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Knowledge of the spatial distribution of bed lubrication regimes, i.e. frozen vs wet conditions, is crucial for understanding ice-sheet flow. Radar sounding can probe differing reflectivities between wet and frozen beds, but is limited by uncertainty in attenuation within the ice of bed echoes. Here we present two methods to estimate attenuation: (1) wide-angle radar sounding, in which source and receiver locations are varied so as to vary propagation path length, and thus echo amplitude; and (2) profiling, inwhich similar variations are obtained by sounding through varying ice thicknesses (assuming constant bed reflectivity). Siple Dome, West Antarctica, provides unusually favorable circumstances for application of these methods: the bed beneath Siple Dome is flat and uniform in its radar reflectivity, while ice thickness varies by several hundred meters. Wide-angle data 4 km from the summit yield an estimate for characteristic attenuation length of 124 m (35 dB km–1 loss), whereas profiling yields an estimate of 168 m.The difference between estimates is modest compared to the range of attenuation lengths reported in the literature. It may nonetheless prove informative by bounding effects of two ice properties to which the methods respond differently: (1) wide-angle sounding sampled relatively warm (lossy) ice beneath the summit, whereas the profiling method sampled relatively cold ice beneath the flanks as well; and (2) strain-induced crystal orientation fabrics and resulting dielectric anisotropy in the ice would vary from summit to flank, and may influence wide-angle sounding more strongly than profiling.
Population has been increasing for at least a decade in rural areas of West Virginia as in many areas of the Nation. This phenomenon is transforming rural areas, with problems of growth replacing those of decline. If local governments, the extension service and others are to cope adequately with this emerging set of problems, more must be learned about the newer residents, their attitudes, needs and how they relate to those of the rest of the population in the area. A number of recent analyses of rural development attest to the serious data gap that exists with respect to knowledge in the area (Beal; Fuguitt, Voss and Doherty; Gilford, Nelson, and Ingram; Powers and Moe in Dillman and Hobbs, p. 14; and Sofranko and Williams). This paper reports on a 1981 survey of rural residents in nine selected West Virginia counties, a survey which was conducted to help solve the data gap problems.
This article explores the divisions created by the Great Patriotic War, its aftermath and the reconstruction of Russian cities in the late 1940s and early 1950s. It examines the conflicts created by rebuilding housing, infrastructure, restoring communities and allocating resources in cities where war's painful legacy continued to be felt. The war's impact varied enormously between cities on the frontlines and in the rear. Contrary to official propaganda rebuilding was a protracted process, which created divisions rather than unity.
In recent years, there has been renewed interest in the question of whether Ronald Dworkin was correct to allege that legal positivists are unable to account for theoretical disagreement about law. However, relatively little attention has been paid to the related question of who can best account for agreement about law. An important exception is Brian Leiter’s argument that there is massive and pervasive agreement in legal judgments and that positivism can account for this agreement but Dworkin cannot. In this article, I argue that Dworkin can account for such agreement, and that his explanation is no less straightforward than the positivist’s. I further contend that Leiter’s strategy for explaining theoretical disagreement is weakened once we recognise that Dworkin has a plausible explanation of agreement in legal judgments. I conclude by exploring how we might choose between the positivist’s and Dworkin’s competing explanations of agreement in legal judgments.
In 2008, avian bornaviruses (ABV) were identified as the cause of proventricular dilatation disease (PDD). PDD is a significant condition of captive parrots first identified in the late 1970s. ABV infection has subsequently been shown to be widespread in wild waterfowl across the United States and Canada where the virus infects 10–20% of some populations of ducks, geese and swans. In most cases birds appear to be healthy and unaffected by the presence of the virus; however, infection can also result in severe non-suppurative encephalitis and lesions similar to those seen in parrots with PDD. ABVs are genetically diverse with seven identified genotypes in parrots and one in canaries. A unique goose genotype (ABV-CG) predominates in waterfowl in Canada and the northern United States. ABV appears to be endemic in North American waterfowl, in comparison to what appears to be an emerging disease in parrots. It is not known whether ABV can spread between waterfowl and parrots. The discovery of ABV infection in North American waterfowl suggests that European waterfowl should be evaluated for the presence of ABV, and also as a possible reservoir species for Borna disease virus (BDV), a related neurotropic virus affecting horses and sheep in central Europe. Although investigations have suggested that BDV is likely derived from a wildlife reservoir, for which the shrew and water vole are currently prime candidates, we suggest that the existence of other mammalian and avian reservoirs should not be discounted.
Joseph Raz famously argues that given that the law necessarily claims authority and given the account of authority he provides, exclusive legal positivism is the only tenable theory of law. In this article, I contend that even if one accepts that the law necessarily claims authority and that Raz's account of authority is correct, it does not follow that exclusive legal positivism is the only tenable theory of law. This is because even if the law necessarily claims authority, it need not be capable of satisfying the requirements for possessing authority laid down by the correct account of authority. Thus, even if exclusive legal positivism is the only theory of law according to which the law can satisfy those requirements, this does not show that exclusive legal positivism is correct.
