Market structure, Regulation and the Speed of Mobile Network Penetration

The speed of market penetration (i.e. diffusion) is an important summary measure of how well the market works for potential consumers of a new product. This paper identifies the structural features associated with rapid diffusion of mobile telephony. We use a sample of thirty countries over the sixteen years in which average penetration rose from 2% to 97% of the population (earlier studies observed only the initial years of diffusion during which there was typically only one or two networks). We find a non-monotonic effect of market structure, with three firms maximising consumer uptake. Privatization and independent regulation are also important positive factors. Further results show that the market structure effect works only partially through the level of prices

Facing the rain after the phase out : Performance evaluation of alternative fluorinated and non-fluorinated durable water repellents for outdoor fabrics

Fluorinated durable water repellent (DWR) agents are used to obtain water and stain repellent textiles. Due to the on-going phase-out of DWRs based on side-chain fluorinated polymers (SFP) with “long” perfluoroalkyl chains, the textile industry lacks suitable alternatives with comparable material characteristics. The constant development and optimization of SFPs for textile applications initiated more than half a century ago has resulted in a robust and very efficient DWR-technology and textiles with exceptional hydro- and oleo-phobic properties. The industry is now in the predicament that the long-chain SFPs with the best technical performance have undesirable toxicological and environmental behaviour. This study provides a comprehensive overview of the technical performance of presently available fluorinated and non-fluorinated DWRs as part of a chemical alternatives assessment (CAA). The results are based on a study with synthetic outdoor fabrics treated with alternative DWRs and tested for repellency using industrial standard and complementary methods. Using this approach, the complex structure-property relationships of DWR-polymers could be explained on a molecular level. Both short-chain SFPs and non-fluorinated DWRs showed excellent water repellency and durability in some cases while short-chain SFPs were the more robust of the alternatives to long-chain SFPs. A strong decline in oil repellency and durability with perfluoroalkyl chain length was shown for SFP DWRs. Non-fluorinated alternatives were unable to repel oil, which might limit their potential for substitution in textile application that require repellency towards non-polar liquids

Stem cell treatment for acute myocardial infarction

BACKGROUND: Stem cell therapy offers a promising approach to the regeneration of damaged vascular and cardiac tissue after acute myocardial infarction (AMI). This has resulted in multiple randomised controlled trials (RCTs) worldwide. OBJECTIVES: To critically evaluate evidence from RCTs on the effectiveness of adult bone marrow-derived stem cells (BMSC) to treat acute myocardial infarction (AMI). SEARCH METHODS: This Cochrane review is an update of a previous one (published in 2008). MEDLINE (1950 to January 2011), EMBASE (1974 to January 2011), the Cochrane Central Register of Controlled Trials (CENTRAL) (Issue 1, 2011), CINAHL (1982 to January 2011) and the Transfusion Evidence Library (1980 to January 2011) were searched. In addition, several international and ongoing trial databases were searched and handsearching of relevant conference proceedings undertaken to January 2011. SELECTION CRITERIA: RCTs comparing autologous stem/progenitor cells with no autologous stem/progenitor cells in patients diagnosed with AMI were eligible. DATA COLLECTION AND ANALYSIS: Two authors independently screened all references, assessed trial quality and extracted data. Meta-analyses using a random-effects model were conducted and heterogeneity was explored for the primary outcome using sub-group analyses. MAIN RESULTS: Thirty-three RCTs (1765 participants) were eligible for inclusion. Stem/progenitor cell treatment was not associated with statistically significant changes in the incidence of mortality (RR 0.70, 95% CI 0.40 to 1.21) or morbidity (the latter measured by re-infarction, hospital re-admission, restenosis and target vessel revascularisation). A considerably high degree of heterogeneity has been observed among the included trials. In short-term follow up, stem cell treatment was observed to improve left ventricular ejection fraction (LVEF) significantly (WMD 2.87, 95% CI 2.00 to 3.73). This improvement in LVEF was maintained over long-term follow up of 12 to 61 months (WMD 3.75, 95% CI 2.57 to 4.93). With certain measurements and at certain times, stem cell treatment was observed to reduce left ventricular end systolic and end diastolic volumes (LVESV and LVEDV) and infarct size significantly in long-term follow up. There was a positive correlation between mononuclear cell dose infused and the effect on LVEF measured by magnetic resonance imaging. A correlation between timing of stem cell treatment and effect on LVEF measured by left ventricular angiography was also observed. AUTHORS' CONCLUSIONS: Despite the high degree of heterogeneity observed, the results of this systematic review suggest that moderate improvement in global heart function is significant and sustained long-term. However, because mortality rates after successful revascularization of the culprit arteries are very low, larger number of participants would be required to assess the full clinical effect of this treatment. Standardisation of methodology, cell dosing and cell product formulation, timing of cell transplantation and patient selection may also be required in order to reduce the substantial heterogeneity observed among the included studies