cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Type-II Majoron Dark Matter
Creators: name: Biggio, Carla
name: Calibbi, Lorenzo
name: Ota, Toshihiko
name: Zanchini, Samuele
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: We discuss in detail the possibility that the ``type-II majoron'' -- that is, the pseudo Nambu-Goldstone boson that arises in the context of the type-II seesaw mechanism if the lepton number is spontaneously broken by an additional singlet scalar -- account for the dark matter (DM) observed in the universe. We study the requirements the model's parameters have to fulfill in order to reproduce the measured DM relic abundance through two possible production mechanisms in the early universe, freeze-in and misalignment, both during a standard radiation-dominated era and early matter domination. We then study possible signals of type-II majoron DM and the present and expected constraints on the parameter space that can be obtained from cosmological observations, direct detection experiments, and present and future searches for decaying DM at neutrino telescopes and cosmic-ray experiments. We find that -- depending on the majoron mass, the production mechanism, and the vacuum expectation value of the type-II triplet -- all of the three decay modes (photons, electrons, neutrinos) of majoron DM particles can yield observable signals at future indirect searches for DM. Furthermore, in a corner of the parameter space, detection of majoron DM is possible through electron recoil at running and future direct detection experiments.
description: 23 pages + appendices and bibliography, 6 figures; v2: typos corrected, references and comments added, conclusions unchanged, version accepted for publication in PRD
Surface-Modified Upconverting Microparticles and Nanoparticles for Use in Click Chemistries
Creators: name: Mader, Heike S.
name: Link, Martin
name: Achatz, Daniela E.
name: Uhlmann, Katrin
name: Li, Xiaohua
name: Wolfbeis, Otto S.
Publisher: name: Universität Regensburg
Year: 2010
Subjects: subject: biotin; click chemistry; fluorescence; nanoparticles; upconversion
subject: 540 Chemie

description: A method is described for modifying the surface of upconverting microparticles (UCμPs) and nanoparticles (UCNPs) such that they become amenable to click chemistry. Respective reagents are presented and used in both kinds of particles, either directly or in combination with tetraethoxysilane. The particles also were labeled by using the click reaction, a) with fluorophores to yield materials that have emission colors that depend on the wavelength of excitation; b) with maleinimido groups (so to obtain labels for thiols), and c) with biotin (to make them useful for affinity studies based on the biotin–streptavidin system). We believe that both the UCμPs and UCNPs have the potential of being used in numerous areas including upconversion imaging, biolabeling, and derivatization, but also in encoding and security.
Nonlinear spin dynamics of ferromagnetic ring in the vortex state and its application for spin-transfer nano-oscillator
Creators: name: Uzunova, Vera
name: Ivanov, Boris A.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences
subject: J.2

description: We study a nonlinear spin dynamics of a ferromagnetic ring in a vortex state induced by the spin-polarized current. We also suggest to use the ferromagnetic ring as a free layer of a coreless vortex spin-transfer nano-oscillator. The calculated working frequency is about several GHz, that is much higher than the gyromode frequency of the disk-based vortex oscillator. The response of the vortex-state ring to the spin-polarized current has hysteretic behavior with the reasonable values of the thresholds current densities: ignition threshold is about $10^{8} \text{A}\text{cm}^{-2}$, and elimination current to maintain the oscillations has much lower values about $10^{6} \text{A} \text{cm}^{-2}$. The output signal can be extracted by the help of the inverse spin Hall effect or by the giant magnetoresistance. The output electromotive force averaged over all sample vanishes, and we suggest to use a ferromagnetic ring or disk in a vortex state as a GMR analyzer. For an inverse spin Hall analyser we advise to use two heavy metals with different signs of Spin-Hall angle. The ring-based STNO is supposed to increase the areas of practical application of the STNOs.
description: 15 pages, 8 figures
Multiple fluorescent chemical sensing and imaging
Creators: name: Stich, Matthias I. J.
name: Fischer, Lorenz H.
name: Wolfbeis, Otto S.
Publisher: name: Universität Regensburg
Year: 2010
Subjects: subject: 540 Chemie

description: Optical sensors, unlike most others, enable multiple sensing of (bio)chemical species by making use of probes whose signals can be differentiated by spectral and/or temporal resolution. Multiple sensors are of substantial interest for continuous monitoring of chemical parameters in complex samples such as blood, bioreactor fluids, in the chemical industry, aerodynamic research, and when monitoring food quality control, to mention typical examples. Moreover, such sensors enable non-invasive, non-toxic and online detection. We discuss in this critical review the state of the art in terms of spectroscopic principles, materials (mainly indicatorprobes and polymers), and give selected examples for dual and triple sensors along with a look into the future (109 references).
A thermodynamic description of the near- and far-field intensity patterns emerging from multimode nonlinear waveguide arrays
Creators: name: Selim, Mahmoud A.
name: Wu, Fan O.
name: Ren, Huizhong
name: Khajavikhan, Mercedeh
name: Christodoulides, Demetrios
Publisher: name: arXiv
Year: 2022
Subjects: subject: Optics (physics.optics)
subject: Chaotic Dynamics (nlin.CD)
subject: FOS: Physical sciences

