214,208 research outputs found
A star-forming galaxy at z= 5.78 in the Chandra Deep Field South
No full textWe report the discovery of a luminous z = 5.78 star-forming galaxy in the Chandra Deep Field South. This galaxy was selected as an ‘i-drop’ from the GOODS public survey imaging with the Hubble Space Telescope/Advanced Camera for Surveys (object 3 in the work of Stanway, Bunker & McMahon 2003). The large colour of (i′−z′)AB = 1.6 indicated a spectral break consistent with the Lyman α forest absorption shortward of Lyman α at z≈ 6. The galaxy is very compact (marginally resolved with ACS with a half-light radius of 0.08 arcsec, so rhl 5. Our spectroscopic redshift for this object confirms the validity of the i′-drop technique of Stanway et al. to select star-forming galaxies atz≈ 6
Spectral analysis of the Chandra comet survey
No full textAims.We present results of the analysis of cometary X-ray spectra with an extended version of our charge exchange emission model (Bodewits et al. 2006). We have applied this model to the sample of 8 comets thus far observed with the Chandra X-ray observatory and ACIS spectrometer in the 300-1000 eV range. The surveyed comets are C/1999 S4 (LINEAR), C/1999 T1 (McNaught-Hartley), C/2000 WM1 (LINEAR), 153P/2002 (Ikeya-Zhang), 2P/2003 (Encke), C/2001 Q4 (NEAT), 9P/2005 (Tempel 1) and 73P/2006-B (Schwassmann-Wachmann 3) and the observations include a broad variety of comets, solar wind environments and observational conditions. Methods.The interaction model is based on state selective, velocity dependent charge exchange cross sections and is used to explore how cometary X-ray emission depend on cometary, observational and solar wind characteristics. It is further demonstrated that cometary X-ray spectra mainly reflect the state of the local solar wind. The current sample of Chandra observations was fit using the constrains of the charge exchange model, and relative solar wind abundances were derived from the X-ray spectra. Results.Our analysis showed that spectral differences can be ascribed to different solar wind states, as such identifying comets interacting with (I) fast, cold wind, (II), slow, warm wind and (III) disturbed, fast, hot winds associated with interplanetary coronal mass ejections. We furthermore predict the existence of a fourth spectral class, associated with the cool, fast high latitude wind
Chandra-MARX/marxs: v2.0
No full text<h1>2.0 (02-May-2024)</h1>
<p>In version 2.0 we bring in more instrument models for missions in development. Those models are rapidly changing as the instruments are developed and are not tested to the level of stable code, instead they are meant as examples. There is also new X3D plotting capability and new analysis functionality to look at simulation results.</p>
<h2>What's Changed</h2>
<ul>
<li>make L3 support bars for if no facet is hit by @hamogu in https://github.com/Chandra-MARX/marxs/pull/221</li>
<li>Tolerancing by @hamogu in https://github.com/Chandra-MARX/marxs/pull/222</li>
<li>Ape17 by @hamogu in https://github.com/Chandra-MARX/marxs/pull/223</li>
<li>Try to make GH action pass by @hamogu in https://github.com/Chandra-MARX/marxs/pull/224</li>
<li>Several flixes developed for Arcus combined into one PR by @hamogu in https://github.com/Chandra-MARX/marxs/pull/226</li>
<li>Minor fixes by @hamogu in https://github.com/Chandra-MARX/marxs/pull/227</li>
<li>Upgrade to GitHub-native Dependabot by @dependabot-preview in https://github.com/Chandra-MARX/marxs/pull/228</li>
<li>Prevent problems with probability < 0 or > 1 by @hamogu in https://github.com/Chandra-MARX/marxs/pull/229</li>
<li>Followup with files forgotten in #229 by @hamogu in https://github.com/Chandra-MARX/marxs/pull/230</li>
<li>Looks like a type in an untested try/except block by @hamogu in https://github.com/Chandra-MARX/marxs/pull/231</li>
