Social-environmental factors in unipolar depression: Comparisons of depressed patients and nondepressed controls.

Examined the role of stress and coping factors in depression by comparing a group of 409 Ss (over age 18) entering psychiatric treatment for unipolar depression with a sociodemographically matched group of 409 nondepressed Ss. In addition to reporting significantly more stressful events than controls, depressed Ss also experienced more severe life strains associated with their own and their family members' physical illness, their family relationships, and their home and work situations. Depressed Ss were less likely to use problem-solving and more likely to use emotion-focused coping responses and had fewer and less supportive relationships with friends, family members, and co-workers. These group differences were consistent for both depressed women and men. Findings indicate the value of expanding the consideration of psychosocial factors in depression to include individuals' chronic strains and acute stressors as well as their coping responses and social resources. (53 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neighborhood detection using mutual information for the identification of cellular automata.

Extracting the rules from spatio-temporal patterns generated by the evolution of cellular automata (CA) usually requires a priori information about the observed system, but in many applications little information will be known about the pattern. This paper introduces a new neighborhood detection algorithm which can determine the range of the neighborhood without any knowledge of the system by introducing a criterion based on mutual information (and an indication of over-estimation). A coarse-to-fine identification routine is then proposed to determine the CA rule from the observed pattern. Examples, including data from a real experiment, are employed to evaluate the new algorithm.     

Sources of polycyclic aromatic hydrocarbons and hexachlorobenzene in spruce needles of eastern Alaska

The concentrations of phenanthrene, anthracene, fluoranthene, pyrene, benzo[a]anthracene, chrysene, and hexachlorobenzene (HCB) were measured in spruce needles at 36 sites in eastern Alaska during early spring. Concentrations of each polycyclic aromatic hydrocarbon (PAH) varied by an order of magnitude. Samples taken from near the city of Fairbanks had higher concentrations than samples taken from more rural areas. Anthropogenic activities near Fairbanks are most likely a source of PAHs. Variation in the concentration ratios of isomeric PAHs indicates the relative importance of combustion and petrogenic sources. The relative combustion contribution is largest in coastal samples and smallest near Fairbanks. In contrast, the concentration of HCB varied by only a factor of 2. Lipid content of needles and distance from the coast were the major factors correlated with the concentration of HCB.     

Strategies for designing distributed systems: case studies in the design of an air traffic management system

The air traffic management system in the USA is an example of a distributed problem-solving system. It has elements of both cooperative and competitive problem-solving. It includes complex organizations such as Flight Operations Centers, the FAA Air Traffic Control Systems Command Center (ATCSCC), and traffic management units at en route centers that focus on daily strategic planning, as well as individuals concerned more with immediate tactical decisions (such as air traffic controllers and pilots). The design of this system has evolved over time to rely heavily on the distribution of tasks and control authority in order to keep cognitive complexity manageable for any one individual operator, and to provide redundancy (both human and technological) to serve as a safety net to catch the slips or mistakes that any one person or entity might make. Within this distributed architecture, a number of different conceptual approaches have been applied to deal with cognitive complexity and to provide redundancy. These approaches can be characterized in terms of the strategy for distributing: (1) control or responsibility, (2) knowledge or expertise, (3) access to data, (4) processing capacity, and (5) goals and priorities. This paper will provide an abstract characterization of these alternative strategies for distributing work in terms of these 5 dimensions, and will illustrate and evaluate their effectiveness in terms of concrete realizations found within the National Airspace System.     

Function of protonatable residues in the flagellar motor of Escherichia coli: a critical role for Asp 32 of MotB

Rotation of the bacterial flagellar motor is powered by a transmembrane gradient of protons or, in some species, sodium ions. The molecular mechanism of coupling between ion flow and motor rotation is not understood. The proteins most closely involved in motor rotation are MotA, MotB, and FliG. MotA and MotB are transmembrane proteins that function in transmembrane proton conduction and that are believed to form the stator. FliG is a soluble protein located on the cytoplasmic face of the rotor. Two other proteins, FliM and FliN, are known to bind to FliG and have also been suggested to be involved to some extent in torque generation. Proton (or sodium)-binding sites in the motor are likely to be important to its function and might be formed from the side chains of acidic residues. To investigate the role of acidic residues in the function of the flagellar motor, we mutated each of the conserved acidic residues in the five proteins that have been suggested to be involved in torque generation and measured the effects on motility. None of the conserved acidic residues of MotA, FliG, FliM, or FliN proved essential for torque generation. An acidic residue at position 32 of MotB did prove essential. Of 15 different substitutions studied at this position, only the conservative-replacement D32E mutant retained any function. Previous studies, together with additional data presented here, indicate that the proteins involved in motor rotation do not contain any conserved basic residues that are critical for motor rotation per se. We propose that Asp 32 of MotB functions as a proton-binding site in the bacterial flagellar motor and that no other conserved, protonatable residues function in this capacity.     

