bluuebunny/crossref_metadata_2025_split huggingface dataset:
Aphid‐tending ants on introduced fennel: can resources derived from non‐native plants alter the trophic position of higher‐order consumers?
Authors: HANNA CAUSE , NAUGHTON IDA , BOSER CHRISTINA , HOLWAY DAVID A. 
Published: November 2016

1. Although plant invasions often reduce insect abundance and diversity, non‐native plants that support phytophagous insects can subsidise higher trophic levels via elevated herbivore abundance.2. Here ant–aphid interactions on non‐native fennel on Santa Cruz Island, California are examined. Fennel hosts abundant, honeydew‐producing fennel aphids. The patchiness of fennel and the relative lack of honeydew‐producing insects on other plants at our study sites suggest that assimilation of fennel‐derived honeydew would increase the abundance and decrease the trophic position of the omnivorous, aphid‐tending Argentine ant.3. To assess the strength of the ant–aphid interaction, a comparison of ant abundance on and adjacent to fennel prior to and 3 weeks after experimental aphid removal was performed. Compared with control plants with aphids, ants declined in abundance on and around fennel plants following aphid removal. At the habitat scale, pitfall traps in fennel‐dominated habitats captured more ants than in fennel‐free scrub habitats.4. To determine if assimilation of aphid‐produced honeydew reduces the ant's trophic position, variation in δ15N values among ants, plants and other arthropods was analysed. Unexpectedly, δ15N values for ants in fennel‐dominated habitats were higher than those of arthropod predators from the same sites and also higher than those of ants from fennel‐free habitats.5. Our results illustrate how introduced plants that support phytophagous insects appear to transfer energy to higher trophic levels via elevated herbivore abundance. Although assimilation of fennel‐derived honeydew did not appear to reduce consumer trophic position, spatial variation in alternative food resources might obscure contributions from honeydew.
Added value of multimodal computed tomography imaging: analysis of 1994 acute ischaemic strokes
Authors: Bill O. , Faouzi M. , Meuli R. , Maeder P. , Wintermark M. , Michel P. 
Published: November 2016

Background and purposeMultimodal computed tomography (CT) based imaging (MCTI) is widely used in acute ischaemic stroke. It was postulated that the use of MCTI is associated with improved patient outcome without causing harm.MethodsAll patients with an acute ischaemic stroke and CT‐based imaging within 24 h from the ASTRAL (Acute Stroke Registry and Analysis of Lausanne) registry were included. Preceding demographic, clinical, biological, radiological and follow‐up data were collected. Significant predictors of MCTI use were identified retrospectively to go on to fit a multivariable analysis. Then, patients undergoing additional CT angiography (CTA) or CTA and perfusion CT (CTP) were compared with non‐contrast CT only patients with regard to 3‐month favourable outcome (modified Rankin Scale score ≤2), 12‐month mortality, stroke mechanism, short‐term renal failure, use of ancillary diagnostic tests, duration of hospitalization and 12‐month stroke recurrence.ResultsOf the 1994 included patients, 273 had only non‐contrast CT, 411 had both non‐contrast CT and CTA and 1310 had all three examinations. Factors independently associated with MCTI were younger age, low pre‐stroke modified Rankin Scale score, low creatinine value, known stroke onset, anterior circulation stroke, anticoagulation or antihypertensive therapy (CTA only) and higher National Institutes of Health Stroke Scale scores (CTP only). After adjustment, MCTI was associated with a 50% reduction of 12‐month mortality and a lower likelihood of unknown stroke mechanism. No association was found between MCTI and 3‐month outcome, contrast‐induced nephropathy, hospitalization duration, number of ancillary diagnostic tests or with stroke recurrence.ConclusionOur study shows an association of MCTI use with lower adjusted 12‐month mortality, better identification of the stroke mechanism and no signs of harm.
Timing of Physical Activity, Apolipoprotein E ε4 Genotype, and Risk of Incident Mild Cognitive Impairment
Authors: Krell‐Roesch Janina , Pink Anna , Roberts Rosebud O. , Stokin Gorazd B. , Mielke Michelle M. , Spangehl Kathleen A. , Bartley Mairead M. , Knopman David S. , Christianson Teresa J.H. , Petersen Ronald C. , Geda Yonas E. 
Published: November 2016

