cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Unsupervised Graph Poisoning Attack via Contrastive Loss Back-propagation
Creators: name: Zhang, Sixiao
name: Chen, Hongxu
name: Sun, Xiangguo
name: Li, Yicong
name: Xu, Guandong
Publisher: name: arXiv
Year: 2022
Subjects: subject: Machine Learning (cs.LG)
subject: Information Retrieval (cs.IR)
subject: FOS: Computer and information sciences

description: Graph contrastive learning is the state-of-the-art unsupervised graph representation learning framework and has shown comparable performance with supervised approaches. However, evaluating whether the graph contrastive learning is robust to adversarial attacks is still an open problem because most existing graph adversarial attacks are supervised models, which means they heavily rely on labels and can only be used to evaluate the graph contrastive learning in a specific scenario. For unsupervised graph representation methods such as graph contrastive learning, it is difficult to acquire labels in real-world scenarios, making traditional supervised graph attack methods difficult to be applied to test their robustness. In this paper, we propose a novel unsupervised gradient-based adversarial attack that does not rely on labels for graph contrastive learning. We compute the gradients of the adjacency matrices of the two views and flip the edges with gradient ascent to maximize the contrastive loss. In this way, we can fully use multiple views generated by the graph contrastive learning models and pick the most informative edges without knowing their labels, and therefore can promisingly support our model adapted to more kinds of downstream tasks. Extensive experiments show that our attack outperforms unsupervised baseline attacks and has comparable performance with supervised attacks in multiple downstream tasks including node classification and link prediction. We further show that our attack can be transferred to other graph representation models as well.
Dimerization of pentanuclear clusters [Fe3Q(AsMe)(CO)9] (Q = Se, Te) as conversion pathway to novel cubane-like aggregates
Creators: name: Pushkarevsky, Nikolai A.
name: Konchenko, Sergei N.
name: Zabel, Manfred
name: Bodensteiner, Michael
name: Scheer, Manfred
Publisher: name: Universität Regensburg
Year: 2011
Subjects: subject: 540 Chemie

description: The first examples of carbonyl heterocubane-type clusters, [Fe4(μ3-Q)2(μ3-AsMe)2(CO)12] (2, Q = Se (a), Te (b)), which simultaneously contain elements of group 15 and 16, were obtained by thermolysis of [Fe3(μ3-Q)(μ3-AsMe)(CO)9] (1) in acetonitrile. The clusters 2 possess a cubic Fe4Q2As2 core with alternating Fe and Q/As atoms. The coordination environment of the Fe atoms is close to octahedral, and those of Q or As atoms are tetrahedral, which determines the distorted cubic cluster core geometry. The second main products of thermolysis are the clusters [Fe6(μ3-Q)(μ4-Q)(μ4-AsMe)2(CO)12] (3a,b), whose core contains double the elemental composition of the initial cluster 1. In the case of the Se-containing cluster two other minor products [Fe4(μ4-Se)(μ4-SeAsMe)(CO)12] (4) and [Fe3(μ3-AsMe)2(CO)9] (5) are formed. Based on the structures and properties of the products, a reaction route for the conversion of 1 into 2 is proposed, which includes the associative formation of the clusters 3 as intermediates, unlike the dissociative pathways previously known for the transformations of similar clusters of the type [Fe3Q2(CO)9].
Magnitude and sign control of lithography-induced uniaxial anisotropy in ultra-thin (Ga,Mn)As wires
Creators: name: Shiogai, Junichi
name: Schuh, Dieter
name: Wegscheider, Werner
name: Kohda, M.
name: Nitta, J.
name: Weiss, Dieter
Publisher: name: Universität Regensburg
Year: 2011
Subjects: subject: electron beam lithography, ferromagnetic materials, gallium arsenide, III-V semiconductors, magnetic anisotropy, magnetic semiconductors, manganese compounds, wires
subject: 530 Physik
subject: 75.30.Gw
subject: 75.50.Pp
subject: 81.05.Ea

