bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of long non‐coding RNA involved in atrazine‐induced testicular degeneration of Xenopus laevis
Authors: Sai Linlin , Qu Binpeng , Zhang Juan , Liu Jian , Jia Qiang , Bo Cunxiang , Zhang Yu , Yu Gongchang , Han Ru , Peng Cheng
Published: January 2019

Long non‐coding RNA (lncRNA) plays a critical role in male germline development. Atrazine (AZ) as an environmental endocrine disrupting chemical (EDCs) can induce male reproductive toxicity in amphibians. Our previous studies demonstrated that AZ can alter gene and circular RNA (circRNA) expression of damaged testes in Xenopus laevis (X. laevis). We furthered to investigate the lncRNA expression profiling in the testis of X. laevis. Over 3559 lncRNAs were detected by lncRNA sequencing. AZ induced 40 upregulated and 46 downregulated differentially expressed lncRNAs. KEGG analysis showed that AZ‐affected lncRNAs mainly involve in 19 pathways among which 12 pathways are found in circRNA analysis. This study for the first time demonstrated that AZ can alter lncRNAs which may play a role in testicular degeneration through regulating expressions of functional genes in X. laevis. Our data may provide more insights on the mechanism about male reproductive toxicity of EDCs.
Sonographic demonstration of fetal esophagus using three‐dimensional ultrasound imaging
Authors: Dall'Asta A. , Grisolia G. , Nanni M. , Volpe N. , Schera G. B. L. , Frusca T. , Ghi T.
Published: January 2019

Objective

To evaluate the feasibility of antenatal direct visualization of normal and abnormal fetal esophagus using three‐dimensional ultrasound (3D‐US) with Crystal Vue rendering technology.

Methods

Between February and April 2018, 3D‐US volumes were collected from a non‐consecutive series of singleton pregnancies, referred for clinically indicated detailed prenatal ultrasound at 19–28 weeks' gestation to one of two fetal medicine units in Italy. 3D volumes were acquired from a midsagittal section of the fetal thorax and upper abdomen with the fetus lying in supine position. Postprocessing with multiplanar mode was applied to orientate the volume and identify the esophagus. The region of interest was angled by approximately 30° to the spine and its thickness was adjusted in order to optimize visualization of the intrathoracic and intra‐abdominal course of the esophagus. Crystal Vue software was used for image rendering of the fetal trunk in the coronal plane. Postnatal follow‐up was available in all cases.

Results

During the study period, 91 pregnancies met the inclusion criteria and were recruited. The study cohort included two pregnancies with suspicion of esophageal atresia due to suboptimal visualization of the stomach. Of the 89 cases with normal stomach on two‐dimensional (2D) imaging, 3D‐US with Crystal Vue rendering technology allowed direct evaluation of the whole course of the esophagus in 74 (83.1%). In the two cases with small or absent stomach bubble on 2D imaging, esophageal atresia was demonstrated antenatally on 3D Crystal Vue imaging and was confirmed postnatally. The mean time required for offline postprocessing and visualization of the esophageal anatomy was 4 min.

Conclusions

Using 3D‐US with Crystal Vue rendering, it is possible to visualize antenatally the normal fetal esophagus and demonstrate presence of esophageal atresia. This should facilitate prenatal counseling and management of cases with suspected esophageal atresia. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.
Clustering approaches for high‐dimensional databases: A review
Authors: Mittal Mamta , Goyal Lalit M. , Hemanth Duraisamy Jude , Sethi Jasleen K.
Published: January 2019

Data mining is an inevitable task in most of the emerging computing technologies as it debilitates the complexity of datasets by rendering a better insight. Moreover, it entails the efficacy to envisage ingeniously the vast and heterogeneous datasets and thus delineates substantial knowledge from the abundance of data by pragmatic implementation of suitable algorithm. There are galore of algorithms in literature for this purpose. Furthermore, clustering is widely used techniques to analyze the data within the purview of data mining and thus it became as a motivational impetus for the authors to survey the existing literature on this topic rigorously and have consequently identified various key parameters so that concomitant improvement can be possible while selecting a best fit clustering algorithm pertaining to a specific problem domain. Furthermore, clustering, classification and association rule mining are akin and indispensable to data mining and owing to these authors have also included interrelation and intertwining among these terms so that this work will presage chunk of help for the researchers working in this field. The present study also envisages and manifests the challenges associated with the clustering algorithms for two‐ and high‐dimensional databases in a flamboyant fashion. Over and above, this work identifies key parametric attributes to assess the clustering algorithms which in turn benevolent the existing work and paves the way for profound future research in this realm.

This article is categorized under:

Technologies > Structure Discovery and Clustering

Technologies > Classification

Technologies > Association Rules

Fundamental Concepts of Data and Knowledge > Big Data Mining
L-functions for meromorphic modular forms and sum rules in conformal field theory
Authors: McGady David A.
Published: January 2019

