美国统计学中的“指示数字”及其在经济中的应用

美国统计专家根据他们长期考察宏观经济的经验,提出了“指示数字”的统计指标及其编制方法和图示法。一、指示数字的分类美国专家设立的指示数字分成三组,现分述如下: 1.领先的指示数字由于经济发展对日常生活产生很大的影响。

附带瓦数指示的电灯泡测试器

如果只想知道电灯泡是否能用,灯泡测试器就不一定需要,只需将一只已知的好灯泡代换一试便知。但是,一个无需高压电源的测试器却更安全。还有另一种情况,如有一只坏灯泡需替换,而取出的一只备用灯泡的瓦数又不明确,那么像这样的测试仪就可派上用场。一个欧姆表就可判断出一个灯泡灯丝的好坏。

三苯基丙烯腈衍生物的构效关系研究

应用分子力学方法 MM+ 和半经验量子化学 AM1法得到了 2 2种三苯基丙烯腈衍生物的优势构象 ,利用量子化学算法和分子图形学技术获得电子结构参数和几何结构参数 ,采用多元线性回归分析和人工神经网络误差反传算法 ,将这些参数和三苯基丙烯腈衍生物在 0℃下与小牛子宫雌激素受体间的亲和力相关 .结果表明 ,三苯基丙烯腈衍生物在 0℃下与小牛子宫雌激素受体间亲和力大小与 X位羟基指示数、1号碳原子与 5号碳原子间键级、15号碳原子与 16号碳原子间键长和衍生物疏水性参数的相关性较好 ,建立了 2 2种三苯基丙烯腈衍生物的构效关系式 .

A non-parametric indicator Kriging method for generating coastal sediment type map

Coastal sediment type map has been widely used in marine economic and engineering activities, but the traditional mapping methods had some limitations due to their intrinsic assumption or subjectivity. In this paper, a non-parametric indicator Kriging method has been proposed for generating coastal sediment map. The method can effectively avoid mapping subjectivity, has no special requirements for the sample data to meet second-order stationary or normal distribution, and can also provide useful information on the quantitative evaluation of mapping uncertainty. The application of the method in the southern sea area of Lianyungang showed that much more convincing mapping results could be obtained compared with the traditional methods such as IDW, Kriging and Voronoi diagram under the same condition, so the proposed method was applicable with great utilization value.

《浮力实验》用弹簧秤比较好

一次去一所学校听课,发现一位教师在教小学自然第五册第十课的《浮力实验二》时,让学生观察系重物的橡皮筋长度(或用直尺量橡皮筋的长度),在空气中和水中的变化,间接探测物体在水中受到的浮力。由于做实验用的重物体积不大,在水中受到的浮力也不太大,使橡皮筋的伸缩变化不明显,所以很多学生很难得出正确结论。

商场怎样防内窃(三)

大多数送货过程发生的盗窃,在卡车上路之前就能够得到制止.防范措施如下:(1)将卡车和拖车的货箱门锁好并予加封.这些锁最好是与卡车连在一起的具高保险系数的挂锁,以防被不忠实的司机掉换.挂锁结构最好是带有字母密码的那种类型,或是一种配有可移动锁栓钥匙的类型,并且不允许司机接触车箱的挂锁密码或钥匙.送货前期重点在控制好送货卡车货箱的专用钥匙上.应由商场经理将专用钥匙及开锁密码装在信封里并密封好.待临送货前委托司机转交给收货部门主管.只要锁与钥匙的安全问题得到有效控制,那么发货前的防盗安全一般能够维持1～2个月.此后须再更换密码与钥匙,以将泄密的可能性减到最低程度.

调温电熨斗不调温的原因及修理

调温电熨斗不调温的原因及修理调温电熨斗的最大特点是能够根据所烫衣物质地的需要，任意调节温度。但是，有时会出现不调温的情况。当其通电后，一般达到了所需温度，指示灯就会熄灭；如果不能调温，即使温度超过了限值指示灯也不熄灭。调温电熨斗不调温，是由于控温器的...

