218 research outputs found
The General Circulation of the Tropical Atmosphere and Climate Changes
No full textI examine the general circulation of the tropical atmosphere and climate changes. First, the response of the zonal surface temperature gradients and zonally asymmetric tropical overturning circulations (Walker circulations) to substantial changes in the longwave optical depth of the atmosphere in an idealized general circulation model (GCM) is compared with scaling theories. Second, the response of the hydrological cycle and monsoonal Hadley circulations to changes in top-of-atmosphere insolation associated with orbital precession is examined in an idealized GCM.
Zonal surface temperature gradients and Walker circulations are examined over a wide range of climates simulated by varying the optical thickness in an idealized atmospheric GCM with a climate-invariant zonally asymmetric ocean energy flux. The tropical zonal surface temperature gradient and Walker circulation generally decrease as the climate warms in the GCM simulations. A scaling relationship based on a two-term balance in the surface energy budget accounts for the changes in the zonally asymmetric component of the GCM-simulated surface temperature gradients. A scaling estimate for the Walker circulation based on differential changes (precipitation rates and saturation specific humidity) in the hydrological cycle accounts for the GCM simulations provided locally averaged quantities are used in the estimate.
The results of atmospheric GCM simulations with varied top-of-atmosphere insolation are analyzed to constrain orbitally-forced changes in the tropical atmospheric circulations and precipitation. When the perihelion is varied between solstices, there is more annual-mean precipitation in the hemisphere in which perihelion occurs during the summer solstice. In aquaplanet simulations, this is primarily associated with thermodynamic changes: there is a correlation between the seasonal cycle of the perturbed water vapor and the seasonal cycle of the Hadley circulation convergence. The monsoonal Hadley circulation does not respond to insolation gradients in a simple manner, as the atmosphere’s energy stratification changes. An idealized continent that has a simple treatment of land surface hydrology and inhomogeneous heat capacity allows an assessment of how land-sea contrasts can mediate the response to orbital precession. In these simulations, the response of precipitation to orbital precession depends on changes in the atmospheric circulation, which strengthens when perihelion occurs in the summer of the hemisphere with the land region. The changes in atmospheric circulation are related to changes in both the top-of-atmosphere energy balance and the thermodynamic properties of the surface.</p
Uncertainty and the price for crude oil reserves
No full textInnovations in futures, options, and derivative instruments permit active trading, speculating and hedging - linking markets for physical petroleum products with financial markets. These derivative markets continuously value petroleum delivered today and for future dates, providing a market price for inventories. Underground petroleum reserves are also an inventory defined by exploration surveys and development drilling. Thus, observable market information can be used to value these reserves. Option - valuation models can be used to price reserves using observable markets, but are dependent on unexplained convenience yields revealed by the term structure of futures prices. The authors apply a general inventory pricing model to petroleum inventories and generate an empirical model of the returns to storage for petroleum markets. They examine the determinants of the crude oil convenience yield using a stochastic control model. They specify optimal production and inventory conditions using a third-order cost function and estimate them using monthly observations. Their inventory arbitrage condition embodies the Hotelling principle and Kaldor's convenience yield, and includes a premium on the dispersion in crude oil prices. The empirical results suggest that returns to storage contain both a cost-reducing component and often sizable premiums associated with the dispersion of petroleum prices. Their findings suggest that crude oil markets differentiated by quality and location provide similar premiums. The premiums associated with the dispersion of petroleum prices may account for persistent backwardation in crude oil prices. This finding may also explain the wide discrepancies between Hotelling values and transaction prices found in previous studies.Economic Theory&Research,Environmental Economics&Policies,Markets and Market Access,Labor Policies,Payment Systems&Infrastructure,Oil Refining&Gas Industry,Environmental Economics&Policies,Access to Markets,Markets and Market Access,Economic Theory&Research
Decentering the Dancing Text: From Dance Intertext to Hypertext
