Some species of cyanobacteria form resting stages at the sediment surface when environmental conditions become unfavourable. As conditions turn more favourable, these resting stages hatch to the water phase, where the cells grow, reproduce, and sometimes form blooms. Since blooms of cyanobacteria have become an increasing threat to inland and brackish waters, it is important to assess the mechanis

This dissertation can be read on at least two levels. On one level it will deal with- how general patterns of cognitive perception set frames for and affect human action in history and how these patterns may change. A study on copper flat axes will serve as a foundation for this discussion. This examination of copper flat axes will, however, at the same time examplify some of the problems concerni

This thesis consists of three papers (Papers A-C) on problems in nonparametric functional estimation, in particular density and regression function estimation and deconvolution, under order assumptions. Pointwise limit distribution results are stated for the obtained estimators, which include isotonic regression estimates, nonparametric maximum likelihood estimates of monotone densities, estimates

Developmental instability and fluctuating asymmetry (FA) have become important topics in evolutionary biology. For example, it has been suggested that FA could be a useful tool for identification of genetic and environmental stress factors. This study used plants from each of six populations of Scabiosa canescens and Scabiosa columbaria grown under greenhouse conditions. I tested whether there was

The aim of this study was to investigate the usefulness of static spin-echo MR imaging at low field strength in evaluating postoperative pulmonary arterial supply. Twenty-seven patients operated on for complex congenital heart disease underwent cardiac MR imaging: 27 stenoses in 20 patients and 4 aneurysms were present in the material. Five of the overlooked stenoses were located in the ventricula

Objective. Peritoneal adhesions develop after almost all surgical interventions in the abdomen. We have developed an efficient treatment against post-surgical adhesions consisting of a combination of positively charged poly-L-lysine and negatively charged poly-L-glutamate. The aim of the present study was to further develop the concept of applying oppositely charged polypeptides in the prevention

Sampling methodology (e.g. population-based vs. clinical samples, anonymous self-reports vs. data collected as part of mandated treatment) affects the validity of conclusions drawn from research addressing the etiology of adolescent sexual offending. Studies of unselected samples allow testing of the generalizability of etiological models suggested from investigation of selected clinical or forens

OBJECTIVES. The authors studied complications of transpedicular stabilization methods. SUMMARY OF BACKGROUND DATA. One hundred and sixty-three consecutive transpedicular stabilization procedures were performed between January 1987 and December 1991. The indications for stabilization were trauma (33 cases), metastatic spinal disorder (30 cases), spinal stenosis (33 cases), spondylolisthesis (27 cas

We report growth of one-dimensional semiconductor nanocrystals, nanowhiskers, in which segments of the whisker with different composition are formed, illustrated by InAs whiskers containing segments of InP. Our conditions for growth allow the formation of abrupt interfaces and heterostructure barriers of thickness from a few monolayers to 100s of nanometers, thus creating a one-dimensional landsca

Background: Within 5 years following radical prostatectomy, between 15 and 60% of patients with pT3 prostate carcinomas show an increasing prostate-specific antigen (PSA) as a sign of local and/or systemic tumour progression. Adjuvant radiotherapy (RT) for positive margins (RI) aims to reduce residual tumour cells in the prostatic bed, thus possibly reducing the biochemical progression rate. Apart

We have investigated the characteristics of the currents in a pump driven fermionic Mach-Zehnder interferometer. The system is implemented in a conductor in the quantum Hall regime, with the two interferometer arms enclosing an Aharonov-Bohm flux Phi. Two quantum point contacts with transparency modulated periodically in time drive the current and act as beam splitters. The current has a flux-depe

The aim of this study was to test whether environmental enrichment alters the status and responsiveness of pituitary-adrenocortical and sympathetic-adrenomedullary hormones in rats. Previous studies have shown that rats kept in an enriched environment differ from those kept in standard cages in dendritic branching, synaptogenesis, memory function, emotionality and behaviour. In male Wistar rats ke

OBJECTIVE: To compare the average out-of-home (OH) consumption of foods and beverages, as well as energy intake, among populations from 10 European countries and to describe the characteristics of substantial OH eaters, as defined for the purpose of the present study, in comparison to other individuals. DESIGN: Cross-sectional study. Dietary data were collected through single 24-hour dietary recal

Popular Abstract in Swedish Denna avhandling innehåller fem essäer behandlande ett antal olika frågor inom området empirisk finansiell ekonomi. Genom användandet av kvantitativa metoder är syftet att studera praktiskt relevanta problem relaterade till hur finansiella marknader fungerar. Frågorna som tas upp sträcker sig från optionsprissättning och terminshedgning, över stokastisk volatilitets modThis thesis consists of five empirical essays dealing with different issues related to financial markets. Chapter 2 studies a new multivariate technique, Orthogonal GARCH, of forecasting large covariance matrices based on GARCH models. Orthogonal GARCH is built on principal component analysis and makes the creation of positive definite covariance matrices of arbitrary size possible. An important d

Earlier work has derived the storage complexity of the bounded distance decoder (BDD) for binary-channel convolutional codes. We extend this work to the Gaussian noise channel and to partial-response codes. We show that the storage requirement similar to(2(1-R) - 1)(-t) paths for rate-R convolutional codes over the binary channel becomes similar to2(2Rt) over the Gaussian channel, where the decode

Ultraviolet (UV) radiation is harmful to all life, and the ongoing depletion of the ozone layer is likely to affect interactions among both terrestrial and aquatic organisms. Some organisms have evolved adaptations to reduce radiation damage, such as the various types of protective pigmentation of freshwater zooplankton. However, strong pigmentation also increases vulnerability to visually hunting