551 research outputs found

    Roughness analysis applied to niobium thin films grown on MgO(001) surfaces for superconducting radio frequency cavity applications

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    This paper describes surface studies to address roughness issues inherent to thin film coatings deposited onto superconducting radio frequency (SRF) cavities. This is particularly relevant for multilayered thin film coatings that are being considered as a possible scheme to overcome technical issues and to surpass the fundamental limit of similar to 50 MV/m accelerating gradient achievable with bulk niobium. In 2006, a model by Gurevich [Appl. Phys. Lett. 88, 012511 (2006)] was proposed to overcome this limit that involves coating superconducting layers separated by insulating ones onto the inner walls of the cavities. Thus, we have undertaken a systematic effort to understand the dynamic evolution of the Nb surface under specific deposition thin film conditions onto an insulating surface in order to explore the feasibility of the proposed model. We examine and compare the morphology from two distinct Nb/MgO series, each with its own epitaxial registry, at very low growth rates and closely examine the dynamical scaling of the surface features during growth. Further, we apply analysis techniques such as power spectral density to the specific problem of thin film growth and roughness evolution to qualify the set of deposition conditions that lead to successful SRF coatings. DOI: 10.1103/PhysRevSTAB.16.02200

    Efecto de la música sobre la ansiedad y el dolor en pacientes con ventilación mecánica

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    La capacidad de la música para aliviar la ansiedad o el dolor ha sido utilizada ampliamente a lo largo de la historia. Objetivo: Examinar los efectos de la música sobre la ansiedad y el dolor en pacientes con ventilación mecánica invasiva. Diseño: Un ensayo aleatorizado controlado con medidas repetidas. Material y método: estudio prospectivo experimental con distribución aleatoria, en un hospital universitario de tercer nivel, de enero de 2009 a junio de 2010. La muestra fue de 44 participantes. La intervención consistió en una sesión musical de 30 min, con auriculares, en habitación individual. Al grupo control se le mantuvo sin ningún cambio en el entorno habitual de una unidad de cuidados intensivos. A cada paciente se le realizaron un mínimo de 3 y un máximo de 5 sesiones musicales. La música fue escogida por el paciente entre una selección musical preparada por el equipo investigador. La ansiedad, el dolor y las variables hemodinámicas frecuencia cardiaca, frecuencia respiratoria, tensión arterial sistólica y diastólica se midieron en el momento basal, tras la sesión musical y una hora después de la audición musical. Resultados: La musicoterapia disminuyó significativamente la ansiedad (p = 0,000), medida con la escala de Ansiedad Estado-Rasgo (STAI). No hubo diferencia significativa en los niveles de dolor (p = 0,157), medida con la escala visual analógica. No se demostró efecto sumativo a lo largo de las múltiples sesiones. Conclusión: La música reduce la ansiedad en los pacientes con ventilación mecánica invasiva, pudiéndose establecer como una herramienta no farmacológica a añadir a las opciones terapéuticas de las cuales disponemos

    Niobium thin film deposition studies on copper surfaces for superconducting radio frequency cavity applications

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    Thin film coatings have the potential to increase both the thermal efficiency and accelerating gradient in superconducting radio frequency accelerator cavities. However, before this potential can be realized, systematic studies on structure-property correlations in these thin films need to be carried out since the reduced geometry, combined with specific growth parameters, can modify the physical properties of the materials when compared to their bulk form. Here, we present our systematic studies of Nb thin films deposited onto Cu surfaces to clarify possible reasons for the limited success that this process exhibited in previous attempts. We compare these films with Nb grown on other surfaces. In particular, we study the crystal structure and surface morphology and their effect on superconducting properties, such as critical temperature and lower critical field. We found that higher deposition temperature leads to a sharper critical temperature transition, but also to increased roughness indicating that there are competing mechanisms that must be considered for further optimization

    Optical polarization and spectral properties of the H-poor superluminous supernovae SN 2021bnw and SN 2021fpl

