Unusual manganese enrichment in the Mesoarchean Mozaan Group, Pongola Supergroup, South Africa

An unusual sediment-hosted manganese deposit is described from the Mesoarchean Mozaan Group, Pongola Supergroup, South Africa. MnO contents up to 15 wt.% were observed in marine clastic and chemical sedimentary rocks. Mn enrichment is interpreted to have resulted from the hydrothermal alteration of manganiferous shale and BIF parent rocks, the primary MnO contents of which are as high as 8.5 wt.%. A detailed mineralogical and petrographic study shows that these parent rocks are characterized by manganoan siderite, ferroan rhodochrosite and other Mn-Fe-rich mineral phases, such as kutnohorite and Fe-Mn-chlorite. Their hypogene alteration gave rise to a diversification of mineral assemblages where ferroan tephroite, calcian rhodochrosite, rhodochrosite, pyrochroite, pyrophanite, cronstedtite, manganoan Fe-rich chlorite and manganoan phlogopite partially or totally replaced the previous mineral assemblage. Thermodynamic modeling performed on chlorite phases associated with the described mineral assemblages illustrates a decrease of average crystallization temperatures from ca. 310 °C during early metamorphic stages to ca. 250 °C during a hydrothermal stage. Mineral transformation processes were thus related to retrograde metamorphism and/or hydrothermal alteration post-dating metamorphism and gave rise to progressive Mn enrichment from unaltered parent to altered rocks. The timing of hypogene alteration was constrained by 40Ar/39Ar dating to between about 1500 and 1100 Ma ago, reflecting tectonic processes associated with the Namaqua-Natal orogeny along the southern Kaapvaal Craton margin. Manganiferous shale and BIF of the Mozaan Group may represent the oldest known examples of primary sedimentary Mn deposition, related to oxidation of dissolved Mn(II) by free oxygen in a shallow marine environment. Oxygenic photosynthesis would have acted as a first-order control during Mn precipitation. This hypothesis opens a new perspective for better constraining secular evolution of sediment-hosted mineral deposits linked to oxygen levels in the atmosphere-hydrosphere system during the Archean Eon

ArgoNeuT, a liquid argon time projection chamber in a low energy neutrino beam

ArgoNeuT (Argon Neutrino Test), a NSF/DOE project at Fermilab, is the first LArTPC to go in a low energy neutrino beam and just the second LArTPC to go in a neutrino beam ever. ArgoNeuT sits just upstream of the on-axis MINOS near detector in the NuMI beamline, about 1 km from the target station and 100 m underground. The detector features a 47X40X90 cm (169 L) active volume TPC with a fully contained recirculation and purification system. Among other physics, ArgoNeuT will measure the charged-current quasi-elastic (anti-) neutrino cross section on argon at an energy of ~3 GeV.Comment: 3 pages, 2 figures, to appear in the proceedings of the 11th International Conference on Topics in Astroparticle and Underground Physics (TAUP 2009), Rome, Italy, 1-5 July 200

Flavour and polarisation in heavy neutrino production at e+ e- colliders

We analyse l W nu production at ILC, paying special attention to the role of the final lepton flavour and beam polarisation in the search for a new heavy neutrino N. We show that a sizeable coupling to the electron V_eN ~ 10^-2 is necessary to have an observable signal in any of the channels, despite the fact that the signal may be more visible in muon or tau final states. The non-observation of a heavy neutrino at ILC will improve the present upper bound on its mixing with the electron by more than one order of magnitude, V_eN < 0.007 for m_N between 200 and 400 GeV.Comment: 17 pages, 5 PS figures. References added. To be published in PL

Netlang: A software for the linguistic analysis of corpora by means of complex networks

To date there is no software that directly connects the linguistic analysis of a conversation to a network program. Networks programs are able to extract statistical information from data basis with information about systems of interacting elements. Language has also been conceived and studied as a complex system. However, most proposals do not analyze language according to linguistic theory, but use instead computational systems that should save time at the price of leaving aside many crucial aspects for linguistic theory. Some approaches to network studies on language do apply precise linguistic analyses, made by a linguist. The problem until now has been the lack of interface between the analysis of a sentence and its integration into the network that could be managed by a linguist and that could save the analysis of any language. Previous works have used old software that was not created for these purposes and that often produced problems with some idiosyncrasies of the target language. The desired interface should be able to deal with the syntactic peculiarities of a particular language, the options of linguistic theory preferred by the user and the preservation of morpho-syntactic information (lexical categories and syntactic relations between items). Netlang is the first program able to do that. Recently, a new kind of linguistic analysis has been developed, which is able to extract a complexity pattern from the speaker’s linguistic production which is depicted as a network where words are inside nodes, and these nodes connect each other by means of edges or links (the information inside the edge can be syntactic, semantic, etc.). The Netlang software has become the bridge between rough linguistic data and the network program. Netlang has integrated and improved the functions of programs used in the past, namely the DGA annotator and two scripts (ToXML.pl and Xml2Pairs.py) used for transforming and pruning data. Netlang allows the researcher to make accurate linguistic analysis by means of syntactic dependency relations between words, while tracking record of the nature of such syntactic relationships (subject, object, etc). The Netlang software is presented as a new tool that solve many problems detected in the past. The most important improvement is that Netlang integrates three past applications into one program, and is able to produce a series of file formats that can be read by a network program. Through the Netlang software, the linguistic network analysis based on syntactic analyses, characterized for its low cost and the completely non-invasive procedure aims to evolve into a sufficiently fine grained tool for clinical diagnosis in potential cases of language disorders

