bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chronic fertilization and irrigation gradually and increasingly restructure grassland communities
Authors: Kimmel Kaitlin , Dee Laura , Tilman David , Aubin Isabelle , Boenisch Gerhard , Catford Jane A. , Kattge Jens , Isbell Forest 
Published: March 2019

AbstractScientists have known for over a century that resource addition can lead to species loss from plant communities. Recent studies have also shown that resource addition can substantially restructure communities by altering their functional and taxonomic composition—even when species richness remains unchanged. Understanding which aspects of community structure are impacted by different resources and over which timescales will provide insight for management decisions and may also elucidate which measures can act as early warning indicators for subsequent changes in the community. Here, we take advantage of a long‐term factorial experiment to understand how grassland plant communities respond to a decade of nitrogen fertilization (14 g N·m−2·yr−1) and irrigation (25 mm water/week during the growing season). After 10 yr, fertilization and irrigation decreased species richness by 22% and 9%, while functional richness decreased by 31% and 41%. Abundance‐weighted functional distance between treatments and controls increased by 55% and 24%, respectively. We expected that abundance‐weighted measures would shift before presence–absence‐based measures, but found limited evidence for this. Instead, our results suggest that species gains, which can occur quickly because they require the addition of only one individual, may serve as early indicators for subsequent community restructuring in the opposite direction. Overall, both chronic nitrogen fertilization and irrigation tended to have gradual and increasing impacts on community structure, but the magnitude of these effects varied greatly depending on the aspect of community structure investigated. Further study will be needed to determine the extent to which our results can be generalized to other resources or sites in order to develop management strategies to maintain both taxonomic and functional trait diversity in the face of chronic resource changes.
Stability of native and exotic lady beetle populations in a diverse landscape
Authors: Lamb Robert J. , Bannerman Jordan A. , Costamagna Alejandro C. 
Published: March 2019

AbstractThe stability of populations is a central, yet challenging concept in ecology. Here, we examine the stability of annual abundance for populations of nine native and four exotic lady beetle species (Coccinellidae) in a mixed landscape in Michigan, USA, over 23 yr. The species have similar life histories, live together in the same habitats, and have been disturbed by the sequential introduction of exotic lady beetle species. The publicly available dataset was collected in a diverse landscape of three forest habitats, four annual crop habitats with different intensities of management, and three perennial crops. Replicated 1‐ha plots were sampled weekly with yellow sticky cards during the summer season for each habitat, three plots for each of the three forest types and six plots for each of the seven crop habitats. We quantified stability for each species and each species by habitat combination, using three parameters: trends in abundance, persistence, and temporal population variability. The most abundant lady beetle species were more stable than the uncommon and rare species. Habitat generalists had more stable population dynamics than specialists, but habitat breadth was confounded with lady beetle abundance. Exotic and native species with similar abundances had similar levels of stability. Exotic species disrupted the native populations, leading to declines in abundance for eight of nine species and increased population variability for the native species. The abundances of exotic lady beetles rose quickly to the long‐term mean. Our findings support the hypothesis that populations exhibit species‐specific levels of stability, not greatly affected by stochastic variations in environmental conditions or by habitat characteristics. We also show that exotic species can decrease the stability as well as the abundance of native species in a community of lady beetles.
Photoprotective benefits of pigmentation in the transparent plankton community: a comparative species experimental test
Authors: Bashevkin Samuel M. , Christy John H. , Morgan Steven G. 
Published: March 2019

