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Maize, a staple food in most African countries, is prone to contamination by aflatoxins, toxic secondary metabolites mainly produced by Aspergillus flavus and A. parasiticus. Aflatoxins are known to cause liver cancer, and chronic exposure has been linked to other adverse health outcomes including growth faltering in children. To mitigate exposure in maize-dependent populations, there is need to identify the factors associated with aflatoxin contamination. This is difficult, however, because of high sampling cost and lack of affordable and accurate analytical methods. Publicly available, remotely-sensed data on vegetation, precipitation, and soil properties could be useful in predicting locations at risk for aflatoxin contamination in maize. This study investigates the utility of publicly available remotely-sensed data on rainfall, vegetation cover (indicated by normalized difference vegetation index or NDVI), and soil characteristics as potential predictors of aflatoxin contamination in Kenyan maize. Aflatoxin was analyzed in maize samples (n=2466) that were collected in 2009 and 2010 at 243 local hammer mills in eastern and western Kenya. Overall, 60% of maize samples had detectable aflatoxin. Global positioning system coordinates of each mill location were linked to remotely-sensed, spatially explicit indicators of average monthly NDVI, total monthly rainfall, and soil properties. Higher rainfall and vegetation cover during the maize pre-flowering period were significantly associated with higher prevalence of aflatoxin contamination. Conversely, higher rainfall and vegetation cover during the maize flowering and post-flowering periods (not including harvest) were associated with lower prevalence of aflatoxin contamination. Water stress throughout the growing season may cause increased plant susceptibility to fungal colonization and aflatoxin accumulation. Soil organic carbon content, pH, total exchangeable bases, salinity, texture, and soil type were significantly associated with aflatoxin. In conclusion, this study shows that remotely-sensed data can be regressed on available aflatoxin data highlighting important potential predictors that could reduce the cost of data collection and the cost of aflatoxin risk forecasting models. Key words: Aflatoxin, GIS, NDVI, soil characteristics, rainfall, mycotoxins, East Africa, Kenya, INTRODUCTION It is estimated that approximately 4.5 billion people, predominantly those living in developing countries, are at risk of being exposed to dietary aflatoxins, with many chronically exposed at high [...]

This paper provides a quantitative measurement of the benefit that a Unified Power Flow Controller (UPFC) can provide to increase firm power transfer between two large power systems. Included is a complete model for a UPFC control system that contains bus voltage control by the shunt inverter, real power transfer between the shunt and series inverters, and real and reactive power control for the transmission line into which the series inverter is inserted. A significant part of the model is representation of dynamic limits that coordinate injected current limits for the shunt inverter, power transfer limits between inverters, voltage injection limits for the series inverter, current limits for the series inverter, and line voltage limits for the transmission line. This paper contains a simple system simulation to demonstrate the coordinated dynamic control and illustrate issues that system planning engineers must consider in defining applications for a UPFC. KEYWORDS: Power Flow Control, Voltage Control, Static Synchronous Compensator, Unified Power Flow Controller, Voltage Sourced Inverters

Examination of the genetic diversity of Xanthomonas oryzae pv. oryzae, collected from various rice-growing countries in Asia, by restriction fragment length polymorphism and virulence analyses reveals that the collection forms five types of clusters. Genetic distances between clusters ranged from 0.48 to 0.64 and distances within the five clusters range from 0.16 to 0.51. Majority of the strains from South Asia exhibit virulence toward cultivars with the bacterial blight resistance gene xa-5, while strains from other countries exhibit avirulence toward xa-5.

