bluuebunny/crossref_metadata_2025_split huggingface dataset:
Heterosporangia in Isoetes Pantii (Isoetaceae, Pteridophyta): Revealing the Beginnings of Heterospory and Recalling Paleozoic Ancestors?
Authors: Bek Jiří , Goswami Hit Kishore 
Published: April 2023

Abstract
The extant plant genus Isoetes (Isoetaceae; lycophyte, quillwort) is important from an evolutionary point of view. Species of this heterosporous genus are small herbs (up to 50 centimeters) and exhibit some morphological, anatomical and embryological features of their Paleozoic arborescent lycopsid ancestors. The species Isoetes pantii produces three kinds of microspores (monolete, alete and trilete) and two types of trilete megaspores in one and the same heterosporangium. We attempt to associate these unusual functional megaspores with various Paleozoic spores described mainly from Devonian barinophytaleans such as Omniastrobus dawsonii, Barinophyton richardsonii, B. citrulliforme and Protobarinophyton pennsylvanicum. These have two kinds of spores in a sporangium and provide the first palynological evidence of heterospory at 405 Ma. The germination of microspores and megaspores and production of gametophytes within the heterosporangia of I. pantii corresponds with that of some of its Paleozoic ancestors. Retention of megaspores within heterosporangia and their germination in situ offers evidence that I. pantii exhibits the probable route of evolution of the seed habit. These observations support the hypothesis that a typical heterosporangium was the cradle for the evolution of heterospory.
Diminutive Epibionts on Crinoid Stems from the Lower/Middle Devonian Boundary in the Barrandian, Czech Republic
Authors: Mergl Michal , Šmídtová Nikola 
Published: April 2023

Abstract
Diminutive crinoid holdfasts and cemented tests of the foraminifers Psammosphaera and Tolypammina were observed on coarse bioclasts in weathered limestones of the Daleje-Třebotov Formation. Specimens were obtained in 1984 by washing so called “white beds” at a temporary locality in Praha- Barrandov. A few millimeter sized bioclasts with epibionts were freed from hard limestone beds of the Třebotov Limestone near the Lower/Middle Devonian boundary by long-term weathering. Many of the crinoid holdfasts attached to pluricolumnals provoked a stereomic response of the host crinoid. Also the growth orientation of the crinoid epibiont is not random and indicates some crinoid-epibiont to crinoidhost interaction. Reaction of host stereome and non-random stem orientation offer direct evidence of epibiont larval settlement and subsequent growth on the stem of a living crinoid host. The extensive growth of the host stereome ended by partial to total engulfing of the epibiont holdfast. This indicates advancing and finally successful defence of the host crinoid against the epibiont. The holdfast gives evidence that the small host crinoids offered a somewhat higher tier for even smaller epibiont crinoids. However, other observed holdfasts indicate fixation of larva and growth over loose bioclasts lying on a sea bed. Location of foraminifer test on bioclasts confims that foraminifers cemented and grew on loose echinodermal and brachiopod remains and preferred crevices and similar protected sites with concave profiles. This is clear evidence that diverse bioclasts (brachiopod shells, pelmatozoan ossicles) provided the hard substrate suitable for epibiont life on a sea bed.
Seminal Insights Concerning the Variety of Sidertic Structures and Variable Genesis and of Sideritic Occurrences: An Unexplored Source of Palaeontological Information (Sydney Coalfield, Middle Pennsylvanian, Canada)
Authors: Zodrow Erwin L. , Pšenička Josef 
Published: April 2023

Abstract
Reported are descriptions of twelve samples representing a variety of sideritic structures, including nodules mostly from roof shale of the Middle Pennsylvanian Sydney Coalfield, Canada. The co-occurrence of fossiliferous nodules and compression fossils in the shaley roof rocks at Point Aconi enhance greatly palaeontological information. Newly discovered in a coal seam, and part of the sample, is a 40 mm thick continuous sheet-like layer of siderite with abundant permineralized-like-compressed small to micron-sized structures in a rather evenly-sized sideritic matrix, probably indicating a genetic origin different from that of the nodules. Methods include some thin-section, and two X-Ray analysis. However, large systematic sampling is a prerequisite to explore that situation, which additionally could provide faunal information for Euromerican correlation.
The Rare Trilobites Exallaspis (Odontopleuridae) and Kosovoproetus? (Tropidocoryphidae) in the Homerian (Silurian) Of The Prague Basin, Bohemian Massif
Authors: Hartl František , Vokáč Václav , Pavlovič Miroslav , Mrázek Tomáš , Šafka Martin 
Published: April 2023

