Strongly Universal Reversible Gate Sets

It is well-known that the Toffoli gate and the negation gate together yield a universal gate set, in the sense that every permutation of $\{0,1\}^n$ can be implemented as a composition of these gates. Since every bit operation that does not use all of the bits performs an even permutation, we need to use at least one auxiliary bit to perform every permutation, and it is known that one bit is indeed enough. Without auxiliary bits, all even permutations can be implemented. We generalize these results to non-binary logic: If $A$ is a finite set of odd cardinality then a finite gate set can generate all permutations of $A^n$ for all $n$, without any auxiliary symbols. If the cardinality of $A$ is even then, by the same argument as above, only even permutations of $A^n$ can be implemented for large $n$, and we show that indeed all even permutations can be obtained from a finite universal gate set. We also consider the conservative case, that is, those permutations of $A^n$ that preserve the weight of the input word. The weight is the vector that records how many times each symbol occurs in the word. It turns out that no finite conservative gate set can, for all $n$, implement all conservative even permutations of $A^n$ without auxiliary bits. But we provide a finite gate set that can implement all those conservative permutations that are even within each weight class of $A^n$.Comment: Submitted to Rev Comp 201

Un indice biologique lacustre basé sur l'examen des oligochètes

L'utilisation des indices oligochètes relevés dans la littérature pose un certain nombre de problèmes conceptuels et pratiques lorsque l'on étudie des lacs de taille réduite, le rôle des sédiments dans la distribution des oligochètes étant la plupart du temps ignoré.A partir d'analyses en composantes principales normées (ACP) comprenant, comme variables actives, 12 variables physico-chimiques des sédiments profonds de 12 lacs situés dans le Jura et les Vosges, nous avons projeté, en données supplémentaires, la physico-chimie des eaux et des variables biologiques (nombre d'espèces et effectifs d'oligochètes).Les analyses mettent en évidence un premier facteur F1, commun aux sédiments de tous les lacs étudiés et caractérisé par un antagonisme entre la matière organique (C, N, P) et les carbonates. Ce facteur est considéré ici comme exprimant une capacité métabolique des plans d'eau à minéraliser la matière organique. Les variables physico-chimiques des eaux se projettent sur cette structure et ne contredisent pas la signification accordée au facteur F1. Les variables biologiques ne se révèlent fortement corrélées qu'avec F1, et s'opposent aux variables décrivant les teneurs en matières organiques.Par une régression multiple où la variable à expliquer est constituée par la première coordonnée factorielle des stations d'échantillonnage, on obtient l'indice EOLA = nombre d'espèces d'oligochètes + 3.log10 des effectifs d'oligochètes/0,1 m2, qui est corrélé avec la structure physico-chimique mise en évidence dans les ACP. Cet indice est considéré comme une potentialité biologique liée à la capacité des lacs à minéraliser la matière organique, capacité qui peut se révéler faible en raison de la présence d'apports d'origine autochtone ou allochtone (en particulier les rejets humains).Oligochaetes are often considered as good descriptors of the ecological situation in lakes. Unfortunately, the rote of sediments in the distribution of species is not well known, particularly in mail lakes. This problem needed re-examination, the importance of the sediments being emphasized. Twelve physico-chemical variables of the sediments (table 2) were taken into account and analysed by means of a standardized principal component analysis (PCA). The physico-chemical variables of the waters as well as the biological variables (species richness and abundance of oligochaetes, table 2) were projected as supplementary data in the PCA.The first principal component is characterized by an opposition between the organic matter (C, N, P) and the CaCO3 contents of the sediments (table 3). The second factor represents the total phosphorus. Lakes from cristalline area (Longemer and Gérardmer) are very contributive to the factor 2 as the total phosphorus contents of their sediments are very high (fig. 1 and table 6). When these lakes are removed from the data set, the second PCA indicates no changes in the signification of factor 1 (table 4). In both analyses, physicochemical variables of waters are correlated with the first factor, and do not contradict its signification. Biological variables are only correlated with factor 1 and show an opposite direction to organic matter (fig. 2).It is suggested that the first factor represents the capacities of the lakes to mineralize the organic matter. The first co-ordinates of sampling stations (COF1), the mean number of oligochaete species (NSPS) and the mean log10 of their abundance/0.1 m2 (EFFE) were compared by means of a multiple regression (table 5). The following biological index is obtained : EOLA = NSPS + 3EFFE. This oligochaete index is related to the factor 1 and it is suggested that if gives an assessment of the biological potentialities of lakes, these potentialities being related to the mineralizing capacities. Low values of the index EOLA are obtained both from human and natural organic enrichment

