bluuebunny/crossref_metadata_2025 huggingface dataset:
ІНФОРМАТИЗАЦІЯ ОЦІНЮВАННЯ У ПРОЦЕСІ ФІЗИЧНОГО ВИХОВАННЯ
Authors: Кіндрат Павло , Сяська Наталія , Кіндрат Вадим , Кіндрат Наталія
Published: March 2021

Впровадження інформаційних технологій здійснюється в різних напрямках педагогічної діяльності і дозволяє адаптувати навчальну діяльність до потреб сучасної школи. Зокрема шляхом підвищення якості оцінювання фізичної підготовленості та розвитку учнів. Розглянута модель інформаційної системи покликана інтегрувати різноспрямовані підходи до оцінювання та надати учителю фізичного виховання надійний інструмент допомоги у прийнятті рішень щодо здійснення своєї професійної діяльності.
РОЗВИТОК ДОСЛІДНИЦЬКОЇ АКТИВНОСТІ ДІТЕЙ СТАРШОГО ДОШКІЛЬНОГО ВІКУ В ПРОЦЕСІ ЕКСПЕРИМЕНТУВАННЯ
Authors: Котелянець Наталка
Published: March 2021

У статті розглядаються теоретичні аспекти розвитку дослідницької активності дітей старшого дошкільного віку. На основі аналізу досліджень уточнено сутність поняття «дослідницька активність»; визначена логіка розвитку дослідницької активності в дошкільному віці. Встановлено, що умовою розвитку дослідницької активності дитини є її суб’єктна позиція, яка проявляється в умінні висунути і реалізувати гіпотезу вирішення проблеми в умовах різноманітної пошукової діяльності та експериментування. Акцентовано увагу на тому, що дослідницька активність як цілісне утворення являє собою єдність трьох компонентів: мотиваційного, змістового, операційного.
ОРГАНІЗАЦІЯ ПРОВЕДЕННЯ ІСПИТІВ З ФІЗІОЛОГІЇ ТА БІОЛОГІЧНОЇ І БІООРГАНІЧНОЇ ХІМІЇ В ЧЕРКАСЬКІЙ МЕДИЧНІЙ АКАДЕМІЇ В УМОВАХ ДИСТАНЦІЙНОГО НАВЧАННЯ
Authors: Радзієвська Ірина , Степанова Галина
Published: March 2021

Аналіз досвіду викладачів Черкаської медичної академії з приймання іспитів з предметів «Фізіологія» та «Біологічна і біоорганічна хімія» дозволяє виокремити як позитивні сторони такої форми контролю знань (урізноманітнення й осучаснення навчального процесу, усунення перешкод для будь-яких учасників освітнього процесу тощо), так і проблемні місця нових дистанційних освітніх технологій (необхідність залучення сучасної комп’ютерної техніки, програмного забезпечення й швидкого Інтернету, проблеми з передачею студентам необхідних для іспиту інформаційних матеріалів у належній якості, брак психологічного контакту викладача зі студентом «очі в очі», складність запобігання академічній недоброчесності студентів і списуванню, додаткові витрати часу на розробку матеріалів для дистанційного оцінювання знань студентів).
ГЕНЕАЛОГИЯ ЦИФРОВОГО БУДДИЗМА
Authors: Зарипова Антонина
Published: March 2021

Статья посвящена истории Буддизма в цифровом (DIGITAL) мире. Большинство религий проникли в интернет, в том числе и буддизм и используют новые технологии в маркетинговых целях. Все больше людей активно используют социальные сети и интернет для поиска и передачи и распространения религиозной информации.
КОРПОРАТИВНАЯ (СОЦИАЛЬНАЯ) ОТВЕТСТВЕННОСТЬ СУБЪЕКТОВ ПРЕДПРИНИМАТЕЛЬСКОЙ ДЕЯТЕЛЬНОСТИ
Authors: Аббаслы Айсель
Published: March 2021

В представленной статье рассмотрена корпоративная (социальная) ответственность субъектов предпринимательской деятельности. Автор отмечает, что усовершенствование механизма нормативно-правового регулирования, нормативное закрепление обязанности социальной отчетности крупных предприятий и согласование корпоративной ответственности данных предприятий с социальной политикой государства было бы целесообразным с точки зрения полного и рационального решения задач социального характера в Азербайджане, как показывает опыт зарубежных стран.
REDUCTION OF BONE MINERAL DENSITY IN WOMEN OF REPRODUCTIVE AGE, DESCENDANTS OF THOSE IRRADIATED AS A RESULT OF NUCLEAR TESTS
Authors: Ryspaeva Zh. , Tanysheva G. , Ahmedzianova Z. , Kapenova A.
Published: March 2021

