Miracle-dz/UniFAR-FTUs huggingface dataset:
Volume Change Estimation of Underwater Structures Using 2-D Sonar Data

Sonar sensors are an important source of data for understanding underwater environments because the sound is invariant to water turbidity, as well as illumination condition changes. This work reconstructs the surface of underwater structures and quantifies the spatial variations between multiple readings using data acquired by a 2-D mechanical scanning imaging sonar (MSIS), attached to a remotely operated vehicle (ROV). The proposed methodology is general for any underwater structure, but its main application is the melting process estimation in submerged frontal portions of glaciers. This comes up as motivation since ablation processes occurring on glacier fronts remain as one of the main inaccurate components of the glacier mass balance. The quantification of this phenomenon is crucial for estimating the consequences of glacier melting to sea level rise. Two methods are proposed to estimate volume change using sonar data. A reference plane-based system (RPBS) uses a plane behind the comparison surfaces as a reference. Moreover, the sensor line-based system (SLBS) uses the movement line of the sensor during the data acquisition process. We evaluated the proposed methods using simulated and real data acquired with an ROV with MSIS. Results show the feasibility of both methods to estimate the volume change of underwater structures.
Short-range intervortex interaction and interacting dynamics of half-quantized vortices in two-component Bose-Einstein condensates

We study the interaction and dynamics of two half-quantized vortices in two-component Bose- Einstein condensates. Using the Pade approximation for the vortex core profile, we calculate the intervortex potential, whose asymptotic form for a large distance has been derived by Eto et al. [Phys. Rev. A, 83, 063603 (2011)]. Through numerical simulations of the two-dimensional Gross-Pitaevskii equations, we reveal different kinds of dynamical trajectories of the vortices depending on the combinations of signs of circulations and the intercomponent density coupling. Under the adiabatic limit, we derive the equations of motion for the vortex coordinates, in which the motion is caused by the balance between Magnus force and the intervortex forces. The initial velocity of the vortex motion can be explained quantitatively by this point vortex approximation, but under- standing the long-time behavior of the dynamics needs more consideration beyond our model.
Modified Mean-Power-Distribution-Based Nonlinear Coefficient Optimization for Digital Back-Propagation in High-Baud-Rate Optical Systems

The digital back-propagation (DBP) is an effective algorithm to compensate for the nonlinear impairments in high-baud-rate and long-haul optical systems. The nonlinear coefficient of the DBP algorithm is optimized based on the mean power at the step position. However, when the number of steps per span of the DBP algorithm is fixed below the optimum step number to constrain computational complexity, the optimum nonlinear coefficient is sensitive to the number of steps per span. In this paper, we used the average value of the mean power over the step size to optimize the nonlinear coefficient of the DBP algorithm. The modified mean-power-distribution-based nonlinear coefficient optimization scheme was applied to constant step-size DBP (MMPD-CS-DBP) and logarithmic step-size DBP (MMPD-LS-DBP) algorithms in 30 × 80 km SSMF single-channel Nyquist 64 GBaud and 5 × 64 GBaud Nyquist WDM polarization multiplexing 16QAM systems, respectively. Simulation results showed that the optimum nonlinear coefficient of the MMPD-CS-DBP and MMPD-LS-DBP algorithms was the nonlinear coefficient of the optical fiber and was robust to the number of steps per span.
Revealing the Active Galactic Nucleus in the Superantennae through L-Band Spectroscopy

We present an L-band spectrum of the ultraluminous infrared galaxy IRAS 19254-7245 (the Superantennae), obtained with the Infrared Spectrometer and Array Camera on the Very Large Telescope. The high signal-to-noise ratio allows us to study the main spectral features with unprecedented detail for an extragalactic source. We argue that the main energy source in the IR is an obscured active galactic nucleus. This is indicated by the low equivalent width of the 3.3 μm polycyclic aromatic hydrocarbon feature, the broad absorption feature at 3.4 μm, and the steep continuum at λ > 3.7 μm (fλ ∝ λ2.7). The substructure of the 3.4 μm absorption feature indicates that the absorption is due to hydrocarbon chains of six to seven carbon atoms.
PASIPHAE: A high-Galactic-latitude, high-accuracy optopolarimetric survey