An Explicit Framework for Interaction Nets

Interaction nets are a graphical formalism inspired by Linear Logic proof-nets often used for studying higher order rewriting e.g. \Beta-reduction. Traditional presentations of interaction nets are based on graph theory and rely on elementary properties of graph theory. We give here a more explicit presentation based on notions borrowed from Girard's Geometry of Interaction: interaction nets are presented as partial permutations and a composition of nets, the gluing, is derived from the execution formula. We then define contexts and reduction as the context closure of rules. We prove strong confluence of the reduction within our framework and show how interaction nets can be viewed as the quotient of some generalized proof-nets

Annexin XIIIb: a novel epithelial specific annexin is implicated in vesicular traffic to the apical plasma membrane

The sorting of apical and basolateral proteins into vesicular carriers takes place in the trans-Golgi network (TGN) in MDCK cells. We have previously analyzed the protein composition of immunoisolated apical and basolateral transport vesicles and have now identified a component that is highly enriched in apical vesicles. Isolation of the encoding cDNA revealed that this protein, annexin XIIIb, is a new isoform of the epithelial specific annexin XIII sub-family which includes the previously described intestine-specific annexin (annexin XIIIa; Wice, B. M., and J. I, Gordon. 1992. J. Cell Biol. 116:405-422). Annexin XIIIb differs from annexin XIIIa in that it contains a unique insert of 41 amino acids in the NH2 terminus and is exclusively expressed in dog intestine and kidney, Immunofluorescence microscopy demonstrated that annexin XIIIb was localized to the apical plasma membrane and underlying punctate structures. Since annexins have been suggested to play a role in membrane-membrane interactions in exocytosis and endocytosis, we investigated whether annexin XIIIb, is involved in delivery to the apical cell surface. To this aim we used permeabilized MDCK cells and a cytosol-dependent in vitro transport assay. Antibodies specific for annexin XIIIb significantly inhibited the transport of influenza virus hemagglutinin from the TGN to the apical plasma membrane while the transport of vesicular stomatitis virus glycoprotein to the basolateral cell surface was unaffected. We propose that annexin XIIIb, plays a role in vesicular transport to the apical plasma membrane in MDCK cells

Quantitative Models and Implicit Complexity

We give new proofs of soundness (all representable functions on base types lies in certain complexity classes) for Elementary Affine Logic, LFPL (a language for polytime computation close to realistic functional programming introduced by one of us), Light Affine Logic and Soft Affine Logic. The proofs are based on a common semantical framework which is merely instantiated in four different ways. The framework consists of an innovative modification of realizability which allows us to use resource-bounded computations as realisers as opposed to including all Turing computable functions as is usually the case in realizability constructions. For example, all realisers in the model for LFPL are polynomially bounded computations whence soundness holds by construction of the model. The work then lies in being able to interpret all the required constructs in the model. While being the first entirely semantical proof of polytime soundness for light logi cs, our proof also provides a notable simplification of the original already semantical proof of polytime soundness for LFPL. A new result made possible by the semantic framework is the addition of polymorphism and a modality to LFPL thus allowing for an internal definition of inductive datatypes.Comment: 29 page

Influence of mining excavation on energy redistribution and rockburst potential

International audienceWith the increase of mining depth, rockburst is one of the most serious disasters which threaten the safety of mine operators and the surface stability. Several approaches have been developed since the sixties to assess rockburst potential in underground hardrock mines. Some of the approaches are based on energy balance around mining excavations such as the Energy Release Rate (ERR) that was developed in South Africa and more recently the strain Energy Storage Rate (ESR). This paper presents the results of a detailed numerical modeling case study for the assessment of rockburst potential in a room-and-pillar copper mine in Poland. The method of numerical simulation is a quasi-static finite difference method (FDM - FLAC3D). The Energy Storage Rate (ESR) is numerically calculated to predict burst occurrence