ObjectivesTo investigate the timing (mid‐ vs late life) of physical activity, apolipoprotein (APO)E ε4, and risk of incident mild cognitive impairment (MCI).DesignProspective cohort study.SettingMayo Clinic Study of Aging (Olmsted County, MN).ParticipantsCognitively normal elderly adults (N = 1,830, median age 78, 50.2% female).MeasurementsLight, moderate, and vigorous physical activities in mid‐ and late life were assessed using a validated questionnaire. An expert consensus panel measured MCI based on published criteria. Cox proportional hazards models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) with age as a time scale after adjusting for sex, education, medical comorbidity, and depression.ResultsLight (HR = 0.58, 95% CI = 0.43–0.79) and vigorous (HR = 0.78, 95% CI = 0.63–0.97) physical activity in midlife were associated with lower risk of incident MCI. The association between moderate activity and incident MCI was not significant (HR = 0.85, 95% CI = 0.67–1.09). In late life, light (HR = 0.75, 95% CI = 0.58–0.97) and moderate (HR = 0.81, 95% CI = 0.66–0.99) but not vigorous physical activity were associated with lower risk of incident MCI. A synergistic interaction was also observed between mid‐ and late‐life activity in reducing risk of incident MCI. Furthermore, APOE ε4 carriers who did not exercise had a higher risk of incident MCI than noncarriers who reported physical activity.ConclusionPhysical activity reduced the risk of incident MCI. Exercising in mid‐ and late life had an additive synergistic interaction in reducing the risk of MCI.
A differentially regulated AP2/ERF transcription factor gene cluster acts downstream of a MAP kinase cascade to modulate terpenoid indole alkaloid biosynthesis in Catharanthus roseus
Authors: Paul Priyanka , Singh Sanjay K. , Patra Barunava , Sui Xueyi , Pattanaik Sitakanta , Yuan Ling 
Published: November 2016

Summary

Catharanthus roseus produces bioactive terpenoid indole alkaloids (TIAs), including the chemotherapeutics, vincristine and vinblastine. Transcriptional regulation of TIA biosynthesis is not fully understood.

The jasmonic acid (JA)‐responsive AP2/ERF transcription factor (TF), ORCA3, and its regulator, CrMYC2, play key roles in TIA biosynthesis. ORCA3 forms a physical cluster with two uncharacterized AP2/ERFs, ORCA4 and 5. Here, we report that (1) the ORCA gene cluster is differentially regulated; (2) ORCA4, while overlapping functionally with ORCA3, modulates an additional set of TIA genes. Unlike ORCA3, ORCA4 overexpression resulted in dramatic increase of TIA accumulation in C. roseus hairy roots. In addition, CrMYC2 is capable of activating ORCA3 and co‐regulating TIA pathway genes concomitantly with ORCA3.

The ORCA gene cluster and CrMYC2 act downstream of a MAP kinase cascade that includes a previously uncharacterized MAP kinase kinase, CrMAPKK1. Overexpression of CrMAPKK1 in C. roseus hairy roots upregulated TIA pathways genes and increased TIA accumulation.

This work provides detailed characterization of a TF gene cluster and advances our understanding of the transcriptional and post‐translational regulatory mechanisms that govern TIA biosynthesis in C. roseus.
Structure and function of adipokinetic hormones of the large white butterfly Pieris brassicae
Authors: Marco Heather G. , Gäde Gerd 
Published: November 2016

AbstractThe large white butterfly Pieris brassicae L. (also called cabbage white) is very common in Europe, Asia and the northern region of Africa, and has also been found in South Africa during approximately the last 20 years. The species is considered a pest insect, with larvae attacking brassicaceous crops. The adult is a strong migratory flyer and new territory can be infested this way. As a first step to investigate methods for combating this pest species, the present study aims to determine the complement of adipokinetic peptides, here generically referred to as adipokinetic hormones (AKHs), which are required to regulate the mobilization of fuels for insect flight. Biological assays, as well as mass spectrometry, reveal information about the presence, structure and function of AKHs in P. brassicae: a methanolic extract of the corpora cardiaca has hypertrehalosaemic activity in cockroaches, does not cause hyperlipaemia in locusts, and has adipokinetic activity in P. brassicae itself. Liquid‐chromatography electrospray ion trap mass spectrometry reveals three peptides that can be associated with the AKH family: the non‐amidated undecapeptide Vanca‐AKH (pELTFTSSWGGK‐OH), the nonapeptide Manse‐AKH (pELTFTSSWG amide) and the novel octapeptide Piebr‐AKH (pELTFSSGW amide). Sequence confirmation of all three assigned structures is obtained from matching mass spectrometry spectra from synthetic and native peptides. Moreover, the synthetic peptides Manse‐AKH and Piebr‐AKH have significant hyperlipaemic (=adipokinetic) activity when injected into newly‐emerged adult cabbage white butterflies. The non‐amidated Vanca‐AKH is, apparently, incompletely processed Manse‐AKH without hormonal activity. Simulated dispersal flight is able to release AKHs, as indicated by the higher concentration of lipids in the haemolymph of adult P. brassicae after activity and rest periods.
“I Don't Agree with Giving Cash”: A Survey Experiment Examining Support for Public Assistance
Authors: Campbell Colin , Gaddis S. Michael 
Published: November 2016

