cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Friends and Foes: Conditional Occurrence Rates of Exoplanet Companions and their Impact on Radial Velocity Follow-up Surveys
Creators: name: He, Matthias Y.
name: Ford, Eric B.
name: Ragozzine, Darin
Publisher: name: arXiv
Year: 2021
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: Population studies of Kepler's multi-planet systems have revealed a surprising degree of structure in their underlying architectures. Information from a detected transiting planet can be combined with a population model to make predictions about the presence and properties of additional planets in the system. Using a statistical model for the distribution of planetary systems (He et al. 2020; arXiv:2007.14473), we compute the conditional occurrence of planets as a function of the period and radius of Kepler-detectable planets. About half ($0.52 \pm 0.03$) of the time, the detected planet is not the planet with the largest semi-amplitude $K$ in the system, so efforts to measure the mass of the transiting planet with radial velocity (RV) follow-up will have to contend with additional planetary signals in the data. We simulate RV observations to show that assuming a single-planet model to measure the $K$ of the transiting planet often requires significantly more observations than in the ideal case with no additional planets, due to the systematic errors from unseen planet companions. Our results show that planets around 10-day periods with $K$ close to the single-measurement RV precision ($σ_{1,\rm obs}$) typically require $\sim 100$ observations to measure their $K$ to within 20% error. For a next generation RV instrument achieving $σ_{1,\rm obs} = 10$ cm/s, about $\sim 200$ ($600$) observations are needed to measure the $K$ of a transiting Venus in a Kepler-like system to better than 20% (10%) error, which is $\sim 2.3$ times as many as what would be necessary for a Venus without any planetary companions.
description: Accepted to AJ. 28 pages, 13 figures
Novel waveguides for terahertz quantum cascade lasers
Creators: name: Klimont, Adam
Publisher: name: Apollo - University of Cambridge Repository
Year: 2019
Subjects: terahertz
quantum cascade laser
photonic crystal
waveguides
semiconductors

description: Since their first demonstration in 2002, terahertz (THz) quantum cascade lasers (QCLs) have proven to be one of the most reliable sources of this type of radiation. Advances have been made in increasing maximum operating temperature, shaping the beam and tuning the frequency and bandwidth. Waveguide engineering has been a particular area of interest due to the large wavelength of the THz radiation (> 100 μm). This thesis introduces several improvements related to THz QCL waveguide technology. We begin by describing the THz radiation range, its applications and available sources. We then focus on the theoretical framework used to describe and design QCLs. We also review the two main waveguides employed in THz QCLs: the surface plasmon (SP) and the metal-metal (MM) waveguides. We outline the main fabrication steps for both waveguides. Firstly, a novel photonic crystal-based QCL is presented. It comprises a defect line in a triangular lattice of active region (GaAs/AlGaAs) pillars embedded in a polymer matrix. The defects are made of pillars larger than the lattice pillars. Lasing is possible in this device on specific frequency levels (defect modes) within the band gap of the photonic crystal. Emitted frequency can be finely tuned by changing the size of the pillars in the lattice. A non-linear QCL geometry (a 90° junction), which allows for arbitrary emission direction, is also presented. Such waveguides may play an important role in integrated THz circuits. Secondly, a new hybrid plasmonic waveguide for THz QCL is presented. It employs a polymer, benzocyclobutene (BCB), which solidifies upon heating and acts as a bonding agent. This waveguide serves as an alternative to MM and allows for arbitrarily thick metal deposition below the active region. Simulations are presented with an aim to explain the observed beam shape. For two different active regions and different thicknesses of bottom gold layer, a full light-current-voltage, spectral, and far-field characterisation is presented. The BCB-bonded device may be another element crucial in developing integrated THz elements on chip as it is more flexible than the rigid, substrate-based MM waveguide fabrication. Thirdly, another novel concept of a THz QCL waveguide is presented, which employs etched pockets in the substrate directly below the active region. The air pockets allow for reducing the bottom plasmon layer doping and improving the ratio between the mode overlap (with the gain medium) and waveguide loss. The process development is presented, as well as simulations corroborating the hypothesis that this device has a potential to outperform surface plasmon waveguides. Finally, potential applications of this work are discussed and suggestions are made for further work that could be done to improve the presented concepts.
description: EPSRC, Schiff Fund
Ausferritic Microstructure Phase Analysis in Ductile Iron
Creators: name: Trzaskowski, W.
name: Nawrocki, P.
name: Łukasik, K.
name: Myszka, D.
Publisher: name: The Katowice Branch of the Polish Academy of Sciences
Year: 2018
Subjects: ADI
Ausferriticductile iron
Austenite
X-ray diffraction
ferrite
image analysis

description: Archives of Foundry Engineering continues the publishing activity
 started by Foundry Commission of the Polish Academy of Sciences (PAN) in
 Katowice in 1978. The initiator of it was the first Chairman Professor
 Dr Eng. Wacław Sakwa – Corresponding Member of PAN, Honorary Doctor of
 Czestochowa University of Technology and Silesian University of
 Technology. This periodical first name was „Solidification of Metals and
 Alloys” , and made possible to publish the results of works achieved in
 the field of the Basic Problems Research Cooperation. The subject of
 publications was related to the title of the periodical and concerned
 widely understand problems of metals and alloys crystallization in a
 casting mold. In 1978-2000 the 44 issues have been published. Since 2001
 the Foundry Commission has had patronage of the annually published
 “Archives of Foundry” and since 2007 quarterly published “Archives of
 Foundry Engineering”. Thematic scope includes scientific issues of
 foundry industry:

