bluuebunny/crossref_metadata_2025_split huggingface dataset:
Predicting Nitrate Retention at the Groundwater‐Surface Water Interface in Sandplain Streams
Authors: Stelzer Robert S. , Scott J. Thad 
Published: August 2018

AbstractGroundwater‐surface water ecotones present opportunities for nitrate retention because changes in organic carbon availability, redox potential, and nitrate demand often occur at these locations. Although there have been many measurements of nitrate retention and denitrification at the groundwater‐surface water interface, few investigators have quantitatively predicted where nitrogen transformation occurs in this zone. Our main objective was to describe and predict spatial variation in nitrate retention and removal in shallow groundwater among and within streams in the central sand plains of Wisconsin. We predicted that nitrate transformation rates would be positively related to nitrate and particulate organic carbon availability, a negative nonlinear function of dissolved oxygen availability, and would peak at intermediate rates of groundwater discharge. Five sites on four streams were chosen that spanned an order of magnitude in groundwater nitrate concentration. Nitrate retention and N2 production were quantified by determining how nitrate and N2 fluxes changed along nominal 55‐cm groundwater flow paths. Nitrogen transformation was widespread but highly variable within the study sites. Partial least squares regression models explained a much larger amount of variation in nitrate retention and N2 production at the local scale than at the regional scale. Dissolved oxygen availability and groundwater discharge were the most consistent predictors of nitrate retention at both scales. We conclude that nitrate retention at the groundwater‐surface water interface can be predicted but that more research is necessary to determine if nitrate transformation at this ecotone can be modeled at broader scales.
Climate Change to Offset Improvements in Watershed Acid‐Base Status Provided by Clean Air Act and Amendments: A Model Application in Shenandoah National Park, Virginia
Authors: Robison Andrew L. , Scanlon Todd M. 
Published: August 2018

AbstractThe impact of climate change on watershed acid‐base chemistry is currently understudied. Projecting the future condition of upland watersheds in the southern Appalachians of the United States, where high sulfate adsorption has prevented significant acid‐base recovery, is complicated because of the unknown interaction with likely changes in temperature and precipitation. Here the biogeochemical model PnET‐BGC and statistically downscaled general circulation models were used to evaluate potential effects of future climate on watershed biogeochemistry at White Oak Run in Shenandoah National Park, Virginia. Downscaled climate scenarios on average predict warmer temperatures and greater precipitation for this watershed by the end of the century. Model results suggest the combination of these effects on discharge drive the largest changes in acid‐base chemistry, as increased runoff depletes the soil pool of sulfur and base cations resulting in lower stream concentrations. Superimposed on this abiotic effect is an increased biotic demand for base cations, resulting in an overall loss of alkalinity under projected climate conditions. The predicted loss of alkalinity resulting from climate change is comparable to what would be expected if acid deposition had remained elevated during this century. Specifically, model results indicate the predicted loss of alkalinity resulting from climate change would offset about 68 +/−16% of the modeled gains from the Clean Air Act and Amendments, where the 95% uncertainty bounds are associated with the ensemble of climate predictions applied to the calibrated biogeochemical model. Such an outcome would represent a considerable setback from one of the desired effects of clean air regulation.
Ocean Circulation in the Toarcian (Early Jurassic): A Key Control on Deoxygenation and Carbon Burial on the European Shelf
Authors: Ruvalcaba Baroni Itzel , Pohl Alexandre , van Helmond Niels A. G. M. , Papadomanolaki Nina M. , Coe Angela L. , Cohen Anthony S. , van de Schootbrugge Bas , Donnadieu Yannick , Slomp Caroline P. 
Published: August 2018

