Oracle8i行链接和行迁移探析

探讨了行迁移和行链接产生的原因,分析了行迁移和行链接对Oracle数据库性能造成的影响,以及如何识别行迁移和行链接,并提供了一种检测和消除行迁移和行链接的有效方法。

结合全国公民身份信息系统浅谈行链接/行迁移的清除

在海量数据库应用系统的运行过程中,我们经常会发现系统性能随着时间的推移逐渐下降,虽然采用了很多方法优化,但是都无法达到令人满意的效果,这时我们可以检查数据库有没有发生行迁移和行链接。消除行迁移和行链接可以提高系统的性能。

消除行迁移与Oracle数据库性能调优

本文介绍了在Oracle数据中行迁移(RM)的概念,RM的形成,其对数据库性能的影响,如何消除RM,以及对其在UT mSwitch系统中的实际应用的理论参考。

Extractability and Mobility of Copper and Zinc Accumulated in Sandy Soils

Extractability and mobility of Cu and Zn and their relationships with 1) accumulation of Cu and Zn and 2) soil pH were studied in three sandy soils (Wabasso, Ankona, and Winder) from commercial citrus groves in Florida, USA. The soils, with a broad range of Cu and Zn concentrations, were fractionated by a modified procedure of Amacher, while Cu and Zn mobility were evaluated using column leaching. The extractability of Cu and Zn increased with decreasing soil pH. Also with increasing total soil Cu and Zn for extractable Cu in the Wabasso sand a threshold level, where the metal extraction rate increased, was noted at 100 mg kg-1, whereas for extractable Zn in the Wabasso sand the threshold level was found at 60 mg kg-1 and in the Ankona sand at 120 mg kg-1. These results suggested that the release potential of Cu and Zn was greater in the Wabasso sand than in the Ankona sand. The column leaching experiment showed that at total soil Cu or Zn concentrations < 100 mg kg-1 all leachates had low Cu and Zn concentrations. However at total concentrations > 200 mg kg-1 for Cu and > 150 mg kg-1 for Zn with decreasing soil pH, the concentrations of both Cu and Zn in the leachates increased exponentially. Also in these sandy soils soluble Cu and Zn mainly originated from the exchangeable fractions, and pH was a key factor controlling Cu and Zn extractability and mobility.

Effect of Nitrogen Fertilizers on Movement and Transformation of Phosphorus in an Acid Soil

The effects of two different nitrogen fertilizers （urea and NH4C1） with monocalcium phosphate （MCP） on the movement and transformation of fertilizer P in soil microsites along with soil pH changes at different distances from the fertilizer application site were studied in an incubation experiment. A highly acidic red soil （Ultisol, pH 4.57） from south China with MCP fertilizer alone or in combination with NH4C1 or urea was added to the surface of soil cylinders and packed in wax blocks. After 7 and 28 days, the extraction and analysis of each 2 mm layer from the interface of the soil and fertilizer showed that added NH4C1 or urea did not change the movement distance of fertilizer P. However, P transformation was significantly affected （P 〈 0.05）. After 7 days, at 0-8 mm distance from the fertilizer site the addition of urea significantly decreased the water-extractable P concentration; however, after 28 days the effect of N addition had disappeared. Also,at limited distances close to the fertilizer site NH4Cl application with MCP significantly increased acid-extractable P and available P, while with the addition of urea they significantly decreased. Compared with application of MCP alone,addition of urea significantly increased soil pH in fertilizer microsites, whereas the addition of NH4Cl significantly decreased soil pH.

Behaviours of Main Elements in Soil-Forming Processesof Fildes Peninsula, the Maritime Antarctic

Nine horizon samples of three soil profiles representative of Dystri-gelic Cambisol, Fibri-gelic Histosoland Relic Ornithosol were taken from Fildes Peninsula of King George Island, Antarctica, to quantitativelydemonstrate the enrichment, migration and loss of the elements (Si, Al, Fe, Ca, Mg, Mn, K, Na and P) insoil horizons and their behaviours within profiles by application of the concept of the enrichment coefficientcalculated in terms of the abundance of Ti. Besides, six horizon samples of 4 other profiles randomly takenfrom the studied area were examined for calculation of the redistributing enrichment coefficient, which wasapplied for a better understanding of the element redistribution between soil and clay fraction along with soildevelopment. The results showed that the enrichment, migration and redistribution of the elements variedstrongly among the investigated soils and horizons, due to the differences of weathering degrees and moisturestatus, influences of sea bird activities, etc.

