CCD imaging instruments for planetary spacecraft applications

The development of new spacecraft camera systems to be used in conjunction with CCD sensors is reported. A brief overview of the science objectives and engineering constraints which influence the design of cameras for deep space is followed by a review of two current development programs, one leading to a line scan imager and the other to an area array frame camera. For each of these, a general description of the imager is given. It is evident that currently available CCDs fall short of requirements in some respects

Arabic and English News Coverage on aljazeera.net

The controversial Al Jazeera network, with its Arabic and English news websites, is an interesting object for comparative study. This study compares the\ud two language versions in terms of their layouts and the structural features, regional and thematic coverage, and ideological perspective reflected in the headlines of\ud news reports. Content analysis and critical discourse analysis revealed differences between the two versions for all aspects except for thematic coverage, indicating\ud systematic biases in coverage, alongside efforts to present ideological balance. \ud \ud <br />\ud <br />\ud \ud Le réseau Al Jazeera, avec ses sites d’information en arabe et en anglais\ud représente un objet intéressant pour une étude comparative. Cette étude compare les versions dans les deux langues, en ce qui concerne la présentation et les\ud caractéristiques structurelles, la couverture régionale et thématique, ainsi que la perspective idéologique telle qu’elle est reflétée par les grands titres. L’analyse du\ud contenu et l’analyse du discours révèlent des différences entre les deux versions sur tous les aspects, sauf pour la couverture thématique et pointent un biais\ud systématique pour les domaines couverts et des efforts pour assurer un équilibre idéologiqu

What Is Optimal Financial Regulation?

The financial system is regulated to achieve a wide variety of purposes. However, the objective that distinguishes financial regulation from other kinds is that of safeguarding the economy against systemic risk. Concerns regarding systemic risk focus largely on banks, which traditionally have been considered to have a special role in the economy. The safety nets that have been rigged to protect banks from systemic risk have succeeded in preventing banking panics, but at the cost of distorting incentives for risk taking. Regulators have a variety of options to correct this distortion, but none can be relied upon to produce an optimal solution. Technological and conceptual advances may be ameliorating the problem, nonetheless. Banks are becoming less special. The US is leading the way, but the trends are apparent in other industrial countries as well. The challenge facing regulators is to facilitate these advances and hasten the end of the special status of banks. Once banks have lost their special status, financial safety nets may be dismantled thus ending the distortions they create. Ultimately, regulation for prudential purposes may be completely unnecessary. The optimal regulation for safety and soundness purposes may be no regulation at all.

The Role of the Financial Sector in Economic Performance

What distinguished financial institutions from other firms is the relatively small share of real assets on their balance sheets. Thus, the direct impact of financial institutions on the real economy is relatively minor. The indirect impact of financial markets and institutions on economic performance is extraordinarily important. The financial sector mobilizes savings and allocates credit across space and time. It provides not only payment services, but also enables firms and households to cope with economic uncertainties by hedging, pooling, sharing and pricing risks. An efficient financial sector reduces the cost and risk of producing and trading goods and services and thus makes an important contribution to raising the standard of living. The authors begin their analysis by considering how an economy would perform without a financial sector and then proceed to introduce a simplified financial sector with direct financial transactions between savers and investors. Financial intermediaries are introduced which transform the direct obligations of investors into indirect obligations of financial intermediaries which have attributes that savers prefer. This approach emphasizes how the financial sector can improve both the quantity and quality of real investment and thereby increase income per capita. The authors then consider the role of government in supporting an efficient financial sector. However, the authors show that not all government intervention is beneficial. They demonstrate the potentially detrimental effects of regulation on both the financial structure and the real economy. They also emphasize the competitive forces that influence the ultimate impact of regulations. Technological trends in telecommunications and computation seem likely to increase the ease with which users and providers of financial services can circumvent burdensome regulations, according to the authors. This has led to calls for reduction in the overall restrictions on financial firms, as well as for international harmonization of regulations regarding safety and soundness, insider trading and taxation. The authors examine how to quantify the gains to the economy from improving the efficiency of the financial sector and the potential social gains and costs which may result from the formation of financial conglomerates. The authors then consider pressures for international harmonization of financial regulation, contrasting institutional regulation with functional regulation. The authors conclude that efficient financial markets require an infrastructure of laws, conventions and regulation. Most of all, an efficient financial system requires confidence. Confidence encourages investors to allocate their savings through financial markets and institutions rather than to buy non-productive assets as a store of value. The authors suggest that such confidence can be fostered by appropriate regulation of institutions and markets to ensure users of financial services that they will receive fair treatment. According to the authors, the challenge is to foster a static and dynamically efficient financial system while maintaining sufficient regulatory oversight to promote confidence in the safety and soundness of the financial system.

