Fast Approximate Reconciliation of Set Differences

We present new, simple, efficient data structures for approximate reconciliation of set differences, a useful standalone primitive for peer-to-peer networks and a natural subroutine in methods for exact reconciliation. In the approximate reconciliation problem, peers A and B respectively have subsets of elements SA and SB of a large universe U. Peer A wishes to send a short message M to peer B with the goal that B should use M to determine as many elements in the set SB–SA as possible. To avoid the expense of round trip communication times, we focus on the situation where a single message M is sent. We motivate the performance tradeoffs between message size, accuracy and computation time for this problem with a straightforward approach using Bloom filters. We then introduce approximation reconciliation trees, a more computationally efficient solution that combines techniques from Patricia tries, Merkle trees, and Bloom filters. We present an analysis of approximation reconciliation trees and provide experimental results comparing the various methods proposed for approximate reconciliation.National Science Foundation (ANI-0093296, ANI-9986397, CCR-0118701, CCR-0121154); Alfred P. Sloan Research Fellowshi

Simple Load Balancing for Distributed Hash Tables

Distributed hash tables have recently become a useful building block for a variety of distributed applications. However, current schemes based upon consistent hashing require both considerable implementation complexity and substantial storage overhead to achieve desired load balancing goals. We argue in this paper that these goals can b e achieved more simply and more cost-effectively. First, we suggest the direct application of the "power of two choices" paradigm, whereby an item is stored at the less loaded of two (or more) random alternatives. We then consider how associating a small constant number of hash values with a key can naturally b e extended to support other load balancing methods, including load-stealing or load-shedding schemes, as well as providing natural fault-tolerance mechanisms

A Pragmatic Approach to DHT Adoption

Despite the peer-to-peer community's obvious wish to have its systems adopted, specific mechanisms to facilitate incremental adoption have not yet received the same level of attention as the many other practical concerns associated with these systems. This paper argues that ease of adoption should be elevated to a first-class concern and accordingly presents HOLD, a front-end to existing DHTs that is optimized for incremental adoption. Specifically, HOLD is backwards-compatible: it leverages DNS to provide a key-based routing service to existing Internet hosts without requiring them to install any software. This paper also presents applications that could benefit from HOLD as well as the trade-offs that accompany HOLD. Early implementation experience suggests that HOLD is practical

Strategies for Effective Online Course Development

Old Dominion University\u27s Civil Engineering Technology (CET) program has a successful history of distance education, with more than half of the student population comprised of distance learners. Distance learning delivery has traditionally been via satellite and videostreaming with students having the choice of asynchronous or synchronous options. The university is in the process of updating their distance learning technologies and has encouraged programs to migrate to an online modality of distance learning. Developing and delivering online courses requires different competencies and facilitation skills than video streamed synchronous delivery or face to face instruction. A course delivered online changes the teaching and learning dynamics. Courses must be learner-centered with a learning environment that addresses the new roles of the student and instructor. The instructor needs to get to know the students, and empower students to manage their learning experience while creating an online community among the students. The instructor takes on the role of a facilitator of learning, and students must take a more active role in the learning process. Students must be self-motivated, self-disciplined and willing to take ownership of their learning. The course content and layout are critical to successful student engagement and interaction with the instructor, the material, and with other students. Online courses must be developed for longevity, separated from a text that can be revised soon after the online course is launched. Course modules, focused on course topics, should use multiple resources, readings, mini-lectures, assignments, online quizzes, discussion boards, web links, and others, to achieve learning outcomes. As more programs move to online courses, understanding effective strategies for planning, designing and facilitating these courses becomes critical to success

Hydrogen Cyanamide Causes Reversible G2/M Cell Cycle Arrest Accompanied by Oxidation of the Nucleus and Cytosol

Hydrogen cyanamide (HC) has been widely used in horticulture to trigger bud burst following dormancy. Its use has been banned in some countries due to human health concerns, however the search for effective safe alternatives is delayed by lack of knowledge of the mechanism of HC action. Earlier studies demonstrate that HC stimulates the production of reactive oxygen species (ROS) and alters the rate of cell division. However, the relationships between HC effects on ROS, redox (reduction/oxidation) homeostasis and cell division are unknown. This study used Arabidopsis thaliana ((L.) Heynh.) seedlings expressing the redox reporter roGFP2 to measure the oxidation states of the nuclei and cytosol in response to HC treatment. The Cytrap dual cell cycle phase marker system and flow cytometry were used to study associated changes in cell proliferation. HC (1.5 mM) reversibly inhibited root growth during a 24 h treatment. Higher concentrations were not reversible. HC did not synchronise the cell cycle, in contrast to hydroxyurea. Rather, HC caused a gradual accumulation of cells in the G2/M phase and decline of G1/S phase cells, 16 to 24 h post-treatment. This was accompanied by increased oxidation of both the nuclei and cytosol. Taken together, these findings show that HC impairs proliferation of embryonic root meristem cells in a reversible manner through restriction of G2/M transition accompanied by increased cellular oxidation

Cognitive-Affective Processing, Sleep Quality, and Mood in Obstructive Sleep Apnea

