bluuebunny/crossref_metadata_2025 huggingface dataset:
Clinical Picture, Outcome, and Risk of Serious Bacterial Infections in Immunocompetent Previously Healthy Neutropenic Children
Authors: Arslantaş Esra , Ayçiçek Ali , Türkoğlu Recep , Tahtakesen Tuba Nur , Uysalol Ezgi Paslı , Bayram Cengiz , Akici Ferhan , Şanlı Kamuran , Özdemir Nihal
Published: May 2021

Objective In childhood, the cause of neutropenia is a challenging diagnosis with a spectrum of underlying etiologies. This study was performed to investigate the clinical picture and the outcomes associated with the new onset neutropenia in previously healthy children, and to determine the risk of serious bacterial infection (SBI) in those patients.

Methods Patients presenting between January 2018 and September 2018 with an absolute neutrophil count (ANC) <1,500/μL were retrospectively evaluated. Patients with known underlying chronic disease or immunosuppressive conditions were excluded. Neutropenia was categorized into three groups: mild, 1,000–1,500/μL; moderate, 500 to <1,000/μL; and severe <500/μL.

Results A total of 423 patients were investigated. There were 156 (36.9%), 193 (45.6%), and 74 (17.5%) patients in the mild, moderate, and severe groups, respectively. Bacteremia was detected in one (0.02%) patient and SBI in 21 (4.9%) patients. No significant correlation was found between the incidence of SBI and bacterial infection rate among different age groups (p > 0.05). The incidence of SBI varied significantly according to the severity of the neutropenia (p = 0.012) and as the neutropenia became more severe, the incidence of SBI increased (p = 0.015).

Conclusion The clinical outcome of neutropenia in previously healthy and immunocompetent children is generally good with a relatively low incidence of SBI. We suggest that aggressive therapy and frequent follow-up should be reserved for previously healthy neutropenic children with SBI.
TBC1D24 and Its Related Epileptic Encephalopathy
Authors: Timpanaro Tiziana , La Mendola Flavia , Billone Sebastiano , Nora Alessandra Di , Collotta Ausilia , Sauna Alessandra , Salafia Stefania , Falsaperla Raffaele
Published: May 2021

TBC1D24, mapped to 16p13.3, encodes a protein containing a Tre2/Bub2/Cdc16 (TBC) domain, belonging to the super-family of Rab GTPase activating proteins (Rab-GAP). These proteins regulate various functions, including the regulation of the traffic of the vesicular membrane. Several TBC1D24 mutations have been related to autosomal recessive neurological disorders, including severe developmental encephalopathies with malignant early childhood epilepsy, benign epilepsy, epileptic encephalopathy, and a complex neurological syndrome characterized by deafness, onychodystrophy, bone and neurological degeneration. Mutations of TBC1D24 have also been reported in patients with nonsyndromic deafness with dominant or recessive inheritance. Mechanisms underlying TBC1D24-associated disorders and the functions of TBC1D24 products in the generation of such complex spectrum of diseases remain partly unclear and future studies are needed to clarify this aspect, in order to improve the management of seizures and for the prevention of complication (including death) of newly diagnosed patients affected by TBC1D24-related disorders.
KCNT1-Related Epilepsy: A Review
Authors: Venti Valeria , Ciccia Lina , Scalia Bruna , Sciuto Laura , Cimino Carla , Marino Simona , Praticò Andrea D. , Falsaperla Raffaele
Published: May 2021

KCNT1 gene encodes the sodium-dependent potassium channel reported as a causal factor for several different epileptic disorders. The gene has been also linked with cardiac disorders and in a family to sudden unexpected death in epilepsy. KCNT1 mutations, in most cases, result in a gain of function causing a neuronal hyperpolarization with loss of inhibition. Many early-onset epileptic encephalopathies related to gain of function of KCNT1 gene have been described, most often associated with two phenotypes: malignant migrating focal seizures of infancy and familial autosomal-dominant nocturnal frontal lobe epilepsy; however, there is no clear phenotype–genotype correlation, in fact same mutations have been represented in patients with West syndrome, Ohtahara syndrome, and early myoclonic encephalopathy. Additional neurologic features include intellectual disability, psychiatric disorders, hypotonia, microcephaly, strabismus, and movement disorders. Conventional anticonvulsant, vagal stimulation, and ketogenic diet have been used in the absence of clinical benefit in individuals with KCNT1-related epilepsy; in some patients, quinidine therapy off-label has been practiced successfully. This review aims to describe the characteristics of the gene, the phenotypes related to genetic mutations with the possible genotype–phenotype correlations and the treatments proposed to date, discussing the comorbidities reported in the literature.
Collective Capacity to Aspire? Aspirations and Livelihood Strategies in the Zambezi Region, Namibia
Authors: Aring Mascha , Reichardt Ole , Katjizeu Ewaldine Menjono , Luyanda Brendan , Hulke Carolin
Published: May 2021

