bluuebunny/crossref_metadata_2025_split huggingface dataset:
Micrometer‐scale magnetic imaging of geological samples using a quantum diamond microscope
Authors: Glenn D. R. , Fu R. R. , Kehayias P. , Le Sage D. , Lima E. A. , Weiss B. P. , Walsworth R. L. 
Published: July 2017

AbstractRemanent magnetization in geological samples may record the past intensity and direction of planetary magnetic fields. Traditionally, this magnetization is analyzed through measurements of the net magnetic moment of bulk millimeter to centimeter sized samples. However, geological samples are often mineralogically and texturally heterogeneous at submillimeter scales, with only a fraction of the ferromagnetic grains carrying the remanent magnetization of interest. Therefore, characterizing this magnetization in such cases requires a technique capable of imaging magnetic fields at fine spatial scales and with high sensitivity. To address this challenge, we developed a new instrument, based on nitrogen‐vacancy centers in diamond, which enables direct imaging of magnetic fields due to both remanent and induced magnetization, as well as optical imaging, of room‐temperature geological samples with spatial resolution approaching the optical diffraction limit. We describe the operating principles of this device, which we call the quantum diamond microscope (QDM), and report its optimized image‐area‐normalized magnetic field sensitivity (20 µT⋅µm/Hz1/2), spatial resolution (5 µm), and field of view (4 mm), as well as trade‐offs between these parameters. We also perform an absolute magnetic field calibration for the device in different modes of operation, including three‐axis (vector) and single‐axis (projective) magnetic field imaging. Finally, we use the QDM to obtain magnetic images of several terrestrial and meteoritic rock samples, demonstrating its ability to resolve spatially distinct populations of ferromagnetic carriers.
Driving magma to the surface: The 2011–2012 El Hierro Volcanic Eruption
Authors: López Carmen , Benito‐Saz Maria A. , Martí Joan , del‐Fresno Carmen , García‐Cañada Laura , Albert Helena , Lamolda Héctor 
Published: July 2017

AbstractWe reanalyzed the seismic and deformation data corresponding to the preeruptive unrest on El Hierro (Canary Islands) in 2011. We considered new information about the internal structure of the island. We updated the seismic catalog to estimate the full evolution of the released seismic energy and demonstrate the importance of nonlocated earthquakes. Using seismic data and GPS displacements, we characterized the shear‐tensile type of the predominant fracturing and modeled the strain and stress fields for different time periods. This enabled us to identify a prolonged first phase characterized by hydraulic tensile fracturing, which we interpret as being related to the emplacement of new magma below the volcanic edifice on El Hierro. This was followed by postinjection unidirectional migration, probably controlled by the stress field and the distribution of the structural discontinuities. We identified the effects of energetic magmatic pulses occurring a few days before the eruption that induced shear seismicity on preexisting faults within the volcano and raised the Coulomb stress over the whole crust. We suggest that these magmatic pulses reflect the crossing of the Moho discontinuity, as well as changes in the path geometry of the dyke migration toward the surface. The final phase involved magma ascent through a prefractured crust.
Physics‐based forecasting of induced seismicity at Groningen gas field, the Netherlands
Authors: Dempsey David , Suckale Jenny 
Published: July 2017

AbstractEarthquakes induced by natural gas extraction from the Groningen reservoir, the Netherlands, put local communities at risk. Responsible operation of a reservoir whose gas reserves are of strategic importance to the country requires understanding of the link between extraction and earthquakes. We synthesize observations and a model for Groningen seismicity to produce forecasts for felt seismicity (M > 2.5) in the period February 2017 to 2024. Our model accounts for poroelastic earthquake triggering and rupture on the 325 largest reservoir faults, using an ensemble approach to model unknown heterogeneity and replicate earthquake statistics. We calculate probability distributions for key model parameters using a Bayesian method that incorporates the earthquake observations with a nonhomogeneous Poisson process. Our analysis indicates that the Groningen reservoir was not critically stressed prior to the start of production. Epistemic uncertainty and aleatoric uncertainty are incorporated into forecasts for three different future extraction scenarios. The largest expected earthquake was similar for all scenarios, with a 5% likelihood of exceeding M 4.0.
Reduction of initial shock in decadal predictions using a new initialization strategy
Authors: He Yujun , Wang Bin , Liu Mimi , Liu Li , Yu Yongqiang , Liu Juanjuan , Li Ruizhe , Zhang Cheng , Xu Shiming , Huang Wenyu , Liu Qun , Wang Yong , Li Feifei 
Published: July 2017

