bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reproductive biology and placentotrophic embryonic development of the smalleye smooth-hound shark, Mustelus higmani, from the south-eastern Caribbean
Authors: Macías-Cuyare Marioxis , Tavares Rafael , Oddone Maria Cristina 
Published: December 2020

AbstractThe reproductive biology and embryonic development of Mustelus higmani were examined between January 2015 and December 2016 in the south-eastern Caribbean. Captures comprised 813 females (23.2–72.5 cm TL), and 960 males (22.6–62.5 cm TL). The total length at 50% maturity was estimated as 47.8 and 47.5 cm for females and males, respectively. Uterine fecundity ranged from 1 to 8 embryos and ovarian fecundity between 1 and 9 vitellogenic follicles. The time of parturition and mating season of M. higmani may occur throughout the year, peaking between November and February. The presence of pre-ovulatory ovarian follicles along with advanced embryos indicates an annual reproductive cycle for female M. higmani. The main embryonic development stages were recorded in the samples, from uterine eggs (1 to 6 per female) to term embryos (23.0–26.0 cm TL). The transition between placental pre-implantation and post-implantation occurs when embryos have attained a TL of 5.0–6.0 cm. The observation of abundant uterine histotrophic secretions in late pregnant and post-partum females demonstrates that histotrophy may intensify close to birth in this species. The local population of M. higmani appears to have relatively high productivity; nonetheless, this species is heavily harvested and lacks management measures in the study area.
Understanding the dynamics of lion attacks on humans and livestock in southern Maasailand, Kenya
Authors: Western Guy , Macdonald David W. , Loveridge Andrew J. , Dickman Amy J. , Tyrrell Peter , Russell Samantha 
Published: December 2020

Abstract
Negative interactions with humans resulting from livestock predation is a major factor influencing the decline of African lion Panthera leo populations across Africa. Here we investigate lion depredation within two Maasai communities in southern Kenya where people and lions coexist in the absence of any formal protected areas. We explore the factors that increase the frequency and severity of lion attacks on pastoralists and their livestock and assess the effectiveness of livestock guarding to reduce damage. Finally, we examine in which circumstances lion depredation triggers retaliation by people. Over a period of 26 months, lions attacked livestock 29 times, resulting in 41 livestock deaths and 19 injuries. There were also two attacks on people. Lions preferred cattle over the more numerous sheep and goats. Attacks on livestock occurred mostly during the dry season and were not affected by changes in prey density or variation in pastoral settlement that brought livestock into closer proximity with lions. Livestock were guarded during 48.2% of lion attacks. Active guarding at pasture disrupted the majority of lion attacks, resulting in lower mortality rates. Passive guarding in corrals at night also disrupted attacks but did not lead to lower livestock mortality.
Bilingual language experience as a multidimensional spectrum: Associations with objective and subjective language proficiency
Authors: Gullifer Jason W. , Kousaie Shanna , Gilbert Annie C. , Grant Angela , Giroud Nathalie , Coulter Kristina , Klein Denise , Baum Shari , Phillips Natalie , Titone Debra 
Published: December 2020

AbstractDespite the multifactorial space of language experience in which people continuously vary, bilinguals are often dichotomized into ostensibly homogeneous groups. The timing of language exposure (age of acquisition) to a second language (L2) is one well-studied construct that is known to impact language processing, cognitive processing, and brain organization, but recent work shows that current language exposure is also a crucial determinant in these domains. Critically, many indices of bilingual experience are inherently subjective and based on self-report questionnaires. Such measures have been criticized in favor of objective measures of language ability (e.g., naming ability or verbal fluency). Here, we estimate the bilingual experience jointly as a function of multiple continuous aspects of experience, including the timing of language exposure, the amount of L2 exposure across communicative contexts, and language entropy (a flexible measure of language balance) across communicative contexts. The results suggest that current language exposure exhibits distinct but interrelated patterns depending on the socio-experiential context of language usage. They also suggest that, counterintuitively, our sample more accurately self-assesses L2 proficiency than native language proficiency. A precise quantification of the multidimensional nature of bilingualism will enhance the ability of future research to assess language processing, acquisition, and control.
Characterising older adults’ engagement in age-friendly community initiatives: perspectives from core group leaders in the Northeast United States of America
Authors: Greenfield Emily A. , Reyes Laurent 
Published: December 2020

