Automatic understanding of multimodal content for Web-based learning

Web-based learning has become an integral part of everyday life for all ages and backgrounds. On the one hand, the advantages of this learning type, such as availability, accessibility, flexibility, and cost, are apparent. On the other hand, the oversupply of content can lead to learners struggling to find optimal resources efficiently. The interdisciplinary research field Search as Learning is concerned with the analysis and improvement of Web-based learning processes, both on the learner and the computer science side. So far, automatic approaches that assess and recommend learning resources in Search as Learning (SAL) focus on textual, resource, and behavioral features. However, these approaches commonly ignore multimodal aspects. This work addresses this research gap by proposing several approaches that address the question of how multimodal retrieval methods can help support learning on the Web. First, we evaluate whether textual metadata of the TIB AV-Portal can be exploited and enriched by semantic word embeddings to generate video recommendations and, in addition, a video summarization technique to improve exploratory search. Then we turn to the challenging task of knowledge gain prediction that estimates the potential learning success given a specific learning resource. We used data from two user studies for our approaches. The first one observes the knowledge gain when learning with videos in a Massive Open Online Course (MOOC) setting, while the second one provides an informal Web-based learning setting where the subjects have unrestricted access to the Internet. We then extend the purely textual features to include visual, audio, and cross-modal features for a holistic representation of learning resources. By correlating these features with the achieved knowledge gain, we can estimate the impact of a particular learning resource on learning success. We further investigate the influence of multimodal data on the learning process by examining how the combination of visual and textual content generally conveys information. For this purpose, we draw on work from linguistics and visual communications, which investigated the relationship between image and text by means of different metrics and categorizations for several decades. We concretize these metrics to enable their compatibility for machine learning purposes. This process includes the derivation of semantic image-text classes from these metrics. We evaluate all proposals with comprehensive experiments and discuss their impacts and limitations at the end of the thesis.Web-basiertes Lernen ist ein fester Bestandteil des Alltags aller Alters- und Bevölkerungsschichten geworden. Einerseits liegen die Vorteile dieser Art des Lernens wie Verfügbarkeit, Zugänglichkeit, Flexibilität oder Kosten auf der Hand. Andererseits kann das Überangebot an Inhalten auch dazu führen, dass Lernende nicht in der Lage sind optimale Ressourcen effizient zu finden. Das interdisziplinäre Forschungsfeld Search as Learning beschäftigt sich mit der Analyse und Verbesserung von Web-basierten Lernprozessen. Bisher sind automatische Ansätze bei der Bewertung und Empfehlung von Lernressourcen fokussiert auf monomodale Merkmale, wie Text oder Dokumentstruktur. Die multimodale Betrachtung ist hingegen noch nicht ausreichend erforscht. Daher befasst sich diese Arbeit mit der Frage wie Methoden des Multimedia Retrievals dazu beitragen können das Lernen im Web zu unterstützen. Zunächst wird evaluiert, ob textuelle Metadaten des TIB AV-Portals genutzt werden können um in Verbindung mit semantischen Worteinbettungen einerseits Videoempfehlungen zu generieren und andererseits Visualisierungen zur Inhaltszusammenfassung von Videos abzuleiten. Anschließend wenden wir uns der anspruchsvollen Aufgabe der Vorhersage des Wissenszuwachses zu, die den potenziellen Lernerfolg einer Lernressource schätzt. Wir haben für unsere Ansätze Daten aus zwei Nutzerstudien verwendet. In der ersten wird der Wissenszuwachs beim Lernen mit Videos in einem MOOC-Setting beobachtet, während die zweite eine informelle web-basierte Lernumgebung bietet, in der die Probanden uneingeschränkten Internetzugang haben. Anschließend erweitern wir die rein textuellen Merkmale um visuelle, akustische und cross-modale Merkmale für eine ganzheitliche Darstellung der Lernressourcen. Durch die Korrelation dieser Merkmale mit dem erzielten Wissenszuwachs können wir den Einfluss einer Lernressource auf den Lernerfolg vorhersagen. Weiterhin untersuchen wir wie verschiedene Kombinationen von visuellen und textuellen Inhalten Informationen generell vermitteln. Dazu greifen wir auf Arbeiten aus der Linguistik und der visuellen Kommunikation zurück, die seit mehreren Jahrzehnten die Beziehung zwischen Bild und Text untersucht haben. Wir konkretisieren vorhandene Metriken, um ihre Verwendung für maschinelles Lernen zu ermöglichen. Dieser Prozess beinhaltet die Ableitung semantischer Bild-Text-Klassen. Wir evaluieren alle Ansätze mit umfangreichen Experimenten und diskutieren ihre Auswirkungen und Limitierungen am Ende der Arbeit

