cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Reconstruction of $α$-attractor supergravity models of inflation
Creators: name: Di Marco, A.
name: Cabella, P.
name: Vittorio, N.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In this paper, we apply reconstruction techniques to recover the potential parameters for a particular class of single-field models, the $α$-attractor (supergravity) models of inflation. This also allows to derive the inflaton vacuum expectation value at horizon crossing. We show how to use this value as one of the input variables to constrain the postaccelerated inflationary phase. We assume that the tensor-to-scalar ratio $r$ is of the order of $10^{-3}$ , a level reachable by the expected sensitivity of the next-generation CMB experiments.
description: 10 pages, LaTeX, some typos corrected
Exploring Galactic open clusters with Gaia I. An examination in the first kiloparsec
Creators: name: Alfonso, Jeison
name: García-Varela, Alejandro
name: Vieira, Katherine
Publisher: name: arXiv
Year: 2024
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Context. Since the first publication of the Gaia catalogue a new view of our Galaxy has arrived. Its astrometric and photometric information has improved the precision of the physical parameters of open star clusters obtained from them. Aims. Using the Gaia DR3 catalogue, we aim to find physical stellar members including faint stars for 370 Galactic open clusters located within 1 kpc. We also estimate the age, metallicity, distance modulus and extinction of these clusters. Methods. We employ the HDBSCAN algorithm on both astrometric and photometric data to identify members in the open clusters. Subsequently, we refine the samples by eliminating outliers through the application of the Mahalanobis metric utilizing the chi-square distribution at a confidence level of 95%. Furthermore, we characterize the stellar parameters with the PARSEC isochrones. Results. We obtain reliable star members for 370 open clusters with an average parallax error of 0.16 mas. We identify about 40% more stars in these clusters compared to previous work using the Gaia DR2 catalogue, including faint stars as new members with G > 17. Before the clustering application we correct the parallax zero-point bias to avoid spatial distribution stretching that may affect clustering results. Our membership lists include merging stars identified by HDBSCAN with astrometry and photometry. We note that the use of photometry in clustering can recover up to 10% more stars in the fainter limit than clustering based on astrometry only, this combined with the selection of stars filtering them out by quality cuts significantly reduces the number of stars with huge parallax error. After clustering, we estimate age, Z, and AV from the photometry of the membership lists.
description: Submitted to A&A. 11 pages, 10 figures
QURILISH MATERIALLARI SANOATI KORXONALARIDAGI INNOVATSION JARAYONLAR SAMARADORLIGINING NAZARIY ASOSLARI
Creators: name: Igamova, Sh.Z.
Publisher: name: Zenodo
Year: 2024

description: Ushbu maqolada qurilish materiallari sanoati korxonalaridagi innovatsion jarayonlar samaradorligining nazariy va uslubiy asoslari va xorij olimlarining fikrlari ko’rib chiqilgan.
New approach to study light-emission of periodic structures. Unveiling novel surface-states effects
Creators: name: Pereyra, Pedro
Publisher: name: arXiv
Year: 2016
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: An accurate approach to calculate the optical response of periodic structures is proposed. Using the genuine superlattice eigenfunctions and energy eigenvalues, the eigenfunctions parity symmetries, the subband symmetries and the detached surface energy levels, we report new optical-transition selection rules and explicit optical-response calculations. Observed transitions that were considered forbidden, become allowed and interesting optical-spectra effects emerge as fingerprints of intra-subband and surface states. The unexplained groups and isolated narrow peaks observed in high resolution blue-laser spectra, by Nakamura et al., are now fully explained and faithfully reproduced
description: 5 pages, 6 figures
Social and moral psychology of COVID-19 across 69 countries
Creators: name: Azevedo, Flavio
name: Pavlović, Tomislav
name: Rêgo, Gabriel G.
name: Ay, F. Ceren
name: Gjoneska, Biljana
name: Etienne, Tom W.
name: Ross, Robert M.
name: Schönegger, Philipp
name: Riaño-Moreno, Julián C.
name: Keudel, Oleksandra
Publisher: name: Freie Universität Berlin
Year: 2023
Subjects: subject: Decision making
subject: Human behaviour
subject: Politics
subject: 300 Sozialwissenschaften::300 Sozialwissenschaften, Soziologie::301 Soziologie, Anthropologie

description: The COVID-19 pandemic has affected all domains of human life, including the economic and social fabric of societies. One of the central strategies for managing public health throughout the pandemic has been through persuasive messaging and collective behaviour change. To help scholars better understand the social and moral psychology behind public health behaviour, we present a dataset comprising of 51,404 individuals from 69 countries. This dataset was collected for the International Collaboration on Social & Moral Psychology of COVID-19 project (ICSMP COVID-19). This social science survey invited participants around the world to complete a series of moral and psychological measures and public health attitudes about COVID-19 during an early phase of the COVID-19 pandemic (between April and June 2020). The survey included seven broad categories of questions: COVID-19 beliefs and compliance behaviours; identity and social attitudes; ideology; health and well-being; moral beliefs and motivation; personality traits; and demographic variables. We report both raw and cleaned data, along with all survey materials, data visualisations, and psychometric evaluations of key variables.
Nonlinear fractional waves at elastic interfaces
Creators: name: Kappler, Julian
name: Shrivastava, Shamit
name: Schneider, Matthias F.
name: Netz, Roland R.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: Biological Physics (physics.bio-ph)
subject: FOS: Physical sciences

