Nitrate reduction in a simulated free-water surface wetland system

The feasibility of using a constructed wetland for treatment of nitrate-contaminated groundwater resulting from the land application of biosolids was investigated for a site in the southeastern United States. Biosolids degradation led to the release of ammonia, which upon oxidation resulted in nitrate concentrations in the upper aquifer in the range of 65-400 mg N/L. A laboratory-scale system was constructed in support of a pilot-scale project to investigate the effect of temperature, hydraulic retention time (HRT) and nitrate and carbon loading on denitrification using soil and groundwater from the biosolids application site. The maximum specific reduction rates (MSRR), measured in batch assays conducted with an open to the atmosphere reactor at four initial nitrate concentrations from 70 to 400 mg N/L, showed that the nitrate reduction rate was not affected by the initial nitrate concentration. The MSRR values at 22 °C for nitrate and nitrite were 1.2 ± 0.2 and 0.7 ± 0.1 mg N/mg VSS_COD-day, respectively. MSRR values were also measured at 5, 10, 15 and 22 °C and the temperature coefficient for nitrate reduction was estimated at 1.13. Based on the performance of laboratory-scale continuous-flow reactors and model simulations, wetland performance can be maintained at high nitrogen removal efficiency (>90%) with an HRT of 3 days or higher and at temperature values as low as 5 °C, as long as there is sufficient biodegradable carbon available to achieve complete denitrification. The results of this study show that based on the climate in the southeastern United States, a constructed wetland can be used for the treatment of nitrate-contaminated groundwater to low, acceptable nitrate levels.     

A Best Practice Guide to Resource Forecasting for Computing Systems

Recently, measurement-based studies of software systems have proliferated, reflecting an increasingly empirical focus on system availability, reliability, aging, and fault tolerance. However, it is a nontrivial, error-prone, arduous, and time-consuming task even for experienced system administrators, and statistical analysts to know what a reasonable set of steps should include to model, and successfully predict performance variables, or system failures of a complex software system. Reported results are fragmented, and focus on applying statistical regression techniques to monitored numerical system data. In this paper, we propose a best practice guide for building empirical models based on our experience with forecasting Apache web server performance variables, and forecasting call availability of a real-world telecommunication system. To substantiate the presented guide, and to demonstrate our approach in a step by step manner, we model, and predict the response time, and the amount of free physical memory of an Apache web server system, as well as the call availability of an industrial telecommunication system. Additionally, we present concrete results for a) variable selection where we cross benchmark three procedures, b) empirical model building where we cross benchmark four techniques, and c) sensitivity analysis. This best practice guide intends to assist in configuring modeling approaches systematically for best estimation, and prediction results.     

High-power potassium-titanyl-phosphate (KTP/532) laser vaporization prostatectomy: 24 hours later

All persons 65 years and older are recommended to be immunised against influenza each autumn. As immunisation rates remain low, we conducted a randomised control trial in a three-partner urban general practice to evaluate the differential effectiveness of a single postcard reminder in a general practice setting compared to usual care. All non-residential patients aged 65 years and over were identified from the age/sex/disease register. After exclusions, 325 patients were stratified by sex (125 men and 200 women) and randomised to receive either a postcard reminder in large print mailed in April or usual care. General practitioners (GPs) were blind to the randomisation. A blinded record audit performed in July demonstrated that the postcard was effective in increasing immunisation for men (chi(2)1df = 3.85; p = 0.05) but not for women (chi(2)1df = 0.45; p = 0.50). After adjusting for 1995 immunisation status, the effect of the postcard on immunisation rates was even stronger in men (Wald chi(2)1df = 6.20; p = 0.01) but remained non-significant in women (Wald chi(2)1df = 1.38; p = 0.24). With this adjustment, the odds of having the 1996 flu vaccine for men sent the postcard reminder were three times that of men in the control group (OR = 3.0; 95% CI 1.3-6.9). In a general practice setting, a single postcard reminder appears to be a promising way to boost influenza immunisation rates among ageing men. Replication of the study is recommended.     

The cylindrical banyan multicomputer: A reconfigurable systolic architecture

A new reconfigurable systolic multicomputer architecture is presented. The proposed architecture, called the Cylindrical Banyan Multicomputer (CBM), is based on the structure of a modified banyan network where every node of the network graph is composed of an application processor, a local memory and a communication processor, and network's inputs and outputs are merged (fused). The CBM has one of the lowest (cost) X (delay) among known multicomputer architectures based on regular networks. It is shown that a variety of computation structures such as pipelines, rings, and trees may be constructed and reconfigured in an optimal or a nearby optimal way on the CBM architecture, and that various basic algorithms can be executed very efficiently in a systolic manner. It is also shown that the CBM is an easily diagnosable and fault-tolerant system.     

Analyzing Large Scale Real-World Wireless Multihop Network

We present the results of analysis of Berlin's free multihop wireless network and provide topological, link reliability and traffic statistics we have captured from it. The network is relatively large compared with known wireless multihop networks and testbeds, and it had 316 participating nodes on the average. The observed properties are different from frequently used models: the network is connected but with low average node density, it has large number of bridges (some of them with very low quality of links) and the traffic distribution is highly asymmetrical.     

Stockmayer force constants for the viscosity of polar gases

Relationships have been developed for the calculation of the viscosity of a polar gas at atmospheric pressure from macroscopic parameters available for the substance. The molecular force constants for the Stockmayer potential determined by Monchick and Mason from viscosity data were related to the critical constants of the substance and the parameters ω and × defined through the vapor pressure. For 10 polar gases, an average deviation of approximately 3.0% was obtained between experimental viscosities and values calculated with the relationships of this study. The relationships were also utilized to calculate diffusion coefficients for a number of polar binary mixtures.     

High-power potassium titanyl phosphate laser vaporization prostatectomy

PURPOSE: To determine whether central venous pressure at the common iliac vein reflects right atrial pressure in adult patients. METHODS: In this prospective, non-blinded study 26 mechanically-ventilated adult patients were studied. Simultaneous pressure readings were obtained from the right atrium (TCVP) and the common iliac vein (ACVP). RESULTS: There was a correlation between TCVP and ACVP (r = 0.987; P < 0.0001). The mean difference between TCVP and ACVP was 0.93 mm Hg. And the limits of agreement were: -1.93 to 1.77 mm Hg. CONCLUSION: Venous pressure recorded from the common iliac vein reflects that in the right atrium. Adopting a femoral route for central venous pressure measurement may avoid some of the complications associated with the subclavian route.     

Acute scrotal swelling in Henoch-Sch?nlein syndrome

Freeman-Sheldon's syndrome is a rare genetic disease inherited as an autosomal dominant trait in some families but showing sporadic appearance in the majority of the reported cases. In the present paper we report a family having two affected children from normal consanguineous parents suggesting that Freeman-Sheldon's syndrome may be heterogeneous from the genetic point of view.