Effect of Growth Hormone (hGH) Replacement Therapy on Physical Work Capacity and Cardiac and Pulmonary Function in Patients with hGH Deficiency Acquired in Adulthood.

The effects of 6 months of replacement therapy with recombinant human GH (hGH) on physical work capacity and cardiac structure and function were investigated in 20 patients with hGH deficiency of adult onset in a double blind, placebo-controlled trial. The GH dose of 12.5 micrograms/kg BW was self-administered daily sc. Oxygen consumption (VO2), CO2 production, and ventilatory volumes were measured during exercise on a bicycle spiroergometer. M-Mode echocardiography was performed using standard techniques. The VO2 max data, expressed per kg BW (mL/min.kg BW) showed a significant increase from 23.2 +/- 2.4 to 30.0 +/- 2.3 (P < 0.01) in the hGH-treated group, whereas the VO2 max data, expressed per lean body mass (milliliters per min/kg lean body mass) did not change significantly in either group. Maximal O2 pulse (milliliters per beat) increased significantly from 15.2 +/- 5.6 to 19.6 +/- 3.3 mL/beat (P < 0.01), but remained constant in the placebo group. The maximal power output (watts +/- SE) increased significantly (P < 0.01) from 192.5 +/- 13.5 to 227.5 +/- 11.5 in the hGH-treated group, but remained constant in the placebo group. Cardiac structure (left ventricular posterior wall, interventricular septum thickness, left ventricular mass, left ventricular end-systolic dimension, and left ventricular end-diastolic dimension) as well as echocardiographically assessed cardiac function did not change significantly after 6 months of treatment in either group. We conclude that hGH replacement in hGH-deficient adults improves oxygen uptake and exercise capacity. These improvements in pulmonary parameters might be due to an increase in respiratory muscle strength and partly to the changes in muscle volume per se observed during hGH replacement therapy. Furthermore, an increased cardiac output might contribute to the improvement in exercise performance during hGH treatment. According to our data, hGH replacement therapy leads to an improvement of exercise capacity and maximal oxygen uptake, but has no significant effect on cardiac structure

Distinct causal influences of parietal versus frontal areas on human visual cortex: evidence from concurrent TMS-fMRI

It has often been proposed that regions of the human parietal and/or frontal lobe may modulate activity in visual cortex, for example, during selective attention or saccade preparation. However, direct evidence for such causal claims is largely missing in human studies, and it remains unclear to what degree the putative roles of parietal and frontal regions in modulating visual cortex may differ. Here we used transcranial magnetic stimulation (TMS) and functional magnetic resonance imaging (fMRI) concurrently, to show that stimulating right human intraparietal sulcus (IPS, at a site previously implicated in attention) elicits a pattern of activity changes in visual cortex that strongly depends on current visual context. Increased intensity of IPS TMS affected the blood oxygen level–dependent (BOLD) signal in V5/MT+ only when moving stimuli were present to drive this visual region, whereas TMS-elicited BOLD signal changes were observed in areas V1–V4 only during the absence of visual input. These influences of IPS TMS upon remote visual cortex differed significantly from corresponding effects of frontal (eye field) TMS, in terms of how they related to current visual input and their spatial topography for retinotopic areas V1–V4. Our results show directly that parietal and frontal regions can indeed have distinct patterns of causal influence upon functional activity in human visual cortex. Key words: attention, frontal cortex, functional magnetic resonance imaging, parietal cortex, top--down, transcranial magnetic stimulatio

