bluuebunny/crossref_metadata_2025 huggingface dataset:
Epilepsy syndromes in cerebral palsy: varied, evolving and mostly self-limited
Authors: Cooper Monica S , Mackay Mark T , Dagia Charuta , Fahey Michael C , Howell Katherine B , Reddihough Dinah , Reid Susan , Harvey A Simon
Published: July 2022

Seizures occur in approximately one-third of children with cerebral palsy. This study aimed to determine epilepsy syndromes in children with seizures and cerebral palsy due to vascular injury, anticipating that this would inform treatment and prognosis.

We studied a population-based cohort of children with cerebral palsy due to prenatal or perinatal vascular injuries, born 1999–2006. Each child’s MRI was reviewed to characterize patterns of grey and white matter injury. Children with syndromic or likely genetic causes of cerebral palsy were excluded, given their inherent association with epilepsy and our aim to study a homogeneous cohort of classical cerebral palsy. Chart review, parent interview and EEGs were used to determine epilepsy syndromes and seizure outcomes.

Of 256 children, 93 (36%) had one or more febrile or afebrile seizures beyond the neonatal period and 87 (34%) had epilepsy. Children with seizures were more likely to have had neonatal seizures, have spastic quadriplegic cerebral palsy and function within Gross Motor Function Classification System level IV or V. Fifty-six (60%) children with seizures had electroclinical features of a self-limited focal epilepsy of childhood; we diagnosed these children with a self-limited focal epilepsy-variant given the current International League Against Epilepsy classification precludes a diagnosis of self-limited focal epilepsy in children with a brain lesion. Other epilepsy syndromes were focal epilepsy—not otherwise specified in 28, infantile spasms syndrome in 11, Lennox–Gastaut syndrome in three, genetic generalized epilepsies in two and febrile seizures in nine. No epilepsy syndrome could be assigned in seven children with no EEG. Twenty-one changed syndrome classification during childhood. Self-limited focal epilepsy-variant usually manifested with a mix of autonomic and brachio-facial motor features, and occipital and/or centro-temporal spikes on EEG. Of those with self-limited focal epilepsy-variant, 42/56 (75%) had not had a seizure for >2 years. Favourable seizure outcomes were also seen in some children with infantile spasms syndrome and focal epilepsy-not otherwise specified. Of the 93 children with seizures, at last follow-up (mean age 15 years), 61/91 (67%) had not had a seizure in >2 years.

Children with cerebral palsy and seizures can be assigned specific epilepsy syndrome diagnoses typically reserved for normally developing children, those syndromes commonly being age-dependent and self-limited. Compared to typically developing children with epilepsy, self-limited focal epilepsy-variant occurs much more commonly in children with cerebral palsy and epilepsy. These findings have important implications for treatment and prognosis of epilepsy in cerebral palsy, and research into pathogenesis of self-limited focal epilepsy.
Neuroplasticity after upper-extremity rehabilitation therapy with sensory stimulation in chronic stroke survivors
Authors: Schranz Christian , Vatinno Amanda , Ramakrishnan Viswanathan , Seo Na Jin
Published: July 2022

This study investigated the effect of using subthreshold vibration as a peripheral sensory stimulation during therapy on cortical activity. Secondary analysis of a pilot triple-blinded randomized controlled trial. Twelve chronic stroke survivors underwent 2-week upper-extremity task-practice therapy. Half received subthreshold vibratory stimulation on their paretic wrist (treatment group) and the other half did not (control). EEG connectivity and event-related de-/resynchronization for the sensorimotor network during hand grip were examined at pre-intervention, post-intervention and follow-up. Statistically significant group by time interactions were observed for both connectivity and event-related spectral perturbation. For the treatment group, connectivity increased at post-intervention and decreased at follow-up. Event-related desynchronization decreased and event-related resynchronization increased at post-intervention, which was maintained at follow-up. The control group had the opposite trend for connectivity and no change in event-related spectral perturbation. The stimulation altered cortical sensorimotor activity. The findings complement the clinical results of the trial in which the treatment group significantly improved gross manual dexterity while the control group did not. Increased connectivity in the treatment group may indicate neuroplasticity for motor learning, while reduced event-related desynchronization and increased event-related resynchronization may indicate lessened effort for grip and improved inhibitory control. EEG may improve understanding of neural processes underlying motor recovery.
The fate of oceanic plateaus: subduction versus accretion
Authors: Yan Zhiyong , Chen Lin , Zuza Andrew V , Tang Jiaxuan , Wan Bo , Meng Qingren
Published: July 2022

