Radio Frequency Superconducting Quantum Interference Device Meta-atoms and Metamaterials: Experiment, Theory, and Analysis

Metamamterials are 1D, 2D or 3D arrays of articial atoms. The articial atoms, called "meta-atoms", can be any component with tailorable electromagnetic properties, such as resonators, LC circuits, nano particles, and so on. By designing the properties of individual meta-atoms and the interaction created by putting them in a lattice, one can create a metamaterial with intriguing properties not found in nature. My Ph. D. work examines the meta-atoms based on radio frequency superconducting quantum interference devices (rf-SQUIDs); their tunability with dc magnetic field, rf magnetic field, and temperature are studied. The rf-SQUIDs are superconducting split ring resonators in which the usual capacitance is supplemented with a Josephson junction, which introduces strong nonlinearity in the rf properties. At relatively low rf magnetic field, a magnetic field tunability of the resonant frequency of up to 80 THz/Gauss by dc magnetic field is observed, and a total frequency tunability of 100% is achieved. The macroscopic quantum superconducting metamaterial also shows manipulative self-induced broadband transparency due to a qualitatively novel nonlinear mechanism that is different from conventional electromagnetically induced transparency (EIT) or its classical analogs. A near complete disappearance of resonant absorption under a range of applied rf flux is observed experimentally and explained theoretically. The transparency comes from the intrinsic bi-stability and can be tuned on/ off easily by altering rf and dc magnetic fields, temperature and history. Hysteretic in situ 100% tunability of transparency paves the way for auto-cloaking metamaterials, intensity dependent filters, and fast-tunable power limiters. An rf-SQUID metamaterial is shown to have qualitatively the same behavior as a single rf-SQUID with regards to dc flux, rf flux and temperature tuning. The two-tone response of self-resonant rf-SQUID meta-atoms and metamaterials is then studied here via intermodulation (IM) measurement over a broad range of tone frequencies and tone powers. A sharp onset followed by a surprising strongly suppressed IM region near the resonance is observed. This behavior can be understood employing methods in nonlinear dynamics; the sharp onset, and the gap of IM, are due to sudden state jumps during a beat of the two-tone sum input signal. The theory predicts that the IM can be manipulated with tone power, center frequency, frequency difference between the two tones, and temperature. This quantitative understanding potentially allows for the design of rf-SQUID metamaterials with either very low or very high IM response.

Capital structure, risk and asymmetric information : theory and evidence

This paper proposes a principal-agent model between banks and firms with risk and asymmetric information. A mixed form of finance to firms is assumed. The capital structure of firms is a relevant cause for the final aggregate level of investment in the economy. In the model analyzed, there may be a separating equilibrium, which is not economically efficient, because aggregate investments fall short of the first-best level. Based on European firm-level data, an empirical model is presented which validates the result of the relevance of the capital structure of firms. The relative magnitude of equity in the capital structure makes a real difference to the profits obtained by firms in the economy.

The economics of credit markets: theory and evidence.

Doutoramento em Economia.

Optimization of Energy Distribution in Solar Panel Array Configurations by Graph Theory and Minkowski’s Paths

Nowadays, the development of the photovoltaic (PV) technology is consolidated as a source of renewable energy. The research in the topic of maximum improvement on the energy efficiency of the PV plants is today a major challenge. The main requirement for this purpose is to know the performance of each of the PV modules that integrate the PV field in real time. In this respect, a PLC communications based Smart Monitoring and Communications Module, which is able to monitor at PV level their operating parameters, has been developed at the University of Malaga. With this device you can check if any of the panels is suffering any type of overriding performance, due to a malfunction or partial shadowing of its surface. Since these fluctuations in electricity production from a single panel affect the overall sum of all panels that conform a string, it is necessary to isolate the problem and modify the routes of energy through alternative paths in case of PV panels array configuration.

The Anuvrat Movement: Theory and Practice

The slogan: “Self-restraint is life,” forms the philosophical ideal behind the Anuvrat Movement. The purpose of my thesis is to evaluate the Anuvrat Movement introduced by Acharya Tulsi as a non-sectarian, ethical-spiritual movement. The study considered in some detail the historical context within which the movement emerged. The thesis provides a much-needed analysis of the 11 vows formulated by Tulsi in the model of the traditional vows in Jainism. It explored the question whether these vows are relevant and effective in the contemporary Indian society, and whether Tulsi’s movement can cross the geographical boundaries of the Indian sub-continent to be a part of larger global initiatives. The study explored the social significance of the concepts of nonviolence, social justice and sustainability in the wider global community. The study suggests a positive association between the exemplary charismatic role of a leader and the popularity and longevity of social movements in India.