Studying the Role of Human Parietal Cortex in Visuospatial Attention with Concurrent TMS-fMRI

Combining transcranial magnetic stimulation (TMS) with concurrent functional magnetic resonance imaging (fMRI) allows study of how local brain stimulation may causally affect activity in remote brain regions. Here, we applied bursts of high- or low-intensity TMS over right posterior parietal cortex, during a task requiring sustained covert visuospatial attention to either the left or right hemifield, or in a neutral control condition, while recording blood oxygenation-level-dependent signal with a posterior MR surface coil. As expected, the active attention conditions activated components of the well-described "attention network,” as compared with the neutral baseline. Also as expected, when comparing left minus right attention, or vice versa, contralateral occipital visual cortex was activated. The critical new finding was that the impact of high- minus low-intensity parietal TMS upon these visual regions depended on the currently attended side. High- minus low-intensity parietal TMS increased the difference between contralateral versus ipsilateral attention in right extrastriate visual cortex. A related albeit less pronounced pattern was found for left extrastriate visual cortex. Our results confirm that right human parietal cortex can exert attention-dependent influences on occipital visual cortex and provide a proof of concept for the use of concurrent TMS-fMRI in studying how remote influences can vary in a purely top-down manner with attentional demand

Risk Assessment for Patients with Chronic Respiratory Conditions in the Context of the SARS-CoV-2 Pandemic Statement of the German Respiratory Society with the Support of the German Association of Chest Physicians

Assessing the risk for specific patient groups to suffer from severe courses of COVID-19 is of major importance in the current SARS-CoV-2 pandemic. This review focusses on the risk for specific patient groups with chronic respiratory conditions, such as patients with asthma, chronic obstructive pulmonary disease, cystic fibrosis (CF), sarcoidosis, interstitial lung diseases, lung cancer, sleep apnea, tuberculosis, neuromuscular diseases, a history of pulmonary embolism, and patients with lung transplants. Evidence and recommendations are detailed in exemplary cases. While some patient groups with chronic respiratory conditions have an increased risk for severe courses of COVID-19, an increasing number of studies confirm that asthma is not a risk factor for severe COVID-19. However, other risk factors such as higher age, obesity, male gender, diabetes, cardiovascular diseases, chronic kidney or liver disease, cerebrovascular and neurological disease, and various immunodeficiencies or treatments with immunosuppressants need to be taken into account when assessing the risk for severe COVID-19 in patients with chronic respiratory diseases

Ensemble-based satellite-derived carbon dioxide and methane column-averaged dry-air mole fraction data sets (2003-2018) for carbon and climate applications

Satellite retrievals of column-averaged dry-air mole fractions of carbon dioxide (CO₂) and methane (CH₄), denoted XCO₂ and XCH₄, respectively, have been used in recent years to obtain information on natural and anthropogenic sources and sinks and for other applications such as comparisons with climate models. Here we present new data sets based on merging several individual satellite data products in order to generate consistent long-term climate data records (CDRs) of these two Essential Climate Variables (ECVs). These ECV CDRs, which cover the time period 2003–2018, have been generated using an ensemble of data products from the satellite sensors SCIAMACHY/ENVISAT and TANSO-FTS/GOSAT and (for XCO₂) for the first time also including data from the Orbiting Carbon Observatory 2 (OCO-2) satellite. Two types of products have been generated: (i) Level 2 (L2) products generated with the latest version of the ensemble median algorithm (EMMA) and (ii) Level 3 (L3) products obtained by gridding the corresponding L2 EMMA products to obtain a monthly 5∘×5∘ data product in Obs4MIPs (Observations for Model Intercomparisons Project) format. The L2 products consist of daily NetCDF (Network Common Data Form) files, which contain in addition to the main parameters, i.e., XCO₂ or XCH₄, corresponding uncertainty estimates for random and potential systematic uncertainties and the averaging kernel for each single (quality-filtered) satellite observation. We describe the algorithms used to generate these data products and present quality assessment results based on comparisons with Total Carbon Column Observing Network (TCCON) ground-based retrievals. We found that the XCO₂ Level 2 data set at the TCCON validation sites can be characterized by the following figures of merit (the corresponding values for the Level 3 product are listed in brackets) – single-observation random error (1σ): 1.29 ppm (monthly: 1.18 ppm); global bias: 0.20 ppm (0.18 ppm); and spatiotemporal bias or relative accuracy (1σ): 0.66 ppm (0.70 ppm). The corresponding values for the XCH₄ products are single-observation random error (1σ): 17.4 ppb (monthly: 8.7 ppb); global bias: −2.0 ppb (−2.9 ppb); and spatiotemporal bias (1σ): 5.0 ppb (4.9 ppb). It has also been found that the data products exhibit very good long-term stability as no significant long-term bias trend has been identified. The new data sets have also been used to derive annual XCO₂ and XCH₄ growth rates, which are in reasonable to good agreement with growth rates from the National Oceanic and Atmospheric Administration (NOAA) based on marine surface observations. The presented ECV data sets are available (from early 2020 onwards) via the Climate Data Store (CDS, https://cds.climate.copernicus.eu/, last access: 10 January 2020) of the Copernicus Climate Change Service (C3S, https://climate.copernicus.eu/, last access: 10 January 2020)

