926 resultados para controlled active front end rectifier
Resumo:
Objective: To evaluate CBTp delivered by non-expert therapists, using CBT relevant measures. Methods: Participants (N=74) were randomised into immediate therapy or waiting list control groups. The therapy group was offered six months of therapy and followed up three months later. The waiting list group received therapy after waiting nine months (becoming the delayed therapy group). Results: Depression improved in the combined therapy group at both the end of therapy and follow-up. Other significant effects were found in only one of the two therapy groups (positive symptoms; cognitive flexibility; uncontrollability of thoughts) or one of the two timepoints (end of therapy: PANSS general symptoms, anxiety, suicidal ideation, social functioning, resistance to voices; follow-up: power beliefs about voices, negative symptoms). There was no difference in costs between the groups. Conclusions: The only robust improvement was in depression. Nevertheless, there were further encouraging but modest improvements in both emotional and cognitive variables, in addition to psychotic symptoms.
Resumo:
This experiment addresses the long-term effect of active immunization of goats against a recombinant ovine inhibin alpha subunit (roIHN-alpha). In late anestrus 100 mu g of roINH-alpha was administered to 40 pluriparous Boer goat does, followed, 4 weeks later, by a booster injection. Weekly blood samples were drawn to monitor the inhibin binding capacity with the aid of a radio-tracer binding assay. From the onset until 48 h after the end of each estrus, follicular development and ovulation rate were monitored at 24 h intervals by transrectal ultrasonography. Beginning in August and continuing into January, does were mated at every other estrus, and submitted to transcervical embryo collection. Seven months after the first immunization, the does were mated again and permitted to carry to term. All immunized does produced inhibin antibodies, an elevated titre being first detected 2 weeks after primary immunization. Maximum titres were reached after 6 weeks, i.e. 2 weeks after the booster injection. Thereafter, in the course of the following 32 weeks, the titre subsided gradually. The does started cycling by mid-August. At that stage the average number of follicles more than 4 mm in diameter, ovulations and total embryos and ova recovered were 14.7 (+/- 2.3), 5.3 (+/- 0.7) and 4.4 (+/- 1.0), respectively. A steady decline followed and in January the corresponding means were: 5.2 (+/- 0.6) follicles, 3.1 (+/- 0.6) ovulations and 1.2 (+/- 0.4) embryos and ova recovered. When mated toward the end of the breeding season, 85% of the does became pregnant to the first mating and 73% went to term. Healthy kids were born, the average litter size being 2.2 (+/- 0.1). In conclusion, immunization of goats against a recombinant inhibin alpha-subunit proved to be a practicable means of producing embryos for transfer purposes. After about half a year, when the inhibin antibody titre has subsided, it is possible to return the does to the breeding flock without risking complications with normal breeding activity. (c) 2009 Elsevier Inc. All rights reserved.
Resumo:
[(VO)-O-IV(acac)(2)] reacts with an equimolar amount of benzoyl hydrazones of 2-hydroxyacetophenone (H2L1), 2-hydroxy-5-methylacetophenone (H2L2) and 5-chloro-2-hydroxyacetophenone (H2L4) in methanol to afford the penta-coordinated mixed-ligand methoxy bonded oxidovanadium(V) complexes [(VO)-O-V(L-1)-(OCHA(3))](1). [(VO)-O-V(L-2)(OCH3)](2), and [(VO)-O-V(L-4)(OCH3)](4), respectively, whereas, the similar reaction with the benzoyl hydrazone of 2-hydroxy-5-methoxyacetophenone (H2L3) producing only the hexa-coordinated dimethoxy-bridged dimeric complex [(VO)-O-V(L-3)(OCH3)](2) (3A). Similar type of hexa-coordinated dimeric analogue of 1 i.e., [(VO)-O-V(L-1)(OCH3)](2) (1A) was obtained from the reaction of [(VO)-O-IV(acac)(2)] with the equimolar amount of H2L1 in presence of half equivalent 4,4'-bipyridine in methanol while the decomposition of [(VO)-O-IV(L-2)(bipy)] complex in methanol afforded the dimeric analogue of 2 i.e., [(VO)-O-V(L-2)(OCH3)](2) (2A). All these dimeric complexes 1A-3A react with an excess amount of imidazole in methanol producing the respective monomeric complex. The X-ray structural analysis of 1-3 and their dimeric analogues 1A-3A indicates that the geometry around the vanadium center in the monomeric form is distorted square-pyramidal while that of their respective dimeric forms is distorted octahedral, where the ligands are bonded to vanadium meridionally in their fully deprotonated enol forms. Due to the formation of bridge, the V-O(methoxy) bond in the dimeric complexes is lengthened to such an extent that it becomes equal in length with the V-O(phenolate) bond in 3A and even longer in 1A and 2A, which is unprecedented. The H-1 NMR spectra of the complexes 1A-3A in CDCl3 solution, indicates that these dimeric complexes are converted appreciably into their respective monomeric form. Complexes are electro-active displaying one quasi-reversible reduction peak near +0.25 V versus SCE in CH2Cl2 solution. The E-1/2 values of the complexes show linear relationship with the Hammett parameter (sigma) of the substituents. All these VO3+-complexes are converted to the corresponding complexes with V2O34+ motif simply on refluxing them in acetone and to the complexes with VO2+ motif on reaction with 2 KOH in methanol. (C) 2008 Elsevier Ltd. All rights reserved.
