79 research outputs found

    Efficient memory management in VOD disk array servers usingPer-Storage-Device buffering

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    We present a buffering technique that reduces video-on-demand server memory requirements in more than one order of magnitude. This technique, Per-Storage-Device Buffering (PSDB), is based on the allocation of a fixed number of buffers per storage device, as opposed to existing solutions based on per-stream buffering allocation. The combination of this technique with disk array servers is studied in detail, as well as the influence of Variable Bit Streams. We also present an interleaved data placement strategy, Constant Time Length Declustering, that results in optimal performance in the service of VBR streams. PSDB is evaluated by extensive simulation of a disk array server model that incorporates a simulation based admission test.This research was supported in part by the National R&D Program of Spain, Project Number TIC97-0438.Publicad

    Implementation of a Hardware/Software Platform for Real-Timedata-Intensive Applications in Hazardous Environments

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    Real-Time Technology and Applications Symposium. Brookline, MA, USA, 10-12 Oct. 1996In real-time data-intensive applications, the simultaneous achievement of the required performance and determinism is a difficult issue to address, mainly due to the time needed to perform I/O operations, which is more significant than the CPU processing time. Additional features need to be considered if these applications are intended to perform in hostile environments. In this paper, we address the implementation of a hardware/software platform designed to acquire, transfer, process and store massive amounts of information at sustained rates of several MBytes/sec, capable of supporting real-time applications with stringent throughput requirements under hazardous environmental conditions. A real-world system devoted to the inspection of nuclear power plants is presented as an illustrative examplePublicad

    A comprehensive approach in performance evaluation for modernreal-time operating systems

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    In real-time computing the accurate characterization of the performance and determinism that a particular real-time operating system/hardware combination can provide for real-time applications is essential. This issue is not properly addressed by existing performance metrics mainly due to the lack of completeness and generalization. In this paper we present a set of comprehensive, easy-to-implement and useful metrics covering three basic real-time operating system features: response to external events, intertask synchronization and resource sharing, and intertask data transferring. The evaluation of real-time operating systems using a set of fine-grained metrics is fundamental to guarantee that we can reach the required determinism in real-world applications.Publicad

    An anodeless (bare) tether experiment

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    NETT (New Electrodynamic Tether Technology) is an experiment proposed to ESA in 1991 as part of the Columbus Precursor Flights. It was originally intended to fly as an exposed payload in the Shuttle cargo bay. The main purpose was to demonstrate the electrodynamical capabilities of the innovative "bare tether" concept. The proposed conceptual design was recommended by a Scientific Panel of ESA, meeting in Heidelberg in March 1992. Unfortunately, the Precursor Flights have all but been scuttled, particularly as far as exposed payloads are concerned. The experiment, horever, is being considered in accomodation studies (APLSS, PIERS) for the European modulus of the future Space Station. Additionally, it might be possible to fly the bare tether in a Russian spacecraft

    Prone to supine surface-based registration for surgical planning in breast cancer treatment

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    Breast cancer is the most common invasive cancer in women worldwide. Many women with breast cancer have their malignant tumors detected before the lesions become clinically palpable. Occult lesions must be marked for the surgeon to ensure that they can be effectively resected. Image-guided wire localization (WGL) is the current standard of care for the excision of non-palpable carcinomas during breast conserving surgery. The integration of the information from multimodal imaging may be especially relevant in surgical planning as complement or an alternative to WGL. The combination of information from images in different positions is especially difficult due to large breast deformation. This work presents a system based on surface registration to localize the lesion in the operative position, starting from a prone MRI study and a surface of the patient in the supine positon. The pre-operative surface from the MRI is registered to the surface obtained in a supine position similar to the intraoperative setting. Triangular meshes have been used to model breast surface in both positions and surfaces are aligned using a Laplacian deformation with fiducials automatically obtained from 3 anatomical references. The evaluation of the methodology has been carried out in 13 cases in which a supine- CT was available achieving an average localization error of 6.7 m

    High dose chemotherapy and autologous stem cell transplantation in patients with peripheral T-cell lymphoma not achieving complete response after induction chemotherapy. The GEL-TAMO experience

