Sources of Cadaver for Anatomic Sciences in an Evolving Medical Institution

The concept of dissecting human body revolutionized Anatomy as a sacred discipline. Evaluating sources of cadaver adds values to care of human remains with due respect to body donors for their magnanimous and selfless act in furtherance of medical education and research. This study aimed at bridging communication gap in getting the rightful cadavers for anatomic education with specific objectives addressing the challenges involved. The department’s Cadaver Registry contained: date and source of cadaver, gender, race, likely age, cause of death, autopsy report, type of embalmment, mode of release, financial expenditure and mode of disposal. Data were subjected to simple statistical analysis while Kendall’s Coefficient of Concordance was adopted for test of significance. Forty-one adult cadavers procured from five mortuaries were analysed with male to female ratio of 13 to 1 while student to cadaver ratio was 5 to 1. Unclaimed body dominated cause of death with 68.3% while the rest was armed-robbery. Autopsy was earlier performed on 9.8% of cadaver before acquisition. Undisclosed payment transpired on 80.5% before release from provincial mortuaries. Tests of significance amongst the characteristics were statistically-significant proven the itemized factors to be independent. Elucidative programmes were identified in checking the strong socio-cultural heritage against whole body bequeaths to acquire rightful cadavers. Main sources were from unclaimed body and legally executed criminals. Gender and student to cadaver ratios were promising for anatomic utilization. The proposed amendment on old anatomic act in Nigeria should be sagely incorporated with whole body bequeath affairs

Coherent optical binary polarisation shift keying heterodyne system in the free-space optical turbulence channel

In this paper, analytical and simulation results for the bit error rate (BER) performance and fading penalty of a coherent optical binary polarization shift keying (2PolSK) heterodyne system adopted for a free space optical (FSO) communication link modeled as the log-normal and the negative exponential atmospheric turbulence channels are presented. The conditional and unconditional BER expressions are derived, demonstrating the comprehensive similarity between the 2PolSK and the binary frequency shift keying (2FSK) schemes with regards to the system sensitivity. The power penalty due to the non-ideal polarization beam splitter (PBS) is also analyzed. The receiver sensitivity employing 2PolSK is compared with other modulation schemes in the presence of turbulence and the phase noise. The results show that 2PolSK offers improved signal-to-noise ratio (SNR) performance compared to the binary amplitude shift keying (2ASK)

Free-space optical communication employing subcarrier modulation and spatial diversity in atmospheric turbulence channel

An expression for the bit error rate of a multiple subcarrier intensity-modulated atmospheric optical communication system employing spatial diversity is derived. Spatial diversity is used to mitigate scintillation caused by atmospheric turbulence, which is assumed to obey lognormal distribution. Optimal but complex maximum ratio, equal gain combining (EGC) and relatively simple selection combining spatial diversity techniques in a clear atmosphere are considered. Each subcarrier is modulated using binary phase shift keying. Laser irradiance is subsequently modulated by a subcarrier signal, and a direct detection PIN receiver is employed (i.e. intensity modulation/direction detection). At a subcarrier level, coherent demodulation is used to extract the transmitted data/information. The performance of on–off-keying is also presented and compared with the subcarrier intensity modulation under the same atmospheric conditions

MIMO free-space optical communication employing subcarrier intensity modulation in atmospheric turbulence channels

In this paper, we analyse the error performance of transmitter/receiver array free-space optical (FSO) communication system employing binary phase shift keying (BPSK) subcarrier intensity modulation (SIM) in clear but turbulent atmospheric channel. Subcarrier modulation is employed to eliminate the need for adaptive threshold detector. Direct detection is employed at the receiver and each subcarrier is subsequently demodulated coherently. The effect of irradiance fading is mitigated with an array of lasers and photodetectors. The received signals are linearly combined using the optimal maximum ratio combining (MRC), the equal gain combining (EGC) and the selection combining (SelC). The bit error rate (BER) equations are derived considering additive white Gaussian noise and log normal intensity fluctuations. This work is part of the EU COST actions and EU projects

A 10 Mb/s visible light communication system using a low bandwidth polymer light-emitting diode

In this paper we experimentally demonstrate a 10 Mb/s error free visible light communications (VLC) system using polymer light-emitting diodes (PLEDs) for the first time. The PLED under test is a blue emitter with ∼600 kHz bandwidth. Having such a low bandwidth means the introduction of an intersymbol interference (ISI) induced penalty at higher transmission speeds and thus the requirement for an equalizer. In this work we improve on previous literature by implementing a decision feedback equalizer, rather than a linear equalizer. Considering 7% and 20% forward error correction codes, transmission speeds up to ∼12 Mb/s can be supported

10 Mb/s visible light transmission system using a polymer light-emitting diode with orthogonal frequency division multiplexing

We present a newly designed polymer light-emitting diode with a bandwidth of ∼350 kHz for high-speed visible light communications. Using this new polymer light-emitting diode as a transmitter, we have achieved a record transmission speed of 10 Mb/s for a polymer light-emitting diode-based optical communication system with an orthogonal frequency division multiplexing technique, matching the performance of single carrier formats using multitap equalization. For achieving such a high data-rate, a power pre-emphasis technique was adopted

Performance of quadrature amplitude modulation orthogonal frequency division multiplexing-based free space optical links with non-linear clipping effect over gamma-gamma modelled turbulence channels

The free space optical (FSO) communication systems have attracted significant research and commercial interest in the last few years because of their low installation and operational cost along with their very high performance characteristics. However, for terrestrial FSO links, the optical signal propagates through the atmosphere which exhibits time-varying behaviour that implies variations in the links' performance. In this study, the authors estimate the performance metrics for terrestrial FSO links which are using the orthogonal frequency division multiplexing (OFDM) technique with a quadrature amplitude modulation scheme over turbulence channels. More specifically, the authors investigate the influence of the non-linear clipping effect of the OFDM scheme, along with the atmospheric turbulence modelled using the gamma-gamma distribution. Both effects significantly influence the performance of the link and here the authors derive closed form mathematical expressions for the estimation of the average signal to noise ratio, the outage probability and the average bit error rate that are vital for FSO system performance characterisation. Finally, using these expressions, the authors present the corresponding numerical results for common parameter values of the FSO links and investigate the accuracy of the expressions for marginal cases with nearly negligible turbulence effect. © 2015 The Institution of Engineering and Technology