A priori mixing of mesons and the |Delta I|=1/2 rule in K\to\pi\pi

We consider the hypothesis of a priori mixings in the mass eigenstates of mesons to obtain the |Delta I|=1/2 rule in K\to\pi\pi. The Hamiltonian responsible for the transition is the strong interacting one. The experimental data are described using the isospin symmetry relations between the strong coupling constants

Stochastic Invariants for Probabilistic Termination

Termination is one of the basic liveness properties, and we study the termination problem for probabilistic programs with real-valued variables. Previous works focused on the qualitative problem that asks whether an input program terminates with probability~1 (almost-sure termination). A powerful approach for this qualitative problem is the notion of ranking supermartingales with respect to a given set of invariants. The quantitative problem (probabilistic termination) asks for bounds on the termination probability. A fundamental and conceptual drawback of the existing approaches to address probabilistic termination is that even though the supermartingales consider the probabilistic behavior of the programs, the invariants are obtained completely ignoring the probabilistic aspect. In this work we address the probabilistic termination problem for linear-arithmetic probabilistic programs with nondeterminism. We define the notion of {\em stochastic invariants}, which are constraints along with a probability bound that the constraints hold. We introduce a concept of {\em repulsing supermartingales}. First, we show that repulsing supermartingales can be used to obtain bounds on the probability of the stochastic invariants. Second, we show the effectiveness of repulsing supermartingales in the following three ways: (1)~With a combination of ranking and repulsing supermartingales we can compute lower bounds on the probability of termination; (2)~repulsing supermartingales provide witnesses for refutation of almost-sure termination; and (3)~with a combination of ranking and repulsing supermartingales we can establish persistence properties of probabilistic programs. We also present results on related computational problems and an experimental evaluation of our approach on academic examples.Comment: Full version of a paper published at POPL 2017. 20 page

Mirror matter admixtures in K_L \to \gamma\gamma

Based on possible albeit tiny, admixtures of mirror matter in ordinary mesons we study the K_L \to \gamma\gamma transition. We find that this process can be described with a small SU(3) symmetry breaking of only 3%. We also determine the eta-eta' mixing angle and the pseudoscalar decay constants. The results for these parameters are consistent with some obtained in the literature. They favor two recent determinations; one based on two analytical constraints, and another one based on next-to-leading order power corrections

Non-polynomial Worst-Case Analysis of Recursive Programs

We study the problem of developing efficient approaches for proving worst-case bounds of non-deterministic recursive programs. Ranking functions are sound and complete for proving termination and worst-case bounds of nonrecursive programs. First, we apply ranking functions to recursion, resulting in measure functions. We show that measure functions provide a sound and complete approach to prove worst-case bounds of non-deterministic recursive programs. Our second contribution is the synthesis of measure functions in nonpolynomial forms. We show that non-polynomial measure functions with logarithm and exponentiation can be synthesized through abstraction of logarithmic or exponentiation terms, Farkas' Lemma, and Handelman's Theorem using linear programming. While previous methods obtain worst-case polynomial bounds, our approach can synthesize bounds of the form $\mathcal{O}(n\log n)$ as well as $\mathcal{O}(n^r)$ where $r$ is not an integer. We present experimental results to demonstrate that our approach can obtain efficiently worst-case bounds of classical recursive algorithms such as (i) Merge-Sort, the divide-and-conquer algorithm for the Closest-Pair problem, where we obtain $\mathcal{O}(n \log n)$ worst-case bound, and (ii) Karatsuba's algorithm for polynomial multiplication and Strassen's algorithm for matrix multiplication, where we obtain $\mathcal{O}(n^r)$ bound such that $r$ is not an integer and close to the best-known bounds for the respective algorithms.Comment: 54 Pages, Full Version to CAV 201

Understanding Parents\u27 Views toward the Newly Enacted HPV Vaccine School Entry Policy in Puerto Rico: A Qualitative Study