This paper investigates rural development from a micro-level standpoint, focusing on individual and collective aspirations. We aim to deepen understanding of how a person’s socio-economic environment shapes their aspirations and simultaneously how aspirations contribute to future-oriented actions. In combining concepts of sustainable livelihoods and aspirations with a context of ‘ordinary uncertainties’ (Pine, Ordinary uncertainties: remembering the past and imagining the future at times of rupture and mobility. In: Paper presented at the conference “Rurality and Future-Making. Comparative Perspectives from Europe, the Middle East, and the Mediterranean”, 22–24 May, Cologne, Germany, 2019), we discuss the role of individual and collective aspirations in developing livelihood strategies. Drawing on qualitative data from field research in Namibia’s Zambezi region, we identify crucial factors that influence aspirations: multiple uncertainties, experiences, and role models. Access to diverse experiences and social exchange shapes future-oriented aspirations, and therefore needs to be included in rural development strategies that account for diversity within communities.
The social dilemmas of climate change and antibiotic resistance: an analytic comparison and discussion of policy implications
Authors: Harring Niklas , Krockow Eva M.
Published: May 2021

Climate change and antimicrobial resistance are two of humanity’s most imminent problems. Reducing the use of fossil fuels and antibiotics is essential for managing the threats, and theory-based policies are required to stimulate urgently needed behaviour change. This article analyses climate change and antimicrobial resistance within the context of game theory. Previous literature has identified these problems as Commons tragedies, where inherent incentive structures encourage selfish overuse of existing resources. While the game theoretical models provide a helpful conceptual basis, the present analysis suggests discrepancies between some of the theoretical assumptions and the practical realities of climate change and antimicrobial resistance. These include complex networks of decision makers, non-binary choice contexts complicated by temporal and spatial distance between choices and outcomes, and different ethical implications of resource overuse. Policy implications are discussed, highlighting the need of global agreements for coordinating local initiatives for both dilemmas. However, different target groups may be necessary to address the existence of gate keepers (e.g., medical prescribers) in antibiotic use. Additionally, while certain policies types (e.g., information policies) apply to both dilemmas, more nuanced ethical considerations mean that some economic policies (e.g., punitive policies) may be limited to managing climate change.
Compact broadband Compton spectroscopy used for intense laser-driven gamma rays
Authors: Yang Tao , Hu Guang-yue , Li Meng-ting , Lian Chang-wang , Zhang Zhen-chi , Luo Wen , Ma Yue , Zheng Jian
Published: May 2021

A compact broadband Compton spectrometer is designed to measure the continuous spectrum of gamma-ray sources driven by an intense laser. The incident gamma rays are converted into electrons in low-Z materials by Compton scattering. Produced by a pair of stepped magnets, a weaker-front–stronger-rear nonuniform magnetic field in the electron magnetic spectrometer is used to spectrally resolve the scattered electrons, leading to a broadband gamma-ray spectral coverage of 2–20 MeV in a compact volume. Flat imaging-plate detectors are placed near the focused imaging points of the magnetic spectrometer to record the dispersed electrons, thereby achieving an optimal spectral resolution of 6%–13% in the energy range of 3–20 MeV. The spectrometer is used successfully to measure the gamma-ray spectrum generated by the high-energy electron beams produced by a femtosecond-laser-driven wakefield.
A single column plasma photonic crystal (SC-PPC)
Authors: Kamboj G. K. , Yadav R. P. , Kaler R. S.
Published: May 2021

In this paper, a reconfigurable one-dimensional single column plasma photonic crystal (SC-PPC) has been investigated. The SC-PPC is a glass column containing standing plasma density patterns (SPDPs) called plasma blobs, where its density varies sinusoidally along the column axis. It appears like a collinear array of the plasma blobs which is produced by having the critical combination of input RF power and gas pressure in a column. The numbers of blobs and plasma density can be controlled by RF power and gas pressure. The value of plasma density is measured for the different numbers of plasma blobs formation by using the experimental setup. These measured data are utilized in the modeling and simulation of SC-PPC for the photonic bandgap (PBG) analysis. The simulation outcomes reveal that the SC-PPC induces PBGs that can be reconfigured with plasma density, lattice constant, and numbers of plasma blobs. This paper explicitly investigates the PBG analysis by modeling two cases, where the plasma density Ne=2.45×1016 m−3 with five plasma blobs and Ne=9×1016 m−3 with six plasma blobs are considered. The obtained outcomes verify the reconfigurable characteristics of SC-PPC.
A resonance suppression method in platform style inertial reference unit via particle swarm optimization notch filter
Authors: Zhou Z. , Li X. F. , Tuo W. X. , Zheng A. Q.
Published: May 2021

With the development of laser communication, remote sensing imaging, and other technologies, an inertial reference unit (IRU) plays an essential part in the line-of-sight (LOS) stabilization system used for acquiring, pointing, and tracking targets. The IRU provides a stable reference beam to realize accurate LOS pointing under external disturbances. Compared with the frame style IRU, the platform style IRU (PIRU) can achieve a higher bandwidth and better precision. However, mechanical resonance is introduced by a flexure hinge inevitably in the PIRU, which affects the performance of the LOS stabilization system. In this paper, an open-loop dynamic model of PIRU is established. Identification experiments are carried out with results indicating a 28.7 dB resonance peak at 27.07 Hz in the x axis and a 30.3 dB resonance peak at 26.59 Hz in the y axis. An asymmetric notch filter is used to suppress the resonance peak to achieve a higher control bandwidth. A fitness function is designed to represent the effect of resonance suppression. A particle swarm optimization algorithm is used to search for an optimal solution of the fitness function to obtain the parameters of the asymmetric notch filter. Experimental results show that the resonance peak is reduced by 97.88% and the system bandwidth reaches 159.31 Hz.
Evaluation of highly entangled states in asymmetrically coupled three NV centers by quantum simulator
Authors: Mahony Declan , Bhattacharyya Somnath
Published: May 2021

