UNINTENDED CONSEQUENCES OF MARRIAGE PENALTY RELIEF: THE EFFECT ON THE MARRIED COUPLE\u27S CHOICE OF FILING STATUS

PANEL II: ASSESSING PROPOSED SOLUTIONS FORUM ON MARRIED WOMEN AND THE INCOME TAX: MARRIAGE PENALTIES AND MARRIAGE BONUSES OF THE 105 H CONGRES

Linearity Analysis and Efficiency Testing of The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) Science Cameras for Flight

To unveil the complexity of the solar atmosphere, measurement of the magnetic field in the upper chromosphere and transition region is fundamentally important, as this is where the forces transition from plasma to magnetic field dominated. Measurements of the field are also needed to elucidate the energy transport from the lower atmospheric regions to the corona beyond. Such an advance in heliospheric knowledge became possible with the first flight of the international solar sounding rocket mission, CLASP. For the first time, linear polarization was measured in Hydrogen Lyman-Alpha at 121.60 nm in September 2015. For linear polarization measurements in this emission line, high sensitivity is required due to the relatively weak polarization signal compared to the intensity. To achieve this high sensitivity, a low-noise sensor is required with good knowledge of its characterization, including linearity. This work presents further refinement of the linearity characterization of the cameras flown in 2015. We compared the current from a photodiode in the light path to the digital response of the detectors. Pre-flight CCD linearity measurements were taken for all three flight cameras and calculations of the linear fits and residuals were performed. However, the previous calculations included a smearing pattern and a digital saturation region on the detectors which were not properly taken into account. The calculations have been adjusted and were repeated for manually chosen sub-regions on the detectors that were found not to be affected. We present a brief overview of the instrument, the calibration data and procedures, and a comparison of the old and new linearity results. The CLASP cameras will be reused for the successor mission, CLASP2, which will measure the Magnesium II h & k emission lines between 279.45 nm and 280.35 nm. The new approach will help to better prepare for and to improve the camera characterization for CLASP2

Assembly line enzymology by multimodular nonribosomal peptide synthetases: the thioesterase domain of E. coli EntF catalyzes both elongation and cyclolactonization

BackgroundEntF is a 142 kDa four domain (condensation-adenylationpeptidyl carrier protein-thioesterase) nonribosomal peptide synthetase (NRPS) enzyme that assembles the Escherichia coli N-acyl-serine trilactone siderophore enterobactin from serine, dihydroxybenzoate (DHB) and ATP with three other enzymes (EntB, EntD and EntE). To assess how EntF forms three ester linkages and cyclotrimerizes the covalent acyl enzyme DHB-Ser-S-PCP (peptidyl carrier protein) intermediate, we mutated residues of the proposed catalytic Ser-His-Asp triad of the thioesterase (TE) domain.ResultsThe Ser1138→Cys mutant (kcat decreased 1000-fold compared with wild-type EntF) releases both enterobactin (75%) and linear (DHB-Ser)2 dimer (25%) as products. The HiResultThe Ser1138→Cys mutant (kcat decreased 1000-fold compared with wild-type EntF) releases both enterobactin (75%) and linear (DHB-Ser)2 dimer (25%) as products. The His1271→Ala mutant (kcat decreased 10,000-fold compared with wild-type EntF) releases only enterobactin, but accumulates both DHB-Ser-O-TE and (DHB-Ser)2-O-TE acyl enzyme intermediates. Electrospray ionization and Fourier transform mass spectrometry of proteolytic digests were used to analyze the intermediates.71→Ala mutant (kcat decreased 10,000-fold compared with wild-type EntF) releases only enterobactin, but accumulates both DHB-Ser-O-TE and (DHB-Ser)2-O-TE acyl enzyme intermediates. Electrospray ionization and Fourier transform mass spectrometry of proteolytic digests were used to analyze the intermediates.ConclusionsThese results establish that the TE domain of EntF is both a cyclotrimerizing lactone synthetase and an elongation catalyst for ester-bond formation between covalently tethered DHB-Ser moieties, a new function for chain-termination TE domains found at the carboxyl termini of multimodular NRPSs and polyketide synthases

Probing the extragalactic fast transient sky at minute timescales with DECam

Searches for optical transients are usually performed with a cadence of days to weeks, optimised for supernova discovery. The optical fast transient sky is still largely unexplored, with only a few surveys to date having placed meaningful constraints on the detection of extragalactic transients evolving at sub-hour timescales. Here, we present the results of deep searches for dim, minute-timescale extragalactic fast transients using the Dark Energy Camera, a core facility of our all-wavelength and all-messenger Deeper, Wider, Faster programme. We used continuous 20s exposures to systematically probe timescales down to 1.17 minutes at magnitude limits $g > 23$ (AB), detecting hundreds of transient and variable sources. Nine candidates passed our strict criteria on duration and non-stellarity, all of which could be classified as flare stars based on deep multi-band imaging. Searches for fast radio burst and gamma-ray counterparts during simultaneous multi-facility observations yielded no counterparts to the optical transients. Also, no long-term variability was detected with pre-imaging and follow-up observations using the SkyMapper optical telescope. We place upper limits for minute-timescale fast optical transient rates for a range of depths and timescales. Finally, we demonstrate that optical $g$-band light curve behaviour alone cannot discriminate between confirmed extragalactic fast transients such as prompt GRB flashes and Galactic stellar flares.Comment: Published in MNRA

Got milk? How freedoms evolved from dairying climates

The roots and routes of cultural evolution are still a mystery. Here, we aim to lift a corner of that veil by illuminating the deep origins of encultured freedoms, which evolved through centuries-long processes of learning to pursue and transmit values and practices oriented toward autonomous individual choice. Analyzing a multitude of data sources, we unravel for 108 Old World countries a sequence of cultural evolution reaching from (a) ancient climates suitable for dairy farming to (b) lactose tolerance at the eve of the colonial era to (c) resources that empowered people in the early industrial era to (d) encultured freedoms today. Historically, lactose tolerance peaks under two contrasting conditions: cold winters and cool summers with steady rain versus hot summers and warm winters with extensive dry periods (Study 1). However, only the cold/wet variant of these two conditions links lactose tolerance at the eve of the colonial era to empowering resources in early industrial times, and to encultured freedoms today (Study 2). We interpret these findings as a form of gene-culture coevolution within a novel thermo-hydraulic theory of freedoms

A Detailed Observational Analysis of V1324 Sco, the Most Gamma-Ray Luminous Classical Nova to Date

It has recently been discovered that some, if not all, classical novae emit GeV gamma rays during outburst, but the mechanisms involved in the production of the gamma rays are still not well understood. We present here a comprehensive multi-wavelength dataset---from radio to X-rays---for the most gamma-ray luminous classical nova to-date, V1324 Sco. Using this dataset, we show that V1324 Sco is a canonical dusty Fe-II type nova, with a maximum ejecta velocity of 2600 km s$^{-1}$ and an ejecta mass of few $\times 10^{-5}$ M$_{\odot}$. There is also evidence for complex shock interactions, including a double-peaked radio light curve which shows high brightness temperatures at early times. To explore why V1324~Sco was so gamma-ray luminous, we present a model of the nova ejecta featuring strong internal shocks, and find that higher gamma-ray luminosities result from higher ejecta velocities and/or mass-loss rates. Comparison of V1324~Sco with other gamma-ray detected novae does not show clear signatures of either, and we conclude that a larger sample of similarly well-observed novae is needed to understand the origin and variation of gamma rays in novae.Comment: 26 pages, 13 figure