重点学校与非重点学校的校长领导行为比较

我国重点学校制度的一个重要假设是重点学校可以把自身的高质量办学行为作为给其他普通学校的示范,但重点学校在办学上是否真的优于普通学校,学界和公众一直存在争论,并且已有争论大多没有证据支持。本研究运用全国5个城市60所学校校长问卷所获得的数据,对重点学校和非重点学校的校长领导行为进行分析。本研究获得的一个主要发现就是尽管重点学校和非重点学校在所有的背景变量上都存在显著差异,但它们的校长领导行为并不存在着明显的差异,重点学校有更好的办学质量这一假设并没有得到验证。本研究结果也提示,需要进一步关注为什么背景迥异的重点学校和非重点学校在校长领导行为上出现"同态化"趋势。

Diversity of Sucking Lice on Small Mammals in the Surrounding Areas of Erhai Lake in Yunnan,China

An investigation of sucking lice on the body surface of small mammals was carried out in the surrounding areas of Erhai Lake in Dali, Yunnan from 2003 to 2004. From investigation sites, 3 303 small mammal hosts were captured and identified into 7 families, 15 genera and 21 species in 4 orders （Rodentia, Insectivora, Scandentia and Carnivora）, while t4 635 individuals of sucking lice collected from the body surface of the small mammal hosts are identified into 5 families, 6 genera and 21 species in the Order Anoplura, The sites stand alongside three cordilleras surrounding the Erhai Lake, namely Eastern Wuliang Mountain, Southern Ailao Mountain and Western Cangshan Mountain. The three confined oriented areas are different landscapes within the same zone where the longitude, latitude, altitude and fauna are homologous but isolated by Erhai Lake as inartificial barrier. The aim of this study was to recognize features of the species diversity, abundance, community structure, similarity and distribution of sucking lice in different landscapes within the same zone. The results showed the species diversity of sucking lice was very low with a very simple community structure. The distribution of sucking lice and their corresponding hosts are quite uneven among different oriented areas and this may imply that ecological environment influences the species composition and distribution of sucking lice and their corresponding hosts. A certain species of hosts usually have their fixed louse species. The similarity of sucking louse communities is highly consistent with the affinity of small mammal hosts in taxonomy. Species of sucking lice on the same small mammal host in different oriented areas of Erhai Lake are homologous. The results strongly suggest a close relationship of co-evolution between sucking lice and their hosts.

Effect of electrochemical state on corrosion-wear behaviors of TC4 alloy in artificial seawater

The electrochemical and corrosion?wear behaviors of TC4 alloy in artificial seawater were studied. And the influences of electrochemical state on passive behavior, failure mechanism of passive film and corrosion?wear synergy were emphatically analyzed. The corrosion?wear analysis of the alloy was fulfilled by methods of mass loss, electrochemical testing and scanning electron microscope (SEM). It can be observed that the cathodic shift of open circuit potential and three order of magnitude increase of current density can be obtained during corrosion?wear process. Total corrosion?wear loss increases with increasing applied potential, confirming the synergy between wear and corrosion. High polarisation potential results in low coefficient of friction and high corrosion rate. The relative contribution of pure mechanical wear to total material loss deceases obviously with the increase of potential from open circuit potential to 0.9 V during corrosion?wear. Contributions of wear-induced-corrosion and corrosion-induced-wear are significant especially at higher potentials.

Static and dynamic collaborative optimization of ship hull structure

The goal of this effort was to provide a static and dynamic collaborative optimization （CO） model for the design of ship hull structure. The CO model integrated with static, mode and dynamic analyses. In the system-level optimization model, a new objective function was advised, integrating all the subsystem-levels＇ objective functions, so as to eliminate the effects of dimensions and magnitude order. The proposed CO architecture enabled multi-objectives of the system and subsystem-level to be considered at both levels during optimization. A bi-level optimization strategy was advised, using the multi-island genetic algorithm. The proposed model was demonstrated with a deck optimization problem of container ship stern. The analysis progress and results of example show that the CO strategy is not only feasible and reliable, but also well suited for use in actual optimization problems of ship design.

Anti-control and Generalized Synchronization of Chaos for a Kind of n-Dimensional Linear Differential System

This paper introduces the finding of some chaotic attractors in a kind of n-dimensional autonomous hybrid system, which is realized via applying some discontinuous state feedback to a kind of n linear differential system. And a constructive theorem is proposed for generalized synchronization related to the above chaotic hybrid systems. Examples are presented for illustrating the methods.