description: We were able to control the magnitude and sign of the uniaxial anisotropy in 5-nm-thin (Ga,Mn)As wires by changing the crystallographic direction of the lithography-induced strain relaxation. The 1-μm-wide (Ga,Mn)As wires, oriented in [110] and [1math0] directions, were fabricated using electron beam lithography. Their magnetic anisotropies were studied by a coherent rotation method at temperatures between 4.5 and 75 K. Depending on the orientation of the wire, the additional uniaxial anisotropy observed along the axis of the 1-μm-wide samples either increased or decreased the total uniaxial anisotropy.
Spectroscopy of a Qubit Array via a Single Transmission Line
Creators: name: Jerger, M.
name: Poletto, S.
name: Macha, P.
name: Huebner, U.
name: Lukashenko, A.
name: Il'ichev, E.
name: Ustinov, A. V.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Instrumentation and Detectors (physics.ins-det)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Frequency-selective readout for superconducting qubits opens the way towards scaling qubit circuits up without increasing the number of measurement lines. Here we demonstrate the readout of an array of 7 flux qubits located on the same chip. Each qubit is placed near an individual lambda/4 resonator which, in turn, is coupled to a common microwave transmission line. We performed spectroscopy of all qubits and determined their parameters in a single measurement run.
description: 3 pages, 3 figures
Category-Association Based Similarity Matching for Novel Object Pick-and-Place Task
Creators: name: Chen, Hao
name: Kiyokawa, Takuya
name: Wan, Weiwei
name: Harada, Kensuke
Publisher: name: arXiv
Year: 2022
Subjects: subject: Robotics (cs.RO)
subject: Systems and Control (eess.SY)
subject: FOS: Computer and information sciences
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: Robotic pick-and-place has been researched for a long time to cope with uncertainty of novel objects and changeable environments. Past works mainly focus on learning-based methods to achieve high precision. However, they have difficulty being generalized for the limitation of specified training models. To break through this drawback of learning-based approaches, we introduce a new perspective of similarity matching between novel objects and a known database based on category-association to achieve pick-and-place tasks with high accuracy and stabilization. We calculate the category name similarity using word embedding to quantify the semantic similarity between the categories of known models and the target real-world objects. With a similar model identified by a similarity prediction function, we preplan a series of robust grasps and imitate them to plan new grasps on the real-world target object. We also propose a distance-based method to infer the in-hand posture of objects and adjust small rotations to achieve stable placements under uncertainty. Through a real-world robotic pick-and-place experiment with a dozen of in-category and out-of-category novel objects, our method achieved an average success rate of 90.6% and 75.9% respectively, validating the capacity of generalization to diverse objects.
description: Published by the IEEE Robotics and Automation Letters
The Importance of Multimodal Emotion Conditioning and Affect Consistency for Embodied Conversational Agents
Creators: name: Chang, Che-Jui
name: Sohn, Samuel S.
name: Zhang, Sen
name: Jayashankar, Rajath
name: Usman, Muhammad
name: Kapadia, Mubbasir
Publisher: name: arXiv
Year: 2023
Subjects: subject: Human-Computer Interaction (cs.HC)
subject: Artificial Intelligence (cs.AI)
subject: Graphics (cs.GR)
subject: FOS: Computer and information sciences

description: Previous studies regarding the perception of emotions for embodied virtual agents have shown the effectiveness of using virtual characters in conveying emotions through interactions with humans. However, creating an autonomous embodied conversational agent with expressive behaviors presents two major challenges. The first challenge is the difficulty of synthesizing the conversational behaviors for each modality that are as expressive as real human behaviors. The second challenge is that the affects are modeled independently, which makes it difficult to generate multimodal responses with consistent emotions across all modalities. In this work, we propose a conceptual framework, ACTOR (Affect-Consistent mulTimodal behaviOR generation), that aims to increase the perception of affects by generating multimodal behaviors conditioned on a consistent driving affect. We have conducted a user study with 199 participants to assess how the average person judges the affects perceived from multimodal behaviors that are consistent and inconsistent with respect to a driving affect. The result shows that among all model conditions, our affect-consistent framework receives the highest Likert scores for the perception of driving affects. Our statistical analysis suggests that making a modality affect-inconsistent significantly decreases the perception of driving affects. We also observe that multimodal behaviors conditioned on consistent affects are more expressive compared to behaviors with inconsistent affects. Therefore, we conclude that multimodal emotion conditioning and affect consistency are vital to enhancing the perception of affects for embodied conversational agents.
Installation of charging infrastructure for electric vehicles in multi-unit residential buildings in British Columbia
Creators: name: Lopez Behar, Diana
Publisher: name: University of British Columbia
Year: 2017

description: Electric Vehicles (EVs) contribute to the mitigation of climate change through reduced greenhouse gas emissions, when powering with sustainable sources of electricity. The province of British Columbia (BC) is an attractive location for EV deployment since most of its electricity is sourced from clean renewable energy sources. Due to their driving range and potential to reduce local emissions, EVs work well in urban contexts, where most residential buildings are located. As a result, residents from Multi-Unit Residential Buildings (MURBs) are among those interested in becoming EV owners, thus requiring access to charging infrastructure, especially overnight home charging, which is the preferred charging alternative. However, most residential buildings are not equipped with charging infrastructure and its installation can have numerous challenges that can turn into barriers. This thesis explores the implications, challenges and decision-making processes of EV charging infrastructure installation in MURBs to identify present and future barriers to infrastructure provision, as well as potential policy-driven interventions to address them. The methods used to conduct the research study include the utilization of conceptual frameworks and the application of systems thinking principles to map the interrelation and causalities of the problem domains as causal loop diagrams. A review of the literature identified the key problem domains. Policy recommendations were then classified based on each problem domain. First, financial or fiscal policy measures include creating incentives for EV owners and extending them to the building owners, as well as programs to incentivize and provide financial aid for building owners to develop building retrofit plans. Second, regulatory policy measures include revising the regulations and addressing the rights and obligations of the stakeholders, as well as making mandatory the installation of charging stations in new MURBs. Third, information and awareness policy measures include expanding the existing guidelines and informing the development of a long-term EV charging infrastructure plan. These policy recommendations are relevant to different stakeholders as they have the potential to inform the decisions and policy programs of the municipal and provincial government of BC, as well as other governmental and non-governmental agencies and associations.
Effect of Mammalian Tissue Source on the Molecular and Macroscopic Characteristics of UV-Cured Type I Collagen Hydrogel Networks
Creators: name: Brooker, Charles
name: Tronci, Giuseppe
Publisher: name: arXiv
Year: 2022
Subjects: subject: Tissues and Organs (q-bio.TO)
subject: FOS: Biological sciences

