bluuebunny/crossref_metadata_2025 huggingface dataset:
Dementia care-giving and employment: a mixed-studies review on a presumed conflict
Authors: Neubert Lydia , König Hans-Helmut , Mietzner Claudia , Brettschneider Christian
Published: October 2019

Many persons with dementia live at home and are cared for by their relatives. If the relatives are still employed, this can lead to higher burden and losses in their work-life. The interplay between informal care-giving and working is complex. Different studies have explored this issue, but the results have not been yet synthesised. In this mixed-studies review, we elucidate the underlying complexity. Our objective is to identify the factors related to care-giving that influence employment, and to describe their impact on dementia care-givers’ employment. We performed a literature search of primary studies using four databases and one meta-database, and retrieved English- and German-language articles. We used the Mixed Methods Appraisal Tool to assess their methodological quality. Evidence identified was synthesised by a parallel-results convergent synthesis design. We included 55 qualitative, quantitative and mixed-method studies published up to January 2018. The emerging model identified factors linked to the care recipient with dementia, the informal care-giver and the care-giving context. The impacts of these factors on care-givers’ employment are mostly negative (e.g. stopped/reduced work, decreased job performance). Nevertheless, the results provide encouraging insights as working can counterbalance care-giving strain, and managing both roles can enhance care-givers’ wellbeing. Practical efforts should focus on enabling informal care-givers to better manage the balance between care-giving and work responsibilities.
Disulphide-less crotamine is effective for formation of DNA–peptide complex but is unable to improve bovine embryo transfection
Authors: Freitas Vicente J.F. , Campelo Iana S. , Silva Mirelly M.A.S. , Cavalcanti Camila M. , Teixeira Dárcio I.A. , Camargo Luiz S.A. , Melo Luciana M. , Rádis-Baptista Gandhi
Published: October 2019

This study aimed to investigate the ability of disulphide-less crotamine (dLCr) to complex DNA and to evaluate whether the DNA–dLCr complex is capable of improving transfection in bovine embryos. Three experiments were performed to: (i) evaluate the formation and stability of the DNA–dLCr complex; (ii) assess the dLCr embryotoxicity by exposure of bovine embryos to dLCr; and (iii) assess the efficiency of bovine embryo transfection after microinjection of the DNA–dLCr complex or green fluorescent protein (GFP) plasmid alone (control). DNA complexation by dLCr after 30 min of incubation at 1:100 and 1:50 proportions presented higher efficiency (P < 0.05) than the two controls: native crotamine (NCr) 1:10 and lipofectamine. There was no difference between DNA–dLCr 1:25 and the controls. The DNA–dLCr complexation was evaluated at different proportions and times. In all, at least half of maximum complexation was achieved within the initial 30 min. No embryotoxicity of dLCr was verified after exposure of in vitro fertilized embryos to different concentrations of the peptide. The effectiveness of dLCr to improve exogenous gene expression was evaluated by microinjection of the DNA–dLCr complex into in vitro fertilized zygotes, followed by verification of both embryo development and GFP expression. From embryos microinjected with DNA only, 4.6% and 2.8% expressed the GFP transgene at day 5 and day 7, respectively. The DNA–dLCr complex did not increase the number of GFP-positive embryos. In conclusion, dLCr forms a complex with DNA and its application in in vitro culture is possible. However, the dLCr peptide sequence should be redesigned to improve GFP expression.
THE QUANDARY OF QUANDLES: A BOREL COMPLETE KNOT INVARIANT
Authors: BROOKE-TAYLOR ANDREW D. , MILLER SHEILA K.
Published: October 2019

We show that the isomorphism problems for left distributive algebras, racks, quandles and kei are as complex as possible in the sense of Borel reducibility. These algebraic structures are important for their connections with the theory of knots, links and braids. In particular, Joyce showed that a quandle can be associated with any knot, and this serves as a complete invariant for tame knots. However, such a classification of tame knots heuristically seemed to be unsatisfactory, due to the apparent difficulty of the quandle isomorphism problem. Our result confirms this view, showing that, from a set-theoretic perspective, classifying tame knots by quandles replaces one problem with (a special case of) a much harder problem.
Full-spectral fitting techniques to characterise the stellar content of ultra diffuse galaxies
Authors: Ruiz-Lara Tomás , Beasley M. A. , Gallart C. , Falcón-Barroso J. , Battaglia G. , Bernard E. , Brook C. , Di Cintio A. , Florido E. , Martín-Navarro I. , Monelli M. , Pérez I. , Pinna F. , Román J. , Sánchez-Blázquez P. , Trujillo I. , Vazdekis A.
Published: October 2019

