cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Local pulse wave velocity detection over an arterial segment using photoplethysmography
Creators: name: Wenngren, Wilhelm Sven Ingemar
Publisher: name: University of British Columbia
Year: 2017

description: The goal of this thesis is to determine the validity of using photoplethysmography (the detection of changes of blood volume using light) to measure pulse wave velocity as part of a continuous and non-disruptive blood pressure monitor. There has been a limited advancement over the years in technologies to monitor personal blood pressure, which have rendered at-home monitoring still relatively intrusive. The main method for at-home blood pressure monitoring is the use of an inflating cuff that obstructs the artery to detect pressure. This system suffers from inherit drawbacks, such as limitations on recording accuracy if insufficient time has passed between samples and the restrictive nature of the cuff which can induce pain on a user. An alternative device that can monitor continuously would thus benefit people who are sensitive or need 24-hour monitoring. Ideally this would be a system that can be worn without discomfort and does not interfere with the user in any way. The ideal device would also allow continuous blood pressure monitoring throughout the cardiac cycle, independent of the level of physical activity of the user. Furthermore, this type of device would allow athletes to measure blood pressure during activity. To this end, a model is developed to describe blood pressure by measuring the arterial diameter on the radial artery and the pulse wave velocity (PWV) through it. Research suggests that these two metrics, along with the elasticity of an artery, can be used as a means to measure blood pressure non-invasively. This thesis focuses on the measurement of pulse wave velocity. The system design, including the hardware, is covered. The analysis techniques used to obtain raw signals, as well as the methods used to determine the PWV, will be discussed. The measurement location is described in detail. The results are shown to be comparable to values found in literature. However, due to lack of comparable measurement techniques, no direct comparisons between methods could be performed.
Observational hints on the Big Bounce
Creators: name: Mielczarek, Jakub
name: Kamionka, Michal
name: Kurek, Aleksandra
name: Szydlowski, Marek
Publisher: name: arXiv
Year: 2010
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In this paper we study possible observational consequences of the bouncing cosmology. We consider a model where a phase of inflation is preceded by a cosmic bounce. While we consider in this paper only that the bounce is due to loop quantum gravity, most of the results presented here can be applied for different bouncing cosmologies. We concentrate on the scenario where the scalar field, as the result of contraction of the universe, is driven from the bottom of the potential well. The field is amplified, and finally the phase of the standard slow-roll inflation is realized. Such an evolution modifies the standard inflationary spectrum of perturbations by the additional oscillations and damping on the large scales. We extract the parameters of the model from the observations of the cosmic microwave background radiation. In particular, the value of inflaton mass is equal to $m=(2.6 \pm 0.6) \cdot 10^{13}$ GeV. In our considerations we base on the seven years of observations made by the WMAP satellite. We propose the new observational consistency check for the phase of slow-roll inflation. We investigate the conditions which have to be fulfilled to make the observations of the Big Bounce effects possible. We translate them to the requirements on the parameters of the model and then put the observational constraints on the model. Based on assumption usually made in loop quantum cosmology, the Barbero-Immirzi parameter was shown to be constrained by $γ<1100$ from the cosmological observations. We have compared the Big Bounce model with the standard Big Bang scenario and showed that the present observational data is not informative enough to distinguish these models.
description: 25 pages, 8 figures, JHEP3.cls
Radio lobes and X-ray hot spots in the microquasar S26
Creators: name: Soria, Roberto
name: Pakull, Manfred W.
name: Broderick, Jess W.
name: Corbel, Stephane
name: Motch, Christian
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We have studied the structure and energetics of the powerful microquasar/shock-ionized nebula S26 in NGC 7793, with particular focus on its radio and X-ray properties. Using the Australia Telescope Compact Array, we have resolved for the first time the radio lobe structure and mapped the spectral index of the radio cocoon. The steep spectral index of the radio lobes is consistent with optically-thin synchrotron emission; outside the lobes, the spectral index is flatter, suggesting an additional contribution from free-free emission, and perhaps ongoing ejections near the core. The radio core is not detected, while the X-ray core has a 0.3-8 keV luminosity ~6 x 10^{36} erg/s. The size of the radio cocoon matches that seen in the optical emission lines and diffuse soft X-ray emission. The total 5.5-GHz flux of cocoon and lobes is ~2.1 mJy, which at the assumed distance of 3.9 Mpc corresponds to about 3 times the luminosity of Cas A. The total 9.0-GHz flux is ~1.6 mJy. The X-ray hot spots (combined 0.3-8 keV luminosity ~2 x 10^{37} erg/s) are located ~20 pc outwards of the radio hot spots (ie, downstream along the jet direction), consistent with a different physical origin of X-ray and radio emission (thermal-plasma and synchrotron, respectively). The total particle energy in the bubble is ~10^{53} erg: from the observed radio flux, we estimate that only about a few 10^{50} erg are stored in the relativistic electrons; the rest is in protons, nuclei and non-relativistic electrons. The X-ray-emitting component of the gas in the hot spots contains ~10^{51} erg, and ~10^{52} erg over the whole cocoon. We suggest that S26 provides a clue to understand how the ambient medium is heated by the mechanical power of a black hole near its Eddington accretion rate.
description: Accepted by MNRAS on 2010 July 12. Twelve pages, 8 figures, size = 1.3 MB. Contact the authors for higher-res figures
Heating of the Solar Chromosphere and Corona by Alfven Wave Turbulence
Creators: name: van Ballegooijen, A. A.
name: Asgari-Targhi, M.
name: Cranmer, S. R.
name: DeLuca, E. E.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: A three-dimensional MHD model for the propagation and dissipation of Alfven waves in a coronal loop is developed. The model includes the lower atmospheres at the two ends of the loop. The waves originate on small spatial scales (less than 100 km) inside the kilogauss flux elements in the photosphere. The model describes the nonlinear interactions between Alfven waves using the reduced MHD approximation. The increase of Alfven speed with height in the chromosphere and transition region (TR) causes strong wave reflection, which leads to counter-propagating waves and turbulence in the photospheric and chromospheric parts of the flux tube. Part of the wave energy is transmitted through the TR and produces turbulence in the corona. We find that the hot coronal loops typically found in active regions can be explained in terms of Alfven wave turbulence, provided the small-scale footpoint motions have velocities of 1-2 km/s and time scales of 60-200 s. The heating rate per unit volume in the chromosphere is 2 to 3 orders of magnitude larger than that in the corona. We construct a series of models with different values of the model parameters, and find that the coronal heating rate increases with coronal field strength and decreases with loop length. We conclude that coronal loops and the underlying chromosphere may both be heated by Alfvenic turbulence.
description: 28 pages (emulateapj style, 13 figures, 3 tables), ApJ, in press
Horses (Equus caballus) use human local enhancement cues and adjust to human attention
Creators: name: Krueger, Konstanze
name: Flauger, Birgit
name: Farmer, Kate
name: Maros, Katalin
Publisher: name: Universität Regensburg
Year: 2010
Subjects: subject: human-horse interaction, horse, attention-reading, position, familiarity
subject: 590 Tiere (Zoologie)

