Metals or Management? Explaining Africa\u27s Recent Economic Growth Spurt

Explanations for Africa\u27s poor long-run growth performance have varied over time. The theories examined include geography (Jeffrey D. Sachs and Andrew Warner 1997); institutions (William Easterly and Ross Levine 1997; Daron Acemoglu, Simon Johnson, and James Robinson 2001, 2002; Nathan Nunn 2007, 2008); health (David Bloom and Sachs 1998; Gregory N. Price 2003); and economic dependency (William Darity 1982). More recently, economists have attempted to explain what The Economist has called Africa\u27s new period of unparalleled economic success (The Economist 2008a, 33). Average annual real GDP growth was 1.8 percent between 1980 and 1989 and increased to 4.4 percent between 2000 and 2005. Per head, real growth in Africa fell by 1.1 percent between 1980 and 1989 and increased 2.1 percent between 2000 and 2005 (World Bank 2007a). This recent reversal of fortune may stem from the broad economic reforms that many African countries instituted during the 1990s, especially macroeconomic stabilization and financial-market liberalization. But it may also be due to the recent boom in international prices of oil, copper, and other primary commodities that constitute a significant fraction of Africa\u27s exports (International Monetary Fund (IMF) 2006). With newly available data extending through 2005, we investigate whether international commodity price increases (our metals hypothesis) or policy reforms (our management hypothesis) have driven Africa\u27s recent performance. In doing so, we supplement existing accounts of Africa\u27s recent success (see Benno J. Ndulu and Stephen A. O\u27Connell 2007; John Page and Jorge S. Arbache 2008, for example). Our results, based on cross-country growth regressions, suggest that both metals and man agement have contributed to Africa\u27s recent reversal of economic fortune

The Idea Gap in Pink and Black

Previous studies have found large gender and racial differences in commercialization of invention. Using novel data that permit enhanced identification of women and African American inventors, we find that gender and racial differences in commercial activity related to invention are lower than once thought. This is despite relatively lower patent activity among women and African Americans. Further, among determinants of commercialization, the evidence suggests that advanced training in engineering is correlated with better commercialization outcomes for women and African Americans than for U.S. inventors as a whole, for whom advanced training in life sciences is more important.

Automatic Filters for the Detection of Coherent Structure in Spatiotemporal Systems

Most current methods for identifying coherent structures in spatially-extended systems rely on prior information about the form which those structures take. Here we present two new approaches to automatically filter the changing configurations of spatial dynamical systems and extract coherent structures. One, local sensitivity filtering, is a modification of the local Lyapunov exponent approach suitable to cellular automata and other discrete spatial systems. The other, local statistical complexity filtering, calculates the amount of information needed for optimal prediction of the system's behavior in the vicinity of a given point. By examining the changing spatiotemporal distributions of these quantities, we can find the coherent structures in a variety of pattern-forming cellular automata, without needing to guess or postulate the form of that structure. We apply both filters to elementary and cyclical cellular automata (ECA and CCA) and find that they readily identify particles, domains and other more complicated structures. We compare the results from ECA with earlier ones based upon the theory of formal languages, and the results from CCA with a more traditional approach based on an order parameter and free energy. While sensitivity and statistical complexity are equally adept at uncovering structure, they are based on different system properties (dynamical and probabilistic, respectively), and provide complementary information.Comment: 16 pages, 21 figures. Figures considerably compressed to fit arxiv requirements; write first author for higher-resolution version

Comparing community-based reading interventions for middle school children with learning disabilities: possible order effects when emphasizing skills or reasoning

IntroductionThere is an abundance of community-based reading programs for school-age children who are struggling learners. The aim of this study was to compare two community-based programs (i.e., skill and reason-based programs) and to analyze any complementary benefits.MethodsIn this randomized cross-over study, 20 children completed two 8-week literacy intervention programs. The skills-based program, Leap to Literacy, focused on explicit teaching and repeated practice of the five key components of literacy instruction (phonemic awareness, phonics, fluency, vocabulary, comprehension). The reason-based program, Wise Words, focused on morphological knowledge, hypothesis testing, and critical thinking.ResultsResults revealed study-wide improvements in phonemic awareness, nonword reading, passage reading accuracy, spelling words and features, and affix identification. There were consistent program by program order effects with robust effects of completing the skills-based program first for phonemic awareness, the reason-based program first for passage reading accuracy, and both programs for affix identification. A significant increase in an oral language measure, recalling sentences, was observed for the group who completed the reason-based program first, although they also started off with a lower initial score.DiscussionFindings indicated improvements from participating in either program. The observed order effects suggest potential additive effects of combining reason- and skills-based approaches to intervention

Normalizing suffering: A meta-synthesis of experiences of and perspectives on pain and pain management in nursing homes

