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Articles 2641 - 2670 of 3859

Full-Text Articles in Physical Sciences and Mathematics

Smart Grid Functionality Of A Pv-Energy Storage System, Nenad Damnjanovic Jan 2011

Smart Grid Functionality Of A Pv-Energy Storage System, Nenad Damnjanovic

USF Tampa Graduate Theses and Dissertations

Renewable Energy will be the key to preserving the Earth's remaining resources and continuing this surge of technological progress that we have experienced this past century. New philosophies of how/when/where energy should be consumed and produced are attempting to improve upon the current grid infrastructure. The massive advancement in communications, renewable and control systems will allow this new-age electric grid to maximize its efficiency while reducing cost. Renewable, "green" energy is now at the forefront of innovation. As the world population increases, there will be a need to free ourselves from natural resources as much as possible. Advanced Energy Storage …


Lead Discovery And Optimization Strategies Towards The Development Of 4(1h)-Quinolones And 1,2,3,4-Tetrahydroacridone Analogs With Antimalarial Activity, Richard Matthew Cross Jan 2011

Lead Discovery And Optimization Strategies Towards The Development Of 4(1h)-Quinolones And 1,2,3,4-Tetrahydroacridone Analogs With Antimalarial Activity, Richard Matthew Cross

USF Tampa Graduate Theses and Dissertations

The goal of our research endeavor was to successfully employ modern lead discovery and optimization strategies towards the development and identification of compounds possessing antimalarial activity. Preliminary data from in vitro screening at the Walter Reed Army Institute of Research identified several chemotypes including 4(1H)-quinolones and 1,2,3,4-tetrahydroacridones to have potent antimalarial activities. Multiple synthetic routes were devised and implemented which enabled the rapid preparation and isolation of over 400 structurally diverse 4(1H)-quinolones and 1,2,3,4-tetrahydroacridones.

Our research towards discovering and optimizing antimalarials was inspired from the severe impact malaria has had on our planet especially on impoverished countries. There are over …


Guanidines, Amidines And Carbamides As Novel Sigma Receptor Ligands For Post-Stroke Therapeutics, Michelle Yolanda Cortes-Salva Jan 2011

Guanidines, Amidines And Carbamides As Novel Sigma Receptor Ligands For Post-Stroke Therapeutics, Michelle Yolanda Cortes-Salva

USF Tampa Graduate Theses and Dissertations

Stroke is the 3rd leading cause of death in the United States. For this reason, it has become our goal to find a drug that is capable of reestablishing intracellular and extracellular Ca+2 flux upon direct binding to the sigma receptor, which can be delivered easily and efficiently. Our active research focuses the development of guanidine analogues that can serve as therapeutic drugs which target sigma 1 and sigma 2 receptors having a direct effect on Ca+2 levels on the cell. The use of symmetrical guanidine analogues such as N,N'-di-o-tolyl guanidine (o-DTG) as therapeutic drugs for ischemic …


Using A Focus Measure To Automate The Location Of Biological Tissue Surfaces In Brightfield Microscopy, Daniel Toby Elozory Jan 2011

Using A Focus Measure To Automate The Location Of Biological Tissue Surfaces In Brightfield Microscopy, Daniel Toby Elozory

USF Tampa Graduate Theses and Dissertations

The study of microstructures in brightfield microscopy using unbiased stereology plays a large and growing role in bioscience research. Stereology enables objective quantitative analysis of biological structures within a tissue sample. A first step in the stereology process is to calculate the thickness of a tissue sample by locating the top and bottom surfaces of the sample. The aim of this project is to fully automate this location process by using the relative optical focus measure as an indicator of tissue surface boundary.

