bluuebunny/crossref_metadata_2025 huggingface dataset:
An Ecocritical Reading of Paul Bowles's The Sheltering Sky
Authors: Sheikhzadeh Hossein , Bejarzehi Abdolghafour
Published: July 2017

Landscapes are not simply something objective and unchallenged out there but the work of the mind made by the strata of memory. This paper attempts to show that an ecocritical reading of Paul Bowles’s The Sheltering Sky (1949) helps one in better understanding of this novel of post-colonial alienation and existential despair. Bowles is an American writer and a composer who is undoubtedly the most arresting example of cross-cultural influence concerning a Western author and the Middle East and North Africa.  His fiction mostly focuses on American expatriates travelling in exotic locations. The Sheltering Sky is an encounter with the Sahara, not only the physical one but the desert of moral nihilism into which one may wander blindly. The boundless desert acts here as a metaphor and the journey symbolizes one’s own journey into the depth of his/her soul. The desert also projects an apocalyptic vision in the struggle between the West and the East and the Sahara becomes in fact a Conradian Heart of Darkness, an Eliotian Waste Land, and a Sartrean No Exit. In the novel the actual environment becomes in some ways pale and covert under the psyche of the writer. Consequently we come to know that Bowles's own knowledge and awareness of the same environments left traces in his work. Accordingly we may wrap up that the environment bears a direct impact on our understanding of it.
A Linguistic Analysis of the Aesthetics of Intertextuality in Habib Al-Zyoudi’s Poetry
Authors: Al-Khawaldeh Sami , N. Al-Khawaldeh Nisreen , Khawaldeh Imad
Published: July 2017

Intertextuality appears to be extremely important to better realize the different layers of the intended meaning of texts (Ahmadian and Yazdani, 2013). To the best of the researchers’ knowledge and considering its significance, very few studies were done on intertextuality in Arabic poetry (e.g. Bahar, 2014; Zawahreh, 2013 and Al-Khawaldeh et.al, 2016) and none was done on intertextuality in Habib Al-Zyoudi’s poetry. Thus, this study aims to highlight the aesthetics of the intertextuality in Habib Al-Zyoudi’s poetry. It particularly analyzes some examples of these salient embedded religious and literary texts, and highlights their positive impact on enriching the text besides illuminating some associated issues in modern Jordanian poetry. The content analysis of Al-Zyoudi’s poetry collections reveals how intertextuality helps the poet enrich the poetic notions of language and rhyme, raise readers’ awareness of the all-encompassing impact of cultural, religious, literary issues and figures on poetry which in turns aids readers to understand the intended meaning of the poems. Thus, the researchers recommend that translators have a proper background knowledge of religious, cultural, proverbial and poetical phases that might be typically different across languages.
Topicality as War News Value: A Pragma – Linguistic Study
Authors: Hameed Al-Hindawi Fareed , Huwail Ghayadh Hussein
Published: July 2017

This paper discusses one of the criteria of war news values in printed media. The current study concerns itself with only Topicality as the target of scrutiny. It explores this value through the application of a model of analysis based on a pragma-linguistic approach. The analysis is intended to achieve the following aims: first, bringing topicality as one criterion of news values to the attention of pragmatists; second, introducing an analytical framework which is hoped to be useful for pragmatists to analyze news values, and to be available in their hands for further development. This framework aims at explicitly revealing the linguistic as well as the pragmatic properties of the war news texts as far as topicality is concerned. In relation to the aims of the study and owing to the fact that people are eager to understand what is going on, it is hypothesized that topicality comes into viewable interaction between grammar and pragmatics. The findings of the data analysis indicate how topicality is transferred to the receiver of the message and how it shapes news reporting.
Student Readiness in Learning Arabic Language based on Blended Learning
Authors: Osman Norasyikin , Hamzah Mohd Isa
Published: July 2017

Learning with technology or e-learning has been taking place in all areas of education including in learning and teaching of Arabic language. Despite the widespread use of e-learning for Arabic language, in line with the current technological advancements, the role of face-to-face classroom interactions must not be neglected. Face-to-face learning and e-learning have their own strengths.  Hence, a combination of both elements in teaching and learning as afforded by blended learning may be an excellent choice. This study seeks to identify student readiness in learning Arabic language based on blended learning approach among students at university level.  The research took place at University Sultan Zainal Abidin (UniSZA), Malaysia involving 248 students.  The students were asked to answer the distributed questionnaires.  The questionnaires used 1-5 points Likert scale which are strongly not agree, not agree, not sure, agree and strongly agree. The need analysis encompassed the presence of facilities supporting blended learning, the internet and e-learning literacy among students and their readiness to adopt blended learning. The findings highlight the important roles played by both the students and the institution in providing facilities needed to support blended learning. The findings also reported that the existing facilities are in a state of readiness for the implementation of blended learning. The institution provides wireless connection throughout the campus while 96% of the students own a laptop. In addition, students are also discovered to be internet-savvy besides displaying readiness to adopt blended learning. Further studies are recommended in exploring how to design and develop successful blended learning in teaching and learning Arabic language.
13C based proteinogenic amino acid (PAA) and metabolic flux ratio analysis ofLactococcus lactisreveals changes in pentose phosphate (PP) pathway in response to agitation and temperature related stresses
Authors: Azizan Kamalrul Azlan , Ressom Habtom W. , Mendoza Eduardo R. , Baharum Syarul Nataqain
Published: July 2017