Understanding the peculiar properties of Ultra Diffuse Galaxies (UDGs) via spectroscopic analysis is a challenging task that is now becoming feasible. The advent of 10m-class telescopes and high sensitivity instruments is enabling the gathering of high quality spectra even for the faintest systems. In addition, advances in the modelling of stellar populations, stellar libraries, and full-spectral fitting codes are allowing the recovery of the stellar content shaping those spectra with unprecedented reliability. In this contribution we report on the extensive tests we have carried out using the inversion code STECKMAP. The similarities between the Star Formation Histories (SFH) recovered from STECKMAP (applied to high-quality spectra) and deep Colour-Magnitude diagrams fitting (resolved stars) in two Local Group dwarf galaxies (LMC and LeoA) are remarkable, demonstrating the impressive performance of STECKMAP. We exploit the capabilities of STECKMAP and perform one of the most complete and reliable characterisations of the stellar component of UDGs to date using deep spectroscopic data. We measure radial and rotation velocities, SFHs and mean population parameters, such as ages and metallicities, for a sample of five UDG candidates in the Coma cluster. From the radial velocities, we confirm the Coma membership of these galaxies. We find that their rotation properties, if detected at all, are compatible with dwarf-like galaxies. The SFHs of the UDG are dominated by old (∼ 7 Gyr), metal-poor ([M/H] ∼ -1.1) and alpha-enhanced ([Mg/Fe]∼ 0.4) populations followed by a smooth or episodic decline which halted ∼ 2 Gyr ago, possibly a sign of cluster-induced quenching. We find no obvious correlation between individual SFH shapes and any UDG morphological properties. The recovered stellar properties for UDGs are similar to those found for DDO 44, a local UDG analogue resolved into stars. We conclude that the UDGs in our sample are extended dwarfs whose properties are likely the outcome of both internal processes, such as bursty SFHs and/or high-spin haloes, as well as environmental effects within the Coma cluster.
Molecular Composition of Local Dwarf Galaxies: Astrochemistry in Low-metallicity Environments
Authors: Nishimura Yuri , Shimonishi Takashi , Watanabe Yoshimasa , Sakai Nami , Aikawa Yuri , Kawamura Akiko , Kohno Kotaro , Yamamoto Satoshi
Published: October 2019

To investigate molecular composition of low-metallicity environments, we conducted spectral line survey observations in the 3 mm band toward three dwarf galaxies, the Large Magellanic Cloud, IC 10, and NGC 6822 with the Mopra 22 m, the Nobeyama 45 m and the IRAM 30 m, respectively. The rotational transitions of CCH, HCN, HCO+, HNC, CS, SO, 13CO, and 12CO were detected in all three galaxies. We found that the spectral intensity patterns are similar to one another regardless of star formation activities. Compared with Solar-metallicity environments, the molecular compositions of dwarf galaxies are characterized by (1) deficient nitrogen-bearing molecules and (2) enhanced CCH and suppressed CH3OH. These are interpreted (1) as a direct consequence of the lower elemental abundance of nitrogen, and (2) as a consequence of extended photon dominated regions in cloud peripheries due to the lower abundance of dust grains, respectively.
The Future of Dwarf Galaxy Research: What Telescopes Will Discover
Authors: Haynes Martha P.
Published: October 2019

Dwarf galaxies make ideal laboratories to test galaxy evolution paradigms and cosmological models. Detailed studies of dwarfs across the spectrum allow us to gauge the efficacy of astrophysical processes at play in the lowest mass halos such as gas accretion, feedback, turbulence and chemical enrichment. Future observational studies will deliver unprecedented insights on the orbits of dwarf companions around the Milky Way, on their star formation histories and on the 3-D internal motions of their stars. Over large volumes, we will assess the impact of local environment on baryon cycling and star formation laws, leading to a full picture of the evolution of dwarfs across cosmic time. In combination, future discoveries promise to trace the history of assembly within the Local Group and beyond, probe how stars form under pristine conditions, and test models of structure formation on small scales.
Origin and Transformation of Light Hydrocarbons Ascending at an Active Pockmark on Vestnesa Ridge, Arctic Ocean
Authors: Pape T. , Bünz S. , Hong W.‐L. , Torres M. E. , Riedel M. , Panieri G. , Lepland A. , Hsu C.‐W. , Wintersteller P. , Wallmann K. , Schmidt C. , Yao H. , Bohrmann G.
Published: October 2019

We report on the geochemistry of hydrocarbons and pore waters down to 62.5 mbsf, collected by drilling with the MARUM‐MeBo70 and by gravity coring at the Lunde pockmark in the Vestnesa Ridge. Our data document the origin and transformations of volatiles feeding gas emissions previously documented in this region. Gas hydrates are present where a fracture network beneath the pockmark focusses migration of thermogenic hydrocarbons characterized by their C1/C2+ and stable isotopic compositions (δ2H‐CH4, δ13C‐CH4). Measured geothermal gradients (~80 °C/km) and known formation temperatures (>70 °C) suggest that those hydrocarbons are formed at depths >800 mbsf. A combined analytical/modeling approach, including concentration and isotopic mass balances, reveals that pockmark sediments experience diffuse migration of thermogenic hydrocarbons. However, at sites without channeled flow this appears to be limited to depths >~50 mbsf. At all sites we document a contribution of microbial methanogenesis to the overall carbon cycle that includes a component of secondary carbonate reduction—that is, reduction of dissolved inorganic carbon generated by anaerobic oxidation of methane in the uppermost methanogenic zone. Anaerobic oxidation of methane and carbonate reduction rates are spatially variable within the pockmark and are highest at high‐flux sites. These reactions are revealed by 13C depletions of dissolved inorganic carbon at the sulfate‐methane interface at all sites. However, 13C depletions of CH4 are only observed at the low methane flux sites because changes in the isotopic composition of the overall methane pool are masked at high‐flux sites. 13C depletions of total organic carbon suggest that at seeps sites, methane‐derived carbon is incorporated into de novo synthesized biomass.
Relating Precipitating Ice Radiative Effects to Surface Energy Balance and Temperature Biases Over the Tibetan Plateau in Winter
Authors: Lee Wei‐Liang , Li Jui‐Lin Frank , Xu Kuan‐Man , Suhas Ettamal , Jiang Jonathan H. , Wang Yi‐Hui , Stephens Graeme , Fetzer Eric , Yu Jia‐Yuh
Published: October 2019