Metric trees of generalized roundness one

Every finite metric tree has generalized roundness strictly greater than one. On the other hand, some countable metric trees have generalized roundness precisely one. The purpose of this paper is to identify some large classes of countable metric trees that have generalized roundness precisely one. At the outset we consider spherically symmetric trees endowed with the usual combinatorial metric (SSTs). Using a simple geometric argument we show how to determine decent upper bounds on the generalized roundness of finite SSTs that depend only on the downward degree sequence of the tree in question. By considering limits it follows that if the downward degree sequence $(d_{0}, d_{1}, d_{2}...)$ of a SST $(T,\rho)$ satisfies $|\{j \, | \, d_{j} > 1 \}| = \aleph_{0}$, then $(T,\rho)$ has generalized roundness one. Included among the trees that satisfy this condition are all complete $n$-ary trees of depth $\infty$ ($n \geq 2$), all $k$-regular trees ($k \geq 3$) and inductive limits of Cantor trees. The remainder of the paper deals with two classes of countable metric trees of generalized roundness one whose members are not, in general, spherically symmetric. The first such class of trees are merely required to spread out at a sufficient rate (with a restriction on the number of leaves) and the second such class of trees resemble infinite combs.Comment: 14 pages, 2 figures, 2 table

Identification and stable expression of vitellogenin receptor (VTGR) through vitellogenesis in the European eel

