5,055 research outputs found
Higgs bundles over elliptic curves
In this paper we study -Higgs bundles over an elliptic curve when the
structure group is a classical complex reductive Lie group. Modifying the
notion of family, we define a new moduli problem for the classification of
semistable -Higgs bundles of a given topological type over an elliptic curve
and we give an explicit description of the associated moduli space as a finite
quotient of a product of copies of the cotangent bundle of the elliptic curve.
We construct a bijective morphism from this new moduli space to the usual
moduli space of semistable -Higgs bundles, proving that the former is the
normalization of the latter. We also obtain an explicit description of the
Hitchin fibration for our (new) moduli space of -Higgs bundles and we study
the generic and non-generic fibres
Prevention and Health: from complex life course to simple solutions
__Abstract__
Rede, uitgesproken ter gelegenheid van
het aanvaarden van het ambt
van hoogleraar Epidemiologische basis
van preventieve geneeskunde
i.h.b. cardiovasculaire aandoeningen
aan het Erasmus MC, faculteit van
de Erasmus Universiteit Rotterdam
op 3 mei 201
Cardiovascular Disease Prfevention: from meta-analyses to life expectancies
Cardiovascular Disease (CVD) includes dysfunctional conditions of the heart and of
the blood vessel system (arteries, veins, and capillaries) that among other functions
supply oxygen to all body tissues and organs, including vital life-sustaining areas
like the brain and the heart itself. Coronary heart disease and stroke are the principal
components of CVD. Cardiovascular disease is the leading cause of mortality and
morbidity worldwide. It is on the rise and has become a true pandemic that respect
no borders.
This thesis presents studies on different areas of the epidemiology of CVD
and its prevention. Three specific research questions were investigated:
1.
What is the effect of risk factors for cardiovascular disease such as physical
inactivity and hypertension, in terms of life expectancy and years lived with
and without cardiovascular disease?
2.
What is the cost-effectiveness of various strategies for cardiovascu
First report of Leptosphaeria biglobosa ‘brassicae’ as causal agent of phoma leaf spot in Brassica napus (Canola) in Argentina
Canola(Brassicanapus L.) is the second largest oilseed crop in the worldproviding 13% of the world´s oil supply. This crop has been grown in Argentinasince the 1930s, and the area devoted to its cultivation varies every year,reaching a maximum of 95000 Ha in the 2012/2013 growing season. Because of theoccurrence of optimal weather conditions and soils with high fertility, theaverage yield in this region is about 2000 kg/Ha. Phoma leaf spot and Phomastem canker are considered the most important and devastating diseases in Brassica napus andother Brassicaespecies [1]. In both cases, the causal agent is a complexof two closely related fungal species, Leptosphaeria maculans and L. biglobosa. In Argentina,the presence of L. maculans incanola plants was reported for the first time in 2004 [2], but the existence ofL.biglobosa has not been recorded so far. During the 2015/2016season, we collected several samples with typical Phoma leaf spot symptoms fromcanola plants growing in fields from the north and northeastern regions of the Buenos Aires province.The necrotic lesions were circular to irregularly oval, 8 to 15 mm in diameter,pale brown in the center, grayish green at the margin and characterized withthe presence of pycnidia. Several leaf pieces with lesions were rinsed twicewith deionized sterile water and placed in a humid chamber (90 mm diameterPetri dish with a layer of filter paper soaked in deionized sterile water) during2-3 days to induce the pycnidia to exude cirri of conidia. After this period,one cirrus per sample was transferred onto PDA plates supplemented withantibiotics (15 mg/L streptomycin, 15 mg/L gentamicin and 12 mg/L tetracycline)using an inoculation needle under stereoscopic microscope. Thus, severalisolates were obtained, some of them showing rapid mycelial growth rate andpigment production on PDA medium, as showed by the isolate Tapidor of L. biglobosa thatwe used as control (kindly provided by Professor Bruce Fitt, University ofHertfordshire-UK). In order to confirm the identity of these isolates, a PCRassay using genomic DNA as template was performed to distinguish L. maculans from L. biglobosa withthe species-specific primers LmacR, LmacF,and LbigF ina three-primers strategy described by Gaetan (2005)[3]. These reactions gave a444-bp amplicon as expected for L. biglobosa ´brassicae´.In addition, these results were confirmed by sequencing the nuclear ribosomalinternal transcribed spacer (ITS) region, which showed a 99% of identity withthe sequence of L. biglobosa ´brassicae´at the GenBank database (FO905468). L. biglobosa isolateswere then tested for pathogenicity on the canola cultivars Westar and Bioaureo2286 (Nuseed). With this purpose, cotyledons of 10-day-old seedlings werepricked with a needle, and each wound inoculated with 10 μl ofa conidial suspension (107 42conidia/ml). Sterilized distilled