bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of tropospheric NO2 columns from MAX-DOAS retrievals and regional air quality model simulations
Authors: Blechschmidt Anne-Marlene , Arteta Joaquim , Coman Adriana , Curier Lyana , Eskes Henk , Foret Gilles , Gielen Clio , Hendrick Francois , Marécal Virginie , Meleux Frédérik , Parmentier Jonathan , Peters Enno , Pinardi Gaia , Piters Ankie J. M. , Plu Matthieu , Richter Andreas , Sofiev Mikhail , Valdebenito Álvaro M. , Van Roozendael Michel , Vira Julius , Vlemmix Tim , Burrows John P.
Published: March 2017

Abstract. Tropospheric NO2 is hazardous to human health and can lead to tropospheric ozone formation, eutrophication of ecosystems and acid rain production. It is therefore important to establish accurate data based on models and observations to understand and monitor tropospheric NO2 concentrations on a regional and global scale. In the present study, MAX-DOAS tropospheric NO2 column retrievals from four European measurement stations are compared to regional model ensemble simulations. The latter are based on regional air quality models which contribute to the European regional ensemble forecasts and reanalyses of the operational Copernicus Atmosphere Monitoring Service (CAMS). Compared to other observational data usually applied for regional model validation, MAX-DOAS data is closer to the regional model data in terms of horizontal and vertical resolution and measurements are available during daylight. In general, there is a good agreement between simulated and retrieved NO2 column values for individual MAX-DOAS measurements with correlations between 45 and 75 % for tropospheric NO2 VCDs, indicating that the model ensemble represents the emission and tropospheric chemistry of NOx (NO + NO2) well. Pollution transport towards the stations is on average well represented by the models. However, large differences are found for individual pollution plumes. Seasonal cycles are overestimated, weekly cycles are reproduced well and diurnal cycles poorly represented by the model ensemble. In particular, simulated morning rush hour peaks are not confirmed by MAX-DOAS retrievals. Our results demonstrate that a large number of validation points are available from MAX-DOAS measurements, which should therefore be used more extensively in future regional air quality modelling studies.
The impact of aged wildfire smoke on atmospheric composition and ozone in the Colorado Front Range in summer 2015
Authors: Lindaas Jakob , Farmer Delphine K. , Pollack Ilana B. , Abeleira Andrew , Flocke Frank , Roscioli Rob , Herndon Scott , Fischer Emily V.
Published: March 2017

Abstract. The relative importance of wildfire smoke for air quality over the western U.S. is expected to increase as the climate warms and anthropogenic emissions decline. We report on in situ measurements of ozone (O3), a suite of volatile organic compounds (VOCs), and reactive oxidized nitrogen species collected during summer 2015 at the Boulder Atmospheric Observatory (BAO) in Erie, CO. Aged wildfire smoke impacted BAO during two distinct time periods during summer 2015: 6–10 July and 16–30 August. The smoke was transported from the Pacific Northwest and Canada across much of the continental U.S. Carbon monoxide and particulate matter increased during the smoke-impacted periods, along with peroxyacyl nitrates and several VOCs that have atmospheric lifetimes longer than the transport timescale of the smoke. During the August smoke-impacted period, nitrogen dioxide was also elevated during the morning and evening compared to the smoke-free periods. There were six days during our study period where the maximum 8-hour average O3 at BAO was greater than 65 ppbv, and two of these days were smoke-impacted. We examined the relationship between O3 and temperature at BAO and found that for a given temperature, O3 mixing ratios were greater (~ 10 ppbv) during the smoke-impacted periods. Enhancements in O3 during the August smoke-impacted period were also observed at two long-term monitoring sites in Colorado: Rocky Mountain National Park and the Arapahoe National Wildlife Refuge near Walden, CO. Our data provide a new case study of how aged wildfire smoke can influence atmospheric composition at an urban site, and how smoke can contribute to increased O3 abundances across an urban-rural gradient.
Multi-species inversion and IAGOS airborne data for a better constraint of continental scale fluxes
Authors: Boschetti Fabio , Thouret Valerie , Maenhout Greet Janssens , Totsche Kai Uwe , Marshall Julia , Gerbig Christoph
Published: March 2017