Aim of research: To determine the frequency and degree of decrease in bone mineral density in women of reproductive age who are descendants of persons exposed to radiation as a result of nuclear tests at the Semipalatinsk test site. The study included 383 women, descendants of non-irradiated and irradiated II and III generations in the female line. The parameters of bone mineral density in 2 age groups (II generation - 1962-1987 year of birth and III generation – 1988-1996 year of birth) were studied by ultrasound densitometry. It was revealed that women of reproductive age with irradiated ancestors of the second and third generation, who lived in areas of maximum and extreme radiation risk, had a relative decrease in bone mineral density, which was statistically significant in relation to the descendants of persons who were not exposed to chronic anthropogenic sources of ionizing radiation. There were statistically significant relationship between exposure ancestors II and III generation and indicators BMD their offspring, women of reproductive age. It is possible to predict the rapid development of involutional osteoporosis in women-descendants of irradiated patients in the ІІ and ІІІ generation.
ВМІСТ ВАЖКИХ МЕТАЛІВ У ВОДІ РОЗПОДІЛЬЧОГО КАНАЛУ Р-1 КАХОВСЬКОЇ ЗРОШУВАЛЬНОЇ СИСТЕМИ
Authors: Хохлова Людмила , Лукашов Дмитро
Published: March 2021

У статті наведено результати дослідження вмісту важких металів у воді розподільчого каналу Р-1 Каховської зрошувальної системи на території Херсонської області (Україна) у літній період 2019 року. Встановлено, що середня концентрація металів у воді зменшується у такому порядку: Zn>Cu>Fe>Ni>Cr>Co>Pb>Cd. У всіх зразках концентрація Pb та Cd була нижче межі виявлення аналітичного методу. Спостерігається тенденція до збільшення концентрації важких металів у воді вниз за течією гідромеліоративного об’єкту.
ФИЗИЧЕСКОЕ ОБЪЯСНЕНИЕ ВОЗНИКНОВЕНИЯ ЭЛЕКТРОДВИЖУЩЕЙ СИЛЫ ПРИ ОДНОРОДНОМ НАГРЕВЕ ИЗОТИПНОГО МИКРОЗЕРНИСТОГО КРЕМНИЕВОГО ПРЕОБРАЗОВАТЕЛЯ ТЕПЛОВОЙ ЭНЕРГИИ
Authors: Кадыров Абдулахат , Касымов Далер
Published: March 2021

Предлагается прямое преобразование нефотоактивной составляющей солнечного излучения в электричество. Созданием в вторичном литом поликристаллическом кремнии (ВЛПК) условий проявления примесного тепловольтаического эффекта достигается генерация носителей тока за счет поглощения субзонных фотонов. Показано, что наблюдаемые явления обусловлены синергетическими процессами, происходящие в полупроводнике.
ПЕДАГОГІЧНА ТЕХНОЛОГІЯ ФОРМУВАННЯ ГОТОВНОСТІ МАЙБУТНІХ ВЧИТЕЛІВ ФІЗИЧНОЇ КУЛЬТУРИ ДО ІННОВАЦІЙНОЇ ДІЯЛЬНОСТІ
Authors: Веселовський А. , Чепелюк А. , Зварич Г.
Published: March 2021

У даній статті розглядається проблема формування готовності майбутніх учителів фізичної культури до інноваційної діяльності. Мета статті полягає в обґрунтуванні педагогічної технології та аналізі її ефективності на основі критеріїв і показників готовності до інноваційної діяльності. В основу розробки педагогічної технології формування готовності до інноваційної діяльності покладена концепція цілеспрямованого розвитку психомоторних здібностей В. Озерова. Автор дає узагальнену характеристику технології, яка складається з мотиваційно-рефлексивного, педагогічного, тренерського, рекреаційно-творчого компонентів. У статті представлені результати дослідження, які підтверджують ефективність розробленої експериментальної технології.
Understanding the relationship between environmental policies and deforestation activities in the Paraguayan Chaco
Authors: Garcia Calabrese Monserrat , Salinas Romero Shirley , Cassacia Ibarrola Chynthya , Morinigo Luis , Alvarenga Magali , Da Ponte Emmanuel
Published: March 2021

Over the past 40 years, Paraguay has lost the majority of its natural forest cover, thus becoming one of the countries with the highest deforestation rates in the world. Uninterrupted deforestation practices in the Paraguayan Chaco between 1987 and 2012 resulted in the loss of 27% of its original cover, accounting for almost 44,000 km2 of forested areas depleted. The rapid expansion of the agricultural frontier, cattle ranching, and illegal logging has converted the last forest remnants into isolated patches, thus endangering their continuity and biodiversity within them. In response to these events, the Paraguayan government has implemented numerous environmental programs and regulations to amend the damage that had happened in the past. Although governmental agencies claim a reduction in deforestation activities in the region, proper scientific environmental data that analyze the long-term effect of such regulations/programs remain scarce. Within this context, the present research analyzes the impact of local governments on changes occurred in Paraguayan Chaco forest between the years 1986 and 2020. Remote sensing data acquired from Landsat 4, 5, 7 and 8 images were used to derive the extent of the forest cover and deforestation rates over 34 years. Dynamics of the forest cover was correlated with each of the 10 government terms within the timeframe of the study. By analyzing the forest cover data during and after each term (around five years per government term), we sought to understand the influence of local policies on deforestation activities in the eco-region, aiming to identify social, political, and institutional drivers of change. A comprehensive assessment of creation and effectivities of protected areas, land concession to indigenous communities, and development/implementation of local policies and environmental laws are part of this study. Preliminary results show a significative difference on forest cover loss among governments terms ranging between 1% (2,385 km2) and 9% (14,422 km2). The lack of clear regulations, sound law enforcement, financial support, and inappropriate governance were initially identified as key drivers of change. The use of multi-temporal information was demonstrated to be a key component for designing, supporting, and monitoring conservation strategies and policies. It is crucial to consider not only the outlook of laws and policies aiming to halt deforestation activities but their actual influence on the behavior of natural resources over time.
Comparing impact effects of common storms and Medicanes along the coast of Southeastern Sicily
Authors: Scardino Giovanni , Scicchitano Giovanni , Rizzo Angela , Monaco Carmelo , Piscitelli Arcangelo , Milella Maurilio , Francesco De Giosa , Mastronuzzi Giuseppe
Published: March 2021

