bluuebunny/crossref_metadata_2025 huggingface dataset:
Trajectory optimisation of satellite launch vehicles using network flow-based algorithm
Authors: Zardashti R. , Rahimi S.
Published: October 2020

A trajectory optimisation procedure is addressed to generate a reference trajectory for Satellite Launch Vehicles (SLVs). Using a grid-based discrete scheme, a Modified Minimum Cost Network Flow (MCNF)-based algorithm over a large-scale network is proposed. By using the network grid around the Earth and the discrete dynamic equations of motion, the optimum trajectory from a launch point to the desired orbit is obtained exactly by minimisation of a cost functional subject to the nonlinear dynamics and mission constraints of the SLV. Several objectives such as the flight time and terminal conditions may be assigned to each arc in the network. Simulation results demonstrate the capability of the proposed algorithm to generate an admissible trajectory in the minimum possible time compared with previous works.
Forage plant mixture type interacts with soil moisture to affect soil nutrient availability in the short term
Authors: Shepperd S. , Thomson A. , Beaumont D. , Misselbrook T. , Jones H. , Reynolds C. , Lukac M.
Published: October 2020

Agricultural intensification within forage systems has reduced grassland floral diversity by promoting ryegrass (Lolium spp.), damaging soil functionality which underpins critical ecosystem services. Diverse forage mixtures may enhance environmental benefits of pastures by decreasing nutrient leaching, increasing soil carbon storage, and with legume inclusion, reduce nitrogen fertilizer input. This UK study reports on how species-rich forage mixtures affect soil carbon, phosphorus, and nitrogen at dry, medium and wet soil moisture sites, compared to ryegrass monoculture. Increasing forage mixture diversity (from 1 to 17 species) affected soil carbon at the dry site. No effect of forage mixture on soil phosphorus was found, while forage mixture and site did interact to affect soil nitrate/nitrite availability. Results suggest that forage mixtures could be used to improve soil function, but longer-term studies are needed to conclusively demonstrate environmental and production benefits of high-diversity forages.
Reverberating theGlas: Towards a Deconstructive Account of Particularity in Hegel's Logic of the Concept
Authors: Mácha Jakub
Published: October 2020

Understanding Hegel's account of particularity has proven to be anything but straightforward. Two main accounts of particularity have been advanced: the particular as an example or instance and the particular as a subjective perspective on a universal concept. The problem with these accounts is that they reduce particularity either to singularity or to universality. As Derrida's analyses make apparent, the ‘structure of exemplarity’ in Hegel is quite intricate. Hegel uses ‘example’ in three senses: it means (1) ‘instance’, ‘illustration’, or (2) ‘model’, ‘exemplary individual’, ‘paradigm’, or (3) a by-play (a meaning derived from Hegel's neologismbeiherspielen, in whichBeispielis understood quasi-etymologically as a ‘by-play’ of accidental moments). ABeispielin the first sense can be replaced by another instance in a free play (by-play). This play of accidental moments, however, is not entirely free; it generates a series (of replacements) that ultimately leads to an example in the second sense, to an exemplary individual. I argue that particularity can be taken as exemplarity of this kind, oscillating between a singular example and a universal paradigm. Within this by-play, the universal concept, its law, is supposed to be mediated and determined. However, out of the differences between the examples the by-play induces another law, the law of non-mediation, which may, in Derrida's view, actually negate the dialectical movement towards universality. I argue, utilizing Malabou's concept of plasticity, that this disruption may be recovered. This implies that each individual example within a series is a particular determination of the universal. Hence, we can take literally Hegel's claim that the movement of the concept is play.
Catholicism Decentralized: Local Religion in the Early Modern Periphery
Authors: Kümin Beat , Tramontana Felicita
Published: October 2020

Expanding upon recent work on the heterogeneity of Catholicism and the challenges facing Tridentine reformers, this article examines local religion in two “extreme” settings: the village republic of Gersau in Central Switzerland and the missionary territory of the Custody of the Holy Land. Following conceptual remarks, the authors sketch the distinct secular contexts as well the phased evolution of localized networks for the administration of the cure of souls, the latter starting in the eleventh and sixteenth centuries, respectively. A consistently comparative approach reveals notable similarities—in terms of expanding spiritual provision and better record keeping—alongside substantial differences—especially between the clearly demarcated territorial parishes in the Alps and a more punctual system of sacrament centers in Palestine. At Gersau, where diocesan structures were weak, the church operated under the close supervision of a commune with extensive powers stretching to the rights of advowson and benefice administration. Around Jerusalem, the Franciscans—whose custos acted as the vicar apostolic—used material incentives to win over converts from other Christian denominations. Building on recent reassessments of the post-Tridentine Church, both examples thus underline the strong position of the laity in the confessional age and the need to acknowledge local sociopolitical as well as organizational factors in the formation of early modern Catholicism.
Female Monasticism in Revolutionary Times: The Nizhnii Novgorod Convent of the Exaltation of the Cross, 1917–1935
Authors: Wagner William G.
Published: October 2020