The current method for identification of focus bounding planes requires a trained user to manually select the …


Automated Quantification Of Biological Microstructures Using Unbiased Stereology, Om Pavithra Bonam Jan 2011

Automated Quantification Of Biological Microstructures Using Unbiased Stereology, Om Pavithra Bonam

USF Tampa Graduate Theses and Dissertations

Research in many fields of life and biomedical sciences depends on the microscopic image analysis of biological images. Quantitative analysis of these images is often time-consuming, tedious, and may be prone to subjective bias from the observer and inter /intra observer variations. Systems for automatic analysis developed in the past decade determine various parameters associated with biological tissue, such as the number of cells, object volume and length of fibers to avoid problems with manual collection of microscopic data. Specifically, automatic analysis of biological microstructures using unbiased stereology, a set of approaches designed to avoid all known sources of systematic …


A Modeling Analysis Of Dissolved Carbon Dioxide Discharged From Howard F. Curren Advanced Wastewater Treatment Plant, Dustin Capps Jan 2011

A Modeling Analysis Of Dissolved Carbon Dioxide Discharged From Howard F. Curren Advanced Wastewater Treatment Plant, Dustin Capps

USF Tampa Graduate Theses and Dissertations

Currently, the US Environmental Protection Agency primarily regulates the discharge of dissolved nitrogen and phosphorous from wastewater treatment plants in the United States. A recent study has shown that the treated effluent of many plants contains concentrations of dissolved carbon dioxide well above the expected theoretical equilibrium concentration of 0.6 mg/L, indicating that carbon dioxide may have been overlooked as a possible pollutant in receiving waters. For this reason, it is necessary to examine the possible presence of a discharge plume containing high levels of dissolved CO2 downstream from the outfall of a major wastewater treatment plant in Tampa, Florida. …


Generalizations Of A Laplacian-Type Equation In The Heisenberg Group And A Class Of Grushin-Type Spaces, Kristen Snyder Childers Jan 2011

Generalizations Of A Laplacian-Type Equation In The Heisenberg Group And A Class Of Grushin-Type Spaces, Kristen Snyder Childers

USF Tampa Graduate Theses and Dissertations

In [2], Beals, Gaveau and Greiner find the fundamental solution to a 2-Laplace-type equation in a class of sub-Riemannian spaces. This fundamental solution is based on the well-known fundamental solution to the p-Laplace equation in Grushin-type spaces [4] and the Heisenberg group [6]. In this thesis, we look to generalize the work in [2] for a p-Laplace-type equation. After discovering that the "natural" generalization fails, we find two generalizations whose solutions are based on the fundamental solution to the p-Laplace equation.


Cover: Volume 40, Issue 1 Jan 2011

Cover: Volume 40, Issue 1

International Journal of Speleology

No abstract provided.


World Karst Science Reviews Jan 2011

World Karst Science Reviews

International Journal of Speleology

No abstract provided.


Alunite Formation Within Silica Stalactites From The Sydney Region, South-Eastern Australia, R. A.L. Wray Jan 2011

Alunite Formation Within Silica Stalactites From The Sydney Region, South-Eastern Australia, R. A.L. Wray

International Journal of Speleology

This paper presents X-ray diffraction and SEM evidence for the formation of alunite, and possibly small quantities of natroalunite, within opal-A stalactites formed on quartz sandstone near Sydney in south-eastern, Australia. Alunite has been reported as a speleogenetic mineral from sediments within a number of caves around the world, but this is believed to be the first report of speleothemic alunite in opaline silica speleothems. Individual alunite crystals have not been visually identified, but SEM X-ray element mapping suggests the alunite has formed amongst kaolinite clay. Sedimentary alunite and natroalunite formation is usually associated with the reaction of sulphuric acid …


Cover: Volume 40, Issue 2 Jan 2011

Cover: Volume 40, Issue 2

International Journal of Speleology

No abstract provided.


Mineralogy Of Iza Cave (Rodnei Mountains, N. Romania), Tudor Tămaş, Ferenc Kristály, Lucian Barbu-Tudoran Jan 2011

Mineralogy Of Iza Cave (Rodnei Mountains, N. Romania), Tudor Tămaş, Ferenc Kristály, Lucian Barbu-Tudoran

International Journal of Speleology

The secondary minerals from Iza Cave result from the interactions of karst water and/or cave atmosphere over a variety of sedimentary and metamorphic rocks. The cave passages expose at various extents Eocene limestones and conglomerates, Oligocene black shales, Upper Precambrian micaschists, marble and dolomitic marble and associated ore deposits.