Abstract. Airborne measurements of CO2, CO, and CH4 proposed in the context of IAGOS (In-service Aircraft for a Global Observing System) will provide profiles from take-off and landing of airliners in the vicinity of major metropolitan areas useful for constraining sources and sinks. A proposed improvement of the top-down method to constrain sources and sinks is the use of a multispecies inversion. Different species such as CO2 and CO have partially overlapping emission patterns for given fuel-combustion related sectors, and thus share part of the uncertainties, both related to the a priori knowledge of emissions, and to model-data mismatch error. We use a regional modeling framework consisting of the Lagrangian particle dispersion model STILT (Stochastic Time-Inverted Lagrangian Transport), combined with high resolution (10 km × 10 km) EDGARv4.3 (Emission Database for Global Atmospheric Research) emission inventory, differentiated by emission sector and fuel type for CO2, CO, and CH4, and combined with the VPRM (Vegetation Photosynthesis and Respiration Model) for biospheric fluxes of CO2. Applying the modeling framework to synthetic IAGOS profile observations, we evaluate the benefits of using correlations between different species’ uncertainties on the performance of the atmospheric inversion. The available IAGOS CO observations are used to validate the modeling framework. Prior uncertainty values are conservatively assumed to be 20 %, for CO2 and 50 % for CO and CH4, while those for, GEE (Gross Ecosystem Exchange) and respiration are derived from existing literature. Uncertainty reduction for different species is evaluated on a domain encircling 50 % of the profile observations’ surface influence over Europe. We found that our modeling framework reproduces the CO observations with an average correlation of 0.56, but simulates lower mixing ratios by a factor 2.8, reflecting a low bias in the emission inventory. Mean uncertainty reduction achieved for CO2 fossil fuel emissions is roughly 37 %; for photosynthesis and respiration flux it is 41 % and 45 %, respectively. For CO and CH4 the uncertainty reduction is roughly 63 % and 67 %, respectively. Considering correlation between different species, posterior uncertainty can be reduced by up to 23 %; such reduction depends on the assumed error structure of the prior and on the considered timeframe. The study suggests a significant uncertainty constraint on regional emissions using multi-species inversions of IAGOS in situ observations.
Sensitivities of Amazonian clouds to aerosols and updraft speed
Authors: Cecchini Micael A. , Machado Luiz A. T. , Andreae Meinrat O. , Martin Scot T. , Albrecht Rachel I. , Artaxo Paulo , Barbosa Henrique M. J. , Borrmann Stephan , Fütterer Daniel , Jurkat Tina , Mahnke Christoph , Minikin Andreas , Molleker Sergej , Pöhlker Mira L. , Pöschl Ulrich , Rosenfeld Daniel , Voigt Christiane , Wenzierl Bernadett , Wendisch Manfred
Published: March 2017

Abstract. The effects of aerosol particles and updraft speed on warm-phase cloud microphysical properties are studied in the Amazon region as part of the ACRIDICON-CHUVA experiment. Here we expand the sensitivity analysis usually found in the literature by concomitantly considering cloud evolution, putting the sensitivity quantifications into perspective in relation to in-cloud processing, and by considering the effects on droplet size distribution (DSD) shape. Our in-situ aircraft measurements over the Amazon basin cover a wide range of particle concentration and thermodynamic conditions, from the pristine regions over coastal and forested areas to the highly biomass-burning-polluted southern Amazon. The quantitative results show that particle concentration is the primary driver for the vertical profiles of effective diameter and droplet concentration in the warm phase of Amazonian convective clouds, while updraft speeds have a modulating role in the latter and in total condensed water. The cloud microphysical properties were found to be highly variable with altitude above cloud base, which we used as a proxy for cloud evolution since it is a measure of the time droplets were subject to cloud processing. We show that DSD shape is crucial in understanding cloud sensitivities. The aerosol effect on DSD shape was found to vary with altitude, which can help models to better constrain the indirect aerosol effect on climate.
Single particle measurements of bouncing particles and in-situ collection efficiency from an airborne aerosol mass spectrometer (AMS) with light scattering
detection
Authors: Liao Jin , Brock Charles A. , Murphy Daniel M. , Sueper Donna T. , Welti André , Middlebrook Ann M.
Published: March 2017

Abstract. A light scattering module was coupled to an airborne, compact time-of-flight aerosol mass spectrometer (LS-ToF-AMS) to investigate collection efficiency (CE) while obtaining non-refractory aerosol chemical composition measurements during the Southeast Nexus (SENEX) campaign. In this instrument, particles typically larger than ~ 250 nm in vacuum aerodynamic diameter scatter light from an internal laser beam and trigger saving individual particle mass spectra. Over 33,000 particles are characterized as either prompt (27 %), delayed (15 %), or null (58 %), according to the appearance time and intensity of their mass spectral signals. The individual particle mass from the spectra is proportional to the mass derived from the vacuum aerodynamic diameter determined by the light scattering signals (dva-LS) rather than the traditional particle time-of-flight (PToF) size (dva). The delayed particles capture about 80 % of the total chemical mass compared to prompt ones. Both field and laboratory data indicate that the relative intensities of various ions in the prompt spectra show more fragmentation compared to the delayed spectra. The particles with a delayed mass spectral signal likely bounced on the vaporizer and vaporized later on a lower temperature surface within the confines of the ionization source. Because delayed particles are detected at a later time by the mass spectrometer than expected, they can affect the interpretation of PToF mass distributions especially at the larger sizes. CE, measured by the average number or mass fractions of particles optically detected that have measureable mass spectra, varied significantly (0.2–0.9) in different air masses. Relatively higher null fractions and corresponding lower CE for this study may have been related to the lower sensitivity of the AMS during SENEX. The measured CE generally agreed with the CE parameterization based on ambient chemical composition, including for acidic particles that had a higher CE as expected from previous studies.
Error estimate of Taylor's frozen-in flow hypothesis in the spectral domain
Authors: Narita Yasuhito
Published: March 2017

