bluuebunny/crossref_metadata_2025 huggingface dataset:
Tree hollow densities reduced by frequent late dry-season wildfires in threatened Gouldian finch (
Authors: Radford I. J. , Oliveira S. L. J. , Byrne B. , Woolley L.-A.
Published: April 2021

Abstract Context. Tree hollows are a key habitat resource for hollow-nesting species, including the northern Australian Gouldian finch (Erythrura gouldiae). Certain fire and disturbance regimes limit tree hollow availability in the northern Australian savannas. Aims. This study investigated the influence of fire regime and vegetation structure on the density of tree hollows at Gouldian finch breeding sites. Methods. Fire scars were mapped across breeding sites by using LANDSAT images. Vegetation plots within sites were spatially stratified according to three fire-regime attributes, namely, fire frequency, late dry-season wildfire frequency and time since the last fire. Tree hollow and vegetation structural attributes were measured at each vegetation plot. We modelled the relationship among hollow density, fire and vegetation attributes by using general linear mixed models with site as the random factor. Key results. We found that the highest tree-hollow density was found at plots with high eucalypt tree density and cover and with the lowest frequency of late dry-season wildfires (<1 wildfire over 5 years). Tree-hollow density declined after >2 years without fire. Hollow density was not directly related to total fire frequency. Conclusions. This study adds to previous work on grass seed resources in highlighting the importance of fire in Gouldian finch ecology. This study particularly highlighted the importance of reducing the impacts of high-intensity late dry-season wildfires because of their negative impacts on tree-hollow density, which is a key resource for breeding Gouldian finches. Implications. We recommend the use of a network of interconnected annual patchy early dry-season prescribed burns for protecting Gouldian breeding habitat from threat of high-intensity wildfires. We do NOT recommend fire exclusion from Gouldian finch breeding habitats. This is because fire risks to hollow-bearing trees, and grass seed resources, increase with the long-term accumulation of savanna litter fuels in the absence of fire.
Two sources of uncertainty independently modulate temporal expectancy
Authors: Grabenhorst Matthias , Maloney Laurence T. , Poeppel David , Michalareas Georgios
Published: April 2021

Significance

Biological organisms seek to reduce the uncertainty surrounding future events. Every possible event carries two distinct kinds of uncertainty: Will the event happen? And if it will happen, when exactly? It is commonly believed that the probability of whether an event occurs has a static effect on expectancy. However, here, we demonstrate that the effect is highly dynamic across time. We further show that the uncertainties about whether and when an event will occur independently shape anticipatory behavior. The results deepen our understanding of how the human brain interacts with the temporal structure of its environment.
Highly efficient photosynthesis of hydrogen peroxide in ambient conditions
Authors: Ye Yu-Xin , Pan Jinhui , Xie Fangyan , Gong Li , Huang Siming , Ke Zhuofeng , Zhu Fang , Xu Jianqiao , Ouyang Gangfeng
Published: April 2021

Significance

Advanced oxidation processes (AOPs) are widely applied to the treatment of refractory organic pollutants in the environment. However, the continuous addition of oxidant limits their application for in situ remediation of river courses. Hydrogen peroxide (H
2
O
2
) is the most commonly used oxidant in AOPs. Photosynthesis of H
2
O
2
is a promising approach to provide oxidants for AOPs in an in situ and continuous way. However, limited by the rapid charge recombination, organic electron donors and O
2
atmosphere are usually required. Here, a Z-scheme heterojunction photocatalyst achieved the production of H
2
O
2
in pure water and open air. The regulation and potential mechanism of the Z-scheme and type II heterojunctions are revealed. This study demonstrates a feasible strategy for developing efficient Z-scheme photocatalysts.
Fusarium oxysporum f.sp. niveum (Fusarium wilt of watermelon).
Authors: Keinath Anthony
Published: April 2021

Fusarium wilt of watermelon occurs throughout the world and is often a limiting factor in watermelon production. In China, 20-30% of watermelon production is normally lost in infested areas, and 100% mortality has been observed in fields planted with susceptible cultivars in Zhejiang Province (Lin, 1990). In a survey of 62 watermelon crops grown in plastic tunnels throughout the main production area of Cyprus, Fusarium wilt was found in all fields sampled despite the use of resistant cultivars (mainly Crimson Sweet). Mean incidence ranged from 37 to 70% in 1985 and 1986, and mean yields of marketable fruit were 38 and 10 t/ha, respectively (Ioannou and Poullis, 1991). In Aydin Province, Turkey, incidence ranged from 0.2 to 12% in fields in which the pathogen was isolated from symptomatic plants (Erİncİk and Döken, 2018). In Spain, in soil infested with unidentified races of F. oxysporum f.sp. niveum, yield loss in a triploid cultivar was 42 to 68% (Miguel et al., 2004). In South Carolina and Georgia, USA, yield losses in research fields naturally infested with race 2 averaged 62 and 83%, respectively, which represented a 91 and 55% loss in net returns per hectare, respectively, based on an average price of $USD 0.35 per kilogram of seedless watermelon fruit (Keinath et al., 2019a).
Inga punctata (ice cream bean tree).
Authors: Dube Shruti
Published: April 2021

A datasheet on Inga punctata covering, as an economically important tree, its taxonomy, importance, silviculture, distribution, biology and ecology, uses, products and pests.
Acer rufinerve (grey snake-bark maple).
Authors: Branquart Etienne , Vanderhoeven Sonia , Groom Quentin , Tanaka Hiroshi
Published: April 2021