Abstract
The deep-water Aulacopleura koninckii Assemblage in the lower Homerian (T. testis Sub-Biozone) “Aulacopleura shales“ strata at the classical ‘Barrande’s pits’ locality on the Černidla hillside at Loděnice in the Prague Basin is supplemented by the addition of two new trilobite taxa, viz. Exallaspis? perunicana sp. n. and Kosovoproetus? aff. praecursor (Přibyl & Vaněk 1987). The palaeogeographic distribution of Exallapis Ramsköld & Chatterton, 1991 is extended by the occurrence of Exallaspis? perunicana sp. n. and the younger Exallaspis sp. in the upper Homerian (the P. parvus – G. nassa Biozone) of the Prague Basin, reflecting the faunal migration between the southern shelf of the Baltica palaeocontinent and the Perunica microcontinent accross the Rheic Ocean. The small dimensions of the K.? aff. praecursor exoskeletons compared to those of K.? praecursor in the bordering shallow-water Liolalax–Sphaerexochus– Cheirurus Assemblage represent another example of adaptive nanism in trilobites of the Aulacopleura-Raphiophorus Biofacies.
Construction of the Metro Line D in Praha-Pankrác: An Introductory Report About a Unique Opportunity for Study of the Upper Ordovician Fossil Assemblages and Sediments in the Prague Basin (Czech Republic)
Authors: Bruthansová Jana , Bruthans Jiří , Kraft Petr 
Published: April 2023

Abstract
The construction of the new metro line D in Praha-Pankrác provides a unique opportunity to study different aspects such as lithology, stratigraphy and fossil assemblages from the Upper Ordovician and Silurian of the Prague Basin. Results from the sections in tunnels mined so far allowed detailed information about the succession of fossil assemblages, facies variability and actual thicknesses of the upper part of the Bohdalec Formation, the Králův Dvůr and Kosov formations in this part of Prague Basin. The stratigraphic position of Michle Facies in the Bohdalec Formation was also indicated.
Internationalisation of Higher Education Curriculum as a Strategy for Preparing Future Youth Workers
Authors: Sawicki Krzysztof , Żyłkiewicz-Płońska Emilia 
Published: April 2023

Abstract
Educating future youth workers is a particular challenge for higher education. It results not only in the acquisition of basic knowledge and skills, but also in the implementation of the glocal perspective. In this aspect, the process of internationalization of higher education is a key element enabling optimal shaping of future youth workers’ vocational identity.
The article presents an international strategic partnership project enabling such activities in the area of bachelor’s studies. Its theoretical layer (Positive Youth Development) and intellectual outputs were presented. Moreover, learning, teaching and training activities, which are the result of the testing of the educational module, were introduced. The opportunity to participate in such international activities enables future social professionals to creatively approach youth problems at the local level using a broader perspective and mechanisms based not only on identifying risk and problems but also on resources and opportunities for positive development. The results worked out in the project can form the basis to develop learning, teaching and training activities for future youth workers outside partner universities.
The Result of the Meeting of Voluntary Migrants with Forced Migrants at the Volunteering Background – Research Report
Authors: Butarewicz-Głowacka Agata , Dowgiert Martyna , Suchocka Amelia 
Published: April 2023

