181 research outputs found
Briefwisseling van Johan de Witt (1625-1672)
No full textohan de Witt werd geboren op 24 september 1625 te Dordrecht als zoon van Jacob de Witt en Anna van den Corput en broer van Cornelis de Witt. Johan ging eerst naar de Latijnse school in Dordrecht, studeerde rechten in Leiden en promoveerde in Frankrijk. Hij vestigde zich in 1647 als advocaat in Den Haag, werd in 1650 pensionaris van Dordrecht en in 1653 raadpensionaris van Holland. Als raadpensionaris was hij de hoogste ambtenaar van het gewest Holland, voorzitter van de Hollandse Staten en lid van de Hollandse afvaardiging in de Staten-Generaal waar hij optrad als woordvoerder. Johan de Witt was verantwoordelijk voor zowel het binnenlandse als buitenlandse beleid en was zo bijna twintig jaar lang een van de meest invloedrijke figuren in de Republiek. Johan trouwde met Wendela Bicker (1635-1668) en kreeg in totaal acht kinderen waarvan er drie jong stierven. Johan de Witt schreef en ontving als raadpensionaris bijzonder veel brieven. Zijn briefwisseling is hierdoor zeer veelzijdig en bestaat onder meer uit brieven van belangrijke staatslieden, buitenlandse ambtsdragers, legeraanvoerders, wetenschappers, kunstenaars, familieleden en talloze verzoeken om een recommandatie.Verreweg de meeste brieven zijn geschreven in de periode 1653-1672, terwijl een kleiner deel uit de periode vóór 1653 dateert. Na zijn dood is zijn persoonlijk archief overgedragen aan de staat en wordt nu bewaard op het Nationaal Archief: inventaris Raadpensionaris De Witt, 3.01.17. Hoewel Johan de Witt een van de bekendste personages uit de vaderlandse geschiedenis is, is er betrekkelijk weinig onderzoek naar hem gedaan. Dit heeft voor een deel te maken met het feit dat de briefwisseling van Johan lange tijd slechts beperkt toegankelijk is geweest. Het Nationaal Archief legt momenteel de laatste hand aan een herinventarisatie en zal de collectie binnenkort volledig beschikbaar stellen voor onderzoek. Het Huygens ING heeft een project gestart met als uitgangspunt de online publicatie van de zesdelige bronneneditie van R. Fruin, N. Japikse en G.W. Kernkamp, Brieven aan en Brieven van Johan de Witt (1906-1919). Deze publicatie, die een selectie bevat van 3.038 brieven, wordt gedigitaliseerd en ontsloten op metadata als datum, correspondent, plaats, etc. In samenwerking met het Nationaal Archief en Early Modern Letters Online – EMLO – (een project van Cultures of Knowledge dat deel uitmaakt van Oxford University en Bodleian Library) beoogt het Huygens ING deze digitale collectie aan te vullen met brieven van en aan Johan de Witt die niet in de gedrukte editie zijn opgenomen. Daartoe is in september 2016 een aanvang gemaakt, waarna eind 2017 een eerste versie online raadpleegbaar zal zijn. Tot die tijd zal deze website vooral dienen om nieuws over het project en andere aan Johan de Witt gerelateerde zaken aan te kondigen. Volg ons ook via Twitter: @JohandewittN
[photograph] Portret van J. J. A. Goeverneur. /
No full textOp achterzijde foto staat: handgeschreven nota: "Aan prof. Paul Fredericq, Gron. 29 nov. '88; J. J. A. Goeverneur".Op achterzijde foto staat: reclame Godfried de JongPaul Fredericq. Portretten uit nalatenschap.Bijzondere collectie
A 1.2-mW/Channel Pitch-Matched Transceiver ASIC Employing a Boxcar-Integration-Based RX Micro-Beamformer for High-Resolution 3-D Ultrasound Imaging
No full textThis article presents a low-power and small-area transceiver application-specific integrated circuit (ASIC) for 3-D trans-fontanelle ultrasonography. A novel micro-beamforming receiver architecture that employs current-mode summation and boxcar integration is used to realize delay-and-sum on an N -element sub-array using N× fewer capacitive memory elements than conventional micro-beamforming implementations, thus reducing the hardware overhead associated with the memory elements. The boxcar integration also obviates the need for explicit anti-aliasing filtering in the analog front end, thus further reducing die area. These features facilitate the use of micro-beamforming in smaller pitch applications, as demonstrated by a prototype transceiver ASIC employing micro-beamforming on sub-arrays of N=4 elements, targeting a wearable ultrasound device that monitors brain perfusion in preterm infants via the fontanel. To meet its strict spatial resolution requirements, a 10-MHz 100- μ m-pitch piezoelectric transducer array is employed, leading to a per-element die area > 2 × smaller than prior designs employing micro-beamforming.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Bio-ElectronicsElectronic InstrumentationImPhys/Verweij groupImPhys/De Jong groupImPhys/Medical Imagin
