bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical computations of geometric ergodicity for stochastic dynamics
Authors: Li Yao , Wang Shirou
Published: October 2020

A probabilistic approach to compute the geometric convergence rate of a stochastic process is introduced in this paper. The goal is to quantitatively compute both the upper and lower bounds for rate of the exponential convergence to the stationary distribution of a stochastic dynamical system. By applying the coupling method, we derive an algorithm which does not rely on the discretization of the infinitesimal generator. In this way, our approach works well for many high-dimensional examples. We apply this algorithm to the random perturbations of both iterative maps and differential equations. We show that the rate of geometric ergodicity of a random perturbed system can, to some extent, reveal the degree of chaoticity of the underlying deterministic dynamics. Various SDE models including the ones with degenerate noise or living on the high-dimensional state space are also explored.
Determination of plasma parameters by spectral line broadening in an electrosurgical argon plasma
Authors: Hillebrand Bastian , Iglesias Enrique , Gibson Andrew R , Bibinov Nikita , Neugebauer Alexander , Enderle Markus , Awakowicz Peter
Published: October 2020

An electrosurgical argon plasma with a 5% admixture of molecular hydrogen is studied in order to investigate time averaged plasma parameters by optical emission spectroscopy (OES). Electron densities in the range of 1015–1016 cm−3 are determined from the Stark broadening of the time averaged line profiles of the Balmer-α and -β emission lines of hydrogen. A two-profile fit corresponding to regions of different electron densities is found to provide a better representation of the line broadening than a single profile fit. This is consistent with time resolved ICCD imaging, acquired with 150 ns time resolution, that shows strong radial gradients in the plasma emission and the asymmetry produced by the discharge arrangement. Gas temperatures are determined using two different methods. Firstly, simulated spectra for different rotational temperatures are fitted to the measured N2(C-B, 0-1) emission band originating from ambient air diffusion into the argon/hydrogen gas flow. From the best fit, rotational temperatures between 1500 K and 1800 K are inferred. These measurements are in good agreement with those inferred by the second method, which is based on the collisional broadening of the emission lines of neutral argon at 750 nm and 751 nm. This latter method may be useful for the measurement of gas temperatures when the device is used inside hollow organs during endoscopic or laparoscopic interventions, where air mixing will be limited. Therefore, the results of this study are highly relevant to applications of these devices, e.g. for controlling tissue effects and the avoidance of excessive heating.
Determination of charge-compensated C
3υ (II) centers for Er3+ ions in CdF2 and CaF2 crystals*
Authors: Chai Rui-Peng , Hao Dan-Hui , Gao Dang-Li , Pang Qing
Published: October 2020

A unified theoretical method is established to determine the charge-compensated C
3v
(II) centers of Er3+ ions in CdF2 and CaF2 crystals by simulating the electron paramagnetic resonance (EPR) parameters and Stark energy levels. The potential (Er3+–F−–

O
4

2
−

) and (Er3+–

F
7
−

–O2–) structures for the C
3v
(II) centers of Er3+ ions in CdF2 and CaF2 crystals are checked by diagonalizing 364 × 364 complete energy matrices in the scheme of superposition model. Our studies indicate that the C
3v
(II) centers of Er3+ ions in CdF2 and CaF2 may be ascribed to the local (Er3+–F−–

O
4

2
−

) structure, where the upper ligand ion F− undergoes an off-center displacement by ΔZ ≈ 0.3 Å for CdF2 and ΔZ ≈ 0.29 Å for the CaF2 along the C
3 axis. Meanwhile, a local compressed distortion of the

(

ErFO

4

)

6
−

cluster is expected to be ΔR ≈ 0.07 Å for CdF2:Er3+ and ΔR ≈ 0.079 Å for CaF2:Er3+. The considerable g-factor anisotropy for Er3+ ions in each of both crystals is explained reasonably by the obtained local parameters. Furthermore, our studies show that a stronger covalent effect exists in the C
3v
(II) center for Er3+ in CaF2 or CaF2, which may be due to the stronger electrostatic interaction and closer distance between the central Er3+ ion and ligand O2– with the (Er3+–F−–

O
4

2
−

) structure.
CCSD(T) study on the structures and chemical bonds of AnO molecules (An = Bk–Lr)*
Authors: Sun Xiyuan , Yin Pengfei , Wang Kaiming , Jiang Gang
Published: October 2020

The molecular geometries and dissociation energies of AnO (An = Bk–Lr) molecules were first obtained at the coupled-cluster single-, double-, and perturbative triple-excitations [CCSD(T)] level of theory. Four hybrid functionals, B3LYP, M06-2X, TPSSh, and PBE0, were also employed in the calculations for the sake of comparison. In comparison of the CCSD(T) results, B3LYP, TPSSh, and PBE0 functionals can obtain more appropriate results than M06-2X and MP2. The analyses on molecular orbitals show that the 7s, 6d, and 5f atomic orbitals of actinide (An) atoms participate in the bonding of An–O bonds. The partial covalent nature between An and O atoms is revealed by QTAIM analyses.
R-branch high-lying transition emission spectra of SbNa molecule*
Authors: Luo Chun-Run , Fan Qun-Chao , Fan Zhi-Xiang , Fu Jia , Ma Jie , Li Hui-Dong , Xu Yong-Gen
Published: October 2020