AbstractA novel full‐field initialization strategy based on the dimension‐reduced projection four‐dimensional variational data assimilation (DRP‐4DVar) is proposed to alleviate the well‐known initial shock occurring in the early years of decadal predictions. It generates consistent initial conditions, which best fit the monthly mean oceanic analysis data along the coupled model trajectory in 1 month windows. Three indices to measure the initial shock intensity are also proposed. Results indicate that this method does reduce the initial shock in decadal predictions by Flexible Global Ocean‐Atmosphere‐Land System model, Grid‐point version 2 (FGOALS‐g2) compared with the three‐dimensional variational data assimilation‐based nudging full‐field initialization for the same model and is comparable to or even better than the different initialization strategies for other fifth phase of the Coupled Model Intercomparison Project (CMIP5) models. Better hindcasts of global mean surface air temperature anomalies can be obtained than in other FGOALS‐g2 experiments. Due to the good model response to external forcing and the reduction of initial shock, higher decadal prediction skill is achieved than in other CMIP5 models.
Rapid early‐Holocene deglaciation in the Ross Sea, Antarctica
Authors: Spector Perry , Stone John , Cowdery Seth G. , Hall Brenda , Conway Howard , Bromley Gordon 
Published: July 2017

AbstractDeglaciation of the Ross Sea following the last ice age provides an important opportunity to examine the stability of marine ice sheets and their susceptibility to changing environmental conditions. Insufficient chronology for Ross Sea deglaciation has helped sustain (i) the theory that this region contributed significantly to Meltwater Pulse 1A (MWP‐1A) and (ii) the idea that Ross Sea grounding‐line retreat occurred in a “swinging gate” pattern hinged north of Roosevelt Island. We present deglaciation records from southern Transantarctic Mountain glaciers, which delivered ice to the central Ross Sea. Abrupt thinning of these glaciers 9–8 kyr B.P. coincided with deglaciation of the Scott Coast, ∼800 km to the north, and ended with the Ross Sea grounding line near Shackleton Glacier. This deglaciation removed grounded ice from most of the central and western Ross Sea in less than 2 kyr. The Ross Sea Sector neither contributed nor responded significantly to MWP‐1A.
Implications of the ammonia distribution on Jupiter from 1 to 100 bars as measured by the Juno microwave radiometer
Authors: Ingersoll Andrew P. , Adumitroaie Virgil , Allison Michael D. , Atreya Sushil , Bellotti Amadeo A. , Bolton Scott J. , Brown Shannon T. , Gulkis Samuel , Janssen Michael A. , Levin Steven M. , Li Cheng , Li Liming , Lunine Jonathan I. , Orton Glenn S. , Oyafuso Fabiano A. , Steffes Paul G. 
Published: July 2017

AbstractThe latitude‐altitude map of ammonia mixing ratio shows an ammonia‐rich zone at 0–5°N, with mixing ratios of 320–340 ppm, extending from 40–60 bars up to the ammonia cloud base at 0.7 bars. Ammonia‐poor air occupies a belt from 5–20°N. We argue that downdrafts as well as updrafts are needed in the 0–5°N zone to balance the upward ammonia flux. Outside the 0–20°N region, the belt‐zone signature is weaker. At latitudes out to ±40°, there is an ammonia‐rich layer from cloud base down to 2 bars that we argue is caused by falling precipitation. Below, there is an ammonia‐poor layer with a minimum at 6 bars. Unanswered questions include how the ammonia‐poor layer is maintained, why the belt‐zone structure is barely evident in the ammonia distribution outside 0–20°N, and how the internal heat is transported through the ammonia‐poor layer to the ammonia cloud base.
Classifying the tropospheric precursor patterns of sudden stratospheric warmings
Authors: Bao Ming , Tan Xin , Hartmann Dennis L. , Ceppi Paulo 
Published: July 2017

