RICH POINTS IN BETWEEN CULTURES, LANGUAGES, AND PEDAGOGIES: EXPERIENCES AND PERSPECTIVES OF INTERNATIONAL TEACHING ASSISTANTS IN THE USA

ABSTRACT This study presents a qualitative, multiple case, instrumental case study which explores experiences and positionality of International Teaching Assistants (ITAs) in the US academia. Drawing from, first, the earlier research which focuses on ITAs’ language, culture, and pedagogy with, mostly, a “deficit” perspective and, second, from recent publications which concentrate on exploring ITAs’ identities and perceptions, this study investigates how ITAs approach differences and similarities (rich points) during everyday discourses in their various communities of practice. The conceptual framework is represented by Agar’s (1996, 2006) vision on rich points (differences and similarities); Lave and Wenger’s (1991) concept of community of practice (CoP), and the notion of narratives (Clandinin & Connelly, 1994; Simons, 2009). The theoretical framework is informed by Vygotsky’s sociocultural theory, specifically, by the concept of perezhivanie (lived through emotional experience). Two cases of ITA communities which are bound to certain university settings (in the Northwest and Southwest of the US) were analyzed. Purposive (snowball) sampling was used to find focal participants. Eight ITAs took part in a semester-long data collection. The study utilized an electronic survey; one informal conversational interview; one semi-structured interview; one to two observations with debriefings; and collection of artifacts and visual data. The findings revealed that there are five major ways for ITAs to mediate rich points, namely, via ITAs’ multiple identities, ITAs’ self-analysis, ITAs’ internalization of politics and policies, ITAs’ internalization of others’ actions in the US academia and, ITAs’ teaching evolution. Rich points are observed as a vital aspect of ITAs’ development. At the same time, mediation of rich points is always unique and dynamic and presupposes a combination of several navigational techniques. The significance of the study is predetermined by the necessary contribution into the recent research on ITAs’ identities as the opposition to the previously projected “deficit theory” in respect to ITAs. Also, the study explored ITAs’ various communities of practice while the recent research tends to focus on ITAs’ classroom as their only major environment. It is suggested that ITAs’ experiences should be researched further, especially, for providing more meaningful practices for ITAs’ socialization in the US academia

Desalination using polyelectrolyte hydrogels

When the gel is put into contact with aqueous salt solution, it absorbs a solution with the ion composition different from the original one. The absorbed solution can be easily squeezed out from the gel by means of sieve or microfiltration membrane. In our previous work we proposed a fully reversible desalination cycle made of compression and swelling steps, which can in principle work on ideal thermodynamic efficiency. In this work we simulate the desalination process using theoretical and coarse-grained models of gel and prove the concept by experiment. We used Monte Carlo and molecular dynamics molecular simulations in the reaction ensemble to predict the degree of ionization of the weak polyelectrolyte hydrogel when it is put in contact with salt solution, and calculate the salt partitioning between the gel and bulk salt solution. We constructed laboratory apparatus based on swelling and pressing cycles of the gel. First, we let the polyelectrolyte gel swell with salt solution of defined concentration. Then we press the gel and the liquid is released. Due to the ion exchange in polyelectrolyte hydrogel, this released liquid has lower salt concentration than the initial one. We measure the salinity of the solution before and after this procedure and we compare the results with theoretically obtained salt partitioning. We also measure the pressure applied on the gel and corresponding gel volume and compare these results with respective computational results

High power gain for stimulated Raman amplification in CuAlS2

Cataloged from PDF version of article.The spontaneous Raman spectra of the chalcopyrite structure crystal CuAlS2, which is promising for nonlinear optical applications, has been investigated at 8 and 300 K. The main aim of this study is to compare the absolute spontaneous Raman scattering efficiency in CuAlS2 crystals with that of their isomorphous analog, zinc-blende structure GaP crystals, known as one of the most efficient materials for amplification. Observation of a high value of absolute scattering efficiency S/L d Omega (where S is the fraction of incident power that scatters into the solid angle d Omega and L is the optical path length with S/L d Omega=9.5X10(-5) cm(-1) sr(-1)), together with relatively narrow linewidth (Gamma=5.1 cm(-1), full width at half maximum at room temperature and Gamma=1.5 cm(-1) at 8 K for the strongest Gamma(1) phonon mode of CuAlS2 at 314 cm(-1)) indicate that CuAlS2 has the highest value of the stimulated Raman gain coefficient g(s)/I where I is the incident laser power density, The calculated value of this gain is g(s)/I=2.1X10(-6) cm(-1)/W at 300 K and 50X10(-6) cm/W, at 8 K for 514.5 nm laser excitation, and is larger than those for the appropriate vibrational modes of various materials (including GaP, LiNbO3, Ba2NbO5O15, CS2 and H-2) investigated so far. The calculations show that cw Raman oscillator operation in CuAlS2 is feasible with low power threshold of pump laser. (C) 1996 American Institute of Physics