BACKGROUND: The Human papillomavirus vaccine (HPV) is an essential tool for the prevention of HPV-related cancers. In Puerto Rico, the Secretary of Health established a school entry requirement of at least one dose of HPV vaccination in girls and boys aged 11 and 12 years, taking effect in August 2018. Our study aimed to examine parents\u27 and guardians\u27 views of unvaccinated children about the process of implementation of the new HPV vaccination school entry policy in Puerto Rico and identify potential barriers and facilitators related to the implementation of this requirement. METHODS: During April through November 2019, we conducted three focus groups (n = 12) and eight in-depth semi-structured interviews with parents of children aged 11 and 12 who had not yet initiated the HPV vaccine series. The interview topics addressed were: perception of vaccination, HPV vaccine and it is inclusion as new school entry requirement practice, procedure of the sources of information, influencers, and willingness to change. The interviews were recorded and transcribed by our staff members. We identified emergent themes through thematic analysis. RESULTS: The participants\u27 perspective on the HPV vaccine school requirement was mixed. Lack of information of the HPV vaccines and lack of communication about the school-entry requirement were the themes most mentioned in the interviews. Moreover, previous negative experiences from friends or family members and adverse effects deterred some participants from vaccinating their kids. We discussed barriers in the process of soliciting an exemption. CONCLUSION: Most barriers mentioned by study participants are modifiable. Information about the HPV vaccine mandate\u27s implementation and educational materials regarding HPV vaccine safety need to be provided to address parents\u27 concerns related to the vaccine\u27s side effects. Schools (teachers, principal directors, and administrative staff), the government, and parent organizations need to be part of these efforts. This multilevel approach will help to improve disseminating information about HPV vaccination to clarify doubts and misinformation among parents

Finding polynomial loop invariants for probabilistic programs

Quantitative loop invariants are an essential element in the verification of probabilistic programs. Recently, multivariate Lagrange interpolation has been applied to synthesizing polynomial invariants. In this paper, we propose an alternative approach. First, we fix a polynomial template as a candidate of a loop invariant. Using Stengle's Positivstellensatz and a transformation to a sum-of-squares problem, we find sufficient conditions on the coefficients. Then, we solve a semidefinite programming feasibility problem to synthesize the loop invariants. If the semidefinite program is unfeasible, we backtrack after increasing the degree of the template. Our approach is semi-complete in the sense that it will always lead us to a feasible solution if one exists and numerical errors are small. Experimental results show the efficiency of our approach.Comment: accompanies an ATVA 2017 submissio

Translating Evidence-Based Falls Prevention into Clinical Practice in Nursing Facilities: Results and Lessons from a Quality Improvement Collaborative

OBJECTIVES—To describe the changes in process of care before and after an evidence-based fall reduction quality improvement collaborative in nursing facilities. DESIGN—Natural experiment with non-participating facilities serving as controls. SETTING—Community nursing homes. PARTICIPANTS—Thirty-six participating and 353 non-participating nursing facilities in North Carolina. INTERVENTION—Two in-person learning sessions, monthly teleconferences, and an e-mail discussion list over 9 months. The change package emphasized screening, labeling, and risk-factor reduction. MEASUREMENTS—Compliance was measured using facility self-report and chart abstraction (n = 832) before and after the intervention. Fall rates as measured using the Minimum Data Set (MDS) were compared with those of non-participating facilities as an exploratory outcome. RESULTS—Self-reported compliance with screening, labeling, and risk-factor reduction approached 100%. Chart abstraction revealed only modest improvements in screening (51% to 68%, P<.05), risk-factor reduction (4% to 7%, P = .30), and medication assessment (2% to 6%, P = .34). There was a significant increase in vitamin D prescriptions (40% to 48%, P = .03) and decrease in sedative-hypnotics (19% to 12%, P = .04) but no change in benzodiazepine, neuroleptic, or calcium use. No significant changes in proportions of fallers or fall rates were observed according to chart abstraction (28.6% to 37.5%, P = .17), MDS (18.2% to 15.4%, P = .56), or self-report (6.1–5.6 falls/1,000 bed days, P = .31). CONCLUSON—Multiple-risk-factor reduction tasks are infrequently implemented, whereas screening tasks appear more easily modifiable in a real-world setting. Substantial differences between self-reported practice and medical record documentation require that additional data sources be used to assess the change-in-care processes resulting from quality improvement programs. Interventions to improve interdisciplinary collaboration need to be developed

