The Class Size Controversy

[Excerpt] When we ask whether class size matters for achievement, it is essential to ask also, how class size matters. This is important for three reasons. First, if we can observe not only achievement differences, but also the mechanisms through which the differences are produced, this will increase our confidence that the differences are real, and not an artifact of some unmeasured or inadequately controlled condition. Second, the effects of class size may vary in different circumstances, and identifying how class size affects achievement will help us to understand why the effects of class size are variable. Third, the potential benefits of class size reduction may be greater than what we observe. For example, suppose class size reductions aid achievement, but only when teachers modify instructional practices to take advantage of the smaller classes. If a few teachers make such modifications, but most do not, then understanding how class size affects achievement in some cases will help reveal its potential effects, even if the potential is generally unrealized

Grazing Effects on Genetic Diversity of \u3cem\u3eFestuca Campestris\u3c/em\u3e Rydb. And \u3cem\u3eStipa Grandis\u3c/em\u3e L. On the Native Grasslands in Canada and China, Respectively

Genetic drift or selectively neutral mutation in finite populations may result in genetic diversity within a natural population (Kimura, 1986). Genetic diversity influences the resilience of a species to survive perturbations or adapt to changes in its environment. Grazing by livestock may affect genetic diversity by exerting selection pressure on grazing sensitive species. In this study, we examine the effects of heavy sustained grazing pressure on the genetic diversity of Festuca campestris Rydb. and Stipa grandis L. These species are found on the Canadian Plains and the steppes of Inner Mongolia, respectively. Each is an important forage species that dominates their respective grasslands but decline readily when subjected to heavy grazing pressure

Strategic Alliances for Technology Adoption: Alliances and Partnerships for Blockchain Adoption

This paper aims to study the relevance and importance of strategic alliances for emerging technology adoption. The case researched and discussed here is Blockchain adoption in the semiconductor industry. As a technology, Blockchain has been around for over a decade and is known to provide tremendous value in business transactions. However, the adoption has not gained traction mainly due to the fact that it takes a network to adopt an industrial Blockchain and cannot work in silos. Most companies are shying away from it as they haven\u27t explored what makes a successful strategy for adoption. A literature review was done on the similar technology adoption in the past. The nature of Blockchain and its network dependency were considered. It was clear that strategic alliances are the way to move forward. The various aspects to be considered while forming an alliance, such as understanding the core competencies, finding the right partners, and form of alliances was studied. The research converged in understanding the fact that companies should move away from the transactional business model and have the right expectations and scoping on all sides, standardization, digital integration, and a steady focus on security and privacy

Effect of Stocking Rate on a \u3cem\u3eStipa Breviflora\u3c/em\u3e Desert Steppe Community of Inner Mongolia

Stocking rate is an important factor in grazing management. The stocking rate defines utilization and ultimately grazing pressure, which in turn affects grassland sustainability. Grassland sustainability is partly defined by its species composition and ultimately by its productivity. These attributes are unique for specific plant communities and the effect of stocking rate must be established for each in order to understand the community response to grazing and to determine its carrying capacity. While some information exists on the effects of stocking rate on livestock production in the Stipa breviflora Griseb. Desert Steppe (Wei et al., 2000), the effects on the plant community are not understood well. This study aimed to determine the effects of stocking rate on the species composition and productivity of that community

Impact of Global Climate Change on the European Barley Market Requires Novel Multi-Method Approaches to Preserve Crop Quality and Authenticity

Most recently in 2018 and 2019, large parts of Europe were affected by periods of massive drought. Resulting losses in cereal yield pose a major risk to the global supply of barley, as more than 60% of global production is based in Europe. Despite the arising price fluctuations on the cereal market, authenticity of the crop must be ensured, which includes correct declaration of harvest years. Here, we show a novel approach that allows such differentiation for spring barley samples, which takes advantage of the chemical changes caused by the extreme drought. Samples from 2018 were successfully differentiated from those of 2017 by analysis of changes in near-infrared spectra, enrichment in the isotope (13)C, and strong accumulation of the plant-physiological marker betaine. We demonstrate that through consideration of multiple modern analysis techniques, not only can fraudulent labelling be prevented, but indispensable knowledge on the drought tolerance of crops can be obtained