Even though after the October Revolution in 1917 the Bolsheviks enjoyed uninterrupted power and pursued radical secularist objectives, the majority of female monastic communities in Nizhnii Novgorod province were able to survive much longer than their counterparts in the French and Mexican Revolutions. Using the Convent of the Exaltation of the Cross as a case study, this article shows how—despite extremely challenging conditions and the hostility of the Soviet state—female monastic communities proved to be remarkably resilient and managed to exploit openings created by both the Bolsheviks’ strategy for subverting them and conflicts between Soviet authorities. The resiliency of the community at the Convent of the Exaltation of the Cross stemmed from the solidarity, flexibility, and leadership skills it cultivated prior to World War I through the combination of its religious character and practices and its communal organization. By the early 1920s, the community had adapted effectively to post-civil war Soviet urban conditions and was able to survive local attempts to dissolve it. But by the late 1920s, the survival of the community had become intolerable for Soviet authorities, who—like the revolutionary regimes in France and Mexico—ultimately resorted to compulsory means to “liquidate” the community between 1927 and 1935.
Acoustic shock: an update review
Authors: Parker W A E , Parker V L , Parker G , Parker A J
Published: October 2020

Background

This paper discusses the concept of acoustic shock based on a literature review and the results of our own research into cases seen in both clinical and medicolegal practice. With the demise of traditional ‘metal bashing’ and ‘smoke stack’ heavy industries, there has been a decline in the incidence of noise-induced hearing loss and tinnitus in this form of employment. However, with the increasing establishment of call centre work, the emergence of acoustic shock has been noted. Acoustic shock is recognised as a clinical entity distinct from noise-induced hearing loss and acoustic trauma.

Objective

This article discusses clinical implications, medicolegal considerations in light of a recent high-profile court case and proposed criteria for diagnosis.
Dexamethasone downregulates the expressions of MMP-9 and oxidative stress in mice with eosinophilic meningitis caused by Angiostrongylus cantonensis infection
Authors: Tsai Hung-Chin , Chen Yu-Hsin
Published: October 2020

Steroids have been shown to be beneficial in patients and mice with eosinophilic meningitis caused by Angiostrongylus cantonensis infection; however, the mechanism for this beneficial effect is unknown. We speculated that the effect of steroids in eosinophilic meningitis caused by A. cantonensis infection may be mediated by the downregulation of matrix metallopeptidase-9 (MMP-9) and oxidative stress pathways via glucocorticoid receptors (GRs). We found blood–brain barrier (BBB) dysfunction in mice with eosinophilic meningitis 2–3 weeks after infection as evidenced by increased extravasation of Evans blue and cerebrospinal fluid (CSF) albumin levels. The administration of dexamethasone significantly decreased the amount of Evans blue and CSF albumin. The effect of dexamethasone was mediated by GRs and heat shock protein 70, resulting in subsequent decreases in the expressions of nuclear factor kappa B (NF-κB), c-Jun N-terminal kinase (JNK), and extracellular signal-regulated kinase (ERK) in the CSF and brain parenchymal after 2 weeks of steroid administration. Steroid treatment also decreased CSF/brain homogenate MMP-9 concentrations, but had no effect on CSF MMP-2 levels, indicating that MMP-9 rather than MMP-2 played a major role in BBB dysfunction in mice with eosinophilic meningitis. The concentration of 8-hydroxy-2'-deoxyguanosine (8-OHdG) gradually increased after 1–3 weeks of infection, and the administration of dexamethasone significantly downregulated the concentration of oxidized derivative 8-OHdG in CSF. In conclusion, increased 8-OHdG and MMP-9 concentrations were found in mice with eosinophilic meningitis caused by A. cantonensis infection. The effect of dexamethasone was mediated by GRs and significantly decreased not only the levels of 8-OHdG and MMP-9 but also NF-κB, JNK and ERK.
Adaptive Fuzzy Finite-Time Command-Filtered Backstepping Control of Flexible-Joint Robots
Authors: Datouo Roger , Mvogo Ahanda Joseph Jean-Baptiste , Melingui Achille , Biya-Motto Frédéric , Essimbi Zobo Bernard
Published: October 2020

The problem of finite-time tracking control forn-link flexible-joint robot manipulators is addressed. An adaptive fuzzy finite-time command-filtered backstepping control scheme is presented to solve the following problems: “explosion of terms” problem, finite-time stabilization of the closed-loop system, and the reduction of computational cost. To this end, new virtual adaptive control signals and new finite-time error compensation mechanism are constructed using inherent properties of robot manipulator systems. Based on the Lyapunov theory, the finite-time stabilization of the closed-loop system is proved. Simulation studies show the effectiveness of the proposed method.
Physiology and philhellenism in the late nineteenth century: The self-fashioning of Emil du Bois-Reymond
Authors: Beiermann Lea , Wesseling Elisabeth
Published: October 2020

Argument

Nineteenth-century Prussia was deeply entrenched in philhellenism, which affected the ideological framework of its public institutions. At Berlin’s Friedrich Wilhelm University, philhellenism provided the rationale for a persistent elevation of the humanities over the burgeoning experimental life sciences. Despite this outspoken hierarchy, professor of physiology Emil du Bois-Reymond eventually managed to increase the prestige of his discipline considerably. We argue that du Bois-Reymond’s use of philhellenic repertoires in his expositions on physiology for the educated German public contributed to the rise of physiology as a renowned scientific discipline. Du Bois-Reymond’s rhetorical strategies helped to disassociate experimental physiology from clinical medicine, legitimize experimental practices, and associate the emerging discipline with the more esteemed humanities and theoretical sciences. His appropriation of philhellenic rhetoric thus spurred the late nineteenth-century change in disciplinary hierarchies and helped to pave the way for the current hegemonic position of the life sciences.
Practices of reasoning: persuasion and refutation in a seventeenth-century Chinese mathematical treatise of “linear algebra”
Authors: Chen Jiang-Ping Jeff
Published: October 2020