Abstract

We define L-functions for meromorphic modular forms that are regular at cusps, and use them to: (i) find new relationships between Hurwitz class numbers and traces of singular moduli, (ii) establish predictions from the physics of T-reflection, and (iii) express central charges in two-dimensional conformal field theories (2d CFT) as a literal sum over the states in the CFTs spectrum. When a modular form has an order-ppole away from cusps, itsq-series coefficients grow asnp−1e2πntfor$$ t\ge \frac{\sqrt{3}}{2} $$t≥32. Its L-function must be regularized. We define such L-functions by a deformed Mellin transform. We study the L-functions of logarithmic derivatives of modular forms. L-functions of logarithmic derivatives of Borcherds products reveal a new relationship between Hurwitz class numbers and traces of singular moduli. If we can write 2d CFT path integrals as infinite products, our L-functions confirm T-reflection predictions and relate central charges to regularized sums over the states in a CFTs spectrum. Equating central charges, which are a proxy for the number of degrees of freedom in a theory, directly to a sum over states in these CFTs is new and relies on our regularization of such sums that generally exhibit exponential (Hagedorn) divergences.
e+e− angularity distributions at NNLL′ accuracy
Authors: Bell Guido , Hornig Andrew , Lee Christopher , Talbert Jim
Published: January 2019

Abstract

We present predictions for the e
+
e
− event shape angularities at NNLL′ resummed and

$$ \mathcal{O}\left({\alpha}_s^2\right) $$

O

α
s
2

matched accuracy and compare them to LEP data at center-of-mass energies Q = 91.2 GeV and Q = 197 GeV. We perform the resummation within the framework of Soft-Collinear Effective Theory, and make use of recent results for the two-loop angularity soft function. We determine the remaining NNLL′ and

$$ \mathcal{O}\left({\alpha}_s^2\right) $$

O

α
s
2

ingredients from a fit to the EVENT2 generator, and implement a shape function with a renormalon-free gap parameter to model non-perturbative effects. Using values of the strong coupling αs(m
Z) and the universal non-perturbative shift parameter Ω1 that are consistent with those obtained in previous fits to the thrust and C-parameter distributions, we find excellent agreement between our predictions and the LEP data for all angularities with a ∈ [−1, 0.5]. This provides a robust test of the predictions of QCD, factorization, and the universal scaling of the non-perturbative shift across different angularities. Promisingly, our results indicate that current degeneracies in the {α

s
(m

Z
), Ω1} parameter space could be alleviated upon fitting these parameters to experimental data for the angularity distributions.
B →P and B →V form factors from B-meson light-cone sum rules beyond leading twist
Authors: Gubernari N. , Kokulu A. , van Dyk D.
Published: January 2019

Abstract

We provide results for the full set of form factors describing semileptonic B-meson transitions to pseudoscalar mesons π, K,

$$ \overline{D} $$

D
¯

and vector mesons ρ, K
∗,

$$ {\overline{D}}^{\ast } $$

D
¯

∗

. Our results are obtained within the framework of QCD Light-Cone Sum Rules with B-meson distribution amplitudes. We recalculate and confirm the results for the leading-twist two-particle contributions in the literature. Furthermore, we calculate and provide new expressions for the two-particle contributions up to twist four. Following new developments for the three-particle distribution amplitudes, we calculate and provide new results for the complete set of three-particle contributions up to twist four. The form factors are computed numerically at several phase space points using up-to-date input parameters, including correlations across phase space points and form factors. We use a model ansatz for all contributing B-meson distribution amplitudes that is self-consistent up to twist-four accuracy. We find that the higher-twist two-particle contributions have a substantial impact on the results, and dominate over the three-particle contributions. Our numerical results, including correlations, are provided as machine-readable files in the supplementary material. We discuss the qualitative phenomenological impact of our results on the present b anomalies.
Convergence of equilibria for bending-torsion models of rods with inhomogeneities
Authors: Pawelczyk Matthäus
Published: January 2019

We prove that, in the limit of vanishing thickness, equilibrium configurations of inhomogeneous, three-dimensional non-linearly elastic rods converge to equilibrium configurations of the variational limit theory. More precisely, we show that, as $h\searrow 0$, stationary points of the energy , for a rod $\Omega _h\subset {\open R}^3$ with cross-sectional diameter h, subconverge to stationary points of the Γ-limit of , provided that the bending energy of the sequence scales appropriately. This generalizes earlier results for homogeneous materials to the case of materials with (not necessarily periodic) inhomogeneities.
Growth in early life and physical and intellectual development at school age: a cohort study
Authors: Li Chao , Zeng Lingxia , Wang Duolao , Allen Stephen , Jaffar Shabbar , Zhou Jing , Chen Tao , Watson Victoria , Yan Hong
Published: January 2019

The associations between growth during early life and subsequent cognitive development and physical outcomes are not widely known in low-resource settings. We examined postnatal weight and height gain through early life and related these measurements to the nutritional status and intellectual development of the same children when they were between 7 and 9 years old. Mothers had enrolled in an randomised controlled trial to evaluate the effect of prenatal micronutrient supplementation on birth weight. Their children were born in 2004, their height and weight were measured at 6, 12, 18 and 24 months of age and were followed up between October 2012 and September 2013 (at ages 7–9 years, n 650). Height-for-age, weight-for-age and BMI-for-age were used to describe the nutritional status, and the Wechsler Intelligence Scale for Children fourth edition was used to measure the intellectual function. Multilevel linear and logistic modelling was used to estimate the association between early growth and subsequent growth and intellectual function. After adjustment, weight gain from 6 to 12 months of age was associated with Full-scale Intelligence Quotient, Verbal Comprehension Index, Working Memory Index and Perceptual Reasoning Index. Weight gain during early life was associated with subsequent nutritional status. For every 1 kg increase in weight during the 0- to 6-month period, the OR for underweight, thinness and stunting at 7–9 years of age were 0·19 (95 % CI 0·09, 0·37), 0·34 (95 % CI 0·19, 0·59) and 0·40 (95 % CI 0·19, 0·83), respectively. Weight gain during the periods of 6–12 months of age and 18–24 months of age was also associated with a lower risk of being underweight. Weight gain during early life was associated with better growth outcomes and improved intellectual development in young school-aged children.
Surgery alone versus post-operative radiotherapy for sinonasal malignant melanoma: a meta-analysis
Authors: Hu R , Yang B-B
Published: January 2019

Objective

Sinonasal malignant melanoma is a relatively rare malignancy with poor prognosis, and effective treatments remain elusive. This analysis aimed to explore whether post-operative radiotherapy conferred any survival advantages in patients with this disease when compared with surgery alone.