 Theoretical Aspects of Casting Processes,

 Innovative Foundry Technologies and Materials,

 Foundry Processes Computer Aiding,

 Mechanization, Automation and Robotics in Foundry,

 Transport Systems in Foundry,

 Castings Quality Management,

 Environmental Protection.
description: Image analysis allows to acquire a number of valuable quantitative informations on the observed structure and make appropriate conclusions.
So far, a large part of analyzed images came only from light microscopes, where it was a possibility of accurately distinguish the different
phases on the plane. However, the problem happened in the case of the observation of images obtained by scanning electron microscopy. In
this case, the presence of various shades of gray, and the spaciousness of the image attained. To perform the analysis the matrix images of
the ausferritic ductile iron were used. Full analysis was carried out using the computer program MicroMeter 1.03. Results obtained in the
analysis were related directly to the results from X-ray diffraction. Obtained as a result of the analysis were related directly to the results
from X-ray diffractometer.
The following technique has weaknesses, including the misinterpretation by the operator microscope or program. After all, it was possible
to obtain similar results to the result that has been obtained from X-ray diffractometer.
Navigator Function for the Conformal Bootstrap
Creators: name: Reehorst, Marten
name: Rychkov, Slava
name: Simmons-Duffin, David
name: Sirois, Benoit
name: Su, Ning
name: van Rees, Balt
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: Current numerical conformal bootstrap techniques carve out islands in theory space by repeatedly checking whether points are allowed or excluded. We propose a new method for searching theory space that replaces the binary information "allowed"/"excluded" with a continuous "navigator" function that is negative in the allowed region and positive in the excluded region. Such a navigator function allows one to efficiently explore high-dimensional parameter spaces and smoothly sail towards any islands they may contain. The specific functions we introduce have several attractive features: they are everywhere well-defined, can be computed with standard methods, and evaluation of their gradient is immediate due to an SDP gradient formula that we provide. The latter property allows for the use of efficient quasi-Newton optimization methods, which we illustrate by navigating towards the 3d Ising island.
description: 60 pages, 22 figures. v2: minor changes and fixes, added subsection 3.1 on differentiability
Significance of void shape: Neutrino mass from Voronoi void halos?
Creators: name: Bayer, Adrian E.
name: Liu, Jia
name: Kreisch, Christina D.
name: Pisani, Alice
Publisher: name: arXiv
Year: 2024
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: Massive neutrinos suppress the growth of cosmic structure on nonlinear scales, motivating the use of information beyond the power spectrum to tighten constraints on the neutrino mass, for example by considering cosmic voids. It was recently proposed that constraints on neutrino mass from the halo mass function (HMF) can be improved by considering only the halos that reside within voids -- the void-halo mass function (VHMF). We extend this analysis, which made spherical assumptions about the shape of voids, to take into account the non-spherical nature of voids as defined by the Voronoi-tessellation-based void finder, VIDE. In turn, after accounting for one spurious non-spherical void, we find no evidence that the VHMF contains information beyond the HMF. Given this finding, we then introduce a novel summary statistic by splitting halos according to the emptiness of their individual environments, defined by the Voronoi cell volume each halo resides in, and combining the mass functions from each split. We name the corresponding statistic the VorHMF and find that it could provide information regarding neutrino mass beyond the HMF. Our work thus motivates the importance of accounting for the full shape of voids in future analyses, both in terms of removing outliers to achieve robust results and as an additional source of cosmological information.
description: 8 pages, 5 figures, published as letter in PRD
Writing on Dirty Paper with Resizing and its Application to Quasi-Static Fading Broadcast Channels
Creators: name: Zhang, Wenyi
name: Kotagiri, Shivaprasad
name: Laneman, J. Nicholas
Publisher: name: arXiv
Year: 2007
Subjects: subject: Information Theory (cs.IT)
subject: FOS: Computer and information sciences