AbstractClassifying the tropospheric precursor patterns of sudden stratospheric warmings (SSWs) may provide insight into the different physical mechanisms of SSWs. Based on 37 major SSWs during the 1958–2014 winters in the ERA reanalysis data sets, the self‐organizing maps method is used to classify the tropospheric precursor patterns of SSWs. The cluster analysis indicates that one of the precursor patterns appears as a mixed pattern consisting of the negative‐signed Western Hemisphere circulation pattern and the positive phase of the Pacific‐North America pattern. The mixed pattern exhibits higher statistical significance as a precursor pattern of SSWs than other previously identified precursors such as the subpolar North Pacific low, Atlantic blocking, and the western Pacific pattern. Other clusters confirm northern European blocking and Gulf of Alaska blocking as precursors of SSWs. Linear interference with the climatological planetary waves provides a simple interpretation for the precursors. The relationship between the classified precursor patterns of SSWs and ENSO phases as well as the types of SSWs is discussed.
Short‐term variability in the ionosphere due to the nonlinear interaction between the 6 day wave and migrating tides
Authors: Gan Quan , Oberheide Jens , Yue Jia , Wang Wenbin 
Published: July 2017

AbstractUsing the thermosphere‐ionosphere‐mesosphere electrodynamics general circulation model simulations, we investigate the short‐term ionospheric variability due to the child waves and altered tides produced by the nonlinear interaction between the 6 day wave and migrating tides. Via the Fourier spectral diagnostics and least squares fittings, the [21 h, W2] and [13 h, W1] child waves, generated by the interaction of the 6 day wave with the DW1 and SW2, respectively, are found to play the leading roles on the subdiurnal variability (e.g., ±10 m/s in the ion drift and ~50% in the NmF2) in the F region vertical ion drift changes through the dynamo modulation induced by the low‐latitude zonal wind and the meridional wind at higher latitudes. The relatively minor contribution of the [11 h, W3] child wave is explicit as well. Although the [29 h, W0] child wave has the largest magnitude in the E region, its effect is totally absent in the vertical ion drift due to the zonally uniform structure. But the [29 h, W0] child wave shows up in the NmF2. It is found that the NmF2 short‐term variability is attributed to the wave modulations on both E region dynamo and in situ F region composition. Also, the altered migrating tides due to the interaction will not contribute to the ionospheric changes significantly.
Equatorial magnetic field of the near‐Earth magnetotail
Authors: Ohtani S. , Motoba T. 
Published: July 2017

AbstractThe equatorial magnetic field of the nightside magnetosphere is critical for understanding not only the configuration of the magnetotail but also its state and dynamics. The present study observationally addresses various aspects of the equatorial magnetic field, such as its spatial distribution, possible antisunward gradients, and extremely weak magnetic fields, with emphasis on the transition region between dipolar and stretched magnetic configurations. The results are summarized as follows: (1) the transition of the tail magnetic field from a near‐Earth dipolar configuration to a stretched one farther out takes place around −12 ≤ Xagsm ≤ −9 RE, although instantaneous configurations can vary significantly; (2) the average equatorial magnetic field in this transition region is noticeably weaker at solar minimum presumably reflecting weaker nightside magnetospheric currents closer to Earth; (3) the statistical comparison of equatorial magnetic fields measured simultaneously at two locations indicates that the gradient of the equatorial magnetic field is directed predominantly earthward, and it is suggested that apparent tailward gradients observed can be very often attributed to other factors such as structures in the Y direction and local fluctuations; (4) however, the gradient can be transiently directed tailward in association with the dipolarization of local magnetic field; (5) extremely weak (≤ 2 nT) magnetic fields are occasionally observed in the transition region during the substorm growth phase and during prolonged quiet intervals, but the association with steady magnetospheric convection, which was suggested before, cannot be confirmed possibly because of its rare occurrence.
Distributions, sources, and transformations of dissolved and particulate iron on the Ross Sea continental shelf during summer
Authors: Marsay Chris M. , Barrett Pamela M. , McGillicuddy Dennis J. , Sedwick Peter N. 
Published: July 2017

