Miracle-dz/UniFAR-FTUs huggingface dataset:
Photon Statistics and Spectrum of Transmitted Light in Optical Bistability

A quantum description of the transmitted field is given. In the bistable situation, the stationary Glauber quasi probability distribution has two peaks thereby producing a first-order phase transition. For small incident field the linewidth of the transmitted light is proportional to the atomic density and becomes very narrow as the field approaches some critical value from below. Crossing this value the spectrum splits discontinuously into a triplet (dynamical Stark shift) where the central peak is as high as twice the side-bands.
Representation of Clouds in Large-Scale Models

Abstract A prognostic scheme for stratiform and convective clouds is developed for large-scale models. The time evolution of clouds is defined through the large-scale budget equations for cloud water content and cloud air (which is converted into a prognostic equation for fractional cloud cover). The scheme considers the formation of clouds in connection with large-scale ascent diabatic cooling, boundary-layer turbulence, and horizontal transport of cloud water from convective updrafts. Clouds dissipate through adiabatic and diabatic heating, turbulent mixing of cloud air with unsaturated environmental air, and depletion of cloud water by precipitation. The scheme differs from conventional schemes in its approach, which is fully prognostic and model consistent, and in the larger degree of complexity as the formation of anvil and circus clouds originating by cumulus updrafts and boundary-layer clouds is included. The scheme has been tested in the European Centre for Medium-Range Weather Forecasts (ECMWF) g.
GHRS observations of cool, low-gravity stars. 1: The far-ultraviolet spectrum of alpha Orionis (M2 Iab)

We present far-UV (1200-1930 A) observations of the prototypical red supergiant star alpha Ori, obtained with the Goddard High Resolution Spectrograph (GHRS) on the Hubble Space Telescope (HST). The observations, obtained in both low- (G140L) and medium- (G160/200M) resolution modes, unamibiguously confirm that the UV 'continuum' tentatively seen with (IUE) is in fact a true continuum and is not due to a blend of numerous faint emission features or scattering inside the IUE spectrograph. This continuum appears to originate in the chromospheric of the star at temperatures ranging from 3000-5000 K, and we argue that it is not related to previously reported putative companions or to bright spots on the stellar disk. Its stellar origin is further confirmed by overlying atomic and molecular absorptions from the chromosphere and circumstellar shell. The dominant structure in this spectral region is due to nine strong, broad absorption bands of the fourth-positive A-X system of CO, superposed on this continuum in the 1300-1600 A region. Modeling of this CO absorption indicates that it originates in the circumstellar shell in material characterized by T = 500 K, N(CO) = 1.0 x 10(exp 18) per sq cm, and V(sub turb) = 5.0 km per sec. The numerous chromospheric emission features are attributed mostly to fluorescent lines of Fe II and Cr II (both pumped by Lyman Alpha) and S I lines, plus a few lines of O I, C I, and Si II. The O I and C I UV 2 multiplets are very deficient in flux, compared to both the flux observed in lines originating from common upper levels but with markedly weaker intrinsic strength (i.e., O I UV 146 and C I UV 32) and to the UV 2 line fluxes seen in other cool, less luminous stars. This deficiency appears to be caused by strong self-absorption of these resonance lines in the circumstellar shell and/or upper chromosphere of alpha Ori. Atomic absorption features, primarily due to C I and Fe II are clearly seen in the G160M spectrum centered near 1655 A. These Fe II features are formed at temperatures that can occur only in the chromosphere of the star and are clearly not photospheric or circumstellar in origin.
The detection of high-redshift quasars

The detection of samples of high-redshift (i.e. distant) quasars provides direct information on the physical conditions existing when the Universe was only 10% of its present age. Quasars are the bright nuclei of certain galaxies and are the only astronomical sources that can currently be found in substantial numbers at redshifts z>2. It is probable that quasars are active for only a small proportion of the life of the host galaxy, in which case a substantial fraction of all galaxies must go through a quasar phase at some time in their history. Consequently quasars may be tracers of the galaxy population at high redshift, less active members of which are too faint for detailed study with present-day instrumentation. The main purpose of surveys for high-redshift quasars, then, is to map the evolution of the population, in luminosity and number density, back through the history of the Universe, thereby furnishing clues both to the nature of the quasar phenomenon itself and to the poorly understood process of how galaxies formed. Of special interest is the possibility of detecting the epoch of the birth of the quasar population. The authors summarise the optical and radio techniques employed in the detection of high-redshift (z>3) quasars and attempt to reconcile the contradictory claims in the literature concerning the evolution of their space density at the highest redshifts.
Outer radiation belt boundary location relative to the magnetopause: Implications for magnetopause shadowing

