bluuebunny/crossref_metadata_2025 huggingface dataset:
Physics-informed machine learning model for bias temperature instability
Authors: Lee Jonghwan
Published: February 2021

A new machine learning model is presented to predict the dynamic behavior of threshold voltage shifts induced by bias temperature instability (BTI) in CMOS devices. The model is constructed by combining physical theories with machine learning such as an artificial neural network and a Gaussian mixture model (GMM). To enlarge the capture–emission energy (CEE) window and to perform independent estimations of two distinct components of CEE distribution, the GMM with soft clustering is utilized, enabling full lifetime modeling of BTI. By training the CEE map with the consideration of the occupancy probability of traps and then executing the integration along the CEE, the threshold voltage shifts are obtained. This approach forms data-driven modeling that naturally encodes underlying physical theories as prior information. The resulting model exhibits a good performance for predicting the dynamic characteristics of BTI under various stress-recovery conditions.
On-chip thin-film microtransformer with improved coupling factor for high frequency data transmission
Authors: Dinulovic Dragan , Shousha Mahmoud , Haug Martin
Published: February 2021

An on-chip thin-film microtransformer with an improved coupling factor is shown in this paper. In addition to the development of this component, the characterization of the microtransformer and its use in the data transmission application are presented. In comparison to previous work, this microtransformer device shows an improved coupling factor. The microtransformer is fabricated on silicon substrate using thin-film technology. The fabrication is based on damascene process and combines material deposition using only sputtering PVD (physical vapor deposition) or CVD a (chemical vapor deposition) processes and chemical-mechanical polishing (CMP) process for patterning. The microtransformer design is a solenoid type device with a magnetic bar core and interleaved winding style. For a magnetic core a CoFeB material is applied. As insulation materials, silicon dioxide and silicon nitride are implemented. The device chip size is 1.6 mm x 0.8 mm. A turns ratio of the microtransformer is 1:1, and the device shows a self-inductance of about 25 nH and an improved coupling factor with a value of 60%.
Developing and piloting an adaptable oxycodone quality improvement strategy: steps towards opioid stewardship
Authors: Pattullo Champika , Suckling Benita , Taylor Sally , Thomson Jonathan , Collins Gareth , Hall Lisa , Donovan Peter
Published: February 2021

Objective In recent years, there have been considerable increases in both the utilisation and reported harms of prescription opioids in Australia. This report details the development of adaptable resources, implementation and the evaluation of pilot projects that optimise oxycodone prescribing and introduce concepts of opioid stewardship into hospital settings. Methods An adaptable suite of resources, based on principles of implementation science, was developed and used to facilitate the projects. Local prescribing practice audits of oxycodone guided the development of context-sensitive educational strategies that were piloted and evaluated in a repeat audit. The primary outcome was the proportion of oxycodone prescriptions indicating tailored prescribing practices. In emergency departments (EDs), a prescription was considered tailored if it was for ≤10 tablets. In surgery, tailored prescriptions were those given to patients who had required opioids in the 24 h before discharge. Results Cumulative results of the pilot projects in three EDs demonstrated improved rates of tailored oxycodone prescribing on discharge (62% vs 90%; P < 0.0001). In the surgical setting of one hospital, tailored prescribing increased significantly (from 76% to 91%; P = 0.013) and was accompanied by a halving of the proportion of patients receiving oxycodone prescriptions (36% vs 18%; P < 0.001). Conclusions The implementation of facilitated, adaptable, prescriber-led quality improvement projects significantly improved tailored oxycodone prescribing practices and provides a platform to advance further opioid-related practice improvement in Australia. What is known about the topic? The increasing trend in opioid prescribing, misuse, harm and death in Australia, and the potential for hospital prescribing to contribute to long-term opioid use, is well known. Recent changes to the Pharmaceutical Benefits Scheme are designed to help better identify patients who need oxycodone on discharge and the quantity to prescribe, rather than default prescribing. However, how to implement tailored prescribing has not been described in detail in the Australian literature. What does this paper add? This paper adds to the mass of literature describing the ‘problem’ of opioid prescribing by providing a ‘solution’ in the form of evidence for the implementation of a facilitated and adaptable quality improvement strategy in emergency and surgical settings. The focus is not on a reduction of opioids, but rather on providing tailored pain management and opioid prescribing. What are the implications for practitioners? This paper provides a practical, pragmatic and achievable starting point for other Australian practitioners to adapt the described processes and take the first steps towards opioid stewardship in their setting.
Steroid regulation of secreted phosphoprotein 1 (SPP1) expression in ovine endometrium
Authors: Tremaine Tina D. , Fouladi-Nashta Ali A.
Published: February 2021

