Competitive segregation of gallium and indium at heterophase Cu–MnO interfaces studied with transmission electron microscopy

This paper concentrates on the possible segregation of indium and gallium and competitive segregation of gallium and indium at atomically flat parallel {111}-oriented Cu–MnO interfaces. The segregation of gallium at Cu–MnO interfaces after introduction of gallium in the copper matrix of internally oxidized Cu–1 at.%Mn could be hardly detected with energy-dispersive spectrometry in a field emission gun transmission electron microscope. After a heat treatment to dissolve indium in the copper matrix, gallium has a weak tendency to segregate, that is 2.5 at.% Ga per monolayer at the interface compared with 2 at.% in the copper matrix. The striking result is that this gallium segregation is observable because it does not occur at the metal side of the interface but in the first two monolayers at the oxide side. Using the same heat treatment as for introducing indium in the sample, but without indium present, gallium segregates strongly at the oxide side of the Cu–MnO interface with a concentration of about 14.3 at.% in each monolayer of the two. In contrast, the presence of gallium has no influence on the segregation of indium towards Cu–MnO interfaces, because the outermost monolayer at the metal side of the interface contains 17.6 at.% In, that is similar to previously found results. This leads to the intriguing conclusions, firstly, that, in contrast with antimony and indium, gallium segregates at the oxide side of the interface and, secondly, that the presence of indium strongly hampers gallium segregation. The results from analytical transmission electron microscopy on gallium segregation are supported by high-resolution transmission electron microscopy observations.

Genesis of the Floquet Hofstadter butterfly

We investigate theoretically the spectrum of a graphene-like sample (honeycomb lattice) subjected to a perpendicular magnetic field and irradiated by circularly polarized light. This system is studied using the Floquet formalism, and the resulting Hofstadter spectrum is analyzed for different regimes of the driving frequency. For lower frequencies, resonances of various copies of the spectrum lead to intricate formations of topological gaps. In the Landau-level regime, new wing-like gaps emerge upon reducing the driving frequency, thus revealing the possibility of dynamically tuning the formation of the Hofstadter butterfly. In this regime, an effective model may be analytically derived, which allows us to retrace the energy levels that exhibit avoided crossings and ultimately lead to gap structures with a wing-like shape. At high frequencies, we find that gaps open for various fluxes at $E=0$, and upon increasing the amplitude of the driving, gaps also close and reopen at other energies. The topological invariants of these gaps are calculated and the resulting spectrum is elucidated. We suggest opportunities for experimental realization and discuss similarities with Landau-level structures in non-driven systems.Comment: 8 pages, 4 figure

Copper cable theft: revisiting the price–theft hypothesis

Objectives: To test the commonly espoused but little examined hypothesis that fluctuations in the price of metal are associated with changes in the volume of metal theft. Specifically, we analyze the relationship between the price of copper and the number of police recorded 'live’ copper cable thefts from the British railway network (2006 to 2012)

Glucan Phosphatase Variants for Starch Phosphorylation

Glucan phosphatase nucleotide or polypeptide variants of the presently-disclosed subject matter can alter the biophysical properties of starch in vitro or in planta, as well as the total starch biomass production in planta as compared to plants expressing wild-type glucan phosphatases. Plants producing the polypeptide variants of the presently-disclosed subject matter can have increased starch accumulation, increased starched biomass, and/or starch having desired biophysical properties. A method of the presently-disclosed subject matter for producing altered starch includes providing a plant that produces a glucan phosphatase polypeptide variant that comprises an amino acid mutation and collecting starch from the plant

Thermophilic Phosphatases and Methods for Processing Starch Using the Same

The presently-disclosed subject matter includes thermophilic glucan phosphatase polypeptides. In some embodiments the polypeptide includes non-native laforin polypeptides, or fragments and/or variants thereof, and in some instances the polypeptide can alter the biophysical properties of starch in vitro or in planta. The presently-disclosed subject matter also includes isolated polynucleotides encoding the present polypeptides, methods for processing starch by exposing starch to the present polypeptides, and methods for making the present polypeptides

Tuning the atomic and domain structure of epitaxial films of multiferroic BiFeO3

Recent works have shown that the domain walls of room-temperature multiferroic BiFeO3 (BFO) thin films can display distinct and promising functionalities. It is thus important to understand the mechanisms underlying domain formation in these films. High-resolution x-ray diffraction and piezo-force microscopy, combined with first-principles simulations, have allowed us to characterize both the atomic and domain structure of BFO films grown under compressive strain on (001)-SrTiO3, as a function of thickness. We derive a twining model that describes the experimental observations and explains why the 71o domain walls are the ones commonly observed in these films. This understanding provides us with a new degree of freedom to control the structure and, thus, the properties of BiFeO3 thin films.Comment: RevTeX; 4 two-column pages; 4 color figures. Figure 2b does not seem to display well. A proper version can be found in the source fil

