cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Different dust and gas radial extents in protoplanetary disks: consistent models of grain growth and CO emission
Creators: name: Facchini, Stefano
name: Birnstiel, Til
name: Bruderer, Simon
name: van Dishoeck, Ewine F.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: ALMA observations of protoplanetary disks confirm earlier indications that there is a clear difference between the dust and gas radial extents. The origin of this difference is still debated, with both radial drift of the dust and optical depth effects suggested in the literature. In this work, the feedback of realistic dust particle distributions onto the gas chemistry and molecular emissivity is investigated, with a particular focus on CO isotopologues. The radial dust grain size distribution is determined using dust evolution models that include growth, fragmentation and radial drift. A new version of the code DALI is used to take into account how dust surface area and density influence the disk thermal structure, molecular abundances and excitation. The difference of dust and gas radial sizes is largely due to differences in the optical depth of CO lines and millimeter continuum, without the need to invoke radial drift. The effect of radial drift is primarily visible in the sharp outer edge of the continuum intensity profile. The gas outer radius probed by $^{12}$CO emission can easily differ by a factor of $\sim 2$ between the models for a turbulent $α$ ranging between typical values. Grain growth and settling concur in thermally decoupling the gas and dust components, due to the low collision rate with large grains. As a result, the gas can be much colder than the dust at intermediate heights, reducing the CO excitation and emission, especially for low turbulence values. Also, due to disk mid-plane shadowing, a second CO thermal desorption (rather than photodesorption) front can occur in the warmer outer mid-plane disk. The models are compared to ALMA observations of HD 163296 as a test case. In order to reproduce the observed CO snowline of the system, a binding energy for CO typical of ice mixtures needs to be used rather than the lower pure CO value.
description: 26 pages, 25 figures, accepted for publication in A&A, abstract shortened to fit arXiv requirements
K$^{*}(892)^{0}$ and $ϕ(1020)$ meson production at high transverse momentum in pp and Pb-Pb collisions at $\sqrt{s_\mathrm{NN}}$ = 2.76 TeV
Creators: name: ALICE Collaboration
Publisher: name: arXiv
Year: 2017
Subjects: subject: Nuclear Experiment (nucl-ex)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: The production of K$^{*}(892)^{0}$ and $ϕ(1020)$ mesons in proton-proton (pp) and lead-lead (Pb-Pb) collisions at $\sqrt{s_\mathrm{NN}} =$ 2.76 TeV has been analyzed using a high luminosity data sample accumulated in 2011 with the ALICE detector at the Large Hadron Collider (LHC). Transverse momentum ($p_{\mathrm{T}}$) spectra have been measured for K$^{*}(892)^{0}$ and $ϕ(1020)$ mesons via their hadronic decay channels for $p_{\mathrm{T}}$ up to 20 GeV/$c$. The measurements in pp collisions have been compared to model calculations and used to determine the nuclear modification factor and particle ratios. The K$^{*}(892)^{0}$/K ratio exhibits significant reduction from pp to central Pb-Pb collisions, consistent with the suppression of the K$^{*}(892)^{0}$ yield at low $p_{\mathrm{T}}$ due to rescattering of its decay products in the hadronic phase. In central Pb-Pb collisions the $p_{\mathrm{T}}$ dependent $ϕ(1020)/π$ and K$^{*}(892)^{0}$/$π$ ratios show an enhancement over pp collisions for $p_{\mathrm{T}}$ $\sim$3 GeV/$c$, consistent with previous observations of strong radial flow. At high $p_{\mathrm{T}}$, particle ratios in Pb-Pb collisions are similar to those measured in pp collisions. In central Pb-Pb collisions, the production of K$^{*}(892)^{0}$ and $ϕ(1020)$ mesons is suppressed for $p_{\mathrm{T}}> 8$ GeV/$c$. This suppression is similar to that of charged pions, kaons and protons, indicating that the suppression does not depend on particle mass or flavor in the light quark sector.
description: 26 pages, 10 captioned figures, 3 tables, authors from page 21, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/3363
Emergence of a control parameter for the antiferromagnetic quantum critical metal
Creators: name: Lunts, Peter
name: Schlief, Andres
name: Lee, Sung-Sik
Publisher: name: arXiv
Year: 2017
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We study the antiferromagnetic quantum critical metal in $3-ε$ space dimensions by extending the earlier one-loop analysis [Sur and Lee, Phys. Rev. B 91, 125136 (2015)] to higher-loop orders. We show that the $ε$-expansion is not organized by the standard loop expansion, and a two-loop graph becomes as important as one-loop graphs due to an infrared singularity caused by an emergent quasilocality. This qualitatively changes the nature of the infrared (IR) fixed point, and the $ε$-expansion is controlled only after the two-loop effect is taken into account. Furthermore, we show that a ratio between velocities emerges as a small parameter, which suppresses a large class of diagrams. We show that the critical exponents do not receive corrections beyond the linear order in $ε$ in the limit that the ratio of velocities vanishes. The $ε$-expansion gives critical exponents which are consistent with the exact solution obtained in $0 < ε\leq 1$.
description: 20 pages, 8 figures; ver2: minor corrections, comparison to ferromagnetic quantum criticality added, typos fixed, references added
A lower bound on the differential entropy of log-concave random vectors with applications
Creators: name: Marsiglietti, Arnaud
name: Kostina, Victoria
Publisher: name: arXiv
Year: 2017
Subjects: subject: Information Theory (cs.IT)
subject: FOS: Computer and information sciences
subject: 94A17

