bluuebunny/crossref_metadata_2025_split huggingface dataset:
Role of phytohormones in aluminium rhizotoxicity
Authors: Kopittke Peter M 
Published: June 2016

AbstractElevated concentrations of soluble aluminium (Al) reduce root growth in acid soils, but much remains unknown regarding the toxicity of this Al as well as the mechanisms by which plants respond. This review examines changes in phytohormones in Al‐stressed plants. Al often results in a rapid ‘burst’ of ethylene in root apical tissues within 15–30 min, with this regulating an increase in auxin. This production of ethylene and auxin seems to be a component of a plant‐response to toxic Al, resulting in cell wall modification or regulation of organic acid release. There is also evidence of a role of auxin in the expression of Al toxicity itself, with Al decreasing basipetal transport of auxin, thereby potentially decreasing wall loosening as required for elongation. Increasingly, changes in abscisic acid in root apices also seem to be involved in plant‐responses to toxic Al. Changes in cytokinins, gibberellins and jasmonates following exposure to Al are also examined, although little information is available. Finally, although not a phytohormone, concentrations of nitric oxide change rapidly in Al‐exposed tissues. The information presented in this review will assist in focusing future research efforts in examining the importance of phytohormones in plant tissues exposed to toxic levels of Al.
Quality Selection, Sectoral Heterogeneity and Chinese Exports
Authors: Kneller Richard , Yu Zhihong 
Published: June 2016

AbstractRecent models of international trade have identified product quality as an important determinant of bilateral trade flows. In this paper we examine the relationship between the characteristics of the export market and the aggregate quality of products using Chinese data. We find evidence that product unit values vary with standard gravity variables in a different manner across sectors of the Chinese economy and run contrary to earlier findings for the USA. These results are not compatible with existing heterogeneous firm trade models with constant mark‐up and the extension to include product quality. We construct a heterogeneous firm trade model with quality differences and spatial price discrimination, and show that the model provides plausible explanations for our empirical finds as well as other existing findings in the literature.
A liquid chromatography–mass spectrometry platform for the analysis of phyllobilins, the major degradation products of chlorophyll in Arabidopsis thaliana
Authors: Christ Bastien , Hauenstein Mareike , Hörtensteiner Stefan 
Published: June 2016

SummaryDuring senescence, chlorophyll is broken down to a set of structurally similar, but distinct linear tetrapyrrolic compounds termed phyllobilins. Structure identification of phyllobilins from over a dozen plant species revealed that modifications at different peripheral positions may cause complex phyllobilin composition in a given species. For example, in Arabidopsis thaliana wild‐type, eight different phyllobilins have structurally been characterized to date. Accurate phyllobilin identification and quantification, which classically have been performed by high performance liquid chromatography (HPLC) and UV/vis detection, are, however, hampered because of their similar physiochemical properties and vastly differing abundances in plant extracts. Here we established a rapid method for phyllobilin identification and quantification that couples ultra‐HPLC with high‐resolution/high‐precision tandem mass spectrometry. Using Arabidopsis wild‐type and mutant lines that are deficient in specific phyllobilin‐modifying reactions, we identified a total of 16 phyllobilins, among them two that have not been described before in Arabidopsis. The single and collision‐induced dissociation tandem mass spectrometry data of all 16 Arabidopsis phyllobilins were collected in a mass spectrometry library, which is available to the scientific community. The library allows rapid detection and quantification of phyllobilins within and across Arabidopsis genotypes and we demonstrate its potential use for high‐throughput approaches and genome‐wide association studies in chlorophyll breakdown. By extending the library with phyllobilin data from other plant species in the future, we aim providing a tool for chlorophyll metabolite analysis as a measure of senescence for practical applications, such as post‐harvest quality control.
Inhibitory masking controls the threshold sensitivity of retinal ganglion cells
Authors: Pan Feng , Toychiev Abduqodir , Zhang Yi , Atlasz Tamas , Ramakrishnan Hariharasubramanian , Roy Kaushambi , Völgyi Béla , Akopian Abram , Bloomfield Stewart A. 
Published: June 2016

