bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermal transpiration in molecular gas
Authors: Wang Peng , Su Wei , Wu Lei
Published: August 2020

The thermal transpiration of molecular gas is investigated based on the model of Wu et al. [“A kinetic model of the Boltzmann equation for non-vibrating polyatomic gases,” J. Fluid Mech. 763, 24–50 (2015)], which is solved by a synthetic iterative scheme efficiently and accurately. A detailed investigation of the thermal slip coefficient, Knudsen layer function, and mass flow rate for molecular gas interacting with the inverse power-law potential is performed. It is found that (i) the thermal slip coefficient and Knudsen layer function increase with the viscosity index determined by the intermolecular potential. Therefore, at small Knudsen number, gas with a larger viscosity index has a larger mass flow rate; however, at late transition and free molecular flow regimes, this is reversed. (ii) The thermal slip coefficient is a linear function of the accommodation coefficient in Maxwell’s diffuse–specular boundary condition, while its variation with the tangential momentum accommodation coefficient is complicated in Cercignani–Lampis’s boundary condition. (iii) The ratio of the thermal slip coefficients between monatomic and molecular gases is roughly the ratio of their translational Eucken factors, and thus, molecular gas always has a lower normalized mass flow rate than monatomic gas. (iv) In the transition flow regime, the translational Eucken factor continues to affect the mass flow rate of thermal transpiration, but in the free molecular flow regime, the mass flow rate converges to that of monatomic gas. Based on these results, accommodation coefficients were extracted from thermal transpiration experiments of air and carbon dioxide, which are found to be 0.9 and 0.85, respectively, rather than unity used in the literature. The methodology and data presented in this paper are useful, e.g., in the pressure correction of capacitance diaphragm gauge when measuring low gas pressures.
Spinning behavior of flow-acoustic resonant fields inside a cavity: Vortex-shedding modes and diametral acoustic modes
Authors: Wang Peng , Liu Yingzheng
Published: August 2020

The spinning behavior of flow-acoustic resonant fields inside an axisymmetric cavity configuration was numerically investigated in four flow conditions containing different resonances between vortex-shedding modes and diametral acoustic modes. Zonal large-eddy simulations (ZLESs) were conducted to determine the aeroacoustic and aerodynamic fields simultaneously. In the ZLESs, a shear stress transport turbulence model was used to model the relatively steady flow field inside the inlet and outlet sections. Simultaneously, the wall-modeled LES formulation was used in the cavity section to resolve the highly complex flow-acoustic resonant fields. The ZLES results were well validated by the experimental results in the literature in terms of the frequency, amplitude, and spatial features of the acoustic pressure pulsations. Subsequently, the spinning behavior and mechanism of the excited diametral acoustic modes and the resonant vortex-shedding modes were comprehensively illustrated. The results showed that the excited diametral acoustic mode span anticlockwise along the cavity circumference, resulting in intense acoustic-pressure fluctuations several times greater than at the inlet dynamic-pressure head, together with longitudinal pressure propagations. Using proper orthogonal decomposition analysis, the spinning mechanism was found to be closely related to the interaction between the α-mode and the β-mode, which had fixed temporal and spatial phase lags. Thereafter, the first vortex-shedding mode gave rise to a strong spinning motion of the resonant flow field, while the second vortex-shedding mode created a slight spinning motion. The corresponding phase-dependent flow fields at consecutive planes along the cavity circumference revealed the spatiotemporal evolution of the velocity variations, surface streamlines, and vorticity variations of the shedding vortices. Large-scale helical vortex tubes were formed within the cavity volume due to the strong spinning behavior.
Strain-induced structural transition in DyBa2Cu3O7−x films grown by atomic layer-by-layer molecular beam epitaxy
Authors: Putzky D. , Radhakrishnan P. , Wang Y. , Wochner P. , Christiani G. , Minola M. , van Aken P. A. , Logvenov G. , Benckiser E. , Keimer B.
Published: August 2020

We have used atomic layer-by-layer molecular beam epitaxy to synthesize coherently lattice-matched thin films of the high-temperature superconductor DyBa2Cu3O7−x with minimal defect density. A systematic set of x-ray reciprocal-space maps reveals tetragonal and orthorhombic structures with different twinning patterns and elucidates their evolution with the thickness, the oxygenation state, and the epitaxial relationship with the substrate. We also show that films with more pronounced orthorhombicity exhibit lower normal-state resistivities and higher superconducting transition temperatures. These findings provide guidance for the synthesis of optimized superconducting heterostructures and devices.
Magnetic relaxation dependences on the central ions for Ln (Ln = Tb, Dy, Er) phthalocyanines
Authors: Ruan Liuxia , Tong Junwei , Li Linrui , Luo Feifei , Zhang Rui , Qin Gaowu , Zhang Xianmin
Published: August 2020

