Making information and communication technologies work for food security in Africa

"Africa faces a difficult challenge in meeting the main target of the first Millennium Development Goal — to halve the number of people suffering from malnutrition and hunger by 2015. Bridging the digital divide through the development and use of information and communication technologies (ICTs)—such as fixed-line and mobile phones and Internet services—will not directly solve this challenge, but it can make a significant contribution." from Text

Semiparametric Evidence on the Nature of Price Transmission in Tanzanian Maize Markets

Maize is a major staple food in Sub-Saharan Africa. Monthly maize prices in Tanzania are analyzed since the country is an important maize producer and exporter in East Africa. We analyze price transmission between the five most important urban regions of Tanzania between 2000 and 2008 which correspond to major maize production or consumption areas. We propose a novel method for the analysis. The semiparametric vector error-correction model allows the partial impact of the past deviations from price equilibria on current price changes to be potentially nonlinear. The nonparametric estimates of these partial influences suggest that they can be adequately modeled by linear functions.cointegration, maize, nonlinear time series model, price transmission, semiparametric model, Tanzania., Crop Production/Industries, Marketing, C32, Q11, Q13,

Mapping the results of local statistics

The application of geographically weighted regression (GWR) – a local spatial statistical technique used to test for spatial nonstationarity – has grown rapidly in the social, health and demographic sciences. GWR is a useful exploratory analytical tool that generates a set of location-specific parameter estimates which can be mapped and analysed to provide information on spatial nonstationarity in relationships between predictors and the outcome variable. A major challenge to GWR users, however, is how best to map these parameter estimates. This paper introduces a simple mapping technique that combines local parameter estimates and local t-values on one map. The resultant map can facilitate the exploration and interpretation of nonstationarity.geographically weighted regression, local statistics, mapping, nonstationarity

Residential Proximity to Major Roadways at Birth, DNA Methylation at Birth and Midchildhood, and Childhood Cognitive Test Scores: Project Viva(Massachusetts, USA).

BackgroundEpigenetic variability is hypothesized as a regulatory pathway through which prenatal exposures may influence child development and health.ObjectiveWe sought to examine the associations of residential proximity to roadways at birth and epigenome-wide DNA methylation. We also assessed associations of differential methylation with child cognitive outcomes.MethodsWe estimated residential proximity to roadways at birth using a geographic information system (GIS) and cord blood methylation using Illumina's HumanMethylation450-array in 482 mother-child pairs in Project Viva. We identified individual CpGs associated with residential-proximity-to-roadways at birth using robust linear regression [[Formula: see text]]. We also estimated association between proximity-to-roadways at birth and methylation of the same sites in blood samples collected at age 7-11 y ([Formula: see text]). We ran the same analyses in the Generation R Study for replication ([Formula: see text]). In Project Viva, we investigated associations of differential methylation at birth with midchildhood cognition using linear regression.ResultsLiving closer to major roadways at birth was associated with higher cord blood (and-more weakly-midchildhood blood) methylation of four sites in LAMB2. For each halving of residential-proximity-to-major-roadways, we observed a 0.82% increase in DNA methylation at cg05654765 [95% confidence interval (CI): (0.54%, 1.10%)], 0.88% at cg14099457 [95% CI: (0.56%, 1.19%)], 0.19% at cg03732535 [95% CI: (0.11%, 0.28)], and 1.08% at cg02954987 [95% CI: (0.65%, 1.51%)]. Higher cord blood methylation of these sites was associated with lower midchildhood nonverbal cognitive scores. Our results did not replicate in the Generation R Study.ConclusionsOur discovery results must be interpreted with caution, given that they were not replicated in a separate cohort. However, living close to major roadways at birth was associated with cord blood methylation of sites in LAMB2-a gene known to be linked to axonal development-in our U.S. cohort. Higher methylation of these sites associated with lower nonverbal cognitive scores at age 7-11 y in the same children. https://doi.org/10.1289/EHP2034

Like Deck Chairs on the Titantic: Why Spectrum Reallocation Won\u27t Avert the Coming Data Crunch But Technology Might Keep the Wireless Industry Afloat

Skyrocketing mobile data demands caused by increasing adoption of smartphones, tablet computers, and broadband-equipped laptops will soon swamp the capacity of our nation\u27s wireless networks, afact that promises to stagnate a $1 trillion slice of the nation\u27s economy. Among scholars and policymakers studying this looming spectrum crisis, consensus is developing that regulators must swiftly reclaim spectrum licensed to other industries and reallocate those rights to wireless providers. In this interdisciplinaryp iece, we explain in succinct terms why this consensus is wrong. With data demands increasing at an exponential rate, spectrum reallocation plans that promise only linear growth are destined to fail. What regulators should focus on, instead, are policies that encourage the sluggish incumbents presently dominating the wireless industry to roll out new networking technologies (like tiered network architectures, cognitive radio, and multicell MIMO) that together may allow exponential increases in spectral efficiency