Flexible multivariate GARCH modeling with an application to international stock markets

This paper offers a new approach to estimating time-varying covariance matrices in the framework of the diagonal-vech version of the multivariate GARCH(1,1) model. Our method is numerically feasible for large-scale problems, produces positive semidefinite conditional covariance matrices, and does not impose unrealistic a priori restrictions. We provide an empirical application in the context of international stock markets, comparing the nev^ estimator with a number of existing ones.

On an organizational level: How can the emergency department at Rouge Valley Centenary hospital improve their wait times?

The prolonged wait times may arguably put into question the Canadian Health Act of 1984. Statistics show throughput wait times are 5.5 hours and output wait times for admitted patients are 32.4 hours. After probing and analyzing best practices through a qualitative/quantitative Value Stream Mapping and a qualitative SWOT Analysis; Team Triage and an Overcapacity Protocol is suggested to improve non-admitted patients wait times by 1.89 hours and admitted patients wait times by 16 hours by eliminating wasteful steps in the patient process and upon overcapacity, effectively sharing already stabilized and admitted patients with all wards in the hospital.

Experimental and modeling studies on reverse electrodialysis for sustainable power generation

A potentially renewable and sustainable source of energy is the chemical energy associated with solvation of salts. Mixing of two aqueous streams with different saline concentrations is spontaneous and releases energy. The global theoretically obtainable power from salinity gradient energy due to World’s rivers discharge into the oceans has been estimated to be within the range of 1.4-2.6 TW. Reverse electrodialysis (RED) is one of the emerging, membrane-based, technologies for harvesting the salinity gradient energy. A common RED stack is composed by alternately-arranged cation- and anion-exchange membranes, stacked between two electrodes. The compartments between the membranes are alternately fed with concentrated (e.g., sea water) and dilute (e.g., river water) saline solutions. Migration of the respective counter-ions through the membranes leads to ionic current between the electrodes, where an appropriate redox pair converts the chemical salinity gradient energy into electrical energy. Given the importance of the need for new sources of energy for power generation, the present study aims at better understanding and solving current challenges, associated with the RED stack design, fluid dynamics, ionic mass transfer and long-term RED stack performance with natural saline solutions as feedwaters. Chronopotentiometry was used to determinate diffusion boundary layer (DBL) thickness from diffusion relaxation data and the flow entrance effects on mass transfer were found to avail a power generation increase in RED stacks. Increasing the linear flow velocity also leads to a decrease of DBL thickness but on the cost of a higher pressure drop. Pressure drop inside RED stacks was successfully simulated by the developed mathematical model, in which contribution of several pressure drops, that until now have not been considered, was included. The effect of each pressure drop on the RED stack performance was identified and rationalized and guidelines for planning and/or optimization of RED stacks were derived. The design of new profiled membranes, with a chevron corrugation structure, was proposed using computational fluid dynamics (CFD) modeling. The performance of the suggested corrugation geometry was compared with the already existing ones, as well as with the use of conductive and non-conductive spacers. According to the estimations, use of chevron structures grants the highest net power density values, at the best compromise between the mass transfer coefficient and the pressure drop values. Finally, long-term experiments with natural waters were performed, during which fouling was experienced. For the first time, 2D fluorescence spectroscopy was used to monitor RED stack performance, with a dedicated focus on following fouling on ion-exchange membrane surfaces. To extract relevant information from fluorescence spectra, parallel factor analysis (PARAFAC) was performed. Moreover, the information obtained was then used to predict net power density, stack electric resistance and pressure drop by multivariate statistical models based on projection to latent structures (PLS) modeling. The use in such models of 2D fluorescence data, containing hidden, but extractable by PARAFAC, information about fouling on membrane surfaces, considerably improved the models fitting to the experimental data.

Modeling and forecasting value-at-risk for the Portuguese stock market

The aim of this work project is to find a model that is able to accurately forecast the daily Value-at-Risk for PSI-20 Index, independently of the market conditions, in order to expand empirical literature for the Portuguese stock market. Hence, two subsamples, representing more and less volatile periods, were modeled through unconditional and conditional volatility models (because it is what drives returns). All models were evaluated through Kupiec’s and Christoffersen’s tests, by comparing forecasts with actual results. Using an out-of-sample of 204 observations, it was found that a GARCH(1,1) is an accurate model for our purposes.