A datasheet on Acer rufinerve covering, as an economically important tree, its taxonomy, importance, silviculture, distribution, biology and ecology, uses, products and pests.
Ligustrum vulgare (common privet).
Authors: Ziller Silvia
Published: April 2021

A datasheet on Ligustrum vulgare covering, as an economically important tree, its taxonomy, importance, silviculture, distribution, biology and ecology, uses, products and pests.
Piper aduncum (spiked pepper).
Authors: Padmanaba Michael
Published: April 2021

A datasheet on Piper aduncum covering, as an economically important tree, its taxonomy, importance, silviculture, distribution, biology and ecology, uses, products and pests.
Polyalthia suberosa (corky debbar tree).
Authors: Ventosa-Febles Eduardo A. , Cordero-Ramos Nicole
Published: April 2021

A datasheet on Polyalthia suberosa covering, as an economically important tree, its taxonomy, importance, silviculture, distribution, biology and ecology, uses, products and pests.
Vitex rotundifolia (beach vitex).
Authors: Jacono Colette
Published: April 2021

A datasheet on Vitex rotundifolia covering, as an economically important tree, its taxonomy, importance, silviculture, distribution, biology and ecology, uses, products and pests.
Breaching self-tolerance by targeting the gatekeeper
Authors: Wan Zurong , Pascual Virginia
Published: April 2021

Loss-of-function mutations in DNaseL13, the enzyme that restricts the amount of microparticle-associated DNA, cause SLE in humans and mice. In this issue of JEM, Hartl et al. (2021. J. Exp. Med.https://doi.org/10.1084/jem.20201138) uncover a reduction in plasma DNASE1L3 enzymatic activity due to the presence of autoantibodies in patients with nonfamilial SLE.
The Emerging Authority of Magistrate Judges within US District Courts
Authors: Boyd Christina L. , George Tracey E. , Yoon Albert H.
Published: April 2021

The federal judicial system is a hierarchy with district courts at the bottom, courts of appeals in the middle, and the Supreme Court at the top. A second, less visible, judicial hierarchy exists within district courts, with magistrate judges situated below district judges. Existing scholarship largely ignores magistrate judges, assuming they are agents tasked with procedural matters with little independent effect on federal courts adjudication. Using a combination of national administrative data (2000–2016) and original case-level data from nine district courts (1997–2014), we find that district courts not only grant meaningful responsibility and discretion to magistrate judges but do so in ways that vary substantially across and within districts. The effects of this judicial delegation extend from procedural rulings to substantive outcomes. Our findings provide evidence that a complete understanding of federal judicial decision making accounts for the roles—procedural and substantive—that magistrate judges perform.
Remarks on the factorization and monotonicity method for inverse acoustic scatterings
Authors: Furuya Takashi
Published: April 2021

We study the factorization and monotonicity method for inverse acoustic scattering problems. Firstly, we give a new general functional analysis theorem for the monotonicity method. Comparing with the factorization method, the general theorem of the monotonicity generates reconstruction schemes under weaker a priori assumptions for unknown targets, and can directly deal with mixed problems so that the unknown targets have several different boundary conditions. Using the general theorem, we give the reconstruction scheme for the mixed crack that the Dirichlet boundary condition is imposed on one side of the crack and the Neumann boundary condition on the other side, which is a new extension of the monotonicity method.
Role of Weyl cone tilting in the spin Hall effect of light
Authors: Liu Shuoqing , Yang Chenfei , Song Yifei , Tang Peng , Ke Yougang , Luo Zhaoming
Published: April 2021

We systematically study the role of Weyl cone tilting in the spin Hall effect of light (SHEL) in doped Weyl semimetals (WSMs), and propose a new scheme to determine the type of a WSM and to sense the tilt degree of Weyl cones precisely. It is found that in the case of a small amount of doping, the SHEL in type-I WSMs shows almost no dependence on the tilt degree of Weyl cones, while the SHEL in type-II WSMs is extremely sensitive to variations in the degree of tilt. However, in the case of a large amount of doping, not only the SHEL in type-II WSMs but also the SHEL in type-I WSMs show strong dependences on the tilt degree. These trends are mainly attributed to the variation of the real part of the Hall conductivity with the tilt degree. Remarkably, by using a quantum weak measurement, the tiny SHEL shifts can be amplified and detected to a desirable accuracy. Based on the obviously different tilt-dependent characteristics of amplified SHEL shifts in WSMs, we propose a new scheme to determine the type of a WSM and to sense the tilt degree precisely. By adjusting the doping level, the sensing sensitivity can reach up to 1461.55 µm per degree of tilt. This study may provide an application reference for the fabrication of WSM parameter sensors and other topological photoelectric devices.
Cytotoxicity of thermoresponsive core/shell Ni
x
Co1−

x
Fe2O4/PEG nanoparticles synthesized by the sol–gel method
Authors: Esmaeilkhanian Amirhossein , Sharifianjazi Fariborz , Parvin Nader , Kooti Mohammad Amin
Published: April 2021

