bluuebunny/crossref_metadata_2025_split huggingface dataset:
Critical time for weed removal in glyphosate-resistant soybean as influenced by preemergence herbicides
Authors: Knezevic Stevan Z. , Pavlovic Pavle , Osipitan O. Adewale , Barnes Ethann R. , Beiermann Clint , Oliveira Maxwel C. , Lawrence Nevin , Scott Jon E. , Jhala Amit 
Published: April 2019

AbstractWidespread and repeated use of glyphosate resulted in an increase in glyphosate-resistant (GR) weeds. This led to an urgent need for diversification of weed control programs and use of PRE herbicides with alternative sites of action. Field experiments were conducted over a 4-yr period (2015 to 2018) across three locations in Nebraska to evaluate the effects of PRE-applied herbicides on critical time for weed removal (CTWR) in GR soybean. The studies were laid out in a split-plot arrangement with herbicide regime as the main plot and weed removal timing as the subplot. The herbicide regimes used were either no PRE or premix of either sulfentrazone plus imazethapyr (350 + 70 g ai ha−1) or saflufenacil plus imazethapyr plus pyroxasulfone (26 + 70 + 120 g ai ha−1). The weed removal timings were at V1, V3, V6, R2, and R5 soybean stages, with weed-free and weedy season-long checks. Weeds were removed by application of glyphosate (1,400 g ae ha−1) or by hoeing. The results across all years and locations suggested that the use of PRE herbicides delayed CTWR in soybean. In particular, the CTWR without PRE herbicides was determined to be around the V1 to V2 (14 to 21 d after emergence [DAE]) growth stage, depending on the location and weed pressure. The use of PRE-applied herbicides delayed CTWR from about the V4 (28 DAE) stage up to the R5 (66 DAE) stage. These results suggest that the use of PRE herbicides in GR soybean could delay the need for POST application of glyphosate by 2 to 5 wk, thereby reducing the need for multiple applications of glyphosate during the growing season. Additionally, the use of PRE herbicides could provide additional modes of action needed to manage GR weeds in GR soybean.
The Penultimate Glacial Termination and Variability of the Pacific Intertropical Convergence Zone
Authors: Reimi M. A. , Marcantonio F. , Lynch‐Stieglitz J. , Jacobel A. W. , McManus J. F. , Winckler G. 
Published: April 2019

AbstractUnderstanding how the Intertropical Convergence Zone (ITCZ) responds to abrupt climate change is essential for reconstructing large‐scale atmospheric circulation across climate transitions. However, key differences between dynamical models and observational constraints on ITCZ movement remain unresolved. Here, we examine the Pb and Nd radiogenic isotope signatures of dust deposited in the central equatorial Pacific (CEP) from 160 to 105 kyr. We quantified the relative contributions of Northern Hemisphere‐ and Southern Hemisphere‐sourced dust to the CEP. In contrast with previous model estimates, we demonstrate that South America is an important source of dust to the CEP during glacial periods. Our new observations provide a critical data set for verifying dynamical arguments about tropical hydroclimate. We infer that the southernmost position of the ITCZ precipitation centroid occurs between 136 and 131 kyr, coincident with the timing of North Atlantic Heinrich Stadial Event 11 (136 to 129 kyr).
Correction of Ionospheric Distortion on HF Hybrid Sky‐Surface Wave Radar Calibrated by Direct Wave
Authors: Zhou Qing , Yue Xianchang , Zhang Lan , Wu Xingbin , Wang Longgang 
Published: April 2019

AbstractThe performance of the high‐frequency hybrid sky‐surface wave radar is often degraded due to the distortion of radar echoes induced by time‐varying ionosphere. Here a modified S‐transform method based on the direct wave for ionosphere decontamination of high‐frequency hybrid sky‐surface wave radar is presented. First, we extract the time‐varying‐ionosphere‐distorted phase of the echoes from the direct wave of high‐frequency hybrid sky‐surface wave radar by using the modified S‐transform. Then this phase function is used to decontaminate the ionosphere distortion of radar echo at each range bins. Simulations and experimental data are conducted to validate the performance of the proposed method on decontaminating the distortion. The experimental data are acquired by Wuhan Universitys ocean state measuring and analyzing radar. A mass of radar data is processed and analyzed, demonstrating that the decontamination effect is statistically significant. The method is not only effective to remove the Doppler shift of direct wave and Bragg peaks caused by ionosphere but also able to narrow the broadened direct wave and Bragg peaks. Meanwhile, the SNR is improved in most range bins; the background noise is reduced detectably, sometimes significantly; and some isolated radar echoes near direct wave or Bragg peaks are recovered or enhanced. These results indicate that the proposed decontamination algorithm works well.
Pattern of Ionization Gradient, Solar Quiet Magnetic Element, and F2‐Layer Bottomside Thickness Parameter at African Equatorial Location
Authors: Adebesin B. O. , Adeniyi J. O. , Adimula I. A. , Adebiyi S. J. , Ikubanni S. O. , Oladipo O. A. , Olawepo A. O. 
Published: April 2019