ObjectiveExisting research on support for anti‐poverty programs largely focuses on broad categories of welfare. In this article, we examine variations in support across different public assistance programs.MethodsWe use an experimental survey design to examine whether support for public assistance is dependent on the type of aid offered.ResultsWe find that programs that offer benefits in‐kind are more popular than cash transfers. Moreover, food stamps and child‐care subsidies enjoy more support than housing assistance. Open‐ended survey responses show that when evaluating anti‐poverty programs, respondents adopt one of two perspectives: (1) cash assistance is problematic but other forms of assistance are acceptable or (2) any assistance is problematic.ConclusionBy too narrowly focusing on welfare, social scientists run the risk of developing theories and explanations that may not apply to the much larger part of the safety net that is delivered in‐kind.
Identification of a Plasmid‐Mediated Quinolone Resistance Gene in Salmonella Isolates from Texas Dairy Farm Environmental Samples
Authors: Cummings K. J. , Rodriguez‐Rivera L. D. , Norman K. N. , Ohta N. , Scott H. M. 
Published: November 2016

SummaryA recent increase in plasmid‐mediated quinolone resistance (PMQR) has been detected among Salmonella isolated from humans in the United States, and it is necessary to determine the sources of human infection. We had previously isolated Salmonella from dairy farm environmental samples collected in Texas, and isolates were tested for anti‐microbial susceptibility. Two isolates, serotyped as Salmonella Muenster, showed the discordant pattern of nalidixic acid susceptibility and intermediate susceptibility to ciprofloxacin. For this project, whole‐genome sequencing of both isolates was performed to detect genes associated with quinolone resistance. The plasmid‐mediated qnrB19 gene and IncR plasmid type were identified in both isolates. To our knowledge, this is the first report of PMQR in Salmonella isolated from food animals or agricultural environments in the United States.
Impact of vesicular glutamate leakage on synaptic transmission at the calyx of Held
Authors: Takami Chihiro , Eguchi Kohgaku , Hori Tetsuya , Takahashi Tomoyuki 
Published: November 2016

Key points
It is controversial whether glutamate can leak out of vesicles in the nerve terminal.
To address this issue, we abolished vesicular glutamate uptake by washing out presynaptic cytosolic glutamate or by blocking vacuolar ATPase activity using bafilomycin A1.
In the absence of vesicular glutamate uptake, both spontaneous and nerve‐evoked EPSCs underwent a rundown, suggesting that vesicular glutamate can leak out of vesicles.
However, the rundown of evoked EPSCs was caused mainly by accumulation of unfilled vesicles after exocytic release of glutamate, suggesting a minor influence of glutamate leakage on synaptic transmission.
AbstractGlutamate leaks out of synaptic vesicles when the transvesicular proton gradient is dissipated in isolated vesicle preparations. In the nerve terminal, however, it is controversial whether glutamate can leak out of vesicles. To address this issue, we abolished vesicular glutamate uptake by washing out presynaptic cytosolic glutamate in whole‐cell dialysis or by blocking vacuolar ATPase using bafilomycin A1 (Baf) at the calyx of Held in mouse brainstem slices. Presynaptic glutamate washout or Baf application reduced the mean amplitude and frequency of spontaneous miniature (m)EPSCs and the mean amplitude of EPSCs evoked every 10 min. The percentage reduction of mEPSC amplitude was much less than that of EPSC amplitude or mEPSC frequency, and tended to reach a plateau. The mean amplitude of mEPSCs after glutamate washout or Baf application remained high above the detection limit, deduced from the reduction of mEPSC amplitude by the AMPA receptor blocker 6‐cyano‐7‐nitroquinoxaline‐2,3‐dione. Membrane capacitance measurements from presynaptic terminals indicated no effect of glutamate washout on exocytosis or endocytosis of synaptic vesicles. We conclude that glutamate can leak out of vesicles unless it is continuously taken up from presynaptic cytosol. However, the magnitude of glutamate leakage was small and had only a minor effect on synaptic responses. In contrast, prominent rundowns of EPSC amplitude and mEPSC frequency observed after glutamate washout or Baf application are likely to be caused by accumulation of unfilled vesicles in presynaptic terminals retrieved after spontaneous and evoked glutamate release.
Fuel Cell Temperature Control With a Pre-Combustor in SOFC Gas Turbine Hybrids During Load Changes
Authors: Zaccaria Valentina , Branum Zachary , Tucker David 
Published: November 2016