Simultaneous measurement of phase retardation and optic axis of wave plates

A simple method used for simultaneous measurement of phase retardation and optic axis of wave plate by employing 1/4 wave plate is demonstrated. The theoretical analysis of the measuring principle is presented in detail. In the measurement, after adjusting a standard 1/4 wave plate and the fast (slow) axis of the plate to be measured parallel to the pass axis of the polarizer, the plate to be measured is rotated by 450 counterclockwisly. A stepping motor is used to rotate the analyzer. The experimental data are collected by a photodetector and then sent to a computer. According to the output data curve, the phase retardation and optic axis of the plate to be measured can be obtained simultaneously. To test the feasibility of the method, a λ /2 and a λ /8 wave plates are used as examples to demonstrate the measurement procedures. The phase retardation measurement accuracy is better than 0.5×10-2. This method can be used to measure the arbitrary phase retardation conveniently.

A New Problem with Cross-Species Amplification of Microsatellites: Generation of Non-Homologous Products

Microsatellites have been widely used in studies on population genetics, ecology and evolutionary biology. However, microsatellites are not always available for the species to be studied and their isolation could be time-consuming. In order to save time and effort researchers often rely on cross-species amplification. We revealed a new problem of microsatellite cross-species amplification in addition to size homoplasy by analyzing the sequences of electromorphs from seven catfish species belonging to three different families （Clariidae, Heteropneustidae and Pimelodidae）. A total of 50 different electromorphs were amplified from the seven catfish species by using primers for 4 microsatellite loci isolated from the species Clarias batrachus. Two hundred and forty PCR-products representing all 50 electromorphs were sequenced and analyzed. Primers for two loci amplified specific products from orthologous loci in all species tested, whereas primers for the other two loci produced specific and polymorphic bands from some non-orthologous loci, even in closely related non-source species. Size homoplasy within the source species was not obvious, whereas extensive size homoplasy across species were detected at three loci, but not at the fourth one. These data suggest that amplification of products from non-orthologous loci and appearance of size homoplasy by cross-amplification are locus dependent, and do not reflect phylogenetic relationship. Amplification of non-orthologous loci and appearance of size homoplasy will lead to obvious complications in phylogenetie interference, population genetic and evolutionary studies. Therefore, we propose that sequence analysis of cross-amplification products should be conducted prior to application of cross-species amplification of microsatellites.

Singlet oxygen synergistic surface-adsorbed hydroxyl radicals for phenol degradation in CoP catalytic photo-Fenton

In recent years,there have been numerous studies on Fenton or Fenton-like reactions mediated by nonfree radicals such as singlet oxygen(1O_(2));however,there are few studies on the synergistic effect of 1O_(2) and free radicals on the degradation of organic molecules,such as phenol in Fenton reaction.In this study,a cocatalyst,CoP,commonly used in photocatalysis was synthesized using a simple two-step method,and a CoP/Fe^(2+)/AM1.5 system was constructed by introducing Fe^(2+)and simulated sunlight(AM1.5)irradiation.The newly constructed CoP/Fe^(2+)/AM1.5 system could effectively degrade various organic pollutants,including dyes,phenols,and antibiotics.Radical quenching experiments and electron paramagnetic resonance detection confirmed that there were three reactive oxygen species(ROS)in the CoP/Fe^(2+)/AM1.5 system,including·OH_(ads),·O_(2)^(-),and 1O_(2).Further,combined with the liquid chromatogram of phenol,its intermediate products,and the fluorescence diagram of o-hydroxybenzoic acid,it can be concluded that a synergistic effect exists between 1O_(2) and the surface-adsorbed·OH_(ads) in the CoP/Fe^(2+)/AM1.5 system.The controllable formation of surface 1O_(2) and·OH_(ads) was achieved through the oxidation(Co^(3+))and reduction(Pδ−)centers exposed on the CoP surface,and the synergistic effect between them results in phenol’s hydroxylation,ring-opening,and degradation.The study of this new mechanism provides a new perspective for revealing the surface interface reaction between ROS and organic pollutants.

