A Comprehensive Model of a Doubly Fed Induction Generator for Dynamic Simulations and

Abstract. The doubly fed induction generator (DFIG) is a very suitable generator type for wind turbine applications. However, its operation principles and its control are rather complex. This paper will describe the different steps for modelling and simulating the generator behaviour. A simulation example of the operation of a DFIG in a small power system is presented

Magnetic stimulation of peripheral nerves in dogs: A pilot study

A model for magnetic stimulation of the radial and sciatic nerves in dogs was evaluated. Onset-latencies and peak-to-peak amplitudes of magnetic and electrical stimulation of the sciatic nerve were compared, and the effect of the direction of the current in the magnetic coil on onset-latencies and peak-to-peak amplitude of the magnetic motor evoked potential was studied in both nerves. The results demonstrate that magnetic stimulation is a feasible method for stimulating the radial and sciatic nerves in dogs. No significant differences were observed in onset-latencies and peak-to-peak amplitudes during magnetic and electrical stimulation, indicating conformity between the techniques. Orthodromic or antidromic magnetic nerve Stimulation resulted in no significant differences. This pilot study demonstrates the potential of magnetic stimulation of nerves in dogs

Disasters and History

Disasters and History offers the first comprehensive historical overview of hazards and disasters. Drawing on a range of case studies, including the Black Death, the Lisbon earthquake of 1755 and the Fukushima disaster, the authors examine how societies dealt with shocks and hazards and their potentially disastrous outcomes. They reveal the ways in which the consequences and outcomes of these disasters varied widely not only between societies but also within the same societies according to social groups, ethnicity and gender. They also demonstrate how studying past disasters, including earthquakes, droughts, floods and epidemics, can provide a lens through which to understand the social, economic and political functioning of past societies and reveal features of a society which may otherwise remain hidden from view

Mutations in the Spliceosome Component CWC27 Cause Retinal Degeneration with or without Additional Developmental Anomalies

Pre-mRNA splicing factors play a fundamental role in regulating transcript diversity both temporally and spatially. Genetic defects in several spliceosome components have been linked to a set of non-overlapping spliceosomopathy phenotypes in humans, among which skeletal developmental defects and non-syndromic retinitis pigmentosa (RP) are frequent findings. Here we report that defects in spliceosome-associated protein CWC27 are associated with a spectrum of disease phenotypes ranging from isolated RP to severe syndromic forms. By whole-exome sequencing, recessive protein-truncating mutations in CWC27 were found in seven unrelated families that show a range of clinical phenotypes, including retinal degeneration, brachydactyly, craniofacial abnormalities, short stature, and neurological defects. Remarkably, variable expressivity of the human phenotype can be recapitulated in Cwc27 mutant mouse models, with significant embryonic lethality and severe phenotypes in the complete knockout mice while mice with a partial loss-of-function allele mimic the isolated retinal degeneration phenotype. Our study describes a retinal dystrophy-related phenotype spectrum as well as its genetic etiology and highlights the complexity of the spliceosomal gene network

A large meteoritic event over Antarctica ca. 430 ka ago inferred from chondritic spherules from the Sør Rondane Mountains

Large airbursts, the most frequent hazardous impact events, are estimated to occur orders of magnitude more frequently than crater-forming impacts. However, finding traces of these events is impeded by the difficulty of identifying them in the recent geological record. Here, we describe condensation spherules found on top of Walnumfjellet in the Sør Rondane Mountains, Antarctica. Affinities with similar spherules found in EPICA Dome C and Dome Fuji ice cores suggest that these particles were produced during a single-asteroid impact ca. 430 thousand years (ka) ago. The lack of a confirmed crater on the Antarctic ice sheet and geochemical and 18O-poor oxygen isotope signatures allow us to hypothesize that the impact particles result from a touchdown event, in which a projectile vapor jet interacts with the Antarctic ice sheet. Numerical models support a touchdown scenario. This study has implications for the identification and inventory of large cosmic events on Earth

Age- and Tumor Subtype-Specific Breast Cancer Risk Estimates for CHEK2*1100delC Carriers.