Lactococcus lactissubsp.cremorisMG1363 is an important starter culture for dairy fermentation. During industrial fermentations,L. lactisis constantly exposed to stresses that affect the growth and performance of the bacterium. Although the response ofL. lactisto several stresses has been described, the adaptation mechanisms at the level ofin vivofluxes have seldom been described. To gain insights into cellular metabolism,13C metabolic flux analysis and gas chromatography mass spectrometry (GC-MS) were used to measure the flux ratios of active pathways in the central metabolism ofL. lactiswhen subjected to three conditions varying in temperature (30°C, 37°C) and agitation (with and without agitation at 150 rpm). Collectively, the concentrations of proteinogenic amino acids (PAAs) and free fatty acids (FAAs) were compared, and Pearson correlation analysis (r) was calculated to measure the pairwise relationship between PAAs. Branched chain and aromatic amino acids, threonine, serine, lysine and histidine were correlated strongly, suggesting changes in flux regulation in glycolysis, the pentose phosphate (PP) pathway, malic enzyme and anaplerotic reaction catalysed by pyruvate carboxylase (pycA). Flux ratio analysis revealed that glucose was mainly converted by glycolysis, highlighting the stability ofL. lactis’central carbon metabolism despite different conditions. Higher flux ratios through oxaloacetate (OAA) from pyruvate (PYR) reaction in all conditions suggested the activation of pyruvate carboxylate (pycA) inL. lactis, in response to acid stress during exponential phase. Subsequently, more significant flux ratio differences were seen through the oxidative and non-oxidative pentose phosphate (PP) pathways, malic enzyme, and serine and C1 metabolism, suggesting NADPH requirements in response to environmental stimuli. These reactions could play an important role in optimization strategies for metabolic engineering inL. lactis. Overall, the integration of systematic analysis of amino acids and flux ratio analysis provides a systems-level understanding of howL. lactisregulates central metabolism under various conditions.
Predicting suitable habitat of the Chinese monal (Lophophorus lhuysii) using ecological niche modeling in the Qionglai Mountains, China
Authors: Wang Bin , Xu Yu , Ran Jianghong
Published: July 2017

Understanding the distribution and the extent of suitable habitats is crucial for wildlife conservation and management. Knowledge is limited regarding the natural habitats of the Chinese monal (Lophophorus lhuysii), which is a vulnerable Galliform species endemic to the high-montane areas of southwest China and a good candidate for being an umbrella species in the Qionglai Mountains. Using ecological niche modeling, we predicted current potential suitable habitats for the Chinese monal in the Qionglai Mountains with 64 presence points collected between 2005 and 2015. Suitable habitats of the Chinese monal were associated with about 31 mm precipitation of the driest quarter, about 15 °C of maximum temperature of the warmest month, and far from the nearest human residential locations (>5,000 m). The predicted suitable habitats of the Chinese monal covered an area of 2,490 km2, approximately 9.48% of the Qionglai Mountains, and was highly fragmented. 54.78% of the suitable habitats were under the protection of existing nature reserves and two conservation gaps were found. Based on these results, we provide four suggestions for the conservation management of the Chinese monal: (1) ad hoc surveys targeting potential suitable habitats to determine species occurrence, (2) more ecological studies regarding its dispersal capacity, (3) establishment of more corridors and green bridges across roads for facilitating species movement or dispersal, and (4) minimization of local disturbances.
A new terrestrial snail species (Gastropoda: Bulimulidae) from the Región de Antofagasta, northern Chile
Authors: Araya Juan Francisco , Breure Abraham S.H.
Published: July 2017

A new species ofScutalusAlbers, 1850 (Gastropoda: Bulimulidae),Scutalus changosp. n., is described from a coastal area of northern Chile. Empty shells of this new species were found buried in sand and under boulders and rocks in the foothills of the Chilean Coastal Range at Paposo, Región de Antofagasta. This new species is distinguished from all other Chilean terrestrial snails by its slender shell with a flared and reflected aperture, and by the presence of a columellar fold. This is the first record ofScutalusin Chile, and the southernmost record for this endemic South American bulimulid genus. The presence of this species in Paposo highlights the need for further research and for conservation guidelines in coastal areas of northern Chile, which have comparatively high levels of biodiversity and endemism.
Air‐sea interaction regimes in the sub‐Antarctic Southern Ocean and Antarctic marginal ice zone revealed by icebreaker measurements
Authors: Yu Lisan , Jin Xiangze , Schulz Eric W. , Josey Simon A.
Published: July 2017

