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2017

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Articles 23431 - 23460 of 24667

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Synthesis, In Vitro Dna Interactions, Cytotoxicities, Antioxidative Activities, And Topoisomerase Inhibition Potentials Of Mn(Ii), Co(Ii), Ni(Ii), Cu(Ii), And Zn(Ii) Complexes With Azo-Oxime Ligands, Melek Çol Ayvaz, İbrahi̇m Turan, Bayram Dural, Seli̇m Demi̇r, Kaan Karaoğlu, Yüksel Ali̇yazicioğlu, Keri̇m Serbest Jan 2017

Synthesis, In Vitro Dna Interactions, Cytotoxicities, Antioxidative Activities, And Topoisomerase Inhibition Potentials Of Mn(Ii), Co(Ii), Ni(Ii), Cu(Ii), And Zn(Ii) Complexes With Azo-Oxime Ligands, Melek Çol Ayvaz, İbrahi̇m Turan, Bayram Dural, Seli̇m Demi̇r, Kaan Karaoğlu, Yüksel Ali̇yazicioğlu, Keri̇m Serbest

Turkish Journal of Chemistry

Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) transition metal complexes of 2-hydroxy-5-[(E)-(4-phenyl) diazenyl] benzaldehyde oxime and 2-hydroxy-5-[(E)-(4-nitrophenyl) diazenyl] benzaldehyde oxime ligands were synthesized and characterized through NMR, IR, ESI mass, and UV analysis. DNA binding abilities of the complexes were revealed using a UV-Vis spectrophotometer with the absorption titration and competitive binding techniques. Hydrolytic and oxidative DNA cleavage activities under different conditions were also proved. Topoisomerase I inhibition efficiencies and in vitro free radical scavenging activities of all complexes were examined. Finally, the selective cytotoxic potentials of all complexes were evaluated in human colon cancer, normal colon, and fibroblast cell lines …

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Removal Of Pb(Ii) And Cd(Ii) From Aqueous Solution Using Alkaline-Modified Pumice Stone Powder (Psp): Equilibrium, Kinetic, And Thermodynamic Studies, Vivian Jonasi, Kaina Matina, Upenyu Guyo Jan 2017

Removal Of Pb(Ii) And Cd(Ii) From Aqueous Solution Using Alkaline-Modified Pumice Stone Powder (Psp): Equilibrium, Kinetic, And Thermodynamic Studies, Vivian Jonasi, Kaina Matina, Upenyu Guyo

Turkish Journal of Chemistry

Adsorption processes of Cd(II) and Pb(II) from aqueous solutions onto pumice stone powder (PSP) were investigated in batch mode. The influences of solution pH, contact time, adsorbent dosage, initial metal (M) concentration, and temperature on adsorption process were investigated. The kinetic and isotherm data were analysed using different model equations. The adsorption process was consistent with the Langmuir model for both metal ions with high R$^{2}$ and low $\chi^{2}$ values for both Pb(II) and Cd(II). The maximum monolayer adsorption capacities were 28.09 and 27.17 mg g$^{-1}$ for Pb(II) and for Cd(II), respectively. The pseudo-second order kinetic model explained the kinetic …

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Adsorption Of Cu(Ii) On Three Adsorbents, Fe$_{3}$O$_{4}$/Ni/Ni$_{X}$B Nanocomposite, Carob (\Textit{Ceratonia Siliqua}), And Grape Seeds: A Comparative Study, Tüli̇n Deni̇z Çi̇ftçi̇ Jan 2017

Adsorption Of Cu(Ii) On Three Adsorbents, Fe$_{3}$O$_{4}$/Ni/Ni$_{X}$B Nanocomposite, Carob (\Textit{Ceratonia Siliqua}), And Grape Seeds: A Comparative Study, Tüli̇n Deni̇z Çi̇ftçi̇

Turkish Journal of Chemistry

A novel adsorbent Fe$_{3}$O$_{4}$/Ni/Ni$_{x}$B nanocomposite was synthesized and used for the adsorption of copper. Moreover, natural adsorbents carob and grape seeds were used for this purpose. The surfaces and the elemental compositions of the adsorbents were characterized by SEM-EDX. The zero point charges of pH of Fe$_{3}$O$_{4}$/Ni/Ni$_{x}$B nanocomposite, carob, and grape seeds were found as 8.4, 6.0, and 5.6, respectively. The Langmuir, Freundlich, and Dubinin--Radushkevich isotherm models were used for the identification of the mechanism of the adsorption. The adsorptions of Cu(II) on the three adsorbents were well fitted to the Langmuir isotherm. The maximum adsorption capacities obtained from the …