Twelve secondary minerals identified in the cave (carbonates, sulfates, phosphates, oxides and hydroxides, and silicates) are presented in this study. Calcite, aragonite, gypsum, brushite and hydroxylapatite are the components of common speleothems in the limestone, dolomite and conglomerate areas of the cave. Ankerite crusts are related to areas with pyrite mineralization …


The Subterranean Fauna Of A Biodiversity Hotspot Region - Portugal: An Overview And Its Conservation, Ana Sofia P.S. Reboleira, Paulo A.V. Borges, Fernando Gonçalves, Artur R.M. Serrano, Pedro Oromí Jan 2011

The Subterranean Fauna Of A Biodiversity Hotspot Region - Portugal: An Overview And Its Conservation, Ana Sofia P.S. Reboleira, Paulo A.V. Borges, Fernando Gonçalves, Artur R.M. Serrano, Pedro Oromí

International Journal of Speleology

An overview of the obligate hypogean fauna in Portugal (including Azores and Madeira archipelagos) is provided, with a list of obligated cave-dwelling species and subspecies, and a general perspective about its conservation. All the available literature on subterranean Biology of Portugal since the first written record in 1870 until today has been revised. A total of 43 troglobiont and 67 stygobiont species and subspecies from 12 orders have been described so far in these areas, included in the so-called Mediterranean hotspot of biodiversity. The subterranean fauna in Portugal has been considered moderately poor with some endemic relicts and it remains …


Book Review: Aspects Of The History Of Slovene Karst 1545 – 2008, Arrigo A. Cigna Jan 2011

Book Review: Aspects Of The History Of Slovene Karst 1545 – 2008, Arrigo A. Cigna

International Journal of Speleology

No abstract provided.


In Situ Acetylene Reduction Activity Of Scytonema Julianum In Vapor Cave (Spain), Antonia Dolores Asencio, Marina Aboal Jan 2011

In Situ Acetylene Reduction Activity Of Scytonema Julianum In Vapor Cave (Spain), Antonia Dolores Asencio, Marina Aboal

International Journal of Speleology

Nitrogen fixation was measured in situ for the first time by acetylene reduction for a greyish mat composed of Scytonema julianum in cave-like environments. Mat-specific rates (129.9-215.7 nmol C2 H4 m-2 s-1 for daytime fixation and 65.1-120.6 nmol C2 H4 m-2 s-1 for nighttime fixation) recorded in the Vapor cave differed considerably due to the energy reserves stored during photosynthesis being exhausted and used in the dark phase. The most influential environmental parameter for nitrogen fixation in the Vapor cave is temperature in the daytime and nighttime fixations. Nitrogen fixation by cyanobacteria may contribute considerably to the overall nitrogen cycle …


Iron Oxide And Calcite Associated With Leptothrix Sp. Biofilms Within An Estavelle In The Upper Floridan Aquifer, Lee J. Florea, Chasity L. Stinson, Josh Brewer, Rick Fowler, B Joe Kearns, Anthony M. Greco Jan 2011

Iron Oxide And Calcite Associated With Leptothrix Sp. Biofilms Within An Estavelle In The Upper Floridan Aquifer, Lee J. Florea, Chasity L. Stinson, Josh Brewer, Rick Fowler, B Joe Kearns, Anthony M. Greco

International Journal of Speleology

In Thornton’s Cave, an estavelle in west-central Florida, SEM, EDS, and XRD data reveal biofilms that are predominantly comprised of FeOOH-encrusted hollow sheaths that are overgrown and intercalated with calcite. Fragments of this crystalline biofilm adhere to the walls and ceiling as water levels vary within the cave. Those on the wall have a ‘cornflake’ appearance and those affixed to the ceiling hang as fibrous membranes. PCR of DNA in the active biofilm, combined with morphologic data from the tubes in SEM micrographs, point to Leptothrix sp., a common Fe-oxidizing bacteria, as the primary organism in the biofilm. Recent discoveries …


Editorial, Carol A. Hill Jan 2011

Editorial, Carol A. Hill

International Journal of Speleology

No abstract provided.