Key Points

Surface temperature bias is primarily determined by biases of surface radiative fluxes

Underestimated ice water path in models is related to radiation deficiency and cold bias over the Tibetan Plateau in winter

Precipitating ice radiative effects are responsible for some reduction of biases in surface radiative fluxes and temperature
Path Independence of Carbon Budgets When Meeting a Stringent Global Mean Temperature Target After an Overshoot
Authors: Tokarska Katarzyna B. , Zickfeld Kirsten , Rogelj Joeri
Published: October 2019

Emission pathways that are consistent with meeting the Paris Agreement goal of holding global mean temperature rise well below 2 °C often assume a temperature overshoot. In such overshoot scenarios, a given temperature limit is first exceeded and later returned to, under the assumption of large‐scale deliberate carbon dioxide removal from the atmosphere. Here we show that although such strategy might result in a reversal of global mean temperature, the carbon cycle exhibits path dependence. After an overshoot, more carbon is stored in the ocean and less on land compared to a scenario with the same cumulative CO2 emissions but no overshoot. The near‐path independence of surface air temperature arises despite the path dependence in the carbon cycle, as it is offset by path dependence in the thermal response of the ocean. Such behavior has important implications for carbon budgets (i.e. the total amount of CO2 emissions consistent with holding warming to a given level), which do not differ much among scenarios that entail different levels of overshoot. Therefore, the concept of a carbon budget remains robust for scenarios with low levels of overshoot (up to 300 Pg C overshoot considered here) but should be used with caution for higher levels of overshoot, particularly for limiting the environmental change in dimensions other than global mean temperature rise.
The Infrastructure Impacts of Solar Storms
Authors: Gannon Jennifer
Published: October 2019

A new book brings together insights from the space weather, geophysics, and power engineering communities to understand the characteristics and impacts of geomagnetically induced currents.
California Launches Nation’s First Earthquake Early Warning System
Authors: Duncombe Jenessa
Published: October 2019

The country’s first publicly available, statewide warning system could give California residents seconds to duck and cover before a quake.
Dead Whales, Dinosaurs, a Yeti, and Other Spooky News of the Week
Authors:   AGU
Published: October 2019

What Earth and space science stories are we recommending this week?
Interplay of Subduction Tectonics, Sedimentation, and Carbon Cycling
Authors: Riedinger N. , Torres M.E. , Screaton E. , Solomon E.A. , Kutterolf S. , Schindlbeck‐Belo J. , Formolo M.J. , Lyons T.W. , Vannucchi P.
Published: October 2019

Distinct differences were observed in geochemical signatures in sediments from two sites drilled in the upper plate of the Costa Rica margin during Integrated Ocean Drilling Program (IODP) Expedition 334. The upper 80 m at Site U1379, located on the outer shelf, shows pore water non‐steady state conditions characteristic of a declining methane flux. These contrast with analyses of the upper sediment layers at the middle slope site (U1378) that reflect steady state conditions. Distinct carbonate‐rich horizons up to 11 meters thick were recovered between 63 and 310 meters below seafloor at Site U1379 but were not found at Site U1378. The carbonates and dissolved inorganic carbon from Site U1379 have a depleted carbon stable isotope signal (up to −25‰) that indicates anaerobic methane oxidation. This inference is further supported by distinct δ34S‐pyrite and magnetic susceptibility records that reveal fluctuations of the sulfate‐methane transition in response to methane flux variations. Tectonic reconstructions of this margin document a marked subsidence event after arrival of the Cocos Ridge, 2.2 ± 0.2 million years ago (Ma), followed by increased sedimentation rates and uplift. As the seafloor at Site U1379 rose from ~2,000 m to the present water depth of ~126 m, the site moved out of the gas hydrate stability zone at ~1.1 Ma, triggering upward methane advection, methane oxidation, and the onset of massive carbonate formation. Younger carbonate occurrences and the non‐steady state pore water profiles at Site U1379 reflect continued episodic venting likely modulated by changes in the underlying methane reservoir.
Post Mid‐Cretaceous Tectonic and Topographic Evolution of Western Marie Byrd Land, WestAntarctica: Insights from Apatite FissionTrack and (U‐Th‐Sm)/He Data
Authors: Zundel Maximilian , Spiegel Cornelia , Lisker Frank , Monien Patrick
Published: October 2019

New low‐temperature thermochronological data from granitic basement of western Marie Byrd Land (MBL) provide insights into the still poorly constrained tectonic and topographic evolution of West Antarctica during and after continental breakup. Here, we present the first apatite (U‐Th‐Sm)/He data from the Devonian Ford Granodiorite and the mid‐Cretaceous Byrd Coast Granite suites from the Ford Ranges and the Edward VII Peninsula. Thermal history modeling integrating apatite (U‐Th‐Sm)/He dates of 109–68 Ma with revised apatite fission track data in combination with geologic information indicates a thermal history with diachronous enhanced cooling at ~100–60 Ma and subsequent slow cooling until the present day. Enhanced cooling at ~100–70 Ma was related to activity of the West Antarctic rift system and to continental breakup, thereby exhuming most samples to shallow crustal levels. Localized cooling at ~75–60 Ma is interpreted as resulting from faulting in the eastern Ross Sea region. Slow cooling after ~70–60 Ma corresponds with formation of erosion surfaces in western MBL. Comparison of our results from western MBL with data from the literature indicates progressive formation of erosion surfaces from west to east along the MBL‐Thurston Island crustal blocks. Late Cenozoic activity of the West Antarctic rift system and MBL dome uplift appear to have caused only minor exhumation of <1.5 km in western MBL.
The Cold Ion Population at Geosynchronous Orbit and Transport to the Dayside Magnetopause: September 2015 to February 2016
Authors: Denton M. H. , Henderson M. G. , Maruyama N. , Fuselier S. A.
Published: October 2019

