Maximum-entropy theory of steady-state quantum transport

We develop a theoretical framework for describing steady-state quantum transport phenomena, based on the general maximum-entropy principle of nonequilibrium statistical mechanics. The general form of the many-body density matrix is derived, which contains the invariant part of the current operator that guarantees the nonequilibrium and steady-state character of the ensemble. Several examples of the theory are given, demonstrating the relationship of the present treatment to the widely used scattering-state occupation schemes at the level of the self-consistent single-particle approximation. The latter schemes are shown not to maximize the entropy, except in certain limits

Unequal access to testing and vaccination services for the homeless and undocumented population during the COVID-19 pandemic

Objectives: To furnish a model to ensure access and use of healthcare services to the undocumented and homeless population. Methods: Between March 2020 and October 2021, public and third sector actors in Rome implemented an accessible COVID-19 screening service and vaccination program targeting the homeless and undocumented population. Results: 95.6% of the patients tested negative to both rapid and molecular tests. 0.9% tested positive to both. 0.7% were false negatives, while 2.8% were false positives. None of the participants refused the diagnostic treatment. From July to October 2021, 1384 people received a complete cycle of the COVID-19 vaccine through the program. 632 (45.6%) also agreed to perform the antibodies testing before inoculation. 318 (50.31%) of these were positive at the time of vaccination. Conclusion: We present a cost-effective model for reducing structural barriers to access diagnostic and preventive services for the homeless and undocumented population that can be applied to different public health settings

The Information Content of Earnings Announcements in Regulated and Deregulated Markets: The Case of the Airline Industry

Most of the accounting research examining the information content of earnings assumes a competitive market framework. Little research has been devoted to the value relevance of earnings announcements in regulated markets. This paper examines the information content of earnings releases under two economic conditions facing the airline industry: regulation and deregulation (i.e., competition). We hypothesize that in a deregulated (competitive) environment, there is greater competition, causing more risk and uncertainty for the investor in setting security prices. Therefore, earnings\u27 releases provide more useful information in resolving uncertainties and in formulating and revising the investor\u27s beliefs regarding future earnings and prices in deregulated than for regulated markets. Three critical event periods are examined: the regulation period (1973 - 1975), the transition period (1976 - 1978), and the deregulation period (1979 - 1981). A revaluation index (RI) and a standardized revaluation index (SRI) are used to examine the extent of airline stock price revaluation in response to quarterly accounting earnings releases during the three critical event periods. The results indicate that earnings announcements have value relevance in setting security prices in both regulated and deregulated market conditions. However, the level of the market revaluation to earnings releases is dependent on market structure. The market revaluation to earnings releases is greater in a deregulated (competitive) period than in a regulated one. This result confirms the hypothesis that earnings have more value relevance in competitive markets than in regulated ones. The findings of this research have direct implications for the level of accounting disclosure and the extent of financial reporting in a given market structure. Since financial reporting is a costly process, it becomes important to identify the circumstances under which the level of financial disclosure should be expanded or reduce

An Institutional Framework for Heterogeneous Formal Development in UML

We present a framework for formal software development with UML. In contrast to previous approaches that equip UML with a formal semantics, we follow an institution based heterogeneous approach. This can express suitable formal semantics of the different UML diagram types directly, without the need to map everything to one specific formalism (let it be first-order logic or graph grammars). We show how different aspects of the formal development process can be coherently formalised, ranging from requirements over design and Hoare-style conditions on code to the implementation itself. The framework can be used to verify consistency of different UML diagrams both horizontally (e.g., consistency among various requirements) as well as vertically (e.g., correctness of design or implementation w.r.t. the requirements)

Social dimension of risk behaviours among adolescent prostitutes: Insight from South-Western Nigeria

This study examined the social dimension of risk behaviours among adolescent prostitutes in Lagos metropolis, Nigeria. More specifically, it examined the relationship between educational attainment and use of drug among female adolescent sex workers, investigated the relationship between use of drug and tendency for criminal behaviour among female adolescent sex workers, examined the impact of drug use on the nature of sex of female adolescent sex workers, established the relationship between educational attainment and consistent use of male condom by female adolescent sex workers. Cross-sectional survey and in-depth interview research methods were adopted to generate both quantitative and qualitative data from the respondents. Findings of the study showed that 90.7% of the respondents joined the sex industry because of poverty and lack of other means of getting daily food. 98.6% of the respondents that participated in the research inquiry had knowledge about diseases that can be transmitted through sexual intercourse; while all the respondents had knowledge about the existence of HIV/AIDS, 91.7% of them identified sexual intercourse as a major route of HIV transmission. There was a significant relationship between the use of drug and nature of sex of female sex workers at P < 0.05. Specifically, 99.7% of the respondents used male condoms regularly in every sexual act, 5.5% of the respondents used female condoms at irregular intervals in every sexual act, while 84.8% compromised the use of condoms with financial rewards. Consequently, a high percentage of the population was assumed to be at risk of HIV/AIDS, while 7.2% of the sample had become pregnant while on the job and 3.1% of these pregnancies were terminated through induced abortion. Furthermore, 44.1% of the drug-addicted and low-income sex workers were found to be mostly involved in criminal activities while 60.3% of the sampled populations were victims of different types of violent sexual experience. In conclusion, socio-economic constraints are the primary factors that push adolescent girls into prostitution in Nigeria and these same factors hinder them from practicing safe sex within the sex industry. Thus, it is recommended that the Nigerian government should develop programmes that will reduce poverty level and unemployment trend, in order to reduce adolescent/adult prostitution with its attendant problems of HIV transmission and criminal activities in the country

A coalgebraic perspective on logical interpretations

In Computer Science stepwise refinement of algebraic specifications is a well-known formal methodology for rigorous program development. This paper illustrates how techniques from Algebraic Logic, in particular that of interpretation, understood as a multifunction that preserves and reflects logical consequence, capture a number of relevant transformations in the context of software design, reuse, and adaptation, difficult to deal with in classical approaches. Examples include data encapsulation and the decomposition of operations into atomic transactions. But if interpretations open such a new research avenue in program refinement, (conceptual) tools are needed to reason about them. In this line, the paper’s main contribution is a study of the correspondence between logical interpretations and morphisms of a particular kind of coalgebras. This opens way to the use of coalgebraic constructions, such as simulation and bisimulation, in the study of interpretations between (abstract) logics.Fundação para a Ciência e a Tecnologia (FCT