Search results

Filter

Filetype

Your search for "*" yielded 531998 hits

Anti-Stokes resonant x-ray Raman scattering for atom specific and excited state selective dynamics

Ultrafast electronic and structural dynamics of matter govern rate and selectivity of chemical reactions, as well as phase transitions and efficient switching in functional materials. Since x-rays determine electronic and structural properties with elemental, chemical, orbital and magnetic selectivity, short pulse x-ray sources have become central enablers of ultrafast science. Despite of these st

Commuting, Health, and Wellbeing : Mode and duration matters

Allt fler personer reser allt längre sträckor för att ta sig till och från jobbet. En starkt bidragande orsak till detta är en strävan att öka den ekonomiska tillväxten genom att göra arbetskraften tillgänglig över allt större geografiska områden. I Sverige har både pendlingstid och avstånd stadigt ökat under de senaste decennierna och idag tillbringar den genomsnittliga pendlaren mer än en timme Allt fler personer reser allt längre sträckor för att ta sig till och från jobbet. En starkt bidragande orsak till detta är en strävan att öka den ekonomiska tillväxten genom att göra arbetskraften tillgänglig över allt större geografiska områden. I Sverige har både pendlingstid och avstånd stadigt ökat under de senaste decennierna och idag tillbringar den genomsnittliga pendlaren mer än en timme

Anticipated guilt for not helping and anticipated warm glow for helping are differently impacted by personal responsibility to help

One important motivation for people behaving prosocially is that they want to avoid negative and obtain positive emotions. In the prosocial behavior literature however, the motivations to avoid negative emotions (e.g., guilt) and to approach positive emotions (e.g., warm glow) are rarely separated, and sometimes even aggregated into a single mood-management construct. The aim of this study was to

On sum rules for scattering in circular polarization

Classical sum rules, that connect the dynamic scattering properties at all frequencies to the static polarizability, can be shown to break down when applied to circular polarization. This has previously been explained in terms of a breach of symmetry with respect to positive and negative frequencies. In this paper, we show an alternative explanation where circular polarization is introduced by usi

Utan karisma: att kunna nå fram till studenterna

Att ha motiverande och engagerande föreläsningar är värdefulla för studenterna. Men inte alla lärare är försedd med en stark och karismatisk personlighet. Detta papper visar möjligheten att använda metoder som undervisas i skådespelarkonstutbildning som ett sätt att kunna nå fram till ens egna åskådare – studenterna – utan karisma. I teaterutbildning förlitar man inte sig på talang eller karisma u

Yes, it is all about fetishism: A response to Daniel Cunha

Daniel Cunha misreads us as suggesting that climate change has been a conscious and deliberate strategy of a global elite. This was very clearly not our suggestion. He proposes that the Marxian concept of fetishism is applicable to anthropogenic climate change, apparently unaware of our recurrent use of precisely this concept in a number of publications over the past decades. We thus fundamentally

On the issue of simulating very large endfire arrays with complex antenna geometries

This paper discusses some of the main issues of efficient analysis of electrically very large endfire arrays, and further proposes approaches for developing flexible simulation tools for this particular purpose. Some initial results supporting the endfire array design issue are presented, as well as some preliminary examples of implemented compression- and acceleration methods.

State-space models for stored energy and Q-factors

Q-factors are often used to quantify bandwidth performance of resonant structures. The Q-factor is defined as the quotient between the stored and dissipated energies. The time average dissipated energy is reformulated in the dissipated power and is well defined. The definition and evaluation of the stored energy is much more challenging and there are presently several proposals but none is applica

Physical bounds and automatic design of antennas above ground planes

Physical bounds for antennas above ground planes are calculated by optimizing the antenna current. The bounds are compared with antennas modeled as fragmented patches and optimized using genetic algorithms. Monopole structures over ground planes are modeled with image theory and optimized. The monopole over ground plane structure simplifies experimental verification of the bounds.

