5,400 research outputs found
L-Band MMICs for Space-based SAR system
The design and performance of an L-Band GaAs chip-set is presented.The chip-set consists of a 6-bit attenuator circuit,a Low-Noise Amplifier (LNA)and a Multi Function Chip that is the combination of a 6-bit attenuator and 6-bit Phase shifter circuit.The chip-set is developed for the pre-flight engineering T/R (Transmit and Receive)modules currently in development with Astrium in a space-based SAR (Synthetic Aperture Radar)system.The MMICs are realised in the 0.25 µm PHEMT (PH25)technology of UMS.Only one iteration was needed for the MMICs in order to be fully compliant with the specifications
Are Dutch Skylarks partial migrants? Ring recovery data and radio-telemetry suggest local coexistence of contrasting migration strategies
In recent years, Skylarks Alauda arvensis have undergone dramatic population declines in many European countries. Evidence exists for deteriorating conditions during the breeding season, but little is known about the situation during the rest of the annual cycle. Here we use two approaches to test if the Dutch breeding population of Skylarks consists of resident and/or migratory individuals. First, we present an analysis of ring recoveries from the Dutch Ringing Centre "Vogeltrekstation". Out of 25 recoveries, 12 Skylarks were resident in winter, 10 migrated and three were classified as probable migrants. Resident birds were accompanied during winter by birds from northern and eastern Europe. Very limited natal and breeding dispersal recorded in the same dataset suggests that our results were not influenced by long dispersal distances. Next, we compared these results to a local radio-telemetry study in the northern Netherlands. During two different years we equipped a total of 27 Skylarks from a breeding population with radio-transmitters and followed them during the subsequent winter. Four birds were found to winter locally. Out of 23 individuals that we did not find in winter, 14 returned in the following breeding season to the study area, all with a working transmitter, suggesting that they wintered outside our study area. Two ring recoveries of birds from the same study population indeed showed migration to south-west Europe. Based on these two lines of evidence, we conclude local coexistence of a resident and a migrant strategy in Dutch Skylarks. The findings of our study are important for the planning of conservation efforts, as we can only protect this rapidly declining species when we know their behaviour and whereabouts throughout the entire annual cycle
Proton radiography to improve proton radiotherapy: Simulation study at different proton beam energies
To improve the quality of cancer treatment with protons, a translation of
X-ray Computed Tomography (CT) images into a map of the proton stopping powers
needs to be more accurate. Proton stopping powers determined from CT images
have systematic uncertainties in the calculated proton range in a patient of
typically 3-4\% and even up to 10\% in region containing
bone~\cite{USchneider1995,USchneider1996,WSchneider2000,GCirrone2007,HPaganetti2012,TPlautz2014,GLandry2013,JSchuemann2014}.
As a consequence, part of a tumor may receive no dose, or a very high dose can
be delivered in healthy ti\-ssues and organs at risks~(e.g. brain
stem)~\cite{ACKnopf2013}. A transmission radiograph of high-energy protons
measuring proton stopping powers directly will allow to reduce these
uncertainties, and thus improve the quality of treatment.
The best way to obtain a sufficiently accurate radiograph is by tracking
individual protons traversing the phantom
(patient)~\cite{GCirrone2007,TPlautz2014,VSipala2013}. In our simulations we
have used an ideal position sensitive detectors measuring a single proton
before and after a phantom, while the residual energy of a proton was detected
by a BaF crystal. To obtain transmission radiographs, diffe\-rent phantom
materials have been irradiated with a 3x3~cm scattered proton beam, with
various beam energies. The simulations were done using the Geant4 simulation
package~\cite{SAgostinelli2003}.