description: Nonlinear highly multimode photonic systems are ubiquitous in optics. Yet, the sheer complexity arising from the action of nonlinearity in multimode environments has posed theoretical challenges in describing these systems. In this work, we deploy concepts from optical thermodynamics to investigate the near- and far-field emission intensity patterns emerging from nonlinear waveguide arrays. An exact equation dictating the response of a nonlinear array is derived in terms of the systems invariants that act as extensive thermodynamic variables. In this respect, the near- and far-field characteristics emerging from a weakly nonlinear waveguide lattice are analytically addressed. We show that statistically, these patterns and the resulting far-field brightness are governed by the optical temperature and its corresponding chemical potential. The extensivity associated with the entropy of such configurations is discussed. The thermodynamic results presented here were found to be in good agreement with numerical simulations obtained from nonlinear coupled-mode theory.
description: 11 pages, 11 figures, journal
Fractional Analogous Models in Mechanics and Gravity Theories
Creators: name: Baleanu, Dumitru
name: Vacaru, Sergiu I.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences
subject: 26A33, 35C08, 37K10, 53C60, 53C99, 70S05, 83C15

description: We briefly review our recent results on the geometry of nonholonomic manifolds and Lagrange--Finsler spaces and fractional calculus with Caputo derivatives. Such constructions are used for elaborating analogous models of fractional gravity and fractional Lagrange mechanics.
description: latex2e, 11pt, 11 pages with table of content; it is summary of the results presented in our talk at the 3d Conference on "Nonlinear Science and Complexity", 28--31 July, 2010, \c{C}hankaya University, Ankara, Turkey
GEMRec: Towards Generative Model Recommendation
Creators: name: Guo, Yuanhe
name: Liu, Haoming
name: Wen, Hongyi
Publisher: name: arXiv
Year: 2023
Subjects: subject: Information Retrieval (cs.IR)
subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences

description: Recommender Systems are built to retrieve relevant items to satisfy users' information needs. The candidate corpus usually consists of a finite set of items that are ready to be served, such as videos, products, or articles. With recent advances in Generative AI such as GPT and Diffusion models, a new form of recommendation task is yet to be explored where items are to be created by generative models with personalized prompts. Taking image generation as an example, with a single prompt from the user and access to a generative model, it is possible to generate hundreds of new images in a few minutes. How shall we attain personalization in the presence of "infinite" items? In this preliminary study, we propose a two-stage framework, namely Prompt-Model Retrieval and Generated Item Ranking, to approach this new task formulation. We release GEMRec-18K, a prompt-model interaction dataset with 18K images generated by 200 publicly-available generative models paired with a diverse set of 90 textual prompts. Our findings demonstrate the promise of generative model recommendation as a novel personalization problem and the limitations of existing evaluation metrics. We highlight future directions for the RecSys community to advance towards generative recommender systems. Our code and dataset are available at https://github.com/MAPS-research/GEMRec.
description: Accepted by WSDM 2024 (Demo Track)
Assessment of Detached Eddy Simulation and Sliding Mesh Interface in Predicting Tiltrotor Performance in Helicopter and Airplane Modes
Creators: name: Jia, Feilin
name: Moore, John
name: Wang, Qiqi
Publisher: name: arXiv
Year: 2022
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: This paper presents numerical investigation on performance and flow field of the full-scale XV-15 tiltrotor in both helicopter mode (hovering flight and forward flight) and aeroplane propeller mode using Detached Eddy Simulation, in which the movement of the rotor is achieved using a Sliding Mesh Interface. Comparison of our CFD results against experiment data and other CFD results is performed and presented.
Critical Magnetic Field Ratio of Anisotropic Magnetic Superconductors
Creators: name: Changjan, A.
name: Udomsamuthirun, P.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: The upper critical field, the lower critical field and the critical magnetic field ratio of anisotropic magnetic superconductors are calculated by Ginzburg-Landau theory analytically. The effect of the Ginzburg-Landau parameter(κ_0), magnetic susceptibility(χ) and magnetic-to- anisotropic parameter ratio(θ) on the critical field ratio are considered. We find that the value of critical magnetic field ratio with χ< 0, higher κ_0,and higher θcase are shown the higher value. And, the diamagnetic superconductors with highly anisotropic and the ferromagnetic superconductors are shown the highest and the lowest, respectively.
description: 8 pages, 1 figure
A near-infrared fluorescent probe for monitoring tyrosinase activity
Creators: name: Li, Xiaohua
name: Shi, Wen
name: Chen, Suming
name: Jia, Jia
name: Ma, Huimin
name: Wolfbeis, Otto S.
Publisher: name: Universität Regensburg
Year: 2010
Subjects: subject: 540 Chemie

