869 research outputs found
Study protocol for a randomised controlled trial of Allen Carr's Easyway programme versus Lambeth and Southwark NHS for smoking cessation.
INTRODUCTION: Smoking is a major cause of ill health and is associated with several diseases including cancer, coronary heart disease and stroke. Many psychological and pharmacological smoking cessation treatments are available and although they are undoubtedly the most cost-effective health interventions available, many people still fail to maintain cessation in the longer term. Recently, National Institute for Health and Care Excellence called for comparative studies to determine the short-term and long-term effectiveness of Allen Carr's Easyway (ACE) method of stopping smoking. This study will compare the efficacy of the ACE programme and a 1-1 counselling service available via the National Health Service. METHODS AND ANALYSIS: A two-arm, parallel-group, blinded, randomised controlled trial will be conducted with people who smoke tobacco cigarettes, are aged ≥18 years and are motivated to quit. Exclusion criteria comprise self-reported mental health condition, pregnancy or respiratory disease such as chronic obstructive pulmonary disease or emphysema. The primary treatment outcome is smoking cessation 26 weeks after treatment. Participants will be analysed on an intention to treat basis at the point of randomisation. Before being randomised, the research team will not inform participants which two treatments are being compared. Once randomised researchers will be blinded to participant condition, and participants will be blinded to the condition they are not assigned to. Logistic regression will be used to estimate the effectiveness of the treatment condition on smoking cessation at 26 weeks. The following covariates will be included: baseline quit efficacy (at inclusion), age (at inclusion), gender and baseline nicotine dependency. ETHICS AND DISSEMINATION: Approval was granted by London-Fulham Research Ethics Committee (ref: 16/LO/1657). The study's findings will be published in peer-reviewed journals and disseminated at national and international conferences. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov identifier number: NCT02855255. ISRCTN registration number: ISRCTN23584477; Pre-results
Coded Merkle Tree: Solving Data Availability Attacks in Blockchains
In this paper, we propose coded Merkle tree (CMT), a novel hash accumulator
that offers a constant-cost protection against data availability attacks in
blockchains, even if the majority of the network nodes are malicious. A CMT is
constructed using a family of sparse erasure codes on each layer, and is
recovered by iteratively applying a peeling-decoding technique that enables a
compact proof for data availability attack on any layer. Our algorithm enables
any node to verify the full availability of any data block generated by the
system by just downloading a byte block hash commitment and
randomly sampling bytes, where is the size of the data
block. With the help of only one connected honest node in the system, our
method also allows any node to verify any tampering of the coded Merkle tree by
just downloading bytes. We provide a modular library for CMT
in Rust and Python and demonstrate its efficacy inside the Parity Bitcoin
client.Comment: To appear in Financial Cryptography and Data Security (FC) 202
An elliptically symmetric angular Gaussian distribution
We define a distribution on the unit sphere Sd−1 called the elliptically symmetric angular Gaussian distribution. This distribution, which to our knowledge has not been studied before, is a subfamily of the angular Gaussian distribution closely analogous to the Kent subfamily of the general Fisher–Bingham distribution. Like the Kent distribution, it has elliptical contours, enabling modelling of rotational asymmetry about the mean direction, but it has the additional advantages of being simple and fast to simulate from, and having a density and hence likelihood that is easy and very quick to compute exactly. These advantages are especially beneficial for computationally intensive statistical methods, one example of which is a parametric bootstrap procedure for inference for the directional mean that we describe
P-value based visualization of codon usage data
