11,658 research outputs found
Azimuthal angular correlations between heavy-flavour decay electrons and charged hadrons in pp collisions at TeV in ALICE
In ultra-relativistic heavy-ion collisions heavy quarks (charm and beauty)
are produced in hard scattering processes and thus carry relevant information
on the properties of the created hot and dense medium. Heavy-flavour hadrons
can be measured using electrons from their semileptonic decay channels. The
relative contribution of charm and beauty hadrons can be estimated from the
study of the near side azimuthal angular correlations between these electrons
and charged hadrons.
We present the measurement of azimuthal angular correlations between
electrons and charged hadrons in pp collisions at 2.76 TeV measured with ALICE
at the LHC. Electrons are identified using the Electromagnetic Calorimeter and
the Time Projection Chamber and the charged hadrons are identified using the
Time Projection Chamber. The azimuthal angular correlation distributions from
PYTHIA simulations are used to extract the relative contribution from B-hadron
decays to the yield of electrons from heavy-flavour decays up to
= 10 GeV/c
Gatting the New Climate Treaty Right: Leveraging Energy Subsidies to Promote Multilateralism
In a previous paper, Trading Up Kyoto: A Proposal for Amending the Protocol, I argued that not only do international trade rules, specifically the operation of the World Trade Organization ( WTO ) agreements, hinder international climate change treaty negotiations, but also that applying exceptions to circumvent trade rules is doctrinally difficult and normatively unsettling, primarily because of WTO jurisprudence, the colorable intent of nations that are violating WTO rules in the guise of mitigating climate change, and the challenges to creating environmental exceptions to trade rules to facilitate emissions reduction. To illustrate this point, I focused on ongoing trade disputes involving a few renewable energy subsidies through which some nations are apparently seeking to reduce their emissions. I then argued that an effective climate change treaty should counteract the impact of trade and trade rules. In this Article, I argue that nations should negotiate a plan to phase out harmful subsidies, particularly fossil fuel subsidies. The idea of eliminating subsidies is not new. It has been considered an important solution to reduce greenhouse gas emissions, and one that can complement WTO rules. This Article adds another dimension to this solution, i.e. leveraging subsidies within the new climate change treaty to encourage multilateralism. Multilateralism is essential to address the leakage and competition problems arising from the nonparticipation of all major greenhouse gas emitters. Effective unilateral measures to counter leakage violate WTO rules. I argue that nations can counteract this problem by incorporating into the new climate change treaty a mechanism to phase out harmful subsidies in exchange for a right to provide beneficial subsidies as one policy tool that would promote climate change mitigation efforts significantly. This proposal would complement, and not replace, existing provisions; would comply with WTO rules; would mimic other international environmental treaties, notably CITES, the Basel Convention, and the Montreal Protocol, which have addressed tensions between trade and an environmental problem by incorporating trade measures within the treaty
Azimuthal angular correlations between heavy-flavour decay particles and charged hadrons in pp collisions in ALICE
Heavy quarks produced in pp and heavy ion collisions are studied using
heavy-flavour decay electrons and heavy-flavour mesons. Detailed understanding
of the production processes and fragmentation of heavy quarks can be obtained
by studying the azimuthal angular correlation of heavy-flavour hadrons. The
azimuthal angular correlations of heavy-flavour mesons and charged hadrons can
be used to disentangle charm and beauty-hadrons in pp collisions. In this
contribution the fraction of electrons from beauty-hadron decays in the
heavy-flavour decay electron yield is shown as well as the beauty production
cross section in pp collisions at = 2.76 TeV. The
measurements are compared to the predictions from next-to leading order
perturbative QCD calculations. We also show the results from correlation
analysis of charged mesons and hadrons performed using pp
collision data at = 7 TeV.Comment: Hot Quarks 2012 proceeding
Measurement of electrons from heavy-flavour decays in Pb-Pb collisions at TeV with ALICE
The measurement of heavy-flavour (charm and beauty) production in
ultra-relativistic heavy-ion collisions provides an important contribution to
the study of the properties of the hot and dense medium created in such
collisions. One approach to measure heavy-flavour production is via electrons
from semi-leptonic decays of heavy-flavour hadrons. In this contribution we
present the nuclear modification factor and the azimuthal
anisotropy of heavy-flavour decay electrons in Pb-Pb collisions at
TeV, which are sensitive to the interaction
of c and b quarks with the medium. We also present, for the first time, the
azimuthal angular correlations of heavy-flavour decay electrons and charged
hadrons, , in Pb-Pb collisions and the
corresponding near-side yield ratio .Comment: 4 pages, Strange Quark Matter conference proceedin
