293 research outputs found

    Economic valuation of forests and nature : a support tool for effective decision making

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    Included are several case studies, like: The Leuser ecosystem, Sumatra; The Borivili National Park, India; Tropical rain forests, Costa Rica; Mangrove forests, Philippines. This document has been prepared by: IAC and EC-LN

    Determinants of survival in very low birth weight neonates in a public sector hospital in Johannesburg

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    <p>Abstract</p> <p>Background</p> <p>Audit of disease and mortality patterns provides essential information for health budgeting and planning, as well as a benchmark for comparison. Neonatal mortality accounts for about 1/3 of deaths < 5 years of age and very low birth weight (VLBW) mortality for approximately 1/3 of neonatal mortality. Intervention programs must be based on reliable statistics applicable to the local setting; First World data cannot be used in a Third World setting. Many neonatal units participate in the Vermont Oxford Network (VON); limited resources prevent a significant number of large neonatal units from developing countries taking part, hence data from such units is lacking. The purpose of this study was to provide reliable, recent statistics relevant to a developing African country, useful for guiding neonatal interventions in that setting.</p> <p>Methods</p> <p>This was a retrospective chart review of 474 VLBW infants admitted within 24 hours of birth, between 1 July 2006 and 30 June 2007, to the neonatal unit of Charlotte Maxeke Johannesburg Academic Hospital (CMJAH) in Johannesburg, South Africa. Binary outcome logistic regression on individual variables and multiple logistic regression was done to identify those factors determining survival.</p> <p>Results</p> <p>Overall survival was 70.5%. Survival of infants below 1001 grams birth weight was 34.9% compared to 85.8% for those between 1001 and 1500 grams at birth. The main determinant of survival was birth weight with an adjusted survival odds ratio of 23.44 (95% CI: 11.22 - 49.00) for babies weighing between 1001 and 1500 grams compared to those weighing below 1001 grams. Other predictors of survival were gender (OR 3. 21; 95% CI 1.6 - 6.3), birth before arrival at the hospital (BBA) (OR 0.23; 95% CI: 0.08 - 0.69), necrotising enterocolitis (NEC) (OR 0.06; 95% CI: 0.02 - 0.20), hypotension (OR 0.05; 95% CI 0.01 - 0.21) and nasal continuous positive airways pressure (NCPAP) (OR 4.58; 95% CI 1.58 - 13.31).</p> <p>Conclusions</p> <p>Survival rates compare favourably with other developing countries, but can be improved; especially in infants < 1001 grams birth weight. Resources need to be allocated to preventing the birth of VLBW babies outside hospital, early neonatal resuscitation, provision of NCPAP and prevention of NEC.</p

    High School Students' Proficiency and Confidence Levels in Displaying Their Understanding of Basic Electrolysis Concepts

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    This study was conducted with 330 Form 4 (grade 10) students (aged 15 – 16 years) who were involved in a course of instruction on electrolysis concepts. The main purposes of this study were (1) to assess high school chemistry students’ understanding of 19 major principles of electrolysis using a recently developed 2-tier multiple-choice diagnostic instrument, the Electrolysis Diagnostic Instrument (EDI), and (2) to assess students’ confidence levels in displaying their knowledge and understanding of these electrolysis concepts. Analysis of students’ responses to the EDI showed that they displayed very limited understanding of the electrolytic processes involving molten compounds and aqueous solutions of compounds, with a mean score of 6.82 (out of a possible maximum of 17). Students were found to possess content knowledge about several electrolysis processes but did not provide suitable explanations for the changes that had occurred, with less than 45 % of students displaying scientifically acceptable understandings about electrolysis. In addition, students displayed limited confidence about making the correct selections for the items; yet, in 16 of the 17 items, the percentage of students who were confident that they had selected the correct answer to an item was higher than the actual percentage of students who correctly answered the corresponding item. The findings suggest several implications for classroom instruction on the electrolysis topic that need to be addressed in order to facilitate better understanding by students of electrolysis concepts

    Accumulation of Phosphorylated β-Catenin Enhances ROS-Induced Cell Death in Presenilin-Deficient Cells

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    Presenilin (PS) is involved in many cellular events under physiological and pathological conditions. Previous reports have revealed that PS deficiency results in hyperproliferation and resistance to apoptotic cell death. In the present study, we investigated the effects of PS on β-catenin and cell mortality during serum deprivation. Under these conditions, PS1/PS2 double-knockout MEFs showed aberrant accumulation of phospho-β-catenin, higher ROS generation, and notable cell death. Inhibition of β-catenin phosphorylation by LiCl reversed ROS generation and cell death in PS deficient cells. In addition, the K19/49R mutant form of β-catenin, which undergoes normal phosphorylation but not ubiquitination, induced cytotoxicity, while the phosphorylation deficient S37A β-catenin mutant failed to induce cytotoxicity. These results indicate that aberrant accumulation of phospho-β-catenin underlies ROS-mediated cell death in the absence of PS. We propose that the regulation of β-catenin is useful for identifying therapeutic targets of hyperproliferative diseases and other degenerative conditions

    Delirium risk screening and haloperidol prophylaxis program in hip fracture patients is a helpful tool in identifying high-risk patients, but does not reduce the incidence of delirium