Efecto de las adiciones puzolánicas en la retracción de pastas y morteros de cemento en sus primeras edades

The traditional favour enjoyed by cement including additions and by their diverse uses in Chile calls for an extense investigation of their behaviour in order that the results may justify their utilization in specific projects. This works studies volume changes occurring in cement pastes and mortars containing pozzolan additions during their first hours of age. This investigation used cements made in the laboratory from raw materials supplied by chilean manufacturers. Two types of clinkers were used, namely; a gypsum type and a natural pozzolan type, added in proportions ranging from 0 to 30%.Tests were conducted to ascertain the shrinkage of cement pastes and mortars since the first moments following their mixing operation, employing there for moulds fitted with a special device designed and implemented at the laboratory of the IDIEM Department of Agglomerants. The results thus gathered corroborated the fact that independently of cement characteristics, in general the deformation of pastes and mortars exhibits successive periods of first shrinkage swelling, and second shrinkage. The first shrinkage is affected by the ambient conditions of humidity, temperature, and wind (evaporation), but also in a preponderant way by cement specific surface, which allows higher velocity in the chemical reactions occurring during that period. Moreover the compactation degree is also affecting shrinkage, here. On the other hand, it was confirmed that with cements of like fineness, those having higher C3A contents exhibit an overall shrinkage larger than that of cements having low contents. At last it was possible to ascertain that an increase in pozzolan contents does not affect shrinkage directly, but that its presence may eventually modify the gypsum/clinker ratio and thus give rise to changes, specially in the two States of swelling and second shrinkage.La tradicional aceptación en Chile de los cementos con adición y su diversidad de usos, requiere de una amplia investigación sobre su comportamiento para que los resultados avalen su utilización en proyectos determinados. En este trabajo se estudiaron los cambios volumétricos que se producen en las primeras horas de edad en pastas y morteros de cemento con adición puzolánica, comparándolos entre sí y relacionándolos con otras propiedades de dichos cementos. Para ello se utilizaron cementos fabricados a escala de laboratorio con materias primas provenientes de fábricas nacionales. Se emplearon dos tipos de clínker diferentes, un tipo de yeso y un tipo de puzolana natural, adicionada en proporciones entre 0 y 30%. Se realizaron ensayos para determinar la retracción en pastas y morteros de cemento desde los primeros instantes de su amasado, utilizando para ello moldes dotados con un dispositivo especial diseñado e implementado en el Laboratorio de la Sección Aglomerantes del IDIEM. Los resultados ratifican que, independientemente de las diferentes características de los cementos, la deformación en pastas y morteros presenta, en general, períodos de primera retracción, hinchamiento y segunda retracción. La primera retracción se ve afectada por las condiciones ambientales de humedad, temperatura y viento (evaporación), pero también influye en forma preponderante la superficie específica de los cementos que permite mayor velocidad en las reacciones químicas que ocurren en ese período. También incide aquí una menor o mayor compactación. Por otro lado, se corroboró que a igualdad de finura, los cementos con mayor contenido de C3A presentan una mayor retracción total que los de bajo contenido. Se pudo constatar, finalmente, que el aumento del contenido de puzolana no afecta directamente en el fenómeno de retracción, pero su presencia puede eventualmente modificar la razón yeso/clínker produciendo variaciones, especialmente en los estados de hinchamiento y segunda retracción

ArgoNeuT and the Neutrino-Argon Charged Current Quasi-Elastic Cross Section

ArgoNeuT, a Liquid Argon Time Projection Chamber in the NuMI beamline at Fermilab, has recently collected thousands of neutrino and anti-neutrino events between 0.1 and 10 GeV. The experiment will, among other things, measure the cross section of the neutrino and anti-neutrino Charged Current Quasi-Elastic interaction and analyze the vertex activity associated with such events. These topics are discussed along with ArgoNeuT's automated reconstruction software, currently capable of fully reconstructing the muon and finding the event vertex in neutrino interactions.Comment: 6 pages, 4 figures, presented at the International Nuclear Physics Conference, Vancouver, Canada, July 4-9, 2010, to be published in Journal of Physics: Conference Series (JPCS

