Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons™

Open Access. Powered by Scholars. Published by Universities.®

2003

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 3451 - 3480 of 3876

Full-Text Articles in Physical Sciences and Mathematics

Quantitative Analysis Of L-Hyoscyamine In Hyoscyamus Reticulatus L. By Gc-Ms, Murat Kartal, Semra Kurucu, Levent Altun, Ti̇murhan Ceyhan, Esi̇n Sayar, Şemsetti̇n Cevheroğlu, Yalcin Yetki̇n Jan 2003

Quantitative Analysis Of L-Hyoscyamine In Hyoscyamus Reticulatus L. By Gc-Ms, Murat Kartal, Semra Kurucu, Levent Altun, Ti̇murhan Ceyhan, Esi̇n Sayar, Şemsetti̇n Cevheroğlu, Yalcin Yetki̇n

Turkish Journal of Chemistry

The hyoscyamine content of leaves and root samples of Hyoscyamus reticulatus} L. from Bulanık, Muş in east Anatolia, Turkey, was determined by capillary GC-MS to be 0.036 \pm 0.004% in the leaves and 0.056 \pm 0.011\% in the roots as the predominant compound. Sopolamine was only detected in trace amounts. These findings are in accordance with reports on hyoscyamine content in Hyoscyamus} species. The limit of detection was 3.125 \mu g/mL and the limit of quantification was 6.25 \mu g/mL for hyoscyamine. This method has been shown to be linear and sensitive.

Go to article

Kinetics And Mechanism Of Oxidation Of L-Isoleucine And L-Ornithine Hydrochloride By Sodium N-Bromobenzenesulphonamide In Perchloric Acid Medium, Hemmige S. Yathirajan, Chapuradoddi R. Raju, Kikkeri N. Mohana, Sheena Shashikanth, Padmarajaiah Nagaraja Jan 2003

Kinetics And Mechanism Of Oxidation Of L-Isoleucine And L-Ornithine Hydrochloride By Sodium N-Bromobenzenesulphonamide In Perchloric Acid Medium, Hemmige S. Yathirajan, Chapuradoddi R. Raju, Kikkeri N. Mohana, Sheena Shashikanth, Padmarajaiah Nagaraja

Turkish Journal of Chemistry

Kinetic studies of the oxidation of L-isoleucine (ISL) and L-ornithine hydrochloride (ORH) by sodium N-bromobenzenesulphonamide (bromamine-B or BAB) were studied in aqueous perchloric acid medium. The rate shows first-order dependence on both [BAB]_0 and [amino acid]_0 and inverse first-order dependence on [H^+] for ISL and first-order dependence on [H^+] for ORH. The rate of reaction decreased with decreases in the dielectric constant of the medium. The addition of benzenesulphonamide (BSA), which is one of the reaction products, had no significant effect on the reaction rate. The rate remained unchanged with the variation in the ionic strength of the medium for …

Go to article

Effects Of Sucrose Concentration During Citric Acid Accumulation By Aspergillus Niger, Ayşegül Peksel, Cristian P. Kubicek Jan 2003

Effects Of Sucrose Concentration During Citric Acid Accumulation By Aspergillus Niger, Ayşegül Peksel, Cristian P. Kubicek

Turkish Journal of Chemistry

A number of regulatory mechanisms are involved in increasing citric acid production under certain conditions. The accumulation of citric acid takes place under the high concentration of carbon sources. The effect of sucrose as a carbon source on the accumulation of citric acid and tyrosine phosphorylated proteins during high glycolytic conditions was investigated using Aspergillus niger ATCC 11414. When mycelia are treated by different sucrose concentrations, a protein of \sim 27 kDa becomes tyrosine phosphorylated. This tyrosine phosphorylation takes place in response to signal transduction from the extracellular milieu. A possible role of this \sim 27 kDa protein in signal …

Go to article

Cerimetric Determination Of Propranolol In Bulk Drug Form And In Tablets, Kanakapura Basavaiah, Umakanthappa Chandrashekar, H. Chandrashekar Prameela Jan 2003