Abstract
The aim of the paper is to present the specificity of voluntary work of Erasmus+ Spanish students (voluntary migrants) in aid of children in Polish primary schools attended by foreigners (often forced migrants). The first – theoretical part of the text presents the outline of migration issues, including forced and educational migration as well as voluntary work. The second part of the text shows methodological assumptions of qualitative research, which was conducted using the method of individual cases in June 2022 among Spanish volunteers working on behalf of the Dialog Foundation in Bialystok, Poland. Chosen research results concerning the activities undertaken by the volunteers, their motivation to act and the multilateral benefits from their work have been shown. In the light of the results of the research, Spanish volunteers contributed to the integration of pupils in the primary schools, in which they conducted workshops. The results of the research may hopefully be useful to develop further educational research concerning volunteering in aid of children in an intercultural environment.
Value Behaviour Norm Theory Approach to Predict Private Sphere Pro-Environmental Behaviour among University Students
Authors: Arya Bhavana , Kumar Harshita 
Published: April 2023

Abstract
Despite the fact that university students have significant potential to influence the future state of the environment, few academic researchers have focused on environmental behaviour among university students in less developed and developing countries. In the extant literature, there is a need to assess the significance of value behaviour norm theory in different ‘private-sphere’ or ‘daily life’ human behaviours. This paper aimed to assess a possible chain effect between individual values, environmental consciousness and personal norms to promote private sphere Pro-Environmental behaviour among university students. (N = 267). Multiple regression analysis results revealed that Altruistic Values (AV), Egoistic Values (EGV), New Ecological Paradigm (NEP), and Ascription of Responsibility (AR) significantly predicted Pro-Environmental Behaviour (PEB). However, Biospheric Values (BV), Awareness of Consequences (AC), and Personal Norm (PPN) do not significantly predict Pro-Environmental Behaviour (PEB). The Value Behaviour Norm Theory (VBN) model explained a significant amount of variance (65.6 %) in predicting Private Sphere Pro-Environmental Behaviour in University Students. Results indicate that University students may benefit from awareness programs on the VBN model which may improve their Pro-Environmental behaviour.
Blockchain for open scientific collaboration and impact (published in AESIS General Newsletter November 2022)
Authors: Sharples Michael 
Published: April 2023

<strong><span style="font-size:12.0pt"><span style="font-family:&quot;Trebuchet MS&quot;,sans-serif"><span style="color:maroon">Blockchain for open scientific collaboration and impact</span></span></span></strong><br />
<strong><span style="font-size:9.0pt"><span style="font-family:&quot;Trebuchet MS&quot;,sans-serif"><span style="color:#202020">Authors: Mike Sharples, Emeritus Professor of Educational Technology Institute of Educational Technology, The Open University, and Jason E. Barkeloo, Founder/Chair, Open Therapeutics, United Kingdom.</span></span></span></strong><br />
<br />
<span style="font-size:9.0pt"><span style="font-family:&quot;Trebuchet MS&quot;,sans-serif"><span style="color:#202020">How do you set up an incentive system that rewards scientists for open collaboration? That was the issue tackled in “<a href="https://aesisnet.us7.list-manage.com/track/click?u=7807491176d53828422c909a9&amp;id=9a14c1d7ec&amp;e=2a8df0b947" style="color:blue; text-decoration:underline" target="_blank"><span style="color:#222222">The Blockchain and Kudos: A Distributed System for Educational Record, Reputation and Reward</span></a>”. That approach uses a blockchain, best known for recording cryptocurrency transactions, at the heart of a new scientific record and reward system. Organizations and intellectual workers are given an initial award of “educational reputation currency” (“Kudos”) stored on a blockchain. Then any person or institution can make a reputational transaction. An institution might announce a breakthrough by posting the findings on the blockchain and transferring some of its Kudos to the team that did the work. An individual could publish a paper on the blockchain which is timestamped and archived. Other people then transfer some of their Kudos to the author, to boost the reputation of that person’s work. The basic idea – combining blockchain, open collaboration, and reputation currency – is the core of the open science platform <a href="https://aesisnet.us7.list-manage.com/track/click?u=7807491176d53828422c909a9&amp;id=0c27267373&amp;e=2a8df0b947" style="color:blue; text-decoration:underline" target="_blank"><span style="color:#222222">Therapoid</span></a>. It provides researchers with <a href="https://aesisnet.us7.list-manage.com/track/click?u=7807491176d53828422c909a9&amp;id=5c74c01fac&amp;e=2a8df0b947" style="color:blue; text-decoration:underline" target="_blank"><span style="color:#222222">ScienceCoins</span></a> cryptocurrency when they collaborate. Researchers and students in economically challenged areas could particularly benefit from the monetary awards. This award model can be extended to non-fungible tokens (NFTs), which can also be monetized.</span></span></span>
Envelope-Based Grid-Point Approach: Efficient Runtime Complexity for Remote Sensing Coverage Analysis
Authors: Sipps Jonathan , Magruder Lori 
Published: April 2023

