bluuebunny/crossref_metadata_2025 huggingface dataset:
Large-scale circulation reversals explained by pendulum correspondence
Authors: Moore Nicholas J. , Huang Jinzi Mac
Published: September 2024

We introduce a low-order dynamical system to describe thermal convection in an annular domain. The model derives systematically from a Fourier–Laurent truncation of the governing Navier–Stokes Boussinesq equations and accounts for spatial dependence of the flow and temperature fields. Comparison with fully resolved direct numerical simulations (DNS) shows that the model captures parameter bifurcations and reversals of the large-scale circulation (LSC), including states of (i) steady circulating flow, (ii) chaotic LSC reversals and (iii) periodic LSC reversals. Casting the system in terms of the fluid's angular momentum and centre of mass (CoM) reveals equivalence to a damped pendulum with forcing that raises the CoM above the fulcrum. This formulation offers a transparent mechanism for LSC reversals, namely the inertial overshoot of a forced pendulum, and it yields an explicit formula for the frequency

$f^*$

of regular LSC reversals in the high-Rayleigh-number (Ra) limit. This formula is shown to be in excellent agreement with DNS and produces the scaling law

$f^* \sim {Ra}^{0.5}$

.
Swimming efficiently by wrapping
Authors: Gidituri H. , Ellero M. , Balboa Usabiaga F.
Published: September 2024

Single-flagellated bacteria are ubiquitous in nature. They exhibit various swimming modes using their flagella to explore complex surroundings such as soil and porous polymer networks. Some single-flagellated bacteria swim with two distinct modes, one with the flagellum extended away from its body and another with the flagellum wrapped around it. The wrapped mode has been observed when bacteria swim under tight confinements or in highly viscous polymeric melts. In this study we investigate the hydrodynamics of these two modes inside a circular pipe. We find that the wrapped mode is slower than the extended mode in bulk but more efficient under strong confinement due to a hydrodynamic increase of its flagellum translation–rotation coupling and an Archimedes’ screw-like configuration that helps to move the fluid along the pipe.
Undulatory swimming in suspensions and networks of flexible filaments
Authors: Townsend Adam K. , Keaveny Eric E.
Published: September 2024

Many biological fluids are composed of suspended polymers immersed in a viscous fluid. A prime example is mucus, where the polymers are also known to form a network. While the presence of this microstructure is linked with an overall non-Newtonian response of the fluid, swimming cells and microorganisms similar in size to the network pores and polymer filaments instead experience the heterogeneous nature of the environment, interacting directly with the polymers as obstacles as they swim. To characterise and understand locomotion in these heterogeneous environments, we simulate the motion of an undulatory swimmer through three-dimensional suspensions and networks of elastic filaments, exploring the effects of filament and link compliance and filament concentration up to 20 % volume fraction. For compliant environments, the swimming speed increases with filament concentration to values approximately 10 % higher than in a viscous fluid. In stiffer environments, a non-monotonic dependence is observed, with an initial increase in speed to values 5 % greater than in a viscous fluid, followed by a dramatic reduction to speeds just a fraction of its value in a viscous fluid. Velocity fluctuations are also more pronounced in stiffer environments. We demonstrate that speed enhancements are linked to hydrodynamic interactions with the microstructure, while reductions are due to the filaments restricting the amplitude of the swimmer's propulsive wave. Unlike previous studies where interactions with obstacles allowed for significant enhancements in swimming speeds, the modest enhancements seen here are more comparable to those given by models where the environment is treated as a continuous viscoelastic fluid.
Magnetohydrodynamic flow control in Hele-Shaw cells
Authors: McKee Kyle I.
Published: September 2024

Consider the motion of a thin layer of electrically conducting fluid, between two closely spaced parallel plates, in a classical Hele-Shaw geometry. Furthermore, let the system be immersed in a uniform external magnetic field (normal to the plates) and let electrical current be driven between conducting probes immersed in the fluid layer. In the present paper, we analyse the ensuing fluid flow at low Hartmann numbers. Physically, the system is particularly interesting because it allows for circulation in the flow, which is not possible in the standard pressure-driven Hele-Shaw cell. We first elucidate the mechanism of flow generation both physically and mathematically. After formulating the problem using complex variables, we present mathematical solutions for a class of canonical multiply connected geometries in terms of the prime function framework developed by Crowdy (Solving Problems in Multiply Connected Domains, SIAM, 2020). We then demonstrate how recently developed fast numerical methods may be applied to accurately determine the flow field in arbitrary geometries.
The instability of non-monotonic drag laws
Authors: Radko Timour
Published: September 2024

