Steric Effects of Alkyl Ammonium Salts on the Combustion of Exchanged Smectite Clays

Bomb calorimetry was explored as a new method for determining the cation exchange capacity (CEC) of clays. Smectite clays were modified with several alkyl ammonium salts varying in number of carbons and the spatial orientation of the carbons about the central nitrogen atom. The clays used, standards purchased from the Source Clay Repository, have CECs of 44, 80, 88, and 120 meq/100 g. Theoretically, the combustion energy of the organo-clays should be approximately the same for each salt. Any differences in energy would be due to the different structures of the salts and how they are oriented in the interlamellar region of the clay. The number of alkyl ammonium salts that bind to the negatively charged sites in the clay layers would represent the CEC of the clay. The orientation of the organic cation in the interlamellar region was examined using x-ray powder diffraction, which provides the spacing between the clay layers. The combustion energy data collected using bomb calorimetry was used to calculate the CEC of the clay by comparing the energy from the pure salts to determine the number of salt molecules intercalated into the clay. Since the pure salt and the clay have a one-to-one charge ratio, the number of salt molecules will directly represent the number of negatively charged sites on the clay which is the CEC of the clay

Ca II triplet spectroscopy of small magellanic cloud red giants. II. abundances for a sample of field stars

We have obtained metallicities of ∼360 red giant stars distributed in 15 Small Magellanic Cloud (SMC) fields from near-infrared spectra covering the Ca II triplet lines using the VLT + FORS2. The errors of the derived [Fe/H] values range from 0.09 to 0.35 dex per star, with a mean of 0.17 dex. The metallicity distribution (MD) of the whole sample shows a mean value of [Fe/H] = -1.00 ± 0.02, with a dispersion of 0.32 0.01, in agreement with global mean [Fe/H] values found in previous studies. We find no evidence of a metallicity gradient in the SMC. In fact, on analyzing the MD of each field, we derived mean values of [Fe/H] = -0.99 ± 0.08 and [Fe/H] = -1.02 ± 0.07 for fields located closer and farther than 4° from the center of the galaxy, respectively. In addition, there is a clear tendency for the field stars to be more metal-poor than the corresponding cluster they surround, independent of their positions in the galaxy and of the clusters' age. We argue that this most likely stems from the field stars being somewhat older and therefore somewhat more metal-poor than most of our clusters. © 2010. The American Astronomical Society.Fil: Parisi, Maria Celeste. Universidad Nacional de Cordoba. Observatorio Astronomico de Cordoba; ArgentinaFil: Geisler, Doug. Universidad de Concepción; ChileFil: Grocholski, A. J.. University of Florida; Estados Unidos. Space Telescope Science Institute; Estados UnidosFil: Claria Olmedo, Juan Jose. Universidad Nacional de Cordoba. Observatorio Astronomico de Cordoba; ArgentinaFil: Sarajedini, A.. University of Florida; Estados Unido

Ancestry-Dependent Enrichment of Deleterious Homozygotes in Runs of Homozygosity.

Runs of homozygosity (ROH) are important genomic features that manifest when an individual inherits two haplotypes that are identical by descent. Their length distributions are informative about population history, and their genomic locations are useful for mapping recessive loci contributing to both Mendelian and complex disease risk. We have previously shown that ROH, and especially long ROH that are likely the result of recent parental relatedness, are enriched for homozygous deleterious coding variation in a worldwide sample of outbred individuals. However, the distribution of ROH in admixed populations and their relationship to deleterious homozygous genotypes is understudied. Here we analyze whole-genome sequencing data from 1,441 unrelated individuals from self-identified African American, Puerto Rican, and Mexican American populations. These populations are three-way admixed between European, African, and Native American ancestries and provide an opportunity to study the distribution of deleterious alleles partitioned by local ancestry and ROH. We re-capitulate previous findings that long ROH are enriched for deleterious variation genome-wide. We then partition by local ancestry and show that deleterious homozygotes arise at a higher rate when ROH overlap African ancestry segments than when they overlap European or Native American ancestry segments of the genome. These results suggest that, while ROH on any haplotype background are associated with an inflation of deleterious homozygous variation, African haplotype backgrounds may play a particularly important role in the genetic architecture of complex diseases for admixed individuals, highlighting the need for further study of these populations