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    Background and objectives: patients with aggressive non-Hodgkin's lymphomas (NHL) who do not obtain a complete response (CR) after induction chemotherapy have a poor prognosis. However, provided they are sensitive to the first regimen of chemotherapy, 25-40% of them with a B-cell phenotype may achieve long-term survival when treated with high dose chemotherapy and autologous stem cell transplantation (HDC/ASCT). The aim of this study was to analyze the efficacy of this therapy in the corresponding patients with peripheral T-cell lymphoma (PTCL). Design and methods: we retrospectively evaluated the efficacy of ASCT in 35 patients with PTCL from the GEL-TAMO registry, who did not achieve a CR to standard induction chemotherapy regimens for aggressive NHL. Thirty-one patients underwent transplantation after achieving a partial response (PR) and 4 patients were non-responders. Results: following HDC/ASCT, 23 (66%) of the patients achieved a CR, 4 (11%) a PR and in 7 (20%) cases the transplant failed. One patient was not evaluated because of early toxic death. With a median follow-up of the survivors of 37.5 months, 18 patients (51%) are alive and 15 patients (43%) are free of disease. Transplant-related mortality rate at 100 days was 11% and at 5 years the probabilities of survival, freedom from progression and disease-free survival for complete responders were 37%, 36% and 55% respectively. Pre-transplant lactate-dehydrogenase level, age-adjusted International Prognostic Index (aa-IPI) and tumor score correlated with survival. Interpretation and conclusions: one third of the patients with PTCL who fail to achieve CR to the first chemotherapeutic regimen can be rescued with HDC/ASCT. Pre-transplant values of IPI and tumor score risk systems for aggressive lymphomas were useful to predict subsequent survival

    Monte Carlo flattening filter design to high energy intraoperative electron beam homogenization

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    [EN] Intraoperative radiotherapy using mobile linear accelerators is used for a wide variety of malignancies. However, when large fields are used in combination with high energies, a deterioration of the flatness dose profile is measured with respect to smaller fields and lower energies. Indeed, for the LIAC HWL of Sordina, this deterioration is observed for the 12 MeV beam combined with 10 cm (or larger) diameter applicator. Aimed to solve this problem, a flattening filter has been designed and validated evaluating the feasibility of its usage at the upper part of the applicator. The design of the filter was based on Monte Carlo simulations because of its accuracy in modeling components of clinical devices, among other purposes. The LIAC 10 cm diameter applicator was modeled and simulated independently by two different research groups using two different MC codes, reproducing the heterogeneity of the 12 MeV energy beam. Then, an iterative process of filter design was carried out. Finally, the MC designed conical filter with the optimal size and height to obtain the desired flattened beam was built in-house using a 3D printer. During the experimental validation of the applicator-filter, percentage depth dose, beam profiles, absolute and peripheral dose measurements were performed to demonstrate the effectiveness of the filter addition in the applicator. These measurements conclude that the beam has been flattened, from 5.9% with the standard configuration to 1.6% for the configuration with the filter, without significant increase of the peripheral dose. Consequently, the new filter-applicator LIAC configuration can be used also in a conventional surgery room. A reduction of 16% of the output dose and a reduction of 1.1 mm in the D50 of the percentage depth dose was measured with respect to the original configuration. This work is a proof-of-concept that demonstrates that it is possible to add a filter able to flatten the beam delivered by the Sordina LIAC HWL. Future studies will focus on more refined technical solutions fully compatible with the integrity of the applicator, including its sterilization, to be safely introduced in the clinical practice.The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Giuseppe Felici reports a relationship with S.I.T. Sordina IORT Technologies S.p.A. that includes: employment. We thank the professionals and facilities at the 3D printing and metrology department in the Mechanics Unit at IFIC. JV thanks I. Diaz for measuring the PLA density. We thank S.I.T. SORDINA IORT Tech-nologies SpA for providing the applicator used for testing the filter during the measurements. JV, FB, and JP would like to acknowledge the Spanish "Ministerio de Ciencia e Innovacion" (MCIN) grant PID2021-125096NB-I00 funded by MCIN/AEI/10.13039 and the "Generalitat Valenciana" (GVA) grant PROMETEO/2021/064.Oliver-Gil, S.; Vijande, J.; Tejedor-Aguilar, N.; Miró Herrero, R.; Rovira-Escutia, JJ.; Ballester, F.; Juste-Vidal, B.... (2023). Monte Carlo flattening filter design to high energy intraoperative electron beam homogenization. Radiation Physics and Chemistry. 212. https://doi.org/10.1016/j.radphyschem.2023.11110221