Abstract. The quality of Taylor's frozen-in flow hypothesis can be measured by estimating the amount of the fluctuation energy mapped from the streamwise wavenumbers onto the Doppler-shifted frequencies in the spectral domain. For a random sweeping case with a Gaussian variation of the large-scale flow, the mapping quality is expressed by the error function which depends on the mean flow speed, the sweeping velocity, the frequency bin, and the frequency of interest. Both hydrodynamic and magnetohydrodynamic treatments are presented on the error estimate of Taylor's hypothesis with examples from the solar wind measurements.
Manganese and iron reduction dominate organic carbon oxidation in surface sediments of the deep Ulleung Basin, East Sea
Authors: Hyun Jung-Ho , Kim Sung-Han , Mok Jin-Sook , Cho Hyeyoun , Lee Tongsup , Vandieken Verona , Thamdrup Bo
Published: March 2017

Abstract. Rates and pathways of benthic organic carbon (Corg) oxidation were investigated in surface sediments of the Ulleung Basin (UB) characterized by high Corg contents ( >  2.5 %, dry wt.) and very high contents of Mn oxides ( >  200 µmol cm−3) and Fe oxides (up to 100 µmol cm−3). The combination of geochemical analyses and independently executed metabolic rate measurements revealed that Mn and Fe reduction were the dominant Corg oxidation pathways in the center of the UB, comprising 45 and 20 % of total Corg oxidation, respectively. By contrast, sulfate reduction was the dominant Corg oxidation pathway, accounting for 50 % of total Corg mineralization in sediments of the continental slope. The relative significance of each Corg oxidation pathway matched the depth distribution of the respective electron acceptors. The relative importance of Mn reduction for Corg oxidation displays saturation kinetics with respect to Mn oxide content with a low half-saturation value of 8.6 µmol cm−3, which further implies that Mn reduction can be a dominant Corg oxidation process even in sediments with lower MnO2 content as known from several other locations. This is the first report of a high contribution of manganese reduction to Corg oxidation in offshore sediments on the Asian margin. The high manganese oxide content in the surface sediment in the central UB was maintained by an extreme degree of recycling, with each Mn atom on average being reoxidized ∼ 3800 times before permanent burial. This is the highest degree of recycling so far reported for Mn-rich sediments, and it appears linked to the high benthic mineralization rates resulting from the high Corg content that indicate the UB as a biogeochemical hotspot for turnover of organic matter and nutrient regeneration.
Daily variation in net primary production and net calcification in coral reef communities exposed to elevated pCO2
Authors: Comeau Steeve , Edmunds Peter J. , Lantz Coulson A. , Carpenter Robert C.
Published: March 2017

Abstract. The threat represented by ocean acidification (OA) for coral reef has received considerable attention because of the sensitivity of calcifiers to changing water carbonate chemistry. However most studies have focused on the organismic response of calcification to OA, and only a few have addressed community-level effects, or investigated parameters other than calcification, such as photosynthesis. Light (Photosynthetically Active Radiation, PAR) is a driver of biological processes on coral reefs, and the possibility that these processes might be perturbed by OA has important implications for community function. Here we investigate how CO2 enrichment affects the relationships between PAR and community net O2 production (Pnet), and between PAR and community net calcification (Gnet), using experiments on three coral communities constructed to match (i) the back reef of Moorea, French Polynesia, (ii) the fore reef of Moorea, and (iii) the reef flat of Oahu, Hawaii. The results were used to test the hypothesis that OA affects the relationship between Pnet and Gnet. For the three communities tested, pCO2 did not affect the Pnet-PAR relationship, but it affected the intercept of the hyperbolic tangent curve fitting the Gnet-PAR relationship for both reef communities in Moorea (but not in Oahu). For the three communities, the slopes of the linear relationships between Pnet and Gnet were not affected by OA, although the intercepts were depressed by the inhibitory effect of high pCO2 on Gnet. Our result indicates that OA can modify the balance between net calcification and net photosynthesis of reef communities by depressing community calcification, but without affecting community photosynthesis.
A case study of rainfall-derived infiltration and inflow on a separate sanitary sewer system
Authors: Carriço Nelson J. G. , Brito Rita , Baptista Manuel
Published: March 2017

Abstract. Rainfall-derived infiltration and inflow (RDII) can interfere with the performance of domestic wastewater drainage systems. It is also a major cause for the deterioration of the functional performance in those systems and for the occurrence of domestic wastewater untreated discharges to the water environment. In most cases, the actual size and location of these inflows are unknown. To assess this subject of RDII, a detailed knowledge of the network is required as well as a diagnosis of the problem, namely, the type of inflows, the magnitude of their occurrence and the location of the most relevant impacts. This paper presents the application of a methodology to estimate RDII on a Portuguese case study.
Picturing and modeling catchments by representative hillslopes
Authors: Loritz Ralf , Hassler Sibylle K. , Jackisch Conrad , Allroggen Niklas , van Schaik Loes , Wienhöfer Jan , Zehe Erwin
Published: March 2017

