bluuebunny/crossref_metadata_2025 huggingface dataset:
Medical and financial burden of acute intermittent porphyria
Authors: Neeleman Rochus A. , Wagenmakers Margreet A. E. M. , Koole‐Lesuis Rita H. , Mijnhout G. Sophie , Wilson J. H. Paul , Friesema Edith C. H. , Langendonk Janneke G.
Published: April 2018

Introduction

A small proportion of patients with acute intermittent porphyria (AIP) suffer from recurrent porphyric attacks, with a severely diminished quality of life. In this retrospective case‐control study, the burden of disease is quantified and compared among three AIP patient subgroups: cases with recurrent attacks, cases with one or occasional attacks and asymptomatic carriers.

Methods

Data from patient records and questionnaires were collected in patients between 1960 and 2016 at the Erasmus Medical Center, Rotterdam, the Netherlands. We collected symptoms related to porphyria, porphyria related complications, attack frequency, hospitalisation frequency, hospitalisation days related to acute porphyric attacks, frequency of heme infusions and medical healthcare costs based on hospitalisations and heme therapy.

Results

In total 11 recurrent AIP cases, 24 symptomatic AIP cases and 53 AIP carriers as controls were included. All recurrent patients reported porphyria related symptoms, such as pain, neurological and/or psychiatric disorders, and nearly all developed complications, such as hypertension and chronic kidney disease. In the recurrent cases group, the median lifelong number of hospitalisation days related to porphyric attacks was 82 days per patient (range 10–374), and they spent a median of 346 days (range 34–945) at a day‐care facility for prophylactic heme therapy; total follow‐up time was 243 person‐years (PYRS). In the symptomatic non‐recurrent group the median lifelong number of hospitalisation days related to porphyric attacks was 7 days per patient (range 1–78), total follow‐up time was 528 PYRS. The calculated total medical healthcare cost for recurrent cases group was €5.8 million versus €0.3 million for the symptomatic cases group.
Finite element simulation and experimental test of the wear behavior for self-lubricating spherical plain bearings
Authors: Xue Yahong , Chen Jigang , Guo Sumin , Meng Qingliang , Luo Junting
Published: April 2018

In this study, based on the classical Archard adhesion wear theory, a three-dimensional finite element model was established, with the aim of simulating the failure process of self-lubricating spherical plain bearings in the swinging wear condition. The results show that the self-lubricating spherical plain bearings go through two different stages during the wear process, namely, initial wear stage and stable wear stage. Because the large contact points wear out during the initial wear stage, the maximum contact pressure decreases as the test period increases. The relatively larger wear depth region shows elliptical distribution, and the maximum distribution appears in the central contact area. The wear depth reaches 0.974 mm after swinging 25,000 times. PTFE fibers, which possess a good friction performance but poor abrasion resistance, abundantly exist on the friction surfaces of the fabric liner. Consequently, the friction torque during the initial wear stage is slightly smaller than the friction torque during the stable wear stage; however, the wear rate during the initial wear stage is high. The reliability and effectiveness of the finite element model are verified by experiment. The developed finite element model can be used for the analysis of the wear mechanisms of bearings and the prediction of the service life of bearings.
SELENIUM BIOFORTIFICATION OF RICE THROUGH FOLIAR APPLICATION WITH SELENITE AND SELENATE
Authors: LIDON FERNANDO CEBOLA , OLIVEIRA KARLIANA , GALHANO CARLOS , GUERRA MAURO , RIBEIRO MARIA MANUELA , PELICA JOÃO , PATACO INÊS , RAMALHO JOSÉ COCHICHO , LEITÃO ANTÓNIO EDUARDO , ALMEIDA ANA SOFIA , CAMPOS PAULA SCOTTI , RIBEIRO-BARROS ANA I. , PAIS ISABEL P. , SILVA MARIA MANUELA , CARVALHO MARIA LUISA , SANTOS JOSÉ PAULO , PESSOA MARIA FERNANDA , REBOREDO FERNANDO HENRIQUE
Published: April 2018

Selenium (Se) is an essential micronutrient for humans, yet its dietary intake is low, mostly due to the low bioavailability in soils and therefore in edible plant tissues. To overcome Se deficiency, the breeding approach (i.e., genetic biofortification), namely in rice, is largely dependent on available Se pools. To ensure the success of genetic biofortification with Se, agronomic biofortification can be accomplished through foliar Se application. Considering this background, the main hypothesis of this work was centered in the foliar application of Se to attain agronomic biofortification of rice crops. This study also aimed to assess the full potential for increasing grain Se concentrations during rice filling, as well as the types of nutrients deposition. An experimental design applying two foliar fertilizers (sodium selenite and sodium selenate) was developed. As test systems, four rice genotypes (Ariete, Albatros, OP1105 and OP1109) were used and the kinetics of micro- and macro-nutrients accumulation and deposition were assessed. Biofortification was performed in field trials for two years with foliar fertilization ranging between 0 and 300 g Se ha−1. At the end of the plant cycle, selenite applications triggered 427- to 884-fold increases in grain Se concentrations among rice genotypes (Albatros > OP1105 > OP1109 > Ariete). The application of selenate also prompted 128- to 347-fold increases in grain Se concentrations in rice crops (Albatros > OP1105 > Ariete > OP1109). Regardless of the foliar fertilizer applied, Se deposition among genotypes occurred throughout the grain without relevant inhibitory effects on yields. In each genotype, micro and macronutrients varied among crop tissues.
The Ceremonial Reception of Medieval Papal Legates
Authors: RENNIE KRISTON R.
Published: April 2018