A series of recent studies has indicated that the component of the bottom drag caused by irregular small-scale topography in the ocean varies non-monotonically with the flow speed. The roughness-induced forcing increases with the speed of relatively slow abyssal currents but, somewhat counterintuitively, starts to decrease when flows are sufficiently swift. This reduction in drag at high speeds leads to the instability of laterally uniform currents, and the resulting evolutionary patterns are explored using numerical and analytical methods. The drag-law instability manifests in the spontaneous emergence of parallel jets, aligned in the direction of the basic flow and separated by relatively quiescent regions. We hypothesize that the mechanisms identified in this investigation could play a role in the dynamics of zonal striations commonly observed in the ocean.
Relative dispersion in free-surface turbulence
Authors: Li Yaxing , Wang Yifan , Qi Yinghe , Coletti Filippo
Published: September 2024

We report on an experimental study in which Lagrangian tracking is applied to millions of microscopic particles floating on the free surface of turbulent water. We leverage a large jet-stirred zero-mean-flow apparatus, where the Reynolds number is sufficiently high for an inertial range to emerge while the surface deformation remains minimal. Two-point statistics reveal specific features of the flow, deviating from the classic description derived for incompressible turbulence. The magnitude of the relative velocity is strongly intermittent, especially at small separations, leading to anomalous scaling of the second-order structure functions in the dissipative range. This is driven by the divergent component of the flow, leading to fast approaching/separation rates of nearby particles. The Lagrangian relative velocity shows strong persistence of the initial state, such that the ballistic pair separation extends to the inertial range of time delays. Based on these observations, we propose a classification of particle pairs based on their initial separation rate. When this is much smaller than the relative velocity prescribed by inertial scaling (which is the case for the majority of the observed particle pairs), the relative velocity transitions to a diffusive growth and the Richardson–Obukhov super-diffusive dispersion is recovered.
Double diffusive convection in the diffusive regime with a uniform background shear
Authors: Li Junyi , Yang Yantao
Published: September 2024

This study proposes a new mechanism that can lead to layering or convection from the finite amplitude perturbation acting on the double diffusive convection with uniform background shear. We focus on the double diffusive convection in the diffusive regime with the cold fresh water laying above the warm salty water. We demonstrate that, although the unperturbed system is linearly stable, the finite amplitude perturbation can trigger the initial flow motions which subsequently obtain energy from the gravitational potential energy and from the uniform background shear, and evolve to layering or convection. By using the linear stability analysis for the initial growth stage and the energy analysis for the following transitional stage, the critical Richardson number can be predicted theoretically. Here the Richardson number measures the relative strength of stratification to the background shear. The dominant wavenumbers and the growth rates of the corresponding modes given by linear theory agree well with the two-dimensional direct numerical simulations, and so does the critical Richardson number predicted by the theoretical model. The layering state is dominated by the double diffusion process, while the convection state at smaller Richardson number exhibits stronger influences from shear and generates smaller heat and salinity fluxes. The theoretical model is further applied to the parameter range which is relevant to the real oceanic environments and reveals that for the typical density ratio observed in the staircase regions in the Arctic Ocean, the current mechanism can lead to layering for relatively weak shear.
Culpeper’s herbal The English Physitian and its debt to apothecary John Parkinson
Authors: Tobyn Graeme
Published: September 2024

In this textual comparison of seventeenth-century herbals, I show in detail that most of the descriptions and medicinal uses of English herbs included in Culpeper’s small folio The English Physitian (1652) and its enlargement of the following year were lifted straight out of the works of John Parkinson, apothecary. This was a deliberate act by Culpeper, to make available to the people of England the best information on native plant medicines for use in treating their illnesses. He attacked the College of Physicians of London, whom the great majority of the population could not afford to engage, for trying to keep this knowledge secret. Among later historians of the herbal tradition, Culpeper’s work was not accorded the same status as the great English herbals of William Turner, John Gerard, and John Parkinson, not because this borrowing was recognised but because its astrological content worked to divert attention from the quality and source of much of its guidance on treatment. Even contemporaries of Culpeper did not recognise the extent of the borrowing. Comparisons also reveal the limitations of Culpeper’s powers of plant description and his lack of interest in the developing science of botany. The editorial decisions Culpeper made to reduce a great folio herbal to a much smaller book to be sold for 3d touch on domestic and other non-medical uses, while points of discussion common to both authors such as the doctrine of signatures and superstitious beliefs about plants are explored.
MONOGENIC EVEN QUARTIC TRINOMIALS
Authors: JONES LENNY
Published: September 2024

A monic polynomial$f(x)\in {\mathbb Z}[x]$of degreeNis calledmonogenicif$f(x)$is irreducible over${\mathbb Q}$and$\{1,\theta ,\theta ^2,\ldots ,\theta ^{N-1}\}$is a basis for the ring of integers of${\mathbb Q}(\theta )$, where$f(\theta )=0$. We prove that there exist exactly three distinct monogenic trinomials of the form$x^4+bx^2+d$whose Galois group is the cyclic group of order 4. We also show that the situation is quite different when the Galois group is not cyclic.
The Long Shadow of the Working Class Movement
Authors: Wickham James
Published: September 2024