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Nanocomposite Copper Metal As An Efficient Heterogeneous Catalyst In Click Synthesis Of 1,2,3-Triazoles In Aqueous Media, Vajihe Nejadshafiee, Hossein Naeimi Jan 2017

Nanocomposite Copper Metal As An Efficient Heterogeneous Catalyst In Click Synthesis Of 1,2,3-Triazoles In Aqueous Media, Vajihe Nejadshafiee, Hossein Naeimi

Turkish Journal of Chemistry

Copper/periodic mesoporous organosilica (Cu/PMO) nanocomposites provided a highly active, reusable, globular, solid-phase catalyst for click chemistry. The reaction proceeds by mixing organohalides, sodium azide, alkyne, and the catalyst in an aqueous medium to afford the desired products. The cost efficiency and recyclability of the catalyst up to six runs without appreciable loss of activity and high yields of products make this procedure greener.

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The Multiple Effects Of Organoclay And Solvent Evaporation On Hydrophobicity Of Composite Surfaces, Haci Hasan Yolcu, Ahmet Gürses, Rabah Boukherroub Jan 2017

The Multiple Effects Of Organoclay And Solvent Evaporation On Hydrophobicity Of Composite Surfaces, Haci Hasan Yolcu, Ahmet Gürses, Rabah Boukherroub

Turkish Journal of Chemistry

A superhydrophobic high-density polyethylene (HDPE)/organoclay composite material with a water-static contact angle of $\sim $162$^{\circ}$ and low hysteresis (7$^{\circ})$ was prepared by a simple solution-intercalation technique. This one-step method consists of the insertion of organoclay, produced through cation exchange with cetyltrimethylammonium bromide (CTAB), in the polymer matrix at 120 $^{\circ}$C in xylene. In this process, evaporation of the solvent and organoclay amount are key factors for the achievement of superhydrophobicity. We characterized composite material with X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and contact angle measurements. The characterizations showed that the organoclay provides a place for …

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Cyclic Voltammetry Behavior Of Tamoxifen In Different Electrolytes, Electrochemical Characterization, And Its Measurement By Differential Pulse Anodic Voltammetry, Zeinab Deris Falahieh, Mehdi Jalali, Mohammad Alimoradi Jan 2017

Cyclic Voltammetry Behavior Of Tamoxifen In Different Electrolytes, Electrochemical Characterization, And Its Measurement By Differential Pulse Anodic Voltammetry, Zeinab Deris Falahieh, Mehdi Jalali, Mohammad Alimoradi

Turkish Journal of Chemistry

Cyclic voltammetry (CV) was performed on tamoxifen (tam) using different electrodes and in various acidic electrolytes containing 10% v v$^{-1}$ methanol (MeOH). Tam oxidation was found to be most favorable using 0.1 mol L$^{-1}$ H$_{2}$SO$_{4}$. To investigate the mechanism, we performed chronoamperometry, CV at different scan rates, differential pulse anodic voltammetry (DPAV), and electrochemical impedance spectroscopy on tam-covered glassy carbon electrodes (GCEs). The electrode area, diffusion coefficient, and surface concentration ($\Gamma )$ of tam were calculated to be 0.062 cm$^{2}$, 3.65 $\times $ 10$^{-6}$ cm$^{2}$ s$^{-1}$, and 3.2 $\times $ 10$^{-10}$ mol cm$^{-2}$ respectively. Then the effects of different parameters …

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Methanolysis Of Jatropha Curcas Oil Using K$_{2}$Co$_{3}$/Cao As A Solid Base Catalyst, Gajanan Sahu, Sujan Saha, Sudipta Datta, Prakash Chavan, Satyanarayan Naik Jan 2017

Methanolysis Of Jatropha Curcas Oil Using K$_{2}$Co$_{3}$/Cao As A Solid Base Catalyst, Gajanan Sahu, Sujan Saha, Sudipta Datta, Prakash Chavan, Satyanarayan Naik