water was used as control. Developing primaryleaves were removed every 2-3 days in order to ensure that cotyledons continueto expand. Fourteen days after inoculation, irregular and brown necroticlesions were visible at the site of inoculation. These cotyledons were detachedand placed in a humid chamber to induce pycnidia formation. After three dayscirri of conidia were transferred to a plate with PDA supplemented with antibioticsas mentioned above. The identity of these isolates of L. biglobosa wereconfirmed by pigment production on PDA medium and by PCR assay usingspecies-specific primers. To our knowledge, this is the first report of L. biglobosa ´brassicae´as a pathogen of canola in Argentina. This finding shows that in Argentina´scanola cropping areas not 50 only L. maculans but alsoL.biglobosa are the causal agents of Phoma leaf spot disease.Fil: Rossi, Franco Rubén. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); ArgentinaFil: Romero, Fernando Matias. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); ArgentinaFil: Garriz, Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); ArgentinaFil: Ruiz, Oscar Adolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Instituto de Fisiología y Recursos Genéticos Vegetales; Argentin
Living healthier for longer: comparative effects of three heart-healthy behaviors on life expectancy with and without cardiovascular disease
Background: Non-smoking, having a normal weight and increased levels of physical activity are perhaps the three key factors for preventing cardiovascular disease (CVD). However, the relative effects of these factors on healthy longevity have not been well described. We aimed to calculate and compare the effects of non-smoking, normal weight and physical activity in middle-aged populations on life expectancy with and without cardiovascular disease.
Methods: Using multi-state life tables and data from the Framingham Heart Study (n = 4634) we calculated the effects of three heart healthy behaviours among populations aged 50 years and over on life expectancy with and without cardiovascular disease. For the life table calculations, we used hazard ratios for 3 transitions (No CVD to CVD, no CVD to death, and CVD to death) by health behaviour category, and adjusted for age, sex, and potential confounders.
Results: High levels of physical activity, never smoking (men), and normal weight were each associated with 20-40% lower risks of developing CVD as compared to low physical activity, current smoking and obesity, respectively. Never smoking and high levels of physical activity reduced the risks of dying in those with and without a history of CVD, but normal weight did not. Never-smoking was associated with the largest gains in total life expectancy (4.3 years, men, 4.1 years, women) and CVD-free life expectancy (3.8 and 3.4 years, respectively). High levels of physical activity and normal weight were associated with lesser gains in total life expectancy (3.5 years, men and 3.4 years, women, and 1.3 years, men and 1.0 year women, respectively), and slightly lesser gains in CVD-free life expectancy (3.0 years, men and 3.1 years, women, and 3.1 years men and 2.9 years women, respectively). Normal weight was the only behaviour associated with a reduction in the number of years lived with CVD (1.8 years, men and 1.9 years, women).
Conclusions: Achieving high levels of physical activity, normal weight, and never smoking, are effective ways to prevent cardiovascular disease and to extend total life expectancy and the number of years lived free of CVD. Increasing the prevalence of normal weight could further reduce the time spent with CVD in the population
Open source software ecosystems quality analysis from data sources
Background: Open source software (OSS) and software ecosystems (SECOs) are two consolidated research areas in software engineering. The adoption of OSS by firms, governments, researchers and practitioners has been increasing rapidly in the last decades, and in consequence, they find themselves in a new kind of ecosystem composed by software communities,foundations, developers and partners, namely Open Source Software Ecosystem (OSSECO). In order to perform a systematic
quality evaluation of a SECO, it is necessary to define certain types of concrete elements. This means that measures and evaluations should be described (e.g., through thresholds or expert judgment). The quality evaluation of an OSSECO may serve several purposes, for example: adopters of the products of the OSSECO may want to know about the liveliness of the OSSECO (e.g., recent updates); software developers may want to know about the activeness (e.g., how many collaborators are involved and how active they are); and the OSSECO community itself to know about the OSSECO health (e.g., evolving in the right direction). However, the current approaches for evaluating software quality (even those specific for open source software) do not cover all the aspects relevant in an OSSECO from an ecosystem perspective.
Goal: The main goal of this PhD thesis is to support the OSSECO quality evaluation by designing a framework that supports the
quality evaluation of OSSECOs.
