New Models for UO2 Fuel Structure Evolution under Irradiation in Fast Reactors

On the base of analysis of experimental observations and critical assessment of existing models for oxide fuel structure evolution under operation conditions of fast reactors, new models for fuel restructuring and coring are proposed. The restructuring model describes coherent motion in the temperature gradient of various voids (gas bubbles, sintering pores and large lenticular pores) and grain boundaries, to which the voids are attached. As a result, the model explains elongation of thermally growing equiaxed grains and formation of columnar grains, and predicts a rapid formation of extended columnar grain zone during a relatively short initial period of fast reactor irradiation. The coring model describes formation and growth of the central void in the fuel pellet, activated by mass transport from the inner to the outer zone of the pellet under stresses induced by inhomogeneous fuel densification in the initial period of irradiation.Comment: 17 pages, 7 Figure

Ionizing radiation absorption of vascular surgeons during endovascular procedures

ObjectiveEndovascular procedures have become an integral part of a vascular surgeon’s practice. The exposure of surgeons to ionizing radiation and other safety issues have not been well studied. We investigated the radiation exposure of a team of vascular surgeons in an active endovascular unit and compared yearly dosages absorbed by various body parts among different surgeons. Patients’ radiation exposure was also assessed.MethodsThe radiation absorption of a team of vascular surgeons was prospectively monitored in a 12-month period. During each endovascular procedure, the effective body, eye, and hand radiation doses of all participating surgeons were measured by mini-thermoluminescent dosimeters (TLD) attached at the chest level under a lead apron, at the forehead at eye level, and at the hand. The type of procedure, fluoroscopy machine, fluoroscopy time, and personal and operating theatre radiation protection devices used in each procedure were also recorded. One TLD was attached to the patient’s body near the operative site to measure the patient’s dose. The yearly effective body, eye, and hand dose were compared with the safety limits of radiation for occupational exposure recommended by the International Commission on Radiation Protection (ICRP). The radiation absorption of various body parts per minute of fluoroscopy was compared among different surgeons.ResultsA total of 149 consecutive endovascular procedures were performed, including 30 endovascular aortic repairs (EVAR), 58 arteriograms with and without embolization (AGM), and 61 percutaneous transluminal angioplasty and stent (PTA/S) procedures. The cumulative fluoroscopy time was 1132 minutes. The median yearly effective body, eye, and hand dose for the surgeons were 0.20 mSv (range, 0.13 to 0.27 mSv), 0.19 mSv (range, 0.10 to 0.33 mSv) and 0.99 mSv (0.29 to 1.84 mSv) respectively, which were well below the safety limits of the ICRP. The mean body, eye, and hand dose of the chief surgeon per procedure were highest for EVAR. A significant discrepancy was observed for the average hand dose per minute of fluoroscopy among different surgeons. The mean radiation absorption of patients who underwent EVAR, AGM, and PTA/S was 12.7 mSv, 13.6 mSv, and 3.4 mSv, respectively.ConclusionWith current radiation protection practice, the radiation absorbed by vascular surgeons with a high endovascular workload did not exceed the safety limits recommended by ICRP. Variations in practice, however, can result in significant discrepancy of radiation absorption between surgeons

Instanton Cosmology and Domain Walls from M-theory and String Theory

The recent proposal by Hawking and Turok for obtaining an open inflationary universe from singular instantons makes use of low-energy effective Lagrangians describing gravity coupled to scalars and non-propagating antisymmetric tensors. In this paper we derive some exact results for Lagrangians of this type, obtained from spherical compactifications of M-theory and string theory. In the case of the S^7 compactification of M-theory, we give a detailed discussion of the cosmological solutions. We also show that the lower-dimensional Lagrangians admit domain-wall solutions, which preserve one half of the supersymmetry, and which approach AdS spacetimes near their horizons.Comment: 51 pages, Latex (3 times). Discussion and references adde

On Traversable Lorentzian Wormholes in the Vacuum Low Energy Effective String Theory in Einstein and Jordan Frames

