elsewhere. The aetiology is unknown. Positron emission tomography shows areas of involvement. We managed a dialysis patient with knee pain; a bone marrow specimen showed typical CD68 positive, but CD1a negative cells. We initiated interferon-α therapy although other options remain open. In our patient, the simultaneous presence of secondary hyperparathyroidism with tumorous calcifications provided an interesting additional differential diagnostic possibility regarding skeletal pain
Dihedral symmetry of periodic chain: quantization and coherent states
Our previous work on quantum kinematics and coherent states over finite
configuration spaces is extended: the configuration space is, as before, the
cyclic group Z_n of arbitrary order n=2,3,..., but a larger group - the
non-Abelian dihedral group D_n - is taken as its symmetry group. The
corresponding group related coherent states are constructed and their
overcompleteness proved. Our approach based on geometric symmetry can be used
as a kinematic framework for matrix methods in quantum chemistry of ring
molecules.Comment: 13 pages; minor changes of the tex
Targeting kidney mesangium by nanoparticles of defined size
Nanoparticles are being investigated for numerous medical applications and are showing potential as an emerging class of carriers for drug delivery. Investigations on how the physicochemical properties (e.g., size, surface charge, shape, and density of targeting ligands) of nanoparticles enable their ability to overcome biological barriers and reach designated cellular destinations in sufficient amounts to elicit biological efficacy are of interest. Despite proven success in nanoparticle accumulation at cellular locations and occurrence of downstream therapeutic effects (e.g., target gene inhibition) in a selected few organs such as tumor and liver, reports on effective delivery of engineered nanoparticles to other organs still remain scarce. Here, we show that nanoparticles of ~75 ± 25-nm diameters target the mesangium of the kidney. These data show the effects of particle diameter on targeting the mesangium of the kidney. Because many diseases originate from this area of the kidney, our findings establish design criteria for constructing nanoparticle-based therapeutics for targeting diseases that involve the mesangium of the kidney
Inhibition of Trophoblast-Induced Spiral Artery Remodeling Reduces Placental Perfusion in Rat Pregnancy.
Rats harboring the human angiotensinogen and human renin genes develop preeclamptic features in pregnancy. The preeclamptic rats exhibit a deeper trophoblast invasion associated with a reduced resistance index by uterine
Doppler. Doxycycline inhibits matrix metalloproteinase activity. We tested the hypothesis that matrix metalloproteinase inhibition reduces trophoblast invasion with subsequent changes in placental perfusion. Preeclamptic and pregnant control Sprague-Dawley rats were treated with doxycycline (30 mg/kg of body weight orally) from gestational day 12 until day 18. Placental perfusion was assessed using a micromarker contrast agent. The animals were euthanized on day 18 of pregnancy; biometric data were acquired, and trophoblast invasion was analyzed. Doxycycline resulted in intrauterine growth retardation and lighter placentas in both groups. Maternal body weight was not affected. As shown earlier, preeclamptic rats exhibited a deeper endovascular trophoblast invasion. However, doxycycline treatment reduced trophoblast invasion in the preeclamptic rats. The physiological spiral artery remodeling, as assessed by the deposition of fibrinoid and α-actin in the spiral artery contour, was significantly reduced by doxycycline. The vascularity index, as assessed by perfusion measurement of the placenta, was reduced after doxycycline treatment in preeclamptic rats. Thus, matrix metalloproteinase inhibition with doxycycline leads to reduced trophoblast invasion and associated reduced placental perfusion. These studies are the first to show that reducing trophoblast-induced vascular remodeling decreases subsequent placental perfusion. Our model allows the study of dysregulated trophoblast invasion and vascular remodeling in vivo to gain important insights into preeclampsia-related mechanisms
Proactive Management in Academic Libraries: Promoting Improved Communication and Inclusion of Academic Librarians and Archivists in Cybersecurity Policy Creation
Although increasing cybersecurity threats continue in libraries, not many studies are available which examine surrounding cybersecurity policies. Even less has been done on specific types of libraries such as academic and archives. When it comes to academic libraries, cybersecurity policies take a top-down approach to managing and creating policies. The problem is that both academic libraries and archives are unique areas within a university setting. Some of the general policies do not always handle specific issues dealt with in an academic library or archives. This paper investigates if an actual gap or void in policy exists which could create issues in academic libraries and archives, as well as if the university cybersecurity policy is being communicated, reviewed, reported, and created with inclusion of librarians and archivists. An 18-question survey was administered to librarians, archivists, and university information technology cybersecurity professionals within the 24 academic institutions of University Systems of Georgia (USG). Twenty-seven respondents completed the survey. The survey was, then, analyzed according to subcategories. A general theme emerged: communication of cybersecurity policy and the inclusion of librarians and archivists in policy creation and reporting could improve cybersecurity defense. The lack of participation and report feedback also lead to a very low perception or barometer score (5.1 average on a 10-point scale) as to how well the cybersecurity plan was being communicated. The solution to the communication gap could be in form of a plan. A conceptual model entitled Communication Enlightenment Engagement Plan (CEEP) would increase involvement by community engagement (inclusion, policy review, and policy creation.) Adding a feedback loop to CEEP will aid in the engagement process as well as keeping top tiers of management aware of policy changes and issues
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