Abstract. This study explores the suitability of a single hillslope as a parsimonious representation of a catchment in a physically based model. We test this hypothesis by picturing two distinctly different catchments in perceptual models and translating these pictures into parametric setups of 2-D physically based hillslope models. The model parametrizations are based on a comprehensive field data set, expert knowledge and process-based reasoning. Evaluation against streamflow data highlights that both models predicted the annual pattern of streamflow generation as well as the hydrographs acceptably. However, a look beyond performance measures revealed deficiencies in streamflow simulations during the summer season and during individual rainfall–runoff events as well as a mismatch between observed and simulated soil water dynamics. Some of these shortcomings can be related to our perception of the systems and to the chosen hydrological model, while others point to limitations of the representative hillslope concept itself. Nevertheless, our results confirm that representative hillslope models are a suitable tool to assess the importance of different data sources as well as to challenge our perception of the dominant hydrological processes we want to represent therein. Consequently, these models are a promising step forward in the search for the optimal representation of catchments in physically based models.
Spontaneous lung pathology in a captive common marmoset colony (Callithrix jacchus)
Authors: Bleyer Martina , Kunze Marius , Gruber-Dujardin Eva , Mätz-Rensing Kerstin
Published: March 2017

Abstract. Data on spontaneous pathology are substantially scarce for common marmosets, compared to other laboratory animals, but is essential for the interpretation of histological findings in the context of toxicological and experimental studies. Especially if common marmosets are used as experimental animals in respiratory research, detailed knowledge on the spectrum, occurrence, and incidence of spontaneous histopathological pulmonary lesions in this non-human primate species is required. In this study, lung tissue of 638 common marmosets from the marmoset colony of the German Primate Center was examined histologically. The analysis revealed a high incidence of predominantly mild and multifocal interstitial pneumonia (32.99 %) of unknown etiology in most cases. Only few marmosets exhibited lobar pneumonia (1.41 %) and bronchopneumonia (0.94), which were mainly caused by bacterial pathogens such as Bordetella bronchiseptica and Klebsiella pneumoniae. Lung immaturity and atelectasis were common histological findings in newborn marmosets. Typical background lesions included anthracosis (8.15 %), hemosiderosis (1.72 %), extramedullary hematopoiesis (11.6 %), mineralization (10.97 %), and inflammatory cell foci (10.34 %). In addition, three cases of pulmonary arteriopathy (0.47 %) and 1 case of foreign-body granuloma (0.16 %) were detected in the marmoset study cohort. The high prevalence of circulatory disturbances (congestion, edema, hemorrhage) and changes in air content (secondary atelectasis, alveolar emphysema) could partly be explained by euthanasia-related artifacts or agonal changes. The present study provides a comprehensive overview of the range and incidence of spontaneous pulmonary histopathology in common marmosets, serving as valuable reference data for the interpretation of lung lesions in toxicological and experimental marmoset studies.
Soil conservation in the 21st century: why we need smart agricultural intensification
Authors: Govers Gerard , Merckx Roel , van Wesemael Bas , Van Oost Kristof
Published: March 2017

Abstract. Soil erosion severely threatens the soil resource and the sustainability of agriculture. After decades of research, this problem still persists, despite the fact that adequate technical solutions now exist for most situations. This begs the question as to why soil conservation is not more rapidly and more generally implemented. Studies show that the implementation of soil conservation measures depends on a multitude of factors but it is also clear that rapid change in agricultural systems only happens when a clear economic incentive is present for the farmer. Conservation measures are often more or less cost-neutral, which explains why they are often less generally adopted than expected. This needs to be accounted for when developing a strategy on how we may achieve effective soil conservation in the Global South, where agriculture will fundamentally change in the next century. In this paper we argue that smart intensification is a necessary component of such a strategy. Smart intensification will not only allow for soil conservation to be made more economical, but will also allow for significant gains to be made in terms of soil organic carbon storage, water efficiency and biodiversity, while at the same time lowering the overall erosion risk. While smart intensification as such will not lead to adequate soil conservation, it will facilitate it and, at the same time, allow for the farmers of the Global South to be offered a more viable future.
Comparison of measurements from different radio-echo sounding systems and synchronization with the ice core at Dome C, Antarctica
Authors: Winter Anna , Steinhage Daniel , Arnold Emily J. , Blankenship Donald D. , Cavitte Marie G. P. , Corr Hugh F. J. , Paden John D. , Urbini Stefano , Young Duncan A. , Eisen Olaf
Published: March 2017

Abstract. We present a compilation of radio-echo sounding (RES) measurements of five radar systems (AWI, BAS, CReSIS, INGV and UTIG) around the EPICA Dome C (EDC) drill site, East Antarctica. The aim of our study is to investigate the differences of the various systems in their resolution of internal reflection horizons (IRHs) and bed topography, penetration depth and capacity of imaging the basal layer. We address the questions of the compatibility of existing radar data for common interpretation and the suitability of the individual systems for reconnaissance surveys. We find that the most distinct IRHs and IRH patterns can be identified and transferred between most data sets. Considerable differences between the RES systems exist in range resolution and depiction of the bottom-most region. Considering both aspects, which we judge as crucial factors in the search for old ice, the CReSIS and the UTIG systems are the most suitable ones. In addition to the RES data set comparison we calculate a synthetic radar trace from EDC density and conductivity profiles. We identify 10 common IRHs in the measured RES data and the synthetic trace. We then conduct a sensitivity study for which we remove certain peaks from the input conductivity profile. As a result the respective reflections disappear from the modeled radar trace. In this way, we establish a depth conversion of the measured travel times of the IRHs. Furthermore, we use these sensitivity studies to investigate the cause of observed reflections. The identified IRHs are assigned ages from the EDC's timescale. Due to the isochronous character of these conductivity-caused IRHs, they are a means to extend the Dome C age structure by tracing the IRHs along the RES profiles.
Estilo de liderazgo en profesionales de enfermería según su función en los sectores público o privado en Temuco, Chile, 2015
Authors: Cárcamo-Fuentes Claudio , Rivas-Riveros Edith
Published: March 2017