description: This study evaluates the horse (Equus caballus) use of human local enhancement cues and reaction to human attention when making feeding decisions. The superior performance of dogs in observing human states of attention suggests this ability evolved with domestication. However, some species show an improved ability to read human cues through socialization and training. We observed 60 horses approach a bucket with feed in a three-way object choice task when confronted with a) an unfamiliar or b) a familiar person in 4 different situations: 1) squatting behind the bucket, facing the horse (2) standing behind the bucket, facing the horse (3) standing behind the bucket in a back-turned position, gazing away from the horse and (4) standing a few meters from the bucket in a distant, back-turned position, again gazing away from the horse. Additionally, postures 1 and 2 were tested both with the person looking permanently at the horse, and with the person alternating their gaze between the horse and the bucket. When the person remained behind the correct bucket it was chosen significantly above chance. However, when the test person was turned and distant from the buckets, the horses’ performance deteriorated. In the turned person situations the horses approached a familiar person and walked towards their focus of attention significantly more often than with an unfamiliar person. Additionally, in the squatting and standing person situations, some horses approached the person before approaching the correct bucket. This happened more with a familiar person. We therefore conclude that horses can use humans as a local enhancement cue independently of their body posture or gaze consistency when the persons remain close to the food source, and that horses seem to orientate on the attention of familiar more than of unfamiliar persons. We suggest that socialization and training improve the ability of horses to read human cues.
Hidden Conformal Symmetry of Extremal Kerr-Bolt Spacetimes
Creators: name: Setare, M. R.
name: Kamali, V.
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We show that extremal Kerr-Bolt spacetimes have a hidden conformal symmetry. In this regard, we consider the wave equation of a massless scalar field propagating in extremal Kerr-Bolt spacetimes and find in the "near region", the wave equation in extremal limit can be written in terms of the $SL(2,R)$ quadratic Casimir. Moreover, we obtain the microscopic entropy of the extremal Kerr-Bolt spacetimes also we calculate the correlation function of a near-region scalar field and find perfect agreement with the dual 2D CFT.
description: 13 pages
Исследовательская программа: продолжение направления по Д.Г. Павлову в контексте Сфирали и H₃
Creators: name: Басаргин, Олег Сергеевич
Publisher: name: Zenodo
Year: 2025

description: Исследование посвящено построению и анализу фазовой геометрии пространства тройных чисел H₃ с кубической метрикой. Введена структура вложенных фаз — модуль r, бингл a и трингл b, формализованная через обобщённую экспоненту h = r ⋅ exp(Ia ⋅ exp(Jb)). Предложены операторы фазового действия I, J, описана интерференция фазовых траекторий и её когерентные формы. Рассмотрены прикладные аспекты: фазовая память, временные кристаллы и квантоподобные состояния. Модель H₃ интерпретируется как реализация Сфирали в трёхмерной фазовой топологии и предоставляет основу для нелинейной динамики в биологических, когнитивных и квантовых системах.

