bluuebunny/crossref_metadata_2025 huggingface dataset:
Physics Games
Authors: Edge R. D.
Published: November 2020

There has been a move afoot among child psychologists for quite awhile to change some of our attitudes toward games. In the past, games have been primarily competitive, the object being to beat the opponents. Any cooperative spirit arose through one team combining against the other. Not all children are so combatively inclined, however. As a result, games have been devised which allow for a spirit of cooperation without the concomitant agression. One such is the lap game, (p. 172 of the New Games Book). In this, the group forms a circle, and each individual sits on the lap of the individual behind. The world record used to be 1,500 lapsitters. Of course, if one person falls over, a cooperative effect--essentially a soliton wave of non-lap-sitters--moves around the circle. The speed with which this occurs, though not equal to the speed of sound, is nevertheless very rapid. The thought occurs that many such games could be devised to demonstrate physical principles. This was brought home by Ruth Howes and James Watson, of Ball State University, demonstrating physical principles using the students themselves. The point was made that, in a large class, interaction on a personal basis, not merely between the professor and the student, but also between the students themselves, is virtually non-existent. Furthermore, such large classes are given, more often than not, in vast auditoria not designed for physics use, where there are no apparatus storage facilities, and it is difficult for the students at the back to see. At Ball State, they invite the students down, and a few of them mill around, bumping into one another, pretending they are “gas atoms”. This contact sport is evidently much appreciated by the students, provided it is not carried too far. Then more students come down, making closer contact, hands on shoulders, but breaking away to put hands on the shoulders of different students to form a liquid. Then, they put hands on the shoulders of the nearest individual and stick--a solid. Ruth Howes mentioned several other such simulations, which serve to
Miscellaneous
Authors: Edge R. D.
Published: November 2020

Experiment 15.01 Reaction - The Rocket and Balloon

Materials: - aluminum foil - match, paper clip
The Role of Toys in Teaching Physics
Authors: McCullough Jodi , McCullough Roy
Published: November 2020

This manual contains experiments, demonstrations, and displays involving toys that can be used to introduce most of the major topics covered in a typical introductory physics class. These activities provide a sense that everyday objects are closely related to the topics studied in physics. Using toys in teaching physics will certainly add excitement and enthusiasm to your classroom.
Laboratory Activities
Authors: McCullough Jodi , McCullough Roy
Published: November 2020

PageTopicToy3.2Mechanics: Kinematics in one dimensionConstant Motion Car3.4Mechanics: Kinematics in one dimensionStringracer3.6 Mechanics: Kinematics in two dimensionsDart Gun3.9Mechanics: Kinematics in two dimensionsToy Airplane3.11Mechanics: Vectors in two dimensionsGroove Tube3.14Mechanics: EnergyHot Wheels Car3.16Mechanics: EnergyBird on a Spring3.18Mechanics: MomentumRollerblades3.21Waves and SoundFive-Tone Twirler3.23LightOcean Desk Toy3.26LightMultiviewer3.28MagnetismFloating Magnets3.30Electromagnetism: Current ElectricityJungle Racer or Battery-Powered Car
Physics Contest Events
Authors: McCullough Jodi , McCullough Roy
Published: November 2020

The object of this activity is to hit a target with a dart shot out of a dart gun. The students are given a dart gun and dart, meter stick, and a stop watch. They are to bring with them calculators and pens or pencils. They have 15 minutes to make any measurements they wish. Then the dart guns are removed and they are assigned an angle they are to shoot the dart from and a height off the floor to place the gun. They have 10 minutes to calculate where the dart will land. The judge watches them shoot at a target. There are zones marked off on the target with point values ranging from 50 points down to 10 points. Their score is based on where they strike the target.
Modern Physics Ideas
Authors: McCullough Jodi , McCullough Roy
Published: November 2020

Developed by Robert Reiland, and available from Science Kit.
Test Questions
Authors: McCullough Jodi , McCullough Roy
Published: November 2020

1.1 — A bullet is shot straight into the air from ground level at a speed of 200.0 m/s. What is the speed of the bullet when it falls to the ground (neglect air resistance)?100.0 m/s0 m/s9.8 m/s200.0 m/s

ANS.

(D)
Teaching About Energy
Authors: Roeder John L.
Published: November 2020

This publication deals with how the human eye perceives color and how that color perception is triggered by the light sources and objects of our world. The colors of soap bubbles and other thin films are treated in more than usual detail, and the approach is extended to explain the colors of transparent materials sandwiched between polarizers.

A tonic for lagging interest in the spring semester, the resource book incor-porates many laboratory activities and demonstrations, including some new ones, important commercial applications, sample questions, and Physics Olympics events.
With You When You Fly: Aeronautics for Introductory Physics
Authors:   NASA,   AAPT
Published: November 2020

Although there are many right ways to teach physics, there is a growing need for teaching by inquiry in context. This is the most effective method, ensuring classes are relevant and practical. With You When You Fly is an educator’s guide that addresses this need, providing a solid content base and actively engaging with topics necessary to the development of 21st century skills.

With You When You Fly: Aeronautics for Introductory Physics is founded on 26 aeronautics-related teaching ideas presented by seasoned high school and college physics teachers, and articles that have appeared in the American Association of Physics Teachers’s (AAPT) publication, The Physics Teacher. The lesson ideas are combined with NASA aeronautics education resources and ongoing research, as well as student experiences with flight.

