508 research outputs found
Decompositions of wage inequality and growth in an advanced economy open to trade
We explore the uses of double-calibrated general equilibrium models as a decomposition tool for analysing contributory factors in the growth and increasing wage inequality in an advanced economy (the UK) since 1979. Calibration of a model to start and end years, based upon an assumed functional form and parameter values, produces a consistent set of decompositions for both growth and inequality. Calibrated TFP growth is consistent with the results from nonparametric growth accounting. The calibration procedure also allows us to explore different exogeneity assumptions regarding capital. However, there are more problems to modelling inequality than with growth: in particular, the main models in the literature, which take skill endowments as given, are characteristically unstable. This strongly emphasises the need for a more dynamic modelling technique, particularly regarding the skill acquisition decision and potential labour market mismatch issues
A high-altitude peatland record of environmental changes in the NW Argentine Andes (24 ° S) over the last 2100 years
High-altitude cushion peatlands are versatile archives for high-resolution palaeoenvironmental studies, due to their high accumulation rates, range of proxies, and sensitivity to climatic and/or human-induced changes. Especially within the Central Andes, the knowledge about climate conditions during the Holocene is limited. In this study, we present the environmental and climatic history for the last 2100 years of Cerro Tuzgle peatland (CTP), located in the dry Puna of NW Argentina, based on a multi-proxy approach. X-ray fluorescence (XRF), stable isotope and element content analyses (δ13C, δ15N, TN and TOC) were conducted to analyse the inorganic geochemistry throughout the sequence, revealing changes in the peatlands' past redox conditions. Pollen assemblages give an insight into substantial environmental changes on a regional scale. The palaeoclimate varied significantly during the last 2100 years. The results reflect prominent late Holocene climate anomalies and provide evidence that in situ moisture changes were coupled to the migration of the Intertropical Convergence Zone (ITCZ). A period of sustained dry conditions prevailed from around 150 BC to around AD 150. A more humid phase dominated between AD 200 and AD 550. Afterwards, the climate was characterised by changes between drier and wetter conditions, with droughts at around AD 650-800 and AD 1000-1100. Volcanic forcing at the beginning of the 19th century (1815 Tambora eruption) seems to have had an impact on climatic settings in the Central Andes. In the past, the peatland recovered from climatic perturbations. Today, CTP is heavily degraded by human interventions, and the peat deposit is becoming increasingly susceptible to erosion and incision.Fil: Schittek, Karsten. University of Heidelberg; Alemania. Universitat Zu Köln; AlemaniaFil: Kock, Sebastian T.. University of Heidelberg; Alemania. Research Center Jülich; AlemaniaFil: Lücke, Andreas. Helmholtz Gemeinschaft. Forschungszentrum Jülich; AlemaniaFil: Hense, Jonathan. Universitaet Bonn; AlemaniaFil: Ohlendorf, Christian. Universitat Bremen; AlemaniaFil: Kulemeyer, Julio José. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Jujuy. Universidad Nacional de Jujuy. Centro de Investigaciones y Transferencia de Jujuy; ArgentinaFil: Lupo, Liliana Concepcion. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Jujuy. Universidad Nacional de Jujuy. Centro de Investigaciones y Transferencia de Jujuy; ArgentinaFil: Schäbitz, Frank. Universitat Zu Köln; Alemani
A New Derivation of the CPT and Spin-Statistics Theorems in Non-Commutative Field Theories
We propose an alternative axiomatic description for non-commutative field
theories (NCFT) based on some ideas by Soloviev to nonlocal quantum fields. The
local commutativity axiom is replaced by the weaker condition that the fields
commute at sufficiently large spatial separations, called asymptotic
commutativity, formulated in terms of the theory of analytic functionals. The
question of a possible violation of the CPT and Spin-Statistics theorems caused
by nonlocality of the commutation relations
is investigated. In spite of this
inherent nonlocality, we show that the modification aforementioned is
sufficient to ensure the validity of these theorems for NCFT. We restrict
ourselves to the simplest model of a scalar field in the case of only
space-space non-commutativity.Comment: The title is new, and the analysis in the manuscript has been made
more precise. This revised version is to be published in J.Math.Phy
Methods and a research agenda for the evaluation of event sequence visualization techniques
The present paper asks how can visualization help data scientists make sense of event sequences, and makes three main contributions. The first is a research agenda, which we divide into methods for presentation, interaction & computation, and scale-up. Second, we introduce the concept of Event Maps to help with scale-up, and illustrate coarse-, medium- and fine-grained Event Maps with electronic health record (EHR) data for prostate cancer. Third, in an experiment we investigated participants’ ability to judge the similarity of event sequences. Contrary to previous research into categorical data, color and shape were better than position for encoding event type. However, even with simple sequences (5 events of 3 types in the target sequence), participants only got 88% correct despite averaging 7.4 seconds to respond. This indicates that simple visualization techniques are not effective
Neutron-induced background in the CONUS experiment
CONUS is a novel experiment aiming at detecting elastic neutrino nucleus
scattering in the fully coherent regime using high-purity Germanium (Ge)
detectors and a reactor as antineutrino () source. The detector setup
is installed at the commercial nuclear power plant in Brokdorf, Germany, at a
very small distance to the reactor core in order to guarantee a high flux of
more than 10/(scm). For the experiment, a good
understanding of neutron-induced background events is required, as the neutron
