Crosslinked poly(vinyl alcohol) hydrogels as swollen elastic networks

Transparent crosslinked PVA hydrogels were prepared by electron beam irradiation of aqueous solutions under nitrogen. These weak hydrogels, upon swelling at 30°C in water, showed low elastic moduli (up to 50 psi), low ultimate tensile strength (up to 4 psi), and low extensibility to break (not higher than 85%). Values of the molecular weight between crosslinks M_c were calculated from swelling and from tensile experiments. In fact, two values of M_c were calculated for each swelling experiment, (a) allowing for observed variation in the polymer–solvent interaction parameter χ₁ with concentration, and (b) fixing χ₁ = 0.494 according to literature data. The correlation of the M_c obtained from tensile data with the M_c obtained from swelling data, by (a) or (b), was approximately linear and gave the same per cent agreement.     

A National Survey of Practicing Psychologists' Use and Attitudes Toward Homework in Psychotherapy.

Homework assignments have been studied extensively in psychotherapy research, but there is little data on the way in which homework is transferred to clinical practice. A survey was conducted of 827 practicing psychologists nationwide regarding their use and attitudes toward homework. Overall, 68% of the present sample indicated that they "often" or "almost always" used homework assignments. Factor analysis revealed that practitioners have a range of attitudes that can be classified as reflecting the notion that homework has (a) a negative impact on in-session therapeutic work and (b) a positive effect on therapy outcomes. More positive attitudes were reported among those with a cognitive-behavioral theoretical orientation. Nevertheless, the use of homework among psychodynamic/analytic practitioners reported in the present sample was unexpected and suggests that theoretical and empirical work is required to examine homework's effects in a range of psychotherapy approaches. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Psychologists' Use of Motion Pictures in Clinical Practice.

Do professional psychologists use motion pictures in clinical practice? If so, do they consider motion pictures to have therapeutic value? Of 827 licensed practicing psychologists, 67% reported the use of motion pictures to promote therapy gains. Most of these practitioners (88%) considered the use of motion pictures as effective in promoting treatment outcome, and only a minority (1%) reported them as potentially harmful. Compared with their psychodynamic counterparts, therapists practicing within eclectic-integrative, cognitive-behavioral, or humanistic frameworks were more likely to view or use motion pictures as therapeutic tools. Psychologists provided individual evaluations of 27 motion pictures that deal with a variety of mental health subjects, and overall they were characterized as "moderately helpful." Clinical applications and issues pertaining to using motion pictures in therapy are summarized. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Heterogeneous system level co-simulation for the design of telecommunication systems

The advanced complexity and heterogeneity of modern telecommunication systems mostly lead to the incorporation of heterogeneous implementation technologies and design styles. Consequently, the design representation of such systems often requires the mixed use of distinct model of computations at different abstraction layers. Therefore, heterogeneous co-simulation is needed in order to enable the effective communication and interaction among the involved models of computation. This paper resolves this issue by proposing the heterogeneous co-modelling of telecom systems based on the combination of SDL semantics with C language running on an instruction set simulator, coupling in that way the specification and the first refinement steps of the co-design flow. The missing test link between the corresponding tools that support the SDL-C co-model is addressed by proposing a heterogeneous co-simulation scheme through the development of a mediator. Finally, the proposed methodology and the efficiency of the built environment are evaluated through a case study associated with the design of the MAC layer of the DECT telecom system.^1,2     

Origami Metamaterials for Tunable Thermal Expansion

Materials with engineered thermal expansion, capable of achieving targeted area/volume changes in response to variations in temperature, are important for a number of aerospace, optical, energy, and microelectronic applications. While most of the proposed structures with engineered coefficient of thermal expansion consist of bi‐material 2D or 3D lattices, here it is shown that origami metamaterials also provide a platform for the design of systems with a wide range of thermal expansion coefficients. Experiments and simulations are combined to demonstrate that by tuning the geometrical parameters of the origami structure and the arrangement of plates and creases, an extremely broad range of thermal expansion coefficients can be obtained. Differently from all previously reported systems, the proposed structure is tunable in situ and nonporous.     

