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Articles 91 - 120 of 305
Full-Text Articles in Social and Behavioral Sciences
Electron Affinities, Well Depths, And Vibrational Spectroscopy Of Cis- And Trans-Hoco, Christopher J. Johnson, Michael E. Harding, Berwyck L. J Poad, John F. Stanton, Robert E. Continetti
Electron Affinities, Well Depths, And Vibrational Spectroscopy Of Cis- And Trans-Hoco, Christopher J. Johnson, Michael E. Harding, Berwyck L. J Poad, John F. Stanton, Robert E. Continetti
Berwyck L. J. Poad
We report vibrationally resolved photoelectron spectra of internally cold HOCO– and DOCO– anions at wavelengths near and well above the detachment threshold. These spectra are dominated by a strong Franck–Condon progression of three low-energy modes of the cis isomer, the first gas-phase measurement of these vibrations. Using highly resolved, near-threshold spectra we are able to reassign the electron affinities (EAs) of cis- and trans-HOCO to 1.51 ± 0.01 and 1.37 ± 0.01 eV, respectively. Using these EAs, well depths with respect to OH + CO are determined to be 1.07 ± 0.02 eV for trans-HOCO and 0.99 ± 0.02 eV …
Rotationally Resolved Infrared Spectrum Of The Na+-D2 Complex: An Experimental And Theoretical Study, Berwyck L. Poad, V Dryza, J Klos, A A. Buchachenko, E J. Bieske
Rotationally Resolved Infrared Spectrum Of The Na+-D2 Complex: An Experimental And Theoretical Study, Berwyck L. Poad, V Dryza, J Klos, A A. Buchachenko, E J. Bieske
Berwyck L. J. Poad
The infrared spectrum of mass-selected Na+-D2 complexes is recorded in the D-D stretch vibration region (2915-2972 cm−1) by detecting Na+ photofragments resulting from photo-excitation of the complexes. Analysis of the rotationally resolved spectrum confirms a T-shaped equilibrium geometry for the complex and a vibrationally averaged intermolecular bond length of 2.461 Å. The D-D stretch band centre occurs at 2944.04 cm−1, representing a −49.6 cm−1 shift from the Q1(0) transition of the free D2 molecule. Variational rovibrational energy level calculations are performed for Na+-D2 utilising an ab initio potential energy surface developed previously for investigating the Na+-H2 complex [B. L. J. …
Photoelectron-Photofragment Coincidence Spectroscopy In A Cryogenically Cooled Linear Electrostatic Ion Beam Trap, Christopher J. Johnson, Ben B. Shen, Berwyck L. J Poad, Robert E. Continetti
Photoelectron-Photofragment Coincidence Spectroscopy In A Cryogenically Cooled Linear Electrostatic Ion Beam Trap, Christopher J. Johnson, Ben B. Shen, Berwyck L. J Poad, Robert E. Continetti
Berwyck L. J. Poad
A cryogenically cooled linear electrostatic ion beam trap for use in photoelectron-photofragment coincidence (PPC) spectroscopy is described. Using this instrument, anions created in cold, low-dutycycle sources can be stored for many seconds in a ∼20 K environment to cool radiatively, removing energetic uncertainties due to vibrationally excited precursor anions. This apparatus maintains a well-collimated beam necessary for high-resolution fragment imaging and the high experimental duty cycle needed for coincidence experiments. Ion oscillation is bunched and phase-locked to a modelocked laser, ensuring temporal overlap between ion bunches and laser pulses and that ions are intersected by the laser only when travelling …
Infrared Spectra Of Cl-_(C6h6)Mm=1, 2, Christopher Thompson, Berwyck Poad, Corinna Emmeluth, Evan Bieske
Infrared Spectra Of Cl-_(C6h6)Mm=1, 2, Christopher Thompson, Berwyck Poad, Corinna Emmeluth, Evan Bieske
Berwyck L. J. Poad
