Soft X-ray reflectivity: from quasi-perfect mirrors to accelerator walls

Reflection of light from surfaces is a very common, but complex phenomenon not only in science and technology, but in every day life. The underlying basic optical principles have been developed within the last five centuries using visible light available from the sun or other laboratory light sources. X-rays were detected in 1895, and the full potential of soft- and hard-x ray radiation as a probe for the electronic and geometric properties of matter, for material analysis and its characterisation is available only since the advent of synchrotron radiation sources some 50 years ago. On the other hand high-brilliance and high power synchrotron radiation of present-days 3rd and 4th generation light sources is not always beneficial. Highenergy machines and accelerator-based light sources can suffer from a serious performance drop or limitations due to interaction of the synchrotron radiation with the accelerator walls, thus producing clouds of photoelectrons (e-cloud) which in turn interact with the accelerated beam. Thus the suitable choice of accelerator materials and their surface coating, which determines the x-ray optical behaviour is of utmost importance to achieve ultimate emittance. Basic optical principles and examples on reflectivity for selected materials are given here.Comment: 11 pages, contribution to the Joint INFN-CERN-EuCARD-AccNet Workshop on Electron-Cloud Effects: ECLOUD'12; 5-9 Jun 2012, La Biodola, Isola d'Elba, Italy; CERN Yellow Report CERN-2013-002, pp.105-11

The Relational Economics of Commercial Contract

Modern contract law scholarship embraces a particularly strange contradiction. On one hand, most legal scholars accept the core insight of what is called relational contract theory: most commercial contracts involve repeat players who seek to maximize wealth while still maintaining cooperative relationships. On the other hand, many of these same contract scholars believe that there is nothing contract law could or should do about it. They contend that contract law and legal theory are better off ignoring this insight, rather than trying to respond to it. . . . . This Article brings these disparate lines of contract scholarship together by introducing new information that could dramatically change how legal scholars make sense of relational contract theory. It turns out that while legal scholars have largely discounted the importance of relational contract theory, another community of scholars—working in organizational theory, marketing, and strategic management—have studied, tested, and developed its insights. As a result, they have not only empirically confirmed the presence of relational behaviors in modern contracting, but they have begun to discover the sort of data that might make it possible to better account for the economic effects of relational contracting behavior in both legal theory and contract law doctrine. This literature demonstrates that it is possible to operationalize the insights of relational contract theory in an interdisciplinary way that respects both the need for a methodologically rigorous framework and the complex nature of economic behavior. In this Article, I argue that contract law scholars should set out on that same course

The Relational Economics of Commercial Contract

Modern contract law scholarship embraces a particularly strange contradiction. On one hand, most legal scholars accept the core insight of what is called relational contract theory: most commercial contracts involve repeat players who seek to maximize wealth while still maintaining cooperative relationships. On the other hand, many of these same contract scholars believe that there is nothing contract law could or should do about it. They contend that contract law and legal theory are better off ignoring this insight, rather than trying to respond to it. . . . . This Article brings these disparate lines of contract scholarship together by introducing new information that could dramatically change how legal scholars make sense of relational contract theory. It turns out that while legal scholars have largely discounted the importance of relational contract theory, another community of scholars—working in organizational theory, marketing, and strategic management—have studied, tested, and developed its insights. As a result, they have not only empirically confirmed the presence of relational behaviors in modern contracting, but they have begun to discover the sort of data that might make it possible to better account for the economic effects of relational contracting behavior in both legal theory and contract law doctrine. This literature demonstrates that it is possible to operationalize the insights of relational contract theory in an interdisciplinary way that respects both the need for a methodologically rigorous framework and the complex nature of economic behavior. In this Article, I argue that contract law scholars should set out on that same course

An Assessment of Carousel Value-Added Tax Fraud in The European Carbon Market

The literature on the European Union Emission Trading System (EU ETS) is by now very rich. Much is known about the efficiency, the effectiveness, and the environmental and distributional impacts of the EU ETS. Less, however, is known about the carousel value-added-tax (VAT) fraud phenomena in the European carbon market. This article evaluates the welfare effects of carousel VAT fraud in the EU ETS using a computable general equilibrium (CGE) analysis. According to our findings, if VAT fraud occurs in the EU ETS, the effects on welfare for the EU Member States are negative, with welfare loss significantly higher than the VAT fraud value. This article also discusses the reverse charge mechanism that EU Member States could adopt to reduce the VAT fraud phenomena in the European carbon market

High discharge rate characteristics of nickel-cadmium batteries for pulse load filtering

Several tests of specially fabricated nickel-cadmium batteries having circular disk type electrodes were considered. These batteries were evaluated as filter elements between a constant current power supply and a five hertz pulsed load demanding approximately twice the power supply current during the load on portion of the cycle. Short tests lasting 10,000 cycles were conducted at up to a 21 C rate and an equivalent energy density of over 40 Joules per pound. In addition, two batteries were subjected to 10 to the 7 charge/discharge cycles, one at a 6.5 C rate and the other at a 13 C rate. Assuming an electrode to battery weight ratio of 0.5, these tests represent an energy density of about 7 and 14 Joules per pound respectively. Energy density, efficiency, capacitance, average voltage, and available capacity were tracked during these tests. After 10 to the 7 cycles, capacity degradation was negligible for one battery and about 20% for the other. Cadmium electrode failure may be the factor limiting lifetime at extremely low depth of discharge cycling. The output was examined and a simple equivalent circuit was proposed