description: The tissue source of type I collagen is critical to ensure scalability and regulation-friendly clinical translation of new medical device prototypes. However, the selection of a commercial source of collagen that fulfils both aforementioned requirements and is compliant with new manufacturing routes is challenging. This study investigates the effect that type I collagen extracted from three different mammalian tissues has on the molecular and macroscopic characteristics of a new UV-cured collagen hydrogel. Pepsin-solubilised bovine atelocollagen (BA) and pepsin-solubilised porcine atelocollagen (PA) were selected as commercially available raw materials associated with varying safety risks and compared with in-house acid-extracted type I collagen from rat tails (CRT). All raw materials displayed the typical dichroic and electrophoretic characteristics of type I collagen, while significantly decreased lysine content was measured on samples of PA. Following covalent functionalisation with 4-vinylbenzyl chloride (4VBC), BA and CRT products generated comparable UV-cured hydrogels with significantly increased averaged gel content (G > 97 wt.%), while the porcine variants revealed the highest swelling ratio (SR = 2224 +/- 242 wt.%) and an order of magnitude reduction in compression modulus (Ec = 6 +/- 2 kPa). Collectively, these results support the use of bovine tissues as a chemically viable source of type I collagen for the realisation of UV-cured hydrogels with competitive mechanical properties and covalent network architectures.
description: Accepted in Prosthesis, 21 pages, 7 pages, 2 tables
Multiband strong-coupling superconductors with spontaneously broken time-reversal symmetry
Creators: name: Aase, Niels Henrik
name: Mæland, Kristian
name: Sudbø, Asle
Publisher: name: arXiv
Year: 2023
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We study superconducting three-band systems within strong-coupling Eliashberg theory. In particular, we search for phase-frustrated superconducting systems with spontaneous time-reversal symmetry breaking (TRSB) states. The emergence of TRSB states in multiband systems has so far been studied using microscopic weak-coupling BCS theory or more phenomenological effective field theories such as multi-component Ginzburg-Landau theories. For systems with three disjoint Fermi surfaces whose electrons experience interactions mediated by phonons, we present a microscopic analysis showing that TRSB states also exist within a strong-coupling microscopic theory. The systems we consider have sizable electron-phonon couplings, putting them into the strong-coupling regime. They are thus a fitting description for strong-coupling materials such as some of the iron pnictides. Moreover, as the TRSB states are challenging to find numerically, we calculate the free energy of multiband systems within strong-coupling theory and make explicit use of it to pin down the TRSB states' elusive nature. Since Eliashberg theory is well incorporated with first-principles calculations, our strong-coupling approach might help facilitate a more efficient search for candidate materials that can exhibit TRSB.
description: 15 pages, 6 figures
Automatic algorithm to obtain $v \sin i$ values via Fourier Transform in BeSOS database
Creators: name: Solar, Martín
name: Arcos, Catalina
name: Curé, Michel
name: Levenhagen, Ronaldo S.
name: Araya, Ignacio
Publisher: name: arXiv
Year: 2022
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Be stars are found to rotate close to their critical rotation and therefore they are considered as an important laboratory of study for stellar rotation. In this context, we obtain the projected rotational velocity of a sample of classical Be Southern stars in the BeSOS database via Fourier Transform in an automated way for several absorption lines at different epochs. A Gaussian profile is fitted to eight observed photospheric HeI lines in order to select automatically the spectral signal given by areas under the curve of 95.45%, 98.75% and 99.83% from the profile to obtain $v \sin i$ via Fourier Transform technique. The values obtained are in global agreement with the literature. Analysing only one line is not enough to set the $v \sin i$ value, depending on the line the value in most cases are underestimated with respect to $λ$4471. When gravity darkening effects are including, apparent values increases by $\sim10$%. The resolution of the instrument PUCHEROS used for BeSOS spectra ($R \sim 17\,000$) constrain a theoretical lower bound possible at $v \sin i \sim 100$ km s$^{-1}$. The procedure has limitations using a linear limb-darkening function with $\varepsilon = 0.6$ for classical Be stars rotating close to the break-up velocity without gravity-darkening corrections, which can't be negligible. Previous works measure $v \ sin i$ values using just one spectral line and here we demonstrate that with more lines the results can varies. This could be due to the photospheric distribution of atomic transitions on classical Be stars.
description: 14 pages, 10 figures, MNRAS, accepted
Click Chemistry Based Method for the Preparation of Maleinimide-Type Thiol-Reactive Labels
Creators: name: Link, Martin
name: Li, Xiaohua
name: Kleim, Jana
name: Wolfbeis, Otto S.
Publisher: name: Universität Regensburg
Year: 2010
Subjects: subject: Click chemistry; Fluorescent probes; Imaging agents; Proteins; Thiols
subject: 540 Chemie

