Diffusion imaging is critical for detecting acute brain injury. However, normal apparent diffusion coefficient (ADC) maps change rapidly in early childhood, making abnormality detection difficult. In this article, we explored clinical PACS and electronic healthcare records (EHR) to create age-specific ADC atlases for clinical radiology reference. Using the EHR and three rounds of multiexpert reviews, we found ADC maps from 201 children 0-6 years of age scanned between 2006 and 2013 who had brain MRIs with no reported abnormalities and normal clinical evaluations 2+ years later. These images were grouped in 10 age bins, densely sampling the first 1 year of life (5 bins, including neonates and 4 quarters) and representing the 1-6 year age range (an age bin per year). Unbiased group-wise registration was used to construct ADC atlases for 10 age bins. We used the atlases to quantify (a) cross-sectional normative ADC variations; (b) spatiotemporal heterogeneous ADC changes; and (c) spatiotemporal heterogeneous volumetric changes. The quantified age-specific whole-brain and region-wise ADC values were compared to those from age-matched individual subjects in our study and in multiple existing independent studies. The significance of this study is that we have shown that clinically acquired images can be used to construct normative age-specific atlases. These first of their kind age-specific normative ADC atlases quantitatively characterize changes of myelination-related water diffusion in the first 6 years of life. The quantified voxel-wise spatiotemporal ADC variations provide standard references to assist radiologists toward more objective interpretation of abnormalities in clinical images. Our atlases are available at https://www.nitrc.org/projects/mgh_adcatlases.
Writing in the 1990’s, William Easterly and Ross Levine famously labeled Africa a “growth tragedy”.1 Less than twenty years later, Alwyn Young noted Africa’s “growth miracle”2, while Steven Radelet less effusively pointed to an Africa that was “emerging” and noted its rising rate of economic growth, improving levels of education and health care, and increasing levels of investment in basic infrastructure: roads, ports, and transport3. In this paper, we address Africa’s economic revival. In doing so, we also stress the political changes that have taken place on the continent. Once notorious for its tyrants – Jean-‐Bedel Bokassa, Idi Amin, and Mobutu Sese Seko, to name but three – in the 1990s, Africa joined the last wave of democratization; self-‐appointed heads of state were replaced by rulers chosen in competitive elections. In this paper, we assert that the two sets of changes – the one economic and the other political – go together, and that, indeed, changes in Africa’s political institutions lent significant impetus to its economic revival.
This edited volume addresses the root causes of Africa’s persistent poverty through an investigation of its longue durée history. It interrogates the African past through disease and demography, institutions and governance, African economies and the impact of the export slave trade, colonialism, Africa in the world economy, and culture’s influence on accumulation and investment. Several of the chapters take a comparative perspective, placing Africa’s developments aside other global patterns. The readership for this book spans from the informed lay reader with an interest in Africa, academics and undergraduate and graduate students, policy makers, and those in the development world.
Recent studies reveal that the bacterial nucleoid has a defined, self-adherent shape and an underlying longitudinal organization and comprises a viscoelastic matrix. Within this shape, mobility is enhanced by ATP-dependent processes and individual loci can undergo ballistic off-equilibrium movements. In Escherichia coli, two global dynamic nucleoid behaviors emerge pointing to nucleoid-wide accumulation and relief of internal stress. Sister segregation begins with local splitting of individual loci, which is delayed at origin, terminus and specialized interstitial snap regions. Globally, as studied in several systems, segregation is a multi-step process in which internal nucleoid state plays critical roles that involve both compaction and expansion. The origin and terminus regions undergo specialized programs partially driven by complex ATP burning mechanisms such as a ParAB Brownian ratchet and a septum-associated FtsK motor. These recent findings reveal strong, direct parallels among events in different systems and between bacterial nucleoids and mammalian chromosomes with respect to physical properties, internal organization and dynamic behaviors.
People speak of an “African renaissance.” We report and explore data that suggest that the continent’s return to positive growth can near entirely be explained by changes in total factor productivity growth. We find as well that changes in Africa’s political institutions played a major role in this transition and that the channel linking institutional change to changes in economic performance runs in significant part through changes in policy choices. We conclude with reasons to be cautious in assessments of the depth and durability of the changes in Africa’s economies.
When praised at all, imperialism is most often commended for the peace it bestowed. By demobilizing armies, deposing marauding princes and subduing war-like states, European powers fashioned a half-century of political order. The question nonetheless arises: Should they be lauded for that? In this chapter, I view Africa’s history through the lens of comparative history and argue that the imperial peace may have retarded Africa’s development.
