A new view of the spin echo diffusive diffraction on porous structures

Analysis with the characteristic functional of stochastic motion is used for the gradient spin echo measurement of restricted motion to clarify details of the diffraction-like effect in a porous structure. It gives the diffusive diffraction as an interference of spin phase shifts due to the back-flow of spins bouncing at the boundaries, when mean displacement of scattered spins is equal to the spin phase grating prepared by applied magnetic field gradients. The diffraction patterns convey information about morphology of the surrounding media at times long enough that opposite boundaries are restricting displacements. The method explains the dependence of diffraction on the time and width of gradient pulses, as observed at the experiments and the simulations. It also enlightens the analysis of transport properties by the spin echo, particularly in systems, where the motion is restricted by structure or configuration

The effect of exercise on depressive symptoms in adolescents: a systematic review and meta-analysis

Objective: The purpose of this review was to examine the treatment effect of physical exercise on depressive symptoms for adolescents aged 13 to 17 years. Method: A systematic search of 7 electronic databases identified relevant randomized controlled trials. Following removal of duplicates, 543 texts were screened for eligibility. Screening, data extraction, and trial methodological quality assessment (using the Delphi list) were undertaken by 2 independent researchers. Standardized mean differences were used for pooling postintervention depressive symptom scores. Results: Eleven trials met the inclusion criteria, 8 of which provided the necessary data for calculation of standardized effect size. Exercise showed a statistically significant moderate overall effect on depressive symptom reduction (standardized mean difference [SMD] = −0.48, 95% CI = −0.87, −0.10, p = .01, I2 = 67%). Among trials with higher methodological scoring, a nonsignificant moderate effect was recorded (SMD = −0.41, 95% CI = −0.86, 0.05, p = .08). In trials with exclusively clinical samples, exercise showed a statistically significant moderate effect on depressive symptoms with lower levels of heterogeneity (SMD = −0.43, 95% CI = −0.84, −0.02, p = .04, I2 = 44%). Conclusion: Physical exercise appears to improve depressive symptoms in adolescents, especially in clinical samples in which the moderate antidepressant effect, higher methodological quality, and lowered statistical heterogeneity suggest that exercise may be a useful treatment strategy for depression. Larger trials with clinical samples that adequately minimize the risk of bias are required for firmer conclusions on the effectiveness of exercise as an antidepressant treatment

An exploration of predictors of children's nurses' attitudes, knowledge, confidence and clinical behavioural intentions towards children and young people who self-harm

Aims and objectives: To explore the potential predictors of children's nurses? attitudes, knowledge and confidence towards caring for children and young people admitted to hospital with self-harm. Background Admissions to paediatric inpatient settings for individuals who have self-harmed are growing. Limited previous research suggests that nurses have mixed attitudes towards people who have self-harmed and potentially lack the confidence to provide effective care. There is a specific paucity of research in this area for children's nurses. Design: A cross-sectional descriptive survey was used to gather data for exploration of variables associated with attitudes, confidence, knowledge and clinical behavioural intentions of 98 registered children's nurses in a single tertiary children's hospital, colocated in a large acute NHS Trust in the UK. Methods: Data were collected over a 4 weeks in 2015, using an online survey tool. The predictive effect of several demographic variables was tested on the outcomes of attitudes, knowledge, confidence and behavioural intentions, which were collected using relevant, previously used outcome measures. Results: Increased experience was found to be associated with improved attitudes relating to negativity. Previous training in caring for children who had self-harmed was found to be associated with improved attitudes around perceived effectiveness of their care. Higher academic qualifications and having undertaken previous training on self-harm were each found to be associated with increased knowledge of self-harm, and increased age was associated with reduced knowledge of self-harm. Conclusions: This study provides an initial exploration of variables associated with attitudes, knowledge, confidence and behaviour intentions of registered children's nurses in relation to caring for CYP who have self-harmed. Relevance to clinical practice: Targeted training on caring for CYP who have self-harmed should be considered as a component of continuing education for registered children's nurses in the UK to improve the experience and outcomes for this patient group

The effectiveness of a preferred intensity exercise programme on the mental health outcomes of young people with depression: A sequential mixed methods evaluation

Background: People with mental illness are more likely to suffer physical health problems than comparable populations who do not have mental illness. There is evidence to suggest that exercise, as well has having obvious physical benefits, also has positive effects on mental health. There is a distinct paucity of research testing its effects on young people seeking help for mental health issues. Additionally, it is generally found that compliance with prescribed exercise programmes is low. As such, encouraging young people to exercise at levels recommended by national guidelines may be unrealistic considering their struggle with mental health difficulties. It is proposed that an exercise intervention tailored to young people's preferred intensity may improve mental health outcomes, overall quality of life, and reduce exercise attrition rates. Methods/Design. A sequential mixed methods design will be utilised to assess the effectiveness of an individually tailored exercise programme on the mental health outcomes of young people with depression. The mixed methods design incorporates a Randomised Controlled Trial (RCT), focus groups and interviews and an economic evaluation. Participants: 158 young people (14-17 years) recruited from primary care and voluntary services randomly allocated to either the intervention group or control group. Intervention group: Participants will undertake a 12 week exercise programme of 12 × 60 minutes of preferred intensity aerobic exercise receiving motivational coaching and support throughout. Participants will also be invited to attend focus groups and 1-1 interviews following completion of the exercise programme to illicit potential barriers facilitators to participation. Control group: Participants will receive treatment as usual. Primary Outcome measure: Depression using the Children's Depression Inventory 2 (CDI-2). Secondary Outcome measures: Quality of Life (EQ-5D), physical fitness (Borg RPE scale, heart rate), incidents of self-harm, treatment received and compliance with treatment, and the cost effectiveness of the intervention. Outcome measures will be taken at baseline, post intervention and 6 month follow up. Discussion. The results of this study will inform policy makers of the effectiveness of preferred intensity exercise on the mental health outcomes of young people with depression, the acceptability of such an intervention to this population and its cost effectiveness. © 2012 Carter et al; licensee BioMed Central Ltd