Despite numerous efforts, the coupling between randomly arranged multi-NV centers and also resonators has not been improved significantly mainly due to our limited knowledge of their free evolution time for entanglement (2τent). Here, we demonstrate very strong coupling between three NV centers by using a simulated triple electron-electron resonance experiment based on a quantum (UC) gate on an IBM quantum simulator with 2τent ∼ 12.5 μs arranged in a triangular configuration. Interestingly, through breaking, the symmetry of couplings an even lower 2τent ∼ 6.3 μs can be achieved. This simulation not only explains the luminescence spectra in recently observed three NV centers but also shows a large improvement of the entanglement in artificially created structures through a cyclic redistribution of couplings. Realistically disordered coupling configurations of NV center qubits with short time periods and high (0.89–0.99) fidelity of states clearly demonstrate the possibility of accurate quantum registers operated at room temperature.
Light coupling structures and switches for plasmonic coaxial waveguides
Authors: Mahigir Amirreza , Veronis Georgios
Published: May 2021

We introduce wavelength-scale light coupling structures and switches for plasmonic coaxial waveguides. We first consider single-slit structures optimized for a wavelength of 1550 nm and find that, when the slit is on resonance, the coupling to the plasmonic coaxial waveguide is maximized. We also observe that for optimized double- and triple-slit structures, the coupling efficiency is enhanced compared to the single-slit structure by factors of ∼3.02 and ∼4.21, respectively. We find that, in the case of double- and triple-slit structures, the surface plasmons excited at the metal–air interface enhance light coupling to the plasmonic coaxial waveguide via the slits. In addition, we investigate slit-based outcoupling structures for light extraction from the waveguide into a free space. We observe that while the far-field radiation pattern of single-slit structures is symmetric, double- and triple-slit structures have asymmetric radiation patterns. We also show that by exciting the incoupling slit structures at proper angles, we can excite only the right- or the left-propagating mode of the plasmonic coaxial waveguide. We finally design compact plasmonic switches consisting of a plasmonic coaxial waveguide side-coupled to a periodic array of two open-circuited coaxial stub resonators. Such a structure is based on a plasmonic analog of electromagnetically induced transparency and supports a slow-light mode. The space between the metallic parts is filled with an active material with a tunable refractive index. We show that the modulation depth of this structure is large enough for optical switching applications.
Temperature dependent electron–phonon coupling of Au resolved via lattice dynamics measured with sub-picosecond infrared pulses
Authors: Tomko John A. , Kumar Sushant , Sundararaman Ravishankar , Hopkins Patrick E.
Published: May 2021

The detailed understanding of energy transfer between hot electrons and lattice vibrations at non-cryogenic temperatures relies primarily upon the interpretation of ultrafast pump–probe experiments, where thermo-optical models provide insight into the relationship between optical response and temperature of the respective sub-systems; in one of the more studied materials, gold, the Drude model provides this relationship. In this work, we investigate the role of intra- and interband contributions applied to transient optical responses in ultrafast pump–probe experiments using both experiments and first-principle calculations, with probe wavelengths spanning from UV wavelengths into the infrared. We find that during conditions of electron–phonon equilibrium, the Drude model is not applicable to visible wavelengths due to interband transitions. Instead, at probe wavelengths far from these interband transitions (e.g., infrared wavelengths), the optical response is linearly proportional to the temperature of the phonon sub-system and is no longer obfuscated by Fermi-smearing, thus greatly simplifying the extraction of the electron–phonon coupling factor. Our intraband-probe measurements on the electron–phonon coupling factor of Au are in excellent agreement with analytical models and ab initio calculations; we observe a constant electron–phonon coupling factor up to electron temperatures of at least ∼2000 K.
Spectroscopic quantification of the nanoparticle production efficiency of copper wire explosion
Authors: Égerházi L. , Kovács B. , Szörényi T.
Published: May 2021

Wire explosion is a technically straightforward green method for nanoparticle production; however, the determination of polydisperse and multimodal particle size distribution and thereby the assessment of the efficiency of the process pose serious challenges. Fitting extinction spectra derived from the Mie theory to the measured extinction spectra of colloidal solutions produced by the explosion of copper wires of 70 μm diameter and 20 mm length by discharging a capacitor of 435 nF charged to voltages ranging from 4 to 12 kV in an aqueous environment allows for determining the size distribution of the particles in the 10–300 nm diameter range and provides information on their oxidation state as well. In underwater wire explosion of copper, the vast majority of the nanoparticles transforms into copper oxides already during the process. The size distribution remains bimodal throughout the whole charging voltage range investigated. The nanoparticles follow a lognormal size distribution with a mode at 30 nm, while the fine particle population extending from 100 to 300 nm in diameter is dominated by rather normally distributed copper droplets with modes at 160–170 nm. The energy injected into the wire controls the individual concentration of both the fine and nanoparticles with the modes and ranges remaining hardly affected. The number concentration of the nanoparticles increases monotonically with the energy, spanning more than one order of magnitude. The throughput assessed by the total mass of the nanoparticles divided by the total mass of all species identified in the sol within the 0–300 nm diameter range increases monotonically from 1% at 4 kV up to 41% at 12 kV, revealing that wire explosion can be optimized for efficient nanoparticle production.
Hyperscroll dynamics: Vortices in four-dimensional networks
Authors: Zanotto Franco M. , Steinbock Oliver
Published: May 2021