Isothermal and nonisothermal crystallization kinetics of bio-sourced nylon 69

Bio-sourced nylon 69,one of promising engineering plastics,has a great potential in developing sustainable technology and various commercial applications.Isothermal and nonisothermal crystallization kinetics of nylon 69 is a base to optimize the process conditions and establish the structure–property correlations for nylon 69,and it is also highly bene ficial for successful applications of nylon products in industry.Isothermal and nonisothermal crystallization kinetics has been investigated by differential scanning calorimetry for nylon 69,bio-sourced even–odd nylon.The isothermal crystallization kinetics has been analyzed by the Avrami equation,the calculated Avrami exponent at various crystallization temperatures falls into the range of 2.28 and 2.86.In addition,the Avrami equation modi fied by Jeziorny and the equation suggested by Mo have been adopted to study the nonisothermal crystallization.The activation energies for isothermal and nonisothermal crystallization have also been determined.The study demonstrates that the crystallization model of nylon 69 might be a twodimensional(circular)growth at both isothermal and nonisothermal crystallization conditions.Furthermore,the value of the crystallization rate parameter(K)decreases signi ficantly but the crystallization half-time(t1/2)increases with the increase of the isothermal crystallization temperature.To nonisothermal crystallization,the crystallization rate increases as the cooling rate increases according to the analysis of Jeziorny's theory.The results of Mo's theory suggest that a faster cooling rate is required to reach a higher relative degree of crystallinity in a unit of time,and crystallization rate decreases when the relative degree of crystallinity increases at nonisothermal crystallization conditions.

Cultivation Influences on Soil Organic Carbon Associated with Texture in Seasonally Frozen Zones

[Objective] This study aimed to examine indicative roles of texture representing soil organic carbon presence and variability subsequent to cultivation under cold temperate climates with seasonal freeze-thaw events. [Method] Three chronosequences were selected for paired comparisons. Soil samples were collected at six depths with a 10 cm increment. Analysis of variance with general linear model and regression was performed for statistical analysis. [Result] In seasonally frozen soils where fragmentation of macroaggregates was stimulated, soil organic carbon level was positively associated with clay + silt proportion due to a wider textural range, better than sole clay content. Exponential function better fitted the experimental data to present progressively increased effectiveness of clay + silt content in maintaining carbon. Clay content explained 12%-41% and 14%-43% of variation via linear and exponential functions, respectively. Accordingly, clay + silt content explained 47%-65% and 46%-70%. [Conclusion] Texture reflected soil organic carbon occurrence as consequences of reclamation. For seasonally frozen soils with wider textural ranges, it is robust to adapt clay + silt content as dependent variable and exponential function. The generated algorithms provided an available pathway to estimate soil organic carbon losses following cultivation and to evaluate soil fertility.

Involvement of methylation-associated silencing of formin 2 in colorectal carcinogenesis

AIM To investigate whether promoter methylation is re-sponsible for the silencing of formin 2 （ FMN2） in colorectal cancer （CRC） and to analyze the association between FMN2 methylation and CRC.METHODSWe frst identifed the expression levels and methylation levels of FMN2 in large-scale human CRC expression data-sets, including GEO and TCGA, and analyzed the relation-ship between the expression and methylation levels. Then, the methylation levels in four CpG regions adjacent to the FMN2 promoter were assessed by MethylTarget？ assays in CRC cells and in paired colorectal tumor samples and adjacent nontumor tissue samples. Furthermore, we inhibited DNA methylation in CRC cells with 5-Aza-2’-deoxycytidine and assessed the expression of FMN2 by qRT-PCR. Last, the association between FMN2 methylation patterns and clinical indicators was analyzed.RESULTSA statistically significant downregulation of FMN2 ex-pression in large-scale human CRC expression datasets was found. Subsequent analysis showed that a high frequency of hypermethylation occurred in the FMN2 gene promoter in CRC tissues; operating characteristic curve analysis revealed that FMN2 gene methylation had a good capability for discriminating between CRC and nontumor tissue samples （AUC = 0.8432, P 〈 0.0001）. MethylTarget？ assays showed that CRC cells and tissues displayed higher methylation of these CpG regions than nontumor tissue samples. Correlation analysis showed a strong inverse correlation between methylation and FMN2 expression, and the inhibition of DNA methylation with 5-Aza significantly increased endogenous FMN2 expression. Analysis of the association between FMN2 methylation patterns and clinical indicators showed that FMN2 methylation was signifcantly associated with age, N stage, lymphovascular invasion, and pathologic tumor stage. Notably, the highest methylation of FMN2 occurred in tissues from cases of early-stage CRC, including cases with no regional lymph node metastasis （N0）, cases in stages Ⅰ and Ⅱ, and cases with no lymphovascular inva-sion, but the methylation level began to decrease with tumor progression. Additionally, FMN2 promoter hyper-methylation was more common in patients 〉 60 years old and in colon cancer tissue.CONCLUSIONFMN2 promoter hypermethylation may be an important early event in CRC, most likely playing a critical role in cancer initiation, and can serve as an ideal diagnostic biomarker in elderly patients with early-stage colon cancer.