Oceanic plateaus (or aseismic ridges) can be either subducted into the deep mantle, or accreted onto the overriding plate. Furthermore, some oceanic plateaus can change subduction mode from steep to flat-slab subduction. What factors control the fate of oceanic plateaus during subduction remain enigmatic. Here, we investigate the controls on these modes and their respective geological effects using 2-D thermomechanical simulations. We systematically examine the characteristics of an oceanic plateau (including crustal thickness and length), plateau-trench distance, convergence rate and eclogitization of the oceanic crust. Our models confirm that the size of the plateau and eclogitization are the main factors controlling the subduction characteristics. For the eclogite models, a relatively thin oceanic plateau (≤20 km thick) undergoes steep subduction, a moderate-scale plateau (25–30 km thick) favours flat-slab subduction and large-scale plateaus (≥35 km thick) are more susceptible to collide and accrete to the overriding upper plate. Eclogitization significantly reduces the formation chance and duration of flat-slab subduction. The switch from flat-slab to steep subduction occurs rapidly (<5 Ma), and the steepening occurs twice as fast as the flattening. The plateau-trench distance determines the location of the break-off, and shallow break-off (<300 km) of the frontal slab will significantly change the subduction pattern. Either fast convergence rates (≥8 cm yr−1) or overthrusting of the overriding plate promotes the formation of flat-slab subduction. The mode changed from flat-slab to steep subduction explains the landward migration of magmatism followed by a trenchward migration in Eastern China since the Mesozoic.
A graph-space optimal transport objective function based on q-statistics to mitigate cycle-skipping issues in FWI
Authors: da Silva S L E F , Karsou A , de Souza A , Capuzzo F , Costa F , Moreira R , Cetale M
Published: July 2022

Full-waveform inversion (FWI) is a powerful seismic imaging methodology to estimate geophysical parameters that honour the recorded waveforms (observed data), and it is conventionally formulated as a least-squares optimization problem. Despite many successful applications, least-squares FWI suffers from cycle skipping issues. Optimal transport (OT) based FWI has been demonstrated to be a useful strategy for mitigating cycle skipping. In this work, we introduce a new Wasserstein metric based on q-statistics in the context of the OT distance. In this sense, instead of the data themselves, we consider the graph of the seismic data, which are positive and normalized quantities similar to probability functions. By assuming that the difference between the graphs of the modelled and observed data obeys the q-statistics, we introduce a robust q-generalized graph-space OT objective function in the FWI context namely q-GSOT-FWI, in which the standard GSOT-FWI based on l2-norm is a particular case. To demonstrate how the q-GSOT-FWI deals with cycle skipping, we present two numerical examples involving 2-D acoustic wave-equation modelling. First, we investigate the convexity of q-GSOT objective function regarding different time-shifts, and, secondly, we present a Brazilian pre-salt synthetic case study, from a crude initial model which generates significant cycle-skipping seismic data. The results reveal that the q-GSOT-FWI is a powerful strategy to circumvent cycle skipping issues in FWI, in which our objective function proposal presents a smoother topography with a wider attraction valley to the optimal minimum. They also show that q-statistics leads to a significant improvement of FWI objective function convergence, generating higher resolution acoustic models than classical approaches. In addition, our proposal reduces the computational cost of calculating the transport plan as the q-value increases.
Source scaling comparison and validation in Central Italy: data intensive direct Swaves versus the sparse data coda envelope methodology
Authors: Morasca Paola , Bindi Dino , Mayeda Kevin , Roman-Nieves Jorge , Barno Justin , Walter William R , Spallarossa Daniele
Published: July 2022

Robustness of source parameter estimates is a fundamental issue in understanding the relationships between small and large events; however, it is difficult to assess how much of the variability of the source parameters can be attributed to the physical source characteristics or to the uncertainties of the methods and data used to estimate the values. In this study, we apply the coda method by Mayeda et al. using the coda calibration tool (CCT), a freely available Java-based code (https://github.com/LLNL/coda-calibration-tool) to obtain a regional calibration for Central Italy for estimating stable source parameters. We demonstrate the power of the coda technique in this region and show that it provides the same robustness in source parameter estimation as a data-driven methodology [generalized inversion technique (GIT)], but with much fewer calibration events and stations. The Central Italy region is ideal for both GIT and coda approaches as it is characterized by high-quality data, including recent well-recorded seismic sequences such as L'Aquila (2009) and Amatrice–Norcia–Visso (2016–2017). This allows us to apply data-driven methods such as GIT and coda-based methods that require few, but high-quality data. The data set for GIT analysis includes ∼5000 earthquakes and more than 600 stations, while for coda analysis we used a small subset of 39 events spanning 3.5 < Mw < 6.33 and 14 well-distributed broad-band stations. For the common calibration events, as well as an additional 247 events (∼1.7 < Mw < ∼5.0) not used in either calibration, we find excellent agreement between GIT-derived and CCT-derived source spectra. This confirms the ability of the coda approach to obtain stable source parameters even with few calibration events and stations. Even reducing the coda calibration data set by 75 per cent, we found no appreciable degradation in performance. This validation of the coda calibration approach over a broad range of event size demonstrates that this procedure, once extended to other regions, represents a powerful tool for future routine applications to homogeneously evaluate robust source parameters on a national scale. Furthermore, the coda calibration procedure can homogenize the Mw estimates for small and large events without the necessity of introducing any conversion scale between narrow-band measures such as local magnitude (ML) and Mw, which has been shown to introduce significant bias.
A model combining patchy saturation and moisture-induced elastic weakening with application to ultrasonic monitoring under varying water saturation
Authors: Geremia Davide , David Christian
Published: July 2022

