Laboratory Kinetic Studies of the Reactions of Cl Atoms with Species of Biogenic Origin: δ3-Carene, Isoprene, Methacrolein and Methyl Vinyl Ketone     

Carlos E. Canosa-Mas  Hilary R. Hutton-Squire  Martin D. King  David J. Stewart  Katherine C. Thompson  Richard P. Wayne 《Journal of Atmospheric Chemistry》1999,34(1):163-170

The rate coefficients for the reaction between atomic chlorine and a number of naturally occurring species have been measured at ambient temperature and atmospheric pressure using the relative rate technique. The values obtained were (4.0 ± 0.8) × 10^-10, (2.1 ± 0.5) × 10^-10, (3.2 ± 0.5) × 10^-10, and (4.9 ± 0.5) × 10^-10 cm³ molecule^-1 s^-1, for reactions with isoprene, methyl vinyl ketone, methacrolein and ³-carene, respectively. The value obtained for isoprene compares favourably with previously reported values. No values have been reported to date for the rate constants of the other reactions.  相似文献   

The Kråkenes late-glacial palaeoenvironmental project   总被引：1，自引：0，他引：1  

Hilary H. Birks  R. W. Battarbee  D. J. Beerling  H. J. B. Birks  S. J. Brooks  C. A. Duigan  S. Gulliksen  H. Haflidason  F. Hauge  V. J. Jones  B. Jonsgard  M. Kårevik  E. Larsen  G. Lemdahl  R. Løvlie  J. Mangerud  S. M. Peglar  G. Possnert  J. P. Smol  J. O. Solem  I. Solhøy  T. Solhøy  E. Sønstegaard  H. E. Wright 《Journal of Paleolimnology》1996,15(3):281-286

Kråkenes is the site of a small lake on the west coast of Norway that contains a long sequence of late-glacial sediments. The Younger Dryas is well represented, as a cirque glacier developed in the catchment at this time. This site offers unique opportunities to reconstruct late-glacial environments from independent sources of evidence; physical evidence (glacial geomorphology, sedimentology, palaeomagnetism, radiocarbon dating), and biological evidence from the remains of animals and plants derived from both the terrestrial and aquatic ecosystems. This report describes the background to the site, and the international multidisciplinary project to reconstruct late-glacial and early Holocene environmental and climatic changes at Kråkenes.  相似文献   

Evidence from polymict ureilite meteorites for a disrupted and re-accreted single ureilite parent asteroid gardened by several distinct impactors     

Hilary Downes  David W. Mittlefehldt  John W. Valley 《Geochimica et cosmochimica acta》2008,72(19):4825-4844

Ureilites are ultramafic achondrites that exhibit heterogeneity in mg# and oxygen isotope ratios between different meteorites. Polymict ureilites represent near-surface material of the ureilite parent asteroid(s). Electron microprobe analyses of >500 olivine and pyroxene clasts in several polymict ureilites reveal a statistically identical range of compositions to that shown by unbrecciated ureilites, suggesting derivation from a single parent asteroid. Many ureilitic clasts have identical compositions to the anomalously high Mn/Mg olivines and pyroxenes from the Hughes 009 unbrecciated ureilite (here termed the “Hughes cluster”). Some polymict samples also contain lithic clasts derived from oxidized impactors. The presence of several common distinctive lithologies within polymict ureilites is additional evidence that ureilites were derived from a single parent asteroid.In situ oxygen three isotope analyses were made on individual ureilite minerals and lithic clasts, using a secondary ion mass spectrometer (SIMS) with precision typically better than 0.2-0.4‰ (2SD) for δ¹⁸O and δ¹⁷O. Oxygen isotope ratios of ureilitic clasts fall on a narrow trend along the CCAM line, covering the range for unbrecciated ureilites, and show a good anti-correlation with mineral mg#. SIMS analysis identifies one ferroan lithic clast as an R-chondrite, while a second ferroan clast is unlike any known meteorite. An exotic enstatite grain is derived from an enstatite chondrite or aubrite, and another pyroxene grain with Δ¹⁷O of −0.4 ± 0.2‰ is unrelated to any known meteorite type.Ureilitic olivine clasts with mg#s < 85 are much more common than those with mg# > 85 which include the melt-inclusion-bearing “Hughes cluster” ureilites. Thus melt was present in regions of the parent ureilite asteroid with a bulk mg# > 85 when the asteroid was disrupted by impact, giving rise to two types of ureilites: common ferroan ones that were residual after melting and less common magnesian ones that were still partially molten when disruption occurred. One or more daughter asteroids re-accreted from the remnants of the mantle of the proto-ureilite asteroid. Polymict ureilite meteorites represent regolith that subsequently formed on the surface of a daughter asteroid, including impact-derived material from at least six different meteoritic sources.  相似文献   

