Where museums, libraries, and archives intersect

Diaporama d\u27une intervention au 32e congrès LIBER qui s\u27est tenu à Rome du 17 au 20 juin 2003. Exemple de coopération entre bibliothèques, musées et archives pour le développement des ressources en ligne à partir de l\u27activité du Research Libraries Group (RLG)

Engineered quasi-phase matching for nonlinear quantum optics in waveguides

Entanglement is the hallmark of quantum mechanics. Quantum entanglement -- putting two or more identical particles into a non-factorable state -- has been leveraged for applications ranging from quantum computation and encryption to high-precision metrology. Entanglement is a practical engineering resource and a tool for sidestepping certain limitations of classical measurement and communication. Engineered nonlinear optical waveguides are an enabling technology for generating entangled photon pairs and manipulating the state of single photons. This dissertation reports on: i) frequency conversion of single photons from the mid-infrared to 843nm as a tool for incorporating quantum memories in quantum networks, ii) the design, fabrication, and test of a prototype broadband source of polarization and frequency entangled photons; and iii) a roadmap for further investigations of this source, including applications in quantum interferometry and high-precision optical metrology. The devices presented herein are quasi-phase-matched lithium niobate waveguides. Lithium niobate is a second-order nonlinear optical material and can mediate optical energy conversion to different wavelengths. This nonlinear effect is the basis of both quantum frequency conversion and entangled photon generation, and is enhanced by i) confining light in waveguides to increase conversion efficiency, and ii) quasi-phase matching, a technique for engineering the second-order nonlinear response by locally altering the direction of a material's polarization vector. Waveguides are formed by diffusing titanium into a lithium niobate wafer. Quasi-phase matching is achieved by electric field poling, with multiple stages of process development and optimization to fabricate the delicate structures necessary for broadband entangled photon generation. The results presented herein update and optimize past fabrication techniques, demonstrate novel optical devices, and propose future avenues for device development. Quantum frequency conversion from 1848nm to 843nm is demonstrated for the first time, with >75% single-photon conversion efficiency. A new electric field poling methodology is presented, combining elements from multiple historical techniques with a new fast-feedback control system. This poling technique is used to fabricate the first chirped-and-apodized Type-II quasi-phase-matched structures in titanium-diffused lithium niobate waveguides, culminating in a measured phasematching spectrum that is predominantly Gaussian (R^2 = 0.80), nearly eight times broader than the unchirped spectrum, and agrees well with simulations

Searching for the effect of multiple uncontrolled interventions in BRMS

We search for the effects of 8 different (uncontrolled) interventions (1intervention per school) on the sub-concepts of learner’s (4th to 8th grade)motivation, self-regulation, and ICT competency data over the past threeyears. Data marking for intervention (yes/no), ICT competence of teachersand the presence of specially trained teachers are added to the formulas.Assessment of ICT competency in 3rd grade can be used as prior. Smoothsillustrate if the (motivation or self-regulation) concepts grow over timegrouped by intervention, school or grade. Grades are nested within schoolsand data is grouped by student. Are we missing anything

Towards a high-precision atomic gyroscope

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Physics, 2013.Cataloged from PDF version of thesis.Includes bibliographical references (pages 69-72).In this thesis, I report on the design and construction of the Rubidium Atomic Gyroscope Experiment (RAGE) at Draper Lab.by Mackenzie A. Van Camp.S.M

Measuring the Development of ICT Skills for Personalized Learning:Developing an Instrument for Dutch Primary Education

Our study investigates the development and validation of a questionnaire for competencies learners need to learn in a personalized way using ICT. 9 Dutch schools for primary education collaborate to make personalized learning with ICT evidence-informed. At these 9 iXperium schools, multidisciplinary design teams (consisting of primary school teachers and principals, teachers and students of the teacher-training program of a Dutch university of applied science, researchers from a Dutch university, and external ICT experts) design and research integrated interventions for PL with ICT. We defined personalized learning conditions before filtering the twenty-four learning objectives needed to measure development in personalized learning using ICT. The final questionnaire consists of thirty-three questions to cover the learning objectives. The validity and reliability of our questionary are analyzed in six steps. Cognitive validity (1) and a response model (2) are reported based on literature and a pilot with three iterative rounds of interviews (n=19). Internal constancy (3), confirmatory factor analysis (4), coefficient H (5) are reported after the first run of the questionnaire (n=800), and a test-retest alpha is reported after the second run of the questionnaire (n=800)