Water is known to induce weakening on the static mechanical properties of rocks. However, injection-based operations such as EGS or EOR are commonly monitored through seismic methods involving dynamic moduli. It is therefore important to understand and quantify the effect of water-weakening on dynamic properties. In this study, we performed water injection tests on microporous carbonate rocks (two chalks from the Mons Basin) with ultrasonic monitoring of P-wave velocity and attenuation in order to observe the evolution of the rock moduli with varying water saturation. Our experimental results were interpreted through (i) a classical patchy saturation or PS model and (ii) the same model coupled with water weakening effect through modulus reduction induced by surface energy decrease induced by water in the fluid–rock system, called the WW-PS model. We show that the WW-PS model can better fit the experimental data than the PS model for both selected chalks, but also the previously published data for Sherwood sandstone. Therefore fluid–rock interaction needs to be taken into account when dealing with a fluid not in equilibrium with the host reservoir in fluid injection operations. An extension to reservoir scale modelling is proposed to emphasize the potential impact of water weakening at larger scales.
Global centroid moment tensor solutions in a heterogeneous earth: the CMT3D catalogue
Authors: Sawade Lucas , Beller Stephen , Lei Wenjie , Tromp Jeroen
Published: July 2022

For over 40 yr, the global centroid-moment tensor (GCMT) project has determined location and source parameters for globally recorded earthquakes larger than magnitude 5.0. The GCMT database remains a trusted staple for the geophysical community. Its point-source moment-tensor solutions are the result of inversions that model long-period observed seismic waveforms via normal-mode summation for a 1-D reference earth model, augmented by path corrections to capture 3-D variations in surface wave phase speeds, and to account for crustal structure. While this methodology remains essentially unchanged for the ongoing GCMT catalogue, source inversions based on waveform modelling in low-resolution 3-D earth models have revealed small but persistent biases in the standard modelling approach. Keeping pace with the increased capacity and demands of global tomography requires a revised catalogue of centroid-moment tensors (CMT), automatically and reproducibly computed using Green's functions from a state-of-the-art 3-D earth model. In this paper, we modify the current procedure for the full-waveform inversion of seismic traces for the six moment-tensor parameters, centroid latitude, longitude, depth and centroid time of global earthquakes. We take the GCMT solutions as a point of departure but update them to account for the effects of a heterogeneous earth, using the global 3-D wave speed model GLAD-M25. We generate synthetic seismograms from Green's functions computed by the spectral-element method in the 3-D model, select observed seismic data and remove their instrument response, process synthetic and observed data, select segments of observed and synthetic data based on similarity, and invert for new model parameters of the earthquake’s centroid location, time and moment tensor. The events in our new, preliminary database containing 9382 global event solutions, called CMT3D for ‘3-D centroid-moment tensors’, are on average 4 km shallower, about 1 s earlier, about 5 per cent larger in scalar moment, and more double-couple in nature than in the GCMT catalogue. We discuss in detail the geographical and statistical distributions of the updated solutions, and place them in the context of earlier work. We plan to disseminate our CMT3D solutions via the online ShakeMovie platform.
Error estimates for seismic body wave delay times in the ISC-EHB Bulletin
Authors: Nolet Guust , van der Lee Suzan
Published: July 2022

We analyse the consistency of the delay time data in the most recent version of the ISC-EHB bulletin published by the International Seismological Centre covering the years 1964–2018. Considering that the delays are influenced by the lateral heterogeneity in the Earth’s mantle, we construct a tomographic matrix. We use singular value decomposition of the tomographic matrix for 19 707 dense clusters of earthquakes to compute objective estimates of the standard error from data that project into the null space and should be zero if there were no errors. Using a robust initial estimate of the standard deviation of the clustered delay times, we remove a small fraction of outliers before calculating the ultimate errors. We found that the errors depend on the type of body wave, depth of the earthquake (crust or mantle) and the number of decimals with which the arrival time was reported. Using these parameters, we distinguish 45 different classes of delay times for 11 different types of body waves. The errors of each class so divided generally follow a distribution that is approximately normal with a mean that ranges from 0.32 s for PKPbc waves from mantle earthquakes, to 2.82 s for S waves from shallow earthquakes bottoming in the upper mantle. The widths of the distributions of the errors themselves are small enough to serve in formal statistical quantification of the quality of fit in tomographic experiments.
The SGNH hydrolase family: a template for carbohydrate diversity
Authors: Anderson Alexander C , Stangherlin Stefen , Pimentel Kyle N , Weadge Joel T , Clarke Anthony J
Published: July 2022

