1,907 research outputs found
Invariance of immersed Floer cohomology under Lagrangian surgery
We show that cellular Floer cohomology of an immersed Lagrangian brane is
invariant under smoothing of a self-intersection point if the quantum valuation
of the weakly bounding cochain vanishes and the Lagrangian has dimension at
least two. The chain-level map replaces the two orderings of the
self-intersection point with meridianal and longitudinal cells on the handle
created by the surgery, and uses a bijection between holomorphic disks
developed by Fukaya-Oh-Ohta-Ono. Our result generalizes invariance of
potentials for certain Lagrangian surfaces in
Dimitroglou-Rizell--Ekholm--Tonkonog, and implies the invariance of Floer
cohomology under mean curvature flow with this type of surgery, as conjectured
by Joyce.Comment: 100 pages. This version has minor corrections (one which was in the
isomorphism of Floer cohomologies, but which did not affect the main result.
Pseudospectral techniques for non -smooth evolutionary problems
A pseudospectral approach is used to solve non-smooth evolutionary problems using Fourier collocation and Chebyshev collocation. It is well known that pseudospectral methods for smooth problems can offer superior accuracy over finite difference and finite element methods.;This paper explores the use of pseudospectral methods for non-smooth evolutionary problems in the area of hyperbolic heat transfer. Boundary and initial conditions are considered which cause instantaneous jumps, in the temperature and flux, prior to the propagation of a thermal wave into the medium. There is a considerable amount of literature that has investigated hyperbolic heat transfer under similar conditions, the common problems throughout theses investigations is the presence of numerical oscillation at the wave front. Finite difference and finite element methods have both been used, and both methods exhibit severe numerical oscillation at the wave front. In an attempt to reduce this oscillation extremely fine grids and severe timestep restrictions had to be introduced, but even these attempts still exhibited some oscillation.;This paper will demonstrate that pseudospectral methods, when used correctly, can eliminate the numerical oscillation at the wave front and accurately resolve the instantaneous jump at the boundary. Furthermore, pseudospectral methods can be used successfully with coarser grids and larger timesteps and still provide superior results.;This paper will also investigate hyperbolic heat transfer with boundary conditions that contain a continuous periodic flux with surface radiation. These boundary conditions have never before been investigated in the literature on hyperbolic heat transfer. Previous research has only considered boundary conditions that contain a constant flux with radiation r a periodic on-off pulse with radiation. In either case, extremely fine grids were needed to prevent severe numerical oscillation. This paper will compare the hyperbolic and parabolic thermal response due to the periodic flux, under a wide range of frequencies, as well as show how pseudospectral methods can be used successfully in the case of periodic flux with surface radiation without the need to introduce fine spatial grids and prohibitively small timesteps
Won\u27t Get Fooled Again: The Dogma of Quine\u27s “Two Dogmas”
[From the Introduction]
In the 1950’s, W.V.O. Quine published what he thought was a crippling blow to the analytic/synthetic distinction. Hailed as one of the most important philosophical articles in the 20th century, the “Two Dogmas of Empiricism” sought to demonstrate how the concept of analyticity is circular in nature. The conclusions that Quine drew from this argument envisioned the collapse of reductionism and, subsequently, the verification theory. Both were theories central to the logical positivists whose hard-nosed doctrine dominated Anglo-American philosophy for much of early 20th Century. Although it has attracted criticism and praise, the article has held a profound influence in Western philosophy.