<li>Improve chandra by @hamogu in https://github.com/Chandra-MARX/marxs/pull/232</li>
<li>add clip to prevent numerical problems in arccos by @hamogu in https://github.com/Chandra-MARX/marxs/pull/234</li>
<li>Modify analyser to account for chip gap by @hamogu in https://github.com/Chandra-MARX/marxs/pull/235</li>
<li>Infra_update by @hamogu in https://github.com/Chandra-MARX/marxs/pull/236</li>
<li>InterpolateEfficiencyTable now takes table, not filename as input by @hamogu in https://github.com/Chandra-MARX/marxs/pull/237</li>
<li>Add X3d visualization backend by @hamogu in https://github.com/Chandra-MARX/marxs/pull/238</li>
<li>Update GH actions to run on current nodes by @hamogu in https://github.com/Chandra-MARX/marxs/pull/241</li>
<li>RDT: deprecate system packages by @hamogu in https://github.com/Chandra-MARX/marxs/pull/242</li>
<li>Integrate missions into marxs by @hamogu in https://github.com/Chandra-MARX/marxs/pull/240</li>
<li>x3d visualization: transparancy/opacity by @hamogu in https://github.com/Chandra-MARX/marxs/pull/243</li>
<li>Improve X3D output by @hamogu in https://github.com/Chandra-MARX/marxs/pull/244</li>
<li>Add functions to general channels in double-tilted Rowland design by @hamogu in https://github.com/Chandra-MARX/marxs/pull/245</li>
<li>Change the defaults double rowland torus to standard xyz axes. by @hamogu in https://github.com/Chandra-MARX/marxs/pull/246</li>
<li>Increase consistency in where the Rowland tori are oriented by @hamogu in https://github.com/Chandra-MARX/marxs/pull/247</li>
<li>Add option for reflectivity and optical axis offset from geometrical center of PerfectLens by @hamogu in https://github.com/Chandra-MARX/marxs/pull/248</li>
<li>X3dplot by @hamogu in https://github.com/Chandra-MARX/marxs/pull/249</li>
<li>Fix design_tilted_torus by @hamogu in https://github.com/Chandra-MARX/marxs/pull/250</li>
<li>Add method to create archive files for publishing of X3D visualization. by @hamogu in https://github.com/Chandra-MARX/marxs/pull/251</li>
<li><code>CCDRedistNormal</code> now inherits from an optical element . by @hamogu in https://github.com/Chandra-MARX/marxs/pull/252</li>
</ul>
<h2>New Contributors</h2>
<ul>
<li>@dependabot-preview made their first contribution in https://github.com/Chandra-MARX/marxs/pull/228</li>
</ul>
<p><strong>Full Changelog</strong>: https://github.com/Chandra-MARX/marxs/compare/v1.2...v2.0</p>
Negatively supercharging cellulases render them lignin-resistant
No full textNon-specific adsorption of cellulases to lignin hinders enzymatic deconstruction of lignocellulosic biomass. Here we tested the hypothesis that negatively supercharging cellulases could reduce lignin inhibition. Computational design was used to negatively supercharge the surfaces of Ruminoclostridium thermocellum family 5 CelE and a CelE-family 3a carbohydrate binding module fusion. Resulting designs maintained the same expression yield, thermal stability, and nearly identical activity on soluble substrate as the wild-type proteins. Four designs showed complete lack of inhibition by lignin but with lower cellulose conversion compared to original enzymes. Increasing salt concentrations could partially rescue the activity of supercharged enzymes, supporting a mechanism of electrostatic repulsion between designs and cellulose. Results showcase a protein engineering strategy to construct highly active cellulases that are resistant to lignin-mediated inactivation, although further work is needed to understand the relationship between negative protein surface potential and activity on insoluble polysaccharides.Peer reviewe
Trigonometric approximation by Nörlund type means in -norm
