Bit-Vector Model Counting using Statistical Estimation

Approximate model counting for bit-vector SMT formulas (generalizing \#SAT) has many applications such as probabilistic inference and quantitative information-flow security, but it is computationally difficult. Adding random parity constraints (XOR streamlining) and then checking satisfiability is an effective approximation technique, but it requires a prior hypothesis about the model count to produce useful results. We propose an approach inspired by statistical estimation to continually refine a probabilistic estimate of the model count for a formula, so that each XOR-streamlined query yields as much information as possible. We implement this approach, with an approximate probability model, as a wrapper around an off-the-shelf SMT solver or SAT solver. Experimental results show that the implementation is faster than the most similar previous approaches which used simpler refinement strategies. The technique also lets us model count formulas over floating-point constraints, which we demonstrate with an application to a vulnerability in differential privacy mechanisms

Efficacy of rifabutin-based triple therapy as second-line treatment to eradicate helicobacter pylori infection

<p>Abstract</p> <p>Background</p> <p>Rifabutin has been found to be effective in multi-resistant patients after various treatment cycles for Helicobacter pylori (HP) infection, but it has not been analysed as a second-line treatment. Therefore, we seek to compare the effectiveness of a treatment regimen including rifabutin versus conventional quadruple therapy (QT).</p> <p>Methods</p> <p>Open clinical trial, randomised and multi-centre, of two treatment protocols: A) Conventional regime -QT- (omeprazole 20 mg bid, bismuth citrate 120 mg qid, tetracycline 500 mg qid and metronidazole 500 mg tid); B) Experimental one -OAR- (omeprazole 20 mg bid, amoxicillin 1 gr bid, and rifabutin 150 mg bid), both taken orally for 7 days, in patients with HP infection for whom first-line treatment had failed. Eradication was determined by Urea Breath Test (UBT). Safety was determined by the adverse events.</p> <p>Results</p> <p>99 patients were randomised, QT, n = 54; OAR, n = 45. The two groups were homogeneous. In 8 cases, treatment was suspended (6 in QT and 2 in OAR). The eradication achieved, analysed by ITT, was for QT, 38 cases (70.4%), and for OAR, 20 cases (44.4%); p = 0.009, OR = 1.58. Of the cases analysed PP, QT were 77.1%; OAR, 46.5%; p = 0.002. Adverse effects were described in 64% of the QT patients and in 44% of the OAR patients (p = 0.04).</p> <p>Conclusion</p> <p>A 7-day rifabutin-based triple therapy associated to amoxicillin and omeprazole at standard dose was not found to be effective as a second-line rescue therapy. The problem with quadruple therapy lies in the adverse side effects it provokes. We believe the search should continue for alternatives that are more comfortably administered and that are at least as effective, but with fewer adverse side effects.</p> <p>Trial Registration</p> <p>Current Controlled Trials ISRCTN81058036</p

Duality covariant non-BPS first order systems

We study extremal black hole solutions to four dimensional N=2 supergravity based on a cubic symmetric scalar manifold. Using the coset construction available for these models, we define the first order flow equations implied by the corresponding nilpotency conditions on the three-dimensional scalar momenta for the composite non-BPS class of multi-centre black holes. As an application, we directly solve these equations for the single-centre subclass, and write the general solution in a manifestly duality covariant form. This includes all single-centre under-rotating non-BPS solutions, as well as their non-interacting multi-centre generalisations.Comment: 31 pages, v2: Discussion of the quadratic constraint clarified, references added, typos corrected, published versio

First-order flows and stabilisation equations for non-BPS extremal black holes

We derive a generalised form of flow equations for extremal static and rotating non-BPS black holes in four-dimensional ungauged N = 2 supergravity coupled to vector multiplets. For particular charge vectors, we give stabilisation equations for the scalars, analogous to the BPS case, describing full known solutions. Based on this, we propose a generic ansatz for the stabilisation equations, which surprisingly includes ratios of harmonic functions.Comment: 27 pages; v2: presentation improved and references added as in the published versio

Black holes and black strings of N=2, d=5 supergravity in the H-FGK formalism

We study general classes and properties of extremal and non-extremal static black-hole solutions of N=2, d=5 supergravity coupled to vector multiplets using the recently proposed H-FGK formalism, which we also extend to static black strings. We explain how to determine the integration constants and physical parameters of the black-hole and black-string solutions. We derive some model-independent statements, including the transformation of non-extremal flow equations to the form of those for the extremal flow. We apply our methods to the construction of example solutions (among others a new extremal string solution of heterotic string theory on K_3 \times S^1). In the cases where we have calculated it explicitly, the product of areas of the inner and outer horizon of a non-extremal solution coincides with the square of the moduli-independent area of the horizon of the extremal solution with the same charges.Comment: 33 pages. Revised version: references added. No other change