The Cl--(C6H6)Arn n = 0,1,2 and Cl--(C6H6)2 complexes are investigated using photodissociation infrared spectroscopy in the CH stretch region and through ab initio calculations at the MP2/aug-cc-pVDZ level. The results indicate that Cl--C6H6 possesses a planar structure in which the benzene molecule is attached to the Cl- anion by a double hydrogen bond. The calculations predict that Cl (C6H6)2 has a C2 symmetry structure in which the two face-to-face benzene molecules are attached to …
Infrared Spectra Of Mass-Selected Mg+-H2 And Mg +-D2 Complexes, Viktoras Dryza, Berwyck L. Poad, Evan J. Bieske
Infrared Spectra Of Mass-Selected Mg+-H2 And Mg +-D2 Complexes, Viktoras Dryza, Berwyck L. Poad, Evan J. Bieske
Berwyck L. J. Poad
Rotationally resolved infrared spectra of Mg(+)-H(2) and Mg(+)-D(2) are recorded in the H-H (4025-4080 cm(-1)) and D-D (2895-2945 cm(-1)) stretch regions by monitoring Mg(+) photofragments. The nu(HH) and nu(DD) transitions of Mg(+)-H(2) and Mg(+)-D(2) are red-shifted by 106.2 +/- 1.5 and 76.0 +/- 0.1 cm(-1) respectively from the fundamental vibrational transitions of the free H(2) and D(2) molecules. The spectra are consistent with a T-shaped equilibrium structure in which the Mg(+) ion interacts with a slightly perturbed H(2) or D(2) molecule. From the spectroscopic constants, a vibrationally averaged intermolecular separation of 2.716 A (2.687 A) is deduced for the ground …
Reactions Of Simple And Peptidic Alpha-Carboxylate Radical Anions With Dioxygen In The Gas Phase, Tony Ly, Benjamin B. Kirk, Pramesh I. Hettiarachchi, Berwyck L. Poad, Adam J. Trevitt, Gabriel Da Silva, Stephen J. Blanksby
Reactions Of Simple And Peptidic Alpha-Carboxylate Radical Anions With Dioxygen In The Gas Phase, Tony Ly, Benjamin B. Kirk, Pramesh I. Hettiarachchi, Berwyck L. Poad, Adam J. Trevitt, Gabriel Da Silva, Stephen J. Blanksby
Berwyck L. J. Poad
α-Carboxylate radical anions are potential reactive intermediates in the free radical oxidation of biological molecules (e.g., fatty acids, peptides and proteins). We have synthesised well-defined α-carboxylate radical anions in the gas phase by UV laser photolysis of halogenated precursors in an ion-trap mass spectrometer. Reactions of isolated acetate (CH2CO 2-) and 1-carboxylatobutyl (CH3CH 2CH2CHCO2-) radical anions with dioxygen yield carbonate (CO3-) radical anions and this chemistry is shown to be a hallmark of oxidation in simple and alkyl-substituted cross-conjugated species. Previous solution phase studies have shown that Cα-radicals in peptides, formed from free radical damage, combine with dioxygen to form …
Spectroscopic Study Of The Benchmark Mn+-H2 Complex, Viktoras Dryza, Berwyck L. J Poad, Evan J. Bieske
Spectroscopic Study Of The Benchmark Mn+-H2 Complex, Viktoras Dryza, Berwyck L. J Poad, Evan J. Bieske
Berwyck L. J. Poad
We have recorded the rotationally resolved infrared spectrum of the weakly bound Mn+-H2 complex in the H-H stretch region (4022-4078 cm(-1)) by monitoring Mn+ photodissociation products. The band center of Mn+-H2, the H-H stretch transition, is shifted by -111.8 cm(-1) from the transition of the free H2 molecule. The spectroscopic data suggest that the Mn+-H2 complex consists of a slightly perturbed H2 molecule attached to the Mn+ ion in a T-shaped configuration with a vibrationally averaged intermolecular separation of 2.73 A. Together with the measured Mn+...H2 binding energy of 7.9 kJ/mol (Weis, P.; et al. J. Phys. Chem. A 1997, …
Holocene Palaeofire Records In A High-Level, Proximal Valley-Fill (Wilson Bog), Mount Lofty Ranges, South Australia, Solomon Buckman, Katherine Brownlie, Robert Bourman, C. Murray-Wallace, Rowena Morris, Terry Lachlan, Richard Roberts, Lee Arnold, J. Cann
Holocene Palaeofire Records In A High-Level, Proximal Valley-Fill (Wilson Bog), Mount Lofty Ranges, South Australia, Solomon Buckman, Katherine Brownlie, Robert Bourman, C. Murray-Wallace, Rowena Morris, Terry Lachlan, Richard Roberts, Lee Arnold, J. Cann
Richard G Roberts
No abstract provided.