During intervals of enhanced magnetospheric convection, a high‐density plume of cold ions is eroded from the plasmasphere and can flow toward the dayside magnetopause where it has the potential to reduce the rate of magnetic reconnection. In any interval of long‐duration enhanced convection, tons of ions may follow such a trajectory. The study here concerns cold ion observations from geosynchronous orbit (GEO) during both calm and active periods. Probability distributions of the cold ion density and cold ion flow speed are determined during the 6‐month period from September 2015 to February 2016, inclusive. During low geomagnetic activity, the cold, dense ions are in corotation with the Earth, and flow speeds rarely exceed 10 km/s. During elevated geomagnetic activity, the cold ions between 12 and 18 magnetic local time are observed to flow toward the dayside magnetosphere with a speed of >10 km/s approximately 50% of the time. The Shue et al. (1998, https://doi.org/10.1029/98JA01103) model of the magnetopause location is used to derive the distribution of approximate minimum times for the cold ions to be transported from GEO to the dayside magnetopause. On average, during enhanced convection periods (Kp > 3) ions will take a mean time of ~4.5 hr to travel from GEO to the dayside magnetopause.
Mapping Deep Electrical Conductivity Structure in the Mount Isa region, Northern Australia: Implications for Mineral Prospectivity
Authors: Jiang Wenping , Korsch Russell J. , Doublier Michael P. , Duan Jingming , Costelloe Ross
Published: October 2019

The Mount Isa Province in northern Australia is one of the world's most strongly endowed regions for base metals and host to major iron–oxide–copper–gold (IOCG) deposits. The Carpentaria conductivity anomaly at the eastern margin of the province is a major electrical conductivity structure of the Australian continent. We use magnetotelluric data to image the crustal architecture in this highly mineralized region. The resistivity models reveal a number of prominent crustal‐scale conductors, suggesting that the Carpentaria conductivity anomaly is likely caused by a series of isolated or interconnected bodies. These conductors confirm the position and geometry of the ancient Gidyea Suture zone, the eastern boundary of the Mount Isa Province, interpreted as a west‐dipping subduction zone. The Carpentaria conductivity anomaly may record the activity of fluid dehydration involved during a subduction event, with the enhanced conductivity likely being caused by deformation or mineralization of graphitic or sulfidic rocks during orogenesis. The major iron oxide in the Ernest Henry IOCG deposit located in the hanging wall of the Gidyea Suture zone is magnetite, suggesting another possible conductive source. The distribution of known gold and copper deposits shows a close spatial correlation with the suture zone, suggesting that this structure is potentially a fundamental control on IOCG deposits in its vicinity. The implication is that crustal‐penetrating structures act as potential pathways for fluid movement to form mineral deposits in the upper crust. The significance of mapping such structures using geophysics is highlighted for mineral exploration.
Hf and Nd Isotopic Constraints on Pre‐ and Syn‐collisional Crustal Thickness of Southern Tibet
Authors: Alexander E. W. , Wielicki M. M. , Harrison T. M. , DePaolo D. J. , Zhao Z. D. , Zhu D. C.
Published: October 2019

In Southern Tibet, voluminous granitoids emplaced between 225‐20 Ma provide a spatiotemporal window into the geochemical and tectonic evolution of the crust. Hf and O isotope geochemistry of whole rocks and constituent zircons together with whole‐rock chemistry reveal a coherent magmatic history of Gangdese granitoids, and by extension, crustal thickening history of S. Tibet. We observe a spatial isotopic gradient with N‐S distance from the Indus‐Tsangpo Suture (ITS), with younger, more εHf‐positive granitoids adjacent the ITS. Zircons range from εHf = ‐13 to +11 in a broadly systematic fashion from north to south, generally independent of 206Pb/238U age. Adjacent to the ITS, syncollisional (<50 Ma) rocks have generally more heterogeneous εHf than precollisional (>70 Ma) and early syncollisional (50‐70 Ma) granitoids, likely reflecting increased assimilation of crustal material in syncollisional magmas as the crust thickened. Zircon δ18O ranges between +4 and +8‰; syncollisional samples have exclusively mantle‐like values (+5.5 to +6‰), with greater heterogeneity in precollisional samples. Zircon and whole‐rock εHf data reported here are consistent with previous Nd‐based thermoisotopic models indicating that the Lhasa block maintained a wedge‐shaped crustal geometry from the early Jurassic until the onset of collision. Given evidence of minimal post‐50 Ma upper‐crustal shortening, these results support earlier findings that the Tibetan crust reached its present ~75 km thickness via a roughly equal mixture of upper plate accretion and juvenile magmatic inflation on top of the ~30 km‐thick of Indian crust underthrust beneath the Lhasa block.
Seismic Structure of the Antarctic Upper Mantle Imaged with Adjoint Tomography
Authors: Lloyd A. J. , Wiens D. A. , Zhu H. , Tromp J. , Nyblade A. A. , Aster R. C. , Hansen S. E. , Dalziel I. W. D. , Wilson T.J. , Ivins E. R. , O’Donnell J. P.
Published: October 2019