Cadmium-free Thin-Film Cu(In,Ga)Se2(In2S3) Heterophotoelements Fabrication and Properties

The method of heat treatment of metallic Cu–In–Ga layers in the N2 inert atmosphere in the presence of selenium and sulfur vapors was used to grow homogeneous films of Cu(In,Ga)(S,Se)2 alloys onto which the CdS or In2S3 films were deposited and, on the basis of these structures, the thin-film glass/Mo/p-Cu(In,Ga)(S,Se)2/n-(In2S3,CdS)/n-ZnO/Ni–Al photoelements were fabricated. The mechanisms of charge transport and the processes of photosensitivity in the obtained structures subjected to irradiation with natural and linearly polarized light are discussed. The broadband hotosensitivity of thin-film heterophotoelements and the induced photopleochroism were detected; these findings indicate that there is an interference-related blooming of the structures obtained. It is concluded that it is possible to use ecologically safe cadmium-free thin-film heterostructures as high-efficiency photoconverters of solar radiation

Quality indicators of fish from the water of the southern region of Ukraine

A study of the fish caught in the reservoirs of the Khadzhibey estuary (Odesa region) was conducted in order to determine its quality and safety according to microbiological indicators. No pathogenic or conditionally pathogenic microorganisms were found in all the fish samples studied – mirror carp (Cyprinus carpio) and round goby (Neogobius melanostomus). During the study of physico-chemical indicators of water quality and safety of the estuary, water samples were taken for the content of pesticides, insecticides and heavy metals. The content of cadmium, copper, lead and mercury does not exceed the permissible level for fish farms, zinc exceeds the maximum permissible concentration by 2.3 – 3.0 % (depending on the period of the year). The insecticide dichlorodiphenyltrichloromethylmethane was found in the water, the content of which exceeds the maximum allowable concentration for sea fishing ponds by 18 %, and the pesticide beta-hexochlorocyclohexane – by 5.2 %. It has been studied and established that the fish caught in the estuary, according to its microbiological and physicochemical indicators, is safe, does not pose a threat to the health of people and animals, and is suitable for further use and consumption

Дія стрес-факторів на показники неспецифічної резистентності і продуктивність поросят

Feeding «feed mixture STO HA» piglets had a positive impact on their resistance and performance in the early postnatal period and the first week after weaning. Research has established that the content of total protein in pigs 4 day age 2nd and 3rd groups did not significantly different from the control group, while their peers from the 4th group born from sows that received «feed mixture STO HA» specified an indicator was higher by 2.8%. The level of total protein in piglet 2 nd, 3 rd, 4 th groups of 16-day age was higher by 5.8, 6.2, 8.8% (P < 0.05), respectively, in the control group, the 40th day age – significantly (P < 0.05) higher than same indicator 9.9, 8.6, 9.6% respectively. The difference in levels of immunoglobulin A in pigs receiving «feed mixture STO HA» (2nd and 4th groups) in 16 aged and performance of piglets 1st (control) group was 54.5 – 81.8% and was statistically significant (P < 0.05 – P < 0.01). The 28-day age and concentration of Ig A serum pigs 2nd and 4th groups significantly exceeded by 72.2 and 77.7% rate in the control group, the 40th day age at 60.6 and 54,5%, respectively (P < 0.05). The bactericidal activity of blood serum piglets 40 days old all research groups significantly (P < 0.05 – P < 0.01) greater than 15.9, 11.3, 14.8% performance of their peers in the control group. Lysozyme activity of blood serum pigs 2nd, 3rd, 4th groups and 28 days old dominated his peers likely group 1 15.3, 11.7, 15.6% in the 40-day age – to 19.0; 16.7; 19.8% respectively. Phagocytic activity of leukocytes in pigs 4 days old 4th group born from sows that received «feed mixture STO HA» was higher by 5.7, 9.5, 10.4% compared to piglets 1 – 3rd groups. Phagocytic activity of leukocytes pigs 2nd, 3rd, 4th groups 16 days old and has been above 18.3 (P < 0.05); 11.5; 16.8% (P < 0.05), respectively group 1, the 28-day age – 17.4 (P < 0.05); 12.9 (P < 0.05); 15.2%. Phagocytic activity of leukocytes in piglets 40th age of daily study groups was significantly (P < 0.05) higher respectively pigs in the control group. The difference between the performance of piglets second and the first group was 20.5%, the first and third – 16.0%, fourth and first – 18.6%. The intensity of phagocytosis (FI) in pigs 16-day age 2 nd, 3 rd, 4 th group was significantly higher at 16.5 (P <0.05), 12.9, 22.4% (P < 0.01), the 40th day age – to 23.6, 20.1, 21.3%, respectively (P < 0.05, P < 0.01) compared with the control group. The average daily gain  of the piglets 4th group of from 31 th to 40 th day of life superior piglets of group 1 to 58.3%, and body weight in 40-day age – 15.5% (P < 0.01). Згодовування «Суміші кормової Сто Га» поросятам сприятливо впливає на показники їх резистентності та продуктивність в ранній постнатальний період і в перший тиждень після відлучення. Бактерицидна активність сироватки крові поросят 40-добового віку всіх дослідних груп  вірогідно (Р <0,05 – Р < 0,01) перевищувала на 15,9, 11,3, 14,8% показники їх однолітків з контрольної групи. Лізоцимна активність сироватки крові поросят 2-ї, 3-ї, 4-ї груп 28-добового віку вірогідно переважали своїх однолітків 1-ї групи на 15,3, 11,7, 15,6%, у 40-добовому віці – на 19,0, 16,7, 19,8% відповідно. Інтенсивність фагоцитозу (ФІ) у поросят 16-добового віку 2-ї, 3-ї, 4-ї груп була вірогідно вищою на 16,5 (Р < 0,05), 12,9, 22,4% (Р < 0,01), у 40-добового віці – на 23,6, 20,1, 21,3% відповідно (Р < 0,05; Р < 0,01) порівняно з контрольною групою.  За середньодобовим приростом поросята 4-ї групи в період з 31-го до 40-го дня життя перевершували поросят 1-ї групи на 58,3%, а за живою масою в 40-добовому віці – на 15,5% (Р < 0,01)