A Note On The Occurrence Of A Crayback Stalagmite At Niah Caves, Borneo, Joyce Lundberg, Donald A. Mcfarlane Jan 2011

A Note On The Occurrence Of A Crayback Stalagmite At Niah Caves, Borneo, Joyce Lundberg, Donald A. Mcfarlane

International Journal of Speleology

Crayback stalagmites have mainly been reported from New South Wales, Australia. Here we document a small crayback in the entrance of Painted Cave (Kain Hitam), part of the Niah Caves complex in Sarawak, Borneo. Measuring some 65 cm in length and 18 cm in height, this deposit is elongate in the direction of the dominant wind and thus oriented towards the natural tunnel entrance. It shows the classic humpbacked long profile, made up of small transverse segments or plates, in this case the tail extending towards the entrance. The dark blue-green colour down the centre suggests that cyanobacterial growth follows …


Table Of Contents Jan 2011

Table Of Contents

International Journal of Speleology

No abstract provided.


Book Review: Karst Rock Feature Karren Sculpturings, Jo De Waele Jan 2011

Book Review: Karst Rock Feature Karren Sculpturings, Jo De Waele

International Journal of Speleology

No abstract provided.


World Karst Science Reviews Jan 2011

World Karst Science Reviews

International Journal of Speleology

No abstract provided.


Book Review: Advances In Research In Karst Media, Bartolomé Andreo Navarro Jan 2011

Book Review: Advances In Research In Karst Media, Bartolomé Andreo Navarro

International Journal of Speleology

No abstract provided.


Eogenetic Caves In Conglomerate: An Example From Udin Boršt, Slovenia, Matej Lipar, Mateja Ferk Jan 2011

Eogenetic Caves In Conglomerate: An Example From Udin Boršt, Slovenia, Matej Lipar, Mateja Ferk

International Journal of Speleology

Udin Boršt is a karstified terrace of carbonate rock, which is of fluvioglacial origin, and is situated in the north-western part of Slovenia. There are 15 registered caves, which have been interpreted as caves in conglomerate, while karst of Udin Boršt itself was interpreted as conglomerate karst, shallow karst or isolated karst. In this article, caves in Udin Boršt have been interpreted as eogenetic caves. Based on porosity and bedding material, different types of caves and cave passages have developed. Four general types of eogenetic caves found in Udin Boršt are; linear stream caves, shelter caves, breakdown caves and vadose …


Comparison Of 14c And U-Th Ages Of Two Holocene Phreatic Overgrowths On Speleothems From Mallorca (Western Mediterranean): Environmental Implications, Paola Tuccimei, Mark Van Strydonck, Angel Ginés, Joaquín Ginés, Michele Soligo, Igor M. Villa, Joan J. Fornós Jan 2011

Comparison Of 14c And U-Th Ages Of Two Holocene Phreatic Overgrowths On Speleothems From Mallorca (Western Mediterranean): Environmental Implications, Paola Tuccimei, Mark Van Strydonck, Angel Ginés, Joaquín Ginés, Michele Soligo, Igor M. Villa, Joan J. Fornós

International Journal of Speleology

This investigation reports on the comparison between ICP-MS U-Th and AMS 14C ages of Phreatic Overgrowths on Speleothems (POS) from two different caves on the island of Mallorca (Spain). These speleothem encrustations form at the water table of coastal caves in a low-amplitude tide-controlled microenvironment and are used to reconstruct past sea level changes. The aim of this study is to evaluate if this particular type of speleothem is datable using 14C method and to investigate possible problems connected with the incorporation of dead carbon inherited from the dissolution of 14C-free limestone. The results show that 14C ages are strongly …


Editorial, Jo De Waele Jan 2011

Editorial, Jo De Waele

International Journal of Speleology

No abstract provided.


Secondary Halite Deposits In The Iranian Salt Karst: General Description And Origin, Michal Filippi, Jiří Bruthans, Lukáš Palatinus, Mohammad Zare, Naser Asadi Jan 2011

Secondary Halite Deposits In The Iranian Salt Karst: General Description And Origin, Michal Filippi, Jiří Bruthans, Lukáš Palatinus, Mohammad Zare, Naser Asadi

International Journal of Speleology

This paper summaries 12 years of documentation of secondary halite deposits in the Iranian salt karst.