The Relationship between Faculty Perceptions and Implementation of Elements of Transactional Distance Theory and Online Web-Based Course Completion Rates

The purpose of this study was to explore the relationship between faculty perceptions, selected demographics, implementation of elements of transactional distance theory and online web-based course completion rates. This theory posits that the high transactional distance of online courses makes it difficult for students to complete these courses successfully; too often this is associated with low completion rates. Faculty members play an indispensable role in course design, whether online or face-to-face. They also influence course delivery format from design through implementation and ultimately to how students will experience the course. This study used transactional distance theory as the conceptual framework to examine the relationship between teaching and learning strategies used by faculty members to help students complete online courses. Faculty members’ sex, number of years teaching online at the college, and their online course completion rates were considered. A researcher-developed survey was used to collect data from 348 faculty members who teach online at two prominent colleges in the southeastern part of United States. An exploratory factor analysis resulted in six factors related to transactional distance theory. The factors accounted for slightly over 65% of the variance of transactional distance scores as measured by the survey instrument. Results provided support for Moore’s (1993) theory of transactional distance. Female faculty members scored higher in all the factors of transactional distance theory when compared to men. Faculty number of years teaching online at the college level correlated significantly with all the elements of transactional distance theory. Regression analysis was used to determine that two of the factors, instructor interface and instructor-learner interaction, accounted for 12% of the variance in student online course completion rates. In conclusion, of the six factors found, the two with the highest percentage scores were instructor interface and instructor-learner interaction. This finding, while in alignment with the literature concerning the dialogue element of transactional distance theory, brings a special interest to the importance of instructor interface as a factor. Surprisingly, based on the reviewed literature on transactional distance theory, faculty perceptions concerning learner-learner interaction was not an important factor and there was no learner-content interaction factor.

Rethinking management theory and practice for the Indian context:an international management perspective

The Indian economy characterized variously as a slumbering giant, powerful tiger, and the most promising market has witnessed a slowdown, occasional disturbances in the industrial relations space, and attention of the world in the last five years. In this special issue, we raise pertinent questions and present research on multiple dimensions of the dynamic and rapidly changing business environment of India. The suitability of management models and frameworks developed in the North American contexts in emerging markets like India and China is questioned. One example of how the well-established models in the literature on success of international joint ventures were insufficient to explain the success of three international joint ventures in the insurance space in India is presented as case in point. Finally, the nine papers that materially contribute to the theme of this special issue are introduced. © 2016 Wiley Periodicals, Inc.

Prospect theory and the effects of bankruptcy laws on entrepreneurial aspirations

We apply prospect theory to explain how personal and corporate bankruptcy laws affect risk perceptions of entrepreneurs at time of entry and therefore their growth ambitions. Previous theories have reached ambiguous conclusions as to whether countries with more debtor-friendly bankruptcy laws (i.e. laws that are more forgiving towards debtors in bankruptcy proceedings) are likely to have more entrepreneurs, or whether, creditorfriendly regimes have positive effects on new ventures via enhanced incentives for the supply of credit to entrepreneurs. Responding to this ambiguity, we apply prospect theory to propose that entrepreneurs do not attach the same significance to different elements of bankruptcy codes—and to explain which aspects of debtor-friendly bankruptcy laws matter more to entrepreneurs. Based on this, we derive and confirm hypotheses about the impact of aspects of bankruptcy codes on entrepreneurial activity using the Global Entrepreneurship Monitor combined with data on both personal and corporate bankruptcyregulations for 15 developed OECD countries. We use multilevel random coefficient logistic regressions to take account of the hierarchical nature of the data (country and individual levels). Because entrepreneurs and creditors are sensitive to different elements of the codes, there is scope for optimisation of the legal design of bankruptcy law to achieve both an adequate supply of credit and to encourage high-ambition entrepreneurship.

Theory and optimisation of 1.3 and 1.55 μm (Al)InGaAs metamorphic quantum well lasers

The use of InGaAs metamorphic buffer layers (MBLs) to facilitate the growth of lattice-mismatched heterostructures constitutes an attractive approach to developing long-wavelength semiconductor lasers on GaAs substrates, since they offer the improved carrier and optical confinement associated with GaAs-based materials. We present a theoretical study of GaAs-based 1.3 and 1.55 μm (Al)InGaAs quantum well (QW) lasers grown on InGaAs MBLs. We demonstrate that optimised 1.3 μm metamorphic devices offer low threshold current densities and high differential gain, which compare favourably with InP-based devices. Overall, our analysis highlights and quantifies the potential of metamorphic QWs for the development of GaAs-based long-wavelength semiconductor lasers, and also provides guidelines for the design of optimised devices.

