Quantum orbifold Hirzebruch-Riemann-Roch theorem in genus zero

We introduce K-theoretic Gromov-Witten invariants of algebraic orbifold target spaces. Using the methods developed by Givental-Tonita we characterize Giventals Lagrangian cone of quantum K theory of orbifolds in terms of the cohomological cone.Comment: 26 page

Corruption In Developing Countries: What Keeping It In The Family Means For Everyone Else

The United Nations estimates that 30 per cent of all international development funding is lost to corruption. Identifying and understanding the dynamics of how such corruption occurs at the ground level could help to reduce opportunities for the diversion of funds from public purposes to private uses. An analysis of two highly publicized corruption cases in Kenya and one in Afghanistan identifies some common characteristics that may also be present in other cases around the world. The characteristics fall into four categories: (1) political, social, and cultural; (2) governance; (3) people; and (4) international. Different understandings of corruption, weak government and laws, illegitimate involvement of powerful politicians or their relatives, and ineffective international mechanisms for preventing corruption all contribute to the loss of development funding. The article describes these characteristics and discusses remedies for addressing them

Twisted K-theoretic Gromov-Witten invariants

We introduce twisted K-theoretic Gromov-Witten (GW) invariants in the frameworks of both "ordinary" and permutation-equivariant K-theoretic GW theory defined recently by Givental. We focus on the case when the twisting is given by the Euler class of an index bundle which allows one (under a convexity assumption on the bundle) to relate K-theoretic GW invariants of hypersurfaces with those of the ambient space. Using the methods developed in Givental and Tonita (Math Sci Res Inst Publ 62:43–92. Cambridge Univ. Press, Cambridge, 2014) we characterize the range of the $J$-function of the twisted theory in terms of the untwisted theory. As applications we use the D_q module structure in the permutation-equivariant case to generalize results of Givental (Permutation-equivariant quantum K-theory I–VIII. https://math.berkeley.edu/~giventh/perm/perm.html, 2015): we prove a general "quantum Lefschetz" type theorem for complete intersections given by zero sections of convex vector bundles and we relate points on the cones of the total space with those of the base of a toric fibration

Black hole-neutron star mergers and short GRBs: a relativistic toy model to estimate the mass of the torus

The merger of a binary system composed of a black hole and a neutron star may leave behind a torus of hot, dense matter orbiting around the black hole. While numerical-relativity simulations are necessary to simulate this process accurately, they are also computationally expensive and unable at present to cover the large space of possible parameters, which include the relative mass ratio, the stellar compactness, and the black hole spin. To mitigate this and provide a first reasonable coverage of the space of parameters, we have developed a method for estimating the mass of the remnant torus from black hole-neutron star mergers. The toy model makes use of an improved relativistic affine model to describe the tidal deformations of an extended tri-axial ellipsoid orbiting around a Kerr black hole and measures the mass of the remnant torus by considering which of the fluid particles composing the star are on bound orbits at the time of the tidal disruption. We tune the toy model by using the results of fully general-relativistic simulations obtaining relative precisions of a few percent and use it to extensively investigate the space of parameters. In this way we find that the torus mass is largest for systems with highly spinning black holes, small stellar compactnesses, and large mass ratios. As an example, tori as massive as ~1.33 solar masses can be produced for a very extended star with compactness of ~0.1 inspiralling around a black hole with dimensionless spin equal to 0.85 and mass ratio of about 0.3. However, for a more astrophysically reasonable mass ratio of ~0.14 and a canonical value of the stellar compactness of ~0.145, the toy model sets a considerably smaller upper limit to the torus mass of less than ~0.34 solar masses.Comment: Added new figure and new table to confirm agreement with simulations; matches version accepted for publication in Ap

Freely available prostate specific antigen testing in a population : testing patterns and outcomes on prostate cancer The Saskatchewan Experience