description: This paper studies a variant of the classical problem of ``writing on dirty paper'' in which the sum of the input and the interference, or dirt, is multiplied by a random variable that models resizing, known to the decoder but not to the encoder. The achievable rate of Costa's dirty paper coding (DPC) scheme is calculated and compared to the case of the decoder's also knowing the dirt. In the ergodic case, the corresponding rate loss vanishes asymptotically in the limits of both high and low signal-to-noise ratio (SNR), and is small at all finite SNR for typical distributions like Rayleigh, Rician, and Nakagami. In the quasi-static case, the DPC scheme is lossless at all SNR in terms of outage probability. Quasi-static fading broadcast channels (BC) without transmit channel state information (CSI) are investigated as an application of the robustness properties. It is shown that the DPC scheme leads to an outage achievable rate region that strictly dominates that of time division.
description: To appear in IEEE International Symposium on Information Theory 2007
How broadening social connections changes farmers’ conceptions about biodiversity.
Creators: name: Thareau, Bertille
name: Pailleux, Clara
name: Anzalone, Guilhem
name: Thareau, Bertille
name: Pailleux, Clara
name: Anzalone, Guilhem
Publisher: name: Unknown
Year: 2020
Subjects: subject: Agricultural and Food Policy
subject: Teaching/Communication/Extension/Profession
subject: Occupational conception
subject: Socio-professional path
subject: Agro-ecology
subject: Social network
subject: Professional knowledge

description: The relationship between agriculture and biodiversity divides opinion among farmers. Our research proposes to describe and interpret these opinions, with regard to the diversity of the social backgrounds of the producers, with the hypothesis that interactions with local, non-agricultural individuals help shape these opinions. From 14 interviews carried out with farmers engaged in actions to preserve biodiversity in three territories in the West of France, we identify four different occupational conceptions, characterized by knowledge and taking natural entities into account, through the values and vision of the role that farmers intend to play with regard to biodiversity and way in which they would like this issue to be handled by society. While the role of peer networks in the construction of job conceptions is well established, our research shows that understanding the attitudes of agricultural professionals today requires a consideration of the role that experience and interactions with those outside the agricultural professional sphere play.
Governing the coexistence of agricultural models: French cities allocating farmlands to support agroecology and short food chains on urban fringes
Creators: name: Perrin, Coline
name: Baysse-Lainé, Adrien
name: Perrin, Coline
name: Baysse-Lainé, Adrien
Publisher: name: Unknown
Year: 2020
Subjects: subject: Agricultural and Food Policy
subject: Community/Rural/Urban Development
subject: Access to land
subject: Agroecology
subject: Land property rights
subject: Justice
subject: Public policies
subject: Peri-urban agriculture

description: This paper deals with the coexistence of agricultural models from the perspective of land management on the urban fringe. Our goal is to show how urban local authorities deal with and influence the coexistence of models when they are involved in farmland management, and more specifically when they determine which farmer should be allocated what land and under which lease agreement. To do this, we compare public processes of farmland allocation led by French local authorities on the urban fringes of Lyon, Montpellier, and Perpignan. This geographic study is based on qualitative methods (observations, interviews, and document analysis). The comparison of seven case studies illustrates the changing balances of power on urban fringes between agricultural models and between urban and agricultural stakeholders. As urban local authorities grant them land and legitimacy, farmers willing to develop agroecology and short food supply chains may settle in peri-urban areas, where access to land is otherwise very difficult for outsiders. Some public allocations of farmland divide space between models following agronomic and esthetic criteria, but few public bodies venture to hierarchize models by an unequal repartition of land property rights. Beyond their limited spatial impact, public allocations of farmland are actually important local initiatives for the institutional recognition of sustainable agriculture models, one driver within urban policies aiming at supporting a transition towards agroecology and more sustainable food systems. Governance processes could, however, be improved if local authorities would more explicitly tackle the possible issues related to the coexistence of diverse agricultural models in space, as in public debates and policies.
Investigating 3D genome organisation in Caenorhabditis elegans with Accessible Region Conformation Capture (ARC-C)
Creators: name: Seow, Wei Qiang
Publisher: name: Apollo - University of Cambridge Repository
Year: 2019
Subjects: Hi-C
c. elegans
ARC-C
conformation-capture
genome organisation
genome architecture
regulatory elements
regulatory interactions