A variety of secondary halite deposits was distinguished and classified into several groups, on the basis of the site and mechanism of their origin. Deposits formed: i) via crystallization in/on streams and pools, ii) from dripping, splashing and aerosol water, iii) from evaporation of seepage and capillary water, and iv) other types of deposits. The following examples of halite forms were distinguished in each of the above mentioned group: i) euhedral crystals, floating rafts (raft cones), thin brine surface crusts and films; ii) straw …


The Present Day Genesis And Evolution Of Cave Minerals Inside The Ojo De La Reina Cave (Naica Mine, Mexico), Giovanni Badino, José Maria Calaforra, Paolo Forti, Paolo Garofalo, Laura Sanna Jan 2011

The Present Day Genesis And Evolution Of Cave Minerals Inside The Ojo De La Reina Cave (Naica Mine, Mexico), Giovanni Badino, José Maria Calaforra, Paolo Forti, Paolo Garofalo, Laura Sanna

International Journal of Speleology

Ojo de la Reina is the first and the smallest cave intersected at the -290 level in the Naica Mine (Mexico), therefore it was the first cavity in which the lowering of temperature induced by mine ventilation caused condensation over crystals’ surface since 2005. The consequent dissolution of the gypsum crystals and subsequent condensed water evaporation lead to the deposition of several new minerals, among which some highly soluble Mg/Na compounds (bloedite, epsomite, halite, hexahydrite, kieserite, starkeyite). The single available source of Mg and Na ions in this minerogenetic environment is represented by the huge fluid inclusions widespread within the …


Trace Element And Stable Isotope Data From A Flowstone In A Natural Cave Of The Mining District Of Sw Sardinia (Italy): Evidence For Zn²⁺-Induced Aragonite Precipitation In Comparatively Wet Climatic Conditions, Guglielmo Angelo Caddeo, Jo De Waele, Franco Frau, Loren Bruce Railsback Jan 2011

Trace Element And Stable Isotope Data From A Flowstone In A Natural Cave Of The Mining District Of Sw Sardinia (Italy): Evidence For Zn²⁺-Induced Aragonite Precipitation In Comparatively Wet Climatic Conditions, Guglielmo Angelo Caddeo, Jo De Waele, Franco Frau, Loren Bruce Railsback

International Journal of Speleology

A speleothem from Crovassa Azzurra, a mine cave in SW Sardinia (Italy), has been analysed for mineralogy, minor and trace elements and stable isotopes. It is composed of layers of primary calcite and aragonite, with a region of secondary calcite. The primary carbonate is strikingly rich in Zn and Pb, presumably as the result of transport in solution from overlying Pb-Zn deposits. Immediately below the transition between calcite and aragonite, concentrations of Zn, Cd and P increase. At the transition between aragonite and Pb-rich aragonite, concentrations of Pb and P increase. Stable isotopes indicate an evolution toward more humid periods …


Minerogenetic Mechanisms Occurring In The Cave Environment: An Overview, Bogdan P. Onac, Paolo Forti Jan 2011

Minerogenetic Mechanisms Occurring In The Cave Environment: An Overview, Bogdan P. Onac, Paolo Forti

International Journal of Speleology

Perhaps man’s first motivation to explore caves, beyond using them as shelter, was the search for substances that were not available elsewhere: most of them were minerals. However, for a long time it was believed that the cave environment was not very interesting from the mineralogical point of view. This was due to the fact that most cave deposits are normally composed of a single compound: calcium carbonate. Therefore, the systematic study of cave mineralogy is of only recent origin. However, although only a limited number of natural cavities have been investigated in detail, about 350 cave minerals have already …


Revisiting Three Minerals From Cioclovina Cave (Romania), Bogdan P. Onac, Herta S. Effenberger, Nathan C. Collins, Joe B. Kearns, Radu C. Breban Jan 2011

Revisiting Three Minerals From Cioclovina Cave (Romania), Bogdan P. Onac, Herta S. Effenberger, Nathan C. Collins, Joe B. Kearns, Radu C. Breban

International Journal of Speleology

Cioclovina Cave in Romania’s Southern Carpathians is a world-renowned cave site for its paleontological, anthropological, and mineralogical (type locality of ardealite) findings. To date, over 25 mineral species have been documented, some unusual for a cave environment. This paper presents details on the occurrence of collinsite [Ca2(Mg,Fe2+)(PO4)2·2H2O], atacamite [Cu22+Cl(OH)3], and kröhnkite [Na2Cu2+(SO4)2·2H2O] based on single-crystal X-ray diffraction, electron microprobe, stable isotope analyses, and scanning electron microscope imaging. This is the first reported occurrence of kröhnkite …