Integrable devices for wavelength multiplexing optical communication systems

Devices for wavelength division multiplexing (wdm) applications become very important in today’s communication systems. Here the operation principle and the main characteristics of some key components in wdm-systems are given. Various types of tunable lasers, wavelength converters and tunable filters are discussed.     

Electrochemical decomplexing and oxidation of organic (chelating) additives in effluents from surface treatment and metal finishing

The electrochemical decomplexing and oxidation of two frequently used complexing agents in surface treatment and metal finishing—EDTA (ethylenediaminetetraacetic acid) and NTA (nitrilotriacetic acid)—and of organic non‐complexing additives used in nickel‐plating baths were the subject of this study. Using a Ti–RuO₂ electrode, a partial indirect oxidation by in‐situ electrochemical generation of chlorine compounds could be achieved for EDTA and NTA. At a boron‐doped diamond (BDD) electrode however, complete decomplexing and high COD (Chemical Oxygen Demand) and TOC (Total Organic Carbon) (up to 95%) removal occurred at an average current density of 2 A dm^?2. It is shown that direct electrochemical oxidation at a BDD electrode resulted in lower energy consumption and higher treatment rates than indirect oxidation at a Ti–RuO₂ electrode. Decomplexing at the BDD electrode occurred at high current efficiencies ranging from 71% to 95% with decomplexing rates in the order of 3.13 mmol (Ah)^?1 and 5.02 mmol (Ah)^?1 for EDTA and NTA respectively. COD removal rates obtained were 0.090 g (Ah)^?1 for EDTA, 0.100 g (Ah)^?1 for NTA and 0.205 g (Ah)^?1 for the nickel‐plating additives. Electrochemical decomplexing and oxidation of common chelating agents can render the subsequent metal precipitation and biological wastewater treatment of surface treatment and metal finishing effluents more efficient. Copyright © 2003 Society of Chemical Industry     

Ground beetle habitat templets and riverbank integrity

The habitat templet approach was used in a scale‐sensitive bioindicator assessment for the ecological integrity of riverbanks and for specific responses to river management. Ground beetle habitat templets were derived from a catchment‐scale sampling, integrating the overall variety of bank types. This coarse‐filter analysis was integrated in the reach‐scale fine‐filtering approaches of community responses to habitat integrity and river management impacts. Higher species diversity was associated with the higher heterogeneity in bank habitats of the un‐navigable river reaches. The abundant presence of habitat specialists in the riverbank zone allows a habitat integrity assessment based on the habitat templet indicator species. Significant responses were detected for channel morphology in the width‐to‐depth ratio and for hydrological regime in peak frequency and peak velocity, enabling the development of evaluation methods for the impact assessment of river management and flood protection strategies. Copyright © 2005 John Wiley & Sons, Ltd.     

Exposure to physical movement in low back pain patients: Restricted effects of generalization.

Whether the effects of exposure to 1 movement generalize to another dissimilar movement was investigated in 37 patients with low back pain (15 men, 22 women). Two movements were executed twice: bending forward while standing and lifting 1 leg while lying down. During each trial, baseline pain, expected pain, and experienced pain were recorded. Similar ratings for perceived harm were obtained. Analyses revealed an initial overprediction of pain, but after exposure the overprediction was readily corrected. This exposure effect did not generalize toward another dissimilar movement. These results were only characteristic for patients with catastrophic thinking about pain. Low pain catastrophizers did not overpredict pain. There were no effects of exposure on perceived harm. Exposure may profitably be conceived of as the learning of exceptions to a general rule. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Very-high resolution side-scan sonar mapping of biogenic reefs of the tube-worm Lanice conchilega

Reefs of the tube-building polychaete Lanice conchilega are known to represent hotspots of biodiversity within inter- and subtidal soft sediments of the North Sea. However, because of their patchy distribution, point sampling does not appropriately map their subtidal spatial distribution. This study evaluated the feasibility to detect L. conchilega reefs by very-high resolution side-scan sonar imagery. A subtidal very-high resolution (410 kHz) side-scan survey, combined with grab sampling, revealed high densities of L. conchilega (up to 1979 ind. m^? 2) to coincide with a higher reflectivity, patchy and grainy acoustic facies. From the side-scan sonar imagery, individual reefs were estimated to reach a maximum size of 15 m². To ground truth the acoustic facies, the distribution of intertidal L. conchilega reefs was mapped at low tide and side-scan sonar imagery was recorded during the following high tide. Intertidal L. conchilega reefs had a patch size of 0.8 m² up to 11.6 m², elevated 7.5 to 11.5 cm above the surrounding seafloor and covered approximately 10% of the selected area. The very-high (445 kHz) resolution side-scan sonar imagery revealed a similar acoustic facies as in the subtidal. Lower-resolution (132 kHz) side-scan sonar imagery was less efficient to detect physically less developed L. conchilega reefs. We conclude that (1) there are no major technical restrictions to map L. conchilega reefs using side-scan sonar, (2) the developmental stage of L. conchilega reefs impacts the detectability of the reefs, and (3) very-high resolution side-scan sonar imagery is considered a necessity when mapping small-scale structures, such as L. conchilega reefs.     