Three new classes (II-IV) of solutions of the vacuum low energy effective string theory in four dimensions are derived. Wormhole solutions are investigated in those solutions including the class I case both in the Einstein and in the Jordan (string) frame. It turns out that, of the eight classes of solutions investigated (four in the Einstein frame and four in the corresponding string frame), massive Lorentzian traversable wormholes exist in five classes. Nontrivial massless limit exists only in class I Einstein frame solution while none at all exists in the string frame. An investigation of test scalar charge motion in the class I solution in the two frames is carried out by using the Plebanski-Sawicki theorem. A curious consequence is that the motion around the extremal zero (Keplerian) mass configuration leads, as a result of scalar-scalar interaction, to a new hypothetical "mass" that confines test scalar charges in bound orbits, but does not interact with neutral test particles.Comment: 18 page

A Study to Assess the Effectiveness of Neem Leaves Paste on Worm Infestation Among School Children In Selected School At Bangalore

Worm infestation set up an important limitation on growth and development of children. In children with borderline nutritional status, worms can precipitate nutritional failure. Worm infestation in children is normally seen in India. The common worm infestations are Threadworm, Round Worm and Hookworm. The child suffering from worms usually have below mentioned symptoms. The children have stomach pain off and on after eating his food. Lack of appetite and poor digestion. Child looks weak and sick and anemic. Sometimes a larger bunch of worms may block the intestinal tract and cause total constipation, abdominal distension and vomiting. Itching round the anal region. Intestinal parasites complete for food, damage the intestine and decrease food absorption. Light round worm infection can lead to 3 % calorie wastage. Heavy infection can lead to caloric loss of 5% of daily consumption. Hence the present study intends to assess the effectiveness of neem leaves paste on worm infestation in school children.Worm infestation contributed 13.9% of our pediatric admissions. Children between 1-2 years have increased incidence. Though most of the houses had latrine facilities, children mostly used open-air defecation. The commonest clinical presentation was gastrointestinal symptom. Associated PEM and vitamin deficiencies were present. Many children given deworming drugs had recurrence due to reinfection. Most children were anemic and eosinophilia was present in only half of them. Ultra sonogram is very useful in diagnosing worm infestation in suspecting cases. Most of them were cured with conservative line of treatment. There is a need for awareness of worm infestation, appropriate treatment i.e., regular deworming at frequent intervals.

A Study to Assess the Effectiveness of Neem Leaves Paste on Worm Infestation Among School Children In Selected School At Bangalore

Worm infestation set up an important limitation on growth and development of children. In children with borderline nutritional status, worms can precipitate nutritional failure. Worm infestation in children is normally seen in India. The common worm infestations are Threadworm, Round Worm and Hookworm. The child suffering from worms usually have below mentioned symptoms. The children have stomach pain off and on after eating his food. Lack of appetite and poor digestion. Child looks weak and sick and anemic. Sometimes a larger bunch of worms may block the intestinal tract and cause total constipation, abdominal distension and vomiting. Itching round the anal region. Intestinal parasites complete for food, damage the intestine and decrease food absorption. Light round worm infection can lead to 3 % calorie wastage. Heavy infection can lead to caloric loss of 5% of daily consumption. Hence the present study intends to assess the effectiveness of neem leaves paste on worm infestation in school children.Worm infestation contributed 13.9% of our pediatric admissions. Children between 1-2 years have increased incidence. Though most of the houses had latrine facilities, children mostly used open-air defecation. The commonest clinical presentation was gastrointestinal symptom. Associated PEM and vitamin deficiencies were present. Many children given deworming drugs had recurrence due to reinfection. Most children were anemic and eosinophilia was present in only half of them. Ultra sonogram is very useful in diagnosing worm infestation in suspecting cases. Most of them were cured with conservative line of treatment. There is a need for awareness of worm infestation, appropriate treatment i.e., regular deworming at frequent intervals.

Wormhole Geometries In f(R,T)f(R,T) Gravity

We study wormhole solutions in the framework of f (R,T) gravity where R is the scalar curvature, and T is the trace of the stress-energy tensor of the matter. We have obtained the shape function of the wormhole by specifying an equation of state for the matter field and imposing the flaring out condition at the throat. We show that in this modified gravity scenario, the matter threading the wormhole may satisfy the energy conditions, so it is the effective stress-energy that is responsible for violation of the null energy condition.Comment: 9 pages, 4 figures, published version, references adde