Reviewed by acting high school and college/university AAPT membersEach activity includes objectives and/or guiding questions related to the physics of flight, followed by a detailed listing of the NGSS and CCSS addressed by students who successfully complete each activityThe activities can also be used to teach fundamental physics concepts and inquiry skills.

With You When You Fly: Aeronautics for Introductory Physics is suitable for high school and introductory university level physics courses. Teachers as well as anyone interested in aeronautics and astrophysics will find this book useful and informative.
Overview
Authors:   NASA and AAPT
Published: November 2020

There are many right ways to teach physics. Teaching by inquiry in context is perhaps the most effective way to effectively teach physics so that it becomes both relevant and practical. This educators’ guide addresses a growing need for higher-level inquiry in the physics classroom, provides a solid content base, and actively engages with topics necessary to the development of 21st century skills. Context is provided from student experiences with flight as well as ongoing aeronautics research.
Scientific Thinking
Authors:   NASA and AAPT
Published: November 2020

ACTIVITY Scaling and Paper Airplanes
2-D Combination
Authors:   NASA and AAPT
Published: November 2020

ACTIVITY Measuring Flight Speeds from Photos
Energy
Authors:   NASA and AAPT
Published: November 2020

Estimate flight speed from a firebomber.
Year 2018 F=ma Contest
Authors: Kisačanin Branislav , Zhang Eric K.
Published: November 2020

In 2018, two F = ma exams were offered, Exam A and Exam B. This chapter contains problems and solutions for both exams.
Establishment of a stem Leydig cell line capable of 11-ketotestosterone production
Authors: Huang Qin , Yang Zhuo , Wang Jie , Luo Yubing , Zhao Changle , Li Minghui , Xiao Hesheng , Tao Wenjing , Wang Deshou , Wei Jing
Published: November 2020

The deficiency or insufficiency of androgen can trigger a range of reproductive diseases as well as other symptoms. Stem Leydig cells (SLCs) are critical for the formation and maintenance of a functional androgen-producing cell (Leydig cell, LC) population throughout adult male life. However, to date, our knowledge about SLCs is poor. Here we report the derivation and characterisation of a clonal stem LC line (designated as TSL) capable of 11- ketotestosterone (11-KT) production from a 3-month-old Nile tilapia (Oreochromis niloticus) testis. The cells retained stable proliferation after 77 generations with normal karyotype and growth factor dependency. They expressed platelet-derived growth factor receptor-α (pdgfrα), nestin and chicken ovalbumin upstream promoter transcription factor II (coup-tfIIa), which are characteristic of SLCs. Upon induction in defined medium, TSLs could undergo differentiation into steroidogenically active LCs and produce 11-KT. When implanted into recipient Nile tilapia testes from which endogenous LCs had been eliminated by ethane dimethanesulphonate (EDS) treatment, the PKH26-labelled TSLs could colonise the interstitium, subsequently express steroidogenic genes and restore 11-KT production. Taken together, our data suggest that TSLs possess the ability of continuous proliferation and potential of differentiation into functional LCs invitro and invivo. To the best of our knowledge TSL might represent the first stem LC line capable of 11-KT production to date. Our study may offer new opportunities for investigating the self-renewal of SLCs and steroidogenesis invitro, and provide an invaluable invitro model for investigating endocrine disruptors.
Correlated cryogenic fluorescence microscopy and electron cryo-tomography shows that exogenous TRIM5α can form hexagonal lattices or autophagy aggregates in vivo
Authors: Carter Stephen D. , Mamede João I. , Hope Thomas J. , Jensen Grant J.
Published: November 2020

Significance

One of the most notable features of TRIM5 proteins is their ability to restrict retroviral infections by binding viral capsids. TRIM5α forms highly dynamic puncta of various sizes, and, when purified, hexagonal nets on the surface of HIV virions, but the molecular ultrastructure of the cellular bodies and the relationship of the in vitro nets to HIV restriction has remained unclear. To define the cellular ultrastructure underlying the punctate and dynamic nature of YFP-rhTRIM5α bodies, we applied cryogenic correlated light and electron microscopy combined with electron cryo-tomography to TRIM5α bodies and observed YFP-rhTRIM5α-localization to organelles found along the aggrephagy branch of the autophagy pathway. Consistent with previous work, we also found that TRIM5α forms hexagonal nets inside cells.
The ER cholesterol sensor SCAP promotes CARTS biogenesis at ER–Golgi membrane contact sites
Authors: Wakana Yuichi , Hayashi Kaito , Nemoto Takumi , Watanabe Chiaki , Taoka Masato , Angulo-Capel Jessica , Garcia-Parajo Maria F. , Kumata Hidetoshi , Umemura Tomonari , Inoue Hiroki , Arasaki Kohei , Campelo Felix , Tagaya Mitsuo
Published: November 2020