No full textThis paper explains and draws together two projects from different disciplines: dance studies and hypertext writing. Each project sets out to examine the processes and practices of hypertextuality, and to develop new ways of writing using electronic technology and the Internet. The dance studies project seeks to link the critical theory of intertextuality (as a means of dance interpretation) with the theoretical and practical concerns of hypertextuality. It hopes to show a convergence of the two into a working system for analysing dance in a network of people, institutions and information. The Associative Writing Framework (AWF) project seeks to explore how writers could best be supported in representing and exploring hypertextuality in a Web environment, and in producing new hypertexts which integrate or 'glue together' existing Web resources (ideas, concepts, data, descriptions, experiences, claims, theories, suggestions, reports, etc). Following the combining of the two projects we report on some initial evaluation of the AWF system by dance experts, and discuss where the relationship might lead and potential future outcomes of the collaboration
The Optical Corrector for the Dark Energy Spectroscopic Instrument
No full textMiller, Timothy N. et al.-- Full list of authors: Miller, Timothy N.; Doel, Peter; Gutierrez, Gaston; Besuner, Robert; Brooks, David; Gallo, Giuseppe; Heetderks, Henry; Jelinsky, Patrick; Kent, Stephen M.; Lampton, Michael; Levi, Michael E.; Liang, Ming; Meisner, Aaron; Sholl, Michael J.; Silber, Joseph Harry; Sprayberry, David; Aguilar, Jessica Nicole; de la Macorra, Axel; Eisenstein, Daniel; Fanning, Kevin; Font-Ribera, Andreu; Gaztañaga, Enrique; Gontcho A Gontcho, Satya; Honscheid, Klaus; Jimenez, Jorge; Joyce, Dick; Kehoe, Robert; Kisner, Theodore; Kremin, Anthony; Landriau, Martin; Le Guillou, Laurent; Magneville, Christophe; Martini, Paul; Miquel, Ramon; Moustakas, John; Nie, Jundan; Percival, Will; Poppett, Claire; Prada, Francisco; Rossi, Graziano; Schlegel, David; Schubnell, Michael; Seo, Hee-Jong; Sharples, Ray; Tarlé, Gregory; Vargas-Magaña, Mariana; Zhou, Zhimin; the DESI CollaborationThe Dark Energy Spectroscopic Instrument (DESI) is currently measuring the spectra of 40 million galaxies and quasars, the largest such survey ever made to probe the nature of cosmological dark energy. The 4 m Mayall telescope at Kitt Peak National Observatory has been adapted for DESI, including the construction of a 3°.2 diameter prime focus corrector that focuses astronomical light onto a 0.8 m diameter focal surface with excellent image quality over the DESI bandpass of 360–980 nm. The wide-field corrector includes six lenses, as large as 1.1 m in diameter and as heavy as 237 kilograms, including two counterrotating wedged lenses that correct for atmospheric dispersion over zenith angles from 0° to 60°. The lenses, cells, and barrel assembly all meet precise alignment tolerances on the order of tens of microns. The barrel alignment is maintained throughout a range of observing angles and temperature excursions in the Mayall dome by use of a hexapod, which is itself supported by a new cage, ring, and truss structure. In this paper we describe the design, fabrication, and performance of the new corrector and associated structure, focusing on how they meet DESI requirements. In particular, we describe the prescription and specifications of the lenses, design choices and error budgeting of the barrel assembly, stray light mitigations, and integration and test at the Mayall telescope. We conclude with some validation highlights that demonstrate the successful corrector on-sky performance, and we list some lessons learned during the multiyear fabrication phase. © 2024. The Author(s).The DESI Collaboration acknowledges the many insightful and creative contributions of the author Michael Lampton and mourns his passing.
The authors wish to thank Marty Valente and Jim Burge (Arizona Optical Systems), David Anderson and Vilma Anderson (Rayleigh Optical Corporation), and George Gardopee and Andrew Clarkson (L3 Brashear) for their helpful review of the lens polishing sections. We also wish to thank Dr. Charles Kennemore III (Viavi Solutions) for his extensive documentation of the coating work that supported this paper.
The DESI Collaboration appreciates Trish Dobson and American Cargoservice Inc. for managing the extensive logistics required to transport the corrector barrel sections safely from the United Kingdom to Kitt Peak by air and truck.
The authors acknowledge the support of the Gordon and Betty Moore Foundation, grant No. 3581, and the Heising-Simons Foundation, grant No. 2014-91, for their help in procuring long-lead components that enabled the corrector to meet its schedule.
Authors P.D. and D.B. acknowledge the support of the UK Science and Technology Facilities Council (STFC), grant No. ST/M00287X/1. The FNAL authors acknowledge support from Fermi Research Alliance, LLC (FRA), acting under contract No. DE-AC02-07CH11359 with the US Department of Energy.
