479 resultados para 1118
Resumo:
We present Roche tomograms of the G5-G8 IV/V secondary star in the long-period cataclysmic variable BV Cen reconstructed from Magellan Inamori Kyocera Echelle spectrograph echelle data taken on the Magellan Clay 6.5-m telescope. The tomograms show the presence of a number of large, cool star-spots on BV Cen for the first time. In particular, we find a large high-latitude spot which is deflected from the rotational axis in the same direction as seen on the K3-K5 IV/V secondary star in the cataclysmic variable AE Aqr. BV Cen also shows a similar relative paucity of spots at latitudes between 40° and 50° when compared with AE Aqr. Furthermore, we find evidence for an increased spot coverage around longitudes facing the white dwarf which supports models invoking star-spots at the L1 point to explain the low states observed in some cataclysmic variables. In total, we estimate that some 25 per cent of the Northern hemisphere of BV Cen is spotted. We also find evidence for a faint, narrow, transient emission line with characteristics reminiscent of the peculiar low-velocity emission features observed in some outbursting dwarf novae. We interpret this feature as a slingshot prominence from the secondary star and derive a maximum source size of 75000 km and a minimum altitude of 160000 km above the orbital plane for the prominence. The entropy landscape technique was applied to determine the system parameters of BV Cen. We find M1 = 1.18 +/-0.280.16Msolar and M2 = 1.05 +/-0.230.14Msolar and an orbital inclination of i = 53° +/- 4° at an optimal systemic velocity of ? = -22.3 km s-1. Finally, we also report on the previously unknown binarity of the G5IV star HD 220492.
Resumo:
In a global context of an emphasis on identity politics and a ‘cultural turn’ in social analysis, deep concern has been expressed about multiethnic Britain becoming a broken society with many ‘sleepwalking’ into segregation and separatism. Given the close correspondence between areas of acute ethnic segregation and those of multiple deprivation, intercommunal tensions have included disputes about the equitable allocation of scarce urban resources across ethnicity. This creates the possibility that urban programmes may inadvertently accentuate intercommunal tension and confound efforts to synchronise cohesion and inclusion agendas. Following recent debates about the implications of increased diversity, influenced by arguments that multiculturalism has encouraged ‘parallel lives’, an emergent policy framework emphasises more proactive integration to promote ‘common belonging’. Criticism of this agenda includes its confusion between community and social cohesion, and its disproportionate focus on cultural aspects such as identity formation and recognition, relative to structural issues of income and class. In exploring this contested terrain in Britain, the article suggests that the longer-term debate about segregation, deprivation and community differentials in Northern Ireland can offer useful insight for Britain’s policy discourse.
Resumo:
Purpose: The aim of this study is to compare the sensitivity of different metrics to detect differences in complexity of intensity modulated radiation therapy (IMRT) plans following upgrades, changes to planning parameters, and patient geometry. Correlations between complexity metrics are also assessed.
Resumo:
We present optical spectra of 403 stars and quasi-stellar objects in order to obtain distance limits towards intermediate- and high-velocity clouds (IHVCs), including new Fibre-fed Extended Range Optical Spectrograph (FEROS) observations plus archival ELODIE, FEROS, High Resolution Echelle Spectrometer (HIRES) and Ultraviolet and Visual Echelle Spectrograph (UVES) data. The non-detection of Ca II K interstellar (IS) absorption at a velocity of −130 to −60 km s−1 towards HDE 248894 (d ∼ 3 kpc) and HDE 256725 (d ∼ 8 kpc) in data at signal-to-noise ratio (S/N) > 450 provides a new firm lower distance limit of 8 kpc for the anti-centre shell HVC. Similarly, the non-detection of Ca II K IS absorption towards HD 86248 at S/N ∼ 500 places a lower distance limit of 7.6 kpc for Complex EP, unsurprising since this feature is probably related to the Magellanic System. The lack of detection of Na I D at S/N = 35 towards Mrk 595 puts an improved upper limit for the Na I column density of log (NNaD <) 10.95 cm−2 towards this part of the Cohen Stream where Ca II was detected by Wakker et al. Absorption at ∼ −40 km s−1 is detected in Na I D towards the Galactic star PG 0039+049 at S/N = 75, placing a firm upper distance limit of 1 kpc for the intermediate-velocity cloud south (IVS), where a tentative detection had previously been obtained by Centurion et al. Ca ´ II K and Na I D absorption is detected at −53 km s−1 towards HD 93521, which confirms the upper distance limit of 2.4 kpc for part of the IV arch complex obtained using the International Ultraviolet Explorer (IUE) data by Danly. Towards HD 216411 in Complex H a non-detection in Na D towards gas with log(NH I) = 20.69 cm−2 puts a lower distance limit of 6.6 kpc towards this HVC complex. Additionally, Na I D absorption is detected at −43.7 km s−1 in the star HD 218915 at a distance of 5.0 kpc in gas in the same region of the sky as Complex H. Finally, the Na I/Ca II and Ca II/H I ratios of the current sample are found to lie in the range observed for previous studies of IHVCs.
