Response of the anaerobic fluidized bed reactor to transient changes in process parameters

Anaerobic fluidized bed reactors treating a high strength dairy type waste water were subjected to transient decreases in temperature and increases in influent flowrate or COD for 4 and 8 h periods. The quality of the effluent deteriorated during a shock load but returned to normal steady state values 6–22 h after original conditions had been restored, the stability of the reactor during increases in influent COD were found to be influenced by the bicarbonate buffering capacity of the feed.     

Approximate pattern matching in a pattern database system

This work is concerned with the organization of a large database of binary pictures (normalized for size, rotation and position) and with the efficient “inexact match” of an input pattern against the whole database. Current techniques in pattern analysis use matching algorithms without any regard to the global organization of the storage representations of the models they are to match. Consequently, the algorithms are only practical for small databases. This paper discusses the design of a pattern database system and the economy that it provides for the matching problem. The database organization is based on the quad-tree representation of binary patterns. Given an arbitrary decomposition D (or partition) of a pattern P and an arbitrary function f on the pattern, we repeatedly apply f on D(P), D(D(P))P, … to obtain higher and higher levels of abstraction f(D)(P)), f(D(D(P))), … of the pattern. The computed values obtained after the jth application of f are used to label the ith level of the pyramid. The specific representation used in this paper is called the sum-quad-tree, in which each level of the tree stores the sum of the labels of its sons. The lowest level of the sum-quad-tree corresponds to the individual pixels and is the nth level (i.e. node m at level n implies v(m) = 0 or v(m) = 1). Nodes at the jth level of the sum-quad-tree correspond to sums of 2^n?j × 2^n?j picture points, so that the 0th level contains the number of 1's in the pattern. The pyramid representation is used as a hierarchical (n-level) indexing scheme of the database. The advantage of this organization is that the matching algorithms presented reject most of the patterns in the database by utilizing the relatively small in size index tables and thus avoid the overhead of unnecessary CPU time and $\text{I}\text{O}$ operation between main memory and secondary storage.     

The 1981–1984 automobile fuel economy standards—Can they be achieved?

The current automobile fuel economy standards were established in June 1977. Several studies completed since then recommended that the Department of Transportation (DOT) modify the current schedule. However, all of the studies were completed before the 1979 gasoline shortage.This paper compares the studies performed to assess alternative schedules and identifies major differences. Major differences among the studies include the definition of‘economic practicability’, cost estimates, estimates of automobile sales losses, and the impact of EPA test procedures.The results of the comparison, along with an analysis of the mix of new cars sold and used car prices since the gasoline shortage, are used to determine if the current schedule can be achieved. Observations regarding improvements to the fuel economy programme for establishing post-1985 standards are also presented.     

The effects of environmental information and decision unit structure on felt tension.

Treated 4 measures of felt tension, derived from a factor analysis of the R. L. Kahn et al (1964) tension index, as variables dependent on information inputs from the environment and on the group structure of the decision unit. In an experimental simulation of a military conflict, information load and information specificity were manipulated to control the environment of 48 3-man decision groups (72 ROTC students and 72 US Air Force Academy cadets) structured as either committees of coequals or 2-level hierarchies. Salient findings from the analysis suggest that (a) "role overload tension" is positively related to information load, while "generalized tension" is positively related to information load only when information specificity is low; (b) "information deprivation tension" is inversely related to information specificity for bureaucratically structured groups but not for unstructured groups, and "generalized tension" is inversely related to information specificity only at high information loads; and (c) "role overload tension" and "role ambiguity tension" are lower in groups with a structured hierarchy. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Use of site-directed mutagenesis to obtain isomorphous heavy-atom derivatives for protein crystallography: cysteine-containing mutants of phage T4 lysozyme

Five different cysteine-containing mutants of the lysozyme frombacteriopbage T4 were used to explore the feasibility of usingsite-directed mutagenesis to generate isomorphous heavy-atomderivatives for protein crystallography. Cysteines 54 and 97,present in wild-type lysozyme, can be readily reacted with mercuricion to produce an excellent isomorphous heavy-atom derivative.Mutants with an additional cysteine at position 86,146,153 or157, or with Cys 97 replaced by Val, were engineered by site-directedmutagenesis. The mutant lysozyme Thr 157 - Cys reacts with mercuricchloride to give an excellent new derivatve although Cys 157is only -60% substituted with the heavy atom. The cysteine atposition 146 is largely buried but reacts readily with mercuricchloride. In this case the isomorphism is poor and the resultantderivative is of marginal quality. Cys 153 reacts rapidly withmercuric ion but the derivative crystals do not diffract. Themutant Pro 86 - Cys does not yield a particularly good heavy-atomderivative. This is due in part to a loss of isomorphism associatedwith the mutation. In addition, Cys 86 shows very little reactivitytowards mercurials even though it is fully exposed to solvent.The mutation Cys 97 Val was used to explore the possibilityof creating an independent derivative by deleting a heavy-atomsite already present in wild-type lysozyme. In all cases thatwere tested, the quality of the heavy-atom derivative was improvedby using as an isomorphous pair mercury-substituted mutant versusnon-substituted mutant rather than mercury-substituted mutantversus (non-substituted) wild-type lysozyme. Unexpectedly, thecysteines that are most exposed to solvent and most mobile areleast reactive toward mercuric chloride. The cysteines thatprovide the best heavy-atom sites are those that are locatedin surface crevices and are only partly exposed to solvent.     

Age-related declines in basic social perception: Evidence from tasks assessing eye-gaze processing.

Previous research has investigated age differences in complex social perception tasks such as theory of mind and emotion recognition, with predominant findings of age-related declines. The present study investigated whether there are also age-related changes in basic aspects of social perception. Individuals' ability both to detect subtle differences in eye-gaze direction (e.g., where someone is looking in the environment) and to subsequently use these gaze cues to engage in joint attention with others was assessed. Age-related declines were found in the detection of the most subtle differences in gaze aversion. The ability to engage in joint attention by following gaze cues also declined with age. These age differences were not solely attributable to age impairments in visual perception and visual attention. The potential role of age-related neural declines in social perception problems was considered, along with the implications that age deficits in these basic social skills may have for older adults' social perception. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Physico-chemical Properties of Cinchona Alkaloids Responsible for their Unique Performance in Chiral Catalysis

The physico-chemical properties of cinchona alkaloids have been characterized in connection to their use for catalytic enantioselective conversions. Adding to the previous identification of their active site at the nitrogen atom in the quinuclidine ring and the chiral environment provided by the carbon centers of the neighboring alcohol linker, an argument is made here for the importance of the adoption of certain rotational conformations by those cinchona alkaloids in optimizing their chiral promotion. Because catalysis with cinchona alkaloids involves a liquid phase, there is a dynamic conformation isomerization process controlled by a number of factors having to do with the exact structure of the cinchona as well as with the nature of the solvent used and, in the case of heterogeneous catalysis, the presence of a solid surface. Solvents of intermediate polarity have been found to be the best for dissolving the cinchona, for establishing rapid adsorption equilibria with metal surfaces, and for promoting chiral catalysis. Protonation also leads to a dramatic change in performance, locking the cinchona molecule in a specific conformation held in place by the counter anion of the acid used, and modifying the chemical and biological activity of the system. Comparative studies with several cinchona indicate that molecular groups attached to peripheral positions also exert a great influence on the conformational and adsorption behavior of these molecules.