[EN] In teleosts, vitellogenin (Vtg) is a phospholipoglycoprotein synthesized by the liver, released into the blood circulation and incorporated into the oocytes via endocytosis mediated by the Vtg receptor (VTGR) to form the yolk granules. The VTGR is crucial for oocyte growth in egg-laying animals but is also present in non-oviparous vertebrates, such as human. The VTGR belongs to the low-density lipoprotein receptor superfamily (LDLR) and is also named very-low-density lipoprotein receptor (VLDLR). In this study, we identified and phylogenetically positioned the VTGR of a basal teleost, the European eel, Anguilla anguilla. We developed quantitative real-time PCR (qRT-PCR) and investigated the tissue distribution of vtgr transcripts. We compared by qRT-PCR the ovarian expression levels of vtgr in juvenile yellow eels and pre-pubertal silver eels. We also analyzed the regulation of ovarian vtgr expression throughout vitellogenesis in experimentally matured eels. The Vtg plasma level was measured by homologous ELISA experimental maturation. Our in silico search and phylogenetical analysis revealed a single vtgr in the European eel, orthologous to other vertebrate vtgr. The qRT-PCR studies revealed that vtgr is mainly expressed in the ovary and also detected in various other tissues such as brain, pituitary, gill, fat, heart, and testis, suggesting some extra-ovarian functions of VTGR. We showed that vtgr is expressed in ovaries of juvenile yellow eels with no higher expression in pre-pubertal silver eels nor in experimentally matured eels. This suggests that vtgr transcription already occurs during early pre-vitellogenesis of immature eels and is not further activated in vitellogenic oocytes. European eel Vtg plasma level increased throughout experimental maturation in agreement with previous studies. Taken together, these results suggest that vtgr transcript levels may not be a limiting step for the uptake of Vtg by the oocyte in the European eel.M.M., A.G.L. and S.D. were granted with Short Term Scientific Missions by the COST Office (COST Action FA1205: AQUAGAMETE). S.D. was also awarded with a grant from the UPV's School of Doctorate (Accion para la Internacionalizacion de los Programas de Doctorado) in 2017. We thank E. Feunteun and colleagues, MNHN, Dinard, for the ovarian samples from eels of the Fremur, France.Morini, M.; Lafont, AG.; Maugars, G.; Baloche, S.; Dufour, S.; Asturiano, JF.; Pérez Igualada, LM. (2020). Identification and stable expression of vitellogenin receptor (VTGR) through vitellogenesis in the European eel. Animal. 14(6):1213-1222. https://doi.org/10.1017/S1751731119003355S12131222146Abascal, F., Zardoya, R., & Posada, D. (2005). ProtTest: selection of best-fit models of protein evolution. Bioinformatics, 21(9), 2104-2105. doi:10.1093/bioinformatics/bti263Ali, B. R., Silhavy, J. L., Gleeson, M. J., Gleeson, J. G., & Al-Gazali, L. (2012). A missense founder mutation in VLDLR is associated with Dysequilibrium Syndrome without quadrupedal locomotion. BMC Medical Genetics, 13(1). doi:10.1186/1471-2350-13-80Andersen, Ø., Xu, C., Timmerhaus, G., Kirste, K. H., Naeve, I., Mommens, M., & Tveiten, H. (2017). Resolving the complexity of vitellogenins and their receptors in the tetraploid Atlantic salmon (Salmo salar ): Ancient origin of the phosvitin-less VtgC in chondrichthyean fishes. Molecular Reproduction and Development, 84(11), 1191-1202. doi:10.1002/mrd.22881Bidwell, C., & Carlson, D. (1995). Characterization of vitellogenin from white sturgeon, Acipenser transmontanus. Journal of Molecular Evolution, 41(1). doi:10.1007/bf00174046Bujo, H., Hermann, M., Kaderli, M. O., Jacobsen, L., Sugawara, S., Nimpf, J., … Schneider, W. J. (1994). Chicken oocyte growth is mediated by an eight ligand binding repeat member of the LDL receptor family. The EMBO Journal, 13(21), 5165-5175. doi:10.1002/j.1460-2075.1994.tb06847.xBurzawa-Gerard, E., & Dumas-Vidal, A. (1991). Effects of 17β-estradiol and carp gonadotropin on vitellogenesis in normal and hypophysectomized European silver female eel (Anguilla anguilla L.) employing a homologous radioimmunoassay for vitellogenin. General and Comparative Endocrinology, 84(2), 264-276. doi:10.1016/0016-6480(91)90049-cChen, J.-N., López, J. A., Lavoué, S., Miya, M., & Chen, W.