In response to cholesterol deprivation, SCAP escorts SREBP transcription factors from the endoplasmic reticulum to the Golgi complex for their proteolytic activation, leading to gene expression for cholesterol synthesis and uptake. Here, we show that in cholesterol-fed cells, ER-localized SCAP interacts through Sac1 phosphatidylinositol 4-phosphate (PI4P) phosphatase with a VAP–OSBP complex, which mediates counter-transport of ER cholesterol and Golgi PI4P at ER–Golgi membrane contact sites (MCSs). SCAP knockdown inhibited the turnover of PI4P, perhaps due to a cholesterol transport defect, and altered the subcellular distribution of the VAP–OSBP complex. As in the case of perturbation of lipid transfer complexes at ER–Golgi MCSs, SCAP knockdown inhibited the biogenesis of the trans-Golgi network–derived transport carriers CARTS, which was reversed by expression of wild-type SCAP or a Golgi transport–defective mutant, but not of cholesterol sensing–defective mutants. Altogether, our findings reveal a new role for SCAP under cholesterol-fed conditions in the facilitation of CARTS biogenesis via ER–Golgi MCSs, depending on the ER cholesterol.
Optimized gene engineering of murine CAR-T cells reveals the beneficial effects of IL-15 coexpression
Authors: Lanitis Evripidis , Rota Giorgia , Kosti Paris , Ronet Catherine , Spill Aodrenn , Seijo Bili , Romero Pedro , Dangaj Denarda , Coukos George , Irving Melita
Published: November 2020

Limited clinical benefit has been demonstrated for chimeric antigen receptor (CAR) therapy of solid tumors, but coengineering strategies to generate so-called fourth-generation (4G) CAR-T cells are advancing toward overcoming barriers in the tumor microenvironment (TME) for improved responses. In large part due to technical challenges, there are relatively few preclinical CAR therapy studies in immunocompetent, syngeneic tumor-bearing mice. Here, we describe optimized methods for the efficient retroviral transduction and expansion of murine T lymphocytes of a predominantly central memory T cell (TCM cell) phenotype. We present a bicistronic retroviral vector encoding both a tumor vasculature–targeted CAR and murine interleukin-15 (mIL-15), conferring enhanced effector functions, engraftment, tumor control, and TME reprogramming, including NK cell activation and reduced presence of M2 macrophages. The 4G-CAR-T cells coexpressing mIL-15 were further characterized by up-regulation of the antiapoptotic marker Bcl-2 and lower cell-surface expression of the inhibitory receptor PD-1. Overall, this work introduces robust tools for the development and evaluation of 4G-CAR-T cells in immunocompetent mice, an important step toward the acceleration of effective therapies reaching the clinic.
Quasinormal modes of Kerr–de Sitter black holes via the Heun function
Authors: Hatsuda Yasuyuki
Published: November 2020

This note addresses quasinormal mode (QNM) frequencies of four-dimensional asymptotically de Sitter rotating black holes. The main motivation is that Mathematica 12.1 has implemented a new family of special functions: Heun functions. Using the fact that Teukolsky’s equations for Kerr–de Sitter black holes are mapped to Heun’s equations, we are able to compute their QNM frequencies by the Heun function. In this approach, Mathematica normally evaluates these frequencies to arbitrary numerical precision in a few seconds. We further discuss an application to asymptotically flat rotating black holes.
Modern demonstration experiments for H Hertz’s experimental study
Authors: Mayer V V , Varaksina E I
Published: November 2020

A modern version of Hertz’s classical experiments that demonstrate the electromagnetic nature of light waves is proposed herein. The demonstration kit includes a 433 MHz micropower generator, a sufficiently sensitive electromagnetic-radiation detector with an LED output, two semi-wave vibrators, a rod polariser, an LED flashlight, three Polaroid polarisers, and a matte screen.
Speeded-Up Robust Features-based image mosaic method for large-scale microscopic hyperspectral pathological imaging
Authors: Zhang Qing , Sun Li , Chen Jiangang , Zhou Mei , Hu Menghan , Wen Ying , Li Qingli
Published: November 2020

Microscopic hyperspectral imaging technology has been widely used in pathological analysis as it can obtain both spatial and spectral information of samples. However, most hyperspectral imaging systems can only capture images in a single field of view. Therefore, an image mosaic is one of the most important steps in a large-scale microscopic hyperspectral imaging system. This paper proposes a microscopic hyperspectral image (HSI) mosaic method based on Speeded-Up Robust Features (SURF) and linear synthesis to achieve large-scale HSIs. In contrast to other SURF-based image mosaic methods, the proposed method leverages both image content and coordinate information to improve the accuracy and stability of the image mosaic. In addition, multiple bands of HSIs with different texture information and grayscale are applied in image matching to take full advantage of spatial redundancy. Simultaneously, a blank microscopic HSI screening method is introduced in this paper to pick out a clearer blank image for better preprocessing, i.e. removing interference in the optical path and the interference of dust on slides. Finally, the preprocessed images are synthesized by linear-based synthesis methods due to their simple synthesis structure and better universality. Additionally, a file format, i.e. hyperslide, is defined for large-scale HSIs and can be browsed with HyperViewer software. Experimental results show that the proposed microscopic HSI mosaic method can obtain high-quality large-scale microscopic HSIs of tissue sections.
Pomegranate-like silicon-based anodes self-assembled by hollow-structured Si/void@C nanoparticles for Li-ion batteries with high performances
Authors: Chen Dajin , Tao Chuanying , Chen Tongzhou , Liu Xiaohan , Liu Yong , Xu Gang , Han Gaorong
Published: November 2020

