Fixed-node diffusion Monte Carlo study of the structures of m-benzyne

Diffusion Monte Carlo (DMC) calculations are performed on the monocyclic and bicyclic forms of m-benzyne, which are the equilibrium structures at the CCSD(T) and CCSD levels of coupled cluster theory. We employed multi-configuration self-consistent field trial wave functions which are constructed from a carefully selected 8-electrons-in-8-orbitals complete active space [CAS(8,8)], with CSF coefficients that are reoptimized in the presence of a Jastrow factor. The DMC calculations show that the monocyclic structure is lower in energy than the bicyclic structure by 1.9(2) kcal/mole, in excellent agreement with the best coupled cluster results.Comment: 5 pages, 2 figures. to be published in JC

Classification of N=2 supersymmetric CFT_{4}s: Indefinite Series

Using geometric engineering method of 4D $\mathcal{N}=2$ quiver gauge theories and results on the classification of Kac-Moody (KM) algebras, we show on explicit examples that there exist three sectors of $\mathcal{N}=2$ infrared CFT$_{4}$s. Since the geometric engineering of these CFT$_{4}$s involve type II strings on K3 fibered CY3 singularities, we conjecture the existence of three kinds of singular complex surfaces containing, in addition to the two standard classes, a third indefinite set. To illustrate this hypothesis, we give explicit examples of K3 surfaces with H$_{3}^{4}$ and E$_{10}$ hyperbolic singularities. We also derive a hierarchy of indefinite complex algebraic geometries based on affine $A_{r}$ and T$$ algebras going beyond the hyperbolic subset. Such hierarchical surfaces have a remarkable signature that is manifested by the presence of poles.Comment: 12 pages, 2 figure

Interfacial effects in fast reactors

"May 1979."Also written as a Ph. D. thesis by the first author and supervised by the second author, MIT Dept. of Nuclear Engineering, 1979Includes bibliographical references (pages 191-193)The problem of increased resonance capture rates near zone interfaces in fast reactor media has been examined both theoretically and experimentally. An interface traversing assembly was designed, constructed and employed to measure U-238 capture rates near the blanket-reflector interface in the MIT Blanket Test Facility. Prior MIT experiments on a thorium-uranium interface in a blanket assembly were also reanalyzed. Extremely localized fertile capture rate increases of on the order of 50% were measured immediately at the interfaces relative to extrapolation of asymptotic interior traverses, and relative to state-of-the-art (LIB-IV, SPHINX, ANISN/2DB) calculations which employ infinite-medium self-shileding throughout a given zone. A method was developed to compute a spatially varying background scattering cross section per absorber nucleus, a , which takes into account both homogeneous and heterogeneous effec~s on the interface flux transient. This permitted use of the standard self-shielding factor method (Bondarenko f-factors) to generate modified cross sections for thin layers near the interfaces. Calculations of the MIT experiments using this approach yielded good agreement with the measured data.U.S. Department of Energy contract EY-76-S-02-225

Brane Realizations of Quantum Hall Solitons and Kac-Moody Lie Algebras

Using quiver gauge theories in (1+2)-dimensions, we give brane realizations of a class of Quantum Hall Solitons (QHS) embedded in Type IIA superstring on the ALE spaces with exotic singularities. These systems are obtained by considering two sets of wrapped D4-branes on 2-spheres. The space-time on which the QHS live is identified with the world-volume of D4-branes wrapped on a collection of intersecting 2-spheres arranged as extended Dynkin diagrams of Kac-Moody Lie algebras. The magnetic source is given by an extra orthogonal D4-brane wrapping a generic 2-cycle in the ALE spaces. It is shown as well that data on the representations of Kac-Moody Lie algebras fix the filling factor of the QHS. In case of finite Dynkin diagrams, we recover results on QHS with integer and fractional filling factors known in the literature. In case of hyperbolic bilayer models, we obtain amongst others filling factors describing holes in the graphene.Comment: Lqtex; 15 page

The Association Between Pitch Conditions and the Incidence of Injury in Rugby

Background: Environmental conditions have been shown to influence incidence of rugby injuries. Harsh weather conditions and detrimental effect on poor Kenyan rugby pitches create a unique environment for injury exposure. We conducted a whole population prospective cohort study to determine the association of pitch conditions with injury incidence and severity.Methods: The study was conducted on 364 registered Kenya Rugby Union (KRU) players throughout the 2010 15-aside season. The injury incidence was calculated as injuries per 1000 match player hours (mph). Pitches were categorized into good and suboptimal based on quality indicators of ground characteristics. Injuries were defined and recorded according to the Rugby International Consensus Group (RICG) protocol and compared between the pitches.Results: One hundred and two injuries were recorded in 60 league games (2400 mph). Twenty nine of the 60 league games were played in the category B (suboptimal condition) pitches. The overall incidence of injuries was 42.50/1000mph. Good pitches had an injury of 29.0 injuries/1000mph (95% CI 0.81- 1.61) compared to 56.9 injuries/1000mph (95% CI 1.76- 2.90) for suboptimal pitches.Conclusion: Although the overall Kenyan injury rate is comparable to the amateur level incidence from other studies, the higher rate associated with suboptimal pitches suggests interventions that can target pitch optimization.Keywords: Injury rate, Ground conditions, Rugby, Kenya

Common carotid intimal medial thickness in a Kenyan population

Carotid intimal medial thickness, a marker for early atherosclerosis, has high clinical utility. It shows gender, regional, age and ethnic differences but data from black African populations are scarce. This study describes the carotid intimal medial thickness in a black Kenyan population. One hundred and fifty histological samples from 25 males and 25 female left common carotid arteries were routinely processed for light microscopy and stained using Mason’s Trichrome stain. The intimal medial thickness was measured on the photomicrographs using the Scion Multiscan software. The mean age of the cases was 28+19yrs. Mean carotid intimal medial thickness is higher in males (0.97+0.22) than females (0.77+0.06), p=0.05 and increases distally. Carotid intimal medial thickness increased with age being 0.5+0.16mm, 0.87+0.24mm and 1.21+0.36 mm for the age groups 0-20yrs, 21-40yrs and 41-60yrs respectively (p=0.035). Carotid intimal medial thickness in black Africans is similar to that reported for Caucasian populations. It is higher in males, increases distally and with age.Keywords: Carotid Intimal medial thickness, atherosclerosi