bluuebunny/crossref_metadata_2025 huggingface dataset:
Raising the flag among the ruins: the crisis as helping hand for opposition parties?
Authors: Conti Nicolò , Pedrazzani Andrea , Russo Federico
Published: April 2019

Within the context of the economic downturn in southern Eurozone countries and the imposition of new constraints on national policy-making, this article examines the congruence between party issue prioritization, during and after the electoral phase. This is done through a longitudinal analysis of four countries (Greece, Italy, Portugal, and Spain) and use of party manifesto and parliamentary question data. We found that between the electoral and parliamentary arenas, parties tend to emphasize different issues. However, this occurs in different ways across time, countries, and parties. We propose a measurement of issue congruence in agenda framing between the pre- and post-electoral phases to assess to what extent elections provide a guide for public policies. Moreover, we propose arguments to explain different results in the analyzed countries and across parties. We show that the crisis magnified the capacity of the opposition to maintain programmatic coherence – a helping hand for opposition parties (including the radical ones) that succeeded in boosting the relevance of their signature issues.
Estimating lift from wake velocity data in flapping flight
Authors: Wang Shizhao , He Guowei , Liu Tianshu
Published: April 2019

The application of the Kutta–Joukowski (KJ) theorem to estimating the lift of a flying animal based on wake velocity fields often leads to significant underprediction of the lift, which is known as the wake momentum paradox. This work attempts to answer the puzzling question on whether the KJ theorem is legitimate in its use for complex viscous unsteady wakes generated by flapping wings. The limitations in applying the KJ theorem to flapping wings are quantitatively examined through numerical simulations of viscous incompressible flows over three flapping wing models. The three flapping wing models studied in this work are a flapping wing with a fixed wingspan, a flapping wing with a dynamically changing wingspan and a dihedral flapping wing. The KJ theorem fails to give a satisfactory prediction of the time-averaged lift unless an effective span length is correctly computed. We propose a wake-sectional Kutta–Joukowski (WS-KJ) model to predict the time-averaged lift, where the effective span length is computed based on the time-averaged distance between the streamwise vorticity centroids in the right and left half sides of the Trefftz plane. The WS-KJ model incorporates the spatial evolutionary effects of the complex vortex structures in the wake and significantly improves the prediction of the time-averaged lift. The physical foundation for such improvement is explored. In addition, the time-dependent amplitude and phase changes of the unsteady lift are discussed as the fluid acceleration effect.
Two mechanisms of modulation of very-large-scale motions by inertial particles in open channel flow
Authors: Wang G. , Richter D. H.
Published: April 2019

Very-large-scale motions (VLSMs) and large-scale motions (LSMs) coexist at moderate Reynolds numbers in a very long open channel flow. Direct numerical simulations two-way coupled with inertial particles are analysed using spectral information to investigate the modulation of VLSMs. In the wall-normal direction, particle distributions (mean/preferential concentration) exhibit two distinct behaviours in the inner flow and outer flow, corresponding to two highly anisotropic turbulent structures, LSMs and VLSMs. This results in particle inertia’s non-monotonic effects on the VLSMs: low inertia (based on the inner scale) and high inertia (based on the outer scale) both strengthen the VLSMs, whereas moderate and very high inertia have little influence. Through conditional tests, low- and high-inertia particles enhance VLSMs following two distinct routes. Low-inertia particles promote VLSMs indirectly through the enhancement of the regeneration cycle (the self-sustaining mechanism of LSMs) in the inner region, whereas high-inertia particles enhance the VLSM directly through contribution to the Reynolds shear stress at similar temporal scales in the outer region. This understanding also provides more general insight into inner–outer interaction in high-Reynolds-number, wall-bounded flows.
The Half-Life of 14C—Why Is It So Long?
Authors: Kutschera Walter
Published: April 2019

The half-life of radiocarbon (14C) is 5700 ± 30 yr, which makes it particularly useful for dating in archaeology. However, only an exceptional hindrance of the beta decay from 14C to 14N—a so-called Gamow-Teller ß-decay—makes this half-life so long. A normal strength would result in a half-life of only a few days, completely useless for archaeological dating. The unusual hindrance is based on the nuclear structure of the two nuclei, resulting in strongly destructive interferences of the nuclear transition matrix element. Nuclear model calculation with great computational efforts have been performed in the literature to reproduce the very low transition probability. Here, we will attempt to describe the nuclear physics behind this most unusual half-life.
UV Photochemical Oxidation and Extraction of Marine Dissolved Organic Carbon at UC Irvine: Status, Surprises, and Methodological Recommendations
Authors: Walker Brett D , Beaupré Steven R , Griffin Sheila , Druffel Ellen R M
Published: April 2019

The first ultraviolet photochemical oxidation (UVox) extraction method for marine dissolved organic carbon (DOC) as CO2 gas was established by Armstrong and co-workers in 1966. Subsequent refinement of the UVox technique has co-evolved with the need for high-precision isotopic (Δ14C, δ13C) analysis and smaller sample size requirements for accelerator mass spectrometry radiocarbon (AMS 14C) measurements. The UVox line at UC Irvine was established in 2004 and the system reaction kinetics and efficiency for isolating seawater DOC rigorously tested for quantitative isolation of ∼1 mg C for AMS 14C measurements. Since then, improvements have been made to sampling, storage, and UVox methods to increase overall efficiency. We discuss our progress, and key UVox system parameters for optimizing precision, accuracy, and efficiency, including (1) ocean to reactor: filtration, storage and preparation of DOC samples, (2) cryogenic trap design, efficiency and quantification of CO2 break through, and (3) use of isotopic standards, blanks and small sample graphitization techniques for the correction of DOC concentrations and Fm values with propagated uncertainties. New DOC UVox systems are in use at many institutions. However, rigorous assessment of quantitative UVox DOC yields and blank contributions, DOC concentrations and carbon isotopic values need to be made. We highlight the need for a community-wide inter-comparison study.
Can smartphone vibration provide a valid alternative to tuning forks for use on the ENT ward round?
Authors: Hopkins M E , Owens D
Published: April 2019

