Exact Moment Simulation using Random Orthogonal Matrices

This paper introduces a method for simulating multivariate samples that have exact means, covariances, skewness and kurtosis. A new class of rectangular orthogonal matrices is fundamental to the methodology, and these ``L-matrices'' can be deterministic, parametric or data specific in nature. The target moments determine an L-matrix, then infinitely many random samples with the same exact moments may be generated by multiplying the L-matrix by arbitrary random orthogonal matrices. The methodology is thus termed ``ROM simulation''. We discuss certain classes of random orthogonal matrices and show how each class produces samples with different characteristics. ROM simulation has applications to many problems that are resolved using standard Monte Carlo methods. But since no parametric assumptions are required there is no sampling error caused by the discrete approximation of a continuous distribution, which is a major source of error in standard Monte Carlo simulations. For illustration, we apply ROM simulation to determine the value-at-risk of a stock portfolio.simulation, L-matrices, multivariate moments, value-at-risk

PARP inhibitors in ovarian cancer

BACKGROUND: Slow progress in improving the outcome of ovarian cancer with chemotherapy over the last decade has stimulated research into molecularly targeted therapy. Poly(ADP-ribose) polymerase (PARP) inhibitors target DNA repair and are specifically active in cells that have impaired repair of DNA by the homologous recombination (HR) pathway. Cells with mutated BRCA function have HR deficiency (HRD), which is also present in a significant proportion of non-BRCA-mutated ovarian cancer. DESIGN: In the last decade, olaparib, the first and most-investigated oral PARP inhibitor, has undergone phase I-III trials as a single agent, in comparison with and in addition to chemotherapy, and as a maintenance therapy following chemotherapy. RESULTS: The greatest benefit to-date has been in the maintenance setting, prolonging the progression-free survival of high-grade serous ovarian cancer with a BRCA1/2 mutation. In this group of patients, olaparib has received approval as maintenance following chemotherapy from the EMA, and accelerated approval as a single agent in women who have had three or more lines of therapy. Olaparib can be given for a prolonged period with few significant side-effects in most patients. Similar trials with other PARP inhibitors (rucaparib, niraparib and veliparib) are in progress and include non-BRCA-mutated ovarian cancer. Second-generation studies are exploring the combination of PARP inhibitors with anti-angiogenic drugs. CONCLUSIONS: PARP inhibitors represent a step change in the management of ovarian cancer. BRCA mutations are the first genotypic predictive markers in ovarian cancer and can be used to select patients who will most likely benefit from PARP inhibitors. BRCA testing is now becoming a routine part of the evaluation of women with ovarian cancer, and tests for HRD are being used to evaluate PARP inhibitors in an extended population of non-BRCA-mutated ovarian cancer

Design, Fabrication, and Characterisation of Three-Dimensional Photonic Quasicrystals

Photonic structures manipulate the propagation of light by scattering and interference effects. We fabricate and optically characterise high-quality three-dimensional photonic quasicrystals operating at infrared frequencies. They mimic a diffusive behaviour usually known from disordered systems, due to multiple scattering of light. We study icosahedral quasicrystals, known from electronic systems, in both experiment and theory, as well as rhombicuboctahedral ones, a novel class introduced by us

Relations of Burnout to Elementary School Teachers, Special Education Beliefs, and Referral Expectations

The Maslach Burnout Inventory (MBI; Maslach, Jackson, & Schwab, 1996), a teacher survey of expectations and preferences concerning case study evaluation referral, and demographic questions were completed by regular education elementary school teachers (n=88) in a midwestern city suburb. Results suggested that symptoms of burnout were not evident among this sample of professionals according to Maslach et al. (1996) criteria. Spearman Rho correlations between the MBI subscales and expectations or preferences to have students referred, tested and placed into special education services were not significant. Significant correlations were replicated among the subscales of the Maslach Burnout Inventory. Results suggested that level of burnout is not related to different beliefs or expectations of referral, testing and placement of students in special education. However, low return rate and the fact that burnout was not evident with this particular sample, suggest further research in this area is needed to determine if burnout symptoms affect expectations for testing and placement of difficult to teach students

