bluuebunny/crossref_metadata_2025_split huggingface dataset:
Assessment of degradation equivalent operating time for aircraft gas turbine engines
Authors: Alozie O. , Li Y.G. , Diakostefanis M. , Wu X. , Shong X. , Ren W. 
Published: January 2020

ABSTRACTThis paper presents a novel method for quantifying the effect of ambient, environmental and operating conditions on the progression of degradation in aircraft gas turbines based on the measured engine and environmental parameters. The proposed equivalent operating time (EOT) model considers the degradation modes of fouling, erosion, and blade-tip wear due to creep strain, and expresses the actual degradation rate over the engine clock time relative to a pre-defined reference condition. In this work, the effects of changing environmental and engine operating conditions on the EOT for the core engine booster compressor and the high-pressure turbine were assessed by performance simulation with an engine model. The application to a single and multiple flight scenarios showed that, compared to the actual engine clock time, the EOT provides a clear description of component degradation, prediction of remaining useful life, and sufficient margin for maintenance action to be planned and performed before functional failure.
The implications of CEO power on the relationship between firm resources and innovation
Authors: Mousa Fariss-Terry , Chowdhury Jaideep , Gallagher Scott R. 
Published: January 2020

AbstractWe examine the link between firm resources and firm innovation intensity, especially the drivers of innovation and organizational slack. We extend the organizational slack and innovation literature by examining its interplay with CEO power and industry level constraints on that power. We examine the influence of human resource slack, CEO power, and industry concentration on R&D intensity. Our study examines all publicly traded US firms over a 10-year period, giving us over 13,400 firm years to look at. Our results indicate that organizations with excess human capacity do on average show higher investments in R&D. However, we also find that in concentrated industries, where CEOs are less constrained by competitive pressure, powerful CEOs do interfere in this strategic choice and weaken the slack–innovation relationship. Even though CEO's in these situations may have sufficient slack resources, they appear inclined to reallocate such resources to purposes other than innovation.
How Valuable Is a Presidential Cabinet? Measuring Ministries’ Political Attractiveness in Brazil
Authors: Mauerberg Arnaldo , Pereira Carlos 
Published: January 2020

ABSTRACTHow valuable is a cabinet position? While the current literature does not ignore the reality that ministries differ from one another, it does not offer either theoretical or methodological procedures to assess such differences. This article introduces a refined measure of coalescence degree that considers several characteristics ministries may have, as well as politicians’ preferences about cabinet appointments. We estimate the effect of this alternative measure of coalescence on the president’s legislative success using large Brazilian datasets from 1995 to 2014 and an elite survey conducted with 62 Brazilian legislators. Controlling for other coalition management variables (coalition size and ideological heterogeneity), our refined coalescence metric turns out to be a more appropriate tool to assess the president’s performance in Congress.
A Troubled Collaboration:Cartonerosand the PRO Administrations in Buenos Aires
Authors: Gutiérrez Ricardo A. 
Published: January 2020

ABSTRACTCan popular organizations engage with the state in a lasting collaborative interaction that benefits their interests without being politically co-opted or captured? This article addresses this question by analyzing the interaction betweencartoneroorganizations and the PRO administrations in Buenos Aires City between 2002 and 2018. It shows howcartonerosmanaged to prompt a change in the PRO’s policies on recyclable waste collection. The article’s main arguments are that popular organizations’ opportunity to gain formal access to the state without losing their autonomy is related to the strategic orientations of both the popular organization and the ruling party, and that such a possibility increases when the popular organization is not part of the incumbent party coalition. The “troubled collaboration” betweencartonerosand the PRO was possible due both to thecartoneros’combination of contentious and institutionalized actions and to an important change in the PRO’s strategic orientation towardcartoneros.
Analysis of deficit irrigation strategies by using SUBSTOR-Potato model in a semi-arid area
Authors: Montoya F. , Camargo D. , Córcoles J. I. , Domínguez A. , Ortega J. F. 
Published: January 2020