Argument

This article documents the reasoning in a mathematical work by Mei Wending, one of the most prolific mathematicians in seventeenth-century China. Based on an analysis of the mathematical content, we present Mei’s systematic treatment of this particular genre of problems,fangcheng, and his efforts to refute the traditional practices in works that appeared earlier. His arguments were supported by the epistemological values he utilized to establish his system and refute the flaws in the traditional approaches. Moreover, in the context of the competition between the Chinese and Western approaches to mathematics, Mei was motivated to demonstrate that the genre offangchengproblems was purely a “Chinese” achievement, not discussed by the Jesuits. Mei’s motivations were mostly expressed primarily in the prefaces to his works, in his correspondence with other scholars, in synopses of his poems, and in biographical records of some of his contemporaries.
Investigation on risk factors of haemorrhagic fever with renal syndrome (HFRS) in Xuancheng City in Anhui Province, Mainland China
Authors: Wu Guangjian , Xia Zhicai , Wang Fengtian , Wu Jiabing , Cheng Deman , Chen Xiaolong , Liu Huihui , Du Zhongjun
Published: October 2020

Haemorrhagic fever with renal syndrome (HFRS), a rodent-borne disease, is a major public health concern in both developed and developing countries. China is the most severe endemic country in the world, constituting 90% of the cases. Although the incidence of HFRS has substantively decreased in most areas of China, HFRS has rebounded remarkably in some epidemic areas. Xuancheng is one of these areas. In this study, we collected the case data reported recently in Xuancheng and designed a 1:3 case−control study. The Chi-square test, univariate and multivariate logistic regression analysis were performed. In all cases, farmers made up the highest proportion of occupations. And there were 20 variables with statistical significance including indoor hygienic conditions; the surrounding environment; whether bitten by rats at work and other criteria. In addition, exposure to rodents and rats bites is a high-risk factor for HFRS. Rodent density was calculated at 20.9% (159/760), the virus carrier rate was 9.4% (15/159) and the index of rats with a virus was about 2.0%. Exposure to rodents and insect bites is also high-risk factors for HFRS among local residents in Xuancheng. More importantly, during the flood years, the increased density of rodents led to an increased risk of human exposure to rodents. As our statistical analysis proves, targeted strategies should be developed and implemented to reduce the incidence of local diseases in the future.
A long-term look at “early starters”: Predicting adult psychosocial outcomes from childhood conduct problem trajectories
Authors: Cyr Maeve , Zheng Yao , McMahon Robert J.
Published: October 2020

Current evidence suggests that multiple pathways of “early-starting” conduct problems exist, including persisting and declining trajectories. Since relatively little is known about the early onset-declining pathway, this study examined the long-term outcomes of different childhood conduct problem trajectories in a disproportionately high-risk sample (N = 754). Parents reported on children's conduct problems at six time points (kindergarten to grade 7). At age 25, psychosocial outcomes were assessed across five domains (psychopathology, substance use, risky sexual behavior, antisocial behavior, and adaptive outcomes). Four childhood conduct problem trajectories were identified: extremely high increasing (EHI; 3.7%), high stable (HS; 22.0%), moderate decreasing (MD; 38.8%), and low decreasing (LD; 35.5%). The EHI and HS groups displayed the poorest psychosocial functioning at age 25, whereas the LD group exhibited the most positive adjustment. Although individuals in the MD group displayed relatively positive adjustment on some outcomes, they displayed more psychopathology and lower well-being in adulthood than the LD group. These findings suggest that there are diverse pathways of early-starting conduct problems, and that all early starters are at risk for later maladjustment. However, the degree and type of risk is related to the severity of conduct problems throughout childhood.
An Archaeology of the Aesthetic: Slavery and Politics at the Jesuit Vineyards of Nasca
Authors: Weaver Brendan J.M.
Published: October 2020

This article makes the case for the utility of an aesthetic approach to the archaeological record, drawing on the philosophical work of Jacques Rancière on aesthetics and politics. The case of an archaeology of African slavery on Jesuit vineyards in colonial Peru is offered to explore nuances in power and the production of enslaved subjectivities that become visible through a consideration of aesthetic fields. Of particular interest are the aesthetics of administrative policy as materialized in space and the built environment and enslaved responses through aesthetic interventions. Rather than focusing on the specific meaning or hybridity involved in the creation of the material, a Rancièrean aesthetic approach considers how materials were potentially charged with multiple, sometimes contentious meanings through activation and engagement in the aesthetic experience.
The Cost of Coronavirus Obligations: Respecting the Letter and Spirit of Lockdown Regulations
Authors: SHAW DAVID M.
Published: October 2020