The coastal vulnerability along the Mediterranean coasts is increasing, especially in response to the occurrence of tropical-like events, known as Medicanes, which have become more intense than in the past. A peculiar case was the impact of Medicane Zorbas occurred in September 2018 along the coasts of Southeastern Sicily, where it caused inland flooding and damages to the socio-economic activities. We reconstructed Zorbas effects through post-event geomorphological surveys, interviews to direct witness and analyses of video recorded by surveillance systems or found in the social media. These data allowed to assess the flooding extent on seven coastal sectors located between Thapsos Peninsula and Marzamemi. Flooding caused by Zorbas appears to be greater than those surveyed after the main seasonal storms occurred in the areas from 2015 to 2019, but comparable with the flooding generated by Medicane Qendresa that impacted the southeastern Sicily in 2014. Waves propagation modelling was performed through Delft 3D for the main marine extreme events occurred in the area since 2005, and analyses of data recorded by tide gauge of Catania and Porto Palo di Capo Passero and Malta since 2008 let us to hypothesize that Medicanes generate greater flooding than seasonal storms because they can induce higher and longer surge along the coastline. Collected data indicate that surge generated by Zorbas reached a maximum value between about 0.8 m and 1.2 m above mean sea level (msl) along the coast of southeastern Sicily. Results highlighted the need to better evaluate the coastal hazard related to the propagation of Medicanes, especially in the context of future climate change, when these events could be characterized by a longer duration and a greater intensity than the present, such to cause greater flooding and damage to the coastal areas.

 

Keywords: coastal flooding; storm wave; storm surge; Medicane; vulnerability.
Greenland's glacier tidal response and ice sheet motion  
Authors: Christmann Julia , Helm Veit , Khan Shfaqat Abbas , Kleiner Thomas , Müller Ralf , Morlighem Mathieu , Neckel Niklas , Rückamp Martin , Steinhage Daniel , Zeising Ole , Humbert Angelika
Published: March 2021

The Greenland ice sheet is the largest contributor to global sea-level rise. Large uncertainties remain in sea level rise projections due to limited insights in the dynamics of outlet glaciers in Greenland. Nioghalvfjerdsbræ (79°NG) is an outlet glacier of the Northeast Greenland Ice Stream (NEGIS), which holds 1.1 m sea-level equivalent of ice. 
While critical progress has been made in ice sheet modelling, the motion of fast-moving ice streams and their interactions with ocean tides remain poorly understood. We combine GPS observations and two-dimensional numerical modelling to show that tides alter lubrication of the glacier as far as 15 km inland. Modelling these systems is highly complex due to the need for an appropriate material model and the interaction of different components of the physical system. We associate a viscoelastic material with subglacial hydrology and get friction parameters by solving an inverse problem. Steep basal topography enhances creep by 14% locally, whereas in the majority of the fast-moving part of NEGIS the ratio of creep to sliding is below 2%. Based on the viscoelastic material model, it is possible to distinguish between elastic and viscous strains that sum up to the total strain. The elastic strain contribution in the considered cross-section is up to 34%, independent of any tidal forcing. Elastic strain contributes significantly to deformation in fast-moving outlet glaciers and appears to coincide with crevasses representing the solid nature of ice. Including sliding and elastic deformation in ice sheet models to represent recent accelerations of outlet glaciers is an important step forward in reducing uncertainties of Greenland’s contribution to future sea-level rise.
Estimating the air-sea gas transfer velocity from a statistical reconstruction of ocean turbulence observations
Authors: Carella Giulia , Esters Leonie , Galí Tàpias Martí , Gomez Gonzalez Carlos , Bernardello Raffaele
Published: March 2021

Although the air-sea gas transfer velocity k is usually parameterized with wind speed, the so-called small-eddy model suggests a relationship between k and the ocean surface turbulence in the form of the dissipation rate of turbulent kinetic energy ε. However, available observations of ε from oceanographic cruises are spatially and temporally sparse. In this study, we use a Gaussian Process (GP) model to investigate the relationship between the observed profiles of ε and co-located atmospheric and oceanic fields from the ERA5 reanalysis. The model is then used to construct monthly maps of ε and to estimate the climatological air-sea gas transfer velocity from existing parametrizations. As an independent  validation,  the same model is also trained on EC-Earth3 outputs with the objective of reproducing the temporal and spatial patterns of turbulence kinetic energy as simulated by EC-Earth3. The ability to predict ε is instrumental to achieve better estimates of air-sea gas exchange that take into account multiple sources of upper ocean turbulence beyond wind stress.
The transitions from mildly explosive to caldera-forming eruptions at Colli Albani volcano (Italy)
Authors: Ágreda López Mónica , Caricchi Luca , Jorgenson Corin , Musu Alessandro , Giordano Guido
Published: March 2021

The Colli Albani volcano is an ultrapotassic caldera complex located 30 km to the SE of Rome and has displayed a wide range of eruptive behaviors, ranging from effusive activity to highly explosive and large volume eruptions (up to 63 km3 dense rock equivalent per eruption) despite its mafic nature.

