933 resultados para Weak focus of third order
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The rise of new multinationals in countries like Brazil provides an opportunity to revisit and carefully construct theories of how firms internationalize, a topic on which extant theory is weak. Brazilian firms are "infant multinationals", unlike developed country firms that are "mature multinationals". They are also internationalizing in a very different global context, and can do so on the basis of different competitive advantages than multinationals that came before. Therefore, this study aims at creating subsidies for theory building about early-stage internationalization. Emerging country firms have Production competences as main competitive asset to internationalize, what reflects their competitive positioning in home markets and their entry strategy in international markets. In the case of early-entrants - Western multinationals in the 1950s and Japanese in the 1980s - the Production competence played a key role for successful internationalization. Thus, the focus of the study is the role that the Production competence plays in the internationalization of late-entrants, the emerging country multinationals. The research design considers not only the position of the headquarters but also the initiatives of the subsidiaries and the dynamic interplay between both. The paper allows a better understanding of internationalization processes and the role of Production, when firms start building their own international networks. It brings relevant insights about the paths that are being followed by emerging country multinationals, the difficulties they find, the solutions they develop. These are important inputs not only for new theory building but also for managerial practice. (C) 2012 Elsevier B.V. All rights reserved.
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Protozoan parasites cause thousands of deaths each year in developing countries. The genome projects of these parasites opened a new era in the identification of therapeutic targets. However, the putative function could be predicted for fewer than half of the protein-coding genes. In this work, all Trypanosoma cruzi proteins containing predicted transmembrane spans were processed through an automated computational routine and further analyzed in order to assign the most probable function. The analysis consisted of dissecting the whole predicted protein in different regions. More than 5,000 sequences were processed, and the predicted biological functions were grouped into 19 categories according to the hits obtained after analysis. One focus of interest, due to the scarce information available on trypanosomatids, is the proteins involved in signal-transduction processes. In the present work, we identified 54 proteins belonging to this group, which were individually analyzed. The results show that by means of a simple pipeline it was possible to attribute probable functions to sequences annotated as coding for "hypothetical proteins.'' Also, we successfully identified the majority of candidates participating in the signal-transduction pathways in T. cruzi.
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This work reports on emissions of unburned hydrocarbon species from batch combustion of fixed beds of coal, sugar-cane bagasse, and blends thereof in a pre-heated two-stage laboratory furnace operated in the temperature range of 800-1000 degrees C. The effects of fuel blending, combustion staging, and operating furnace temperatures on emissions of pollutants were assessed. Furnace effluents were analyzed for products of incomplete combustion (PICs) including CO, volatile and semi-volatile hydrocarbons, and particulate matter, as has been reported in Ref. [1]. Emitted unburned hydrocarbons include traces of potentially health-hazardous Polycyclic Aromatic Hydrocarbons (PAHs), which are the focus of this work. Under the batch combustion conditions implemented herein, PAH were only generated during the volatile combustion phase of the fuels. The most prevalent species were in descending order: naphthalene, acenaphthylene, phenanthrene, fluoranthene, pyrene, dibenzofuran, benzofuran, byphenyl, fluorene, 9H-fluoren-9-one, acephenantrylene, benzo[b] fluoranthene, 1-methyl-naphthalene; 2-methyl-naphthalene, benz[a] anthracene and benzo[a] pyrene. PAH yields were the highest from combustion of neat bagasse. Combustion of the blends resulted in lower yields of PAH, than combustion of either of their neat fuel constituents. Increasing the furnace operating temperature enhanced the PAH emissions from bagasse, but had little effect on those from the coal or from the blends. Flue gas treatment in a secondary-stage furnace, upon with additional air, typically reduced PAH yields by promoting oxidation of the primary-stage furnace effluents. (C) 2011 Elsevier Ltd. All rights reserved.