This article examines the ceremonial reception of papal legates in the early Middle Ages. It offers a precise, distinctive and normative portrait of their ritualised practice well before the existence of written canonical rules and procedures. The customs, principles, gestures and symbols conditioning legatine activities in this historical era became necessary pre-conditions to political communication, interaction and exchange. Their expression and representation, it is argued, help to explain the manifestation of Roman authority in distant Christian provinces, its varied meaning to contemporaries and the formative rules of political governance and diplomacy.
Comparative in vitro efficacy of kefir produced from camel, goat, ewe and cow milk on Haemonchus contortus
Authors: Alimi D. , Rekik M. , Akkari H.
Published: April 2018

One of the great challenges of veterinary parasitology is the search for alternative methods for controlling gastrointestinal parasites in small ruminants. Milk kefir is a traditional source of probiotic, with great therapeutic potential. The objective of this study was to investigate the anthelmintic effects of kefir on the abomasal nematode Haemonchus contortus from sheep. The study used camel, goat, ewe and cow milk as a starting material, to produce camel, goat, cow and ewe milk kefir. All kefirs showed a significant concentration-dependent effect on H. contortus egg hatching at all tested concentrations. The highest inhibition (100%) of eggs was observed with camel milk kefir at a concentration 0.125 mg/ml. In relation to the effect of kefirs on the survival of adult parasites, all kefirs induced concentration-dependent mortality in adults, with variable results. The complete mortality (100%) of adults of H. contortus occurred at concentrations in the range 0.25–2 mg/ml. The highest inhibition of motility (100%) of worms was observed after 8 h post exposure with camel milk kefir at 0.25 mg/ml. These findings indicate that kefir can be considered a potential tool to control haemonchosis in sheep. Further investigations are needed to assess the active molecules in kefir responsible for its anthelmintic properties and to investigate similar in vivo effects.
Phylogenetic relationships of three tribes of cloacinine nematodes (Strongylida: Chabertiidae) from macropodid marsupials
Authors: Chilton N.B. , Huby-Chilton F. , Koehler A. , Gasser R.B. , Beveridge I.
Published: April 2018

The phylogenetic relationships of 42 species of cloacinine nematodes belonging to three tribes (Coronostrongylinea, Macropostrongylinea and Zoniolaiminea) were examined based on sequence data of the first and second internal transcribed spacers (ITS-1 and ITS-2) of the nuclear ribosomal DNA. All nematodes examined are parasites of Australian macropodid marsupials. None of the three nematode tribes was monophyletic. Paraphyly was also encountered in three genera:Papillostrongylus,MonilonemaandWallabinema. Species within the genusThallostonemawere limited to a single host genus (i.e.Thylogale), whereas species within the five principal genera (Coronostrongylus,Macropostrongylus,Popovastrongylus,WallabinemaandZoniolaimus) were found to occur in multiple host genera. Potential modes of evolution among these nematodes are discussed.
Catherine Zuckert on Machiavelli's New Understanding of Politics
Authors: Sullivan Vickie B.
Published: April 2018

Catherine Zuckert's Machiavelli's Politics offers an unprecedented interpretation of all of Machiavelli's major works. Her interpretation places Machiavelli in his historical context as he understood it and shows Machiavelli seeking a populist alternative in politics. Because her approach and her conclusion have been championed by scholars explicitly opposed to Strauss's interpretation of Machiavelli, she intervenes in the scholarly debates on Machiavelli by drawing seemingly opposed approaches closer together. Strauss acknowledges the importance of Machiavelli's historical situation and understands him as a type of democrat. Nevertheless, in highlighting the functioning of Machiavelli's republic, Zuckert directly challenges Strauss, who, she argues, focuses too narrowly on Machiavelli's war on Christianity to explicate fully Machiavelli's politics. Religion and politics, though, are inextricably linked in Machiavelli's thought, and his treatment of Christianity's ascendency offers insight into his new republicanism. Consideration of Montesquieu's commentary on Machiavelli underscores some of the excesses of the Florentine's political solutions.
Review Esssay: What Is Human?
Authors: Zuckert Catherine H.
Published: April 2018

John Evans announces the question to which all three of these books respond in his title: What is a human? And in the subtitle, he indicates the reason many people today are concerned about the answers offered to that question: what the different answers mean for human rights. As the debates about the fate of a fetus or comatose patient show, definitions of what is human can determine who lives or dies.
COMPOSITION, STRUCTURE AND BIODIVERSITY OF TREES IN TROPICAL MONTANE CLOUD FOREST PATCHES IN SERRA DO PAPAGAIO STATE PARK, SOUTHEAST BRAZIL
Authors: Ribeiro J. H. C. , Santana L. D. , Carvalho F. A.
Published: April 2018

Tropical montane cloud forests (TMCFs) are characterised principally by frequent immersion in ground-level clouds, which influences their structure. This study aimed to characterise TMCFs in Serra do Papagaio State Park, Minas Gerais State, Southeast Brazil, and to test the hypothesis that TMCF areas can be highly heterogeneous by comparing the tree species composition and structural parameters of 10 TMCF patches in the studied landscape. TMCFs of Serra do Papagaio State Park are of particular interest for conservation, because they contain important populations of threatened tree species.
Potassium iodate levels in processed edible salts available in retail shops throughout Kenya, 2013
Authors: Githinji Gerald Gikonyo , Njine Nancy , Njihia John , Mwihia John , Ransom James
Published: April 2018

Objective

Iodine-deficiency disorders, due to insufficiency of iodine in the diet, are a global public health problem. The Kenyan Food, Drugs and Chemical Substances Act stipulates that processed retail-available edible salts contain 50–84 mg of potassium iodate (KIO3) per kilogram of salt. The present study determined the status of KIO3 levels in commercial salts, for public health action.