Methods

Published studies were identified by searching four electronic databases. The endpoints evaluated were: rates of overall survival, disease-free survival and local control.

Results

Twenty-eight studies including 1392 patients were identified. The results indicated that post-operative radiotherapy led to a significantly better three-year overall survival rate (p= 0.02), and suggested a borderline significant benefit for five-year overall survival (p= 0.05), when compared with surgery alone. However, no statistical advantage was found for disease-free survival, local control or one-year overall survival.

Conclusion

This meta-analysis indicated that adjuvant radiotherapy prolonged survival, but showed no benefit for disease-free survival or local control.
Efficacy of fluoroscopy-guided endoscopic cricopharyngeal myotomy
Authors: Fujiwara K , Kawamoto K , Taira K , Fukuhara T , Koyama S , Kataoka H , Kitano H , Takeuchi H
Published: January 2019

Background

In endoscopic cricopharyngeal myotomy, surgeons sometimes have concerns about performing an adequate incision with only a narrow intra-cavital view from one direction. In order to overcome these issues, fluoroscopic radiography was used during endoscopic cricopharyngeal myotomy.

Methods

Peri-operative fluoroscopic radiography was utilised to check the position of the diverticuloscope, and to confirm the extent of the incision during surgery. A balloon catheter was used to determine whether the cricopharyngeal muscle was sufficiently resected. Blood loss, peri-operative complications, and functional oral swallowing scale and penetration aspiration scale scores were evaluated.

Results

In 12 out of 15 patients, intra-operative fluoroscopic radiography showed the diverticuloscope positioned in the post-cricoid area, and the cricopharyngeal muscle was raised and the surgery completed without adverse effect. Swallowing functions improved following surgery.

Conclusion

Intra-operative fluoroscopy might improve endoscopic cricopharyngeal myotomy by allowing surgeons to confirm the extent of resection, and by reducing peri-operative morbidity and complication rates.
Förderung biologischer Beobachtungskompetenz im Kindergarten
Authors: Klemm Janina , Kohlhauf Lucia , Boone William J. , Sodian Beate , Neuhaus Birgit J.
Published: January 2019

Zusammenfassung. Beobachten ist eine zentrale wissenschaftliche Erkenntnismethode, die gerade für Vorschulkinder einen guten Einstieg in naturwissenschaftliches Lernen bietet ( de Bóo, 2006 ; Johnston, 2009 ; Kohlhauf, 2013 ). Da biologische Förderung im Vorschulbereich bisher meist unsystematisch abläuft ( Kohlhauf, 2013 ), war es Ziel der hier beschriebenen Studie, zu untersuchen, ob die biologische Beobachtungskompetenz von Vorschulkindern mit einem eigens dafür entwickelten Trainingsprogramm systematisch gefördert werden kann. 75 Kinder im Vorschulalter (Alter: 4;9 bis 6;7 Jahre) nahmen an der Studie teil. Während die 40 Kinder der Experimentalgruppe ein Trainingsprogramm durchliefen, das darauf abzielte, die Wahrnehmung und Beschreibung von Details, das wissenschaftliche Denken und die Interpretation beobachteter Zusammenhänge zu verbessern, erhielt die Kontrollgruppe keine spezielle Förderung der Beobachtungskompetenz. Vor und nach dem Training wurde die Beobachtungskompetenz aller beteiligter Kinder gemessen. Die Trainingsmaterialien konnten von den Trainer_innen laut Selbsteinschätzung gut angewendet werden, waren laut Trainer_innen für die Altersgruppe geeignet und motivierten die Kinder dazu, sich aktiv zu beteiligen. Allerdings beeinflussten die Trainingseinheiten die Beobachtungskompetenz der Kinder aus der Experimentalgruppe unterschiedlich stark: Während die Kinder, die zu Beginn des Trainings bereits bessere Beobachter waren, von dem Training profitierten, konnten die schwächeren Kinder ihre Beobachtungskompetenz nach Absolvierung der Einheiten nicht steigern.
Mineral‐Filled Fractures as Indicators of Multigenerational Fluid Flow in the Pahrump Hills Member of the Murray Formation, Gale Crater, Mars
Authors: Kronyak R. E. , Kah L. C. , Edgett K. S. , VanBommel S. J. , Thompson L. M. , Wiens R. C. , Sun V. Z. , Nachon M.
Published: January 2019