[1] Relativistic electron fluxes of the outer radiation belt often decrease rapidly in response to solar wind disturbances. The importance of the magnetopause shadowing (MPS) effect on such electron losses has yet to be quantified. If the MPS is essential for outer radiation belt electron losses, a close relationship between the outer edge of the outer belt and the magnetopause standoff distance is expected. Using GOES and THEMIS data, we examined earthward movement of the outer edge of the outer belt during electron loss events at geosynchronous orbit and its correlation with the magnetopause standoff distance. In events with significant earthward movement, we found a good correlation. There were no clear correlations in events without significant earthward movement, however. Comparing the observational results with a test particle simulation, the observed dependence between the outer edge and the magnetopause standoff distance is consistent with the MPS effect.
Gas detection based on optical correlation spectroscopy using a single light source

An alternative method of gas detection using optical correlation spectroscopy (OCS) has been investigated. A semiconductor optical amplifier (SOA) is employed to transmit broadband light through a reference and measurement cell containing the absorbing species, and the required 180° phase shift between the reference and measurement signal is achieved using an optical fibre delay line. The use of a single SOA light source reduces zero point drift errors that arise when two light sources are utilized and provides high compatibility with single mode optical fibre systems. A theoretical minimum detectable concentration of 0.15 ppm.m has been calculated and experimental results have been obtained for varying concentrations of acetylene (C2H2) gas at different pressures. The theoretical system response was determined using absorption data from the HITRAN database and compares well with the experimental results. Signal-to-noise ratio (SNR) analysis has been performed for our experimental system and an ideal system with minimal losses, an optimum filter and longer cell lengths.
SATELLITE EMISSION FEATURES IN THE LINE PROFILES OF SN 1987A

Approximately three weeks after the outburst of SN 1987A, satellite emission "bumps" suddenly appeared in the blue and red wings of Hα. In this paper optical and infrared spectroscopic observations obtained at Cerro Tololo Inter-American Observatory are analyzed in an attempt to better understand this event. These data show that comparable structure appeared in the profiles of several emission lines besides Hα, ruling out the possibility that the bumps were due to blends with lines of other elements. The velocities of the bumps in the rest frame of the supernova closely followed the velocity of the receding photosphere, which strongly suggests that the bump emission originated just above the photosphere. At the same time, a significant departure from spherical geometry for the emitting region is implied. The bumps appeared on the same day that the Hα flux began to track the bolometric light curve. It seems likely, therefore, that the appearance of the bumps was the first observable consequence of the arrival at the photosphere of energy associated with the radioactive decay of 56Ni and 56Co. For this to have occurred less that a month after outburst implies that significant amounts of radioactive material had been mixed outward into the hydrogen envelope.
INCLINATIONS AND AXIAL RATIOS OF SPIRAL AND IRREGULAR GALAXIES

Among galaxies with redshifts ≤ 500 km s-1^ spirals are found to have random orientations, whereas irregulars exhibit a highly significant excess of objects with 30deg^ <i< 60deg^. This effect may be explained by assuming that irregular galaxies are not well represented by spheroids of revolution with an intrinsic flattening of 0.2, which is the value that is generally used to calculate the inclinations of such objects. The observations suggest that typical dwarf irregular galaxies are triaxial objects with axis ratios of 1.0 : 0.9 : 0.4.
Influence of annealing on the magneto-resistance effect and microstructure in the two-step oxidized FeCo/AlOx/Co tunnel junction