AbstractThe study of ionization gradient (dN/dh) profile in the description of ionospheric dynamics is not common. This is the first attempt at finding the dependence of ionization gradient, solar quiet component (Sq (BH)), and bottomside thickness parameter (B0) in the African equatorial sector. Digisonde and Magnetic Data Acquisition System data collocated at an equatorial location were employed. Result was presented for sunrise (00 LT), midday (12 LT), sunset (18 LT), and midnight (00 LT) hours. The ionization gradient peak height remains unchanged at midday across all months. A percentage correlation of 93% existed in the inverse and direct linear relationship of dN/dh‐B0 at sunrise, and of Sq (BH)‐B0 at midday, respectively. Significant relationship between dN/dh and Sq (BH) was at sunset; for other hours, the relationship is poor. The multiple linear relationship of dN/dh‐Sq (BH)‐B0 parameters revealed that the dependence of dN/dh on Sq (BH) and B0 is highest at midday, and a model equation was presented. The dependence of dN/dh on the solar activity index (F10.7) holds at all the selected hours, and distinct only at midday and midnight for the Sq (BH)‐F10.7 and B0‐F10.7 patterns. Both the peak ionization gradient and the height it occurs maximizes/minimizes at 18 LT/06 LT. The importance of the F region dynamo at heights above 150 km was reported.
Large‐Amplitude Electromagnetic Ion Cyclotron Waves and Density Fluctuations in the Flank of the Earth's Magnetosheath
Authors: Zhao J. S. , Wang T. Y. , Dunlop M. W. , Shi C. , He J. S. , Dong X. C. , Wu D. J. , Giles B. , Russell C. T. 
Published: April 2019

AbstractThe electromagnetic ion cyclotron (EMIC) wave usually observed in the Earth's magnetosheath is thought to be generated through the ion temperature anisotropy instability. This paper presents an observation of a long‐lasting large‐amplitude EMIC wave event in the dawnside flank of the magnetosheath by the Magnetospheric Multiscale mission, lasting from 06:33:00 to 12:35:00 UT on 16 April 2018. The wave amplitude is around 0.2 nT as compared to the ambient magnetic field ~12 nT. The characteristic frequency and scale size are around 0.2 Hz and 1,028 km, respectively. Accompanying EMIC waves are density fluctuations, which exhibit both positive and negative correlations with the longitudinal magnetic field. Using the fitted parameters for the ion and electron phase space densities, plasma kinetic theory predicts local excitations of both EMIC and mirror instabilities, which provide the energy of these observed EMIC waves and density fluctuations.
Volume, Heat, and Freshwater Divergences in the Subpolar North Atlantic Suggest the Nordic Seas as Key to the State of the Meridional Overturning Circulation
Authors: Chafik Léon , Rossby T. 
Published: April 2019

AbstractThe meridional overturning circulation (MOC) decreases rapidly in subpolar and Nordic regions where the warm upper layer loses its buoyancy due to intense heat loss, sinks, and flows south. The major volume loss of the upper limb of the MOC, ~9.6 Sv out of 18.4 ± 3.4 Sv, occurs as subduction across the Iceland Basin and Irminger Sea while the major heat loss, 273 TW out of 395 ± 74 TW is associated with the MOC branch that continues into the Nordic Seas where North Atlantic deep overflow water is produced. The 122 ± 79 TW heat flux convergence in the subpolar gyre appears to be significantly larger than various estimates of heat loss to the atmosphere. Much of the 0.09 ± 0.02 Sv freshwater divergence is presumably balanced by runoff from the Greenland shelf. These estimates suggest that the Nordic Seas, not the Labrador Sea, are key to the state of the MOC.
Human‐Induced Changes in Holocene Nitrogen Cycling in North China: An Isotopic Perspective From Sedimentary Pyrogenic Material
Authors: Wang Xu , Cui Linlin , Yang Saihong , Xiao Jule , Ding Zhongli 
Published: April 2019