Initial Speleothem Results From Western Flores And Eastern Java, Indonesia: Were Climate Changes From 47 To 5ka Responsible For The Extinction Of Homo Floresiensis?, Richard Roberts, Allan Chivas, T. Sutikna, Michael Morwood, J Zhao, Kira Westaway
Initial Speleothem Results From Western Flores And Eastern Java, Indonesia: Were Climate Changes From 47 To 5ka Responsible For The Extinction Of Homo Floresiensis?, Richard Roberts, Allan Chivas, T. Sutikna, Michael Morwood, J Zhao, Kira Westaway
Richard G Roberts
No abstract provided.
A Southern Indian Middle Palaeolithic Occupation Surface Sealed By The 74 Ka Toba Eruption: Further Evidence From Jwalapuram Locality 22, Richard Roberts, Allan Chivas, Christopher Clarkson, Ravi Korisettar, Nicole Boivin, Michael Petraglia, Peter Ditchfield, Michael Haslam, Janardhana Bora, Sanjay Eksambekar, Victoria Smith, Anna Oh, Clair Harris
A Southern Indian Middle Palaeolithic Occupation Surface Sealed By The 74 Ka Toba Eruption: Further Evidence From Jwalapuram Locality 22, Richard Roberts, Allan Chivas, Christopher Clarkson, Ravi Korisettar, Nicole Boivin, Michael Petraglia, Peter Ditchfield, Michael Haslam, Janardhana Bora, Sanjay Eksambekar, Victoria Smith, Anna Oh, Clair Harris
Richard G Roberts
No abstract provided.
Dirt, Dates And Dna:Osl And Radiocarbon Chronologies Of Perenially Frozen Sediments In Siberia, And Their Implications For Sedimentary Ancient Dna Studies, Lee Arnold, Richard Roberts, Ross Macphee, James Haile, Fiona Brock, Per Moller, Duane Froese, Alexei Tikhonov, Allan Chivas, M. Thomas Gilbert, Eske Willerslev
Dirt, Dates And Dna:Osl And Radiocarbon Chronologies Of Perenially Frozen Sediments In Siberia, And Their Implications For Sedimentary Ancient Dna Studies, Lee Arnold, Richard Roberts, Ross Macphee, James Haile, Fiona Brock, Per Moller, Duane Froese, Alexei Tikhonov, Allan Chivas, M. Thomas Gilbert, Eske Willerslev
Richard G Roberts
The sedimentary ancient DNA (sedaDNA) technique offers a potentially invaluable means of investigating species evolution and extinction dynamics in high-latitude environments. An implicit assumption of the sedaDNA approach is that the extracted DNA is autochthonous with the host deposit and that it has not been physically transported from older source deposits or reworked within the sedimentary profile by postdepositional mixing. In this paper we investigate whether these fundamental conditions are upheld at seven perennially frozen wetland sites across the Taimyr Peninsula and coastal lowlands of north-central Siberia. Optically stimulated luminescence (OSL) and radiocarbon (14C) dating are used to constrain the …
The Evolving Landscape And Climate Of Western Flores: An Environmental Context For The Archaeological Site Of Liang Bua, Kira Westaway, Richard Roberts, T Sutikna, Michael Morwood, R Drysdale, J Zhao, Allan Chivas
The Evolving Landscape And Climate Of Western Flores: An Environmental Context For The Archaeological Site Of Liang Bua, Kira Westaway, Richard Roberts, T Sutikna, Michael Morwood, R Drysdale, J Zhao, Allan Chivas
Richard G Roberts
The rapidly changing landscape of the eastern Indonesian archipelago has evolved at a pace dictated by its tropical climate and its geological and tectonic history. This has produced accelerated karstification, flights of alluvial terraces, and complex, multi-level cave systems. These cave systems sometimes contain a wealth of archaeological evidence, such as the almost complete skeleton of Homo floresiensis found at the site of Liang Bua in western Flores, but this information can only be understood in the context of the geomorphic history of the cave, and the more general geological, tectonic, and environmental histories of the river valley and region. …
