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Full-Text Articles in Physical Sciences and Mathematics
Assessing Soil Remobilisation In Catchments Using A 137 Cs-Sediment Hillslope Model, Ava D. Simms, Colin D. Woodroffe, Brian G. Jones, Henk Heijnis, Jennifer Harrison, Rob Mann
Assessing Soil Remobilisation In Catchments Using A 137 Cs-Sediment Hillslope Model, Ava D. Simms, Colin D. Woodroffe, Brian G. Jones, Henk Heijnis, Jennifer Harrison, Rob Mann
B. G. Jones
Soil redistribution studies are important, especially in water supply catchments, because the rate at which denudation is occurring has implications for offsite water quality. However, the extent to which soil is redistributed within the landscape can be difficult to determine. This challenge can be overcome using fallout caesium-137 (137Cs). This paper describes the rates of soil loss and remobilisation in two sub-catchments within the Sydney Basin region, namely Kembla and Kentish Creeks, which drain to the Cordeaux reservoir. The total inventories of 137Cs in catchment soils were determined, a 137Cs-regression equation and a theoretical diffusion and migration model were used …
Investigation Of Large-Scale Washover Of A Small Barrier System On The Southeast Australian Coast Using Ground Penetrating Radar, Brian G. Jones, C Bristow, Adam D. Switzer
Investigation Of Large-Scale Washover Of A Small Barrier System On The Southeast Australian Coast Using Ground Penetrating Radar, Brian G. Jones, C Bristow, Adam D. Switzer
B. G. Jones
Prehistoric depositional signatures for large-scale washover involving marine inundation events such as storm and tsunami have been the subject of considerable research over the last 15 years. Much of this research has focused on the identification of sand sheets in back-barrier environments as depositional records for extreme washover events. All these deposits must have a sediment source, and by their nature, the most likely source of sediment for washover into back-barrier environments is the barrier itself. This study identifies an erosional signature for large-scale washover from a small coastal barrier on the southeast Australian coast. A distinct lense of marine …
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
B. G. Jones
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 …
Response Of Coral Reefs To Climate Change: Expansion And Demise Of The Southernmost Pacific Coral Reef, Colin D. Woodroffe, Brendan P. Brooke, Michelle Linklater, David M. Kennedy, Brian G. Jones, Cameron Buchanan, Richard Mleczko, Quan Hua, Jian-Xin Zhao
Response Of Coral Reefs To Climate Change: Expansion And Demise Of The Southernmost Pacific Coral Reef, Colin D. Woodroffe, Brendan P. Brooke, Michelle Linklater, David M. Kennedy, Brian G. Jones, Cameron Buchanan, Richard Mleczko, Quan Hua, Jian-Xin Zhao
B. G. Jones
Coral reefs track sea level and are particularly sensitive to changes in climate. Reefs are threatened by global warming, with many experiencing increased coral bleaching. Warmer sea surface temperatures might enable reef expansion into mid latitudes. Here we report multibeam sonar and coring that reveal an extensive relict coral reef around Lord Howe Island, which is fringed by the southernmost reef in the Pacific Ocean. The relict reef, in water depths of 25-50 m, flourished in early Holocene and covered an area more than 20 times larger than the modern reef. Radiocarbon and uranium-series dating indicates that corals grew between …
Continental Aridification And The Vanishing Of Australia's Megalakes, Timothy J. Cohen, Gerald C. Nanson, John D. Jansen, B. G. Jones, Zenobia Jacobs, P Treble, David M. Price, Jan-Hendrik May, A Smith, Linda K. Ayliffe, John C. Hellstrom
Continental Aridification And The Vanishing Of Australia's Megalakes, Timothy J. Cohen, Gerald C. Nanson, John D. Jansen, B. G. Jones, Zenobia Jacobs, P Treble, David M. Price, Jan-Hendrik May, A Smith, Linda K. Ayliffe, John C. Hellstrom
B. G. Jones
The nature of the Australian climate at about the time of rapid megafaunal extinctions and humans arriving in Australia is poorly understood and is an important element in the contentious debate as to whether humans or climate caused the extinctions. Here we present a new paleoshoreline chronology that extends over the past 100 k.y. for Lake Mega-Frome, the coalescence of Lakes Frome, Blanche, Callabonna and Gregory, in the southern latitudes of central Australia. We show that Lake Mega-Frome was connected for the last time to adjacent Lake Eyre at 50-47 ka, forming the largest remaining interconnected system of paleolakes on …
