21,299 research outputs found
Topics in Cement and Concrete Research
In recent decades, the construction sector has faced many changes. One of these changes is the shift in the role of national government from one-sided practices in which the government was solely responsible for strategic and long-term spatial planning to a multi-actor and multi-level arena. One outcome was a rearrangement of the balance between public and private responsibilities. This has led to new procurement routes and contracts as Private Finance Initiative (PFI) and Public Private Partnerships (PPP), as well as to a more performance-oriented client (both public and private). At the same time, construction firms changed their strategic focus from cost efficiency to adding value for money for the client, resulting in new contract forms such as Design & Construct (D&C), Building, Operate & Transfer (BOT) and variants there from. So far, governments of most European countries have their own restrictive specifications for the use of building materials
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Environmental regulation and competitiveness: Evidence from Romania
According to the pollution haven hypotheses differences in environmental regulation affect trade flows and plant location. Specifically, environmental stringency should decrease exports and increase imports of “dirty” goods. This paper estimates a gravity model to establish whether the
implementation of more stringent regulations in Romania has indeed affected its competitiveness and decreased exports towards its European trading partners. Our findings do not provide empirical support to the pollution haven hypothesis, i.e. environmental stringency is not found to
affect significantly total trade, or its components (pollution intensive trade and pollution intensive trade related to non-resource-based trade)
Multi-disciplinary Investigation of the Windows of John Thornton, focusing on the Great East Window of York Minster
Twenty-seven samples of glass from panel 2e of John Thornton’s Great East Window (1405–1408) at York Minster have been analyzed using energy dispersive x-ray analysis in the scanning electron microscope. This paper highlights our findings. Inserts and replacements of early modern and medieval glass have been identifi ed. White (colorless) and colored medieval glass differ significantly in composition, suggesting diff erent sources. Eleven samples of white glass original to the window are identical within analytical error, suggesting they came from the same batch, but the head of Christ is from another panel. Blue and flashed red glass were each the product of more than one batch of melting. Primarily, the condition of the glass is dependent upon silica content. Further investigations of other panels from the Great East Window, and of other windows by Thornton, are ongoing
Explaining Machine Learning Classifiers through Diverse Counterfactual Explanations
Post-hoc explanations of machine learning models are crucial for people to
understand and act on algorithmic predictions. An intriguing class of
explanations is through counterfactuals, hypothetical examples that show people
how to obtain a different prediction. We posit that effective counterfactual
explanations should satisfy two properties: feasibility of the counterfactual
actions given user context and constraints, and diversity among the
counterfactuals presented. To this end, we propose a framework for generating
and evaluating a diverse set of counterfactual explanations based on
determinantal point processes. To evaluate the actionability of
counterfactuals, we provide metrics that enable comparison of
counterfactual-based methods to other local explanation methods. We further
address necessary tradeoffs and point to causal implications in optimizing for
counterfactuals. Our experiments on four real-world datasets show that our
framework can generate a set of counterfactuals that are diverse and well
approximate local decision boundaries, outperforming prior approaches to
generating diverse counterfactuals. We provide an implementation of the
framework at https://github.com/microsoft/DiCE.Comment: 13 page
"Rapid and dramatic changes in vegetation" of a small pond on Holy Island (Northumbria): Chaotic dynamics?
This note describes changes to the relative extent of four structurally dominant submerged macrophytes in a pond on Holy Island National Nature Reserve, Northumbria, between 1991 and 1998. The estimated extent of the four submerged macrophytes and bare substratum between 1991 and 1998 showed dramatic changes with no obvious pattern or periodicity, as well as no identifiable natural or anthropogenic causes. Chaotic variation may be an important character of submerged pond plant populations, so that surveys taken in a single year may give an unreliable picture of plant populations
The geology of strata exposed in Roade railway cutting, Northamptonshire : engineering phase Priority 3 sections and overall assessment
This report describes the geology of the bedrock strata at the Roade railway cutting (a Site of
Special Scientific Interest), near Northampton, exposed by engineering works between 2006 and
2010 and made available to the BGS for detailed examination. Strata exposed previously during
engineering works between 2005 and 2006 (engineering phases Priority 1 & 2) are described in a
companion report (Barron and Woods, 2010). The exposed strata, totalling about 8 m in
thickness, belong entirely to the Blisworth Limestone Formation of the Great Oolite Group,
which is of Mid Jurassic age. Neither the base nor top of the formation are exposed. The current
report includes text descriptions and graphic sections of the localities examined, a plan of the
cutting showing locations and the distribution of the strata with correlations, close-up
photographs of the bedrock exposed, and photographic panoramas of the cutting sides. It also
includes an assessment of the exposed strata in terms of their sedimentary facies and lateral
variability
Forest Return on an Abandoned Field - Secondary Succession Under Monitored Conditions
The secondary succession pattern observed on an arable field abandoned since 1974 in Tilio-Carpinetum habitat is described and disscussed. Results obtained during 36 years of study confirm that succession on an abandoned field leads from a typical segetal community to the formation of a juvenile treestand composed of pioneer species. Our study supports the view that succession is a process which is largely dependent on the initial conditions and surrounding vegetation. The results indicate that some species can modify the course of this process, accelerating or slowing it down. Limitations of the method and prognosis of future vegetation development are also discussed
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