Ключевые слова: H₃, тройные числа, фазовая геометрия, бингл, трингл, кубическая метрика, фазовая память, временные кристаллы, квантовые аналоги, Сфираль, фазовая интерференция, фазовая логика
Affine Metric Geometry and Weak Orthogonal Groups
Creators: name: Havlicek, Hans
Publisher: name: arXiv
Year: 2023
Subjects: subject: Metric Geometry (math.MG)
subject: FOS: Mathematics
subject: 51F25 15A63

description: By following the ideas underpinning the well-established ``homogeneous model'' of an $n$-dimensional Euclidean space, we investigate whether the motion group or the weak motion group of an $n$-dimensional affine metric space on a vector space $V$ over an arbitrary field admits a specific faithful linear representation as weak orthogonal group of an $(n+1)$-dimensional metric vector space. Apart from a few exceptions, such a representation exists precisely when the metric structure on $V$ is given by a quadratic form with a non-degenerate polar form.
Principles for a democratically legitimate digitalisation
Creators: name: LORD, CHRISTOPHER
Publisher: name: Zenodo
Year: 2025
Subjects: digitalisation
legitimacy
democracy
deliberation
representation

description: This paper develops principles for a democratically legitimate form of digitalisation. It goes further than a need for an ethics of digitalisation. Ethics is a relationship between all persons. Democratic legitimacy is a relationship between citizens who share a democracy and, therefore, elect governments and make laws together.

Digital technologies have become a part of the infrastructure of contemporary democracies. They are a part of how parties, parliaments and publics debate, deliberate and communicate; how they form opinions; and how they give and demand accounts and justifications needed for public control. Digital technologies have transformed how governments and representatives contest elections; how they structure voter choice; how they compete; how they reach out to different pools of voters in the hope of aggregating them into winning electoral coalitions.

Standards of democratic legitimacy are not just important for those who regulate digital technologies. They also need to answer further questions. First what should consumers who are also citizens demand of social media and digital platforms? When should they complain, feel outraged, question the reputation or credibility of providers; or, where it is possible, take their custom elsewhere? Second what norms should providers internalise and enforce upon themselves if we are to believe them when they claim to contribute to democracy? Third where are democracies justified in demanding autonomy and non-interference by outsiders: both in any substantive rules democracies choose to regulate digitalisation and in the procedures they use to define the do’s and don’ts of digital governance?
Social feeding decisions in horses (Equus caballus)
Creators: name: Krueger, Konstanze
name: Flauger, Birgit
Publisher: name: Universität Regensburg
Year: 2008
Subjects: subject: Feeding decision; horse; rank; social behaviour.
subject: 590 Tiere (Zoologie)

description: Like many other herbivores, in a natural environment equids feed on rather evenly distributed resources. However, the vegetation in their vast habitats constantly changes. If food is plentiful only little competition occurs over food, and in non-competitive situations domestic horses tend to return to the same feeding site until it is overgrazed. In contrast, they compete over limited food for which the social status of the individuals appears to be important. Especially in ruminants several studies have proved an influence of social organisations, rank, sex and the depletion of feeding sites on the feeding behaviour of individuals. However, it is not yet understood whether and how social aspects affect horses´ feeding decisions. Curiosity about the influence of social rank on the horses´ feeding decisions between two, equally with high-quality surplus food filled buckets placed in different social feeding conditions, led us to create the test below. The observer horses were alternately tested with a dominant and a subordinate demonstrator placed in one of three different positions. We conclude that domestic horses use social cognition and strategic decision making in order to decide where to feed in a social feeding situation. When possible they tend to return to the same, continuously supplied feeding site and switch to an “avoidance tendency” in the presence of dominant horses or when another horse is already feeding there. Thus, the social rank and the position of conspecifics affect the feeding strategy of horses.
Structure and electronic properties of SiO₂/Si multilayer superlattices: Si K edge and L₃,₂ edge x-ray absorption fine structure study
Creators: name: Sammynaiken, R.
name: Naftel, S. J
name: Sham, T. K.
name: Cheah, K. W.
name: Averboukh, B.
name: Huber, Rupert
name: Shen, Y. R.
name: Qin, G. G.
name: Ma, Z. C.
name: Zong, W. H.
Publisher: name: Universität Regensburg
Year: 2002
Subjects: subject: 530 Physik

description: We report an x-ray absorption fine structure study at the Si K and L3,2 edges of a series of Si/SiO2 superlattices (SL). The SL system comprises four periods of elemental silicon with a spacing of 1, 1.4, 2.2, and 2.6 nm sandwiched by a 1.5 nm silicon oxide and capped by a 3 nm silicon oxide layer. These systems exhibit electroluminescence and photoluminescence. X-ray absorption near edge structure (XANES) at both the Si K and L3,2 edge confirms that the Si layers are amorphous. Polarization dependent measurement at the Si K edge reveals that a distinct Si/SiO2 interface exists with strong Si–O bonding oriented preferentially closer to the surface normal. High resolution XANES at the Si L3,2 edge shows a noticeable blueshift of the edge threshold as the lattice spacing decreases, in good accord with quantum confinement. The results and their implications for the origin (quantum confinement and interface/oxide defects) of luminescence in these superlattice systems are discussed.
Field-resolved detection of phase-locked infrared transients from a compact Er:fiber system tunable between 55 and 107 THz
Creators: name: Sell, A.
name: Scheu, R.
name: Leitenstorfer, A.
name: Huber, Rupert
Publisher: name: Universität Regensburg
Year: 2008
Subjects: subject: 530 Physik