description: A new cyanine-based near-infrared fluorescent probe has been developed for monitoring tyrosinase activity.
AGILE detection of GeV gamma-ray emission from the SNR W28
Creators: name: Giuliani, A.
name: Tavani, M.
name: Bulgarelli, A.
name: Striani, E.
name: Sabatini, S.
name: Cardillo, M.
name: Fukui, Y.
name: Kawamura, A.
name: Ohama, A.
name: Furukawa, N.
name: Torii, K.
name: Aharonian, F. A.
name: Verrecchia, F.
name: Argan, A.
name: Barbiellini, G.
name: Caraveo, P. A.
name: Cattaneo, P. W.
name: Chen, A. W.
name: Cocco, V.
name: Costa, E.
name: D'Ammando, F.
name: Del Monte, E.
name: De Paris, G.
name: Di Cocco, G.
name: Donnarumma, I.
name: Evangelista, Y.
name: Feroci, M.
name: Fiorini, M.
name: Froysland, T.
name: Fuschino, F.
name: Galli, M.
name: Gianotti, F.
name: Labanti, C.
name: Lapshov, Y.
name: Lazzarotto, F.
name: Lipari, P.
name: Longo, F.
name: Mereghetti, M. Marisaldi.
name: Morselli, A.
name: Moretti, E.
name: Pacciani, L.
name: Pellizzoni, A.
name: Perotti, F.
name: Picozza, P.
name: Pilia, M.
name: Prest, M.
name: Pucella, G.
name: Rapisarda, M.
name: Rappoldi, A.
name: Soffitta, P.
name: Trifoglio, M.
name: Trois, A.
name: Vallazza, E.
name: Vercellone, S.
name: Vittorini, V.
name: Zambra, A.
name: Zanello, D.
name: Pittori, C.
name: Santolamazza, P.
name: Giommi, P.
name: Colafrancesco, S.
name: Salotti, L.
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Supernova remnants (SNRs) are believed to be the main sources of Galactic cosmic rays. Molecular clouds associated with SNRs can produce gamma-ray emission through the interaction of accelerated particles with the concentrated gas. The middle aged SNR W28, for its associated system of dense molecular clouds, provides an excellent opportunity to test this hypothesis. We present the AGILE/GRID observations of SNR W28, and compare them with observations at other wavelengths (TeV and 12CO J=1-->0 molecular line emission). The gamma-ray flux detected by AGILE from the dominant source associated with W28 is (14 +- 5) 10^-8 ph cm^-2 s^-1 for E > 400 MeV. This source is positionally well correlated with the TeV emission observed by the HESS telescope. The local variations of the GeV to TeV flux ratio suggest a difference between the CR spectra of the north-west and south molecular cloud complexes. A model based on a hadronic-induced interaction and diffusion with two molecular clouds at different distances from the W28 shell can explain both the morphological and spectral features observed by AGILE in the MeV-GeV energy range and by the HESS telescope in the TeV energy range. The combined set of AGILE and H.E.S.S. data strongly support a hadronic model for the gamma-ray production in W28.
description: Accepted for publication in Astronomy & Astrophysics Letters
Investigating electrical resistivity of highly compacted bentonite as a monitoring option for nuclear waste repositories
Creators: name: Rahimi, Sepehr
Publisher: name: University of British Columbia
Year: 2017

description: Bentonite clay is an essential component of the engineered barrier systems required around nuclear waste bundles in a deep geological repository (DGR). The bentonite is subject to both thermal and hydraulic gradients which may cause failure of the barrier system compromising the stability of the deep geological repository. Regular monitoring and evaluation of the condition of the highly compacted bentonite (HCB) is the key to the long term safe storage of nuclear waste bundles. The degree of saturation of the bentonite is the most critical parameter used to assess the performance of the material. The thermal and electrical resistivity of highly compacted bentonite samples were measured to develop a relationship based on the degree of saturation of the material. In addition, this research investigated the relationship between total suction and electrical resistivity. Moreover, estimating the microbial activity near the waste bundles is a crucial part of the monitoring-process, because it can lead to microbial induced corrosion (MIC) and jeopardize the safety of the repository. The inherent physical characteristics of highly compacted bentonite, such as high swelling pressure and small pore size, reduce the microbial activity near the used fuel containers, which would reduce or eliminate the possibility of microbial induced corrosion. It is reported in the literature that the microbial activity in the bulk of compacted bentonite can be controlled if the emplaced compacted bentonite has a uniform dry density of more than 1.6 g/cm3 and salt concentrations above 100 g/L for sodium and calcium chloride; these conditions ensure that the swelling pressure is higher than 2 MPa and it keeps the water activity and the average pore size lower than 0.96 and 0.02 μm, respectively. High salinity typically plays a vital role in suppressing the microbial activity in the compacted bentonite. As mentioned above, the electrical resistivity is a powerful tool to monitor the performance of repositories. Following the same procedure, the salinity of the highly compacted bentonite can be monitored by means of electrical resistivity to obtain a clear depiction of the microbial activity within the deep geological repository.
Upconverting luminescent nanoparticles for use in bioconjugation and bioimaging
Creators: name: Mader, Heike Sabine
name: Kele, Peter
name: Saleh, Sayed M.
name: Wolfbeis, Otto S.
Publisher: name: Universität Regensburg
Year: 2010
Subjects: subject: 540 Chemie

