1,797 research outputs found

    The outcome of competitive equilibrium rules in buyer-seller markets when the agents play strategically

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    Financial support from the Ministerio de Ciencia y Tecnología (ECO2015-63679-P), Generalitat de Catalunya (2014SGR-142), the Severo Ochoa Programme for Centres of Excellence in R&D (SEV-2015-0563) and ICREA Academia.We analyze the two-stage games induced by competitive equilibrium rules for the buyer-seller market of Shapley and Shubik (Int J Game Theory 1:111-130, 1972). In these procedures, first sellers and then buyers report their valuation and the outcome is determined by a competitive equilibrium outcome for the market reported by the agents. We provide results concerning buyers and sellers' equilibrium strategies. In particular, our results point out that, by playing first, sellers are able to instigate an outcome that corresponds to the sellers' optimal competitive equilibrium allocation for the true market

    Primary gas thermometry by means of laser-absorption spectroscopy: Determination of the Boltzmann constant

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    We report on a new optical implementation of primary gas thermometry based on laser absorption spectrometry in the near infrared. The method consists in retrieving the Doppler broadening from highly accurate observations of the line shape of the R(12) ν1+2ν210+ν3\nu_{1} + 2 \nu_{2}^{\phantom{1}0} + \nu_{3} transition in CO2_{2} gas at thermodynamic equilibrium. Doppler width measurements as a function of gas temperature, ranging between the triple point of water and the gallium melting point, allowed for a spectroscopic determination of the Boltzmann constant with a relative accuracy of 1.6×104\sim1.6\times10^{-4}.Comment: Submitted to Physical Review Letter

    Observing the intrinsic linewidth of a quantum-cascade laser: beyond the Schawlow-Townes limit

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    A comprehensive investigation of the frequency-noise spectral density of a free-running mid-infrared quantum-cascade laser is presented for the first time. It provides direct evidence of the leveling of this noise down to a white noise plateau, corresponding to an intrinsic linewidth of a few hundred Hz. The experiment is in agreement with the most recent theory on the fundamental mechanism of line broadening in quantum-cascade lasers, which provides a new insight into the Schawlow-Townes formula and predicts a narrowing beyond the limit set by the radiative lifetime of the upper level.Comment: 4 pages, 4 figure

    Protein kinase C epsilon is required for macrophage activation and defense against bacterial infection

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    Imperial Cancer Research Fund, and grants FEDER 2FD-1997-1432 from Comisión Interministerial de Ciencia y Tecnología (CICYT) and PM98-0120 from Dirección General de Enseñanza Superior e Investigación Científica, Spain. F. Otto was supported by Deutsche Forschungsgemeinschaft grant Ot 134/1-1

    Evaluation of the small ruminants cystic ovarian disease using transrectal ultrasonography

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    A transrectal ultrasonic method using a 7.5 MHz linear-array transducer was used in 194 ewes and 39 goats to study the characteristc of cystic ovaries. Cystic structures found on the ovaries include follicular cysts and luteinised cysts. Follicular cysts showed up as non-echogenic structures with a 1.5 ± 0.4 cm diameter. The cysts luteinised showed an echogenic rim of tissue, ranging from 2- 3 mm, around the cyst; the central cavity was 1±0.2 cm. In total, 4.1 percent of ewes and 5.1 percent of goats exhibited follicular cysts. Only 1 percent of ewes and 2.6 percent of goats showed luteinised cysts. In conclusion, the results demonstrated that transrectal ultrasonography provides a noninvasive form of visual access to the ovary from small ruminants, to evaluate pathological changes before the aplication of superovulation treatments and embryo transfer.Se ha realizado un estudio de las características ecográficas de estructuras quísticas ováricas en 194 ovejas y 39 cabras de diferentes razas y procedentes de distintas zonas geográficas, con el objeto de valorar la ecografía transrectal con sondas de alta resolución (7,5 MHz) como criterio de selección de animales destinados a programas de superovulación y recogida de embriones. Los quistes foliculares tenían una incidencia de presentación del 4,1 p.100 en las ovejas y del 5,1 p.100 en las cabras, presentándose ecográficamente con una morfología esférica anecoica de 1,5±0,4 cm de diámetro, con paredes finas y generalmente bien definidas. Los quistes luteínicos tuvieron una presentación del 1 p.100 en las ovejas y del 2,6 p.100 en las cabras. Ecográficamente se caracterizaban por presentar una cavidad central anecógena 1±0,2 cm, rodeada por un anillo ecogénico de 2-3 mm de espesor. No había diferencias significativas en la frecuencia de presentación de quistes ováricos entre ambas especies. Los resultados muestran que la ecografía transrectal con sondas de alta resolución permite la realización de un diagnóstico eficaz de la patología quística ovárica en los pequeños rumiantes, siendo recomendable esta metodología en la selección de hembras donantes y receptoras