Ten Trenches: A Scienceart Collaboration, Timothy J. Cohen, Martin Cohen, Stephanie Kermode, Michael G. Leggett
Ten Trenches: A Scienceart Collaboration, Timothy J. Cohen, Martin Cohen, Stephanie Kermode, Michael G. Leggett
Faculty of Science - Papers (Archive)
Collaborative and cross-disciplinary research by a group of artists and scientists in an Australian rural setting generates data and ideas that form the basis of a wider understanding of the ramifications of global warming and cooling within the local, regional and national community. The work is viewed as an initial educational platform that will allow the public to see and understand the complexities of climate-based research.
Combining Mbr And Nf/Ro Membrane Filtration For The Removal Of Trace Organics In Indirect Potable Water Reuse Applications, William Price, Nichanan Tadkaew, Long Nghiem, Stuart Khan, Abdulhakeem Alturki, James Mcdonald
Combining Mbr And Nf/Ro Membrane Filtration For The Removal Of Trace Organics In Indirect Potable Water Reuse Applications, William Price, Nichanan Tadkaew, Long Nghiem, Stuart Khan, Abdulhakeem Alturki, James Mcdonald
Long D Nghiem
The aim of this study was to demonstrate the complementarities of combining membrane bioreactor (MBR) treatment with nanofiltration (NF) or reverse osmosis (RO) membrane filtration for the removal of trace organic contaminants for potential indirect potable water recycling applications. Four commercially available NF/RO membranes, namely NF270, NF90, BW30 and ESPA2, were selected for this investigation. Challenge tests were conducted with 40 trace organic compounds at concentrations of approximately 2 ng/L in initial wastewater solutions using a laboratory scaleMBRsystem and a cross-flow NF/RO rig. The results suggest that the MBR system effectively removes hydrophobic and biodegradable trace organic compounds. The adsorption …
Reactions Of Simple And Peptidic Alpha-Carboxylate Radical Anions With Dioxygen In The Gas Phase, Tony Ly, Benjamin B. Kirk, Pramesh I. Hettiarachchi, Berwyck L. Poad, Adam J. Trevitt, Gabriel Da Silva, Stephen J. Blanksby
Reactions Of Simple And Peptidic Alpha-Carboxylate Radical Anions With Dioxygen In The Gas Phase, Tony Ly, Benjamin B. Kirk, Pramesh I. Hettiarachchi, Berwyck L. Poad, Adam J. Trevitt, Gabriel Da Silva, Stephen J. Blanksby
Stephen Blanksby
α-Carboxylate radical anions are potential reactive intermediates in the free radical oxidation of biological molecules (e.g., fatty acids, peptides and proteins). We have synthesised well-defined α-carboxylate radical anions in the gas phase by UV laser photolysis of halogenated precursors in an ion-trap mass spectrometer. Reactions of isolated acetate (CH2CO 2-) and 1-carboxylatobutyl (CH3CH 2CH2CHCO2-) radical anions with dioxygen yield carbonate (CO3-) radical anions and this chemistry is shown to be a hallmark of oxidation in simple and alkyl-substituted cross-conjugated species. Previous solution phase studies have shown that Cα-radicals in peptides, formed from free radical damage, combine with dioxygen to form …
A Petrological, Mineralogical And Geochemical Analysis Of Listwaenite Alteration At Spring Creek Bingara In The Great Serpentinite Belt, New England, Nsw, E Holcroft, Solomon Buckman, I Neuss
A Petrological, Mineralogical And Geochemical Analysis Of Listwaenite Alteration At Spring Creek Bingara In The Great Serpentinite Belt, New England, Nsw, E Holcroft, Solomon Buckman, I Neuss
Solomon Buckman Dr.