Turkish Journal of Chemistry

Biodiesel, fatty acid methyl ester produced by the transesterification of vegetable oil with methanol, is a promising alternative to petroleum-based diesel fuel. In the present study, the methanolysis of high free fatty acid (FFA) $Jatropha$ $curcas$ oil in a transesterification reaction using K$_{2}$CO$_{3}$/CaO solid base catalyst was studied. The various reaction parameters in the transesterification reaction were also discussed. The catalyst was characterized by means of Fourier transform infrared, X-ray diffraction, temperature programmed desorption of CO$_{2}$, scanning electron microscopy, particle size analyzer, true density, and surface area analyzer. The optimum conversion of jatropha oil was 92% when the transesterification reaction …

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Synthesis Of Novel 5-Substituted Phenyl-3-(P-Isopropylphenyl)-1-Phenylformazan And Their Biological Activities, Ayşe Şahi̇n Yağlioğlu, Hülya Şenöz Jan 2017

Synthesis Of Novel 5-Substituted Phenyl-3-(P-Isopropylphenyl)-1-Phenylformazan And Their Biological Activities, Ayşe Şahi̇n Yağlioğlu, Hülya Şenöz

Turkish Journal of Chemistry

Novel 1-substituted 3-(p-isopropylphenyl)-5-phenylformazans (3a--g) were synthesized and characterized by elemental analysis, $^{1}$H NMR, and FT-IR techniques and UV-visible spectroscopy. Antiproliferative activities of 3a--g against HeLa and C6 cells were determined using the BrdU cell proliferation ELISA assay. 5-Florouracil was used as the positive control. The effects of substituents (--H, --CH$_{3}$, and --I) and their positions ($ortho$, $meta$, and $para$) on the antiproliferative activities were evaluated. The results of the assay indicate that I substituent exhibited higher activity against the cells at the $meta$ and $para$ positions than --CH$_{3}$ and --H substituents. 3a--g exhibited both high antiproliferative activities against C6 cells …

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Separation And Recovery Of Gallium(Iii) Ions From Aqueous Phase By Liquid--Liquid Extraction Using A Novel Extractant, Cyphos Il 101, Sumitra Nayak, Niharbala Devi Jan 2017

Separation And Recovery Of Gallium(Iii) Ions From Aqueous Phase By Liquid--Liquid Extraction Using A Novel Extractant, Cyphos Il 101, Sumitra Nayak, Niharbala Devi

Turkish Journal of Chemistry

The present study describes the extraction behavior of gallium(III) using a novel ionic liquid trihexyl(tetradecyl) phosphonium chloride (Cyphos IL 101) diluted with kerosene from acidic chloride medium. The extraction of gallium was found to depend on the hydrochloric acid concentration and quantitative extraction of gallium took place at 2.0 mol/L HCl concentration. The nature of the extracted complex in the organic phase was determined using Job's method and proposed to be [R$_{3}$R$^\prime $PGaCl$_{4}$]. The loading capacity of 5.0 $\times$ 10$^{-3}$ mol/L Cyphos IL 101 was determined to be 320.0 mg/L. Two stages of stripping were required for complete removal of …

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Impurity Profiling Of Morphine By Liquid Chromatography-Heated Electrospray Ionization Mass Spectrometry (Lc-Hesi-Ms), Ana Petkovska, Jelena Acevska, Marina Chachorovska, Gjorgji Petrusevski, Gjoshe Stefkov, Rumenka Petkovska, Aneta Dimitrovska, Sonja Ugarkovic Jan 2017

Impurity Profiling Of Morphine By Liquid Chromatography-Heated Electrospray Ionization Mass Spectrometry (Lc-Hesi-Ms), Ana Petkovska, Jelena Acevska, Marina Chachorovska, Gjorgji Petrusevski, Gjoshe Stefkov, Rumenka Petkovska, Aneta Dimitrovska, Sonja Ugarkovic

