Assessment of sediment quality and pore water ecotoxicity in Kebir Rhumel basin (NE-Algeria): a combined approach

The objectives of this study are to use different approaches to assess the current pollution status in the wadis of the Kebir Rhumel basin. First, sediment trace metal contents were measured by flame atomic absorption spectroscopy. Then, sediment quality was assessed on the basis of contamination assessment indexes such as: Geoaccumulation Index (Igeo), Contamination factor (C(f)), Contamination degree (C(d)), Sediment Pollution Index (SPI) and SEQ guidelines (Consensus Sediment Quality Guidelines). In addition, several toxicity tests (Daphnia magna mobility inhibition acute test-48 h, Aliivibrio fischeri luminescence inhibition acute test - 15/30 mn and Pseudokirchneriella subcapitata growth inhibition chronic test - 72 h) were conducted to assess sediment pore water ecotoxicity. Trace metal concentrations followed the order: Mn > Zn > Pb > Cr > Cu > Ni > Co > Cd. Indexes used indicate varying degrees of sediment quality. Igeo, C(f), C(d) and SPI reveal a polymetallic contamination dominated by two or more elements in which Cd, Cu and Pb are of greatest concern. SEQ guidelines showed that biological effects on fauna would likely be observed occasionally and/or frequently for Cd, Cr, Cu, Pb and Zn contents. Test organisms exposed to sediment pore water showed that the algal P. subcapitata test was more sensitive than the D. magna and A. fischeri tests. Hence, algal growth inhibition proved to be the most sensitive response to contaminants present in sediment extracts but a significant relationship with trace metal contents was not demonstrated.     

GPU Shape Grammars

GPU Shape Grammars provide a solution for interactive procedural generation, tuning and visualization of massive environment elements for both video games and production rendering. Our technique generates detailed models without explicit geometry storage. To this end we reformulate the grammar expansion for generation of detailed models at the tesselation control and geometry shader stages. Using the geometry generation capabilities of modern graphics hardware, our technique generated massive, highly detailed models. GPU Shape Grammars integrate within a scalable framework by introducing automatic generation of levels of detail at reduced cost. We apply our solution for interactive generation and rendering of scenes containing thousands of buildings and trees.     

The Morning After: Limit Violations and the Self-Regulation of Alcohol Consumption.

The authors examined whether the reciprocal relationship between alcohol consumption and distress unfolded over time in 2 samples of social drinkers. Participants monitored their alcohol intake and their cognitive and emotional responses to that drinking on hand-held computers. On mornings after drinking, those who had violated their self-imposed limits the day before reported more guilt, even after controlling for acute negative symptoms of drinking and amount consumed. Reciprocally, guilt led to poorer self-regulation of alcohol intake: Greater distress over alcohol consumption was linked to more intake, intoxication, and more limit violations. Individual differences moderated the relationships among limit violations, distress, and drinking. Consistent with the limit violation effect, violating a limit produced distress over consumption among social drinkers, and they responded to that distress by drinking more. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Infidelity in Couples Seeking Marital Therapy.

The revelation of an affair is often an emotionally explosive event for a couple, yet little is known about specific individual and relationship factors that accompany infidelity. The present study examined the qualities of individuals and couples that differentiate couples with (n = 19) and without (n = 115) infidelity using couples from a randomized clinical trial of marital therapy. Findings indicated that couples with infidelity showed greater marital instability, dishonesty, arguments about trust, narcissism, and time spent apart. Gender also proved to be a significant moderator of several effects. Men who had participated in affairs showed increased substance use, were older, and were more sexually dissatisfied. Results offer initial clues to concomitants of affairs for couple therapists. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

10th GAMM-IMACS International Symposium on Scientific Computing,Computer Arithmetic,and Validated Numerics SCAN'2002

Reliable Computing -     

Simulator-mediated acquisition of a dynamic control skill

Uses of stored skill-models to accelerate simulator-based real-time training in a control skill are discussed. A real-time coach must deliver advice at three levels: (1) what to do next, (2) what to watch for, and (3) what went wrong. Human learning and machine learning results are presented using different screen representations of a pole-and-cart balancing task.     

Extracting Hidden Context

Concept drift due to hidden changes in context complicates learning in many domains including financial prediction, medical diagnosis, and communication network performance. Existing machine learning approaches to this problem use an incremental learning, on-line paradigm. Batch, off-line learners tend to be ineffective in domains with hidden changes in context as they assume that the training set is homogeneous. An off-line, meta-learning approach for the identification of hidden context is presented. The new approach uses an existing batch learner and the process of contextual clustering to identify stable hidden contexts and the associated context specific, locally stable concepts. The approach is broadly applicable to the extraction of context reflected in time and spatial attributes. Several algorithms for the approach are presented and evaluated. A successful application of the approach to a complex flight simulator control task is also presented.     

A comparative study of some concurrency control algorithms for cluster-based communication networks

This paper presents a comparative study of some concurrency control algorithms for distributed databases of computer clusters which emphasize high availability and high performance requirements. For this purpose, we have analyzed some concurrency control algorithms which are used in commercial DBMSs, such as the pessimistic locking algorithm as it verifies transaction conflicts early in their execution phase, and the optimistic algorithm which investigates the presence of conflicts after the execution phase. A new algorithm is proposed and implemented by a simulation program. The three algorithms were tested using different configurations. Simulation results showed that the locking algorithm performed better than the optimistic method in presence of conflicts between transactions, while the optimistic algorithm provided better results in the absence of conflicts. Furthermore, in a distributed database with a certain probability of conflicts, the locking algorithm can be used to guarantee strong consistency and an acceptable level of performance. However, if this probability is negligible, the system performance can be improved by using the optimistic algorithm. The proposed algorithm offers improved performance in numerous cases. As a result, it can be used in a distributed database to guarantee a satisfactory level of performance in the presence of conflicts.     

Editorial

International Journal of Computer Vision -