Distribution Of Various Forms Research Articles

Distributionally-Informed Recommender System Evaluation

Current practice for evaluating recommender systems typically focuses on point estimates of user-oriented effectiveness metrics or business metrics, sometimes combined with additional metrics for considerations such as diversity and novelty. In this article, we argue for the need for researchers and practitioners to attend more closely to various distributions that arise from a recommender system (or other information access system) and the sources of uncertainty that lead to these distributions. One immediate implication of our argument is that both researchers and practitioners must report and examine more thoroughly the distribution of utility between and within different stakeholder groups. However, distributions of various forms arise in many more aspects of the recommender systems experimental process, and distributional thinking has substantial ramifications for how we design, evaluate, and present recommender systems evaluation and research results. Leveraging and emphasizing distributions in the evaluation of recommender systems is a necessary step to ensure that the systems provide appropriate and equitably distributed benefit to the people they affect.

СОЕДИНЕНИЯ АЗОТА И ФОСФОРА В ВОДНЫХ ОБЪЕКТАХ КАЗАХСТАНСКОЙ ЧАСТИ БАССЕЙНА Р. ИРТЫШ

We present materials from our research to study the distribution of various forms of mineral nitrogen and phosphorus in the Irtysh River basin in the summer of 2023. It has been established that the content of mineral forms of nitrogen and their ratios are not the same in the water of rivers and lakes. In the water of the river’s tributaries. The Irtysh River was dominated by nitrate ions (from 0.039 to 1.033 mgN/dm3), with a maximum in the right-bank tributaries. The nitrite and ammonium ions share accounted for 2.7, 32.7 and 15.3, 38.3% of the total nitrogen, respectively. The share of nitrates in the Black Irtysh River averaged 59% of the amount of nitrogen. Downstream, within the Pavlodar region, nitrates were more often absent, and the proportion of ammonium nitrogen increased. Mineral soluble phosphorus (phosphate ions) was found in the water of all surveyed areas of the basin in insignificant concentrations (0.015 – 0.130 mg/dm3) due to the low solubility of its compounds and intensive absorption by hydrobionts. From the upper to the lower sections of the Irtysh there was a slight increase in the concentration of nitrogen and phosphorus compounds, as a result of the influence of the anthropogenic factor.

Humor of Canadian Ukrainians: After the Diaspora Editions (the 1910s – 1980s)

The article is an attempt to describe the peculiarities of the laughing culture and humor of Ukrainians in Canada (1910s – 1980s – the first – fourth waves of emigration) as one of the important factors in the preservation of national identity, traditions of folk culture, indicators of the reflection of the sociology of Ukrainian immigrants and their descendants, the dynamics of the communication field of the diaspora community, transformation of Ukrainian language in the multicultural environment of Canada, which is reflected in humorous speech and other creative genres. A review (on a selective basis) of the works of the representatives of the humorous workshop, which has been imprinted on the pages of diaspora editions of Canadian Ukrainians (magazines, calendars, calendar-almanacs), providing their space for published works, promulgation, distribution of various forms of laughing culture and folk humor is known as a testimony (generated in a word) of the immortality of the Ukrainians national culture. Ukrainian humor, which occupies its niche in the linguistic picture of the world, is considered as a reaction of the linguistic personality-immigrant on the social and cultural processes of the English-speaking surroundings. The materials submitted in this article reflect Ukrainian humor – very emotional, sharp, witty, snarky, and from time to time – ironically-sad, merciless to oneself as an individual, but never angry, not poisonous, not such as to degrade human dignity of a stranger – this is the eternal height of the ethnic culture of the people, its worldview, outlook, philosophy. A unique cultural and historical phenomena of preservation of the national culture of their historical homeland, its peculiarities, traditions, and mentality by Ukrainians of Canada is described in the light of the Institute of Laughter Culture, the space of which includes not only the printed word, stage art, but also ethnic choreography, musical and artistic works. Applying the methodology of a whole range of humanitarian disciplines, a section of the history and development of social communications in the immigrant surroundings is investigated from the point of view of one, but multifaceted and multi-colored factor – folk humor, the change of the Ukrainian folklore complex; the speed of integration into the English-speaking culture and the inevitable objectivity of this process and ability of the immigrant community to comprehend and perceive creatively the influence of other cultures of multicultural Canada, but at the same time, to resist acculturation, the absorption of its ancient culture. The problem hasn’t been investigated in science, in particular, in history, in Slavic folkloristics, in such a formulation.