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The purpose of this study is to present a position based tetrahedral finite element method of any order to accurately predict the mechanical behavior of solids constituted by functionally graded elastic materials and subjected to large displacements. The application of high-order elements makes it possible to overcome the volumetric and shear locking that appears in usual homogeneous isotropic situations or even in non-homogeneous cases developing small or large displacements. The use of parallel processing to improve the computational efficiency, allows employing high-order elements instead of low-order ones with reduced integration techniques or strain enhancements. The Green-Lagrange strain is adopted and the constitutive relation is the functionally graded Saint Venant-Kirchhoff law. The equilibrium is achieved by the minimum total potential energy principle. Examples of large displacement problems are presented and results confirm the locking free behavior of high-order elements for non-homogeneous materials. (C) 2011 Elsevier B.V. All rights reserved.
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Some superlinear fourth order elliptic equations are considered. A family of solutions is proved to exist and to concentrate at a point in the limit. The proof relies on variational methods and makes use of a weak version of the Ambrosetti-Rabinowitz condition. The existence and concentration of solutions are related to a suitable truncated equation. (C) 2012 Elsevier Inc. All rights reserved.
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We study a strongly interacting "quantum dot 1" and a weakly interacting "dot 2" connected in parallel to metallic leads. Gate voltages can drive the system between Kondo-quenched and non-Kondo free-moment phases separated by Kosterlitz-Thouless quantum phase transitions. Away from the immediate vicinity of the quantum phase transitions, the physical properties retain signatures of first-order transitions found previously to arise when dot 2 is strictly noninteracting. As interactions in dot 2 become stronger relative to the dot-lead coupling, the free moment in the non-Kondo phase evolves smoothly from an isolated spin-one-half in dot 1 to a many-body doublet arising from the incomplete Kondo compensation by the leads of a combined dot spin-one. These limits, which feature very different spin correlations between dot and lead electrons, can be distinguished by weak-bias conductance measurements performed at finite temperatures.
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Fetal tissues are frequently discarded before (amniocentesis) or after birth, which both facilitates stem cell access and helps to overcome ethical concerns. In the present study, we aimed to isolate and characterize stem cells from the allantoic and amniotic fluids (ALF; AMF) of third trimester canine fetuses. This gestation age has not been previously explored for stem cells isolation. The gestational age, cell culture conditions and method of isolation used in this study allowed for the establishment and efficient expansion of ALF and AMF cells. We showed that the majority of ALF and ALF cells express the stem cell markers, such as vimentin, nestin and cytokeratin 18 (CK18). Under appropriate culture conditions AMF derived cells can undergo differentiation into osteogenic, adipogenic, chondrogenic and neuron-like lineages. ALF derived cells showed adipogenic, and chondrogenic potential. Therefore, ALF and AMF cells derived at the third gestation trimester can be qualified as progenitor stem cells, accordingly referred as (alantoic fluid progenitor/stem) ALF PS cells and (amniotic fluid progenitor/stem) AMF PS cells. (C) 2012 Elsevier Ltd. All rights reserved.
Benefits of Combinations of Vitamin A, C and E Derivatives in the Stability of Cosmetic Formulations
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Chemically stable ester derivatives of vitamins A, C and E have become a focus of interest for their role in the satisfactory results in skin aging treatments. Accordingly, the aim of this study was to evaluate the physical and chemical stability of a cosmetic formulation containing 1% retinyl palmitate, ascorbyl tetraisopalmitate and tocopheryl acetate, alone or in combination. In the studies of physical stability, a Brookfield rheometer was used to determine rheological behavior of formulations containing the vitamins. Chemical stability was determined by HPLC on a Shimadzu system with UV detection. Results showed that formulations had pseudoplastic behavior and that vitamins did not alter their apparent viscosity and thixotropy. In the chemical stability studies, first-order reaction equations were used for determinations of the shelf-life of vitamins derivatives considering a remaining concentration of 85%. Combined vitamins in a single formulation had a slightly lower degradation rate as compared to different preparations containing only one of the vitamins. Considering that many cosmetic formulations contain vitamin combinations it is suggested that the present study may contribute to the development of more stable formulations containing liposoluble vitamins.