The use of high temperature fuel cells, such as Solid Oxide Fuel Cells (SOFCs), for power generation, is considered a very efficient and clean solution to conservation of energy resources. Especially when the SOFC is coupled with a gas turbine, the global system efficiency can go beyond 70% on natural gas LHV. However, the durability of the ceramic material and the system operability can be significantly penalized by thermal stresses due to temperature fluctuations and non-even temperature distributions. Thermal management of the cell during load following is therefore very critical.
The purpose of this work was to develop and test a pre-combustor model for real-time applications in hardware-based simulations, and to implement a control strategy in order to keep cathode inlet temperature as constant as possible during different operative conditions of the system. The real-time model of the pre-combustor was incorporated into the existing SOFC model and tested in a hybrid system facility, where a physical gas turbine and hardware components were coupled with a cyber-physical fuel cell for flexible, accurate, and cost-reduced simulations.
The control of the fuel flow to the pre-combustor was proven to be very effective in maintaining a constant cathode inlet temperature during a step change in fuel cell load. After imposing a 20 A load variation to the fuel cell, the controller managed to keep the temperature deviation from the nominal value below 0.3% (2 K). Temperature gradients along the cell were maintained below 10 K/cm. An efficiency analysis was performed in order to evaluate the impact of the pre-combustor on the overall system efficiency.
On-Line Performance Monitoring and Diagnostics for Large Combined Cycle Power Plant
Authors: Chudnovsky B. , Levin L. , Talanker A. , Mankovsky V. , Kunin A. 
Published: November 2016

Diagnostics of large size combined-cycle power plant components (such as: Gas Turbine, HRSG, Steam Turbine and Condenser) plays a significant role in improving power plant performance, availability, reliability and maintenance scheduling. In order to prevent various faults in cycle operation and as a result a reliability reduction, special monitoring and diagnostic techniques is required, for engineering analysis and utility production management.
In this sense an on-line supervision system has developed and implemented for 370 MW combined-cycle. The advanced diagnostic methodology is based on a comparison between actual and target conditions. The actual conditions are calculated using data set acquired continuously from the power plant acquisition system. The target conditions are calculated either as a defined actual best operation (Manufacturer heat balances) or by means of a physical model that reproduces boiler and plant performance at off-design. Both sets of data are then compared to find the reason of performance deviation and then used to monitor plant degradation, to support plant maintenance and to assist on-line troubleshooting. The performance calculation module provides a complete Gas Turbine, HRSG and Steam Turbine island heat balance and operating parameters. This paper describes a study where an on-line performance monitoring tool was employed for continuously evaluating power plant performance. The methodology developed and summarized herein has been successfully applied to large size 360–370 MW combined cycles based on GE and Siemens Gas Turbines, showing good capabilities in estimating the degradation of the main equipment during plant lifetime. Consequently, it is a useful tool for power plant operation and maintenance.
Damage Mechanisms Found in Generator Rotor 18Mn18Cr Retaining Rings
Authors: Moore William 
Published: November 2016

