Miracle-dz/UniFAR-FTUs huggingface dataset:
A Hubble Space Telescope Snapshot Survey of Dynamically Close Galaxy Pairs in the CNOC2 Redshift Survey

We compare the structural properties of two classes of galaxies at intermediate redshift: those in dynamically close galaxy pairs, and those that are isolated. Both samples are selected from the Canadian Network for Observational Cosmology field galaxy redshift survey (CNOC2) and have redshifts in the range 0.1 < z < 0.6. Hubble Space Telescope WFPC2 images were acquired as part of a snapshot survey and were used to measure bulge fraction and asymmetry for these galaxies. We find that paired and isolated galaxies have identical distributions of bulge fractions. Conversely, we find that paired galaxies are much more likely to be asymmetric (RT + RA ≥ 0.13) than isolated galaxies. Assuming that half of these pairs are unlikely to be close enough to merge, we estimate that 40% ± 11% of merging galaxies are asymmetric, compared with 9% ± 3% of isolated galaxies. The difference is even more striking for strongly asymmetric (RT + RA ≥ 0.16) galaxies: 25% ± 8% for merging galaxies versus 1% ± 1% for isolated galaxies. We find that strongly asymmetric paired galaxies are very blue, with rest-frame B-R colors close to 0.80, compared with a mean (B-R)0 of 1.24 for all paired galaxies. In addition, asymmetric galaxies in pairs have strong [O II] λ3727 emission lines. We conclude that close to half of the galaxy pairs in our sample are in the process of merging and that most of these mergers are accompanied by triggered star formation.
Bayesian Multiple Change-Point Estimation and Segmentation

This study presents a Bayesian multiple change-point detection approach to segment and classify the observations that no longer come from an initial population after a certain time. Inferences are based on the multiple change-points in a sequence of random variables where the probability distribution changes. Bayesian multiple change-point estimation is classifies each observation into a segment. We use a truncated Poisson distribution for the number of change-points and conjugate prior for the exponential family distributions. The Bayesian method can lead the unsupervised classification of discrete, continuous variables and multivariate vectors based on latent class models; therefore, the solution for change-points corresponds to the stochastic partitions of observed data. We demonstrate segmentation with real data.
Quantum Dilatonic Gravity in d=2,4 and 5 Dimensions

We review (mainly) quantum effects in the theories where the gravity sector is described by metric and dilaton. The one-loop effective action for dilatonic gravity in two and four dimensions is evaluated. Renormalization group equations are constructed. The conformal anomaly and induced effective action for 2d and 4d dilaton coupled theories are found. It is applied to the study of quantum aspects of black hole thermodynamics, like calculation of Hawking radiation and quantum corrections to black hole parameters and investigation of quantum instability for such objects with multiple horizons. The use of the above effective action in the construction of nonsingular cosmological models in Einstein or Brans–Dicke (super)gravity and investigation of induced wormholes in supersymmetric Yang–Mills theory are given. 5d dilatonic gravity (bosonic sector of compactified IIB supergravity) is discussed in connection with bulk/boundary (or AdS/CFT) correspondence. Running gauge coupling and quark–antiquark potential for boundary gauge theory at zero or nonzero temperature are calculated from d=5 dilatonic anti-de Sitter-like background solution which represents anti-de Sitter black hole for periodic time.
Health Monitoring of Cracked Rotor Systems Using External Excitation Techniques

Cracked rotors present a significant safety and loss hazard in nearly every application of modern turbomachinery. This thesis focuses on the health monitoring, modeling, and analysis of machines with transverse breathing cracks, which open and close due to the self-weight of the rotor. After considering the modeling of cracked rotors, the thesis investigates an active structural health monitoring approach, focusing on the application of an active magnetic actuator to apply a specially designed external force excitation to the rotating shaft. Extensive experimental data has been collected and analyzed utilizing advanced diagnostic techniques. The presented results demonstrate that the use of a magnetic force actuator to apply external excitation has potential in the diagnostics of cracked rotors. The observed unique crack signatures demonstrate the ability of the method for early diagnosis of transverse rotor cracks.
Effects of Cr Doping on the Electronic Structure of MnTe