Naar een pedagogiek van de tussenwereld : een wijsgerig-pedagogische studie over de grondslagen van de interculturele ontmoeting in opvoeding en onderwijs

One of the oldest and most established terms in education and upbringing is the concept 'innerlife world'. During their education, teachers are taught to 'join' or to 'depart from' the child's innerlife world'. Once they are really practising, they adapt their teaching programmes to this, hoping to approach this world as close as possible. Composers of schoolbooks and teaching methods use the same basic assumption. More recent, but not less established in education and upbringing is the concept interculturality as it is used in terms like 'intercultural education', 'intercultural pedagogy' or 'intercultural method'. By 'acting' intercultural, teachers would be able to cope with the actual situation in the classroom, which migration has made less obvious and more complex. Almost unknown in pedagogy is the term 'interworld' ('in-between world'), although this is exactly the place where the relation between a teacher and a student or an educator and an educated child is being established, which this book will demonstrate. The three concepts mentioned above are the pillars on which this study has been built. The first pillar, the 'innerlife world', is the main issue in the first part. It demonstrates the necessity of disposing of a workable description of the concept 'lived experience' for education and research. Studies into lived experiences are scarce. Both the actual quantity and quality research are missing a consistent concept of what a lived experience is and are therefore unable to reach a veritable insight into the childs' innerlife world. This is especially true for the lived experiences of children of foreign descent (allochthonous), which the autochthonous educator, teacher or researcher might find difficult to understand. To study this complex question in the third part of this study, in order to find a solution to this problem in the next pillar, 'interculturality', we need an in-between step to lead us back to the fundamental problem of pedagogy: knowing the other person. The specific question to which extent an autochthonous person can understand the lived experiences of a person of foreign descent (or the other way around) should be preceded by the conditional question concerning the possibilities of our knowledge of the other person. Speaking from an educational point of view, this question implies a (re)consideration of the educatability of children. In the second part of this study, the main pillar of this book, the introduction of and reflection on the concept 'interworld' bridges the 'innerlife world' treated in the first section and the 'intercultural world', the main theme treated in the third section. 'Intermondiality', which is the basic concept developed on the basis of Merleau-Ponty's philosophical concept 'intermonde' (interworld), relates indeed positively to the concept 'interculturality', which is difficult to describe. It offers possibilities to clear the lived experience of it by educational and upbringing purposes. 1. In order to obtain insight into children's innerlife world,one can use information resulting from previous research. This has been done in the first section of this book: 'research into lived experiences researched'. The meaning given to the concept lived experience determines what the innerlife world looks like. However, in general, the concept 'lived experience' is taken for granted so much that a closer determination or description in social-scientific literature seems unnecessary. To remove all obviousness from the concept 'lived experience', in order to rehabilitate the innerlife world in education and upbringing, the first part of this study will pay attention to the meaning and content of this concept. Only afterwards, we can pass to choosing a suitable method for studying children's lived experiences. A lot of research information is provided by quantitative analysis. Therefore, we will first focus on two quantitative studies into the lived experiences of young people from foreign descent. It shows that researchers do not manage to show how subjective experiences (lived experiences) can be turned into objective experiences (experiences). Objectifying research is being carried out on the basis of a 'natural attitude', in which the world is seen as obvious without preceding reflection on the knowledge of the lived experience of the other person. By adopting this point of view, there is no bewildering, which lays down a condition for and makes access possible to lived experiences: the objective-quantitative method does not provide us insight into children's lived experiences. Hence, it is not suited for studying lived experiences.?For that reason, attention is focused on the more subjective qualitative research method, which was also applied in the tradition of the 'Utrechtse School'. Studies carried out by two educational researchers into children's lived experiences of their living surroundings and disabled children's specific lived experiences were speech making. They apply a method that they call 'phenomenological' but that appears to be no more than a debased reflection of what is normally understood by phenomenology. The considerations that can be considered as conditions to conducting research into lived experience relate, first of all, to the basic philosophical-anthropological question into the scientific conception of researchers operating on a qualitative basis. This presentation of a question should reveal to which extent pedagogic researchers are capable of encountering children. In other words; whether they are willing to recognise the 'problem' of the other one's lived experience as a 'problem'. If one departs from the subjectivity and asks oneself if knowledge is possible, the fact of someone finding someone or something obvious becomes a problem, the 'other one's problem', unlike assuming a 'natural disposition' in which the other one is not regarded upon as a 'problem'. Consequently, reflecting upon the principles of the theory of education and research practices in force concerning children's lived experiences leads to the following area for special attention: which attitude should one adopt in order to get to learn the other one's lived experiences. Qualitative research demands a phenomenological attitude, which is developed as counterpart and supplement of the 'natural attitude' from which one normally operates. Moreover, one should ask oneself the question of the concepts to use: how do researchers into lived experiences use concepts like 'lived experience', 'experience', 'innerlife world' or 'life world'? Neither of both studies carried out in Utrecht does pay enough attention to these conditional presentation of questions. The researchers claim to use an 'anarchistic' scientific conception. However, this perception leaves no place for the child's individuality, that what makes a child a child. This leads to a fake phenomenological research attitude in which researchers place themselves in the centre of interest instead of the children. In an attempt to be one with the children and to adopt an optimistic attitude towards the knowledge of the other, they give up on their adult perspective and ignore the children's innerlife world. By using an inadequate and too large a concept of lived experiences (researchers reduce 'lived experience' to 'tension', 'excitement') one can no longer speak of research into lived experiences in an immediate sense. In order to cope with such shortcomings, we need to determine more precisely the basic concepts 'experience' and 'lived experience'. It is suggested to split up these two concepts and to arrange them, for the time being. This offers the advantage of a more adequate description of the real nature of 'lived experiences'. This reveals two 'worlds', which can be characterised by Dasberg as the limited 'life world' and the unlimited 'innerlife world'. Finally, Langeveld provides a certain context to this limitlessness, which makes it possible to understand the other in his expression of how he or she lives experiences, as in an 'in-between area'. 