Mineral‐filled fractures (veins) are valuable indicators of deformation and fluid flow within a sedimentary package. Information obtained from vein morphology, texture, and chemistry may elucidate the sequence and nature of postdepositional fluid events. Additional information from vein patterns and interactions between veins and host rock provides insight into fracture formation mechanism(s). The widespread occurrence of veins and other diagenetic features in the sedimentary rock record preserved in Gale crater, Mars, indicates that postdepositional fluids were regionally active considerably later in time than the primary fluviolacustrine environments responsible for the deposition of Mount Sharp strata. Here we report a suite of veins within the Murray formation at the Pahrump Hills locality that were investigated using the scientific payload of the Mars Science Laboratory Curiosity rover. Based on an analysis of vein color, morphology, and texture, and corroborated by vein chemistry, we interpret three distinct vein types at Pahrump Hills: gray veins, white veins, and dark‐toned veins. These veins represent distinct, separate episodes of postdepositional fluid flow, suggesting a protracted history of fluid stability in Gale crater. Additionally, we utilize vein patterns across multiple lithologies at the Pahrump Hills field site to suggest hydrofracture as the primary mechanism of fracture formation.
Masked Shoreline Erosion at Large Spatial Scales as a Collective Effect of Beach Nourishment
Authors: Armstrong Scott B. , Lazarus Eli D.
Published: January 2019

Sea‐level rise along low‐lying coasts of the world's passive continental margins should, on average, drive net shoreline retreat over large spatial scales (>102 km). A variety of natural physical factors can influence trends of shoreline erosion and accretion, but trends in recent rates of shoreline change along the U.S. Atlantic Coast reflect an especially puzzling increase in accretion, not erosion. A plausible explanation for the apparent disconnect between environmental forcing and shoreline response along the U.S. Atlantic Coast is the application, since the 1960s, of beach nourishment as the predominant form of mitigation against chronic coastal erosion. Using U.S. Geological Survey shoreline records from 1830–2007 spanning more than 2,500 km of the U.S. Atlantic Coast, we calculate a mean rate of shoreline change, prior to 1960, of −55 cm/year (a negative rate denotes erosion). After 1960, the mean rate reverses to approximately +5 cm/year, indicating widespread apparent accretion despite steady (and, in some places, accelerated) sea‐level rise over the same period. Cumulative sediment input from decades of beach‐nourishment projects may have sufficiently altered shoreline position to mask “true” rates of shoreline change. Our analysis suggests that long‐term rates of shoreline change typically used to assess coastal hazard may be systematically underestimated. We also suggest that the overall effect of beach nourishment along of the U.S. Atlantic Coast is extensive enough to constitute a quantitative signature of coastal geoengineering and may serve as a bellwether for nourishment‐dominated shorelines elsewhere in the world.
Mechanisms of Low‐Frequency Oxygen Variability in the North Pacific
Authors: Ito Takamitsu , Long Matthew C. , Deutsch Curtis , Minobe Shoshiro , Sun Daoxun
Published: January 2019

This study investigates the mechanisms of interannual and decadal variability of dissolved oxygen (O2) in the North Pacific using historical observations and a hindcast simulation using the Community Earth System Model. The simulated variability of upper ocean (200 m) O2 is moderately correlated with observations where sampling density is relatively high. The dominant mode of O2 variability explains 24.8% of the variance and is significantly correlated with the Pacific Decadal Oscillation (PDO) index (r = 0.68). Two primary mechanisms are hypothesized by which the PDO controls upper ocean O2 variability. Vertical movement of isopycnals (“heave”) drives O2 variations in the deep tropics; isopycnal surfaces are depressed in the eastern tropics under the positive (El Niño‐like) phase of PDO, leading to O2 increases in the upper water column. In contrast to the tropics, changes in subduction are the primary control on extratropical O2 variability. These hypotheses are tested by contrasting O2 anomalies with the heave‐induced component of variability calculated from potential density anomalies. Isopycnal heave is the leading control on O2 variability in the tropics, but heave alone cannot fully explain the amplitude of tropical O2 variability, likely indicating reinforcing changes from the biological O2 consumption. Midlatitude O2 variability indeed reflects ocean ventilation downstream of the subduction region where O2 anomalies are correlated with the depth of winter mixed layer. These mechanisms, synchronized with the PDO, yield a basin‐scale pattern of O2 variability that are comparable in magnitude to the projected rates of ocean deoxygenation in this century under “unchecked” emission scenario.
Modeling the Recent Changes in the Arctic Ocean CO2Sink (2006–2013)
Authors: Manizza Manfredi , Menemenlis Dimitris , Zhang Hong , Miller Charles E.
Published: January 2019

The Arctic Ocean (AO) and its associated marginal seas have recently experienced rapid climate and environmental changes, most notably sea‐ice area (SIA) loss and warming potentially impacting its uptake of carbon dioxide (CO2). We used the state‐of‐the‐art ECCO2‐Darwin coupled ocean‐biogeochemistry model to simulate the 2006–2013 period and investigate the impact of changing SIA on the CO2uptake of the AO. We find that the mean annual CO2sink of the AO is 153 ± 14 TgC a−1and the CO2sink decreased at a rate of 3.6 TgC a−1even though SIA decreased by 8 × 104 km2 a−1over the same period. Extreme SIA loss in 2007 resulted in a 185.4 TgC CO2sink, an increase ∼20% over the 2006–2013 mean. In contrast, extreme SIA loss of 2012 resulted in a CO2sink of the AO of only 146.3 TgC due to two main factors: (1) increased both wind speed and stratification in the Eastern Siberian Sea absorbing less CO2and (2) decreased primary production and area of air‐sea gas exchange in the Chukchi and Nordic Seas. Our model captures a trend of decreasing CO2sink in most of the Chukchi Sea during fall but does not show the changes in winter CO2sink in the Nordic and Barents Seas as previous independent studies have suggested. Our results indicate that future AO‐atmosphere CO2exchange will be determined by complex interplay of SIA and other environmental drivers.
Rapid Exhumation of Earth's Youngest Exposed Granites Driven by Subduction of an Oceanic Arc
Authors: Spencer C. J. , Danišík M. , Ito H. , Hoiland C. , Tapster S. , Jeon H. , McDonald B. , Evans N. J.
Published: January 2019

