Determining the specification of a control system from that of its environment

Well understood methods exist for developing programs from given specifications. A formal method identifies proof obligations at each development step: if all such proof obligations are discharged, a precisely defined class of errors can be excluded from the final program. For a class of closed systems such methods offer a gold standard against which less formal approaches can be measured. For open systems -those which interact with the physical world- the task of obtaining the program specification can be as challenging as the task of deriving the program. And, when a system of this class must tolerate certain kinds of unreliability in the physical world, it is still more challenging to reach confidence that the specification obtained is adequate. We argue that widening the notion of software development to include specifying the behaviour of the relevant parts of the physical world gives a way to derive the specification of a control system and also to record precisely the assumptions being made about the world outside the computer.

Towards a Modeling Environment for Earth Systems Simulations

The developments of models in Earth Sciences, e.g. for earthquake prediction and for the simulation of mantel convection, are fare from being finalized. Therefore there is a need for a modelling environment that allows scientist to implement and test new models in an easy but flexible way. After been verified, the models should be easy to apply within its scope, typically by setting input parameters through a GUI or web services. It should be possible to link certain parameters to external data sources, such as databases and other simulation codes. Moreover, as typically large-scale meshes have to be used to achieve appropriate resolutions, the computational efficiency of the underlying numerical methods is important. Conceptional this leads to a software system with three major layers: the application layer, the mathematical layer, and the numerical algorithm layer. The latter is implemented as a C/C++ library to solve a basic, computational intensive linear problem, such as a linear partial differential equation. The mathematical layer allows the model developer to define his model and to implement high level solution algorithms (e.g. Newton-Raphson scheme, Crank-Nicholson scheme) or choose these algorithms form an algorithm library. The kernels of the model are generic, typically linear, solvers provided through the numerical algorithm layer. Finally, to provide an easy-to-use application environment, a web interface is (semi-automatically) built to edit the XML input file for the modelling code. In the talk, we will discuss the advantages and disadvantages of this concept in more details. We will also present the modelling environment escript which is a prototype implementation toward such a software system in Python (see www.python.org). Key components of escript are the Data class and the PDE class. Objects of the Data class allow generating, holding, accessing, and manipulating data, in such a way that the actual, in the particular context best, representation is transparent to the user. They are also the key to establish connections with external data sources. PDE class objects are describing (linear) partial differential equation objects to be solved by a numerical library. The current implementation of escript has been linked to the finite element code Finley to solve general linear partial differential equations. We will give a few simple examples which will illustrate the usage escript. Moreover, we show the usage of escript together with Finley for the modelling of interacting fault systems and for the simulation of mantel convection.

Universal duality in a Luttinger liquid coupled to a generic environment

We study a Luttinger liquid (LL) coupled to a generic environment consisting of bosonic modes with arbitrary density-density and current-current interactions. The LL can be either in the conducting phase and perturbed by a weak scatterer or in the insulating phase and perturbed by a weak link. The environment modes can also be scattered by the imperfection in the system with arbitrary transmission and reflection amplitudes. We present a general method of calculating correlation functions under the presence of the environment and prove the duality of exponents describing the scaling of the weak scatterer and of the weak link. This duality holds true for a broad class of models and is sensitive to neither interaction nor environmental modes details, thus it shows up as the universal property. It ensures that the environment cannot generate new stable fixed points of the renormalization group flow. Thus, the LL always flows toward either conducting or insulating phase. Phases are separated by a sharp boundary which is shifted by the influence of the environment. Our results are relevant, for example, for low-energy transport in (i) an interacting quantum wire or a carbon nanotube where the electrons are coupled to the acoustic phonons scattered by the lattice defect; (ii) a mixture of interacting fermionic and bosonic cold atoms where the bosonic modes are scattered due to an abrupt local change of the interaction; (iii) mesoscopic electric circuits.

