Common black coatings - reflectance and ageing characteristics in the 0.32-14.3 mu m wavelength range

The diffuse and regular reflectances of five optically absorbing coatings frequently used in optical systems, were measured over the 0.32-14.3 mu m wavelength range, before and after exposure to heat and intense optical radiation. The measured coatings included Nextel Velvet Black, an anodised coating and NPL Super Black. The anodised coating exhibited substantial variations in its diffuse and regular reflectance values after thermal and simulated solar ageing. Solar and thermal ageing of the Nextel Velvet Black resulted in increases of its reflectance. However, thermal ageing tended to decrease the reflectance of the other paint samples examined. Thermal and solar ageing of the NPL Super Black resulted in only minor changes in its reflectance characteristics. All measurements are traceable to the UK National Standards.

Improved and optimal dual circular 32-QAM for MB-OFDM

Quadrature Phase Shift Keying (QPSK) and Dual Carrier Modulation (DCM) are currently used as the modulation schemes for Multiband Orthogonal Frequency Division Multiplexing (MB-OFDM) in the ECMA-368 defined Ultra-Wideband (UWB) radio platform. ECMA-368 has been chosen as the physical radio platform for many systems including Wireless USB (W-USB), Bluetooth 3.0 and Wireless HDMI; hence ECMA-368 is an important issue to consumer electronics and the users’ experience of these products. To enable the transport of high-rate USB, ECMA-368 offers up to 480 Mb/s instantaneous bit rate to the Medium Access Control (MAC) layer, but depending on radio channel conditions dropped packets unfortunately result in a lower throughput. This paper presents improvement on a high data rate modulation scheme that fits within the configuration of the current standard increasing system throughput by achieving 600 Mb/s (reliable to 3.2 meters) thus maintaining the high rate USB throughput even with a moderate level of dropped packets. The modulation system is termed improved and optimal Dual Circular 32-QAM (DC 32-QAM). The system performance for improved and optimal DC 32-QAM modulation is presented and compared with previous DC 32- QAM, 16-QAM and DCM.

Enhancing MB-OFDM throughput with dual circular 32-QAM

Quadrature Phase Shift Keying (QPSK) and Dual Carrier Modulation (DCM) are currently used as the modulation schemes for Multiband Orthogonal Frequency Division Multiplexing (MB-OFDM) in the ECMA-368 defined Ultra-Wideband (UWB) radio platform. ECMA-368 has been chosen as the physical radio platform for many systems including Wireless USB (W-USB), Bluetooth 3.0 and Wireless HDMI; hence ECMA-368 is an important issue to consumer electronics and the users experience of these products. To enable the transport of high-rate USB, ECMA-368 offers up to 480 Mb/s instantaneous bit rate to the Medium Access Control (MAC) layer, but depending on radio channel conditions dropped packets unfortunately result in a lower throughput. This paper presents an alternative high data rate modulation scheme that fits within the configuration of the current standard increasing system throughput by achieving 600 Mb/s (reliable to 3.1 meters) thus maintaining the high rate USB throughput even with a moderate level of dropped packets. The modulation system is termed Dual Circular 32-QAM (DC 32-QAM). The system performance for DC 32-QAM modulation is presented and compared with 16-QAM and DCM1.

Do variations in substitution rates and male mutation bias correlate with life-history traits? A study of 32 mammalian genomes

Life-history traits vary substantially across species, and have been demonstrated to affect substitution rates. We compute genomewide, branch-specific estimates of male mutation bias (the ratio of male-to-female mutation rates) across 32 mammalian genomes and study how these vary with life-history traits (generation time, metabolic rate, and sperm competition). We also investigate the influence of life-history traits on substitution rates at unconstrained sites across a wide phylogenetic range. We observe that increased generation time is the strongest predictor of variation in both substitution rates (for which it is a negative predictor) and male mutation bias (for which it is a positive predictor). Although less significant, we also observe that estimates of metabolic rate, reflecting replication-independent DNA damage and repair mechanisms, correlate negatively with autosomal substitution rates, and positively with male mutation bias. Finally, in contrast to expectations, we find no significant correlation between sperm competition and either autosomal substitution rates or male mutation bias. Our results support the important but frequently opposite effects of some, but not all, life history traits on substitution rates. KEY WORDS: Generation time, genome evolution, metabolic rate, sperm competition.

Effect of milk type and processing on iodine concentration of organic and conventional winter milk at retail: implications for nutrition

Milk is the largest source of iodine in UK diets and an earlier study showed that organic summer milk had significantly lower iodine concentration than conventional milk. There are no comparable studies with winter milk or the effect of milk fat class or heat processing method. Two retail studies with winter milk are reported. Study 1 showed no effect of fat class but organic milk was 32.2% lower in iodine than conventional milk (404 vs. 595 μg/L; P < 0.001). Study 2 found no difference between conventional and Channel Island milk but organic milk contained 35.5% less iodine than conventional milk (474 vs. 306 μg/L; P < 0.001). UHT and branded organic milk also had lower iodine concentrations than conventional milk (331 μg/L; P < 0.001 and 268 μg/L: P < 0.0001 respectively). The results indicate that replacement of conventional milk by organic or UHT milk will increase the risk of sub-optimal iodine status especially for pregnant/lactating women.