Miracle-dz/UniFAR-FTUs huggingface dataset:
Sensitivity of the Track and Intensity Forecasts of Typhoon Megi (2010) to Satellite-Derived Atmospheric Motion Vectors with the Ensemble Kalman Filter

AbstractIn this study, sensitivities of the track and intensity forecasts of Typhoon Megi (2010) to the Cooperative Institute for Meteorological Satellite Studies (CIMSS) University of Wisconsin satellite atmospheric motion vector (AMV) dataset are examined. Assimilation of the CIMSS AMV dataset using the local ensemble transform Kalman filter implemented in the Weather Research and Forecasting model shows that the AMV data can significantly improve the track forecast of Typhoon Megi, especially the sharp turn from west-northwest to north after crossing the Philippines. By broadening the western Pacific subtropical high to the west, the AMV data can help reduce the eastward bias of the track, thus steering the storm away inimical shear environment and facilitating its subsequent development.Further sensitivity experiments with separated assimilation of the low- to midlevel (800–300 hPa) and upper-level (300–100 hPa) AMV winds reveal that, despite the sparse distribution of the low-level AMV winds with mos.
Polarization Variability among Wolf-Rayet Stars. VI. Linear Polarimetry of the Eclipsing Binary V444 Cygni

Precision broad-band blue light monitoring in linear polarization of the bright Cygnus W-R + O system V444 Cyg is reported. Analysis of the data yields an orbital inclination i = 78.5 deg, in good agreement with previous estimates based on polarimetry and on the analysis of light curves. In addition, V444 Cyg shows rapid polarimetric modulation around phase 0.5, when the O star companion eclipses the scattering electrons located primarily in the dense inner W-R wind. Simple modeling of the polarization eclipse based on a spherical electron envelope around the W-R star yields a satisfactory fit to the data. This model also supports the small value of the W-R core radius previously proposed by other authors. 35 refs.
Interpreting ~1 Hz magnetic compressional waves in Mercury's inner magnetosphere in terms of propagating ion‐Bernstein waves

We show that ~1 Hz magnetic compressional waves observed in Mercury's inner magnetosphere could be interpreted as ion‐Bernstein waves in a moderate proton beta ~0.1 plasma. An observation of a proton distribution with a large planetary loss cone is presented, and we show that this type of distribution is highly unstable to the generation of ion‐Bernstein waves with low magnetic compression. Ray tracing shows that as these waves propagate back and forth about the magnetic equator; they cycle between a state of low and high magnetic compression. The group velocity decreases during the high‐compression state leading to a pileup of compressional wave energy, which could explain the observed dominance of the highly compressional waves. This bimodal nature is due to the complexity of the index of refraction surface in a warm plasma whose upper branch has high growth rate with low compression, and its lower branch has low growth/damping rate with strong compression. Two different cycles are found: one where the compression maximum occurs at the magnetic equator and one where the compression maximum straddles the magnetic equator. The later cycle could explain observations where the maximum in compression straddles the equator. Ray tracing shows that this mode is confined within ±12° magnetic latitude which can account for the bulk of the observations. We show that the Doppler shift can account for the difference between the observed and model wave frequency, if the wave vector direction is in opposition to the plasma flow direction. We note that the Wentzel‐Kramers‐Brillouin approximation breaks down during the pileup of compressional energy and that a study involving full wave solutions is required.
A class of precompact sets in Banach spaces.

The vector spaces used here are defined on the field K of the real or complex numbers. If <£, F) is a dual pair, we denote by a (E, F), (E, F) and (E, F) the weak, the strong and the Mackey topologies on E, respectively. If G is a Banach space, G' its topological dual, € G' and u € G', we denote by \ \ x \ \ the norm of in G and || u || = sup{| u(y) | : y € G', || y \\ ̂ 1}. If E is a locally convex space with the Z topology and A is a subset of E, we denote by A[Z] the set A equipped with the topology induced by Z. If S is a bounded absolutely convex set in a locally convex space E, then EB is the linear hüll of ß, with the norm associated to B. Let E[ll] and F[%$] be separated locally convex spaces. Let A and B be two subsets of E[M] and . F[35], respectively. We say that A [H] and 5[SS] are topologically isomorphic if there exists an algebraical isomorphism f of the linear hüll of A onto the linear hüll of JB, so that the restriction of f to A is a homeomorphism of A [U] onto
Greek fricatives: Inferring articulation from F2 at vowel onset