The e ects of Cr doping on the electronic structure of semiconducting MnTe have been investigated by using electron and optical spectroscopies. All CrxMn1 xTe samples grown as polycrystalline lms by molecular beam epitaxy on Si(100) substrates showed a NiAs structure with little change in lattice parameters for x 0.15. X-ray photoelectron spectroscopy and spectroscopic ellipsometry results suggest the existence of spin-polarized Mn d bands in CrxMn1 xTe. The majorityand the minority-spin d bands are likely to be located 4 eV below and 3 eV above the Fermi level, respectively. The direct optical-band-gap of CrxMn1 xTe is found to gradually decrease with increasing x in the infrared region. A ferromagnetic behavior was observed for the CrxMn1 xTe lms. The possible origin for the ferromagnetism is the coupling of Cr spins mediated by spin-polarized holes in the valence bands created through the hybridization between Te p and Cr d states.
CHILES: H  imorphology and galaxy environment atz = 0.12 andz = 0.17

We present a study of 16 H I-detected galaxies found in 178 h of observations from Epoch 1 of the COSMOS H I Large Extragalactic Survey (CHILES). We focus on two redshift ranges between 0.108 ≤ z ≤ 0.127 and 0.162 ≤ z ≤ 0.183 which are among the worst affected by radio frequency interference (RFI). While this represents only 10 per cent of the total frequency coverage and 18 per cent of the total expected time on source compared to what will be the full CHILES survey, we demonstrate that our data reduction pipeline recovers high-quality data even in regions severely impacted by RFI. We report on our in-depth testing of an automated spectral line source finder to produce H I total intensity maps which we present side-by-side with significance maps to evaluate the reliability of the morphology recovered by the source finder. We recommend that this become a common place manner of presenting data from upcoming H I surveys of resolved objects. We use the COSMOS 20k group catalogue and extract the filamentary structure using the topological DisPerSE algorithm to evaluate the H I morphology in the context of both local and large-scale environments and we discuss the shortcomings of both methods. Many of the detections show disturbed H I morphologies suggesting they have undergone a recent interaction which is not evident from deep optical imaging alone. Overall, the sample showcases the broad range of ways in which galaxies interact with their environment. This is a first look at the population of galaxies and their local and large- scale environments observed in H I by CHILES at redshifts beyond the z = 0.1 Universe.
Aspects of string theory compactifications: D-brane statistics and generalised geometry

In this thesis two different aspects of string theory compactifications are investigated. The first part deals with the issue of the huge amount of possible string vacua, known as the landscape. Concretely we investigate a specific well defined subset of type II orientifold compactifications. We develop the necessary tools to construct a very large set of consistent models and investigate their gauge sector on a statistical basis. In particular we analyse the frequency distributions of gauge groups and the possible amount of chiral matter for compactifications to six and four dimensions. In the phenomenologically relevant case of four-dimensional compactifications, special attention is paid to solutions with gauge groups that include those of the standard model, as well as Pati-Salam, SU(5) and flipped SU(5) models. Additionally we investigate the frequency distribution of coupling constants and correlations between the observables in the gauge sector. These results are compared with a recent study of Gepner models. Moreover, we elaborate on questions concerning the finiteness of the number of solutions and the computational complexity of the algorithm. In the second part of this thesis we consider a new mathematical framework, called generalised geometry, to describe the six-manifolds used in string theory compactifications. In particular, the formulation of T-duality and mirror symmetry for nonlinear topological sigma models is investigated. Therefore we provide a reformulation and extension of the known topological A- and B-models to the generalised framework. The action of mirror symmetry on topological D-branes in this setup is presented and the transformation of the boundary conditions is analysed. To extend the considerations to D-branes in type II string theory, we introduce the notion of generalised calibrations. We show that the known calibration conditions of supersymmetric branes in type IIA and IIB can be obtained as special cases. Finally we investigate the action of T-duality on the generalised calibrations.
Time‐resolved spectroscopy of the variable brown dwarf Kelu‐1★