We investigate a network of excitable nodes diffusively coupled to their neighbors along four orthogonal directions. This regular network effectively forms a four-dimensional reaction–diffusion system and has rotating wave solutions. We analyze some of the general features of these hyperscroll waves, which rotate around surfaces such as planes, spheres, or tori. The surfaces evolve according to local curvatures and a system-specific surface tension. They have associated local phases and phase gradients tend to decrease over time. We also discuss the robustness of these network states against the removal of random node connections and report an example of hyperscroll turbulence.
A domain wall-magnetic tunnel junction artificial synapse with notched geometry for accurate and efficient training of deep neural networks
Authors: Liu Samuel , Xiao T. Patrick , Cui Can , Incorvia Jean Anne C. , Bennett Christopher H. , Marinella Matthew J.
Published: May 2021

Inspired by the parallelism and efficiency of the brain, several candidates for artificial synapse devices have been developed for neuromorphic computing, yet a nonlinear and asymmetric synaptic response curve precludes their use for backpropagation, the foundation of modern supervised learning. Spintronic devices—which benefit from high endurance, low power consumption, low latency, and CMOS compatibility—are a promising technology for memory, and domain-wall magnetic tunnel junction (DW-MTJ) devices have been shown to implement synaptic functions such as long-term potentiation and spike-timing dependent plasticity. In this work, we propose a notched DW-MTJ synapse as a candidate for supervised learning. Using micromagnetic simulations at room temperature, we show that notched synapses ensure the non-volatility of the synaptic weight and allow for highly linear, symmetric, and reproducible weight updates using either spin transfer torque (STT) or spin–orbit torque (SOT) mechanisms of DW propagation. We use lookup tables constructed from micromagnetics simulations to model the training of neural networks built with DW-MTJ synapses on both the MNIST and Fashion-MNIST image classification tasks. Accounting for thermal noise and realistic process variations, the DW-MTJ devices achieve classification accuracy close to ideal floating-point updates using both STT and SOT devices at room temperature and at 400 K. Our work establishes the basis for a magnetic artificial synapse that can eventually lead to hardware neural networks with fully spintronic matrix operations implementing machine learning.
Propulsion kinematics of achiral microswimmers in viscous fluids
Authors: Benhal Prateek , Quashie David , Cheang U Kei , Ali Jamel
Published: May 2021

Here we investigate the dynamic behavior of self-assembling achiral swimmers in viscous media. The response of magnetically actuated swimmers of two differing geometries is explored under various uniform rotational field frequencies and amplitudes. Kinematic characteristics obtained from tracked swimming motion, including speed, precession angle (wobbling angle), and re-orientation time (turning rate), are determined and reveal nonlinear relationships between the dynamic response of the achiral swimmers and fluid viscosity, which induces drag forces that reduce the speed of propulsion and turning rates. We also find distinct regimes of swimmer motion that are dependent on both fluid viscosity and swimmer geometry. Similar viscosity and geometric dependence is observed for turning rates of swimmers when undergoing rapid changes in field orientation. The characteristic results obtained for microswimmer motion in viscous fluids will contribute to the development of control strategies for propelling other simple swimmers with two or more planes of symmetry. Characterized propulsion kinematics will aid in the optimization of swimmer designs and actuation approaches, critical for future low Reynolds number applications.
Interfacial instability and transition of jetting and dripping modes in a co-flow focusing process
Authors: Mu Kai , Qiao Ran , Si Ting , Cheng Xueqin , Ding Hang
Published: May 2021

The breakup dynamics of coaxial liquid interfaces into compound droplets in a co-flow focusing process is studied systematically. In experiments, the jetting and dripping modes downstream the focusing orifice are identified within the parametric regime where a coaxial liquid cone can be established steadily, and the phase diagram is plotted under different flow rates of inner, outer, and driving liquids. The force balance for the jet interface is analyzed numerically to explore the critical conditions for the jetting-dripping transition. It is found that the instability of the inner interface is much easier to trigger the modes transition, and the transition criterion is decided by the balance of inertia force, shear stress, and interfacial tension at the local inner jet. The linear spatiotemporal instability analysis is further carried out to study the convective and absolute instabilities of the coaxial jets. The effects of main process parameters on jet instability are accessed, and the boundary between the absolute/convective instabilities is further compared with the experimental and numerical results, which achieves good agreement. Finally, the energy budget analysis of the instability of coaxial liquid jets is performed to provide more understanding of physical mechanisms for the mode transition.
Mechanistic basis of transport in unconfined swirling flows
Authors: Chakraborty Priyam , Roy Arnab , Chakraborty Suman
Published: May 2021