Nutritional profile of foods offered and consumed in a Belgian university canteen

Objective: To evaluate the nutritional profile of a lunch offered and consumed in a university canteen in Belgium. Design: The qualitative and quantitative content of 4365 meals theoretically available and 330 meals consumed was recorded during five weekdays spread over three weeks. Meal combinations were evaluated using a scoring system based on recommendations for Na content, energy from fat, and fruit and vegetable portions. Setting: University canteen in Belgium. Results: Only a 5 % of the meal combinations available and consumed complied with the three basic dietary recommendations for a hot lunch. The nutritional profile of the meals consumed was in line with that of the meals available. Conclusions: Our results show how the nutritional profile of what is eaten is largely determined by what is offered. To ensure overall compliance with dietary recommendations, considerable changes on the supply side, i.e. an increase in fruit and vegetable portions and a reduction in salt and fat of the lunch, are needed first in our setting. Our assessment provides baseline data to pilot a nutrient profiling intervention and shows how a nutrient profiling system can be used for meal evaluation purposes

Emplacement of inflated Pāhoehoe flows in the Naude’s Nek Pass, Lesotho remnant, Karoo continental flood basalt province: use of flow-lobe tumuli in understanding flood basalt emplacement

Physical volcanological features are presented for a 710-m-thick section, of the Naude’s Nek Pass, within the lower part of the Lesotho remnant of the Karoo Large Igneous Province. The section consists of inflated pāhoehoe lava with thin, impersistent sedimentary interbeds towards the base. There are seven discreet packages of compound and hummocky pāhoehoe lobes containing flow-lobe tumuli, making up approximately 50% of the section. Approximately 45% of the sequence consists of 14 sheet lobes, between 10 and 52-m-thick. The majority of the sheet lobes are in two packages indicating prolonged periods of lava supply capable of producing thick sheet lobes. The other sheet lobes are as individual lobes or pairs, within compound flows, suggesting brief increases in lava supply rate. We suggest, contrary to current belief, that there is no evidence that compound flows are proximal to source and sheet lobes (simple flows) are distal to source and we propose that the presence of flow-lobe tumuli in compound flows could be an indicator that a flow is distal to source. We use detailed, previously published, studies of the Thakurvadi Formation (Deccan Traps) as an example. We show that the length of a lobe and therefore the sections that are ‘medial or distal to source’ are specific to each individual lobe and are dependent on the lava supply of each eruptive event, and as such flow lobe tumuli can be used as an indicator of relative distance from source

Right-to-left shunt with hypoxemia in pulmonary hypertension

<p>Abstract</p> <p>Background</p> <p>Hypoxemia is common in pulmonary hypertension (PH) and may be partly related to ventilation/perfusion mismatch, low diffusion capacity, low cardiac output, and/or right-to-left (RL) shunting.</p> <p>Methods</p> <p>To determine whether true RL shunting causing hypoxemia is caused by intracardiac shunting, as classically considered, a retrospective single center study was conducted in consecutive patients with precapillary PH, with hypoxemia at rest (PaO₂< 10 kPa), shunt fraction (Qs/Qt) greater than 5%, elevated alveolar-arterial difference of PO₂(AaPO₂), and with transthoracic contrast echocardiography performed within 3 months.</p> <p>Results</p> <p>Among 263 patients with precapillary PH, 34 patients were included: pulmonary arterial hypertension, 21%; PH associated with lung disease, 47% (chronic obstructive pulmonary disease, 23%; interstitial lung disease, 9%; other, 15%); chronic thromboembolic PH, 26%; miscellaneous causes, 6%. Mean pulmonary artery pressure, cardiac index, and pulmonary vascular resistance were 45.8 ± 10.8 mmHg, 2.2 ± 0.6 L/min/m², and 469 ± 275 dyn.s.cm^-5, respectively. PaO₂in room air was 6.8 ± 1.3 kPa. Qs/Qt was 10.2 ± 4.2%. AaPO₂under 100% oxygen was 32.5 ± 12.4 kPa. Positive contrast was present at transthoracic contrast echocardiography in 6/34 (18%) of patients, including only 4/34 (12%) with intracardiac RL shunting. Qs/Qt did not correlate with hemodynamic parameters. Patients' characteristics did not differ according to the result of contrast echocardiography.</p> <p>Conclusion</p> <p>When present in patients with precapillary PH, RL shunting is usually not related to reopening of patent <it>foramen ovale</it>, whatever the etiology of PH.</p