Cerimetric Determination Of Propranolol In Bulk Drug Form And In Tablets, Kanakapura Basavaiah, Umakanthappa Chandrashekar, H. Chandrashekar Prameela

Turkish Journal of Chemistry

Two simple, accurate and precise methods are described for the determination of propranolol hydrochloride with cerium(IV) sulphate. The titrimetric method is based on the oxidation of the drug by a known excess amount of cerium(IV) sulphate and back titration of the unconsumed oxidant with ammonium ferrous sulphate. In the spectrophotometric method, the unreacted cerium(IV) sulphate is treated with iron(II) sulphate, and the iron(III) sulphate produced is complexed with thiocyanate and measured at 480 nm, thereby permitting the determination of the amount of unreacted cerium(IV) sulphate. In both procedures, the amount of the reacted oxidant corresponds to the drug content. Different …

Go to article

The In Vitro Effects Of Dexamethasone On Sheep Lens Glucose-6-Phosphate Dehydrogenase, Şükrü Beydemi̇r, Destan Ni̇l Kulaçoğlu, Mehmet Çi̇ftçi̇, Ömer İrfan Küfrevi̇oğlu Jan 2003

The In Vitro Effects Of Dexamethasone On Sheep Lens Glucose-6-Phosphate Dehydrogenase, Şükrü Beydemi̇r, Destan Ni̇l Kulaçoğlu, Mehmet Çi̇ftçi̇, Ömer İrfan Küfrevi̇oğlu

Turkish Journal of Chemistry

Glucose-6-phosphate dehydrogenase (G6PD) enzyme was purified from sheep lenses, and the in vitro effects of dexamethasone on the enzyme's activity were investigated. Sheep lens glucose-6-phosphate dehydrogenase was purified 10,000-fold by using ammonium sulphate fractionation and 2',5'-ADP-Sepharose 4B affinity gel chromatography for a yield of 83.8\% and a specific activity of 7.6 EU/mg protein. Enzyme activity was determined by Beutler's method. Dexamethasone strongly inhibited the enzyme under in vitro conditions. The I_{50} value of the dexamethasone was 3.05 mM.

Go to article

Silver Removal From Aqueous Solution By Adsorption On Concrete Particles, Shakila Begum Jan 2003

Silver Removal From Aqueous Solution By Adsorption On Concrete Particles, Shakila Begum

Turkish Journal of Chemistry

The ability of concrete to remove silver from its aqueous solutions was studied. Silver removal is favored by low concentration and high pH at room temperature. The intrinsic acidity constants, average pK_{a1}^{int} and average pK_{a2}^{int} were determined. The calculated pH_{PZC} (5.4) is in agreement with the pH_{PZC} values determined from zeta potential measurements, indicating that the concrete particulate behaves amphoterically. The total acidity capacity for the negative and positive surface was 0.5 \muC/cm^2. A surface complex formation model (SCFM) was used to describe the adsorption of silver onto concrete particles. In general the equilibrium constants, the pK_S^i values, decrease as …

Go to article

Adsorption Of Arsenate And Chromate From Waters On Hydrophobized Zeolitic Media, Eva Chmielewska Jan 2003

Adsorption Of Arsenate And Chromate From Waters On Hydrophobized Zeolitic Media, Eva Chmielewska

Turkish Journal of Chemistry

A laboratory setup was used to examine the uptake of chromate and arsenate from aqueous solutions by octadecylammonium acetate [ODA]-modified inland clinoptilolite. In trials, a natural variety of montmorillonite was compared to organic, i.e. surfactant loaded clinoptilolite. and some inorganically substituted (Ag, Pb) monoforms. The arrangement of the surface-attached ODA chains was the important factor for differences in the adsorption states of the guest species (oxyanions). A novel nano-structure inorganic-organic composite was prepared and was characterized by SEM, thermogravimetry, HR TEM, UV-VIS diffuse reflectance and powder XRD spectral analytical methods. Finally, the adsorption isotherms of the studied system were expressed. …