Key points
Retinal ganglion cells (RGCs) in dark‐adapted retinas show a range of threshold sensitivities spanning ∼3 log units of illuminance.
Here, we show that the different threshold sensitivities of RGCs reflect an inhibitory mechanism that masks inputs from certain rod pathways.
The masking inhibition is subserved by GABAC receptors, probably on bipolar cell axon terminals.
The GABAergic masking inhibition appears independent of dopaminergic circuitry that has been shown also to affect RGC sensitivity.
The results indicate a novel mechanism whereby inhibition controls the sensitivity of different cohorts of RGCs. This can limit and thereby ensure that appropriate signals are carried centrally in scotopic conditions when sensitivity rather than acuity is crucial.
AbstractThe responses of rod photoreceptors, which subserve dim light vision, are carried through the retina by three independent pathways. These pathways carry signals with largely different sensitivities. Retinal ganglion cells (RGCs), the output neurons of the retina, show a wide range of sensitivities in the same dark‐adapted conditions, suggesting a divergence of the rod pathways. However, this organization is not supported by the known synaptic morphology of the retina. Here, we tested an alternative idea that the rod pathways converge onto single RGCs, but inhibitory circuits selectively mask signals so that one pathway predominates. Indeed, we found that application of GABA receptor blockers increased the sensitivity of most RGCs by unmasking rod signals, which were suppressed. Our results indicate that inhibition controls the threshold responses of RGCs under dim ambient light. This mechanism can ensure that appropriate signals cross the bottleneck of the optic nerve in changing stimulus conditions.
Nerve Stimulation Enhances Task-Oriented Training in Chronic, Severe Motor Deficit After Stroke
Authors: Carrico Cheryl , Chelette Kenneth C. , Westgate Philip M. , Powell Elizabeth , Nichols Laurie , Fleischer Anne , Sawaki Lumy 
Published: June 2016

Background and Purpose—
A sensory-based intervention called peripheral nerve stimulation can enhance outcomes of motor training for stroke survivors with mild-to-moderate hemiparesis. Further research is needed to establish whether this paired intervention can have benefit in cases of severe impairment (almost no active movement).

Methods—
Subjects with chronic, severe poststroke hemiparesis (n=36) were randomized to receive 10 daily sessions of either active or sham stimulation (2 hours) immediately preceding intensive task-oriented training (4 hours). Upper extremity movement function was assessed using Fugl–Meyer Assessment (primary outcome measure), Wolf Motor Function Test, and Action Research Arm Test at baseline, immediately post intervention and at 1-month follow-up.

Results—

Statistically significant difference between groups favored the active stimulation group on Fugl–Meyer at postintervention (95% confidence interval [CI], 1.1–6.9;
P
=0.008) and 1-month follow-up (95% CI, 0.6–8.3;
P
=0.025), Wolf Motor Function Test at postintervention (95% CI, −0.21 to −0.02;
P
=0.020), and Action Research Arm Test at postintervention (95% CI, 0.8–7.3;
P
=0.015) and 1-month follow-up (95% CI, 0.6–8.4;
P
=0.025). Only the active stimulation condition was associated with (1) statistically significant within-group benefit on all outcomes at 1-month follow-up and (2) improvement exceeding minimal detectable change, as well as minimal clinically significant difference, on ≥1 outcomes at ≥1 time points after intervention.

Conclusions—
After stroke, active peripheral nerve stimulation paired with intensive task–oriented training can effect significant improvement in severely impaired upper extremity movement function. Further confirmatory studies that consider a larger group, as well as longer follow-up, are needed.

Clinical Trial Registration—

URL:
http://www.clinicaltrials.gov
. Unique identifier: NCT02633215.
A new species of the genus Oreonectes (Cypriniformes: Nemacheilidae) from Guizhou, China
Authors: DENG HUAIQING , XIAO NING , HOU XIUFA , ZHOU JIANG 
Published: June 2016