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    New optical photometric, spectrocopic and imaging polarimetry data are combined with publicly available data to study some of the physical properties of the two H-poor superluminous supernovae (SLSN) SN 2021bnw and SN 2021fpl. For each SLSN, the best-fit parameters obtained from the magnetar model with \texttt{MOSFiT} do not depart from the range of parameter obtained on other SLSNe discussed in the literature. A spectral analysis with \texttt{SYN++} shows that SN 2021bnw is a W Type, Fast evolver, while SN 2021fpl is a 15bn Type, Slow evolver. The analysis of the polarimetry data obtained on SN 2021fpl at four epochs (+1.8, +20.6, +34.1 and +43.0 days, rest-frame) shows >3σ> 3\sigma polarization detections in the range 0.8--1 %\%. A comparison of the spectroscopy data suggests that SN 2021fpl underwent a spectral transition a bit earlier than SN 2015bn, during which, similarly, it could have underwent a polarization transition. The analysis of the polarimetry data obtained on SN 2021bnw do not show any departure from symmetry of the photosphere at an empirical diffusion timescale of \approx 2 (+81.1 days rest-frame). This result is consistent with those on the sample of W Type SLSN observed at empirical diffusion timescale \le 1 with that technique, even though it is not clear the effect of limited spectral windows varying from one object to the other. Measurements at higher empirical diffusion timescale may be needed to see any departure from symmetry as it is discussed in the literature for SN 2017egm.Comment: 29 pages, 13 Figures, 15 Tables, submitted to the MNRA

    Relevance of Environmental Surveys on the Design of a New Municipal Waste Management System on the City of Kokshetau (Kazakhstan)

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    [EN] The increasing amount of municipal solid waste is one of the most urgent problems for many countries in the world, including Kazakhstan. In 2021, a new environmental code was adopted in the country. In accordance with this code, some types of garbage (such as plastic, paper, cardboard or glass) are not accepted at sanitary landfills. Besides this, a separate collection system of municipal solid waste in Kokshetau is practically absent, and only a few points for the collection of secondary raw materials are currently available. The state bodies are faced with the task of introducing dual waste collection technology. This work shows the results obtained by a sociological online survey performed among the residents of the city in order to identify their attitudes with respect to the separation and classification of waste. This survey allowed us to study the level of environmental awareness and interest in solving waste-related issues in the population of Kokshetau. The results show that the majority of the population is concerned about the problem of municipal waste management and is ready to cooperate on the classification of waste at the original source. Additionally, it was revealed that the survey participants have weak environmental knowledge, so it is necessary to conduct environmental education activities for the population. The existence of a statistically significant relationship between the variables under consideration in terms of the Pearson Chi-squared criterion was observed.This research was funded by the Science Committee of the Ministry of Education and Science of the Republic of Kazakhstan, grant number IRN: AP09259015 included in the grant financing of scientific and scientific and technical projects for 2021-2023 with a period of implementation of 36 months. Project topic: Development of technology for the efficient processing of organic waste using the thermophilic fermentation method to produce biological fertilizers.Bayazitova, ZE.; Rodrigo-Ilarri, J.; Rodrigo-Clavero, M.; Kurmanbayeva, AS.; Safronova, NM.; Belgibayeva, AS.; Zhaparova, SB.... (2022). Relevance of Environmental Surveys on the Design of a New Municipal Waste Management System on the City of Kokshetau (Kazakhstan). Sustainability. 14(21):1-16. https://doi.org/10.3390/su142114368116142

    A fitted numerical method for singularly perturbed parabolic reaction-diffusion problems

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    This paper treats a time-dependent singularly perturbed reaction-diffusion problem. We semidiscretize the problem in time by means of the classical backward Euler method. We develop a fitted operator finite difference method (FOFDM) to solve the resulting set of linear problems (one at each time level). We prove that the underlying fitted operator satisfies the maximum principle. This result is then used in the error analysis of the FOFDM. The method is shown to be first order convergent in time and second order convergent in space, uniformly with respect to the perturbation parameter. We test the method on several numerical examples to confirm our theoretical findings.Web of Scienc

    Human Papillomavirus and factors associated with recurrence in sinonasal inverted papillomas from Poland and Spain

