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Search Results: 1 - 10 of 7861 matches for " Hans Schurer "
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How Rapid is Rapid Prototyping? Analysis of ESPADON Programme Results
Brigitte Saget,Mark Thomas,Hans Schurer,Denis Aulagnier
EURASIP Journal on Advances in Signal Processing , 2003, DOI: 10.1155/s1687617203212129
Abstract: New methodologies, engineering processes, and support environments are beginning to emerge for embedded signal processing systems. The main objectives are to enable defence industry to field state-of-the-art products in less time and with lower costs, including retrofits and upgrades, based predominately on commercial off the shelf (COTS) components and the model-year concept. One of the cornerstones of the new methodologies is the concept of rapid prototyping. This is the ability to rapidly and seamlessly move from functional design to the architectural design to the implementation, through automatic code generation tools, onto real-time COTS test beds. In this paper, we try to quantify the term ¢ € rapid ¢ € and provide results, the metrics, from two independent benchmarks, a radar and sonar beamforming application subset. The metrics show that the rapid prototyping process may be sixteen times faster than a conventional process.
Ground state properties of ultracold trapped bosons with an immersed ionic impurity
J. M. Schurer,P. Schmelcher,A. Negretti
Physics , 2014, DOI: 10.1103/PhysRevA.90.033601
Abstract: We consider a trapped atomic ensemble of interacting bosons in the presence of a single trapped ion in a quasi one dimensional geometry. Our study is carried out by means of the newly developed multilayer-multiconfiguration time-dependent Hartree method for bosons, a numerical exact approach to simulate quantum many-body dynamics. In particular, we are interested in the scenario by which the ion is so strongly trapped that its motion can be effectively neglected. This enables us to focus on the atomic ensemble only. With the development of a model potential for the atom-ion interaction, we are able to numerically obtain the exact many-body ground state of the atomic ensemble in the presence of an ion. We analyse the influence of the atom number and the atom-atom interaction on the ground state properties. Interestingly, for weakly interacting atoms, we find that the ion impedes the transition from the ideal gas behaviour to the Thomas-Fermi limit. Furthermore, we show that this effect can be exploited to infer the presence of the ion both in the momentum distribution of the atomic cloud and by observing the interference fringes occurring during an expansion of the quantum gas. In the strong interacting regime, the ion modifies the fragmentation process in dependence of the atom number parity which allows a clear identification of the latter in expansion experiments. Hence, we propose in both regimes experimentally viable strategies to assess the impact of the ion on the many-body state of the atomic gas. This study serves as the first building block for systematically investigate many-body physics of such hybrid system.
Capture Dynamics of Ultracold Atoms in the Presence of an Impurity Ion
J. M. Schurer,A. Negretti,P. Schmelcher
Physics , 2015, DOI: 10.1088/1367-2630/17/8/083024
Abstract: We explore the quantum dynamics of a one-dimensional trapped ultracold ensemble of bosonic atoms triggered by the sudden creation of a single ion. The numerical simulations are performed by means of the ab initio multiconfiguration time-dependent Hartree method for bosons which takes into account all correlations. The dynamics is analyzed via a cluster expansion approach, adapted to bosonic systems of fixed particle number, which provides a comprehensive understanding of the occurring many-body processes. After a transient during which the atomic ensemble separates into fractions which are unbound and bound with respect to the ion, we observe an oscillation in the atomic density which we attribute to the additional length and energy scale induced by the attractive long-range atom-ion interaction. This oscillation is shown to be the main source of spatial coherence and population transfer between the bound and the unbound atomic fraction. Moreover, the dynamics exhibits collapse and revival behavior caused by the dynamical build-up of two-particle correlations demonstrating that a beyond mean-field description is indispensable.