These days, magnetic nanoparticles (MNPs), especially cobalt ferrite MNPs, have attracted the attention of many scientists in many applications, e.g. cancer treatment, due to their good magnetic properties. In this study, firstly the Ni
x
Co1−x
Fe2O4 MNPs (x = 0, 0.25, 0.5, and 0.75) were prepared through the sol–gel technique. The resulting particles were then coated with polyethylene glycol (PEG) polymer to obtain a core/shell structure. The x-ray diffraction and Fourier-transform infrared spectroscopy results illustrated that CoFe2O4 MNPs were successfully synthesized. Vibrating-sample magnetometer and (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bro-mide) assay results illustrated that the Ni0.5Co0.5Fe2O4 sample had the best saturation magnetization (71.68 emu g−1) and coercivity (∼500 Oe) values. Subsequently, the appropriate amount of PEG was found to be 15% wt/vol. The toxicity test showed that a concentration of 100 μg ml−1 of particles kept 96% of the cells alive. The particle size of the core/shelled MNPs was obtained to be ∼25 nm via a transmission electron microscopy image. Finally, it was observed that the Ni0.5Co0.5Fe2O4 sample coated with 15% wt/vol. PEG can be potentially used for hyperthermia.
Facile synthesis of nitrogen-doped and boron-doped reduced graphene oxide using radio-frequency plasma for supercapacitors
Authors: Wu Shilin , Zhang Cheng , Cui Xiaoyang , Zhang Shuai , Yang Qing , Shao Tao
Published: April 2021

Heteroatom doping is an effective method to improve the capacitive performance of graphene-based materials. In this work, a facile and efficient radio-frequency (RF) plasma treatment strategy has been employed to achieve simultaneous doping and reduction of graphene oxide (GO). As a result, boron-doped and nitrogen-doped reduced graphene oxide (denoted as B-rGO and N-rGO) have been synthesized rapidly under relatively low temperatures compared with conventional thermal methods. The B-rGO and N-rGO present significantly improved specific capacitances as high as 345 F g−1 and 365 F g−1 at 0.2 A g−1, respectively, exhibiting a fourfold increase compared to that of GO before plasma treatment. Interestingly, the N-rGO shows better rate capability than the B-rGO. Furthermore, the mechanism of simultaneous doping and reduction by RF plasma treatment is discussed based on the diagnosis of emission spectroscopy. The high energy electrons and plasma-excited ions and radicals render effective reduction, etching, and doping of GO at the same time. Compared with high-temperature carbonization and wet chemical methods, our plasma treatment method is more energy-saving and eco-friendly. We believe this rapid and straightforward plasma treatment method reported here can be extended to the incorporation of various heteroatoms into graphene lattice for broad applications.
A generalized molecule approach capturing the Feshbach-induced pairing physics in the BEC–BCS crossover
Authors: Cuestas Eloisa , Majtey Ana P
Published: April 2021

By including the effect of a trap with characteristic energy given by the Fermi temperature T
F in a two-body two-channel model for Feshbach resonances, we reproduce the measured binding energy of ultracold molecules in a 40K atomic Fermi gas. We also reproduce the experimental closed-channel fraction Z across the BEC–BCS crossover and into the BCS regime of a 6Li atomic Fermi gas. We obtain the expected behavior

Z
∝

T

F

at unitarity, together with the recently measured proportionality constant. Our results are also in agreement with recent measurements of the Z dependency on T
F on the BCS side, where a significant quantitative discrepancy between experimental data and theory’s predictions has been repeatedly reported. In order to contrast with future experiments we report the proportionality constant at unitarity between Z and

T

F

predicted by our model for a 40K atomic Fermi gas.
Chiral anomaly induced negative magnetoresistance and weak anti-localization in Weyl semimetal Bi0.97Sb0.03 alloy
Authors: Kumar P , Nagpal V , Sudesh  , Patnaik S
Published: April 2021

Experimental access to massless Weyl fermions through topological materials promises substantial technological ramifications. Here, we report magneto-transport properties of Bi1−x
Sb
x
alloy near the quantum critical point x = 3% and 3.5%. The two compositions that are synthesized and studied are single crystals of Bi0.97Sb0.03 and Bi0.965Sb0.035. We observe a transition from semimetal to semiconductor with the application of magnetic field in both specimens. An extremely large transverse magnetoresistance (MR) 1.8 × 105% and 8.2 × 104% at 2.5 K and 6 T is observed in Bi0.97Sb0.03 and Bi0.965Sb0.035, respectively. Kohler scaling of transverse MR reveals the crossover from low field quadratic MR to a high field linear MR at low temperatures in both samples. A decrease in longitudinal MR is observed only in Bi0.97Sb0.03 that implies the presence of chiral anomaly associated with the Weyl state at the crossover point (x = 0.03) in Bi1−x
Sb
x
system. The chiral anomaly is absent for the sample Bi0.965Sb0.035. A sharp increase in longitudinal resistivity for Bi0.97Sb0.03 close to zero magnetic fields indicates the weak anti-localization effect in Bi0.97Sb0.03. Extremely high carrier concentrations and high mobilities have been recorded for both the samples.
Topological plasmonic waveguides in triharmonic metal gratings
Authors: Smith Thomas Benjamin , Kocabas Coskun , Principi Alessandro
Published: April 2021

We study topological surface-plasmon-polaritons at optical frequencies in tri-harmonic diffraction gratings formed at a metal–dielectric interface. The latter are shown to well approximate a bipartite Kronig–Penney model. Topologically protected localised modes are then predicted to occur at the edges of the grating and at defects formed by the combination of two mirror antisymmetric corrugations, whose bulk invariant is a step-wise varying Zak phase in both cases. An interesting special case wherein the defect state is in-fact forbidden is also observed that reveals the fragility of such states despite their topological nature.
Highly active metal-free hetero-nanotube catalysts for the hydrogen evolution reaction
Authors: Li Wei , Choi Jin–Ho
Published: April 2021