Resumo:
RATIONALE: Characterization of bacterial populations in infectious respiratory diseases will provide improved understanding of the relationship between the lung microbiota, disease pathogenesis and treatment outcomes.
OBJECTIVES: To comprehensively define lung microbiota composition during stable disease and exacerbation in bronchiectasis patients.
METHODS: Sputum was collected from patients when clinically stable and before and after completion of antibiotic treatment of exacerbations. Bacterial abundance and community composition were analyzed using anaerobic culture and 16S rDNA pyrosequencing.
MEASUREMENTS AND MAIN RESULTS: In clinically stable patients, aerobic and anaerobic bacteria were detected in 40/40 (100%) and 33/40 (83%) sputum samples, respectively. The dominant organisms cultured were P. aeruginosa (n=10 patients), H. influenzae (n=12), Prevotella (n=18) and Veillonella (n=13). Pyrosequencing generated over 150,000 sequences, representing 113 distinct microbial taxa; the majority of observed community richness resulted from taxa present in low abundance with similar patterns of phyla distribution in clinically stable patients and patients at the onset of exacerbation. Following treatment of exacerbation, there was no change in total (p=0.925), aerobic (p=0.917) or anaerobic (p=0.683) load and only a limited shift in community composition. Agreement for detection of bacteria by culture and pyrosequencing was good for aerobic bacteria such as P. aeruginosa (kappa=0.84) but poorer for other genera including anaerobes. Lack of agreement was largely due to bacteria been detected by pyrosequencing but not by culture.
CONCLUSIONS: A complex microbiota is present in the lungs of bronchiectasis patients which remains stable through treatment of exacerbations suggesting that changes in microbiota composition do not account for exacerbations.
Resumo:
Objective: This paper uses data provided by the Police Service for Northern Ireland (PSNI) to compare the characteristics and outcomes of reported sexual offences involving child and adult victims and explore the factors associated with case outcomes.
Method: PSNI provided data on 8,789 sexual offences recorded between April 2001 and March 2006. Case outcomes were based on whether a case was recorded by police as having sufficient evidence to summons, charge, or caution an offender (detected). Where an offender was summonsed, charged, or cautioned, this is classified as detection with a formal sanction. A case can also be classified as "detected" without a formal sanction. The analysis focused on two key categories of detection without formal sanction: cases in which the police deem there to be sufficient evidence to charge an offender but took no further action because the victim did not wish to prosecute, or because the police or the Public Prosecution Service (PPS) decided that no useful purpose would be served by proceeding.
Results: The analysis confirmed that the characteristics of recorded sexual offences involving adult and child victims vary significantly according to gender, offence type, the timing of report and victim-offender relationship. Almost half of child sex abuse cases are not detected by police and a quarter do not proceed through the criminal justice system because either the victim declines to prosecute or the Police/PPS decide not to proceed. Only one in five child cases involved detection with a formal sanction. Child groups with lower detection with formal sanction rates included children under 5, teenagers, those who do not report when the abuse occurs but disclose at a later date; and those who experience abuse at the hands of peers and adults known to them but not related. The analysis also highlighted variation in formal sanction rates depending on where the offence was reported.
Conclusions: Consideration needs to be given to improving the criminal justice response to specific child groups as well as monitoring detection rates in different police areas in order to address potential practice variation.
Practice implications: Consideration needs to be given to improving the professional response in relation to with particularly lower detection with formal sanction rates. There is also a need to monitor case outcomes to ensure that child victims in different areas receive a similar service.
Resumo:
Purpose: In this study the Octavius detector 729 ionization chamber (IC) array with the Octavius 4D phantom was characterized for flattening filter (FF) and flattening filter free (FFF) static and rotational beams. The device was assessed for verification with FF and FFF RapidArc treatment plans.
Methods: The response of the detectors to field size, dose linearity, and dose rate were assessed for 6 MV FF beams and also 6 and 10 MV FFF beams. Dosimetric and mechanical accuracy of the detector array within the Octavius 4D rotational phantom was evaluated against measurements made using semiflex and pinpoint ionization chambers, and radiochromic film. Verification FF and FFF RapidArc plans were assessed using a gamma function with 3%/3 mm tolerances and 2%/2 mm tolerances and further analysis of these plans was undertaken using film and a second detector array with higher spatial resolution.
