55 resultados para CURRENT SELF-OSCILLATION


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Flexible energy devices with high performance and long-term stability are highly promising for applications in portable electronics, but remain challenging to develop. As an electrode material for pseudo-supercapacitors, conducting polymers typically show higher energy storage ability over carbon materials and larger conductivity than transition-metal oxides. However, conducting polymer-based supercapacitors often have poor cycling stability, attributable to the structural rupture caused by the large volume contrast between doping and de-doping states, which has been the main obstacle to their practical applications. Herein, we report a simple method to prepare a flexible, binder-free, self-supported polypyrrole (PPy) supercapacitor electrode with high cycling stability through using novel, hollow PPy nanofibers with porous capsular walls as a film-forming material. The unique fiber structure and capsular walls provide the PPy film with enough free-space to adapt to volume variation during doping/de-doping, leading to super-high cycling stability (capacitance retention > 90% after 11000 charge-discharge cycles at a high current density of 10 A g-1) and high rate capability (capacitance retention ∼ 82.1% at a current density in the range of 0.25-10 A g-1).

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Background Monitoring athlete well-being is essential to guide training and to detect any progression towards negative health outcomes and associated poor performance. Objective (performance, physiological, biochemical) and subjective measures are all options for athlete monitoring. Objective We systematically reviewed objective and subjective measures of athlete well-being. Objective measures, including those taken at rest (eg, blood markers, heart rate) and during exercise (eg, oxygen consumption, heart rate response), were compared against subjective measures (eg, mood, perceived stress). All measures were also evaluated for their response to acute and chronic training load. Methods The databases Academic search complete, MEDLINE, PsycINFO, SPORTDiscus and PubMed were searched in May 2014. Fifty-six original studies reported concurrent subjective and objective measures of athlete well-being. The quality and strength of findings of each study were evaluated to determine overall levels of evidence. Results Subjective and objective measures of athlete well-being generally did not correlate. Subjective measures reflected acute and chronic training loads with superior sensitivity and consistency than objective measures. Subjective well-being was typically impaired with an acute increase in training load, and also with chronic training, while an acute decrease in training load improved subjective well-being. Summary This review provides further support for practitioners to use subjective measures to monitor changes in athlete well-being in response to training. Subjective measures may stand alone, or be incorporated into a mixed methods approach to athlete monitoring, as is current practice in many sport settings.

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This work comprises of a series of video portraits and sound recordings that explore the connections between gesture, gaze and voice in video portraiture. Most of the subjects are artists represented in the current exhibition, but the disjunction between sound and image makes it difficult to categorically identify the authors of the sound bites on the work’s soundtrack. Designed to function as an introduction to the themes and issues generated by the Self/Persona relationship in the nascent field of Persona Studies, the work is also concerned with the presentation of the artistic self, and the ‘loss of self’ that may or may not occur as a consequence of artistic practice. Formally, the piece plays with the repetition and symmetry to underscore the vulnerability and mutability of the self within contemporary culture.

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BACKGROUND AND OBJECTIVES: Following observations in the literature that obsessions often contain or imply negative evaluative information about the self, Aardema et al. (2013) recently developed a measure of feared-self relevant to OCD. The current study aimed to provide further examination of the relevance of such feared self-beliefs to obsessive compulsive processes - in particular whether they partially underlie doubt in OCD-relevant situations. METHOD: Nonclinical participants (N = 463; 291 females; Mage = 25.17, SD = 7.47), were presented with three vignettes, related to washing, checking and non-OCD relevant themes, which assessed doubt through providing alternating sensory and possibility-based information. RESULTS: Higher levels of OCD symptoms and feared-self beliefs both significantly predicted both higher baseline levels of doubt and greater fluctuation in levels of doubt in both the contamination and checking scenarios, and to a much lesser extent in the control scenario. Feared-self beliefs did not predict fluctuation in doubt over-and-above OCD symptoms, consistent with a mediation model. LIMITATIONS: The main limitation was the use of a non-clinical sample, although this allowed sufficient participant numbers to test hypotheses. CONCLUSIONS: The findings provided further experimental support for reasoning processes in OCD, and suggested that feared self-beliefs may make individuals vulnerable to experiencing doubt. Additionally, these results suggested that individuals with high OCD symptoms and those with high feared self-beliefs are unable to recognise the improbable nature of possibility-based statements. Implications for treatment and theory are discussed.

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We report a new method for ultrasensitive detection of Cu(2+), which is based on changes in the tunnelling recognition current across self-assembled core-satellite gold nanoparticles (GNPs) networks functionalised with amino acids (l-cysteine). The addition of copper ions induces the formation of GNP/l-cysteine/Cu(2+)/l-cysteine/GNP molecular junctions and generates a significant decrease in the resistance through the networks. The networks are ultrasensitive to over ten orders range of copper ion concentrations.

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Cognitive-behavioural models have linked unacceptable or repugnant thoughts in obsessive-compulsive disorder (OCD) with vulnerable self-themes and fear-of-self concerns. To investigate this notion, Aardema and coworkers recently developed and validated the Fear of Self-Questionnaire (FSQ) in non-clinical samples, finding it had strong internal inconsistency, and good divergent and convergent validity, including strong relationships to obsessional symptoms and with other processes implicated in cognitive models of OCD (e.g., obsessive beliefs and inferential confusion). The current article describes two studies that aim to replicate and extend these findings in clinical OCD and non-clinical samples. Study 1 investigated the psychometric properties of an Italian translation of the FSQ in a non-clinical sample (n=405). Results of confirmatory factor analysis supported the unidimensionality of the scale; the FSQ also showed very good internal consistency and temporal stability. Study 2 investigated the role of fear of self in OCD symptoms, and unacceptable thoughts and repugnant obsessions in particular, using a clinical OCD sample (n=76). As expected, fear of self was a unique, major predictor of unacceptable thoughts independent of negative mood states and obsessive beliefs. Moreover, even when considered with obsessive beliefs, anxiety and depression, the feared self was the only unique predictor of obsessionality, providing support for the notion that self-themes could explain why some intrusions convert into obsessions, whereas others do not. Implications for current cognitive-behavioural models are discussed.