Secreted phosphoprotein 1 (SPP1) is an extracellular matrix glycoprotein that is highly expressed at the maternal–fetal interface and is a critical mediator of embryo implantation. The objectives of this study were to examine the spatial and temporal cyclical expression patterns and steroid regulation of SPP1 mRNA and protein in ovine endometrium, which may be further indicative of their functionality in embryo implantation. Uterine tissue was obtained following hysterectomy from ovariectomised ewes treated with ovarian steroids. In parallel, invitro culture of endometrial cells was used to investigate the effects of ovarian steroids on SPP1 expression in endometrial and luminal epithelial (LE) cells. A significant sustained mid-luteal phase increase in SPP1 mRNA in intercaruncular regions of the endometrium was observed, indicating that glandular epithelium is likely to be the primary source of SPP1 production. This increase in SPP1 was induced by progesterone treatment and was shown at the protein level by immunohistochemistry analysis. Similarly, treatment of stromal cells with 10ng mL−1 progesterone or in combination with 1ng mL−1 oestradiol significantly increased SPP1 expression (P<0.05). Collectively, expression levels of SPP1 are cycle-dependent and peak in the progesterone-dominant luteal phase. They are dependent on the interaction of uterine LE and stromal cells and may involve paracrine signalling by progesterone receptor-positive stromal cells.
Super Hamiltonian in superspace for incommensurate superlattices and quasicrystals
Authors: Valiente M , Duncan C W , Zinner N T
Published: February 2021

Infinite quasiperiodic arrangements in space, such as quasicrystals, are typically described as projections of higher-dimensional periodic lattices onto the physical dimension. The concept of a reference higher-dimensional space, called a superspace, has proved useful in relation to quasiperiodic systems. Although some quantum-mechanical systems in quasiperiodic media have been shown to admit quasiperiodic states, any sort of general Hamiltonian formalism in superspace is lacking to this date. Here, we show how to extend generic quantum-mechanical Hamiltonians to higher dimensions in such a way that eigenstates of the original Hamiltonian are obtained as projections of the Hamiltonian in superspace, which we call the super Hamiltonian. We apply the super Hamiltonian formalism to a simple, yet realistic one-dimensional quantum particle in a quasiperiodic potential without the tight-binding approximation, and obtain continuously labelled eigenstates of the system corresponding to a continuous spectrum. All states corresponding to the continuum are quasiperiodic. We also obtain the Green’s functions for continuum states in closed form and, from them, the density of states and local density of states, and scattering states off defects and impurities. The closed form of this one-dimensional Green’s function is equally valid for any continuum state in any one-dimensional single-particle quantum system admitting continuous spectrum. With the basis set we use, which is periodic in superspace, and therefore quasiperiodic in physical space, we find that Anderson-localised states are also quasiperiodic if distributional solutions are admitted, but circumvent this difficulty by generalising the superspace method to open boundary conditions. We also obtain an accurate estimate of the critical point where the ground state of the system changes from delocalised to Anderson localised, and of the critical exponent for the effective mass. Finally, we calculate, within the superspace formalism, topological edge states for the semi-infinite system, and observe that these exist, in the delocalised phase, within all spectral gaps we have been able to resolve. Our formalism opens up a plethora of possibilities for studying the physics of electrons, atoms or light in quasicrystalline and other aperiodic media.
Interband optical absorption obtained by pseudopotential method for type-II InAs/GaSb SL photodetectors
Authors: Akel Kazım , Hoştut Mustafa , Akın Tayfun , Ergün Yüksel
Published: February 2021

We have calculated interband optical absorption for InAs/GaSb based type-II superlattice (SL) structures. The empirical pseudopotential method (EPM) has been used as an alternative to the k.p method since it is less sophisticated while providing similar results in the mid wavelength infrared range and long wavelength infrared range atmospherics bands for comparison. EPM results show that the bandgap wavelengths of SLs have been predicted with the underestimating of 0.4 µm. This corresponds to an uncertainty of less than 0.3 monolayer in the layer width. The theoretical estimation is comparable with the uncertainty of the layer width during the growth process. Heterostructures or SLs with their ternary and quaternary alloys can be calculated by this method to identify electronic and optical parameters for both intersubband and interband applications.
Machine learning approach to muon spectroscopy analysis
Authors: Tula T , Möller G , Quintanilla J , Giblin S R , Hillier A D , McCabe E E , Ramos S , Barker D S , Gibson S
Published: February 2021

In recent years, artificial intelligence techniques have proved to be very successful when applied to problems in physical sciences. Here we apply an unsupervised machine learning (ML) algorithm called principal component analysis (PCA) as a tool to analyse the data from muon spectroscopy experiments. Specifically, we apply the ML technique to detect phase transitions in various materials. The measured quantity in muon spectroscopy is an asymmetry function, which may hold information about the distribution of the intrinsic magnetic field in combination with the dynamics of the sample. Sharp changes of shape of asymmetry functions—measured at different temperatures—might indicate a phase transition. Existing methods of processing the muon spectroscopy data are based on regression analysis, but choosing the right fitting function requires knowledge about the underlying physics of the probed material. Conversely, PCA focuses on small differences in the asymmetry curves and works without any prior assumptions about the studied samples. We discovered that the PCA method works well in detecting phase transitions in muon spectroscopy experiments and can serve as an alternative to current analysis, especially if the physics of the studied material are not entirely known. Additionally, we found out that our ML technique seems to work best with large numbers of measurements, regardless of whether the algorithm takes data only for a single material or whether the analysis is performed simultaneously for many materials with different physical properties.
Ablation of cells in mice using antibody-functionalized multiwalled carbon nanotubes (Ab-MWCNTs) in combination with microwaves
Authors: Chall Amy , Stagg John , Mixson Andrew , Gato Eric , Quirino Rafael L , Sittaramane Vinoth
Published: February 2021