Exhumation of plutonic systems is driven by a range of mechanisms including isostatic, tectonic, and erosional processes. Variable rates of plutonic exhumation in active subduction systems may be driven by idiosyncrasies of regional geology or by first‐order tectonic features. We report new age, isotope, and low‐temperature thermochronology constraints of granitoids from the Hida Mountains of central Japan that constrain the highest rates and magnitude of plutonic rock exhumation within the Japan and one of the highest worldwide. This extreme exhumation is centered on the apex of a lithospheric scale anticlinorium associated with the subduction of the Izu‐Bonin oceanic arc. The spatial and temporal relationship between the exhumation of these Pleistocene plutons and the subducting/accreting Izu‐Bonin oceanic arc links the plate‐scale geodynamics and regional exhumation patterns. Identifying thermochronological anomalies within magmatic arcs provides an opportunity to identify ancient asperities previously subducted and responsible for rapid exhumation rates within ancient subduction systems.
Seafloor Geodesy Revealed Partial Creep of the North Anatolian Fault Submerged in the Sea of Marmara
Authors: Yamamoto Ryusuke , Kido Motoyuki , Ohta Yusaku , Takahashi Narumi , Yamamoto Yojiro , Pinar Ali , Kalafat Doğan , Özener Haluk , Kaneda Yoshiyuki
Published: January 2019

In this study, the creep rate across the North Anatolian Fault was directly measured in the western Sea of Marmara using the seafloor acoustic ranging technique; the data reveal coupling conditions on the fault interface and stress accumulation with implications for regional seismic risk evaluation. Continuous measurements over a period of 3.5 years at a site in the Western High clearly indicate right‐lateral displacement at a rate of 10.7 ± 4.7 mm/year (95% confidence level); approximately half of the regional block motion at this location is released by this steady motion. A simple model of three elastic layers—a partially creeping sedimentary layer (8 km) at the top with the observed rate, a locked (3 km) and fully creeping layer in the middle, and a bottom layer—assumed from seismicity, reasonably explains onshore Global Navigation Satellite System data for the surrounding region.
Potential Increase in Hazard From Mediterranean Hurricane Activity With Global Warming
Authors: González‐Alemán Juan J. , Pascale Salvatore , Gutierrez‐Fernandez Jesús , Murakami Hiroyuki , Gaertner Miguel A. , Vecchi Gabriel A.
Published: January 2019

Mediterranean hurricanes (Medicanes) are intense cyclones that acquire tropical characteristics, associated with extreme winds and rainfall, thus posing a serious natural hazard to populated areas along Mediterranean coasts. Understanding how Medicanes will change with global warming remains, however, a challenge, because coarse resolution and/or the lack of atmosphere‐ocean coupling limit the reliability of numerical simulations. Here we investigate the Medicanes' response to global warming using a recently developed 25‐km global coupled climate model, which features a realistic representation of Medicanes in present climate conditions. It is found that despite a decrease in frequency, Medicanes potentially become more hazardous in the late century, lasting longer and producing stronger winds and rainfall. These changes are associated with a more robust hurricane‐like structure and are mainly confined to autumn. Thus, continued anthropogenic warming will increase the risks associated with Medicanes even in an intermediate scenario (Representative Concentration Pathway, RCP4.5), with potential natural and socioeconomic consequences.
Climatic Warming Increases Spatial Synchrony in Spring Vegetation Phenology Across the Northern Hemisphere
Authors: Liu Qiang , Piao Shilong , Fu Yongshuo H. , Gao Mengdi , Peñuelas Josep , Janssens Ivan A.
Published: January 2019

Climatic warming has advanced spring phenology across the Northern Hemisphere, but the spatial variability in temperature sensitivity of spring phenology is substantial. Whether spring phenology will continue to advance uniformly at latitudes has not yet been investigated. We used Bayesian model averaging and four spring phenology models, and demonstrated that the start of vegetation growing season across the Northern Hemisphere will become substantially more synchronous (up to 11.3%) under future climatic warming conditions. Larger start of growing season advances are expected at higher than lower latitudes (3.7–10.9 days earlier) due to both larger rate in spring warming at higher latitudes and larger decreases in the temperature sensitivity of start of growing season at low latitudes. The consequent impacts on the northern ecosystems due to this increased synchrony may be considerable and thus worth investigating.
A Study of the F2 Layer Stratification on Ionograms Using a Simple Model of TIDs
Authors: Jiang Chunhua , Yang Guobin , Liu Jing , Zhao Zhengyu
Published: January 2019