Go to article

Solid Phase Extraction Of Copper(Ii) By Modified Octadecyl Silica Membrane Disks With 3-{2-[2-(2-Hydroxyimino-1-Methyl-Propylideneamino)- Ethylamino]-Ethyl-Imino}-Butan-2-One~Oxime, Ömer Dalman, Serdar Karaböcek, Ahmet Demi̇rak, Mehmet Tüfekçi̇ Jan 2003

Solid Phase Extraction Of Copper(Ii) By Modified Octadecyl Silica Membrane Disks With 3-{2-[2-(2-Hydroxyimino-1-Methyl-Propylideneamino)- Ethylamino]-Ethyl-Imino}-Butan-2-One~Oxime, Ömer Dalman, Serdar Karaböcek, Ahmet Demi̇rak, Mehmet Tüfekçi̇

Turkish Journal of Chemistry

A simple, selective and rapid method for determining trace amounts of copper(II) ions in various types of water samples using atomic absorption spectrophotometry was investigated. Copper(II) ions from water samples were preconcentrated by solid phase extraction using octadecyl silica membrane disks modified with 3-{2-[2-(2-hydroxyimino- 1-methyl-propylideneamino)-ethylamino]-ethyl-imino}-butan-2-one oxime, (H_{2}mdo). The experimental conditions were optimized by changing several parameters such as volume of eluting solvent, the effect of pH, eluent flow rates, the amount of H_2mdo, breakthrough the volume, limit of detection and maximum capacity of the disks for Cu^{2+} recovery. The method was applied to the recovery of Cu(II) ions from seven …

Go to article

Synthesis, Characterization And Biological Applications Of Organotin(Iv) Derivatives Of 2-(2-Fluoro-4-Biphenyl)Propanoic Acid, Sohail Mahmood, Saqib Ali, Moazzam Hussain Bhatti, Mohammad Mazhar, Rashid Iqbal, Khalid Mohammed Khan, Ghulam Mustafa Maharvi Jan 2003

Synthesis, Characterization And Biological Applications Of Organotin(Iv) Derivatives Of 2-(2-Fluoro-4-Biphenyl)Propanoic Acid, Sohail Mahmood, Saqib Ali, Moazzam Hussain Bhatti, Mohammad Mazhar, Rashid Iqbal, Khalid Mohammed Khan, Ghulam Mustafa Maharvi

Turkish Journal of Chemistry

A series of organotin(IV) derivatives with the general formula R_{4 - n}SnL_{n} (where n = 1 or 2, R = Me, Et, n-Bu, Ph and L = 2-(2-fluoro-4-biphenyl)propanoate) have been synthesized and characterized by infrared, multinuclear NMR (^{1}H, ^{13}C, ^{119}Sn), ^{119m}Sn Mössbauer spectroscopy and mass spectrometry. Screening tests of these compounds showed that they are highly active against various bacteria and fungi.

Go to article

Potentiometric And Spectroscopic Studies With Chromium(Iii) Complexes Of Hydroxysalicylic Acid Derivatives In Aqueous Solution, M. Suat Aksoy, Ulvi̇ye Özer Jan 2003

Potentiometric And Spectroscopic Studies With Chromium(Iii) Complexes Of Hydroxysalicylic Acid Derivatives In Aqueous Solution, M. Suat Aksoy, Ulvi̇ye Özer

Turkish Journal of Chemistry

The stoichiometries and stability constants of the chromium(III) complexes of hydroxysalicylic acid ligands (2,x-dihydroxy benzoic acids; 2,x-DHBA, x = 4-6)(H_3L) were determined in aqueous solution by potentiometry and spectroscopy at 25 °C and at an ionic strength of 0.1 mol L^- (KNO_3). The existence of Cr(HL)^+ type complex was verified. The stability constants of coordination species that exist in Cr(III):2,x-DHBA systems were defined. In the acidic medium the major coordination species involve salicylate type coordination. The formation of monohydroxo complexes was observed at higher pH values.