(Un)ethical leadership, organizational identification and sensemaking: the BES case and its impact on employees

This paper provides an ongoing analysis to one of the biggest ethical and financial scandals in Portugal – Banco Espírito Santo (BES). BES was considered one of the three best banks but it went bankrupted and its employees were transferred to a new entity – Novo Banco. This study was conducted in order to provide an understanding of the employees’ side, which has been forgotten so far. An ethical scandal (sensebreaking) creates ambiguity and uncertainty which triggers new sensemaking processes in order to understand and derive meaning from the new reality. The methodology followed was semi-structured interviews to employees both from the branches and the central services. We found evidence that in organizations with strong identification, unethical behavior has a significant impact on followers’ – the new process of sensemaking is particularly important in this situation because employees suffer more from the disruption of their reality.

The impact of talent management practices on employee retention: The moderator effect of leader-member exchange and role modeling

Organizations are undergoing serious difficulties to retain talent. Authors argue that Talent Management (TM) practices create beneficial outcomes for individuals and organizations. However, there is no research on the leaders’ role in the functioning of these practices. This study examines how LMX and role modeling influence the impact that TM practices have on employees’ trust in their organizations and retention. The analysis of two questionnaires (Nt1=175; Nt2=107) indicated that TM only reduced turnover intentions, via an increase in trust in the organization, when role modeling was high and not when it was low. Therefore, we can say that leaders are crucial in the TM context, and in sustaining a competitive advantage for organizations.

Ethical leadership and unethical pro-organizational behavior: A moderated mediation model of affective commitment and authenticity at work

Recently, unethical conduct in the workplace has been a focus of literature and media. Unethical pro-organizational behavior (UPB) refers to unethical conduct that employees engage in to benefit the organization. Given the complexity of UPB, there is an increasing need to understand how and under what conditions this attitude originates within organizations. Based on a sample of 167 employees and seven organizations, results support the moderated mediation model. An ethical leader increases employees’ organizational affective commitment which increases the likelihood to engage in UPB. However, the indirect relationship diminishes when employees feel authentic at work.

Leadership in Angola and Mozambique: How Portuguese leaders overcome the human resources challenge and contribute to organizational success

This Work Project presents human resources as one of the major challenges that Portuguese leaders meet in Angola and Mozambique. The main goal is to understand the role of leaders in translating this challenge into benefits for their own business and the African society. To conduct this study 13 leaders who work in Portugal and Africa were interviewed. Then, a framework was constructed based on the two ways these leaders recognize the importance of their employees for sustainable growth – financial incentives or/and personal development. The main conclusion here is that individually, incentives and personal development are not effective methods. Because of this, an employee empowerment process is proposed that encloses both, along with the leaders’ personal qualities needed to implement that “ideal” process.

Modeling and optimization of extracellular polysaccharides production by Enterobacter A47

Polysaccharides are gaining increasing attention as potential environmental friendly and sustainable building blocks in many fields of the (bio)chemical industry. The microbial production of polysaccharides is envisioned as a promising path, since higher biomass growth rates are possible and therefore higher productivities may be achieved compared to vegetable or animal polysaccharides sources. This Ph.D. thesis focuses on the modeling and optimization of a particular microbial polysaccharide, namely the production of extracellular polysaccharides (EPS) by the bacterial strain Enterobacter A47. Enterobacter A47 was found to be a metabolically versatile organism in terms of its adaptability to complex media, notably capable of achieving high growth rates in media containing glycerol byproduct from the biodiesel industry. However, the industrial implementation of this production process is still hampered due to a largely unoptimized process. Kinetic rates from the bioreactor operation are heavily dependent on operational parameters such as temperature, pH, stirring and aeration rate. The increase of culture broth viscosity is a common feature of this culture and has a major impact on the overall performance. This fact complicates the mathematical modeling of the process, limiting the possibility to understand, control and optimize productivity. In order to tackle this difficulty, data-driven mathematical methodologies such as Artificial Neural Networks can be employed to incorporate additional process data to complement the known mathematical description of the fermentation kinetics. In this Ph.D. thesis, we have adopted such an hybrid modeling framework that enabled the incorporation of temperature, pH and viscosity effects on the fermentation kinetics in order to improve the dynamical modeling and optimization of the process. A model-based optimization method was implemented that enabled to design bioreactor optimal control strategies in the sense of EPS productivity maximization. It is also critical to understand EPS synthesis at the level of the bacterial metabolism, since the production of EPS is a tightly regulated process. Methods of pathway analysis provide a means to unravel the fundamental pathways and their controls in bioprocesses. In the present Ph.D. thesis, a novel methodology called Principal Elementary Mode Analysis (PEMA) was developed and implemented that enabled to identify which cellular fluxes are activated under different conditions of temperature and pH. It is shown that differences in these two parameters affect the chemical composition of EPS, hence they are critical for the regulation of the product synthesis. In future studies, the knowledge provided by PEMA could foster the development of metabolically meaningful control strategies that target the EPS sugar content and oder product quality parameters.

