Process development on the monolithic fabrication of an ultra-compact 4×4 optical switch matrix on InP/InGaAsP material

We have fabricated an ultra-compact 4×4 optical matrix on InP/InGaAsP material. 1×4 MMI couplers and TIR mirrors are employed to produce a compact 1×2 mm2 device. A CH4/H2/O2 RIE dry etch process has been used to realize two-level dry etching: deep-etch for both the MMI couplers and the mirrors and shallow-etch for the rest of the routing waveguides. It was found that a metal/dielectric bilayer mask is essential for multi-dry-etch processes and high profile verticality. We have found a Ti intermediate mask for the deep-etch process which is removable by SF6 dry-etch before the following shallow process. Dry-etch removal of the intermediate mask is necessary to protect the deep-etched mirror sidewall.

Genes involved in the metabolism of fatty acids and risk for Crohn's disease in children: a candidate gene study

Contexte - La prévalence de la maladie de Crohn (MC), une maladie inflammatoire chronique du tube digestif, chez les enfants canadiens se situe parmi les plus élevées au monde. Les interactions entre les réponses immunes innées et acquises aux microbes de l'hôte pourraient être à la base de la transition de l’inflammation physiologique à une inflammation pathologique. Le leucotriène B4 (LTB4) est un modulateur clé de l'inflammation et a été associé à la MC. Nous avons postulé que les principaux gènes impliqués dans la voie métabolique du LTB4 pourrait conférer une susceptibilité accrue à l'apparition précoce de la MC. Dans cette étude, nous avons exploré les associations potentielles entre les variantes de l'ADN des gènes ALOX5 et CYP4F2 et la survenue précoce de la MC. Nous avons également examiné si les gènes sélectionnés montraient des effets parent-d'origine, influençaient les phénotypes cliniques de la MC et s'il existait des interactions gène-gène qui modifieraient la susceptibilité à développer la MC chez l’enfant. Méthodes – Dans le cadre d’une étude de cas-parents et de cas-témoins, des cas confirmés, leurs parents et des contrôles ont été recrutés à partir de trois cliniques de gastro-entérologie à travers le Canada. Les associations entre les polymorphismes de remplacement d'un nucléotide simple (SNP) dans les gènes CYP4F2 et ALOX5 ont été examinées. Les associations allélique et génotypiques ont été examinées à partir d’une analyse du génotype conditionnel à la parenté (CPG) pour le résultats cas-parents et à l’aide de table de contingence et de régression logistique pour les données de cas-contrôles. Les interactions gène-gène ont été explorées à l'aide de méthodes de réduction multi-factorielles de dimensionnalité (MDR). Résultats – L’étude de cas-parents a été menée sur 160 trios. L’analyse CPG pour 14 tag-SNP (10 dans la CYP4F2 et 4 dans le gène ALOX5) a révélé la présence d’associations alléliques ou génotypique significatives entre 3 tag-SNP dans le gène CYP4F2 (rs1272, p = 0,04, rs3093158, p = 0.00003, et rs3093145, p = 0,02). Aucune association avec les SNPs de ALOX5 n’a pu être démontrée. L’analyse de l’haplotype de CYP4F2 a montré d'importantes associations avec la MC (test omnibus p = 0,035). Deux haplotypes (GAGTTCGTAA, p = 0,05; GGCCTCGTCG, p = 0,001) montraient des signes d'association avec la MC. Aucun effet parent-d'origine n’a été observé. Les tentatives de réplication pour trois SNPs du gene CYP4F2 dans l'étude cas-témoins comportant 225 cas de MC et 330 contrôles suggèrent l’association dans un de ceux-ci (rs3093158, valeur non-corrigée de p du test unilatéral = 0,03 ; valeur corrigée de p = 0.09). La combinaison des ces deux études a révélé des interactions significatives entre les gènes CYP4F2, ALOX et NOD2. Nous n’avons pu mettre en évidence aucune interaction gène-sexe, de même qu’aucun gène associé aux phénotypes cliniques de la MC n’a pu être identifié. Conclusions - Notre étude suggère que la CYP4F2, un membre clé de la voie métabolique LTB4 est un gène candidat potentiel pour MC. Nous avons également pu mettre en évidence que les interactions entre les gènes de l'immunité adaptative (CYP4F2 et ALOX5) et les gènes de l'immunité innée (NOD2) modifient les risques de MC chez les enfants. D'autres études sur des cohortes plus importantes sont nécessaires pour confirmer ces conclusions.