We combine physical volcanology, petrology, and geochemistry to focus on the mildly explosive to effusive products of two sections (Tuscolo and Artemisio) which are located on opposite sides of the main caldera and stratigraphically between the last large ignimbrite, Villa Senni. The target of this study is to identify the processes responsible for the transition from the smaller explosions to the larger caldera-forming ignimbrite eruptions, and eventually trace how the magmatic system rebuilds in the interim.

Whole rock analyses, mineral chemistry, and petrography of fall deposits from both field localities are compared with an existing dataset for the Villa Senni ignimbrites. We will use unsupervised and supervised machine learning approaches to identify similarities and differences between large caldera-forming eruptions and mild-explosive to effusive activity and identify the processes modulating the transition between these two behaviours.
Observed Denmark Strait Overflow Cyclones around Greenland
Authors: Zou Sijia , Bower Amy , Furey Heather , Pickart Robert , Houpert Loïc , Holliday N. Penny
Published: March 2021

Abundant cyclonic eddies are observed to travel along the Deep Western Boundary Current around Greenland by Lagrangian floats, hydrographic stations and moorings. Most of the cyclones have intensified rotations below the surface (700-1000 dbar), with maximum azimuthal velocities of ~30 cm/s at radii of ~10 km. The swift rotation and small radius lead to a relatively large Rossby number (~0.4), suggesting important contributions from the ageostrophic terms. The subsurface rotational core is also characterized with a local (both vertically and horizontally) potential vorticity (PV) maximum, which is associated with the pinching of isopycnals towards the mid-depths (i.e. high stratification). The PV structure suggests the origin of the cyclone as the Denmark Strait Overflow Cyclone. The latter is known to be formed by vortex stretching southwest of the Denmark Strait, where outflow waters with high PV from the sill descends the continental slope into the low PV Irminger Sea. Finally, we show that these cyclones can influence the boundary currents around Greenland by introducing property anomalies that originate from the Denmark Strait.
Radiation belt electron acceleration during periods of low plasma density
Authors: Allison Hayley , Shprits Yuri , Zhelavskaya Irina , Wang Dedong , Smirnov Artem
Published: March 2021

Electrons in the Van Allen radiation belts can have energies in excess of 7 MeV. We present a unique way of analyzing phase space density data which demonstrates that local acceleration is capable of heating electrons up to 7 MeV. The Van Allen Probes mission not only provided unique measurements of ultra-relativistic radiation belt electrons, but also simultaneous observations of plasma waves that allowed for the routine inference of total plasma number density. Based on long-term observations, we show that the underlying plasma density has a controlling effect over local acceleration to ultra-relativistic energies, which occurs only when the plasma number density drops down to very low values (~10 cm-3). The VERB-2D model is used to simulate ultra-relativistic electron acceleration during an event which exhibits an extreme cold plasma depletion. The results show that a reduced electron plasma density allows chorus waves to efficiently resonate with electrons up to ultra-relativistic energies, producing enhancements from 100s of keV up to >7 MeV via local diffusive acceleration. We analyse statistically the observed chorus wave power during ultra-relativistic enhancement events, considering the contribution from both upper and lower band chorus waves. The PINE density model allows for the investigation of global magnetospheric density changes. We analyze the how the global cold plasma density changes during ultra-relativistic enhancement events and compare to in-situ point measurements of the plasma density.
An analysis of Italian damage data to economic activities
Authors: Galliani Marta , Carisi Francesca , Domeneghetti Alessio , Menduni Giovanni , Molinari Daniela , Sterlacchini Simone , Zazzeri Marco , Ballio Francesco
Published: March 2021

The study of flood impacts on the different sectors that compose the built environment and the society is crucial to implement actions of prevention, mitigation, and cautious planning. In such a context, the sector of businesses assumes a critical role, both for its importance for the wellbeing of the society and because of the high losses it suffers in case of inundations. Nevertheless, flood damage modelling to businesses is still a challenging task: the large number of different commercial activities, their specific geographical and economic contexts and the few observed damage data are just some of the reasons for that. In Italy, for example, a shared methodology to assess damage to enterprises is not present; building knowledge about types and dimensions of impacts of flood events to economic activities is then even more impelling. This contribution presents the analysis of about a thousand observed damage records regarding industrial and commercial activities, collected by four research groups after different flood events in Italy: the inundation occurred in the town of Lodi (Lombardia Region) in 2002, the one in Sardegna Region in 2013, and the floods caused in the Emilia-Romagna Region by Secchia (2014) and Enza (2017) Rivers. Data retrieved from the local and regional authorities responsible for damage compensation present different levels of detail and aggregation, according to the case study investigated. In all cases, they refer to the direct damage only and, for each case study, they have been first organised according to the activity types (e.g. trade, manufacturing, construction, finance) and per affected components: i.e. structure, equipment and stock. Data analysis has been led by some questions, we identified as key to start developing knowledge for damage modelling:  are there similarities in the different case studies? Which are the more affected business sectors in case of flood? Which component suffers the highest damage among structure, equipment, and stock? Is there an empirical trend of damage with hazard parameters? Results were first compared with the socio-economic context of the affected area, to have a first confirmation of data quality and reliability; then, the analysis focused on searching information and relationships between damage and activity type, activity dimension and water level. Results support the identification of the more vulnerable elements within the business sector, orienting modellers’ and decision-makers’ choices.
Spatial analytics of self-organized vegetation pattern in semi-arid regions: an example on tiger-bush patterns in Sudan
Authors: Hinz Christoph , Nengsuwan Konlavach , Cavieds-Voullieme Daniel
Published: March 2021