Methods: To accomplish this goal, we have used and approach based on design science methodology by Wieringa [1] and the
characterization of software engineering proposed by M. Shaw [2], in order to produce a set of artefacts to contribute in thequality evaluation of OSSECOs and to learn about the effects of using these artefacts in practice.
Results: We have conducted a systematic mapping to characterize OSSECOs and designed the QuESo framework (a framework to evaluate the OSSECO quality) composed by three artifacts: (i) QuESo-model, a quality model for OSSECOs; (ii) QuESoprocess, a process for conducting OSSECO quality evaluations using the QuESo-model; and (iii) QuESo-tool, a software component to support semi-automatic quality evaluation of OSSECOs. Furthermore, this framework has been validated with a case study on Eclipse.
Conclusions: This thesis has contributed to increase the knowledge and understanding of OSSECOs, and to support the qualityevaluation of OSSECOs.
[ntecedentes: el software de código abierto (OSS, por sus siglas en inglés) y los ecosistemas de software (SECOs, por sus siglas en inglés) son dos áreas de investigación consolidadas en ingeniería de software. La adopción de OSS por parte de empresas, gobiernos, investigadores y profesionales se ha incrementado rápidamente en las últimas décadas, y, en consecuencia, todos ellos hacen parte de un nuevo tipo de ecosistema formado por comunidades de software, fundaciones, desarrolladores y socios denominado ecosistema de software de código abierto. (OSSECO, por sus siglas en inglés)). Para realizar una evaluación sistemática de la calidad de un SECO, es necesario definir ciertos tipos de elementos concretos. Esto significa que tanto las métricas como las evaluaciones deben ser descritos (por ejemplo, a través de datos históricos o el conocimiento de expertos). La evaluación de la calidad de un OSSECO puede ser de utilidad desde diferentes perspectivas, por ejemplo: los que adoptan los productos del OSSECO pueden querer conocer la vitalidad del OSSECO (por ejemplo, el número de actualizaciones recientes); los desarrolladores de software pueden querer saber sobre la actividad del OSSECO (por ejemplo, cuántos colaboradores están involucrados y qué tan activos son); incluso la propia comunidad del OSSECO para conocer el estado de salud del OSSECO (por ejemplo, si está evolucionando en la dirección correcta). Sin embargo, los enfoques actuales para evaluar la calidad del software (incluso aquellos específicos para el software de código abierto) no cubren todos los aspectos relevantes en un OSSECO desde una perspectiva ecosistémica. Objetivo: El objetivo principal de esta tesis doctoral es apoyar la evaluación de la calidad de OSSECO mediante el diseño de un marco de trabajo que ayude a la evaluación de la calidad de un OSSECO. Métodos: Para lograr este objetivo, hemos utilizado un enfoque basado en la metodología design science propuesta por Wieringa [1]. Adicionalmente, nos hemos basado en la caracterización de la ingeniería de software propuesta por M. Shaw [2], con el fin de construir un conjunto de artefactos que contribuyan en la evaluación de la calidad de un OSSECO y para conocer los efectos del uso de estos artefactos en la práctica. Resultados: Hemos realizado un mapeo sistemático para caracterizar los OSSECOs y hemos diseñado el marco de trabajo denominado QuESo (es un marco de trabajo para evaluar la calidad de los OSSECOs). QuESo a su vez está compuesto por tres artefactos: (i) QuESo-model, un modelo de calidad para OSSECOs; (ii) QuESo-process, un proceso para llevar a cabo las evaluaciones de calidad de OSSECOs utilizando el modelo QuESo; y (iii) QuESo-tool, un conjunto de componentes de software que apoyan la evaluación de calidad de los OSSECOs de manera semiautomática. QuESo ha sido validado con un estudio de caso sobre Eclipse. Conclusiones: esta tesis ha contribuido a aumentar el conocimiento y la comprensión de los OSSECOs, y tambien ha apoyado la evaluación de la calidad de los OSSECO
Open source software ecosystems quality analysis from data sources
Background: Open source software (OSS) and software ecosystems (SECOs) are two consolidated research areas in software engineering. The adoption of OSS by firms, governments, researchers and practitioners has been increasing rapidly in the last decades, and in consequence, they find themselves in a new kind of ecosystem composed by software communities,foundations, developers and partners, namely Open Source Software Ecosystem (OSSECO). In order to perform a systematic
quality evaluation of a SECO, it is necessary to define certain types of concrete elements. This means that measures and evaluations should be described (e.g., through thresholds or expert judgment). The quality evaluation of an OSSECO may serve several purposes, for example: adopters of the products of the OSSECO may want to know about the liveliness of the OSSECO (e.g., recent updates); software developers may want to know about the activeness (e.g., how many collaborators are involved and how active they are); and the OSSECO community itself to know about the OSSECO health (e.g., evolving in the right direction). However, the current approaches for evaluating software quality (even those specific for open source software) do not cover all the aspects relevant in an OSSECO from an ecosystem perspective.
