116 research outputs found

    Geometric phase effects for wavepacket revivals

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    The study of wavepacket revivals is extended to the case of Hamiltonians which are made time-dependent through the adiabatic cycling of some parameters. It is shown that the quantal geometric phase (Berry's phase) causes the revived packet to be displaced along the classical trajectory, by an amount equal to the classical geometric phase (Hannay's angle), in one degree of freedom. A physical example illustrating this effect in three degrees of freedom is mentioned.Comment: Revtex, 11 pages, no figures

    Defining Substance Use Disorders: Do We Really Need More Than Heavy Use?

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    Aims: The aim of the study was to explore whether the concept of heavy substance use over time can be used as definition of substance use disorder. Methods: Narrative review. Results: Heavy use over time clearly underlies the neurobiological changes associated with current thinking of substance use disorders. In addition, there is evidence that heavy use over time can explain the majority of social problems and of burden of disease (morbidity and mortality). A definition of substance use disorders via heavy use over time would avoid some of the problems of current conceptualizations, for instance the cultural specificity of concepts such as loss of control. Finally, stressing the continuum of use may avoid the high level of stigmatization currently associated with substance use disorders. Conclusion: ‘Heavy substance use over time' seems to be a definition of substance use disorders in line with results of basic research and epidemiology. Additionally, it reduces stigmatization. This approach should thus be further explore

    Recorriendo las tramas institucionales del cuidado: Investigación colaborativa en torno al cuerpo y el cuidado

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    Este proyecto representa una profundización en la línea investigativa en torno al cuidado y el cuerpo. Esta vez dirigiendo la mirada hacia las tramas institucionales, viendo cómo se tejen los descuidos, así como el gran potencial de los espacios, propuestas y políticas de cuidado. Es una apuesta a seguir investigando de modo colaborativo, participativo y cuidadoso, en la que quienes sostenemos los procesos investigativos somos parte de la escena en cuestión. Trabajamos inicialmente con el Consejo Provincial del Niño, el Adolescente y la Familia (Copnaf), con trabajadores de tres residencias socio educativas. Más allá de los desafíos que esto implicaba, el atravesamiento innegable de la pandemia COVID-19 nos obligó a repensar acciones y localizaciones. Presentamos lo investigado junto a esos trabajadores y las dificultades en dicho proceso, así como lo investigado en las tramas institucionales del propio equipo universitario. También mantuvimos un espacio de investigación abierto en la Facultad de Trabajo Social de la Universidad Nacional de Entre Ríos (UNER), primero presencial y luego virtual. En este recorrido aparecieron varios tópicos respecto al cómo y a los modos del cuidado, lo que nos llevó a recorrer dimensiones como el amor-amorosidad, la disponibilidad afectiva, la tensegridad de la trama, los gestos y rituales, así como el poder reconocer en el propio espacio de investigación la posibilidad de explorar formas de cuidado. ARK/CAICYT: http://id.caicyt.gov.ar/ark:/s22504559/k2khuf4a

    The Tangible Common Denominator of Substance Use Disorders: A Reply to Commentaries to Rehm et al. (2013a)

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    In response to our suggestion to define substance use disorders via ‘heavy use over time', theoretical and conceptual issues, measurement problems and implications for stigma and clinical practice were raised. With respect to theoretical and conceptual issues, no other criterion has been shown, which would improve the definition. Moreover, heavy use over time is shown to be highly correlated with number of criteria in current DSM-5. Measurement of heavy use over time is simple and while there will be some underestimation or misrepresentation of actual levels in clinical practice, this is not different from the status quo and measurement of current criteria. As regards to stigma, research has shown that a truly dimensional concept can help reduce stigma. In conclusion, ‘heavy use over time' as a tangible common denominator should be seriously considered as definition for substance use disorde

    The tangible common denominator of substance use disorders: a reply to commentaries to Rehm et al. (2013a).

