Dynamic Self Research Articles

Dynamic self assembly of confined active nanoparticles

We report the dynamic self-assembly of chemically propelled nanoscale building blocks (NBBs) under confinement using reactive molecular dynamics simulations. The NBBs are hollow rectangles with one side open (tail) to expose the catalysts inside to the fuel environment. Adjacent NBBs can self assembly into tail–tail or tail–head (the side opposite to the tail) pairs. It was found that chemical propulsion forces unlock many tail–tail pairs but not tail–head pairs. Although the distributions of both tail–tail and tail–head pairs are orientation-dependent with respect to the confining wall, the effect of chemistry seems to be orientation-independent.

Leakage Current Reduction Techniques for 7T SRAM Cell in 45 nm Technology

In this paper the impact of gate leakage on 7T static random access memory (SRAM) is described and three techniques for reducing gate leakage currents and sub threshold leakage currents are examined. In first technique, the supply voltage is decreased. In the second techniques the voltage of the ground node is increased. While in third technique the effective voltage across SRAM cell Vd = 0.348V and Vs = 0.234V are observed. In all the techniques the effective voltage across SRAM cell is decreased in stand-by mode using a dynamic self controllable voltage level (SVL) switch. Simulation results based on cadence tool for 45 nm technology show that the techniques in which supply voltage level is reduced is more efficient in reducing gate leakage than the one in which ground node voltage is increased. Result obtained show that 437 FA reductions in the leakage currents of 7T SRAM can be achieved.

The dynamics and trajectory of creative consumption practices as revealed by the postmodern game of geocaching

Through a comprehensive exploration of the no-limits postmodern game of geocaching, two researchers shed light on the dynamics and trajectory of creative consumption practices. They reveal how they overlap with other practices, the process of contamination they result in and the way they foster dynamic and playful embedded selves of consumers and actors involved in this process. The authors highlight the need for researchers to understand consumption practices as systems of entangled and evolutive practices that mingle in complex ways.

Structure Formation in Active Actin Networks

The actin cytoskeleton determines local mechanical and structural properties of a eukaryotic cell. To adapt to their environment, constant self-organized rearrangement processes of the actin cytoskeleton are key requirements. To shed light on the principles underlying these dynamic self organization processes we investigate a minimal reconstituted active system consisting of actin filaments, crosslinking molecules and molecular motor filaments.By means of quantitative fluorescence microscopy and image analysis, we demonstrate, that these minimal systems exhibit a generic structure formation mechanism. The intricate interplay between force generation by molecular motors and the stabilization of the network by crosslinking proteins is identified to be responsible for the highly dynamic structure formation process. These competing mechanisms result in an anomalous transport dynamics, with a superdiffusive behavior also found in intracellular dynamics.View Large Image | View Hi-Res Image | Download PowerPoint Slide

Call for Manuscripts: Assessment

Assessment that is a continuous, integrated part of mathematics instruction will guide and enhance learning for all students. In addition to evaluating students' conceptual understanding and procedural fluency, assessment also informs instructional decisions. Assessment is a dynamic self–reflective process for both teachers and students that is at the core of significant mathematics content, teaching practices, and student learning. A key aspect of instructional decision making is the alignment of the curriculum and instruction with assessment. For example, assessment techniques may include open–ended questions, constructed-response tasks, selected–response items, performance tasks, observations, conversations, journals, and portfolios. In the spirit of NCTM's Assessment Principle and its focus on reasoning and sense making, the MT Editorial Panel seeks manuscripts that address but are not limited to the following topics:

A Clustering Method Based on Dynamic Self Organizing Trees for Post-Pareto Optimality Analysis

Multiple objective optimization involves the simultaneous optimization of several objective functions. Solving this type of problem involves two stages; the optimization stage and the post-Pareto analysis stage. The first stage focuses in obtaining a set of nondominated solutions while the second one involves the selection of one solution from the Pareto set. Most of the work found in the literature focuses in the first stage. However, the decision making stage is as important as obtaining the set of nondominated solutions. Selecting one solution over others, or reducing the number of alternatives to choose from is not a simple task since the Pareto-optimal set can potentially contain a very large number of solutions. This paper introduces the dynamic self organizing tree algorithm as a method to perform post-Pareto analysis. This algorithm offers two main advantages: there is no need to provide an initial number of clusters, and at each hierarchical level, the algorithm optimizes the number of clusters, and can reassign data from previous hierarchical levels in order to rearrange misclustered data. The proposed method is tested in a well-known multiple objective optimization problem in order to show the performance of the algorithm.

