3D scanning particle tracking velocimetry

In this article, we present an experimental setup and data processing schemes for 3D scanning particle tracking velocimetry (SPTV), which expands on the classical 3D particle tracking velocimetry (PTV) through changes in the illumination, image acquisition and analysis. 3D PTV is a flexible flow measurement technique based on the processing of stereoscopic images of flow tracer particles. The technique allows obtaining Lagrangian flow information directly from measured 3D trajectories of individual particles. While for a classical PTV the entire region of interest is simultaneously illuminated and recorded, in SPTV the flow field is recorded by sequential tomographic high-speed imaging of the region of interest. The advantage of the presented method is a considerable increase in maximum feasible seeding density. Results are shown for an experiment in homogenous turbulence and compared with PTV. SPTV yielded an average 3,500 tracked particles per time step, which implies a significant enhancement of the spatial resolution for Lagrangian flow measurement

Faktorer som kan påvirke pasienters intensjon om å bruke en digital løsning for postoperativ oppfølging : En kvalitativ studie blant pasienter som har gjennomgått elektiv kirurgi ved et sykehus i helse sør-øst

Master's thesis in Health informatics (HSI500)Background: Increasing volume of day surgery and a paradigm shift in patient care, has led to increased involvement of patients in the course of treatment, which requires good information, and good communication between the patient and health professionals. National health policy guidelines are suggesting that Internet-based services may be a key element to meet this need. For patients to use e-health solutions though, there must be an intention of use. Aim: The aim of this study was to explore what factors patients believe may affect their intention to use a service for digital post-operative follow-up after elective surgery. Sample and method: An interview guide was constructed with UTAUT 2 (Unified theory of acceptance and use of technology) and eHEALS (eHealth Literacy Scale) as frameworks. Eleven semi-structured interviews were conducted during the period January-February 2020. Data were analyzed in NvivoÒ, and both direct content analysis, and inductive content analysis were performed. The informants were patients who had underwent elective surgery during the last three months at the time of the interview

Automated, 3-D and Sub-Micron Accurate Ablation-Volume Determination by Inverse Molding and X-Ray Computed Tomography.

Ablation of materials in combination with element-specific analysis of the matter released is a widely used method to accurately determine a material's chemical composition. Among other methods, repetitive ablation using femto-second pulsed laser systems provides excellent spatial resolution through its incremental removal of nanometer thick layers. The method can be combined with high-resolution mass spectrometry, for example, laser ablation ionization mass spectrometry, to simultaneously analyze chemically the material released. With increasing depth of the volume ablated, however, secondary effects start to play an important role and the ablation geometry deviates substantially from the desired cylindrical shape. Consequently, primarily conical but sometimes even more complex, rather than cylindrical, craters are created. Their dimensions need to be analyzed to enable a direct correlation with the element-specific analytical signals. Here, a post-ablation analysis method is presented that combines generic polydimethylsiloxane-based molding of craters with the volumetric reconstruction of the crater's inverse using X-ray computed tomography. Automated analysis yields the full, sub-micron accurate anatomy of the craters, thereby a scalable and generic method to better understand the fundamentals underlying ablation processes applicable to a wide range of materials. Furthermore, it may serve toward a more accurate determination of heterogeneous material's composition for a variety of applications without requiring time- and labor-intensive analyses of individual craters

On the origin of 140 GHz emission from the 4 July 2012 solar flare

The sub-THz event observed on the 4 July 2012 with the Bauman Moscow State Technical University Radio Telescope RT-7.5 at 93 and 140~GHz as well as Kislovodsk and Mets\"ahovi radio telescopes, Radio Solar Telescope Network (RSTN), GOES, RHESSI, and SDO orbital stations is analyzed. The spectral flux between 93 and 140 GHz has been observed increasing with frequency. On the basis of the SDO/AIA data the differential emission measure has been calculated. It is shown that the thermal coronal plasma with the temperature above 0.5~MK cannot be responsible for the observed sub-THz flare emission. The non-thermal gyrosynchrotron mechanism can be responsible for the microwave emission near $10$~GHz but the observed millimeter spectral characteristics are likely to be produced by the thermal bremsstrahlung emission from plasma with a temperature of about 0.1~MK.Comment: 18 pages, 6 figure

