22 research outputs found

    The ALICE experiment at the CERN LHC

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    ALICE (A Large Ion Collider Experiment) is a general-purpose, heavy-ion detector at the CERN LHC which focuses on QCD, the strong-interaction sector of the Standard Model. It is designed to address the physics of strongly interacting matter and the quark-gluon plasma at extreme values of energy density and temperature in nucleus-nucleus collisions. Besides running with Pb ions, the physics programme includes collisions with lighter ions, lower energy running and dedicated proton-nucleus runs. ALICE will also take data with proton beams at the top LHC energy to collect reference data for the heavy-ion programme and to address several QCD topics for which ALICE is complementary to the other LHC detectors. The ALICE detector has been built by a collaboration including currently over 1000 physicists and engineers from 105 Institutes in 30 countries. Its overall dimensions are 161626 m3 with a total weight of approximately 10 000 t. The experiment consists of 18 different detector systems each with its own specific technology choice and design constraints, driven both by the physics requirements and the experimental conditions expected at LHC. The most stringent design constraint is to cope with the extreme particle multiplicity anticipated in central Pb-Pb collisions. The different subsystems were optimized to provide high-momentum resolution as well as excellent Particle Identification (PID) over a broad range in momentum, up to the highest multiplicities predicted for LHC. This will allow for comprehensive studies of hadrons, electrons, muons, and photons produced in the collision of heavy nuclei. Most detector systems are scheduled to be installed and ready for data taking by mid-2008 when the LHC is scheduled to start operation, with the exception of parts of the Photon Spectrometer (PHOS), Transition Radiation Detector (TRD) and Electro Magnetic Calorimeter (EMCal). These detectors will be completed for the high-luminosity ion run expected in 2010. This paper describes in detail the detector components as installed for the first data taking in the summer of 2008

    Seed germination and emergence of Eragrostis tenuifolia (A. Rich.) Hochst. ex Steud. in response to environmental factors

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    Eragrostis tenuifolia is a weed species that is gaining ground in Brazil. This weed occurs in pastures, grasslands, crop fields, and roadsides. The objective of this study was to examine the effects of different environmental factors on E. tenuifolia seed germination and seedling emergence. The optimum constant temperature for germination was around 35–30°C. It was also found that 85% of seeds germinated under a 30/20°C alternate temperature regime. Light appears to have a positive effect on seed germination. No seedlings emerged when seeds were buried 3 cm or deeper. The results suggested that E. tenuifolia has the potential to spread into pastures and in no-tillage crop systems in Brazil. Measures such as the use of cover crops and/or soil cultivation can be used to limit germination and seedling emergence, respectively

    Participación de enfermeros(as) de la Región de las Américas en una capacitación virtual sobre liderazgo

