Sökresultat

Filtyp

Din sökning på "*" gav 528293 sökträffar

Detectors for the European Spallation Source

The European Spallation Source (ESS) in Lund, Sweden will become the world's leading neutron source for the study of materials by 2025. First neutrons will be produced in 2019. It will be a long pulse source, with an average beam power of 5 MW delivered to the target station. The pulse length will be 2.86 ms and the repetition rate 14 Hz. The ESS is presently in a design update phase, which ends i

Evaluating a traditional medicine policy in South Africa: phase 1 development of a policy assessment tool.

BACKGROUND: Policies that empower individuals and communities may be appropriate for public health, and more broadly. Simple, transparent and acceptable tools are therefore required to evaluate policies from an empowerment perspective. In 2008, the South African Department of Health (DOHSA) drafted a policy to endorse the integration of African Traditional Medicine (ATM) into the public health sec

The pupils and optical systems of gecko eyes

The nocturnal helmet gecko, Tarentola chazaliae, discriminates colors in dim moonlight when humans are color blind. The sensitivity of the helmet gecko eye has been calculated to be 350 times higher than human cone vision at the color vision threshold. The optics and the large cones of the gecko are important reasons why they can use color vision at low light intensities. Using photorefractometry

Prediagnostic Circulating Vitamin D Levels and Risk of Hepatocellular Carcinoma in European Populations: A Nested Case-Control Study

The association between vitamin D status and hepatocellular carcinoma (HCC) has not been well investigated, despite experimental evidence supporting an important role of vitamin D in liver pathophysiology. Our objective was to investigate the association between prediagnostic circulating 25-hydroxyvitamin D [25(OH)D] serum levels and the risk of HCC in a prospective, nested case-control study amon

PSYCHO-PEDAGOGICAL WORK AMONG INDIVIDUALS WITH AUTISM SPECTRUM DISORDERS IN COMMUNITY-BASED ACCOMMODATION. Development and psychometric testing of the Environmental Rating Scale Questionnaire (ERS-Q) for assessment of residential programmes.

The increased prevalence of individuals with Autism Spectrum Disorders (ASD) challenges society to evaluate the quality and efficacy of community based psycho-pedagogical programmes in order to achieve progress and to attain an acceptable level of quality of life for its citizens. The overarching aim of this thesis was to gain knowledge about staff’s pedagogical work and to provide a method for as

Using computed tomography and digital radiography of the human body to visualize metal fragments from bomb explosions – A preliminary report

A thoracic phantom, with embedded fragments of uranium (U) and iron (Fe) of different sizes, was imaged with digital radiography, standard-dose CT and low-dose CT and the detectable size of the fragments was recorded. U and Fe fragments were detected in diameters down to 100 mu m and 300 mu m, respectively with the standard-dose CT and digital radiography. The size limit using the low-dose CT was

Targeting human papillomavirus to reduce the burden of cervical, vulvar and vaginal cancer and pre-invasive neoplasia: establishing the baseline for surveillance.

Infection with high-risk human papillomavirus (HPV) is causally related to cervical, vulvar and vaginal pre-invasive neoplasias and cancers. Highly effective vaccines against HPV types 16/18 have been available since 2006, and are currently used in many countries in combination with cervical cancer screening to control the burden of cervical cancer. We estimated the overall and age-specific incide

Amorphous Silica Preservation in an Anthropogenic Soil: An Explorative Study of "Plaggen" Soils

Amorphous Silica (ASi) is present in considerable amounts in most soils and serves as a (micro-)nutrient for many plants. However, our understanding of the response of this important nutrient pool to human or natural disturbances is still very limited. One of the reasons for this is the long time scales involved. This explorative study focuses on the effect of a historical agricultural system, cal

14C and 10Be around 1650 cal BC

There is a debate about the date of the Minoan eruption of Santorini as reconstructed from a branch of an olive tree that was buried alive in trephra on Santorini2 and the dating of an ice core horizon attributed to this eruption.3 The olive branch was 14C-wiggle matched to the 14C calibration curve and yielded an age range of 1627-1600 bc4 while the counting of annual layers in the Greenland ice

Investigation of different valve geometries and valve timing strategies and their effect on regenerative efficiency for a pneumatic hybrid with variable valve actuation

In the study presented in this paper a single-cylinder Scania D12 diesel engine has been converted to work as a pneumatic hybrid. During pneumatic hybrid operation, the engine can be used as a 2-stroke compressor for generation of compressed air during vehicle deceleration and during vehicle acceleration the engine can be operated as an air-motor driven by the previously stored pressurized air. T

Influence of strut inertia on the vibrations in initially symmetric Gough-Stewart Platforms-an analytical study

Consideration of strut inertia can have significant influence on the modal behavior of a Gough-Stewart Platform (GSP). However, in the literature, the strut inertia has not yet been taken into account in its vibration study with a parametric approach. In this paper, we present a fully parametric approach to formulate the damped vibrations of GSPs taking into account the strut masses and moments of

Auger electron and photoabsorption spectra of glycine in the vicinity of the oxygen K-edge measured with an X-FEL

We report the first measurement of the near oxygen K-edge auger spectrum of the glycine molecule. Our work employed an x-ray free electron laser as the photon source operated with input photon energies tunable between 527 and 547 eV. Complete electron spectra were recorded at each photon energy in the tuning range, revealing resonant and non-resonant auger structures. Finally ab initio theoretical

Optimal antenna currents for Q, superdirectivity, and radiation patterns using convex optimization

The high Q-factor (low bandwidth) and low efficiency make the design of small antennas challenging. Here, convex optimization is used to determine current distributions that provide upper bounds on the antenna performance. Optimization formulations for maximal gain Q-factor quotient, minimal Q-factor for superdirectivity, and minimum Q for given far-fields are presented. The effects of antennas em

Observations of temperature stability of γ-zirconium hydride by high-resolution neutron powder diffraction

The phase evolution in a zirconium–50 deuterium (Zr–50D, at.%) alloy system during thermal cycling has been investigated using in situ high-resolution neutron powder diffraction. The results showed that the peritectoid reaction α-Zr + δ-ZrD → γ-ZrD previously suggested to occur at high temperatures does not take place in the system. Slow cooling, from high temperatures (≥520 K) to room temperature

Hollow-Fibre Liquid-Phase Microextraction for the Determination of Polycyclic Aromatic Hydrocarbons in Johannesburg Jukskei River, South Africa

A simple, rapid and environmentally friendly hollow-fibre liquid-phase microextraction (HF-LPME) technique was developed for the quantitative determination of polycyclic aromatic hydrocarbons (PAHs) in aqueous samples. GC-MS was then used as the method of analysis. The HF-LPME technique involves extraction of PAHs from a 20-mL sample containing 20 % acetonitrile as a modifier. The PAHs were extrac