bluuebunny/crossref_metadata_2025 huggingface dataset:
Detection of Colistin Resistance in Carbapenem Resistant Enterobacteriaceae by Reference Broth Microdilution and Comparative Evaluation of Three Other Methods
Authors: Kar Punyatoya , Behera Bijayini , Mohanty Srujana , Jena Jayanti , Mahapatra Ashoka
Published: July 2021

Objective Challenges in susceptibility testing of colistin along with increase in the prevalence of colistin-resistant carbapenemase-producing Enterobacteriaceae (CRE) pathogens needs addressal. Evaluation of user-friendly methods is necessary as an alternative to broth microdilution (BMD), the reference susceptibility testing method, for routine implementation in diagnostic clinical microbiology laboratories. Genotypic detection of the plasmid-mediated colistin resistance is also needed for infection control purposes.

Materials and Methods Colistin susceptibility of 200 nonduplicate clinical CRE isolates from December 2017 to June 2019 was determined by BMD, agar dilution (AD), E test, and rapid polymyxin NP test and interpreted as per the European Committee on Antimicrobial Susceptibility Testing. The results of AD, E test, and NP test were compared with that of BMD, considering minimal inhibitory concentration (MIC) ≤ 2 µg/mL as susceptible and > 2 µg/mL as resistant. Presence of any plasmid-mediated colistin resistance (mcr-1 and 2) was evaluated in 27 colistin-resistant CRE isolates by polymerase chain reaction.

Statistical Analysis Performance of different phenotypic methods was analyzed by comparing MIC results of AD and E test with that of reference BMD method. Agreement between BMD and the other two methods was expressed in terms of categorical agreement and essential agreement. Errors were expressed as very major error (VME: false-susceptible) and major error (ME: false-resistance) by AD/E test. VME and ME of 3% disagreement were considered unacceptable.

Results Colistin resistance was found in 27 (13.5%) isolates by BMD method. The VME rates of both AD (11%) and E test (37%) could not meet the Clinical and Laboratory Standards Institute recommendation (< 3% VME rate is acceptable) as alternative tests to the reference BMD. Colistin NP test showed sensitivity and specificity of 85% and 98%, respectively. The percentage discordant result in NP test was highest in Enterobacter spp. (17%). None of the 27 colistin resistant isolates showed presence of mcr-1 and mcr-2 genes.

Conclusion High VME rate in AD and E tests precludes their use as alternatives to BMD for colistin susceptibility testing. NP test with moderate sensitivity but excellent specificity can be a good alternative for testing colistin susceptibility in CRE isolates, except in Enterobacter spp. Absence of mcr-1 and mcr-2 gene necessitates the exploration of other mechanisms of colistin resistance.
Assessment of Iodine Deficiency among School-Going Children of Age Group 6 to 12 Years in Kachchh District, Gujarat State: Cross-Sectional Hospital-Based Study
Authors: Sharma Dinesh P. , Maheshwari Amitkumar , Chakrabarti Chandan , Patel Darshan J.
Published: July 2021

Aim Iodine deficiency disorder (IDD) is the cause of preventable brain damage, mental retardation, and stunted growth and development in children. This study aimed to detect the prevalence of IDD in Kachchh district, Gujarat, by testing urinary iodine excretion levels and iodine intake of salts in school-going children.

Methods A cross-sectional study was conducted and the level of iodine deficiency was assessed in 223 school children of both sexes, aged 6 to 12 years from four talukas, that is, subdivisions, of the Kachchh district by estimating urinary iodine using Sandell–Kolthoff reaction along with iodine content in edible salt samples by MBI kit (STK-Spot testing kit, MBI Kits International, Chennai, TN, India).

Results The median urinary iodine level was found to be 194 μg/L, indicating no biochemical iodine deficiency in the region. In the study areas, 1% of the population showed a level of urinary iodine excretion < 50 μg/L. About 83% salt samples had iodine level more than 15 ppm and the iodine content in salt samples less than 15 ppm was only about 17%, indicating the salt samples at households contain iodine in adequate level.

Conclusion There is a need of periodic surveys to assess the change in magnitude of IDD with respect to impact of iodized salt intervention.

Furthermore, to strengthen National Iodine Deficiency Disorders Control Program, factors should be identified. There is also a need to prevent and reimpose the ban on the sale of noniodized salts in Gujarat.
Understanding the timing of Chinese border incursions into India
Authors: Greene Kevin T. , Tornquist Caroline , Fokkink Robbert , Lindelauf Roy , Subrahmanian V. S.
Published: July 2021