description: 3C and its derivatives have been applied in various organisms to study chromatin architecture. However, these methods have limitations: most of them are limited to restriction-fragment resolution and all of them, with the exception of Hi-C, only survey a pre-defined subset of the genome. I developed a variant of Hi-C, named Accessible Region Conformation Capture (ARC-C), in C. elegans, which interrogates genome organisation at multiple scales genome-wide - from domains and compartments to high resolution interactions between regulatory elements. I applied ARC-C in wild-type Bristol N2, met-2 set-25 mutants that have no H3K9 methylation to study the effects on domain and compartment formation. In these mutants, compartmentalisation (i.e. inter-domain interactions) between H3K27me3-enriched regulated domains is reduced. I also used ARC-C in blmp-1 mutants to understand the role of BLMP-1 in chromatin looping. In blmp-1 mutants, interactions between putative BLMP-1 mediated loops for downregulated genes are significantly reduced. In wild-type worms, when surveying significant interactions at 500 bp resolution, I observe the presence of dense clusters of significant interactions anchored at high occupancy target (HOT) regions that I call “hubs.” Interestingly, the deletion of these hubs does not affect the transcription of linked or local genes. However, local interactions are altered and some extent of redundancy is observed. To improve our ARC-C protocol, I tested several variations with different enzymes and biotin-mediated streptavidin beads pulldown. In all, ARC-C revealed insights into genome organisation in C. elegans and I have made progress toward a next-generation version of the method.
description: A*STAR National Science Scholarship (PhD)
Electromagnetically induced transparency in a V-system with $^{87}$Rb vapor in the hyperfine Paschen-Back regime
Creators: name: Higgins, Clare R
name: Hughes, Ifan G
Publisher: name: arXiv
Year: 2021
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: We observe EIT in a V-system in a thermal rubidium-87 vapour in the hyperfine Paschen-Back regime, realised with a 0.6 T axial magnetic field. In this regime energy levels are no longer degenerate and EIT features from different initial states are distinct, which we show produces a much cleaner feature than without a magnetic field. We compare our results to a model using the time-dependent Lindblad master equation, and having averaged over a distribution of interaction times, see good qualitative agreement for a range of pump Rabi frequencies. Excited state decay into both ground states is shown to play a prominent role in the generation of the transparency feature, which arises mainly due to transfer of population into the ground state not coupled by the probe beam. We use the model to investigate the importance of coherence in this feature, showing that its contribution is more significant at smaller pump Rabi frequencies.
description: 8 pages, 8 figures
Molecular line radiative transfer in protoplanetary disks: Monte Carlo simulations versus approximate methods
Creators: name: Pavlyuchenkov, Ya.
name: Semenov, D.
name: Henning, Th.
name: Guilloteau, St.
name: Pietu, V.
name: Launhardt, R.
name: Dutrey, A.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We analyze the line radiative transfer in protoplanetary disks using several approximate methods and a well-tested Accelerated Monte Carlo code. A low-mass flaring disk model with uniform as well as stratified molecular abundances is adopted. Radiative transfer in low and high rotational lines of CO, C18O, HCO+, DCO+, HCN, CS, and H2CO is simulated. The corresponding excitation temperatures, synthetic spectra, and channel maps are derived and compared to the results of the Monte Carlo calculations. A simple scheme that describes the conditions of the line excitation for a chosen molecular transition is elaborated. We find that the simple LTE approach can safely be applied for the low molecular transitions only, while it significantly overestimates the intensities of the upper lines. In contrast, the Full Escape Probability (FEP) approximation can safely be used for the upper transitions ($J_{\rm up} \ga 3$) but it is not appropriate for the lowest transitions because of the maser effect. In general, the molecular lines in protoplanetary disks are partly subthermally excited and require more sophisticated approximate line radiative transfer methods. We analyze a number of approximate methods, namely, LVG, VEP (Vertical Escape Probability) and VOR (Vertical One Ray) and discuss their algorithms in detail. In addition, two modifications to the canonical Monte Carlo algorithm that allow a significant speed up of the line radiative transfer modeling in rotating configurations by a factor of 10--50 are described.
description: 47 pages, 12 figures, accepted for publication in ApJ
Can raw milk cheese and pasteurised milk cheese coexist? Unthinkable or never really considered?
Creators: name: De Sainte Marie, Christine
name: Mariani, Mariagiulia
name: Millet, Morgane
name: Cerdan, Claire
name: Casabianca, François
name: De Sainte Marie, Christine
name: Mariani, Mariagiulia
name: Millet, Morgane
name: Cerdan, Claire
name: Casabianca, François
Publisher: name: Unknown
Year: 2020
Subjects: subject: Agricultural and Food Policy
subject: Community/Rural/Urban Development
subject: Consumer/Household Economics
subject: Coexistence
subject: Cheese
subject: Geographical indications
subject: Rawmilk
subject: terroir niche
subject: Strategic niche management