This is a proof-of-principle study on the combination of microwaves and multiwalled carbon nanotubes to induce in vivo, localized hyperthermic ablation of cells as a potential methodology for the treatment of localized tumors. Compared to conventional methods, the proposed approach can create higher temperatures in a rapid and localized fashion, under low radiation levels, eliminating some of the unwanted side effects. Following successful ablation of cancer cells in cell culture and zebrafish tumor-xenograft models, it is hypothesized that a cancer treatment can be developed using safe microwave irradiation for selective ablation of tumor cells in vivo using carbon nanotube-Antibody (CNT-Ab) conjugates as a targeting agent. In this study, mice were used as an animal model for the optimization of the proposed microwave treatment strategy. The safe dose of CNT-Ab and microwave radiation levels for mice were determined. Further, CNT-Ab distribution and toxicology in mice were qualitatively determined for a time span of two weeks following microwave hyperthermia. The results indicate no toxicity associated with the CNT-Ab in the absence of microwaves. CNTs are only found in the proximity of the site of injection and have been shown to effectively cause hyperthermia induced necrosis upon exposure to microwaves with no noticeable damage to other tissues that are not in direct contact with the CNT-Ab. To understand the cellular immune response towards CNT-Abs, transgenic zebrafish with fluorescently labeled macrophages and neutrophils were used to assay for their ability to phagocytize CNT-Ab. Our results indicate that macrophages and neutrophils were able to actively phagocytose CNT-Abs shortly after injection. Taken together, this is the first study to show that CNTs can be used in combination with microwaves to cause targeted ablation of cells in mice without any side effects, which would be ideal for cancer therapies.
A capacitive humidity sensor based on all-protein embedded with gold nanoparticles @ carbon composite for human respiration detection
Authors: Ma Liyun , Patil Aniruddha , Wu Ronghui , Zhang Yifan , Meng Zhaohui , Zhang Wenli , Kong Lingqing , Liu Xiang Yang , Wang Jun
Published: February 2021

Wool and silk fiber are the most extensive resources of protein fibers and have been used in the textile field for many years. The extracted biocompatible proteins are more and more widely used in flexible devices, sensors, tissue engineering, etc. Here, a fully biomaterial based flexible humidity sensor has been successfully fabricated for the first time. Interdigital electrodes of humidity sensor are printed on a transparent sensor substrate made of silk protein by inkjet printing. The humidity sensitive material is gold nanoparticles hosted nitrogen doped carbon (AuNPs@NC), which is fabricated by in situ dispersion of gold nanoparticles in a wool keratin assisted porous carbon precursor. The best treatment condition of the sensitive materials is obtained by comparing the sensitivity of humidity response. Moreover, the as-prepared biocompatible flexible sensor was successfully used to detect human respiration.
DeepDose: a robust deep learning-based dose engine for abdominal tumours in a 1.5 T MRI radiotherapy system
Authors: Tsekas G , Bol G H , Raaymakers B W , Kontaxis C
Published: February 2021

We present a robust deep learning-based framework for dose calculations of abdominal tumours in a 1.5 T MRI radiotherapy system. For a set of patient plans, a convolutional neural network is trained on the dose of individual multi-leaf-collimator segments following the DeepDose framework. It can then be used to predict the dose distribution per segment for a set of patient anatomies. The network was trained using data from three anatomical sites of the abdomen: prostate, rectal and oligometastatic tumours. A total of 216 patient fractions were used, previously treated in our clinic with fixed-beam IMRT using the Elekta MR-linac. For the purpose of training, 176 fractions were used with random gantry angles assigned to each segment, while 20 fractions were used for the validation of the network. The ground truth data were calculated with a Monte Carlo dose engine at 1% statistical uncertainty per segment. For a total of 20 independent abdominal test fractions with the clinical angles, the network was able to accurately predict the dose distributions, achieving 99.4% ± 0.6% for the whole plan prediction at the 3%/3 mm gamma test. The average dose difference and standard deviation per segment was 0.3% ± 0.7%. Additional dose prediction on one cervical and one pancreatic case yielded high dose agreement of 99.9% and 99.8% respectively for the 3%/3 mm criterion. Overall, we show that our deep learning-based dose engine calculates highly accurate dose distributions for a variety of abdominal tumour sites treated on the MR-linac, in terms of performance and generality.
The time response for the low-temperature poly-silicon thin-film transistors to x-ray irradiation pulse
Authors: Tai Ya-Hsiang , Yeh Shan , Chen Wei-Lin , Chang Ting-Chang
Published: February 2021

In this study, the time response behavior of low-temperature polycrystalline silicon (LTPS) thin-film transistors (TFTs) to x-ray irradiation pulses with different frequencies is analyzed. The formulas for the time response of excited and recovery behaviors are proposed for possible use in circuit performance enhancement in real x-ray irradiation situations. The predicted and measured results fit fairly well, which is important in the development of x-ray image sensors using LTPS TFTs.
Improvement of critical temperature of niobium nitride deposited on 8-inch silicon wafers thanks to an AlN buffer layer
Authors: Rhazi Raouia , Machhadani Houssaine , Bougerol Catherine , Lequien Stéphane , Robin Eric , Rodriguez Guillaume , Souil Richard , Thomassin Jean-Luc , Mollard Nicolas , Désières Yohan , Monroy Eva , Olivier Ségolène , Gérard Jean-Michel
Published: February 2021