To study the effect of gravity waves/traveling ionospheric disturbances (TIDs) on ionograms with the F2 layer stratification, we reconstructed ionograms using a simple of TIDs model through a ray tracing method. Results show that two typical types of the F2 layer stratification induced by gravity waves/TIDs could be synthesized on ionograms by the simple model of TIDs in this study. Furthermore, we found that vertical and horizontal gradients caused by TIDs could cause different features on ionograms. Results suggested that the vertical gradient induced by gravity waves/TIDs could cause the F2 stratification. The horizontal gradient caused by gravity waves/TIDs might play a significant role in forming spread F on ionograms. Moreover, we found that the smaller wavelength and larger periodical time of TIDs could make it easier to form the F2 layer stratification on ionograms through modeling studies.
Cosmic Noise Absorption During Solar Proton Events in WACCM‐D and Riometer Observations
Authors: Heino Erkka , Verronen Pekka T. , Kero Antti , Kalakoski Niilo , Partamies Noora
Published: January 2019

Solar proton events (SPEs) cause large‐scale ionization in the middle atmosphere leading to ozone loss and changes in the energy budget of the middle atmosphere. The accurate implementation of SPEs and other particle ionization sources in climate models is necessary to understand the role of energetic particle precipitation in climate variability. We use riometer observations from 16 riometer stations and the Whole Atmosphere Community Climate Model with added D region ion chemistry (WACCM‐D) to study the spatial and temporal extent of cosmic noise absorption (CNA) during 62 SPEs from 2000 to 2005. We also present a correction method for the nonlinear response of observed CNA during intense absorption events. We find that WACCM‐D can reproduce the observed CNA well with some need for future improvement and testing of the used energetic particle precipitation forcing. The average absolute difference between the model and the observations is found to be less than 0.5 dB poleward of about 66° geomagnetic latitude, and increasing with decreasing latitude to about 1 dB equatorward of about 66° geomagnetic latitude. The differences are largest during twilight conditions where the modeled changes in CNA are more abrupt compared to observations. An overestimation of about 1° to 3° geomagnetic latitude in the extent of the CNA is observed due to the fixed proton cutoff latitude in the model. An unexplained underestimation of CNA by the model during sunlit conditions is observed at stations within the polar cap during 18 of the studied events.
Seismic Tremor Reveals Spatial Organization and Temporal Changes of Subglacial Water System
Authors: Vore Margot E. , Bartholomaus Timothy C. , Winberry J. Paul , Walter Jacob I. , Amundson Jason M.
Published: January 2019

Subglacial water flow impacts glacier dynamics and shapes the subglacial environment. However, due to the challenges of observing glacier beds, the spatial organization of subglacial water systems and the time scales of conduit evolution and migration are largely unknown. To address these questions, we analyze 1.5‐ to 10‐Hz seismic tremor that we associate with subglacial water flow, hat is, glaciohydraulic tremor, at Taku Glacier, Alaska, throughout the 2016 melt season. We use frequency‐dependent polarization analysis to estimate glaciohydraulic tremor propagation direction (related to the subglacial conduit location) and a degree day melt model to monitor variations in melt‐water input. We suggest that conduit formation requires sustained water input and that multiconduit flow paths can be distinguished from single‐conduit flow paths. Theoretical analysis supports our seismic interpretations that subglacial discharge likely flows through a single‐conduit in regions of steep hydraulic potential gradients but may be distributed among multiple conduits in regions with shallower potential gradients. Seismic tremor in regions with multiple conduits evolves through abrupt jumps between stable configurations that last 3–7 days, while tremor produced by single‐conduit flow remains more stationary. We also find that polarized glaciohydraulic tremor wave types are potentially linked to the distance from source to station and that multiple peak frequencies propagate from a similar direction. Tremor appears undetectable at distances beyond 2–6 km from the source. This new understanding of the spatial organization and temporal development of subglacial conduits informs our understanding of dynamism within the subglacial hydrologic system.
Transport Scaling of Dune Dimensions in Shallow Flows
Authors: Bradley Ryan W. , Venditti Jeremy G.
Published: January 2019

Dune dimensions in sand‐bedded rivers are often thought to scale with flow depth (h), with height (H) scaling as 1/6h and length (L) as 5h, even though substantial scatter about the relations has been observed. Transport stage has been shown to affect bedform geometry, but this control is often ignored in favor of depth scaling relations. Here, we use a series of flume experiments to systematically test controls on dune dimensions and variability. Experiments involved three sets of runs under five constant transport stages, ranging threshold to washout conditions, at three different flow depths. The mobile bed was repeatedly scanned during a 10‐hr equilibrium period to derive mean values and quantify the variability. The results show that dune‐depth scaling is not consistent because of a transport stage effect. Dune height increases with transport stage until a point when H decreases. Length remains nearly constant with transport stage until further increases in transport stage leads to lengthening. In general, dunes grow higher when significant bedload transport occurs but become flatter and longer in the presence of substantial suspension. Ultimately, dunes scale with transport stage, which is a function of slope, grain size, and h. The results are used to derive transport stage relations to guide predictions of dune dimensions in rivers and reconstructions of paleoflows based on dimensions estimated from cross strata. The relations incorporate the nonlinear response of dune dimensions with transport stage and provide metrics of uncertainty to include in predictions.
A Seasonal to Interannual View of Inorganic and Organic Carbon and pH in Western Lake Superior
Authors: Minor Elizabeth C. , Tennant Cody James , Brown Erik T.
Published: January 2019

