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152010 full-text articles. Page 3628 of 3689.

Spatial Distribution Of Soda Straws Growth Rates Of The Coufin Cave (Vercors, France), Yves Perrette, Stéphane Jaillet 2010 Edytem, Université de Savoie - CNRS

Spatial Distribution Of Soda Straws Growth Rates Of The Coufin Cave (Vercors, France), Yves Perrette, Stéphane Jaillet

International Journal of Speleology

The Choranche Cave system (Vercors, France) is an excellent locality for measuring the growth rates of large numbers soda straws. This is especially the case for the Coufin Cave, as enlargement of the cave entrance in 1875 led to a change in stalactite color from brown to white, thus providing a reliable chronomarker. The date of this brown-to-white calcite transition has been confirmed by lamina counting. We measured and georeferenced the growth-lengths of 306 soda straws in a 1m2 area of the roof of the Coufin Cave entrance chamber. Because of the very slow and sometimes inexistent water feeding ...


Palaeomagnetic Research On Karst Sediments In Slovenia, Nadja Zupan Hajna, Andrej Mihevc, Petr Pruner, Pavel Bosàk 2010 Karst Research Institute

Palaeomagnetic Research On Karst Sediments In Slovenia, Nadja Zupan Hajna, Andrej Mihevc, Petr Pruner, Pavel Bosàk

International Journal of Speleology

We have conducted palaeomagnetic and magnetostratigraphic research on karst sediments in Slovenia since 1997. More than 2,000 samples were taken and analysed in 36 different profiles at 21 locations in caves and on the surface. Standard palaeomagnetic analyses were used (thermal and alternating field demagnetisation, magnetic susceptibility measurements, etc.). There is no evidence of younger marine deposition than Eocene in the SW part of Slovenia. Younger sediments occur only in caves and very rarely on the karst surface (different soils and a few remains of terrigeneous sediments). Marine and terrestrial Tertiary to Plio–Quaternary deposition occurs in the SE ...


Do Karst Rivers “Deserve” Their Own Biotic Index? A Ten Years Study On Macrozoobenthos In Croatia, Biljana Rađa, Sanja Puljas 2010 University of Split

Do Karst Rivers “Deserve” Their Own Biotic Index? A Ten Years Study On Macrozoobenthos In Croatia, Biljana Rađa, Sanja Puljas

International Journal of Speleology

In this study we present the results of a ten year survey of the aquatic macroinvertebrate fauna along four karst rivers: Jadro, Žrnovnica, Grab and Ruda, all of them situated in the Middle Dalmatia region of Croatia, in an attempt to construct the Iliric Biotic Index, which will be more applicable for the water quality analysis than the most frequently applied biotic index in Croatia, the Italian Modification of Extended Biotic Index. The rivers geologically belong to the Dinaric karst, unique geological phenomena in Europe. Benthic macroinvertebrates were collected along each river at 15 sites by standard methods of sampling ...


Age Frequency Distribution And Revised Stable Isotope Curves For New Zealand Speleothems: Palaeoclimatic Implications, Paul W. Williams, Helen L. Neil, Jian-Xin Zhao 2010 University of Auckland

Age Frequency Distribution And Revised Stable Isotope Curves For New Zealand Speleothems: Palaeoclimatic Implications, Paul W. Williams, Helen L. Neil, Jian-Xin Zhao

International Journal of Speleology

The occurrence of speleothems in New Zealand with reversed magnetism indicates that secondary calcite deposition in caves has occurred for more than 780 thousand years (ka). 394 uranium-series dates on 148 speleothems show that such deposition has taken place somewhere in the country with little interruption for more than 500 ka. A relative probability distribution of speleothem ages indicates that most growth occurred in mild, moist interglacial and interstadial intervals, a conclusion reinforced by comparing peaks and troughs in the distribution with time series curves of speleothem δ18O and δ13C values. The stable isotope time series ...