AbstractIn areas where water is scarce, the use of regulated deficit irrigation, combined with decision support system tools, may decrease the impact of agriculture on natural water resources, as well as on energy consumption, thereby improving the profitability of farms. With this aim, the SUBSTOR-Potato model (incorporated in the DSSAT Program) was evaluated with a 2-year field test (2011 and 2012) conducted in a semi-arid area (Albacete, Spain) applying four irrigation levels (120, 100, 80 and 60% of irrigation requirements). Subsequently, the model was used for simulating the potato yield under several deficit irrigation strategies (ISs) during 30 years of a semi-arid climate (1988–2017) and determining the most profitable option. The considered ISs were deemed those most suitable from the yield and water productivity point of view by some authors. The model performance for tuber yield was satisfactory with an index of agreement >0.91 and errors between 0.71 and 3.06 × 103 kg/ha. The ISs simulated with SUBSTOR-Potato showed that slight deficit irrigation (5–10%) may increase the water productivity and profitability of the farms. Moreover, tuber formation (from onset of tuber initiation to harvest) was shown to be the most sensitive stage, therefore it is highly recommended to avoid deficit during this stage, which would cause a large reduction in yield (around 8 t/ha, depending on the level of deficit suffered by the crop).
Congenital ductus arteriosus aneurysm in association with MYH11 mutation: a case report
Authors: Ardhanari Mohanageetha , Swaminathan Sethuraman 
Published: January 2020

AbstractCongenital ductus arteriosus aneurysms develop in the third trimester of fetal life, possibly due to abnormal intimal cushion formation or elastin expression in the ductal wall. It is often diagnosed in infants before 2 months of age. Most have a benign course and resolve spontaneously. However, life-threatening complications have been reported. We report a case of large ductal aneurysm diagnosed incidentally in a neonate, in whom there was a novel mutation in the smooth muscle myosin protein gene—MYH11.
Non-iodized salt consumption among women of reproductive age in sub-Saharan Africa: a population-based study
Authors: Ba Djibril M , Ssentongo Paddy , Liao Duanping , Du Ping , Kjerulff Kristen H 
Published: January 2020

AbstractObjective:To identify countries in sub-Saharan Africa (SSA) that have not yet achieved at least 90 % universal salt iodization and factors associated with the consumption of non-iodized salt among women of reproductive age.Design:A cross-sectional study using data from Demographic and Health Surveys (DHS). The presence of iodine in household salt (iodized or non-iodized), which was tested during the survey process, was the study outcome. Multivariable logistic regression models were used to determine independent factors associated with the consumption of non-iodized salt among women of reproductive age.Setting:There were eleven countries in SSA that participated in the DHS since 2015 and measured the presence of iodine in household salt.Participants:Women (n 108 318) aged 15–49 years.Results:Countries with the highest rate of non-iodized salt were Senegal (29·5 %) followed by Tanzania (21·3 %), Ethiopia (14·0 %), Malawi (11·6 %) and Angola (10·8 %). The rate of non-iodized salt was less than 1 % in Rwanda (0·3 %), Uganda (0·5 %) and Burundi (0·8 %). Stepwise multivariable logistic regression showed that women were more likely to be using non-iodized salt (adjusted OR; 95 % CI) if they were poor (1·62; 1·48, 1·78), pregnant (1·16; 1·04, 1·29), aged 15–24 years (v. older: 1·14; 1·04, 1·24) and were not literate (1·14; 1·06, 1·23).Conclusions:The use of non-iodized salt varies among SSA countries. The higher level of use of non-iodized salt among poor, young women and pregnant women is particularly concerning.
Acute toxicity profile of three-dimensional conformal concurrent chemoradiation in carcinoma cervix: an institutional experience
Authors: Tudu Rajanigandha , Kumar Anup , Singh Rashmi , Raina Payal 
Published: January 2020