PASIPHAE (the Polar-Areas Stellar Imaging in Polarization High-Accuracy Experiment) is an optopolarimetric survey aiming to measure the linear polarization from millions of stars, and use these to create a three-dimensional tomographic map of the magnetic field threading dust clouds within the Milky Way. This map will provide invaluable information for future CMB B-mode experiments searching for inflationary gravitational waves, providing unique information regarding line-of-sight integration effects. Optical polarization observations of a large number of stars at known distances, tracing the same dust that emits polarized microwaves, can map the magnetic field between them. The Gaia mission is measuring distances to a billion stars, providing an opportunity to produce a tomographic map of Galactic magnetic field directions, using optical polarization of starlight. Such a map will not only boost CMB polarization foreground removal, but it will also have a profound impact in a wide range of astrophysical research, including interstellar medium physics, high-energy astrophysics, and evolution of the Galaxy. Taking advantage of the novel technology implemented in our high-accuracy Wide-Area Linear Optical Polarimeters (WALOPs) currently under construction at IUCAA, India, we will engage in a large-scale optopolarimetric program that can meet this challenge: a survey of both northern and southern Galactic polar regions targeted by CMB experiments, covering over 10,000 square degrees, which will measure linear optical polarization of over 360 stars per square degree (over 3.5 million stars, a 1000-fold increase over the state of the art). The survey will be conducted concurrently from the South African Astronomical Observatory in Sutherland, South Africa in the southern hemisphere, and the Skinakas Observatory in Crete, Greece, in the north.
The hyperluminous Compton-thick z ∼ 2 quasar nucleus of the hot DOG W1835+4355 observed by NuSTAR

We present a 155 ks NuSTAR observation of the z ∼ 2 hot dust-obscured galaxy (hot DOG) W1835+4355. We extracted spectra from the two NuSTAR detectors and analyzed them jointly with the archival XMM-Newton PN and MOS spectra. We performed a spectroscopic analysis based on both phenomenological and physically motivated models employing toroidal and spherical geometry for the obscurer. In all the modelings, the source exhibits a Compton-thick column density NH ≳ 1024 cm−2, a 2–10 keV luminosity L2−10 ≈ 2 × 1045 erg s−1, and a prominent soft excess (∼5–10% of the primary radiative output), which translates into a luminosity ∼1044 erg s−1. We modeled the spectral energy distribution from 1.6 to 850 μm using a clumpy two-phase dusty torus model plus a modified blackbody to account for emission powered by star formation in the far-infrared. We employed several geometrical configurations consistent with those applied in the X-ray analysis. In all cases we obtained a bolometric luminosity Lbol ≈ 3–5 × 1047 erg s−1, which confirms the hyperluminous nature of this active galactic nucleus. Finally, we estimate a prodigious star formation rate of ∼3000 M⊙ yr−1, which is consistent with the rates inferred for z ≈ 2–4 hyperluminous type I quasars. The heavily obscured nature, together with Lbol, the ratio of X-ray to mid-infrared luminosity, the rest-frame optical morphology, and the host star formation rate are indicative of its evolutionary stage. We can interpret this as a late-stage merger event in the transitional, dust-enshrouded, evolutionary phase eventually leading to an optically bright AGN.
Outage and Error-Rate Analysis of NOMA-Inspired Multicarrier Underlay Cognitive Radio System

In this paper, the performance of a multicarrier underlay cognitive radio system is analyzed considering that the successive interference cancellation (SIC) method is used for detection. In the proposed system model, a multicarrier-based secondary user (SU) uses all the subcarriers of the primary user (PU) in underlay mode, guaranteeing the quality of service (QoS) to the primary system. The power allocation strategy is modified accordingly. With a fixed PU transmit power, power is allocated to the SU subcarriers to maximize its throughput while ensuring minimum throughput to PU. The system is analyzed for its performance considering an L-tap multipath Rayleigh fading channel. Analytical expression for outage probability at SU is derived in closed-form. Also, analytical expressions and closed-form approximations for average symbol error rates (SER) per subcarrier of PU and SU are obtained. The derived expressions are validated with the Monte-Carlo (MC) simulations. Further, the proposed scheme was implemented in an orthogonal frequency division multiplexing (OFDM)-based system with different detection schemes used at the receiver. SERs were compared through extensive simulations and it was noticed that SIC with channel estimation based on minimum-mean-squared-error (MMSE) often performed better than that based on least squares (LS) estimation. Observations reveal that the nominal error rates were achieved on the optimal choice of the parameters. The proposed system ensures sufficient throughput to SU, meanwhile eliminating the need for opportunistic sensing.
High efficiency Raman memory by suppressing radiation trapping

