Energy Spectrum Evolution of a Diffuse Field in Elastic Body Caused by Weak Nonlinearity

We study the evolution of diffuse elastodynamic spectral energy density under the influence of weak nonlinearity. It is shown that the rate of change of this quantity is given by a convolution of the linear energy at two frequencies. Quantitative estimates are given for sample aluminum and fused silica blocks of experimental interest.Comment: 9 pages, 3 figures; revised for better presentatio

The design of linear multivariable control systems using modern control theory /with applications to coupled core reactor control/

Linear multivariable control system design using modern control theory, and application to coupled core reactor contro

A Proportion Method for Sampling Spittlebug Populations

Author Institution: Department of Entomology, Ohio Agricultural Experiment Station, Wooster, and Department of Mathematics, The Ohio State University, Columbus 1

Development and initial operating characteristics of the 20 megawatt linear plasma accelerator facility

A 20-megawatt linear plasma accelerator facility, a steady flow, Faraday-type plasma accelerator facility for high velocity aerodynamic testing, was constructed, developed, and brought to an operational status. The accelerator has a 63.5-mm-square and 0.5-meter-long channel and utilizes nitrogen-seeded with 2 % mole fraction of cesium vapor. Modification of the original accelerator design characteristics and the improvements necessary to make the arc heater a suitable plasma source are described. The measured accelerator electrode current distribution and the electrode-wall potential distributions are given. The computed and the measured values are in good agreement. Measured pitot pressure indicates that an accelerator exit velocity of 9.2 km/sec, is obtained with 30 of the 36 electrode pairs powered and corresponds to a velocity increase to about 2 1/4 times the computed entrance velocity. The computed stagnation enthalpy at the accelerator exit is 92 MJ/kg, and the mass density corresponds to an altitude of about 58 km. The 92 MJ/kg stagnation enthalpy corresponds to a kinetic energy content at low temperature equivalent to a velocity of 13.6 km/sec

Macroeconomics and the Nexus between Energy and Agricultural Commodities Prices

The variation of energy prices has been a traditional source of shocks to the real economy. In many cases, this variation has manifested in jumps in energy prices that were characterized by some persistence. From another perspective, energy price volatility has historically been noted and its effects on real economy debated. Historically, the importance of the shocks to the real economy has led them to be labeled as energy crises, as they were argued to have resulted in substantial changes in real prices that induced changes in behavior on the demand and supply sides of the many markets. However, empirical studies of transmission of energy prices into the real economy have produced no consensus and have been challenged by a number of significant specification issues that have resulted in substantial variation in inference drawn from results. Among these issues is the question of completeness of model specification. This paper examines the question of whether such models need to incorporate macroeconomic indicators. Clearly, macroeconomic factors such as interest rates and exchange rates play a role in the determination of energy and commodity prices, however, considerable specification uncertainty characterizes the question of which macro metrics to incorporate. This paper examines this issue from the perspective of weak exogeneity and finds evidence that the parameter estimates associated with time series models that exclude consideration of macro indicators are not compromised by their exclusion. We examine this issue using Italian, U.S. grain, and Brent crude oil prices

Research on a one-inch-square linear d-c plasma accelerator

One-inch-square linear d-c plasma accelerator using cesium seeded nitroge

Experiences of parenting and clinical intervention for mothers affected by personality disorder: a pilot qualitative study combining parent and clinician perspectives