Karst Geology And Cave Fauna Of Austria: A Concise Review, Erhard Christian, Christoph Spötl 2010 University of Natural Resources and Applied Life Sciences, Vienna

Karst Geology And Cave Fauna Of Austria: A Concise Review, Erhard Christian, Christoph Spötl

International Journal of Speleology

The state of cave research in Austria is outlined from the geological and zoological perspective. Geologic sections include the setting of karst regions, tectonic and palaeoclimatic control on karst, modern cave environments, and karst hydrology. A chapter on the development of Austrian biospeleology in the 20th century is followed by a survey of terrestrial underground habitats, biogeographic remarks, and an annotated selection of subterranean invertebrates.


A Re-Appraisal Of The Stratigraphy, Palaeontology And Dating Of Cow Cave, Chudleigh, Devon, England, Jim W. Simons 2010 University of South Florida

A Re-Appraisal Of The Stratigraphy, Palaeontology And Dating Of Cow Cave, Chudleigh, Devon, England, Jim W. Simons

International Journal of Speleology

Cow Cave is an important Quaternary paleontological site in Chudleigh Gorge, Devon, UK., now known to have a sequence of cave-earths and stalagmite floors that range in age from Upper Middle Pleistocene (~MIS 7 interglacial) through to the Holocene (Flandrian) and the present day. Excavations in 1927-1934, and again in 1962-3, have provided a rich fauna, with some artefacts. Here, the stratigraphy of the deposits is now more fully described and the faunal remains are considered in their stratigraphical contexts. Data supporting the existence of former cave entrances are presented along with an analysis of the processes of sedimentation and ...


Toward A Whole-Landscape Approach For Sustainable Land Use In The Tropics, R. DeFries, C. Rosenzweig 2010 Columbia University

Toward A Whole-Landscape Approach For Sustainable Land Use In The Tropics, R. Defries, C. Rosenzweig

NASA Publications

Increasing food production and mitigating climate change are two primary but seemingly contradictory objectives for tropical landscapes. This special feature examines synergies and trade-offs among these objectives. Four themes emerge from the papers: the important roles of both forest and agriculture sectors for climate mitigation in tropical countries; the minor contribution from deforestation-related agricultural expansion to overall food production at global and continental scales; the opportunities for synergies between improved food production and reductions in greenhouse gas emissions through diversion of agricultural expansion to already-cleared lands, improved soil, crop, and livestock management, and agroforestry; and the need for targeted policy ...


Development And Evaluation Of A Cloud-Gap-Filled Modis Daily Snow-Cover Product, Dorothy K. Hall, George A. Riggs, James L. Foster, Sujay V. Kumar 2010 NASA Goddard Space Flight Center

Development And Evaluation Of A Cloud-Gap-Filled Modis Daily Snow-Cover Product, Dorothy K. Hall, George A. Riggs, James L. Foster, Sujay V. Kumar

NASA Publications

The utility of the Moderate Resolution Imaging Spectroradiometer (MODIS) snow-cover products is limited by cloud cover which causes gaps in the daily snow-cover map products. Wedescribe a cloud-gap-filled (CGF) daily snow-covermap using a simple algorithmto track cloud persistence, to account for the uncertainty created by the age of the snow observation. Developed from the 0.05° resolution climate-modeling grid daily snow-cover product,MOD10C1, each grid cell of the CGFmap provides a cloud-persistence count (CPC) that tellswhether the current or a prior day was used to make the snow decision. Percentage of grid cells “observable” is shown to increase dramatically when ...


Thermal Degradation Studies On Pmma–Het Acid Based Oligoesters Blends, Thangamani Rajkumar, Chinnaswamy Thangavel Vijayakumar, Palanichamy Sivasamy, Bojja Sreedhar, Charles Wilkie 2010 Kamaraj College of Engineering and Technology

Thermal Degradation Studies On Pmma–Het Acid Based Oligoesters Blends, Thangamani Rajkumar, Chinnaswamy Thangavel Vijayakumar, Palanichamy Sivasamy, Bojja Sreedhar, Charles Wilkie

Chemistry Faculty Research and Publications

Imparting thermal stability to polymethyl methacrylate (PMMA) without affecting its optical clarity is attempted by incorporating HET acid based oligoesters. Pure PMMA and PMMA containing five and 20 wt% of four different oligoesters are separately prepared using bulk polymerization. The thermal properties of the materials studied using DSC, TG, TG–FTIR and Pyr–GC–MS are presented. The main volatile degradation products identified are CO, HCl, CO2, H2O, hexachlorocyclopentadiene, hexachloroendomethylene tetrahydrophthalic acid/anhydride and methyl methacrylate. A detailed mechanism for the influence of the degradation products of HET acid based oligoesters on the thermal degradation of PMMA ...


