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Optical Studies of Polytypism in GaAs Nanowires

Semiconductor nanowires are often regarded as having potential to be building blocks for novel applications. Their geometry allows defect-free combinations of materials that have a high degree of lattice mismatch. III-V semiconductor nanowires can also be grown in the wurtzite crystal phase, which is not stable in bulk material or thin films. The atomic arrangement differs between wurtzite and zin

Evolution of olfaction in Lepidoptera and Trichoptera : Gene families and antennal morphology

Resultaten i denna avhandling ökar vår kunskap om hur evolutionen av feromondetektering hos fjärilar gått till.Luktsinnet är viktigt för de flesta djur, inklusive människor, hundar, insekter och många andra. Hos insekter, särskilt nattfjärilar och flugor, används luktsinnet för att hitta parningspartners, föda, äggläggningsställen och att undkomma fiender.Feromoner är kemikalier som produceras ochIn moths, females produce sex pheromone compounds to attract males over a long distance for mating. The antennae of moths and many other insects have specialized odorant receptors (ORs), called pheromone receptors (PRs), to sense the pheromone compounds and they group in a monophyletic clade (PR clade).In this thesis, I investigated and compared various components of the olfactory system in differ

The value of small arable habitats in the agricultural landscape : Importance for vascular plants and the provisioning of floral resources for bees

Small remnants of non-arable habitat within the farmland mosaic are considered important for the conservation of farmland biodiversity, but their contribution to landscape-scale species richness is poorly understood. In the present study, we examined the relative contributions of different habitat types to the landscape-scale species richness of vascular plants within farmland of varying landscape

Heat transfer enhancement and turbulent flow in a high aspect ratio channel (4:1) with ribs of various truncation types and arrangements

Ribs are often employed in internal cooling passages of turbine blades to augment heat transfer with cooling air flowing through the internal ribbed passages. The present work concentrates on truncated ribs to improve thermal performances with continuous ribs in a high aspect ratio channel. With various truncation types and arrangements of truncated ribs, the optimized thermal performance of ribbe

A tunable electron beam source using trapping of electrons in a density down-ramp in laser wakefield acceleration

One challenge in the development of laser wakefield accelerators is to demonstrate sufficient control and reproducibility of the parameters of the generated bunches of accelerated electrons. Here we report on a numerical study, where we demonstrate that trapping using density down-ramps allows for tuning of several electron bunch parameters by varying the properties of the density down-ramp. We sh

Source deghosting by depth apparition

Marine seismic data are distorted by ghosts as waves propagating upward reflect downward from the sea surface. Ghosts appear on the source side and the receiver side. However, whereas the receiver-side ghost problem has been studied in detail, and many different solutions have been proposed and implemented commercially, the source-side ghost problem has remained largely unsolved with few satisfact

Förutsättningar för att inrätta pedagogiska akademier vid fakulteter som idag saknar sådana

I Lunds universitets strategiska plan för 2012-2016 framhålls att man vill ”vidareutveckla det akademiska lärarskapet”. All utbildning vid lärosätet ska hålla högsta kvalitet och man ska erbjuda attraktiva och akademiskt framstående lärandemiljöer. Detta åstadkoms bland annat genom att universitetets lärare kan ”arbeta med ett forskande förhållningssätt, både i förhållande till studenternas lärand

Preventing sintering of nanoclusters on graphene by radical adsorption

Metal nanoclusters, supported on inert substrates, exhibiting well-defined shapes and sizes in a broad range of temperatures are a major object of desire in nanotechnology. Here, a technique is presented that improves the thermal stability of monodisperse and crystalline transition metal nanoclusters grown in a regular array on metal-supported graphene. To stabilize the clusters after growth under

Fumarate Hydratase Deletion in Pancreatic β Cells Leads to Progressive Diabetes

We explored the role of the Krebs cycle enzyme fumarate hydratase (FH) in glucose-stimulated insulin secretion (GSIS). Mice lacking Fh1 in pancreatic β cells (Fh1βKO mice) appear normal for 6–8 weeks but then develop progressive glucose intolerance and diabetes. Glucose tolerance is rescued by expression of mitochondrial or cytosolic FH but not by deletion of Hif1α or Nrf2. Progressive hyperglycem