Since the 1960s China and India have engaged in a dispute about the demarcation of their shared border. This territorial dispute led to a brief war in 1962, and recurring flare-ups over the following decades, including during the summer of 2020. The potential for further escalation of this dispute poses significant risks to Indian and Chinese civilians, US foreign policy objectives, and the stability of the international economic system. Despite the importance of this dispute, there have been relatively few attempts to understand the correlates of Chinese incursions. This paper addresses this important question by leveraging past work on the study of conflicts between states to derive a set of testable explanations about the impact of China–India relations, internal political affairs, international political issues, and domestic economic factors on the likelihood of incursions. The study uses 15 years of original data on monthly Chinese incursions into India along with a monthly dataset containing 18 independent variables, to develop a detailed statistical understanding of the factors that trigger Chinese incursions across the Indian border with a lead time between 1 and 6 months. The quantitative study finds that Chinese incursions are more likely when Chinese leadership is early in their tenure, but more likely when Indian leadership is in the later stages of their tenure. The results also show that closer cooperation between India and the US may trigger additional Chinese incursions into India. Finally, lower consumer confidence in the Chinese economy is consistently related to an increased likelihood of incursions. These findings have implications for the maintenance of peace and India’s national security policies. Periods of Chinese uncertainty, particularly when their economy exhibits weakness and when Chinese leaders are in the early stages of their tenure are more likely to experience incursions. Further, the strengthening of the US–Indian alliance, as well as increased conflict between India and Pakistan, create the potential for an elevated risk of incursions. During these periods India should likely be on higher alert, while India and Indian allies should signal the importance of diplomatic solutions for the dispute.
Concentration-dependent influence of silver nanoparticles on amyloid fibrillation kinetics of hen egg-white lysozyme
Authors: Fan Wei , Chen Xiao-dong , Liu Li-ming , Chen Ning , Zhou Xiao-guo , Zhang Zhi-hong , Liu Shi-lin
Published: July 2021

Understanding the influence of nanoparticles on the formation of protein amyloid fibrillation is crucial to extend their application in related biological diagnosis and nanomedicines. In this work, Raman spectroscopy was used to probe the amyloid fibrillation of hen egg-white lysozyme in the presence of silver nanoparticles (Ag-NPs) at different concentrations, combined with atomic force microscopy and thioflavin T (ThT) fluorescence assays. Four representative Raman indicators were utilized to monitor transformation of the protein tertiary and secondary structures at the molecular level: the Trp doublet bands at 1340 and 1360 cm−1, the disulfide stretching vibrational peak at 507 cm−1, the N-Cα-C stretching vibration at 933 cm−1, and the amide I band. All experimental results confirmed the concentration-dependent influence of AgNPs on the hen egg-white lysozyme amyloid fibrillation kinetics. In the presence of AgNPs at low concentration (17 µg/mL), electrostatic interaction of the nanoparticles stabilizes disulfide bonds, and protects the Trp residues from exposure to hydrophilic environment, thus leading to formation of amorphous aggregates rather than fibrils. However, with the action of AgNPs at high concentration (1700 µg/mL), the native disulfide bonds of hen egg-white lysozyme are broken to form Ag-S bonds owing to the competition of electrostatic interaction from a great deal of nanoparticles. As for providing functional surfaces for protein to interact with, AgNPs play a bridge role in direct transformation from α-helices to organized β-sheets. The present investigation sheds light on the controversial effects of AgNPs on the kinetics of hen egg-white lysozyme amyloid fibrillation.
Fabrication for improved photocatalytic H2 production using γ-ray irradiation: Yolk-shell and hollow structures derived from MIL-125
Authors: Tai Chen , Liu Hua-rong , Hu Yuan
Published: July 2021

The yolk-shell MIL-125/TiO2/ Pt/CdS and hollow TiO2/Pt/CdS visible-light catalysts were successfully synthesized from MIL-125 by γ-ray irradiation. During the reduction process by γ-ray irradiation, metal organic frameworks are partially or completely hydrolyzed to TiO2 nanosheets, forming the unique yolk-shell or hollow structure. The hydrogen production rate is 2.9835 mmol·g−1·h−1 for yolk-shell structures and 1.9342 mmol·g−1·h−1 for hollow structures under visible-light illumination, which is 7.9 and 5.1 times higher than that of CdS, respectively. The excellent properties of these photocatalysts may be attributed to the effective absorption and utilization of the light, the porous yolk-shell or hollow structure derived from MIL-125 to facilitate mass transfer, and close contact among CdS nanoparticles, TiO2 nanosheets and Pt nanoparticles to improve the separation of electron-hole pairs. This research can provide a simple and new method for the construction of high efficiency photocatalysts derived from MOFs using the γ-ray irradiation.
CO2 reduction on metal-doped SnO2(110) surface catalysts: Manipulating the product by changing the ratio of Sn:O
Authors: Cui Lei , Zhang DaDi , Kong Yuan , Zheng Xiao
Published: July 2021

The electrocatalytic carbon dioxide reduction reaction (CO2RR) producing HCOOH and CO is one of the most promising approaches for storing renewable electricity as chemical energy in fuels. SnO2 is a good catalyst for CO2-to-HCOOH or CO2-to-CO conversion, with different crystal planes participating the catalytic process. Among them, (110) surface SnO2 is very stable and easy to synthesisze. By changing the ratio of Sn:O for SnO2(110), we have two typical SnO2 thin films: fully oxidized (stoichiometric) and partially reduced. In this work, we are concerned with different metals (Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Os, Ir, Pt, and Au)-doped SnO2(110) with different activity and selectivity for CO2RR. All these changes are manipulated by adjusting the ratio of Sn:O in (110) surface. The results show that stochiometric and reduced Cu/Ag doped SnO2(110) have different selectivity for CO2RR. More specifically, stochiometric Cu/Ag-doped SnO2(110) tends to generate CO(g). Meanwhile, the reduced surface tends to generate HCOOH(g). Moreover, we also considered the competitive hydrogen evolution reaction (HER). The catalysts SnO2(110) doped by Ru, Rh, Pd, Os, Ir, and Pt have high activity for HER, and others are good catalysts for CO2RR.
Obtaining simultaneously high crystallinity and sub-bandgap absorption in femtosecond laser hyperdoped black silicon using ion beam etching
Authors: Paulus Simon , Mc Kearney Patrick , Völklein Friedemann , Kontermann Stefan
Published: July 2021

