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The catalytic step that initiates formation of the ferric oxy-hydroxide mineral core in the central cavity of H-type ferritin involves rapid oxidation of ferrous ion by molecular oxygen (ferroxidase reaction) at a binuclear site (ferroxidase site) found in each of the 24 subunits. Previous investigators have shown that the first detectable reaction intermediate of the ferroxidase reaction is a diferric-peroxo intermediate, F-peroxo, formed within 25 ms, which then leads to the release of H2O2 and formation of ferric mineral precursors. The stoichiometric relationship between F-peroxo, H2O2, and ferric mineral precursors, crucial to defining the reaction pathway and mechanism, has now been determined. To this end, a horseradish peroxidase-catalyzed spectrophotometric method was used as an assay for H2O2. By rapidly mixing apo M ferritin from frog, Fe2+, and O-2 and allowing the reaction to proceed for 70 ms when F-peroxo has reached its maximum accumulation, followed by spraying the reaction mixture into the H2O2 assay solution, we were able to quantitatively determine the amount of H2O2 produced during the decay of F-peroxo. The correlation between the amount of H2O2 released with the amount of F-peroxo accumulated at 70 ms determined by Mossbauer spectroscopy showed that F-peroxo decays into H2O2 with a stoichiometry of 1 F-peroxo:H2O2. When the decay of F-peroxo was monitored by rapid freeze-quench Mossbauer spectroscopy, multiple diferric mu-oxo/mu-hydroxo complexes and small polynuclear ferric clusters were found to form at rate constants identical to the decay rate of F-peroxo. This observed parallel formation of multiple products (H2O2, diferric complexes, and small polynuclear clusters) from the decay of a single precursor (F-peroxo) provides useful mechanistic insights into ferritin mineralization and demonstrates a flexible ferroxidase site.

The catalytic step that initiates formation of the ferric oxy-hydroxide mineral core in the central cavity of H-type ferritin involves rapid oxidation of ferrous ion by molecular oxygen (ferroxidase reaction) at a binuclear site (ferroxidase site) found in each of the 24 subunits. Previous investigators have shown that the first detectable reaction intermediate of the ferroxidase reaction is a diferric-peroxo intermediate, F(peroxo), formed within 25 ms, which then leads to the release of H(2)O(2) and formation of ferric mineral precursors. The stoichiometric relationship between F(peroxo), H(2)O(2), and ferric mineral precursors, crucial to defining the reaction pathway and mechanism, has now been determined. To this end, a horseradish peroxidase-catalyzed spectrophotometric method was used as an assay for H(2)O(2). By rapidly mixing apo M ferritin from frog, Fe(2+), and O(2) and allowing the reaction to proceed for 70 ms when F(peroxo) has reached its maximum accumulation, followed by spraying the reaction mixture into the H(2)O(2) assay solution, we were able to quantitatively determine the amount of H(2)O(2) produced during the decay of F(peroxo). The correlation between the amount of H(2)O(2) released with the amount of F(peroxo) accumulated at 70 ms determined by Mossbauer spectroscopy showed that F(peroxo) decays into H(2)O(2) with a stoichiometry of 1 F(peroxo):H(2)O(2). When the decay of F(peroxo) was monitored by rapid freeze-quench Mossbauer spectroscopy, multiple diferric mu-oxo/mu-hydroxo complexes and small polynuclear ferric clusters were found to form at rate constants identical to the decay rate of F(peroxo). This observed parallel formation of multiple products (H(2)O(2), diferric complexes, and small polynuclear clusters) from the decay of a single precursor (F(peroxo)) provides useful mechanistic insights into ferritin mineralization and demonstrates a flexible ferroxidase site.

