Balance functions from Au+Au, d+Au, and p+p collisions at root s(NN)=200 GeV

Balance functions have been measured for charged-particle pairs, identified charged-pion pairs, and identified charged-kaon pairs in Au + Au, d + Au, and p + p collisions at root s(NN) = 200 GeV at the Relativistic Heavy Ion Collider using the STAR detector. These balance functions are presented in terms of relative pseudorapidity, Delta eta, relative rapidity, Delta y, relative azimuthal angle, Delta phi, and invariant relative momentum, q(inv). For charged-particle pairs, the width of the balance function in terms of Delta eta scales smoothly with the number of participating nucleons, while HIJING and UrQMD model calculations show no dependence on centrality or system size. For charged-particle and charged-pion pairs, the balance functions widths in terms of Delta eta and Delta y are narrower in central Au + Au collisions than in peripheral collisions. The width for central collisions is consistent with thermal blast-wave models where the balancing charges are highly correlated in coordinate space at breakup. This strong correlation might be explained by either delayed hadronization or limited diffusion during the reaction. Furthermore, the narrowing trend is consistent with the lower kinetic temperatures inherent to more central collisions. In contrast, the width of the balance function for charged-kaon pairs in terms of Delta y shows little centrality dependence, which may signal a different production mechanism for kaons. The widths of the balance functions for charged pions and kaons in terms of q(inv) narrow in central collisions compared to peripheral collisions, which may be driven by the change in the kinetic temperature.

Longitudinal scaling property of the charge balance function in Au plus Au collisions at root s(NN)=200 GeV

We present measurements of the charge balance function, from the charged particles, for diverse pseudorapidity and transverse momentum ranges in Au + Au collisions at root S-NN = 200 GeV using the STAR detector at RHIC. We observe that the balance function is boost-invariant within the pseudorapidity coverage vertical bar-1.3, 1.3 vertical bar. The balance function properly scaled by the width of the observed pseudorapidity window does not depend on the position or size of the pseudorapidity window. This scaling property also holds for particles in different transverse momentum ranges. In addition, we find that the width of the balance function decreases monotonically with increasing transverse momentum for all centrality classes. (c) 2010 Elsevier B.V. All rights reserved.

Hemizygosity for Atm and Brca1 influence the balance between cell transformation and apoptosis

Background: In recent years data from both mouse models and human tumors suggest that loss of one allele of genes involved in DNA repair pathways may play a central role in genomic instability and carcinogenesis. Additionally several examples in mouse models confirmed that loss of one allele of two functionally related genes may have an additive effect on tumor development. To understand some of the mechanisms involved, we examined the role of monoallelic loss or Atm and Brca1 on cell transformation and apoptosis induced by radiation. Methods: Cell transformation and apoptosis were measured in mouse embryo fibroblasts (MEF) and thymocytes respectively. Combinations of wild type and hemizygous genotypes for ATM and BRCA1 were tested in various comparisons. Results: Haploinsufficiency of either ATM or BRCA1 resulted in an increase in the incidence of radiation-induced transformation of MEF and a corresponding decrease in the proportion of thymocytes dying an apoptotic death, compared with cells from wild-type animals. Combined haploinsufficiency for both genes resulted in an even larger effect on apoptosis. Conclusions: Under stress, the efficiency and capacity for DNA repair mediated by the ATM/BRCA1 cell signalling network depends on the expression levels of both proteins.

Changes in nutrient structure of river-dominated coastal waters: stoichiometric nutrient balance and its consequences

We present an analysis of extensive nutrient data sets from two river-dominated coastal ecosystems, the northern Adriatic Sea and the northern Gulf of Mexico, demonstrating significant changes in surface nutrient ratios over a period of 30 years. The silicon:nitrogen ratios have decreased, indicating increased potential for silicon limitation. The nitrogen:phosphorus and the silicon:phosphorus ratios have also changed substantially, and the coastal nutrient structures have become more balanced and potentially less limiting for phytoplankton growth. It is likely that net phytoplankton productivity increased under these conditions and was accompanied by increasing bottom water hypoxia and major changes in community species composition. These findings support the hypothesis that increasing coastal eutrophication to date may be associated with stoichiometric nutrient balance, due to increasing potential for silicon limitation and decreasing potential for nitrogen and phosphorus limitation. On a worldwide basis, coastal ecosystems adjacent to rivers influenced by anthropogenic nutrient loads may experience similar alterations.

