bluuebunny/crossref_metadata_2025 huggingface dataset:
An efficient hybrid scheme for time dependent density functional theory
Authors: Medves Marco , Sementa Luca , Toffoli Daniele , Fronzoni Giovanna , Fortunelli Alessandro , Stener Mauro
Published: May 2020

A hybrid approach able to perform Time Dependent Density Functional Theory (TDDFT) simulations with the same accuracy as that of hybrid exchange-correlation (xc-) functionals but at a fraction of the computational cost is developed, implemented, and validated. The scheme, which we name Hybrid Diagonal Approximation (HDA), consists in employing in the response function a hybrid xc-functional (containing a fraction of the non-local Hartree–Fock exchange) only for the diagonal elements of the omega matrix, while the adiabatic local density approximation is employed for the off-diagonal terms. HDA is especially (but not exclusively) advantageous when using Slater type orbital basis sets and allows one to employ them in a uniquely efficient way, as we demonstrate here by implementing HDA in a local version of the Amsterdam Density Functional code. The new protocol is tested on NH3, C6H6, and the [Au25(SCH3)18]− cluster as prototypical cases ranging from small molecules to ligand-protected metal clusters, finding excellent agreement with respect to both full kernel TDDFT simulations and experimental data. Additionally, a specific comparison test between full kernel and HDA is considered at the Casida level on seven other molecular species, which further confirm the accuracy of the approach for all investigated systems. For the [Au25(SCH3)18]− cluster, a speedup by a factor of seven is obtained with respect to the full kernel. The HDA, therefore, promises to provide a quantitative description of the optical properties of medium-sized systems (nanoclusters) at an affordable cost, thanks to its computational efficiency, especially in combination with a complex polarization algorithm version of TDDFT.
A versatile molecular beam apparatus for cold/ultracold collisions
Authors: Amarasinghe Chandika , Perera Chatura A. , Suits Arthur G.
Published: May 2020

We have developed an apparatus capable of performing intrabeam and near-copropagating beam scattering experiments at collision energies from room temperature to below 1 K where interesting quantum phenomena can be observed. A detailed description of the major components of the apparatus, single and dual molecular beam valves, high speed chopper, and the discharge source, is presented. With the intrabeam scattering setup, a novel dual-slit chopper permits collision energies down to millikelvins with a collision energy spread of 20%. With the near-copropagating beam configuration, state-to-state differential cross sections for rotationally inelastic collisions of highly vibrationally excited NO molecules with Ar have been measured at broadly tunable energies documenting the versatility of the instrument. Future applications in stereodynamics and cold state-to-state collisions of vibrationally excited polyatomic molecules are briefly discussed.
Tunable superconductivity of epitaxial TiN films through oxygen doping
Authors: Peng Shaoqin , Zhang Ruyi , Song Yang , Pei Yujuan , Bi Jiachang , Feng Jiagui , Tang Minghua , Cao Yanwei
Published: May 2020

Titanium nitride (TiN) film is a remarkable material for a variety of applications ranging from superhard coating to superconducting quantum devices, which can be easily oxidized when it works in the atmosphere. However, the study of its oxidation effect on the crystal and electronic structures of epitaxial TiN films is rare as yet. Here, we coherently synthesize TiN epitaxial films on MgO single crystal substrates via reactive magnetron sputtering and, then, dope oxygen into these films via a controllable oxidation process. The crystal and electronic structures are characterized by high-resolution x-ray diffraction, x-ray photoelectron spectra, and Raman spectra. It is revealed that the crystal structure remains to be of the rocksalt type in these films even with heavy oxygen doping. The data of temperature-dependent electrical transport measurements indicate that the superconducting critical temperature (kinetic inductance) decreases (increases) from 4.6 K (0.672 pH/□) in the pristine TiN film to 3.4 K (1.13 pH/□) in the film with a maximum oxygen doping level. Our work provides a controllable way to tune the superconductivity of TiN films, which enables the flexibility to engineer the resultant performance of TiN-based superconducting quantum devices.
Increased drought severity tracks warming in the United States’ largest river basin
Authors: Martin Justin T. , Pederson Gregory T. , Woodhouse Connie A. , Cook Edward R. , McCabe Gregory J. , Anchukaitis Kevin J. , Wise Erika K. , Erger Patrick J. , Dolan Larry , McGuire Marketa , Gangopadhyay Subhrendu , Chase Katherine J. , Littell Jeremy S. , Gray Stephen T. , St. George Scott , Friedman Jonathan M. , Sauchyn David J. , St-Jacques Jeannine-Marie , King John
Published: May 2020

Across the Upper Missouri River Basin, the recent drought of 2000 to 2010, known as the “turn-of-the-century drought,” was likely more severe than any in the instrumental record including the Dust Bowl drought. However, until now, adequate proxy records needed to better understand this event with regard to long-term variability have been lacking. Here we examine 1,200 y of streamflow from a network of 17 new tree-ring–based reconstructions for gages across the upper Missouri basin and an independent reconstruction of warm-season regional temperature in order to place the recent drought in a long-term climate context. We find that temperature has increasingly influenced the severity of drought events by decreasing runoff efficiency in the basin since the late 20th century (1980s) onward. The occurrence of extreme heat, higher evapotranspiration, and associated low-flow conditions across the basin has increased substantially over the 20th and 21st centuries, and recent warming aligns with increasing drought severities that rival or exceed any estimated over the last 12 centuries. Future warming is anticipated to cause increasingly severe droughts by enhancing water deficits that could prove challenging for water management.
TDP-43 dysfunction restricts dendritic complexity by inhibiting CREB activation and altering gene expression
Authors: Herzog Josiah J. , Xu Weijin , Deshpande Mugdha , Rahman Reazur , Suib Hannah , Rodal Avital A. , Rosbash Michael , Paradis Suzanne
Published: May 2020

Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are two related neurodegenerative diseases that present with similar TDP-43 pathology in patient tissue. TDP-43 is an RNA-binding protein which forms aggregates in neurons of ALS and FTD patients as well as in a subset of patients diagnosed with other neurodegenerative diseases. Despite our understanding that TDP-43 is essential for many aspects of RNA metabolism, it remains obscure how TDP-43 dysfunction contributes to neurodegeneration. Interestingly, altered neuronal dendritic morphology is a common theme among several neurological disorders and is thought to precede neurodegeneration. We previously found that both TDP-43 overexpression (OE) and knockdown (KD) result in reduced dendritic branching of cortical neurons. In this study, we used TRIBE (targets of RNA-binding proteins identified by editing) as an approach to identify signaling pathways that regulate dendritic branching downstream of TDP-43. We found that TDP-43 RNA targets are enriched for pathways that signal to the CREB transcription factor. We further found that TDP-43 dysfunction inhibits CREB activation and CREB transcriptional output, and restoring CREB signaling rescues defects in dendritic branching. Finally, we demonstrate, using RNA sequencing, that TDP-43 OE and KD cause similar changes in the abundance of specific messenger RNAs, consistent with their ability to produce similar morphological defects. Our data therefore provide a mechanism by which TDP-43 dysfunction interferes with dendritic branching, and may define pathways for therapeutic intervention in neurodegenerative diseases.
Retinal capillary oximetry with visible light optical coherence tomography
Authors: Pi Shaohua , Hormel Tristan T. , Wei Xiang , Cepurna William , Wang Bingjie , Morrison John C. , Jia Yali
Published: May 2020

Assessing oxygen saturation (sO
2
) remains challenging but is nonetheless necessary for understanding retinal metabolism. We and others previously achieved oximetry on major retinal vessels and measured the total retinal oxygen metabolic rate in rats using visible-light optical coherence tomography. Here we extend oximetry measurements to capillaries and investigate all three retinal vascular plexuses by amplifying and extracting the spectroscopic signal from each capillary segment under the guidance of optical coherence tomography (OCT) angiography. Using this approach, we measured capillary sO
2
in the retinal circulation in rats, demonstrated reproducibility of the results, validated the measurements in superficial capillaries with known perfusion pathways, and determined sO
2
responses to hypoxia and hyperoxia in the different retinal capillary beds. OCT capillary oximetry has the potential to provide new insights into the retinal circulation in the normal eye as well as in retinal vascular diseases.
Mortality and risk of progression to adult T cell leukemia/lymphoma in HTLV-1–associated myelopathy/tropical spastic paraparesis
Authors: Nagasaka Misako , Yamagishi Makoto , Yagishita Naoko , Araya Natsumi , Kobayashi Seiichiro , Makiyama Junya , Kubokawa Miyuki , Yamauchi Junji , Hasegawa Daisuke , Coler-Reilly Ariella L. G. , Tsutsumi Shuntaro , Uemura Yu , Arai Ayako , Takata Ayako , Inoue Eisuke , Hasegawa Yasuhiro , Watanabe Toshiki , Suzuki Yutaka , Uchimaru Kaoru , Sato Tomoo , Yamano Yoshihisa
Published: May 2020

Human T cell leukemia virus 1 (HTLV-1) causes the functionally debilitating disease HTLV-1–associated myelopathy/tropical spastic paraparesis (HAM/TSP) as well as adult T cell leukemia lymphoma (ATLL). Although there were concerns that the mortality of HAM/TSP could be affected by the development of ATLL, prospective evidence was lacking in this area. In this 5-y prospective cohort study, we determined the mortality, prevalence, and incidence of ATLL in 527 HAM/TSP patients. The standard mortality ratio of HAM/TSP patients was 2.25, and ATLL was one of the major causes of death (5/33 deaths). ATLL prevalence and incidence in these patients were 3.0% and 3.81 per 1,000 person-y, respectively. To identify patients at a high risk of developing ATLL, flow cytometry, Southern blotting, and targeted sequencing data were analyzed in a separate cohort of 218 HAM/TSP patients. In 17% of the HAM/TSP patients, we identified an increase in T cells positive for cell adhesion molecule 1 (CADM1), a marker for ATLL and HTLV-1–infected cells. Genomic analysis revealed that somatic mutations of HTLV-1–infected cells were seen in 90% of these cases and 11% of them had dominant clone and developed ATLL in the longitudinal observation. In this study, we were able to demonstrate the increased mortality in patients with HAM/TSP and a significant effect of ATLL on their prognosis. Having dominant clonal expansion of HTLV-1–infected cells with ATLL-associated somatic mutations may be important characteristics of patients with HAM/TSP who are at an increased risk of developing ATLL.
Evidence for sodium-rich alkaline water in the Tagish Lake parent body and implications for amino acid synthesis and racemization
Authors: White Lee F. , Tait Kimberly T. , Langelier Brian , Lymer Elizabeth A. , Černok Ana , Kizovski Tanya V. , Ma Chi , Tschauner Oliver , Nicklin Richard I.
Published: May 2020

