The origin of syngenite in black crusts on the limestone monument King's Gate (Belgrade Fortress,Serbia) – the role of agriculture fertiliser     

Vesna Matović  Suzana Erić  Aleksandar Kremenović  Philippe Colomban  Danica Srećković-Batoćanin  Nenad Matović 《Journal of Cultural Heritage》2012,13(2):175-186

Black crusts formed on limestone built into the King's Gate represent the most important process in stone deterioration that is occurring in this part of the monumental complex of the Belgrade Fortress (Serbia). Of special importance is the association of salts (namely gypsum and syngenite). Syngenite is a common secondary deposit on granite monuments and on medieval stained glass (i.e., on K-containing materials). However, its appearance over calcareous substrates is not apparent, particularly in cases where cement mortar was not used for bounding. The origins of the potassium and sulphate ions required for syngenite formation are related to meteoritic water, which penetrates the soil above the arch of King's Gate. Water dissolves some soil components and becomes enriched with various ions before coming into contact with the limestone blocks. Enriched water contains two times more K⁺ and SO₄^2? ions than pristine meteoritic water does. The source of the required ions is potassium-sulphate that is present in agricultural fertilisers that are used above the monument. The proposed mechanism for syngenite formation was additionally supported with laboratory experiment. The results of X-ray diffractometry and SEM-EDS analyses of limestone treated with potassium-sulphate solution and sulphuric acid suggest the possibility that the syngenite was formed over calcite:CaCO₃ + K₂SO₄ + H₂SO₄ → K₂Ca(SO₄)₂ H₂O + CO₂↑However, the complex mechanisms of gypsum and syngenite formation under natural conditions (variable concentration of potassium and sulphate ions, intermediates phases, temperature changes, humidity, the amount of disposable water etc.) do not exclude the possibility of syngenite formation over gypsum.  相似文献   

University decision making and prestige: An empirical study     

Philippe Cyrenne  Hugh Grant 《Economics of Education Review》2009

In this paper, we examine the factors that influence the reputation or prestige of universities. We first develop a model of university behaviour which indicates how the decisions made by university officials would be chosen in order to maximize their respective reputations. In doing so, we assume that reputation is enhanced by the quality of students produced, the caliber of research and the service provided to the community in terms of the provision of publicly funded education services. We argue that the relative weights placed on these intermediate outputs may vary by university type as well as the means of producing them. Using the results of the reputational survey – a ranking of the institution in terms of reputation – conducted as part of the Canadian magazine Maclean’s overall ranking exercise, we then estimate an Error Correction—Ordered Probit Model of the rankings of Canadian universities to determine the factors that influence the change in reputation or “prestige” of the university as viewed by the external community. We find evidence that the change in reputation of a university is based on what might be considered the appropriate “signals” that one might use in estimating the respective quality of the institution given the respective differences in mission.  相似文献   

Data-driven estimates of global nitrous oxide emissions from croplands     

Qihui Wang  Feng Zhou  Ziyin Shang  Philippe Ciais  Wilfried Winiwarter  Robert B Jackson  Francesco N Tubiello  Greet Janssens-Maenhout  Hanqin Tian  Xiaoqing Cui  Josep G Canadell  Shilong Piao  Shu Tao 《国家科学评论(英文版)》2020,7(2):441

Croplands are the single largest anthropogenic source of nitrous oxide (N₂O) globally, yet their estimates remain difficult to verify when using Tier 1 and 3 methods of the Intergovernmental Panel on Climate Change (IPCC). Here, we re-evaluate global cropland-N₂O emissions in 1961–2014, using N-rate-dependent emission factors (EFs) upscaled from 1206 field observations in 180 global distributed sites and high-resolution N inputs disaggregated from sub-national surveys covering 15593 administrative units. Our results confirm IPCC Tier 1 default EFs for upland crops in 1990–2014, but give a ∼15% lower EF in 1961–1989 and a ∼67% larger EF for paddy rice over the full period. Associated emissions (0.82 ± 0.34 Tg N yr^–1) are probably one-quarter lower than IPCC Tier 1 global inventories but close to Tier 3 estimates. The use of survey-based gridded N-input data contributes 58% of this emission reduction, the rest being explained by the use of observation-based non-linear EFs. We conclude that upscaling N₂O emissions from site-level observations to global croplands provides a new benchmark for constraining IPCC Tier 1 and 3 methods. The detailed spatial distribution of emission data is expected to inform advancement towards more realistic and effective mitigation pathways.  相似文献   