The results presented in this article are related to the field of investigation defined inside the European TSER project on "Information Society, Work and Generation of New Forms of Social Exclusion " (SOWING). The thematic center of the project is connected with the question of the relations that exist between the introduction of information technologies (IT) and the changes in the waged labour as well as in the organisation of work systems. The introduction of these technologies transformed specially the activities on services as well as certain branches, where great changes of the organization of work for the next future assume, which are discussed within the margin of the debate on future forms of work. The tendencies within the occupational structures indicate an individualisation of the insecurities and an opening of the occupational carreers. For these reasons, the development of the occupational carreers is more and more bound to the biographical planning. The institutionalised occupational model is changing very strongly, which in the long term will take to social and cultural changes, not only in the professional life, but also in the private life.

The relation between work organisation and technological practices in auto industry is analysed in this article. The concept of “technological practice” in this sector is used to describe the specific ways of embedding information and communication technology applications into the organizational forms and cultural patterns. This concept was developed with the Sowing project (TSER, DG XII) and that approach included either the shop floor co-operation up to the regionally based networks of companies and supporting institutions. The authors studied different sectors in the automotive firms of different European countries (Germany, Belgium and Portugal): shopfloor and production lines, design and management and the local inter-relationships. It was underlined some evidencies of the different alternatives in terms of technological practices for the same sector. Much of the litterature try to disseminate an idea of a single (and optimum) organisational model for the same type of product. And here, even with the same type of technology, and of product (medium-high range), one can find different models, different cultures, different ways of organising the industrial structure (firms, regional institutions, R&D centres) in the same sector (auto industry).

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Let \(\gamma\) be a simple open smooth curve and \(\alpha\) be an orientation-preserving diffeomorphism of \(\gamma\) onto itself which has only two fixed points. Criteria for one-sided invertibility of the functional operator
\[
A=aI-bW,
\]
where \(a\) and \(b\) are continuous functions, \(I\) is the identity operator, \(W\) is the shift operator: \((Wf)(t)=f[\alpha(t)]\), in a reflexive rearrangement-invariant space of fundamental type \(X(\gamma)\) with nontrivial Boyd indices, are obtained.

In this paper we deal with the interpolation from Lebesgue spaces \(L^p\) and \(L^q\), into an Orlicz space \(L^\varphi\), where \( 1 \le p < q \le \infty \) and \(\varphi^{-1}(t)=t^{1/p}\rho(t^{1/q-1/p})\) for some concave function \(\rho\), with the special attention to the interpolation constant \(C\). For a bounded linear operator \(T\) in \(L^p\) and \(L^q\), we prove modular inequalities, which allow us to get the estimate, for both, the Orlicz norm and the Luxemburg norm,
\[
\|T\|_{L^\varphi\to L^\varphi}
\le C\max\Big\{
\|T\|_{L^p\to L^p},
\|T\|_{L^q\to L^q}
\Big\},
\]
where the interpolation constant \(C\) depends only on \(p\) and \(q\). We give estimates for \(C\), which imply \(C<4\). Moreover, if either \( 1 < p < q \le 2\) or \( 2 \le p < q < \infty\), then \(C< 2\). If \(q=\infty\), then \(C\le 2^{1-1/p}\), and, in particular, for the case \(p=1\) this gives the classical Orlicz interpolation theorem with the constant \(C=1\).

The practical implantation of the concept of dynamic virtual enterprise is still far from expectations due to a number of factors such as the lack of appropriate interoperable infrastructures and tools, lack of common ontology, and the socio-organizational difficulties. However, the creation of industry clusters supported by advanced information and communication tools can meanwhile provide a basis for the rapid creation of dynamic virtual enterprises in response to the market opportunities. A federated service management approach is introduced in this context and its application to the tourism industry is discussed. Finally, the support for the aggregation of simpler services into value-added services, implemented by distributed business processes within different organizations, is presented.

Measurements of electron impact ionization of neutral Al, Ga, and In show large cross sections compared to other elements in the same rows of the periodic table. Semiempirical and classical calculations of direct ionization cross sections are all substantially smaller. Calculations by McGuire [Phys. Rev. A 26, 125 (1982)] for aluminum that include excitations to autoionizing 3s3p2 doublet levels are 2.5 times higher than experiment at the peak. We report the direct ionization cross sections based on the binary-encounter-Bethe model of Kim and Rudd [Phys. Rev. A 50, 3954 (1994)], which is an ab initio theory. We add the autoionization contribution using scaled plane-wave Born cross sections as recently developed by Kim [Phys. Rev. A 64, 032713 (2001)] for excitations to the first set of autoionizing levels. Dirac-Fock wave functions are used for the atomic structure. Our results are in excellent agreement with experimental values and support substantial contributions from excitation-autoionization to the total ionization cross sections for these elements. We also compare the total ionization cross section of boron to available theories, though no experimental data are available.