The substitution and de-substitution of carbohydrate materials are important steps in the biosynthesis and/or breakdown of a wide variety of biologically important polymers. The SGNH hydrolase superfamily is a group of related and well-studied proteins with a highly conserved catalytic fold and mechanism composed of 16 member families. SGNH hydrolases can be found in vertebrates, plants, fungi, bacteria, and archaea, and play a variety of important biological roles related to biomass conversion, pathogenesis, and cell signaling. The SGNH hydrolase superfamily is chiefly composed of a diverse range of carbohydrate-modifying enzymes, including but not limited to the carbohydrate esterase families 2, 3, 6, 12 and 17 under the carbohydrate-active enzyme classification system and database (CAZy.org). In this review, we summarize the structural and functional features that delineate these subfamilies of SGNH hydrolases, and which generate the wide variety of substrate preferences and enzymatic activities observed of these proteins to date.
Characterization of the interaction of multivalent glycosylated ligands with bacterial lectins by biolayer interferometry
Authors: Picault Léo , Laigre Eugénie , Gillon Emilie , Tiertant Claire , Renaudet Olivier , Imberty Anne , Goyard David , Dejeu Jerome
Published: July 2022

The study of multivalent carbohydrate–protein interactions remains highly complicated and sometimes rendered impossible due to aggregation problems. Biolayer interferometry is emerging as a tool to monitor such complex interactions. In this study, various glycoclusters and dendrimers were prepared and evaluated as ligands for lectins produced by pathogenic bacteria Pseudomonas aeruginosa (LecA and Lec B) and Burkholderia ambifaria (BambL). Reliable kinetic and thermodynamic parameters could be measured, and immobilization of either lectin or ligands resulted in high quality data. The methods gave results in full agreement with previous isothermal titration calorimetry experiments, and presented strong advantages because they require less quantity and purity for the biomolecules.
Mnt1, an α-(1 → 2)-mannosyltransferase responsible for the elongation of N-glycans and O-glycans in Aspergillus fumigatus
Authors: Kadooka Chihiro , Hira Daisuke , Tanaka Yutaka , Chihara Yuria , Goto Masatoshi , Oka Takuji
Published: July 2022

The fungal cell wall is necessary for survival as it serves a barrier for physical protection. Therefore, glycosyltransferases responsible for the synthesis of cell wall polysaccharides may be suitable targets for drug development. Mannose is a monosaccharide that is commonly found in sugar chains in the walls of fungi. Mannose residues are present in fungal-type galactomannan, O-glycans, N-glycans, glycosylphosphatidylinositol anchors, and glycosyl inositol phosphorylceramides in Aspergillus fumigatus. Three genes that are homologous to α-(1 → 2)-mannosyltransferase genes and belong to the glycosyltransferase family 15 were found in the A. fumigatus strain, Af293/A1163, genome: cmsA/ktr4, cmsB/ktr7, and mnt1. It is reported that the mutant ∆mnt1 strain exhibited a wide range of properties that included high temperature and drug sensitivity, reduced conidia formation, leakage at the hyphal tips, and attenuation of virulence. However, it is unclear whether Mnt1 is a bona fide α-(1 → 2)-mannosyltransferase and which mannose residues are synthesized by Mnt1 in vivo. In this study, we elucidated the structure of the Mnt1 reaction product, the structure of O-glycan in the Δmnt1 strain. In addition, the length of N-glycans attached to invertase was evaluated in the Δmnt1 strain. The results indicated that Mnt1 functioned as an α-(1 → 2)-mannosyltransferase involved in the elongation of N-glycans and synthesis of the second mannose residue of O-glycans. The widespread abnormal phenotype caused by the disruption of the mnt1 gene is the combined result of the loss of mannose residues from O-glycans and N-glycans. We also clarified the enzymatic properties and substrate specificity of Mnt1 based on its predicted protein structure.
Breastfeeding-related neck pain: prevalence and correlates among Nigerian lactating mothers
Authors: Ojukwu Chidiebele Petronilla , Okpoko Chinechendu Glory , Okemuo Adaora Justina , Ede Stephen Sunday , Ilo Ijeoma Judith
Published: July 2022

Background

Breastfeeding (BF) is a physically demanding task and is predominantly performed in a head-down position as the mother attempts to maintain eye contact with the infant. There are possibilities of BF-related neck pain (BFRNP) that have not been widely studied. This study investigated the prevalence and correlates of BFRNP in Nigerian lactating mothers.

Methods

A cross-sectional descriptive survey was conducted among 310 lactating mothers selected from post-natal clinics in Enugu, Nigeria. Information on their BF profile was sought as well as the prevalence and characteristics of BFRNP using a self-structured questionnaire.

Results

It was found that cradle hold was the commonly adopted BF position (94.0%) and the majority breastfed ≥10 times daily (55.2%) for <30 min per session (49.1%). BFRNP was seen in 51.7% of women, of which 55.0% reported moderate pain intensity and 60.0% experienced this pain during BF. None of the maternal characteristics and breastfeeding profiles were significantly associated with the prevalence of BFRNP (p>0.05).