This paper presents the characteristics of two gate turn-off (GTO) thyristor voltage-sourced inverter-based series power flow control devices, namely the Series Power Flow Controller (SPFC) and the Unified Power Flow Controller (UPFC). These devices represent series extensions of the STATCON, an inverter-based shunt device developed under a tailored collaboration by EPRI, TVA and the Westinghouse Science and Technology Center, which will soon be placed in service on the TVA 161kV transmission system for transmission voltage control. Operation of the SPFC and UPFC is illustrated through the use of easily-constructed circle diagrams on the P-Q plane. The circle diagrams provide the transmission planning engineer with a simple means to assess the performance of these devices on the transmission system. A concluding example illustrates that the UPFC provides a level of power flow control which is unattainable with more conventional devices. KEYWORDS: Power Flow Control, Series Power Flow Controller, Unified Power Flow Controller, Circle Diagrams, Gate Turn-off Thyristor

This paper introduces a new transmission control device, the Line Compensating Phase Angle Regulator (LCPAR), which permits simultaneous control of transmission voltage phase angle, apparent line reactance, and apparent line resistance. The device permits full utilization of the transmission line it serves with minimum loss. The paper describes a load flow model and provides an explicit comparison of the performance of the LCPAR with a more conventional phase angle regulating transformer, either with electromechanical switching or solid state switching. By permitting full utilization (up to the thermal limit) of existing or new transmission lines, the device may defer or eliminate the need for new transmission.

The vertebrate immune system is costly to use and develop, but the extent to which the induction of immune activity affects fitness (a proxy for survival costs) remains unspecified. Three days after birth, we induced immune activity in neonatal male and female Siberian hamsters (P/~x8 sungorus) with lipopolysaccharide (LPS), a fever-inducing component of gram-negative bacteria, and compared i) the progression of puberty, ii) the strength of immune defenses, and iii) reproductive behavior and output of animals (once they had reached adulthood) to saline-challenged control hamsters. Both groups consisted of siblings randomly chosen from litters. After weaning (18 days old), all animals were housed singly, fed ad libitum, and kept on a 16:8 hour light:dark cycle until maturation was complete. LPS-challenges reduced the body temperatures of neonates (both males and females) and slowed gonad growth of juveniles (males only) compared to saline controls. Peripubertal body mass however was not different between groups. Once animals mature, immune defenses (delayed-type hypersensitivity (DTH), wound healing, and antibody production), as well as reproductive behavior and reproductive organ mass of males and reproductive output of females will be determined. If short-term costs of immune activity have long-term consequences for fitness, then these measures will be reduced in LPS-challenged hamsters relative to controls. Further, we will compare androgen and estrogen concentrations between groups throughout maturation to determine whether the costs of immune activity are mediated by steroid hormones. Finally, we will determine whether the costs of immune activity span generations by comparing the reproductive output and strength of immune defenses of offspring (post-weaning) from LPS and saline-challenged parents.

The population genetics of Magnaporthe grisea, the rice blast pathogen, were analyzed in a center of rice diversity (the Uttar Pradesh hills of the Indian Himalayas) using multilocus and single-, or low-copy, DNA markers. based on DNA fingerprinting with the multilocus probe MGR586 and single-locus probes, 157 haplotypes clustered into 56 lineages (at [greater than or equal to]70% MGR586 band similarity, each with unique single-locus profiles) and high diversity indices were detected among 458 isolates collected from 29 sites during 1992-1995. Most valleys sampled had distinct populations (73% of the lineages were site specific) with some containing one or a few lineages, confirming the importance of clonal propagation, and others were very diverse. Widely distributed lineages suggested that migration occurs across the region and into the Indo-Gangetic plains. Repeated sampling at one site, Matli, (170 isolates, 1992-1995) yielded 19 lineages and diversity significantly greater than that reported from similar samples from Colombia and the Philippines. Analysis of allelic associations using pairwise comparisons and multilocus variance analysis failed to reject the hypothesis of gametic phase equilibrium. The Matli population shifted from highly diverse in 1992 to almost complete dominance by one lineage in 1995. Such population dynamics are consistent with recombination followed by differential survival of clonal descendants of recombinant progeny. At another site, Ranichauri, population (n = 84) composition changed from 2 to 11 lineages over 2 yr and yielded additional evidence for equilibrium. Sexually fertile and hermaphrodite isolates of both mating types were recovered from rice in both Matli and Ranichauri. We demonstrate that Himalayan M. grisea populations are diverse and dynamic and conclude that the structure of some populations may be affected to some extent by sexual recombination.