14,652 research outputs found
The Art of War: Beyond Memory-one Strategies in Population Games
We define a new strategy for population games based on techniques from
machine learning and statistical inference that is essentially uninvadable and
can successfully invade (significantly more likely than a neutral mutant)
essentially all known memory-one strategies for the prisoner's dilemma and
other population games, including ALLC (always cooperate), ALLD (always
defect), tit-for-tat (TFT), win-stay-lose-shift (WSLS), and zero determinant
(ZD) strategies, including extortionate and generous strategies. We will refer
to a player using this strategy as an "information player" and the specific
implementation as . Such players use the history of play to identify
opponent's strategies and respond accordingly, and naturally learn to cooperate
with each other.Comment: 16 pages, 4 figure
Comprehensive Detection of Genes Causing a Phenotype using Phenotype Sequencing and Pathway Analysis
Discovering all the genetic causes of a phenotype is an important goal in
functional genomics. In this paper we combine an experimental design for
multiple independent detections of the genetic causes of a phenotype, with a
high-throughput sequencing analysis that maximizes sensitivity for
comprehensively identifying them. Testing this approach on a set of 24 mutant
strains generated for a metabolic phenotype with many known genetic causes, we
show that this pathway-based phenotype sequencing analysis greatly improves
sensitivity of detection compared with previous methods, and reveals a wide
range of pathways that can cause this phenotype. We demonstrate our approach on
a metabolic re-engineering phenotype, the PEP/OAA metabolic node in E. coli,
which is crucial to a substantial number of metabolic pathways and under
renewed interest for biofuel research. Out of 2157 mutations in these strains,
pathway-phenoseq discriminated just five gene groups (12 genes) as
statistically significant causes of the phenotype. Experimentally, these five
gene groups, and the next two high-scoring pathway-phenoseq groups, either have
a clear connection to the PEP metabolite level or offer an alternative path of
producing oxaloacetate (OAA), and thus clearly explain the phenotype. These
high-scoring gene groups also show strong evidence of positive selection
pressure, compared with strictly neutral selection in the rest of the genome
The Art of Humorous Song: Examining Humorous Songs Through the Lens of Selected Song Sets
The Art of Humorous Song: Examining Humorous Songs Through the Lens of Selected Song Set
Why Beginning Teachers Persist in the Profession and the Impact of Induction and Mentoring
With 46% of new teachers leaving the profession within the first five years, many states have mandated induction programs. This study sought to understand what beginning teachers in rural Maine perceive as the greatest factors impacting their persistence in education, and the perceived impact of induction and mentoring on their persistence. A mixed-methods approach yielded findings that indicated the greatest perceived factors are: working with students, collaborating with peers, and administrative support. Induction and mentoring perceptions were both positive and negative. Recommendations are directed at school leaders who must support teachers by providing time for collaboration and networking, and implementing purposeful induction and mentoring activities.(1 As cited in Andrews, Gilbert & Martin, 2012
Life cycle cost analysis for joint elimination retrofits and thermal loading on Colorado bridges
2017 Spring.Includes bibliographical references.Bridge expansion joints are a particularly troublesome component of bridges and many Departments of Transportation (DOTs) are looking for a solution to deteriorating expansion joints on highway bridges. Bridge expansion joints create a break in the structural continuity of a bridge allowing clogging gravels and corroding chlorides to enter. They are designed to absorb thermal movements of the bridge between two bridge elements. There are three main issues regarding expansion joint: maintenance, knowledge about thermal movements, and costs. In order to prevent deterioration due to expansion joints the joints must be cleaned regularly and replaced promptly after failure. However, most DOTs do not have the personnel, time or resources to maintain expansion joints in their districts which leads to bridge deterioration. Other similar maintenance and component issues have been addressed using a Life Cycle Cost Analysis. For this to be used on expansion joints the three main issues of thermal knowledge, maintenance, and costs must first be addressed. The main goal of this project is to help transportation agencies make better decisions about bridge expansion joints. The specific objectives of this study are to 1) expand understanding of thermal loading effects on bridge expansion joints and 2) conduct a LCCA for joint elimination and retrofits for bridges in Colorado. These objectives were accomplished utilizing data from in field instrumentation and finite element models. The study has been developed jointly between the Colorado Department of Transportation (CDOT) and researchers at Colorado State University Three main tasks were conducted to achieve the objectives: 1) collect and analyze long-term thermal loading data from existing bridges to assess thermal loading impacts on joints; 2) perform a parametric study