11,380 research outputs found
The effective Hamiltonian in curved quantum waveguides under mild regularity assumptions
The Dirichlet Laplacian in a curved three-dimensional tube built along a
spatial (bounded or unbounded) curve is investigated in the limit when the
uniform cross-section of the tube diminishes. Both deformations due to bending
and twisting of the tube are considered. We show that the Laplacian converges
in a norm-resolvent sense to the well known one-dimensional Schroedinger
operator whose potential is expressed in terms of the curvature of the
reference curve, the twisting angle and a constant measuring the asymmetry of
the cross-section. Contrary to previous results, we allow the reference curves
to have non-continuous and possibly vanishing curvature. For such curves, the
distinguished Frenet frame standardly used to define the tube need not exist
and, moreover, the known approaches to prove the result for unbounded tubes do
not work. Our main ideas how to establish the norm-resolvent convergence under
the minimal regularity assumptions are to use an alternative frame defined by a
parallel transport along the curve and a refined smoothing of the curvature via
the Steklov approximation.Comment: 29 pages, 6 figure
Intravenous versus subcutaneous drug administration. Which do patients prefer? A systematic review
BACKGROUND:
Intravenous (IV) drug delivery is commonly used for its rapid administration and immediate drug effect. Most studies compare IV to subcutaneous (SC) delivery in terms of safety and efficacy, but little is known about what patients prefer.
METHODS:
A systematic review was conducted by searching seven electronic databases for articles published up to February 2014. Included studies were randomized controlled trials (RCTs) and/or crossover designs investigating patient preference for SC versus IV administration. The risk of bias in the RCTs was determined using the Cochrane Collaboration tool. Reviewers independently extracted data and assessed the risk of bias. Any discrepancies were resolved by consensus.
RESULTS:
The search identified 115 publications, but few (6/115) met the inclusion criteria. Patient populations and drugs investigated were diverse. Four of six studies demonstrated a clear patient preference for SC administration. Main factors associated with SC preference were time saving and the ability to have treatment at home. Only three studies used study-specific instruments to measure preference.
CONCLUSIONS:
Results suggest that patients prefer SC over IV delivery. Patient preference has clearly been neglected in clinical research, but it is important in medical decision making when choosing treatment methods as it has implications for adherence and quality of life. If the safety and efficacy of both administration routes are equivalent, then the most important factor should be patient preference as this will ensure optimal treatment adherence and ultimately improve patient experience or satisfaction. Future drug efficacy and safety studies should include contemporaneous, actual patient preference where possible, utilizing appropriate measures
ESTIMATION OF THE CYCLICAL COMPONENT OF ECONOMIC TIME SERIES
The objective of this paper is to show an alternative technique to smooth time series from Monte Carlo Simulations. The technique considers that time series can contain more than one structural break, coming from movements in coefficients of trend or from intercept. The Hodrick-Prescott Filter (HP) does not provide identification of such possible breaks in order to smooth trend from the series to analyze its cyclical component. If the series are relatively stable, this problem may not have relevant implications. Otherwise, for economies relatively unstable, trend movements may interfere in the specification of the cyclical component, and Hodrick-Prescott smoothing could lead empiricists to achieve simplistic forms to economic cycles. In the context, we present an empirical methodology that allows structural breaks in any point of time, from coefficients or from intercepts. We apply this recursive technique to different models with variations in trend, from coefficients and from intercepts, using series simulated by Monte Carlo. Moreover, we compare the results of both techniques to the Brazilian GDP.
Conflito socioambiental e recursos metodológicos da educação moral : preparando o professor para criar atividades de educação ambiental em perspectiva crítica
A partir de nossa tese de doutorado (Manzochi, 2008), discutimos aspectos de uma proposta de formação continuada de professores em Educação Ambiental (EA). Trata-se da criação de atividades para sala de aula, pelos educadores, utilizando a estratégia de aliar um caso de conflito socioambiental da sua realidade regional e os recursos metodológicos da Educação Moral propostos por Puig (1998b). A análise das atividades criadas aponta que a estratégia abre possibilidades para um trabalho de EA “formador de cidadania”, que permite, ao mesmo tempo, abordar questões do campo ambiental situadas na esfera pública (para além dos comportamentos individuais da vida privada) e desenvolver a moralidade dos sujeitos, na perspectiva de construção da personalidade moral (Puig, 1998a), exercitando suas capacidades morais e construindo criticamente significado para os guias de valor
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