REALIZATION OF QUICK-LOOK IMAGING FOR SPACEBORNE SAR BASED ON PARALLEL PROCESSING

Large range cell migration is a severe challenge to imaging algorithm for spaceborne SAR. Based on design of Finite Impulse Response (FIR) filter and Range Doppler (RD) algorithm, a realization of quick-look imaging for large range cell migration is proposed. It realized quick-look imaging of 8 times reduced resolution with parallel processing on memory shared 8 CPU SGI server. According to simulation experiment, this quick-look imaging algorithm with parallel processing can image 16384x16384 SAR raw data within 6 seconds. It reaches the requirement of real-time imaging.

Fuel load and flight ranges of blackcaps Sylvia atricapilla in northern Iberia during autumn and spring migrations

Fuel accumulation, mainly as fatty acids, is one of the main characteristics of migratory, birds. Studying to what extent each population or species manages fuel load and how it varies along routes of migration or between seasons （autumn and spring migrations） is crucial to our understanding of bird migration strategies. Our aim here was to analyse whether migratory blackcaps Sylvia atrieapilla passing through northern Iberia differ in their mean fuel loads, rate of fuel accumulation and ＇ potential＇ flight ranges between migration seasons. Blackcaps were mist netted for 4 h-periods beginning at dawn from 16 September to 15 November 2003 - 2005, and from 1 March to 30 April 2004 - 2006 in a European Atlantic hedgerow at Loza, northern Iberia. Both fuel load and fuel deposition rate （this latter assessed with difference in body mass of within-season recaptured individuals） were higher in autumn than in spring. Possible hypotheses explaining these results could be seasonal-associated variations in food availability （likely lower during spring than during autumn）, the fact that a fraction of the migrants captured in spring could breed close to the study area and different selective pressures for breeding and wintering

Study on a Novel Disphase Supplying Supported Liquid Membrane for Transport Behavior of Divalent Nickel Ions

A novel d!sphase supplying supported liquid membrane （DSSLM）, containing supplying feed phase andsupplying stripping phase tor transport behavior ot NI（Ⅱ）, have been studied. The supplying supported feed phase included feed solution and di（2-ethyhexyl） phosphoric acid （HDEHP） as the carrier in kerosene, and supplying stripping phase included HDEHP as the cartier in kerosene and HC1 as the stripping agent. The effects of volume ratio of membrane solution to feed solution （O/F）, pH, initial concentration of Ni（Ⅱ） and ionic strength in the feedsolution, volume ratio of membrane solution to stripping solution （O/S）, concentration of H2SO4 solution, HDEHP concentration in the supplying stripping phase on transport of Ni（/I）, the advantages of DSSLM compared to the traditional supported liquid membrane （SLM）, the system stability, the reuse of membrane solution and the reten- tion of membrane phase were studied. Experimental results indicated that the optimum transpgrt of Ni（Ⅱ） was oh-tained when H2SO4 concentration was 2.00 mol＇L-＇, HDEHP concentration was 0.120 mol·L-1, and O/S was 4· 1 in the supplying stripping phase, O/F was 1 ： 10 and pH was 5.20 in the supplying feed phase. The ionic strength in supplying feed phase had no obvious effect on transport of Ni（Ⅱ）. When initial Ni（Ⅱ） concentration was 2.00x 10-4 mol/L, the transport percentage of Ni（Ⅱ） was up to 93.1% in 250 min. The kinetic equation was deduced in terms of the law of mass diffusion and the interface chemistry.