The calculation results of the R-branch transition emission spectra of (0–0) band of the A
2 1 → X
2 1 transition system of SbNa molecule are presented in this paper. These R-branch high-lying transitional emission spectral lines are predicted by using the difference converging method (DCM). Our results show excellent agreement between DCM spectral lines and the experimental values, and the deviations are controlled within 0.0224 cm−1. What is more, based on the principle of over-determined linear equations, the prediction error is quantified in this work, which provides reliable theoretical support for our predicted DCM calculations. This work provides a lot of useful information for understanding the microstructure of SbNa molecule.
Modeling and analysis of car-following behavior considering backward-looking effect*
Authors: Ma Dongfang , Han Yueyi , Qu Fengzhong , Jin Sheng
Published: October 2020

The car-following behavior can be influenced by its driver’s backward-looking effect. Especially in traffic congestion, if vehicles adjust the headway by considering backward-looking effect, the stability of traffic flow can be enhanced. A model of car-following behavior considering backward-looking effect was built using visual information as a stimulus. The critical stability conditions were derived by linear and nonlinear stability analyses. The results of parameter sensitivity analysis indicate that the stability of traffic flow was enhanced by considering the backward-looking effect. The spatiotemporal evolution of traffic flow of different truck ratios and varying degrees of backward-looking effect was determined by numerical simulation. This study lays a foundation for exploring the complex feature of car-following behavior and making the intelligent network vehicles control rules more consistent with human driver habits.
Broadband absorption enhancement with ultrathin MoS2 film in the visible regime*
Authors: Wu Jun
Published: October 2020

The broadband absorption enhancement effect in ultrathin molybdenum disulfide (MoS2) films is investigated. It is achieved by inserting the MoS2 film between a dielectric film and a one-dimensional silver grating backed with a silver mirror. The broadband absorption enhancement in the visible region is achieved, which exhibits large integrated absorption and short-circuit current density for solar energy under normal incidence. The optical properties of the proposed absorber are found to be superior to those of a reference planar structure, which makes the proposed structure advantageous for practical photovoltaic application. Moreover, the integrated absorption and short-circuit current density can be maintained high for a wide range of incident angles. A qualitative understanding of such broadband absorption enhancement effect is examined by illustrating the electromagnetic field distribution at some selected wavelengths. The results pave the way for developing high-performance optoelectronic devices, such as solar cells, photodetectors, and modulators.
On the 12C Hoyle state gamma decay
Authors: Cardella G. , Favela F. , Martorana N.S. , Acosta L. , Auditore L. , Camaiani A. , De Filippo E. , De Luca S. , Gelli N. , Geraci E. , Gnoffo B. , Guazzoni C. , Marín-Lámbarri D.J. , Lanzalone G. , Maiolino C. , Nannini A. , Pagano A. , Pagano E.V. , Papa M. , Pirrone S. , Politi G. , Pollacco E. , Quattrocchi L. , Rizzo F. , Russo A. D. , Russotto P. , Santonocito D. , Sicari V. , Trifirò A. , Trimarchi M.
Published: October 2020

The γ-decays of 12C excited levels (the Hoyle state 0+ at 7.65 MeV and the 9.64 MeV 3) are essential for its production in the universe. We present here a new attempt to precisely measure such γ-decay probabilities. The measurement was performed at INFN-LNS in Catania using the 4π CHIMERA multidetector. In order to measure these low probability decay-channels we performed 4-fold coincidence measurements. The 12C target nuclei were excited by using a beam of 64 MeV α-particles produced by the Superconducting Cyclotron (CS) of INFN-LNS. The scattered α-particles and the 12C recoils were detected and identified by? E-E and ToF methods using CHIMERA telescopes. The two emitted γ-rays in the decay chain were detected and identified by using the second stage of the telescopes, CsI(Tl) scintillators, by means of fast-slow and rise time techniques. Kinematics and energy-momentum conservation laws were used to constrain the data analysis. Also the 3-α decay channel probability was measured. Such a simultaneous measurement of all known decay channels was useful to reduce the systematic errors. Preliminary results of the data analysis are reported.
Nucleosynthesis in early rotating massive stars and chemical composition of CEMP stars
Authors: Choplin A , Hirschi R
Published: October 2020

The first massive stars triggered the onset of chemical evolution by releasing the first metals (elements heavier than helium) in the Universe. The nature of these stars and how the early chemical enrichment took place is still largely unknown. Rotational-induced mixing in the stellar interior can impact the nucleosynthesis during the stellar life of massive stars and lead to stellar ejecta having various chemical compositions. We present low and zero-metallicity 20, 25 and 40 M⊙ stellar models with various initial rotation rates and assumptions for the nuclear reactions rates. With increasing initial rotation, the yields of light (from ∼ C to Al) and trans-iron elements are boosted. The trans-iron elements (especially elements heavier than Ba) are significantly affected by the nuclear reaction uncertainties. The chemical composition of the observed CEMP (carbon-enhanced metal-poor) stars CS29528-028 and HE0336+0113 are consistent with the chemical composition of the material ejected by a fast rotating 40 M⊙ model.
Software defined radio for Schottky analysis in storage rings
Authors: Dmytriiev D. , Sanjari M. S. , Litvinov Yu. A. , Stöhlker Th.
Published: October 2020

