On the Implementation of Carrierless Amplitude and Phase Modulation in Visible Light Communication

OAPA Carrierless amplitude and phase modulation (CAP) is one of the spectrally efficient schemes that has been proposed to tackle the limited modulation bandwidth challenge in visible light communication (VLC). The VLC technology leverages existing lighting fixtures to provide wireless data communication, which makes it attractive for many applications. However, the commercially available white LEDs that are predominantly employed in VLC offer low modulation bandwidths that limit the achievable data rate. Thus, CAP modulation is employed to improve achievable data rate, primarily due to its implementation simplicity and high spectral efficiency. The CAP scheme also has a special feature in that it can be implemented as a single band or a multiband scheme which provides design flexibility. This paper presents an in-depth study of the implementation of CAP in LED-based VLC systems, highlighting the unique features that make it specially suited for VLC applications. Furthermore, a comprehensive investigation is carried out regarding the design parameters of the CAP modulation transceiver, its benefits and techniques to mitigate the challenges of CAP-based VLC systems

Case Report: Pneumomediastinum and Subcutaneous Emphysema Complicating Acute Exacerbation of Bronchial Asthma

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Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

Background Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide.Methods A multimethods analysis was performed as part of the GlobalSurg 3 study-a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital.Findings Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3.85 [95% CI 2.58-5.75]; p<0.0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63.0% vs 82.7%; OR 0.35 [0.23-0.53]; p<0.0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer.Interpretation Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised

Joint equalization and synchronization for carrierless amplitude and phase modulation in visible light communication

\ua9 2017 IEEE. In this paper, a linear adaptive least mean square (LMS) fractionally spaced equalizer (FSE) is proposed to jointly mitigate the severe inter-symbol interference (ISI) and timing jitter encountered by carrierless amplitude and phase modulation (CAP) in visible light communication (VLC) systems. The performance of FSE is compared to that of its counterpart, the symbol spaced equalizer (SSE), at the forward error control (FEC) bit error rate (BER) limit. It is shown that at a signal-to-noise ratio (SNR) of 20 dB and FEC BER limit of 3 7 10-3, FSE is able to achieve a bit rate of 95 Mb/s (spectral efficiency η of 14.6 bits/s/Hz) while only 30 Mb/s (η of 4.6 bits/s/Hz) is possible with SSE using CAP-64. It is observed that the FSE performance is insensitive to timing jitter while SSE performance suffers severe degradation. The results therefore indicate that FSE is better suited for CAP-based VLC systems than the widely used SSE

Autoimmune liver disease in a Nigerian woman

Autoimmune liver diseases are chronic liver disease with similar clinical features to viral and non-autoimmune liver disorders but with distinct sero-autoimmunologic features. In developed countries, it accounts for about 20% of all liver transplantations in the USA. Most studies on liver disease in Nigeria centred on viral or alcohol aetiology with complete absence of data on autoimmune liver disease

Modeling of magnetic cooling power of manganite-based materials using computational intelligence approach

Magnetic refrigeration (MR) technology has been identified as a potential replacement for the gas compression system of refrigeration due to its environmental friendliness and high level of efficiency. This technology utilizes manganite-based materials as magnetic refrigerants due to the dependence of magnetic properties as well as relative cooling power (RCP) of this class of materials on the concentration and nature of the dopants. Quantifying the effect of dopants on RCP of manganite-based materials requires a long experimental procedures and techniques that are costly and time-consuming. In order to circumvent these challenges, we propose a model, based on support vector regression (SVR), which quickly estimates the RCP of doped manganite-based materials with high level of accuracy using crystal lattice constants as descriptors. The accuracy and ease with which the proposed SVR-based model estimates RCP of doped manganite-based materials is very promising and effective in designing MR system of desired RCP