Descomposición de la estructura a términos de las tasas de interés de los bonos soberanos de Estados Unidos y Colombia

En el presente documento se descompone la estructura a términos de las tasas de interés de los bonos soberanos de EE.UU. y Colombia. Se utiliza un modelo afín de cuatro factores, donde el primero de ellos corresponde a un factor de pronóstico de los retornos y, los demás, a los tres primeros componentes principales de la matriz de varianza-covarianza de las tasas de interés. Para la descomposición de las tasas de interés de Colombia se utiliza el factor de pronóstico de EE.UU. para capturar efectos de spillovers. Se logra concluir que las tasas en EE.UU. no tienen un efecto sobre el nivel de tasas en Colombia pero sí influyen en los excesos de retorno esperado de los bonos y también existen efectos sobre los factores locales, aunque el factor determinante de la dinámica de las tasas locales es el “nivel”. De la descomposición se obtienen las expectativas de la tasa corta y la prima por vencimiento. En ese sentido, se observa que el valor de la prima por vencimiento y su volatilidad incrementa con el vencimiento y que este valor ha venido disminuyendo en el tiempo.

Estructura a Plazo Colombia: Modelo Afín de tres factores

La estimación e interpretación de la estructura a plazo de la tasas de interés es de gran relevancia porque permite realizar pronósticos, es fundamental para la toma de decisiones de política monetaria y fiscal, es esencial en la administración de riesgos y es insumo para la valoración de diferentes activos financieros. Por estas razones, es necesario entender que puede provocar un movimiento en la estructura a plazo. En este trabajo se estiman un modelo afín exponencial de tres factores aplicado a los rendimientos de los títulos en pesos de deuda pública colombianos. Los factores estimados son la tasa corta, la media de largo plazo de la tasa corta y la volatilidad de la tasa corta. La estimación se realiza para el periodo enero 2010 a mayo de 2015 y se realiza un análisis de correlaciones entre los tres factores. Posterior a esto, con los factores estimados se realiza una regresión para identificar la importancia que tiene cada uno de estos en el comportamiento de las tasas de los títulos de deuda pública colombiana para diferentes plazos al vencimiento. Finalmente, se estima la estructura a plazo de las tasas de interés para Colombia y se identifica la relación de los factores estimados con los encontrados por Litterman y Scheinkman [1991] correspondientes al nivel, pendiente y curvatura.

Vegetation dynamics in abandoned crop fields on a Mediterranean island: Development of succession model and estimation of disturbance thresholds

This case study on the Sifnos island, Greece, assesses the main factors controlling vegetation succession following crop abandonment and describes the vegetation dynamics of maquis and phrygana formations in relation to alternative theories of secondary succession. Field survey data were collected and analysed at community as well as species level. The results show that vegetation succession on abandoned crop fields is determined by the combined effects of grazing intensity, soil and geological characteristics and time. The analysis determines the quantitative grazing thresholds that modify the successional pathway. Light grazing leads to dominance by maquis vegetation while overgrazing leads to phryganic vegetation. The proposed model shows that vegetation succession following crop abandonment is a complex multi-factor process where the final or the stable stage of the process is not predefined but depends on the factors affecting succession. An example of the use of succession models and disturbance thresholds as a policy assessment tool is presented by evaluating the likely vegetation impacts of the recent reform of the Common Agricultural Policy on Sifnos island over a 20-30-year time horizon. (c) 2006 Elsevier B.V. All rights reserved.

Corporate social performance and stock returns: UK evidence from disaggregate measures

This study examines the relation between corporate social performance and stock returns in the UK. We closely evaluate the interactions between social and financial performance with a set of disaggregated social performance indicators for environment, employment, and community activities instead of using an aggregate measure. While scores on a composite social performance indicator are negatively related to stock returns, we find the poor financial reward offered by such firms is attributable to their good social performance on the environment and, to a lesser extent, the community aspects. Considerable abnormal returns are available from holding a portfolio of the socially least desirable stocks. These relationships between social and financial performance can be rationalized by multi-factor models for explaining the cross-sectional variation in returns, but not by industry effects.

The underlying return generating factors for REIT returns: an application of independent component analysis

Multi-factor approaches to analysis of real estate returns have, since the pioneering work of Chan, Hendershott and Sanders (1990), emphasised a macro-variables approach in preference to the latent factor approach that formed the original basis of the arbitrage pricing theory. With increasing use of high frequency data and trading strategies and with a growing emphasis on the risks of extreme events, the macro-variable procedure has some deficiencies. This paper explores a third way, with the use of an alternative to the standard principal components approach – independent components analysis (ICA). ICA seeks higher moment independence and maximises in relation to a chosen risk parameter. We apply an ICA based on kurtosis maximisation to weekly US REIT data using a kurtosis maximising algorithm. The results show that ICA is successful in capturing the kurtosis characteristics of REIT returns, offering possibilities for the development of risk management strategies that are sensitive to extreme events and tail distributions.