We report the results of observations designed to investigate the spectroscopic signatures of dust clouds on the L2 brown dwarf Kelu-1. Time-resolved medium-resolution spectra show no significant evidence of variability in the dust-sensitive TiO, CrH and FeH bandheads on a time-scale of 1-24 h. We do, however, report periodic variability in the pseudo-equivalent width of Ha consistent with the 1.8-h rotation period previously reported for this object. Near-contemporaneous I-band photometry shows evidence for non-periodic variability at the level of 2 per cent.
Electronic Specific Heat of La2-xSrxCuO4: Pseudogap Formation and Reduction of the Superconducting Condensation Energy

To examine the so-called small pseudogap and the superconducting (SC) condensation energy U (0), the electronic specific heat C el was measured on La 2- x Sr x CuO 4 up to ∼120 K. In samples with doping level p (= x ) less than ∼0.2, small pseudogap behavior appears in the γ (= C el / T ) vs T curve around the mean-field critical temperature for a d -wave superconductor T co (=2Δ 0 /(4–5) k B ), where Δ 0 is the maximum gap at T ≪ T c . The condensation energy U (0) is largely reduced in the pseudogap regime (\( p\lesssim 0.2\)). The reduction of U (0) can be well reproduced by introducing an effective SC energy scale Δ 0 eff =β p Δ 0 (β=4.5) instead of Δ 0 . The effective SC energy scale is discussed in relation to the coherent pairing gap formed over the nodal Fermi arc.
An interpretation for the bipolar electric field structures parallel to the magnetic field observed in the auroral ionosphere

A physical model for the existence of bipolar structures in the electric field that are parallel to the magnetic field and observed in the auroral ionosphere, is established by deriving the "Sagdeev potential" from the two-fluid equa- tions in a cylindrical coordinate system. The model shows that the bipolar electric field structure can develop not only from an ion acoustic wave, but also from an ion cyclotron wave, when the Mach number and the initial electric field satisfy certain conditions. Moreover, in the auroral region, it shows that the polarity of this electric field structure can be oriented either negative to positive or the reverse polarity, its amplitude can be varied from 35 to 330 mV/m, and its du- ration can be 7 ms to 23 ms. These results are in agreement with observation. Therefore, our two-fluid model can inter- pret the bipolar structures observed in the auroral ionosphere.
On the discrete approximation of occupation time of diffusion processes

for the occupation time ∫ t 0 IA(Xs)ds of process X in some set A. The main concern of this paper is the rates of convergence of the estimators. First, we consider the case that A is a finite union of some intervals in R, then we show that the estimator converges at rate n−3/4. Second, we consider the so-called stochastic corridor in mathematical finance. More precisely, we let A be a stochastic interval, say [Xt0 ,∞) for some t0 ∈ (0, t), then we show that the estimator converges at rate n−1/2. Some discussions about the exactness of the rates are also presented.
The Radial Distribution of Mono-metallicity Populations in the Galactic Disk as Evidence for Two-phase Disk Formation

Recent determinations of the radial distributions of mono-metallicity populations (MMPs, i.e., stars in narrow bins in [Fe/H] within wider [α/Fe] ranges) by the SDSS-III/APOGEE DR12 survey cast doubts on the classical thin- and thick-disk dichotomy. The analysis of these observations led to the non- /Fe] enhanced populations splitting into MMPs with different surface densities according to their [Fe/H]. By contrast, /Fe] enhanced (i.e., old) populations show a homogeneous behavior. We analyze these results in the wider context of disk formation within non-isolated halos embedded in the Cosmic Web, resulting in a two-phase mass assembly. By performing hydrodynamical simulations in the context of the ΛCDM model, we have found that the two phases of halo mass assembly (an early fast phase, followed by a slow phase with low mass-assembly rates) are very relevant to determine the radial structure of MMP distributions, while radial mixing only plays a secondary role, depending on the coeval dynamical and/or destabilizing events. Indeed, while the frequent dynamical violent events occuring at high redshift remove metallicity gradients and imply efficient stellar mixing, the relatively quiescent dynamics after the transition keeps [Fe/H] gaseous gradients and prevents newly formed stars from suffering strong radial mixing. By linking the two-component disk concept with the two-phase halo mass-assembly scenario, our results set halo virialization (the event marking the transition from the fast to the slow phases) as the separating event that marks periods that are characterized by different physical conditions under which thick- and thin-disk stars were born.
Precise radial velocities of giant stars I. Stable stars

