VU Amsterdam

Amsterdam-Zuidoost, Netherlands

VU Amsterdam

Amsterdam-Zuidoost, Netherlands
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Andree B.P.J.,VU Amsterdam | Diogo V.,VU Amsterdam | Koomen E.,VU Amsterdam
Renewable and Sustainable Energy Reviews | Year: 2017

Policy schemes that aim to stimulate the cultivation of biofuel crops typically ignore the spatial heterogeneity in costs and benefits associated with their production. Because of spatial heterogeneity in biophysical, and current agricultural production factors, potential gains from stimulating biofuel crops are non-uniformly distributed across space. This paper explores implications of this type of heterogeneity for the net benefits associated with different subsidy schemes. We present a simple framework based on discounted cash flows, to assess potential gains from introducing the notion of heterogeneity into stimulation schemes. We show that agricultural subsidy spending can be reduced in a Pareto efficient way and simultaneously improve the total stimulation potential of biofuel policies, when schemes: 1) are production based instead of land based; 2) accommodate differences in opportunity costs, and 3) target sites where subsidies for conventional agricultural land-use types are high. These results are robust for a range of different bioenergy prices and the relative gains of addressing these key elements in policy compared to conventional stimulation schemes increase with lower bioenergy prices, and are largest when low prices coincide with high emission reduction ambitions. © 2016 The Authors

News Article | February 16, 2017

A new study led by American Cancer Society researchers in collaboration with leading experts concludes that physical activity should be routinely assessed during the doctor-patient encounter, and that clinicians should design in collaboration with their patients a detailed physical activity plan with goals that should be set and monitored. The study uses concepts from public health and behavioral economics to provide practical advice to clinicians on effective counseling to patients. The study appears early online in CA: A Cancer Journal for Clinicians. Below are highlights of the study: "Physical activity is a modifiable behavior that has the potential to prevent numerous diseases, however, so many of us are not sufficiently active. Both conscious and unconscious factors are at play that influence our behavior." said Dr. Shuval. "It's difficult to choose activities we 'should' do over those we 'want' to do. Clinicians can help play a role in creating strategies, like encouraging the use of pre-commitment contracts, which impose constraints on our 'future selves' to act in a way the will benefit us in the long run." Additional study authors include: Jeffrey Drope, PhD (American Cancer Society), David Katz, MD MPH (Yale-Griffin Prevention Research Center), Alpa Patel, PhD (American Cancer Society), Melissa Maitin-Shepard, MPP (American Cancer Society Cancer Action Network), On Amir, PhD (University of California San-Diego), Amir Grinstein, PhD (Northeastern University and VU Amsterdam). Article: Physical activity counseling in primary care: Insights from public health and behavioral economics. CA: A Cancer Journal for Clinicians. doi:10.3322/caac.21394

Frost J.,VU Amsterdam | Okun S.,PatientsLikeMe Inc. | Vaughan T.,PatientsLikeMe Inc. | Heywood J.,PatientsLikeMe Inc. | Wicks P.,PatientsLikeMe Inc.
Journal of Medical Internet Research | Year: 2011

