bluuebunny/crossref_metadata_2025 huggingface dataset:
Production of 2,3‐butanediol by fermentation of enzymatic hydrolysed bagasse from agave mezcal‐waste using the native Klebsiella oxytoca UM2‐17 strain
Authors: Pasaye‐Anaya Lizbeth , Vargas‐Tah Alejandra , Martínez‐Cámara Christian , Castro‐Montoya Agustín J , Campos‐García Jesús
Published: August 2019

Background

2,3‐butanediol is a chemical component with wide industrial applications, such as biofuels and chemical precursors. Reducing 2,3‐butanediol production costs is a high priority and recent focus has been on its biological synthesis from raw renewable materials rather than through conventional chemical procedures. In this study, a 2,3‐butanediol native bacterial producer was selected for the fermentation of Agave cupreata bagasse waste by enzymatic hydrolysation to obtain 2,3‐butanediol.

Results

The native Klebsiella oxytoca UM2‐17 strain was selected to efficiently produce 2,3‐butanediol on synthetic mineral media. Using glucose (100 g L−1) and glucose: xylose (50 g L−1:50 g L−1) as sugar sources obtained titres of 29.36 g L−1 and 25.9 g L−1 of 2,3‐butanediol, corresponding to yields of 0.29 g g−1 and 0.26 g g−1, respectively. Agave bagasse solid waste after acid pre‐treatment was utilized to obtain enzymatic hydrolysates, obtaining liquors with glucose/xylose/arabinose at 25.8 g L−1 with efficiency of ∼52.5% sugar conversion from residual solid pre‐hydrolysed bagasse. The production of 2,3‐butanediol through batch fermentation of the enzymatic‐hydrolysate by the UM2‐17 strain showed total depletion of glucose and xylose, achieving a maximal production of 10.3 g L−1 of 2,3‐butanediol plus 0.28 g L−1 ethanol, corresponding to 2,3‐butanediol yield of 0.40 g g−1.

Conclusion

The results indicate that A. cupreata bagasse waste from mezcal beverage elaboration is a sustainable bioresource for production of 2,3‐butanediol by fermentation of enzymatic bagasse‐hydrolysate using the K. oxytoca UM2‐17 strain. © 2019 Society of Chemical Industry
Central nervous system complications in adult cystinosis patients
Authors: Servais Aude , Saitovitch Ana , Hummel Aurélie , Boisgontier Jennifer , Scemla Anne , Sberro‐Soussan Rebecca , Snanoudj Renaud , Lemaitre Hervé , Legendre Christophe , Pontoizeau Clément , Antignac Corinne , Anglicheau Dany , Funalot Benoît , Boddaert Nathalie
Published: August 2019

Little is known about the long‐term progression of adult nephropathic cystinosis patients. Our objective was to study central nervous system complications in cystinosis patients in the era of early cysteamine treatment, using advanced neuroimaging techniques. Neurological examination and multimodal brain 3 Tesla MRI were performed in 21 adult cystinosis patients, including 18 infantile cystinosis patients, 20 controls matched for age and renal function, and 12 healthy controls. Differences in gray matter volume and rest cerebral blood flow (CBF) using arterial spin labeling sequence were investigated using whole‐brain voxel‐based approach. Median age was 33.8 years (18.7‐65.8). Seven patients (38.9%) presented with at least one central nervous system clinical abnormality: two (11.1%) with seizures, three (16.7%) with memory defects, five (27.8%) with cognitive defect, and one (5.5%) with stroke‐like episode. These patients had a worse compliance to treatment (compliance score 2 vs 1, P = .03) and received a lower median cysteamine dose (0.9 g/day vs 2.1 g/day, P = .02). Among patients with infantile cystinosis, 13 (72.2%) showed cortical atrophy, which was absent in controls, but it was not correlated with symptoms. Cystinosis patients showed a significant gray matter decrease in the middle frontal gyrus compared with healthy controls and a significant negative correlation between the cystine blood level and rest CBF was observed in the right superior frontal gyrus, a region associated with executive function. Compliance to cysteamine treatment is a major concern in these adult patients and could have an impact on the development of neurological and cognitive complications.
Inter‐decadal and inter‐annual variability of meridional tropical cyclone activity during September–October in the northwestern North Pacific after 1998
Authors: Tu Jien‐Yi , Chen Jau‐Ming , Wu Liang , Chi Chia‐Zhen
Published: August 2019

This study examines inter‐decadal and inter‐annual variability of meridional tropical cyclone (TC) activity during September–October (SO) in the northwestern North Pacific (NWNP) around Taiwan after 1998. From inter‐decadal period 1 (1980–1997) to period 2 (1998–2017), the Pacific Decadal Oscillation (PDO) changes its phase from positive to negative, characterizing cold sea surface temperature (SST) anomalies in the tropical eastern Pacific and warm SST anomalies in the tropical western Pacific. An induced low‐level convergent centre around the Maritime Continent evokes a cyclonic anomaly on its northwestern side overlying Taiwan that facilitates TC formation in the region north of 20°N. These TCs later move northwards/northwestwards in association with a westwards extension of the western Pacific subtropical high, leading to inter‐decadal increase of northwards TC movements in the 120°–130°E region. For inter‐annual variability, TC passage frequency in the NWNP tends to decrease during El Niño events but to increase or decrease in La Niña‐related events. In La Niña‐related conditions, the low‐level anomalous convergent centre situating to the west of 130°E (east of 135°E) tends to increase (decrease) TC passage frequency in the NWNP around Taiwan. This region is influenced by an anomalous anticyclone (cyclone) on its eastern side that induces anomalous southeasterly (northeasterly) steering flows to facilitate (hinder) TC movement from the tropical western Pacific into this region. Inter‐annual and inter‐decadal variability of TC passage frequency in the NWNP is highly and positively connected with TC passage frequency and TC counts affecting Taiwan. More (less) TC passage frequency in the NWNP thus tends to relate to increased (decreased) TC rainfall in Taiwan.
Study on the spectrum‐effect relationship of the xanthine oxidase inhibitory activity of Ligustrum lucidum
Authors: Gao Sai , Chen Huaguo , Zhou Xin
Published: August 2019