Silicon is considered as one of the most promising alternatives to the graphite anode for lithium-ion batteries due to its high theoretical capacity (4200 mAh g−1). However, its fragile solid electrolyte interphase cannot tolerate the large volume changes of bare silicon induced by the lithium insertion and extraction, resulting in low Coulombic efficiency. In previous reports, a yolk-shell design, such as Si@void@C, in which the well-defined space allows the silicon particles to expand freely without breaking the outer carbon shells, can effectively improve the Columbic efficiency. Here, we design a pomegranate-like silicon-based anodes self-assembled by the hollow-structured Si/void@C nanoparticles, in which silicon and some voids are together sealed in the outer carbon shells, by the magnesiothermic reduction of the colloidal SiO2@PEI nanospheres prepared by the hydrolysis of the tetraethoxysilane under the catalytic effect of polyetherimide (PEI). Due to the tolerance of the presealed void in the carbon shells of the primary hollow-structured Si/void@C nanoparticles, the prepared pomegranate-like silicon-based anodes deliver a high reversible capacity of 1615 mAh g−1 at 0.1 C and long cycle life of 73.5% capacity retention at 2 C after 500 cycles, as well as high Coulombic efficiency of 99%.
Positive and negative photoconductivity characteristics in CsPbBr3/graphene heterojunction
Authors: Jin Haonan , Chen Yibo , Zhang Louwen , Wan Rui , Zou Zhengguang , Li Haixia , Gao Yihua
Published: November 2020

Broadband response photodetectors have received great research interest in optical sensing field. Usually, materials with positive photoconductivity (PPC) are general and the lack of negative photoconductivity (NPC) materials limits the application of photoelectric effect, especially in the broadband photodetecting field. Therefore, the finding of NPC materials is very important. Integrating PPC and NPC response into a single device is extremely meaningful to the development of broadband photodetector. In this work, we fabricated CsPbBr3 nanocrystals (NCs)-multilayered graphene heterojunction, which achieved persistent NPC response to ultra violet (300–390 nm) and PPC response to visible light (420–510 nm). The persistent NPC relies on the desorption of H2O vapor, and varies its intensity with the power intensity of laser. The PPC relies on the holes transmission from NCs to graphene. The recombination of NPC and PPC effect provides background knowledge for the development of broadband photodetector.
The use of near-axis magnetic fields for stellarator turbulence simulations
Authors: Jorge R , Landreman M
Published: November 2020

The design of turbulence optimized stellarators has so far relied on three-dimensional equilibrium codes such as VMEC in order to find the minimum of a given objective function. In this work, we propose a complimentary approach based on the near-axis expansion to compute the geometry parameters of neoclassicaly optimized stellarators used in turbulence studies. As shown here, the near-axis expansion can be a reasonable approximation of the geometric parameters relevant for turbulence and stability simulations of the core of existing optimized stellarator designs. In particular, we examine the geometry coefficients that appear in the gyrokinetic equation, the drift-reduced fluid equations and the ideal ballooning equation. This approach may allow for the development of new stellarator optimization techniques significantly faster than conventional methods.
CMOS analog and mixed-signal phase-locked loops: An overview
Authors: Zhang Zhao
Published: November 2020

CMOS analog and mixed-signal phase-locked loops (PLL) are widely used in varies of the system-on-chips (SoC) as the clock generator or frequency synthesizer. This paper presents an overview of the AMS-PLL, including: 1) a brief introduction of the basics of the charge-pump based PLL, which is the most widely used AMS-PLL architecture due to its simplicity and robustness; 2) a summary of the design issues of the basic CPPLL architecture; 3) a systematic introduction of the techniques for the performance enhancement of the CPPLL; 4) a brief overview of ultra-low-jitter AMS-PLL architectures which can achieve lower jitter (< 100 fs) with lower power consumption compared with the CPPLL, including the injection-locked PLL (ILPLL), sub-sampling (SSPLL) and sampling PLL (SPLL); 5) a discussion about the consideration of the AMS-PLL architecture selection, which could help designers meet their performance requirements.
Challenges and opportunities toward fully automated analog layout design
Authors: Chen Hao , Liu Mingjie , Tang Xiyuan , Zhu Keren , Sun Nan , Pan David Z.
Published: November 2020

Realizing the layouts of analog/mixed-signal (AMS) integrated circuits (ICs) is a complicated task due to the high design flexibility and sensitive circuit performance. Compared with the advancements of digital IC layout automation, analog IC layout design is still heavily manual, which leads to a more time-consuming and error-prone process. In recent years, significant progress has been made in automated analog layout design with emerging of several open-source frameworks. This paper firstly reviews the existing state-of-the art AMS layout synthesis frameworks with focus on the different approaches and their individual challenges. We then present recent research trends and opportunities in the field. Finally, we summaries the paper with open questions and future directions for fully-automating the analog IC layout.
Probing Beyond Standard Model Physics via Oscillations with IceCube DeepCore
Authors: Blot S.
Published: November 2020

For many years IceCube DeepCore has measured atmospheric neutrino interactions in the optically clear, deep ice at the South Pole. Analysing only three years of data has yielded the most precise measurements of the atmospheric neutrino oscillation parameters above 5 GeV. Measuring oscillations at these high energies, well above the tau-production threshold, and over extremely long baselines, provides strong constraints on new, Beyond Standard Model physics in a region of phase space uniquely accessed with atmospheric neutrinos. Here we report on the most recent searches for non-standard atmospheric neutrino oscillations with IceCube DeepCore.
Higher-order kinematic analyses of a planar parallel robot based on screw theory
Authors: Rodelo M , Villa J L , Yime E
Published: November 2020