Background: Evaluating a new use for an existing drug can be expensive and time consuming. Providers and patients must all too often rely upon their own individual-level experience to inform clinical practice, which generates only anecdotal and unstructured data. While academic-led clinical trials are occasionally conducted to test off-label uses of drugs with expired patents, this is relatively rare. In this work, we explored how a patient-centered online research platform could supplement traditional trials to create a richer understanding of medical products postmarket by efficiently aggregating structured patient-reported data. PatientsLikeMe is a tool for patients, researchers, and caregivers (currently 82,000 members across 11 condition-based communities) that helps users make treatment decisions, manage symptoms, and improve outcomes. Members enter demographic information, longitudinal treatment, symptoms, outcome data, and treatment evaluations. These are reflected back as longitudinal health profiles and aggregated reports. Over the last 3 years, patients have entered treatment histories and evaluations on thousands of medical products. These data may aid in evaluating the effectiveness and safety of some treatments more efficiently and over a longer period of time course than is feasible through traditional trials. Objective: The objective of our study was to examine the illustrative cases of amitriptyline and modafinil - drugs commonly used off-label. Methods: We analyzed patient-reported treatment histories and drug evaluations for each drug, examining prevalence, treatment purpose, and evaluations of effectiveness, side effects, and burden. Results: There were 1948 treatment histories for modafinil and 1394 treatment reports for amitriptyline reported across five PatientsLikeMe communities (multiple sclerosis, Parkinson's disease, mood conditions, fibromyalgia/chronic fatigue syndrome, and amyotrophic lateral sclerosis). In these reports, the majority of members reported taking the drug for off-label uses. Only 34 of the 1755 (1%) reporting purpose used modafinil for an approved purpose (narcolepsy or sleep apnea). Only 104 out of 1197 members (9%) reported taking amitriptyline for its approved indication, depression. Members taking amitriptyline for off-label purposes rated the drug as more effective than those who were taking it for its approved indication. While dry mouth is a commonly reported side effect of amitriptyline for most patients, 88 of 220 (40%) of people with amyotrophic lateral sclerosis on the drug reported taking advantage of this side effect to treat their symptom of excess saliva. Conclusions: Patient-reported outcomes, like those entered within PatientsLikeMe, offer a unique real-time approach to understand utilization and performance of treatments across many conditions. These patient-reported data can provide a new source of evidence about secondary uses and potentially identify targets for treatments to be studied systematically in traditional efficacy trials.

Sedmik R.I.P.,VU Amsterdam | Borghesani A.F.,University of Padua | Heeck K.,VU Amsterdam | Iannuzzi D.,VU Amsterdam
Physics of Fluids | Year: 2013

A customized atomic force microscope has been utilized in dynamic mode to measure hydrodynamic forces between a sphere and a flat plate, both coated with gold. In order to study the influence of the mean free path on slippage without systematic errors due to varying surface properties, all data have been acquired at precisely the same spot on the plate. Local accommodation coefficients and slip lengths have been extracted from experimental data for He, Ne, Ar, Kr, as well as N2, CO2, and C2H6, at Knudsen numbers between 3 × 10-4 and 3. We found that slippage is effectively suppressed if the mean free path of the fluid is lower than the roughness amplitude on the surface, while we could not observe a clear correlation between the accommodation coefficient and the molecular mass. © 2013 AIP Publishing LLC.

Sneed H.M.,Anecon GmbH | Verhoef C.,VU Amsterdam
Proceedings of IEEE International Symposium on Web Systems Evolution, WSE | Year: 2013

The following paper proposes a structured, natural language specification of web service behavior based on keywords in context. The advantage of this type of document is that it can be automatically analyzed in order to extract test cases for testing the web service. The test cases define not only what to test, i.e. what operations to invoke in what order, but also how to test, i.e. with what test data values. Our goal is to join requirement specification with test specification in one document which is used to both specify what the user requires from a service and to test if a particular service is providing it. On the one hand, a requirement table is generated from the text to compare with the functions offered. On the other hand a test case table is generated for executing those functions. From the test case table a test script is generated and from that test requests are produced. The test script is also used to validate the responses. All of the information required for both request generation and response validation is taken from the original service requirement specification. A case study depicts how the requirement document is processed. © 2013 IEEE.

Harvey N.J.A.,UBC | Olver N.,VU Amsterdam
Proceedings of the Annual ACM-SIAM Symposium on Discrete Algorithms | Year: 2014

Pipage rounding is a dependent random sampling technique that has several interesting properties and diverse applications. One property that has been useful in applications is negative correlation of the resulting vector. There are some further properties that would be interesting to derive, but do not seem to follow from negative correlation. In particular, recent concentration results for sums of independent random matrices are not known to extend to a negatively dependent setting. We introduce a simple but useful technique called concavity of pessimistic estimators. This technique allows us to show concentration of submodular functions and concentration of matrix sums under pipage rounding. The former result answers a question of Chekuri et al. (2009). To prove the latter result, we derive a new variant of Lieb's celebrated concavity theorem in matrix analysis. We provide numerous applications of these results. One is to spectrally-thin trees, a spectral analog of the thin trees that played a crucial role in the recent breakthrough on the asymmetric traveling salesman problem. We show a polynomial time algorithm that, given a graph where every edge has effective conductance at least K, returns an O(K -1· logn/loglogn)-spectrally- Thin tree. There are further applications to rounding of semidefinite programs and to a geometric question of extracting a nearly-orthonormal basis from an isotropic distribution. Copyright © 2014 by the Society for Industrial and Applied Mathematics.