Influence of technology of synthesis on structure and properties of the sintered composit of system Ti-Fe-C

Досліджено фізико-механічні характеристики матеріалу отриманого методом пічного спікання та методом СВС. Порівняльний аналіз фізико-механічних властивостей матеріалу з однаковим хімічним складом отриманий методом пічного спікання та методом СВС-процесу свідчить, що пористість зразків не залежить від методу спікання. Показано, що на деформаційні характеристики та твердість матеріалу метод спікання не впливає. Встановлено, що для зразків з однаковим хімічним складом та пористістю механічні параметри при СВС спіканні зростають у 1,5 рази порівняно з пічним спіканням за рахунок зміцнення зв'язків між елементами системи. Для зразків отриманих методом СВС при дослідженні структури руйнування спостерігається крихке руйнування, при пічному методі внаслідок статичного стиснення у зразку з'являються глибокі тріщини, що приводять до його руйнування. Таким чином, доведено, що для отримання матеріалів конструкційного призначення доцільно використовувати відходи машинобудівного виробництва зменшивши енерговитрати за рахунок СВС-процесів.Purpose. Comparisons of the traditional stove method of sintered and SHS-process and their influence on physic-mechanical properties of composition material, got on the basis of charge from powders of titan, steel of BBS15 and carbon. Design/methodology/approach.. By authors properties of material were considered on the basis of Ti-Fe, that got the traditional stove method of sintered, which is an charges of energy. In this case we suggest to use a SHS-method which with less expenses and more simple equipment allows to get materials with the best physics-mechanical by properties. Findings. More strong descriptions of material got by the method of SHS in 1,5 times higher, than for standards got by the of stove method. Originality/value. It is expedient to use wastes of machine-building production due to SHS-process for the receipt of construction materials.Исследовано физико-механические характеристики материала полученного методом печного спекания и методом СВС. Сравнительный анализ физико-механических свойств материала с одинаковым химическим составом полученный методом печного спекания и методом СВС-процесса свидетельствует, что пористость образцов не зависит от метода спекания. Показано, что на деформационные характеристики и на твердость материала метод спекания не влияет. Установлено, что для образцов с одинаковым химическим составом и пористостью механические параметры при СВС спекании растут в 1,5 разы в сравнении с печным спеканием за счет укрепления контактов между элементами системы. Для образцов полученных методом СВС при исследовании структуры разрушения наблюдается хрупкое разрушение, при печном методе в результате статического сжатия в образце появляются глубокие трещины, которые приводят к его разрушению. Таким образом, доказано, что для получения материалов конструкционного назначения целесообразно использовать отходы машиностроительного производства, уменьшив энергозатраты за счет СВС-процессов