AbstractWe report water column dissolved iron (dFe) and particulate iron (pFe) concentrations from 50 stations sampled across the Ross Sea during austral summer (January–February) of 2012. Concentrations of dFe and pFe were measured in each of the major Ross Sea water masses, including the Ice Shelf Water and off‐shelf Circumpolar Deep Water. Despite significant lateral variations in hydrography, macronutrient depletion, and primary productivity across several different regions on the continental shelf, dFe concentrations were consistently low (<0.1 nM) in surface waters, with only a handful of stations showing elevated concentrations (0.20–0.45 nM) in areas of melting sea ice and near the Franklin Island platform. Across the study region, pFe associated with suspended biogenic material approximately doubled the inventory of bioavailable iron in surface waters. Our data reveal that the majority of the summertime iron inventory in the Ross Sea resides in dense shelf waters, with highest concentrations within 50 m of the seafloor. Higher dFe concentrations near the seafloor are accompanied by an increased contribution to pFe from authigenic and/or scavenged iron. Particulate manganese is also influenced by sediment resuspension near the seafloor but, unlike pFe, is increasingly associated with authigenic material higher in the water column. Together, these results suggest that following depletion of the dFe derived from wintertime convective mixing and sea ice melt, recycling of pFe in the upper water column plays an important role in sustaining the summertime phytoplankton bloom in the Ross Sea polynya.
Long‐term morphodynamics of muddy backbarrier basins: Fill in or empty out?
Authors: Mariotti G. , Canestrelli A. 
Published: July 2017

AbstractThe long‐term (3000 years) morphodynamics of an idealized muddy backbarrier tidal basins is studied using a shallow‐water hydrodynamics and wind‐wave model (Deltf3D‐FLOW‐WAVE), modified to include fully coupled marsh organogenic accretion, biostabilization, drag increase, and wave‐induced marsh edge erosion. The latter process is implemented with a novel probabilistic algorithm. Starting from an initially empty basin with a uniform bed slope, a network of channels incise the mudflat, sediment is released, and marshes establish at the basin landward margin. If enough mud is supplied to the basin from the shelf, marsh progradation counteracts marsh edge erosion and marshes expand. Marsh expansion does not completely fill the basin but leaves open a few km‐wide channels, large enough for waves to resuspend sediment. Starting from a basin (almost) filled with marshes, a drop in the external mud supply or an increase in the rate of relative sea level rise causes the basin to empty out by marsh edge erosion, while the marsh platform, aided by reworking of the sediment released by marsh retreat and mudflat deepening, keeps pace even with fast rates (10 mm/yr) of relative sea level rise. Even if the marsh does not drown, the marsh retreats faster if the rate of sea level rise increases, because more sediment is sequestered to fill the newly created accommodation space and is thus not available for marsh progradation. This study suggests that prediction of marsh erosion requires a basin‐scale sediment budget, and that edge erosion, not platform drowning, is likely to dominate marsh loss.
Abundance and morphometry changes across the high‐mountain lake‐size gradient in the tropical Andes of Southern Ecuador
Authors: Mosquera Pablo V. , Hampel Henrietta , Vázquez Raúl F. , Alonso Miguel , Catalan Jordi 
Published: July 2017

AbstractThe number, size, and shape of lakes are key determinants of the ecological functionality of a lake district. The lake area scaling relationships with lake number and volume enable upscaling biogeochemical processes and spatially considering organisms' metapopulation dynamics. These relationships vary regionally depending on the geomorphological context, particularly in the range of lake area <1 km2 and mountainous regions. The Cajas Massif (Southern Ecuador) holds a tropical mountain lake district with 5955 water bodies. The number of lakes deviates from a power law relationship with the lake area at both ends of the size range; similarly to the distributions found in temperate mountain ranges. The deviation of each distribution tail does not respond to the same cause. The marked relief limits the size of the largest lakes at high altitudes, whereas ponds are prompt to a complete infilling. A bathymetry survey of 202 lakes, selected across the full‐size range, revealed a volume‐area scaling coefficient larger than those found for other lake areas of glacial origin but softer relief. Water renewal time is not consistently proportional to the lake area due to the volume‐area variation in midsize lakes. The 85% of the water surface is in lakes >104 m2 and 50% of the water resources are held in a few ones (∼10) deeper than 18 m. Therefore, midlakes and large lakes are by far more biogeochemically relevant than ponds and shallow lakes in this tropical mountain lake district.
Criteria for designation with an “H” [MAK Value Documentation, 2014]
Authors: Hartwig A. ,   MAK Commission
Published: July 2017

Abstract

The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has evaluated criteria to designate substances with an “H” which can be absorbed via the skin in such amounts as to contribute significantly to systemic toxicity. Information on the uptake via the skin can be obtained from studies in humans, animals and from in vitro models preferably with human skin. Ideally, these data allow the calculation of a flux, i.e. the amount absorbed per cm
2
skin and hour. If these experimental studies are lacking, fluxes based on physicochemical data are calculated with three mathematical models for an aqueous saturated solution or a read‐across to similar substances with a better database is used. For gaseous substances, the water solubility of the substance is calculated at a substance concentration in the gas phase that corresponds to the MAK value and the flux is modelled.

