Incomplete block designs with blocks of two plots

Various workers have shown that considerable economies in experimentation can be achieved by the use of identical twins, halves of leaves and halves of plants. The basic statistical principle enabling these economies is that of incomplete block designs. These make possible the comparison of treatments within pairs of identical twins, pairs of half-leaves or whatever grouping is used, so that experimental error arises only because of differences between individuals within the pairs. Extensive use of these natural groupings is possible only when the possible incomplete block designs have been enumerated. The purpose of this bulletin is to present what is essentially a complete array of incomplete block designs with blocks of two plots. The balanced incomplete block design requires (n-1) replications, where n is the number of treatments. Any design using a lesser number of replications must necessarily be unbalanced. Designs are presented which require (n-2), (n-3), ... , three replications, whenever such is possible, for any number of treatments between 6 and 12. These designs have been extracted from a pool of designs formed by (a) the class of partially balanced incomplete block designs with two classes of associates and (b) the class of circulant designs. The design chosen to cover each situation is the design which has the highest efficiency factor among all the designs in the pool applicable to the given situation. The tabulation of material necessary for the analysis of the respective designs is made to facilitate computations. The computations are exemplified by the inclusion of a worked example covering both the intrablock and interblock analysis

Significance of soil organic phosphorus to plant growth

The first indication that soils contain organic phosphorus was obtained in 1844 by Mulder (20), in experiments wherein he could not obtain phosphorus-free preparations of certain soil organic matter fractions. Since the time of Mulder, a number of investigations have dealt specifically with the problem of soil organic phosphorus, and it is now generally recognized that a portion of the soil phosphorus occurs in organic forms. The distribution of organic phosphorus in different soil types and groups has been investigated in only a preliminary way, but it has become apparent that the quantities of organic phosphorus are correlated with the quantities of soil organic matter. In Iowa and other North Central states, there are extensive areas of soils that contain relatively large quantities of both substances

Predicting sugar-sweetened behaviours with theory of planned behaviour constructs: Outcome and process results from the SIPsmartER behavioural intervention

Objective Guided by the theory of planned behaviour (TPB) and health literacy concepts, SIPsmartER is a six-month multicomponent intervention effective at improving SSB behaviours. Using SIPsmartER data, this study explores prediction of SSB behavioural intention (BI) and behaviour from TPB constructs using: (1) cross-sectional and prospective models and (2) 11 single-item assessments from interactive voice response (IVR) technology. Design Quasi-experimental design, including pre- and post-outcome data and repeated-measures process data of 155 intervention participants. Main Outcome Measures Validated multi-item TPB measures, single-item TPB measures, and self-reported SSB behaviours. Hypothesised relationships were investigated using correlation and multiple regression models. Results TPB constructs explained 32% of the variance cross sectionally and 20% prospectively in BI; and explained 13–20% of variance cross sectionally and 6% prospectively. Single-item scale models were significant, yet explained less variance. All IVR models predicting BI (average 21%, range 6–38%) and behaviour (average 30%, range 6–55%) were significant. Conclusion Findings are interpreted in the context of other cross-sectional, prospective and experimental TPB health and dietary studies. Findings advance experimental application of the TPB, including understanding constructs at outcome and process time points and applying theory in all intervention development, implementation and evaluation phases

Supporting maintenance of sugar-sweetened beverage reduction using automated versus live telephone support: Findings from a randomized control trial

This work is licensed under a Creative Commons Attribution 4.0 International License.Background Although reducing sugar-sweetened beverage (SSB) intake is an important behavioral strategy to improve health, no known SSB-focused behavioral trial has examined maintenance of SSB behaviors after an initial reduction. Guided by the RE-AIM framework, this study examines 6–18 month and 0–18 month individual-level maintenance outcomes from an SSB reduction trial conducted in a medically-underserved, rural Appalachia region of Virginia. Reach and implementation indicators are also reported. Methods Following completion of a 6-month, multi-component, behavioral RCT to reduce SSB intake (SIPsmartER condition vs. comparison condition), participants were further randomized to one of three 12-month maintenance conditions. Each condition included monthly telephone calls, but varied in mode and content: 1) interactive voice response (IVR) behavior support, 2) human-delivered behavior support, or 3) IVR control condition. Assessments included the Beverage Intake Questionnaire (BEVQ-15), weight, BMI, and quality of life. Call completion rates and costs were tracked. Analysis included descriptive statistics and multilevel mixed-effects linear regression models using intent-to-treat procedures. Results Of 301 subjects enrolled in the 6-month RCT, 242 (80%) were randomized into the maintenance phase and 235 (78%) included in the analyses. SIPsmartER participants maintained significant 0–18 month decreases in SSB. For SSB, weight, BMI and quality of life, there were no significant 6–18 month changes among SIPsmartER participants, indicating post-program maintenance. The IVR-behavior participants reported greater reductions in SSB kcals/day during the 6–18 month maintenance phase, compared to the IVR control participants (− 98 SSB kcals/day, 95% CI = − 196, − 0.55, p < 0.05); yet the human-delivered behavior condition was not significantly different from either the IVR-behavior condition (27 SSB kcals/day, 95% CI = − 69, 125) or IVR control condition (− 70 SSB kcals/day, 95% CI = − 209, 64). Call completion rates were similar across maintenance conditions (4.2–4.6 out of 11 calls); however, loss to follow-up was greatest in the IVR control condition. Approximated costs of IVR and human-delivered calls were remarkably similar (i.e., $3.15/participant/month or$38/participant total for the 12-month maintenance phase), yet implications for scalability and sustainability differ. Conclusion Overall, SIPsmartER participants maintained improvements in SSB behaviors. Using IVR to support SSB behaviors is effective and may offer advantages as a scalable maintenance strategy for real-world systems in rural regions to address excessive SSB consumption.National Institutes of Health, National Cancer Institute (R01CA154364

