Direct grating writing: single-step Bragg grating and waveguide fabrication for telecommunications and sensing applications

Direct Grating Writing (DGW) has been developed over the past decade as a means of rapidly prototyping waveguides with integrated Bragg grating structures in silica-on-silicon substrates [1]. The technique allows complicated waveguide structures and Bragg grating arrays to be fabricated and characterised in house

FUSE Measurements of Far Ultraviolet Extinction. I. Galactic Sight Lines

We present extinction curves that include data down to far ultraviolet wavelengths (FUV; 1050 - 1200 A) for nine Galactic sight lines. The FUV extinction was measured using data from the Far Ultraviolet Spectroscopic Explorer. The sight lines were chosen for their unusual extinction properties in the infrared through the ultraviolet; that they probe a wide range of dust environments is evidenced by the large spread in their measured ratios of total-to-selective extinction, R_V = 2.43 - 3.81. We find that extrapolation of the Fitzpatrick & Massa relationship from the ultraviolet appears to be a good predictor of the FUV extinction behavior. We find that predictions of the FUV extinction based upon the Cardelli, Clayton & Mathis (CCM) dependence on R_V give mixed results. For the seven extinction curves well represented by CCM in the infrared through ultraviolet, the FUV extinction is well predicted in three sight lines, over-predicted in two sight lines, and under-predicted in 2 sight lines. A Maximum Entropy Method analysis using a simple three component grain model shows that seven of the nine sight lines in the study require a larger fraction of grain materials to be in dust when FUV extinction is included in the models. Most of the added grain material is in the form of small (radii < 200 A) grains.Comment: Accepted for publication in the Astrophysical Journal. 31 pages with 7 figure

The Role of Polycyclic Aromatic Hydrocarbons in Ultraviolet Extinction. I. Probing small molecular PAHs

We have obtained new STIS/HST spectra to search for structure in the ultraviolet interstellar extinction curve, with particular emphasis on a search for absorption features produced by polycyclic aromatic hydrocarbons (PAHs). The presence of these molecules in the interstellar medium has been postulated to explain the infrared emission features seen in the 3-13 $\mu$m spectra of numerous sources. UV spectra are uniquely capable of identifying specific PAH molecules. We obtained high S/N UV spectra of stars which are significantly more reddened than those observed in previous studies. These data put limits on the role of small (30-50 carbon atoms) PAHs in UV extinction and call for further observations to probe the role of larger PAHs. PAHs are of importance because of their ubiquity and high abundance inferred from the infrared data and also because they may link the molecular and dust phases of the interstellar medium. A presence or absence of ultraviolet absorption bands due to PAHs could be a definitive test of this hypothesis. We should be able to detect a 20 \AA wide feature down to a 3$\sigma$ limit of $\sim$0.02 A$_V$. No such absorption features are seen other than the well-known 2175 \AA bump.Comment: 16 pages, 3 figure, ApJ in pres

Positivity of the English language

Over the last million years, human language has emerged and evolved as a fundamental instrument of social communication and semiotic representation. People use language in part to convey emotional information, leading to the central and contingent questions: (1) What is the emotional spectrum of natural language? and (2) Are natural languages neutrally, positively, or negatively biased? Here, we report that the human-perceived positivity of over 10,000 of the most frequently used English words exhibits a clear positive bias. More deeply, we characterize and quantify distributions of word positivity for four large and distinct corpora, demonstrating that their form is broadly invariant with respect to frequency of word use.Comment: Manuscript: 9 pages, 3 tables, 5 figures; Supplementary Information: 12 pages, 3 tables, 8 figure

Evaluating social science and humanities knowledge production: An exploratory analysis of dynamics in science systems

Knowledge is gaining increasing importance in modern-day society as a factor of production and, ultimately, growth. This article explores the dynamics in university knowledge production and its effect on the state of university-industry-policy exchange in the Netherlands. Science systems are said to be in transformation. The university has evolved from performing conventional research and educational functions to serving as an innovation-promoting knowledge hub; dynamics that have received mixed reactions. The social sciences and humanities (SSH) take a special position, insofar as their focus seems primarily to be placed on conventional research and educational functions, and not directly on (commercial) valorization. Societal changes are, however, pressing for a reconsideration of the role of SSH. In our article, we distinguish between three important new movements that seem to be affecting SSH. It is believed that these movements, which are already having an impact today, will considerably influence SSH in the future. These developments are further differentiation, synthesis between the various subdisciplines of SSH and the natural sciences, and shifts in paradigms. The aims of this article are twofold: (1) to assess what is believed to be the most likely development of SSH by means of discovering relevant subsets of factors influencing university knowledge production; and (2) to discover whether the knowledge production factors show characteristics of a general development similar to the "Mode 2" concept. A systematic qualitative database was created by means of 22 semi-structured personal interviews with key representatives from business, university and the policy sector. Our explanatory framework employs an artificial intelligence method, i.e. rough set analysis. On the basis of these results, we find that a small minority of the respondents prefers a closer relationship of SSH to society, government and industry, and other institutional centers of authority, whilst interdisciplinarity in particular is regarded as having an overall positive influence on the future of SSH in the Netherlands. Consequently, the idea of a clear distinction between Mode 1 and Mode 2 knowledge production, i.e. traditional knowledge and knowledge carried out in the context of application, is not supported by our data. © 2009 Interdisciplinary Centre for Comparative Research in the Social Sciences and ICCR Foundation