Conclusions

There is a high prevalence of BFRNP among nursing mothers. Although maternal characteristics and BF positions were not associated with reported BFRNP, the results suggest that changing BF positions reduces neck pain during nursing sessions. Therefore this study recommends that nursing mothers should regularly change their BF positions to increase relaxation and comfort.
What Can a Critical Cybersecurity Do?
Authors: Dwyer Andrew C , Stevens Clare , Muller Lilly Pijnenburg , Cavelty Myriam Dunn , Coles-Kemp Lizzie , Thornton Pip
Published: July 2022

Cybersecurity has attracted significant political, social, and technological attention as contemporary societies have become increasingly reliant on computation. Today, at least within the Global North, there is an ever-pressing and omnipresent threat of the next “cyber-attack” or the emergence of a new vulnerability in highly interconnected supply chains. However, such discursive positioning of threat and its resolution has typically reinforced, and perpetuated, dominant power structures and forms of violence as well as universalist protocols of protection. In this collective discussion, in contrast, six scholars from different disciplines discuss what it means to “do” “critical” research into what many of us uncomfortably refer to as “cybersecurity.” In a series of provocations and reflections, we argue that, as much as cybersecurity may be a dominant discursive mode with associated funding and institutional “benefits,” it is crucial to look outward, in conversation with other moves to consider our technological moment. That is, we question who and what cybersecurity is for, how to engage as academics, and what it could mean to undo cybersecurity in ways that can reassess and challenge power structures in the twenty-first century.
Inking Wartime: Military Tattoos and the Temporalities of the War Experience
Authors: Palestrino Mirko
Published: July 2022

Military tattoos have recently become the latest genre of war art deployed by museums to make war tangible to their visitors. These new war objects give rise to important temporal inconsistencies: as individual soldiers relate different understandings of wartime, exhibitions mediate them monolithically, reproducing a notion of wartime as exceptional, finite, and temporary. To grasp this inconsistency, this article introduces a conceptual distinction between chronic and chronological embodied temporalities of war experience. In the four exhibitions of military tattoos under analysis, different veterans locate war's end at different junctures or moments. In these experiences, the issue of war's ending is a matter of chronology. In contrast, other veterans find war to be never-ending. In this case, war is akin to a chronic condition, whose very essence is a sense of temporal lingering that puts the idea of war's ending into question. I show that sticking to univocal understanding of wartime, exhibitions of military tattoos efface chronic and chronologically discrepant war experiences, contributing to the (re)production of a war/peace(time) binary that has been repeatedly deemed to be problematic and violent.
Public Opinion on Institutional Designs for the United Nations: An International Survey Experiment
Authors: Ghassim Farsan , Koenig-Archibugi Mathias , Cabrera Luis
Published: July 2022

Scholars and policy makers have intensely debated institutional reforms of the United Nations (UN) since its creation. Yet, relatively little attention has been given to institutional design preferences among the public in UN member states. This study examines two questions: Which possible rules concerning UN authority and representation do citizens prefer? Which personal and country characteristics are associated with their varying institutional preferences? A population-based conjoint survey experiment conducted in Argentina, China, India, Russia, Spain, and the United States is used to identify public preferences on nine distinct institutional design dimensions figuring prominently in UN reform debates. We find widespread support for increasing or at least maintaining UN authority over member states and for handing control over its decision-making to UN organs that would represent the citizens of every member state more directly. Citizens’ institutional preferences are associated with their political values and vary depending on whether their home countries would gain or lose influence from a specific reform.
Glee and Grievance: Emotive Events and Campaign Size in Nonviolent Resistance
Authors: Gledhill John , Duursma Allard , Shay Christopher
Published: July 2022

While scholars of nonviolent resistance recognize that large-scale campaigns are more likely to be successful campaigns, we currently have little understanding of why some nonviolent protests grow into mass movements while others do not. In this article, we explore campaign size and, in particular, the role of individual and collective motives in facilitating the growth of nonviolent campaigns. We start by assuming that, after campaign onset, barriers to growth emerge because some aggrieved individuals who are sympathetic to the cause are wary of incurring the (opportunity) costs of participating in campaign rallies. On occasion, we argue, organizers respond to this challenge by staging events that generate rewarding emotional experiences for participants and spectators, such as concerts, mass singing, or other collective expressive acts. Since the feelings of empowerment, solidarity, catharsis, or glee that accompany these events can only be enjoyed by those who are physically present at campaign rallies, the provision of such “emotive events” creates an individual-level incentive for passive supporters to mobilize. As this incentive attracts new participants, campaigns can grow—potentially into large-scale phenomena. To assess the plausibility of our argument, we code original data on emotive events and investigate whether the provision of such events in the course of nonviolent campaigns is associated with the size and scale of those campaigns. Finding this to be the case, we conclude that campaigns that are more creative, humorous, cathartic, and/or fun are also more likely to be large-scale campaigns.
Citizens to Soldiers: Mobilization, Cost Perceptions, and Support for Military Action
Authors: Blankshain Jessica D , Cohn Lindsay P , Kriner Douglas L
Published: July 2022