Resonant Schottky cavity pickups have applications in the measurements of beam parameters in a storage ring. Apart from that they can be used in nondestructive in-ring decay studies of radioactive ion beams. In order to obtain the results of an experiment suitable Data Acquisition System (DAQ) is necessary. Several DAQs were used at Experimental Storage Ring (ESR) at GSI based on the different hardware and software solutions such as TCAP or NTCAP. The goal of this work is to design a prototype of a DAQ using open hardware and open source software defined radio (SDR) and conduct the test measurements at ESR.
Partial cross sections of 181Ta(n,γ) using BEGe detectors
Authors: Heftrich T. , Weigand M. , Brückner B. , El Mard A. , Göbel K. , Khasawneh K. , Kisselbach T. , Kurtulgil D. , Reich M. , Reifarth R. , Sheriff S. , Volknandt M.
Published: October 2020

Heavy nuclei are mainly synthesised by a sequence of neutron captures and β-decays. The corresponding neutron energies in the different astrophysical sites range from 1keV to 1MeV. By using the activation technique, small neutron capture cross sections can be studied. A sample is irradiated by a quasi-stellar neutron spectrum in order to produce radioactive isotopes. The decay of the radioactive nuclei can be detected by their characteristic gamma rays. For this purpose, sensitive experimental detector equipment is needed.

Two Broad Energy Germanium Detectors (BEGe) were recently built up at the Goethe University Frankfurt. The first measurement of the partial neutron capture cross sections for the reaction 181Ta(n,γ) has been performed by using the activation technique.
NICE - Neutron Induced Charged particle Emission
Authors: Al-Khasawneh K. , Borris E. , Bruückner B. , Eberhardt K. , Erbacher P. , Fiebiger S. , Gernhäauser R. , Göobel K. , Heftrich T. , Kisselbach T. , Kurtulgil D. , Langer C. , Reich M. , Reifarth R. , Renisch D. , Thomas B. , Volknandt M. , Weigand M.
Published: October 2020

A new detector setup (NICE-detector) based on an organic plastic scintillator is presented. It will be used during experiments measuring neutron-induced reactions with a charged particle in the exit channel. The proposed design was tested at the Goethe University Frankfurt. One of the test cases was the capture cross-section of 209Bi at different astrophysically important energies, including thermal capture cross-section and resonance integral. This research presents the performance of the detector setup, as well as preliminary results for the calculated cross-sections. The preliminary results demonstrate that the newly developed NICE-detector can be used to determine capture cross-sections with sufficient accuracy, and might be adopted in the future as an alternative for charged particle measurements in different nuclear and astrophysical applications.
19F spectroscopy and implications for astrophysics
Authors: La Cognata M. , Fisichella M. , Di Pietro A. , Figuera P. , Goldberg V. Z. , Cherubini S. , Fernandez Garcia J. P. , Gulino M. , Lamia L. , Lattuada D. , Lattuada M. , Pizzone R.G. , Rapisarda G.G. , Romano S. , Sparta R. , Spitaleri C. , Torresi D. , Tumino A. , Zadro M.
Published: October 2020

The spectroscopy of F is of interest for nuclear astrophysics and nuclear structure. In these proceedings we will focus on the astrophysical implications and on the perspectives of the use of elastic scattering for the investigation of reactions of astrophysical importance. In astrophysics, fluorine and the reactions producing and destroying it play a key role in constraining models of stars in different evolutionary stages, such as the asymptotic giant branch (AGB) stars, responsible of the production of about half of the elements heavier than Fe. Indeed, s-nuclei are produced and brought to the surface thanks to mixing phenomena, together with fluorine that is produced in the same region from the same neutron source. Since the last stage in fluorine nucleosynthesis is the N(α, γ) F radiative capture, the study of the N + α elastic scattering may cast light on the fluorine synthesis. Also, F states are responsible of the appearance of resonances in the O(p,α) N reaction, leading to the production of N, later burnt to F in AGB stars through α-captures. Finally, the F spectroscopy may help constraining nuclear properties of the radioactive mirror nucleus Ne, whose states play a key role in novae modeling through the F(p,α) O reaction. In this work, the N - α elastic scattering is studied using the thick target inverse kinematics approach, allowing us to span a very large fluorine excitation energy range (∼ 6 - 10 MeV). A R-matrix analysis of the measured differential cross sections was also carried out, making it possible to determine the spin-parity and widths of a number of F states, including some previously not reported in the literature.
Astrophysical production of 146Sm in nuclear p - processes
Authors: Oprea Cristiana , Mihul Alexandru , Oprea Alexandru Ioan , Zgura Sorin , Potlog Mihai , Neagu Alina
Published: October 2020

