bluuebunny/crossref_metadata_2025_split huggingface dataset:
A qualitative classification of extraterrestrial civilizations
Authors: Ivanov Valentin D. , Beamín Juan Carlos , Cáceres Claudio , Minniti Dante 
Published: June 2020

Context.Interest in searches for extraterrestrial civilizations (ETCs) has been boosted in recent decades by the discovery of thousands of exoplanets.Aims.We turn to the classification of ETCs for new considerations that may help to design better strategies for searching for ETCs.Methods.This study is based on analogies with our own biological, historical, technological, and scientific development. We took a basic taxonomic approach to ETCs and investigated the implications of the new classification on ETC evolution and observational patterns. Finally, we used the quantitative scheme of Kardashev and considered its implications on the searches for ETCs as a counter example to our qualitative classification.Results.We propose a classification based on the abilities of ETCs to modify and integrate with their environments: Class 0 uses the environment as it is, Class 1 modifies the environment to fit its needs, Class 2 modifies itself to fit the environment, and a Class 3 ETC is fully integrated with the environment. Combined with the classical Kardashev scale, our scheme forms a two-dimensional method for interpreting ETC properties.Conclusions.The new framework makes it obvious that the available energy is not a unique measure of ETC progress: it may not even correlate with how well that energy is used. The possibility for progress without increased energy consumption implies a lower detectability, so in principle the existence of a Kardashev Type III ETC in the Milky Way cannot be ruled out. This reasoning weakens the Fermi paradox, allowing for the existence of advanced, yet not energy hungry, low-detectability ETCs. The integration of ETCs with the environment will make it impossible to tell technosignatures and natural phenomena apart. Therefore, the most likely opportunity for SETI searches to find advanced ETCs is to look for beacons, specifically set up by them for young civilizations like ours (if they would want to do that remains a matter of speculation). The other SETI window of opportunity is to search for ETCs at technological level similar to ours. To rephrase the famous saying of Arthur Clarke, sufficiently advanced civilizations are indistinguishable from nature.
An optical spectroscopic and polarimetric study of the microquasar binary system SS 433
Authors: Picchi Paolo , Shore Steven N. , Harvey Eamonn J. , Berdyugin Andrei 
Published: June 2020

Aims. Our aim is to study the mass transfer, accretion environment, and wind outflows in the SS 433 system, concentrating on the so-called stationary lines.
Methods. We used archival high-resolution (X-shooter) and low-resolution (EMMI) optical spectra, new optical multi-filter polarimetry, and low-resolution optical spectra (Liverpool Telescope), spanning an interval of a decade and a broad range of precessional and orbital phases, to derive the dynamical properties of the system.
Results. Using optical interstellar absorption lines and H I 21 cm profiles, we derive E(B − V) = 0.86 ± 0.10, with an upper limit of E(B − V) = 1.8 ± 0.1 based on optical Diffuse Interstellar Bands. We obtain revised values for the ultraviolet and U band polarizations and polarization angles (PA), based on a new calibrator star at nearly the same distance as SS 433 that corrects the published measurement and yields the same PA as the optical. The polarization wavelength dependence is consistent with optical-dominating electron scattering with a Rayleigh component in U and the UV filters. No significant phase modulation was found for PA while there is significant variability in the polarization level. We fortuitously caught a flare event; no polarization changes were observed but we confirm the previously reported associated emission line variations. Studying profile modulation of multiple lines of H I, He I, O I, Na I, Si II, Ca II, Fe II with precessional and orbital phase, we derive properties for the accretion disk and present evidence for a strong disk wind, extending published results. Using transition-dependent systemic velocities, we probe the velocity gradient of the wind, and demonstrate that it is also variable on timescales unrelated to the orbit. Using the rotational velocity, around 140 ± 20 km s−1, a redetermined mass ratio q = 0.37 ± 0.04, and masses MX = 4.2 ± 0.4 M⊙, MA = 11.3 ± 0.6 M⊙, the radius of the A star fills – or slightly overfills – its Roche surface. We devote particular attention to the O I 7772 Å and 8446 Å lines, finding that they show different but related orbital and precessional modulation and there is no evidence for a circumbinary component. The spectral line profile variability can, in general, be understood with an ionization stratified outflow predicted by thermal wind modeling, modulated by different lines of sight through the disk produced by its precession. The wind can also account for an extended equatorial structure detected at long wavelength.
Glomus tumors of the nail bed: topographic anatomy and an algorithmic approach based on the topography
Authors: Civan Osman , Güntürk Özgün Barış , Özaksar Kemal , Cavit Ali , Özcanli Haluk 
Published: June 2020

