bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of Intraseasonal East Asian Winter Cold Temperature Anomalies in Positive and Negative Phases of the Arctic Oscillation
Authors: Song Lei , Wu Renguang 
Published: August 2018

AbstractThis study investigates the relationship between intraseasonal variations of the Arctic Oscillation (AO) and East Asian winter temperature. Based on the lead‐lag correlation between 30‐ and 60‐day band‐pass filtered daily AO index and regional mean surface temperature anomalies over eastern China, it is found that the cold temperature anomalies occur following both positive and negative AO phases with nearly the same probability. Composite analysis reveals prominent differences in surface temperature and tropospheric circulation anomalies between the two types of years. During the years when negative AO leads cold anomalies over East Asia, the AO‐related pressure anomalies extend to Eurasia, inducing an enhanced Siberian high with a large spatial coverage in midlatitude and high latitude; the midtropospheric wave train along the polar front jet takes an eastward path and induces the deepening of the East Asian trough; the resultant cold surface temperature anomalies affect a large region over East Asia. During the years when positive AO leads cold anomalies, the AO‐related pressure anomalies extend to North America and the high pressure anomalies over East Asia are located at midlatitudes with a relatively small spatial coverage; the midtropospheric wave train along the polar front jet takes a southward path over Asia, inducing the development of a trough over subtropical Asia with a supplementary contribution from a subtropical wave train; the resultant cold surface temperature anomalies influence inland East Asia with a relatively small extent. There appears to be a notable difference in the relationship between the stratospheric and tropospheric change between the two types of years.
B Vitamins and Their Congeners as Potential Drivers of Microbial Community Composition in an Oligotrophic Marine Ecosystem
Authors: Suffridge C. P. , Gómez‐Consarnau L. , Monteverde D. R. , Cutter L. , Arístegui J. , Alvarez‐Salgado X. A. , Gasol J. M. , Sañudo‐Wilhelmy S. A. 
Published: August 2018

AbstractDetermining the factors that influence marine microbial growth and community structure are critical for the understanding of global carbon cycling. Since the early twentieth century, it has been known that B vitamins play an important role in phytoplankton community dynamics. Limited oceanic dissolved B vitamin distributions indicate that these important coenzymes are present at picomolar levels, which could be too low to support maximal phytoplankton growth, and vast regions of the ocean exist where they are undetectable. Despite their importance, particulate B vitamin concentrations of field microbial populations are unknown. Here we report B vitamin concentrations measured in both the particulate and dissolved fractions, including multiple biochemically relevant B vitamin congeners. We establish their spatial distributions spanning distinct biogeographic and oceanographic regimes in the Mediterranean Sea and the Eastern Atlantic Ocean and show that all congeners are present both dissolved in seawater and in suspended particles. We observe that B vitamins cooccur in patches defined by regional biogeographic and oceanographic features. Additionally, distinct patterns of congener relative abundance in the dissolved and particulate pools provide insight to biological and chemical cycling of these compounds between and within the dissolved and particulate pools. Finally, linear model results demonstrate that model fits of microbial assemblages are strongest when they include both inorganic nutrients and dissolved B vitamin concentrations. We believe that these findings represent an advance in our understanding of B vitamin oceanographic distributions and point to interesting hypotheses of their influence on marine microbial ecology.
Characteristics and Discharge Processes of M Events With Large Current in Triggered Lightning
Authors: Zhang Yang , Zhang Yi Jun , Zheng Dong , Lu Weitao 
Published: August 2018

AbstractObservations have been obtained of M events during triggered lightning flashes with a broadband very high frequency interferometer and measurements of electric field changes, channel‐base current, and high‐speed video. The current characteristics of 239 M events in 18 triggered lightning flashes are analyzed, and the discharge processes leading to large M currents are investigated. Sixty‐eight of the M events (28%) had peak currents exceeding 1 kA. The geometric average values of peak current, duration, 10–90% rise time, half peak width, charge transfer, interval from return stroke to M and background current are 2.358 kA, 0.627 ms,0.078 ms, 0.165 ms, 0.417 C, 2.172 ms, and 579 A, respectively. Compared to other M events, the M events with large peak current occurred closer in time to the preceding return stroke, and their corresponding current changes were more rapid. Three cases associated with the initiation processes of M events reveal that some large M events were initiated by fast positive streamers propagating away at a velocity of about 107 m/s followed by a possible recoil event, or by a dart leader while the channel of continuing current generated by previous leader still existed. It is found that a fast current pulse with 10–90% rise time of less than 300 μs is a necessary, but not sufficient, condition for the occurrence of large M events. The fast current pulse often corresponded to a low/close junction site.
Evapotranspiration Trends (1979–2015) in the Central Valley of California, USA: Contrasting Tendencies During 1981–2007
Authors: Szilagyi Jozsef , Jozsa Janos 
Published: August 2018