Coastal metabolism and the oceanic organic carbon balance

Net organic metabolism (that is, the difference between primary production and respiration of organic matter) in the coastal ocean may be a significant term in the oceanic carbon budget. Historical change in the rate of this net metabolism determines the importance of the coastal ocean relative to anthropogenic perturbations of the global carbon cycle. Consideration of long-term rates of river loading of organic carbon, organic burial, chemical reactivity of land-derived organic matter, and rates of community metabolism in the coastal zone leads us to estimate that the coastal zone oxidizes about 7 × 1012 moles C/yr. The open ocean is apparently also a site of net organic oxidation (∼16 × 1012 moles C/yr). Thus organic metabolism in the ocean appears to be a source of CO2 release to the atmosphere rather than being a sink for atmospheric carbon dioxide. The small area of the coastal ocean accounts for about 30% of the net oceanic oxidation. Oxidation in the coastal zone (especially in bays and estuaries) takes on particular importance, because the input rate is likely to have been altered substantially by human activities on land.

黄土高原土壤水资源与植树造林

论文在对黄土高原土壤水分资源的赋存条件和土壤水分循环与平衡分析基础上， 讨论了人工林系统的土壤水文效应、 土壤干燥化──土壤干层的形成与植树造林问题。

Dynamic changes of total bacteria and Vibrio in an integrated seaweed-abalone culture system

Polyculture of seaweeds alongside fed animal aquaculture is an environmentally friendly means of avoiding eutrophication problem both in land-based and sea-based monoculture systems. Many aspects of such polyculture systems have been described, but little attention has been given to the impact of live seaweeds on the microbiological properties of the water that connects the algae and animals. In this investigation, the Pacific red alga Gracilaria textorii was cultured in a recirculated dual tank system (150 L) with the juvenile abalone Haliotis discus hannai. Dynamic changes of total bacteria (TB) and total Vibrio (TV) in the water of polyculture and monoculture systems were evaluated. Results revealed that (1) level of TB in the polyculture was constantly higher than in the monoculture over a 6.5-day period. While levels of TV in the polyculture was detected to be constantly lower than in the monoculture, (2) integration of G. textorii in the abalone culture changed the Vibrio compositions in the water as judged by the changes of bacteria colony types; (3) application of artificial diet led to dramatic increase of the levels in TB and TV in both systems at 12 h after application in the 24-h test and resulted in selective propagation of Vibrio in the water in the monoculture system; (4) polyculture of G. textorii with juvenile abalone in combination with feeding with live algal diet helped to maintain low levels of TV and the balance of the Vibrio composition; (5) living biomass of G. textorii was effective in preventing propagation of two purified Vibrio strains (V alginolaticus and V logei) in the water. These results provide a general basis of the dynamic changes of levels in TB and TV in a seaweed-abalone polyculture system with or without artificial diet in tanks. (c) 2005 Elsevier B.V All rights reserved.

Evaluation of a combined wavelet and a combined principal component analysis classification system for BCG diagnostic problem

Heart disease is one of the main factor causing death in the developed countries. Over several decades, variety of electronic and computer technology have been developed to assist clinical practices for cardiac performance monitoring and heart disease diagnosis. Among these methods, Ballistocardiography (BCG) has an interesting feature that no electrodes are needed to be attached to the body during the measurement. Thus, it is provides a potential application to asses the patients heart condition in the home. In this paper, a comparison is made for two neural networks based BCG signal classification models. One system uses a principal component analysis (PCA) method, and the other a discrete wavelet transform, to reduce the input dimensionality. It is indicated that the combined wavelet transform and neural network has a more reliable performance than the combined PCA and neural network system. Moreover, the wavelet transform requires no prior knowledge of the statistical distribution of data samples and the computation complexity and training time are reduced.