Design/Setting/Subjects

As part of the Kenya Demographic and Health Survey 2013, field workers collected salt samples from seven different local manufacturers/packers across eight regions of the country and sent them to the National Public Health Laboratory (NPHL) for KIO3 titration analysis.

Results

A total of 539 samples were collected and analysed at NPHL. The samples had a mean KIO3 of 62 mg/kg. Thirty-three (6 %) samples had KIO3 of <25 mg/kg; ninety-eight (18 %) had 25–49 mg/kg; 335 (62 %) had 50–84 mg/kg; and seventy-three (13 %) had KIO3 of >84 mg/kg.

Conclusions

The study found that 62 % of salts sampled met the Kenyan standards, 24 % were below the required limits and 13 % were above the recommended range. Continuous monitoring of edible salts at the retail level is important to detect brands not adhering to standards and trace them for remedy. However, governmental efforts should be directed to the quality control and quality assurance of the salt-manufacturing industries.
Assessment of the Barren Ground Caribou Die‐off During Winter 2015–2016 Using Passive Microwave Observations
Authors: Dolant C. , Montpetit B. , Langlois A. , Brucker L. , Zolina O. , Johnson C. A. , Royer A. , Smith P.
Published: April 2018

In summer 2016, more than 50 Arctic Barren Ground caribous were found dead on Prince Charles Island (Nunavut, Canada), a species recently classified as threatened. Neither predator nor sign of diseases was observed and reported. The main hypothesis is that caribous were not able to access food due to a very dense snow surface, created by a strong storm system in spring. Using satellite microwave data, a significant increase in brightness temperature polarization ratio at 19 and 37 GHz was observed in spring 2016 (60% higher than previous two winter seasons). Based on microwave radiative transfer simulations, such anomaly can be explained with a very dense snow surface. This is consistent with the succession of storms and strong winds highlighted in ERA‐Interim over Prince Charles Island in spring 2016. Using several sources of data, this study shows that changes in snow conditions explain the caribou die‐off due to restricted foraging.
Mechanical Properties of the Sevier Desert Detachment: An Application of Critical Coulomb Wedge Theory
Authors: Yuan X. P. , Christie‐Blick N. , Braun J.
Published: April 2018

Low‐angle normal faults are widely regarded as playing an important role in crustal extension. Among the most influential examples, the Sevier Desert detachment (SDD) has been imaged in seismic reflection profiles beneath the Sevier Desert basin of west‐central Utah. An extensional offset of as much as 47 km is thought to have occurred since the late Oligocene at or near its present dip of 11°. We use the palinspastic geometry of the preextensional Sevier orogen and critical Coulomb wedge (CCW) theory to constrain the friction coefficient, μD of the inferred detachment. It is assumed that the SDD is at least in part a reactivated strand of the Pavant thrust system. Compressive CCW theory suggests μD values of 0.2–0.24 for thrust faults when crustal shortening ceased in the early Paleocene. A decrease in the dip of the SDD from a maximum of 30° to its present‐day inclination of 11° and extensional CCW theory implies that μD decreased from 0.2–0.24 initially to 0.13 today. Salt, for which the normal‐stress dependence of the friction equation disappears with even shallow burial, is widespread in the Sevier Desert basin and presents locally also in Jurassic strata of central Utah. Elevated pore fluid pressure may have played a role in reducing the effective normal stress. Our model can be tested directly by coring across the detachment and by measuring material properties and the pore fluid pressure in the vicinity of the contact.
A Broadband Laboratory Study of the Seismic Properties of Cracked and Fluid‐Saturated Synthetic Glass Media
Authors: Li Yang , David Emmanuel C. , Nakagawa Seiji , Kneafsey Timothy J. , Schmitt Douglas R. , Jackson Ian
Published: April 2018

For better understanding of frequency dependence (dispersion) of seismic wave velocities caused by stress‐induced fluid flow, broadband laboratory measurements were performed on a suite of synthetic glass media containing both equant pores and thermal cracks. Complementary forced oscillation, resonant bar, and ultrasonic techniques provided access to millihertz‐hertz frequencies, ~1 kHz frequency, and ~1 MHz frequency, respectively. The wave speeds or effective elastic moduli and associated dissipation were measured on samples under dry, argon‐ or nitrogen‐saturated, and water‐saturated conditions in sequence. The elastic moduli, in situ permeability, and crack porosity inferred from in situ X‐ray computed tomography all attest to strong pressure‐induced crack closure for differential (confining‐minus‐pore) pressures <30 MPa, consistent with zero‐pressure crack aspect ratios <4 × 10−4. The low permeabilities of these materials allow access to undrained conditions, even at subhertz frequencies. The ultrasonically measured elastic moduli reveal consistently higher shear and bulk moduli upon fluid saturation—diagnostic of the saturated‐isolated regime. For a glass rod specimen, containing cracks but no pores, saturated‐isolated conditions apparently persist to subhertz frequencies—requiring in situ aspect ratios (minimum/maximum dimension) <10−5. In marked contrast, the shear modulus measured at subhertz frequencies on a cracked glass bead specimen of 5% porosity, is insensitive to fluid saturation, consistent with the Biot‐Gassmann model for the saturated‐isobaric regime. The measured dispersion of the shear modulus approaches 10% over the millihertz‐megahertz frequency range for the cracked and fluid‐saturated media—implying that laboratory ultrasonic data should be used with care in the interpretation of field data.
Upper Crustal Structure and Earthquake Mechanism in the Xinfengjiang Water Reservoir, Guangdong, China
Authors: He Lipeng , Sun Xinlei , Yang Hongfeng , Qin Jialing , Shen Yusong , Ye Xiuwei
Published: April 2018