Generator rotor retaining rings are one of the most highly stressed components in the generator rotor. Additionally, some retaining ring materials such as 18Mn5Cr, have been susceptible to Stress Corrosion Cracking (SCC). 18Mn18Cr retaining ring material has been used to replace older 18Mn5Cr material rings with great success. The 18Mn18Cr material has been found to be resistant to SCC in the presence of moisture. Recently, one OEM (Original Equipment Manufacturer) called for inspections of 18Mn18Cr rings, despite its reliable performance in the industry. Although resistant to SCC, some 18Mn18Cr rings have been found with cracks and other damage. The author’s company felt that it would be of value to go back through past job records with rotors that were identified to have 18Mn18Cr retaining rings, and review those records and report on the results of ring inspections due to damage. The author’s company typically rewinds dozens of rotors per year, with many of the rings manufactured from 18Mn18Cr. As part of a rewind, rings are disassembled and inspected. Of course, many rewinds are done because of failures, mostly related to the field winding. An XRF (X-Ray Fluorescence) analyzer is used to determine a ring’s composition. It has excellent accuracy, and can easily distinguish between 18Mn18Cr material and other non-magnetic steels, such as the once common 18Mn5Cr. Magnetic rings are easily distinguishable by a magnet, by manufacturer and rating, and / or by ventilation method.
A total of seventeen (17) 18Mn18Cr ring metallurgical investigation reports were reviewed. These metallurgical investigations were conducted between 2008 and 2014. Reports reviewed included only those retaining ring inspections that were done to diagnose some visible damage to one or two retaining rings. In other words, if an 18Mn18Cr retaining had some indication of damage, the detailed inspection report and analysis was included and reviewed as part of this paper. Rings that were inspected and had no issues are not included. Rings that had damage due to some obvious man-made issues were not included. For example, one generator rotor had an 18Mn18Cr ring that had an obvious grinding wheel cut. The owner was aware that this damage had occurred during a prior repair. This metallurgical investigation was not included in this study. Another finding not included in this study was an 18Mn18Cr retaining ring with a high hardness variation, well beyond the tolerance standards and acceptance criteria used by NEC. Since there was no physical damage to the ring surface and no cracking, pitting or other abnormality present, this ring’s inspection report was also excluded. Only rings with some type of visual evidence of pitting, corrosion, fretting or material upset were included and make up the 17 generator rotors.
A Study on Superheat Utilization of Extraction Steam in a 1000MW Double Reheat Ultra-Supercritical Unit
Authors: Wang Weiliang , Zhang Hai , Lv Junfu , Ni Weidou , Li Yongsheng , Liu Jianmin 
Published: November 2016

The world’s first 1000MW double reheat ultrasupercritical unit has been in operation since September 25th, 2015 in Taizhou, China. The thermal efficiency at turbine heat-rate acceptance (THA) condition is around 51%, which is the highest among all condensing units in coal-fired power plants around the world. However, the resultant superheat degree of the extraction steam is relatively high, leading to a large temperature difference in heat transfer process in the regenerative system, thereby a great exergy loss.
In order to utilize the superheat of turbine bleeds more effectively, we present a scheme by employing an outer steam cooler (OSC) after the last high pressure heater in series to use the superheat to heat the feed water. Based on the newly installed unit in Taizhou, we examine the energy saving effect of the superheat utilization of different bleeds and their possible combinations respectively. The influencing factors of the mass flow rate, superheat, and effective superheat of the extraction steam are studied.
Thermodynamic analyses revealed that the second extraction steam has not only high effective superheat, but also large mass flow rate, so in the overall efficiency improvement it ranks first and the third extraction steam ranks second. Although the fourth extraction steam has the largest superheat, it ranks third as the result of relatively lower mass flow rate. It was found that at nominal load, by adopting OSC’s to utilize the superheat of the second to sixth extraction steam, temperature of the feed water can increase by 8.1 °C, 3.5 °C, 2.6 °C, 1.1 °C, and 1 °C respectively, and the net coal consumption reduces by 0.73g/kWh, 0.47g/kWh, 0.40g/kWh, 0.21g/kWh and 0.22g/kWh accordingly.
Consequently, three possible schemes are recommended for future design: one is to adopt one OSC to utilize the superheat of the second extraction steam, in return of 8.1°C increment in feed water temperature and 0.73g/kWh reduction of the net coal consumption; the second is to adopt two OSC’s to utilize the superheat of the second and third extraction steam at the same time, in return of 11.4 °C increment in feed water temperature and 1.21g/kWh reduction of the net coal consumption; and the last is to apply three OSC’s to utilize the superheat of the second to the fourth extraction steam simultaneously, to achieve 13.9°C increment in feed water temperature, and 1.62g/kWh reduction of the net coal consumption.