Sludge to Land: Microbiological Double Standards

The microbiological requirements for enhanced treated sludge in the Safe Sludge Matrix are reviewed and compared with those for foods, which are much less stringent. Quantitative microbial risk analysis shows that the risks to human health from disease transmission through sewage sludge to grazing animals or food crops are very low, indicating that the strict requirements of the Safe Sludge Matrix are not really justifiable.     

A 100-Year Review: A century of change in temperate grazing dairy systems

From 1917 to 2017, dairy grazing systems have evolved from uncontrolled grazing of unimproved pastures by dual-purpose dairy-beef breeds to an intensive system with a high output per unit of land from a fit-for-purpose cow. The end of World War I signaled significant government investments in agricultural research institutes around the world, which coincided with technological breakthroughs in milk harvesting and a recognition that important traits in both plants and animals could be improved upon relatively rapidly through genetic selection. Uptake of milk recording and herd testing increased rapidly through the 1920s, as did the recognition that pastures that were rested in between grazing events yielded more in a year than those continuously grazed. This, and the invention and refinement of the electric fence, led to the development of “controlled” rotational grazing. This, in itself, facilitated greater stocking rates and a 5 to 10% increase in milk output per hectare but, perhaps more importantly, it allowed a more efficient use of nitrogen fertilizer, further increasing milk output/land area by 20%. Farmer inventions led to the development of the herringbone and rotary milking parlors, which, along with the “unshortable” electric fence and technological breakthroughs in sperm dilution rates, allowed further dairy farm expansion. Simple but effective technological breakthroughs in reproduction ensured that cows were identified in estrus early (a key factor in maintaining the seasonality of milk production) and enabled researchers to quantify the anestrus problem in grazing herds. Genetic improvement of pasture species has lagged its bovine counterpart, but recent developments in multi-trait indices as well as investment in genetic technologies should significantly increase potential milk production per hectare. Decades of research on the use of feeds other than pasture (i.e., supplementary feeds) have provided consistent milk production responses when the reduction in pasture intake associated with the provision of supplementary feed (i.e., substitution rate) is accounted for. A unique feature of grazing systems research over the last 70 yr has been the use of multi-year farm systems experimentation. These studies have allowed the evaluation of strategic changes to a component of the system on all the interacting features of the system. This technique has allowed excellent component research to be “systemized” and is an essential part of the development of the intensive grazing production system that exists today. Future challenges include the provision of skilled labor or specifically designed automation to optimize farm management and both environmental sustainability and animal welfare concerns, particularly relating to the concentration of nitrogen in each urine patch and the associated risk of nitrate leaching, as well as concerns regarding exposure of animals to harsh climatic conditions. These combined challenges could affect farmers' “social license” to farm in the future.     

A Bayesian network model to assess the public health risk associated with wet weather sewer overflows discharging into waterways

Overflows from sanitary sewers during wet weather, which occur when the hydraulic capacity of the sewer system is exceeded, are considered a potential threat to the ecological and public health of the waterways which receive these overflows. As a result, water retailers in Australia and internationally commit significant resources to manage and abate sewer overflows. However, whilst some studies have contributed to an increased understanding of the impacts and risks associated with these events, they are relatively few in number and there still is a general lack of knowledge in this area. A Bayesian network model to assess the public health risk associated with wet weather sewer overflows is presented in this paper. The Bayesian network approach is shown to provide significant benefits in the assessment of public health risks associated with wet weather sewer overflows. In particular, the ability for the model to account for the uncertainty inherent in sewer overflow events and subsequent impacts through the use of probabilities is a valuable function. In addition, the paper highlights the benefits of the probabilistic inference function of the Bayesian network in prioritising management options to minimise public health risks associated with sewer overflows.     

Meeting the phosphorus consent with biological nutrient removal under UK winter conditions

It is estimated that up to 342 wastewater treatment plants (Wwtps) in England and Wales will require a phosphorus (P) consent by 2010. Although biological P removal is considered to be the most sustainable option for P removal, it has always been problematic for plants that remove both nitrogen and P due to the inadequate concentration of organic material during wet periods. Two biological nutrient removal (BNR) configurations, the Johannesburg (JHB) process and a combined JHB and five-stage Bardenpho process, were evaluated over a period of 2 years to assess the impact of sewage strength on bio-P removal. The JHB achieved an average effluent total phosphorus (TP) of 2.4 mg/L and the combined JHB and five-stage process averaged 1.4 mg/L effluent TP. The major problems affecting the performance of both configurations were: dissolved oxygen (DO) in the recycled mixed liquor, nitrate in the return activated sludge (RAS) and low influent biological oxygen demand (BOD) concentrations. Acetate dosing proved successful as a source of volatile fatty acids (VFAs) in the anaerobic zone during periods of low-strength sewage. An acetate dosing strategy based on the influent flow rate to the plant was found to be a simple and effective technique that ensured that a consent of <1 mg TP/L could be met.     