-J. (2014). Phylogeny of the Elopomorpha (Teleostei): Evidence from six nuclear and mitochondrial markers. Molecular Phylogenetics and Evolution, 70, 152-161. doi:10.1016/j.ympev.2013.09.002Clelland, E. S., & Kelly, S. P. (2010). Tight junction proteins in zebrafish ovarian follicles: Stage specific mRNA abundance and response to 17β-estradiol, human chorionic gonadotropin, and maturation inducing hormone. General and Comparative Endocrinology, 168(3), 388-400. doi:10.1016/j.ygcen.2010.05.011Damsteegt, E. L., Mizuta, H., Hiramatsu, N., & Lokman, P. M. (2015). How do eggs get fat? Insights into ovarian fatty acid accumulation in the shortfinned eel, Anguilla australis. General and Comparative Endocrinology, 221, 94-100. doi:10.1016/j.ygcen.2014.12.019Dufour S, Burzawa-Gerard E, Le Belle N, Sbaihi M and Vidal B 2003. Reproductive endocrinology of the European eel, Anguilla anguilla. In Eel biology (eds. K Aida, K Tsukamoto and K Yamauchi ), pp 373–383. Springer-Verlag, Tokyo, Japan.Dufour, S., Lopez, E., Le Menn, F., Le Belle, N., Baloche, S., & Fontaine, Y. A. (1988). Stimulation of gonadotropin release and of ovarian development, by the administration of a gonadoliberin agonist and of dopamine antagonists, in female silver eel pretreated with estradiol. General and Comparative Endocrinology, 70(1), 20-30. doi:10.1016/0016-6480(88)90090-1Henkel, C. V., Burgerhout, E., de Wijze, D. L., Dirks, R. P., Minegishi, Y., Jansen, H. J., … van den Thillart, G. E. E. J. M. (2012). Primitive Duplicate Hox Clusters in the European Eel’s Genome. PLoS ONE, 7(2), e32231. doi:10.1371/journal.pone.0032231Henkel, C. V., Dirks, R. P., de Wijze, D. L., Minegishi, Y., Aoyama, J., Jansen, H. J., … van den Thillart, G. E. E. J. M. (2012). First draft genome sequence of the Japanese eel, Anguilla japonica. Gene, 511(2), 195-201. doi:10.1016/j.gene.2012.09.064Herz, J., & Bock, H. H. (2002). Lipoprotein Receptors in the Nervous System. Annual Review of Biochemistry, 71(1), 405-434. doi:10.1146/annurev.biochem.71.110601.135342Hiramatsu, N., Luo, W., Reading, B. J., Sullivan, C. V., Mizuta, H., Ryu, Y.-W., … Hara, A. (2012). Multiple ovarian lipoprotein receptors in teleosts. Fish Physiology and Biochemistry, 39(1), 29-32. doi:10.1007/s10695-012-9612-6Hiramatsu, N., Todo, T., Sullivan, C. V., Schilling, J., Reading, B. J., Matsubara, T., … Hara, A. (2015). Ovarian yolk formation in fishes: Molecular mechanisms underlying formation of lipid droplets and vitellogenin-derived yolk proteins. General and Comparative Endocrinology, 221, 9-15. doi:10.1016/j.ygcen.2015.01.025Hummel, S., Lynn, E. G., Osanger, A., Hirayama, S., Nimpf, J., & Schneider, W. J. (2003). Molecular characterization of the first avian LDL receptor. Journal of Lipid Research, 44(9), 1633-1642. doi:10.1194/jlr.m300014-jlr200Jéhannet P, Kruijt L, Damsteegt EL, Swinkels W, Heinsbroek LTN, Lokman PM and Palstra AP. A mechanistic model for studying the initiation of anguillid vitellogenesis by comparing the European eel (Anguilla anguilla) and the shortfinned eel (A. australis). General and Comparative Endocrinology (in press). https://doi.org/10.1016/j.ygcen.2019.02.018Lafont, A.-G., Rousseau, K., Tomkiewicz, J., & Dufour, S. (2016). Three nuclear and two membrane estrogen receptors in basal teleosts, Anguilla sp.: Identification, evolutionary history and differential expression regulation. General and Comparative Endocrinology, 235, 177-191. doi:10.1016/j.ygcen.2015.11.021Mazzeo, I., Peñaranda, D. S., Gallego, V., Baloche, S., Nourizadeh-Lillabadi, R., Tveiten, H., … Pérez, L. (2014). Temperature modulates the progression of vitellogenesis in the European eel. Aquaculture, 434, 38-47. doi:10.1016/j.aquaculture.2014.07.020Mizuta, H., Luo, W., Ito, Y., Mushirobira, Y., Todo, T., Hara, A., … Hiramatsu, N. (2013). Ovarian expression and localization of a vitellogenin receptor with eight ligand binding repeats in the cutthroat trout (Oncorhynchus clarki). Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology, 166(1), 81-90. doi:10.1016/j.cbpb.2013.07.005Mizuta, H., Mushirobira, Y., Nagata, J., Todo, T., Hara, A., Reading, B. J., … Hiramatsu, N. (2017). Ovarian expression and localization of clathrin (Cltc) components in cutthroat trout, Oncorhynchus clarki: Evidence for Cltc involvement in endocytosis of vitellogenin during oocyte growth. Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 212, 24-34. doi:10.1016/j.cbpa.2017.06.021Morini, M., Peñaranda, D. S., Vílchez, M. C., Gallego, V., Nourizadeh-Lillabadi, R., Asturiano, J. F., … Pérez, L. (2015). Transcript levels of the soluble sperm factor protein phospholipase C zeta 1 (PLCζ1) increase through induced spermatogenesis in European eel. Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 187, 168-176. doi:10.1016/j.cbpa.2015.05.028Morini, M., Peñaranda, D. S., Vílchez, M. C., Nourizadeh-Lillabadi, R., Lafont, A.-G., Dufour, S., … Pérez, L. (2017). Nuclear and membrane progestin receptors in the European eel: Characterization and expression in vivo through spermatogenesis. Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 207, 79-92. doi:10.1016/j.cbpa.2017.02.009Nader, N., Dib, M., Courjaret, R., Hodeify, R., Machaca, R., Graumann, J., & Machaca, K. (2018). VLDL receptor regulates membrane progesterone receptor trafficking and non-genomic signaling. Journal of Cell Science. doi:10.1242/jcs.212522Okabayashi, K., Shoji, H., Nakamura, T., Hashimoto, O., Asashima, M., & Sugino, H. (1996). cDNA Cloning and Expression of theXenopus laevisVitellogenin Receptor. Biochemical and Biophysical Research Communications, 224(2), 406-413. doi:10.1006/bbrc.1996.1040Palstra, A. P., & van den Thillart, G. E. E. J. M. (2010). Swimming physiology of European silver eels (Anguilla anguilla L.): energetic costs and effects on sexual maturation and reproduction. Fish Physiology and Biochemistry, 36(3), 297-322. doi:10.1007/s10695-010-9397-4Pankhurst, N. W. (1982). Relation of visual changes to the onset of sexual maturation in the European eel Anguilla anguilla (L.). Journal of Fish Biology, 21(2), 127-140. doi:10.1111/j.1095-8649.1982.tb03994.xPasquier, J., Lafont, A.