558 research outputs found
Resolving the complex structure of the dust torus in the active nucleus of the Circinus galaxy
To test the dust torus model for active galactic nuclei directly, we study
the extent and morphology of the nuclear dust distribution in the Circinus
galaxy using high resolution interferometric observations in the mid-infrared
with the MIDI instrument at the Very Large Telescope Interferometer. We find
that the dust distribution in the nucleus of Circinus can be explained by two
components, a dense and warm disk-like component of 0.4 pc size and a slightly
cooler, geometrically thick torus component with a size of 2.0 pc. The disk
component is oriented perpendicular to the ionisation cone and outflow and
seems to show the silicate feature at 10 micron in emission. It coincides with
a nuclear maser disk in orientation and size. From the energy needed to heat
the dust, we infer a luminosity of the accretion disk corresponding to 20% of
the Eddington luminosity of the nuclear black hole. We find that the
interferometric data are inconsistent with a simple, smooth and axisymmetric
dust emission. The irregular behaviour of the visibilities and the shallow
decrease of the dust temperature with radius provide strong evidence for a
clumpy or filamentary dust structure. We see no evidence for dust reprocessing,
as the silicate absorption profile is consistent with that of standard galactic
dust. We argue that the collimation of the ionising radiation must originate in
the geometrically thick torus component. Our findings confirm the presence of a
geometrically thick, torus-like dust distribution in the nucleus of Circinus,
as required in unified schemes of Seyfert galaxies. Several aspects of our data
require that this torus is irregular, or "clumpy".Comment: 20 pages, 16 figures, accepted for publication by A&
QUBIC: The QU Bolometric Interferometer for Cosmology
One of the major challenges of modern cosmology is the detection of B-mode
polarization anisotropies in the CMB. These originate from tensor fluctuations
of the metric produced during the inflationary phase. Their detection would
therefore constitute a major step towards understanding the primordial
Universe. The expected level of these anisotropies is however so small that it
requires a new generation of instruments with high sensitivity and extremely
good control of systematic effects. We propose the QUBIC instrument based on
the novel concept of bolometric interferometry, bringing together the
sensitivity advantages of bolometric detectors with the systematics effects
advantages of interferometry. Methods: The instrument will directly observe the
sky through an array of entry horns whose signals will be combined together
using an optical combiner. The whole set-up is located inside a cryostat.
Polarization modulation will be achieved using a rotating half-wave plate and
interference fringes will be imaged on two focal planes (separated by a
polarizing grid) tiled with bolometers. We show that QUBIC can be considered as
a synthetic imager, exactly similar to a usual imager but with a synthesized
beam formed by the array of entry horns. Scanning the sky provides an
additional modulation of the signal and improve the sky coverage shape. The
usual techniques of map-making and power spectrum estimation can then be
applied. We show that the sensitivity of such an instrument is comparable with
that of an imager with the same number of horns. We anticipate a low level of
beam-related systematics thanks to the fact that the synthesized beam is
determined by the location of the primary horns. Other systematics should be
under good control thanks to an autocalibration technique, specific to our
concept, that will permit the accurate determination of most of the systematics
parameters.Comment: 12 pages, 10 figures, submitted to Astronomy and Astrophysic
New Zealand blackcurrant extract enhances fat oxidation during prolonged cycling in endurance-trained females.