Understanding the timing and mechanisms of amino acid synthesis and racemization on asteroidal parent bodies is key to demonstrating how amino acids evolved to be mostly left-handed in living organisms on Earth. It has been postulated that racemization can occur rapidly dependent on several factors, including the pH of the aqueous solution. Here, we conduct nanoscale geochemical analysis of a framboidal magnetite grain within the Tagish Lake carbonaceous chondrite to demonstrate that the interlocking crystal arrangement formed within a sodium-rich, alkaline fluid environment. Notably, we report on the discovery of Na-enriched subgrain boundaries and nanometer-scale Ca and Mg layers surrounding individual framboids. These interstitial coatings would yield a surface charge state of zero in more-alkaline fluids and prevent assimilation of the individual framboids into a single grain. This basic solution would support rapid synthesis and racemization rates on the order of years, suggesting that the low abundances of amino acids in Tagish Lake cannot be ascribed to fluid chemistry.
Phalangeal curvature in a chimpanzee raised like a human: Implications for inferring arboreality in fossil hominins
Authors: Wallace Ian J. , Burgess M. Loring , Patel Biren A.
Published: May 2020

Arboreal primates such as chimpanzees exhibit pronounced curvature in their hand and foot phalanges, which is assumed to develop throughout life in response to mechanical loads produced by grasping and hanging from branches. Intriguingly, ancient fossil hominins also exhibit substantial phalangeal curvature, which, too, has been interpreted as a direct result of habitual arboreality during life. Here, we describe the phalangeal curvature of a chimpanzee who was raised during the 1930s in New York City to live much like a human, including by having very few opportunities to engage in arboreal activities. We show that the degree of hand and foot phalangeal curvature in this individual is indistinguishable from that of wild chimpanzees and distinct from humans. Thus, rather than being a direct effect of mechanical loads produced by lifetime arboreal activities, phalangeal curvature appears to be shaped largely by genetic factors. An important implication of this finding is that phalangeal curvature among fossil hominins is evidently best interpreted as a primitive trait inherited from an arboreal ancestral species rather than proof of engagement in arboreal activities during life.
Swearwords reinterpreted
Authors: Li Bin , Dou Yan , Cui Yingting , Sheng Yuqi
Published: May 2020

Swearwords are common on the Internet nowadays. In addition to traditional forms and functions, new features and
uses have been created as disguises and hedges, or even as deviants from insults. Focusing on the ‘new swearwords’ prevalent in
Chinese social media, we identified the most commonly used novel swearwords developed and favoured by the young Chinese netizens,
and analysed their linguistic features and uses on a Chinese social network site. We discovered that certain swearwords have
undergone linguistic transformation to take up new grammatical and pragmatic functions. The invention and prevalence of these new
swearwords raise interesting points on the roles played by the Internet and social media in bringing netizens together and in
enabling them to create web content in their speech community.
Impact of sedentarism due to the COVID‐19 home confinement on neuromuscular, cardiovascular and metabolic health: Physiological and pathophysiological implications and recommendations for physical and nutritional countermeasures
Authors: Narici Marco , Vito Giuseppe De , Franchi Martino , Paoli Antonio , Moro Tatiana , Marcolin Giuseppe , Grassi Bruno , Baldassarre Giovanni , Zuccarelli Lucrezia , Biolo Gianni , di Girolamo Filippo Giorgio , Fiotti Nicola , Dela Flemming , Greenhaff Paul , Maganaris Constantinos
Published: May 2020

The COVID‐19 pandemic is an unprecedented health crisis as entire populations have been asked to self‐isolate and live in home‐confinement for several weeks to months, which in itself represents a physiological challenge with significant health risks. This paper describes the impact of sedentarism on the human body at the level of the muscular, cardiovascular, metabolic, endocrine and nervous systems and is based on evidence from several models of inactivity, including bed rest, unilateral limb suspension, and step‐reduction. Data form these studies show that muscle wasting occurs rapidly, being detectable within two days of inactivity. This loss of muscle mass is associated with fibre denervation, neuromuscular junction damage and upregulation of protein breakdown, but is mostly explained by the suppression of muscle protein synthesis. Inactivity also affects glucose homeostasis as just few days of step reduction or bed rest, reduce insulin sensitivity, principally in muscle. Additionally, aerobic capacity is impaired at all levels of the O2 cascade, from the cardiovascular system, including peripheral circulation, to skeletal muscle oxidative function. Positive energy balance during physical inactivity is associated with fat deposition, associated with systemic inflammation and activation of antioxidant defences, exacerbating muscle loss. Importantly, these deleterious effects of inactivity can be diminished by routine exercise practice, but the exercise dose–response relationship is currently unknown. Nevertheless, low to medium‐intensity high volume resistive exercise, easily implementable in home‐settings, will have positive effects, particularly if combined with a 15–25% reduction in daily energy intake. This combined regimen seems ideal for preserving neuromuscular, metabolic and cardiovascular health.
A Direct Derivation of the Dark Soliton Excitation Energy*
Authors: Zhao Li-Chen , Qin Yan-Hong , Wang Wen-Long , Yang Zhan-Ying
Published: May 2020

