Off-disk straylight measurements for the Swedish 1-meter Solar Telescope

Context. Accurate photometry with ground based solar telescopes requires characterization of straylight. Scattering in Earth's atmosphere and in the telescope optics are potentially significant sources of straylight, for which the point spread function (PSF) has wings that reach very far. This kind of straylight produces an aureola, extending several solar radii off the solar disk. Aims. We want to measure such straylight using the ordinary science instrumentation. Methods. We scanned the intensity on and far off the solar disk by use of the science cameras in several different wavelength bands on a day with low-dust conditions. We characterized the far wing straylight by fitting a model to the recorded intensities involving a multi-component straylight PSF and the limb darkening of the disk. Results. The measured scattered light adds an approximately constant fraction of the local granulation intensity to science images at any position on the disk. The fraction varied over the day but never exceeded a few percent. The PSFs have weak tails that extend to several solar radii but most of the scattered light originates within ~1'. Conclusions. Far-wing scattered light contributes only a small amount of straylight in SST data. Other sources of straylight are primarily responsible for the reduced contrast in SST images.Comment: Accepted for publication in Astronomy & Astrophysic

Increased number and altered phenotype of lymphatic vessels in peripheral lung compartments of patients with COPD

<p>Background De novo lymphatic vessel formation has recently been observed in lungs of patients with moderate chronic obstructive pulmonary disease (COPD). However, the distribution of lymphatic vessel changes among the anatomical compartments of diseased lungs is unknown. Furthermore, information regarding the nature of lymphatic vessel alterations across different stages of COPD is missing. This study performs a detailed morphometric characterization of lymphatic vessels in major peripheral lung compartments of patients with different severities of COPD and investigates the lymphatic expression of molecules involved in immune cell trafficking.</p> <p>Methods Peripheral lung resection samples obtained from patients with mild (GOLD stage I), moderate-severe (GOLD stage II-III), and very severe (GOLD stage IV) COPD were investigated for podoplanin-immunopositive lymphatic vessels in distinct peripheral lung compartments: bronchioles, pulmonary blood vessels and alveolar walls. Control subjects with normal lung function were divided into never smokers and smokers. Lymphatics were analysed by multiple morphological parameters, as well as for their expression of CCL21 and the chemokine scavenger receptor D6.</p> <p>Results The number of lymphatics increased by 133% in the alveolar parenchyma in patients with advanced COPD compared with never-smoking controls (p <0.05). In patchy fibrotic lesions the number of alveolar lymphatics increased 20-fold from non-fibrotic parenchyma in the same COPD patients. The absolute number of lymphatics per bronchiole and artery was increased in advanced COPD, but numbers were not different after normalization to tissue area. Increased numbers of CCL21- and D6-positive lymphatics were observed in the alveolar parenchyma in advanced COPD compared with controls (p <0.01). Lymphatic vessels also displayed increased mean levels of immunoreactivity for CCL21 in the wall of bronchioles (p < 0.01) and bronchiole-associated arteries (p < 0.05), as well as the alveolar parenchyma (p < 0.001) in patients with advanced COPD compared with never-smoking controls. A similar increase in lymphatic D6 immunoreactivity was observed in bronchioles (p <0.05) and alveolar parenchyma (p < 0.01).</p> <p>Conclusions This study shows that severe stages of COPD is associated with increased numbers of alveolar lymphatic vessels and a change in lymphatic vessel phenotype in major peripheral lung compartments. This novel histopathological feature is suggested to have important implications for distal lung immune cell traffic in advanced COPD.</p&gt

A model of quality assessment in patients on long-term oxygen therapy

SummaryBackgroundThe difficulty of implementing guidelines for long-term oxygen therapy (LTOT) has been recognized. We performed this analysis to evaluate the impact of a national quality assurance register on the quality of LTOT and to suggest indicators with levels for excellent quality LTOT.MethodsBased on national register data on Swedish LTOT patients in 1987–2005, we measured nine quality indicators and the achievement levels of the participating counties in fulfilling these treatment criteria.ResultsThere were improvements in the following eight quality indicators: access to LTOT, PaO2≤7.3kPa without oxygen, no current smoking, low number of thoracic deformity patients without concomitant home mechanical ventilation, >16h of oxygen/day, mobile oxygen equipment, reassessment of hypoxemia when LTOT was not started in a stable state of chronic obstructive pulmonary disease (COPD) and avoidance of continuous oral glucocorticosteroids in COPD. There was decline in the quality indicator PaO2>8kPa on oxygen. After improvements, three criteria were fulfilled by ≥80% of the counties in 2004–2005.ConclusionsWe found improvements in eight of nine quality indicators. We suggest these indicators with levels for excellent quality for use in quality assurance of LTOT based on our results