This material is based on work supported by the US Department of Energy (DOE), Office of Science, Office of High-Energy Physics, under contract No. DE-AC02-05CH11231, and by the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility, under the same contract. Additional support for DESI was provided by the US National Science Foundation (NSF), Division of Astronomical Sciences, under contract No. AST-0950945 to the NSF's National Optical-Infrared Astronomy Research Laboratory; the Science and Technologies Facilities Council of the United Kingdom; the Gordon and Betty Moore Foundation; the Heising-Simons Foundation; the French Alternative Energies and Atomic Energy Commission (CEA); the National Council of Humanities, Science and Technology of Mexico (CONAHCYT); the Ministry of Science and Innovation of Spain (MICINN); and the DESI Member Institutions: https://www.desi.lbl.gov/collaborating-institutions. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the US National Science Foundation, the US Department of Energy, or any of the listed funding agencies.
The authors are honored to be permitted to conduct scientific research on Iolkam Du'ag (Kitt Peak), a mountain with particular significance to the Tohono O'odham Nation.
For more information, visit https://desi.lbl.gov.
Facility: Mayall (DESI)
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Current Views on Teacher Word Choice in American College Flute Lessons
No full textThe purpose of this study is to explore the factors that influence a teacher’s word choice in American private college-level flute lessons. Most of the research that has been conducted on music instruction focuses on technical methods for the purpose of enhancing curricula. Some research exists which explores the more psychological side of teaching and learning; however, the research that studies the private music lesson often seeks to understand either the teacher-student relationship through the eyes of students, or to understand music teacher perceptions on the ways in which their teaching informs their performing. While many studies and publications indirectly speak to the use of language in teaching and learning music, most research that explores the effectiveness of teaching approaches for specific techniques does not explore the verbal delivery used in the method. There is little literature in print which addresses teacher word choice, and even less, still, in the flute world. An examination of the available literature on subjects relevant to the factors that influence teacher word choice revealed six major topics: artist-teacher background, teacher’s responsibility to meet student’s needs and expectations, significance of the one-to-one teacher-student relationship, verbal teacher feedback, heightened sensitivities in music instruction, and words and music learning. Careful review of the prose relating word choice and existing practices in music instruction today led the author to pose the following research questions: 1. What elements of a teacher’s background influence their word choice in lessons? 2. To what degree does student individuality affect a teacher’s word choice from student to student? 3. How do teachers reflect their goals and values in their word choice? The research questions were addressed first by conducting semi-structured interviews with five of the nation’s leading flute pedagogues, chosen based on both the longevity and prestige of their performing career and the notable successes of current and former students. In alphabetical order, the subjects were: Leone Buyse, Marianne Gedigian, Amy Porter, Jim Walker, and Carol Wincenc. The interview questions were designed to uncover perceptions about the artist-teachers’ language use and how it relates to the six overarching topics discovered in the literature review. Upon completing and transcribing the interviews, the author “encoded” each transcription to discover common themes regarding the influences on the type of language used in lessons. The author performed every stage of research involved in this study, including the interview design, execution, and analyses. The study would be of use to any flutist, music teacher, or flute teacher who wishes to expand their knowledge of the complexity of music learning, increase their understanding of the intricacies of the one-to-one instruction model and explore the potentials for interconnectedness and musical creativity that result from thoughtful word choice.</p
Unemployment insurance in Algeria : implications for a labor market in transition
No full textTo predict how Algeria's unemployment crisis will evolve, the author evaluates the Algerian unemployment insurance system's ability to finance itself, to affect employment decisions, and promote enterprise restructuring. The main conclusion is that industrial restructuring has serious and persistent implications for the labor market. In an environment where many equilibria are possible, there is a real danger of reaching a high unemployment equilibrium. The big-bang experience of structural adjustment in Central and Eastern Europe transition economies resulted in large-scale unemployment. Despite considerable restructuring progress, structural rigidities still exist in the labor market, and long-term unemployment has persisted. One advantage of the big-bang approach is adjustment speed, but the resulting unemployment may be too costly for Algeria's economy, especially if it persists. A more modern mixed bang approach would incorporate