Two important and not yet solved problems in bacterial genome research are the identification of horizontally transferred genes and the prediction of gene expression levels. Both problems can be addressed by multivariate analysis of codon usage data. In particular dimensionality reduction methods for visualization of multivariate data have shown to be effective tools for codon usage analysis. We here propose a multidimensional scaling approach using a novel similarity measure for codon usage tables. Our probabilistic similarity measure is based on P-values derived from the well-known chi-square test for comparison of two distributions. Experimental results on four microbial genomes indicate that the new method is well-suited for the analysis of horizontal gene transfer and translational selection. As compared with the widely-used correspondence analysis, our method did not suffer from outlier sensitivity and showed a better clustering of putative alien genes in most cases
Masking effect of anti-androgens on androgenic activity in European river sediment unveiled by effect-directed analysis
This study shows that the androgen receptor agonistic potency is clearly concealed by the effects of androgen receptor antagonists in a total sediment extract, demonstrating that toxicity screening of total extracts is not enough to evaluate the full in vitro endocrine disrupting potential of a complex chemical mixture, as encountered in the environment. The anti-androgenic compounds were masking the activity of androgenic compounds in the extract with relatively high anti-androgenic potency, equivalent to 200 nmol flutamide equivalents/g dry weight. A two-step serial liquid chromatography fractionation of the extract successfully separated anti-androgenic compounds from androgenic compounds, resulting in a total androgenic potency of 3,820 pmol dihydrotestosterone equivalents/g dry weight. The fractionation simplified the chemical identification analysis of the original complex sample matrix. Seventeen chemical structures were tentatively identified. Polyaromatic hydrocarbons, a technical mixture of nonylphenol and dibutyl phthalate were identified to contribute to the anti-androgenic potency observed in the river sediment sample. With the GC/MS screening method applied here, no compounds with AR agonistic disrupting potencies could be identified. Seventy-one unidentified peaks, which represent potentially new endocrine disrupters, have been added to a database for future investigation
Teste de Morisky-Green e Brief Medication Questionnaire para avaliar adesão a medicamentos
OBJETIVO: Analisar a confiabilidade e o desempenho da versão em português de instrumentos de avaliação da adesão ao tratamento anti-hipertensivo. MÉTODOS: Pacientes hipertensos atendidos de janeiro a setembro de 2010 em uma unidade de atenção primária em Porto Alegre, RS, foram selecionados aleatoriamente (n = 206). Na avaliação da adesão foram utilizadas versões em português do Teste de Morisky-Green (TMG) e do Brief Medication Questionnaire (BMQ). Foram analisados consistência interna, estabilidade temporal e desempenho com relação a três padrões-ouro: controle inadequado da pressão arterial (> 140/90 mmHg); taxa insuficiente de retirada de medicação na farmácia da Unidade Básica de Saúde (< 80%); e a combinação de ambos. RESULTADOS: Dos pacientes avaliados, 97 utilizavam medicamentos dispensados somente pela farmácia da Unidade Básica de Saúde. Os testes apresentaram boa consistência interna: BMQ α de Cronbach de 0,66 (IC95% 0,60;0,73) e o TMG 0,73 (IC95% 0,67;0,79). O desempenho do BMQ no domínio regime apresentou sensibilidade de 77%, especificidade de 58% e área sob a curva ROC de 0,70 (IC95% 0,55;0,86), e o TMG sensibilidade de 61%, especificidade de 36% e área sob a curva ROC de 0,46 (IC95% 0,30;0,62). A correlação entre o BMQ e o TMG foi de r = 0,28, p > 0,001. A baixa adesão ao BMQ está associada a maiores níveis tensionais quando comparada com pacientes aderentes (148,4 [dp 20,1] vs 128,8 [dp 17,8], p < 0,001), mas não para o TMG. CONCLUSÕES: O BMQ apresentou melhor desempenho que o TMG, com maiores sensibilidade e especificidade. A avaliação da adesão pode auxiliar o clinico na discriminação entre uso inadequado da medicação e esquema terapêutico insuficiente.OBJETIVO: Analizar la confiabilidad y el desempeño de la versión en portugués de instrumentos de evaluación de la adherencia al tratamiento antihipertensivo. MÉTODOS: Pacientes hipertensos atendidos de enero a septiembre de 2010 en una unidad de atención primaria en Porto Alegre, Sur de Brasil, fueron seleccionados aleatoriamente (n=206). En la evaluación de la