244 research outputs found

    Methodological Aspects of Prognostic Classifications: Applications in Testicular Cancer

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    Patients with similar characteristics can be grouped together in a prognostic classification to estimate a patient’s prognosis and guide treatment decisions. The topic of this thesis is methodological aspects of defining prognosis classifications. We specifically looked at patients with advanced testicular cancer, who are currently classified into good, intermediate and poor prognosis groups according to the International Germ Cell Consensus (IGCC) Classification. The IGCC classification aims to guide treatment decisions, it is used as a stratification method for clinical trials. Two main topics are investigated: (1) the validity of the IGCC classification: are the assumptions underlying the IGCC classification method valid and can the survival estimates of the IGCC classification be generalised to currently diagnosed patients, (2) alternative methods of defining prognostic groups, especially for poor prognosis patients. Validity of the IGCC classification Issues in the development of prognostic classifications are discussed, and background on testicular cancer and the development of the IGCC classification is given in Chapter 1

    mHealth : An innovative approach in periconception care

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    The main aim of this thesis is to investigate the benefits, barriers and effectiveness of the Smarter Pregnancy mHealth program regarding the adoption of healthy periconception nutrition and lifestyle and its impact on early reproductive and pregnancy outcome. The ultimate goal of this thesis is that the new knowledge as described will further substantiate the awareness of patients and health care professionals regarding the importance of healthy periconception nutrition and lifestyle. Moreover, the opportunities provided by evidence-based personalized mHealth programs to empower target groups will probably stimulate the accessibility and implementation of periconception care. Because periconception care is a form of preventive medicine in the earliest phase of life, it should be considered as the best investment in health of current and future generations

    Communication: Nanosecond folding dynamics of an alpha helix: Time-dependent 2D-IR cross peaks observed using polarization-sensitive dispersed pump-probe spectroscopy

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    We present a simple method to measure the dynamics of cross peaks in time-resolved two-dimensional vibrational spectroscopy. By combining suitably weighted dispersed pump-probe spectra, we eliminate the diagonal contribution to the 2D-IR response, so that the dispersed pump-probe signal contains the projection of only the cross peaks onto one of the axes of the 2D-IR spectrum. We apply the method to investigate the folding dynamics of an alpha-helical peptide in a temperature-jump experiment and find characteristic folding and unfolding time constants of 260 ± 30 and 580 ± 70 ns at 298 K

    A decision-analytic approach to define poor prognosis patients: A case study for non-seminomatous germ cell cancer patients

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    Background. Classification systems may be useful to direct more aggressive treatment to cancer patients with a relatively poor prognosis. The definition of 'poor prognosis' often lacks a formal basis. We propose a decision analytic approach to weigh benefits and harms explicitly to define the treatment threshold for more aggressive treatment. This approach is illustrated by a case study in advanced testicular cancer, where patients with a high risk of mortality under standard treatment may be eligible for high-dose chemotherapy with stem cell support, which is currently defined by the IGCC classification. Methods. We use

    Retention and the psychological contract : the case of financial practitioners within the Limpopo Provincial Treasury

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    The retention of scarce skilled employees is one of the major challenges affecting public service delivery. Retaining scarce skilled employees in organisations is not always strategically prioritised, despite the cost of turnover to the employer. The article is the product of research which describes the nature of the psychological contract and analyses the extent to which the Limpopo Provincial Treasury (LPT) is able to retain financial practitioners (scarce skilled employees) by focusing upon issues such as career development, motivation and attachment. The LPT faces serious staff turnover rates in scarce skilled employees, specifically pertaining to young internal auditors, which has resulted in unmet targets over the past 10 years. In this research, a questionnaire survey was used to collect data. The questionnaire comprised both closed- and open-ended questions designed to determine employee perceptions regarding the retention of scarce skilled employees. The questionnaire was distributed to 60 core employees in the LPT. The target population included internal auditors, risk management practitioners, internal control practitioners, financial management practitioners, information technology specialists, revenue management practitioners, accountants and economists. Quantitative data was analysed using descriptive statistics in the SPSS software packages, while qualitative data was analysed using thematic analysis. The results revealed that the employee morale, the lack of promotion opportunities and inadequate resource allocations were the main causes for retention failure. The research resulted in recommendations put forward for the development of an integrated human resource management policy aligned to retention through an intensive resource allocation strategy

