Automated Processing of Webcam Images for Phenological Classification

Along with the global climate change, there is an increasing interest for its effect on phenological patterns such as start and end of the growing season. Scientific digital webcams are used for this purpose taking every day one or more images from the same natural motive showing for example trees or grassland sites. To derive phenological patterns from the webcam images, regions of interest are manually defined on these images by an expert and subsequently a time series of percentage greenness is derived and analyzed with respect to structural changes. While this standard approach leads to satisfying results and allows to determine dates of phenological change points, it is associated with a considerable amount of manual work and is therefore constrained to a limited number of webcams only. In particular, this forbids to apply the phenological analysis to a large network of publicly accessible webcams in order to capture spatial phenological variation. In order to be able to scale up the analysis to several hundreds or thousands of webcams, we propose and evaluate two automated alternatives for the definition of regions of interest, allowing for efficient analyses of webcam images. A semi-supervised approach selects pixels based on the correlation of the pixels’ time series of percentage greenness with a few prototype pixels. An unsupervised approach clusters pixels based on scores of a singular value decomposition. We show for a scientific webcam that the resulting regions of interest are at least as informative as those chosen by an expert with the advantage that no manual action is required. Additionally, we show that the methods can even be applied to publicly available webcams accessed via the internet yielding interesting partitions of the analyzed images. Finally, we show that the methods are suitable for the intended big data applications by analyzing 13988 webcams from the AMOS database. All developed methods are implemented in the statistical software package R and publicly available in the R package phenofun. Executable example code is provided as supplementary material

Особенности формирования структуры зоны термического влияния в малоуглеродистой конструкционной стали при многопроходной вневакуумной электронно-лучевой наплавке

В работе представлены результаты исследования влияния многопроходной вневакуумной электронно-лучевой наплавки порошком стали 10Р6М5+30%WC на структуру и свойства зоны термического влияния стали 20. In work results of studies of the effect multipass non-vakuum electron beam of surfacing steel powder 10Р6М5+30%WC on a structure and properties of heat affected zone steel 20

Bericht vom 5. VIVO-Workshop 2021

Der 5. VIVO-Workshop 2021 wurde bedingt durch die Corona-Pandemie als virtuelle Veranstaltung durchgeführt. In den Vorträgen konnten sich 116 registrierte Teilnehmende zu VIVO-Projekten, rechtlichen Fragen rund um Datenschutz und Dienstvereinbarungen und verschiedenen weiteren Themen rund um die Open-Source-Software VIVO, Forschungsinformationen und Forschungsinformationssysteme informieren. Eine begleitende Umfrage gibt Einsicht in technische und inhaltliche Bedarfe der Community. Als zu priorisierende Weiterentwicklung wurde die Interoperabilität mit operativen Systemen der Einrichtungen identifiziert

Bericht vom 4. VIVO-Workshop 2019

Beim 4. VIVO-Workshop 2019 an der Technischen Informationsbibliothek (TIB) wurde über das Open-Source-Forschungsinformationssystem VIVO und dessen Anwendung in verschiedenen Institutionen berichtet und diskutiert. Dabei wurden einerseits technische Lösungen vorgestellt, andererseits über Konzepte wie Profilhoheit diskutiert. Der Workshop beinhaltete eine interaktive Session, in der verschiedene Themen aus der Community diskutiert und weiterentwickelt wurden

Bericht vom 4. VIVO-Workshop 2019

Beim 4. VIVO-Workshop 2019 an der Technischen Informationsbibliothek (TIB) wurde über das Open-Source-Forschungsinformationssystem VIVO und dessen Anwendung in verschiedenen Institutionen berichtet und diskutiert. Dabei wurden einerseits technische Lösungen vorgestellt, andererseits über Konzepte wie Profilhoheit diskutiert. Der Workshop beinhaltete eine interaktive Session, in der verschiedene Themen aus der Community diskutiert und weiterentwickelt wurden

Hypergravity attenuates Reactivity in Primary Murine Astrocytes

Neuronal activity is the key modulator of nearly every aspect of behavior, affecting cognition, learning, and memory as well as motion. Hence, disturbances of the transmission of synaptic signals are the main cause of many neurological disorders. Lesions to nervous tissues are associated with phenotypic changes mediated by astrocytes becoming reactive. Reactive astrocytes form the basis of astrogliosis and glial scar formation. Astrocyte reactivity is often targeted to inhibit axon dystrophy and thus promote neuronal regeneration. Here, we aim to understand the impact of gravitational loading induced by hypergravity to potentially modify key features of astrocyte reactivity. We exposed primary murine astrocytes as a model system closely resembling the in vivo reactivity phenotype on custom-built centrifuges for cultivation as well as for live-cell imaging under hypergravity conditions in a physiological range (2g and 10g). We revealed spreading rates, migration velocities, and stellation to be diminished under 2g hypergravity. In contrast, proliferation and apoptosis rates were not affected. In particular, hypergravity attenuated reactivity induction. We observed cytoskeletal remodeling of actin filaments and microtubules under hypergravity. Hence, the reorganization of these key elements of cell structure demonstrates that fundamental mechanisms on shape and mobility of astrocytes are affected due to altered gravity conditions. In future experiments, potential target molecules for pharmacological interventions that attenuate astrocytic reactivity will be investigated. The ultimate goal is to enhance neuronal regeneration for novel therapeutic approache

Hypergravity attenuates Reactivity in Primary Murine Astrocytes

Neuronal activity is the key modulator of nearly every aspect of behavior, affecting cognition, learning and memory as well as motion. Alterations or even disruptions of the transmission of synaptic signals are the main cause of many neurological disorders. Lesions to nervous tissues are associated with phenotypic changes mediated by astrocytes becoming reactive. Reactive astrocytes form the basis of astrogliosis and glial scar formation. Astrocyte reactivity is often targeted to inhibit axon dystrophy and thus promote neuronal regeneration. Here, we use increased gravitational (mechanical) loading induced by hypergravity to identify a potential method to modify key features of astrocyte reactivity. We exposed primary murine astrocytes as a model system closely resembling the reactivity phenotype in vivo on custom-built centrifuges for cultivation as well as for livecell imaging under hypergravity conditions in a physiological range (2g and 10g). This resulted in significant changes to astrocyte morphology, behavior and reactivity phenotypes, with the ultimate goal being to enhance neuronal regeneration for novel therapeutic approaches

Model insights into energetic photoelectrons measured at Mars by MAVEN

Photoelectrons are important for heating, ionization, and airglow production in planetary atmospheres. Measured electron fluxes provide insight into the sources and sinks of energy in the Martian upper atmosphere. The Solar Wind Electron Analyzer instrument on board the MAVEN (Mars Atmosphere and Volatile EvolutioN) spacecraft measured photoelectrons including Auger electrons with 500 eV energies. A two-stream electron transport code was used to interpret the observations, including Auger electrons associated with K shell ionization of carbon, oxygen, and nitrogen. It explains the processes that control the photoelectron spectrum, such as the solar irradiance at different wavelengths, external electron fluxes from the Martian magnetosheath or tail, and the structure of the upper atmosphere (e.g., the thermal electron density). Our understanding of the complex processes related to the conversion of solar irradiances to thermal energy in the Martian ionosphere will be advanced by model comparisons with measurements of suprathermal electrons by MAVEN