854 research outputs found

    Inverse diffraction for the Atmospheric Imaging Assembly in the Solar Dynamics Observatory

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    The Atmospheric Imaging Assembly in the Solar Dynamics Observatory provides full Sun images every 1 seconds in each of 7 Extreme Ultraviolet passbands. However, for a significant amount of these images, saturation affects their most intense core, preventing scientists from a full exploitation of their physical meaning. In this paper we describe a mathematical and automatic procedure for the recovery of information in the primary saturation region based on a correlation/inversion analysis of the diffraction pattern associated to the telescope observations. Further, we suggest an interpolation-based method for determining the image background that allows the recovery of information also in the region of secondary saturation (blooming)

    Aortopexy for the treatment of tracheomalacia in children: review of the literature

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    ABSTRACT: Severe tracheomalacia presents a significant challenge for Paediatricians, Intensivists, Respiratory Physicians, Otolaryngologists and Paediatric Surgeons. The treatment of tracheomacia remains controversial, but aortopexy is considered by most to be one of the best options. We conducted a review of the English literature relating to aortopexy. Among 125 papers, 40 have been included in this review. Among 758 patients (62% males) affected with tracheomalacia, 581 underwent aortopexy. Associated co-morbidities were reported in 659 patients. The most frequent association was with oesophageal atresia (44%), vascular ring or large vessel anomalies (18%) and innominate artery compression (16%); in 9% tracheomalacia was idiopathic. The symptoms reported were various, but the most important indication for aortopexy was an acute life-threatening event (ALTE), observed in 43% of patients. The main preoperative investigation was bronchoscopy. Surgical approach was through a left anterior thoracotomy in 72% of patients, while median approach was chosen in 14% and in 1.3% a thoracoscopic aortopexy was performed. At follow-up (median 47 months) more than 80% of the patients improved significantly, but 8% showed no improvement, 4% had a worsening of their symptoms and 6% died. Complications were observed in 15% of patients, in 1% a redo aortopexy was deemed necessary. In our review, we found a lack of general consensus about symptom description and evaluation, indications for surgery, though ALTE and bronchoscopy were considered by all an absolute indication to aortopexy and the gold standard for the diagnosis of tracheomalacia, respectively. Differences were reported also in surgical approaches and technical details, so that the same term “aortopexy” was used to describe different types of procedures. Whatever approach or technique was used, the efficacy of aortopexy was reported as high in the majority of cases (more than 80%). A subgroup of patients particularly delicate is represented by those with associated gastro-esophageal reflux, in whom a fundoplication should be performed. Other treatments of tracheomalacia, particularly tracheal stenting, were associated with a higher rate of failure, severe morbidity and mortality. NON ENGLISH ABSTRACT: La tracheomalacia severa rappresenta una sfida per Pediatri, Intensivisti, Pneumologi, Otorinolaringoiatri, Chirurghi Pediatri. Il trattamento della tracheomalacia è tuttora controverso. L’aortopessi è considerata da molti la migliore opzione terapeutica. Abbiamo condotto una revisione della letteratura di lingua inglese su tale argomento. Di 125 lavori, 40 sono stati inclusi nella revisione. Tra 758 pazienti (62% maschi) affetti da tracheomalacia, 581 sono stati sottoposti ad aortopessi tra il 1968 e il 2008. In 659 pazienti alcune comorbidità erano presenti. L’associazione più frequente era con l’atresia esofagea (44%), l’anello vascolare o un’anomalia dei grossi vasi (18%), la compressione da parte dell’arteria innominata (16%); nel 9% la tracheomalacia era idiopatica. I sintomi riportati sono stati variabili, ma l’indicazione più importante all’aortopessi sono stati eventi di ALTE, osservati nel 43% dei pazienti. Lo studio diagnostico preoperatorio principale è stato la broncoscopia. L’approccio chirurgico è avvenuto attraverso una toracotomia anteriore sinistra nel 72% dei pazienti, mentre un approccio mediano è stato scelto nel 14% e nell’1.3% dei casi è stato eseguito un approccio toracoscopico. Al follow-up (mediana di 47 mesi) la maggioranza dei pazienti sono migliorati significativamente, ma l’8% di essi non è migliorato, il 4% è peggiorato e il 6% è morto. Complicazioni sono state riportate nel 15% dei pazienti, nell’1% un nuovo intervento di aortopessi è stato necessario. In questa revisione abbiamo trovato che non c’è un consenso generale sulla valutazione e sulla descrizione dei sintomi, sulle indicazioni chirurgiche ed esami preoperatori, anche se le ALTE e la broncoscopia venivano considerate rispettivamente un’indicazione assoluta all’aortopessi e il “gold standard” diagnostico per la tracheomalacia. Venivano riportate differenze negli approcci chirurgici e nei dettagli tecnici, e lo stesso termine di aortopessi veniva usato per indicare diverse procedure chirurgiche. In ogni caso, indipendentemente dall’approccio o tecnica utilizzati, l’efficacia dell’aortopessi veniva riportata come elevata nella maggioranza dei casi (più dell’80%). Un sottogruppo di pazienti particolarmente delicato è rappresentato da quelli con reflusso gastroesofageo associato, nei quali sarebbe indicata una fundoplicatio. Altri trattamenti della tracheomalacia, quali stent tracheale, sembrano gravati da una maggiore percentuale di insuccessi, morbidità severa e mortalità

