Shape Analysis in the Absence of Pointers and Structure

discover properties of dynamic and/or mutable structures. We ask, “Is there an equivalent to shape analysis for purely functional programs, and if so, what ‘shapes ’ does it discover? ” By treating binding environments as dynamically allocated structures, by treating bindings as addresses, and by treating value environments as heaps, we argue that we can analyze the “shape ” of higher-order functions. To demonstrate this, we enrich an abstract-interpretive control-flow analysis with principles from shape analysis. In particular, we promote “anodization ” as a way to generalize both singleton abstraction and the notion of focusing, and we promote “binding invariants ” as the analog of shape predicates. Our analysis enables two optimizations known to be beyond the reach of control-flow analysis (globalization and super-β inlining) and one previously unknown optimization (higher-order rematerialization).

Family Unification, Exotic States and Light Magnetic Monopoles

Models with fermions in bifundamental representations can lead naturally to family unification as opposed to family replication. Such models typically predict (exotic) color singlet states with fractional electric charge, and magnetic monopoles with multiple Dirac charge. The exotics may be at the TeV scale, and relatively light magnetic monopoles (greater than about 10^7 GeV) can be present in the galaxy with abundance near the Parker bound. We focus on three family SU(4)XSU(3)XSU(3) models.Comment: 37 page

HIV retesting in pregnant women in South Africa: Outcomes of a quality improvement project targeting health systems’ weaknesses

Introduction: South Africa is moving towards achieving elimination of mother-to-child transmission (eMTCT) but gaps remain in eMTCT programmes. Documenting successful outcomes of health systems interventions to address these gaps could encourage similar initiatives in the future.Methods: We describe the effectiveness of a Quality Improvement Project (QIP) to improve HIV retesting rates during pregnancy among women who had previously tested negative by redesigning the clinic process. Eight poorly-performing clinics were selected and compared with eight better-performing control clinics in a subdistrict in North West Province. Over nine months, root cause analysis and testing of change ideas using Plan-Do-Study-Act cycles were used to identify and refine interventions. Analysis of patient flow showed that women were referred for retesting following their nurse-driven antenatal visits, and many left without retesting as this would have further prolonged their visit. Processes were redesigned and standardised, where a counsellor was charged with retesting patients before antenatal consults. Staff were mentored on data collection and interpretation process. Quality improvement nurse advisors monitored indicators bi-weekly and adjusted interventions accordingly.Results: Retesting in intervention clinics rose from 36% in the three months pre-intervention to full coverage at month nine. At the end of the study, retesting in intervention clinics was 20% higher than in controls. Retesting also increased in the subdistrict overall.Conclusion: Service coverage and overall impact of HIV programmes can be raised through care-process analysis that optimises patient flow, supported by targeted QI interventions. These QI methodologies may be effective elsewhere for identifying new HIV infections in pregnant/breastfeeding women, and possibly in other services

The case for open science: rare diseases.

The premise of Open Science is that research and medical management will progress faster if data and knowledge are openly shared. The value of Open Science is nowhere more important and appreciated than in the rare disease (RD) community. Research into RDs has been limited by insufficient patient data and resources, a paucity of trained disease experts, and lack of therapeutics, leading to long delays in diagnosis and treatment. These issues can be ameliorated by following the principles and practices of sharing that are intrinsic to Open Science. Here, we describe how the RD community has adopted the core pillars of Open Science, adding new initiatives to promote care and research for RD patients and, ultimately, for all of medicine. We also present recommendations that can advance Open Science more globally

The effects of aging of scientists on their publication and citation patterns

The average age at which U.S. researchers get their first grant from NIH has increased from 34.3 in 1970, to 41.7 in 2004. These data raise the crucial question of the effects of aging on the scientific creativity and productivity of researchers. Those who worry about the aging of scientists usually believe that the younger they are the more creative and productive they will be. Using a large population of 13,680 university professors in Quebec, we show that, while scientific productivity rises sharply between 28 and 40, it increases at a slower pace between 41 and 50 and stabilizes afterward until retirement for the most active researchers. The average scientific impact per paper decreases linearly until 50-55 years old, but the average number of papers in highly cited journals and among highly cited papers rises continuously until retirement. Our results clearly show for the first time the natural history of the scientific productivity of scientists over their entire career and bring to light the fact that researchers over 55 still contribute significantly to the scientific community by producing high impact papers.Comment: 12 pages, 4 figure

Abstract interpreters for free

... semantics bear an uncanny resemblance. In this work, we present an analysis-design methodology that both explains and exploits that resemblance. Specifically, we present a two-step method to convert a smallstep concrete semantics into a family of sound, computable abstract interpretations. The first step re-factors the concrete state-space to eliminate recursive structure; this refactoring of the state-space simultaneously determines a store-passing-style transformation on the underlying concrete state-space and a Galois connection simultaneously. The Galois connection allows the calculation of the “optimal ” abstract interpretation. The two-step process is unambiguous, but nondeterministic: at each step, analysis designers face choices. Some of these choices ultimately influence properties such as flow-, field- and context-sensitivity. Thus, under the method, we can give the emergence of these properties a graphtheoretic characterization. To illustrate the method, we systematically abstract the continuation-passing style lambda calculus to arrive at two distinct families of analyses. The first is the well-known k-CFA family interpretations, none of which appear in the literature on static analysis of higher-order programs

Widening for Control-Flow

Abstract. We present a parameterized widening operator that determines the control-flow sensitivity of an analysis, i.e., its flow-sensitivity, context-sensitivity, and path-sensitivity. By instantiating the operator’s parameter in different ways, semantics of the analysis itself. Similarly, the analysis can be implemented so that its sensitivity can be tuned without changing the analysis implementation. Thus, the sensitivity is an independent concern, allowing the analysis designer to design and implement the analysis without worrying about its sensitivity and then easily experiment with different sensitivities after the fact. Additionally, we show that the space of control-flow sensitivities induced by this widening operator forms a lattice. The lattice meet and join operators are the product and sum of sensi-tivities, respectively. They can be used to automatically create new sensitivities from existing ones without manual effort. The sum operation in particular is a novel construction, which creates a new sensitivity less precise than either of its operands but containing elements of both.