Long Island University

About: Long Island University is a education organization based out in Brookville, New York, United States. It is known for research contribution in the topics: Population & Context (language use). The organization has 2647 authors who have published 4924 publications receiving 108757 citations.

Particle sorting in bivalves: in vivo determination of the pallial organs of selection

Abstract: Benthic particle feeders are exposed to a food supply varying in both quantity and quality. Previous studies have shown that bivalve molluscs deal with such fluctuating particle regimes in a variety of ways, including adjustments in pumping and ingestion rates, and selective rejection of non-nutritive particles as pseudofeces. The actual site of particle selection within the pallial cavity, however, has remained a topic of speculation. During August 1995 and January and August 1996, we exposed the oysters Crassostrea virginica (Gmelin) and C. gigas (Thunberg), and the mussel Mytilus trossulus Gould to a mixture of ground, aged Spartina alterniflora Loisel and similar-sized phytoplankton at three concentrations (103, 104, 105 particles ml−1). We then examined the ctenidia and labial palps by means of endoscopy and sampled, in vivo, the particulate material from various ciliated tracts, and analyzed the samples with a flow cytometer. We found that in oysters, the ctenidia are responsible for particle sorting, whereas the labial palps play an accessory role in particle selection, or function to control the volume of material to be ingested. In mussels, however, the ctenidia play little role in particle selection and simply transport particulate matter to the palps for further processing. We suggest that selection by the ctenidia of oysters is a function of their architecture (plicate, heterorhabdic).

A Theoretical and Empirical Review of the Contextual Interference Effect and the Learning of Motor Skills

Abstract: This paper addresses the contextual interference hypothesis, which was originally formulated by Battig (1966) and later adapted to motor learning by Shea and Morgan (1979). The hypothesis has generated much research, and its application has been readily suggested to practitioners. According to the hypothesis, high contextual interference (random practice) impairs acquisition but enhances retention and transfer, whereas low contextual interference (blocked practice) has the opposite effects. The empirical basis for the hypothesis—from laboratory-oriented and field-based settings—is examined. The generalizability of the hypothesis is also assessed. Recommendations are made for practitioners for optimal use of the contextual interference effect.

Deliquescence, Efflorescence, and Water Activity in Ammonium Nitrate and Mixed Ammonium Nitrate/Succinic Acid Microparticles

Abstract: Atmospheric aerosols have a direct impact on the earth’s radiation balance, an effect opposite in sign to that of the greenhouse gases. By scattering incoming solar radiation, either directly or indirectly as cloud particles, aerosols exert a cooling effect on the earth’s climate. In addition, they may provide catalytic sites for heterogeneous reactions to occur. The extent to which atmospheric particles will scatter light and be chemically reactive is directly related to their size, composition, and physical state. Tropospheric aerosols, both natural and anthropogenic in origin, are mostly composed of hygroscopic inorganic salts such as ammonium nitrate yet may contain organic compounds. These mixed particles may behave quite differently from the pure particles under changing relative humidity (RH) conditions. Therefore, in order to gain an understanding of these atmospheric processes and provide accurate input for regional climate models, it is imperative to understand the thermodynamics and kinetics of internally mixed particles under variable

A Continuous-Time Yield Management Model with Multiple Prices and Reversible Price Changes

Abstract: This article studies a continuous-time yield management model in which reversible price changes are allowed. We assume that perishable assets are offered at a set of discrete price levels. Demand at each level is a Poisson process. To maximize the expected revenue, management controls the price dynamically as sales evolve. We show that a subset of these prices that form a concave envelope is potentially optimal. We formulate the problem into an intensity control model and derive the optimal solution in closed form. Properties of the optimal solution and their policy implementations are discussed. Numerical examples are provided.

Protection of acetaminophen-induced hepatocellular apoptosis and necrosis by cholesteryl hemisuccinate pretreatment.

Abstract: This study of acetaminophen (AAP) hepatotoxicity examined whether some aspects of the highly integrated process of drug-induced toxicity involves apoptosis, in addition to necrosis in vivo; and if so, whether cholesteryl hemisuccinate (CS) pretreatment would selectively interfere with apoptotic or necrotic liver cell death. We have previously demonstrated that CS preexposure in vivo, protects hepatocellular necrosis and necrosis-related events induced by carbon tetrachloride (CCl4) administration. Our study demonstrates that administration of hepatotoxic doses of AAP (350-500 mg/kg, i.p.) to ICR mice (CD-1) results in severe liver injury leading to cell death both by necrosis and apoptosis. AAP-induced cell death was preceded by massive elevation in serum alanine aminotransferase coupled with rapid loss of large genomic DNA (2-24 hr), fragmentation of DNA in the form of a ladder (2-24 hr), apoptotic nuclear condensation at early hours (2-6 hr) followed by massive fragmentation and margination of heterochromatin at later (6-24) hours and a near total loss of glycogen in pericentral areas. Although CS (100 mg/kg, i.p.) alone had no noticeable biochemical or morphological effects, its administration before AAP (350-500 mg/kg, i.p.) abrogated histological and biochemical diagnostics of both apoptosis and necrosis. These include near total absence of loss of large genomic DNA and glycogen, and dramatic protection from escalating levels of liver injury. CS pretreatment also arrested AAP-induced ultrastructural changes typical of both apoptosis and necrosis. Histopathological examination of periodic acid-Schiff stained liver sections mirrored the biochemical and ultrastructural findings. In conclusion, this study for the first time establishes that apoptosis, in addition to necrosis, significantly contributes to AAP hepatotoxicity in vivo, and preexposure of mice to CS prevents AAP-induced hepatic apoptosis and necrosis.