description: This article examines the contentious issue of the coexistence of cheese made from raw milk and cheese made from pasteurised milk in areas of protected designation of origin (PDOs). The French PDO system is held to be the benchmark of the international system of geographical indications (GIs). Drawing on the multi-level perspective framework of socio-technical transitions, we conceptualise PDO cheeses as a “niche” nested within a dominant regime that promotes pasteurisation as the standard technology to control pathogens in milk. Careful examination of statistical data and the specifications for PDO cheeses shows that raw milk is experiencing an upturn in domestic production, which we relate to the reinforcement of the regulatory frameworks governing protection of GIs.We investigate more fully the steady increase in raw milk use by studying two contrasting cases of PDO cheeses (Saint-Nectaire and Ossau- Iraty), in which the confrontation between technologies is internalised. Analysis of local innovation pathways highlights a series of key decisions that strengthen the position of raw milk from the farm to the marketplace, namely grass-feeding, limiting herd productivity, technology-specific identification marks, and redistribution of decision-making power among stakeholders. Regulatory mechanisms that counterbalance the pressures of the regime by strategic management of the “terroir” niche are identified and discussed.We argue that shifting the focus from niche/regime interaction towards the internal dynamics of niches sheds light on the conditions of a coexistence of apparently antagonistic models of production in agri-food networks.
An in-depth analysis of the differentially expanding star cluster Stock 18 (Villafranca O-036) using Gaia DR3 and ground-based data
Creators: name: Apellániz, J. Maíz
name: Youssef, A. R.
name: El-Nawawy, M. S.
name: Elsanhoury, W. H.
name: Sota, A.
name: González, M. Pantaleoni
name: Ahmed, A.
Publisher: name: arXiv
Year: 2024
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: (ABRIDGED)
 CONTEXT: The Villafranca project is combining Gaia data with ground-based surveys to analyze Galactic stellar groups with OB stars.
 AIMS: We want to analyze Stock 18 within the Villafranca project, a very young stellar cluster with a symmetrical and compact H II region around it.
 METHODS: We analyze the core, massive-star population, extinction, distance, membership, internal dynamics, density profile, age, IMF, total mass, stellar variability, and Galactic location of Stock 18 with Gaia data and ground-based spectroscopy.
 RESULTS: Stock 18 is a very young (~1.0 Ma) cluster located at a distance of 2.91+-0.10 kpc dominated by the GLS 13 370 system, whose primary is an O9 V star. We propose that Stock 18 was in a very compact state (~0.1 pc) about 1.0 Ma ago and that most massive stars were ejected at that time without significantly affecting the less massive stars as a result of multi-body dynamical interactions. Given its age close to 1.0 Ma, the dynamical interactions took place very soon after massive star formation. Well defined expanding stellar clusters have been observed before but none as young as this one. The IMF is top heavy but if we discard the ejected ones it becomes nearly canonical. Therefore, this is another example in addition to the one we previously found (the Bermuda cluster) of (a) a very young cluster with an already evolved PDMF (b) that has significantly contributed to the future population of free-floating compact objects. If confirmed in more clusters, the number of such compact objects may be higher in the Milky Way than previously thought. Stock 18 has a variable extinction with an average value of R_5495 higher than the canonical one of 3.1. The cluster is above our Galactic mid-plane and has a distinct motion with respect to its surrounding old population, which is possibly an influence of the Perseus spiral arm.
description: Accepted for publication in A&A
The diversity of love : multiple voicing in the narrator of Troilus and Crisey De
Creators: name: Okun, Maureen Jeannette
Publisher: name: University of British Columbia
Year: 2010