In this study we focus on the simulations of the energy loss radiographs for
various proton beam energies that are clinically available in proton
radiotherapy.Comment: 6 pages, 6 figures, Presented at Jagiellonian Symposium on
Fundamental and Applied Subatomic Physics, 7-12 June, 2015, Krak\'ow, Polan
Estimation of individual beneficial and adverse effects of intensive glucose control for patients with type 2 diabetes
AIMS/HYPOTHESIS: Intensive glucose control reduces the risk of vascular complications while increasing the risk of severe hypoglycaemia at a group level. We sought to estimate individual beneficial and adverse effects of intensive glucose control in patients with type 2 diabetes. METHODS: We performed a post hoc analysis of the Action in Diabetes and Vascular Disease: Preterax and Diamicron MR Controlled Evaluation (ADVANCE) trial, a randomised controlled trial evaluating standard vs intensive glucose control (HbA1c target ≤6.5% [48 mmol/mol]). In 11,140 participants, we estimated the individual 5 year absolute risk reduction (ARR) for the composite outcome of major micro- and macrovascular events and absolute risk increase (ARI) for severe hypoglycaemia for intensive vs standard glucose control. Predictions were based on competing risks models including clinical characteristics and randomised treatment. RESULTS: Based on these models, 76% of patients had a substantial estimated 5 year ARR for major vascular events (>1%, 5 year number-needed-to-benefit [NNTB5] 200). Similarly, 36% of patients had a substantial estimated ARI for severe hypoglycaemia (5 year number-needed-to-harm [NNTH5] 200). When assigning similar or half the weight to severe hypoglycaemia compared with a major vascular event, net benefit was positive in 85% or 99% of patients, respectively. Limiting intensive treatment to the 85% patient subgroup had no significant effect on the overall incidence of major vascular events and severe hypoglycaemia compared with treating all patients. CONCLUSIONS/INTERPRETATION: Taking account of the effects of intensive glucose control on major micro- and macrovascular events and severe hypoglycaemia for individual patients, the estimated net benefit was positive in the majority of the participants in the ADVANCE trial. The estimated individual effects can inform treatment decisions once individual weights assigned to positive and adverse effects have been specified. TRIAL REGISTRATION: ClinicalTrials.gov NCT00145925
Kennisbehoeften omtrent het beheer en behoud van audiovisuele materialen
In 2016 heeft het Nederlands Instituut voor Beeld en Geluid de eerste TrendMonitor Audiovisuele Collecties in Nederland gepubliceerd: een onderzoek naar trends in het beheer, het behoud en de beschikbaarstelling van de analoge en digitale audiovisuele collecties. Het is een tweejaarlijks onderzoek naar de trends en ontwikkelingen binnen de sector. Voor de tussenliggende jaren zijn diepgaande onderzoeken voorzien, zoals gepresenteerd in voorliggend rapport. In dit kwalitatief onderzoek is een viertal proposities van Beeld en Geluid, om in de kennisbehoefte ten aanzien van audiovisuele materialen en collecties te voorzien, onderzocht. De voorgelegde proposities zijn: 1) een kennisbank, 2) workshops, seminars en cursussen, 3) een expertnetwerk, en 4) een nieuwsbrief. Tot slot werd in het bijzonder gevraagd naar de kennisbehoefte met betrekking tot auteursrechten. De uitkomsten van dit diepte-onderzoek zijn richtinggevend voor zowel de activiteiten van AVA_Net, het netwerk van audiovisuele collectiehouders in Nederland, als die van Beeld en Geluid zelf
TrendMonitor Audiovisuele Collecties in Nederland
Het audiovisueel archief in Nederland is volop in beweging. Individuele instellingen ontvangen en verzamelen steeds meer audiovisuele producties, ontwikkelen steeds professioneler informatiebeleid en koppelen hun collecties, kennis en voorzieningen aan een groter netwerk. Er bestaat vanuit deze ontwikkeling een toenemende behoefte aan inzicht in de trends in het beheer, het behoud en de beschikbaarstelling van de analoge en digitale audiovisuele collecties. Vorig jaar is Beeld en Geluid daarom gestart met de “TrendMonitor Audiovisuele Collecties in Nederland”, een terugkerend onderzoek binnen de “sector” naar de trends en ontwikkelingen op het gebied van digitalisering en conservering, beleidsprioriteiten, kennisbehoeften, beschikbare voorzieningen, budgetten, uitdagingen en knelpunten.