    Air-sea CO2 fluxes in the Atlantic as measured during the FICARAM cruises

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    A total of fourteen hydrographic cruises spanning from 2000 to 2008 were conducted during the spring and autumn seasons between Spain and the Southern Ocean, under the framework of the Spanish research project FICARAM. The performed underway measurements are processed and analysed to describe the meridional air-sea CO2 fluxes (F CO2) along the Atlantic Ocean. The data was organised into different biogeochemical oceanographic provinces, according mainly to the thermohaline characteristics. The obtained spatial and temporal distributions of F CO2 follow the generally expected patterns and annual trends. The Subtropical regions in both hemispheres alternated the CO2 source and sink nature from autumn to spring, respectively. On the other hand, Tropical waters and the Patagonian Sea clearly behaved as sinks of atmospheric CO2 like the waters of the Drake Passage during autumn. The obtained results during the cruises also revealed significant long-term trends, such as the warming of equatorial waters (0.11±0.03 Cyr−1) and the decrease of surface salinity (−0.16±0.01 yr−1) in tropical waters caused by the influence of the Amazon River plume. This reduction in surface salinity appears to have a direct influence over the CO2 storage rates, fostering the uptake capacity of atmospheric CO2 (−0.09±0.03 molm−2 yr−1). An analysis of the biogeochemical forcing on the CO2 fugacity (fCO2) variability performed from an empirical algorithm highlighted the major role of the Amazon River input in the tropical North Atlantic fluxes. In addition, it has provided a quantitative measure of the importance of the thermodynamic control of F CO2 at temperate latitudes

    Prediction of peripheral neuropathy in multiple myeloma patients receiving bortezomib and thalidomide: a genetic study based on a single nucleotide polymorphism array

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    GEM (Grupo Español de MM)/PETHEMA (Programa para el Estudio de la Terapéutica en Hemopatías Malignas) cooperative study group.Bortezomib- and thalidomide-based therapies have significantly contributed to improved survival of multiple myeloma (MM) patients. However, treatment-induced peripheral neuropathy (TiPN) is a common adverse event associated with them. Risk factors for TiPN in MM patients include advanced age, prior neuropathy, and other drugs, but there are conflicting results about the role of genetics in predicting the risk of TiPN. Thus, we carried out a genome-wide association study based on more than 300 000 exome single nucleotide polymorphisms in 172 MM patients receiving therapy involving bortezomib and thalidomide. We compared patients developing and not developing TiPN under similar treatment conditions (GEM05MAS65, NCT00443235). The highest-ranking single nucleotide polymorphism was rs45443101, located in the PLCG2 gene, but no significant differences were found after multiple comparison correction (adjusted P =.1708). Prediction analyses, cytoband enrichment, and pathway analyses were also performed, but none yielded any significant findings. A copy number approach was also explored, but this gave no significant results either. In summary, our study did not find a consistent genetic component associated with TiPN under bortezomib and thalidomide therapies that could be used for prediction, which makes clinical judgment essential in the practical management of MM treatment.This work has been partially supported by grants of the Instituto de Salud Carlos III (ISCIII) (CP13/00080), ISCIII (PI12/02311), Red Temática de Investigación Cooperativa en Cáncer (RD12/0036/0069) (RD12/0036/0061), Ministerio de Economía y Competitividad/ Fondo Europeo de Desarrollo Regional (FEDER) “Una manera de hacer Europa” (Innocampus; CEI‐2010‐1‐0010), Asociación Española Contra el Cancer (GCB120981SAN), and Joan Rodes (JR 14/00016). M.E.S. is supported by the Miguel Servet program (CP13/00080) of the ISCIII (Ministerio de Economía y Competitividad).Peer Reviewe

    Calibration and performance tests of detectors for laser-accelerated protons

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    We present the calibration and performance tests carried out with two detectors for intense proton pulses accelerated by lasers. Most of the procedures were realized with proton beams of 0.46-5.60 MeV from a tandem accelerator. One approach made use of radiochromic films, for which we calibrated the relation between optical density and energy deposition over more than three orders of magnitude. The validity of these results and of our analysis algorithms has been confirmed by controlled irradiation of film stacks and reconstruction of the total beam charge for strongly non-uniform beam profiles. For the spectral analysis of protons from repeated laser shots, we have designed an online monitor based on a plastic scintillator. The resulting signal from a photomultiplier directly measured on a fast oscilloscope is especially useful for time-of-flight applications. Variable optical filters allow for suppression of saturation and an extension of the dynamic range. With pulsed proton beams we have tested the detector response to a wide range of beam intensities from single particles to 3 ×105 protons per 100 ns time interval.Project funded by the Spanish Ministry of Economy and Competitiveness and co-funded with FEDER's funds within the INNPACTO 2011 program under Grant No. IPT-2011-0862-900000. This work was supported by the Spanish Plan Nacional de Investigacion Cientifica, Desarrollo e Innovacion Tecnologica (I+D+i) under Grant No. TEC 2013-48036-C3-1-R and the Valencian Local Government under Grants PROMETEOII/2013/010 and ISIC 2011/013. The work of A. J. Gonzalez is financed by CSIC with a JAE-Doc contract under Junta de Ampliacion de Estudios program, cofinanced by the European Social Fund.Peer Reviewe
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