Turkish Journal of Chemistry

Separation of morphine and its impurities (related substances specified in relevant European Pharmacopoeia monographs, as well as the other naturally occurring coextracted alkaloids) was obtained within a close retention window on a reverse phase HPLC column, eluted with optimized gradient, consisting of methanol and 5 mM ammonium formate, adjusted to pH 10.2. Systematic optimization of the chromatographic conditions was carried out using design of experiments. According to their mass spectra, known and specified impurities were identified and tentative structures for unknown impurities were proposed. MS analyses were performed in positive ionization mode using heated electrospray ionization. Fragmentation patterns of the …

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Investigation Of The Photophysical And Photochemical Behavior Of Substituted Zinc Phthalocyanines And Their Water-Soluble Quaternized Derivatives, Gülsev Di̇lber, Mahmut Durmuş, Hali̇t Kanteki̇n Jan 2017

Investigation Of The Photophysical And Photochemical Behavior Of Substituted Zinc Phthalocyanines And Their Water-Soluble Quaternized Derivatives, Gülsev Di̇lber, Mahmut Durmuş, Hali̇t Kanteki̇n

Turkish Journal of Chemistry

New nonperipherally and peripherally tetrasubstituted zinc(II) phthalocyanine complexes containing 1-benzylpiperidin-4-ol groups and their quaternized derivatives are reported in this work. These complexes were characterized successfully and their photophysical and photochemical properties were studied. These properties were determined in dimethylsulfoxide for all studied complexes and in water and water $+$ Triton X-100 solutions for ionic Zn(II) phthalocyanines. All studied zinc(II) phthalocyanine complexes generated high singlet oxygen, especially in dimethylsulfoxide, and these properties make them potential photosensitizers for use in the photodynamic therapy of cancer. The effects of the position and quaternization of the substituents on the photophysical and photochemical properties were …

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Naked Eye And Smartphone Applicable Detection Of Toxic Mercury Ions Using Fluorescent Carbon Nanodots, Burcu Baç, Rükan Genç Jan 2017

Naked Eye And Smartphone Applicable Detection Of Toxic Mercury Ions Using Fluorescent Carbon Nanodots, Burcu Baç, Rükan Genç

Turkish Journal of Chemistry

Chitosan passivated carbon nanodots (C-Dots$_{CHIT})$ were synthesized from expired molasses via a simple and green thermal synthesis procedure. As-synthesized C-Dots were nitrogen-doped (NC-Dots$_{CHIT})$ by posttreatment with liquid ammonia and used as nanoprobes for fluorometric detection of mercury ions (Hg(II)$_{aq.})$. Fluorescence response of NC-Dots$_{CHIT}$ in the presence of mercury was evaluated and compared with that of the polyethylene glycol passivated C-Dots$_{PEG}$. This sensing strategy using NC-Dots$_{CHIT}$ displayed a wide linear working range from 1.25 $\mu $g/mL to 43.54 $\mu $g/mL with a detection limit of 1.41 $\mu $g/mL. The fluorescence of C-Dots$_{PEG}$ did not show any significant change upon mercury addition. …

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Adaptive Fuzzy Control Of Quadrotor, Muhammad Awais Sattar Jan 2017

Adaptive Fuzzy Control Of Quadrotor, Muhammad Awais Sattar

Theses

In this thesis, intelligent controllers are designed to control attitude for quadrotor UAV (Unmanned Aerial Vehicle).Quadrotors have a variety of applications in real time e.g. surveillance, inspection, search, rescue and reducing the human force in undesirable conditions. Quadrotors are generally unstable systems; the kinematics of quadrotor resembles the kinematics of inverted pendulum. In order to avoid the possibility of any kind of damages, the mathematical model of quadrotor should be developed and after that, the different control techniques can be implemented. This thesis presents a detailed simulation model for a Quadrotor. For the control purpose, three classical and modern control …

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Multiparty Computations In Varying Contexts, Paul Laird, Sarah Jane Delany, Pierpaolo Dondio Jan 2017

Multiparty Computations In Varying Contexts, Paul Laird, Sarah Jane Delany, Pierpaolo Dondio

Conference papers

Recent developments in the automatic transformation of protocols into Secure Multiparty Computation (SMC) interactions, and the selection of appropriate schemes for their implementation have improved usabililty of SMC. Poor performance along with data leakage or errors caused by coding mistakes and complexity had hindered SMC usability. Previous practice involved integrating the SMC code into the application being designed, and this tight integration meant the code was not reusable without modification. The progress that has been made to date towards the selection of different schemes focuses solely on the two-party paradigm in a static set-up, and does not consider changing contexts. …