Invariant Synthesis for Incomplete Verification Engines

We propose a framework for synthesizing inductive invariants for incomplete verification engines, which soundly reduce logical problems in undecidable theories to decidable theories. Our framework is based on the counter-example guided inductive synthesis principle (CEGIS) and allows verification engines to communicate non-provability information to guide invariant synthesis. We show precisely how the verification engine can compute such non-provability information and how to build effective learning algorithms when invariants are expressed as Boolean combinations of a fixed set of predicates. Moreover, we evaluate our framework in two verification settings, one in which verification engines need to handle quantified formulas and one in which verification engines have to reason about heap properties expressed in an expressive but undecidable separation logic. Our experiments show that our invariant synthesis framework based on non-provability information can both effectively synthesize inductive invariants and adequately strengthen contracts across a large suite of programs

WASP-4b Arrived Early for the TESS Mission

The Transiting Exoplanet Survey Satellite (TESS) recently observed 18 transits of the hot Jupiter WASP-4b. The sequence of transits occurred 81.6 $\pm$ 11.7 seconds earlier than had been predicted, based on data stretching back to 2007. This is unlikely to be the result of a clock error, because TESS observations of other hot Jupiters (WASP-6b, 18b, and 46b) are compatible with a constant period, ruling out an 81.6-second offset at the 6.4$\sigma$ level. The 1.3-day orbital period of WASP-4b appears to be decreasing at a rate of $\dot{P} = -12.6 \pm 1.2$ milliseconds per year. The apparent period change might be caused by tidal orbital decay or apsidal precession, although both interpretations have shortcomings. The gravitational influence of a third body is another possibility, though at present there is minimal evidence for such a body. Further observations are needed to confirm and understand the timing variation.Comment: AJ accepte

Orbitopatía tiroidea: protocolo de manejo basado en revisión de la evidencia

La orbitopatía tiroidea es una patología potencialmente grave que amenaza la visión. Es la manifestación extratiroidea más frecuente de la enfermedad de Graves y, aunque la prevalencia no está evaluada en Colombia, puede producir pérdida de la visión, con consecuencias catastróficas. Teniendo en cuenta lo anterior, se realizó este trabajo con el objetivo de describir su enfoque diagnóstico y terapéutico basado en la mejor evidencia disponible. Se elaboró un protocolo de manejo aplicable a nuestro medio y se realizó una evaluación y adaptación de la guía European Group on Graves’ Orbitopathy (EUGOGO) del 2016 (1). Para la evaluación se usó la herramienta AGREE IIy se utilizó la metodología GRADE para la graduación de la calidad de la evidencia y formulación de las recomendaciones (2). Adicionalmente, se hizo una revisión sistemática de la literatura con el objetivo de evaluar la eficacia de la terapia biológica en el manejo de la orbitopatía de Graves. Se presentan las recomendaciones para el diagnóstico, tratamiento y seguimiento. Se recalca la importancia de contar con un equipo multidisciplinario con experiencia en el manejo de la orbitopatía tiroidea (endocrinología, oftalmología, cirugía de órbita, radioterapia y reumatología), idealmente en un centro de tercer nivel de atención. Es esencial la clasificación adecuada para determinar qué pacientes se benefician del tratamiento inmunosupresor. Si se maneja de forma oportuna, se puede lograr una disminución de la aparición de secuelas irreversible