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2011

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Articles 9571 - 9600 of 10325

Full-Text Articles in Physical Sciences and Mathematics

Geomicrobiology Of Louisiana Coastal Marshes Before And After The Deepwater Horizon Oil Spill, Chang Liu Jan 2011

Geomicrobiology Of Louisiana Coastal Marshes Before And After The Deepwater Horizon Oil Spill, Chang Liu

LSU Master's Theses

The 2010 Deepwater Horizon oil spill in the Gulf of Mexico not only impacted open ocean and shoreline geochemical and ecological environments, but it served to promote research of microbial ecosystems in poorly studied habitats, such as Louisiana marshes. Sediment and water samples from four main marshes in southern Louisiana were collected in May 2010 (pre-oil), September 2010 (oiled), and June 2011 (post-oil). Sites near the Mississippi River had exceptionally low salinity in the immediate months following the oil spill due to freshwater diversion efforts; salinity increased by an order of magnitude one year later. Microbial diversity was evaluated from …

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Fraction Proficiency In Gifted Middle School Students, Lauren Alissa Lejeune Jan 2011

Fraction Proficiency In Gifted Middle School Students, Lauren Alissa Lejeune

LSU Master's Theses

This thesis presents a program to develop fraction proficiency in gifted students who have skipped grades. The program was piloted with 31 gifted and advanced students in grades 6 and 7, and qualitative data on their performance is presented. Also presented here is a test of fraction proficiency that was developed to determine the level that students achieved at the end of the pilot program. The results of this test are presented and analyzed. The net contribution of this work is to present a starting point for a set of catch-up lessons on operations with fractions and to present a …

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Spatiotemporal Responses Of Macroinvertebraes To Timber Harvesting In Low-Gradient Headwater Streams Of Central Louisiana, Derrick Klimesh Jan 2011

Spatiotemporal Responses Of Macroinvertebraes To Timber Harvesting In Low-Gradient Headwater Streams Of Central Louisiana, Derrick Klimesh

LSU Master's Theses

Macroinvertebrates are reflective of their nearby environment and are popularly used to detect changes in water quality. In this thesis research, macroinvertebrates were collected to investigate aquatic effects of timber harvesting operations with and without the use of best management practices (BMPs) in a forested, low-gradient, subtropical watershed in central Louisiana. Habitat assessments, physicochemical and hydrologic measurements, and macroinvertebrate sampling were conducted nine times from 2006 to 2010 during the spring and late summer, at 13 site locations ranging from plot level to watershed outlet. Timber harvesting occurred in September of 2007. A total of 86,183 macroinvertebrates were identified from …

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Fate Of Mississippi River Diverted Nitrate On Vegetated And Non-Vegetated Coastal Marshes Of Breton Sound Estuary, Christine M. Vanzomeren Jan 2011

Fate Of Mississippi River Diverted Nitrate On Vegetated And Non-Vegetated Coastal Marshes Of Breton Sound Estuary, Christine M. Vanzomeren

LSU Master's Theses

The Caernarvon Diversion meters Mississippi River water into coastal marshes of Breton Sound. Elevated levels of nitrogen in river water have sparked concerns that nutrient loading may affect marsh resilience and belowground biomass, as evidence from several marsh fertilization studies. These concerns resulted from observation that fresh and brackish Breton Sound marshes suffered extensive damage from Hurricane Katrina. The goal of this study is to determine the fate of nitrate (the dominant inorganic nitrogen form in the Mississippi River) in Breton Sound Estuary marshes. We hypothesized that most nitrate would be removed by denitrification and that nitrate loading would not …

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Temporal Changes In Quality Of Life And Environment In New Orleans After Hurricane Katrina, Danielle Johanna Larock Jan 2011

Temporal Changes In Quality Of Life And Environment In New Orleans After Hurricane Katrina, Danielle Johanna Larock