AbstractBackground:Concurrent chemoradiation is the definitive treatment for advanced cervical cancer. Pelvic radiation is known to damage the adjacent normal tissues thereby causing acute toxicities. The modern conformal radiation techniques like three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy are known to reduce the toxicities and improve clinical outcomes.Aim:To retrospectively evaluate the frequency and severity of acute toxicities encountered during concurrent chemoradiation of locally advanced cancer cervix treated with 3D-CRT.Methods:The medical case records of 174 cervical cancer patients treated between November 2015 and November 2018 were studied. One hundred and thirteen histologically proven locally advanced cancer cervix patients (Stage IIB–IIIB) treated with concurrent 3D conformal chemoradiation between were included in the study. Patients received 46 Gy in 23 fractions with concurrent weekly cisplatin (40 mg/m2) on days 1, 8, 15 and 22 of radiation. The study endpoints were treatment-related toxicities which were graded according to CTCAE version 5.0.Results:One hundred and thirteen patients were analysed for the study. Gastrointestinal toxicity was the predominant toxicity observed followed by haematological toxicity. 31·7% patients reported grade 1–2 diarrhoea and 39·7% reported grade 1–2 leucopenia. None of the patients reported grade 3 or higher toxicities. Treatment interruptions were noted due to these toxicities.Conclusion:Concurrent chemoradiation is the definitive treatment for locally advanced carcinoma cervix with acceptable toxicities. Proper management measures should be undertaken for these toxicities to avoid treatment interruptions and ensure better treatment compliance.
Impact of intra-fractional motion on dose distributions in lung IMRT
Authors: Chetvertkov Mikhail A. , Vassiliev Oleg N. , Yang Jinzhong , Wang He C. , Liu Amy Y. , Liao Zhongxing , Mohan Radhe 
Published: January 2020

AbstractAim:To investigate the impact of intra-fractional motion on dose distribution in patients treated with intensity-modulated radiotherapy (IMRT) for lung cancer.Materials and methods:Twenty patients who had undergone IMRT for non-small cell lung cancer were selected for this retrospective study. For each patient, a four-dimensional computed tomography (CT) image set was acquired and clinical treatment plans were developed using the average CT. Dose distributions were then recalculated for each of the 10 phases of respiratory cycle and combined using deformable image registration to produce cumulative dose distributions that were compared with the clinical treatment plans.Results:Intra-fractional motion reduced planning target volume (PTV) coverage in all patients. The median reduction of PTV covered by the prescription isodose was 3·4%; D98 was reduced by 3·1 Gy. Changes in the mean lung dose were within ±0·7 Gy. V20 for the lung increased in most patients; the median increase was 1·6%. The dose to the spinal cord was unaffected by intra-fractional motion. The dose to the heart was slightly reduced in most patients. The median reduction in the mean heart dose was 0·22 Gy, and V30 was reduced by 2·5%. The maximum dose to the oesophagus was also reduced in most patients, by 0·74 Gy, whereas V50 did not change significantly. The median number of points in which dose differences exceeded 3%/3 mm was 6·2%.Findings:Intra-fractional anatomical changes reduce PTV coverage compared to the coverage predicted by clinical treatment planning systems that use the average CT for dose calculation. Doses to organs at risk were mostly over-predicted.
HO Generation Above Sprite‐Producing Thunderstorms Derived from Low‐Noise SMILES Observation Spectra
Authors: Yamada T. , Sato T. O. , Adachi T. , Winkler H. , Kuribayashi K. , Larsson R. , Yoshida N. , Takahashi Y. , Sato M. , Chen A. B. , Hsu R. R. , Nakano Y. , Fujinawa T. , Nara S. , Uchiyama Y. , Kasai Y. 
Published: January 2020