Magnetic behavior dependences on the central ions for Ln (Ln = Tb, Dy, Er) phthalocyanines have been studied using direct current and alternating current magnetic susceptibility measurements. The direct current magnetic susceptibility results indicate that the product of the molar magnetic susceptibility and temperature is close to the theoretical value for the current Ln phthalocyanines. A further analysis using the Curie–Weiss law demonstrates the existence of an antiferromagnetic interaction between the Ln ions. Alternating current magnetic susceptibility measurement indicates that both Tb and Dy ions exhibit a slow relaxation with the phthalocyanine ligands compared to that of the Er ion. The effective energy barriers estimated in quantity using the Arrhenius law are 740 K and 40 K for Tb and Dy phthalocyanines, respectively. A theoretical fitting for Cole–Cole plots by the generalized Debye model demonstrates that the Orbach relaxation process prevails in Tb phthalocyanines. The present work clearly demonstrates that the selection of lanthanide ions is important to design single molecule magnets with a high performance.
Activation energies and the extended jump model: How temperature affects reorientation and hydrogen-bond exchange dynamics in water
Authors: Piskulich Zeke A. , Laage Damien , Thompson Ward H.
Published: August 2020

Hydrogen-bond exchanges drive many dynamical processes in water and aqueous solutions. The extended jump model (EJM) provides a quantitative description of OH reorientation in water based on contributions from hydrogen-bond exchanges, or jumps, and the “frame” reorientation of intact hydrogen-bond pairs. Here, we show that the activation energies of OH reorientation in bulk water can be calculated accurately from the EJM and that the model provides a consistent picture of hydrogen-bond exchanges based on molecular interactions. Specifically, we use the recently developed fluctuation theory for dynamics to calculate activation energies, from simulations at a single temperature, of the hydrogen-bond jumps and the frame reorientation, including their decompositions into contributions from different interactions. These are shown to be in accord, when interpreted using the EJM, with the corresponding activation energies obtained directly for OH reorientation. Thus, the present results demonstrate that the EJM can be used to describe the temperature dependence of reorientational dynamics and the underlying mechanistic details.
Allosteric regulation of thioesterase superfamily member 1 by lipid sensor domain binding fatty acids and lysophosphatidylcholine
Authors: Tillman Matthew C. , Imai Norihiro , Li Yue , Khadka Manoj , Okafor C. Denise , Juneja Puneet , Adhiyaman Akshitha , Hagen Susan J. , Cohen David E. , Ortlund Eric A.
Published: August 2020

Significance

Brown adipose tissue (BAT) burns fat to maintain body temperature through thermogenesis in mammals. Because heat production requires metabolizing large amounts of calories, increasing the activity of the tissue could treat obesity and related metabolic disorders. Recently, thioesterase superfamily member 1 (Them1) was identified to suppress thermogenesis, whereas deletion of Them1 enhanced the ability of BAT to burn fat and prevented diet-induced obesity. In this study, we show Them1 contains a lipid sensor that binds to fatty acids and lysophosphatidylcholine, which inversely regulate the activity of Them1. This lipid sensor allows for allosteric control of Them1 activity to regulate the burning of fat. Additionally, this study affirms a promising drug target to treat obesity and related disorders.
Phosphoglycolate salvage in a chemolithoautotroph using the Calvin cycle
Authors: Claassens Nico J. , Scarinci Giovanni , Fischer Axel , Flamholz Avi I. , Newell William , Frielingsdorf Stefan , Lenz Oliver , Bar-Even Arren
Published: August 2020

Significance

The Calvin cycle is the most important carbon fixation pathway in the biosphere. However, its carboxylating enzyme Rubisco also accepts oxygen, thus producing 2-phosphoglycolate. Phosphoglycolate salvage pathways were extensively studied in photoautotrophs but remain uncharacterized in chemolithoautotrophs using the Calvin cycle. Here, we study phosphoglycolate salvage in the chemolithoautotrophic model bacterium
Cupriavidus necator
H16. We demonstrate that this bacterium mainly reassimilates 2-phosphoglycolate via the glycerate pathway. Upon disruption of this pathway, a secondary route, which we term the malate cycle, supports photorespiration by completely oxidizing 2-phosphoglycolate to CO
2
. While the malate cycle was not previously known to metabolize 2-phosphoglycolate in nature, a bioinformatic analysis suggests that it may support phosphoglycolate salvage in diverse chemoautotrophic bacteria.
Impartiality and accuracy as a case in point while interpreting in a refugee context
Authors: Jiménez Ivars Amparo
Published: August 2020

This paper examines the fundamentals of professionalism focusing on the code of ethics as a pivotal parameter. Attention is paid to the difficulties of implementing two of the core principles of codes of ethics for interpreting in a refugee context: impartiality and accuracy. The aim of this article is to explore interpreters’ appreciation of these principles and self-identification with them versus actual observance in refugee settings. Ninety-six US-based interpreters completed a survey on self-perceptions regarding adherence to the principles and real actions performed. Findings show that a high number of interpreters do not comply with the principles despite having previously declared their full endorsement and self-identification with them. Impartiality presented more deviations than accuracy. Internal and external demands have proven to be stronger than adherence to the code. Calls to rethink and refine codes of ethics for interpreting in a refugee context are also presented.
Hopf link volume simplicity constraints in spin foam models
Authors: Assanioussi Mehdi , Bahr Benjamin
Published: August 2020