Resumo:
Aim. The aim of this study was to investigate whether a single soccer specific fitness test (SSFT) could differentiate between highly trained and recreationally active soccer players in selected test performance indicators. Methods. Subjects: 13 Academy Scholars (AS) from a professional soccer club and 10 Recreational Players (RP) agreed to participate in this study. Test 1-(V)over dotO(2) max was estimated from a progressive shuttle run test to exhaustion. Test 2-The SSFT was controlled by an automated procedure and alternated between walking, sprinting, jogging and cruise running speeds. Three activity blocks (1A, 2A and 3A) were separated by 3 min rest periods in which blood lactate samples were drawn. The 3 blocks of activity (Part A) were followed by 10 min of exercise at speeds alternating between jogging and cruise running (Part B). Results. Estimated (V)over dotO(2) max did not significantly differ between groups, although a trend for a higher aerobic capacity was evident in AS (p<0.09). Exercising heart rates did not differ between AS and RP, however, recovery heart rates taken from the 3 min rest periods were significantly lower in AS compared with RP following blocks 1A (124.65 b(.)min(-1) +/-7.73 and 133.98 b(.)min(-1) +/-6.63), (p<0.05) and 3A (129.91 b.min(-1) +/-10.21 and 138.85 b.min(-1) +/-8.70), (p<0.01). Blood lactate concentrations were significantly elevated in AS in comparison to RP following blocks 2A (6.91 mmol(.)l(-1) +/-2.67 and 4.74 mmol(.)l(-1) +/-1.28) and 3A (7.18 mmol(.)l(-1) +/-2.97 and 4.88 mmol(.)l(-1) +/-1.50), (p<0.05). AS sustained significantly faster average sprint times in block 3A compared with RP (3.18 sec +/-0.12 and 3.31 sec +/-0.12), (p<0.05). Conclusion. The results of this study show that highly trained soccer players are able to sustain, and more quickly recover from, high intensity intermittent exercise.
Resumo:
Background: Osteoarthritis (OA) of the knee is the most prevalent joint disorder. Previous studies suggest that bromelain, a pineapple extract, may be a safer alternative/adjunctive treatment for knee OA than current conventional treatment. Aim: To assess the efficacy of bromelain in treating OA of the knee. Design: Randomized, double-blind placebo-controlled trial. Methods: Subjects (n=47) with a confirmed diagnosis of moderate to severe knee OA were randomized to 12 weeks of bromelain 800 mg/day or placebo, with a 4-week follow-up. Knee (pain, stiffness and function) and quality-of-life symptoms were reported monthly in the WOMAC and SF36 questionnaires, respectively. Adverse events were also recorded. The primary outcome measure was the change in total WOMAC score from baseline to the end of treatment at week 12. Longitudinal models were used to evaluate outcome. Results: Thirty-one patients completed the trial (14 bromelain, 17 placebo). No statistically significant differences were observed between groups for the primary outcome (coefficient 11.16, p=0.27, 95%CI-8.86 to 31.18), nor the WOMAC subscales or SF36. Both treatment groups showed clinically relevant improvement in the WOMAC disability subscale only. Adverse events were generally mild in nature. Discussion: This study suggests that bromelain is not efficacious as an adjunctive treatment of moderate to severe OA, but its limitations support the need for a follow-up study.