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    In response to our suggestion to define substance use disorders via 'heavy use over time', theoretical and conceptual issues, measurement problems and implications for stigma and clinical practice were raised. With respect to theoretical and conceptual issues, no other criterion has been shown, which would improve the definition. Moreover, heavy use over time is shown to be highly correlated with number of criteria in current DSM-5. Measurement of heavy use over time is simple and while there will be some underestimation or misrepresentation of actual levels in clinical practice, this is not different from the status quo and measurement of current criteria. As regards to stigma, research has shown that a truly dimensional concept can help reduce stigma. In conclusion, 'heavy use over time' as a tangible common denominator should be seriously considered as definition for substance use disorder

    The Pioneer Anomaly

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    Radio-metric Doppler tracking data received from the Pioneer 10 and 11 spacecraft from heliocentric distances of 20-70 AU has consistently indicated the presence of a small, anomalous, blue-shifted frequency drift uniformly changing with a rate of ~6 x 10^{-9} Hz/s. Ultimately, the drift was interpreted as a constant sunward deceleration of each particular spacecraft at the level of a_P = (8.74 +/- 1.33) x 10^{-10} m/s^2. This apparent violation of the Newton's gravitational inverse-square law has become known as the Pioneer anomaly; the nature of this anomaly remains unexplained. In this review, we summarize the current knowledge of the physical properties of the anomaly and the conditions that led to its detection and characterization. We review various mechanisms proposed to explain the anomaly and discuss the current state of efforts to determine its nature. A comprehensive new investigation of the anomalous behavior of the two Pioneers has begun recently. The new efforts rely on the much-extended set of radio-metric Doppler data for both spacecraft in conjunction with the newly available complete record of their telemetry files and a large archive of original project documentation. As the new study is yet to report its findings, this review provides the necessary background for the new results to appear in the near future. In particular, we provide a significant amount of information on the design, operations and behavior of the two Pioneers during their entire missions, including descriptions of various data formats and techniques used for their navigation and radio-science data analysis. As most of this information was recovered relatively recently, it was not used in the previous studies of the Pioneer anomaly, but it is critical for the new investigation.Comment: 165 pages, 40 figures, 16 tables; accepted for publication in Living Reviews in Relativit

    Surgical techniques for the treatment of ankyloglossia in children: a case series

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    This paper reports a series of clinical cases of ankyloglossia in children, which were approached by different techniques: frenotomy and frenectomy with the use of one hemostat, two hemostats, a groove director or laser. Information on the indications, contraindications, advantages and disadvantages of the techniques was also presented. Children diagnosed with ankyloglossia were subjected to different surgical procedures. The choice of the techniques was based on the age of the patient, length of the frenulum and availability of the instruments and equipment. All the techniques presented are successful for the treatment of ankyloglossia and require a skilled professional. Laser may be considered a simple and safe alternative for children while reducing the amount of local anesthetics needed, the bleeding and the chances of infection, swelling and discomfort

    Quantum Physics Exploring Gravity in the Outer Solar System: The Sagas Project

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    We summarise the scientific and technological aspects of the SAGAS (Search for Anomalous Gravitation using Atomic Sensors) project, submitted to ESA in June 2007 in response to the Cosmic Vision 2015-2025 call for proposals. The proposed mission aims at flying highly sensitive atomic sensors (optical clock, cold atom accelerometer, optical link) on a Solar System escape trajectory in the 2020 to 2030 time-frame. SAGAS has numerous science objectives in fundamental physics and Solar System science, for example numerous tests of general relativity and the exploration of the Kuiper belt. The combination of highly sensitive atomic sensors and of the laser link well adapted for large distances will allow measurements with unprecedented accuracy and on scales never reached before. We present the proposed mission in some detail, with particular emphasis on the science goals and associated measurements.Comment: 39 pages. Submitted in abridged version to Experimental Astronom

    Laser cooling with a modified optical shaker

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