This study analyzed shipboard air‐sea measurements acquired by the icebreaker Aurora Australis during its off‐winter operation in December 2010 to May 2012. Mean conditions over 7 months (October–April) were compiled from a total of 22 ship tracks. The icebreaker traversed the water between Hobart, Tasmania, and the Antarctic continent, providing valuable in situ insight into two dynamically important, yet poorly sampled, regimes: the sub‐Antarctic Southern Ocean and the Antarctic marginal ice zone (MIZ) in the Indian Ocean sector. The transition from the open water to the ice‐covered surface creates sharp changes in albedo, surface roughness, and air temperature, leading to consequential effects on air‐sea variables and fluxes. Major effort was made to estimate the air‐sea fluxes in the MIZ using the bulk flux algorithms that are tuned specifically for the sea‐ice effects, while computing the fluxes over the sub‐Antarctic section using the COARE3.0 algorithm. The study evidenced strong sea‐ice modulations on winds, with the southerly airflow showing deceleration (convergence) in the MIZ and acceleration (divergence) when moving away from the MIZ. Marked seasonal variations in heat exchanges between the atmosphere and the ice margin were noted. The monotonic increase in turbulent latent and sensible heat fluxes after summer turned the MIZ quickly into a heat loss regime, while at the same time the sub‐Antarctic surface water continued to receive heat from the atmosphere. The drastic increase in turbulent heat loss in the MIZ contrasted sharply to the nonsignificant and seasonally invariant turbulent heat loss over the sub‐Antarctic open water.
Effects of a shallow flood shoal and friction on hydrodynamics of a multiple‐inlet system
Authors: Orescanin Mara M. , Elgar Steve , Raubenheimer Britt , Gorrell Levi
Published: July 2017

Prior studies have shown that frictional changes owing to evolving geometry of an inlet in a multiple inlet‐bay system can affect tidally driven circulation. Here, a step between a relatively deep inlet and a shallow bay also is shown to affect tidal sea‐level fluctuations in a bay connected to multiple inlets. To examine the relative importance of friction and a step, a lumped element (parameter) model is used that includes tidal reflection from the step. The model is applied to the two‐inlet system of Katama Inlet (which connects Katama Bay on Martha's Vineyard, MA to the Atlantic Ocean) and Edgartown Channel (which connects the bay to Vineyard Sound). Consistent with observations and previous numerical simulations, the lumped element model suggests that the presence of a shallow flood shoal limits the influence of an inlet. In addition, the model suggests an increasing importance of friction relative to the importance of the step as an inlet shallows, narrows, and lengthens, as observed at Katama Inlet from 2011 to 2014.
Structure of the buoyant plume formed by Ob and Yenisei river discharge in the southern part of the Kara Sea during summer and autumn
Authors: Osadchiev A. A. , Izhitskiy A. S. , Zavialov P. O. , Kremenetskiy V. V. , Polukhin A. A. , Pelevin V. V. , Toktamysova Z. M.
Published: July 2017

This article focuses on the interaction between the Ob‐ and Yenisei‐dominated parts of the large Ob‐Yenisei buoyant plume formed in the southern part of the Kara Sea during ice‐free periods. It was shown that certain wind forcing and river discharge conditions cause the formation of a specific structure of the Ob‐Yenisei plume with significantly different properties of the Ob‐ and Yenisei‐dominated water masses. Under these conditions, the Yenisei runoff generates a narrow coastal current propagating northward from the Yenisei Gulf along the Taymyr Peninsula, which is isolated by the Ob‐dominated water mass from ambient sea water. As a result, the low‐salinity Yenisei‐dominated water mass occupies a relatively small area, while more saline Ob‐dominated water mass spreads over a wide area between the Gulf of Ob and the Taymyr Peninsula. The formation of the “isolation” configuration of the Ob‐Yenisei plume described above is presumed to be caused by the eastward Ekman transport and the resulting downwelling flow of the Ob‐dominated waters under the low‐saline and warm Yenisei‐dominated waters along the Taymyr Peninsula. Based on satellite imagery, wind reanalysis, and river discharge data collected and derived for the period of 2005–2011, it was estimated that the “isolation” configuration is regularly formed during late summer and autumn when the Ob discharge to the Kara Sea exceeds the Yenisei discharge and the local atmospheric circulation is dominated by the northerly wind regime. Assessment of the frequency and duration of the occurrence of the “isolation” configuration showed their synoptic time scale and significant interannual variability.
Bayesian spectral likelihood for hydrological parameter inference
Authors: Schaefli Bettina , Kavetski Dmitri
Published: July 2017

This paper proposes a spectral domain likelihood function for the Bayesian estimation of hydrological model parameters from a time series of model residuals. The spectral domain error model is based on the power‐density spectrum (PDS) of the stochastic process assumed to describe residual errors. The Bayesian spectral domain likelihood (BSL) is mathematically equivalent to the corresponding Bayesian time domain likelihood (BTL) and yields the same inference when all residual error assumptions are satisfied (and all residual error parameters are inferred). However, the BSL likelihood function does not depend on the residual error distribution in the original time domain, which offers a theoretical advantage in terms of robustness for hydrological parameter inference. The theoretical properties of BSL are demonstrated and compared to BTL and a previously proposed spectral likelihood by Montanari and Toth (2007), using a set of synthetic case studies and a real case study based on the Leaf River catchment in the U.S. The empirical analyses confirm the theoretical properties of BSL when applied to heteroscedastic and autocorrelated error models (where heteroscedasticity is represented using the log‐transformation and autocorrelation is represented using an AR(1) process). Unlike MTL, the use of BSL did not introduce additional parametric uncertainty compared to BTL. Future work will explore the application of BSL to challenging modeling scenarios in arid catchments and “indirect” calibration with nonconcomitant input/output time series.
The costs of delay in infrastructure investments: A comparison of 2001 and 2014 household water supply coping costs in the Kathmandu Valley, Nepal
Authors: Gurung Yogendra , Zhao Jane , Kumar KC Bal , Wu Xun , Suwal Bhim , Whittington Dale
Published: July 2017