Introducción: el liderazgo de enfermería se considera una competencia fundamental, por su clara repercusión en la calidad de los cuidados. Objetivo: conocer el estilo de liderazgo que ejercen enfermeras(os) asistenciales, docentes y supervisoras(es). Material y método: investigación cuantitativa, descriptiva y transversal. La muestra está constituida por 165 profesionales de enfermería del área adulto-pediátrica, en una ciudad del sur de Chile. La recolección de datos se realizó mediante el Cuestionario Multifactorial de Liderazgo, en su forma corta, adaptado a la población chilena por Vega y Zabala. Resultados: se evidencia que los profesionales en enfermería asistenciales desarrollan en menor grado los estilos transformacional y transaccional. Por el contrario, aquellos de las áreas docente y de supervisión utilizan preferentemente un liderazgo transaccional, donde se destaca la recompensa contingente en docentes y la consideración individualizada en supervisores, como las principales. Según el sexo, las mujeres utilizan con mayor frecuencia las conductas motivación inspiracional y carisma inspiracional. Además, el liderazgo transaccional está más presente en mujeres, al igual que la consideración individualizada. Conclusión: se aprecia el predominio del liderazgo transaccional en enfermeras(os) docentes y supervisoras(es), que afecta el desarrollo y el fortalecimiento de un liderazgo transformador esencial para una gestión del cuidado de calidad.
Event Study on the Reaction of Stock Returns to Acquisition News
Authors: Elad Fotoh Lazarus , Bongbee Nko Solange
Published: March 2017

This study examines the reaction of stock returns to acquisition news. A data of 51 observations of acquiring companies with publicly traded shares on the London Stock Exchange (FTSE100) is used over a period, from July 2012 to May 2013 with an estimation period [-100, -10] and test period [-5, +5]. The market model is applied here in order to predict future stock returns and the use of the simple regression to get the parameters of the regression equation. With this a test statistics obtained on average, is significantly positive and greater than the critical value. Therefore, the event of acquisition does appear to be related significantly to the abnormal returns and the null hypothesis being rejected.
Do Real Depreciations Reduce the Income Gap between the Rich and the Poor?
Authors: Qu Guangjun
Published: March 2017

This study concentrates on the effect of real depreciations of a currency on one key aspect of economic development, the distribution of income. Based upon the recent availability of a real depreciation index and two databases on Gini coefficients, we investigate how real depreciations affect levels and changes in the distribution of income. The panel evidence of more than  158 countries indicates that real depreciations are associated with a decline in levels of income gap between the rich and the poor. They, however, have no statistically significant association with changes in the distribution of income. Therefore, the relationship between real depreciations and levels of the distribution of income is likely to stem from reverse causality. Our main findings may help policymakers who attempt to use a currency depreciation policy fully realize that the policy at least does not hurt the poor.
A retrorectal epidermoid cyst as the cause of recurrent anal fistula – a case report
Authors: Talarek Michał , Kucharczyk Agnieszka
Published: March 2017

Inflammation of the anal crypt is the most common cause of anal fistula. Other causesof anal fistula include Crohn’s disease, injury (including iatrogenic), a foreign bodyand casuistic causes, such as tuberculosis, actinomycosis, etc. We present a case ofa patient receiving unsuccessful conservative and surgical treatment due to recurrent anal fistula caused by a congenital retrorectal epidermoid cyst. Extracutaneousepidermoid cyst is a rare pathology and a congenital defect. It develops between 4 and8 weeks’ gestation due to impaired ectodermal development. A complete resectionof the lesion following an accurate imaging diagnosis (transrectal ultrasonography or magnetic resonance) is the treatment of choice in symptomatic retrorectal epidermoid cyst. In the presented case, the patient underwent, following a diagnostic process, a surgery involving a complete resection of the fistula tract along with a groupof small cysts. During the surgery, no connection was found between the lesions andthe anus or the anal sphincters. The postoperative site extending above the analsphincters was allowed to heal by secondary intention. The patient was dischargedhome on day 3 post surgery. The wound healed after 12 weeks.Conclusions. Aetiology other than the anal crypt should be considered and an accurate preoperative diagnosis aimed to determine the cause of fistula and chooseappropriate therapeutic management should be established in the case of recurrentanal fistula and atypical course of disease.
Quantitative Analysis of Aloins and Aloin-Emodin in Aloe Vera Raw Materials and Finished Products Using High-Performance Liquid Chromatography: Single-Laboratory Validation, First Action 2016.09
Authors: Kline David , Ritruthai Vicha , Babajanian Silva , Gao Quanyin , Ingle Prashant , Chang Peter , Swanson Gary
Published: March 2017

