Surface charge--induced ordering of the au(111) surface

Synchrotron surface x-ray scattering (SXS) studies have been carried out at the Au(lll)/electrolyte interface to determine the influence of surface charge on the microscopic arrangement of gold surface atoms. At the electrochemical interface, the surface charge density can be continuously varied by controlling the applied potential. The top layer of gold atoms undergoes a reversible phase transition between the (1 x 1) bulk termination and a (23 x radical3) reconstructed phase on changing the electrode potential. In order to differentiate the respective roles of surface charge and adsorbates, studies were carried out in 0.1 M NaF, NaCl, and NaBr solutions. The phase transition occurs at an induced surface charge density of 0.07 +/- 0.02 electron per atom in all three solutions.     

Crystal structure of the RC-LH1 core complex from Rhodopseudomonas palustris

The crystal structure at 4.8 angstrom resolution of the reaction center-light harvesting 1 (RC-LH1) core complex from Rhodopseudomonas palustris shows the reaction center surrounded by an oval LH1 complex that consists of 15 pairs of transmembrane helical alpha- and beta-apoproteins and their coordinated bacteriochlorophylls. Complete closure of the RC by the LH1 is prevented by a single transmembrane helix, out of register with the array of inner LH1 alpha-apoproteins. This break, located next to the binding site in the reaction center for the secondary electron acceptor ubiquinone (UQB), may provide a portal through which UQB can transfer electrons to cytochrome b/c1.     

Crop management based on field observations: Case studies in sugarcane and coffee

For millennia farmers have continually improved their crop management and production practices through their observations and experience. More recently modern science and research methods based on controlled experiments became the most visible instrument of technological change in agriculture, nevertheless farmers continued to develop and implement new technologies based on their own observations made under commercial conditions. Modern information technology and social organization of producers make it possible to use operational research, which is based on the observation and analysis of operations so as to improve them, to manage crops better. The article describes two cases, coffee and sugarcane, in which observation of the results obtained by farmers, with the natural variation in the environment and the distinct management practices they apply can be used to determine site specific crop management practices. The basis of the methodology is to (a) obtain data from a series of cropping events that characterizes the conditions under which each crop is grown, how it is managed and how it performs under commercial conditions (data capture), (b) to manage and analyze the data in centralized databases (data management and analysis) and (c) make the information derived from the data analysis available to growers so that they can use it to make better informed decisions (interpretation). All aspects of the methodology depend on the social organization of the growers and the supply chain of which they form a part, and hence social organization is an integral part of the methodology.The processes of characterization of the growing conditions, including both environmental and management parameters, the establishment of databases, the data analysis and interpretation, and mechanisms of interacting with producers are described with emphasis on the importance of social organization and farmers’ groups. Examples are given of how this approach can be used to better understand the crop response to variation in the environment and management, and how this can be used by farmers to improve productivity and quality in two contrasting crops. The paper demonstrates that operational research can be used to evaluate farmers’ experiences and to share that knowledge amongst them so as to improve their production practices in the context of their particular environment. It is suggested that the operation research approach is particularly effective in heterogeneous landscapes with perennial crops that have not been the subject of intense research. Furthermore operational research is effective in determining the crop response to variables that are not readily studied in small plots and in determining optimal combinations of multiple variables. Producers believe in the results obtained as there are none of the problems of scaling up from experimental plots to commercial conditions. It is proposed that the approaches described can readily be applied to other crop species.     

Ocean energy: forms and prospects

The nature and distribution of power sources of the sea other than petroleum are discussed, along with possible entrées for their use. Waves, tides, currents, and salinity and temperature gradients all have the potential to contribute useful power. Submarine geothermal sources, salt domes, ice, and other marine-associated concentrations may be more important. There are opportunities to employ these marine power resources directly rather than for contributions to power grids or power-intensive products. Ancillary employment of the seawater as a coolant and of the sediments below the seabed for the disposal of nuclear wastes may be even more important uses than employment of the power that the sea contains.     

Evaluation of Serum and Seminal Plasma Markers in the Diagnosis of Canine Prostatic Disorders

Serum and seminal plasma concentrations or activities of acid phosphatase (AP), prostate specific antigen (PSA), and canine prostate specific esterase (CPSE) were measured in normal dogs, dogs with benign prostatic hyperplasia (BPH), dogs with bacterial prostatitis, and dogs with prostatic carcinoma to determine if these assays would be of value in differentiating dogs with prostatic carcinoma from normal dogs, and dogs with other prostatic disorders. In addition, tissue sections of prostatic adenocarcinomas were stained with antiprostatic AP, anti-CPSE, and anti-PSA antibodies to determine if these would be suitable immunohistochemical markers of prostatic carcinoma. Prostate-specific antigen was not detected in canine serum or seminal plasma. Serum and seminal AP activities did not differ significantly between normal dogs and those with prostatic diseases, or among dogs with different prostatic disorders. Serum CPSE activities were significantly higher in dogs with BPH than in normal dogs. Mean serum CPSE activities in dogs with BPH, bacterial prostatitis, and prostatic carcinoma were not significantly different from each other. Slight to moderate immunohistochemical staining of canine prostatic adenocarcinomas was noted for prostatic AP and PSA; most tumors did not stain for CPSE. These results show that proteins of prostatic origin appear in the serum of dogs as a result of prostatic pathology, especially BPH. Canine prostatic adenocarcinoma does not appear to be associated with significant increases in CPSE or AP activities, possibly because of down-regulation of these enzymes by prostatic carcinoma cells. It is also possible that failure to detect significant differences resulted from limited statistical power for some groups and pairwise analyses because of the small number of dogs evaluated.