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Spatiotemporal Distribution Of Eutrophication In Lake Tai As Affected By Wind, Wenhui Zhang, Qiujin Xu, Xixi Wang, Xiaozhen Hu, Cheng Wang, Yan Pang, Yanbin Hu, Yang Zhao, Xiao Zhao Jan 2017

Spatiotemporal Distribution Of Eutrophication In Lake Tai As Affected By Wind, Wenhui Zhang, Qiujin Xu, Xixi Wang, Xiaozhen Hu, Cheng Wang, Yan Pang, Yanbin Hu, Yang Zhao, Xiao Zhao

Civil & Environmental Engineering Faculty Publications

One common hypothesis is that wind can affect concentrations of nutrients (i.e., nitrogen and phosphorus) and chlorophyll-a (Chl-a) in shallow lakes. However, the tests of this hypothesis have yet to be conclusive in existing literature. The objective of this study was to use long-term data to examine how wind direction and wind speed affect the spatiotemporal variations of total nitrogen (TN), total phosphorus (TP) and Chl-a in Lake Tai, a typical shallow lake located in east China. The results indicated that the concentrations of nutrients and Chl-a tended to decrease from the northwest to the southeast of Lake Tai, with …

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Water–Soil–Vegetation Dynamic Interactions In Changing Climate, Xixi Wang, Xuefeng Chu, Tingxi Liu, Xiangju Cheng, Rich Whittecar Jan 2017

Water–Soil–Vegetation Dynamic Interactions In Changing Climate, Xixi Wang, Xuefeng Chu, Tingxi Liu, Xiangju Cheng, Rich Whittecar

Civil & Environmental Engineering Faculty Publications

Previous studies of land degradation, topsoil erosion, and hydrologic alteration typically focus on these subjects individually, missing important interrelationships among these important aspects of the Earth's system. However, an understanding of water–soil–vegetation dynamic interactions is needed to develop practical and effective solutions to sustain the globe's eco-environment and grassland agriculture, which depends on grasses, legumes, and other fodder or soil-building crops. This special issue is intended to be a platform for a discussion of the relevant scientific findings based on experimental and/or modeling studies. Its 12 peer-reviewed articles present data, novel analysis/modeling approaches, and convincing results of water–soil–vegetation interactions under …

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A New Job Shop Heuristic Algorithm For Machine Scheduling Problems, Maryam Ehsaei, Duc T. Nguyen Jan 2017

A New Job Shop Heuristic Algorithm For Machine Scheduling Problems, Maryam Ehsaei, Duc T. Nguyen

Civil & Environmental Engineering Faculty Publications

The purpose of this research is to present a straightforward and relatively efficient method for solving scheduling problems. A new heuristic algorithm, with the objective of minimizing the makespan, is developed and presented in this paper for job shop scheduling problems (JSP). This method determines jobs’ orders for each machine. The assessment is based on the combination of dispatching rules e.g. the "Shortest Processing Time" of each operation, the "Earliest Due Date" of each job, the "Least Tardiness" of the operations in each sequence and the "First come First Serve" idea. Also, unlike most of the heuristic algorithms, due date …

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Heavy Metal Distribution And Groundwater Quality Assessment For A Coastal Area On A Chinese Island, Sha Lou, Shuguang Liu, Chaomeng Dai, An Tao, Bo Tan, Gangfeng Ma, Roman Sergeeyvich Chalov, Sergey Romanovich Chalov Jan 2017

Heavy Metal Distribution And Groundwater Quality Assessment For A Coastal Area On A Chinese Island, Sha Lou, Shuguang Liu, Chaomeng Dai, An Tao, Bo Tan, Gangfeng Ma, Roman Sergeeyvich Chalov, Sergey Romanovich Chalov

Civil & Environmental Engineering Faculty Publications

Chongming Island is located in the lower Yangtze Estuary in China. Due to the Leachate from a refuse landfill and the hydrodynamics of the Yangtze Estuary, the groundwater environment is particularly complicated on Chongming Island. Field observations were carried out around the landfill disposal site. The groundwater table, temperature, pH, salinity, and dissolved oxygen were measured in the field by portable equipment, and 192 water samples were collected at eight groundwater sites and one surface water site. Through laboratory analysis we found the highest measured concentration of Cr to be 54.07 μg/L, and the measured concentration of Zn was in …

