419 research outputs found

    Aggression and performance in ice hockey

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    A SUSTAINABLE HERBICIDE AND GRASS ESTABLISHMENT APPROACH FOR LAND RECLAMATION: A CASE OF RUSSIAN KNAPWEED

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    Controlling Russian knapweed with an integrated system of herbicide followed by seeding perennial grass is profitable in yielding an 8.7% average rate of return, and repaying the establishment costs in approximately six years. Moreover, the system is sustainable by exploiting plant competition and eliminating herbicide usage in later years.Land Economics/Use,

    Determination of axial length, radius of curvature and lens size in the developing cat eye

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    Determination of axial length, radius of curvature and lens size in the developing cat ey

    A Morph-Based Simulated Annealing Heuristic for a Modified Bin-Packing Problem

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    This paper presents a local-search heuristic, based on the simulated annealing (SA) algorithm for a modified bin- packing problem (MBPP). The objective of the MBPP is to assign items of various sizes to a fixed number of bins, such that the sum-of-squared deviation (across all bins) from the target bin workload is minimized. This problem has a number of practical applications which include the assignment of computer jobs to processors, the assignment of projects to work teams, and infinite loading machine scheduling problems. The SA-based heuristic we developed uses a morph-based search procedure when looking for better allocations. In a large computational study we evaluated 12 versions of this new heuristic, as well as two versions of a previously published SA-based heuristic that used a completely random search. The primary performance measure for this evaluation was the mean percent above the best known objective value (MPABKOV). Since the MPABKOV associated with the best version of the random-search SA heuristic was more than 290 times larger than that of the best version of the morph-based SA heuristic, we conclude that the morphing process is a significant enhancement to SA algorithms for these problems

    The Purdue Agro-climatic (PAC) Dataset for The U.S. Corn Belt: Development and Initial Results

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    This study is a result of a project titled ā€˜ā€˜Useful to Usable (U2U): Transforming Climate Variability and Change Information for Cereal Crop Producersā€. This paper responds to the project goal to improve farm resiliency and proftability in the U.S. Corn Belt region by transforming existing meteorological dataset into usable knowledge and tools for the agricultural community. A high-resolution agro-climatic dataset that covers the U.S. Corn Belt was built for the U2U project based on a Land Data Assimilation System (LDAS) framework. This data referred to as the Purdue Agro-climatic (PAC) dataset is a gridded, continuous dataset suitable for agrocli- matic and crop model studies over the U.S. Corn Belt. The dataset was created at 4 km, sub- daily spatiotemporal resolution and covers the period of 1981ā€“2014. The dataset includes a range of variables such as daily maximum/minimum temperature, solar radiation, rainfall, evapotranspiration (ET), multilevel soil moisture and soil temperatures. The data were com- pared to feld measurements from Amerifux and the Soil Climate Analysis Network (SCAN), and with coarser but widely used atmospheric regional reanalysis data products. Validations indicate an overall good agreement between this dataset and feld measurements. The agree- ment is particularly high for radiation and temperature parameters and lesser for rainfall and soil moisture data. Despite the differences with observations, the data show improvements over the coarser resolution products and other available models and thus highlights the value of the dataset for agroclimatic and crop model studies. This high-resolution dataset is available to the wider community, and can fll gaps in observed data records and increase accessibility for the agricultural sector, and for conduct- ing variety of if-then assessments

    Lens and Retina Formation Require Expression of Pitx3 in Xenopus Pre-lens Ectoderm

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    Pitx3 is expressed in tissues fated to contribute to eye development, namely, neurula stage ectoderm and prechordal mesoderm, then presumptive lens ectoderm, placode, and finally lens. Pitx3 overexpression alters lens, optic cup, optic nerve, and diencephalon development. Many of the induced anomalies are attributable to midline deficits; however, as assessed by molecular markers, ectopic Pitx3 appears to temporarily enlarge the lens field. These changes are usually insufficient to generate either ectopic lenses to enlarge the eye that eventually differentiates. Conversely, use of a repressor chimera or of antisense morpholinos alters early expression of marker genes, and later inhibits lens development, thereby abrogating retinal induction. Reciprocal grafting experiments using wild-type and morpholino-treated tissues demonstrate that Pitx3 expression in the presumptive lens ectoderm is required for lens formation. Contradictory to recent assertions that retina can form in the absence of a lens, the expression of Pitx3 in the presumptive lens ectoderm. is critical for retina development

    Assessment of Toxicological Perturbations and Variants of Pancreatic Islet Development in the Zebrafish Model

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    The pancreatic islets, largely comprised of insulin-producing beta cells, play a critical role in endocrine signaling and glucose homeostasis. Because they have low levels of antioxidant defenses and a high perfusion rate, the endocrine islets may be a highly susceptible target tissue of chemical exposures. However, this endpoint, as well as the integrity of the surrounding exocrine pancreas, is often overlooked in studies of developmental toxicology. Disruption of development by toxicants can alter cell fate and migration, resulting in structural alterations that are difficult to detect in mammalian embryo systems, but that are easily observed in the zebrafish embryo model (Danio rerio). Using endogenously expressed fluorescent protein markers for developing zebrafish beta cells and exocrine pancreas tissue, we documented differences in islet area and incidence rates of islet morphological variants in zebrafish embryos between 48 and 96 h post fertilization (hpf), raised under control conditions commonly used in embryotoxicity assays. We identified critical windows for chemical exposures during which increased incidences of endocrine pancreas abnormalities were observed following exposure to cyclopamine (2ā€“12 hpf), Mono-2-ethylhexyl phthalate (MEHP) (3ā€“48 hpf), and Perfluorooctanesulfonic acid (PFOS) (3ā€“48 hpf). Both islet area and length of the exocrine pancreas were sensitive to oxidative stress from exposure to the oxidant tert-butyl hydroperoxide during a highly proliferative critical window (72 hpf). Finally, pancreatic dysmorphogenesis following developmental exposures is discussed with respect to human disease
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