description: We derive the nonlinear fractional surface wave equation that governs compression waves at an interface that is coupled to a viscous bulk medium. The fractional character of the differential equation comes from the fact that the effective thickness of the bulk layer that is coupled to the interface is frequency dependent. The nonlinearity arises from the nonlinear dependence of the interface compressibility on the local compression, which is obtained from experimental measurements and reflects a phase transition at the interface. Numerical solutions of our nonlinear fractional theory reproduce several experimental key features of surface waves in phospholipid monolayers at the air-water interface without freely adjustable fitting parameters. In particular, the propagation length of the surface wave abruptly increases at a threshold excitation amplitude. The wave velocity is found to be of the order of 40 cm/s both in experiments and theory and slightly increases as a function of the excitation amplitude. Nonlinear acoustic switching effects in membranes are thus shown to arise purely based on intrinsic membrane properties, namely the presence of compressibility nonlinearities that accompany phase transitions at the interface.
description: 12 pages, 7 figures; supplemental information provided as ancillary file
Evolution of Jupiter and Saturn with helium rain
Creators: name: Howard, Saburo
name: Müller, Simon
name: Helled, Ravit
Publisher: name: arXiv
Year: 2024
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: Phase separation between hydrogen and helium at high pressures and temperatures leads to the rainout of helium in the deep interiors of Jupiter and Saturn. This process, also known as "helium rain", affects their long-term evolution. Therefore, modelling the evolution and internal structure of Jupiter and Saturn (and giant exoplanets) relies on the phase diagram of hydrogen and helium. In this work, we simulate the evolution of Jupiter and Saturn with helium rain by applying different phase diagrams of hydrogen and helium. We find that consistency between Jupiter s evolution and the Galileo measurement of its atmospheric helium abundance is achieved only if a shift in temperature in the existing phase diagrams is applied (-1250 K, +350 K or -3850 K depending on the used phase diagram). We next use the shifted phase diagrams to model Saturn s evolution and find consistent solutions for both planets. We confirm that demixing in Jupiter is modest while in Saturn, the process of helium rain is significant. We find that Saturn has a large helium gradient and a helium ocean. Saturn s atmospheric helium mass fraction is estimated to be between 0.13 and 0.16. We also investigate how the used hydrogen-helium equation of state and atmospheric model affect the planetary evolution and find that the predicted cooling times can change by several hundred million years. Constraining the level of super-adiabaticity in the helium gradient formed in Jupiter and Saturn remains challenging and should be investigated in detail in future research. We conclude that further explorations of the immiscibility between hydrogen and helium are valuable as this knowledge directly affects the evolution and current-state structure of Jupiter and Saturn. Finally, we argue that measuring Saturn s atmospheric helium content is crucial for constraining Saturn s evolution as well as the hydrogen-helium phase diagram.
description: Accepted for publication in A&A
Quantum Monte Carlo Annealing with Multi-Spin Dynamics
Creators: name: Mazzola, Guglielmo
name: Troyer, Matthias
Publisher: name: arXiv
Year: 2017
Subjects: subject: Quantum Physics (quant-ph)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We introduce a novel Simulated Quantum Annealing (SQA) algorithm which employs a multispin quantum fluctuation operator. At variance with the usual transverse field, short-range two-spin flip interactions are included in the driver Hamiltonian. A Quantum Monte Carlo algorithm, capable of efficiently simulating large disordered systems, is described and tested. A first application to SQA, on a random square lattice Ising spin glass reveals that the multi-spin driver Hamiltonian improves upon the usual transverse field. This work paves the way for more systematic investigations using multi-spin quantum fluctuations on a broader range of problems.
MARJONBULOQ TEXNOGEN BUZILGAN YERLARINING EKOLOGIK XOLATI
Creators: name: Rahmonova, U.T.
Publisher: name: Zenodo
Year: 2024