Go to article

Investigation Of The Surface Acidity Of A Bentonite Modified By Acid Activation And Thermal Treatment, Tülay Alemdaroğlu, Gülcan Akkuş, Müşerref Onal, Yüksel Sarikaya Jan 2003

Investigation Of The Surface Acidity Of A Bentonite Modified By Acid Activation And Thermal Treatment, Tülay Alemdaroğlu, Gülcan Akkuş, Müşerref Onal, Yüksel Sarikaya

Turkish Journal of Chemistry

The adsorption of n-butylamine from its solution in cyclohexane on acid-activated and thermally treated Kütahya/Turkey bentonite (KB) samples was followed using a UV-VIS spectrophotometric method. The experimental data were evaluated by the Langmuir adsorption equation and the total number of surface acid centers (n_{m/mol} g^{-1}) was determined. The variation in n_m values as a function of the mass percent of H_2SO_4 used in activation (10%-70%) and its correlation with variations in surface area (A) and pore volume (V) as a function of the mass percent of H_2SO_4 were investigated for acid- activated KB samples. The variation in n_m values as …

Go to article

Isolation And Characterization Of A Smectite As A Micro-Mesoporous Material From A Bentonite, Müşerref Önal, Yüksel Sarikaya, Tülay Alemdaroğlu, İhsan Bozdoğan Jan 2003

Isolation And Characterization Of A Smectite As A Micro-Mesoporous Material From A Bentonite, Müşerref Önal, Yüksel Sarikaya, Tülay Alemdaroğlu, İhsan Bozdoğan

Turkish Journal of Chemistry

A procedure was assessed for obtaining an optimum amount of a micro-mesoporous material known as smectite from Reşadiye (Tokat/Turkey) bentonite. The procedure, which will permit a better economic evaluation of the Reşadiye reserves, is based on successive settlements of bentonite suspensions during various time intervals. To characterize the original bentonite, its fractions and the high purity smectite product, X-ray diffraction, differential thermal analysis, thermogravimetric analysis, scanning electron microscopy and nitrogen adsorption-desorption techniques were used. The original bentonite contained 50% by mass sodium-rich smectite (NaS) and 10% by mass NaCa-smectite (NaCaS). It also contained illite, clinoptilolite, analcime, feldspar, calcite, dolomite, quartz …

Go to article

Kinetics Of Oxidation Of Pyridylmethylsulphinylbenzimidazole By Cerium(Iv) In An Aqueous Perchloric Acid Medium, Dinesh C. Bilehal, Ravi̇raj M. Kulkarni, Sharanappa T. Nandibewoor Jan 2003

Kinetics Of Oxidation Of Pyridylmethylsulphinylbenzimidazole By Cerium(Iv) In An Aqueous Perchloric Acid Medium, Dinesh C. Bilehal, Ravi̇raj M. Kulkarni, Sharanappa T. Nandibewoor

Turkish Journal of Chemistry

The kinetics of oxidation of pyridylmethylsulphinylbenzimidazole [PMSB] by Ce(IV) in an aqueous perchloric acid medium at a constant ionic strength of 1.50 mol dm^{-3} were studied spectrophotometrically. The reaction showed first order kinetics with respect to Ce(IV) concentration and an apparent less than unit order dependence in [PMSB] and a zero order in [H^+]. The initial addition of products has no significant effect on the rate of the reaction. A possible mechanism is proposed here. The reaction constants involved in the mechanism have been computed. There is good agreement between the observed and calculated rate constants under different experimental conditions. …

Go to article

Application Of Potassium Chromate-Diphenylcarbazide In The Quantitative Determination Of Ascorbic Acid By Spectrophotometry, Meissam Noroozifar, M. Khorasani Motlagh Jan 2003

Application Of Potassium Chromate-Diphenylcarbazide In The Quantitative Determination Of Ascorbic Acid By Spectrophotometry, Meissam Noroozifar, M. Khorasani Motlagh