Adjoint Assimilation in Marine Ecosystem Models and an Example of Application

This paper aims at a review of the work carried out to date on the adjoint assimilation of data in marine ecosys-tem models since 1995. The structure and feature of the adjoint assimilation in marine ecosystem models are also introduced. To illustrate the application of the adjoint technique and its merits, a 4-variable ecosystem model coupled with a 3-D physical model is established for the Bohai Sea and the Yellow Sea. The chlorophyll concentration data derived from the SeaWiFS o-cean colour data are assimilated in the model with the technique. Some results are briefly presented.

Solution of Chemical Dynamic Optimization Using the Simultaneous Strategies

An approach of simultaneous strategies with two novel techniques is proposed to improve the solution accuracy of chemical dynamic optimization problems. The first technique is to handle constraints on control vari- ables based on the finite-element collocation so as to control the approximation error for discrete optimal problems, where a set of control constraints at dement knots are integrated with the procedure for optimization leading to a significant gain in the accuracy of the simultaneous strategies. The second technique is to make the mesh refine- ment more feasible and reliable by introducing length constraints and guideline in designing appropriate element length boundaries, so that the proposed approach becomes more efficient in adjusting dements to track optimal control profile breakpoints and ensure accurate state and centrol profiles. Four classic benchmarks of dynamic op- timization problems are used as illustrations, and the proposed approach is compared with literature reports. The research results reveal that the proposed approach is preferz,ble in improving the solution accuracy of chemical dy- namic optimization problem.

Different Attitudes in Different Regions Aimed at Military Personnel in Turkey

Historically Turks had always relied on military power. The culture is rich with martial values to this day. Even each civilian is somewhat soldierly in a sense, in general. Nevertheless, in a more detailed analysis, in some territories of the country, the prestige enjoyed by the military is more intensive than the average, while in some other territories, respect for military people is much below the average tendency. One might infer that in the former category, it is a question of the regions where the inhabitants are mild, soft-spoken, and compatible. They accordingly admire discipline and display obedient attitudes vis-a-vis governmental authority ever since the Ottoman times, merely as a cultural and traditional trait. Those regions are certainly places where military people today are held in high esteem. In such locations, even the ideal profession for a little boy is indoctrinated as a military career, by the whole family or the surrounding social environment. It should be mentioned that in certain cities and towns, a substantial percentage of the population are represented by immigrants, who got re-patriated along the course of the near history, as the former Ottoman Empire began shrinking in territory due to loss of land, during successive wars. The crushing majority of the Muslim Ottoman subjects in those lost territories preferred leaving their property and escaping into the Anatolian mainland, rather than renouncing their belief and assimilating to the new political regime. Having suffered at the hands of foreign powers, those people have also been especially appreciative of the value of their own soldiers. As for the latter category, dislike of discipline and authority can be mainly attributed to the special social structure and historical circumstances.

Collaboration strategy for software dynamic evolution of multi-agent system

As the ability of a single agent is limited while information and resources in multi-agent systems are distributed, cooperation is necessary for agents to accomplish a complex task. In the open and changeable environment on the Internet, it is of great significance to research a system flexible and capable in dynamic evolution that can find a collaboration method for agents which can be used in dynamic evolution process. With such a method, agents accomplish tasks for an overall target and at the same time, the collaborative relationship of agents can be adjusted with the change of environment. A method of task decomposition and collaboration of agents by improved contract net protocol is introduced. Finally, analysis on the result of the experiments is performed to verify the improved contract net protocol can greatly increase the efficiency of communication and collaboration in multi-agent system.

Intra-clutch variation in egg appearance assessed by human vision does not relate to rejection of parasite eggs in Iberian Azure-winged Magpies

e coevolutionary arms race between cuckoos and their hosts predicts that low variation in egg features within a host clutch would facilitate discrimination of mimetic parasite eggs.Here,we experimentally examine this prediction by using arti cial and natural parasite eggs showing contrasting level of matching with host eggs.We quanti ed,based on human assessment,intra-clutch variation in egg appearance and egg discrimination in the Iberian Azure-winged Magpie(Cyanopica cyanus),a presumed former host of the Great Spotted Cuckoo(Clamator glandarius).Azure-winged Magpies rejected parasitic eggs in relation to their degree of dissimilarity with own eggs:Great Spotted Cuckoo model eggs were relatively more o en rejected(73.7%) than real Great Spotted Cuckoo eggs(44.4%) and the less contrasting conspeci c eggs(35.5%).Contrary to our predictions,we found that,irrespective of mimicry level of parasitic eggs,intra-clutch variation in host egg appearance did not di er signi cantly between rejecters and acceptors.We found,however,that individuals with higher variation in egg-size were almost signi cantly more prone to be rejecters than individuals showing lower variation in egg size.Our results do not support the hypothesis that the extent of intraclutch variation in egg discrimination varied with parasite egg mimicry in this particular system,and add to previous ndings suggesting that perhaps an increase in intra-clutch variation in egg appearance,rather than a decrease,might be advantageous when discriminating against non-mimetic Great Spotted Cuckoo eggs.

