Patterning of worm-like soft polydimethylsiloxane structures using a TiO2 nanotubular array

Patterned polydimethylsiloxane (PDMS) is an important structure for soft lithography. Various materials have been deployed as mold for patterning PDMS. Anodized nanotubular array has been sought after as cost-effective alternative for textured silicon. An array of TiO₂ nanotubes with characteristic diameter ≈140 nm and the length of ≈1.5 microns, created by anodic oxidation of a titanium substrate, was used here as a template for soft PDMS molding. The optimal molding process was developed by a combination of silanization, use of solvent, application of a vacuum, and hydraulic pressing. The silanization was confirmed by Fourier transform infrared spectroscopy and contact angle measurements while the PDMS structure was examined by scanning electron microscope and energy dispersive X-ray spectroscopy. Hydraulic pressing significantly improved the infiltration of PDMS into the pores of nanotubular array resulting in formation of PDMS nanobumps after separation of the polymer from the template. Complete infiltration of PDMS precursor into the cavity of nanotubes was observed on the hydraulic-pressed sample without toluene impurities. The hydraulic-pressed samples exhibited higher adhesion strength than nonpressed ones. The adhesive strength was measured by a simple experimental arrangement, in which the PDMS layer was stuck on a vertical glass surface followed by pulling it downwards.     

Electrochemical Corrosion Behaviour of 90—10 Cu—Ni Alloy in Chloride-Based Electrolytes

The corrosion of 90–10 copper—nickel alloy in aqueous chloride electrolytes has received considerable attention in the literature due to its widespread use in seawater and saline environments. From an analysis of the electrochemical behaviour of the alloy, it is clear that both the polarization and mixed/corrosion potential characteristics show a close comparison to unalloyed copper. Important differences arise, however, due to the semi—conducting nature, composition and overall protectiveness of the corrosion products on the 90–10 copper—nickel alloy. In this work the metallurgy, electrochemistry and mechanism of passivation of the alloy are reviewed to provide a focused source of data regarding the electrochemical characteristics of the alloy in saline media.     

Collaboration Structure, Communication Media, and Problems in Scientific Work Teams

This article reviews the structural characteristics of work organizations that are likely to increase collaboration problems and tests the relationships between collaboration structure and problems using data from a survey of scientists in four fields (experimental biology, mathematics, physics, and sociology). Two groups of problems are identified: problems of coordination and misunderstandings and problems of cultural differences and information security. Greater coordination problems are associated with size, distance, interdependence, and scientific competition. Problems of culture and security are associated with size, distance, scientific competition, and commercialization. Email use is associated with reporting fewer coordination problems, but not fewer problems of culture and security, while neither phone use nor face-to-face meetings significantly reduces problems. We conclude with a discussion of the implications of these findings for designers of collaboration technologies and researchers involved in scientific collaborations.     

Is computational complexity a barrier to manipulation?

When agents are acting together, they may need a simple mechanism to decide on joint actions. One possibility is to have the agents express their preferences in the form of a ballot and use a voting rule to decide the winning action(s). Unfortunately, agents may try to manipulate such an election by mis-reporting their preferences. Fortunately, it has been shown that it is NP-hard to compute how to manipulate a number of different voting rules. However, NP-hardness only bounds the worst-case complexity. In this survey article, we summarize the evidence for and against computational complexity being a barrier to manipulation. We look both at techniques identified to increase complexity (for example, hybridizing together two or more voting rules), as well as other features that may change the computational complexity of computing a manipulation (for example, if votes are restricted to be single peaked then some of the complexity barriers fall away). We discuss recent theoretical results that consider the average case, as well as simple greedy and approximate methods. We also describe how computational ??phase transitions??, which have been fruitful in identifying hard instances of propositional satisfiability and other NP-hard problems, have provided insight into the hardness of manipulating voting rules in practice. Finally, we consider manipulation of other related problems like stable marriage and tournament problems.     

QuickBird and Hyperion data analysis of an invasive plant species in the Galapagos Islands of Ecuador: Implications for control and land use management

In the Galapagos Islands of Ecuador, one of the greatest threats to the terrestrial ecosystem is the increasing number and areal extent of invasive species. Increased human presence on the islands has hastened the introduction of plant and animal species that threaten the native and endemic flora and fauna. Considerable research on invasive species in the Galapagos Islands has been conducted by the Charles Darwin Foundation. We complement that work through a spatially- and spectrally-explicit satellite assessment of an important invasive plant species (Psidium guajava — guava) on Isabela Island that integrates diverse remote sensing systems, data types, spatial and spectral resolutions, and analytical and image processing approaches. QuickBird and Hyperion satellite data are processed to characterize the areal extent and spatial structure of guava through the following approaches: (1) QuickBird data are classified through a traditional pixel-based approach (i.e., an unsupervised classification approach using the ISODATA algorithm), as well as an Object-Based Image Analysis (OBIA) approach; (2) multiple approaches for spectral “unmixing” of the Hyperion hyper-spectral data are assessed to construct spectral end-members from QuickBird data using linear and non-linear mixture modeling approaches; and (3) landscape pattern metrics are calculated and compared for the pixel-based, object-based, and spectral unmixing approaches. The spectral–spatial characteristics of guava are interpreted relative to management strategies for the control of guava and the restoration of natural ecosystems in the Galapagos National Park.     