Collective dynamics of an active system with binary particle size
No full textCollective dynamics is something that can be found in nature on macro and micro scale. Since the 90s of the previous century researchers have been interested in finding a model for this group behaviour. The dynamics of a group as a whole is only determined by shortrange interactions of the individuals. To better understand the working of this process, we make a model of this system with soft two-dimensional spheres with a active selfpropulsion force. Furthermore there are repulsion, alignment and noise interactions, all depending exclusively on nearest neighbours. We focus on binary systems with particles of two different sizes. Migrating and rotating states are typically found in systems with homogeneous sizes. We show that these states are also found in binary systems. The migrating state has circulation of particles and this leads to segregation of the small and big particles. Small particles are more likely to be found in the tip of the group, while big particles accumulate at the tail. Active noise in the system plays a role in the degree of segregation. The lower the noise is, the more segregated the system gets in the end
Continuous shear wave measurements for dynamic cardiac stiffness evaluation in pigs
No full textUltrasound-based shear wave elastography is a promising technique to non-invasively assess the dynamic stiffness variations of the heart. The technique is based on tracking the propagation of acoustically induced shear waves in the myocardium of which the propagation speed is linked to tissue stiffness. This measurement is repeated multiple times across the cardiac cycle to assess the natural variations in wave propagation speed. The interpretation of these measurements remains however complex, as factors such as loading and contractility affect wave propagation. We therefore applied transthoracic shear wave elastography in 13 pigs to investigate the dependencies of wave speed on pressure–volume derived indices of loading, myocardial stiffness, and contractility, while altering loading and inducing myocardial ischemia/reperfusion injury. Our results show that diastolic wave speed correlates to a pressure–volume derived index of operational myocardial stiffness (R = 0.75, p < 0.001), suggesting that both loading and intrinsic properties can affect diastolic wave speed. Additionally, the wave speed ratio, i.e. the ratio of systolic and diastolic speed, correlates to a pressure–volume derived index of contractility, i.e. preload-recruitable stroke work (R = 0.67, p < 0.001). Measuring wave speed ratio might thus provide a non-invasive index of contractility during ischemia/reperfusion injury.ImPhys/De Jong groupImPhys/Verweij grou
CaptureBias: Supporting Media Scholars with Ambiguity-Aware Bias Representation for News Videos
No full textIn this project we explore the presence of ambiguity in textual and visual media and its influence on accurately understanding andcapturing bias in news. We study this topic in the context of supportingmedia scholars and social scientists in their media analysis. Our focuslies on racial and gender bias as well as framing and the comparisonof their manifestation across modalities, cultures and languages. In thispaper we lay out a human in the loop approach to investigate the role ofambiguity in detection and interpretation of bias.Accepted Author ManuscriptWeb Information System
An Ultrasound Matrix Transducer for High-Frame-Rate 3-D Intra-cardiac Echocardiography
No full textObjective: Described here is the development of an ultrasound matrix transducer prototype for high-frame-rate 3-D intra-cardiac echocardiography. Methods: The matrix array consists of 16 × 18 lead zirconate titanate elements with a pitch of 160 µm × 160 µm built on top of an application-specific integrated circuit that generates transmission signals and digitizes the received signals. To reduce the number of cables in the catheter to a feasible number, we implement subarray beamforming and digitization in receive and use a combination of time-division multiplexing and pulse amplitude modulation data transmission, achieving an 18-fold reduction. The proposed imaging scheme employs seven fan-shaped diverging transmit beams operating at a pulse repetition frequency of 7.7 kHz to obtain a high frame rate. The performance of the prototype is