My life with macrofossils     

Hilary H. Birks 《Journal of Paleolimnology》2017,57(2):181-200

  相似文献   

Potential Impacts of Climate Change on Tropical Asian Forests Through an Influence on Phenology   总被引：3，自引：0，他引：3  

Richard T. Corlett  James V. Lafrankie Jr. 《Climatic change》1998,39(2-3):439-453

Changes in plant phenology will be one of the earliest responses to rapid global climate change and could potentially have serious consequences both for plants and for animals that depend on periodically available plant resources. Phenological patterns are most diverse and least understood in the tropics. In those parts of tropical Asia where low temperature or drought impose a seasonal rest period, regular annual cycles of growth and reproduction predominate at the individual, population, and community level. In aseasonal areas, individuals and populations show a range of sub- to supra-annual periodicities, with an overall supra-annual reproductive periodicity at the community level. There is no evidence for photoperiod control of phenology in the Asian tropics, and seasonal changes in temperature are a likely factor only near the northern margins. An opportunistic response to water availability is the simplest explanation for most observed patterns where water is seasonally limiting, while the great diversity of phenological patterns in the aseasonal tropics suggests an equal diversity of controls. The robustness of current phenological patterns to high interannual and spatial variability suggests that most plant species will not be seriously affected by the phenological consequences alone of climate change. However, some individual plant species may suffer, and the consequences of changes in plant phenology for flower- and fruit-dependent animals in fragmented forests could be serious.  相似文献   

Book reviews     

Richard Le Heron  David Mercer  Richard T. Jackson  Hilary P. M. Winchester  Peter L. Simons  M. A. J. WilliamS 《The Australian geographer》1990,21(2):174-196

A WORLD IN CRISIS? Geographical Perspectives (second edition) edited by R. J. Johnston and P. J. Taylor. 15 x 23 cm, x and 371 pages. Basil Blackwell: Oxford 1989 (ISBN 0 631 16271 2) $A34.95 (soft).

INTEGRATED RURAL DEVELOPMENT PROGRAMMES IN PAPUA NEW GUINEA: External Aid and Provincial Planning (IASER Monograph No 28) by R. Crittenden and D. A. M. Lea, 17 x 24 cm, xv and 132 pages. Papua New Guinea Institute of Applied Social and Economic Research and Department of Geography and Planning, University of New England: Armidale 1989 (ISBN 9980 75 018 9).

ACCOMMODATING INEQUALITY: Gender and Housing by Sophie Watson. 14 x 21 cm, x and 157 pages. Allen & Unwin: Sydney 1988 (ISBN 0 04 320209 2) $A 14.95 (soft).

A SHORT HISTORY OF GEOMORPHOLOGY by K. J. Tinkler. 14 x 22 cm, xviii and 317 pages, Croom Helm: London 1985 (ISBN 0 7099 2441 0) $A49.95 (hard).

PATHWAYS IN GEOLOGY: Essays in Honour of

Edwin Sherbon Hills edited by R. W. Le Mai‐

tre. 25 x 19 cm, viii and 463 pages. Basil

Blackwell: Melbourne 1989 (ISBN

0731682416) $A110.00 (hard).

