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Search Results: 1 - 10 of 4739 matches for " Thierry;Valencia "
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U-Pb and 40Ar/39Ar geochronology of the coastal Sonora batholith: New insights on Laramide continental arc magmatism
Ramos-Velázquez, Ernesto;Calmus, Thierry;Valencia, Victor;Iriondo, Alexander;Valencia-Moreno, Martín;Bellon, Hervé;
Revista mexicana de ciencias geológicas , 2008,
Abstract: the coastal sonora batholith comprises a series of cretaceous granitoids that intruded a metasedimentary basement of possible mesozoic age. they are partially covered by tertiary volcanic flows and pyroclastic rocks. in order to elucidate the crystallization and cooling history of the granitoids, nine rock samples -were collected from bahía kino to punta tepopa. eight samples dated by u-pb zircon geochronology show that the coastal sonora batholith was emplaced during the late cretaceous, between 90.1 ± 1.1 and 69.4 ± 1.2 ma. the interval of 20 ma between the different stages of crystallization indicate that magmatism was relatively static within coastal sonora, although the magmatic arc recorded an eastward migration as a whole during cretaceous and paleogene. in addition, three of these samples were also dated by 40ar/39ar in biotite and k-feldspar separates. ages vary from 74 to 67 ma in biotite and from -68 to 42 ma in k-feldspar. we interpret these ages as the cooling progression of the batholith, associated with exhumation of the region before the basin and range extension. furthermore, these results show a local trend towards younger ages to the north of the batholith, and they are in good agreement with the model of a general eastward migration of the cretaceous-tertiary magmatic arc in northwestern mexico. in general, the available ages suggest that the arc moved slowly across baja california between 140 and 105 ma, and continued its eastward migration across the eastern portion of baja california and sonora between 105 and 60 ma. according to the isotopic ages, the coastal sonora batholith would be the westernmost part of the laramide magmatic event (90 - 40 ma). thus, on the basis of new and available geochronologic, petrographic, and geochemical data, we propose that the coastal sonora batholith and the eastern portion of the peninsular ranges batholith belong to a single magmatic arc, which was separated during the continental breakup and rifting of the
Arizpe sub-basin: A sedimentary and volcanic record of Basin and Range extension in north-central Sonora, Mexico
González-León, Carlos M.;Valencia, Víctor A.;López-Martínez, Margarita;Bellon, Hervé;Valencia-Moreno, Martín;Calmus, Thierry;
Revista mexicana de ciencias geológicas , 2010,
Abstract: the arizpe sub-basin located in the northern part of the río sonora basin is a basin and range half-graben that initiated during late oligocene time in north-central sonora. its ~2.1 km-thick, east-dipping volcanic and sedimentary fill assigned to the báucarit formation is divided, from base upwards, into the following informal members. the la cieneguita member composed ofinterbedded conglomerate, siltstone and gypsum beds which unconformably overlay older cenozoic volcanic rocks; the el toro muerto basalt composed of basaltflows, basalt breccia and subordinate conglomerate beds; the arzipe conglomerate composed of three fining-upwards conglomerate sequences that interdigitates with flows of the tierras prietas basalt in its lower part and the agua caliente basalt in its upper part; the bamori member is a coarsening-upward succession of siltstone, sandstone and conglomerate that unconformably overlies the arizpe conglomerate and it is unconformably overlain by the sedimentary el catalán breccia. basin accommodation started at ~25 ma when deposition of the la cieneguita member, followed by alkaline basaltic volcanism of the el toro muerto and contemporaneous rhyolitic volcanism, floored the area predating significant clastic deposition. the agua caliente basalt (~21 ma) in the upper part of the basin fill indicates the basin was rapidly subsiding. multiple phases of normal faulting affected the arizpe sub-basin. the main controlling structure may be the steep (80°), west-dipping, sub-parallel el fuste and granaditas normal faults that bound the arizpe sub-basin at its present-day eastern margin, or there may be afault orfaults that were subsequently buried beneath younger basin fill near the eastern margin of the basin. the basin was disorganized by an even younger nw-se phase of normal faulting represented by the southwest-dipping crisanto and tahuichopa faults. growth strata within basin fill suggests that syntectonic deposition was active during all phases of norm