Detekcija polimorfizama jednog nukleotida (SNP-a) u HER2, MUC1, ESR1 i BRCA1 gena povezanih s tumorom mliječne žlijezde kuja

Worldwide, canine mammary cancer (CMC) is the most frequent type of neoplasia in female dogs, and it is three times more frequent in dogs than in humans. In Colombia, CMC is the second most frequent type of cancer, after skin neoplasia. Genetics is one of the most important factors involved in any type of cancer, and the genetic basis of this disease is reflected through line breeding due to changes in allelic frequencies that are traceable using molecular markers. This study aimed to detect single nucleotide polymorphisms (SNPs) associated with CMC in blood samples collected from collected from healthy and CMC female dogs at Diego Villegas Toro Veterinary Hospital of Universidad de Caldas (Manizales, Colombia). We designed primers using Primer-BLAST and Primer3, and gene fragments from HER2, MUC1, ESR1, and BRCA1 were amplified to identify SNPs through genome mapping using the UCSC Genome Institute genome browser. We used the genome of Canis lupus familaris Boxer breed [GCF_000002285.3, (CanFam 3.1)] as a reference to compare the gene fragments and SNPs. We associated SNPs with the CMC and control groups by testing odds ratios (OR) through Fisher’s exact tests to determine an association or risk for CMC. We detected two SNPs for ESR1, three for MUC1, six for HER2, and one for BRCA1. MUC1 was the only gene to display an SNP in an exonic region that resulted in an amino acid substitution (Pro>Thr). No significant differences based on the OR were found, though the majority of SNPs, with the exception of four, were found in females with CMC. We report a novel molecular marker for HER2 that amplifies exons 25–26 and introns 24-25, and highlight the importance of conducting further studies on MUC1 and elucidating the role of introns and splicing in candidate genes associated with CMC.Diljem svijeta, tumor mliječne žlijezde kuja (CMC) najčešća je skupina neoplazija kuja te je tri puta učestalija u pasa nego u ljudi. U Kolumbiji, CMC je bio druga najčešća vrsta tumora, nakon neoplazija na koži. Nadalje, genetika je jedan od najvažnijih čimbenika uključenih u bilo koju vrstu tumora, a genetska baza ove bolesti održava se kroz linijski uzgoj uslijed promjena alelnih frekvencija, koje se mogu pratiti preko molekularnih markera. Ova studija imala je za cilj detektirati polimorfizme jednog nukleotida (SNP-e) povezane s CMC-om u uzorcima krvi prikupljenih od kuja s CMC-om i zdravih kuja u veterinarskoj bolnici Diego Villegas Toro Sveučilišta Caldas (Manizales, Kolumbija). Dizajnirali smo početnice uporabom Primer-BLAST i Primer3 te su fragmenti gena HER2, MUC1, ESR1 i BRCA1 pojačani za identifikaciju SNP-a preko mapiranja genoma uporabom preglednika genoma Instituta za genom Sveučilišta Santa Cruz u Kaliforniji (UCSC). Rabili smo genom Canis lupus familaris pasmine bokser [GCF_000002285.3, (CanFam 3.1)] kao referencu za usporedbu fragmenata gena i SNP-a. Povezali smo SNP-e s CMC-om i kontrolnim skupinama testiranjem omjera izgleda (OR) pomoću Fisherovih egzaktnih testova za određivanje povezanosti ili rizika od CMC-a. Detektirali smo dva SNP-a za ESR1, tri za MUC1, šest za HER2 i jedan za BRCA1. MUC1 je bio jedini gen koji je pokazao SNP u regiji egzona što je rezultiralo supstitucijom aminokiseline (Pro>Thr). Nismo pronašli značajne razlike na temelju OR-a, premda je većina SNP-a, izuzev četiri, pronađena u kuja s CMC-om. Prijavljujemo novi molekularni marker za HER2 koji pojačava egzone 25 - 26 i introne 24 - 25 te naglašavamo važnost provođenja dodatnih studija na MUC1, kao i pojašnjenja uloge introna i izrezivanja u gena kandidata poveznih s CMC-om

On D0-branes in Gepner models

We show why and when D0-branes at the Gepner point of Calabi-Yau manifolds given as Fermat hypersurfaces exist.Comment: 22 pages, substantial improvements in sections 2 and 3, references added, version to be publishe