characterized, and its functionality is fully verified. Results: The transducer exhibits a transmit efficiency of 28 Pa/V at 5 cm per element and a bandwidth of 60% in transmission. In receive, a dynamic range of 80 dB is measured with a minimum detectable pressure of 10 Pa per element. The element yield of the prototype is 98%, indicating the efficacy of the manufacturing process. The transducer is capable of imaging at a frame rate of up to 1000 volumes/s and is intended to cover a volume of 70° × 70° × 10 cm. Conclusion: These advanced imaging capabilities have the potential to support complex interventional procedures and enable full-volumetric flow, tissue, and electromechanical wave tracking in the heart.ImPhys/Verweij groupImPhys/Medical ImagingElectronic InstrumentationImPhys/De Jong grou
A Pitch-Matched Low-Noise Analog Front-End With Accurate Continuous Time-Gain Compensation for High-Density Ultrasound Transducer Arrays
No full textThis article presents a compact analog front-end (AFE) circuit for ultrasound receivers with linear-in-dB continuous gain control for time-gain compensation (TGC). The AFE consists of two variable-gain stages, both of which employ a novel complementary current-steering network (CCSN) as the interpolator to realize continuously variable gain. The first stage is a trans-impedance amplifier (TIA) with a hardware-sharing inverter-based input stage to save power and area. The TIA's output couples capacitively to the second stage, which is a class-AB current amplifier (CA). The AFE is integrated into an application-specific integrated circuit (ASIC) in a 180-nm high-voltage BCD technology and assembled with a 100 μm-pitch PZT transducer array of 8 × 8 elements. Both electrical and acoustic measurements show that the AFE achieves a linear-in-dB gain error below ±0.4 dB within a 36-dB gain range, which is > 2 × better than the prior art. Per channel, the AFE occupies 0.025 mm2 area, consumes 0.8 mW power, and achieves an input-referred noise density of 1.31 pA/√Hz.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic InstrumentationImPhys/Medical Imagin
The Severi problem for rational curves on del Pezzo surfaces
No full textThesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mathematics, 2005.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references (p. 141-142).Let X be a smooth projective surface and choose a curve C on X. Let VC be the set of all irreducible divisors on X linearly equivalent to C whose normalization is a rational curve. The Severi problem for rational curves on X with divisor class [C] consists of studying the irreducibility of the spaces VC as C varies among all curves on X. In this thesis, we prove that all the spaces VC are irreducible in the case where X is a del Pezzo surface of degree at least two. If the degree of X is one, then we prove the same result only for a general X, with the exception of V-KX, where KX is the canonical divisor of X. It is well known that for general del Pezzo surface of degree one, V-KX consists of twelve points, and thus cannot be irreducible.by Damiano Testa.Ph.D
Meartaligens en autonomisearring fan de Fryske literatuer om 1900 hinne
No full textThe decades shortly after 1900 were pivotal in the development of an (more or less) autonomous Frisian literary field. Frisian literature increasingly detached itself from the Dutch literary field, a development which literary historians generally attribute to the efforts of the young Frisian writer Douwe Kalma (1896-1953) and the members of his Young Frisian Community (Jong-Fryske Mienskip) (1915). Mostly due to his own avant-garde rhetoric, Kalma’s role has been exaggerated largely. In this article his success is put into perspective by mapping the most salient changes in the practice of writing Frisian literature in the period. The transition from a largely pseudo-oral, popular, and colloquial literature to a more intricate, personalized, highbrow literature was facilitated by broader societal developments, like the growth of the participation of the middle classes in civil society and public life, the rise of average educational levels and the subsequent growth of literacy not only in Dutch but also in Frisian. Juxtaposing Kalma with one of his contemporaries, i.e. the poet Johan Bernard Schepers (1857-1935), shows how Kalma, although undoubtedly the most radically Frisian oriented author of the two, certainly was not the only, nor the first representative of this new literary discourse
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