Health Risk, Income, and Employment-Based Health Insurance

While many believe that an individual’s health plays an important role in both their willingness and ability to obtain health insurance in the employment-based setting, relatively little agreement exists on the extent to which health status affects coverage rates, particularly for those with lower incomes. In this paper, we examine the relationship between health risk and the purchase of group health insurance and whether that relationship differs by a person’s income and whether they obtain coverage in the small, medium, or large group market. Using the panel component of the 1996-2002 Medical Expenditure Panel Survey (MEPS), we find that health risk is positively associated with private health insurance across the different markets, and that this positive relationship is stronger for low and middle income people, particularly in the large group market. Our results are consistent with the existence of adverse selection in the group market in the form of low rates of coverage among low risks due to an absence of risk rating of premiums. We conclude that pooled premiums for low risks, particularly those with low incomes, may represent a more important financial barrier to coverage in voluntary group insurance than high premiums for high risks.

Screening of Coulomb interactions in transition metals

We discuss different methods of calculation of the screened Coulomb interaction $U$ in transition metals and compare the constraint local-density approximation (LDA) with the GW approach. We clarify that they offer complementary methods of treating the screening and should serve for different purposes. In the GW method, the renormalization of bare on-site Coulomb interactions between 3d electrons occurs mainly through the screening by the same 3d electrons, treated in the random phase approximation (RPA). The basic difference of the constraint-LDA method is that it deals with the neutral processes, where the Coulomb interactions are additionally screened by the ``excited'' electron, since it continues to stay in the system. This is the main channel of screening by the itinerant ($4sp$) electrons, which is especially strong in the case of transition metals and missing in the GW approach, although the details of this screening may be affected by additional approximations, which typically supplement these two methods. The major drawback of the conventional constraint-LDA method is that it does not allow to treat the energy-dependence of $U$. We propose a promising approximation based on the combination of these two methods. First, we take into account the screening of Coulomb interactions in the 3d-electron-line bands located near the Fermi level by the states from the subspace being orthogonal to these bands, using the constraint-LDA methods. The obtained interactions are further renormalized within the bands near the Fermi level in RPA. This allows the energy-dependent screening by electrons near the Fermi level including the same 3d electrons.Comment: 25 pages, 5 figures, 2 table

Is query translation a distinct task from search?

INTRODUCTION The University of Sheffield participated in iCLEF 2002 using, as a test-bed, the prototype under development in the Clarity project. Clarity is an EU funded project aimed at developing a system for cross-language information retrieval for so-called low density languages, those with few translation resources. Currently translation between English and Finnish is supported; soon Swedish will be added and in the near future Latvian and Lithuanian. Clarity is being developed in a user-centred way with user involvement from the beginning. The design of the first user interface was based on current best practise, particular attention was paid to empirical evidence for a specific design choice. Six paper-based interface mock-ups representing important points in the cross-language search task were generated and presented for user assessment as a part of an extensive user study. The study (reported in Petrelli et al. 2002) was conducted to understand users and uses of cross-language information retrieval systems. Many different techniques were applied: contextual enquiry, interviews, questionnaires, informal evaluation of existing cross-language technology, and participatory design sessions with the interface mock-ups mentioned above. As a result, a user class profile was sketched and a long list of user requirements was compiled. As a followup, a redesign session took place and the new system was designed for users whoknow the language(s) they are searching (polyglots); • search for writing (journalists, translators business analysts); • have limited searching skills; • know the topic in advance or will learn/read on it while searching; • use many languages in the same search session and often swap between them. New system features were listed as important and the user interface was redesigned. Considering the result of the study the new interface allowed the user to dynamically change the language setting from query to query, hid the query translation and showed the retrieved set as ranked list primary. Despite the fact that this new design was considered to be more effective, a comparison between the first layout based on the relevant literature and the new one based on the user study was considered an important research question. In particular, the choice of hiding the query translation was considered an important design decision, against the common agreement to allow and support the user in controlling the system actions. Thus the participation of Sheffield in iCLEF was organized around the idea of checking if the user should validate the query translation before the search is run or instead if the system should perform the translation and search in a single step without any user’s supervision

Research on boron filaments and boron reinforced composites

Boron filaments for use as reinforcing phase in composite materials for aerospace structure