No abstract provided.
Silica-Carbonate (Listwanites) Related Gold Mineralisation Associated With Epithermal Alteration Of Serpentinite Bodies, Solomon Buckman, P Ashley
Silica-Carbonate (Listwanites) Related Gold Mineralisation Associated With Epithermal Alteration Of Serpentinite Bodies, Solomon Buckman, P Ashley
Solomon Buckman Dr.
No abstract provided.
Using Lidar To Assess The Effect Of Fire And Floods On Upland Peat Bogs, Waterfall Gully, Mount Lofty Ranges, South Australia, Javier Leon Patino, Solomon Buckman, Robert P. Bourman, Rowena Morris, Katherine C. Brownlie
Using Lidar To Assess The Effect Of Fire And Floods On Upland Peat Bogs, Waterfall Gully, Mount Lofty Ranges, South Australia, Javier Leon Patino, Solomon Buckman, Robert P. Bourman, Rowena Morris, Katherine C. Brownlie
Solomon Buckman Dr.
A flood exceeding the 100 year average recurrence interval in November 2005 led to the failure of an upland peat bog in Waterfall Gully. The area is prone to severe bushfire and flood events and the control dam at the base of First Falls was filled with sediment sourced from Wilson Bog. A resistant quartzite bar at Fourth Falls has formed a natural constriction point against which burnt logs and debris have collected following previous fire events forming a natural dam resulting in sediment/peat accumulation upstream. The failure of the bog was inevitable as the vegetative material in the log-jam …
The Dirt On Assessing Post-Fire Erosion In The Mount Lofty Ranges: Comparing Methods, Rowena H. Morris, Solomon Buckman, Paul Connelly, Deirdre Dragovich, Bertram Ostendorf, Ross A. Bradstock
The Dirt On Assessing Post-Fire Erosion In The Mount Lofty Ranges: Comparing Methods, Rowena H. Morris, Solomon Buckman, Paul Connelly, Deirdre Dragovich, Bertram Ostendorf, Ross A. Bradstock
Solomon Buckman Dr.
Land managers are required to assess a range of environmental attributes prior to and after prescribed burning. Current environmental assessments vary depending on the organisation involved and the existing information about localised soil erosion. Auditing successful environmental assessments requires ongoing field monitoring to evaluate whether the magnitude and extent of predicted post-fire impacts are comparable. The impacts of post-fire erosion were assessed by the authors using the techniques of water sampling, sediment traps, erosion pins, laser scanning, photogrammetry and visual field assessment. Each data collecting method varies in its spatial and temporal reach in terms of monitoring landscape changes in …
Soil Geochemistry And Pathfinder Element Distribution Associated With The Hillgrove Antimony-Gold-Tungsten Deposit, New England Orogen, Nsw, R Ellsmore, Solomon Buckman, C Simpson
Soil Geochemistry And Pathfinder Element Distribution Associated With The Hillgrove Antimony-Gold-Tungsten Deposit, New England Orogen, Nsw, R Ellsmore, Solomon Buckman, C Simpson
Solomon Buckman Dr.
No abstract provided.
Accordion Vs. Quantum Tectonics: Insights Into Continental Growth Processes From The Paleozoic Of Eastern Gondwanan, Jonathan C. Aitchison, Solomon Buckman
Accordion Vs. Quantum Tectonics: Insights Into Continental Growth Processes From The Paleozoic Of Eastern Gondwanan, Jonathan C. Aitchison, Solomon Buckman
Solomon Buckman Dr.
