16,365 research outputs found

    Alluvial to lacustrine sedimentation in an endorheic basin during the Mio-Pliocene: The Toro Negro Formation, Central Andes of Argentina

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    A 2400 m-thick sedimentary column belonging to the Toro Negro Formation was recorded along the Quebrada del Yeso, Sierra de Los Colorados (Vinchina Basin), La Rioja province, NW Argentina. The Vinchina basin is a good example of a closed basin surrounded by the Precordillera fold and thrust belt to the west and basement-cored blocks to the north, south (Western Sierras Pampeanas) and east (Sierra de Famatina). Seven facies associations (FA) are described and interpreted to represent fluvial, lacustrine and alluvial environments developed in the southern part of the Vinchina basin from the Late Miocene until the earliest Pleistocene. The depositional evolution of the formation was divided in four phases. Phase I (∼7–6.6 Ma) represents sedimentation in medial (FA I) to distal (FA II) parts of a southward directed distributive fluvial system with a retrogradational pattern. During phase II (6.6–6.1Ma), the distributive fluvial system was replaced by a mixed clastic-evaporitic shallow lake (FA III) in a high aggradational basin. In phase III (∼6.1–5 Ma) the eastward progradation of a fluvial system (FA IV) was recorded as a distal clastic wedge. Finally, phase IV (∼5-2.4Ma) records two depositional cycles of proximal clastic wedge progradation of fluvial-dominated piedmonts (FAV, FAVII) from the southwest (Sierra de Umango) and/or the west (Precordillera) with an intervening playa lake (FA VI). Two new U-Pb ages obtained from zircons in volcanic ash layers confirm the Late Miocene age of the lower member of the Toro Negro Formation and permit a tight correlation with the central part of the basin (Quebrada de La Troya section). The sedimentation rate calculated for the dated lacustrine-fluvial interval is higher than the corresponding one in La Troya area suggesting a higher subsidence in the southern part of the basin. During the Late Miocene (∼7-6.6Ma) the ephemeral drainage was controlled by an arid to semiarid climate and initially dissipated mostly internally as terminal fan/distributive fluvial systems descending from the north. A thick lacustrine interval developed in the southern part of the basin between ∼6.6 and 6.1 Ma during a period of high subsidence and closed drainage. Besides, this interval coincides with increased aridity recorded in other basins in the Northwest of Argentina. By ∼6.1 Ma the area started to receive the first coarse-grained sediments heralding the progradation of a clastic wedge from the southwest-west (Sierra de Umango and Precordillera) which fully developed during the rest of the Pliocene to the earliest Pleistocene (∼5–2.4 Ma). The 6.1–2.4 Ma interval records ameliorating climate conditions.Fil: Ciccioli, Patricia Lucia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; ArgentinaFil: Marenssi, Sergio Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; ArgentinaFil: Amidon, William H.. Middlebury College; Estados UnidosFil: Limarino, Carlos Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; ArgentinaFil: Kylander Clark, Andrew. University of California; Estados Unido

    Current and evolving approaches for improving the oral permeability of BCS Class III or analogous molecules

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    The Biopharmaceutics Classification System (BCS) classifies pharmaceutical compounds based on their aqueous solubility and intestinal permeability. The BCS Class III compounds are hydrophilic molecules (high aqueous solubility) with low permeability across the biological membranes. While these compounds are pharmacologically effective, poor absorption due to low permeability becomes the rate-limiting step in achieving adequate bioavailability. Several approaches have been explored and utilized for improving the permeability profiles of these compounds. The approaches include traditional methods such as prodrugs, permeation enhancers, ion-pairing, etc., as well as relatively modern approaches such as nanoencapsulation and nanosizing. The most recent approaches include a combination/hybridization of one or more traditional approaches to improve drug permeability. While some of these approaches have been extremely successful, i.e. drug products utilizing the approach have progressed through the USFDA approval for marketing; others require further investigation to be applicable. This article discusses the commonly studied approaches for improving the permeability of BCS Class III compounds