description: We derive a lower bound on the differential entropy of a log-concave random variable $X$ in terms of the $p$-th absolute moment of $X$. The new bound leads to a reverse entropy power inequality with an explicit constant, and to new bounds on the rate-distortion function and the channel capacity. Specifically, we study the rate-distortion function for log-concave sources and distortion measure $| x - \hat x|^r$, and we establish that the difference between the rate distortion function and the Shannon lower bound is at most $\log(\sqrt{πe}) \approx 1.5$ bits, independently of $r$ and the target distortion $d$. For mean-square error distortion, the difference is at most $\log (\sqrt{\frac{πe}{2}}) \approx 1$ bits, regardless of $d$. We also provide bounds on the capacity of memoryless additive noise channels when the noise is log-concave. We show that the difference between the capacity of such channels and the capacity of the Gaussian channel with the same noise power is at most $\log (\sqrt{\frac{πe}{2}}) \approx 1$ bits. Our results generalize to the case of vector $X$ with possibly dependent coordinates, and to $γ$-concave random variables. Our proof technique leverages tools from convex geometry.
description: 31 pages, 2 figures
Connecting Different TMD Factorization Formalisms in QCD
Creators: name: Collins, John
name: Rogers, Ted C.
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: In the original Collins-Soper-Sterman (CSS) presentation of the results of transverse-momentum-dependent (TMD) factorization for the Drell-Yan process, results for perturbative coefficients can be obtained from calculations for collinear factorization. Here we show how to use these results, plus known results for the quark form factor, to obtain coefficients for TMD factorization in more recent formulations, e.g., that due to Collins, and apply them to known results at order $α_s^2$ and $α_s^3$. We also show that the "non-perturbative" functions as obtained from fits to data are equal in the two schemes. We compile the higher-order perturbative inputs needed for the updated CSS scheme by appealing to results obtained in a variety of different formalisms. In addition, we derive the connection between both versions of the CSS formalism and several formalisms based in soft-collinear effective theory (SCET). Our work uses some important new results for factorization for the quark form factor, which we derive.
description: 30 pages, 2 Figures; Fixed typos including missing term in Eq.(60)
Bulletin of Online Emendations to Papyri (BOEP) 10 (November 2, 2022)
Creators: name: Ast, Rodney
name: Berkes, Lajos
name: Cowey, James M.S.
name: Essler, Holger
name: Lougovaya, Julia
Publisher: name: Pylon: Editions and Studies of Ancient Texts
Year: 2022

description: Pylon: Editions and Studies of Ancient Texts, Vol. 2 (2022)
Why there is no Newtonian backreaction
Creators: name: Kaiser, Nick
Publisher: name: arXiv
Year: 2017
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: In the conventional framework for cosmological dynamics the scale factor $a(t)$ is assumed to obey the `background' Friedmann equation for a perfectly homogeneous universe while particles move according to equations of motions driven by the gravity of the density fluctuations. It has recently been suggested that the emergence of structure modifies the evolution of $a(t)$ via Newtonian (or `kinematic') backreaction and that this may avoid the need for dark energy. Here we point out that the conventional system of equations is exact in Newtonian gravity and there is no approximation in the use of the homogeneous universe equation for $a(t)$. The recently proposed modification of Racz et al.\ (2017) does not reduce to Newtonian gravity in the limit of low velocities. We discuss the relation of this to the `generalised Friedmann equation' of Buchert and Ehlers. These are quite different things; their formula describes individual regions and is obtained under the restrictive assumption that the matter behaves like a pressure-free fluid whereas our result is exact for collisionless dynamics and is an auxiliary relation appearing in the structure equations. We use the symmetry of the general velocity autocorrelation function to show how Buchert's $\cal Q$ tends very rapidly to zero for large volume and that this does not simply arise `by construction' through the adoption of periodic boundary conditions as has been claimed. We conclude that, to the extent that Newtonian gravity accurately describes the low-$z$ universe, there is no backreaction of structure on $a(t)$ and that the need for dark energy cannot be avoided in this way.
description: 6 pages, 0 figures. Substantially revised in response to reviewer's suggestions
Valley-polarized magnetoconductivity and particle-hole symmetry breaking in a periodically modulated $α$-$\mathcal{T}_3$ lattice
Creators: name: Islam, SK Firoz
name: Dutta, Paramita
Publisher: name: arXiv
Year: 2017
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: We explore the transport properties of a periodically modulated $α$-$\mathcal{T}_3$ lattice in the presence of a perpendicular magnetic field. The effect of the Berry phase on electrical conductivity oscillation, so-called Weiss oscillation, caused by the modulation induced non-zero drift velocity of charge carriers is investigated. Employing linear response theory within the low temperature regime, we analyze Weiss oscillation as a function of the external magnetic field for both electrically and magnetically modulated $α$-$\mathcal{T}_3$ lattice numerically as well as analytically. The Berry phase makes this hexagonal lattice structure behave differently than other two-dimensional fermionic systems. It causes a significant valley polarization in magnetoconductivity. Most interestingly, the combined effect of both modulations breaks the particle-hole symmetry and causes a smooth transition from even (odd) to odd (even) filling fraction corresponding to the density of states peaks by means of the Berry phase.
description: Published version, Phys. Rev. B (2017)
Codes for Simultaneous Transmission of Quantum and Classical Information
Creators: name: Grassl, Markus
name: Lu, Sirui
name: Zeng, Bei
Publisher: name: arXiv
Year: 2017
Subjects: subject: Quantum Physics (quant-ph)
subject: Information Theory (cs.IT)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: We consider the characterization as well as the construction of quantum codes that allow to transmit both quantum and classical information, which we refer to as `hybrid codes'. We construct hybrid codes $[\![n,k{: }m,d]\!]_q$ with length $n$ and distance $d$, that simultaneously transmit $k$ qudits and $m$ symbols from a classical alphabet of size $q$. Many good codes such as $[\![7,1{: }1,3]\!]_2$, $[\![9,2{: }2,3]\!]_2$, $[\![10,3{: }2,3]\!]_2$, $[\![11,4{: }2,3]\!]_2$, $[\![11,1{: }2,4]\!]_2$, $[\![13,1{: }4,4]\!]_2$, $[\![13,1{: }1,5]\!]_2$, $[\![14,1{: }2,5]\!]_2$, $[\![15,1{: }3,5]\!]_2$, $[\![19,9{: }1,4]\!]_2$, $[\![20,9{: }2,4]\!]_2$, $[\![21,9{: }3,4]\!]_2$, $[\![22,9{: }4,4]\!]_2$ have been found. All these codes have better parameters than hybrid codes obtained from the best known stabilizer quantum codes.
description: 6 pages
KFAS: Exponential Family State Space Models in R
Creators: name: Helske, Jouni
Publisher: name: arXiv
Year: 2016
Subjects: subject: Computation (stat.CO)
subject: Methodology (stat.ME)
subject: FOS: Computer and information sciences

