Spatial heterogeneity enhances and modulates excitability in a mathematical model of the myometrium

The muscular layer of the uterus (myometrium) undergoes profound changes in global excitability prior to parturition. Here, a mathematical model of the myocyte network is developed to investigate the hypothesis that spatial heterogeneity is essential to the transition from local to global excitation which the myometrium undergoes just prior to birth. Each myometrial smooth muscle cell is represented by an element with FitzHugh–Nagumo dynamics. The cells are coupled through resistors that represent gap junctions. Spatial heterogeneity is introduced by means of stochastic variation in coupling strengths, with parameters derived from physiological data. Numerical simulations indicate that even modest increases in the heterogeneity of the system can amplify the ability of locally applied stimuli to elicit global excitation. Moreover, in networks driven by a pacemaker cell, global oscillations of excitation are impeded in fully connected and strongly coupled networks. The ability of a locally stimulated cell or pacemaker cell to excite the network is shown to be strongly dependent on the local spatial correlation structure of the couplings. In summary, spatial heterogeneity is a key factor in enhancing and modulating global excitability

Teacher Reform in Indonesia: The Role of Politics and Evidence in Policy Making

Teacher Reform in Indonesia: The Role of Politics and Evidence in Policy Making is the result of seven years of collaborative effort between the Human Development Sector of the World Bank Indonesia country office and the Government of Indonesia. The Human Development Sector, led by Mae Chu Chang, produced over 50 independent background papers by Bank staff, government researchers, and international consultants, as well several major research projects including an impact evaluation and in-depth classroom observations. This synthesis report was prepared under the team leadership of Mae Chu Chang and included as mem- bers Samer Al-Samarrai, Andrew Ragatz, Joppe de Ree, Sheldon Shaeffer, and Ritchie Stevenson (co-authors) as well as Rina Arlianti, Susiana Iskandar, and Titie Hadiyati (contributors). Research assistance was provided by Shahnaz Arina, Megha Kapoor, Imam Setiawan, and Susie Sugiarti. Mary Anderson provided editorial support, and the graphic designer was Yvonne Armanto Ramali. \ud The production of this report, as well as the variety of research studies con- ducted over the past seven years on which the book is based, was generously supported by the Dutch Education Support Program (DESP) funded by the Government of the Kingdom of the Netherlands. The team is indebted to Arnold Vander Zanden (First Secretary Education, Royal Netherlands Embassy, Indonesia) for his strong support throughout the years for demand-driven and “just-in-time” policy work that has been carried out under DESP. Technical con- tributions from AusAID-supported consultants, Graham Dawson and John Bladen, are also acknowledged. \ud It should be noted that although inputs of various officials have been incorpo- rated into the report, the policy recommendations in this document do not necessarily reflect the policies of the Government of Indonesia, the Government of the Kingdom of the Netherlands, or the World Bank. \ud The team of authors who produced this report is grateful to the officials and staff of the Ministry of Education and Culture for their overall support. Special thanks are in order to Fasli Jalal, former Vice Minister of Education, who was the visionary behind the Teacher Law that inspired this report and a key supporter of many of the teacher management studies that contributed to it. The current Minister of Education and Culture, Mohammad Nuh; Vice Minister of Education, Musliar Kasim; the Special Advisor to the Minister, Taufik Hanafi; the Head of \ud the Board of Education and Culture, Human Resources Development and Quality Assurance for Education, Syawal Gultom; and the former Director General for Quality Improvement of Teacher and Education Personnel, Baedhowi, played major roles in using the evidence produced to improve the teacher regula- tions. The report also benefited greatly from the inputs of the Ministry of Religious Affairs, the National Development Planning Agency, the Ministry of State Administration Reform, the Ministry of Finance, and the Civil Service Agency, together with inputs of donor agencies that were received during various consultation meetings and policy forum discussions. Key government support came from the directors, the head of centers, and senior key staff of the Ministry responsible for teacher management, quality assurance, and teacher-related stud- ies: Sumarna Suryapranata, Surya Dharma, Hendarman, Unifah Rosyidi, Abi Sujak, Muchlas Samani, Anah Suhaenah, Gogot Suharwoto, Maria Widiani, Poppy Puspitawati, Dian Wahyuni, Santi Ambarukmi, E. Nurzaman, Giri Suryaatmana, Ahmad Dasuki, Bambang Indriyanto, Nugaan Yulia Wardhani Siregar, Hari Setiadi, Burhanudin Tola, Yendri Wirda Burhan, Simon Sili Sabon, Rahmawati, Handayani Sumarno, Rumtini, Yaya Zakaria, and M.S. Sembiring. \ud Insightful comments from stakeholders were provided by Lilian Rahman (Gorontalo district), Sulistiyo (Chair of the Teacher Association of Republic of Indonesia, PGRI), Sahiri Hermawan (PGRI), Arief Rahman (Chair of the Indonesian National Commission for UNESCO), Heri Akhmadi (a member of Parliament), Anies Baswedan (Rector of Paramadina University and Chair of Indonesia Mengajar), Hetty Herawati (Principal of SD Taruna Bangsa), Sudarwan Danim and Anthony Crocker (consultants at the Board of Education and Culture, Human Resources Development and Quality Assurance for Education), Agus Supriatman (Head of the Education Office, Karawang District), Nanda Suhanda (a member of the Karawang District Parliament), Obang Nurbayu (Head of PGRI, Karawang District), and Nanang Muchlis (Chair, Board of Education, Karawang District). \ud The report was improved by detailed feedback from the following principal reviewers: F. Halsey Rogers, Venkatesh Sundararaman, and Helen J. Craig (World Bank); Molly Lee (formerly UNESCO); and Tom Lowrie (Charles Sturt University). Helpful comments were also received from William Wallace, James A. Brumby, and Yasuhiko Matsuda (World Bank). The report was prepared under the guidance of Luis Benveniste, Sector Manager, East Asia and Pacific Region, and the support of Stefan Koeberle (Country Director for Indonesia)

