Hashmoney: Exploring Twitter Hashtag Use as a Secondary Ticket Market Price Determinant

The growth and prevalence of sport event ticket transactions on secondary ticket market platforms such as StubHub has led to the creation of a body of academic research studying this new phenomenon. Factors such as team performance and perceptions of fairness have been explored for their relationship with the price of secondary market tickets. This exploratory study introduces a new potential price determinant – social media activity – itself a popular online phenomenon that has inspired considerable academic research. This exploratory study of prices for eight National Football League games adds use of official team hashtags on Twitter to a multiple regression model, controlling for other price determinants established in previous research two models, one to predict prices for tickets sold on StubHub, the second to predict prices for tickets available on StubHub, demonstrate that increased Twitter hashtag use is a significant positive predictor of ticket prices on the secondary marke

The role of the magnetosonic Mach number on the evolution of Kelvin-Helmholtz vortices

We review the main results of our previous works, in which we have investigated the development of the Kelvin-Helmholtz (KH) instability in the transitional regime from sub magnetosonic to super-magnetosonic by varying the solar wind velocity, in conditions typical of those observed at the Earth's magnetopause flanks. In super-magnetosonic regimes, we show that the vortices produced by the development of the KH instability act as an obstacle in the plasma flow and may generate quasi-perpendicular magnetosonic shock structures extending well outside the region of velocity shear

Nonlinear evolution of the magnetized Kelvin-Helmholtz instability: from fluid to kinetic modeling

The nonlinear evolution of collisionless plasmas is typically a multi-scale process where the energy is injected at large, fluid scales and dissipated at small, kinetic scales. Accurately modelling the global evolution requires to take into account the main micro-scale physical processes of interest. This is why comparison of different plasma models is today an imperative task aiming at understanding cross-scale processes in plasmas. We report here the first comparative study of the evolution of a magnetized shear flow, through a variety of different plasma models by using magnetohydrodynamic, Hall-MHD, two-fluid, hybrid kinetic and full kinetic codes. Kinetic relaxation effects are discussed to emphasize the need for kinetic equilibriums to study the dynamics of collisionless plasmas in non trivial configurations. Discrepancies between models are studied both in the linear and in the nonlinear regime of the magnetized Kelvin-Helmholtz instability, to highlight the effects of small scale processes on the nonlinear evolution of collisionless plasmas. We illustrate how the evolution of a magnetized shear flow depends on the relative orientation of the fluid vorticity with respect to the magnetic field direction during the linear evolution when kinetic effects are taken into account. Even if we found that small scale processes differ between the different models, we show that the feedback from small, kinetic scales to large, fluid scales is negligable in the nonlinear regime. This study show that the kinetic modeling validates the use of a fluid approach at large scales, which encourages the development and use of fluid codes to study the nonlinear evolution of magnetized fluid flows, even in the colisionless regime