description: Bugungi kunda metallurgiyaning rivojlanishi, xom- ashyodan kompleks foydalanish atrof – muhitni va mehnatni muhofaza qilishning umumiy masalalariga chambarchas bog’liqdir. O’zbekiston Respublikasining qarori 24.06.2021- yildagi PQ-5159 son,Kon metallurgiya sanoati va unga bog’liq sohalarni rivojlantirish bo’yicha qo’shimcha chora tadbirlar to’g’risidagi O’zbekiston Respublikasi Prezidentining Farmoni,30.10.2019- yildagi PF-5863 son va 2030-yilgacha bo’lgan davrda O’zbekiston Respublikasining atrof muhitni muhofaza qilish konsepsiyasidan kelib chiqqan holda Marjonbuloq oltin qazib olish tog’-kon sanoati chiqindilarining xosil bo’lish  xajmlarini kamaytirish,hamda mavjud xajmlarini qisqartirish,shu jumladan xavfli chiqindilarning aholi salomatligiga va atrof muhitga salbiy ta’sirining oldini olish,ekologik jihatdan  xavfsiz saqlanishini tashkil etishni ta’minlash dolzarb muammolardan biri hisoblanadi.
Optimal Tree Tensor Network Operators for Tensor Network Simulations: Applications to Open Quantum Systems
Creators: name: Li, Weitang
name: Ren, Jiajun
name: Yang, Hengrui
name: Wang, Haobin
name: Shuai, Zhigang
Publisher: name: arXiv
Year: 2024
Subjects: subject: Quantum Physics (quant-ph)
subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: Tree tensor network states (TTNS) decompose the system wavefunction to the product of low-rank tensors based on the tree topology, serving as the foundation of the multi-layer multi-configuration time-dependent Hartree (ML-MCTDH) method. In this work, we present an algorithm that automatically constructs the optimal and exact tree tensor network operators (TTNO) for any sum-of-product symbolic quantum operator.The construction is based on the minimum vertex cover of a bipartite graph. With the optimal TTNO, we simulate open quantum systems such as spin relaxation dynamics in the spin-boson model and charge transport in molecular junctions. In these simulations, the environment is treated as discrete modes and its wavefunction is evolved on equal footing with the system. We employ the Cole-Davidson spectral density to model the glassy phonon environment, and incorporate temperature effects via thermo field dynamics. Our results show that the computational cost scales linearly with the number of discretized modes, demonstrating the efficiency of our approach.
Quantum critical response: from conformal perturbation theory to holography
Creators: name: Lucas, Andrew
name: Sierens, Todd
name: Witczak-Krempa, William
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We discuss dynamical response functions near quantum critical points, allowing for both a finite temperature and detuning by a relevant operator. When the quantum critical point is described by a conformal field theory (CFT), conformal perturbation theory and the operator product expansion can be used to fix the first few leading terms at high frequencies. Knowledge of the high frequency response allows us then to derive non-perturbative sum rules. We show, via explicit computations, how holography recovers the general results of CFT, and the associated sum rules, for any holographic field theory with a conformal UV completion -- regardless of any possible new ordering and/or scaling physics in the IR. We numerically obtain holographic response functions at all frequencies, allowing us to probe the breakdown of the asymptotic high-frequency regime. Finally, we show that high frequency response functions in holographic Lifshitz theories are quite similar to their conformal counterparts, even though they are not strongly constrained by symmetry.
description: 45+14 pages, 9 figures. v2: small clarifications, added references
INFORMATION RADIOLOGY DIAGNOSTICS IN TRAUMATOLOGY
Creators: name: Ismailov, Kh.Kh.
Publisher: name: Zenodo
Year: 2024

description: The rapid development of diagnostic radiology observed in the last two decades has opened up fundamentally new opportunities for clinical medicine, making almost all organs and tissue structures of the human body available for research. Radiation research methods have long been in second place in terms of the frequency of their use, second only to the most common and mandatory laboratory tests. Classical radiology in many areas of surgery, therapy, and cardiology no longer plays a leading role in the production of medical images. According to WHO, about 80% of diagnoses are made through the direct use of radiation research materials. In this regard, modern radiation diagnostics, which has various methods of visual control, is increasingly focused on comprehensive solutions to diagnostic and therapeutic problems using new methods. 100% of orthopedic and traumatology patients require examinations using radiological diagnostic methods.
Imaging of exocomets with infrared interferometry
Creators: name: Janson, Markus
name: Patel, Jayshil
name: Ringqvist, Simon C.
name: Lu, Cicero
name: Rebollido, Isabel
name: Lichtenberg, Tim
name: Brandeker, Alexis
name: Angerhausen, Daniel
name: Noack, Lena
Publisher: name: Freie Universität Berlin
Year: 2023
Subjects: subject: infrared: planetary systems
subject: comets: general
subject: planets and satellites: detection
subject: 500 Naturwissenschaften und Mathematik::520 Astronomie::520 Astronomie und zugeordnete Wissenschaften

description: Active comets have been detected in several exoplanetary systems, although so far only indirectly, when the dust or gas in the extended coma has transited in front of the stellar disk. The large optical surface and relatively high temperature of an active cometary coma also makes it suitable to study with direct imaging, but the angular separation is generally too small to be reachable with present-day facilities. However, future imaging facilities with the ability to detect terrestrial planets in the habitable zones of nearby systems will also be sensitive to exocomets in such systems. Here we examine several aspects of exocomet imaging, particularly in the context of the Large Interferometer for Exoplanets (LIFE), which is a proposed space mission for infrared imaging and spectroscopy through nulling interferometry. We study what capabilities LIFE would have for acquiring imaging and spectroscopy of exocomets, based on simulations of the LIFE performance as well as statistical properties of exocomets that have recently been deduced from transit surveys. We find that for systems with extreme cometary activities such as β Pictoris, sufficiently bright comets may be so abundant that they overcrowd the LIFE inner field of view. More nearby and moderately active systems such as є Eridani or Fomalhaut may turn out to be optimal targets. If the exocomets have strong silicate emission features, such as in comet Hale-Bopp, it may become possible to study the mineralogy of individual exocometary bodies. We also discuss the possibility of exocomets as false positives for planets, with recent deep imaging of α Centauri as one hypothetical example. Such contaminants could be common, primarily among young debris disk stars, but should be rare among the main sequence population. We discuss strategies to mitigate the risk of any such false positives.
title: Development of a cell-free strategy for the directed evolution of enzymes for high-value natural products
Creators: name: Harman, Joshua
Publisher: name: University of Kent
Year: 2022

