125 research outputs found

    Coherently manipulating flying qubits in a quantum wire with a magnetic impurity

    Full text link
    e study the effect of a magnetic impurity with spin-half on a single propagating electron in a one-dimensional model system via the tight-binding approach. Due to the spin-dependent interaction, the scattering channel for the flying qubit is split, and its transmission spectrum is obtained. It is found that, the spin orientation of the impurity plays the role as a spin state filter for a flying qubit.Comment: 6 pages, 5 figure

    A container orchestration development that optimizes the etherpad collaborative editing tool through a novel management system

    Full text link
    The use of collaborative tools has notably increased recently. It is common to see distinct users that need to work simultaneously on shared documents. In most cases, large companies provide tools whose implementations have been a very complicated and expensive task. Likewise, their platform deployment requirements should be robust hardware infrastructures. It becomes even more critical when their main target is to reach scalability and highavailability. Therefore, this study aims to design and implement a microservices-based collaborative architecture using assembled containers in the cloud, enabling them to deploy Etherpad instances to guarantee high availability. To ensure such a task, we developed and optimized a central management system that creates Etherpad instances and continuously interacts with other Etherpad tools running on Docker containers. This design goes from the monolithic Etherpad instantiation and handling towards a service architecture, where every Etherpad is offered as a microservice. Furthermore, the management system follows (implements) the Observer, Factory Method, Proxy, and Service Layerpopular design patterns. This allows users to gain more privacy through access to validations and shared resources. Our results indicate both the correct operation in the automation of containers’ creation for new users who register in the system and quantifiable improvement in performance.The funding of this research is provided by the Mobility Regulation of the Universidad de las Fuerzas Armadas ESPE, from Sangolquí, Ecuado

    Variation in calcification of Reticulofenestra coccoliths over the Oligocene–Early Miocene

    Get PDF
    Coccolithophores are calcifying marine phytoplankton whose intracellularly produced calcite plates, coccoliths, have been the dominant source of calcium carbonate in open-ocean settings since the Cretaceous. An open question is whether their calcification has been affected by changing environmental conditions over geological timescales such as variations in the ocean carbon system. Previous methods using circular polarized light microscopy allowed for only the thickness of small coccoliths thinner than 1.5 µm to be quantified, but prior to the Pliocene, a significant fraction of the coccoliths exceeded this thickness and have not been quantifiable. Here, we implement a new approach for calibration of circular polarized light microscopy enabling us to quantify coccoliths which feature calcite up to 3 µm thick. We apply this technique to evaluate the evolution of calcification in the Reticulofenestra from the early Oligocene to Early Miocene in exceptionally well-preserved sediments from the Newfoundland margin. Through this time interval, coccolith thickness and the scale-invariant shape factor kse vary by about 20 % around the mean thickness of 0.37 µm and mean kse of 0.16. Lower shape factors characterize samples with a higher relative abundance of dissolution-resistant nannoliths, suggesting that dissolution may contribute to thinning of placoliths. We therefore define temporal trends in calcification only in samples in which the assemblage suggests minimal dissolution. The lowest kse characterizes the middle Oligocene, and the highest kse around 18 Ma is in the Early Miocene. High ocean dissolved inorganic carbon (DIC) concentrations have been proposed for this period of the Miocene and may be one factor contributing to high coccolith kse.</p

    Biophysical analysis of the MHR motif in folding and domain swapping of the HIV capsid protein C-terminal domain

    Get PDF
    © 2015 Biophysical Society. Infection by human immunodeficiency virus (HIV) depends on the function, in virion morphogenesis and other stages of the viral cycle, of a highly conserved structural element, the major homology region (MHR), within the carboxyterminal domain (CTD) of the capsid protein. In a modified CTD dimer, MHR is swapped between monomers. While no evidence for MHR swapping has been provided by structural models of retroviral capsids, it is unknown whether it may occur transiently along the virus assembly pathway. Whatever the case, the MHR-swapped dimer does provide a novel target for the development of anti-HIV drugs based on the concept of trapping a nonnative capsid protein conformation. We have carried out a thermodynamic and kinetic characterization of the domain-swapped CTD dimer in solution. The analysis includes a dissection of the role of conserved MHR residues and other amino acids at the dimerization interface in CTD folding, stability, and dimerization by domain swapping. The results revealed some energetic hotspots at the domain-swapped interface. In addition, many MHR residues that are not in the protein hydrophobic core were nevertheless found to be critical for folding and stability of the CTD monomer, which may dramatically slow down the swapping reaction. Conservation of MHR residues in retroviruses did not correlate with their contribution to domain swapping, but it did correlate with their importance for stable CTD folding. Because folding is required for capsid protein function, this remarkable MHR-mediated conformational stabilization of CTD may help to explain the functional roles of MHR not only during immature capsid assembly but in other processes associated with retrovirus infection. This energetic dissection of the dimerization interface in MHR-swapped CTD may also facilitate the design of anti-HIV compounds that inhibit capsid assembly by conformational trapping of swapped CTD dimers.Spanish Government (BIO2012-37649) and Comunidad de Madrid (S-2009/MAT/1467) and by an institutional grant from Fundación Ramón Areces.Peer Reviewe

    Sexual abuse vs. sexual freedom? A legal Approach to the Age of Sexual Consent in Adolescents in Spanish-Speaking Countries