THE MIGRATION SCHEME BASED ON SCHEMA THEOREM OF PGAs

Genetic Algorithms (GAs) are efficient non-gradient stochastic search methods and Parallel GAs (PGAs) are proposed to overcome the deficiencies of the sequential GAs, such as low speed, aptness to local convergence, etc. However, the tremendous increase in the communication costs accompanied with the parallelization stunts the further improvements of PGAs. This letter takes the decrease of the communication costs as the key to this problem and advances a new Migration Scheme based on Schema Theorem (MSST). MSST distills schemata from the populations and then proportionately disseminates them to other populations, which decreases the total communication cost among the populations and arms the multiple-population model with higher speed and better scalability.

A Biologic Behavior Simulation: Living Migration Algorithm (LMA)

Biologic behaviors are the principal source for proposing new intelligent algorithms. Based on the mechanism of the bio-subsistence and the bio-migration, this paper proposes a novel algorithm—Living Migration Algorithm (LMA). The original contributions of LMA are three essential attributes of each individual: the minimal life-needs which are the necessaries for survival, the migrating which is a basal action for searching new living space, and the judging which is an important ability of deciding whether to migrate or not. When living space of all individuals can satisfy the minimal life-needs at some generation, they are considered as the optimal living places where objective functions will obtain the optima. LMA may be employed in large-scale computation and engineering field. The paper mostly operates LMA to deal with four non-linear and heterogeneous optimizations, and experiments prove LMA has better performances than Free Search algorithm.

Scaling Behavior of an Aggregation-Migration Model

We study the kinetic behavior of a two-species aggregation-migration model in which an irreversible aggregation occurs between any two clusters of the same species and a reversible migration occurs simultaneously between two different species. For a simple model with constant aggregation rates and with the migration rates and , we find that the evolution behavior of the system depends crucially on the values of the indexes υ1 and υ2. The aggregate size distribution of either species obeys a conventional scaling law for most cases. Moreover, we also generalize the two-species system to the multi-species case and analyze its kinetic behavior under the symmetrical conditions.

ON THE CLASSIFICATION OF SPEECH ACT REFUSALS IN CHINESE:EVIDENCE AND MOTIVATING FACTORS

This paper examines the phenomenon of sociocultural transfer and its motivating factors within the realization patterns of speech act refusal by Chinese EFL learners. EFL refusal data were collected using a written data collection test (DCT), which was designed and then followed by semi-structured interviews. Using semantic formulas as units of analysis, EFL refusal responses were compared with similar data elicited from native speakers of English. The results show two areas in which sociocultural transfer is existent in EFL learners' speech: options of selecting semantic formulas and content of semantic formulas. Each was found to reflect cultural values transferred from Chinese to English. Furthermore, based on the interview data, it was found that learners' social system and political factors, traditional socio-psychological ideology and economy possibly motivate sociocultural transfer.

文件制播环境下场序错乱的解决

最近几年，大家发现了电视图像的一类非常明显的缺陷。就是图像中物体或人的运动等画面出现类似抖动、闪烁、模糊、重影等现象。如果画面中还有游走或片尾上滚字幕，字符将会严重跳动、闪烁，非常刺眼：如果画面中有从左到右运动的汽车．在速度较低时，汽车的移动影像应该非常清晰，但实际上非常糊影，既似拖尾，又似重影，画面跳变，视觉效果难以忍受。

SPECIAL ISSUE： MIGRANT WORKESR IN THE COURSE OF URBANIZATION Factors influencing the migration intentions of rural workers in the Pearl River Delta

The focus of this article is this question： under China＇s present household registration system, what factors influence migrant workers＇ decisions to obtain urban household registration in order to stay permanently in the city？ Our research finds that if willingness to give up their land is used as the indicator for behavioral permanent migration, the main factors that influence migrant workers＇ intention to migrate will be their individual motives for migration, i.e. choices based on economic rationality. If wishing to transfer their household registration to the cities where they work is used as the indicator for institutional permanent migration, the main factors that influence their intentions will be regional conditions and the pressure of institutional legitimacy, and their choices will be socially rational in that they are seeking institutional protection to improve their life in the city. Groups with different aspirations vary in their individual motivations for migration and the degree to which they feel the pressure of institutional legitimacy.