We all now know that the novel coronavirus is anything but a common cold. The pandemic has created many new obligations for all of us, several of which come with serious costs to our quality of life. But in some cases, the guidance and the law are open to a degree of interpretation, leaving us to decide what is the ethical (or unethical but desired) course of action. Because of the high cost of some of the obligations, a conflict of interest can arise between what we want to do and what it is right to do. And so, some people choose to respect only the letter of the law, but not the spirit, or not to respect even the spirit of the guidelines. This paper identifies and describes the new obligations imposed on us all by the pandemic, considers their costs in terms of the good life, and provides an ethical analysis of two personal and two public cases in terms of the letter and spirit of the guidance and legislation.
Against Personal Ventilator Reallocation
Authors: REYNOLDS JOEL MICHAEL , GUIDRY-GRIMES LAURA , SAVIN KATIE
Published: October 2020

The COVID-19 (Coronavirus disease of 2019) pandemic has led to intense conversations about ventilator allocation and reallocation during a crisis standard of care. Multiple voices in the media and multiple state guidelines mention reallocation as a possibility. Drawing upon a range of neuroscientific, phenomenological, ethical, and sociopolitical considerations, the authors argue that taking away someone’s personal ventilator is a direct assault on their bodily and social integrity. They conclude that personal ventilators should not be part of reallocation pools and that triage protocols should be immediately clarified to explicitly state that personal ventilators will be protected in all cases.
EXTRAGRADIENT METHODS FOR QUASI-EQUILIBRIUM PROBLEMS IN BANACH SPACES
Authors: DJAFARI ROUHANI BEHZAD , MOHEBBI VAHID
Published: October 2020

We study the extragradient method for solving quasi-equilibrium problems in Banach spaces, which generalizes the extragradient method for equilibrium problems and quasi-variational inequalities. We propose a regularization procedure which ensures strong convergence of the generated sequence to a solution of the quasi-equilibrium problem, under standard assumptions on the problem assuming neither any monotonicity assumption on the bifunction nor any weak continuity assumption of f in its arguments that in the many well-known methods have been used. Also, we give a necessary and sufficient condition for the solution set of the quasi-equilibrium problem to be nonempty and we show that, in this case, this iterative sequence converges strongly to a solution of the quasi-equilibrium problem. In other words, we prove strong convergence of the generated sequence to a solution of the quasi-equilibrium problem without assuming existence of a solution of the problem. Finally, we give an application of our main result to a generalized Nash equilibrium problem.
Health care practitioners’ views of the support women, partners, and the couple relationship require for birth trauma: current practice and potential improvements
Authors: Delicate Amy , Ayers Susan , McMullen Sarah
Published: October 2020

Aim:

To examine health care practitioners’ views of the support women, partners, and the couple relationship require when affected by birth trauma, barriers to gaining such support, and potential improvements.

Background:

Ongoing distress following psychologically traumatic childbirth, also known as birth trauma, can affect women, partners, and the couple relationship. Birth trauma can lead to post traumatic stress symptoms (PTSS) or disorder (PTSD). Whilst there is a clear system of care for a PTSD diagnosis, support for the more prevalent experience of birth trauma is not well-defined.

Method:

An online survey of health care practitioners’ views of the support parents require for birth trauma, barriers to accessing support, and potential improvements. Practitioners were recruited in 2018 and the sample for the results presented in the article ranged from 95 to 110.

Results:

Practitioners reported differing needs of support for women, partners, and the couple as a unit. There was correlation between practitioners reporting having the skills and knowledge to support couples and feeling confident in giving support. The support most commonly offered by practitioners to reduce the impact on the couple relationship was listening to the couple. However practitioners perceived the most effective support was referral to a debriefing service. Practitioners observed several barriers to both providing support and parents accessing support, and improvements to birth trauma support were suggested.

Conclusions:

Practitioners indicate that some women, partners, and the couple as a unit require support with birth trauma and that barriers exist to accessing effective support. The support that is currently provided often conflicts with practitioners’ perception of what is most effective. Practitioners indicate a need to improve the identification of parents who need support with birth trauma, and more suitable services to support them.
Towards a Holistic Environmental Flow Regime in Chile: Providing for Ecosystem Health and Indigenous Rights
Authors: Macpherson Elizabeth J. , Weber Salazar Pia
Published: October 2020

A widespread response to the pressures placed on the ecological condition of rivers is the design and implementation of environmental flow regimes in domestic regulatory frameworks for water. Environmental interests in water are not confined to hydrological functioning but include relationships between water resources and human cultural and economic livelihoods, including those of Indigenous communities. Since the mid-1980s there has been some provision for environmental flows in Chilean law. However, the legal and policy requirements are limited in scope and have been poorly implemented by regulatory institutions. In this article we critically examine the treatment of environmental flows in Chilean legal and policy frameworks. We argue that there is an urgent need for a comprehensive minimum flow regime in Chile to protect the environmental qualities of rivers, which must also reflect and provide for Indigenous water rights and interests. The developing constitutional crisis in Chile, the most significant political crisis since the end of the Pinochet dictatorship (1973–90), highlights the need to revisit the sensitive and unresolved issues of water governance and equity.
Metabolic changes, agronomic performance, and quality of seeds in soybean with the pat gene after application of glufosinate
Authors: Albrecht Alfredo Junior P. , Brito Ivana Paula F. S. de , Albrecht Leandro P. , Silva André Felipe M. , Matos Ana Karollyna A. de , Carbonari Caio Antonio , Velini Edivaldo D.
Published: October 2020