Vulnerability assessment of water resources to climate change in Chinese cities

Climate change is an inevitable trend,which challenges security of water resources in China,especially in cities.Assessing vulnerability of water resource to climate change in cities has important role for policy makers. The paper constructs a vulnerability function,including exposure,sensitivity and adaptive capacity,according to the vulnerability concept proposed by IPCC,establishes an assessment indicators system of water resources to climate change in cities,and analyzes vulnerability features of Chinese cites based on 655 cities＇data in 2006.The vulnerability assessment results show that there are distinctive differences among all the cities,between east,central and west cities,between ordinary,big and mega cities,while there is no statistical significant difference between north and south cities.Based on the research,the paper suggests that strategic emphasis should focus on the central cities and ordinary cities

The Impacts of the Interannual Variability of Vegetation on the Interannual Variability of Global Evapotranspiration: A Modeling Study

The impact of the interannual variability (IAV) of vegetation on the IAV of evapotranspiration is investigated with the Community Land Model (CLM3.0) and modified Dynamic Global Vegetation Model (DGVM). Two sets of 50-year off-line simulations are used in this study. The simulations begin with the same initial surface-water and heat states and are driven by the same atmospheric forcing data. The vegetation exhibits interannual variability in one simulation but not in the other simulation. However, the climatological means for the vegetation are the same. The IAV of the 50-year annual total evapotranspiration and its three partitions (ground evaporation, canopy evaporation, and transpiration) are analyzed. The global distribution of the evapotranspiration IAV and the statistics of evapotranspiration and its components in different ecosystems show that the IAV of ground evaporation is generally large in areas dominated by grass and deciduous trees, whereas the IAV of canopy evaporation and transpiration is large in areas dominated by bare soil and shrubs. For ground evaporation, canopy evaporation, and transpiration, the changes in IAV are larger than the mean state over most grasslands and shrublands. The study of two sites with the same IAV in the leaf area index (LAI) shows that the component with the smaller contribution to the total evapotranspiration is more sensitive to the IAV of vegetation. The IAV of the three components of evapotranspiration increases with the IAV of the fractional coverage (FC) and the LAI. The ground evaporation IAV shows the greatest increase, whereas the canopy evaporation shows the smallest increase.

Deduction and Validation of an Eulerian-Eulerian Model for Turbulent Dilute Two-Phase Flows by Means of the Phase Indicator Function-Disperse Elements Probability Density Function

A statistical formalism overcoming some conceptual and practical difficulties arising in existing two-phase flow (2PHF) mathematical modelling has been applied to propose a model for dilute 2PHF turbulent Hows. Phase interaction terms with a clear physical meaning enter the equations and the formalism provides some guidelines for the avoidance of closure assumptions or the rational approximation of these terms. Continuous phase averaged continuity, momentum, turbulent kinetic energy and turbulence dissipation rate equations have been rigorously and systematically obtained in a single step. These equations display a structure similar to that for single-phase flows. It is also assumed that dispersed phase dynamics is well described by a probability density function (pdf) equation and Eulerian continuity, momentum and fluctuating kinetic energy equations for the dispersed phase are deduced. An extension of the standard k-e turbulence model for the continuous phase is used. A gradient transport model is adopted for the dispersed phase fluctuating fluxes of momentum and kinetic energy at the non-colliding, large inertia limit. This model is then used to predict the behaviour of three axisymmetric turbulent jets of air laden with solid particles varying in size and concentration. Qualitative and quantitative numerical predictions compare reasonably well with the three different sets of experimental results, studying the influence of particle size, loading ratio and flow confinement velocity.