This paper presents the higher-order kinematic analyses of a planar parallel robot, addressed by means of the theory of screws. The reduced velocity, acceleration, jerk and hyper-jerk state for the end-effector of robot was developed as a spatial vector by applying the concept of Lie algebra and helicoidal vector field. In order to verify the effectiveness of this theoretical development, the kinematics models obtained was solved and simulated in MATLAB environment, using Freeth’s Nephroid trajectory as reference path for tracking with the end-effector. The simulation results proved that this type of spatial notation is convenient, because it allows us to quickly develop equations of motion and express them succinctly in symbolic form, reducing the volume of algebra, simplifying the modeling tasks, implementation and execution the algorithms used to solve kinematic problems in parallel robots. The major contribution of this work is the possibility of extended the classical kinematic analysis to a high order system; where the application of screw theory becomes a safe and reliable mathematical tool, which may be successfully used on parallel planar robots with singular configurations, represented with helicoidal vector field.
Brief numerical analysis of (3+1) Ginzburg-Landau equations
Authors: Aguirre C , Martins Q , Barba-Ortega J
Published: November 2020

In this contribution, we show the implementation of the Link-variable method for solve the complete set of acopled non-linear time dependent Ginzburg-Landau differential equations in a three-dimensional homogeneous and isotropic mesoscopic superconducting system. In this case, the sample is immersed in an external magnetic d at zero applied current. The effects of demagnetization are taken in count and we show the order parameter and its phase in zero field cooling and field cooling process. This numerical analysis shows good results when this solution is applied to a superconducting cubic sample.
Evaluation of the mechanical behaviour to the force of tension between thermoplastic materials of origin and recycled
Authors: Palacios-Alvarado W , Medina-Delgado B , Durán-Urón A E
Published: November 2020

The use of plastic products and polymeric matrix compounds is increasing in engineering, most of these materials are subjected to dynamic loads, therefore, are constantly evaluated according to experimental methods that allow a characterization of their main properties. Therefore, this research work consisted in carrying out the characterization of mechanical properties of thermoplastic materials of different origin; commercial and recycled, where three cases were worked: Polymethylmethacrylate, polyvinyl chloride and polypropylene, for which there were 3.5 ± 0.1 mm thick sheets, manufactured by extrusion and supplied by a local supplier, in the city of San José de Cúcuta, Colombia. Afterwards, the specimens or samples were cut for the tension test adapting the shape and geometry, according to the standard test method for tensile properties of plastics, ASTM D638-14, using laser cutting for such purpose, the specimens were conditioned at a temperature of 20 °C during 40 hours prior to the moment of the tension test, the equipment used was a universal machine branded from Electro Mechanical Instrument & Components Corp., commercial reference DL2000 N° 11760 NS 784 with a speed adjustment of 5 mm/min to keep within the times given by the standard. Once the tests are performed, the stress/strain graphs of each case studied are obtained and the experimental results are analyzed from the data provided by the software “Tesc versão 4.00”. Afterwards, Young’s module is statistically analyzed and compared in each study, seeing which one presents the best behavior under the studied load conditions, raising a hypothesis, where the question is if the differences in the sample between Young’s module can come from a population with an mean of zero, in this case, it is concluded that there is no difference between Young’s modulus values for polymethylmethacrylate samples, the same occurred for polyvinyl chloride and polypropylene.
Aerodynamic efficiency of gliding birds vs comparable UAVs: a review
Authors: Harvey Christina , Inman Daniel J
Published: November 2020

Here, we reviewed published aerodynamic efficiencies of gliding birds and similar sized unmanned aerial vehicles (UAVs) motivated by a fundamental question: are gliding birds more efficient than comparable UAVs? Despite a multitude of studies that have quantified the aerodynamic efficiency of gliding birds, there is no comprehensive summary of these results. This lack of consolidated information inhibits a true comparison between birds and UAVs. Such a comparison is complicated by variable uncertainty levels between the different techniques used to predict avian efficiency. To support our comparative approach, we began by surveying theoretical and experimental estimates of avian aerodynamic efficiency and investigating the uncertainty associated with each estimation method. We found that the methodology used by a study affects the estimated efficiency and can lead to incongruent conclusions on gliding bird aerodynamic efficiency. Our survey showed that studies on live birds gliding in wind tunnels provide a reliable minimum estimate of a birds’ aerodynamic efficiency while simultaneously quantifying the wing configurations used in flight. Next, we surveyed the aeronautical literature to collect the published aerodynamic efficiencies of similar-sized, non-copter UAVs. The compiled information allowed a direct comparison of UAVs and gliding birds. Contrary to our expectation, we found that there is no definitive evidence that any gliding bird species is either more or less efficient than a comparable UAV. This non-result highlights a critical need for new technology and analytical advances that can reduce the uncertainty associated with estimating a gliding bird’s aerodynamic efficiency. Nevertheless, our survey indicated that species flying within subcritical Reynolds number regimes may inspire UAV designs that can extend their operational range to efficiently operate in subcritical regimes. The survey results provided here point the way forward for research into avian gliding flight and enable informed UAV designs.
Evolutionary Diversification in Insect Vector–Phytoplasma–Plant Associations
Authors: Trivellone V , Dietrich C H
Published: November 2020