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A nonlinear analysis is performed for the purpose of identification of the pitch freeplay nonlinearity and its effect on the type of bifurcation of a two degree-of-freedom aeroelastic system. The databases for the identification are generated from experimental investigations of a pitch-plunge rigid airfoil supported by a nonlinear torsional spring. Experimental data and linear analysis are performed to validate the parameters of the linearized equations. Based on the periodic responses of the experimental data which included the flutter frequency and its third harmonics, the freeplay nonlinearity is approximated by a polynomial expansion up to the third order. This representation allows us to use the normal form of the Hopf bifurcation to characterize the type of instability. Based on numerical integrations, the coefficients of the polynomial expansion representing the freeplay nonlinearity are identified. Published by Elsevier Ltd.
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We investigate the occurrence of the optical Kerr effect and two-photon absorption when an oil-based magnetic Fe3O4 nanoparticles colloidal suspension is illuminated with high intensity femtosecond laser pulses. The frequency of the pulses is controlled and the Z-scan technique is employed in our measurements of the nonlinear optical Kerr coefficient (n(2)) and two-photon absorption coefficient (beta). From these values it was possible to calculate the real and imaginary parts of the third-order susceptibility. We observed that increasing the pulse frequency, additional physical processes take place, increasing artificially the absolute values of n(2) and beta. The experimental conditions are discussed to assure the obtention of reliable values of these nonlinear optical parameters, which may be useful in all-optical switching and optical power limiting applications. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4723829]
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The nonlinear index of refraction (n(2)) and the two-photon absorption coefficient (beta) of water-based ferrofluids made of magnetite nanocrystals of different sizes and with different coatings have been measured through the Z-scan technique, with ultrashort (femtoseconds) laser pulses. Their third-order susceptibility is calculated from the values of n(2) and beta. The influence of different particles' coatings and sizes on these nonlinear optical properties are investigated. The values of n(2) and beta depend more significantly on the nanoparticles' size than on the particular coating. We observe a decrease of beta as the nanoparticles' diameters decrease, although the optical gap is found to be the same for all samples. The results are interpreted considering modifications in the electronic orbital shape due to the particles' nanosize effect.
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Abstract Background The study and analysis of gene expression measurements is the primary focus of functional genomics. Once expression data is available, biologists are faced with the task of extracting (new) knowledge associated to the underlying biological phenomenon. Most often, in order to perform this task, biologists execute a number of analysis activities on the available gene expression dataset rather than a single analysis activity. The integration of heteregeneous tools and data sources to create an integrated analysis environment represents a challenging and error-prone task. Semantic integration enables the assignment of unambiguous meanings to data shared among different applications in an integrated environment, allowing the exchange of data in a semantically consistent and meaningful way. This work aims at developing an ontology-based methodology for the semantic integration of gene expression analysis tools and data sources. The proposed methodology relies on software connectors to support not only the access to heterogeneous data sources but also the definition of transformation rules on exchanged data. Results We have studied the different challenges involved in the integration of computer systems and the role software connectors play in this task. We have also studied a number of gene expression technologies, analysis tools and related ontologies in order to devise basic integration scenarios and propose a reference ontology for the gene expression domain. Then, we have defined a number of activities and associated guidelines to prescribe how the development of connectors should be carried out. Finally, we have applied the proposed methodology in the construction of three different integration scenarios involving the use of different tools for the analysis of different types of gene expression data. Conclusions The proposed methodology facilitates the development of connectors capable of semantically integrating different gene expression analysis tools and data sources. The methodology can be used in the development of connectors supporting both simple and nontrivial processing requirements, thus assuring accurate data exchange and information interpretation from exchanged data.