The development of low-cost, high-efficiency catalysts for the hydrogen evolution reaction is important for hydrogen production. In this study we investigate hydrogen adsorption at the interfaces of C/BN hetero-nanotubes using first-principles density functional theory calculations. Substantial charge redistributions associated with states near the Fermi level occur at the interfaces. More importantly, such electronic modification can enhance hydrogen adsorption at the interfacial atoms. As a result, the adsorption free energies ΔG
H* of hydrogen for the interfaces range from −0.26 to 0.30 eV, depending on hydrogen coverage. These values are much closer to zero than those for the basal plane, suggesting that the interfaces could be active sites for the hydrogen evolution reaction. The interfacial adsorption sites show a distinctive hybridization between the H s and C p orbitals, which accounts for the enhanced hydrogen adsorption at the interfaces. These findings have important implications for hydrogen energy applications.
Particle tracking and beam optics analysis on a toroidal gantry for proton therapy
Authors: Felcini E , Bottura L , Gerbershagen A , van Nugteren J , Dutoit B
Published: April 2021

GaToroid is a concept of toroidal gantry for hadron therapy under investigation at CERN It makes use of the toroidal magnetic field between each pair of coils to steer and focus the particle beams down to the patient. This peculiar concept requires detailed studies on particle tracking and beam optics to optimise the winding geometry and explore the properties of the system. The work presented in this manuscript is focused on the features of a GaToroid system for protons, specifically designed to minimise the footprint and weight of the gantry. Firstly, a two-dimensional single particle tracking was developed to optimise the coil geometry and the toroidal magnetic field, aiming to the maximisation of the energy acceptance of the magnet. Particles over the whole spectrum of treatment energy are directed at isocenter within 1 mm of precision. This procedure, restricted to the symmetry plane between each pair of coils, defines different beam orbits, function of the beam energy. Subsequently, a three-dimensional particle tracking was implemented to evaluate the interaction of a beam of finite dimensions with the complete magnetic field map in vacuum. The parameters of the simulated beam at the isocenter are coherent with the clinical requirements. The results of the three-dimensional tracking were then used to calculate the linear transfer matrix associated to each beam orbit. Finally, the option of performing the beam spot scanning at the isocenter by acting on the upstream steering magnet has been investigated, highlighting the potential of the concept, as well as the limitations related to the scanning field dimension and source-to-axis distance. In conclusion, the results described in this paper represent a crucial step toward the understanding of the beam optics properties of a GaToroid gantry.
A numerical model for analysis of binary chemical reaction and activation energy of thermo solutal micropolar nanofluid flow through permeable stretching sheet: nanoparticle study
Authors: M D Shamshuddin , Mabood F
Published: April 2021

The mechanism of nanofluid to improve heat transfer features has received great consideration due to their wide applications in chemical engineering and industry. In light of these facts, a numerical simulation for the flow of a micropolar nanofluid with suspended nanoparticles has been analyzed past a permeable stretching sheet with non-uniform heat source/sink, Binary chemical reaction and activation energy. In modeling micropolar nanofluid quantifies and qualifies the thermal phenomena caused by convective heat transfer in the presence of non-uniform heat source/sink and reaction rate. The formulated equations are altered to ordinary differential equations by employing similarity transformations which are then solved by utilizing shooting technique and RKF-45 method. The potentialities of all the representatives are put into graphs and are elucidated. Furthermore, the skin friction coefficient and Nusselt number in the boundary layer regime, are exhibited through graphs and tables and are deliberated with proper physical justification. The significant outcomes of the current investigation are that increment in the suction parameter declines the flow velocity and temperature while the injection is uplift the temperature. The skin friction factor is trigger considerable decrease with the stretching parameter. The heat transfer rate increases with the increased values of the radiation parameter.
Localized waves carrying orbital angular momentum in optical fibers
Authors: Nuño Ruano Paula , Robson Charles W , Ornigotti Marco
Published: April 2021

We consider the effect of orbital angular momentum (OAM) on localized waves in optical fibers using theory and numerical simulations, focusing on splash pulses and focus wave modes. For splash pulses, our results show that they may carry OAM only up to a certain maximal value. We also examine how one can optically excite these OAM-carrying modes, and discuss potential applications in communications, sensing, and signal filtering.
Rationality of equivariant Hilbert series and asymptotic properties
Authors: Nagel Uwe
Published: April 2021