description: In Geoffrey Chaucer's Troilus and Criseyde, love is not a simple matter. Critics have long noted the apparent disparity between the poem's larger focus on the worldly love of the main characters and the sudden call for a love of God in the poem's closing stanzas, but even the secular love of Troilus and Criseyde exists in several forms that are often incompatible with each other. Presented alongside the divine Christian love are a courtly love inspired by the pagan Cupid, a simple lust of the flesh, a human love that nevertheless participates in the binding love of creation, and a transitory love that is a gift of changeable Fortune. While many critics argue that God's love is the dominant form against which all others must be measured, this thesis puts forth the alternative that no one kind of love in the poem has precedence; it is on the plurality of attitudes towards love that the poem focuses. The much-discussed narrator of Troilus and Criseyde facilitates this view of the poem. While we might expect this storyteller's extensive commentary on the theme of love to lead us to an understanding of love's role in the poem, the narrator's discussion is itself ambiguous; he holds all the perspectives on love that his story contains and does not consistently privilege one above another. His own disjunctive attitudes encourage us to see him not as a well-rounded character but as a collection of fragmented viewpoints, each with its own voice and each a reflection of the attitudes within the story itself. Although together these voices have the apparent authority of their role as storyteller, as a whole, the narrator repeatedly points to his inability to shoulder the responsibility for meaning that his role calls for. By providing misleading allusions to previous "auctores," he also confounds any attempt to search for authority in sources outside the text. We are made aware that clues to love's meaning in the poem cannot be found in the conventional places; we must ourselves decide which of the many views of love holds precedence. The narrator's plurality of voices is thus the key to the nature of love in Troilus and Criseyde; his many attitudes reflect the richly various possibilities open to us in the non-fictional world.
Microscopic mechanism for cold denaturation
Creators: name: Dias, Cristiano L.
name: Ala-Nissila, Tapio
name: Karttunen, Mikko
name: Vattulainen, Ilpo
name: Grant, Martin
Publisher: name: arXiv
Year: 2007
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: We elucidate the mechanism of cold denaturation through constant-pressure simulations for a model of hydrophobic molecules in an explicit solvent. We find that the temperature dependence of the hydrophobic effect is the driving force/induces/facilitates cold denaturation. The physical mechanism underlying this phenomenon is identified as the destabilization of hydrophobic contact in favor of solvent separated configurations, the same mechanism seen in pressure induced denaturation. A phenomenological explanation proposed for the mechanism is suggested as being responsible for cold denaturation in real proteins.
Computational Micromagnetics based on Normal Modes: bridging the gap between macrospin and full spatial discretization
Creators: name: Perna, S.
name: Bruckner, F.
name: Serpico, C.
name: Suess, D.
name: d'Aquino, M.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Other Condensed Matter (cond-mat.other)
subject: Pattern Formation and Solitons (nlin.PS)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: The Landau-Lifshitz equation governing magnetization dynamics is written in terms of the amplitudes of normal modes associated with the micromagnetic system's appropriate ground state. This results in a system of nonlinear ordinary differential equations (ODEs), the right-hand side of which can be expressed as the sum of a linear term and nonlinear terms with increasing order of nonlinearity (quadratic, cubic, etc.). The application of the method to nanostructured magnetic systems demonstrates that the accurate description of magnetization dynamics requires a limited number of normal modes, which results in a considerable improvement in computational speed. The proposed method can be used to obtain a reduced-order dynamical description of magnetic nanostructures which allows to adjust the accuracy between low-dimensional models, such as macrospin, and micromagnetic models with full spatial discretization. This new paradigm for micromagnetic simulations is tested for three problems relevant to the areas of spintronics and magnonics: directional spin-wave coupling in magnonic waveguides, high power ferromagnetic resonance in a magnetic nanodot, and injection-locking in spin-torque nano-oscillators. The case studies considered demonstrate the validity of the proposed approach to systematically obtain an intermediate order dynamical model based on normal modes for the analysis of magnetic nanosystems. The time-consuming calculation of the normal modes has to be done only one time for the system. These modes can be used to optimize and predict the system response for all possible time-varying external excitations (magnetic fields, spin currents). This is of utmost importance for applications where fast and accurate system simulations are required, such as in electronic circuits including magnetic devices.
Flavor dependence of unpolarized quark Transverse Momentum Distributions from a global fit
Creators: name: Bacchetta, Alessandro
name: Bertone, Valerio
name: Bissolotti, Chiara
name: Bozzi, Giuseppe
name: Cerutti, Matteo
name: Delcarro, Filippo
name: Radici, Marco
name: Rossi, Lorenzo
name: Signori, Andrea
Publisher: name: arXiv
Year: 2024
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Experiment (nucl-ex)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: We present an extraction of the unpolarized transverse-momentum-dependent parton distribution and fragmentation functions that takes into account possible differences between quark flavors and final-state hadrons. The extraction is based on experimental measurements from Drell-Yan processes and semi-inclusive deep-inelastic scattering, whose combination is essential to distinguish flavor differences. The analysis is carried out at N$^3$LL accuracy. The extracted flavor-dependent distributions give a very good description of the data ($χ^2/N_{\rm dat} = 1.08$). The resulting uncertainties take fully into account also the uncertainties in the determination of the corresponding collinear distributions.
description: Updated version as published in JHEP
Two-loop renormalization of scalar and pseudoscalar fermion bilinears on the lattice
Creators: name: Skouroupathis, A.
name: Panagopoulos, H.
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: FOS: Physical sciences

description: We compute the two-loop renormalization functions, in the RI $^\prime$ scheme, of local bilinear quark operators $\barψΓψ$, where $Γ$ denotes the Scalar and Pseudoscalar Dirac matrices, in the lattice formulation of QCD. We consider both the flavor non-singlet and singlet operators; the latter, in the scalar case, leads directly to the two-loop fermion mass renormalization, $Z_m$. As a prerequisite for the above, we also compute the quark field renormalization, $Z_ψ$, up to two loops. We use the clover action for fermions and the Wilson action for gluons. Our results are given as a polynomial in $c_{SW}$, in terms of both the renormalized and bare coupling constant, in the renormalized Feynman gauge. We also confirm the 1-loop renormalization functions, for generic gauge. Finally, we present our results in the $\bar{MS}$ scheme, for easier comparison with calculations in the continuum. The corresponding results, for fermions in an arbitrary representation, are included in an Appendix.
description: 30 pages, 15 figures. Correction of a minor mistake in the 2-loop result for $Z_S$ and $Z_P$. The mistake affects (very slightly) Eqs.(51-54); the change in numerical values is too small to alter the ensuing plots. All conclusions remain unchanged
On the Conformal forms of the Robertson-Walker metric
Creators: name: Ibison, M.
Publisher: name: arXiv
Year: 2007
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: All possible transformations from the Robertson-Walker metric to those conformal to the Lorentz-Minkowski form are derived. It is demonstrated that the commonly known family of transformations and associated conformal factors are not exhaustive and that there exists another relatively less well known family of transformations with a different conformal factor in the particular case that K = -1. Simplified conformal factors are derived for the special case of maximally-symmetric spacetimes. The full set of all possible cosmologically-compatible conformal forms is presented as a comprehensive table. A product of the analysis is the determination of the set-theoretical relationships between the maximally symmetric spacetimes, the Robertson-Walker spacetimes, and functionally more general spacetimes. The analysis is preceded by a short historical review of the application of conformal metrics to Cosmology.
description: Historical review added. Accepted by J. Math. Phys
Faith without focus : neighbourhood transition and religious change in inner-city Vancouver
Creators: name: Martin, Ronald Bruce
Publisher: name: University of British Columbia
Year: 2010