The Xinfengjiang Water Reservoir (XWR) in Guangdong, China, is one of the reservoirs that have triggered earthquakes of magnitudes greater than 6. Numerous earthquakes have occurred since the impoundment of the reservoir, making it one of the most active seismic zones in Guangdong. However, due to the lack of seismic stations, the detailed seismic structures and earthquake mechanisms within XWR have not been resolved, and the significance of XWR as a typical protracted earthquake location is not well judged. In this study, by collecting waveform data from both permanent and temporary stations from 2012 to 2015, we relocated 1,528 earthquakes and inverted both Vp and Vs structures from traveltimes of these earthquakes. Using waveform data, we also investigated focal mechanisms of earthquakes with magnitude greater than 1.5 in this region. Our results reveal fine crustal structure that has never been shown before and show complicated crust structure with several low‐velocity zones extending to 5–10 km depth under the major faults. Earthquake focal mechanisms show more dip‐slip faults than strike‐slip faults, and the two types of earthquakes are roughly divided by the reservoir boundary. The direction of principle stress of the earthquakes is northwest‐southeast, consistent with the direction of tectonic principal stress. Combining the above results, and investigation of historical earthquakes and water level change, we suggest that water loading cycle and diffusion play important role in XWR seismicity. They increase the pore pressure, make the earthquakes migrate to deeper depth, and change the type of earthquakes.
Energy Dissipation in the Inner Surf Zone: New Insights From LiDAR‐Based Roller Geometry Measurements
Authors: Martins K. , Blenkinsopp C. E. , Deigaard R. , Power H. E.
Published: April 2018

The spatial and temporal variation of energy dissipation rates in breaking waves controls the mean circulation of the surf zone. As this circulation plays an important role in the morphodynamics of beaches, it is vital to develop better understanding of the energy dissipation processes in breaking and broken waves. In this paper, we present the first direct field measurements of roller geometry extracted from a LiDAR data set of broken waves to obtain new insights into wave energy dissipation in the inner surf zone. We use a roller model to show that most existing roller area formulations in the literature lead to considerable overestimation of the wave energy dissipation, which is found to be close to, but smaller than, the energy dissipation in a hydraulic jump of the same height. The role of the roller density is also investigated, and we propose that it should be incorporated into modified roller area formulations until better knowledge of the roller area and its link with the mean roller density is acquired. Finally, using previously published results from deepwater wave breaking studies, we propose a scaling law for energy dissipation in the inner surf zone, which achieves satisfactory results at both the time‐averaged and wave‐by‐wave scales.
Characterizing the Distributed Faulting During the 30 October 2016, Central Italy Earthquake: A Reference for Fault Displacement Hazard Assessment
Authors: Ferrario M. F. , Livio F.
Published: April 2018

Moderate to strong earthquakes (i.e., Mw > ~6.0) commonly produce a complex network of ground ruptures, which are responsible for significant damage. Distributed faulting can affect wide areas (tenths of square kilometers), and expected displacement can be estimated through a probabilistic approach, considering distance from the primary fault and earthquake magnitude. Other factors may have a role in driving the occurrence of distributed faulting; nevertheless, they are not adequately addressed in the current modeling, due to a sensible lack of information. We study the 30 October 2016, Central Italy earthquake (Mw 6.5), to analyze the spatial pattern and geometric characteristics of distributed faulting. We found that distance from the primary structure, fault geometry, and lithology are key factors controlling the distributed faulting occurrence; the local structural setting (i.e., synthetic versus antithetic normal faults systems and relay zones) drives the spatial distribution of faults and the partitioning of the deformation. We also examine other four events occurred in the Italian Apennines since 1980, confirming that traditional models can underestimate the probability of distributed faulting. We suggest that a purely distance‐based probabilistic approach should be integrated using additional parameters derived from earthquake deformation fields or considering the reactivation of preexisting faults.
Characteristics of the Mantle Flow System Beneath the Indochina Peninsula Revealed by Teleseismic Shear Wave Splitting Analysis
Authors: Yu Youqiang , Gao Stephen S. , Liu Kelly H. , Yang Ting , Xue Mei , Le Khanh Phon , Gao Jinyao
Published: April 2018