AnFI\operatorname {FI}- or anOI\operatorname {OI}-moduleM\mathbf {M}over a corresponding noetherian polynomial algebraP\mathbf {P}may be thought of as a sequence of compatible modulesMn\mathbf {M}_nover a polynomial ringPn\mathbf {P}_nwhose number of variables depends linearly onnn. In order to study invariants of the modulesMn\mathbf {M}_nin dependence ofnn, an equivariant Hilbert series is introduced ifM\mathbf {M}is graded. IfM\mathbf {M}is also finitely generated, it is shown that this series is a rational function. Moreover, if this function is written in reduced form rather precise information about the irreducible factors of the denominator is obtained. This is key for applications. It follows that the Krull dimension of the modulesMn\mathbf {M}_ngrows eventually linearly innn, whereas the multiplicity ofMn\mathbf {M}_ngrows eventually exponentially innn. Moreover, for any fixed degreejj, the vector space dimensions of the degreejjcomponents ofMn\mathbf {M}_ngrow eventually polynomially innn. As a consequence, any graded Betti number ofMn\mathbf {M}_nin a fixed homological degree and a fixed internal degree grows eventually polynomially innn. Furthermore, evidence is obtained to support a conjecture that the Castelnuovo-Mumford regularity and the projective dimension ofMn\mathbf {M}_nboth grow eventually linearly innn. It is also shown that modulesM\mathbf {M}whose widthnncomponentsMn\mathbf {M}_nare eventually Artinian can be characterized by their equivariant Hilbert series. Using regular languages and finite automata, an algorithm for computing equivariant Hilbert series is presented.
The N-terminal tail of C. elegans CENP-A interacts with KNL-2 and is essential for centromeric chromatin assembly
Authors: de Groot Christian , Houston Jack , Davis Bethany , Gerson-Gurwitz Adina , Monen Joost , Lara-Gonzalez Pablo , Oegema Karen , Shiau Andrew K. , Desai Arshad
Published: April 2021

Caenorhabditis elegans builds centromeres using the histone H3 variant CENP-A but lacks a CENP-A-specific chaperone. This article shows that the extended N-terminal tail of C. elegans CENP-A, which interacts with the conserved loading factor KNL-2 and is essential for loading, provides at least part of the function of the dedicated chaperone.
Impact of Intravenous Antihypertensives on Outcomes Among Hospitalized Patients
Authors: Bean-Thompson Kelsi , Exposito Julien , Fowler Oliver , Mhaskar Rahul , Chen Liwei , Codolosa Jose Nicolas
Published: April 2021

BACKGROUND

Many hospitalized patients with acute elevations in blood pressure (BP) are treated with intravenous (IV) antihypertensive medications without evidence of benefit. This study investigated the effects of IV as-needed (PRN) antihypertensives on BP, hospital length of stay, and mortality.

METHODS

We included hospitalized patients with an order for an IV PRN antihypertensive medication. We excluded patients with target organ damage. We performed multivariate analysis to assess whether the medication was independently associated with outcomes.

RESULTS

1,784 out of 5,680 patients (31%) had an administration of the PRN medication. Patients who received the medication had a longer hospital stay compared with patients with an order for the medication who did not receive it (4.9 ± 6.1 vs. 3.1 ± 4.1 days, P < 0.001). This remained statistically significant after adjusting for covariates. In-hospital mortality was higher in the group that received the medication (3.3% vs. 1.6%, P < 0.001), but this was not statistically significant on multivariate analysis. IV hydralazine caused the most significant reduction in BP and led to a shorter length of stay when compared with enalapril and labetalol. A total of 62% of patients received the medication for a systolic BP lower than 180 mm Hg.

CONCLUSIONS

Treating hypertension in the in-patient setting remains complex. Rapid lowering of BP can cause harm to patients, and this study showed that antihypertensive medication increased hospital length of stay. Once assuring no target organ damage, a strategic approach should be to treat modifiable factors and gradually reduce BP.
Impaired KCC2 Function Triggers Interictal-Like Activity Driven by Parvalbumin-Expressing Interneurons in the Isolated Subiculum In Vitro
Authors: Anstötz Max , Fiske Michael Patrick , Maccaferri Gianmaria
Published: April 2021

The decreased expression of the KCC2 membrane transporter in subicular neurons has been proposed to be a key epileptogenic event in temporal lobe epilepsy (TLE). Here, we have addressed this question in a reduced model in vitro and have studied the properties and mechanistic involvement of a major class of interneurons, that is, parvalbumin-expressing cells (PVs). When exposed to the KCC2 blocker VU0463271, mouse subicular slices generated hypersynchronous discharges that could be recorded electrophysiologically and visualized as clusters of co-active neurons with calcium imaging. The pharmacological profile of these events resembled interictal-like discharges in human epileptic tissue because of their dependence on GABAA and AMPA receptors. On average, PVs fired before pyramidal cells (PCs) and the area of co-active clusters was comparable to the individual axonal spread of PVs, suggesting their mechanistic involvement. Optogenetic experiments confirmed this hypothesis, as the flash-stimulation of PVs in the presence of VU0463271 initiated interictal-like discharges, whereas their optogenetic silencing suppressed network hyper-excitability. We conclude that reduced KCC2 activity in subicular networks in vitro is sufficient to induce interictal-like activity via altered GABAergic signaling from PVs without other epilepsy-related changes. This conclusion supports an epileptogenic role for impaired subicular KCC2 function during the progression of TLE.
Parsing Sage and Rosemary in Time: The Machine Learning Race to Crack Olfactory Perception
Authors: Gerkin Richard C
Published: April 2021

Color and pitch perception are largely understandable from characteristics of physical stimuli: the wavelengths of light and sound waves, respectively. By contrast, understanding olfactory percepts from odorous stimuli (volatile molecules) is much more challenging. No intuitive set of molecular features is up to the task. Here in Chemical Senses, the Ray lab reports using a predictive modeling framework—first breaking molecular structure into thousands of features and then using this to train a predictive statistical model on a wide range of perceptual descriptors—to create a tool for predicting the odor character of hundreds of thousands of available but previously uncharacterized molecules (Kowalewski et al. 2021). This will allow future investigators to representatively sample the space of odorous molecules as well as identify previously unknown odorants with a target odor character. Here, I put this work into the context of other modeling efforts and highlight the urgent need for large new datasets and transparent benchmarks for the field to make and evaluate modeling breakthroughs, respectively.
Spatial autocorrelation method for reliable measurements of two-station dispersion curves in heterogeneous ambient noise wavefields
Authors: Ikeda Tatsunori , Tsuji Takeshi , Konishi Chisato , Saito Hideki
Published: April 2021