Developing Performance Indicators To Evaluate The Management Effectiveness Of The Massachusetts Ocean Management Plan, Jack Wiggin, Dan Hellin, Kristin Uiterwyk, Robert E. Bowen, Prassede Vella, John Weber, Stephanie Moura, Nicholas Napoli, Kim Starbuck, Howard Krum 2010 University of Massachusetts Boston

Developing Performance Indicators To Evaluate The Management Effectiveness Of The Massachusetts Ocean Management Plan, Jack Wiggin, Dan Hellin, Kristin Uiterwyk, Robert E. Bowen, Prassede Vella, John Weber, Stephanie Moura, Nicholas Napoli, Kim Starbuck, Howard Krum

Urban Harbors Institute Publications

In June 2009, the Massachusetts Executive Office of Energy and Environmental Affairs (EEA) released its draft Massachusetts Ocean Management Plan (draft plan) for public comment. The plan is required by the Oceans Act of 2008 to, among other things, be adaptive to evolving knowledge and understanding of the ocean environment. The plan’s Science Framework establishes a blueprint for future research and data acquisition and ensuring that the plan evolves and its management measures adapt to this new and enhanced information. As stated in Chapter 5 of the draft plan, an important part of the science framework is the development ...


Folic Acid Source, Usual Intake, And Folate And Vitamin B-12 Status In Us Adults: National Health And Nutrition Examination Survey (Nhanes) 2003–2006, Quanhe Yang, Mary E. Cogswell, Heather C. Hamner, Alicia L. Carriquiry, Christine M. Pfeiffer, Robert J. Berry 2010 Centers for Disease Control and Prevention

Folic Acid Source, Usual Intake, And Folate And Vitamin B-12 Status In Us Adults: National Health And Nutrition Examination Survey (Nhanes) 2003–2006, Quanhe Yang, Mary E. Cogswell, Heather C. Hamner, Alicia L. Carriquiry, Christine M. Pfeiffer, Robert J. Berry

Statistics Publications

Background: US adults have access to multiple sources of folic acid. The contribution of these sources to usual intakes above the tolerable upper intake level (UL) (1000 ug/d) and to folate and vitamin B-12 status is unknown. Objective: The objective was to estimate usual folic acid intake above the UL and adjusted serum and red blood cell folate, vitamin B-12, methylmalonic acid, and homocysteine concentrations among US adults by 3 major folic acid intake sources - enriched cereal-grain products (ECGP), ready-to-eat cereals (RTE), and supplements (SUP) - categorized into 4 mutually exclusive consumption groups. Design: We used data from the National ...


Three-Phase Model Harmonizes Estimates Of The Maximal Suppression Of Parathyroid Hormone By 25-Hydroxyvitamin D In Persons 65 Years Of Age And Older, Ramon A. Durazo-Arvizu, Bess Dawson-Hughes, Christopher T. Sempos, Elizabeth A. Yetley, Anne C. Looker, Guichan Cao, Susan S. Harris, Vicki L. Burt, Alicia L. Carriquiry, Mary Frances Picciano 2010 Loyola University Chicago

Three-Phase Model Harmonizes Estimates Of The Maximal Suppression Of Parathyroid Hormone By 25-Hydroxyvitamin D In Persons 65 Years Of Age And Older, Ramon A. Durazo-Arvizu, Bess Dawson-Hughes, Christopher T. Sempos, Elizabeth A. Yetley, Anne C. Looker, Guichan Cao, Susan S. Harris, Vicki L. Burt, Alicia L. Carriquiry, Mary Frances Picciano