Goal: The main goal of this PhD thesis is to support the OSSECO quality evaluation by designing a framework that supports the
quality evaluation of OSSECOs.
Methods: To accomplish this goal, we have used and approach based on design science methodology by Wieringa [1] and the
characterization of software engineering proposed by M. Shaw [2], in order to produce a set of artefacts to contribute in thequality evaluation of OSSECOs and to learn about the effects of using these artefacts in practice.
Results: We have conducted a systematic mapping to characterize OSSECOs and designed the QuESo framework (a framework to evaluate the OSSECO quality) composed by three artifacts: (i) QuESo-model, a quality model for OSSECOs; (ii) QuESoprocess, a process for conducting OSSECO quality evaluations using the QuESo-model; and (iii) QuESo-tool, a software component to support semi-automatic quality evaluation of OSSECOs. Furthermore, this framework has been validated with a case study on Eclipse.
Conclusions: This thesis has contributed to increase the knowledge and understanding of OSSECOs, and to support the qualityevaluation of OSSECOs.
[ntecedentes: el software de código abierto (OSS, por sus siglas en inglés) y los ecosistemas de software (SECOs, por sus siglas en inglés) son dos áreas de investigación consolidadas en ingeniería de software. La adopción de OSS por parte de empresas, gobiernos, investigadores y profesionales se ha incrementado rápidamente en las últimas décadas, y, en consecuencia, todos ellos hacen parte de un nuevo tipo de ecosistema formado por comunidades de software, fundaciones, desarrolladores y socios denominado ecosistema de software de código abierto. (OSSECO, por sus siglas en inglés)). Para realizar una evaluación sistemática de la calidad de un SECO, es necesario definir ciertos tipos de elementos concretos. Esto significa que tanto las métricas como las evaluaciones deben ser descritos (por ejemplo, a través de datos históricos o el conocimiento de expertos). La evaluación de la calidad de un OSSECO puede ser de utilidad desde diferentes perspectivas, por ejemplo: los que adoptan los productos del OSSECO pueden querer conocer la vitalidad del OSSECO (por ejemplo, el número de actualizaciones recientes); los desarrolladores de software pueden querer saber sobre la actividad del OSSECO (por ejemplo, cuántos colaboradores están involucrados y qué tan activos son); incluso la propia comunidad del OSSECO para conocer el estado de salud del OSSECO (por ejemplo, si está evolucionando en la dirección correcta). Sin embargo, los enfoques actuales para evaluar la calidad del software (incluso aquellos específicos para el software de código abierto) no cubren todos los aspectos relevantes en un OSSECO desde una perspectiva ecosistémica. Objetivo: El objetivo principal de esta tesis doctoral es apoyar la evaluación de la calidad de OSSECO mediante el diseño de un marco de trabajo que ayude a la evaluación de la calidad de un OSSECO. Métodos: Para lograr este objetivo, hemos utilizado un enfoque basado en la metodología design science propuesta por Wieringa [1]. Adicionalmente, nos hemos basado en la caracterización de la ingeniería de software propuesta por M. Shaw [2], con el fin de construir un conjunto de artefactos que contribuyan en la evaluación de la calidad de un OSSECO y para conocer los efectos del uso de estos artefactos en la práctica. Resultados: Hemos realizado un mapeo sistemático para caracterizar los OSSECOs y hemos diseñado el marco de trabajo denominado QuESo (es un marco de trabajo para evaluar la calidad de los OSSECOs). QuESo a su vez está compuesto por tres artefactos: (i) QuESo-model, un modelo de calidad para OSSECOs; (ii) QuESo-process, un proceso para llevar a cabo las evaluaciones de calidad de OSSECOs utilizando el modelo QuESo; y (iii) QuESo-tool, un conjunto de componentes de software que apoyan la evaluación de calidad de los OSSECOs de manera semiautomática. QuESo ha sido validado con un estudio de caso sobre Eclipse. Conclusiones: esta tesis ha contribuido a aumentar el conocimiento y la comprensión de los OSSECOs, y tambien ha apoyado la evaluación de la calidad de los OSSECOsPostprint (published version
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