Fade slope analysis for Alaska, Florida, and New Mexico ACTSpropagation data at 20 and 27.5 GHz

This paper analyzes fade slope for the Alaska, Florida, and New Mexico Advanced Communications Technology Satellite (ACTS) propagation data at 20 and 27.5 GHz for the first two years of the experiment (December 1, 1993-November 30, 1995). The propagation experiment will continue to collect data for at least another 21 months. Fade slope is examined on a statistical basis for the three sites. The Florida and New Mexico receiver sites have very different weather characteristics but almost identical elevation angles, while the Alaska receiver terminal has an extremely low elevation angle. The cumulative statistics illustrate the relationship between fade slope, fade level, transmission frequency, and elevation angle for all three sites     

Separate and combined effects of a cognitive map and a symbolic code in the learning of a modeled social skill (job interviewing).

Evaluated the incremental effects of a cognitive map (CM) and a symbolic code (SC) treatment (separately and in combination) relative to a standard modeling treatment (SMT) that generated equivalent demand characteristics. SMT in turn was compared to a no-treatment control condition (NT). Simulated job interviews were conducted 3 wks after treatment with 55 undergraduates who had been assigned to 1 of 4 treatments or NT. The Job Interview Rating Scale, knowledge scores, and speaking time were included in the measures of interviewing proficiency. Significant gains were attributable to CM on 4 of 6 social skills criteria. The SC and combination (CM plus SC) treatments produced significant improvement on all dependent variables. Evidence favoring SMT over NT was weak. Cost–benefit implications for the theoretically derived CM and SC treatments are discussed. (30 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Market Dynamics and Local Policy Choices for Converged Systems: Case Study of Integrated Telecommunication Design and Deployment

Researchers have cogently presented the technical case for converged telecommunications systems. However, it is not clear how market-based telecommunications providers and local communities are embracing this technical argument as they design and adopt new telecommunication systems. This paper uses a case study approach to examine market and policy dynamics influencing converged network deployment in a mixed commercial and residential environment. Specifically, the article presents the overall telecommunications design and then analyzes several implementation alternatives proposed for a major urban redevelopment project in the greater Denver metropolitan area. These alternatives range from more traditional telecommunications solutions to fully converged networks. Based on this review, the paper analyzes the role of a layered policy approach to telecommunications regulation at the local level and how interoperability serves as a mediating condition before market convergence is achieved. Finally, the paper addresses public policy implications for encouraging adoption of fiber-IP based networks as well as research directions for assessing metropolitan adoption of converged systems.     

Using Ontologies and Vocabularies for Dynamic Linking

Ontology-based linking offers a solution to some of the problems with static, restricted, and inflexible traditional Web linking. Conceptual hypermedia provides navigation between Web resources, supported by a conceptual model, in which an ontology's definitions and structure, together with the lexical labels, drive the consistency of link provision and the linking's dynamic aspects. Lightweight standard representations make it possible to use existing vocabularies to support Web navigation and browsing. In this way, the navigation and linking of diverse resources (including those not in our control) based on a community understanding of the domain can be consistently managed.     

Correlation of EGTA and calcium-blocking agents on the response of the bladder to in vitro ischemia

The effects of repetitive field stimulation (model of hyperrelexia) on the responses of isolated strips of rabbit urinary bladder to FS and carbachol were evaluated under a variety of incubation conditions. Compared to control conditions, 2 h of repetitive FS in normal, oxygenated Tyrode's solution followed by incubation for 1 h with no stimulation resulted in a 50% decrease in contractile response to FS and a 30% decrease in the response to carbachol. Incubation in the absence of O2 and glucose was used as an in vitro model for ischemia. Repetitive stimulation during in vitro ischemia resulted in a significantly greater decrease in the contractile responses to FS and carbachol than did in vitro ischemia without repetitive stimulation. The magnitude of contractile dysfunctions in response to both stimuli were significantly reduced in the presence of EGTA (calcium chelator), diltiazem (calcium channel blocker) or pincidil (potassium channel opener). Incubation with thapsigargin (SR calcium uptake inhibitor) + ryanodine (SR calcium storage inhibitor) had no effect. The results of these studies indicate that inhibition of Ca2+ entry reduces the contractile dysfunctions induced by repetitive stimulation in the presence of in vitro ischemia. Inhibition of Ca2+i storage and release had no significant effect on the magnitude of contractile dysfunctions induced by repetitive stimulation an in vitro ischemia.