OBJECTIVES : Extant experimental research implicates sleep disturbance as causal to dysregulation of emotional processes and neurocognitive functioning. Clinical research with psychiatric samples suggests that sleep disturbance may be an etiological or sustaining factor in certain conditions, rather than solely a symptom. Recently proposed models have hypothesized cognitive-affective processing (CAP) as a potential mediator for the relationship between sleep disturbance and depressed mood. This study investigated relevant neuropsychological and sleep-physiological variables to explore the applicability of this type of model within a sleep apnea referral sample. METHODS: 61 participants referred for polysomnogram also completed self-report measures of mood and sleep, as well as a neuropsychological battery consisting of standard neurocognitive measures and novel cognitive-affective processing counterpart measures. RESULTS: Correlational and ANCOVA analyses suggested cognitive-affective processing measures were potentialy more sensitive toward dysfunction secondary to sleep-disordered breathing than standard neurocognitive measures. Regression analyses were mixed, while most of the a priori model was confirmed, unexpected null findings between sleep physiology and depression suggested poor fit for this sample. Exploratory analyses suggest there may be a more complex model relating the three constructs of interest, incorporating related sleep physiology and affective state constructs. CONCLUSIONS: Within our sample, findings suggest dysfunctional sleep-breathing physiology impacts the affective valence of previously identified subcortical-frontal retrieval dysfunction. The relative absence of findings within standard measures suggests that cognitive-affective processing measures may be more sensitive to finer gradients of sleep disturbance severity. Additionally, this finding is independent of the incidental findings that the cognitive-affective processing is sensitive to negative mood and psychological distress about lack of sleep, suggesting the neurocognitive measure is sensitive to both physiological and psychological sequelae. This study provides initial support for a neuropsychological measure of how humans process emotionally-laden information, which has significant potential for use in research and clinical fields. Future research will generate normative data for the novel cognitive-affective processing measures, as well as explore the original and expanded model of negative mood within other psychiatric and neurological samples

Green Infrastructure Training for Veterans

The Environmental Protection Agency launched a Strategic Agenda to Protect Waters and Build More Livable Communities through Green Infrastructure in April of 2011. This initiative supports local communities in using green infrastructure to manage rain water while creating co-benefits of green space, which makes communities more attractive and livable. (EPA) In the fall of 2014 the Environmental Protection Agency along with the U.S. Department of Agriculture, U.S. Department of Defense, U.S. Department of Energy, U.S. Department of Housing and Urban Development, U.S. Department of the Interior and U.S. Department of Transportation signed a federal letter of support for green infrastructure recognizing it as an important tool for building resilience to climate change impacts such as increased heavy rainfall and heat island effect. Each agency committed to taking specific action to promote green infrastructure including but not limited to: creating alliances, providing community assistance, funding, training, development of metrics to assess performance of green infrastructure, and promotion best practices. (Federal) The City of XXXX, the Green Infrastructure Center, Inc., and X University have collaborated on a National Fish and Wildlife Federation Grant titled Developing a Green Infrastructure Plan and Network for the X River Network . As part of the project X University will provide a training program to prepare Veterans for the green jobs of the future. Green infrastructure projects can provide business and employment opportunities for veterans. This project includes a 20 hour educational course for veterans to educate them about the green infrastructure industry, business and employment opportunities in green infrastructure and green infrastructure storm water management techniques. Hands-on training will be incorporated in the course work. This program will develop a base level certification that will qualify recipients for more advanced and specialized programs. This green infrastructure training certificate will be coordinated with other green infrastructure education certifications and programs in a stackable manner to provide a transparent track for career advancement, which will benefit employers and the green infrastructure industry. This paper will highlight pre- and post training survey results and provide insight into the progress of the veterans transitioning to this employment area

Gene expression signatures modulated by epidermal growth factor receptor activation and their relationship to cetuximab resistance in head and neck squamous cell carcinoma.

BACKGROUND: Aberrant activation of signaling pathways downstream of epidermal growth factor receptor (EGFR) has been hypothesized to be one of the mechanisms of cetuximab (a monoclonal antibody against EGFR) resistance in head and neck squamous cell carcinoma (HNSCC). To infer relevant and specific pathway activation downstream of EGFR from gene expression in HNSCC, we generated gene expression signatures using immortalized keratinocytes (HaCaT) subjected to ligand stimulation and transfected with EGFR, RELA/p65, or HRASVal12D. RESULTS: The gene expression patterns that distinguished the HaCaT variants and conditions were inferred using the Markov chain Monte Carlo (MCMC) matrix factorization algorithm Coordinated Gene Activity in Pattern Sets (CoGAPS). This approach inferred gene expression signatures with greater relevance to cell signaling pathway activation than the expression signatures inferred with standard linear models. Furthermore, the pathway signature generated using HaCaT-HRASVal12D further associated with the cetuximab treatment response in isogenic cetuximab-sensitive (UMSCC1) and -resistant (1CC8) cell lines. CONCLUSIONS: Our data suggest that the CoGAPS algorithm can generate gene expression signatures that are pertinent to downstream effects of receptor signaling pathway activation and potentially be useful in modeling resistance mechanisms to targeted therapies