The concept of local-scale interactions of spatially periodic vegetation patterns are well known in arid and semi-arid regions. The vegetation patterns are easily observable from aerial and satellite photography. Additionally, various mathematical models have been developed to reproduce the patterns observed in nature, aimed towards understanding the driving factors leading to pattern properties. Several studies exist attempting to analyse spatial properties of these patterns, their spatial distribution and their relationship to  topography and climate. However, there are limitations in how these studies provide spatially-distributed statistics, and on the specifics of vegetation patch and band geometries, making it difficult to compare to model predictions. 

This study proposes  a new workflow (implemented in R) to measure geometric  characteristics of vegetation bands and patches. We use high-resolution satellite imagery as the base dataset. Color filters are used to binarise and identify individual patches/bands of arbitrary irregular shapes. We then compute different geometrical properties, such as  patch-size, separation between them, orientation, among others. Additionally, the principal axes of each patch/band are identified, and used to measure characteristic lengths and widths, for which statistics are then computed, and can be represented in spatial subdomains to allow for spatial analysis at different scales. The strategy can also be easily applied to modelling results, thus facilitating comparison, and the algorithm is flexible enough to yield different forms of patterns and spatial extent.

As a test case, we apply this workflow to a study site (11.05 N, 28.35 E) in Kordofan, south Sudan (a region previously reported and documented in the literature), using Google Earth Imagery as input. For this domain (3500 x 1400 m), the  results show that the length of the patches has a strong positive correlation with their width. Additionally, the length and the average nearest neighbor distance displayed a small positive correlation to the elevation. Using the available ALOS topography, the results also confirm that that 92% of the bands in our study area are oriented perpendicularly to the slope direction, as is expected from these systems. 

This test is a first step into applying this workflow to a larger extend within Kordofan and other regions known to exhibit vegetation bands (tiger bush in wester Africa, Australia, Nevada) and perform extensive geometric and spatial analysis of the bands, as well as simulated banded systems obtained from numerical models.

Keywords: Vegetation patterns, Self-organization, Tiger-bush, Geometric analysis, Oriented direction
Impacts and solutions associated with glacier-driven river toxicity in the Cordillera Blanca, Peru
Authors: Macdonald Moya , Wadham Jemma , La Matta Romero Fiorella , Hawkings Jon , Willems Bram , Loayza-Muro Raul
Published: March 2021

Approximately 70% of the world’s tropical glaciers are found in Peru, with 40% of these in the Cordillera Blanca (CB). Here, glaciers are an important source of meltwater to downstream people (~0.25 million) and ecosystems, supporting 40% of streamflow in the dry season. However, the CB has experienced high levels of glacier retreat and mass loss in recent decades, which has influenced the quantity and quality of water supply. During this time, some meltwater-fed rivers have become ‘toxic’, characterised by low pH and high metal concentrations. This toxicity has been linked to exposure of sulphide- and metal-rich rock types as glaciers retreat, and has implications for clean water supply (SDG 6), subsistence farming (contributing to SDG1 and 2), and freshwater biodiversity (SDG 15). Here, we present a comprehensive spatial analysis of water quality in the CB to understand the key drivers of worsening water quality and to predict which catchments may be vulnerable in the future. We sampled 18 glacierised catchments in the CB for geochemical and biological parameters during the dry and wet seasons. River pH ranged from 2.5 to 8.3, with two catchments highly acidic (~pH 2.5-3.8). The concentrations of several riverine metal species (including manganese, nickel, copper and a suite of rare-earth elements) were strongly negatively correlated with pH in the catchments. Additionally, most of the 40 metals analysed in rivers with low pH were present in a truly dissolved phase (>90% of 0.45 µm filtered concentrations were <0.02 µm), indicating high potential bioavailability and biotoxicity. Indeed, shifts in community composition of benthic macroinvertebrates indicated a replacement of sensitive benthic macroinvertebrate taxa (Limnephilidae, Hyaleliidae) in pristine rivers by more tolerant taxa (Chironomidae) in acidic rivers. We suggest that metal leaching and altitude may be important factors influencing diversity, richness and abundance of benthic macroinvertebrate communities. Here, we synthesize data on water quality and glacier retreat, offer predictions of future river toxicity and introduce a novel citizen-science, green-infrastructure initiative being developed to combat water quality degradation in the region.
Cretaceous Black Shales in the Pacific: The Equatorial Position Hypothesis
Authors: Bouwmeester Max J. , Boschman Lydian , Berends Nienke , Owens Jeremy D. , Gill Ben C. , Trabucho Alexandre João P.
Published: March 2021

Although anoxia is rare in modern oceans, the marine stratigraphic record is punctuated by sedimentary and geochemical evidence for episodes of widespread oceanic anoxia. The last time in Earth history that a large volume of the ocean became anoxic was in the middle Cretaceous: black organic-carbon-rich muds were repeatedly preserved on the deep seafloor during oceanic anoxic events (OAEs).