Quantitative laser–matter interaction: a 3D study of UV-fs-laser ablation on single crystalline Ru(0001)

Laser ablation is nowadays an extensively applied technology to probe the chemical composition of solid materials. It allows for precise targeting of micrometer objects on and in samples, and enables chemical depth profiling with nanometer resolution. An in-depth understanding of the 3D geometry of the ablation craters is crucial for precise calibration of the depth scale in chemical depth profiles. Herein we present a comprehensive study on laser ablation processes using a Gaussian-shaped UV-femtosecond irradiation source and present how the combination of three different imaging methods (scanning electron microscopy, interferometric microscopy, and X-ray computed tomography) can provide accurate information on the crater’s shapes. Crater analysis by applying X-ray computed tomography is of considerable interest because it allows the imaging of an array of craters in one step with sub-µm accuracy and is not limited to the aspect ratio of the crater. X-ray computed tomography thereby complements the analysis of laser ablation craters. The study investigates the effect of laser pulse energy and laser burst count on a single crystal Ru(0001) sample. Single crystals ensure that there is no dependence on the grain orientations during the laser ablation process. An array of 156 craters of different dimensions ranging from <20 nm to ∼40 µm in depth were created. For each individually applied laser pulse, we measured the number of ions generated in the ablation plume with our laser ablation ionization mass spectrometer. We show to which extent the combination of these four techniques reveals valuable information on the ablation threshold, the ablation rate, and the limiting ablation depth. The latter is expected to be a consequence of decreasing irradiance upon increasing crater surface area. The ion signal generated was found to be proportional to the volume ablated up to the certain depth, which enables in-situ depth calibration during the measurement

Prognostic models in COVID-19 infection that predict severity: a systematic review.

Current evidence on COVID-19 prognostic models is inconsistent and clinical applicability remains controversial. We performed a systematic review to summarize and critically appraise the available studies that have developed, assessed and/or validated prognostic models of COVID-19 predicting health outcomes. We searched six bibliographic databases to identify published articles that investigated univariable and multivariable prognostic models predicting adverse outcomes in adult COVID-19 patients, including intensive care unit (ICU) admission, intubation, high-flow nasal therapy (HFNT), extracorporeal membrane oxygenation (ECMO) and mortality. We identified and assessed 314 eligible articles from more than 40 countries, with 152 of these studies presenting mortality, 66 progression to severe or critical illness, 35 mortality and ICU admission combined, 17 ICU admission only, while the remaining 44 studies reported prediction models for mechanical ventilation (MV) or a combination of multiple outcomes. The sample size of included studies varied from 11 to 7,704,171 participants, with a mean age ranging from 18 to 93 years. There were 353 prognostic models investigated, with area under the curve (AUC) ranging from 0.44 to 0.99. A great proportion of studies (61.5%, 193 out of 314) performed internal or external validation or replication. In 312 (99.4%) studies, prognostic models were reported to be at high risk of bias due to uncertainties and challenges surrounding methodological rigor, sampling, handling of missing data, failure to deal with overfitting and heterogeneous definitions of COVID-19 and severity outcomes. While several clinical prognostic models for COVID-19 have been described in the literature, they are limited in generalizability and/or applicability due to deficiencies in addressing fundamental statistical and methodological concerns. Future large, multi-centric and well-designed prognostic prospective studies are needed to clarify remaining uncertainties

Mediterranean winter rainfall in phase with African monsoons during the past 1.36 million years