Abstract
Purpose Glomus tumors are rare vascular pathologies characterized by a triad of symptoms: tenderness, pain and cold intolerance. In the hand they are highly concentrated under the nail bed. In this retrospective study, we aimed to present a topographic map of the location of glomus tumors in the nail bed and a map-based surgical approach algorithm to the subungual glomus tumors.
Methods We prepared a nail bed map with 6 zones and named these zones as ulnar distal, ulnar proximal, central distal, central proximal, radial distal and radial proximal. With respect to the tumor location and the used surgical approach we retrospectively evaluated the intraoperative photos and the hospital records of patients who were operated between 2008–2019 and had the pathological diagnosis of glomus tumor. The examination records of the postoperative first year were evaluated for each patient retrospectively. A descriptive statistical analysis was performed. In addition we analyzed the described surgical approaches to excise a glomus tumor in the nail bed. The described approaches and the approaches used by us were matched with the localisation of the tumors in this study developing an algorithm for the surgical approach depending on the localisation of the nail bed glomus tumor.
Results Finally 44 patients had inclusion criteria. The distribution of the glomus tumor was as follows: 2 were on ulnar distal (4.5 %), 9 on ulnar proximal (20.5 %), 1 on central distal (2.3 %), 18 on central proximal (40.9 %), 4 on radial distal (9.1 %) and 10 were on the radial proximal zones (22.7 %). 4 lateral approaches, 1 nail sparing and 39 transungual approaches were performed. We had one recurrence in a male patient operated by transungual approach.
Conclusion Glomus tumors are mostly located on the central proximal part of the nail bed. Our glomus map and the algorithm we described might be helpful for the selection of the surgical approach for the glomus tumor.
Sekundäre Beugesehnenplastiken – Wie gut sind sie?
Authors: Moeller Richard-Tobias , Mentzel Martin , Vergote Daniel , Jermendy Philipp Tibor , Bauknecht Simon 
Published: June 2020

Zusammenfassung
Hintergrund Sekundäre Beugesehnenrekonstruktionen sind durch die Erfolge der primären Beugesehnennähte in der heutigen Zeit selten indiziert und einem speziellen Patientenkollektiv vorbehalten. Die Ergebnisse sekundärer Beugesehnenplastiken einer überregionalen, spezialisierten handchirurgischen Einrichtung werden präsentiert und im historischen wie aktuellen Kontext betrachtet.
Patienten und Methoden In einem Zeitraum von 11 Jahren wurden bei insgesamt 644 Beugesehnenversorgungen 52 sekundäre Beugesehnenplastiken durchgeführt: 7 einzeitige Beugesehnentransplantationen, 16 Beugesehnentranspositionen und 29 zweizeitige Beugesehnentransplantationen. Insgesamt konnten von 39 Patienten die Behandlungsergebnisse nach dem Buck-Gramcko-Schema retrospektiv ausgewertet werden.
Ergebnisse In 60 % der einzeitigen Beugesehnentransplantationen konnten sehr gute bis gute Ergebnisse erzielt werden. Funktionelle, d. h. sehr gute bis gute Ergebnisse fanden sich in 75 % der Beugesehnentranspositionen. Bei den zweizeitigen Transplantationen konnte in 50 % der Fälle ein funktionelles Ergebnis festgestellt werden. In der Summe konnten nach sekundären Beugesehnenrekonstruktionen in 58,5 % funktionelle Ergebnisse nach dem Bewertungsschema nach Buck-Gramcko erzielt werden.
Schlussfolgerungen Sekundäre Beugesehnenplastiken haben einen Anteil von 7,5 % am Gesamtgut der verletzen Beugesehnen. Die funktionellen Ergebnisse der sekundären Beugesehnenplastiken sind über Jahrzehnte nahezu unverändert und scheinen sich nicht relevant verbessern zu lassen. Im Vergleich zu einer primären Beugesehnennaht sind die Ergebnisse weiterhin unbefriedigend. Ziel sollte es sein, die primäre Versorgung der Beugesehnen weiter zu optimieren und somit die Notwendigkeit einer sekundären Beugesehnenplastik zu reduzieren.
Diagnosing Muscular Dystrophies: Comparison of Techniques and Their Cost Effectiveness: A Multi-institutional Study
Authors: Srivastava Pallavi , Malhotra Kiran Preet , Husain Nuzhat , Malhotra Hardeep Singh , Kulshreshtha Dinkar , Anand Akanksha 
Published: June 2020

Abstract

Background The diagnosis of muscular dystrophies involves clinical discretion substantiated by dystrophic changes on muscle biopsy. The different subtypes of muscular dystrophy can be diagnosed using techniques to identify the loss of protein or molecular alterations.