The application of self-directed learning in a marketing strategy capstone course

Capstone courses can create a space for students and educators to act as co–producers of desired learning outcomes which are directly relevant to the world of work. This study uses an auto–ethnographic case study approach to demonstrate how a mixed model learning approach evolved in a capstone marketing strategy unit in a marketing major at an Australian university. Student feedback on the course demonstrates the benefits of using dynamic self–directed learning tools including a marketing strategy simulation game and its associated reflective journal as an adjunct to the traditional static case study and essay–based pedagogies. The necessity for such an approach is based on the premise that the world of work in which the student is about to enter is one which is being increasingly affected by complexity and uncertainty and requires a different set of learning tools to equip students for this kind of work context.

Collection mode surface plasmon fibre sensors: A new biosensing platform

Sensors based on surface plasmon resonance (SPR) allow rapid, label-free, highly sensitive detection, and indeed this phenomenon underpins the only label-free optical biosensing technology that is available commercially. In these sensors, the existence of surface plasmons is inferred indirectly from absorption features that correspond to the coupling of light into a thin metallic film. Although SPR is not intrinsically a radiative process, when the metallic coating which support the plasmonic wave exhibits a significant surface roughness, the surface plasmon can itself couple to the local photon states, and emit light. Here we show that using silver coated optical fibres, this novel SPR transducing mechanism offers significant advantages compare to traditional reflectance based measurements such as lower dependency on the metallic thickness and higher signal to noise ratio. Furthermore, we show that more complex sensor architectures with multiple sensing regions scattered along a single optical fibre enable multiplexed detection and dynamic self referencing of the sensing signal. Moreover, this alternative approach allows to combine two different sensing technologies, SPR and fluorescence sensing within the same device, which has never been demonstrated previously. As a preliminary proof of concept of potential application, this approach has been used to demonstrate the detection of the seasonal influenza A virus.

Mechanisms of electric-field-induced alignment of block copolymer lamellae

We demonstrate that two mechanisms of lamellae reorientation observed experimentally under applied electric field [A. Boker H. Elbs, H. Hansel, A. Knoll, S. Ludwigs, H. Zettl, V. Urban, V. Abetz, A. H. E. Muller and G. Krausch, Phys. Rev. Lett., 2002, 89, 135502] which have been previously described within dynamic self consistent field theory [A. V. Zvelindovsky and G. J. A. Sevink, Phys. Rev. Lett., 2003, 90, 049601] can be fully explained within a much more simple model using the Ginzburg–Landau Hamiltonian. A third alignment mechanism has been identified which was not previously reported. A more complete picture of reorientation under electric field emerges that clarifies the crucial role of structural defects.

Vascular morphogenesis by adult bone marrow progenitor cells in three-dimensional fibrin matrices

