8,250 research outputs found
Environmental impacts of grazed clover/grass pastures
peer-reviwedGrazed clover/grass pastures are important for animal production systems and the clover
component is critical for its contribution to N inputs via biological fixation of atmospheric
N2. The resource efficiency and environmental emissions for clover/grass pastures can
differ from that of N-fertilised grass-only pastures. Fixation of N2 by clover uses photosynthetically-
fixed carbon, whereas fertiliser N production consumes fossil fuels and
has net greenhouse gas (GHG) emissions. Clover has a higher phosphorus (P) requirement
than grass and where extra P fertiliser is used for clover/grass pastures the risk of
P loss to waterways is greater than for grass-only pastures. Nitrogen leaching from
grazed pasture increases exponentially with increased N inputs and urinary-N contributes
70 to 90% of total N leaching. However, the few studies comparing clover/grass and
N-fertilised grass-only pastures at similar total N inputs indicated similar N leaching
losses. Nitrous oxide emissions from grazed pastures due to N-cycling of excreta are
similar for clover/grass and N-fertilised grass-only pastures at similar total N inputs.
However, grass-only pasture requires the application of N fertiliser, which will result in
additional specific losses that donât occur from clover-fixed N. Thus, total N2O emissions
are generally higher for N-fertilised grass pastures than for clover/grass pastures. A summary
of various whole-system and life cycle assessment analyses for dairy farms from
various countries indicated that at similar total N inputs, clover/grass pasture systems
can be more efficient than N-fertilised grass systems per kilogram of milk produced from
an energy use and GHG perspective whereas results for nutrient losses to waterways were
mixed and appear to be similar for both pasture types. In practice, other management
practices on farm, such as crop integration, supplementary feeding strategy and winter
management, can have a larger overall effect on environmental emissions than whether
the N input is derived from fertiliser N or from N2 fixation
Early campaign economic perceptions can help to predict the national verdict on Election Day
It is well known that elections are determined by certain fundamental variables: internal factors that reflect votersâ long-term political predispositions and external factors that are unique to each campaign. Robert S. Erikson and Christopher Wlezien examine how one external factor, the state of the economy, compares to how votersâ internal factors evolve over the final 200 days of presidential campaigns. They find that while noneconomic factors dominate at the outset of the campaign, the economic component increases in salience as Election Day draws nearer and offers greater electoral predictability overall
Equilibria in Campaign Spending Games: Theory and Data
This paper presents a formal game-theoretic model to explain the simultaneity problem that has made it difficult to obtain unbiased estimates of the effects of both incumbent and challenger spending in U.S. House elections. The model predicts a particular form of correlation between the expected closeness of the race and the level of spending by both candidates, which implies that the simultaneity problem should not be present in close races, and should be progressively more severe in range of safe races that are empirically observed. This is confirmed by comparing simple OLS regression of races that are expected to be close with races that are expected not to be close, using House incumbent races spanning two decades. The theory also implies that inclusion of a variable controlling for total spending should successfully produce reliable estimates using OLS. This is confirmed
The Spending Game: Money, Votes, and Incumbency in Congressional Elections
This paper takes a game-theoretic approach to the analysis of the spending-votes relationship in Congressional elections to reinvestigate the surprisingly weak effects of incumbent spending measured in previous studies. Rather than focusing narrowly on the impact of spending on electoral outcomes, we attempt to take account of the reciprocal effect of (anticipated) closeness on spending using several statistical approaches. We also offer improvements in the specification and measurement of the vote equation, by using a better measure of district party strength adjusted for year-effects, and by including a variable that measures the heat of the campaign in terms of total spending by the incumbents and challengers. The latter measure partially corrects for the simultaneously determined (and highly positively correlated) levels of incumbent and challenger spending. A more rigorous multiequation simultaneous equations model, identified by uncorrelated errors, provides even more leverage for sorting out the effects of incumbent and challenger spending on votes. That analysis indicates (in a complete turnaround from findings reported elsewhere) that incumbent spending effects are highly significant and of a magnitude that is, if anything, greater than challenger spending effects. The paper concludes by using a game theoretic model to estimate the effect of anticipated closeness on spending and to estimate differences in campaign financing costs between incumbents and challengers
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Forecasting House Seats from General Congressional Polls
According to the frequent polling on the generic ballot for Congress, the Democrats hold a large advantage leading up to the vote on November 7. But does this Democratic edge mean that the Democrats will win a majority of House seats? Doubts are often expressed about the accuracy of the generic ballot polls. And even if the polls are correct in indicating a majority of votes going to Democratic candidates, further doubts are expressed about whether the Democrats' vote margin will be sufficient to win the most seats. This paper is intended to provide some guidance for translating the results of generic congressional polls into the election outcome
National polls and district information point to a 10 seat GOP midterm swing in the House to 244 seats
This midterm cycle, much commentary has been focused on Senate races, given that the Republican Party looks very likely to hold and increase its seats in the House of Representatives. But how many House seats should the GOP expect to win? With a week to go, Joseph Bafumi, Robert S. Erikson, and Christopher Wlezien give an updated House forecast. They write that a combination of the GOPâs incumbency advantage, their domination of state legislatures (and thus, redistricting) since 2010, and U.S. internal migration, mean that the Republican Party are likely to win about 244 seats on November 4th
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Forecasting House Seats from General Congressional Polls
According to the frequent polling on the generic ballot for Congress, the Democrats hold a large advantage leading up to the vote on November 7. But does this Democratic edge mean that the Democrats will win a majority of House seats? Doubts are often expressed about the accuracy of the generic ballot polls. And even if the polls are correct in indicating a majority of votes going to Democratic candidates, further doubts are expressed about whether the Democrats' vote margin will be sufficient to win the most seats. This paper is intended to provide some guidance for translating the results of generic congressional polls into the election outcome
Psychosocial issues for adolescent and young adult cancer patients in a global context: A forwardâlooking approach
The first decade of adolescent and young adult (AYA) oncology psychosocial care and research (2005â2015) was driven by a normative, developmental framework that assumed a generalizable life experience for AYAs that is distinct from both younger children and older adults. As we proceed through a second decade, new considerations emerge regarding diversity of life experiences as occurring within and influenced by a complex global context. The purpose of this paper is to review and provide commentary on the impact of global and contextual conditions on AYAs. We expound upon the effects of precarious labor conditions, changing timetables and priorities for developmental tasks, sexual and gender plurality, and expanding cultural diversity. We discuss the implications of social genomics and technology and social media for enhancing precision psychosocial medicine. To build a forwardâlooking approach, this paper calls for tailored, multilevel treatments that consider variability of AYAs within the social and global contexts in which they live.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149735/1/pbc27789_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149735/2/pbc27789.pd
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