The outcome of O-2 activation at the diiron(II) cluster in the R2 subunit of Escherichia coli (class I) ribonucleotide reductase has been rationally altered from the normal tyrosyl radical (Y122)(1) production to self-hydroxylation of a phenylalanine side-chain by two amino acid substitutions that leave intact the (histidine)(2)-(carboxylate)(4) ligand set characteristic of the diiron-carboxylate family. Iron ligand Asp (D) 84 was replaced with Glu (E), the amino acid found in the cognate position of the structurally similar diiron-carboxylate protein, methane monooxygenase hydroxylase (MMOH). We previously showed that this substitution allows accumulation of a mu -1,2-peroxodiiron(III) intermediate,(2 3) which does not accumulate in the wild-type (wt) protein and is probably a structural homologue of intermediate P (H-peroxo) in O-2 activation by MMOH.(4) In addition, the near-surface residue Trp (W) 48 was replaced with Phe (F), blocking transfer of the "extra" electron that occurs in wt R2 during formation of the formally Fe(LII)Fe(IV) cluster X.(5-7) Decay of the mu1,2-peroxodiiron(III) complex in R2-W38F/D84E gives an initial brown product, which contains very little YI22(.) and which converts very slowly (t(1/2) similar to 7 h) upon incubation at 0 degreesC to an intensely purple final product. X-ray crystallographic analysis of the purple product indicates that F208 has undergone epsilon -hydroxylation and the resulting phenol has shifted significantly to become st ligand to Fe2 of the diiron cluster. Resonance Raman (RR) spectra of the purple product generated with O-16(2) or O-18(2) show appropriate isotopic sensitivity in bands assigned to O-phenyl and Fe-O-phenyl vibrational modes, confirming that the oxygen of the Fe(III)-phenolate species is derived from Or. Chemical analysis, experiments involving interception of the hydroxylating intermediate with exogenous reductant, and Mossbauer and EXAFS characterization of the brown and purple species establish that F208 hydroxylation occurs during decay of the peroxo complex and formation of the initial brown product. The slow transition to the purple Fe(LII)-phenolate species is ascribed to a ligand rearrangement in which mu -O2- is lost and the F208-derived phenolate coordinates. The reprogramming to F208 monooxygenase requires both amino acid substitutions, as very little epsilon -hydroxyphenylalanine is formed and pathways leading to Y122(.) formation predominate in both R2-D84E and R2-W48F(2-7).

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In this paper we extend necessary conditions for Fredholmness of singular integral operators with piecewise continuous coefficients in rearrangement-invariant spaces [K98] to the weighted case \(X(\Gamma,w)\). These conditions are formulated in terms of indices \(\alpha(Q_tw)\) and \(\beta(Q_tw)\) of a submultiplicative function \(Q_tw\), which is associated with local properties of the space, of the curve, and of the weight at the point \(t\Gamma\). Using these results we obtain a lower estimate for the essential norm \(S\) of the Cauchy singular integral operator \(S\) in reflexive weighted rearrangement-invariant spaces \(X(\Gamma, w)\) over arbitrary Carleson curves \(\Gamma\):
\[
|S|\ge\cot(\pi\lambda_{\Gamma,w}/2)
\]
where \(\lambda_{\Gamma,w} :=inf_{t\in\Gamma} min\{\alpha(Q_tw), 1 - \beta(Q_tw)\}\). In some cases we give formulas for computation of \(\alpha(Q_tw)\) and \(\beta(Q_tw)\).