In this paper, we study the crystalline properties and superconducting critical temperature of ultra-thin (5–9 nm) NbN films deposited on 8-inch silicon wafers by reactive sputtering. We show that the deposition of NbN on a thin (10–20 nm) AlN buffer layer, also synthesized by reactive sputtering, improves the critical temperature by several Kelvin, up to 10 K for 9 nm NbN on 20 nm AlN. We correlate this improvement to the higher-crystalline quality of NbN on AlN. While NbN deposited directly on silicon is polycrystalline with randomly oriented grains, NbN on AlN(0001) is textured along (111), due to the close lattice match. The superconducting properties of the NbN/AlN stack are validated by the demonstration of fibre-coupled normal-incidence superconducting nanowire single photon detectors. The whole fabrication process is CMOS compatible, with a thermal budget compatible with the integration of other passive and active components on silicon. These results pave the way for the integration of a large number of surface or waveguide-integrated detectors on large-scale silicon wafers. Furthermore, as AlN is transparent over a broad wavelength range from the visible to the near-infrared, the optimized superconducting NbN/AlN stack can be used for a wide variety of applications, from imaging to quantum communications and quantum computing.
Comment on ‘On the criteria of the Langmuir oscillations breaking in a plasma’
Authors: Rathee Nidhi
Published: February 2021

In a recent article by Frolov and Chizhonkov [Phys. Scr.
95 065604, (2020)], the authors have claimed that the inequality condition on initial electron density and velocity for plasma to sustain oscillation is incorrect in the book Methods in Nonlinear Plasma Theory by Davidson. The purpose of this note is to show the equivalence of both the inequalities as derived by Davidson and by Frolov et al.
Performance analysis of octagonal photonic crystal fiber (O-PCF) for various communication applications
Authors: Hossain Md. Selim , Sen Shuvo , Hossain Md. Mahabub
Published: February 2021

In this research work, a novel design of octagonal cladding with two elliptical cores in photonic crystal fiber (O-PCF) is studied for application in the terahertz (THz) frequency regime. There exists five layers octagonal figure in circular air holes (CAH) of cladding region with two elliptical shapes of core area are proposed in this research work. The O-PCF features of the fiber have been explored using full vector finite element method (FEM) with perfectly match layer (PML) boundary condition that have been used to confine the light inside the core region properly. Some supplementary significant fiber features for THz signal spread with low confinement loss, high core power fraction, scattering loss and single-mode PCF circumstances of the fiber have also been considered. Simulated results exhibition compares to the low effective material loss (EML) of 0.0153 cm−1, larger effective area of 5.95 × 10–8 m2, core power fraction of 79%, a low confinement loss and scattering loss such as 3.36 × 10–14 dB m−1 and 1.25 × 10–10 dB km−1 respectively at 1 THz frequency regime. To shorten design and smooth fabrication, only circular shaped air holes have been employed. Due to its promising characteristics, the proposed SM-OPCF waveguide provides efficient transmission of broadband terahertz signals. The suggested excellent designed of O-PCF can be used mostly for in nano-optics, biomedical signal processing, optical amplification, SONET and others communication areas.
Preparation, characterization, and optical properties of nanosized Al(III) 3-azo-phenolate salicylic acid thin film for potential application in nonlinear optical crystal
Authors: Hamdalla Taymour A , Algamdi S A , Aljohani Meshari M , Darwish A A A , Mohamed Asmaa K , Mahmoud Mohamed E , Seleim Seleim M
Published: February 2021

The present research is concentrated on improving the characteristic properties of salicylic acid (SA) within the nonlinear optical crystal. So, the layer-by-layer (LBL) technique was utilized to design and make thin films of nanosized aluminum (III) complex of 3-azo-phenolate salicylic acid (NS Al(III)-3AP-SA) having a high specified surface area with various thicknesses. The synthesized material was deposited on glass and quartz substrates to investigate the structural and optical properties. Characterization of fabricated films was performed using TGA, X-ray, SEM, and FTIR. The prepared NS Al(III)-3AP-SA exhibited a spherical shape with a size between 41–61 nm. The optical transmission spectra were studied in the spectral range of 300 to 1100 nm at room temperature. The refractive index, absorption coefficient, and optical energy gap were determined. It was found that the optical energy gap = 3.78 eV without noticeable variation because of thickness increases. Together with their dependencies on the film thicknesses, the nonlinear and linear optical parameters have been calculated. The results suggest that the assembled NS Al(III)-(3AP-SA) can be categorized as a promising material for the fabrication of nonlinear optical crystal applications.
Heavy ion irradiation induced defects in Zircaloy-4
Authors: Izerrouken M , Hazem R , Yahsi U , Naceri S E , Tav C , Küzeci S , Sari A , Haid F , Ishaq A , Menchi O , Ghamnia M
Published: February 2021