To evaluate the xanthine oxidase inhibitory activity of the chemical constituents of Ligustrum lucidum in vitro, the spectrum‐effect relationship was investigated. The high‐performance liquid chromatography fingerprint was established by ultraviolet spectrophotometry, and the xanthine oxidase inhibitory activity was tested in vitro by a high‐throughput screening method. Cluster analysis, principal component analysis, gray correlation analysis, and partial least squares regression were used to explore the spectrum‐effect relationships. Sixty batches of Ligustrum lucidum were collected from 16 provinces for testing. The results revealed differences among the batches of medicinal materials, and the similarity score was between 0.635 and 0.968. Thirty‐three characteristic peaks (1–33) were calibrated by fingerprint evaluation software for traditional Chinese medicine. The spectrum‐effect relationship study further revealed that the contents of peaks 1, 2, 4, 5, 6, 7, 14, 17, 25, 28, 31, and 33, which are potentially critical ingredients for quality control of Ligustrum lucidum fruit, were highly correlated with the inhibition of xanthine oxidase activity.
Numerical experiments on a hybrid WENO5 filter for shock‐capturing
Authors: Mahmoodi Darian Hossein , Bozorgpour Reza , Shafaee Maziar
Published: August 2019

In the present paper, a hybrid filter is introduced for high accurate numerical simulation of shock‐containing flows. The fourth‐order compact finite difference scheme is used for the spatial discretization and the third‐order Runge–Kutta scheme is used for the time integration. After each time‐step, the hybrid filter is applied on the results. The filter is composed of a linear sixth‐order filter and the dissipative part of a fifth‐order weighted essentially nonoscillatory scheme (WENO5). The classic WENO5 scheme and the WENO5 scheme with adaptive order (WENO5‐AO) are used to form the hybrid filter. Using a shock‐detecting sensor, the hybrid filter reduces to the linear sixth‐order filter in smooth regions for damping high frequency waves and reduces to the WENO5 filter at shocks in order to eliminate unwanted oscillations produced by the nondissipative spatial discretization method. The filter performance and accuracy of the results are examined through several test cases including the advection, Euler and Navier–Stokes equations. The results are compared with that of a hybrid second‐order filter and also that of the WENO5 and WENO5‐AO schemes.
Convergence of a positive nonlinear control volume finite element scheme for an anisotropic seawater intrusion model with sharp interfaces
Authors: Ait Hammou Oulhaj Ahmed , Maltese David
Published: August 2019

We study a sharp interface model in the context of seawater intrusion in an anisotropic unconfined aquifer. It is a degenerate parabolic system with cross‐diffusion modeling the flow of fresh and saltwater. We study a nonlinear control volume finite element scheme. This scheme ensures the nonnegativity of the discrete solution without any restriction on the transmissibility coefficients. Moreover, it also provides a control on the entropy. The existence of a discrete solution and the convergence of this scheme are obtained, based on nonlinear stability results.
Confined crystallization morphology of poly(ϵ‐caprolactone) block within poly(ϵ‐caprolactone)–poly(l‐lactide) copolymers
Authors: Han Weiqiang , Li Shaojie , Liao Xia , He Bin , Yang Qi , Li Guangxian
Published: August 2019

The confined crystallization of poly(ϵ‐caprolactone) (PCL) block in poly(ϵ‐caprolactone)–poly(l‐lactide) (PCL‐PLLA) copolymers was investigated using differential scanning calorimetry, polarized optical microscopy, scanning electronic microscopy and atomic force microscopy. To study the effect of crystallization and molecular chain motion state of PLLA blocks in PCL‐PLLA copolymers on PCL crystallization morphology, high‐temperature annealing (180 °C) and low‐temperature annealing (80 °C) were applied to treat the samples. It was found that the crystallization morphology of PCL block in PCL‐PLLA copolymers is not only related to the ratio of block components, but also related to the thermal history. After annealing PCL‐PLLA copolymers at 180 °C, the molten PCL blocks are rejected from the front of PLLA crystal growth into the amorphous regions, which will lead to PCL and PLLA blocks exhibiting obvious fractionated crystallization and forming various morphologies depending on the length of PLLA segment. On the contrary, PCL blocks more easily form banded spherulites after PCL‐PLLA copolymers are annealed at 80 °C because the preexisting PLLA crystal template and the dangling amorphous PLLA chains on PCL segments more easily cause unequal stresses at opposite fold surfaces of PCL lamellae during the growth process. Also, it was found that the growth rate of banded spherulites is less than that of classical spherulites and the growth rate of banded spherulites decreases with decreasing band spacing. © 2019 Society of Chemical Industry
Quantitative Proteomic Analysis of Simian Primary Hepatocytes Reveals Candidate Molecular Markers for Permissiveness to Relapsing Malaria Plasmodium cynomolgi
Authors: Dembele Laurent , Gupta Devendra Kumar , Dutta Bamaprasad , Chua Adeline C. Y. , Sze Siu Kwan , Bifani Pablo
Published: August 2019