Background

All patients undergoing tympanomastoid surgery should be assessed post-operatively for a ‘dead ear’; however, tuning forks are frequently inaccessible.

Objective

To demonstrate that smartphone-based vibration applications provide equivalent accuracy to tuning forks when performing Weber's test.

Methods

Data were collected on lay participants with no underlying hearing loss. Earplugs were used to simulate conductive hearing loss. Both the right and left ears were tested with the iBrateMe vibration application on an iPhone and using a 512 Hz tuning fork.

Results

Occluding the left ear, the tuning fork lateralised to the left in 18 out of 20 cases. In 20 out of 20 cases, sound lateralised to the left with the iPhone (chi-square test, p = 0.147). Occluding the right ear, the tuning fork lateralised to the right in 19 out of 20 cases. In 19 out of 20 cases, sound lateralised to the right with the iPhone (chi-square test, p > 0.999).

Conclusion

Smartphone-based vibration applications represent a viable, more accessible alternative to tuning forks when assessing for conductive hearing loss. They can therefore be utilised on the ward round, in patients following tympanomastoid surgery, for example.
A Sliding Mode Force and Position Controller Synthesis for Series Elastic Actuators
Authors: Sariyildiz Emre , Mutlu Rahim , Yu Haoyong
Published: April 2019

This paper deals with the robust force and position control problems of series elastic actuators (SEAs). It is shown that an SEA’s force control problem can be described by a second-order dynamic model which suffers from only matched disturbances. However, the position control dynamics of an SEA is of fourth order and includes matched and mismatched disturbances. In other words, an SEA’s position control is more complicated than its force control, particularly when disturbances are considered. A novel robust motion controller is proposed for SEAs by using disturbance observer (DOb) and sliding mode control. When the proposed robust motion controller is implemented, an SEA can precisely track desired trajectories and safely contact with an unknown and dynamic environment. The proposed motion controller does not require precise dynamic models of environments and SEAs. Therefore, it can be applied to many different advanced robotic systems such as compliant humanoids, industrial robots and exoskeletons. The validity of the proposed motion controller is experimentally verified.
A practical guide to pharmaceutical analyses using X-ray powder diffraction
Authors: Fawcett T. G. , Gates-Rector S. , Gindhart A. M. , Rost M. , Kabekkodu S. N. , Blanton J. R. , Blanton T. N.
Published: April 2019

Advances in instrumentation, software applications, and database content have all contributed to improvements in pharmaceutical analyses by powder diffraction methods in the 21stcentury. When compared to the globally harmonized United States Pharmacopeia General Chapter <941>, “Characterization of Crystalline and Partially Crystalline Solids by X-ray Powder Diffraction”, many historic problems in pharmaceutical analysis have been addressed by combinations of improved methods and instrumentation. Major changes in the last 20 years include (i) a dramatic lowering in detection capability and detection limits, (ii) enhanced capabilities for dynamic measurements such asin situanalyses under a variety of conditions, and (iii) the ability to identify and characterize nanomaterials, non-crystalline, and amorphous materials by both coherent and incoherent scattering profiles.
The interplay of polygenic plasticity and adrenocortical activity as sources of variability in pathways among family adversity, youth emotional reactivity, and psychological problems
Authors: Davies Patrick T. , Cicchetti Dante , Thompson Morgan J. , Bascoe Sonnette M. , Cummings E. Mark
Published: April 2019

This study examined the interplay between a polygenic composite and cortisol activity as moderators of the mediational pathway among family adversity, youth negative emotional reactivity to family conflict, and their psychological problems. The longitudinal design contained three annual measurement occasions with 279 adolescents (Mean age = 13.0 years) and their parents. Latent difference score analyses indicated that observational ratings of adversity in interparental and parent–child interactions at Wave 1 predicted increases in a multimethod, multi-informant assessment of youth negative emotional reactivity to family conflict from Waves 1 to 2. Changes in youth negative emotional reactivity, in turn, predicted increases in a multi-informant (i.e., parents, adolescent, and teacher) assessment of psychological problems from Waves 1 to 3. Consistent with differential susceptibility theory, the association between family adversity and negative emotional reactivity was stronger for adolescents who carried more sensitivity alleles in a polygenic composite consisting of 5-HTTLPR, DRD4 VNTR, and BDNF polymorphisms. Analyses of adolescent cortisol in the period surrounding a family disagreement task at Wave 1 revealed that overall cortisol output, rather than cortisol reactivity, served as an endophenotype of the polygenic composite. Overall cortisol output was specifically associated with polygenic plasticity and moderated the association between family adversity and youth negative emotional reactivity in the same for better or for worse manner as the genetic composite. Finally, moderator-mediated-moderation analyses indicated that the moderating role of the polygenic plasticity composite was mediated by the moderating role of adolescent cortisol output in the association between family adversity and their emotional reactivity.
Judging clinical competence using structured observation tools: A cautionary tale
Authors: Roth Anthony D. , Myles-Hooton Pamela , Branson Amanda
Published: April 2019

Background:

One method for appraising the competence with which psychological therapy is delivered is to use a structured assessment tool that rates audio or video recordings of therapist performance against a standard set of criteria.

