University of Missouri

About: University of Missouri is a education organization based out in Columbia, Missouri, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 41427 authors who have published 83598 publications receiving 2911437 citations. The organization is also known as: Mizzou & Missouri-Columbia.

Reconciling carbon-cycle concepts, terminology, and methods

Abstract: Recent projectionsofclimatic change havefocused a great deal of scientific and public attention on patterns of carbon (C) cycling as well as its controls, particularly the factors that determine whether an ecosystem is a net source or sink of atmospheric carbon dioxide (CO2). Net ecosystem production (NEP), a central concept in C-cycling research, has been used by scientists to represent two different concepts. We propose that NEP be restricted to just one of its two original definitions—the imbalance between gross primary production (GPP) and ecosystem respiration (ER). We further propose that a new term—net ecosystem carbon balance (NECB)—be applied to the net rate of C accumulation in (or loss from [negative sign]) ecosystems. Net ecosystem carbon balance differs from NEP when C fluxesotherthanCfixationandrespiration occur,or when inorganic C enters or leaves in dissolved form. These fluxes include the leaching loss or lateral transfer of C from the ecosystem; the emission of volatile organic C, methane, and carbon monoxide; and the release of soot and CO2 from fire. Carbon fluxes in addition to NEP are particularly important determinants of NECB over long time scales. However, even over short time scales, they are important in ecosystems such as streams, estuaries, wetlands, and cities. Recent technological advances have led to a diversity of approaches to the measurement of C fluxes at different temporal and spatial scales. These approaches frequently capture different components of NEP or NECB and can therefore be compared across scales only by carefully specifying the

Recent Antarctic ice mass loss from radar interferometry and regional climate modelling

Abstract: Observed estimates of ice losses in Antarctica combined with regional modelling of ice accumulation in the interior suggest that East Antarctica is close to a balanced mass budget, but large losses of ice occur in the narrow outlet channels of West Antarctic glaciers and at the northern tip of the Antarctic peninsula.

Large Effects from Small Exposures. III. Endocrine Mechanisms Mediating Effects of Bisphenol A at Levels of Human Exposure

Abstract: Over 6 billion pounds per year of the estrogenic monomer bisphenol A (BPA) are used to manufacture polycarbonate plastic products, in resins lining metal cans, in dental sealants, and in blends with other types of plastic products. The ester bond linking BPA molecules in polycarbonate and resins undergoes hydrolysis, resulting in the release of free BPA into food, beverages, and the environment, and numerous monitoring studies now show almost ubiquitous human exposure to biologically active levels of this chemical. BPA exerts estrogenic effects through the classical nuclear estrogen receptors, and BPA acts as a selective estrogen receptor modulator. However, BPA also initiates rapid responses via estrogen receptors presumably associated with the plasma membrane. Similar to estradiol, BPA causes changes in some cell functions at concentrations between 1 pM and 1 nM, and the mean and median range of unconjugated BPA measured by multiple techniques in human pregnant maternal, fetal, and adult blood and other tissues exceeds these levels. In contrast to these published findings, BPA manufacturers persist in describing BPA as a weak estrogen and insist there is little concern with human exposure levels. Our concern with human exposure to BPA derives from 1) identification of molecular mechanisms mediating effects in human and animal tissues at very low doses, 2) in vivo effects in experimental animals caused by low doses within the range of human exposure, and 3) widespread human exposure to levels of BPA that cause adverse effects in animals.

A Measure of Media Bias

Abstract: In this paper we estimate ADA (Americans for Democratic Action) scores for major media outlets such as the New York Times, USA Today, Fox News Special Report, and all three network television news shows. Our estimates allow us to answer such questions as Is the average article in the New York Times more liberal than the average speech by Tom Daschle? or Is the average story on Fox News more conservative than the average speech by Bill Frist? To compute our measure, we count the times that a media outlet cites various think tanks and other policy groups. We compare this with the times that members of Congress cite the same groups in their speeches on the floor of the House and Senate. By comparing the citation patterns we construct an ADA score. As a simplified example, imagine that there were only two think tanks, and suppose that the New York Times cited the first think tank twice as often as the second. Our method asks: What is the typical ADA score of members of Congress who exhibit the same frequency (2:1) in their speeches? This is the score that we would assign to the New York Times. Our results show a strong liberal bias. All of the news outlets except Fox News Special Report and the Washington Times received a score to the left of the average member of Congress. Consistent with many conservative critics, CBS Evening News and the New York Times received a score far left of center. Outlets such as USA Today, NPRs Morning Edition, NBCs Nightly News and ABCs World News Tonight were moderately left. The most centrist outlets (but still left-leaning) by our measure were the Newshour with Jim Lehrer, CNNs NewsNight with Aaron Brown, and ABCs Good Morning America. Fox News Special Report, while right of center, was closer to the center than any of the three major networks evening news broadcasts. All of our findings refer strictly to the news stories of the outlets. That is, we omitted editorials, book reviews, and letters to the editor from our sample.