This study examined the morphological and phylogenetic characteristics of Oreonectes shuilongensis sp. nov. The genus Oreonectes is distributed only in southwestern China and northern Vietnam. Sixteen specimens of cavefish were captured in the Shuilong Township in Guizhou Province of China and identified as a new species of Oreonectes (Cypriniformes: Nemacheilidae). Maximum likelihood was used to construct phylogenetic trees based on data for Nemacheilidae species accessible on GenBank. Molecular phylogenetic analyses showed that O. shuilongensis is closely related to O. platycephalus from which it is distinguished by having 6 vs. 5 branched anal rays, ratio of body length to body height 7.0–7.9 vs. 5.6–7.0, ratio of head length to distance between eyes 3.5–4.9 vs. 2.0–2.4, naked vs. scaly body, densely distributed fine black stains except on abdomen, and semitransparent body. Oreonectes shuilongensis is the only species of the genus not distributed in Guangxi Province. This study has contributed to the overall knowledge about the distribution of Oreonectes.
CMIP5 Scientific Gaps and Recommendations for CMIP6
Authors: Stouffer R. J. , Eyring V. , Meehl G. A. , Bony S. , Senior C. , Stevens B. , Taylor K. E. 
Published: June 2016

Abstract
The Coupled Model Intercomparison Project (CMIP) is an ongoing coordinated international activity of numerical experimentation of unprecedented scope and impact on climate science. Its most recent phase, the fifth phase (CMIP5), has created nearly 2 PB of output from dozens of experiments performed by dozens of comprehensive climate models available to the climate science research community. In so doing, it has greatly advanced climate science. While CMIP5 has given answers to important science questions, with the help of a community survey we identify and motivate three broad topics here that guided the scientific framework of the next phase of CMIP, that is, CMIP6:How does the Earth system respond to changes in forcing?What are the origins and consequences of systematic model biases?How can we assess future climate changes given internal climate variability, predictability, and uncertainties in scenarios?
CMIP has demonstrated the power of idealized experiments to better understand how the climate system works. We expect that these idealized approaches will continue to contribute to CMIP6. The quantification of radiative forcings and responses was poor, and thus it requires new methods and experiments to address this gap. There are a number of systematic model biases that appear in all phases of CMIP that remain a major climate modeling challenge. These biases need increased attention to better understand their origins and consequences through targeted experiments. Improving understanding of the mechanisms’ underlying internal climate variability for more skillful decadal climate predictions and long-term projections remains another challenge for CMIP6.
Idealized Numerical Modeling of the Diurnal Cycle of Tropical Cyclones
Authors: Navarro Erika L. , Hakim Gregory J. 
Published: June 2016

Abstract
A numerical experiment is performed to evaluate the role of the daily cycle of radiation on axisymmetric hurricane structure. Although a diurnal response in high cloudiness has been well documented previously, the link to tropical cyclone (TC) structure and intensity remains unknown. Previous modeling studies attributed differences in results to experimental setup (e.g., initial and boundary conditions) as well as to radiative parameterizations. Here, a numerically simulated TC in a statistically steady state is examined for 300 days to quantify the TC response to the daily cycle of radiation.
Fourier analysis in time reveals a spatially coherent diurnal signal in the temperature, wind, and latent heating tendency fields. This signal is statistically different from random noise and accounts for up to 62% of the variance in the TC outflow and 28% of the variance in the boundary layer. Composite analysis of each hour of the day reveals a cycle in storm intensity: a maximum is found in the morning and a minimum in the evening, with magnitudes near 1 m s−1. Anomalous latent heating forms near the inner core of the storm in the late evening, which persists throughout the early morning. Examination of the radial–vertical wind suggests two distinct circulations: 1) a radiatively driven circulation in the outflow layer due to absorption of solar radiation and 2) a convectively driven circulation in the lower and middle troposphere due to anomalous latent heating. These responses are coupled and are periodic with respect to the diurnal cycle.
Impact of Upper-Tropospheric Temperature Anomalies and Vertical Wind Shear on Tropical Cyclone Evolution Using an Idealized Version of the Operational GFDL Hurricane Model
Authors: Tuleya Robert E. , Bender Morris , Knutson Thomas R. , Sirutis Joseph J. , Thomas Biju , Ginis Isaac 
Published: June 2016