This paper explores how the years after World War II in Western Europe were an extreme case of working-class power. An initial theoretical discussion claims that while class can best be understood as a social category, at the same time politics in the broadest sense—and hence class-based movements—can shape social structure. This was the case in the in the post-World War II period when the working class dominated West European societies: especially perhaps in Britain, the “weight” of the working class shaped the nation. Trade union organization and state power ensured collective rights and were the basis for autonomous consumption; class identity was a source of pride. The end of this period saw trade union density continuing to increase. In the USA as well as in Western Europe, the power of management in the workplace was challenged. Especially in Western Europe, there was widespread radicalization of working-class youth. This was the last offensive of the working-class movement. However, power in the workplace remained essentially a veto-power. In the USA, oppositional politics became ethnic politics and even before de-industrialisation the white working class began to abandon its traditional politics. Nonetheless, in Western Europe the long shadow of the working-class movement ensured the partial survival of social rights long after the traditional social basis of the movement had withered away.
The Gospel Of Peace
Authors: Editor The
Published: September 2024

We have learnt to expect Christmas words that echo the song of the angels of Bethlehem from the peaceful Pope, Pacelli. This year Pius XII may feel that his words have had some effect at least in the cessation of hostilities in Korea, but he will still be faced with deep-seated and incessant conflicts the world over; of there remains as urgently as ever the need for the Vicar of Christ to preach Christ's gospel of peace. We shall still look to him for leadership in this work, begun at the birth of our Lord, to knock down the walls of partition and to effect the killing of enmities in the flesh of Christ. ‘And coming he preached peace to you that were afar off, and peace to them that were nigh’ (cf. Ephesians 2).
The Daughters Of St Catherine Of Siena: A Dominican Initiative
Authors: Pond K.
Published: September 2024

When the Holy Father gave to the Christian world both the Apostolic Constitution Provida Mater Ecclesia and the Motu Proprio Primo Feliciter, it was not to present the Church with something novel in the search for Christian perfection but rather to set the seal of his approval on a form of life, wholly given to God, already being lived by many who, for various reasons, were unable to enter a religious Order or who perhaps felt that a consecrated life in the world gave them greater scope for the exercise of their apostolate. It was natural—and indeed eminently desirable—that some of the attempts at the dedicated life in the world should be grouped around the contemplative Orders—Benedictines, Carmelites, Dominicans— for the fact that such a life is lived in the world makes whatever contact with a centre of contemplative life is possible all the more valuable and indeed essential.
Fruits Of Captivity
Authors: A.M.
Published: September 2024

Both under the Old Dispensation and under the New, God has often used the scourge of war, exile and captivity to summon his people to a renewal of faith, to call them to repentance and conversion. Christians have had to undergo this experience in our own times in Europe and Asia, and accounts of their witness to their faith are reaching us from many quarters. What grace and profit may accrue to the Church from their fidelity and their sufferings we cannot tell: that is in God's hands. But might it not be, also, that in his providential plan for us there is a place for the published records of such experiences, many of them by our separated brethren, which we have not yet learnt to appreciate sufficiently? Perhaps, in one sense, it is too easy to be impressed by the courageous stand of a Faulhaber or a Niemöller; perhaps we are too readily moved by the joy and serenity in the letters of a von Moltke, written from prison, awaiting execution, condemned for the sole reason that he had confessed to placing loyalty to God above that to his Führer.
Meditation
Authors: Valentine Ferdinand
Published: September 2024

In addition to the kind of mental prayer we have already considered,
there is another which usually goes by the name of Meditation. We have
already spoken of vocal prayers in which set words precede and circumscribe
the thought. In the mental prayer called Meditation on the other hand it is
the thought which precedes and elicits the words or spontaneous acts. There
is sufficient truth in the aphorism ‘Vocal prayer is meaning what we say,
but meditation is saying what we mean’ to distinguish between these
approaches.

In general, we may say of meditation that the closer the soul draws to
God through habitual collaboration with his Will, the more ardently will it
desire God in time of prayer and the less will it rely on preliminary
meditation. This need for meditation varies also with disposition,
Penpenient and many other factors. St Teresa of Avila, for instance, found
great difficulty in collecting her thoughts and for many years used a book
to start her prayer. ‘I could not meditate without a book’, she says. This
does not mean she made formal meditation.
The Beginning of the Way
Authors: Pepler Conrad
Published: September 2024

Is there be any need to defend the introduction of William Langland into
a treatise on English mysticism and the spiritual life we may refer the
reader to Christopher Dawson’s brilliant essay in The English
Way. “This popular tradition of English religion’, he
writes of Fox, Bunyan and Blake, ‘which was divorced from Catholic unity and
even from the national unity after the 17th century already exists in its
purest and most unadulterated form in the work of Langland. He shows us what
English religion might have been if it had not been broken by schism and
narrowed by sectarianism and heresy’. And again: ‘Langland embodies the
spiritual unity of the English people at the very moment when religion in
England stood at the parting of the ways’. Piers
Plowman, the virile and powerful poem of the English
people, provides a solid basis for a truly English type of
spirituality.
A Disciple of St John of the Cross
Authors: Murray Rosalind
Published: September 2024

There can be few saints more unlike at first sight than St Teresa of the Child Jesus and St John of the Cross. Their personalities, their ‘ways’ of perfection, their appeal, are outwardly at the poles of recognised Christian spirituality. And this first impression seems confirmed by a glance at their respective cults, the extreme difference of their ‘clientèle'. How few, how very few, of the real devotees of either saint extend at all the same devotion to the other!

