373 research outputs found

    Characterization of ultrasound fields using a potential optical flow based synthetic schlieren tomography

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    Synthetic schlieren tomography is an optical imaging method for characterization of ultrasound fields based on observing bending of light due to acousto-optic effect. In this work, potential optical flow based pressure estimation method is introduced

    Profiling water vapor mixing ratios in Finland by means of a Raman lidar, a satellite and a model

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    We present tropospheric water vapor profiles measured with a Raman lidar during three field campaigns held in Finland. Co-located radio soundings are available throughout the period for the calibration of the lidar signals. We investigate the possibility of calibrating the lidar water vapor profiles in the absence of co-existing on-site soundings using water vapor profiles from the combined Advanced InfraRed Sounder (AIRS) and the Advanced Microwave Sounding Unit (AMSU) satellite product; the Aire Limitee Adaptation dynamique Developpement INternational and High Resolution Limited Area Model (ALADIN/HIRLAM) numerical weather prediction (NWP) system, and the nearest radio sounding station located 100 km away from the lidar site (only for the permanent location of the lidar). The uncertainties of the calibration factor derived from the soundings, the satellite and the model data are <2.8, 7.4 and 3.9 %, respectively. We also include water vapor mixing ratio intercomparisons between the radio soundings and the various instruments/model for the period of the campaigns. A good agreement is observed for all comparisons with relative errors that do not exceed 50% up to 8 km altitude in most cases. A 4-year seasonal analysis of vertical water vapor is also presented for the Kuopio site in Finland. During winter months, the air in Kuopio is dry (1.15 +/- 0.40 g kg(-1)); during summer it is wet (5.54 +/- 1.02 g kg(-1)); and at other times, the air is in an intermediate state. These are averaged values over the lowest 2 km in the atmosphere. Above that height a quick decrease in water vapor mixing ratios is observed, except during summer months where favorable atmospheric conditions enable higher mixing ratio values at higher altitudes. Lastly, the seasonal change in disagreement between the lidar and the model has been studied. The analysis showed that, on average, the model underestimates water vapor mixing ratios at high altitudes during spring and summer.Peer reviewe

    Integrating Historical Person Registers as Linked Open Data in the WarSampo Knowledge Graph

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    Semantic data integration from heterogeneous, distributed data silos enables Digital Humanities research and application development employing a larger, mutually enriched and interlinked knowledge graph. However, data integration is challenging, involving aligning the data models and reconciling the concepts and named entities, such as persons and places. This paper presents a record linkage process to reconcile person references in different military historical person registers with structured metadata. The information about persons is aggregated into a single knowledge graph. The process was applied to reconcile three person registers of the popular semantic portal "WarSampo -- Finnish World War 2 on the Semantic Web". The registers contain detailed information about some 100,000 people and are individually maintained by domain experts. Thus, the integration process needs to be automatic and adaptable to changes in the registers. An evaluation of the record linkage results is promising and provides some insight into military person register reconciliation in general.Peer reviewe

    Metabarcoding successfully tracks temporal changes in eukaryotic communities in coastal sediments

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    Metabarcoding is a method that combines high-throughput DNA sequencing and DNA-based identification. Previously, this method has been successfully used to target spatial variation of eukaryote communities in marine sediments, however, the temporal changes in these communities remain understudied. Here, we follow the temporal changes of the eukaryote communities in Baltic Sea surface sediments collected from two coastal localities during three seasons of two consecutive years. Our study reveals that the structure of the sediment eukaryotic ecosystem was primarily driven by annual and seasonal changes in prevailing environmental conditions, whereas spatial variation was a less significant factor in explaining the variance in eukaryotic communities over time. Therefore, our data suggests that shifts in regional climate regime or large-scale changes in the environment are the overdriving factors in shaping the coastal eukaryotic sediment ecosystems rather than small-scale changes in local environmental conditions or heterogeneity in ecosystem structure. More studies targeting temporal changes are needed to further understand the long-term trends in ecosystem stability and response to climate change. Furthermore, this work contributes to the recent efforts in developing metabarcoding applications for environmental biomonitoring, proving a comprehensive option for traditional monitoring approaches.Peer reviewe