Aims:

The present study examines the inter-rater reliability of a well-established instrument (the Cognitive Therapy Scale – Revised) and a newly developed scale for assessing competence in CBT.

Method:

Six experienced raters working independently and blind to each other’s ratings rated 25 video recordings of therapy being undertaken by CBT therapists in training.

Results:

Inter-rater reliability was found to be low on both instruments.

Conclusions:

It is argued that the results represent a realistic appraisal of the accuracy of rating scales, and that the figures often cited for inter-rater reliability are unlikely to be generalizable outside the specific context in which they were achieved. The findings raise concerns about the use of these scales for making summative judgements of clinical competence in both educational and research contexts.
Associations among serum folate, waist-to-hip ratio, lipid profile, and eating habits with homocysteine in an elderly Thai population
Authors: Paratthakonkun Chirawat , Kaewprasert Sarunya , Arthan Dumrongkiet , Soonthornworasiri Ngamphol , Tungtrongchitr Rungsunn , Prangthip Pattaneeya , Wongsutthilerd Alisara , Pooudoung Somchai , Chantaranipapong Yaovamarn , Nakosiri Wanyarat , Aroonnual Amornrat , Chupeerach Chaowanee , Chanchai Siriporn , Nana Arth
Published: April 2019

Abstract. A lower serum folate level is common in older populations and is associated with increased serum homocysteine concentration. In turn, an elevated homocysteine level is associated with increased risk of cardiovascular disease and age-related diseases. Contemporary studies of folate and dietary risk factors for cardiovascular disease among the elderly population in Thailand are lacking. This cross-sectional study aimed to investigate the relationships among serum folate, homocysteine level, and nutritional status in the elderly Thai. Three hundred individuals, aged 60 years and over, underwent anthropometric and physiological measurements, and biochemical parameters, and eating habits were also determined. Folate insufficiency was found in approximately 35% of subjects. Folate and homocysteine showed a significant inverse correlation. Serum homocysteine levels rose with increasing age. Folate deficiency and high waist-to-hip ratio were associated with 7-fold and 2.5-fold increased risk for hyperhomocysteinemia, respectively. There were positive correlations between homocysteine and waist-to-hip ratio and systolic blood pressure, but a negative correlation between homocysteine and high-density lipoprotein ( r = −0.239, p < 0.01), which are markers for cardiovascular disease risk. Folate negatively correlated with body mass index, waist-to-hip ratio, and diastolic blood pressure, but positively with high-density lipoprotein ( r = 0.162, p < 0.01). Investigation of eating habits showed that low consumption of green leafy vegetables and high consumption of sugary foods were associated with high homocysteine levels. Given associations between nutritional status and cardiovascular disease confirmed in this study, nutrition education, holistic health promotion, and appropriate behavioral modification of eating habits represent important measures for preventing premature cardiovascular disease in the elderly Thai population.
Duplicate portion sampling gives the most accurate iron intake estimate: Implications for iron status of female students
Authors: Ghaseminasab Parizi Maryam , Tangestani Hadith , Rahmdel Samane , Aqaeinejad R. Seyed Mohammad , Abdollahzadeh Seyedeh Maryam , Mazloomi Seyed Mohammad
Published: April 2019

Abstract. Iron deficiency (ID) is one of the most common nutritional problems in the developing world, affecting primarily women of childbearing age. Poor dietary iron intake is a major reason of ID. Accurate measurement of iron intake is of crucial importance to combat the problem. The daily dietary iron intake of 67 female students aged between 20-30 years (a mean BMI of 21.8±3.4 kg/m2) was evaluated using three assessment methods: atomic absorption spectrometry of 3-day food duplicate samples, and food composition tables (FCTs) in combination with either food frequency questionnaire (FFQ) or dietary records. Iron status was examined using hematological and biochemical tests. The dietary iron intake determined by duplicate portion sampling (DPS; 4.12±1.84 mg/day) was significantly lower than the FCT-based estimates ( P<0.001), and it was less than ¼ of the recommended dietary allowance of 18 mg/day. No significant correlation was found between DPS technique and FCT-based assessment methods. Fifty percent of the participants had small or depleted iron stores (serum ferritin< 30 ng/mL), but only 4.5% had ID anemia (serum ferritin< 12 ng/mL and hemoglobin<12 g/dL). Dietary iron intakes and FFQ-based intakes of vitamin C were not significantly correlated with all the investigated hematological parameters. In order to take some steps toward more practical approaches to combat this health problem, development of an accurate iron intake assessment seems to be the first priority. In this regard, improvement and validation of national FCTs would be a promising solution.
Intermittency in Solar Wind Turbulence From Fluid to Kinetic Scales
Authors: Bruno Roberto
Published: April 2019