AbstractResearchers and programme champions alike have identified older adults as key contributors to age-friendly community change efforts. There has been very little scholarship, however, to characterise the nature of older adults’ engagement in age-friendly community initiatives (AFCIs). To help address this gap, we drew on five waves of data from semi-structured interviews with core group members of eight AFCIs in a Northeast region of the United States of America. Interviews were conducted as part of a multi-year, community-engaged study on the development of philanthropically supported AFCIs. We iteratively coded segments of the interviews in which core group members described the involvement of older adults, as well as their efforts to engage older adults in the initiatives. This analysis resulted in an inductive-analytic typology with five qualitatively distinct categories, including older adults as: (a) consumers (receiving information, goods and services through the AFCI), (b) informants (sharing perspectives on ageing in the community with the core group), (c) task assistants (assisting with project-oriented tasks under the direction of the core group), (d) champions (contributing ideas and implementing action on their own initiative), and (e) core group members (holding primary responsibility for driving the work of the AFCI forward). We discuss implications of the typology for research on AFCI implementation and evaluation, as well as opportunities for AFCIs to enhance the engagement of older adults from historically marginalised groups.
Variation in adjunct islands: The case of Norwegian
Authors: Bondevik Ingrid , Kush Dave , Lohndal Terje 
Published: December 2020

AbstractFinite adjunct clauses are often assumed to be among the strongest islands for filler–gap dependency creation cross-linguistically, but Kush, Lohndal & Sprouse (2019) found experimental evidence suggesting that finite conditionalom-adjunct clauses are not islands for topicalization in Norwegian. To investigate the generality of these findings, we ran three acceptability judgment experiments testing topicalization out of three adjunct clause types:om‘if’,når‘when’ andfordi‘because’ in Norwegian. Largely replicating Kush et al. (2019), we find evidence for the absence of strong island effects with topicalization fromom-adjuncts in all three experiments. We find island effects fornår- andfordi-adjuncts, but the size of the effects and the underlying judgment distributions that produce those effects differ greatly by island type. Our results suggest that the syntactic category ‘adjunct’ may not constitute a suitably fine-grained grouping to explain variation in island effects.
Teaching about Oppression and Rebellion: The “Peasants Are Revolting” Game
Authors: Asal Victor , Willis Charmaine , Linebarger Christopher , Jahanbani Nakissa 
Published: December 2020

ABSTRACTJean Jacques Rousseau wrote that “Man is born free, but is everywhere in chains.” Whereas the former claim of the quote is contestable and gendered, the latter part is empirically true from slavery to economic exploitation and widespread oppression that occurs to this day. Nevertheless, history shows that rarely will people take up weapons and rebel against the powerful. We have found that students often do not understand why this should be the case, given the rights that all people deserve. We use the Peasant Game exercise in class to shine a light on why most people, most of the time, endure repression and choose not to rebel. The game is played in turns with some students as lords, who decide how “food” will be apportioned, and other students as peasants, who produce the food. We discuss how power differentials occur and the difference they make. Students who play the game come away with a better understanding of why many people decide not to fight back against oppression—even if it is the right thing to do.
The Cosmic Timeline of Heliophysics: A Declaration of Significance
Authors: Moore Thomas Earle 
Published: December 2020

Key Points

The domain of Heliophysics, within the heliosphere, is complementary to the domain of Astrophysics, but can be studied directly by in situ probes
The domain of Heliophysics is uniquely distinguished from that of Astrophysics by the presence of living things
Heliophysics should expand its temporal horizon from that of practical meteorology and space weather to a climate evolution perspective
Quantifying the Effect of Magnetic Field Line Curvature Scattering on the Loss of Ring Current Ions
Authors: Eshetu W. W. , Tu W. , Jordanova V. K. , Cowee M. 
Published: December 2020