The microtremor survey method (MSM) is used to estimate S-wave velocity profiles from microtremors or ambient noise. Although array-based MSM analyses are usually used for shallow exploration purposes because of their robustness, the extraction of numerous phase-velocity dispersion curves by two-station microtremor analysis is attractive because those dispersion curves can be used to construct high-resolution phase-velocity maps by solving a least-squares problem. However, in exploration studies (>1 Hz), the reliability of two-station microtremor analysis can be affected by short data acquisition times and heterogeneous noise distributions mainly caused by anthropogenic noises. In this study, we propose a new approach to estimate surface wave dispersion curves between station pairs considering a heterogeneous ambient noise distribution based on the spatial autocorrelation method. We first estimated azimuthal variations of noise energy from the complex coherencies between all station pairs in a receiver array, and then estimated dispersion curves between station pairs. Our field example demonstrates that modelling the azimuthal noise energy distribution allows us to use not only the real parts of complex coherencies, but also the imaginary parts, which are usually neglected when assuming a homogeneous noise field. The simultaneous use of the real and imaginary parts of complex coherencies improves the reliability and continuity of phase-velocity estimations between station pairs. Because the stability of phase-velocity estimations depends on the azimuths between station pairs, we carefully selected between-station azimuths that produce stable phase velocities. Selected phase velocities at 8 Hz can be used to construct high-resolution phase-velocity maps with least-squares inversion. Because our approach does not require a regular receiver interval for two-station analysis, it allows for more flexible seismic array geometries. This is particularly important for MSM analyses in urban areas, where limited space is available to install seismic stations. We conclude that our proposed approach is effective in reconstructing high-resolution shallow structures in heterogeneous ambient noise fields.
The impact of physically active learning during the school day on children’s physical activity levels, time on task and learning behaviours and academic outcomes
Authors: Bacon Paul , Lord Rachel N
Published: April 2021

The benefits of physical activity in school settings and its impact on health and academic outcomes are of interest from public health and educational contexts. This study investigates how physically active learning (PAL): (i) contributes to children’s physical activity levels, (ii) impacts on academic outcomes and (iii) influences children’s focus and concentration, defined as time on task (ToT). Methods: Over a 2-week period, participants were exposed to PAL and non-active learning (NAL) lessons in a counterbalanced design. Physiological responses and ToT behaviour were recorded throughout PAL and NAL lessons. Academic outcomes were assessed the week before, during and the week after each mode of delivery. Results: Children were more active during PAL (196�542 steps per week) compared to NAL (152�395 steps per week, P = 0.003). The physiological demands of PAL (73% HRmax), were significantly greater (P < 0.001) than NAL (51% HRmax). Children’s ToT was significantly higher (P < 0.001) with PAL (97%) than NAL (87%). There were no differences in academic outcomes when PAL and NAL were compared. Conclusions: Modest levels of PAL increased activity levels. No evidence was found to suggest PAL had a negative effect on children’s academic outcomes, and PAL could positively impact on children’s concentration.
Swimming Kinematics of Cyprids of the Barnacle Balanus glandula
Authors: Lamont Eleanor I , Emlet Richard B
Published: April 2021

Synopsis

Larvae of barnacles typically pass through naupliar and cyprid planktonic stages before settlement and metamorphosis. As the final larval stage, cyprids swim much faster than nauplii and in turbulent fluid environments with high shears as they seek habitat. Cyprids swim with six pairs of reciprocating thoracic appendages and use two anterior antennules during settlement. Our understanding of how thoracic appendages generate movement is limited due to short stroke intervals (∼5 ms) that impede observations of the shape and trajectory of appendages. Here, we used high-speed videography to observe both free-swimming and tethered cyprids of the intertidal acorn barnacle Balanus glandula to produce a comprehensive description of thoracic appendage swimming kinematics. Cyprids used a drag-based method of swimming: their six pairs of thoracic appendages moved through metachronal power strokes and synchronous recovery strokes similar to the thoracopod motions in calanoid copepods during escape swimming. During the power stroke, plumose setae on each appendage pair spread laterally into a high surface area and high drag paddle composed of a meshwork of fused setules. This interconnected setal array collapsed into a low surface area and low drag shape during the recovery stroke. These effective swimming appendages allowed cyprids to move upward at an average speed of 1.4 cm/s (∼25 body lengths/s) with an average beat frequency of 16 beats/s, and reach an instantaneous velocity of up to 6 cm/s. Beat frequency of the thoracic appendages was significantly associated with speed, with higher beat frequencies indicating faster swimming speed. At their average speed, cyprids moved at the intermediate Reynolds number of ∼10, in which both viscous and inertial forces affected movement. Cyprids could alter swimming direction by sweeping the posterior-most appendage pair to one side and beating the remaining thoracic appendages synchronously through the power stroke with greater motion on the outside of their turn. These results greatly enhance our understanding both of cyprid motility and how small planktonic organisms can use swimming appendages with fused setule arrays to reach high swimming speeds and affect directional changes.
Double Quasi-Poisson Algebras are Pre-Calabi-Yau
Authors: Fernández David , Herscovich Estanislao
Published: April 2021