The neovascularization of tissues is accomplished by two distinct processes: de novo formation of blood vessels through the assembly of progenitor cells during early prenatal development (vasculogenesis), and expansion of a pre-existing vascular network by endothelial cell sprouting (angiogenesis), the main mechanism of blood vessel growth in postnatal life. Evidence exists that adult bone marrow (BM)-derived progenitor cells can contribute to the formation of new vessels by their incorporation into sites of active angiogenesis. Aim of this study was to investigate the in vitro self-organizing capacity of human BM mononuclear cells (BMMNC) to induce vascular morphogenesis in a three-dimensional (3D) matrix environment in the absence of pre-existing vessels. Whole BMMNC as well as the adherent and non-adherent fractions of BMMNC were embedded in fibrin gels and cultured for 3–4 weeks without additional growth factors. The expression of hematopoietic-, endothelial-, smooth muscle lineage, and stem cell markers was analyzed by immunohistochemistry and confocal laser-scanning microscopy. The culture of unselected BMMNC in 3D fibrin matrices led to the formation of cell clusters expressing the endothelial progenitor cell (EPC) markers CD133, CD34, vascular endothelial growth factor receptor (VEGFR)-2, and c-kit, with stellar shaped spreading of peripheral elongated cells forming tube-like structures with increasing complexity over time. Cluster formation was dependent on the presence of both adherent and non-adherent BMMNC without the requirement of external growth factors. Developed vascular structures expressed the endothelial markers CD34, VEGFR-2, CD31, von Willebrand Factor (vWF), and podocalyxin, showed basement-membrane-lined lumina containing CD45 + cells and were surrounded by α-smooth muscle actin (SMA) expressing mural cells. Our data demonstrate that adult human BM progenitor cells can induce a dynamic self organization process to create vascular structures within avascular 3D fibrin matrices suggesting a possible alternative mechanism of adult vascular development without involvement of pre-existing vascular structures.

Connectionism and Self: James, Mead, and the Stream of Enculturated Consciousness

William James conceptualized I, the self as subject as a stream of consciousness. When this conception is augmented with George Herbert Mead's view of self as a radically socialized and enculturated process, a result is the James-Mead model of dynamic self as a stream of enculturated consciousness. In this paper, we argue that connectionism is best suited to theorize this challenging notion. Based on the view that a connectionist model should describe psychological processes that carry out psychological functions grounded in a biological living system, we propose the I-SELF (Imitative and Sequence Learning Functional) model, which is designed to capture the temporal dynamics of a stream of consciousness whose content can be acquired via symbolically mediated social interaction with others in society. We identify four implications of the James-Mead model of dynamic self (embodiment, narrative and self, individual and collective self, and culture and self), and report computer simulations to show the utility of I-SELF in conceptualizing the dynamic self-processes in the contemporary social psychological literature. Theoretical and metatheoretical implications of the connectionist approach to self are discussed.

Gaps in the Mapping between Simulations and Self: Concerns with the Proposed Neural Network Model

We were impressed with the authors' scholarship and with their ambitious attempt to provide a more explicit model of the James-Mead dynamic self. Our comment will focus on the simulations themselves and their meaning, since in several of the simulations we find the mapping between the concrete simulation and the authors' conceptual point either difficult to under stand or hard to justify. In the following we systemat ically consider each of their four simulations and the issues we have with them, as well as suggesting in sev eral places what kind of simulation we believe would have been more appropriate. On a more general point, it is not clear to us why the authors take the time to talk about the neuroscience data on the brain centers involved in sequence learning and on the potential role of mirror neurons in sequence learning. It is already well known that humans can do sequence learning and that they can imitate others. The neuroscience data they cite does not add anything to that argument. It would make sense to discuss the neuroscience data if their model was inspired by it or constrained by it in some way, but we don't see how the neuroscience data informs their model in any way. However, we would be happy if the authors could provide an explicit account of how the neuroscience data informs their simulations.

Time, Culture, and Stories of the Self

The theoretical core of the James-Mead model of the dynamic self (Kashima, Gurumurthy, Ouschan, Chong, & Mattingley, 2007) takes seriously both the temporal nature of identity and the fundamental s...

Post-Migratory Experiences of Newcomer Female Youth: Self-Esteem and Identity Development

This study explored the post-migratory experiences of newcomer female youth attending secondary school within a multi-cultural context. Focus groups were held with 10 newcomer female youth, in Toronto, Canada. Data were also collected through focus groups or in-depth interviews with school educators, parents, and school and community health center workers. In addition, the Current Self-Esteem (CSE) instrument was utilized to examine the global self-esteem of youth and the influences on their self-esteem. The average age of youth participants was 17 years old and their average age of immigration to Canada was 13.9 years old. The average score for the CSE was 7.9, which indicated that respondents felt, in general, good about themselves. Among the influences on youth's self-esteem were those related to Self, School, Relationships, Achievements and Lifestyle. The emerging sub-themes of the Self-Concept theme, arising from the qualitative data, consisted of Dynamic Self, Silenced Self, Cultural Identity, Female Role Models, Future Aspirations. The impact of the resettlement process on the self-esteem and identity of newcomer females is considered. It is concluded that in multi-cultural and post-migration societies multi-sectoral and context-specific mental health promotion strategies and policies are needed for youth.

