FAO’s AVHRR-based Agricultural Stress Index System (ASIS) for global drought monitoring

Agricultural production is highly dependent on climate variability in many parts of the world. In particular, drought may severely reduce crop yields, potentially affecting food availability at local, regional, and global scales. The Food and Agriculture Organization of the United Nations (FAO) operates the Global Early Warning System (GIEWS), which monitors global food supply and demand. One of the key challenges is to obtain synoptic information on a recurrent and timely basis about drought-affected agricultural zones. This is needed to quickly identify areas requiring immediate attention. The Agricultural Stress Index System (ASIS), based on imagery from the Advanced Very High Resolution Radiometer (AVHRR) sensors on board the National Oceanic and Atmospheric Administration (NOAA) and Meteorological Operational Satellite (METOP) satellites, was specifically developed to meet this need. The system is based on a methodology developed by Rojas, Vrieling, and Rembold over the African continent. This approach has been modified and adapted to the global scale to produce an agricultural stress index (ASI) representing, per administrative unit, the percentage of cropland (or pasture) areas affected by drought over the growing season. The vegetation health index (VHI), based on normalized difference vegetation index (NDVI) and temperature anomalies, is used as a drought indicator. A fused time series of AVHRR data from METOP and NOAA was used to produce a consistent time series of VHI at 1 km resolution. Global phenology maps, indicating the number of growing seasons and their start and end dates, were derived from a multi-annual image set of SPOT-Vegetation (1999–2011). The VHI time series and phenology maps were then combined to produce the ASI for the years 1984 to the present. This allowed evaluation of the suitability of the ASIS to identify drought using historical reports and ancillary data. As a result of this analysis, ASIS was positively evaluated to support the FAO early warning system.     

Analysis of the Functional Block Involved in the Design of Radial Basis Function Networks

The main architectures, learning abilities and applications of radial basis function (RBF) neural networks are well documented. However, to the best of our knowledge, no in-depth analyses have been carried out into the influence on the behaviour of the neural network arising from the use of different alternatives for the design of an RBF (different non-linear functions, distances, number of neurons, structures, etc.). Thus, as a complement to the existing intuitive knowledge, it is necessary to have a more precise understanding of the significance of the different alternatives. In the present contribution, the relevance and relative importance of the parameters involved in such a design are investigated by using a statistical tool, the ANalysis Of the VAriance (ANOVA). In order to obtain results that are widely applicable, various problems of classification, functional approximation and time series estimation are analyzed. Conclusions are drawn regarding the whole set.     

Infant feeding practices in St. Vincent and factors which affect them

A survey was conducted in the summer of 1975 in 2 towns in St. Vincent--Layou and Georgetown--in the effort to obtain information regarding infant feeding practices and some of the factors which may influence them. Mothers of children from 1-2 years of age were interviewed in their homes. Complete data sets were obtained on 192 of the 216 eligible children in the 2 towns. For most children the period of exclusive breastfeeding (no other milk product given) was very short. About 1/2 of the children had received milk by 2 weeks of age, and 75% by 1 month. This was followed by a much longer period of "mixed" feeding--both breast and bottle--until breastfeeding was stopped at a median age of 6.8 months. Many types of milk were used for infant feeding. For 73% of the infants, infant formula was the 1st type of milk given. This was commonly replaced by a "heavier" full cream powdered milk at a few months of age. Prelacteal feeds were very common, predominantly glucose water. "Tonics," often consisting of vitamin preparations, were another common supplement during the early months of life. Among solid foods, arrowroot, "custard," and commercial infant cereals were the first to be introduced. Relatively inexpensive locally bagged staple foods and milk powders were available in both towns, but most mothers relied heavily on packaged brand name products for infant feeding even though the cost was 2-10 times higher. It was not possible to pinpoint the exact causes for the high levels of bottle feeding, nor for the possible recent decline in breastfeeding, but several important factors were identified. Part of the problem appeared to be due to poor health and nutritional status of the mothers. In addition, in several cases the mothers reported that they had wanted to continue breastfeeding but had received no support from health professionals, and in a few instances had been ordered to stop for seemingly trivial medical reasons.     