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Although psychiatric crises are very common in people with mental illness, little is known about consumer perceptions of mental health crisis care. Given the current emphasis on recovery-oriented approaches, shared decision-making, and partnering with consumers in planning and delivering care, this knowledge gap is significant. Since the late 1990s, access to Australian mental health services has been facilitated by 24/7 telephone-based mental health triage systems, which provide initial psychiatric assessment, referral, support, and advice. A significant proportion of consumers access telephone-based mental health triage services in a state of crisis, but to date, there has been no published studies that specifically report on consumer perceptions on the quality and effectiveness of the care provided by these services. This article reports on a study that investigated consumer perceptions of accessing telephone-based mental health triage services. Seventy-five mental health consumers participated in a telephone interview about their triage service use experience. An eight-item survey designed to measure the responsiveness of mental health services was used for data collection. The findings reported here focus on the qualitative data produced in the study. Consumer participants shared a range of perspectives on telephone-based mental health triage that provide invaluable insights into the needs, expectations, and service use experiences of consumers seeking assistance with a mental health problem. Consumer perceptions of crisis care have important implications for practice. Approaches and interventions identified as important to quality care can be used to inform educational and practice initiatives that promote person-centred, collaborative crisis care.

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Background/Aims Primary care is expected to develop strategies to manage obese patients as part of coronary heart disease and diabetes national service frameworks. Little is known about current management practices for obesity in this setting. The aim of this study is to examine current approaches to obesity management in UK primary care and to identify potential gaps in care.

Method A total of 141 general practitioners (GPs) and 66 practice nurses (PNs) from 40 primary care practices participated in structured interviews to examine clinician self-reported approaches to obesity management. Medical records were also reviewed for 100 randomly selected obese patients from each practice [body mass index (BMI) ≥30 kg m−2, n = 4000] to review rates of diet counselling, dietetic or obesity centre referrals, and use of anti-obesity medication. Computerized medical records for the total practice population (n = 206 341, 18–75 years) were searched to examine the proportion of patients with a weight/BMI ever recorded.

Results Eighty-three per cent of GPs and 97% of PNs reported that they would raise weight as an issue with obese patients (P < 0.01). Few GPs (15%) reported spending up to 10 min in a consultation discussing weight-related issues, compared with PNs (76%; P < 0.001). Over 18 months, practice-based diet counselling (20%), dietetic (4%) and obesity centre (1%) referrals, and any anti-obesity medication (2%) were recorded. BMI was recorded for 64.2% of patients and apparent prevalence of obesity was less than expected.

Conclusion Obesity is under-recognized in primary care even in these 40 practices with an interest in weight management. Weight management appears to be based on brief opportunistic intervention undertaken mainly by PNs. While clinicians report the use of external sources of support, few patients are referred, with practice-based counselling being the most common intervention.

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Reminiscence-based psychotherapies have been demonstrated to have robust effects on a range of therapeutic outcomes. However, little research has been conducted on the immediate effects of guided activities they are composed of, or how these might differ dependent on the type of reminiscence. The current study utilised a controlled experimental design, whereby 321 young adults (mean age = 25.5 years, SD = 3.0) were randomised to one of four conditions of online reminiscence activity: problem-solving (successful coping experiences), identity (self-defining events contributing to a meaningful and continuous personal identity), bitterness revival (negative or adverse events), or a control condition (any memory from their past). Participants recalled autobiographical memories congruent with the condition, and answered questions to facilitate reflection on the memories. The results indicated that problem-solving and identity reminiscence activities caused significant improvements in self-esteem, meaning in life, self-efficacy and affect, whereas no effects were found in the bitterness revival and control conditions. Problem-solving reminiscence also caused a small effect in increasing perceptions of a life narrative/s. Differences between the conditions did not appear to be explained by the positive-valence of memories. These results provide evidence for the specific effects of adaptive types of problem-solving and identity reminiscence in young adults.

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BACKGROUND: The ubiquitous use of mobile phones provides an ideal opportunity to deliver interventions to increase physical activity levels. Understanding potential mediators of such interventions is needed to increase their effectiveness. A recent randomized controlled trial of a mobile phone and Internet (mHealth) intervention was conducted in New Zealand to determine the effectiveness on exercise capacity and physical activity levels in addition to current cardiac rehabilitation (CR) services for people (n = 171) with ischemic heart disease. Significant intervention effect was observed for self-reported leisure-time physical activity and walking, but not peak oxygen uptake at 24 weeks. There was also significant improvement in self-efficacy.

OBJECTIVE: To evaluate the mediating effect of self-efficacy on physical activity levels in an mHealth delivered exercise CR program.

METHODS: Treatment evaluations were performed on the principle of intention to treat. Adjusted regression analyses were conducted to evaluate the main treatment effect on leisure-time physical activity and walking at 24 weeks, with and without change in self-efficacy as the mediator of interest.

RESULTS: Change in self-efficacy at 24 weeks significantly mediated the treatment effect on leisure-time physical activity by 13%, but only partially mediated the effect on walking by 4% at 24 weeks.

CONCLUSION: An mHealth intervention involving text messaging and Internet support had a positive treatment effect on leisure-time physical activity and walking at 24 weeks, and this effect was likely mediated through changes in self-efficacy. Future trials should examine other potential mediators related to this type of intervention.