AbstractReactive nitrogen (N) deposition from human activity significantly impacts temperate vegetation in areas where low natural N availability limits vegetative productivity. However, the ecosystem response to anthropogenic N deposition remains elusive owing to the scarcity of long‐term empirical observations. Here a N isotope of a pyrogenic material was used to investigate long‐term N availability evolution in a forest‐steppe ecosystem in North China. The N availability was found to have significantly increased since circa 7,400 years BP when primitive agriculture began. Different N availability changes were observed under primitive agriculture (6,600–3,500 cal. years BP) and Sui‐Tang traditional agriculture (AD 581–907), implying dependency on the agricultural mode. A 220‐year N availability recovery period after Sui‐Tang agriculture was observed. On this basis, a minimum of several hundred years is projected for the restoration of the temperate ecosystem if the modern N cascade were to be stopped.
Impact of Data Assimilation on Thermal Tides in the Case of Venus Express Wind Observation
Authors: Sugimoto Norihiko , Kouyama Toru , Takagi Masahiro 
Published: April 2019

AbstractImpacts of horizontal winds assimilation on thermal tides are investigated by using the Venus atmospheric general circulation model for the Earth Simulator local ensemble transform Kalman filter data assimilation system. The assimilated data are horizontal winds derived from Venus ultraviolet images taken by the Venus Monitoring Camera onboard the Venus Express orbiter. The results show that three‐dimensional structures of the thermal tides are significantly improved not only in the horizontal winds but also in the temperature field, even though the observations are available only at the cloud top level on the southern dayside hemisphere approximately once an Earth day. The reproduced temperature fields agree well with recent radio occultation measurements of the Venus Climate Orbiter Akatsuki. The zonal mean fields of the zonal wind and temperature are also improved globally. This study would enable reanalysis of past Venus observations.
A conserved CCM complex promotes apoptosis non-autonomously by regulating zinc homeostasis
Authors: Chapman Eric M. , Lant Benjamin , Ohashi Yota , Yu Bin , Schertzberg Michael , Go Christopher , Dogra Deepika , Koskimäki Janne , Girard Romuald , Li Yan , Fraser Andrew G. , Awad Issam A. , Abdelilah-Seyfried Salim , Gingras Anne-Claude , Derry W. Brent 
Published: April 2019

AbstractApoptotic death of cells damaged by genotoxic stress requires regulatory input from surrounding tissues. The C. elegans scaffold protein KRI-1, ortholog of mammalian KRIT1/CCM1, permits DNA damage-induced apoptosis of cells in the germline by an unknown cell non-autonomous mechanism. We reveal that KRI-1 exists in a complex with CCM-2 in the intestine to negatively regulate the ERK-5/MAPK pathway. This allows the KLF-3 transcription factor to facilitate expression of the SLC39 zinc transporter gene zipt-2.3, which functions to sequester zinc in the intestine. Ablation of KRI-1 results in reduced zinc sequestration in the intestine, inhibition of IR-induced MPK-1/ERK1 activation, and apoptosis in the germline. Zinc localization is also perturbed in the vasculature of krit1−/− zebrafish, and SLC39 zinc transporters are mis-expressed in Cerebral Cavernous Malformations (CCM) patient tissues. This study provides new insights into the regulation of apoptosis by cross-tissue communication, and suggests a link between zinc localization and CCM disease.
Laser restructuring and photoluminescence of glass-clad GaSb/Si-core optical fibres
Authors: Song S. , Lønsethagen K. , Laurell F. , Hawkins T. W. , Ballato J. , Fokine M. , Gibson U. J. 
Published: April 2019

AbstractSemiconductor-core optical fibres have potential applications in photonics and optoelectronics due to large nonlinear optical coefficients and an extended transparency window. Laser processing can impose large temperature gradients, an ability that has been used to improve the uniformity of unary fibre cores, and to inscribe compositional variations in alloy systems. Interest in an integrated light-emitting element suggests a move from Group IV to III-V materials, or a core that contains both. This paper describes the fabrication of GaSb/Si core fibres, and a subsequent CO2 laser treatment that aggregates large regions of GaSb without suppressing room temperature photoluminescence. The ability to isolate a large III-V crystalline region within the Si core is an important step towards embedding semiconductor light sources within infrared light-transmitting silicon optical fibre.
Spatiotemporal control of coacervate formation within liposomes
Authors: Deshpande Siddharth , Brandenburg Frank , Lau Anson , Last Mart G. F. , Spoelstra Willem Kasper , Reese Louis , Wunnava Sreekar , Dogterom Marileen , Dekker Cees 
Published: April 2019