A major obstacle impeding malaria research is the lack of an in vitro system capable of supporting infection through the entire liver stage cycle of the parasite, including that of the dormant forms known as hypnozoites. Primary hepatocytes lose their liver specific functions in long‐term in vitro culture. The malaria parasite Plasmodium initiates infection in hepatocyte. This corresponds to the first step of clinically silent infection and development of malaria parasite Plasmodium in the liver. Thus, the liver stage is an ideal target for development of novel antimalarial interventions and vaccines. However, drug discovery against Plasmodium liver stage is severely hampered by the poor understanding of host–parasite interactions during the liver stage infection and development. In this study, tandem mass tag labeling based quantitative proteomic analysis is performed in simian primary hepatocytes cultured in three different systems of susceptibility to Plasmodium infection. The results display potential candidate molecular markers, including asialoglycoprotein receptor, apolipoproteins, squalene synthase, and scavenger receptor B1 (SR‐BI) that facilitate productive infection and full development in relapsing Plasmodium species. The identification of these candidate proteins required for constructive infection and development of hepatic malaria liver stages paves the way to explore them as therapeutic targets.
Template‐based modeling by ClusPro in CASP13 and the potential for using co‐evolutionary information in docking
Authors: Porter Kathryn A. , Padhorny Dzmitry , Desta Israel , Ignatov Mikhail , Beglov Dmitri , Kotelnikov Sergei , Sun Zhuyezi , Alekseenko Andrey , Anishchenko Ivan , Cong Qian , Ovchinnikov Sergey , Baker David , Vajda Sandor , Kozakov Dima
Published: August 2019

As a participant in the joint CASP13‐CAPRI46 assessment, the ClusPro server debuted its new template‐based modeling functionality. The addition of this feature, called ClusPro TBM, was motivated by the previous CASP‐CAPRI assessments and by the proven ability of template‐based methods to produce higher‐quality models, provided templates are available. In prior assessments, ClusPro submissions consisted of models that were produced via free docking of pre‐generated homology models. This method was successful in terms of the number of acceptable predictions across targets; however, analysis of results showed that purely template‐based methods produced a substantially higher number of medium‐quality models for targets for which there were good templates available. The addition of template‐based modeling has expanded ClusPro's ability to produce higher accuracy predictions, primarily for homomeric but also for some heteromeric targets. Here we review the newest additions to the ClusPro web server and discuss examples of CASP‐CAPRI targets that continue to drive further development. We also describe ongoing work not yet implemented in the server. This includes the development of methods to improve template‐based models and the use of co‐evolutionary information for data‐assisted free docking.
A strategy of rapidly screening out herbicidal chemicals from Eucalyptus essential oils
Authors: Li Aoxin , Wu Hanwen , Feng Yuanjiao , Deng Siyu , Hou Aijiao , Che Fenfang , Liu Yuanyuan , Geng Qianqian , Ni Hanwen , Wei Yun
Published: August 2019

BACKGROUND

To enhance discovering efficiency of new herbicidal compounds, a strategy for rapidly screening out strongly herbicidal chemical components from natural resources is necessary.

RESULTS

Seventeen essential oils selected from 14 Eucalyptus species and hybrids were evaluated for their herbicidal activities on annual ryegrass. A feasible strategy was established for rapidly pinpointing the chemicals contributing to strong herbicidal activities without the process of isolation and purification of individual compounds. This strategy was based on gas chromatography–mass spectrometry (GC–MS) coupled with principal component analysis (PCA) and verified by the bioassay results using several individual compounds. Two strong herbicidal compounds trans‐pinocarveol and α‐terpineol were screened out using the strategy. The strong herbicidal activity of trans‐pinocarveol was discovered for the first time.

CONCLUSION

The established strategy of screening herbicidal compounds from natural resources is simple, feasible and reliable. © 2019 Society of Chemical Industry
Solar Energy Harvesting Using Pyroelectric Effect Associated with Piezoelectric Buzzer
Authors: Azad Puneet , Khushboo  , Vaish Rahul
Published: August 2019

It is now well reported that the coatings of graphene/candle soot/black carbon can improve the performance of pyroelectric materials. Herein, the performance of candle soot‐coated pyroelectric material (piezoelectric buzzer) under solar heating is reported. To compare the performance, coated/uncoated piezoelectric buzzers are exposed to solar light as well as IR lamp separately. Piezoelectric buzzer shows multiple times superior performance after coating of candle soot. The open‐circuit voltage improves five times with a peak voltage of 3.31 V in solar light. The comparative enhancement in short‐circuit pyroelectric current is four times with a peak current of 2.73 μA. Also, the power and energy densities show multifold enhancement after coating.
Formation Mechanism of Large Inclusions in 80t 20Cr–8Ni Stainless Steel Casting for Nuclear Power
Authors: Wang Qiming , Cheng Guoguang , Li Jingyu , Dou Wenzhe , Hu Xuewen
Published: August 2019

