3,040 research outputs found
Impact of Conductive Education on Individuals with Stroke Syndrome
The purpose of this study was to investigate the impact of Conductive Education (CE) on adults with chronic stroke, replicating and expanding upon the study at Cannon Hill House (CHH) by Brown et al. We hypothesized that completing the CE program would improve function and change neural connectivity. CE is a transdisciplinary, motor-learning based intervention which uses multiple facilitations including manual facilitation, equipment, rhythmic intention (a cadence facilitation), first person verbal articulation, and the group environment to impact a personâs motor learning and rehabilitation. An aim of this pilot study was to replicate and expanded upon a previous study examining the impact of CE as an intervention for adults with chronic stroke.
The location and severity of damage to the brain after a stroke influences the extent of functional limitations experienced by the stroke survivor. After injury, measurable physiological changes can be correlated with functional clinical measures. With physical rehabilitation interventions, functional impairments can be lessened, presumably through mechanisms of neuroplasticity. Thus a personâs participation may improve as a result of improved performance. Though interventions are often effective for restoring at least partial function for individuals with stroke, little is known about what underlies the positive results for specific intervention
Promoter decoding of transcription factor dynamics involves a trade-off between noise and control of gene expression
Numerous transcription factors (TFs) encode information about upstream signals in the dynamics of their activation, but how downstream genes decode these dynamics remains poorly understood. Using microfluidics to control the nucleocytoplasmic translocation dynamics of the budding yeast TF Msn2, we elucidate the principles that govern how different promoters convert dynamical Msn2 input into gene expression output in single cells. Combining modeling and experiments, we classify promoters according to their signal-processing behavior and reveal that multiple, distinct gene expression programs can be encoded in the dynamics of Msn2. We show that both oscillatory TF dynamics and slow promoter kinetics lead to higher noise in gene expression. Furthermore, we show that the promoter activation timescale is related to nucleosome remodeling. Our findings imply a fundamental trade-off: although the cell can exploit different promoter classes to differentially control gene expression using TF dynamics, gene expression noise fundamentally limits how much information can be encoded in the dynamics of a single TF and reliably decoded by promoters
TK: The Twitter Top-K Keywords Benchmark
Information retrieval from textual data focuses on the construction of
vocabularies that contain weighted term tuples. Such vocabularies can then be
exploited by various text analysis algorithms to extract new knowledge, e.g.,
top-k keywords, top-k documents, etc. Top-k keywords are casually used for
various purposes, are often computed on-the-fly, and thus must be efficiently
computed. To compare competing weighting schemes and database implementations,
benchmarking is customary. To the best of our knowledge, no benchmark currently
addresses these problems. Hence, in this paper, we present a top-k keywords
benchmark, TK, which features a real tweet dataset and queries with
various complexities and selectivities. TK helps evaluate weighting
schemes and database implementations in terms of computing performance. To
illustrate TK's relevance and genericity, we successfully performed
tests on the TF-IDF and Okapi BM25 weighting schemes, on one hand, and on
different relational (Oracle, PostgreSQL) and document-oriented (MongoDB)
database implementations, on the other hand
Popular critiques of consultancy and a politics of management learning?
In this short article, I argue that popular business discourse on the role of management consultancy in the promotion and translation of management ideas is often critical, informed by more or less implicit ethical and political concerns with employee security, equity, openness and the transparency and legitimacy of responsibility. These concerns are, in part, âsayableâ because their object is seen as a scapegoat for management. Nevertheless, combined with the popular form of their expression, they can support and legitimize critical studies of management learning, a discipline which otherwise has become overly concerned with processual and situational phenomena at the expense of broader political dynamics and of the content and consequences of management and management knowledg
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A systematic genetic screen for genes involved in sensing inorganic phosphate availability in Saccharomyces cerevisiae
Saccharomyces cerevisiae responds to changes in extracellular inorganic phosphate (P_i) availability by regulating the activity of the phosphate-responsive (PHO) signaling pathway, enabling cells to maintain intracellular levels of the essential nutrient P_i. P_i-limitation induces upregulation of inositol heptakisphosphate (IP_7) synthesized by the inositol hexakisphosphate kinase Vip1, triggering inhibition of the Pho80/Pho85 cyclin-cyclin dependent kinase (CDK) complex by the CDK inhibitor Pho81, which upregulates the PHO regulon through the CDK target and transcription factor Pho4. To identify genes that are involved in signaling upstream of the Pho80/Pho85/Pho81 complex and how they interact with each other to regulate the PHO pathway, we performed genome-wide screens with the synthetic genetic array method. We identified more than 300 mutants with defects in signaling upstream of the Pho80/Pho85/Pho81 complex, including AAH1, which encodes an adenine deaminase that negatively regulates the PHO pathway in a Vip1-dependent manner. Furthermore, we showed that even in the absence of VIP1, the PHO pathway can be activated under prolonged periods of P_i starvation, suggesting complexity in the mechanisms by which the PHO pathway is regulated
Ultrashort-pulse laser with an intracavity phase shaping element
A novel ultrashort-pulse laser cavity configuration that incorporates an intracavity deformable mirror as a phase control element is reported. A user-defined spectral phase relation of 0.7 radians relative shift could be produced at around 1035 nm. Phase shaping as well as pulse duration optimization was achieved via a computer-controlled feedback loop
Extensible Component Based Architecture for FLASH, A Massively Parallel, Multiphysics Simulation Code
FLASH is a publicly available high performance application code which has
evolved into a modular, extensible software system from a collection of
unconnected legacy codes. FLASH has been successful because its capabilities
have been driven by the needs of scientific applications, without compromising
maintainability, performance, and usability. In its newest incarnation, FLASH3
consists of inter-operable modules that can be combined to generate different
applications. The FLASH architecture allows arbitrarily many alternative
implementations of its components to co-exist and interchange with each other,
resulting in greater flexibility. Further, a simple and elegant mechanism
exists for customization of code functionality without the need to modify the
core implementation of the source. A built-in unit test framework providing
verifiability, combined with a rigorous software maintenance process, allow the
code to operate simultaneously in the dual mode of production and development.
