Overcoming status quo bias in the human brain

Humans often accept the status quo when faced with conflicting choice alternatives. However, it is unknown how neural pathways connecting cognition with action modulate this status quo acceptance. Here we developed a visual detection task in which subjects tended to favor the default when making difficult, but not easy, decisions. This bias was suboptimal in that more errors were made when the default was accepted. A selective increase in subthalamic nucleus (STN) activity was found when the status quo was rejected in the face of heightened decision difficulty. Analysis of effective connectivity showed that inferior frontal cortex, a region more active for difficult decisions, exerted an enhanced modulatory influence on the STN during switches away from the status quo. These data suggest that the neural circuits required to initiate controlled, nondefault actions are similar to those previously shown to mediate outright response suppression. We conclude that specific prefrontal-basal ganglia dynamics are involved in rejecting the default, a mechanism that may be important in a range of difficult choice scenarios

Spectra of weighted algebras of holomorphic functions

We consider weighted algebras of holomorphic functions on a Banach space. We determine conditions on a family of weights that assure that the corresponding weighted space is an algebra or has polynomial Schauder decompositions. We study the spectra of weighted algebras and endow them with an analytic structure. We also deal with composition operators and algebra homomorphisms, in particular to investigate how their induced mappings act on the analytic structure of the spectrum. Moreover, a Banach-Stone type question is addressed.Comment: 25 pages Corrected typo

Evaluation of Vascular Control Mechanisms Utilizing Video Microscopy of Isolated Resistance Arteries of Rats

This protocol describes the use of in vitro television microscopy to evaluate vascular function in isolated cerebral resistance arteries (and other vessels), and describes techniques for evaluating tissue perfusion using Laser Doppler Flowmetry (LDF) and microvessel density utilizing fluorescently labeled Griffonia simplicifolia (GS1) lectin. Current methods for studying isolated resistance arteries at transmural pressures encountered in vivo and in the absence of parenchymal cell influences provide a critical link between in vivo studies and information gained from molecular reductionist approaches that provide limited insight into integrative responses at the whole animal level. LDF and techniques to selectively identify arterioles and capillaries with fluorescently-labeled GS1 lectin provide practical solutions to enable investigators to extend the knowledge gained from studies of isolated resistance arteries. This paper describes the application of these techniques to gain fundamental knowledge of vascular physiology and pathology in the rat as a general experimental model, and in a variety of specialized genetically engineered designer rat strains that can provide important insight into the influence of specific genes on important vascular phenotypes. Utilizing these valuable experimental approaches in rat strains developed by selective breeding strategies and new technologies for producing gene knockout models in the rat, will expand the rigor of scientific premises developed in knockout mouse models and extend that knowledge to a more relevant animal model, with a well understood physiological background and suitability for physiological studies because of its larger size

Superuniversality in phase-ordering disordered ferromagnets

The phase-ordering kinetics of the ferromagnetic two-dimensional Ising model with uniform bond disorder is investigated by intensive Monte Carlo simulations. Simple ageing behaviour is observed in the single-time correlator and the two-time responses and correlators. The dynamical exponent z and the autocorrelation exponent lambda_C only depend on the ratio eps/T, where eps describes the width of the distribution of the disorder, whereas a more complicated behaviour is found for the non-equilibrium exponent a of the two-time response as well as for the autoresponse exponent lambda_R. The scaling functions are observed to depend only on the dimensionless ratio eps/T. If the length scales are measured in terms of the time-dependent domain size L(t), the form of the scaling functions is in general independent of both eps and T. Conditions limiting the validity of this `superuniversality' are discussed.Comment: Latex2e, 10pp with 8 figures included, PR macro

Direct Observation of Dynamic Symmetry Breaking above Room Temperature in Methylammonium Lead Iodide Perovskite

Lead halide perovskites such as methylammonium lead triiodide (MAPI) have outstanding optical and electronic properties for photovoltaic applications, yet a full understanding of how this solution processable material works so well is currently missing. Previous research has revealed that MAPI possesses multiple forms of static disorder regardless of preparation method, which is surprising in light of its excellent performance. Using high energy resolution inelastic X-ray (HERIX) scattering, we measure phonon dispersions in MAPI and find direct evidence for another form of disorder in single crystals: large amplitude anharmonic zone-edge rotational instabilities of the PbI_6 octahedra that persist to room temperature and above, left over from structural phase transitions that take place tens to hundreds of degrees below. Phonon calculations show that the orientations of the methylammonium couple strongly and cooperatively to these modes. The result is a non-centrosymmetric, instantaneous local structure, which we observe in atomic pair distribution function (PDF) measurements. This local symmetry breaking is unobservable by Bragg diffraction, but can explain key material properties such as the structural phase sequence, ultra low thermal transport, and large minority charge carrier lifetimes despite moderate carrier mobility.Comment: 30 pages, 11 figure