Checklist for law firm mergers

my hypothesis on the thinking behind this list is that libraries are organisations which are dynamic self evolving complex systems and so i have applied the simple systems theory template to how to merge two libraries. i think the key thing to remember is that systems cannot change radically or quickly and that they depend on feed-back to adjust their equilibrium. that said it follows that any merger, with its implications of big rapid change, will be difficult for any library system. it will be essential to keep open channels of communication and feed-back both within the immediate environment (the law firms themselves) and the external environment (publishers, service providers, journal subscriptions)

Dynamic self organizing maps for discovery and sharing of knowledge in multi agent systems

This paper presents a multi agent system which provides a method for cooperation and coordination among agents using collective reasoning. There are two types of agents in the system: distributed agents and a central administrator agent. The distributed agents provide local knowledge extraction tasks and communicate it to the central administrator agent. The central administrator agent builds a global picture about the problem domain using the local knowledge of each agent. It uses the Growing Self Organizing Map (GSOM), which is a dynamic version of the Self Organizing Map (SOM) for analyzing the global knowledge. The system differs from similar systems which employ central administrator functionality as the central administrator agent in the proposed system is capable of autonomously refining the task model of the distributed agents and dynamically determining the efficient number of agents required in the system.

Challenge and Success: A Qualitative Study of the Career Development of Highly Achieving Women With Physical and Sensory Disabilities.

This qualitative study examined the career development experiences of 17 highly achieving women with physical and sensory disabilities. Interviews were conducted and data were analyzed using modified grounded theory strategies (A. L. Strauss & J. Corbin, 1998). The emergent theoretical model was conceptualized as a system of influences organized around a core Dynamic Self, which included identity constructs (disability, gender, racial/ethnic/cultural), personality characteristics, and belief in self. Myriad contextual inputs included Developmental Opportunities (education, peer influences), Family Influences (background and current), Disability Impact (ableism, stress and coping, health issues), Social Support (disabled and nondisabled communities, role models and mentors), Career Attitudes and Behaviors (work attitudes, success strategies, leadership/pioneering), and Sociopolitical Context (social movements, advocacy). Implications for theory, research, practice, and policy are discussed.

Dynamical excitonic effects in metals and semiconductors.

The dynamics of an electron-hole pair induced by the time-dependent screened Coulomb interaction is discussed. In contrast to the case where the static electron-hole interaction is considered we demonstrate the occurrence of important dynamical excitonic effects in the solution of the Bethe-Salpeter equation. This is illustrated in the calculated absorption spectra of noble metals (copper and silver) and silicon. Dynamical corrections strongly affect the spectra, partially canceling dynamical self-energy effects and leading to good agreement with experiment.

Dynamics of self assembly of magnetized disks rotating at the liquid-air interface.

This paper is a theoretical study of dynamic self assembly in a system of millimeter-sized magnetized disks floating at a liquid-air interface and spinning under the influence of a rotating magnetic field. Equations of motions are derived that account for the hydrodynamic and magnetic forces acting in the system. Numerical integration of these equations predicts formation of ordered structures of spinning disks; the simulated structures reproduce the patterns observed experimentally.

Simulation of magnetic component models in electric circuits including dynamic thermal effects

It is essential in the simulation of power electronics applications to model magnetic components accurately. In addition to modeling the nonlinear hysteresis behavior, eddy currents and winding losses must be included to provide a realistic model. In practice the losses in magnetic components give rise to significant temperature increases which can lead to major changes in the component behavior. In this paper a model of magnetic components is presented which integrates a nonlinear model of hysteresis, electro-magnetic windings and thermal behavior in a single model for use in circuit simulation of power electronics systems. Measurements and simulations are presented which demonstrate the accuracy of the approach for the electrical, magnetic and thermal domains across a variety of operating conditions, including static thermal conditions and dynamic self heating.