An adaptive stigmergy-based system for evaluating technological indicator dynamics in the context of smart specialization

Regional innovation is more and more considered an important enabler of welfare. It is no coincidence that the European Commission has started looking at regional peculiarities and dynamics, in order to focus Research and Innovation Strategies for Smart Specialization towards effective investment policies. In this context, this work aims to support policy makers in the analysis of innovation-relevant trends. We exploit a European database of the regional patent application to determine the dynamics of a set of technological innovation indicators. For this purpose, we design and develop a software system for assessing unfolding trends in such indicators. In contrast with conventional knowledge-based design, our approach is biologically-inspired and based on self-organization of information. This means that a functional structure, called track, appears and stays spontaneous at runtime when local dynamism in data occurs. A further prototyping of tracks allows a better distinction of the critical phenomena during unfolding events, with a better assessment of the progressing levels. The proposed mechanism works if structural parameters are correctly tuned for the given historical context. Determining such correct parameters is not a simple task since different indicators may have different dynamics. For this purpose, we adopt an adaptation mechanism based on differential evolution. The study includes the problem statement and its characterization in the literature, as well as the proposed solving approach, experimental setting and results.Comment: mail: [email protected]

Chemotherapy accelerates immune-senescence and functional impairments of Vδ2pos T cells in elderly patients affected by liver metastatic colorectal cancer.

Human (gamma delta) γδ T cells are unconventional innate-like lymphocytes displaying a broad array of anti-tumor activities with promising perspectives in cancer immunotherapy. In this context, Vδ2pos T cells represent the preferential target of several immunotherapy protocols against solid tumors. However, the impact of both aging and chemotherapy (CHT) on Vδ2pos T cells is still unknown. The present study evaluates with multi-parametric flow cytometry the frequencies, terminal differentiation, senescence and effector-functions of peripheral blood and tumor infiltrating Vδ2pos T cells purified from liver metastases (CLM) of patients affected by colorectal cancer (CRC) compared to those of sex- and age-matched healthy donors. The peripheral blood of CLM patients underwent CHT is characterized by decreased amounts of Vδ2pos T cells showing a relative increase of terminally-differentiated CD27neg/CD45RApos (TEMRA) cells. The enrichment of this latter subset is associated with an increased expression of the senescent marker CD57. The acquisition of CD57 on TEMRA Vδ2pos T cells is also coupled with impairments in cytotoxicity and production of TNF-α and IFN-γ. These features resemble the acquisition of an immune-senescent profile by Vδ2pos T cells from CLM patients that received CHT, a phenomenon that is also associated with the loss of the co-stimulatory marker CD28 and with the induced expression of CD16. The group of CLM patients underwent CHT and older than 60 years old showed higher frequencies of CD57pos and TEMRA Vδ2pos T cells. Similar results were found for tumor infiltrating Vδ2pos T cell subset purified from CLM specimens of patients treated with CHT. The toxicity of CHT regimens also affects the homeostasis of Vδ2pos T cells by inducing higher frequencies of circulating CD57pos TEMRA subset in CLM underwent CHT and younger than 60 years old. Taken together, our data demonstrate that the enrichment of senescent Vδ2pos T cells in CLM patients is not only induced by patients' aging but also by the toxicity of CHT that further accelerates the accumulation of CD57pos TEMRA cells highly dysfunctional in their anti-tumor activities. These results are important to both predict the clinical outcome of CLM and to optimize those protocols of cell cancer immunotherapy employing unconventional Vδ2pos T cells

Solving the scalarization issues of Advantage-based Reinforcement Learning algorithms

In this research, some of the issues that arise from the scalarization of the multi-objective optimization problem in the Advantage Actor–Critic (A2C) reinforcement learning algorithm are investigated. The paper shows how a naive scalarization can lead to gradients overlapping. Furthermore, the possibility that the entropy regularization term can be a source of uncontrolled noise is discussed. With respect to the above issues, a technique to avoid gradient overlapping is proposed, while keeping the same loss formulation. Moreover, a method to avoid the uncontrolled noise, by sampling the actions from distributions with a desired minimum entropy, is investigated. Pilot experiments have been carried out to show how the proposed method speeds up the training. The proposed approach can be applied to any Advantage-based Reinforcement Learning algorithm

Formal Derivation of Mesh Neural Networks with Their Forward-Only Gradient Propagation

This paper proposes the Mesh Neural Network (MNN), a novel architecture which allows neurons to be connected in any topology, to efficiently route information. In MNNs, information is propagated between neurons throughout a state transition function. State and error gradients are then directly computed from state updates without backward computation. The MNN architecture and the error propagation schema is formalized and derived in tensor algebra. The proposed computational model can fully supply a gradient descent process, and is potentially suitable for very large scale sparse NNs, due to its expressivity and training efficiency, with respect to NNs based on back-propagation and computational graphs