A single-laboratory validation study is described for a method of quantitative analysis of aloins (aloins Aand B) and aloe-emodin in aloe vera raw materials and finished products. This method used HPLC coupled with UVdetection at 380 nm for the aloins and 430 nm for aloe-emodin. The advantage of this test method is that the target analytes are concentrated from the sample matrix (either liquid or solid form) using stepwise liquid–liquid extraction (water–ethyl acetate–methanol), followed by solvent evaporation and reconstitution. This sample preparation process is suitable for different forms of products. The concentrating step for aloins and aloe-emodin has enhanced the method quantitation level to 20 parts per billion (ppb). Reversed-phase chromatography using a 250 × 4.6 mm column under gradient elution conditions was used. Mobile phase A is 0.1% acetic acid in water and mobile phase B is 0.1% acetic acid in acetonitrile. The HPLC run starts with a 20% mobile phase B that reaches 35% at 13 min. From 13 to 30 min, mobile phase B is increased from 35 to 100%. From 30 to 40 min, mobile phase B is changed from 100% back to the initial condition of 20% for re-equilibration. The flow rate is 1 mL/min, with a 100 μL injection volume. Baseline separation (Rs > 2.0) for aloins A and B and aloe-emodin was observed under this chromatographic condition. This test method was validated with raw materials of aloe vera 5× (liquid) and aloe vera 200× (powder) and finished products of aloe concentrate (liquid) and aloe (powder). The linearity of the method was studied from10 to 500 ppb for aloins A and B and aloe-emodin, with correlation coefficients of 0.999964, 0.999957, and0.999980, respectively. The test method was proven to be specific, precise, accurate, rugged, and suitable forthe intended quantitative analysis of aloins and aloe-emodin in raw materials and finished products. The S/N for aloins A and B and aloe-emodin at 10 ppb level were 12, 10, and 8, respectively, indicating our conservative LOD level at 10 ppb (the typical LOD level S/N is about 3). The S/N for aloins A and B and aloe-emodin at the 20ppb level were 17, 14, and 16, respectively, indicating our conservative LOQ level at 20 ppb (the typicalLOQ level S/N is about 10). The stock standard solution of a mixture of aloins and aloe-emodin and a working standard solution were found to be stable for at least 19 days when stored refrigerated at 2–8°C, witha recovery of 100 ± 5%.
The Internationalization of the Academic Library: A Systematic Review of 25 Years of Literature on International Students
Authors: Click Amanda B. , Wiley Claire Walker , Houlihan Meggan
Published: March 2017

This study is a systematic review of the library and information science (LIS) literature related to international students and academic libraries. A systematic review involves the methodical collection and analysis of a body of literature and is growing in popularity in the LIS field. Three well-known LIS databases were systematically searched for articles related to the topic, and manual bibliography searches were conducted to find additional publications. Journal articles, book chapters, and conference papers were included or excluded based on established criteria. Findings show that articles published about international students and academic libraries have increased steadily between 1990 and 2014. The majority of authors are affiliated with universities and institutions in the United States, although an increase in represented countries is apparent. Fewer than half of the articles can be considered original research, and surveys are the most popular method for data collection. The LIS field—and international students—would benefit from further exploration of this topic, particularly from original research with practical implications.
Comparison of the Impact of Extensive and Intensive Reading Approaches on the Korean EFL Learners’ Reading Rate and Reading Comprehension Development
Authors: Park A Young
Published: March 2017

Extensive Reading (ER) is a reading approach that aims to make covering large amounts of reading material enjoyable for language learners. Many experimental studies have showed the effectiveness of the ER approach on reading fluency, the ability to read words and process text rapidly and accurately. Though revealing, these findings need to be interpreted with caution due to methodological defects in the measurement of reading fluency in these ER studies. This quasi-experimental study compared the effect of the ER approach with that of the conventional Intensive Reading (IR) approach on EFL learners’ reading rate and reading comprehension with regard to leaners’ proficiency level. Over a 12-week timespan, two intact classes of 72 Korean secondary students received either ER (N = 36) or IR (N = 36) instruction, with pre- and post- differences in performance examined with regard to proficiency level.  Results of an ANCOVA revealed that students’ reading rate and comprehension increased significantly more from the ER approach than from the IR approach. That is, students from the ER group significantly increased their reading rate in comparison to the IR group without impairing reading comprehension. More specifically, the ER approach had a greater positive impact on the learners’ reading rate than the IR approach irrespective of participants’ English proficiency level. However, in terms of reading comprehension, the advanced and intermediate level learners benefited more from the ER approach, while the low level learners benefited more from the IR approach.
A Corpus-based Study of EFL Learners’ Errors in IELTS Essay Writing
Authors: Divsar Hoda , Heydari Robab
Published: March 2017

The present study analyzed different types of errors in the EFL learners’ IELTS essays. In order to determine the major types of errors, a corpus of 70 IELTS examinees’ writings were collected, and their errors were extracted and categorized qualitatively. Errors were categorized based on a researcher-developed error-coding scheme into 13 aspects. Based on the descriptive statistical analyses, the frequency of each error type was calculated and the commonest errors committed by the EFL learners in IELTS essays were identified. The results indicated that the two most frequent errors that IELTS candidates committed were related to word choice and verb forms. Based on the research results, pedagogical implications highlight analyzing EFL learners’ writing errors as a useful basis for instructional purposes including creating pedagogical teaching materials that are in line with learners’ linguistic strengths and weaknesses.
The Effect of Dialogue Journal Writing on EFL Learners' Descriptive Writing Performance: A Quantitative Study
Authors: Dabbagh Ali
Published: March 2017