The large time of life of 146Sm suggests the possibility to use this p - nuclide as astrophysical chronometer to study the geochemical galactic evolution. Due to the high temperature and large densities of gamma quanta, neutrons and protons in stellar environment 146Sm nucleus can be obtained in (γ,n), (n,2n), (p,2n) processes on 147Sm.The knowledge of corresponding cross sections of gamma rays, neutrons and alpha induced processes is of a great importance for the explanation of (146Sm/144Sm) ratio uncertainties observed on the Earth, meteorites, Moon and other celestial bodies.Cross sections of (γ,n), (n,2n), (α,γ) processes induced by fast gamma rays, neutrons and alphas on 147Sm and 142Nd, from threshold up to 25 MeV were evaluated and predicted in the frame of Hauser-Feshbach statistical model by using Talys software and the own computer programs. For each nuclear reaction contribution of direct, compound and pre-equilibrium mechanisms were determined. Theoretical evaluations are compared with existing experimental data. Parameters of optical potential in the incident and emergent channels and of nuclear densities were extracted. Calculated cross sections together with corresponding nuclear data were used in the evaluation of astrophysical rates necessary in the determination of elemental abundances as needed by nuclear astrophysical networks.
Indirect study of the 3He(n, p)3H reaction at cosmological energies
Authors: Spampinato C. , Pizzone R.G. , Spart`a R. , Couder M. , Tan W. , Burian V. , Chae K.Y. , D’Agata G. , Guardo G.L. , La Cognata M. , Lamia L. , Lattuada D. , Mrazek J. , Oliva A. , Palmerini S. , Prajapati P. , Rapisarda G.G. , Romano S. , Sergi M.L. , Spitaleri C. , Tumino A. , Wiescher M. , Anguilar S. , Bardayan D.W. , Blankstein D. , Boccioli L. , Callahan L. , Clark A. , Frentz B. , Hall M. , Gula A. , Henderson S. , Kelmar R. , Liu Q. , Long J. , Majumdar A. , McGuinness S. , Nelson A. , O’Malley P.D. , Seymour C. , Skulski M. , Wilkinson J.
Published: October 2020

In the network of reactions present in the Big Bang nucleosynthesis, the 3He(n, p)3H reaction has an important role which impacts the final 7Li abundance. The Trojan Horse Method (THM) has been applied to the 3He(d, pt)H reaction in order to extract the astrophysical S(E)-factor of the 3He(n, p)3H reaction in the Gamow energy range. The experiment will be described in the present work together with the first preliminary results.
Activation cross section measurement of the 100Mo(α,n)103Ru reaction for optical potential studies
Authors: Szegedi T.N. , Kiss G.G. , Gyürky Gy. , Mohr P.
Published: October 2020

The light neutron-rich nuclei can be synthesized via (α,n) reactions in the so-called weak r-process. The abundances of these species are derived using reaction network calculations. Such a simulation has astrophysical and nuclear physics inputs, one of the most uncertain parameter is the α-nucleus optical potential. (α,n) cross section measurements can be used to evaluate α-optical potentials. For this purpose, the activation cross section measurement of the 100Mo(α,n)103Ru reaction is in progress at Atomki.
Activation measurement of a-induced cross sections for 197Au: analysis in the statistical model and beyond
Authors: Szücs T , Mohr P , Gyürky Gy , Halász Z , Huszánk R , Kiss G G , Szegedi T N , Török Zs , Fülöp Zs
Published: October 2020

Cross sections of ( α,γ), (α,n), and (α,2n) reactions for 197Au were measured below the Coulomb barrier using the activation technique. The new data are analyzed in the statistical model and in a simple barrier transmission model. Sensitivities of the resulting cross sections on the underlying parameters are discussed. It is found that the cross sections in the statistical model depend sensitively on the tail of the imaginary α-nucleus potential at large radii outside the colliding nuclei. Contrary, the cross sections in the barrier transmission model depend only on the real part of the α-nucleus potential. The calculated cross sections in the barrier transmission model agree nicely with the new experimental data. Furthermore, the available experimental data for heavy targets above A ≈150 are also well reproduced within the barrier transmission model.
Stellar 78,80,84,86Kr(n,γ) Reactions Studied by Activation at SARAF-LiLiT, Atom Trap Trace Analysis and Decay Counting
Authors: Tessler M. , Paul M. , Weissman L. , Zappala J. , Baggenstos D. , Halfon S. , Heftrich T. , Jiang W. , Kreisel A. , Lu Z. , Mueller P. , Purtschert R. , Reifarth R. , Shor A. , Veltum D. , Weigand M.
Published: October 2020