Human activities aggravate nitrogen-deposition pollution to inland water over China     

Yang Gao  Feng Zhou  Philippe Ciais  Chiyuan Miao  Tao Yang  Yanlong Jia  Xudong Zhou  Butterbach-Bahl Klaus  Tiantian Yang  Guirui Yu 《国家科学评论(英文版)》2020,7(2):430

In the past three decades, China has built more than 87 000 dams with a storage capacity of ≈6560 km³ and the total surface area of inland water has increased by 6672 km². Leaching of N from fertilized soils to rivers is the main source of N pollution in China, but the exposure of a growing inland water area to direct atmospheric N deposition and N leaching caused by N deposition on the terrestrial ecosystem, together with increased N deposition and decreased N flow, also tends to raise N concentrations in most inland waters. The contribution of this previously ignored source of  N deposition to freshwaters is estimated in this study, as well as mitigation strategies. The results show that the annual amounts of N depositions ranged from 4.9 to 16.6 kg · ha⁻¹ · yr⁻¹ in the 1990s to exceeding 20 kg · ha⁻¹ · yr⁻¹ in the 2010s over most of regions in China, so the total mass of ΔN (the net contribution of N deposition to the increase in N concentration) for lakes, rivers and reservoirs change from 122.26 Gg N · yr⁻¹ in the 1990s to 237.75 Gg N · yr⁻¹ in the 2010s. It is suggested that reducing the N deposition from various sources, shortening the water-retention time in dams and decreasing the degree of regulation for rivers are three main measures for preventing a continuous increase in the N-deposition pollution to inland water in China.  相似文献   

Pooling-based continuous evaluation of information retrieval systems     

Alberto Tonon  Gianluca Demartini  Philippe Cudré-Mauroux 《Information Retrieval》2015,18(5):445-472

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Philippe Agid and Jean Claude Tarondeau,L’Opéra de Paris: Gouverner une grande institution culturelle     

Philippe Ravanas 《Journal of Cultural Economics》2007,31(3):243-245

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The Tour de France and cycling's Belle Epoque     

Philippe Gaboriau 《国际体育史杂志》2013,30(2):57-78

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Wanted: a ‘Reviewer Effectiveness Index‘     

Philippe C. BAVEYE 《Learned Publishing》2012,25(3):232-234

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Competition Between Two International Organisations Proposing Two Different Types of Reform to the Same Country: a Tunisian example     

Philippe Soulez 《Compare》1982,12(1):19-27

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Entrepreneurial innovation: The importance of context     

Erkko Autio  Martin Kenney  Philippe Mustar  Don Siegel  Mike Wright 《Research Policy》2014

The purpose of this article and the special issue is to improve our understanding of the theoretical, managerial, and policy implications of entrepreneurial innovation. We accomplish this objective by examining the role of context in stimulating such activity, as well as its impact on the outcomes of entrepreneurial innovation. Our analysis begins by outlining an overarching framework for entrepreneurial innovation and context. With reference to this framework we then compare the attributes of national innovation systems, entrepreneurship and entrepreneurial innovation, and categorize contextual influences on entrepreneurial innovation. We then situate the papers presented in this special issue within this framework. We conclude by outlining an agenda for additional research on this topic, focusing on the relationships between contexts and entrepreneurial innovation and then discuss policy implications, focusing on how public and private actors can meet these challenges.  相似文献