The Early Paleozoic Lachlan Fold Belt of eastern Australia is widely regarded as an ancient convergent plate margin beneath which paleo-Pacific (Panthalassic) oceanic lithosphere was continuously subducted. It is cited as the type example of a retreating accretionary orogeny. However, sandstone compositions, the sedimentological nature and timing of chert accumulation and overall stratigraphic architecture are not necessarily consistent with this model. We suggest an alternative explanation for growth of Gondwanan continental margin. Oceanic lithosphere outboard of the passive Gondwana continental margin was subducted beneath an extensive intra-oceanic island arc that now crops out as an allochthonous element (Macquarie arc) within …
Managing Our Waste, Faisal Ibney Hai
A Study On Solid Waste Management System Of Dhaka City Corporation: Effect Of Composting And Landfill Location, Faisal Ibney Hai, M. Ashraf Ali
A Study On Solid Waste Management System Of Dhaka City Corporation: Effect Of Composting And Landfill Location, Faisal Ibney Hai, M. Ashraf Ali
Faisal I Hai
This study has analyzed the generation and characteristics of solid waste in Dhaka city, along with the associated environmental impacts and existing solid waste management practices. Special focus was given on the effect of composting on final disposal of solid waste and effect of landfill site location on transportation cost. An estimate of the future generation rate indicates that the present generation rate of 3500 tons/day may exceed 30 thousand tons/day by the year 2020.The mixed waste dumped at dumping sites is characterized with high organic content and high moisture content (about 80% and 50-70% by weight, respectively). According to …
Approaches To Development Of A User-Friendly Community Based Arsenic/Iron Removal Unit In Bangladesh, Khondoker Mahabub Hassan, Farooque Ahmed, Faisal Hai, Saleh Faraj Magram
Approaches To Development Of A User-Friendly Community Based Arsenic/Iron Removal Unit In Bangladesh, Khondoker Mahabub Hassan, Farooque Ahmed, Faisal Hai, Saleh Faraj Magram
Faisal I Hai
The present stydy focuses on the strategies to modify the design of a community based Arsenic - Iron Removal Unit (AIRU) based on the field performance of the AIRU and the feedback from the users. The ultimate aim was to offer a user-friendly and sustainable system. Appropriate modifications in the design of the developed unit reduced the propensities of water head-loss and media clogging, thereby yielding sustained flow rate. Introduction of a simple cleaning procerdure (98% flow-recovery with three successive backwashing sequences) successfully reduced the frequency of requirement of labor-intensive replacement of the whole filter media. Raw water with arsenic …
Chemically Activated Reactions On The C7h5 Energy Surface: Propargyl + Diacetylene, I-C5h3 + Acetylene, And N-C5h3 + Acetylene, Gabriel Da Silva, Adam J. Trevitt
Chemically Activated Reactions On The C7h5 Energy Surface: Propargyl + Diacetylene, I-C5h3 + Acetylene, And N-C5h3 + Acetylene, Gabriel Da Silva, Adam J. Trevitt
Adam Trevitt
This study uses computational chemistry and statistical reaction rate theory to investigate the chemically activated reaction of diacetylene (butadiyne, C4H2) with the propargyl radical (C •H2CCH) and the reaction of acetylene (C 2H2) with the i-C5H3 (CH 2CCCC•H) and n-C5H3 (CHCC •HCCH) radicals. A detailed G3SX-level C7H 5 energy surface demonstrates that the C3H3 + C4H2 and C5H3 + C2H 2 addition reactions proceed with moderate barriers, on the order of 10 to 15 kcal mol-1, and form activated open-chain C 7H5 species that can isomerize to the fulvenallenyl radical with the highest barrier still significantly below the entrance channel …
Products Of The Benzene + O(3p) Reaction, Craig A. Taatjes, David L. Osborn, Talitha M. Selby, Giovanni Meloni, Adam J. Trevitt, Evgeny Epifanovsky, Anna I. Krylov, Baptiste Sirjean, Enoch Dames, Hai Wang
Products Of The Benzene + O(3p) Reaction, Craig A. Taatjes, David L. Osborn, Talitha M. Selby, Giovanni Meloni, Adam J. Trevitt, Evgeny Epifanovsky, Anna I. Krylov, Baptiste Sirjean, Enoch Dames, Hai Wang
Adam Trevitt
No abstract provided.
