14,712 research outputs found
(63)Cu NQR Evidence for Spatial Variation of Hole Concentration in La(2-x)Sr(x)CuO(4)
We report experimental evidence for the spatial variation of hole
concentration x_(hole) in the high Tc superconductor La(2-x)Sr(x)CuO(4) (0.04
<= x <= 0.16) by using (63)Cu NQR for (63)Cu isotope enriched samples. We
demonstrate that the extent of the spatial variation of the local hole
concentration D(x)_(hole) is reflected on (63)1/T1 and deduce the temperature
dependence. D(x)_(hole) increases below 500 - 600K, and reaches values as large
as D(x)_(hole)/x ~ 0.5 below ~ 150K. We estimate the length scale of the
spatial variation in x_(hole) to be R_(hole) >~ 3nm from analysis of the NQR
spectrum.Comment: Accepted for publication in Physical Review Letter
Vegetarianism
Ethical vegetarians maintain that vegetarianism is morally required. The principal reasons offered in support of ethical vegetarianism are: (i) concern for the welfare and well-being of the animals being eaten, (ii) concern for the environment, (iii) concern over global food scarcity and the just distribution of resources, and (iv) concern for future generations. Each of these reasons is explored in turn, starting with a historical look at ethical vegetarianism and the moral status of animals
(13)C NMR investigation of the superconductor MgCNi_3 up to 800K
We report (13)C NMR characterization of the new superconductor MgCNi_3 (He et
al., Nature (411), 54 (2001)). We found that both the uniform spin
susceptibility and the spin fluctuations show a strong enhancement with
decreasing temperature, and saturate below ~50K and ~20K respectively. The
nuclear spin-lattice relaxation rate 1/(13)T_1T exhibits typical behaviour for
isotropic s-wave superconductivity with a coherence peak below Tc=7.0K that
grows with decreasing magnetic field.Comment: Accepted for publication in Physical Review Letter
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Media Discourse about Entrepreneurial Journalism: Implications for Journalistic Capital
Drawing on insights from field theory, this article examines journalists’ textual and discursive construction of entrepreneurial journalism from 2000 to 2014. The goal is to understand how such discursive practices contribute to the articulation and legitimation of entrepreneurial journalism as a form of cultural capital as the field’s economic imperatives change. The findings suggest that "entrepreneurial journalism" is a condensational term: it is defined broadly and loosely but generally in a positive way. Despite the potential for disruption to long-standing journalistic doxa, particularly normative stances related to the separation of editorial and commercial interests, much of the examined discourse seems to reflect a belief that entrepreneurialism is not only acceptable but even vital for survival in a digital age
Why Global Inequality Matters: Derivative Global Egalitarianism
This article integrates empirical and normative discussions about why global economic inequalities matter in critically examining an approach known as derivative global egalitarianism (DGE). DGE is a burgeoning perspective that opposes excessive global economic inequality not based on the intrinsic value of equality but inequality\u27s negative repercussions on other values. The article aims to advance the research agenda by identifying and critically evaluating four primary varieties of DGE arguments from related but distinct literatures, which span a number of disciplines, including economics, international relations, and political philosophy. Overall, DGE offers a number of persuasive arguments as to why current levels of global inequality are of concern, but aspects of DGE beg further philosophical and empirical examination. By situating DGE within the wider theoretical and empirical contexts, this article provides resources for its critical assessment and theoretical development
Focusing a deterministic single-ion beam
We focus down an ion beam consisting of single 40Ca+ ions to a spot size of a
few mum using an einzel-lens. Starting from a segmented linear Paul trap, we
have implemented a procedure which allows us to deterministically load a
predetermined number of ions by using the potential shaping capabilities of our
segmented ion trap. For single-ion loading, an efficiency of 96.7(7)% has been
achieved. These ions are then deterministically extracted out of the trap and
focused down to a 1sigma-spot radius of (4.6 \pm 1.3)mum at a distance of 257mm
from the trap center. Compared to former measurements without ion optics, the
einzel-lens is focusing down the single-ion beam by a factor of 12. Due to the
small beam divergence and narrow velocity distribution of our ion source,
chromatic and spherical aberration at the einzel-lens is vastly reduced,
presenting a promising starting point for focusing single ions on their way to
a substrate.Comment: 16 pages, 7 figure
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