Prevalence and patterns of anthropometric failure among under-five children in Nigeria: Evidence from the National nutrition and health survey, 2018.

Globally, malnutrition among under-five children remains a public health concern. There is increasing concern at research and policy levels about anthropometric failure and the double burden of child malnutrition across different groups of children. The objective of this study was to describe the magnitude and distribution of various forms of anthropometric failure (AF) among children under age five in Nigeria. We used the 2018 National Nutrition and Health Survey data collected among 19,471 under-five children in Nigeria. The most prevalent AF was stunting only (17.7%) followed by stunting and underweight (13.9%). Wasting, stunting and underweight was found among 3.5% of the sample. Wasting, stunting and underweight was most common in age 6-11 months (7.0%) and 12-23 months (6.9%). Overall, about 1 out of 5 under-five children has multiple anthropometric failure. The peak age group for multiple AFs was between six months and 35 months. Multiple AF was less likely among females compared to males (RR=0.74, CI: 0.69, 0.80). The risk of multiple AF was higher in both North East (RR=2.15, CI: 1.78, 2.59) and North West (RR=2.98, CI: 2.51, 3.55) relative to the North Central. In contrast, the risk was lesser in the South East (RR=0.75, CI: 0.59, 0.95) and other southern regions. The study showed that multiple anthropometric failure is a common problem among children in Nigeria. Programmes that will support prevention and early identification of different types of malnutrition among under-five children across States in Nigeria are recommended.

INVESTIGATION OF DEPORTMENT OF CHALCOPHILIC HEAVY METALS IN THE WASTE ROCK OF CENTRAL COAL ENRICHMENT PLANT "CHERVONOHRADSKA" FOR THE PURPOSES OF ENVIRONMENTAL SAFETY OF LVIV-VOLYN COAL BASIN

Iryna Kochmar Vasyl Karabyn 1 Lviv State University of Life Safety 2Lviv State University of Life Safety Mining areas are centres of increased environmental danger. This is due to the development and operation of mines and subsequent beneficiation of coal, as well as the storage of significant volumes of empty waste rock in landfills. An important component of ensuring environmental safety is the investigation of the factors and ways of the impact of rock dumps on the state of the environment. In this regard, the article examines the forms of heavy metals found in the rock of the waste heap of the central coal enrichment plant "Chervonohradska" of the Lviv-Volyn coal basin. The environmental hazard factors caused by the distribution of various forms of lead, cadmium, zinc, and copper, based on establishing the migration capabilities of these elements in the technogenesis zone, are analyzed. It was determined that the gross content of lead reaches 16.32 mg/kg, cadmium – 5.84 mg/kg (exceeding clarke up to 29.2 times in siliceous siltstone and siltstone), zinc – 421 mg/kg (exceeding clarke up to 5.26 times in sandstone, siltstone and siliceous siltstone), copper – 112.89 mg/kg (exceeding clarke by 2 times in siltstone). The concentration coefficients of heavy metals in the samples were determined in relation to the gross form. The results of the research give a reason to evaluate the rocks of the waste dump in terms of the distribution of various forms of Pb, Cd, Zn and Cu as dangerous for the environment and unsuitable for use because in all the samples an excess content was observed in one form or another.

Effect of particle mass inhomogeneity on the two-dimensional Rayleigh–Bénard system of Yukawa liquids: A molecular dynamics study

The effect of particle mass inhomogeneity on the evolution of macroscale fluid flow in the Rayleigh–Bénard system of two-dimensional Yukawa liquids is studied using “first principles” classical molecular dynamics simulations. We find that Rayleigh–Bénard convection cells (RBCCs) formed in the quasi-steady-state become unstable at later times as a result of introducing a small fraction (≤2% of the total particles) of particle mass inhomogeneity in a Yukawa system made up of point particles of uniform charges. The unstable RBCCs, after passing through several intermediate states, give rise to a unidirectional shear flow in the direction perpendicular to the external gravity. Depending on the fraction and phase space of the particle mass inhomogeneity introduced in the system, the unidirectional shear flow further evolves to give shearless parallel flow. We use single or dual particle mass distributions of various forms, such as Gaussian distribution, Dirac-delta distribution, or a combination of both, around different mean values in order to introduce particle mass inhomogeneity. The role of system size on the emergence of various intermediate fluid flow states is also investigated. Furthermore, by introducing an inhomogeneity in charge commensurate with mass inhomogeneity, we demonstrate the robustness of our findings. Finally, for the case of decreasing correlation strength and for otherwise identical parameters, it is shown that the particle mass inhomogeneity fails to generate shear flows from RBCCs in 2D Yukawa liquids.

