Attending to color with proper fixation

In contemporary theorizing, there is a controversy about the role of spatial location in the selection of visual information; some theories postulate that position plays a unique role, whereas other theories hold that position is just one selection dimension that is not different from other dimensions, such as color and shape. In this context, a paradigm introduced by Tsal and Lavie (1988) promised to be of fundamental importance. With that paradigm, Tsal and Lavie found that, after reporting a first letter of a prespecified color, subjects preferred to switch their reporting to letters from array positions adjacent to that letter over continuing to report letters of the same color as that of the first letter. This switch from color to position provided firm evidence in favor of the "position-special" views as opposed to the "all-attributes-are-equal" views. In the present study, six experiments, employing Tsal and Lavie's paradigm and variations of that paradigm, are reported. Experiments 1,2,4, and 5 show that evidence for a switch from selection on the basis of color to selection on the basis of position is not obtained when subjects are forced to fixate the fixation point and possibly also not under normal contrast conditions without fixation controls. Experiment 3 shows that switching from color to position is difficult. Experiments 2, 5, and 6 show that evidence for a switch is obtained only under low-contrast conditions when subjects are not forced to fixate the fixation point. It is concluded that the Tsal and Lavie paradigm is an asymmetric paradigm. The results reported by Tsal and Lavie constituted a major threat for the "all-attributes-are-equal" theories and provided firm support for the "position-special" theories. The results reported in the present study are compatible with the all-attributes-are-equal theories, but, at the same time, do not constitute a major threat for the contemporary position-special theories.     

Set-driven and rearrangement-independent learning of recursive languages

This paper studies the impact of order independence to the learnability of indexed families of uniformly recursive languages from positive data. In particular, we considerset-driven andrearrangement-independent learners, i.e., learning devices whose output exclusively depends on the range and on the range and length of their input, respectively. The impact of set-drivenness and rearrangement-independence on the behavior of learners to their learning power is studied in dependence on thehypothesis space the learners may use. We distinguish betweenexact learnability ( has to be inferred with respect to ),class-preserving learning ( has to be inferred with respect to some suitably chosen enumeration of all the languages from ), andclass-comprising inference ( has to be learned with respect to some suitably chosen enumeration of uniformly recursive languages containing at least all the languages from ). Furthermore, we consider the influence of set-drivenness and rearrangement-independence for learning devices that realize thesubset principle to different extents. Thereby we distinguish betweenstrong-monotonic, monotonic, andWeakmonotonic orconservative learning. The results obtained are threefold. First, rearrangement-independent learning does not constitute a restriction except in the case of monotonic learning. Next, we prove that for all but two of the learning models considered set-drivenness is a severe restriction. However, class-comprising set-drivenconservative learning is exactly as powerful as unrestricted class-comprisingconservative learning. Finally, the power of class-comprising set-driven learning in the limit is characterized by equating the collection of learnable indexed families with the collection of class-comprisingly conservatively inferable indexed families. These results considerably extend previous work done in the field (see, e.g., [20] and [5]). This is a substantially revised version of the authors' paper inProceedings of the 5th International Workshop on Algorithmic Learning Theory (ALT '94), Lecture Notes in Artificial Intelligence, Vol. 872, pp. 453–468, Springer-Verlag, Berlin. The first author has been partially supported by the German Ministry for Research and Technology (BMFT) under Grant No. 01 IW 101.     

Impact of Reactive Amphiphilic Copolymers on Mechanical Properties and Cell Responses of Fibrin‐Based Hydrogels

Mechanical properties of hydrogels can be modified by the variation of structure and concentration of reactive building blocks. One promising biological source for the synthesis of biocompatible hydrogels is fibrinogen. Fibrinogen is a glycoprotein in blood, which can be transformed enzymatically to fibrin playing an important role in wound healing and clot formation. In the present work, it is demonstrated that hybrid hydrogels with their improved mechanical properties, tunable internal structure, and enhanced resistance to degradation can be synthesized by a combination of fibrinogen and reactive amphiphilic copolymers. Water‐soluble amphiphilic copolymers with tunable molecular weight and controlled amounts of reactive epoxy side groups are used as reactive crosslinkers to reinforce fibrin hydrogels. In the present work, copolymers that can influence the mechanical properties of fibrin‐based hydrogels are used. The reactive copolymers increase the storage modulus of the hydrogels from 600 Pa to 30 kPa. The thickness of fibrin fibers is regulated by the copolymer concentration. It could be demonstrated that the fibrin‐based hydrogels are biocompatible and support cell proliferation. Their degradation rate is considerably slower than that of native fibrin gels. In conclusion, fibrin‐based hydrogels with tunable elasticity and fiber thickness useful to direct cell responses like proliferation and differentiation are produced.     

The meaning of rivers in Aotearoa New Zealand—Past and future

This paper examines how attitudes towards rivers in Aotearoa New Zealand have evolved since the country's settlement by Europeans, two centuries ago. For most of our postcolonial history, rivers have been viewed as something to be controlled and managed—even “improved.” But today, rivers are increasingly being recognized as embodying a broad range of values from the ecological to the spiritual—not simply as a “channel of water” that can be exploited for human ends. Although much of this evolving understanding stems from the advance in scientific knowledge, much too has its roots in our collective past.     