Numerous geoscientific investigations have been conducted on the southeastern Tibetan Plateau and adjacent areas for understanding crustal and mantle deformation associated with the indentation of the Indian Plate into Eurasia. A number of key issues, such as the causes of a sudden change of fast polarization orientations from N‐S to almost E‐W at approximately 26°N revealed by shear wave splitting (SWS) studies, and the geodynamic implications of the transition still remain enigmatic, partially due to the lack of sufficient SWS measurements on the Indochina Peninsula. Here we employ the SWS technique to systematically illuminate upper mantle anisotropy beneath the Indochina Peninsula with an unprecedented data coverage. The resulting 409 SWS measurements from 29 stations show that upper mantle anisotropy beneath the vast majority of the study area is characterized by dominantly E‐W fast orientations which are nearly orthogonal to the strike of most of the major tectonic features in the study area, ruling out significant lithospheric contributions to the observed anisotropy. This observation, when combined with results from seismic tomography, numerical modeling, surface movement, and focal mechanism investigations, suggests that the observed azimuthal anisotropy is mostly the consequence of absolute plate motion or the westward rollback of the oceanic Indian slab. The flow system induced by the rollback or absolute plate motion may experience regional alteration from mantle upwelling along the eastern edge of the slab and through a previously detected slab window, leading to local variations in the observed splitting parameters.
Deconvolving the Fate of Carbon in Coastal Sediments
Authors: Van der Voort Tessa S. , Mannu Utsav , Blattmann Thomas M. , Bao Rui , Zhao Meixun , Eglinton Timothy I.
Published: April 2018

Coastal oceans play a crucial role in the global carbon cycle, and are increasingly affected by anthropogenic forcing. Understanding carbon cycling in coastal environments is hindered by convoluted sources and myriad processes that vary over a range of spatial and temporal scales. In this study, we deconvolve the complex mosaic of organic carbon manifested in Chinese Marginal Sea (CMS) sediments using a novel numerical clustering algorithm based on 14C and total OC content. Results reveal five regions that encompass geographically distinct depositional settings. Complementary statistical analyses reveal contrasting region‐dependent controls on carbon dynamics and composition. Overall, clustering is shown to be highly effective in demarcating areas of distinct organic facies by disentangling intertwined organic geochemical patterns resulting from superimposed effects of OC provenance, reworking and deposition on a shelf region exhibiting pronounced spatial heterogeneity. This information will aid in constraining region‐specific budgets of carbon burial and carbon cycle processes.
Coupling of the Quasi‐Biweekly Oscillation of the Tibetan Plateau Summer Monsoon With the Arctic Oscillation
Authors: Wang Meirong , Wang Jun , Duan Anmin , Liu Yimin , Zhou Shunwu
Published: April 2018

The intraseasonal variation of the Tibetan Plateau summer monsoon (TPSM) during 1979–2011 is investigated. The TPSM shows a dominant quasi‐biweekly oscillation (QBWO) in most summer seasons, and its active/break phases are closely related to more/less precipitation over the Tibetan Plateau. We suggest that the TPSM QBWO is associated with a southeastward propagating nonstationary wave train in the middle and upper troposphere. It shows equivalent barotropic vertical structures over the midlatitudes and a baroclinic structure over the eastern Tibetan Plateau. Wave activity flux analysis indicates that it originates from northern Europe, which is an active center of the summertime Arctic Oscillation (AO). The AO also shows significant QBWO signals and leads TPSM QBWO by about 13 days. Phase composite and wave activity flux analyses of AO QBWO confirmed that the wave train influences TPSM QBWO, suggesting that AO plays an important role in the TPSM on a 10‐ to 20‐day timescale.
A Novel Channel‐Synthesizing Method for Reducing Uncertainties in Satellite Radiative Transfer Modeling
Authors: Lu Yinghui , Zhang Fuqing
Published: April 2018

Most sounding channels sensitive to atmosphere layers close to Earth's surface are also sensitive to Earth's surface properties. Biases and uncertainties in Earth's surface emissivity and skin temperature may degrade the values of these observations being assimilated into weather prediction models. A method that combines several individual channels into a synthesized channel is proposed here to reduce such uncertainties. The effectiveness of such channel‐synthesizing method is first demonstrated through perfect model experiments, where brightness temperatures are simulated and compared before and after noises added to surface emissivity and skin temperature. Real‐case experiments that compare simulated brightness temperature and satellite observations further show that the synthesized channel can effectively reduce the mean bias of simulated brightness temperature from 1 to 3 K for individual GOES‐R channels to near zero for the synthesized channel, suggesting great potential of the approach for more effective assimilation of surface‐sensitive sounding channels.
Topside Ionospheric Electron Temperature Observations of the 21 August 2017 Eclipse by DMSP Spacecraft
Authors: Hairston Marc R. , Mrak Sebastijan , Coley W. R. , Burrell Angeline , Holt Ben , Perdue Michael , Depew Matthew , Power Robert
Published: April 2018

During the 21 August 2017 eclipse two separate DMSP spacecraft passed through the lunar penumbra at local afternoon (F16) and near local sunset (F17) in the topside ionosphere at an altitude of ~850 km. Measurements of the in situ electron temperature by the Langmuir probe on each spacecraft showed regions where the temperature decreased on the order of 500 to 1,000 K in the shadow. The patterns of these decreases were sporadic inside the shadow but generally showed the same overall shape in both passes. Comparing these patterns of temperature reductions with the projection of the gradient of the solar EUV radiation in the ionosphere suggests that these complex patterns are a result of the nonuniform distribution of the solar EUV radiation on the Sun at the time of the eclipse.
A Revisit of Global Dimming and Brightening Based on the Sunshine Duration
Authors: He Yanyi , Wang Kaicun , Zhou Chunlüe , Wild Martin
Published: April 2018

