Miracle-dz/UniFAR-FTUs huggingface dataset:
Dense gas in nearby galaxies. XVI. The nuclear starburst environment in NGC 4945

A multi-line millimeter-wave study of the nearby starburst galaxy NGC4945 has been carried out using the Swedish-ESO Submillimeter Telescope (SEST). The study covers the frequency range from 82 GHz to 354 GHz and includes 80 transitions of 19 molecules. 1.3 mm continuum data of the nuclear source are also presented. An analysis of CO and 1.3 mm continuum fluxes indicates that the conversion factor between H-2 column density and CO J = 1-0 integrated intensity is smaller than in the galactic disk by factors of 5-10. A large number of molecular species indicate the presence of a prominent high density interstellar gas component characterized by n(H2) similar to 10(5) cm(-3). Some spectra show Gaussian profiles. Others exhibit two main velocity components, one at similar to450 km s(-1), the other at similar to710 km s(-1). While the gas in the former component has a higher linewidth, the latter component arises from gas that is more highly excited as is indicated by HCN, HCO+ and CN spectra. Abundances of molecular species are calculated and compared with abundances observed toward the starburst galaxies NGC 253 and M 82 and galactic sources. Apparent is an "overabundance" of HNC in the nuclear environment of NGC4945. While the HNC/HCN J = 1-0 line intensity ratio is similar to0.5, the HNC/HCN abundance ratio is similar to1. From a comparison of K-a = 0 and 1 HNCO line intensities, an upper limit to the background radiation of 30 K is derived. While HCN is subthermally excited (T-ex similar to 8 K), CN is even less excited (Tex similar to 3-4 K), indicating that it arises from a less dense gas component and that its N = 2-1 line can be optically thin even though its N = 1-0 emission is moderately optically thick. Overall, fractional abundances of NGC 4945 suggest that the starburst has reached a stage of evolution that is intermediate between those observed in NGC 253 and M 82. Carbon, nitrogen, oxygen and sulfur isotope ratios are also determined. Within the limits of uncertainty, carbon and oxygen isotope ratios appear to be the same in the nuclear regions of NGC 4945 and NGC 253. High O-18/O-17, low O-16/O-18 and N-14/N-15 and perhaps also low S-32/S-34 ratios (6.4 +/- 0.3, 195 +/- 45, 105 +/- 25 and 13.5 +/- 2.5 in NGC 4945, respectively) appear to be characteristic properties of a starburst environment in which massive stars have had sufficient time to affect the isotopic composition of the surrounding interstellar medium.
Mass balance of the Lambert Glacier–Amery Ice Shelf system, East Antarctica: a comparison of computed balance fluxes and measured fluxes

Abstract We combine European Remote-sensing Satellite (ERS-1) radar altimeter surface elevations (Fricker and others, 2000) with six different accumulation distributions to compute balance fluxes for the Lambert Glacier–Amery Ice Shelf drainage system. These interpolated balance fluxes are compared with fluxes derived from in situ measurements of ice thickness and velocity at 73 stations of the Lambert Glacier basin traverse and at 11 stations further downstream, to assess the system’s state of balance. For the upstream line we obtain a range of imbalance estimates, from −23.8% to +19.9% of the observed flux, reflecting the sensitivity to the accumulation distributions. For some of the accumulation distributions the imbalance estimates vary significantly between different parts of the line. Imbalance estimates for the downstream line range from −17.7% to +70.2%, with four of the estimates exceeding +30%, again reflecting the sensitivity of the result to input accumulation, and strongly suggesting that the mass balance of the region between the two lines is positive. Our results confirm the importance of accurate estimates of accumulation in ice-sheet mass-balance studies. Furthermore, they suggest that it is not possible to accurately determine the state of balance of large Antarctic drainage basins on the basis of currently available accumulation distributions.
Skewers