In this article, we prove that double quasi-Poisson algebras, which are noncommutative analogues of quasi-Poisson manifolds, naturally give rise to pre-Calabi-Yau algebras. This extends one of the main results in [11], where a correspondence between certain pre-Calabi-Yau algebras and double Poisson algebras was found (see also [13, 12, 10]). However, a major difference between the pre-Calabi-Yau algebra constructed in the mentioned articles and the one constructed in this work is that the higher multiplications indexed by even integers of the underlying $A_{\infty }$-algebra structure of the pre-Calabi-Yau algebra associated with double quasi-Poisson algebra do not vanish, but are given by nice cyclic expressions multiplied by explicitly determined coefficients involving the Bernoulli numbers.
Pneumocystis jirovecii Colonization in Preterm Newborns With Respiratory Distress Syndrome
Authors: Szydłowicz Magdalena , Królak-Olejnik Barbara , Vargas Sergio L , Zajączkowska Żaneta , Paluszyńska Dorota , Szczygieł Anna , Matos Olga , Hendrich Andrzej B , Kicia Marta
Published: April 2021

We describe the prevalence of Pneumocystis jirovecii in mother-infant pairs of very low birth weight newborns <32 weeks gestation. Molecular and microscopic methods were used for detection of P. jirovecii in patients’ specimens. Pneumocystis DNA was detected in 8 nasopharyngeal aspirates (14%) of 56 newborns and in 7 oral washes (21%) of 34 mothers. Pneumocystis detection immediately after birth suggests the possibility of its transplacental transmission. Compared to noncolonized infants, more frequent occurrence of bronchopulmonary dysplasia was seen in colonized infants (P = .02), suggesting a potential clinical importance of this pathogen in abnormal lung development.
A combined assay for quantifying remdesivir and its metabolite, along with dexamethasone, in serum
Authors: Reckers Andrew , Wu Alan H B , Ong Chui Mei , Gandhi Monica , Metcalfe John , Gerona Roy
Published: April 2021

Background

As global confirmed cases and deaths from coronavirus disease 2019 (COVID-19) surpass 100 and 2.2 million, respectively, quantifying the effects of the widespread treatment of remdesivir (GS-5734, Veklury) and the steroid dexamethasone is becoming increasingly important. Limited pharmacokinetic studies indicate that remdesivir concentrations in serum decrease quickly after dosing, so its primary serum metabolite GS-441524 may have more analytical utility.

Objectives

We developed and validated a method to quantify remdesivir, its metabolite GS-441524 and dexamethasone in human serum.

Methods

We used LC-MS/MS and applied the method to 23 serum samples from seven patients with severe COVID-19.

Results

The method has limits of detection of 0.0375 ng/mL for remdesivir, 0.375 ng/mL for GS-441524 and 3.75 ng/mL for dexamethasone. We found low intra-patient variability, but significant inter-patient variability, in remdesivir, GS-441524 and dexamethasone levels.

Conclusions

The significant inter-patient variability highlights the importance of therapeutic drug monitoring of COVID-19 patients and possible dose adjustment to achieve efficacy.
Search for dormant black holes in ellipsoidal variables – II. A binary modified minimum mass ratio
Authors: Gomel Roy , Faigler Simchon , Mazeh Tsevi
Published: April 2021

This is the second of a series of papers that focuses on searching large sets of photometric light curves for evidence of close binaries with a dormant black hole, and, in some cases, a dormant neutron star. The detection of such a binary is based on identifying a star that displays a large ellipsoidal periodic modulation, induced by tidal interaction with its companion. Based on the observed ellipsoidal amplitude and the primary mass and radius, one can derive a minimum mass ratio of the binary. A binary with a minimum mass ratio significantly larger than unity might be a candidate for having a dormant compact-object companion. Unfortunately, the photometric search is hampered by the fact that in many cases the primary mass and radius are not well known. In this paper we present a simple approach that circumvents this problem by suggesting a robust modified minimum mass ratio, assuming the primary fills its Roche lobe. The newly defined modified minimum mass ratio is always smaller than the minimum mass ratio, which is, in its turn, smaller than the actual mass ratio. Therefore, binaries with a modified minimum mass ratio larger than unity are candidates for having a compact-object secondary.
Predictive Models of Genetic Redundancy inArabidopsis thaliana
Authors: Cusack Siobhan A , Wang Peipei , Lotreck Serena G , Moore Bethany M , Meng Fanrui , Conner Jeffrey K , Krysan Patrick J , Lehti-Shiu Melissa D , Shiu Shin-Han
Published: April 2021