Swirling flows constitute several physical systems, such as the lift-enhancers on the flapping wings in animal flight and mechanical blood pumps. Swirls are stable due to inhibited mixing. However, the modulation of mixing in the swirl due to ambience is not known. Here, we study the transport phenomena in a non-reacting unconfined constant-density Newtonian axisymmetric swirling flow using a two-dimensional model. The objective is to investigate how diffusive amplification varies with radial distance from the geometric center of the swirl. The present work generates feedback on the extent of mixing and has implications in an integrative design of physical systems.
Introduction
Authors: Elliott Barry
Published: May 2021

To understand better how light is used in modern optical communications, it helps to first understand the history of light and how people have used it throughout history to observe, send, and receive information. This chapter discusses early uses of light, dating back more than three centuries, as both a navigation tool and a topic of research on its basic nature. It continues with further developments in using light as a communication medium, up to the invention of optical fiber in the late 20th century. This introductory chapter provides context for the remainder of the book, which discusses both the scientific fundamentals that allow optical communication to work and the modern advances used in today's high-speed networks.
Polarization
Authors: Elliott Barry
Published: May 2021

To understand how light propagates through a medium we need to know the basics of electromagnetic theory, polarization, reflection, and diffraction. In this chapter we shall address the principles of polarization. We shall consider the nature of polarization and how linear, circular and elliptical polarization states are just different aspects of the same rotation of the electric field as is best demonstrated by the Poincare sphere. Unpolarized light can be polarized by subjecting it to various physical effects which we shall consider. We then move on to describe how polarized light can be created. Polarization can be caused by a transmissive polarizing device, by reflection, by refraction or by scattering. The production of polarized light can result in linear, circular or elliptical polarization and also depends upon the nature of the light approaching the cause of polarization, e.g. randomly (or unpolarized) light, partially polarized and linear, circular or elliptical states of polarization. We also have the Faraday Effect where an electromagnetic field impinging upon an electromagnetic wave can cause polarization of the wave. Using, manipulating, and understanding polarization leads to many practical uses in the fields of biology, medicine, geology, astronomy and many other physical sciences including communications.
The Laws of Reflection, Refraction, and Diffraction
Authors: Elliott Barry
Published: May 2021

To understand how light propagates through a medium we need to know the basics of electromagnetic theory, polarization, reflection, diffraction and diffraction. In this chapter we shall address the principles of reflection, refraction and diffraction. Arguably the most complex and important element of this set of phenomena is refraction, the apparent bending of the path of a ray of light when it passes from one medium to another. This happens because light slows down when it travels through a transparent medium. We have to come to learn that the speed of light is a constant, just under 300,000 km per second. But when light travels through a medium which is not totally opaque and has some density above a vacuum there is an interaction between the light and the physical medium which has the effect of slowing the light down. Electromagnetic waves, including light and radio waves, can be refracted through the atmosphere and refraction is at the heart of how optical fibres work. The mathematics of Snell, Huygens and Fermat can explain and predict the laws of refraction, but a more complete understanding of why it happens can be taken from Maxwell)s equations and these will be introduced in this chapter.
Nanoparticle-enabled innate immune stimulation activates endogenous tumor-infiltrating T cells with broad antigen specificities
Authors: Yin Qian , Yu Wong , Grzeskowiak Caitlin L. , Li Jing , Huang Huang , Guo Jing , Chen Liang , Wang Feng , Zhao Fan , von Boehmer Lotta , Metzner Thomas J. , Leppert John T. , Chien Yueh-hsiu , Kuo Calvin J. , Davis Mark M.
Published: May 2021

Significance

Tumors are often infiltrated by T lymphocytes recognizing either self- or mutated antigens but are generally inactive. Self-specific CD8+T cells are particular characteristics of tumor types with lower tumor mutation burden and poorer outcomes. Unlike foreign-specific T cells, they have been curiously resistant to stimulation with cognate antigens. We developed an innate immunity-stimulating nanoparticle to activate tumor-infiltrating CD8+T cells recognizing both self- and neoantigens in a potent yet safe manner. This resulted in effective tumor growth inhibition or elimination in two murine tumor models and the activation of endogenous T cells in patient-derived tumor organoids across three cancer types. This strategy represents a promising pathway for broadly effective cancer immunotherapy.
Dynamic population stage structure due to juvenile–adult asymmetry stabilizes complex ecological communities
Authors: de Roos André M.
Published: May 2021

Significance

Using food web models that account for juvenile and adult individuals of species, I show that commonly observed differences between juveniles and adults in foraging capacity and predation risk result in larger, more complex communities than predicted by models without stage structure. Based on their species interaction networks these complex and diverse communities would be expected to be unstable, but these destabilizing effects of species interactions are overruled by stabilizing changes in juvenile–adult stage structure. Differences between juvenile and adult individuals hence offer a natural resolution to the diversity–stability enigma of ecological communities.
Random heterogeneity outperforms design in network synchronization
Authors: Zhang Yuanzhao , Ocampo-Espindola Jorge L. , Kiss István Z. , Motter Adilson E.
Published: May 2021

