Performance Analysis of Anti-CW Interference in MC-CDMA Systems

The multicarrier-code division multiple access (MC-CDMA),which is the combination of direct sequence CDMA (DS-CDMA) and orthogonal frequency division multiplexing (OFDM) techniques, offers various advantages over single-carrier CDMA system. Some of the advantages are that MC-CDMA systems possess can remove the intersymbol interference (ISI) and enhance narrow-band interference suppression capabilities. So the MC-CDMA technique becomes a focus in the field of mobile communication. The authors introduce the typical MC-CDMA system model, discuss the decision statisticalvariable in Rayleigh fading channel included the CW interference, and give the expressions of probability of error in uplink. An approach is proposed with Modified Equal Gain Combining (MEGC) to decrease the effect of CW interference. Theoretical analysis and numerical results show that the anti-CW interference performance of MC-CDMA system can be improved used the MEGC approach.     

Hybridization and in vitro culture of an orchid hybrid Ascocenda ‘Kangla’

The present study focuses on hybridization program involving two species belonging to two different vandaceous genera, viz., Ascocentrum ampullaceum (Roxb.) Schltr. var. auranticum, a narrow endemic orchid of Manipur and Vanda coerulea Griff., an endangered orchid of Appendix I of CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora), to synthesize the primary hybrid genus with intermediate and improved characters in the F₁ generation. Observations on the crossability in the present bigeneric cross between V. coerulea and A. auranticum had been achieved with 60% success when V. coerulea was taken as female parent. Murashige and Skoog (MS) basal medium at half-strength was effective for the development of the hybrid seedlings of V. coerulea × A. auranticum followed by Vacin and Went (VW) and Knudson C (KC) media. The best response of seedling growth was observed on MS medium at half-strength supplemented with 2.3 μM kinetin + 0.5 μM α-naphthalene acetic acid with maximum shoot height (2.7 cm), leaf number (4.6) and root number (4.1) after 150 days of inoculation. The survival percentage and growth performance of the seedlings were found to be higher (80% survival) in potting substrate consisting of brick:charcoal in the ratio 2:1 mulched with moss (Sphagnum sp.) than in potting substrate consisting of brick:charcoal:tree fern in the ratio 2:1:1. The first flowering was observed in the hybrid seedlings of V. coerulea × A. auranticum after 2 years of transfer to the ex vitro environment. Morphologically, the flowers differed from that of the parents clearly showing the success of the hybridization experiment. Registration of the hybrid has been made with the Royal Horticultural Society with the nomenclature Ascocenda ‘Kangla’ (No. T128725).     

The effect of aqueous extract of gross and commercial yerba mate (Ilex paraguariensis) on intra-abdominal and epididymal fat and glucose levels in male Wistar rats

This study analyzed the plasma lipid profile, glucose levels and fat deposits in male rats treated with aqueous extract of gross yerba mate, commercial yerba mate or water. Yerba mate treatment did not change body weight gain and lipid profile. The consumption of gross yerba mate significantly increased blood glucose (6.6 mmol/L) as compared to the water (4.8 mmol/L) and commercial group (5.2 mmol/L) and decreased epididymal and intra-abdominal deposits (10.1 mg/g and 23.7 mg/g of weight) as compared to the water (15.4 mg/g and 36.9 mg/g of weight) and commercial group (12.5 mg/g and 28 mg/g of weight). The results suggest that gross yerba mate reduces fat more efficiently but produces a greater increase in blood glucose when compared to commercial yerba mate and water groups.     

添加白菜尾菜和甲酸对干玉米秸秆贮存品质的影响

基于干玉米秸秆与白菜尾菜的理化互补特性,详细研究了添加白菜尾菜对干秸秆贮存品质的影响,并进一步探讨添加甲酸对二者混贮品质的调控效果,结合高通量测序技术解析贮存过程中的微生物多样性。试验设置干秸秆单一贮存组(SE组)、干秸秆/白菜混贮组(ME组)和干秸秆/白菜混贮+甲酸组(FB组)3个试验组,(18±1)℃恒温密闭贮存60d,间隔30d分析有机组分含量、发酵品质及细菌多样性的动态变化。结果表明,ME和FB组的干物质损失率和pH值均显著低于对照SE组(P<0.05),长时间贮存有利于降低酸性洗涤木质素(ADL)含量。与SE组相比,ME和FB组乳酸细菌多样性更为丰富,包含乳杆菌属、类乳杆菌属、肉食杆菌属、乳球菌属、片球菌属、肠球菌属等。肠杆菌属是贮存过程中的主要腐败菌,但60d时FB组中肠杆菌属丰度明显低于SE组。可见,废弃白菜与干玉米秸秆进行混合湿法贮存能减少干物质损失,调控发酵微生物菌群结构,加入甲酸能进一步优化木质纤维组分。     

A floating threshold quantization algorithm to suppressmixing interferences in partial discharge

Due to the obvious difference of energy distribution frequencies from partial discharge (PD) signal and its mixing interferences (white noise and narrow brand), we uses the characteristic that node decomposition coefficients of wavelet packet transform can effectively show the energy change of signals to build up a floating threshold quantization algorithm (FTQA) varying with the noise energy of PD decomposition coefficients. It makes the node thresholds under the optimal base various with the noise strength in decomposition coefficients to self adaptively reality the choice of optimal threshold to finely partition PD decomposition coefficients. For simulated and real PD signals with mixing interferences, the conditional global threshold quantization algorithm (GTQA) and the proposed floating threshold quantization algorithm are employed to suppress the mixing interferences in PD signals and compared, and the results show that the proposed algorithm has the stronger suppression ability to mixing interference on PD signal and keeps perfect PD waveform via suppression.     