Enriquecimiento supergénico y análisis de balance de masa en el yacimiento de pórfido cuprífero Milpillas, Distrito Cananea, Sonora, México
Noguez-Alcántara, Benito;Valencia-Moreno, Martín;Roldán-Quintana, Jaime;Calmus, Thierry;
Revista mexicana de ciencias geológicas , 2007,
Abstract: milpillas is a porphyry copper deposit with supergene enrichment located in the sonora-arizona-new mexico metallogenic province, which is characterized by low-grade (0.1-0.15% cu) hypogene copper mineralization associated with the emplacement of laramide plutons. the post-laramide extensional tectonics promoted a rapid exposure of the hypogene mineralized zones to the weathering environment. this favored the development of outstanding leached caps and formation of supergene enriched chalcocite blankets at the base of the oxidized zones. the supergene ore zone occurs at depth under a postmineral column and a leached cap, which jointly accumulate from 150 to 700 m of vertical extent. this zone was preserved due to subsidence and burial by gravels of the cuitaca norte semigraben, a regional basin structure typical of the basin and range province. the dominant supergene alteration is characterized by pervasive clays, which overprint an earlier intense hypogene alteration. the latter was initially of potassic-propylitic nature, followed by moderate to strong phyllic and argillic phases, overlapping the earlier alteration. these mineral assemblages constitute a poor or non-reactive gangue with supergene acid solutions, which facilitated the development of the thick, zoned leached cap and secondary copper concentration. the supergene mineralization is characterized by chalcocite and minor covellite, as well as their oxidized counterparts in the upper portions of the chalcocite blankets, which are typically replaced by copper sulphates and accessory copper carbonates. the leached cap is of the hematitic type, characterized by limonitic iron oxides and kaolinite. this mass balance study allowed reconstruction of the original geometry of the hypogene system, which is incomplete to the southeast because it is possibly interrupted and displaced along the milpillas oeste fault. the estimation of the total heights of the original leached column and the eroded leached column, were
Hematite, Biotite and Cinnabar on the Face of the Turin Shroud: Microscopy and SEM-EDX Analysis  [PDF]
Gérard Lucotte, Thierry Derouin, Thierry Thomasset
Open Journal of Applied Sciences (OJAppS) , 2016, DOI: 10.4236/ojapps.2016.69059
Abstract: The Turin Shroud, recently accessible for hands-on scientific research, is now extensively investigated. Its pinkish red blood stains that seem anomalous ones are studied by modern techniques (notably by resolute optical microscopy and scanning electron microscopy coupled with energy dispersive X-ray). Exploration by these techniques of a blood stain located on the face permits us to discover some red-colour particles (hematite, biotite and cinnabar) of exogenous material in this stain. We finally characterize these red-colour particles and try to explain their presences in the blood stain. Globally, all these red-colour particles cannot explain all of the reddish appearance of the area under study.
Rese a de "Querido novio. Cartas, escritura y contextos culturales" de Sarah Corona Berkin
José Luis Valencia Valencia
Comunicación y sociedad , 2007,
Abstract:
Discrete Evolutionary Genetics: Multiplicative Fitnesses and the Mutation-Fitness Balance  [PDF]
Thierry Huillet, Servet Martinez
Applied Mathematics (AM) , 2011, DOI: 10.4236/am.2011.21002
Abstract: We revisit the multi-allelic mutation-fitness balance problem especially when fitnesses are multiplicative. Using ideas arising from quasi-stationary distributions, we analyze the qualitative differences between the fitness-first and mutation-first models, under various schemes of the mutation pattern. We give some stochastic domination relations between the equilibrium states resulting from these models.