Increasing Universities\u27 Tuition Fee Revenues from International Undergraduate Students

Universities are losing expected tuition revenues due to attrition of international undergraduate students. The purpose of this multiple case study was to explore strategies that university leaders use to increase tuition fee revenues from international undergraduate students. The participants in this study were 3 former leaders of the European division of Laureate International Universities, a global university group with university locations in the United Kingdom, Germany, France, Spain, Portugal, Italy, and Cyprus. The conceptual framework of this study was institutional theory as part of the change management of universities. Data collection included semistructured interviews of 3 former leaders of the European division of Laureate International Universities and a review of background and demographic information. Data analysis revealed 5 themes: business strategies, leadership, politics and governmental practice, social mobility, and attrition. These themes aligned with the institutional theory and change management conceptual framework. Recommendations for action include further research in the application of university business models to adopt or enhance a process for retaining international undergraduate students. The results of this study may contribute to social change by indicating how universities can be financially sustainable by providing international students access to an international education. University leaders may implement some of my recommendations and suggested strategies to avoid losing expected tuition revenues due to attrition of international undergraduate students. International undergraduate students may enroll in better prepared universities and therefore, succeed in completing and graduating from their selected studies

The status of poly(adenosine diphosphate-ribose) polymerase (PARP) inhibitors in ovarian cancer, part 2: extending the scope beyond olaparib and BRCA1/2 mutations

Poly(adenosine diphosphate-ribose) polymerase (PARP) inhibitors have shown clinical activity in epithelial ovarian cancer, leading both the US Food and Drug Administration (FDA) and the European Medicines Agency to approve olaparib for tumors characterized by BRCA1 and BRCA2 mutations. However, it is becoming increasingly evident that tumors that share molecular features with BRCA-mutant tumors-a concept known as BRCAness-also may exhibit defective homologous recombination DNA repair, and therefore will respond to PARP inhibition. A number of strategies have been proposed to identify BRCAness, including identifying defects in other genes that modulate homologous recombination and characterizing the mutational and transcriptional signatures of BRCAness. In addition to olaparib, a number of other PARP inhibitors are in clinical development. This article reviews the development of PARP inhibitors other than olaparib, and discusses the evidence for PARP inhibitors beyond BRCA1/2-mutant ovarian cancer

Verbreitung der Direktsaat in der Schweiz

Direktsaat ist eine wirksame Erosionsschutzmassnahme, die diverse ökologische und ökonomische Vorteile aufweist. Sie gewann in der Schweiz in den letzten Jahren zunehmend an Bedeutung: Seit Mitte der 1980er hat die direkt gesäte Fläche von wenigen Hektaren auf rund 12'000 ha im Jahre 2006 zugenommen. Gemessen am gesamten Ackerland ist diese Fläche aber nach wie vor gering (3 %). Regional kann die Direktsaat jedoch beachtliche Anteile aufweisen. Die in diesem Artikel vorgestellten Karten geben einen nationalen Überblick über die räumliche Verbreitung der direkt gesäten Fläche im Jahr 2006. Als Datengrundlage diente eine im Winter 2006 / 07 durchgeführte Befragung von Landwirten und Lohnunternehmern. Die Karten zeigen sehr heterogene Muster, machen aber auch verschiedene Schwerpunktregionen sichtbar. Die Interpretation dieser Muster veranschaulicht, dass die Verbreitung der Direktsaat an eine Vielzahl von Faktoren gebunden ist und nicht nur anhand naturräumlicher Gegebenheiten erklärt werden kann. Kantonale Förderprogramme spielen dabei eine ebenso wichtige Rolle wie das persönliche Engagement der beteiligten Experten und Lohnunternehmer, bestehende landwirtschaftliche Netzwerke sowie die Lebenswelten der Landwirte