Significance

Synchronization among interacting entities is a process that underlies the function of numerous systems, including circadian clocks and laser arrays. It is generally believed that homogeneity among the entities is beneficial for synchronization. This work shows theoretically, numerically, and experimentally that the opposite is not only possible but also common in systems with interaction delays. In such systems, heterogeneity among the entities is shown to promote synchronization, even when the heterogeneity is completely random. This finding advances our understanding of the interplay between order and disorder in the collective behavior of complex systems. We suggest that the phenomenon can be observed for diverse coupling schemes and has implications for real-world systems, where heterogeneity and delays are common and often unavoidable.
Elementary mechanisms of calmodulin regulation of Na
V
1.5 producing divergent arrhythmogenic phenotypes
Authors: Kang Po Wei , Chakouri Nourdine , Diaz Johanna , Tomaselli Gordon F. , Yue David T. , Ben-Johny Manu
Published: May 2021

Significance

Calmodulin (CaM) regulation of cardiac Na
V
channels is vital for cardiac physiology and pathophysiology. Channelopathic mutations in Na
V
1.5 that disrupt CaM binding trigger two mechanistically divergent arrhythmia syndromes. Specifically, long QT syndrome 3 results from a gain-of-channel function, while Brugada syndrome stems from a loss-of-channel function. Yet, mechanisms that elicit seemingly paradoxical changes in channel function are unknown. Using single-channel analysis, we demonstrate that the disruption of CaM binding to Na
V
1.5 diminishes channel activity and enhances the propensity for persistent Na
+
current, all resulting from a switch in the Na
V
inactivation mechanism. These findings reveal insights into the mechanism of CaM regulation of Na
V
channels as well as inform upon alterations in channel function that trigger life-threatening arrhythmias.
Impatiens parviflora (small balsam).
Authors: Tanner Rob
Published: May 2021

I. parviflora is an exceptionally successful invader of many European countries. Its spread has been rapid, it is abundant in many parts of its exotic range and is one of few plants to successfully invade undisturbed forest vegetation. It is consequently regarded as undesirable by some, though there is little evidence of negative economic, social or environmental impacts. Further spread in central Europe is not likely as the species is already very abundant. In North America, on the other hand, it is still very localized. Even without clear evidence for impacts, a further spread there should not be encouraged by deliberate or careless transport of the species.
Paspalum distichum (knotgrass).
Authors: Parker Chris
Published: May 2021

P. distichum is a fast-growing rhizomatous grass of wet areas. It has become a major weed of rice and many other crops, as well as occurring in uncropped wetlands in both its native and introduced regions. Its introduction to Europe, Asia and the Pacific is not well documented but apparently occurred many years ago. New records are reported in e.g. Indonesia, Spain and Croatia, suggesting that it continues to spread in countries to which it has been introduced.
CAMSAPs organize an acentrosomal microtubule network from basal varicosities in radial glial cells
Authors: Coquand Laure , Victoria Guiliana Soraya , Tata Alice , Carpentieri Jacopo Amerigo , Brault Jean-Baptiste , Guimiot Fabien , Fraisier Vincent , Baffet Alexandre D.
Published: May 2021

Neurons of the neocortex are generated by stem cells called radial glial cells. These polarized cells extend a short apical process toward the ventricular surface and a long basal fiber that acts as a scaffold for neuronal migration. How the microtubule cytoskeleton is organized in these cells to support long-range transport is unknown. Using subcellular live imaging within brain tissue, we show that microtubules in the apical process uniformly emanate for the pericentrosomal region, while microtubules in the basal fiber display a mixed polarity, reminiscent of the mammalian dendrite. We identify acentrosomal microtubule organizing centers localized in varicosities of the basal fiber. CAMSAP family members accumulate in these varicosities, where they control microtubule growth. Double knockdown of CAMSAP1 and 2 leads to a destabilization of the entire basal process. Finally, using live imaging of human fetal cortex, we reveal that this organization is conserved in basal radial glial cells, a related progenitor cell population associated with human brain size expansion.
Immune cells—A curse and a blessing!
Authors: Mirakaj Valbona
Published: May 2021

Innate immune cells are crucial in the development and regulation of cardiovascular disease. In this issue, two groups, Davis et al. (2021. J. Exp. Med.https://doi.org/10.1084/jem.20201839) and Li et al. (2021. J. Exp. Med.https://doi.org/10.1084/jem.20210008) describe the impact of the innate immune system on the development of cardiovascular disease.
Structural Humility
Authors: Davis Cruz Austin
Published: May 2021

In this article I discuss various humility theses about individuals and intrinsic properties as discussed by authors such as David Lewis. I argue that we should accept a similar humility thesis about the world’s space-time structure regardless of which metaphysics of space-time we accept. I argue this undercuts some important motivations opting in for an ontic structural realist metaphysic.
Surface chemistry-dependent antiviral activity of silver nanoparticles
Authors: Sinclair Terica R , van den Hengel Sanne K , Raza Brahzil G , Rutjes Saskia A , de Roda Husman Ana Maria , Peijnenburg Willie J G M , Roesink H (Erik) D W , de Vos Wiebe M
Published: May 2021