In this article we consider specific bivector geometries which arise in the large-spin limit of the extension of the Engle–Pereira–Rovelli–Livine spin foam model for quantum gravity by Kaminski, Kisielowski and Lewandowski. We address the implementation of volume simplicity constraints, which are required to ensure that a 4d metric can be reconstructed from the bivector geometry. We find that the necessary conditions are closely related, but not quite equal to the Hopf link volume simplicity constraints introduced in earlier works. We estimate the number of independent geometricity conditions for arbitrary bivector geometries, and find that they always agree with the number of Hopf links on the graph minus one, suggesting that the geometricity conditions can generically be formulated by deformation of the Hopf link volume simplicity constraints.
pygiftgenerator: a python module designed to prepare Moodle-based quizzes
Authors: Sáenz Jon , Gurtubay Idoia G , Izaola Zunbeltz , López Gabriel A
Published: August 2020

We present pygiftgenerator, a python module for systematically preparing a large number of numerical and multiple-choice questions for Moodle-based quizzes oriented to students’ formative evaluation. The use of the module is illustrated by means of examples provided with the code and drawn from different topics, such as mechanics, electromagnetism, thermodynamics and modern physics. The fact that pygiftgenerator relies on a well-established computer language, which allows functions to be combined and reused in order to solve complex problems, makes it a very robust tool. Simply by changing the input parameters, a large question bank with solutions to complex physical problems, can be generated. Thus, it is a powerful alternative to the calculated and multiple-choice questions which can be written directly in the Moodle platform. The module writes questions to be imported into Moodle and produces simple and human-readable ASCII output using the GIFT format, which enables html definitions for URLs for importing figures, or for simple text formatting (sub/superindices or Greek letters) for equations and units. This format also allows LaTeX and MathJax typing for complex equations.
Investigation of extreme ultraviolet spectra from highly charged holmium ions in 1
μ
m laser-produced plasmas
Authors: Wu Tao , Kawasaki Hiromu , Shimada Yuta , Higashiguchi Takeshi , O’Sullivan Gerry
Published: August 2020

Absolute intensity calibrated extreme ultraviolet spectra radiated by highly charged holmium (Ho) ions from 1 μm Nd:YAG laser generated plasmas in the 1–8 nm wavelength spectral range were measured and investigated. The spectral features show a broad structured continuum-like emission band, most prominent in the wavelength range 6–8 nm, which accounts for more than half of the emitted power. Assuming local thermodynamic equilibrium (LTE) in the laser produced plasmas and using the flexible atomic code and Cowan suite of codes, the wavelengths and LTE-gA values of unresolved transition arrays (UTAs) from E
1-contributing transition arrays 4p–4d, 4d–4f and super transition arrays such as 4p64d
k−14f + 4p54d
k+1–4p64d
k−24f2 + 4p44d
k+2 + 4p54d
k
4f and 4d10(5s5p)
k
4f
m−k
–4d9(5s5p)
k
4f
m−k+1 were calculated and shown to be responsible for the strongest observed spectral structure. Transitions between these excited to excited states are considered, since even if only weakly present, they will not be influenced by opacity effects unlike resonance transitions involving ground configurations. Another two intense continuous emission bands at 3–6 nm and 2–3 nm that dominate the spectra in the shorter wavelength range mainly arise from 4d–5p, 4d5s–4d5s5p, 4f–5g, 4f5s–4f5s5g and 4d–5f, 4d5s–4d5s5f, 4p–5s transitions. Spectral line shape parameters of Gaussian fits to the LTE-gA weighted radiation spectra of each Ho ion were given, enabling direct explanation of recorded spectra. Based on the LTE-gA UTAs formalism parameters, reasonable agreement is obtained between the synthetic spectrum and experimental result enabling some of the observed spectral features to be identified.
Benchmark calculations of ro-vibrational spectrum of HeH
−
and its isotopologues
Authors: Palikot Ewa , Stanke Monika , Adamowicz Ludwik
Published: August 2020

Benchmark variational calculations of the Born–Oppenheimer potential energy curve (PEC) performed with explicitly correlated all-electron Gaussian functions with shifted centers are presented. The PEC energies include the leading relativistic and quantum-electrodynamics corrections and the first-order corrections due to adiabatic effects. The PEC is used to calculate the ro-vibrational spectra for HeH− and its isotopologues. The results show that these systems are marginally stable and have two to four bound vibrational levels and, for each vibrational level, a few bound rotational levels lying below the dissociation threshold. This indicates a possibility of detecting the HeH− anion in the laboratory and, perhaps, even in the interstellar space.
Ultra-sensitive anomalous Hall effect sensors based on Cr-doped Bi2Te3 topological insulator thin films
Authors: Ning Jiai , Zhao Yafei , Chen Zhendong , Sun Yizhe , Gao Qinwu , Chen Yequan , Kanagaraj Moorthi , Zhang Junran , He Liang
Published: August 2020

The observation of anomalous Hall effect (AHE) in magnetically doped topological insulators brings a new candidate of Hall sensor with low power consumption. In this work, the transport properties and the sensitivity of AHE sensors based on Cr-doped Bi2Te3 thin films were studied. Obvious AHEs induced by ferromagnetic ordering were presented in all Cr
x
Bi2-x
Te3 sensors. At the optimized doping concentration of x= 0.09, a high sensitivity of 6625 Ω T−1 was achieved, which has increased by 2.5 times compared to the highest reported one in Cr-doped Bi2Te3. More importantly, a considerable sensitivity of 4082 Ω T−1 can be obtained up to 20 K, which implies a higher working temperature than other reports. Our findings suggest Cr-doped Bi2Te3 sensor could be a good candidate for highly sensitive AHE sensors and reveal the extraordinary potential of magnetic TIs in the applications of field detection.
Metal-insulator-metal thin film stack: flux enhancement due to coupling of surface plasmon polariton with wave guide modes
Authors: Raşeev Georges , Achlan Moustafa
Published: August 2020

