638,005 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Notes in Field: MTA from Harvard Sq to Washington St. Elevated from Winter St. to Northampton.
No full textNotes on a field trip from Boston City Hospital to Old North Church, by foot,
Monday, 25 June, conducted as part of the Perceptual Form of the City, a research
project investigating the individual’s perception of the urban landscape
Andrew Field papers
No full textAndrew Field (1938- ) is a scholar, translator, and author, who has published translations of Russian literature, critical studies, biographies, fiction, essays, and travel articles. He holds degrees from Columbia University as well as a Ph.D. from the University of Queensland, Brisbane, Australia. From 1977 to 1979, he was a professor at Griffith University, Brisbane, Australia. Dr. Field's papers consist of materials relating to the writing of his 1983 study of the life and work of Djuna Barnes, Djuna: the Formidable Miss Barnes (alternately entitled Djuna: The Life and Times of Djuna Barnes). Included in the collection are correspondence, manuscripts, research notes, clippings related to the book's publication and reception, and photographs. Also included is a handwritten manuscript of a poem by Barnes
Turbulent MHD channel flows under streamwise magnetic field
No full textA streamwise magnetic field leads to turbulent drag reduction in channel flow of a conducting liquid due to the selective Joule damping of certain flow structures. Near the walls, the turbulent mean velocity profile retains the logarithmic layer but the von Karman constant decreases with increasing magnetic field strength. In the outer region, the flow is characterized by persistent streaky structures of large streamwise extent, which lead to a rather flat mean velocity profile. In addition, the streamwise velocity fluctuations develop a pronounced second peak upon increasing the magnetic induction as well as a second logarithmic layer that increases in steepness
DNS of natural convection in liquid metal with srtong magnetic field in retangular box
No full textDirect numerical simulations of natural convection in liquid metal within rectangular box heated uniformly from below with uniform strong vertical magnetic field are conducted. The main aim is to explore the possibilities and mechanisms of convection instabilities in such flows. The effects of parameter range on the flow structure, i.e. variations in Hartmann number, Rayleigh number and aspect ratio, are analyzed. It is shown that the magnetic field can completely change the structure and orientation of convection rolls by leading a new flow structure lined magnetic field. And if the magnetic field is strong enough, convection in the system can be fully suppressed
Vitamin D Testing Practices in Collegiate Cross Country and Track and Field Athletes
No full textVitamin D insufficiency and deficiency has become problematic within the global population. Low levels of Vitamin D may have significant impacts on bone health and the musculoskeletal system, key factors in athletic performance. Recently, Vitamin D testing has gained popularity amongst athletic populations, but there is little research in cross country and track and field (XC and TF) collegiate athletes. The purpose of this study was to investigate the Vitamin D testing practices of NCAA sponsored XC and TF programs. Fifty-five Certified Athletic Trainers (ATs) participated in the study (43 XC and TF ATs, 12 non-XC and TF ATs). The responses of XC and TF ATs were analyzed separately and compared by region of the U.S. and NCAA Division classification. Few participants (6/30) identified their institution as having a Vitamin D testing policy in place. The six participants indicated that red flags and health history are the primary indications for Vitamin D testing while preventative screening occurs at half of the Division I institutions. There was little consensus regarding adequate Vitamin D levels and number of Vitamin D tests per year. Although, 70.6% of Division I XC and TF ATs support Vitamin D testing in their athletes while 66.7% of Divisions II and III ATs did not. In addition to testing practices, this study gathered data regarding indoor training duration and bone stress injuries for XC and TF collegiate athletes. There was no significant association between indoor training duration and region of the U.S. for XC athletes, however, there was a statistically significant association for TF athletes (p = 0.016, 0.050). Using the injury data provided, an injury incidence and frequency was calculated of which women’s XC had the highest rates (11.9, 14.1), followed by women’s TF (6.3, 9.2), men’s XC (5.4, 7.6), and men’s TF (4.1, 4.9). A major limitation of the present study was the small sample size, however, future research utilizing an increased sample size may produce different or more statistically significant results. Overall, continued education and research regarding the importance of Vitamin D and athletic performance is necessary to create universal testing policies in collegiate athletics