Sedimentary and geochemical evidence for oceanic anoxia during OAEs comes mainly from the Atlantic and Tethys Oceans. Data from the Pacific Ocean, which was the largest ocean basin in the middle Cretaceous, is scarce and equivocal. Based on black shales deposited at depths of about 500–1500 m on seamounts, Monteiro et al. (2012) have suggested that at least 50 vol% of the ocean was anoxic at the climax of Cretaceous oceanic anoxia during the late Cenomanian. They also included a single black shale at DSDP Site 585 in the Mariana Basin as evidence for anoxia in the deep Pacific. We will show, however, that this is a mud turbidite reworked from shallower water.

For this study, we reviewed all available data and publications from scientific drilling that recovered Cretaceous sediments in the Pacific Ocean. The little available Cretaceous record from the Pacific consists mainly of well-oxidized sediments. The exceptions are black shales that occur at depths of about 500–1500 m on seamounts. Takashima et al. (2011) have shown that the Asian and North American continental margins of the Pacific were indeed oxic for most of the late Cenomanian OAE. 

We used a new paleomagnetic reconstruction of the Pacific plate back to 150 Ma to show that all investigated Cretaceous organic-carbon-rich sediments in the Pacific Ocean were deposited while the site was located in the Equatorial Divergence Zone (10°S to 10°N). We therefore argue that organic matter deposition in the Pacific Ocean might not have been directly related to OAEs, but rather be associated with the passage of seamounts beneath the equatorial belt of high productivity.

Several authors have challenged suggestions that OAEs were characterized by globally pervasive anoxic deep water and pointed to the difficulty in sustaining whole-ocean anoxia, even in warm oceans. We agree and our results show that oceanic anoxia in the Pacific is a local phenomenon superposed on a global trend of expanded oxygen minima in the ocean.
The structure of signal space:  a case study of direct mapping between seismic waveforms and event distribution
Authors: Harris David , Dodge Douglas
Published: March 2021

Under special circumstances, waveform observations of seismic events related by a common, spatially-distributed source process exhibit a geometric architecture that is a distorted image of event distribution in the source region.  We describe a prescription for visualizing this signal space image and use a machine-learning algorithm, Isomap, and an algorithm due to Menke to invert collections of waveforms directly for relative event location.  We illustrate concepts and methods with well-characterized induced seismicity at a coal mine in the U.S. state of Utah observed by two local seismic instruments, and with synthetics.  We anticipate application of these methods to repetitive volcanic seismicity, icequakes and induced seismicity.

This is Lawrence Livermore National Laboratory contribution LLNL-ABS-818445.
Revealing the spatial pattern of subsurface soil salinity over the Argentinean Dry Chaco
Authors: Maertens Michiel , Vanacker Veerle , De Lannoy Gabriëlle , Vincent Frederike , Giménez Raul , Gasparri Ignacio
Published: March 2021

The South-American Dry Chaco is a unique ecoregion as it is one of the largest sedimentary plains in the world hosting the planet’s largest dry forest. The 787.000 km² region covers parts of Argentina, Paraguay, and Bolivia and is characterized by a negative climatic water balance as a consequence of limited rainfall inputs (800 mm/year) and high temperatures (21°C). In combination with the region’s extreme flat topography (slopes < 0.1%) and shallow groundwater tables, saline soils are expected in substantial parts of the region. In addition, it is expected that large-scale deforestation processes disrupt the hydrological cycle resulting in rising groundwater tables and further increase the risk for soil salinization.

In this study, we identified the regional-scale patterns of subsurface soil salinity in the Dry Chaco.  Field data were obtained during a two-month field campaign in the dry season of 2019. A total of 492 surface- and 142 subsurface-samples were collected along East-West transects to determine soil electric conductivity, pH, bulk density and humidity. Spatial regression techniques were used to reveal the topographic and ecohydrological variables that are associated with subsurface soil salinity over the Dry Chaco. The hydrological information was obtained from a state-of-the-art land surface model with an improved set of satellite-derived vegetation and land cover parameters.

In the presentation, we will present a subsurface soil salinity map for a part of the Argentinean Dry Chaco and provide relevant insights into the driving mechanisms behind it.
Numerical modelling of quartz-biotite aggregates: Insights on strain weakening and two-phase flow laws
Authors: Rast Markus , Ruh Jonas
Published: March 2021