AbstractPlankton live under the countervailing selective pressures of predation and ultraviolet radiation (UVR). In lakes, zooplankton are transparent reducing visibility to predatory fishes but are pigmented in the absence of fishes, hypothetically reducing UVR damage. In the sea, planktivorous fishes are widespread, so plankton typically are transparent and ascend to productive surface waters at night to forage and descend during the day to reduce visibility to predators. However, larvae of some species face the unique constraint of traveling in surface currents in the daytime during migrations between adult and larval habitats. We would expect these larvae to be transparent since companion studies demonstrated increased predation risk of pigmented larvae under strong sunlight. Paradoxically, larvae range from being darkly to lightly pigmented. We hypothesize that some larvae are more heavily pigmented to reduce UVR damage, while other species travelling in subsurface currents with low UVR might be more transparent. Linking larval morphology to depth‐dependent selective pressures would add a key element to help improve predictions of larval vertical distributions, which are important for simulating larval transport trajectories. We quantitatively tested the hypothesis that selection may have favored photoprotective pigmentation for larvae in the predominantly transparent plankton community while testing the differential effects of UVA and UVB radiation. We measured larval pigmentation of 12 species of crabs and exposed them to visible light only, visible + UVA, or visible + UVA + UVB in the tropics. Controlling for phylogeny, more pigmented species survived UVR better than less pigmented species, especially on sunnier days, though intraspecific comparisons for four species were equivocal. Most species died even from UVA exposure, which has long been regarded as relatively harmless despite penetrating deeper underwater than UVB. Thus, we demonstrate with a phylogenetically controlled analysis that crab larvae are pigmented in the predominantly transparent planktonic community to protect from UVR, improving our understanding of the selective forces acting on animal coloration and the factors determining planktonic distributions, survival, and dispersal. This linkage of morphology with susceptibility will be important for developing mechanistic models of environmental stress responses to better predict larval dispersal in current and future climates.
Development of a PRiME cartridge purification method for rapid determination of malachite green and leucomalachite green in Chinese softshell turtle
Authors: Shen Qing , Wang Jie , Chen Kang , Li Shiyan , Wang Yang , Wang Haixing 
Published: March 2019

AbstractA high‐throughput PRiME (process, robustness, improvements, matrix effects, ease of use) sample purification procedure was developed to simplify the multiple steps of traditional SPE in extracting the malachite green and leucomalachite green in Chinese softshell turtle (Pelodiscus sinensis). The sample loading volume, extracting solvent type, and pH value of the employed PRiME hydrophilic‐lipophilic balance cartridge for sample purification were optimized to be 3 mL, acetonitrile, and pH 5, respectively. In comparison with traditional SPE, the PRiME process is cost‐effective, solvent‐saving, and simple to operate, which only consists of a passing through step without traditional sorbent conditioning and impurity washing. Afterward, eluate was analyzed by ultra‐performance liquid chromatography‐tandem mass spectrometry, and the proposed method was validated for linearity (R2 > 0.9992), intraday precision (2.44–3.22%), interday precision (3.28–6.58%), sensitivity (LOD ≤ 0.18 μg/kg and, LOQ ≤ 0.60 μg/kg), and recovery (88.7–94.1%, RSD < 6.79%). The results indicated that the PRiME technique can simplify the sample preparation procedure by avoiding the tedious steps, such as conditioning, washing, etc. It would be of significant interest for environmental and food safety applications in the market of Chinese softshell turtle and related products.
A screening questionnaire for generalized tonic‐clonic seizures: Hospital‐based validation vs field‐validation method
Authors: Giuliano Loretta , Cicero Calogero Edoardo , Crespo Gómez Elizabeth Blanca , Sofia Vito , Zappia Mario , Nicoletti Alessandra 
Published: March 2019

SummaryThe majority of the screening questionnaires for epilepsy have been validated in hospital settings. We previously developed and used for field validation a screening tool to detect generalized tonic‐clonic seizures (GTCS) in the rural communities of the Chaco region of Bolivia. The objective of the present study was to perform a hospital‐based validation of the same questionnaire and to compare the levels of accuracy obtained when validated in the field or in a hospital‐based context. We carried out a hospital‐based validation in the Hospital Hernandez Vera of Santa Cruz, Bolivia, where we enrolled patients affected by epilepsy with GTCS and controls. Sensitivity, specificity, and positive and negative predictive values (PPV and NPV) were calculated. One hundred twenty questionnaires were administered to 59 patients (27 men [45.8%]; mean age ± SD = 32.4 ± 14.2 years) and 61 controls (27 men [44.3%]; mean age ± SD = 32.6 ± 14.3 years). We obtained levels of accuracy of 100%. Sensitivity and PPV were significantly higher than the estimates obtained in the field‐validation study (sensitivity 100% vs 76.3%; PPV 100% vs 69.0%). Our screening questionnaire showed a significantly lower level of sensitivity when validated in the field, confirming that hospital‐based validation can lead to an overestimation of sensitivity.
Generation and combination of the solar cells: A current model review
Authors: Khatibi Ali , Razi Astaraei Fatemeh , Ahmadi Mohammad Hossein 
Published: March 2019