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The socio-economic subsystem encompassing fisheries may be defined as including not only the harvesting sector but also several related activities occurring both upstream (shipbuilding, gear manufacture) and downstream (processing, distribution and trade). But these closely interrelated economic activities can also be set within a much broader system which would include the ecological, institutional and political influences which frame economic behaviour. The value of this broader conceptualisation is that it treats fisheries not as an isolated and independent economic activity but as part of a more holistic and complex system. This broader perspective is of particular significance when attempting to examine the concept of regional dependence. The socio-economic subsystem for fisheries is dominated by small and medium sized enterprises (SMEs). And Peniche emerges as one of Portugal’s most important fishing ports whether measured in terms of the volume of landings or the total numbers of fishermen. It also has one of the highest levels of fisheries dependence of all coastal municipalities in Portugal with over 20% of its workforce currently engaged in fisheries related employment, faces a daunting and uncertain future. The social fabric of fisheries dependent communities also suffers serious damage; once again, the technocratic approach to management has no solutions to offer. It is essential, therefore, to turn away from the existing approach and to develop instead new forms of intervention; in short, to provide a new vision. This implies change not only to the policy process but also in the attitudes of the social actors and in the preoccupations of fisheries related research. An integrated approach is required based on participative action and the development of an integrated information network.

One can assist to significant changes in the organisation of manufacturing systems during the last years. Lean production, network enterprise or the virtual enterprises are reference concepts of the re-organisation of manufacturing systems. Some authors mention a new enterprise paradigm, of generalisation of intelligent manufacture, organised in networks and assisted by information and communication technologies. The first part of the paper develops a critical approach to the illusion connected to these concepts, calling the attention to the diversity of the type of relationships among firms. If virtual enterprises (VE) are networks of firms with intensive usage of ICT, one can verify a predominance of a technicist perspective. This one considers that the development of VEs is a technological problem, of development and management of information systems, and of entrepreneurial share of different databases. Sociology can be useful, even fundamental in an anthropocentric approach. The last part of the paper is on the Portuguese situation in the automobile sector, approaching the types of entrepreneurial organisation.

Formulas for the total ionization cross section by electron impact based on the binary-encounter-dipole (BED) model and its simpler version, the binary-encounter-Bethe (BEB) model are extended to relativistic incident electron energies. Total ionization cross sections for the hydrogen and helium atoms from the new relativistic formulas are compared to experimental data. Relativistic effects double the total ionization cross section of H and He at incident electron energy 300 keV and dominate the cross section thereafter. A simple modification of the original BED-BEB formulas is proposed for applications to ion targets and inner-shell electrons of neutral atoms and molecules. The relativistic and nonrelativistic BEB cross sections are compared to the K-shell ionization cross sections by electron impact for the carbon, argon, nickel, niobium, and silver atoms. For carbon and argon, the relativistic effects are small, and both forms of the BEB cross sections agree well with available experimental data. For the nickel and heavier atoms, the relativistic increase of cross sections becomes noticeable from about 100 keV and higher in the incident electron energy. The empirical formula by Casnati et al. [J. Phys. B 15, 155 (1982)] after correcting for relativistic effects as shown by Quarles [Phys. Rev. A 13, 1278 (1976)] agrees well with the BEB cross sections for light atoms. However, the peak values of the Casnati cross sections become higher than the relativistic BEB peak cross sections as the atomic number increases. The BEB model is also applied to the total ionization cross section of the xenon atom, and the theory agrees well with experiments at low incident electron energies, but disagrees with experiment at relativistic incident energies.

