Noise generation by turbulence-propeller interaction in asymmetric flow

AbstractThis paper is concerned with a particular source of both broadband and tonal aeroengine noise, termed unsteady distortion noise. This noise arises from the interaction between turbulent eddies, which occur naturally in the atmosphere or are shed from the fuselage, and the rotor. This interaction produces broadband noise across a broad frequency spectrum. In cases in which there is strong streamtube contraction, which is especially true for open rotors at low-speed conditions (such as at take-off or for static testing), tonal noise at frequencies equal to multiples of the blade passing frequency are also produced, owing to the enhanced axial coherence caused by eddy stretching. In a previous paper (Majumdar & Peake, J. Fluid Mech., vol. 359, 1998, pp. 181–216), a model for unsteady distortion noise was developed in axisymmetric flow. However, asymmetric situations are also of much interest, and in this paper we consider two cases of asymmetric distortion: firstly that induced by the proximity of a second rotor, and secondly that caused by non-zero inclination to the flight direction, as found at take-off. This requires significant extension of the previous axisymmetric analysis. We find that the introduction of asymmetric flow features can have a significant decibel effect on the radiated sound power. For instance, in low-speed conditions we find that the tonal level is reduced significantly by the proximity of a second rotor, compared to the axisymmetric case, while the effect on the broadband levels is rather modest.RAVR acknowledges funding from an EPSRC Rolls Royce CASE award which made this work possible.This is the author accepted manuscript. The final version is available from Cambridge University Press via http://dx.doi.org/10.1017/jfm.2014.48

A cellular automaton framework for within-field vineyard variance and grape production simulation

Winegrowers for generations know it all too well that grapes harvested from different areas within a vineyard will produce wines of different flavours, mainly due to within-field variance in vine vigour caused by environmental variability from various factors, such as soil properties, microclimate conditions, and rootstock. Recent research attempts on the use of state-of-the-art technologies to model/ simulate within-field variance at a vineyard scale are outlined. Consequently, the paper illustrates a cellular automaton (CA) framework being developed for simulating the within-field variance in grapevine plant vigour, phenological events and vineyard production using random or real thematic mappings of likely key factors that contribute to the observed variance. The CA approach provides an alternative software tool to conventional crop estimation methods that are dependent upon expensive yield sampling methods

Do disagreeable political discussion networks undermine attitude strength?

How attitudes change and affect behavior depends, in large part, on their strength. Strong attitudes are more resistant to persuasion and are more likely to produce attitude-consistent behavior. But what influences attitude strength? In this paper, we explore a widely discussed, but rarely investigated, factor: an individual’s political discussion network. What prior work exists offers a somewhat mixed picture, finding sometimes that disagreeable networks weaken attitudes and other times that they strengthen attitudes. We use a novel national representative dataset to explore the relationship between disagreeable networks and attitude strength. We find, perhaps surprisingly, no evidence that disagreements in networks affect political attitude strength. We conclude by discussing likely reasons for our findings, which, in turn, provide a research agenda for the study of networks and attitude strength

CC204 Revised 1969 Weed Control in Sugar Beets

Campaign Circular 204 Revised 1969 discusses weed control in sugar beets

An Audit of Political Behavior Research

What are the most important concepts in the political behavior literature? Have experiments supplanted surveys as the dominant method in political behavior research? What role does the American National Election Studies (ANES) play in this literature? We utilize a content analysis of over 1,100 quantitative articles on American mass political behavior published between 1980 and 2009 to address these questions. We then supplement this with a second sample of articles published between 2010 and 2018. Four key takeaways are apparent. First, the agenda of this literature is heavily skewed toward understanding voting to a relative lack of attention to specific policy attitudes and other topics. Second, experiments are ascendant, but are far from displacing surveys, and particularly the ANES. Third, while important changes to this agenda have occurred over time, it remains much the same in 2018 as it was in 1980. Fourth, the centrality of the ANES seems to stem from its time-series component. In the end, we conclude that the ANES is a critical investment for the scientific community and a main driver of political behavior research

Probabilistic Clustering of Sequences: Inferring new bacterial regulons by comparative genomics