Microaerobic iron oxidation and carbon assimilation and associated microbial community in paddy soil

Iron oxidation is a prevalent and important biogeochemical process in paddy soil,but little is known about whether and how microbially mediated iron oxidation is coupled with carbon assimilation,particularly under microaerobic conditions.Here,we investigated kinetics of CO_2 assimilation and Fe(Ⅱ)oxidation in an incubation experiment with paddy soil under suboxic conditions,and profiled the associated microbial community using DNA-stable isotope probing and 16S r RNA gene-based sequencing.The results showed that CO_2 assimilation and Fe(II)oxidation in the gradient tubes were predominantly mediated by the microbes enriched in the paddy soil,primarily Azospirillum and Magnetospirillum,as their relative abundances were higher in the^( 13)C heavy fractions compared to^( 12)C heavy fractions.This study provided direct evidence of chemoautotrophic microaerophiles linking iron oxidation and carbon assimilation at the oxic–anoxic interface in the paddy soil ecosystem.

Actinide-uranium single-atom catalysis for electrochemical nitrogen fixation

Actinide-based catalysts have been regarded as promising candidates for N_(2) fixation owing to their unique 5f orbital with flexible oxidation states.Herein,we report for the first time the dispersion of uranium(U)single atoms on TiO_(2) nanosheets via oxygen vacancy confinement for N_(2) electroreduction.The single-atom U catalyst exhibited a high NH_(3) yield of 40.57μg h^(-1) mg^(-1),with a reasonably high Faraday efficiency of 25.77%,ranking first among the reported nitrogen-free catalysts.Isotope-labeling operando synchrotron infrared spectroscopy verifies that the key*N_(2)H_(y) intermediate species was derived from the N_(2) gas of the feed.By using operando X-ray absorption spectroscopy,we found enhanced metal-support interaction between U single atoms and TiO_(2) lattice with more U-O_(latt) coordination under working conditions.Theoretical simulations suggest that the evolved 1O_(ads)-U-4O_(latt) moieties act as a critical electronfeedback center,lowering the thermodynamic energy barrier for the N_(2) dissociation and the first hydrogenation step.This work provides the possibility of tailoring the interaction between metal active sites and supports for designing high-performance actinide-based single-atom catalysts.

Simultaneous estimation of soil moisture and hydraulic parameters using residual resampling particle filter

Land data assimilation(DA) has gradually developed into an important earth science research method because of its ability to combine model simulations and observations.Integrating new observations into a land surface model by the DA method can correct the predicted trajectory of the model and thus,improve the accuracy of state variables.It can also reduce uncertainties in the model by estimating some model parameters simultaneously.Among the various DA methods,the particle filter is free from the constraints of linear models and Gaussian error distributions,and can be applicable to any nonlinear and non-Gaussian state-space model;therefore,its importance in land data assimilation research has increased.In this study,a DA scheme was developed based on the residual resampling particle filter.Microwave brightness temperatures were assimilated into the macro-scale semi-distributed variance infiltration capacity model to estimate the surface soil moisture and three hydraulic parameters simultaneously.Finally,to verify the scheme,a series of comparative experiments was performed with experimental data obtained during the Soil Moisture Experiment of 2004 in Arizona.The results show that the scheme can improve the accuracy of soil moisture estimations significantly.In addition,the three hydraulic parameters were also well estimated,demonstrating the effectiveness of the DA scheme.

