MOBSTER – III. HD 62658: a magnetic Bp star in an eclipsing binary with a non-magnetic ‘identical twin’

HD 62658 (B9p V) is a little-studied chemically peculiar star. Light curves obtained by the Kilodegree Extremely Little Telescope (KELT) and Transiting Exoplanet Survey Satellite (TESS) show clear eclipses with a period of about 4.75 d, as well as out-of-eclipse brightness modulation with the same 4.75 d period, consistent with synchronized rotational modulation of surface chemical spots. High-resolution ESPaDOnS circular spectropolarimetry shows a clear Zeeman signature in the line profile of the primary; there is no indication of a magnetic field in the secondary. PHOEBE modelling of the light curve and radial velocities indicates that the two components have almost identical masses of about 3 M_⊙. The primary’s longitudinal magnetic field〈B_z〉 varies between about +100 and −250 G, suggesting a surface magnetic dipole strength B_d = 850 G. Bayesian analysis of the Stokes V profiles indicates B_d = 650 G for the primary and B_d < 110 G for the secondary. The primary’s line profiles are highly variable, consistent with the hypothesis that the out-of-eclipse brightness modulation is a consequence of rotational modulation of that star’s chemical spots. We also detect a residual signal in the light curve after removal of the orbital and rotational modulations, which might be pulsational in origin; this could be consistent with the weak line profile variability of the secondary. This system represents an excellent opportunity to examine the consequences of magnetic fields for stellar structure via comparison of two stars that are essentially identical with the exception that one is magnetic. The existence of such a system furthermore suggests that purely environmental explanations for the origin of fossil magnetic fields are incomplete

Integrating biological pathways and genomic profiles with ChiBE 2

Cataloged from PDF version of article.Background: Dynamic visual exploration of detailed pathway information can help researchers digest and interpret complex mechanisms and genomic datasets. Results: ChiBE is a free, open-source software tool for visualizing, querying, and analyzing human biological pathways in BioPAX format. The recently released version 2 can search for neighborhoods, paths between molecules, and common regulators/targets of molecules, on large integrated cellular networks in the Pathway Commons database as well as in local BioPAX models. Resulting networks can be automatically laid out for visualization using a graphically rich, process-centric notation. Profiling data from the cBioPortal for Cancer Genomics and expression data from the Gene Expression Omnibus can be overlaid on these networks. Conclusions: ChiBE's new capabilities are organized around a genomics-oriented workflow and offer a unique comprehensive pathway analysis solution for genomics researchers

Electrical Conductivity of Fermi Liquids. I. Many-body Effect on the Drude Weight

On the basis of the Fermi liquid theory, we investigate the many-body effect on the Drude weight. In a lattice system, the Drude weight $D$ is modified by electron-electron interaction due to Umklapp processes, while it is not renormalized in a Galilean invariant system. This is explained by showing that the effective mass $m'$ for $D\propto n/m'$ is defined through the current, not velocity, of quasiparticle. It is shown that the inequality $D>0$ is required for the stability against the uniform shift of the Fermi surface. The result of perturbation theory applied for the Hubbard model indicates that $D$ as a function of the density $n$ is qualitatively modified around half filling $n\sim 1$ by Umklapp processes.Comment: 20 pages, 2 figures; J. Phys. Soc. Jpn. Vol.67, No.

Lentiviral Vector Delivery of Human Interleukin-7 (hIL-7) to Human Immune System (HIS) Mice Expands T Lymphocyte Populations

Genetically modified mice carrying engrafted human tissues provide useful models to study human cell biology in physiologically relevant contexts. However, there remain several obstacles limiting the compatibility of human cells within their mouse hosts. Among these is inadequate cross-reactvitiy between certain mouse cytokines and human cellular receptors, depriving the graft of important survival and growth signals. To circumvent this problem, we utilized a lentivirus-based delivery system to express physiologically relevant levels of human interleukin-7 (hIL-7) in Rag2-/-γc-/- mice following a single intravenous injection. hIL-7 promoted homeostatic proliferation of both adoptively transferred and endogenously generated T-cells in Rag2-/-γc-/- Human Immune System (HIS) mice. Interestingly, we found that hIL-7 increased T lymphocyte numbers in the spleens of HIV infected HIS mice without affecting viral load. Taken together, our study unveils a versatile approach to deliver human cytokines to HIS mice, to both improve engraftment and determine the impact of cytokines on human diseases