The upper mantle and transition zone beneath Antarctica and the surrounding oceans are among the poorest‐imaged regions of the Earth's interior. Over the last 15 years, several large broadband regional seismic arrays have been deployed, as have new permanent seismic stations. Using data from 297 Antarctic and 26 additional seismic stations south of ~40°S, we image the seismic structure of the upper mantle and transition zone using adjoint tomography. Over the course of 20 iterations, we utilize phase observations from three‐component seismograms containing P, S, Rayleigh, and Love waves, including reflections and overtones, generated by 270 earthquakes that occurred from 2001–2003 and 2007–2016. The new continental‐scale seismic model (ANT‐20) possesses regional‐scale resolution south of 60°S. In East Antarctica, thinner continental lithosphere is found beneath areas of Dronning Maud Land and Enderby‐Kemp Land. A continuous slow wave speed anomaly extends from the Balleny Islands through the western Ross Embayment and delineates areas of Cenozoic extension and volcanism that span both oceanic and continental regions. Slow wave speed anomalies are also imaged beneath Marie Byrd Land and along the Amundsen Sea Coast, extending to the Antarctic Peninsula. These anomalies are confined to the upper 200–250 km of the mantle, except in the vicinity of Marie Byrd Land where they extend into the transition zone and possibly deeper. Finally, slow wave speeds along the Amundsen Sea Coast link to deeper anomalies offshore, suggesting a possible connection with deeper mantle processes.
Confirmation of a Late Miocene Subchron C4n.2n‐1r From the Eastern Qaidam Basin in the NE Tibetan Plateau
Authors: Gao Peng , Nie Junsheng , Li Mingsong , Li Pu
Published: October 2019

Refining reversal ages and improving reversal patterns for the geomagnetic polarity timescale are a major task for the paleomagnetic community. The Late Miocene is a period during which the geomagnetic field experienced frequent perturbations and which dramatic environmental changes occurred. Thus, improved (sub)chron definition during this period will enable to provide additional age control points for better understanding age of paleoenvironmental changes. A prior study of the Late Miocene C4n.2n magnetic polarity zone at Ocean Drilling Program Site 1092 in the sub‐Antarctic South Atlantic Ocean has revealed the potential existence of a subchron (C4n.2n‐1r). However, this subchron has not been incorporated into the geomagnetic polarity timescale yet because its existence has not been confirmed. Moreover, the low sediment accumulation rate of 1.32 cm/kyr at Site 1092 hampers a confident estimation of the age and duration of this subchron. Here we present a high‐resolution paleomagnetic data set covering C4n.2n from the Huaitoutala section in the eastern Qaidam Basin, Northwest China, with an average sediment accumulation rate of ~22 cm/kyr. Nine reversed declination/inclination data points define a subchron near the top of C4n.2n, similar to age of reported C4n.2n‐1r at Ocean Drilling Program Site 1092. Cyclostratigraphy of the magnetic susceptibility record of the Huaitoutala section suggests that the age and duration of the C4n.2n‐1r are 7.7612–7.7554 Ma and 5.8 ± 2.1 kyr, respectively. Confirming the existence of C4n.2n‐1r from a northern hemisphere terrestrial site suggests that two geomagnetic reversals bounding this subchron have global imprints and that this subchron can potentially serve as marker for stratigraphic correlation.
Fault Reactivation During Fluid Pressure Oscillations: Transition From Stable to Unstable Slip
Authors: Noël Corentin , Passelègue François X. , Giorgetti Carolina , Violay Marie
Published: October 2019

High‐pressure fluid injection in deep georeservoirs can induce earthquakes. Recent observations suggest that cyclic injections might trigger less seismicity than monotonic injections. Here, we report triaxial laboratory experiments conducted on faulted quartz‐rich sandstone that provide new insight into the physics of fault‐fluid interactions subjected to cyclic fluid pressure variations. The experiments were performed at 30 and 45 MPa confining pressure, imposing constant or sinusoidal fluid pressure oscillations of amplitudes ranging from 0 to 8 MPa in addition to a far‐field constant loading rate (10−4 and 10−3 mm s−1). The results show that (i) in agreement with the Mohr‐Coulomb theory, faults reactivate at the static friction criterion, which is generally reached at the maximum fluid pressure during oscillations. (ii) Oscillating fluid pressure perturbations promote seismic behavior rather than aseismic slip, and (iii) increasing the oscillation's amplitude enhances the onset of seismic activity along the fault. We demonstrate that this behavior is caused by slip rate variations resulting from the fluid pressure oscillations. Without fluid pressure oscillations, increasing the far‐field loading rate also promotes seismic activity. Our experiments demonstrate that the seismicity intensification due to cyclic fluid injections could be promoted at shallow depth, where confining pressure is relatively low, resulting in large strain rate perturbations.
The Variability of Winds and Fluxes Observed Near Submesoscale Fronts
Authors: Shao Mingming , Ortiz‐Suslow David G. , Haus Brian K. , Lund Björn , Williams Neil J. , Özgökmen Tamay M. , Laxague Nathan J. M. , Horstmann Jochen , Klymak Jody M.
Published: October 2019