Abstract
The GFDL hurricane modeling system, initiated in the 1970s, has progressed from a research tool to an operational system over four decades. This system is still in use today in research and operations, and its evolution will be briefly described. This study used an idealized version of the 2014 GFDL model to test its sensitivity across a wide range of three environmental factors that are often identified as key factors in tropical cyclone (TC) evolution: SST, atmospheric stability (upper-air thermal anomalies), and vertical wind shear (westerly through easterly). A wide range of minimum central pressure intensities resulted (905–980 hPa). The results confirm that a scenario (e.g., global warming) in which the upper troposphere warms relative to the surface will have less TC intensification than one with a uniform warming with height. The TC rainfall is also investigated for the SST–stability parameter space. Rainfall increases for combinations of SST increase and increasing stability similar to global warming scenarios, consistent with climate change TC downscaling studies with the GFDL model. The forecast system’s sensitivity to vertical shear was also investigated. The idealized model simulations showed weak disturbances dissipating under strong easterly and westerly shear of 10 m s−1. A small bias for greater intensity under easterly sheared versus westerly sheared environments was found at lower values of SST. The impact of vertical shear on intensity was different when a strong vortex was used in the simulations. In this case, none of the initial disturbances weakened, and most intensified to some extent.
Deep Convection and Column Water Vapor over Tropical Land versus Tropical Ocean: A Comparison between the Amazon and the Tropical Western Pacific
Authors: Schiro Kathleen A. , Neelin J. David , Adams David K. , Lintner Benjamin R. 
Published: June 2016

Abstract
The relationships between the onset of tropical deep convection, column water vapor (CWV), and other measures of conditional instability are analyzed with 2 yr of data from the DOE Atmospheric Radiation Measurement (ARM) Mobile Facility in Manacapuru, Brazil, as part of the Green Ocean Amazon (GOAmazon) campaign, and with 3.5 yr of CWV derived from global positioning system meteorology at a nearby site in Manaus, Brazil. Important features seen previously in observations over tropical oceans—precipitation conditionally averaged by CWV exhibiting a sharp pickup at high CWV, and the overall shape of the CWV distribution for both precipitating and nonprecipitating points—are also found for this tropical continental region. The relationship between rainfall and CWV reflects the impact of lower-free-tropospheric moisture variability on convection. Specifically, CWV over land, as over ocean, is a proxy for the effect of free-tropospheric moisture on conditional instability as indicated by entraining plume calculations from GOAmazon data. Given sufficient mixing in the lower troposphere, higher CWV generally results in greater plume buoyancies through a deep convective layer. Although sensitivity of buoyancy to other controls in the Amazon is suggested, such as boundary layer and microphysical processes, the CWV dependence is consistent with the observed precipitation onset. Overall, leading aspects of the relationship between CWV and the transition to deep convection in the Amazon have close parallels over tropical oceans. The relationship is robust to averaging on time and space scales appropriate for convective physics but is strongly smoothed for averages greater than 3 h or 2.5°.
Weakened Eastern Pacific El Niño Predictability in the Early Twenty-First Century
Authors: Zhao Mei , Hendon Harry H. , Alves Oscar , Liu Guoqiang , Wang Guomin 
Published: June 2016

AbstractPredictive skill for El Niño in the equatorial eastern Pacific across a range of forecast models declined sharply in the early twenty-first century relative to what was achieved in the late twentieth century despite ongoing improvements of forecast systems. This decline coincided with a shift in Pacific climate to an enhanced east–west surface temperature gradient across the Pacific and a stronger Walker circulation at the end of the twentieth century. Using seasonal forecast sensitivity experiments with the Australian Bureau of Meteorology coupled model POAMA2.4, the authors show that this shift in background climate acted to weaken key ocean–atmosphere feedbacks that amplify eastern Pacific El Niño, thus resulting in weaker variability that is less predictable. These results indicate that extreme El Niños, such as those that occurred in 1982/83 and 1997/98, were conditioned by the background climate and so were favored to occur in the late twentieth century. However, anticipating future changes in El Niño variability and predictability is an outstanding challenge because causes and prediction of low-frequency variations of Pacific climate have not yet been demonstrated.
Warm Season Evaluation of Soil Moisture Prediction in the Soil, Vegetation, and Snow (SVS) Scheme
Authors: Alavi Nasim , Bélair Stéphane , Fortin Vincent , Zhang Shunli , Husain Syed Z. , Carrera Marco L. , Abrahamowicz Maria 
Published: June 2016