description: Maleinimides are widely used to label proteins and to derivatize thiols. The so-called click reaction was shown to allow the efficient introduction of the maleinimido group into azido-modified fluorophores (benzoxazines) by reacting them with an alkyne-modified maleinimide to yield new thiol-reactive fluorescent labels 5–7. The reaction proceeds under mild experimental conditions and provides a new strategy with which to introduce the maleimide group, as exemplified here for fluorophores. Conceivably, it may be extended to radioactive, electro-active, isotopic, or spin labels. Previously reported methods for the formation of such maleinimides starting from open-ring precursors require rather harsh conditions. The new benzoxazines 5–7 are characterized by a fairly long and flexible linker between the chromophore and the maleinimide functional group, and their fluorescence can be photoexcited with diode lasers (which are preferred light sources in fluorometry). They were conjugated to: (a) the aminothiol cysteamine, (b) the peptide glutathione, and (c) to human serum albumin. The fluorescence of the phenoxazinone 5 is strongly solvatochromic, which suggests its use as a polarity-sensitive probe.
Chromogenic Sensing of Biogenic Amines Using a Chameleon Probe and the Red−Green−Blue Readout of Digital Camera Images
Creators: name: Steiner, Mark-Steven
name: Meier, Robert J.
name: Dürkop, Axel
name: Wolfbeis, Otto S.
Publisher: name: Universität Regensburg
Year: 2010
Subjects: subject: luminescence; nanoparticles; oxygen; sensor; upconversion
subject: 540 Chemie

description: We report on sensing spots containing an amine reactive chromogenic probe and a green fluorescent (amine insensitive) reference dye incorporated in a hydrogel matrix on a solid support. Such spots enable rapid and direct determination of primary amines and, especially, biogenic amines (BA). A distinct color change from blue to red occurs on dipping the test spots into a pH 9.0 sample containing primary amines. BAs can be determined in the concentration range from 0.01 to 10 mM within 15 min, enabling rapid, qualitative, and semiquantitative evaluation. In the “photographic” approach, the typically 4−7.5-fold increase in fluorescence intensity of the probe at 620 nm along with the constant green fluorescence at 515 nm of a reference dye are used for quantitation of BAs. The sensing spots are photoexcited with high-power 505 nm light-emitting diodes (LEDs) in a black box. A digital picture is acquired with a commercially available digital camera, and the color information is extracted via red−green−blue (RGB) readout. The ratio of the intensities of the red (signal) channel and the green (reference) channel yields pseudocolor pictures and calibration plots.
Structure-Sensitive Mechanism of Nanographene Failure
Creators: name: Sheka, Elena F.
name: Popova, Nadezhda A.
name: Popova, Vera A.
name: Nikitina, Ekaterina A.
name: Shaymardanova, Landysh H.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: The response of a nanographene sheet to external stresses is considered in terms of a mechanochemical reaction. The quantum chemical realization of the approach is based on a coordinate-of-reaction concept for the purpose of introducing a mechanochemical internal coordinate (MIC) that specifies a deformational mode. The related force of response is calculated as the energy gradient along the MIC, while the atomic configuration is optimized over all of the other coordinates under the MIC constant-pitch elongation. The approach is applied to the benzene molecule and (5, 5) nanographene. A drastic anisotropy in the microscopic behavior of both objects under elongation along a MIC has been observed when the MIC is oriented either along or normally to the C-C bonds chain. Both the anisotropy and high stiffness of the nanographene originate at the response of the benzenoid unit to stress.
description: 19 pages, 7 figures 1 table
Evidence for circadian influence on human slow wave sleep during daytime sleep episodes
Creators: name: Campbell, S. S.
name: Zulley, Jürgen
Publisher: name: Universität Regensburg
Year: 1989
Subjects: subject: 610 Medizin
subject: Adult
subject: Arousal
subject: Body Temperature Regulation
subject: Circadian Rhythm
subject: Electroencephalography
subject: Humans
subject: Sleep Stages
subject: Wakefulness