description: We demonstrate phase-stable generation and ultrabroadband electro-optic detection of few-cycle multi-terahertz transients tunable from 55 to 107 THz based on a versatile telecom compatible three-branch Er:fiber laser system. Difference frequency mixing of two laser pulse trains at the full repetition rate of 49 MHz provides passively phase-locked multi-terahertz transients with peak fields of 69 kV/cm and average powers of up to 1.4 mW. 8 fs gating pulses from the third laser port allow for field-sensitive sampling throughout the midinfrared with a signal to noise ratio of up to 10⁴ Hz¹/². A leadoff application in trace gas detection is discussed.
description: » This publication has been selected for the Virtual Journal of Ultrafast Science
Polarization-dependent ponderomotive gradient force in a standing wave
Creators: name: Smorenburg, P. W.
name: Kanters, J. H. M.
name: Lassise, A.
name: Brussaard, G. J. H.
name: Kamp, L. P. J.
name: Luiten, O. J.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Classical Physics (physics.class-ph)
subject: FOS: Physical sciences

description: The ponderomotive force is derived for a relativistic charged particle entering an electromagnetic standing wave with a general three-dimensional field distribution and a nonrelativistic intensity, using a perturbation expansion method. It is shown that the well-known ponderomotive gradient force expression does not hold for this situation. The modified expression is still of simple gradient form, but contains additional polarization-dependent terms. These terms arise because the relativistic translational velocity induces a quiver motion in the direction of the magnetic force, which is the direction of large field gradients. Oscillation of the Lorentz factor effectively doubles this magnetic contribution. The derived ponderomotive force generalizes the polarization-dependent electron motion in a standing wave obtained earlier [A.E. Kaplan and A.L. Pokrovsky, Phys. Rev. Lett. $\bm{95}$, 053601 (2005)]. Comparison with simulations in the case of a realistic, non-idealized, three-dimensional field configuration confirms the general validity of the analytical results.
description: 13 pages, 4 figures
Spatial data integration and harmonization in the Adriatic Sea – how to make data FAIR for habitat, geological mapping and process modeling - archive
Creators: name: Known, User
Publisher: name: Zenodo
Year: 2021

description: Supplementary data of the paper "Spatial data integration and harmonization in the Adriatic Sea – how to make data FAIR (Findable, Accessible Interoperable and Researchable) for habitat, geological mapping and process modeling" Oceanologia 2021
description: Research Object in rohub2020: https://w3id.org/ro-id/0c4f6c48-3fdf-47de-90c9-805928b0972f
Sex-differences in respiratory mechanics during exercise in healthy aging
Creators: name: Molgat-Seon, Yannick
Publisher: name: University of British Columbia
Year: 2017

description: Purpose: Three studies were performed in order to comprehensively examine the combined effects of healthy aging and biological sex on respiratory mechanics and the perception of dyspnea during exercise in healthy adults. Methods: Study #1 (Chapter 2) investigated the mechanical ventilatory and sensory responses to incremental exercise in a group of younger men and women (20-30 years old), and older men and women (60-80 years old). Study #2 (Chapter 3) examined inspiratory muscle recruitment patterns during incremental exercise in a group of younger men and women (20-30 years old), and older men and women (60-80 years old). Study #3 (Chapter 4) assessed whether experimentally manipulating the magnitude of mechanical ventilatory constraint during moderate-intensity exercise would alter the perception of dyspnea in a group of older men and women. Conclusions: Healthy aging and biological sex independently increase the magnitude of ventilatory constraint during exercise in healthy adults. Specifically, older individuals and women have a higher work of breathing for a given minute ventilation, and a higher propensity towards expiratory flow limitation during exercise than men and younger individuals, respectively. Additionally, older women have a higher perception of dyspnea during exercise than older men, which could be explained by the combined effects of age and sex on mechanical ventilatory constraint during exercise (Study #1). Healthy aging and biological sex also independently affect the pattern of inspiratory muscle recruitment during exercise, where older individuals and women rely on extra-diaphragmatic inspiratory muscles to a greater extent than older individuals and women, respectively (Study #2). Despite these differences in respiratory mechanics, acutely manipulating the magnitude of mechanical ventilatory constraint during moderate-intensity exercise did not have an effect of the perception of dyspnea (Study #3). Collectively, the results of this thesis suggest that sex-differences in respiratory mechanics during exercise persist throughout the healthy aging process, but do not contribute to the increased sensations of dyspnea observed in healthy older women relative to healthy older men.
Fitting the integrated Spectral Energy Distributions of Galaxies
Creators: name: Walcher, C. J.
name: Groves, B.
name: Budavari, T.
name: Dale, D.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: Fitting the spectral energy distributions (SEDs) of galaxies is an almost universally used technique that has matured significantly in the last decade. Model predictions and fitting procedures have improved significantly over this time, attempting to keep up with the vastly increased volume and quality of available data. We review here the field of SED fitting, describing the modelling of ultraviolet to infrared galaxy SEDs, the creation of multiwavelength data sets, and the methods used to fit model SEDs to observed galaxy data sets. We touch upon the achievements and challenges in the major ingredients of SED fitting, with a special emphasis on describing the interplay between the quality of the available data, the quality of the available models, and the best fitting technique to use in order to obtain a realistic measurement as well as realistic uncertainties. We conclude that SED fitting can be used effectively to derive a range of physical properties of galaxies, such as redshift, stellar masses, star formation rates, dust masses, and metallicities, with care taken not to over-interpret the available data. Yet there still exist many issues such as estimating the age of the oldest stars in a galaxy, finer details ofdust properties and dust-star geometry, and the influences of poorly understood, luminous stellar types and phases. The challenge for the coming years will be to improve both the models and the observational data sets to resolve these uncertainties. The present review will be made available on an interactive, moderated web page (sedfitting.org), where the community can access and change the text. The intention is to expand the text and keep it up to date over the coming years.
description: 54 pages, 26 figures, Accepted for publication in Astrophysics & Space Science
Synthesis of a single cycle of light with compact erbium-doped fibre technology
Creators: name: Krauss, G.
name: Lohss, S.
name: Hanke, T.
name: Sell, A.
name: Eggert, S.
name: Huber, Rupert
name: Leitenstorfer, A.
Publisher: name: Universität Regensburg
Year: 2010
Subjects: subject: 530 Physik

