866 research outputs found
A Bayesian approach to the estimation of maps between riemannian manifolds
Let \Theta be a smooth compact oriented manifold without boundary, embedded
in a euclidean space and let \gamma be a smooth map \Theta into a riemannian
manifold \Lambda. An unknown state \theta \in \Theta is observed via
X=\theta+\epsilon \xi where \epsilon>0 is a small parameter and \xi is a white
Gaussian noise. For a given smooth prior on \Theta and smooth estimator g of
the map \gamma we derive a second-order asymptotic expansion for the related
Bayesian risk. The calculation involves the geometry of the underlying spaces
\Theta and \Lambda, in particular, the integration-by-parts formula. Using this
result, a second-order minimax estimator of \gamma is found based on the modern
theory of harmonic maps and hypo-elliptic differential operators.Comment: 20 pages, no figures published version includes correction to eq.s
31, 41, 4
Production and application of chemical fibers with special properties for manufacturing composite materials and goods of different usage
The development of modern technologies demands the creation of new nonmetallic, fibrous materials with specific properties. The fibers and materials developed by NII 'Chimvolokno', St. Petersburg, can be divided into two groups. The first group includes heat-resistant fibers, fire-resistant fibers, thermotropic fibers, fibers for medical application, and textile structures. The second group contains refractory fibers, chemoresistant and antifriction fibers, fibers on the basis of polyvinyl alcohol, microfiltering films, and paperlike and nonwoven materials. In cooperation with NPO 'Chimvolokno' MYTITSHI, we developed and started producing heat-resistant high-strength fibers on the base of polyhetarearilin and aromatic polyimides (SVM and terlon); heat-resistant fibers on the base of polyemede (aramid); fire-retardant fibers (togilen); chemoresistant and antifriction fibers on the basis of homo and copolymers of polytetrafluoroethylene (polyfen and ftorin); and water soluble, acetylated, and high-modulus fibers from polyvinyl alcohol (vylen). Separate reports will deal with textile structures and thermotropic fibers, as well as with medical fibers. One of the groups of refractory fibers carbon fibers (CF) and the corresponding paperlike nonwoven materials are discussed in detail. Also, composite materials (CM) and their base, which is the subject of the author's research since 1968, is discussed
Viewpoints: A high-performance high-dimensional exploratory data analysis tool
Scientific data sets continue to increase in both size and complexity. In the
past, dedicated graphics systems at supercomputing centers were required to
visualize large data sets, but as the price of commodity graphics hardware has
dropped and its capability has increased, it is now possible, in principle, to
view large complex data sets on a single workstation. To do this in practice,
an investigator will need software that is written to take advantage of the
relevant graphics hardware. The Viewpoints visualization package described
herein is an example of such software. Viewpoints is an interactive tool for
exploratory visual analysis of large, high-dimensional (multivariate) data. It
leverages the capabilities of modern graphics boards (GPUs) to run on a single
workstation or laptop. Viewpoints is minimalist: it attempts to do a small set
of useful things very well (or at least very quickly) in comparison with
similar packages today. Its basic feature set includes linked scatter plots
with brushing, dynamic histograms, normalization and outlier detection/removal.
Viewpoints was originally designed for astrophysicists, but it has since been
used in a variety of fields that range from astronomy, quantum chemistry, fluid
dynamics, machine learning, bioinformatics, and finance to information
technology server log mining. In this article, we describe the Viewpoints
package and show examples of its usage.Comment: 18 pages, 3 figures, PASP in press, this version corresponds more
closely to that to be publishe
Women, Rule-Breaking, and The Triple Bind
Two growing literatures critique Hobbesian corporate cultures. Management analyses document the way high-stakes/zero-sum bonus systems undermine, rather than enhance, productivity as they subvert teamwork, valorize self-interested behavior, and weaken ethical standards. This literature treats negative effects of such systems, including lawless and unethical behavior, as the unintended consequences of efforts to shake up complacent institutions or replace an insular old guard with an ambitious and meritocratic new workforce. A second, darker literature terms such Hobbesian environments “masculinities contests” that select for those executives who best exemplify masculine traits such as a single-minded focus on professional success, physical strength, and the willingness to engage in no-holds-barred competition. This literature treats the rule-breaking environment that results as an incidental byproduct of the way that such cultures valorize masculine traits. Drawing on insights from criminology, psychology, and feminist theory, this Article suggests another possibility: that certain management cultures intentionally design the competitions to facilitate breaking the rules with impunity.