The transgenic Liberty Link® (LL) soybean is tolerant to glufosinate, conferred by the enzyme phosphinothricin acetyltransferase (PAT), which is encoded by the pat gene from Streptomyces viridochromogenes. Because symptoms of injury can be observed in soybean [Glycine max (L.) Merr.] plants in some situations, this study evaluated the effects of rates of glufosinate on agronomic performance; quality of LL soybean seeds; and the ammonia, glufosinate, and N-acetyl-l-glufosinate concentration (NAG) in soybeans with and without the pat gene after application of increasing glufosinate rates. Field and greenhouse experiments were conducted; the first evaluated the selectivity of glufosinate in LL soybeans, and the second evaluated the metabolic changes in soybeans with (LL) and without (RR2) the pat gene, after application of glufosinate. For fieldwork, application of glufosinate at rates up to four times the maximum recommended caused initial injury symptoms (up to 38.5%) in LL soybean plants. However, no negative effect was found on seed quality and agronomic performance of LL plants, including yield. This shows the selectivity of glufosinate promoted by pat gene insertion for application in POST (V4), in LL soybean. For the greenhouse experiment, it was concluded that the LL soybean plants presented high glufosinate metabolism, lower ammonia concentration, and no reduction in dry matter, in comparison with RR2 soybean, after application of high rates of glufosinate.
Under pressure: maternal effects promote drought tolerance in progeny seed of Palmer amaranth (Amaranthus palmeri)
Authors: Matzrafi Maor , Osipitan O. Adewale , Ohadi Sara , Mesgaran Mohsen B.
Published: October 2020

The environmental conditions under which parental plants are reared can affect the seed characteristics of the progeny. The variation originating from such maternal effects has rarely been incorporated into models of seed germination. Here, using Palmer amaranth (Amaranthus palmeriS. Watson), we examined the effects of water stress during the growth of parental plants on the progeny seed characteristics, including weight, size, final germination, and parameters of a hydrotime germination model. We grew two populations (from California and Kansas) under continuous water-deficit or well-watered conditions. In bothA. palmeripopulations, progeny seeds originating from water-stressed plants were heavier and larger than those from well-watered plants. Plants exposed to water stress also produced seeds that were ~30% less dormant than seeds from control plants. To test whether the maternal environment affects the parameters of a hydrotime model, progeny seeds were subject to five water potentials (0, −0.2, −0.4, −0.6, and −0.8 MPa) and incubated at 20 and 30 C; germination was monitored daily. The estimated median base water potential (Ψb(50)), that is, the water potential at which 50% of seeds cannot germinate, was consistently lower for seeds from water-stressed plants than for seeds from well-watered plants. Our results showed thatA. palmeriplants experiencing drought during their growth produce seeds that are less dormant and can germinate from drier conditions—a maternal response that seems to be adaptive. These findings also call for development of germination models that incorporate the environmental conditions of both the current and past seasons to better describe the variability in germination of weed seeds.
Lerntherapie in Schule
Authors: Hilkenmeier Johanna , Ricken Gabi , Nolte Marianne , Ehlers Angela
Published: October 2020

Zusammenfassung. Einleitung: Vielzählige Bestrebungen, möglichst allen Schüler_innen ein gemeinsames und gleichzeitig individualisiertes Lernen zu ermöglichen, führen zu einer passenden Förderung für einen großen Teil der Schülerschaft. Einzelne Schülergruppen werden jedoch schwieriger erreicht als andere, wenn es um die Diagnostik und Förderung von Schwierigkeiten im Lesen, Schreiben und Rechnen geht. Eine direkte lerntherapeutische Anbindung vor Ort in Schule ist eine Möglichkeit, Schüler_innen schnell und niederschwellig zu erreichen, die bisher aufgrund unterschiedlicher Barrieren häufig „durchs Raster fallen“. Inwieweit und wie bundesweit Lerntherapie überhaupt in Schule verortet ist, ist bislang nicht bekannt. Methode: In diesem Beitrag wird diese Forschungslücke aufgegriffen und mittels einer Onlinebefragung von 327 Lerntherapeut_innen untersucht. Ergebnisse und Diskussion: 48 Prozent der Personen gaben an, in Schule tätig zu sein. Die konkrete organisatorische Ausgestaltung erwies sich dabei als heterogen und wurde als unterschiedlich vor- oder nachteilhaft wahrgenommen. Pfadanalysen zeigten einen positiven Zusammenhang zwischen Bedingungen für Kooperation und dem wahrgenommenen Nutzen, welcher partiell über die tatsächliche Kooperationspraxis zwischen Lerntherapeut_innen und Lehrkräften vermittelt wird.
Convection in the Magnetosphere‐Ionosphere System: A Multimission Survey of Its Response to IMF By Reversals
Authors: Case N. A. , Grocott A. , Fear R. C. , Haaland S. , Lane J. H.
Published: October 2020