description: Upconverting luminescent nanoparticles (UCNPs) display the unique property of emitting visible light following photoexcitation with near-infrared laser light. This results in features such as virtually zero autofluorescence of (biological) matter and easy separation of the emission peaks from stray light. Other features include rather narrow emission bands, very high chemical stability, the lack of bleaching, and the absence of blinking effects. This article reviews the work performed in the past few years with UCNPs in terms of surface modifications, bioconjugation, and optical (cellular) imaging.
The lattices with the continious vorticity as a model for FQHE
Creators: name: Iordanski, S. V.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: It was shown that the including spin of 2d electrons at high magnetic field is possible to remove the divergencies in the cores of the vortex lattice and construct the topologically stable states. These states can be considered as the lattices of skyrmions where the unit cell is mapped on the whole sphere of spin directions.That gives the gapped ground state for electrons and can be used as a model for FQHE.
Conformal Predictive Safety Filter for RL Controllers in Dynamic Environments
Creators: name: Strawn, Kegan J.
name: Ayanian, Nora
name: Lindemann, Lars
Publisher: name: arXiv
Year: 2023
Subjects: subject: Robotics (cs.RO)
subject: FOS: Computer and information sciences

description: The interest in using reinforcement learning (RL) controllers in safety-critical applications such as robot navigation around pedestrians motivates the development of additional safety mechanisms. Running RL-enabled systems among uncertain dynamic agents may result in high counts of collisions and failures to reach the goal. The system could be safer if the pre-trained RL policy was uncertainty-informed. For that reason, we propose conformal predictive safety filters that: 1) predict the other agents' trajectories, 2) use statistical techniques to provide uncertainty intervals around these predictions, and 3) learn an additional safety filter that closely follows the RL controller but avoids the uncertainty intervals. We use conformal prediction to learn uncertainty-informed predictive safety filters, which make no assumptions about the agents' distribution. The framework is modular and outperforms the existing controllers in simulation. We demonstrate our approach with multiple experiments in a collision avoidance gym environment and show that our approach minimizes the number of collisions without making overly-conservative predictions.
Opto-Chemical Micro-Capillary Clocks
Creators: name: Wilhelm, S.
name: Wolfbeis, Otto S.
Publisher: name: Universität Regensburg
Year: 2010
Subjects: subject: Optical timer - Chromogenic chemistry - Indigo - Oxygen - Clock - Poly(ethylene glycol)
subject: 540 Chemie

description: Opto-chemical capillary clocks are presented that are based on the measurement of a colored segment in a microchannel (a capillary). Color is created by a chromogenic chemistry involving the oxidation of a (virtually colorless) leuco-dye. Poly(ethylene glycol) (PEG) is used as a solvent, and indigo and thioindigo (in their reduced leuco forms) act as oxygen-sensitive dyes. The clock is started by removing one seal at the end of the capillary. A visible color change occurs as air diffuses into the microchannel due to an irreversible color reaction. The length of the colored segment is proportional to the time elapsed. PEGs of different average molar mass affect the diffusion rate of oxygen in the microchannel and thereby affect the rate of the migration of the color front. Both temperature and relative humidity exert a strong effect. Six types of such clocks are described that enable times to be determined in the range from 1 day to 6 months, possibly of even decades.
Gravitational waves and nonaxisymmetric oscillation modes in mergers of compact object binaries
Creators: name: Stergioulas, Nikolaos
name: Bauswein, Andreas
name: Zagkouris, Kimon
name: Janka, Hans-Thomas
Publisher: name: arXiv
Year: 2011
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: We study the excitation of nonaxisymmetric modes in the post-merger phase of binary compact object mergers and the associated gravitational wave emission. Our analysis is based on general-relativistic simulations, in the spatial conformal flatness approximation, using smoothed-particle-hydrodynamics for the evolution of matter, and we use a set of equal and unequal mass models, described by two nonzero-temperature hadronic equations of state and by one strange star equation of state. Through Fourier transforms of the evolution of matter variables, we can identify a number of oscillation modes, as well as several nonlinear components (combination frequencies). We focus on the dominant m=2 mode, which forms a triplet with two nonlinear components that are the result of coupling to the quasiradial mode. A corresponding triplet of frequencies is identified in the gravitational wave spectrum, when the individual masses of the compact objects are in the most likely range of 1.2 to 1.35 $M_\odot$. We can thus associate, through direct analysis of the dynamics of the fluid, a specific frequency peak in the gravitational wave spectrum with the nonlinear component resulting from the difference between the m=2 mode and the quasiradial mode. Once such observations become available, both the m=2 and quasiradial mode frequencies could be extracted, allowing for the application of gravitational-wave asteroseismology to the post-merger remnant and leading to tight constraints on the equation of state of high-density matter.
description: 11 pages, 8 figures, submitted to MNRAS
Temperature-Sensitive Luminescent Nanoparticles and Films Based on a Terbium (III) Complex Probe
Creators: name: Sun, Li-Ning
name: Yu, Jiangbo
name: Peng, Hongshang
name: Zhang, Jin Z.
name: Shi, Li-Yi
name: Wolfbeis, Otto S.
Publisher: name: Universität Regensburg
Year: 2010
Subjects: subject: 540 Chemie