Strain weakening is a prerequisite for localization of strain and therefore crucial for the understanding of shear zone evolution. In the context of progressive deformation of multi-phase aggregates, it is unclear whether the change in geometry and orientation of the involved phases leads to structural or geometric strain weakening and thus may control strain localization. Consequently, the question arises how the ductile flow of two-phase rocks can be described or determined. To contribute to a better understanding of the knowledge gaps outlined above, two-dimensional numerical shear experiments of quartz-biotite aggregates were conducted at varying temperatures, background strain rates and fluid pressure ratios. Textural variations after a shear strain of γ ≈ 10 appear to be dependent on the viscosity contrast between the minerals involved. To estimate whether a numerical experiment is undergoing strain weakening or strain hardening (or both), the temporal evolution of the mean second invariant of the deviatoric stress tensor was tracked. The results suggest that strain weakening occurs if biotite-inclusions are distinctly isolated and that it is more effective under conditions with larger viscosity contrasts between matrix and inclusions. However, the stress drops in numerical experiments with purely structural / textural strain weakening are rather low (−1.1 to −6.4%) compared to other strain weakening processes. It appears that phase rearrangement and change in phase geometry with evolving strain is of minor importance for the occurrence of strain weakening. Based on the numerical experiments and assuming a power-law relationship between stress and strain, the flow-law parameters of quartz-biotite aggregates with different biotite contents were determined. The results are in the range of existing experimental and analytical mixed-aggregates flow-laws. However, the variations between the different flow-laws show that further research is required, for which numerical models as used in the present study could serve as basis.
Shear and compressive wave data acquisition using multicomponent vibrating source and landstreamer
Authors: Pugin Andre , Dietiker Barbara , Brewer Kevin , Cartwright Timothy
Published: March 2021

In the vicinity of Ottawa, Ontario, Canada, we have recorded many multicomponent seismic data sets using an in-house multicom­ponent vibrator source named Microvibe and a landstreamer receiver array with 48 3-C 28-Hz geophones at 0.75-m intervals. The receiver spread length was 35.25 m, and the near-offset was 1.50 m. We used one, two or three source and three receiver orientations — vertical (V), inline-horizontal (H1), and transverse-horizontal (H2). We identified several reflection wave modes in the field records — PP, PS, SP, and SS, in addition to refracted waves, and Rayleigh-mode and Love-mode surface waves. We computed the semblance spectra of the selected shot records and ascertained the wave modes based on the semblance peaks. We then performed CMP stacking of each of the 9-C data sets using the PP and SS stacking velocities to compute PP and SS reflection profiles.

Despite the fact that any source type can generate any combination of wave modes — PP, PS, SP, and SS, partitioning of the source energy depends on the source orientation and VP/VS ratio. Our examples demonstrate that the most prominent PP reflection energy is recorded by the VV source-receiver orientation, whereas the most prominent SS reflection energy is recorded by the H2H2 source-receiver orientation with possibility to obtain decent shear wave near surface data in all other vibrating and receiving directions.

Pugin, Andre and Yilmaz, Öz, 2019. Optimum source-receiver orientations to capture PP, PS, SP, and SS reflected wave modes. The Leading Edge, vol. 38/1, p. 45-52. https://doi.org/10.1190/tle38010045.1
Estimating the global geomorphological importance of ants in the Anthropocene
Authors: Viles Heather , Goudie Andrew , Goudie Alice
Published: March 2021

Ants are active, numerous and widespread across most landscapes on Earth. They are known to be geomorphologically important, through a range of activities (such as production of galleries and mounds) by which they move and store sediment both above and below ground. They also co-exist and interact with a wide range of other geomorphologically-active organisms, sometimes resulting in complex influences on the landscape (as ant mounds can influence soils and plant biodiversity, for example). Human impacts in the Anthropocene are having direct and indirect impacts on the geomorphological importance of ants – through species invasions, climate change etc. A geolocated database of over 100 studies, covering more than 60 ant species, carried out in Europe, Africa, South America, southern Africa, USA and Australia, is used to produce some estimates of the global impacts of ants within the Anthropocene, including a first order estimate of 7.5 – 10 Gt sediment moved per year by ants across the land surface.
Particle-In-Cell simulations of resonant interactions between whistler waves and electrons in the near-Sun solar wind: scattering of the strahl into the halo and heat flux regulation.
Authors: Micera Alfredo , Zhukov Andrei , López Rodrigo A. , Innocenti Maria Elena , Lazar Marian , Boella Elisabetta , Lapenta Giovanni
Published: March 2021

Electron velocity distribution functions, initially composed of core and strahl populations as typically encountered in the near-Sun solar wind and as recently observed by Parker Solar Probe, have been modeled via fully kinetic Particle-In-Cell simulations. It has been demonstrated that, as a consequence of the evolution of the electron velocity distribution function, two branches of the whistler heat flux instability can be excited, which can drive whistler waves propagating in the direction parallel or oblique to the background magnetic field. First, the strahl undergoes pitch-angle scattering with oblique whistler waves, which provokes the reduction of the strahl drift velocity and the simultaneous broadening of its pitch angle distribution. Moreover, the interaction with the oblique whistler waves results in the scattering towards higher perpendicular velocities of resonant strahl electrons and in the appearance of a suprathermal halo population which, at higher energies, deviates from the Maxwellian distribution. Later on, the excited whistler waves shift towards smaller angles of propagation and secondary scattering processes with quasi-parallel whistler waves lead to a redistribution of the scattered particles into a more symmetric halo. All processes are accompanied by a significant decrease of the heat flux carried by the strahl population along the magnetic field direction, although the strongest heat flux rate decrease is simultaneous with the propagation of the oblique whistler waves.
Melting and dynamic pressure: coupling of reactions, heat transfer and deformation
Authors: Schmalholz Stefan Markus , Moulas Evangelos , Podladchikov Yuri
Published: March 2021

