Qubits in phase space: Wigner function approach to quantum error correction and the mean king problem

We analyze and further develop a new method to represent the quantum state of a system of $n$ qubits in a phase space grid of $N\times N$ points (where $N=2^n$). The method, which was recently proposed by Wootters and co--workers (Gibbons {\it et al.}, quant-ph/0401155), is based on the use of the elements of the finite field $GF(2^n)$ to label the phase space axes. We present a self--contained overview of the method, we give new insights on some of its features and we apply it to investigate problems which are of interest for quantum information theory: We analyze the phase space representation of stabilizer states and quantum error correction codes and present a phase space solution to the so--called ``mean king problem''.Comment: 18 pages, 16 figures; typos fixed, some minor corrections, figures of the circuits were change

Tratamiento de las fracturas supracondíleas de húmero con desplazamiento en niños

Se realiza un estudio retrospectivo de 188 niños con fracturas supracondíleas de húmero desplazadas tratados en nuestro Servicio durante los años 1986 a 1997 mediante reducción cerrada y enclavijamiento de la fractura con dos agujas de kirschner. Se utilizó la clasificación de Gartland para la valoración del desplazamiento de la fractura y se estudiaron los resultados tanto desde el punto de vista radiológico como clínico siguiendo los criterios de Flynn. Estos resultados fueron considerados como satisfactorios en 154 casos (82%) en el seguimiento a largo plazo. Se constató la ausencia del pulso radial en 22 casos (12%) recuperándose en todos ellos después de la reducción y estabilización de la fractura y 28 casos (15%) de lesiones neurológicas que se recuperaron en un plazo comprendido entre dos y seis meses. La secuela más frecuente fue el cúbito varo en 23 casos (12%) con escasa repercusión funcional.A retrospective study of 188 children complaining of displaced supracondylar fractures of the humerus was performed. The period of the study was 1986 to 1997 and all the fractures were treated by closed reduction and percutaneous pinning with two kirschner wires. Gartland classification was used to assess the fracture's displacement. The results were studied clinically and radiologically following Flynn criteria. In the long term follow up 154 cases (82%) were considered satisfactory. A lack of radial pulse was reported in 22 cases (12%) and in all of them a total recovery was achieved after the reduction and stabilization of the fracture. We also record 28 cases (15%) of neural injuries with full recovery between two and six months time. The most frequent permanent damage was cubitus varus in 23 cases (12%) but with little functional impairment

Improving the analytical assessment of fish stocks by providing parameters of data quality via InterCatch

The last multiannual Community program for the collection, management and use of data in the fisheries sector (Commission Decision 2008/949/EC) stated the provision of precision levels and sampling intensities of the estimates at national level. However, the unequal compliance of this standard has hindered its application in stock assessment and the consequent scientific advice. The cost-benefit analysis of a sampling program, besides addressing logistical and economic constraints, should deepen the potential of the tools currently available. This article proposes to test the calculation, provision and use in stock assessment of extensively collected precision parameters. First, sampling intensities and coefficients of variation of fisheries-dependent parameters are calculated using the COST software, a statistical tool specifically designed to quantify uncertainty in marine sampled data. Secondly, alternative ways are explored to provide precision parameters to the stock assessment coordinators by using InterCatch, the existing ICES web-based system to submit national data and compile international catch matrices. Finally, the incorporation of these precision parameters in the assessment model is tested, through a stock assessed by statistical assessment models (such as SS3) which can account for sampling errors. Thus, it will be possible to quantify how errors in input data propagate through stock assessment models to affect harvest rules, and also to help identify the most cost-effective data collections that adequately support the advisory process

New Ways for the Advanced Quality Control of Liquefied Natural Gas

[Abstract] Currently, gas chromatography is the most common analytical technique for natural gas (NG) analysis as it offers very precise results, with very low limits of detection and quantification. However, it has several drawbacks, such as low turnaround times and high cost per analysis, as well as difficulties for on-line implementation. With NG applications rising, mostly thanks to its reduced gaseous emissions in comparison with other fossil fuels, the necessity for more versatile, fast, and economic analytical methods has augmented. This work summarizes the latest advances to determine the composition and physico-chemical properties of regasified liquid natural gas, focusing on infrared spectroscopy-based techniques, as well as on data processing (chemometric techniques), necessary to obtain adequate predictions of NG properties.Part of this work was performed under the EMPIR 16ENG09 project ‘Metrological support for LNG and LBG as transport fuel (LNG III)’. This project has received funding from the EMPIR programme co-financed by the Participant States and from the European Union’s Horizon 2020 Research and Innovation programme. Mestrelab, Reganosa and Naturgy are acknowledged for hiring the services of the Group of Applied Analytical Chemistry for FTIR method development. The Program “Consolidación e Estructuración de Unidades de Investigación Competitivas” of the Galician Government (Xunta de Galicia) is also acknowledged (Grant ED431C 2021/56).Xunta de Galicia; ED431C 2021/5

Evaluación del área trabecular por digitalización de imágenes en el callo de fractura: estudio experimental

Se presenta un método de evaluación del área trabecular por medio de digitalización de imágenes de microscopía óptica. Se estudia la evolución de 20 callos de fractura en ratas de cepa Wistar, obteniendo un incremento progresivo del área trabecular desde los 14 a los 49 días, correlacionando ésta directamente con la actividad neoformativa. Se concluye proponiendo el uso de este método por su uniformidad, objetividad y reproductibilidad en todo el estudio, permitiendo la independencia del anatomopatológico.We present a method for assessment of the bone trabecular area by using optic microscope digitalized imaging. We studied 20 fracture callus performed at the tibia in Wistar rats. The bone trabecular area had a progressive increased from 14 to 49 days, post-fracture, been directly related with the neoformative activity. We propose this method because of this uniformity, objetivity and reliability. This method akows fracture repair analysis independently of the subjetivity of the pathologist