Building an Association Rules Framework to Improve Product Assortment Decisions

It has been claimed that the discovery of association rules is well suited for applications of market basket analysis to reveal regularities in the purchase behaviour of customers. However today, one disadvantage of associations discovery is that there is no provision for taking into account the business value of an association. Therefore, recent work indicates that the discovery of interesting rules can in fact best be addressed within a microeconomic framework. This study integrates the discovery of frequent itemsets with a (microeconomic) model for product selection (PROFSET). The model enables the integration of both quantitative and qualitative (domain knowledge) criteria. Sales transaction data from a fully automated convenience store are used to demonstrate the effectiveness of the model against a heuristic for product selection based on product-specific profitability. We show that with the use of frequent itemsets we are able to identify the cross-sales potential of product items and use this information for better product selection. Furthermore, we demonstrate that the impact of product assortment decisions on overall assortment profitability can easily be evaluated by means of sensitivity analysis.     

Evaluation of corn cob mix in organic finishing pig nutrition

Two consecutive experiments were performed to evaluate corn cob mix (CCM) inclusion in an organic diet. The experiments were performed in an organic barn on nine pens of four pigs (two barrows and two sows) of commercial breeds from 45 kg to slaughter. In the first experiment, an organic concentrate was mixed with organic CCM‐silage to obtain three concentrate:CCM ratios of 1:0, 4:1 and 3:2 (w:w). In the second experiment, three concentrates were produced to obtain diets with equal nutrient levels on a dry matter basis after 0, 200 and 400 g kg^?1 CCM inclusion respectively. In all groups of both experiments, meat and carcass traits were comparable with common practice and differences between treatment groups were not seen. Feed conversion ratio on an as‐fed basis was worse with higher CCM levels in the diet, most likely due to the dilution effect by the lower dry matter content of CCM. In the first experiment, pigs on a higher concentrate:CCM ratio showed a higher feed intake, indicating a compensation for the lower energy density of these diets. In the second experiment, the 400 g kg^?1 CCM group showed a lower daily dry matter intake (p = 0.048) leading to slower growth (p = 0.015). This indicated a bulk effect of the CCM in this case. In conclusion, lean carcasses with good meat quality can be obtained even in situations where up to 400 g kg^?1 organic CCM‐silage is included in a balanced organic pig fattening diet. Moreover, a bulk effect of CCM‐silage can be used in some cases to limit the typically high dry matter intake in outdoor pig fattening, thereby preventing excessive fat accretion. Copyright © 2005 Society of Chemical Industry     

Traffic accident segmentation by means of latent class clustering

Traffic accident data are often heterogeneous, which can cause certain relationships to remain hidden. Therefore, traffic accident analysis is often performed on a small subset of traffic accidents or several models are built for various traffic accident types. In this paper, we examine the effectiveness of a clustering technique, i.e. latent class clustering, for identifying homogenous traffic accident types. Firstly, a heterogeneous traffic accident data set is segmented into seven clusters, which are translated into seven traffic accident types. Secondly, injury analysis is performed for each cluster. The results of these cluster-based analyses are compared with the results of a full-data analysis. This shows that applying latent class clustering as a preliminary analysis can reveal hidden relationships and can help the domain expert or traffic safety researcher to segment traffic accidents.     

Effect of hydroxyl ions on chloride penetration depth measurement using the colorimetric method

In this paper, the effect of hydroxyl ions on chloride penetration depth measurement using the colorimetric method was studied. Equivalent silver nitrate solution (i.e. Ag⁺ = Cl⁻) was added to the NaCl + NaOH solution with different concentrations, then the amount of precipitated silver chloride and silver oxide were determined by chemical methods, and the color of the precipitated products was examined. Results show that the amount of silver chloride formed decreases linearly as OH⁻ to Cl⁻ ratio (r) increases. Thus, the chloride concentration at color change boundary changes with the pH value of the concrete. AgCl has a white color, while Ag₂O has a dark brown color. When the value of r exceeds 4, the color of the mixture looks brown, and color change boundary cannot be easily distinguished.     

Evaluating time to cancer recurrence as a surrogate marker for survival from an information theory perspective

The last two decades have seen a lot of development in the area of surrogate marker validation. One of these approaches places the evaluation in a meta-analytic framework, leading to definitions in terms of trial- and individual-level association. A drawback of this methodology is that different settings have led to different measures at the individual level. Using information theory, Alonso et al. proposed a unified framework, leading to a new definition of surrogacy, which offers interpretational advantages and is applicable in a wide range of situations. In this work, we illustrate how this information-theoretic approach can be used to evaluate surrogacy when both endpoints are of a time-to-event type. Two meta-analyses, in early and advanced colon cancer, respectively, are then used to evaluate the performance of time to cancer recurrence as a surrogate for overall survival.