Quantum Error Correction with magnetic molecules

Quantum algorithms often assume independent spin qubits to produce trivial $|\uparrow\rangle=|0\rangle$, $|\downarrow\rangle=|1\rangle$ mappings. This can be unrealistic in many solid-state implementations with sizeable magnetic interactions. Here we show that the lower part of the spectrum of a molecule containing three exchange-coupled metal ions with $S=1/2$ and $I=1/2$ is equivalent to nine electron-nuclear qubits. We derive the relation between spin states and qubit states in reasonable parameter ranges for the rare earth $^{159}$Tb$^{3+}$ and for the transition metal Cu$^{2+}$, and study the possibility to implement Shor's Quantum Error Correction code on such a molecule. We also discuss recently developed molecular systems that could be adequate from an experimental point of view.Comment: 5 pages, 3 figures, 2 table

Manifestaciones orales en la histiocitosis crónica diseminada: presentación de 10 casos

La histiocitosis crónica diseminada es una enfermedad sistémica por proliferación tumoral de células histiocitarias tipo Langerhans. Su etiología y patogenia no esta del todo aclarada y las manifestaciones clínicas se producen por acúmulos e infiltrados de este tipo celular en los tejidos y órganos. Presentamos 10 pacientes, seis niños y cuatro niñas, con histiocitosis crónica diseminada. La edad de aparición de la enfermedad varió desde los 4 meses hasta los 3'2 años, con una edad media de 1'7 años. Todos los pacientes presentaron lesiones orales y en 5 de ellos éstas fueron la manifestación inicial de la enfermedad. Las alteraciones más frecuentes fueron: sangrado gingival (7 casos), aftas mayores de 1cm de diámetro (6 casos), alteraciones osteolíticas de los maxilares (6 casos), pérdida de dientes por foliculitis expulsiva (5 casos), candidiasis oral (4 casos), tumefacción orofacial (3 casos), aftas menores de 1 cm (3 casos) y dolores orales inespecíficos (2 casos). Todas las lesiones bucales desaparecieron con los tratamientos utilizados a pesar de que algunos casos presentaron nuevos brotes y exacerbaciones de la enfermedad.Chronic disseminated histiocytosis is a systemic disorder resulting from tumor proliferation of Langerhans-type histiocytic cells. The etiology and pathogenesis are not fully clear, though the clinical manifestations are the result of the accumulation and infiltration of these types of cells in organs and tissues. The present study reports 10 patients (6 boys and 4 girls) with chronic disseminated histiocytosis. The patient age at onset of the disease varied from 4 months to 3.2 years (mean 1.7 years). All patients had oral lesions, and in 5 cases these were the first manifestation of the disease. The most frequent alterations were gingival bleeding (7 cases), aphthae measuring over 1 cm in diameter (6 cases), maxillary osteolytic lesions (6 cases), tooth loss due to expulsive folliculitis (5 cases), oral candidiasis (4 cases), orofacial swelling (3 cases), aphthae measuring under 1 cm in diameter (3 cases), and nonspecific oral pain (2 cases). All the oral lesions disappeared with the treatments prescribed, though some patients developed new outbreaks and exacerbations of the disease

The variation of export prices across and within firms

Incluye bibliografíaEste trabajo utiliza datos individuales de transacciones comerciales para analizar las diferencias en los precios de exportación entre empresas y dentro de cada empresa con una muestra de compañías manufactureras españolas para el año 2014. La naturaleza transaccional de la base de datos revela importantes diferencias en el precio que el exportador carga a un mismo producto y destino. Estas diferencias están relacionadas con el número de bienes comerciados dentro de cada categoría de producto, los descuentos por volumen, y el grado de diferenciación vertical de las variedades de producto. Por su parte, los precios de las exportaciones están positivamente correlacionados con la productividad de las empresas, el PIB per cápita de los mercados de destino y su distancia a España. Estos últimos resultados sugieren que los exportadores españoles compiten en calidadThis paper uses transaction-level trade data to analyse the differences in export prices across and within Spanish manufacturing firms in the year 2014. The transactional nature of the database uncovers sizable differences in the price that an exporter charges for the same product and destination. These differences are related to the number of goods covered within each product category, volume discounts and vertically differentiated varieties. Export prices are positively correlated with firms’ productivity, destination markets’ GDP per capita and distance to Spain. These latter results suggest that Spanish exporters compete in qualit