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    Sinonasal inverted papilloma (SNIP) is a benign but locally aggressive tumor that has a tendency for recurrence and malignant transformation. The role of human papillomavirus (HPV) in SNIP is controversial. To determine the HPV-DNA prevalence and type distribution in SNIP in two different geographic areas and assess the association between SNIP recurrence and HPV infection, as well as additional potential etiologic factors. Two retrospective cohorts of SNIP patients from Poland and Spain were evaluated. Demographic, tobacco/alcohol use, clinical, and follow-up data were collected. All samples were subject to histopathologic evaluation, DNA quality control, and HPV-DNA detection by PCR. HPV-DNA positive samples and a random sample of HPV-DNA negative cases were further subject to p16INK4a analysis. Proportional-hazards models were used to evaluate the risk of recurrence by selected variables. Seventy-nine SNIP patients (46 from Spain diagnosed between 1995 and 2014, and 33 from Poland diagnosed between 2012 and 2017) were included in the study. HPV-DNA was detected in four patients (5.1%), two from each region, and all four were positive for the HPV11 subtype. Seventeen patients (21.5%) experienced recurrence, with a median time to recurrence of 14 months. No association was identified between lesional HPV-DNA positivity, toxic habits, Krouse stage, or malignant transformation and a higher risk of recurrence. The low prevalence of HPV-DNA in SNIPs suggests that HPV is not a main etiology for development of these lesions. With a lack of association between the evaluated factors and recurrence, further research with larger number of patients and additional biomarkers is warranted to further understand predisposing risk factors

    Assessing the conservation value of waterbodies: the example of the Loire floodplain (France)

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    In recent decades, two of the main management tools used to stem biodiversity erosion have been biodiversity monitoring and the conservation of natural areas. However, socio-economic pressure means that it is not usually possible to preserve the entire landscape, and so the rational prioritisation of sites has become a crucial issue. In this context, and because floodplains are one of the most threatened ecosystems, we propose a statistical strategy for evaluating conservation value, and used it to prioritise 46 waterbodies in the Loire floodplain (France). We began by determining a synthetic conservation index of fish communities (Q) for each waterbody. This synthetic index includes a conservation status index, an origin index, a rarity index and a richness index. We divided the waterbodies into 6 clusters with distinct structures of the basic indices. One of these clusters, with high Q median value, indicated that 4 waterbodies are important for fish biodiversity conservation. Conversely, two clusters with low Q median values included 11 waterbodies where restoration is called for. The results picked out high connectivity levels and low abundance of aquatic vegetation as the two main environmental characteristics of waterbodies with high conservation value. In addition, assessing the biodiversity and conservation value of territories using our multi-index approach plus an a posteriori hierarchical classification methodology reveals two major interests: (i) a possible geographical extension and (ii) a multi-taxa adaptation

    The hyperfine properties of a hydrogenated Fe/V superlattice

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    : We study the effect of hydrogen on the electronic, magnetic and hyperfine structures of an iron-vanadium superlattice consisting of three Fe monolayers and nine V monolayers. The contact charge density ({\rho}), the contact hyperfine field (Bhf) and the electronic field gradient (EFG) at the Fe sites for different H locations and H fillings are calculated using the first principle full-potential linear-augmented-plane-wave (FP-LAPW) method . It is found that sizeable changes in the hyperfine properties are obtained only when H is in the interface region.Comment: 6 pages, 2 figures, 3 tables, ICAME 2011 conference (Kobe, Japan

    Histerectomía total laparoscópica asistida por robot: Experiencia de Clínica Indisa

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    Se comunica la experiencia y los resultados obtenidos de 110 casos de histerectomía total laparoscópica asistida por robot entre junio de 2010 y abril de 2013 en Clínica Indisa. Parámetros evaluados: diagnóstico, edad, índice de masa corporal (IMC), tiempo de instalación de trócares (TT), tiempo operatorio (TO), conversión a laparotomía, sangrado, dolor postoperatorio, estadía hospitalaria y complicaciones postoperatorias. Los diagnósticos preoperatorios más frecuentes fueron: miomatosis y adenomiosis. El promedio de edad fue de 45 años y de IMC 25,8 kg/m2, 7% de las pacientes con IMC mayor de 35. TT promedio de 14 min y TO fue de 81 min. No hubo conversión a laparotomía. Sangrado promedio de 17 ml. A las 48 horas pos intervención el 100% de las pacientes presentó un test de EVA de 0-2. Promedio de estadía hospitalaria fue 1,6 días. Hubo tres complicaciones postoperatorias: una neumonía, un desgarro vulvar y una dehiscencia de la cúpula vaginal. Conclusión: La histerectomía total laparoscópica asistida por robot es una técnica segura y ofrece ventajas al paciente y cirujano
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