Turkish Journal of Chemistry

A spectrophotometric procedure for the determination of ascorbic acid in pure form and in a number of pharmaceutical preparations and real samples has been developed that offers the advantages of simplicity, accuracy, precision and sensitivity over many other methods. The method is based on the oxidation of ascorbic acid by a known excess amount of potassium chromate followed by the estimation of the unreacted amount of chromate by reactions with sym-diphenylcarbazide. The reacted oxidant corresponds to the ascorbic content. At the maximum absorption of 548 nm, Beer's law is obeyed up to 5 \mu g/mL of ascorbic acid. Statistical treatment …

Go to article

The Composition Of Fatty Acids In Hypericum Scabrum, H. Scabroides And H. Amblysepalum, Hasan Çeti̇n Özen, Mehmet Başhan Jan 2003

The Composition Of Fatty Acids In Hypericum Scabrum, H. Scabroides And H. Amblysepalum, Hasan Çeti̇n Özen, Mehmet Başhan

Turkish Journal of Chemistry

The chemical composition of the fatty acid methyl esters (FAMEs) of flowering tops of Hypericum scabrum, H. scabroides and H. amblysepalum were identified by gas chromatography. In this work 5 FAMEs for H. scabrum, 9 FAMEs for H. scabroides and 8 FAMEs for H. amblysepalum were identified. The major components were alpha-linolenic (48.60%), linoleic (32.53%) and oleic (11.45%) acids in H. scabrum. Alpha-linolenic (29.84%), palmitic (27.90%) and oleic (16.49%) acids were present in H. scabroides and alpha linolenic (41.79%) and palmitic acids (32.28%) were found in H. amblysepalum.

Go to article

Synthesis And Analgesic And Anti-Inflammatory Activity Of New Pyridazinones, Deni̇z S. Doğruer, M. Fethi̇ Şahi̇n, Esra Küpeli̇, Erdem Yeşi̇lada Jan 2003

Synthesis And Analgesic And Anti-Inflammatory Activity Of New Pyridazinones, Deni̇z S. Doğruer, M. Fethi̇ Şahi̇n, Esra Küpeli̇, Erdem Yeşi̇lada

Turkish Journal of Chemistry

A new series of 2-(6-oxo-3,5-diphenyl-6H-pyridazin-1-yl)- acetamides and 3-[6-oxo-3,5-diphenyl-6H-pyridazin-1-yl)-propanamides were synthesized and evaluated in terms of their analgesic and anti-inflammatory activities. All compounds except for 7g were more potent than aspirin in a p-benzoquinone--induced writhing test at 100 mg/kg dose. Compounds 7b, 7c and 7e had the highest anti-inflammatory activity; compound 7e was the most potent in terms of analgesic and anti-inflammatory activities and had no ulcerogenic side effects.

Go to article

Chemical Constituents Of Campanula Lactiflora, Nuretti̇n Yayli, Nuri̇ Yildirim, Asu Usta, Serpi̇l Özkurt, Vi̇ldan Akgün Jan 2003

Chemical Constituents Of Campanula Lactiflora, Nuretti̇n Yayli, Nuri̇ Yildirim, Asu Usta, Serpi̇l Özkurt, Vi̇ldan Akgün

Turkish Journal of Chemistry

A new flavonoid glycoside, 4'-O-(p-hydroxybenzoyl)-isorhamnetin-3,7- di-O-\beta-D-glucopyranoside (1), and 4 known compounds, sitosterol \beta-D-glucoside (2), bis(2-ethylhexyl) adipate (3), p-hydroxybenzoic acid (4) and ethyl docosanoate (5), were isolated for the first time from Campanula lactiflora and their structures were deduced by high field 1D and 2D NMR and (+) FAB and EI mass spectra.