description: The advent of self-referenced optical frequency combs1, 2 has sparked the development of novel areas in ultrafast sciences such as attosecond technology3, 4 and the synthesis of arbitrary optical waveforms5, 6. Few-cycle light pulses are key to these time-domain applications, driving a quest for reliable, stable and cost-efficient mode-locked laser sources with ultrahigh spectral bandwidth. Here, we present a set-up based entirely on compact erbium-doped fibre technology, which produces single cycles of light. The pulse duration of 4.3 fs is close to the shortest possible value for a data bit of information transmitted in the near-infrared regime. These results demonstrate that fundamental limits for optical telecommunications are accessible with existing fibre technology and standard free-space components.
description: » This publication has been selected for the Virtual Journal of Ultrafast Science
Dynamics of a qubit coupled to a dissipative nonlinear quantum oscillator: An effective-bath approach
Creators: name: Vierheilig, Carmen
name: Bercioux, Dario
name: Grifoni, Milena
Publisher: name: Universität Regensburg
Year: 2011
Subjects: subject: 530 Physik

description: We consider a qubit coupled to a nonlinear quantum oscillator, the latter coupled to an Ohmic bath, and investigate the qubit dynamics. This composed system can be mapped onto that of a qubit coupled to an effective bath. An approximate mapping procedure to determine the spectral density of the effective bath is given. Specifically, within a linear response approximation the effective spectral density is given by knowledge of the linear susceptibility of the nonlinear quantum oscillator. To determine the actual form of the susceptibility, we consider its periodically driven counterpart, which is the problem of the quantum Duffing oscillator within linear response theory in the driving amplitude. Knowing the effective spectral density, the qubit dynamics is investigated. In particular, an analytic formula for the qubit’s population difference is derived. Within the regime of validity of our theory, a very good agreement is found with predictions obtained from a Bloch-Redfield master equation approach applied to the composite qubit-nonlinear oscillator system.
Single-cycle multiterahertz transients with peak fields above 10 MV/cm
Creators: name: Junginger, F.
name: Sell, A.
name: Schubert, O.
name: Mayer, B.
name: Brida, D.
name: Marangoni, M.
name: Cerullo, G.
name: Leitenstorfer, A.
name: Huber, Rupert
Publisher: name: Universität Regensburg
Year: 2010
Subjects: subject: 530 Physik

description: Phase-locked single-cycle transients with frequency components between 1 and 60THz and peak fields of up to 12MV/cm are generated as the idler wave of a parametric amplifier. To achieve broadband conversion in GaSe nonlinear crystals, we match the group velocities of signal and idler components. The influence of group-velocity dispersion is minimized by long-wavelength pumping at 1.18μm. Free-space electro-optic sampling monitors the multiterahertz waveforms with direct field resolution.
Make Research Data Public? -- Not Always so Simple: A Dialogue for Statisticians and Science Editors
Creators: name: Sedransk, Nell
name: Cox, Lawrence H.
name: Nolan, Deborah
name: Soper, Keith
name: Spiegelman, Cliff
name: Young, Linda J.
name: Kelner, Katrina L.
name: Moffitt, Robert A.
name: Thakar, Ani
name: Raddick, Jordan
name: Ungvarsky, Edward J.
name: Carlson, Richard W.
name: Apweiler, Rolf
Publisher: name: arXiv
Year: 2010
Subjects: subject: Methodology (stat.ME)
subject: Digital Libraries (cs.DL)
subject: Data Analysis, Statistics and Probability (physics.data-an)
subject: FOS: Computer and information sciences
subject: FOS: Physical sciences