In a Hobbesian world, where some profit handsomely from defying convention, zero-sum competitions play a role that extends beyond valorizing alpha males. They select for leaders who will lie, shortchange their families, and break the law to get results—and do so without explicit orders that might subject upper management to accountability for the practices. In such a world, women fall behind not necessarily because of misogyny, though such environments often breed it. Instead, they lose because of a triple bind. First, women cannot prevail in such competitions unless they can outmaneuver men, credibly display greater devotion to the job, or more brazenly flout the laws. Second, they are disproportionately disliked and punished for displaying the self-centered, rule-breaking behavior of men. Third, women become less likely to seek positions because they correctly perceive that they could not thrive and are more likely than men to decide they do not wish to do so on such terms, reinforcing the male-identified character of such environments. Where these companies’ business models depend not just on the ability to upend traditional practices, but to break the law, the companies cannot address gender disparities without addressing the business model itself. The Article concludes that gender inequality is intrinsically intertwined with the evisceration of the rule of law in corporate America
Semiclassical treatment of fusion processes in collisions of weakly bound nuclei
We describe a semiclassical treatment of nuclear fusion reactions involving
weakly bound nuclei. In this treatment, the complete fusion probabilities are
approximated by products of two factors: a tunneling probability and the
probability that the system is in its ground state at the strong absorption
radius. We investigate the validity of the method in a schematic two-channel
application, where the channels in the continuum are represented by a single
resonant state. Comparisons with full coupled-channels calculations are
performed. The agreement between semiclassical and quantal calculations isquite
good, suggesting that the procedure may be extended to more sophisticated
discretizations of the continuum.Comment: 11 pages, 5 figure
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The Federal Debt: An Analysis of Movements from World War II to the Present
This report will define the measures of debt, discuss the reasons why debt levels change, and use historical examples to illustrate the factors causing debt movements over the last seven decades. Recent policies that have affected the budgetary outlook and the debt will also be discussed. Finally, this report will examine the long-term U.S. debt outlook and implications of rising federal debt levels
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The Federal Budget: Issues for FY2011, FY2012, and Beyond
This report examines the federal budgets for the fiscal years 2011 and 2012. It gives an overview of the federal budget, addresses the problems of budgeting in a strained economy, and discusses considerations for Congress, both in the short term and the long term
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Impact on the Federal Budget of Freezing Non-Security Discretionary Spending
This report examines the impact on the federal budget of the President’s proposals, specifically the proposed freeze in non-security discretionary spending and how the freeze might change the fiscal outlook over the 10-year budget window
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The Budget Control Act of 2011: Budgetary Effects of Proposals to Replace the FY2013 Sequester
Report that provides information on the levels of deficit reduction if the Budget Control Act's (BCA) automatic cuts are implemented as under current law and contrasts that with the alternative proposals offered by some Members of Congress and President Obama. It also discusses specific determinations made by the Office of Management and Budget regarding the exempt/non-exempt status of certain programs, as well as a discussion of information to be disclosed regarding the FY2013 BCA sequester impact
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Reducing the Budget Deficit: The President's Fiscal Commission and Other Initiatives
This report discusses why the federal government's fiscal path is unsustainable and provides an overview of proposals of selected groups that have published detailed recommendations on how to return the federal budget to a sustainable course
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