AbstractDuring geomagnetic storms, the ring current ions sometimes exhibit rapid loss as suggested by the fast recovery of the Dst index on a time scale of a few hours. The effects of magnetic field line curvature (FLC) scattering on the loss of ring current ions, which have not been well quantified, are studied here by test particle simulations under the T89c magnetic field model. Our simulation results show that the prediction of ion loss based on a single‐value cutoff of the κ parameter or maximum of of a single FLC scattering is not accurate. Instead, the e‐folding lifetime (τ) for the loss of ring current ions due to cumulative FLC scattering has been calculated for different initial ion energies, equatorial pitch angles, and L shells under different geomagnetic conditions. The results show that in general the FLC scattering loss is faster for ions of higher energy, higher mass, smaller pitch angle, higher L, and at high Kp level. Specifically, we find that at Kp = 6 the lifetime can be <10 h at L > 5 for 100 s keV protons and at L > 4 for 100 s keV O+, which demonstrates that FLC scattering can be an important mechanism for the observed fast loss (τ < 10 h) of ring current ions during geomagnetic storms. Furthermore, we formulate an empirical formula for τ as a function of ion energy, pitch angle, position, species, and Kp. The empirical formula can be directly included in ring current models to account for the FLC scattering effects.
A Systematic Approach to Mapping Regimes of Earthquake‐Induced Static Stress Changes Acting on Magmatic Pathways
Authors: Jenkins A. P. , Biggs J. , Rust A. C. , Jara R. L. 
Published: December 2020

AbstractLarge earthquakes alter the crustal stress field across great distances (hundreds to thousands of kilometers) over geologically short timescales (seconds to years). These stress changes can affect magmatic systems, triggering (or suppressing) volcanic unrest and eruption, along with other deeper processes. We use simple kinematic source models in an isotropic elastic half‐space to assess earthquake‐induced static stress changes (>1 kPa) over the entire thickness of the lithosphere and consider the implications for magma ascent and storage. Modeling subduction zone earthquakes, we calculate static normal stress changes with depth on three mutually perpendicular end‐member magma pathways: vertical arc‐parallel, vertical arc‐perpendicular, and horizontal. From this, we define seven stress change regimes within the adjacent volcanic arc. Three of these regimes may strongly encourage magma ascent in dykes by inducing unclamping (decreased compressive normal stress) of vertical pathways which increases in magnitude toward the surface and clamping of horizontal pathways. Two of the regimes may encourage stalling and storage of magma in sills near the base of the crust by inducing unclamping of horizontal pathways at depth. The spatial distribution of the regimes is largely dependent on earthquake magnitude, but also varies with slip distribution and interface dip. We show how the responses of magmatic systems to earthquakes also depends on the stress change magnitude and the state of the magmatic system, with a greater impact expected for larger stress changes acting on weaker, more thermally mature systems.
Stress Promotion of the 1958 Mw∼7.8 Fairweather Fault Earthquake and Others in Southeast Alaska by Glacial Isostatic Adjustment and Inter‐earthquake Stress Transfer
Authors: Rollins Chris , Freymueller Jeffrey T. , Sauber Jeanne M. 
Published: December 2020

AbstractWe assess how recent glacial isostatic adjustment (GIA) and inter‐earthquake stress transfer modulated the state of stress on major faults in Southeast Alaska, and how these effects may have influenced recent large and moderate earthquakes. The Glacier Bay Icefield has lost >3,000 km3 of ice since ca. 1770, with ice thinning up to 1.5 km, and the rest of southeast Alaska has been deglaciating since ca. 1900. The resulting GIA response in the solid earth produces present‐day surface uplift rates of up to ∼4 cm/yr, among the fastest on Earth. This rapid deformation occurs directly alongside and atop the Fairweather Fault, which accommodates 4–5 cm/yr of right‐lateral motion through slip in frequent large earthquakes, recently including a Mw∼7.8 earthquake in 1958. We find that the 1958 earthquake nucleated very close to the location of maximum GIA‐induced Coulomb stress increase on the Fairweather Fault between 1770 and 1958 (estimated at ∼0.2–0.6 MPa), on the only section of fault where GIA‐induced stress changes had involved both right‐lateral shearing and unclamping. The September 10, 1899 Mw∼8.1 Yakutat Bay earthquake also promoted failure on at least the northwest part of the eventual 1958 rupture. In turn, the 1899 and 1958 earthquakes and GIA promoted failure along the St. Elias compressional margin, the site of a Mw∼7.4 event in 1979. While rapid tectonic loading is very likely the main driver of earthquakes in southeast Alaska, we estimate that 23 of 30 instrumentally constrained Mw ≥ 5.0 earthquakes in this region were also promoted by post‐1770 GIA.
Does Deep Tectonic Tremor Occur in the Central‐Eastern Mediterranean Basin?
Authors: Bocchini G. M. , Martínez‐Garzón P. , Harrington R. M. , Bohnhoff M. 
Published: December 2020