AbstractNo direct observational evidence of sprite‐produced active radicals has been presented owing to the difficulty of observing a small event area in the nighttime mesosphere, whereas sprite chemical models have indicated that sprite discharge locally affects the atmospheric composition. We present the first observational evidence of a HOproduction above sprite‐producing thunderstorms from the coincidence of temporal‐spatial observations of HOspectra, sprite events, and thunderstorms by two space instruments, a submillimeter‐wave limb spectrometer and ultraviolet/visible Imager and a ground‐based very low frequency radiation lightning detection network. A total of three areas was identified with enhanced HOlevels of approximately 10molecules. A chemical sprite model indicates an increase in HOin the considered altitude region; however, the predicted production due to a single sprite event is smaller than the observed enhancement. Our observational results suggest that sprites potentially contribute 1% of nighttime background HOgeneration at altitudes of 75–80 km globally.
Sugar, Gravel, Fish, and Flowers: Dependence of Mesoscale Patterns of Trade‐Wind Clouds on Environmental Conditions
Authors: Bony Sandrine , Schulz Hauke , Vial Jessica , Stevens Bjorn 
Published: January 2020

AbstractTrade‐wind clouds exhibit a large diversity of spatial organizations at the mesoscale. Over the tropical western Atlantic, a recent study has visually identified four prominent mesoscale patterns of shallow convection, referred to as flowers, fish, gravel, and sugar. We show that these four patterns can be identified objectively from satellite observations by analyzing the spatial distribution of infrared brightness temperatures. By applying this analysis to 19 years of data, we examine relationships between cloud patterns and large‐scale environmental conditions. This investigation reveals that on daily and interannual timescales, the near‐surface wind speed and the strength of the lower‐tropospheric stability discriminate the occurrence of the different organization patterns. These results, combined with the tight relationship between cloud patterns, low‐level cloud amount, and cloud‐radiative effects, suggest that the mesoscale organization of shallow clouds might change under global warming. The role of shallow convective organization in determining low‐cloud feedback should thus be investigated.
Ion Cyclotron Resonant Absorption Lines in ELF Hiss Power Spectral Density in the Low‐Latitude Ionosphere
Authors: Chen Lunjin , Pfaff Robert , Heelis Roderick , Boardsen Scott , Xia Zhiyang 
Published: January 2020

AbstractThe effects of multiple ion species have been observed in electromagnetic wave spectra in both the ionosphere and the magnetosphere. Here we report an event from Communication/Navigation Outage Forecast System satellite, showing a new imprint of various ion species in observations of extremely low frequency (ELF) hiss wave spectra near the equatorial ionosphere, which presents minima in the power spectral density at gyrofrequencies and their harmonics of multiple ion species (e.g., O
and He
). Cyclotron harmonic resonant absorption is proposed to account for the observed spectral and polarization properties. Furthermore, the implication of using those wave power spectral minima to identify minor ion species in the ionosphere is discussed.
Clustering of Floating Tracer Due to Mesoscale Vortex and Submesoscale Fields
Authors: Stepanov Dmitry V. , Ryzhov Eugene A. , Zagumennov Alexei A. , Berloff Pavel , Koshel Konstantin V. 
Published: January 2020

AbstractFloating tracer clustering is studied in oceanic flows that combine both a field of coherent mesoscale vortices, as simulated by a regional, comprehensive, eddy‐resolving general circulation model, and kinematic random submesoscale velocity fields. Both fields have rotational and divergent velocity components, and depending on their relative contributions, as well as on the local characteristics of the mesoscale vortices, we identified different clustering scenarios. We found that the mesoscale vortices do not prevent clustering but significantly modify its rate and spatial pattern. We also demonstrated that even weak surface‐velocity divergence has to be taken into account to avoid significant errors in model predictions of the floating tracer patterns. Our approach combining dynamically constrained and random velocity fields, and the applied diagnostic methods, are proposed as standard tools for analyses and predictions of floating tracer distributions, in both observational data and general circulation models.
Arctic Ocean Precipitation From Atmospheric Reanalyses and Comparisons With North Pole Drifting Station Records
Authors: Barrett Andrew P. , Stroeve Julienne C. , Serreze Mark C. 
Published: January 2020