PURPOSE: CHEK2*1100delC is a well-established breast cancer risk variant that is most prevalent in European populations; however, there are limited data on risk of breast cancer by age and tumor subtype, which limits its usefulness in breast cancer risk prediction. We aimed to generate tumor subtype- and age-specific risk estimates by using data from the Breast Cancer Association Consortium, including 44,777 patients with breast cancer and 42,997 controls from 33 studies genotyped for CHEK2*1100delC. PATIENTS AND METHODS: CHEK2*1100delC genotyping was mostly done by a custom Taqman assay. Breast cancer odds ratios (ORs) for CHEK2*1100delC carriers versus noncarriers were estimated by using logistic regression and adjusted for study (categorical) and age. Main analyses included patients with invasive breast cancer from population- and hospital-based studies. RESULTS: Proportions of heterozygous CHEK2*1100delC carriers in controls, in patients with breast cancer from population- and hospital-based studies, and in patients with breast cancer from familial- and clinical genetics center-based studies were 0.5%, 1.3%, and 3.0%, respectively. The estimated OR for invasive breast cancer was 2.26 (95%CI, 1.90 to 2.69; P = 2.3 × 10(-20)). The OR was higher for estrogen receptor (ER)-positive disease (2.55 [95%CI, 2.10 to 3.10; P = 4.9 × 10(-21)]) than it was for ER-negative disease (1.32 [95%CI, 0.93 to 1.88; P = .12]; P interaction = 9.9 × 10(-4)). The OR significantly declined with attained age for breast cancer overall (P = .001) and for ER-positive tumors (P = .001). Estimated cumulative risks for development of ER-positive and ER-negative tumors by age 80 in CHEK2*1100delC carriers were 20% and 3%, respectively, compared with 9% and 2%, respectively, in the general population of the United Kingdom. CONCLUSION: These CHEK2*1100delC breast cancer risk estimates provide a basis for incorporating CHEK2*1100delC into breast cancer risk prediction models and into guidelines for intensified screening and follow-up.NIH

Impact van windenergie in het toekomstig elektriciteitsnet

This thesis investigates on various levels the technical impact of wind power on a power system. The first part develops detailed dynamic models of wind turbines or farms in software dedicated to power system simulation. These models are used to assess the impact of wind speed or power grid disturbances. The models are a suitable tool to investigate the turbine's ability to provide 'ancillary services', i.e. voltage control or other types of grid support, and to assess the impact of adapting grid connection requirements specifically for wind turbines. The second part quantifies the hourly and daily power output fluctuations of an aggregated wind park for the specific case study of the Belgian control zone, for various scenarios. Furthermore, the potential contribution to the abatement of carbon dioxide emissions by the total power generation park is assessed. The final part presents the results of a multidisciplinary study with regard to optimal offshore wind developments in the Belgian Continental Shelf, including aspects with regard to seabed properties, wind resources, turbine types and power system availability

Antioxidant Production by Xanthophyllomyces dendrorhous Under Different Stress Conditions

Antioxidants are significant contributors to the aquaculture, medical, food and cosmetic industries. Previously these molecules have been produced synthetically, but in recent years there has been a push for their natural development through plants and fungi like Xanthophyllomyces dendrorhous, a basidiomycete yeast. The red yeast X. dendrorhous naturally makes large amounts of the antioxidant astaxanthin - a carotenoid. Previous work has proven X. dendrorhous’ capability to produce carotenoids, but the most optimum growing conditions have yet to be determined. This study investigated the stressor induced metabolite production by two different X. dendrorhous strains when exposed to hydrogen peroxide, ultraviolet light, and various temperatures. Ultimately, it was determined that stress response is strain dependent, with the over producer X. dendrorhous strain always producing more astaxanthin. It is also possible that other secondary metabolites are being produced by X. dendrorhous, especially at room temperature (~23ºC). The determination of optimum growing conditions that facilitate the maximum production of metabolites by X. dendrorhous is essential for a wide range of industries whose consumers are more responsive to the natural production of antioxidants because bio-based products are more sustainable and environmentally friendly