Participatory scenarios as a tool to link science and policy on food security under climate change in East Africa

How effective are multi-stakeholder scenarios building processes to bring diverse actors together and create a policy-making tool to support sustainable development and promote food security in the developing world under climate change? The effectiveness of a participatory scenario development process highlights the importance of ‘boundary work’ that links actors and organizations involved in generating knowledge on the one hand, and practitioners and policymakers who take actions based on that knowledge on the other. This study reports on the application of criteria for effective boundary work to a multi-stakeholder scenarios process in East Africa that brought together a range of regional agriculture and food systems actors. This analysis has enabled us to evaluate the extent to which these scenarios were seen by the different actors as credible, legitimate and salient, and thus more likely to be useful. The analysis has shown gaps and opportunities for improvement on these criteria, such as the quantification of scenarios, attention to translating and communicating the results through various channels and new approaches to enable a more inclusive and diverse group of participants. We conclude that applying boundary work criteria to multi-stakeholder scenarios processes can do much to increase the likelihood of developing sustainable development and food security policies that are more appropriate.

The financial and environmental performance of firms exposed to the EU Emissions Trading Scheme

This thesis is an empirical-based study of the European Union’s Emissions Trading Scheme (EU ETS) and its implications in terms of corporate environmental and financial performance. The novelty of this study includes the extended scope of the data coverage, as most previous studies have examined only the power sector. The use of verified emissions data of ETS-regulated firms as the environmental compliance measure and as the potential differentiating criteria that concern the valuation of EU ETS-exposed firms in the stock market is also an original aspect of this study. The study begins in Chapter 2 by introducing the background information on the emission trading system (ETS), which focuses on (i) the adoption of ETS as an environmental management instrument and (ii) the adoption of ETS by the European Union as one of its central climate policies. Chapter 3 surveys four databases that provide carbon emissions data in order to determine the most suitable source of the data to be used in the later empirical chapters. The first empirical chapter, which is also Chapter 4 of this thesis, investigates the determinants of the emissions compliance performance of the EU ETS-exposed firms through constructing the best possible performance ratio from verified emissions data and self-configuring models for a panel regression analysis. Chapter 5 examines the impacts on the EU ETS-exposed firms in terms of their equity valuation with customised portfolios and multi-factor market models. The research design takes into account the emissions allowance (EUA) price as an additional factor, as it has the most direct association with the EU ETS to control for the exposure. The final empirical Chapter 6 takes the investigation one step further, by specifically testing the degree of ETS exposure facing different sectors with sector-based portfolios and an extended multi-factor market model. The findings from the emissions performance ratio analysis show that the business model of firms significantly influences emissions compliance, as the capital intensity has a positive association with the increasing emissions-to-emissions cap ratio. Furthermore, different sectors show different degrees of sensitivity towards the determining factors. The production factor influences the performance ratio of the Utilities sector, but not the Energy or Materials sectors. The results show that the capital intensity has a more profound influence on the utilities sector than on the materials sector. With regard to the financial performance impact, ETS-exposed firms as aggregate portfolios experienced a substantial underperformance during the 2001–2004 period, but not in the operating period of 2005–2011. The results of the sector-based portfolios show again the differentiating effect of the EU ETS on sectors, as one sector is priced indifferently against its benchmark, three sectors see a constant underperformance, and three sectors have altered outcomes.

Objective grading of fabric pilling with wavelet texture analysis

A new objective fabric pilling grading method based on wavelet texture analysis was developed. The new method created a complex texture feature vector based on the wavelet detail coefficients from all decomposition levels and horizontal, vertical and diagonal orientations, permitting a much richer and more complete representation of pilling texture in the image to be used as a basis for classification. Standard multi-factor classification techniques of principal components analysis and discriminant analysis were then used to classify the pilling samples into five pilling degrees. The preliminary investigation of the method was performed using standard pilling image sets of knitted, woven and non-woven fabrics. The results showed that this method could successfully evaluate the pilling intensity of knitted, woven and non-woven fabrics by selecting the suitable wavelet and associated analysis scale.