description: The terbium-tris[(2-hydroxy-benzoyl)-2-aminoethyl]amine complex (Tb-THBA) with its high color purity, long luminescence lifetime, and high quantum yield has been found to be a viable indicator for the optical sensing of temperature. Both its luminescence intensity and its lifetime strongly depend on temperature in the range from 15 to 65 °C. When photoexcited at 341 nm, it displays typical Tb3+ ion emission bands with the strongest peak at 546 nm and a typical decay time of 1.15 ms at 15 °C. The probe is shown to be excellent for sensing temperature, as demonstrated in two kinds of optical sensor membranes. In the first, it was incorporated into a highly biocompatible polyurethane hydrogel to form a sensing film. In the second, Tb-THBA was converted into nanoparticles with a mean diameter of 10 nm that were then incorporated into a film of poly(vinyl alcohol). The two films display a remarkably high sensitivity toward temperature change, both in luminescence intensity and in luminescence decay time, making them promising for the optical sensing and imaging of temperature in the physiologically relevant temperature range. The mechanism behind the temperature sensing has been investigated using a combination of experimental techniques. For the complex in solution or the polyurethane sensing film, the emission intensity and lifetime decrease with increasing temperature, which is expected and attributed to thermal deactivation of the excited state. For the nanoparticles in solution, however, an interesting and unusual temperature dependence of the emission intensity has been observed. The emission intensity was found to increase with increasing temperature in the range of 20−65 °C, which is possibly due to a shift in equilibrium from a less luminescent species or state to a more luminescent species or state. For the nanoparticle films, this unusual behavior disappeared, likely due to the lack of such an equilibrium shift in the films.
Lorentz Violation by Quark Condensation
Creators: name: Xiong, Chi
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: At the TeV scale, heavy quarks, for example the 4th generation quarks of the Standard Model with four generations, can form condensates which dynamically break the electroweak symmetry. A dense quark system may form other types of condensates which dynamically break the Lorentz symmetry. These condensates are described by a Nambu-Jona-Lasinio type effective action, similar to the quark condensation models in hadronic matter with finite density. The vacua corresponding to these two types of condensates compete for the global minimum of the effective potential, depending on the energy scale and the related strong dynamics. The resultant Goldstone gauge boson may produce observable effects in relativistic heavy-ion colliders.
description: 5 pages, 1 figure. Presented at the Fifth Meeting on CPT and Lorentz Symmetry, Bloomington, Indiana, June 28-July 2, 2010
Novel multicolor fluorescently labeled silica nanoparticles for interface fluorescence resonance energy transfer to and from labeled avidin
Creators: name: Saleh, Sayed M.
name: Müller, Rainer
name: Mader, Heike S.
name: Dürkop, Axel
name: Wolfbeis, Otto S.
Publisher: name: Universität Regensburg
Year: 2010
Subjects: subject: Silica nanoparticles - Surface modification - Near-infrared label - FRET - Surface affinity assay - Biotin
subject: 540 Chemie

description: Fluorescent silica nanoparticles (SiNPs) were prepared by covalent attachment of fluorophores to the amino-modified surface of SiNPs with a typical diameter of 15 nm. The SiNPs are intended for use in novel kinds of fluorescence resonance energy transfer (FRET)-based affinity assays at the interface between nanoparticle and sample solution. Various labels were employed to obtain a complete set of colored SiNPs, with excitation maxima ranging from 337 to 659 nm and emission maxima ranging from 436 nm to the near infrared (710 nm). The nanoparticles were characterized in terms of size and composition using transmission electron microscopy, thermogravimetry, elemental analysis, and dynamic light scattering. The surface of the fluorescent SiNPs was biotinylated, and binding of labeled avidin to the surface was studied via FRET in two model cases. In the first, FRET occurs from the biotinylated fluorescent SiNP (the donor) to the labeled avidin (the acceptor). In the second, FRET occurs in the other direction. Aside from its use in the biotin–avidin system, such SiNPs also are believed to be generally useful fluorescent markers in various kinds of FRET assays, not the least because the fluorophore is located on the surface of the SiNPs (and thus always much closer to the second fluorophore) rather than being doped deep in its interior.
Optical Ammonia Sensor Based on Upconverting Luminescent Nanoparticles
Creators: name: Mader, Heike S.
name: Wolfbeis, Otto S.
Publisher: name: Universität Regensburg
Year: 2010
Subjects: subject: 540 Chemie

description: The sensor exploits the phenomenon of upconversion luminescence and is based on (a) the use of upconverting nanoparticles (UCNPs) of the NaYF4:Yb,Er type that can be excited with 980 nm laser light to give a green and red luminescence and (b) the pH probe phenol red immobilized in a polystyrene matrix. Exposure of the sensor film to ammonia causes a strong increase in the 560 nm absorption of the pH probe which, in turn, causes the green emission of the UCNPs to be screened off. The red emission of the UCNPs, in contrast, remains unaffected by ammonia and can serve as a reference signal. Due to the use of 980 nm as the excitation light source, the optical signal obtained is completely free of background visible luminescence of the sample and of scattered light. This is highly advantageous in the case of sensing ammonia in complex matrixes.
Would You Mind Me if I Pass by You? Socially-Appropriate Behaviour for an Omni-based Social Robot in Narrow Environment
Creators: name: Senft, Emmanuel
name: Satake, Satoru
name: Kanda, Takayuki
Publisher: name: arXiv
Year: 2022
Subjects: subject: Robotics (cs.RO)
subject: FOS: Computer and information sciences