Mediterranean climates are characterized by strong seasonal contrasts between dry summers and wet winters. Changes in winter rainfall are critical for regional socioeconomic development, but are difficult to simulate accurately1 and reconstruct on Quaternary timescales. This is partly because regional hydroclimate records that cover multiple glacial–interglacial cycles2,3 with different orbital geometries, global ice volume and atmospheric greenhouse gas concentrations are scarce. Moreover, the underlying mechanisms of change and their persistence remain unexplored. Here we show that, over the past 1.36 million years, wet winters in the northcentral Mediterranean tend to occur with high contrasts in local, seasonal insolation and a vigorous African summer monsoon. Our proxy time series from Lake Ohrid on the Balkan Peninsula, together with a 784,000-year transient climate model hindcast, suggest that increased sea surface temperatures amplify local cyclone development and refuel North Atlantic low-pressure systems that enter the Mediterranean during phases of low continental ice volume and high concentrations of atmospheric greenhouse gases. A comparison with modern reanalysis data shows that current drivers of the amount of rainfall in the Mediterranean share some similarities to those that drive the reconstructed increases in precipitation. Our data cover multiple insolation maxima and are therefore an important benchmark for testing climate model performance

Jämförelse av fallhändelsedokumentation före och efter införandet av en kvalitetsnorm för fallprevention

ABSTRACT Aim: The aim of this study was to examine differences in the documentation of the case incident reports, before (FRP) and after (FRE) the introduction of a quality standard for fall prevention in the geriatric departments at a Swedish University hospital. Method: 51 fall incident reports were collected before the introduction of quality standards for fall prevention and 63 after. Differences in documentation between the fall incident reports were analyzed with a Chi-2 test. Results: Number of case incidents in which the use of the alarm mat was documented increased after the introduction of quality standards for fall prevention and documented use of shoes and walker decreased. The majority of all documented case incidents occurred inside the patient room according to both FRP and FRE. Documented use of hypnotics increased, while the documented use of diuretics decreased between FRP and FRE. Documented time for falls has changed. For the FRP were these moments more often during the daytime (06:00 to 17:59) and for FRE were times more frequently during the night (18.00-05.59). Conclusion: There were many significant differences in documentation between the case incident reports FRP and FRI, what these differences is caused by is difficult to say, therefore, calls for further studies in which also a relationship between differences are examined. It would also be of interest to conduct studies with control groups to compare aid appliance use among patients who fall and don´t fall. Then the effect of aid appliances could be evaluated.SAMMANFATTNING Syfte: Syftet med studien var att undersöka skillnader i dokumentation av fallhändelserapporter före (FRP) och efter (FRE) införandet av en Kvalitetsnorm för fallprevention inom geriatrisk slutenvård vid ett universitetssjukhus i Sverige. Metod: Femtioen fallhändelserapporter samlades in före införandet av Kvalitetsnorm för fallprevention och 63 efter. Jämförbara variabler i dokumentationen identifierades och skillnader mellan fallhändelserapporterna analyserades med ett Chi-2 test. Resultat: Antal fallhändelserapporter där användandet av larmmatta var dokumenterat ökade efter införandet av Kvalitetsnorm för fallprevention och dokumenterat användande av skor och rollator minskade. Majoriteten av alla dokumenterade fallhändelser inträffade inne på patientsal enligt både FRP och FRE. Dokumenterad användning av hypnotika ökade, medan dokumenterad användning av diuretika minskade mellan FRP och FRE. Dokumenterade tidpunkter för fall har förändrats. På FRP var dessa tidpunkter oftare dagtid (06.00-17.59) och på FRE var tidpunkterna oftare nattetid (18.00-05.59).  Slutsats: Det fanns många signifikanta skillnader i dokumentationen mellan fallhändelserapporterna FRP och FRE, vad dessa skillnader beror på är dock svårt att säga, därför uppmanas det till fortsatta studier där även samband mellan skillnader undersöks. Det skulle även vara av intresse att genomföra studier med kontrollgrupper för att jämföra hjälpmedelsanvändning mellan patienter som faller och inte faller. Då skulle effekten av hjälpmedel kunna utvärderas