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A two‐spar cantilever box beam with forty‐five degrees sweep and oblique ribs placed parallel to the root clamping section was the subject of a series of static tests. Stress and strain distributions were determined, primarily in a region distant from the root and tip disturbances, to permit a stringent comparison with three well‐known swept wing theories and the simple theory of bending. Torsional and flexural stiffnesses were also measured and compared with these theories. The sequence of calculation for each method is presented and it is found that two of the theories provide accurate predictions of the stresses, strains and stiffnesses. The influence of rivet slip and rivet flexibility on the stiffnesses of the box is mentioned. As a secondary aim of the investigation, the distribution of normal and shear strain has been measured in the cover skin and spar webs at the root connexion. The design of swept box examined has been the subject of research in a number of establishments and a review of this other work is included.

There are notable indigenous business models in the African context that have either been unexplored or are yet to be highlighted and given due attention at the international level. This chapter provides a cross-case analysis of the indigenous business practices of three ethnic groups across West Africa: Nigeria (Igbos), Ghana (Ewes) and the Benin Republic (Guns), thus viewing business models, from anglophone and francophone perspectives. Specifically, the chapter discusses the apprenticeship models igba-boi, of the Igbo society, dorsorsror, among the Ewes, and eyi alo within the Guns society and succession models in the three societies ‘Inochi anya, domenyinyi and eyi kanta’ respectively, with the aim of highlighting insights for practice, policy and academia. Historically, there have been relevant structures to ensure the transfer of knowledge and wealth to the next generation; this is driven by both cultural and traditional systems of the ethnic groups. The findings show that the family unit plays a significant role in building a sustainable channel, though informal, through which the heritage of business models is attained. To this end, the authors recommend leveraging the unique models of apprenticeship and business succession practised in these ethnic groups to support current policies, such as those relating to Technical and Vocational Education and Training (TVET).

Product mix and the acquisition of the assets needed for their production are interdependent decisions. However, these decisions are frequently evaluated independently of each other and with conceptually different decision models. This article expands activity-based costing (ABC) to incorporate the cost of capital. The resulting model traces the cost of capital to products and thereby measures the economic value added (EVA) from their production. The discounted value of a product’s EVA over its life is equivalent to its net present value (Hartman, 2000; Shrieves & Wachowicz, 2001). The discounted EVA of a product also equals the net present value of the assets used to manufacture the product. Consequently, evaluating products with an ABC model incorporating the cost of capital enables product mix and capital budgeting decisions to be evaluated simultaneously. The article also examines the role of ABC when product mix decisions are made at the product and portfolio levels of the firm’s operations.

We examine the impact of multinational firms (MNEs) on exchange rate pass-through when an MNE engages in Cournot competition with domestic and foreign rivals. The MNE can locate its production for the foreign market domestically — intra-firm trade (IT) — or in the foreign country — international production (IP). In addition to incomplete exchange rate pass-through, we show that an MNE increases the sensitivity of domestic market prices and reduces the sensitivity of foreign market prices to exchange rate movements. Finally, IT prices are more sensitive to exchange rate movements than their IP counterparts and react in the opposite direction.

A common approach to dealing with missing data is to estimate the model on the common subset of data, by necessity throwing away potentially useful data. We derive a new probit type estimator for models with missing covariate data where the dependent variable is binary. For the benchmark case of conditional multinormality we show that our estimator is efficient and provide exact formulae for its asymptotic variance. Simulation results show that our estimator outperforms popular alternatives and is robust to departures from the parametric assumptions adopted in the benchmark case. We illustrate our estimator by examining the portfolio allocation decision of Italian households.

Observations in a dataset are rarely missing at random. One can control for this non-random selection of the data by introducing fixed effects or other nuisance parameters. This chapter deals with consistent estimation the presence of many nuisance parameters. It derives a new orthogonality concept that gives sufficient conditions for consistent estimation of the parameters of interest. It also shows how this orthogonality concept can be used to derive and compare estimators. The chapter then shows how to use the orthogonality concept to derive estimators for unbalanced panels and incomplete data sets (missing data).

A stationary 3D energy‐transport model valid for semiconductor heterostructure devices is derived from a semiclassical Boltznmann equation by the moment method. In addition to the well‐known conservation equations, we obtain original interface conditions, which are essential to have a mathematically well‐posed problem. An appropriate modelling of the physical parameters appearing in the system of equations is proposed for gallium arsenide. The model being written and its particularities mentioned, we present a novel numerical algorithm to solve it. The discretization of the equations is achieved by means of standard and mixed finite element methods. We apply the model and numerical algorithm to simulate a 2D AlGaAs/GaAs MODFET. Comparisons between expenrimental measurements and calculations are carried out. The influence of the modelling of the physical parameters, especially the electron mobility and the energy relaxation time, is noted. The results show the satisfactory behaviour of our model and numerical algorithm when applied to GaAs heterostructure devices.

IN this section we investigate various accurate solutions of the problem of the reinforced panel by using the stress‐function. We are then able to form an idea of the accuracy of the “stringer‐sheet” solution and of the conditions which must be satisfied in order that it may be reasonably accurate for practical purposes.

In this paper, the role of three different types of competences in the labour market for higher education graduates is investigated. The article distinguishes discipline‐specific competences, general academic competences and management competences, the first being an example of competences acquired at school, which are of direct use in the labour market, the second being a type of competences also acquired in school, but which fulfil an indirect role by facilitating the acquisition of new competences after graduation from school, and the third, management competences, being an example of competences acquired mainly in a working context and, like discipline‐specific competences, being of direct use in that context. This paper shows that, first, the level of discipline‐specific competences obtained in higher education offers a comparative advantage for graduates working inside the own discipline‐specific domain, and therefore has a pay‐off for those graduates who are able to find a job in this domain; second, the management competences are valued in the labour market but seem to be more likely acquired in a working context than in higher education, and third, the general academic competences acquired in higher education do not pay off directly, but have a significant supportive role when learning competences that have a direct pay‐off in the labour market, like management competences, but are more likely acquired outside education.