This study sought to evaluate the effect of dialogue journal writing on writing performance as well as its different sub-components, namely content, organization, vocabulary, language use, and mechanics (Following Polio, 2013). Participants were 84 EFL intermediate learners who were selected based on their performance on Oxford Quick Placement Test (2004) and divided randomly into experimental and control groups. While the participants in the control group took part in descriptive writing pre and post-tests only, their counterparts in experimental group were asked to write 3 journals a week for about 6 months in the period between the pre- and post-tests. The instructor of the experimental group provided feedback to each journal entry mostly on its content and message to which the participants replied in a dialogic manner. Results of independent sample t-test located a significant difference between the experimental and control group regarding the overall writing performance, as well as the sub-components of content, organization, and vocabulary in the post-test. However, the obtained results did not reveal a significant effect of dialogue journal writing on language use and mechanics of writing performance. The results which promise implications for writing instructors, curriculum developers, and material designers are fully discussed.
Indomethacin reproducibly induces metamorphosis inCassiopea xamachanascyphistomae
Authors: Cabrales-Arellano Patricia , Islas-Flores Tania , Thomé Patricia E. , Villanueva Marco A.
Published: March 2017

Cassiopea xamachanajellyfish are an attractive model system to study metamorphosis and/or cnidarian–dinoflagellate symbiosis due to the ease of cultivation of their planula larvae and scyphistomae through their asexual cycle, in which the latter can bud new larvae and continue the cycle without differentiation into ephyrae. Then, a subsequent induction of metamorphosis and full differentiation into ephyrae is believed to occur when the symbionts are acquired by the scyphistomae. Although strobilation induction and differentiation into ephyrae can be accomplished in various ways, a controlled, reproducible metamorphosis induction has not been reported. Such controlled metamorphosis induction is necessary for an ensured synchronicity and reproducibility of biological, biochemical, and molecular analyses. For this purpose, we tested if differentiation could be pharmacologically stimulated as inAurelia aurita, by the metamorphic inducers thyroxine, KI, NaI, Lugol’s iodine, H2O2, indomethacin, or retinol. We found reproducibly induced strobilation by 50 μM indomethacin after six days of exposure, and 10–25 μM after 7 days. Strobilation under optimal conditions reached 80–100% with subsequent ephyrae release after exposure. Thyroxine yielded inconsistent results as it caused strobilation occasionally, while all other chemicals had no effect. Thus, indomethacin can be used as a convenient tool for assessment of biological phenomena through a controlled metamorphic process inC. xamachanascyphistomae.
Digging deeper: new gene order rearrangements and distinct patterns of codons usage in mitochondrial genomes among shrimps from the Axiidea, Gebiidea and Caridea (Crustacea: Decapoda)
Authors: Tan Mun Hua , Gan Han Ming , Lee Yin Peng , Poore Gary C.B. , Austin Christopher M.
Published: March 2017

Background

Whole mitochondrial DNA is being increasingly utilized for comparative genomic and phylogenetic studies at deep and shallow evolutionary levels for a range of taxonomic groups. Although mitogenome sequences are deposited at an increasing rate into public databases, their taxonomic representation is unequal across major taxonomic groups. In the case of decapod crustaceans, several infraorders, including Axiidea (ghost shrimps, sponge shrimps, and mud lobsters) and Caridea (true shrimps) are still under-represented, limiting comprehensive phylogenetic studies that utilize mitogenomic information.

Methods

Sequence reads from partial genome scans were generated using the Illumina MiSeq platform and mitogenome sequences were assembled from these low coverage reads. In addition to examining phylogenetic relationships within the three infraorders, Axiidea, Gebiidea, and Caridea, we also investigated the diversity and frequency of codon usage bias and mitogenome gene order rearrangements.

Results

We present new mitogenome sequences for five shrimp species from Australia that includes two ghost shrimps,Callianassa ceramicaandTrypaea australiensis, along with three caridean shrimps,Macrobrachium bullatum,Alpheus lobidens, andCaridinacf.nilotica. Strong differences in codon usage were discovered among the three infraorders and significant gene order rearrangements were observed. While the gene order rearrangements are congruent with the inferred phylogenetic relationships and consistent with taxonomic classification, they are unevenly distributed within and among the three infraorders.

Discussion

Our findings suggest potential for mitogenome rearrangements to be useful phylogenetic markers for decapod crustaceans and at the same time raise important questions concerning the drivers of mitogenome evolution in different decapod crustacean lineages.
Effects of root exudates of woody species on the soil anti-erodibility in the rhizosphere in a karst region, China
Authors: Wang Zhen Hong , Fang Hong , Chen Mouhui
Published: March 2017

Introduction

Rhizospheres, the most active interfaces between plants and soils, play a central role in the long-term maintenance of the biosphere. The anti-erodibility of soils (AES) regulated by the root exudates is crucial to the soil stability in the rhizospheres. However, scientists still debate (1) the key organic matter of the root exudates affecting the AES and (2) the interspecific variation of these root exudates.