Energy and Emergy Analysis to Evaluate Sustainability of Small Wastewater Treatment Plants: Application to a Constructed Wetland and a Sequencing Batch Reactor  [PDF]
Gerard Merlin, Thierry Lissolo
Journal of Water Resource and Protection (JWARP) , 2010, DOI: 10.4236/jwarp.2010.212120
Abstract: The aim of this study is to assess the sustainability of two wastewater treatment systems by energy and emergy analyses. The first system is a Sequencing Batch Reactor (SBR) which is a concrete and electricity dependent intensive process. The second is a constructed wetland, usually considered as an extensive process. The two studied facilities have similar treatment capacity and removal efficiencies. This study sheds new light on the comparison of wastewater treatment plants. We defined a new unit, the “Functional Efficiency Index” (or FEI) to describe the energetic efficiency of the facilities, expressed in kJ per year and per kg of removed COD. The energy analysis showed that, after its construction, the constructed wetland system uses only renewable energy, in marked contrast to the SBR, totally dependent on electricity which is considered here as a non renewable. The emergy analysis showed no significant differences between the two processes, but energy and emergy indices are in favour of the constructed wetland process and thus confirm its sustainability.
Improving Rwandan Criminal Justice through Forensic DNA Evidence: An Appraisal  [PDF]
Murangira B. Thierry
Beijing Law Review (BLR) , 2016, DOI: 10.4236/blr.2016.74032
Abstract: At present, the utility of forensic evidence has acquired admissibility in the area of criminal justice. This utility has been applied in various legal systems worldwide; wherein scientific evidence such as DNA helps the courts to decide complicated high-tech crime cases. Scientific evidence such as DNA is a tool used to ascertain the guilt or innocence of suspect with certainty when evidence such as blood, semen have been left at crime scene. It plays a duo role either to exonerate individual falsely accused or convict those guilty of crimes. DNA evidence is normally used to resolve criminal case in various ways. The first scenario is when the suspect is known and DNA sample collected from him/her is compared from the DNA sample collected from the scene of crime to ascertain the involvement of suspect in commission of crime. The second one is when the suspect is unknown but he/she leaves the biological evidence at the crime scene where these evidence can be analysed and compared with perpetrator’s DNA profile from DNA database to establish his/her identity. Moreover, through the use of DNA profile from database, DNA evidence collected from crime scene when the originator is unidentified be utilised to link other already committed crimes. In these circumstances, DNA technology is increasingly vital to safeguard correctness and objectivity in crime solving. Its use in Rwandan criminal justice system has not yet yielded significant impact on administration of justice. This is due to the fact that in criminal justice, forensic science in general and DNA technology in particular are still at infant stage and have not yet been introduced as subject in any law curriculum; lack of specific DNA legislation is another stumbling block wherein DNA evidence is considered as circumstantial evidence with minor consideration. It is the time wherein all actors of justice and all stakeholders (criminal justice chain and law colleges) should realize that this genetic evidence is a powerful and helpful tool for securing prosecution as well as helping to eliminate suspects early in investigation and increase prosecution rate, hence giving justice. The enactment of specific DNA legislation will guide the Investigators and Prosecutors in conducting investigation and prosecution and also the Judges in directing or evaluating DNA tests. For these reasons, DNA evidence and database need to be legally recognized through such new legislation and DNA technology be introduced in law colleges. This is one of mechanisms to break the circle of lack of awareness, admissibility of DNA
Multiple Sequence Alignments as Tools for Protein Structure and Function Prediction
Alfonso Valencia
Comparative and Functional Genomics , 2003, DOI: 10.1002/cfg.313
Abstract: Multiple sequence alignments have much to offer to the understanding of protein structure, evolution and function. We are developing approaches to use this information in predicting protein-binding specificity, intra-protein and protein-protein interactions, and in reconstructing protein interaction networks.
DEL ANáLISIS CRíTICO DEL DISCURSO Y LAS IDEOLOGíAS
Valencia,Carlos;
Forma y Función , 2011,
Abstract: as a social practice, discourse allows for the concrete expression of the opinions and beliefs that a person or group may have regarding a fact, a situation, or another social group. this makes discourse an effective mechanism for socialization, which can be used to reproduce and endorse ideologies, understood as concepts that include a social and a subjective dimension. therefore, while values or ideals are systems of beliefs expressed in tradition, they are also cognitive structures that build individual thought and action patterns. it is precisely this subjective dimension that grants discourse greater power and symbolic efficacy, since the meaning of human experiences is determined by social interactions, which are ultimately communicative acts that take place in the symbolic world of language. thus, discourse and ideology are intimately linked.
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