Micropropagation of Cymbidium Sleeping Nymph through protocorm-like bodies production by thin cell layer culture

Transverse thin cell layers (tTCLs) of protocorm-like bodies of two stages of PLBs (30 d and 60 d old) of Cymbidium Sleeping Nymph were used as explants to induce PLBs by using coconut water (CW) as a natural additive. 5% (v/v) CW supplemented to KC medium induced an average of 5 PLBs per responding tTCL of 30 d old PLBs with 83% of responding tTCLs. A low percentage of responding tTCLs were observed in 60 d old PLBs’ tTCLs. Anatomical and confocal microscopic studies traced the origin of PLBs to subepidermal layers of the tTCL. A significantly high percentage of shoot regeneration was obtained from PLBs formed on 1–10% (v/v) CW from tTCLs of 30 d old PLBs in comparison to PLBs induced on control after first subculture on KC medium (without CW). The induced PLBs regenerated into plantlets with velamenous roots and these plantlets were transferred to greenhouse conditions on cocopeat:perlite (9:1) with nearly 100% survival. Post-transfer performance of the plantlets was monitored. The results suggest tTCLs as potential explants (with respect to economy of precious hybrid materials) which can overcome the slow growth of hybrid PLBs and coconut water as a single natural additive for the mass multiplication of commercially important orchids.     

人为干扰对黄山高海拔木本植被生长的影响

对黄山高海拔景区黄山松、黄山杜鹃等8种代表性木本植被,以正向、逆向人为干扰情况下的相对生长量作为统计指标,建立和遴选了8个树种回归模型,模拟预测各树种在正向、逆向人为干扰时的受损过程和恢复过程。结果表明,四照花、三桠乌药、灯笼树3种树种耐逆向人为干扰能力较强,第5年时仍能保持至原生生长状态的51.71%～63.78%,正向人为干扰下恢复进程快,可恢复至原生生长状态的92.96%～100%。白檀、水榆花楸、六道木3种树种耐逆向人为干扰能力中等(42.92%～49.71%),但恢复能力却很强(96.56%～99.67%);黄山松、黄山杜鹃耐逆向人为干扰能力弱(38.89%～43.05%),恢复也很缓慢。     

Determination of total organic‐C in soils by an improved chromic acid digestion and spectrophotometric procedure

Abstract

An improvement to the Walkley‐Black wet digestion method for the rapid determination of organic carbon over the range 0.2–5.5% in air‐dry soil is described. It permits total recovery of the organic‐C in finely ground soil samples digested with the heat of dilution from mixing N K₂ Cr₂ O₇ with concentrated H₂SO₄. in test tubes followed by external heating from a hot‐plate digestor. The organic‐C concentrations are determined directly, as the Cr product in diluted soil digests, by absorptiometry at 600 nm with calibration against similarly treated sucrose standards in solution. For the soils tested, there were negligible interferences from carbonates, wood charcoal, coke, Fe⁺² and readily reducible Mn; Cl does not interfere with the organic‐C assay in non‐saline soils but for saline soils a correction based on 1/12 Cl^‐ assay of the soil is necessary. The present method is compared with Tabatabai and Bremner's dry combustion procedure and Allison's manometric adaptation for calcareous soils. The procedure described here does not require carbonate to be determined and is therefore simpler. In addition it is cheaper, faster and more effective in controlling interferences than dry combustion procedures.     

Fast abiotic sorption of selenates (SeO42-) in soils: pitfalls of batch sorption data acquired by inductively coupled plasma quadrupole mass spectrometry (ICP-QMS)

Low selenium (Se) dietary intake has encouraged the development of fortification strategies such as SeO₄^2- application to arable land. Selenate is highly mobile in soil systems, but it is not known whether fast abiotic retention could reduce Se loss from topsoil after SeO₄^2- fertilisation. This work explicitly aims at fast abiotic SeO₄^2- sorption in three soils exposed to 20–1250 µg L^?1 Se in a 24-h batch experiment. This study demonstrated the susceptibility of Se sorption data to distortion when inductively coupled plasma quadrupole mass spectrometry (ICP-QMS) measurements suffered from non-spectral interferences induced by concomitant elements in an aqueous soil-derived matrix. The distribution coefficient (K_d), not exceeding 2 L kg^?1 at any Se level, was shown to be a useful indicator for the extent of ion competition for sorption sites depending on the SeO₄^2- concentration employed. Sorption experiments conducted in the presence or absence of nitrate (10 mM), sulphate (0.52 mM) and phosphate (0.21 mM) allowed three phenomena explaining different SeO₄^2- retention behaviours found even between similar Cambisols to be proposed. Finally, we showed that the co-application of sulphate or phosphate with SeO₄^2- might decrease Se sorption from 150–170 µg kg^?1 to a net release from native Se pool.

Abbreviations: 1^st IP: first ionisation potential; RSD: relative standard deviation