We revisit Lipset’s law, which posits a positive and significant relationship between income and democracy. Using dynamic and heterogeneous panel data estimation techniques, we find a significant and negative relationship between income and democracy: higher/lower incomes per capita hinder/trigger democratization. We thus challenge the recent empirical literature that found no such significant relationship. We attribute this result to the nature of the tax base, and exploit additional sources of heterogeneity. Decomposing overall income per capita into its resource and non-resource components, we find that the coefficient on the latter is positive and significant while that on the former is significant but negative.
After briefly reviewing the new institutionalism, this article uses the history of political reform in Africa to test its key tenet: that power, if properly organized, is a productive resource. It does so by exploring the relationship between changes in political institutions and changes in economic performance, both at the macro- and the micro-level. The evidence indicates that political reform (Granger) causes increases in GDP per capita in the African subset of global data. And, at the micro-level, it demonstrates that changes in national political institutions in Africa strongly relate to changes in total factor productivity in agriculture.
Those who study the role of agriculture in the political economy of development focus on government policy choices on the one hand and the impact of price shocks on the other. We argue that the two should be studied together. We nd that civil unrest (Granger) causes government policies, pushing governments in poor and medium income countries to shift relative prices in favor of urban consumers. We also nd that while civil wars are related to food price shocks, when government policy choices are taken into account, the relationship disappears. We thus learn two things: Policies that placate urban consumers may in ict economic costs on governments, but they confer political benets. And when estimating the relationship between price shocks and political stability, equations that omit the policy response of governments are misspecied.
Africa is largely agrarian and the performance of agriculture shapes the performance of its economies. It has long been argued that economic development in Africa is strongly conditioned by politics. Recent changes in Africa’s political systems enables us to test this argument and, by extension, broader claims about the impact of political institutions on economic development. Building on a recent analysis of total factor productivity growth in African agriculture, we find that the introduction of competitive presidential elections in the last decades of the 20th Century appears to have altered political incentives, resulting in policy reforms that have enhanced the performance of farmers.
Africa experienced a wave of democratization over the past 20 years and this increase in democracy, we find, positively and significantly affects income per capita. Our dynamic panel data results suggest that countries only slowly converge to their long-run income values as predicted by current democracy levels, however: African countries may therefore be currently too democratic relative to their income levels. In keeping with this possibility, a significant number of countries experience political ‘back sliding’: elections are won by the use of illicit tactics, term limits on political leaders have been overturned and there have been unconstitutional seizures of power.
The basis for segregation of sister chromosomes in bacteria is not established. We show here that two discrete ~150-kb regions, both located early in the right replichore, exhibit prolonged juxtaposition of sister loci, for 20 and 30 min, respectively, after replication. Flanking regions, meanwhile, separate. Thus, the two identified regions comprise specialized late-splitting intersister connections or snaps. Sister snap loci separate simultaneously in both snap regions, concomitant with a major global nucleoid reorganization that results in emergence of a bilobed nucleoid morphology. Split snap loci move rapidly apart to a separation distance comparable with one-half the length of the nucleoid. Concomitantly, at already split positions, sister loci undergo further separation to a comparable distance. The overall consequence of these and other effects is that thus far replicated sister chromosomes become spatially separated (individualized) into the two nucleoid lobes, while the terminus region (and likely, all unreplicated portions of the chromosome) moves to midcell. These and other findings imply that segregation of Escherichia coli sister chromosomes is not a smooth continuous process but involves at least one and likely, two major global transition(s). The presented patterns further suggest that accumulation of internal intranucleoid forces and constraining of these forces by snaps play central roles in global chromosome dynamics. They are consistent with and supportive of our previous proposals that individualization of sisters in E. coli is driven primarily by internally generated pushing forces and is directly analogous to sister individualization at the prophase to prometaphase transition of the eukaryotic cell cycle.
Don E. Detmer has served as President and Chief Executive Officer of the American Medical Informatics Association (AMIA) for the past five years, helping to set a course for the organization and demonstrating remarkable leadership as AMIA has evolved into a vibrant and influential professional association. On the occasion of Dr. Detmer's retirement, we fondly reflect on his professional life and his many contributions to biomedical informatics and, more generally, to health care in the U.S. and globally.