Reaction Of The C2h Radical With 1-Butyne (C4h6): Low Temperature Kinetics And Isomer-Specific Product Detection, Satchin Soorkia, Adam J. Trevitt, Talitha M. Selby, David L. Osborn, Craig A. Taatjes, Kevin R. Wilson, Stephen R. Leone
Reaction Of The C2h Radical With 1-Butyne (C4h6): Low Temperature Kinetics And Isomer-Specific Product Detection, Satchin Soorkia, Adam J. Trevitt, Talitha M. Selby, David L. Osborn, Craig A. Taatjes, Kevin R. Wilson, Stephen R. Leone
Adam Trevitt
No abstract provided.
Reactions Of The Cn Radical With Benzene And Toluene: Product Detection And Low-Temperature Kinetics, Adam J. Trevitt, Fabien Goulay, Craig A. Taatjes, David L. Osborn, Stephen R. Leone
Reactions Of The Cn Radical With Benzene And Toluene: Product Detection And Low-Temperature Kinetics, Adam J. Trevitt, Fabien Goulay, Craig A. Taatjes, David L. Osborn, Stephen R. Leone
Adam Trevitt
Low-temperature rate coefficients are measured for the CN + benzene and CN + toluene reactions using the pulsed Laval nozzle expansion technique coupled with laser-induced fluorescence detection. The CN + benzene reaction rate coefficient at 105, 165, and 295 K is found to be relatively constant over this temperature range, (3.9−4.9) × 10−10 cm3 molecule−1 s−1. These rapid kinetics, along with the observed negligible temperature dependence, are consistent with a barrierless reaction entrance channel and reaction efficiencies approaching unity. The CN + toluene reaction is measured to have a rate coefficient of 1.3 × 10−10 cm3 molecule−1 s−1 at 105 …
Reactions Of Simple And Peptidic Alpha-Carboxylate Radical Anions With Dioxygen In The Gas Phase, Tony Ly, Benjamin B. Kirk, Pramesh I. Hettiarachchi, Berwyck L. Poad, Adam J. Trevitt, Gabriel Da Silva, Stephen J. Blanksby
Reactions Of Simple And Peptidic Alpha-Carboxylate Radical Anions With Dioxygen In The Gas Phase, Tony Ly, Benjamin B. Kirk, Pramesh I. Hettiarachchi, Berwyck L. Poad, Adam J. Trevitt, Gabriel Da Silva, Stephen J. Blanksby
Adam Trevitt
α-Carboxylate radical anions are potential reactive intermediates in the free radical oxidation of biological molecules (e.g., fatty acids, peptides and proteins). We have synthesised well-defined α-carboxylate radical anions in the gas phase by UV laser photolysis of halogenated precursors in an ion-trap mass spectrometer. Reactions of isolated acetate (CH2CO 2-) and 1-carboxylatobutyl (CH3CH 2CH2CHCO2-) radical anions with dioxygen yield carbonate (CO3-) radical anions and this chemistry is shown to be a hallmark of oxidation in simple and alkyl-substituted cross-conjugated species. Previous solution phase studies have shown that Cα-radicals in peptides, formed from free radical damage, combine with dioxygen to form …
Climate Change In The Dead Heart Of Australia, Joshua Larsen, Gerald C. Nanson, Timothy J. Cohen, Brian G. Jones, John D. Jansen, Jan-Hendrik May
Climate Change In The Dead Heart Of Australia, Joshua Larsen, Gerald C. Nanson, Timothy J. Cohen, Brian G. Jones, John D. Jansen, Jan-Hendrik May
Timothy Cohen
Despite the absence of large-scale glaciation, the Australian continent has experienced substantial environmental change throughout the Quaternary period. This is especially pronounced in central Australia, where one seventh of the continent is drained internally to the depocentre, and lowest point in Australia, Lake Eyre (Figure 1). Research has shown that at one time, large sandy braided and meandering rivers carried water through dunefields to a large freshwater lake system. Today, the rivers are hostage to the dunefield, and floodwaters might only reach Lake Eyre once every ten years or so. In order to understand the development of this arid desert …