5,10,15,20-Tetra­kis(1-methyl­pyridinium-4-yl)porphyrin tetra­iodide tetra­hydrate

The asymmetric unit of the title compound, C44H38N8 2+·4I−·4H2O, comprises two halves of non-equivalent cations of 5,10,15,20-tetra­kis­(1-methyl­pyridinium)porphyrin (with the full mol­ecule of each completed by the application of inversion symmetry), four charge balancing iodide anions and four water mol­ecules of crystallization (two water mol­ecules are fully occupied and four mol­ecules have a site occupancy of 50%). The porphyrin cations are arranged into supramolecular columns parallel to the b axis, mediated by π–π [centroid–centroid distance = 3.762 (4) Å] and C—H⋯π supra­molecular inter­actions [C⋯centroid distance = 3.522 (7) Å, C—H⋯centroid = 128°], leading to the formation of columns parallel to the b axis. The close packing leads to the presence of a one-dimensional channel filled with partially occupied water mol­ecules engaged in O—H⋯O and O—H⋯I hydrogen bond

Glycine methyl ester hydro­chloride

The title compound [systematic name: (methoxy­carbonyl­meth­yl)ammonium chloride], crystallizes as a salt, C3H8NO2 +·Cl−, with the charged species inter­acting mutually via strong and highly directional N+—H⋯Cl− hydrogen bonds which lead to the formation of a supra­molecular tape running parallel to the c axis. Tapes close pack in the solid state mediated by multipoint recognition synthons based on weak C—H⋯O inter­actions and van der Waals contacts between adjacent methyl groups

5-Amino-1H-1,2,4-triazol-4-ium-3-carboxyl­ate hemihydrate

The asymmetric unit of the title compound, C3H4N4O2·0.5H2O, comprises two whole mol­ecules of 5-amino-1H-1,2,4-triazole-3-carb­oxy­lic acid in its zwitterionic form (proton transfer occurs from the carb­oxy­lic acid group to the N hetero­atom at position 1), plus one water mol­ecule of crystallization. The organic moieties are disposed into supra­molecular layers linked by N—H⋯O and N—H⋯N hydrogen bonds parallel to the bc plane. Additional O—H⋯O and N—H⋯O hydrogen bonds involving the water mol­ecules and the organic mol­ecules lead to the formation of double-deck supra­molecular arrangements which are inter­connected along the a axis via π–π stacking [centroid–centroid distance = 3.507 (3) Å]

Tratamiento quirúrgico de la fractura de acetábulo con luxación posterior de cadera: análisis retrospectivo de 20 casos

Entre 1985 y 1990 fueron intervenidos en nuestro servicio 20 pacientes con fractura acetabular y luxación posterior de cadera, con edades desde 22 a 53 años, 18 (90%) eran varones. Los accidentes de tráfico fueron la causa de 18 (90%) de las lesiones. Diez (50%) presentaron lesiones asociadas de importancia. Se estudió su evolución con un seguimiento medio de 5 años (rango de 3.5 a 8.1). La fractura de pared posterior ha sido la que con mayor frecuencia se ha asociado a la luxación (50%), seguida de la transversa y de pared posterior (30%). Hemos obtenido 14 (70%) resultados satisfactorios; 2 pacientes precisaron artroplastia total a los 3 años. No se observó peor evolución en los casos de mayor edad, pero sí en aquéllos que fueron intervenidos pasadas las 3 semanas del accidente. Se comentan aspectos de la evaluación preoperatoria.Between 1985 and 1990, 20 patients aged from 22 to 53 years with fracture of the acetabulum and posterior dislocation of the femoral head were treated surgically. Eighteen (90%) were male. Eighteen (90%) of the fractures were sustained in a motor-vehicle accident. Ten (50%) patients had multiple associated injuries. The average duration of the follow-up period was 5 years (range from 3.5 to 8.1). Ten (50%) of the dislocations were associated with posterior wall fracture. We observed 14 (70%) satisfactory results; 2 patients needed a THA 3 years later. Best results were achieved with early treatment. Aspects of the preoperative evaluation are commented

Tratamiento quirúrgico de la pseudoartrosis de la apófisis odontoides: Presentación de dos casos

Se presenta nuestra experiencia de dos casos de pseudoartrosis de apófisis odontoides tratadas quirúrgicamente mediante atornillado directo a compresión por vía anterior paraesternomocleidomastoidea. El resultado final fue satisfactorio en el primer caso, teniendo que realizarse una artrodesis posterior C1-C2 en el segundo. Se discute la posibilidad de un exceso de angulación posterioSe presenta nuestra experiencia de dos casos de pseudoartrosis de apófisis odontoides tratadas quirúrgicamente mediante atornillado directo a compresión por vía anterior paraesternomocleidomastoidea. El resultado final fue satisfactorio en el primer caso, teniendo que realizarse una artrodesis posterior C1-C2 en el segundo. Se discute la posibilidad de un exceso de angulación posterior en la colocación del tornillo como causa del fracaso de la técnica.en la colocación del tornillo como causa del fracaso de la técnica.Two cases of odontoid process non-union treated by direct screw compression through an anterior approach are presented. The outcome was satisfactory in one case. The other required posterior C1-C2 union because of anterior screwing failure. An excessive posterior angulation of the screw thought to be the cause of anterior fusion failure