    Black Mesoporous Silicon as a Contrast Agent for LED-Based 3D Photoacoustic Tomography

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    Mesoporous silicon (PSi) nanoparticles have been widely studied in different biomedical imaging modalities due to their several beneficial material properties. However, they have not been found to be suitable for photoacoustic imaging due to their poor photothermal conversion performance. In the present study, biodegradable black mesoporous silicon (BPSi) nanoparticles with strong light absorbance were developed as superior image contrast agents for photoacoustic tomography (PAT), which was realized with a light-emitting diode (LED) instead of the commonly used laser. LED-based PAT offers the advantages of low cost, compactness, good mobility, and easy operation as compared to the traditional laser-based PAT modality. Nevertheless, the poor imaging sensitivity of the LED-PAT systems has been the main barrier to prevent their wide biomedical application because the LED light has low optical energy. The present study demonstrated that the imaging sensitivity of the LED-PAT system was significantly enhanced with the PEGylated BPSi (PEG–BPSi) nanoparticles. The PEG–BPSi nanoparticles were clearly detectable with a low concentration of 0.05 mg/mL in vitro and with an LED radiation energy of 5.2 μJ. The required concentration of the PEG–BPSi nanoparticles was 10 times lesser than that of the reference gold nanoparticles to reach the corresponding level of the imaging contrast. The ex vivo studies demonstrated that the submillimeter BPSi nanoparticle-based absorbers were distinguishable in chicken breast tissues. The strong contrast provided by the BPSi particles indicated that these particles can be utilized as novel contrast agents in PAT, especially in LED-based systems with low light intensity

    Lapsen osallisuuden tukeminen päiväkodin arjessa

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    Tiivistelmä. Tutkielmassamme avaamme osallisuuden käsitettä teorioiden, niiden tulkintojen sekä osallisuutta haastavien tekijöiden kautta. Olemme myös koonneet yhteen osallisuutta tukevia keinoja. Tutkimme näitä seuraavien tutkimuskysymysten kautta: miten osallisuutta on määritelty varhaiskasvatuksessa ja mitkä tekijät haastavat osallisuutta sekä miten lapsen osallisuutta voidaan tukea päiväkodin arjessa. Osallisuus tarkoittaa lapsen mahdollisuuksia vaikuttaa häntä koskeviin päätöksiin. Lapsen tulee myös olla tietoinen siitä, että hänen mielipiteensä vaikuttavat päätöksiin. Lasten osallisuutta voidaan tukea monella tavalla. Varhaiskasvatuksen opettaja on avainasemassa mahdollistamassa lapsen osallisuutta. Osallisuutta tuetaan kuuntelemalla lasta ja keskustelemalla hänen kanssaan, kodin ja päiväkodin välisellä yhteistyöllä, joustavilla rutiineilla ja pienryhmätoiminnalla päiväkodissa, lasten mielenkiinnonkohteiden huomioimisella sekä toiminnan havainnoinnilla ja sen mahdollistamisella. Tutkielmamme aihe on ajankohtainen ja aiheen valintaan ovat vaikuttaneet myös omat kokemuksemme. Lasten osallisuus varhaiskasvatuksessa on noussut ajankohtaiseksi aiheeksi varhaiskasvatuslain (540/2018) päivityksen myötä. Olemme myös havainneet itse päiväkodissa työskennellessämme, että varhaiskasvatuksen opettajien ajatukset lasten osallisuudesta ovat hyvin erilaisia. Tämän vuoksi, päädyimme tutkimaan lasten osallisuutta päiväkodin arjessa. Kandidaatin tutkielmamme on toteutettu integroivana kirjallisuuskatsauksena. Integroiva kirjallisuuskatsaus mahdollistaa laajan aineiston käytön sekä aineistojen yhdistelemisen ja uuden tiedon luomisen. Laaja aineisto mahdollistaa tutkielmamme luotettavuutta ja yleistettävyyttä. Olemme valinneet tutkielmaamme kattavasti erilaisia tutkimuksia, joiden pohjalta olemme muodostaneet monipuolisen käsityksen lapsen osallisuuden haasteista sekä sen tukemisesta. Tutkielmamme tavoitteena on tuoda konkreettisia esimerkkejä varhaiskasvatuksen opettajille siitä, miten lasten osallisuutta voidaan päiväkodin arjessa tukea

