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We study the rapid decrease of peak gain in resonant-phonon THz Quantum Cascade Lasers with increasing temperature. The effect of various microscopic scattering processes on the gain profile as a function of temperature is discussed. We argue that increased broadening, prim arily due to increased impurity scattering, and not diminishing population inversion, is the main reason for the reduction of
Streptomycetes are mycelial bacteria that resemble filamentous fungi in their apical growth, branching, and morphogenetic development. One inroad into the largely unknown mechanisms underlying this prokaryotic growth polarity is provided by Streptomyces DivIVA, a protein localized at hyphal tips and involved in tip extension. Another aspect is a proposed migration of nucleoids. During sporulation,
The structure and stability of the lamellar liquid crystal formed by the surfactant sodium bis-2ethylhexyl sulfosuccinate (AOT) in water is perturbed by small amounts of the substituted acrylamides N-isopropyl, N,N-diethyl, N-acryloylmorpholine, and N,N-dimethyl methacrylamide, as revealed by small angle X-ray scattering (SAXS), deuterium NMR, and microscopy. These molecules are water soluble and
Current treatments of osteoarthritis (OA) focus on pain and loss of joint function. When these interventions fail, the destroyed joint is replaced by implants of metal, plastic and ceramics. In the future, we need to detect cartilage loss before it is too severe, prevent further loss and stimulate regrowth of lost cartilage. Research in tissue engineering can help us understand the complex require
Albinism in birds is thought to result from the expression of recessive alleles that disrupt melanin pigmentation at feather development. We have studied great reed warblers Acrocephalus arundinaceus in a recently founded and increasing population in Sweden during 15 years for the presence of birds with albinistic feathers. The study population was founded in 1978 and the few cases of albinism was
This paper presents some improvements of the differential equation algorithm for transmission line protection. The improvements are: fault classification; new filtering; new algorithm for three-phase faults. Simulation results indicate a nominal operation time of 5-7 ms for three-phase faults and slightly higher for other fault types.
Glucagon-like peptide-1 (GLP-1), a future treatment for type 2 diabetes, is efficiently degraded by the enzyme dipeptidyl peptidase IV (DPP IV), yielding the major metabolite GLP-1-(9-36)-amide. In this study, we examined the potential glucose lowering effect of GLP-1(9-36)-amide in mice and found that GLP-1-(9-36)-amide (3 and 10 nmol/kg) did not affect insulin secretion or glucose elimination wh
Machine learning clustering techniques are used to characterize and, after the training phase, to identify phases within an ignition process. Forth e ethanol mechanism used in this paper, four physically identifiable phases were found and characterized: the initiation phase, preignition phase, ignition phase, and the postignition phase. The clustering is done with respect to fuzzy logic predicates
1. We investigated age-related changes in two reproductive traits (laying date and annual fecundity) in barn swallows Hirundo rustica L. using a mixed model approach to di-stinguish among between- and within-individual changes in breeding performance with age. 2. We tested predictions of age-related improvements of competence (i.e. constraint hypothesis) and age-related progressive disappearance o
Blood and serum samples from 372 15-year-old adolescents were collected in two cities in Sweden and analyzed by inductively coupled plasma mass spectrometry (ICP-MS). The objective was to (1) determine the levels of 13 elements in blood and serum from the teenagers; and (2) for each element, investigate the correlation between the concentrations in blood and serum. The concentrations in blood and
In this paper we will give an overview of some recent results which display a connection between commutativity and the ideal structure in algebraic crossed products.
Ten healthy extremely pre-term (EPT) children, born before gestational week 29, were tested at age 10 using mismatch negativity (MMN) and a three-tone odd-ball task; the results were then compared to age-matched full-term controls. We found no difference in MMN. By contrast, EPT children had generally shorter N1 latencies and larger P2 amplitudes, possibly indicating a more stimulus-driven respons
Symptoms of infection and tissue pathology are caused by the host response; not by the microbe per se. The same response is also critical for the defence and is needed to clear infection. It is therefore essential to understand how the host response is activated and to identify the critical effector mechanisms of the defence. We have studied these issues in the urinary tract infection (UTI) model.
Poly(ethylene glycol) monomethyl ethers (MPEG) were grafted on copolymers of maleic anhydride and styrene, methyl methacrylate, and ethylhexyl methacrylate, respectively. Hydrolysis of the remaining anhydride residues gave graft copolymers carrying a large number of carboxylic acid groups along the main chains. The properties in aqueous solutions of these graft copolymers were studied with respect
In order to disentangle the causes of variations in water chemistry among European shallow lakes, we performed standardised sampling programs in 86 lakes along a latitudinal gradient from southern Spain to northern Sweden. Lakes with an area of 0.1 to 27000 ha and mean depth of 0.4-5.6 m located in low to high altitudes were investigated within the EC project ECOFRAME 1-4 times during June-October
A method for modelling reflectionless conductive dispersive media is presented. The media are either half-spaces or finite dispersive slabs with a spatially varying impedance. The problem of finding reflectionless media for plane waves at normal incidence is formulated as an inverse problem where the constitutive relation is to be determined as a function of depth given a reflection kernel which i