Resumo:
Rationale: Liking, cravings and addiction for chocolate ("chocoholism") are often explained through the presence of pharmacologically active compounds. However, mere "presence" does not guarantee psycho-activity. Objectives: Two double-blind, placebo-controlled studies measured the effects on cognitive performance and mood of the amounts of cocoa powder and methylxanthines found in a 50 g bar of dark chocolate. Methods: In study 1, participants (n=20) completed a test battery once before and twice after treatment administration. Treatments included 11.6 g cocoa powder and a caffeine and theobromine combination (19 and 250 mg, respectively). Study 2 (n=22) comprised three post-treatment test batteries and investigated the effects of "milk" and "dark" chocolate levels of these methylxanthines. The test battery consisted of a long duration simple reaction time task, a rapid visual information processing task, and a mood questionnaire. Results: Identical improvements on the mood construct "energetic arousal" and cognitive function were found for cocoa powder and the caffeine+theobromine combination versus placebo. In chocolate, both "milk chocolate" and "dark chocolate" methylxanthine doses improved cognitive function compared with "white chocolate". The effects of white chocolate did not differ significantly from those of water. Conclusion: A normal portion of chocolate exhibits psychopharmacological activity. The identical profile of effects exerted by cocoa powder and its methylxanthine constituents shows this activity to be confined to the combination of caffeine and theobromine. Methylxanthines may contribute to the popularity of chocolate; however, other attributes are probably much more important in determining chocolate's special appeal and in explaining related self-reports of chocolate cravings and "chocoholism".
Resumo:
Researchers in the rehabilitation engineering community have been designing and developing a variety of passive/active devices to help persons with limited upper extremity function to perform essential daily manipulations. Devices range from low-end tools such as head/mouth sticks to sophisticated robots using vision and speech input. While almost all of the high-end equipment developed to date relies on visual feedback alone to guide the user providing no tactile or proprioceptive cues, the “low-tech” head/mouth sticks deliver better “feel” because of the inherent force feedback through physical contact with the user's body. However, the disadvantage of a conventional head/mouth stick is that it can only function in a limited workspace and the performance is limited by the user's strength. It therefore seems reasonable to attempt to develop a system that exploits the advantages of the two approaches: the power and flexibility of robotic systems with the sensory feedback of a headstick. The system presented in this paper reflects the design philosophy stated above. This system contains a pair of master-slave robots with the master being operated by the user's head and the slave acting as a telestick. Described in this paper are the design, control strategies, implementation and performance evaluation of the head-controlled force-reflecting telestick system.
Resumo:
Retinal blurring resulting from the human eye's depth of focus has been shown to assist visual perception. Infinite focal depth within stereoscopically displayed virtual environments may cause undesirable effects, for instance, objects positioned at a distance in front of or behind the observer's fixation point will be perceived in sharp focus with large disparities thereby causing diplopia. Although published research on incorporation of synthetically generated Depth of Field (DoF) suggests that this might act as an enhancement to perceived image quality, no quantitative testimonies of perceptional performance gains exist. This may be due to the difficulty of dynamic generation of synthetic DoF where focal distance is actively linked to fixation distance. In this paper, such a system is described. A desktop stereographic display is used to project a virtual scene in which synthetically generated DoF is actively controlled from vergence-derived distance. A performance evaluation experiment on this system which involved subjects carrying out observations in a spatially complex virtual environment was undertaken. The virtual environment consisted of components interconnected by pipes on a distractive background. The subject was tasked with making an observation based on the connectivity of the components. The effects of focal depth variation in static and actively controlled focal distance conditions were investigated. The results and analysis are presented which show that performance gains may be achieved by addition of synthetic DoF. The merits of the application of synthetic DoF are discussed.
Resumo:
The objective of a Visual Telepresence System is to provide the operator with a high fidelity image from a remote stereo camera pair linked to a pan/tilt device such that the operator may reorient the camera position by use of head movement. Systems such as these which utilise virtual reality style helmet mounted displays have a number of limitations. The geometry of the camera positions and of the displays is generally fixed and is most suitable only for viewing elements of a scene at a particular distance. To address such limitations, a prototype system has been developed where the geometry of the displays and cameras is dynamically controlled by the eye movement of the operator. This paper explores why it is necessary to actively adjust the display system as well as the cameras and justifies the use of mechanical adjustment of the displays as an alternative to adjustment by electronic or image processing methods. The electronic and mechanical design is described including optical arrangements and control algorithms. The performance and accuracy of the system is assessed with respect to eye movement.