Melting is a major process of plate tectonics, affecting divergent and convergent plate boundaries. Melting of rock is also a typical example of a coupled geological process, in which the associated transformation affects the heat transfer via the latent heat of fusion and the rock deformation via the volume change. However, petrological studies on melting usually focus on chemical aspects, such as differentiation of involved components, thermal studies usually focus only on the impact of latent heat on heat transfer, such as done in the classical Stefan problem of solidification. Similarly, studies focusing on lithosphere and mantle deformation usually only consider the impact on the effective viscosity, such as weakening due to partial melting, or the impact on buoyancy due to density changes. Many studies do, therefore, not consider coupling of melting, heat transfer and rock deformation. Indeed, a common assumption is that rock pressure, or mean stress, remains lithostatic during melting. While this assumption is attractive due to its simplicity, it is against the common knowledge derived from physical experiments and the well-established mechanical theories. Furthermore, theoretical models of melt migration would not work if pressure is everywhere lithostatic, or hydrostatic, because melt migration is driven by local deviations from the static stress state.

Here, we present simple mathematical models based on the fundamental laws of physics and thermodynamics (e.g. conservation of mass, momentum and energy) to study the fundamental coupling of melting, heat transfer and rock deformation, and to quantify dynamic pressure variations due to melting. We show both analytical and numerical solutions for these models. We discuss applications of these solutions to experiments and geological observations and estimate magnitudes of dynamic pressure resulting from melting under natural conditions.
Benchmark of predictive simulations of block trajectories using field experiments 
Authors: Bourrier Franck ,   Members of task A.3.1 of C2ROP project
Published: March 2021

A comparative analysis between block propagation experiments and predictive simulations of block trajectories was conducted to evaluate the predictive capacities of block propagation analyses. Approximately one hundred blocks were released on two propagation paths with topographical discontinuities and configurations promoting block rolling. The block propagation was analysed at specific locations of the paths, called evaluation screens. A significant variability of the block velocities was measured at the screens and bimodal distributions of the velocities were observed for the screens located downhill topographical discontinuities.

The comparative analysis between the experimental results and the predictive simulations shows a large variability of the simulations results, that illustrates the uncertainties related with these predictions, done without calibration data. Specific limitations of the block propagation models were shown as regards to the modelling of block propagation similar to rolling motion on soft soils. Finally, the simulations were shown more predictive for extreme velocities than for mean ones and for block passing probabilities.

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Analysis of Alfvénic flows with Solar Orbiter: particle and magnetic observations down to kinetic scales.
Authors: Louarn Philippe , fedorov Andrei , Rouillard alexis , Lavraud Benoit , Génot Vincent , Owen Christopher J , Bruno Roberto , Prech Lubomir , Livi Stephano , Horbury Timothy S , Maksimovic Milan ,   SWA and MAG Solar Orbiter
Published: March 2021

The magnetic and velocity fluctuations of the solar wind may be strongly correlated. This characterizes the  ‘Alfvenic’ flows. Using the observations of the Proton Alfa sensor (PAS/SWA) and the magnetometer (MAG) onboard Solar Orbiter, we analyze a period of 100 hours of such alfvenic flows, at different scales. Several parameters of the turbulence are computed (V-B correlation, various spectral indexes, cross-helicity, residual energy). We explore how these parameters may vary with time and characterize different turbulent states of the flow. More specifically, using the unprecedented time resolution of PAS during burst mode, especially its capability to measure 3D distribution functions at time scale below the proton gyroperiod, we study the connection of the turbulence to the dissipation domain and analyze the fine structure of the distribution functions and their evolutions at sub-second scales. The goal is to investigate whether some characteristics of the distributions, as their more or less pronounced temperature anisotropy, may be related to the turbulence parameters and the degree of V-B correlation.
Distributed wind measurements with multiple quadrotor UAVs in the atmospheric boundary layer
Authors: Wetz Tamino , Wildmann Norman , Beyrich Frank
Published: March 2021

A swarm of quadrotor UAVs is presented as a system to measure the spatial distribution of atmospheric boundary layer flow. The big advantage of this approach is, that multiple and flexible measurement points in space can be sampled synchronously. The algorithm to obtain horizontal wind speed and direction is designed for hovering flight phases and is based on the principle of aerodynamic drag and the related quadrotor dynamics using only on-board sensors.

During the FESST@MOL campaign at the Boundary Layer Field Site (Grenzschichtmessfeld, GM) Falkenberg of the Lindenberg Meteorological Observatory - Richard-Aßmann-Observatory (MOL-RAO), 76 calibration and validation flights were performed. The 99 m tower equipped with cup and sonic anemometers at the site is used as the reference for the calibration of the wind measurements. The validation with an independent dataset against the tower anemometers reveals that an average accuracy of σrms < 0.3 m s-1 for the wind speed and σrms,Ψ< 8° for the wind direction was achieved.

Furthermore, we compare the spatial distribution of wind measurements with the swarm to the tower vertical profiles and Doppler wind lidar scans. We show that the observed shear in the vertical profiles matches well with the tower and the fluctuations on short time scales agree between the systems. Flow structures that appear in the time series of a line-of-sight measurement and a two-dimensional vertical scan of the lidar can be observed with the swarm and are even sampled with a higher resolution than the deployed lidar can provide.

In addition to the intercomparison of the mean wind velocity measurements, turbulence data of the UAV-swarm measurements are analyzed and a comparison to sonic anemometer measurements is provided.