Adaptive Co-management in the Context of Informal Settlements

Adaptive co-management is an approach to the management of ecosystems that is founded on the collaboration of a diverse set of actors as a means of addressing complexity and uncertainty. A key feature is the appreciation of local knowledge systems and social structures which are given equivalent value to conventional scientific and managerial knowledge. This is contrasted with participatory approaches used when confronting the challenges of informal settlements. A demonstration project for the improvement of a street in the informal part of Diepsloot, a settlement on the northern periphery of the City of Johannesburg, was used as a case study to explore aspects of adaptive co-management. A more inclusive approach in urban contexts can nurture initiative and thereby self-respect of marginalised and vulnerable citizens. At the same time, professionals can learn environmental ‘good practice’ from those most knowledgeable about re-use and recycling, and develop an understanding of real urban dynamics.     

Error diffusion in cell-oriented Fourier-transform computer-generated holograms to compensate for printing constraints

Abstract

Error-diffused quantization has been applied to the generation of cell-oriented computer-generated Fourier transform holograms, resulting in reduced reconstruction errors. Improvements are demonstrated when applied to the algorithms of Lohmann, Lee and Burckhardt after invoking realistic constraints on the minimum size of the printable spot for an electrophotographic laser printer.     

Some observations on the bowl phenomenon

Previous studies suggest that performance of a series system may be enhanced if those station(s) having smallest mean operation time requirement(s) and/or smallest variability are placed in the middle of the line. There has been considerable confusion relative to whether this ‘bowl phenomenon’ has to do with the placement of means, variances, or some combination of the two. The results of the current study show that the phenomenon observed is not related to an imbalance in means. Rather, it is associated with an imbalance in absolute variability. Furthermore, it is suggested that the bowl effect vanishes altogether in cases where a minimal level of in-process buffer stock is provided.     

URBAN POLICY,PRESS, AND PLACE: CITY‐MAKING IN FLORIDA'S MIAMI‐DADE COUNTY

This article enhances the notion of city‐making by explicating its communicative processes and functions within the press. Through a quantitative content analysis and qualitative textual analysis of Miami Herald news coverage related to incorporation and annexation policies and practices over a period of 3 years, we argue for a stronger implication of the press in coverage of local policy‐ and place‐making. Through a quantitative content analysis of 437 articles from the Miami Herald about communities affected by incorporation and annexation and a qualitative textual analysis of 51 articles related to general coverage of geographic policy‐making in Miami‐Dade County over a 3‐year period, we argue that this coverage reveals the press as being a central feature and function of policy‐making through the lens of city‐making.     

APPLICATION OF COMPARISON THEOREMS TO DETERMINATION OF THE RESPONSE OF NONLINEAR SYSTEMS

This paper describes methods of obtaining approximate information about the response of nonlinear systems governed by second order differential equations. The solutions of certain related linear equations provide upper and lower bounds on the phase plane for the solution of the corresponding nonlinear equation. Examples are given including a level control system with PI control. The method may be useful in designing controllers for nonlinear systems.     

A NONDESTRUCTIVE METHOD TO MEASURE RESIDUAL ADSORPTION CAPACITY OF CHARCOAL FILTERS

High surface area charcoal bed filters have been used for over a half a century to adsorb undesirable vapors from gas streams. One problem encountered when using these niter beds is that there is presently no simple, reliable, nondestructive method to measure their Residual Adsorption Capacity, RAC. This is particularly critical in situations where harmful vapors are being adsorbed.

An investigation has been underway to use pulses of weakly adsorbed gases such as ethane and/or methane to measure RAC. The hypothesis being that these weakly adsorbed gases will “count” unoccupied adsorption sites. In the present study, dimethyl methylphosphonate (DMMP) was used to “irreversibly” occupy available siles to various extents on different niters. The Reduced Retention Time. θ, (the ratio of the adjusted retention time to the space time) and the Resolution (R) between peaks of methane and ethane were found to correlate to RAC under dry and wet (humid) conditions.     