2. The second section, 'philosophical reflection', is dedicated to the nomination of this area, this 'interworld' that Merleau-Ponty initiated in his philosophy as 'intermonde'. After an introduction treating the consequences of the phenomenological method on conducting research into lived experiences, we will trace how in his early work Merleau-Ponty tried to understand the complete extent of the philosophical 'problem of the other' by a phenomenological analysis of perception. In this study, the other question is raised but Merleau-Ponty does not solve this solipsistic problem completely: solipsism continues to tenaciously exist. However, it indicates the direction in which an eventual solution can be looked for. In the intersubjective encounter people create communicative, physical 'space' which enables a dialogue. For this purpose, Merleau-Ponty introduces the 'intermonde' concept. However, this interworld cannot be described using this method of 'classical' empirical sciences. That is why Merleau-Ponty searches for another, more 'indirect' third way. He finds one in the art of painting, especially in the special way in which Cezanne looked at things and people. This strengthened Merleau-Ponty's believe in the essential importance of 'vibrating transitions' in the transitional area between foreground and background. Such transitions can also be found between people. That is how the existential aspect of art provides an extra dimension to phenomenological philosophy, turning it into ontology. Starting from this new ontological dimension, Merleau-Ponty arrives at a 'topology' of the interworld in his later work, providing the other a place in the 'intermonde' in which I can understand from a?philosophical-anthropological point of view how I should consider that what is different as that what is mine. This insight makes research possible into children's lived experiences of being different. The other one 'being different' is transcended on an ontological level and neutralises the division between the other and me: subjectivity becomes intersubjectivity. This also implies that the other one's cultural-ethnic background does no longer play a part. This ontological aspect provides Merleau-Ponty's intermonde concept with a cultural dimension, what transforms the philosophical 'problem' of te other into an intercultural 'problem'. At this point, we have the possibilities to nominate interculturality as an intermondial phenomenon. Both points of view, the earlier and the later work, are connected by a dissertation on the existential-analytical research method, which can function as a dialogic method in social sciences with the help of a philosophical attitude. The (educational) scientist is also philosopher because of his (inter)subjective interpretation. This insight provides possibilities to look further than the limited boundaries of objectifying methods, like the recognition of a 'third dimension' that makes the interpreting educator relate to what he is looking for. Together with Merleau-Ponty, there is a 'return' to the ontological level, in which there is an understanding of the fact that people are each other's 'inheritors'. Going back further is impossible. By returning to the reflecting level, concepts like 'adaptation' and 'integration' get a different meaning. Discriminatory thinking will find no soil in this, which provides space for 'intermondial', 'intercultural' encounter possibilities. 3. Finally, in the third part, 'interculturality explained intermondially', the insights gained in the first section are connected to those treated in the second section. This implies that with the help of the described interworld concept, we try to come to a better understanding of a child's innerlife world by using children's stories. We will first see how Merleau-Ponty's phenomenological considerations, which are not directly appropriate for text-analytic interpretation, can be concentrated by means of Gadamer's hermeneutic interpretations. Then, the main characteristics of the 'intermonde' are being considered. These characteristics, circularity and stratification, are being exemplified by means of some children's expressions of lived experiences and specified with concepts like: 'hinge' (the opening of a door towards understanding of the other, exemplified by means of the concepts 'trust', 'family' and 'school'); and 'chiasmus' (the 'crossing' of cultures, explained by means of the concepts 'language' and 'adaptation'. These characteristics of intermondiality are being applied in the dynamic practice of project based initiatives related to the intercultural education of teachers-to-be. By interpreting some personal descriptions of lived experiences, a picture is drawn of the difficulties involved in the stimulation of education on the basis of intercultural meetings at initiating colleges. It has been shown that the best chances for intercultural encounters to succeed can be obtained when teachers and students are willing to stimulate each other in a co-operative mutual working relation, knowing that all parties' singularity is being respected. Then, intensive co-operation on a basis of trust between autochthonous people and people from foreign descent is unbearable. Following these case descriptions, an attempt is being made to create a more solid foundation for intercultural encounters and education: when can one really speak of intercultural communication? The insight that 'intermondiality' leads to 'interculturality' shows that in the education and child raising practice, the long searched for 'intercultural education' is still not functioning. Moreover, a theoretical basis is missed. Solutions are most often searched for in the practical sphere of 'getting to know other cultures' while, in reality these solutions are often no more than bogus solutions because of their temporary character. In order to introduce the intercultural principle in the entire educational system in a responsible manner, another, more flexible, intermondial attitude needs to be stimulated amongst teachers. The variability of social obviousness brings along the need for them to change. If teachers manage to do so, they will be able to judge the cognitive approach of interculturality critically. The basic assumption is that knowledge of other cultures leads naturally to more respect and to the 'other one' representing these cultures looking upon us as an 'other allochthonous one'. They will therefore search for a more sensitive, lived experience-focused approach, following the opposite direction, which makes clear that a change of manner and mentality is a condition for a better understanding of differences between cultures. In such a vision, the intercultural methods of projects are not being denied but only appreciated as secondary, complementing methods. Finally, the extent to which 'trans-culturality' can be a significant alternative is being considered. It is?being noticed that a 'trans-cultural approach of interculturality' cannot solve these issues, as long as only cognitive instead of intermondial, lived experience coloured, dimensions are being attributed to interculturality