Alluvial Evidence For Major Climate And Flow Regime Changes During The Middle And Late Quaternary For Eastern Central Australia, Gerald C. Nanson, David M. Price, B. G. Jones, Jerry C. Maroulis, Maria Coleman, Hugo Bowman, Timothy J. Cohen, Tim Pietsch, Joshua R. Larsen
Alluvial Evidence For Major Climate And Flow Regime Changes During The Middle And Late Quaternary For Eastern Central Australia, Gerald C. Nanson, David M. Price, B. G. Jones, Jerry C. Maroulis, Maria Coleman, Hugo Bowman, Timothy J. Cohen, Tim Pietsch, Joshua R. Larsen
B. G. Jones
As a low-gradient arid region spanning the tropics to the temperate zone, the Lake Eyre basin has undergone gentle late Cenozoic crustal warping leading to substantial alluvial deposition, thereby forming repositories of evidence for palaeoclimatic and palaeohydrological changes from the Late Tertiary to the Holocene. Auger holes and bank exposures at five locations along the lower 500 km of Cooper Creek, a major contributor to Lake Eyre in the eastern part of the basin, yielded 85 luminescence dates (TL and OSL) that, combined wit a further 142 luminescence dates from northeastern Australia, have established a chronology of multiple episodes of …
Attachment Of Molecular Hydrogen To An Isolated Boron Cation: An Infrared And Ab Initio Study, Viktoras Dryza, Berwyck L. J Poad, Evan J. Bieske
Attachment Of Molecular Hydrogen To An Isolated Boron Cation: An Infrared And Ab Initio Study, Viktoras Dryza, Berwyck L. J Poad, Evan J. Bieske
Berwyck L. J. Poad
Structural properties of the B+−H2 electrostatic complex are investigated through its rotationally resolved infrared spectrum in the H−H stretch region (3905−3975 cm−1). The spectrum, which was obtained by monitoring B+ photofragments while the IR wavelength was scanned, is consistent with the complex having a T-shaped structure and a vibrationally averaged intermolecular separation of 2.26 Å, which decreases by 0.04 Å when the H2 subunit is vibrationally excited. The H−H stretch transition of B+−H2 is red-shifted by 220.6 ± 1.5 cm−1 from that of the free H2 molecule, much more than for other dihydrogen complexes with comparable binding energies. Properties of …
Interactions Between The Chloride Anion And Aromatic Molecules: Infrared Spectra Of The Cl-_C6h5ch3, Cl-_C6h5nh2 And Cl-_C6h5oh Complexes, Corinna Emmeluth, Berwyck L. J Poad, Christopher D. Thompson, Evan J. Bieske
Interactions Between The Chloride Anion And Aromatic Molecules: Infrared Spectra Of The Cl-_C6h5ch3, Cl-_C6h5nh2 And Cl-_C6h5oh Complexes, Corinna Emmeluth, Berwyck L. J Poad, Christopher D. Thompson, Evan J. Bieske
Berwyck L. J. Poad
The Cl-−C6H5CH3·Ar, Cl-−C6H5NH2·Ar, and Cl-−C6H5OH·Ar anion complexes are investigated using infrared photodissociation spectroscopy and ab initio calculations at the MP2/aug-cc-pVDZ level. The results indicate that for Cl-−C6H5NH2 and Cl-−C6H5OH, the Cl- anion is attached to the substituent group by a single near-linear hydrogen bond. For Cl-−C6H5CH3, the Cl- is attached to an ortho-hydrogen atom on the aromatic ring and to a hydrogen atom on the methyl group by a weaker hydrogen bond. The principal spectroscopic consequence of the hydrogen-bonding interaction in the three complexes is a red-shift and intensity increase for the CH, NH, and OH stretching modes. Complexities in …
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 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, …
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 …
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 …
Continental Aridification And The Vanishing Of Australia's Megalakes, Timothy J. Cohen, Gerald C. Nanson, John D. Jansen, B. G. Jones, Zenobia Jacobs, P Treble, David M. Price, Jan-Hendrik May, A Smith, Linda K. Ayliffe, John C. Hellstrom
Continental Aridification And The Vanishing Of Australia's Megalakes, Timothy J. Cohen, Gerald C. Nanson, John D. Jansen, B. G. Jones, Zenobia Jacobs, P Treble, David M. Price, Jan-Hendrik May, A Smith, Linda K. Ayliffe, John C. Hellstrom
Timothy Cohen
The nature of the Australian climate at about the time of rapid megafaunal extinctions and humans arriving in Australia is poorly understood and is an important element in the contentious debate as to whether humans or climate caused the extinctions. Here we present a new paleoshoreline chronology that extends over the past 100 k.y. for Lake Mega-Frome, the coalescence of Lakes Frome, Blanche, Callabonna and Gregory, in the southern latitudes of central Australia. We show that Lake Mega-Frome was connected for the last time to adjacent Lake Eyre at 50-47 ka, forming the largest remaining interconnected system of paleolakes on …