AbstractWe evaluate fields of Arctic Ocean precipitation from six atmospheric reanalyses: NASA MERRA, NASA MERRA2, NOAA CFSR/CFSv2, ECMWF ERA‐Interim, ECMWF ERA5, and JMAO JRA55. The study is motivated by recognition that precipitation fields from reanalyses can serve as the key input into snow on sea ice accumulation models, supporting retrievals of sea ice thickness from satellite altimeter systems. Time series of annual precipitation over the central Arctic Ocean correlate well between all reanalyses, and they all capture the basic spatial and seasonal patterns of Arctic precipitation. However, they differ strongly with respect to precipitation amount: CFSR and MERRA2 are wetter than the other reanalyses. All reanalyses depict that the majority of total annual precipitation over the central Arctic Ocean comes from small events, less than 1 mm/day. Validation is challenged by sparse observations, uncertain adjustments for gauge undercatch, and other issues. However, given that correlations with data from Russian North Pole drifting station records are all roughly equal and that they depict similar interannual variability at the regional scale, all of the reanalyses appear suitable for supporting retrievals of ice thickness (provided that appropriate bias corrections can be applied). However, only CFSR, MERRA2, ERA5, and JRA55 will continue to generate output beyond 2019.
Shelf‐Break Upwelling and Productivity Over the North Kenya Banks: The Importance of Large‐Scale Ocean Dynamics
Authors: Jacobs Z. L. , Jebri F. , Raitsos D. E. , Popova E. , Srokosz M. , Painter S. C. , Nencioli F. , Roberts M. , Kamau J. , Palmer M. , Wihsgott J. 
Published: January 2020

AbstractThe North Kenya Banks (NKBs) have recently emerged as a new frontier for food security and could become an economically important fishery for Kenya with improved resources providing better accessibility. Little research has been done on the mechanisms supporting high fish productivity over the NKBs with information on annual and interannual environmental variability lacking. Here we use a high‐resolution, global, biogeochemical ocean model with remote sensing observations to demonstrate that the ocean circulation exerts an important control on the productivity over the NKBs. During the Northeast Monsoon, which occurs from December to February, upwelling occurs along the Kenyan coast, which is topographically enhanced over the NKBs. Additionally, enhanced upwelling events, associated with widespread cool temperatures, elevated chlorophyll, nutrients, primary production, and phytoplankton biomass, can occur over this region. Eight such modeled events, characterized by primary production exceeding 1.3 g C/m−2/day, were found to occur during January or February from 1993–2015. Even though the upwelling is always rooted to the NKBs, the position, spatial extent, and intensity of the upwelling exhibit considerable interannual variability. The confluence zone between the Somali Current and East African Coastal Current (referred to as the Somali‐Zanzibar Confluence Zone) forms during the Northeast Monsoon and is highly variable. We present evidence that when the Somali‐Zanzibar Confluence Zone is positioned further south, it acts to enhance shelf‐edge upwelling and productivity over the NKBs. These findings provide the first indication of the environmental controls that need to be considered when developing plans for the sustainable exploitation of the NKB fishery.
Electrical Resistivity of Freezing Clay: Experimental Study and Theoretical Model
Authors: Ming F. , Li D. Q. , Chen L. 
Published: January 2020

AbstractElectrical resistivity of soil has become one of the most important indicators of compactness and compressive resistance. In previous studies, the temperature of soil tested was always above 0 °C. However, due to the phase change of pore water, the resistivity of freezing soils is different from that of unfrozen soils. Therefore, it is necessary to clarify the influence of temperature on electrical resistivity. To achieve this goal, according to the bundle of the cylindrical capillary model, pores in soil were treated as conducting tubes, and two simple lognormal functions were introduced to describe the distribution of the conducting tubes. Based on the conductivity theory, a new model considering the temperature and the pore size distribution was presented. Results show that only a part of the conducting tubes can be treated as the effective conducting tubes, which are determined by the soil temperature. Furthermore, a small portion of the pores with the smaller size controlled the electrical resistivity of the freezing clay. In other words, the change in the electrical resistivity of freezing clay was caused mainly by the change of unfrozen water content through the decrease in temperature. Based on the experimental results conducted on clay from Northeast China, the validity of the presented model was verified. The comparison results indicate that there was a good agreement between the calculated results and the experimental results. To expand the scope of the model, more laboratory tests are suggested to conduct to verify the applicability of the model to other clays.