Differential binding of HMG1, HMG2, and a single HMG box to cisplatin-damaged DNA

The HMG box domain is a DNA binding domain present in the nonhistone chromosomal proteins HMG1 and HMG2 and in other proteins involved in the regulation of gene expression. Previous studies have demonstrated that HMG1 and HMG2 bind with high affinity to DNA modified with the cancer chemotherapeutic drug cisplatin (CDDP). In this report, we compare the binding of full-length HMG1 and HMG2 and the HMG boxes present in these proteins to that of CDDP-DNA. Complexes between HMG1, HMG2, or HMG Box A + B and CDDP-DNA were stable at > or = 500 mM salt, while complexes between a single HMG box and CDDP-DNA exhibited decreased stability. Analysis of a series of HMG1 Box A mutant constructs revealed different affinities for CDDP-DNA. Two constructs containing a Phe to Ala substitution at position 19 and a Tyr to Gly substitution at position 71, are noteworthy; these peptides exhibited reduced affinity for CDDP-DNA. We have generated a structure of HMG1 Box A and used it, along with the results of our binding studies, to model its interaction with CDDP-DNA. HMG1 Box A binds in the minor groove of CDDP-DNA, in agreement with earlier studies. Our model predicts that Tyr71 partially intercalates and forms an H bond with the sugar-phosphate backbone. The model also suggests that Phe 19 does not directly interact with DNA, and hence an Ala substitution at position 19 may alter protein structure. This model should provide a framework for future studies examining HMG Box-DNA interactions.     

Discrimination and classification of buried unexploded ordnance using magnetometry

Magnetic surveys are quite successful at locating buried steel objects, including unexploded ordnance (UXO). However, many of the anomalies apparent in a magnetic image of a contaminated area are from metallic debris, shrapnel, and geological variations in ferromagnetic concentration. Observations are usually made in the far-field of the object so that, in most cases, we can only recover the dipole moment of a buried item. Due to self-demagnetization effects, the magnitude and direction of induced magnetism varies significantly with ordnance orientation. This results in an infinite number of ordnance-like objects that can reproduce a given dipole moment. To discriminate, we define a library of ordnance items expected to occur in the area and find how closely each recovered moment matches one of the UXOs in this library. We define the size of this mismatch as the remanent magnetization and produce a prioritized dig-list on the assumption that items with lower remanence are more likely to be UXO. Such a ranking scheme proves to be very effective when implemented at two sites in Montana. The analysis reveals that live-site and emplaced UXO have significantly different remanence and implies that previous tests of magnetic discrimination performance on seeded sites have been overly pessimistic.     

Use of path analysis in industrial/organizational psychology: Criticisms and suggestions.

Path analysis or structural equation modeling is a technique for testing the consequences of proposed causal relationships among a set of variables. The technique rests on specific procedures and important assumptions (uncorrelated residuals, 1-way causality, linearity, additivity, interval measures). These assumptions, along with the problem of multicollinearity, are discussed, and specific techniques are offered to deal with them. Path analysis studies from the industrial/organizational psychology literature are reviewed to illustrate the specific consequences of disregarding these assumptions and procedures. The relationship between cross-lagged correlation and path analysis is explored, particularly with regard to the differing but complementary purposes of each. Finally, the problems due to both shared and random measurement error and the application of path analysis to experiments are discussed. (37 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Antibiotic lock solutions allow less systemic antibiotic exposure and less catheter malfunction without adversely affecting antimicrobial resistance patterns

There are current concerns that antibiotic lock solutions (ABL) can induce antimicrobial resistance in long‐term hemodialysis patients. Retrospective chart review of 157 children on hemodialysis between January 1997 and June 2006 was performed. In ERA I, only systemic antibiotics were used. In ERA II, ABL were added to systemic antibiotics when needed. In ERA III, ABL were used for treatment of all cases of catheter‐related bacteremia (CRB) and for CRB prophylaxis in high‐risk patients. The study includes 111,325 catheter days. The CRB incidence was 3.9 CRB/1000 catheter days. There was significant decrease for the total systemic antibiotic exposure (P = 0.0484) and the percentage of catheters lost to malfunction (P = 0.001) in ERA III. Protocol ABL exposure was associated with a trend to increased tobramycin‐gentamicin resistance for gram‐positive CRBs (P = 0.2586) but with improved tobramycin‐gentamicin resistance for gram‐negative (P = 0.0949) and polymicrobial CRBs (P = 0.1776) and improved vancomycin resistance for gram‐positive CRBs (P = 0.0985). This retrospective analysis does not support the premise that ABL use will promote antimicrobial resistance in the hemodialysis population. The decreased exposure to systemic antibiotics by vigorous ABL use may even improve the antimicrobial resistance patterns in this population in the long term.