Impact of Many-Body Correlations on the Dynamics of an Ion-Controlled Bosonic Josephson Junction
J. M. Schurer,R. Gerritsma,P. Schmelcher,A. Negretti
Physics , 2015,
Abstract: We investigate an atomic ensemble of interacting bosons trapped in a symmetric double well potential in contact with a single tightly trapped ion which has been recently proposed [R. Gerritsma et al., Phys. Rev. Lett. 109, 080402 (2012)] as a source of entanglement between a Bose-Einstein condensate and an ion. Compared to the previous study, the present work aims at performing a detailed and accurate many-body analysis of such combined atomic quantum system by means of the ab-initio multi-configuration time-dependent Hartree method for bosons, which allows to take into account all correlations in the system. The analysis elucidates the importance of quantum correlations in the bosonic ensemble and reveals that entanglement generation between an ion and a condensate is indeed possible, as previously predicted. Moreover, we provide an intuitive picture of the impact of the correlations on the out-of-equilibrium dynamics by employing a natural orbital analysis which we show to be indeed experimentally verifiable.
Network Economies for the Internet-Application Models  [PDF]
Hans Gottinger
iBusiness (IB) , 2011, DOI: 10.4236/ib.2011.34042
Abstract: We propose a decentralized model of network and server economies, where we show efficient QoS (Quality of Service) provisioning and Pareto allocation of resources (network and server resources) among agents and suppliers, which are either network routers or servers (content providers). Specifically, it is shown 1) how prices for resources are set at the suppliers based on the QoS demands from the agents and 2) how dynamic routing algorithms and admission control mechanisms based on QoS preferences emerge from the user classes for the network economy.
Fatal Complications and Early Death after Surgical Treatment of Lung Cancer in 2000 and 2010. A Population Based Study  [PDF]
Hans Rostad
Surgical Science (SS) , 2013, DOI: 10.4236/ss.2013.41019

In the year 2000 lung cancer was operated in 349 patients in Norway, in 2010 the number was 461. In the first period fatal surgical hemorrhage occurred in eight patients, in four of them peroperatively. Postoperative hemorrhage occurred in four patients in the year 2000 and in two in 2010. Ten patients died intra- or postoperatively in the two periods which is a mortality rate within 30 days after surgery of 4.3% in the first and 1.1% in the second period. Pneumonectomy was performed in 34 patients in 2000 and eight in 2010, respectively. Altogether 19 patients died within six months after surgery without having experienced surgical complications. Pneumonectomy should not be performed in elderly and debilitated persons.

On the Foundations of Guidelines for Health Economic Assessment  [PDF]
Hans Keiding
Open Journal of Social Sciences (JSS) , 2016, DOI: 10.4236/jss.2016.45004

In recent years, increased attention has been given to guidelines for cost-effectiveness analysis of medical interventions, and some of these guidelines (such as NICE [1]) have become rather influential. In the paper, we present a model of retrieving and processing information to be used for the study of guidelines and their use. Our main result, which relies on a version of the theorem of Blackwell [2], shows that in cases where there are sufficiently many decisions to be made on the basis of the information obtained, there can be no other objective ranking of methods than the trivial one ranking more information is higher than less information. In our context, this means that guidelines may have administrative advantages but cannot be considered as a scientifically based approach to better decision making.

Modeling the effects of dust evolution on the SEDs of galaxies of different morphological type
A. Schurer,F. Calura,L. Silva,A. Pipino,G. L. Granato,F. Matteucci,R. Maiolino
Physics , 2009, DOI: 10.1111/j.1365-2966.2009.14441.x
Abstract: We present photometric evolution models of galaxies, in which, in addition to the stellar component, the effects of an evolving dusty interstellar medium have been included with particular care. Starting from the work of Calura, Pipino & Matteucci (2008), in which chemical evolution models have been used to study the evolution of both the gas and dust components of the interstellar medium in the solar neighbourhood, elliptical and irregular galaxies, it has been possible to combine these models with a spectrophotometric stellar code that includes dust reprocessing (GRASIL) (Silva et al. 1998) to analyse the evolution of the spectral energy distributions (SED) of these galaxies. We test our models against observed SEDs both in the local universe and at high redshift and use them to predict how the percentage of reprocessed starlight evolves for each type of galaxy. The importance of following the dust evolution is investigated by comparing our results with those obtained by adopting simple assumptions to treat this component.