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Numerical Modeling Of The Interactions Between Nonlinear Waves And Arbitrarily Flexible Vegetation, Navid Tahvildari Jan 2017

Numerical Modeling Of The Interactions Between Nonlinear Waves And Arbitrarily Flexible Vegetation, Navid Tahvildari

Civil & Environmental Engineering Faculty Publications

Coastal wetlands are among the natural features with the capability to dissipate wave energy and reduce storm damage. Inadequate representation of wave and vegetation characteristics in numerical models may reduce their capability in predicting wave processes over wetlands. Previous numerical wave models have typically applied simplifications on vegetation behavior. For instance, vegetation stems were usually assumed to be rigid or semi-flexible and thus extreme stem deflections could not be captured. In this study, a time-domain nonlinear numerical model based on extended Boussinesq formulation is developed and coupled with a numerical model for vegetation blade dynamics that allows for arbitrary flexibility. …

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Effects Of Nonaerated Circulation Water Velocity On Nutrient Release From Aquaculture Pond Sediments, Xiangju Cheng, Dantong Zhu, Xixi Wang, Deguang Yu, Jun Xie Jan 2017

Effects Of Nonaerated Circulation Water Velocity On Nutrient Release From Aquaculture Pond Sediments, Xiangju Cheng, Dantong Zhu, Xixi Wang, Deguang Yu, Jun Xie

Civil & Environmental Engineering Faculty Publications

Sustaining good water quality in aquaculture ponds is vital. Without an aerator, the dissolved oxygen in ponds comes primarily from mass transfer at the water-ambient atmosphere interface. As sediment can seriously affect water quality, this study used indoor experiments to examine the nutrient (nitrogen and phosphorus) release mechanisms and fluxes from sediment in aquaculture ponds with moving water but no aeration. The results showed that the ammonia nitrogen (NH3-N) concentration in the overlying water was inversely proportional to flow velocity and that a higher flow velocity tended to result in a lower concentration in the overlying water, a …

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Representing And Inferring Mental Workload Via Defeasible Reasoning: A Comparison With The Nasa Task Load Index And The Workload Profile, Lucas Middeldorf Rizzo, Luca Longo Jan 2017

Representing And Inferring Mental Workload Via Defeasible Reasoning: A Comparison With The Nasa Task Load Index And The Workload Profile, Lucas Middeldorf Rizzo, Luca Longo

Conference papers

The NASA Task Load Index (NASA − TLX) and the Workload Profile (WP) are likely the most employed instruments for subjective mental workload (MWL) measurement. Numerous areas have made use of these methods for assessing human performance and thusly improving the design of systems and tasks. Unfortunately, MWL is still a vague concept, with different definitions and no universal measure. This research investigates the use of defeasible reasoning to represent and assess MWL. Reasoning is defeasible when a conclusion, supported by a set of premises, can be retracted in the light of new information. In this empirical study, this type …

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The Influence Of Values On The Intention And Usage Of Mobile Phone Technology:A Case Of Tanzanian Smes, Renatus Mushi, Almar Ennis, Deirdre Lillis, Said Jafari Jan 2017

The Influence Of Values On The Intention And Usage Of Mobile Phone Technology:A Case Of Tanzanian Smes, Renatus Mushi, Almar Ennis, Deirdre Lillis, Said Jafari

Conference papers

Mobile phone technology has been relied upon in performing a number of activities in the SMEs. In less developed regions, computing infrastructures are very poor thereby depending highly on mobile phones. The improvement of technology in the mobile phones has seen more applications and services being accessed through them. This gives SMEs, especially in developing countries, a preferable alternative to desktop computing technology. However, to maximise the usability of mobile phone technology in SMEs context, key factors which influence users’ perception on its acceptance need to be explained clearly. This study explains the factors influencing employees’ intentions and use of …