Unfortunately, the article is flawed in the same manner the author critiques analyticity and the two doctrines following in its wake: the “Two Dogmas” is dogmatic itself. Quine’s essay strictly holds to ideas and claims that are clearly not true, highly contested, or preposterous. This article’s first critique exposes two major dogmatisms cleverly embedded under the superficial and swift analysis. Readers are required to agree with Quine on the assertion that all definitions are synonyms. This ignores axiological components of the relationship between them as well as demand agreement with the Cluster theory of naming. The second dogmatism is the blatant ignorance of two extremely conflicting theories of meaning (logical positivist and ordinary language philosophy) that is embodied in his dual categories of analyticity. For Quine to bridge the gap between the theories and ground analyticity, what he really did was set up an impossible task of needing to conform one theory of meaning to another. The third dogmatism that Quine, his followers and his critics are guilty of is the avoidance of syntheticity, thereby leaving the other half of the analytic/synthetic dichotomy untouched
Assessing water quality improvement schemes: The multi-attribute technique of the UK’s environment agency
The Environment Agency for England and Wales is required to take account of likely costs and benefits in carrying out its duties. Given the complex nature of environmental problems, this task requires sensitivity to issues such as uncertainty, multiple objectives and conflicting value systems. This paper describes a multi-attribute methodology used to carry out this duty in one area of the Agency’s work, the regulation of the water industry. The method includes nine attributes measuring the benefits from water quality improvement schemes, and one attribute measuring scheme costs. It is a workable method that clearly satisfies the requirements for the Environment Agency to take account of the costs and benefits of its actions. Refinements are suggested to improve the individual attribute scores, the weights used in prioritisation and the incorporation of costs
Bayesian evaluation of the southern hemisphere radiocarbon offset during the holocene
While an interhemispheric offset in atmospheric radiocarbon levels from AD 1950–950 is now well established, its existence earlier in the Holocene is less clear, with some studies reporting globally uniform 14C levels while others finding Southern Hemisphere samples older by a few decades. In this paper, we present a method for wiggle-matching Southern Hemisphere data sets against Northern Hemisphere curves, using the Bayesian calibration program OxCal 4.1 with the Reservoir Offset function accommodating a potential interhemispheric offset. The accuracy and robustness of this approach is confirmed by wiggle-matching known-calendar age sequences of the Southern Hemisphere calibration curve SHCal04 against the Northern Hemisphere curve IntCal04. We also show that 5 of 9 Holocene Southern Hemisphere data sets are capable of yielding reliable offset information. Those data sets that are accurate and precise show that interhemispheric offset levels in the Early Holocene are similar to modern levels, confirming SHCal04 as the curve of choice for calibrating Southern Hemisphere samples
Is there any Evidence for Regional Atmospheric 14C Offsets in the Southern Hemisphere?
Center for Accelerator Mass Spectrometry (CAMS) Tasmanian huon pine (Lagarostrobos franklinii) decadal measurements for the interval AD 745–855 suggest a mean interhemispheric radiocarbon offset (20 ± 5 yr), which is considerably lower than the previously reported mean interhemispheric offset for the last 2 millennia (44 ± 17 yr). However, comparable University of Waikato (Wk) New Zealand kauri (Agathis australis) measurements show significantly higher values (56 ± 6 yr), suggesting the possibility of a temporary geographic (intrahemispheric) offset between Tasmania, Australia, and Northland, New Zealand, during at least 1 common time interval. Here, we report 9 new Wk Tasmanian huon pine measurements from the decades showing the largest huon/kauri difference. We show statistically indistinguishable Wk huon and Wk kauri 14C ages, thus dispelling the suggestion of a 14C geographic offset between Tasmania and Northland
IS 502 Christian Formation: Vocation of Ministry
Chilcote, P.W. (1986) John Wesley Speaks on Christian Vocation. Eugene, OR: Wipf and Stock Publishers. Foster, R. (1978) Celebration of Discipline. San Francisco: Harper Collins. Foster, R. (1983) Study Guide for Celebration of Discipline. San Francisco: Harper Collins. Grenz, S. & Bell, R. (1995). Betrayal of Trust: Sexual Misconduct in the Pastorate. Downers Grove, IL: InterVarsity Press. Groothuis, R.M. (1997). Good News for Women: A Biblical Picture of Gender Equality, Grand Rapids, MI: Baker. Guiness, O. (1998). The Call: Finding and Fulfilling the Central Purpose of Your Life. Waco,TX: Word. Sire, J.W. (2000). Habits of the Mind: Intellectual Life as a Christian Calling. Downers Grove, IL: InterVarsity Press. Smith, G. (1997). Listening to God in Times of Choice, Downers Grove, IL: InterVarsity Press.https://place.asburyseminary.edu/syllabi/2670/thumbnail.jp
Robust radiocarbon dating of wood samples by high-sensitivity liquid scintillation spectroscopy in the 50–70 kyr age range
Although high-sensitivity liquid scintillation (LS) spectroscopy is theoretically capable of producing finite radiocarbon ages in the 50,000- to 70,000-yr range, there is little evidence in the literature that meaningful dates in this time period have been obtained. The pressing need to undertake calibration beyond 26 kyr has resulted in the regular publication of ¹⁴C results in excess of 50 kyr, yet very little effort has been made to demonstrate their accuracy or precision. There is a paucity of systematic studies of the techniques required to produce reliable dates close to background and the methods needed to assess contamination from either in situ sources or laboratory handling and processing. We have studied the requirements for producing accurate and reliable dates beyond 50 kyr. Laboratory procedures include optimization of LS spectrometers to obtain low and stable non-¹⁴C background count rates, use of low-background counting vials, large benzene volumes, long counting times, and preconditioning of vacuum lines. We also discuss the need for multiple analyses of a suitable material containing no original ¹⁴C (background blank) and the application of an appropriate statistical model to compensate for variability in background contamination beyond counting statistics. Accurate and reproducible finite ages >60 kyr are indeed possible by high-sensitivity LS spectroscopy, but require corroborating background blank data to be defensible
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