A measurement is presented of the charged hadron multiplicity in hadronic PbPb collisions, as a function of pseudorapidity and centrality, at a collision energy of 2.76 TeV per nucleon pair. The data ...sample is collected using the CMS detector and a minimum-bias trigger, with the CMS solenoid off. The number of charged hadrons is measured both by counting the number of reconstructed particle hits and by forming hit doublets of pairs of layers in the pixel detector. The two methods give consistent results. The charged hadron multiplicity density dN(ch)/d eta, evaluated at eta=0 for head-on collisions, is found to be 1612 +/- 55, where the uncertainty is dominated by systematic effects. Comparisons of these results to previous measurements and to various models are also presented.
First measurements of dihadron correlations for charged particles are presented for central PbPb collisions at a nucleon-nucleon center-of-mass energy of 2.76 TeV over a broad range in relative ...pseudorapidity, Delta(eta), and the full range of relative azimuthal angle, Delta(phi). The data were collected with the CMS detector, at the LHC. A broadening of the away-side (Delta(phi) approximately pi) azimuthal correlation is observed at all Delta(eta), as compared to the measurements in pp collisions. Furthermore, long-range dihadron correlations in Delta(eta) are observed for particles with similar phi values. This phenomenon, also known as the "ridge", persists up to at least |Delta(eta)| = 4. For particles with transverse momenta (pt) of 2-4 GeV/c, the ridge is found to be most prominent when these particles are correlated with particles of pt = 2-6 GeV/c, and to be much reduced when paired with particles of pt = 10-12 GeV/c.
Climate change impacts on agriculture have been intensifying in the Northeastern United States. In order to encourage the adoption of climate change adaptation and mitigation practices by farmers, it ...is critical to understand their perspectives on the risks they face and actions they are taking. However, very few empirical studies have considered how farmers are interpreting and responding to climate impacts, risks and opportunities in the Northeast. This study investigates farmer views and decisions related to climate change using data from six farmer focus groups conducted across New York and Pennsylvania. The study examined how farmers perceived climate impacts on their farms, the practices they are willing to adopt, and how perceived risks and vulnerability affect farmers’ decision-making related to adaptation and mitigation strategies. Although farmers articulated concern regarding climate impacts, they also made clear that other business pressures, such as profitability, market conditions, labor availability or government regulations were often more critical issues that affected their decision-making. Decisions about adopting climate change adaptation and mitigation practices vary widely, and personal experience with extreme weather and changing seasons affected decision-making. The findings from this study provide improved understanding of farmers’ needs and priorities, which can help guide land-grant researchers, extension and policymakers in their efforts to develop and coordinate a comprehensive strategy to address climate change impacts on agriculture in the Northeast.
The photoisomerization reaction of a fluorescent protein chromophore occurs on the ultrafast timescale. The structural dynamics that result from femtosecond optical excitation have contributions from ...vibrational and electronic processes and from reaction dynamics that involve the crossing through a conical intersection. The creation and progression of the ultrafast structural dynamics strongly depends on optical and molecular parameters. When using X-ray crystallography as a probe of ultrafast dynamics, the origin of the observed nuclear motions is not known. Now, high-resolution pump-probe X-ray crystallography reveals complex sub-ångström, ultrafast motions and hydrogen-bonding rearrangements in the active site of a fluorescent protein. However, we demonstrate that the measured motions are not part of the photoisomerization reaction but instead arise from impulsively driven coherent vibrational processes in the electronic ground state. A coherent-control experiment using a two-colour and two-pulse optical excitation strongly amplifies the X-ray crystallographic difference density, while it fully depletes the photoisomerization process. A coherent control mechanism was tested and confirmed the wave packets assignment.
Climate change has serious implications for agricultural production, natural resource management, and food security. In the United States, land-grant universities and the U.S. Cooperative Extension ...System have a critical role to play in conducting basic and applied research related to climate change and translating findings into meaningful programming. However, land-grant universities and Extension have had difficulty maintaining their roles as the preeminent source of trusted information on complex topics like climate change. To help guide research and programming agendas of land-grant universities, the authors explored the barriers and priorities that researchers and Extension personnel at 16 northeastern land-grant universities perceive as they pursue climate change research and programming. Through an online survey, respondents indicated their perceptions of barriers related to information, workplace, and target audiences as well as the priorities they perceived as most important for land-grant universities to pursue. Statistical analysis indicated that lack of funding, lack of time, lack of locally relevant climate information, and challenges with target audiences were among the most critical barriers. In terms of future priorities, respondents indicated securing funding for applied research, training Extension educators, and developing locally relevant decision support tools as the most important activities northeastern land-grant universities can undertake. Based on these findings, this study concludes that land-grant universities will need to strategically pursue research and educational programming on climate change in ways that integrate research and Extension and simultaneously address climate change and other concerns of land managers.