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    Background: Delirium in patients with hip fractures lead to higher morbidity and mortality. Prevention in high-risk patients by prescribing low dose haloperidol is currently under investigation. Methods. This prospective cohort surveillance assessed hip fracture patients for risk of developing a delirium with the Risk Model for Delirium (RD) score. High-risk patients (score ≥5 points) were treated with a prophylactic low-dose of haloperidol according to hospital protocol. Primary outcome was delirium incidence. Secondary outcomes were differences between high- and low-risk patients in delirium, length of stay (LOS), return to pre-fracture living situation and mortality. Logistic regression analysis was performed with age, ASA-classification, known dementia, having a partner, type of fracture, institutional residence and psychotropic drug use as possible confounders. Results: 445 hip fracture patients aged 65 years and older were admitted from January 2008 to December 2009. The RD-score was completed in 378 patients, 173 (45.8%) high-risk patients were treated with prophylactic medication. Sensitivity was 71.6%, specificity 63.8% and the negative predictive value (NPV) of a score < 5 was 85.9%. Delirium incidence (27.0%) was not significantly different compared to 2007 (27.8%) 2006 (23.9%) and 2005 (29.0%) prior to implementation of the RD- protocol. Logistic regression analysis showed that high-risk patients did have a significant higher delirium incidence (42.2% vs. 14.1%, OR 4.1, CI 2.43-7.02). They were more likely to be residing at an alternative living situation after 3 months (62.3% vs. 17.0%, OR 6.57, CI 3.23-13.37) and less likely to be discharged from hospital before 10 days (34.9% vs. 55.9%, OR 1.63, CI 1.03-2.59). Significant independent risk factors for a delirium were a RD-score 5 (OR 4.13, CI 2.43-7.02), male gender (OR 1.93, CI 0.99-1.07) and age (OR 1.03, CI 0.99-1.07). Conclusions: Introducing the delirium prevention protocol did not reduce delirium incidence. The RD-score did identify patients with a high risk to develop a delirium. This high-risk group had a longer LOS and returned to pre-fracture living situation less often. The NPV of a score < 5 was high, as it should be for a screening instrument. Concluding, the RD-score is a useful tool to identify patients with poorer outcome

    Reversal of stress fibre formation by Nitric Oxide mediated RhoA inhibition leads to reduction in the height of preformed thrombi

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    Evidence has emerged to suggest that thrombi are dynamic structures with distinct areas of differing platelet activation and inhibition. We hypothesised that Nitric oxide (NO), a platelet inhibitor, can modulate the actin cytoskeleton reversing platelet spreading, and therefore reduce the capability of thrombi to withstand a high shear environment. Our data demonstrates that GSNO, DEANONOate, and a PKG-activating cGMP analogue reversed stress fibre formation and increased actin nodule formation in adherent platelets. This effect is sGC dependent and independent of ADP and thromboxanes. Stress fibre formation is a RhoA dependent process and NO induced RhoA inhibition, however, it did not phosphorylate RhoA at ser188 in spread platelets. Interestingly NO and PGI2 synergise to reverse stress fibre formation at physiologically relevant concentrations. Analysis of high shear conditions indicated that platelets activated on fibrinogen, induced stress fibre formation, which was reversed by GSNO treatment. Furthermore, preformed thrombi on collagen post perfused with GSNO had a 30% reduction in thrombus height in comparison to the control. This study demonstrates that NO can reverse key platelet functions after their initial activation and identifies a novel mechanism for controlling excessive thrombosis

    Current debates in urban theory: a critical assessment

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    Urban studies today is marked by many active debates. In an earlier paper, we addressed some of these debates by proposing a foundational concept of urbanization and urban form as a way of identifying a common language for urban research. In the present paper we provide a brief recapitulation of that framework. We then use this preliminary material as background to a critique of three currently influential versions of urban analysis, namely, postcolonial urban theory, assemblage theoretic approaches, and planetary urbanism. We evaluate each of these versions in turn and find them seriously wanting as statements about urban realities. We criticize (a) postcolonial urban theory for its particularism and its insistence on the provincialization of knowledge, (b) assemblage theoretic approaches for their indeterminacy and eclecticism, and (c) planetary urbanism for its radical devaluation of the forces of agglomeration and nodality in urban-economic geography

    Burden-driven feedback control of gene expression

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    Cells use feedback regulation to ensure robust growth despite fluctuating demands for resources and differing environmental conditions. However, the expression of foreign proteins from engineered constructs is an unnatural burden that cells are not adapted for. Here we combined RNA-seq with an in vivo assay to identify the major transcriptional changes that occur in Escherichia coli when inducible synthetic constructs are expressed. We observed that native promoters related to the heat-shock response activated expression rapidly in response to synthetic expression, regardless of the construct. Using these promoters, we built a dCas9-based feedback-regulation system that automatically adjusts the expression of a synthetic construct in response to burden. Cells equipped with this general-use controller maintained their capacity for native gene expression to ensure robust growth and thus outperformed unregulated cells in terms of protein yield in batch production. This engineered feedback is to our knowledge the first example of a universal, burden-based biomolecular control system and is modular, tunable and portable
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