In 2001, we conducted a survey of 1500 randomly sampled households in Kathmandu to determine the costs people were incurring to cope with Kathmandu's poor quality, unreliable piped water supply system. From 2001 until 2014, there was little additional public investment in the municipal water supply system. In the summer of 2014, we attempted to reinterview all 1500 households in our 2001 sample to determine how they had managed to deal with the growing water shortage and the deteriorating condition of the piped water infrastructure in Kathmandu and to compare their coping costs in 2014 with those we first estimated in 2001. Average household coping costs more than doubled in real terms over the period from 2001 to 2014, from US$5 to US$12 per month (measured in 2014 prices). The composition of household coping costs changed from 2001 to 2014, as households responded to the deteriorating condition of the piped water infrastructure by drilling more private wells, purchasing water from both tanker truck and bottled water vendors, and installing more storage tanks. These investments and expenditures resulted in a decline in the time households spend collecting water from outside the home. Our analysis suggests that the significant increase in coping costs between 2001 and 2014 may provide an opportunity for the municipal water utility to substantially increase water tariffs if the quantity and quality of piped services can be improved. However, the capital investments made by some households in private wells, pumping and treatment systems, and storage tanks in response to the delay in infrastructure investment may lock them into current patterns of water use, at least in the short run, and thus make it difficult to predict how they would respond to tariff increases for improved piped water services.
Predicting nonstationary flood frequencies: Evidence supports an updated stationarity thesis in the United States
Authors: Luke Adam , Vrugt Jasper A. , AghaKouchak Amir , Matthew Richard , Sanders Brett F.
Published: July 2017

Nonstationary extreme value analysis (NEVA) can improve the statistical representation of observed flood peak distributions compared to stationary (ST) analysis, but management of flood risk relies on predictions of out‐of‐sample distributions for which NEVA has not been comprehensively evaluated. In this study, we apply split‐sample testing to 1250 annual maximum discharge records in the United States and compare the predictive capabilities of NEVA relative to ST extreme value analysis using a log‐Pearson Type III (LPIII) distribution. The parameters of the LPIII distribution in the ST and nonstationary (NS) models are estimated from the first half of each record using Bayesian inference. The second half of each record is reserved to evaluate the predictions under the ST and NS models. The NS model is applied for prediction by (1) extrapolating the trend of the NS model parameters throughout the evaluation period and (2) using the NS model parameter values at the end of the fitting period to predict with an updated ST model (uST). Our analysis shows that the ST predictions are preferred, overall. NS model parameter extrapolation is rarely preferred. However, if fitting period discharges are influenced by physical changes in the watershed, for example from anthropogenic activity, the uST model is strongly preferred relative to ST and NS predictions. The uST model is therefore recommended for evaluation of current flood risk in watersheds that have undergone physical changes. Supporting information includes a MATLAB® program that estimates the (ST/NS/uST) LPIII parameters from annual peak discharge data through Bayesian inference.
Methane emission through ebullition from an estuarine mudflat: 2. Field observations and modeling of occurrence probability
Authors: Chen Xi , Schäfer Karina V. R. , Slater Lee
Published: July 2017

Ebullition can transport methane (CH4) at a much faster rate than other pathways, albeit over limited time and area, in wetland soils and sediments. However, field observations present large uncertainties in ebullition occurrences and statistic models are needed to describe the function relationship between probability of ebullition occurrence and water level changes. A flow‐through chamber was designed and installed in a mudflat of an estuarine temperate marsh. Episodic increases in CH4 concentration signaling ebullition events were observed during ebbing tides (15 events over 456 ebbing tides) and occasionally during flooding tides (4 events over 455 flooding tides). Ebullition occurrence functions were defined using logistic regression as the relative initial and end water levels, as well as tidal amplitudes were found to be the key functional variables related to ebullition events. Ebullition of methane was restricted by a surface frozen layer during winter; melting of this layer during spring thaw caused increases in CH4 concentration, with ebullition fluxes similar to those associated with large fluctuations in water level around spring tides. Our findings suggest that initial and end relative water levels, in addition to tidal amplitude, partly regulate ebullition events in tidal wetlands, modulated by the lunar cycle, storage of gas bubbles at different depths and seasonal changes in the surface frozen layer. Maximum tidal strength over a few days, rather than hourly water level, may be more closely associated with the possibility of ebullition occurrence as it represents a trade‐off time scale in between hourly and lunar periods.
Information theory‐based decision support system for integrated design of multivariable hydrometric networks
Authors: Keum Jongho , Coulibaly Paulin
Published: July 2017

Adequate and accurate hydrologic information from optimal hydrometric networks is an essential part of effective water resources management. Although the key hydrologic processes in the water cycle are interconnected, hydrometric networks (e.g., streamflow, precipitation, groundwater level) have been routinely designed individually. A decision support framework is proposed for integrated design of multivariable hydrometric networks. The proposed method is applied to design optimal precipitation and streamflow networks simultaneously. The epsilon‐dominance hierarchical Bayesian optimization algorithm was combined with Shannon entropy of information theory to design and evaluate hydrometric networks. Specifically, the joint entropy from the combined networks was maximized to provide the most information, and the total correlation was minimized to reduce redundant information. To further optimize the efficiency between the networks, they were designed by maximizing the conditional entropy of the streamflow network given the information of the precipitation network. Compared to the traditional individual variable design approach, the integrated multivariable design method was able to determine more efficient optimal networks by avoiding the redundant stations. Additionally, four quantization cases were compared to evaluate their effects on the entropy calculations and the determination of the optimal networks. The evaluation results indicate that the quantization methods should be selected after careful consideration for each design problem since the station rankings and the optimal networks can change accordingly.
Modeling the probability distribution of peak discharge for infiltrating hillslopes
Authors: Baiamonte Giorgio , Singh Vijay P.
Published: July 2017