Dark solitons are common topological excitations in a wide array of nonlinear waves. The dark soliton excitation energy is crucial for exploring dark soliton dynamics and is necessarily calculated in a renormalized form due to its existence on a finite background. Despite its tremendous importance and success, the renormalized energy form was at first only suggested with no detailed derivation, and was then “derived” in the grand canonical ensemble. We revisit this fundamental problem and provide an alternative and intuitive derivation of the energy form from the fundamental field energy by utilizing a limiting procedure that conserves number of particles. Our derivation yields the same result, thus putting the dark soliton energy form on a solid basis.
Approach to Single-Mode Dominated Resonant Emission in GaN-Based Square Microdisks on Si*
Authors: Liu Meng-Han , Chen Peng , Xie Zi-Li , Xiu Xiang-Qian , Chen Dun-Jun , Liu Bin , Han Ping , Shi Yi , Zhang Rong , Zheng You-Dou , Cheng Kai , Zhang Li-Yang
Published: May 2020

Square microdisks with round corners are fabricated using a standard GaN-based blue LED on Si substrates. Whispering gallery-like modes in the square microdisks are investigated by finite-difference time-domain simulation. The simulation results reveal that the round corners in square microdisks can substantially suppress the number of light propagation paths and further reduce the number of optical modes. A confocal micro-photoluminescence is performed to analyze the optical properties of the square microdisks at room temperature. The single-mode dominant resonant emission is obtained in the square microdisk with corner radius of 1.5 μm.
Three-Dimensional Broadband Acoustic Waveguide Cloak*
Authors: Hu Chuan-Jie , Zeng Ya-Li , Liu Yi-Neng , Chen Huan-Yang
Published: May 2020

The propagation of acoustic waves is a fundamental topic in shallow ocean acoustics. We numerically demonstrate a three-dimensional zone of silence consisting of a circular tube with gradient index metamaterials attached to its rigid wall. The cloaking effect is verified by fine agreement with analytical calculations.
Simulation of the Weakly Nonlinear Rayleigh-Taylor Instability in Spherical Geometry*
Authors: Yang Yun-Peng , Zhang Jing , Li Zhi-Yuan , Wang Li-Feng , Wu Jun-Feng , Ye Wen-Hua , He Xian-Tu
Published: May 2020

The Rayleigh–Taylor instability at the weakly nonlinear (WN) stage in spherical geometry is studied by numerical simulation. The mode coupling processes are revealed. The results are consistent with the WN model based on parameter expansion, while higher order effects are found to be non-negligible. For Legendre mode perturbation Pn
(cosθ), the nonlinear saturation amplitude (NSA) of the fundamental mode decreases with the mode number n. When n is large, the spherical NSA is lower than the corresponding planar one. However, for large n, the planar NSA can be recovered by applying Fourier transformation to the bubble/spike near the equator and calculating the NSA of the converted trigonometric harmonic.
Structural Transition from Ordered to Disordered of BeZnO2 Alloy*
Authors: Qin Li-Xia , Liang Han-Pu , Jiang Rong-Li
Published: May 2020

Employing Monte Carlo simulations based on the cluster expansion, the special quasi-random structures and first-principles calculations, we systematically investigate the structure transition of BeZnO2 alloys from the ordered to the disordered phase driven by the increased synthesis temperature, together with the solid-state phase diagram. It is found that by controlling the ordering parameter at the mixed sublattice, the band structure can vary continuously from a wide direct band gap of 4.61 eV for the fully ordered structure to a relatively narrow direct band gap of 3.60 eV for the fully disordered structure. Therefore, a better optical performance could be achieved simply by controlling the synthesis temperature, which determines the ordering parameters and thus the band gaps.
Origin of Anisotropy in Gadolinium Crystal Using a New Spin Hamiltonian*
Authors: Wei Dan , Chen Zhibin , Yang Hui , Cao Yongjun , Liu Chuan
Published: May 2020

Single crystal rare-earth magnets, such as hexagonal-close-packed gadolinium, usually have a large second order anisotropy K
2 and a negative first order anisotropy K
1 at low temperatures, which are difficult to explain using microscopic theories. An atomic scale effective spin Hamiltonian ℱ[{
S
i
}] is proposed, which, apart from the usual isotropic nearest neighbor coupling J, consists of two new terms that are different for in-plane and out-of-plane neighbors and which are characterized by two new couplings C
1 and C
2, respectively. The hybrid Monte–Carlo method is utilized to sample this system to the desired Boltzmann-like distribution exp(−ℱ/k
B
T). It is found that K
2 and K
1 are compatible with the experimental values and arise naturally from the exchange anisotropy C
1 and C
2, which are less than 0.01 in magnitude of the isotropic exchange energy J. This new model spin Hamiltonian can also be applied to study other magnetic properties.
Ultrafine Mo-Doped Co2P Nanorods Anchored on Reduced Graphene Oxide as Efficient Electrocatalyst for the Hydrogen Evolution Reaction*
Authors: Wang Yi-Xuan , Yang Qing , Liu Chuang , Wang Guang-Xia , Wu Min , Liu Hao , Sui Yong-Ming , Yang Xin-Yi
Published: May 2020