Yet both were contemplatives, both Carmelites and, more than that, the teaching of St John of the Cross was formative in a special degree, explicitly, in the spiritual life of the ‘little’ St Teresa.
Meditation
Authors: Jarrett Bede
Published: September 2024

I suppose one of the things the importance of which seems to be everywhere recognised is the extraordinary way in which human beings are subject to their environments, are influenced and affected by them. Some sort of subconscious power registers all sorts of details which we didn't know we had even noticed and years after some insignificant act or word comes to life. A name in a newspaper brings back an old world, just the chance hearing of a name and back out of the past springs vividly to our imagination just a scene, and we realise from that how very much we are under the spell of circumstances. At times it would seem that we owe to heredity all that we are, not necessarily to our immediate parents but to our ancestors in the past, a throw back, and now all that idea is given up and what people do think a great deal of is surroundings, the lines in which our lives are cast.
David (II)
Authors: Humphries Silvester
Published: September 2024

David fulfils the long-hoped-for ambition of all Israel in taking Jerusalem, and establishes himself there with the ark of God, the central, sacramental thing in the religion of the chosen people. He is unaware that his own kingly office is to become a no less venerated centre in the dynasty he founds. for to be king of Jerusalem entailed far-reaching consequences. To be the anointed of Israel gave him an office that could be set in rivalry beside the priesthood of the house of Aaron; and to the general populace of Israel (especially the tribes that had no love for Levi and what they deemed its pretensions) he, not the successor of Aaron, was the spiritual head of the nation.
Myocardial infarction and narrowed peripheral arterial vessels secondary to generalised arterial calcification syndrome in a two-month-old girl
Authors: Toprak Muhammet Hamza Halil , Ozturk Erkut , Hatemi Ali Can , Gezdirici Alper , Tanidir İbrahim Cansaran
Published: September 2024

Generalised arterial calcification of infancy, an autosomal recessive disorder characterised by abnormal calcification of medium and large-sized arteries, represents a rare cause of dilated cardiomyopathy. We present the case of a two-month-old girl diagnosed posthumously with dilated cardiomyopathy. Studies suggest that early initiation of treatment can improve prognosis in generalised arterial calcification of infancy, so clinicians should be alert to the condition, especially in patients displaying generalised narrowing of medium and large-sized arteries.
Surgical management of congenital mitral stenosis in a patient with Kabuki syndrome
Authors: Alpat Safak , Alma Melih , Yılmaz Mustafa
Published: September 2024

Congenital mitral stenosis is a rare anomaly. We report successful surgical management of congenital mitral stenosis in a patient with Kabuki syndrome. A 15-month-old male with Kabuki syndrome was referred and echocardiography showed isolated congenital mitral stenosis. The valve was not repairable as it was showing severe stenotic features in multilevel fashion. Valve was replaced with mechanical valve. Postoperative course was uneventful without any rhythm problem and he has been doing well clinically during the 25 months follow-up with regular international normalized ratio checks.
Loan verb accommodation: a comparison of Old Norse and French in Middle English
Authors: ELTER W. JULIANE , SHAW MARLIEKE
Published: September 2024

Recent research shows that, even under direct insertion, loan verbs are subject to constraints: for instance, they enter non-finite categories more readily than finite categories. To deepen our understanding of such loan word accommodation biases we investigate two contact situations to test whether biases hold in contact between closely related languages. A corpus study on Norse and French loan verbs entering Middle English compares the proportions of their finite and non-finite usage to gauge the impact of etymology and temporal distance to direct contact on loan integration. We identify significant bias towards non-finite use for both etymologies, but it is stronger for French than for Norse loan verbs. This suggests that biases are stronger in some contexts than in others: they are more prominent at a smaller temporal distance to direct contact and in contact between languages that are less closely related.
Bilinguals show evidence of brain maintenance in Alzheimer's disease
Authors: Coulter Kristina , Phillips Natalie A. ,   the CIMA-Q and COMPASS-ND groups
Published: September 2024

We examined brain and cognitive reserve related to bilingualism in older adults with, or at-risk for, Alzheimer's disease (AD) from the Canadian Consortium on Neurodegeneration in Aging and the Quebec Consortium for the Early Identification of Alzheimer's Disease. We used surface-based morphometry methods to measure cortical thickness and volume of language-related and AD-related brain regions. We did not observe evidence of brain reserve in language-related regions. However, reduced hippocampal volume was observed for monolingual, but not bilingual, older adults with AD. Thus, bilingualism is hypothesized to contribute to reserve in the form of brain maintenance in the context of AD.
Effects of dominance on language switching: a longitudinal study of Turkish–Dutch children with and without developmental language disorder
Authors: Snijders Vera , van Witteloostuijn Merel , Boerma Tessel , Timmermeister Mona , Blom Elma
Published: September 2024