Continuation of connecting orbits in 3D-ODEs: (I) Point-to-cycle connections

We propose new methods for the numerical continuation of point-to-cycle connecting orbits in 3-dimensional autonomous ODE's using projection boundary conditions. In our approach, the projection boundary conditions near the cycle are formulated using an eigenfunction of the associated adjoint variational equation, avoiding costly and numerically unstable computations of the monodromy matrix. The equations for the eigenfunction are included in the defining boundary-value problem, allowing a straightforward implementation in AUTO, in which only the standard features of the software are employed. Homotopy methods to find connecting orbits are discussed in general and illustrated with several examples, including the Lorenz equations. Complete AUTO demos, which can be easily adapted to any autonomous 3-dimensional ODE system, are freely available.Comment: 18 pages, 10 figure

Single-bubble and multi-bubble cavitation in water triggered by laser-driven focusing shock waves

In this study a single laser pulse spatially shaped into a ring is focused into a thin water layer, creating an annular cavitation bubble and cylindrical shock waves: an outer shock that diverges away from the excitation laser ring and an inner shock that focuses towards the center. A few nanoseconds after the converging shock reaches the focus and diverges away from the center, a single bubble nucleates at the center. The inner diverging shock then reaches the surface of the annular laser-induced bubble and reflects at the boundary, initiating nucleation of a tertiary bubble cloud. In the present experiments, we have performed time-resolved imaging of shock propagation and bubble wall motion. Our experimental observations of single-bubble cavitation and collapse and appearance of ring-shaped bubble clouds are consistent with our numerical simulations that solve a one dimensional Euler equation in cylindrical coordinates. The numerical results agree qualitatively with the experimental observations of the appearance and growth of bubble clouds at the smallest laser excitation rings. Our technique of shock-driven bubble cavitation opens novel perspectives for the investigation of shock-induced single-bubble or multi-bubble cavitation phenomena in thin liquids