Implantable cardioverter defibrillators for the treatment of arrhythmias and cardiac resynchronisation therapy for the treatment of heart failure: systematic review and economic evaluation

Background This assessment updates and expands on two previous technology assessments that evaluated implantable cardioverter defibrillators (ICDs) for arrhythmias and cardiac resynchronisation therapy (CRT) for heart failure (HF). Objectives To assess the clinical effectiveness and cost-effectiveness of ICDs in addition to optimal pharmacological therapy (OPT) for people at increased risk of sudden cardiac death (SCD) as a result of ventricular arrhythmias despite receiving OPT; to assess CRT with or without a defibrillator (CRT-D or CRT-P) in addition to OPT for people with HF as a result of left ventricular systolic dysfunction (LVSD) and cardiac dyssynchrony despite receiving OPT; and to assess CRT-D in addition to OPT for people with both conditions. Data sources Electronic resources including MEDLINE, EMBASE and The Cochrane Library were searched from inception to November 2012. Additional studies were sought from reference lists, clinical experts and manufacturers’ submissions to the National Institute for Health and Care Excellence. Review methods Inclusion criteria were applied by two reviewers independently. Data extraction and quality assessment were undertaken by one reviewer and checked by a second. Data were synthesised through narrative review and meta-analyses. For the three populations above, randomised controlled trials (RCTs) comparing (1) ICD with standard therapy, (2) CRT-P or CRT-D with each other or with OPT and (3) CRT-D with OPT, CRT-P or ICD were eligible. Outcomes included mortality, adverse events and quality of life. A previously developed Markov model was adapted to estimate the cost-effectiveness of OPT, ICDs, CRT-P and CRT-D in the three populations by simulating disease progression calculated at 4-weekly cycles over a lifetime horizon. Results A total of 4556 references were identified, of which 26 RCTs were included in the review: 13 compared ICD with medical therapy, four compared CRT-P/CRT-D with OPT and nine compared CRT-D with ICD. ICDs reduced all-cause mortality in people at increased risk of SCD, defined in trials as those with previous ventricular arrhythmias/cardiac arrest, myocardial infarction (MI) > 3 weeks previously, non-ischaemic cardiomyopathy (depending on data included) or ischaemic/non-ischaemic HF and left ventricular ejection fraction ≤ 35%. There was no benefit in people scheduled for coronary artery bypass graft. A reduction in SCD but not all-cause mortality was found in people with recent MI. Incremental cost-effectiveness ratios (ICERs) ranged from £14,231 per quality-adjusted life-year (QALY) to £29,756 per QALY for the scenarios modelled. CRT-P and CRT-D reduced mortality and HF hospitalisations, and improved other outcomes, in people with HF as a result of LVSD and cardiac dyssynchrony when compared with OPT. The rate of SCD was lower with CRT-D than with CRT-P but other outcomes were similar. CRT-P and CRT-D compared with OPT produced ICERs of £27,584 per QALY and £27,899 per QALY respectively. The ICER for CRT-D compared with CRT-P was £28,420 per QALY. In people with both conditions, CRT-D reduced the risk of all-cause mortality and HF hospitalisation, and improved other outcomes, compared with ICDs. Complications were more common with CRT-D. Initial management with OPT alone was most cost-effective (ICER £2824 per QALY compared with ICD) when health-related quality of life was kept constant over time. Costs and QALYs for CRT-D and CRT-P were similar. The ICER for CRT-D compared with ICD was £27,195 per QALY and that for CRT-D compared with OPT was £35,193 per QALY. Limitations Limitations of the model include the structural assumptions made about disease progression and treatment provision, the extrapolation of trial survival estimates over time and the assumptions made around parameter values when evidence was not available for specific patient groups. Conclusions In people at risk of SCD as a result of ventricular arrhythmias and in those with HF as a result of LVSD and cardiac dyssynchrony, the interventions modelled produced ICERs of < £30,000 per QALY gained. In people with both conditions, the ICER for CRT-D compared with ICD, but not CRT-D compared with OPT, was < £30,000 per QALY, and the costs and QALYs for CRT-D and CRT-P were similar. A RCT comparing CRT-D and CRT-P in people with HF as a result of LVSD and cardiac dyssynchrony is required, for both those with and those without an ICD indication. A RCT is also needed into the benefits of ICD in non-ischaemic cardiomyopathy in the absence of dyssynchrony. Study registration This study is registered as PROSPERO number CRD42012002062. Funding The National Institute for Health Research Health Technology Assessment programme