Policymakers have long assumed, and scholars have long argued, that how a government raises military manpower affects public support for military action through two obvious mechanisms: the likelihood any given individual will be personally affected by the conflict, and the expected aggregate cost of the conflict. Increased costs are thought to cause the public to be more critical of the use of military force. But do they? We gain leverage on this question in the US context by employing a survey experiment that allows us both to compare reactions to a range of manpower policies—an all-volunteer standing force, conscription, and mobilization of the reserves—and to explicitly test multiple mechanisms—expectations of bearing personal cost, expectations of aggregate cost, and effects not explained by these cost expectations. Our results strongly suggest that manpower policies’ effects are not straightforward. Consistent with previous studies, we find that an expectation of conscription lowers public support for military action. Mobilization of the reserves, however, fails to diminish support, despite the fact that it should also affect more people and signal a larger conflict. While casualty estimates (proxy for scale) are negatively correlated with mission support, personal cost expectations are not. Furthermore, much of the variation between manpower treatments is not explained by either tested cost mechanism, suggesting a role for norms and values. These findings have implications for whether military manpower policies designed to impose political costs on policymakers are likely to work and for wider discussions of public support for military operations.
Defense Contractors, Private Equity Firms, and US National Security
Authors: Mahoney Charles W , Tkach Benjamin K , Rethmeyer Craig J
Published: July 2022

Private equity firms have become important financial actors in the US defense industry in recent years—acquiring over 500 defense contractors since the early 2000s. This inquiry describes how increased capital flows into private equity funds, rising national security budgets, Pentagon policy, and rapid industry consolidation have spurred private equity investment in the businesses of American defense. Subsequently, the study demonstrates two ways private equity acquisitions of corporations in the defense industry affect US national security. First, because private equity firms often fund acquisitions through leveraged buyouts, the debt obligations of private equity–owned defense contractors are characterized by a relatively high risk of credit default. Second, the debt burden private equity firms place on defense contractors often reduces these companies’ free cash flow. As an increasing number of defense contractors are acquired by private equity firms, aggregate corporate reinvestment in the defense industry may well decline, thus diminishing the ability of contractors to perform their national security obligations.

entreprises du secteur de la défense sociétés de capital-investissement et sécurité nationale aux états-unis
Adjusting the bow-tie: a morpho-kinematic study of NGC 40
Authors: Rodríguez-González J B , Toalá J A , Sabin L , Ramos-Larios G , Guerrero M A , López J A , Estrada-Dorado S
Published: July 2022

We present a comprehensive study of the ionization structure and kinematics of the planetary nebula (PN) NGC 40 (a.k.a. the Bow-tie Nebula). A set of narrow-band images obtained with the Alhambra Faint Object Spectrograph and Camera at the Nordic Optical Telescope are used to study the turbulent distribution of gas in the main cavity, the ionization stratification and the density of this PN. High-resolution Manchester Echelle Spectrograph observations obtained at 2.1m telescope of the San Pedro Mártir Observatory are used to unveil in great detail the kinematic signatures of all morphological features in NGC 40. The images and spectra suggest that NGC 40 had multiple mass ejections in its recent formation history. We found 4 jet-like ejections not aligned with the main axis of NGC 40 (PA = 20°), some of them having pierced the main cavity along the SW–NE direction as well as the southern lobe. Using a tailor-made morpho-kinematic model of NGC 40 produced with shape, we found that the main cavity has a kinematic age of 6500 yr and the two pairs of lobes expanding towards the N and S directions have an averaged age of 4100 ± 550 yr. NGC 40 thus adds to the group of PNe with multiple ejections along different axes that challenge the models of PN formation.
Heat storage in ocean worlds: The role of slurries
Authors: Prieto-Ballesteros Olga , Muñoz-Iglesias Victoria , Bonales Laura J
Published: July 2022

Several icy moons of the Solar system, such as Europa, harbor global oceans below their surfaces. It is conceivable that a number of exoplanetary bodies may also possess them. The presence of aqueous layers, partially or totally liquid, highly influences the bulk physical properties of these bodies, particularly the thermal state, and consequently, the geological activity and the potential habitability over time. In this work, we obtained experimental data to characterize the thermal budgets of aqueous environments in planetary bodies depending on the main solute composition, and we quantified the heat associated with water-rich materials’ phase transitions occurring during planetary evolution. We measured the heat capacity (Cp) and the sensible heat values of aqueous systems at several concentrations of sulfate, carbonate, chloride, ammonia, and methanol at low temperatures, and we calculated the latent heat associated with the phase transitions. Raman spectroscopy allowed us to identify the phases related to the Cp and enthalpy (ΔH) variations. We applied thermal functions to estimate the energy involved in the generation of oceans and other endogenous processes, recognizing the impact of heat transfer by both ice and brine slurries. Likewise, we calculated the heat associated with the formation of local liquid lenses, particularly below Europa’s surface, which is suggested by the presence of geological features such as Thera Macula. We propose that the calorimetric properties of the slurries of the studied salt- and volatile-systems may sustain the potential habitability of icy moons and support the formation of certain surface features, in particular due to the high latent heat density and the promotion of the exothermic local growth of ice blocks that can separate from the remaining liquid.
Detection of spicules termed rapid blueshifted excursions as seen in the chromosphere via H α and the transition region via Si iv 1394 Å line emission
Authors: Vilangot Nhalil Nived , Shetye Juie , Doyle J Gerry
Published: July 2022