We report on (n,γ) neutron capture experiments performed with the Liquid-Lithium Target (LiLiT) and the mA-proton beam at 1.92 MeV (2-3 kW) from the Soreq Applied Research Accelerator Facility (SARAF). The setup yields high-intensity 30-keV quasi-Maxwellian neutrons (3-5 × 1010 n/s) closely reproducing the conditions of s-process stellar nucleosynthesis. The 78,80,8486Kr(n,γ) reactions at the border between weak- and strong- s-process were studied. A Ti sphere filled with 107.7 mg of natural Kr gas was placed in an irradiation chamber downstream of LiLiT with a gold foil used as a neutron fluence monitor during the activation. The activities of the short-lived Kr isotopes (7985m87Kr) were measured by γ decay counting with a HPGe detector. The long-lived Kr isotopes (81,85gKr) were measured by atom counting via Atom Trap Trace Analysis (ATTA) at Argonne and Low-Level Counting (LLC) at Bern.
Modeling the formation of the 13C neutron source in AGB stars
Authors: Vescovi D , Cristallo S
Published: October 2020

A major source of uncertainty in AGB models is the partial-mixing process of hydrogen, required for the formation of the so-called 13C pocket. Among the attempts to derive a self-consistent treatment of this physical process, there are 2D and 3D simulations of magnetic buoyancy. The 13C pocket resulting from mixing induced by magnetic buoyancy extends over a region larger than those so far assumed, showing an almost flat 13C distribution and a negligible amount of 14N. Recently, it has been proved to be a good candidate to match the records of isotopic abundance ratios of s-elements in presolar SiC grains. However, up to date such a magnetic mixing has been applied in post-process calculations only, being never implemented in a stellar evolutionary code. Here we present new stellar models, performed with the 1-d hydrostatic FUNS evolutionary code, which include magnetic buoyancy. We comment the resulting s-process distributions and show preliminary comparisons to spectroscopic observations and pre-solar grains measurements.
Spallation of r-Process Nuclei Ejected from a Neutron Star Merger
Authors: Wang Xilu , Fields Brian D. , Mumpower Matthew , Sprouse Trevor , Surman Rebecca , Vassh Nicole
Published: October 2020

Neutron star mergers (NSMs) are rapid neutron capture (r-process) nucleosynthesis sites, which eject materials at high velocities, from 0.1c to as high as 0.6c. Thus the r-process nuclei ejected from a NSM event are sufficiently energetic to initiate spallation reactions with the interstellar medium (ISM) particles. With a thick-target model for the propagation of high-speed heavy nuclei in the ISM, we find that spallation reactions may shift the r-process abundance patterns towards solar data, particularly around the low-mass edges of the r-process peaks where neighboring nuclei have very different abundances. The spallation effects depend both on the astrophysical conditions of the r-process nuclei and nuclear physics inputs for the nucleosynthesis calculations and the propagation process. This work extends that of [Wang et al.(2019)] by focusing on the influence of nuclear physics variations on spallation effects.
Development of electrically conductive porous silk fibroin/carbon nanofiber scaffolds
Authors: Tufan Yiğithan , Öztatlı Hayriye , Garipcan Bora , Ercan Batur
Published: October 2020

Tissue engineering applications typically require three-dimensional scaffolds which provide the requisite surface area for cellular functions, while allowing transport of nutrients, waste and oxygen to and from the surrounding tissues. Scaffolds need to ensure sufficient mechanical properties to provide mechanically stable frameworks under physiologically relevant stress levels. Meanwhile, electrically conductive platforms are also desirable for the regeneration of specific tissues, where electrical impulses are transmitted throughout the tissue for proper physiological functioning. Towards this goal, carbon nanofibers (CNFs) were incorporated into silk fibroin (SF) scaffolds whose pore size and porosity were controlled during a salt leaching process. In our methodology, CNFs were dispersed in SF due to the hydrogen bond-forming ability of hexafluoro-2-propanol, a fluoroalcohol used as a solvent for SF. Results showed enhanced electrical conductivity and mechanical properties upon the incorporation of CNFs into the SF scaffolds, while the metabolic activities of cells cultured on SF/CNF nanocomposite scaffolds were significantly improved by optimizing the CNF content, porosity and pore size range of the scaffolds. Specifically, SF/CNF nanocomposite scaffolds with electrical conductivities as high as 0.023 S cm−1, tangent modulus values of 260 ± 30 kPa, a porosity as high as 78% and a pore size of 376 ± 53 µm were fabricated for the first time in the literature. Furthermore, an increase of about 34% in the wettability of SF was achieved by the incorporation of 10% CNF, which provided enhanced fibroblast spreading on scaffold surfaces.
Electrospun nanofiber scaffolds for the propagation and analysis of breast cancer stem cells in vitro
Authors: Prieto E I , Mojares E B A , Cortez J J M , Vasquez Jr M R
Published: October 2020