Climate change impacts on agriculture have been intensifying in the Northeastern and Midwestern United States. Few empirical studies have considered how dairy farmers and/or their advisors are ...interpreting and responding to climate impacts, risks, and opportunities in these regions. This study investigates dairy farmer and advisor views and decisions related to climate change using data from seven farmer and advisor focus groups conducted in New York and Wisconsin. The study examined how farmers and advisors perceived climate impacts on dairy farms, the practices they are adopting, and how perceived risks and vulnerability affect farmers’ decision making related to adaptation strategies. Although dairy farmers articulated concern regarding climate impacts, other business pressures, such as profitability, market conditions, government regulations, and labor availability were often more critical issues that affected their decision making. Personal experience with extreme weather and seasonal changes affected decision making. The findings from this study provide improved understanding of farmers’ needs and priorities, which can help guide land-grant researchers, Extension, and policymakers in their efforts to develop and coordinate a comprehensive strategy to address climate change impacts on dairy in the Northeast and the Midwest US.
Climate change has serious implications for agricultural production, natural resource management, and food security. In the United States, land-grant universities and the U.S. Cooperative Extension ...System have a critical role to play in conducting basic and applied research related to climate change and translating findings into meaningful programming. However, land-grant universities and Extension have had difficulty maintaining their roles as the preeminent source of trusted information on complex topics like climate change. To help guide research and programming agendas of land-grant universities, the authors explored the barriers and priorities that researchers and Extension personnel at 16 northeastern land-grant universities perceive as they pursue climate change research and programming. Through an online survey, respondents indicated their perceptions of barriers related to information, workplace, and target audiences as well as the priorities they perceived as most important for land-grant universities to pursue. Statistical analysis indicated that lack of funding, lack of time, lack of locally relevant climate information, and challenges with target audiences were among the most critical barriers. In terms of future priorities, respondents indicated securing funding for applied research, training Extension educators, and developing locally relevant decision support tools as the most important activities northeastern land-grant universities can undertake. Based on these findings, this study concludes that land-grant universities will need to strategically pursue research and educational programming on climate change in ways that integrate research and Extension and simultaneously address climate change and other concerns of land managers.
Extension is responding to climate change through programming intended to encourage adaptation and mitigation in agricultural production and natural resources management. However, effectively ...engaging target audiences requires identifying appropriate delivery methods. We conducted a study to identify delivery methods researchers and Extension professionals at land-grant universities in the northeastern United States perceive as useful for climate change outreach. Respondents viewed all delivery methods as only slightly useful, though traditional options, including face-to-face interactions and the use of videos and websites, were perceived as slightly more useful than other delivery methods. Therefore, we in Extension must experiment with various delivery methods to identify those most likely to effect the adoption of adaptation and mitigation practices.
Cosmological relaxation of the electroweak scale via Higgs-axion interplay, named as relaxion mechanism, provides a dynamical solution to the Higgs mass hierarchy. In the original proposal by Graham, ...Kaplan and Rajendran, the relaxion abundance today is too small to explain the dark matter of the universe because of the high suppression of the misalignment angle after inflation. It was then realised by Banerjee, Kim and Perez that reheating effects can displace the relaxion, thus enabling it to account for the dark matter abundance from the misalignment mechanism. However, this scenario is realised in a limited region of parameter space to avoid runaway. We show that in the regime where inflationary fluctuations dominate over the classical slow-roll, the "stochastic misalignment" of the field due to fluctuations can be large. We study the evolution of the relaxion after inflation, including the high-temperature scenario, in which the barriers of the potential shrink and destabilise temporarily the local minimum. We open new regions of parameter space where the relaxion can naturally explain the observed dark matter density in the universe, towards larger coupling, larger mass, larger mixing angle, smaller decay constant, as well as larger scale of inflation.
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