Femtosecond laser sulfur hyperdoped silicon (fs-hSi) is capable of absorbing photons in the infrared spectral range while simultaneously exhibiting negligible reflection. However, laser processing creates detrimental amorphous and polycrystalline silicon surface layers impairing electronic properties, especially reducing minority charge carrier lifetimes. This paper demonstrates how to selectively remove these disadvantageous layers by ion beam etching, while crystalline IR-absorbing silicon underneath is left. The increase in silicon crystallinity is quantified by laterally probing the fs-hSi samples with Raman spectroscopy.
Numerical investigation of natural transitions of bow boundary layers over underwater axisymmetric bodies
Authors: Liu Jingcheng , Chu Xuesen , Zhang Yongming
Published: July 2021

The natural transitions of bow boundary layers over underwater axisymmetric bodies are investigated using numerical methods. The laminar flow fields over the underwater axisymmetric bodies are first calculated, and then the linear stability of the boundary layers is analyzed considering both the streamwise and circumferential curvatures of the wall. Based on the stability results, the eN method is employed to predict the transition locations. Numerical calculations are performed for seven forebody shapes under six oncoming flow velocities, allowing the influences of the forebody shapes and the oncoming flow velocities on the transition to be investigated. For the different forebody shapes, the boundary layer stability is generally the same behind the streamwise location of twice the forebody length, but varies within in the range of twice the forebody length. The transition locations are significantly different for the different forebody shapes. As the oncoming flow velocity increases, the dimensional unstable zone expands significantly, and the transition location moves upstream. The SUBOFF forebody shape proposed by Groves et al. [“Geometric characteristics of DARPA SUBOFF models (DTRC model numbers 5470 and 5471),” Report No. DTRC/SHD-1298-01 (David Taylor Research Center, West Bethesda, MD, 1989)] has a particularly late transition location and a large diameter close to the leading edge. This delayed transition location is caused by two separated unstable zones. Considering multiple factors, our analyses indicate that the SUBOFF forebody shape is quite valuable for practical engineering problems.
Birthing of a daughter vesicle in a model system for self-reproduction vesicles
Authors: Khunpetch Petch , Sakuma Yuka , Imai Masayuki , Kawakatsu Toshihiro
Published: July 2021

Sakuma and Imai [Phys. Rev. Lett. 107, 198101 (2011)] established a temperature-controlled cyclic process for a model system of self-reproducing vesicles without feeding. The vesicle generates a smaller inclusion vesicle called “daughter vesicle” inside the original vesicle (we call this “mother vesicle”) and then the daughter vesicle is expelled through a small pore on the mother vesicle. This self-reproducing process is called birthing. In the present study, we present a theoretical model on the birthing process of a single, rigid daughter vesicle through a pore. By using a simple geometric picture, we derive the free energy constituting the material properties of the bending, stretching, and line tension moduli of the mother vesicle, as a function of the distance between the centers of the daughter and mother vesicles, and the size of the daughter vesicle. We see clearly the disappearance of the energy barrier by selecting appropriate moduli. The dynamics of the system is studied by employing the Onsager principle. The results indicate that translocation time decreases as the friction parameter decreases or the initial size of the daughter vesicle decreases.
On the molecular correlations that result in field-dependent conductivities in electrolyte solutions
Authors: Lesnicki Dominika , Gao Chloe Y. , Limmer David T. , Rotenberg Benjamin
Published: July 2021

Employing recent advances in response theory and nonequilibrium ensemble reweighting, we study the dynamic and static correlations that give rise to an electric field-dependent ionic conductivity in electrolyte solutions. We consider solutions modeled with both implicit and explicit solvents, with different dielectric properties, and at multiple concentrations. Implicit solvent models at low concentrations and small dielectric constants exhibit strongly field-dependent conductivities. We compare these results to Onsager–Wilson theory of the Wien effect, which provides a qualitatively consistent prediction at low concentrations and high static dielectric constants but is inconsistent away from these regimes. The origin of the discrepancy is found to be increased ion correlations under these conditions. Explicit solvent effects act to suppress nonlinear responses, yielding a weakly field-dependent conductivity over the range of physically realizable field strengths. By decomposing the relevant time correlation functions, we find that the insensitivity of the conductivity to the field results from the persistent frictional forces on the ions from the solvent. Our findings illustrate the utility of nonequilibrium response theory in rationalizing nonlinear transport behavior.
Nonlinear vibration of a moving flexible printed electron web under multiphysics dynamics
Authors: Ying Shu-Di , Wu Ji-Mei , Wang Yan
Published: July 2021

