Current and emerging molecular diagnostic technologies applicable to bacterial food safety

There is an increasing need for rapid test methods to certify the quality and safety of food products. Current tests applied for the microbiological assessment of food products are based on standard approved culture-based isolation methods and can take several days to yield results. Nucleic acid diagnostic (NAD) tests for the identification of bacterial foodborne pathogens employing in vitro amplification technologies are capable of sensitive and specific detection of single or multiple pathogens in foods in a shorter timeframe than traditional methods. New developments in molecular biosensors have the potential to provide at-line bioanalysis, whereas microarray-based technologies may in the future be the NAD platforms of choice for multiple pathogen detection and identification. This article reviews current and emerging NAD platforms for foodborne bacterial pathogens that have the potential to impact food safety.     

BIOFUMIGANT COMPOUNDS RELEASED BY FIELD PENNYCRESS (<Emphasis Type="Italic">Thlaspi arvense</Emphasis>) SEEDMEAL

Defatted field pennycress (Thlaspi arvense L.) seedmeal was found to completely inhibit seedling germination/emergence when added to a sandy loam soil containing wheat (Triticum aestivum L.) and arugula [Eruca vesicaria (L.) Cav. subsp. sativa (Mill.) Thell.] seeds at levels of 1.0% w/w or higher. Covering the pots with Petri dishes containing the soil-seedmeal mixture decreased germination of both species at the lowest application rate (0.5% w/w), suggesting that the some of the phytotoxins were volatile. CH₂Cl₂, MeOH, and water extracts of the wetted seedmeal were bioassayed against wheat and sicklepod (Senna obtusifolia (L.) H. S. Irwin & Barneby) radicle elongation. Only the CH₂Cl₂ extract was strongly inhibitory to both species. Fractionation of the CH₂Cl₂ extract yielded two major phytotoxins, identified by gas chromatography–mass spectrometry and NMR as 2-propen-1-yl (allyl) isothiocyanate (AITC) and allyl thiocyanate (ATC), which constituted 80.9 and 18.8%, respectively, of the active fraction. When seeds of wheat, arugula and sicklepod were exposed to volatilized AITC and ATC, germination of all three species was completely inhibited by both compounds at concentrations of 5 ppm or less. In field studies, where seedmeal was applied at 0.50, 1.25, and 2.50 kg/m² and tarped with black plastic mulch, all of the treatments significantly reduced dry weight of bioassay plants compared to the tarped control, with the highest seedmeal rate decreasing dry matter to less than 10% of the control 30 d after seedmeal application. Field pennycress seedmeal appears to offer excellent potential as a biofumigant for high-value horticultural crops for both conventional and organic growers.Names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard of the product, and the use of the name by USDA implies no approval of the product to the exclusion of others that may also be suitable.     

Neural network identification of critical factors in a dynamic just-in-time kanban environment

Prior research has examined the proper number of kanbans to be used in various just-in-time environments, but relatively little work has been done in exploring which factors internal and external to a shop in a given time period are critical in determining the necessary number of kanbans to be specified for the next period. The research reported here examines the identification of shop factors in a dynamic and stochastic just-in-time environment. In particular, three questions are addressed: does information from a prior period help in setting the kanban level in the current period? If so, which endogenous and exogenous factors considered individually help the most? And finally, what grouping of individual factors is most important in deciding the number of kanbans? The methodology employed is to use artificial neural networks to fit simulated shop data to learn the relationship between prediction factors and overall shop performance. Appropriate non-parametric statistical tests are then used to answer the questions. The answers obtained, although shop specific, may also be generated by firms willing to follow the procedure presented here for conditions specific to their particular operation.     

Expert systems in production and operations management: research directions in assessing overall impact

The use and development of expert systems in public and private organizations continue to increase. Many of these systems are being developed for production and operations management. Unfortunately, the impacts that these systems are having in these environments have, for the most part, not been investigated. Most studies on expert systems to date centre either on the technical aspects or validation issues. No one has taken a systemic view that takes into account both the technical issues and the human issues that will have to be addressed in implementing these systems. This paper seeks to stimulate research into the overall impact of expert systems implementation in production. To this end, fourteen research propositions are developed and presented. In addition, the major variables associated with these propositions are combined into a causal model to show the relationships between them and to reveal an overall perspective of the impacts of expert systems implementation on the production process.     