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Máster en Economía del Turismo, Transporte y Medio Ambiente
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It is not unknown that the evolution of firm theories has been developed along a path paved by an increasing awareness of the organizational structure importance. From the early “neoclassical” conceptualizations that intended the firm as a rational actor whose aim is to produce that amount of output, given the inputs at its disposal and in accordance to technological or environmental constraints, which maximizes the revenue (see Boulding, 1942 for a past mid century state of the art discussion) to the knowledge based theory of the firm (Nonaka & Takeuchi, 1995; Nonaka & Toyama, 2005), which recognizes in the firm a knnowledge creating entity, with specific organizational capabilities (Teece, 1996; Teece & Pisano, 1998) that allow to sustaine competitive advantages. Tracing back a map of the theory of the firm evolution, taking into account the several perspectives adopted in the history of thought, would take the length of many books. Because of that a more fruitful strategy is circumscribing the focus of the description of the literature evolution to one flow connected to a crucial question about the nature of firm’s behaviour and about the determinants of competitive advantages. In so doing I adopt a perspective that allows me to consider the organizational structure of the firm as an element according to which the different theories can be discriminated. The approach adopted starts by considering the drawbacks of the standard neoclassical theory of the firm. Discussing the most influential theoretical approaches I end up with a close examination of the knowledge based perspective of the firm. Within this perspective the firm is considered as a knowledge creating entity that produce and mange knowledge (Nonaka, Toyama, & Nagata, 2000; Nonaka & Toyama, 2005). In a knowledge intensive organization, knowledge is clearly embedded for the most part in the human capital of the individuals that compose such an organization. In a knowledge based organization, the management, in order to cope with knowledge intensive productions, ought to develop and accumulate capabilities that shape the organizational forms in a way that relies on “cross-functional processes, extensive delayering and empowerment” (Foss 2005, p.12). This mechanism contributes to determine the absorptive capacity of the firm towards specific technologies and, in so doing, it also shape the technological trajectories along which the firm moves. After having recognized the growing importance of the firm’s organizational structure in the theoretical literature concerning the firm theory, the subsequent point of the analysis is that of providing an overview of the changes that have been occurred at micro level to the firm’s organization of production. The economic actors have to deal with challenges posed by processes of internationalisation and globalization, increased and increasing competitive pressure of less developed countries on low value added production activities, changes in technologies and increased environmental turbulence and volatility. As a consequence, it has been widely recognized that the main organizational models of production that fitted well in the 20th century are now partially inadequate and processes aiming to reorganize production activities have been widespread across several economies in recent years. Recently, the emergence of a “new” form of production organization has been proposed both by scholars, practitioners and institutions: the most prominent characteristic of such a model is its recognition of the importance of employees commitment and involvement. As a consequence it is characterized by a strong accent on the human resource management and on those practices that aim to widen the autonomy and responsibility of the workers as well as increasing their commitment to the organization (Osterman, 1994; 2000; Lynch, 2007). This “model” of production organization is by many defined as High Performance Work System (HPWS). Despite the increasing diffusion of workplace practices that may be inscribed within the concept of HPWS in western countries’ companies, it is an hazard, to some extent, to speak about the emergence of a “new organizational paradigm”. The discussion about organizational changes and the diffusion of HPWP the focus cannot abstract from a discussion about the industrial relations systems, with a particular accent on the employment relationships, because of their relevance, in the same way as production organization, in determining two major outcomes of the firm: innovation and economic performances. The argument is treated starting from the issue of the Social Dialogue at macro level, both in an European perspective and Italian perspective. The model of interaction between the social parties has repercussions, at micro level, on the employment relationships, that is to say on the relations between union delegates and management or workers and management. Finding economic and social policies capable of sustaining growth and employment within a knowledge based scenario is likely to constitute the major challenge for the next generation of social pacts, which are the main social dialogue outcomes. As Acocella and Leoni (2007) put forward the social pacts may constitute an instrument to trade wage moderation for high intensity in ICT, organizational and human capital investments. Empirical evidence, especially focused on the micro level, about the positive relation between economic growth and new organizational designs coupled with ICT adoption and non adversarial industrial relations is growing. Partnership among social parties may become an instrument to enhance firm competitiveness. The outcome of the discussion is the integration of organizational changes and industrial relations elements within a unified framework: the HPWS. Such a choice may help in disentangling the potential existence of complementarities between these two aspects of the firm internal structure on economic and innovative performance. With the third chapter starts the more original part of the thesis. The data utilized in order to disentangle the relations between HPWS practices, innovation and economic performance refer to the manufacturing firms of the Reggio Emilia province with more than 50 employees. The data have been collected through face to face interviews both to management (199 respondents) and to union representatives (181 respondents). Coupled with the cross section datasets a further