3,070 research outputs found

    Quasi-Dynamic Frame Coordination For Ultra- Reliability and Low-Latency in 5G TDD Systems

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    The fifth generation (5G) mobile technology features the ultra-reliable and low-latency communications (URLLC) as a major service class. URLLC applications demand a tight radio latency with extreme link reliability. In 5G dynamic time division duplexing (TDD) systems, URLLC requirements become further challenging to achieve due to the severe and fast-varying cross link interference (CLI) and the switching time of the radio frame configurations (RFCs). In this work, we propose a quasi-dynamic inter-cell frame coordination algorithm using hybrid frame design and a cyclic-offset-based RFC code-book. The proposed solution adaptively updates the RFCs in time such that both the average CLI and the user-centric radio latency are minimized. Compared to state-of-the-art dynamic TDD studies, the proposed scheme shows a significant improvement in the URLLC outage latency, i.e., 92% reduction gain, while boosting the cell-edge capacity by 189% and with a greatly reduced coordination overhead space, limited to B-bit

    Matter-positronium interaction: An exact diagonalization study of the He atom - positronium system

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    The many-body system comprising a He nucleus, three electrons, and a positron has been studied using the exact diagonalization technique. The purpose has been to clarify to which extent the system can be considered as a distinguishable positronium (Ps) atom interacting with a He atom and, thereby, to pave the way to a practical atomistic modeling of Ps states and annihilation in matter. The maximum value of the distance between the positron and the nucleus is constrained and the Ps atom at different distances from the nucleus is identified from the electron and positron densities, as well as from the electron-positron distance and center-of-mass distributions. The polarization of the Ps atom increases as its distance from the nucleus decreases. A depletion of the He electron density, particularly large at low density values, has been observed. The ortho-Ps pick-off annihilation rate calculated as the overlap of the positron and the free He electron densities has to be corrected for the observed depletion, specially at large pores/voids.Comment: 18 pages, 8 figure

    Functional status in ICU survivors and out of hospital outcomes: a cohort study

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    OBJECTIVES: Functional status at hospital discharge may be a risk factor for adverse events among survivors of critical illness. We sought to examine the association between functional status at hospital discharge in survivors of critical care and risk of 90-day all-cause mortality after hospital discharge. DESIGN: Single-center retrospective cohort study. SETTING: Academic Medical Center. PATIENTS: Ten thousand three hundred forty-three adults who received critical care from 1997 to 2011 and survived hospitalization. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The exposure of interest was functional status determined at hospital discharge by a licensed physical therapist and rated based on qualitative categories adapted from the Functional Independence Measure. The main outcome was 90-day post hospital discharge all-cause mortality. A categorical risk-prediction score was derived and validated based on a logistic regression model of the function grades for each assessment. In an adjusted logistic regression model, the lowest quartile of functional status at hospital discharge was associated with an increased odds of 90-day postdischarge mortality compared with patients with independent functional status (odds ratio, 7.63 [95% CI, 3.83-15.22; p < 0.001]). In patients who had at least 7 days of physical therapy treatment prior to hospital discharge (n = 2,293), the adjusted odds of 90-day postdischarge mortality in patients with marked improvement in functional status at discharge was 64% less than patients with no change in functional status (odds ratio, 0.36 [95% CI, 0.24-0.53]; p < 0.001). CONCLUSIONS: Lower functional status at hospital discharge in survivors of critical illness is associated with increased postdischarge mortality. Furthermore, patients whose functional status improves before discharge have decreased odds of postdischarge mortality.L30 TR001257 - NCATS NIH HH

    A novel lozenge containing bupivacaine as topical alleviation of oral mucositis pain in patients with head and neck cancer:a pilot study

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    Abstract. Introduction: Oral mucositis induces severe oral pain in head and neck cancer patients. There is at this point no effective pain treatment without considerable side effects. Objective: The aim of this pilot study was to investigate pain reduction in oral cavity and pharynx in patients with head and neck cancer (HNC) with oral mucositis, the location of anesthetic effect, and duration of pain relief, after a single-dose administration of a 25 mg bupivacaine lozenge. Methods: Ten patients with HNC suffering from oral mucositis pain were included. The patients assessed pain in the oral cavity and pharynx on a visual analogue scale (from 0 to 100 mm) at baseline and up to 3 hours after the lozenge was dissolved. Possible adverse events were registered. Results: The baseline pain was 51 mm (range: 30–73 mm) in the oral cavity and 58 mm (range: 35–70 mm) in the pharynx. When the lozenge was dissolved, both oral (−27 mm; range: −3 to −52 mm; P = 0.0003) and pharynx pain (−20 mm; range: −3 to −45 mm; P = 0.008) were significantly reduced. After 180 minutes, the mean reduction in pain was significant in the oral cavity (−18 mm; range: −8 to −30 mm; P < 0.0001) but not in the pharynx (−8 mm; range: +4 to −23 mm; P = 0.12). No adverse events were observed. Conclusion: The results indicate that the bupivacaine lozenge has a clinically significant and long-lasting pain-relieving effect on pain because of oral mucositis in patients with HNC

    Overcoming laser diode nonlinearity issues in multi-channel radio-over-fiber systems

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    The authors demonstrate how external light injection into a directly modulated laser diode may be used to enhance the performance of a multi-channel radio-over-fiber system operating at a frequency of 6 GHz. Performance improvements of up to 2 dB were achieved by linearisation of the lasers-modulation response. To verify the experimental work a simulation of the complete system was carried out using Matlab. Good correlation was observed between experimental and simulated results

    Impact of the sea surface temperature forcing on hindcasts of Madden-Julian Oscillation events using the ECMWF model

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    This paper explores the sensitivity of hindcasts of the Madden Julian Oscillation (MJO) to the use of different sea surface temperture (SST) products as lower boundary conditions in the European Centre for Medium-range Weather Forecasts (ECMWF) atmospheric model. Three sets of monthly hindcast experiments are conducted, starting from initial conditions from the ERA interim reanalysis. First, as a reference, the atmosphere is forced by the SST used to produce ERA interim. In the second and third experiments, the SST is switched to the OSTIA (Operational Sea Surface Temperature and Sea-Ice Analysis) and the AVHRR-only (Advanced Very High Resolution Radiometer) reanalyses, respectively. Tests on the temporal resolution of the SST show that monthly fields are not optimal, while weekly and daily resolutions provide similar MJO scores. When using either OSTIA or AVHRR, the propagation of the MJO is degraded and the resulting scores are lower than in the reference experiment. Further experiments show that this loss of skill cannot be attributed to either the difference in mean state or temporal variability between the SST products. Additional diagnostics show that the phase relationship between either OSTIA or AVHRR SST and the MJO convection is distorted with respect to satellite observations and the ERA interim reanalysis. This distortion is expected to impact the MJO hindcasts, leading to a relative loss of forecast skill. A realistic representation of ocean–atmosphere interactions is thus needed for MJO hindcasts, but not all SST products – though accurate for other purposes – fulfill this requirement
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