304 research outputs found
The Positive and Negative Experiences of 342 Antidepressant Users
Most efficacy and safety studies about medications adopt a quantitative approach, testing specific hypotheses with restricted samples. This online survey provides additional insights by directly asking people open questions. Thematic analysis was used to explore the responses of 342 antidepressant users to “Is there anything else you would like to tell us about your experience of taking medication”. 59 (17.3%) made exclusively positive comments, 146 (42.7%) purely negative comments and 137 (40.0%) offered a mixture of positive and negative. Positive themes included: Daily Coping, Life-Changing/Saving and Stepping Stone. Negative themes included: Physical Adverse Effects, Emotional and Cognitive Blunting, and Withdrawal Effects. Many participants also commented on relationships with prescribers. Collaboration was particularly valued. Negative sub-themes included failings in relation to information (especially about adverse effects and withdrawal), support, and alternatives. Clinicians have a duty to inform potential antidepressant users about positive and adverse effects, including withdrawal effects
Assessment of 1991 NEHRP Provisions for Nonstructural Components and Recommended Revisions
As one part of the 1994 update effort of the 1991 NEHRP provisions, the seismic design force formulas for nonstructural components as they exist in the 1991 provisions are critically assessed and some of their shortcomings are identified. Various levels of improvements to these formulas are then presented which, on the one hand, preserve the equivalent lateral force format for design applicability and, on the other, correct some of the deficiencies on the basis of analyses, experimental results and observation data from past earthquakes.
Based on different interpretations of the component seismic coefficients as well as different degrees of simplicity required in practical design, three recommendations are proposed. The first recommended revision is the most comprehensive in that both effects of nonstructural component anchorage detailing and its supporting structural characteristics are taken into account. The second recommendation is a structure-driven type of modification of the current provisions and is motivated by the possibility that nonstructural component information during a design process is not available. The third revision, however, mainly concentrates on the effect of nonstructural component characteristics on the design force although it partially implies structural effects in the process of determining the response modification coefficient. The maximum and minimum design forces in the three recommendations are compared with those produced by the 1991 NEHRP provisions, the 1991 UBC, and the 1985 Tri-Service codes. Case studies of a parapet, a storage rack and a general equipment attached to a reinforced concrete shear wall structure are provided to show the relative conservatism involved in different codes and the importance of the factors ignored in the current provisions.
Simple displacement equations are also developed in this report to provide deformation information needed in some cases of practical design
Statistics of non-linear stochastic dynamical systems under L\'evy noises by a convolution quadrature approach
This paper describes a novel numerical approach to find the statistics of the
non-stationary response of scalar non-linear systems excited by L\'evy white
noises. The proposed numerical procedure relies on the introduction of an
integral transform of Wiener-Hopf type into the equation governing the
characteristic function. Once this equation is rewritten as partial
integro-differential equation, it is then solved by applying the method of
convolution quadrature originally proposed by Lubich, here extended to deal
with this particular integral transform. The proposed approach is relevant for
two reasons: 1) Statistics of systems with several different drift terms can be
handled in an efficient way, independently from the kind of white noise; 2) The
particular form of Wiener-Hopf integral transform and its numerical evaluation,
both introduced in this study, are generalizations of fractional
integro-differential operators of potential type and Gr\"unwald-Letnikov
fractional derivatives, respectively.Comment: 20 pages, 5 figure
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Characterizing the strength of wood truss joints
Probability density functions (normal, lognormal, and three-parameter Weibull) were used to characterize strength data for three different types of metal-plate-connected wood truss joints (web at the bottom chord, tension splice, and heel). Modulus of elasticity (MOE) of the lumber used to fabricate the joints was also characterized. A probability-plot technique, in conjunction with Kolmogorov-Smirnov and chi-square statistics, was used to determine which distribution best fit the data. Lumber MOE was best described by a lognormal distribution. No single distributional form fit the strength data for all three joint types with equal accuracy. Lumber MOE and joint strength were unrelated. Strength data for the web at the bottom chord and heel joints were best described by normal distributions; however, none of the distributions considered fit the data for the tension splice joints. The probability-plot technique provided a better visual inspection of fit than did a density function superimposed over a histogram. Fitted distributions are easy to work with and can be used in reliability analyses to simulate strength values of joints. The results presented here are for particular joint types and plates and should not be extrapolated to other truss joints
Karhunen-Loeve Representation of Periodic Second-Order Autoregressive Processes
Abstract. In dynamic data driven applications modeling accurately the uncertainty of various inputs is a key step of the process. In this paper, we first review the basics of the Karhunen-Loève decomposition as a means for representing stochastic inputs. Then, we derive explicit ex-pressions of one-dimensional covariance kernels associated with periodic spatial second-order autoregressive processes. We also construct numer-ically those kernels by employing the Karhunen-Loève expansion and making use of Fourier representation in order to solve efficiently the as-sociated eigenvalue problem. Convergence and accuracy of the numerical procedure are checked by comparing the covariance kernels obtained from the Karhunen-Loève expansions against theoretical solutions.
Fatty tissue within the maxillary sinus: a rare finding.
BACKGROUND: We report a rare case of fatty tissue within the maxillary sinus in a 21-years-old woman, with a history of several previous punctures of the maxillary sinus. CASE PRESENTATION: Clinical data of the patient was analysed retrospectively. The patient presented with symptoms of left-sided chronic maxillary sinusitis and had undergone several punctures of the left maxillary sinus 18 months earlier. Subsequent to one of the procedures an acute pain in the left orbit lasting a couple of days was noted. Left endoscopic transnasal antrotomy was performed. The maxillary sinus was filled with polypous, chronically inflamed mucous membrane. Upon its removal, the maxillary roof was identified as drawn downwards and covered with normal mucous membrane. Upon dissection of the membrane, adipose tissue filling the zygomatic recess of the sinus was identified and subsequently removed. The maxillary roof was unchanged. Histopatologic examination confirmed the material to be adipose tissue. No short or long term sequelae occurred. CONCLUSION: Adipose tissue can be found in the maxillary sinus most commonly when penetrating from surrounding locations. It is our hypothesis that in the reported patient it penetrated from the orbit to the maxillary sinus following puncture. It seems that a hole in the maxillary sinus roof, about 1 mm in diameter, caused by the needle, may have been a portal of entry for the adipose tissue into the maxillary sinus. The discussed case suggests particular care be taken in performing puncture of the maxillary sinus
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