A theoretical study is presented of the dispersion of surface plasmon polariton (SPP) and wave guide (WG) modes of a metal-insulator-metal (MIM) thin film stack. We study the dispersion of the reflectance and of the transmitted flux, originating from a local excitation source, of an asymmetric MIM air-Au-SiO2-Au-Ti-glass material system in the infrared and visible spectral region for a wide range of SiO2 and gold thicknesses,

d

S
i
O

2

and

d

A
u

. In comparison to reference stacks of air-Au-glass or air-SiO2-glass, between 1.4 and 2.0 eV, the transmitted flux intensity is enhanced 12 or 25 times, in the emission direction of the in-plane wave vector

k
ρ

/

k
0

≈

1.05 and for a thickness of

d

S
i
O

2

∈

[300–700] nm, respectively. This enhancement is attributed to the coupling, through the avoided crossings, between the SPP

a
i
r

and WG modes. As the fields of the SPP

a
i
r

and WG modes are located in different regions of space the enhancement is nearly independent of the number of nodes in the WG mode. In summary we have identified sets of parameters giving rise to the observables enhancement. Therefore the present MIM thin film stack is a simple and a versatile system for the use in applications.
Attenuation correction for human PET/MRI studies
Authors: Catana Ciprian
Published: August 2020

Attenuation correction has been one of the main methodological challenges in the integrated positron emission tomography and magnetic resonance imaging (PET/MRI) field. As standard transmission or computed tomography approaches are not available in integrated PET/MRI scanners, MR-based attenuation correction approaches had to be developed. Aspects that have to be considered for implementing accurate methods include the need to account for attenuation in bone tissue, normal and pathological lung and the MR hardware present in the PET field-of-view, to reduce the impact of subject motion, to minimize truncation and susceptibility artifacts, and to address issues related to the data acquisition and processing both on the PET and MRI sides. The standard MR-based attenuation correction techniques implemented by the PET/MRI equipment manufacturers and their impact on clinical and research PET data interpretation and quantification are first discussed. Next, the more advanced methods, including the latest generation deep learning-based approaches that have been proposed for further minimizing the attenuation correction related bias are described. Finally, a future perspective focused on the needed developments in the field is given.
Electronegative magnetized plasma sheath properties in the presence of non-Maxwellian electrons with a homogeneous ion source
Authors: Basnet Suresh , Patel Amit , Khanal Raju
Published: August 2020

The three-fluid model was employed to study electronegative magnetized plasma sheath properties in the presence of non-Maxwellian electrons. The Bohm condition for the electronegative magnetized plasma was extended in the presence of a homogeneous ionization source term and an ion-neutral collision force. The effect of the following physical parameters: the degree of non-Maxwellian electrons, ion-neutral collisions, obliqueness of the magnetic field and source frequency on the plasma sheath parameters are numerically analyzed and presented. It was found that the magnitude of the potential increased in all cases and hence the velocity of the ions increased towards the wall. The plasma sheath parameters were not significantly varied about 2λ

De
from the presheath—sheath interface, but after that, the sheath parameters abruptly changed towards the wall. The effect of ion-neutral collisions and the obliqueness of the magnetic field on the potential distribution, net charge density and drift velocity of ions are discussed. Furthermore, a comparison of plasma sheath characteristics with and without the ion source term is systematically presented.
Magnetic flux in stacks of superconducting tapes of different architecture
Authors: Harca I M , Machaj K , Tomkow L , Glowacki B A
Published: August 2020

Stacks of superconducting tapes nowadays have multiple applications and many new modifications are currently considered to enhance their beneficial properties. We have studied the field trapping in stacks of commercial superconducting tapes with different configurations. Experimental and numerical analyses were performed. The superconducting stacks were magnetized to act as powerful permanent magnets using pulsed field magnetization and field cooling at 77 K. The configurations include a basic stack made of layered tapes, a stack interlayered with ferromagnetic material, a sectioned stack made of thin tapes and a shielded basic stack.

The present study shows that, in terms of total trapped flux, the basic stack performs best, closely followed by the shielded stack. No significant positive effect due to the presence of ferromagnetic layers was found in the studied configuration. The sectioned stack is the worst according to every analysed criterion. The possibility of application of the analysed modification is discussed.
Nonlinear radiation oscillator theory for symmetric and anti-symmetric damping graphene coupled metamaterials
Authors: He Zhihui , Li Chunjiang , Li Zhenxiong , Xue Weiwei , Cui Wei
Published: August 2020