Raman interactions in alkali vapours are used in applications such as atomic clocks, optical signal processing, generation of squeezed light and Raman quantum memories for temporal multiplexing. To achieve a strong interaction the alkali ensemble needs both a large optical depth and a high level of spin-polarisation. We implement a technique known as quenching using a molecular buffer gas which allows near-perfect spin-polarisation of over 99.5 % in caesium vapour at high optical depths of up to ∼ 2 × 10 5 ; a factor of 4 higher than can be achieved without quenching. We use this system to explore efficient light storage with high gain in a GHz bandwidth Raman memory.
PRIMUS: Clustering of Star-forming and Quiescent Central Galaxies at 0.2 < z < 0.9

Previous work has demonstrated that at a given stellar mass, quiescent galaxies are more strongly clustered than star-forming galaxies. The contribution to this signal from central, as opposed to satellite, galaxies is not known, which has strong implications for galaxy evolution models. To investigate the contribution from central galaxies, here we present measurements of the clustering of isolated primary (IP) galaxies, used as a proxy for central galaxies, at 0.2 < z < 0.9 with data from the PRIsm MUlti-Object Survey (PRIMUS) galaxy redshift survey. Using a sample of spectroscopic redshifts for ∼60,000 galaxies with covering 5 deg2 on the sky, we define IP galaxies using isolation cuts in spatial proximity and stellar mass of nearby galaxies. We find that at a fixed stellar mass, quiescent IP galaxies are more strongly clustered than star-forming IP galaxies at z ∼ 0.35 (10σ). Using mock galaxy catalogs based on the recent halo occupation models of Behroozi et al. and designed to replicate the parameters of the PRIMUS survey data set, we find that these clustering differences are due in part to quiescent central galaxies being more strongly clustered than star-forming central galaxies. This is consistent with either distinct stellar-to-halo mass relations for quiescent and star-forming central galaxies, and/or central galaxy assembly bias. We additionally use mock catalogs to assess the dependence of both incompleteness and satellite galaxy contamination in the IP galaxy samples on redshift, galaxy type, and stellar mass, and demonstrate how isolation criteria yield biased subsamples of central galaxies via environmental incompleteness, or the preferential exclusion of central galaxies in overdense environments.
A new globular cluster black hole in NGC 4472

We discuss CXOU 1229410+075744, a new black hole candidate in a globular cluster in the elliptical galaxy NGC 4472. By comparing two Chandra observations of the galaxy, we find a source that varies by at least a factor of 4, and has a peak luminosity of at least 2 x 10 39 erg s -1 . As such, the source varies by significantly more than the Eddington luminosity for a single neutron star, and is a strong candidate for being a globular cluster black hole. The source's X-ray spectrum also evolves in a manner consistent with what would be expected from a single accreting stellar mass black hole. We consider the properties of the host cluster of this source and the six other strong black hole X-ray binary candidates, and find that there is suggestive evidence that black hole X-ray binary formation is favoured in bright and metal-rich clusters, just as is the case for bright X-ray sources in general.
Thermal production of relativistic Majorana neutrinos: strong enhancement by multiple soft scattering

The production rate of heavy Majorana neutrinos is relevant for models of thermal leptogenesis in the early Universe. In the high temperature limit the production can proceed via the 1↔2 (inverse) decays which are allowed by the thermal masses. We consider new production mechanisms which are obtained by including additional soft gauge interactions with the plasma. We show that an arbitrary number of such interactions gives leading order contributions, and we sum all of them. The rate turns out to be smooth in the region where the 1↔2 processes are kinematically forbidden. At higher temperature it is enhanced by a factor 3 compared to the 1↔2 rate.
Causes and Psycholinguistic Correlates of Interpersonal Equivocation