description: State space modelling is an efficient and flexible method for statistical inference of a broad class of time series and other data. This paper describes an R package KFAS for state space modelling with the observations from an exponential family, namely Gaussian, Poisson, binomial, negative binomial and gamma distributions. After introducing the basic theory behind Gaussian and non-Gaussian state space models, an illustrative example of Poisson time series forecasting is provided. Finally, a comparison to alternative R packages suitable for non-Gaussian time series modelling is presented.
description: 39 pages, 7 figures. This is a preprint version of an article to appear in the Journal of Statistical Software. Change to previous version: Added grant number to acknowledgments
Towards effective asset management improving operation and maintenance of a water distribution system through better information management practices: cases of Abuja, Nigeria and Kampala, Uganda
Creators: name: Enang, Roses
Publisher: name: Loughborough University
Year: 2021
Subjects: Other built environment and design not elsewhere classified

description: Both information management (IM) and operation and maintenance (O&M) are key aspects of asset management (AM) which is crucial for optimising and sustaining utility infrastructures and services. This research used an inductive approach to assess how these three subjects interacted with the aim of developing a strategy for improving operation and maintenance through better information management practices. A key focus was placed on the water distribution system (WDS), and its assets because this section made up most of the physical assets in water utilities and is the direct link to the customers. Literature showed that there was little research with detailed emphasis on IM for O&M within unreformed utilities, with a view to incremental improvements. Other research focused on systems, top management and customer perceptions while this research focused on everyday operational decisions that system operatives took to keep the system running. From the key data collection tools, a total of 67 Interviews, 55 observations and 10 document reviews were conducted. Two utilities were used as case studies: a major case from the Federal Capital Territory Water Board (FCTWB) in Nigeria and a minor case from Kampala Water (KW) in Uganda. Both utilities carried out similar O&M activities. FCTWB, having centralised its operations, often took longer to conduct O&M, with longer decision pathways and wider communication chains than KW which was decentralised and kept daily operational level O&M decisions within its branch offices. The Ugandan KW case had more resources and autonomy as compared to the Nigerian FCTWB but FCTWB showed resilience in the way it continued to manage water infrastructures despite these limitations. The nature of information and asset management between the two utilities were compared and this showed that these two utilities did successfully run water supply services to their mandated areas but FCTWB accomplished this less efficiently. Lessons from KW and the literature showed that FCTWB has the potential to achieve better asset management within the current operating environment by capitalising on its existing IM and O&M practices without making major changes to the organisational structure because asset management is best improved in an incremental way while sufficient IT and other resources become available.
Log-gamma directed polymer with one free end via coordinate Bethe Ansatz
Creators: name: Grange, Pascal
Publisher: name: arXiv
Year: 2017