The FeCo/AlOx/Co magnetic tunnel junction was fabricated using a two-step plasma oxidation technique. The tunnelling magneto-resistance ratio of the junction as-deposited was about 8.5%, and reached 14.0% after annealing at 200°C. Transmission electron microscopy, high-resolution electron microscopy and electron holography were used to study the microstructure of the junction. The enhancement of the magneto-resistance effect after annealing could be attributed to the uniformity of the barrier layer, the improvement of FM/I interfaces, and the deoxidization of the bottom ferromagnetic electrode.
Status of the CLIO project

The CLIO project involves the Cryogenic Laser Interferometer Observatory (CLIO) detector complex for gravitational wave detection and the Kamioka Laser Interferometric Strainmeter for the acquisition of geophysical data. CLIO has been constructed to demonstrate the feasibility of a future project, the Large-scale Cryogenic Gravitational wave Telescope (LCGT). It will utilize the low seismic and stable environment of the Kamioka mine as well as sapphire mirrors and suspension fibres at low temperature to reduce thermal noise. We designed CLIO to have a noise level limited by the thermal noise of sapphire mirrors and sapphire suspension fibres, which vary from 3 × 10−19 m Hz−1/2 at 300 K to 2 × 10−20 m Hz−1/2 at 20 K around 100 Hz. The strainmeter has already succeeded in monitoring the Earth's tidal motion with a strain sensitivity of 2 × 10−12. The seismic noise veto between these same-scale interferometers is expected to provide an effective means of data selection for the gravitational wave signal analysis, and the ground motion data obtained by the strainmeter will help to maintain the stable operation of CLIO.
A Note on Teaching Binomial Confidence Intervals

For constructing confidence intervals for a binomial proportion $p$, Simon (1996, Teaching Statistics) advocates teaching one of two large-sample alternatives to the usual $z$-intervals $\hat{p} \pm 1.96 \times S.E(\hat{p})$ where $S.E. (\hat{p}) = \sqrt{ \hat{p} \times (1 - \hat{p})/n}$. His recommendation is based on the comparison of the closeness of the achieved coverage of each system of intervals to their nominal level. This teaching note shows that a different alternative to $z$-intervals, called $q$-intervals, are strongly preferred to either method recommended by Simon. First, $q$-intervals are more easily motivated than even $z$-intervals because they require only a straightforward application of the Central Limit Theorem (without the need to estimate the variance of $\hat{p}$ and to justify that this perturbation does not affect the normal limiting distribution). Second, $q$-intervals do not involve ad-hoc continuity corrections as do the proposals in Simon. Third, $q$-intervals have substantially superior achieved coverage than either system recommended by Simon.
Probing adsorption sites on thin oxide films by dynamic force microscopy

Site specific atomically resolved dynamic force spectroscopy measurements were performed on a thin MgO film grown on Ag(001). The microscope is operated in ultrahigh vacuum at low temperature to ensure defined imaging condition, high stability, and drift reduction. Atomically resolved dynamic force microscopy images have been combined with site specific frequency shift versus distance measurements. The frequency shift is measured as a function of z and the lateral displacement. With these measurement characteristics the authors are currently probing inequivalent surface sites on thin MgO films to extract atomic-scale information on surface chemical reactivity and possible adsorption sites for metal atoms and small clusters.
Coagulation of grains in static and collapsing protostellar clouds

The wavelength dependence of extinction in the diffuse interstellar medium implies that it is produced by particles of dominant size of approximately 10(exp -5) cm. There is some indication that in the cores of dense molecular clouds, sub-micron grains can coagulate to form larger particles; this process is probably driven by turbulence. The most primitive meteorites (carbonaceous chondrites) are composed of particles with a bimodal size distribution with peaks near 1 micron (matrix) and 1 mm (chondrules). Models for chondrule formation that involve processing of presolar material by chemical reactions or through an accretion shock during infall assume that aggregates of the requisite mass could form before or during collapse. The effectiveness of coagulation during collapse has been disputed; it appears to depend on specific assumptions. The first results of detailed numerical modeling of spatial and temporal variations of particle sizes in presolar clouds, both static and collapsing, is reported in this article.
Modeling loss and backscattering in a photonic-bandgap fiber using strong perturbation