QTL detection for milk production traits in goats using a longitudinal model

Summary Eight paternal half-sib families were used to identify chromosomal regions associated with variation in the lactation curves of dairy goats. DNA samples from 162 animals were amplified by PCR for 37 microsatellite markers, from Capra hircus autosomes CHI3, CHI6, CHI14 and CHI20. Milk samples were collected during 6 years, and there were 897 records for milk yield (MY) and 814 for fat (FP) and protein percentage (PP). The analysis was conducted in two stages. First, a random regression model with several fixed effects was fitted to describe the lactation function, using a scale (α) plus four shape parameters: β and γ, both associated with a decrease in the slope of the curve, and δ and φ that are related to the increase in slope. Predictions of α, β, γ, δ and φ were regressed using an interval mapping model, and F-tests were used to test for quantitative trait loci (QTL) effects. Significant (p < 0.05) QTLs were found for: (i) MY: CHI6 at 70-80 cM for all parameters; CHI14 at 14 cM for δ and φ; (ii) FP: CHI14, at 63 cM was associated with β; CHI20, at 72 cM, showed association with α; (iii) PP: chromosomal regions associated with β were found at 59 cM in CHI3 and at 55 cM in CHI20 with α and γ. Analyses using more families and more animals will be useful to confirm or to reject these findings. © 2008 Blackwell Verlag, Berlin.Fil: Roldán, D.L.. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Genética; ArgentinaFil: Rabasa, Alicia Elvira. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; ArgentinaFil: Saldaño, S.. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; ArgentinaFil: Holgado, F.. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Tucuman-santiago del Estero. Campo Experimental Regional Leales; ArgentinaFil: Poli, M. A.. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Genética; ArgentinaFil: Cantet, Rodolfo Juan Carlos. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Producción Animal; Argentin

Cost-Effectiveness of Long-Acting Injectable HIV Preexposure Prophylaxis in the United States: A Cost-Effectiveness Analysis

Background: The HIV Prevention Trials Network (HPTN) 083 trial demonstrated the superiority of long-acting injectable cabotegravir (CAB-LA) compared with oral emtricitabine–tenofovir disoproxil fumarate (F/TDF) for HIV preexposure prophylaxis (PrEP). Objective: To identify the maximum price premium (that is, greatest possible price differential) that society should be willing to accept for the additional benefits of CAB-LA over tenofovir-based PrEP among men who have sex with men and transgender women (MSM/TGW) in the United States. Design: Simulation, cost-effectiveness analysis. Data Sources: Trial and published data, including estimated HIV incidence (5.32, 1.33, and 0.26 per 100 person-years for off PrEP, generic F/TDF and branded emtricitabine–tenofovir alafenamide (F/TAF), and CAB-LA, respectively); 28% 6-year PrEP retention. Annual base-case drug costs: $360 and$16 800 for generic F/TDF and branded F/TAF. Fewer side effects with branded F/TAF versus generic F/TDF were assumed. Target Population: 476 700 MSM/TGW at very high risk for HIV (VHR). Time Horizon: 10 years. Perspective: Health care system. Intervention: CAB-LA versus generic F/TDF or branded F/TAF for HIV PrEP. Outcome Measures: Primary transmissions, quality-adjusted life-years (QALYs), costs (2020 U.S. dollars), incremental cost-effectiveness ratios (ICERs; U.S. dollars per QALY), maximum price premium for CAB-LA versus tenofovir-based PrEP. Results of Base-Case Analysis: Compared with generic F/ TDF (or branded F/TAF), CAB-LA increased life expectancy by 28 000 QALYs (26 000 QALYs) among those at VHR. Branded F/ TAF cost more per QALY gained than generic F/TDF compared with no PrEP. At 10 years, CAB-LA could achieve an ICER of at most $100 000 per QALY compared with generic F/TDF at a maximum price premium of$3700 per year over generic F/TDF (CAB-LA price <$4100 per year). Results of Sensitivity Analysis: In a PrEP-eligible population at high risk for HIV, rather than at VHR (n = 1 906 800; off PrEP incidence: 1.54 per 100 person-years), CAB-LA could achieve an ICER of at most$100 000 per QALY versus generic F/TDF at a maximum price premium of $1100 per year over generic F/TDF (CAB-LA price <$1500 per year). Limitation: Uncertain clinical and economic benefits of averting future transmissions. Conclusion: Effective oral PrEP limits the additional price society should be willing to pay for CAB-LA