Unconventional Magnetization below 25 K in Nitrogen-doped Diamond provides hints for the existence of Superconductivity and Superparamagnetism

The magnetization of nitrogen-doped single crystalline diamond bulk samples shows unconventional field and temperature hysteresis loops at T ≲ 25 K. The results suggest the existence of superparamagnetic and superconducting regions in samples with nitrogen concentration <200 ppm. Both phases vanish at temperatures above 25 K where the samples show diamagnetic behavior similar to undoped diamond. The observation of superparamagnetism and superconductivity is attributed to the nitrogen doping and to the existence of defective regions. From particle-induced X-ray emission with ppm resolution we rule out that the main observations below 25 K are due to magnetic impurities. We investigated also the magnetic properties of ferromagnetic/high-temperature superconducting oxide bilayers. The magnetization results obtained from those bilayers show remarkable similarities to the ones in nitrogen-doped diamond

SYSTEMIC, PHASED APPROACH TO THE APPLICATION OF EDUCATIONAL INFLUENCES ON STUDENTS IN STUDYING BIOLOGY

Здійснено теоретичний аналіз психолого-педагогічної та методичної літератури, які розкривають застосування виховних впливів на учнів у процесі вивчення біології. Розкрито системне, поетапне, практичне застосування виховних впливів на уроках біології, спрямованих на активізацію пізнавальної діяльності учнів, що забезпечить підвищення інтересу до навколишнього середовища і цим самим бажання отримати глибші знання і сформувати певні переконання природоохоронної спрямованості. Адже одним із пріоритетів педагогічної діяльності вчителя є формування стійких переконань в учнів, зокрема: формування моральних, етичних, естетичних переконань; бажання до емпатії, нетерпимості до проявів вандалізму стосовно навколишнього середовища. Розглянуто доцільність поетапного застосування виховних впливів на учнів на різних етапах організації процесу вивчення біології, наведено методику поетапного формування морально-етичних норм, естетичних і екологічних переконань. Також проведено експериментальну перевірку ефективності послідовного, системного поетапного застосування виховного впливу на учнів у процесі вивчення біології у напрямі формування позитивного ставлення до природи та пізнавальної, творчої діяльності у соціальній та природоохоронній сферах.Осуществлен теоретический анализ психолого-педагогической и методической литературы, раскрывающих применение воспитательных влияний на учащихся в процессе изучения биологии. А также раскрыто системное, поэтапное, практическое применение воспитательных влияний на уроках биологии, направленных на активизацию познавательной деятельности учащихся, что обеспечит повышение интереса к окружающей среде и тем самым желание получить более глубокие знания и сформировать определенные убеждения природоохранной направленности. Ведь одним из приоритетов педагогической деятельности учителя является формирование устойчивых убеждений учащихся, в частности, формирование нравственных, этических, эстетических убеждений, желание к эмпатии, нетерпимости к проявлениям вандализма по отношению к окружающей среде. Рассмотрена целесообразность поэтапного использования воспитательных воздействий на учащихся на разных этапах организации процесса изучения биологии, приведена методика поэтапного формирования морально-этических норм, эстетических и экологических воспитательных воздействий. Также проведена экспериментальная проверка эффективности последовательного и системного применения воспитательного влияния на учащихся в процессе изучения биологии в направлении формирования положительного отношения к природе и познавательной, творческой деятельности в социальной и природоохранной сферах.The authors present theoretical analysis of psychological, pedagogical, and methodical literature, which reveals the application of educational influences for the students in the studying biology. We consider the formation of persistent beliefs of students to be one of the priorities in teacher's pedagogical activity, in particular, the formation of moral, ethical, aesthetic beliefs, a desire for empathy, and intolerance to manifestations of vandalism to the environment. In this context, studies of the right perception of adolescents become important in the cognitive activity. We determined the tasks for the realization of this goal to be as follows: the development of an educational influences system at the biology lessons in the direction of the educational and work skills formation; a combination of lesson and extra-curricular activities to consolidate and deepen beliefs. Accordingly, education was carried out as a systematic, phased, practical application of educational influences during the biology lessons, aimed at enhancing students' cognitive activity, which would increase the interest in the environment, and thus the desire to obtain more depth knowledge and form certain beliefs in the nature protection orientation. The expediency of the phased implementation of educational influences on students at different stages of the organization of the process during studying biology is considered, the method of phased formation of moral and ethical norms, aesthetic and environmental educational impacts is presented. In addition, an experimental verification of the effectiveness for the systematic, phased implementation of educational influences on students during the studying of biology in the direction of forming a positive attitude towards nature and cognitive, creative activity in the social and environmental sphere was carried out. The results allowed to develop a system of conditions aimed at increasing the effect of educational influences on students during the study of biology

A formally verified abstract account of Gödel's incompleteness theorems

We present an abstract development of Gödel’s incompleteness theorems, performed with the help of the Isabelle/HOL theorem prover. We analyze sufficient conditions for the theorems’ applicability to a partially specified logic. In addition to the usual benefits of generality, our abstract perspective enables a comparison between alternative approaches from the literature. These include Rosser’s variation of the first theorem, Jeroslow’s variation of the second theorem, and the S ́wierczkowski–Paulson semantics-based approach. As part of our framework’s validation, we upgrade Paulson’s Isabelle proof to produce a mech- anization of the second theorem that does not assume soundness in the standard model, and in fact does not rely on any notion of model or semantic interpretation

Search for Eccentric Black Hole Coalescences during the Third Observing Run of LIGO and Virgo

Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass $M>70$ $M_\odot$) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities $0 < e \leq 0.3$ at $0.33$ Gpc$^{-3}$ yr$^{-1}$ at 90\% confidence level.Comment: 24 pages, 5 figure

Search for subsolar-mass black hole binaries in the second part of Advanced LIGO’s and Advanced Virgo’s third observing run

We describe a search for gravitational waves from compact binaries with at least one component with mass 0.2 M⊙–1.0 M⊙ and mass ratio q ≥ 0.1 in Advanced LIGO and Advanced Virgo data collected between 1 November 2019, 15:00 UTC and 27 March 2020, 17:00 UTC. No signals were detected. The most significant candidate has a false alarm rate of 0.2yr−1 ⁠. We estimate the sensitivity of our search over the entirety of Advanced LIGO’s and Advanced Virgo’s third observing run, and present the most stringent limits to date on the merger rate of binary black holes with at least one subsolar-mass component. We use the upper limits to constrain two fiducial scenarios that could produce subsolar-mass black holes: primordial black holes (PBH) and a model of dissipative dark matter. The PBH model uses recent prescriptions for the merger rate of PBH binaries that include a rate suppression factor to effectively account for PBH early binary disruptions. If the PBHs are monochromatically distributed, we can exclude a dark matter fraction in PBHs fPBH ≳ 0.6 (at 90% confidence) in the probed subsolar-mass range. However, if we allow for broad PBH mass distributions we are unable to rule out fPBH = 1. For the dissipative model, where the dark matter has chemistry that allows a small fraction to cool and collapse into black holes, we find an upper bound fDBH &lt; 10−5 on the fraction of atomic dark matter collapsed into black holes

Model-based cross-correlation search for gravitational waves from the low-mass X-ray binary Scorpius X-1 in LIGO O3 data

We present the results of a model-based search for continuous gravitational waves from the low-mass X-ray binary Scorpius X-1 using LIGO detector data from the third observing run of Advanced LIGO, Advanced Virgo and KAGRA. This is a semicoherent search which uses details of the signal model to coherently combine data separated by less than a specified coherence time, which can be adjusted to balance sensitivity with computing cost. The search covered a range of gravitational-wave frequencies from 25Hz to 1600Hz, as well as ranges in orbital speed, frequency and phase determined from observational constraints. No significant detection candidates were found, and upper limits were set as a function of frequency. The most stringent limits, between 100Hz and 200Hz, correspond to an amplitude h0 of about 1e-25 when marginalized isotropically over the unknown inclination angle of the neutron star's rotation axis, or less than 4e-26 assuming the optimal orientation. The sensitivity of this search is now probing amplitudes predicted by models of torque balance equilibrium. For the usual conservative model assuming accretion at the surface of the neutron star, our isotropically-marginalized upper limits are close to the predicted amplitude from about 70Hz to 100Hz; the limits assuming the neutron star spin is aligned with the most likely orbital angular momentum are below the conservative torque balance predictions from 40Hz to 200Hz. Assuming a broader range of accretion models, our direct limits on gravitational-wave amplitude delve into the relevant parameter space over a wide range of frequencies, to 500Hz or more

Open data from the third observing run of LIGO, Virgo, KAGRA and GEO

The global network of gravitational-wave observatories now includes five detectors, namely LIGO Hanford, LIGO Livingston, Virgo, KAGRA, and GEO 600. These detectors collected data during their third observing run, O3, composed of three phases: O3a starting in April of 2019 and lasting six months, O3b starting in November of 2019 and lasting five months, and O3GK starting in April of 2020 and lasting 2 weeks. In this paper we describe these data and various other science products that can be freely accessed through the Gravitational Wave Open Science Center at https://gwosc.org. The main dataset, consisting of the gravitational-wave strain time series that contains the astrophysical signals, is released together with supporting data useful for their analysis and documentation, tutorials, as well as analysis software packages.Comment: 27 pages, 3 figure

Search for subsolar-mass black hole binaries in the second part of Advanced LIGO's and Advanced Virgo's third observing run

We describe a search for gravitational waves from compact binaries with atleast one component with mass 0.2 $M_\odot$ -- $1.0 M_\odot$ and mass ratio $q\geq 0.1$ in Advanced LIGO and Advanced Virgo data collected between 1 November2019, 15:00 UTC and 27 March 2020, 17:00 UTC. No signals were detected. Themost significant candidate has a false alarm rate of 0.2 $\mathrm{yr}^{-1}$. Weestimate the sensitivity of our search over the entirety of Advanced LIGO's andAdvanced Virgo's third observing run, and present the most stringent limits todate on the merger rate of binary black holes with at least one subsolar-masscomponent. We use the upper limits to constrain two fiducial scenarios thatcould produce subsolar-mass black holes: primordial black holes (PBH) and amodel of dissipative dark matter. The PBH model uses recent prescriptions forthe merger rate of PBH binaries that include a rate suppression factor toeffectively account for PBH early binary disruptions. If the PBHs aremonochromatically distributed, we can exclude a dark matter fraction in PBHs$f_\mathrm{PBH} \gtrsim 0.6$ (at 90% confidence) in the probed subsolar-massrange. However, if we allow for broad PBH mass distributions we are unable torule out $f_\mathrm{PBH} = 1$. For the dissipative model, where the dark matterhas chemistry that allows a small fraction to cool and collapse into blackholes, we find an upper bound $f_{\mathrm{DBH}} atomic dark matter collapsed into black holes.<br