656 research outputs found
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Establishing Trustworthy Repositories of Scientific Data: Opportunities and Benefits
Scientific progress often depends on the ability of the scientific community to build on the works of others. Such works include scientific data, published reports of findings, and other research-related information and artifacts that are produced as part of the scientific process. Providing capabilities for accessing and using such scientific works enables the reproducibility of published methods and results to identify opportunities for improvement. Access and use of science products also enables others to build on previous work. In an increasingly digital world, the science community accesses and uses relevant scientific resources that have been obtained from digital repositories, data centers, and archives, as well as from traditional sources such as publishers of journal articles. Digital repositories need to establish capabilities, which provide access to and enable the use of digital resources. These resources are needed by the science community to improve and build o! n the efforts of others. Digital repositories that provide free and unrestricted access to scientific data and research-related information can reduce the barriers to science. By reducing these barriers they will be able to offer opportunities for members of the scientific community to pursue research questions and challenges that were previously unapproachable. These may include opportunities for researchers to gather data from other domains and support interdisciplinary research. Opportunities to use the data products and services offered by digital repositories also can contribute to the development of the scientific community and to the emergence of new areas of study
On complex surfaces diffeomorphic to rational surfaces
In this paper we prove that no complex surface of general type is
diffeomorphic to a rational surface, thereby completing the smooth
classification of rational surfaces and the proof of the Van de Ven conjecture
on the smooth invariance of Kodaira dimension.Comment: 34 pages, AMS-Te
Numerical solution to the hermitian Yang-Mills equation on the Fermat quintic
We develop an iterative method for finding solutions to the hermitian
Yang-Mills equation on stable holomorphic vector bundles, following ideas
recently developed by Donaldson. As illustrations, we construct numerically the
hermitian Einstein metrics on the tangent bundle and a rank three vector bundle
on P^2. In addition, we find a hermitian Yang-Mills connection on a stable rank
three vector bundle on the Fermat quintic.Comment: 25 pages, 2 figure
Two new \u3ci\u3eVaejovis\u3c/i\u3e C.L. Koch 1836 from highlands of the Sierra Madre Occidental, Durango, Mexico (Scorpiones, Vaejovidae)
Two new species of the mexicanus group of Vaejovis C.L. Koch are described from the Madrean pine-oak forests of the Sierra Madre Occidental in the state of Durango, Mexico. These species, Vaejovis sierrae sp. nov. and Vaejovis mcwesti sp. nov., are distinguished from each other and the only other species of the mexicanus group known from this mountain range, Vaejovis montanus Graham and Bryson, by morphometrics, carinal development of the pedipalps, granulation of the metasoma, and body size. A key to the species of the mexicanus group from the Sierra Madre Occidental is provided
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Computational Experience with Confidence Regions and Confidence Intervals for Nonlinear Least Squares ; CU-CS-302-85
Precision and manufacturing at the Lawrence Livermore National Laboratory
Precision Engineering is one of the Lawrence Livermore National Laboratory's core strengths. This paper discusses the past and present current technology transfer efforts of LLNL's Precision Engineering program and the Livermore Center for Advanced Manufacturing and Productivity (LCAMP). More than a year ago the Precision Machine Commercialization project embodied several successful methods of transferring high technology from the National Laboratories to industry. Currently, LCAMP has already demonstrated successful technology transfer and is involved in a broad spectrum of current programs. In addition, this paper discusses other technologies ripe for future transition including the Large Optics Diamond Turning Machine
Optimization and measurement of a smoothly profiled horn for a W-band gyro-TWA
In this paper, a smoothly profiled horn was designed and manufactured to replace a corrugated output horn for a W-band gyro-TWA with improved ultra-high vacuum compatibility. It was optimized for high vacuum integrity, low reflection, high fundamental Gaussian mode content, low side lobe levels and high directivity over the frequency bandwidth of 90 - 100 GHz. Over this operating frequency band the reflectivity was better than -37 dB and the coupling to a fundamental Gaussian mode was above 97%. The far field pattern showed a directivity of approximately 27 dB in the measurement with side lobes lower than -30 dB
A single-particle characterization of a mobile Versatile Aerosol Concentration Enrichment System for exposure studies
BACKGROUND: An Aerosol Time-of-Flight Mass Spectrometer (ATOFMS) was used to investigate the size and chemical composition of fine concentrated ambient particles (CAPs) in the size range 0.2â2.6 ÎŒm produced by a Versatile Aerosol Concentration Enrichment System (VACES) contained within the Mobile Ambient Particle Concentrator Exposure Laboratory (MAPCEL). The data were collected during a study of human exposure to CAPs, in Edinburgh (UK), in February-March 2004. The air flow prior to, and post, concentration in the VACES was sampled in turn into the ATOFMS, which provides simultaneous size and positive and negative mass spectral data on individual fine particles. RESULTS: The particle size distribution was unaltered by the concentrator over the size range 0.2â2.6 ÎŒm, with an average enrichment factor during this study of ~5 (after dilution of the final air stream). The mass spectra from single particles were objectively grouped into 20 clusters using the multivariate K-means algorithm and then further grouped manually, according to similarity in composition and time sequence, into 8 main clusters. The particle ensemble was dominated by pure and reacted sea salt and other coarse inorganic dusts (as a consequence of the prevailing maritime-source climatology during the study), with relatively minor contributions from carbonaceous and secondary material. Very minor variations in particle composition were noted pre- and post-particle concentration, but overall there was no evidence of any significant change in particle composition. CONCLUSION: These results confirm, via single particle analysis, the preservation of the size distribution and chemical composition of fine ambient PM in the size range 0.2â2.6 ÎŒm after passage through the VACES concentration instrumentation
Numerical Hermitian Yang-Mills Connections and Vector Bundle Stability in Heterotic Theories
A numerical algorithm is presented for explicitly computing the gauge
connection on slope-stable holomorphic vector bundles on Calabi-Yau manifolds.
To illustrate this algorithm, we calculate the connections on stable monad
bundles defined on the K3 twofold and Quintic threefold. An error measure is
introduced to determine how closely our algorithmic connection approximates a
solution to the Hermitian Yang-Mills equations. We then extend our results by
investigating the behavior of non slope-stable bundles. In a variety of
examples, it is shown that the failure of these bundles to satisfy the
Hermitian Yang-Mills equations, including field-strength singularities, can be
accurately reproduced numerically. These results make it possible to
numerically determine whether or not a vector bundle is slope-stable, thus
providing an important new tool in the exploration of heterotic vacua.Comment: 52 pages, 15 figures. LaTex formatting of figures corrected in
version 2
Stakeholder Theory and Marketing: Moving from a Firm-Centric to a Societal Perspective
This essay is inspired by the ideas and research examined in the special section on âStakeholder Marketingâ of the Journal of Public Policy & Marketing in 2010. The authors argue that stakeholder marketing is slowly coalescing with the broader thinking that has occurred in the stakeholder management and ethics literature streams during the past quarter century. However, the predominant view of stakeholders that many marketers advocate is still primarily pragmatic and company centric. The position advanced herein is that stronger forms of stakeholder marketing that reflect more normative, macro/societal, and network-focused orientations are necessary. The authors briefly explain and justify these characteristics in the context of the growing âprosocietyâ and âproenvironmentâ perspectivesâorientations that are also in keeping with the public policy focus of this journal. Under the âhard formâ of stakeholder theory, which the authors endorse, marketing managers must realize that serving stakeholders sometimes requires sacrificing maximum profits to mitigate outcomes that would inflict major damage on other stakeholders, especially society
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