Sökresultat

Filtyp

Din sökning på "*" gav 533079 sökträffar

Levels of C-14 in the terrestrial environment in the vicinity of two European nuclear power plants

Radiocarbon is produced in all types of nuclear reactors. Most of the C-14 released into the environment is in the form of gaseous emissions. Recent data on the C-14 concentration found in terrestrial samples taken in the vicinity of nuclear power plants in Romania and Lithuania are presented. We found increased C-14 levels in the surroundings of both power plants. At the Romanian power plant Cern

Recursive estimation of parameters in Markov-modulated Poisson processes

A hidden Markov regime is a Markov process that governs the time or space dependent distributions of an observed stochastic process. Recursive algorithms can be used to estimate parameters in mixed distributions governed by a Markov regime. Here we derive a recursive algorithm for estimation of parameters in a Markov-modulated Poisson process also called a Cox point process. By this we mean a doub

Development of Adenoviral Vectors for Studying Hematopoietic Stem Cell Function

Popular Abstract in Swedish Blodet innehåller några av de mest grundläggande komponenterna för mänskligt liv. Med hjälp av hjärtats pumpkraft transporterar röda blodkroppar ut syre från lungorna till de mest avlägsna delarna av kroppen via gradvis tunnare blodkärl. Livshotande blödningar stoppas via blodplättarnas koagulerande förmåga och läkande egenskaper, medan de vita blodkropparna bekämpar inHematopoietic stem cells (HSCs) are defined by their capacity to self-renew and differentiate into all hematopoietic cell lineages. Postnatally, HSCs reside predominantly in the bone marrow and are relatively rare, but important cells because of their therapeutic potential in bone marrow transplantation protocols and in their involvement in the origin of certain leukemias. To study how various gen

BTKBASE - A DATABASE OF XLA-CAUSING MUTATIONS

X-linked agammaglobulinemia (XLA) is an immunodeficiency caused by mutations in the gene coding for Bruton's tyrosine kinase (BTK). A database (BTKbase) of BTK mutations has been compiled, and its use and the resultant information are discussed in this article.

Presence or absence of counterion specificity in the interaction of alkylammonium surfactants with alkylacrylamide gels

Patterns in the interaction of cationic surfactants with nonionic polymer gels, which were inferred from a recent study from our laboratory, are confirmed by measurements of a series of alkylammonium surfactants with different counterions with a series of alkyl acrylamide gels of increasing hydrophobicity. Two swelling patterns were observed: Either the swelling continued above the surfactant crit

Core-level spectroscopy study of the Li/Si(111)-3 x 1, Na/Si(111)-3 x 1, and K/Si(111)-3 x 1 surfaces

In this article we report Si 2p core-level spectroscopy results from the alkali (Li, Na, and K) induced Si(111)-3 x 1 reconstructions. The experimental results are compared to the theoretical honeycomb-chain channel (HCC) model for,the 3 x 1 reconstruction using density functional theory (DFT) to calculate core-level shifts using both initial and final-state calculation schemes. Si 2p core-level s

Occupational exposure to hexahydrophthalic anhydride: air analysis, percutaneous absorption, and biological monitoring

Urinary hexahydrophthalic acid (HHP acid) levels were determined in 20 workers occupationally exposed to hexahydrophthalic anhydride (HHPA) air levels of 11-220 micrograms/m3. The levels of HHP acid in urine increased rapidly during exposure and the decreases were also rapid after the end of exposure. The elimination half-time of HHP acid was 5 h, which was significantly longer than in experimenta

New antimicrobial peptide active against Gram-positive pathogens

Background & objectives: Human and animal cystatins have been shown to inhibit the replication of certain viruses and bacteria, though it is not directly demonstrated that the effects are due to protease inhibitory capacity of the cystatins. We report antibacterial properties of a novel antimicrobial peptidyl derivative, (2S)-2-(N-alpha-benzyloxycarbonyl-arginyl-leucylamido)-1-(E)-cinnamoyla m