Ryszka K.,VU Amsterdam | Withagen C.,VU Amsterdam
Environmental and Resource Economics | Year: 2016

We analyze the effect of climate policies using a two-region partial equilibrium model of resource extraction. The regions are heterogeneous in various aspects, such as in their climate policies and resource extraction costs. We obtain analytical and numerical conditions for a Green Paradox to occur as a consequence of a unilateral increase in carbon taxation and backstop subsidy. In order to assess the welfare and climate consequences of unilateral policy changes, we calibrate the model to real world parameter values. We find that forming a ‘climate coalition’ and introducing carbon taxation even in the absence of real climate concerns is the best course of action for the largest fossil fuel-using regions. © 2014, Springer Science+Business Media Dordrecht.

Reggiani A.,University of Bologna | Bucci P.,Significance | Russo G.,VU Amsterdam
International Regional Science Review | Year: 2011

Accessibility plays a fundamental role in the transport network. In fact, accessibility may be used for investigating the (un)even distribution of economic activities, or the (dis)equilibrium in the development of different regional performances. In particular, accessibility analysis can be considered as a first exploratory step in the understanding of people's needs and behaviour, especially in the framework of transport network structures. From the methodological viewpoint, accessibility has a long tradition, starting in the 1950's with the pioneering work by Hansen, who defined accessibility as the potential of opportunity for interaction. Such a definition can also be considered as an integrated framework of all subsequent definitions. The aim of this paper is to explore accessibility in the German commuting network, by focusing attention on the relevance of the impedance form associated with it. The conventional (potential) accessibility function - in the light of the related economic activities - is used as a suitable instrument to identify the major German hub/ attraction nodes. In this formulation, different types of decay functions are used as impedance forms. In our applications we consider home-to-work commuters travelling between 439 German districts, for both 2003 and 2007. We carry out a comparative analysis of the accessibility values in these years, by outlining the different emerging hierarchies, resulting from the use of different impedance forms. In addition, we explore which type of accessibility indicator best matches the connectivity network. The final aim is to identify - by means of different accessibility functions - homogeneous vs. heterogeneous characteristics of the German commuting network. © 2011 SAGE Publications.

Gavan K.B.,VU Amsterdam | Rector J.H.,VU Amsterdam | Heeck K.,VU Amsterdam | Chavan D.,VU Amsterdam | And 3 more authors.
Optics Letters | Year: 2011

Taking inspiration from conventional top-down micromachining techniques. We have fabricated a low mass gold fiber-top cantilever via align-and-shine photolithography. The cantilever is characterized by measuring its resonance frequency and mechanical quality factor. Our results show that the device grants mass sensitivity comparable to that reported for similar standard cantilevers. This proof-of-concept paves the way to series production of highly sensitive fiber-top devices for remote detection of biochemical substances. © 2011 Optical Society of America..

Woodroofe N.,Sheffield Hallam University | Amor S.,VU Amsterdam
Neuroinflammation and CNS Disorders | Year: 2014

The last decade has seen an upsurge of information on the role of immune responses in neurodegenerative disorders. In many of these diseases it is still unclear whether the innate and adaptive responses are pathogenic or play a role in repair, and thus understanding their precise roles is key to controlling these diseases by designing immune-therapeutic approaches. The connection between many neurological diseases is the realisation that the immune and nervous systems are inextricable linked, and that perturbations in this delicate balance are involved in many disorders. This has opened up new avenues for therapeutic approaches to treatment of CNS inflammatory and neurodegenerative disorders. Neuroinflammation and CNS Disorders brings together the very latest information on the interactions between the immune system and central nervous system. The first section of the book highlights the basic concepts in the field whilst the second section, the main body of the book, covers the role of the immune response in specific disorders of the central nervous system. Neuroinflammation and CNS Disorders will provide an invaluable guide for both researchers and clinicians working in this complex and dynamic field. © 2014 by John Wiley & Sons, Ltd. All rights reserved.

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