Pragmatic randomised controlled trial of preferred intensity exercise in women living with depression

Background: Exercise may be effective in treating depression, but trials testing its effect in depressed women are rare. Aim. To compare the effect of exercise of preferred intensity with exercise of prescribed intensity in thirty-eight women living with depression. Methods. A Pragmatic RCT of 12 sessions of exercise at preferred intensity compared with 12 sessions at prescribed intensity. Beck Depression Inventory (BDI), Rosenberg Self Esteem Scale (RSES), General Health Questionnaire 12 (GHQ-12), heart rate (HR), Rating of Perceived Exertion Scale (RPE), Quality of Life in Depression Scale (QLDS), Multi-Dimensional Scale of Perceived Social Support (MDSPSS), SF12 Health Survey and exercise participation rates were compared between groups. Results: Intervention participants had statistically better BDI (t = 2.638, df = 36, p = 0.006, 95% mean (SD) 26.5 (10.7), CI-20.4 to -2.7, d = 0.86), GHQ-12 (t = 3.284, df = 36, p = 0.001, mean (SD) 8.3 (3.7) 95% CI -6.5 to -1.5, d = 1.08), RSES (t = 2.045, df = 36, p = 0.024, mean (SD) 11.3 (5.8), 95% CI 0.3 -6.4, d = 0.25), QLDS (t = 1.902, df = 36, p = 0.0325, mean (SD) 15.5 (7.9), 95% CI -12.2 -0.4, d = 0.27) RPE scores (t = 1.755, df = 36, p = 0.0475, mean (SD) 9.2 (3.2), 95% CI -.5 - 5.2, d = 0.77) and attended more exercise sessions (t = 1.781, df = 36, p = 0.0415, number of sessions 8 (65%), 95% CI-0.3 -4.8, d = 0.58). SF-12, MSPSS and HR did not differ significantly between groups. Conclusions: Exercise of preferred intensity improves psychological, physiological and social outcomes, and exercise participation rates in women living with depression. © 2011 Callaghan et al; licensee BioMed Central Ltd

Inlet morpho-dynamics during a storm event inferred from tidal records: a case study of the Brunswick River, NSW, Australia

A 24.5h moving window is used to analyse storm effects on the tidal dynamics. Compared to earlier studies using window lengths varying between 2h (for tsunami analysis) to 14 days for tidal inlet analysis, the present method provides good resolution of variations of hydraulic efficiency during storms or floods. The importance of de-trending before carrying out the harmonics analysis has been studied and it was found to be highly important. De-trending involved removing the 24.5h mean before harmonic analysis. The main results are the morphodynamic timescale Tmorph and the varying response functions F1 and F2 of the diurnal and semi-diurnal tidal constituents through a storm event at the Brunswick River, Australia. Tmorph is inferred from time series of primary semi-diurnal gain G2(t) = |F2 | with an exp(-t/Tmorph) curve fit. The results show only insignificant morphological change. Thus, the changes in tidal response for this medium sized catchment are mainly due to hydraulic effects. These include the influence of river flow Qf via the non-linear friction term and increased estuary surface area during the flood. The traces of both F1(t) and F2(t) in the complex plane show an equilibrium before the storm, dynamic change during the storm and relaxation mimicked by exp(-t/Tmorph) after the storm

Morphology of coastal lagoon entrances: waves versus tides

Lagoon inlets and river entrances on sandy coasts are shaped by waves, tides and freshwater outflows interacting subject to geological constraints. In dimensionless terms the relative importance of fresh water discharge Q versus peak tidal discharge Q is quantified simply by Q/Q, where the tidal peak discharge may be taken either as the actual Q = ωaA corresponding to the actual bay tidal amplitude aB or the potential Q = ωaA, which is based on the ocean tide amplitude aO. ω is the tidal angular frequency and A is the bay surface area at mid tide. The quantification of the relative strength of waves versus tides is less obvious and has not previously been clearly resolved. The case is made here for it being quantified by (Equation presented), where tidal dominance resulting in the canonical funnel shaped estuary occurs for (Equation presented) and, at the other end of the spectrum, intermittently open/closed systems (ICOLLS) occur for (Equation presented) denotes the average offshore significant wave height and g is acceleration due to gravity. More comprehensive data may lead to the inclusion of the wave period as well as the wave height in future formulations

Chain Deformation for a Polymer Melt under Shear

We used a Couette cell placed within an NMR microscopy apparatus to examine molecular alignment in polydimethylsiloxane melts under shear. 1H dipolar interactions are used to examine main chain ordering while 2H NMR quadrupole splittings are measured in a deuterated oligomer probe, in each case selectively observing different alignment orientations with respect to the flow field. While the main chain results are consistent with the alignment tensor as measured by birefringence, the oligomer senses a uniaxial environment whose director is normal to the velocity-vorticity plane. In the light of these results we propose supramolecular ordering involving polymer stratification

Dynamic decoherence control of a solid-state nuclear quadrupole qubit

We report on the application of a dynamic decoherence control pulse sequence on a nuclear quadrupole transition in $Pr^{3+}:Y_2SiO_5$ . Process tomography is used to analyse the effect of the pulse sequence. The pulse sequence was found to increase the decoherence time of the transition to over 30 seconds. Although the decoherence time was significantly increased, the population terms were found to rapidly decay on the application of the pulse sequence. The increase of this decay rate is attributed to inhomogeneity in the ensemble. Methods to circumvent this limit are discussed.Comment: 4 pages, 6 figure