A hybrid actuator disc - full rotor CFD methodology for modelling the effects of wind turbine wake interactions on performance

The performance of individual wind turbines is crucial for maximum energy yield, however, their performance is often reduced when turbines are placed together in an array. The wake produced by the rotors interacts with downstream turbines, resulting in a reduction in power output. In this paper, we demonstrate a new and faster modelling technique which combines actuator disc theory, modelled using wind tunnel validated Computational Fluid Dynamics (CFD), and integrated into full rotor CFD simulations. This novel hybrid of techniques results in the ability to analyse performance when simulating various array layouts more rapidly and accurately than using either method on its own. It is shown that there is a significant power reduction from a downstream turbine that is subjected to the wake of an upstream turbine, and that this is due to both a reduction in power in the wind and also due to changes in the aerodynamics. Analysis of static pressure along the blade showed that as a result of wake interactions, a large reduction in the suction peak along the leading edge reduced the lift generated by the rotor and so reduced the torque production and the ability for the blade to extract energy from the wind

Integrating the promotion of physical activity within a smoking cessation programme: Findings from collaborative action research in UK Stop Smoking Services

Background: Within the framework of collaborative action research, the aim was to explore the feasibility of developing and embedding physical activity promotion as a smoking cessation aid within UK 6/7-week National Health Service (NHS) Stop Smoking Services. Methods: In Phase 1 three initial cycles of collaborative action research (observation, reflection, planning, implementation and re-evaluation), in an urban Stop Smoking Service, led to the development of an integrated intervention in which physical activity was promoted as a cessation aid, with the support of a theoretically based self-help guide, and self monitoring using pedometers. In Phase 2 advisors underwent training and offered the intervention, and changes in physical activity promoting behaviour and beliefs were monitored. Also, changes in clients’ stage of readiness to use physical activity as a cessation aid, physical activity beliefs and behaviour and physical activity levels were assessed, among those who attended the clinic at 4-week post-quit. Qualitative data were collected, in the form of clinic observation, informal interviews with advisors and field notes. Results: The integrated intervention emerged through cycles of collaboration as something quite different to previous practice. Based on field notes, there were many positive elements associated with the integrated intervention in Phase 2. Self-reported advisors’ physical activity promoting behaviour increased as a result of training and adapting to the intervention. There was a significant advancement in clients’ stage of readiness to use physical activity as a smoking cessation aid. Conclusions: Collaboration with advisors was key in ensuring that a feasible intervention was developed as an aid to smoking cessation. There is scope to further develop tailored support to increasing physical activity and smoking cessation, mediated through changes in perceptions about the benefits of, and confidence to do physical activity

A theory on reports of constructive (real) and illusory posttraumatic growth

It has been suggested that self-reported posttraumatic growth could sometimes be considered as a way for people to protect themselves from the distress of trauma. In this case, reports of posttraumatic growth could be illusory. We suggest a theory on self-reported constructive (real) posttraumatic growth and illusory posttraumatic growth by using Rogers’s (1959) theory and the work by Vaillant (1995). Through this theoretical framework we attempt to explain when reports of posttraumatic growth are likely to be constructive and real and when such reports are likely to represent aspects of illusions. We will also consider the implications for research practice

Retrospective Denial as A Coping Method

Worldwide, gastric cancer is one of the most common and fatal cancers. The majority of patients present with an advanced stage of disease. Even with use of palliative chemotherapy most patients die within 1 year after diagnosis. Medical psychological attention after a diagnosis of incurable cancer is focused on end of life support. This paper presents the care of a patient treated with palliative intent with chemotherapy for an irresectable histologically confirmed gastric cancer. When, unexpectedly prolonged symptom free survival followed, the reaction of the patient came as a surprise to the attending medical team. In this case history we urge those who care for incurable cancer patients, that the rare patient who survives against all odds may require special psychological care