CHANGING THE FACE OF THE EARTH: Culture, Environment, History by I. G. Simmons. 17 x 24 cm, xiii and 487 pages. Basil Blackwell: Oxford 1989 (ISBN 0 631 16351 4) $A49.95 (soft).

PLANNED TO DEATH: The Annihilation of a Place Called Howdendyke by J. D. Porteous. 16 x 24 cm, xiii and 254 pages. Manchester University Press: Manchester 1989 (ISBN 0 7190 2831 0) £35.00 (hard).

A SOCIAL ATLAS OF DARWIN: 1986. Census of Population and Housing by J. Taylor and D.

Jaensch. 21 x 29 cm, and 66 pages. Australian Bureau of Statistics and North Australia Research Unit: Darwin 1989 (ISBN 0 642 143322 6).

ATLAS OF DEMOGRAPHIC CHANGE IN THE SOUTH EAST REGION OF NEW SOUTH WALES 1861–1991 by Terry G. Birtles and Jane E. Gordon. 21 x 29 cm, v and 141 pages. Canberra College of Advanced Education: Belconnen 1989 (ISBN 0 85889 355 5 $A40.00 (soft).

LABOUR ADJUSTMENT IN METROPOLITAN REGIONS by P. S. Morrison 15 x 21 cm, ix and 254 pages. Victoria University Press: Wellington 1989 (ISBN 0 86473 190 6) SA25.00 (soft).

AUSTRALIAN REGIONAL DEVELOPMENTS: Readings in Regional Experiences, Policies and Prospects (Australian Regional Developments No. 10) edited by B. Higgins and K. Zagorski. 17 x 25 cm. xi and 260 pages. AGPS Press: Canberra 1989 (ISBN 0 644 0935).

SOUTH AUSTRALIAN MANUFACTURING IN TRANSITION edited by T. J. Mules. 15 x 21 cm, vii and 188 pages. Wakefield Press (for Centre of South Australian Economic Studies): Adelaide 1989 (ISBN 909591 74 1) $A24.95 (soft).

COUNTERURBANIZATION: The Changing Pace’ and Nature of Population Deconcentration edited by A. G. Champion. 16 x 24 cm, xxii and 266 pages. Edward Arnold: London 1989 (ISBN 0 7131 6614 2) £27.00 (hard).

THE HUMANE CITY: Cities as if People Matter by J. R. Short. 15 x 22 cm, 167 pages. Basil Blackwell: Oxford 1989 (ISBN 0 631 15824 3) $A27.95 (soft).

THE TORRES STRAIT: People and History (revised edition) by J. Singe. 13 x 19 cm, xviii and 261 pages. University of Queensland Press: St Lucia 1989 (first published in 1979) (ISBN 0 7022 2232 1) $A19.95 (soft).

HAWKE'S LAW: The Politics of Mining and Aboriginal Land Rights in Australia by R. T. Libby. xxvii and 175 pages. University of Western Australia Press: Nedlands 1989 (ISBN 085564 301 1) $A25.00.

THE THIRD WORLD: States of Mind and Being edited by J. Norwine and A. Gonzales. 15 x 23 cm, xi and 275 pages. Unwin Hyman: Boston 1989 (ISBN 0 04 910121 8) $A39.95 (soft).