    What is the gamma gamma resonance at 750 GeV?

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    Run 2 LHC data show hints of a new resonance in the diphoton distribution at an invariant mass of 750 GeV. We analyse the data in terms of a new boson, extracting information on its properties and exploring theoretical interpretations. Scenarios covered include a narrow resonance and, as preliminary indications suggest, a wider resonance. If the width indications persist, the new particle is likely to belong to a strongly-interacting sector. We also show how compatibility between Run 1 and Run 2 data is improved by postulating the existence of an additional heavy particle, whose decays are possibly related to dark matter.Comment: v2: 45 pages, 12 figures, final. Factor of 2 changed in table 1, 4th ro

    Properties of the Acceleration Regions in Several Loop-structured Solar Flares

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    Using {\em RHESSI} hard X-ray imaging spectroscopy observations, we analyze electron flux maps for a number of extended coronal loop flares. For each event, we fit a collisional model with an extended acceleration region to the observed variation of loop length with electron energy EE, resulting in estimates of the plasma density in, and longitudinal extent of, the acceleration region. These quantities in turn allow inference of the number of particles within the acceleration region and hence the filling factor ff -- the ratio of the emitting volume to the volume that encompasses the emitting region(s). We obtain values of ff that lie mostly between 0.1 and 1.0; the (geometric) mean value is f=0.20×÷3.9f = 0.20 \times \div 3.9, somewhat less than, but nevertheless consistent with, unity. Further, coupling information on the number of particles in the acceleration region with information on the total rate of acceleration of particles above a certain reference energy (obtained from spatially-integrated hard X-ray data) also allows inference of the specific acceleration rate (electron s1^{-1} per ambient electron above the chosen reference energy). We obtain a (geometric) mean value of the specific acceleration rate η(20\eta(20 keV) =(6.0×/÷3.4)×103 = (6.0 \times / \div 3.4) \times 10^{-3} electrons s1^{-1} per ambient electron; this value has implications both for the global electrodynamics associated with replenishment of the acceleration region and for the nature of the particle acceleration process

    Adaptation of a culturally relevant nutrition and physical activity program for low-income, Mexican-origin parents with young children.

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    Latino children experience higher rates of obesity than do non-Latino white children. Family-centered nutrition interventions can slow the rate of weight gain in this population. Niños Sanos, Familia Sana (Healthy Children, Healthy Family) is a 5-year, community-based, participatory research study that targets rural Mexican-origin farmworker families with children aged 2 to 8 years in California's Central Valley. Adaptation of a culturally relevant obesity prevention program involved qualitative research to tailor key obesity prevention messages, pilot testing and implementation of key messages and activities at family nights, and continual modification to incorporate culturally innovative elements. Of the 238 families enrolled, 53% (125) attended the recommended minimum of 5 (of 10 possible) classes during the first year. A university and community partnership can guide development of a culturally tailored obesity prevention program that is suitable for reaching a high-risk Mexican-origin audience through cooperative extension and other public health programs