Submesoscale oceanic fronts (SFs), which typically occur on a spatial scale of 0.1–10 km, may have a large influence on the atmospheric surface layer (ASL). However, due to their short temporal‐spatial scales, evaluating their direct impact on this layer remains challenging and characterizing the nature of SF‐ASL interaction has not been done in the field. To address this, a study of the air‐sea response to SFs was conducted using observations collected during the Lagrangian Submesoscale Experiment, which took place in the northern Gulf of Mexico. This manuscript focuses on the meteorological measurements made from a pair of masts installed on the bow of the R/V Walton Smith. This work represents one of the first observation‐based investigations into the potential influence that SFs have on the ASL. Contemporaneous measurements from an X‐band marine radar, moving vessel profiler, and Lagrangian drifters were also used to analyze the SF dynamics. Systematic surface wind velocity changes over several cross‐frontal transects were observed, a process previously associated with mesoscale fronts. A comparison between the eddy covariance and parameterized (COARE 3.5) air‐sea fluxes revealed that the directly observed heat flux was 1.5 times larger than the bulk value in the vicinity of the SFs. This suggests that the hydrodynamic processes near the front enhance the local exchange of sensible and latent heat. Given the prevalence of SF over the global upper ocean, these findings suggest that these features may have a widely distributed and cumulative impact on air‐sea interactions.
Suppressed CO2 Outgassing by an Enhanced Biological Pump in the Eastern Tropical Pacific
Authors: Kim Hyung Jeek , Kim Tae‐Wook , Hyeong Kiseong , Yeh Sang‐Wook , Park Jong‐Yeon , Yoo Chan Min , Hwang Jeomshik
Published: October 2019

The Eastern Tropical Pacific (ETP) is the largest oceanic source of carbon dioxide (CO2) to the atmosphere. Sinking particle fluxes at a depth of 4,950 m (50 m above the seafloor) in the ETP were monitored from 2003 to 2013, during which the Pacific decadal oscillation (PDO) shifted from a positive to negative phase. We show a disproportionate increase in the efficiency of the biological pump in this region relative to the increase in primary production that occurred during La Niña years following the shift of the PDO in 2008. Biogenic carbon export from the surface mixed layer was estimated from the observed particulate organic carbon and inorganic carbon fluxes at a depth of 4,950 m and from empirical equations of the vertical attenuation of carbon flux. Enhanced biological carbon export accounted for 2.3–5.5 mol C m–2 year–1 during the La Niña events. Despite a large uncertainty associated with these estimates, we propose that CO2 outgassing was largely suppressed by an enhanced biological pump during the La Niña events in the negative PDO phase.
Flood Inundation Generation Mechanisms and Their Changes in 1953–2004 in Global Major River Basins
Authors: Mao Yuna , Zhou Tian , Leung L. Ruby , Tesfa Teklu K. , Li Hong‐Yi , Wang Kaicun , Tan Zeli , Getirana Augusto
Published: October 2019

Despite the serious threats posed by floods, the driving mechanisms of floods are still not well understood. Here we apply a physically based inundation model coupled with a river routing model (Model for Scale Adaptive River Transport (MOSART)) within the Energy Exascale Earth System Model (E3SM) framework to investigate flood inundation dynamics. After calibration using observed streamflow and satellite‐derived flood extent, the model is used to simulate global flood inundation from 1953 to 2004. The mean date and seasonality of annual maximum flood, defined based on flood extent, exhibit significant regional differences across 16 major basins. Generally, soil moisture and monthly maximum daily rainfall (MMR) are the dominant drivers of flood in tropical basins while monthly maximum daily snowmelt (MMS) is the dominant driver in high‐latitude basins. From 1953–1982 to 1975–2004, significant changes in flood generation mechanisms are found in some basins such as Amazon, Lena, Yenisey, and Kolyma. Analysis of the rainfall seasonality and water balance at grid scale reveals a stronger rainfall seasonality in the Amazon during the later period that increases the synchrony between extreme rainfall and wet soil. With high antecedent soil moisture coinciding with rainfall, MMR contributes more to flood in the later period. Fewer extreme rainfall events and increasing soil moisture reduced the contribution of MMR and increased the role of MMS in floods in the Lena and Yenisey basins, respectively. Lastly, increased soil moisture and frequency of large MMS reduced the contribution of the latter to floods in the Kolyma basin.
From Toppling to Sliding: Progressive Evolution of the Moosfluh Landslide, Switzerland
Authors: Glueer Franziska , Loew Simon , Manconi Andrea , Aaron Jordan
Published: October 2019

This paper presents a detailed analysis of a dramatic rock slope acceleration that occurred in fall 2016 at the Moosfluh Landslide, located at the glacier tongue of the Great Aletsch Glacier (Switzerland). The acceleration that occurred in 2016 was unanticipated and exposed the valley bottom and an adjacent damned lake to high risk. This acceleration occurred in an active deep‐seated gravitational slope deformation (DSGSD) controlled primarily by deep block‐flexural toppling. In 2013, a highly accurate displacement monitoring system was developed and installed in the surroundings of the Great Aletsch Glacier, including a time‐lapse camera, GNSS, and robotic total stations. This monitoring system provided unique data during the 2016 slope acceleration which are used in this study to assess failure mechanisms, landslide volumes, and subsurface displacement geometry. Based on a novel displacement vector analysis, we find that three retrogressive secondary rockslides developed during the first six weeks of the slope acceleration, with rupture surface depths of 30 to 40 m, and estimated volumes between 1 and 4 Mm3. These rockslides display complex deformation features, including head and lateral scarps, which developed during the slope acceleration. The kinematics of these secondary rockslides changed through time, from primarily toppling to combined toppling and sliding. Our results provide a uniquely detailed understanding of the spatial and temporal evolution of deformation features and movement kinematics that occur when several sectors of a slowly moving DSGSD transitions into rapid rockslides.
Galileo Ionospheric Correction Algorithm: An Optimization Study of NeQuick‐G
Authors: Aragon‐Angel A. , Zürn M. , Rovira‐Garcia A.
Published: October 2019