Results: A warm-up dose of >6 Gy was required for detector stability. Dose-rate measurements were stable across a range from 0.26 to 15 Gy/min and dose response was linear, although the device overestimated small doses compared with pinpoint ionization chamber measurements. Output factors agreed with ionization chamber measurements to within 0.6% for square fields of side between 3 and 25 cm and within 1.2% for 2 x 2 cm(2) fields. The Octavius 4D phantom was found to be consistent with measurements made with radiochromic film, where the gantry angle was found to be within 0.4. of that expected during rotational deliveries. RapidArc FF and FFF beams were found to have an accuracy of >97.9% and >90% of pixels passing 3%/3 mm and 2%/2 mm, respectively. Detector spatial resolution was observed to be a factor in determining the accurate delivery of each plan, particularly at steep dose gradients. This was confirmed using data from a second detector array with higher spatial resolution and with radiochromic film.
Conclusions: The Octavius 4D phantom with associated Octavius detector 729 ionization chamber array is a dosimetrically and mechanically stable device for pretreatment verification of FF and FFF RapidArc treatments. Further improvements may be possible through use of a detector array with higher spatial resolution (detector size and/or detector spacing). (C) 2013 American Association of Physicists in Medicine.
Resumo:
Resumo:
Evidence is presented from publicly available remotely operated vehicle (ROV) footage that suggests deep-water ranging in ocean sunfishes (family Molidae) is more common than typically thought, including a new maximum depth recorded for the southern sunfish Mola ramsayi.
Resumo:
O presente trabalho pretende apresentar uma investigação qualitativa que procurou conhecer o quotidiano de presidentes do conselho executivo de escolas secundárias públicas portuguesas. Esta investigação desenvolveu-se utilizando a metodologia de observação participante e de “shadowing” dos presidentes do conselho executivo que aceitaram participar no estudo. Para tal, acompanhámos 3 presidentes do conselho executivo de escolas secundárias públicas portuguesas durante algumas semanas de um ano lectivo, registando todos os elementos que compuseram o seu quotidiano e realizando entrevistas, quer com os presidentes, quer com outros elementos da equipa do conselho executivo. Os dados recolhidos foram analisados utilizando diversos enquadramentos teóricos de liderança e permitiram-nos caracterizar não só o quotidiano típico destes profissionais, mas também qual o seu papel na gestão e liderança da escola secundária pública em Portugal.
Resumo:
Barreiras para a precisão em radioterapia: delimitação de volumes, erros de posicionamento, movimento dos órgãos. Revolução imagiológica na monitorização do tratamento: radiografia, EPID, CONE-BEAM CT. Objectivo do estudo: quantificar desvios de posicionamento em doentes com patologias de cabeça e pescoço e próstata nos tratamentos de Radioterapia.
Resumo:
Consider the problem of scheduling a set of sporadic tasks on a multiprocessor system to meet deadlines using a tasksplitting scheduling algorithm. Task-splitting (also called semipartitioning) scheduling algorithms assign most tasks to just one processor but a few tasks are assigned to two or more processors, and they are dispatched in a way that ensures that a task never executes on two or more processors simultaneously. A certain type of task-splitting algorithms, called slot-based task-splitting, is of particular interest because of its ability to schedule tasks at high processor utilizations. We present a new schedulability analysis for slot-based task-splitting scheduling algorithms that takes the overhead into account and also a new task assignment algorithm.
Resumo:
Several projects in the recent past have aimed at promoting Wireless Sensor Networks as an infrastructure technology, where several independent users can submit applications that execute concurrently across the network. Concurrent multiple applications cause significant energy-usage overhead on sensor nodes, that cannot be eliminated by traditional schemes optimized for single-application scenarios. In this paper, we outline two main optimization techniques for reducing power consumption across applications. First, we describe a compiler based approach that identifies redundant sensing requests across applications and eliminates those. Second, we cluster the radio transmissions together by concatenating packets from independent applications based on Rate-Harmonized Scheduling.
Resumo:
The predominant clinical and radiological features of Langerhans' cell histiocytosis (LCH) in children are due to osseous involvement. Extra-osseous disease is far less common, occurring in association with bone disease or in isolation; nearly all anatomical sites may be affected and in very various combinations. The following article is based on a multicentre review of 31 children with extra-osseous LCH. The objective is to summarise the diverse possibilities of organ involvement. The radiological manifestations using different imaging modalities are rarely pathognomonic on their own. Nevertheless, familiarity with the imaging findings, especially in children with systemic disease, may be essential for early diagnosis.
Resumo:
Con información sobre la estructura poblacional de la Merluza Peruana obtenida mediante la aplicación del método de área de barrida (verano 1987), se plantea la aplicación de coherentes (POPE, 1972).