The skewer of a pair of skew lines in space is their common perpendicular. To configuration theorems of plane projective geometry involving points and lines (such as Pappus or Desargues) there correspond configuration theorems in space: points and lines in the plane are replaced by lines is space, the incidence between a line and a point translates as the intersection of two lines at right angle, and the operations of connecting two points by a line or by intersecting two lines at a point translate as taking the skewer of two lines. These configuration theorems hold in elliptic, Euclidean, and hyperbolic geometries. This correspondence principle extends to plane configuration theorems involving polarity. For example, the theorem that the three altitudes of a triangle are concurrent corresponds to the Petersen-Morley theorem that the common normals of the opposite sides of a space right-angled hexagon have a common normal. We define analogs of plane circles (they are 2-parameter families of lines in space) and extend the correspondence principle to plane theorems involving circles. We also discuss the skewer versions of the Sylvester problem: given a finite collection of pairwise skew lines such that the skewer of any pair intersects at least one other line at right angle, do all the line have to share a skewer? The answer is positive in the elliptic and Euclidean geometries, but negative in the hyperbolic one.
Ballot Initiatives and Wildlife Management Policy Change in Two Western States

In the wildlife policy arena ballot initiatives have been used increasingly over the past two decades to wrest control of policy from legislators and bureaucrats. This trend has led to dramatic changes in policy as professionals are forced to adapt to changing political winds. I use a model of policy change developed by Baumgartner and Jones to examine how the wildlife policy arena has changed in recent years by ballot initiatives. Case studies involving trapping in California and Colorado are examined to determine whether the wildlife establishment prevails is affected by the success of opponents in altering policy image. Over the past decade and a half perhaps no wildlife management tool at the state level has come under greater criticism than use of the steel-jawed, leg-hold trap. Eight states—Arizona, California, Colorado, Florida, Massachusetts, New Jersey, Rhode Island, and Washington—have outlawed the use of these supposedly cruel devices. In all states but Florida, New Jersey, and Rhode Island, voters—not state legislatures—approved the bans. Advocates of trapping bans have spent millions on ballot issues, usually effectively overwhelming federal and state wildlife agencies which argue that the use of the ballot box makes a mockery of the professional decision-making superiority of wildlife managers. The ferocity of the debate is rooted in differing perspectives of the safety of traps to capture predators of livestock. The leg hold trap itself is comprised of two jaws, a spring, and a trigger. When the animal steps on the trigger the trap
Black holes in the limiting curvature theory of gravity

We discuss a recently proposed limiting curvature theory of gravity and its application to the problem of singularities inside black holes. In this theory the growth of the curvature is suppressed by specially chosen inequality constraints included in the gravity action. We consider a case of a spherically symmetric four dimensional black hole and demonstrated that imposed curvature constraints modify a solution in the black hole interior. Instead of forming the curvature singularity the modified metric describes a space which is exponentially expanding in one direction and oscillating the other two directions. The spacetime is complete and its polynomial curvature invariants are uniformly bounded.
K-Ar ages of Cainozoic Volcanic Suites, Bowen-St. Lawrence Hinterland, Northern Queensland (with some implications for petrologic models)

Abstract Thirty K‐Ar dates on Cainozoic volcanic rocks lying at the north end of the Bowen Basin suggest that several episodes of volcanism took place at major structural weaknesses. The oldest volcanism (ca 54 m.y.) was located outside the basin structure. The main volcanism (Nebo and East Clermont Provinces) extended from early Oligocene (34–35 m.y.) to mid‐Cainozoic time (21–22 m.y.? ). Isolated Pliocene activity is tentatively suggested by dates on Mt St Martin (ca 3 m.y.). Dating of the Nebo central volcano (31–33 m.y.) supports the model of Wellman & McDougall, with volcanic activity related to migration of Australia northwards over a mantle magma source. Consideration of the Nebo dates with those of other central volcanoes in north Queensland, suggests that central felsic activity was surrounded by broad zones of peripheral eruptives, petrologically zoned from outer undersaturated basalts to inner saturated basalts. These zones (super provinces) delineate the size and profile of underlying magma sou.
Decision support systems for environmental flows: Lessons from Southern Africa