Despite advances in cancer treatment, breast cancer remains the second foremost cause of cancer mortality among women, with a high rate of relapse after initial treatment success. A subpopulation of highly malignant cancer cells, known as cancer stem cells (CSCs), is suspected to be linked to metastasis and relapse. Targeting of CSCs may therefore provide a means of addressing cancer-related mortality. However, due to their low population in vivo and a lack of proper culture platform for their propagation, much of the CSC biology remains unknown. Since maintenance of CSCs is heavily influenced by the tumor microenvironment, this study developed a 3D culture platform that mimics the metastatic tumor extracellular matrix (ECM) to effectively increase CSC population in vitro and allow CSC analysis. Through electrospinning, nanofibers that were aligned, porous, and collagen-coated were fabricated from polycaprolactone to recreate the metastatic tumor ECM assemblage. Breast cancer cells seeded onto the nanofiber scaffolds exhibited gross morphology and cytoskeletal phenotype similar to invasive cancer cells. Moreover, the population of breast cancer stem cells increased in nanofiber scaffolds. Analysis of breast cancer cells grown on the nanofiber scaffolds demonstrated an upregulation of mesenchymal markers and an increase in cell invasiveness suggesting the cells have undergone epithelial-mesenchymal transition. These results indicate that the fabricated nanofiber scaffolds effectively mimicked the tumor microenvironment that maintains the cancer stem cell population, offering a platform to enrich and analyze CSCs in vitro.
The role of negative carbon emissions in reaching the Paris climate targets: The impact of target formulation in integrated assessment models
Authors: Johansson Daniel J A , Azar Christian , Lehtveer Mariliis , Peters Glen P
Published: October 2020

Global net-negative carbon emissions are prevalent in almost all emission pathways that meet the Paris temperature targets. In this paper, we generate and compare cost-effective emission pathways that satisfy two different types of climate targets. First, the common approach of a radiative forcing target that has to be met by the year 2100 (RF2100), and, second, a temperature ceiling target that has to be met over the entire period, avoiding any overshoot. Across two integrated assessment models (IAMs), we found that the amount of net-negative emissions—when global net emissions fall below zero—depends to a large extent on how the target is represented, i.e. implemented in the model. With a temperature ceiling (no temperature overshoot), net-negative emissions are limited and primarily a consequence of trade-offs with non-CO2 emissions, whereas net-negative emissions are significant for the RF2100 target (temperature overshoot). The difference becomes more pronounced with more stringent climate targets. This has important implications: more stringent near-term emission reductions are needed when a temperature ceiling is implemented compared to when an RF2100 target is implemented. Further, in one IAM, for our base case assumptions, the cost-effective negative carbon emissions (i.e. gross anthropogenic removals) do not depend to any significant extent on how the constraint is implemented, only, largely, on the ultimate stringency of the constraint. Hence, for a given climate target stringency in 2100, the RF2100 target and the temperature ceiling may result in essentially the same amount of negative carbon emissions. Finally, it is important that IAM demonstrate results for diverse ways of implementing a climate target, since the implementation has implications for the level of near-term emissions and the perceived need for net-negative emissions (beyond 2050).
High temperature wettability and oxidation behavior of TiN, Ti–Al–N and Ti–Si–N PVD film
Authors: Duan Lili , Wu Hua , Xiu Wencui , Yu Xiaofeng , Guo Liming
Published: October 2020

In aluminium cutting and die casting, tools are exposed to Built UP Edge (BUE) and Built Up Layer (BUL) and erosion due to the frequent contact of the tool surface to the aluminum alloy, to oxidation due to high temperatures. For this reason, the susceptibility to reaction with liquid aluminum and stability of TiN, Ti–Al–N and Ti–Si–N films were investigated using wetting test, high temperature oxidation experiment and complementary differential scanning calorimetry. The results show that the type of chemical bond affects the surface tension, tool steel with metal bonds is most easily wetted, after being wetted and cooled by molten Al at 725 °C, the contact angle is approximately 0°. Because the maximum temperature of the experiment has reached the decomposition temperature of TiN film, therefore, the contact angle of TiN film with ionic bond is 35.3°, slightly larger than tool steel. However, there are complex ionic bond compounds Ti3AlN and covalent bond compounds Si3N4 in Ti–Al–N and Ti–Si–N films, which significantly reduce the wettability of the film with molten aluminum. The contact angles are 78° and 71°, respectively. During the oxidation process, due to Ti–Al–N and Ti–Si–N films contain Al and Si elements, the phase and morphology did not change until 800 °C, this indicates that the effects of different chemical bonds caused by alloying elements on oxidation resistance and wetting resistance have a similar relationship.
Improved autonomous error correction using variable dissipation in small logical qubit architectures
Authors: Pérez David Rodríguez , Kapit Eliot
Published: October 2020

Coherence times for superconducting qubits have greatly improved over time. Moreover, small logical qubit architectures using engineered dissipation have shown great promise for further improvements in the coherence of a logical qubit manifold comprised of few physical qubits. Nevertheless, optimal working parameters for small logical qubits are generally not well understood. This work presents several approaches to finding preferential parameter configurations by looking at three different cases of increasing complexity. We begin by looking at state stabilization of a single qubit using dissipation via coupling to a lossy object. We look at the limiting factors in this approach to error correction, and how we address those by numerically optimizing the parametric coupling strength with the lossy object having an effective time-varying dissipation rate—we call this a pulse-reset cycle. We then translate this approach to more efficient state stabilization to an abstracted three-qubit flip code, and end by looking at the very small logical qubit (VSLQ). By using these techniques, we can further increase logical state lifetimes for different architectures. We show significant advantages in using a pulse-reset cycle over numerically optimized, fixed parameter spaces.
4. The writing rabbit
Authors: Restall Matthew , Solari Amara
Published: October 2020

