968 research outputs found
Impacts drive lunar rockfalls over billions of years
No full textPast exploration missions have revealed that the lunar topography is eroded through mass wasting processes such as rockfalls and other types of landslides, similar to Earth. We have analyzed an archive of more than 2 million high-resolution images using an AI and big data-driven approach and created the first global map of 136.610 lunar rockfall events. Using this map, we show that mass wasting is primarily driven by impacts and impact-induced fracture networks. We further identify a large number of currently unknown rockfall clusters, potentially revealing regions of recent seismic activity. Our observations show that the oldest, pre-Nectarian topography still hosts rockfalls, indicating that its erosion has been active throughout the late Copernican age and likely continues today. Our findings have important implications for the estimation of the Moon’s erosional state and other airless bodies as well as for the understanding of the topographic evolution of planetary surfaces in general
Alf Nilsen-Børsskog — The Author Chosen by the Language
No full textThis article discusses Alf Nilsen-Børsskog’s four-volume series of novels Elämän jatko [Continuation of life, 2004–2015], seen as the first literary works treating the Kven culture from a native perspective. Nilsen-Børsskog’s novels are analysed as constituting a “counterstory”, a term coined in the postcolonial cultural research paradigm to refer to self-representation. The Kvens have been considered a national minority in Norway since 1999, and their language has been an official minority language since 2005. The present author scrutinizes how Nilsen-Børsskog’s work differs from previous literary descriptions of this minority, often marked by the frequent use of stereotypes of the Kven language and culture
LIBS and LA-SD-OES Analysis of Minor and Trace Elements in Steel Samples
No full textAuthor Valentin Ehrentraut, BScMasterarbeit Universität Linz 2022Arbeit nach Ablauf der Sperre auf den öffentlichen PCs in den Bibliotheken der JKU+Medizin abrufba
Discovery of a Dust Sorting Process on Boulders Near the Reiner Gamma Swirl on the Moon
No full textIn a database of lunar fractured boulders (Rüsch & Bickel, 2023, https://doi.org/10.3847/psj/acd1ef), we found boulders with reflectance features dissimilar to previously known morphologies. We performed a photo-geologic investigation and determined that the features correspond to a dust mantling on top of boulders with a unique photometric behavior. We next performed a photometric model inversion on the dust mantling using Bayesian inference sampling. Modeling indicates that the dust photometric anomaly is most likely due to a reduced opposition effect, whereas the single scattering albedo is not significantly different from that of the nearby background regolith. This implies a different structure of the dust mantling relative to the normal regolith. We identified and discussed several potential processes to explain the development of such soil. None of these mechanisms can entirely explain the multitude of observational constraints unless evoking anomalous boulder properties. Further study of these boulders can shed light on the workings of a natural dust sorting process potentially involving dust dynamics, a magnetic field, and electrostatic dust transport. The presence of these boulders appears to be limited to the Reiner K crater near the Reiner Gamma magnetic and photometric anomaly. This close spatial relationship further highlights that poorly understood processes occur in this specific region of the Moon
Thermophysical Change Detection on the Moon with the Lunar Reconnaissance Orbiter Diviner sensor
No full textThe Moon is an archive of the history of the Solar System, as it has recorded and preserved physical events that have occurred over billions of years. NASA’s Lunar Reconnaissance Orbiter (LRO) has been studying the lunar surface for more than 13 years, and its datasets contain valuable information about the evolution of the Moon. However, the vast amount and heterogeneous nature of data collected by LRO make the extraction of scientific insights very challenging - in the past most analyses relied on human review. Here, we present NEPHTHYS, an automated solution for discovering thermophysical changes on the surface using one of LRO’s largest datasets: the thermal data collected by its Diviner instrument. Specifically, NEPHTHYS is able to perform systematic, efficient, and large-scale change detection of present-day impact craters on the surface. Further work could enable more comprehensive studies of lunar surface impact flux rates and surface evolution rates, providing critical new information for future missions
LineaMapper: A deep learning-powered tool for mapping linear surface features on Europa
No full textAs discontinuities of the smooth icy surface, linear surface features might be directly or indirectly linked to Europa’s subsurface ocean. Mapping and categorising Europa’s lineaments is a means of retrieving information that could be linked to their formation history. As of today, planetary mapping is mainly conducted manually, which is tedious and subject to human bias once data sets become large. Mapping is further complicated by the heterogeneous quality and coverage of the available image data.