description: Putting data into the public domain is not the same thing as making those data accessible for intelligent analysis. A distinguished group of editors and experts who were already engaged in one way or another with the issues inherent in making research data public came together with statisticians to initiate a dialogue about policies and practicalities of requiring published research to be accompanied by publication of the research data. This dialogue carried beyond the broad issues of the advisability, the intellectual integrity, the scientific exigencies to the relevance of these issues to statistics as a discipline and the relevance of statistics, from inference to modeling to data exploration, to science and social science policies on these issues.
description: Published in at http://dx.doi.org/10.1214/10-STS320 the Statistical Science (http://www.imstat.org/sts/) by the Institute of Mathematical Statistics (http://www.imstat.org)
12 fs pulses from a cw-pumped 200 nJ Ti:sapphire amplifier at a variable repetition rate of up to 4 MHz
Creators: name: Huber, Rupert
name: Adler, F.
name: Leitenstorfer, A.
name: Beutter, M.
name: Baum, P.
name: Riedle, E.
Publisher: name: Universität Regensburg
Year: 2003
Subjects: subject: 530 Physik

description: We demonstrate a novel compact femtosecond Ti:sapphire laser system operating at repetition rates from 10 kHz to 4 MHz. The scheme is based on the combination of a broadband cavity-dumped oscillator and a double-pass Ti:sapphire amplifier pumped by a low-noise cw solid-state laser. Amplified pulses with an extremely smooth spectrum, a duration of only 12 fs, and less than 0.25% rms fluctuation are generated in a beam with M2 < 1.2 . A maximum pulse energy of 210 nJ and an average output power of as much as 720 mW are achieved. This output energy is sufficient to generate a stable continuum in a sapphire disk.
Theory of single electron spin relaxation in Si/SiGe lateral coupled quantum dots
Creators: name: Raith, Martin
name: Stano, Peter
name: Fabian, Jaroslav
Publisher: name: Universität Regensburg
Year: 2011
Subjects: subject: Silicon, Quantum dots, Spin Relaxation, Lifetime
subject: 530 Physik
subject: 03.67.Lx, 71.70.Ej, 72.25.Rb, 73.21.La, 73.22.Dj, 85.35.Gv

description: We investigate the spin relaxation induced by acoustic phonons in the presence of spin-orbit interactions in single electron Si/SiGe lateral coupled quantum dots. The relaxation rates are computed numerically in single and double quantum dots, in in-plane and perpendicular magnetic fields. The deformation potential of acoustic phonons is taken into account for both transverse and longitudinal polarizations, and their contributions to the total relaxation rate are discussed with respect to the dilatation and shear potential constants. We find that in single dots the spin relaxation rate scales approximately with the seventh power of the magnetic field, in line with a recent experiment. In double dots the relaxation rate is much more sensitive to the dot spectrum structure, as it is often dominated by a spin hot spot. The anisotropy of the spin-orbit interactions gives rise to easy passages, special directions of the magnetic field for which the relaxation is strongly suppressed. Quantitatively, the spin relaxation rates in Si are typically two orders of magnitude smaller than in GaAs due to the absence of the piezoelectric phonon potential and generally weaker spin-orbit interactions.
Ultrabroadband detection of multi-terahertz field transients with GaSe electro-optic sensors: Approaching the near infrared
Creators: name: Kübler, C.
name: Huber, Rupert
name: Tübel, S.
name: Leitenstorfer, A.
Publisher: name: Universität Regensburg
Year: 2004
Subjects: subject: 530 Physik

description: Field-resolved detection of ultrabroadband infrared pulses is implemented with GaSe crystals. Via phase matching, we extend the detectable frequency range toward the near infrared (λ=2.5 μm) and directly record transform-limited pulses as short as 28 fs with a 3 dB bandwidth of 41 THz. The continuous tunability of the center frequency over a wide interval ranging from 31 THz to the far-infrared is demonstrated using thick sensors.
description: » This publication has been selected for the Virtual Journal of Ultrafast Science
Elegia na śmierć żony Kakinomoto no Hitomaro a problem przekładalności poezji starojapońskiej
Creators: name: Olszewski, Krzysztof
Publisher: name: figshare
Year: 2025
Subjects: classificationCode: 470519
subject: Literature in Japanese

description: Pierwsze polskie tłumaczenie (wraz z analizą) "Elegii na śmierć żony" autorstwa jednego z najwybitniejszych starożytnych poetów japońskich - Kakinomoto no Hitomaro (660-710).
The Impact of Robots' Facial Emotional Expressions on Light Physical Exercises
Creators: name: Abdulazeem, Nourhan
name: Hu, Yue
Publisher: name: arXiv
Year: 2023
Subjects: subject: Robotics (cs.RO)
subject: FOS: Computer and information sciences

description: To address the global challenge of population aging, our goal is to enhance successful aging through the introduction of robots capable of assisting in daily physical activities and promoting light exercises, which would enhance the cognitive and physical well-being of older adults. Previous studies have shown that facial expressions can increase engagement when interacting with robots. This study aims to investigate how older adults perceive and interact with a robot capable of displaying facial emotions while performing a physical exercise task together. We employed a collaborative robotic arm with a flat panel screen to encourage physical exercise across three different facial emotion conditions. We ran the experiment with older adults aged between 66 and 88. Our findings suggest that individuals perceive robots exhibiting facial expressions as less competent than those without such expressions. Additionally, the presence of facial expressions does not appear to significantly impact participants' levels of engagement, unlike other state-of-the-art studies. This observation is likely linked to our study's emphasis on collaborative physical human-robot interaction (pHRI) applications, as opposed to socially oriented pHRI applications. Additionally, we foresee a requirement for more suitable non-verbal social behavior to effectively enhance participants' engagement levels.
Higher finiteness properties of reductive arithmetic groups in positive characteristic: the rank theorem
Creators: name: Bux, Kai-Uwe
name: Köhl, Ralf
name: Witzel, Stefan
Publisher: name: arXiv
Year: 2011
Subjects: subject: Group Theory (math.GR)
subject: Geometric Topology (math.GT)
subject: FOS: Mathematics