Agro-ecological system and its significance to social security in small-island communities of the Central Maluku, Eastern Indonesia

Local communities in central Maluku have constructed their agro-ecology, from settlement to forest, with particular plants and patterns. This terrestrial ecosystem has been gone along with a production of certain social institutions based on the understanding of their environment and resource use. This paper shows how the local agro-ecological system has been an effective strategy for ecological adaptation and environmental management of small island environment. The system of agro-ecology illustrates a significant temporal and spatial distribution of various forms of land use, reflecting the interconnectedness of natural resource management and local social security. Varied cultural rules and practices on system of agro-ecology demonstrate the role of different units that support local ecology as well as social security of kin-groups. The paper also shows how recent agricultural, socio-economic and cultural changes have shaped the adaptation and strategies, and how present trends of the ethno-ecological zones affect human-environment relations and community relations and livelihoods which in turn also affect local social security.

Spatial distribution of various forms of malnutrition among reproductive age women in Nepal: A Bayesian geoadditive quantile regression approach.

Addressing both the under-and over-nutritional status of women is an eminent challenge for developing countries like Nepal. This paper examined a critical analysis of factors associated with various forms of malnutrition using Bayesian geoadditive quantile regression approach and assessed spatial variations of malnutrition among Nepalese women using Asian cut-off values. Data drawn from the 2016 Nepal Demographic and Health Survey was utilized to assess the spatial distributions of underweight, overweight and obesity at the provincial level. Spatial and nonlinear components were estimated using Markov random fields and Bayesian P-splines, respectively. The analysis of 4,338 women confirmed that women living in extremely urbanized areas and in Province 1, Province 3, and Province 4 were more likely to be overweight/obese. Similarly, the likelihood of being underweight was prominently high among women residing in rural municipality and women residing in Province 2 and Province 7. Women from the richest and richer quintiles, and with primary education were more likely to be obese. Furthermore, currently-working women and women having access to protected water source were less likely to be obese while improved toilet and access to electricity facility were associated with obesity. Women with access to newspaper and radio were less prone to obesity. Inconsistent distribution of under- and over-nutrition existed in Nepal, given that the high prevalence of overweight/obesity among women living in metropolitan and undernutrition among rural women. Specific intervention measures, addressing location-specific nutrition issues are urgent. Rigorous implementation of strategies incorporated in the national nutrition plan is called for to curb the burden of overweight/obesity. Involving mass media to promote healthier lifestyle and nutritious food could be advantageous at the population level, especially in rural municipalities.