Observations show that the surface incident solar radiation (Rs) decreased over land from the 1950s to the 1980s and increased thereafter, known as global dimming and brightening. This claim has been questioned due to the inhomogeneity and low spatial‐temporal coverage of Rs observations. Based on direct comparisons of ~200 observed and sunshine duration (SunDu) derived Rs station pairs, meeting data record lengths exceeding 60 months and spatial distances less than 110 km, we show that meteorological observations of SunDu can be used as a proxy for measured Rs. Our revised results from ~2,600 stations show global dimming from the 1950s to the 1980s over China (−1.90 W/m2 per decade), Europe (−1.36 W/m2 per decade), and the United States (−1.10 W/m2 per decade), brightening from 1980 to 2009 in Europe (1.66 W/m2 per decade) and a decline from 1994 to 2010 in China (−1.06 W/m2 per decade). Even if 1994–2010 is well known as a period of global brightening, the observed and SunDu‐derived Rs over China still exhibit declining trends. Trends in Rs from 1923 to 1950 are also found over Europe (1.91 W/m2 per decade) and the United States (−1.31 W/m2 per decade), but the results in Europe may not well represent the actual trend for the European continent due to poor spatial sampling.
Predicting the Dominant Patterns of Subseasonal Variability of Wintertime Surface Air Temperature in Extratropical Northern Hemisphere
Authors: Lin Hai
Published: April 2018

Skillfully predicting persistent extreme temperature anomalies more than 10 days in advance remains a challenge although it is of great value to the society. Here the two leading modes of subseasonal variability of surface air temperature over the extratropical Northern Hemisphere in boreal winter are identified with pentad (5 days) averaged data. They are well separated geographically, dominating temperature variability in North America and Eurasia, respectively. There exists a two‐pentad lagged correlation between these two modes, implying an intercontinental link of temperature variability. Forecast skill of these two modes is evaluated based on three operational subseasonal prediction models. The results show that useful forecasts of the Eurasian mode (EOF2) can be achieved four pentads in advance, which is more skillful than the North American mode (EOF1). EOF2 is found to benefit from the Madden‐Julian Oscillation signal in the initial condition.
Dependence of Lunar Tide of the Equatorial Electrojet on the Wintertime Polar Vortex, Solar Flux, and QBO
Authors: Siddiqui T. A. , Yamazaki Y. , Stolle C. , Lühr H. , Matzka J. , Maute A. , Pedatella N.
Published: April 2018

The lower atmospheric forcing effects on the ionosphere are particularly evident during extreme meteorological events known as sudden stratospheric warmings (SSWs). During SSWs, the polar stratosphere and ionosphere, two distant atmospheric regions, are coupled through the SSW‐induced modulation of atmospheric migrating and nonmigrating tides. The changes in the migrating semidiurnal solar and lunar tides are the major source of ionospheric variabilities during SSWs. In this study, we use 55 years of ground‐magnetometer observations to investigate the composite characteristics of the lunar tide of the equatorial electrojet (EEJ) during SSWs. These long‐term observations allow us to capture the EEJ lunar tidal response to the SSWs in a statistical sense. Further, we examine the influence of solar flux conditions and the phases of quasi‐biennial oscillation (QBO) on the lunar tide and find that the QBO phases and solar flux conditions modulate the EEJ lunar tidal response during SSWs in a similar way as they modulate the wintertime Arctic polar vortex. This work provides first evidence of modulation of the EEJ lunar tide due to QBO.
A New Approach to Improve the Track Prediction of Tropical Cyclones Over North Indian Ocean
Authors: Saranya Ganesh S. , Sahai A. K. , Abhilash S. , Joseph S. , Dey A. , Mandal R. , Chattopadhyay R. , Phani R.
Published: April 2018

The implementation of a bias‐correction and signal amplification technique to the National Center for Environmental Prediction's Climate Forecast System‐based Grand Ensemble Prediction System Multi‐Model Ensemble outputs is studied for improvements in track predictions of three cyclonic storms over North Indian Ocean. Bias‐correction method involves the removal of lead‐dependent climatological bias from multi‐model ensemble forecasts by using European Centre for Medium‐Range Weather Forecasts Re‐analysis (ERA‐Interim) daily‐averaged data sets as observations. The corrected data are then subjected to signal amplification procedure involving a two‐point space and time correction of ensembles based on the leading signal (ensemble mean), whereby large uncertainties and disagreements between different model outputs are reduced. Results show that bias‐correction and signal amplification technique is, indeed, improving the track forecasts of selected cyclonic storm cases with significant reduction in track errors even at longer lead times.
Global Validation of MODIS Near‐Surface Air and Dew Point Temperatures
Authors: Famiglietti Caroline A. , Fisher Joshua B. , Halverson Gregory , Borbas Eva E.
Published: April 2018

This analysis is the first global validation of the Moderate Resolution Imaging Spectroradiometer (MODIS)‐derived near‐surface air temperature and dew point estimates, which both serve as crucial input data in models of energy, water, and carbon exchange between terrestrial ecosystems and the atmosphere. By hypsometrically interpolating the MOD07 Level‐2 atmospheric profile product to surface pressure level, we obtained near‐surface air temperature and dew point observations at 5 km pixel resolution. We compared these daily data, retrieved over a 14‐year record, to corresponding measurements from 109 ground meteorological stations (FLUXNET). Our results show strong agreement between satellite and in situ near‐surface air temperature measurements (R2 = 0.89, root‐mean‐square error = 3.47°C, and bias = −0.19°C) and dew point observations (R2 = 0.76, root‐mean‐square error = 5.04°C, and bias = 0.79°C) with insignificant differences in error across climate zones. This validation is among the earliest assessments of the reprocessed, crosstalk‐corrected Collection 6.1 Terra MODIS data and provides support for widespread applications of near‐surface atmospheric data.
Nonlinear Response of the Stratosphere and the North Atlantic‐European Climate to Global Warming
Authors: Manzini E. , Karpechko A. Yu. , Kornblueh L.
Published: April 2018