Radiation damage induced in Zircaloy-4 by 20 MeV Au ions was investigated using Grazing x-ray diffraction (GIXRD), positron annihilation techniques, micro-and nano-hardness techniques. The irradiations were performed at room temperature in the fluence range 1 × 1013–5 × 1014 ions cm−2 corresponding to 0.07–3.63 displacements per atom (dpa). The grazing incidence angle x-ray diffraction (GIXRD) revealed the presence of the hydride precipitates in the analyzed zircaloy-4. According to our experimental data it is found that the amount of these precipitates decreases after irradiation as emphasized by GIXRD and Positron Annihilation Lifetime Spectroscopy (PALS) results. The same data revealed also a zircaloy-4 swelling above a certain dose. From the combination of domain size/microstrain with the micro- and nano-hardness results, we conclude that the Zircaloy hardening is mainly due to the dislocation formation indicating the effect of the microstructure on the mechanical properties. Moreover, from the dose dependence of irradiation hardening we conclude that the transition point from low-dose to high-dose regime is observed around 0.07 dpa.
in BLMSSM *
Authors: Chen Jian-Bin , Zhang Meng , Xing Li-Li , Feng Tai-Fu , Zhao Shu-Min , Sun Ke-Sheng
Published: February 2021

Applying the effective Lagrangian method, we study the flavor changing neutral current process

within the minimal supersymmetric extension of the Standard Model, where baryon and lepton numbers are local gauge symmetries. Constraints on the parameters are investigated numerically with the experimental data for the branching ratio of

. Additionally, we present the corrections to direct CP-violation in

and time-dependent CP-asymmetry in

. With appropriate assumptions on the parameters, we find the direct CP-violation

is very small, while one-loop contributions to

can be significant.
Plasma confinement mode classification using a sequence-to-sequence neural network with attention
Authors: Matos F. , Menkovski V. , Pau A. , Marceca G. , Jenko F. , the TCV Team
Published: February 2021

In a typical fusion experiment, the plasma can have several possible confinement modes. At the tokamak à configuration variable, aside from the low (L) and high (H) confinement modes, an additional mode, dithering (D), is frequently observed. Developing methods that automatically detect these modes is considered to be important for future tokamak operation. Previous work (Matos et al 2020 Nucl. Fusion
60 036022) with deep learning methods, particularly convolutional long short-term memory networks (conv-LSTMs), indicates that they are a suitable approach. Nevertheless, those models are sensitive to noise in the temporal alignment of labels, and that model in particular is limited to making individual decisions taking into account only the input data at a given timestep and the past data, represented in its hidden state. In this work, we propose an architecture for a sequence-to-sequence neural network model with attention which solves both of those issues. Using a carefully calibrated dataset, we compare the performance of a conv-LSTM with that of our proposed sequence-to-sequence model, and show two results: one, that the conv-LSTM can be improved upon with new data; two, that the sequence-to-sequence model can improve the results even further, achieving excellent scores on both train and test data.
Rational nanocarrier design towards clinical translation of cancer nanotherapy
Authors: Guo Dandan , Ji Xiaotian , Luo Juntao
Published: February 2021

The past decades have witnessed an exponential growth in research of cancer nanomedicine, which has evolved into an interdisciplinary field involving chemistry, physics, biology, and pharmacology, pathophysiology, immunology and clinical science in cancer research and treatment. The application of nanoparticles in drug delivery increases the solubility and decreases the toxicity of free drug molecules. The unique feature of cancer pathophysiology, e.g. leaky blood vessel, presents a unique opportunity for nanocarriers to deliver therapeutics selectively to tumor sites based on size selectivity. However, the clinical translation of nanomedicine is mostly limited to the classical liposomal formulations and PEGylation of therapeutics. Numbers of reasons hinder the clinical translation of the novel nanoparticles developed in the last decades for drug delivery. Comprehensive understanding of the properties of nanocarriers and their interactions with the physiological and pathological interfaces is critical to design effective nanoformulations. In addition, understanding the general principles and concerns in pharmaceutical industries and clinical practice for nanotherapeutic development is essential to develop a translatable nanoformulations via rational nanocarrier designs. In this account, we will review the relationship between the physiochemical properties of nanocarriers and biodistribution, and interactions with biological and immunological systems for effective drug delivery and cancer treatments. Further, we review the strategies for rational design of nanocarriers via structure-based approach and bio-mimicking systems to facilitate the clinical translation in enhancing cancer treatment via both chemotherapy and immunotherapy.
Potential role of permafrost thaw on increasing Siberian river discharge
Authors: Wang Ping , Huang Qiwei , Pozdniakov Sergey P , Liu Shiqi , Ma Ning , Wang Tianye , Zhang Yongqiang , Yu Jingjie , Xie Jiaxin , Fu Guobin , Frolova Natalia L , Liu Changming
Published: February 2021