Explaining the effects of class size on faculty and students

This study explored the effects of class size on faculty and students. Specifically, it examined the relationship of class size and students' participation in class, faculty interactive styles, and academic environment and how these behaviors affected student achievement (percentage of students passing). The sample was composed of 629 students in 30 sections of Algebra I at a large, urban community college. A survey was administered to the students to solicit their perceptions on their participation in class, their faculty interaction style, and the academic environment in their classes. Selected classes were observed to triangulate the findings. The relationship of class size to student participation, faculty interactive styles, and academic environment was determined by using hierarchical linear modeling (HLM). A significant difference was found on the participation of students related to class size. Students in smaller classes participated more and were more engaged than students in larger classes. Regression analysis using the same variables in small and large classes showed that faculty interactive styles significantly predicted student achievement. Stepwise regression analyses of student and faculty background variables showed that (a) students' estimate of GPA was significantly related to their achievement (r = .63); (b) older students reported more participation than did younger ones, (c) students in classes taught by female, Hispanic faculty earned higher passing grades, and (d) students' participation was greater with adjunct professors. Class observations corroborated these findings. The analysis and observational data provided sufficient evidence to warrant the conclusion that small classes were not always most effective in promoting achievement. It was found that small classes may be an artifact of ineffectual teaching, actual or by reputation. While students in small classes participate and are more engaged than students in larger classes, the class-size effect is essentially due to what happens in instruction to promote learning. The interaction of the faculty with students significantly predicted students' achievement regardless of class size. Since college students select their own classes, students do not register for classes taught by faculty with poor teaching reputation, thereby leading to small classes. Further studies are suggested to determine reasons why classes differ in size.

Three essays on dual-class stock structure

Dual-class stock structure is characterized by the separation of voting rights and cash flow rights. The departure from a common "one share-one vote" configuration creates ideal conditions for conflicts of interest and agency problems between controlling insiders (the holders of voting rights) and remaining shareholders. The owners of voting rights have the opportunity to extract private benefits and act in their personal interest; as a result, dual-class firms are often perceived to have low transparency and high information asymmetry. This dissertation investigates the quality of information and the information environment of firms with two classes of stock. The first essay examines the quality of information by studying accruals in dual-class firms in comparison to firms with only one class of stock. The results suggest that the quality of accruals is better in dual-class firms than in single-class firms. In addition, the difference in the quality of accruals between firms that abolish their dual-class share structure by unification and singe-class firms disappears in the post-unification period. The second essay investigates the earnings informativeness of dual-class firms by examining the explanatory power of earnings for returns. The results indicate that the earnings informativeness is lower for dual-class firms as compared to single-class firms. Earnings informativeness improves in firms that unify their shares. The third essay compares the level of information asymmetry between dual-class firms and single-class firms. It is documented that the information environment for dual-class firms is worse than for single-class firms. Also, the finding suggests that the difference in information environment between dual-class firms and single-class firms disappears after dual-class stock unification.

Middle -class immigrant identities: Dominican-Americans in South Florida

Identity studies of immigrants are complex because of multiple influences affecting identity reconstruction during immigration and acculturation: nationality, socio-cultural differences, occupations, education, spatial and geographic locations, age, gender, and personal attributes. Most immigrant identity studies deal with lower-income immigrants, who do not have the resources of middle- and upper-middle-class immigrants. South Florida is “home” to many middle-class immigrants, including Dominican-Americans. This dissertation interviewed sixty-six Dominican immigrants in South Florida, in order to determine their reconstructed identities after immigration/resettlement and to discover what influences contributed to these changes in identities. ^ The research design of this dissertation utilized an inductive, qualitative model, with the “grounded theory” method of data collection, categorization, and analysis. Participants were selected by a snowball sampling and interviewed with an informal questionnaire. Results were transcribed, categorized, tabulated, and analyzed for conclusions and theorization on immigrant identity. ^ The dissertation addressed numerous influences relating to identity reconstruction: the differing circumstances of immigration, the unique resources of middle- and higher-class immigrants, the nurturing environment of South Florida for immigrants with education and professional skills, and the boundary protection offered by suburban spaces. The interviewees displayed a wide range of age, length of residence in the United States, reasons for immigration, entry ports, settlement, relocations, occupations, and claimed identities. Identity was cross-tabulated with the various influences, as a means of invalidating certain influences and indicating possible trends. ^ The dissertation concluded that middle-class immigrant identities are diverse and multiple, as are the related influences. None of these immigrants had become totally assimilated, nor have they retained dual, non-overlapping attachments or frames of reference. Instead, many of the immigrants seemed to have developed or negotiated two or more identities, according to need, context, and personal interest. A cosmopolitan community such as South Florida seems to have encouraged such multiplicity of identity. However, rather than forming free-flowing identities, most of these immigrants eventually developed diverse and hybrid identities that have bounded attachments to various networks, groups, and places in South Florida. ^

The 1993 BFA Graduating Class Department of Visual Arts

The Graduate students in the Visual Arts program have selected for inclusion in this cataloguepieces that symbolize the Acomplishments of the years of study and application. The images are the summary of a complex of learning experiences, both theoretical and applied. They reflect the critical processes of the studio, the Library, the environment and the traditional classroom; they are the results of dynamic and rigorous interaction between teachers and colleagues, peers and mentors, throughout this undergraduate experience.