DNA methylome analysis in Burkitt and follicular lymphomas identifies differentially methylated regions linked to somatic mutation and transcriptional control

Although Burkitt lymphomas and follicular lymphomas both have features of germinal center B cells, they are biologically and clinically quite distinct. Here we performed whole-genome bisulfite, genome and transcriptome sequencing in 13 IG-MYC translocation-positive Burkitt lymphoma, nine BCL2 translocation-positive follicular lymphoma and four normal germinal center B cell samples. Comparison of Burkitt and follicular lymphoma samples showed differential methylation of intragenic regions that strongly correlated with expression of associated genes, for example, genes active in germinal center dark-zone and light-zone B cells. Integrative pathway analyses of regions differentially methylated in Burkitt and follicular lymphomas implicated DNA methylation as cooperating with somatic mutation of sphingosine phosphate signaling, as well as the TCF3-ID3 and SWI/SNF complexes, in a large fraction of Burkitt lymphomas. Taken together, our results demonstrate a tight connection between somatic mutation, DNA methylation and transcriptional control in key B cell pathways deregulated differentially in Burkitt lymphoma and other germinal center B cell lymphomas

Planetary Defense Ground Zero: MASCOT's View on the Rocks - an Update between First Images and Sample Return

At 01:57:20 UTC on October 3rd, 2018, after 3½ years of cruise aboard the JAXA spacecraft HAYABUSA2 and about 3 months in the vicinity of its target, the MASCOT lander was separated successfully by from an altitude of 41 m. After a free-fall of only ~5m51s MASCOT made first contact with C-type near-Earth and potentially hazardous asteroid (162173) Ryugu, by hitting a big boulder. MASCOT then bounced for ~11m3s, in the process already gathering valuable information on mechanical properties of the surface before it came to rest. It was able to perform science measurements at 3 different locations on the surface of Ryugu and took many images of its spectacular pitch-black landscape. MASCOT’s payload suite was designed to investigate the fine-scale structure, multispectral reflectance, thermal characteristics and magnetic properties of the surface. Somewhat unexpectedly, MASCOT encountered very rugged terrain littered with large surface boulders. Observing in-situ, it confirmed the absence of fine particles and dust as already implied by the remote sensing instruments aboard the HAYABUSA2 spacecraft. After some 17h of operations, MASCOT‘s mission ended with the last communication contact as it followed Ryugu’s rotation beyond the horizon as seen from HAYABUSA2. Soon after, its primary battery was depleted. We present a broad overview of the recent scientific results of the MASCOT mission from separation through descent, landing and in-situ investigations on Ryugu until the end of its operation and relate them to the needs of planetary defense interactions with asteroids. We also recall the agile, responsive and sometimes serendipitous creation of MASCOT, the two-year rush of building and delivering it to JAXA’s HAYABUSA2 spacecraft in time for launch, and the four years of in-flight operations and on-ground testing to make the most of the brief on-surface mission