The influence of current density on the electrochemical properties of anion-exchange membranes in electrodialysis of phenylalanine solution

Electrochemical properties of heterogeneous anion-exchange membranes can be indicators of their fouling during electrodialysis of phenylalanine solutions. The current–voltage curves of the membrane MA-40 make it possible to reveal the difference in the limiting current values for fresh and fouled membranes. Increase of membrane voltage with time characterizes the development of fouling in the electromembrane system. Membrane conductivity decreases significantly in solutions containing phenylalanine. Overlimiting current conditions lead to “washing out” of amino acid from membrane phase and therefore help to avoid fouling.     

The craving to smoke in flight attendants: Relations with smoking deprivation, anticipation of smoking, and actual smoking.

In the study, the authors examined the effects of smoking deprivation, anticipation of smoking, and actual smoking on the craving to smoke. Flight attendants who were light to heavy smokers rated their craving to smoke at predetermined time points during a 2-way short flight (each leg 3–5.5 hr) and a 1-way long flight (8–13 hr). In both short and long flights, craving increased gradually and peaked as landing approached. Craving levels at the end of the 1st leg of the short flights were equal to those at the end of the long flight and were much higher than those at the parallel time point in the long flight. In the short flight, craving levels at the beginning of the 2nd leg dropped relative to the end of the 1st leg, both for participants who smoked during the intermission and for those who did not, though the drop was steeper for the former. The results provide additional evidence for the role of psychological factors in determining the craving to smoke in a naturalistic setting. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mechanisms of size control and polymorphism in viral capsid assembly

We simulate the assembly dynamics of icosahedral capsids from subunits that interconvert between different conformations (or quasi-equivalent states). The simulations identify mechanisms by which subunits form empty capsids with only one morphology but adaptively assemble into different icosahedral morphologies around nanoparticle cargoes with varying sizes, as seen in recent experiments with brome mosaic virus (BMV) capsid proteins. Adaptive cargo encapsidation requires moderate cargo-subunit interaction strengths; stronger interactions frustrate assembly by stabilizing intermediates with incommensurate curvature. We compare simulation results to experiments with cowpea chlorotic mottle virus empty capsids and BMV capsids assembled on functionalized nanoparticles and suggest new cargo encapsidation experiments. Finally, we find that both empty and templated capsids maintain the precise spatial ordering of subunit conformations seen in the crystal structure even if interactions that preserve this arrangement are favored by as little as the thermal energy, consistent with experimental observations that different subunit conformations are highly similar.     

Adjustable spiral phase plate

A spiral phase retarder phi(r, theta) = mtheta has been constructed with use of a deformed cracked plexiglass plate. By changing the degree of deformation, the retarder can be adjusted for use at any wavelength, and the value of the phase step 2pim at theta = 2pi can be chosen.     

An Exploratory Look at Students' Experiences of Problematic Peers in Academic Professional Psychology Programs.

This exploratory survey investigated the issue of problematic students/trainees from the perspective of master's and doctoral students in clinical and counseling psychology programs. Findings suggest that students (a) were aware of problematic trainees in their programs; (b) believed faculty were primarily responsible for handling problematic peers, though students were unclear about procedures for handling this issue; (c) expressed greatest concerns about issues involving peers' interpersonal functioning; and (d) responded by gossiping or consulting with other peers, withdrawing, and, less often, confronting a problem peer. Problematic peers impacted respondents' own functioning, relationships with peers, and perceptions of faculty, and they disrupted the learning environment. Study implications and limitations are noted. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Near-field effects in multilayer inductive metal meshes

The transmittance of inductive single-layer and multilayer cross-shaped metal meshes has been calculated with the Micro-Stripes software program. The effect of symmetric and asymmetric alignment of the crosses of one mesh with respect to another was studied and compared with transmission line theory, which presents the nonaligned case. Significant differences are found for small spacing at approximately 1/5 the periodicity constant, whereas the differences disappear for large spacing. A pair of coupled surface waves is used to represent the mode of a single mesh. The resulting modes corresponding to the transmittance of multilayer metal meshes are interpreted by modes composed of resonance modes of a single mesh coupled by Fabry-Perot modes depending on the separation.     

Analysis of a probabilistic model of redundancy in unsupervised information extraction

Unsupervised Information Extraction (UIE) is the task of extracting knowledge from text without the use of hand-labeled training examples. Because UIE systems do not require human intervention, they can recursively discover new relations, attributes, and instances in a scalable manner. When applied to massive corpora such as the Web, UIE systems present an approach to a primary challenge in artificial intelligence: the automatic accumulation of massive bodies of knowledge.A fundamental problem for a UIE system is assessing the probability that its extracted information is correct. In massive corpora such as the Web, the same extraction is found repeatedly in different documents. How does this redundancy impact the probability of correctness?We present a combinatorial “balls-and-urns” model, called Urns, that computes the impact of sample size, redundancy, and corroboration from multiple distinct extraction rules on the probability that an extraction is correct. We describe methods for estimating Urns's parameters in practice and demonstrate experimentally that for UIE the model's log likelihoods are 15 times better, on average, than those obtained by methods used in previous work. We illustrate the generality of the redundancy model by detailing multiple applications beyond UIE in which Urns has been effective. We also provide a theoretical foundation for Urns's performance, including a theorem showing that PAC Learnability in Urns is guaranteed without hand-labeled data, under certain assumptions.     

Unsupervised named-entity extraction from the Web: An experimental study

The KnowItAll system aims to automate the tedious process of extracting large collections of facts (e.g., names of scientists or politicians) from the Web in an unsupervised, domain-independent, and scalable manner. The paper presents an overview of KnowItAll's novel architecture and design principles, emphasizing its distinctive ability to extract information without any hand-labeled training examples. In its first major run, KnowItAll extracted over 50,000 class instances, but suggested a challenge: How can we improve KnowItAll's recall and extraction rate without sacrificing precision?This paper presents three distinct ways to address this challenge and evaluates their performance. Pattern Learning learns domain-specific extraction rules, which enable additional extractions. Subclass Extraction automatically identifies sub-classes in order to boost recall (e.g., “chemist” and “biologist” are identified as sub-classes of “scientist”). List Extraction locates lists of class instances, learns a “wrapper” for each list, and extracts elements of each list. Since each method bootstraps from KnowItAll's domain-independent methods, the methods also obviate hand-labeled training examples. The paper reports on experiments, focused on building lists of named entities, that measure the relative efficacy of each method and demonstrate their synergy. In concert, our methods gave KnowItAll a 4-fold to 8-fold increase in recall at precision of 0.90, and discovered over 10,000 cities missing from the Tipster Gazetteer.     

Delivering services by building and running virtual organisations

Customers in the future are likely to obtain their services from coalitions of service providers. These coalitions can be described as virtual organisations (VOs); they are groups of service providers that form relationships to service customers’ demands on an ad-hoc basis. For a VO to be effective, it must be reliable and scalable, and, realistically, it must be created and maintained in a dynamic, open and competitive environment. The CONOISE-G project has focused on resolving the technology challenges that emerged from these requirements. Specifically, CONOISE-G provides mechanisms to assure effective operation of VOs in the face of failure, unexpected events and changing requirements in a dynamic, open and competitive environment. In this paper, we describe the CONOISE-G system, motivated by a scenario based on mobile service provision, outline its use in the context of VO formation and perturbation, and review current efforts to progress the work to deal with unreliable information sources.