LSU Master's Theses

Understanding and assessing the spatial and temporal changes of quality of life and environment of a community is critical to its sustainable development, especially after a disaster strikes. This study explores an approach that integrates remote sensing with socioeconomic data to assess the temporal changes in quality of life and environment (QOL) using Orleans Parish as an example. Hurricane Katrina, which struck New Orleans in 2005, has had vast implications economically, socially, and environmentally for this city and the surrounding area. Empirically quantifying these concepts will help to rebuild the city more sustainably. This study investigated change in environmental quality …

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Factors Structuring Zooplankton Density And Composition Within A Louisiana River And Floodplain Tributaries With Emphasis On Hydrologic Processes, William Lowe Sheftall Iv Jan 2011

Factors Structuring Zooplankton Density And Composition Within A Louisiana River And Floodplain Tributaries With Emphasis On Hydrologic Processes, William Lowe Sheftall Iv

LSU Master's Theses

Zooplankters are important members of freshwater communities, facilitating the transfer of energy from primary production to higher trophic levels. Lentic floodplain systems are important in providing zooplankters with adequate habitat for growth and reproduction. Recently, The Nature Conservancy has been interested in cataloguing the aquatic taxa that inhabit the Ouachita River and floodplain in northern Louisiana, concurrent with an attempt to reestablish a river-floodplain connection with the river and eastern floodplain (the Mollicy Farms Unit, part of the Upper Ouachita National Wildlife Refuge). Sampling was conducted at seven sites along the Ouachita River and western floodplain monthly for one year …

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Evaluation Of Selected Plant Products As Dietary Protein Sources For Florida Pompano (Trachinotus Carolinus), Gregory Lech Jan 2011

Evaluation Of Selected Plant Products As Dietary Protein Sources For Florida Pompano (Trachinotus Carolinus), Gregory Lech

LSU Master's Theses

Profitability of aquaculture enterprises worldwide has been affected by rising fish meal prices. Plant proteins are promising replacements for fish meal because of their lower cost and worldwide availability. The goal of this research was to provide nutritional information for the development of all-plant diets for Florida pompano by evaluating growth of fish fed soy-based, fish-meal-free diets and assessing the nutritional value of several plant protein sources. In the first experiment, juvenile Florida pompano were fed five, soy-based, fish-meal-free diets containing graded levels of soybean meal (SBM, or M) at 0, 20, 25, 30, or 35%, with the remaining protein …

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A Look At The Integration Of Wetlands And Hazard Mitigation Planning In Coastal Louisiana, Kathleen Melissa Bowers Jan 2011

A Look At The Integration Of Wetlands And Hazard Mitigation Planning In Coastal Louisiana, Kathleen Melissa Bowers

LSU Master's Theses

Due to the destruction of the damaging hurricanes of 2005, Katrina and Rita, more effort has gone into the rebuilding and prevention of future disasters along the Louisiana coast than ever before. This research focuses on the use of wetlands, in the ten coastal parishes of Louisiana, as a mitigation effort aiding in the protection of coastal communities. Using content analysis and decision support software, a wetland ranking was created that represents how wetlands are utilized and protected within each parish. Criteria gathered from the plans include how many times wetlands were mentioned, collaboration with the state and other agencies, …

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Response Of Disturbance-Dependent Breeding Bird Communities To Two Site Preparations In Loblolly Pine Plantations, Falyn Leann Owens Jan 2011

Response Of Disturbance-Dependent Breeding Bird Communities To Two Site Preparations In Loblolly Pine Plantations, Falyn Leann Owens

LSU Master's Theses

Disturbance-dependent birds throughout the United States have recently experienced significant declines due to fire suppression and conversion of wilderness to human-dominated landscapes. In Louisiana, young loblolly pine plantations are an important source of early- successional habitat for these specialist birds. However, changes in management practices may affect forest stand suitability for bird communities that rely on them. Here I examined how changes in two site preparations, tree row spacing [14 ft (4.3 m) vs. 20 ft (6.1 m)] and arrangement of post-harvest woody debris (piled vs. scattered), impacted breeding, disturbance- dependent birds. During four summers in 2006-2010, observers conducted point …