Resumo:
People with disabilities such as quadriplegia can use mouth-sticks and head-sticks as extension devices to perform desired manipulations. These extensions provide extended proprioception which allows users to directly feel forces and other perceptual cues such as texture present at the tip of the mouth-stick. Such devices are effective for two principle reasons: because of their close contact with the user's tactile and proprioceptive sensing abilities; and because they tend to be lightweight and very stiff, and can thus convey tactile and kinesthetic information with high-bandwidth. Unfortunately, traditional mouth-sticks and head-sticks are limited in workspace and in the mechanical power that can be transferred because of user mobility and strength limitations. We describe an alternative implementation of the head-stick device using the idea of a virtual head-stick: a head-controlled bilateral force-reflecting telerobot. In this system the end-effector of the slave robot moves as if it were at the tip of an imaginary extension of the user's head. The design goal is for the system is to have the same intuitive operation and extended proprioception as a regular mouth-stick effector but with augmentation of workspace volume and mechanical power. The input is through a specially modified six DOF master robot (a PerForceTM hand-controller) whose joints can be back-driven to apply forces at the user's head. The manipulation tasks in the environment are performed by a six degree-of-freedom slave robot (the Zebra-ZEROTM) with a built-in force sensor. We describe the prototype hardware/software implementation of the system, control system design, safety/disability issues, and initial evaluation tasks.
Resumo:
Visual Telepresence system which utilize virtual reality style helmet mounted displays have a number of limitations. The geometry of the camera positions and of the display is fixed and is most suitable only for viewing elements of a scene at a particular distance. In such a system, the operator's ability to gaze around without use of head movement is severely limited. A trade off must be made between a poor viewing resolution or a narrow width of viewing field. To address these limitations a prototype system where the geometry of the displays and cameras is dynamically controlled by the eye movement of the operator has been developed. This paper explores the reasons why is necessary to actively adjust both the display system and the cameras and furthermore justifies the use of mechanical adjustment of the displays as an alternative to adjustment by electronic or image processing methods. The electronic and mechanical design is described including optical arrangements and control algorithms, An assessment of the performance of the system against a fixed camera/display system when operators are assigned basic tasks involving depth and distance/size perception. The sensitivity to variations in transient performance of the display and camera vergence is also assessed.
Resumo:
BACKGROUND: Prebiotics are food ingredients, usually non-digestible oligosaccharides, that are selectively fermented by populations of beneficial gut bacteria. Endoxylanases, altering the naturally present cereal arabinoxylans, are commonly used in the bread industry to improve dough and bread characteristics. Recently, an in situ method has been developed to produce arabinoxylan-oligosaccharides (AXOS) at high levels in breads through the use of a thermophilic endoxylanase. AXOS have demonstrated potentially prebiotic properties in that they have been observed to lead to beneficial shifts in the microbiota in vitro and in murine, poultry and human studies. METHODS: A double-blind, placebo controlled human intervention study was undertaken with 40 healthy adult volunteers to assess the impact of consumption of breads with in situ produced AXOS (containing 2.2 g AXOS) compared to non-endoxylanase treated breads. Volatile fatty acid concentrations in faeces were assessed and fluorescence in situ hybridisation was used to assess changes in gut microbial groups. Secretory immunoglobulin A (sIgA) levels in saliva were also measured. RESULTS: Consumption of AXOS-enriched breads led to increased faecal butyrate and a trend for reduced iso-valerate and fatty acids associated with protein fermentation. Faecal levels of bifidobacteria increased following initial control breads and remained elevated throughout the study. Lactobacilli levels were elevated following both placebo and AXOS-breads. No changes in salivary secretory IgA levels were observed during the study. Furthermore, no adverse effects on gastrointestinal symptoms were reported during AXOS-bread intake. CONCLUSIONS: AXOS-breads led to a potentially beneficial shift in fermentation end products and are well tolerated.