The association between insect herbivores and vascular plants represents one of the greatest success stories in terrestrial evolution. Specific mechanisms generating diversity in the association remain poorly understood, but it has become increasingly clear that microbes play important roles in mediating plant–insect interactions. Previous research on phytoplasmas (Acholeplasmatales: Acholeplasmataceae), a diverse group of plant-pathogenic bacteria, and their hemipteran insect vectors suggests that this system provides a new model for understanding how interactions among distantly related but ecologically associated groups of organisms can drive evolutionary diversification. Phytoplasma infections affect the phenotypes of both plants and vectors, altering functional traits (e.g., diet breadth) and mediating host shifts which may, in turn, alter genetic and phylogenetic patterns. This review highlights previous research on the functional ecology and phylogenetic components of phytoplasma-plant-vector (PPV) associations relevant to the evolutionary diversification of this system. Although phytoplasmas and their hosts occur in most terrestrial biomes and have evolved together over the past 300+ million years, major gaps in knowledge of PPV associations remain because most prior research on the system focused on strategies for mitigating effects of phytoplasma diseases in agroecosystems. Study of this system within a broader evolutionary context could help elucidate mechanisms by which interactions between insect herbivores, microbes, and plants drive biological diversification and also help predict the emergence of diseases affecting agriculture. Future research should more thoroughly document PPV associations in natural habitats, examine the relative prevalence of cospeciation versus host shifts in this system, and test possible macroevolutionary consequences of host manipulation by phytoplasmas.
An overview of cancer health disparities: new approaches and insights and why they matter
Authors: Minas Tsion Zewdu , Kiely Maeve , Ajao Anuoluwapo , Ambs Stefan
Published: November 2020

Cancer health disparities remain stubbornly entrenched in the US health care system. The Affordable Care Act was legislation to target these disparities in health outcomes. Expanded access to health care, reduction in tobacco use, uptake of other preventive measures and cancer screening, and improved cancer therapies greatly reduced cancer mortality among women and men and underserved communities in this country. Yet, disparities in cancer outcomes remain. Underserved populations continue to experience an excessive cancer burden. This burden is largely explained by health care disparities, lifestyle factors, cultural barriers, and disparate exposures to carcinogens and pathogens, as exemplified by the COVID-19 epidemic. However, research also shows that comorbidities, social stress, ancestral and immunobiological factors, and the microbiome, may contribute to health disparities in cancer risk and survival. Recent studies revealed that comorbid conditions can induce an adverse tumor biology, leading to a more aggressive disease and decreased patient survival. In this review, we will discuss unanswered questions and new opportunities in cancer health disparity research related to comorbid chronic diseases, stress signaling, the immune response, and the microbiome, and what contribution these factors may have as causes of cancer health disparities.
Bi-atrial thrombosis in a patient with SARS-CoV-2 infection: a case report
Authors: Torres Ricardo , Gul Fahad , Azmaiparashvili Zurab , Patarroyo-Aponte Gabriel
Published: November 2020

Background

Coronavirus disease 2019 (COVID-19) is a rapidly spreading pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It is a multisystemic disease associated with micro- and macrovascular thrombo-embolic complications, including intracardiac thrombosis, which has not been previously reported in the literature.

Case summary

We report a case of a 68-year-old woman with COVID-19 admitted to our intensive care unit with acute respiratory distress, undifferentiated shock, hyperkalaemia, acute kidney injury, and coagulopathy. She received crystalloid infusion, broad-spectrum antibiotics, hydroxychloroquine, insulin–dextrose, calcium gluconate, sodium bicarbonate, and i.v. vasopressors. Continuous renal replacement therapy (CRRT) was started for refractory hyperkalaemia and metabolic acidosis. Transthoracic echocardiogram obtained for concern of pulmonary embolism found bi-atrial thrombosis with normal bi-ventricular dimensions and function. Systemic anticoagulation was provided, but this was stopped soon afterwards due to worsening coagulopathy and bleeding. Despite intensive measures and supportive therapy, the patient developed worsening hypoxia, refractory shock, and multiorgan failure. After discussion of goals of care with her family, a decision was made to initiate hospice care. The patient died within 72 h of hospital admission.

Discussion

Infection with SARS-CoV-2 is a multisystemic disease that primarily affects the lungs, but also predisposes to rare thrombo-embolic phenomena such as intracardiac thrombosis.
Case report: hepatobronchial lymphatic communications in single ventricle patients as a pathophysiological mechanism of plastic bronchitis: diagnosis and treatment
Authors: Rabinowitz Deborah , Radtke Wolfgang , Bhat Majeed , Itkin Maxim
Published: November 2020

Background 

Plastic bronchitis is a rare but devastating complication in single ventricle patients after Fontan completion. Recent advances in dynamic contrast-enhanced magnetic resonance lymphangiogram demonstrate the typical pathophysiological mechanism of the thoracic duct leaking lymphatic fluid towards the bronchi resulting in intraluminal casts. This has been termed abnormal pulmonary lymphatic perfusion and has been successfully treated in 94% of patients with thoracic duct occlusion. However, in some cases, this aberrant flow is not identified and therefore no intervention is available. This case report identifies a newly discovered origin of abnormal lymphatic flow from the liver to the bronchi and the treatment of these patients.

Case summary 

We report two cases of plastic bronchitis in single ventricle patients with no identified abnormal lymphatic pulmonary perfusion from the thoracic duct. Both patients underwent liver lymphangiogram and demonstrated aberrant flow from the hepatic lymphatic ducts to the bronchi. These were successfully occluded, and plastic bronchitis symptoms resolved in both cases.