三种海水经济鱼类早期发育生物学的研究

海水经济鱼类的养殖在我国已经形成第四次海水养殖浪潮，经济效益显著，有力地推动了我国海水养殖的产业结构调整和可持续发展。然而在海水养殖发展过程中也存在着诸多问题，尤其是早期发育阶段的高死亡率，严重制约了我国海水养殖产业的稳定和健康发展。 海水鱼类养殖的关键为高质量，高存活率苗种的生产和培育，由于鱼类种类繁多，生物多样性丰富，对应实际的繁育技术，尤其是新品种的开发，必须要做出相应的调整。这就要求我们必须对每一种鱼类早期发育有所了解，并将形态和组织上的数据用于指导生产。 本文通过显微观察和组织学研究，主要描述和研究了我国北方三种重要的海水经济鱼类(条斑星鲽、杂交鲆、条石鲷)的早期发育生物学，并结合实际生产进一步阐明关键期的产生原因，机理以及采用相应的对策。具体结果如下： 1.条斑星鲽：作为冷温性鲆鲽鱼类，条斑星鲽早期发育过程的特征主要有： ① 条斑星鲽受精卵无油球，卵子呈半浮性；不同步卵裂现象提前，发生在第三次卵裂；卵裂期裂球大小差异大。孵化过程较长，在水温8 ± 0.3℃，盐度33的条件下，经9 d孵化。条斑星鲽胚胎发育的不同时期对温度的敏感性不同，其中原肠期对温度比较敏感。 ②在8-10℃，盐度33的条件下，8-9 dph开口摄食。且开口时，其吻前端出现有一点状黑褐色素，构成了条斑星鲽仔鱼“开口期”的重要标志。卵黄囊于消失。在后期仔鱼末期，背鳍和臀鳍上形成特有的黑褐色条斑带。 ③杯状细胞首先出现在咽腔后部和食道前段，胃腺和幽门盲囊出现于29 dph，变态期始于30dph。在条斑星鲽早期发育过程中，观察到其直肠粘膜层细胞质出现大量嗜伊红颗粒，为仔鱼肠道上皮吸收的蛋白质。 ④首先淋巴化的免疫器官是头肾，然后是胸腺和脾脏，这与大部分硬骨鱼类不同。条斑星鲽除头肾和脾脏外，胸腺实质也形成MMCs。其中以脾脏形成MMCs最为丰富，形态多样。 2. 杂交鲆：为同属的牙鲆和夏鲆间的远缘杂交种，其发育过程的特点为： ① 在温度为15.4～16.0℃，杂交鲆胚胎从受精到孵化所需的时间为76 h左右，胚孔关闭前期，胚胎先出现视囊及克氏囊，而后形成体节。孵出前胚体在卵膜内环绕不到1周。 ② 孵化后消失。杂交鲆群体变态间隔长(34-60 dph)，且变态高峰期出现的冠状幼鳍不明显(与母本牙鲆相比)，数量为7-8根。 ③组织学观察发现，其消化系统中胃腺出现较晚，且胃腺发育过程缓慢(与母本牙鲆相比)。甲状腺滤泡增生不明显，颜色较浅，数量较少。杂交鲆在早期发育过程中，并没有出现鳔原基。 3. 条石鲷作为岩礁性的暖水性鱼类，早期发育过程也较为特殊，包括外形以及内部的器官结构。主要特点有： ① 受精卵：受精卵卵黄上具有龟裂结构，为鱼卵的分类特征之一。 ② 初孵仔鱼：初孵仔鱼背鳍膜上的黑色素，从体背面向背鳍膜边缘移动，到3dph仔鱼基本消失，此为本种仔鱼发育所特有的特点。 ③ 后期仔鱼和稚鱼：肠道肌肉层加厚明显，仔稚鱼胃肠排空率急剧上升，死亡率增加，通过改善常规的投饵方式部分解决了这个死亡高峰的问题。在幼鱼初期，牙齿融合为骨喙，为石鲷科鱼类的特征。 ④胸腺上皮分泌细胞：类似的现象同样在虹鳟鱼中发现，但是虹鳟鱼胸腺上皮分泌细胞不如条石鲷的丰富，同样也不如条石鲷的排列整齐，而是零星分布在胸腺上皮与咽腔接触的表面。除了正常的造血器官—脾脏和头肾外，肝脏、胰腺和鳔等多种组织等也出现MMCs，此现象在硬骨鱼类不多见，一般发生在软骨鱼类。

Summer diet of two sympatric species of raptors Upland Buzzard (Buteo hemilasius) and Eurasian Eagle Owl (Bubo bubo) in alpine meadow: problem of coexistence

Summer diets of two sympatric raptors Upland Buzzards (Buteo hemilasius Temminck et Schlegel) and Eurasian Eagle Owls (Bubo bubo L. subsp. Hemachalana Hume) were studied in an alpine meadow (3250 m a.s.l.) on Qinghai-Tibet Plateau, China. Root voles Microtus oeconomus Pallas, plateau pikas Ochotona curzoniae Hodgson, Gansu pikas O. cansus Lyon and plateau zokors Myospalax baileyi Thomas were the main diet components of Upland Buzzards as identified through the pellets analysis with the frequency of 57, 20, 19 and 4%, respectively. The four rodent species also were the main diet components of Eurasian Eagle Owls basing on the pellets and prey leftovers analysis with the frequency of 53, 26, 13 and 5%, respectively. The food niche breadth indexes of Upland Buzzards and Eurasian Eagle Owls were 1.60 and 1.77 respectively (higher value of the index means the food niche of the raptor is broader), and the diet overlap index of the two raptors was larger (C-ue = 0.90) (the index range from 0 - no overlap - to I - complete overlap). It means that the diets of Upland Buzzards and Eurasian Eagle Owls were similar (Two Related Samples Test, Z = -0.752, P = 0.452). The classical resource partitioning theory can not explain the coexistence of Upland Buzzards and Eurasian Eagle Owls in alpine meadows of Qinghai-Tibet Plateau. However, differences in body size, predation mode and activity rhythm between Upland Buzzards and Eurasian Eagle Owls may explain the coexistence of these two sympatric raptors.