PURPOSE: New Zealand blackcurrant (NZBC) extract has previously been shown to increase fat oxidation during prolonged exercise, but this observation is limited to males. We examined whether NZBC intake also increases fat oxidation during prolonged exercise in females, and whether this was related to greater concentrations of circulating fatty acids. METHODS: In a randomised, crossover, double-blind design, 16 endurance-trained females (age: 28 ± 8 years, BMI: 21.3 ± 2.1 kg·m-2, VO2max: 43.7 ± 1.1 ml·kg-1·min-1) ingested 600 mg·day-1NZBC extract (CurraNZ™) or placebo (600 mg·day-1microcrystalline cellulose) for 7 days. On day 7, participants performed 120 min cycling at 65% VO2max, using online expired air sampling with blood samples collected at baseline and at 15 min intervals throughout exercise for analysis of glucose, NEFA and glycerol. RESULTS: NZBC extract increased mean fat oxidation by 27% during 120 min moderate-intensity cycling compared to placebo (P = 0.042), and mean carbohydrate oxidation tended to be lower (P = 0.063). Pre-exercise, plasma NEFA (P = 0.034) and glycerol (P = 0.051) concentrations were greater following NZBC intake, although there was no difference between conditions in the exercise-induced increase in plasma NEFA and glycerol concentrations (P > 0.05). Mean fat oxidation during exercise was moderately associated with pre-exercise plasma NEFA concentrations (r = 0.45, P = 0.016). CONCLUSIONS: Intake of NZBC extract for 7 days elevated resting concentrations of plasma NEFA and glycerol, indicative of higher lipolytic rates, and this may underpin the observed increase in fat oxidation during prolonged cycling in endurance-trained females
Meta-analysis of the detection of plant pigment concentrations using hyperspectral remotely sensed data
Passive optical hyperspectral remote sensing of plant pigments offers potential for understanding plant ecophysiological processes across a range of spatial scales. Following a number of decades of research in this field, this paper undertakes a systematic meta-analysis of 85 articles to determine whether passive optical hyperspectral remote sensing techniques are sufficiently well developed to quantify individual plant pigments, which operational solutions are available for wider plant science and the areas which now require greater focus. The findings indicate that predictive relationships are strong for all pigments at the leaf scale but these decrease and become more variable across pigment types at the canopy and landscape scales. At leaf scale it is clear that specific sets of optimal wavelengths can be recommended for operational methodologies: total chlorophyll and chlorophyll a quantification is based on reflectance in the green (550–560nm) and red edge (680–750nm) regions; chlorophyll b on the red, (630–660nm), red edge (670–710nm) and the near-infrared (800–810nm); carotenoids on the 500–580nm region; and anthocyanins on the green (550–560nm), red edge (700–710nm) and near-infrared (780–790nm). For total chlorophyll the optimal wavelengths are valid across canopy and landscape scales and there is some evidence that the same applies for chlorophyll a
Wound dressings for a proteolytic-rich environment
Wound dressings have experienced continuous and significant changes over the years based on the knowledge of the biochemical events associated with chronic wounds. The development goes from natural
materials used to just cover and conceal the wound to interactive materials that can facilitate the healing process, addressing specific issues in non-healing wounds. These
new types of dressings often relate with the proteolytic wound environment and the bacteria load to enhance the healing. Recently, the wound dressing research is focusing on the replacement of synthetic polymers by natural protein materials to delivery bioactive agents to the wounds. This
article provides an overview on the novel protein-based wound dressings such as silk fibroin keratin and elastin.
The improved properties of these dressings, like the release of antibiotics and growth factors, are discussed. The different types of wounds and the effective parameters of
healing process will be reviewed
On the mechanisms governing gas penetration into a tokamak plasma during a massive gas injection
A new 1D radial fluid code, IMAGINE, is used to simulate the penetration of gas into a tokamak plasma during a massive gas injection (MGI). The main result is that the gas is in general strongly braked as it reaches the plasma, due to mechanisms related to charge exchange and (to a smaller extent) recombination. As a result, only a fraction of the gas penetrates into the plasma. Also, a shock wave is created in the gas which propagates away from the plasma, braking and compressing the incoming gas. Simulation results are quantitatively consistent, at least in terms of orders of magnitude, with experimental data for a D 2 MGI into a JET Ohmic plasma. Simulations of MGI into the background plasma surrounding a runaway electron beam show that if the background electron density is too high, the gas may not penetrate, suggesting a possible explanation for the recent results of Reux et al in JET (2015 Nucl. Fusion 55 093013)
Early toxicity predicts long-term survival in high-grade glioma
BACKGROUND: Patients with high-grade gliomas are treated with surgery followed by chemoradiation. The risk factors and implications of neurological side effects are not known.
METHODS: Acute and late ≥ grade 3 neurological toxicities (NTs) were analysed among 2761 patients from 14 RTOG trials accrued from 1983 to 2003. The association between acute and late toxicity was analysed using a stepwise logistic regression model. The association between the occurrence of acute NT and survival was analysed as an independent variable.
RESULTS: There were 2610 analysable patients (86% glioblastoma, 10% anaplastic astrocytoma). All received a systemic agent during radiation (83% chemotherapy, 17% biological agents). Median radiation dose was 60 Gy. There were 182 acute and 83 late NT events. On univariate analysis, older age, poor performance status, aggressive surgery, pre-existing neurological dysfunction, poor mental status and twice-daily radiation were associated with increased acute NT. In a stepwise logistic regression model the occurrence of acute NT was significantly associated with late NT (OR=2.40; 95% CI=1.2-4.8; P=0.014). The occurrence of acute NT predicted poorer overall survival, independent of recursive partitioning analysis class (median 7.8 vs 11.8 months).
