1,539 research outputs found

    The Surgeon and the Patient with Cancer: The Development of Surgical Oncology

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    The Current Controversies in Surgical Management of Early Breast Cancer

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    The Role of Major Hepatic Resections for Liver Metastases from Colorectal Cancer

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    Of the more than 120,000 new patients with colorectal cancer in 1982, at least 20% will develop liver metastases either at initial presentation or after treatment of the primary lesion. The median survival in such patients has been variously estimated at between five and nine months, and in spite of treatment by chemotherapeutic agents, only rarely do such patients survive five years. By contrast, patients who survive the longest after treatment of liver metastases from colorectal cancer have had major hepatic resections alone or combined with chemotherapy as part of their management. The present report describes five patients who were treated for liver metastases by anatomic hepatic lobectomy, either alone or combined with other treatment approaches

    On how good DFT exchange-correlation functionals are for H bonds in small water clusters: Benchmarks approaching the complete basis set limit

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    The ability of several density-functional theory (DFT) exchange-correlation functionals to describe hydrogen bonds in small water clusters (dimer to pentamer) in their global minimum energy structures is evaluated with reference to second order Moeller Plesset perturbation theory (MP2). Errors from basis set incompleteness have been minimized in both the MP2 reference data and the DFT calculations, thus enabling a consistent systematic evaluation of the true performance of the tested functionals. Among all the functionals considered, the hybrid X3LYP and PBE0 functionals offer the best performance and among the non-hybrid GGA functionals mPWLYP and PBE1W perform the best. The popular BLYP and B3LYP functionals consistently underbind and PBE and PW91 display rather variable performance with cluster size.Comment: 9 pages including 4 figures; related publications can be found at http://www.fhi-berlin.mpg.de/th/th.htm

    The Supply of Private Acreage for Public Recreational Use in Southern and Central Appalachia

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    Public lands in Southern and Central Appalachia (SCA) available for outdoor recreational pursuits are limited relative to the rest of the county. This study identifies factors that encourage private land owners to permit public access to their land for recreational purposes and determines how much acreage would be offered in the Southern and Central Appalachia region. The Tobit and Heckman’s sample selection models suggest that the probability of offering land to the public is correlated with the number of acres offered. Having acreage suited for recreation is a positive determinant of acres leased but attributes developed by the landowner act as a disincentive. Type of recreational activity has no effect on the landowner’s decision and the supply of recreational acreage is inelastic with respect to price.private land lease, recreational activities, Tobit model, Heckman’s sample selection model, public recreational use, Environmental Economics and Policy, Land Economics/Use, Resource /Energy Economics and Policy, Q24, Q26,

    Coupled cluster benchmarks of water monomers and dimers extracted from DFT liquid water: the importance of monomer deformations

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    To understand the performance of popular density-functional theory (DFT) exchange-correlation (xc) functionals in simulations of liquid water, water monomers and dimers were extracted from a PBE simulation of liquid water and examined with coupled cluster with single and double excitations plus a perturbative correction for connected triples [CCSD(T)]. CCSD(T) reveals that most of the dimers are unbound compared to two gas phase equilibrium water monomers, largely because monomers within the liquid have distorted geometries. Of the three xc functionals tested, PBE and BLYP systematically underestimate the cost of the monomer deformations and consequently predict too large dissociation energies between monomers within the dimers. This is in marked contrast to how these functionals perform for an equilibrium water dimer and other small water clusters in the gas phase, which only have moderately deformed monomers. PBE0 reproduces the CCSD(T) monomer deformation energies very well and consequently the dimer dissociation energies much more accurately than PBE and BLYP. Although this study is limited to water monomers and dimers, the results reported here may provide an explanation for the overstructured radial distribution functions routinely observed in BLYP and PBE simulations of liquid water and are of relevance to water in other phases and to other associated molecular liquids.Comment: 10 pages, 8 figures, Submitted to Journal of Chemical Physics, Related information can be found in http://www.fhi-berlin.mpg.de/th

    Microscopic Mechanism and Kinetics of Ice Formation at Complex Interfaces: Zooming in on Kaolinite

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    Most ice in nature forms thanks to impurities which boost the exceedingly low nucleation rate of pure supercooled water. However, the microscopic details of ice nucleation on these substances remain largely unknown. Here, we have unraveled the molecular mechanism and the kinetics of ice formation on kaolinite, a clay mineral playing a key role in climate science. We find that the formation of ice at strong supercooling in the presence of this clay is twenty orders of magnitude faster than homogeneous freezing. The critical nucleus is substantially smaller than that found for homogeneous nucleation and, in contrast to the predictions of classical nucleation theory (CNT), it has a strong 2D character. Nonetheless, we show that CNT describes correctly the formation of ice at this complex interface. Kaolinite also promotes the exclusive nucleation of hexagonal ice, as opposed to homogeneous freezing where a mixture of cubic and hexagonal polytypes is observed

    One Health in food safety and security education: Subject matter outline for a curricular framework.

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    Educating students in the range of subjects encompassing food safety and security as approached from a One Health perspective requires consideration of a variety of different disciplines and the interrelationships among disciplines. The Western Institute for Food Safety and Security developed a subject matter outline to accompany a previously published One Health in food safety and security curricular framework. The subject matter covered in this outline encompasses a variety of topics and disciplines related to food safety and security including effects of food production on the environment. This subject matter outline should help guide curriculum development and education in One Health in food safety and security and provides useful information for educators, researchers, students, and public policy-makers facing the inherent challenges of maintaining and/or developing safe and secure food supplies without destroying Earth's natural resources
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