11 research outputs found

    Modeling of Electromagnetic Waves in Media with Dirac Distribution of Electric Properties

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    Measuring soil hydraulic properties after clearing of tropical rain forest in a Costa Rican soil.

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    The crust test and a desorption method using undisturbed samples placed in porous cups were applied to measure hydraulic conductivity (K) and moisture retention data in a Humoxic Tropohumult. The crust test measures infiltration rates through a series of man-made crusts with different resistances and subcrust pressure heads. Total porosities were not different but the forest topsoil contained more continuous macropores in the form of compound packing voids while the pasture soil contained less continuous accommodated planar voids. -from Authors</p

    Neurocognitive effects after brief pulse and ultrabrief pulse unilateral electroconvulsive therapy for major depression: A review

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    Background: Neurocognitive functioning is well known to be affected after ECT. However quantified data about the severity of the cognitive impairment after ultrabrief pulse and brief pulse ECT are limited, which makes it hard to judge its clinical relevance. Methods: To review all prospective studies using right unilateral (ultra) brief pulse index electroconvulsive therapy published up until February 2011 which used at least one instrument for cognitive assessment before and after ECT. The severity and persistence of neurocognitive side effects immediately (one to seven days post ECT), between one and six months and after six months post ECT were assessed by calculating effect sizes using Cohen's d. Results: Ten studies fulfilled the inclusion criteria and provided detailed information to compute effect sizes. The results indicate loss of autobiographical memory and impairment of verbal fluency, anterograde verbal and non-verbal memory immediately after brief pulse RUL ECT. To a lesser extent impairment of working memory and reduced speed of processing is found. Autobiographical memory is the only domain still being impaired between one and six months post ECT, but improved in this period. Verbal fluency normalized to baseline performance between one and six months post ECT whereas anterograde verbal and non-verbal memory normalized or even improved. Speed of processing improved within six months after ECT. Long-term data on these cognitive domains were not available. Based on two of the ten included studies the results suggest that ultrabrief pulse RUL ECT causes less decline in autobiographical and anterograde memory after ECT than brief pulse RUL ECT. Limitations: This review may be limited because of the small number of included studies and due to unreliable effect sizes. Furthermore, few data were available for non-memory domains and cognitive functioning after six months. Conclusions: Loss of autobiographical memory is still present between one and six months after unilateral brief pulse ECT. Ultrabrief pulse RUL ECT shows less decline in autobiographical memory. Other neurocognitive impairments after brief pulse RUL ECT seem to be transient. © 2012 Elsevier B.V. All rights reserved

    Short- and long-term neurocognitive functioning after electroconvulsive therapy in depressed elderly: a prospective naturalistic study

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    Background: It is generally assumed that the elderly patients are more vulnerable to cognitive side effects after electroconvulsive therapy (ECT) than younger depressed patients. The current study aims to evaluate the nature and extent of changes across multiple domains of neurocognitive functioning in a group of elderly depressed patients after ECT. Methods: In this prospective naturalistic study, we included 42 depressed patients aged ≥55 years. Global cognitive function, memory, and executive function were assessed before ECT treatment and within one week (short-term post-ECT) and six months after ECT (long-term post-ECT). Associations between cognitive functioning and electrode placement, total number of treatment sessions, age, and the severity of depression at the time of cognitive measurement were studied. Results: Our data offered no evidence of decline for any of the neurocognitive tests after ECT, given its power to detect the difference. Post-ECT improvement of neurocognitive functioning was statistically significant for the Mini-Mental State Examination, Visual Association Test, 10 Words Verbal Learning Test, and Expanded Mental Control Test. Effect sizes were medium to large. After six months, compared with post-ECT performance, statistically significant improvement was found only for the Trail Making Test-A and the Letter Fluency Test with small to medium effect sizes. Conclusions: In our severely depressed elderly patients, neurocognitive performance improved or did not change after ECT. Patients with poor cognitive function were not able to participate in neuropsychological assessment before ECT started. Consequently these results may not apply to patients with more severe cognitive impairment prior to the start of ECT. Copyright © International Psychogeriatric Association 2013

    Relapse and long-term cognitive performance after brief pulse or ultrabrief pulse right unilateral electroconvulsive therapy: A multicenter naturalistic follow up

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    Background Superior cognitive functioning for electroconvulsive therapy (ECT) with right unilateral (RUL) ultrabrief pulse (UBP) stimulation compared to RUL brief pulse (BP) stimulation is not clearly established and long-term data is needed. Methods We conducted a prospective naturalistic follow-up of 87 inpatients from three tertiary psychiatric hospitals. Before these patients entered the follow up phase, they had participated in a RCT comparing twice weekly RUL BP (1.0 ms) with RUL UBP (0.3-0.4 ms) ECT eight times seizure threshold until remission (MADRS<10), for a maximum of six weeks. Three and six months after the index ECT patients were monitored for relapse and cognitive performance (retrograde amnesia, semantic memory and lexical memory). We compared relapse rate and cognitive performance between RUL BP and RUL UBP stimulation. Results Of the 50 patients who remitted after index ECT 44 (24 BP; 20 UBP) were monitored for follow up. Relapse occurred in 25% of the BP group and in 25% of the UBP group (χ2=0.00, p=1.0) at three-month follow-up; whereas 43.5% of the BP group and 35% of the UBP group relapsed (χ2=0.322, p=0.57) at six months follow-up. Cognitive assessments (17 BP; 16 UBP) showed no significant differences between BP and UBP groups, except for an advantage for the BP group in the autobiographical incident questions at three months follow-up only (p=0.04; d=0.77). Limitations This study may be limited since relapse in a naturalistic follow-up can be influenced by medication and other unknown factors, like social support, medical comorbidity, and psychotherapy. The small numbers of our subgroups hamper statistical significance. Conclusions Patients that achieved remission after RUL BP or RUL UBP ECT showed similar relapse rates after three and six months. There was no cognitive advantage of UBP over BP ECT in follow up. Clinical trials registration Netherlands trial register www.trialregister.nl registration number NTR1304