Subjects: subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: The discrete polymer model with random Boltzmann weights with homogeneous inverse gamma distribution, introduced by Seppäläinen, is studied in the case of a polymer with one fixed and one free end. The model with two fixed ends has been integrated by Thiery and Le Doussal, using coordinate Bethe Ansatz techniques and an analytic-continuation prescription. The probability distribution of the free energy has been obtained through the replica method, even though the moments of the partition sum do not exist at all orders due to the fat tail in the distribution of Boltzmann weights. To extend this approach to the polymer with one free end, we argue that the contribution to the partition sums in the thermodynamic limit is localised on parity-invariant string states. This situation is analogous to the case of the continuum polymer with one free end, related to the Kardar--Parisi--Zhang equation with flat boundary conditions and solved by Le Doussal and Calabrese. The expansion of the generating function of the partition sum in terms of numbers of strings can also be transposed to the log-gamma polymer model, with the induced Fredholm determinant structure. We derive the large-time limit of the rescaled cumulative distribution function, and relate it to the GOE Tracy--Widom distribution. The derivation is conjectural in the sense that it assumes completeness of a family of string states (and expressions of their norms already used in the fixed-end problem) and extends heuristically the order of moments of the partition sum to the complex plane.
description: 29 pages, no figures; v2: 36 pages, 4 figures, section 7 added (numerical simulations), version accepted in JSTAT
The Memory Effect for Particle Scattering in Even Spacetime Dimensions
Creators: name: Garfinkle, David
name: Hollands, Stefan
name: Ishibashi, Akihiro
name: Tolish, Alexander
name: Wald, Robert M.
Publisher: name: arXiv
Year: 2017
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We explicitly calculate the gravitational wave memory effect for classical point particle sources in linearized gravity off of an even dimensional Minkowski background. We show that there is no memory effect in $d>4$ dimensions, in agreement with the general analysis of Hollands, Ishibashi, and Wald (2016).
description: 14 pages. Typos corrected, reference added, eq. (11) corrected and clarified (results unchanged), arguments in secs. IV,V revised (results unchanged)
Triggering the formation of direct collapse black holes by their congeners
Creators: name: Yue, Bin
name: Ferrara, Andrea
name: Pacucci, Fabio
name: Omukai, Kuzuyuki
Publisher: name: arXiv
Year: 2016
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Direct collapse black holes (DCBHs) are excellent candidates as seeds of supermassive black holes (SMBHs) observed at $z \gsim 6$. The formation of a DCBH requires a strong external radiation field to suppress $\rm H_2$ formation and cooling in a collapsing gas cloud. Such strong field is not easily achieved by first stars or normal star-forming galaxies. Here we investigate a scenario in which the previously-formed DCBH can provide the necessary radiation field for the formation of additional ones. Using one-zone model and the simulated DCBH Spectral Energy Distributions (SEDs) filtered through absorbing gas initially having column density $N_{\rm H}$, we derive the critical field intensity, $J_{\rm LW}^{\rm crit}$, to suppress $\rm H_2$ formation and cooling. For the SED model with $N_{\rm H}=1.3\times10^{25}$ cm$^{-2}$, $8.0\times10^{24}$ cm$^{-2}$ and $5.0\times10^{24}$ cm$^{-2}$, we obtain $J_{\rm LW}^{\rm crit}\approx22$, 35 and 54, all much smaller than the critical field intensity for normal star-forming galaxies ($J_{\rm LW}^{\rm crit}\simgt 1000$). X-ray photons from previously-formed DCBHs build up a high-$z$ X-ray background (XRB) that may boost the $J_{\rm LW}^{\rm crit}$. However, we find that in the three SED models $J_{\rm LW}^{\rm crit}$ only increases to $\approx80$, 170 and 390 respectively even when $\dtρ_\bullet$ reaches the maximum value allowed by the present-day XRB level ($0.22, 0.034, 0.006~M_\odot$yr$^{-1}$Mpc$^{-3}$), still much smaller than the galactic value. Although considering the XRB from first galaxies may further increase $J_{\rm LW}^{\rm crit}$, we conclude that our investigation supports a scenario in which DCBH may be more abundant than predicted by models only including galaxies as external radiation sources.
description: 18 pages, 14 figures, 5 tables, ApJ in press
Nonlinear dust-acoustic solitary waves and shocks in dusty plasmas with a pair of trapped ions
Creators: name: Adhikary, N. C.
name: Misra, A. P.
name: Deka, M. K.
name: Dev, A. N.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Plasma Physics (physics.plasm-ph)
subject: FOS: Physical sciences

