56 research outputs found

    ¿Qué hacemos con nuestro hotel?

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    Case study of a luxury hotel built in downtown Cusco in the late 1940s, when tourism in that city gained great momentum due to the global spread of the archaeological heritage located nearby. The business was success, but in the 1970s demand and revenues began to decline. The situation did not improve until 1993, when after years of accumulated debts, the hotel began to recover income, which allowed it to stay without major investments. Shortly after, the owner passed away, leaving a dilapidated hotel for his three sons. Now they must decide what to do with the hotel: sell it, rent it or operate it themselves or in association with another company. Unable to reach an agreement, they hire specialist consultants in the field to make a better decision. The case includes financial information and a summary of the consulting firm's study.Estudio de caso de un hotel de lujo construido en el centro del Cusco a finales de la década de 1940, cuando el turismo en esa ciudad cobró gran impulso debido a la difusión global del patrimonio arqueológico ubicado en sus cercanías. El negocio fue un éxito, pero en la década de 1970 la demanda y los ingresos comenzaron a disminuir. La situación no mejoró hasta 1993, cuando tras años de deudas acumuladas, el hotel empezó a recuperar ingresos, lo que le permitió mantenerse sin grandes inversiones. Poco después, el propietario falleció, dejando un hotel en ruinas para sus tres hijos. Ahora deben decidir qué hacer con el hotel: venderlo, alquilarlo u operarlo ellos mismos o en asociación con otra empresa. Al no poder llegar a un acuerdo, contratan consultores especialistas en la materia para tomar una mejor decisión. El caso incluye información financiera y un resumen del estudio de la consultora

    Encuesta sobre política y cultura

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    Encuestas realizadas a importantes figuras peruanas de la cultura para examinar las vinculaciones que se dan o deberían dar en el Perú entre la política y la cultura.This article contains surveys to important cultural figures of Peru to examine the real and ideal links between politics and culture in the country

    Âge K/Ar et contrôle structural de mise en place des veines épithermales à Au-Ag de la Cordillera Shila, Sud Pérou.

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    International audienceThe Au-Ag epithermal mineralization of the Shila Cordillera is dated at about 10.7 Ma (K/Ar on adularia). The vein system is characterized by the association of a major east-west vein and N120-135°E secondary fractures. The strike-slip faults controlling the veins indicate an initial NE-SW to ENE-WSW shortening direction, which is compatible with that generally accepted for this period. These structures were reopened during a second phase and channelized mineralizing fluids, the circulation of which may have began at the end of stage 1.Les minéralisations épithermales à Au-Ag de la Cordillera Shila sont datées à environ 10,7 Ma (K/Ar sur adulaire). Le système de veines est caractérisé par l'association entre une veine principale sensiblement est-ouest et des fractures satellites N120 à N135°E. Les décrochements contrôlant les veines indiquent une direction de raccourcissement initiale NE-SW à ENE-WSW, compatible avec celle généralement admise pour cette période. Dans un deuxième stade, ces structures sont ré-ouvertes pour servir de réceptacle aux fluides minéralisateurs, dont la circulation débute probablement dès la fin du stade 1

    Modelo de Análisis de las decisiones de Inversión y sus Efectos en la Valorización Empresarial: Caso Graña y Montero S.A.A. 2005 – 2019

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    El presente trabajo de investigación denominado “Modelo de análisis de las decisiones de inversión y sus efectos en la valorización empresarial: Caso Graña y Montero S.A.A. 2005-2019”, tiene como objetivo determinar un modelo estructurado de la gestión y desempeño de la compañía para determinar su influencia en el valor empresarial de la misma. La compañía Graña y Montero se encuentra dentro del sector construcción, siendo este uno de los más importantes dentro del país, representando una fuente de ingresos para el país y generador de empleos. Dentro de él la compañía es una de las más representativas por su posicionamiento nacional e internacional apoyado por su crecimiento y su gestión en diferentes proyectos. En el primer trimestre del 2017 el valor de la acción cayó generando incertidumbre en los inversionistas. Basándonos en esa problemática surge el hecho de establecer un modelo de valoración que refleje la influencia de sus decisiones de inversión en su valor empresarial en el entorno donde se desempeña la compañía. Por ello estructuramos un modelo que incluyera los indicadores directos que evalúan su gestión en el mercado donde realizan sus operaciones. En un principio establecimos el procedimiento para la integración de los modelos en uno solo. Este modelo nos mostró resultados que evaluaban a la compañía de manera precisa. Al final obtuvimos un valor empresarial de acuerdo a su gestión histórica y proyectada, que demuestra su desempeño en el mercado actual. Palabras Clave: Decisiones de Inversión, Valor Empresarial, Graña y Montero, Modelo de valoración, Construcción.Tesi

    Internal vein texture and vein evolution of the epithermal Shila-Paula district, southern Peru.