Modern remote sensing science objectives call for multi-instrument measurement collection under ever-stringent mission requirements. Distributed spacecraft missions (DSMs) answer the demand, with multisatellite mission architectures, capable of short revisit intervals and expansive coverage capacity. Variations in instrument, orbit, and the number of satellites expand the trade space combinatorically, leading to a computationally demanding mission design problem. Evaluating trade space intelligently is prevalent in literature, but the fundamental computational burden rests on figure of merit (FOM) calculation, quantifying architecture performance. The grid-point approach (GPA) and quick search and correction (QSC) methods are used to develop FOMs, but poor efficiency leads to slow evaluation of prospective DSM candidates. In this paper, a novel method is introduced, envelope grid-point approach (EGPA), fulfilling the need for faster DSM FOM calculation. The EGPA runtime is nearly invariant to temporal accuracy and varies by the inverse of grid cell size (GCS) for constant GCS-to-swath ratio, thereby scaling to high temporal and spatial resolution. The new method EGPA is validated with GPA for conical and rectangular fields of view, and then the performance of EGPA is compared against QSC, a modern improvement of GPA. Both are compared for a computationally demanding Walker Delta constellation (80°:6/3/1) over 1 day propagation, demonstrating EGPA utility in quickly determining FOMs for DSM design.
Scramjet Engine Flowpath That Improves Specific Impulse Using JP-7 Fuel
Authors: Choi Yunseok , Driscoll James F. 
Published: April 2023

A flowpath geometry was computed that improves the specific impulse of a dual-mode scramjet engine in a generic X-51 hypersonic vehicle. Six parameters were varied: inlet contraction ratio, the diameters and numbers of fuel injectors, divergence angle of the combustor wall, nozzle flap deflection angle, and flight Mach number. The maximum specific impulse [Formula: see text] was 2296 s in the ram mode and 832 s in the scram mode. A reduced-order model simulates the finite-rate chemistry of JP-7 fuel and the unstart limits. Results show that both combustion efficiency and [Formula: see text] drop to unacceptably low levels when the finite-rate chemical reaction rates are weakened by flame strain-out due to the large air velocities, or when the flame becomes longer than the combustor. Small [Formula: see text] occurs when the following are too small: the inlet contraction ratio, the inlet compression ratio, the number of fuel injectors, and the diameter of fuel injectors. When these parameters are too large, excessive heat release causes unstart. The operating range was identified between these limits. For JP-7 fuel, it was found that the inlet should raise the pressure to above 5 atm. Results are explained by the interactions between reactions, mixing, and flame strain-out.
Decentralized Observation Allocation for a Large-Scale Constellation
Authors: Parjan Shreya , Chien Steve A. 
Published: April 2023

Increased space sensing enables new measurements of a wide range of Earth science phenomena including volcanism, flooding, wildfires, and weather. Large-scale observation constellations of hundreds of assets have already been deployed (for example, Planet Labs’s Dove satellites), and several constellations of tens of thousands of assets are planned. New challenges exist to rapidly assimilate available data and to optimize measurements by directing spacecraft assets to best observe complex Earth science phenomena. Centralized approaches to managing request allocation in these large constellations are constrained by 1) the need to assign/elect a central node to assign requests to spacecraft and 2) reliance on a single agent communicating with potentially thousands of dependent agents. On the other hand, entirely decentralized approaches to request allocation and observation are prone to oversatisfaction of some requests and undersatisfaction of others due to a lack of communication among agents. In large constellations, an intermediary method is necessary to solve the request allocation problem in a distributed manner. We present distributed artificial intelligence/multiagent methods that leverage existing work on distributed constraint optimization to allocate observations in a satellite constellation. We compare their performance to centralized and highly decentralized approaches using realistic orbits and observation request distributions. Our distributed algorithms can find approximate solutions to the large-scale constellation request allocation problem with low data volume for agent coordination and extend to continuous planning problems with varying request sets and availability of spacecraft agents.
Measurement and Identification of Supersonic Stationary Crossflow Waves Based on Sublimation Method
Authors: Yuan Jisen , Yu Shenghao , Gao Liangjie , Qian Zhansen 
Published: April 2023

