Peirce algebras

We present a two-sorted algebra, called aPeirce algebra, of relations and sets interacting with each other. In a Peirce algebra, sets can combine with each other as in a Boolean algebra, relations can combine with each other as in a relation algebra, and in addition we have both a set-forming operator on relations (the Peirce product of Boolean modules) and a relation-forming operator on sets (a cylindrification operation). Two applications of Peirce algebras are given. The first points out that Peirce algebras provide a natural algebraic framework for modelling certain programming constructs. The second shows that the so-calledterminological logics arising in knowledge representation have evolved a semantics best described as a calculus of relations interacting with sets.     

The High Field Project at Dresden/Rossendorf: A Pulsed 100 T/10 ms Laboratory at an Infrared Free-Electron-Laser Facility

This article describes the project to build a pulsed magnetic field user laboratory at the Forschungszentrum Rossendorf near Dresden. Using a 50 MJ/24 kV capacitor bank, pulsed fields and rise times of 100 T/10 ms, 70 T/100 ms, and 60 T/1 s should be achieved. The laboratory will be built next to a free-electron-laser-facility for the middle and far infrared (5 to 150 µm, 2 ps, cw). We describe the work which has been performed until now to start the construction of the laboratory in 2003: coil concepts and computer simulations, materials development for the high field coils, and design of the capacitor bank modules. In addition, a pilot laboratory has been set up where fields up to 62 T/15 ms have been obtained with a 1 MJ/10 kV capacitor module. It is used to gain experience in the operation of such a facility and to test various parts of it. In this test laboratory special devices have been developed for measurements of magnetization and magnetoresistance, and have been successfully used to investigate various materials including semiconductors and Heavy Fermion compounds. In particular, metamagnetic transitions in intermetallic compounds and the irreversibility field of a high-T _c superconductor have been determined. Shubnikov–de Haas oscillations have been observed in the semimetallic compound CeBiPt. Resistance relaxation has been observed to start less than 1second after the field pulse. It could be shown for the first time that nuclear magnetic resonance (NMR) is detectable in pulsed fields.     

Review of Counseling and psychotherapy of work dysfunctions.

Reviews the book, Counseling and psychotherapy of work dysfunctions by Rodney L. Lowman (see record 1993-98413-000). Dr. Lowman's book on work dysfunctions serves as a seminal product for further understanding a much-neglected component of the lives of the many men and women who seek psychological assistance in working through issues around their employment. The book conveys in a well-written, sometimes humorous, style that "work is a natural part of living, and the issues it raises are important parts of character." The overall impression is that of a well-thought-out and most readable book. There is no doubt in this reviewer's mind that it will become essential reading for psychologists, social workers, family therapists, and graduate students who are becoming increasingly involved in this field of study. What this reviewer found very helpful was the clarity of presentation of the assessment techniques as well as the amply illustrated intervention modules that may be utilized. To this reviewer, there is no doubt that this is one area for psychologists' contributions in the future--the work area. Lowman's book gives us basic material from which to continue to build our profession in a new and exciting direction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Proline versus charge concept for protein stabilization against proteolytic attack

The virtue of the so-called ‘proline concept’ andthe ‘charge concept’ for stabilizing protease-susceptibleregions of a protein structure was compared on bovine pancreaticribonuclease A. Alanine 20 and serine 21, both of whichare located in a loop that is susceptible to the unspecificproteases subtilisin Carlsberg, subtilisin BPN', proteinaseK and elastase, were replaced with proline or lysine by site-directedmutagenesis. The rate constant of proteolysis was decreasedby up to three orders of magnitude for the proline mutants dependingon the site of the mutation and the protease used. In contrast,substitution by lysine increased the proteolytic resistanceby only one order of magnitude characterizing the ‘prolineconcept’ as superior to the ‘charge concept’.Although the four applied proteases are considered to be unspecific,the degree of stabilization of the ribonuclease molecule variedconsiderably, indicating the impact of individual differencesin their substrate specificity on the proteolytic resistanceand degradation pathway of the target protein. Received May 12, 2003; revised October 23, 2003; accepted October 30, 2003     

The WALL: participatory design workspace in support of creativity, collaboration, and socialization

A key challenge faced by organizations is to provide project teams with workspaces, information, and collaboration technologies that fosters creativity and high-performance team productivity. This requires understanding the relation between and impacts of (1) workspace, (2) activity and content that is created, and (3) social, behavioral, and cognitive aspects of work. This paper describes an exploratory study of everyday activities in the context of knowledge work in a shared workspace used by a high-tech global design team that explores future products. The study formalizes key elements for productive knowledge work as a function of tasks, context, and team. It identifies enablers, hindrances, and requirements for physical, virtual, and social work environments. The study identified, through semi-structured interviews, surveys, and on-site shadowing, a key workspace component that facilitates dynamic participation of all team members. This workspace component is a wall used as a large, public, physical display surface for project content (the WALL). The WALL acts as a mediator for individual reflection-in-action and team reflection-in-interaction. It serves as “social glue” both between individuals and between geographically distributed subgroups.     