De uitkomsten van de TrendMonitor zijn richtinggevend voor de agenda van AVA_Net, het netwerk van audiovisuele collectiehouders in Nederland dat wordt ondersteund door Beeld en Geluid. Voor de korte termijn hopen wij dat de Trendrapportages zullen bijdragen aan de ontwikkeling van een actieplan voor het veiligstellen van informatie op analoge dragers. Voor de lange termijn is de TrendMonitor een essentieel onderdeel voor de invulling van Nationale Strategie Digitaal Erfgoed en de positie van de audiovisuele collecties daarbinnen
Shigellosis and AIDS : Report of a case and brief review of the literature
Contains fulltext :
4491.pdf (publisher's version ) (Open Access
The use of light traps in monitoring abundance of glass eel
Door de sterke afname van de glasaalintrek verkeert de jaarlijkse bemonstering in de problemen. De kosten van het huidige arbeidsintensieve kruisnetprogramma zijn hoog en de sterke afname van de glasaalvangsten brengen de statistische betrouwbaarheid in gevaar. De ontwikkeling van een nieuwe, betrouwbare en betaalbare methode om de jaarlijkse glasaalmonitoring uit te voeren is belangrijk voor het beheer van de in zorgwekkende toestand verkerende aalstand. In 2010 is er aanvullend onderzoek gedaan naar de mogelijkheid lichtvallen in te zetten als methodiek voor het monitoren van absolute dichtheden glasaal. Het onderzoek in 2010 heeft duidelijk aangetoond dat het twijfelachtig is of lichtvallen een goed alternatief zijn voor de huidige kruisnetbemonsterin
Clinical trials in desmoid-type fibromatosis in children and adults:A systematic review
Desmoid-type fibromatosis (DTF) is a rare locally aggressive soft tissue neoplasm, which occurs in children and adults, with a peak incidence in young adults. For the majority of the patients, DTF is a chronic and symptomatic disease, which affects health-related quality of life. Systemic treatment regimens tend to differ for patients treated by pediatric oncologists compared to medical oncologists. This systematic review identified 14 clinical trials in children and adults with DTF. Tumor response and progression-free survival rates varied widely between studies and study populations. Treatment choices for patients with DTF are based on a paucity of (randomized) trials. Treatment principles of DTF are similar in pediatric and adult oncology, but the treatment itself is different. This seems mostly driven by a lack of tyrosine kinase inhibitor (TKI) accessibility in pediatric oncology. An insufficient number of studies examined patient-reported outcomes, which are extremely important for patients with a chronic disease like DTF.</p
Defining the business ecosystem of peer-to-peer electricity trading
Purpose: The purpose of this paper is to introduce the value proposition and structure of the business ecosystem of peer-to-peer electricity trading through a future oriented approach. Design/Methodology/Approach: This study follows a qualitative approach. It conducts conceptual analyses by utilizing previously validated tools in similar contexts. First, different views on business ecosystems are introduced and an argument is made to justify an ecosystem perspective for peerto-peer electricity trading. Second, the value proposition of the peer-to-peer electricity trading ecosystem is identified by utilising a meta-model which consists of four elements: end customer value, business value (shareholder value), collaborative value (business value to the supply chain) and societal value (value creation in the supply chain and control of negative externalities). Third, based on the structural view of business ecosystems, the study identifies actors, positions, links, and activities in the traditional electricity trading. And last, (structural) changes of the ecosystem for peer-to-peer electricity trading are discussed. Findings: This paper elaborates the business ecosystem of peer-to-peer electricity trading and highlights the structural changes it imposes to the status quo. Practical and social implications: The ecosystem construct adds insights into actors’ ecosystem strategy regarding their business models for peer-to-peer electricity trading as well as into the governance of this type of trading. It provides a comprehensive view for policy makers. It enhances the research designs in detailed aspects of the peer-to-peer electricity trading by providing a wide lense. Originality/Value: The identified business ecosystem of peer-to-peer electricity trading provides a comprehensive, multi-stakeholder perspective to incorporate complexities and include externalities
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