description: Interacting physically with robots and sharing environment with them leads to situations where humans and robots have to cross each other in narrow corridors. In these cases, the robot has to make space for the human to pass. From observation of human-human crossing behaviours, we isolated two main factors in this avoiding behaviour: body rotation and sliding motion. We implemented a robot controller able to vary these factors and explored how this variation impacted on people's perception. Results from a within-participants study involving 23 participants show that people prefer a robot rotating its body when crossing them. Additionally, a sliding motion is rated as being warmer. These results show the importance of social avoidance when interacting with humans.
description: Accepted at HRI 2020, March 24-26, 2020, Virtual Event, UK. (https://dl.acm.org/doi/pdf/10.1145/3319502.3374812)
Spatially resolved XMM-Newton analysis and a model of the nonthermal emission of MSH 15-52
Creators: name: Schöck, F. M.
name: Büsching, I.
name: de Jager, O. C.
name: Eger, P.
name: Vorster, M. J.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We present an X-ray analysis and a model of the nonthermal emission of the pulsar wind nebula (PWN) MSH15-52. We analyzed XMM-Newton data to obtain the spatially resolved spectral parameters around the pulsar PSRB1509-58. A steepening of the fitted power-law spectra and decrease in the surface brightness is observed with increasing distance from the pulsar. In the second part of this paper, we introduce a model for the nonthermal emission, based on assuming the ideal magnetohydrodynamic limit. This model is used to constrain the parameters of the termination shock and the bulk velocity of the leptons in the PWN. Our model is able to reproduce the spatial variation of the X-ray spectra. The parameter ranges that we found agree well with the parameter estimates found by other authors with different approaches. In the last part of this paper, we calculate the inverse Compton emission from our model and compare it to the emission detected with the H.E.S.S. telescope system. Our model is able to reproduce the flux level observed with H.E.S.S., but not the spectral shape of the observed TeV γ-ray emission.
description: Accepted for publication in A&A, 9 pages, 15 figures
Ratiometric fluorescent nanoparticles for sensing temperature
Creators: name: Peng, Hong-Shang
name: Huang, Shi-Hua
name: Wolfbeis, Otto S.
Publisher: name: Universität Regensburg
Year: 2010
Subjects: subject: Ratiometric fluorescence - Nanoparticles - Europium chelate - Temperature sensing
subject: 540 Chemie

description: A ratiometric type of fluorescent nanoparticle was prepared via an encapsulation–reprecipitation method. By introducing an alkoxysilanized dye as a reference, the nanoparticles (NPs) give both a green and a red fluorescence under one single-wavelength excitation. The resulted ratiometric fluorescence is found to be highly temperature-dependent in the physiological range (25–45 °C), with an intensity temperature sensitivity of −4.0%/°C. Given the small size (20–30 nm in diameter) and biocompatible nature (silica out layer), such kind of NPs were very promising as temperature nanosensors for cellular sensing and imaging.
Analytic density of states of two-dimensional Chern insulator
Creators: name: Uzunova, Vera
name: Byczuk, Krzysztof
Publisher: name: arXiv
Year: 2023
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We present analytic expressions for the density of states and its consistent derivation for the two-dimensional Qi-Wu-Zhang (QWZ) Hamiltonian, a generic model for the Chern topological insulators of class A. This density of states is expressed in terms of elliptical integrals. We discuss and plot special cases of the dispersion relations and the corresponding densities of states. Spectral moments are also presented. The exact formulae ought to be useful in determining physical properties of the non-interacting Chern insulators and within the dynamical mean-field theory for interacting fermions with the QWZ Hamiltonian in the non-interacting limit.
description: 12 pages, 17 figures
Wide field CO J = 3->2 mapping of the Serpens Cloud Core
Creators: name: Dionatos, O.
name: Nisini, B.
name: Codella, C.
name: Giannini, T.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Context. Outflows provide indirect means to get an insight on diverse star formation associated phenomena. On scales of individual protostellar cores, outflows combined with intrinsic core properties can be used to study the mass accretion/ejection process of heavily embedded protostellar sources. Methods. An area comprising 460"x230" of the Serpens cloud core has been mapped in 12 CO J = 3\to 2 with the HARP-B heterodyne array at the James Clerk Maxwell Telescope; J = 3\to 2 observations are more sensitive tracers of hot outflow gas than lower J CO transitions; combined with the high sensitivity of the HARP-B receptors outflows are sharply outlined, enabling their association with individual protostellar cores. Results. Most of ~20 observed outflows are found to be associated with known protostellar sources in bipolar or unipolar configurations. All but two outflow/core pairs in our sample tend to have a projected orientation spanning roughly NW-SE. The overall momentum driven by outflows in Serpens lies between 3.2 and 5.1 x 10^(-1) M\odot km s^(-1), the kinetic energy from 4.3 to 6.7 x 10^(43) erg and momentum flux is between 2.8 and 4.4 x 10^(-4) M\odot km s^(-1) yr^(-1). Bolometric luminosities of protostellar cores based on Spitzer photometry are found up to an order of magnitude lower than previous estimations derived with IRAS/ISO data. Conclusions. We confirm the validity of the existing correlations between the momentum flux and bolometric luminosity of Class I sources for the homogenous sample of Serpens, though we suggest that they should be revised by a shift to lower luminosities. All protostars classified as Class 0 sources stand well above the known Class I correlations, indicating a decline in momentum flux between the two classes.
description: 15 pages, 10 figures, accepted for publication in A&A
Magnetic Phases of Bilayer Quantum-Dot Hubbard Model Plaquettes
Creators: name: Buterakos, Donovan
name: Sarma, Sankar Das
Publisher: name: arXiv
Year: 2023
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: It has been demonstrated that small plaquettes of quantum dot spin qubits are capable of simulating condensed matter phenomena which arise from the Hubbard model, such as the collective Coulomb blockade and Nagaoka ferromagnetism. Motivated by recent materials developments, we investigate a bilayer arrangement of quantum dots with four dots in each layer which exhibits a complex ground state behavior. We find using a generalized Hubbard model with long-range Coulomb interactions, several distinct magnetic phases occur as the Coulomb interaction strength is varied, with possible ground states that are ferromagnetic, antiferromagnetic, or having both one antiferromagnetic and one ferromagnetic layer. We map out the full phase diagram of the system as it depends on the inter- and intra-layer Coulomb interaction strengths, and find that for a single layer, a similar but simpler effect occurs. We also predict interesting contrasts among electron, hole, and electron-hole bilayer systems arising from complex correlation physics. Observing the predicted magnetic configuration in already-existing few-dot semiconductor bilayer structures could prove to be an important assessment of current experimental quantum dot devices, particularly in the context of spin-qubit-based analog quantum simulations.
Improving the Livelihoods of Young People in Nepal: The Contribution of Social Enterprises
Creators: name: Joshi, Rojee
Publisher: name: Australian Catholic University
Year: 2018