To investigate the carbon cycle of Lake Superior, Earth's largest freshwater lake by surface area, we performed total organic carbon, dissolved organic carbon, chlorophyll, spectrophotometric pH, total inorganic carbon, and alkalinity measurements on seasonal samples from the western lake. The last three parameters, along with in situ temperature, were used to calculate the partial pressure of carbon dioxide in surface water (pCO2(w)) using the CO2SYS algorithm. There was a strong positive correlation between pH and water temperature and a weaker but significant positive correlation between pH and chlorophyll concentration. Total organic carbon exhibited higher nearshore concentrations (as determined by a negative correlation with total water column depth); such a spatial relationship did not appear in the inorganic carbon parameters (total inorganic carbon, pH, or pCO2(w)). Western Lake Superior exhibited net outgassing in spring, little net gas transfer in summer, and some outgassing in the fall. The pCO2(w) values were negatively correlated with both water temperature and chlorophyll concentration. Seasonal differences in pCO2(w) in Lake Superior appeared more strongly driven by biology and terrestrial inputs as compared to direct effects of temperature on CO2 solubility. Interannual data from the long‐term Great Lakes Environmental Database data set indicated that lake alkalinity has been increasing over the past 20 years, and lake surface water pH appeared relatively stable. Modeling pH change over the same time frame in CO2SYS shows that increases in alkalinity and lake surface water temperature counteract the increase in atmospheric carbon dioxide concentration, leading to a relatively constant pH, consistent with observational data.
Evaluating the Representation of Vegetation Phenology in the Community Land Model 4.5 in a Temperate Grassland
Authors: Zhang Lexin , Lei Huimin , Shen Hong , Cong Zhentao , Yang Dawen , Liu Tingxi
Published: January 2019

Vegetation plays an important role in terrestrial ecosystems and affects both water and carbon cycles. It is crucial to predict vegetation phenology accurately to understand the Earth's ecosystems better. In this study, we evaluated the temperate grassland phenology simulated by the Community Land Model 4.5 for the Northeast China Transect with the Moderate Resolution Imaging Spectroradiometer leaf area index (LAI) data set. Results show that although the CLM could partly capture the seasonal patterns of LAI for temperate grasslands, shortcomings lie in a delayed end date of growing season and a problematic senescence existed in early summer. The reason is attributed to the low temperature threshold set for leaf offset and an inaccurate carbon allocation strategy for its display and storage. With the adjusted key phenology parameters, the modeled temperate grassland phenology has been substantially improved for this system: An overestimation of the growing‐season LAI as well as the annual gross primary productivity can be constrained. Meanwhile, the modified phenology would effectively change the partition of evapotranspiration in a more reasonable pattern.
Ambient Noise Tomography Across the Taiwan Strait, Taiwan Island, and Southwestern Ryukyu Arc: Implications for Subsurface Slab Interactions
Authors: Ai Sanxi , Zheng Yong , Xiong Cheng
Published: January 2019

The subduction flipping in the Taiwan region leads to complexities in the lithospheric structure. To better understand the arc‐continental collision process in this zone, we construct a 3‐D lithospheric model of the Taiwan Strait, Taiwan Island, and southwestern Ryukyu Arc. In the middle to lower crust, low velocities are mainly located beneath the Ryukyu Trough and the rifted basins in the Taiwan Strait, and high velocities are imaged in the Kuanyin and Penghu Platforms. Likely, the Kuanyin and Penghu Platforms act as relatively strong barriers that block the persistent westward advance of the western deformation front of the Taiwan mountain belt, as manifested by shape of the deformation front that withdraws to the east in the basement highs. In the mantle, high velocities are observed beneath the Central Range and Ryukyu Arc, which is interpreted as the two oppositely oriented slab subductions, that is, subduction of the Philippine Sea slab in the northeast Taiwan and Eurasian slab subduction in south Taiwan. Based on the vertical transects through our 3‐D model, we find that the subduction polarity has flipped in north Taiwan, and the tectonic framework in central Taiwan is in the process of subduction polarity reversal. We also image significant low mantle velocities beneath the North Taiwan Volcanic Zone and Taihsi Basin, which may be related to the breakoff of the subducting Eurasian slab. In addition, we propose that the inherited weakness of the Taihsi Basin may have facilitated the slab breakoff in central Taiwan.
Ouattara Receives 2018 Africa Award for Research Excellence in Space Science
Authors:   AGU
Published: January 2019

Fr�d�ric Ouattara received the Africa Award for Research Excellence in Space Science at the 2018 AGU Fall Meeting Honors Ceremony, held 12 December 2018 in Washington, D. C. The award recognizes an individual “for completing significant work that shows the focus and promise of making outstanding contributions to research in space science.”
Exploring Uncertainty in Streamflow Estimates
Authors: Sidder Aaron
Published: January 2019

A review of streamflow uncertainty estimation methods reveals that one method does not fit all situations and provides recommendations for how to improve streamflow estimates.
Next Olympics Marathon Course Has Dangerous “Hot Spots” for Spectators
Authors: Kornei Katherine
Published: January 2019

Spectators’ health may be jeopardized by high heat loads along the 2020 Olympics marathon course in Tokyo, a bicycle-mounted meteorological survey found.
Correction: Control of PD-L1 expression by miR-140/142/340/383 and oncogenic activation of the OCT4–miR-18a pathway in cervical cancer
Authors: Dong Peixin , Xiong Ying , Yu Jiehai , Chen Lin , Tao Tang , Yi Song , Hanley Sharon J. B. , Yue Junming , Watari Hidemichi , Sakuragi Noriaki
Published: January 2019