One-dimensional (1D) transition metal phosphides (TMPs) with large specific surface areas, high charge transfer efficiency and excellent electrical conductivity have attracted significant attention in hydrogen evolution reaction (HER) as versatile and active catalysts. Herein, the sub-4 nm Mo-Co
2
P ultrafine nanorods (NRs) anchored on reduced graphene oxide (rGO) were successfully synthesized by a colloidal mesostructured strategy. Electrochemical test results reveal that the Mo-Co
2
P@rGO electrode exhibits superior activity with overpotentials of 204 mV and Tafel slope of 88 mV/dec for HER at 10 mA/cm
2
, relative to the Co
2
P@rGO electrode in 0.5 M H
2
SO
4
solution. This improvement could be ascribed to the Mo doping, which results in more active sites, higher electrical conductivity and faster electron-transfer rates. This versatile strategy will provide a promising pathway for transition metal-doped compounds as an efficient catalyst.
Rapid Structure-Based Screening Informs Potential Agents for Coronavirus Disease (COVID-19) Outbreak*
Authors: Yang Zhi-Wei , Zhao Yi-Zhen , Zang Yong-Jian , Wang He , Zhu Xun , Meng Ling-Jie , Yuan Xiao-Hui , Zhang Lei , Zhang Sheng-Li
Published: May 2020

Coronavirus Disease 2019 (COVID-19), caused by the novel coronavirus, has spread rapidly across China. Consequently, there is an urgent need to sort and develop novel agents for the prevention and treatment of viral infections. A rapid structure-based virtual screening is used for the evaluation of current commercial drugs, with structures of human angiotensin converting enzyme II (ACE2), and viral main protease, spike, envelope, membrane and nucleocapsid proteins. Our results reveal that the reported drugs Arbidol, Chloroquine and Remdesivir may hinder the entry and release of virions through the bindings with ACE2, spike and envelope proteins. Due to the similar binding patterns, NHC (β-d-N4-hydroxycytidine) and Triazavirin are also in prospects for clinical use. Main protease (3CLpro) is likely to be a feasible target of drug design. The screening results to target 3CL-pro reveal that Mitoguazone, Metformin, Biguanide Hydrochloride, Gallic acid, Caffeic acid, Sulfaguanidine and Acetylcysteine seem be possible inhibitors and have potential application in the clinical therapy of COVID-19.
Oscillations due to time-delayed driving of a ball in a water jet—a challenging problem of the International Physicists’ Tournament 2019
Authors: Michalke S , Fösel A , Schmiedeberg M
Published: May 2020

The International Physicists’ Tournament (IPT) 2019 dealt with 17 challenging problems. In this article, we present experimental as well as theoretical approaches as examples of one of these tasks. A ball placed on a hard and flat surface can oscillate when being hit by a jet of water from above. To explain the oscillations, a theoretical model is introduced and its predictions are compared to experimental measurements. Furthermore, the structure of the IPT itself is characterized briefly in this article, as well as the idea of a new and innovative seminar, which was set up at Erlangen University to prepare and assist students in taking part in the IPT. Furthermore, the educational relevance of physics tournaments such as IPT for physics education at university is discussed in detail.
Radial control of electron temperature gradient with optimized operational configuration of double plasma device
Authors: Alex Prince , Sanyasi A K , Srivastav Prabhakar , Awasthi L M , Srivastava P K , Sugandhi Ritesh
Published: May 2020

A double plasma device (DPD) is tested for different operational configurations to identify suitable control for plasma parameters in a weakly ionized, unmagnetized plasma discharge. A separation grid is installed between the two chambers of DPD, which allows filtering of plasma from the first to the second chamber. Investigations are carried out to control the plasma parameters, especially the electron temperature by exploring the role of the grid. The grid bias is varied between −25–0 V and 0–30 V to reflect cooling and heating of plasma. The electron heating and cooling is prominent for the maximum ratio of n
source/n
target. The electron energy distribution function (EEDF) is obtained to describe the role of grid biasing in controlling the electron temperature in the second chamber. We demonstrated control on the radial profile of electron temperature by charging different radial cross-sections of plasma differently by using a multi-grid assembly system (MGAS). We have also identified the suitable operational regime for DPD where exercising a radial control on electron temperature is possible. Such plasmas can facilitate investigations on electron temperature control for applications in plasma processing, cold–plasma material interaction, etc where low energy electrons are desired.
Femtosecond two-photon laser-induced fluorescence imaging of atomic hydrogen in a laminar methane–air flame assisted by nanosecond repetitively pulsed discharges
Authors: Cont-Bernard Davide Del , Ruchkina Maria , Ding Pengji , Bood Joakim , Ehn Andreas , Lacoste Deanna A
Published: May 2020

Sustainable and low-emission combustion is in need of novel schemes to enhance combustion efficiency and control to meet up with new emission standards and comply with varying quality of renewable fuels. Plasma actuation is a promising candidate to achieve this goal but few detailed experiments have been carried out that target how specific combustion and plasma related species are affected by the coupling of plasma and combustion chemistry. Atomic hydrogen is such a species that here is imaged by using the two-photon absorption laser induced fluorescence (TALIF) technique as an atmospheric pressure methane–air flame is actuated by nanosecond repetitively pulsed (NRP) discharges. Atomic hydrogen is observed both in the flame and in the discharge channel and plasma actuation results in a wide modification of the flame shape. A local 50% increase of fluorescence occurs at the flame front where it is crossed by the discharge. Atomic hydrogen in the discharge channel in the fresh-gases is found to decay with a time constant of about 2.4 μs. These results provide new insights on the plasma flame interaction at atmospheric pressure that can be further used for cross-validation of numerical calculations.
How to prestress compliant mechanisms for a targeted stiffness adjustment
Authors: Mauser Kristian , Hasse Alexander
Published: May 2020