Despite the increasing Siberian river discharge, the sensitivity of streamflow to climate forcing/permafrost thawing is poorly quantified. Based on the Budyko framework and superposition principles, we detected and attributed the changes in streamflow regimes for the three great Siberian rivers (Ob, Yenisei, and Lena) during 1936–2019. Over the past 84 years, streamflow of Ob, Yenisei and Lena has increased by ∼7.7%, 7.4% and 22.0%, respectively. Intensified precipitation induced by a warming climate is a major contributor to increased annual streamflow. However, winter streamflow appears to be particularly sensitive to temperature. Whilst rising temperature can reduce streamflow via evapotranspiration, it can enhance groundwater discharge to rivers due to permafrost thawing. Currently, every 1 °C rise in temperature likely leads to 6.1%–10.5% increase in groundwater discharge, depending on the permafrost condition. For permafrost-developed basins, the contribution to increased streamflow from thawing permafrost will continue to increase in the context of global warming.
Trees at the Amazonia-Cerrado transition are approaching high temperature thresholds
Authors: Araújo Igor , Marimon Beatriz S , Scalon Marina C , Fauset Sophie , Marimon Junior Ben Hur , Tiwari Rakesh , Galbraith David R , Gloor Manuel U
Published: February 2021

Land regions are warming rapidly. While in a warming world at extra-tropical latitudes vegetation adapted to higher temperatures may move in from lower latitudes this is not possible in the tropics. Thus, the limits of plant functioning will determine the nature and composition of future vegetation. The most temperature sensitive component of photosynthesis is photosystem II. Here we report the thermal safety margin (difference between photosystem II thermotolerance (T50) and maximum leaf temperature) during the beginning of the dry season for four tree species co-occurring across the forest-savanna transition zone in Brazil, a region which has warmed particularly rapidly over the recent decades. The species selected are evergreen in forests but deciduous in savannas. We find that thermotolerance declines with growth temperature >40 °C for individuals in the savannas. Current maximum leaf temperatures exceed T50 in some species and will exceed T50 in a 2.5 °C warmer world in most species evaluated. Despite plasticity in leaf thermal traits to increase leaf cooling in hotter environments, the results show this is not sufficient to maintain a safe thermal safety margin in hotter savannas. Overall, the results suggest that tropical forests may become increasingly deciduous and savanna-like in the future.
Multiple environmental factors regulate the large-scale patterns of plant water use efficiency and nitrogen availability across China’s forests
Authors: Tang Songbo , Lai Yuan , Tang Xuli , Phillips Oliver L. , Liu Jianfeng , Chen Dexiang , Wen Dazhi , Wang Silong , Chen Longchi , Tian Xingjun , Kuang Yuanwen
Published: February 2021

Global changes, e.g. global warming, elevated nitrogen deposition, and shifts of precipitation regime, exert a major influence on forests via affecting plant water use efficiency (WUE) and plant nitrogen (N) availability. Large-scale ecological sampling can help us to better understand variation across regions and provide opportunities to investigate the potential impacts of multiple aspects of global change on forest ecosystem responses. Here, we determine the geographical patterns of key isotopic measures of ecosystem function—plant WUE (calculated from foliar δ
13C values) and plant N availability (assessed by foliar δ
15N values)—across China’s forests covering ∼21 latitude (∼22–43°N) and ∼28 longitude (∼93–121°E) degree, and investigate how a suite of soil, plant, and atmospheric factors regulate them. We found that plant WUE increased but N availability decreased with latitude, while plant WUE and N availability did not vary with longitudinal gradient. Different factors regulate the large-scale patterns in WUE and N availability. The mean annual temperature, atmospheric N deposition, and soil water content exhibit considerable effects on plant WUE over both the north-to-south and east-to-west transects, while the mean annual precipitation, soil potassium content, foliar N, and precipitation seasonality considerably affect the latitudinal patterns of plant N availability. In addition, the east-to-west spatial pattern in plant N availability is associated with the variation in solar radiation. Our results suggest that key forest ecological functions respond to an array of environmental factors, and imply that changes in many different environmental attributes need to be considered in order to successfully assess plant WUE and N availability responses to global changes this century.
Poincaré crystal on the one-dimensional lattice
Authors: Wang Pei
Published: February 2021

In this paper, we develop the quantum theory that has discrete Poincaré symmetry on the one-dimensional Bravais lattice. We review the recently discovered discrete Lorentz symmetry which coexists with the discrete space translational symmetry on a Bravais lattice. The discrete Lorentz transformations and spacetime translations form the discrete Poincaré group, which are represented by unitary operators in a quantum theory. We find the conditions for the existence of representation, which are expressed as the congruence relation between quasi-momentum and quasi-energy. We then build the Lorentz-invariant many-body theory of indistinguishable particles by expressing both the unitary operators and Floquet Hamiltonians in terms of the field operators. Some typical Hamiltonians include the long-range hopping which fluctuates as the distance between sites increases. We calculate the Green’s function of the theory. The spacetime points where the Green’s function is nonzero display a lattice structure. During the propagation, the particle stays localized on a single or a few sites to preserve the Lorentz symmetry.
An assessment of some physical properties of different brands of cement in Nigeria
Authors: Ogbodo Munachiso C. , Akpabot Akpabot Ifiok
Published: February 2021

