On the short-time behavior of the implied volatility for jump-diffusion models with stochastic volatility

In this paper we use Malliavin calculus techniques to obtain an expression for the short-time behavior of the at-the-money implied volatility skew for a generalization of the Bates model, where the volatility does not need to be a diffusion or a Markov process, as the examples in Sect. 7 show. This expression depends on the derivative of the volatility in the sense of Malliavin calculus. E. Alòs’ research is supported by grants MEC FEDER MTM 2006 06427 and SEJ2006-13537. J.A. León’s research is partially supported by the CONACyT grant 45684-F. J. Vives’ research is supported by grant MEC FEDER MTM 2006 06427.     

A learning methodology using Matlab/Simulink for undergraduate electrical engineering courses attending to learner satisfaction outcomes

Learner-centred approaches follow the prevailing tendency in modern University reforms which are primarily concerned about “how people learn”. The methodologies can be learner-centred in the sense of placing the student as the main actor of the teaching–learning process by increasing his interactivity and participation, but also considering what is relevant for the student by measuring the learner satisfaction. In order to promote both aspects, this paper proposes a synchronous software-based active methodology that makes use of the simulations to show a virtual scenario to the students and challenge them to predict and discuss the evolution of the scenario. The proposed methodology improves the visual interface, promotes discussion both among students and with the teacher in a brainstorming stage and shows real-world examples. This software-based methodology has been implemented into an Electric Machinery course at the University of Seville (Spain), and the evaluation has been carried out considering both the affective and cognitive domains. Principal components analysis proves to be useful to highlight the dimensions with a higher influence on learner satisfaction and the affective and cognitive results confirm the successful implementation of the proposal.     

Advantages of assembly lines in Sheltered Work Centres for Disabled. A case study

Current practices for the treatment of the physically and/or mentally handicapped prescribe meaningful job activity as a means towards both a more fulfilling life and societal integration. In many countries, these practices have facilitated the development of many Sheltered Work Centres for Disabled.In the case study presented, a reengineering process is done starting from individual workplaces where only certain workers were capable of assembling the entire product, and finishing with an assembly line implementation. It is revealed how the traditional division of work in single tasks, typical in assembly lines, becomes a perfect tool for making certain worker disabilities invisible, providing new jobs for disabled people; always taking into account certain special constraints that are analysed.     

Optimal investment and production decisions and the value of the firm

We explore the effects of uncertainty on a firm that can respond by modifying its investment or production schedule (or both simultaneously) to variations in output price. Investment may increase capacity and/or reduce costs. We consider a firm with finite resources.Our model uses option theory instead of the more traditional net present value framework. One of the early papers using this approach is Brennan and Schwartz (1985) in which an investment project to extract a finite natural resource is valued. In that paper, the value of the firm is a function of two state variables, the finite resource to be extracted (output to be produced in the future) and the commodity spot price. In order to maximize firm value, the manager can respond by modifying one control variable, the production level. In our model we handle instead three state variables (spot price, resources, accumulated investment) and two control variables (production rate and investment rate), and solve numerically.We obtain both the value and the optimal policy of a firm that has investment projects that increase capacity and/or reduce costs and illustrate optimal policies as resources and available investments decrease over the life of the firm. Firms may start by only investing, then invest and produce, to end only producing.We thank Scott Wo, the referee and the editor for their comments and suggestions. Cortázar and Lowener acknowledge the financial support from FONDECYT and FONDER.     

Trauma epidemiology in Puerto Rico: in-hospital morbidity and mortality from 2002 to 2011

This study aimed to describe the distribution of injury mechanisms and to assess the impact of those mechanisms on the morbidity and mortality of trauma. All patients admitted to Puerto Rico Trauma Hospital (2002–2011) for road-traffic collisions (RTCs, 5,371), gunshot wounds (GSWs, 2,946), falls (2,319), pedestrian accidents (1,652), and stab wounds (SWs, 1,073) were selected. Gunshot victims were 1.19 (95%CI: 1.07–1.33) times as likely as road-traffic victims to have an ISS ≥25. Pedestrians were 1.76 (95%CI: 1.49–2.09) times more likely to have a GCS ≤8 than road-traffic victims were. The risk of dying was 2.64 (95%CI: 2.20–3.16) times higher for gunshot victims and 1.51 (95%CI: 1.23–1.86) times higher for pedestrians compared to patients who had had RTCs. Gunshot victims and pedestrians had the worst clinical outcomes. Accordingly, these patients should receive the most aggressive clinical management. Furthermore, it is imperative to develop public health campaigns on trauma prevention.     

Do online discounts and free gifts damage brand image of service? The moderating role of promotion-proneness

The present paper outlines a study based on an experimental design that investigated the effect of online price discounts and free gifts on consumers’ evaluation of the brand, in the context of an airline. The study also analyzed whether promotion-proneness exercises a moderating effect on this relationship. It was found that discounts generate a more positive brand image than free gifts among promotion-prone users, while for less promotion-prone individuals, the opposite is true. The results will help managers to select the most appropriate online sales promotion type for reaching different consumer groups, depending on their promotion-proneness, in line with the needs and objectives of the service firm.     

Influence of Social Media over the Stock Market

This research analyzes investors’ activity through social media and these media's influence over the Chicago Board Options Exchange Market Volatility Index (VIX) using a logit model and a fuzzy‐set qualitative comparative analysis (fsQCA). The logit results show that social media sentiment influences stock markets. Meanwhile, the fsQCA results show that the investors’ profile is important for explaining how social media influence the stock market. Particularly, holding period combined with experience in technical investors contributes to avoiding a raise in market risk, whereas for nontechnical investors message sentiment and experience form the combination that contributes to avoid a raise in market risk.     

Success factors in a CRM strategy: technology is not all

Organisations today need to create, maintain and reinforce relationships with customers. Customer Relationship Management (CRM) seems to have helped firms to better understand their relationships. However, past studies have looked at technology and customer orientations (COs) as key factors. This paper aims to analyse the simultaneous effect of Market Orientation (MO) (rather than CO), Knowledge Management (KM) and other organisational factors in order to explain how to implement a successful CRM. Findings suggest that MO and KM may influence CRM success. Data also suggest that particular organisational factors such as employees, leadership and specific know-how may be key factors in determining the success of CRM. For efficiency resource management, this paper recommends to focus not as much in technology, but on programmes for selection, training and motivation of employees which may enhance CRM objectives. Companies may also pursue a higher customer value by putting in place and reinforcing KM schemes in specific know-hows about CRM.