The response of the northern winter atmospheric circulation for two consecutive global warming periods of 2 K is examined in a grand ensemble (68 members) of idealized CO2 increase experiments performed with the same climate model. The comparison of the atmospheric responses for the two periods shows remarkable differences, indicating the nonlinearity of the response. The nonlinear signature of the atmospheric and surface responses is reminiscent of the positive phase of the annular mode of variability. The stratospheric vortex response shifts from an easterly wind change for the first 2 K to a westerly wind change for the second 2 K. The North Atlantic storm track shifts poleward only in the second period. A weaker November Arctic amplification during the second period suggests that differences in Arctic sea ice changes can act to trigger the atmospheric nonlinear response. Stratosphere‐troposphere coupling thereafter can provide for the persistence of this nonlinearity throughout the winter.
Magnetic Activity Dependence of the Electric Drift Below L = 3
Authors: Lejosne Solène , Mozer F. S.
Published: April 2018

More than 2 years of magnetic and electric field measurements by the Van Allen Probes are analyzed with the objective of determining the average effects of magnetic activity on the electric drift below L = 3. The study finds that an increase in magnetospheric convection leads to a decrease in the magnitude of the azimuthal component of the electric drift, especially in the nightside. The amplitude of the slowdown is a function of L, magnetic local time, and Kp, in a pattern consistent with the storm time dynamics of the ionosphere and thermosphere. To a lesser extent, magnetic activity also alters the average radial component of the electric drift below L = 3. A global picture for the average variations of the electric drift with Kp is provided as a function of L and magnetic local time. It is the first time that the signature of the ionospheric disturbance dynamo is observed in near‐equatorial electric drift measurements.
The MJO‐SSW Teleconnection: Interaction Between MJO‐Forced Waves and the Midlatitude Jet
Authors: Kang Wanying , Tziperman Eli
Published: April 2018

The Madden‐Julian Oscillation (MJO) was shown to affect both present‐day sudden stratospheric warming (SSW) events in the Arctic and their future frequency under global warming scenarios, with implications to the Arctic Oscillation and midlatitude extreme weather. This work uses a dry dynamic core model to understand the dependence of SSW frequency on the amplitude and longitudinal range of the MJO, motivated by the prediction that the MJO will strengthen and broaden its longitudinal range in a warmer climate. We focus on the response of the midlatitude jets and the corresponding generated stationary waves, which are shown to dominate the response of SSW events to MJO forcing. Momentum budget analysis of a large ensemble of spinup simulations suggests that the climatological jet response is driven by the MJO‐forced meridional eddy momentum transport. The results suggest that the trends in both MJO amplitude and longitudinal range are important for the prediction of the midlatitude jet response and for the prediction of SSWs in a future climate.
Arctic Sea Ice Drift Measured by Shipboard Marine Radar
Authors: Lund B. , Graber H. C. , Persson P. O. G. , Smith M. , Doble M. , Thomson J. , Wadhams P.
Published: April 2018

This study presents Arctic sea ice drift fields measured by shipboard marine X‐band radar (MR). The measurements are based on the maximum cross correlation between two sequential MR backscatter images separated ∼1 min in time, a method that is commonly used to estimate sea ice drift from satellite products. The advantage of MR is that images in close temporal proximity are readily available. A typical MR antenna rotation period is ∼1–2 s, whereas satellite revisit times can be on the order of days. The technique is applied to ∼4 weeks of measurements taken from R/V Sikuliaq in the Beaufort Sea in the fall of 2015. The resulting sea ice velocity fields have ∼500 m and up to ∼5 min resolution, covering a maximum range of ∼4 km. The MR velocity fields are validated using the GPS‐tracked motion of Surface Wave Instrument Float with Tracking (SWIFT) drifters, wave buoys, and R/V Sikuliaq during ice stations. The comparison between MR and reference sea ice drift measurements yields root‐mean‐square errors from 0.8 to 5.6 cm s−1. The MR sea ice velocity fields near the ice edge reveal strong horizontal gradients and peak speeds > 1 m s−1. The observed submesoscale sea ice drift processes include an eddy with ∼6 km diameter and vorticities <–2 (normalized by the Coriolis frequency) as well as converging and diverging flow with normalized divergences <–2 and >1, respectively. The sea ice drift speed correlates only weakly with the wind speed (r2 = 0.34), which presents a challenge to conventional wisdom.
Modeling of Nonlocal Thermodynamic Equilibrium Effects in the Classical and Principal Component‐Based Version of the RTTOV Fast Radiative Transfer Model
Authors: Matricardi Marco , López‐Puertas Manuel , Funke Bernd
Published: April 2018

