Vygotsky’s natural history of signs

The paper organizes the topic of signs in Lev Vygotsky’s various writings into a coherent whole in order to study signs’ role in child development. Vygotsky related conventional signs that have their origin in interpersonal communication, and are subject to cultural history taking place over generations during historical time, to psychological functioning of individual human beings. Vygotsky’s “natural history of signs” is the study of how symbolic activity appears and develops. The paper outlines the process of inclusion of symbols within the behaviour of the child and gives an account of various changes in psychological functions and their interrelations that it brings along. In cultural development specifically human forms of behaviour appear, and children’s relationship to social and material environment is changed qualitatively. Vygotsky outlines the formation of sign use and analyses its developmental steps. Vygotsky’s approach explains how the use of various sign systems shapes both the cognitive processes in the person, the child, and the cognitive development as a whole. Vygotsky’s approach to signs is presented within the conceptual framework of its time

Differentiation of language functions during language acquisition based on Roman Jakobson’s communication model

The paper uses Roman Jakobson’s conceptual framework to study the development of communication of children. It sets out to explain how cardinal functions of verbal messages – referential, emotive, conative, phatic, metalingual and poetic – understood in terms of Jakobson’s communication model – progressively differentiate during children’s language acquisition. The differentiation of these functions is apparent in changes in children’s use of language, as it corresponds to the gradual formation and adoption of various linguistic structures in the development of speech. Children’s acquisition of the use of grammatical subject and predicate, corresponding to the appearance of specifically metalingual speech, among other linguistic structures, is related to children’s adaptation to the linguistic environment. The article relates differentiation of metalingual and poetic functions to the development of children’s thinking using the example of crib talk

The Heart-Placenta Axis in the First Month of Pregnancy: Induction and Prevention of Cardiovascular Birth Defects

Extrapolating from animal studies to human pregnancy, our studies showed that folate (FA) deficiency as well as one-time exposure to environmental factors in the first two to three weeks of human gestation can result in severe congenital heart defects (CHDs). Considering that approximately 49% of pregnancies are unplanned, this period of pregnancy can be considered high-risk for cardiac, as well as for neural, birth defects, as the woman usually is not aware of her pregnancy and may not yet be taking precautionary actions to protect the developing embryo. Using avian and mouse vertebrate models, we demonstrated that FA supplementation prevents CHD induced by alcohol, lithium, or elevation of the metabolite homocysteine, a marker for FA deficiency. All three factors affected the important Wnt signaling pathway by suppressing Wnt-mediated gene expression in the heart fields, resulting in a delay of cardiomyocyte migration, cardiomyogenesis, and CHD. Optimal protection of cardiogenesis was observed to occur with FA supplementation provided upon morning after conception and at higher doses than the presently available in prenatal vitamin supplementation. Our studies demonstrate pathways and cell processes that are involved with protection of one-carbon metabolism during heart development

Südame areng ja kaasasündinud rikked. Biomehaaniline perspektiiv

Südamerikked ilmnevad umbes 1%-l elusalt sündinud lastest. Uuringud on näidanud, et kõigist kaasasündinud riketest esinevad kõige sagedamini südamerikked. Viimase aja uuringud on esile toonud mitmeid põhjusi, mis soodustavad kaasasündinud südamerikete kujunemist. Ühelt poolt võib sellel olla molekulaarbioloogiline põhjus – geenimutatsioon –, mis on tingitud nukleotiidide muutustest geenides (1). Teiselt poolt on mõjuteguriks emakasisene keskkond, mida võib mõjutada ema eluviis ja käitumine, näiteks alkoholitarbimine, suitsetamine, narkootikumide, ravimite tarvitamine (2, 3). Samuti võib embrüo areng olla häiritud mõningate toitainete puudusest emal, näiteks foolhappe puudus ja sellest tulenev homotsüsteiinisisalduse suurenemine veres (4). Kirjeldatud tegurid võivad mõjutada loote arengut väga varajases perioodis, kui ema veel ei teagi, et ta on rase. Harilikult tuvastab naine raseduse 5.–6. nädalal pärast viljastumist. Tuksuv süda ja vereringe kujuneb lootel juba 3. viljastumisjärgsel nädalal (16.–21. päeval). Seega võivad südame arengut mõjutavad tegurid toimida juba siis, kui naine ei olegi oma rasedusest teadlik. Südamerikete kujunemise põhjuste selgitamiseks on vaja uurida loote arengu väga varajasi perioode. Eesti Arst 2013; 92(2):80–8

Learning Effects of the Flipped Classroom in a Principles of Microeconomics Course Running Header: Flipped Principles of Micro

The authors of this article estimate the learning effects of the flipped classroom format using data from 16 sections of principles of microeconomics over a 4-year period. The experimental design is unique in that two treatment and two control sections were taught during the fall semester in four consecutive years. Further, the instructor switched the time of day when the treatment and control sections were taught each year. Controlling for gender, ACT score, a normed high school GPA, Pell Grant award, time of day, and initial knowledge of economics, the authors find no evidence of increased learning using end-of-semester measures for students in the flipped classroom in comparison to sections with a moderate amount of active learning

Introduction: Framing nature and culture

Introduction: Framing nature and culture

Measuring Faculty Teaching Effectiveness Using Conditional Fixed Effects

Using a dataset of 48 faculty members and 88 courses over 26 semesters, the authors estimate Student Evaluation of Teaching (SET) ratings that are conditional on a multitude of course, faculty, and student attributes. They find that ratings are lower for required courses and those where students report a lower prior level of interest. Controlling for these variables substantially alters the SET ratings for many instructors. The average absolute value of the difference between the faculty ratings controlling just for time effects and fully conditional ratings is nearly one-half of a standard deviation in the students’ rating of how much they learned. This difference produces a change in quartile rank for over half the sample across two summary course evaluation measures

Could tariffs be pro-cyclical?

Conventional wisdom says that tariffs are counter-cyclical. We analyze the relationship between business cycles and applied MFN tariffs using a disaggregated product-level panel dataset covering 72 countries between 2000 and 2011. Strikingly, and counter to conventional wisdom, we find that tariffs are pro-cyclical. Further investigation reveals that this pro-cyclicality is driven by the tariff setting behavior of developing countries; tariffs are acyclical in developed countries. We present evidence that pro-cyclical market power drives the pro-cyclicality of tariffs in developing countries, providing further evidence of the importance of terms of trade motivations in explaining trade policy

Costly distribution and the non-equivalence of tariffs and quotas

When governments impose a quota or tariff on imports, it is well known that the resulting rents and revenues trigger costly rent-seeking and revenue-seeking activities, which are welfare-reducing and may be economically more significant than the efficiency losses resulting from the protectionist-induced resource misallocation. Repeated interaction among firms can eliminate wasteful rent- and revenue-seeking expenditures through cooperation. We show that while aggregate outcomes are equivalent under tariffs and quotas if cooperation arises, the conditions under which cooperation arises differ by policy. This difference arises because a firm must incur additional cost to physically import and distribute the goods associated with additional quota licenses, whereas there is no such cost when it comes to consuming additional tariff revenue. Thus, quotas and tariffs are non-equivalent. We provide a simple sufficient condition under which cooperative elimination of rent-seeking under quotas is easier than cooperative elimination of revenue-seeking under tariffs and therefore a quota is the preferred policy whenever the policy admits cooperation