Major Histocompatibility Complex (MHC) Class II sequence polymorphism in long-finned pilot whale (Globicephala melas) from the North Atlantic

Funding Silvia S. Monteiro and Marisa Ferreira were supported by a Ph.D. grant from Fundação para a Ciência e Tecnologia (ref SFRH/BD/38735/2007 and SFRH/BD/30240/2006, respectively). Alfredo López was supported by a postdoctoral grant from Fundação para a Ciência e Tecnologia (ref SFRH/BPD/82407/2011). Catarina Eira is supported by CESAM (UID/AMB/50017), from FCT/MEC through national funds and FEDER (PT2020, Compete 2020). The work related with strandings and tissue collection in Portugal was partially supported by the SafeSea Project EEAGrants PT 0039 (supported by Iceland, Liechtenstein and Norway through the EEA Financial Mechanism), by the Project MarPro–Life09 NAT/PT/000038 (funded by the European Union–Program Life+) and by the project CetSenti FCT RECI/AAG-GLO/0470/2012; FCOMP-01-0124-FEDER-027472 (Funded by the Program COMPETE and Fundação para a Ciência e Tecnologia).

Climbing Up the Leaderboard: An Empirical Study of Applying Gamification Techniques to a Computer Programming Class

Conventional taught learning practices often experience difficulties in keeping students motivated and engaged. Video games, however, are very successful at sustaining high levels of motivation and engagement through a set of tasks for hours without apparent loss of focus. In addition, gamers solve complex problems within a gaming environment without feeling fatigue or frustration, as they would typically do with a comparable learning task. Based on this notion, the academic community is keen on exploring methods that can deliver deep learner engagement and has shown increased interest in adopting gamification – the integration of gaming elements, mechanics, and frameworks into non-game situations and scenarios – as a means to increase student engagement and improve information retention. Its effectiveness when applied to education has been debatable though, as attempts have generally been restricted to one-dimensional approaches such as transposing a trivial reward system onto existing teaching materials and/or assessments. Nevertheless, a gamified, multi-dimensional, problem-based learning approach can yield improved results even when applied to a very complex and traditionally dry task like the teaching of computer programming, as shown in this paper. The presented quasi-experimental study used a combination of instructor feedback, real time sequence of scored quizzes, and live coding to deliver a fully interactive learning experience. More specifically, the “Kahoot!” Classroom Response System (CRS), the classroom version of the TV game show “Who Wants To Be A Millionaire?”, and Codecademy’s interactive platform formed the basis for a learning model which was applied to an entry-level Python programming course. Students were thus allowed to experience multiple interlocking methods similar to those commonly found in a top quality game experience. To assess gamification’s impact on learning, empirical data from the gamified group were compared to those from a control group who was taught through a traditional learning approach, similar to the one which had been used during previous cohorts. Despite this being a relatively small-scale study, the results and findings for a number of key metrics, including attendance, downloading of course material, and final grades, were encouraging and proved that the gamified approach was motivating and enriching for both students and instructors.

