Near collapse of the meridional SST gradient in the eastern equatorial Pacific during Heinrich Stadial 1

Author Posting. © American Geophysical Union, 2013. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography 28 (2013): 663–674, doi:10.1002/2013PA002499.Sea surface temperatures (SST) and inorganic continental input over the last 25,000 years (25 ka) are reconstructed in the far eastern equatorial Pacific (EEP) based on three cores stretching from the equatorial front (~0.01°N, ME0005-24JC) into the cold tongue region (~3.6°S; TR163-31P and V19-30). We revisit previously published alkenone-derived SST records for these sites and present a revised chronology for V19-30. Inorganic continental input is quantified at all three sites based on 230Th-normalized fluxes of the long-lived continental isotope thorium-232 and interpreted to be largely dust. Our data show a very weak meridional (cross-equatorial) SST gradient during Heinrich Stadial 1 (HS1, 18–15 ka B.P.) and high dust input along with peak export production at and north of the equator. These findings are corroborated by an Earth system model experiment for HS1 that simulates intensified northeasterly trade winds in the EEP, stronger equatorial upwelling, and surface cooling. Furthermore, the related southward shift of the Intertropical Convergence Zone (ITCZ) during HS1 is also indicative of drier conditions in the typical source regions for dust.This work was supported by grants from the Canadian Foundation for Climate and Atmospheric Sciences (CFCAS), the Canadian Institute for Advanced Research (CIFAR), the Natural Sciences and Engineering Research Council (NSERC), Canada and the National Science Foundation (NSF), USA. A. Timmermann and T. Friedrich were supported by NSF grant 1010869.2014-05-2

Policies for an Ageing Workforce Work-life balance, working conditions and equal opportunities 2019

At a time of rapid population ageing, a key means of sustaining current welfare states is to extend the length of working lives. In 2050, the share of people over the age of 75 years will be the same as the share over 65 years today. And just as not all are able to work to the age of 65 now, not everyone will be able to work to the age of 75 in 2050; even if future older workers will in all likelihood be healthier and have better working aids at their disposal. Extending average working lives by 10 years, and at the same time ensuring an adequate social safety net for those unable to work into their late 60s and 70s, is a major social policy challenge for the coming decades. And because people are much more likely to work late in life if they had stable careers before reaching 60, tackling this policy challenge means pulling on many more social policy levers than just pension policy. While being keenly aware of these issues and how they relate to the overall agenda of active ageing, Commissioner Thyssen also reminds us in her Foreword that marked increases in life expectancy – both past and in the future – represent enormous social progress. The Commissioner makes the point that older people too contribute to society. And more so with lifelong learning and investment in skills

Efficient Magnus-type integrators for solar energy conversion in Hubbard models

Strongly interacting electrons in solids are generically described by Hubbardtype models, and the impact of solar light can be modeled by an additional time-dependence. This yields a finite dimensional system of ordinary differential equations (ODE)s of Schr\"odinger type, which can be solved numerically by exponential time integrators of Magnus type. The efficiency may be enhanced by combining these with operator splittings. We will discuss several different approaches of employing exponential-based methods in conjunction with an adaptive Lanczos method for the evaluation of matrix exponentials and compare their accuracy and efficiency. For each integrator, we use defect-based local error estimators to enable adaptive time-stepping. This serves to reliably control the approximation error and reduce the computational effor

Recursive Definitions of Monadic Functions

Using standard domain-theoretic fixed-points, we present an approach for defining recursive functions that are formulated in monadic style. The method works both in the simple option monad and the state-exception monad of Isabelle/HOL's imperative programming extension, which results in a convenient definition principle for imperative programs, which were previously hard to define. For such monadic functions, the recursion equation can always be derived without preconditions, even if the function is partial. The construction is easy to automate, and convenient induction principles can be derived automatically.Comment: In Proceedings PAR 2010, arXiv:1012.455

Test Quality Analysis and Improvement for an Embedded Asynchronous FIFO

Embedded First-InFirst-Out (FIFO) memories are increasingly used in many IC designs.We have created a new full-custom embedded FIFO module withasynchronous read and write clocks, which is at least a factor twosmaller and also faster than SRAM-based and standard-cell-basedcounterparts. The detection qualities of the FIFO test for bothhard and weak resistive shorts and opens have been analyzed by anIFA-like method based on analog simulation. The defect coverage ofthe initial FIFO test for shorts in the bit-cell matrix has beenimproved by inclusion of an additional data background andlow-voltage testing; for low-resistant shorts, 100% defect coverageis obtained. The defect coverage for opens has been improved by anew test procedure which includes waitingperiods

