Sökresultat

Filtyp

Din sökning på "*" gav 532880 sökträffar

Charged particle multiplicity in three-jet events and two-gluon systems

The charged particle multiplicity in hadronic three-jet events from Z decays is investigated. The topology dependence of the event multiplicity is found to be well described by a modified leading logarithmic prediction. A parameter fit of the prediction to the data yields a measurement of the colour factor ratio C-A/C-F with the result C-A/C-F = 2.261 +/- 0.014(stat). +/- 0.036(exp). +/- 0-066(the

Dinoflagellater – hopplock från livets smörgåsbord

The dinoflagellates constitute a group within the protistan supergroup Alveolata, and can be referred neither to the plant nor the animal kingdom. They swim about using two flagella and orient using various stimuli. About half of the species are capable of oxygenic photosynthesis, but most of them complement this with capture of prey. Some live entirely by capturing small organisms, others are par

The FERRUM Project: Experimental oscillator strengths of the UV 8 multiplet and other UV transitions from the y6P levels of Fe II

We report on experimental branching fractions (BFs) for 19 transitions from the three 3d 5( 6S)4s4p( 3P) y6P levels in Fe II, measured in Fourier transform spectra of a Penning discharge lamp and a hollow cathode lamp. The transition wavelengths span the interval between 1600 and 2850 Å. Absolute oscillator strengths ( f-values) have been derived by combining the BFs with experimental radiative li

MR imaging in clinically suspected acute cholecystitis. A comparison with ultrasonography

PURPOSE: The diagnostic value of fast pulse sequences in MR imaging was compared with US in patients with clinically suspected acute cholecystitis. MATERIAL AND METHODS: In a prospective study of 94 patients, 35 were examined with both MR and US within 24 h. RESULTS: MR diagnoses were acute cholecystitis in 23, gallbladder and common bile duct stones in 3, other pathologic conditions of the abdome

Stochastic population dynamics: The Poisson approximation

We introduce an approximation to stochastic population dynamics based on almost independent Poisson processes whose parameters obey a set of coupled ordinary differential equations. The approximation applies to systems that evolve in terms of events such as death, birth, contagion, emission, absorption, etc., and we assume that the event-rates satisfy a generalized mass-action law. The dynamics of

Vegetation and land-use in the Småland Uplands, southern Sweden, during the last 6000 years

Palaeoecological methods were applied to peat and sediment cores recovered from one bog (Bråtamossen) and two lakes (Avegöl and Femtingagölen) in the Småland Uplands, southern Sweden. The general aim was to reconstruct the landuse and vegetation history for the last 6000 years in this agriculturally marginal region. The main technique was pollen analysis, which was complemented by mineral magnetic

Influence of liver cancer on lipid and lipoprotein metabolism

Liver plays a key role in the metabolism of plasma apolipoproteins, endogenous lipids and lipoproteins. Hepatocellular carcinoma (HCC) is one of the most common fatal malignant tumors in China and in other Southeast Asian countries. This has been attributed to the high incidence of hepatitis B infection. Hepatitis B proteins, such as the hepatitis B X protein (HBx) that is large hepatitis B surfac

Quantum Chemistry Can Locally Improve Protein Crystal Structures

We have re-refined the X-ray structure of the heme site in cytochrome c553, supplementing the crystallographic data with quantum chemical geometry optimizations, instead of the molecular mechanics force field used in standard crystallographic refinement. By comparing the resulting structure, obtained using medium-resolution data (170 pm), with an atomic-resolution structure (95 pm) of the same pro

Delineation of the earliest lineage commitment steps of haematopoietic stem cells: new developments, controversies and major challenges

Purpose of review This review addresses recently reported evidence for alternative cellular pathways for haematopoietic stem cell lineage commitment. Recent findings Using various approaches, several laboratories suggested the existence of adult as well as foetal multipotent progenitor cells with combined B cell, T cell and granulocyte/macrophage potential, but little or no megakaryocyte/erythroid

A magnetostratigraphic comparison between 14C years and varve years during the late Weichselian, indicating significant differences between the time-scales

A 14C-dated magnetostratigraphy of absolute declination and inclination between 12500 and 10000 14C yr BP was recently developed for southern Sweden. Recently also the Swedish geochronological time-scale, based on c. 11 500 annually deposited clay-varves, was connected with the present. It should therefore be possible to compare the two chronologies with a reliable magnetostratigraphic record in a

Rättighet och Rättvisa : Användbarhet av rättighet och rättvisa i sociala projekt

Popular Abstract in Swedish I de hänvisningar som används i ett stort antal sociala projekt för att målet skall uppnås hittas rättighet och rättvisa som centrala diskursiva enheter i en återkommande använd tankemodell. I flera av dessa projekt blir resultatet, gång efter annan, utebliven framgång. Men den samma rätta tankemodellen förblir en självklar utgångspunkt. De upprepade krigen mot fattigdoIn the references invoked by a large number of social projects to achieve their goals, one can find rights and justice as central discursive units in a frequently recurring thought model. In several of these projects the result, time after time, is lack of success. But the same right thought model continues to be taken for granted as a point of departure. The repeated wars on poverty in the USA ex

On the simulation of iterated Itô integrals

We consider algorithms for simulation of iterated Itô integrals with application to simulation of stochastic differential equations. The fact that the iterated Itô integral I_{ij}(t_n,t_n+h)=\int_{t_n}^{t_n+h} \int_{t_n}^{s} dW_{i}(u)dW_{j}(s) conditioned on W_i(t_n+h)-W_i(t_n) and W_j(t_n+h)-W_j(t_n), has an infinitely divisible distribution is utilised for the simultaneous simulation of $I_{ij}(

Effektiviserad utredning möjlig vid misstänkt akut koronart syndrom. Nya undersökningsmetoder kan ge bättre vårdkvalitet och spara resurser

The immediate evaluation of patients with suspected acute coronary syndrome (ACS) in the emergency department (ED) has remained almost unchanged for decades. At the same time, therapy for established ACS has undergone a remarkable and successful change towards early active intervention. Studies show that 7 out of 10 patients admitted with a suspicion of ACS do not have it, and that 2-5% of the pat

Estimating water content from electrical conductivity measurements with short time-domain reflectometry probes

Time domain reflectometry (TDR) is a widely used technique for measuring the dielectric constant (K-a) and bulk electrical conductivity (sigma(a)) of soil. The K-a measurement can be converted to water content (theta) by means of a (soil specific) calibration. Since the accuracy of the K-a measurement is dependent on the TDR probe length, probes longer than about 0.1 m are preferred. However, shor

Effects of selective ETB-receptor stimulation on arterial, venous and capillary functions in cat skeletal muscle

1. This paper describes, in quantitative terms, the in vivo effects of two selective ETB-receptor agonists (IRL 1620 and BQ 3020) on vascular resistance (tone) in the following consecutive sections of the vascular bed of sympathectomized cat skeletal muscle: large-bore arterial resistance vessels (> 25 microns), small arterioles (< 25 microns) and the veins. The effects on capillary pressure trans

The twofold cost of sex unfolded

Question: Considering ecological factors and life history, how easy is it for sexual reproduction (as a strategy) to invade and persist in a population where all individuals are reproducing asexually? Mathematical method: We use a population growth equation that despite its simplicity captures several relevant ecological parameters: age-specific survival, differential birth rates, as well as both