“The writing rabbit” explores the central importance of art in the Maya world. At the highest levels of society, art lent ideological support to ruling lineages. Mayas at various levels of society were proficient in the ceramic and lapidary arts. Scholars have been fascinated by the “Maya code” for generations and we can read now almost all their extant texts. Their hieroglyphic writing was logophonetic, a combination of logographic and phonetic. The Maya made books from beaten fig bark, known as codices, four of which survive. Maya architecture, both domestic and urban, was formed around patios or plazas. Late Classic rulers advertised their political might through large-scale urban projects.
3. Making films in the silent era
Authors: Kornhaber Donna
Published: October 2020

“Making films in the silent era” looks at the business of film production and the attempts of early pioneers to forge new cinematic styles. Women were central to silent film, with some holding positions of power equal to men and running studios before they were able to vote in the United States—a condition that came to a close with the rise of “talkies.” African American filmmakers, Asian American filmmakers, and others connected with audiences by bypassing the Hollywood system. The genres of silent film in some cases appear wholly distinct from later filmmaking trends and in other cases presage such mainstay forms as horror, sci-fi, and the Western, which existed alongside modes of filmmaking like animation and documentary that persisted into later eras.
2. The suburban solution
Authors: Abbott Carl
Published: October 2020

Between the 1940s and 1970s, new lower-density satellite developments were made possible by transport and travel innovations. “The Suburban Solution” describes how suburbs were conceived and marketed as healthy, pleasant alternatives to industrial hubs. Some suburban developments and new towns were successful in easing the overpopulation of nearby cities and providing a quieter life. They have been criticized for their bland appearance, lack of definition, and inefficient use of land. Suburbs, satellites, and garden cities increased families’ reliance on cars, contributing to traffic. New approaches to suburbia aim to address these problems, building in healthy walks and accessible community services.
4. Contested communities
Authors: Abbott Carl
Published: October 2020

City planning allocates the costs and benefits of urban living, and therefore is inherently political. “Contested communities” outlines the development of formal municipal zoning as an alternative to the privatization of desirable land by powerful groups. Zoning quickly became a useful and widely adopted planning tool. It was also a vehicle for racial and economic bias, and some cities are still experiencing its legacy. For many years, city planning neglected women’s safety and travel needs, and women’s contributions to planning were more likely to take place on the ground. What are the alternatives to top-down planning? Can planners replace traditional patterns of gentrification and displacement with urban revitalization?
Conclusion—from soft matter to life
Authors: McLeish Tom
Published: October 2020

The Conclusion looks at the topics that haven't been covered in this VSI. There is so much more to the topic to be learnt: recent developments in rheology at the single molecule level through atomic force microscopy, and the single polymer imaging of confocal microscopy to name but a few. It is an undisputed truth that, through evolution, life itself has recruited the structures of soft matter for its own purposes. Polymers, membranes, liquid crystallinity, self-assembly form its fundamental constituents, from the humblest bacterium to the most complex multicellular creature. The tree of life has taken these materials and combined them in vast complexities of such intricacy that the student of simple systems is easily bewildered by the questions of life.
2. Colonialisms, decolonization, decoloniality
Authors: Young Robert J. C.
Published: October 2020

‘Colonialisms, decolonization, decoloniality’ explains that colonization took two major forms: the first, with colonizers gradually taking over land where sovereignty was not established in a European way, or occupying a foreign state, and then administering and taxing it; the second, with the settlement of Europeans arriving with the intention of adopting the colony as their permanent home. Such ‘settler colonialism’ has had continuing effects on the indigenous peoples right up to the present day. Here, anti-colonial activists argue that decolonization begins with decolonizing oneself from the settler colonial culture. Intellectual decolonization has to form a part of political decolonization.
4. History and power, from below and above
Authors: Young Robert J. C.
Published: October 2020

‘History and power, from below and above’ addresses the continuing interference by former colonial powers in the internal affairs of independent decolonized states. Indeed, countries that achieved sovereignty in their independence struggles still find that they are the object of interventions by the Western countries that had once ruled them. Has the Middle East ever really been free of Western interference since Napoleon invaded Egypt in 1798 or the remnants of the Ottoman Empire were divided up between Britain and France at the end of the First World War? An interesting example can be seen in the intermittent bombing of Baghdad and Iraq by Western powers since 1920.
8. Gender, queering, and feminism in a postcolonial context
Authors: Young Robert J. C.
Published: October 2020

‘Gender, queering, and feminism in a postcolonial context’ explains how recently, ‘queer’ and ‘queering’ have been adopted to describe a strategy of shifting social or intellectual perspectives out of their dominant binary forms. It is often in societies of the Global South that patriarchal norms remain strongest. It is also where the greatest resistance can be found to more flexible ideas of genders and sexualities, which are sometimes portrayed as yet another instance of Western cultural imperialism. Queering the norms of such cultures—in Africa, the Middle East, or the Caribbean, for example—has become a major, sometimes controversial, arena of postcolonial gender politics.
9. Globalization from a postcolonial perspective
Authors: Young Robert J. C.
Published: October 2020