Degradación del Pesticida Clorpirifós por Bacterias Ácido-Lácticas

Los pesticidas organofosforados (OPPs) son uno de los grupos de pesticidas químicos empleados actualmente en agricultura y que contribuyen en más del 36% al total del mercado mundial. El clorpirifós (CF) es el pesticida organofosforado más utilizado en Argentina. Los OPPs son compuestos neurotóxicos y la contaminación de la tierra, aguas superficiales y alimentos representa un potencial riesgo para la salud. Se ha demostrado que las Bacterias Acido Lácticas (BAL) son capaces de degradarlos a partir de mecanismos seguros y métodos económicos. El objetivo del presente estudio fue investigar la biodegradación del CF por BAL. Leuconostoc mesenteroides fue aislada a partir de muestras de origen frutihortícolas, utilizando MRS (De Man, Rogosa y Sharpe) como medio de aislamiento. La cepa fue identificada a partir de su taxonomía por microscopia óptica y mediante las pruebas API CH-50 (Biomériux). La cepa Lactobacillus fermentum (ATCC 9338) fue adquirida de Medica-Tec S.R.L. La degradación del CF se estudió incubando cada BAL en caldo MRS (24 h, 35°) en presencia del pesticida (1,2 mg L-1) monitoreando su concentración a 0, 6, 12 y 24 h. Simultáneamente se realizaron controles de crecimiento por el método de recuento en placa empleando agar MRS. La extracción y purificación del OPP se realizó por cromatografía en columna utilizando sílica-gel y sulfato de sodio como fase estacionaria y hexano como eluyente. La cuantificación del CF se efectuó a través de cromatografía gaseosa (Shimadzu CGMSQP2010 ULTRA-AOC20I) con detección por espectrometría de masas. Los resultados de los ensayos de contacto de ambas cepas manifestaron un impacto positivo en la degradación del CF evidenciado por sus constantes de degradación. La degradación de los OPPs por BAL sigue una cinética de pseudo primer orden. Las cepas L. mesenteroides y L.fermemtum, mostraron una taza de degradación del 97% y 57%, respectivamente, en tanto sus constantes cinéticas fueron 0,1318 h-1 y 0,0178 h-1 . En cuanto a la evolución de la población bacteriana durante el período del ensayo, el recuento de L. mesenteroides se incrementó durante las primeras 6 h (de 105 a 108 UFC mL-1) y luego permaneció aproximadamente constante. El recuento de L. fermentum se mantuvo constante (105 UFC mL-1) al comienzo y se incrementó en 3 órdenes de magnitud, durante las últimas 18 h del estudio. Paralelamente se llevó a cabo un ensayo control, sin BAL, que no mostró variaciones en la concentración del CF. Según los resultados obtenidos, Leuconostoc mesenteroides resultó más eficiente para la biodegradación de CF, asegurando una disminución de la concentración de 97 %.Fil: Pardini, Agustina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Química; ArgentinaFil: Pegoraro, César Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Biológicas. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Biológicas; ArgentinaFil: Iurlina, Miriam O.. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Química; ArgentinaFil: Saiz, Amelia I.. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Química; ArgentinaXXI Congreso Latinoamericano y del Caribe de Ciencia y Tecnología de Alimentos. XVII Congreso Argentino de Ciencia y Tecnología de AlimentosBuenos AiresArgentinaAsociación Argentina de Tecnólogos Alimentario

HERG potassium channels are constitutively expressed in primary human acute myeloid leukemias and regulate cell proliferation of normal and leukemic hemopoietic progenitors

An important target in the understanding of the pathogenesis of acute myeloid leukemias (AML) relies on deciphering the molecular features of normal and leukemic hemopoietic progenitors. In particular, the analysis of the mechanisms involved in the regulation of cell proliferation is decisive for the establishment of new targeted therapies. To gain further insight into this topic we report herein a novel approach by analyzing the role of HERG K+ channels in the regulation of hemopoietic cell proliferation. These channels, encoded by the human ether-a-go-go-related gene (herg), belong to a family of K, channels, whose role in oncogenesis has been recently demonstrated. We report here that herg is switched off in normal peripheral blood mononuclear cells (PBMNC) as well as in circulating CD34(+) cells, however, it is rapidly turned on in the latter upon induction of the mitotic cycle. Moreover, herg appears to be constitutively activated in leukemic cell lines as well as in the majority of circulating blasts from primary AML. Evidence is also provided that HERG channel activity regulates cell proliferation in stimulated CD34(+) as well as in blast cells from AML patients. These results open new perspectives on the pathogenetic role of HERG K+ channels in leukemias

Seed germination and seedling growth of canola treated with abiotic factors that can affect growth and development.

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Avaliação da soro prevalência de leptospirose em rebanhos leiteiros da região sul do Rio Grande do Sul.

O objetivo deste estudo foi avaliar a soro prevalência da leptospirose bovina e identificar os sorovares prevalentes em diferentes rebanhos da região Sul do Rio Grande Sul