Solar wind is a highly turbulent medium exhibiting fluctuations ranging from the solar sidereal rotation period to proton and electron gyroperiods. Their amplitudes show remarkable scalings with frequency across more than seven decades, suggesting a self‐similar nature for these fluctuations. However, these fluctuations are not globally scale invariant and require a multifractal approach. Multifractality is closely related to intermittency, a phenomenon that has been studied in the solar wind for more than three decades. We now have a rather complete picture of the nature of the most intermittent events and the radial/latitudinal dependence of this phenomenon in the heliosphere. Parallel shocks, slow mode shocks or tangential discontinuities/current sheets identified as the border between adjacent flux tubes are the most intermittent structures within the low‐frequency turbulence. It is more complicated and fascinating to understand the nature of intermittent events at kinetic scales since they are directly related to dissipative phenomena and might be the key to understanding the dissipation mechanisms in the collisionless solar wind plasma. Unfortunately, we still do not have adequate plasma observations at kinetic scales to work on, but several studies, mostly numeric, have addressed this topic suggesting that discontinuities, small‐scale current sheets, and sites which are candidates for reconnection events might be regions where dissipative phenomena are at work with consequent plasma heating and acceleration. This review is intended to provide the reader with a quick overview on the past and most recent understanding of intermittency phenomenon in the solar wind from fluid to kinetic scales.
China's Urban Methane Emissions From Municipal Wastewater Treatment Plant
Authors: Zhao X. , Jin X. K. , Guo W. , Zhang C. , Shan Y. L. , Du M. X. , Tillotson M. R. , Yang H. , Liao X. W. , Li Y. P.
Published: April 2019

The increased number and capacity of municipal wastewater treatment plants (WWTPs) in China has driven the emission of methane (CH4). Few studies have focused on quantification of CH4 emissions from municipal WWTPs of different cities and analysis of socioeconomic factors influencing the quantity of emissions. Here we estimated CH4 emissions from WWTPs in China for 229 prefectural‐level cities, based on data from 2,019 working municipal WWTPs. The results show the total CH4 emissions to be 1,169.8 thousand tons (29.2 MtCO2e) in 2014, which is over three times that of the municipal WWTPs in the United States in 2016. Large cities along the east coast regions had larger CH4 emissions in absolute and per capita terms. Correlation analysis shows that cities with higher gross domestic product, household food consumption expenditure, or household consumption expenditure produced more degradable organics in wastewater, thus more CH4 emissions. Measures to control the sources of degradable organics and regulate WWTP processes with less emission factor are key to mitigate CH4 emissions. In addition to aerobic or anaerobic wastewater treatment systems, factors such as wastewater temperature, length of sewer, and the addition of nitrate that influencing emission factor are suggested to be involved in CH4 emission modeling.
The UT Variation of the Polar Ionosphere Based on COSMIC Observations
Authors: Wu Ye‐Wen , Liu Rui‐Yuan , Zhang Bei‐Chen , Wang Wen‐Bin , Zhang Shun‐Rong , Zhang Qing‐He , Hu Hong‐Qiao , Lu Jian‐Yong
Published: April 2019

Mean polar electron content (mPEC) is used to analyze the polar ionosphere in both the Antarctic and Arctic. The mPEC is calculated over the polar region covering geographic latitudes higher than 60° from the global distributed vertical total electron contents based on electron density profiles observed by Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC). Using this parameter, the universal time (UT) variation of the polar ionosphere is quantitatively characterized. This UT variation exists an opposite phase (i.e., a 12‐hr phase difference) between them. The mPEC standard deviation (SD) in the Antarctic is larger in summer and autumn (being 1.37 and 0.78 TECu, respectively) and smaller in winter (0.29 TECu) and spring (0.61 TECu). The SD in the Arctic, however, is the largest in winter (0.14 TECu). In other seasons, the SD is less than 0.1 TECu. (being 0.07 TECu in spring, 0.05 TECu in summer, and 0.08 TECu in autumn, respectively). We use SD over the mean value to describe relative intensity of mPEC variations. This relative intensity is larger in winter for both Antarctic and Arctic regions. The UT variation in intensity is much stronger in the Antarctic than in the Arctic. These characteristics are attributed to the fact that the separation of the geomagnetic pole and geographic pole is dihedral and the angle is larger in the Antarctic. The larger angle causes more electrons transported into the polar region when the geomagnetic pole is on the dayside and fewer electrons transported into the polar region when the geomagnetic pole is on the nightside.
Multidecadal Wind Variability Drives Temperature Shifts on the Agulhas Bank
Authors: Malan Neil , Durgadoo Jonathan V. , Biastoch Arne , Reason Chris , Hermes Juliet
Published: April 2019

The Agulhas Bank is an important area for the spawning of small pelagic fish and other species. Here, within a NEMO ocean model, we investigate changes in temperature over the Bank on multidecadal time scales. In agreement with previous observational studies, a shift to colder temperatures is found in 1997. The model also simulates an earlier shift from colder to warmer temperatures in 1966. These shifts are coastally confined and shown, using a climatologically forced model run as a control, to be driven by a north‐south migration in the large‐scale wind belts, rather than by changes in downward heat fluxes or changes in the Agulhas Current itself. The zonal wind changes on the Agulhas Bank show a significant relationship with the Southern Annular Mode, showing some promise for future predictability of cold and warm regimes on the Agulhas Bank. Thus, while the Agulhas Current has been shown in previous work to have a large impact on intra‐annual and interannual temperature variability, this work shows that multidecadal variability in temperature on the shelf is likely to be wind forced.
Submesoscale Surface Tidal, Vortical, and Residual Circulations in a Semienclosed Bay
Authors: Won Sang In , Kim Sung Yong , Kim Kyeong Ok
Published: April 2019