Flexible electronic printing technology is a scientific technology that uses an “ink” material with conductive, dielectric, or semiconductor properties printed on a flexible web substrate to achieve precise preparation of flexible electronic devices, which are widely used in information, energy, medical, and military fields. In the preparation of the printing process of flexible printed electron webs under complex working conditions, the moving web will experience substantial unstable nonlinear dynamic behavior, such as divergence, flutter, bifurcation, and chaos. Accordingly, because of the coupling effects of the complex working conditions of the magnetic field, air and nonlinear electrostatic field forces, it is indispensable to explore the nonlinear dynamic equation of the flexible printed electron web in motion. The theory of multiphysics dynamics establishes a nonlinear vibration equation for the flexible printed electron web under multiphysics conditions. The discrete nonlinear vibration equation of state space equation was obtained by the Bubnov–Galerkin method. Utilizing the Runge–Kutta technique of the fourth-order, Poincaré maps, phase-plane diagrams, power spectra, bifurcation graphs, and time history diagrams of the moving flexible printed electron web were obtained. The influences of the velocity, electrostatic field, magnetic induction intensity, and follower force on the flexible printed electron web were analyzed. In addition, the Ansoft Maxwell finite element simulation software was used to simulate the magnetic field distribution of the moving web during roll-to-roll transmission. This paper determines the stable working range of the moving flexible printed electron web, which provides a theoretical basis for the preparation of flexible printed electronic webs.
Terahertz cut-wire-pair metamaterial absorber
Authors: Dinh Minh Q. , Thuy Le Minh , Tung Ngo Son , Van Huynh Tran , Thanh Tung Nguyen
Published: July 2021

Metamaterial absorbers are usually made of resonant structures backed by a metallic reflector, relying solely on the ohmic and dielectric losses generated by magnetic resonance. In this work, we apply an alternate approach to obtain absorption by overlapping magnetic and electric resonances in a conventional cut-wire-pair metamaterial. A terahertz absorber is designed following that approach achieving up to 99% absorption in simulations without employing a reflector, while the fabricated prototype absorbs up to 82% (excluding the loss of the silicon wafer) of the incident waves at 56 THz. The results empirically confirm that perfect absorption can be obtained using resonance superposition. In addition, the high absorption strength and the possibility to permit the transmission of the proposed metamaterial absorber make it different from other conventional ones.
Selective area growth of cubic gallium nitride on silicon (001) and 3C-silicon carbide (001)
Authors: Meier F. , Protte M. , Baron E. , Feneberg M. , Goldhahn R. , Reuter D. , As D. J.
Published: July 2021

Selective area growth of cubic gallium nitride is investigated in a plasma assisted molecular beam epitaxy setup. 380 μm thick silicon (001) and 10 μm thick 3C-silicon carbide (001), grown on 500 μm silicon (001), were used as substrates and structured with silicon dioxide masks. Selective area growth on silicon and 3C-silicon carbide was tested for both thermal and plasma deposited oxides. Multiple growth series showed that gallium nitride coverage of silicon dioxide vanished at growth temperatures of 870 °C for silicon substrates and at a surface temperature of 930 °C for 3C-silicon carbide substrates. Whereas gallium nitride is grown in its hexagonal form on silicon substrates, phase pure cubic gallium nitride could selectively be grown on the 3C-silicon carbide template. The cubic phase is verified by high resolution x-ray diffraction and low temperature photoluminescence measurements. The photoluminescence measurements prove that gallium nitride condensed selectively on the 3C-silicon carbide surfaces uncovered by silicon dioxide.
Electronic structure of mononuclear Cu-based molecule from density-functional theory with self-interaction correction
Authors: Karanovich Anri , Yamamoto Yoh , Jackson Koblar Alan , Park Kyungwha
Published: July 2021

We investigate the electronic structure of a planar mononuclear Cu-based molecule [Cu(C6H4S2)2]z in two oxidation states (z = −2, −1) using density-functional theory (DFT) with Fermi–Löwdin orbital (FLO) self-interaction correction (SIC). The dianionic Cu-based molecule was proposed to be a promising qubit candidate. Self-interaction error within approximate DFT functionals renders severe delocalization of electron and spin densities arising from 3d orbitals. The FLO-SIC method relies on optimization of Fermi–Löwdin orbital descriptors (FODs) with which localized occupied orbitals are constructed to create SIC potentials. Starting with many initial sets of FODs, we employ a frozen-density loop algorithm within the FLO-SIC method to study the Cu-based molecule. We find that the electronic structure of the molecule remains unchanged despite somewhat different final FOD configurations. In the dianionic state (spin S = 1/2), FLO-SIC spin density originates from the Cu d and S p orbitals with an approximate ratio of 2:1, in quantitative agreement with multireference calculations, while in the case of SIC-free DFT, the orbital ratio is reversed. Overall, FLO-SIC lowers the energies of the occupied orbitals and, in particular, the 3d orbitals unhybridized with the ligands significantly, which substantially increases the energy gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) compared to SIC-free DFT results. The FLO-SIC HOMO–LUMO gap of the dianionic state is larger than that of the monoanionic state, which is consistent with experiment. Our results suggest a positive outlook of the FLO-SIC method in the description of magnetic exchange coupling within 3d-element-based systems.
Preferential alignment and heterogeneous distribution of active non-spherical swimmers near Lagrangian coherent structures
Authors: Si Xinyu , Fang Lei
Published: July 2021