description: Cell-free protein synthesis (CFPS) provides a robust method for protein production in a system in which all the contained energy can be channelled toward protein synthesis by removing the life goals of the cell. Herein, we sought to produce the haem dependant cytochrome P45enzyme BM3 using a cell-free system as a proof of concept that complex cytochrome P450 enzymes can be studied using this technique and to provide a foundation for further study into directed evolution. To facilitate the production of BM3 in a cell-free reaction, we optimised a CFPS methodology by varying the reaction composition and expressed and characterised the BM3 protein using in vivo methods to act as a positive control. We observed several conditions that affect CFPS activity including, Mg2+, L-glutamate, maltodextrin, and D-ribose. However, while E. coli in vivo production of BM3 was strong, in contrast, the optimised E. coli CFPS system was unable to synthesise BM3. This could be due to several factors, including low promoter strength or low extract activity. In parallel, we also sought to produce a cell-free system for making haem the prosthetic group required for BM3 activity. Therefore, we expressed and characterised the enzymes for cell-free haem biosynthesis. Intriguingly, in an attempt to make haem b, instead, intermediates such as coproporphyrinogen III were formed. We suggest that either one of the enzymes was limiting (HemH - ferrochelatase), or a co-factor was absent in the reaction. In this research we were unable to synthesise BM3 using CFPS, this is most likely due to the low activity of the extract, by further refining the crude extract production method and the composition of the cell-free reaction it may be possible to produce BM3.
Mechanisms of amyloid-β34 generation indicate a pivotal role for BACE1 in amyloid homeostasis
Creators: name: Ulku, Irem
name: Liebsch, Filip
name: Akerman, S. Can
name: Schulz, Jana F.
name: Kulic, Luka
name: Hock, Christoph
name: Pietrzik, Claus
name: Di Spiezio, Alessandro
name: Thinakaran, Gopal
name: Saftig, Paul
Publisher: name: Freie Universität Berlin
Year: 2023
Subjects: subject: Biochemistry
subject: Biological techniques
subject: Cell biology
subject: 500 Naturwissenschaften und Mathematik::570 Biowissenschaften; Biologie::570 Biowissenschaften; Biologie

description: The beta‑site amyloid precursor protein (APP) cleaving enzyme (BACE1) was discovered due to its “amyloidogenic” activity which contributes to the production of amyloid-beta (Aβ) peptides. However, BACE1 also possesses an “amyloidolytic” activity, whereby it degrades longer Aβ peptides into a non‑toxic Aβ34 intermediate. Here, we examine conditions that shift the equilibrium between BACE1 amyloidogenic and amyloidolytic activities by altering BACE1/APP ratios. In Alzheimer disease brain tissue, we found an association between elevated levels of BACE1 and Aβ34. In mice, the deletion of one BACE1 gene copy reduced BACE1 amyloidolytic activity by ~ 50%. In cells, a stepwise increase of BACE1 but not APP expression promoted amyloidolytic cleavage resulting in dose-dependently increased Aβ34 levels. At the cellular level, a mislocalization of surplus BACE1 caused a reduction in Aβ34 levels. To align the role of γ-secretase in this pathway, we silenced Presenilin (PS) expression and identified PS2-γ-secretase as the main γ-secretase that generates Aβ40 and Aβ42 peptides serving as substrates for BACE1’s amyloidolytic cleavage to generate Aβ34.
Emergent Causality and the N-photon Scattering Matrix in Waveguide QED
Creators: name: Sánchez-Burillo, Eduardo
name: Cadarso, Andrea
name: Martín-Moreno, Luis
name: García-Ripoll, Juan José
name: Zueco, David
Publisher: name: arXiv
Year: 2017
Subjects: subject: Quantum Physics (quant-ph)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: In this work we discuss the emergence of approximate causality in a general setup from waveguide QED -i.e. a one-dimensional propagating field interacting with a scatterer. We prove that this emergent causality translates into a structure for the N-photon scattering matrix. Our work builds on the derivation of a Lieb-Robinson-type bound for continuous models and for all coupling strengths, as well as on several intermediate results, of which we highlight (i) the asymptotic independence of space-like separated wave packets, (ii) the proper definition of input and output scattering states, and (iii) the characterization of the ground state and correlations in the model. We illustrate our formal results by analyzing the two-photon scattering from a quantum impurity in the ultrastrong coupling regime, verifying the cluster decomposition and ground-state nature. Besides, we generalize the cluster decomposition if inelastic or Raman scattering occurs, finding the structure of the S-matrix in momentum space for linear dispersion relations. In this case, we compute the decay of the fluorescence (photon-photon correlations) caused by this S-matrix.
Climate Change in Hell: Long-Term Variation in Transits of the Evaporating Planet K2-22b
Creators: name: Gaidos, E.
name: Parviainen, H.
name: Esparza-Borges, E.
name: Fukui, A.
name: Isogai, K.
name: Kawauchi, K.
name: de Leon, J.
name: Mori, M.
name: Murgas, F.
name: Narita, N.
name: Palle, E.
name: Watanabe, N.
Publisher: name: arXiv
Year: 2024
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: Context: Rocky planets on ultra-short period orbits can have surface magma oceans and rock-vapour atmospheres in which dust can condense. Observations of that dust can inform about the composition surface conditions on these objects. Aims: We constrain the properties and long-term (decade) behaviour of the transiting dust cloud from the "evaporating" planet K2-22b. Methods: We observed K2-22b around 40 predicted transits with MuSCAT ground-based multi-optical channel imagers, and complemented these data with long-term monitoring by the ground-based ATLAS (2018-2024) and space-based TESS (2021-2023) surveys. Results: We detected signals during 7 transits, none of which showed significant wavelength dependence. The expected number of MuSCAT-detected transits is >=22, indicating a decline in mean transit depth since the K2 discovery observations in 2014. Conclusions: Lack of significant wavelength dependence indicates that dust grains are large or the cloud is optically thick. Long-term trends of depth could be due to a magnetic cycle on the host star or overturn of the planet's dayside surface magma ocean. The possibility that K2-22b is disappearing altogether is ruled out by the stability of the transit ephemeris against non-gravitational forces, which constrains the mass to be at least comparable to Ceres.
description: accepted to Astronomy and Astrophysics Letters
Review article: A European perspective on wind and storm damage – from the meteorological background to index-based approaches to assess impacts
Creators: name: Gliksman, Daniel
name: Averbeck, Paul
name: Becker, Nico
name: Gardiner, Barry
name: Goldberg, Valeri
name: Grieger, Jens
name: Handorf, Doerthe
name: Haustein, Karsten
name: Karwat, Alexia
name: Knutzen, Florian
Publisher: name: Freie Universität Berlin
Year: 2023
Subjects: subject: wind and storm damage
subject: meteorological background
subject: index-based approaches
subject: 500 Naturwissenschaften und Mathematik::550 Geowissenschaften, Geologie::550 Geowissenschaften