鹭鸟栖息对杭州湾湿地土壤磷累积及形态分布的影响

土壤中磷含量对维持生态系统平衡起着重要作用。为研究杭州湾湿地迁徙候鸟栖息以及鸟粪的输入对栖息地土壤生态环境的影响，开展了鹭鸟筑巢树林下（影响区）和无鹭鸟筑巢树林下（对照区）土壤磷累积、土壤及鸟粪磷形态分布研究。结果表明：鹭鸟影响区土壤有机碳（Soil Organic Carbon，SOC）、全氮（Total Nitrogen，TN）、全磷（Total Phosphorus，TP）、有效磷（Available Phosphorus，AP）含量显著高于对照区（P<0.05）；对照区土壤TP含量为718.33 mg/kg，影响区土壤TP平均含量最高可达2040 mg/kg，其中钙结合态磷（Ca-bound P，Ca-P）含量最高，约占55.22%-62.96%，其次是残渣态磷（Residual Phosphorus，RP）、有机磷（Organic Phosphorus，OP）、铁铝结合态磷（Fe/Al-bound P，（Al+Fe）-P））、交换态磷（Exchangeable P，Exch-P）。鸟粪中有机碳（Organic Carbon，OC）、TN、TP含量分别是表层土壤的11.18-40.90倍，94.22-148.11倍，15.41-43.22倍，差异极显著（P<0.01）。TP含量与Exch-P、（Fe+Al）-P、Ca-P、AP极显著正相关，与RP显著正相关，与pH显著负相关。结果表明鸟粪输入使杭州湾湿地土壤TP含量显著提高，Exch-P、（Fe+Al）-P、Ca-P、AP含量均有提高，且占TP百分比增大，鸟粪输入造成了该地土壤磷素累积的同时增加了土壤磷素的流失风险。;The content of phosphorus in soil plays an important role in maintaining the balance of the ecosystem. In order to study the impact of migratory birds inhabiting and dropping guano on the soil ecological environment in Hangzhou Bay wetland, the research of phosphorus accumulation and distribution of various forms of phosphorus in soil and guano was carried out in the area with or without egrets inhabiting (affected area and controlled area). The results showed that the content of Soil Organic Carbon (SOC), Total Nitrogen (TN), Total Phosphorus (TP) and Available Phosphorus (AP) in the egrets effecting area was significantly higher than that in the controlled area (P<0.05). The soil TP content in the controlled area was 718.33 mg/kg, which was up to 2040 mg/kg in the affected area. The content of Ca-bound P (Ca-P) rank first among all these forms of phosphorus, accounting for about 55.22—62.96%, followed by Residual Phosphorus (RP), Organic Phosphorus (OP), Fe/Al-bound P ((Fe+Al)-P) and Exchangeable P (Exch-P). The contents of Organic Carbon (OC), TN, and TP in guano were 11.18—40.90 times, 94.22—148.11 times and 15.41—43.22 times of the soil, showing significant difference (P<0.01). TP content showed extremely significantly positive correlations with Exch-P, (Fe+Al)-P, Ca-P, AP, significantly positively correlated with RP, while significantly negatively correlated with pH. Generally, the content of TP in soil of Hangzhou Bay wetland was significantly increased due to guano input. The content of Exch-P, (Fe+Al)-P, Ca-P and AP were all increased, so as the percentages of them did in TP. Input of guano caused the accumulation of phosphorus in the soil which increased the risk of phosphorus loss from the soil, as well.

We Need to Talk About Racism-In All of Its Forms-To Understand COVID-19 Disparities.

Purpose: Racism is an essential factor to understand racial health disparities in infection and mortality due to COVID-19 and must be thoroughly integrated into any successful public health response. But highlighting the effect of racism generally does not go far enough toward understanding racial/ethnic health disparities or advocating for change; we must interrogate the various forms of racism in the United States, including behaviors and practices that are not recognized by many as racism.Methods: In this article, we explore the prevalence and demographic distribution of various forms of racism in the United States and how these diverse racial ideologies are potentially associated with racialized responses to the COVID-19 crisis.Results: We find that among white Americans, more than a quarter express traditional racist attitudes, whereas more than half endorse more contemporary and implicit forms of racist ideology. Each of these types of racism helps us explain profound disparities related to COVID-19.Conclusions: Despite a robust literature documenting persistent patterns of racial disparities in the United States, a focus on the role that various forms of racism play in perpetuating these disparities is absent. These distinctions are essential to realizing health equity and countering disparities in COVID-19 and other health outcomes among people of color in the United States.

River companies of Ob-Irtysh water basin (1860-1918): forms of pool of capital

The relevance of this research consists in the fact that modern historical literature describes an overall picture of evolution of business companies, although prevalence and peculiarities of organizational-legal form demonstrates the level of development of economic relations in the Russian Empire in a time of capitalist modernization. The subject of this research is the organizational-legal forms of river companies of Ob-Irtysh water basin over the period from 1860 to 1918 as an independent factor in development pf capitalist relations. The goal of this work is to determine the main forms of organization of river companies of Ob-Irtysh water basin, considering attraction of family and &amp;ldquo;borrowed&amp;rdquo; capital. In the course of this research, the author applied the method of modeling of commodity-money relations of Ob-Irtysh water basin, which allowed revealing the dynamics and specific characteristics of development of entrepreneurship in a separate region. The method of historical-comparative analysis illustrated the trends of choice of one or another form of pool of capital, considering the combination of family, geographical, economic, social and administrative aspects. The research results display the dynamics of distribution of various forms of business companies in the sphere of river transportation in Ob-Irtysh water basin, which describes a more objective picture of commodity-money relations in Western Siberia. The presented materials can be utilized in studying particular business companies of Ob-Irtysh river system as an institutional paradigm. The scientific novelty and conclusions lie in determination of the forms of organization of river companies of Ob-Irtysh water basin in accordance with the Russian legislation. This allows tracing the dynamic of emergence of steamship companies due to retention of strong influence of family ties in the business world.