AbstractThe Toarcian Oceanic Anoxic Event (T‐OAE, ∼183 Myr) was a long‐lasting episode of ocean deoxygenation during the Early Jurassic. The event is related to a period of global warming and characterized by major perturbations to the hydrological and carbon cycles with high rates of organic matter burial in shelf seas. Ocean circulation during the Toarcian and its influence on marine biogeochemical cycles are still not fully understood. Here we assess the spatial extent of anoxia in the NW Tethys Ocean during the T‐OAE, the relationship with ocean circulation and the impact on organic carbon burial, using new and existing sedimentary records from the European Epicontinental Shelf in combination with general circulation model results. We demonstrate that bottom waters on the southwestern part of the shelf were mainly oxic during the T‐OAE, while those in the northeastern basins were mostly anoxic or even sulfidic. Results for two ocean‐atmosphere models (Fast Ocean‐Atmosphere Model and Massachusetts Institute of Technology general circulation model) suggest the presence of a strong clockwise gyre over the European Epicontinental Shelf, which brought oxygenated equatorial waters from the Tethys Ocean to the southern shelf. The northward limb of the gyre was significantly weakened due to the rough bathymetry of the northern shelf, making this relative small region highly sensitive to local ocean stratification. These sluggish ocean dynamics promoted bottom water anoxia and enhanced burial of organic carbon in the northeastern basins, which accounted for 3–5% of the total carbon extracted from the ocean‐atmosphere system as recorded by the positive carbon isotope shift.
Prediction of the Dst Index and Analysis of Its Dependence on Solar Wind Parameters Using Neural Network
Authors: Lethy Ahmed , El‐Eraki Mohamed A. , Samy Aalaa , Deebes Hanafy A. 
Published: August 2018

AbstractIn this work, we propose an artificial neural network (ANN) with seven input parameters for the prediction of disturbance storm time (Dst) index 1 to 12 hr ahead. The ANN uses past near‐Earth solar wind parameter values to forecast the Dst. The input parameters are the solar wind interplanetary magnetic field, north‐south component of interplanetary magnetic field, temperature, density, speed, pressure, and electric field. The ANN was trained on the data period from 1 January 2007 to 31 December 2015, which contains 78,888 hourly data samples. While the period from 1 January 2016 to 31 May 2017 was used to test the prediction capabilities of the ANN. Several ANN structures were tested and the best results were determined using the correlation coefficient (R) during the training and prediction phases. The results indicate an adequate accuracy of R = 0.876 for prediction 2 hr in advance and R = 0.857 for prediction 12 hr in advance. The power of the proposed ANN was illustrated using the strongest six storms recorded during the prediction period. Generally, the duration and number of the input parameters significantly affect the training and prediction performance of the applied ANN. The results are outstanding in term of accuracy when considering a medium‐term prediction of 12 hr in advance and in terms of timing of the Dst minimum occurrence. In addition, the results show a strong dependence on the solar wind electric current.
Low‐noise dynamic comparator circuit with selectable input‐referred thermal noise voltage
Authors: Yazid M. 
Published: August 2018

A new method for reducing input‐referred thermal noise of dynamic comparator circuit without increasing load capacitance as commonly used in the conventional method is proposed. An implementation circuit with selectable low‐noise mode operation is presented, which enable both low‐noise mode and standard mode operation by a single circuit. Simulation in 180 nm CMOS process technology shows that the proposed new method and circuit topology can achieve up to 90% increase in gain of comparator first stage, resulting in up to 40% decrease in input‐referred thermal noise voltage, compared with a conventional circuit with similar load capacitance. The proposed circuit is also able to operate with similar performance as the conventional circuit when low‐noise mode operation is not necessary.
Capacitor mismatch calibration method for SAR ADC with minimum area and power penalty
Authors: Yang Xiaolin , Zhao Menglian , Wu Xiaobo 
Published: August 2018

A novel capacitor mismatch calibration method is presented to compensate the capacitor mismatches in a successive approximation register (SAR) ADC. The method features a new weight‐balancing split capacitive DAC which allows automatic extraction and calibration of the capacitor mismatches by itself. As a result, the ADC's resolution can be substantially improved with minimum area and power penalty. The calibration method was verified and implemented in a 14 bit, 10 kS/s SAR ADC, fabricated in a 0.13 µm standard CMOS process. The measured signal‐to‐noise‐plus‐distortion and spurious‐free dynamic range are 72.7 and 86 dB after calibration with 13.6 and 21.8 dB improvements, respectively. The total power consumption is 15.2 µW at a 1.2 V supply voltage.
Cogging torque reduction by eccentric structure of teeth in external rotor permanent magnet synchronous motors
Authors: Wang Kai , Liang Yanping , Wang Dongmei , Wang Chenguang 
Published: August 2018