Gendered aspects of Leisure-time teachers' care - social and physical dimensions

This article aims to gain knowledge on how gender and profession are accounted for and expressed in leisure-time teachers’ (LtTs) work in Sweden, with a specific focus on the caring aspects of the profession. Our results show that LtTs take up various positions in navigating between aspects connected to managerialism and external auditing as well as trust and internal valuation. We argue that the need exists for an expanded understanding of care in order to recognise and reward various gendered actions and activities in teachers’ caring orientation. The article provides knowledge to both researchers and practitioners on gendered nuances of care that by tradition have been connected to women

Euromech Colloquium 509: Vehicle Aerodynamics. External Aerodynamics of Railway Vehicles, Trucks, Buses and Cars - Proceedings

During the 509th Colloquium of the Euromech society, held from March 24th & 25th at TU Berlin, fifty leading researchers from all over europe discussed various topics affecting both road vehicle as well as railway vehicle aerodynamics, especially drag reduction (with road vehicles), cross wind stability (with trains) and wake analysis (with both). With the increasing service speed of modern high-speed railway traffic, aerodynamic aspects are gaining importance. The aerodynamic research topics comprise both pure performance improvements, such as the continuous lowering of aerodynamic drag for energy efficiency, as well as safety relevant topics, such as cross-wind stability. The latter topic was most recently brought to attention when a swiss narrow-gauge train overturned during the severe storm Kyrill in january 2007. The shape of the train head usually has largest influence on cross wind stability. Slipstream effects of passing trains cause aerodynamic loads on objects and passengers waiting at platforms. The strength of the slipstream is determined by both the boundary layer development along the length of the train and the wake developing behind the tail of the train. Since high-speed trains can be considered to be as smooth as technically possible, attention is drawn to the wake region. The wake of the train again is also one important factor for the total drag of a train. Due to the fact that trains are bidirectional, optimisation of the leading car of a train with respect to drag and cross wind performance while simultaneously minimising the wake of the train for drag and slipstream performance is a great challenge. Modern optimisation tools are used to aid this multi-parameter multi-constraint design optimisation in conjunction with both CFD and wind tunnel investigations. Since many of the aerodynamic effects in the railway sector are of similar importance to road vehicles, the aim of the colloquium is to bridge the application of shape optimisation principles between rail- and road vehicles. Particular topics to be addressed in the colloquium are: Drag, Energy consumption and emissions: Due to increase in energy cost, drag reduction has gained focus in the past years and attention will grow in the future. Pressure induced drag is of common importance for both rail- and road vehicles. The optimisation of head- and tail shape for road vehicles as well as for bi-directional vehicles (trains) is in the focus. Interference drag between adjacent components shall also be treated. Slipstream Effects: Are a safety issue for high-train operation (Prams sucked into track due to train-induced draught flows) when trains passing platforms at high speeds. For Road vehicles, the ride stability of overtaking cars is influenced by the wake of the leading trucks and busses. Common interest is the minimisation of wake effects for both rail and road vehicles. Cross-Wind Safety, Ride stability under strong winds: Both are safety issues for rail- and road vehicles. Aerodynamic forces shall be minimised (roll moment for trains and also yaw moment for road vehicles). Strategies for Vehicle shape optimisation (head, tail and roof shape) in order to minimise aerodynamic moments. Possibilities of Flow control. Optimisation strategies: Parametrisation, analyses (CFD), Optimisation tools and methods, Application to Drag, Cross-Wind, Ride stability and Snow issue

Imaging Spectropolarimetry with IBIS II: on the fine structure of G-band bright features

We present new results from first observations of the quiet solar photosphere performed through the Interferometric BIdimensional Spectrometer (IBIS) in spectropolarimetric mode. IBIS allowed us to measure the four Stokes parameters in the FeI 630.15 nm and FeI 630.25 nm lines with high spatial and spectral resolutions for 53 minutes; the polarimetric sensitivity achieved by the instrument is 0.003 the continuum intensity level. We focus on the correlation which emerges between G-band bright feature brightness and magnetic filling factor of ~ 1000 G (kG) fields derived by inverting Stokes I and V profiles. More in detail, we present the correlation first in a pixel-by-pixel study of an approximatively 3 arcsec wide bright feature (a small network patch) and then we show that such a result can be extended to all the bright features found in the dataset at any instant of the time sequence. The higher the kG filling factor associated to a feature the higher the brightness of the feature itself. Filling factors up to about 35 % are obtained for the brightest features. Considering the values of the filling factors derived from the inversion analysis of spectropolarimetric data and the brightness variation observed in G-band data we put forward an upper limit for the smallest scale over which magnetic flux concentrations in intergranular lanes produce a G-band brightness enhancement (~ 0.1''). Moreover, the brightness saturation observed for feature sizes comparable to the resolution of the observations is compatible with large G-band bright features being clusters of sub-arcsecond bright points. This conclusion deserves to be confirmed by forthcoming spectropolarimetric observations at higher spatial resolution.Comment: 10 pages, 7 figures, 1 table - Accepted for publication on Ap