    Septic arthritis of the knee due to Prevotella loescheii following tooth extraction

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    This is a case report of septic arthritis of the knee due to Prevotella loescheii, in a patient with advanced arthrosis. Two weeks beforehand he had undergone a dental root extraction without antibiotic prophylaxis. His knee had become inflamed 48 hours after extraction and he was started on ibuprofen and steroid treatment (prescribed by his primary health care doctor). With a provisional diagnosis of septic arthritis, synovial fluid was taken for study. Antimicrobial therapy was commenced with amoxicillin/clavulanic acid and the patient progressed satisfactorily. Prevotella loescheii was identified by anaerobic culture. A site of origin for the infection was never found. Joint infection is generally secondary to haematogenous dissemination of bacteria from habitual sites such as odontogenic locations. We suggest that patients with inflammatory arthropathies should be considered as candidates for antibiotic prophylaxis in oral surgery and invasive dental procedures. We suggest, in these cases, the use of antibiotic with spectrum against aerobic and anaerobic bacteria

    Luxación traumática de la rodilla

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    La luxación traumática de la rodilla es la lesión poco frecuente que se asocia a grandes lesiones cápsuloligamentosas y que a menudo afecta a estructuras neurológicas y vasculares. La lesión vascular es la complicación más importante. Todos los autores coinciden en que el diagnóstico precoz y tratamiento urgente de las lesiones de la arteria poplítea son esenciales. Sin embargo, no existe el mismo acuerdo en cuanto al tratamiento de las lesiones cápsuloligamentosas. Algunos autores publican buenos resultados con tratamientos no quirúrgicos, aunque otros consideran que el mejor tratamiento es la reparación completa de las lesiones ligamentosas. Hemos tratado en nuestro hospital siete casos de luxación traumática de rodilla en los últimos 20 años. Presentamos el tratamiento realizado, sus complicaciones y resultados.Traumatic knee dislocation is an uncommon injury associated with extensive soft tissue damage and often neurovascular involvement. Vascular injury is the most serious complication. There is genera agreement that early diagnosis and immediate treatment of popliteal artery disruption is essential. However there is no consensus about treatment of capsular and ligamentous injuries. Some authors reported good results advocated the repair of all ligaments in the best method. Seven traumatic knee dislocations have been treated in our hospital for last 20 years. Initial treatment, complications and results are presented

    Self-trapping in B-doped amorphous Si: Intrinsic origin of low acceptor efficiency

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    We have used ab initio simulations to study the doping efficiency of amorphous semiconductors, in particular of B-doped amorphous Si. We have found that even in the optimum case of substitutional doping in dangling-bond free amorphous Si the holes provided by B atoms do not behave as free carriers. Instead, they are trapped into regions with locally distorted bond angles. Thus, the effective activation energy for hole conduction turns to be the hole binding energy to these traps. In the case of high B concentration, the trap states move deeper in the gap and the binding energy and spatial localization of holes increase. In addition, B atoms have lower energies for shorter bond lengths, configurations favored in the vicinity of these traps
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