Aiming at the problem of torque ripple caused by cogging torque in the external rotor permanent magnet synchronous motor, this study proposes a method for reducing the cogging torque by the eccentric structure of stator teeth. Taking a 3 kW external rotor permanent magnet synchronous motor as an example, the validity of the method proposed is verified by theoretical analysis and finite element calculation. Finally, the other performances of the models with different teeth eccentricities are compared, and a prototype is manufactured to verify the correctness of the simulation results. The research shows that the eccentric structure of stator teeth does not affect the other performances of the motor greatly while reducing the cogging torque of external rotor permanent magnet synchronous motor effectively.
Smart PV and SmartPark inverters as suppressors of TOV phenomenon in distribution systems
Authors: Rangarajan Shriram Srinivasarangan , Collins E. Randolph , Fox J. Curtiss 
Published: August 2018

This study proposes a new application and a novel control scheme for utilising Smart PV and Smart Park inverters to mitigate temporary overvoltage (TOV) phenomenon in distribution systems. As more number of the inverter‐based distributed generators such as PV are connected to a medium‐ and low‐voltage distribution systems, TOV phenomenon becomes more prevalent during single line to ground fault. Currently, the IEEE 142 ‘Effective grounding’ technique has been the reference for various grounding schemes to prevent TOV. This study explores the potential of low‐cost and a novel solution for the first time that utilises a specialised controller associated with PV/SmartPark inverters (Smart inverters) as a TOV suppressor. The efficacy of the aforementioned novel application has been demonstrated on a simplified benchmark system of the IEEE Standard 399‐1997 with few modifications. A 4 MW conventional PV plant is considered along with 10 MVAR Smart inverter connected to the point of common coupling. During normal operation of the distribution systems, the Smart inverter controller acts in a voltage regulation mode to curtail the voltage rise due to reverse power flow from the 4 MW PV plant. During a fault condition, the TOV sensor enables the TOV control to suppress the violated limits of voltages in the healthy phases to an acceptable value.
Enzymatic browning reaction of apple juices prepared using a blender and a low-speed masticating household juicer
Authors: Park Shin-Young , Kang Tae-Min , Kim Min-Ju , Kim Myo-Jeong 
Published: August 2018

ABSTRACT
The aim of this study was to investigate the effect of juicer type (blender or LSM household juicer) on the browning reaction of apple juice and evaluate the remaining antioxidant activity in the juice. The blender apple juice showed a darker brown color and 4.5 times higher PPO activity than LSM apple juice. This result suggested that the blender caused severer damage to plastids in cells leading to leakage of PPO into the juice than the LSM juicer. The total polyphenol and flavonoid content of LSM apple juice was approximately 2 times higher than that of blender apple juice because polyphenols and flavonoids can be used as substrates by PPO. The antioxidant activity of LSM juice was higher than that of blender juice. Together, these results suggested that the LSM juicer is superior to the blender for preparation of fresh apple juices due to the minimization of enzymatic oxidation reactions.
Abbreviations: LSM: low-speed masticating; PPO: polyphenol oxidase; ABTS: 2,2ʹ-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid); DPPH: 2,2-diphenyl-1-picrylhydrazyl
Augmentation of dietary glucosylceramide hydrolysis by the novel bacterium Glucerabacter canisensis NATH-2371T
Authors: Kawata Misho , Suzuki Masato , Akutsu Shoko , Kawahara Natsuki , Tsukamoto Ami , Nobukawa Shohei , Isozaki Ryohei , Yuyama Seika , Asanuma Narito 
Published: August 2018