No full textsummary:We show that the same degree of approximation as in the theorems proved by L. Leindler [Trigonometric approximation in -norm, J. Math. Anal. Appl. 302 (2005), 129--136] and P. Chandra [Trigonometric approximation of functions in -norm, J. Math. Anal. Appl. 275 (2002), 13--26] is valid for a more general class of lower triangular matrices. We also prove that these theorems are true under weakened assumptions
Replication of gridded emission Data for: Methane emissions decreased in fossil fuel exploitation and sustainably increased in microbial source sectors during 1990–2020
No full text<p>CH<sub>4</sub> emission scenarios, based on bottom-up emission estimates (Chandra et al., CEE, 2024; Fig 2) for simulating the long-term trends and latitudinal gradients of CH<sub>4</sub> and <em>δ</em><sup>13</sup>C-CH<sub>4</sub>. The details can be found at </p>
<p>Chandra, N., Patra, P.K., Fujita, R. <em>et al.</em> Methane emissions decreased in fossil fuel exploitation and sustainably increased in microbial source sectors during 1990–2020. <em>Commun Earth Environ</em> <strong>5</strong>, 147 (2024). https://doi.org/10.1038/s43247-024-01286-x</p>
MIROC4-ACTM CO2 Inversion flux (2001-2022)
No full text<p>This dataset is prepared for GCP CO2-2023 assessment. </p>
<p>Inversion Details are in:</p>
<div>
<div>Chandra, N., Patra, P. K., Niwa, Y., Ito, A., Iida, Y., Goto, D., Morimoto, S., Kondo, M., Takigawa, M., Hajima, T., and Watanabe, M.: Estimated regional CO<sub>2</sub> flux and uncertainty based on an ensemble of atmospheric CO<sub>2</sub> inversions, Atmos. Chem. Phys., 22, 9215–9243, https://doi.org/10.5194/acp-22-9215-2022, 2022</div>
<div> </div>
<div>MIROC4-ACTM Details:</div>
<div><span>Patra, P. K., Takigawa, M., Watanabe, S., Chandra, N., Ishijima, K., and Yamashita, Y.: Improved Chemical Tracer Simulation by MIROC4.0-based Atmospheric Chemistry-Transport Model (MIROC4-ACTM), SOLA, 14, 91–96, <a href="https://doi.org/10.2151/sola.2018-016">https://doi.org/10.2151/sola.2018-016</a>, 2018. </span></div>
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First observation of Jupiter by XMM-Newton
No full textWe present the first X-ray observation of Jupiter by XMM-Newton. Images taken with the EPIC cameras show prominent emission, essentially all confined to the 0.2-2.0 keV band, from the planet's auroral spots; their spectra can be modelled with a combination of unresolved emission lines of highly ionised oxygen (OVII and OVIII), and a pseudo-continuum which may also be due to the superposition of many weak lines. A 2.8sigma enhancement in the RGS spectrum at 21-22 Angstrom (similar to0.57 keV) is consistent with an OVII identification. Our spectral analysis supports the hypothesis that Jupiter's auroral emissions originate from the capture and acceleration of solar wind ions in the planet's magnetosphere, followed by X-ray production by charge exchange. The X-ray flux of the North spot is modulated at Jupiter's rotation period. We do not detect evidence for the similar to45 min X-ray oscillations observed by Chandra more than two years earlier. Emission from the equatorial regions of the planet's disk is also observed. Its spectrum is consistent with that of scattered solar X-rays
A remark on rational Cherednik algebras and differential operators on the cyclic quiver
No full textWe show that the spherical subalgebra Uk,c of the rational Cherednik algebra associated to Sn 2 Cl, the wreath product of the symmetric group and the cyclic group of order l, is isomorphic to a quotient of the ring of invariant differential operators on a space of representations of the cyclic quiver of size l. This confirms a version of [5, Conjecture 11.22] in the case of cyclic groups. The proof is a straightforward application of work of Oblomkov [12] on the deformed Harish–Chandra homomorphism, and of Crawley–Boevey, [3] and [4], and Gan and Ginzburg [7] on preprojective algebras
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