EL IMPACTO REGIONAL DE LOS PROGRAMAS DE FINANCIAMIENTO EN LAS UNIVERSIDADES ARGENTINAS

A partir de las reformas implementadas en el sector universitario en los años 90 las autoridades nacionales en Argentina distribuyen los recursos estatales entre las universidades nacionales bajo una modalidad combinada entre el presupuesto histórico, cuyo destino es el financiamiento de las actividades en general, y los mecanismos de asignación por programas para objetivos específicos, que buscan atender objetivos de desarrollo y mejoramiento académico de las instituciones. Estas medidas implementadas buscan promover el uso eficiente de los recursos, y su distribución ha considerado el desempeño de las instituciones frente a indicadores de eficiencia y equidad, tales como egresados/inscriptos, auxiliares profesores y materias aprobadas por alumnos (Decibe, 1999). Entre los factores relativos a la asignación de recursos que atañe más directamente a la utilización del subsidio a la educación superior en la Argentina interesa aquellos relacionados con la distribución regional. En esta oportunidad, nuestro objetivo está centrado en analizar si la asignación de los programas de financiamiento entre las universidades está relacionada con la distribución geográfica de las universidades. El diseño metodológico contempla el uso de la herramienta estadística de análisis discriminante, que establece una regla de decisión para la clasificación en grupos de las universidades. El estudio de carácter exploratorio considera diversos indicadores de desempeño económico y académico de las instituciones para el año 2008 y la distribución geográfica de las universidades atendiendo a su ubicación en su respectivo CPRES (Consejos de Planificación Regional de la Educación Superior)

Análisis de prefactibilidad de un proyecto de turismo rural en la ciudad de Balcarce, provincia de Buenos Aires, Argentina

El turismo constituye una actividad económica dinamizadora, y dentro del mismo, el turismo rural representa para el sector agropecuario y para las comunidades locales una oportunidad para la generación de empleo directo e indirecto; una alternativa para diversificar y ampliar los ingresos, y una forma de difundir y revalorizar las culturas, tradiciones, prácticas y saberes locales. De esta manera, el presente trabajo se propone analizar la prefactibilidad de un proyecto de inversión para brindar un servicio de turismo rural en un terreno propio en el Partido de Balcarce. Para ello se realizó una caracterización del predio, se llevo a cabo un análisis Fortalezas-Oportunidades-Debilidades-Amenazas (FODA); se estimó el monto de la inversión inicial, los ingresos y los costos de prestación del servicio; se elaboró un flujo de fondos para estimar el Valor Actual Neto (VAN) y, finalmente, un análisis de sensibilidad con 9 escenarios posibles, donde se obtuvieron resultados negativos y positivos que oscilaron entre -1,38 y 1,74 millones de pesos.Tourism is a dynamic economic activity, and rural tourism represents for the agriculture sector and for the local communities an opportunity to create direct and indirect employment, and an alternative strategy to spread out incomes. It is also a way to increase de value of cultures, traditions, practices and local knowledges. Therefore, the aim of this report is to analyze the feasibility of a Project Investment to offer services in rural tourism in an own field in Balcarce. To this end, it was conducted a characterization and analysis of the fiel's natural resources, and it was further elaborated a DAFO analysis. In adittion, it was estimated the amount of the initial investment, as well as the cost of providing the service and the estimated incomes. Morever, it was developed a model to estimate the project's cash flow and the Net Present Value (NPV). Finally, it was made a sensitivity analysis in respect of nine scenarios, in which were obtained negative and positive scores ranging from -1.38 through to 1.74 million pesos.Fil: Rodríguez, Julieta A. Universidad Nacional de Mar del Plata. Facultad de Ciencias Económicas y Sociales; Argentina.Fil: Mujica, Guillermina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Molpeceres, Celeste. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina

Mode Identification from Combination Frequency Amplitudes in ZZ Ceti Stars

The lightcurves of variable DA stars are usually multi-periodic and non-sinusoidal, so that their Fourier transforms show peaks at eigenfrequencies of the pulsation modes and at sums and differences of these frequencies. These combination frequencies provide extra information about the pulsations, both physical and geometrical, that is lost unless they are analyzed. Several theories provide a context for this analysis by predicting combination frequency amplitudes. In these theories, the combination frequencies arise from nonlinear mixing of oscillation modes in the outer layers of the white dwarf, so their analysis cannot yield direct information on the global structure of the star as eigenmodes provide. However, their sensitivity to mode geometry does make them a useful tool for identifying the spherical degree of the modes that mix to produce them. In this paper, we analyze data from eight hot, low-amplitude DAV white dwarfs and measure the amplitudes of combination frequencies present. By comparing these amplitudes to the predictions of the theory of Goldreich & Wu, we have verified that the theory is crudely consistent with the measurements. We have also investigated to what extent the combination frequencies can be used to measure the spherical degree (ell) of the modes that produce them. We find that modes with ell > 2 are easily identifiable as high ell based on their combination frequencies alone. Distinguishing between ell=1 and 2 is also possible using harmonics. These results will be useful for conducting seismological analysis of large ensembles of ZZ Ceti stars, such as those being discovered using the Sloan Digital Sky Survey. Because this method relies only on photometry at optical wavelengths, it can be applied to faint stars using 4 m class telescopes.Comment: 73 pages, 22 figures, accepted in the Ap

Morphometric differences in the grasshopper Cornops aquaticum (Bruner, 1906) from South America and South Africa

The semi-aquatic grasshopper Cornops aquaticum is native to South America and inhabits lowlands from southern Mexico to Central Argentina and Uruguay. It is host-specific to aquatic plants in the genera Eichhornia and Pontederia. A quarantine population has existed in South Africa for 10 y, and it is planned to release it there as a biological control agent of water hyacinth, E. crassipes. Various studies of C. aquaticum are coordinated under HICWA (www.mpil-ploen.mpg.de). This paper compares the morphometry of the release population and 11 native populations in South America. We tested four hypotheses: 1) South African and South American populations of C. aquaticum differ in morphology; 2) the South African laboratory population is more similar to other isolated populations in South America than to nonisolated populations; 3) morphology differs across sites; 4) morphology differs with host plant. South African populations differed from continental nonisolated populations, but not from continental isolated ones. Isolated populations presented smaller individuals than nonisolated, but there was also a change in male morphology: while in nonisolated populations male wing length was similar to their body length, in isolated populations, male wings were smaller than body length. Females were larger when on Eicchornia azurea than on E. crassipes, while males presented larger wings than their body on E. azurea, and similar lengths on E. crassipes. These morphological changes may have resulted from phenotypic plasticity, selection for small size, or because of a loss of genetic diversity in quantitative traits.Fil: Adis, Joachim. Institute for Limnology; AlemaniaFil: Sperber, Carlos F. Universidade Federal de Viçosa; BrasilFil: Brede, Edward G. Institute for Limnology; AlemaniaFil: Capello, Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Franceschini, Maria Celeste. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Hill, Martin. Rhodes University; SudáfricaFil: Lhano, Marcos G. Universidade Federal de Viçosa; BrasilFil: Marques, Marinê. A;z M.. Universidade Federal de Mato Grosso; BrasilFil: Nunes, Ana L.. Muséu Paraense Emílio Goeldi; BrasilFil: Polar, Perry. CAB International; Trinidad y Tobag

A comprehensive resource for induced pluripotent stem cells from patients with primary tauopathies

Primary tauopathies are characterized neuropathologically by inclusions containing abnormal forms of the microtubule-associated protein tau (MAPT) and clinically by diverse neuropsychiatric, cognitive, and motor impairments. Autosomal dominant mutations in the MAPT gene cause heterogeneous forms of frontotemporal lobar degeneration with tauopathy (FTLD-Tau). Common and rare variants in the MAPT gene increase the risk for sporadic FTLD-Tau, including progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD). We generated a collection of fibroblasts from 140 MAPT mutation/risk variant carriers, PSP, CBD, and cognitively normal controls; 31 induced pluripotent stem cell (iPSC) lines from MAPT mutation carriers, non-carrier family members, and autopsy-confirmed PSP patients; 33 genome engineered iPSCs that were corrected or mutagenized; and forebrain neural progenitor cells (NPCs). Here, we present a resource of fibroblasts, iPSCs, and NPCs with comprehensive clinical histories that can be accessed by the scientific community for disease modeling and development of novel therapeutics for tauopathies