Bilinguals frequently switch between languages. The present study examined cued language switching (CLS) longitudinally in bilingual Turkish–Dutch children with (n = 11) and without (n = 30) developmental language disorder (DLD) in a three-wave design with one-year intervals. We studied effects of dominance, indexed by language proficiency and exposure, on overall switching performance and the costs associated with switching between languages. Results show limited evidence for overall costs associated with language switching (i.e., only mixing costs in reaction times [RTs]). Further, accuracy on CLS increased with increasing dominance in the trial language. Moreover, better performance, and larger switching costs, were found in the majority (Dutch) compared to the minority (Turkish) language. These results are discussed in light of the sociolinguistic context. As hypothesized, more errors, longer RTs and slightly larger mixing costs were observed in children with DLD, suggesting overall word retrieval difficulties and difficulties with cognitive control.
Hidden rule of law discontinuities: A theoretical framework for studying rule of law backsliding
Authors: Graver Hans Petter , Gyöngyi Petra
Published: September 2024

This introduction develops a theoretical framework for understanding authoritarian backsliding against the backdrop of existing historical and European socio-legal scholarship. It introduces a number of key distinctions to better understand socio-legal variance among autocratisation. Specifically, it highlights the distinction between authoritarian backsliding and complete breakdown of judicial independence and human rights

Authoritarian backsliding is an aggravated form of rule of law decay, where functioning of key rule of law institutions comes under direct threat and it is mostly observable in the contemporary Central and Eastern European context. This differs from historical instances of authoritarian turn referring to the complete breakdown of judicial independence and human rights, characterised by the politicisation of courts as a mainly historical phenomenon. The differentiation and their socio-legal implications is crucial for developing a roadmap to identify different forms of autocratisation and their different contexts (actors, institutional and political context) that need to be considered when addressing rule of law decay in Europe, both at the national and supranational levels. Ultimately, this general overview also offers the possibility to identify and address latent discontinuities in rule of law development at both the supranational and national levels. Identification of such latent discontinuities is of importance when assessing the risks involved in the introduction of emergency measures to combat perceived threats to the state and the society.
The many faces of sovereignty
Authors: Yoon Kate
Published: September 2024

Critiques of international economic law have attacked the tendency of transnational legal processes, including investor-state dispute settlement (ISDS), to undermine states' sovereignty. In response to these criticisms, many states have limited the power of investment tribunals by reasserting their sovereignty. There are reasons, however, to be critical of endorsing sovereignty, particularly in the context of global distributive inequalities. This is because assertions of sovereignty are normatively ambivalent in their effects: they can be used to entrench and naturalize the unequal assets held by each state, rather than to empower states to exercise their right to regulate. These potential tensions can be resolved if sovereignty is understood as a term that is used in many different ways. Critics of ISDS often conflate two distinct meanings of sovereignty: sovereignty understood as the right to be free from external influence, and sovereignty understood as states' right to regulate. Because states are constrained by differences in resources and capacity, withdrawing from ISDS cannot always secure the conditions for effective domestic regulation. Sovereignty understood as the right to be free from interference may even stand in the way of states' ability to regulate, by allowing states to gatekeep resources that were accumulated through historical injustice
ANSELM’S ONTOLOGICAL ARGUMENT AND GRADES OF BEING
Authors: McCARTY CHARLES
Published: September 2024

Anselm described god as “something than which nothing greater can be thought” [1, p. 93], and Descartes viewed him as “a supreme being” [7, p. 122]. I first capture those characterizations formally in a simple language for monadic predicate logic. Next, I construct a model class inspired by Stoic and medieval doctrines of grades of being [8, 20]. Third, I prove the models sufficient for recovering, as internal mathematics, the famous ontological argument of Anselm, and show that argument to be, on this formalization, valid. Fourth, I extend the models to incorporate a modality fit for proving that any item than which necessarily no greater can be thought is also necessarily real. Lastly, with the present approach, I blunt the sharp edges of notable objections to ontological arguments by Gaunilo and by Grant. A trigger warning: every page of this writing flouts the old saw “Existence is not a predicate” and flagrantly.
Accurate Global Atmospheric State Analysis Using Objective Error Statistics Including Observation Error Dependence on Water Substance Field
Authors: Ishibashi Toshiyuki
Published: September 2024

