25,544 research outputs found
Interface concerns of ejector integration in V/STOL aircraft
A number of areas which have in the past contributed to weight, complexity, and thrust losses in the ejector-powered V/STOL vehicle were identified. Most of these interfaces taken singly do not represent a severe compromise to the vehicle; however, the bottom line is that the sum of compromises and the subsequent effects on performance, flight operations and maintenance have rendered the ejector V/STOL aircraft unattractive. In addition to some of the unique ejector/aircraft integration problems, the vehicle by virtue of having a V/STOL capability, is compromised in other areas. To be successful and acceptable, the advantages must outweight the disadvantages and simplicity with minimum penalties must be the rule. It is concluded that more emphasis must be placed on the ejector/aircraft interface for the concept to be successful
I Don\u27t Care If I Ever Get Back: Marathons Lasting 20 or More Innings
This article looks at marathon games of baseball. For purposes of this article, a marathon is defined as a game lasting 20 or more innings. In my research I have discovered 341 marathons. These games are hard to find. Leagues either keep no records, or keep track only of their longest game; only the Texas League keeps records on all marathons. Nobody has ever before explored such questions as: What is the probability a game will go x number of innings? How often should we expect a marathon of 20 or more innings, or 40 or more innings? What is the probability the 26-inning major league record will be broken this year? Which is “rarer,” the 26-inning major league record, 33-inning minor league record, or 45-inning “other” category record? In this article we’ll answer these questions
Quasigeometric Distributions and Extra Inning Baseball Games
Each July, the eyes of baseball fans across the country turn to Major League Baseball’s All-Star Game, gathering the best and most popular players from baseball’s two leagues to play against each other in a single game. In most sports, the All-Star Game is an exhibition played purely for entertainment. Since 2003, the baseball All-Star Game has actually ‘counted’, because the winning league gets home field advantage in the World Series. Just one year before this rule went into effect, there was no winner in the All-Star Game, as both teams ran out of pitchers in the 11th inning and the game had to be stopped at that point. Under the new rules, the All-Star Game must be played until there is a winner, no matter how long it takes, so the managers need to consider the possibility of a long extra inning game. This should lead the managers to ask themselves what the probability is that the game will last 12 innings. What about 20 innings? Longer?
In this paper, we address these questions and several other questions related to the game of baseball. Our methods use a variation on the well-studied geometric distribution called the quasigeometric distribution. We begin by reviewing some of the literature on applications of mathematics to baseball. In the second section we will define the quasigeometric distribution and examine several of its properties. The final two sections examine the applications of this distribution to models of scoring patterns in baseball games and, more specifically, the length of extra inning games
Electron beam X-Y deflection system Final report
Design and fabrication of electron beam X-Y deflection system for retrofit on welding gun
Integrated optical directional coupler biosensor
We present measurements on biomolecular binding reactions, using a new type of integrated optical biosensor based on a planar directional coupler structure. The device is fabricated by Ag+-Na+ ion-exchange in glass and definition of the sensing region is achieved by use of transparent fluoropolymer isolation layers formed by thermal evaporation. The suitability of the sensor for application to the detection of environmental pollutants is considered
Sensing and control in dual-recycling laser interferometer gravitational-wave detectors
We introduce length-sensing and control schemes for the dual-recycled cavity-enhanced Michelson interferometer configuration proposed for the Advanced Laser Interferometer Gravitational Wave Observatory (LIGO). We discuss the principles of this scheme and show methods that allow sensing and control signals to be derived. Experimental verification was carried out in three benchtop experiments that are introduced. We present the implications of the results from these experiments for Advanced LIGO and other future interferometric gravitational-wave detectors
Natural variation in abiotic stress responsive gene expression and local adaptation to climate in Arabidopsis thaliana.