Statistics Publications

The concentration or threshold of 25-hydroxyvitamin D [25(OH)D] needed to maximally suppress intact serum parathyroid hormone (iPTH) has been suggested as a measure of optimal vitamin D status. Depending upon the definition of maximal suppression of iPTH and the 2-phase regression approach used, 2 distinct clusters for a single 25(OH)D threshold have been reported: 16-20 ng/mL (40-50 nmol/L) and 30-32 ng/mL (75-80 nmol/L). To rationalize the apparently disparate published results, we compared thresholds from several regression models including a 3-phase one to estimate simultaneously 2 thresholds before and after adjusting for possible ...


Effect Of Temperature And Nutrient Concentration On The Growth Of Six Species Of Sooty Blotch And Flyspeck Fungi, Jean C. Batzer, Sandra Hernandez Rincon, Daren S. Mueller, Benjamin J. Petersen, Fabien Le Corronc, Patricia S. McManus, Philip M. Dixon, Mark Gleason 2010 Iowa State University

Effect Of Temperature And Nutrient Concentration On The Growth Of Six Species Of Sooty Blotch And Flyspeck Fungi, Jean C. Batzer, Sandra Hernandez Rincon, Daren S. Mueller, Benjamin J. Petersen, Fabien Le Corronc, Patricia S. Mcmanus, Philip M. Dixon, Mark Gleason

Statistics Publications

We assessed the effects of temperature and nutrient concentration on the growth of commonly occurring members of the sooty blotch and flyspeck (SBFS) complex in the Midwest United States. Radial growth in vitro of two isolates of each of six SBFS species (Dissoconium aciculare, Colletogloeum sp. FG2, Peltaster sp. P2, Sybren sp. CS1, Pseudocercosporella sp. RH1, and Peltaster fructicola) was measured at 10, 15, 20, 25, 30 and 35°C for 7 weeks. Optimal growth for all six species occurred at 20 to 25°C, with slower growth at 10 and 15°C and little to no growth at 30 ...


Sustainability Of Glyphosate-Based Weed Management: The Benchmark Study, Michael D. Owen, Philip M. Dixon, David R. Shaw, Stephen C. Weller, Bryan G. Young, Robert G. Wilson, David L. Jordan 2010 Iowa State University

Sustainability Of Glyphosate-Based Weed Management: The Benchmark Study, Michael D. Owen, Philip M. Dixon, David R. Shaw, Stephen C. Weller, Bryan G. Young, Robert G. Wilson, David L. Jordan

Statistics Publications

One key to improved global crop production efficiency is the effective management of weeds, which are ranked as the number one crop pest by a majority of farmers1. This is no great surprise, as weeds are constantly evolving within the man-caused agroecosystems by adapting to high selection pressures imposed by crop production practices and, importantly, developing resistance to herbicides. Genetically engineered (GE) herbicide resistant (HR) crops facilitate better weed management and thus improved yields and more efficient use of resources, while minimizing risks to the environment (e.g., soil erosion). Since the commercial introduction of glyphosate resistant (GR) crops in ...


Finite Mixture Models And Model-Based Clustering, Volodymyr Melnykov, Ranjan Maitra 2010 North Dakota State University--Fargo

Finite Mixture Models And Model-Based Clustering, Volodymyr Melnykov, Ranjan Maitra

Statistics Publications

Finite mixture models have a long history in statistics, having been used to model population heterogeneity, generalize distributional assumptions, and lately, for providing a convenient yet formal framework for clustering and classification. This paper provides a detailed review into mixture models and model-based clustering. Recent trends as well as open problems in the area are also discussed.


