Exploring Landcare Effectiveness Using Organisational Theory     

Allan Curtis  Marike Van Nouhuys  Wayne Robinson  Jacinta MacKay 《The Australian geographer》2000,31(3):349-366

Landcare is an important example of the potential of state-sponsored participation to establish viable local organisations and contribute to rural development. In this paper, the authors discuss their research using organisational theory to explore Landcare effectiveness. Data were obtained from a mailed survey to Landcare groups in the state of Victoria during 1998. Levels of group activity were used as a surrogate measure of group effectiveness. Groups were ranked according to their level of activity to assess the impact of factors likely to affect group performance, the efficacy of program logic, and the extent groups were contributing to program goals. Survey data suggested key aspects of Landcare Program logic were sound. Examination of the membership and activity profiles of groups suggested 90 per cent of the respondent groups were making a worthwhile contribution to program goals. This research also confirmed the importance of factors identified by others as significant influences on organisational effectiveness: the importance of having clear goals, objectives and plans; resource availability; facilitation by an outside agency; access to a funded group co-ordinator; and communication between stakeholders. Unfortunately, there are critical, ongoing management issues surrounding many of these topics.  相似文献   

GGR Biennial Critical Review: Analytical Developments Since 2010     

Michael Wiedenbeck  Roxana Bugoi  M. John M. Duke  Tibor Dunai  Jacinta Enzweiler  Mary Horan  Klaus Peter Jochum  Kathryn Linge  Jan Košler  Silke Merchel  Luiz F.G. Morales  Lutz Nasdala  Roland Stalder  Paul Sylvester  Ulrike Weis  Arnaud Zoubir 《Geostandards and Geoanalytical Research》2012,36(4):337-398

Advances in the chemical and isotopic characterisation of geological and environmental materials can often be ascribed to technological improvements in analytical hardware. Equally, the creation of novel methods of data acquisition and interpretation, including access to better reference materials, can also be crucial components enabling important breakthroughs. This biennial review highlights key advances in either instrumentation or data acquisition and treatment, which have appeared since January 2010. This review is based on the assessments by scientists prominent in each of the given analytical fields; it is not intended as an exhaustive summary, but rather provides insight from experts of the most significant advances and trends in their given field of expertise. In contrast to earlier reviews, this presentation has been formulated into a unified work, providing a single source covering a broad spectrum of geoanalytical techniques. Additionally, some themes that were not previously emphasised, in particular thermal ionisation mass spectrometry, accelerator‐based methods and vibrational spectroscopy, are also presented in detail.  相似文献   

Classical and New Procedures of Whole Rock Dissolution for Trace Element Determination by ICP‐MS     

Aloísio J. B. Cotta  Jacinta Enzweiler 《Geostandards and Geoanalytical Research》2012,36(1):27-50

Sample digestion is a critical stage in the process of chemical analysis of geological materials by ICP‐MS. We present a new HF/HNO₃ procedure to dissolve silicate rock samples using a high pressure asher system. The formation of insoluble AlF₃ was the major obstacle in achieving full recoveries. This was overcome by setting an appropriate digestion temperature and adding Mg to the samples before digestion. Sodium peroxide sintering was also investigated and the inclusion of a heating step to the alkaline sinter solution improved the recoveries of thirteen elements other than the lanthanides. The results of these procedures were compared with data sets generated by common acid decomposition techniques. Forty‐one trace elements were determined using an ICP‐QMS equipped with a collision cell. Under optimum conditions of gas flow and kinetic energy discrimination, polyatomic interferences were eliminated or attenuated. The measurement bias obtained for eight reference materials (BCR‐2, BHVO‐2, BIR‐1, BRP‐1, OU‐6, GSP‐2, GSR‐1 and RGM‐1) and intermediate precision (RSD) were generally better than ± 5%. The expanded measurement uncertainties estimated for two certified reference materials were mostly between 7 and 15%. New data sets for the reference materials are provided, including constituents with previously unavailable values and also for the USGS candidate reference material G‐3.  相似文献   

Determination of Cr,Cu, Ni,Sn, Sr and Zn Mass Fractions in Geochemical Reference Materials by Isotope Dilution ICP‐MS     

Aloísio J.B. Cotta  Jacinta Enzweiler 《Geostandards and Geoanalytical Research》2013,37(1):35-50