We scrutinize three different components of submesoscale surface tidal, vortical, and residual circulations in a semienclosed bay using (1) observations of high‐frequency radar‐derived surface current maps and (2) numerical model simulations run under realistic vertical stratification and boundary conditions at O(1)‐km spatial and 1‐hourly temporal resolutions over a 2‐year period (2013‐2014). The tidal circulation is characterized by (1) the tidal ellipses and spectral contents having more baroclinic motions at the M2 and S2 frequencies and more barotropic motions at the K1 frequency and (2) the temporal and spatial variability in the tidal fronts appearing as tidal ellipses with clustered shapes and opposite rotational directions. The regional vortical circulation is presented with the submesoscale eddies at diameters ranging from 3 to 12 km and normalized vorticity magnitudes of 0.2 to 2 for both clockwise and counterclockwise rotations. Based on the spatial statistics of the identified submesoscale eddies and eddy kinetic energy budget analysis, the submesoscale eddies are primarily generated by the detachment of shoreline‐following tidal currents at the coastal boundaries, persist for less than 1.5 days, and are dissipated dominantly via vertical buoyancy fluxes associated with bottom bathymetric interactions of the tidal currents. The residual circulation is clearly shown with the nontidal geostrophic currents associated with the pressure gradients generated by wind‐driven Ekman transports against the coast and the ageostrophic low‐frequency currents.
Detection of Mixed‐Phase Convective Clouds by a Binary Phase Information From the Passive Geostationary Instrument SEVIRI
Authors: Coopman Q. , Hoose C. , Stengel M.
Published: April 2019

Between −37 and 0 °C, clouds are liquid, ice, or mixed phase. Nearly all retrieval algorithms for passive instruments provide binary phase information—ice or liquid—making it difficult to retrieve mixed‐phase cloud properties. Based on measurements from the geostationary space‐based instrument Spinning Enhanced Visible and InfraRed Imager (SEVIRI), we show that the retrieved ice crystal effective radius is smaller than the liquid droplet effective radius for 48% of 230 analyzed cloud thermodynamic phase transitions—phase transition from liquid to ice of rising convective clouds—while ice crystals are expected to be larger than cloud droplets. We simulate mixed‐phase cloud radiances with the numerical model Santa Barbara DISORT Atmospheric Radiative Transfer for which we compare simulated effective radius retrievals with observations. The phase retrieval algorithm from SEVIRI does not represent well mixed‐phase clouds, and categorizing clouds by only ice and liquid is not enough to accurately represent mixed‐phase cloud optical properties. We conclude that the mixed‐phase nature of clouds explains that retrieved cloud droplet radii are larger than ice crystal radii directly before and after the phase transition. However, from a cloud tracking algorithm perspective, the variation of the effective radius enables the detection of mixed‐phase convective clouds from binary phase information.
Distinct Source Water Chemistry Shapes Contrasting Concentration‐Discharge Patterns
Authors: Zhi Wei , Li Li , Dong Wenming , Brown Wendy , Kaye Jason , Steefel Carl , Williams Kenneth H.
Published: April 2019

Understanding concentration‐discharge (C‐Q) relationships are essential for predicting chemical weathering and biogeochemical cycling under changing climate and anthropogenic conditions. Contrasting C‐Q relationships have been observed widely, yet a mechanistic framework that can interpret diverse patterns remains elusive. This work hypothesizes that seemingly disparate C‐Q patterns are driven by switching dominance of end‐member source waters and their chemical contrasts arising from subsurface biogeochemical heterogeneity. We use data from Coal Creek, a high‐elevation mountainous catchment in Colorado, and a recently developed watershed reactive transport model (BioRT‐Flux‐PIHM). Sensitivity analysis and Monte‐Carlo simulations (500 cases) show that reaction kinetics and thermodynamics and distribution of source materials across depths govern the chemistry gradients of shallow soil water and deeper groundwater entering the stream. The alternating dominance of organic‐poor yet geo‐solute‐rich groundwater under dry conditions and organic‐rich yet geo‐solute‐poor soil water during spring melt leads to the flushing pattern of dissolved organic carbon and the dilution pattern of geogenic solutes (e.g., Na, Ca, and Mg). In addition, the extent of concentration contrasts regulates the power law slopes (b) of C‐Q patterns via a general equation. At low ratios of soil water versus groundwater concentrations (Cratio = Csw/Cgw < 0.6), dilution occurs; at high ratios (Cratio > 1.8), flushing arises; chemostasis occurs in between. This equation quantitatively interpretsbvalues of 11 solutes (dissolved organic carbon, dissolved P, NO3−, K, Si, Ca, Mg, Na, Al, Mn, and Fe) from three catchments (Coal Creek, Shale Hills, and Plynlimon) of differing climate, geologic, and land cover conditions. This indicates potentially broad regulation of subsurface biogeochemical heterogeneity in determining C‐Q patterns and wide applications of this equation in quantifyingbvalues, which can have broad implications for predicting chemical weathering and biogeochemical transformation at the watershed scale.
Seismic Evidence for Lithospheric Thinning and Heat in the northern Canadian Cordillera
Authors: Audet Pascal , Currie Claire A. , Schaeffer Andrew J. , Hill Alexander M.
Published: April 2019