We develop a novel nonlinear radiation oscillator theory, which can describe nonlinear optical responses in symmetric and anti-symmetric damping graphene coupled metamaterials. An ultra-high quality factor of induced transparency can be realized in the proposed model. The results show that the spectral response and quality factor can be effectively tuned by the resonant detuning, the phase difference, the damping factor as well as the field intensity of the pump light. Moreover, the quality factor of induced transparency is increased by more than 60 times when the field intensity of the pump light and the damping factor are changed. Especially, the single induced transparency window splits into double induced transparency windows as the damping factors of dark mode and bright mode show anti-symmetric damping case. These results may pave the way for designing the high performance of nano-optical devices in terahertz.
Quantification of single-strand DNA by sequence-specific counting in capillary flow cytometry
Authors: Yoo Hee-Bong , Lee Chaeeun , Hong Kee-Suk , Park Sang-Ryoul , Yang Inchul
Published: August 2020

In this study, we report an approach to achieve sequence-specific counting of single DNA molecules, which is required for more versatile applications of the previously reported absolute DNA quantification technique based on flow cytometric DNA single molecule counting. While using the same capillary-based flow cytometric setup, fluorescence activation of a target DNA was made with a number of fluorescent oligonucleotide probes of complementary sequences to that of a target DNA. The feasibility of the proposed approach was tested with 7 kb single-strand M13 DNA as the target DNA for sequence specific counting for quantification. Sample preparation, the number of fluorescent oligonucleotide probes, and hybridization conditions mainly matter for the performance of the proposed method. Using a set of 30 sequence-specific fluorescent probes with a selected hybridization buffer, acceptable performance was confirmed through comparison with other conventional methods such as digital polymerase chain reaction (dPCR), UV spectrophotometry, and deoxyribonucleoside monophosphate analysis by mass spectrometry. Proven comparability to the dPCR method confirmed the feasibility of the proposed approach. With further improvement in instrumentation, the proposed method is expected to become established as a reference measurement procedure for sequence-specific quantification of nucleic acids working under a uniquely straightforward measurement principle.
Calibration method and photon flux influences tiled flat-panel photon counting detector image uniformity in computed tomography
Authors: Inkinen S.I. , Juntunen M.A.K. , Kotiaho A. , Nieminen M.T.
Published: August 2020

The aim of this study is to compare how different calibration methods influence the image quality of photon-counting detector computed tomography (PCD-CT) at high and low photon fluxes. We investigate the performance of flat-field correction, signal-to-equivalent thickness calibration (STC), and polynomial correction (PC) methods using polymethyl methacrylate (PMMA) and iron as calibration materials. Two different cylindrical imaging phantoms containing contrast targets were scanned: an agar phantom and a phantom consisting of titanium hip implant embedded in agar. The scans were acquired using 120 kVp, and the energy thresholds of the PCD were set at 10 keV and 60 keV to obtain low energy (10–60 keV), high energy (60–120 keV) and total energy images (10–120 keV). Additionally, virtual monochromatic images (VMIs) with energies between 60–180 keV with 20 keV increments were generated from PC data. The reconstructions were made using filtered back projection, and image quality was assessed by evaluating image noise, contrast-to-noise ratio (CNR), and image uniformity. Overall, STC with PMMA as calibration material yielded the best image quality in terms of CNR and uniformity. Flat-field correction produced uniform reconstruction at low photon flux, but the performance degraded substantially at high flux. STC with iron as calibration material did not improve the reconstructions of the titanium hip implant. The beam hardening effects arising from metal were reduced when the VMI energy was increased while the CNR evaluated from agar phantom decreased with increasing energy of the VMI. Over the methods investigated, STC with PMMA was the most optimal calibration method for PCD-CT, yielding excellent image uniformity with both photon flux conditions.
Autophagy machinery promotes the chaperone-mediated formation and compartmentalization of protein aggregates during appressorium development by the rice blast fungus
Authors: Rogers Audra Mae , Egan Martin John
Published: August 2020

The fungus Magnaporthe oryzae causes rice blast disease, which destroys enough rice annually to feed 60 million people. M. oryzae forms a specialized infection cell, which it uses to break into host tissue. Here we investigate how M. oryzae spatially and temporally manages stress-induced protein damage during infection-related development.
1. Why ghetto?
Authors: Cheyette Bryan
Published: August 2020

‘Why ghetto?’ traces the idea of the ghetto to medieval and early modern Western and Central Europe. Before there were ghettos, there were Jewish quarters. Larger Jewish quarters were part of a region’s economic life and were the model for early modern ghettos. In the 16th century, with most Jews in Western Europe expelled, ghetto living became compulsory in many northern and central Italian urban areas. By the 17th century, the word ‘ghetto’ shifted from a noun to an adjective and was used in most official Italian documents. During the Holocaust, the Nazis used earlier ideas of the medieval ghetto to hide their policies of forced segregation and racial genocide. Twentieth-century African-Americans in northern cities adopted the language of the ghetto to describe their neighbourhoods which, due to racist housing associations and discriminatory local authorities, remained segregated for most of the 20th century. Does the idea of the ghetto mean the same thing for today’s African-Americans as it did for earlier Jewish communities?
3. Ghettos of the imagination
Authors: Cheyette Bryan
Published: August 2020