Hillslope response plays a fundamental role in the prediction of peak discharge at the basin outlet. The peak discharge for the critical duration of rainfall and its probability distribution are needed for designing urban infrastructure facilities. This study derives the probability distribution, denoted as GABS model, by coupling three models: (1) the Green‐Ampt model for computing infiltration, (2) the kinematic wave model for computing discharge hydrograph from the hillslope, and (3) the intensity‐duration‐frequency (IDF) model for computing design rainfall intensity. The Hortonian mechanism for runoff generation is employed for computing the surface runoff hydrograph. Since the antecedent soil moisture condition (ASMC) significantly affects the rate of infiltration, its effect on the probability distribution of peak discharge is investigated. Application to a watershed in Sicily, Italy, shows that with the increase of probability, the expected effect of ASMC to increase the maximum discharge diminishes. Only for low values of probability, the critical duration of rainfall is influenced by ASMC, whereas its effect on the peak discharge seems to be less for any probability. For a set of parameters, the derived probability distribution of peak discharge seems to be fitted by the gamma distribution well. Finally, an application to a small watershed, with the aim to test the possibility to arrange in advance the rational runoff coefficient tables to be used for the rational method, and a comparison between peak discharges obtained by the GABS model with those measured in an experimental flume for a loamy‐sand soil were carried out.
A soil column model for predicting the interaction between water table and evapotranspiration
Authors: Maquin Mathilde , Mouche Emmanuel , Mügler Claude , Pierret Marie‐Claire , Viville Daniel
Published: July 2017

Lateral waterfluxes are not realistically taken into account in soil column models, although they influence the dynamic evolution of the vertical soil moisture profile. By neglecting these fluxes, the modeling of the soil‐vegetation‐atmosphere continuum is incomplete, and the feedbacks between these three compartments cannot be fully simulated. These fluxes have an importance in the different fields where soil column models are used: hydrology, hydrometeorology, biogeochemical cycles, ecology, and soil weathering. This paper introduces a novel Hydrological Hillslope‐based Soil Column model (H2SC) that simulates the temporal evolution of the water table depth and evapotranspiration fluxes and their interaction. The interconnected processes are infiltration, evapotranspiration, vertical soil water movements, and the nonexplicitly modeled lateral fluxes flowing through the soil column. These lateral fluxes are modeled as a drainage function built from physically based equations that describe a simplified hillslope hydrology. This drainage function can be easily implemented in any soil column model without penalizing computational times. The H2SC model was validated on numerical experiments where a 2‐D hillslope simulation performed with an integrated hydrologic model was compared with simulations using the H2SC 1‐D model. Each of the H2SC simulations represents a specific location of a soil column along the hillslope. Different climate forcings, soil properties, and geometric shapes of the hillslope were tested. The model was then applied at the locations of two piezometers in the Strengbach catchment, France. The model reproduced the temporal evolution of the water table level fairly well for both the numerical experiments and for the real test case.
The mechanics of shallow magma reservoir outgassing
Authors: Parmigiani A. , Degruyter W. , Leclaire S. , Huber C. , Bachmann O.
Published: July 2017

Magma degassing fundamentally controls the Earth's volatile cycles. The large amount of gas expelled into the atmosphere during volcanic eruptions (i.e., volcanic outgassing) is the most obvious display of magmatic volatile release. However, owing to the large intrusive:extrusive ratio, and considering the paucity of volatiles left in intrusive rocks after final solidification, volcanic outgassing likely constitutes only a small fraction of the overall mass of magmatic volatiles released to the Earth's surface. Therefore, as most magmas stall on their way to the surface, outgassing of uneruptible, crystal‐rich magma storage regions will play a dominant role in closing the balance of volatile element cycling between the mantle and the surface. We use a numerical approach to study the migration of a magmatic volatile phase (MVP) in crystal‐rich magma bodies (“mush zones”) at the pore scale. Our results suggest that buoyancy‐driven outgassing is efficient over crystal volume fractions between 0.4 and 0.7 (for mm‐sized crystals). We parameterize our pore‐scale results for MVP migration in a thermomechanical magma reservoir model to study outgassing under dynamical conditions where cooling controls the evolution of the proportion of crystal, gas, and melt phases and to investigate the role of the reservoir size and the temperature‐dependent viscoelastic response of the crust on outgassing efficiency. We find that buoyancy‐driven outgassing allows for a maximum of 40–50% volatiles to leave the reservoir over the 0.4–0.7 crystal volume fractions, implying that a significant amount of outgassing must occur at high crystal content (>0.7) through veining and/or capillary fracturing.
Global rates of mantle serpentinization and H2 production at oceanic transform faults in 3‐D geodynamic models
Authors: Rüpke Lars H. , Hasenclever Jörg
Published: July 2017