80t 20Cr–8Ni stainless steel castings are used to manufacture pump casing for nuclear power. However, large inclusions are usually observed on an ingot surface, which cause failure in penetrant testing. To clarify the formation mechanism of large inclusions, the evolution, growth, and aggregation of inclusions during the argon oxygen decarburization furnace (AOD) refining–Ca treatment–ingot casting process are investigated. The results show that Al2O3 clusters >50 μm and single Al2O3 particles >10 μm are typical large inclusions on ingot surface. After aluminum addition in AOD, typical inclusions are spinel or dual‐phase CaO–MgO–Al2O3. After Ca treatment, typical inclusions are liquid or dual‐phase CaO–MgO–Al2O3. With temperature decreasing during casting process, the mass fraction of Al2O3 keeps on increasing due to decreasing oxygen and aluminum solubility. It is concluded that Al2O3 is formed during casting process. Single Al2O3 particles grow up to ≥7.5 μm or more. With the size of single Al2O3 particles increasing, Al2O3 clusters are formed mainly through Stokes and turbulent collision. In addition, the aggregation area of single Al2O3 particles and Al2O3 clusters is formed on the surface of ingot.
A Strong Scalar Weak Gravity Conjecture and some implications
Authors: Gonzalo Eduardo , Ibáñez Luis E.
Published: August 2019

Abstract

We propose a new version of the scalar Weak Gravity Conjecture (WGC) which would apply to any scalar field coupled to quantum gravity. For a single scalar it is given by the differential constraint (V″)2 ≤ (2V‴2 − V″V′′′′)

$$ {M}_{\mathrm{p}}^2 $$

M
p
2

, where V is the scalar potential. It corresponds to the statement that self-interactions of a scalar must be stronger than gravity for any value of the scalar field. We find that the solutions which saturate the bound correspond to towers of extremal states with mass

$$ {m}^2\left(\phi \right)={m}_0^2/\left({\left(R/m\right)}^2+1/{(nR)}^2\right) $$

m
2

ϕ

=

m
0
2

/

R
/
m

2

+
1
/

nR

2

, with R
2 = e

ϕ
, consistent with the emergence of an extra dimension at large or small R and the existence of extended objects (strings). These states act as WGC states for the scalar ϕ. It is also consistent with the distance swampland conjecture with a built-in duality symmetry. All of this is remarkable since neither extra dimensions nor string theory are put in the theory from the beginning, but they emerge. This is quite analogous to how the 11-th dimension appears in M-theory from towers of Type IIA solitonic D0-branes. From this constraint one can derive several swampland conjectures from a single principle. In particular one finds that an axion potential is only consistent if f ≤ M
p, recovering a result already conjectured from other arguments. The conjecture has far reaching consequences and applies to several interesting physical systems: i) Among chaotic inflation potentials only those asymptotically linear may survive. ii) If applied to the radion of the circle compactification of the Standard Model to 3D with Dirac neutrinos, the constraint implies that the 4D cosmological constant scale must be larger than the mass of the lightest neutrino, which must be in normal hierarchy. It also puts a constraint on the EW scale, potentially explaining the hierarchy problem. This recovers and improves results already obtained by applying the AdS swampland conjecture, but in a way which is independent from UV physics. iii) It also constraints simplest moduli fixing string models. The simplest KKLT model is compatible with the constraints but the latter may be relevant for some choices of parameters.
The asymptotic growth of states of the 4d $$ \mathcal{N}=1 $$ superconformal index
Authors: Cabo-Bizet Alejandro , Cassani Davide , Martelli Dario , Murthy Sameer
Published: August 2019

Abstract

We show that the superconformal index of

$$ \mathcal{N}=1 $$

N
=
1

superconformal field theories in four dimensions has an asymptotic growth of states which is exponential in the charges. Our analysis holds in a Cardy-like limit of large charges, for which the index is dominated by small values of chemical potentials. In this limit we find the saddle points of the integral that defines the superconformal index using two different methods. One method, valid for finite N, is to first take the Cardy-like limit and then find the saddle points. The other method is to analyze the saddle points at large N and then take the Cardy-like limit. The result of both analyses is that the asymptotic growth of states of the superconformal index exactly agrees with the Bekenstein-Hawking entropy of supersymmetric black holes in the dual AdS5 theory.
A comparative study of dynamic adsorption of anionic synthetic and nanocellulose-based surfactant in Malaysian reservoir
Authors: Ayoub Muhammad , Mohyaldinn Mysara Eissa , Mahmood Syed Mohammad , Aqsha Aqsha , Jufar Shiferaw Regassa , Farrukh Sarah , Inayat Farrukh , Shamsuddin Muhammad Rashid
Published: August 2019

This project is aimed at studying the applicability of nanocellulose-based surfactant as a sustainable surfactant for enhanced oil recovery process (EOR) in Malaysia. Abundant biomass waste from palm oil industry in Malaysia is hard to be disposed of. Therefore, potential application of biomass in chemical EOR is an attractive alternative to minimize these problems. For this study, nanocellulose is synthesized from oil palm empty fruit bunch (OPEFB) and undergoes chemical modification for it to act like a surfactant. All methods and techniques in synthesizing nanocellulose and preparing nanocellulose-based surfactant are made inhouse. While waiting for the material preparation, adsorption study is carried out by using anionic synthetic surfactant. Characterization result shows the nanocellulose undergoes chemical modification successfully. The IFT results for the nanocellulose-based surfactants are also in a good and acceptable range, but there are some limitations in using nanocellulose-synthesized surfactant. The average particle size of nanocellulose is 283.5 µm which is larger than size of the reservoir pore throat. Dynamic adsorption cannot be performed as the large particle size of nanocellulose might plug the porous domains. Therefore, it is recommended to further improve the method of synthesizing nanocellulose from OPEFB because the nanocellulose-based surfactant is expected to have potential of lower adsorption in porous media once it becomes nanosized and due to its advantages such as being of lower cost and environmental friendly compared to other commercial surfactants.
Experimental investigation of bio-enhancer drilling fluid additive: Can palm tree leaves be utilized as a supportive eco-friendly additive in water-based drilling fluid system?
Authors: Al-Hameedi Abo Taleb T. , Alkinani Husam H. , Dunn-Norman Shari , Al-Alwani Mustafa A. , Al-Bazzaz Waleed H. , Alshammari Abdullah F. , Albazzaz Hussien W. , Mutar Rusul A.
Published: August 2019