Abstract The decision by a number of countries to re‐engage with large dams creates an obligation to ensure that the attendant environmental and social consequences are dealt with adequately. In this regard, the key challenges for the future are the assessment and management of downstream environmental and social impacts. The paper examines these issues in the context of southern Africa, particularly the Lesotho Highlands Water Project. It examines the ways in which Environmental Flows can affect the environment and the livelihoods of riparians, the need to make trade‐offs between different uses of the water, and the difficulties of making trade‐offs if the values of stakeholders regarding water use are not supported by a legal framework. The paper highlights the need to undertake environmental flow work early in the project cycle as part of the Environmental Impact Assessment, and the need to integrate environmental flow factors into the project's economic analysis. It explores the financial trade‐offs that are implicit in environmental flow work, the need for a multi‐disciplinary team to carry out the work, and the need for a transparent decision framework. Finally, the importance of establishing a decision support system for use during the operational phases of the project is highlighted.
Characterization of Brownian Gibbsian line ensembles

In this paper we show that a Brownian Gibbsian line ensemble is completely characterized by the finite-dimensional marginals of its top curve, i.e. the finite-dimensional sets of the its top curve form a separating class. A particular consequence of our result is that the Airy line ensemble is the unique Brownian Gibbsian line ensemble, whose top curve is the Airy$_2$ process.
ALMA and VLA measurements of frequency-dependent time lags in Sagittarius A*: evidence for a relativistic outflow

Context. Radio and mm-wavelength observations of Sagittarius A* (Sgr A*), the radio source associated with the supermassive black hole at the center of our Galaxy, show that it behaves as a partially self-absorbed synchrotron-emitting source. The measured size of Sgr A* shows that the mm-wavelength emission comes from a small region and consists of the inner accretion flow and a possible collimated outflow. Existing observations of Sgr A* have revealed a time lag between light curves at 43 GHz and 22 GHz, which is consistent with a rapidly expanding plasma flow and supports the presence of a collimated outflow from the environment of an accreting black hole. Aims. Here we wish to measure simultaneous frequency-dependent time lags in the light curves of Sgr A* across a broad frequency range to constrain direction and speed of the radio-emitting plasma in the vicinity of the black hole. Methods. Light curves of Sgr A* were taken in May 2012 using ALMA at 100 GHz using the VLA at 48, 39, 37, 27, 25.5, and 19 GHz. As a result of elevation limits and the longitude di erence between the stations, the usable overlap in the light curves is approximately four hours. Although Sgr A* was in a relatively quiet phase, the high sensitivity of ALMA and the VLA allowed us to detect and fit maxima of an observed minor flare where flux density varied by 10%. Results. The fitted times of flux density maxima at frequencies from 100 GHz to 19 GHz, as well as a cross-correlation analysis, reveal a simple frequency-dependent time lag relation where maxima at higher frequencies lead those at lower frequencies. Taking the observed size-frequency relation of Sgr A* into account, these time lags suggest a moderately relativistic (lower estimates: 0.5c for two-sided, 0.77c for one-sided) collimated outflow.
Overview of the TREC 2019 Fair Ranking Track

The goal of the TREC Fair Ranking track was to develop a benchmark for evaluating retrieval systems in terms of fairness to different content providers in addition to classic notions of relevance. As part of the benchmark, we defined standardized fairness metrics with evaluation protocols and released a dataset for the fair ranking problem. The 2019 task focused on reranking academic paper abstracts given a query. The objective was to fairly represent relevant authors from several groups that were unknown at the system submission time. Thus, the track emphasized the development of systems which have robust performance across a variety of group definitions. Participants were provided with querylog data (queries, documents, and relevance) from Semantic Scholar. This paper presents an overview of the track, including the task definition, descriptions of the data and the annotation process, as well as a comparison of the performance of submitted systems.
Multiple Climate Signals Characterize Cassiope Mertensiana Chronologies for a Site on Mount Rainier, Washington, USA