Genome wide comparisons between enteric bacteria yield large sets of conserved putative regulatory sites on a gene by gene basis that need to be clustered into regulons. Using the assumption that regulatory sites can be represented as samples from weight matrices we derive a unique probability distribution for assignments of sites into clusters. Our algorithm, 'PROCSE' (probabilistic clustering of sequences), uses Monte-Carlo sampling of this distribution to partition and align thousands of short DNA sequences into clusters. The algorithm internally determines the number of clusters from the data, and assigns significance to the resulting clusters. We place theoretical limits on the ability of any algorithm to correctly cluster sequences drawn from weight matrices (WMs) when these WMs are unknown. Our analysis suggests that the set of all putative sites for a single genome (e.g. E. coli) is largely inadequate for clustering. When sites from different genomes are combined and all the homologous sites from the various species are used as a block, clustering becomes feasible. We predict 50-100 new regulons as well as many new members of existing regulons, potentially doubling the number of known regulatory sites in E. coli.Comment: 27 pages including 9 figures and 3 table

Stroke impact on mortality and psychologic morbidity within the Childhood Cancer Survivor Study.

BackgroundPoor socioeconomic and health-related quality of life (HRQOL) outcomes in survivors of childhood cancer can lead to distress and overall negatively impact the lives of these individuals. The current report has highlighted the impact of stroke and stroke recurrence on mortality, psychological HRQOL, and socioeconomic outcomes within the Childhood Cancer Survivor Study (CCSS).MethodsThe CCSS is a retrospective cohort study with longitudinal follow-up concerning survivors of pediatric cancer who were diagnosed between 1970 and 1986. Mortality rates per 100 person-years were calculated across 3 periods: 1) prior to stroke; 2) after first stroke and before recurrent stroke; and 3) after recurrent stroke. Socioeconomic outcomes, the standardized Brief Symptoms Inventory-18, the Medical Outcomes Study 36-Item Short Form Health Survey, and the CCSS-Neurocognitive Questionnaire also were assessed.ResultsAmong 14,358 participants (median age, 39.7 years), 224 had a stroke after their cancer diagnosis (single stroke in 161 patients and recurrent stroke in 63 patients). Based on 2636 deaths, all-cause late mortality rates were 0.70 (95% CI, 0.68-0.73) prior to stroke, 1.03 (95% CI, 0.73-1.46) after the first stroke, and 2.42 (95% CI, 1.48-3.94) after the recurrent stroke. Among 7304 survivors, those with stroke were more likely to live with a caregiver (single stroke odds ratio [OR], 2.3 [95% CI, 1.4-3.8]; and recurrent stroke OR, 5.3 [95% CI, 1.7-16.8]) compared with stroke-free survivors. Stroke negatively impacted task efficiency (single stroke OR, 2.4 [95% CI, 1.4-4.1] and recurrent stroke OR, 3.3 [95% CI, 1.1-10.3]) and memory (single stroke OR, 2.1 [95% CI, 1.2-3.7]; and recurrent stroke OR, 3.5 [95% CI, 1.1-10.5]).ConclusionsStroke and stroke recurrence are associated with increased mortality and negatively impact HRQOL measures in survivors of pediatric cancer

DB-PABP: a database of polyanion-binding proteins

The interactions between polyanions (PAs) and polyanion-binding proteins (PABPs) have been found to play significant roles in many essential biological processes including intracellular organization, transport and protein folding. Furthermore, many neurodegenerative disease-related proteins are PABPs. Thus, a better understanding of PA/PABP interactions may not only enhance our understandings of biological systems but also provide new clues to these deadly diseases. The literature in this field is widely scattered, suggesting the need for a comprehensive and searchable database of PABPs. The DB-PABP is a comprehensive, manually curated and searchable database of experimentally characterized PABPs. It is freely available and can be accessed online at http://pabp.bcf.ku.edu/DB_PABP/. The DB-PABP was implemented as a MySQL relational database. An interactive web interface was created using Java Server Pages (JSP). The search page of the database is organized into a main search form and a section for utilities. The main search form enables custom searches via four menus: protein names, polyanion names, the source species of the proteins and the methods used to discover the interactions. Available utilities include a commonality matrix, a function of listing PABPs by the number of interacting polyanions and a string search for author surnames. The DB-PABP is maintained at the University of Kansas. We encourage users to provide feedback and submit new data and references