description: This thesis examines five cases of social enterprise organisations from Nepal, a geographically challenged, politically volatile country with poor infrastructure, a high poverty gradient, and high levels of social and gender disparity. The study aims to explore how organisations following principles of social enterprise can address the multifaceted challenges of youth unemployment. Specifically, the study aims to understand the contribution of social enterprise organisations to the improvement of livelihoods of young people in Nepal, through job creation and market integration, fundamentally adopting market principles to address development challenges. The research contributes to the body of empirical literature on social enterprises from Nepal, and social value creation processes through the use of empirical evidence. It uses the qualitative method of analysing the social value creation processes which subsequently informs a range of challenges faced by young people attempting to participate in the market. In terms of methodology, the research implemented a three-step process: literature review, an organisational survey, and five qualitative case studies. Thirty-four self-identified social enterprise organisations were used for survey analysis. Five organisations were selected for detailed case analysis. Using cross-case analysis methods, interviews from 17 representatives and 30 young men and women aged 18– 30 were analysed . A combination of development theory, the theory of social entrepreneurship, and youth perspectives, is used in establishing the contribution of social enterprises to the improvement of the livelihoods of young people in Nepal. The overall contribution of social enterprises is unfolding in two distinct ways. The first level of contribution is revealed in the form of organisations attempting to become financially self-sustainable and market-competitive. The second level of contribution is demonstrated by limited social and economic change as immediate outcomes, and chances of significant and sustainable social change in the longer term. By demonstrating the change process at an organisational level as well as at the participants’ level, the study presents a meaningful explanation of a social enterprise model of development in improving livelihood of young people in Nepal.
Bogoliubov Quasiparticle on the Gossamer Fermi Surface in Electron-Doped Cuprates
Creators: name: Xu, Ke-Jun
name: Guo, Qinda
name: Hashimoto, Makoto
name: Li, Zi-Xiang
name: Chen, Su-Di
name: He, Junfeng
name: He, Yu
name: Li, Cong
name: Berntsen, Magnus H.
name: Rotundu, Costel R.
name: Lee, Young S.
name: Devereaux, Thomas P.
name: Rydh, Andreas
name: Lu, Dong-Hui
name: Lee, Dung-Hai
name: Tjernberg, Oscar
name: Shen, Zhi-Xun
Publisher: name: arXiv
Year: 2023
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: In contrast to hole-doped cuprates, electron-doped cuprates consistently exhibit strong antiferromagnetic correlations with a commensurate (π, π) ordering wave vector, leading to the prevalent belief that antiferromagnetic spin fluctuations mediate Cooper pairing in these unconventional superconductors. However, early investigations produced two paradoxical findings: while antiferromagnetic spin fluctuations create the largest pseudogap at "hot spots" in momentum space, Raman scattering and angle-resolved photoemission spectroscopy measurements using the leading-edge method seem to suggest the superconducting gap is also maximized at these locations. This presented a dilemma for spin-fluctuation-mediated pairing: Cooper pairing is strongest at momenta where normal state low energy spectral weight is most suppressed. Here we investigate this dilemma in Nd2-xCexCuO4 using angle-resolved photoemission spectroscopy under significantly improved experimental conditions. The unprecedented signal-to-noise ratio and resolution allow us to directly observe the Bogoliubov quasiparticles, demonstrating the existence and importance of two sectors of states: 1. The reconstructed main band and the states gapped by the antiferromagnetic pseudogap around the hot spots. 2. The gossamer Fermi surface states with distinct dispersion inside the pseudogap, from which Bogoliubov quasiparticle coherence peaks emerge below Tc. Supported by numerical results, we propose that the non-zero modulus of the antiferromagnetic order parameter causes the former, while fluctuations in the antiferromagnetic order parameter orientation are responsible for the latter. Our revelations of the gossamer Fermi surface reconcile the paradoxical observations, deepening our understanding of superconductivity in electron-doped cuprates in particular, and unconventional superconductivity in general.
description: Submitted version 30 pages, 4 main figures, 8 extended data figures. Accepted version in press at Nature Physics
Quantizing Braids and Other Mathematical Objects: The General Quantization Procedure
Creators: name: Lomonaco, Samuel J.
name: Kauffman, Louis H.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences
subject: Primary 81P68, 57M25, 81P15, 57M27, Secondary 20C35