Serious problems will be presented due to using conventional chemical additives to regulate the drilling mud properties, as they have health, safety, and environmental side effects. Thus, there is a considerable necessity for alternative multifunctional bio-enhancer drilling mud additives, which can assist in optimizing the drilling fluid specifications and enhance its effectiveness with the least effects on the environment and the drilling personnel safety. The effects of adding two concentrations of palm tree leaves powder (PTLP) to water-based mud were conducted under fresh and aged conditions using standard API drilling fluids testing methods such as rheometer/viscometer, pH meter and temperature, and filter press. All tests results were minutely recorded to understand the influence of PTLP additives on the drilling mud properties. The results indicated that PTLP as an effective material to be used as pH reducer, viscosity reducer, and as an excellent filtration loss control agent under the surface and sub-surface conditions. Thus, PTLP has excellent feasibility to be utilized as biodegradable drilling mud additive replacing or at least supporting other conventional chemical additives, which have usually been used for the same purposes such as lignosulphonate, chrome-lignite, and Resinex. Finally, this work can serve as a practical guide for minimizing the cost of the drilling fluid and reducing the amount of non-biodegradable waste disposed to the environment.
East‐West Differential Underthrusting of the Indian Lithospheric Plate Beneath Central Tibet Revealed by Imaging VP/VS
Authors: Si Shaokun , Gao Rui , Tian Xiaobo
Published: August 2019

Although numerous research studies have already provided basic information on deeper lithospheric structure under Tibet, the northernmost edge and the geometry of the northward underthrusting of the Indian mantle lithosphere are yet to be understood. The P wave to S wave velocity ratio (VP/VS) can provide more insight into the mantle physical state than either VP or VS alone, owing to their different sensitivities to partial melting, temperature, and composition. High VP/VS usually indicates that partial melting exists in the upper mantle, while anomalously low VP/VS in the upper mantle reflects the enrichment of orthopyroxene in the subduction zone mantle wedge. Using teleseismic records of 164 broadband stations deployed in central Tibet, we obtained a high‐resolution velocity ratio image of the upper mantle. A striking difference is seen between western and eastern Tibet. A distinct high VP/VS zone exists at relatively a shallow depth (<200 km) to the west of the Yadong‐Gulu Rift, while the eastern part exhibits a shallow region (south of the Bangong‐Nujiang suture in the depth range of 120–160 km) with abnormally low VP/VS. Moreover, there are high VP/VS areas existing below 270‐km depth, and it appears further east at depth of 340 km than that at depth of 270 km. We propose that this difference reflects different geometries of the underthrusting Indian mantle lithosphere from west to east. Slab tearing under eastern Tibet and lithospheric delamination under western Tibet are likely good candidates to explain the observation.
Assessing the Role of High‐Frequency Winds and Sea Ice Loss on Arctic Phytoplankton Blooms in an Ice‐Ocean‐Biogeochemical Model
Authors: Castro de la Guardia L. , Garcia‐Quintana Y. , Claret M. , Hu X. , Galbraith E. D. , Myers P. G.
Published: August 2019

The long‐term trend of increasing phytoplankton net primary production (NPP) in the Arctic correlates with increasing light penetration due to sea ice loss. However, recent studies suggest that enhanced stormy wind mixing may also play a significant role enhancing NPP. Here, we isolate the role of sea ice and stormy winds (hereafter high‐frequency winds) using an eddy‐permitting ice‐ocean‐biogeochemical model configured for the North Atlantic and the Arctic. In the model, the presence of high‐frequency winds stimulates nutrient upwelling by producing an earlier and longer autumn‐winter mixing period with deeper mixing layer. The early onset of autumn mixing results in nutrients being brought‐up to near‐surface waters before the light becomes the dominant limiting factor, which leads to the autumn bloom. The enhanced mixing results in higher nutrient concentrations in spring and thus a large spring bloom. The model also shows significant iron limitation in the Labrador Sea, which is intensified by high‐frequency winds. The effect of sea ice loss on NPP was found to be regionally dependent on the presence of high‐frequency winds. This numerical study suggests high‐frequency winds play significant role increasing NPP in the Arctic and sub‐Arctic by alleviating phytoplankton nutrient limitation and that the isolated effect of sea ice loss on light plays a comparatively minor role.
Innovations in (U–Th)/He, Fission Track, and Trapped Charge Thermochronometry with Applications to Earthquakes, Weathering, Surface‐Mantle Connections, and the Growth and Decay of Mountains
Authors: Ault Alexis K. , Gautheron Cécile , King Georgina E.
Published: August 2019