AbstractTectonic tremor has been observed at the roots of many fault systems around the Pacific rim, including convergent and transform plate boundaries. The extent to which deep tremor signals are prevalent along fault systems elsewhere, including the Mediterranean basin, has not yet been documented in detail. A body of evidence suggests that tremor triggered during the surface waves of teleseismic events may commonly occur where ambient tremor during episodic tremor and slip episodes occur, suggesting triggered tremor provides a useful tool to identify regions with ambient tremor. We perform a systematic search of triggered tremor associated with large teleseismic events between 2010 and 2020 at four major fault systems within the central‐eastern Mediterranean basin, namely the Hellenic and Calabrian subduction zones, and the North Anatolian and Kefalonia transform faults. In addition, we search for ambient tremor during a slow slip event in the eastern Sea of Marmara along a secondary branch of the North Anatolian Fault, and two slow slip events beneath western Peloponnese (Hellenic Subduction Zone). We find no unambiguous evidence for deep triggered tremor, nor ambient tremor. The absence of triggered tremor at the Hellenic and Calabrian subduction zones supports an interpretation of less favorable conditions for tremorgenesis in the presence of old and cold slabs. The absence of tremor along the transform faults may be due to an absence of the conditions commonly promoting tremorgenesis in such settings, including high‐fluid pressures and low‐differential stresses between the down‐dip limit of the seismogenic layer and the continental Moho.
Improved Measurements of Short‐Period Mass Variations With Future Earth Gravity Missions
Authors: Kang K. , Bender P. L. 
Published: December 2020

AbstractA new mission called the Gravity Recovery And Climate change Experiment Follow‐On (GRACE‐FO) is now flying to continue the measurements started by the GRACE mission and to test a laser interferometry system for making more accurate measurements of the satellite separation. In this study, we discuss the potential scientific benefit of strongly reducing the acceleration noise in a Next Generation Gravity Mission (NGGM), compared with that for GRACE and for GRACE‐FO. A useful way of comparing the scientific benefits is from the view point of how well they can be used to test different procedures for estimating the changes in the geopotential based on sources of geophysical information other than satellite gravity results. In particular, changes in hydrology, the atmospheric density, and ocean conditions can make large and very nonuniform changes in the geopotential in short periods of time. To make the discussion as simple as possible, we consider mainly the variations in the geopotential at altitude along the satellite orbit for different ground tracks. For the NGGM, we initially assume laser interferometry between the two satellites but the same satellite acceleration noise level as for the GRACE‐FO mission. Then the total measurement noise level at long and medium wavelengths would be only moderately below the geopotential variation estimation uncertainty. However, if the acceleration noise level were sharply reduced by replacing the GRACE‐type accelerometers by simplified gravitational reference sensors, it appears that improved tests of our understanding of the causes of the geopotential variations could be obtained.
Integrated Analysis of Multisensor Datasets and Oil Drift Simulations—A Free‐Floating Oil Experiment in the Open Ocean
Authors: Brekke Camilla , Espeseth Martine M. , Dagestad Knut‐Frode , Röhrs Johannes , Hole Lars Robert , Reigber Andreas 
Published: December 2020

