The Relationship Between Molecular Gas and Star Formation in Low-Mass E/S0 Galaxies

We consider the relationship between molecular-gas and star-formation surface densities in 19 morphologically defined E/S0s with stellar mass <~ 4x10^10 M_sun, paying particular attention to those found on the blue sequence in color vs. stellar mass parameter space, where spiral galaxies typically reside. While some blue-sequence E/S0s must be young major-merger remnants, many low-mass blue-sequence E/S0s appear much less disturbed, and may be experiencing the milder starbursts associated with inner-disk building as spirals (re)grow. For a sample of eight E/S0s (four blue-, two mid-, and two red-sequence) whose CARMA CO(1-0), Spitzer MIPS 24um, and GALEX FUV emission distributions are spatially resolved on a 750pc scale, we find roughly linear relationships between molecular-gas and star-formation surface densities within all galaxies, with power law indices N = 0.6-1.9 (median 1.2). Adding 11 more blue-sequence E/S0s whose CO(1-0) emission is not as well resolved, we find that most of our E/S0s have global 1-8 kpc aperture-averaged molecular-gas surface densities overlapping the range spanned by the disks and centers of spiral galaxies. While many of our E/S0s fall on the same Schmidt-Kennicutt relation as local spirals, ~80% (predominantly on the blue sequence) are offset towards apparently higher molecular-gas star formation efficiency (i.e., shorter molecular gas depletion time). Possible interpretations of the elevated efficiencies include bursty star formation similar to that in local dwarf galaxies, H2 depletion in advanced starbursts, or simply a failure of the CO(1-0) emission to trace all of the molecular gas.Comment: ApJL, accepted, 16 pages with 3 color figures, 2 table

Numerical study of concrete-filled austenitic stainless steel CHS stub columns with high-strength steel inner tubes

[EN] A numerical modelling programme simulating the structural behaviour of concrete-filled double skin tubular (CFDST) stub columns with stainless steel outer tubes and high strength steel inner tubes is presented in this paper. The numerical model, which was developed using the finite element package ABAQUS, was initially validated against existing experimental results considering ultimate load, load-deflection histories and failure modes, with good agreement observed. Upon validation of the FE model, an extensive parametric study was undertaken whereby the cross-section slendernesses of the outer and inner tubes, the strength of the inner tube and the concrete grades were varied. These generated results together with the experimental data were then employed to assess the suitability of the design provisions of the European Standard EN 1994-1-1 and American Specification for concrete-filled tubes. Modifications to these design rules are also proposed, and a reduction factor (η) is suggested to account for the effective compressive strength in high strength concrete.Wang, F.; Young, B.; Gardner, L. (2018). Numerical study of concrete-filled austenitic stainless steel CHS stub columns with high-strength steel inner tubes. En Proceedings of the 12th International Conference on Advances in Steel-Concrete Composite Structures. ASCCS 2018. Editorial Universitat Politècnica de València. 343-350. https://doi.org/10.4995/ASCCS2018.2018.8273OCS34335

Food Preferences, Food Intake, and Growth of the F\u3csub\u3e1\u3c/sub\u3e Hybrid of Grass Carp ♀ X Bighead Carp ♂

Hybrid carp from the cross grass carp Ctenopharyngodon idella ♀ X bighead carp Aristichthys nobilis ♂ preferred filamentous algae and Najas guadalupensis over Ceratophyllum demersum. Medium-sized (273 g) and large hybrids (360 g) consumed more plant material and grew faster than small hybrids (77 g) at 14 and 22 C in aquaria. Aquarium data suggest that it will require at least twice as many hybrids as grass carp of the same size to obtain the same level of vegetation control

The CO-H2 conversion factor of diffuse ISM: Bright 12CO emission also traces diffuse gas

We show that the XCO factor, which converts the CO luminosity into the column density of molecular hydrogen has similar values for dense, fully molecular gas and for diffuse, partially molecular gas. We discuss the reasons of this coincidence and the consequences for the understanding of the interstellar medium.Comment: 5 pages, 1 PostScript figure. To be published in the proceedings of the Zermatt 2010 conference: "Conditions and impact of star formation: New results with Herschel and beyond". Uses EAS LaTeX macro

Functional Big-step Semantics

When doing an interactive proof about a piece of software, it is important that the underlying programming language’s semantics does not make the proof unnecessarily difficult or unwieldy. Both smallstep and big-step semantics are commonly used, and the latter is typically given by an inductively defined relation. In this paper, we consider an alternative: using a recursive function akin to an interpreter for the language. The advantages include a better induction theorem, less duplication, accessibility to ordinary functional programmers, and the ease of doing symbolic simulation in proofs via rewriting. We believe that this style of semantics is well suited for compiler verification, including proofs of divergence preservation. We do not claim the invention of this style of semantics: our contribution here is to clarify its value, and to explain how it supports several language features that might appear to require a relational or small-step approach. We illustrate the technique on a simple imperative language with C-like for-loops and a break statement, and compare it to a variety of other approaches. We also provide ML and lambda-calculus based examples to illustrate its generality

Time-based noise-shaping techniques for time-to-digital and analog-to-digital converters

In this dissertation, time-based signal processing techniques and their applications in oversampling and noise-shaping data converters are examined. These techniques demonstrate the ability to shift the burden of high performance analog circuits from the compressed voltage-domain to the augmented time-domain. First, the potential of high order noise-shaping and phase-domain feedback in time-to-digital converters (TDCs) is explored. A prototype phase reference, second-order continuous-time delta-sigma TDC for sensor applications was fabricated in 90nm CMOS and achieves 64 dB dynamic range in 1MHz signal bandwidth. Second, an ultra-high performance oscillator-based delta-sigma modulator architecture is investigated. The proposed circuit is a third-order continuous-time PLL-Based Delta-Sigma Modulator with simulated 77 dB SNDR in 40MHz signal bandwidth with OSR of 16, and is fabricated in 65nm CMOS

Environmental Regulation and Regional Economic Growth: An Input-Output Analysis of the Ohio Coal Mining Region

Exact date of working paper unknown