Assembly of cytochrome c oxidase within the mitochondrion

Cytochrome c oxidase (CcO) is an oligomeric complex localized within the mitochondrial inner membrane. Assembly of the active oxidase complex requires the coordinate assembly of subunits synthesized in both the cytoplasm and the mitochondrion. In addition, assembly is dependent on the insertion of five types of cofactors, including two hemes, three copper ions, and one Zn, Mg, and Na ion. A series of accessory proteins are critical for synthesis of the heme A cofactor and insertion of the copper ions. This Account will focus on the steps in the coordinate assembly of CcO subunits, the formation of heme A, and the delivery and insertion of copper ions.     

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A method for calibrated maximum likelihood classification of forest types

A modification to the maximum likelihood algorithm was developed for classification of forest types in Sweden's part of the CORINE land cover mapping project. The new method, called the “calibrated maximum likelihood classification” involves an automated and iterative adjustment of prior weights until class frequency in the output corresponds to class frequency as calculated from objective (field-inventoried) estimates. This modification compensates for the maximum likelihood algorithm's tendency to over-represent dominant classes and under-represent less frequent ones. National forest inventory plot data measured from a five-year period are used to estimate relative frequency of class occurrence and to derive spectral signatures for each forest class. The classification method was implemented operationally within an automated production system which allowed rapid production of a country-wide forest type map from Landsat TM/ETM+ satellite data. The production system automated the retrieval and updating of forest inventory plots, a plot-to-image matching routine, illumination and haze correction of satellite imagery, and classification into forest classes using the calibrated maximum likelihood classification. This paper describes the details of the method and demonstrates the result of using an iterative adjustment of prior weights versus unadjusted prior weights. It shows that the calibrated maximum likelihood algorithm adjusts for the overclassification of classes that are well represented in the training data as well as for other classes, resulting in an output where class proportions are close to those as expected based on forest inventory data.     

Agricultural burning in the Southeastern United States detected by MODIS

The southeastern United States, including the states of Alabama, Arkansas, Florida, Georgia, Kentucky, Louisiana, Mississippi, North Carolina, South Carolina, Tennessee, and Virginia, had a high occurrence of fire activity as detected by the 1 km Moderate Resolution Imaging Spectroradiometer (MODIS) TERRA Active Fire Product (MOD 14). The analysis of the satellite data from 2001 to 2004 showed that agricultural burning in the southeastern United States accounted for an average of 16% of annual fire activity. The southeastern region contributed an average of 33% of all agricultural burning detected in the contiguous United States. Crop residues that burned in the southeast included rice, winter wheat, sugarcane, soybean and cotton. Much of the agricultural burning occurred in June and from October to January and was related to the harvest of winter wheat and rice in the spring and the harvest of sugarcane, soybean and cotton in the fall and winter. The results showed that cropland burning was spatially dependent on crop type and temporally dependent on management practices (planting/harvesting). Arkansas, Florida, and Louisiana contributed more than 75% of all agricultural burning in the southeast. A 250 m MODIS land cover map cover for 2004 was developed for these three states using a decision tree classification and validation from a field campaign in the fall of 2004. Compared to the standard MODIS 1 km Land Cover Dataset (MOD 12) product ([Friedl, M. A., McIver, D. K., Hodges, J. C. F., Zhang, X. Y., Muchoney, D., Strahler, A. H., Woodcock, C. E., Gopal, S., Schneider, A., Cooper, A., Baccini, A., Gao, F., Schaaf, C. (2002), Global land cover mapping from MODIS: algorithms and early results. Remote Sensing of the Environment, 83, 287-302.]), the 250 m classified images contained on average 50% more cropland area and improved the estimation of cropland area based on validation from ground control sites of croplands. Results from the decision tree classification for each state revealed that in 2004 agricultural burning contributed 73%, 54%, and 33% of total fires for Arkansas, Florida, and Louisiana, respectively.     