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    The epithermal Shila-Paula Au–Ag district is characterized by numerous veins hosted in Tertiary volcanic rocks of the Western Cordillera (southern Peru). Field studies of the ore bodies reveal a systematic association of a main E–W vein with secondary N55–60°W veins—two directions that are also reflected by the orientation of fluid-inclusion planes in quartz crystals of the host rock. In areas where this pattern is not recognized, such as the Apacheta sector, vein emplacement seems to have been guided by regional N40°E and N40°W fractures. Two main vein-filling stages are identified. stage 1 is a quartz–adularia–pyrite–galena–sphalerite–chalcopyrite–electrum–Mn silicate–carbonate assemblage that fills the main E–W veins. stage 2, which contains most of the precious-metal mineralization, is divided into pre-bonanza and bonanza substages. The pre-bonanza substage consists of a quartz–adularia–carbonate assemblage that is observed within the secondary N45–60°W veins, in veinlets that cut the stage 1 assemblage, and in final open-space fillings. The two latter structures are finally filled by the bonanza substage characterized by a Fe-poor sphalerite–chalcopyrite–pyrite–galena–tennantite–tetrahedrite–polybasite–pearceite–electrum assemblage. The ore in the main veins is systematically brecciated, whereas the ore in the secondary veins and geodes is characteristic of open-space crystallization. Microthermometric measurements on sphalerite from both stages and on quartz and calcite from stage 2 indicate a salinity range of 0 to 15.5 wt% NaCl equivalent and homogenization temperatures bracketed between 200 and 330°C. Secondary CO2-, N2- and H2S-bearing fluid inclusions are also identified. The age of vein emplacement, based on 40Ar/39Ar ages obtained on adularia of different veins, is estimated at around 11 Ma, with some overlap between adularia of stage 1 (11.4±0.4 Ma) and of stage 2 (10.8±0.3 Ma). A three-phase tectonic model has been constructed to explain the vein formation. Phase 1 corresponds to the assumed development of E–W sinistral shear zones and associated N60°W cleavages under the effects of a NE–SW shortening direction that is recognized at Andean scale. These structures contain the stage 1 ore assemblage that was brecciated during ongoing deformation. Phase 2 is a reactivation of earlier structures under a NW–SE shortening direction that allowed the reopening of the preexisting schistosity and the formation of scarce N50°E-striking S2-cleavage planes filled by the stage 2 pre-bonanza minerals. Phase 3 coincides with the bonanza ore emplacement in the secondary N45–60°W veins and also in open-space in the core of the main E–W veins. Our combined tectonic, textural, mineralogical, fluid-inclusion, and geochronological study presents a complete model of vein formation in which the reactivation of previously formed tectonic structures plays a significant role in ore formation

    Substrate translocation involves specific lysine residues of the central channel of the conjugative coupling protein TrwB

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    Conjugative transfer of plasmid R388 requires the coupling protein TrwB for protein and DNA transport, but their molecular role in transport has not been deciphered. We investigated the role of residues protruding into the central channel of the TrwB hexamer by a mutational analysis. Mutations affecting lysine residues K275, K398, and K421, and residue S441, all facing the internal channel, affected transport of both DNA and the relaxase protein in vivo. The ATPase activity of the purified soluble variants was affected significantly in the presence of accessory protein TrwA or DNA, correlating with their behaviour in vivo. Alteration of residues located at the cytoplasmic or the inner membrane interface resulted in lower activity in vivo and in vitro, while variants affecting residues in the central region of the channel showed increased DNA and protein transfer efficiency and higher ATPase activity, especially in the absence of TrwA. In fact, these variants could catalyze DNA transfer in the absence of TrwA under conditions in which the wild-type system was transfer deficient. Our results suggest that protein and DNA molecules have the same molecular requirements for translocation by Type IV secretion systems, with residues at both ends of the TrwB channel controlling the opening?closing mechanism, while residues embedded in the channel would set the pace for substrate translocation (both protein and DNA) in concert with TrwA

