Antibiotics in microbial ecology

Nine strains of the terrestrial bacterial genusXenorhabdus, all isolated as symbionts of nematodes, were examined for their abilities to produce substances with antibiotic activites when grown in pure culture. All nine produced measurable antibiotic activities against one or more of the test strains utilized. The inhibition patterns indicated that different compounds were being produced by the various bacteria. Two of the species that showed particularly strong inhibition patterns were studied in detail. The inhibitory compounds were purified and identified. Strain R produced a mixture of active substances, the major components of which were hydroxyl- and acetoxyl-bearing indole derivatives, presumably produced via tryptophan. Strain Hb, on the other hand, produced only two antibiotics, 4-ethyl- and 4-isopropyl-3,5-dihydroxy-trans-stilbenes, which are presumed to arise via polyketide pathways.     

Fatty Acid and Hydrocarbon Content of Settling Sediments in Lake Michigan

Fatty acid and aliphatic hydrocarbon contents have been examined in sediment collected in traps suspended at three depths at a location in Lake Michigan. Fatty acid distributions are similar at all depths and suggest an authochtonous origin of these materials. Concentrations of acids decrease with greater depths of traps and indicate a combination of active microbial reworking and of dilution by resuspended sedimentary materials. Hydrocarbons in the metalimnion trap contain mostly algal and bacterial components, whereas near-bottom hydrocarbons contain a large land plant contribution, presumably from resuspension of bottom sediments. Comparison of trap contents with fatty acid and hydrocarbons obtained from faunal debris and with published diatom compositions indicates that a mixture of such sources is combined in the organic matter settling in Lake Michigan. Estimated fluxes to the bottom of this part of the lake are 6.5 g/m²/yr for organic carbon, 1.8 g/m²/yr for fatty acids, and 27 mg/m²/yr for aliphatic hydrocarbons.     

Longitudinal models of developmental dynamics between reading and cognition from childhood to adolescence.

The authors applied linear dynamic models to longitudinal data to examine the dynamics of reading and cognition from 1st to 12th grade. They used longitudinal data (N=445) from the Connecticut Longitudinal Study (S. E. Shaywitz, B. A. Shaywitz, J. M. Fletcher, & M. D. Escobar, 1990) to map the dynamic interrelations of various scales of the Wechsler Intelligence Scales for Children--Revised (i.e., Full, Performance, and Verbal) and specific markers of the Woodcock-Johnson Psycho-Educational Battery--Revised reading cluster (i.e., Letter-Word ID, Decoding, and Comprehension). The results of these analyses indicate that (a) there is a positive dynamic relation between reading and cognition across the selected age range; (b) this dynamic relation is symbiotic, with positive influences in both directions; (c) the influence from cognition to reading is stronger when considering the Wechsler Intelligence Scales for Children Performance--Revised Performance scale and weaker with the Verbal scale; (d) when examining the different Reading subtests, the influences from cognition are more apparent for Letter-Word ID and Comprehension and are less perceptible for Decoding; and (e) the dynamics of reading and cognition appear to be of stronger magnitude during 1st to 3rd grade, less strong during 4th to 8th grade, and weaker from 9th to 12th grade. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Developmental lag versus deficit models of reading disability: A longitudinal, individual growth curves analysis.

Individual growth curves were used to test whether the development of children with reading disabilities is best characterized by models of developmental lag or developmental deficit. Developmental changes in reading ability were modeled by using 9 yearly longitudinal assessments of a sample of 403 children classified into three groups representing (a) deficient reading achievement relative to IQ expectations (RD-D), (b) deficient reading achievement consistent with IQ expectations (LA), and (c) no reading deficiency (NRI). Using a model of quadratic growth to a plateau, the age and level at which reading scores plateaued were estimated for each child. Reading-disabled children differed on average from nondisabled children in the level but not in the age at which reading skills plateaued. The RD-D and LA groups did not differ in reading plateau or age at plateau. The subgroup of RD-D children scoring below the 25th percentile in reading differed from LA children only in reading plateau. Results suggest that the developmental course of reading skills in children with reading disability is best characterized by deficit as opposed to lag models. In addition, no support for the validity of classifications of reading disability based on IQ discrepancies was apparent. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