Ecological implications of the production of toxic substances by fish killing phytoplankton species grown under variable N:P-ratios

The influence of different nutrient conditions on the production of toxins was studied in certain fishkilling haptophytes (e.g. Prymnesium parvum and Chrysochromulina polylepis). The toxicity was strongly influenced by the nutrient status of the medium, resulting in a significantly higher toxicity when grown under nutrient limited conditions compared to nutrient replete conditions. This occurred i

Applications of Rice's formula in oceanographic and environmental problems

Popular Abstract in Swedish Den här avhandlingen består av fem papper (A-E) som samtliga är tillämpningar av Rice's formel. Tillämpningsområdena är inom oceanografi och miljö. De tre första papperna behandlar egenskaper hos mötande havsvågor, det vill säga vågor som ett fartyg möter när det seglar på havet. Papper A syftar till att hitta en formel för att räkna ut intensiteten av sådana vågor. SpThis thesis is based on five papers (A-E), all treating various applications of Rice's formula. The areas of application are oceanographic and environmental problems. The first three papers treat properties of encountering waves, that is, waves that a ship encounters while sailing on the ocean. Paper A addresses the problem of computing the intensity of such waves and, in particular, the intensit

Arrhythmia as a result of poor intercellular coupling in the sinus node: A simulation study

The effects of reduced intercellular coupling in the sinus node were investigated by means of simulations. Coupling was reduced both uniformly, and by introducing localized interaction blocks. In either case, model sinus node element networks typically splitted into frequency domains. These were defined as groups of neighbour elements which all attained the same mean firing frequency. In systems,

Work related shoulder disorders: quantitative exposure-response relations with reference to arm posture

Aims: To determine quantitative exposure-response relations between work with highly elevated arms and supraspinatus tendinitis, shoulder pain with disability, and shoulder pain without disability. Methods: A cross sectional study was conducted in a historical cohort of 1886 males from three occupational groups. Exposure measurements were performed for four consecutive working days in a random sam

Att binda djur och väva strid. Om djurornamentikens innebörder.

Animal ornamentation was a dominating expression of art in Scandinavia during the period c. 250-1250 AD. In this chapter i am trying to nuance and deepen our understanding of animal ornamentation as a possible cognitive expression. By relating its images to the metaphorical language of early medieval skaldic poetry I suggest that its meanings have been tightly knit to an ideology of honour and war

Fluorescence depolarization dynamics in the B850 complex of purple bacteria

The fluorescence anisotropic decay is modeled for the B850 bacteriochlorophyll a complex of the purple bacterium Rhodopseudomonas acidophila. Structural information is combined with experimental data to derive a Hamilton operator which models the S-0-S-1 excitation energy transfer between the pigments as well as the energy dissipation into the protein environment. The time-resolved fluorescence si

Optimal on-line scheduling of multiple control tasks: A case study

We study the problem of dynamically scheduling a set of state-feedback control tasks controlling a set of linear plants. We consider an on-line non-preemptive scheduling policy that is optimal in the sense that it minimizes a quadratic performance criterion for the overall system. The optimal scheduling decision at each point in time is a function of the states of the controlled plants. To be able

LICS - Language for Implementation of Control Systems

This report describes a language and an interactive environment, called LICS, for implementation of control systems and dynamic modelling. It used graphics for representation of the structural properties: hierarchical decomposition, interconnection structure, and structure of the interfaces. The decomposition and interconnection structures are described by block diagrams. Low level modules are des

Cancer prevalence in European registry areas

BACKGROUND: Information on cancer prevalence is of major importance for health planning and resource allocation. However, systematic information on cancer prevalence is largely unavailable. MATERIALS AND METHODS: Thirty-eight population-based cancer registries from 17 European countries, participating in EUROPREVAL, provided data on almost 3 million cancer patients diagnosed from 1970 to 1992. Sta