recoil signals can mimic the predicted neutrino interactions. Especially
neutron-induced events correlated with the thermal power generation are
troublesome for CONUS. On-site measurements revealed the presence of a thermal
power correlated, highly thermalized neutron field with a fluence rate of
(74530)cmd. These neutrons that are produced by nuclear
fission inside the reactor core, are reduced by a factor of 10 on
their way to the CONUS shield. With a high-purity Ge detector without shield
the -ray background was examined including highly thermal power
correlated N decay products as well as -lines from neutron
capture. Using the measured neutron spectrum as input, it was shown, with the
help of Monte Carlo simulations, that the thermal power correlated field is
successfully mitigated by the installed CONUS shield. The reactor-induced
background contribution in the region of interest is exceeded by the expected
signal by at least one order of magnitude assuming a realistic ionization
quenching factor of 0.2.Comment: 28 pages, 28 figure
Nonlinear Quantum Mechanics and Locality
It is shown that, in order to avoid unacceptable nonlocal effects, the free
parameters of the general Doebner-Goldin equation have to be chosen such that
this nonlinear Schr\"odinger equation becomes Galilean covariant.Comment: 10 pages, no figures, also available on
http://www.pt.tu-clausthal.de/preprints/asi-tpa/012-97.htm
Non-Localizability and Asymptotic Commutativity
The mathematical formalism commonly used in treating nonlocal highly singular
interactions is revised. The notion of support cone is introduced which
replaces that of support for nonlocalizable distributions. Such support cones
are proven to exist for distributions defined on the Gelfand-Shilov spaces
, where . This result leads to a refinement of previous
generalizations of the local commutativity condition to nonlocal quantum
fields. For string propagators, a new derivation of a representation similar to
that of K\"{a}llen-Lehmann is proposed. It is applicable to any initial and
final string configurations and manifests exponential growth of spectral
densities intrinsic in nonlocalizable theories.Comment: This version is identical to the initial one whose ps and pdf files
were unavailable, with few corrections of misprint
Alternatives to slash-and-burn agriculture: a research approach for the development of a chop-and-mulch system.
The introduction of research-based innovations into traditional land-use systems is difficult, as examples from agroforestry have ShOWD.It can take years to decades until a new agricultural practice has been adopted by the farmers and often the innovations are not very well aligned with the problems and concems of the farmers. Therefore, in our search for altematives to the traditional slash-and-bum land preparation (in the context of the SHIFT project "Secondary forests and fallow vegetation in the agricultural landscape ofthe Eastern Amazon region") we opted for field experiments carried out on small-farmers' land in an old agricultural landscape of the Amazon region. To achieve our objective we follow a phased plan: (i) exploratory research (ii) technology development and prototype evaluation and (iii) adoption-oriented research. During the exploratory project phase we identified the critical needs for improvement, focusing on nutrient dynamics, fallow regeneration, and the replacement of buming during land preparation. Then, instead of designing a completely new land-use system, we aimed at modifying those components of the traditional system which cause degradation processes due to intensified land use or introducing new components which have the potential to prevent these. Alternative technologies were developed as a set of modules including the development of a tractor-driven bush chopper for fire-free land clearing and mulching, enrichment planting with fast-growing leguminous trees to improve the biomass production of the fallow vegetation, shifts in the cropping sequence as well as the screening of modem low-input crop varieties under mulch conditions. Adoption of these modules is flexible, leaving the farmer in control of the innovation processo The adoption-oriented research phase is currently underway and assesses the willingness of the farmers to adopt the farming system improvements. Participatory on-farm research facilitates the adoption process
Towards a Generalized Distribution Formalism for Gauge Quantum Fields
We prove that the distributions defined on the Gelfand-Shilov spaces, and
hence more singular than hyperfunctions, retain the angular localizability
property. Specifically, they have uniquely determined support cones. This
result enables one to develop a distribution-theoretic techniques suitable for
the consistent treatment of quantum fields with arbitrarily singular
ultraviolet and infrared behavior. The proofs covering the most general case
are based on the use of the theory of plurisubharmonic functions and
Hormander's estimates.Comment: 12 p., Department of Theoretical Physics, P.N.Lebedev Physical
Institute, Leninsky prosp. 53, Moscow 117924, Russi
Influence of the Dufour effect on convection in binary gas mixtures
Linear and nonlinear properties of convection in binary fluid layers heated
from below are investigated, in particular for gas parameters. A Galerkin
approximation for realistic boundary conditions that describes stationary and
oscillatory convection in the form of straight parallel rolls is used to
determine the influence of the Dufour effect on the bifurcation behaviour of
convective flow intensity, vertical heat current, and concentration mixing. The
Dufour--induced changes in the bifurcation topology and the existence regimes
of stationary and traveling wave convection are elucidated. To check the
validity of the Galerkin results we compare with finite--difference numerical
simulations of the full hydrodynamical field equations. Furthermore, we report
on the scaling behaviour of linear properties of the stationary instability.Comment: 14 pages and 10 figures as uuencoded Postscript file (using uufiles
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