IRELAND: A Contemporary Geographical Perspective edited by R. W. G. Carter and A. J. Parker. 14 x 22 cm, xiv and 486 pages. Routledge: London 1989 (ISBN 0 415 00486 3) $A 120.00 (hard).  相似文献   

Determination of Incompatible Trace Elements in Mantle Clinopyroxenes by LA-ICP-MS: A Comparison of Analytical Performance with Established Techniques     

Paul R.D. Mason  Kym E. Jarvis  Hilary Downes  Riccardo Vannucci 《Geostandards and Geoanalytical Research》1999,23(2):157-172

Incompatible trace element abundances have been determined in mantle-derived clinopyroxenes by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) in a comparative study with established microanalytical and bulk techniques. Individual clinopyroxene grains were sampled for the laser ablation study from sieved mineral separate fractions, from which similar mineral grains had been previously extracted for microprobe (SIMS) and bulk (INAA and ID-TIMS) analysis. Mineral grains were ablated with variable degrees of surface spatial resolution (50-200 μm) in order to maximise ICP-MS analyte count rates and to improve detection limits. A comparison of results from the different techniques reveals that for the most homogeneous samples LA-ICP-MS can achieve excellent levels of agreement with other techniques (10%) and good precision for most of the studied elements (1-5% RSD). Variations in calculated concentrations by LA-ICP-MS confirm inter- and intra-mineral heterogeneity determined by SIMS, reflecting changes in sample composition and texture. The long-term reproducibility of the technique is shown by the consistency of results for one sample analysed on thirteen occasions over a period of nine months.  相似文献   

Interviews and Questionnaires as Mixed Methods in Population Geography: TheCase of Lone Fathers in Newcastle,Australia     

Hilary P.M. Winchester 《The Professional geographer》1999,51(1):60-67

A mixed method approach was adopted to study the experiences of lonefathers, using a classic triangulation approach of interview and questionnaire data. This study utilised an empirical realist framework of scientific enquiry, with the ‘soft’ individual interview data seen as an adjunct to the ‘hard’ aggregate quantitative methods. A review of this study found that the interviews worked well as a pilot study in a classic mixed methods framework. The questionnaires provided a range of information about thecharacteristics of this group of lone fathers, but it was the interviews which provided astonishing depth on the causes of marital breakdown and post-marital conflict, and on the discourses and other structures which sustain social processes. In this study, the interview techniques could have been used differently, in a different framework of analysis (that of critical rather than empirical realism) without the support of other mixed methods.  相似文献   

Five guidelines for selecting hydrological signatures          下载免费PDF全文

Hilary McMillan  Ida Westerberg  Flora Branger 《水文研究》2017,31(26):4757-4761

  相似文献   

Information content of snow hydrological signatures based on streamflow,precipitation and air temperature     

Ivan Horner  Flora Branger  Hilary McMillan  Olivier Vannier  Isabelle Braud 《水文研究》2020,34(12):2763-2779

Hydrological signatures that represent snow processes are valuable to gain insights into snow accumulation and snow melt dynamics. We investigated five snow signatures. Considering inter-annual average of each calendar day, two slopes derived from the relation between streamflow and air temperature for different periods and streamflow peak maxima are used as signatures. In addition, two different approaches are used to compute inter-annual average and yearly snow storage estimates. We evaluated the ability of these signatures to characterize average (a) snow melt dynamics and (b) snow storage. They were applied in 10 Critical Zone Observatory catchments of the Southern Sierra mountains (USA) characterized by a Mediterranean climate. The relevance and information content of the signatures are evaluated using snow depth and snow water equivalent measurements as well as inter-catchment differences in elevation. The slopes quantifying the relations between streamflow and air temperature and the date of streamflow peak were found to characterize snow melt dynamics in terms of snow melt rates and snow melt affected areas. Streamflow peak dates were linked to the period of highest snow melt rates. Snow storage could be estimated both on average, considering all years, and for each year. Snow accumulation dynamics could not be characterized due to the lack of streamflow response during the snow accumulation period. The signatures were found potentially valuable to gain insights into catchment scale snow processes. In particular, when comparing catchments or observed and simulated data, they could provide insights into differences in terms of (a) snow melt rate and/or snow melt affected area over the snow melt season and (b) average or yearly snow storage. Requiring only widely available data, these hydrological signatures can be valuable for snow processes characterization, catchment comparison/classification or model development, calibration or evaluation.  相似文献