Depression of net ecosystem CO2 exchange in semi-arid Leymus chinensis steppe and alpine shrub

Uptake and release of carbon in grassland ecosystems is very critical to the global carbon balance and carbon storage. In this study, the dynamics of net ecosystem CO2 exchange (FNEE) of two grassland ecosystems were observed continuously using the eddy covariance technique during the growing season of 2003. One is the alpine shrub on the Tibet Plateau, and the other is the sem-arid Leymus chinensis steppe in Inner Mongolia of China. It was found that the FNEE of both ecosystems was significantly depressed under high solar radiation. Comprehensive analysis indicates that the depression of FNEE in the L. chinensis steppe was the results of decreased plant photosynthesis and increased ecosystem respiration (R-eco) under high temperature. Soil water stress in addition to the high atmospheric demand under the strong radiation was the primary factor limiting the stomatal conductance. In contrast, the depression of FNEE in the alpine shrub was closely related to the effects of temperature on both photosynthesis and ecosystem respiration, coupled with the reduction of plant photosynthesis due to partial stomatal closure under high temperature at mid-day. The R,c of the alpine shrub was sensitive to soil temperature during high turbulence (u* > 0.2 m s(-1)) but its FNEE decreased markedly when the temperature was higher than the optimal value of about 12 degrees C. Such low optimal temperature contrasted the optimal value (about 20 degrees C) for the steppe, and was likely due to the acclimation of most alpine plants to the long-term low temperature on the Tibet Plateau. We inferred that water stress was the primary factor causing depression of the FNEE in the semi-arid steppe ecosystem, while relative high temperature under strong solar radiation was the main reason for the decrease of FNEE in the alpine shrub. This study implies that different grassland ecosystems may respond differently to climate change in the future. (c) 2006 Elsevier B.V All rights reserved.

Floral closure in response to temperature and pollination in Gentiana straminea Maxim. (Gentianaceae), an alpine perennial in the Qinghai-Tibetan Plateau

Floral closure may be induced by pollination and various other factors, but is rarely studied comprehensively. Different kinds of floral closure should have various effects on reproductive fitness of plants. Two contrasting types of floral closure were observed in the flowers of Gentiana straminea Maxim. in the eastern Qinghai-Tibetan Plateau. The first type occurred prior to pollination during both gender phases, in response mainly to decreasing air temperatures. Flowers closed when decreasing temperatures approached 20 degrees C and subsequently began to reopen the following day during mid-morning when air temperatures warmed to approximately 13-15 degrees C. This kind of floral closure can protect pollen grains on either stamens or stigmas, increasing fitness of both male and female. Following pollination, permanent floral closure occurred, although there was a delay between the dates of pollination and permanent closure, during which flowers continued to show temporary closure in response to low temperature episodes. The time required for permanent, pollination-induced closure varied according to the age of the gender phase, including a prolonged time before closure if pollination occurred early in the female phase. The retaining of permanent closed flowers increased both approaching (to inflorescences) and visiting (to unpollinated flowers) frequencies of individual plants when with fewer open flowers and the persisting corolla is further beneficial for seed sets of these pollinated flowers. Thus, two separate types of floral closure, one in response to environmental cues and the other in response to the age of each gender stage, appeared to have a strong influence on reproductive fitness in this species. These results revealed a different adaptive strategy of alpine plants in the sexual reproduction assurance in addition to the well-known elevated floral longevity, dominant role of more effective pollinators and increased reproduction allocation in the arid habitats.