A transformative advance in Earth science is the development of low‐temperature thermochronometry to date Earth surface processes or quantify the thermal evolution of rocks through time.Grand challengesand new directions in low‐temperature thermochronometry involve pushing the boundaries of these techniques to decipher thermal histories operative over seconds to hundreds of millions of years, in recent or deep geologic time and from the perspective of atoms to mountain belts. Here we highlight innovation in bedrock and detrital fission track, (U–Th)/He, and trapped charge thermochronometry, as well as thermal history modeling that enable fresh perspectives on Earth science problems. These developments connect low‐temperature thermochronometry tools with new users across Earth science disciplines to enable transdisciplinary research. Method advances include radiation damage and crystal chemistry influences on fission track and (U–Th)/He systematics, atomistic calculations of He diffusion, measurement protocols and numerical modeling routines in trapped charge systematics, development of4He/3He and new (U–Th)/He thermochronometers, and multimethod approaches. New applications leverage method developments and include quantifying landscape evolution at variable temporal scales, changes to Earth's surface in deep geologic time and connections to mantle processes, the spectrum of fault processes from paleoearthquakes to slow slip and fluid flow, and paleoclimate and past critical zone evolution. These research avenues have societal implications for modern climate change, groundwater flow paths, mineral resource and petroleum systems science, and earthquake hazards.
Multicore Parallel Tempering Bayeslands for Basin and Landscape Evolution
Authors: Chandra Rohitash , Müller R. Dietmar , Azam Danial , Deo Ratneel , Butterworth Nathaniel , Salles Tristan , Cripps Sally
Published: August 2019

The Bayesian paradigm is becoming an increasingly popular framework for estimation and uncertainty quantification of unknown parameters in geophysical inversion problems. Badlands is a landscape evolution model for simulating topography evolution at a broad range of spatial and temporal scales. Our previous work presented Bayeslands that used the Bayesian inference for estimating unknown parameters in the Badlands model using Markov chain Monte Carlo sampling. Bayeslands faced challenges in terms of computational issues and convergence due to multimodal posterior distributions. Parallel tempering is an advanced Markov chain Monte Carlo method suited for irregular and multimodal posterior distributions. In this paper, we extend Bayeslands using parallel tempering with high‐performance computing to address previous limitations in Bayeslands. Our results show that parallel tempering Bayeslands not only reduces the computation time‚ but also provides an improvement in sampling multimodal posterior distributions, which motivates future application to continental scale landscape evolution models.
Global Alfvén Wave Power in the Auroral Zone in Relation to the AE Index
Authors: Keiling Andreas , Thaller Scott , Wygant John , Dombeck John
Published: August 2019

The importance of Alfvén waves in energy transport inside the magnetosphere has been demonstrated over the last two decades. Generated in various magnetospheric regions, much of their energy carried to the auroral zone is deposited inside the auroral acceleration region (AAR) via particle acceleration. In this report, we present the integrated contributions of Alfvén wave power to the nightside auroral zone during different levels of auroral activity, as measured by the auroral electrojet (AE) index. Data were collected from an ideal vantage point, namely, above the nominal AAR, over a 6‐year period of Polar satellite operation. We provide functional forms for the total inflowing and outflowing Alfvén wave powers, both of which are linear—at least up to an AE index of 700 nT. For all AE values the power inflow is significantly larger than the power outflow; therefore, the estimated net wave power flowing into the AAR is sufficient to account for the integrated precipitating Alfvénic electron power in the nightside auroral zone below the AAR. The estimated global Alfvén wave absorption (by electrons) and reflection are, respectively, 56% and 33% (upper limit), while an excess wave power of 11% (lower limit) is available for other energy conversion processes, such as Joule heating and Alfvénic ion outflow.
Late Oligocene to Pliocene Extension in the Maltese Islands and Implications for Geodynamics of the Pantelleria Rift and Pelagian Platform
Authors: Martinelli Mattia , Bistacchi Andrea , Balsamo Fabrizio , Meda Marco
Published: August 2019

The tectonic and geodynamic evolution of the Pelagian platform and of the Pantelleria Rift System, located in the foreland of the Apennine‐Sicilian‐Maghrebian Belt, from the Late Oligocene onward, is still debated. Here we present a new interpretation based on structural data collected in the Malta and Gozo islands. With a tectonic back‐stripping approach, we recognized two main extensional events separated by a period of tectonic quiescence: (D1) Early Miocene WNW‐ESE extension and (D2) Late Miocene to Pliocene N‐S extension that led to the opening of the Pantelleria Rift System. During both extensional events the Maltese Islands and the Pelagian Platform were located in the foreland of the Apennine‐Sicilian‐Maghrebian Belt (Western Mediterranean Arc), in a period of slab rollback. We suggest that both tectonic events are an evidence of the extensional regime imposed on the foreland area by the rollback of the subducting slab. The switch in the main extension axis between D1 and D2 (WNW‐ESE vs. N‐S) can be interpreted as a result of the varying orientation and distance of the trench due to the progressive development of the Western Mediterranean Arc and provides an independent tool to “monitor” the slab rollback. Results obtained in this study allowed, for the first time, to bind the tectonic evolution of the area with the geodynamic evolution of the Western and Central Mediterranean.
Canopy Adjustment and Improved Cloud Detection for Remotely Sensed Snow Cover Mapping
Authors: Rittger Karl , Raleigh Mark S. , Dozier Jeff , Hill Alice F. , Lutz James A. , Painter Thomas H.
Published: August 2019