description: We show that the finiteness length of an $S$-arithmetic subgroup $Γ$ in a noncommutative isotropic absolutely almost simple group $G$ over a global function field is one less than the sum of the local ranks of $G$ taken over the places in $S$. This determines the finiteness properties for arithmetic subgroups in isotropic reductive groups, confirming the conjectured finiteness properties for this class of groups. Our main tool is Behr-Harder reduction theory which we recast in terms of the metric structure of euclidean buildings.
Terahertz coherent control of optically dark paraexcitons in Cu2O
Creators: name: Leinß, S.
name: Kampfrath, T.
name: v. Volkmann, K.
name: Wolf, M.
name: Steiner, J. T.
name: Kira, M.
name: Koch, S. W.
name: Leitenstorfer, A.
name: Huber, Rupert
Publisher: name: Universität Regensburg
Year: 2008
Subjects: subject: 530 Physik
subject: 71.35.Lk
subject: 78.47.−p
subject: 42.65.−k

description: Intense multiterahertz fields of order megavolts per centimeter are used to coherently promote optically dark and dense paraexcitons in Cu2O from the 1s into the 2p state. The nonlinear field response of the intraexcitonic degrees of freedom is directly monitored in the time domain via ultrabroadband electro-optic sampling. The experimental results are analyzed with a microscopic many-body theory, identifying up to two internal Rabi cycles. The effects of population inversion and ponderomotive contributions are disentangled.
description: » This publication has been selected for the Virtual Journal of Ultrafast Science
Attosecond relative timing jitter and 13 fs tunable pulses from a two-branch Er:fiber laser
Creators: name: Adler, F.
name: Sell, A.
name: Sotier, F.
name: Huber, Rupert
name: Leitenstorfer, A.
Publisher: name: Universität Regensburg
Year: 2007
Subjects: subject: 530 Physik

description: We present what is believed to be the first direct measurement of the relative timing jitter between the two parallel pulse trains of a two-branch femtosecond erbium-doped fiber laser, operated without active stabilization. The system provides independently tunable pulses in the near infrared with durations down to 13 fs. Using an interferometric optical cross-correlator, the phase-noise spectral density is measured with high sensitivity in a range from 1 Hz up to the Nyquist frequency of 24.5 MHz. We find an integrated jitter of 11 attoseconds directly after the amplifier stages and 43 as after propagation through free-space optics and nonlinear fibers for frequency conversion.
description: » This publication has been selected for the Virtual Journal of Ultrafast Science
Dynamical Matter-Parity Breaking and Gravitino Dark Matter
Creators: name: Schmidt, Jonas
name: Weniger, Christoph
name: Yanagida, Tsutomu T.
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Scenarios where gravitinos with GeV masses make up dark matter are known to be in tension with high reheating temperatures, as required by e.g. thermal leptogenesis. This tension comes from the longevity of the NLSPs, which can destroy the successful predictions of the standard primordial nucleosynthesis. However, a small violation of matter parity can open new decay channels for the NLSP, avoiding the BBN problems, while being compatible with experimental cosmic-ray constraints. In this paper, we propose a model where matter parity, which we assume to be embedded in the U(1)_{B-L} gauge symmetry, is broken dynamically in a hidden sector at low scales. This can naturally explain the smallness of the matter parity breaking in the visible sector. We discuss the dynamics of the corresponding pseudo Nambu--Goldstone modes of B-L breaking in the hidden sector, and we comment on typical cosmic-ray and collider signatures in our model.
description: 20 pages, 1 figure, 1 table
Probing cosmic isotropy in the Local Universe
Creators: name: Franco, Camila
name: Avila, Felipe
name: Bernui, Armando
Publisher: name: arXiv
Year: 2023
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: This is a model-independent analysis that investigates the statistical isotropy in the Local Universe using the ALFALFA survey data ($0 < z < 0.06$). We investigate the angular distribution of HI extra-galactic sources from the ALFALFA catalogue and study whether they are compatible with the statistical isotropy hypothesis using the two-point angular correlation function (2PACF). Aware that the Local Universe is plenty of clustered structures and large voids, we compute the 2PACF with the Landy-Szalay estimator performing directional analyses to inspect 10 sky regions. We investigate these 2PACF using power-law best-fit analyses, and determine the statistical significance of the best-fit parameters for the 10 ALFALFA regions by comparison with the ones obtained through the same procedure applied to a set of mock catalogues produced under the homogeneity and isotropy hypotheses. Our conclusion is that the Local Universe, as mapped by the HI sources of the ALFALFA survey, is in agreement with the hypothesis of statistical isotropy within $2\,σ$ confidence level, for small and large angle analyses, with the only exception of one region -- located near the Dipole Repeller -- which appears slightly outlier ($2.4\,σ$). Interestingly, regarding the large angular distribution of the HI sources, we found 3 regions where the presence of cosmic voids reported in the literature left their signature in our 2PACF, suggesting projected large underdensities there, with number-density contrast $δ\simeq -0.7$. According to the current literature these regions correspond, partially, to the sky position of the void structures known as Local Cosmic Void and Dipole Repeller.
description: 14 pages, 13 figures, 2 appendices
Temporal Characterization of Femtosecond Laser-Plasma-Accelerated Electron Bunches Using Terahertz Radiation
Creators: name: Tilborg, J. van
name: Schroeder, C. B.
name: Filip, C. V.
name: Tóth, Cs.
name: Geddes, C. G. R.
name: Fubiani, G.
name: Huber, Rupert
name: Kaindl, R. A.
name: Esarey, E.
name: Leemans, W. P.
Publisher: name: Universität Regensburg
Year: 2006
Subjects: subject: 530 Physik
subject: 29.25.Bx
subject: 41.60.−m
subject: 52.38.Kd