description: The propagation characteristics of small-amplitude dust-acoustic (DA) solitary waves (SWs) and shocks are studied in an unmagnetized dusty plasma with a pair of trapped positive and negative ions. Using the standard reductive perturbation technique with two different scaling of stretched coordinates, the evolution equations for DA SWs and shocks are derived in the forms of complex Korteweg-de Vries (KdV) and complex Burgers' equations. The effects of dust charge variation, the dust thermal pressure, and the ratios of positive to negative ion number densities as well as the free to trapped ion temperatures on the profiles of SWs and shocks are analysed and discussed.
description: 23 pages, 10 figures
Measurement of charged-particle distributions sensitive to the underlying event in $\sqrt{s} = 13$ TeV proton-proton collisions with the ATLAS detector at the LHC
Creators: name: ATLAS Collaboration
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: We present charged-particle distributions sensitive to the underlying event, measured by the ATLAS detector in proton-proton collisions at a centre-of-mass energy of 13 TeV, in low-luminosity Large Hadron Collider fills corresponding to an integrated luminosity of 1.6 nb$^{-1}$. The distributions were constructed using charged particles with absolute pseudorapidity less than 2.5 and with transverse momentum greater than 500 MeV, in events with at least one such charged particle with transverse momentum above 1 GeV. These distributions characterise the angular distribution of energy and particle flows with respect to the charged particle with highest transverse momentum, as a function of both that momentum and of charged-particle multiplicity. The results have been corrected for detector effects and are compared to the predictions of various Monte Carlo event generators, experimentally establishing the level of underlying-event activity at LHC Run 2 energies and providing inputs for the development of event generator modelling. The current models in use for UE modelling typically describe this data to 5% accuracy, compared with data uncertainties of less than 1%.
description: 40 pages in total, author list starting page 24, 7 figures, 3 tables, accepted for publication by JHEP, All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2016-07/
The Human Machine
Creators: name: Hendry, Manuel Flurin
Publisher: name: Zenodo
Year: 2022
Subjects: Affective Computing
Artificial Intelligence
Acting
History of Science
STS

description: The video recording of this presentation is available for streaming at vimeo.com/825059994

 Here, we investigate the split-screen history of emotional research in the art of acting and in scientific psychology. By exploring the genealogy and visual aesthetics of atlantes of emotion, we hypothesize that the lack of communication between practitioners of art and science is an obstacle to progress in affective computing, and that important scientific lessons can be learned from the history of art. To that end, we will present «Stanley», an emotion-enabled virtual human in conversation with stage actors.
Lessons for Protected Area Management in Vietnam: Outcomes of Local Ethnic Minority Participation in Forest Protection of Cat Tien National Park
Creators: name: Duong, Thi Minh Phuong
name: de Bruyn, Lisa Lobry
name: Kristiansen, Paul
name: Marshall, Graham R.
name: Wilkes, Janelle
Publisher: name: Taylor & Francis
Year: 2023
Subjects: subject: Medicine
subject: Ecology
subject: FOS: Biological sciences
subject: Science Policy

description: While protected areas are a measure for forest conservation, they pose a number of key challenges to local people’s livelihoods. One solution to the tension between conservation objectives and livelihoods in protected areas is involving local people in forest protection activities. The research examined the performance of one initiative, involving Forest Protection Teams (FPTs), on the livelihoods of local people and participating members, and on forest conservation. The research revealed that FPT activities had some benefits for team members but limited impact on local livelihoods. Additionally, most households stated that there was no detectable change in forest condition because of team members’ activities in forest protection. For FPT members to take greater ownership of forest protection outcomes and communication of these outcomes, the program needs to be designed and implemented in a more participatory manner.
Nonlinear QED effects in X-ray emission of pulsars
Creators: name: Shakeri, Soroush
name: Haghighat, Mansour
name: Xue, She-Sheng
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: In the presence of strong magnetic fields near pulsars, the QED vacuum becomes a birefringent medium due to nonlinear QED interactions. Here, we explore the impact of the effective photon-photon interaction on the polarization evolution of photons propagating through the magnetized QED vacuum of a pulsar. We solve the quantum Boltzmann equation within the framework of the Euler-Heisenberg Lagrangian to find the evolution of the Stokes parameters. We find that linearly polarized X-ray photons propagating outward in the magnetosphere of a rotating neutron star can acquire high values for the circular polarization parameter. Meanwhile, it is shown that the polarization characteristics of photons besides photon energy depend strongly on parameters of the pulsars such as magnetic field strength, inclination angle and rotational period. Our results are clear predictions of QED vacuum polarization effects in the near vicinity of magnetic stars which can be tested with the upcoming X-ray polarimetric observations.
description: 12 pages, 3 figures
“Collaborative NGO Analysis in NRM: When your collaborator is also your unit of analysis”
Creators: name: Erwin, Anna
name: MacAuley, Lorien
name: McWherter, Brooke
Publisher: name: Taylor & Francis
Year: 2023
Subjects: subject: Microbiology
subject: FOS: Biological sciences
subject: Biotechnology
subject: Ecology
subject: Sociology
subject: FOS: Sociology
subject: 69999 Biological Sciences not elsewhere classified
subject: Cancer
subject: Science Policy

description: NGOs (Non-Governmental Organizations) continue to take more responsibility in Natural Resource Management (NRM). This requires in-depth analyses of the roles NGOs play in NRM. Collaborative NGO Analysis (CNGOA), whereby scholars take an expert role and partner with an NGO to study the organization, its impacts/activities, and its partnerships, can provide new insight into NGO roles in NRM. Existing collaborative studies in NRM primarily apply participatory and community-based approaches whereby researchers partner with organizations to study a problem, such as climate change. However, few studies use CNGOA. This research note addresses this gap by presenting three cases that use CNGOA. CNGOA can create new opportunities to apply theoretical constructs and open spaces for NGO reflexivity. Flexible agreements that include conditions for NGO involvement and anonymity support the approach and can protect the NGO and address some equity concerns. Findings lay the groundwork for additional studies that apply CNGOA in NRM.
Properties and impact of AGN outflows from low to high-z
Creators: name: Cresci Giovanni
Publisher: name: Zenodo
Year: 2022