With the destruction of ghetto gates by Napoleon Bonaparte’s army, actual ghettos were replaced by imagined ones. ‘Ghettos of the imagination’ explores 19th-century ghetto literature. This literature crossed borders—for example, the exportation of British writer Israel Zangwill’s bestselling fiction to America. Late 19th-century America saw a huge influx of Eastern European refugees fleeing pogroms, leading to the establishment of large urban Jewish communities in its cities. Early French and German ghetto literature portrayed the ghetto as romantic and culturally rich, and associated it with the past. By the end of the 19th century, the free-floating ghetto had moved to the present, across to America, and from Western Europe to Eastern Europe.
4. Nazism and the ghetto
Authors: Cheyette Bryan
Published: August 2020

‘Nazism and the ghetto’ describes how the idea of the ghetto persisted alongside actual segregation during the Holocaust, with persecuted Jews seeing historic ghettos as part of their experience of an unprecedented genocide. The Łódź Ghetto included a powerful workforce under the leadership of Chaim Rumkowski which contributed to the German economy. The Warsaw Ghetto, which was larger, more diffuse, and dependent on a black market, became a site of uprising and revolt. The Nazis exploited the multiple meanings of ‘ghetto’ to portray Theresienstadt, a ‘model’ ghetto, as particularly benign for an international audience. There were many hundreds of Nazi ghettos during the war—some large, some small, some short-lived, and some lasting for years. All of them contributed to the Holocaust.
Disputing
Authors: Williamson Timothy
Published: August 2020

What has combat to do with the pursuit of truth? ‘Disputing’ explores the role of debate in philosophy, in which the question-and-answer session is as important as the lecture. The debate can be constructive as well as combative. There is a danger that quieter voices will be drowned out by bluster. Legal disputes are a useful comparison—two sides are not always equal but are more effective than a single magistrate. From Plato onwards, the spoken or written dialogue was an important philosophical tool, and medieval scholars formalized debate into logic games. Disputes can be challenging but preferable to environments where criticism is discouraged.
Doing thought experiments
Authors: Williamson Timothy
Published: August 2020

Reasonable true belief without knowledge is possible, but knowledge is not only justified true belief—so what is it? ‘Doing thought experiments‘ explores how human beings use their imagination and intuition to solve philosophical problems in imaginary scenarios. Thought experiments have played a major role in recent moral philosophy. Sometimes thought experiments are enacted in real life, whereas some can only be imagined. The challenge is to come up with a scenario interesting enough to prove. Through imagining something fully, we know that it is possible, but imagination is not infallible. What if we all gave the same verdict on a thought experiment, but were wrong?
2. The dawn of ecology
Authors: Ghazoul Jaboury
Published: August 2020

‘The dawn of ecology’ introduces the Greek writer Theophrastus and his discovery that plants flourish in places suited to their intrinsic attributes. The word ‘ecosystem’ was coined by 20th-century botanist Andrew Tansley, who argued that organisms and their environment should be considered together. Charles Elton created the ‘pyramid of numbers’, with producers at the bottom and primary consumers at the top. Georgy Gause discovered competition among species—if two organisms in competition for the same resource were put together, one would wipe the other out. Mathematical and scientific predictive models would become useful in unstable climate conditions, allowing specialists to identify potential tipping points.
6. Applied ecology
Authors: Ghazoul Jaboury
Published: August 2020

‘Applied ecology’ looks at the application of ecological theories in modelling renewable resources and population dynamics, particularly in relation to species we wish to control or preserve. The collapse of cod fisheries shows the consequences when the bottom of the food chain (changes in phytoplankton) impacts the top. Changes in climate and fire regimes in America’s forests suggests current models may no longer be sustainable in future. How do species mixes help alleviate pressure from pests or pathogens? Successes in the lab have failed in the field, or not taken into account alternative problems that arise from manipulating the ecosystem. Biological and pest control strategies require a holistic approach.
7. Ecology in culture
Authors: Ghazoul Jaboury
Published: August 2020

The science of ecology is often conflated with environmentalism. ‘Ecology in culture’ looks at the transfer of ecological insights to moral and political fields. Has ecological science enabled us to develop an ecological conscience that will help the planet withstand unprecedented environmental challenges? Transformative movements include Gaia Theory (the idea of the earth as a living, self-regulating organism); Deep Ecology (a movement that disregards a human-centred approach); Cultural Ecology (which advocates for our environment’s ability to sustain culture); and Sacred Ecology (a new perspective on how to interact with nature and the elements. To restore environmental health, should we rebuild a cultural ecology?
Approximating posteriors with high-dimensional nuisance parameters via integrated rotated Gaussian approximation
Authors: van den Boom W , Reeves G , Dunson D B
Published: August 2020

Posterior computation for high-dimensional data with many parameters can be challenging. This article focuses on a new method for approximating posterior distributions of a low- to moderate-dimensional parameter in the presence of a high-dimensional or otherwise computationally challenging nuisance parameter. The focus is on regression models and the key idea is to separate the likelihood into two components through a rotation. One component involves only the nuisance parameters, which can then be integrated out using a novel type of Gaussian approximation. We provide theory on approximation accuracy that holds for a broad class of forms of the nuisance component and priors. Applying our method to simulated and real datasets shows that it can outperform state-of-the-art posterior approximation approaches.
Aberrant striatal dopamine links topographically with cortico-thalamic dysconnectivity in schizophrenia
Authors: Avram Mihai , Brandl Felix , Knolle Franziska , Cabello Jorge , Leucht Claudia , Scherr Martin , Mustafa Mona , Koutsouleris Nikolaos , Leucht Stefan , Ziegler Sibylle , Sorg Christian
Published: August 2020

