Nonperturbative resonant strong field ionization of atomic hydrogen

We investigate resonant strong field ionization of atomic hydrogen with respect to the 1s-2p-transition. By "strong" we understand that Rabi-periods are executed on a femtosecond time scale. Ionization and AC Stark shifts modify the bound state dynamics severely, leading to nonperturbative signatures in the photoelectron spectra. We introduce an analytical model, capable of predicting qualitative features in the photoelectron spectra such as the positions of the Autler-Townes peaks for modest field strengths. Ab initio solutions of the time-dependent Schroedinger equation show a pronounced shift and broadening of the left Autler-Townes peak as the field strength is increased. The right peak remains rather narrow and shifts less. This result is analyzed and explained with the help of exact AC Stark shifts and ionization rates obtained from Floquet theory. Finally, it is demonstrated that in the case of finite pulses as short as 20fs the Autler-Townes duplet can still be resolved. The fourth generation light sources under construction worldwide will provide bright, coherent radiation with photon energies ranging from a tenth of a meV up to tens of keV, hence covering the regime studied in the paper so that measurements of nonperturbative, relative AC Stark shifts should become feasible with these new light sources.Comment: 16 pages, 11 figures, IOP styl

A low noise, high thermal stability, 0.1 K test facility for the Planck HFI bolometers

We are developing a facility which will be used to characterize the bolometric detectors for Planck, an ESA mission to investigate the Cosmic Microwave Background. The bolometers operate at 0.1 K, employing neutron-transmutation doped (NTD) Ge thermistors with resistances of several megohms to achieve NEPs~1×10^(–17) W Hz^(–1/2). Characterization of the intrinsic noise of the bolometers at frequencies as low as 0.010 Hz dictates a test apparatus thermal stability of 40 nK Hz^(–1/2) to that frequency. This temperature stability is achieved via a multi-stage isolation and control geometry with high resolution thermometry implemented with NTD Ge thermistors, JFET source followers, and dedicated lock-in amplifiers. The test facility accommodates 24 channels of differential signal readout, for measurement of bolometer V(I) characteristics and intrinsic noise. The test facility also provides for modulated radiation in the submillimeter band incident on the bolometers, for measurement of the optical speed-of-response; this illumination can be reduced below detectable limits without interrupting cryogenic operation. A commercial Oxford Instruments dilution refrigerator provides the cryogenic environment for the test facility

Nonlinear Terms of MHD Equations for Homogeneous Magnetized Shear Flow

We have derived the full set of MHD equations for incompressible shear flow of a magnetized fluid and considered their solution in the wave-vector space. The linearized equations give the famous amplification of slow magnetosonic waves and describe the magnetorotational instability. The nonlinear terms in our analysis are responsible for the creation of turbulence and self-sustained spectral density of the MHD (Alfven and pseudo-Alfven) waves. Perspectives for numerical simulations of weak turbulence and calculation of the effective viscosity of accretion disks are shortly discussed in k-space.Comment: 13 pages, no figures; AIP Conference Proceedings 1356, Proceedings of the School and Workshop on Space Plasma Physics (1--12 September 2010, Kiten, Bulgaria), American Institute of Physics, Melville, NY, 201

On BPS bounds in D=4 N=2 gauged supergravity II: general matter couplings and black hole masses

We continue the analysis of BPS bounds started in arXiv:1110.2688, extending it to the full class of N=2 gauged supergravity theories with arbitrary vector and hypermultiplets. We derive the general form of the asymptotic charges for asymptotically flat (M_4), anti-de Sitter (AdS_4), and magnetic anti-de Sitter (mAdS_4) spacetimes. Some particular examples from black hole physics are given to explicitly demonstrate how AdS and mAdS masses differ when solutions with non-trivial scalar profiles are considered.Comment: 21 pages; v2 added reference, published version; v3 minor correction

DIAGNOSTICAL VALUE OF LIQUOR CHANGES IN BRAIN STROKE PATIENTS

No abstrac

Lossless Transmission Lines Terminated by Linear and Nonlinear RLC-Loads

Here we consider lossless transmission lines terminated by a circuit consisting of linear and nonlinear RGCL-loads. First we overcome a difficulty caused by nonlinear boundary conditions utilizing Kirchhoff’s laws. The problem arising is to choose as many equations as are the unknown functions. Then we formulate the mixed problem for the hyperbolic system, reduce the mixed problem to an initial value problem on the boundary and obtain a neutral system with respect to new variables. Further on we prove an existence-uniqueness theorem for periodic solution in lossless case