AbstractGenerally, first and second generations of photovoltaic (PV) cells are including mono‐crystalline silicon, amorphous silicon, and dye‐synthesized solar cells. Investigating the electrical current behavior of these sorts of PV cells shows that a modified multi‐ or single diode(s) model with shunt and series resistance can use as a good choice in a specific range of the current. For other constructions such as multi‐junction PV cells that consist of the third generation, the network models are the best choice. Also, the network models can be used for the first and second generations to improve the validity of model in the wider range of current. In addition to existing generations, PV array and modules, which are serial and parallel arrays of PV cells, will lead to a higher current or voltage. The main disadvantage of using these sorts of systems is their more space occupation. This problem can be solved by using the concentrated PV (CPV) systems that focus the received irradiation on a smaller surface. By considering the generated current, voltage, power, temperature effect, and financial analysis, it seems third‐generation PV systems are more efficient among all the generations. Finally, by considering the ratio of generated current on the occupied space, the CPV systems will be a better choice.
Effect of the nonaxisymmetric endwall on wet steam condensation flow in a stator cascade
Authors: Han Xu , Zeng Wei , Han Zhonghe , Li Peng , Qian Jiangbo 
Published: March 2019

AbstractSteam turbines are critical pieces of power equipment in the electric power industry, and the study of wet steam condensation flow is important for improving the efficiency and safety of steam turbines. Wet steam nucleation, which is the main reason for thermodynamic losses, usually occurs downstream of the stator cascade. The mechanism of secondary flow loss control by the nonaxisymmetric endwall is the change of pressure distribution in the cascade channel. This mechanism also affects the wet steam condensation phenomenon. The positive/cosine function was proposed for endwall modification in the nucleation stage of a steam turbine. The design method presented in this paper can be used to produce endwall protrusions with different heights at different axial chords. To analyze the influence of the endwall protrusion design parameters on the condensation flow, nine endwall protrusion models were set up at varied axial positions. In comparison with the original cascade, the total pressure loss coefficient and outlet wetness were found to be ideal when the endwall protrusion maximum height was located at the 50% axial chord length of the stator and the protrusion was 3% of the blade height. The ideal incidence angle of this modified cascade was from −2° to + 10°.
Quantifying bed‐related suspended load in gravel bed rivers through an analysis of the bedload‐suspended load relationship
Authors: Misset C. , Recking A. , Navratil O. , Legout C. , Poirel A. , Cazilhac M. , Briguet V. , Esteves M. 
Published: March 2019

AbstractSuspended load transport can strongly impact ecosystems, dam filling and water resources. However, contrary to bedload, the use of physically based predicting equations is very challenging because of the complexity of interactions between suspended load and the river system. Through the analysis of extensive data sets, we investigated extent to which one or several river bed or flow parameters could be used as a proxy for quantifying suspended fluxes in gravel bed rivers. For this purpose, we gathered in the literature nearly 2400 instantaneous field measurements collected in 56 gravel bed rivers. Among all standard dimensionless parameters tested, the strongest correlation was observed between the suspended sediment concentration and the dimensionless bedload rate. An empirical relation between these two parameters was calibrated. Used with a reach average bedload transport formula, the approach allowed to successfully reproduce suspended fluxes measured during major flood events in seven gravel bed alpine rivers, morphodynamically active and distant from hillslope sources. These results are discussed in light of the complexity of the processes potentially influencing suspended load in a mountainous context. The approach proposed in this paper will never replace direct field measurements, which can be considered the only confident method to assess sediment fluxes in alpine streams; however, it can increment existing panel tools that help river managers to estimate even rough but not unrealistic suspended fluxes when measurements are totally absent. © 2019 John Wiley & Sons, Ltd.
Effects of Dissolved Organic Carbon on Copper Toxicity to Embryos of Mytilus galloprovincialis as Measured by Diffusive Gradient in Thin Films
Authors: Strivens Jonathan , Hayman Nicholas , Johnston Robert , Rosen Gunther 
Published: March 2019

