386 research outputs found
Feedbacks and social tipping: A dynamic systems approach to rapid decarbonization
Social tipping points are promising levers for accelerating progress towards net-zero greenhouse gas emission targets. They describe how social, political, economic or technological systems can move rapidly into a new state if cascading positive feedback mechanisms are triggered. Analysing the potential for social tipping requires considering the inherent complexity of social systems and their feedbacks. Here, drawing on insights from an expert elicitation workshop, we outline a dynamic systems approach that entails i) a systems outlook involving interconnected feedback mechanisms alongside cross-system and cross-scale interactions, ii) directed data collection efforts to provide empirical evidence and monitoring of social tipping dynamics, and iii) global, integrated, descriptive modelling to project future dynamics and provide ex-ante evidence for interventions aiming to trigger positive feedback mechanisms. We argue how and why this approach will strengthen the climate policy relevance of research on social tipping
A dynamic systems approach to harness the potential of social tipping
Social tipping points are promising levers to achieve net-zero greenhouse gas emission targets. They describe how social, political, economic or technological systems can move rapidly into a new state if cascading positive feedback mechanisms are triggered. Analysing the potential of social tipping for rapid decarbonization requires considering the inherent complexity of social systems. Here, we identify that existing scientific literature is inclined to a narrative-based account of social tipping, lacks a broad empirical framework and a multi-systems view. We subsequently outline a dynamic systems approach that entails (i) a systems outlook involving interconnected feedback mechanisms alongside cross-system and cross-scale interactions, and including a socioeconomic and environmental injustice perspective (ii) directed data collection efforts to provide empirical evidence for and monitor social tipping dynamics, (iii) global, integrated, descriptive modelling to project future dynamics and provide ex-ante evidence for interventions. Research on social tipping must be accordingly solidified for climate policy relevance
Antideuteron and deuteron production in mid-central Pb+Pb collisions at 158 GeV
Production of deuterons and antideuterons was studied by the NA49 experiment
in the 23.5% most central Pb+Pb collisions at the top SPS energy of
=17.3 GeV. Invariant yields for and were measured
as a function of centrality in the center-of-mass rapidity range .
Results for together with previously published
measurements are discussed in the context of the coalescence model. The
coalescence parameters were deduced as a function of transverse momentum
and collision centrality.Comment: 9 figure
System-size dependence of the pion freeze-out volume as a potential signature for the phase transition to a Quark Gluon Plasma
Hanburry-Brown-Twiss (HBT) correlation functions and radii of negatively
charged pions from C+C, Si+Si, Cu+Cu, and In+In at lower RHIC/SPS energies are
calculated with the UrQMD transport model and the CRAB analyzing program. We
find a minimum in the excitation function of the pion freeze-out volume at low
transverse momenta and around GeV which can be related to
the transition from hadronic to string matter (which might be interpreted as a
pre-cursor of the QGP). The existence of the minimum is explained by the
competition of two mechanisms of the particle production, resonance decays and
string formation/fragmentation.Comment: 12 pages, 4 fig
Measurement of event-by-event transverse momentum and multiplicity fluctuations using strongly intensive measures and in nucleus-nucleus collisions at the CERN Super Proton Synchrotron
Results from the NA49 experiment at the CERN SPS are presented on
event-by-event transverse momentum and multiplicity fluctuations of charged
particles, produced at forward rapidities in central Pb+Pb interactions at beam
momenta 20, 30, 40, 80, and 158 GeV/c, as well as in systems of
different size (, C+C, Si+Si, and Pb+Pb) at 158 GeV/c. This publication
extends the previous NA49 measurements of the strongly intensive measure
by a study of the recently proposed strongly intensive measures of
fluctuations and . In the explored kinematic
region transverse momentum and multiplicity fluctuations show no significant
energy dependence in the SPS energy range. However, a remarkable system size
dependence is observed for both and , with the
largest values measured in peripheral Pb+Pb interactions. The results are
compared with NA61/SHINE measurements in collisions, as well as with
predictions of the UrQMD and EPOS models.Comment: 12 pages, 14 figures, to be submitted to PR
High p_T Spectra of Identified Particles Produced in Pb+Pb Collisions at 158GeV/nucleon Beam Energy
Transverse momentum spectra of pi^{+/-}, p, pbar, K^{+/-}, K^0_s and Lambda
at midrapidity were measured at high p_T in Pb+Pb collisions at 158GeV/nucleon
beam energy by the NA49 experiment. Particle yield ratios (p/pi, K/pi and
Lambda/K^0_s) show an enhancement of the baryon/meson ratio for p_T>2GeV/c. The
nuclear modification factor R_{CP} is extracted and compared to RHIC
measurements and pQCD calculations.Comment: Quark Matter 2005 parallel section proceeding
High p_T Spectra of Identified Particles Produced in Pb+Pb Collisions at 158A GeV Beam Energy
Results of the NA49 collaboration on the production of hadrons with large
transverse momentum in Pb+Pb collisions at 158A GeV beam energy are presented.
A range up to p_T = 4 GeV/c is covered. The nuclear modification factor R_CP is
extracted for pions, kaons and protons, and the baryon to meson ratios p/pi+,
pbar/pi- and Lambda/K^0_s are studied. All results are compared to other
measurements at SPS and RHIC and to theoretical calculations.Comment: Submitted to J. Phys. G (Proceedings of the 9th International
Conference on Strangeness in Quark Matter, Los Angeles, USA, March 26-31,
2006). 5 pages, 3 figure
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