Past studies have demonstrated that the interplanetary magnetic field (IMF) By component introduces asymmetries in the magnetosphere‐ionosphere (M‐I) system, though the exact timings involved are still unclear with two distinct mechanisms proposed. In this study, we statistically analyze convective flows from three regions of the M‐I system: the magnetospheric lobes, the plasma sheet, and the ionosphere. We perform superposed epoch analyses on the convective flows in response to reversals in the IMF By orientation, to determine the flow response timescales of these regions. We find that the lobes respond quickly and reconfigure to the new IMF By state within 30–40 min. The plasma sheet flows, however, do not show a clear response to the IMF By reversal, at least within 4 hr postreversal. The ionospheric data, measured by the Super Dual Auroral Radar Network (SuperDARN), match their counterpart magnetospheric flows, with clear and prompt responses at ≥75° magnetic latitude (MLAT) but a less pronounced response at 60–70 MLAT. We discuss the potential implication of these results on the mechanisms for introducing the IMF By component into the M‐I system.
“Empirical Prewhitening” Spectral Analysis Detects Periodic but Inconsistent Signals in Abyssal Hill Morphology at the Southern East Pacific Rise
Authors: Goff John A.
Published: October 2020

The existence, or not, of periodicities in abyssal hill morphology has been vigorously debated in recent publications, and some have hypothesized that such periodicities are evidence of the impact of Milankovitch cycle‐caused sea level fluctuations on the volcanic construction process at mid‐ocean ridges. Periodicities are detected by the presence of spectral peaks that rise significantly above the random variations of sample power spectra associated with an aperiodic, continuous spectrum process, typically modeled as a band‐limited fractal (von Kármán model). Here, I formulate and test a new algorithm to “empirically prewhiten” the sample power spectrum which, without needing to model the continuous spectrum, flattens it to a zero‐mean process. This greatly simplifies definition of the null hypothesis, and additional modeling approximates standard deviation levels that provide a conservative basis for detecting peaks that may be indicative of periodicity. The algorithm is applied to extensive bathymetric data flanking the southern East Pacific Rise. Significant periodicities are detected on many profiles analyzed, but the periods vary widely, and do not cluster at Milankovitch periods. The most substantial harmonic signals detected exhibit periods ∼0.082–0.216 my, with root‐mean square (RMS) heights approximately a quarter to a third of the RMS height for the aperiodic signal. It is hypothesized that the dominant aperiodic component of abyssal hills corresponds to morphology constructed by faults that follow a random distribution governed by scaling laws, whereas longer‐scale periodic signals are associated with crustal thickness variations controlled internally by variations in melt supply.
Impact of Calving Dynamics on Kangilernata Sermia, Greenland
Authors: Kane Emily , Rignot Eric , Mouginot Jeremie , Millan Romain , Li Xin , Scheuchl Bernd , Fahnestock Mark
Published: October 2020

Iceberg calving is a major component of glacier mass ablation that is not well understood due to a lack of detailed temporal and spatial observations. Here, we measure glacier speed and surface elevation at 3 min intervals using a portable radar interferometer at Kangilernata Sermia, West Greenland, for a period of 2 weeks in July 2016. We detect a 20% diurnal variation in glacier speed in phase with tidal height propagating kilometers inland. We find no speedup from ice shedding off the calving face or the detachment of floating ice blocks but a 30% speedup within a few hundred meters of the ice front that persists for days when calving removes full‐thickness grounded ice blocks. Within one ice thickness from the calving front, we detect maximum strain rates 2 to 3 times larger than observable from satellite data, which has implications for studying iceberg calving as a fracturing process.
Multiscale Coupling During Magnetopause Reconnection: Interface Between the Electron and Ion Diffusion Regions
Authors: Genestreti K. J. , Liu Y.‐H. , Phan T.‐D. , Denton R. E. , Torbert R. B. , Burch J. L. , Webster J. M. , Wang S. , Trattner K. J. , Argall M. R. , Chen L.‐J. , Fuselier S. A. , Ahmadi N. , Ergun R. E. , Giles B. L. , Russell C. T. , Strangeway R. J. , Eriksson S.
Published: October 2020

Magnetospheric multiscale (MMS) encountered the primary low‐latitude magnetopause reconnection site when the interspacecraft separation exceeded the upstream ion inertial length. Classical signatures of the ion diffusion region (IDR), including a subion‐Alfvénic demagnetized ion exhaust, a superion‐Alfvénic magnetized electron exhaust, and Hall electromagnetic fields, are identified. The opening angle between the magnetopause and magnetospheric separatrix is 30° ± 5°. The exhaust preferentially expands sunward, displacing the magnetosheath. Intense pileup of reconnected magnetic flux occurs between the magnetosheath separatrix and the magnetopause in a narrow channel intermediate between the ion and electron scales. The strength of the pileup (normalized values of 0.3 – 0.5) is consistent with the large angle at which the magnetopause is inclined relative to the overall reconnection coordinates. MMS‐4, which was two ion inertial lengths closer to the X line than the other three spacecraft, observed intense electron‐dominated currents and kinetic‐to‐electromagnetic‐field energy conversion within the pileup. MMS‐1, MMS‐2, and MMS‐3 did not observe the intense currents nor the particle‐to‐field energy conversion but did observe the pileup, indicating that the edge of the generation region was contained within the tetrahedron. Comparisons with particle‐in‐cell simulations reveal that the electron currents and large inclination angle of the magnetopause are interconnected features of the asymmetric Hall effect. Between the separatrix and the magnetopause, high‐density inflowing magnetosheath electrons brake and turn into the outflow direction, imparting energy to the normal magnetic field and generating the pileup. The findings indicate that electron dynamics are likely an important influence on the magnetic field structure within the ion diffusion region.
Precipitation Loss of Radiation Belt Electrons by Two‐Band Plasmaspheric Hiss Waves
Authors: He Zhaoguo , Yan Qi , Zhang Xiaoping , Yu Jiang , Ma Yonghui , Cao Yong , Cui Jun
Published: October 2020