In this paper, I shall consider operators generated by difference equations of the form
where Δ is the forward difference operator, and a, p, and r are sequences of real numbers. The connection between the oscillation constant of this equation and the bottom of the essential spectrum of self-adjoint extensions of the operator generated by the equation is given, as well as various other information about the spectrum of such extensions. In particular, I derive conditions for the spectrum to have only countably many eigenvalues below zero, and a simple criterion for the invariance of the essential spectrum.
We present photometry and spectroscopy of the peculiar Type II supernova SN 2010jp, also named PTF10aaxi. The light curve exhibits a linear decline with a relatively low peak absolute magnitude of only −15.9 (unfiltered), and a low radioactive decay luminosity at late times that suggests a low synthesized nickel mass of about 0.003 M⊙ or less. Spectra of SN 2010jp display an unprecedented triple-peaked Hα line profile, showing: (1) a narrow central component that suggests shock interaction with a dense circumstellar medium (CSM); (2) high-velocity blue and red emission features centered at −12,600 and +15,400 km s−1; and (3) very broad wings extending from −22,000 to +25,000 km s−1. We propose that this line profile indicates a bipolar jet-driven explosion, with the central component produced by normal SN ejecta and CSM interaction at mid and low latitudes, while the high-velocity bumps and broad line wings arise in a nonrelativistic bipolar jet. Jet-driven SNe II are predicted for collapsars resulting from a wide range of initial masses above 25 M⊙, especially at the sub-solar metallicity consistent with the SN host environment. It also seems consistent with the apparently low 56Ni mass that may accompany black hole formation. We speculate that the jet survives to produce observable signatures because the star's H envelope was very low mass, having been mostly stripped away by the previous eruptive mass loss.
Soft x-ray synchrotron radiation has been utilized as the excitation source in a high-resolution photoemission experiment designed to investigate the chemisorption and subsequent reaction of diethylsilane on the technologically important Si(100) surface. We have found that diethylsilane chemisorbs dissociatively to form Si-CH2CH3 surface species on Si(100) following a room temperature exposure. These species are identified by two very sharp peaks observed in the valence band spectra positioned at 17.9 and 14.3 eV binding energy. In addition, C Is core level spectra, measured following exposures of Si(100) substrates as a function of surface temperature, show that carbon, in some form, exists on the Si surface following exposures at every temperature from room temperature to about 600°C. While only -CH2CH3 ethyl groups are observed on the surface at room temperature, these species appear to partially dehydrogenate at 300°C, producing a mixture of -CH2CH3 groups and other intermediate carbonaceous species. At a growth temperature of about 400°C the intermixing of elemental carbon with Si begins. At higher temperatures, we observe the continued degradation of diethylsilane to produce a Si + C alloy on the surface at 600°C. Our results indicate that diethylsilane has potential as a molecular precursor for SiC formation by chemical vapor deposition techniques.
Twenty-three years after its publication, Maurice Merleau-Ponty's The Visible and the Invisible remains a philosophical enigma. Consider, for example, the curious niche the work occupies within the body of phenomenological literature. The Visible and the Invisible is frequently cited for its study of the residual problem areas of phenomenology—the relationship of consciousness to the perceptual milieu and, more recently, the relationship of language to the world—while its proposed solutions to such problems remain largely ignored.
Current attempts to understand and remedy the underdevelopment and peripheral international roles of Third World states derive from three competing paradigms: conventional social science, Marxism, and dependency theory. Each paradigm claims to explain past history and to make relevant policy recommendations for Third World leaders. Yet, none of these approaches has so far been formulated as complex, well specified, causal models. One can build theory relevant to data by specifying competing three-variable models relating economic dependency to economic performance and development potential. An empirical evaluation can then be made of the dependency theory proposition that economic dependency inhibits positive economic performance (growth and development). Partial correlation and regression analyses of economic data from thirty tropical African states in the middle and late 1960s provide little support for two dependency-based models and evidence in favor of conventional and Marxist models. These findings have implications for theory, further research, and policy.
Ronald Dworkin has repeatedly claimed that the debate between moral objectivists and anti-objectivists (which I shall call “the meta-ethical debate”) has no implications for legal practice or theory. He has offered two main arguments to support this claim. The first is that while assertions about the truth or falsity of moral objectivism may be intelligible, they are irrelevant to legal practice and theory. The second is more radical, namely, that no assertion can be given an intelligible meta-ethical reading. In this article, I contend that neither argument is sound. The first argument overlooks the variety of ways in which the meta-ethical debate could impact upon legal practice or theory. It also rests upon an uncharitable interpretation of that debate. As for the second argument, Dworkin is correct in claiming that statements seemingly about the truth or falsity of moral objectivism can instead be interpreted as moral statements, but he is wrong to claim that this is the only intelligible reading they can be given.