T-matrix simulations of a collection of scatterers for validation of numerical electromagnetic solvers

This paper presents the use of the T-matrix method for a collection of scatterers for validation purposes of large-scale numerical electromagnetic scattering problems. In order to validate the simulation results for large geometries the T-matrix solution for a collection of spheres and disks can be used. Scattering results using the T-matrix method, FDTD and MoM are compared. The results show that

On multi-dimensional systems; Properties of their transfer functions

A range of interesting electromagnetic systems like antennas, extraordinary transmission and absorbers have been shown to have certain bandwidth limitations given by a family of sum-rules. Common for the systems are that they are passive, linear and time-translational invariant. In this paper we shortly review the extension from one-dimensional passive systems to multi-dimensional systems, aiming

Prominent role of oxygen in the multiferroicity of DyMnO3 and TbMnO3: A resonant soft x-ray scattering spectroscopy study

Oxygen is known to play an important role in the multiferroicity of rare earth manganites; however, how this role changes with rare earth elements is still not fully understood. To address this question, we have used resonant soft x-ray scattering spectroscopy to study the F-type (0,τ,0) diffraction peak from the antiferromagnetic order in DyMnO3 and TbMnO3. We focus on the measurements at O K edg

Silicon diode as an alpha particle detector and spectrometer for direct field measurements

A windowless silicon (Si) diode (4 mm2) was evaluated as alpha particle detector and spectrometer for field measurements. It was irradiated with alpha particles from a 241Am (2.3 kBq) and a 210Po (9 kBq) source at source-detector distances (SDD) of 0.5, 1.0 and 1.8 cm. The energy resolution in terms of full width at half maximum was 281, 148 and 113 keV for SDD of 0.5, 1.0 and 1.8 cm, respectively

Assessment framework for a methodology under development – Application to the PDA methodology

This paper presents an assessment framework for methodologies under development. It is adapted from the evaluation framework for the design of an engineering model developed by Ben Ahmed and colleagues [1]. The assessment framework allows to take into account in a systematic way characteristics (that is, main categories or classes of potential requirements) that are of importance for the assessmen

Late cardiac events after childhood cancer : Methodological aspects of the pan-european study pancaresurfup

Background and Aim Childhood cancer survivors are at high risk of long-term adverse effects of cancer and its treatment, including cardiac events. The pan-European PanCareSurFup study determined the incidence and risk factors for cardiac events among childhood cancer survivors. The aim of this article is to describe the methodology of the cardiac cohort and nested case-control study within PanCare

An appropriate inspiratory flow pattern can enhance CO2 exchange, facilitating protective ventilation of healthy lungs

Background In acute lung injury, CO2 exchange is enhanced by prolonging the volume-weighted mean time for fresh gas to mix with resident alveolar gas, denoted mean distribution time (MDT), and by increasing the flow rate immediately before inspiratory flow interruption, end-inspiratory flow (EIF). The objective was to study these effects in human subjects without lung disease and to analyse the re

Commenting, Sharing and Tweeting News : Measuring Online News Participation

Social plugins for sharing news through Facebook and Twitter have become increasingly salient features on news sites. Together with the user comment feature, social plugins are the most common way for users to contribute. The wide use of multiple features has opened new areas to comprehensively study users’ participatory practices. However, how do these opportunities to participate vary between th

Optimal office lighting use : A Swedish case study

Purpose– The purpose of this paper is to determine the optimal office lighting use with different types of lighting controls to achieve energy savings and provide visual comfort for individuals.Design/methodology/approach– A case study and field measurements were carried out in 18 single-occupancy offices in Sweden where six different lighting controls were investigated. Occupancy and daylight hou

The Road to Rio : Medical and Scientific Perspectives on the 2016 Paralympic Games

In August and September of this year, the world will turn its attention to Rio de Janeiro, Brazil, for the 2016 Summer Olympic and Paralympic Games. Of interest to physiatrists, the Paralympic Games will take place from September 7 to 18, with an estimated total of 4 billion viewers. In the United States, for the first time in history, the Summer Games will be broadcast over a total of 66 hours on