5,876 research outputs found
Energy Correlation Functions for Jet Substructure
We show how generalized energy correlation functions can be used as a
powerful probe of jet substructure. These correlation functions are based on
the energies and pair-wise angles of particles within a jet, with (N+1)-point
correlators sensitive to N-prong substructure. Unlike many previous jet
substructure methods, these correlation functions do not require the explicit
identification of subjet regions. In addition, the correlation functions are
better probes of certain soft and collinear features that are masked by other
methods. We present three Monte Carlo case studies to illustrate the utility of
these observables: 2-point correlators for quark/gluon discrimination, 3-point
correlators for boosted W/Z/Higgs boson identification, and 4-point correlators
for boosted top quark identification. For quark/gluon discrimination, the
2-point correlator is particularly powerful, as can be understood via a
next-to-leading logarithmic calculation. For boosted 2-prong resonances the
benefit depends on the mass of the resonance.Comment: 45 pages, 28 figures, update to JHEP version, some minor typos fixed,
added discussion at end of section
Dynamic Phase Transitions in Cell Spreading
We monitored isotropic spreading of mouse embryonic fibroblasts on
fibronectin-coated substrates. Cell adhesion area versus time was measured via
total internal reflection fluorescence microscopy. Spreading proceeds in
well-defined phases. We found a power-law area growth with distinct exponents
a_i in three sequential phases, which we denote basal (a_1=0.4+-0.2), continous
(a_2=1.6+-0.9) and contractile (a_3=0.3+-0.2) spreading. High resolution
differential interference contrast microscopy was used to characterize local
membrane dynamics at the spreading front. Fourier power spectra of membrane
velocity reveal the sudden development of periodic membrane retractions at the
transition from continous to contractile spreading. We propose that the
classification of cell spreading into phases with distinct functional
characteristics and protein activity patterns serves as a paradigm for a
general program of a phase classification of cellular phenotype. Biological
variability is drastically reduced when only the corresponding phases are used
for comparison across species/different cell lines.Comment: 4 pages, 5 figure
Physical and magnetic properties of Ba(FeRu)As single crystals
Single crystals of Ba(FeRu)As, , have been grown
and characterized by structural, magnetic and transport measurements. These
measurements show that the structural/magnetic phase transition found in pure
BaFeAs at 134 K is suppressed monotonically by Ru doping, but, unlike
doping with TM=Co, Ni, Cu, Rh or Pd, the coupled transition seen in the parent
compound does not detectably split into two separate ones. Superconductivity is
stabilized at low temperatures for and continues through the highest
doping levels we report. The superconducting region is dome like, with maximum
T ( K) found around . A phase diagram of temperature
versus doping, based on electrical transport and magnetization measurements,
has been constructed and compared to those of the
Ba(FeTM)As (TM=Co, Ni, Rh, Pd) series as well as to the
temperature-pressure phase diagram for pure BaFeAs. Suppression of the
structural/magnetic phase transition as well as the appearance of
superconductivity is much more gradual in Ru doping, as compared to Co, Ni, Rh
and Pd doping, and appears to have more in common with BaFeAs tuned
with pressure; by plotting and as a function of changes in unit
cell dimensions, we find that changed in the ratio, rather than changes
in , or V, unify the and phase diagrams for BaFeAs
and Ba(FeRu)As respectively.Comment: 16 pages, 10 figure
Natural flood management: Opportunities to implement nature‐based solutions on privately owned land
The implementation of Natural Flood Management (NFM), as an example of a nature‐based solution (NbS), is promoted as a risk reduction strategy to support sustainable flood risk management and climate change adaptation more widely. Additionally, as an NbS, NFM aims to provide further multiple benefits, such as increased biodiversity and improved water quality as well as improved mental health. The implementation of NbS often needs private‐owned or managed land, yet can create conflicts between the different stakeholders which can undermine the social consensus required for successful implementation. Consequently, a main question is how the multiple benefits and requirements of NFM can be delivered to meet the different goals of the wide variety of stakeholders who must be involved. This article discusses the challenges and potential of implementing NFM as an alternative to the traditional technical mitigation measures in flood risk management. We outline four opportunities in the implementation of NFM: physical conditions of the catchment, social interaction, financial resources, and institutional setting. Their importance is then demonstrated and compared to different examples across the globe. Nevertheless, the core drivers reflect the social interaction and institutional setting and the role of stakeholders in the successful implementation of NFM
Reference Distorted Prices
I show that when consumers (mis)perceive prices relative to reference prices,
budgets turn out to be soft, prices tend to be lower and the average quality of
goods sold decreases. These observations provide explanations for decentralized
purchase decisions, for people being happy with a purchase even when they have
paid their evaluation, and for why trade might affect high quality local firms
'unfairly'
Effect of electron irradiation on superconductivity in single crystals of Ba(FeRu)As (0.24)
A single crystal of isovalently substituted Ba(FeRu)As
() was sequentially irradiated with 2.5 MeV electrons up to a maximum
dose of electrons/cm^2. The electrical resistivity was
measured \textit{in - situ} at 22 K during the irradiation and \textit{ex -
situ} as a function of temperature between subsequent irradiation runs. Upon
irradiation, the superconducting transition temperature, , decreases and
the residual resistivity, , increases. We find that electron
irradiation leads to the fastest suppression of compared to other types
of artificially introduced disorder, probably due to the strong short-range
potential of the point-like irradiation defects. A more detailed analysis
within a multiband scenario with variable scattering potential strength shows
that the observed vs. is fully compatible with pairing,
in contrast to earlier claims that this model leads to a too rapid a
suppression of with scattering
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