Fricative consonants are produced with a narrow constriction in the vocal tract. According to the acoustic theory of speech production (Fant, 1960), fricatives are characterized by spectral prominences corresponding to the natural frequencies of the cavity anterior to the constriction. The spectral characteristics may also be modified by acoustic coupling of the noise source to the cavity behind the constriction (Stevens, 1998). In addition to the defining acoustic attributes, other articulatory gestures may be added to enhance the perceptual saliency of the fricatives (Stevens, 1989). This study examines the second formant frequency (F2) at the onset of a vowel following a fricative as an indication of tongue body position, a potential enhancing gesture for fricatives. F2 measurements were obtained from a database of 1950 tokens including all ten Greek fricatives (five places of articulation, two voicing categories) produced in five vowel contexts by 25 speakers. The results indicate highest F2 for palat.
Acoustics of gas‐bearing sediments I. Background

Acoustical properties of water saturated and gassy sediments are observed to be significantly different. The present state of knowledge of the acoustical properties of saturated sediments, gassy water, and gassy sediments is reviewed. The dynamics of bubbles in water and in various solid materials, including sediments, are experimentally examined in a companion paper. Pulsation resonance is exhibited by the bubbles in all materials examined. Predictions of bubble resonance frequency and damping are shown to agree with the measurements. Equations for sound speed and attenuation, based on the model of resonating gas bubbles, are shown to agree with published measurements in gassy sediments. Parameters required for predicting gassy sediment acoustical properties are identified. Ranges of values of these parameters for various sediments are discussed.
A Highly Reddened Star Cluster Embedded in the Galactic Plane

We found a cluster of early-type star candidates embedded in the Galactic plane by using optical to near-infrared broadband imaging. The observed region is around the 10 highly reddened stars found as a possible new and very remote open cluster by Stephenson. The 10 stars are identified as red supergiants, and several similar stars are newly found in our images. Furthermore, 25 early-type star candidates suffering visual extinction of AV ∼ 11.2 have been identified from various color-magnitude and color-color diagrams. These stars are likely to make a star cluster, and we estimate its age and distance to be ∼107.7 yr and ∼1.5 kpc, respectively.
Axisymmetric wakes behind a slender body including zero-momentum configurations

An experimental investigation of turbulent axisymmetric wakes including the zero‐momentum case was carried out. Mean and fluctuation velocity profiles were measured and self‐similar profiles were observed that decayed very rapidly when the momentum was adjusted to be zero. The wake behavior was found to be sensitive to any small mismatch of momentum and the relaxation zone strongly depended on the intensity and scale of the turbulence in the initial wake.
A subauroral and mid-latitude view of substorm activity

