Sökresultat

Filtyp

Din sökning på "*" gav 527946 sökträffar

The allyl radical revisited: A theoretical study of the electronic spectrum.

In this Letter, we report the electronic spectrum of the allyl radical, obtained with multiconfigurational perturbation theory (MS-CASPT2). The assignment of the spectrum is in accordance with experiment to within 0.2 eV. We have computed the complete first Rydberg series and the beginning of the second Rydberg series. A new valence-excited 2B1 state has been found which has hitherto been hidden b

Functional analysis of the classical, alternative, and MBL pathways of the complement system: standardization and validation of a simple ELISA

Primary defence against invading microorganisms depends on a functional innate immune system and the complement system plays a major role in such immunity. Deficiencies in one of the components of the complement system can cause severe and recurrent infections, systemic diseases, such as systemic lupus erythematosus (SLE) and renal disease. Screening for complement deficiencies in the classical or

Multiple Windows for Estimation of Locally Stationary Transients in the Electroencephalogram

In this paper, multiple windows, optimal for locally stationary processes (MW-LSP) are used to estimate the spectrogram of the electroencephalogram (EEG) where we focus on the ability to estimate transient frequency changes. A peak of known frequency was evoked in the EEG spectrum in a predetermined time interval, by using a 9 Hz flickering light. We investigate the multiple windows corresponding

Bose-Einstein correlations in W+W- events at LEP2

Bose-Einstein correlations (BEC) between final state particles in the reaction e(+)e(-) -> W+ W- -> q(1)(q(2)) over barq(3)(q(4)over bar>) over bar) have been studied. Data corresponding to a total integrated luminosity of 550 pb(-1), recorded by the DELPHI detector at centre-of-mass energies ranging from 189 to 209 GeV, were analysed. An indication for inter-W BEC between like-sign particles has

Surface oxides on close-packed surfaces of late transition metals

In recent years, the formation of thin, well-ordered but complex surface oxides on late transition metals has been discovered. The driving force for this line of research has been the strong incentive to increase the partial pressure of oxygen from ultra-high vacuum to conditions more relevant for heterogeneous catalysis. Here we review the present status of the research field. Compared to oxygen

The logarithmic norm. History and modern theory

In his 1958 thesis Stability and Error Bounds, Germund Dahlquist introduced the logarithmic norm in order to derive error bounds in initial value problems, using differential inequalities that distinguished between forward and reverse time integration. Originally defined for matrices, the logarithmic norm can be extended to bounded linear operators, but the extensions to nonlinear maps and unbound

Constructive Methods for SAGBI and SAGBI-Gröbner Bases

Popular Abstract in Swedish Avhandlingen består av en introduktion och följande artiklar: Artikel I: Using resultants for SAGBI basis verification in the univariate polynomial ring. Författare: Anna Torstensson, Victor Ufnarovski och Hans Öfverbeck. Sammanfattning: En resultant-identitet för polynom i en variabel bevisas och används för att karakterisera SAGBI-baser för underalgebror genereradeThe thesis consists of an introduction and the following four papers: Paper I: Using resultants for SAGBI basis verification in the univariate polynomial ring. Authors: Anna Torstensson, Victor Ufnarovski and Hans Öfverbeck. Abstract: A resultant-type identity for univariate polynomials is proved and used to characterise SAGBI bases of subalgebras generated by two polynomials. A new equivalent

Cooling inhibits exocytosis in single mouse pancreatic B-cells by suppression of granule mobilization

1. The mechanisms by which cooling inhibits insulin secretion were investigated by capacitance measurements of exocytosis in single mouse pancreatic B-cells maintained in short-term tissue culture. 2. A reduction of the bath temperature from 34 to 24 degrees C produced a gradual inhibition of exocytosis. Inhibition of exocytosis was use dependent rather than time dependent. The steady-state inhibi

Throughput Analysis of Interfering Packet Radio Networks

Popular Abstract in Swedish I avhandlingen presenteras ett matematiskt ramverk för analys av datagenomströmning i paket-baserade radionät som stör varandra. Tidigare forskning om prestanda i paketradionät täcker många olika system och aspekter. Tidigare publicerade arbeten har dock till stor del varit begränsade till fixa paketlängder. Ramverket som presenteras i avhandlingen tillåter detaljerad aIn this thesis, a probabilistic framework is presented and used for analysis of the throughput of interfering packet-based radio networks, referred to as packet radio networks (PRNs). Previous research on the performance of PRNs covers a wide variety of systems and aspects in varying levels of detail. However, the work presented in the literature has mostly been limited to fixed packet lengths. Th

On Bounds and Asymptotics of Sequential Monte Carlo Methods for Filtering, Smoothing, and Maximum Likelihood Estimation in State Space Models

This thesis is based on four papers (A-D) treating filtering, smoothing, and maximum likelihood (ML) estimation in general state space models using stochastic particle filters (also referred to as sequential Monte Carlo (SMC) methods). The aim of Paper A is to study the bias of Monte Carlo integration estimates produced by the so-called bootstrap particle filter. A bound on this bias which is inv

Iron-related luminescence centers in ZnWO4 : Fe

A systematic spectroscopic study of single ZnWO4 :Fe crystals with different iron concentrations has been performed under excitation by ultraviolet light, by synchrotron radiation or under photostimulation by near-infrared light. The luminescence of Fe3+-related centres has been studied. It is shown that iron centres of different types efficiently promote the formation of crystal defects at low te

Female gender is associated with higher incidence and more stable respiratory symptoms during adolescence

Childhood asthma and wheeze is more common among boys than girls, white the opposite is found in adults. The main objective was to study the incidence and the course of wheeze and asthma during adolescence with focus on gender differences. In addition, we explored associations between lifestyle factors at baseline and wheeze at follow-up. A total of 2399 adolescents answered validated questionnair

Membrane extraction in environmental chemical analysis

Membrane extraction techniques permit the application of classical liquid-liquid extraction (LLE) chemistry to instrumental and automated operation. Various shortcomings of LLE are overcome by membrane extraction techniques as they use none or very little organic solvents, high enrichment factors can be obtained and there are no problems with emulsions. A three phase SLM system (aq/org/aq), where

Activation of the canonical Wnt pathway leads to loss of hematopoietic stem cell repopulation and multilineage differentiation block

Wnt signaling increases hematopoietic stem cell self-renewal and is activated in both myeloid and lymphoid malignancies, indicating involvement in both normal and malignant hematopoiesis. We report here activated canonical Wnt signaling in the hematopoietic system through conditional expression of a stable form of beta-catenin. This enforced expression led to hematopoietic failure associated with