OBJECTIVE: To use functional MRI (fMRI) to investigate whether hippocampal activation during a memory task can predict cognitive decline in individuals with mild cognitive impairment (MCI). METHODS: 25 older individuals with MCI performed a visual scene encoding task during fMRI scanning, and were followed clinically for at least 4 years after scanning. A hypothesis driven analysis of fMRI data was performed. First, fMRI data were analysed at the group level to identify the regions of the hippocampal formation that were engaged by this memory task. Parameter estimates of each subject's memory related hippocampal activation (% signal change) were extracted and were analysed with a linear regression model to determine whether hippocampal activation predicted the degree or rate of cognitive decline, as measured by change in Clinical Dementia Rating Sum-of-Boxes (CDR-SB). RESULTS: Over 5.9 (1.2) years of follow-up after scanning, subjects varied widely in degree and rate of cognitive decline (change in CDR-SB ranged from 0 to 6, and the rate ranged from 0 to 1 CDR-SB unit/year). Greater hippocampal activation predicted greater degree and rate of subsequent cognitive decline (p<0.05). This finding was present even after controlling for baseline degree of impairment (CDR-SB), age, education and hippocampal volume, as well as gender and apolipoprotein E status. In addition, an exploratory whole brain analysis produced convergent results, demonstrating that the hippocampal formation was the only brain region where activation predicted cognitive decline. CONCLUSIONS: In individuals with MCI, greater memory task related hippocampal activation is predictive of a greater degree and rate of cognitive decline subsequent to scanning. fMRI may provide a physiological imaging biomarker useful for identifying the subgroup of MCI individuals at highest risk of cognitive decline for potential inclusion in disease modifying clinical trials.
OBJECTIVE: Communication failures account for many adverse drug events (ADEs) in adult primary care. Improving patient-physician communication may improve medication safety. Accordingly, the goal of this study was to learn whether electronic medication safety messages directed to patients can improve communication about medications and identify ADEs.
DESIGN: We studied adult patients enrolled in a patient Internet portal at three primary care practices affiliated with a teaching hospital. MedCheck, a medication safety application, sent patients a secure electronic message 10 days after they received a new or changed prescription. MedCheck asked if the patient had filled the prescription or experienced medication-related problems, and then forwarded the patient's response to their primary care physician.
MEASUREMENTS: We selected a stratified random sample of 267 subjects from 1821 patients who received and opened a MedCheck message from April 2001 to June 2002. We reviewed subjects' medical records for three months following their first MedCheck message. We analyzed patient and clinician response rates and times, examined patient-clinician communication about medications, and identified ADEs.
RESULTS: Patients opened 79% of MedCheck messages and responded to 12%; 77% responded within 1 day. Patients often identified problems filling their prescriptions (48%), problems with drug effectiveness (12%), and medication symptoms (10%). Clinicians responded to 68% of patients' messages; 93% answered within 1 week. Clinicians often supplied or requested information (19%), or made multiple recommendations (15%). Patients experienced 21 total ADEs; they reported 17 electronically.
CONCLUSION: Patients and physicians responded promptly to patient-directed electronic medication messages, identifying and addressing medication-related problems including ADEs.
In this chapter, we explore patterns of variation in the content of agricultural policies in Africa. We look at the impact of the government’s need for revenues, the incentives for farmers to lobby, and their capacity to affect electoral outcomes. We also explore the political impact of regional inequality, especially insofar as it is generated by cash crop production. These factors operate in ways that deepen our appreciation of the impact of politics on the making of agricultural policies.
The period from 1960 to 2000 was one of remarkable growth and
transformation in the world economy. Why did most of Sub-Saharan Africa
fail to develop over this period? Why did a few small African economies
succeed spectacularly? The Political Economy of Economic Growth in
Africa, 1960–2000 is by far the most ambitious and comprehensive
assessment of Africa's post-independence economic performance to date.
Volume 2 supports and extends the analysis of African economic growth
presented in the first volume by providing twenty-six case studies of
individual African economies. The book is broken into three parts based
on the three main types of economy found in Sub-Saharan Africa:
landlocked, coastal and resource-rich. Eighteen of the case studies are
contained in the book and a further eight are included on an
accompanying CD-Rom. This is an invaluable resource for researchers and
policy-makers concerned with the economic development of Africa.
the later decades of the 20th century, Africa plunged into political chaos. States failed, governments became predators, and citizens took up arms. In When Things Fell Apart, Robert H. Bates advances an explanation of state failure in Africa. In so doing, he not only plumbs the depths of the continent's late-century tragedy, but also the logic of political order and the foundations of the state. This book covers a wide range of territory by drawing on materials from Rwanda, Sudan, Liberia, and Congo. Written to be accessible to the general reader, it is nonetheless a must-read for scholars and policy makers concerned with political conflict and state failure.
In the later decades of the twentieth century, Africa plunged into
political chaos. States failed, governments became predators, and
citizens took up arms. In When Things Fell Apart, Robert H. Bates
advances an exploration of state failure in Africa. In so doing, he not
only plumbs the depths of the continent's late-century tragedy, but
also the logic of political order and the foundations of the state.
This book covers a wide range of territory by drawing on materials from
Rwanda, Sudan, Liberia, and Congo. A must-read for scholars and policy
makers concerned with political conflict and state failure.