Does distributed leadership have a place in destination management organisations? A policy-makers perspective

Within an increasingly networked environment and recent transitions in the landscape of funding for destination management organisations (DMOs) and destinations, pooling knowledge and resources may well be seen as a prerequisite to ensuring the long-term sustainability of reshaped, yet financially constrained DMOs facing severe challenges to deliver value to destinations, visitors and member organisations. Distributed Leadership (DL) is a recent paradigm gaining momentum in destination research as a promising response to these challenges. Building on the scarce literature on DL in a DMO context, this paper provides a policy-makers’ perspective into the place of DL in reshaped DMOs and DMOs undergoing transformation and explores current challenges and opportunities to the enactment and practice of DL. The underpinned investigation used in-depth, semi-structured interviews with policy-makers from VisitEngland following an interview agenda based on the DMO Leadership Cycle. Policy-makers within VisitEngland saw a multitude of opportunities for DMOs with regards to DL, but equally, they emphasised challenges acting as barriers to realising the potential benefits of introducing a DL model to DMOs as a response to uncertainty in the funding landscape

Data Parallel Hypersweeps for in Situ Topological Analysis

The contour tree is a tool for understanding the topological structure of a scalar field. Recent work has built efficient contour tree algorithms for shared memory parallel computation, driven by the need to analyze large data sets in situ while the simulation is running. Unfortunately, methods for using the contour tree for practical data analysis are still primarily serial, including single isocontour extraction, branch decomposition and simplification. We report data parallel methods for these tasks using a data structure called the hyperstructure and a general purpose approach called a hypersweep. We implement and integrate these methods with a Cinema database that stores features as depth images and with a web server that reconstructs the features for direct visualization

Rotating BPS black holes in matter-coupled AdS(4) supergravity

Using the general recipe given in arXiv:0804.0009, where all timelike supersymmetric solutions of N=2, D=4 gauged supergravity coupled to abelian vector multiplets were classified, we construct genuine rotating supersymmetric black holes in AdS(4) with nonconstant scalar fields. This is done for the SU(1,1)/U(1) model with prepotential F=-iX^0X^1. In the static case, the black holes are uplifted to eleven dimensions, and generalize the solution found in hep-th/0105250 corresponding to membranes wrapping holomorphic curves in a Calabi-Yau five-fold. The constructed rotating black holes preserve one quarter of the supersymmetry, whereas their near-horizon geometry is one half BPS. Moreover, for constant scalars, we generalize (a supersymmetric subclass of) the Plebanski-Demianski solution of cosmological Einstein-Maxwell theory to an arbitrary number of vector multiplets. Remarkably, the latter turns out to be related to the dimensionally reduced gravitational Chern-Simons action.Comment: 23 pages, uses JHEP3.cl

Consumers’ Preferences towards Bread Characteristics Based on Food-Related Lifestyles: Insights from Slovenia

Consumers’ recognition and understanding of food characteristics can have an important role when making purchase decisions. The current study analysed consumer preferences for bread, an important food in the diets of Central European countries. The study included a conjoint experiment on a representative sample of 547 adult consumers in Slovenia. The following bread attributes: functional ingredients (chia seeds, linseed, quinoa, and Tartary buckwheat); nutritional claims (low salt, high fibre, and high protein); and other claims (organic, free from additives, flour from Slovenia, and wholegrain) were studied. The results showed the strongest relative importance for functional ingredients (a mean relative importance of 83.9%). In addition, a deeper insight into consumer preference was investigated by a recently developed modular instrument for food-related lifestyles. Latent class cluster analysis (LCA) enabled the identification of four consumer segments (uninvolved, conservative, health-conscious, and moderate) with different preferences toward selected functional ingredients, nutrition, and other claims. The results provide insights that allow for a better understanding of consumer preferences for functional ingredients and claims, and new perspectives for bread marketing to different consumer segments based on food-related lifestyles. Identifying the drivers that affect bread purchasing and consumption can support reformulation activities and product promotion in the direction of reinforcing healthier food choices.© 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative CommonsAttribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).fi=vertaisarvioitu|en=peerReviewed