Genetic redundancy refers to a situation where an individual with a loss-of-function mutation in one gene (single mutant) does not show an apparent phenotype until one or more paralogs are also knocked out (double/higher-order mutant). Previous studies have identified some characteristics common among redundant gene pairs, but a predictive model of genetic redundancy incorporating a wide variety of features derived from accumulating omics and mutant phenotype data is yet to be established. In addition, the relative importance of these features for genetic redundancy remains largely unclear. Here, we establish machine learning models for predicting whether a gene pair is likely redundant or not in the model plant Arabidopsis thaliana based on six feature categories: functional annotations, evolutionary conservation including duplication patterns and mechanisms, epigenetic marks, protein properties including posttranslational modifications, gene expression, and gene network properties. The definition of redundancy, data transformations, feature subsets, and machine learning algorithms used significantly affected model performance based on holdout, testing phenotype data. Among the most important features in predicting gene pairs as redundant were having a paralog(s) from recent duplication events, annotation as a transcription factor, downregulation during stress conditions, and having similar expression patterns under stress conditions. We also explored the potential reasons underlying mispredictions and limitations of our studies. This genetic redundancy model sheds light on characteristics that may contribute to long-term maintenance of paralogs, and will ultimately allow for more targeted generation of functionally informative double mutants, advancing functional genomic studies.
Evolving origin-of-transfer sequences on staphylococcal conjugative and mobilizable plasmids—who’s mimicking whom?
Authors: Yui Eto Karina , Kwong Stephen M , LaBreck Patrick T , Crow Jade E , Traore Daouda A K , Parahitiyawa Nipuna , Fairhurst Heather M , Merrell D Scott , Firth Neville , Bond Charles S , Ramsay Joshua P
Published: April 2021

In Staphylococcus aureus, most multiresistance plasmids lack conjugation or mobilization genes for horizontal transfer. However, most are mobilizable due to carriage of origin-of-transfer (oriT) sequences mimicking those of conjugative plasmids related to pWBG749. pWBG749-family plasmids have diverged to carry five distinct oriT subtypes and non-conjugative plasmids have been identified that contain mimics of each. The relaxasome accessory factor SmpO, encoded by each conjugative plasmid, determines specificity for its cognate oriT. Here we characterized the binding of SmpO proteins to each oriT. SmpO proteins predominantly formed tetramers in solution and bound 5′-GNNNNC-3′ sites within each oriT. Four of the five SmpO proteins specifically bound their cognate oriT. An F7K substitution in pWBG749 SmpO switched oriT-binding specificity in vitro. In vivo, the F7K substitution reduced but did not abolish self-transfer of pWBG749. Notably, the substitution broadened the oriT subtypes that were mobilized. Thus, this substitution represents a potential evolutionary intermediate with promiscuous DNA-binding specificity that could facilitate a switch between oriT specificities. Phylogenetic analysis suggests pWBG749-family plasmids have switched oriT specificity more than once during evolution. We hypothesize the convergent evolution of oriT specificity in distinct branches of the pWBG749-family phylogeny reflects indirect selection pressure to mobilize plasmids carrying non-cognate oriT-mimics.
Microbial food web dynamics in the oceanic Gulf of Mexico
Authors: Landry Michael R , Selph Karen E , Stukel Michael R , Swalethorp Rasmus , Kelly Thomas B , Beatty Jennifer L , Quackenbush Cameron R
Published: April 2021

Phytoplankton growth and microzooplankton grazing rates were measured in repeated profiles of dilution experiments incubated in situ on a drift array in order to assess microbial production and food web characteristics in the oligotrophic bluefin tuna spawning habitat of the Gulf of Mexico (May peak spawning seasons, 2017–2018). Grazing often exceeded growth with the processes more balanced overall in the surface mixed layer, but biomass accumulated in the mid-euphotic zone. Community production estimates (260–500 mg C m−2 day−1) were low compared to similar open-ocean studies in the Pacific Ocean. Prochlorococcus was a consistent major contributor (113–204 mg C m−2 day−1) to productivity, while diatoms and dinoflagellates (2–10 and 4–13 mg C m−2 day−1, respectively) were consistently low. Prymnesiophytes, the most dynamic component (34–134 mg C m−2 day−1), co-dominated in 2017 experiments. Unexpected imbalances in grazing relative to production were observed for all picoplankton populations (Prochlorococcus, Synechococcus and heterotrophic bacteria), suggesting a trophic cascade in the absence of mesozooplankton predation on large microzooplankton. Study sites with abundant larval tuna had the shallowest deep chlorophyll maxima and significant net positive phytoplankton growth below the mixed layer.
Evaluation of revised classification criteria for giant cell arteritis and its clinical phenotypes
Authors: Wiberg Frans , Naderi Nazanin , Mohammad Aladdin J , Turesson Carl
Published: April 2021

Background

GCA is a systemic vasculitis of the elderly, viewed by many as a disease with multiple and overlapping clinical phenotypes. Retrospective studies have shown differences in clinical presentation between these phenotypes. To reflect the heterogeneity of GCA and novel diagnostic methods, new classification criteria have been proposed.

Methods

This is a retrospective study of newly diagnosed patients with GCA at the outpatient rheumatology clinics at Skåne University Hospital (Malmö and Lund) between 2012 and 2018. All patients were evaluated using two sets of classification criteria, the ACR classification criteria from 1990 and a proposed revision of these criteria requiring objective findings (positive biopsy or imaging) for classification. Patients were further classified as one of four widely used clinical phenotypes.

Results

A total of 183 patients with a new diagnosis of GCA were identified. The diagnosis was confirmed by one or two experienced rheumatologists in 116 of these patients during a review of medical records. The ACR criteria were more sensitive than the revised criteria (93.1% vs 72.4%), but the revised criteria had higher specificity (94.0% vs 28.4%). The revised criteria tended to have higher sensitivity in the phenotype with constitutional symptoms compared with cranial GCA (P = 0.08).

Conclusion

The specificity of the ACR classification criteria for GCA can be improved by using revised criteria requiring objective findings of vasculitis. In addition, the wider symptoms covered by the revised criteria may improve classification of patients with a phenotype characterized by constitutional symptoms.