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Parallel Surrogate Detection In Large-Scale Simulations, Lei Jiang Jan 2011

Parallel Surrogate Detection In Large-Scale Simulations, Lei Jiang

LSU Master's Theses

Simulation has become a useful approach in scientific computing and engineering for its ability to model real natural or human systems. In particular, for complex systems such as hurricanes, wildfire disasters, and real-time road traffic, simulation methods are able to provide researchers, engineers and decision makers predicted values in order to help them to take appropriate actions. For large-scale problems, the simulations usually take a lot of time on supercomputers, thus making real-time predictions more difficult. Approximation models that mimic the behavior of simulation models but are computationally cheaper, namely "surrogate models", are desired in such scenarios. In the thesis, …

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Decay Of A Negative Molecular Ion In A Constant Electric Field, S. V. Borzunov, N. L. Manakov, Anthony F. Starace, M. V. Frolov Jan 2011

Decay Of A Negative Molecular Ion In A Constant Electric Field, S. V. Borzunov, N. L. Manakov, Anthony F. Starace, M. V. Frolov

Anthony F. Starace Publications

The problem of the shift and broadening of the electron energy levels in the field of two 3D short-range potentials (e.g., the model of a negative molecular ion) by a constant electric field F is considered. The interaction of an electron with attraction centers is taken into account in the effective range approximation. We analyze the cases when both centers maintain weakly bound s states and when the electron state in the field of one of the centers is a p state. Exact numerical results for the shift and the width of the energy levels of a quasi-molecule as functions …

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Synthesis Of Alkynyl Ribofuranosides, Christian Rodriguez Jan 2011

Synthesis Of Alkynyl Ribofuranosides, Christian Rodriguez

Dissertations and Theses

No abstract provided.

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Complexity Of Minimum Corridor Guarding Problems, Ning Xu Jan 2011

Complexity Of Minimum Corridor Guarding Problems, Ning Xu

Dissertations and Theses

"In this paper, the complexity of minimum corridor guarding problems is discussed. These problem can be described as: given a connected orthogo-nal arrangement of vertical and horizontal line segments and a guard with unlimited visibility along a line segment, find a tree or a closed tour with minimum total length along edges of the arrangement, such that if the guard runs on the tree or on the closed tour, all line segments are visited by the guard. These problems are proved to be NP-complete. Keywords: computational complexity, computational geometry, corridor guarding, NP-complete"

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Parallel Computing With Improved Techniques For Monte Carlo Simulation In Var, Ping Hung Wu Jan 2011

Parallel Computing With Improved Techniques For Monte Carlo Simulation In Var, Ping Hung Wu

Dissertations and Theses

"Value at Risk ( VaR ) is a widely used tool for the assessment of one’s investments. VaR is used to evaluate the risk of loss on a financial portfolio. This metric can be computed in several ways. In the historical approach, past trends of the appropriate combination of stocks is used to estimate current portfolio fluctuations. The variance – covariance method, meanwhile, seeks to discover relationships in price fluctuations for one’s stocks. Finally, Monte Carlo simulation capitalizes upon the stochastic nature of stock prices to predict future value. This latter approach, however, relies heavily on the multiplication of vectors …

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Strengthening Virginia’S Wetlands Management Programs, Center For Coastal Resources Management, Virginia Institute Of Marine Science, Molly Mitchell, Marcia Berman, Harry Berquist, Julie Bradshaw, Karen Duhring, Sharon Killeen, Carl Hershner Jan 2011

Strengthening Virginia’S Wetlands Management Programs, Center For Coastal Resources Management, Virginia Institute Of Marine Science, Molly Mitchell, Marcia Berman, Harry Berquist, Julie Bradshaw, Karen Duhring, Sharon Killeen, Carl Hershner

Reports

No abstract provided.