High Aspect Ratio Sub‐Micrometer Channels Using Wet Etching: Application to the Dynamics of Red Blood Cell Transiting through Biomimetic Splenic Slits

Nanoparticles delivering drugs, disseminating cancer cells, and red blood cells (RBCs) during splenic filtration must deform and pass through the sub‐micrometer and high aspect ratio interstices between the endothelial cells lining blood vessels. The dynamics of passage of particles/cells through these slit‐like interstices remain poorly understood because the in vitro reproduction of slits with physiological dimensions in devices compatible with optical microscopy observations requires expensive technologies. Here, novel microfluidic PDMS devices containing high aspect ratio slits with sub‐micrometer width are molded on silicon masters using a simple, inexpensive, and highly flexible method combining standard UV lithography and anisotropic wet etching. These devices enabled revealing novel modes of deformations of healthy and diseased RBCs squeezing through splenic‐like slits (0.6–2 × 5–10 × 1.6–11 µm³) under physiological interstitial pressures. At the slit exit, the cytoskeleton of spherocytic RBCs seemed to be detached from the lipid membrane whereas RBCs from healthy donors and patients with sickle cell disease exhibited peculiar tips at their front. These tips disappeared much slower in patients' cells, allowing estimating a threefold increase in RBC cytoplasmic viscosity in sickle cell disease. Measurements of time and rate of RBC sequestration in the slits allowed quantifying the massive trapping of spherocytic RBCs.     

Analytical study of the accuracy of discrete element simulations

The numerical errors was used to verify the correctness of key results. The truncation errors, which are larger than the round‐off errors by orders of magnitude, have a superlinear relationship with both the simulation time‐step and the interparticle collision speed. This remains the case regardless of the simulation details including the chosen contact model, particle size distribution, particle density or stiffness. Hence, the total errors can usually be reduced by choosing a smaller time‐step. Increasing the polydispersity in a simulation by including smaller particles necessitates choosing a smaller time‐step to maintain simulation stability and reduces the truncation errors in most cases. The truncation errors are increased by the dissipation of energy by frictional sliding or by the inclusion of damping in the system. The number of contacts affects the accuracy, and one can deduce that because 2D simulations contain fewer interparticle contacts than the equivalent 3D simulations, they therefore have lower accrued simulation errors. Copyright © 2016 John Wiley & Sons, Ltd.     

Efficiency enhancement of InP‐based inverted QD‐LEDs by incorporation of a polyethylenimine modified Al:ZnO layer

We report efficiency enhancement of indium phosphide (InP) quantum dot‐based light‐emitting diodes (QD‐LEDs) by using an polyethylenimine (PEI) surface modifier. By adapting a solution processed PEI layer on top of a aluminum doped zinc oxide (Al:ZnO) nanoparticle (NP) film, the leakage current of the inverted device was substantially suppressed. In addition, the electron injection into the conduction band edge (CBE) of InP/ZnSe/ZnS QDs was also facilitated by the low work function (WF) of the Al:ZnO film which was realized by the strong interfacial dipoles of the thin film of PEI. As a result, the charge balance in the inverted devices was controlled by the change of surface roughness, the WF and the thickness of neighboring layers via spin‐coating the PEI dissolved in alcohol mixture on the Al:ZnO layer such that the current efficiency was dramatically increased from 0.07 cd/A to 3.17 cd/A. The performance of our device is not comparable to Cd‐based devices; however, it shows the great potential for using an interfacial dipole layer to develop highly efficient InP‐based inverted QD‐LEDs.     

Modelling endurance and resumption times for repetitive one-hand pushing

This study’s objective was to develop models of endurance time (ET), as a function of load level (LL), and of resumption time (RT) after loading as a function of both LL and loading time (LT) for repeated loadings. Ten male participants with experience in construction work each performed 15 different one-handed repetaed pushing tasks at shoulder height with varied exerted force and duration. These data were used to create regression models predicting ET and RT. It is concluded that power law relationships are most appropriate to use when modelling ET and RT. While the data the equations are based on are limited regarding number of participants, gender, postures, magnitude and type of exerted force, the paper suggests how this kind of modelling can be used in job design and in further research.

Practitioner Summary: Adequate muscular recovery during work-shifts is important to create sustainable jobs. This paper describes mathematical modelling and presents models for endurance times and resumption times (an aspect of recovery need), based on data from an empirical study. The models can be used to help manage fatigue levels in job design.     

Governance of transitions towards sustainable development – the water–energy–food nexus in Cyprus

This paper presents a methodological framework to analyse sustainability innovations in the water–energy–food nexus and strategies for governing transition processes towards their widespread implementation. An application to a case study in Cyprus shows the interrelations of several sustainability innovations in the water, energy and food sectors, and specific learning requirements that need to be addressed to achieve a transition towards sustainable development. The framework helps to explore systematically responsibilities of different stakeholders for the implementation of innovations and thereby provides critical information for reflexive governance processes.     

Maize-nutrient response information applied across Sub-Saharan Africa

The profit potential for a given investment in fertilizer use can be estimated using representative crop nutrient response functions. Where response data is scarce, determination of representative response functions can be strengthened by using results from homologous crop growing conditions. Maize (Zea mays L.) nutrient response functions were selected from the Optimization of Fertilizer Recommendations in Africa (OFRA) database of 5500 georeferenced response functions determined from field research conducted in Sub-Saharan Africa. Three methods for defining inference domains for selection of response functions were compared. Use of the OFRA Inference Tool (OFRA-IT; http://agronomy.unl.edu/OFRA) resulted in greater specificity of maize N, P, and K response functions with higher R² values indicating superiority compared with using the Harvest Choice Agroecological Zones (HC-AEZ) and the recommendation domains of the Global Yield Gap Atlas project (GYGA-RD). The OFRA-IT queries three soil properties in addition to climate-related properties while the latter two options use climate properties only. The OFRA-IT was generally insensitive to changes in criteria ranges of 20–25% used in queries suggesting value in using wider criteria ranges compared with the default for information scarce crop nutrient response functions.