AbstractTrends in monthly evapotranspiration (ET) rates across three watersheds covering the Central Valley in California were calculated by the latest calibration‐free version of the complementary relationship of evaporation for 1979–2015. While a recent study concluded that ET rates of the irrigated fields in the Central Valley were declining in 1981–2007, here an ET trend of about 2.6 ± 12 mm per decade was found over the same period in spite of a drop in precipitation (−22 ± 30 mm per decade) and ET rates (−9.5 ± 10 mm per decade) for the rest of the watersheds, none of them statistically significant. After 2007, the precipitation decline accelerated causing a sharp drop in both irrigated and nonirrigated ET rates across the watersheds. Observations from the California Irrigation Management Information System support the present findings: Under increasing air temperatures, both dew point temperature and relative humidity values increased (at a statistically significant rate) during 1983–2007, while they reversed afterwards, in agreement with the estimated sharp irrigation ET trend decline for the remainder of the study period. Actual (in this case over irrigated fields) and reference ET rates complement each other, that is, they express opposite tendencies, as was demonstrated with California Irrigation Management Information System data, yielding a statistically significant plot‐scale irrigation ET rate increase of 31 to 41 (±17) millimeters per decade for 1983–2007 in accordance with a similar drop in reference ET rates of −28 to −50 (±16) millimeters per decade, depending on whether published monthly or daily values (aggregated to monthly ones after leaving out spurious measurements) were employed.
A Structure Function Model Recovers the Many Formulations for Air‐Water Gas Transfer Velocity
Authors: Katul Gabriel , Mammarella Ivan , Grönholm Tiia , Vesala Timo 
Published: August 2018

AbstractTwo ideas regarding the structure of turbulence near a clear air‐water interface are used to derive a waterside gas transfer velocity kL for sparingly and slightly soluble gases. The first is that kL is proportional to the turnover velocity described by the vertical velocity structure function Dww(r), where r is separation distance between two points. The second is that the scalar exchange between the air‐water interface and the waterside turbulence can be suitably described by a length scale proportional to the Batchelor scale lB=ηSc−1/2, where Sc is the molecular Schmidt number and η is the Kolmogorov microscale defining the smallest scale of turbulent eddies impacted by fluid viscosity. Using an approximate solution to the von Kármán‐Howarth equation predicting Dww(r) in the inertial and viscous regimes, prior formulations for kL are recovered including (i)
, vK is the Kolmogorov velocity defined by the Reynolds number vKη/ν = 1 and ν is the kinematic viscosity of water; (ii) surface divergence formulations; (iii)
, where u∗ is the waterside friction velocity; (iv)
for Keulegan numbers exceeding a threshold needed for long‐wave generation, where the proportionality constant varies with wave age, g is the gravitational acceleration; and (v)
in free convection, where qo is the surface heat flux and βo is the thermal expansion of water. The work demonstrates that the aforementioned kL formulations can be recovered from a single structure function model derived for locally homogeneous and isotropic turbulence.
Insights From Unsteady Flow Analysis of Underdamped Slug Tests in Fractured Rock
Authors: Quinn P. M. , Klammler H. , Cherry J. A. , Parker B. L. 
Published: August 2018