Biomedical research productivity and economic crisis in Greece: a 22-year study

This article aims to study the effect of the current financial crisis (2010–2017) on biomedical productivity and impact of Greece-affiliated investigators. PubMed, Scopus and Web of Science were searched for articles published in biomedical journals with at least one Greek affiliation during the period 1995–2016 (date of last search October 19, 2017). The impact of Greek articles was the citations received by published articles during the first 2 years following the year of publication adjusted to the number of Greek and global articles. A discrepancy in the absolute article productivity between the databases was observed: a mean annual increase before the crisis was observed in all databases, while after the crisis the increase persisted in PubMed, in Scopus a decline was observed and in the Web of Science a smaller increase was observed. The changes in relative productivity were similar for both study periods in all databases (increasing before and decreasing after crisis, p?<?0.001 for trend in both periods). A continuous increase in total citations in both periods was observed (mean 2347?±?1622 before and 2627?±?3374 after the crisis). A continuous increase in the impact indices following adjustment for Greek (mean annual increase 0.27?±?0.30 before to 0.37?±?0.62 during the crisis, p?=?0.58) and global productivity (mean annual increase from 0.0024?±?0.0018 to 0.0007?±?0.004, p?=?0.95) was observed throughout the study period. In conclusion, the decline observed in the relative productivity of Greek affiliated articles during crisis compared to the period before was not reflected in their impact.     

Agglomeration Dynamics of 1D Materials: Gas‐Phase Collision Rates of Nanotubes and Nanorods

The agglomeration and self‐assembly of gas‐phase 1D materials in anthropogenic and natural systems dictate their resulting nanoscale morphology, multiscale hierarchy, and ultimate macroscale properties. Brownian motion induces collisions, upon which 1D materials often restructure to form bundles and can lead to aerogels. Herein, the first results of collision rates for 1D nanomaterials undergoing thermal transport are presented. The Langevin dynamic simulations of nanotube rotation and translation demonstrate that the collision kernels for rigid nanotubes or nanorods are ≈10 times greater than spherical systems. Resulting reduced order equations allow straightforward calculation of the physical parameters to determine the collision kernel for straight and curved 1D materials from 10² to 10⁶ nm length. The collision kernels of curved 1D structures increase ≈1.3 times for long (>10² nm), and ≈5 times for short (≈10² nm) relative to rigid materials. Applications of collision frequencies allow the first kinetic analysis of aerogel self‐assembly from gas‐phase carbon nanotubes (CNTs). The timescales for CNT collision and bundle formation (0.3–42 s) agree with empirical residence times in CNT reactors (3–15 s). These results provide insights into the CNT length, number, and timescales required for aerogel formation, which bolsters our understanding of mass‐produced 1D aerogel materials.     

Concurrent Delay Testing in Totally Self-Checking Systems

Prompt detection of even small delay faults, sometimes before causing critical paths to fail, gains importance since stricter test quality requirements for high performance and high density VLSI circuits have to be satisfied in critical applications. This can be achieved by using concurrent delay testing.In this paper a novel idea for concurrent detection of two-rail path delay faults is introduced. It is shown that TSC two-rail code error indicators that monitor pairs of paths with similar propagation delays can be used for concurrent delay testing. Our technique is applied to TSC two-rail code checkers as well as to duplication systems which are the most widely used TSC systems. The design of TSC two-rail code checkers and TSC duplication systems with respect to two-rail path delay faults is achieved for first time in the open literature.     

Human action annotation,modeling and analysis based on implicit user interaction

This paper proposes an integrated framework for analyzing human actions in video streams. Despite most current approaches that are just based on automatic spatiotemporal analysis of sequences, the proposed method introduces the implicit user-in-the-loop concept for dynamically mining semantics and annotating video streams. This work sets a new and ambitious goal: to recognize, model and properly use “average user’s” selections, preferences and perception, for dynamically extracting content semantics. The proposed approach is expected to add significant value to hundreds of billions of non-annotated or inadequately annotated video streams existing in the Web, file servers, databases etc. Furthermore expert annotators can gain important knowledge relevant to user preferences, selections, styles of searching and perception.     

A method for improving the accuracy of data mining classification algorithms

In this paper we introduce a method called CL.E.D.M. (CLassification through ELECTRE and Data Mining), that employs aspects of the methodological framework of the ELECTRE I outranking method, and aims at increasing the accuracy of existing data mining classification algorithms. In particular, the method chooses the best decision rules extracted from the training process of the data mining classification algorithms, and then it assigns the classes that correspond to these rules, to the objects that must be classified. Three well known data mining classification algorithms are tested in five different widely used databases to verify the robustness of the proposed method.