Isotope dilution (ID) mass spectrometry is a primary method of analysis suited for the accurate and precise measurement of several trace elements in geological matrices. Here we present mass fractions and respective uncertainties for Cr, Cu, Ni, Sn, Sr and Zn in 10 silicate rock reference materials (BCR‐2, BRP‐1, BIR‐1, OU‐6, GSP‐2, GSR‐1, AGV‐1, RGM‐1, RGM‐2 and G‐3) obtained by the double ID technique and measuring the isotope ratios with an inductively coupled plasma‐mass spectrometer equipped with collision cell. Test portions of the samples were dissolved by validated procedures, and no further matrix separation was applied. Addition of spikes was designed to achieve isotope ratios close to unity to minimise error magnification factors, according to the ID theory. Radiogenic ingrowth of ⁸⁷Sr from the decay of ⁸⁷Rb was considered in the calculation of Sr mass fractions. The mean values of our results mostly agree with reference values, considering both uncertainties at the 95% confidence level, and also with ID data published for AGV‐1. Considering all results, the means of the combined uncertainties were < 1% for Sr, approximately 2% for Sn and Cu, 4% for Cr and Ni and almost 6% for Zn.  相似文献   

GGR Critical Review of Analytical Developments in 2008–2009: An Introduction     

Janet M. Hergt  Ricardo Arevalo Jr  L. Paul Bèdard  Jeremy Bellucci  Jacinta Enzweiler  Klaus Peter Jochum  Kathryn L. Linge  William F. McDonough  Regina Mertz-Kraus  Michael Wiedenbeck  Xiaohong Wang  Jon D. Woodhead 《Geostandards and Geoanalytical Research》2010,34(4):325-326

This collection of articles represents the fourth in a series of reviews in which authors have aimed at capturing the key advances in a range of analytical fields ( Hergt et al. 2005, 2006, 2008 ). The publication period under review is 2008–2009 and the intention here is to provide readers with a summary of the most influential developments published during this period, across a broad range of topics appropriate to the Earth and environmental sciences. Most authors comment on the ways in which the emphases of research in their specific fields of examination have changed over time. All note an increase in rigour and focus on data quality. Whether advances have taken place in instrumentation, sample manipulation or data deconvolution, there are a large number of dedicated scientists out there contributing to the high quality of geochemical data employed in geological and environmental research.  相似文献   

Platinum-Group Elements and Gold Determination in NiS Fire Assay Buttons by UV Laser Ablation ICP-MS     

Alexandre P.de S. Jorge  Jacinta Enzweiler  Elisa K. Shibuya  Jorge E.S. Sarkis  Ana Maria G. Figueiredo 《Geostandards and Geoanalytical Research》1998,22(1):47-55

The direct analysis of nickel sulfide fire assay buttons by UV laser ablation ICP-MS was used to determine the platinum-group elements and gold in the following reference materials: UMT-1, WPR-1, WMG-1, GPt-4, GPt-6 and CHR-Bkg. The instrument was calibrated with buttons prepared using quartz doped with the appropriate standard solutions. Analytical precision (RSD) was generally better than 10%, although occasional higher RSDs may infer local heterogeneities within nickel sulfide buttons. Good or excellent agreement was observed between analysed and reference material values except Rh in UMT-1 and WMG-1, which suffered an interference from copper. Detection limits calculated as 10 s quantitation limits were Au (1.7 ng g⁻¹), Pd (3.3 ng g⁻¹), Pt (8.3 ng g⁻¹), Os (1.3 ng g⁻¹), Rh (1 ng g⁻¹), Ru (5 ng g⁻¹) and Ir (0.7 ng g⁻¹).  相似文献   

Population vulnerability to tsunami hazards informed by previous and projected disasters: a case study of American Samoa     

Wood  Nathan  Jones  Jeanne M.  Yamazaki  Yoshiki  Cheung  Kwok-Fai  Brown  Jacinta  Jones  Jamie L.  Abdollahian  Nina 《Natural Hazards》2019,95(3):505-528

Natural Hazards - Population vulnerability from tsunamis is a function of the number and location of individuals in hazard zones and their ability to reach safety before wave arrival. Previous...  相似文献   