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Sensitivity Of Planetary Boundary Layer Atmosphere To Historical And Future Changes Of Land Use/Land Cover, Vegetation Fraction, And Soil Moisture In Western Kentucky, Usa, Rezaul Mahmood Jan 2011

Sensitivity Of Planetary Boundary Layer Atmosphere To Historical And Future Changes Of Land Use/Land Cover, Vegetation Fraction, And Soil Moisture In Western Kentucky, Usa, Rezaul Mahmood

School of Natural Resources: Faculty Publications

No abstract provided.

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Impacts Of Irrigation On Dry Season Precipitation In India, Rezaul Mahmood Jan 2011

Impacts Of Irrigation On Dry Season Precipitation In India, Rezaul Mahmood

School of Natural Resources: Faculty Publications

No abstract provided.

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Heat Flux Measurements And Modeling Of Malodorous Compounds Above An Anaerobic Swine Lagoon, Rezaul Mahmood Jan 2011

Heat Flux Measurements And Modeling Of Malodorous Compounds Above An Anaerobic Swine Lagoon, Rezaul Mahmood

School of Natural Resources: Faculty Publications

No abstract provided.

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Comparing Optical Sensing Using Slab Waveguides And Total Internal Reflection Ellipsometry, Sofyan A. Taya, Taher M. El-Agez Jan 2011

Comparing Optical Sensing Using Slab Waveguides And Total Internal Reflection Ellipsometry, Sofyan A. Taya, Taher M. El-Agez

Turkish Journal of Physics

The sensitivity of the effective refractive index of slab waveguide sensors to variations in the refractive index of the cladding is compared to that of the ellipsometric parameters. The changes of the effective refractive index of a waveguide and the ellipsometric parameter \Delta , due to the index change of the cladding, were derived and plotted as a function of the guiding layer thickness and with the index of the cladding. It is found that these changes almost have the same overall feature but the ellipsometric parameters showed considerable higher sensitivity than the effective index of the conventional waveguide optical …

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Nuclear Structure Of Even-Even Ge Isotopes By Means Of Interacting Boson Models, Abdul R. H. Subber Jan 2011

Nuclear Structure Of Even-Even Ge Isotopes By Means Of Interacting Boson Models, Abdul R. H. Subber

Turkish Journal of Physics

Interacting Boson Models IBM-1and IBM-2, have been used to calculate energy levels and nuclear properties of the even-even Ge isotopes from A = 64 to A = 80. Energy levels of the low lying states of these nuclei were produced, the electric quadruple reduced transition probabilities B(E2) were calculated as well. Mixing ratios \delta (E2/M1) for transitions with \Delta I=0, I \ne 0 were calculated. All the results are compared with available experimental data and other IBM versions and calculations. Satisfactory agreements were produced.

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Analytical Expression For Mode-Coherence Coefficient Of A Uniformly-Distributed Wave Propagating In Different Homogeneous Media, Noor Ezzulddin Naji Jan 2011

Analytical Expression For Mode-Coherence Coefficient Of A Uniformly-Distributed Wave Propagating In Different Homogeneous Media, Noor Ezzulddin Naji

Turkish Journal of Physics

Presented is a derivation of an analytical expression for the mode-coherence coefficients of uniform-distributed wave propagating within different homogeneous media-as in the case of hyperbolic Gaussian beams-and a simple method involving the superposition of two such beams is proposed. The results obtained from this work are very applicable to study and analysis of Hermite-Gaussian beam propagation, especially in the problems of radiation-matter interaction, and laser beam propagation such as employed in free-space and fiber optical communications.

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Study Of Differential Cross Section Using Different Bound State Potentials, Ass'ad I. Ass'ad Jan 2011

Study Of Differential Cross Section Using Different Bound State Potentials, Ass'ad I. Ass'ad

Turkish Journal of Physics

In this study, heavy ion reactions of ^6Li + (^{58}Ni, ^{28}Si, ^{12}C) and ^7Li + ^{12}C are studied using different bound state potentials, within the framework of the Distorted Wave Bourn Approximation (DWBA) calculations. Woods-Saxon potential is expressed as the optical potential in the initial and final channels together with a Coulomb potential. The calculations of the angular distributions are found to be in a good agreement with the experimental data. The extracted spectroscopic factors are reasonable.