A two‐band plasmaspheric hiss consisting of a low‐frequency band (normal hiss with the frequency below 2 kHz) and a high‐frequency band (locally generated hiss with the frequency up to 10 kHz) was observed on 6 January 2014 by the Van Allen Probes (He et al., 2019, https://doi.org/10.1029/2018GL081578). The electron scattering effect driven by this kind of two‐band plasmaspheric hiss is evaluated by the quasi‐linear diffusion simulation for the first time. Realistic wave characteristic parameters of the two‐band plasmaspheric hiss from statistics are adopted for driving our simulation. The pitch angle diffusion rates of the low‐frequency band hiss present a “gap” with minimum magnitude at pitch angle αe ∼ 70°, a condition not favoring the transport of large pitch angle electrons toward the loss cone. However, the diffusion rates of the high‐frequency band hiss have peak values at αe ∼ 70°, filling up for the “gap” of the low‐frequency hiss diffusion rates. The realistic wave‐driven electron PSD evolutions demonstrate that the collaborated effect of the low‐frequency band and high‐frequency band hiss can cause significant precipitation losses of energetic electrons of tens to several hundred keV within 2 days.
Statistical Characteristics of Electron Pitch Angle Distributions Inside the Magnetopasue Based on MMS Observations
Authors: Li Haimeng , Peng Qianshui , Tang Rongxin , Zhang He , Zhong Zhihong , Deng Xiaohua , Wang Dedong
Published: October 2020

Electron pitch angle distributions (PADs) are very important to understand dynamics in the Earth's magnetosphere. Using observations of the Magnetospheric Multiscale (MMS) mission, we statistically investigate the characteristics of several types of electron PADs with energies of 200 eV to 2 keV (low energy) and 2–30 keV (energetic energy) inside the dayside magnetopause (L = 8 ∼ 13). For the low (energetic) energy level, the occurrence rates of pancake, flat‐top, butterfly, isotropy, cigar, and rolling‐pin distributions are as follows: 50.34% (45.20%), 17.92% (43.41%), 3.07% (7.28%), 4.34% (1.54%), 16.20% (1.20%), and 1.80% (0.06%), respectively. The pancake PAD is mainly located at lower L‐shells with a maximum rate near the noonside, but other types of electron PADs occur at higher L‐shells. In addition, the occurrence rate of the flat‐top PAD is nearly the same for different magnetic local time. The butterfly and rolling‐pin PADs occur in the afternoon side. The cigar PAD is mostly located in both the dawnside and duskside but is very scarce in the noonside. Furthermore, the relationships between these PADs and the solar wind dynamic pressure (Pdyn) are studied. For low‐energy electrons, the occurrence rate of the pancake distribution decreases, and that of the butterfly distribution increases with the enhancement of Pdyn. However, for energetic energy level, the occurrence rate of the pancake (butterfly) PAD does not clearly decrease (increase) with the enhancement of Pdyn at L ≤ 12. The statistical results reveal the important role of Pdyn in electron dynamics inside the magnetopause.
Dominant Terms in the Freshwater and Heat Budgets of the Subpolar North Atlantic Ocean and Nordic Seas From 1992 to 2015
Authors: Tesdal Jan‐Erik , Haine Thomas W. N.
Published: October 2020

The Arctic and subarctic oceans exhibit distinct decadal variations in freshwater and heat content. We describe freshwater and heat budgets with the ECCOv4 reanalysis product and compare budget variability and mechanisms within the subpolar North Atlantic Ocean, Nordic Seas, and Labrador Sea from 1992 to 2015. For all regions, changes in freshwater content are largely anticorrelated with changes in heat content. Since 1995, the subpolar North Atlantic Ocean has undergone a decade of warming and salinification followed by ongoing cooling and freshening. The recent increase in freshwater content and the reduction in heat in the subpolar North Atlantic can largely be attributed to anomalous circulation of mean salinity and temperature, respectively. Interannual variability in heat and freshwater mostly corresponds to boundary fluxes from the subtropics. Meanwhile, the Nordic Seas have undergone an overall warming and salinification from the mid‐1990s to 2015. Salinification is primarily driven by reduced sea ice flux through Fram Strait, while warming is due to changes in both sea surface heating and advective flux. In the last 5 years, Labrador Sea freshwater convergence remained unchanged, as increased inflow via the Baffin Island Current is balanced by increased outflow via the Labrador Current. Hence, the observed freshening of the Arctic Ocean is expected to be an increasingly important source of future freshwater increases in the subpolar North Atlantic. This stands in contrast to variability in freshwater flux from the subtropical North Atlantic, which is associated with variability in the Atlantic Meridional Overturning Circulation.
Development of a Correlated Fe‐Mn Crust Stratigraphy Using Pb and Nd Isotopes and Its Application to Paleoceanographic Reconstruction in the Atlantic
Authors: Josso P. , Horstwood M. S. A. , Millar I. L. , Pashley V. , Lusty P. A. J. , Murton B.
Published: October 2020