AbstractSlug tests generating oscillating (underdamped) responses are common in high‐transmissivity (T) zones, and the nature of the response depends on the plumbing of the test equipment and the formation properties. The standard approach for obtaining T is to measure pressure shallow in the riser pipe to obtain an accurate estimate of flow and then predict the formation response from this shallow measurement by accounting for friction and acceleration assuming steady flow conditions (parabolic radial velocity profile). In this study a mathematical solution is developed for unsteady oscillatory laminar flow that shows non‐parabolic radial velocity profiles resulting in larger frictional losses, which are out of phase with the average flow velocity, indicating that errors are introduced when using the standard approach for underdamped slug test analysis. The unsteady flow model produces correction factors that can be used to improve the standard approach for predicting the formation pressure; however, not all errors are eliminated. Consequently, a new procedure is presented and applied to underdamped slug tests observed in fractured rock that avoids errors associated with quantifying inertial and frictional effects along the test equipment. This is achieved through the use of two transducers, where one is placed shallow in the water column to infer flow, and one is placed inside the test interval to represent the formation pressure. Comparison of T estimated by the new procedure to T derived from constant head step tests show better agreement than T obtained when predicting the formation pressure from a shallow pressure measurement.
The Development of Wormholes in Laboratory‐Scale Fractures: Perspectives From Three‐Dimensional Simulations
Authors: Starchenko Vitaliy , Ladd Anthony J. C. 
Published: August 2018

AbstractWe investigate the development of wormholes in laboratory‐scale fractures using three‐dimensional numerical simulations. Well‐controlled initial conditions, involving a small perturbation near the inlet of an otherwise flat fracture aperture field, were used to make a systematic study of the effects of flow rate and reaction rate on the aperture evolution. We find at least two characteristic wormhole shapes, which can be grouped within a phase diagram in the space of Péclet and Damköhler numbers. We investigate how this phase diagram depends on fracture geometry, specifically the length (L) and width (W) in comparison to the initial aperture (h0). This information is used to determine an effective Damköhler number that leads to a Péclet and length‐independent phase boundary between wormholes and uniform dissolution. We relate these observations to experimental studies of wormhole formation in dissolving fractures.
Six Centuries of Upper Indus Basin Streamflow Variability and Its Climatic Drivers
Authors: Rao Mukund Palat , Cook Edward R. , Cook Benjamin I. , Palmer Jonathan G. , Uriarte Maria , Devineni Naresh , Lall Upmanu , D'Arrigo Rosanne D. , Woodhouse Connie A. , Ahmed Moinuddin , Zafar Muhammad Usama , Khan Nasrullah , Khan Adam , Wahab Muhammad 
Published: August 2018

AbstractOur understanding of the full range of natural variability in streamflow, including how modern flow compares to the past, is poorly understood for the Upper Indus Basin because of short instrumental gauge records. To help address this challenge, we use Hierarchical Bayesian Regression with partial pooling to develop six centuries long (1394–2008 CE) streamflow reconstructions at three Upper Indus Basin gauges (Doyian, Gilgit, and Kachora), concurrently demonstrating that Hierarchical Bayesian Regression can be used to reconstruct short records with interspersed missing data. At one gauge (Partab Bridge), with a longer instrumental record (47 years), we develop reconstructions using both Bayesian regression and the more conventionally used principal components regression. The reconstructions produced by principal components regression and Bayesian regression at Partab Bridge are nearly identical and yield comparable reconstruction skill statistics, highlighting that the resulting tree ring reconstruction of streamflow is not dependent on the choice of statistical method. Reconstructions at all four reconstructions indicate that flow levels in the 1990s were higher than mean flow for the past six centuries. While streamflow appears most sensitive to accumulated winter (January–March) precipitation and summer (May–September) temperature, with warm summers contributing to high flow through increased melt of snow and glaciers, shifts in winter precipitation and summer temperatures cannot explain the anomalously high flow during the 1990s. Regardless, the sensitivity of streamflow to summer temperatures suggests that projected warming may increase streamflow in coming decades, though long‐term water risk will additionally depend on changes in snowfall and glacial mass balance.
The Resazurin‐Resorufin System: Insights From a Decade of “Smart” Tracer Development for Hydrologic Applications
Authors: Knapp Julia L. A. , González‐Pinzón Ricardo , Haggerty Roy 
Published: August 2018