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Resonant Transfer Excitation Followed By X-Ray For Boron-Like Ions, Hassan Ramadan Jan 2011

Resonant Transfer Excitation Followed By X-Ray For Boron-Like Ions, Hassan Ramadan

Turkish Journal of Physics

Theoretical cross sections for resonant transfer excitation followed by x-ray emission (RTEX) are calculated for the collisions of some ions in the series of the Boron-like ions with H_2 as a target. The calculations have been done for C II, N III, O IV, F V, Ar XIV and Fe XXII ions by folding their dielectronic recombination (DR) cross sections over the momentum distribution (Compton profile) of H_2 target gas. Calculations have been performed from both ground and metastable initial states, in LS - coupling, allowing for \triangle n = 0 excitations. In the present work, the RTEX cross sections …

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2n-Dimensional At Fujii Model Instanton-Like Solutions And Coupling Constant's Role Between Instantons With Higher Derivatives, Mehmet Keçeci̇ Jan 2011

2n-Dimensional At Fujii Model Instanton-Like Solutions And Coupling Constant's Role Between Instantons With Higher Derivatives, Mehmet Keçeci̇

Turkish Journal of Physics

An instanton-like solution is considered for a class of two-dimensional conformal model with Liouville term. The model expressed here is a new higher-dimensional model with scalar-spinor interaction on even-dimensional spaces, and is a generalization of the even-dimensional Fujii model. A recurrence relation for the Fujii model and coupling constant's indices between relations with interaction constant is extracted. The behavior of Gürsey, Akdeniz-Smailagi' c and Fujii coupling constants in 4-dimensional conformal models are examined.

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Metals And Metal Oxides Particles Produced By Pulsed Laser Ablation Under High Vacuum, Khurram Siraj, Yasir Sohail, Aasma Tabassum Jan 2011

Metals And Metal Oxides Particles Produced By Pulsed Laser Ablation Under High Vacuum, Khurram Siraj, Yasir Sohail, Aasma Tabassum

Turkish Journal of Physics

A pulsed KrF Excimer laser (248 nm, 15 mJ) was utilized to synthesize different particles on (111) Si substrate under vacuum \sim 10^{-6} torr using Aluminum (Al), Platinum (Pt), Tungsten (W), Molybdenum (Mo), Cadmium Oxide (CdO), and Yttrium Oxide (Y_2O_3) targets. Scanning electron microscope (SEM) was used to study particle size distribution on silicon substrate. The size of individual metal particles was found to be ranging from 71 nm to 2 \mu m whereas metal oxides particles were found in the range of 71 nm to 1.1 \mu m. The particles below 100 nm are formed by gas phase condensation …

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Electronic Structure Of The Ge And Se Vacancies In Gese Layered Semiconductor, Zakir Jahangirli Jan 2011

Electronic Structure Of The Ge And Se Vacancies In Gese Layered Semiconductor, Zakir Jahangirli

Turkish Journal of Physics

We report the results of a theoretical investigation of electronic properties of ideal cation and anion vacancies in GeSe. The calculations have been performed using self-consistent Green's function method. The bulk electronic structure is described by a tight-binding Hamiltonian in the bases sets of Linear Combinations of Atomic Orbitals (LCAO). The Green's function of the perfect crystal evaluated using an eigenfunction expansion employing wave functions and band structures obtained from a self-consistent, pseudopotential, local-density-functional calculation. The defect potential is calculated using occupied electron states of the perturbed system. Results are obtained in terms of vacancy bound states, vacancy resonances, and …

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Resonance Phenomena And Time Asymmetric Quantum Mechanics, Arno Rudolf Bohm, Fati̇h Erman, Haydar Uncu Jan 2011