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The Stabilizing Effect Of Intraspecific Genetic Variation On Population Dynamics In Novel And Ancestral Habitats
Recent studies show that intraspecific genetic variation in asexual species may have large effects on community and ecosystem functions, increasing their stability, productivity, and species richness. However, major questions regarding its population-level impact remain empirically unanswered: (a) How does intraspecific genetic diversity affect the ecological characteristics of sexual species, in which recombination can alter the outcome of causal mechanisms such as selection and niche diversification? (b) Does genetic diversity increase population dynamic stability? (c) Is the impact of genetic diversity dependent on the selective environment? To answer these questions, I founded replicate flour beetle (Tribolium castaneum) populations with different degrees of ecologically relevant, heritable trait variation and monitored their dynamics for approximately eight generations. I show that population stability and persistence increased with greater genetic variation but that the stabilizing effect was independent of the selective habitat (different proportions of ancestral and novel resources). Alleles from a single founding strain underwent a selective sweep in the homogeneous ancestral habitat but not in a novel heterogeneous habitat. These results expand current understanding of the ecological impacts of genetic diversity by showing that genetically more diverse sexual populations persist longer and are more stable but that the selective environment determines the mechanistic basis of increased stability.Integrative Biolog
Bonds and bridges : social and poverty
Using the lens of social capital-especially bridging or cross-cutting ties that cut across social groups and between social groups and government-provides new insights into policy design. Solidarity within social groups creates ties (bonding social capital) that bring people and resources together. In unequal societies, ties that cut across groups (bridging social capital) are essential for social cohesion and for poverty reduction. The nature of interaction between state and society is characterized as complementarity and substitution. When states are functional, the informal and formal work well together-for example, government support or community-based development. When states become dysfunctional, the informal institutions become a substitute and are reduced to serving a defensive or survival function. To move toward economic and social well-being, states must support inclusive development. Investments in the organizational capacity of the poor are critical. Interventions are also required to foster bridging ties across social groups-ethnic, religious, caste, or racial groups. Such interventions can stem from the state, private sector, or civil society and include: Changes in rules to include groups previously excluded from formal systems of finance, education, and governance, at all levels. Political pluralism and citizenship rights. Fairness before the law for all social groups together. Infrastructure that eases communication. Education, media, and public information policies that reinforce norms and values of tolerance and diversity.Social Capital,Public Health Promotion,Education and Society,Decentralization,Community Development and Empowerment,Poverty Assessment,National Governance,Governance Indicators,Social Capital,Community Development and Empowerment
A Requirement for Fatty Acid Oxidation in the Hormone-Induced Meiotic Maturation of Mouse Oocytes
We have previously shown that fatty acid oxidation (FAO) is required for AMP-activated protein kinase (PRKA)-induced maturation in vitro. In the present study, we have further investigated the role of this metabolic pathway in hormone-induced meiotic maturation. Incorporating an assay with 3H-palmitic acid as the substrate, we first examined the effect of PRKA activators on FAO levels. There was a significant stimulation of FAO in cumulus cell-enclosed oocytes (CEO) treated with 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) and RSVA405. In denuded oocytes (DO), AICAR stimulated FAO only in the presence of carnitine, the molecule that facilitates fatty acyl CoA entry into the mitochondria. The carnitine palmitoyltransferase 1 activator C75 successfully stimulated FAO in CEO. All three of these activators trigger germinal vesicle breakdown. Meiotic resumption induced by follicle-stimulating hormone (FSH) or amphiregulin was completely inhibited by the FAO inhibitors etomoxir, mercaptoacetate, and malonyl CoA. Importantly, FAO was increased in CEO stimulated by FSH and epidermal growth factor, and this increase was blocked by FAO inhibitors. Moreover, compound C, a PRKA inhibitor, prevented the FSH-induced increase in FAO. Both carnitine and palmitic acid augmented hormonal induction of maturation. In a more physiological setting, etomoxir eliminated human chorionic gonadotropin (hCG)-induced maturation in follicle-enclosed oocytes. In addition, CEO and DO from hCG-treated mice displayed an etomoxir-sensitive increase in FAO, indicating that this pathway was stimulated during in vivo meiotic resumption. Taken together, our data indicate that hormone-induced maturation in mice requires a PRKA-dependent increase in FAO
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