Materials and Methods Clinically suspicious cases confirmed to have muscular dystrophy on muscle biopsy seen at two tertiary care centers in North India were enrolled for the study. Immunohistochemistry (IHC) for dystrophin, merosin, sarcoglycan, emerin, and dysferlin proteins was performed. The spectrum of muscular dystrophies diagnosed was analyzed. Cost of diagnosing the cases using IHC was estimated and compared with that of standard molecular tests available for the diagnosis of muscular dystrophies.

Statistics Descriptive statistics were used for data analysis. Mean and standard deviations were used for continuous variables, whereas categorical variables were analyzed using frequency percentage.

Results A total of 47 cases of muscular dystrophies were studied. This included nine cases of Duchenne, three cases of Becker’s dystrophy, and one dystrophinopathy carrier. One case of α, seven cases of β, and two cases of δ sarcoglycanopathy, along with two cases of facioscapulohumeral dystrophy and a single case of dysferlinopathy were detected. Genetic studies were required for a subset of 16 cases. The cost of using muscle biopsy and IHC was substantially lower than that of molecular methods for the identification of muscular dystrophy subtypes.

Conclusion We detailed an algorithmic approach for diagnosing muscular dystrophies using muscle biopsy. The prevalence of biopsy proven muscular dystrophies from two tertiary care centers in North India is compared with that from other centers. Genetic studies are currently of limited availability in India and are more expensive as compared with biopsy and IHC. Using these methodologies sequentially with a “biopsy first approach” may be the prudent approach for low-income countries.
Foreign investor reactions to risk and uncertainty in antitrust: U.S. merger policy investigations and the deterrence of foreign acquirer presence
Authors: Clougherty Joseph A. , Zhang Nan 
Published: June 2020

AbstractMotivated by the potential for antitrust and competition policies to be protectionist in effect, we formulate the theoretical prior that merger policy deters foreign acquirer participation in local M&A markets. The policy risk and policy uncertainty characteristic of merger review may negatively affect foreign acquirers more so than domestic acquirers, thereby disadvantaging foreign acquisitions of local firms and deterring future cross-border investment activities. We test this prior by employing sector-level data on U.S. merger policy investigations and foreign acquirer presence in U.S. M&A markets over the 2002–2017 period. Our panel-data methodological approach indicates that the risk and uncertainty characteristic of U.S. merger policy disproportionately deters the acquisition activities of foreign investors. The empirical results also suggest that the application of competition and merger policies in other national jurisdictions – where there is less of a strong commitment to antitrust principles – might also be effectively protectionist.
“Le Grand absent Européen”: solidarity in the politics of European integration
Authors: Grimmel Andreas 
Published: June 2020

AbstractThe appeal for more solidarity is a recurring pattern in political discussions of how to cope with the crises the European Union (EU) confronts. This became most palpable in two major challenges—the Eurozone crisis and the refugee and migrant crisis. However, there is a yawning gap between the rhetorical commitment to solidarity and member states’ practices of solidarity: Even though the EU and its members regularly refer to solidarity as one of their fundamental values, the concept regularly fails to translate into concrete and common action. This lack of solidarity when it comes to problem resolution not only renders solidarity a weak principle within the EU’s political framework; it also precludes more effective crisis management. Drawing on the works of Ludwig Wittgenstein as well as (neo)pragmatism, this paper argues that a language- and practice-based reading can offer a new perspective on solidarity as one of the EU’s fundamental values. It can also explain why solidarity does not play a more vital role in the EU today, especially in times of crisis, when it is most needed.
Hyperbolic cosine function in physics
Authors: Bonnet Isabelle , Gabelli Julien 
Published: June 2020

Abstract
A catenary is the shape that an electric cable takes under its own weight if suspended only at its ends between two pylons. A rope hung between two masts is also described with a catenary equation which is based on the hyperbolic cosine function. We propose here to approach the hyperbolic cosine function with two simple experiments using a beaded chain. We first study the static form of a chain whose ends are suspended between two poles, when the distance between the two poles varies. Then, we study the dynamics of the same chain falling from the edge of a table. The simplicity of these two experiments, which can be done at home, makes them appropriate for undergraduate students interested in practicals.
Stratified equatorial flows in cylindrical coordinates
Authors: Henry D , Martin C I 
Published: June 2020

