On the advective model of the thermocline circulation

A theoretical study is made of the motion in the thermocline region of a large ocean. It is assumed that motion takes place under geostrophic and hydrostatic balance and that heat is transferred by convection only. Proper account is taken of the earth\u27s spherical geometry. A class of solutions of the mathematical problem is derived and one of these, an inverse power solution, is discussed in detail. The solution does not satisfy all the details of the known physical situation but shows reasonable qualitative agreement with it...

Condensation and partial pressure change as a major cause of airflow: experimental evidence

The dominant model of atmospheric circulation is based on the notion that hot air rises, creating horizontal winds. A second major driver has been proposed in the biotic pump theory (BPT), by which intense condensation is the prime cause of surface winds from ocean to land. Critics of the BPT argue that air movement resulting from condensation is isotropic. This paper explores the physics of water condensation under mild atmospheric conditions, within a purpose-designed square-section 4.8m-tall closed-system structure. The data show a highly significant correlation (R2 >0.96, p value <0.001) between observed airflows and partial pressure changes from condensation. The assumption that condensation of water vapour is always isotropic is therefore incorrect

Research and theory for nursing and midwifery: Rethinking the nature of evidence

Background and Rationale: The rise in the principles of evidence-based medicine in the 1990s heralded a re-emerging orthodoxy in research methodologies. The view of the randomised controlled trial (RCT) as a “gold standard” for evaluation of medical interventions has extended recently to evaluation of organisational forms and reforms and of change in complex systems—within health care and in other human services. Relatively little attention has been given to the epistemological assumptions underlying such a hierarchy of research evidence. Aims and Methods: Case studies from research in maternity care are used in this article to describe problems and limitations encountered in using RCTs to evaluate some recent policy-driven and consumer-oriented developments. These are discussed in relation to theory of knowledge and the epistemological assumptions, or paradigms, underpinning health services research. The aim in this discussion is not to advocate, or to reject, particular approaches to research but to advocate a more open and critical engagement with questions about the nature of evidence. Findings and Discussion: Experimental approaches are of considerable value in investigating deterministic and probabilistic cause and effect relationships, and in testing often well-established but unevaluated technologies. However, little attention has been paid to contextual and cultural factors in the effects of interventions, in the culturally constructed nature of research questions themselves, or of the data on which much research is based. More complex, and less linear, approaches to methodology are needed to address these issues. A simple hierarchical approach does not represent the complexity of evidence well and should move toward a more cyclical view of knowledge development

The process of establishing implementing and maintaining a social support infant feeding programme

Objective To describe the process of establishing and implementing a social support infant feeding intervention. Design This paper outlines the initial stages of a randomised controlled trial which assessed the effectiveness of a social support intervention on a range of infant feeding outcomes. Details are presented of the processes involved in recruiting, training and supporting a group of volunteers who provided support to the study sample. Setting Camden and Islington, London, UK. Results Initial networking with local agencies and organisations provided invaluable information and contacts. Employing a dedicated volunteer co-ordinator is vitally important in the recruitment, training and support of volunteers. Providing child care and travel expenses is an essential incentive for volunteers with young children. Advertisements placed in local newspapers were the most successful means of recruiting volunteers. Appropriate training is needed to equip volunteers with the necessary knowledge and skills to provide effective support. Particular emphasis in the training focused upon developing the necessary interpersonal skills and self-confidence. The evaluation of the training programme demonstrated that it improved volunteers’ knowledge and reported confidence. The provision of ongoing support is also essential to maintain volunteers’ interest and enthusiasm. The retention of volunteers is, however, a key challenge. Conclusions The processes outlined in this paper have demonstrated the feasibility of successfully establishing, implementing and maintaining a community-based social support infant feeding programme. The experiences described provide useful insights into the practical issues that need to be addressed in setting up a social support intervention

Further experimental evidence that condensation is a major cause of airflow

This paper further explores the physics of water condensation, using an experimental structure designed for that purpose. The data show a highly significant correlation (R2 >0.94, p value <0.001) between observed airflows and partial pressure changes from condensation, when the results of different experiments are pooled. Changes in air density on cooling provide insufficient energy to account for the airflow. The finding is that the kinetic energy of the chilled air falls short by an order of magnitude, even to move a relatively small proportion of the 20 kg of air contained within the structure. Meanwhile the physics of condensation indicate a surplus of kinetic energy is made available from the air surrounding the locus of condensation. At low rates of condensation a considerable proportion of the available kinetic energy in the enclosed air is absorbed in friction and turbulence. That proportion reduces with higher rates of condensation

Hydrological processes and water resources management in a dryland environment II: Surface redistribution of rainfall within fields

International audienceSoil water movement was studied within fields on two different soil types, a red clay soil and a duplex soil of sand over clay, at the Romwe Catchment in southern Zimbabwe. Each study site comprised two fields and formed a surface water sub-catchment (1.0-2.4 ha) from which runoff was gauged. Soil moisture was measured in-situ at up to 20 locations within each sub-catchment over an entire cropping season and the following dry season. Maize was cultivated at both sites according to the farmers' normal cropping practice and crop yields were recorded. Surface redistribution of rainfall through localised runon and runoff was shown to be an important process in both sub-catchments with rainfall concentration factors between 0.2 and 2.7 for major rainfall events. This process was a key factor controlling deep drainage to groundwater. Results indicate that surface water redistribution is of particular importance for groundwater recharge in years with low or evenly distributed rainfall, when it would not otherwise have occurred. The soil water conditions created by surface redistribution of rainfall are also actively exploited by farmers who vary cropping practices within fields to maximise crop yields and reduce the risks of crop failure

(E)-4-[(4-Bromo­benzyl­idene)amino]phenol

In the title compound, C13H10BrNO, the dihedral angle between the benzene rings is 35.20 (8)°. In the crystal, mol­ecules are linked by O—H⋯N hydrogen bonds, forming a zigzag chain along the a axis. A weak C—H⋯π inter­action is observed between the chains

1,2-Bis[(1,3-benzodioxol-5-yl)methyl­idene]hydrazine

The complete mol­ecule of the title compound, C16H12N2O4, is generated by the application of a centre of inversion. The (1,3-benzodioxol-5-yl)methyl­idene fused-ring system is approximately planar (r.m.s. deviation = 0.020 Å) and is essentially coplanar with the central hydrazine group [dihedral angle = 5.08 (9)°]. Weak π–π inter­molecular inter­actions are observed [centroid–centroid distance = 3.8553 (8) Å], providing some packing stability