A study examined the longstanding theory of the Bavelas group which suggests that the only consistent cause of interpersonal equivocation is avoidance-avoidance conflict (AAC) . The study also aimed to uncover a psycholinguistic profile of equivocation, especially in the form of paralinguistic cues such as disfluencies. Subjects, 18 college undergraduates, responded orally to questions from hypothetical interlocutors within scenarios designed to manipulate both the presence/absence of AAC and level of situational formality. Their responses were audiotaped, transcribed, rated for degree of equivocation, and coded for disfluencies. Results of ANOVA showed that AAC did result in equivocation, but also that formality level interacted with AAC in influencing equivocation. Subjects used filled pauses, surprisingly, in the condition within which they equivocated the least, although they produced other disfluencies (combined) within conditions where they equivocated the most. Findings demonstrate that, with regard to the antecedents of equivocation, the Bavelas group was right in claiming that AAC routinely leads to increased equivocation. Future research should aim for a clearer conceptual definition of "formality," and the search for antecedents should extend to individual differences as well. A more reliable method of rating degree of equivocation (as defined by Bavelas) must be used, employing more trained judges. With regard to the psycholinguistic profile of equivocation, the notion that both filled pauses and false starts might provide a substantive index of AAC-based equivocation are not supported. (Contains 2 tables of data and 12 references; an appendix contains "experimental stimuli.") (NKA) ******************************************************************************** * Reproductions supplied by EDRS are the best that can be made * * from the original document. * ********************************************************************************
Variations of the Fine Structure Constant in Space and Time

This thesis describes a detailed investigation of the effects of matter inhomogeneities on the cosmological evolution of the fine structure constant using the Bekenstein-Sandvik-Barrow-Magueijo (BSBM) theory. We briefly review the observational and theoretical motivations to this work, together with the standard cosmological model. We start by analysing the phase space of the system of equations that describes a time-varying fine structure constant, in a homogeneous and isotropic background universe. We classify all the possible behaviours of the fine structure constant in ever-expanding universes and find exact solutions for it. Using a gauge-invariant formalism, we derive and solve the linearly perturbed Einstein cosmological equations for the BSBM theory. We calculate the time evolution of inhomogeneous perturbations of the fine structure constant on small and large scales with respect to the Hubble radius. We also investigate, in the non-linear regime of the large scale structure formation, the space-time evolution of the fine structure constant, inside evolving spherical overdensities. The dependence on the dark-energy equation of state is also analysed. Finally, we analyse the effects of the coupling of the field (that drives the variations in the fine structure constant) to the matter fields, on the space and time evolution of the fine structure constant.
Signatures of Distinct Nucleosynthesis Events among Metal-Poor Stars

Recently, the Peterson (2011) analysis of Mo II lines near 20 00Å uncovered molybdenum overabundances of nearly a factor of ten in two mildly metal-poor turnoff stars with moderate to no ror s-process enhancement. Because previous analyses of two doz en metal-poor giants of similarly low r-process enhancement had shown only low molybdenum excesse s, never exceeding a factor of three, these extreme overabundances raised the po ssibility that distinct nucleosynthesis events were responsible for molybdenum overproduction in t hese two cases. This is unexpected given the mild rather than extreme overall metal deficiency o f these two stars. Here we present a progress report of determinations of molybdenum abundanc es based on optical Mo I lines seen in archival spectra of two dozen additional turnoff stars of imilar metallicity. We conclude that distinct events do not seem to be required, for most turnoff h alo field stars with−1.8≤ [Fe/H] ≤ −1.4 have moderate to high molybdenum abundance excesses. Inde ed, nineteen of the 28 stars presently analyzed have +0.4≤ [Mo/Fe]≤ +0.8. We mention several ramifications of this result for early nucleosynthesis of the lightest trans-ironic ele ments in metal-poor stars.
Recent Development of Carbon-Nanotube-Based Solar Heat Absorption Devices and Their Application