ABSTRACT
The purpose of this study was to evaluate the effects of intragastrical administration of Glucerabacter canisensis NATH-2371T on glucosylceramide (GluCer) digestion in mice. Although G. canisensis was unable to utilize starch and cellulose, coculture of G. canisensis with mouse fecal bacteria greatly increased GluCer hydrolysis in polysaccharide medium, indicating that G. canisensis grew in competition with other intestinal bacteria. Although most of the administered G. canisensis cells were detected in feces, some cells were present in the colorectum contents, which had GluCer-hydrolyzing activity. These results indicate that G. canisensis can viably transit through the mouse gut. Administration of G. canisensis to mice fed diets supplemented with GluCer or GluCer-containing foods significantly enhanced GluCer hydrolysis. Since G. canisensis did not show acute toxicity, it may be useful as a probiotic to augment GluCer hydrolysis in the large intestine.
Abbreviations: GluCer: glucosylceramide; KPi: potassium phosphate buffer; C-M: chloroform-methanol
Effect of Aurea Helianthus stem extract on anti-melanogenesis
Authors: Kim Yehyang , Lee Sohun , Ryu Ji Hye , Yoon Kee Dong , Shin Song Seok 
Published: August 2018

ABSTRACT
Aurea Helianthus (AH), also known as wild confederate rose or golden sunflower, is a curative herb. It has been used as a medicinal material in China due to its anti-inflammatory, immune regulatory, and anti-oxidant activities. However, its melanogenic effect on skin has not been sufficiently investigated. In this study, we tested whether AH has melanogenic inhibitory activities for the development of effective skin whitening agent. The extract showed inhibition of melanin synthesis and reduced the oxidation of 3, 4-dihydroxyphenilalanine (DOPA) to o-dopaquinone. Additionally, AH downregulated the levels of microphthalmia-associated transcription factor (MITF), tyrosinase and tyrosinase related proteins (TRPs), suggesting that AH has inhibitory effects on melanogenesis. Analysis of the components of AH showed that it contained paprazine and trans-N-feruloyltyramine (FA). We confirmed that the effect of AH resulted from paprazine and FA. Therefore, AH might have potential as an effective candidate for skin whitening.
A Case-Control Study to Identify Community Venues Associated with Genetically-clustered, Multidrug-resistant Tuberculosis Disease in Lima, Peru
Authors: Bui David P , Oren Eyal , Roe Denise J , Brown Heidi E , Harris Robin B , Knight Gwenan M , Gilman Robert H , Grandjean Louis 
Published: August 2018

Abstract

Background
The majority of tuberculosis transmission occurs in community settings. Our primary aim in this study was to assess the association between exposure to community venues and multidrug-resistant (MDR) tuberculosis. Our secondary aim was to describe the social networks of MDR tuberculosis cases and controls.

Methods
We recruited laboratory-confirmed MDR tuberculosis cases and community controls that were matched on age and sex. Whole-genome sequencing was used to identify genetically clustered cases. Venue tracing interviews (nonblinded) were conducted to enumerate community venues frequented by participants. Logistic regression was used to assess the association between MDR tuberculosis and person-time spent in community venues. A location-based social network was constructed, with respondents connected if they reported frequenting the same venue, and an exponential random graph model (ERGM) was fitted to model the network.

Results
We enrolled 59 cases and 65 controls. Participants reported 729 unique venues. The mean number of venues reported was similar in both groups (P = .92). Person-time in healthcare venues (adjusted odds ratio [aOR] = 1.67, P = .01), schools (aOR = 1.53, P &lt; .01), and transportation venues (aOR = 1.25, P = .03) was associated with MDR tuberculosis. Healthcare venues, markets, cinemas, and transportation venues were commonly shared among clustered cases. The ERGM indicated significant community segregation between cases and controls. Case networks were more densely connected.

Conclusions
Exposure to healthcare venues, schools, and transportation venues was associated with MDR tuberculosis. Intervention across the segregated network of case venues may be necessary to effectively stem transmission.
Smoking and HIV in Sub-Saharan Africa: A 25-Country Analysis of the Demographic Health Surveys
Authors: Murphy John D , Liu Benmei , Parascandola Mark 
Published: August 2018

Abstract

Background
Having HIV/AIDS has been associated with a higher prevalence of smoking. Moreover, evidence suggests that people with HIV/AIDS who smoke have poorer treatment and survival outcomes. The HIV–smoking relationship is understudied in sub-Saharan Africa, where tobacco use patterns and HIV prevalence differ greatly from other world regions.