description: Wind and windstorms cause severe damage to natural and human-made environments. Thus, wind-related risk assessment is vital for the preparation and mitigation of calamities. However, the cascade of events leading to damage depends on many factors that are environment-specific and the available methods to address wind-related damage often require sophisticated analysis and specialization. Fortunately, simple indices and thresholds are as effective as complex mechanistic models for many applications. Nonetheless, the multitude of indices and thresholds available requires a careful selection process according to the target sector. Here, we first provide a basic background on wind and storm formation and characteristics, followed by a comprehensive collection of both indices and thresholds that can be used to predict the occurrence and magnitude of wind and storm damage. We focused on five key sectors: forests, urban areas, transport, agriculture and wind-based energy production. For each sector we described indices and thresholds relating to physical properties such as topography and land cover but also to economic aspects (e.g. disruptions in transportation or energy production). In the face of increased climatic variability, the promotion of more effective analysis of wind and storm damage could reduce the impact on society and the environment.
Variable interstellar radiation fields in simulated dwarf galaxies: supernovae versus photoelectric heating
Creators: name: Hu, Chia-Yu
name: Naab, Thorsten
name: Glover, Simon C. O.
name: Walch, Stefanie
name: Clark, Paul C.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We present high-resolution hydrodynamical simulations of isolated dwarf galaxies including self-gravity, non-equilibrium cooling and chemistry, interstellar radiation fields (IRSF) and shielding, star formation, and stellar feedback. This includes spatially and temporally varying photoelectric (PE) heating, photoionization, resolved supernova (SN) blast waves and metal enrichment. A new flexible method to sample the stellar initial mass function allows us to follow the contribution to the ISRF, the metal output and the SN delay times of individual massive stars. We find that SNe play the dominant role in regulating the global star formation rate, shaping the multi-phase interstellar medium (ISM) and driving galactic outflows. Outflow rates (with mass-loading factors of a few) and hot gas fractions of the ISM increase with the number of SNe exploding in low-density environments where radiative energy losses are low. While PE heating alone can suppress star formation slightly more (a factor of a few) than SNe alone can do, it is unable to drive outflows and reproduce the multi-phase ISM that emerges naturally when SNe are included. These results are in conflict with recent results of Forbes et al. who concluded that PE heating is the dominant process suppressing star formation in dwarfs, about an order of magnitude more efficient than SNe. Potential origins for this discrepancy are discussed. In the absence of SNe and photoionization (mechanisms to disperse dense clouds), the impact of PE heating is highly overestimated owing to the (unrealistic) proximity of dense gas to the radiation sources. This leads to a substantial boost of the infrared continuum emission from the UV-irradiated dust and a far infrared line-to-continuum ratio too low compared to observations. Though sub-dominant in regulating star formation, the ISRF controls the abundance of molecular hydrogen via photodissociation.
description: submitted, comments welcome
Global Protected Areas as refuges for amphibians and reptiles under climate change
Creators: name: Mi, Chunrong
name: Ma, Liang
name: Yang, Mengyuan
name: Li, Xinhai
name: Meiri, Shai
name: Roll, Uri
name: Oskyrko, Oleksandra
name: Pincheira-Donoso, Daniel
name: Harvey, Lilly P.
name: Itescu, Yuval
Publisher: name: Freie Universität Berlin
Year: 2023
Subjects: subject: Conservation biology
subject: Environmental impact
subject: climate change
subject: 500 Naturwissenschaften und Mathematik::570 Biowissenschaften; Biologie::570 Biowissenschaften; Biologie