Background: Evidence-based parenting programmes are recommended for the treatment of child mental health difficulties. Families with complex psychosocial needs show poorer retention and outcomes when participating in standard parenting programmes. The Helping Families Programme (HFP) is a 16-week community-based parenting intervention designed to meet the needs of these families, including families with parental personality disorder. This study aimed to explore the help seeking and participatory experiences of parents with a diagnosis of personality disorder. It further aimed to examine the acceptability of referral and intervention processes for the HFP from the perspectives of (i) clinicians referring into the programme; and (ii) referred parents. Method: Semi-structured interviews were conducted with parents recruited to receive HFP (n = 5) as part of a research case series and the referring NHS child and adolescent mental health service (CAMHS) clinicians (n = 5). Transcripts were analysed using Interpretive Phenomenological Analysis. Results: Four themes were identified for parents: (i) the experience of parenthood, (ii) being a parent affected by personality disorder, (iii) experience of the intervention, and (iv) qualities of helping. Three themes emerged for clinicians: (i) challenges of addressing parental need, (ii) experience of engaging parents with personality disorders and (iii) limited involvement during HFP. Comparison of parent and clinician themes led to the identification of two key interlinked themes: (i) concerns prior to receiving the intervention, and (ii) the challenges of working together without a mutual understanding. Conclusions: This pilot study identifies potentially significant challenges of working with parents affected by personality disorder and engaging them in HFP and other similar interventions. Results have important wider clinical implications by highlighting potential barriers to engagement and participation and providing insights on how these barriers might be overcome. Findings have been used to inform the referral and intervention processes of a pilot RCT and further intervention development

Role of oxygen in the electron-doped superconducting cuprates

We report on resistivity and Hall measurements in thin films of the electron-doped superconducting cuprate Pr$_{2-x}$Ce$_{x}$CuO$_{4\pm\delta}$. Comparisons between x = 0.17 samples subjected to either ion-irradiation or oxygenation demonstrate that changing the oxygen content has two separable effects: 1) a doping effect similar to that of cerium, and 2) a disorder effect. These results are consistent with prior speculations that apical oxygen removal is necessary to achieve superconductivity in this compound.Comment: 5 pages, 5 figure

Effect of exogenous gibberellin on endogenous hormone content and development of 'Black Corinth' grapes

The relationship between growth and development of potassium gibberellate (KGA3 )-treated 'Black Corinth' berries and changes in the level of hormones was studied from anthesis to maturity. Growth rate curves for fresh weight and volume had peaks corresponding to stages I and III. The curve for dry weight showed only one large pea k that occurred in stage III. Associated with the first period of rapid growth (stage I) was a rapid increase in concentration of hormone. Application of KGA3 increased auxin activity within 3 hours after treatment, and berries from KGA3-treated vines maintained a higher level of auxin activity during stage I and stage II than did berries from untreated vines. Hormone content decreased during the period of retarded growth (stage II), and continued at a low level until harvest

Influences on recruitment to randomised controlled trials in mental health settings in England: a national cross-sectional survey of researchers working for the Mental Health Research Network

Background: Recruitment to trials is complex and often protracted; selection bias may compromise generalisability. In the mental health field (as elsewhere), diverse factors have been described as hindering researcher access to potential participants and various strategies have been proposed to overcome barriers. However, the extent to which various influences identified in the literature are operational across mental health settings in England has not been systematically examined. Methods: A cross-sectional, online survey of clinical studies officers employed by the Mental Health Research Network in England to recruit to trials from National Health Service mental health services. The bespoke questionnaire invited participants to report exposure to specified influences on recruitment, the perceived impact of these on access to potential participants, and to describe additional positive or negative influences on recruitment. Analysis employed descriptive statistics, the framework approach and triangulation of data. Results: Questionnaires were returned by 98 (58%) of 170 clinical studies officers who reported diverse experience. Data demonstrated a disjunction between policy and practice. While the particulars of trial design and various marketing and dommunication strategies could influence recruitment, consensus was that the culture of NHS mental health services is not donducive to research. Since financial rewards for recruitment paid to Trusts and feedback about studies seldom reaching frontline services, clinicians were described as distanced from research. Facing continual service change and demanding clinical workloads, clinicians generally did not prioritise recruitment activities. Incentives to trial participants had variable impact on access but recruitment could be enhanced by engagement of senior investigators and integrating referral with routine practice. Comprehensive, robust feasibility studies and reciprocity between researchers and clinicians were considered crucial to successful recruitment. Conclusions: In the mental health context, researcher access to potential trial participants is multiply influenced. Gatekeeping clinicians are faced with competing priorities and resources constrain research activity. It seems that environmental adjustment predicated on equitable resource allocation is needed if clinicians in NHS mental health services are to fully support the conduct of randomised controlled trials. Whilst cultural transformation, requiring changes in assumptions and values, is complex, our findings suggest that attention to practical matters can support this and highlight issues requiring careful consideration