Digestibility, nutrient balance and urinary purine derivative excretion in dry yak cows fed oat hay at different levels of intake

A feeding trial A as conducted at the farm of Qinghai Academy of Animal and Veterinary Science, Xining, China during 1996 - 1997 with three dry yak cows (initial body weight 163 - 197 kg, age 5 - 6 years) by using 3 x 3 Latin Square Design to determine the effect of levels of feed intake on digestion, nitrogen balance and purine derivative excretion in urine of yak cows. The animals were fed oat hay (nitrogen 13.5 g/kg dry matter (DM), metabolisable energy 8.3 MJ/kg DM), i.e., 0.3, 0.6 and 0.9 of voluntary intake (VI). Each intake treatment lasted for 17 days and the samples (feeds, faeces and urine) were collected during last 7 days of each period. The results indicate that digestibility of dietary DM, OM, NDF and ash declined when intake levels increased from 0.3 to 0.9 VI [DM, from 66.1% to 59.1% (P < 0.05); OM, from 68.1% to 59.9% (P < 0.05); NDF, from 62.1% to 54.3% (P < 0.05); and ash, from 33.9% to 11.8% (P < 0.05)]. Around 0.10 g N/kg W-0.75 was deficient daily in yak cows at 0.3 VI, and positive N balances were observed at 0.6 and 0.9 VI. Intake levels significantly (P < 0.05) affected total PD excretion in yak urine. The proportion of allantoin increased (P < 0.05) and uric acid decreased (P < 0.05) as intake level of feed increased. (C) 2004 Elsevier B.V. All rights reserved.

预应力结构抗滑桩设计计算方法及其在滑坡治理中的应用研究

Landslide is a kind of serious geological hazards and its damage is very great. In recent years, landslides become more and more frequent along with increase of scale of engineering constructions and cause greater loss. Consequently, how to protect landslides has become important research subject in the engineering field. This paper improves the method how to compute landslide thrust and solves the irrational problem in the design of piles because of the irrational landslide thrust according to the theory and technology of existed anti-slide piles and pre-stressed cable anti-slide piles. Modern pre-stressing technology has been introduced and load balancing method has been used to improve the stressing behavior of anti-slide piles. Anchor cables, anti-slide piles and modern pre-stressing technology have been used to prevention complicated landslide. It is an important base to select values for the landslide thrust. An improved method to calculate design thrust of anti-slide piles has been presented in this paper on the base of residual thrust method by comparing existing methods to select values of landslide thrust in the design of anti-slide piles. In the method, residual landslide thrust behind the anti-slide piles and residual skid resistance before the piles has been analyzed, equitable distribution of residual landslide thrust behind the piles has been realized, and the method to select value of design thrust becomes more reasonable. The pre-stressed cable anti-slide piles are developed from the common anti-slide piles and are common method to prevent landslide. Their principle is that internal force of anti-slide piles is adjusted and size of section is diminished by changing constraint conditions of anti-slide piles. For landslides with deep slip surface and large scale of slopes, limitation of the method appears. Such landslides are in need of long piles and anchor cables which are not only non-economic but also can generate larger deformation and leave potential danger after prevention. For solving the problem, a new kind of anti-slide piles, inner pre-stressing force anti-slide piles, is presented in this paper, and its principle is that an additional force, which is generated in the inner anti-slide piles by arranging pre-stressed reinforcement or tight wire in a certain form in interior of anti-slide piles and stretching the steel reinforcement or tight wire, may balance out the internal force induced by landslide thrust whole or partly (load balancing method). The method will change bending moment which anti-slide piles are not good at bearing into compressive stress which piles are good at bearing, improve stressing performance of anti-slide piles greatly, diminish size of section, and make anti-slide piles not fissured in the natural service or postpone appearance of the fissures, and improve viability of anti-slide piles. Pre-stressed cable anti-slide piles and inner pre-stressing force anti-slide piles go by the general name of pre-stressed structure anti-slide piles in the paper, and their design and calculation method is also analyzed. A new calculation method is provided in the paper for design of anti-slide piles. For pre-stressed structure anti-slide piles, a new computation mode is firstly presented in the paper on the foundation of cantilever piles. In the mode, constraint form of load-bearing section of the anti-slide piles should be confirmed according to reservoir conditions in order to figure out amount of pre-stress of the anchor cables, and internal force should be analyzed for the load-bearing section of pre-stressed structure anti-slide piles so as to confirm anchorage section of anti-slide piles. Pre-stressed cables of the pre-stressed cable anti-slide piles can be arranged as required. This paper analyzes the load-bearing section of single-row and double-row pre-stressed cable anti-slide piles and provides a calculation method for design of the pre-stressed cable anti-slide piles. Inner pre-stressing force anti-slide piles are a new kind of structural style. Their load-bearing section is divided into four computation modes according to whether pre-stressed cables are applied for exterior of the anti-slide piles, and whether single-row or double-row exterior pre-stressed cables are applied. The load balancing method is used to analyze the computation modes for providing a method to design the inner pre-stressing force anti-slide piles rationally. Pre-stressed cable anti-slide piles and inner pre-stressing force anti-slide piles are applied to research on Mahe landfall in Yalong Lenggu hydropower station by the improved method to select value of design thrust of anti-slide piles. A good effect is obtained in the analysis.