Aberrant dopamine function in the dorsal striatum and aberrant intrinsic functional connectivity (iFC) between distinct cortical networks and thalamic nuclei are among the most consistent large-scale brain imaging findings in schizophrenia. A pathophysiological link between these two alterations is suggested by theoretical models based on striatal dopamine’s topographic modulation of cortico-thalamic connectivity within cortico-basal-ganglia-thalamic circuits. We hypothesized that aberrant striatal dopamine links topographically with aberrant cortico-thalamic iFC, i.e. aberrant associative striatum dopamine is associated with aberrant iFC between the salience network and thalamus, and aberrant sensorimotor striatum dopamine with aberrant iFC between the auditory-sensorimotor network and thalamus. Nineteen patients with schizophrenia during remission of psychotic symptoms and 19 age- and sex-comparable control subjects underwent simultaneous fluorodihydroxyphenyl-l-alanine PET (18F-DOPA-PET) and resting state functional MRI (rs-fMRI). The influx constant kicer based on 18F-DOPA-PET was used to measure striatal dopamine synthesis capacity; correlation coefficients between rs-fMRI time series of cortical networks and thalamic regions of interest were used to measure iFC. In the salience network-centred system, patients had reduced associative striatum dopamine synthesis capacity, which correlated positively with decreased salience network-mediodorsal-thalamus iFC. This correlation was present in both patients and healthy controls. In the auditory-sensorimotor network-centred system, patients had reduced sensorimotor striatum dopamine synthesis capacity, which correlated positively with increased auditory-sensorimotor network-ventrolateral-thalamus iFC. This correlation was present in patients only. Results demonstrate that reduced striatal dopamine synthesis capacity links topographically with cortico-thalamic intrinsic dysconnectivity in schizophrenia. Data suggest that aberrant striatal dopamine and cortico-thalamic dysconnectivity are pathophysiologically related within dopamine-modulated cortico-basal ganglia-thalamic circuits in schizophrenia.
Neighborhood Deprivation and Racial/Ethnic Disparities in Human Immunodeficiency Virus Viral Suppression: A Single-center, Cross-sectional Study in the United States Midwest
Authors: Khazanchi Rohan , Sayles Harlan , Bares Sara H , Swindells Susan , Marcelin Jasmine R
Published: August 2020

Combating disparities is a crucial goal of ongoing efforts to end the human immunodeficiency virus (HIV) epidemic. In a multivariable analysis of a cohort in the Midwestern United States, racial/ethnic disparities in HIV viral suppression were no longer robust after accounting for other sociodemographic factors. Neighborhood deprivation and low income were independently inversely associated with viral suppression.
A blubber gene expression index for evaluating stress in marine mammals
Authors: Pujade Busqueta Laura , Crocker Daniel E , Champagne Cory D , McCormley Molly C , Deyarmin Jared S , Houser Dorian S , Khudyakov Jane I
Published: August 2020

Evaluating the impacts of anthropogenic disturbance on free-ranging marine mammal populations, many of which are in decline, requires robust diagnostic markers of physiological stress and health. However, circulating levels of canonical ‘stress hormones’ such as glucocorticoids, which are commonly used to evaluate animal health, do not capture the complexity of species-specific responses and cannot be easily measured in large, fully aquatic marine mammals. Alternatively, expression of stress-responsive genes in hormone target tissues such as blubber, the specialized subcutaneous adipose tissue that can be manually or remotely sampled from many marine mammals, may be a more informative and sensitive indicator of recent (within 24 h) exposure to stressors. We previously identified genes that were upregulated in the inner blubber of juvenile northern elephant seals during experimental stimulation of the hypothalamic–pituitary–adrenal axis. In this study, we measured baseline expression levels of a subset of these genes in inner blubber of unmanipulated juvenile elephant seals of varying physiological states and correlated them with other stress markers (body condition index, corticosteroid and thyroid hormone levels). Expression of 10 genes, including those associated with lipid metabolism (ACSL1, HMGCS2, CDO1), redox homeostasis (GPX3), adipokine signaling (ADIPOQ), lipid droplet formation (PLIN1, CIDEA) and adipogenesis (DKK1, AZGP1, TGFBI), was described by three principal components and was associated with cortisol and thyroid hormone levels. Significantly, baseline gene expression levels were predictive of circulating hormone levels, suggesting that these markers may be potential indicators of exposure to stressors in marine mammal species that are inaccessible for blood sampling. A similar approach may be used to identify species-specific stress markers in other tissues that can be sampled by remote biopsy dart from free-ranging marine mammals, such as outer blubber and skin.
Safety of patients and providers in lung cancer surgery during the COVID-19 pandemic
Authors: Chang Stephanie H , Zervos Michael , Kent Amie , Chachoua Abraham , Bizekis Costas , Pass Harvey , Cerfolio Robert J
Published: August 2020

OBJECTIVES

The coronavirus disease 2019 (COVID-19) pandemic has resulted in patient reluctance to seek care due to fear of contracting the virus, especially in New York City which was the epicentre during the surge. The primary objectives of this study are to evaluate the safety of patients who have undergone pulmonary resection for lung cancer as well as provider safety, using COVID-19 testing, symptoms and early patient outcomes.