Adam Smith’s Green Thumb and Malthus’ Three Horsemen: Cautionary tales from classical political economy

This essay identifies a contradiction between the flourishing interest in the environmental economics of the classical period and a lack of critical parsing of the works of its leading representatives. Its focus is the work of Adam Smith and Thomas Malthus. It offers a critical analysis of their contribution to environmental thought and surveys the work of their contemporary devotees. It scrutinizes Smith's contribution to what Karl Polanyi termed the "economistic fallacy," as well as his defenses of class hierarchy, the "growth imperative" and consumerism. It subjects to critical appraisal Malthus's enthusiasm for private property and the market system, and his opposition to market regulation. While Malthus's principal attraction to ecological economists lies in his having allegedly broadened the scope of economics, and in his narrative of scarcity, this article shows that he, in fact, narrowed the scope of the discipline and conceptualized scarcity in a reified and pseudo-scientific way

Do female association preferences predict the likelihood of reproduction?

Sexual selection acting on male traits through female mate choice is commonly inferred from female association preferences in dichotomous mate choice experiments. However, there are surprisingly few empirical demonstrations that such association preferences predict the likelihood of females reproducing with a particular male. This information is essential to confirm association preferences as good predictors of mate choice. We used green swordtails (&lt;i&gt;Xiphophorus helleri&lt;/i&gt;) to test whether association preferences predict the likelihood of a female reproducing with a male. Females were tested for a preference for long- or short-sworded males in a standard dichotomous choice experiment and then allowed free access to either their preferred or non-preferred male. If females subsequently failed to produce fry, they were provided a second unfamiliar male with similar sword length to the first male. Females were more likely to reproduce with preferred than non-preferred males, but for those that reproduced, neither the status (preferred/non-preferred) nor the sword length (long/short) of the male had an effect on brood size or relative investment in growth by the female. There was no overall preference based on sword length in this study, but male sword length did affect likelihood of reproduction, with females more likely to reproduce with long- than short-sworded males (independent of preference for such males in earlier choice tests). These results suggest that female association preferences are good indicators of female mate choice but that ornament characteristics of the male are also important