description: Communities are constantly changing, physically, socially and in terms of the values and ideologies of their residents. This research examines the linkages between neighbourhood transition and religious change both theoretically and empirically in an attempt to discover possible connections between social transition and changes in religious values. Initially, literature discussing both neighbourhood transition and religious change and secularization are discussed. This is followed by an attempt to integrate these two bodies of theory, making reference to studies which have attempted to link religious changes to demographic variables. This literature review provides the framework for an examination of social and religious changes in the three inner-city Vancouver neighbourhoods of Fairview, Kitsilano and West Point Grey. Information on these neighbourhoods is derived from census and denominational statistics, city directories and other sources including newspapers, local fiction and interviews with residents. Emerging from the study are indications of linkages between neighbourhood transition and religious change. Although the case studies emphasize that the interaction is very complex, general demographic variables including age, sex, ethnicity, education, occupation, mobility and family status, plus less well-defined cultural values related to post-industrial emphases on aestheticism appear to be related to both traditional religious involvement and the prevalence of new religious movements and other less formalized ideologies. Traditional religions appear to be particularly weak in neighbourhoods with many university-educated, professional young singles and childless couples who are very mobile and whose values include the enjoyment of social and cultural amenities and self-actualization. However these are the same communities where new religious movements and alternative ideologies appear to flourish. More stable, family-oriented neighbourhoods seem to have stronger traditional churches and fewer alternative belief systems. In conclusion, while a theoretical literature on neighbourhood transition frequently ignores religious changes and writing on religion frequently ignores spatial differences, this thesis attempts to combine these two bodies of theory and empirically examine interactions between social and religious changes. What emerges is a complex picture, supporting secularization theory by documenting the decline of traditional churches in some contexts, yet recognizing that while traditional churches decline, other belief systems frequently emerge.
Down-conversion of quantum fluctuations of photonic heat current in a circuit
Creators: name: Karimi, Bayan
name: Pekola, Jukka P.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We discuss the non-zero frequency noise of heat current with the explicit example of energy carried by thermal photons in a circuit. Instead of the standard circuit modelling that gives a convenient way of predicting time-averaged heat current, we describe a setup composed of two resistors forming the heat baths by collections of bosonic oscillators. In terms of average heat transport this model leads to identical results with the conventional one, but besides this, it yields a convenient way of dealing with noise as well. The non-zero frequency heat current noise does not vanish in equilibrium even at zero temperature, the result that is known for, e.g., electron tunneling. We present a modulation method that can convert the difficult-to-measure high frequency quantum noise down to zero frequency.
Effect of Nozzle Curvature on Supersonic Gas Jets Used in Laser-Plasma Acceleration
Creators: name: Zhou, Ocean
name: Tsai, Hai-En
name: Ostermayr, Tobias M.
name: Fan-Chiang, Liona
name: van Tilborg, Jeroen
name: Schroeder, Carl B.
name: Esarey, Eric
name: Geddes, Cameron G. R.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Plasma Physics (physics.plasm-ph)
subject: Accelerator Physics (physics.acc-ph)
subject: Applied Physics (physics.app-ph)
subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: Supersonic gas jets produced by converging-diverging (C-D) nozzles are commonly used as targets for laser-plasma acceleration (LPA) experiments. A major point of interest for these targets is the gas density at the region of interaction where the laser ionizes the gas plume to create a plasma, providing the acceleration structure. Tuning the density profiles at this interaction region is crucial to LPA optimization. A "flat-top" density profile is desired at this line of interaction to control laser propagation and high energy electron acceleration, while a short high-density profile is often preferred for acceleration of lower-energy tightly-focused laser-plasma interactions. A particular design parameter of interest is the curvature of the nozzle's diverging section. We examine three nozzle designs with different curvatures: the concave "bell", straight conical and convex "trumpet" nozzles. We demonstrate that, at mm-scale distances from the nozzle exit, the trumpet and straight nozzles, if optimized, produce "flat-top" density profiles whereas the bell nozzle creates focused regions of gas with higher densities. An optimization procedure for the trumpet nozzle is derived and compared to the straight nozzle optimization process. We find that the trumpet nozzle, by providing an extra parameter of control through its curvature, is more versatile for creating flat-top profiles and its optimization procedure is more refined compared to the straight nozzle and the straight nozzle optimization process. We present results for different nozzle designs from computational fluid dynamics (CFD) simulations performed with the program ANSYS Fluent and verify them experimentally using neutral density interferometry.
description: 14 pages, 16 figures, 5 tables
Visibilidad online en estudiantes de doctorado de  Informática y Biblioteconomía y Documentació
Creators: name: Boté, Juan-José
Publisher: name: Zenodo
Year: 2019
Subjects: visiblidad online, estudiantes de doctorado, redes sociales, universidad