The toxicity towards viruses of silver nanoparticles (AgNPs) has been reported to be dependent on several factors such as particle concentration, size, and shape. Although these factors may indeed contribute to the toxicity of AgNPs, the results presented in this work demonstrate that surface chemistry and especially surface charge is a crucial factor governing their antiviral activity. Here, this work investigated the influence of capping agents representing various surface charges ranging from negative to positive. These AgNPs were capped with citrate, polyethylene glycol (PEG), polyvinylpyrrolidone (PVP) mercaptoacetic acid (MAA) and (branched polyethyleneimine (BPEI). We show that AgNPs exhibited surface charge-dependent toxicity towards MS2 bacteriophages. Among the capping agents under investigation, BPEI capped AgNPs (Ag/BPEI) exhibited the highest reduction of MS2 resulting in ≥6 log10-units reductions, followed by 4–5 log10-units reductions with PVP and PEG capping’s and 3–4 log10-units with MAA and citrate cappings. Bare nanoparticles reported a mere 1–2 log10-units reduction. Electrostatic interaction between the positively charged BPEI-coating and the negatively charged virus surface played a significant role in bringing the MS2 closer to toxic silver ions (Ag+). Further results obtained from TEM showed that Ag/BPEI nanoparticles could directly damage the structure of the MS2 bacteriophages. AgNPs and cationic capping agents’ observed synergy can lead to much lower and much more efficient dosing of AgNPs for antiviral applications.
Entropy minimization on magnetized Boussinesq couple stress fluid with non-uniform heat generation
Authors: K Gangadhar , D Naga Bhargavi , M Venkata Subba Rao , Chamkha Ali J
Published: May 2021

This article aims to investigate the generation of entropy for the magnetized coupled stress fluid passed through a permeable stretching cylinder that creates the condition of convective heat transfer. Additionally, in the uneven heat source in the flow field, we also analyzed our research. The properties of heat transfer taking into account in the perspective of thermal radiation. The main nonlinear partial differential equations (NPDE) become ordinary nonlinear differential equations by adopting the corresponding dimensionless variables. The recognized repeated shooting technique combined with the fourth-order standard Runge-Kutta integration solution to evaluate the resulting nonlinear ODE numerically. The velocity, temperature profile, streamline, number of local entropy generations, Bejan number, local friction coefficient, and Nusselt number effects of the new flow parameters are explained by graphs and tables. The flow system’s physical properties and the correlation between the parameters were clarified by using statistical methods. The results show that the Bejan number is reduced due to the magnetic source. Generation of entropy promotes the growth of the magnetic field and the Brinkman number, but the coupling stress aspect shows a double effect. The coupled stress parameter reduces the number of Nusselt by a fraction of 4.46%, while in the attendance of a magnetic field, the radiant heat transfer rate increases at a rate of 2.65%. In the attendance of a magnetic field, skin friction reduces the coupling stress factor by a rate of 24.67%. Besides, the current outcomes have been verified by previously published studies and are very acceptable. For the stretched cylinder, which has a curvature parameter of γ = 1.0, and for the flat, stretched surface, γ = 0.0, the thickness of the momentum and the thermal boundary layer are greater.
Tunable optical isolator using Graphene-photonic crystal-based hybrid system
Authors: Zarei Mohsen , Nazari Fakhroddin , Moravvej-Farshi Mohammad Kazem
Published: May 2021

In this article, an optical isolator is designed and simulated based on a hybrid configuration of the photonic crystal (PhC) and graphene. The PhC membrane is a hexagonal lattice of air holes arranged in a nonlinear silicon substrate. To provide a nonreciprocal transmission (optical isolator), breaking the symmetry of the light propagation path (the forth and back routes) is an essential condition. Here, the asymmetrical round trip of the light propagation and the Kerr-nonlinear effect are employed to obtain asymmetric propagation. The isolator structure includes a PhC waveguide that asymmetrically side-coupled to a specific embedded cavity. Then, to attain a tunable asymmetric transmission, a Nano-layer of graphene is located on the top of the mentioned PhC configuration. By altering the chemical potential of graphene one can control the isolation rate, frequency, and bandwidth of offered structure and thus possess a tunable optical isolator. The simulation results show that a 0.5 nm frequency shift can attain by the graphene chemical potential alterations from 0.45 eV to 0.65 eV in which it is suitable for Dense Wavelength Division Multiplexing (DWDM) communication and integrated optical circuits. Furthermore, as another advantage, a high forward normalized transmission (0.6) has resulted in a large average isolation rate of 32.5 dB due to low losses of the proposed structure.
Absence of superconductivity in the repulsive Hubbard model on a square lattice in the regime of strong coupling
Authors: Sherman A
Published: May 2021

The possibility of the superconducting transition in the repulsive Hubbard model on a square lattice is studied using the ladder approximation of the strong coupling diagram technique. The t–U and t–t′–t″–U models are considered in the regime of strong correlations, for the on-site Coulomb repulsion U = 8t, in the range of temperatures 0.02t ≲ T ≲ 0.3t. To avoid the influence of the phase separation and size effects the calculations are performed in an infinite crystal, in the part of the phase diagram without inhomogeneities, for the electron concentration

n

¯

=
0.92

. Solutions of the Eliashberg equation for singlet and triplet pairing, which are transformed according to one-dimensional representations of the lattice point group D
4, are considered. For both models and all considered symmetries, eigenvalues of the Eliashberg equation are less than unity and demonstrate no upward trend with decreasing temperature. This result points to the absence of superconductivity in the Hubbard model in the strong-coupling regime. We discuss the reason for the small eigenvalue of the Eliashberg equation in the case of the singlet

d

x

2

−

y

2

pairing.
Galaxy shape statistics in the effective field theory
Authors: Vlah Zvonimir , Chisari Nora Elisa , Schmidt Fabian
Published: May 2021