description: The occurrence of slow wave sleep within spontaneously initiated daytime sleep episodes was studied to examine hypothesized associations with prior wakefulness and circadian factors. There was a strong relationship between measures of slow wave sleep and the proximity of sleep episodes to the maximum of body core temperature. Those sleep episodes that began within 4 hours of the maximum in body core temperature contained significantly more slow wave sleep than did all other daytime sleep periods, approximating proportions typical of nocturnal sleep. Multiple regression analysis revealed no relationship between measures of slow wave sleep and prior wakefulness. These findings are consistent with an hypothesized approximately-12-hour rhythm in the occurrence of slow wave sleep and they underscore the influence imposed on human sleep by the endogenous circadian timing system.
An OrthoBoXY-Method for Various Alternative Box Geometries
Creators: name: Busch, Johanna
name: Paschek, Dietmar
Publisher: name: arXiv
Year: 2023
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We have shown in a recent contribution [J. Phys. Chem.B 127, 7983-7987 (2023)] that for molecular dynamics (MD) simulations of isotropic fluids based on orthorhombic periodic boundary conditions with "magic" box length ratios of $L_z/L_x\!=\!L_z/L_y\!=\!2.7933596497$, the computed self-diffusion coefficients $D_x$ and $D_y$ in $x$- and $y$-direction become system size independent. They thus represent the true self-diffusion coefficient $D_0\!=\!(D_x+D_y)/2$, while the shear viscosity can be determined from diffusion coefficients in $x$-, $y$-, and $z$-direction, using the expression $η\!=\!k_\mathrm{B}T\cdot 8.1711245653/[3πL_z(D_{x}+D_{y}-2D_z)]$. Here we present a more generalized version of this "OrthoBoXY"-approach, which can be applied to any orthorhombic MD box. We would like to test, whether it is possible to improve the efficiency of the approach by using a shape more akin to the cubic form, albeit with different box-length ratios $L_x/L_z\!\neq\! L_y/L_z$ and $L_x\!<\!L_y\!<\!L_z$. We use simulations of systems of 1536 TIP4P/2005 water molecules as a benchmark and explore different box-geometries to determine the influence of the box shape on the computed statistical uncertainties for $D_0$ and $η$. Moreover, another "magical" set of box-length ratios is discovered with $L_y/L_z\!=\!0.57804765578$ and $L_x/L_z\!=\!0.33413909235$, where the self-diffusion coefficient in $x$-direction becomes system size independent, such that $D_0\!=\!D_x$.
description: 7 pages, 4 figures. Corrected typos and errors and added an additional new equation (now eq 7). arXiv admin note: text overlap with arXiv:2307.01591
A survey of diffuse interstellar bands in the Andromeda galaxy: optical spectroscopy of M31 OB stars
Creators: name: Cordiner, Martin A.
name: Cox, Nick L. J.
name: Evans, Christopher J.
name: Trundle, Carrie
name: Smith, Keith T.
name: Sarre, Peter J.
name: Gordon, Karl D.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We present the largest sample to-date of intermediate-resolution blue-to-red optical spectra of B-type supergiants in M31 and undertake the first survey of diffuse interstellar bands (DIBs) in this galaxy. Spectral classifications, radial velocities and interstellar reddenings are presented for 34 stars in three regions of M31. Radial velocities and equivalent widths are given for the 5780 and 6283 DIBs towards 11 stars. Equivalent widths are also presented for the following DIBs detected in three sightlines in M31: 4428, 5705, 5780, 5797, 6203, 6269, 6283, 6379, 6613, 6660, and 6993. All of these M31 DIB carriers reside in clouds at radial velocities matching those of interstellar Na I and/or H I. The relationships between DIB equivalent widths and reddening (E(B-V)) are consistent with those observed in the local ISM of the Milky Way. Many of the observed sightlines show DIB strengths (per unit reddening) which lie at the upper end of the range of Galactic values. DIB strengths per unit reddening are found (with 68% confidence), to correlate with the interstellar UV radiation field strength. The strongest DIBs are observed where the interstellar UV flux is lowest. The mean Spitzer 8/24 micron emission ratio in our three fields is slightly lower than that measured in the Milky Way, but we identify no correlation between this ratio and the DIB strengths in M31. Interstellar oxygen abundances derived from the spectra of three M31 H II regions in one of the fields indicate that the average metallicity of the ISM in that region is 12 + log[O/H] = 8.54 +- 0.18, which is approximately equal to the value in the solar neighbourhood.
Singular perturbation analysis of a reduced model for collective motion: A renormalization group approach
Creators: name: Lee, Chiu Fan
Publisher: name: arXiv
Year: 2011
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Biological Physics (physics.bio-ph)
subject: FOS: Physical sciences

description: In a system of noisy self-propelled particles with interactions that favor directional alignment, collective motion will appear if the density of particles is beyond a critical density. Starting with a reduced model for collective motion, we determine how the critical density depends on the form of the initial perturbation. Specifically, we employ a renormalization-group improved perturbative method to analyze the model equations, and show analytically, up to first order in the perturbation parameter, how the critical density is modified by the strength of the initial angular perturbation in the system.
Dynamics of a quantum reference frame undergoing selective measurements and coherent interactions
Creators: name: Ahmadi, Mehdi
name: Jennings, David
name: Rudolph, Terry
Publisher: name: arXiv
Year: 2010
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We consider the dynamics of a quantum directional reference frame undergoing repeated interactions. We first describe how a precise sequence of measurement outcomes affects the reference frame, looking at both the case that the measurement record is averaged over and the case wherein it is retained. We find, in particular, that there is interesting dynamics in the latter situation which cannot be revealed by considering the averaged case. We then consider in detail how a sequence of rotationally invariant unitary interactions affects the reference frame, a situation which leads to quite different dynamics than the case of repeated measurements. We then consider strategies for correcting reference frame drift if we are given a set of particles with polarization opposite to the direction of drift. In particular, we find that by implementing a suitably chosen unitary interaction after every two measurements we can eliminate the rotational drift of the reference frame.
description: 9 pages, 5 figures
FAKTOR PENDUKUNG MENJADI SEORANG WIRAUSAHAWAN
Creators: name: RETNOWATI SATYANINGRUM
Publisher: name: Zenodo
Year: 2022
Subjects: entrepreneur, kewirausahaan