description: Protected Areas (PAs) are the cornerstone of biodiversity conservation. Here, we collated distributional data for >14,000 (~70% of) species of amphibians and reptiles (herpetofauna) to perform a global assessment of the conservation effectiveness of PAs using species distribution models. Our analyses reveal that >91% of herpetofauna species are currently distributed in PAs, and that this proportion will remain unaltered under future climate change. Indeed, loss of species’ distributional ranges will be lower inside PAs than outside them. Therefore, the proportion of effectively protected species is predicted to increase. However, over 7.8% of species currently occur outside PAs, and large spatial conservation gaps remain, mainly across tropical and subtropical moist broadleaf forests, and across non-high-income countries. We also predict that more than 300 amphibian and 500 reptile species may go extinct under climate change over the course of the ongoing century. Our study highlights the importance of PAs in providing herpetofauna with refuge from climate change, and suggests ways to optimize PAs to better conserve biodiversity worldwide.
Physically-based Path Tracer using WebGPU and OpenPBR
Creators: name: Stucki, Simon
name: Ackermann, Philipp
Publisher: name: arXiv
Year: 2024
Subjects: subject: Graphics (cs.GR)
subject: FOS: Computer and information sciences

description: This work presents a web-based, open-source path tracer for rendering physically-based 3D scenes using WebGPU and the OpenPBR surface shading model. While rasterization has been the dominant real-time rendering technique on the web since WebGL's introduction in 2011, it struggles with global illumination. This necessitates more complex techniques, often relying on pregenerated artifacts to attain the desired level of visual fidelity. Path tracing inherently addresses these limitations but at the cost of increased rendering time. Our work focuses on industrial applications where highly customizable products are common and real-time performance is not critical. We leverage WebGPU to implement path tracing on the web, integrating the OpenPBR standard for physically-based material representation. The result is a near real-time path tracer capable of rendering high-fidelity 3D scenes directly in web browsers, eliminating the need for pregenerated assets. Our implementation demonstrates the potential of WebGPU for advanced rendering techniques and opens new possibilities for web-based 3D visualization in industrial applications.
description: pre-print version
A Heterogeneous FMM for 2-D Layered Media Helmholtz Equation I: Two & Three Layers Cases
Creators: name: Cho, Min Hyung
name: Huang, Jingfang
name: Chen, Dangxing
name: Cai, Wei
Publisher: name: arXiv
Year: 2017
Subjects: subject: Numerical Analysis (math.NA)
subject: FOS: Mathematics

description: In this paper, we will introduce a new heterogeneous fast multipole method (H-FMM) for 2-D Helmholtz equation in layered media. To illustrate the main algorithm ideas, we focus on the case of two and three layers in this work. The key compression step in the H-FMM is based on a fact that the multipole expansion for the sources of the free-space Green's function can be used also to compress the far field of the sources of the layered-media or domain Green's function, and a similar result exists for the translation operators for the multipole and local expansions. The mathematical error analysis is shown rigorously by an image representation of the Sommerfeld spectral form of the domain Green's function. As a result, in the H-FMM algorithm, both the "multipole-to-multipole" and "local-to-local" translation operators are the same as those in the free-space case, allowing easy adaptation of existing free-space FMM. All the spatially variant information of the domain Green's function are collected into the "multipole-to-local" translations and therefore the FMM becomes "heterogeneous". The compressed representation further reduces the cost of evaluating the domain Green's function when computing the local direct interactions. Preliminary numerical experiments are presented to demonstrate the efficiency and accuracy of the algorithm with much improved performance over some existing methods for inhomogeneous media. Furthermore, we also show that, due to the equivalence between the complex line image representation and Sommerfeld integral representation of layered media Green's function, the new algorithm can be generalized to multi-layered media with minor modification where details for compression formulas, translation operators, and bookkeeping strategies will be addressed in a subsequent paper.
Decoupling gravitational sources in general relativity: from perfect to anisotropic fluids
Creators: name: Ovalle, Jorge
Publisher: name: arXiv
Year: 2017
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We show the first simple, systematic and direct approach to decoupling gravitational sources in general relativity. As a direct application, a robust and simple way to generate anisotropic solutions for self-gravitating systems from perfect fluid solutions is presented.
description: 5 pages, typos corrected
Micrometeoroid infall onto Saturn’s rings constrains their age to no more than a few hundred million years
Creators: name: Kempf, Sascha
name: Altobelli, Nicolas
name: Schmidt, Jürgen
name: Cuzzi, Jeffrey N.
name: Estrada, Paul R.
name: Srama, Ralf
Publisher: name: Freie Universität Berlin
Year: 2023
Subjects: subject: Saturn’s rings
subject: age
subject: micrometeoroid infall
subject: 500 Naturwissenschaften und Mathematik::520 Astronomie::520 Astronomie und zugeordnete Wissenschaften