Atmospheric state analysis is a difficult scientific problem but essential for atmospheric sciences. Data assimilation can generate accurate analyses by integrating information on the atmospheric state using probability density functions (PDFs), where the Gaussian approximation is typically used and PDFs are described by error covariance matrices (ECMs). However, ECMs have been estimated empirically, and dependency of the ECMs on meteorological conditions (flow) is only partially represented. These limit atmospheric state analysis accuracy. This is especially problematic for water substance‐sensitive microwave radiances (WS‐MWRs) because of their strong flow dependence. We objectively estimated ECMs of all data including flow‐dependence of the ECMs of WS‐MWRs. Since the ECM of each data is a component of one ECM representing one joint PDF as a whole, it is theoretically better to objectively estimate ECMs of all data, not just a particular data. For WS‐MWRs, we categorized flow into four using water substance amount and estimating an ECM for each category. Numerical experiments using the new ECMs on an operational global numerical weather prediction system show the followings. The new error standard deviations are generally smaller than those of empirical. Standard deviations and interchannel correlations of observation errors of WS‐MWRs increase with water substance amount. The effects of WS‐MWRs on analysis were approximately doubled. The analysis fields differ systematically such as increase of low‐level clouds over cold oceans. The forecast accuracy improved with 95% statistical significance up to 9%. Both the flow dependence of correlation and variance of WS‐MWRs contributed to the improvement of forecast accuracy.
Ferric Iron Evolution During Crystallization of the Earth and Mars
Authors: Schaefer Laura , Pahlevan Kaveh , Elkins‐Tanton Linda T.
Published: September 2024

Magma ocean crystallization models that track fO2 evolution can reproduce the D/H ratios of both the Earth and Mars without the need for exogenous processes. Fractional crystallization leads to compositional evolution of the bulk oxide components. Recent work suggests that metal‐saturated magma oceans may contain near‐present‐day Fe3+ concentrations. We model the fractional crystallization of Earth and Mars, including Fe2+ and Fe3+ as separate components. We calculate Fe3+ partition coefficients for lower mantle minerals and compare the results of fractional crystallization for both Earth and Mars. We calculate oxygen fugacity (fO2) at the surface as the systems evolve and compare them to constraints on the fO2 of the last magma ocean atmosphere from D/H ratios, both with and without metal saturation. For Earth, we find that Fe3+ likely behaves incompatibly in the lower mantle in order to match the D/H constraint for whole mantle models, but shallow magma ocean models also provide reasonable matches. Disproportionation in whole mantle magma oceans likely overpredicts the amount of Fe3+ and metal that form or require subsequent reduction to return to present‐day values. For Mars, we cannot match the D/H constraints on last fO2 unless the magma ocean begins with <50% of the predicted Fe3+, but better match the present day mantle redox. We show that Fe3+ partitioning has a measurable effect on magma ocean redox, and that it evolves throughout the magma ocean's lifetime. We highlight the need for additional experimental constraints on ferric iron mineral/melt partitioning and more thermodynamic data for the Fe‐disproportionation reaction.
Environmental Health Assessment by Local Environmental Justice Experts for Evidence‐Based Decision‐Making in an Agricultural Community of Northern California
Authors: Aranda A. A. , Kelty J. S. , Manukian S. , Pardo E. , Jabbari K. , Schmidt R. J. , Dabritz H. A. , London J. K. , Van Winkle L. S. , Deeb‐Sossa N. ,   Knights Landing Promotoras
Published: September 2024

Environmental justice research driven by academics and policymakers often overlooks the valuable insights and leadership of the communities most impacted by environmental hazards. When institution‐led research approaches are employed, inadequate community ownership and limited institutional accountability hinder the effectiveness of environmental public health interventions. In contrast, a community‐owned and ‐managed approach to environmental justice research can guide community members in developing evidence‐based interventions. This paper outlines a community‐led environmental health assessment survey (sample = 100) and resulting community actions over 6 years (2017–2023) in a Northern California farmworker community with a perceived high prevalence of cancer and exposure to environmental hazards in households, neighborhoods, and job sites. Local resident experts in Knights Landing, CA, documented community risk factors and exposures in collaboration with interdisciplinary undergraduate and graduate student‐researchers. The survey instrument focused on environmental hazards identified by local resident experts including vehicular and agricultural pollution, occupational pesticide contact, and sun exposure. Survey findings highlighted the need for targeted interventions to reduce environmental health risks, such as academic outreach programs, county investments in public services, and community‐led mutual aid initiatives. Despite academic reservations about our non‐random sampling method and data collection by local resident experts, our project sparked substantial actions and investments with minimal personnel and financial resources. Local leaders working with student‐researchers developed more effective environmental public health interventions through a community‐owned and ‐managed approach that went beyond the efforts of local regulatory and research institutions.
Exploring an Underwater Volcano from 16,000 Kilometers Away
Authors: Scharping Nathaniel
Published: September 2024

Measurements of Hunga volcano’s crater continued for months after its 2022 eruption.
South Pacific Water Intrusion Into the Sub‐Thermocline Makassar Strait in the Winter of 2016–2017 Following a Super El Niño
Authors: Li Mingting , Yuan Dongliang , Gordon Arnold L. , Gruenburg Laura K. , Wang Dongxiao
Published: September 2024