-G., Jeng, S.-R., Morini, M., Dirks, R., van den Thillart, G., … Dufour, S. (2012). Multiple Kisspeptin Receptors in Early Osteichthyans Provide New Insights into the Evolution of This Receptor Family. PLoS ONE, 7(11), e48931. doi:10.1371/journal.pone.0048931Perez, L., Aturiano, J. F., Tomas, A., Zegrari, S., Barrera, R., Espinos, F. J., … Jover, M. (2000). Induction of maturation and spermiation in the male European eel: assessment of sperm quality throughout treatment. Journal of Fish Biology, 57(6), 1488-1504. doi:10.1111/j.1095-8649.2000.tb02227.xPérez L, Vílchez MC, Gallego V, Mazzeo I, Peñaranda DS, Weltzien FA, Dufour S and Asturiano JF 2012. Trying to reproduce the European eel (Anguilla anguilla) under captivity: experiments with females. In Proceeding of the Domestication in Finfish Aquaculture, October 2012, Olsztyn, Poland, pp. 11–15.Prat, F., Coward, K., Sumpter, J. P., & Tyler, C. R. (1998). Molecular Characterization and Expression of two Ovarian Lipoprotein Receptors in the Rainbow Trout, Oncorhynchus mykiss 1. Biology of Reproduction, 58(5), 1146-1153. doi:10.1095/biolreprod58.5.1146Reading, B. J., Hiramatsu, N., Schilling, J., Molloy, K. T., Glassbrook, N., Mizuta, H., … Sullivan, C. V. (2014). Lrp13 is a novel vertebrate lipoprotein receptor that binds vitellogenins in teleost fishes. Journal of Lipid Research, 55(11), 2287-2295. doi:10.1194/jlr.m050286Stamatakis, A. (2014). RAxML version 8: a tool for phylogenetic analysis and post-analysis of large phylogenies. Bioinformatics, 30(9), 1312-1313. doi:10.1093/bioinformatics/btu033Takahashi, S., Kawarabayasi, Y., Nakai, T., Sakai, J., & Yamamoto, T. (1992). Rabbit very low density lipoprotein receptor: a low density lipoprotein receptor-like protein with distinct ligand specificity. Proceedings of the National Academy of Sciences, 89(19), 9252-9256. doi:10.1073/pnas.89.19.9252Thompson, J. D., Higgins, D. G., & Gibson, T. J. (1994). CLUSTAL W: improving the sensitivity of progressive multiple sequence alignment through sequence weighting, position-specific gap penalties and weight matrix choice. Nucleic Acids Research, 22(22), 4673-4680. doi:10.1093/nar/22.22.4673Trommsdorff, M., Gotthardt, M., Hiesberger, T., Shelton, J., Stockinger, W., Nimpf, J., … Herz, J. (1999). Reeler/Disabled-like Disruption of Neuronal Migration in Knockout Mice Lacking the VLDL Receptor and ApoE Receptor 2. Cell, 97(6), 689-701. doi:10.1016/s0092-8674(00)80782-5Tyler, C. R., Pottinger, T. G., Coward, K., Prat, F., Beresford, N., & Maddix, S. (1997). Salmonid Follicle-Stimulating Hormone (GtH I) Mediates Vitellogenic Development of Oocytes in the Rainbow Trout, Oncorhynchus mykiss 1. Biology of Reproduction, 57(5), 1238-1244. doi:10.1095/biolreprod57.5.1238Weltzien, F.-A., Pasqualini, C., Vernier, P., & Dufour, S. (2005). A quantitative real-time RT-PCR assay for European eel tyrosine hydroxylase. General and Comparative Endocrinology, 142(1-2), 134-142. doi:10.1016/j.ygcen.2004.12.01

Study of the microstructure resulting from brazed aluminium materials used in heat exchangers

Re-solidification of AA4343 cladding after brazing as well as the related precipitation in the modified AA3003 core material have been investigated. Analysis of the re-solidified material showed that partial dissolution of the core alloy occurs in both the brazing joints and away of them. Far from the brazing joints, the dissolution is, however, limited and diffusion of silicon from the liquid into the core material leads to solid-state precipitation in the so-called “band of dense precipitates” (BDP). On the contrary, the dissolution is enhanced in the brazing joint to such an extent that no BDP could be observed. The intermetallic phases present in the resolidified areas as well as in the core material have been analyzed and found to be mainly cubic alpha-Al(Mn,Fe)Si. These results were then compared to predictions made with available phase diagram information

Graph Creation, Visualisation and Transformation

We describe a tool to create, edit, visualise and compute with interaction nets - a form of graph rewriting systems. The editor, called GraphPaper, allows users to create and edit graphs and their transformation rules using an intuitive user interface. The editor uses the functionalities of the TULIP system, which gives us access to a wealth of visualisation algorithms. Interaction nets are not only a formalism for the specification of graphs, but also a rewrite-based computation model. We discuss graph rewriting strategies and a language to express them in order to perform strategic interaction net rewriting