Homogenization of climate series:The basis for assessing climate changes

Long-term meteorological observation series are fundamental for reflecting climate changes.However,almost all meteorological stations inevitably undergo relocation or changes in observation instruments,rules,and methods,which can result in systematic biases in the observation series for corresponding periods.Homogenization is a technique for adjusting these biases in order to assess the true trends in the time series.In recent years,homogenization has shifted its focus from the adjustments to climate mean status to the adjustments to information about climate extremes or extreme weather.Using case analyses of ideal and actual climate series,here we demonstrate the basic idea of homogenization,introduce new understanding obtained from recent studies of homogenization of climate series in China,and raise issues for further studies in this field,especially with regards to climate extremes,uncertainty of the statistical adjustments,and biased physical relationships among different climate variables due to adjustments in single variable series.

Convergent evolution of brain morphology and communication modalities in lizards

Animals communicate information within their environments via visual, chemical, auditory, and/or tactile modalities. The use of each modalityis generally linked to particular brain regions, but it is not yet known whether the cellular morphology of neurons in these regions has evolved in association with the relative use of a modality.We investigated relationships between the behavioral use of communication modalities and neural morphologies in six lizard species. Two of these species （Anolis carol# nensis and Leiocephalus carinatus） primarily use visual signals to communicate with conspecifics and detect potential prey, and two （Aspidoscelis gularis and Scincella lateralis） communicate and forage primarily using chemical signals. Two other species （Hemidactylus turcicus and Sceloporus olivaceus） use both visual and chemical signals. For each species, we performed beha- vioral observations and quantified rates of visual and chemical behaviors. We then cryosectioned brain tissues from 9-10 males of each species and measured the soma size and density of neurons in two brain regions associated with visual behaviors （the lat- eral geniculate nucleus and the nucleus rotundus） and one region associated with chemical behaviors （the nucleus sphericus）. With analyses conducted in a phylogenetic context, we found that species that performed higher rates of visual displays had a denser lateral geniculate nucleus, and species that used a higher proportion of chemical displays had larger somas in the nucleus sphericus. These relationships suggest that neural morphologies in the brain have evolved convergently in species with similar communication behaviors .

Nest-site Choice and Breeding Success among Four Sympatric Species of Passerine Birds in a Reedbed-dominated Wetland

The efficacy of nest-site choice ultimately determines the breeding success of birds. Comparisons of the reproductive strategies of various bird species which inhabit the same habitat may provide insights on the evolution of the diverse life-history strategies in birds. In this study, nest-site choice and breeding success of four species of passerine birds that rely on reeds for reproduction were investigated in a wetland in Hebei, China. The four species were the Oriental reed warbler(Acrocephalus orientalis)(ORW), the blunt-winged warbler(Acrocephalus concinens)(BW), the reed parrotbill(Paradoxornis heudei)(RP), and the vinous-throated parrotbill(Sinosuthora webbiana)(VP). Our results showed that breeding nests of the four species were distributed in a mosaic pattern within the same habitat, with similar nest shapes/structures and nest-sites in the reeds. The only characteristics which differed significantly among the species were nest height above the water surface, height of reeds where nests were placed, and density of reeds around the nest site. In addition, the starting time of reproduction clearly differed for the four species. The breeding success rates of the four species were 34.5%(86/249) for ORW, 35.3%(6/17) for BW, 38.5%(15/39) for RP, and 40.9%(9/22) for VP in the two study years. The main factors affecting the breeding success were nest predation and poor weather conditions, like heavy rainstorms and wind, while nest parasitism by the common cuckoo(Cuculus canorus) represented an important factor for breeding failure only in the Oriental reed warbler. Our study demonstrated that these four sympatric species of passerine birds inhabiting the same wetland exhibit differences in terms of nest-site choice and breeding phenology.

Nitrate assimilation by marine heterotrophic bacteria

Nitrate assimilation is a process where bacteria utilize nitrate as a nitrogen source and synthesize it into organic nitrogen. We found that nitrate-assimilating bacteria(NAB) are widely distributed in various marine environments, from surface to the deep ocean and sediment, which indicates that NAB are significant to the oceanic nitrogen cycle. Comparative genomic analysis revealed nitrate-assimilating genes(nas A) in these marine heterotrophic NAB showed different gene arrangements and diverse regulation systems. Summary on recent findings will contribute to understanding the process of nitrate assimilation in NAB and their ecological significance in the nitrogen cycle. A systematic analysis of a number of studies on bacterial nitrate assimilation in marine ecological systems was conducted to clarify directions for future research.