The Makassar Strait throughflow (MST) is the major component of the Indonesian Throughflow (ITF), transferring Pacific water into the Indian Ocean. In our previous study, we identified a new zonal pathway, a. k.a. the North Equatorial Subsurface Current (NESC), which carried equatorial water into the MST sub‐thermocline (>300 m) in the summer 2016 following the 2015/16 El Niño. We now show continued strong southward MST in the sub‐thermocline during the winter of 2016–2017, with salinity higher than that in the summer 2016, due to direct South Pacific water intrusion into the Sulawesi Sea. The origin of the intrusion is identified from the New Guinea Coastal Undercurrent (NGCUC) and from an anomalous westward flow along 3°N in the western equatorial Pacific. The identified interannual variability of the western Pacific Ocean circulation is particularly strong in the winter following super El Niño events.
Mapping Los Angeles Basin Depth With Sp Converted Phases
Authors: Yang Yan , Clayton Robert W.
Published: September 2024

The depth of the Los Angeles (LA) basin is a critical factor for seismic hazard assessment and active tectonic studies. By analyzing S‐waves generated by earthquakes below the basin that convert to P‐waves at the sediment‐bedrock interface, we estimate the maximum depth of the LA basin to be 9 km. This estimate depends on the velocities within and below the basin, and the depth presented here is based on the latest community velocity model. To map the basin depth, we use two dense arrays: the Community Seismic Network, a dense network of low‐cost accelerometers in schools across LA region, and a basin‐wide node survey conducted in 2022, consisting of about 300 geophones deployed for a month. Utilizing differential travel times between direct S and Sp converted phases of local earthquakes, we produce a detailed depth map of the LA basin.
Precipitation of Auroral Electrons Accelerated at Very High Altitudes: Impact on the Ionosphere and a Possible Acceleration Mechanism
Authors: Imajo S. , Miyoshi Y. , Kazama Y. , Asamura K. , Shinohara I. , Shiokawa K. , Kasahara Y. , Kasaba Y. , Matsuoka A. , Wang S.‐Y. , Tam S. W. Y. , Chang T.‐F. , Wang B.‐J. , Jun C.‐W. , Teramoto M. , Kurita S. , Tsuchiya F. , Kumamoto A. , Saito K. , Hori T.
Published: September 2024

The Arase satellite observed the precipitation of monoenergetic electrons accelerated from a very high altitude above 32,000 km altitude on 16 September 2017. The event was selected in the period when the high‐angular resolution channel of the electron detector looked at pitch angles within ∼5° from the ambient magnetic field direction, and thereby was the first to examine the detailed distribution of electron flux near the energy‐dependent loss cone at such high altitudes. The potential energy below the satellite estimated from the observed energy‐dependence of the loss cone was consistent with the energy of the upgoing ion beams, indicating that ionospheric ions were accelerated by a lower‐altitude acceleration region. The accelerated electrons inside the loss cone carried a significant net field‐aligned current (FAC) density corresponding to ionospheric‐altitude FAC of up to ∼3μA/m2. Based on the anisotropy of the accelerated electrons, we estimated the height of the upper boundary of the acceleration region to be >∼2 RE above the satellite. The height distribution of the acceleration region below the satellite, estimated from the frequency of auroral kilometric radiation, was ∼4,000–13,000 km altitude, suggesting that the very‐high‐altitude acceleration region was separated from the lower acceleration region. Additionally, we observed time domain structure (TDS) electric fields on a subsecond time scale with a thin FAC indicated by magnetic deflections. Such a TDS may be generated by the formation of double layers in the magnetotail, and its potential drop could significantly contribute (∼40%–60%) to the parallel energization of precipitating auroral electrons.
Whistler‐Mode Waves Observed by the DEMETER Spacecraft and the Kannuslehto Station: Spatial Extent and Propagation to the Ground
Authors: Drastichová K. , Němec F. , Manninen J.
Published: September 2024

We use conjugate observations of magnetospheric whistler‐mode waves at frequencies up to 16 kHz by the DEMETER spacecraft (at an altitude of approximately 660 km) and the ground‐based Kannuslehto station in Finland to investigate the wave propagation to the ground and their characteristic spatial scales. For this purpose, we evaluate correlations between the wave intensities measured by the spacecraft and the ground‐based station at various frequencies as a function of their longitudinal and L‐shell separations. Two different approaches are used: (a) direct correlation of wave intensities measured at the same times and (b) correlation of wave intensities within corresponding frequency‐time windows, focusing on the identification of the same frequency‐time wave signatures. We show that the characteristic longitudinal scales of the investigated waves are between about and . We further demonstrate that, while the wave intensities measured by DEMETER are generally larger during periods of enhanced geomagnetic activity, wave intensities measured on the ground during increased activity are only slightly larger during the daytime and decrease during the nighttime.
The Role of α−β Quartz Transition in Fluid Storage in Crust From the Evidence of Electrical Conductivity
Authors: Hu Haiying , Yin Chuanyu , Dai Lidong , Lai Jinhua , Chen Yiqi , Wang Pengfei , Zhu Jinlong , Han Songbai
Published: September 2024