Implications Of Mixed Results With Cointegration Models In International Studies

While cointegration models have been used extensively in many fields (such as in testing for stock market predictability), there have been mixed results from using cointegration models in international studies.&nbsp; For example, one study attempted to regress the levels of the general stock market price indexes of Norway, Mexico, Venezuela, and of Oman on the levels of interest rate and oil prices variables during the period 1992 to 1999.&nbsp; Attempts to explain mixed results have included distinguishing developed markets versus less developed markets and differences in the volatilities of markets. Another approach has been attempts to improve cointegration methods.&nbsp; Some studies have included both bivariate and multivariate methods of cointegration.&nbsp; Others have employed augmented Dickey-Fuller unit root tests of the residuals.&nbsp; The extent of mixed results in international studies has implications for earlier studies in single countries.&nbsp; It is possible that many earlier studies in business and in economics will need to be replicated using newer techniques developed by international researchers.&nbsp; The purpose of this study is to explain the attempts to improve cointegration methods, the mixed results in international studies, and the implications for earlier studies relying upon cointegration models

Oxidation behaviour of SiC/SiC ceramic matrix composites in air

Oxidation of silicon melt infiltrated SiC/SiC ceramic matrix composites (CMC) was studied in air at 1200–1400 °C for 1, 5, 24 and 48 h. Weight gain and oxide layer thickness measurements revealed the oxidation follows parabolic reaction kinetics with increase in temperature and time. XRD showed the extent of oxide layer (SiO2) formation was greatest after 48 h at 1400 °C: an observation confirmed by X-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDS) and transmission electron microscopy (TEM) analyses. Oxide layer thickness varied from 1 μm after 48 h at 1200 °C to 8 μm after 48 h at 1400 °C. Oxidation of SiC/SiC composites is both temperature and time dependent with an activation energy of 619 kJ mol−1. BN coatings around SiC fibres showed good resistance to oxidation even after 48 h at 1400 °C

A survey of performance enhancement of transmission control protocol (TCP) in wireless ad hoc networks

This Article is provided by the Brunel Open Access Publishing Fund - Copyright @ 2011 Springer OpenTransmission control protocol (TCP), which provides reliable end-to-end data delivery, performs well in traditional wired network environments, while in wireless ad hoc networks, it does not perform well. Compared to wired networks, wireless ad hoc networks have some specific characteristics such as node mobility and a shared medium. Owing to these specific characteristics of wireless ad hoc networks, TCP faces particular problems with, for example, route failure, channel contention and high bit error rates. These factors are responsible for the performance degradation of TCP in wireless ad hoc networks. The research community has produced a wide range of proposals to improve the performance of TCP in wireless ad hoc networks. This article presents a survey of these proposals (approaches). A classification of TCP improvement proposals for wireless ad hoc networks is presented, which makes it easy to compare the proposals falling under the same category. Tables which summarize the approaches for quick overview are provided. Possible directions for further improvements in this area are suggested in the conclusions. The aim of the article is to enable the reader to quickly acquire an overview of the state of TCP in wireless ad hoc networks.This study is partly funded by Kohat University of Science & Technology (KUST), Pakistan, and the Higher Education Commission, Pakistan

Performance of the CMS Cathode Strip Chambers with Cosmic Rays

The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device in the CMS endcaps. Their performance has been evaluated using data taken during a cosmic ray run in fall 2008. Measured noise levels are low, with the number of noisy channels well below 1%. Coordinate resolution was measured for all types of chambers, and fall in the range 47 microns to 243 microns. The efficiencies for local charged track triggers, for hit and for segments reconstruction were measured, and are above 99%. The timing resolution per layer is approximately 5 ns

Atmospheric Evolution

Earth's atmosphere has evolved as volatile species cycle between the atmosphere, ocean, biomass and the solid Earth. The geochemical, biological and astrophysical processes that control atmospheric evolution are reviewed from an "Earth Systems" perspective, with a view not only to understanding the history of Earth, but also to generalizing to other solar system planets and exoplanets.Comment: 34 pages, 3 figures, 2 tables. Accepted as a chapter in "Encyclopaedia of Geochemistry", Editor Bill White, Springer-Nature, 201