AbstractA free‐floating oil spill experiment (two oil types) in the open ocean is described, and the results from slick characterization through integrated analysis of drift simulations with remote sensing and in situ data are discussed. We compare oil drift simulations (OpenOil), applying various configurations of wind, wave, and current information, with the observed slick positions and shape. We describe trajectories and dynamics of the spills, slick extent, and their evolution, and the differences in detection capabilities in optical instruments versus multifrequency PolSAR acquired by Deutsches Zentrum für Luft‐und Raumfahrt F‐SAR. When using the best available forcing from in situ data and forecast models, good agreement with the observed position and extent was found. A fair agreement is obtained using only numerical forecast data as input. This case study reveals that the accuracy when using modeled current is relatively higher after one full local inertial period, as the effect of incorrectly modeled amplitude of the inertial current is then vanishing. This should be a general result applicable to any oceanic drift forecast based on the modeled current. A novelty is the comparison of viscous‐similar soybean and mineral oil. Our findings indicate that biological oil emulsions potentially could replace mineral oil emulsions in contingency and rehearsal campaigns, but this finding is only supported from an oil drift prediction perspective. Differences in mineral oil detection capabilities are found between synthetic aperture radar and optical imagery of thinner sheen regions. F‐SAR appears to be more sensitive to thinner oil and detect a larger extent, and differences between the thinner and thicker parts are observed.
Multi‐Annual Monitoring of the Water Vapor Vertical Distribution on Mars by SPICAM on Mars Express
Authors: Fedorova Anna , Montmessin Franck , Korablev Oleg , Lefèvre Franck , Trokhimovskiy Alexander , Bertaux Jean‐Loup 
Published: December 2020

AbstractThe distribution of water vapor with altitude has long remained a missing piece of the observational data set of water vapor on Mars. In this study, we present the first multi‐annual survey of water vapor profile covering the altitude range from 0 to 100 km based on the SPICAM/Mars Express occultation measurements. During the aphelion season, water remains confined below 40–60 km for all Martian years observed. The highest altitude where water vapor can be spotted is between 70 and 90 km during the southern summer (Ls = 240–300°; perihelion season), approaching the transition between the middle and upper atmosphere. In this season, years without a global dust storm (GDS) show a significant moistening of the upper atmosphere (∼100 ppmv) in the southern hemisphere, confirming a seasonal impact on the hydrogen escape rate. The two observed GDS, in MY28 and MY34, show a substantial disparity in water vapor response. The storm in MY28, which coincides with the southern summer solstice, creates the largest excess of water in both hemispheres at >80 km. This climatology of water vapor will supply a robust statistical basis to address the long‐term escape processes of water from Mars.
Adaptations of Coccolithophore Size to Selective Pressures During the Oligocene to Early Miocene High CO2 World
Authors: Guitián José , Dunkley Jones Tom , Hernández‐Almeida Ivan , Löffel Tim , Stoll Heather M. 
Published: December 2020

AbstractCulture experiments with coccolithophore algae—the dominant group of marine calcifying phytoplankton—imply a strong sensitivity in growth rate, degree of cellular calcification, and cell size to changes in the carbon chemistry of their growth environment. These results underpin recent studies that have explored how these physiological parameters have varied on geological time scales, in response to changing surface ocean habitats and the concentrations of carbon in the ocean‐atmosphere system. Here, we add to this work with a study of reticulofenestrid coccolith size—the dominant coccolithophore family of the Cenozoic—over the Oligocene to Early Miocene time interval. We examine sediments from contrasting latitudes and regional environmental settings, comparing sites using coherent, updated age models to distinguish globally synchronous trends in cell size from regional trends. Our results confirm several changes in coccolith size—which is strongly correlated to cell size—that are globally reproducible within the ~1 Myr age uncertainty, including a reduction in mean size by >2 μm from 30.2 to 27 and 24.5 to 23 Ma, and then increase in mean size after 20 Ma. The main difference among regions is the presence/absence of coccoliths larger than 8 μm. We evaluate which scenarios of change in carbon dioxide, temperature, and nutrient availability could have exerted selective pressure on cell size for different size classes to produce the observed size trends at each studied site. These million‐year scale adaptations of ancient coccolithophores contribute to the understanding of phytoplankton physiology in the transition to the modern “icehouse” world.