Resumo:
Background and Objectives Low self-esteem (LSE) is associated with psychiatric disorder, and is distressing and debilitating in its own right. Hence, it is frequent target for treatment in cognitive behavioural interventions, yet it has rarely been the primary focus for intervention. This paper reports on a preliminary randomized controlled trial of cognitive behaviour therapy (CBT) for LSE using Fennell’s (1997) cognitive conceptualisation and transdiagnostic treatment approach ( [Fennell, 1997] and [Fennell, 1999]). Methods Twenty-two participants were randomly allocated to either immediate treatment (IT) (n = 11) or to a waitlist condition (WL) (n = 11). Treatment consisted of 10 sessions of individual CBT accompanied by workbooks. Participants allocated to the WL condition received the CBT intervention once the waitlist period was completed and all participants were followed up 11 weeks after completing CBT. Results The IT group showed significantly better functioning than the WL group on measures of LSE, overall functioning and depression and had fewer psychiatric diagnoses at the end of treatment. The WL group showed the same pattern of response to CBT as the group who had received CBT immediately. All treatment gains were maintained at follow-up assessment. Limitations The sample size is small and consists mainly of women with a high level of educational attainment and the follow-up period was relatively short. Conclusions These preliminary findings suggest that a focused, brief CBT intervention can be effective in treating LSE and associated symptoms and diagnoses in a clinically representative group of individuals with a range of different and co-morbid disorders.
Resumo:
Objective To undertake a process evaluation of pharmacists' recommendations arising in the context of a complex IT-enabled pharmacist-delivered randomised controlled trial (PINCER trial) to reduce the risk of hazardous medicines management in general practices. Methods PINCER pharmacists manually recorded patients’ demographics, details of interventions recommended, actions undertaken by practice staff and time taken to manage individual cases of hazardous medicines management. Data were coded and double entered into SPSS v15, and then summarised using percentages for categorical data (with 95% CI) and, as appropriate, means (SD) or medians (IQR) for continuous data. Key findings Pharmacists spent a median of 20 minutes (IQR 10, 30) reviewing medical records, recommending interventions and completing actions in each case of hazardous medicines management. Pharmacists judged 72% (95%CI 70, 74) (1463/2026) of cases of hazardous medicines management to be clinically relevant. Pharmacists recommended 2105 interventions in 74% (95%CI 73, 76) (1516/2038) of cases and 1685 actions were taken in 61% (95%CI 59, 63) (1246/2038) of cases; 66% (95%CI 64, 68) (1383/2105) of interventions recommended by pharmacists were completed and 5% (95%CI 4, 6) (104/2105) of recommendations were accepted by general practitioners (GPs), but not completed at the end of the pharmacists’ placement; the remaining recommendations were rejected or considered not relevant by GPs. Conclusions The outcome measures were used to target pharmacist activity in general practice towards patients at risk from hazardous medicines management. Recommendations from trained PINCER pharmacists were found to be broadly acceptable to GPs and led to ameliorative action in the majority of cases. It seems likely that the approach used by the PINCER pharmacists could be employed by other practice pharmacists following appropriate training.
Resumo:
Background Promising evidence has emerged of clinical gains using guided self-help cognitive-behavioural therapy (CBT) for child anxiety and by involving parents in treatment; however, the efficacy of guided parent-delivered CBT has not been systematically evaluated in UK primary and secondary settings. Aims To evaluate the efficacy of low-intensity guided parent-delivered CBT treatments for children with anxiety disorders. Method A total of 194 children presenting with a current anxiety disorder, whose primary carer did not meet criteria for a current anxiety disorder, were randomly allocated to full guided parent-delivered CBT (four face-to-face and four telephone sessions) or brief guided parent-delivered CBT (two face-to-face and two telephone sessions), or a wait-list control group (trial registration: ISRCTN92977593). Presence and severity of child primary anxiety disorder (Anxiety Disorders Interview Schedule for DSM-IV, child/parent versions), improvement in child presentation of anxiety (Clinical Global Impression-Improvement scale), and change in child anxiety symptoms (Spence Children’s Anxiety Scale, child/parent version and Child Anxiety Impact scale, parent version) were assessed at post-treatment and for those in the two active treatment groups, 6 months post-treatment. Results Full guided parent-delivered CBT produced superior diagnostic outcomes compared with wait-list at post-treatment, whereas brief guided parent-delivered CBT did not: at post-treatment, 25 (50%) of those in the full guided CBT group had recovered from their primary diagnosis, compared with 16 (25%) of those on the wait-list (relative risk (RR) 1.85, 95% CI 1.14-2.99); and in the brief guided CBT group, 18 participants (39%) had recovered from their primary diagnosis post-treatment (RR = 1.56, 95% CI 0.89-2.74). Level of therapist training and experience was unrelated to child outcome. Conclusions Full guided parent-delivered CBT is an effective and inexpensive first-line