Previous studies have estimated that mantle serpentinization reactions generate H2 at a rate of 1010–1012 mol/yr along the global mid‐ocean ridge (MOR) system. Here we present results of 3‐D geodynamic simulations that predict rates of additional mantle serpentinization and H2 production at oceanic transform faults (OTF). We find that the extent and rate of mantle serpentinization increases with OTF length and is maximum at intermediate slip rates of 5 to 10 cm/yr. The additional global OTF‐related production of H2 is found to be between 6.1 and 10.7 × 1011 mol/yr, which is comparable to the predicted background MOR rate of 4.1–15.0 × 1011 mol H2/yr. This points to oceanic transform faults as potential sites of intense fluid‐rock interaction, where chemosynthetic life could be sustained by serpentinization reactions.
Spatiotemporal evolution of the 2011 Prague, Oklahoma, aftershock sequence revealed using subspace detection and relocation
Authors: McMahon Nicole D. , Aster Richard C. , Yeck William L. , McNamara Daniel E. , Benz Harley M.
Published: July 2017

The 6 November 2011 Mw 5.7 earthquake near Prague, Oklahoma, is the second largest earthquake ever recorded in the state. A Mw 4.8 foreshock and the Mw 5.7 mainshock triggered a prolific aftershock sequence. Utilizing a subspace detection method, we increase by fivefold the number of precisely located events between 4 November and 5 December 2011. We find that while most aftershock energy is released in the crystalline basement, a significant number of the events occur in the overlying Arbuckle Group, indicating that active Meeker‐Prague faulting extends into the sedimentary zone of wastewater disposal. Although the number of aftershocks in the Arbuckle Group is large, comprising ~40% of the aftershock catalog, the moment contribution of Arbuckle Group earthquakes is much less than 1% of the total aftershock moment budget. Aftershock locations are sparse in patches that experienced large slip during the mainshock.
Survey of Saturn electrostatic cyclotron harmonic wave intensity
Authors: Menietti J. D. , Averkamp T. F. , Kurth W. S. , Ye S.‐Y. , Gurnett D. A. , Cecconi B.
Published: July 2017

We conduct a survey of electrostatic electron cyclotron harmonic (ECH) emissions observed at Saturn by the radio and plasma wave science investigation on board the Cassini spacecraft. These emissions are known to be effective at interacting with electrons in the terrestrial inner magnetosphere, producing electron scattering into the loss cone and acceleration (cf. Horne and Thorne, 2000; Thorne et al., 2010). At Saturn ECH emission occurs with high probability and at strong intensity near the magnetic equator, outside the Enceladus torus in the range ~5 < L < ~10. Inside the inner boundary of the torus, ECH emissions are also observed near the equator and at higher latitude. Intensity levels of ECH emission are comparable to those observed at Earth, higher than Saturn chorus and Z‐mode emission, and are likely to scatter electrons into the loss cone as at Earth. ECH waves are particularly intense and extend to higher harmonics within some plasma injection regions. We present results for a survey of over 8 years of Saturn data for fundamental and up to three harmonics of fce, the electron cyclotron frequency.
Survey of Voyager plasma science ions at Jupiter: 2. Heavy ions
Authors: Dougherty L. P. , Bodisch K. M. , Bagenal F.
Published: July 2017

We take the plasma parameters derived by Bagenal et al. (2017) from Voyager plasma science data in the Jovian magnetosphere and examine the radial profiles of density, temperature, composition, and azimuthal flow. The plasma sheet shows a relatively uniform structure of decreasing electron density (Ne) and increasing temperature out to about 20 RJ, but beyond about 15 RJ there is increasing disorder with sporadic blobs of cold plasma. These small (~0.5 RJ) blobs of cold (~20 eV) plasma make a minor contribution to the net outward flux of iogenic plasma. The ion composition in the cold blobs is consistent with the ion abundances derived from physical chemistry models extending from 6 to ~9 RJ, whereupon the collisional reactions slow down and radial transport speeds up, effectively freezing in the ion composition to the following abundances: O+/Ne = 15–22%, S++/Ne = 10–19%, O++/Ne = 4–8%, S+++/Ne = 4–6%, and S+/Ne = 1–5%. Beyond about 7 RJ the component of hot (suprathermal, approximately hundreds of eV) ions becomes a significant fraction of the total density. The radial profile of the plasma's azimuthal flow speed shows that corotation begins to breakdown at about 9 RJ, dipping down to about 20% below corotation before increasing back up to corotation briefly (~17–20 RJ), reaching an asymptotic value of about 225 km/s (corresponding to rigid corotation at ~18 RJ). We present a 2‐D model of the plasma sheet beyond 6 RJ based on simple functions for the equatorial profiles of plasma properties and steady state diffusive equilibrium along magnetic flux tubes. Cold plasma blobs in the Jovian plasma sheet show ion composition consistent with physical chemistry models. Azimuthal flow speeds dip below corotation 9–15 Jovian radii. Radial profiles of plasma properties are combined to make a 2‐D model of plasma sheet.
On the imprint of surfactant‐driven stabilization of laboratory breaking wave foam with comparison to oceanic whitecaps
Authors: Callaghan A. H. , Deane G. B. , Stokes M. D.
Published: July 2017