description: In this contribution, I will review the main observational findings about AGN-driven outflows and their impact on their host galaxies, both in the local and high-z universe. I will describe the multi-phase nature of this phenomenon, the different tools and wavelengths used to study them, and the evidence available about an impact of these outflows on their host galaxies ISM.
Nonlocal birth-death competitive dynamics with volume exclusion
Creators: name: Khalil, Nagi
name: López, Cristóbal
name: Hernández-García, Emilio
Publisher: name: arXiv
Year: 2017
Subjects: subject: Biological Physics (physics.bio-ph)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: A stochastic birth-death competition model for particles with excluded volume is proposed. The particles move, reproduce, and die on a regular lattice. While the death rate is constant, the birth rate is spatially nonlocal and implements inter-particle competition by a dependence on the number of particles within a finite distance. The finite volume of particles is accounted for by fixing an upper value to the number of particles that can occupy a lattice node, compromising births and movements. We derive closed macroscopic equations for the density of particles and spatial correlation at two adjacent sites. Under different conditions, the description is further reduced to a single equation for the particle density that contains three terms: diffusion, a linear death, and a highly nonlinear and nonlocal birth term. Steady-state homogeneous solutions, their stability which reveals spatial pattern formation, and the dynamics of time-dependent homogeneous solutions are discussed and compared, in the one-dimensional case, with numerical simulations of the particle system.
description: 21 pages
Connecting the shadows: probing inner disk geometries using shadows in transitional disks
Creators: name: Min, M.
name: Stolker, T.
name: Dominik, C.
name: Benisty, M.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: Shadows in transitional disks are generally interpreted as signs of a misaligned inner disk. This disk is usually beyond the reach of current day high contrast imaging facilities. However, the location and morphology of the shadow features allow us to reconstruct the inner disk geometry. We derive analytic equations of the locations of the shadow features as a function of the orientation of the inner and outer disk and the height of the outer disk wall. In contrast to previous claims in the literature, we show that the position angle of the line connecting the shadows cannot be directly related to the position angle of the inner disk. We show how the analytic framework derived here can be applied to transitional disks with shadow features. We use estimates of the outer disk height to put constraints on the inner disk orientation. In contrast with the results from Long et al. (2017), we derive that for the disk surrounding HD100453 the analytic estimates and interferometric observations result in a consistent picture of the orientation of the inner disk. The elegant consistency in our analytic framework between observation and theory strongly support both the interpretation of the shadow features as coming from a misaligned inner disk as well as the diagnostic value of near infrared interferometry for inner disk geometry.
description: Accepted in A&A Letters
Epoch of Reionisation 21cm Forecasting From MCMC-Constrained Semi-Numerical Models
Creators: name: Hassan, Sultan
name: Dave, Romeel
name: Finlator, Kristian
name: Santos, Mario G.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: The recent low value of Planck (2016) integrated optical depth to Thomson scattering suggests that the reionization occurred fairly suddenly, disfavoring extended reionization scenarios. This will have a significant impact on the 21cm power spectrum. Using a semi-numerical framework, we improve our model from Hassan et al. (2016) to include time-integrated ionisation and recombination effects, and find that this leads to more sudden reionisation. It also yields larger HII bubbles which leads to an order of magnitude more 21cm power on large scales, while suppressing the small scale ionization power. Local fluctuations in the neutral hydrogen density play the dominant role in boosting the 21cm power spectrum on large scales, while recombinations are subdominant. We use a Monte Carlo Markov Chain approach to constrain our model to observations of the star formation rate functions at z = 6,7,8 from Bouwens et al. (2015), the Planck (2016) optical depth measurements, and the Becker & Bolton (2013) ionising emissivity data at z~5. We then use this constrained model to perform 21cm forecasting for LOFAR, HERA, and SKA in order to determine how well such data can characterise the sources driving reionisation. We find that the 21cm power spectrum alone can somewhat constrain the halo mass dependence of ionising sources, the photon escape fraction and ionising amplitude, but combining the 21cm data with other current observations enables us to separately constrain all these parameters. Our framework illustrates how 21cm data can play a key role in understanding the sources and topology of reionisation as observations improve.
description: 20 pages, 16 figues, matches the accepted version for publication in MNRAS
The chemistry of episodic accretion in embedded objects. 2D radiation thermo-chemical models of the post-burst phase
Creators: name: Rab, Ch.
name: Elbakyan, V.
name: Vorobyov, E.
name: Güdel, M.
name: Dionatos, O.
name: Audard, M.
name: Kamp, I.
name: Thi, W. -F.
name: Woitke, P.
name: Postel, A.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Episodic accretion is an important process in the evolution of young stars and their environment. The observed strong luminosity bursts of young stellar objects likely have a long lasting impact on the chemical evolution of the disk and envelope structure. We want to investigate observational signatures of the chemical evolution in the post-burst phase for embedded sources. With such signatures it is possible to identify targets that experienced a recent luminosity burst. We present a new model for episodic accretion chemistry based on the 2D, radiation thermo-chemical disk code ProDiMo. We have extended ProDiMo with a proper treatment for envelope structures. For a representative Class I model, we calculated the chemical abundances in the post-burst phase and produced synthetic observables like intensity maps and radial profiles. During a burst many chemical species, like CO, sublimate from the dust surfaces. As the burst ends they freeze out again (post-burst phase). This freeze-out happens from inside-out due to the radial density gradient in the disk and envelope structure. This inside-out freeze-out produces clear observational signatures in spectral line emission, like rings and distinct features in the slope of radial intensity profiles. We fitted synthetic C18O J=2-1 observations with single and two component fits and find that post-burst images are much better matched by the latter. Comparing the quality of such fits allows identification of post-burst targets in a model-independent way. Our models confirm that it is possible to identify post-burst objects from spatially resolved CO observations. However, to derive proper statistics, like frequencies of bursts, from observations it is important to consider aspects like the inclination and structure of the target and also dust properties as those have a significant impact on the freeze-out timescale.
description: 17 pages, 6 figures, 2 tables. Accepted for publication in A&A
title: Nanostructured Ti-13Nb-13Zr alloy for implant application — material scientific, technological, and biological aspects
Creators: name: Klinge, Lina
name: Kluy, Lukas
name: Spiegel, Christopher
name: Siemers, Carsten
name: Groche, Peter
name: Coraça-Huber, Débora
Publisher: name: Frontiers Media S.A.
Year: 2023