Mycobacterium tuberculosis KatG is a multifunctional heme enzyme responsible for activation of the antibiotic isoniazid. A KatG(S315T) point mutation is found in >50% of isoniazid-resistant clinical isolates. Since isoniazid activation is thought to involve an oxidation reaction, the redox potential of KatG was determined using cyclic voltammetry, square wave voltammetry, and spectroelectrochemical titrations. Isoniazid activation may proceed via a cytochrome P450-like mechanism. Therefore, the possibility that substrate binding by KatG leads to an increase in the heme redox potential and the possibility that KatG(S315T) confers isoniazid resistance by altering the redox potential were examined. Effects of the heme spin state on the reduction potentials of KatG and KatG(S315T) were also determined. Assessment of the Fe3+/Fe2+ couple gave a midpoint potential of ca. -50 mV for both KatG and KatG(S315T). In contrast to cytochrome P450s, addition of substrate had no significant effect on either the KatG or KatG(S315T) redox potential. Conversion of the heme to a low-spin configuration resulted in a -150 to -200 mV shift of the KatG and KatG(S315T) redox potentials. These results suggest that isoniazid resistance conferred by KatG(S315T) is not mediated through changes in the heme redox potential. The redox potentials of isoniazid were also determined using cyclic and square wave voltammetry, and the results provide evidence that the ferric KatG and KatG(S315T) midpoint potentials are too low to promote isoniazid oxidation without formation of a high-valent enzyme intermediate such as compounds I and IT or oxyferrous KatG.

Mycobacterium tuberculosis KatG is a multifunctional heme enzyme responsible for activation of the antibiotic isoniazid. A KatG(S315T) point mutation is found in >50% of isoniazid-resistant clinical isolates. Since isoniazid activation is thought to involve an oxidation reaction, the redox potential of KatG was determined using cyclic voltammetry, square wave voltammetry, and spectroelectrochemical titrations. Isoniazid activation may proceed via a cytochrome P450-like mechanism. Therefore, the possibility that substrate binding by KatG leads to an increase in the heme redox potential and the possibility that KatG(S315T) confers isoniazid resistance by altering the redox potential were examined. Effects of the heme spin state on the reduction potentials of KatG and KatG(S315T) were also determined. Assessment of the Fe3+/Fe2+ couple gave a midpoint potential of ca. -50 mV for both KatG and KatG(S315T). In contrast to cytochrome P450s, addition of substrate had no significant effect on either the KatG or KatG(S315T) redox potential. Conversion of the heme to a low-spin configuration resulted in a -150 to -200 mV shift of the KatG and KatG(S315T) redox potentials. These results suggest that isoniazid resistance conferred by KatG(S315T) is not mediated through changes in the heme redox potential. The redox potentials of isoniazid were also determined using cyclic and square wave voltammetry, and the results provide evidence that the ferric KatG and KatG(S315T) midpoint potentials are too low to promote isoniazid oxidation without formation of a high-valent enzyme intermediate such as compounds I and IT or oxyferrous KatG.

The partly-articulated postcranial remains of two sauropod skeletons recently found in Tang Vay (Savannakhet Province, Laos) are assigned to the species Tangvayosaurus hoffeti (nov. gen., nov. sp.). The derived characters present in the new material confirm the presence of titanosaurs in South East Asia at the end of the Early Cretaceous, but are not consistent with its placement within Titanosaurus genus as first done by Hoffet in 1942. All of the material relative to this species is therefore referred to a new genus: Tangvayosaurus. Tangvayosaurus and the Thai genus Phuwiangosaurus have strong affinities and are considered as primitive titanosaurs.

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Science and technology (S&T) are considered to be a central source, or at least a basic medium, of societal and industrial innovation, while innovation is conceived to basically feed the regeneration of our welfare. The suppliers of S&T in Europe as well as the users of their „products“, are confronted with a number of challenges today. We want to stress here that it was not the primary goal of our Advanced Science & Technology Policy Planning (ASTPP) Network to come up with proposals how the strategic character of European S&T policies could be strengthened. The ASTPP-network instead focuses on one aspect: the provision of strategic intelligence necessary to identify and develop strategic choices. The underlying hypothesis is that the existing body of experiences with technology foresight, technology assessment and S/T policy evaluation provides a basis for the development of an advanced S&T policy „planning“ approach by trying to enhance, interlink or even integrate the growing, but still dispersed experience in these three areas of intelligence. By „intelligent“ we mean that the inter-relatedness of S&T, industrial efforts, societal needs and political interventions becomes more transparent so that interactive collaboration between them will be facilitated.