Allocation of contingency in activity duration networks

This paper describes a method for apportioning contingency in a probabilistic network. It distinguishes between two requirements for contingency: for high variance crucial activities, and for high float noncritical activities. This enables a logical two-step apportionment, the first based upon the idea of ‘cruciality’, which has become established as an important indicator of an activity's importance in risk terms, and the second based upon standard ideas about float. A numerical example is given based on data used by previous work, so that a comparison of the methods can be made.     

EFFECTS OF "DREAM DEPRIVATION" ON DREAM CONTENT: AN ATTEMPTED CROSS-NIGHT REPLICATION.

ATTEMPTED TO REPLICATE, IN A CROSS-NIGHT DESIGN, THE FINDING THAT EARLY-NIGHT REM-SLEEP DEPRIVATION LEADS TO MORE DREAMLIKE LATE NIGHT REM-SLEEP MENTATION. 8 SS WERE REM DEPRIVED ON NIGHT 1 AND PSEUDODEPRIVED ON NIGHT 3, WHILE 8 SS WERE RUN IN THE REVERSE ORDER. REPORTS OF MENTAL CONTENT WERE ELICITED FROM NREM AND REM SLEEP ON NIGHTS 2 AND 4, SS AND "WATCHERS" COMPLETED GOUGH ADJECTIVE CHECK LISTS (ACLS) ON S BEHAVIOR DURING DAYS 2 AND 4. DEPRIVATION PRODUCED NO SIGNIFICANT CHANGES IN WAKING BEHAVIOR, NREM OR REM MENTATION, OR IN THE SLEEP CYCLE. FINDINGS ARE DISCUSSED IN TERMS OF DREAM THEORY AND METHODOLOGICAL PROBLEMS OF DEPRIVATION RESEARCH. DEPRIVATION LOWERED DAYTIME ORAL TEMPERATURE, AND ACL RESPONSES PREDICTED PSYCHOLOGICAL COMPENSATION FROM DEPRIVATION. (19 REF.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

RENEWING PEOPLE AND PLACES: INSTITUTIONAL INVESTMENT POLICIES THAT ENHANCE SOCIAL CAPITAL AND IMPROVE THE BUILT ENVIRONMENT OF DISTRESSED COMMUNITIES

ABSTRACT: The challenges confronting distressed communities in the United States are complex and multifaceted. Communities large and small have been significantly affected by a myriad of social, environmental, and economic forces, including a continuing decline in manufacturing employment, uncontrolled sprawl, and the transition to a global economy. The traditional choice between a “place‐based” theory of redevelopment strategy versus a “people‐focused” theory no longer seems feasible or appropriate. This article outlines sustainable development as an alternative strategy that combines a place‐based development strategy, a human development focus, and an environmentally mindful approach. It posits that there exists a direct positive relationship between the creation of social capital, the redevelopment of the built environment utilizing sustainable development practices, and community‐based organizations in distressed communities. Furthermore, the authors suggest that through community investment—a socially responsible investment strategy—institutions of higher education can facilitate the rebuilding of communities by providing financial capital while gaining a moderate yet secure financial return as well as a substantial social return.     

Strength and Toughness of Continuous-Alumina-Fiber-Reinforced Glass-Matrix Composites

Unidirectional, continuous-fiber composites were fabricated using polycrystalline alumina fibers and four different silicate glass matrices of differing thermal expansion. Fracture toughness measurements, strength measurements, and fractographic analysis of failed specimens are used to identify the failure mechanism. Results show that the elastic modulus mismatch between the matrix and the fibers shields the reinforcing fibers from matrix crack extension, thereby increasing composite toughness without fiber pullout. Fractographic analysis shows that fiber shielding leads to fiber failure ahead of matrix crack. Composite toughness increases linearly with increases in the residual compressive stress in the matrix phase. Ultimate composite strengths are dependent upon thermal-expansion-induced residual stresses and fiber strength.