The variation of export prices across and within firms

This paper uses transaction-level trade data to analyze the differences in export prices across and within Spanish firms exporting manufactures in the 2010-2014 period. The transactional nature of the database uncovers sizable differences in the price that an exporter charges for the same product and destination. These differences are related with the number of goods covered within each product category, the exported quantity per transaction and the number of transactions carried out by firms

The contribution of granular and fundamental comparative advantage to European Union countries' export specialisation

This paper analyzes the contribution of fundamental comparative advantage (a country-speci c component) and granular comparative advantage (a rm-speci c component) to European Union countries' export specialization. We nd that, on average, granular comparative advantage may explain export specialization in 29% of industries, which account for 47% of total exports. We also show that 60% of the variation in export specialization across countries and industries may be explained by granular comparative advantage. These results highlight that some outstanding rms may play a very important role in explaining European Union countries' export specialization.Ministerio de Economía y CompetitividadGobierno VascoGeneralitat Valencian

Do firms react to supply chain disruptions?

Since the outbreak of the Covid-19 pandemic, the disruption of supply chains has become a major concern for global firms. This article uses a representative sample of Spanish manufacturers that participate in global value chains to analyze whether firms are implementing strategies to respond to this concern. Using data for the period 2017?2022, we find that, on average, manufacturers have not increased the number of countries from which they source their input since the Covid-19 pandemic. Firms have not either shifted their imports to countries that are geographically and geopolitically close to Spain, and have not reshored imports. However, firms have significantly increased the stock of intermediates. Firms only diversify when they have one supplier, export to many destinations, and the imported input has a high risk of experiencing a supply chain disruption. Firms nearshore and friendshore when their main supplier is geographically distant.Ministerio de Ciencia e InnovaciónGobierno Vasco. Departamento de EducaciónComunidad de MadridGeneralitat Valencian

Keratitis after Implantation of Intrastromal Corneal Rings with Spontaneous Extrusion of the Segment

Purpose: To report a case of bacterial keratitis in a patient with a history of intrastromal corneal ring segments (INTACS®) implantation to correct keratoconus. Methods: The patient’s history, clinical presentation, pathological analysis and therapeutic management were reviewed. Results: A 36-year-old-man was referred to our department due to decreased vision and intense pain in his left eye, 40 days after INTACS® implantation for keratoconus. Slit-lamp examination revealed epithelial defects and stromal infiltrates in the lower channel without evidence of the inferior ring. The anterior chamber also showed a significant fibrin reaction to hypopyon. A low-tension suture was removed at the site of the incision. Microbiological study of the conjunctival swab was positive for Staphylococcus epidermidis, but the corneal culture was sterile. The patient was treated with topical fortified and systemic antibiotics. The infection slowly resolved, leaving opacity at the inferior segment site. Conclusions: Infectious keratitis following INTACS implantation is an infrequent complication that can have important consequences without suitable and early therapeutic management

Cobalt Metal-Organic Framework based on two dinuclear secondary building units for electrocatalytic oxygen evolution

The synthesis of a new microporous metal-organic framework (MOF) based on two secondary building units, with dinuclear cobalt centers, has been developed. The employment of a well-defined cobalt cluster results in an unusual topology of the Co2-MOF, where one of the cobalt centers has three open coordination positions, which has no precedent in MOF materials based on cobalt. Adsorption isotherms have revealed that Co2-MOF is in the range of best CO2 adsorbents among the carbon materials, with very high CO2/CH4 selectivity. On the other hand, dispersion of Co2-MOF in an alcoholic solution of Nafion gives rise to a composite (Co2-MOF@Nafion) with great resistance to hydrolysis in aqueous media and good adherence to graphite electrodes. In fact, it exhibits high electrocatalytic activity and robustness for the oxygen evolution reaction (OER), with a turnover frequency number value superior to those reported for similar electrocatalysts. Overall, this work has provided the basis for the rational design of new cobalt OER catalysts and related materials employing well-defined metal clusters as directing agents of the MOF structure