An exposure time of one hour and an exposed skin area of 2000 cm
2
which corresponds to the area of both hands and forearms is used as a practical exposure model for liquids. For gases, the exposure time is taken as 8 hours and the exposed skin area as 1.8 m
2
.

With the obtained fluxes, the body burden is calculated and if it exceeds 25% of the chronic systemic NOAEL for workers, the substance is designated with an “H”. If the substance is genotoxic and no systemic NOAEL could be deduced, a qualitative proof of uptake is enough for the designation with an “H”.
Ethylacetat [MAK Value Documentation in German language, 2017]
Authors: Hartwig A. ,   MAK Commission
Published: July 2017

Abstract

The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re‐evaluated the maximum concentration at the workplace (MAK value) of ethyl acetate [
141‐78‐6
] of 400 ml/m
3
, considering all toxicological endpoints. Available publications and unpublished study reports are described in detail. The critical effect of ethyl acetate is irritation of eye and nose in humans and of the olfactory mucosa in rats; in addition, neurotoxic effects are observed in animals at high concentrations. In three studies with volunteers exposed to 400 ml ethyl acetate/m
3
, slight irritation in the nose, throat and eye were observed, however the physiological parameters blinking frequency and nasal resistance, both indicators of irritation were not affected. Overall, 400 ml ethyl acetate/m
3
is not an unequivocal NOAEC. Accordingly, the MAK value has been lowered to 200 ml/m
3
. As local effects are critical, the assignment to Peak Limitation Category I and the excursion factor of 2 are confirmed. Taking into consideration the data for the metabolites acetic acid and ethanol, damage to the embryo and fetus is unlikely when the MAK value for ethyl acetate is observed. Therefore, ethyl acetate remains classified in Pregnancy Risk Group C. Ethyl acetate is not genotoxic and there are no carcinogenicity studies. Skin contact is not expected to contribute significantly to systemic toxicity. Skin sensitization is not expected from the limited data. There are no data concerning the potential for respiratory sensitization.
Distillates (petroleum), hydrotreated light [MAK Value Documentation, 2016]
Authors: Hartwig A. ,   MAK Commission
Published: July 2017

Abstract

The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re‐evaluated the maximum concentration at the workplace (MAK value) of hydrotreated light distillates (petroleum) [
64742‐47‐8
] of 20 ml/m
3
, considering all toxicological endpoints. Available publications and unpublished study reports are described in detail. The critical effect of hydrotreated light distillates (petroleum) (C9–C16) vapours is presumably CNS‐depression as is the case with other hydrocarbon mixtures like White Spirit. For the aerosol phase lung toxicity is assumed to be the critical effect. The Commission increased the MAK value for the vapour phase to 50 ml/m
3
in analogy to hydrotreated heavy naphtha (petroleum) (C6–C13) for which behavioural studies with White Spirit (C9–C12) in volunteers were used to derive the MAK value. White Spirit can be viewed as representative for hydrotreated light distillates (petroleum) because their C13–C16 components have low vapour pressure and do not contribute much to the concentration in the vapour phase. On the other hand, the aerosol phase comprises mostly these components and they are expected to be deposited as aerosol in the lung. A MAK value of 5 mg/m
3
for the respirable fraction in analogy to White Oil is set. As systemic effects are critical, the assignment to Peak Limitation Category II is retained. The excursion factor of 2 for the vapour is confirmed and an excursion factor of 4 for the aerosol is set in analogy to White Oil. The assignment to Pregnancy Risk Group C is confirmed, as there is no reason to fear damage to the embryo or foetus when the MAK value is observed. Hydrotreated light distillates are not genotoxic. After chronic epicutaneous application of high doses of kerosenes malign skin tumours developed in mice. However, since the relevance of these tumours for humans in this model is not clear, the assignment to Carcinogen Category 3B is retained. Skin contact does not contribute to systemic toxicity and sensitization is not expected.