Aiming at the crossflow transition problem of supersonic swept wings, an experimental study on the measurement and identification of boundary-layer stationary crossflow waves was carried out at Mach number 2.0. A 65 deg straight-swept-wing model with simple airfoil geometry was designed to capture the crossflow transition phenomenon. The sublimation method for a large-scale cold supersonic wind tunnel was developed to acquire a transition pattern. The stationary crossflow wave identification technology is based on image processing, a vertical and horizontal decomposition method is established, and the quantitative characteristic information (such as the vortex axis spacing and direction) can be identified from high-resolution sublimation images. The experimental results show that the transition position caused by crossflow instability is closed to the leading edge for supersonic wings with large sweep angles at high Reynolds numbers, and the transition position moves upstream with the increase of the unit Reynolds number. The identified vortex axis spacing and direction are basically consistent with the linear stability theory. The stationary disturbance wave information at different Reynolds numbers is compared and analyzed. It is found that the unit Reynolds number plays an important role in the selection and amplification of the unstable stationary modes with different wavelengths in the transition process.
Flows Generated by Electrohydrodynamic Gas Pumps with Different Electrode Orientations
Authors: Mazumder A. K. M. Monayem H. , Lai Feng C. 
Published: April 2023

Numerical simulations have been performed to examine the flows inside a square channel produced by a two-stage electrohydrodynamic (EHD) gas pump with two electrode arrangements. The EHD pump has a pair of seven emitting electrodes flush mounted on two parallel walls at each stage. The flush-mounted electrodes produce corona wind similar to a wall jet that is mainly responsible for flow delivery. The pump is operated by a combination of three different voltages (24, 26, and 28 kV) for performance improvement. Because flow visualization is very challenging to implement in experimental study of EHD flows, very few results are available in the literature. As such, this study is specifically aimed at providing additional insight to the flowfield inside the channel through visualization of the numerical results obtained. Also, the overall effectiveness of the EHD gas pump is evaluated by the volume flow rate delivered as well as its power efficiency. It has been found that the power efficiency for the EHD pumps considered is higher than the conventional fans/pumps. Thus, they have a great potential for applications in thermal management. Particularly, they can be more energy efficient when they are operated by uneven applied voltages.
Explicit-implicit scheme CABARETI–NH for the equations of a weakly compressible fluid dynamics
Authors: Головизнин В.М. , Майоров П.А. , Афанасьев Н.А. , Майоров П.А. , Соловьев А.В. 
Published: April 2023

В статье рассматривается явно-неявная балансно-характеристическая схема CABARETI–NH (CABARET Implicit Non-Hydrostatic), основанная на схеме КАБАРЕ, для решения гиперболизированной системы уравнений Навье–Стокса. Неявность вдоль одного пространственного направления позволяет значительно увеличить шаг по времени на вычислительных сетках с большим аспектным отношением ячеек. Для разрешения введенной неявности используется метод гиперболической прогонки. Это позволяет сохранить вычислительную эффективность алгоритма на уровне явных схем. Приводятся результаты валидации модели на лабораторном эксперименте трехмерного гравитационного течения стратифицированной жидкости.
In this paper, an explicit-implicit conservative-characteristic scheme CABARETI–NH (CABARET Implicit Non-Hydrostatic), based on the CABARET scheme, for a hyperbolised system of Navier–Stokes equations is considered. Implicitness along one spatial direction allows the time step on computational grids with a large aspect ratio of cells to be significantly increased. A hyperbolic sweep method is used to resolve the introduced implicit part of the scheme. This keeps the same level of computational efficiency as explicit schemes. The results of model validation on the laboratory experiment of three-dimensional gravitational flow of a stratified fluid are presented.