The Established and the Delegated: The Division of Labour of Domination among Effective Agents on the Field of Power in Denmark

What is the relationship between the various forms of power held by elites in contemporary society? Using Bourdieu’s notion of the field of power, we address this question by exploring the division of labour of domination among contemporary Danish elites. Via a specific multiple correspondence analysis of 44 variables with 198 categories, we examine the relationship between the volume and distribution of various forms of capital held by 423 individuals at the core of Danish elite networks, arguing that they constitute effective agents in the field of power. We find three major differentiations between: (1) established and newcomers; (2) public and private forms of legitimation; and (3) rural or industrial-based, but nonetheless organisationally well connected, elites and the social elite surrounding Copenhagen state nobility. The legitimising pole of the field of power does not necessarily derive its positions from the cultural field but can also rely on delegated forms of capital.

The content and distribution of various forms of carbon in urban soils of southern Russia on the example of Rostov agglomeration

The content and distribution of organic and inorganic carbon in soils of Rostov agglomeration were studied. The results obtained by the direct method of combustion catalytic oxidation on a TOC-L CPN Shimadzu carbon analyzer and by the indirect method of wet combustion of organic compounds were compared. The difference in the carbon contents obtained by these methods was the greatest in the root-saturated sod horizons, where it varied from 0.02 to 0.67%; in the humus-accumulative horizons, it did not exceed 0.12%. Generally higher values were obtained by the method of catalytic combustion.In the light-humus A b horizon of the soils buried under the urbic stratum, a statistically reliable decrease in the organic carbon content in comparison with that in the A horizon of the natural surface soils was observed. Middle-profile carbonate-accumulative horizons of the buried and surface soils (B b and B) were characterized by approximately similar contents of both organic and inorganic carbon attesting to the low anthropogenic influence on these horizons. The lower (C) horizons of the buried and surface soils reliably differed in the contents of inorganic carbon, which was higher in the natural surface soils.Data on the diagnostic urbic horizons were conditionally divided into two clusters of sandy and clay horizons. However, this attempt to arrange the results of the organic carbon measurements did not show any definite regularity in the distribution of organic carbon in the urbic horizons because of the high variability of this indicator.

Pedogenic Forms of Iron in Soils Developed from Four Parent Materials

Information on the distribution of various forms of iron in soils are valuable in the study of soil genesis. The objective of this study was to to evaluate the pedogenic forms of iron in soils developed over basement complex and basaltic parent materials of the study area. Geologic units considered in the basement complex area were granite gneiss, biotite granite and migmatite. Stratified random sampling formed the basis for field work. Soil sampling was carried out by digging at least two soil profile pits in each geologic unit. Organically bound, amourphous and total iron oxides were estimated using 0.1 M sodium pyrophosphate, acidified (pH 3) ammonium oxalate, and dithionite-citrate-bicarbonate method, respectively. The total Fe in the soil samples were determined after a mixed acid digestion. In general, total iron fractions were statistically similar among the soils of basement complex geologic units but significantly lower than those of soils derived from basaltic rocks. However, the distribution of iron oxide fractions was similar among the basement and basaltic geologic units. Furthermore, there were significant differences in the distribution of iron oxides in the B horizons of basement complex derived soils. Consequently, the quantity of iron oxides in the B horizon was in the order migmatite &gt; biotite granite &gt; granite gneiss. About 70% of total iron oxides in the soils over granite gneiss, biotite granite and basaltic rocks was amorphous in nature. Furthermore, total iron oxides constitute less than 20% of total clay both in the basement complex and basaltic soils.