    Theory of mind in freely-told children’s narratives: a classification approach

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    Children are the focal point for studying the link between language and Theory of Mind (ToM) competence. Language and ToM are often studied with younger children and standardized tests, but as both are social competences, data and methods with higher ecological validity are critical.We leverage a corpus of 442 freely-told stories by Dutch children aged 4-12, recorded in their everyday classroom environments, to study language and ToM with NLP-tools. We labelled stories according to the mental depth of story characters children create, as a proxy for their ToM competence ‘in action’, and built a classifier with features encoding linguistic competences identified in existing work as predictive of ToM.We obtain good and fairly robust results (F1-macro = .71), relative to the complexity of the task for humans. Our results are explainable in that we link specific linguistic features such as lexical complexity and sentential complementation, that are relatively independent of children’s ages, to higher levels of character depth. This confirms and extends earlier work, as our study includes older children and socially embedded data from a different domain. Overall, our results support the idea that language and ToM are strongly interlinked, and that in narratives the former can scaffold the latter.NWOVI.Veni.191C.051LIACS-Managemen

    Looking from the inside: how children render character’s perspectives in freely told fantasy stories

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    Story characters not only perform actions, they typically also perceive, feel, think, and communicate. Here we are interested in how children render characters’ perspectives when freely telling a fantasy story. Drawing on a sample of 150 narratives elicited from Dutch children aged 4-12, we provide an inventory of 750 instances of character-perspective representation (CPR), distinguishing fourteen different types. Firstly, we observe that character perspectives are ubiquitous in freely told children’s stories and take more varied forms than traditional frameworks can accommodate. Secondly, we discuss variation in the use of different types of CPR across age groups, finding that character perspectives are being fleshed out in more advanced and diverse ways as children grow older. Thirdly, we explore whether such variation can be meaningfully linked to automatically extracted linguistic features, thereby probing the potential for using automated tools from NLP to extract and classify character perspectives in children’s stories.NWOVI.VENI.191.C.051Computer Systems, Imagery and Medi

    Walking Behavior Change Detector for a “Smart” Walker

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    AbstractThis study investigates the design of a novel real-time system to detect walking behavior changes using an accelerometer on a rollator. No sensor is required on the user. We propose a new non-invasive approach to detect walking behavior based on the motion transfer by the user on the walker. Our method has two main steps; the first is to extract a gait feature vector by analyzing the three-axis accelerometer data in terms of magnitude, gait cycle and frequency. The second is to classify gait with the use of a decision tree of multilayer perceptrons. To assess the performance of our technique, we evaluated different sampling window lengths of 1, 3 an 5seconds and four different Neural Network architectures. The results revealed that the algorithm can distinguish walking behavior such as normal, slow and fast with an accuracy of about 86%. This research study is part of a project aiming at providing a simple and non-invasive walking behavior detector for elderly who use rollators

    Ranking responsible source assessments for building materials

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    An increasing amount of building materials is traded worldwide. The raw materials needed to construct buildings are often extracted in different places than where they are used. This creates social, economic and environmental impacts that are inflicted in other locations than where the building is constructed. To gain insight in these impacts and to be able to reduce them, certification schemes are developed. This research concentrates on the social impact of global construction material extraction and production, and can be used in multi-aspect sustainable building assessment tools. In this paper, we propose a framework for the ranking of certificates to assess the social impact of global construction material extraction and production. With this framework, new assessment schemes can objectively be added to a tool. This framework is already being integrated in BREEAM-NL, but can also be used for other countries and other assessment methods than BREEAM
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