using a calibrated finite element model to further understanding of joint behavior and retrofit options under thermal loads; 3) perform a LCCA for bridge expansion joint retrofitting including impacts on bridge superstructure. The significance of this work includes the results of the data collection and analysis, the parametric study, and the LCCA findings. The preliminary data on the concrete bridge C-17-AT presented in this thesis only accounts for mid-winter temperatures. However, these limited observations do imply that if CDOT is interested in removing an expansion joint, the bridge superstructure and retrofit option would need to support the movement of the bridge. The parametric study and data analysis of thermal gradients indicate a stark need for further research into thermal gradients experienced by bridges. Finally, the LCCA concluded that a retrofit continuous bridge design would provide the most cost effective design by decreasing joint replacement costs and pier cap corrosion
six interviews
UID/EAT/00693/2013Com o objetivo de analisar a presencĢ§a ou a auseĢncia de Ansiedade de Performance Musical (APM) em duos instrumentais con- solidados, seis entrevistas semiestruturadas com membros de treĢs duos instrumentais de muĢsica de caĢmara de longa duracĢ§aĢo (violino e piano; violoncelo e piano; piano a 4 maĢos) foram conduzidas. A anaĢlise mostrou que a APM eĢ um pouco comum a todos os muĢsicos, mas que a formacĢ§aĢo de duo foi considerada um lugar seguro ou de refuĢgio quando com- parado ao lugar da performance solo. As causas da APM na performance em duo, para os entrevistados, foram relacionadas aĢ famiĢlia e ao ambiente em que foram criados. AleĢm disso, a relutaĢncia em falar sobre APM entre os membros dos duos prevaleceu, e a falta de um sistema educacional para promover o conhecimento e auxiliar no desenvolvimento de estrateĢgias de enfrentamento foi observada. Diferentes atitudes foram observadas atraveĢs das diferencĢ§as de geracĢ§oĢes dos duos, no que diz respeito aĢ resolucĢ§aĢo do problema da APM. No entanto, todos concordaram que uma atitude psicossomaĢtica positiva e um estilo de vida saudaĢvel, juntamente com a aplicacĢ§aĢo das teĢcnicas de respiracĢ§aĢo e concentracĢ§aĢo, saĢo meios e eficazes para combater os problemas da APM. Em relacĢ§aĢo aĢs suas percepcĢ§oĢes de desempenho com o parceiro regular em um duo de longo prazo (āduo consolidadoā), em oposicĢ§aĢo a um parceiro ocasional em um duo de curto prazo (āduo ocasionalā), todos concordaram com a satisfacĢ§aĢo preferencial do duo de longo prazo, apreciando nele āoutra percepcĢ§aĢo, outra poesiaā.publishersversionpublishe
Cytological characterization and allelism testing of anther developmental mutants identified in a screen of maize male sterile lines.
Proper regulation of anther differentiation is crucial for producing functional pollen, and defects in or absence of any anther cell type result in male sterility. To deepen understanding of processes required to establish premeiotic cell fate and differentiation of somatic support cell layers a cytological screen of maize male-sterile mutants has been conducted which yielded 42 new mutants including 22 mutants with premeiotic cytological defects (increasing this class fivefold), 7 mutants with postmeiotic defects, and 13 mutants with irregular meiosis. Allelism tests with known and new mutants confirmed new alleles of four premeiotic developmental mutants, including two novel alleles of msca1 and single new alleles of ms32, ms8, and ocl4, and two alleles of the postmeiotic ms45. An allelic pair of newly described mutants was found. Premeiotic mutants are now classified into four categories: anther identity defects, abnormal anther structure, locular wall defects and premature degradation of cell layers, and/or microsporocyte collapse. The range of mutant phenotypic classes is discussed in comparison with developmental genetic investigation of anther development in rice and Arabidopsis to highlight similarities and differences between grasses and eudicots and within the grasses
Automated Crowdturfing Attacks and Defenses in Online Review Systems
Malicious crowdsourcing forums are gaining traction as sources of spreading
misinformation online, but are limited by the costs of hiring and managing
human workers. In this paper, we identify a new class of attacks that leverage
deep learning language models (Recurrent Neural Networks or RNNs) to automate
the generation of fake online reviews for products and services. Not only are
these attacks cheap and therefore more scalable, but they can control rate of
content output to eliminate the signature burstiness that makes crowdsourced
campaigns easy to detect.
Using Yelp reviews as an example platform, we show how a two phased review
generation and customization attack can produce reviews that are
indistinguishable by state-of-the-art statistical detectors. We conduct a
survey-based user study to show these reviews not only evade human detection,
but also score high on "usefulness" metrics by users. Finally, we develop novel
automated defenses against these attacks, by leveraging the lossy
transformation introduced by the RNN training and generation cycle. We consider
countermeasures against our mechanisms, show that they produce unattractive
cost-benefit tradeoffs for attackers, and that they can be further curtailed by
simple constraints imposed by online service providers
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