Methods
Cross-sectional data from the Demographic Health Surveys and AIDS Indicator Surveys, representing 25 sub-Saharan African countries, were pooled for analysis (n = 286850). The association between cigarette smoking and HIV status was analyzed through hierarchical logistic regression models. This study also examined the relationship between smokeless tobacco (SLT) use and HIV status.

Results
Smoking prevalence was significantly higher among men who had HIV/AIDS than among men who did not (25.90% vs 16.09%; p &lt; .0001), as was smoking prevalence among women who had HIV/AIDS compared with women who did not (1.15% vs 0.73%; p &lt; .001). Multivariate logistic regression revealed that the odds of smoking among people who had HIV/AIDS was 1.12 times greater than among people who did not when adjusting for socioeconomic, demographic, and sexual risk factors (adjusted OR = 1.12, 95% CI = 1.04% to 1.21%; p &lt; .001). Similarly, multivariate logistic regression revealed that HIV-positive individuals were 34% more likely to use SLT than HIV-negative individuals (adjusted OR = 1.34, 95% CI = 1.17% to 1.53%).

Conclusion
Having HIV was associated with a greater likelihood of smoking cigarettes as well as with using SLT in sub-Saharan Africa. These tobacco use modalities were also associated with male sex and lower socioeconomic status.

Implications
This study shows that in sub-Saharan Africa, as in more studied world regions, having HIV/AIDS is associated with a higher likelihood of smoking cigarettes when adjusting for demographic, socioeconomic, and sexual risk factors. This study also supports the literature stating that cigarette smoking is inversely associated with socioeconomic status, as evidenced by higher smoking prevalence among poorer individuals, less educated individuals, and manual and agricultural laborers.
Employment and occupational outcomes following adolescent-onset mental illness: analysis of a nationally representative French cohort
Authors: Witt Katrina , Milner Allison , Chastang Jean-François , LaMontagne Anthony D , Niedhammer Isabelle 
Published: August 2018

ABSTRACT

Background
There has been little work into the relative effects of adolescent-onset, as compared to lifetime, mental illness on employment, income and occupational outcomes in adulthood.

Methods
Using data from the Santé et Itinéraire Professionnel Survey, a nationally representative survey of 13 648 French working-age people to investigate prospective associations between self-reported mental illness and employment, income and occupational outcomes. We further investigated whether these outcomes would differ for those reporting an onset of mental illness prior to 18 years of age.

Results
Adolescent-onset mental illness was associated with poorer employment outcomes, significantly increased risk of employment in low-skilled occupations, as well as reduced monthly wage earnings.

Conclusions
Results extend understandings of the risks of adolescent-onset mental illness on employment and occupational outcomes and suggest that vocational recovery services should take these factors into account when designing support services for adolescents with mental health problems, particularly for males.
Environments with a high probability of incompatible crosses do not select for mate avoidance in spider mites
Authors: Rodrigues Leonor R , Zélé Flore , Santos Inês , Magalhães Sara 
Published: August 2018

AbstractArthropods are often infected withWolbachiainducing cytoplasmic incompatibility (CI), whereby crosses between uninfected females and infected males yield unviable fertilized offspring. Although uninfected females benefit from avoiding mating withWolbachia-infected males, this behaviour is not present in all host species. Here we measured the prevalence of this behaviour across populations of the spider miteTetranychus urticae. Females from five populations originally fully infected withWolbachiashowed no preference, possibly because they did not face the choice between compatible and incompatible mates in their environment. Hence, to determine whether this behaviour could be selected in populations with intermediateWolbachiainfection frequency, we performed 15 generations of experimental evolution of spider-mite populations under i) fullWolbachiainfection, ii) no infection, or iii) mixed infection. In the latter selection regime, where uninfected females were exposed to infected and uninfected males at every generation, mating duration increased relative to the uninfected regime, suggesting the presence of genetic variation for mating traits. However, mate choice did not evolve. Together, these results show that CI-inducingWolbachiaalone does not necessarily lead to the evolution of pre-copulatory strategies in uninfected hosts, even at intermediate infection frequency.