We use coupled-mode theory with strong perturbation to model the loss and backscattering coefficients of a commercial hollow-core fiber (NKT Photonics’ HC-1550-02 fiber) induced by the frozen-in longitudinal perturbations of the fiber cross section. Strong perturbation is used, for the first time to the best of our knowledge, because the large difference between the refractive indices of the two fiber materials (silica and air) makes conventional weak-perturbation less accurate. We first study the loss and backscattering using the mathematical description of conventional surface-capillary waves (SCWs). This model implicitly assumes that the mechanical waves on the core wall of a PBF have the same power spectral density (PSD) as the waves that develop on an infinitely thick cylindrical tube with the same diameter as the PBF core. The loss and backscattering coefficients predicted with this thick-wall SCW roughness are 0.5 dB/km and 1.1×10-10 mm-1, respectively. These values are more than one order of magnitude smaller than the measured values (20−30 dB/km and ~1.5×10-9 mm-1, respectively). This result suggests that the thick-wall SCW PSD is not representative of the roughness of our fiber. We found that this discrepancy occurs at least in part because the effect of the finite thickness of the silica membranes (only ~120 nm) is neglected. We present a new expression for the PSD that takes into account this finite thickness and demonstrates that the finite thickness substantially increases the roughness. The predicted loss and backscattering coefficients predicted with this thin-film SCW PSD are 30 dB/km and 1.3×10-9 mm-1, which are both close to the measured values. We also show that the thin-film SCW PSD accurately predicts the roughness PSD measured by others in a solid-core photonic-crystal fiber.
A large molecular cloud toward the SNR W50 and SS 433

The CO 1 . -->. 0 transition at 115 GHz has been mapped over an area of more than 6 deg/sup 2/ toward W50, the extended SNR surrounding the peculiar object SS 433 (l = 39/sup 0/.7, b = -2/sup 0/.3). W50 is found to lie at the end of a filamentary molecular cloud 4/sup 0/ long and 1/sup 0/ wide that closely matches a conspicuous dust lane on the Palomar Sky Survey; the cloud's kinematic distance is 2.2 +- 0.7 kpc, in agreement with the distance 2--3.3 kpc estimated for the SNR, and its mass is about 1.2 x 10/sup 5/ M/sub sun/. Though there is little evidence of star formation in the molecular filament, or evidence of an interaction between the filament and W50 (or SS 433), the positional coincidence of the two, their similar distance, and their displacement nearly two molecular scale heights from the plane all suggest a physical relationship or common origin. One possibility is that both the molecular filament and the stellar progenitor of W50 were ejected from a large active molecular complex lying in the plane at l = 40/sup 0/.
Ground-state Hyperfine Measurement in Laser Trapped Radioactive21Na

We have measured the ground-state hyperfine splitting between the ${3S}_{1/2} F=2,m=0$ and ${3S}_{1/2} F=1,m=0$ levels of ${}^{21}\mathrm{Na}. $ The measurement was performed with microwave spectroscopy on 40 000 radioactive ${}^{21}\mathrm{Na}$ atoms ${(t}_{1/2}=22 \mathrm{sec})$ collected in a magneto-optical trap on-line at the 88-in cyclotron at LBNL. The transition was excited with microwaves directed at the atoms and detected with resonant probe fluorescence light. The splitting ${\ensuremath{\nu}}_{\mathrm{HFS}}$ in a zero magnetic field was determined to be 1 906 471 870\ifmmode\pm\else\textpm\fi{}200 Hz.
Quasi-soliton propagation along a dispersion-profiled fibre using second-order moment theory

We show, through second order moment theory, the existence of a new regime of self-similar chirped-solitary wave in an appropriately dispersion-profiled fibre. This study completes the concept of quasi-solitons introduced by Kumar and Hasegawa. Theory reveals the existence of an invariant relation respected by quasi-solitons. This invariant relation can be fully recovered by the usual variational approach of the non-linear Schroedinger equation (NLS) and it can be used to study non-linear pulse propagation in constant dispersion optical fibers and ultimately for dispersion management. The work has been carried out for the lossless as well as for the lossy case.
Calculation of Critical Values for Somerville's FDR Procedures