METHODS

Patients with confirmed or suspected pulmonary malignancy who underwent resection from 13 March to 4 May 2020 were retrospectively reviewed.

RESULTS

Between 13 March and 4 May 2020, 2087 COVID-19 patients were admitted, with a median daily census of 299, to one of our Manhattan campuses (80% of hospital capacity). During this time, 21 patients (median age 72 years) out of 45 eligible surgical candidates underwent pulmonary resection—13 lobectomies, 6 segmentectomies and 2 pneumonectomies were performed by the same providers who were caring for COVID-19 patients. None of the patients developed major complications, 5 had minor complications, and the median length of hospital stay was 2 days. No previously COVID-19-negative patient (n = 20/21) or healthcare provider (n = 9: 3 surgeons, 3 surgical assistants, 3 anaesthesiologists) developed symptoms of or tested positive for COVID-19.

CONCLUSIONS

Pulmonary resection for lung cancer is safe in selected patients, even when performed by providers who care for COVID-19 patients in a hospital with a large COVID-19 census. None of our patients or providers developed symptoms of COVID-19 and no patient experienced major morbidity or mortality.
Surgical treatment of prosthetic mechanical valve thrombosis with the aid of high-flow CO2
Authors: Moscarelli Marco , Nasso Giuseppe , Vite Giuseppe , Speziale Giuseppe
Published: August 2020

The surgical treatment of prosthetic mechanical valve thrombosis involves redo valve replacement and removal of the thrombi layers. The hinges and near-hinge areas of the bi-leaflet mechanical valve are a ‘stagnation area’ where blood flow is typically unsteady and can give rise to thrombi; however, these zones are not easily accessed with surgical instruments. Here, we present a case in which high-flow CO2 was used to facilitate the removal of microthrombi in the stagnation area around a prosthetic mechanical valve.
Testing the consistency of preferences in discrete choice experiments: an eye tracking study
Authors: Segovia Michelle S , Palma Marco A
Published: August 2020

A within-subjects experiment with eye tracking was implemented to test the consistency of preferences over three repeated choice experiments. The empirical results indicate that after changing the position of the same alternatives in the choice set, participants were consistent with their choices 69 per cent of the time. Moreover, after reverting back to the identical original positions of the alternatives but randomising the order of the choice sets, individuals’ choices were consistent 67 per cent of the time. Eye tracking data revealed that subjects’ visual attention towards the product attributes was also consistent over the sequence of choices. The robustness of these results was further demonstrated by using random parameters models with flexible mixing distributions to calculate willingness-to-pay for the product attributes and compare its consistency across choice experiments.
Calculated Ageism: Generational Sacrifice as a Response to the COVID-19 Pandemic
Authors: Barrett Anne E , Michael Cherish , Padavic Irene
Published: August 2020

Objectives

Popular responses to the pandemic illustrate ageism’s pervasiveness and the extent of collective acquiescence to its newest expressions. We explore these themes by analyzing Twitter reactions to “calculated ageism”—a term we use to refer to a political figure’s edict that older adults should sacrifice their lives if it will mitigate the pandemic’s economic damage to younger people.

Method

Using thematic analysis, we examine tweets (n = 188) responding to Texas Lt. Governor Dan Patrick’s March 23, 2020, statement that encouraged generational self-sacrifice. Themes that emerged included positions of support or opposition and tweeters’ critiques.

Results

The large majority of tweets—90%—opposed calculated ageism, while only 5% supported it and 5% conveyed no position. Opposition centered on moral critiques, political-economic critiques, assertions of older adults’ worth, and public health arguments. Support centered on individual responsibility and patriotism.

Discussion

While prior research reveals ageism’s entrenchment in popular culture, our study finds that it has limits and identifies the reasons underlying them. The most common reasons for opposing calculated ageism center on its immorality and on its privileging of the economic interests of the powerful few over the many, patterns suggesting that the boundaries of ageism are influenced by core beliefs about fairness. They also are shaped by a bedrock conviction that older lives have value. This intergenerational solidarity could be leveraged to reduce ageism during the pandemic and beyond.
Plant Variety Rights Protection and Essentially Derived Varieties: A Fresh Proposal to Untie the Gordian Knot
Authors: Bostyn Sven J R
Published: August 2020

The concept of essentially derived varieties (EDVs) under the UPOV Convention 1991 has presented many challenges both to the UPOV and users of the system. The concept of EDVs is not only framed in rather difficult language in the statute, it has proven equally difficult to apply. Moreover, gaining consensus on the exact interpretation of the concept, left to be implemented later on by courts and/or guidelines, has been an equally challenging task due to a lack of clarity in the provisions of the UPOV 1991 Convention. This article constitutes a novel and original contribution to the research that has been carried out in the area of EDVs. Novel approaches are necessary to untie the EDV knot. The approaches presented here are inspired by other areas of (intellectual property) law. A careful study of the solutions presented herein demonstrate that at least some of them can effectively put an end to at least some of the deadlock and legal uncertainty surrounding the EDV concept. It is hoped that this contribution and the approaches it puts forward can be the catalyst for a new debate, which is not only necessary but also long overdue.