Abstract
Diffusive gradient in thin films (DGT) potentially better quantifies bioavailable copper (Cu) in seawater. Laboratory exposure of DGTs and Mytilus galloprovincialis embryos at varying concentrations of dissolved organic carbon and Cu were performed to resolve the degree to which mimicry of toxicity buffering occurs in passive sampler quantification. The results provide preliminary median effect concentrations (EC50s) ranging from 4.8 to 11.5 µg/L as CDGT Cu over the span of 0.896 to 8.36 mg/L DOC. Environ Toxicol Chem 2019;00:1-6. Published 2019 Wiley Periodicals, Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.
Different Methods of Adjusting for Form Difficulty Under the Rasch Model: Impact on Consistency of Assessment Results
Authors: Manna Venessa F. , Gu Lixiong 
Published: March 2019

AbstractWhen using the Rasch model, equating with a nonequivalent groups anchor test design is commonly achieved by adjustment of new form item difficulty using an additive equating constant. Using simulated 5‐year data, this report compares 4 approaches to calculating the equating constants and the subsequent impact on equating results. The 4 approaches are mean difference, mean difference with outlier removal using the 0.3 logit rule, mean difference with robust z statistic, and the information‐weighted mean difference. Factors studied included sample size, anchor test length, percentage of anchor items displaying outlier behavior, and the distribution of test item difficulty relative to examine ability. The results indicated that the mean difference and information‐weighted mean difference methods performed similarly across all conditions. In addition, with larger sample sizes, the mean difference with 0.3 logit method performed similarly to these 2 methods. The mean difference with robust z method performed most differently from the other three methods of calculating the equating constant. This method removed a large percentage of the anchor items compared to the mean difference with 0.3 logit method but seemed to produce the most stable trend in performance classification across the 5 years, particularly when sample sizes were large.
Examining the Calibration Process for Raters of the GRE® General Test
Authors: Wendler Cathy , Glazer Nancy , Cline Frederick 
Published: March 2019

AbstractOne of the challenges in scoring constructed‐response (CR) items and tasks is ensuring that rater drift does not occur during or across scoring windows. Rater drift reflects changes in how raters interpret and use established scoring criteria to assign essay scores. Calibration is a process used to help control rater drift and, as such, serves as a type of quality control during CR scoring. Calibration sets are designed to provide sufficient evidence that raters have understood and internalized the rubrics and can score accurately across all score points of the score scale. This study examined the calibration process used to qualify raters to score essays from the GRE® Analytical Writing measure. A total of 46 experienced raters participated in the study, and each rater scored up to 630 essays from 1 of 2 essay prompt types. Two research questions were evaluated: Does calibration influence scoring accuracy? and Does reducing the frequency of calibration impact scoring accuracy? While the distribution of score points represented by the essays used in the study did not necessarily reflect what raters see during operational scoring, results suggest that the influence of calibration on Day 1 remains with raters through at least 3 scoring days. Results further suggest that scoring accuracy may be moderated by prompt type. Nevertheless, study results indicate that daily calibration for GRE prompt types may not be necessary and that reducing the frequency of calibration is unlikely to reduce scoring accuracy.
Concurrent chemoradiotherapy with weekly versus triweekly cisplatin in locally advanced squamous cell carcinoma of the head and neck: Comparative analysis
Authors: Mohamed Amr , Twardy Brandon , Zordok Magdi A. , Ashraf Khuram , Alkhoder Ayman , Schrapp Kelly , Steuer Conor , Chen Zhengjia , Pakkala Suchita , Pillai Rathi , Trad Wadsworth J , Higgins Kristin , Beitler Jonathan J. , Ramalingam Suresh S. , Owonikoko Taofeek K. , Khuri Fadlo R. , Shin Dong M. , Behera Madhusmita , Saba Nabil F. 
Published: March 2019