Abstract
A new land surface scheme has been developed at Environment and Climate Change Canada (ECCC) to provide surface fluxes of momentum, heat, and moisture for the Global Environmental Multiscale (GEM) atmospheric model. In this study, the performance of the Soil, Vegetation, and Snow (SVS) scheme in estimating the surface and root-zone soil moisture is evaluated against the Interactions between Soil, Biosphere, and Atmosphere (ISBA) scheme currently used operationally at ECCC within GEM for numerical weather prediction. In addition, the sensitivity of SVS soil moisture results to soil texture and vegetation data sources (type and fractional coverage) has been explored. The performance of SVS and ISBA was assessed against a large set of in situ observations as well as the brightness temperature data from the Soil Moisture Ocean Salinity (SMOS) satellite over North America. The results indicate that SVS estimates the time evolution of soil moisture more accurately, and compared to ISBA, results in higher correlations with observations and reduced errors. The sensitivity tests carried out during this study revealed that the SVS soil moisture results are not affected significantly by the soil texture data from different sources. The vegetation data source, however, has a major impact on the soil moisture results predicted by SVS, and accurate specification of vegetation characteristics is therefore crucial for accurate soil moisture prediction.
Comments on “Incorporating the Effects of Moisture into a Dynamical Parameter: Moist Vorticity and Moist Divergence”
Authors: Schultz David M. , Spengler Thomas 
Published: June 2016

Abstract
In a recent article, Qian et al. introduced the quantities moist vorticity and moist divergence to diagnose locations of heavy rain. These quantities are constructed by multiplying the relative vorticity and divergence by relative humidity to the power k, where k = 10 in their article. Their approach is similar to that for the previously constructed quantity generalized moist potential vorticity. This comment critiques the approach of Qian et al., demonstrating that the moist vorticity, moist divergence, and by extension generalized moist potential vorticity are flawed mathematically and meteorologically. Raising relative humidity to the 10th power is poorly justified and is based on a single case study at a single time. No meteorological evidence is presented for why areas of moist vorticity and moist divergence should overlap with regions of 24-h accumulated rainfall. All three quantities have not been verified against the output of precipitation directly from the model nor is the approach of combining meteorological quantities into a single parameter appropriate in an ingredients-based forecasting approach. Researchers and forecasters are advised to plot the model precipitation directly and employ an ingredients-based approach, rather than rely on these flawed quantities.
Reply to “Comments on ‘Incorporating the Effects of Moisture into a Dynamical Parameter: Moist Vorticity and Moist Divergence’”
Authors: Qian Weihong , Jiang Ning , Du Jun 
Published: June 2016

AbstractMathematical derivation, meteorological justification, and comparison to model direct precipitation forecasts are the three main concerns recently raised by Schultz and Spengler about moist divergence (MD) and moist vorticity (MV), which were introduced in earlier work by Qian et al. That previous work demonstrated that MD (MV) can in principle be derived mathematically with a value-added empirical modification. MD (MV) has a solid meteorological basis. It combines ascent motion and high moisture: the two elements necessary for rainfall. However, precipitation efficiency is not considered in MD (MV). Given the omission of an advection term in the mathematical derivation and the lack of precipitation efficiency, MD (MV) might be suitable mainly for heavy rain events with large areal coverage and long duration caused by large-scale quasi-stationary weather systems, but not for local intense heavy rain events caused by small-scale convection. In addition, MD (MV) is not capable of describing precipitation intensity. MD (MV) worked reasonably well in predicting heavy rain locations from short to medium ranges as compared with the ECMWF model precipitation forecasts. MD (MV) was generally worse than (though sometimes similar to) the model heavy rain forecast at shorter ranges (about a week) but became comparable or even better at longer ranges (around 10 days). It should be reiterated that MD (MV) is not intended to be a primary tool for predicting heavy rain areas, especially in the short range, but is a useful parameter for calibrating model heavy precipitation forecasts, as stated in the original paper.