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Helliwell J.F.,University of British Columbia | Helliwell J.F.,Canadian Institute for Advanced Research CIFAR | Wang S.,Korea Development Institute KDI
PLoS ONE | Year: 2015

In this paper we estimate the size of weekend effects for seven emotions and then explore their main determinants for the working population in the United States, using the Gallup/ Healthways US Daily Poll 2008-2012. We first find that weekend effects exist for all emotions, and that these effects are not explained by sample selection bias. Full-time workers have larger weekend effects than do part-time workers. We then explore the sources of weekend effects and find that workplace trust and workplace social relations, combined with differences in social time spent with family and friends, together almost fully explain the weekend effects for happiness, laughter, enjoyment and sadness, for both full-time and part-time workers, with significant but smaller proportions explained for the remaining three emotions-worry, anger and stress. Finally, we show that workplace trust and social relations significantly improve emotions and life evaluations on both weekends and weekdays for all workers. ©2015 Helliwell, Wang.This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Gunther A.A.,TU Dresden | Sawatzki M.,TU Dresden | Formanek P.,Leibniz Institute of Polymer Research | Kasemann D.,CreaPhys GmbH | And 2 more authors.
Advanced Functional Materials | Year: 2016

Doping is a powerful tool to overcome contact limitations in short-channel organic field-effect transistors (OFETs) and has been successfully used in the past to improve the charge carrier injection in OFETs. The present study applies this familiar concept to the architecture of vertical organic field-effect transistors (VOFETs), which are often severely limited by injection due to their very short channel lengths. The present study shows that the performance of p-type VOFETs with pentacene as an active material can be significantly enhanced by the addition of the common p-dopant C60F36 as a thin injection layer underneath the VOFET source electrode, resulting in an increase of On-state current and On/Off ratio by one order of magnitude. The present study further investigates mixed injection layers of pentacene and the p-dopant and finds that the improvement is less pronounced than for the pure dopant layers and depends on the concentration of dopant molecules in the injection layer. Through application of the transfer length method to equivalent OFET geometries, the present study is finally able to link the observed improvement to a decrease in transfer length and can thus conclude that this length is a crucial parameter onto which further improvement efforts have to be concentrated to realize true short-channel VOFETs. © 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Palenzuela C.,Canadian Institute for Theoretical Astrophysics | Palenzuela C.,Louisiana State University | Garrett T.,Louisiana State University | Garrett T.,Perimeter Institute for Theoretical Physics | And 4 more authors.
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2010

The interaction of black holes with ambient magnetic fields is important for a variety of highly energetic astrophysical phenomena. We study this interaction within the force-free approximation in which a tenuous plasma is assumed to have zero inertia. Blandford and Znajek used this approach to demonstrate the conversion of some of the black hole's energy into electromagnetic Poynting flux in stationary and axisymmetric single black hole systems. We adopt this approach and extend it to examine asymmetric and, most importantly, dynamical systems by implementing the fully nonlinear field equations of general relativity coupled to Maxwell's equations. For single black holes, we study, in particular, the dependence of the Poynting flux and show that, even for misalignments between the black hole spin and the direction of the asymptotic magnetic field, a Poynting flux is generated with a luminosity dependent on such misalignment. For binary black hole systems, we show both in the head-on and orbiting cases that the moving black holes generate a Poynting flux. © 2010 The American Physical Society.

Palenzuela C.,Canadian Institute for Theoretical Astrophysics CITA | Palenzuela C.,Max Planck Institute For Gravitationsphysik | Lehner L.,Perimeter Institute for Theoretical Physics | Lehner L.,University of Guelph | And 2 more authors.
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2010

In addition to producing loud gravitational waves, the dynamics of a binary black hole system could induce emission of electromagnetic radiation by affecting the behavior of plasmas and electromagnetic fields in their vicinity. We study how the electromagnetic fields are affected by a pair of orbiting black holes through the merger. In particular, we show how the binary's dynamics induce a variability in possible electromagnetically induced emissions as well as an enhancement of electromagnetic fields during the late-merge and merger epochs. These time dependent features will likely leave their imprint in processes generating detectable emissions and can be exploited in the detection of electromagnetic counterparts of gravitational waves. © 2010 The American Physical Society.

Lehner L.,Perimeter Institute for Theoretical Physics | Lehner L.,University of Guelph | Lehner L.,Canadian Institute for Advanced Research CIFAR | Pretorius F.,Princeton University
Physical Review Letters | Year: 2010

We describe the behavior of 5-dimensional black strings, subject to the Gregory-Laflamme instability. Beyond the linear level, the evolving strings exhibit a rich dynamics, where at intermediate stages the horizon can be described as a sequence of 3-dimensional spherical black holes joined by black string segments. These segments are themselves subject to a Gregory-Laflamme instability, resulting in a self-similar cascade, where ever-smaller satellite black holes form connected by ever-thinner string segments. This behavior is akin to satellite formation in low-viscosity fluid streams subject to the Rayleigh-Plateau instability. The simulation results imply that the string segments will reach zero radius in finite asymptotic time, whence the classical space-time terminates in a naked singularity. Since no fine-tuning is required to excite the instability, this constitutes a generic violation of cosmic censorship.