AbstractLiquid-liquid phase separation (LLPS), especially coacervation, plays a crucial role in cell biology, as it forms numerous membraneless organelles in cells. Coacervates play an indispensable role in regulating intracellular biochemistry, and their dysfunction is associated with several diseases. Understanding of the LLPS dynamics would greatly benefit from controlled in vitro assays that mimic cells. Here, we use a microfluidics-based methodology to form coacervates inside cell-sized (~10 µm) liposomes, allowing control over the dynamics. Protein-pore-mediated permeation of small molecules into liposomes triggers LLPS passively or via active mechanisms like enzymatic polymerization of nucleic acids. We demonstrate sequestration of proteins (FtsZ) and supramolecular assemblies (lipid vesicles), as well as the possibility to host metabolic reactions (β-galactosidase activity) inside coacervates. This coacervate-in-liposome platform provides a versatile tool to understand intracellular phase behavior, and these hybrid systems will allow engineering complex pathways to reconstitute cellular functions and facilitate bottom-up creation of synthetic cells.
A potential sensing mechanism for DNA nucleobases by optical properties of GO and MoS2 Nanopores
Authors: Faramarzi Vahid , Ahmadi Vahid , Fotouhi Bashir , Abasifard Mostafa 
Published: April 2019

AbstractWe propose a new DNA sensing mechanism based on optical properties of graphene oxide (GO) and molybdenum disulphide (MoS2) nanopores. In this method, GO and MoS2 is utilized as quantum dot (QD) nanopore and DNA molecule translocate through the nanopore. A recently-developed hybrid quantum/classical method (HQCM) is employed which uses time-dependent density functional theory and quasi-static finite difference time domain approach. Due to good biocompatibility, stability and excitation wavelength dependent emission behavior of GO and MoS2 we use them as nanopore materials. The absorption and emission peaks wavelengths of GO and MoS2 nanopores are investigated in the presence of DNA nucleobases. The maximum sensitivity of the proposed method to DNA is achieved for the 2-nm GO nanopore. Results show that insertion of DNA nucleobases in the nanopore shifts the wavelength of the emitted light from GO or MoS2 nanopore up to 130 nm. The maximum value of the relative shift between two different nucleobases is achieved by the shift between cytosine (C) and thymine (T) nucleobases, ~111 nm for 2-nm GO nanopore. Results show that the proposed mechanism has a superior capability to be used in future DNA sequencers.
Delayed maturation of GABAergic signaling in the Scn1a and Scn1b mouse models of Dravet Syndrome
Authors: Yuan Yukun , O’Malley Heather A. , Smaldino Melissa A. , Bouza Alexandra A. , Hull Jacob M. , Isom Lori L. 
Published: April 2019

AbstractDravet syndrome (DS) is a catastrophic developmental and epileptic encephalopathy characterized by severe, pharmacoresistant seizures and the highest risk of Sudden Unexpected Death in Epilepsy (SUDEP) of all epilepsy syndromes. Here, we investigated the time course of maturation of neuronal GABAergic signaling in the Scn1b−/− and Scn1a+/− mouse models of DS. We found that GABAergic signaling remains immature in both DS models, with a depolarized reversal potential for GABAA-evoked currents compared to wildtype in the third postnatal week. Treatment of Scn1b−/− mice with bumetanide resulted in a delay in SUDEP onset compared to controls in a subset of mice, without prevention of seizure activity or amelioration of failure to thrive. We propose that delayed maturation of GABAergic signaling may contribute to epileptogenesis in SCN1B- and SCN1A-linked DS. Thus, targeting the polarity of GABAergic signaling in brain may be an effective therapeutic strategy to reduce SUDEP risk in DS.
Surface modification on MoO2+x/Mo(110) induced by a local electric potential
Authors: Bozhko Sergey I. , Walshe Killian , Tulina Natalia , Walls Brian , Lübben Olaf , Murphy Barry E. , Bozhko Vladimir , Shvets Igor V. 
Published: April 2019