The paper deals with compliant mechanisms with a variable stiffness behavior. Devices with such a behavior are getting more and more attention in recent years, especially in contact applications such as human-robotic-interactions or haptic interfaces. In the work presented here the variable stiffness behavior is achieved by the targeted application of prestressing forces. An optimization based method is presented to identify suitable force application points. Furthermore, the amount and direction of force is determined in order to cause a specific change in stiffness. The method consists of a convex optimization formulation and is based on modal parameters. The method is intended to work for any given design of a compliant mechanism. In this publication the method is tested and evaluated using two compliant mechanisms—the cartwheel hinge and a shape-adaptive airfoil profile.
The GAPS experiment – a search for cosmic-ray antinuclei from dark matter
Authors: Kozai Masayoshi
Published: May 2020

The General Antiparticle Spectrometer (GAPS) is a balloon-borne experiment that aims to study low-energy cosmic-ray antinuclei. A novel detection concept that utilizes the physics of exotic atoms allows GAPS to realize a large sensitive area, a low energy threshold, and a high identification capability for antinuclei. The primary goal is to search for antideuterons in the energy region <0.25 GeV/n, where they are predicted to be backgroundfree probes for dark matter-annihilation or decay in the Galactic halo. GAPS will also measure precise low-energy antiproton spectra, which provide crucial information about the source and propagation of cosmic rays. Three flights on long-duration balloons from Antarctica are planned; the first flight of GAPS is scheduled for late 2021. This paper presents the scientific motivation, detection concept, development status, and plans for GAPS.
Development of Aid Tool using Arduino Uno Sensor for Dynamic Fluid at Senior High School
Authors: Herdayanti A , Rahmatsyah  , Manurung S R
Published: May 2020

The purpose of this research is to develop dynamic fluid teaching aids for senior high school. Visualized aid tool based on dynamic fluid material. The methods used in research are the ADDIE development model (analyze, design, development, implementation and evaluation). This device was designed using the Arduino UNO sensor that can be connected to the sensor, the water flow sensor serves as a discharge meter, the LCD display screen serves the result of the calculation of the water flow sensor, the sensors water work so that water is not abundant in the container, and feeding as on/off. There is a certain height of water faucet that can make the students adjust the height that will be calculated flow discharge, the difference in the height of the stream on the venturimeter and the difference in gas pressure in the pitot tubes. The aid tool also have a worksheet for students. Based on the result of expert validation of aid tool is 86% and the validation of material experts on the student’s worksheet is 94% and efficiency on learning is 88%. The overall result of the expert validation test gets a good rating so the development of aid tool using the Arduino uno sensor and water flow sensor for dynamic fluid.
Analysis of Problem Solving Ability Tests on Dynamics Material in Basic Physics Courses
Authors: Hutapea Jonathan , Sahyar Sahyar , Manurung Sondang R
Published: May 2020

This research aims to construct the problem solving ability test questions on basic physical dynamics material according to standards of good test qualifications in terms of validity, reliability, difficulty index and discrimination index. This type of research is development research using research and development methods of Borg and Gall model. The sample in this study were all semester 2 students physics education program of Medan state university. The results of this research indicate that of the 40 questions developed, 14 questions have met the criteria of good questions based on theoretical and empirical analysis. The fourteen questions can be used to measure the ability to solve problems with basic competence to provide solutions to the, (1) material moment of force, (2) moment of inertia, (3) equilibrium, (4) centre of gravity, (5) the law of conservation of angular momentum and (6) the application of Newtons law..
Effect of Sarang Banua (ClerodendrumfragransVent Willd) Leaves Extract on Serum Globulin Levels of Rabbit (Oryctolagus cuniculus)
Authors: Simorangkir Murniaty , Nainggolan Bajoka , Doloksaribu Jeshica F , Silaban Saronom
Published: May 2020

Sarang banua plants are found in Simalungun, North Sumatra, Indonesia, which have been used by the community as traditional medicinal plants and is a type of ClerodendrumfragransVent Willd, including the family Verbanaceae. The study design was completely randomized design (CRD) with five treatments namely 1% Na-CMC (K1, negative control), bovine serum antigen (K2), ethanol extract of sarang banua leaf 200 mg/kg BW (K3), ethanol extract of sarang banua leaf 200 mg/kg BW with bovine serum antigen (K4) and ethanol extract of sarang banua leaf 150 mg/kg BW with bovine serum antigen (K5). The results showed that administration of ethanol extract of sarang banua leaf (ClerodendrumfragransVent Willd) significantly affected serum globulin levels of rabbits (Oryctolagus cuniculus). The ethanol extract of sarang banua leaves 200 mg/kg BW with bovine serum antigen (K4) produced the highest serum globulin levels of rabbits (12.91 mg/mL).
Experimental Video of Heat Transfer Science Based on Information Technology
Authors: Ramadhani Asiah , Sahyar Sahyar , Mulyana Rachmat
Published: May 2020

