The dynamics of microbial growth on soluble substrates: A unifying theory

This paper reviews the literature relevant to the dynamics of microbial growth on soluble substrates and integrates the knowledge obtained into a unifying theory describing that growth. In the unifying theory cellular mass is divided into five constituents: a synthetic component, a structural component, precursor molecules for those components, enzymes catalyzing the synthesis of the precursors, and storage products. Reactions governing the levels of those constituents are hypothesized. The literature shows that the transient response of a culture is generally either a storage response or a growth response and that environmental factors govern which response is manifested. The unifying theory is developed in a way which allows it to be simplified to either of those responses by proper selection of the rate constants in the reactions governing the levels of the cellular constituents.     

Recursion in small storage

An implementation method for procedure calls is discussed which can lead to significant storage space reductions for recursive algorithms.     

Factors influencing deterioration of denitrification by oxygen entering an anoxic reactor through the surface

The purpose of the paper is to examine the factors that influence the deterioration of denitrification in open anoxic reactors. For this investigation an ASM 1-based simulation model was developed and successfully applied to fit data from batch experiments carried out in lab-scale reactor vessels (uncovered and covered) using both clarified domestic wastewater and synthetic wastewater. Applying the verified model, simulation studies were performed to investigate the effects of available denitrifiable substrate, biomass concentration, oxygen transfer rate, and temperature on deterioration of denitrification in open anoxic reactors. It has been shown that oxygen entering an anoxic reactor through the surface may not just affect denitrification metabolically, but also kinetically, due to increased dissolved oxygen (DO) concentration exerting an inhibitory effect on the denitrification rate. When the exogenous substrate concentration in the reactor vessel is high enough for a high consumption rate, the DO concentration is kept low. The higher the biomass concentration, and thereby the consumption rate of endogenous substrate, the lower the DO concentration during the low-rate denitrification phase. At low substrate removal rates, decreasing temperature will cause the DO concentration in anoxic vessels to increase. The results suggest that assuring removal of available exogenous carbon source at high rate by staging of open anoxic bioreactors may significantly improve denitrification efficiency.     

Efficacy of intramammary tilmicosin and risk factors for cure of Staphylococcus aureus infection in the dry period

The objective ofthis study was to evaluate the efficacy of intramammary tilmicosin, administered at drying-off, for eliminating Staphylococcus aureus infection, and to identify risk factors for S. aureus cure during the dry period. A total of 219 naturally infected cows, representing 308 quarters, were randomized to receive either one of two treatments at drying-off. Cows received either an intramammary infusion of 500 mg of benzathine cloxacillin, or a sterile solution containing 1,500 mg of tilmicosin. All cows had quarter milk samples taken aseptically three times before dry-off, and at wk 1, 2, and 4 of the subsequent lactation. Overall, 62% of cows and 67.5% of quarters infected with S. aureus cured during the dry period. The cure following administraton of tilmicosin was 67.3 and 72.5% for cows and quarters, respectively. By comparison, the cure achieved with cloxacillin was 56.9 and 62.9% of cows and quarters. Cows receiving tilmicosin were 2.1 times more likely to cure. The cure rate for cows decreased as the linear score on the last DHI test increased, and as the amount of S. aureus being shed increased. Quarters that cultured positive multiple times before drying-off were less likely to cure. Staphylococcus aureus infections located in front quarters of the udder were 2 times more likely to cure than those in hind quarters. Results of this study demonstrate that intramammary tilmicosin at drying-off is efficacious in curing existing S. aureus during the dry period. Risk factors associated with the cure of S. aureus were identified.     

Personality and mortality risk across the life span: The importance of conscientiousness as a biopsychosocial attribute.

Objective: This study addressed whether personality in childhood and personality in adulthood are independent predictors of mortality risk and the extent to which behavioral and other psychosocial factors can explain observed relationships between personality and mortality risk. Design: This was a prospective longitudinal cohort study of 1,253 male and female Californians over 7 decades (1930-2000). Proportional hazards regressions were the principal analyses. Main Outcome Measures: Mortality risk (in the form of relative hazards) was the primary outcome. Additional tests of mediators and moderators ascertained whether associations between personality and mortality risk remained significant when psychosocial and behavioral variables were statistically controlled. Results: The findings, including a new 14-year additional follow-up in old age, revealed that conscientiousness, measured independently in childhood and adulthood, predicted mortality risk across the full life span. The link from childhood remained robust when adult conscientiousness and certain behavioral variables were controlled. Psychosocial and behavioral variables partly explained the adult conscientiousness-longevity association. Conclusion: The findings demonstrate the utility and complexity of modern personality concepts in understanding health and point to conscientiousness as a key underexplored area for future biopsychosocial studies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An investigation of early research experience and research self-efficacy.

Graduate students in psychology typically report that they either love research or hate research. Despite the fact that most doctoral students in psychology enter some type of clinical practice upon graduation, research is a requirement for all students enrolled in scientist-practitioner programs regardless of their career aspirations beyond graduation. Research advances knowledge in the field of psychology and often guides clinical practice, yet very few psychologists conduct research after graduate school (C. J. Gelso, 1993). Efforts have been undertaken to determine factors that contribute to graduate students' research productivity. One such factor may be research self-efficacy. This study examined the influence of early research experience as a factor to bolster research self-efficacy. Results indicated that supportive peers and mentors contributed to positive research experiences. Additionally, positive team research experiences significantly predicted research self-efficacy. Implications for training programs and students are provided. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spatial dynamics and genetics of infectious diseases on heterogeneous landscapes.

Explicit spatial analysis of infectious disease processes recognizes that host-pathogen interactions occur in specific locations at specific times and that often the nature, direction, intensity and outcome of these interactions depend upon the particular location and identity of both host and pathogen. Spatial context and geographical landscape contribute to the probability of initial disease establishment, direction and velocity of disease spread, the genetic organization of resistance and susceptibility, and the design of appropriate control and management strategies. In this paper, we review the manner in which the physical organization of the landscape has been shown to influence the population dynamics and spatial genetic structure of host-pathogen interactions, and how we might incorporate landscape architecture into spatially explicit population models of the infectious disease process to increase our ability to predict patterns of disease occurrence and optimally design vaccination and control policies.     

应用生态环保设计的新一代真空灭弧室

介绍AREVA"VG"新系列真空灭弧室的短路开断性能和外形尺寸最优化,并且从环保的立场出发,通对过设计过程和制造工艺的全面评审,确认其对生态环境的影响也得到了最优化.新型的AREVA工艺技术减少了制造真空灭弧室所需能源大约40%,减少原材料消耗约30%.这种工艺技术已经应用于工作电压直到38 kV,正常工作电流直到3 150 A和短路电流直到63 kA的新系列真空灭弧室开关装置中.