active employment measures to mitigate entrenched unemployment. The policies will maintain or enhance human capital through work, so idle workers don't lose their skills. Flex-time arrangements would help workers maintain an attachment to the labor force. However minor, such work would help workers avoid the traps of long-term unemployment. Two striking conclusions emerge from the Central and Eastern European experience: a) unemployment is not essential to enterprise restructuring and labor market adjustment;and b) growing long-term unemployment is self-fulfilling and results in higher and persistence unemployment. Although active employment measures are costly and have relatively low rates of return in the short run, they can be marginally effective as part of a long-term strategy.Health Economics&Finance,Labor Policies,Environmental Economics&Policies,Labor Markets,Economic Theory&Research,Environmental Economics&Policies,Labor Markets,Economic Theory&Research,Health Economics&Finance,Banks&Banking Reform
Real-Time Composer-Performer Collaboration As Explored In Wilderness, A Dance And Audio Installation
No full textabstract: From fall 2010 to spring 2011, the author was the pianist in twenty public performances of Wilderness, a site-adaptable dance and audio installation by choreographer Yanira Castro and composer Stephan Moore. Wilderness's music was generated as the result of an algorithmic treatment of data collected from the movements of both dancers and audience members within the performance space. The immediacy of using movement to instantaneously generate sounds resulted in the need for a real-time notational environment inhabited by a sight-reading musician. Wilderness provided the author the opportunity to extensively explore an extreme sight-reading environment, as well as the experience of playing guided improvisations over existing materials while incorporating lateral thinking strategies, resulting from a real-time collaboration between composer and performer during the course of a live performance. This paper describes Wilderness in detail with particular attention focused on aspects of the work that most directly affect the pianist: the work's real-time notational system, live interaction between composer and performer, and the freedoms and limitations of guided improvisation. There is a significant amount of multi-media documentation of Wilderness available online, and the reader is directed toward this online content in the paper's appendix.Dissertation/ThesisD.M.A. Music 201
No 'maybes', only 'buts': the rhetorical art of the Prime Minister
No full textThe author reflects on the rhetorical aspect of the government of Australian Prime Minister John Howard. In her thesis 'Quarterly Essay: Relaxed and Comfortable: The Liberal Party's Australia,' Judith Brett claims that the strength of the prime minister lies in his ability to articulate ideas about Australian life. An assumption that the Howard rhetoric is about reassurance and re-enforcement of past certainties is said to contradict the fundamental radical nature of the program he pursued
The effects of Phytoestrogens on Estrogen ? and ? receptor expression in the brain of the male Syrian Hamster., 2007
No full textPhytoestrogens are diphenolic, non steroidal compounds which are present in plants and are consumed by both humans and animals. Previous investigations have demonstrated that dietary phytoestrogens appear to have neurobehavioral effects on intermale aggression in male Syrian hamsters and the neural mechanisms require further exploration. In this study experiments involving a phytoestrogen (PE) and a phytoestrogen free (PE Free) diet were performed to determine whether or not diet had an effect on the expression of a and p estrogen receptors in the brain of male Syrian hamsters (Mesocricetus auratus). Twenty male hamsters were used for experimentation and animals were divided into a PE (n = 10) and a PE Free group (n = 10) for a period of 3 weeks. Animals were sacrificed, perfused and brains removed for subsequent protein extraction and immunohistochemisty. Estrogen receptors were quantified using western blot utilizing brains from both the PE and the PE Free group. Results revealed a wide spread distribution of estrogen receptors throughout the brain of male Syrian hamsters. Positive irnmunoreactive labeling was observed in the thalamus, hypothalamus, amygdala, cortex and hipoocampus. Sections were matched and comparisons were made to determine which estrogen receptor had a higher rate of expression. Results revealed higher levels of ERP binding in comparison to ERa. In addition, there appeared to be a higher expression of estrogen receptors in animals on the PE Free diet (p < 0.05). Overall, results obtained form western blots support the hypothesis that animals on the PE Free diet experienced an increase in ER expression. Moreover, immunohistochemistry revealed visual differences of estrogen receptor expression in the brain and data suggests that a diet lacking phytoestrogens can up regulate estrogen receptors in male hamsters. In summary, we have demonstrated that manipulating the diet can have neurobiological consequences and future research should consider diet as a significant factor in experimental research on the brain
Community bank branch investment : motivations and consequences
No full textThis thesis was scanned from the print manuscript for digital preservation and is copyright the author.
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