Older people who live in nursing homes commonly suffer from pain. Therefore, relieving suffering among older people thatstems from pain demands knowledge improvement through an integration of international knowledge. This study aimed tointegrate current international findings and strengthen the understanding of older people’s experiences of and perspectiveson pain and pain management in nursing homes. A meta-synthesis study using Noblit and Hare’s interpretative metaethnographyapproach was conducted. Empirical research papers from journals were collected from various databases. Thesearch process and appraisal determined six articles for inclusion. Two studies were conducted in the US and one each inIceland, Norway, the UK, and Australia. The older people’s experiences of pain as well as perspectives on pain managementfrom all involved (older people, their family members, and healthcare staff) were integrated into a theoretical model usingthree themes of ‘‘identity of pain,’’ ‘‘recognition of pain,’’ and ‘‘response to pain.’’ The metaphor of ‘‘normalizing suffering’’was devised to illustrate the meaning of pain experiences and pain management in nursing homes. Society’s commonattitude that pain is unavoidable and therefore acceptable in old age in society*among older people themselves as well asthose who are responsible for reporting, acknowledging, and relieving pain*must change. The article emphasizes that painas a primary source of suffering can be relieved, provided that older people are encouraged to report their pain. In addition,healthcare staff require sufficient training to take a person-centered approach towards assessment and management of painthat considers all elements of pain

Evaluation of chronic lymphocytic leukemia by oligonucleotide-based microarray analysis uncovers novel aberrations not detected by FISH or cytogenetic analysis

<p>Abstract</p> <p>Background</p> <p>Cytogenetic evaluation is a key component of the diagnosis and prognosis of chronic lymphocytic leukemia (CLL). We performed oligonucleotide-based comparative genomic hybridization microarray analysis on 34 samples with CLL and known abnormal karyotypes previously determined by cytogenetics and/or fluorescence <it>in situ </it>hybridization (FISH).</p> <p>Results</p> <p>Using a custom designed microarray that targets >1800 genes involved in hematologic disease and other malignancies, we identified additional cryptic aberrations and novel findings in 59% of cases. These included gains and losses of genes associated with cell cycle regulation, apoptosis and susceptibility loci on 3p21.31, 5q35.2q35.3, 10q23.31q23.33, 11q22.3, and 22q11.23.</p> <p>Conclusions</p> <p>Our results show that microarray analysis will detect known aberrations, including microscopic and cryptic alterations. In addition, novel genomic changes will be uncovered that may become important prognostic predictors or treatment targets for CLL in the future.</p

Practical help for specifying the target difference in sample size calculations for RCTs: the DELTA2 five-stage study, including a workshop

BACKGROUND: The randomised controlled trial is widely considered to be the gold standard study for comparing the effectiveness of health interventions. Central to its design is a calculation of the number of participants needed (the sample size) for the trial. The sample size is typically calculated by specifying the magnitude of the difference in the primary outcome between the intervention effects for the population of interest. This difference is called the 'target difference' and should be appropriate for the principal estimand of interest and determined by the primary aim of the study. The target difference between treatments should be considered realistic and/or important by one or more key stakeholder groups. OBJECTIVE: The objective of the report is to provide practical help on the choice of target difference used in the sample size calculation for a randomised controlled trial for researchers and funder representatives. METHODS: The Difference ELicitation in TriAls2 (DELTA2) recommendations and advice were developed through a five-stage process, which included two literature reviews of existing funder guidance and recent methodological literature; a Delphi process to engage with a wider group of stakeholders; a 2-day workshop; and finalising the core document. RESULTS: Advice is provided for definitive trials (Phase III/IV studies). Methods for choosing the target difference are reviewed. To aid those new to the topic, and to encourage better practice, 10 recommendations are made regarding choosing the target difference and undertaking a sample size calculation. Recommended reporting items for trial proposal, protocols and results papers under the conventional approach are also provided. Case studies reflecting different trial designs and covering different conditions are provided. Alternative trial designs and methods for choosing the sample size are also briefly considered. CONCLUSIONS: Choosing an appropriate sample size is crucial if a study is to inform clinical practice. The number of patients recruited into the trial needs to be sufficient to answer the objectives; however, the number should not be higher than necessary to avoid unnecessary burden on patients and wasting precious resources. The choice of the target difference is a key part of this process under the conventional approach to sample size calculations. This document provides advice and recommendations to improve practice and reporting regarding this aspect of trial design. Future work could extend the work to address other less common approaches to the sample size calculations, particularly in terms of appropriate reporting items. FUNDING: Funded by the Medical Research Council (MRC) UK and the National Institute for Health Research as part of the MRC-National Institute for Health Research Methodology Research programme

Choosing the target difference ('effect size') for a randomised controlled trial - DELTA(2) guidance protocol

BACKGROUND: A key step in the design of a randomised controlled trial (RCT) is the estimation of the number of participants needed. By far the most common approach is to specify a target difference and then estimate the corresponding sample size; this sample size is chosen to provide reassurance that the trial will have high statistical power to detect such a difference between the randomised groups (at the planned statistical significance level). The sample size has many implications for the conduct of the study, as well as carrying scientific and ethical aspects to its choice. Despite the critical role of the target difference for the primary outcome in the design of an RCT, the manner in which it is determined has received little attention. This article reports the protocol of the Difference ELicitation in TriAls (DELTA(2)) project, which will produce guidance on the specification and reporting of the target difference for the primary outcome in a sample size calculation for RCTs. METHODS/DESIGN: The DELTA(2) project has five components: systematic literature reviews of recent methodological developments (stage 1) and existing funder guidance (stage 2); a Delphi study (stage 3); a 2-day consensus meeting bringing together researchers, funders and patient representatives, as well as one-off engagement sessions at relevant stakeholder meetings (stage 4); and the preparation and dissemination of a guidance document (stage 5). DISCUSSION: Specification of the target difference for the primary outcome is a key component of the design of an RCT. There is a need for better guidance for researchers and funders regarding specification and reporting of this aspect of trial design. The aim of this project is to produce consensus based guidance for researchers and funders