description: Kewiraswastaan atau Kewirausahaan adalah proses mengidentifikasi, mengembangkan, dan membawa visi ke dalam kehidupan. Visi tersebut bisa berupa ide inovatif, peluang, cara yang lebih baik dalam menjalankan sesuatu
description: -
The Magnetic Fields of the Quiet Sun
Creators: name: Almeida, J. Sanchez
name: Gonzalez, M. Martinez
Publisher: name: arXiv
Year: 2011
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: This work reviews our understanding of the magnetic fields observed in the quiet Sun. The subject has undergone a major change during the last decade (quiet revolution), and it will remain changing since the techniques of diagnostic employed so far are known to be severely biased. Keeping these caveats in mind, our work covers the main observational properties of the quiet Sun magnetic fields: magnetic field strengths, unsigned magnetic flux densities, magnetic field inclinations, as well as the temporal evolution on short time-scales (loop emergence), and long time-scales (solar cycle). We also summarize the main theoretical ideas put forward to explain the origin of the quiet Sun magnetism. A final prospective section points out various areas of solar physics where the quiet Sun magnetism may have an important physical role to play (chromospheric and coronal structure, solar wind acceleration, and solar elemental abundances).
description: Review talk presented to the 6th Solar Polarization Workshop held in Maui HI, USA, May-June 2010
Hubble Space Telescope Imaging and Spectral Analysis of Two Brown Dwarf Binaries at the L Dwarf/T Dwarf Transition
Creators: name: Burgasser, Adam J.
name: Gagliuffi, Daniella C. Bardalez
name: Gizis, John E.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We present a detailed examination of the brown dwarf multiples 2MASS J08503593+1057156 and 2MASS J17281150+3948593, both suspected of harboring components that straddle the L dwarf/T dwarf transition. Resolved photometry from Hubble Space Telescope/NICMOS show opposite trends in the relative colors of the components, with the secondary of 2MASS J0850+1057 being redder than its primary, while that of 2MASS J1728+3948 is bluer. We determine near-infrared component types by matching combined-light, near-infrared spectral data to binary templates, with component spectra scaled to resolved NICMOS and Kp photometry. Combinations of L7 + L6 for 2MASS J0850+1057 and L5 + L6.5 for 2MASS J1728+3948 are inferred. Remarkably, the primary of 2MASS J0850+1057 appears to have a later-type classification compared to its secondary, despite being 0.8-1.2 mag brighter in the near-infrared, while the primary of 2MASS J1728+3948 is unusually early for its combined-light optical classification. Comparison to absolute magnitude/spectral type trends also distinguishes these components, with 2MASS J0850+1057A being ~1 mag brighter and 2MASS J1728+3948A ~0.5 mag fainter than equivalently-classified field counterparts. We deduce that thick condensate clouds are likely responsible for the unusual properties of 2MASS J1728+3948A, while 2MASS J0850+1057A is either an inflated young brown dwarf or a tight unresolved binary, making it potentially part of a wide, low-mass, hierarchical quintuple system.
description: 17 pages, accepted for publication to AJ; spectral data are available at http://www.browndwarfs.org/spexprism
Selective picomolar detection of mercury(II) using optical sensors
Creators: name: Díez-Gil, César
name: Martínez, Rosario
name: Ratera, Imma
name: Hirsch, Thomas
name: Espinosa, Arturo
name: Tárraga, Alberto
name: Molina, Pedro
name: Wolfbeis, Otto S.
name: Veciana, Jaume
Publisher: name: Universität Regensburg
Year: 2011
Subjects: subject: 540 Chemie

description: The rational design of a mercury(II) ligand consisting in a 1-(4′-oxyphenyl)-4(1′-pyrenyl)-2,3-diaza-1,3-butadiene receptor unit, optimizes the sensitivity and reliability of a SPR sensor by the formation of a well packed SAM over the gold surface. SPR analysis allows detecting mercury(II) concentrations in aqueous systems in the picomolar range, meliorating on three orders of magnitude the EU mercury(II) detection limit in drinkable water.
Photonic architectures for ultrafast all-optical switching and retro-modulation
Creators: name: Born, Brandon
Publisher: name: University of British Columbia
Year: 2018