Gene expression varies widely in natural populations, yet the proximate and ultimate causes of this variation are poorly known. Understanding how variation in gene expression affects abiotic stress tolerance, fitness, and adaptation is central to the field of evolutionary genetics. We tested the hypothesis that genes with natural genetic variation in their expression responses to abiotic stress are likely to be involved in local adaptation to climate in Arabidopsis thaliana. Specifically, we compared genes with consistent expression responses to environmental stress (expression stress responsive, "eSR") to genes with genetically variable responses to abiotic stress (expression genotype-by-environment interaction, "eGEI"). We found that on average genes that exhibited eGEI in response to drought or cold had greater polymorphism in promoter regions and stronger associations with climate than those of eSR genes or genomic controls. We also found that transcription factor binding sites known to respond to environmental stressors, especially abscisic acid responsive elements, showed significantly higher polymorphism in drought eGEI genes in comparison to eSR genes. By contrast, eSR genes tended to exhibit relatively greater pairwise haplotype sharing, lower promoter diversity, and fewer nonsynonymous polymorphisms, suggesting purifying selection or selective sweeps. Our results indicate that cis-regulatory evolution and genetic variation in stress responsive gene expression may be important mechanisms of local adaptation to climatic selective gradients
Creating a Culture of Security in the University of Maryland Libraries
Citation: Lowry, Charles B. and Lori A. Goetsch, “Creating a Culture of Security in the University of Maryland Libraries,” portal: Libraries and the Academy, 1(4):455-464, October 2001.A critical part of building a shared culture of mutual responsibility for security and safety is a thorough understanding of all the elements of a library’s security environment. To address the need for a more coherent approach to library safety and security that reinforces a philosophy of shared responsibility among all staff, the University of Maryland Libraries embarked upon an assessment of policies, procedures, and facilities in partnership with the Association of Research Libraries. Begun in the fall of 1997, the security study and subsequent development of practice and policy were implemented over a two-year period and serve as a model comprehensive approach for a large academic library system
Incidence, correlates, and origins of dioecy in the Island Flora of New Caledonia
Premise of research. Because it is an inherently risky sexual system, dioecy is globally rare. Attempts to explain unusually high incidences of dioecy on certain islands have generated a considerable literature on the relationships among dioecy, its ecological correlates, establishment after transoceanic dispersal, and postdispersal speciation. Nevertheless, few studies of dioecy on islands have included considerations of the origins and maintenance of dioecy on islands along with determinations of its incidence. Methodology. We used the literature, herbarium specimens, and fieldwork to determine the incidence of dioecy in the native angiosperm flora of New Caledonia. We inferred the number and characteristics of colonists needed to account for the extant dioecious flora. We made traditional species-based numerical assessments of associations between dioecy on New Caledonia and woodiness, plain flowers, fleshy fruit, habitat, and endemism, and we constructed a phylogenetic tree for New Caledonia's native angiosperms to investigate correlated evolution of dioecy and those associated traits. Pivotal results. This study is the first comprehensive survey of sexual systems for the flora of New Caledonia. One-fifth of New Caledonia's native angiosperms are dioecious. Dioecy is numerically overrepresented among species that are woody, have plain flowers, have fleshy fruit, occur in rainforest, or are endemic. However, we found strong evidence for correlated evolution only for dioecy and woodiness, plain flowers, and fleshy fruit. Dioecious groups with more of the widely accepted morphological correlates of dioecy tend to be more speciose. Approximately 90% of the colonists that gave rise to the extant dioecious flora were themselves dioecious. Approximately 60% of the colonists have two or more dioecious descendants, and those descendants comprise more than 90% of the extant dioecious species. Conclusions. Successful dispersal and establishment of already dioecious colonists and autochthonous speciation of dioecious lineages are primarily responsible for the high incidence of dioecy on New Caledonia. There were relatively few postdispersal transitions to dioecy. The associations of dioecy with woodiness, plain flowers, and fleshy fruit result from correlated evolution that occurred prior to dispersal to New Caledonia, while the associations of dioecy with rainforest habitat and endemism appear to result from autochthonous speciation of dioecious lineages. With similar to similar to 4% of the world's dioecious species occurring only there, New Caledonia should be a rich source of new information on the evolutionary ecology of dioecy. Realization of this potential will require both further study and concerted efforts to preserve the native flora
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