Aqueous fluids are extensively present in the middle to lower crust, as revealed by seismic and magnetotelluric soundings. The α−β quartz phase transition significantly affects many physical properties and leads to substantial microcracks that can provide pathways for the migration of crustal fluids. A systematic investigation of macroscopic physical properties and microstructure of quartz is crucial to elucidate their correlation. In the present study, the effects of water content, trace elements, orientations, and phase transition on the electrical conductivity of quartz were thoroughly evaluated at 400−900°C and 1 GPa. Individual annealing experiments were simultaneously conducted on quartz single crystals at different peak temperatures and 1 GPa to investigate the evolution and spatial distribution of microcracks using X‐ray microtomography (CT) and backscattered electron imaging. We found that trace element content and orientations, rather than H2O, are the dominant factors controlling the conductivity of quartz. The distinct changes in conductivity of single crystals at around α−β phase transition temperature are attributed to the transformation of microcracks from isolated to interconnected networks, as confirmed by two‐dimensional (2‐D) and three‐dimensional (3‐D) microstructure images. Based on the variation in electrical conductivity and microstructure across the transition, it thus is proposed that the intragranular microcracks caused by quartz phase transition can serve as fluid or melt pathways within highly conductive zones present in the middle to lower crust, while α‐quartz acts as an impermeable cap.
Mapping and Characterizing the Northern Fan Deposits in Jezero Crater, Mars
Authors: Jodhpurkar Mohini J. , Bell James F. , Gupta Sanjeev , Horgan Briony , Gwizd Samantha , Caravaca Gwénaël , Randazzo Nicolas
Published: September 2024

The northern inlet channel to Jezero crater (Sava Vallis) terminates in a fan‐shaped depositional feature, part of which blends into the separate well‐known western fan delta that is the field site for the Mars 2020 mission's Perseverance rover. Jezero's northern fan potentially represents either a second fan delta within the crater or a distal portion of the western fan. To constrain the fluvial and sedimentological history of Jezero and place the rover's in situ observations in proper geologic context, we photogeologically map the northern fan deposits at a larger mapping scale than previous studies, using ground‐based imaging from the Perseverance rover for context. Fifteen map units are identified using HiRISE‐based interpretations of geologic characteristics and inferred processes as well as crosscutting relative age relationships. Mapped units are also defined based on orbital data from CRISM and THEMIS to assess their compositional signatures. We interpret the northern fan deposits as older than the uppermost blocky unit in the western fan delta, suggesting that they were deposited contemporaneously with or prior to the deposition of the western fan, and under similar climate conditions. The eastern portion of the northern fan deposits shows evidence of fluvial deposition from Sava Vallis, while part of its western side could represent a distal part of the western fan delta. We synthesize our interpretations to present scenarios for the deposition of the northern and western fans, which can help constrain the history of both watersheds and place it into context within the broader Isidis basin region.
Increasing hexokinase 1 expression improves mitochondrial and glycolytic functional deficits seen in sporadic Alzheimer’s disease astrocytes
Authors: Bell Simon M. , Wareing Hollie , Capriglia Francesco , Hughes Rachel , Barnes Katy , Hamshaw Alexander , Adair Liam , Shaw Allan , Olejnik Alicja , De Suman , New Elizabeth , Shaw Pamela J. , De Marco Matteo , Venneri Annalena , Blackburn Daniel J. , Ferraiuolo Laura , Mortiboys Heather
Published: September 2024

Abnormalities in cellular metabolism are seen early in Alzheimer’s disease (AD). Astrocyte support for neuronal function has a high metabolic demand, and astrocyte glucose metabolism plays a key role in encoding memory. This indicates that astrocyte metabolic dysfunction might be an early event in the development of AD. In this paper we interrogate glycolytic and mitochondrial functional changes and mitochondrial structural alterations in patients’ astrocytes derived with a highly efficient direct conversion protocol. In astrocytes derived from patients with sporadic (sAD) and familial AD (fAD) we identified reductions in extracellular lactate, total cellular ATP and an increase in mitochondrial reactive oxygen species. sAD and fAD astrocytes displayed significant reductions in mitochondrial spare respiratory capacity, have altered mitochondrial membrane potential and a stressed mitochondrial network. A reduction in glycolytic reserve and glycolytic capacity is seen. Interestingly, glycolytic reserve, mitochondrial spare respiratory capacity and extracellular lactate levels correlated positively with neuropsychological tests of episodic memory affected early in AD. We identified a deficit in the glycolytic enzyme hexokinase 1 (HK1), and correcting this deficit improved the metabolic phenotype in sAD not fAD astrocytes. Importantly, the amount of HK1 at the mitochondria was shown to be reduced in sAD astrocytes, and not in fAD astrocytes. Overexpression of HK1 in sAD astrocytes increases mitochondrial HK1 levels. In fAD astrocytes HK1 levels were unaltered at the mitochondria after overexpression. This study highlights a clear metabolic deficit in AD patient-derived astrocytes and indicates how HK1, with its roles in both oxidative phosphorylation and glycolysis, contributes to this.