Multi-Sample Slippage Test for Ordered Observations

A multi-sample slippage test based on ordered observations has been given. The test statistic is based on the sum of ranks of the sample. The probability distribution of the test statistic has been worked out for small sample and it turns out to be chi-square distribution for large sample. The analytical procedure has been explained by a numerical example.     

Silver Sorption to Myxococcus xanthus Biomass

This paper deals with silver sorption to Myxococcus xanthus biomass. The dry biomass of this microorganism is shown to be a good sorbent for the recovery of silver present at low solution concentrations. Between initial silver concentrations of 2 and 0.05 mM, the percentage of accumulation ranges from 8.12% to 75% of the total silver present in the solution. Transmission electron microscopy study of M. xanthus wet biomass after silver accumulation shows the sorption within the extracellular polysaccharide, on the cell wall, and in the cytoplasm. The presence of silver deposits in the cytoplasm indicates that at least two mechanisms are involved in silver sorption by this bacterium biomass. First, silver was bound to the cell surface and extracellular polysaccharide, and second, a silver intracellular deposition process took place. The higher amount of silver deposits in the extracellular polysaccharide, present abundantly in M. xanthus cells, explains the capacity of this bacterium to bind silver efficiently. The results obtained indicate that the removal of silver by M. xanthus from the diluted solutions could be used in recycling this valuable metal. One interesting observation of this investigation is the crystalline form, possibly as chlorargyrite, in which the silver deposits are found in the M. xanthus cells.     

粘虫核型多角体病毒凋亡抑制基因的定位,序列和启动子结构

以ＡｃＮＰＶ凋亡抑制基因ｐ３５为探针,与ＬｓＮＰＶＤＮＡ的限制性片段和ＬｓＮＰＶＤＮＡＥｃｏＲＶ片段杂交,发现ＥｃｏＲＶ５．５ｋｂ片段有强烈的杂交信号。将此片段亚克隆后,测定了１２４４ｂｐ序列,发现一个完整的ＯＲＦ,推导的３０２个氨基酸与ＡｃＮＰＶｐ３５蛋白有７０．４％的氨基酸同源性,证明所测ＯＲＦ为ＬｓＮＰＶ的ｐ３５基因。结构分析发现其５′端有早期基因启动子元件ＧＣ、ＡＣＧＴ和ＴＡＴＡｂｏｘ。有２２ｂｐ的顺向重复序列,包括由两个重叠的ＴＡＴＡｂｏｘ和上下游两个ＡＣＧＴｍｏｔｉｆ组成的两套启动子元件,这些结构特征与ＡｃＮＰＶ的凋亡抑制基因十分相似。     

胃息肉与幽门螺杆菌感染关系研究

目的探讨胃息肉与幽门螺杆菌（Helicobacter pylori,H.pylori）感染关系。方法对1218例胃息肉同时进行H．pylori检查患者进行回顾性分析,分析胃息肉患者H.pylori感染率、胃息肉部位与H.pylori感染关系、胃息肉病理类型与H.pylori感染关系。结果发现胃息肉Hpylori感染患者532例,Hpylori感染率为43．7％。男性胃息肉患者H.pylori感染率为47．5％（216／455）,女性Hpriori感染率感染率为41．4％（316／763）（P〉0．05）,年龄〈20岁、20～39岁、40—59岁和≥60岁胃息肉H.priori感染率分别为41．7％、44．7％、41．6％和47．2％（P〉0．05）;胃窦胃角息肉H.pylori感染率高于其他部位（胃体、胃底和贲门）（P〈0．05）;炎性和增生性胃息肉H.priori感染率高于胃底腺和腺瘤性息肉（P〈0．05）。结论H.pylori感染可能与部分胃息肉发生有一定关系,需要进一步深入研究胃息肉的发生机制。     

Effects of species and habitat positional errors on the performance and interpretation of species distribution models