We report the interaction between active non-spherical swimmers and a long-standing flow structure, Lagrangian coherent structures (LCSs), in a weakly turbulent two-dimensional flow. Using a hybrid experimental–numerical model, we show that rod-like swimmers have a much stronger and more robust preferential alignment with attracting LCSs than with repelling LCSs. Tracing the swimmers' Lagrangian trajectories, we reveal that the preferential alignment is the consequence of the competition between the intrinsic mobility of the swimmers and the reorientation ability of the strain rate near the attracting LCSs. The strong preferential alignment with attracting LCSs further leads to a strong accumulation near the attracting LCSs. Moreover, we show the self-similarity of this accumulation, which reduces the intricate interaction to only one control parameter. Our results generically elucidate the interaction between active and non-spherical swimmers with LCSs and, thus, can be widely applied to many natural and engineered fluids.
A comparative study of hydrostatic pressure treated environmentally friendly perovskites CsXBr3 (X = Ge/Sn) for optoelectronic applications
Authors: Islam M. A. , Rahaman Md. Zahidur , Sen Sapan Kumar
Published: July 2021

All-inorganic cubic cesium germanium bromide (CsGeBr3) and cesium tin bromide (CsSnBr3) perovskites have attracted much attention because of their outstanding optoelectronic properties that lead to many modern technological applications. During their evolution process, it can be helpful to decipher the pressure dependence of structural, optical, electronic, and mechanical properties of CsXBr3 (X = Ge/Sn) based on ab initio simulations. The lattice parameter and unit cell volume have been decreased by applying pressure. This study reveals that the absorption peak of CsXBr3 (X = Ge/Sn) perovskites is radically changed toward the lower photon energy region with the applied pressure. In addition, the conductivity, reflectivity, and dielectric constant have an increasing tendency under pressure. The study of electronic properties suggested that CsXBr3 (X = Ge/Sn) perovskites have a direct energy bandgap. It is also found through the study of mechanical properties that CsXBr3 (X = Ge/Sn) perovskites are ductile under ambient conditions and their ductility has been significantly improved with pressure. The analysis of bulk modulus, shear modulus, and Young’s modulus reveals that hardness of CsXBr3 (X = Ge/Sn) perovskites has been enhanced under external pressure. These outcomes suggest that pressure has a significant effect on the physical properties of CsXBr3 (X = Ge/Sn) perovskites that might be promising for photonic applications.
Long-term monitoring informs data-poor marine species in the northern Gulf of Mexico
Authors: Midway Stephen R. , Erickson Kenneth A. , Kaller Michael D. , Kelso William
Published: July 2021

Fisheries monitoring programs around the world are often designed to provide information on a wide range of species that come into contact with the program gear(s). Such programs may provide untapped abundance and distribution data for species of greatest conservation need (SGCN) and other rare or data-deficient species. We examined >30 years of fish sampling data from coastal Louisiana and found that 13 of 18 SGCN marine fishes were represented in existing routine monitoring data. Although some species were rarely reported, >100 records were available for seven species, with some species being reported several thousand times. Using these records, we were able to provide species-specific information about gear, season, location and timing for several marine fishes that were considered largely unknown. Given the paucity of information available for these species and the rapidly changing Louisiana coast, these biogeographic data may be important in the development of future conservation and management programs.
Northern brown bandicoot (
Authors: Davies Hugh F. , Rangers Tiwi Land , Nicholson Emily , Murphy Brett P.
Published: July 2021

Despite the ongoing collapse of native mammal populations across northern Australia, the paucity of robust estimates of population density limits our capacity to identify and understand population change. Here we aimed to provide the first estimates of native mammal density on the Tiwi Islands – one of Australia’s largest remaining refuge areas for native mammals. We conducted intensive live-trapping at four sites that represent varying combinations of fire frequency, feral cat density and feral herbivore presence. We used spatially-explicit capture-recapture models to investigate the density of common brushtail possum (Trichosurus vulpecula) and northern brown bandicoot (Isoodon macrourus). Compared with mainland northern Australia, populations of common brushtail possum and northern brown bandicoot have remained relatively healthy on the Tiwi Islands. Common brushtail possum density was significantly higher on Bathurst Island (1.06 possum ha−1) compared with Melville Island (0.32 possum ha−1), whereas northern brown bandicoot density varied across all four sites (ranging from 0.04 to 0.34 bandicoot ha−1). Unexpectedly, the very frequently burnt Ranku site (Bathurst Island) continues to support healthy populations of both species. These density estimates provide critical information for identifying and understanding future population change for two species that have suffered marked declines across the Australian monsoon tropics. Although the lack of replication limits our ability to draw conclusions regarding the ecological constraints of these mammal populations, our density observations align with a recent conceptual model postulating that the persistence of native mammal populations across northern Australian savannas reflects a complex, but spatially-variable interplay of ‘bottom-up’ and ‘top-down’ processes.
Indications of positive feedbacks to flammability through fuel structure after high-severity fire in temperate eucalypt forests
Authors: Karna Yogendra K. , Penman Trent D. , Aponte Cristina , Gutekunst Cordula , Bennett Lauren T.
Published: July 2021