data source is constituted by longitudinal balance sheets (1994-2004). Collecting reliable data that in turn provide reliable results needs always a great effort to which are connected uncertain results. Data at micro level are often subjected to a trade off: the wider is the geographical context to which the population surveyed belong the lesser is the amount of information usually collected (low level of resolution); the narrower is the focus on specific geographical context, the higher is the amount of information usually collected (high level of resolution). For the Italian case the evidence about the diffusion of HPWP and their effects on firm performances is still scanty and usually limited to local level studies (Cristini, et al., 2003). The thesis is also devoted to the deepening of an argument of particular interest: the existence of complementarities between the HPWS practices. It has been widely shown by empirical evidence that when HPWP are adopted in bundles they are more likely to impact on firm’s performances than when adopted in isolation (Ichniowski, Prennushi, Shaw, 1997). Is it true also for the local production system of Reggio Emilia? The empirical analysis has the precise aim of providing evidence on the relations between the HPWS dimensions and the innovative and economic performances of the firm. As far as the first line of analysis is concerned it must to be stressed the fundamental role that innovation plays in the economy (Geroski & Machin, 1993; Stoneman & Kwoon 1994, 1996; OECD, 2005; EC, 2002). On this point the evidence goes from the traditional innovations, usually approximated by R&D investment expenditure or number of patents, to the introduction and adoption of ICT, in the recent years (Brynjolfsson & Hitt, 2000). If innovation is important then it is critical to analyse its determinants. In this work it is hypothesised that organizational changes and firm level industrial relations/employment relations aspects that can be put under the heading of HPWS, influence the propensity to innovate in product, process and quality of the firm. The general argument may goes as follow: changes in production management and work organization reconfigure the absorptive capacity of the firm towards specific technologies and, in so doing, they shape the technological trajectories along which the firm moves; cooperative industrial relations may lead to smother adoption of innovations, because not contrasted by unions. From the first empirical chapter emerges that the different types of innovations seem to respond in different ways to the HPWS variables. The underlying processes of product, process and quality innovations are likely to answer to different firm’s strategies and needs. Nevertheless, it is possible to extract some general results in terms of the most influencing HPWS factors on innovative performance. The main three aspects are training coverage, employees involvement and the diffusion of bonuses. These variables show persistent and significant relations with all the three innovation types. The same do the components having such variables at their inside. In sum the aspects of the HPWS influence the propensity to innovate of the firm. At the same time, emerges a quite neat (although not always strong) evidence of complementarities presence between HPWS practices. In terns of the complementarity issue it can be said that some specific complementarities exist. Training activities, when adopted and managed in bundles, are related to the propensity to innovate. Having a sound skill base may be an element that enhances the firm’s capacity to innovate. It may enhance both the capacity to absorbe exogenous innovation and the capacity to endogenously develop innovations. The presence and diffusion of bonuses and the employees involvement also spur innovative propensity. The former because of their incentive nature and the latter because direct workers participation may increase workers commitment to the organizationa and thus their willingness to support and suggest inovations. The other line of analysis provides results on the relation between HPWS and economic performances of the firm. There have been a bulk of international empirical studies on the relation between organizational changes and economic performance (Black & Lynch 2001; Zwick 2004; Janod & Saint-Martin 2004; Huselid 1995; Huselid & Becker 1996; Cappelli & Neumark 2001), while the works aiming to capture the relations between economic performance and unions or industrial relations aspects are quite scant (Addison & Belfield, 2001; Pencavel, 2003; Machin & Stewart, 1990; Addison, 2005). In the empirical analysis the integration of the two main areas of the HPWS represent a scarcely exploited approach in the panorama of both national and international empirical studies. As remarked by Addison “although most analysis of workers representation and employee involvement/high performance work practices have been conducted in isolation – while sometimes including the other as controls – research is beginning to consider their interactions” (Addison, 2005, p.407). The analysis conducted exploiting temporal lags between dependent and covariates, possibility given by the merger of cross section and panel data, provides evidence in favour of the existence of HPWS practices impact on firm’s economic performance, differently measured. Although it does not seem to emerge robust evidence on the existence of complementarities among HPWS aspects on performances there is evidence of a general positive influence of the single practices. The results are quite sensible to the time lags, inducing to hypothesize that time varying heterogeneity is an important factor in determining the impact of organizational changes on economic performance. The implications of the analysis can be of help both to management and local level policy makers. Although the results are not simply extendible to other local production systems it may be argued that for contexts similar to the Reggio Emilia province, characterized by the presence of small and medium enterprises organized in districts and by a deep rooted unionism, with strong supporting institutions, the results and the implications here obtained can also fit well. However, a hope for future researches on the subject treated in the present work is that of collecting good quality information over wider geographical areas, possibly at national level, and repeated in time. Only in this way it is possible to solve the Gordian knot about the linkages between innovation, performance, high performance work practices and industrial relations.
