Formation and morphology of anomalous solar circular polarization

The morphology of spectral line polarization is the most valuable observable to investigate the magnetic and dynamic solar atmosphere. However, in order to develop solar diagnosis, it is fundamental to understand the different kinds of anomalous solar signals that have been routinely found in linear and circular polarization (LP,CP). The goal of this paper has been to explain and characterize the morphology of solar CP signals by understanding the combined effect of magnetic fields, velocity gradients, and atomic orientation in general NLTE regime. To that aim, an analytical two-layer model of the polarized radiative transfer equation is developed and used to solve the NLTE problem with atomic polarization in a semi-parametric way. The formation of polarization is thus insightfully described with certain precision without resorting in MHD models or sacrifying key physical ingredients. The potential of the model for reproducing solar anomalous CP is shown with detailed calculations. The essential physical behavior of dichroism and atomic orientation is described, introducing the concepts of dichroic inversion, neutral and reinforcing medium, critic intensity spectrum, and critic source function. It is shown that the zero-crossings of the CP spectrum are useful to classify its morphology and understand its formation. This led to identify and explain the morphology of the seven most characteristics CP signals that a single (depth-resolved) scattering layer can produce. Futhermore, it is found that a minimal number of two magnetic layers along the LOS is required to fully explain anomalous solar CP signals, and that the morphology and polarity of Stokes V depends on magnetic, radiative and atomic polarities. Some implications of these results are presented through a preliminar modeling of anomalous CP signals in the Na I D and Fe I 1564.8 nm lines.Comment: 18 pages, 18 figures. Accepted for publication in A&A. Typos and language correcte

Competition, restructuring and firm performance: evidence of an inverted-U relationship from a cross-country survey of firms in transition economies

This paper examines the importance of competition in the growth anddevelopment of firms. We draw on a survey of 3,300 firms in 25transition countries to shed light on the factors that influencerestructuring by firms and their subsequent performance. These datahave three main advantages over those used in previous work. First,they measure directly the degree of competition perceived by each firmin its principal market rather than attempting to infer this from marketdata as measured by statistical agencies. Second, the fact that transitioncountries have market structures inherited from the past avoids some ofthe endogeneity problems associated with measures of competition inmarket economies. Third, the breadth of cross-country variationprovides a method of dealing with the fact that firm-level measures ofthe external environment will not be independent of the firm?s ownperformance. We find evidence of a robust inverted-U effect ofcompetition on performance that is both statistically and economicallysignificant. This paper examines the importance of competition in the growth anddevelopment of firms. We draw on a survey of 3,300 firms in 25transition countries to shed light on the factors that influencerestructuring by firms and their subsequent performance. These datahave three main advantages over those used in previous work. First,they measure directly the degree of competition perceived by each firmin its principal market rather than attempting to infer this from marketdata as measured by statistical agencies. Second, the fact that transitioncountries have market structures inherited from the past avoids some ofthe endogeneity problems associated with measures of competition inmarket economies. Third, the breadth of cross-country variationprovides a method of dealing with the fact that firm-level measures ofthe external environment will not be independent of the firm?s ownperformance. We find evidence of a robust inverted-U effect ofcompetition on performance that is both statistically and economicallysignificant

In the balance: report of a research study exploring information for weight management

This paper uses findings from a research study called Net.Weight to examine the concepts of interaction, information quality and Internet-based information from the perspective of people engaged in managing their weight. The Net.Weight study was a two-year project funded by the British government 19s Department of Health and located in the city of Brighton and Hove. It examined the potential for increased, innovative and effective uses of information and communication technologies (ICTs) to support the self management of weight. The study had several inter-related research strands and the findings discussed in the paper emerged primarily from participatory learning workshops and evaluative interviews. The paper demonstrates that the interaction between people is an important aspect of the information process, which is often neglected in the literature. It suggests that exploring the user-user dimension might add to the understanding of information effectiveness. It also suggests that an approach to information and health literacy which includes a social as well as an individual perspective is necessary. On quality assessment, it supports findings from other studies that organisational authority is a key measure of reliability for lay users and that quality assessment tools have a limited role in the assessment process. The Net.Weight participants embraced the Internet as a medium for weight management information only when it added value to their existing information and weight management practices and when it could be integrated into their everyday lives

Quantum discord in spin-cluster materials

The total quantum correlation (discord) in Heisenberg dimers is expressed via the spin-spin correlation function, internal energy, specific heat or magnetic susceptibility. This allows one to indirectly measure the discord through neutron scattering, as well as calorimetric or magnetometric experiments. Using the available experimental data, we found the discord for a number of binuclear Heisenberg substances with both antiferro- and ferromagnetic interactions. For the dimerized antiferromagnet copper nitrate Cu(NO_3)_2*2.5H_2O, the three independent experimental methods named above lead to a discord of approximately 0.2-0.3 bit/dimer at a temperature of 4 K. We also determined the temperature behavior of discord for hydrated and anhydrous copper acetates, as well as for the ferromagnetic binuclear copper acetate complex [Cu_2L(OAc)]*6H_2O, where L is a ligand.Comment: 7 pages, 6 figure

Information to fight the flab: findings from the Net.Weight study

The purpose of the paper is to examine information use and information literacy in the context of weight management. It reports on a two-year study funded by the Department of Health known informally as the Net.Weight Study. Net.Weight examined the potential for increased, innovative and effective uses of information and communication technologies (ICTs) to support the self management of weight. The research was conducted in the city of Brighton & Hove by an inter-disciplinary team from the University of Brighton. The paper gives a brief overview of the various methods used in the study as a whole but discusses one strand, the user survey, in more detail. The survey gathered data on people’s information and ICT use around weight management. The design of the survey questionnaire required the adaptation of existing literacy assessment instruments and this process is described in this paper. The findings show that people use a wide range of information sources for information and support around weight management. The most useful sources are slimming groups, food packaging, friends and family, magazines, TV and health books, thus representing a variety of media, formal and informal, and including human sources. The internet was reported to be a useful source for around half the survey respondents and is most often used for information about diet and exercise. A majority of respondents described themselves as active information seekers and confident about their information skills. They are less confident about internet information than information generally and even less confident about using the internet to support weight management activities. The concept of literacies, particularly around information and health, provide a framework for examining the Net.Weight findings. The findings are discussed in terms of their implications for health information policy and for those interested in applying information literacy theory to health. The role of healthcare practitioners in weight management information is addressed, as is the need for targeted rather than generic health information. It is suggested that the work done in the education sector to increase awareness of information literacy and improve skills could provide a useful model of good practice in a health context. However, the evidence provided by the Net.Weight study suggests that for such an approach to be relevant it needs to reflect the complexity of health information processes in everyday lives