Exposure assessment to preformed environmental N-nitroso compounds from the point of view of our own studies

The largest human exposure to N-nitrosamines is in the industrial section. Leather tanners are exposed to N-nitrosodimethylamine at levels up to 47 microgram/m3, corresponding to 440 microgram/person/day. Workers in the curing area of tire factories are exposed to N-nitrosomorpholine at levels up to 27 microgram/m3, corresponding to a intake of 250 microgram/person/day. These industrial exposures are considerably greater than exposure via foodstuffs, beer, cosmetics, cutting fluids and herbicides.     

Mechanical proof testing

A computer program has been written in PL/I to check the correctness of proofs in an axiomatic theory. A notation for the statements of the theory is described. Application examples are provided.     

Soft X‐ray Ptychographic Imaging and Morphological Quantification of Calcium Silicate Hydrates (C–S–H)

Morphological details of calcium silicate hydrate (C–S–H) stemming from the hydration process of Portland cement (PC) phases are crucial for understanding the PC‐based systems but are still only partially known. Here we introduce the first soft X‐ray ptychographic imaging of tricalcium silicate (C₃S) hydration products. The results are compared using both scanning transmission X‐ray and electron transmission microscopy data. The evidence shows that ptychography is a powerful method to visualize the details of outer and inner product C–S–H of fully hydrated C₃S, which have fibrillar and an interglobular structure with average void sizes of 20 nm, respectively. The high‐resolution ptychrography image enables us to perform morphological quantification of C–S–H, and, for the first time, to possibly distinguish the contributions of inner and outer product C–S–H to the small angle scattering of cement paste. The results indicate that the outer product C–S–H is mainly responsible for the q^?3 regime, whereas the inner product C–S–H transitions to a q^?2 regime. Various hypotheses are discussed to explain these regimes.     

A comparative empirical study on social media sentiment analysis over various genres and languages

People express their opinions about things like products, celebrities and services using social media channels. The analysis of these textual contents for sentiments is a gold mine for marketing experts as well as for research in humanities, thus automatic sentiment analysis is a popular area of applied artificial intelligence. The chief objective of this paper is to investigate automatic sentiment analysis on social media contents over various text sources and languages. The comparative findings of the investigation may give useful insights to artificial intelligence researchers who develop sentiment analyzers for a new textual source. To achieve this, we describe supervised machine learning based systems which perform sentiment analysis and we comparatively evaluate them on seven publicly available English and Hungarian databases, which contain text documents taken from Twitter and product review sites. We discuss the differences among these text genres and languages in terms of document- and target-level sentiment analysis.     

Performance evaluation of Web proxy cache replacement policies

The continued growth of the World-Wide Web and the emergence of new end-user technologies such as cable modems necessitate the use of proxy caches to reduce latency, network traffic and Web server loads. In this paper we analyze the importance of different Web proxy workload characteristics in making good cache replacement decisions. We evaluate workload characteristics such as object size, recency of reference, frequency of reference, and turnover in the active set of objects. Trace-driven simulation is used to evaluate the effectiveness of various replacement policies for Web proxy caches. The extended duration of the trace (117 million requests collected over 5 months) allows long term side effects of replacement policies to be identified and quantified.

Our results indicate that higher cache hit rates are achieved using size-based replacement policies. These policies store a large number of small objects in the cache, thus increasing the probability of an object being in the cache when requested. To achieve higher byte hit rates a few larger files must be retained in the cache. We found frequency-based policies to work best for this metric, as they keep the most popular files, regardless of size, in the cache. With either approach it is important that inactive objects be removed from the cache to prevent performance degradation due to pollution.     

Lessons learned from programmers' experiences with one‐way constraints

One‐way constraints have been incorporated in many graphical user interface toolkits because they are simple to learn, easy to write, and can express many types of useful graphical relationships. This paper is an evaluative paper that examines users' experience with one‐way constraints in two user interface development toolkits, Garnet and Amulet, over a 15‐year time span. The lessons gained from this examination can help guide the design of future constraint systems. The most important lessons are that (1) constraints should be allowed to contain arbitrary code that is written in the underlying toolkit language and does not require any annotations, such as parameter declarations, (2) constraints are difficult to debug and better debugging tools are needed, and (3) programmers will readily use one‐way constraints to specify the graphical layout of an application, but must be carefully and time‐consumingly trained to use them for other purposes. Copyright © 2005 John Wiley & Sons, Ltd.     

Self-efficacy and work-related performance: The integral role of individual differences.

The present study estimated the unique contribution of self-efficacy to work-related performance controlling for personality (the Big 5 traits), intelligence or general mental ability, and job or task experience. Results, based on a meta-analysis of the relevant literatures, revealed that overall, across all studies and moderator conditions, the contribution of self-efficacy relative to purportedly more distal variables is relatively small. Within moderator categories, there were several cases in which self-efficacy made unique contributions to work-related performance. For example, self-efficacy predicted performance in jobs or tasks of low complexity but not those of medium or high complexity, and self-efficacy predicted performance for task but not job performance. Overall, results suggest that the predictive validity of self-efficacy is attenuated in the presence of individual differences, though this attenuation does depend on the context. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Indefinite integration as term rewriting: Integrals containing tangent

We describe the development of a term-rewriting system for indefinite integration; it is also called a rule-based evaluation system. The development is separated into modules, and we describe the module for a wide class of integrands containing the tangent function.