Abstract
We construct an exact solution modelling the geophysical dynamics of an inviscid and incompressible fluid which possesses a variable density stratification, where the fluid density may vary with both the depth and latitude. Our solution pertains to the large-scale equatorial dynamics of a fluid body with a free surface propagating steadily in a purely azimuthal direction, and is expressed in terms of cylindrical coordinates. Allowing for general fluid stratification greatly complicates the Bernoulli relation—which relates the imposed pressure to the reciprocal fluid distortion at the free-surface—thereby acting as a constraint on the existence of a solution. Employing the implicit function theorem, we establish the existence of solutions and determine that the requisite monotonicity properties hold for the flow solutions we found. Furthermore, since the fluid velocity and pressure are prescribed by explicit formulae in the framework of cylindrical coordinates, our solution is amenable to analysis by the short-wavelength stability approach, which we investigate.
Polarization phenomena in bichromatic ionization of Ne and Ar induced by circularly polarized VUV femtosecond pulses
Authors: Grum-Grzhimailo A N , Gryzlova E V , Popova M M 
Published: June 2020

Synopsis
Interference effects resulting from direct single-photon and resonant two-photon ionization of neon and argon by bichromatic circularly polarized radiation were investigated in the framework of the perturbation theory. Analytical formulas are obtained for the differential cross section of the process in multielectron noble gas atoms. The possibility of coherent control of the photoelectron angular distribution and spin polarization will be discussed.
Measurements of spatial correlations in quantum gases using ultralong-range strontium Rydberg molecules
Authors: Whalen J D , Ding R , Kanungo S K , Dunning F B , Killian T C , Yoshida S , Burgdörfer J 
Published: June 2020

Synopsis
The photoexcitation of ultralong-range Rydberg molecules is demonstrated as a probe of spatial cor-relations in a quantum gas on previously inaccessible length scales of 1400-3200 a
0. Measurements using cold (∼1 μK) (fermionic) 87Sr and (bosonic) 84Sr reveal the effects of quantum statistics on the pair correlation function g
(2)(R).
Optical shielding for ultracold 39K-Cs binary collisions
Authors: Xie T , Orbán A , Dulieu O , Bouloufa-Maafa N 
Published: June 2020

Synopsis
The optical shielding efficiency in ultracold collisions is investigated for the first time with atoms of different species (39K-Cs) with a close-coupling approach. The spontaneous emission is taken into account through a complex optical potential. The results show that an efficient shielding can be achieved in the presence of a blue-detuned laser. The role of the light polarization on the shielding efficiency is carefully investigated.
Non-adiabatic quantum dynamics of the ultracold Li+LiNa→ Li2+Na chemical reaction
Authors: Kendrick B K , Li M , Li H , Kotochigova S , Croft J F E , Balakrishnan N 
Published: June 2020

Synopsis
We report non-adiabatic dynamics of the Li+LiNa→Li2+Na chemical reaction at cold and ultracold temperatures employing accurate ab initio electronic potential energy surfaces in a quantum dynamics formulation employing a diabatic representation. Results are compared against those from a single adiabatic ground state potential energy surface and a universal model based on the long-range interaction potential. We discuss signatures of non-universal behavior in the total rate coefficients as well as strong non-adiabatic effects in the state-to-state rotationally resolved rate coefficients.
Coincident detection of recoil ions and photoelectrons after multiphoton-ionisation of cold 6Li atoms trapped in a dipole trap
Authors: Kurz N , Mootheril D T M , Mezinska S , Pfeifer T , Dorn A 
Published: June 2020

Synopsis
We report on performing high resolution recoil ion momentum spectroscopy in a reaction microscope (ReMi) on a target of dipole-force trapped cold 6Li atoms in a non-interacting |1〉-|2〉 spin mixture and coincident detection of recoil ions and photoelectrons. Photo-ionization occurs from the electronic ground state of the 6Li atoms and IR photons significantly contribute to the ion yield via 3-photon resonances. High resolution time-of-flight spectra are obtained by modulating the trap depth synced with the arrival of the fs laser pulses.
Low-energy scattering properties of ground-state and excited-state positronium collisions
Authors: Higgins M D , Daily K M , Greene C H 
Published: June 2020

