Institution
University of Cambridge
Education•Cambridge, United Kingdom•
About: University of Cambridge is a education organization based out in Cambridge, United Kingdom. It is known for research contribution in the topics: Population & Galaxy. The organization has 118293 authors who have published 282289 publications receiving 14497093 citations. The organization is also known as: Cambridge University & Cambridge.
Topics: Population, Galaxy, Context (language use), Gene, Transplantation
Papers published on a yearly basis
Papers
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TL;DR: In this paper, the authors presented tensile stress strain data for 99.999% copper at room and liquid nitrogen temperature as a function of grain size with some microstructural observations made by transmission electron microscopy.
267 citations
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13 Dec 2010TL;DR: A study of the relationship between preferences for social events and geography, the first of its kind in a large metropolitan area, finds that the most effective algorithm recommends events that are popular among residents of an area, while the least effective recommendsEvents that are geographically close to the area, has interesting implications for location-based services that emphasize recommending nearby events.
Abstract: A city offers thousands of social events a day, and it is difficult for dwellers to make choices. The combination of mobile phones and recommender systems can change the way one deals with such abundance. Mobile phones with positioning technology are now widely available, making it easy for people to broadcast their whereabouts, recommender systems can now identify patterns in people’s movements in order to, for example, recommend events. To do so, the system relies on having mobile users who share their attendance at a large number of social events: cold-start users, who have no location history, cannot receive recommendations. We set out to address the mobile cold-start problem by answering the following research question: how can social events be recommended to a cold-start user based only on his home location? To answer this question, we carry out a study of the relationship between preferences for social events and geography, the first of its kind in a large metropolitan area. We sample location estimations of one million mobile phone users in Greater Boston, combine the sample with social events in the same area, and infer the social events attended by 2,519 residents. Upon this data, we test a variety of algorithms for recommending social events. We find that the most effective algorithm recommends events that are popular among residents of an area. The least effective, instead, recommends events that are geographically close to the area. This last result has interesting implications for location-based services that emphasize recommending nearby events.
267 citations
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TL;DR: A theoretical framework within which the properties of cluster methods, which operate on data in the form of a dissimilarity coefficient on a set of objects, may be discussed is outlined.
Abstract: Many of the cluster methods that are used in the construction of classificatory systems operate on data in the form of a dissimilarity coefficient on a set of objects. In this paper we outline a theoretical framework within which the properties of such methods may be discussed. Certain conditions that a cluster method should satisfy are suggested, and a particular sequence of cluster methods which satisfies these conditions is described. The application of the sequence of methods is illustrated by a simple example.
267 citations
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Goddard Institute for Space Studies1, University of Edinburgh2, Wageningen University and Research Centre3, National Center for Atmospheric Research4, Earth System Research Laboratory5, University of Oslo6, Max Planck Society7, Japan Agency for Marine-Earth Science and Technology8, University of Cambridge9, International Institute for Applied Systems Analysis10, Lawrence Livermore National Laboratory11, École Polytechnique12, Met Office13, Newbury College14, Royal Netherlands Meteorological Institute15, Geophysical Fluid Dynamics Laboratory16, Belgian Institute for Space Aeronomy17, University of California, Irvine18, Goddard Space Flight Center19
TL;DR: This article analyzed present-day and future carbon monoxide (CO) simulations in 26 state-of-the-art atmospheric chemistry models run to study future air quality and climate change.