This research was conducted to produce an experimental video that is feasible and practical to use, to produce a scientific experiment video on heat transfer based on information technology. The development model used is an adaptation of the Borg & Gall model. The results of this study indicate the validation of material experts included in the feasible category, validation of media experts with very feasible categories, testing small groups with very practical categories and field trials with very practical categories.
The Effect of a combination of growing media and biological agents to control bacterial wilt disease of potato (Ralstoniasolanacearum) in greenhouse
Authors: Pinem Mukhtar Iskandar , Lubis Lahmuddin , Marheni  , Zuhdi Dedi Maradi
Published: May 2020

Potato (Solanumtuberosum L.) in Indonesia is a commodity that priorities todeveloped, and has the potential to be marketed in the domestic as well as export. One of the obstacles is important that faced is pathogen soil-borne which is caused by the Ralstoniasolanacearum. This pathogen can causing loss of yield of potato 40-100%. Bacillus sp. and Pseudemonas fluorescens are antagonistic microbes that are proven to be able to control bacterial wilt disease by 69,95 % and 61,67%. This study aimed to determine the effect of the comparison composition of growing media and the ability of some agents of biological within suppress the growth of the disease wilt bacteria of potatoes which is caused by R. solanacearum.This research using completely randomized design (CRD) nonfactorial with 10 treatments, namely: M0(top soil), M1(top soil, R. solanacearum), M2(top soil, R. solanacearum, P.fluorescens), M3(top soil, R. solanacearum, Bacillus subtilis), M4(top soil, Chicken manure, R. solanacearum, P.fluorescens), M5 until M9 are combination of them. The results showed that the application of biological agents was able to suppress the growth of the pathogen R. solanacearum, as well as significantly affect plant height, number of shoots, and production.
Analysis of Clam Hill Site in Aceh Tamiang Using Geo-electric Method
Authors: Rahmatsyah  , Juliani Rita , Hutahean Juniar
Published: May 2020

The clam hill site is a prehistoric relic which is a pile of million pieces of shells. Disclosure of the fact the formation of the clam site is essential to study. The purpose of this research is to analyze the subsurface area of the Clam Site in Aceh Tamiang. The Wenner-Schlumberger as a type geo-electric method is used in this research which contains six passes. The length of the track is 155 m using 32 electrodes with a distance between the electrodes 5 m. Res2Dinv Software and Surfer 11 software are used to process the geo-electric data. The results of the analysis obtain the resistivity value of the pile of the shell is between 19,5 Ωm to 4768 Ωm which is different from the surrounding resistivity of 0 to 29.800 Ωm. The surrounding site is dominated by beach and river surface deposits in the form of clay, sand, and gravel with low soil and rock carrying capacity. According to archaeology, heaps of shells come from the remnants of ancient human civilization in Aceh Tamiang.
The Constrains of Green Building Implementation in Indonesia
Authors: Sahid  , Sumiyati Y , Purisari R
Published: May 2020

Various success evidence of green building to save energy usage and reduce environmental impacts has been widely shared in various scientific and popular media. The information is not merely theoretical but also practical, include information about the addition of investment value, savings and profit earned on the operation stage. The government and the private sector have also encouraged the acceleration of its implementation through the establishment of regulations and rating tools that accomodateresponsibility for property industry actors to participate in implementing green building concepts. This study aims to find out the obstacles of green building implementation in Indonesia through literature review, policy review and also interviews to stake holders. Apparently, efforts are still needed to complete the various regulations needed for stakeholders to implement the concept of green buildings in all parts of the building’s life cycle.
Integration of Physics Concepts in Javanese Culture
Authors: Wijaya Hidayati , Derlina
Published: May 2020

The purpose of this article is to find out the integration of physics concepts in Javanese culture. Physics is very closely related to daily life. In the daily life of Javanese culture there are many concepts related to physics. The environment of traditional Javanese society always believes in ancestral messages and customs about how to behave and apply to nature. Various problem solving continues to be associated with science and technology for the growth, development and welfare of human life. In this universe, everything can be explained with the help of science, especially physics. One distinctive feature of Javanese culture’s local wisdom is batik making which applies the concept of capillary physics.
Air pollution from wildfires and human health vulnerability in Alaskan communities under climate change
Authors: Woo Seung Hyun Lucia , Liu Jia Coco , Yue Xu , Mickley Loretta J , Bell Michelle L
Published: May 2020

Alaskan wildfires are becoming more frequent and severe, but very little is known regarding exposure to wildfire smoke, a risk factor for respiratory and cardiovascular illnesses. We estimated long-term, present-day and future exposure to wildfire-related fine particulate matter (PM2.5) across Alaska for the general population and subpopulations to assess vulnerability using observed data for the present day (1997–2010), modelled estimates for the present day (1997–2001), and modelled estimates for the future (2047–2051). First, we assessed wildfire-PM2.5 exposure by estimating monthly-average wildfire-specific PM2.5 levels across 1997–2010 for 158 Alaskan census tracts, using atmospheric transport modelling based on observed area-burned data. Second, we estimated changes in future (2047–2051) wildfire-PM2.5 exposure compared to the present-day (1997–2001) by estimating the monthly-average wildfire-specific PM2.5 levels for 29 boroughs/census areas (county-equivalent areas), under the Intergovernmental Panel on Climate Change (IPCC) A1B scenario from an ensemble of 13 climate models. Subpopulation risks for present and future exposure levels were estimated by summing area-weighted exposure levels utilizing the 2000 Census and State of Alaska’s population projections. We assessed vulnerability by several subpopulation characteristics (e.g. race/ethnicity, urbanicity). Wildfire-PM2.5 exposure levels during 1997–2010 were highest in interior Alaska during July. Among subpopulations, average summer (June-August) exposure levels for urban dwellers and African-American/Blacks were highest at 9.1 µg m−3 and 10 µg m−3, respectively. Estimated wildfire-PM2.5 varied by Native American tribe, ranging from average summer levels of 2.4 µg m−3 to 13 µg m−3 for Tlingit-Haida and Alaskan Athabascan tribes, respectively. Estimates indicate that by the mid-21st century, under climate change, almost all of Alaska could be exposed to increases of 100% or more in levels of wildfire-specific PM2.5 levels. Exposure to wildfire-PM2.5 likely presents a substantial public health burden in the present day for Alaska communities, with different impacts by subpopulation. Under climate change, wildfire smoke could pose an even greater public health risks for most Alaskans.
Constrained dynamics: generalized Lie symmetries, singular Lagrangians, and the passage to Hamiltonian mechanics
Authors: Speliotopoulos Achilles D
Published: May 2020