The durability of infrastructures has become a significant issue starring the face of professionals in the building industry as most recently constructed structures are deficient in this regard. This study was carried out to assess the physical properties of five different brands of Portland cement commonly used in Nigeria. The specific surface method was adopted in obtaining the fineness, and the specific gravity bottle was used to determine the specific gravity of the different cement brands. The result shows that sample A had the highest fineness value of 360m2/kg and the only sample that met the ASTM standard value of 280 m2/kg. This implies that Sample A has a greater surface area for hydration which should lead to faster development of early strength and a higher rate of heat evolution. Sample E had the least fineness value of 168 m2/kg. This means that Sample E has the least surface area for hydration and should be slow in early strength gain. Sample B had the highest specific gravity value of 3.266 and the highest value of bulk density of 1462.085kg/m3. The implication is that Sample B has more moisture because it has the highest specific gravity value. The quantity of sample B that will be required in the concrete making will be less relative to other samples as it had the highest bulk density.
Seismic Performance Assessment of a Typical Peruvian Public-School Building
Authors: Cardenas O , Farfan A , Huaco G , Stavridis A
Published: February 2021

Several Peruvian public school buildings have not performed well during earthquakes, with the level of damage varying from cracks in structural elements to the complete collapse of the building. The reasons for the unsatisfactory seismic performance of the buildings include the design codes followed at the time these schools were built, and the lack of professional engineering supervision during the design and construction phases of these schools. This study focuses on a typical school building, selected after performing a survey to public schools in the district of San Juan de Miraflores in the city of Lima, in Peru. The seismic response of the selected building to various ground motions is analysed with nonlinear static and time history analyses. The results indicate that the building does not meet the minimum seismic performance level required by the current Peruvian seismic design provisions.
Effective medium approximation based interpretation for Mueller matrix spectra of polydimethylsiloxane gratings
Authors: Wang Meng , Liu Fang , Jiang Hao , Liu Shiyuan
Published: February 2021

Dielectric corrugated gratings are of considerable interest due to their applications in acousto-optics, quantum electronics, integrated optics, spectroscopy, and holography integrated optics. Rigorous coupled-wave analysis has been widely used for the analysis of dielectric gratings. However, this approach is not only time-consuming and computer intensive but it also does not really promote the physical understanding of the origin of the observed optical behavior. Here, we use Mueller matrix (MM) spectroscopic ellipsometry to systematically study the sinusoidal polydimethylsiloxane grating. We correlate the observed polarization mixing in the Mueller matrix to the underlying physical origin using the physics-based approach. The calculated MM contour plots obtained from a biaxial Bruggemann effective medium approximation model are completed by the presence of Rayleigh-Woods anomalies. The roles of optical interference, geometric anisotropy, and diffraction orders are respectively identified by their different dispersion behavior, with their interactions and couplings highlighted. Such a straightforward procedure provides a new method for analyzing dielectric gratings, which requires considerably less computer power and is directly linked to the physical interpretations.
Strong localization effects in the photoluminescence of transition metal dichalcogenide heterobilayers
Authors: Rodriguez A , Kalbáč M , Frank O
Published: February 2021

The emergence of various exciton-related effects in transition metal dichalcogenides (TMDC) and their heterostructures has inspired a significant number of studies and brought forth several possible applications. Often, standard photoluminescence (PL) with microscale lateral resolution is utilized to identify and characterize these excitonic phenomena, including interlayer excitons (IEXs). We studied the local PL signatures of van der Waals heterobilayers composed of exfoliated monolayers of the (Mo, W)(S, Se)2 TMDC family with high spatial resolution (down to 30 nm) using tip-enhanced photoluminescence (TEPL) with different orders (top/bottom) and on different substrates. We evidence that in MoS2–WSe2 heterobilayers, other PL signals may appear near the reported energy of the IEX transitions, possibly interfering in the interpretation of the results. The extra signals are only observed locally in small areas where the topography looks distorted. We assign those signals to the PL of the individual monolayers, in which the exciton energy is altered by the local strains caused by the formation of blisters and nanobubbles, and the PL is extremely enhanced due to the decoupling of the layers. We prove that even a single nanobubble as small as 60 nm—hence not optically visible—can induce such a suspicious PL feature in the micro-PL spectrum of an otherwise flat heterobilayer. In contrast, a PL peak, which could be assigned to the interlayer exciton in MoS2–WSe2, is observed at ≈1.0 eV.
Understanding the beneficial microalloying elements in Fe-based bulk metallic glasses via clusters
Authors: Yu DeChuan , Zhang YuanXiang , Li Xue , Yuan Guo
Published: February 2021

Glass forming ability (GFA) is one of the key factors hindering the application of bulk metallic glasses (BMGs). Microalloying has shown beneficial effects on GFA. However, the mechanism is still unclear. A new guidance via clusters was applied to understand and quickly choose beneficial microalloying elements for enhancing GFA which might help build a foundation for further quantitative analysis of minor alloying via clusters. Under the guidance, a series of beneficial microalloying elements could be quickly discovered, verified and understood. The results show that the beneficial microalloying elements for enhancing GFA should be chosen under the condition of bringing in new types of topologically efficiently packed clusters.
Experimental investigations on fatigue life enhancement of composite (e-glass/epoxy) single lap joint with graphene oxide modified adhesive
Authors: Ghadge Rohit R , Prakash S , Ganorkar Shaunak A
Published: February 2021