Maps of snow cover serve as early indicators for hydrologic forecasts and as inputs to hydrologic models that inform water management strategies. Advances in snow cover mapping have led to increasing accuracy, but unsatisfactory treatment of vegetation's interference when mapping snow has led to maps that have limited utility for water forecasting. Vegetation affects snow mapping because ground surfaces not visible to the satellite produce uncertainty as to whether the ground is snow covered. At nadir, the forest canopy obscures the satellite view below the canopy. At oblique viewing angles, the forest floor is obscured by both the canopy and the projection of tree profiles onto the forest floor. We present a canopy correction method based on Moderate Resolution Imaging Spectroradiometer satellite imagery validated with field observations that mitigates geometric and georegistration issues associated with changing satellite acquisition angles in forested areas. The largest effect from a variable viewing zenith angle on the viewable gap fraction in forested areas occurs in moderately forested areas with 30–40% tree canopy coverage. Cloud cover frequently causes errors in snow identification, with some clouds identified as snow and some snow identified as cloud. A snow‐cloud identification method utilizes a time series of fractional vegetation and rock land‐surface data to flag snow‐cloud identification errors and improve snow‐map accuracy reducing bias by 20% over previous methods. Together, these contributions to snow‐mapping techniques could advance hydrologic forecasting in forested, snow‐dominated basins that comprise an estimated one fifth of Northern Hemisphere snow‐covered areas.
Characterizing Biases in Mountain Snow Accumulation From Global Data Sets
Authors: Wrzesien Melissa L. , Pavelsky Tamlin M. , Durand Michael T. , Dozier Jeff , Lundquist Jessica D.
Published: August 2019

Mountain snow has a fundamental role in regional water budgets through its seasonal accumulation, storage, and melt. However, characterizing snow accumulation over large regions remains difficult because of limited observational networks and the inability of available satellite instruments to remotely sense snow depth or water equivalent in mountains. Models offer some ability to estimate snow water storage (SWS) on mountain range to continental scales. Here we compare four commonly used global data sets to understand whether there is a consensus regarding mountain SWS estimates among them. The data sets—European Centre for Medium‐Range Weather Forecasts Reanalysis‐Interim, Global Land Data Assimilation System, Modern‐Era Retrospective Analysis for Research and Applications version 2, and Variable Infiltration Capacity—agree to within ±36% of the four–data set average for total global SWS. When mountain areas are extracted using a new seasonal mountain snow classification data set, the four data products have more agreement, where all are within ±21% of the seasonal SWS for mountain regions. However, when compared to high‐resolution (9 km) simulations of SWS from the Weather Research and Forecasting (WRF) regional model, the four global products differ from WRF‐estimated North American mountain snow accumulation by 40–66%, with a negative bias up to 651 km3, comparable to the annual streamflow of the Mississippi River. If we extend the North America SWS bias to global mountains, the global data sets may miss as much as 1,500 km3 of SWS, equivalent to 4% of the flow in all the world's rivers. The potential difference of SWS suggests more work must be done to characterize water resources in snow‐dominated regions, particularly in mountains.
Comparing Discharge Estimates Made via the BAM Algorithm in High‐Order Arctic Rivers Derived Solely From Optical CubeSat, Landsat, and Sentinel‐2 Data
Authors: Feng Dongmei , Gleason Colin J. , Yang Xiao , Pavelsky Tamlin M.
Published: August 2019

Conventional satellite platforms are limited in their ability to monitor rivers at fine spatial and temporal scales: suffering from unavoidable trade‐offs between spatial and temporal resolutions. CubeSat constellations, however, can provide global data at high spatial and temporal resolutions, albeit with reduced spectral information. This study provides a first assessment of using CubeSat data for river discharge estimation in both gauged and ungauged settings. Discharge was estimated for 11 Arctic rivers with sizes ranging from 16 to >1,000 m wide using the Bayesian at‐many‐stations hydraulic geometry‐Manning algorithm (BAM). BAM‐at‐many‐stations hydraulic geometry solves for hydraulic geometry parameters to estimate flow and requires only river widths as input. Widths were retrieved from Landsat 8 and Sentinel‐2 data sets and a CubeSat (the Planet company) data set, as well as their fusions. Results show satellite data fusion improves discharge estimation for both large (>100 m wide) and medium (40–100 m wide) rivers by increasing the number of days with a discharge estimation by a factor of 2–6 without reducing accuracy. Narrow rivers (<40 m wide) are too small for Landsat and Sentinel‐2 data sets, and their discharge is also not well estimated using CubeSat data alone, likely because the four‐band sensor cannot resolve water surfaces accurately enough. BAM technique outperforms space‐based rating curves when gauge data are available, and its accuracy is acceptable when no gauge data are present (instead relying on global reanalysis for discharge priors). Ultimately, we conclude that the data fusion presented here is a viable approach toward improving discharge estimates in the Arctic, even in ungauged basins.
Bi‐ISAR sparse imaging algorithm with complex Gaussian scale mixture prior
Authors: Zhu Xiaoxiu , Shi Lin , Guo Baofeng , Hu Wenhua , Shang Chaoxuan , Han Ning
Published: August 2019