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    Objective: To analyze the participation of nurses from the Region of the Americas in a nursing leadership development initiative which uses a self-learning virtual training. Method: This is a descriptive and quantitative study with qualitative descriptions on data obtained from the Virtual Campus for Public Health PAHO/WHO (VCPH) with the VCPH quality survey - self-learning courses of the Virtual Training of Nursing Leadership: empowerment of nurse leaders in Latin-America. Descriptive statistics were calculated. Results: 3348 nurses participated in this course from august 2015 to july 2018. The nurses from Ecuador, Mexico, and Colombia represented 83.1% of the total participation. Only 8.7% reported having a leadership position specifically. The course was found useful among those persons with barriers related to the access to a permanent education. Discussion: The larger participation in some countries could be the result of the broader diffusion and access to virtual platforms. The advantages of using a virtual environment include the possibility to further strengthen the training of health human resources, particularly of those with physical barriers related to the development of professional skills. Conclusions: The training in a virtual environment strengthened the practice skills of the professionals enrolled in the course. Further education programs can take advantage of this kind of platforms to better prepare the future nursing leaders.Objetivo: Analisar a participação dos enfermeiros(as) da Região das Américas na iniciativa de desenvolver a liderança de enfermagem na Região, através de um curso virtual de autoaprendizagem. Método: Estudo descritivo, quantitativo com descrições qualitativas de dados obtidos do Campus Virtual de Saúde Pública da OPS/OMS por meio da Enquete de qualidade do CVSP - cursos de autoaprendizagem do Curso Virtual de Liderança em Enfermagem: Empoderamento dos(as) enfermeiros(as) líderes na América Latina. Calcularam-se medidas de estatística descritiva. Resultados: Participaram neste curso de agosto de 2015 a julho de 2018, três mil 348 enfermeiros. Do total, o Equador, o México e a Colômbia representam juntos o 83.1% da participação. Somente, 8.7% dos participantes no curso reportaram especificamente que têm cargos de liderança. O curso foi útil para as pessoas que têm barreiras relacionadas com o acesso à educação permanente. Discussão: A maior participação em alguns países pode se dever a maior difusão destes cursos ou do acesso à plataforma virtual. O entorno virtual tem benefícios e pode colaborar com o treinamento do recurso humano em saúde, já que muitos deles têm barreiras físicas para desenvolver suas habilidades profissionais. Conclusões: O entorno virtual colaborou, de forma significativa na prática destes profissionais. Aliás, foi uma iniciativa de fortalecimento da enfermagem com enfoque na formação de líderes e pode ser aproveitado para a formulação de futuros programas de educação.Objetivo: Analizar la participación de los enfermeros(as) de la Región de las Américas en la iniciativa de desarrollar el liderazgo de enfermería en la Región, a través de un curso virtual de autoaprendizaje. Método: Estudio descriptivo, cuantitativo con descripciones cualitativas de datos obtenidos del Campus Virtual de Salud Pública de la OPS/OMS por medio de la Encuesta de calidad del CVSP - cursos de autoaprendizaje del Curso Virtual de Liderazgo en Enfermería: Empoderamiento de los (las) enfermeros(as) líderes en Latinoamérica. Se calcularon medidas de estadística descriptiva. Resultados: Participaron en este curso de agosto de 2015 a julio del 2018, tres mil 348 enfermeros. Del total, Ecuador, México y Colombia representan juntos el 83.1% de la participación. Solamente, 8.7% de los participantes en el curso reportaron específicamente que tienen cargos de liderazgo. El curso fue útil para las personas que tienen barreras relacionadas con el acceso a la educación permanente. Discusión: La mayor participación en algunos países puede deberse a mayor difusión de estos cursos o del acceso a la plataforma virtual. El entorno virtual tiene beneficios y puede colaborar con el entrenamiento del recurso humano en salud, ya que muchos de ellos tienen barreras físicas para desarrollar sus habilidades profesionales. Conclusiones: El entorno virtual colaboró, de forma significativa en la práctica de estos profesionales. Además, fue una iniciativa de fortalecimiento de la enfermería con enfoque en la formación de líderes y puede ser aprovechado para la formulación de futuros programas de educación

    The design strain sensitivity of the schenberg spherical resonant antenna for gravitational waves

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    Abstract The main purpose of this study is to review the Schenberg resonant antenna transfer function and to recalculate the antenna design strain sensitivity for gravitational waves. We consider the spherical antenna with six transducers in the semi dodecahedral configuration. When coupled to the antenna, the transducer-sphere system will work as a mass-spring system with three masses. The first one is the antenna effective mass for each quadrupole mode, the second one is the mass of the mechanical structure of the transducer first mechanical mode and the third one is the effective mass of the transducer membrane that makes one of the transducer microwave cavity walls. All the calculations are done for the degenerate (all the sphere quadrupole mode frequencies equal) and non-degenerate sphere cases. We have come to the conclusion that the “ultimate” sensitivity of an advanced version of Schenberg antenna (aSchenberg) is around the standard quantum limit (although the parametric transducers used could, in principle, surpass this limit). However, this sensitivity, in the frequency range where Schenberg operates, has already been achieved by the two aLIGOs in the O3 run, therefore, the only reasonable justification for remounting the Schenberg antenna and trying to place it in the sensitivity of the standard quantum limit would be to detect gravitational waves with another physical principle, different from the one used by laser interferometers. This other physical principle would be the absorption of the gravitational wave energy by a resonant mass like Schenberg

    Status report of the Schenberg gravitational wave antenna

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    Here we present a status report of the Schenberg antenna. In the past three years it has gone to a radical upgrading operation, in which we have been installing a 1K pot dilution refrigerator, cabling and amplifiers for nine transducer circuits, designing a new suspension and vibration isolation system for the microstrip antennas, and developing a full set of new transducers, microstrip antennas, and oscillators. We are also studying an innovative approach, which could transform Schenberg into a broadband gravitational wave detector
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