Morphology, flight performance, and water crossing tendencies of Afro-Palearctic raptors during migration

Raptors primarily use soaring-gliding flight which exploits thermals and ridge lifts over land to reduce energetic costs However during migration, these birds often have to cross water surfaces where thermal currents are weak; during these times, birds mainly use flapping （powered） flight which increases energy consumption and mortality risk. As a result, some species have evolved strategies to reduce the amount of time spent over water by taking extensive detours over land. In this paper, we con- ducted a meta-analysis of water-crossing tendencies in Afro-Palearctic migrating raptors in relation to their morphology, their flight performance, and their phylogenetic relationships. In particular, we considered the aspect ratio （calculated as the wing span squared divided by wing area）, the energetic cost of powered flight, and the maximum water crossing length regularly performed by adult birds. Our results suggest that energy consumption during powered flight predominately affects the ability of raptors to fly over water surfaces

A meta-analysis of the effects of geolocator application on birds

An increasing trend in use of tracking devices such as geolocators is based on the assumption that the information gathered from such devices provides reliable information about the migratory behavior of free-living birds. This underlying as- sumption is rarely tested, as evidenced by the absence in many studies of controls, in particular treated controls, and so far never with a reasonable statistical power. Published studies have shown reduced survival prospects or delayed breeding in some species, suggesting that there may be reason to doubt that tracking devices provide unbiased information. Therefore, we conducted a meta-analysis of studies applying geolocators to wild birds to determine whether geolocators affected fitness components. Ge- olocators had an overall negative effect on fitness components, in particular survival, and ecological variables. Effect size was larger for aerial foragers than for other species. Moreover the leg band attachment method was more detrimental for birds than the leg-loop backpack harness. A meta-regression model of effect size showed independent negative effects of geolocators on ae- rial foragers, smaller species, species with smaller migration distances and in studies where geolocators were attached with a ring. These results suggest that geolocator studies should be interpreted with caution, but also raise questions whether it is ethically defensible to use geolocators on aerial foragers or small species without carrying out robust pilot studies.

Interspecific comparison of the flight performance between sparrowhawks and common buzzards migrating at the Falsterbo peninsula： A radar study

In order to compare the two species＇ flight performance over the exposed and windy Falsterbo Peninsula, where thermal conditions seldomly are very favorable, we used tracking radar to study flight parameters of sparrowhawks Accipiter ni- sus and common buzzards Buteo buteo during autumn migration. The results showed a clear difference between sparrowhawks and common buzzards in their flight altitudes and speeds, and in the wind conditions they encountered. Common buzzards had higher flight altitudes and were more selective of wind. Flight altitude was negatively related to the wind speed, which was most pronounced for common buzzards. Sparrowhawks had higher mean air- and cross-country speeds than common buzzards. Air- speed was negatively related, whereas ground and cross-country speeds were positively related to the tailwind component for both raptors. The differences between sparrowhawks and buzzards could to a large degree be explained by a larger dependence on thermal soaring among the common buzzards; a strategy associated with selectivity for favourable thermal and wind conditions during migratory flight. An additional important explanation for the interspecific differences was the habit of the sparrowhawks to combine migratory flight with hunting for prey, which makes it prone to fly at lower altitudes and use flapping flight to a much larger degree than common buzzards which do not forage during their migratory passage of the Falsterbo Peninsula [Current Zoo- logy 60（5）： 670-679, 2014].

ROLE OF DISEASE PROPAGATION IN MIGRATORY BIRD POPULATION

Chatterjee considered a predator prey model with avian migration in the migration prey population IS. Chatterjee, Alternative prey source coupled with prey recovery enhance stability between migratory prey and their predator in the presence of disease, Nonlinear Anal. Real World Appl. 11 （2010） 4415-4430]. In this paper, we modify and analyze the model by taking time dependent parameters and the general flmctional response into consideration. The conditions for the persistence of the system and the extinction of the disease are obtained. The global attractivity of the system is also studied. By numerical simulations, we find that the qualitative behavior of the system independent on the choice of the functional response. Moreover, it is observed that the infection rate, recruitment rate and the predation rate play a vital role in predicting the behavior of the dynamics.