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Research in art conservation has been developed from the early 1950s, giving a significant contribution to the conservation-restoration of cultural heritage artefacts. In fact, only through a profound knowledge about the nature and conditions of constituent materials, suitable decisions on the conservation and restoration measures can thus be adopted and preservation practices enhanced. The study of ancient artworks is particularly challenging as they can be considered as heterogeneous and multilayered systems where numerous interactions between the different components as well as degradation and ageing phenomena take place. However, difficulties to physically separate the different layers due to their thickness (1-200 µm) can result in the inaccurate attribution of the identified compounds to a specific layer. Therefore, details can only be analysed when the sample preparation method leaves the layer structure intact, as for example the preparation of embedding cross sections in synthetic resins. Hence, spatially resolved analytical techniques are required not only to exactly characterize the nature of the compounds but also to obtain precise chemical and physical information about ongoing changes. This thesis focuses on the application of FTIR microspectroscopic techniques for cultural heritage materials. The first section is aimed at introducing the use of FTIR microscopy in conservation science with a particular attention to the sampling criteria and sample preparation methods. The second section is aimed at evaluating and validating the use of different FTIR microscopic analytical methods applied to the study of different art conservation issues which may be encountered dealing with cultural heritage artefacts: the characterisation of the artistic execution technique (chapter II-1), the studies on degradation phenomena (chapter II-2) and finally the evaluation of protective treatments (chapter II-3). The third and last section is divided into three chapters which underline recent developments in FTIR spectroscopy for the characterisation of paint cross sections and in particular thin organic layers: a newly developed preparation method with embedding systems in infrared transparent salts (chapter III-1), the new opportunities offered by macro-ATR imaging spectroscopy (chapter III-2) and the possibilities achieved with the different FTIR microspectroscopic techniques nowadays available (chapter III-3). In chapter II-1, FTIR microspectroscopy as molecular analysis, is presented in an integrated approach with other analytical techniques. The proposed sequence is optimized in function of the limited quantity of sample available and this methodology permits to identify the painting materials and characterise the adopted execution technique and state of conservation. Chapter II-2 describes the characterisation of the degradation products with FTIR microscopy since the investigation on the ageing processes encountered in old artefacts represents one of the most important issues in conservation research. Metal carboxylates resulting from the interaction between pigments and binding media are characterized using synthesised metal palmitates and their production is detected on copper-, zinc-, manganese- and lead- (associated with lead carbonate) based pigments dispersed either in oil or egg tempera. Moreover, significant effects seem to be obtained with iron and cobalt (acceleration of the triglycerides hydrolysis). For the first time on sienna and umber paints, manganese carboxylates are also observed. Finally in chapter II-3, FTIR microscopy is combined with further elemental analyses to characterise and estimate the performances and stability of newly developed treatments, which should better fit conservation-restoration problems. In the second part, in chapter III-1, an innovative embedding system in potassium bromide is reported focusing on the characterisation and localisation of organic substances in cross sections. Not only the identification but also the distribution of proteinaceous, lipidic or resinaceous materials, are evidenced directly on different paint cross sections, especially in thin layers of the order of 10 µm. Chapter III-2 describes the use of a conventional diamond ATR accessory coupled with a focal plane array to obtain chemical images of multi-layered paint cross sections. A rapid and simple identification of the different compounds is achieved without the use of any infrared microscope objectives. Finally, the latest FTIR techniques available are highlighted in chapter III-3 in a comparative study for the characterisation of paint cross sections. Results in terms of spatial resolution, data quality and chemical information obtained are presented and in particular, a new FTIR microscope equipped with a linear array detector, which permits reducing the spatial resolution limit to approximately 5 µm, provides very promising results and may represent a good alternative to either mapping or imaging systems.