Building common ground in global teamwork through re-representation

We explore in this paper the relation between activities, communication channels and media, and common ground building in global teams. We define re-representation as a sequence of representations of the same concept using different communication channels and media. We identified the re-representation technique to build common ground that is used by team members during multimodal and multimedia communicative events in cross-disciplinary, geographically distributed settings. Our hypotheses are as follows: (1) Significant sources of information behind decisions and request for actions are embedded within the fabric of communicative events in which participants use both informal and formal media to express their ideas. Capturing these information sources can facilitate common ground building and accelerate the execution of action requests. (2) Re-representations of concepts, i.e., sequences of representations using diverse media and communication channels, mediate and accelerate common ground building. (3) The use of intra- or interdisciplinary re-representations correlates with high team performance, i.e., effective team process and high product quality. We used AEC Global Teamwork course offered in 2008–2009 as the testbed for our study to validate our hypothesis.     

Multi-Agent Dynamic Logics with Informational Test

This paper investigates a family of logics for reasoning about the dynamic activities and informational attitudes of agents, namely the agents' beliefs and knowledge. The logics are based on a new formalisation and semantics of the test operator of propositional dynamic logic and a representation of actions which distinguishes abstract actions from concrete actions. The new test operator, called informational test, can be used to formalise the beliefs and knowledge of particular agents as dynamic modalities. This approach is consistent with the formalisation of the agents' beliefs and knowledge as K(D)45 and S5 modalities. Properties concerning informativeness, truthfulness and preservation of beliefs are proved for a derivative of the informational test operator. It is shown that common belief and common knowledge can be expressed in the considered logics. This means, the logics are more expressive than propositional dynamic logic with an extra modality for belief or knowledge. The logics remain decidable and belong to 2EXPTIME. Versions of the considered logics express natural additional properties of beliefs or knowledge and interaction of beliefs or knowledge with actions. It is shown that a simulation of PDL can be constructed in one of these extensions.     

Oxide scale formation of modified FeCrAl coatings exposed to liquid lead

Modified FeCrAl coatings were studied with respect to their capability to form a thin protective oxide scale in liquid lead environment. They were manufactured by low pressure plasma spraying and GESA surface melting, thereby tuning the Al content. The specimens were exposed for 900 h to liquid lead containing 10^?6 and 10^?8 wt.% oxygen, respectively, at various temperatures from 400 to 550 °C. Threshold values for an Al content that guarantees the formation of thin protective Al-rich oxide scales are determined, dependent on the respective chromium content, on the presence of yttrium in the modified coating, and on the exposure conditions.     

Occurrence of perfluoroalkyl compounds in surface waters from the North Pacific to the Arctic Ocean

Perfluoroalkyl compounds (PFCs) were determined in 22 surface water samples (39-76°N) and three sea ice core and snow samples (77-87°N) collected from North Pacific to the Arctic Ocean during the fourth Chinese Arctic Expedition in 2010. Geographically, the average concentration of ∑PFC in surface water samples were 560 ± 170 pg L(-1) for the Northwest Pacific Ocean, 500 ± 170 pg L(-1) for the Arctic Ocean, and 340 ± 130 pg L(-1) for the Bering Sea, respectively. The perfluoroalkyl carboxylates (PFCAs) were the dominant PFC class in the water samples, however, the spatial pattern of PFCs varied. The C(5), C(7) and C(8) PFCAs (i.e., perfluoropentanoate (PFPA), perfluoroheptanoate (PFHpA), and perfluorooctanoate (PFOA)) were the dominant PFCs in the Northwest Pacific Ocean while in the Bering Sea the PFPA dominated. The changing in the pattern and concentrations in Pacific Ocean indicate that the PFCs in surface water were influenced by sources from the East-Asian (such as Japan and China) and North American coast, and dilution effect during their transport to the Arctic. The presence of PFCs in the snow and ice core samples indicates an atmospheric deposition of PFCs in the Arctic. The elevated PFC concentration in the Arctic Ocean shows that the ice melting had an impact on the PFC levels and distribution. In addition, the C(4) and C(5) PFCAs (i.e., perfluorobutanoate (PFBA), PFPA) became the dominant PFCs in the Arctic Ocean indicating that PFBA is a marker for sea ice melting as the source of exposure.