AbstractBackgroundCisplatin‐based chemoradiotherapy is standard of care for locally advanced squamous cell carcinoma of the head and neck. This systemic review compared efficacy and safety of weekly vs triweekly cisplatin in locally advanced squamous cell carcinoma of the head and neck.MethodsAmong 1500 prospective studies published from 1970 to 2015, 39 (18 weekly, 21 triweekly) including 3668 patients qualified for inclusion. Clinical outcomes were analyzed using weighted estimates and 2‐tailed t test for comparisons; significance level was 0.05.ResultsLocoregional control was 58% (CI 53%‐63%) vs 61% (CI 56%‐65%; P = .7). The 2‐year overall survival (OS) was 74% (CI 66%‐80%) for weekly vs 67% (64%‐69%) triweekly groups (P = .67). The 2‐year progression‐free survival (PFS) was 69% (CI 59%‐77%) for weekly vs 62% (CI 58%‐65%) triweekly groups (P = .9). Grade 3 to 5 toxicities were 36% vs 40% (P = .37) in weekly vs triweekly groups.ConclusionsWeekly cisplatin was comparable in efficacy and safety to the triweekly regimen. Our analysis supports the use of weekly or triweekly cisplatin in locally advanced squamous cell carcinoma of the head and neck, with tolerability being a key factor in selection.
Monitoring the neutrophil‐to‐lymphocyte ratio may be useful for predicting the anticancer effect of nivolumab in recurrent or metastatic head and neck cancer
Authors: Yasumatsu Ryuji , Wakasaki Takahiro , Hashimoto Kazuki , Nakashima Koichiro , Manako Tomomi , Taura Masahiko , Matsuo Mioko , Nakagawa Takashi 
Published: March 2019

AbstractBackgroundPredicting the response to treatment with nivolumab and the survival in patients with recurrent or metastatic head and neck squamous cell carcinoma (HNSCC) remains a challenge. We investigated whether or not the neutrophil‐to‐lymphocyte ratio (NLR) kinetics could be used to predict the anticancer effect of nivolumab.Patients and MethodsForty‐one patients with recurrent or metastatic HNSCC who had been treated with nivolumab were retrospectively analyzed. The NLR was calculated using pretreatment blood test results until the end of the treatment.ResultsThe posttreatment NLR was higher than the pretreatment value in 13 of 17 patients (76%) patients with progressive disease within the first 3 months, whereas the posttreatment NLR was lower than the pretreatment value in 10 of 11 patients (91%) with stable disease or partial response during the follow‐up period.ConclusionOur results indicate that monitoring the NLR may aid in the earlier confirmation of treatment failure in patients with recurrent or metastatic HNSCC during nivolumab monotherapy.
Calcium sulfate bone cements with nanoscaled silk fibroin as inducer
Authors: Xu Rui , Lian Xiaojie , Shen Yiling , Zhang Yue , Niu Baolong , Zhang Siruo , Guo Qi , Zhang Quanyou , Du Jingjing , Li Fen , Lu Qiang , Huang Di , Wei Yan 
Published: March 2019

AbstractBoth nanostructures and conformations of different protein/polysaccharide additives have critical influence on the performance of calcium sulfate (CS) bone cements. Silk fibroin (SF) as matrix and additives has been introduced to develop bone scaffolds and cements. Here, β‐sheet‐rich SF nanofibers (SFF) was used to tune the solidification of CS, achieving better mechanical and biological properties. The ratio of SFF was adjusted to further optimize CS functions. Compared to that regulated with natural silk fibers (NSF) and SF solutions (SFS), the SFF‐induced CS showed smaller size and more filament structures. Better mechanical properties were achieved, suggesting the superiority of the SFF as the solidifying solution to combine with α‐calcium sulfate hemihydrate (α‐CSH) at the same liquid/solid (L/S) ratio. Scanning electron microscope, X‐ray diffraction, Fourier transform infrared spectroscopy, setting time, porosity, mechanical performance test, degradation performance test, and water resistance test were used to demonstrate the properties of this bone repair cement. Cell culture experiments in vitro was used to evaluate the biocompatibility of this composited material. In conclusion, the results demonstrated that nanofibers was a better form of SF in the modification of CSH cement. And the research conducted in this article on improving the mechanical and biological properties of CSH would supported the reference for later clinical experiments. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B:2611–2619, 2019.