Go to article

Synthesis And Evaluation Of Antimicrobial Activity Of New 3-Hydroxy-6-Methyl-4-Oxo-4h-Pyran-2- Carboxamide Derivatives, Mutlu Di̇lsi̇z Aytemi̇r, Di̇lek Demi̇r Erol, Robert Charles Hider, Meral Özalp Jan 2003

Synthesis And Evaluation Of Antimicrobial Activity Of New 3-Hydroxy-6-Methyl-4-Oxo-4h-Pyran-2- Carboxamide Derivatives, Mutlu Di̇lsi̇z Aytemi̇r, Di̇lek Demi̇r Erol, Robert Charles Hider, Meral Özalp

Turkish Journal of Chemistry

The synthesis of a range of 3-hydroxy-4-oxo-4H-pyran-2- carboxamide with antimicrobial activity is described. Amide derivatives of pyranone were synthesised using TBTU [2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate] as a coupling agent and NMM (N-methylmorpholine) as a base. Antimicrobial activities were determined as MIC values using the microdilution broth method against Staphylococcus aureus, Entrococcus faecalis, Escherichia coli and Pseudomonas aeruginosa for bacteria and Candida albicans, C. krusei and C. parapsilosis for fungi. 3-Hydroxy-6-methyl-4-oxo-4H-pyran-2-[N-(4'-methylcoumarin-7-yl) carboxamide] (8c) exhibited higher antibacterial activity against S. aureus, E. faecalis and E. coli than the other compounds. In addition, 8c was more active against C. krusei than the other synthesised compounds.

Go to article

6-O-\Alpha-L-Rhamnopyranosylcatalpol Derivative Iridoids From Verbascum Cilicicum, İ. İrem Tatli, Zeli̇ha Ş. Akdemi̇r, Erdal Bedi̇r, Ikhlas A. Khan Jan 2003

6-O-\Alpha-L-Rhamnopyranosylcatalpol Derivative Iridoids From Verbascum Cilicicum, İ. İrem Tatli, Zeli̇ha Ş. Akdemi̇r, Erdal Bedi̇r, Ikhlas A. Khan

Turkish Journal of Chemistry

From the aerial parts of Verbascum cilicicum Boiss., 6 iridoid glycosides, namely catalpol (1), verbaspinoside [= 6-O-(2'' -O-trans-cinnamoyl)-\alpha-L-rhamnopyranosylcatalpol] (2), 6-O-(3''-O-trans-cinna\-moyl)-\alpha-L-rhamnopyranosylcatalpol (3), 6-O-(4''-O-trans-cinnamoyl)-\alpha -L-rhamnopyranosylcatalpol (4), saccatoside [= 6-O-(2''-O-trans-p-coumaroyl)-\alpha-L-rhamnopyranosylcatalpol] (5), and 6-O-(3''-O-trans-p-coumaroyl)-\alpha-L-rhamnopyranosylcatalpol (6), were isolated. The structures of the compounds were elucidated by means of 1 and 2 dimensional (DQF-COSY, HMQC and HMBC) NMR techniques and LC-ESIMS.

Go to article

Plasticiser Effect On Water Vapour Permeability Properties Of Locust Bean Gum--Based Edible Films, Özgür Altan Bozdemi̇r, Mehmet Tutaş Jan 2003

Plasticiser Effect On Water Vapour Permeability Properties Of Locust Bean Gum--Based Edible Films, Özgür Altan Bozdemi̇r, Mehmet Tutaş

Turkish Journal of Chemistry

The barrier properties of edible films prepared from polysaccharide polymer (locust bean gum) and various plasticisers (glycerol, propylene glycol, sorbitol, and polyethylene glycol 200) together with hydrophobic modifiers (stearopten and beeswax) were examined. It was determined that the films containing polyethylene glycol 200 (PEG 200) and sorbitol have the lowest water vapour permeability values and the films containing glycerol have the highest WVP values. It was found that the most reasonable of the studied plasticisers was PEG 200. Polysaccharide--based edible films have higher WVP values than those of lipid-- and protein--based edible films. In order to reduce the WVP of …

Go to article

A Multi-Platform Application Suite For Enhancing South Asian Language Pedagogy, Tao Bai, Christopher K. Chung, Konstantin Läufer, Daisy Rockwell, George K. Thiruvathukal Jan 2003

A Multi-Platform Application Suite For Enhancing South Asian Language Pedagogy, Tao Bai, Christopher K. Chung, Konstantin Läufer, Daisy Rockwell, George K. Thiruvathukal