This study investigates the nature and strength of the climate signals that characterize an alpine dwarf-shrub, Cassiope mertensiana (mountain bell heather). For the first time, we present six new C. mertensiana chronologies (two growth, two reproduction, 1963-2004; δ13C, δ18O, 1975-2005) based on 14 plants from a subalpine meadow site on Mount Rainier, Washington, USA. Correlation, factor, and multivariate regression analyses revealed that multiple and different climate factors control the chronologies. Annual growth and leaf production are controlled by previous- and current- year growing season and previous-year February temperature. Warm growing season temperatures positively influence soil nutrient uptake rates, while winter temperatures may temporally alter moisture distribution resulting in reduced plant growth. Annual flower bud production is controlled by previous and current-year mean summer, growing season, and annual dewpoint temperature. Annual flower production is controlled by current-year mean spring, summer, growing-season, and annual dewpoint temperature. Increased atmospheric moisture facilitates open stomata, higher photosynthetic activity, and increased reproduction. Previous-year growing season and annual dew-point temperature, fall relative humidity, and temperature control δ18O values, indicating the influence of stomatal conductance on evaporative enrichment. Previous-year spring dewpoint and annual maximum temperature control δ13C values, suggesting the values are a product of photosynthetic rate controlled by temperature or photon flux.
3D morphometry of valley networks on Mars from HRSC/MEX DEMs: Implications for climatic evolution through time

Martian valley networks have been identified mainly in the Noachian heavily cratered uplands. Eight dense branching valley networks were studied in Noachian terrains of Huygens, Newcomb and Kepler craters, south Tyrrhena Terra, and Thaumasia, in Hesperian terrains of Echus Plateau and west Eberswalde craters, and in Amazonian terrains of Alba Patera, using images and digital elevation models from the Mars Express High Resolution Stereo Camera to determine 2D and 3D morphometric parameters. Extracted geomorphic parameters show similar geometry to terrestrial valleys: drainage densities, organization from bifurcation ratios and lengths ratios, Hack exponent consistent with terrestrial values of ~0.6, and progressive deepening of valleys with increasing Strahler order. In addition, statistics on valley depths indicate a deeper incision of Noachian valleys compared to younger post‐Noachian valleys (<25 m for Amazonian ones compared to >100 m for Noachian ones), showing a strong difference in fluvial erosion. These characteristics show that dense Martian valley networks formed by overland flows in relation to a global atmospheric water cycle in Noachian epoch and confirm that the later stages of activity may be related to shorter duration of activity, distinct climatic conditions, and/or regional processes, or conditions.
Quantum Hyperbolic Invariants Of 3-Manifolds With PSL(2,C)-Characters

We construct {\it quantum hyperbolic invariants} (QHI) for triples $(W,L,\rho)$, where $W$ is a compact closed oriented 3-manifold, $\rho$ is a flat principal bundle over $W$ with structural group $PSL(2,\mc)$, and $L$ is a non-empty link in $W$. These invariants are based on the Faddeev-Kashaev's {\it quantum dilogarithms}, interpreted as matrix valued functions of suitably decorated hyperbolic ideal tetrahedra. They are explicitely computed as state sums over the decorated hyperbolic ideal tetrahedra of the {\it idealization} of any fixed {\it $\Dd$-triangulation}; the $\Dd$-triangulations are simplicial 1-cocycle descriptions of $(W,\rho)$ in which the link is realized as a Hamiltonian subcomplex. We also discuss how to set the Volume Conjecture for the coloured Jones invariants $J_N(L)$ of hyperbolic knots $L$ in $S^3$ in the framework of the general QHI theory.
The Spectral Bias of the Deep Image Prior

The "deep image prior" proposed by Ulyanov et al. is an intriguing property of neural nets: a convolutional encoder-decoder network can be used as a prior for natural images. The network architecture implicitly introduces a bias; If we train the model to map white noise to a corrupted image, this bias guides the model to fit the true image before fitting the corrupted regions. This paper explores why the deep image prior helps in denoising natural images. We present a novel method to analyze trajectories generated by the deep image prior optimization and demonstrate: (i) convolution layers of the an encoder-decoder decouple the frequency components of the image, learning each at different rates (ii) the model fits lower frequencies first, making early stopping behave as a low pass filter. The experiments study an extension of Cheng et al which showed that at initialization, the deep image prior is equivalent to a stationary Gaussian process.
Energetics Responses to Increases in Greenhouse Gas Concentration