Eight ferromanganese crust samples spanning the complete depth range of Tropic Seamount in the northeast Atlantic were analyzed for Pb and Nd isotopes to reconstruct water mass origin and mixing over the last 75 Ma. Pb isotopes were determined by laser ablation multicollector inductively coupled plasma mass spectrometer (LA‐MC‐ICP‐MS), which enables the rapid production of large, high spatial resolution data sets. This makes it possible to precisely correlate stratigraphy between different samples, compare contemporaneous layers, and create a composite record given the abundance of hiatuses in crusts. Pb and Nd isotope data show the influence of various oceanic and continental end‐members in the northeast Atlantic Ocean. This reflects its evolution from a restricted, isolated basins in the Late Cretaceous with influxes from the Tethys Ocean, to an increasingly well‐mixed, large‐scale basin, with a dominant Southern Ocean signature until the Miocene. Less radiogenic Nd isotope signatures suggest Labrador Sea Water influenced the northeast Atlantic basin as early as 17–15 Ma, flowing through a northern route such as the Charlie‐Gibbs Fracture Zone. Pb and Nd isotopes highlight the increasing influence of Saharan eolian dust input about 7 Ma, imparting a less radiogenic excursion to the binary mixing between North Atlantic water masses and riverine discharge from West and Central Africa. This highlights the influence of eolian dust input on the open ocean Pb and Nd budget and supports an early stage of North African aridification in the Late Miocene. This signature is overprinted about 3 Ma to the present by a strong North Atlantic Deep Water signature following the onset of Northern Hemisphere glaciation.
Benchmarking Forecasting Models for Space Weather Drivers
Authors: Licata Richard J. , Tobiska W. Kent , Mehta Piyush M.
Published: October 2020

Space weather indices are commonly used to drive operational forecasts of various geospace systems, including the thermosphere for mass density and satellite drag. The drivers serve as proxies for various processes that cause energy flow and deposition in the geospace system. Forecasts of neutral mass density are a major uncertainty in operational orbit prediction and collision avoidance for objects in low Earth orbit (LEO). For the strongly driven system, accuracy of space weather driver forecasts is crucial for operations. The High Accuracy Satellite Drag Model (HASDM) currently employed by the U.S. Air Force in an operational environment is driven by four solar and two geomagnetic proxies. Space Environment Technologies (SET) is contracted by the space command to provide forecasts for the drivers. This work performs a comprehensive assessment for the performance of the driver forecast models. The goal is to provide a benchmark for future improvements of the forecast models. Using an archived data set spanning 6 years and 15,000 forecasts across Solar Cycle 24, we quantify the temporal statistics of the model performance.
Wildland fire as an atmospheric source of viable microbial aerosols and biological ice nucleating particles
Authors: Moore Rachel A , Bomar Chelsey , Kobziar Leda N , Christner Brent C
Published: October 2020

The environmental sources of microbial aerosols and processes by which they are emitted into the atmosphere are not well characterized. In this study we analyzed microbial cells and biological ice nucleating particles (INPs) in smoke emitted from eight prescribed wildland fires in North Florida. When compared to air sampled prior to ignition, samples of the air–smoke mixtures contained fivefold higher concentrations of microbial cells (6.7 ± 1.3 × 104 cells m−3) and biological INPs (2.4 ± 0.91 × 103 INPs m−3 active at temperatures ≥ −15 °C), and these data significantly positively correlated with PM10. Various bacteria could be cultured from the smoke samples, and the nearest neighbors of many of the isolates are plant epi- and endophytes, suggesting vegetation was a source. Controlled laboratory combustion experiments indicated that smoke emitted from dead vegetation contained significantly higher numbers of cells, INPs, and culturable bacteria relative to the green shrubs tested. Microbial viability of smoke aerosols based on formazan production and epifluorescent microscopy revealed no significant difference in the viable fraction (~80%) when compared to samples of ambient air. From these data, we estimate each fire aerosolized an average of 7 ± 4 × 109 cells and 2 ± 1 × 108 biological INPs per m2 burned and conclude that emissions from wildland fire are sources of viable microbial aerosols to the atmosphere.
Future climate change vulnerability of endemic island mammals
Authors: Leclerc Camille , Courchamp Franck , Bellard Céline
Published: October 2020

Despite their high vulnerability, insular ecosystems have been largely ignored in climate change assessments, and when they are investigated, studies tend to focus on exposure to threats instead of vulnerability. The present study examines climate change vulnerability of islands, focusing on endemic mammals and by 2050 (RCPs 6.0 and 8.5), using trait-based and quantitative-vulnerability frameworks that take into account exposure, sensitivity, and adaptive capacity. Our results suggest that all islands and archipelagos show a certain level of vulnerability to future climate change, that is typically more important in Pacific Ocean ones. Among the drivers of vulnerability to climate change, exposure was rarely the main one and did not explain the pattern of vulnerability. In addition, endemic mammals with long generation lengths and high dietary specializations are predicted to be the most vulnerable to climate change. Our findings highlight the importance of exploring islands vulnerability to identify the highest climate change impacts and to avoid the extinction of unique biodiversity.