Electronic spectroscopy of trans-azomethane by electron impact

The electron impact excitation of trans-azomethane (i.e., trans-dimethyl diazine CH3–N–N–CH3) has been studied by both trapped electron (TE) and differential electron scattering (DES) techniques. The nature of the excited state in each of several transitions has been identified by the energy and angular dependences of the excitation cross section. Two previously unreported singlet-->triplet transitions are observed with maxima at 2.75 and 4.84 eV. Theoretical calculations on the parent compound, trans-diimide (H–N=N–H), suggest that these are the χ 1Ag-->1 3Bg (produced by excitation of an electron from an n + molecular orbital to a pi* molecular orbital) and the χ 1Ag-->1 3Bu (pi-->pi*) transitions, respectively. The χ 1Ag-->1 1Bg (n + -->pi*) transition is observed with a peak at 3.50 eV in the DES studies. A strong peak at 6.01 eV in the TE spectra appears as a weak shoulder in the DES studies and is interpreted as either a symmetry-forbidden or Rydberg-like singlet-->singlet transition. Allowed singlet-->singlet features overlap each other in the transition energy range from 6 to 10 eV. Peaks are seen in the DES spectra at 6.71, 7.8, and 9.5 eV and in the TE spectrum at 8.0 eV. Several significant differences between the TE and the DES spectra are analyzed on the basis of the different nature of the two experiments

Governance of Offshore IT Outsourcing at Shell Global Functions IT-BAM Development and Application of a Governance Framework to Improve Outsourcing Relationships

The lack of effective IT governance is widely recognized as a key inhibitor to successful global IT outsourcing relationships. In this study we present the development and application of a governance framework to improve outsourcing relationships. The approach used to developing an IT governance framework includes a meta model and a customization process to fit the framework to the target organization. The IT governance framework consists of four different elements (1) organisational structures, (2) joint processes between in- and outsourcer, (3) responsibilities that link roles to processes and (4) a diverse set of control indicators to measure the success of the relationship. The IT governance framework is put in practice in Shell GFIT BAM, a part of Shell that concluded to have a lack of management control over at least one of their outsourcing relationships. In a workshop the governance framework was used to perform a gap analysis between the current and desired governance. Several gaps were identified in the way roles and responsibilities are assigned and joint processes are set-up. Moreover, this workshop also showed the usefulness and usability of the IT governance framework in structuring, providing input and managing stakeholders in the discussions around IT governance

A 15 year slow-slip event on the Sunda megathrust offshore Sumatra

In the Banyak Islands of Sumatra, coral microatoll records reveal a 15 year-long reversal of interseismic vertical displacement from subsidence to uplift between 1966 and 1981. To explain these coral observations, we test four hypotheses, including regional sea level changes and various tectonic mechanisms. Our results show that the coral observations likely reflect a 15 year-long slow-slip event (SSE) on the Sunda megathrust. This long-duration SSE exceeds the duration of previously reported SSEs and demonstrates the importance of multidecade geodetic records in illuminating the full spectrum of megathrust slip behavior at subduction zones

Fluctuations of two-time quantities and time-reparametrization invariance in spin-glasses

This article is a contribution to the understanding of fluctuations in the out of equilibrium dynamics of glassy systems. By extending theoretical ideas based on the assumption that time-reparametrization invariance develops asymptotically we deduce the scaling properties of diverse high-order correlation functions. We examine these predictions with numerical tests in a standard glassy model, the 3d Edwards-Anderson spin-glass, and in a system where time-reparametrization invariance is not expected to hold, the 2d ferromagnetic Ising model, both at low temperatures. Our results enlighten a qualitative difference between the fluctuation properties of the two models and show that scaling properties conform to the time-reparametrization invariance scenario in the former but not in the latter.Comment: 17 pages, 5 figure

Optimizing Jastrow factors for the transcorrelated method

We investigate the optimization of flexible tailored real-space Jastrow factors for use in the transcorrelated (TC) method in combination with highly accurate quantum chemistry methods, such as initiator full configuration interaction quantum Monte Carlo (FCIQMC). Jastrow factors obtained by minimizing the variance of the TC reference energy are found to yield better, more consistent results than those obtained by minimizing the variational energy. We compute all-electron atomization energies for the challenging first-row molecules C2, CN, N2, and O2 and find that the TC method yields chemically accurate results using only the cc-pVTZ basis set, roughly matching the accuracy of non-TC calculations with the much larger cc-pV5Z basis set. We also investigate an approximation in which pure three-body excitations are neglected from the TC-FCIQMC dynamics, saving storage and computational costs, and show that it affects relative energies negligibly. Our results demonstrate that the combination of tailored real-space Jastrow factors with the multi-configurational TC-FCIQMC method provides a route to obtaining chemical accuracy using modest basis sets, obviating the need for basis-set extrapolation and composite techniques