At present most low‐cost GNSS receivers operate one frequency in the L band. For them one of the largest error contributions is the delay of radio signals in the Ionosphere. NeQuick‐G is the official ionospheric correction algorithm (ICA), which has been adopted for Galileo, the European GNSS Programme. The NeQuick‐G implementation is complex when compared with other ICAs. It is also demanding in terms of computational resources. The Joint Research Centre completed a reference implementation of NeQuick‐G based on the official document “Ionospheric Correction Algorithm for Galileo Single Frequency Users” provided by the European Global Navigation Satellite Systems Agency. The rationale behind the JRC implementation of NeQuick‐G was the intent to write an independent source code from scratch, without using the pseudo‐codes from the reference document and solely relying on the physics descriptions. Using such implementation as baseline, this paper describes an optimization attempt of the official pseudo‐code from an algorithmic perspective. The objective was to reduce the computational load while not sacrificing the performance. The new proposed integration method is able to speed up calculations to 21% and 49% with respect the two official integration algorithms. The overall computational burden depends on the number of operations, which is eventually closely correlated to the number of calls of the ionospheric model. This underlines the quest to find an integration method reducing this number of calls. Moreover, based on the findings of this study, the authors strongly recommend revisiting the convergence control of the integration routines introduced in (European Commission, 2016, https://www.gsc‐europa.eu/sites/default/files/sites/all/files/Galileo_Ionospheric_Model.pdf).
Detrital Zircon Geochronology of Upper Cretaceous to Paleocene Sandstones From South‐Central Wyoming: Evidence for Middle Campanian Laramide Deformation
Authors: Lynds R. M. , Xie X.
Published: October 2019

Laramide deformation during the Late Cretaceous through early Eocene interrupted the east‐flowing drainage systems from the Sevier hinterland and segmented the Western Interior Foreland Basin in much of western North America into a series of intermontane basins and Precambrian basement‐cored uplifts. In Wyoming, the timing of Laramide deformation and its impacts on drainage patterns during the overlap in the Sevier and Laramide orogenies remain under debate. New detrital zircon U‐Pb geochronologic data from 11 outcrop samples (n = 3,085) in south‐central Wyoming suggest at least two provenance‐distribution phases, distinguished by a substantial increase in zircons of late Paleoproterozoic age (1800–1600 Ma) recorded at approximately 79 Ma. The most likely source of late Paleoproterozoic age zircons is Precambrian basement‐cored uplifts, specifically the Sierra Madre Mountains, signaling the possible middle Campanian initiation of Laramide uplift, earlier than previously recorded. When combined with complementary data sets from surrounding basins, the first provenance‐distribution phase is age discordant, with the earliest evidence of 1800–1600 Ma zircons in the Piceance Basin of Colorado (late Santonian to early Campanian). The second provenance phase shows repeating age distribution patterns that begin with significant contributions from 1800 to 1600 Ma zircon grains and end with much broader and evenly distributed population signatures, confirming previous interpretations of significant Laramide deformation during the Maastrichtian (approximately 70 Ma) as well as uplift and recycling of Upper Cretaceous formations at about 67 Ma.
The role of the retinoids in schizophrenia: genomic and clinical perspectives
Authors: Reay William R. , Cairns Murray J.
Published: October 2019

Signalling by retinoid compounds is vital for embryonic development, with particular importance for neurogenesis in the human brain. Retinoids, metabolites of vitamin A, exert influence over the expression of thousands of transcripts genome wide, and thus, act as master regulators of many important biological processes. A significant body of evidence in the literature now supports dysregulation of the retinoid system as being involved in the aetiology of schizophrenia. This includes mechanistic insights from large-scale genomic, transcriptomic and, proteomic studies, which implicate disruption of disparate aspects of retinoid biology such as transport, metabolism, and signalling. As a result, retinoids may present a valuable clinical opportunity in schizophrenia via novel pharmacotherapies and dietary intervention. Further work, however, is required to expand on the largely observational data collected thus far and confirm causality. This review will highlight the fundamentals of retinoid biology and examine the evidence for retinoid dysregulation in schizophrenia.
Discovery of dual-activity small-molecule ligands of Pseudomonas aeruginosa LpxA and LpxD using SPR and X-ray crystallography
Authors: Kroeck Kyle G. , Sacco Michael D. , Smith Emmanuel W. , Zhang Xiujun , Shoun Daniel , Akhtar Afroza , Darch Sophie E. , Cohen Frederick , Andrews Logan D. , Knox John E. , Chen Yu
Published: October 2019

The lipid A biosynthesis pathway is essential in Pseudomonas aeruginosa. LpxA and LpxD are the first and third enzymes in this pathway respectively, and are regarded as promising antibiotic targets. The unique structural similarities between these two enzymes make them suitable targets for dual-binding inhibitors, a characteristic that would decrease the likelihood of mutational resistance and increase cell-based activity. We report the discovery of multiple small molecule ligands that bind to P. aeruginosa LpxA and LpxD, including dual-binding ligands. Binding poses were determined for select compounds by X-ray crystallography. The new structures reveal a previously uncharacterized magnesium ion residing at the core of the LpxD trimer. In addition, ligand binding in the LpxD active site resulted in conformational changes in the distal C-terminal helix-bundle, which forms extensive contacts with acyl carrier protein (ACP) during catalysis. These ligand-dependent conformational changes suggest a potential allosteric influence of reaction intermediates on ACP binding, and vice versa. Taken together, the novel small molecule ligands and their crystal structures provide new chemical scaffolds for ligand discovery targeting lipid A biosynthesis, while revealing structural features of interest for future investigation of LpxD function.
Long-term performance of seagrass restoration projects in Florida, USA
Authors: Rezek Ryan J. , Furman Bradley T. , Jung Robin P. , Hall Margaret O. , Bell Susan S.
Published: October 2019