Synopsis
Low-energy elastic and inelastic scattering in the Ps(1s)-Ps(2s) channel is treated in a four-body hyperspherical coordinate calculation. Adiabatic potentials are calculated for triplet-triplet, singlet-singlet, and singlet-triplet spin symmetries of coupled electrons and coupled positrons, with total angular momentum L = 0 and positive parity. Preliminary estimates of the s-wave scattering length in the elastic Ps(1s)-Ps(2s) channel were obtained. Spin recoupling is implemented to obtain calculations of experimentally relevant scattering properties for different Ps spin states.
Tunnelling of the Bose-Einstein condensates in a tilted shallow trap
Authors: Jian Y , Xue J K 
Published: June 2020

Synopsis
Using variational method and numerical simulation, the tunnelling of Bose-Einstein condensates (BECs) in a tilted shallow trap is studied. The stable bound state, the quasi-bound state and the diffusion state are predicted. For a driven shallow trap, the resonance tunnelling phenomenon is observed.
Understanding the formation of metastable furan dication in collisions with ions
Authors: Erdmann E , Indrajith S , Chiarinelli J , Díaz-Tendero S , Aguirre N F , Alcamí M , Domaracka A , Rousseau P , Huber B A , Bolognesi P , Avaldi L , Łabuda M 
Published: June 2020

Synopsis
This work relies on complementary theoretical and experimental studies of the processes induced by ion-furan collisions. Results of the Molecular Dynamics simulations and exploration of the energy profiles combined with coincidence mass spectrometry provide complete picture of the fragmentation of furan dication.
A resonant ionization spectroscopy scheme for photodetachment studies
Authors: Welander J , Navarrete J E Navarro , Kodambattil M , Sundberg J , Lu D , Hanstorp D 
Published: June 2020

Synopsis
A refined Resonant Ionization Spectroscopy (RIS) scheme for high resolution Laser Photodetachment Threshold Spectroscopy (LPTS). In this work the scheme is used to measure the electron affinity of cesium.
Model potential parameters for alkali metal atomic lithium
Authors: Zhao S F , Tang Z F , Jiao Z H , Li W , Wang G L , Zhou X X 
Published: June 2020

Synopsis
The model potential proposed by Laughlin (Phys.Rev.A 64,013406 (2001)) can give accurate bound-state energies of atoms, which is very useful in atomic physics. We determine model potential parameters for alkali metal atomic lithium (Li) by comparing the present calculated bound-state energies with both the experimental singlet energy values and quantum defect calculations.
Electron-impact excitation of the (4p55s5p)4S3/2 quasimetastable state in Rb
Authors: Roman V , Demes S 
Published: June 2020

Synopsis
The ejected-electron excitation function of the (4p55s5p)4S3/2 quasimetastable state in rubidium was experimentally investigated by electron-impact in the energy range from the excitation threshold at 16.64 eV to 100 eV. The obtained data at 0.12 eV energy resolution indicate the presence of negative-ion resonances just above excitation threshold. A comparison is made with the optical excitation function of the (4p55s5p)4S3/2 → (4p65p)2P3/2 transition (λ = 82.37 nm), measured earlier with a lower energy resolution of ≈ 1.5 eV.
Infrared laser spectroscopy measurement of the electron affinity of thallium
Authors: Walter C W , Gibson N D , Patel K R , Spielman S E 
Published: June 2020

Synopsis
The electron affinity of thallium, Tl, has been measured using tunable infrared laser photodetachment threshold spectroscopy. The relative cross section for neutral atom production following photodetachment from Tl− was measured with a crossed laser-ion beam apparatus over the photon energy range 300 - 900 meV. A single s-wave threshold was observed near 320 meV due to the opening of the ground state phodetachment channel, yielding a preliminary value for the electron affinity of thallium. The present results are compared to previous experimental and theoretical results.
Coexistence of cubic and tetragonal phase with colored excitonic emissions in mixed halide Perovskite CH3NH3PbI3-xClx thin film
Authors: Tanveer Karim A M M , Hossain M S , Khan M K R 
Published: June 2020

Synopsis
CH3NH3PbI3-xClx crystalline film composed of cuboids and polyhedral structure was prepared by dipping and withdrawing method at ambient. X-ray diffraction shows the presence of tetragonal and cubic phases having high absorption coefficient of 106 m-1. Photoluminescence study confirms shallow and deep level emissions. Temperature dependent-cathodoluminescence shows a green luminescence at 2.51 eV accompanied by weak red and ultraviolet luminescence at 80 and 300 K.