On the Genealogy of Kokujin: Critical Thinking about the Formation of Bankoku and Modern Japanese Perceptions of Blackness

ABSTRACTThis article examines how Japanese perceptions of blackness and modern knowledge about bankoku (myriad lands) were formed in early modern Japan. From about the mid-seventeenth century until the mid-nineteenth century, Japanese intellectuals absorbed the Western sciences, technology, and medicine through contact with the Dutch in Nagasaki. This field of study is called rangaku (Dutch studies). In this context, the Japanese intellectuals expanded their knowledge about the world – specifically, geographical spaces and numerous races. During this process, they shaped their ethnic and racial stereotypes, including racist ones about black Africans. The idea of black inferiority became deeply embedded into Japanese geographical and anthropological knowledge. I use Michel Foucault’s idea of ‘genealogy’ as an analytical framework for a diagnosis of the current condition. My genealogical investigation of the concept of kokujin (blacks) reveals the historical processes in which Japan’s indigenous, pre-contact sangoku (three-land) cosmology became invalidated and marginalized from modernist discourses on bankoku. This approach enables a critique of modernity itself, which has been associated for centuries with global distributions of various forms of Western knowledge and power – those upon which our present-day practices and discourses still depend.

Modeling fiber arrangement and distribution during the roller drafting process

During the spinning process, the roller drafting operation plays a significant role in attenuating the sliver to an appropriate linear density. In this study, the model of fiber arrangement was applied to simulating the roller drafting process in order to shed light on the sliver dynamic behavior in the drafting zone. The drafting process was operated from the high-velocity motion of the first accelerated fiber to the high-velocity motion of the last accelerated fiber. The proposed model showed that the simulated sliver attenuation processes were highly corresponded to the actual sliver attenuation results. In addition, the results revealed that the draft ratio, gauge length, input sliver linear density and accelerated-point distribution form had effective influences on the attenuation curves of sliver linear density, whilst the delivery speed scarcely had any effect. The fiber distributions of various forms were also investigated specifically and quantitatively from the fiber arrangement during the drafting procedure in real time. Furthermore, the sliver dynamic was also described by the mean and CV of fiber velocities within the drafting zone. The obtained simulation results demonstrated that the draft ratio, gauge length and delivery speed had a bearing on the mean velocity of fibers, while the CV of fiber velocities was significantly influenced by the draft ratio, gauge length and input sliver linear density. Besides, the distribution pattern has a valuable contribution to the mean and CV of fiber velocities. In consequence, the new drafting model was validated to be effective in quantizing the drafting process.

ASSESSMENT OF CAPITAL FLOWS BETWEEN THE EAEU MEMBER STATES AND OTHER REGIONAL ECONOMIC ASSOCIATIONS

Over the past decade, the importance of so-called collective investments has grown in the world economy, especially in OECD countries. Such investments are made through investment companies, mutual funds, fund and investment trust companies. OECD member countries have formed a unified system for regulating collective investment, the purpose of which is to create common investment conditions for all member countries of this organization. This article studies the evolution of the geographical distribution of various forms of international capital flows, from the point of view of deepening regional cooperation, as well as their structural features, which can serve as a basis for assessing the effectiveness of capital investments and the features of economic development in individual regions, particularly in the EАEU countries.

Environmental significance of phosphorus existing forms in the sediments of Yuqiao Reservoir in Tianjin