Технология проведения гидравлических испытаний промысловых нефтепроводов в условиях Западной Сибири

Объектом исследования является методика и технология проведения гидравлических испытаний нефтепровода. Целью данной работы является исследование актуальной научно-технической проблемы обеспечения требуемых условий и средств для проведения гидравлических испытаний промысловых нефтепроводов. В соответствии с поставленной целью были выдвинуты следующие задачи: 1. Определить необходимую номенклатуру и объем подготовительных работ для проведения испытаний промыслового нефтепровода; 2. Исследовать основные факторы и их влияние на процесс гидравлических испытаний нефтепровода в промысловых условиях; 3. Выбор средств и методов, исключающих влияние внешних факторов на достоверность результатов испытаний.The object of study is the methodology and technology for conducting hydraulic tests of the oil pipeline. The aim of this work is to study the urgent scientific and technical problems of providing the required conditions and means for conducting hydraulic tests of field pipelines. In accordance with the goal, the following tasks were put forward: 1. To determine the necessary nomenclature and scope of preparatory work for testing the oil field pipeline; 2. Investigate the main factors and their influence on the process of hydraulic testing of the pipeline in the field; 3. The choice of tools and methods that exclude the influence of external factors on the reliability of the test results

Acidic microenvironment plays a key role in human melanoma progression through a sustained exosome mediated transfer of clinically relevant metastatic molecules

Background: Microenvironment cues involved in melanoma progression are largely unknown. Melanoma is highly influenced in its aggressive phenotype by the changes it determinates in its microenvironment, such as pH decrease, in turn influencing cancer cell invasiveness, progression and tissue remodelling through an abundant secretion of exosomes, dictating cancer strategy to the whole host. A role of exosomes in driving melanoma progression under microenvironmental acidity was never described. Methods: We studied four differently staged human melanoma lines, reflecting melanoma progression, under microenvironmental acidic pHs pressure ranging between pH 6.0-6.7. To estimate exosome secretion as a function of tumor stage and environmental pH, we applied a technique to generate native fluorescent exosomes characterized by vesicles integrity, size, density, markers expression, and quantifiable by direct FACS analysis. Functional roles of exosomes were tested in migration and invasion tests. Then we performed a comparative proteomic analysis of acid versus control exosomes to elucidate a specific signature involved in melanoma progression. Results: We found that metastatic melanoma secretes a higher exosome amount than primary melanoma, and that acidic pH increases exosome secretion when melanoma is in an intermediate stage, i.e. metastatic non-invasive. We were thus able to show that acidic pH influences the intercellular cross-talk mediated by exosomes. In fact when exposed to exosomes produced in an acidic medium, pH naïve melanoma cells acquire migratory and invasive capacities likely due to transfer of metastatic exosomal proteins, favoring cell motility and angiogenesis. A Prognoscan-based meta-analysis study of proteins enriched in acidic exosomes, identified 11 genes (HRAS, GANAB, CFL2, HSP90B1, HSP90AB1, GSN, HSPA1L, NRAS, HSPA5, TIMP3, HYOU1), significantly correlating with poor prognosis, whose high expression was in part confirmed in bioptic samples of lymph node metastases. Conclusions: A crucial step of melanoma progression does occur at melanoma intermediate -stage, when extracellular acidic pH induces an abundant release and intra-tumoral uptake of exosomes. Such exosomes are endowed with pro-invasive molecules of clinical relevance, which may provide a signature of melanoma advancement

Применение информационных технологий и этические нюансы в управлении массовым сознанием

This paper discusses the current value of information technology in our lives, as well as their application to control the mass consciousness