    Different Predictors of Right and Left Ventricular Metabolism in Healthy Middle-Aged Men

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    Dysfunction of the right ventricle (RV) plays a crucial role in the outcome of various cardiovascular diseases. Previous studies on RV metabolism are sparse although evidence implies it may differ from left ventricular (LV) metabolism. Therefore, the aims of this study were (1) to determine predictors of RV glucose uptake (GU) and free fatty acid uptake (FFAU) and (2) to compare them to predictors of LV metabolism in healthy middle-aged men. Altogether 28 healthy, sedentary, middle-aged (40-55 years) men were studied. Insulin-stimulated GU and fasting FFAU were measured by positron emission tomography and RV and LV structural and functional parameters by cardiac magnetic resonance. Several parameters related to whole-body health were also measured. Predictors of RV and LV metabolism were determined by pairwise correlation analysis, lasso regression models, and variable clustering using heatmap. RVGU was most strongly predicted by age and moderately by RV ejection fraction (EF). The strongest determinants of RVFFAU were exercise capacity (peak oxygen uptake), resting heart rate, LVEF, and whole body insulin stimulated glucose uptake rate. When considering LV metabolism, age and RVEF were associated also with LVGU. In addition, LVGU was strongly, and negatively, influenced by whole-body insulin-stimulated glucose uptake rate. LVFFAU was predicted only by LVEF. This study shows that while RV and LV metabolism have shared characteristics, they also have unique properties. Age of the subject should be taken into account when measuring myocardial glucose utilization. Ejection fraction is related to myocardial metabolism, and even so that RVEF may be more closely related to GU of both ventricles and LVEF to FFAU of both ventricles, a finding supporting the ventricular interdependence. However, only RV fatty acid utilization associates with exercise capacity so that better physical fitness in a relatively sedentary population is related with decreased RV fat metabolism. To conclude, this study highlights the need for further study designed specifically on less known RV as the results on LV metabolism and physiology may not be directly applicable to the RV.</p

    Evaluation of convective boundary layer height estimates using radars operating at different frequency bands

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    Knowledge of the atmospheric boundary layer state and evolution is important for understanding air pollution and low-level cloud development, among other things. There are a number of instruments and methods that are currently used to estimate boundary layer height (BLH). However, no single instrument is capable of providing BLH measurements in all weather conditions. We proposed a method to derive a daytime convective BLH using clear air echoes in radar observations and investigated the consistency of these retrievals between different radar frequencies. We utilized data from three vertically pointing radars that are available at the SMEAR II station in Finland, i.e. the C band (5 GHz), Ka band (35 GHz) and W band (94 GHz). The Ka- or W-band cloud radars are an integral part of cloud profiling stations of pan-European Aerosol, Clouds and Trace Gases Research Infrastructure (ACTRIS). Our method will be utilized at ACTRIS stations to serve as an additional estimate of the BLH during summer months. During this period, insects and Bragg scatter are often responsible for clear air echoes recorded by weather and cloud radars. To retrieve a BLH, we suggested a mechanism to separate passive and independently flying insects that works for all analysed frequency bands. At the lower frequency (the C band) insect scattering has been separated from Bragg scattering using a combination of the radar reflectivity factor and linear depolarization ratio. Retrieved values of the BLH from all radars are in a good agreement when compared to the BLH obtained with the co-located HALO Doppler lidar and ERA5 reanalysis data set. Our method showed some underestimation of the BLH after nighttime heavy precipitation yet demonstrated a potential to serve as a reliable method to obtain a BLH during clear-sky days. Additionally, the entrainment zone was observed by the C-band radar above the CBL in the form of a Bragg scatter layer. Aircraft observations of vertical profiles of potential temperature and water vapour concentration, collected in the vicinity of the radar, demonstrated some agreement with the Bragg scatter layer.Peer reviewe
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