Modeling Parkinson’s disease pathology by combination of fibril seeds and α-synuclein overexpression in the rat brain

Although a causative role of α-synuclein (α-syn) is well established in Parkinson’s disease pathogenesis, available animal models of synucleinopathy do not replicate the full range of cellular and behavioral changes characteristic of the human disease. This study was designed to generate a more faithful model of Parkinson’s disease by injecting human α-syn fibril seeds into the rat substantia nigr

Inheritance of a hair character in Helianthemum oelandicum var. canescens and allele frequencies in natural populations

Helianthemum oelandicum var. canescens (Hartm.) Fr. is an endemic taxon with a restricted distribution (less than 10 km2) in the southernmost part of the Baltic island of Öland, SE, Sweden. The taxon varies with respect to stellate hairs. Most plants can be classified into two morphs, the stellated morph (with a dense carpet of stellate hairs on the abaxial surface of the leaves) and the bristled

Professionalism between profession and governance : how university teachers’ professionalism shapes coordination

The purpose of this article is to analyze how university teachers’ professionalism shapes the coordination processes in higher education institutions (HEIs). By developing an innovative framework, which combines governance theories and theories about professionalization, we found that university teachers’ roles in coordination with governance actors in HEIs follow two different logics: to comply w

Vitamin K and cancer

Subclinical vitamin K deficits refer to carboxylation defects of different types of vitamin K-dependent hepatic and extrahepatic so-called Gla proteins without prolongation of the prothrombin time. This condition has been reported in different clinical situations due to insufficient supply or malabsorption of vitamin K as well as drug interactions. This review discusses the effects of different vi

Rapid and Green Separation of Mono- and Diesters of Monochloropropanediols by Ultrahigh Performance Supercritical Fluid Chromatography-Mass Spectrometry Using Neat Carbon Dioxide as a Mobile Phase

This study demonstrates the effect of column selectivity and density of supercritical carbon dioxide (SC-CO2) on the separation of monochloropropanediol (MCPD) esters, known as food toxicants, using SC-CO2 without addition of cosolvent in ultrahigh performance supercritical fluid chromatography-mass spectrometry (UHPSFC-MS). This study shows that over 20 2-monochloropropanediol (2-MCPD) and 3-mono

Hyperparameter Selection for Group-Sparse Regression: A Probabilistic Approach

This work analyzes the effects on support recovery for different choices of the hyper- or regularization parameter in LASSO-like sparse and group-sparse regression problems. The hyperparameter implicitly selects the model order of the solution, and is typically set using cross-validation (CV). This may be computationally prohibitive for large-scale problems, and also often overestimates the model

Novel in Situ Techniques for Studies of Model Catalysts

ConspectusMotivated mainly by catalysis, gas-surface interaction between single crystal surfaces and molecules has been studied for decades. Most of these studies have been performed in well-controlled environments and have been instrumental for the present day understanding of catalysis, providing information on surface structures, adsorption sites, and adsorption and desorption energies relevant

Online Group-Sparse Regression Using the Covariance Fitting Criterion

In this paper, we present a time-recursive implementation of a recent hyperparameter-free group-sparse estimation technique. This is achieved byr eformulating the original method, termed group-SPICE, as a square-root group-LASSO with a suitable regularization level, for which a time-recursive implementation is derived. Using a proximal gradient step for lowering the computational cost, the propose

Quantum-state-selective decay spectroscopy of 213Ra

An experimental scheme combining the mass resolving power of a Penning trap with contemporary decay spectroscopy has been established at GSI Darmstadt. The Universal Linear Accelerator (UNILAC) at GSI Darmstadt provided a 48Ca beam impinging on a thin 170Er target foil. Subsequent to velocity filtering of reaction products in the Separator for Heavy Ion reaction Products (SHIP), the nuclear ground