Cobalt metal-organic framework based on layered double nanosheets for enhanced electrocatalytic water oxidation in neutral media

A new cobalt metal-organic framework (2D-Co-MOF) based on well-defined layered double cores that are strongly connected by intermolecular bonds has been developed. Its 3D structure is held together by π-π stacking interactions between the labile pyridine ligands of the nanosheets. In aqueous solution, the axial pyridine ligands are exchanged by water molecules, producing a delamination of the material, where the individual double nanosheets preserve their structure. The original 3D layered structure can be restored by a solvothermal process with pyridine, so that the material shows a "memory effect" during the delamination-pillarization process. Electrochemical activation of a 2D-Co-MOF@Nafion-modified graphite electrode in aqueous solution improves the ionic migration and electron transfer across the film and promotes the formation of the electrocatalytically active cobalt species for the oxygen evolution reaction (OER). The so-activated 2D-Co-MOF@Nafion composite exhibits an outstanding electrocatalytic performance for the OER at neutral pH, with a TOF value (0.034 s-1 at an overpotential of 400 mV) and robustness superior to those reported for similar electrocatalysts under similar conditions. The particular topology of the delaminated nanosheets, with quite distant cobalt centers, precludes the direct coupling between the electrocatalytically active centers of the same sheet. On the other hand, the increase in ionic migration across the film during the electrochemical activation stage rules out the intersheet coupling between active cobalt centers, as this scenario would impair electrolyte permeation. Altogether, the most plausible mechanism for the O-O bond formation is the water nucleophilic attack to single Co(IV)-oxo or Co(III)-oxyl centers. Its high electrochemical efficiency suggests that the presence of nitrogen-containing aromatic equatorial ligands facilitates the water nucleophilic attack, as in the case of the highly efficient cobalt porphyrins

Escuelas de Segunda Oportunidad: una propuesta curricular dirigida a la reconstrucción personal, al retorno educativo y la inserción profesional

Las Escuelas de Segunda Oportunidad (E2O) aspiran a convertirse en una respuesta a los desafíos que plantea el retorno educativo y la inserción laboral de jóvenes en situación de riesgo de exclusión. El objetivo de este artículo es analizar la propuesta curricular que realizan las E2O en España. Para ello, en el año 2021 realizamos entrevistas semiestructuradas a la dirección de 24 E2O, a diez profesionales de empresas que han contratado estudiantes egresados de E2O y a nueve tutores y tutoras de centros formativos a los que se han derivado estudiantes a la finalización de su paso por E2O. También se encuestó a 351 jóvenes egresados. Los resultados han revelado que los principales puntos fuertes de las E2O son la flexibilidad curricular en el diseño del itinerario formativo y el protagonismo de los jóvenes en su elección; la relevancia de las competencias transversales y básicas, valoradas por las escuelas en igual medida que las técnico-profesionales; así como el sentido de la evaluación continua, no sancionadora, dirigida a la transformación y a la mejora. Se concluye que el currículum adaptado, flexible e integral de las E2O, contribuye a la inclusión de los jóvenes en los ámbitos personal, social, educativo y laboral. Second Chance Schools (E2C) aspire to become a response to the challenges raised by the educational return and employability of young people at risk of exclusion. The aim of this paper is to analyse the curricular proposal made by the E2C in Spain. In 2021, we conducted semi-structured interviews with the principals of 24 E2C, with ten professionals from companies that have hired graduated students from these E2C, as well as with nine mentors from schools to which students have been referred at the end of their time at E2C. We also surveyed 351 graduated youths. Results show that the main strengths of E2C are their curricular flexibility in the design of the formative itinerary and the leading role of young people in their election. Other highlights of the results are the relevance of transversal and basic competences, which are valued in the same way as the technical-professional competences by the schools; and the sense of continuous and non-sanctioning assessment, which is aimed at transformation and improvement. It is concluded that an adapted, flexi-ble and comprehensive curriculum in the E2C benefits the personal, social, educational and job inclusion of young students