Echinococcosis: An Economic Evaluation of a Veterinary Public Health Intervention in Rural Canada
Janna M. Schurer,Ellen Rafferty?,Marwa Farag?,Wu Zeng?,Emily J. Jenkins
PLOS Neglected Tropical Diseases , 2015, DOI: 10.1371/journal.pntd.0003883
Abstract: Echinococcosis is a rare but endemic condition in people in Canada, caused by a zoonotic cestode for which the source of human infection is ingestion of parasite eggs shed by canids. The objectives of this study were to identify risk factors associated with infection and to measure the cost-utility of introducing an echinococcosis prevention program in a rural area. We analyzed human case reports submitted to the Canadian Institutes for Health Information between 2002 and 2011. Over this 10 year period, there were 48 cases associated with E. granulosus/E. canadensis, 16 with E. multilocularis, and 251 cases of echinococcosis for which species was not identified (total 315 cases). Nationally, annual incidence of echinococcosis was 0.14 cases per 100 000 people, which is likely an underestimate due to under-diagnosis and under-reporting. Risk factors for echinococcosis included female gender, age (>65 years), and residing in one of the northern territories (Nunavut, Yukon, or Northwest Territories). The average cost of treating a case of cystic echinococcosis in Canada was $8,842 CAD. Cost-utility analysis revealed that dosing dogs with praziquantel (a cestocide) at six week intervals to control cystic echinococcosis is not currently cost-effective at a threshold of $20,000-100,000 per Quality Adjusted Life Year (QALY) gained, even in a health region with the highest incidence rate in Canada ($666,978 -755,051 per QALY gained). However, threshold analysis demonstrated that the program may become cost-saving at an echinococcosis incidence of 13-85 cases per 100,000 people and therefore, even one additional CE case in a community of 9000 people could result in the monetary benefits of the program outweighing costs.
Parasitic Zoonoses: One Health Surveillance in Northern Saskatchewan
Janna M. Schurer ,Momar Ndao,Stuart Skinner,James Irvine,Stacey A. Elmore,Tasha Epp,Emily J. Jenkins
PLOS Neglected Tropical Diseases , 2013, DOI: 10.1371/journal.pntd.0002141
Abstract: We report the results of a joint human-animal health investigation in a Dene community in northern Saskatchewan, where residents harvest wildlife (including moose, bear, elk, and fish), live in close contact with free roaming dogs, and lack access to permanent veterinary services. Fecal analysis of owned and free-roaming dogs over two consecutive years (N = 92, 103) identified several parasites of public health concern, including Toxocara canis, Diphyllobothrium spp., Echinococcus/Taenia, Cryptosporidium spp. and Giardia spp. Administration of pyrantel pamoate to a subset of dogs (N = 122) in the community in the first year was followed by reduced shedding of T. canis and other roundworms in the second year, demonstrating the potential utility of canine de-worming as a public health intervention. Using direct agglutination tests with confirmatory indirect fluorescent antibody test, 21% of 47 dogs were sero-positive for exposure to Toxoplasma gondii. Using enzyme-linked immunosorbent assay (ELISA) sero-prevalence rates in 201 human volunteers were as follows: Toxoplasma gondii (14%), Echinococcus granulosus (48%), Toxocara canis (13%) and Trichinella spp. (16%). Overall 65% of participants were sero-positive for at least one parasite. A survey administered to volunteers indicated few associations between widely accepted risk factors for parasite exposure and serological status, emphasizing the importance of environmental transmission of these parasites through soil, food, and waterborne routes.
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