A Fortran 95 program has been written to calculate critical values for the step-up and step-down FDR procedures developed by Somerville (2004). The program allows for arbitrary selection of number of hypotheses, FDR rate, one- or two-sided hypotheses, common correlation coefficient of the test statistics and degrees of freedom. An MCV (minimum critical value) may be specified, or the program will calculate a specified number of critical values or steps in an FDR procedure. The program can also be used to efficiently ascertain an upper bound to the number of hypotheses which the procedure will reject, given either the values of the test statistics, or their p values. Limiting the number of steps in an FDR procedure can be used to control the number or proportion of false discoveries (Somerville and Hemmelmann 2007). Using the program to calculate the largest critical values makes possible efficient use of the FDR procedures for very large numbers of hypotheses.
Coherent Gyromagnetic Emission as a Radiation Mechanism

The properties of coherent gyromagnetic emission of radiation which can escape from a source of astrophysical interest by a bi-Maxwellian distribution of nonrelativistic electrons (thermal velocities P 1.0 C and PII 0 c, and streaming velocity p, c) are considered. It is found that: (1) Coherent emission occurs only for Pio ;0;. PliO, and only for a more extreme anisotropy for waves close to their cutoff frequencies. (2) Coherent emission in the x-mode at the second harmonic, i.e. at OJ "'" 2Qe > OJp , is the dominant process except for p, > OJ~/Q; when coherent emission in the x-mode at he first harmonic, i.e. at OJ ~ Q. }> OJp , is possible and dominates. It is argued that these results are not strongly dependent on the choice of distribution function. It is pointed out that the use of the quasilinear equations can be justified in any astrophysical context but that the above properties apply even when the quasilinear treatment is not valid. Limitations imposed on the mechanism by the presence of absorption in the thermal plasma and by competing instabilities are shown to be relevant except for emission in the x-mode at the first harmonic.
Depth imaging with multiples

Depth imaging with multiples is a prestack depth migration method that uses multiples as the signal for more accurate boundary mapping and amplitude recovery. The idea is partially related to model‐based multiple‐suppression techniques and reverse‐time depth migration. Conventional reverse‐time migration uses the two‐way wave equation for the backward wave propagation of recorded seismic traces and ray tracing or the eikonal equation for the forward traveltime computation (the excitation‐time imaging principle). Consequently, reverse‐time migration differs little from most other one‐way wave equation or ray‐tracing migration methods which expect only primary reflection events. Because it is almost impossible to attenuate multiples without degrading primaries, there has been a compelling need to devise a tool to use multiples constructively in data processing rather than attempting to destroy them. Furthermore, multiples and other nonreflecting wave types can enhance boundary imaging and amplitude recovery.
Evaluating the dose effects of a longitudinal micro-CT study on pulmonary tissue in C57BL/6 mice

Background: Micro-computed tomography offers numerous advantages for small animal imaging, including the ability to monitor the same animals throughout a longitudinal study. However, concerns are often raised regarding the effects of x-ray dose accumulated over the course of the experiment. In this study, we scan C57BL/6 mice multiple times per week for six weeks, to determine the effect of the cumulative dose on pulmonary tissue at the end of the study. Methods/Results: C57BL/6 male mice were split into two groups (irradiated group=10, control group=10). The irradiated group was scanned (80kVp/50mA) each week for 6 weeks; the weekly scan session had three scans. This resulted in a weekly dose of 0.84 Gy, and a total study dose of 5.04 Gy. The control group was scanned on the final week. Scans from weeks 1 and 6 were reconstructed and analyzed: overall, there was no significant difference in lung volume or lung density between the control group and the irradiated group. Similarly, there were no significant differences between the week 1 and week 6 scans in the irradiated group. Histological samples taken from excised lung tissue also showed no evidence of inflammation or fibrosis in the irradiated group. Conclusion: This study demonstrates that a 5 Gy x-ray dose accumulated over six weeks during a longitudinal micro-CT study has no significant effects on the pulmonary tissue of C57BL/6 mice. As a result, the many advantages of micro- CT imaging, including rapid acquisition of high-resolution, isotropic images in free-breathing mice, can be taken advantage of in longitudinal studies without concern for negative dose-related effects.