Many attempts have been made to quantify Africa's malaria burden but none has addressed how urbanization will affect disease transmission and outcome, and therefore mortality and morbidity estimates. In 2003, 39% of Africa's 850 million people lived in urban settings; by 2030, 54% of Africans are expected to do so. We present the results of a series of entomological, parasitological and behavioural meta-analyses of studies that have investigated the effect of urbanization on malaria in Africa. We describe the effect of urbanization on both the impact of malaria transmission and the concomitant improvements in access to preventative and curative measures. Using these data, we have recalculated estimates of populations at risk of malaria and the resulting mortality. We find there were 1,068,505 malaria deaths in Africa in 2000 -a modest 6.7% reduction over previous iterations. The public-health implications of these findings and revised estimates are discussed.We have become accustomed to the rapid growth of the human population and are no longer surprised to read that there was a fourfold increase in the size of the human population (from 1.65 billion to 6.1 billion) between 1900 and 2000. Eighty percent of this increase occurred after 1950 (REF. 1; FIG. 1a). It is perhaps less well known that at the start of the twenty-first century 2.9 billion people were living in urban areas, and that almost all of the 2.2 billion people estimated to be born between 2000 and 2030 will become urban residents. By 2008, it is predicted that the number of urban dwellers will exceed the rural population for the first time 2 .Correspondence to S.I.H. simon.hay@zoo.ox.ac.uk. Competing interests statement: The authors declare no competing financial interests. These population dynamics have significant public-health implications [3][4][5] . A shift in human populations from rural to urban environments will change global patterns of disease and mortality [6][7][8] . In rural areas of low-income countries morbidity and mortality are mainly due to infectious diseases, whereas in urban areas morbidity and mortality are generally caused by non-communicable diseases (for example, chronic, degenerative and cardiovascular diseases); however, the evolving HIV pandemic has begun to influence these patterns due to its higher prevalence in urban areas 9 . In Africa, the world's most rapidly urbanizing continent, this transition will be particularly acute (FIG. 1b). In 2003, 39% of 850 million Africans were living in urban areas, and this is projected to increase to 54% by 2030 (REF. 10). Malaria and global public healthNatural transmission of malaria infection occurs by exposure to the bites of infective female anopheles mosquitoes 11 . The alternation between the human host and the mosquito vector represents the biological cycle of malaria transmission 12 . Plasmodium falciparum is the most common and clinically serious of the four malaria parasite species that infect humans and is found throughout the tropics and subtropics 13 . Climate...

A simple, efficient algorithm is presented for sub-pixel target mapping from remotely-sensed images. Following an initial random allocation of "soft" pixel proportions to "hard" subpixel binary classes, the algorithm works in a series of iterations, each of which contains three stages. For each pixel, for all sub-pixel locations, a distance-weighted function of neighboring sub-pixels is computed. Then, for each pixel, the sub-pixel representing the target class with the minimum value of the function, and the sub-pixel representing the background with the maximum value of the function are found. Third, these two sub-pixels are swapped if the swap results in an increase in spatial correlation between sub-pixels. The new algorithm predicted accurately when applied to simple simulated and real images. It represents an accessible tool that can be coded and applied readily by remote sensing investigators.

BackgroundAppropriate facility-based care at birth is a key determinant of safe motherhood but geographical access remains poor in many high burden regions. Despite its importance, geographical access is rarely audited systematically, preventing integration in national-level maternal health system assessment and planning. In this study, we develop a uniquely detailed set of spatially-linked data and a calibrated geospatial model to undertake a national-scale audit of geographical access to maternity care at birth in Ghana, a high-burden country typical of many in sub-Saharan Africa.MethodsWe assembled detailed spatial data on the population, health facilities, and landscape features influencing journeys. These were used in a geospatial model to estimate journey-time for all women of childbearing age (WoCBA) to their nearest health facility offering differing levels of care at birth, taking into account different transport types and availability. We calibrated the model using data on actual journeys made by women seeking care.ResultsWe found that a third of women (34%) in Ghana live beyond the clinically significant two-hour threshold from facilities likely to offer emergency obstetric and neonatal care (EmONC) classed at the ‘partial’ standard or better. Nearly half (45%) live that distance or further from ‘comprehensive’ EmONC facilities, offering life-saving blood transfusion and surgery. In the most remote regions these figures rose to 63% and 81%, respectively. Poor levels of access were found in many regions that meet international targets based on facilities-per-capita ratios.ConclusionsDetailed data assembly combined with geospatial modelling can provide nation-wide audits of geographical access to care at birth to support systemic maternal health planning, human resource deployment, and strategic targeting. Current international benchmarks of maternal health care provision are inadequate for these purposes because they fail to take account of the location and accessibility of services relative to the women they serve.

11Logistic regression studies which assess landslide susceptibility are widely available in the literature. 12However, a global review of these studies to synthesise and compare the results does not exist. There 13 are currently no guidelines for selection of covariates to be used in logistic regression analysis and as 14 such, the covariates selected vary widely between studies. An inventory of significant covariates 15 associated with landsliding produced from the full set of such studies globally would be a useful aid to 16 the selection of covariates in future logistic regression studies. Thus, studies using logistic regression 17 for landslide susceptibility estimation published in the literature were collated and a database created 18 of the significant factors affecting the generation of landslides. The database records the paper the 19 data were taken from, the year of publication, the approximate longitude and latitude of the study 20 area, the trigger method (where appropriate), and the most dominant type of landslides occurring in 21 the study area. The significant and non-significant (at the 95% confidence level) covariates were 22 recorded, as well as their coefficient, statistical significance, and unit of measurement. The most 23 common statistically significant covariate used in landslide logistic regression was slope, followed by 24 aspect. The significant covariates related to landsliding varied for earthquake-induced landslides 25 compared to rainfall-induced landslides, and between landslide type. More importantly, the full range 26 of covariates used was identified along with their frequencies of inclusion. The analysis showed that 27 2 there needs to be more clarity and consistency in the methodology for selecting covariates for logistic 28 regression analysis and in the metrics included when presenting the results. Several recommendations 29 for future studies were given. 30 31

No abstract

The archives of imagery and modeled data products derived from remote sensing programs with high temporal resolution provide powerful resources for characterizing inter- and intra-annual environmental dynamics. The impressive depth of available time-series from such missions (e.g., MODIS and AVHRR) affords new opportunities for improving data usability by leveraging spatial and temporal information inherent to longitudinal geospatial datasets. In this research we develop an approach for filling gaps in imagery time-series that result primarily from cloud cover, which is particularly problematic in forested equatorial regions. Our approach consists of two, complementary gap-filling algorithms and a variety of run-time options that allow users to balance competing demands of model accuracy and processing time. We applied the gap-filling methodology to MODIS Enhanced Vegetation Index (EVI) and daytime and nighttime Land Surface Temperature (LST) datasets for the African continent for 2000–2012, with a 1 km spatial resolution, and an 8-day temporal resolution. We validated the method by introducing and filling artificial gaps, and then comparing the original data with model predictions. Our approach achieved R2 values above 0.87 even for pixels within 500 km wide introduced gaps. Furthermore, the structure of our approach allows estimation of the error associated with each gap-filled pixel based on the distance to the non-gap pixels used to model its fill value, thus providing a mechanism for including uncertainty associated with the gap-filling process in downstream applications of the resulting datasets.

No abstract

No abstract