Endothelin receptor blockade prevents the rise in pulmonary vascular resistance after cardiopulmonary bypass in lambs with increased pulmonary blood flow

BACKGROUND: Children with increased pulmonary blood flow may experience morbidity as the result of increased pulmonary vascular resistance after operations in which cardiopulmonary bypass is used. Plasma levels of endothelin-1, a potent vasoactive substance implicated in pulmonary hypertension, are increased after cardiopulmonary bypass. OBJECTIVES: In a lamb model of increased pulmonary blood flow after in utero placement of an aortopulmonary shunt, we characterized the changes in pulmonary vascular resistance induced by hypothermic cardiopulmonary bypass and investigated the role of endothelin-1 and endothelin-A receptor activation in postbypass pulmonary hypertension. METHODS: In eleven 1-month-old lambs, the shunt was closed, and vascular pressures and blood flows were monitored. An infusion of a selective endothelin-A receptor blocker (PD 156707; 1.0 mg/kg/h) or drug vehicle (saline solution) was then begun 30 minutes before cardiopulmonary bypass and continued for 4 hours after bypass. The hemodynamic variables were monitored, and plasma endothelin-1 concentrations were determined before, during, and for 6 hours after cardiopulmonary bypass. RESULTS: After 90 minutes of hypothermic cardiopulmonary bypass, both pulmonary arterial pressure and pulmonary vascular resistance increased significantly in saline-treated lambs during the 6-hour study period (P <.05). In lambs pretreated with PD 156707, pulmonary arterial pressure and pulmonary vascular resistance decreased (P <. 05). After bypass, plasma endothelin-1 concentrations increased in all lambs; there was a positive correlation between postbypass pulmonary vascular resistance and plasma endothelin-1 concentrations (P <.05). CONCLUSIONS: This study suggests that endothelin-A receptor-induced pulmonary vasoconstriction mediates, in part, the rise in pulmonary vascular resistance after cardiopulmonary bypass. Endothelin-A receptor antagonists may decrease morbidity in children at risk for postbypass pulmonary hypertension. This potential therapy warrants further investigation.     

Inhibition of leukocyte 5-lipoxygenase by phenolics from virgin olive oil

Interest in the health-promoting effects of virgin olive oil, an important part of the 'Mediterranean diet', prompted us to determine the anti-eicosanoid and antioxidant effects in leukocytes of the principal phenolic compounds from the 'polar fraction': oleuropein, tyrosol, hydroxytyrosol, and caffeic acid. In intact rat peritoneal leukocytes stimulated with calcium ionophore, all four phenolics inhibited leukotriene B4 generation at the 5-lipoxygenase level with effectiveness hydroxytyrosol > oleuropein > caffeic acid > tyrosol (approximate EC50 values: 15, 80, 200, and 500 microM, respectively). In contrast, none of these compounds caused substantial inhibition of thromboxane generation via the cyclo-oxygenase pathway. Hydroxytyrosol, caffeic acid, oleuropein, and tyrosol (decreasing order of effectiveness) also quenched the chemiluminescence signal due to reactive oxygen species generated by phorbol myristate acetate-stimulated rat leukocytes. None of these compounds were toxic to leukocytes at the concentrations tested. We conclude that the phenolics found in virgin olive oil possess an array of potentially beneficial lipoxygenase-inhibitory, prostaglandin-sparing, and antioxidant properties.     

The role of CD8 and CD4 T cells in intestinal allograft rejection: a comparison of monoclonal antibody-treated and knockout mice

Studies were performed to determine the effects of PTH and related compounds on phosphatidylcholine (PC) hydrolysis in UMR-106 cells and the pathway by which the PTH effects occurred. The responses were compared with those of phorbol 12,13-dibutyrate (PDBu). Both bovine PTH-(1-34) [bPTH-(1-34)] and PDBu stimulated PC hydrolysis within 10 min. Significant effects were elicited by concentrations of 0.3-1 nM bPTH-(1-34) and 5 nM PDBu. Dose-dependent increases were seen at higher concentrations of both compounds, however, the response to bPTH-(1-34) was reduced at 30 nM. Bovine or human PTH-(1-34) and human PTH-related peptide-(1-34) [hPTHrP-(1-34)] were equipotent in their effects, whereas bovine [Nle(8,18)Tyr34]PTH-(3-34) amide [bPTH-(3-34)] and hPTH-(1-31) amide [hPTH-(1-31)] were less potent than bPTH-(1-34). bPTH-(3-34) did not antagonize the effects of bPTH-(1-34). Down-regulation of protein kinase C isozymes by 24-h treatment with PDBu completely prevented the stimulatory effect of PDBu on PC hydrolysis, but did not significantly affect the stimulatory effect of bPTH-(1-34). Both bPTH-(1-34) and PDBu stimulated transphosphatidylation of PC, indicating a phospholipase D-stimulated mechanism. The results suggest that in the UMR-106 cell line PTH can stimulate activation of PLD by a mechanism other than through protein kinase C.