Geophysical and geological data indicate that the lithosphere in the northern Canadian Cordillera (NCC) is thin and hot. However, lack of direct constraints on mantle structure is fueling debates on the origin and nature of this lithosphere. Here we image the crust and uppermost mantle beneath the NCC and resolve the Moho at ~35‐km depth, the lithosphere‐asthenosphere boundary ~15 km deeper, and a westward dipping structure in the mantle below the eastern NCC. We examine end‐member tectonic models where the thin lithosphere is either long‐lived or has been rejuvenated by gravitational removal. In the long‐lived model, steady state thermal calculations indicate a Moho at ~1,000 °C; alternatively, time‐dependent calculations suggest that a removal event 5–25 Myr ago reproduces the seismic constraints. Combined with geologic evidence, these results suggest that the mantle lithosphere beneath the NCC is either exotic or the result of progressive thickening and cooling since the Miocene.
Quasi Thermal Noise Spectroscopy for Van Allen Probes
Authors: Yoon Peter H. , Hwang Junga , Kim Hyangpyo , Seough Jungjoon
Published: April 2019

Quasi thermal fluctuations in the Langmuir/upper‐hybrid frequency range are pervasively observed in space plasmas including the radiation belt and the ring current region of inner magnetosphere as well as the solar wind. The quasi thermal noise spectroscopy may be employed in order to determine the electron density and temperature as well as to diagnose the properties of energetic electrons when direct measurements are not available. However, when employing the technique, one must carefully take the spacecraft orientation into account. The present paper takes the upper‐hybrid and multiple harmonic—or (n + 1/2)fce—emissions measured by the Van Allen Probes as an example in order to illustrate how the spacecraft antenna geometrical factor can be incorporated into the theoretical interpretation. This method can in principle be applied to other spacecraft, including the Parker Solar Probe.
TRAF2 protects against cerebral ischemia-induced brain injury by suppressing necroptosis
Authors: Li Jie , Zhang Jingyu , Zhang Yusuo , Wang Zichuang , Song Yanmei , Wei Shanwen , He Meijun , You Shoujiang , Jia Jia , Cheng Jian
Published: April 2019

Necroptosis contributes to ischemia-induced brain injury. Tumor necrosis factor (TNF) receptor associated factor 2 (TRAF2) has been reported to suppress necroptotic cell death under several pathological conditions. In this study, we investigated the role of TRAF2 in experimental stroke using a mouse middle cerebral artery occlusion (MCAO) model and in vitro cellular models. TRAF2 expression in the ischemic brain was assessed with western blot and real-time RT-PCR. Gene knockdown of TRAF2 by lentivirus was utilized to investigate the role of TRAF2 in stroke outcomes. The expression of TRAF2 was significantly induced in the ischemic brain at 24 h after reperfusion, and neurons and microglia were two of the cellular sources of TRAF2 induction. Striatal knockdown of TRAF2 increased infarction size, cell death, microglial activation and the expression of pro-inflammatory markers at 24 h after reperfusion. TRAF2 expression and necroptosis were induced in mouse primary microglia treated with conditioned medium collected from neurons subject to oxygen and glucose deprivation (OGD) and in TNFα-treated mouse hippocampal neuronal HT-22 cells in the presence of the pan-caspase inhibitor Z-VAD. In addition, TRAF2 knockdown exacerbated microglial cell death and neuronal cell death under these conditions. Moreover, pre-treatment with a specific necroptosis inhibitor necrostatin-1 (nec-1) suppressed the cell death exacerbated by TRAF2 knockdown in the brain following MCAO, indicating that TRAF2 impacted ischemic brain damage through necroptosis mechanism. Taken together, our results demonstrate that TRAF2 is a novel regulator of cerebral ischemic injury.
Blockade of HMGB1 signaling pathway by ethyl pyruvate inhibits tumor growth in diffuse large B-cell lymphoma
Authors: Zhang Tian , Guan Xu-Wen , Gribben John G. , Liu Feng-Ting , Jia Li
Published: April 2019

High mobility group box 1 (HMGB1) protein in the tumor microenvironment actively contributes to tumor progression but its role in diffuse large B-cell lymphoma (DLBCL) is unknown. The aim of this study was to determine the mechanism by which HMGB1 promotes tumor growth in DLBCL and whether blockade of HMGB1 signaling pathway could inhibit tumorigenesis. We report that HMGB1 promotes proliferation of DLBCL cells by activation of AKT, extracellular signal-regulated kinases 1/2 (ERK1/2), signal transducer and activator of transcription 3 (STAT3) and SRC Proto-Oncogene, Non-Receptor Tyrosine Kinase (Src). Ethyl pyruvate (EP), an anti-inflammatory agent, inhibits HMGB1 active release from DLBCL cells and significantly inhibited proliferation of DLBCL cells in vitro. Treatment with EP significantly prevented and inhibited tumor growth in vivo and prolonged DLBCL-bearing mice survival. EP significantly downregulated HMGB1 expression and phosphorylation of Src and ERK1/2 in mice lymphoma tissue. EP induced accumulation of the cell cycle inhibitor p27 but downregulated expression of cyclin-dependent kinase 2 (CDK2). Increased nuclear translocation of p27 interacted with CDK2 and cyclin A, which led to blockade of cell cycle progression at the G1 to S phase transition. In conclusion, we demonstrated for the first time that blockade of HMGB1-mediated signaling pathway by EP effectively inhibited DLBCL tumorigenesis and disease progression.
A space–time tradeoff for implementing a function with master equation dynamics
Authors: Wolpert David H. , Kolchinsky Artemy , Owen Jeremy A.
Published: April 2019