    Design of Novel Relaxase Substrates Based on Rolling Circle Replicases for Bioconjugation to DNA Nanostructures

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    During bacterial conjugation and rolling circle replication, HUH endonucleases, respectively known as relaxases and replicases, form a covalent bond with ssDNA when they cleave their target sequence (nic site). Both protein families show structural similarity but limited amino acid identity. Moreover, the organization of the inverted repeat (IR) and the loop that shape the nic site differs in both proteins. Arguably, replicases cleave their target site more efficiently, while relaxases exert more biochemical control over the process. Here we show that engineering a relaxase target by mimicking the replicase target, results in enhanced formation of protein-DNA covalent complexes. Three widely different relaxases, which belong to MOBF, MOBQ and MOBP families, can properly cleave DNA sequences with permuted target sequences. Collaterally, the secondary structure that the permuted targets acquired within a supercoiled plasmid DNA resulted in poor conjugation frequencies underlying the importance of relaxase accessory proteins in conjugative DNA processing. Our results reveal that relaxase and replicase targets can be interchangeable in vitro. The new Rep substrates provide new bioconjugation tools for the design of sophisticated DNA-protein nanostructures.This work was financed by grants BFU2014-55534-C2-1-P from the Spanish Ministry of Economy and Competitiveness and 612146/FP7-ICT- 2013 and 282004/FP7-HEALTH.2011.2.3.1-2 from the European Union Seventh Framework Programme to FC and grant BFU2014-55534-C2-2-P from the Spanish Ministry of Economy and Competitiveness to GM. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

    The repertoire of ICE in prokaryotes underscores the unity, diversity, and ubiquity of conjugation

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    Horizontal gene transfer shapes the genomes of prokaryotes by allowing rapid acquisition of novel adaptive functions. Conjugation allows the broadest range and the highest gene transfer input per transfer event. While conjugative plasmids have been studied for decades, the number and diversity of integrative conjugative elements (ICE) in prokaryotes remained unknown. We defined a large set of protein profiles of the conjugation machinery to scan over 1,000 genomes of prokaryotes. We found 682 putative conjugative systems among all major phylogenetic clades and showed that ICEs are the most abundant conjugative elements in prokaryotes. Nearly half of the genomes contain a type IV secretion system (T4SS), with larger genomes encoding more conjugative systems. Surprisingly, almost half of the chromosomal T4SS lack co-localized relaxases and, consequently, might be devoted to protein transport instead of conjugation. This class of elements is preponderant among small genomes, is less commonly associated with integrases, and is rarer in plasmids. ICEs and conjugative plasmids in proteobacteria have different preferences for each type of T4SS, but all types exist in both chromosomes and plasmids. Mobilizable elements outnumber self-conjugative elements in both ICEs and plasmids, which suggests an extensive use of T4SS in trans. Our evolutionary analysis indicates that switch of plasmids to and from ICEs were frequent and that extant elements began to differentiate only relatively recently. According to the present results, ICEs are the most abundant conjugative elements in practically all prokaryotic clades and might be far more frequently domesticated into non-conjugative protein transport systems than previously thought. While conjugative plasmids and ICEs have different means of genomic stabilization, their mechanisms of mobility by conjugation show strikingly conserved patterns, arguing for a unitary view of conjugation in shaping the genomes of prokaryotes by horizontal gene transfer

    A degenerate primer MOB typing (DPMT) method to classify gamma-proteobacterial plasmids in clinical and environmental settings

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    Transmissible plasmids are responsible for the spread of genetic determinants, such as antibiotic resistance or virulence traits, causing a large ecological and epidemiological impact. Transmissible plasmids, either conjugative or mobilizable, have in common the presence of a relaxase gene. Relaxases were previously classified in six protein families according to their phylogeny. Degenerate primers hybridizing to coding sequences of conserved amino acid motifs were designed to amplify related relaxase genes from γ-Proteobacterial plasmids. Specificity and sensitivity of a selected set of 19 primer pairs were first tested using a collection of 33 reference relaxases, representing the diversity of γ-Proteobacterial plasmids. The validated set was then applied to the analysis of two plasmid collections obtained from clinical isolates. The relaxase screening method, which we call "Degenerate Primer MOB Typing" or DPMT, detected not only most known Inc/Rep groups, but also a plethora of plasmids not previously assigned to any Inc group or Rep-type
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