Abstract: We analyze present-day and future carbon monoxide (CO) simulations in 26 state-of-the-art atmospheric chemistry models run to study future air quality and climate change. In comparison with near-global satellite observations from the MOPITT instrument and local surface measurements, the models show large underestimates of Northern Hemisphere (NH) extratropical CO, while typically performing reasonably well elsewhere. The results suggest that year-round emissions, probably from fossil fuel burning in east Asia and seasonal biomass burning emissions in south-central Africa, are greatly underestimated in current inventories such as IIASA and EDGAR3.2. Variability among models is large, likely resulting primarily from intermodel differences in representations and emissions of nonmethane volatile organic compounds (NMVOCs) and in hydrologic cycles, which affect OH and soluble hydrocarbon intermediates. Global mean projections of the 2030 CO response to emissions changes are quite robust. Global mean midtropospheric (500 hPa) CO increases by 12.6 ± 3.5 ppbv (16%) for the high-emissions (A2) scenario, by 1.7 ± 1.8 ppbv (2%) for the midrange (CLE) scenario, and decreases by 8.1 ± 2.3 ppbv (11%) for the low-emissions (MFR) scenario. Projected 2030 climate changes decrease global 500 hPa CO by 1.4 ± 1.4 ppbv. Local changes can be much larger. In response to climate change, substantial effects are seen in the tropics, but intermodel variability is quite large. The regional CO responses to emissions changes are robust across models, however. These range from decreases of 10–20 ppbv over much of the industrialized NH for the CLE scenario to CO increases worldwide and year-round under A2, with the largest changes over central Africa (20–30 ppbv), southern Brazil (20–35 ppbv) and south and east Asia (30–70 ppbv). The trajectory of future emissions thus has the potential to profoundly affect air quality over most of the world's populated areas.
267 citations
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TL;DR: Comparison of the acetylation states of carnitine and CoA in perfused hearts suggests that the carn itine acetyltransferase reactants may remain near equilibrium despite wide variations in their steady-state concentrations.
Abstract: 1. Free carnitine, acetylcarnitine, short-chain acylcarnitine and acid-insoluble carnitine (probably long-chain acylcarnitine) have been measured in rat tissues. 2. Starvation caused an increase in the proportion of carnitine that was acetylated in liver and kidney; at least in liver fat-feeding had the same effect, whereas a carbohydrate diet caused a very low acetylcarnitine content. 3. In heart, on the other hand, starvation did not cause an increase in the acetylcarnitine/carnitine ratio, whereas fat-feeding caused a decrease. The acetylcarnitine content of heart was diminished by alloxan-diabetes or a fatty diet, but not by re-feeding with carbohydrate. 4. Under conditions of increased fatty acid supply the acid-insoluble carnitine content was increased in heart, liver and kidney. 5. The acylation state of carnitine was capable of very rapid change. Concentrations of carnitine derivatives varied with different methods of obtaining tissue samples, and very little acid-insoluble carnitine was found in tissues of rats anaesthetized with Nembutal. In liver the acetylcarnitine (and acetyl-CoA) content decreased if freezing of tissue samples was delayed; in heart this caused an increase in acetylcarnitine. 6. Incubation of diaphragms with acetate or dl-β-hydroxybutyrate caused the acetylcarnitine content to become elevated. 7. Perfusion of hearts with fatty acids containing an even number of carbon atoms, dl-β-hydroxybutyrate or pyruvate resulted in increased contents of acetylcarnitine and acetyl-CoA. Accumulation of these acetyl compounds was prevented by the additional presence of propionate or pentanoate in the perfusion medium; this prevention was not due to extensive propionylation of CoA or carnitine. 8. Perfusion of hearts with palmitate caused a severalfold increase in the content of acid-insoluble carnitine; this increase did not occur when propionate was also present. 9. Comparison of the acetylation states of carnitine and CoA in perfused hearts suggests that the carnitine acetyltransferase reactants may remain near equilibrium despite wide variations in their steady-state concentrations. This is not the case with the citrate synthase reaction. It is suggested that the carnitine acetyltransferase system buffers the tissue content of acetyl-CoA against rapid changes.
267 citations
Authors
Showing all 119522 results
Name | H-index | Papers | Citations |
---|---|---|---|
Albert Hofman | 267 | 2530 | 321405 |
Zhong Lin Wang | 245 | 2529 | 259003 |
Solomon H. Snyder | 232 | 1222 | 200444 |
Trevor W. Robbins | 231 | 1137 | 164437 |
George Davey Smith | 224 | 2540 | 248373 |
Nicholas J. Wareham | 212 | 1657 | 204896 |
Cyrus Cooper | 204 | 1869 | 206782 |
Eric B. Rimm | 196 | 988 | 147119 |
Martin White | 196 | 2038 | 232387 |
Simon D. M. White | 189 | 795 | 231645 |
Michael Rutter | 188 | 676 | 151592 |
George Efstathiou | 187 | 637 | 156228 |
Mark Hallett | 186 | 1170 | 123741 |
David H. Weinberg | 183 | 700 | 171424 |
Paul G. Richardson | 183 | 1533 | 155912 |