Some remarks on the dynamical conformity of rock joints

A recently developed computerized method for assessing the rock joint coefficients is discussed. The performances of formerly introduced relative similarity indicators, along with the correlation coefficient, are subjected to critical analysis. These relative numerical indicators are replaced by two absolute indicators whose properties better describe surface textures of rock joints. The first absolute indicator results from the Fourier Matrix and evaluates wavy shapes of surfaces. The second absolute indicator quantifies the heights of surface reliefs, and is defined as the root mean square height of the surface outline. The behavior of the newly introduced numerical indicators are investigated by means of the deterministic periodic surface reliefs. The practical application of the new indicators is presented and the convenient performances of both the indicators are documented.

Photoelectric Instrument for Measuring the Geometrical Dimensions of the Bullet

A laser-scanning calibre measuring and digital indicating grating photosensor gauging systems are introduced,which are used to measure the dimensions of bullet.In the paper,we expound the operation principle and design idea of the principal parts and units.

The Study on the Economic Application of Financial Big Data

Big Data has become the focus of the Internet industry. With the development of various industries becoming more sophisticated, long-term accumulation of operational data, customer data displays exponential growth trend. The rapid development of financial big data both poses opportunities and challenges for financial industry and economic growth. This article explains the economic application of big data based on the perspective of economics.

Exploring Individual Lifetime Wellbeing： An Optimal Year of Birth

This paper aims to explore the concept of wellbeing from an individual＇s perspective. Current indicators of wellbeing [including economic indicators such as Gross Domestic Product （GDP）] are static indicators--they take into account issues as they are in a given period of time such as the current year. However, these indicators fail to measure the sense of wellbeing felt by an individual over a lifetime, and therefore could miss important issues of relevance when developing policy and other interventions to improve wellbeing. Various wellbeing indicators for the OK over the period of 1945-2013 are explored. These indicators are used to develop a ＂lifetime wellbeing＂ measure. The indicators are grouped and predictions of indicators into the future are made. The data show that some indicators have peaked and are now in decline. Therefore, under a certain choice of indicators and weightings, it is possible to maximise wellbeing over a person＇s lifetime meaning, there may have been an optimum year in which to be born.

The Diversity of the Environmental Impact in Kurzeme

The analysis of environmental impact effects on forest ecosystems has a theoretical and practical nature. Many methods have been developed to determine characteristics and intensity of this impact. Methodologically, they can be divided into three groups： environmental parameter, bioindicative and combined methods. To evaluate the environmental impact a combined method was used in this study, it was based on trees as the bioindicators and their response reactions, and environmental parameter analysis. In this study the bioindicator was Norway spruce （Picea abies （L.） Karst.）, whose response reaction was used to explain total impact volumes of environmental factors in different places in the region of Kurzeme and try to interpret the causes of these differences. As the bioindicators criterion was used response reaction of Norway spruce during a period of 20 years, which was expressed with cumulative and annual additional volume increment, and was depending on the location of the stand and its morphometric characteristics. The empirical material was collected in Kurzeme region in 28 sample plots that are located on two transects and in one reference stand. For the evaluation the widths of the last 40 year growth rings were measured. To express the environmental impact in Kurzeme region a multiple regression model was developed, which explains the environmental impact in the volume of 68.2%, the rest part can be explained by the local conditions of each stand. It must be noted that methodology used in this study is very sensitive, thus, each of the nuances in the dynamics of volume＇s annual reduced additional increments has biological and ecological cause.