We show signatures of spicules termed rapid blueshifted excursions (RBEs) in the Si iv 1394 Å emission line using a semi-automated detection approach. We use the H α filtergrams obtained by the CRISP imaging spectropolarimeter on the Swedish 1-m Solar Telescope and co-aligned Interface Region Imaging Spectrograph data using the SJI 1400 Å channel to study the spatiotemporal signature of the RBEs in the transition region. The detection of RBEs is carried out using an oriented coronal loop tracing algorithm on H α Dopplergrams at ±35 km s−1. We find that the number of detected features is significantly impacted by the time-varying contrast values of the detection images, which are caused by the changes in the atmospheric seeing conditions. We detect 407 events with lifetime greater than 32 s. This number is further reduced to 168 RBEs based on the H α profile and the proximity of RBEs to the large-scale flow. Of these 168 RBEs, 89 of them display a clear spatiotemporal signature in the SJI 1400 Å channel, indicating that a total of $\sim 53{{\ \rm per\ cent}}$ are observed to have co-spatial signatures between the chromosphere and the transition region.
Tracing Milky Way scattering by compact extragalactic radio sources
Authors: Koryukova T A , Pushkarev A B , Plavin A V , Kovalev Y Y
Published: July 2022

We used archival very long baseline interferometry (VLBI) data of active galactic nuclei (AGN) observed from 1.4 to 86 GHz to measure the angular size of VLBI radio cores in 8959 AGNs. We analysed their sky distributions, frequency dependencies, and created the most densely sampled and complete to date distribution map of large-scale scattering properties of the interstellar medium in our Galaxy. Significant angular broadening of the measured AGN core sizes is detected for the sources seen through the Galactic plane, and this effect is especially strong at low frequencies (e.g. at 2 GHz). The scattering screens containing electron density fluctuations of hot plasma are mainly concentrated in the Galactic plane and manifest clumpy distribution. The region of the strongest scattering is the Galactic centre, where the Galactic bar and the compact radio source Sagittarius A* are located. We have also found the enhancement of scattering strength in regions of the Cygnus constellation, supernova remnants Taurus A, Vela, W78 and Cassiopeia A, and the Orion Nebula. Using multifrequency observational data of AGN core sizes, we separated the contribution of the intrinsic and scattered sizes to the measured angular diameter for 1411 sources. For the sources observed through the Galactic plane, the contribution of the scattered size component is systematically larger than for those seen outside the Galactic plane. The derived power-law scattering indices are found to be in good agreement with theoretical predictions for the diffractive-dominated scattering of radio emission in a hot plasma with Gaussian distribution of density inhomogeneities.
The prevalence of galaxy overdensities around UV-luminous Lyman 𝛼 emitters in the Epoch of Reionization
Authors: Leonova E , Oesch P A , Qin Y , Naidu R P , Wyithe J S B , de Barros S , Bouwens R J , Ellis R S , Endsley R M , Hutter A , Illingworth G D , Kerutt J , Labbé I , Laporte N , Magee D , Mutch S J , Roberts-Borsani G W , Smit R , Stark D P , Stefanon M , Tacchella S , Zitrin A
Published: July 2022

Before the end of the Epoch of Reionization, the Hydrogen in the Universe was predominantly neutral. This leads to a strong attenuation of Ly α lines of z ≳ 6 galaxies in the intergalactic medium. Nevertheless, Ly α has been detected up to very high redshifts (z ∼ 9) for several especially UV luminous galaxies. Here, we test to what extent the galaxy’s local environment might impact the Ly α transmission of such sources. We present an analysis of dedicated Hubble Space Telescope (HST) imaging in the CANDELS/EGS field to search for fainter neighbours around three of the most UV luminous and most distant spectroscopically confirmed Ly α emitters: EGS-zs8-1, EGS-zs8-2, and EGSY-z8p7 at zspec = 7.73, 7.48, and 8.68, respectively. We combine the multiwavelength HST imaging with Spitzer data to reliably select z ∼ 7–9 galaxies around the central, UV-luminous sources. In all cases, we find a clear enhancement of neighbouring galaxies compared to the expected number in a blank field (by a factor ∼3–9×). Our analysis thus reveals ubiquitous overdensities around luminous Ly α emitting sources in the heart of the cosmic reionization epoch. We show that our results are in excellent agreement with expectations from the Dragons simulation, confirming the theoretical prediction that the first ionized bubbles preferentially formed in overdense regions. While three UV luminous galaxies already have spectroscopic redshifts, the majority of the remaining fainter, surrounding sources are yet to be confirmed via spectroscopy. JWST follow-up observations of the neighbouring galaxies identified here will thus be needed to confirm their physical association and to map out the ionized regions produced by these sources.
Universal relations for rapidly rotating cold and hot hybrid stars
Authors: Khosravi Largani Noshad , Fischer Tobias , Sedrakian Armen , Cierniak Mateusz , Alvarez-Castillo David E , Blaschke David B
Published: July 2022