Context. Future astrometric missions such as SIM PlanetQuest need very stable reference stars. K giants have large luminosities, which place them at large distances and thus the jitter of their photocenters by companions is relatively small. Therefore K giants would be best suited as references. To confirm this observationally a radial velocity survey is performed to quantify the level of intrinsic variability in K giants. Aims. From this radial velocity survey we present 34 K giants with an observed standard deviation of the radial velocity of less than 20 m/s. These stars are considered “stable” and can be used as radial velocity standards. Methods. The radial velocity survey contains 179 K giants. All K giants have a declination between −30 ◦ and +65 ◦ and visual magnitude of 3−6 mag. The Coude Auxiliary Telescope (CAT) at UCO/Lick Observatory is used to obtain radial velocities with an accuracy of 5− 8m /s. The number of epochs for the 34 stable stars ranges from 11 to 28 with a total timespan of the observations between 1800 and a little over 2200 days. Results. The observational results of the 34 “stable” stars are shown together with a discussion about their position in the MV vs. B − V diagram and some conclusions concerning the radial velocity variability of K giants. These results are in agreement with the theoretical predictions. K giants in a certain range of the MV vs. B − V diagram are suitable reference stars.
M2- and M5-branes in E11 Current Algebra Formulation of M-theory

Equations of motion for M2- and M5-branes are written down in the $E_{11}$ current algebra formulation of M-theory. These branes correspond to currents of the second and the fifth rank antisymmetric tensors in the $E_{11}$ representation, whereas the electric and magnetic fields (coupled to M2- and M5-branes) correspond to currents of the third and the sixth rank antisymmetric tensors, respectively. We show that these equations of motion have solutions in terms of the coordinates on M2- and M5-branes. We also discuss the geometric equations, and show that there are static solutions when M2- or M5-brane exists alone and also when M5-brane wraps around M2-brane. This situation is realized because our Einstein-like equation contains an extra term which can be interpreted as gravitational energy contributing to the curvature, thus avoiding the usual intersection rule.
Assessment of Knowledge and Usage of Oral Rehydration Therapy in Management of Childhood Diarrhea among Mothers of Kambaza town, Kebbi State, Nigeria

Diarrhea is one of the major causes of infant and young children morbidity and mortality globally. It is characterized by passing of more than 3 watery stools within 24hr which is accompanied by loss of body fluids and electrolytes leading dehydration and death if not treated. Therefore, this study was aimed in assessing knowledge and use of Oral Rehydration Therapy (ORT) in the management of childhood diarrhea among mothers. A cross sectional descriptive study was conducted among 103 mothers living in Kambaza metropolis using a questionnaire for quantitative data collection. The data were analyzed using Statistical Package for Social Sciences (SPSS), version 20 and p-value <0.05 was considered statistically significant. The results showed that a significant proportion of respondents were below the age of 36 years (25-35years) with the mean age of 30±0.327 years and most of them (92.2%) were married. 81.6% of the respondents heard knowledge about ORT and majority of them (82.5%) indicated they know to prepare ORS/SSS. The use of ORT in the management of childhood diarrhea was also found to be high (82.5%) among the mothers. A significant portion of the mothers (95.1%) indicated already made ORS sachet was more effective in treating diarrhea than home-made SSS. There is no significant relationship between maternal level education and use of ORT in the management child diarrhea (p=0.476). However, a significant relationship exit between maternal knowledge on ORT preparation and its usage for management of childhood diarrhea (p=0.037). This study recorded high knowledge and use of ORT for management of childhood diarrhea among mothers of under-five children. Therefore, it recommended that maternal knowledge on use of ORT and its preparation should be encourage.
Electromigration in thin tunnel junctions with ferromagnetic/nonmagnetic electrodes: Nanoconstrictions, local heating, and direct and wind forces