A substorm period near 0900 UT on January 2, 1971, provided both new and confirming evidence of mid-latitude and subauroral phenomena associated with magnetospheric substorm activity. Several of the principal ground and/or balloon observations were made near L = 4 at the conjugate stations Siple, Antarctica, and Roberval, Canada. Satellite data were obtained from ATS 5, positioned at synchronous orbit roughly 2 hours to the west of the Siple-Roberval meridian. A key feature of the substorm activity was the previously reported observation of correlated bursts of X rays and VLF noise. It has earlier been concluded that the VLF bursts and associated particle precipitation events were ‘triggered’ by whistlers entering the magnetosphere at L ∼ 4 outside but near the plasmapause. During the substorm period a widespread VLF phase anomaly (previously reported) was observed on subionospheric paths extending within the plasmasphere to L ∼ 2.5 and over much of North America. Conjugate ULF observations near L = 4 revealed enhancements of noise power in the 8- to 128-s period range at times of individual substorm intensifications and also a large increase in noise power during the period of correlated X ray and VLF burst activity. Conjugate VLF observations revealed a series of noise bands at frequencies below 3 kHz, with durations of the order of 30 min and center frequencies generally rising with time. The onset of each band appeared to follow within less than 10 min a substorm intensification detected from ground magnetometers or ATS 5 energetic particle detectors. Cross-L inward drifts of whistler paths were observed in the outer plasmasphere during the substorm activity. The inferred westward electric field averaged about 0.35 mV/m during the hour before the observations of correlated X ray and VLF bursts. During this hour the plasmapause appears to have been displaced to a position slightly equatorward of Siple; in terms of resonance conditions along the field lines, the X ray detectors on the balloon over Siple were then in a favorable position to observe the results of magnetospheric wave-particle interactions involving electrons of energy greater than 30 keV. The various observed phenomena show promise of providing information on (1) the relations of ULF and VLF noise activity to the magnetospheric particle population at middle latitudes, (2) the injection and subsequent drift of low and medium energy electrons during substorms, and (3) enhanced particle precipitation deep within the plasmasphere during substorms.
Spin qubits in double and triple quantum dots

This thesis presents research on the initialization, control, and readout of electron spin states in gate defined GaAs quantum dots. The first three experiments were performed with Singlet-Triplet spin qubits in double quantum dots, while the remaining two experiments were performed with an Exchange-Only spin qubit in a triple quantum dot. The first experiment examines the relationship between a dynamic nuclear polarization (DNP) process and the increase in measured singlet return probability in a SingletTriplet qubit. We find that the DNP process creates an Overhauser field difference, ∆Bz, between dots, which enhances the relaxation of triplet states during the measurement. We propose a model which explains this relaxation mechanism, and find it in good agreement with the data. The second and third experiments investigate the effects of dynamical decoupling sequences on the Singlet-Triplet qubit. We demonstrate the preservation of singlet-triplet superpositions by interlacing qubit rotations with Carr-Purcell (CP) sequences. We test the preservation of a singlet state with different dynamical decoupling schemes, finding a maximum coherence time of T2 ∼ 80μs for the CP sequence. The coherence time is studied for a number of π-pulses in the CP sequence, yielding an exponential dependence on even numbers of π-pulses. This allowed us to estimate the functional form of the noise spectrum influencing the qubit. The fourth experiment studied the initialization, complete electrical control, and readout of an Exchange-only spin qubit in a triple quantum dot. We demonstrate over 75 qubit rotations at 47 GHz and create a method of measurement and state tomography,
The effects of leaving the EU on UK trade

This paper investigates the effect of the 2016 Brexit referendum and the Trade and Cooperation Agreement (TCA) signed by the UK and the EU in December 2020 on UK-EU trade in goods up to December 2021. The 2016 referendum introduced uncertainty, but new trade barriers between the UK and the EU were not put in place until the new agreement, the TCA, entered into force in January 2021. Using a set of different econometric techniques, and looking up to the end of the first year of the implementation of the TCA, we find no evidence that the 2016 referendum had any impact on aggregate UK-EU trade. On the other hand, our results show that the TCA reduced UK trade with the EU, but differentially for exports and imports. After a sharp drop of around 40% in January 2021, UK exports to the EU quickly recovered in the following months. This pattern of recovery was not the case for UK imports from the EU, which were negatively impacted throughout of 2021, with a cumulative loss over the first year of implementation between -24% and -27%. We find evidence that a plausible explanation for these differential effects is the relative importance of the EU market for UK firms, in comparison to the importance of the UK market for EU firms.
On the internal structure of starless cores - I. Physical conditions and the distribution of CO, CS, N$\mathsf{_2}$H$\mathsf{^+}$, and NH$\mathsf{_3}$ in L1498 and L1517B