Abstract Increasing greenhouse gas concentrations warm the troposphere. However, it is not clear whether this implies changes in the energetics. To study the energetics responses to CO2 increases, changes in the Lorenz energy cycle (LEC) are evaluated using output from the atmosphere–ocean ECHAM5/Max Planck Institute Ocean Model (MPI-OM). Equilibrium 2 × CO2 experiments and 10-yr transient experiments with 3% increase per year are analyzed. Globally, doubling of CO2 results in a decrease in the LEC strength—defined as the total conversion of available potential energy P into kinetic energy K—but also in an increase in the zonal-mean K. These global changes are a consequence of the strengthening of the LEC in the upper troposphere and the weakening of the cycle below. The two opposite responses result from the simulated warming pattern that shows the strongest warming in the upper tropical troposphere and in the lower troposphere at high latitudes. This warming structure causes changes in the horizontal te.
Dynamic light scattering measurements in the activated regime of dense colloidal hard spheres

We use dynamic light scattering and numerical simulations to study the approach to equilibrium and the equilibrium dynamics of systems of colloidal hard spheres over a broad range of densities, from dilute systems up to very concentrated suspensions undergoing glassy dynamics. We discuss several experimental issues (sedimentation, thermal control, non-equilibrium ageing effects, dynamic heterogeneity) arising when very large relaxation times are measured. When analyzed over more than seven decades in time, we find that the equilibrium relaxation time, τα, of our system is described by the algebraic divergence predicted by mode-coupling theory over a window of about three decades. At higher density, τα increases exponentially with distance to a critical volume fraction φ0, which is much larger than the mode-coupling singularity. This is reminiscent of the behavior of molecular glass-formers in the activated regime. We compare these results to previous work, carefully discussing crystallization and size polydispersity effects. Our results suggest the absence of a genuine algebraic divergence of τα in colloidal hard spheres.
A bootstrap procedure to select hyperspectral wavebands related to tannin content

Detection of hydrocarbons in plants with hyperspectral remote sensing is hampered by overlapping absorption pits, while the ‘optimal’ wavebands for detecting some surface characteristics (e.g. chlorophyll, lignin, tannin) may shift. We combined a phased regression with a bootstrap procedure to find wavebands related to the tannin content of fresh leaves, and compared the bands thus identified with the reflectance spectra of pure quebracho tannin. For both reflectance and derivative spectra, bands were identified that can be linked to known absorption features (1471, 1640, 1710, 2175 nm) or fall within the absorption regions identified from a reflectance curve of pure quebracho tannin. We also confirmed a previously reported link between tannin content and the derivative spectra around 800 nm. The study shows that by combining bootstrapping with phased regression it is possible to determine wavebands of which the reflectance is influenced by tannin.
Permutation Matrices and the Moments of their Characteristics Polynomials

In this paper, we are interested in the moments of the characteristic polynomial $Z_n(x)$ of the $n\times n$ permutation matrices with respect to the uniform measure. We use a combinatorial argument to write down the generating function of $E[\prod_{k=1}^pZ_n^{s_k}(x_k)]$ for $s_k\in\mathbb{N}$. We show with this generating function that $\lim_{n\to\infty}E[\prod_{k=1}^pZ_n^{s_k}(x_k)]$ exists exists for $\max_k|x_k|<1$ and calculate the growth rate for $p=2$, $|x_1|=|x_2|=1$, $x_1=x_2$ and $n\to\infty$. We also look at the case $s_k\in\mathbb{C}$. We use the Feller coupling to show that for each $|x|<1$ and $s\in\mathbb{C}$ there exists a random variable $Z_\infty^s(x)$ such that $Z_n^s(x)\overset{d}{\to}Z_\infty^s(x)$ and $E[\prod_{k=1}^pZ_n^{s_k}(x_k)]\to E[\prod_{k=1}^pZ_\infty^{s_k}(x_k)]$ for $\max_k|x_k|<1$ and $n\to\infty$.