AbstractThe resazurin‐resorufin tracer system has been used to quantify surface water‐sediment interactions and microbial metabolic activity in stream ecosystems for one decade. This review describes the evolution of the tracer technique and summarizes how it has been used by the hydrologic and stream ecology communities. We highlight major hydrologic applications and milestones in the advancement of the reactive tracer system on scales ranging from cells to river reaches and catchments. We discuss the advantages and limitations of the resazurin‐resorufin system for hydrologic applications and suggest new directions of research, including how to address existing knowledge gaps. Beyond the goal of summarizing information that is specific to the development of the resazurin‐resorufin system, this review seeks to inform on the development of new “smart” tracer techniques as they, very likely, will face the same or similar challenges and opportunities encountered in the development of the resazurin‐resorufin system. The supporting information furthermore contains a detailed manual for the application of the resazurin‐resorufin system as hydrologic tracer and MATLAB codes for the analysis of their reactive transport.
Self-organization of active particles by quorum sensing rules
Authors: Bäuerle Tobias , Fischer Andreas , Speck Thomas , Bechinger Clemens 
Published: August 2018

AbstractMany microorganisms regulate their behaviour according to the density of neighbours. Such quorum sensing is important for the communication and organisation within bacterial populations. In contrast to living systems, where quorum sensing is determined by biochemical processes, the behaviour of synthetic active particles can be controlled by external fields. Accordingly they allow to investigate how variations of a density-dependent particle response affect their self-organisation. Here we experimentally and numerically demonstrate this concept using a suspension of light-activated active particles whose motility is individually controlled by an external feedback-loop, realised by a particle detection algorithm and a scanning laser system. Depending on how the particles’ motility varies with the density of neighbours, the system self-organises into aggregates with different size, density and shape. Since the individual particles’ response to their environment is almost freely programmable, this allows for detailed insights on how communication between motile particles affects their collective properties.
Bifidobacterium breve MRx0004 protects against airway inflammation in a severe asthma model by suppressing both neutrophil and eosinophil lung infiltration
Authors: Raftis Emma J. , Delday Margaret I. , Cowie Philip , McCluskey Seánín M. , Singh Mark D. , Ettorre Anna , Mulder Imke E. 
Published: August 2018

AbstractAsthma is a phenotypically heterogeneous disease. In severe asthma, airway inflammation can be predominantly eosinophilic, neutrophilic, or mixed. Only a limited number of drug candidates are in development to address this unmet clinical need. Live biotherapeutics derived from the gut microbiota are a promising new therapeutic area. MRx0004 is a commensal Bifidobacterium breve strain isolated from the microbiota of a healthy human. The strain was tested prophylactically and therapeutically by oral gavage in a house dust mite mouse model of severe asthma. A strong reduction of neutrophil and eosinophil infiltration was observed in lung bronchoalveolar lavage fluid following MRx0004 treatment. Peribronchiolar and perivascular immunopathology was also reduced. MRx0004 increased lung CD4+CD44+ cells and CD4+FoxP3+ cells and decreased activated CD11b+ dendritic cells. Cytokine analysis of lung tissue revealed reductions of pro-inflammatory cytokines and chemokines involved in neutrophil migration. In comparison, anti-IL-17 antibody treatment effectively reduced neutrophilic infiltration and increased CD4+FoxP3+ cells, but it induced lung eosinophilia and did not decrease histopathology scores. We have demonstrated that MRx0004, a microbiota-derived bacterial strain, can reduce both neutrophilic and eosinophilic infiltration in a mouse model of severe asthma. This novel therapeutic is a promising next-generation drug for management of severe asthma.
The impact of non-alcoholic fatty liver disease and metabolic syndrome on the progression of coronary artery calcification
Authors: Cho Yun Kyung , Kang Yu Mi , Yoo Jee Hee , Lee Jiwoo , Lee Seung Eun , Yang Dong Hyun , Kang Joon-Won , Park Joong-Yeol , Jung Chang Hee , Kim Hong-Kyu , Lee Woo Je 
Published: August 2018

