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Acoustical properties of earplugs

Popular Abstract in Swedish En ny mätuppställning har utvecklats och tillämpats på öronproppar (hörselproppar). Mätuppställning gör det möjligt att skatta de akustiska egenskaperna i form av en så kallad tvåport. För objektiva mätningar på hörselskydd använder man normalt sett någon form av artificiellt huvud eller öra, med vars hjälp man mäter insättningsdämpningen. Denna insättningsdämpning beskIn this study an experimental setup for measurements of high impedance objects in ducts, yielding the acoustical Two-Port properties of the object, is applied to earplugs. A frequently used experimental setup for measuring objective acoustical properties of earplugs is that of artificial ears. Great effort is spent on duplicating the human ear. The acoustical properties of the earplug are thought

Families' needs when a child is long-term ill: A literature review with reference to nursing research.

This article reports a literature review which draws together findings targeting families' needs when a child is long-term ill. The databases PubMed and CINHAL were searched from 1999 to 2003 during February 2004. The search terms were child health care, family caregivers, and needs and combinations of these. The search was limited to articles published in English and the Scandinavian languages. T

The axial N-base has minor influence on Co-C bond cleavage in cobalamins

We have investigated the properties of cobalamin complexes with imidazolate using the density functional B3LYP method, In particular, we have compared imidazolate (Imm) with imidazole and 5,6-dimethylbenzimidazole (DMB), and studied how constraints in the axial Co-N bond length may affect the strength of the Co-C bond. The results show that the optimum Co-N-Imm bond is similar to0.2 Angstrom short

The effects of physical activity and estrogen treatment on rat fast and slow skeletal muscles following ovariectomy

Decreased estrogen production is associated with changes in the skeletal, cardiovascular and muscular systems. At the level of skeletal muscles, it has been shown that a reduction in force production occurs at menopause but the underlying mechanisms are still unknown. The aim of the study was to investigate the effects of ovariectomy on myosin heavy chain (MyHC) composition. Additionally, we studi

Sorption kinetics of naphthalene and phenanthrene in loess soils

A laboratory study was executed to investigate the effect of surfactants to enhance sorption of polycyclic aromatic hydrocarbon (PAH) contaminants in loess soil. Phenanthrene and naphthalene were chosen as organic contaminant indicators in loess soil modi. fied by the cation surfactant hexadecyltrimethylammonium (HDTMA) bromide. The kinetic behavior of sorption during transport in natural and modi

Frontotemporal dementia – Differentiation from Alzheimer's disease

Organic dementia is dominated by primary degenerative disorders such as Alzheimer’s disease (AD) and frontotemporal dementia (FTD). FTD is a distinct clinical syndrome with behavioural, personality, emotional and language disturbances preceding the cognitive decline. This clinical presentation is distinctly different from that of AD which is characterized by early cognitive changes, such as memory

Objective monitoring of nasal airway inflammation in rhinitis

Allergic rhinitis is an inflammatory nasal disorder in which a range of different cells participates. A variety of approaches has been used to monitor nasal inflammation objectively to investigate disease processes and to evaluate the effect of therapeutic intervention. These approaches include nasal lavage, nasal cytology, and nasal biopsy, together with the more recently established measurement

Analysis of DFT-based channel estimators for OFDM

In this paper we analyze the performance of three low-complexity channel estimators, based on the discrete Fourier transform (DFT), for orthogonal frequency-division multiplexing (OFDM) systems. Estimators of this type have been analyzed for discrete-time channels, and we extend this analysis to continuous-time channels. We present analytical expressions for their mean-squared error (MSE) and eval

Modeling the acid-base properties of bacterial surfaces: A combined spectroscopic and potentiometric study of the gram-positive bacterium Bacillus subtilis

In this study, macroscopic and spectroscopic data were combined to develop a surface complexation model that describes the acid-base properties of Bacillus subtilis. The bacteria were freeze-dried and then resuspended in 0.1 M NaCl ionic medium. Macroscopic measurements included potentiometric acid-base titrations and electrophoretic mobility measurements. In addition, ATR-FTIR spectra of wet past

Water balance change for a re-vegetated xerophyte shrub area

Water balances for a re-vegetated xerophyte shrub (Caragana korshinskii) area were compared to that of a bare surface area by using auto-weighing type lysimeters during the 1990-1995 growing seasons at the southeast Tengger Desert, Shapotou, China. The six-year experiment displayed how major daily water balance components might vary for a bare and a re-vegetated sand dune area. Evapotranspiration

Effects of natural and sexual selection on adaptive population divergence and premating isolation in a damselfly

The relative strength of different types of directional selection has seldom been compared directly in natural populations. A recent meta-analysis of phenotypic selection studies in natural populations suggested that directional sexual selection may be stronger in magnitude than directional natural selection, although this pattern may have partly been confounded by the different time scales over w

Loyal Speed Adaptation Speed limitation by means of an active accelerator and its possible impacts in built-up areas

Traditional measures for improved traffic safety need to be complemented by modern technologies in the struggle to reduce the consequences of traffic accidents all over the world. This thesis introduces the Loyal Speed Adaptation (LSA) function based on recent developments in the area of Intelligent Transport Sys-tems to support the vehicle drivers in not using inappropriate or excessive speeds, w

Airway symptoms and lung function in pipelayers exposed to thermal degradation products from MDI-based polyurethane.

OBJECTIVES: To study the prevalence of symptoms from the eyes and the upper and lower respiratory tract, lung function, and immunological sensitisation towards isocyanates in pipelayers exposed to thermal degradation products from methylene diphenyl diisocyanate (MDI)-based polyurethane (PUR). MATERIAL AND METHODS: 50 presently active and 113 formerly active pipelayers were examined. Also, 65 unex