The direct assimilation in 4D‐Var of principal component (PC) scores derived from Infrared Atmospheric Sounding Interferometer (IASI) spectra has recently been demonstrated. To maximize the exploitation of the IASI instrument, a future step is to consider the extension of the PC approach to the extraction of information from the 4.3‐μm CO2‐absorbing region. Shortwave IASI channels are currently underused compared to similar longwave channels because of day‐night variations in data usability due to departures from local thermodynamic equilibrium (LTE). In this paper, we document the introduction of non‐LTE (NLTE) effects in the PC‐based version of the radiative transfer for TIROS operational vertical sounder (RTTOV) fast radiative transfer model (PC‐RTTOV). The inclusion of NLTE effects in PC‐RTTOV has required the development of a parameterized scheme that allows the fast computation of a NLTE correction to LTE radiances. The fast NLTE model is general enough to be applied to any sensor and can be utilized to add a fast and accurate NLTE correction to polychromatic LTE spectra computed by any general radiative transfer model, including RTTOV, which now incorporates the fast NLTE model developed in this study. The accuracy of the NLTE correction is such that daytime and nighttime radiances can be simulated to almost the same degree of accuracy. The comparison with IASI observations shows that the fast NLTE model presented here performs significantly better than the fast NLTE model incorporated in the previous version of RTTOV and also that improvements have to be made to the simulation of NLTE effects at winter high latitudes.
Radiative‐Transfer Modeling of Spectra of Planetary Regoliths Using Cluster‐Based Dense Packing Modifications
Authors: Ito Gen , Mishchenko Michael I. , Glotch Timothy D.
Published: April 2018

In remote sensing of planetary bodies, the development of analysis techniques that lead to quantitative interpretations of data sets has relatively been deficient compared to the wealth of acquired data, especially in the case of regoliths with particle sizes on the order of the probing wavelength. Radiative transfer theory has often been applied to the study of densely packed particulate media like planetary regoliths, but with difficulty; here we continue to improve theoretical modeling of spectra of densely packed particulate media. We use the superposition T‐matrix method to compute the scattering properties of an elementary volume entering the radiative transfer equation by modeling it as a cluster of particles and thereby capture the near‐field effects important for dense packing. Then, these scattering parameters are modified with the static structure factor correction to suppress the irrelevant far‐field diffraction peak rendered by the T‐matrix procedure. Using the corrected single‐scattering parameters, reflectance (and emissivity) is computed via the invariant‐imbedding solution to the scalar radiative transfer equation. We modeled the emissivity spectrum of the 3.3 μm particle size fraction of enstatite, representing a common regolith component, in the midinfrared (~5–50 μm). The use of the static structure factor correction coupled with the superposition T‐matrix method produced better agreement with the corresponding laboratory spectrum than the sole use of the T‐matrix method, particularly for volume scattering wavelengths (transparency features). This work demonstrates the importance of proper treatment of the packing effects when modeling semi‐infinite densely packed particulate media using finite, cluster‐based light scattering models.
Long noncoding RNA TUG1 facilitates osteogenic differentiation of periodontal ligament stem cells via interacting with Lin28A
Authors: He Qin , Yang Shuangyan , Gu Xiuge , Li Mengying , Wang Chunling , Wei Fulan
Published: April 2018

Periodontal ligament stem cells (PDLSCs) are mesenchymal stem cells derived from dental tissues with multidirectional differentiation potential and excellent self-renewing ability. Recently, long noncoding RNAs (lncRNAs) have been shown to play important roles in MSC osteogenic differentiation. In this study, we found that taurine upregulated gene 1 (TUG1), an evolutionarily conserved and widely present lncRNA was significantly upregulated in osteogenically induced PDLSCs compared to their undifferentiated counterparts. Further investigation demonstrated that the expression of TUG1 was positively correlated with the osteogenic differentiation of PDLSCs following the induction, as evidenced by the increase in cellular alkaline phosphatase (ALP) level, formation of calcium nodules, and the upregulation of several osteogenic-related gene markers such as ALP, osteocalcin (OCN), and runt-related transcription factor 2 (Runx2). Conversely, TUG1 knockdown was demonstrated to inhibit the potential of PDLSCs for osteogenic differentiation. Using bioinformatics analysis, we identified lin-28 homolog A (Lin28A) as a potential target of TUG1 during osteogenic differentiation of PDLSCs. Lin28A was found to be significantly downregulated in TUG1-repressed PDLSCs and contained multiple binding sites for lncRNA TUG1. Moreover, suppression of Lin28A was shown to be able to inhibit osteogenic differentiation and decreased the expression of several osteogenic genes. Taken together, these results could help researchers better understand the mechanism that governs the osteogenic differentiation of PDLSCs, and also serve as a stepping stone for the development of novel therapeutic strategies that can be used to regenerate dental tissues.
A SUMO-dependent feedback loop senses and controls the biogenesis of nuclear pore subunits
Authors: Rouvière Jérôme O. , Bulfoni Manuel , Tuck Alex , Cosson Bertrand , Devaux Frédéric , Palancade Benoit
Published: April 2018

While the activity of multiprotein complexes is crucial for cellular metabolism, little is known about the mechanisms that collectively control the expression of their components. Here, we investigate the regulations targeting the biogenesis of the nuclear pore complex (NPC), the macromolecular assembly mediating nucleocytoplasmic exchanges. Systematic analysis of RNA-binding proteins interactomes, together with in vivo and in vitro assays, reveal that a subset ofNPCmRNAs are specifically bound by Hek2, a yeast hnRNP K-like protein. Hek2-dependent translational repression and protein turnover are further shown to finely tune the levels of NPC subunits. Strikingly, mutations or physiological perturbations altering pore integrity decrease the levels of the NPC-associated SUMO protease Ulp1, and trigger the accumulation of sumoylated versions of Hek2 unable to bindNPCmRNAs. Our results support the existence of a quality control mechanism involving Ulp1 as a sensor of NPC integrity and Hek2 as a repressor of NPC biogenesis.