Forest fire severity influences post-fire fuel structure and thus the behaviour of subsequent fires. Understanding such interactions is critical to improving predictions of fire risk and emergency management, yet few studies have quantified fire severity effects on fuel attributes. We quantify fuel structure of a fire-tolerant eucalypt forest 7 years after a landscape-scale wildfire in south-eastern Australia. We used high-density airborne lidar data to estimate understorey fuel metrics in three strata representing horizontal and vertical connectivity in 1084 plots (0.06 ha) representing four wildfire severities (unburnt, low, moderate, high). Fuel structure was changed by high-severity fire, which significantly increased the cover and horizontal connectivity of the elevated and midstorey strata and decreased space between the understorey and canopy relative to other severity types. Random Forest models indicated that understorey fuel metrics were most influenced by wildfire severity, pre-fire values of each metric, and post-fire canopy cover, and least influenced by climatic and topographic variables. Our study provides evidence of positive feedbacks to flammability by high-severity wildfire in fire-tolerant eucalypt forests through increased horizontal and vertical fuel connectivity. It demonstrates the utility of airborne lidar data for quantifying fuel structure in complex forests and providing critical data for fire risk assessments.
Historic and bioarchaeological evidence supports late onset of post-Columbian epidemics in Native California
Authors: Jones Terry L. , Schwitalla Al W. , Pilloud Marin A. , Johnson John R. , Paine Richard R. , Codding Brian F.
Published: July 2021

Significance

The idea of precipitous continent-wide population decline beginning ca. 1492 has long influenced ecological and social narratives of North America. We analyze the largest systematic dataset of mortality records (n= 33,715 individuals) yet compiled across North America coupling archaeological and historic data to evaluate the nature and timing of Indigenous depopulation in what is now called central California. Findings indicate that mortality risk consistent with a plague-like age-at-death structure began after sustained contact with European invaders ca. AD 1770, suggesting that major depopulation began relatively late in this and possibly other isolated regions of North America. Our analysis does not support a "rebound" in native flora and fauna as a consequence of hypothesized epidemics before the first colonial settlements.
Birds use individually consistent temperature cues to time their migration departure
Authors: Burnside Robert J. , Salliss Daniel , Collar Nigel J. , Dolman Paul M.
Published: July 2021

Significance

Whether migratory populations are preadapted or constrained in responding to global climate change largely depends on which cues individuals use when deciding to start their migration. The identity of these cues is revealed by whether response thresholds are consistent within, but differ between, individuals (“repeatability”). By satellite tracking 48 individuals across multiple migrations, we show that 1) Asian houbara used the environmental cue of local temperature, which was correlated between wintering and breeding grounds, to time their spring migration departure; 2) departure responses to temperature varied between individuals but were individually repeatable; and 3) individuals’ use of temperature as a cue allowed for adaptive population-level change in migration timing, relative to annual variation in spring temperatures.
Direct evidence of a prey depletion “halo” surrounding a pelagic predator colony
Authors: Weber Sam B. , Richardson Andrew J. , Brown Judith , Bolton Mark , Clark Bethany L. , Godley Brendan J. , Leat Eliza , Oppel Steffen , Shearer Laura , Soetaert Karline E. R. , Weber Nicola , Broderick Annette C.
Published: July 2021

Significance

Elucidating the mechanisms that regulate animal populations is a fundamental goal in ecology and is increasingly important at a time of unprecedented anthropogenic disturbance to ecosystems. Here, we present direct evidence of a phenomenon known as “Ashmole’s halo”: a zone of prey depletion that is hypothesized to form around aggregations of central-place foraging predators and is believed to be the principal mechanism regulating populations of many colonially breeding animals. In effect, Ashmole’s halo constitutes rare, visible evidence of the food limitation that naturally limits many predator populations and can be exacerbated by human impacts such as fisheries. Therefore, the large extent of the resource footprint we demonstrate has important implications for conservation of marine food webs at ecologically relevant scales.
Effect of boron on mechanical and anti-corrosion properties of Al0.3CoFeMnNi high-entropy alloys
Authors: Wang Hui , Wang Tao
Published: July 2021

A series of Al0.3CoFeMnNiB x high-entropy alloys ( x = 0−0.5 in molar ratio) were prepared by vacuum arc melting method. The as-cast Al0.3CoFeMnNi alloy possesses face-centered cubic crystal structure. With boron addition, interdendritic borides are formed. The volume fraction and size of the borides increase with the enhancement of the boron content. The hardness dramatically rises from 4.04 GPa to 8.06 GPa with improving x from 0 to 0.5. The maximum yield strength and compressive strength were found to be 1050 and 1710 MPa, respectively, when x is 0.4. The compressive strain continuously decreases from 37.0% to 24.9% as x increasing from 0.2 to 0.5. The corrosion resistance gradually degrades with increasing the boron content.
The Physical Health and Activity of Patients under Forensic Psychiatric Care: A Scoping Review
Authors: Moss Katherine , Meurk Carla , Steele Megan L. , Heffernan Ed
Published: July 2021