description: The temporal profile of relativistic laser-plasma-accelerated electron bunches has been characterized. Coherent transition radiation at THz frequencies, emitted at the plasma-vacuum boundary, was measured through electro-optic sampling. Frequencies up to the crystal detection limit of 4 THz were observed. Comparison between data and theory indicates that THz radiation from bunches with structure shorter than ≃50 fs (root-mean-square) is emitted. The measurement demonstrates both shot-to-shot stability of the laser-plasma accelerator and femtosecond synchronization between bunch and probe beam.
description: » This publication has been selected for the Virtual Journal of Ultrafast Science
Coherent terahertz control of antiferromagnetic spin waves
Creators: name: Kampfrath, Tobias
name: Sell, Alexander
name: Klatt, Gregor
name: Pashkin, Alexej
name: Mährlein, Sebastian
name: Dekorsy, Thomas
name: Wolf, Martin
name: Fiebig, Manfred
name: Leitenstorfer, Alfred
name: Huber, Rupert
Publisher: name: Universität Regensburg
Year: 2011
Subjects: subject: Spectroscopy; Ultrafast photonics; Terahertz optics
subject: 530 Physik

description: Ultrafast charge and spin excitations in the elusive terahertz regime1, 2 of the electromagnetic spectrum play a pivotal role in condensed matter3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13. The electric field of free-space terahertz pulses has provided a direct gateway to manipulating the motion of charges on the femtosecond timescale6, 7, 8, 9. Here, we complement this process by showing that the magnetic component of intense terahertz transients enables ultrafast control of the spin degree of freedom. Single-cycle terahertz pulses switch on and off coherent spin waves in antiferromagnetic NiO at frequencies as high as 1 THz. An optical probe pulse with a duration of 8 fs follows the terahertz-induced magnetic dynamics directly in the time domain and verifies that the terahertz field addresses spins selectively by means of the Zeeman interaction. This concept provides a universal ultrafast means to control previously inaccessible magnetic excitations in the electronic ground state.
Semiclassical quantization of the diamagnetic hydrogen atom with near action-degenerate periodic-orbit bunches
Creators: name: Gehrke, Jan
name: Main, Jörg
name: Wunner, Günter
Publisher: name: arXiv
Year: 2010
Subjects: subject: Chaotic Dynamics (nlin.CD)
subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: The existence of periodic orbit bunches is proven for the diamagnetic Kepler problem. Members of each bunch are reconnected differently at self-encounters in phase space but have nearly equal classical action and stability parameters. Orbits can be grouped already on the level of the symbolic dynamics by application of appropriate reconnection rules to the symbolic code in the ternary alphabet. The periodic orbit bunches can significantly improve the efficiency of semiclassical quantization methods for classically chaotic systems, which suffer from the exponential proliferation of orbits. For the diamagnetic hydrogen atom the use of one or few representatives of a periodic orbit bunch in Gutzwiller's trace formula allows for the computation of semiclassical spectra with a classical data set reduced by up to a factor of 20.
description: 10 pages, 9 figures
First-principles prediction of energy band gaps in 18-valence electron semiconducting half-Heusler compounds: Exploring the role of exchange and correlation
Creators: name: Gurbuz, Emel
name: Tas, Murat
name: Sasioglu, Ersoy
name: Mertig, Ingrid
name: Sanyal, Biplab
name: Galanakis, Iosif
Publisher: name: arXiv
Year: 2023
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: The choice of exchange functional is a critical factor in determining the energy bandgap of semiconductors. Ab initio calculations using different exchange functionals, including the conventional generalized-gradient approximation (GGA) functionals, meta-GGA functionals, and hybrid functionals, show significant differences in the calculated energy bandgap for semiconducting half-Heusler compounds. These compounds, which have 18 valence electrons per unit cell, are of great interest due to their thermoelectric properties, making them suitable for energy conversion applications. In addition, accounting for electronic correlations using the GW method also affects the calculated energy bandgaps compared to standard GGA calculations. The variations in calculated energy bandgaps are specific to each material when using different functionals. Hence, a detailed investigation of the electronic properties of each compound is necessary to determine the most appropriate functional for an accurate description of the electronic properties. Our results indicate that no general rules can be established and a comparison with experimental results is required to determine the most appropriate functional.