Computer Science: Faculty Publications and Other Works

This interdisciplinary project explores the potential for handheld/wireless (H/W) technology in the context of language education within and beyond the classroom. Specifically, we have designed and implemented a suite of multi-platform (desktop/laptop, handheld, and browser) applications to enhance the teaching of South Asian languages such as Hindi-Urdu. Such languages are very difficult to learn, let alone write, and H/W devices (with their handwriting/drawing capabilities) can play a significant role in overcoming the learning curve. The initial application suite includes a character/word tracer, a word splitter/joiner, a smart flashcard with audio, contextual augmented stories for reading comprehension, and a poetic metronome. …

Go to article

Scalable Implementations Of Mpi Atomicity For Concurrent Overlapping I/O, Wei-Keng Liao, Alok Choudhary, Kenin Coloma, George K. Thiruvathukal, Lee Ward, Eric Russell, Neil Pundit Jan 2003

Scalable Implementations Of Mpi Atomicity For Concurrent Overlapping I/O, Wei-Keng Liao, Alok Choudhary, Kenin Coloma, George K. Thiruvathukal, Lee Ward, Eric Russell, Neil Pundit

Computer Science: Faculty Publications and Other Works

For concurrent I/O operations, atomicity defines the results in the overlapping file regions simultaneously read/written by requesting processes. Atomicity has been well studied at the file system level, such as POSIX standard. In this paper, we investigate the problems arising from the implementation of MPI atomicity for concurrent overlapping write access and provide a few programming solutions. Since the MPI definition of atomicity differs from the POSIX one, an implementation that simply relies on the POSIX file systems does not guarantee correct MPI semantics. To have a correct implementation of atomic I/O in MPI, we examine the efficiency of three …

Go to article

Am I Too Fat? Bulimia As An Epidemic, Christopher Kribs, Beverly Gonzalez, Emilia Huerta-Sanchez, Angela Ortiz-Nieves, Terannie Vazquez-Alvarez Jan 2003

Am I Too Fat? Bulimia As An Epidemic, Christopher Kribs, Beverly Gonzalez, Emilia Huerta-Sanchez, Angela Ortiz-Nieves, Terannie Vazquez-Alvarez

Mathematics Faculty Publications

For at least the past ten years, eating disorders have had a major impact in the physical and mental health of women, particularly young women. Anorexia and bulimia nervosa are closely linked eating disorders. Anorexia often precedes bulimia. However, there are about 2 million women in college that have been exclusively bulimic. In this article, we focus on the role of college-peer pressure on the dynamics of anorexia-free bulimia. The model looks at bulimia as a progressive disease and explores the impact of intervention (treatment) at two stages of disease progression. The impact of relapse (a common occurrence among bulimics) …

Go to article

Jurisdictional Environmental Coordination, Gloucester County, Virginia, Pamela Mason, Carl Hershner Jan 2003

Jurisdictional Environmental Coordination, Gloucester County, Virginia, Pamela Mason, Carl Hershner

Reports

The ability to coordinate the management of human activities in the landscape from an environmental perspective has been a desired, yet elusive, interest. The ability to accurately value environmental functions economically has confounded this process; but conflicts are not confined to the obvious ones between economics and the environment. Even those activities within the field of environmental management are not always harmonious. A myriad of management activities administered at various levels of government results in a web of responsibilities lacking in any central coordination. Varied local, state, and federal programs administered by different agencies have missions that put them in …

Go to article

Timelike And Spacelike Ricci Collineation Vectors In String Fluid, Hüsnü Baysal, İhsan Yilmaz Jan 2003

Timelike And Spacelike Ricci Collineation Vectors In String Fluid, Hüsnü Baysal, İhsan Yilmaz

Turkish Journal of Physics

We study the consequences of the existence of timelike and spacelike Ricci collineation vectors (RCVs) for string fluid in the context of general relativity. Necessary and sufficient conditions are derived for a space-time with string fluid to admit a timelike RCV, parallel to u^a, and a spacelike RCV, parallel to n^a. In these cases, some results obtained are discussed.