    Indexing with coded deltas—a data compaction technique

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    The paper describes the coded delta scheme, which is one of the methods used by the Census Research Unit, University of Durham, for compacting the 1971 U.K. census data. It evaluates the merits and limitations of the technique in relation to the characteristics of the data set and other techniques available for compact encoding of numeric and string data

    Morris student spends summer working for positive parenting organization

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    Amidon, ’12, Falcon Heights, works for DREAM for Kids

    THE LOGISTICAL COSTS OF MARKETING IDENTITY PRESERVED WHEAT

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    This study examines prospective additional costs associated with identity preserved (IP) transactions and their allocation among participants in the wheat marketing system (farmers, grain handlers, and millers). Cost allocations for participants are computed across a range of potential specifications for IP transactions. As strategies become more specific (moved toward either location, variety, or variety and location), the probability of lots meeting quality specifications for the desired end-use characteristic (absorption) generally increased and changes in costs for mills declined. The exception is for strategies that include varieties which involve a premium paid by millers. As strategies become more specific, higher economic costs are imposed on shippers. These economic costs are substantial and provide incentives for shippers to develop techniques that would allow segregation of lots based on quality to recapture this unrealized value. The other change in costs among participants is the shifting of revenue to farmers from mills for variety specific strategies. This analysis indicates that when the desired quality characteristic is absorption, premiums paid for specific varieties quickly offset any reduction in procurement costs achieved by mills.identity preserved, wheat, quality, growers, grain handlers, end-users, Crop Production/Industries,

    Critical powder loading and the rheology of nanosized cemented carbide with titanium carbide as grain growth inhibitor for injection molding

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    The purpose of this paper is to determine the critical powder loading of WC-Co and to study the effect of TiC powder on the rheological behavior of MIM feedstock. WC-TiC-6Co metal powder was taken as raw material. 60% (mass fraction) palm stearin and 40% low density polyethylene were employed as binders to prepare injection feedstock. Three feedstocks were prepared at different TiC % loadings of 0.5, 0.75, and 1.0 (by weight). A homogeneous metal powders is formed by using ball mill mixer and mixed together with binder system by using Brabender mixer. Based on the result obtained, it was concluded that feedstock with 0.75 wt. % TiC powder show a good pseudo-plastic behavior within acceptable ranges in MIM

    Vitamin D3-loaded electrospun cellulose acetate/polycaprolactone nanofibers: Characterization, in-vitro drug release and cytotoxicity studies

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    Vitamin D deficiency is nowa global health problem; despite several drug delivery systems for carrying vitaminD due to low bioavailability and loss bioactivity. Developing a new drug delivery system to deliver vitamin D3 is a strong incentive in the current study. Hence, an implantable drug delivery system (IDDS) was developed from the electrospun cellulose acetate (CA) and ε-polycaprolactone (PCL) nanofibrous membrane, in which the core of implants consists of vitamin D3-loaded CA nanofiber (CAVD) and enclosed in a thin layer of the PCL membrane (CAVD/PCL). CA nanofibrousmat loadedwith vitaminD3 at the concentrations of 6, 12, and 20% (w/w) of vitamin D3 were produced using electrospinning. The smooth and bead-free fibers with diameters ranged from 324 to 428 nm were obtained. The fiber diameters increased with an increase in vitamin D3 content. The controlled drug release profile was observed over 30-days, which fit with the zero-order model (R2 > 0.96) in the first stage. The mechanical properties of IDDS were improved. Young's modulus and tensile strength of CAVD/PCL (dry) were161 ± 14 and 13.07 ± 2.5 MPa, respectively. CA and PCL nanofibers are non-cytotoxic based on the results of the in-vitro cytotoxicity studies. This study can further broaden in-vivo study and provide a reference for developing a new IDDS to carry vitamin D3 in the future

    Range Extensions in North American Hispinae (Coleoptera: Chrysomelidae)

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    Thirty-nine new state or provincial records are presented for 22 species of North American Hispinae
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