Resonance Phenomena And Time Asymmetric Quantum Mechanics, Arno Rudolf Bohm, Fati̇h Erman, Haydar Uncu

Turkish Journal of Physics

This article is a review of time asymmetric quantum theory and its consequences applied to the resonance and decay phenomena. We first give some phenomenological results about resonances and decaying states to support the popular idea that resonances characterized by a width \Gamma and decaying states characterized by a lifetime \tau are different appearances of the same physical entity. Based on Weisskopf-Wigner (WW) methods, one obtains approximately \frac{\hbar}{\tau}\approx \Gamma. However, using standard axioms of quantum physics it is not possible to establish a rigorous theory to which the various WW methods can be considered as approximations. In standard quantum theory, …

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Structural Studies Of Complex Compounds Of 6,6'-Diacetyl-2,2'-Bipyridine Dioxime With Copper(I/Ii), Platinum(Ii), And Palladium(Ii) Metal Ions, Abdurrahman Şengül, Hakan Ağaç, Burak Çoban, Erol Eroğlu Jan 2011

Structural Studies Of Complex Compounds Of 6,6'-Diacetyl-2,2'-Bipyridine Dioxime With Copper(I/Ii), Platinum(Ii), And Palladium(Ii) Metal Ions, Abdurrahman Şengül, Hakan Ağaç, Burak Çoban, Erol Eroğlu

Turkish Journal of Chemistry

The tetradentate ligand 6,6'-diacetyl-2,2'-bipyridine dioxime (L) was obtained in high yield by the condensation reaction of 6,6'-diacetyl-2,2'-bipyridine with hydroxyl amine in alkaline solution. Density functional calculations and 3D modeling of the structure at the B3LYP/6-31G(d) level of theory for L revealed that the energy difference between the global trans conformer (trans-L), which possesses the C_{2h} point group, and the distorted cis conformer (cis-L) was 5.214 kcal/mol. Synthesis and characterization of the metal complexes with Cu(I), Cu(II), Pt(II), and Pd(II) metal ions were reported. L acted as a N_4-donor ligand to coordinate to the metal centers via N atoms of the …

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Antimicrobial Activity And Volatile Constituents Of The Flower, Leaf, And Stem Of Paeonia Daurica Grown In Turkey, Gonca Tosun, Nuran Kahri̇man, Canan Albay, Şengül Alpay Karaoğlu, Nuretti̇n Yayli Jan 2011

Antimicrobial Activity And Volatile Constituents Of The Flower, Leaf, And Stem Of Paeonia Daurica Grown In Turkey, Gonca Tosun, Nuran Kahri̇man, Canan Albay, Şengül Alpay Karaoğlu, Nuretti̇n Yayli

Turkish Journal of Chemistry

The volatile constituents of the essential oils from the flower, leaf, and stem of Paeonia daurica Andrews were analyzed by GC and GC-MS. A total of 74 compounds were identified, constituting over 95.0%, 80.8%, and 98.2% of the oil composition of the flower, leaf, and stem of P. daurica, respectively. Aldehydes were shown to be the main group of constituents of the flower and stem parts, at 39.1% and 79.8%, respectively. However, the major group in the leaf oil was found to be oxygenated monoterpenes (43.5%). Salicylaldehyde (20.7% and 79.5%) was the major component of the flower and stem oils …

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Null Mannheim Curves In The Minkowski 3-Space E_1^3, Handan Özteki̇n, Mahmut Ergüt Jan 2011

Null Mannheim Curves In The Minkowski 3-Space E_1^3, Handan Özteki̇n, Mahmut Ergüt

Turkish Journal of Mathematics

In this study, we give the definition of null Mannheim curve with timelike or spacelike Mannheim partner curve in the Minkowski 3-space E _1^3. We get the necessary and sufficient conditions for the null Mannheim curves. Then we investigate the null and timelike or spacelike generalized helix as the null Mannheim curve and timelike or spacelike Mannheim partner curve, respectively.

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