description: There is ongoing debate as to whether Saturn’s main rings are relatively young or ancient— having been formed shortly after Saturn or during the Late Heavy Bombardment. The rings are mostly water-ice but are polluted by non-icy material with a volume fraction ranging from ∼0.1 to 2%. Continuous bombardment by micrometeoroids exogenic to the Saturnian system is a source of this non-icy material. Knowledge of the incoming mass flux of these pollutants allows estimation of the rings’ exposure time, providing a limit on their age. Here we report the final measurements by Cassini’s Cosmic Dust Analyzer of the micrometeoroid flux into the Saturnian system. Several populations are present, but the flux is dominated by low-relative velocity objects such as from the Kuiper belt. We find a mass flux between 6.9 · 10−17 and 2.7 · 10−16 kg m−2s−1 from which we infer a ring exposure time ≲100 to 400 million years in support of recent ring formation scenarios.
Magnetic ordering of the Mo$_3$O$_8$-type cluster Mott insulator Na$_3$Sc$_2$(MoO$_4$)$_2$Mo$_3$O$_8$ with spin-1/2 triangular lattice prepared via optimal synthesis
Creators: name: Haraguchi, Yuya
name: Ishikita, Daigo
name: Katori, Hiroko Aruga
Publisher: name: arXiv
Year: 2024
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We detail the optimized synthesis of the Mo$_3$O$_8$-type cluster Mott insulator (CMI) Na$_3$Sc$_2$(MoO$_4$)$_2$Mo$_3$O$_8$, which has been considered a candidate for realizing the spin liquid ground state. The optimized Na$_3$Sc$_2$(MoO$_4$)$_2$Mo$_3$O$_8$, characterized by x-ray diffraction, energy-dispersive x-ray spectroscopy, and magnetic and heat capacity measurements, exhibited an effective magnetic moment close to the ideal 1.73 $μ_{\mathrm B}$ for $S = 1/2$ spin and magnetic ordering at $\sim$ 5 K. These observations categorize Na$_3$Sc$_2$(MoO$_4$)$_2$Mo$_3$O$_8$ as the second Mo$_3$O$_8$-type CMI to achieve a magnetic ground state, following Li$_2$InMo$_3$O$_8$. They highlight the stabilization of the magnetic ground state over the theoretically anticipated quantum spin liquid state through precise valence and chemical disorder tuning. Our findings challenge the existing theory that the magnetic ground state of Mo$_3$O$_8$-type CMIs is determined by the breathing parameter, instead showing that magnetic order is suppressed by spin defects. This study underscores the crucial role of chemical precision in investigating quantum magnetism. It suggests that precise tuning of valence states could induce magnetic ordering in previously nonmagnetic Mo$_3$O$_8$-type CMIs. Additionally, the negative findings regarding the existence of quantum spin liquids highlight the need for applied research and a reevaluation of our fundamental understanding of electronic states from both theoretical and experimental aspects.
description: 8 pages, 5 figures, accepted in Physical Review Materials
A Useful Solution of the Coupon Collector's Problem
Creators: name: Braband, Niklas
name: Braband, Sonja
name: Braband, Malte
Publisher: name: arXiv
Year: 2017
Subjects: subject: History and Overview (math.HO)
subject: Probability (math.PR)
subject: FOS: Mathematics