AbstractIt is unclear whether non-alcoholic fatty liver disease (NAFLD) is an independent risk factor for cardiovascular disease. We examined the independent impact of NAFLD on the progression of the coronary artery calcification (CAC) score, a well-known marker of atherosclerosis progression. We examined 1,173 asymptomatic participants who underwent repeated CAC score measurement during routine health examinations. The subjects were categorised into four groups based on the presence (+) or absence (−) of NAFLD and metabolic syndrome (MetS). The progression of CAC score was defined as either incident CAC in a CAC-free population at baseline or an increase of ≥2.5 units between the baseline and the final square roots of the CAC scores of participants with detectable CAC at baseline. CAC progression was seen in 18.6% (98/526), 28.3% (77/272), 29.1% (30/103) and 32.0% (87/272) of the subjects with NAFLD(−)/MetS(−), NAFLD(+)/MetS(−), NAFLD(−)/MetS(+) and NAFLD(+)/MetS(+), respectively. The subjects with NAFLD(+)/MetS(+) and NAFLD(+)/MetS(−) had a significantly higher risk of CAC progression than those with NAFLD(−)/MetS(−) (multivariate-adjusted odds ratio [OR]: 1.76; 95% confidence interval [CI]: 1.18–2.62 and multivariate-adjusted OR: 1.53, 95% CI: 1.05–2.23, respectively). NAFLD is an independent risk factor for CAC progression, irrespective of the presence of MetS.
Effect of storage conditions on salivary polyamines quantified via liquid chromatography-mass spectrometry
Authors: Tomita Atsumi , Mori Masayo , Hiwatari Kana , Yamaguchi Eri , Itoi Takao , Sunamura Makoto , Soga Tomoyoshi , Tomita Masaru , Sugimoto Masahiro 
Published: August 2018

AbstractSalivary polyamines are potential non-invasive tools for screening various types of cancers. For clinical use, the reproducibility of these metabolites should be evaluated under various storage conditions, including duration and temperature, to establish standard operating protocols. Polyamines and amino acids in unstimulated whole saliva were quantified via liquid chromatography-mass spectrometry. Concentrations of time course samples were analysed after short-term storage for up to 240 min and long-term storage for up to 8 days under various storage conditions. As expected, storage at the lowest temperature (−18 °C) exerted the least pronounced effects on the quantified values in both tests. At a higher temperature, polyamines were more stable than amino acids, as evident from polyamine profiling. Addition of ethanol significantly stabilized polyamine profiles even at a higher temperature. Comparative processing of saliva revealed a minor effect of the solvent, whereas drying had a more prominent effect on polyamine profiles. Computational analyses evaluated the ability of polyamines to discriminate pancreatic cancer from controls. Repeated noise added tests were designed on the basis of the results of the storage tests; these analyses confirmed that the discriminative abilities were robust. These data contribute to the standardization of salivary storage conditions, thereby highlighting the clinical utility of saliva.
IL-1β, IL-6, TNF- α and CRP in Elderly Patients with Depression or Alzheimer’s disease: Systematic Review and Meta-Analysis
Authors: Ng Ada , Tam Wilson W. , Zhang Melvyn W. , Ho Cyrus S. , Husain Syeda F. , McIntyre Roger S. , Ho Roger C. 
Published: August 2018

AbstractWe carried out systematic review and meta-analysis to evaluate whether peripheral levels of pro-inflammatory markers including Interleukin-1 beta (IL-1β), Interleukin-6 (IL-6), Tumor Necrosis Factor-α (TNF- α) and C-Reactive Protein (CRP) are significantly higher in elderly with depression and Alzheimer’s disease. We searched Pubmed, PsycINFO and Embase, and thirty-four relevant studies (2609 with Depression, 1645 with Alzheimer’s disease and 14363 Controls) were included. Compared with controls, IL-1β (pooled standardized mean difference [SMD]: 0.642; 95% confidence interval [CI]: 0.078–1.206; significant heterogeneity: I2 = 86.28%) and IL-6 (pooled SMD: 0.377; 95% CI: 0.156–0.598; significant heterogeneity: I2 = 88.75%) were significantly elevated in depression. There was no difference in TNF-α (p = 0.351) and CRP (p = 0.05) between those with depression and controls. Compared with controls, IL-1β (pooled SMD: 1.37, 95% CI: 0.06–2.68, significant heterogeneity: I2 = 96.01%) was significantly elevated in Alzheimer’s disease. There were no differences in IL-6 (p = 0.138), TNF-α (p = 0.451) and CRP (p = 0.07) between elderly with Alzheimer’s disease and controls. After Bonferroni adjustment, only IL-6 remained significantly higher in depression. Elderly with depression have higher IL-6 than controls, while those with Alzheimer’s disease did not have higher peripheral inflammatory markers.