description: Optical communications is the backbone of the modern internet. However, the true potential of the deployed optical networks has not been reached due to a reliance on far slower electronic processing. The ultimate objective is a fully all-optical network, to circumvent electronic bottlenecks and allow for network transparency, but there are challenges to the realization of all-optical implementations in current fibre optic and emerging free-space optical (FSO) communication networks. This thesis introduces two photonic architectures to address these challenges. First, an all-optical switch (AOS) architecture is developed for implementation in fibre optic front-end systems, where all-optical switching is the fundamental building block of all-optical processing. The AOS architecture applies a nanophotonic superlens, in the form of a dielectric sphere, to form an intense non-evanescent near-subwavelength focus called a photonic nanojet. The photonic nanojet forms at the back surface of the sphere in a coating of semiconductor nanoparticles. The AOS architecture is refined using Drude theory to study the free-carrier dynamics within the semiconductor nanoparticles, as well as Mie theory and ray theory to optimize the photonic nanojet’s intensity. Experiments are conducted with both milli- and micro-scale spheres coated by Si, SiC, CdTe, InP, and CuO nanoparticles. The realized AOS architecture meets the ultimate goals of femtojoule switching energies and femtosecond switching times. Second, an all-optical retro-modulation (AORM) architecture is developed for implementation in FSO communication systems, for which there is keen interest to establish high-bandwidth aerial-ground links. All-optical retro-modulation, a novel method for passive FSO aerial-ground communication, is proposed for future laser-based links with satellites, unmanned aerial vehicles, and high-altitude platforms. The AORM architecture is implemented with high-refractive-index S-LAH79 hemispheres to realize effective retroreflection and an interior semiconductor thin film of CuO nanocrystals to realize ultrafast all-optical modulation. A detailed investigation is carried out on the bandstructure and ultrafast free-carrier dynamics of the CuO nanocrystals. The AORM architecture is fabricated and shown to meet the ultimate goal of multidirectional FSO communication at terabit-per-second data rates. Overall, the introduced AOS and AORM photonic architectures can lay the foundation for future all-optical networks.
Multifrequency VLBA study of the blazar S5 0716+714 during the active state in 2004 II. Large-scale jet kinematics and the comparison of the different methods of VLBI data imaging as applied to kinematic studies of AGN
Creators: name: Rastorgueva, Elizaveta A.
name: Wiik, Kaj J.
name: Bajkova, Anisa T.
name: Valtaoja, Esko
name: Takalo, Leo O.
name: Vetukhnovskaya, Yliya N.
name: Mahmud, Mehreen
Publisher: name: arXiv
Year: 2011
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We study the jet kinematics of the blazar S5 0716+714 during its active state in 2003-2004 with multi-epoch VLBI observations. Aims. We present a kinematic analysis of the large-scale (0-12 mas) jet of 0716+714, based on the results of six epochs of VLBA monitoring at 5 GHz. Additionally, we compare kinematic results obtained with two imaging methods based on different deconvolution algorithms. The blazar 0716+714 has a diffuse large-scale jet and a very faint bright compact core. Experiments with simulated data showed that the conventional data reduction procedure based on the CLEAN deconvolution algorithm does not perform well in restoring this type of structure. This might be the reason why previous kinematic studies of this source yielded ambiguous results. In order to obtain accurate kinematics of this source, we independently applied two imaging techniques to the raw data: the conventional method, based on difference mapping, which uses CLEAN deconvolution, and the generalized maximum entropy method (GMEM) realized in the VLBImager package developed at the Pulkovo Observatory in Russia. The results of both methods give us a consistent kinematic scenario: the large-scale jet of 0716+714 is diffuse and stationary. Differences between the inner (0-1 mas) and outer (1-12 mas) regions of the jet in brightness and velocity of the components could be explained by the bending of the jet, which causes the angle between the jet direction and the line of sight to change from ~5 deg to ~11 deg. For the source 0716+714 both methods worked at the limit of their capability.
description: 13 pages, 7 figures. Accepted for publication in A&A, 2011
Interpretability in Convolutional Neural Networks for Building Damage Classification in Satellite Imagery
Creators: name: Chen, Thomas Y.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Artificial Intelligence (cs.AI)
subject: Machine Learning (cs.LG)
subject: Geophysics (physics.geo-ph)
subject: FOS: Computer and information sciences
subject: FOS: Physical sciences
subject: I.4.9

description: Natural disasters ravage the world's cities, valleys, and shores on a regular basis. Deploying precise and efficient computational mechanisms for assessing infrastructure damage is essential to channel resources and minimize the loss of life. Using a dataset that includes labeled pre- and post- disaster satellite imagery, we take a machine learning-based remote sensing approach and train multiple convolutional neural networks (CNNs) to assess building damage on a per-building basis. We present a novel methodology of interpretable deep learning that seeks to explicitly investigate the most useful modalities of information in the training data to create an accurate classification model. We also investigate which loss functions best optimize these models. Our findings include that ordinal-cross entropy loss is the most optimal criterion for optimization to use and that including the type of disaster that caused the damage in combination with pre- and post-disaster training data most accurately predicts the level of damage caused. Further, we make progress in the qualitative representation of which parts of the images that the model is using to predict damage levels, through gradient-weighted class activation mapping (Grad-CAM). Our research seeks to computationally contribute to aiding in this ongoing and growing humanitarian crisis, heightened by anthropogenic climate change.
description: 8 pages; presented as Spotlight Talk at NeurIPS - Tackling Climate Change with Machine Learning workshop 2020
Luminescent Sensing of Oxygen Using a Quenchable Probe and Upconverting Nanoparticles
Creators: name: Wolfbeis, Otto S.
name: Achatz, Daniela E.
name: Meier, Robert J.
name: Fischer, Lorenz H.
Publisher: name: Universität Regensburg
Year: 2011
Subjects: subject: luminescence; nanoparticles; oxygen; sensor; upconversion
subject: 540 Chemie

description: Turned off by oxygen: Luminescent upconverting nanoparticles (UCNPs) of the type NaYF4:Yb,Tm are employed in an entirely new type of optical sensor for oxygen (see picture). Upon laser excitation at 980 nm, these UCNPs act as nanolamps, the blue emission of which is used to photoexcite an iridium complex dissolved in ethyl cellulose. Its green emission, in turn, is dynamically and fully reversibly quenched by molecular oxygen.
MCA Based Performance Evaluation of Project Selection
Creators: name: Bakshi, Tuli
name: Sarkar, Bijan
Publisher: name: arXiv
Year: 2011
Subjects: subject: Software Engineering (cs.SE)
subject: FOS: Computer and information sciences