AbstractOxygen adatoms on the MoO2+x/Mo(110) surface are observed to be removed when a sufficiently large bias is applied between the scanning tunneling microscope tip and the surface. Experimental observations, such as the bias polarity dependence of adatom removal and the observation of an intermediate state, indicate that the adatom penetrates the surface oxide layer. Through the comparison of finite element method simulations with various experimental relationships, the electric field is concluded to be the sole contributor to adatom penetration into the surface oxide layer. The energetic barrier to this process is estimated to be approximately 0.45 eV in magnitude. Furthermore, the resolution of this phenomenon is on the atomic scale: individual adatoms can undergo surface penetration whilst their nearest neighbour adatoms, separated by 5 Å, are unaffected. The mechanism reported here has the advantages of not strongly influencing the substrate and is exceptionally localised, which can be beneficial for the synthesis of single atom devices.
Visualizing flow in an intact CSF network using optical coherence tomography: implications for human congenital hydrocephalus
Authors: Date Priya , Ackermann Pascal , Furey Charuta , Fink Ina Berenice , Jonas Stephan , Khokha Mustafa K. , Kahle Kristopher T. , Deniz Engin 
Published: April 2019

AbstractCerebrospinal fluid (CSF) flow in the brain ventricles is critical for brain development. Altered CSF flow dynamics have been implicated in congenital hydrocephalus (CH) characterized by the potentially lethal expansion of cerebral ventricles if not treated. CH is the most common neurosurgical indication in children effecting 1 per 1000 infants. Current treatment modalities are limited to antiquated brain surgery techniques, mostly because of our poor understanding of the CH pathophysiology. We lack model systems where the interplay between ependymal cilia, embryonic CSF flow dynamics and brain development can be analyzed in depth. This is in part due to the poor accessibility of the vertebrate ventricular system to in vivo investigation. Here, we show that the genetically tractable frog Xenopus tropicalis, paired with optical coherence tomography imaging, provides new insights into CSF flow dynamics and role of ciliary dysfunction in hydrocephalus pathogenesis. We can visualize CSF flow within the multi-chambered ventricular system and detect multiple distinct polarized CSF flow fields. Using CRISPR/Cas9 gene editing, we modeled human L1CAM and CRB2 mediated aqueductal stenosis. We propose that our high-throughput platform can prove invaluable for testing candidate human CH genes to understand CH pathophysiology.
Microbial Community Dynamics During Lake Ice Freezing
Authors: Butler Timothy M. , Wilhelm Anna-Catharina , Dwyer Amber C. , Webb Paige N. , Baldwin Andrew L. , Techtmann Stephen M. 
Published: April 2019

AbstractMany freshwater environments experience dramatic seasonal changes with some systems remaining ice-covered for most of the winter. Freshwater systems are also highly sensitive to environmental change. However, little is known about changes in microbial abundance and community composition during lake ice formation and times of persistent ice cover. The goal of this study is to characterize temporal dynamics of microbial communities during ice formation and persistent ice cover. Samples were collected in triplicate, five days per week from surface water in the Keweenaw Waterway between November and April. Environmental conditions along with microbial abundance and microbial community composition was determined. Distinct community composition was found between ice-free and ice-covered time periods with significantly different community composition between months. The microbial community underwent dramatic shifts in microbial abundance and diversity during the transitions into and out of ice cover. The richness of the microbial community increased during times of ice cover. Relatives of microbes involved in nitrogen cycling bloomed during times of ice cover as sequences related to known nitrifying taxa were significantly enriched during ice cover. These results help to elucidate how microbial abundance and diversity change over drastic seasonal transitions and how ice cover may affect microbial abundance and diversity.
ITGA2 as a potential nanotherapeutic target for glioblastoma
Authors: Guo Peng , Moses-Gardner Alexander , Huang Jing , Smith Edward R. , Moses Marsha A. 
Published: April 2019

AbstractHigh grade gliomas, including glioblastoma (GBM), are the most common and deadly brain cancers in adults. Here, we performed a quantitative and unbiased screening of 70 cancer-related antigens using comparative flow cytometry and, for the first time, identified integrin alpha-2 (ITGA2) as a novel molecular target for GBM. In comparison to epidermal growth factor receptor (EGFR), a well-established GBM target, ITGA2 is significantly more expressed on human GBM cells and significantly less expressed on normal human glial cells. We also found that ITGA2 antibody blockade significantly impedes GBM cell migration but not GBM cell proliferation. To investigate the utility of ITGA2 as a therapeutic target in GBM, we designed and engineered an ITGA2 antibody-directed liposome that can selectively deliver doxorubicin, a standard-of-care chemotherapeutic agent, to GBM cells. This novel approach significantly improved antitumor efficacy. We also demonstrated that these ITGA2 antibody-directed liposomes can effectively breach the blood-brain tumor barrier (BBTB) in vitro via GBM-induced angiogenesis effects. These findings support further research into the use of ITGA2 as a novel nanotherapeutic target for GBM.