Aim A key assumption in species distribution modelling is that both species and environmental data layers contain no positional errors, yet this will rarely be true. This study assesses the effect of introduced positional errors on the performance and interpretation of species distribution models. Location Baixo Alentejo region of Portugal. Methods Data on steppe bird occurrence were collected using a random stratified sampling design on a 1‐km² pixel grid. Environmental data were sourced from satellite imagery and digital maps. Error was deliberately introduced into the species data as shifts in a random direction of 0–1, 2–3, 4–5 and 0–5 pixels. Whole habitat layers were shifted by 1 pixel to cause mis‐registration, and the cumulative effect of one to three shifted layers investigated. Distribution models were built for three species using three algorithms with three replicates. Test models were compared with controls without errors. Results Positional errors in the species data led to a drop in model performance (larger errors having larger effects – typically up to 10% drop in area under the curve on average), although not enough for models to be rejected. Model interpretation was more severely affected with inconsistencies in the contributing variables. Errors in the habitat layers had similar although lesser effects. Main conclusions Models with species positional errors are hard to detect, often statistically good, ecologically plausible and useful for prediction, but interpreting them is dangerous. Mis‐registered habitat layers produce smaller effects probably because shifting entire layers does not break down the correlation structure to the same extent as random shifts in individual species observations. Spatial autocorrelation in the habitat layers may protect against species positional errors to some extent but the relationship is complex and requires further work. The key recommendation must be that positional errors should be minimised through careful field design and data processing.     

Improved cattle behaviour monitoring by combining Ultra-Wideband location and accelerometer data

Cattle behaviour is fundamentally linked to the cows’ health, (re)production, and welfare. The aim of this study was to present an efficient method to incorporate Ultra-Wideband (UWB) indoor location and accelerometer data for improved cattle behaviour monitoring systems. In total, 30 dairy cows were fitted with UWB Pozyx wearable tracking tags (Pozyx, Ghent, Belgium) on the upper (dorsal) side of the cow’s neck. In addition to the location data, the Pozyx tag reports accelerometer data as well. The combination of both sensor data was performed in two steps. In the first step, the actual time spent in the different barn areas was calculated using location data. In the second step, accelerometer data were used to classify cow behaviour using the location information of step 1 (e.g., a cow located in the cubicles cannot be classified as feeding, or drinking). A total of 156 hours of video recordings were used for the validation. For each hour of data, the total time each cow spent in each area and performing which behaviours (feeding, drinking, ruminating, resting, and eating concentrates) were computed using the sensors and compared against annotated video recordings. Bland-Altman plots for the correlation and difference between the sensors and the video recording were then computed for the performance analysis. The overall performance of locating the animals into the correct functional areas was very high. The R² was 0.99 (P < 0.001), and the root-mean-square error (RMSE) was 1.4 min (7.5% of the total time). The best performance was obtained for the feeding and lying areas (R² = 0.99, P < 0.001). Performance was lower in the drinking area (R² = 0.90, P < 0.01) and the concentrate feeder (R² = 0.85, P < 0.05). For the combined location + accelerometer data, high overall performance (all behaviours) was obtained with an R² of 0.99 (P < 0.001) and a RMSE of 1.6 min (12% of the total time). The combination of location and accelerometer data improved the RMSE of the feeding time and ruminating time compared to the accelerometer data alone (2.6–1.4 min). Moreover, the combination of location and accelerometer enabled accurate classification of additional behaviours that are difficult to detect using the accelerometer alone, such as eating concentrates and drinking (R² = 0.85 and 0.90, respectively). This study demonstrates the potential of combining accelerometer and UWB location data for the design of a robust monitoring system for dairy cattle.     

The Intramitochondrial Localization of Superoxide Dismutase from Hypocotyl of Etiolated Soybean Seedlings

In the KCN inhibition experiment, it was found that superoxide dismutase from the hypo- cotyl of etiolated soybean seedlings which is composed of 88% Mn-SOD and 12% Cu-Zn-SOD. Latent activity of SOD was evidently liberated after the mitochondria were treated by supersonication. Most of SOD activity was present in supernatant fraction after the supersonicated mitochondria were centrifuged at 150000 g for 60 min. The method of separation and praparation of sub-mitochondrial fraction is described in this paper, and the results indicate that the 80% of mitochondrial SOD present in mitochondrial matrix fraction and a small amount SOD (16%) present in the mitochondrial intermembrane space. The results indicate that distribution and localization of intramitochondrial SOD from higher plant tissues are similar to that from animal tissues.     

蛋白质亚叶绿体和亚线粒体定位预测研究进展

蛋白质合成后被转运到特定的细胞器中,只有转运到正确的部位才能参与细胞的各种生命活动,有效地发挥功能,因此蛋白质的功能与其亚细胞定位有着密切的联系,通过确定蛋白质在细胞中的位置可以获取蛋白质功能和结构的信息。在近二十年中,蛋白质亚细胞定位预测算法研究已经取得很大的成绩,在此基础上,蛋白质在细胞器内亚结构的定位预测研究,如对蛋白质亚线粒体和亚叶绿体定位的研究成为更深层次的问题,本文简要介绍国内外在蛋白质亚叶绿体和亚线粒体定位预测方面的研究进展。