Discussion 

The recent discovery of the abnormal pulmonary lymphatic perfusion from the thoracic duct to the bronchi has allowed successful treatment of 94% of single ventricle patients with plastic bronchitis. The discovery of hepatobronchial lymphatic perfusion reveals an occult aetiology of plastic bronchitis and a second target for embolization and successful treatment.
Retracts of Free Groups and a Question of Bergman
Authors: Snopce Ilir , Tanushevski Slobodan , Zalesskii Pavel
Published: November 2020

Let $F_n$ be a free group of finite rank $n \geq 2$. We prove that if $H$ is a subgroup of $F_n$ with $\textrm {rk}(H)=2$ and $R$ is a retract of $F_n$, then $H \cap R$ is a retract of $H$. However, for every $m \geq 3$ and every $1 \leq k \leq n-1$, there exist a subgroup $H$ of $F_n$ of rank $m$ and a retract $R$ of $F_n$ of rank $k$ such that $H \cap R$ is not a retract of $H$. This gives a complete answer to a question of Bergman. Furthermore, we prove that $\textrm {rk}(H \cap \textrm {Fix}(S)) \leq \textrm {rk}(H)$ for every family $S$ of endomorphisms of $F_n$ and every subgroup $H$ of $F_n$ with $\textrm {rk}(H) \leq 3$.
Immunogenicity of Reduced-Dose Monovalent Type 2 Oral Poliovirus Vaccine in Mocuba, Mozambique
Authors: de Deus Nilsa , Capitine Igor Paulo Ubisse , Bauhofer Adilson Fernando Loforte , Marques Selma , Cassocera Marta , Chissaque Assucênio , Bero Diocreciano Matias , Langa José Paulo , Padama Fernando Manuel , Jeyaseelan Visalakshi , Oberste M Steven , Estivariz Concepcion F , Verma Harish , Jani Ilesh , Mach Ondrej , Sutter Roland W
Published: November 2020

Background

The monovalent type 2 oral poliovirus vaccine (mOPV2) stockpile is low. One potential strategy to stretch the existing mOPV2 supply is to administer a reduced dose: 1 drop instead of 2.

Methods

We conducted a randomized, controlled, open-label, noninferiority trial (10% margin) to compared immunogenicity after administration of 1 versus 2 drops of mOPV2. We enrolled 9–22-month-old infants from Mocuba district of Mozambique. Poliovirus neutralizing antibodies were measured in serum samples collected before and 1 month after mOPV2 administration. Immune response was defined as seroconversion from seronegative (<1:8) at baseline to seropositive (≥1:8) after vaccination or boosting titers by ≥4-fold for those with titers between 1:8 and 1:362 at baseline. The trial was registered at anzctr.org.au (no. ACTRN12619000184178p).

Results

We enrolled 378 children, and 262 (69%) completed per-protocol requirements. The immune response of mOPV2 was 53.6% (95% confidence interval, 44.9%–62.1%) and 60.6% (52.2%–68.4%) in 1-drop and 2-drop recipients, respectively. The noninferiority margin of the 10% was not reached (difference, 7.0%; 95% confidence interval, −5.0% to 19.0%).

Conclusion

A small loss of immunogenicity of reduced mOPV2 was observed. Although the noninferiority target was not achieved, the Strategic Advisory Group of Experts on Immunization recommended the 1-drop strategy as a dose-sparing measure if mOPV2 supplies deteriorate further.
What’s Sex Got to Do With It? Understanding Potential Confounding and Exposure Misclassification in Mechanistic Sexually Transmitted Infection Research
Authors: Deese Jennifer , Wang Meng , Lapple Dana , Nelson Julie A E , Kuerten Bethany , Steiner Markus J , Chen Pai Lien , Hobbs Marcia M
Published: November 2020

We conducted a prospective study of 13 heterosexual couples to understand the impact of recent condomless vaginal sex on vaginal immune marker measurement and potential exposure misclassification due to the presence of semen. All immune markers were detectable in semen and concentrations of vaginal immune markers varied by sex recency.
Phase imaging dislocations using diffracted beam interferometry
Authors: Herring Rodney
Published: November 2020

A phase imaging method that measures the phase shift existing at a dislocation’s core is described. The method uses the interference of two symmetrically diffracted beams on the optic axis by means of an electron biprism. Each diffracted beam carries half the phase of the dislocation core. When combined, the entire phase shift of the dislocation core is obtained.
Heterotopic gastric mucosa in the gallbladder—a rare find
Authors: Cunha Roberto , Parreira Rafaela , Quintanilha Rui , Carneiro Vítor , Medeiros Armando , Leite Inês
Published: November 2020

It is universally known and accepted that the development of a certain type of tissue outside its usual location, like in the gastrointestinal tract, can occur. This is a relatively common situation in the upper region of the gastrointestinal tract. However, the development of gastric mucosa in the gallbladder is a rare find. The following is the case of a 22-year-old male with an 18 mm gallbladder polyp, who electively underwent a laparoscopic cholecystectomy, having been diagnosed at a histopathological level with heterotopic gastric mucosa in the gallbladder. This brief article also aims to provide a reflection on the possible evolution of neoplasms from this histological change, based on the doubts raised in literature.
NNIL-formulas revisited: Universal models and finite model property
Authors: Ilin Julia , de Jongh Dick , Yang Fan
Published: November 2020