In this paper we describe the FLASH3 architecture, with emphasis on solutions
to the more challenging conflicts arising from solver complexity, portable
performance requirements, and legacy codes. We also include results from user
surveys conducted in 2005 and 2007, which highlight the success of the code.Comment: 33 pages, 7 figures; revised paper submitted to Parallel Computin
Recent key developments in nanoscale reliability and failure analysis techniques for advanced nanoelectronics devices
Last decade has witnessed an aggressive scaling of CMOS technology nodes pushing it all the way down to sub-10nm and this scaling trend looks positive for the next two-three nodes as well down to 5nm. This push for scaling of the technology node has created a need for using material characterization techniques with (sub)nanometer probe resolution to characterize these advanced nanoelectronic devices - to observe and understand the underlying thermodynamics and kinetics of the physical phenomenon at the nanometer scale in real-time. Among these advanced characterization techniques, transmission election microscopy (TEM) and scanning probe microscopy (SPM), as well as the techniques derived from these, have become critical and instrumental to failure analysis and for evaluation of key design metrics for reliability studies. In this work, we present the different case studies using these two techniques which we have employed for studying both advanced logic and memory devices. High resolution TEM (HRTEM) has been used for both RRAM and gate oxide reliability studies due to its multiple compositional characterization capabilities with sub-nm resolution. TEM can routinely achieve a resolution around 0.1nm and thus can provide tremendous information related to structure (Diffraction Pattern) and composition (Electron Energy Loss Spectroscopy). Ex-situ TEM techniques (supported by Focused Ion Beam (FIB)) have allowed us to perform diverse electrical and thermal testing on devices. We have found concrete evidence of FinFET device degradation recently [1]. We have also employed in-situ TEM techniques (facilitated by scanning tunneling microscopy (STM) and the thermal holder) to observe the degradation behavior of metal-dielectric stacks in real-time [2]. The in-situ TEM technique has provided insight into the direct and solid time sequential evolution of failure behavior in RRAM devices. Additionally, 3D tomography characterization of the defect and failure spot has been acquired by tilting the sample and collecting the sequential images at different angles [3]. This technique of 3D tomography is a very powerful one for defect reorganization and for root cause analysis of failure mechanism. Conductive atomic force microscopy (CAFM) and STM are two techniques, belonging to a large pool of available SPM tools, which we have used for breakdown studies in ultra-thin HfO2 and other high-Îș dielectrics as well as multi-layered fluorinated graphene (FG) stacks. With a resolution, down to ~10nm and ~0.1nm for CAFM and STM respectively under ultra-high vacuum (UHV) conditions, we have applied these tools to measure electrical properties (I-V and dI/dV) at grain and grain boundary spots in ultra-thin polycrystalline HfO2 dielectrics [4] as well as to understand the breakdown mechanism in FG stacks [5]. We have also explored the local spectroscopy capabilities (of both STM and CAFM) for the measurement of random telegraph noise (RTN) in blanket HfO2 films. Using bias dependent RTN measurements, it has been possible to quantify the position of the defect in the probed location of the dielectric. Interestingly, these dielectric breakdowns and RTN measurements at the nanoscale have also provided experimental evidence of defect clustering in polycrystalline dielectrics and possible existence of the metastable nature of oxygen vacancy (VO) defect in HfO2 respectively [6]. CAFM has also been explored to study the role of VO in HfO2 based RRAM stacks for ultra-low power memory applications where the signature of sub-quantum conductance based resistive switching has been experimentally observed [7]. We strongly believe that these tools and techniques would play an indispensable role in unveiling the underlying physics of the nanoscale physical phenomenon for existing as well as emerging materials and 2D/3D devices. References: [1] S. Mei et al., IEDM (2016). [2] K. L. Pey et al., IRPS (2010). [3] S. Mei et al., Unpublished. [4] K. Shubhakar et al., Micro. Engineering (2013). [5] A. Ranjan et al., IRPS (2017, Accepted). [6] A. Ranjan et al., IRPS (2016
Phase Mixing of Alfvén Waves Near a 2D Magnetic Null Point
The propagation of linear Alfvén wave pulses in an inhomogeneous plasma near a 2D coronal null point is investigated. When a uniform plasma density is considered, it is seen that an initially planar Alfvén wavefront remains planar, despite the varying equilibrium Alfvén speed, and that all the wave collects at the separatrices. Thus, in the non-ideal case, these Alfvénic disturbances preferentially dissipate their energy at these locations. For a non-uniform equilibrium density, it is found that the Alfvén wavefront is significantly distorted away from the initially planar geometry, inviting the possibility of dissipation due to phase mixing. Despite this however, we conclude that for the Alfvén wave, current density accumulation and preferential heating still primarily occur at the separatrices, even when an extremely non-uniform density profile is considered
Decomposable representations and Lagrangian submanifolds of moduli spaces associated to surface groups
In this paper, we construct a Lagrangian submanifold of the moduli space
associated to the fundamental group of a punctured Riemann surface (the space
of representations of this fundamental group into a compact connected Lie
group). This Lagrangian submanifold is obtained as the fixed-point set of an
anti-symplectic involution defined on the moduli space. The notion of
decomposable representation provides a geometric interpretation of this
Lagrangian submanifold
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