Master equations are commonly used to model the dynamics of physical systems, including systems that implement single-valued functions like a computer’s update step. However, many such functions cannot be implemented by any master equation, even approximately, which raises the question of how they can occur in the real world. Here we show how any function over some “visible” states can be implemented with master equation dynamics—if the dynamics exploits additional, “hidden” states at intermediate times. We also show that any master equation implementing a function can be decomposed into a sequence of “hidden” timesteps, demarcated by changes in what state-to-state transitions have nonzero probability. In many real-world situations there is a cost both for more hidden states and for more hidden timesteps. Accordingly, we derive a “space–time” tradeoff between the number of hidden states and the number of hidden timesteps needed to implement any given function.
Spin-current-mediated rapid magnon localisation and coalescence after ultrafast optical pumping of ferrimagnetic alloys
Authors: Iacocca E. , Liu T.-M. , Reid A. H. , Fu Z. , Ruta S. , Granitzka P. W. , Jal E. , Bonetti S. , Gray A. X. , Graves C. E. , Kukreja R. , Chen Z. , Higley D. J. , Chase T. , Le Guyader L. , Hirsch K. , Ohldag H. , Schlotter W. F. , Dakovski G. L. , Coslovich G. , Hoffmann M. C. , Carron S. , Tsukamoto A. , Kirilyuk A. , Kimel A. V. , Rasing Th. , Stöhr J. , Evans R. F. L. , Ostler T. , Chantrell R. W. , Hoefer M. A. , Silva T. J. , Dürr H. A.
Published: April 2019

Sub-picosecond magnetisation manipulation via femtosecond optical pumping has attracted wide attention ever since its original discovery in 1996. However, the spatial evolution of the magnetisation is not yet well understood, in part due to the difficulty in experimentally probing such rapid dynamics. Here, we find evidence of a universal rapid magnetic order recovery in ferrimagnets with perpendicular magnetic anisotropy via nonlinear magnon processes. We identify magnon localisation and coalescence processes, whereby localised magnetic textures nucleate and subsequently interact and grow in accordance with a power law formalism. A hydrodynamic representation of the numerical simulations indicates that the appearance of noncollinear magnetisation via optical pumping establishes exchange-mediated spin currents with an equivalent 100% spin polarised charge current density of 107 A cm−2. Such large spin currents precipitate rapid recovery of magnetic order after optical pumping. The magnon processes discussed here provide new insights for the stabilization of desired meta-stable states.
Spy&Go purification of SpyTag-proteins using pseudo-SpyCatcher to access an oligomerization toolbox
Authors: Khairil Anuar Irsyad N. A. , Banerjee Anusuya , Keeble Anthony H. , Carella Alberto , Nikov Georgi I. , Howarth Mark
Published: April 2019

Peptide tags are a key resource, introducing minimal change while enabling a consistent process to purify diverse proteins. However, peptide tags often provide minimal benefit post-purification. We previously designed SpyTag, forming an irreversible bond with its protein partner SpyCatcher. SpyTag provides an easy route to anchor, bridge or multimerize proteins. Here we establish Spy&Go, enabling protein purification using SpyTag. Through rational engineering we generated SpyDock, which captures SpyTag-fusions and allows efficient elution. Spy&Go enabled sensitive purification of SpyTag-fusions from Escherichia coli, giving superior purity than His-tag/nickel-nitrilotriacetic acid. Spy&Go allowed purification of mammalian-expressed, N-terminal, C-terminal or internal SpyTag. As an oligomerization toolbox, we established a panel of SpyCatcher-linked coiled coils, so SpyTag-fusions can be dimerized, trimerized, tetramerized, pentamerized, hexamerized or heptamerized. Assembling oligomers for Death Receptor 5 stimulation, we probed multivalency effects on cancer cell death. Spy&Go, combined with simple oligomerization, should have broad application for exploring multivalency in signaling.
Serine 25 phosphorylation inhibits RIPK1 kinase-dependent cell death in models of infection and inflammation
Authors: Dondelinger Yves , Delanghe Tom , Priem Dario , Wynosky-Dolfi Meghan A. , Sorobetea Daniel , Rojas-Rivera Diego , Giansanti Piero , Roelandt Ria , Gropengiesser Julia , Ruckdeschel Klaus , Savvides Savvas N. , Heck Albert J. R. , Vandenabeele Peter , Brodsky Igor E. , Bertrand Mathieu J. M.
Published: April 2019

RIPK1 regulates cell death and inflammation through kinase-dependent and -independent mechanisms. As a scaffold, RIPK1 inhibits caspase-8-dependent apoptosis and RIPK3/MLKL-dependent necroptosis. As a kinase, RIPK1 paradoxically induces these cell death modalities. The molecular switch between RIPK1 pro-survival and pro-death functions remains poorly understood. We identify phosphorylation of RIPK1 on Ser25 by IKKs as a key mechanism directly inhibiting RIPK1 kinase activity and preventing TNF-mediated RIPK1-dependent cell death. Mimicking Ser25 phosphorylation (S > D mutation) protects cells and mice from the cytotoxic effect of TNF in conditions of IKK inhibition. In line with their roles in IKK activation, TNF-induced Ser25 phosphorylation of RIPK1 is defective in TAK1- or SHARPIN-deficient cells and restoring phosphorylation protects these cells from TNF-induced death. Importantly, mimicking Ser25 phosphorylation compromises the in vivo cell death-dependent immune control of Yersinia infection, a physiological model of TAK1/IKK inhibition, and rescues the cell death-induced multi-organ inflammatory phenotype of the SHARPIN-deficient mice.
Publisher Correction: Network-based prediction of drug combinations
Authors: Cheng Feixiong , Kovács István A. , Barabási Albert-László
Published: April 2019