INTERPRETATION: Acute NT is significantly associated with both late NT and overall survival
Cloud Material Handling Systems: Conceptual Model and Cloud-Based Scheduling of Handling Activities
Nowadays, the implementation of cloud manufacturing technologies epitomizes the avant-garde in production systems. This affects several aspects of the management of these production systems, in particular scheduling activities, due to the possibility provided by cloud manufacturing of having real-time information about the stages of a product life cycle and about the status of all services. However, so far, cloud manufacturing has mainly focused on machines, with limited interest in material handling systems. This shortfall has been addressed in this study, where a new material-handling paradigm, called Cloud Material Handling System (CMHS) and developed in the Logistics 4.0 Lab at NTNU (Norway), has been introduced. With CMHS, the scheduling of the Material Handling Modules (MHMs) can be optimized, increasing the flexibility and productivity of the overall manufacturing system. To achieve this, the integration of advanced industry 4.0 technologies such as Internet of Things (IoT), and in particular Indoor Positioning Technologies (IPT), Cloud Computing, Machine Learning (ML), and Artificial Intelligence (AI), is required. In fact, based on the relevant information provided on the cloud platform by IPT and IoT for each product, called Smart Object (SO) (position, physical characteristics and so on), an Intelligent Cognitive Engine (ICE) can use ML and AI to decide, in real time, which MHM is most suitable for carrying out the tasks required by these products based on a compatibility matrix, on their attributes, and on the defined scheduling procedure.acceptedVersio
Study protocol for a group randomized controlled trial of a classroom-based intervention aimed at preventing early risk factors for drug abuse: integrating effectiveness and implementation research
<p>Abstract</p> <p>Background</p> <p>While a number of preventive interventions delivered within schools have shown both short-term and long-term impact in epidemiologically based randomized field trials, programs are not often sustained with high-quality implementation over time. This study was designed to support two purposes. The first purpose was to test the effectiveness of a universal classroom-based intervention, the Whole Day First Grade Program (WD), aimed at two early antecedents to drug abuse and other problem behaviors, namely, aggressive, disruptive behavior and poor academic achievement. The second purpose--the focus of this paper--was to examine the utility of a multilevel structure to support high levels of implementation during the effectiveness trial, to sustain WD practices across additional years, and to train additional teachers in WD practices.</p> <p>Methods</p> <p>The WD intervention integrated three components, each previously tested separately: classroom behavior management; instruction, specifically reading; and family-classroom partnerships around behavior and learning. Teachers and students in 12 schools were randomly assigned to receive either the WD intervention or the standard first-grade program of the school system (SC). Three consecutive cohorts of first graders were randomized within schools to WD or SC classrooms and followed through the end of third grade to test the effectiveness of the WD intervention. Teacher practices were assessed over three years to examine the utility of the multilevel structure to support sustainability and scaling-up.</p> <p>Discussion</p> <p>The design employed in this trial appears to have considerable utility to provide data on WD effectiveness and to inform the field with regard to structures required to move evidence-based programs into practice.</p> <p>Trial Registration</p> <p><b>Clinical Trials Registration Number</b>: NCT00257088</p
Effectiveness of temozolomide for primary glioblastoma multiforme in routine clinical practice
Temozolomide has been used as a standard therapy for the treatment of newly diagnosed glioblastoma multiforme since 2005. To assess the effectiveness of temozolomide in routine clinical practice, we conducted an observational study at Maastricht University Medical Centre (MUMC). Data of patients receiving radiotherapy and temozolomide between January 2005 and January 2008 were retrieved from a clinical database (radiochemotherapy group), as were data of patients in a historical control group from the period before 2005 treated with radiotherapy only (radiotherapy group). The primary endpoint was overall survival. A total of 125 patients with GBM were selected to form the study cohort. Median survival benefit was 4 months: the median overall survival was 12 months (95% CI, 9.7–14.3) in the group with radiochemotherapy with temozolomide, versus 8 months (95% CI, 5.3–10.7) in the group with only radiotherapy. Progression-free survival was 7 months (95% CI, 5.5–8.5) in the radiochemotherapy group and 4 months (95% CI, 2.9-5.1) in the group with only radiotherapy. The two-year survival rate was 18% with radiochemotherapy with temozolomide against 4% with radiotherapy alone. Concomitant treatment with radiotherapy and temozolomide followed by adjuvant temozolomide resulted in grade III or IV haematological toxic effects in 9% of patients. The addition of temozolomide to radiotherapy in routine clinical practice for newly diagnosed glioblastoma resulted in a clinically meaningful survival benefit with minimal haematological toxicity, which confirms the experience of previous trials and justifies the continued use of temozolomide in routine clinical practice
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