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Phytoplankton Plastid Proteomics: Cracking Open Diatoms To Understand Plastid Biochemistry Under Iron Limitation, Skyler J. Nunn, Phoebe Dreux Chappell, Kristofer Gomes, Anasthasia Bonderenko, Bethany D. Jenkins, Brook L. Nunn Jan 2017

Phytoplankton Plastid Proteomics: Cracking Open Diatoms To Understand Plastid Biochemistry Under Iron Limitation, Skyler J. Nunn, Phoebe Dreux Chappell, Kristofer Gomes, Anasthasia Bonderenko, Bethany D. Jenkins, Brook L. Nunn

OES Faculty Publications

Diatoms, such as Thalassiosira pseudonana, are important oceanic primary producers, as they sequester carbon dioxide (CO₂) out of the atmosphere, die, and precipitate to the ocean floor. In many areas of the world’s oceans, phytoplankton, such as diatoms, are limited in growth by the availability of iron (Fe). Fe is an essential nutrient for phytoplankton, as it is central in the electron transport chain component of photosynthesis. Through this study, we examined if Fe-limitation makes a significant difference in the proteins expressed within the chloroplast, the power source for diatoms. Here, we utilized a new plastid isolation technique specific …

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Gorenstein Injective Envelopes And Covers Over Two Sided Noetherian Rings, Alina Iacob Jan 2017

Gorenstein Injective Envelopes And Covers Over Two Sided Noetherian Rings, Alina Iacob

Mathematical Sciences: Faculty Publications

We prove that the class of Gorenstein injective modules is both enveloping and covering over a two sided noetherian ring such that the character modules of Gorenstein injective modules are Gorenstein flat. In the second part of the paper we consider the connection between the Gorenstein injective modules and the strongly cotorsion modules. We prove that when the ring R is commutative noetherian of finite Krull dimension, the class of Gorenstein injective modules coincides with that of strongly cotorsion modules if and only if the ring R is in fact Gorenstein.

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Elevated Trace Metal Content Of Prokaryotic Communities Associated With Marine Oxygen Deficient Zones, Daniel C. Ohnemus, Sara Rauschenberg, Gregory A. Cutter, Jessica N. Fitzsimmons, Robert M. Sherrell, Benjamin S. Twining Jan 2017

Elevated Trace Metal Content Of Prokaryotic Communities Associated With Marine Oxygen Deficient Zones, Daniel C. Ohnemus, Sara Rauschenberg, Gregory A. Cutter, Jessica N. Fitzsimmons, Robert M. Sherrell, Benjamin S. Twining

OES Faculty Publications

Little is known about the trace metal content of marine prokaryotes, in part due to their co-occurrence with more abundant particulate phases in the upper ocean, such as phytoplankton and biogenic detritus, lithogenic minerals, and authigenic Mn and Fe oxyhydroxides. We attempt to isolate these biomass signals in particulate data from the US GEOTRACES Eastern Pacific Zonal Transect (cruise GP16) in the Eastern Tropical South Pacific (ETSP), which exhibited consistent maxima in P and other bioactive trace metals, and minima in particulate Mn, in the oxygen deficient zones (ODZs) of 13 stations. Nitrite maxima and nitrate deficits indicated the presence …

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Critical Decisions In Metaproteomics: Achieving High Confidence Protein Annotations In A Sea Of Unknowns, Emma Timmins-Schiffman, Damon H. May, Molly Mikan, Michael Riffle, Chris Frazar, H. R. Harvey, William S. Noble, Brook L. Nunn Jan 2017

Critical Decisions In Metaproteomics: Achieving High Confidence Protein Annotations In A Sea Of Unknowns, Emma Timmins-Schiffman, Damon H. May, Molly Mikan, Michael Riffle, Chris Frazar, H. R. Harvey, William S. Noble, Brook L. Nunn

OES Faculty Publications

No abstract provided.