Yoneda J.,University of Tokyo | Yoneda J.,RIKEN | Otsuka T.,University of Tokyo | Otsuka T.,RIKEN | And 11 more authors.
Physical Review Letters | Year: 2014

We demonstrate fast universal electrical spin manipulation with inhomogeneous magnetic fields. With fast Rabi frequency up to 127 MHz, we leave the conventional regime of strong nuclear-spin influence and observe a spin-flip fidelity >96%, a distinct chevron Rabi pattern in the spectral-time domain, and a spin resonance linewidth limited by the Rabi frequency, not by the dephasing rate. In addition, we establish fast z rotations up to 54 MHz by directly controlling the spin phase. Our findings will significantly facilitate tomography and error correction with electron spins in quantum dots. © 2014 American Physical Society.

Sullivan A.M.,University of Washington | Arsovski A.A.,University of Washington | Lempe J.,University of Washington | Bubb K.L.,University of Washington | And 22 more authors.
Cell Reports | Year: 2014

Our understanding of gene regulation in plants is constrained by our limited knowledge of plant cis-regulatory DNA and its dynamics. We mapped DNase I hypersensitive sites (DHSs) in A. thaliana seedlings and used genomic footprinting to delineate ~700,000 sites of invivo transcription factor (TF) occupancy at nucleotide resolution. We show that variation associated with 72 diverse quantitative phenotypes localizes within DHSs. TF footprints encode an extensive cis-regulatory lexicon subject to recent evolutionary pressures, and widespread TF binding within exons may have shaped codon usage patterns. The architecture of A. thaliana TF regulatory networks is strikingly similar to that ofanimals in spite of diverged regulatory repertoires. We analyzed regulatory landscape dynamics during heat shock and photomorphogenesis, disclosing thousands of environmentally sensitive elements and enabling mapping of key TF regulatory circuits underlying these fundamental responses. Our results provide an extensive resource for the study of A. thaliana gene regulation and functional biology. © 2014 The Authors.

Park Y.,Institute For Angewandte Photophysik | Muller-Meskamp L.,Institute For Angewandte Photophysik | Vandewal K.,Institute For Angewandte Photophysik | Leo K.,Institute For Angewandte Photophysik | Leo K.,Canadian Institute for Advanced Research CIFAR
Applied Physics Letters | Year: 2016

The performance of organic optoelectronic devices can be improved by employing a suitable optical cavity design beyond the standard plane layer approach, e.g., by the inclusion of periodically or randomly textured structures which increase light incoupling or extraction. One of the simplest approaches is to add an additional layer containing light scattering particles into the device stack. Solution processed poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) thin films are promising for replacing the brittle and expensive indium tin oxide transparent electrode. We use a blend of 100 nm TiO2 scattering particles in PEDOT:PSS solution to fabricate transparent electrode films which also functions as a scattering layer. When utilized in an organic photovoltaic device, a power conversion efficiency of 7.92% is achieved, which is an 8.6% relative improvement compared to a device with a neat PEDOT:PSS electrode without the nanoparticles. This improvement is caused by an increase in short-circuit current due to an improved photon harvesting in the 320 nm-700 nm spectral wavelength range. © 2016 Author(s).

Aknin L.B.,Simon Fraser University | Aknin L.B.,Canadian Institute for Advanced Research CIFAR | Broesch T.,Simon Fraser University | Kiley Hamlin J.,Columbia University | Van De Vondervoort J.M.,Columbia University
Journal of Experimental Psychology: General | Year: 2015

Humans are extraordinarily prosocial, and research conducted primarily in North America indicates that giving to others is emotionally rewarding. To examine whether the hedonic benefits of giving represent a universal feature of human behavior, we extended upon previous cross-cultural examinations by investigating whether inhabitants of a small-scale, rural, and isolated village in Vanuatu, where villagers have little influence from urban, Western culture, survive on subsistence farming without electricity, and have minimal formal education, report or display emotional rewards from engaging in prosocial (vs. personally beneficial) behavior. In Study 1, adults were randomly assigned to purchase candy for either themselves or others and then reported their positive affect. Consistent with previous research, adults purchasing goods for others reported greater positive emotion than adults receiving resources for themselves. In Study 2, 2- to 5-year-old children received candy and were subsequently asked to engage in costly giving (sharing their own candy with a puppet) and non-costly giving (sharing the experimenter's candy with a puppet). Emotional expressions were video-recorded during the experiment and later coded for happiness. Consistent with previous research conducted in Canada, children displayed more happiness when giving treats away than when receiving treats themselves. Moreover, the emotional rewards of giving were largest when children engaged in costly (vs. non-costly) giving. Taken together, these findings indicate that the emotional rewards of giving are detectable in people living in diverse societies and support the possibility that the hedonic benefits of generosity are universal. © 2015 American Psychological Association.

Harvey-Collard P.,Université de Sherbrooke | Drouin D.,Université de Sherbrooke | Pioro-Ladriere M.,Université de Sherbrooke | Pioro-Ladriere M.,Canadian Institute for Advanced Research CIFAR
Applied Physics Letters | Year: 2014

In this work, we demonstrate a silicon nanocrystal Field Effect Transistor (ncFET). Its operation is similar to that of a Tunnelling Field Effect Transistor (TFET) with two barriers in series. The tunnelling barriers are fabricated in very thin silicon dioxide and the channel in intrinsic polycrystalline silicon. The absence of doping eliminates the problem of achieving sharp doping profiles at the junctions, which has proven a challenge for large-scale integration and, in principle, allows scaling down the atomic level. The demonstrated ncFET features a 104 on/off current ratio at room temperature, a low 30 pA/μm leakage current at a 0.5 V bias, an on-state current on a par with typical all-Si TFETs and bipolar operation with high symmetry. Quantum dot transport spectroscopy is used to assess the band structure and energy levels of the silicon island. © 2014 AIP Publishing LLC.

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