Effect of wavelength selection on characterization of fire size and temperature

Over the past two decades, Dozier's 1981 retrieval method has been used with observations from various moderate-resolution (～ 1 km) spaceborne sensors to estimate the instantaneous sub-pixel area and temperature of wildfires. The method requires simultaneous observations at two different wavelengths. Traditionally these wavelengths have resided in the middle- and long-wave infrared regions, for example the 4 and 11 @m channels of the NOAA Advanced Very High Resolution Radiometer (AVHRR). Development of recent and upcoming sensors, including the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Visible/Infrared Imager/Radiometer Suite (VIIRS), have spawned interest in using other wavelength combinations, particularly in the short-wave infrared, for sub-pixel active fire characterization. We demonstrate that for realistic wildfires, which are composed of both flaming and smouldering components, the location of these two wavelengths can cause large differences in the fire temperatures and areas that are retrieved using Dozier's method. In the worst case considered, differences of 250 K in temperature and 80% in area were observed.     

A new land cover map of central Africa derived from multi-resolution,multi-temporal AVHRR data

We describe a new map of the central Africa region that was derived from National Oceanic and Atmospheric Administration Advanced Very High Resolution Radiometer (NOAA AVHRR) observations using a fusion of Local Area Coverage (LAC, 1 km), Global Area Coverage (GAC, 8 km), and ancillary information. The land cover map, produced for the Central Africa Regional Program for the Environment (CARPE), offers a synoptic view of the extent of central African dense humid forests, at relatively fine spatial resolution. Land cover types include dense humid forest, disturbed or degraded forest and various savanna classes. Ancillary information includes political and park boundaries, settlements, rivers and roads. Map validation was performed using a combination of field visits and finer resolution imagery (Landsat Multi-Spectral Scanner (MSS)). Forest cover type mapping errors were at most 20 per cent. The resulting map is useful for addressing a number of resource management issues, a few of which are examined.     

Interaction of bile salts with gastrointestinal mucins

The properties of three mucins were examined to identify the structural features responsible for their functional differences. Bovine submaxillary mucin (BSM), porcine gastric mucin (PGM), and rat intestinal mucin (RIM) were each characterized, and high carbohydrate contents were found for RIM and PGM. The amino acid compositions were typical of mucin glycoproteins, with over half comprising small, neutral amino acids. Thereafter, each mucin was equilibrated with three different series of concentrations of the bile salts sodium taurocholate, sodium taurodeoxycholate, and sodium taurochenodeoxycholate. Following multiple centrifugations, the supernatant and mucin pellet concentrations of the bile salts were measured. The bile salt pellet concentration was plotted as a function of supernatant concentration, and from the slopes, the excluded volumes were calculated as 25, 29–44, and 28–55 mL/g for BSM, RIM, and PGM, respectively. The intercepts were 8–10, 2–3, and 1–3 mM for BSM, RIM, and PGM, respectively, which represents an estimate of the bound concentration of bile salt. Differences among the bile salts were observed in the excluded volume and amount bound, but no trends were evident. The bile salts may interact as aggregates with the hydrophobic areas and carbohydrate side chains of the mucins, providing favorable sites for association. The binding at low concentrations with exclusion at high concentrations is significant for modulating the absorption of lipid aggregates from the intestine. Finally, the differences among the mucins reflect the unique structure-function relationship of these gastrointestinal mucins.     

Modeling improvements in booster seat use: a discrete choice conjoint experiment

Automobile crashes are the leading cause of death in children aged 1–14 years. Many children, however, are not properly restrained in safety seats that reduce serious injury and death. This study used a discrete choice conjoint experiment to study factors influencing the decision to use booster seats. Parents of 1714 children aged 4–9 years from nine Canadian provinces completed choice tasks presenting experimentally varied combinations of 15 4-level booster seat promotion attributes. Latent class analysis yielded three segments of parents. The choices of the Benefit Sensitive segment (50%) were most sensitive to the injury prevention benefits of booster seats. The choices of parents in the Context Sensitive segment (33.5%) were more likely to be influenced by installation complexity, oppositional behavior, and the prospect that their child may be teased for riding in booster seats. Parents in the High Risk segment (16.5%) were younger, less educated, and less knowledgeable about vehicle safety legislation. They anticipated fewer benefits, expected more barriers and were less likely to use booster seats. Simulations suggest that consistent enforcement coupled with advertising focusing on injury prevention and the use of booster seats by other parents would increase adoption.