Sources of antibiotic resistance in the environment

The discovery of antibiotics was a major breakthrough in medicine. However, short after their introduction in clinical practice resistant bacteria were detected. Nowadays, antibiotic resistance constitutes a serious public health problem. In hospital settings, with high resistance levels, reducing drastically the therapeutic options. Carbapenems are last-resort antibiotics used in Portugal, only in hospitals, to treat serious infections. Bacterial resistance towards this class of antibiotics has increased during last years. In Gram-negative bacteria the production of carbapenemases is a common resistance mechanism. OXA-48 is a carbapenemase of Ambler class D and represents a major concern for human health. It is frequently detected in clinical isolates of Enterobacteriaceae. There are few studies suggesting that genes encoding for OXA-48 variants originated from genes present in the chromosome of members of genus Shewanella, and have disseminated to Enterobacteriaceae members, associated with mobile genetic elements. The aim of this study was to characterize strains from different sources of Shewanella to confirm its role as OXA-48 progenitor. For this, the phylogenetic affiliation of 33 strains of Shewanella was performed by 16SrDNA and gyrB sequencing. The most common species were S. hafniensis and S. xiamenensis, but also S. aestuarii, S. baltica, S. indica, S. haliotis, S. putrefaciens, S. algidipiscicola, S. irciniae, S. algae and S. fodinae were identified. blaOXA-48-like genes were detected in 21 isolates: S. hafniensis (8/8), S. xiamenensis (5/5), S. baltica (4/4), S. algae (1/1), S. fodinae (1/1), S. putrefaciens (1/2) and S. algidipiscicola (1/2). Sequence analysis revealed that genes encoded enzymes identical to OXA-48, OXA-181 and OXA-204 but also new variants differing from OXA-48 from 2 to 81 aminoacids. Genetic context analysis revealed the C15 gene upstream and lysR gene downstream, identical to what has been identified so far flanking blaOXA-48-like genes in Shewanella spp. The assessment of antibiotic susceptibility was performed for all isolates using the disk diffusion method. In general, it was observed a great sensitivity for all antibiotics except to amoxicillin and aztreonam. Multidrug resistance was detected in only 1 isolate. Other resistance genes and the presence of integrons were not identified. Plasmids were detected in 30.3% isolates (10/ 33). These results reinforce the role of Shewanella spp. as origin of blaOXA-48-like genes.

Three Essays on Dual-Class Stock Structure

Dual-class stock structure is characterized by the separation of voting rights and cash flow rights. The departure from a common “one share-one vote” configuration creates ideal conditions for conflicts of interest and agency problems between controlling insiders (the holders of voting rights) and remaining shareholders. The owners of voting rights have the opportunity to extract private benefits and act in their personal interest; as a result, dual-class firms are often perceived to have low transparency and high information asymmetry. This dissertation investigates the quality of information and the information environment of firms with two classes of stock. The first essay examines the quality of information by studying accruals in dual-class firms in comparison to firms with only one class of stock. The results suggest that the quality of accruals is better in dual-class firms than in single-class firms. In addition, the difference in the quality of accruals between firms that abolish their dual-class share structure by unification and singe-class firms disappears in the post-unification period. The second essay investigates the earnings informativeness of dual-class firms by examining the explanatory power of earnings for returns. The results indicate that the earnings informativeness is lower for dual-class firms as compared to single-class firms. Earnings informativeness improves in firms that unify their shares. The third essay compares the level of information asymmetry between dual-class firms and single-class firms. It is documented that the information environment for dual-class firms is worse than for single-class firms. Also, the finding suggests that the difference in information environment between dual-class firms and single-class firms disappears after dual-class stock unification.

Abstraction and use of groundwater for heating buildings in a hard rock environment

In order to turn more efficient the heating of class rooms in the lower floor of the old building of the University of Évora (a XVI century building), five drillings were organised inside the area of the university (Figure 1). The purpose was to use the temperature differential of groundwater in relation to air, by means of a heat exchanger, and use this process to heat the rooms using less energy, turning the heating process less expensive. The wells were drilled in fractured rocks (gneisses), and the purpose was to locate them at least around 100 m one from each other, whilst trying to have a hydraulic connection in-between. From the five initial wells, four were successful in terms of productivity, but just two of them (RA1 and RA2) proved to be hydraulically connected. The wells were equipped with screens for all their drilled depth (100 m), except for the first six meters and some two or three pipes of six meters each, to allow space for the installation for submersible pumps. The length of the installed screens guarantees a good efficiency of the system. In the wells with no connection, the heating system can work using each single well for abstraction and injection, but the process is much less efficient than in the cases where interaction between wells is possible through the rock’s fracture network.

The extracurriculum in an input-poor environment

This paper reports on the experiences of an extracurricular program in English language learning (ELL) that was implemented in an institute of technology in the hinterland of the People's Republic of China (PRC). Following the guidelines set out in an impact study of the reform of curriculum change in Hong Kong (Adamson & Morris, 2000), this study takes account of the context of the particular socio-cultural and political environment in which the research program takes place. Three distinct phases emerged in the career of the extracurricular program - the establishment of the program; successful implementation; and the decline. The study identifies three key factors that shaped these phases: teacher motivation; student motivation and its various influences; and available resources (including collegial and administrative support). The findings suggest that of the key factors impacting on the ELL extracurriculum, student motivation was the most influential.