Surfactants are ubiquitous in the global oceans: they help form the materially‐distinct sea surface microlayer (SML) across which global ocean‐atmosphere exchanges take place, and they reside on the surfaces of bubbles and whitecap foam cells prolonging their lifetime thus altering ocean albedo. Despite their importance, the occurrence, spatial distribution, and composition of surfactants within the upper ocean and the SML remains under‐characterized during conditions of vigorous wave breaking when in‐situ sampling methods are difficult to implement. Additionally, no quantitative framework exists to evaluate the importance of surfactant activity on ocean whitecap foam coverage estimates. Here we use individual laboratory breaking waves generated in filtered seawater and seawater with added soluble surfactant to identify the imprint of surfactant activity in whitecap foam evolution. The data show a distinct surfactant imprint in the decay phase of foam evolution. The area‐time‐integral of foam evolution is used to develop a time‐varying stabilization function,
and a stabilization factor,
, which can be used to identify and quantify the extent of this surfactant imprint for individual breaking waves. The approach is then applied to wind‐driven oceanic whitecaps, and the laboratory and ocean
distributions overlap. It is proposed that whitecap foam evolution may be used to determine the occurrence and extent of oceanic surfactant activity to complement traditional in‐situ techniques and extend measurement capabilities to more severe sea states occurring at wind speeds in excess of about 10 m/s. The analysis procedure also provides a framework to assess surfactant‐driven variability within and between whitecap coverage data sets.
Biogeochemical sensor performance in the SOCCOM profiling float array
Authors: Johnson Kenneth S. , Plant Joshua N. , Coletti Luke J. , Jannasch Hans W. , Sakamoto Carole M. , Riser Stephen C. , Swift Dana D. , Williams Nancy L. , Boss Emmanuel , Haëntjens Nils , Talley Lynne D. , Sarmiento Jorge L.
Published: July 2017

The Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) program has begun deploying a large array of biogeochemical sensors on profiling floats in the Southern Ocean. As of February 2016, 86 floats have been deployed. Here the focus is on 56 floats with quality‐controlled and adjusted data that have been in the water at least 6 months. The floats carry oxygen, nitrate, pH, chlorophyll fluorescence, and optical backscatter sensors. The raw data generated by these sensors can suffer from inaccurate initial calibrations and from sensor drift over time. Procedures to correct the data are defined. The initial accuracy of the adjusted concentrations is assessed by comparing the corrected data to laboratory measurements made on samples collected by a hydrographic cast with a rosette sampler at the float deployment station. The long‐term accuracy of the corrected data is compared to the GLODAPv2 data set whenever a float made a profile within 20 km of a GLODAPv2 station. Based on these assessments, the fleet average oxygen data are accurate to 1 ± 1%, nitrate to within 0.5 ± 0.5 µmol kg−1, and pH to 0.005 ± 0.007, where the error limit is 1 standard deviation of the fleet data. The bio‐optical measurements of chlorophyll fluorescence and optical backscatter are used to estimate chlorophyll a and particulate organic carbon concentration. The particulate organic carbon concentrations inferred from optical backscatter appear accurate to with 35 mg C m−3 or 20%, whichever is larger. Factors affecting the accuracy of the estimated chlorophyll a concentrations are evaluated.
Revisiting Ocean Color algorithms for chlorophyll a and particulate organic carbon in the Southern Ocean using biogeochemical floats
Authors: Haëntjens Nils , Boss Emmanuel , Talley Lynne D.
Published: July 2017

The Southern Ocean (SO) ecosystem plays a key role in the carbon cycle by sinking a major part (43%) of the ocean uptake of anthropogenic CO2, and being an important source of nutrients for primary producers. However, undersampling of SO biogeochemical properties limits our understanding of the mechanisms taking place in this remote area. The Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) project has been deploying a large number of autonomous biogeochemical floats to study the SO (as of December 2016, 74 floats out of 200 have been deployed). SOCCOM floats measurements can be used to extend remote sensing chlorophyll a (chl a) and particulate organic carbon (POC) products under clouds or during the polar night as well as adding the depth dimension to the satellite‐based view of the SO. Chlorophyll a concentrations measured by a sensor embedded on the floats and POC concentrations derived from backscattering coefficients were calibrated with samples collected during the floats' deployment cruise. Float chl a and POC were compared with products derived from observations of MODIS and VIIRS sensors. We find the Ocean Color Index (OCI) global algorithm to agree well with the matchups (within 9%, on average, for the Visible Infrared Imaging Radiometer Suite (VIIRS) and 12%, on average, for the Moderate Resolution Imaging Spectroradiometer Aqua (MODIS)). SO‐specific algorithms estimating chl a are offset by ∼45% south of the Sea Ice Extent Front (
°S). In addition, POC estimates based on floats agree well with NASA's POC algorithm.
Equatorial Kelvin waves generated in the western tropical Pacific Ocean trigger mass and heat transport within the Middle America Trench off Costa Rica
Authors: Thomson Richard E. , Davis Earl E.
Published: July 2017