    Efficacy and cognitive side effects after brief pulse and ultrabrief pulse right unilateral electroconvulsive therapy for major depression: a randomized, double-blind, controlled study

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    Objective: To compare the efficacy and cognitive side effects of high-dose unilateral brief pulse electroconvulsive therapy (ECT) with those of high-dose unilateral ultrabrief pulse ECT in the treatment of major depression. Method: From April 2007 until March 2011, we conducted a prospective, double-blind, randomized multicenter trial in 3 tertiary psychiatric hospitals. All patients with a depressive disorder according to DSM-IV criteria were eligible. Depression severity was assessed with the Montgomery-Asberg Depression Rating Scale; primary efficacy outcomes were response, defined as a score decrease ≥ 60% from baseline, and remission, defined as a score<10 at 2 consecutive weekly assessments. Total scores on the Autobiographical Memory Interview and Amsterdam Media Questionnaire were the primary outcome measures for retrograde amnesia. Other cognitive domains included category fluency (semantic memory) and letter fluency (lexical memory). Patients received twiceweekly unilateral brief pulse (1.0 millisecond) or ultrabrief pulse (0.3-0.4 millisecond) ECT 8 times seizure threshold until remission, for a maximum of 6 weeks. Results: Of the 116 patients, 75% (n = 87) completed the study. Among completers, 68.4% (26/58) of those in the brief pulse group achieved remission versus 49.0% (24/49) of those in the ultrabrief pulse group (P = .019), and the brief pulse group needed fewer treatment sessions to achieve remission: mean (SD) of 7.1 (2.6) versus 9.2 (2.3) sessions (P = .008). No significant group differences were found in the evaluation of the cognitive assessments. Conclusions: The efficacy and speed of remission seen with high-dose brief pulse right unilateral ECT twice weekly were superior to those seen with high-dose ultrabrief pulse right unilateral ECT, with equal cognitive side effects as defined by retrograde amnesia, semantic memory, and lexical memory. © Copyright 2013 Physicians Postgraduate Press, Inc

    Desempenho de diferentes guias de ondas para uso com o analisador de umidade TRASE Performance of different waveguides for use with the TRASE water content analyser

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    O trabalho teve como objetivo avaliar a relação entre a umidade e a constante dielétrica aparente do solo e diferentes guias de onda para uso com o analisador de umidade Trase, que opera de acordo com o princípio da reflectometria no domínio do tempo - TDR. Amostras indeformadas e deformadas de duas manchas de textura diferente de um Latossolo Amarelo Distrófico foram retiradas do campo e acondicionadas em recipientes de 10 L, perfazendo quatro repetições para cada textura e estrutura. Foram construídas três diferentes guias de onda, com hastes de 0,15 m, sendo uma com capacitor e uma sem capacitor no início da guia, com espaçamento de 0,009 m entre hastes e outra sem capacitor, com espaçamento de 0,022 m entre hastes. Essas guias de onda, juntamente com guias originais do fabricante com hastes de 0,20 m, espaçadas 0,022 m, foram inseridas individualmente em cada recipiente. Dados de umidade obtidos gravimetricamente e pelo analisador TRASE, e da constante dielétrica, foram tomados usando-se todas as guias de onda em cada recipiente durante a secagem do solo, de 0,35 m³ m-3 a 0,10 m³ m-3. Três modelos matemáticos foram ajustados aos dados de umidade e da correspondente constante dielétrica do solo gerados pelas guias de onda do fabricante. Um modelo exponencial foi considerado como mais adequado para estimativas dos teores de água, em função da constante dielétrica para a guia de onda do fabricante. Todas as guias de onda avaliadas apresentam viabilidade de uso, desde que previamente calibradas.<br>The objective of this work was to evaluate the relations between soil water content and the soil bulk dielectric constant, and to study different waveguides of a TRASE soil water content analyzer that operates according to TDR principles. Non-destructive and destructive samples of two sites of different texture of a Dystrophic Yellow Latossol were collected and packed into 10 L containers, resulting in four replications for each texture and structure. Three different waveguides were built with rods of 0.15 m length, one with a capacitor at the beginning of the waveguide, one without a capacitor, with rods 0.009 m apart, and another without a capacitor, with rods 0.022 m apart. These waveguides, together with buriable standard ones supplied by tne manufactures with 0.20 m rods 0.022 m apart, were inserted in each sample. Soil water content was obtained by gravimetry and estimated by the TRASE analyzer, based on soil bulk dielectric constants using all waveguides during the soil drying process with water contents changing from 0.35 m³ m-3 to 0.10 m³ m-3. Three mathematical models were fitted to soil water content and bulk dielectric constant data. An exponential model was the most suitable in estimating soil water content as a function of bulk dielectric constant for the standard waveguide. All evaluated waveguides were feasible for use as long as they are previously calibrated
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