Methods

We used an incubation of soils to test the effects of the root exudates from eight woody plant species on the change in soil aggregation and identified the organic matter in these root exudates with gas chromatography-mass spectrometry (GC-MS) and biochemical methods. Furthermore, the relationships between the organic matter in the exudates and the AES in the rhizospheres of 34 additional tree species were analyzed.

Results

The water-stable aggregates of the soils incubated with the root exudates increased by 15%–50% on average compared with control samples. The interspecific differences were significant. The root exudates included hundreds of specific organic matter types; hydrocarbon, total sugar, total amino acids, and phenolic compounds were crucial to the AES. These organic matter types could explain approximately 20–75% of the variation in the total effect of the root exudates on the AES, which was quantified based on the aggregate status, degree of aggregation, dispersion ratio, and dispersion coefficient.

Discussion

The effects of the root exudates on the AES and the interspecific variation are as important as that of root density, litters, and vegetation covers. Many studies explored the effects of root density, litters, vegetation covers, and vegetation types on the AES, but little attention has been paid to the effects of the root exudates on the AES. Different plants secrete different relative contents of organic matter resulting in the variation of the effect of the root exudates on the AES. Our study quantified the causal relationships between the root exudates and the AES using modeling experiments in laboratory and field observations and indicated the interspecific variation of the AES and organic matter of the root exudates.

Conclusions

More organic compounds of the exudates related to the AES were recognized in this study. These results enhance the understanding of the soil stability at a slope and can be applied to ecosystem restoration.
Specimen-level phylogenetics in paleontology using the Fossilized Birth-Death model with sampled ancestors
Authors: Cau Andrea
Published: March 2017

Bayesian phylogenetic methods integrating simultaneously morphological and stratigraphic information have been applied increasingly among paleontologists. Most of these studies have used Bayesian methods as an alternative to the widely-used parsimony analysis, to infer macroevolutionary patterns and relationships among species-level or higher taxa. Among recently introduced Bayesian methodologies, the Fossilized Birth-Death (FBD) model allows incorporation of hypotheses on ancestor-descendant relationships in phylogenetic analyses including fossil taxa. Here, the FBD model is used to infer the relationships among an ingroup formed exclusively by fossil individuals, i.e., dipnoan tooth plates from four localities in the Ain el Guettar Formation of Tunisia. Previous analyses of this sample compared the results of phylogenetic analysis using parsimony with stratigraphic methods, inferred a high diversity (five or more genera) in the Ain el Guettar Formation, and interpreted it as an artifact inflated by depositional factors. In the analysis performed here, the uncertainty on the chronostratigraphic relationships among the specimens was included among the prior settings. The results of the analysis confirm the referral of most of the specimens to the taxaAsiatoceratodus,Equinoxiodus, LavocatodusandNeoceratodus, but reject those toCeratodusandFerganoceratodus. The resulting phylogeny constrained the evolution of the Tunisian sample exclusively in the Early Cretaceous, contrasting with the previous scenario inferred by the stratigraphically-calibrated topology resulting from parsimony analysis. The phylogenetic framework also suggests that (1) the sampled localities are laterally equivalent, (2) but three localities are restricted to the youngest part of the section; both results are in agreement with previous stratigraphic analyses of these localities. The FBD model of specimen-level units provides a novel tool for phylogenetic inference among fossils but also for independent tests of stratigraphic scenarios.
Dysphagia with second-generation antipsychotics: A case report and review of the literature
Authors: Crouse Ericka L. , Alastanos Jennifer N. , Bozymski Kevin M. , Toscano Robert A.
Published: March 2017

Background:

All antipsychotics are associated with extrapyramidal symptoms (EPS). These can present as dysphagia, esophageal dysmotility, or aspiration, all of which may not be recognized as EPS.

Case Report:

A 62-year-old with schizophrenia, prescribed olanzapine 5 mg daily, presented agitated and endorsed difficulty swallowing. Speech therapy suggested her complaints were related to either reflux or dysmotility. Esophageal manometry showed her lower esophageal sphincter was not fully relaxing, and identified an esophagogastric junction outflow obstruction. Despite therapeutic dilation, oral intake remained poor. Following an increase in olanzapine, she developed EPS, her dysphagia worsened, and she was choking on food. Following a switch to aripiprazole her EPS and appetite improved, and she ceased complaining of dysphagia.

Discussion:

Dysphagia has been reported with first- and second-generation antipsychotics. A review of the second-generation antipsychotic literature identified case reports of dysphagia with clozapine (n = 5), risperidone (n = 5), olanzapine (n = 2), quetiapine (n = 2), aripiprazole (n = 1), and paliperidone (n = 1). Postulated mechanisms of antipsychotic-induced dysphagia include that it may be an extrapyramidal adverse reaction or related to anticholinergic effects of antipsychotics. Management of dysphagia includes discontinuing the antipsychotic, reducing the dose, dividing the dose, or switching to another antipsychotic. Complications of dysphagia include airway obstruction (eg, choking, asphyxia), aspiration pneumonia, and weight loss. Additional complications include dehydration, malnutrition, and nonadherence to oral medications.

Conclusion:

It is important to recognize symptoms of dysphagia and esophageal dysmotility in antipsychotic-treated patients. Intervention is necessary to prevent complications.