A K-Mean-Directions Algorithm For Fast Clustering Of Data On The Sphere, Ranjan Maitra, Ivan Peter Ramler 2010 Iowa State University

A K-Mean-Directions Algorithm For Fast Clustering Of Data On The Sphere, Ranjan Maitra, Ivan Peter Ramler

Statistics Publications

A k-means-type algorithm is proposed for efficiently clustering data constrained to lie on the surface of a p-dimensional unit sphere, or data that are mean-zero-unit-variance standardized observations such as those that occur when using Euclidean distance to cluster time series gene expression data using a correlation metric. We also provide methodology to initialize the algorithm and to estimate the number of clusters in the dataset. Results from a detailed series of experiments show excellent performance, even with very large datasets. The methodology is applied to the analysis of the mitotic cell division cycle of budding yeast dataset of ...


Simulating Data To Study Performance Of Finite Mixture Modeling And Clustering Algorithms, Ranjan Maitra, Volodymyr Melnykov 2010 Iowa State University

Simulating Data To Study Performance Of Finite Mixture Modeling And Clustering Algorithms, Ranjan Maitra, Volodymyr Melnykov

Statistics Publications

A new method is proposed to generate sample Gaussian mixture distributions according to prespecified overlap characteristics. Such methodology is useful in the context of evaluating performance of clustering algorithms. Our suggested approach involves derivation of and calculation of the exact overlap between every cluster pair, measured in terms of their total probability of misclassification, and then guided simulation of Gaussian components satisfying prespecified overlap characteristics. The algorithm is illustrated in two and five dimensions using contour plots and parallel distribution plots, respectively, which we introduce and develop to display mixture distributions in higher dimensions. We also study properties of the ...


Electrically Driven Magnetism On A Pd Thin Film, Y. Sun, John D. Burton, Evgeny Y. Tsymbal 2010 University of Nebraska - Lincoln

Electrically Driven Magnetism On A Pd Thin Film, Y. Sun, John D. Burton, Evgeny Y. Tsymbal

Evgeny Tsymbal Publications

Using first-principles density-functional calculations, we demonstrate that ferromagnetism can be induced and modulated on an otherwise paramagnetic Pd metal thin-film surface through application of an external electric field. As free charges are either accumulated or depleted at the Pd surface to screen the applied electric field, there is a corresponding change in the surface density of states. This change can be made sufficient for the Fermi-level density of states to satisfy the Stoner criterion, driving a transition locally at the surface from a paramagnetic state to an itinerant ferromagnetic state above a critical applied electric field, Ec. Furthermore, due ...


Effect Of Spin-Dependent Screening On Tunneling Electroresistance And Tunneling Magnetoresistance In Multiferroic Tunnel Junctions, M. Ye. Zhuravlev, S. Maekawa, Evgeny Y. Tsymbal 2010 University of Nebraska - Lincoln

Effect Of Spin-Dependent Screening On Tunneling Electroresistance And Tunneling Magnetoresistance In Multiferroic Tunnel Junctions, M. Ye. Zhuravlev, S. Maekawa, Evgeny Y. Tsymbal

Evgeny Tsymbal Publications

Using a ferroelectric barrier as a functional material in a (magnetic) tunnel junction has recently attracted significant interest due to new functionalities not available in conventional tunnel junctions. Switching a ferroelectric polarization of the barrier alters conductance resulting in a tunneling electroresistance (TER) effect. Using a ferroelectric barrier in a magnetic tunnel junction makes it mutiferroic where TER coexists with tunneling magnetoresistance (TMR). Here we develop a simple model for a multiferroic tunnel junction (MFTJ) which consists of two ferromagnetic electrodes separated by a ferroelectric barrier layer. The model explicitly includes the spin-dependent screening potential and thus extends previously developed ...


Recommender System For Audio Recordings, Jong Seo Lee 2010 California Polytechnic State University - San Luis Obispo

Recommender System For Audio Recordings, Jong Seo Lee

Master's Theses and Project Reports

Nowadays the largest E-commerce or E-service websites offer millions of products for sale. A Recommender system is defined as software used by such websites for recommending commercial or noncommercial product items to users according to the users’ tastes. In this project, we develop a recommender system for a private multimedia web service company. In particular, we devise three recommendation engines using different data filtering methods – named weighted-average, K-nearest neighbors, and item-based – which are based on collaborative filtering techniques, which work by recording user preferences on items and by anticipating the future likes and dislikes of users by comparing the records ...


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