We completed a scoping review to map current knowledge and identify research gaps relating to the physical health and activity of patients under forensic psychiatric care, and interventions to improve physical health and activity. Twenty-four articles comprising 22 studies were included in the review. There was a high prevalence of overweight and obesity among forensic patients and weight gain often occurred following admission. Interventions showed some health benefits, but there is insufficient evidence. Future research could benefit from adapting approaches evaluated in general mental health services. Future interventions should consider co-design and assess implementation factors and cost-effectiveness.
Cortical processing during table tennis ‐ an fNIRS study in experts and novices
Authors: Carius Daniel , Kenville Rouven , Maudrich Dennis , Riechel Jan , Lenz Hannes , Ragert Patrick
Published: July 2021

Among the many factors that determine top athletic performance, little is known about the contribution of the brain. With the present study, we aimed to uncover aspects of this role by examining modulatory differences in brain processing as a function of expertise and task complexity in table tennis. For this purpose, 28 right‐handed volunteers (14 experts and 14 novices) performed two table tennis strokes in a standardized manner. Hemodynamic response alterations reflecting neuronal activation were recorded during task execution using functional near‐infrared spectroscopy (fNIRS) and analyzed within and between groups. Our results showed localized activation patterns in motor areas (primary motor cortex (M1), premotor cortex (PMC), and inferior parietal cortex (IPC)) for experts and novices. Compared to novices, experts completed more table tennis strokes and showed a significant increase in hemodynamic response alterations in channels corresponding to motor areas. Furthermore, we found significant correlations between the number of strokes and hemodynamic response magnitudes in individual channels of M1, PMC, and IPC. Taken together, our findings show that table tennis performance is accompanied by extensive activation of M1, PMC, and IPC. Furthermore, the observed difference in behavioral performance between experts and novices was associated with increased activation in M1, PMC, and IPC. We postulate that these differences in brain processing between experts and novices potentially imply modulatory distinctions related to increased movement speed or frequency but may also reflect an increased task familiarity of the experts.
HIFs: New arginine mimic inhibitors of the Hv1 channel with improved VSD–ligand interactions
Authors: Zhao Chang , Hong Liang , Galpin Jason D. , Riahi Saleh , Lim Victoria T. , Webster Parker D. , Tobias Douglas J. , Ahern Christopher A. , Tombola Francesco
Published: July 2021

The human voltage-gated proton channel Hv1 is a drug target for cancer, ischemic stroke, and neuroinflammation. It resides on the plasma membrane and endocytic compartments of a variety of cell types, where it mediates outward proton movement and regulates the activity of NOX enzymes. Its voltage-sensing domain (VSD) contains a gated and proton-selective conduction pathway, which can be blocked by aromatic guanidine derivatives such as 2-guanidinobenzimidazole (2GBI). Mutation of Hv1 residue F150 to alanine (F150A) was previously found to increase 2GBI apparent binding affinity more than two orders of magnitude. Here, we explore the contribution of aromatic interactions between the inhibitor and the channel in the presence and absence of the F150A mutation, using a combination of electrophysiological recordings, classic mutagenesis, and site-specific incorporation of fluorinated phenylalanines via nonsense suppression methodology. Our data suggest that the increase in apparent binding affinity is due to a rearrangement of the binding site allowed by the smaller residue at position 150. We used this information to design new arginine mimics with improved affinity for the nonrearranged binding site of the wild-type channel. The new compounds, named “Hv1 Inhibitor Flexibles” (HIFs), consist of two “prongs,” an aminoimidazole ring, and an aromatic group connected by extended flexible linkers. Some HIF compounds display inhibitory properties that are superior to those of 2GBI, thus providing a promising scaffold for further development of high-affinity Hv1 inhibitors.
A novel Hv1 inhibitor reveals a new mechanism of inhibition of a voltage-sensing domain
Authors: Zhao Chang , Hong Liang , Riahi Saleh , Lim Victoria T. , Tobias Douglas J. , Tombola Francesco
Published: July 2021

Voltage-gated sodium, potassium, and calcium channels consist of four voltage-sensing domains (VSDs) that surround a central pore domain and transition from a down state to an up state in response to membrane depolarization. While many types of drugs bind pore domains, the number of organic molecules known to bind VSDs is limited. The Hv1 voltage-gated proton channel is made of two VSDs and does not contain a pore domain, providing a simplified model for studying how small ligands interact with VSDs. Here, we describe a ligand, named HIF, that interacts with the Hv1 VSD in the up and down states. We find that HIF rapidly inhibits proton conduction in the up state by blocking the open channel, as previously described for 2-guanidinobenzimidazole and its derivatives. HIF, however, interacts with a site slowly accessible in the down state. Functional studies and MD simulations suggest that this interaction traps the compound in a narrow pocket lined with charged residues within the VSD intracellular vestibule, which results in slow recovery from inhibition. Our findings point to a “wrench in gears” mechanism whereby side chains within the binding pocket trap the compound as the teeth of interlocking gears. We propose that the use of screening strategies designed to target binding sites with slow accessibility, similar to the one identified here, could lead to the discovery of new ligands capable of interacting with VSDs of other voltage-gated ion channels in the down state.
Heart rate variability predicts decline in sensorimotor rhythm control
Authors: Nann Marius , Haslacher David , Colucci Annalisa , Eskofier Bjoern , von Tscharner Vinzenz , Soekadar Surjo R
Published: July 2021