We have characterized the physical structure and chemical composition of two close-to-round starless cores in Taurus-Auriga, L1498 and L1517B. Our analysis is based on high angular resolution observations in at least two transitions of NH3 ,N 2H + ,C S, C 34 S, C 18 O, and C 17 O, together with maps of the 1.2 mm continuum. For both cores, we derive radial profiles of constant temperature and constant turbulence, together with density distributions close to those of non-singular isothermal spheres. Using these physical conditions and a Monte Carlo radiative transfer model, we derive abundance profiles for all species and model the strong chemical differentiation of the core interiors. According to our models, the NH3 abundance increases toward the core centers by a factor of several (≈5) while N2H + has a constant abundance over most of the cores. In contrast, both C 18 O and CS (and isotopomers) are strongly depleted in the core interiors, most likely due to their freeze out onto grains at densities of a few 10 4 cm −3 . Concerning the kinematics of the dense gas, we find (in addition to constant turbulence) a pattern of internal motions at the level of 0.1 km s −1 . These motions seem correlated with asymmetries in the pattern of molecular depletion, and we interpret them as residuals of core contraction. Their distribution and size suggest that core formation occurs in a rather irregular manner and with a time scale of a Myr. A comparison of our derived core properties with those predicted by supersonic turbulence models of core formation shows that our Taurus cores are much more quiescent than representative predictions from these models. In two appendices at the end of the paper we present a simple and accurate approximation to the density profile of an isothermal (Bonnor-Ebert) sphere, and a Monte Carlo-calibrated method to derive gas kinetic temperatures using NH3 data.
The Einstein /HEAO 2/ X-ray Observatory

The Einstein (HEAO 2) X-ray Observatory, launched in 1978, includes a fully imaging focusing X-ray telescope with an angular resolution of a few arc sec, a field of view of up to one deg, and a sensitivity several hundred times greater than previously available in any X-ray astronomy experiment. A high-resolution imager, an imaging proportional counter, a focal plane crystal spectrometer, and a monitor proportional counter are among the principal instruments on board the Einstein X-ray Observatory. About 20% of the total effective observing time in the first year of the X-ray astronomy experiment has been reserved for guest observers.
Steps toward the Hubble constant. VIII - The global value

The problem of determining the global Hubble constant is approached by using two distance indicators whose dispersion in absolute magnitude is small, and hence which are virtually free of the Malmquist bias. New data are presented on the mean absolute-magnitude of the brightest individual red and blue supergiant stars in very nearby galaxies, calibrated relative to the Cepheids. The results are used to calibrate the maximum absolute blue magnitude for two well-observed Type I supernovae (SNe I). The velocity-relative distance diagram for 16 SNe I with known maximum apparent blue magnitudes is then calibrated using distances for IC 4182 and NGC 4214, with the result that the global Hubble constant equals 50 + or - 7 km per second per megaparsec. The result is compared with the known age of globular clusters in the Galaxy to show that the cosmological and the evolutionary time scales now closely agree.
Direct and indirect adaptive integral line‐of‐sight path‐following controllers for marine craft exposed to ocean currents

We present a direct and an indirect nonlinear adaptive path‐following controller for marine craft based on a line‐of‐sight guidance principle used by ancient navigators. The control laws are implemented using hydro‐acoustic relative velocity measurements as opposed to absolute velocity measurements. For this purpose, a kinematic model for relative velocity in amplitude‐phase form is derived. The first contribution is an adaptive indirect controller based on a disturbance observer designed for estimation and compensation of ocean currents. The equilibrium points of the cross‐track and parameter estimation errors are proven to be globally κ exponentially stable. This guarantees that the estimated drift term converges to its true value exponentially. The observer is used in conjuncture with a control law to obtain asymptotic tracking and path following in the presence of ocean currents. The second contribution is a direct adaptive integral line‐of‐sight controller for path following. Global convergence of the cross‐track error is proven by using Barbălat's lemma, which ensures that the parameter estimation error is bounded. Both methods can be applied to the horizontal‐plane motion of surface vessels and autonomous underwater vehicles. An autonomous underwater vehicle case study is included to verify the results. Copyright © 2015 John Wiley & Sons, Ltd.
Theory of Vortex Sound