High-order aberration compensation with Multi-frame Blind Deconvolution and Phase Diversity image restoration techniques

Context. For accurately measuring intensities and determining magnetic field strengths of small-scale solar (magnetic) structure, knowledge of and compensation for the point spread function is crucial. For images recorded with the Swedish 1-meter Solar Telescope, restoration with Multi-Frame Blind Deconvolution and Joint Phase Diverse Speckle methods lead to remarkable improvements in image quality but granulation contrasts that are too low, indicating additional stray light. Aims. We propose a method to compensate for stray light from high-order atmospheric aberrations not included in MFBD and JPDS processing. Methods. To compensate for uncorrected aberrations, a reformulation of the image restoration process is proposed that allows the average effect of hundreds of high-order modes to be compensated for by relying on Kolmogorov statistics for these modes. The applicability of the method requires simultaneous measurements of Fried's parameter r0. The method is tested with simulations as well as real data and extended to include compensation for conventional stray light. Results. We find that only part of the reduction of granulation contrast in SST images is due to uncompensated high-order aberrations. The remainder is still unaccounted for and attributed to stray light from the atmosphere, the telescope with its re-imaging system and to various high-altitude seeing effects. Conclusions. We conclude that statistical compensation of high-order modes is a viable method to reduce the loss of contrast occurring when a limited number of aberrations is explicitly compensated for with MFBD and JPDS processing. We show that good such compensation is possible with only 10 recorded frames. The main limitation of the method is that already MFBD and JPDS processing introduces high-order compensation that, if not taken into account, can lead to over-compensation.Comment: in press in Astronomy & Astrophysic

Finns det några samband mellan skogsmarkens status och förekomsten av Geranium bohemicum på brandområden?

Geranium bohemicum är en brandgynnad art som etablerar sig efter skogsbränder från en långlivad fröbank. Sent i juli år 2014 startade en brand i Västmanlands län som skulle komma att bli den största på mer än 100 år i Sverige. Trots stora ekonomiska förluster och förödelse gav branden värdefullt substrat för G. bohemicum att växa och frodas i. För att ta reda på hur G. bohemicums utbredningsmönster ser ut och vad som kan ligga bakom krävs en kartläggning av G. bohemicum och en analys av skogsmarken. Min hypotes var att G. bohemicum förmodligen kräver mera näringsrik mark. Gran är normalt sett är det trädslag som förekommer på sådana marker vilket borde leda till en samvariation i deras utbredning. Studien visade att G. bohemicums distributionsmönster inte är ett resultat av slumpen. Det finns bakomliggande faktorer som spelar in på dess förekomst. Det visade sig att nävorna hade en tydlig dragning mot granmark framför tallmark. Granandelen var större i fyndplatslokalerna än generellt i området. Nävorna visade även en preferens för de lägre partierna i terrängen, företrädelsevis sedimentmarker. Näringsrika jordar och blottad mineraljord är viktiga förutsättningar för att G. bohemicum ska börja gro. Hyggen visade sig spela mindre roll för nävans utbredning. Andelen fyndplatslokaler på hyggen var lika stor som andelen hyggen i mitt avgränsade område vilket inte var särskilt konstigt då hela området var jämntorrt så skogsmark och hyggen brann lika bra.Geranium bohemicum is a fire prone species that establish after forest fires. In late July 2014 a forest fire started in Västmanlands County which would become the biggest fire in more than 100 year in Sweden. Even though huge losses and destruction the fire created valuable substrate for G. bohemicum to grow and thrive in. To find out how the spatial distribution of G. bohemicum is and what the underlying factors are mapping is required and an analysis of the forest ground. My hypothesis was that G. bohemicum most likely shows up on more nutrient rich soil and that spruce normally is the species that grow on such soils. The study showed that the distribution of G. bohemicum is not random. There is underlying factors that has effect of their existence. That it should have a preference for spruce ground before pine ground is proved. The proportion spruce was a lot bigger in the provenance than in in general in the area. The geraniums showed a preference for the lower parts of the terrain. Preferably sediment grounds. Nutrient rich soils and bare mineral soils are important conditions for G. bohemicum to start grow. Clear-cuts didn’t seem to play a big role for the distribution for G. bohemicum. The proportion clear-cuts in the proveniences was as big as in my defined area which was not unexpected because the hole area was dry and evenly burnt