Population growth and the current global weather patterns have heightened the need to optimize solar energy harvesting. Solar-powered water filtration, electricity generation, and water heating have gradually multiplied as viable sources of fresh water and power generation, especially for isolated places without access to water and energy. The unique thermal and optical characteristics of carbon nanotubes (CNTs) enable their use as efficient solar absorbers with enhanced overall photothermal conversion efficiency under varying solar light intensities. Due to their exceptional optical absorption efficiency, low cost, environmental friendliness, and natural carbon availability, CNTs have attracted intense scientific interest in the production of solar thermal systems. In this review study, we evaluated CNT-based water purification, thermoelectric generation, and water heating systems under varying solar levels of illumination, ranging from domestic applications to industrial usage. The use of CNT composites or multilayered structures is also reviewed in relation to solar heat absorber applications. An aerogel containing CNTs was able to ameliorate water filtering performance at low solar intensities. CNTs with a Fresnel lens improved thermoelectric output power at high solar intensity. Solar water heating devices utilizing a nanofluid composed of CNTs proved to be the most effective. In this review, we also aimed to identify the most relevant challenges and promising opportunities in relation to CNT-based solar thermal devices.
Detection of Gamma Rays around 1 TeV from RX J0852.0–4622 by CANGAROO-II

We have detected gamma-ray emission at the 6 σ level at energies greater than 500 GeV from the supernova remnant RX J0852.0-4622 (G266.2-1.2) using the CANGAROO-II imaging atmospheric Cerenkov telescope. The flux was 0.12 times that of Crab at 1 TeV. The signal centroid is consistent with the peak of the X-ray emission in the northwest rim of the remnant.
Deconstructing double-barred galaxies in 2D and 3D – II. Two distinct groups of inner bars

The intrinsic photometric properties of inner and outer stellar bars within 17 double-barred galaxies are thoroughly studied through a photometric analysis consisting of (i) two-dimensional (2D) multicomponent photometric decompositions, and (ii) three-dimensional (3D) statistical deprojections for measuring the thickening of bars, thus retrieving their 3D shape. The results are compared with previous measurements obtained with the widely used analysis of integrated light. Large-scale bars in single- and double-barred systems show similar sizes, and inner bars may be longer than outer bars in different galaxies. We find two distinct groups of inner bars attending to their in-plane length and ellipticity, resulting in a bimodal behaviour for the inner/outer bar length ratio. Such bimodality is related neither to the properties of the host galaxy nor the dominant bulge, and it does not show a counterpart in the dimension off the disc plane. The group of long inner bars lays at the lower end of the outer bar length versus ellipticity correlation, whereas the short inner bars are out of that relation. We suggest that this behaviour could be due to either a different nature of the inner discs from which the inner bars are dynamically formed or a different assembly stage for the inner bars. This last possibility would imply that the dynamical assembly of inner bars is a slow process taking several Gyr to happen. We have also explored whether all large-scale bars are prone to develop an inner bar at some stage of their lives, possibility we cannot fully confirm or discard.
Using an Online Tool to Apply a Person-Centred Approach in Audiological Rehabilitation: A Pilot Study

This study aimed to explore the experiences of adult clients with hearing loss and their audiologists in using an online tool, the Living Well Tool (LWT), during initial audiology appointments. The LWT is designed to help clients identify when and where it is most important for them to communicate effectively and live well with hearing loss. A total of 24 adult clients with hearing loss and two audiologists participated in this study. Clients were invited to complete the LWT prior to their next audiology appointment, however, most clients chose to use the LWT in-session with their audiologist. Following the appointment, clients and audiologists participated in individual qualitative semi-structured interviews to explore their experiences of using the LWT, and the extent to which the LWT facilitated person-centred care. Qualitative analysis five key themes which reflected participants’ experiences and perceptions of using the LWT: (1) the LWT enhances audiological care; (2) the LWT supports person-centred audiological care; (3) the use of the LWT should be individualised; (4) users value comprehensiveness; and (5) users value accessibility. This study demonstrated that the LWT supported the provision of person-centred audiological care, providing a flexible, comprehensive and accessible means for audiologists to gain an understanding of their clients’ needs and preferences. However, it was also noted that the use of a tool must be individualised and accessible for all.