'Globalization from a postcolonial perspective' begins by considering how Che Guevara was influenced by Frantz Fanon’s The Wretched of the Earth, which rapidly became the bible of decolonization after its publication in 1961. However, the inexorable forces of globalization since the 1980s have increasingly brought the world’s economies into a single capitalist system. While multi- and transnational companies looked to global markets for growth, they simultaneously lowered their cost base by outsourcing manufacturing or administration to any country that was poor and reasonably politically stable; few societies today have not felt the impact of their place in the world economy and the international division of labour.
1. Citizen soldier and sailor vs. standing armed forces
Authors: Glatthaar Joseph T.
Published: October 2020

“Citizen soldier and sailor vs. standing armed forces” covers the establishment of the first militias in the colonies. Colonists inherited a British sense of military obligation but were opposed to standing armies. British wars drew in American forces, fostering Anglo-American discord. Stylized European warfare did not translate to the American landscape. Indigenous groups required, and indirectly taught, newer tactics. Americans under George Washington achieved independence through strategic alliances and contributions from the Continental Army, the militia, and partisans. The Navy also developed during the Revolutionary War. After the war, Republicans and Federalists disagreed on the best approach to the military.
2. The struggle for military professionalism
Authors: Glatthaar Joseph T.
Published: October 2020

“The struggle for military professionalism” looks at the positive effect of the West Point Academy on American military expertise and the improved sense of professionalism among its graduating classes. During the American Civil War, non-graduates could make more progress in the military. The Union Army’s victory stemmed from their ability to convert their superior manpower and technology into military power. After the war, the Army and Navy suffered crises of mission. A curriculum was founded for the Navy, but at the end of the nineteenth century the Army and Navy were still not professionalized. The Navy lacked structure, and the Army had structure but suffered from an outdated military culture.
3. Technology, mechanization, and the world wars
Authors: Glatthaar Joseph T.
Published: October 2020

Technology alone does not transform warfare. “Technology, mechanization and the world wars” demonstrates that it needs to be paired with organization and sound doctrine. The two world wars saw advances in military aviation and naval warfare. During World War II, resources were divided between two theaters: the European and the Pacific. American society was transformed, with a booming economy and more opportunities in defense and the military. Not everyone benefited; hundreds of thousands of Japanese Americans were interned. Conventional bombings and blockades diminished in effectiveness throughout World War II, which ended with the unprecedented decision to drop atomic bombs on Japan.
ECMarker: interpretable machine learning model identifies gene expression biomarkers predicting clinical outcomes and reveals molecular mechanisms of human disease in early stages
Authors: Jin Ting , Nguyen Nam D , Talos Flaminia , Wang Daifeng
Published: October 2020

Motivation

Gene expression and regulation, a key molecular mechanism driving human disease development, remains elusive, especially at early stages. Integrating the increasing amount of population-level genomic data and understanding gene regulatory mechanisms in disease development are still challenging. Machine learning has emerged to solve this, but many machine learning methods were typically limited to building an accurate prediction model as a ‘black box’, barely providing biological and clinical interpretability from the box.

Results

To address these challenges, we developed an interpretable and scalable machine learning model, ECMarker, to predict gene expression biomarkers for disease phenotypes and simultaneously reveal underlying regulatory mechanisms. Particularly, ECMarker is built on the integration of semi- and discriminative-restricted Boltzmann machines, a neural network model for classification allowing lateral connections at the input gene layer. This interpretable model is scalable without needing any prior feature selection and enables directly modeling and prioritizing genes and revealing potential gene networks (from lateral connections) for the phenotypes. With application to the gene expression data of non-small-cell lung cancer patients, we found that ECMarker not only achieved a relatively high accuracy for predicting cancer stages but also identified the biomarker genes and gene networks implying the regulatory mechanisms in the lung cancer development. In addition, ECMarker demonstrates clinical interpretability as its prioritized biomarker genes can predict survival rates of early lung cancer patients (P-value < 0.005). Finally, we identified a number of drugs currently in clinical use for late stages or other cancers with effects on these early lung cancer biomarkers, suggesting potential novel candidates on early cancer medicine.

Availabilityand implementation

ECMarker is open source as a general-purpose tool at https://github.com/daifengwanglab/ECMarker.

Supplementary information

Supplementary data are available at Bioinformatics online.
Elicitation complexity of statistical properties
Authors: Frongillo Rafael M , Kash Ian A
Published: October 2020

A property, or statistical functional, is said to be elicitable if it minimizes the expected loss for some loss function. The study of which properties are elicitable sheds light on the capabilities and limitations of point estimation and empirical risk minimization. While recent work has sought to identify which properties are elicitable, here we investigate a more nuanced question: how many dimensions are required to indirectly elicit a given property? This number is called the elicitation complexity of the property. We lay the foundation for a general theory of elicitation complexity, which includes several basic results on how elicitation complexity behaves and the complexity of standard properties of interest. Building on this foundation, our main result gives tight complexity bounds for the broad class of Bayes risks. We apply these results to several properties of interest, including variance, entropy, norms and several classes of financial risk measures. The article concludes with a discussion and open questions.