description: Multi-criteria decision support systems are used in various fields of human activities. In every alternative multi-criteria decision making problem can be represented by a set of properties or constraints. The properties can be qualitative & quantitative. For measurement of these properties, there are different unit, as well as there are different optimization techniques. Depending upon the desired goal, the normalization aims for obtaining reference scales of values of these properties. This paper deals with a new additive ratio assessment method. In order to make the appropriate decision and to make a proper comparison among the available alternatives Analytic Hierarchy Process (AHP) and ARAS have been used. The uses of AHP is for analysis the structure of the project selection problem and to assign the weights of the properties and the ARAS method is used to obtain the final ranking and select the best one among the projects. To illustrate the above mention methods survey data on the expansion of optical fibre for a telecommunication sector is used. The decision maker can also used different weight combination in the decision making process according to the demand of the system.
description: 9 Pages,1 Figure, 7 Tables
Risk perception and foreign exchange risk management in microfinance
Creators: name: Priberny, Christopher
name: Dorfleitner, Gregor
Publisher: name: Universität Regensburg
Year: 2013
Subjects: subject: sustainable finance, microfinance, FX risk, risk management, survey
subject: 330 Wirtschaft
subject: G21

description: We study the perception of risks in the funding of microfinance institutions. A survey addressed to microfinance institutions and their funding organizations reveals that several risk types, among them foreign exchange (FX) risk, are not considered to be as important as reported in the relevant literature. We obtain further insights into the FX risk management of microfinance actors and reveal that many FX risk mitigation strategies and hedging tools are rarely used in practice.
Hybrid Quantum Machine Learning Assisted Classification of COVID-19 from Computed Tomography Scans
Creators: name: Sünkel, Leo
name: Martyniuk, Darya
name: Reichwald, Julia J.
name: Morariu, Andrei
name: Seggoju, Raja Havish
name: Altmann, Philipp
name: Roch, Christoph
name: Paschke, Adrian
Publisher: name: arXiv
Year: 2023
Subjects: subject: Quantum Physics (quant-ph)
subject: Image and Video Processing (eess.IV)
subject: FOS: Physical sciences
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: Practical quantum computing (QC) is still in its infancy and problems considered are usually fairly small, especially in quantum machine learning when compared to its classical counterpart. Image processing applications in particular require models that are able to handle a large amount of features, and while classical approaches can easily tackle this, it is a major challenge and a cause for harsh restrictions in contemporary QC. In this paper, we apply a hybrid quantum machine learning approach to a practically relevant problem with real world-data. That is, we apply hybrid quantum transfer learning to an image processing task in the field of medical image processing. More specifically, we classify large CT-scans of the lung into COVID-19, CAP, or Normal. We discuss quantum image embedding as well as hybrid quantum machine learning and evaluate several approaches to quantum transfer learning with various quantum circuits and embedding techniques.
Self-similar sequence transformation for critical exponents
Creators: name: Yukalov, V. I.
name: Yukalova, E. P.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: Self-similar sequence transformation is an original type of nonlinear sequence transformations allowing for defining effective limits of asymptotic sequences. The method of self-similar factor transformations is shown to be regular. This method is applied for calculating the critical exponents of the $O(N)$-symmetric $φ^4$ theory in three dimensions by summing asymptotic $\varepsilon$ expansions. It is shown that this method is straightforward and essentially simpler than other summation techniques involving complicated numerical calculations, while enjoying comparable accuracy.
description: Latex file, 14 pages, 8 tables
Circannual variation in the expression of beta 2-adrenoceptors on human peripheral mononuclear leukocytes (MNLs)
Creators: name: Haen, Ekkehard
name: Langenmayer, I.
name: Pangerl, A.
name: Liebl, B.
name: Remien, J.
Publisher: name: Universität Regensburg
Year: 1988
Subjects: subject: 610 Medizin
subject: Adult
subject: Asthma/blood
subject: Circadian Rhythm
subject: Humans
subject: Hypertension/blood
subject: Leukocytes, Mononuclear/metabolism
subject: Male
subject: Periodicity
subject: Radioligand Assay
subject: Receptors, Adrenergic, beta/metabolism

description: Peripheral mononuclear leukocytes (MNLs) are widely used as a tissue model in studies of beta-adrenoceptor disturbances in hypertension and asthmatic diseases. The beta 2-adrenoceptor density (Bmax), however, depends not only on the gender of the person under study and on the time of day the blood specimens are obtained. Evidence is now reported for a circannual variation in the expression of beta 2-adrenoceptor sites on peripheral MNLs. In male volunteers the 24-h mean was found to be highest in the men studied in April/May (1135 +/- 10 sites/cell) and decreased to 891 +/- 16 sites/cell in August and to 712 +r90 sites/cell in December (means +/- SE, P less than 0.01 April/May compared to December). Concomitantly the circadian amplitude increased from 17.3% +/- 6.4% of 24-h mean in April/May to 28.2% +/- 1.4% of 24-h mean in August and to 34.2% +/- 4.2% of 24-h mean in December (means +/- SE, P less than 0.05, April/May compared to December). The circadian acrophase remained constant (190 degrees +/- 30 degrees equivalent to 12 h 40 min +/- 2 h 00 min, means +/- SE).