description: In dentistry, the most commonly used implant materials are CP-Titanium Grade 4 and Ti-6Al-4V ELI, possessing comparably high Young’s modulus (>100 GPa). In the present study, the second-generation titanium alloy Ti-13Nb-13Zr is investigated with respect to the production of advanced dental implant systems. This should be achieved by the fabrication of long semi-finished bars with high strength and sufficient ductility to allow the automated production of small implants at low Young’s modulus (<80 GPa) to minimize stress shielding, bone resorption, and gap formation between the bone and implant. In addition, bacterial colonization is to be reduced, and bone adhesion is to be enhanced by adjusting the microstructure. To do so, a dedicated thermo-mechanical treatment for Ti-13Nb-13Zr has been developed. This includes the adaption of equal channel angular swaging, a modern process of severe plastic deformation to continuously manufacture nanostructured materials, to Ti-13Nb-13Zr and short-time recrystallization and ageing treatments. In particular, two-pass equal channel angular swaging at a deformation temperature of 150°C and a counterpressure of 8 MPa has successfully been used to avoid shear band formation during deformation and to produce long Ti-13Nb-13Zr bars of 8 mm diameter. During recrystallization treatment at 700°C for 10 min followed by water quenching, a sub-micron-size primary α-phase in a matrix of α″-phase was developed. Subsequent ageing at 500°C for 1 h leads to martensite decomposition and, thus, to a homogeneously nanostructured microstructure of α- and β-phase with substructures smaller than 200 nm. The resulting mechanical properties, especially the ultimate tensile strength of more than 990 MPa, fulfill the requirements of ASTM F1713 at Young’s modulus of 73 GPa. Biological investigations show promising results in reducing bacterial biofilm formation and increased cell proliferation of osteoblasts compared to CP-Titanium Grade 4 and Ti-6Al-4V ELI, especially, if etched surfaces are applied.
Robust Sequential Change-Point Detection by Convex Optimization
Creators: name: Cao, Yang
name: Xie, Yao
Publisher: name: arXiv
Year: 2017
Subjects: subject: Methodology (stat.ME)
subject: FOS: Computer and information sciences

description: We address the computational challenge of finding the robust sequential change-point detection procedures when the pre- and post-change distributions are not completely specified. Earlier works [veeravalli 1994] and [Unnikrishnan 2011] establish the general conditions for robust procedures which include finding a pair of least favorable distributions (LFDs). However, in the multi-dimensional setting, it is hard to find such LFDs computationally. We present a method based on convex optimization that addresses this issue when the distributions are Gaussian with unknown parameters from pre-specified uncertainty sets. We also establish theoretical properties of our robust procedures, and numerical examples demonstrate their good performance.
description: Accepted by ISIT 2017
title: Modeling institutional research data repositories using the DCAT3 Data Catalog Vocabulary
title: A case study on TUdatalib
titleType: Subtitle
Creators: name: Geißner, Andreas
Publisher: name: Humboldt-Universität zu Berlin
Year: 2023
Subjects: subject: DCAT
subject: DSpace
subject: 020 Bibliotheks- und Informationswissenschaften