    The crustal structure of Carnegie Ridge inferred from gravity and seismic data

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    Carnegie Ridge is a prominent bathymetric feature of the Gal??pagos Volcanic Province originated from the interaction of the Gal??pagos Hot Spot and the Cocos - Nazca Spreading Center. Our present knowledge regarding its crustal structure is limited to ridge transects along which wide-angle refraction seismic experiments have been conducted. In this study, the long-wavelength crustal structure of Carnegie Ridge between ~81?? W and 89?? W was determined by employing 2-D forward gravity modeling as the primary analytical technique. Model structures were built by assuming Airy isostasy and crustal layers of constant density. The geometry and density structure of the thickened oceanic crust beneath the ridge was constrained based on available seismic velocity models. Except for regions near the Ecuador Trench, the gravity modeling solution along the different transects examined in this study accounted adequately for the observed gravity anomaly field over the ridge. Crustal overthickening mainly accommodated in oceanic layer 3 and the asymmetry of the crustal root geometry characterize the estimated long-wavelength crustal structure. The asymmetry on eastern Carnegie Ridge is thought to be related to a ridge-related rifting whereas the origin and nature of that estimated on western Carnegie Ridge remain uncertain. Crustal volume fluxes were calculated at Carnegie Ridge and the Gal??pagos Archipelago, and at Cocos Ridge in order to explain the along-axis variations of the estimated crustal thickness. Along-axis crustal thickness variations on eastern Carnegie Ridge, and the formation of its bathymetric saddle were found to be related to the decline in the total volume output of the Gal??pagos Hot Spot. According to my results, this decay started soon after the spreading center shifted to the south of the hotspot (i.e., ~15 Ma) and continued for ~4.5 m.y. Since ~10 Ma the volume output of the GHS started to increase again, giving rise to the formation of western Carnegie Ridge and the Gal??pagos Archipelago. This increase continued until ~2 Ma, when the hotspot intensity started a new decrease that continues until the present time

    Uso del videomarketing en tiempos de la Covid-19: estrategias del sector de la moda

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    La consolidación de plataformas con capacidad para desarrollo de contenidos de video ha impulsado de manera significativa la manera cómo las marcas de moda trabajan sus estrategias de comunicación. Este artículo tiene el objetivo de profundizar en el conocimiento de las estrategias de contenido digital desarrollado por las marcas de moda, buscando identificar tres aspectos principales: las plataformas digitales más populares donde las marcas emplean videomarketing, según la categoría de su posicionamiento; qué diferencias existen en tipologías de videos y mensajes; y qué tendencias de contenidos de videos han surgido durante la pandemia de la Covid19. Para esta finalidad, este estudio emplea un análisis de contenido aplicado a las redes sociales de cuatro marcas de moda posicionadas en las categorías de lujo y de moda accesible durante el periodo de confinamiento provocado por la pandemia de la Covid19. El artículo pone en evidencia que los contenidos de marca en formato de vídeo son menos utilizados en comparación con los formatos de texto e imágenes publicados en plataformas online, y discute las principales diferencias en las técnicas de videomarketing utilizadas y las más importantes innovaciones en las respuestas de las marcas

    Calculative practices, social movements and the rise of collective identity: how #istayathome mobilised a nation

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    Purpose – The Italian government addressed the first wave of its COVID-19 outbreak with a series of social restrictions and calculative practices, all branded with the slogan #istayathome. The hashtag quickly went viral, becoming both a mandate and a mantra and, as the crisis played out, we witnessed the rise of the Italian social movement #istayathome. This study examines how the government’s calculative practices led to #istayathome and the constituents that shaped this social movement. Design/methodology/approach – The authors embrace social movement theory and the collective identity perspective to examine #istayathome as a collective action and social movement. Using passive netnography, text mining and interpretative text analysis enhanced by machine learning, the authors analysed just over 350,000 tweets made during the period March to May 2020, each brandishing the hashtag #istayathome. Findings – The #istayathome movement gained traction as a response to the Italian government’s call for collective action. Thus, people became an active part of mobilising collective responsibility, enhancing the government’s plans. A collective identity on the part of the Italian people sustained the mass mobilisation, driven by cohesion, solidarity and a deep cultural trauma from COVID-19’s dramatic effects. Popular culture and Italy’s long traditions also helped to form the collective identity of #istayathome. This study found that calculative practices acted as a persuasive technology in forming this collective identity and mobilising people’s collective action. Numbers stimulated the cognitive, moral and emotional connections of the social ties shaping collective identity and responsibility. Thus, through collective identity, calculative practices indirectly influenced mass social behaviors and the social movement. Originality/value – This study offers a novel theoretical perspective and empirical knowledge to explain how government power affects people’s culture and everyday life. It unveils the sociological drivers that mobilise collective behaviors and enriches the accounting literature on the effects of calculative practices in managing emergencies. The study contributes to theory by providing an understanding of how calculative practices can influence collective behaviors and can be used to construct informal networks that go beyond the government’s traditional formalities
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