The original version of this Article contained an error in Acknowledgements, which incorrectly omitted the following: ‘This work was also supported by NHLBI grant P01HL132825 to A.-L.B.’ This has been corrected in both the PDF and HTML versions of the Article.
CDK12 loss in cancer cells affects DNA damage response genes through premature cleavage and polyadenylation
Authors: Krajewska Malgorzata , Dries Ruben , Grassetti Andrew V. , Dust Sofia , Gao Yang , Huang Hao , Sharma Bandana , Day Daniel S. , Kwiatkowski Nicholas , Pomaville Monica , Dodd Oliver , Chipumuro Edmond , Zhang Tinghu , Greenleaf Arno L. , Yuan Guo-Cheng , Gray Nathanael S. , Young Richard A. , Geyer Matthias , Gerber Scott A. , George Rani E.
Published: April 2019

Cyclin-dependent kinase 12 (CDK12) modulates transcription elongation by phosphorylating the carboxy-terminal domain of RNA polymerase II and selectively affects the expression of genes involved in the DNA damage response (DDR) and mRNA processing. Yet, the mechanisms underlying such selectivity remain unclear. Here we show that CDK12 inhibition in cancer cells lacking CDK12 mutations results in gene length-dependent elongation defects, inducing premature cleavage and polyadenylation (PCPA) and loss of expression of long (>45 kb) genes, a substantial proportion of which participate in the DDR. This early termination phenotype correlates with an increased number of intronic polyadenylation sites, a feature especially prominent among DDR genes. Phosphoproteomic analysis indicated that CDK12 directly phosphorylates pre-mRNA processing factors, including those regulating PCPA. These results support a model in which DDR genes are uniquely susceptible to CDK12 inhibition primarily due to their relatively longer lengths and lower ratios of U1 snRNP binding to intronic polyadenylation sites.
Optimizing the conservation of migratory species over their full annual cycle
Authors: Schuster Richard , Wilson Scott , Rodewald Amanda D. , Arcese Peter , Fink Daniel , Auer Tom , Bennett Joseph. R.
Published: April 2019

Limited knowledge of the distribution, abundance, and habitat associations of migratory species hinders effective conservation actions. We use Neotropical migratory birds as a model group to compare approaches to prioritize land conservation needed to support ≥30% of the global abundances of 117 species. Specifically, we compare scenarios from spatial optimization models to achieve conservation targets by: 1) area requirements for conserving >30% abundance of each species for each week of the year independently vs. combined; 2) including vs. ignoring spatial clustering of species abundance; and 3) incorporating vs. avoiding human-dominated landscapes. Solutions integrating information across the year require 56% less area than those integrating weekly abundances, with additional reductions when shared-use landscapes are included. Although incorporating spatial population structure requires more area, geographical representation among priority sites improves substantially. These findings illustrate that globally-sourced citizen science data can elucidate key trade-offs among opportunity costs and spatiotemporal representation of conservation efforts.
Towards reliable extreme weather and climate event attribution
Authors: Bellprat Omar , Guemas Virginie , Doblas-Reyes Francisco , Donat Markus G.
Published: April 2019

Climate change is shaping extreme heat and rain. To what degree human activity has increased the risk of high impact events is of high public concern and still heavily debated. Recent studies attributed single extreme events to climate change by comparing climate model experiments where the influence of an external driver can be included or artificially suppressed. Many of these results however did not properly account for model errors in simulating the probabilities of extreme event occurrences. Here we show, exploiting advanced correction techniques from the weather forecasting field, that correcting properly for model probabilities alters the attributable risk of extreme events to climate change. This study illustrates the need to correct for this type of model error in order to provide trustworthy assessments of climate change impacts.
Mechanism of the electroneutral sodium/proton antiporter PaNhaP from transition-path shooting
Authors: Okazaki Kei-ichi , Wöhlert David , Warnau Judith , Jung Hendrik , Yildiz Özkan , Kühlbrandt Werner , Hummer Gerhard
Published: April 2019

Na+/H+ antiporters exchange sodium ions and protons on opposite sides of lipid membranes. The electroneutral Na+/H+ antiporter NhaP from archaea Pyrococcus abyssi (PaNhaP) is a functional homolog of the human Na+/H+ exchanger NHE1, which is an important drug target. Here we resolve the Na+ and H+ transport cycle of PaNhaP by transition-path sampling. The resulting molecular dynamics trajectories of repeated ion transport events proceed without bias force, and overcome the enormous time-scale gap between seconds-scale ion exchange and microseconds simulations. The simulations reveal a hydrophobic gate to the extracellular side that opens and closes in response to the transporter domain motion. Weakening the gate by mutagenesis makes the transporter faster, suggesting that the gate balances competing demands of fidelity and efficiency. Transition-path sampling and a committor-based reaction coordinate optimization identify the essential motions and interactions that realize conformational alternation between the two access states in transporter function.