description: Semantic Web and Linked Data technologies might solve issues originating from research data being published by independent providers. For maximum benefit from these technologies, metadata should be provided as standardized as possible. The Data Catalog Vocabulary (DCAT) is a W3C recommendation of potential value for Linked Data exposure of research data metadata. The suitability of DCAT for institutional research data repositories was investigated using the TUdatalib repository as study case. A model for TUdatalib metadata was developed based on the analysis of selected resources and guided by a draft of DCAT 3. The model allowed for providing the essential information about the repository structure and contents indicating suitability of the vocabulary and, conceptually, should permit automated data conversion from the repository system to DCAT 3. A loss of expressiveness comes from the omission of dataset series. Conformance with DCAT 3 class definitions led to a highly complex model, thus creating challenges with actual technical realizations. A comparative study revealed simpler models to be used at two other repositories, but implementation of the TUdatalib or a similar model would have potential to improve alignment to DCAT specifications. DCAT 3 was observed to be a promising option for Linked Data exposure of institutional research data repository metadata and the TUdatalib model might serve towards developing a general DCAT 3 application profile for institutional and other research data repositories.
Poultry Expected To Continue Leading Global Meat Imports as Demand Rises
Creators: name: Miller, Matthew
name: Gerval, Adam
name: Hansen, James
name: Grossen, Grace
name: Miller, Matthew
name: Gerval, Adam
name: Hansen, James
name: Grossen, Grace
Publisher: name: Unknown
Year: 2022
Subjects: Agribusiness
Agricultural and Food Policy
Consumer/Household Economics
Demand and Price Analysis
Farm Management
Financial Economics
Food Consumption/Nutrition/Food Safety
Land Economics/Use
Livestock Production/Industries

description: Over the past two decades, poultry has become the most consumed livestock commodity in the world, especially in developing and emerging markets where production prospects have been relatively limited. As demand for poultry products grew in these markets during the period from 2001 to 2021, global imports increased. Poultry is expected to remain the world’s largest imported livestock commodity by volume over the next 10 years. To meet rising demand, a number of countries increased domestic poultry production. Brazil, the United States, the European Union, and Thailand emerged as major poultry exporters. Brazil is the world’s leading poultry exporter and is projected to remain in the top position through 2031. The United States, however, is expected to lose market share throughout the coming decade.
Rigidity of isometric immersions into the light cone
Creators: name: Liu, Jian-Liang
name: Yu, Chengjie
Publisher: name: arXiv
Year: 2017
Subjects: subject: Differential Geometry (math.DG)
subject: FOS: Mathematics

description: In this paper, we show the rigidity of isometric immersions for a Riemannian manifold of dimension $n-1$ into the light cone of $n+1$ dimensional Minkowski, de Sitter and anti-de Sitter spacetimes for $n\geq 3$.
description: Fix a mistake. All comments are welcome
title: Front Matter, Table of Contents, Preface, Conference Organization
Creators: name: Becker, Matthias
name: Forget, Julien
Publisher: name: Schloss Dagstuhl - Leibniz-Zentrum für Informatik
Year: 2023
Subjects: subject: Front Matter
subject: Table of Contents
subject: Preface
subject: Conference Organization
subject: Software and its engineering

description: Front Matter, Table of Contents, Preface, Conference Organization
description: DARTS, Vol. 9, Special Issue of the 35th Euromicro Conference on Real-Time Systems (ECRTS 2023), pages 0:i-0:x
title: A New Perspective on Criticality: Efficient State Abstraction and Run-Time Monitoring of Mixed-Criticality Real-Time Control Systems (Artifact)
Creators: name: Rheinfels, Tim
name: Gaukler, Maximilian
name: Ulbrich, Peter
Publisher: name: Schloss Dagstuhl - Leibniz-Zentrum für Informatik
Year: 2023
Subjects: subject: Real-time Control
subject: Mixed-Criticality
subject: Switched Systems
subject: State Monitoring
subject: Computer systems organization → Real-time systems
subject: Computer systems organization → Embedded and cyber-physical systems
subject: Computer systems organization → Dependable and fault-tolerant systems and networks

description: The increasing complexity of real-time control systems, comprising control tasks interacting with physics and non-control tasks, comes with substantial challenges: meeting various non-functional requirements implies conflicting design goals and a pronounced gap between worst and average-case resource requirements up to the overall timeliness being unverifiable. Mixed-criticality systems (MCS) are a well-known mitigation concept that operate the system in different criticality levels with timing guarantees given only to the subset of critical tasks. In many real-world applications, the criticality of control applications is tied to the system’s physical state and control deviation, with safety specifications becoming a crucial design objective. Monitoring the physical state and adapting scheduling is inaccessible to MCS but has been dedicated mainly to control engineering approaches such as self-triggered (model-predictive) control. These, however, are hard to schedule or expensive at run time.
This paper explores the potential of linking both worlds and elevating the physical state to a criticality criterion. We, therefore, propose a dedicated state estimation that can be leveraged as a run-time monitor for criticality mode changes. For this purpose, we develop a highly efficient one-dimensional state abstraction to be computed within the operating system’s scheduling. Furthermore, we show how to limit abstraction pessimism by feeding back state measurements robustly. The paper focuses on the control fundamentals and outlines how to leverage this new tool in adaptive scheduling. Our experimental results substantiate the efficiency and applicability of our approach.
description: DARTS, Vol. 9, Special Issue of the 35th Euromicro Conference on Real-Time Systems (ECRTS 2023), pages 1:1-1:3