Current Induced Resistance Switching (CIS) was recently observed in thin tunnel junctions with ferromagnetic (FM) electrodes, i.e., FM/I/FM. This effect was attributed to electromigration of metallic atoms in nanoconstrictions in the insulating barrier (I). Here we study how the CIS effect is influenced by a thin nonmagnetic (NM) Ta layer, deposited just below the $\mathrm{Al}{\mathrm{O}}_{x}$ insulating barrier in tunnel junctions of the type FM/NM/I/FM $(\mathrm{FM}\mathrm{Co}\mathrm{Fe})$. Enhanced resistance switching occurs with increasing maximum applied current $({I}_{\mathrm{max}})$, until a plateau of constant CIS is reached for ${I}_{\mathrm{max}}\ensuremath{\sim}65\phantom{\rule{0.3em}{0ex}}\mathrm{mA}\phantom{\rule{0.3em}{0ex}}(\mathrm{CIS}\ensuremath{\sim}60%)$ and above. However, such high electrical currents also lead to a large $(\ensuremath{\sim}9%)$ irreversible resistance decrease, indicating barrier degradation. Anomalous voltage-current characteristics with negative derivative were also observed near $\ifmmode\pm\else\textpm\fi{}{I}_{\mathrm{max}}$ and this effect is here attributed to heating in the tunnel junction. One observes that the current direction for which resistance switches in FM/NM/I/FM (clockwise) is opposite to that of FM/I/FM tunnel junctions (anti-clockwise). This effect will be discussed in terms of a competition between the electromigration contributions due to the so-called direct and wind forces. It will be shown that the direct force is likely to dominate electromigration in the Ta (NM) layers, while the wind contribution likely dominates in the CoFe (FM) layers.
Interplay between s-d exchange interaction and Rashba effect: Spin-polarized transport

The authors investigate the spin-polarized transport properties of a two-dimensional electron gas in a n-type diluted magnetic narrow gap semiconductor quantum well subjected to perpendicular magnetic and electric fields. Interesting beating patterns in the magnetoresistance are found which can be tuned significantly by varying the electric field. A resonant enhancement of spin-polarized current is found which is induced by the competition between the s-d exchange interaction and the Rashba effect [Y. A. Bychkov and E. I. Rashba, J. Phys. C 17, 6039 (1984)]. (c) 2006 American Institute of Physics.
Gas dynamics in the barred Seyfert galaxy NGC 4151 - I. H I streaming shocks and inflow along the bar

We present sensitive, high-resolution observations of neutral hydrogen (H I) in the unusually gas-rich, oval distortion of the Seyfert galaxy NGC 4151. The gas dynamics of the oval are found to be consistent with those of a kinematically weak bar, fully confirming previous suggestions for the presence of a fat bar, and, for the first time, individual gaseous features in the bar are spatially resolved. In particular, the two bright regions close to the leading edges of the bar in NGC 4151 exhibit kinematics strikingly similar to the signature of bar shocks seen in gas-dynamical simulations, and demonstrate how strong the gaseous response may be even in such a weak bar potential. The residual velocity field, showing deviations from circular motion, is largely consistent with streaming in a bar potential, and, in addition, clearly shows that inflow is concentrated in narrow regions originating in the shocks. This inflow may represent an early stage in the fuelling process of the AGN. The presence and properties of the shocks in NGC 4151 indicate that, in addition to the x1 orbits, the family of x2 orbits exists and is of significant extent in the bar of NGC 4151, with gas streaming from the shocks making the transition between the two families. We therefore suggest that the circumnuclear ellipse, identified optically by previous authors and associated with gas flowing in x2 orbits, has formed as a natural consequence of the gas flows in the bar without the requirement for a second, inner bar. Observations of H I were previously thought to be ill-suited to the study of bar shocks because of limitations in angular resolution and sensitivity. However, our observations show that, following recent instrumental enhancements, such measurements are now feasible, albeit at the limits of instrumental capability.