Inhibition of HeLa cell messenger RNA translation by 7-methylguanosine 5'-monophosphate

Translation of HeLa cell RNA containing poly(A) in a wheat germ cell-free system is markedly but incompletely inhibited by 7-methylguanosine 5'-monophosphate (m7G5'p). We have analyzed the translation products synthesized in the presence of different concentrations of m7G5'p and find that translation of all mRNAs is equally inhibited. To demonstrate the specificity of the inhibitor for RNAs with 5'-terminal m7G5' ppp... we show that specific translation products of satellite tobacco necrosis virus RNA, which does not have this 5' terminus, are synthesized in the presence of m7G5' p. Protein synthesis programmed by endogenous mRNA in a HeLa cell-free system is inhibited after a 10-min lag by m7G5' p. Other guanosine nucleotides without the 7-methyl group or with the phosphate in a different position are not inhibitor. We show that translation of all mRNAs is inhibited to a similar extent by m7G5'p in the HeLa cell-free system, by synthesizing 35S-labeled proteins in the presence of different inhibitory concentrations of this nucleotide and analyzing the translation products by electrophoresis and autoradiography. Translation of encephalomyocarditis virus RNA added to the HeLa cell-free system is not inhibited by m7"g5p; this viral RNA does not have this nucleotide at the 5' terminus. This indicates that m7G5'p specifically inhibits translation of mRNAs with the 5' terminus m7G5'ppp... and suggests that initiation of translation of picornavirus RNA may proceed via a mechanism different from that of cellular mRNAs.     

Research Validation: Challenges and Opportunities in the Construction Domain

Validation of the research methodology and its results is a fundamental element of the process of scholarly endeavor. Approaches used for construction engineering and management research have included experiments, surveys and observational studies, modeling and simulation, theory building, case studies, and various subtypes thereof. Some studies use more than one approach. A particular contribution of this paper is that it reviews different types of validation using examples of studies, analyzes the specific challenges that were found to be significant, and presents how they were successfully overcome in each case. Another contribution is that it describes new opportunities for research validation that are emerging at the horizon as well as ongoing collaborative efforts to enhance the access of construction researchers to validation tools. This paper increases the awareness of the paramount role that validation techniques play in scholarly work by providing readers with recommendations to properly validate their own research efforts.     

In vitro displacement by rat serum of adsorbed radiolabeled poloxamer and poloxamine copolymers from model and biodegradable nanospheres

Poloxamer 407 and poloxamine 908 have been used by many research groups to modify the surface of both model latex and biodegradable nanospheres, thereby producing nanospheres that have shown reduced protein adsorption in vitro and extended circulation times in vivo. A potential limitation of such systems is the desorption of the copolymer coating layer. We describe a two-stage process to radiolabel poloxamer 407 and poloxamine 908 that has facilitated an investigation into this potential desorption, in vitro. The first stage of the labeling procedure involved the substitution of the terminal hydroxyl groups in each poly(ethylene oxide) (PEO) chain of poloxamer 407 and poloxamine 908 with an amino group. The aminated copolymers were then radiolabeled with 125Iodine Bolton-Hunter reagent. The efficiency of labeling was calculated to be approximately 20% for the tetramine poloxamine 908 and approximately 33% for the diamine poloxamer 407. Remaining free amino groups were then either acetylated, using acetic anhydride, or left in the free amino form. Covalent linkage of the radiolabel to the copolymer was confirmed by nuclear magnetic resonance (NMR) and infrared (IR) spectroscopy. The stability of the link between radiolabel and copolymer to hydrolysis was also confirmed; <4% loss of radiolabel occurred from poloxamine 908 after incubation in phosphate-buffered saline (PBS) at 37 degrees C for 8 days. The radiolabeled copolymers (with the free amino groups acetylated) were then used in experiments that have given the first direct evidence that adsorbed copolymers can be displaced by serum proteins in significant amounts from the surface of model and biodegradable nanospheres. The displacement was highly dependent on copolymer-nanosphere compatibility, with up to 78% of 125I tetramine poloxamine 908 being displaced from poly(lactide-co-glycolide) (PLGA) nanospheres in 24 h, compared with 20% displacement of 125I tetramine poloxamine 908 in 24 h from polystyrene nanospheres. These results have direct implication for the future design of drug delivery systems based on coated nanospheres.     

A regulatory role for recombinase activating genes, RAG-1 and RAG-2, in T cell development

Effects of etoposide (VP-16) and cytosine arabinoside (Ara-C) on the cell cycle of HL-60 and THP-1 cells were studied by flow cytometry using the bromodeoxyuridine (BrdU)/DNA assay technique to investigate the efficacy of VP-16 for monocytic leukemia cells. VP-16 inhibited the proliferation of THP-1 cells more strongly than that of HL-60 cells at any concentrations used at 24 and 48 hr. VP-16 arrested HL-60 and THP-1 cells in the G2/M phase and reduced them in the G0/G1 and early S phase at higher concentrations. There was no significant difference in the percentage of G2/M phase cells at the same concentration between both cells. However, reduction in the G0/G1 and early S phase cells was more marked in THP-1 than HL-60 cells significantly. On the other hand, Ara-C perturbed the cell cycle of HL-60 cells more than that of THP-1 cells at 24 and 48 hr. These results suggest that the effects of VP-16 on the cell cycle may be more intense in THP-1 than HL-60 cells, and support the efficacy of VP-16 for treating monocytic leukemia in vivo.