The performance of both autofocusing and imaging resolution degrades using the traditional autofocusing and range–Doppler algorithm for bistatic inverse synthetic aperture radar (Bi‐ISAR) with sparse apertures. A Bi‐ISAR sparse imaging algorithm based on complex Gaussian scale mixture (CGSM) prior is proposed to jointly achieve the high‐resolution imaging and autofocusing. First, a sparse basis matrix with the time‐varying bistatic angle is constructed to represent the sparse echo data and the Bi‐ISAR joint with autofocusing imaging model is established based on compressed sensing from sparse apertures. Second, the elements of the target image and the noise are assumed to be a CGSM prior with Gaussian distribution, respectively. Finally, the sparse image reconstruction and phase autofocusing are accomplished by the variational Bayesian expectation maximisation method. The proposed algorithm with the full Bayesian inference can obtain a well‐focused image without manual adjustments of regularisation parameters. Meanwhile, it can avoid the local minimum and structural errors, due to utilising the statistical information of a posterior. Simulated results of electromagnetic numerical data verify the superiority of the algorithm in autofocusing, sparse imaging and noise suppression performance.
Scaling down of cobalt quantum‐dots by colloidal route for non‐volatile memory device application
Authors: Yadav Manoj , Velampati Ravi Shankar R. , Mandal Debaprasad
Published: August 2019

The present work details the synthesis of cobalt quantum‐dots (Co QDs) with size downscaling to 1–2 nm and their applications in non‐volatile memory (NVM) devices. The process of colloidal synthesis is simple and provides the control over a wide range of QDs size. The scaled‐down colloidal Co QDs are applied for the NVM device fabrication. Colloidal synthesised Co QDs are spin‐coated over silicon dioxide wafer for the fabrication of floating‐gate NVM devices. Capacitance–voltage (C –V) and capacitance–time (C –t) measurements of the fabricated NVM device indicate a low voltage operation of device. A sweep voltages as small as 1.2–4 V lead to a flat band voltage shift of 0.35–1.5 V, evidencing the low operating voltage and low power NVM applications. Further, retention characteristics show a robust retention by fabricated NVM device. In addition, C –V measurements are done for the several samples in order to study the process repeatability. The work also is compared with the other processes for the floating gate memory device.
Recovery from Strenuous Downhill Running in Young and Older Physically Active Adults
Authors: Hayashi Koichiro , Leary Miriam E. , Roy Stephen J. , Laosiripisan Jitanan , Pasha Evan P. , Tanaka Hirofumi
Published: August 2019

There is a well-conceived notion that rate of recovery from strenuous exercise gets slower with age. However, it is unclear whether older adults who exercise habitually demonstrate slower rates of recovery. We determined whether older adults who are physically active demonstrate slower rates of recovery from unaccustomed strenuous exercise compared with younger peers. Healthy young sedentary (n=10, 28±2 years), young endurance-trained (n=15, 27±2 years), and older endurance-trained (n=14, 58±2 years) men and women were studied. Participants performed 45 min of downhill running at 65% of their maximal oxygen consumption. Visual analog pain scores of muscle groups increased at 24, 48, and 72 h in all three groups (p<0.05), and changes in the muscular pain scale of the legs was smaller in the older trained group than in the young trained group. Maximum isometric strengths at 90° decreased in all groups at 24 h, but the recovery rates were not different at 72 h among the groups. Plasma creatine kinase activity and myoglobin concentration increased at 24 h following downhill running and returned to baseline at 48 h in both the young and older trained groups. The present findings are not consistent with the prevailing notion that older trained adults have a slower rate of recovery from strenuous exercise.
Pacing characteristics of whole and part‐game players in professional rugby union
Authors: Tee Jason C. , Coopoo Yoga , Lambert Mike
Published: August 2019

Contemporary theories on players’ intensity distribution in team sports suggest that they regulate their outputs using pacing strategies. There is currently limited information on how movement patterns and pacing strategies of rugby union players in different position groups (forwards and backs) vary when exposed to different bout types (whole game, starter or finisher). Global positioning system (GPS) and accelerometer data were collected from 100 professional match participations to determine temporal effects on movement patterns. For forwards, finishers (players who entered the game as substitutes) demonstrated significantly greater high‐speed running distance (% difference, ± 90%CI; magnitude‐based inference and effect size) (↑ 55, ±17%; very likely large) and acceleration frequency (↑ 78, ±59%; very likely large) than whole game players. For backs, starters (players who started the game and were later substituted) displayed greater high‐speed running distance than whole game players (↑ 27, ±21%; ES = likely medium) but this difference did not achieve statistical significance (p = .07). Forwards displayed “slow‐positive” pacing strategies regardless of bout type, while backs displayed “flat” pacing strategies. Forwards and backs adopt different pacing strategies regardless of bout type, with forwards demonstrating progressively greater performance decrements over the course of the match. These findings reflect differing physical demands, notably contact and running loads, of players in different positions.
Climate change and future power systems: the importance of energy storage in reduced-hydropower systems in the American Southwest
Authors: Wadsack Karin , Acker Thomas L
Published: August 2019

Power systems are responding to climate change both through efforts to reduce greenhouse-gas emissions and through adaptive responses to the effects of climate change, such as changes in hydroelectric generation. These changes, experienced together, may cause new patterns in plant operations or pollutant emissions. Various scenarios representing future climate change mitigation and adaptation in the power sector were explored using the PLEXOS production-cost model, with a focus on plant utilization and behaviour, total system-operating costs and total CO2 emissions. Further, the effect of introducing widespread utility-scale energy storage into these scenarios was quantified in terms of these same parameters. Large increases in variable renewable penetration combined with extreme reduction of hydroelectric generation in the American Southwest (based on climate modelling in the Colorado River basin and actual drought experience in California) caused significant increases in thermal plant start-up/shutdown cycling. The introduction of storage significantly reduced this cycling, without a material increase in CO2 emissions. Storage introduced on even a modest scale can provide considerable flexibility under a range of future power-system circumstances that might be experienced due to climate change.