description: The Coupon Collector's Problem is one of the few mathematical problems that make news headlines regularly. The reasons for this are on one hand the immense popularity of soccer albums (called Paninimania) and on the other hand that no solution is known that is able to take into account all effects such as replacement (limited purchasing of missing stickers) or swapping. In previous papers we have proven that the classical assumptions are not fulfilled in practice. Therefore we define new assumptions that match reality. Based on these assumptions we are able to derive formulae for the mean number of stickers needed (and the associated standard deviation) that are able to take into account all effects that occur in practical collecting. Thus collectors can estimate the average cost of completion of an album and its standard deviation just based on elementary calculations. From a practical point of view we consider the Coupon Collector's problem as solved. ----- Das Sammelbilderproblem ist eines der wenigen mathematischen Probleme, die regelmäßig in den Schlagzeilen der Nachrichten vorkommen. Dies liegt einerseits an der großen Popularität von Fußball-Sammelbildern (Paninimania genannt) und andererseits daran, dass es bisher keine Lösung gibt, die alle relevanten Effekte wie Nachkaufen oder Tauschen berücksichtigt. Wir haben bereits nachgewiesen, dass die klassischen Annahmen nicht der Realität entsprechen. Deshalb stellen wir neue Annahmen auf, die die Praxis besser abbilden. Darauf aufbauend können wir Formeln für die mittlere Anzahl benötigter Bilder (sowie deren Standardabweichung) ableiten, die alle in der Praxis relevanten Effekte berücksichtigen. Damit können Sammler die mittleren Kosten eines Albums sowie deren Standardabweichung nur mit Hilfe von elementaren Rechnungen bestimmen. Für praktische Zwecke ist das Sammelbilderproblem damit gelöst.
description: 14 pages, 1 figure, in German
An Efficient Convex-Hull Relaxation Based Algorithm for Multi-User Discrete Passive Beamforming
Creators: name: Lai, Wenhai
name: Wu, Zheyu
name: Feng, Yi
name: Shen, Kaiming
name: Liu, Ya-Feng
Publisher: name: arXiv
Year: 2024
Subjects: subject: Information Theory (cs.IT)
subject: Signal Processing (eess.SP)
subject: FOS: Computer and information sciences
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: Intelligent reflecting surface (IRS) is an emerging technology to enhance spatial multiplexing in wireless networks. This letter considers the discrete passive beamforming design for IRS in order to maximize the minimum signal-to-interference-plus-noise ratio (SINR) among multiple users in an IRS-assisted downlink network. The main design difficulty lies in the discrete phase-shift constraint. Differing from most existing works, this letter advocates a convex-hull relaxation of the discrete constraints which leads to a continuous reformulated problem equivalent to the original discrete problem. This letter further proposes an efficient alternating projection/proximal gradient descent and ascent algorithm for solving the reformulated problem. Simulation results show that the proposed algorithm outperforms the state-of-the-art methods significantly.
description: 5 pages
Unveiling slim accretion disc in AGN through X-ray and Infrared observations
Creators: name: Castelló-Mor, Núria
name: Kaspi, Shai
name: Netzer, Hagai
name: Du, Pu
name: Hu, Chen
name: Ho, Luis C.
name: Bai, Jin-Ming
name: Bian, Wei-Hao
name: Yuan, Ye-Fei
name: Wang, Jian-Min
Publisher: name: arXiv
Year: 2017
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: In this work, which is a continuation of Castelló-Mor et al. (2016), we present new X-ray and infrared (IR) data for a sample of active galactic nuclei (AGN) covering a wide range in Eddington ratio over a small luminosity range. In particular, we rigorously explore the dependence of the optical-to-X-ray spectral index $α_{OX}$ and the IR-to-optical spectral index on the dimensionless accretion rate, $\dot{\mathcal{M}}=\dot{m}/η$ where $\dot{m}=L_{AGN}/L_{Edd}$ and $η$ is the mass-to-radiation conversion efficiency, in low and high accretion rate sources. We find that the SED of the faster accreting sources are surprisingly similar to those from the comparison sample of sources with lower accretion rate. In particular: i) the optical-to-UV AGN SED of slow and fast accreting AGN can be fitted with thin AD models. ii) The value of $α_{OX}$ is very similar in slow and fast accreting systems up to a dimensionless accretion rate $\dot{\mathcal{M}}_{c}\sim$10. We only find a correlation between $α_{OX}$ and $\dot{\mathcal{M}}$ for sources with $\dot{\mathcal{M}} > \dot{\mathcal{M}}_{c}$. In such cases, the faster accreting sources appear to have systematically larger $α_{OX}$ values. iii) We also find that the torus in the faster accreting systems seems to be less efficient in reprocessing the primary AGN radiation having lower IR-to-optical spectral slopes. These findings, failing to recover the predicted differences between the SEDs of slim and thin ADs within the observed spectral window, suggest that additional physical processes or very special geometry act to reduce the extreme UV radiation in fast accreting AGN. This may be related to photon trapping, strong winds, and perhaps other yet unknown physical processes.
description: Accepted for publication on MNRAS, 14 pages, 7 figures
УЛЬТРАЗВУКОВАЯ  ИССЛЕДОВАНИЯ СТЕНКИ ЖЕЛЧНОГО ПУЗЫРЯ ПРИ ХОЛЕЦИСТИТАХ
Creators: name: Исмоилов, Х.Х.
name: Жумаева, М.М.
Publisher: name: Zenodo
Year: 2024

description: В настоящее время острый холецистит является одним из наиболее распространенныхострых хирургических заболеваний органов брюшной  полости [1, 2, 5]. Важное значение имеет создание лабораторных панелей оценки степени тяжести и остроты патологического процесса при обострении хронических или скрыто протекающих форм этого заболевания. Отмечается тенденция к увеличению развития скрытых гнойно-деструктивных форм острого холецистита со скудной симптоматикой, что может быть связано мощной антибактериальной и многоцелевой инфузионной терапии, которые значительно изменяют клиническую картину заболевания, нивелируют острые проявления деструктивного холецистита, в том числе клинико-лабораторные признаки эндогенной интоксикации, создавая ложное впечатление о регрессивном течении заболевания. Исследование клинико-морфологических особенностей малосимптомных форм холецистита может помочь в понимании механизмов их развития, что будет полезным для выделения групп риска по развитию малосимптомных форм острого деструктивного холецистита и оптимизации тактики ведения таких пациентов.
U2UData: A Large-scale Cooperative Perception Dataset for Swarm UAVs Autonomous Flight
Creators: name: Feng, Tongtong
name: Wang, Xin
name: Han, Feilin
name: Zhang, Leping
name: Zhu, Wenwu
Publisher: name: arXiv
Year: 2024
Subjects: subject: Robotics (cs.RO)
subject: FOS: Computer and information sciences

description: Modern perception systems for autonomous flight are sensitive to occlusion and have limited long-range capability, which is a key bottleneck in improving low-altitude economic task performance. Recent research has shown that the UAV-to-UAV (U2U) cooperative perception system has great potential to revolutionize the autonomous flight industry. However, the lack of a large-scale dataset is hindering progress in this area. This paper presents U2UData, the first large-scale cooperative perception dataset for swarm UAVs autonomous flight. The dataset was collected by three UAVs flying autonomously in the U2USim, covering a 9 km$^2$ flight area. It comprises 315K LiDAR frames, 945K RGB and depth frames, and 2.41M annotated 3D bounding boxes for 3 classes. It also includes brightness, temperature, humidity, smoke, and airflow values covering all flight routes. U2USim is the first real-world mapping swarm UAVs simulation environment. It takes Yunnan Province as the prototype and includes 4 terrains, 7 weather conditions, and 8 sensor types. U2UData introduces two perception tasks: cooperative 3D object detection and cooperative 3D object tracking. This paper provides comprehensive benchmarks of recent cooperative perception algorithms on these tasks.
description: Accepted by ACM MM24