Sequences of correlated seafloor temperature, current velocity, and acoustic backscatter events recorded at Ocean Drilling Program (ODP) sites at 4300 m depth in the Middle America Trench have been inferred to result from tidally induced turbidity currents generated in the vicinity of the 3300 m deep sill at the southern end of the trench. New data from the borehole observatories extend the temperature records to 11 years (November 2002 to December 2013) and confirm the highly episodic nature of the events. We present satellite altimetry data and ocean circulation model results to show that event timing is correlated with intraseasonal Kelvin wave motions in the equatorial Pacific. The observed temperature events had a mean (±1 standard deviation) occurrence interval of 61 (±24) days, which spans the periods of the first two baroclinic modes. Lag times between peak bottom water temperatures at the ODP sites and the passage of eastward‐propagating Kelvin wave crests at locations in the eastern equatorial Pacific are consistent with the time for mode‐1 waves to propagate to the southern end of the trench at a mean phase speed of 2.0 m s−1. Findings indicate that Kelvin wave currents augment tidal motions in the vicinity of the sill, triggering turbidity currents that travel northwestward along the trench axis at mean speeds of ∼0.1 m s−1. We conclude that mode‐1 (or, possibly, mixed mode‐1 and mode‐2) baroclinic Kelvin waves generated by large‐scale atmospheric processes in the western tropical Pacific lead to heat and mass transport deep within Middle America Trench in the eastern tropical Pacific.
Testing a common ice‐ocean parameterization with laboratory experiments
Authors: McConnochie C. D. , Kerr R. C.
Published: July 2017

Numerical models of ice‐ocean interactions typically rely upon a parameterization for the transport of heat and salt to the ice face that has not been satisfactorily validated by observational or experimental data. We compare laboratory experiments of ice‐saltwater interactions to a common numerical parameterization and find a significant disagreement in the dependence of the melt rate on the fluid velocity. We suggest a resolution to this disagreement based on a theoretical analysis of the boundary layer next to a vertical heated plate, which results in a threshold fluid velocity of approximately 4 cm/s at driving temperatures between 0.5 and C, above which the form of the parameterization should be valid.
Three‐dimensional transient rip currents: Bathymetric excitation of low‐frequency intrinsic variability
Authors: Uchiyama Yusuke , McWilliams James C. , Akan Cigdem
Published: July 2017

The ROMS‐WEC model [Uchiyama et al., 2010] based on an Eulerian wave‐averaged vortex‐force asymptotic theory of McWilliams et al. (2004) is applied to analyze 3‐D transient wave‐driven rip currents and associated intrinsic very low‐frequency (VLF) variability in the surf zone on a surveyed bathymetry under spatiotemporally uniform offshore incident waves. The 3‐D rip currents are substantially depth‐dependent due to the vertical recirculation, composed of pairs of counter‐rotating longitudinal overturning roll cells that promote surface convergence. The vortex force plays an important role in vorticity budget, preconditioning overall vorticity reduction. These rip currents are intrinsically unstable and contribute about 70% to kinetic energy (KE) as eddy kinetic energy (EKE), consistent with observations. The dominant fluctuation period fits the VLF band, at about 18 min. The current effect on waves (CEW) alters not only the mean rip structure, but also the associated turbulence as the modified cross‐shore EKE profile with considerable accentuation in the inner surf zone. Increased alongshore bathymetric variability proportionally intensifies KE and intrinsic EKE, whereas it reduces the VLF period. With a guide of a pseudo 2D model, we reveal that vortex tilting effect due to the horizontal vorticity inherent in the 3‐D rip currents promotes collapse of the 3‐D eddies through an enhanced forward kinetic energy cascade, leading to short‐lived, laterally‐stretched 3‐D eddies resulting in elongated filaments that decay more quickly than coherent, long‐lived, circular 2‐D eddies.
Sedimentary processes of the Bagnold Dunes: Implications for the eolian rock record of Mars
Authors: Ewing R. C. , Lapotre M. G. A. , Lewis K. W. , Day M. , Stein N. , Rubin D. M. , Sullivan R. , Banham S. , Lamb M. P. , Bridges N. T. , Gupta S. , Fischer W. W.
Published: July 2017

The Mars Science Laboratory rover Curiosity visited two active wind‐blown sand dunes within Gale crater, Mars, which provided the first ground‐based opportunity to compare Martian and terrestrial eolian dune sedimentary processes and study a modern analog for the Martian eolian rock record. Orbital and rover images of these dunes reveal terrestrial‐like and uniquely Martian processes. The presence of grainfall, grainflow, and impact ripples resembled terrestrial dunes. Impact ripples were present on all dune slopes and had a size and shape similar to their terrestrial counterpart. Grainfall and grainflow occurred on dune and large‐ripple lee slopes. Lee slopes were ~29° where grainflows were present and ~33° where grainfall was present. These slopes are interpreted as the dynamic and static angles of repose, respectively. Grain size measured on an undisturbed impact ripple ranges between 50 μm and 350 μm with an intermediate axis mean size of 113 μm (median: 103 μm). Dissimilar to dune eolian processes on Earth, large, meter‐scale ripples were present on all dune slopes. Large ripples had nearly symmetric to strongly asymmetric topographic profiles and heights ranging between 12 cm and 28 cm. The composite observations of the modern sedimentary processes highlight that the Martian eolian rock record is likely different from its terrestrial counterpart because of the large ripples, which are expected to engender a unique scale of cross stratification. More broadly, however, in the Bagnold Dune Field as on Earth, dune‐field pattern dynamics and basin‐scale boundary conditions will dictate the style and distribution of sedimentary processes.