研究天津于桥水库沉积物中磷形态的空间分布特征和垂直分布特征对了解水源型水库富营养化现状及其过程具有重要的现实意义.利用抓斗式采泥器及柱状采泥器分别采集表层沉积物样品及柱状沉积物样品，采用Psenner提出的连续提取法对沉积物磷形态进行分级测定，揭示整个水库沉积物各形态磷的空间分布特征以及不同区域垂直方向上的分布规律.结果表明：于桥水库表层沉积物总磷（TP）含量为303.7~997.8 mg/kg，各形态磷含量大小顺序依次为：钙结合态磷（Ca-P） > 铁结合态磷（Fe-P） > 残渣态磷（Res-P） > 铝结合态磷（Al-P） > 有机态磷（Org-P） > 可交换态磷（Ex-P）.表层沉积物中Fe-P、Al-P、Ca-P与TP含量由东至西逐渐递减，主要受到黎河河水夹带的外源性磷输入的影响；Res-P含量由东至西逐渐递增，与活性磷的分布规律相反，表明水库下游比上游的水质更好.垂直分布上，南部区域底层与表层沉积物相差不大，说明从1960s以来磷的沉积量就比较大；西部区域沉积物中Fe-P和Org-P含量较高，随深度的增加有明显降低的趋势；中心区域的各形态磷和TP含量均较低，且随着深度增加逐渐降低，现阶段沉积物中的磷以滞留为主，释放潜力较小.;It is of great significance to study the status of eutrophication and its process in water source reservoirs by analyzing the spatial and vertical distribution characteristics of phosphorus forms in the sediment of Yuqiao Reservoir in Tianjin. The samples of surface sediments and sediment cores were collected by grab-type sampler and column-type sampler, respectively, and the phosphorus forms of sediments were analyzed by continuous extraction method proposed by Psenner, in order to reveal the spatial distribution of various forms of phosphorus in the reservoir, as well as the distribution in the vertical direction of different regions. The results showed:The contents of total phosphorus in the surface sediments of Yuqiao Reservoir were 303.7-997.8 mg/kg, and the order of the mass fraction of phosphorus forms was:Ca-P > Fe-P > Res-P > Al-P > Org-P > Ex-P. The Fe-P, Al-P, Ca-P and TP in the surface sediments gradually decreased from east to west, mainly affected by the input of exogenous phosphorus entrained by the Lihe River. The Res-P is gradually increasing from east to west, contrary to the distribution of active phosphorus, indicating that the water quality in the downstream of the reservoir is better than that in the upstream. For the vertical distribution, there is little difference between the bottom sediments and the surface sediments in the southern region, which indicates that the deposition amount of phosphorus is relatively large since the 1960s; and the Fe-P and Org-P contents in the western sediments are higher, and the trend is significantly reduced as the depth increases. The various forms of phosphorus and TP contents in the central area are almost the lowest, and gradually decrease with the depth, phosphorus in the sediments at this stage is mainly retained with small release potential.

Violence in Schools: Repeat Victimization, Low Self-Control, and the Mitigating Influence of School Efficacy

Objectives Examine the distribution of various forms of violent victimization among adolescents in school and the main and interactive effects of low self-control and school efficacy on repeat assault victimization.

Quantitative distribution of phytoliths as reliable diagnostical criteria of ancient arable lands

Abstract People ploughed the soils in the central part of Russia for at least two thousand years, based on historical documents and archaeological artifacts. However, we cannot find any traces of ancient arable land, because after a 200–250 year uncultivated period, all morphological and chemical properties have disappeared. Two soils near Moscow (Russia) were studied: buried and modern. The first soil was under an 800-year-old burial mound and the second one was nearby. It seemed that modern soil was also tilled in the past, but nothing in morphology and chemical properties indicated that. We used phytolith analysis to investigate if a typical arable distribution of phytoliths has been preserved in the soil after an 800 year uncultivated period. The ancient plough layer has been completely transformed within the past 700–800 years. Its smooth lower boundary has totally disappeared and its chemical characteristics have changed, including the reaction of soil solution, organic matter distribution, content and distribution of various forms of iron. It is possible to distinguish some stable indicators of ploughing, which have weakly changed even after a period of 700–800 years, and allow us to interpret the ancient land use. Such indicators include the distribution of bulk phosphorus. While the native soils show an accumulative trend with maximal concentration of total phosphorus within the sod horizon, the arable soils are characterized by a uniform level of total phosphorus throughout the plough layer and, in some cases, also enrichment in this element along the former plough line (lower boundary of plough horizon). The other relatively stable indicator is the clay distribution pattern. The eluvial–illuvial distribution pattern is preserved in both buried and modern soils. During the arable period of land use, a special pattern of phytolith distribution was formed within the upper part of the soil, with the maximum concentration of phytoliths along the plough line. This pattern has been preserved for hundreds of years with only a slightly smoothened shape. Therefore, the quantitative distribution of phytoliths within a soil profile is a stable indicator that can serve as a reliable diagnostic feature of ancient arable stages, even when all other diagnostic indicators are absent. The presence of phytoliths from cultivated cereal crops (dendritic form) within the upper layer is an additional confirmation of the former arable use of the soil.