Design, Construction and Deployment of a Compact, Robust Field Data Acquisition System for Structural Field Monitoring
No full textThe portable field data acquisition system consists of four components: datalogger, Wheatstone bridges, multiplexers, and portable computer. The data acquisition system fulfills the role of a portable, self-powered measurement device necessary for structural field monitoring and will also serve as a measurement platform for future field tests conducted by the University of Pittsburgh.To better illustrate the capabilities of the field data acquisition system, an application is illustrated using the Boyer Bridge research project in Butler County.The Boyer Bridge over the Slippery Rock Creek in PennDOT Engineering District 10-0 has recently received a new fiber-reinforced polymer deck as part of an overall bridge replacement project. In order to quantify the composite action of the deck, effective width factor and live load distribution factors, the Boyer Bridge is instrumented with thirty strain gages and monitored with the portable field data acquisition system.Field-testing of the Boyer Bridge over the Slippery Rock Creek in PennDOT Engineering District 10-0 consists of static loads applied by a test vehicle to the deck and measuring strain responses. To date, two field tests have been performed on the Boyer Bridge. An examination of each stringer's strain profile from the CR23x datalogger reveals a very close agreement to expected behavior. From multiple tests performed at the same load position, it is evident that the CR23x's strain measurements exhibit excellent repeatability, while verification tests performed in the laboratory show good linearity
Notes in Field - Functional Trip
No full textNotes on a trip from Massachusetts General Hospital to South Station as quickly as possible. These notes were collected as part of the Perceptual Form of the City, a research project investigating the individual’s perception of the urban landscape
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
EXPLAINING PATTERNS OF DOMINANCE IN OLD-FIELD COMMUNITIES: TRADE-OFFS, FEEDBACKS, MUTUALISMS AND ENEMIES
No full textAlthough one of the oldest observations within ecology is that within communities there are few common species with many uncommon and rare species, the mechanisms that shape this relationship remain elusive. The primary explanations for repeated dominance in plant communities lie in competition theory, which predicts specific allocation to resource acquisition, low resource tolerance, colonization, and herbivore tolerance and resistance. Alternatively, soil
community feedback theory predicts positive plant-soil feedbacks to alter competitive dynamics and lead to dominance. Finally, specific mutualistic clades of the soil community, such as mycorrhizal fungi, may increase resource acquisition or herbivore tolerance, thus promoting positive feedback. To address these mechanisms that contribute to relative abundance and dominance, I used a light limited, old-field model system. Although these systems are relatively diverse, there is a striking pattern of repeated dominance by Solidago canadensis. By using a series of greenhouse and manipulative, long-term in situ experiments, I found no “smoking gun” mechanism to explain the dominance of So. canadensis, but rather an entire suite of processes
that likely contribute to relative abundance and the maintenance of diversity. I found no evidence of life history trade-offs across old-field species, with S. canadensis consistently violating long-standing theory by being the best light competitor, most shade tolerant, most
herbivore resistant, most herbivore tolerant, and among the fastest growing species. Looking belowground, I found that old-field plant species, even coexisting congeneric species, culture significantly different soil microbial communities, which altered plant performance, changed the
intensity of interspecific competition and reversed whether plant species were limited by conspecifics or heterospecifics. Although this mosaic of shifting competitive abilities due to soil feedbacks is predicted to maintain diversity, the ability of S. canadensis to grow well in its own and competitor soil communities may foster S. canadensis invasion and subsequent defense of territory. Finally, mycorrhizal fungi increased herbivore tolerance across old-field species, while having little or negative effects on plants in the absence of herbivory. This process may promote diversity within old-fields, but offers insight into how So. canadensis maintain dominance in the face of dozens of specialist herbivores
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