adherencia fueron utilizadas versiones en portugués de la Prueba de Morisky-Green (TMG) y del Brief Medication Questionnarie (BMQ). Se analizaron consistencia interna, estabilidad temporal y desempeño con relación a tres patrones-oro: control inadecuado de la presión arterial (> 140/90 mmHg); tasa insuficiente de retirada de medicación en la farmacia de la Unidad Básica de Salud (< 80%) y la combinación de ambos. RESULTADOS: De los pacientes evaluados, 97 utilizaban medicamentos dispensados solamente por la farmacia de la Unidad Básica de Salud. Las pruebas presentaron buena consistencia interna: BMQ α de Cronbach de 0,66 (IC95% 0,60;0,73) y el TMG 0,73 (IC95% 0,67;0,79). El desempeño del BMQ en el dominio régimen presentó sensibilidad de 77%, especificidad de 58%, y área bajo la curva ROC de 0,70 (IC95% 0,55;0,86) y el TMG sensibilidad de 61%, especificidad de 36% y área bajo la curva ROC de 0,46 (IC95% 0,30;0,62). La correlación entre el BMQ y el TMG fue de r=0,28, p>0,001. La baja adherencia al BMQ está asociada a mayores niveles tensionales al compararlo con pacientes adherentes 148,4 [de 0,1] vs 128,8 [de 17,8], pOBJECTIVE: To analyze the reliability and performance of the Portuguese version of questionnaires used to evaluate adherence to hypertensive treatment. METHODS: Hypertensive patients attending a primary healthcare unit in Porto Alegre, Southern Brazil, from January to September 2010, were randomly selected (n = 206). To evaluate adherence, Portuguese versions of the Morisky-Green test (MGT) and the Brief Medication Questionnaire (BMQ) were used. The analysis considered internal consistency, temporal stability and performance compared to three gold standards, which are: inadequate control of blood pressure (BP > 140/90 mmHg); insufficient rate of medication acquisition at the institution's pharmacy
Observation of an Exotic Baryon in Exclusive Photoproduction from the Deuteron
In an exclusive measurement of the reaction , a
narrow peak that can be attributed to an exotic baryon with strangeness
is seen in the invariant mass spectrum. The peak is at
GeV/c with a measured width of 0.021 GeV/c FWHM, which is largely
determined by experimental mass resolution. The statistical significance of the
peak is . The mass and width of the observed peak are
consistent with recent reports of a narrow baryon by other experimental
groups.Comment: 5 pages, 5 figure
Measurement of Beam-Spin Asymmetries for Deep Inelastic Electroproduction
We report the first evidence for a non-zero beam-spin azimuthal asymmetry in
the electroproduction of positive pions in the deep-inelastic region. Data have
been obtained using a polarized electron beam of 4.3 GeV with the CLAS detector
at the Thomas Jefferson National Accelerator Facility (JLab). The amplitude of
the modulation increases with the momentum of the pion relative to
the virtual photon, , with an average amplitude of for range.Comment: 5 pages, RevTEX4, 3 figures, 2 table
Measurement of the Polarized Structure Function for in the Resonance Region
The polarized longitudinal-transverse structure function
has been measured in the resonance region at and 0.65
GeV. Data for the reaction were taken at Jefferson Lab
with the CEBAF Large Acceptance Spectrometer (CLAS) using longitudinally
polarized electrons at an energy of 1.515 GeV. For the first time a complete
angular distribution was measured, permitting the separation of different
non-resonant amplitudes using a partial wave analysis. Comparison with previous
beam asymmetry measurements at MAMI indicate a deviation from the predicted
dependence of using recent phenomenological
models.Comment: 5 pages, LaTex, 4 eps figures: to be published in PRC/Rapid
Communications. Version 2 has revised Q^2 analysi
Two-Nucleon Momentum Distributions Measured in 3He(e,e'pp)n
We have measured the 3He(e,e'pp)n reaction at 2.2 GeV over a wide kinematic
range. The kinetic energy distribution for `fast' nucleons (p > 250 MeV/c)
peaks where two nucleons each have 20% or less, and the third nucleon has most
of the transferred energy. These fast pp and pn pairs are back-to-back with
little momentum along the three-momentum transfer, indicating that they are
spectators. Experimental and theoretical evidence indicates that we have
measured distorted two-nucleon momentum distributions by striking the third
nucleon and detecting the spectator correlated pair.Comment: 6 pages, 5 figures, submitted to PR
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