Here, we train LineaMapper, a convolutional neural network (Mask R-CNN), to conduct instance segmentation of the four main units of linear surface features on Europa: bands, double ridges, ridge complexes and undifferentiated lineae. LineaMapper is trained on the basis of 15 mosaics from the Galileo solid-state imager data, yielding 930 training tiles. With LineaMapper, we provide a new method that facilitates detailed mapping of lineaments in Galileo images. LineaMapper could be applied to data to be returned by the Europa Imaging System (EIS) onboard the Europa Clipper mission. We validate LineaMapper v1.0 on an independent test set. On this test set, LineaMapper shows an overall higher precision than recall. In other words, there are more non-detections of actual lineaments than there are false detections of lineaments. The model shows the most correct predictions for double ridges (highest precision), while the most complete detections happen for ridge complexes (highest recall), compared with the ground truth. In some cases, LineaMapper preserves the cross-cutting relationships. The biggest strength of LineaMapper lies in its speed and tunable output. In the future, LineaMapper can be retrained, fine tuned and applied to similar looking features, for example wrinkle ridges on Venus, ridges on other planets and moons or even dust devil tracks on Mars
Johann Siegmund Valentin Popowitsch (Janez Žiga Valentin Popovič), Vocabula Austriaca et Stiriaca 1-2 (Frankfurt am Main 2004)
No full textThe Austrian dictionary composed by the Slovenian scho-lar Janez Žiga Valentin Popovič (1705-1774) in the third quarter of the 18th century was only published in 2004, and edited by Richard Reutner, who wrote an extensive introduction to it. The dictionary comprises many language-geographical data for the German language, excellent explanations and many comparisons with much information provided regarding Popovic's mother tongue. The author broad horizon is admirable, especially with regard to the German language area and the linguistic literature of that time.Avstrijski slovar, ki ga je v tretji četrtini 18. stoletja sestavil slovenski učenjak Janez Žiga Valentin Popovič (1705-1774), je izšel šele leta 2004 v uredništvu Richarda Reutnerja, kije k njemu napisal obsežen uvod. Slovar vsebuje mnogo jezikovnogeografskih podatkov za nemščino, odlične razlage in marsikaj primerjalnega, veliko pa se najde tudi v zvezi s Popovičevo materinščino. Občudovanja vredna je avtorjeva razgledanost predvsem po nemškem jezikoslovnem prostoru in po takratni jezikoslovni literaturi
Valentin N. Volóchinov: um filósofo da ciência da linguagem
No full textThis text address the work of Russian scholar Valentin N. Vološinov, author of the book Marxism and the Philosophy of Language. The objective is to demonstrate a set of characteristics that place Vološinov as a participant in the critique of science movement, which had its epicenter in Germany, between the years 1840 and 1900. To this end, in addition to a general reflection, which recovers the meaning of the term “criticism” most present in the academic environment of the time, this text considers two points of the much mentioned – and, apparently, somewhat misunderstood – opposition of the Russian thinker to the linguistics of Ferdinand de Saussure, as this linguistics is presented in the Course in General Linguistics. Finally, by way of provocation, this text outlines a few words about the proximity between the epistemological works of Valentin N. Vološinov and Wilhelm Dilthey.Este texto aborda la obra del estudioso ruso Valentin N. Voloshinov, autor de la obra Marxismo y filosofía del lenguaje. El objetivo es demostrar un conjunto de características que sitúan a Voloshinov como participante del movimiento de crítica científica, que tuvo su epicentro en Alemania, entre los años 1840 y 1900. Para ello, además de una reflexión general, que recupera el significado del término “crítica” más presente en el ambiente académico de la época, se consideran dos puntos de la tan mencionada –y, aparentemente, algo incomprendida– oposición del pensador ruso a la lingüística de Ferdinand de Saussure, tal como se presenta esta última en el curso de lingüística general. Al final, a modo de provocación, se esbozan algunas palabras sobre la proximidad entre las obras epistemológicas de Valentin N. Voloshinov y Wilhelm Dilthey.O presente texto aborda o trabalho do estudioso russo Valentin N. Volóchinov, autor da obra Marxismo e filosofia da linguagem. O objetivo é demonstrar um conjunto de características que situam Volóchinov como um partícipe do movimento de crítica das ciências, o qual teve seu epicentro na Alemanha, entre os anos 1840 e 1900. Para isso, além de uma reflexão geral, que recupera a acepção do termo “crítica” mais presente no ambiente acadêmico da época, são considerados dois pontos da muito mencionada – e, ao que tudo indica, um tanto mal compreendido – oposição do pensador russo à linguística de Ferdinand de Saussure, tal como essa última é apresentada no Curso de linguística geral. Ao fim, a título de provocação, são esboçadas algumas palavras a respeito da proximidade entre os trabalhos epistemológicos de Valentin N. Volóchinov e Wilhelm Dilthey
Automated Discovery of Anomalous Features in Ultralarge Planetary Remote-Sensing Datasets Using Variational Autoencoders
No full textThe NASA Lunar Reconnaissance Orbiter (LRO) has returned petabytes of lunar high spatial resolution surface imagery over the past decade, impractical for humans to fully review manually. Here, we develop an automated method using a deep generative visual model that rapidly retrieves scientifically interesting examples of LRO surface imagery representing the first planetary image anomaly detector. We give quantitative experimental evidence that our method preferentially retrieves anomalous samples such as notable geological features and known human landing and spacecraft crash sites. Our method addresses a major capability gap in planetary science and presents a novel way to unlock insights hidden in ever-increasing remote-sensing data archives, with numerous applications to other science domains
Shifting patterns of fruit production in tropical forests with negative outnumbering positive trends
No full textAnalysis related to Shifting patterns of fruit production in tropical
forests with negative outnumbering positive trends from Hacket-Pain et al.
Code generated by Journé Valentin.
For details please check the README (Wiki) and the main study
corresponding author: Andrew Hacket-Pain; [email protected]
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