In Fig. 2d, the Western blot panels representing GAPDH endogenous loading controls were improperly cropped, leading to four lanes of GAPDH endogenous loading controls for five lanes of PD-L1 protein expressions. The authors apologize for any confusion that this error may have caused. This has now been corrected in both the PDF and HTML versions of the article.
Floquet group theory and its application to selection rules in harmonic generation
Authors: Neufeld Ofer , Podolsky Daniel , Cohen Oren
Published: January 2019

Symmetry is one of the most generic and useful concepts in science, often leading to conservation laws and selection rules. Here we formulate a general group theory for dynamical symmetries (DSs) in time-periodic Floquet systems, and derive their correspondence to observable selection rules. We apply the theory to harmonic generation, deriving closed-form tables linking DSs of the driving laser and medium (gas, liquid, or solid) in (2+1)D and (3+1)D geometries to the allowed and forbidden harmonic orders and their polarizations. We identify symmetries, including time-reversal-based, reflection-based, and elliptical-based DSs, which lead to selection rules that are not explained by currently known conservation laws. We expect the theory to be useful for ultrafast high harmonic symmetry-breaking spectroscopy, as well as in various other systems such as Floquet topological insulators.
A child with perinatal HIV infection and long-term sustained virological control following antiretroviral treatment cessation
Authors: Violari Avy , Cotton Mark F. , Kuhn Louise , Schramm Diana B. , Paximadis Maria , Loubser Shayne , Shalekoff Sharon , Da Costa Dias Bianca , Otwombe Kennedy , Liberty Afaaf , McIntyre James , Babiker Abdel , Gibb Diana , Tiemessen Caroline T.
Published: January 2019

Understanding HIV remission in rare individuals who initiated antiretroviral therapy (ART) soon after infection and then discontinued, may inform HIV cure interventions. Here we describe features of virus and host of a perinatally HIV-1 infected child with long-term sustained virological control. The child received early limited ART in the Children with HIV Early antiRetroviral therapy (CHER) trial. At age 9.5 years, diagnostic tests for HIV are negative and the child has characteristics similar to uninfected children that include a high CD4:CD8 ratio, low T cell activation and low CCR5 expression. Virus persistence (HIV-1 DNA and plasma RNA) is confirmed with sensitive methods, but replication-competent virus is not detected. The child has weak HIV-specific antibody and T cell responses. Furthermore, we determine his HLA and KIR genotypes. This case aids in understanding post-treatment control and may help design of future intervention strategies.
Usp7 regulates Hippo pathway through deubiquitinating the transcriptional coactivator Yorkie
Authors: Sun Xiaohan , Ding Yan , Zhan Meixiao , Li Yan , Gao Dongqing , Wang Guiping , Gao Yang , Li Yong , Wu Shian , Lu Ligong , Liu Qingxin , Zhou Zizhang
Published: January 2019

The Hippo pathway plays an important role in organ development and adult tissue homeostasis, and its deregulation has been implicated in many cancers. The Hippo signaling relies on a core kinase cascade culminating in phosphorylation of the transcription coactivator Yorkie (Yki). Although Yki is the key effector of Hippo pathway, the regulation of its protein stability is still unclear. Here, we show that Hippo pathway attenuates the binding of a ubiquitin-specific protease Usp7 to Yki, which regulates Hippo signaling through deubiquitinating Yki. Furthermore, the mammalian homolog of Usp7, HAUSP plays a conserved role in regulating Hippo pathway by modulating Yap ubiquitination and degradation. Finally, we find that the expression of HAUSP is positively correlated with that of Yap, both showing upregulated levels in clinical hepatocellular carcinoma (HCC) specimens. In summary, our findings demonstrate that Yki/Yap is stabilized by Usp7/HAUSP, and provide HAUSP as a potential therapeutic target for HCC.
γ-Aminobutyric Acid Promotes Chloroplast Ultrastructure, Antioxidant Capacity, and Growth of Waterlogged Maize Seedlings
Authors: Salah Akram , Zhan Ming , Cao Cougui , Han Yuling , Ling Lin , Liu Zhihui , Li Ping , Ye Miao , Jiang Yang
Published: January 2019

γ-aminobutyric acid (GABA) is a small signaling molecule that accumulates rapidly in plants exposed to various stresses; however, it has not been applied in regulating waterlogging tolerance in maize seedlings. Here, the effect of exogenous application of GABA in the determined optimal concentration was performed on seedlings of two maize cultivars under waterlogging treatments initiated at 3-leaf (V3) and 5-leaf stages (V5) in repeated experiments in 2016 and 2017. Chloroplast ultrastructure, photosynthesis, antioxidant capacity, and reactive oxygen species (ROS) production in the leaves were examined and compared with the corresponding values under normal soil water treatment (CK) and waterlogging treatment (WL). Compared with WL treatment, application of GABA significantly increased aboveground and root dry matter by 19.0% and 61.0%, promoted photosynthetic rate and chlorophyll content by 19.8% and 36.0%, increased the number of grana per chloroplast by 36.0%, fortified antioxidants (SOD, POD, CAT, GR, APX, VC) activities by 14.7–42.7%, and reduced the content of MDA, H2O2, and O2− by 30.5%, 32.5%, and 21.8%, respectively (p < 0.05). Collectively, GABA application was shown to promote the growth of maize seedlings under waterlogging, by down regulating ROIs-producing enzymes, activating antioxidant defense systems, and improving chloroplast ultrastructure and photosynthetic traits.