2,802 research outputs found

    The Liability of Stockholders of a Corporation to Corporate Creditors

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    Money, sex and happiness : an empirical study

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    The links between income, sexual behavior and reported happiness are studied using recent data on a sample of 16,000 adult Americans. The paper finds that sexual activity enters strongly positively in happiness equations. Higher income does not buy more sex or more sexual partners. Married people have more sex than those who are single, divorced, widowed or separated. The happiness‐maximizing number of sexual partners in the previous year is calculated to be 1. Highly educated females tend to have fewer sexual partners. Homosexuality has no statistically significant effect on happiness

    Quark structure of pseudoscalar mesons

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    I review to which extent the properties of pseudoscalar mesons can be understood in terms of the underlying quark (and eventually gluon) structure. Special emphasis is put on the progress in our understanding of eta-eta' mixing. Process-independent mixing parameters are defined, and relations between different bases and conventions are studied. Both, the low-energy description in the framework of Chiral Perturbation Theory and the high-energy application in terms of light-cone wave functions for partonic Fock states, are considered. A thorough discussion of theoretical and phenomenological consequences of the mixing approach will be given. Finally, I will discuss mixing with other states pi^0, eta(c), ...).Comment: 48 pages, 7 figures, using epsfig.st

    Polyurethane Elastomers as Maxillofacial Prosthetic Materials

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    A series of polyurethane elastomers based on an aliphatic diisocyanate and a polyether macroglycol was polymerized with various crosslink densities and OH/NCO ratios. Stoichiometries yielding between 8,600 and 12,900 gm/ mole/crosslink and an OH/NCO ratio of 1.1 resulted in polymers with the low modulus, yet high strength and elongation necessary for maxillofacial applications.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68299/2/10.1177_00220345780570040501.pd

    Vector meson dominance and the rho meson

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    We discuss the properties of vector mesons, in particular the rho^0, in the context of the Hidden Local Symmetry (HLS) model. This provides a unified framework to study several aspects of the low energy QCD sector. Firstly, we show that in the HLS model the physical photon is massless, without requiring off field diagonalization. We then demonstrate the equivalence of HLS and the two existing representations of vector meson dominance, VMD1 and VMD2, at both tree level and one loop order. Finally the S matrix pole position is shown to provide a model and process independent means of specifying the rho mass and width, in contrast to the real axis prescription currently used in the Particle Data Group tables.Comment: 18 pages, REVTE

    Satellite sensor requirements for monitoring essential biodiversity variables of coastal ecosystems

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    The biodiversity and high productivity of coastal terrestrial and aquatic habitats are the foundation for important benefits to human societies around the world. These globally distributed habitats need frequent and broad systematic assessments, but field surveys only cover a small fraction of these areas. Satellite-based sensors can repeatedly record the visible and near-infrared reflectance spectra that contain the absorption, scattering, and fluorescence signatures of functional phytoplankton groups, colored dissolved matter, and particulate matter near the surface ocean, and of biologically structured habitats (floating and emergent vegetation, benthic habitats like coral, seagrass, and algae). These measures can be incorporated into Essential Biodiversity Variables (EBVs), including the distribution, abundance, and traits of groups of species populations, and used to evaluate habitat fragmentation. However, current and planned satellites are not designed to observe the EBVs that change rapidly with extreme tides, salinity, temperatures, storms, pollution, or physical habitat destruction over scales relevant to human activity. Making these observations requires a new generation of satellite sensors able to sample with these combined characteristics: (1) spatial resolution on the order of 30 to 100-m pixels or smaller; (2) spectral resolution on the order of 5 nm in the visible and 10 nm in the short-wave infrared spectrum (or at least two or more bands at 1,030, 1,240, 1,630, 2,125, and/or 2,260 nm) for atmospheric correction and aquatic and vegetation assessments; (3) radiometric quality with signal to noise ratios (SNR) above 800 (relative to signal levels typical of the open ocean), 14-bit digitization, absolute radiometric calibration \u3c2%, relative calibration of 0.2%, polarization sensitivity \u3c1%, high radiometric stability and linearity, and operations designed to minimize sunglint; and (4) temporal resolution of hours to days. We refer to these combined specifications as H4 imaging. Enabling H4 imaging is vital for the conservation and management of global biodiversity and ecosystem services, including food provisioning and water security. An agile satellite in a 3-d repeat low-Earth orbit could sample 30-km swath images of several hundred coastal habitats daily. Nine H4 satellites would provide weekly coverage of global coastal zones. Such satellite constellations are now feasible and are used in various applications

    Multi-level selection and the issue of environmental homogeneity

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    In this paper, I identify two general positions with respect to the relationship between environment and natural selection. These positions consist in claiming that selective claims need and, respectively, need not be relativized to homogenous environments. I then show that adopting one or the other position makes a difference with respect to the way in which the effects of selection are to be measured in certain cases in which the focal population is distributed over heterogeneous environments. Moreover, I show that these two positions lead to two different interpretations – the Pricean and contextualist ones – of a type of selection scenarios in which multiple groups varying in properties affect the change in the metapopulation mean of individual-level traits. Showing that these two interpretations stem from different attitudes towards environmental homogeneity allows me to argue: a) that, unlike the Pricean interpretation, the contextualist interpretation can only claim that drift or selection is responsible for the change in frequency of the focal trait in a given metapopulation if details about whether or not group formation is random are specified; b) that the traditional main objection against the Pricean interpretation – consisting in arguing that the latter takes certain side-effects of individual selection to be effects of group selection – is unconvincing. This leads me to suggest that the ongoing debate about which of the two interpretations is preferable should concentrate on different issues than previously thought
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