description: Extending the methods from our previous work on quantum knots and quantum graphs, we describe a general procedure for quantizing a large class of mathematical structures which includes, for example, knots, graphs, groups, algebraic varieties, categories, topological spaces, geometric spaces, and more. This procedure is different from that normally found in quantum topology. We then demonstrate the power of this method by using it to quantize braids. This general method produces a blueprint of a quantum system which is physically implementable in the same sense that Shor's quantum factoring algorithm is physically implementable. Mathematical invariants become objects that are physically observable.
Population I Wolf-Rayet Runaway Stars: the Case of WR124 and its Expanding Nebula M1-67
Creators: name: Marchenko, S. V.
name: Moffat, A. F. J.
name: Crowther, P. A.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: In 1997 and 2008 we used the WFPC2 camera on board of the Hubble Space Telescope to obtain two sets of narrow-band H$α$ images of the runaway Wolf-Rayet (WR) star WR 124 surrounded by its nebula M1-67. This two-epoch imaging provides an expansion parallax and thus a practically assumption-free geometric distance to the nebula, d=3.35 +/- 0.67 kpc. Combined with the global velocity distribution in the ejected nebula, this confirms the extreme runaway status of WR 124. WR stars embedded within such ejection nebulae, at the point of core-collapse would produce different supernova characteristics from those expected for stars surrounded by wind-filled cavities. In galaxies with extremely low ambient metallicity, Z <= 10^{-3} Z_Sun, gamma-ray bursts originating from fast-moving runaway WR stars may produce afterglows which appear to be coming from regions with a relatively homogeneous circumburst medium.
description: 13 pages, 2 figures; accepted by ApJL
Chemical design rules for non-fullerene acceptors in organic solar cells
Creators: name: Markina, A.
name: Lin, K. -H.
name: Liu, W.
name: Poelking, C.
name: Firdaus, Y.
name: Villalva, D. R.
name: Khan, J. I.
name: Paleti, S. H. K.
name: Harrison, G. T.
name: Gorenflot, J.
name: Zhang, W.
name: De Wolf, S.
name: McCulloch, I.
name: Anthopoulos, T. D.
name: Baran, D.
name: Laquai, F.
name: Andrienko, D.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Efficiencies of organic solar cells have practically doubled since the development of non-fullerene acceptors (NFAs). However, generic chemical design rules for donor-NFA combinations are still needed. Such rules are proposed by analyzing inhomogeneous electrostatic fields at the donor-acceptor interface. It is shown that an acceptor-donor-acceptor molecular architecture, and molecular alignment parallel to the interface, results in energy level bending that destabilizes the charge transfer state, thus promoting its dissociation into free charges. By analyzing a series of PCE10:NFA solar cells, with NFAs including Y6, IEICO, and ITIC, as well as their halogenated derivatives, it is suggested that the molecular quadrupole moment of ca 75 Debye A balances the losses in the open circuit voltage and gains in charge generation efficiency.
CKU 24: Ibbi-Sîn-Puzur-Numušda 1, version courte (3.1.20)
Creators: name: Attinger, Pascal
Publisher: name: Zenodo
Year: 2019
Subjects: Sumerian
Ur
Translation
Traduction

description: Traduction Correspondence of the Kings of Ur 24: Ibbi-Sîn-Puzur-Numušda 1, version courte (3.1.20) Pascal Attinger, 2012, actualisé en 2019
New method for the quantum ground states in one dimension
Creators: name: Chung, S. G.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: A simple, general and practically exact method is developed to calculate the ground states of 1D macroscopic quantum systems with translational symmetry. Applied to the Hubbard model, a modest calculation reproduces the Bethe Ansatz results.