The complexity of social practice : understanding inertia and change in maternity care organizations

Beyond the limited efficiency and economy goals of neoliberal health policy lies the promise of genuine health services reform. In maternity care in particular, recent policy developments have sought to make the management of birth more ‘women-centred and family-friendly’. Interprofessional collaboration and greater consumer participation in policy and decision-making are key means to achieve this goal, but changing the entrenched system of medicalised birth remains difficult. Recent social contestation of maternity care has destabilised but not eradicated pervasive medical hegemony. Further reform requires analysis both of institutionalised patterns of power, and attention to the fluidity and situated knowledge shaping organisational and professional practices. Accordingly, this paper outlines a framework with which to explore the multi-layered social processes involved in implementing organisational and cultural change in maternity care. Analysis of social interventions in health systems, we suggest, can be advanced by drawing on strands from critical organization studies, complexity and critical discourse theories and social practice approaches.

An investigation on asset allocation and performance measurement for unit trust funds in Malaysia using multifactor model : a post crisis period analysis

This study examines the pattern of asset allocation and the performance of unit trust in Malaysia over the post crisis period by using risk-adjusted performance measures and multi-factor model from the year 2000 to 2004. Evidence from the statistics suggests that an active asset allocation strategy had been observed among Malaysian fund managers during the post Asian financial crisis. It is also suggested that investment allocation in equity remained a dominant vehicle for investment and asset allocation. Findings from multifactor model suggest that all funds of different objectives registered positive alphas except for income funds, with growth funds being among the top. While balanced funds registered highest diversification effectively, diversifying away about 70%-80% of unsystematic risk, the momentum factor is not among the important elements to explain unit trust performance in Malaysia.

Unmet needs and depression among carers of people newly diagnosed with cancer

AIMS: The aims of this analysis were to examine levels of unmet needs and depression among carers of people newly diagnosed with cancer and to identify groups who may be at higher risk, by examining relationships with demographic characteristics. METHODS: One hundred and fifty dyads of people newly diagnosed with cancer and their carers, aged 18years and older, were recruited from four Australian hospitals. People with cancer receiving adjuvant cancer treatment with curative intent, were eligible to participate. Carers completed the Supportive Care Needs Survey-Partners & Caregivers (SCNS-P&C45), and both carers and patients completed the Centre of Epidemiologic-Depression Scale (CES-D). RESULTS: Overall, 57% of carers reported at least one, 37% at least three, 31% at least five, and 15% at least 10 unmet needs; the most commonly endorsed unmet needs were in the domains of information and health care service needs. Thirty percent of carers and 36% of patients were at risk of clinical depression. A weak to moderate positive relationship was observed between unmet needs and carer depression (r=0.30, p<0.001). Carer levels of unmet needs were significantly associated with carer age, hospital type, treatment type, cancer type, living situation, relationship status (in both uni- and multi-factor analysis); person with cancer age and carer level of education (in unifactor analysis only); but not with carer gender or patient gender (in both uni- and multi-factor analyses). CONCLUSION: Findings highlight the importance of developing tailored programmes to systematically assist carers who are supporting patients through the early stages of cancer treatment.

Nitretação a plasma em furos não passantes

Este trabalho tem por objetivo avaliar a influência dos parâmetros pressão, freqüência e fator de trabalho, bem como a interação destes fatores, na capacidade de gerar plasma estável e com propriedades nitretantes no interior de furos não passantes de pequeno diâmetro. Para atingir estes objetivos foram realizados experimentos utilizando um reator equipado com fonte de potência pulsada de 2 KW, mistura gasosa composta de 76% de Nitrogênio e 24% de Hidrogênio, amostras de aço ABNT 1045 normalizadas. As nitretações foram realizadas pelo período de uma hora a temperatura de 500 0C. Foram empregadas freqüências de 100, 1000 e 5000 Hz, fatores de trabalho de 0,5 (50%), 0,75 (75%), 1 (100%), as pressões utilizadas foram de 2, 3 e 4 Torr e furos não passantes de φ3 x 40 mm, φ4 x 60 mm, φ5 x 75 mm. Para determinar a significância de cada parâmetro e de suas interações foi utilizado o modelo estatístico Multi-Factor Anova, com projeto fatorial cruzado a 3 fatores e 3 níveis para cada fator. Com o uso do programa Statgraphics foram geradas as equações que mais se ajustaram ao modelo. Estas equações determinam a máxima profundidade de geração de plasma nitretante no interior dos furos de pequeno diâmetro para as condições de tratamento expostas acima.