Seagrass restoration is a common tool for ecosystem service enhancement and compensatory mitigation for habitat loss. However, little is known about the long-term performance of these projects. We identified seagrass restoration projects by reviewing historic permitting documents, monitoring reports, and studies conducted in Florida, USA, most of which have not been cited previously in peer-reviewed literature. We then revisited 33 seagrass restorations ranging in age from 3 to 32 years to compare seagrass percent cover, species diversity, and community structure in restored and contemporary reference seagrass beds. We found that 88% of restoration projects continued to support seagrass and, overall, restored percent cover values were 37% lower than references. Community composition and seagrass percent cover differed from references in projects categorized as sediment modification and transplant restorations, whereas all vessel damage repair projects achieved reference condition. Seagrass diversity was similar between restored and reference beds, except for sediment modification projects, for which diversity was significantly lower than in reference beds. Results indicate that restored seagrass beds in Florida, once established, often exhibit long-term persistence. Our study highlights the benefit of identifying and surveying historic restorations to address knowledge gaps related to the performance and long-term fate of restored seagrass beds.
Aβ modulates actin cytoskeleton via SHIP2-mediated phosphoinositide metabolism
Authors: Lee Hae Nim , Sim Kyoung Mi , Kim Hyunbin , Ju Jeongmin , Pae Ae Nim , Park Jae-Bong , Ryu Hoon , Seong Jihye
Published: October 2019

Emerging evidences suggest that phospholipid metabolism is altered in Alzheimer’s disease (AD), but molecular mechanisms on how this affects neurodegeneration in AD is poorly understood. SHIP2 is a phosphoinositide-metabolizing enzyme, which dephosphorylates PI(3,4,5)P3 resulting to PI(3,4)P2, and it has been recently shown that Aβ directly increases the activity of SHIP2. Here we monitored, utilizing fluorescent SHIP2 biosensor, real-time increase of PI(3,4)P2-containing vesicles in HT22 cells treated with Aβ. Interestingly, PI(3,4)P2 is accumulated at late endosomes and lysosomal vesicles. We further discovered that ARAP3 can be attracted to PI(3,4)P2-positive mature endosomes via its PH domain and this facilitates the degradation of ARAP3. The reduced level of ARAP3 then causes RhoA hyperactivation and filamentous actin, which are critical for neurodegeneration in AD. These results provide a novel molecular link between Aβ and actin disruption through dysregulated phosphoinositide metabolism, and the SHIP2-PI(3,4)P2-ARAP3-RhoA signaling pathway can be considered as new therapeutic targets for synaptic dysfunctions in Alzheimer’s disease.
Actomyosin contractility scales with myoblast elongation and enhances differentiation through YAP nuclear export
Authors: Bruyère Céline , Versaevel Marie , Mohammed Danahe , Alaimo Laura , Luciano Marine , Vercruysse Eléonore , Gabriele Sylvain
Published: October 2019

Skeletal muscle fibers are formed by the fusion of mononucleated myoblasts into long linear myotubes, which differentiate and reorganize into multinucleated myofibers that assemble in bundles to form skeletal muscles. This fundamental process requires the elongation of myoblasts into a bipolar shape, although a complete understanding of the mechanisms governing skeletal muscle fusion is lacking. To address this question, we consider cell aspect ratio, actomyosin contractility and the Hippo pathway member YAP as potential regulators of the fusion of myoblasts into myotubes. Using fibronectin micropatterns of different geometries and traction force microscopy, we investigated how myoblast elongation affects actomyosin contractility. Our findings indicate that cell elongation enhances actomyosin contractility in myoblasts, which regulate their actin network to their spreading area. Interestingly, we found that the contractility of cell pairs increased after their fusion and raise on elongated morphologies. Furthermore, our findings indicate that myoblast elongation modulates nuclear orientation and triggers cytoplasmic localization of YAP, increasing evidence that YAP is a key regulator of mechanotransduction in myoblasts. Taken together, our findings support a mechanical model where actomyosin contractility scales with myoblast elongation and enhances the differentiation of myoblasts into myotubes through YAP nuclear export.
Common neural value representations of hedonic and utilitarian products in the ventral striatum: An fMRI study
Authors: Motoki Kosuke , Sugiura Motoaki , Kawashima Ryuta
Published: October 2019

Hedonic goods are goods that people buy to obtain emotional experiences, such as joy or excitement, while utilitarian goods are bought to meet functional or instrumental needs. Although research in neuroscience suggests that the values of hedonic and utilitarian goods are similarly represented, it remains largely unknown how these values are mapped during purchasing decisions or task-irrelevant judgments. It has been suggested that people rely more on hedonic (vs. utilitarian) factors when making task-irrelevant judgments, and that this is amplified by trait-reward seeking. Functional magnetic resonance imaging (fMRI) can directly measure the mental processes involved in explicit or task-irrelevant value judgments. Using fMRI, we found that the explicit value of hedonic and utilitarian goods was commonly processed in the ventral striatum. In contrast, no significant results were obtained in common neural processing of task-irrelevant hedonic and utilitarian value. Additionally, we did not find any evidence that trait-reward seeking modulates task-irrelevant hedonic (vs. utilitarian) value processing. Our findings show that the value of both hedonic and utilitarian goods is commonly represented in the ventral striatum, and indicate that the value construct underlying consumer purchases is unidimensional.