Guided by the symmetries of the Euler–Lagrange equations of motion, a study of the constrained dynamics of singular Lagrangians is presented. We find that these equations of motion admit a generalized Lie symmetry, and on the Lagrangian phase space the generators of this symmetry lie in the kernel of the Lagrangian two-form. Solutions of the energy equation—called second-order, Euler–Lagrange vector fields (SOELVFs)—with integral flows that have this symmetry are determined. Importantly, while second-order, Lagrangian vector fields are not such a solution, it is always possible to construct from them a SOELVF that is. We find that all SOELVFs are projectable to the Hamiltonian phase space, as are all the dynamical structures in the Lagrangian phase space needed for their evolution. In particular, the primary Hamiltonian constraints can be constructed from vectors that lie in the kernel of the Lagrangian two-form, and with this construction, we show that the Lagrangian constraint algorithm for the SOELVF is equivalent to the stability analysis of the total Hamiltonian. Importantly, the end result of this stability analysis gives a Hamiltonian vector field that is the projection of the SOELVF obtained from the Lagrangian constraint algorithm. The Lagrangian and Hamiltonian formulations of mechanics for singular Lagrangians are in this way equivalent.
Viscous conservation laws in 1D with measure initial data
Authors: Bank Miriam , Ben-Artzi Matania , Schonbek Maria
Published: May 2020

The one-dimensional viscous conservation law is considered on the whole line
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="u Subscript t Baseline plus f left-parenthesis u right-parenthesis Subscript x Baseline equals epsilon u Subscript x x Baseline comma left-parenthesis x comma t right-parenthesis element-of double-struck upper R times double-struck upper R Subscript plus Baseline overbar comma epsilon greater-than 0 comma">

u
t

+
f
(
u

)
x

=
ε

u

x
x

,

(
x
,
t
)
∈

R

×

R

+

¯

,

ε
>
0
,

\begin{equation*} u_t + f(u)_x=\varepsilon u_{xx},\quad (x,t)\in \mathbb {R}\times \overline {\mathbb {R}_{+}},\quad \varepsilon >0, \end{equation*}

subject to positive measure initial data.

The flux

f
∈

C
1

(

R

)

f\in C^1(\mathbb {R})

is assumed to satisfy a

p
−

p-

condition, a weak form of convexity. In particular, any flux of the form

f
(
u
)
=

∑

i
=
1

J

a
i

u

m
i

f(u)=\sum _{i=1}^Ja_iu^{m_i}

is admissible if

a
i

>
0
,

m
i

>
1
,

i
=
1
,
2
,
…
,
J
.

a_i>0,\,m_i>1,\,\,i=1,2,\ldots ,J.

The only case treated hitherto in the literature is

f
(
u
)
=

u
m

f(u)=u^m

[Arch. Rat. Mech. Anal. 124 (1993), pp. 43–65] and the initial data is a “single source”, namely, a multiple of the delta function. The corresponding solutions have been labeled as “source-type” and the treatment made substantial use of the special form of both the flux and the initial data.

In this paper existence and uniqueness of solutions is established. The method of proof relies on sharp decay estimates for the viscous Hamilton-Jacobi equation. Some estimates are independent of the viscosity coefficient, thus leading to new estimates for the (inviscid) hyperbolic conservation law.
Temporal Confounding in the Test-Negative Design
Authors: Dean Natalie E , Halloran M Elizabeth , Longini, Jr Ira M
Published: May 2020

In the test-negative design, routine testing at health-care facilities is leveraged to estimate the effectiveness of an intervention such as a vaccine. The odds of vaccination for individuals who test positive for a target pathogen is compared with the odds of vaccination for individuals who test negative for that pathogen, adjusting for key confounders. The design is rapidly growing in popularity, but many open questions remain about its properties. In this paper, we examine temporal confounding by generalizing derivations to allow for time-varying vaccine status, including out-of-season controls, and open populations. We confirm that calendar time is an important confounder when vaccine status varies during the study. We demonstrate that, where time is not a confounder, including out-of-season controls can improve precision. We generalize these results to open populations. We use our theoretical findings to interpret 3 recent papers utilizing the test-negative design. Through careful examination of the theoretical properties of this study design, we provide key insights that can directly inform the implementation and analysis of future test-negative studies.