Ethical leadership and reputation: Combined indirect effects on organizational deviance

This is a pre-copyedited, author-produced PDF of an article accepted for publication in Journal of Business Ethics following peer review. The version of record Neves, P., & Story, J. (2015). Ethical Leadership and Reputation: Combined Indirect Effects on Organizational Deviance. Journal of Business Ethics, 127(1), 165–176. “The final publication is available at Springer via http://dx.doi.org/10.1007/s10551-013-1997-3”.

How servant leadership is perceiver by leaders and followers in a Portuguese organizational context

Servant leadership theory has been the subject of great academic discussion, namely in what concerns reaching a consensus for its definition. As many frameworks have been designed in order to define the servant leader’s characteristics, we based ourselves in van Dierendonck’s review and synthesis on servant leadership (2011) to assess how it is perceived in a Portuguese organizational context. After performing several interviews in a private health care organization, we conclude that the perception of servant leadership is generally positive and that its characteristics seem to be in line with academic literature. However, some issues arose such as a seemingly lack of relevance given to authenticity and humility, the latter being a unique attribute of servant leadership. Also, we found a discrepancy between hierarchical levels’ perception of servant leadership characteristics as well as questioning if an over emphasis on service can diminish the servant leader’s impact on organizational performance.

Critical incident study on forgiveness in the organizational context

Forgiveness has been subject of interest, mainly in the psychology fields of study. Relatively to the organizational context, this topic has been somehow put aside and settled as something that is purely an intra-individual phenomenon which organizations cannot force, or even stimulate. As conflicts are common within organizations and being often difficult to overcome, eyes have turned into the role forgiveness might take in this scenario. Despite forgiveness being accepted as an intrapersonal decision and a result of predisposition as it is a result of education and culture. This study, as some already done, refuses to accept forgiveness as an unchangeable behavior that cannot be manipulated or induced by managers or by organizational context. Therefore, offering a set of incidents as well as their classification, that have been identified by individuals performing different types organizational roles in different organization which is believed as being a genuine way of delivering to the reader a set of actions and behaviors that if taken, may incentivize or inhibit forgiveness.

Perception of organizational politics and the effect of authenticity and affective commitment on deviance and task performance in contact centers

This study aimed to understand employees’ reactions to organizational politics in Contact Centers. Drawing from a sample of 187 supervisor-employee dyads, we studied the relationship between employees’ perceptions of organizational politics and supervisor-rated task performance and deviance, and mediation effects by authenticity at work and affective commitment. Results indicate that workers tend to react to workplace politics with deviant behavior and worse task performance. We found that the relationship between perceived politics and task performance was mediated by authenticity. The relationship between perceived politics and supervisor-rated deviance was mediated by affective commitment to the organization. Implications for management are discussed.

Does companionate love express itself unequally in different organizational forms (private companies, hybrid and non-governmental organizations)?

Although, the word “Love” in organizations is seen as a rare concept, but it has gained importance in management theoretical foundation. This study seeks to explore the companionate love in distinct of organizational forms (Private companies; Social organizations; NGO and IPSS) through interviews. The results propose that it is a tensional concept with a complex dynamic: tension of personal behavior, tension of professional behavior; tension of individual impact and tension of community impact. The love dynamic has common points to all organizations, but its expression depends on the specific form of the organization.

The reasonant influence of supply chain management practices on organizational performance

A single supply chain management (SCM) practice will have a certain impact on organizational performance(OP). However, since it is placed in a system that many other practices are conducted simultaneously, the practice itself will interact with other ones and have a greater impact on OP. This mechanism is named the "resonant" influence. The technique of Structural equation modelling (SEM) was used to test the above mechanism with data collected from Vietnamese garment enterprises. The tcst results showed that the model without mutual interaction among SCM practices could explain 42.8%, 26.3% and 34% variance of operational performance, customer satisfaction and financial performance. While the one containing this interaction is capable to explain 69.5%, 33.1% and 57.3%, respectively.