Physical arguments are followed by mathematical developments to show how aerodynamic sound is generated as a result of the movement of vortices, or of vorticity, in an unsteady fluid flow. Changes in circulation or area of a vortex ring give rise to a dipole sound field, the former being illustrated by oscillating flow about a fixed sphere, and the latter by a simple model for the aeolian tone attributable to the stretching of vortex rings. Because in a free flow there can be no change of the total vortex strength (circulation times area), there is no net dipole strength, but each moving element of vorticity still causes local dipolelike flow; each element of moving vorticity acts with some equal and opposite movement elsewhere in the flow so that together they form an oblique quadrupole, although the total effect must be reducible to an assembly of lateral quadrupoles. A cardinal result is that the vorticity in a slightly compressible fluid can be considered to induce the whole flow field, both the hydro.
STUDY OF INELASTIC SPECTRA WITH HIGH DAMPING

A statistical study of yield spectra with high damping is presented. A set of 10 earthquake records is used as input ground motions for elastoplastic single degree of freedom systems with damping ratios from 10% to 50%. Ductility ratios considered range from 1 to 6. From the statistics of the response spectra, parameters for constructing design spectra are derived and procedures described. Average effect of increasing damping on spectral response is presented.
Bidirectional solar wind electron heat flux events

Normally the ≳ 80-eV electrons which carry the solar wind electron heat flux are collimated along the interplanetary magnetic field (IMF) in the direction pointing outward away from the sun. Occasionally, however, collimated fluxes of ≳ 80-eV electrons are observed traveling both parallel and antiparallel to the IMF. Here we present the results of a survey of such bidirectional electron heat flux events as observed with the plasma and magnetic field experiments aboard ISEE 3 at times when the spacecraft was not magnetically connected to the earth's bow shock. The onset of a bidirectional electron heat flux at ISEE 3 usually signals spacecraft entry into a distinct solar wind plasma and field entity, most often characterized by anomalously low proton and electron temperatures, a strong, smoothly varying magnetic field, a low plasma beta, and a high total pressure. Significant field rotations often occur at the beginning and/or end of bidirectional heat flux events, and, at times, the large field rotations characteristic of “magnetic clouds” are present. Approximately half of all bidirectional heat flux events are associated with and follow interplanetary shocks, while the other events have no obvious shock associations. When shock associated, the delay from shock passage typically is ∼13 hours, corresponding to a radial separation of ∼0.16 AU. Independent of any shock association, bidirectional heat flux events typically are ∼0.13 AU thick in the radial direction, although considerable variability is evident from one event to another. Near solar activity maximum, bidirectional heat flux events occurred at a rate of ∼3 per month, and the solar wind electron heat flux was bidirectional ∼5% of the time. Bidirectional heat flux events often contain strong out-of-the-ecliptic field components and thus can be effective in producing geomagnetic disturbances. This is particularly true for shock-associated events where the intrinsically strong fields in the leading portions of the events are amplified by compression in transit from the sun and where strong out-of-the-ecliptic field components resulting from compression and draping of the ambient field are often present within the shocked plasma immediately ahead. Consistent with previous work we interpret the bidirectional heat flux as evidence for a closed field topology in interplanetary space. Further, we suggest that these events are one of the more prominent signatures of coronal mass ejection events in the solar wind at 1 AU.
Effects of two-dimensional topographies using the discrete wavenumber-boundary integral equation method in P-SV cases

The effect of topography on surface motion is studied in the case of incident P and SV waves and in presence of an explosive source. The discrete wavenumber‐boundary integral equation method is formulated for this case and is applied to the problem of diffraction of an elastic wave field by a ridge‐shaped topography. The amplitude of the scattered field, which mostly consists of surface P waves and Rayleigh waves, is strongly dependent on the steepness of the topography. The generation of surface waves by an explosion located in the vicinity of the ridge topography is studied and an increase in Rayleigh wave amplitude and a broadening of the Rayleigh pulse when the explosion occurs within the ridge is found.