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Community Production Modulates Coral Reef Ph And The Sensitivity Of Ecosystem Calcification To Ocean Acidification, Thomas M. Decarlo, Anne L. Cohen, George T. F. Wong, Fuh-Kwo Shiah, Steven J. Lentz, Kristen A. Davis, Kathryn E. F. Shamberger, Pat Lohmann Jan 2017

Community Production Modulates Coral Reef Ph And The Sensitivity Of Ecosystem Calcification To Ocean Acidification, Thomas M. Decarlo, Anne L. Cohen, George T. F. Wong, Fuh-Kwo Shiah, Steven J. Lentz, Kristen A. Davis, Kathryn E. F. Shamberger, Pat Lohmann

OES Faculty Publications

Coral reefs are built of calcium carbonate (CaCO3) produced biogenically by a diversity of calcifying plants, animals, and microbes. As the ocean warms and acidifies, there is mounting concern that declining calcification rates could shift coral reef CaCO3 budgets from net accretion to net dissolution. We quantified net ecosystem calcification (NEC) and production (NEP) on Dongsha Atoll, northern South China Sea, over a 2 week period that included a transient bleaching event. Peak daytime pH on the wide, shallow reef flat during the nonbleaching period was ~8.5, significantly elevated above that of the surrounding open ocean (~8.0-8.1) as …

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Effects Of Climate Oscillations On Wildland Fire Potential In The Continental United States, Shelby A. Mason, Peter E. Hamlington, Benjamin D. Hamlington, W. Matt Jolly, Chad M. Hoffman Jan 2017

Effects Of Climate Oscillations On Wildland Fire Potential In The Continental United States, Shelby A. Mason, Peter E. Hamlington, Benjamin D. Hamlington, W. Matt Jolly, Chad M. Hoffman

OES Faculty Publications

The effects of climate oscillations on spatial and temporal variations in wildland fire potential in the continental U.S. are examined from 1979 to 2015 using cyclostationary empirical orthogonal functions (CSEOFs). The CSEOF analysis isolates effects associated with the modulated annual cycle and the El Nino-Southern Oscillation (ENSO). The results show that, in early summer, wildland fire potential is reduced in the southwest during El Nino but is increased in the northwest, with opposite trends for La Nina. In late summer, El Nino is associated with increased wildland fire potential in the southwest. Relative to the mean, the largest impacts of …

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Impact Of Glacial/Interglacial Sea Level Change On The Ocean Nitrogen Cycle, Haojia Ren, Daniel M. Sigman, Alfredo Martínez-García, Robert F. Anderson, Chen Min-Te, Ana Christina Ravelo, Marietta Straub, George T. F. Wong, Gerald H. Haug Jan 2017

Impact Of Glacial/Interglacial Sea Level Change On The Ocean Nitrogen Cycle, Haojia Ren, Daniel M. Sigman, Alfredo Martínez-García, Robert F. Anderson, Chen Min-Te, Ana Christina Ravelo, Marietta Straub, George T. F. Wong, Gerald H. Haug

OES Faculty Publications

The continental shelves are the most biologically dynamic regions of the ocean, and they are extensive worldwide, especially in the western North Pacific. Their area has varied dramatically over the glacial/interglacial cycles of the last million years, but the effects of this variation on ocean biological and chemical processes remain poorly understood. Conversion of nitrate to N2 by denitrification in sediments accounts for half or more of the removal of biologically available nitrogen ("fixed N") from the ocean. The emergence of continental shelves during ice ages and their flooding during interglacials have been hypothesized to drive changes in sedimentary denitrification. …

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Widespread Infilling Of Tidal Channels And Navigable Waterways In The Human-Modified Tidal Deltaplain Of Southwest Bangladesh, C. Wilson, S. Goodbred, C. Small, J. Gilligan, S. Sams, B. Mallick, R. Hale Jan 2017

Widespread Infilling Of Tidal Channels And Navigable Waterways In The Human-Modified Tidal Deltaplain Of Southwest Bangladesh, C. Wilson, S. Goodbred, C. Small, J. Gilligan, S. Sams, B. Mallick, R. Hale

OES Faculty Publications

Since the 1960s, ~5000 km2 of tidal deltaplain in southwest Bangladesh has been embanked and converted to densely inhabited, agricultural islands (i.e., polders). This landscape is juxtaposed to the adjacent Sundarbans, a pristine mangrove forest, both well connected by a dense network of tidal channels that effectively convey water and sediment throughout the region. The extensive embanking in poldered areas, however, has greatly reduced the tidal prism (i.e., volume of water) transported through local channels. We reveal that >600 km of these major waterways have infilled in recent decades, converting to land through enhanced sedimentation and the direct blocking …

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