description: Este póster forma parte de un  estudio finalizado en 2018. En este caso, se analiza la visibilidad en las redes sociales.  Los participantes son  los estudiantes de doctorado en  Ingeniería de Sistemas e Informática   Informática de la Universidad de  Zaragoza y los estudiantes de  doctorado en Biblioteconomía y  Documentación de la Universitat de Barcelona.

Este póster está realizado para el IX Encuentro Ibérico EDICIC 2019, 9 - 11 julio de 2019, Facultat de Biblioteconomia i Documentació - Universitat de Barcelona Melcior de Palau, 140 - 08014 Barcelona
Self-Similar Solutions to the Compressible Euler Equations and their Instabilities
Creators: name: Biasi, Anxo
Publisher: name: arXiv
Year: 2021
Subjects: subject: Analysis of PDEs (math.AP)
subject: Mathematical Physics (math-ph)
subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: This paper addresses the construction and the stability of self-similar solutions to the isentropic compressible Euler equations. These solutions model a gas that implodes isotropically, ending in a singularity formation in finite time. The existence of smooth solutions that vanish at infinity and do not have vacuum regions was recently proved and, in this paper, we provide the first construction of such smooth profiles, the first characterization of their spectrum of radial perturbations as well as some endpoints of unstable directions. Numerical simulations of the Euler equations provide evidence that one of these endpoints is a shock formation that happens before the singularity at the origin, showing that the implosion process is unstable.
description: v3: additional discussions in section 4 and appendix A, published version
title: Studierende in Luxemburg
Creators: name: Gewinner, Irina
name: Haas, Christina
name: Hadjar, Andreas
Publisher: name: Luxembourg Centre for Educational Testing (LUCET) & Service de Coordination de la Recherche et de l’Innovation pédagogiques et technologiques (SCRIPT)
Year: 2021

description: Nationaler Bildungsbericht Luxemburg 2021
Increasing the Capability of the Process of Placing Inserts in Foundry Moulds
Creators: name: Jaworski, J.
name: Kluz, R.
name: Trzepieciński, T.
Publisher: name: The Katowice Branch of the Polish Academy of Sciences
Year: 2018
Subjects: process capability indices
mechanisation and automatisation of casting processes
product development
foundry robotic automation

description: Archives of Foundry Engineering continues the publishing activity
 started by Foundry Commission of the Polish Academy of Sciences (PAN) in
 Katowice in 1978. The initiator of it was the first Chairman Professor
 Dr Eng. Wacław Sakwa – Corresponding Member of PAN, Honorary Doctor of
 Czestochowa University of Technology and Silesian University of
 Technology. This periodical first name was „Solidification of Metals and
 Alloys” , and made possible to publish the results of works achieved in
 the field of the Basic Problems Research Cooperation. The subject of
 publications was related to the title of the periodical and concerned
 widely understand problems of metals and alloys crystallization in a
 casting mold. In 1978-2000 the 44 issues have been published. Since 2001
 the Foundry Commission has had patronage of the annually published
 “Archives of Foundry” and since 2007 quarterly published “Archives of
 Foundry Engineering”. Thematic scope includes scientific issues of
 foundry industry:

 Theoretical Aspects of Casting Processes,

 Innovative Foundry Technologies and Materials,

 Foundry Processes Computer Aiding,

 Mechanization, Automation and Robotics in Foundry,

 Transport Systems in Foundry,

 Castings Quality Management,

 Environmental Protection.
description: This article discusses the issue of the preparation of the foundry moulds with the use of an industrial robot. The methodology is presented
for the determination of the process capacity index for placing inserts with flat and cylindrical faces. On the basis of the relationships
developed, the process capability indices were determined at various points in the workspace, which are characterised by different values
of the repeatability positioning error. It was shown that the value of the process capacity index can be increased by the selection of a
suitable location for the process of placing the inserts in the workspace. It should also be noted that the value of the process's capability
index depends on the selection of the place in the robot workspace where the process is carried out. Implementation of the joining process
at an analysed point in the robot workspace leads to an increase of the process capability index MCp for inserts with flat faces up to 1.1
(+4.5%) and for inserts with cylindrical faces up to 1.3. This results in an increase of 13% to a level corresponding to the global standard
for process reliability (MCp = 1.33).