Evolução na utilização e nos gastos de uma operadora de saúde

Brazil’s aging population and the rising number of people reliant upon the country’s supplementary healthcare system have elicited the concern of public and private managers regarding the increase in healthcare costs. In this paper, the costs per gender, per type of medical expenses and per age group of a major Brazilian self-managed healthcare provider between 2007 and 2013 were analyzed. This healthcare provider is of interest because, besides portraying a single condition of revenue growth restricted to the existing contributors, it also replicates the demographic profile expected for Brazil in 2050, when approximately one-third of its population will be over 60 years of age. The analyses confirm the current literature as they show an increase in healthcare plan usage by the elderly and the difference between admission rates by gender. They also reveal an increase in average length of stay in hospital and the increase in medical costs far above inflation, especially for materials and medicines. It is hoped that this study will help scholars and others interested in comparisons of medical expense trends, especially by age and sex, and that it encourages further collaboration on the sustainability of health insurance providers in Brazil

Beyond the required LISA free-fall performance: new LISA pathfinder results down to 20 μHz

In the months since the publication of the first results, the noise performance of LISA Pathfinder has improved because of reduced Brownian noise due to the continued decrease in pressure around the test masses, from a better correction of noninertial effects, and from a better calibration of the electrostatic force actuation. In addition, the availability of numerous long noise measurement runs, during which no perturbation is purposely applied to the test masses, has allowed the measurement of noise with good statistics down to 20  μHz. The Letter presents the measured differential acceleration noise figure, which is at (1.74±0.05)  fm s^{-2}/sqrt[Hz] above 2 mHz and (6±1)×10  fm s^{-2}/sqrt[Hz] at 20  μHz, and discusses the physical sources for the measured noise. This performance provides an experimental benchmark demonstrating the ability to realize the low-frequency science potential of the LISA mission, recently selected by the European Space Agency

Pharmaceutical services for endemic situations in the Brazilian Amazon: organization of services and prescribing practices for Plasmodium vivax and Plasmodium falciparum non-complicated malaria in high-risk municipalities

<p>Abstract</p> <p>Background</p> <p>In spite of the fact that pharmaceutical services are an essential component of all malaria programmes, quality of these services has been little explored in the literature. This study presents the first results of the application of an evaluation model of pharmaceutical services in high-risk municipalities of the Amazon region, focusing on indicators regarding organization of services and prescribing according to national guidelines.</p> <p>Methods</p> <p>A theoretical framework of pharmaceutical services for non-complicated malaria was built based on the Rapid Evaluation Method (WHO). The framework included organization of services and prescribing, among other activities. The study was carried out in 15 primary health facilities in six high-risk municipalities of the Brazilian Amazon. Malaria individuals ≥ 15 years old were approached and data was collected using specific instruments. Data was checked by independent reviewers and fed to a data bank through double-entry. Descriptive variables were analyzed.</p> <p>Results</p> <p>A copy of the official treatment guideline was found in 80% of the facilities; 67% presented an environment for receiving and prescribing patients. Re-supply of stocks followed a different timeline; no facilities adhered to forecasting methods for stock management. No shortages or expired anti-malarials were observed, but overstock was a common finding. On 86.7% of facilities, the average of good storage practices was 48%. Time between diagnosis and treatment was zero days. Of 601 patients interviewed, 453 were diagnosed for <it>Plasmodium vivax</it>; of these, 99.3% received indications for the first-line scheme. Different therapeutic schemes were given to <it>Plasmodium falciparum </it>patients. Twenty-eight (4.6%) out of 601 were prescribed regimens not listed in the national guideline. Only 5.7% individuals received a prescription or a written instruction of any kind.</p> <p>Conclusions</p> <p>The results show that while diagnostic procedure is well established and functioning in the Brazilian malaria programme, prescribing is still an activity that is actually not performed. The absence of physicians and poor integration between malaria services and primary health services make for the lack of a prescription or written instruction for malaria patients throughout the Brazilian Amazon. This fact may lead to a great number of problems in rational use and in adherence to medication.</p

Energy Dissipating Devices in Falling Rock Protection Barriers

Rockfall is a phenomenon which, when uncontrolled, may cause extensive material damage and personal injury. One of the structures used to avoid accidents caused by debris flows or rockfalls is flexible barriers. The energy dissipating devices which absorb the energy generated by rock impact and reduce the mechanical stresses in the rest of the elements of the structure are an essential part of these kinds of structures. This document proposes an overview of the performance of energy dissipating devices, as well as of the role that they fulfil in the barrier. Furthermore, a compilation and a description of the dissipating elements found in the literature are proposed. Additionally, an analysis has been performed of the aspects taken into account in the design, such as experimental (quasi-static and dynamic) tests observing the variation of the behaviour curve depending on the test speed and numerical simulations by means of several finite element software packages