Assessment of Dissolution of Silicate Rock Reference Materials with Ammonium Bifluoride and Nitric Acid in a Microwave Oven   总被引：1，自引：0，他引：1  

Thais T. Magaldi  Margareth S. Navarro  Jacinta Enzweiler 《Geostandards and Geoanalytical Research》2019,43(1):189-208

The complete dissolution of representative test portions of powdered rock samples for the determination of the mass fractions of trace elements by ICP‐MS relies either on aggressive and time‐consuming acid digestions or fusion/sintering with appropriate fluxes. Here, we evaluate a microwave oven dissolution method that employs a solution of NH₄HF₂ and HNO₃. The entire procedure occurs in a closed vessel system and takes up to 4 h. In hundreds of digestions, the precipitation of fluorides was never observed. Replicate decomposition of 100 mg of twenty‐one international reference materials (RMs) of igneous rocks, and also one of a shale presented mostly satisfactory recoveries of forty‐one trace elements. Important exceptions were Zr and Hf in G‐2 and GSP‐2 (mean recoveries of ca. 70%), although for four other felsic rock RMs, the digestion was complete. For ultramafic rock RMs, we present Cr results that indicate quantitative dissolution of Cr‐bearing phases. We discuss the findings and conclude that advances in sample preparation of geological materials for instrumental analysis would benefit from a better understanding of how specific characteristics, such as composition and crystallinity of certain minerals, may affect their reactivity.  相似文献   

激光剥蚀-等离子体质谱技术及其在地球化学宇宙化学和环境研究中的应用   总被引：1，自引：0，他引：1  

JOCHUM Klaus Peter  STOLL Brigitte  FRIEDRICH Jon M  AMINI Marghaleray  BECKER Stefan  DüCKING Marc  EBEL Denton S  ENZWEILER Jacinta  胡明月  KUZMIN Dmitry  MERTZ KRAUS Regina  MüLLER Werner E G  REGNERY Julia  SOBOLEV Alexander  王晓红  詹秀春 《岩矿测试》2009,28(1):53-68

激光剥蚀-等离子体质谱(LA-ICPMS)已成为地球化学、宇宙化学和环境研究领域元素和同位素原位分析最重要的技术之一。文章介绍了多种类型的质谱仪及其使用的激光器。用途最广的LA-ICPMS仪器之一是单接收器扇形磁场质谱仪,配有Nd:YAG激光剥蚀系统(激光波长分为193 nm和213 nm两种),MPI Mainz实验室使用的就是这套系统,文章对此作一详细介绍。文中阐述了数据优化技术及其多种校正过程;介绍LA-ICPMS在痕量元素和同位素分析领域的一些应用,包括参考物质的研制,Hawaiian玄武岩、Martian陨石、生物骨针和珊瑚虫中痕量元素分析及熔融包裹体和富钙-铝碳质球粒陨石中的铅和锶同位素测量。  相似文献   

Routine Control of Accuracy in Silicate Rock Analysis by X-Ray Fluorescence Spectrometry     

Maria Aparecida Vendemiatto  Jacinta Enzweiler 《Geostandards and Geoanalytical Research》2001,25(2-3):283-291

In this study, we used the modified Horwitz expression (H_c= 0.01c^0.8495, which gives the precision as a function of concentration) to evaluate and control the accuracy of results of silicate rock analysis obtained by X-ray fluorescence spectrometry. This expression is currently used by the organisers of the GeoPT international proficiency tests, to assign the precision limits of each analyte and subsequently to evaluate the data provided by laboratories whose main application is geochemistry. Results for major and trace elements, determined in glass disk and pressed pellets, respectively, were evaluated. Nine international silicate rock reference materials were analysed and results were compared to the recommended values plus and minus the limits given by the above expression. Those limits are easily attained for most major elements, but not for trace elements. Sample preparation and sub-sampling contributions to precision were evaluated by analysis of an in-house reference sample. In our results, precision does not follow the Horwitz expression relationship with concentration. It is known that the final accuracy in XRF analysis depends strongly on instrumental settings and on the uncertainties associated with the certified or recommended values of the reference materials used to calibrate the spectrometer, but our results indicate that the precision expression can be useful, especially to inspect and correct calibration curves and to check routine instrumental accuracy.  相似文献