Agency theory and the family business

The conceptual domain of agency theory is one of the dominant organisational theory perspectives applied in current family business research (Chrisman et al., 2010). According to agency theory (Jensen and Meckling, 1976), agency costs generally arise due to individuals’ selfinterest and decision making based on rational thinking and oriented toward own preferences. With more people involved in decision making, such as through the separation of ownership and management, agency costs occur due to different preferences and information asymmetries between the owner (principal) and the employed management (agent) (Jensen and Meckling, 1976). In other words, agents take decisions based on their individual preferences (for example, short term, financial gains) instead of the owners’ preferences (for example, long term, sustainable development).

Behavioural agency theory and the family business

The behavioural agency theory was developed to provide a more comprehensive explanation and prediction of managerial risk taking, in response to some shortcomings of agency theory. In general, the theory offers explanations of why decision makers prefer some strategic choices to others. The use of behavioural agency theory in family business research has, however, been very limited. Family business scholars recently adapted this theory to construct the family business variant, the ‘socioemotional wealth’ construct, which offers better explanations for the risk taking and decision making behaviours of family firms. This chapter provides an overview of behavioural agency theory and the socioemotional wealth construct, explores how they have been used in family business research, and offers suggestions for how this theory can be used in further research to contribute to both the family business and the general management literature. Keywords: family business, behavioural agency theory, socioemotional wealth, family firm heterogeneity.

Behavioural theory and the family business

Fifty years have passed since Cyert and March’s 1963 A Behavioral Theory of the Firm. During this time, BTOF has been adopted across different research domains to investigate how organizations set goals, how they determine aspirations and how they finally react to performance aspiration discrepancies. Cyert and March’s framework has also recently emerged as one of the dominant paradigms to understand the ways in which family business organizations make decisions. In this chapter, I review the theoretical development and empirical results of BTOF and its application in the family business field of study in order to identify theoretical and empirical gaps and propose suggestions for future research. The conclusions suggest that BTOF is both a theoretically and empirically valid perspective in family business research, particularly when combined with other theoretical frameworks. The principal recommendation is to apply behavioral theory to enhance scholarly understanding of  how family organisations define their aspiration levels and respond to organizational problems. 

Critical pedagogy theory and the family business

In contemporary times family business research has been dominated by three theoretical perspectives; principal-agent theory, stewardship theory, and resource-based view theory (Siebels 2012) but at the same time scholars argue that what still needs further attention is how underlying processes and phenomena can be explained (Melin, Nordqvist & Sharma  2014). In order to understand themes such as repression or relations of asymmetry the suggestion in this chapter is to move towards a critical stance of thinking which involves problematizing the obvious issues in family firms (Alvesson & Deetz 2000) and moreover allowing the critical perspective to destabilize assumptions made within earlier research (Freire, 1974). By discussing critical theory in general but foremost the Freirean  (1970, 1974) critical pedagogy specifically, the arguments in the chapter revolves around how critical pedagogy can open up for a more novel view on family business. The purpose is via critical pedagogy discuss family business from a limited situation perspective, and to argue for a Freirean (1970) dialogue as means of developing a critical consciousness for family members in the family business context. The chapter concludes with some recommendations on platforms or common grounds in which dialogue and raising of consciousness can occur in which the concept can open up possibilities for interesting learning transfer and bring multidimensional knowledge into the family firm.

Gender theory and the family business

Gender Theory started in understanding and explain women's role in society and are also now including men and masculinities, Gender Theory has recently been adapted to family business research. This chapter will briefly introduce Gender Theory and its development, before reviewing how it has been used in family business research. Arguing that the family business context is suitable in studying gender phenomena, the chapter outlines several ways through which Gender Theory could yield new insights into issues, of how family business structures, settings and practices produce relations of power or asymmetry. A common approach so far to the study of gender in family business situations is to consider ‘gender as a variable’, which maintains the categorisation of women and men as a relevant and unproblematic variable. Many analyses of family businesses that also address gender focus on feminist ‘standpoint positions’, giving voice to women´s unique experiences. Often in family business research, the dominant approach is to conceive gender in terms of limited male/female distinctions rather than by reframing family business through critical positions, with the aim of reflection and sensitivity towards gender issues in terms of the socially constituted patterns that are produced through male/female, masculine/feminine distinctions. Concluding, the chapter suggests a possible methodology for capturing gendered processes and proposes how family business research could offer new insights into Gender theory.

Ranganathan’s Layers of Classification Theory and the FASDA Model of Classification

Describes four waves of Ranganathan’s dynamic theory of classification. Outlines components that distinguish each wave, and porposes ways in which this understanding can inform systems design in the contemporary environment, particularly with regard to interoperability and scheme versioning. Ends with an appeal to better understanding the relationship between structure and semantics in faceted classification schemes and similar indexing languages.