Background: The prostate specific antigen (PSA) test has been available for physicians and free of charge to residents in Saskatchewan since 1990. The PSA test witnessed great growth in use indicative of screening but it was unknown who was being tested, how often, which physicians were ordering PSA tests, or what the variation in utilization was in the population. Whether widespread use of the PSA test resulted in a stage shift among newly diagnosed prostate cancers or changed the clinical management of the disease was also unknown. The purpose of this research was to describe in detail how the PSA test is being used in the Saskatchewan population and investigate the impact of testing on the diagnosis and clinical management of prostate cancer during the PSA era. Methods: Individual records were retrieved from the two labs in Saskatchewan capable of analyzing PSA serum samples. The PSA data represented almost all PSA tests in the population for the five-year period 1997-2001. The PSA data included date of the PSA test, a unique identifier of the men tested, test results including total PSA and the free-PSA amount (for November 1999 to December 2001), and an ID of the physician who ordered the test. This data was linked to the population-based Saskatchewan Cancer Registry to determine who had a previous or subsequent prostate cancer diagnosis and to secure tumour characteristics and clinical management data. This combined data was then linked to Saskatchewan Health data files to obtain information about biopsy procedures and to determine the geographic residence of men at the time of their PSA tests. De-identified data was returned for descriptive analysis. Results: Over 60% of men aged 50 and over had at least one PSA test during 1997 to 2001. Even among men 40-49, 27% had at least one PSA test and there were over 5,300 tests done in men under 40 years of age. Sixteen percent of men 40-49 who had PSA tests had more than one and this percentage increased with age to 59.4% for men in their 70’s. Over 80% of all PSA tests were ordered by general practitioners and there were significant geographic variations in testing patterns. Knowledge of the free-PSA-ratio, which began in 1999, reduced biopsy rates 4.7% and increased cancer detection 8.7% for men with total PSA test results in the 4.0-10.0ng/ml range, however these rates were also very age specific. The age-adjusted incidence rate of organ confined disease increased from 38.5 per 100,000 to 108.8 per 100,000 from 1985 to 2001. Almost 80% of prostate cancers were detected by needle biopsy in 2001 compared to only 34% in 1985, while 20% of cases in 2001 were treated with radical surgery compared to only 2% for 1985. Mortality rates have remained stable up to 2001. Conclusion: PSA testing is very common in Saskatchewan consistent with extensive screening activity. Conflicting guidelines and the universal availability of the test has resulted in significant inappropriate testing and considerable variation of use. Most prostate cancers are now found by needle biopsy and are organ confined at the time of diagnosis. No benefit in prostate cancer mortality has yet been realized in Saskatchewan from extensive PSA testing

A virtual Kawasaki formula

Kawasaki's formula is a tool to compute holomorphic Euler characteristics of vector bundles on a compact orbifold X. Let X be an orbispace with perfect obstruction theory which admits an embedding in a smooth orbifold. One can then construct the virtual structure sheaf and the virtual fundamental class of X. In this paper we prove that Kawasaki's formula behaves well " with working virtually" on X in the following sense: if we replace the structure sheaves, tangent and normal bundles in the formula by their virtual counterparts then Kawasaki's formula stays true. Our motivation comes from studying the quantum K-theory of a complex manifold X, with the formula applied to Kontsevich' moduli spaces of genus 0 stable maps to X.Comment: 8 page

Combating the Matthew effect for English language learners : making thinking visible in the secondary English classroom

This study sets out to answer the call for explicit instruction in critical thinking for ELL. Using action research and qualitative methodology, I examine the effect of implementing the cognitive apprenticeship paradigm with ELL studying in a mainstream secondary English class using the American curriculum. I center instruction on authentic texts and scaffold critical literacy and thinking tasks for instructional interventions. The data generated by the study includes written responses and reflections by the participants. This data is analyzed using research into cognitive theory and critical thinking pedagogy. The results support the cognitive apprenticehip model as one means for improving the higher literacy of ELL, regardless of level and background. The findings of this study contribute to the discussion of how to bridge the achievement gap between ELL and their native speaking peers and provide an avenue to advance their academic success.English StudiesM.A. (with specialisation in TESOL (Teaching English to Speakers of other languages)