NNIL-formulas, introduced by Visser in 1983–1984 in a study of $\varSigma _1$-subsitutions in Heyting arithmetic, are intuitionistic propositional formulas that do not allow nesting of implication to the left. The first results about these formulas were obtained in a paper of 1995 by Visser et al. In particular, it was shown that NNIL-formulas are exactly the formulas preserved under taking submodels of Kripke models. Recently, Bezhanishvili and de Jongh observed that NNIL-formulas are also reflected by the colour-preserving monotonic maps of Kripke models. In the present paper, we first show how this observation leads to the conclusion that NNIL-formulas are preserved by arbitrary substructures not necessarily satisfying the topo-subframe condition. Then, we apply it to construct universal models for NNIL. It follows from the properties of these universal models that NNIL-formulas are also exactly the formulas that are reflected by colour-preserving monotonic maps. By using the method developed in constructing the universal models, we give a new direct proof that the logics axiomatized by NNIL-axioms have the finite model property.
On the impact of baryons on the halo mass function, bias, and cluster cosmology
Authors: Castro Tiago , Borgani Stefano , Dolag Klaus , Marra Valerio , Quartin Miguel , Saro Alexandro , Sefusatti Emiliano
Published: November 2020

Luminous matter produces very energetic events, such as active galactic nuclei and supernova explosions, that significantly affect the internal regions of galaxy clusters. Although the current uncertainty in the effect of baryonic physics on cluster statistics is subdominant as compared to other systematics, the picture is likely to change soon as the amount of high-quality data is growing fast, urging the community to keep theoretical systematic uncertainties below the ever-growing statistical precision. In this paper, we study the effect of baryons on galaxy clusters, and their impact on the cosmological applications of clusters, using the magneticum suite of cosmological hydrodynamical simulations. We show that the impact of baryons on the halo mass function can be recast in terms on a variation of the mass of the haloes simulated with pure N-body, when baryonic effects are included. The halo mass function and halo bias are only indirectly affected. Finally, we demonstrate that neglecting baryonic effects on haloes mass function and bias would significantly alter the inference of cosmological parameters from high-sensitivity next-generations surveys of galaxy clusters.
Addressing γ-ray emissions from dark matter annihilations in 45 Milky Way satellite galaxies and in extragalactic sources with particle dark matter models
Authors: Halder Ashadul , Banerjee Shibaji , Pandey Madhurima , Majumdar Debasish
Published: November 2020

The mass-to-luminosity ratio of the dwarf satellite galaxies in the Milky Way suggests that these dwarf galaxies may contain substantial dark matter. The dark matter at the dense region such as within or at the vicinity of the centres of these dwarf galaxies may undergo the process of self-annihilation and produce γ-rays as the end product. The satellite borne γ-ray telescope such as Fermi-LAT reported the detection of γ-rays from around 45 Dwarf Spheroidals (dSphs) of Milky Way. In this work, we consider particle dark matter models described in the literature and after studying their phenomenologies, we calculate the γ-ray fluxes from the self-annihilation of the dark matter within the framework of these models in case of each of these 45 dSphs. We then compare the computed results with the observational upper bounds for γ-ray flux reported by Fermi-LAT and Dark Energy Survey for each of the 45 dSphs. The fluxes are calculated by adopting different dark matter density profiles. We then extend similar analysis for the observational upper bounds given by Fermi-LAT for the continuum γ-ray fluxes originating from extragalactic sources.
On the lifetime of bioinformatics web services
Authors: Kern Fabian , Fehlmann Tobias , Keller Andreas
Published: November 2020

Web services are used through all disciplines in life sciences and the online landscape is growing by hundreds of novel servers annually. However, availability varies, and maintenance practices are largely inconsistent. We screened the availability of 2396 web tools published during the past 10 years. All servers were accessed over 133 days and 318 668 index files were stored in a local database. The number of accessible tools almost linearly increases in time with highest availability for 2019 and 2020 (∼90%) and lowest for tools published in 2010 (∼50%). In a 133-day test frame, 31% of tools were always working, 48.4% occasionally and 20.6% never. Consecutive downtimes were typically below 5 days with a median of 1 day, and unevenly distributed over the weekdays. A rescue experiment on 47 tools that were published from 2019 onwards but never accessible showed that 51.1% of the tools could be restored in due time. We found a positive association between the number of citations and the probability of a web server being reachable. We then determined common challenges and formulated categorical recommendations for researchers planning to develop web-based resources. As implication of our study, we propose to develop a repository for automatic API testing and sustainability indexing.
Trustworthiness, Stability and Productivity of Minority Governments in Australia
Authors: Brenton Scott , Pickering Heath
Published: November 2020

In this study, we question commonly held negative perceptions of minority governments and determine whether they can be trusted to deliver on the promises contained in governance agreements, whether they are stable in being able to govern over full terms of parliament, and whether they are productive in being able to successfully pass legislation. We examine eight minority government agreements and the following eight majority government opening parliamentary agendas in Australian national and state governments from 1989 to 2018 and compare their performance using legislative data. The main differences are not how long they last or how much legislation they pass, but rather that majority governments generally make more commitments, particularly more policy-focused commitments. They are also more successful in fulfilling their promises, albeit not completely. We theorise that major parties faced with having to form a minority government agreement will overpromise in order to secure power but can underdeliver due to the risks for minor parties and independents in forcing elections over breaches.