Go to article

Initial Electron Beam Polarization Measurement In E-\Gamma Collisions, Gökhan Ünel Jan 2003

Initial Electron Beam Polarization Measurement In E-\Gamma Collisions, Gökhan Ünel

Turkish Journal of Physics

The future high energy e e colliders, together with the complementary \gamma \gamma option, will offer possibilities for both discovery and precision physics. The uncertainty on the initial beam polarizations contributes to the systematic errors in each case. Therefore, it is crucial to obtain the precise beam polarizations by independent measurements. The e \gamma \rightarrow \nu W process in the e \gamma mode can be used to experimentally determine the polarization of the initial e beam. This note addresses the feasibility of making such a measurement with a relative statistical error of one percent. Generator and detector level MC tools …

Go to article

Mean Multiplicity Of Quark And Gluon Jets As A Function Of Opening Angle In E^{+}E^{-} \Rightarrow B\Overline{B} G Events, Ayda Beddall Jan 2003

Mean Multiplicity Of Quark And Gluon Jets As A Function Of Opening Angle In E^{+}E^{-} \Rightarrow B\Overline{B} G Events, Ayda Beddall

Turkish Journal of Physics

A comparison of the properties of quark and gluon jets has been madeby Monte Carlo simulation of the reaction Z \rightarrow b \overline{b} g. The jet energy is held fixed for every 5 GeV between 15--30 GeV energies and the mean multiplicity of b-quark and gluon jets are obtained as function of the angle between them. It is seen that the jet properties not only depend on the jet energies but also on the angle between the jets.

Go to article

Evaluation Of The Cerc Formula Using Large-Scale Laboratory Data, Ernest R. Smith, Ping Wang, Jun Zhang Jan 2003

Evaluation Of The Cerc Formula Using Large-Scale Laboratory Data, Ernest R. Smith, Ping Wang, Jun Zhang

Geology Faculty Publications

Longshore transport experiments were conducted in a large-scale physical model to evaluate predictions of the CERC formula with measured longshore sediment transport rates. It was found that the CERC formula produced reasonable estimates if the coefficient K was calibrated and applied to waves with similar breaker type. The calibrated K values are much smaller than values that are commonly used, and there appears to be a strong dependency of transport rate on breaker type. Additional comparisons were made with the formula proposed by Kamphuis (1991). The Kamphuis equation, which includes wave period, a factor that influences breaking, gave good estimates. …

Go to article

Operation Parameters Of The Thermionic Vacuum Arc Discharge, Tamer Akan Jan 2003

Operation Parameters Of The Thermionic Vacuum Arc Discharge, Tamer Akan

Turkish Journal of Physics

The thermionic vacuum arc (TVA) discharge with evaporating anodes employing directly heated thermionic cathodes is investigated. The TVA discharge generates a pure, gas-free metal vapor plasma containing ions with a directed energy. The TVA is strongly controlled by the cathodic electron beam and there is a quite good stability of important operation parameters like the arc voltage and the arc current.

Go to article

How Round Is Round? On Accuracy In Complex Dielectric Permittivity Calculations: A Finite-Size Scaling Approach, Eni̇s Tuncer Jan 2003

How Round Is Round? On Accuracy In Complex Dielectric Permittivity Calculations: A Finite-Size Scaling Approach, Eni̇s Tuncer

Turkish Journal of Physics

Accuracy in complex dielectric permittivity calculations in binary dielectric mixtures in two-dimensions are reported by taking into account the shape of the inclusion phase. The dielectric permittivity of the mixtures were calculated using the finite element method, and the permittivities were estimated by two different procedures. The results were compared with those of analytical models based on a mean field approximation and regular arrangement of disks. We have approached the problem emphasizing the finite-size behavior in which regular polygons with n sides were assumed to mimic the disk inclusion phase. It was found that at low concentrations, < 30%, decagon-approximated circles (n = 10) cause an error of < 0.1% in the effective medium quantities compared with results obtained using analytical models.

Go to article

First Prev Next Last