Quantum Noether Method

We present a general method for constructing consistent quantum field theories with global symmetries. We start from a free non-interacting quantum field theory with given global symmetries and we determine all consistent perturbative quantum deformations assuming the construction is not obstructed by anomalies. The method is established within the causal Bogoliubov-Shirkov-Epstein-Glaser approach to perturbative quantum field theory (which leads directly to a finite perturbative series and does not rely on an intermediary regularization). Our construction can be regarded as a direct implementation of Noether's method at the quantum level. We illustrate the method by constructing the pure Yang-Mills theory (where the relevant global symmetry is BRST symmetry), and the N=1 supersymmetric model of Wess and Zumino. The whole construction is done before the so-called adiabatic limit is taken. Thus, all considerations regarding symmetry, unitarity and anomalies are well-defined even for massless theories.Comment: 53 pages, latex, version to appear in Nuclear Physics

Practical Algebraic Renormalization

A practical approach is presented which allows the use of a non-invariant regularization scheme for the computation of quantum corrections in perturbative quantum field theory. The theoretical control of algebraic renormalization over non-invariant counterterms is translated into a practical computational method. We provide a detailed introduction into the handling of the Slavnov-Taylor and Ward-Takahashi identities in the Standard Model both in the conventional and the background gauge. Explicit examples for their practical derivation are presented. After a brief introduction into the Quantum Action Principle the conventional algebraic method which allows for the restoration of the functional identities is discussed. The main point of our approach is the optimization of this procedure which results in an enormous reduction of the calculational effort. The counterterms which have to be computed are universal in the sense that they are independent of the regularization scheme. The method is explicitly illustrated for two processes of phenomenological interest: QCD corrections to the decay of the Higgs boson into two photons and two-loop electroweak corrections to the process $B \to X_s \gamma$.Comment: version to be published in Annals of Physic

Gravity-driven Lyman-alpha blobs from cold streams into galaxies

We use high-resolution cosmological hydrodynamical AMR simulations to predict the characteristics of La emission from the cold gas streams that fed galaxies in massive haloes at high redshift. The La luminosity in our simulations is powered by the release of gravitational energy as gas flows from the intergalactic medium into the halo potential wells. The UV background contributes only <20% to the gas heating. The La emissivity is due primarily to electron-impact excitation cooling radiation in gas ~2x10^4K. We calculate the La emissivities assuming collisional ionisation equilibrium (CIE) at all gas temperatures. The simulated streams are self-shielded against the UV background, so photoionisation and recombination contribute negligibly to the La line formation. We produce theoretical maps of the La surface brightnesses, assuming that ~85% of the La photons are directly observable. We find that typical haloes of mass Mv~10^12-13 Msun at z~3 emit as La blobs (LABs) with luminosities 10^43-44 erg/s. Most of the La comes from the extended narrow, partly clumpy, inflowing, cold streams that feed the growing galaxies. The predicted LAB morphology is therefore irregular, with dense clumps and elongated extensions. The linewidth is expected to range from 10^2 to more than 10^3 km/s with a large variance. The typical La surface brightness profile is proportional to r^-1.2 where r is the distance from the halo centre. Our simulated LABs are similar in luminosity, morphology and extent to the observed LABs, with distinct kinematic features. The predicted La luminosity function is consistent with observations, and the predicted areas and linewidths roughly recover the observed scaling relations. This mechanism for producing LABs appears inevitable in many high-z galaxies. Some of the LABs may thus be regarded as direct detections of the cold streams that drove galaxy evolution at high z.Comment: 21 pages, 20 figures, final version accepted for publication in MNRA

Fluid Flow Programming in Paper-Derived Silica–Polymer Hybrids

In paper-based devices, capillary fluid flow is based on length-scale selective functional control within a hierarchical porous system. The fluid flow can be tuned by altering the paper preparation process, which controls parameters such as the paper grammage. Interestingly, the fiber morphology and nanoporosity are often neglected. In this work, porous voids are incorporated into paper by the combination of dense or mesoporous ceramic silica coatings with hierarchically porous cotton linter paper. Varying the silica coating leads to significant changes in the fluid flow characteristics, up to the complete water exclusion without any further fiber surface hydrophobization, providing new approaches to control fluid flow. Additionally, functionalization with redox-responsive polymers leads to reversible, dynamic gating of fluid flow in these hybrid paper materials, demonstrating the potential of length scale specific, dynamic, and external transport control

Service triads:a research agenda for buyer–supplier–customer triads in business services

Service triads, in which a buyer contracts with a supplier to deliver services directly to the buyer's customer, represent an emerging business model. This special issue is dedicated to this theme. To set the context, in this lead article, we first define service triads, both as a phenomenon and a research topic. We then provide a review of different strands of existing research and various theoretical frameworks that can inform our study of service triads. This culminates in an outline of a research agenda that can guide future study. As such, this paper not only introduces the articles in the special issue, but is also intended as a point of reference and motivation for further work on service triads, and on triads in general