The Global Flood Partnership Conference 2017 - From hazards to impacts

From 27 – 29 June 2017, the 2017 Global Flood Partnership Conference was held at the University of Alabama, U.S.A. More than 90 participants attended the conference coming from 11 different countries in 5 continents. They represented 56 institutions including international organisations, the private sector, national authorities, universities, governmental research agencies and non-profit organisations. Each year, floods cause devastating losses and damage across the world. Growing populations in ill-planned flood-prone coastal and riverine areas are increasingly exposed to more extreme rainfall events. With more population and economic assets at risk, governments, banks, international development and relief agencies, and private firms are investing in flood reduction measures. However, in many countries, the flood risk is not managed optimally because of a lack of scientific data and methods or a communication gap between science and risk managers. The Global Flood Partnership was launched in 2014 and is a cooperation framework between scientific organisations and flood disaster managers worldwide to develop flood observational and modeling infrastructure, leveraging on existing initiatives for better predicting and managing flood disaster impacts and flood risk globally. The conference theme was “From hazards to impacts” and participants had the opportunity to showcase their latest relevant research and activities. As usual, the advances and success stories of the Partnership were reviewed and the next steps to further strengthen the GFP were discussed. As in past meetings, participants had numerous opportunities to present their work, exchange ideas, and turn it into a lively and successful meeting. This included a "Marketplace of Ideas" session, "Ignite" talks, Problem-solving session, workshops, poster pitch session and breakout groups.JRC.E.1-Disaster Risk Managemen

A search for charged massive long-lived particles

We report on a search for charged massive long-lived particles (CMLLPs), based on 5.2 fb$^{-1}$ of integrated luminosity collected with the D0 detector at the Fermilab Tevatron $p\bar{p}$ collider. We search for events in which one or more particles are reconstructed as muons but have speed and ionization energy loss $(dE/dx)$ inconsistent with muons produced in beam collisions. CMLLPs are predicted in several theories of physics beyond the standard model. We exclude pair-produced long-lived gaugino-like charginos below 267 GeV and higgsino-like charginos below 217 GeV at 95% C.L., as well as long-lived scalar top quarks with mass below 285 GeV.Comment: submitted to Phys. Rev. Letter

For money or service? a cross-sectional survey of preference for financial versus non-financial rural practice characteristics among ghanaian medical students

Abstract Background Health worker shortage and maldistribution are among the biggest threats to health systems in Africa. New medical graduates are prime targets for recruitment to deprived rural areas. However, little research has been done to determine the influence of workers' background and future plans on their preference for rural practice incentives and characteristics. The purpose of this study was to identify determinants of preference for rural job characteristics among fourth year medical students in Ghana. Methods We asked fourth-year Ghanaian medical students to rank the importance of rural practice attributes including salary, infrastructure, management style, and contract length in considering future jobs. We used bivariate and multivariate ordinal logistic regression to estimate the association between attribute valuation and students' socio-demographic background, educational experience, and future career plans. Results Of 310 eligible fourth year medical students, complete data was available for 302 students (97%). Students considering emigration ranked salary as more important than students not considering emigration, while students with rural living experience ranked salary as less important than those with no rural experience. Students willing to work in a rural area ranked infrastructure as more important than students who were unwilling, while female students ranked infrastructure as less important than male students. Students who were willing to work in a rural area ranked management style as a more important rural practice attribute than those who were unwilling to work in a rural area. Students studying in Kumasi ranked contract length as more important than those in Accra, while international students ranked contract length as less important than Ghanaian students. Conclusions Interventions to improve rural practice conditions are likely to be more persuasive than salary incentives to Ghanaian medical students who are willing to work in rural environments a priori. Policy experiments should test the impact of these interventions on actual uptake by students upon graduation.http://deepblue.lib.umich.edu/bitstream/2027.42/112499/1/12913_2011_Article_1837.pd