History and status of state natural resource systems

During the 1960's and 1970's there was a trend toward the development of natural resource information systems in state governments encouraged by the need for cost-efficient tools to manage the array of environmental legislation adopted during this period. Additional catalysts included rapidly emerging data management and remote sensing technologies, particularly NASA's Landsat Program. The ultimate success of these systems is dependent upon broad-based political support and their ability to satisfy decision-related needs within each state. Systems tend to be discontinued because of political and economic factors rather than technical problems. The 1980s offer a challenge to utilize excelling technologies for networking capabilities to build consistency, cost-efficiency and effectiveness into resource-related decision-making.     

Training mental health practitioners to assist families of persons who have a psychiatric disability.

Reports on the development, implementation, and evaluation of an 18-hr in-service training program designed to improve the knowledge and change the attitudes practitioners have about families in which there is a member with mental illness. 47 practitioners (aged 26+ yrs) from a community mental health center served as Ss. Comparisons between practitioners who received training (n?=?29) and those who did not suggest that this model is an effective method of training practitioners. Trained practitioners reported more positive attitudes about providing services and information to families and more contact concerning educational and supportive topics. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modernizing Mansaf: The Consuming Contexts of Jordan's National Dish

Mansaf is the national feast dish of Jordan. As such, it is commonly associated with a traditional culture based on an agro-pastoral lifestyle in which meat and yogurt were readily available and hosts had ample time to attend to the needs of guests. This nostalgic ideal is not representative of contemporary Jordanian experience, yet mansaf remains—especially for those of Bedouin origin—the most appropriate measure of a host's respect for “his” guests. The relationship between mansaf as a domestic product and mansaf as a national icon are examined here in historical and contemporary contexts. Utilizing diverse source materials, I analyze the reactions of Jordanian Bedouin to general efforts to commodify, rationalize, and nationalize the meaning, making, and political utility of mansaf. This process sheds light on current analytical engagements with modernity, public culture, tourism, and the performance of national identity.     

Factor structure for Young’s Internet Addiction Test: A confirmatory study

A number of diagnostic scales have been developed in recent years to assess Internet addiction. To better understand the structure, validity, and reliability of such assessment instruments, Young’s Internet Addiction Test (IAT) was evaluated using a confirmatory approach.Data collected through a survey of 410 Hong Kong university undergraduates was subjected to exploratory factor analysis and data from a hold-out sample was analyzed using confirmatory factor analysis in order to assess the psychometric properties and factor structure of the IAT scale. Three dimensions, namely, “Withdrawal and Social Problems”, “Time Management and Performance”, and “Reality Substitute” were extracted.These dimensions were then correlated with a number of criterion variables, including academic performance, online activities, gender, and Internet usage. The results show that academic performance was negatively correlated with the Internet addiction scores. The degree of Internet addiction was also found to vary across different types of online activity, with people engaged in cyberrelationships and online gambling having higher Internet addiction scores.     

Super-resolution image reconstruction for a steerable array of sub-imagers

Super-resolution image reconstruction has many different application areas. A thin flat-form factor camera can use arrays of small low-resolution imagers with dynamic control of the overlapping fields-of-view to theoretically achieve arbitrarily fine resolution in some parts of a reconstructed image in a noise-free environment. Diversity in the structure of the sub-imagers has been shown to improve performance in medium and low noise environments and also to allow local reconstruction which lowers computational requirements. Analysis in both the space domain and spatial frequency domain of the relationship of measurement noise level and resolution improvement factor on performance explains the behavior of systems with diverse magnification and orientation. Simulations show expected performance over a range of relevant noise levels, and image examples are used to demonstrate results.