    Get PDF
    Child and adolescent sexual abuse (CSA) is an international public health problem. Despite the importance of CSA, there is no consensus definition, and the lack of consensus is related to difficulties in conducting prevalence studies as well as research in other areas. To establish a consensual definition, legal aspects such as the age of sexual consent and the difference in age or power between victim and aggressor as well as aspects related to sexual freedom and sexual indemnity must be considered. Therefore, the main goal of this research was to analyze the age of sexual consent in the legal systems of Spanish-speaking countries and to examine whether the Romeo and Juliet clause is established. To achieve the proposed aims, we employed the legal interpretation method, and we analyzed the current Criminal Codes of the 21 Spanish-speaking countries. From the results, it is found that the age of sexual consent varies between countries, establishing valid sexual consent between 13 and 18 years. In addition, only six countries have the Romeo and Juliet clause that protects sexual freedom in adolescents. Finally, we discussed the lack of consensus on the age of sexual consent and the limitations presented by the Romeo and Juliet clause

    Highly fluorescent complexes with 3-isocyanoperylene and N-(2,5-di-tert-butylphenyl)-9-isocyano-perylene- 3,4-dicarboximide

    Get PDF
    Producción CientíficaThe perylene derivatives 3-isocyanoperylene (Per–N≡C) (4a) and N-(2,5-di-tert-butylphenyl)- 9-isocyano-perylene-3,4-dicarboximide (PMI–N≡C) (4b) were prepared and used to synthesize gold complexes [AuX(CNR)] (X = C6F5 (5a,b), C6F4-OnBu-p (6b)). The reaction of 5b and 6b with HNEt2 led the carbene complexes [AuX{C(NEt2)(NHR)}] (7b, 8b), respectively. The molecular structure of complexes 7b, 8b have been determined by X-ray diffraction analysis showing intermolecular π–stacking of the perylene groups and C6F5 rings, and no Au···Au interactions. The derivative compounds [M(CO)5(CNR)] (M = Cr (9a,b), Mo (10a,b) or W (11a,b)) and trans-[Pd(CNR)2(C6F3Cl2)2] (12a,b) were also prepared. All complexes exhibit fluorescence associated to the perylene fragment with emission quantum yields, in solution at room temperature, in the range 0.05 – 0.93 and emission lifetimes ~ 4 ns. DFT calculations were performed of the absorption spectra of the ligands Per–N≡C and PMI–N≡C, and representative complexes [Au(C6F5)(CNR)], [Cr(CO)5(CNR)], showing a perylene-dominated intraligand π–π*emissive state, from the HOMO and LUMO orbitals of the perylene chromophore, but with significantly different absorption maxima by influence of the metal fragment, particularly significant in the Per–N≡C derivatives.Ministerio de Economía, Industria y Competitividad (CTQ2011-2513)Ministerio de Economía, Industria y Competitividad (CTQ2011-23862-C02)Junta de Castilla y León (programa de apoyo a proyectos de investigación – Ref. VA302U13)Generalitat de Catalunya (grant 2009SGR-1459

    Higher fluorescence in platinum(IV) orthometallated complexes of perylene imine compared with their platinum(II) or palladium(II) analogues

    Get PDF
    Producción CientíficaThe reaction of 3-perylenylmethylen-4'-ethylaniline () with [Pt2Me4(μ-SMe2)2] (and subsequent addition of PPh3) or with [Pt2(η(3)-C4H7)2(μ-Cl)2] produced cyclometallated Pt(II) complexes [Pt(C^N)Me(PPh3)] () and, respectively, [Pt2(C^N)2(μ-Cl)2] () (HC^N = 3-C20H11CH[double bond, length as m-dash]NC6H4-p-C2H5), with Pt bound to the ortho site of the perylenyl fragment. From the mononuclear complexes [Pt(C^N)L2] (L2 = acac (); S2COMe (); S2CNEt2 () are easily formed. Oxidative addition of methyl iodide to the square-planar Pt(II) complexes , , and gave the corresponding cyclometallated Pt(IV) compounds [Pt(C^N)L2MeI] , and . The X-ray structures of , , and show that the perylenyl fragment remains essentially flat in and and slightly twisted in . Comparison of the optical properties of these Pt(II) complexes with those reported for similar Pd(II) derivatives reveals that the change of metal exerts a notable influence on the UV-vis spectra. In solution at room temperature, all the Pt complexes exhibit fluorescence associated with the perylene fragment with low emission quantum yields for the Pt(II) complexes (<1%) and remarkably higher emission values for the Pt(IV) complexes: up to 29%, with emission lifetimes of 1-5 ns. Time-dependent density functional theory (TD-DFT) calculations were performed on the perylene imine and on representative complexes [M(C^N)(acac)] (M = Pd, Pt) and [Pt(C^N)(acac)MeI] to analyse the absorption spectra. These calculations support a perylene-dominated intraligand π-π*emissive state based on the HOMO and LUMO orbitals of the perylene chromophore, and a ligand-to-ligand charge-transfer (more intense for the Pt(II) complex) that explains the observed influence of the metal on the absorption properties.Ministerio de Economía, Industria y Competitividad (CTQ2014-52796-P)Junta de Castilla y León (programa de apoyo a proyectos de investigación – Ref. VA302U13

    Infraestructura común de telecomunicación

    Get PDF
    Realización de la infraestructura común de telecomunicación o ICT de un edificio de 6 planta de obra nueva, con 2 locales (planta baja), 2 oficinas (planta 1ª) y 15 viviendas (plantas 2ª-6ª)
    corecore