Several global parameters of compact stars are related via empirical relations, which are (nearly) independent of the underlying equation of state (EoS) of dense matter and, therefore, are said to be universal. We investigate the universality of relations that express the maximum mass and the radius of non-rotating and maximally rapidly rotating configurations, as well as their moment of inertia, in terms of the compactness of the star. For this, we first utilize a collection of cold (zero-temperature) and hot (isentropic) nucleonic EoS and confirm that the universal relations are holding for our collection of EoS. We then go on, to add to our collection and test for the same universality models of EoS that admit a strong first-order phase transition from nucleonic to deconfined quark matter. Also in this case we find that the universal relations hold, in particular for hot, isentropic hybrid stars. By fitting the universal relations to our computed data, we determine the coefficients entering these relations and the accuracy to which they hold.
vKompth: a variable Comptonization model for low-frequency quasi-periodic oscillations in black hole X-ray binaries
Authors: Bellavita Candela , García Federico , Méndez Mariano , Karpouzas Konstantinos
Published: July 2022

Low-mass X-ray binaries (LMXBs) show strong variability over a broad range of time-scales. The analysis of this variability, in particular of the quasi-periodic oscillations (QPO), is key to understanding the properties of the innermost regions of the accretion flow in these systems. We present a time-dependent Comptonization model that fits the energy-dependent rms-amplitude and phase-lag spectra of low-frequency QPOs in black hole (BH) LMXBs. We model the accretion disc as a multitemperature blackbody source emitting soft photons that are then Compton upscattered in a spherical corona, including feedback of Comptonized photons that return to the disc. We compare our results with those obtained with a model in which the seed-photons source is a spherical blackbody: at low energies, the time-averaged, rms, and phase-lag spectra are smoother for the disc-blackbody than for a blackbody, while at high energies both models give similar spectra. In general, we find that the rms increases with energy, the slope of the phase-lag spectrum depends strongly on the feedback, while the minimum-lag energy is correlated with the disc temperature. We fit the model to a 4.45-Hz type-B QPO in the BH LMXB MAXI J1438–630 and find statistically better fits and more compatible parameters with the steady-state spectrum than those obtained with a blackbody seed-photons source. Furthermore, we successfully apply the model to the type-C QPO in the BH LMXB GRS 1915 + 105, and thus conclude that this variable-Comptonization model reproduces the rms and phase-lags of both type B and C low-frequency QPOs in BH LMXBs.
Paving the way forEuclid and JWST via probabilistic selection of high-redshift quasars
Authors: Nanni Riccardo , Hennawi Joseph F , Wang Feige , Yang Jinyi , Schindler Jan-Torge , Fan Xiaohui
Published: July 2022

We introduce a probabilistic approach to select 6 ≤ $z$ ≤ 8 quasar candidates for spectroscopic follow-up, which is based on density estimation in the high-dimensional space inhabited by the optical and near-infrared photometry. Densities are modelled as Gaussian mixtures with principled accounting of errors using the extreme deconvolution (XD) technique, generalizing an approach successfully used to select lower redshift ($z$ ≤ 3) quasars. We train the probability density of contaminants on 1902 071 7-d flux measurements from the 1076 deg2 overlapping area from the Dark Energy Camera Legacy Survey (DECaLS) ($z$), VIKING (YJHKs), and unWISE (W1W2) imaging surveys, after requiring they dropout of DECaLS g and r, whereas the distribution of high-$z$ quasars are trained on synthetic model photometry. Extensive simulations based on these density distributions and current estimates of the quasar luminosity function indicate that this method achieves a completeness of $\ge 56{{\ \rm per\ cent}}$ and an efficiency of $\ge 5{{\ \rm per\ cent}}$ for selecting quasars at 6 < $z$ < 8 with JAB < 21.5. Among the classified sources are 8 known 6 < $z$ < 7 quasars, of which 2/8 are selected suggesting a completeness $\simeq 25{{\ \rm per\ cent}}$, whereas classifying the 6 known (JAB < 21.5) quasars at $z$ > 7 from the entire sky, we select 5/6 or a completeness of $\simeq 80{{\ \rm per\ cent}}$. The failure to select the majority of 6 < $z$ < 7 quasars arises because our quasar density model is based on an empirical quasar spectral energy distribution model that underestimates the scatter in the distribution of fluxes. This new approach to quasar selection paves the way for efficient spectroscopic follow-up of Euclid quasar candidates with ground-based telescopes and James Webb Space Telescope.
Substructure detection reanalysed: dark perturber shown to be a line-of-sight halo
Authors: Sengül Atinç Çagan , Dvorkin Cora , Ostdiek Bryan , Tsang Arthur
Published: July 2022

Observations of structure at subgalactic scales are crucial for probing the properties of dark matter, which is the dominant source of gravity in the universe. It will become increasingly important for future surveys to distinguish between line-of-sight haloes and subhalos to avoid wrong inferences on the nature of dark matter. We reanalyse a subgalactic structure (in lens JVAS B1938 + 666) that has been previously found using the gravitational imaging technique in galaxy-galaxy lensing systems. This structure has been assumed to be a satellite in the halo of the main lens galaxy. We fit the redshift of the perturber of the system as a free parameter, using the multiplane thin-lens approximation, and find that the redshift of the perturber is $z_\mathrm{int} = 1.42^{+0.10}_{-0.15}$ (with a main lens redshift of z = 0.881). Our analysis indicates that this structure is more massive than the previous result by an order of magnitude. This constitutes the first dark perturber shown to be a line-of-sight halo with a gravitational lensing method.