Intrinsic galaxy alignments yield an important contribution to the observed statistics of galaxy shapes. The general bias expansion for galaxy sizes and shapes in three dimensions has been recently described by Vlah, Chisari & Schmidt using the general perturbative effective field theory (EFT) framework, in analogy to the clustering of galaxies. In this work, we present a formalism that uses the properties of spherical tensors to project galaxy shapes onto the observed sky in the flat-sky approximation, and compute the two-point functions at next-to-leading order as well as the leading-order three-point functions of galaxy shapes and number counts. The resulting expressions are given in forms that are convenient for efficient numerical implementation. For a source redshift distribution typical of Stage IV surveys, we find that nonlinear intrinsic alignment contributions to galaxy shape correlations become relevant at angular wavenumbers l ≳ 100.
The separatrix operational space of ASDEX Upgrade due to interchange-drift-Alfvén turbulence
Authors: Eich T. , Manz P. , the ASDEX Upgrade team
Published: May 2021

The efficient operation of a tokamak is limited by several constraints, such as the transition to high confinement or the density limits occurring in both confinement regimes. These particular boundaries of operation are derived in terms of a combination of dimensionless parameters describing interchange-drift-Alfvén turbulence without any free adjustable parameter. The derived boundaries describe the operational space at the separatrix of the ASDEX Upgrade tokamak, which is presented in terms of an electron density and temperature existence diagram. The derived density limits are compared against Greenwald scaling. The power threshold and role of ion heat flux for the transition to high confinement are discussed.
R&D tax credits can be a significant source of taxpayer support for fossil fuel innovation
Authors: McDowall Will
Published: May 2021

The urgent need to accelerate the transition towards low-carbon energy is well understood. Government support for energy innovation has been an increasing focus of both policy and academic attention in recent years. The debate has focused on direct spending by governments on research and development (R&D). However, governments also support R&D indirectly, through tax credits. This source of government support has been overlooked in the academic and policy debate on energy innovation, in part because publicly available data on R&D tax credit expenditures typically do not enable the identification of spending specific to energy. This article provides the first published data on R&D tax credits in the energy sector, drawing on administrative data from Australia, Canada, Norway and the UK. This data shows that indirect support through tax credits can be a large source of support for innovation in fossil fuel extraction companies, though this differs by country. As a result, publicly available data on direct R&D spending by government can significantly understate government support for innovation in fossil fuel extraction. The article also presents patent data to show, for the UK and for Norway, that less than 5% of R&D activity in fossil fuel extraction firms is devoted to low-carbon technologies. The article concludes with the recommendation that governments should consider removing tax credit support for R&D activities that facilitate the extraction of fossil fuels.
Differences in seasons and rice varieties provide opportunities for improving nitrogen use efficiency and management in irrigated rice in Kenya
Authors: Gweyi-Onyango Joseph P , Ntinyari Winnie , OgollaEgesa Andrew , Mose Richard , Njinju Symon , Giweta Mekonnen , Masso Cargele
Published: May 2021

Apart from nitrogen (N) rates, N use efficiency (NUE) (yield N/total input N) is affected by seasons, crop developmental stages, and varieties. Knowledge of how these factors affect NUE in rice production in Kenya is limited. Therefore, field experiments were conducted with ‘low rates’ of N (simulating farmers’ practices) of 0, 26, 52 and 78 kg N ha−1with five varieties (MWUR1, MWUR4, IRAT109, NERICA4 and NERICA10) and higher rates of N (125, 175, and 225 kg N ha−1) simulating researchers’ doses with two lowland varieties (Basmati 370 and BW 196) and IR 72. Another experiment on NUE responses to sites, N rates and dose (split or full dose) was undertaken with the IR97 variety. With the ‘low rate’, yields increased with incremental N rates up to 52 Kg N ha−1and declined (during cold periods, for some varieties). In this scenario, the N agronomic efficiencies (AEN) declined with increasing N but depended on sites and seasons. However, most AENvalues were above 100, implying nutrient mining. In most cases (except at the Mwea site), the N utilization efficiency (NUtE) ranged from 16 to 22kg kg−1and were not significantly affected by sources and methods of N application. In all cases, an increase in N elicited declining trends in NUtE. Moreover, N uptake efficiency ranged between 22 and 90kg kg−1without significant variation among varieties. For the ‘high N rates’, high biomass yield resulted in higher grain yields in BW 196 and IR 72 but yield declined beyond 75 kg ha−1N rates due to poor grain filling, particularly when a cold period coincided with booting and grain filling. We conclude that N rates, doses and rice varieties are key determinants of AENand NUtE in contrasting rice growing seasons in Kenya. Cropping seasons and rice varieties are therefore potential key determinants of sustainable rice productivity and improved NUE in rice-based systems in the studied regions of Kenya.