84 research outputs found
Idle period shortening for TDD communications in large cells,”
Abstract-Time division duplex (TDD) technologies are necessary to deal with unpaired frequency bands and to allow low-complexity user equipments (UE) without duplexer in paired frequency bands. In TDD communications, a frame is divided into several sub-frames, each sub-frame being allocated to either uplink (UL) or downlink (DL). An idle period (IP) is required at a DL/UL switching point. It is usually dimensioned according to the cell radius and is identical for all UEs of the cell. In this paper, we propose a UE-specific IP duration, which increases the overall data rate of TDD communications for large cells. Numerical results show the potentially large benefit of the proposed dimensioning in term of spectral efficiency, which can be obtained without any specific signaling
The IST project MATRICE on MC-CDMA transmission techniques for future Cellular Systems
This paper presents an overview
of the European IST project MATRICE
(MC-CDMA Transmission Techniques
for Integrated Broadband Cellular
Systems, IST-2001-3220), describing
its tasks, goals and preliminary
achievements. The main focus of the
MATRICE project is the definition of
a new air-interface for future cellular
mobile radio systems based on
Multicarrier-CDMA modulation techniques
and the study of its key building blocks
like receiver algorithms and flexible
TX components. The nine European
partners participating in this project are
CEA-LETI (F), France Telecom (F),
Instituto de Telecommonicaçõ (P),
Mitsubishi Electric ITE-TCL (F), University
of Madrid (E), University of Surrey (UK),
STMicroelectronics (CH), INSA-IETR (F)
and Nokia (D)
Conserved molecular interactions in centriole-to-centrosome conversion.
Centrioles are required to assemble centrosomes for cell division and cilia for motility and signalling. New centrioles assemble perpendicularly to pre-existing ones in G1-S and elongate throughout S and G2. Fully elongated daughter centrioles are converted into centrosomes during mitosis to be able to duplicate and organize pericentriolar material in the next cell cycle. Here we show that centriole-to-centrosome conversion requires sequential loading of Cep135, Ana1 (Cep295) and Asterless (Cep152) onto daughter centrioles during mitotic progression in both Drosophila melanogaster and human. This generates a molecular network spanning from the inner- to outermost parts of the centriole. Ana1 forms a molecular strut within the network, and its essential role can be substituted by an engineered fragment providing an alternative linkage between Asterless and Cep135. This conserved architectural framework is essential for loading Asterless or Cep152, the partner of the master regulator of centriole duplication, Plk4. Our study thus uncovers the molecular basis for centriole-to-centrosome conversion that renders daughter centrioles competent for motherhood.J.F., Z.L., S.S. and N.S.D. are supported from Programme Grant to D.M.G. from Cancer Research UK. H.R. is supported from MRC Programme Grant to D.M.G. J.F. thank the British Academy and the Royal Society for Newton International Fellowship and Z.L. thanks the Federation of European Biochemical Societies for the Long-Term postdoctoral Fellowship. The authors thank Nicola Lawrence and Alex Sossick for assistance with 3D-SIM.This is the author accepted manuscript. The final version is available from NPG via http://dx.doi.org/10.1038/ncb327
Extended Thromboprophylaxis with Betrixaban in Acutely Ill Medical Patients
Background
Patients with acute medical illnesses are at prolonged risk for venous thrombosis. However, the appropriate duration of thromboprophylaxis remains unknown.
Methods
Patients who were hospitalized for acute medical illnesses were randomly assigned to receive subcutaneous enoxaparin (at a dose of 40 mg once daily) for 10±4 days plus oral betrixaban placebo for 35 to 42 days or subcutaneous enoxaparin placebo for 10±4 days plus oral betrixaban (at a dose of 80 mg once daily) for 35 to 42 days. We performed sequential analyses in three prespecified, progressively inclusive cohorts: patients with an elevated d-dimer level (cohort 1), patients with an elevated d-dimer level or an age of at least 75 years (cohort 2), and all the enrolled patients (overall population cohort). The statistical analysis plan specified that if the between-group difference in any analysis in this sequence was not significant, the other analyses would be considered exploratory. The primary efficacy outcome was a composite of asymptomatic proximal deep-vein thrombosis and symptomatic venous thromboembolism. The principal safety outcome was major bleeding.
Results
A total of 7513 patients underwent randomization. In cohort 1, the primary efficacy outcome occurred in 6.9% of patients receiving betrixaban and 8.5% receiving enoxaparin (relative risk in the betrixaban group, 0.81; 95% confidence interval [CI], 0.65 to 1.00; P=0.054). The rates were 5.6% and 7.1%, respectively (relative risk, 0.80; 95% CI, 0.66 to 0.98; P=0.03) in cohort 2 and 5.3% and 7.0% (relative risk, 0.76; 95% CI, 0.63 to 0.92; P=0.006) in the overall population. (The last two analyses were considered to be exploratory owing to the result in cohort 1.) In the overall population, major bleeding occurred in 0.7% of the betrixaban group and 0.6% of the enoxaparin group (relative risk, 1.19; 95% CI, 0.67 to 2.12; P=0.55).
Conclusions
Among acutely ill medical patients with an elevated d-dimer level, there was no significant difference between extended-duration betrixaban and a standard regimen of enoxaparin in the prespecified primary efficacy outcome. However, prespecified exploratory analyses provided evidence suggesting a benefit for betrixaban in the two larger cohorts. (Funded by Portola Pharmaceuticals; APEX ClinicalTrials.gov number, NCT01583218. opens in new tab.
Notes on the Sex of the Gametophyte of Onoclea struthiopteris
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Iterative interference cancellation scheme with pilot-aided spacetime estimation in ds-cdma systems
Abstract: Iterative multiuser interference cancellation schemes for Direct Sequence Code Division Multiple Access systems exhibit good performance results for a reasonable complexity. We study an efficient iterative scheme, combining interference cancellation, soft input soft output decoding and beamforming. To deal with unknown channels, we add a pilot-aided space-time channel estimation in each iteration. The iterative structure has two advantages: the observation signal used for estimation contains less interference from one iteration to the following and soft estimates of coded bits are available for data-aided estimation
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