With the increased use of composites in various sectors as a lightweight material exhibits high strength to weight ratio with tailor made properties. It becomes necessary to focus on various joining methods and different types of composite joints and their strength. The present study aims to improve the mechanical strength of single lap joint of composite material comprises of E-glass fibers and nano modified adhesive. Epoxy adhesive has been modified by dispersing Graphene Oxide (GO) to investigate the possibility of enhancement in the fatigue strength and fracture resistance of the single lap joint. Modified Hummer’s method has been used for synthesis of Graphene Oxide. Experimental investigations have been carried out for comparison of tensile and fatigue strength which shows significant improvement in the number of failure cycles for 0.25 wt.% and 0.75 wt.% GO concentrations respectively as compared to neat adhesive. Tension test results showed a significant increase in the fracture toughness of the joint due to addition of GO nanoparticles. There has been 33% and 19% increase in fracture toughness in 0.25 wt.% and 0.75 wt.% GO samples respectively as compared to neat adhesive. Improvement in fracture toughness, among all other nano-reinforcements has been obtained using GO, mainly because of its better capability of deviating the crack growth path to the longer path causing the final failure to retard and consequently improving mechanical properties of the adhesive for the tensile and fatigue strength parameters.
Examining the impact of inter-provincial migration on environmental health in China
Authors: Yang Yu-Ou , Hou Juan-Juan , Chen Xin-Yu , Yu Shi-Wei , Zhang Jiu-Tian , Liu Lan-Cui
Published: February 2021

China has a large volume of inter-provincial migrants, accounting for more than 11% of the total population. The economic benefits of inter-provincial migration have been well studied, whereas the health impacts related to environmental factors are generally ignored. In this study, the exposure-response function was used to estimate the health effects and the corresponding economic value was calculated by the adjusted-human-capital and cost-of-illness methods. Considering a scenario without personal protection, inter-provincial migration resulted in a reduction of 6114 premature deaths, 233.4 thousand hospitalization cases, and 1.5 million asthma attacks due to the PM2.5 population-weighted exposure decreasing by 3.94 μg m−3 in 2015. The avoided economic value of these health benefits was 0.02% of the national GDP in 2015. However, two-fifths of inter-provincial migrants whose destinations are areas with heavier pollution suffered greater health losses at the regional level. Additionally, personal protection does not significantly reduce the health loss. Thus, national pollution control measures are required to curb air pollution.
Revving up 13C NMR shielding predictions across chemical space: benchmarks for atoms-in-molecules kernel machine learning with new data for 134 kilo molecules
Authors: Gupta Amit , Chakraborty Sabyasachi , Ramakrishnan Raghunathan
Published: February 2021

The requirement for accelerated and quantitatively accurate screening of nuclear magnetic resonance spectra across the small molecules chemical compound space is two-fold: (1) a robust ‘local’ machine learning (ML) strategy capturing the effect of the neighborhood on an atom’s ‘near-sighted’ property—chemical shielding; (2) an accurate reference dataset generated with a state-of-the-art first-principles method for training. Herein we report the QM9-NMR dataset comprising isotropic shielding of over 0.8 million C atoms in 134k molecules of the QM9 dataset in gas and five common solvent phases. Using these data for training, we present benchmark results for the prediction transferability of kernel-ridge regression models with popular local descriptors. Our best model, trained on 100k samples, accurately predicts isotropic shielding of 50k ‘hold-out’ atoms with a mean error of less than 1.9 ppm. For the rapid prediction of new query molecules, the models were trained on geometries from an inexpensive theory. Furthermore, by using a Δ-ML strategy, we quench the error below 1.4 ppm. Finally, we test the transferability on non-trivial benchmark sets that include benchmark molecules comprising 10–17 heavy atoms and drugs.
Conformable fractional Hermite-Hadamard type inequalities for product of two harmonic 𝑠-convex functions
Authors: Meftah B. , Benssaad M. , Kaidouchi W. , Ghomrani S.
Published: February 2021

In this paper, we establish some conformable fractional Hermite-Hadamard type integral inequalities via harmonic

s
s

-convexity, and the estimates of the products of two harmonic

s
s

-convex functions are also considered.
Biases in Evaluating the Safety and Effectiveness of Drugs for the Treatment of COVID-19: Designing Real-World Evidence Studies
Authors: Renoux Christel , Azoulay Laurent , Suissa Samy
Published: February 2021

The coronavirus disease 2019 pandemic, which was caused by the severe acute respiratory syndrome coronavirus 2, has led to an unprecedented effort to generate real-world evidence on the safety and effectiveness of various treatments. A growing number of observational studies in which the effects of certain drugs were evaluated have been conducted, including several in which researchers assessed whether hydroxychloroquine improved outcomes in infected individuals and whether renin-angiotensin-aldosterone system inhibitors have detrimental effects. In the present article, we review and illustrate how immortal time bias and selection bias were present in several of these studies. Understanding these biases and how they can be avoided may prove important for future observational studies assessing the effectiveness and safety of potentially promising drugs during the coronavirus 19 pandemic.