Production Equations for Unsteady-State Construction Processes

The production equation called Little’s law has been applied to construction data recently. However, Little’s law was derived for steady-state conditions assuming constant input and output rates and long production runs. Production in construction is inherently temporary, and learning curves and environmental influences often render input and output rates unequal and nonlinear. Starting with a conservation of mass formulation, general equations for work-in-process and cycle time for unsteady-state conditions and limited run production are developed. The motivation behind these equations is to explain common trends in production variables seen on construction projects. Previous studies have shown that when output from a construction production system is drastically increased, a significant upward impact is also seen on cycle time and work-in-process, and this work provides underlying theory and equations to explain these trends. Cycle time and work-in-process equations are presented as functions of time and on average. Data from construction activities are used to show that unsteady-state conditions commonly occur. Reasonable simplifications of the general equations provide guidelines for buffer sizing and resource allocation decisions.     

The effect of nicotine and attention allocation on physiological and self-report measures of induced anxiety in PTSD: A double-blind placebo-controlled trial.

Rates of smoking among populations with psychiatric disorders are more than twice as high as among the general population, yet there are few controlled studies of the mechanisms of this relationship. This trial examined the effect of nicotine by way of cigarette smoking on both self-report and autonomic parameters of anxiety among individuals with PTSD who were also heavy smokers. Half of the participants were randomized to an anxiety-eliciting condition, whereas the other half were assigned to a condition of neutral emotional content. Within each of these conditions, participants were randomized into a nicotine condition (high-yield nicotine cigarette) or a placebo condition (denicotinized cigarette). The final layer of randomization involved assigning participants to either an attention-demanding task or a no task condition. We examined the interactive effects of nicotine and attentional demand on parameters of anxious responding. Nicotine exerted an anxiolytic effect relative to placebo on self-report measures; however, nicotine did not interact with attentional demand in producing this effect. In contrast to the findings on the self-report measures of distress, nicotine enhanced autonomic reactivity to trauma cues, thereby suggesting a decoupling of self-reported anxiety and autonomic arousal associated with responding to trauma-relevant cues. The implications for understanding smoking and psychiatric comorbidity are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Water,image, gesture and sound: composing and performing an interactive audiovisual work

Performing and composing for interactive audiovisual system presents many challenges to the performer. Working with visual, sonic and gestural components requires new skills and new ways of thinking about performance. However, there are few studies that focus on performer experience with interactive systems. We present the work Blue Space for oboe and interactive audiovisual system, highlighting the evolving process of the collaborative development of the work. We consider how musical and technical demands interact in this process, and outline the challenges of performing with interactive systems. Using the development of Blue Space as a self-reflective case study, we examine the role of gestures in interactive audiovisual works and identify new modes of performance.     

WISC-R factor score profiles and academic achievement: A test of Kaufman's profile analysis procedures.

A. S. Kaufman (1979) suggested that factor score patterns may yield information about achievement that is additional to information contained in WISC-R composite scores. The present study examined the relation between factor score patterns and achievement beyond the well-established relationship between WISC-R composite scores and achievement. The WISC-R, including the Digit Span subtest, and the Reading, Spelling, and Arithmetic subtests of the Wide Range Achievement Test (WRAT) were administered to 272 6–16 yr old academic underachievers referred for psychoeducational assessment. Results of the examination of factor score patterns and WRAT achievement scores indicate that 2 of the 10 patterns present in the data had a statistically significant relationship to achievement. While both patterns were negatively associated with achievement, the size of their contribution to achievement variance was small and in the order of 2%. These results impose limits on the utility of Kaufman's profile analysis procedures. (French abstract) (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Graduate school origins of Journal of Counseling Psychology authors: Volumes 15-28.

Examined the graduate school origins of authors of Journal of Counseling Psychology (JCP) articles in Volumes 15–28 to extend a previous analysis of Volumes 1–24 by the 3rd author et al (1969). Comparisons of the 2 14-yr periods reveal that some universities retained the same or similar ranks across both periods, some declined in importance as sources of authors, and others emerged as major sources of JCP authors. (6 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)