Objective. Voluntary control of sensorimotor rhythms (SMRs, 8–12 Hz) can be used for brain–computer interface (BCI)-based operation of an assistive hand exoskeleton, e.g. in finger paralysis after stroke. To gain SMR control, stroke survivors are usually instructed to engage in motor imagery (MI) or to attempt moving the paralyzed fingers resulting in task- or event-related desynchronization (ERD) of SMR (SMR-ERD). However, as these tasks are cognitively demanding, especially for stroke survivors suffering from cognitive impairments, BCI control performance can deteriorate considerably over time. Therefore, it would be important to identify biomarkers that predict decline in BCI control performance within an ongoing session in order to optimize the man–machine interaction scheme. Approach. Here we determine the link between BCI control performance over time and heart rate variability (HRV). Specifically, we investigated whether HRV can be used as a biomarker to predict decline of SMR-ERD control across 17 healthy participants using Granger causality. SMR-ERD was visually displayed on a screen. Participants were instructed to engage in MI-based SMR-ERD control over two consecutive runs of 8.5 min each. During the 2nd run, task difficulty was gradually increased. Main results. While control performance (p = .18) and HRV (p = .16) remained unchanged across participants during the 1st run, during the 2nd run, both measures declined over time at high correlation (performance: −0.61%/10 s, p = 0; HRV: −0.007 ms/10 s, p < .001). We found that HRV exhibited predictive characteristics with regard to within-session BCI control performance on an individual participant level (p < .001). Significance. These results suggest that HRV can predict decline in BCI performance paving the way for adaptive BCI control paradigms, e.g. to individualize and optimize assistive BCI systems in stroke.
Driving Forces and Pressures on Organic Farming of Dragon Fruit : A Part of The DPSIR Analysis Framework
Authors: Ningsih Kustiawati , Sakdiyah Halimatus , Felani Herman , Dwiastuti Rini , Asmara Rosihan
Published: July 2021

Organic farming is a farming activity that is familiar with the environment. Western agricultural experts define organic farming as the law of return, which means a system that returns all types of organic matter to the soil, both in the form of residues and plant and livestock wastes which then aim to feed the plants. The philosophy is to give food to the soil then the land will provide food for plants (Sutanto, 2002). Organic dragon fruit farming in Pamekasan Regency has been running for 5 years, so the decision of organic farmers is a very important factor in the application of dragon fruit organic farming. There are two indicators that influence farmers’ decisions in applying dragon fruit organic farming, namely driving forces and pressures. The research method used is DPSIR (Driving Forces-Pressures-State-Impact-Responses). However, in this study limiting analysis is only an element of Driving Forces and Pressures. The way to retrieve data is by in-depth study or in-depth interviews with 34 organic dragon fruit farmers. The results showed that there were 6 things that became driving forces of farmers’ decisions in implementing dragon fruit organic farming, namely: (1) Unoptimal Use of Agricultural Land, (2) Lack of Irrigation Infrastructure and Management, (3) Lack of Farmers Knowledge about Pest and Disease Management, (4) Low Agricultural Quality due to Excessive Use of Chemical Fertilizers and Pesticides, (5) Respondents and Experiences of Organic Dragon Fruit Farming Education Levels are Short Term and (6) Lack of Infrastructure Availability to Support Organic Fruit Farming Fields Dragon. Meanwhile Pressures that influence farmers’ decisions in applying dragon fruit organic farming are: (1) Ability to reduce the use of chemicals, (2) The use of organic matter is still lacking, (3) Lack of effort to prevent soil erosion and ( 4) Lack of awareness to increase land security capacity.
Sustainable Hospitality and Revisit Intention in Tourism Services
Authors: Nugroho I , Hanafie R , Rahayu Y I , Sudiyono  , Suprihana  , Yuniar H R , Azizah R , Hasanah R
Published: July 2021

Hospitality has an important role for the sustainability of tourism services. Efforts to measure the sustainability of hospitality are relevant for dealing with this. This research aims to study the factors related to hospitality and measure the index of hospitality sustainability. The study was conducted at the tourist destination Sumberawan, Singosari district, Malang regency. The study involved 38 students as respondents. Variables of hospitality, invitation, comfort, empathy, satisfaction, and revisit intention were explored through a survey. Path modeling - part least square (PM-PLS) and multi-dimension scale (MDS) is used in the study. The results showed that hospitality is significantly influenced by comfort and empathy. Hospitality also affects satisfaction, and then satisfaction affects revisit intention. Furthermore, satisfaction becomes a mediating relationship between hospitality and revisit intention. All variables included in the category of less sustainable, with a sustainability index of 37.11, 40.84 and 37.57. Five indicators to improve the sustainability index are customers treated kindly, friendly employees, fulfillment of service standards, return visits to tourist sites, and willingness to recommend others.