Bosonization and Fermion Liquids in Dimensions Greater Than One

(Revised, with postscript figures appended, corrections and added comments.) We develop and describe new approaches to the problem of interacting Fermions in spatial dimensions greater than one. These approaches are based on generalizations of powerful tools previously applied to problems in one spatial dimension. We begin with a review of one-dimensional interacting Fermions. We then introduce a simplified model in two spatial dimensions to study the role that spin and perfect nesting play in destabilizing Fermion liquids. The complicated functional renormalization group equations of the full problem are made tractable in our model by replacing the continuum of points that make up the closed Fermi line with four Fermi points. Despite this drastic approximation, the model exhibits physically reasonable behavior both at half-filling (where instabilities occur) and away from half-filling (where a Luttinger liquid arises). Next we implement the Bosonization of higher dimensional Fermi surfaces introduced by Luther and advocated most recently by Haldane. Bosonization incorporates the phase space and small-angle scattering .... (7 figures, appended as a postscript file at the end of the TeX file).Comment: 48 text pages, plain TeX, BUP-JBM-

A Common Framework for Integrated and Continuous Biomanufacturing

There is a growing application of integrated and continuous bioprocessing (ICB) for manufacturing recombinant protein therapeutics produced from mammalian cells. At first glance, the newly evolved ICB has created a vast diversity of platforms. A closer inspection reveals convergent evolution: nearly all of the major ICB methods have a common framework that could allow manufacturing across a global ecosystem of manufacturers using simple, yet effective, equipment designs. The framework is capable of supporting the manufacturing of most major biopharmaceutical ICB and legacy processes without major changes in the regulatory license. This article is protected by copyright. All rights reserved

Towards controlling the solid state valence tautomeric interconversion character by solvation

Crystals of [Co<i>(diox)</i>₂­(4-NO₂-py)₂] (<b>1</b>) and [Co<i>(diox)</i>₂­(4-CN-py)₂] (<b>2</b>) where <i>diox</i> are the <i>o</i>-dioxolene 3,5-di-<i>t</i>-butylsemiquinonate (SQ^•–) and/or 3,5-di-<i>t</i>-butylcatecholate (Cat^2–) ions, 4-NO₂-py is 4-nitro-pyridine, 4-CN-py is 4-cyano-pyridine, are among the few known crystals presenting both thermally induced and photoinduced <i>ls</i>-[M⁺³(SQ^•–)­(Cat^2–)] ↔ <i>hs</i>-[M²⁺(SQ^•–)₂] valence tautomeric interconversion (VTI). In <b>2</b>, the thermal-induced VTI is cooperative, characterizing an abrupt conversion, and in <b>1</b> it is noncooperative. In this work, crystals of [Co<i>(diox)</i>₂­(4-NO₂-py)₂]­·benzene (<b>1BZ</b>), [Co<i>(diox)</i>₂­(4-NO₂-py)₂]­·toluene (<b>1TL</b>), [Co<i>(diox)</i>₂­(4-CN-py)₂]­·benzene (<b>2BZ</b>), and [Co<i>(diox)</i>₂­(4-CN-py)₂]­·toluene (<b>2TL</b>) have been prepared and analyzed by single crystal X-ray diffraction in order to investigate how solvation modulates thermally induced VTI. Crystallographic data were also successfully used together with the two-state equilibrium equation to estimate Δ<i>H</i>° and Δ<i>S</i>° VTI thermodynamic parameters. The solvate crystals, like the nonsolvated ones, present essentially reversible thermally induced VTI. The <b>1TL</b> crystal presents the same monoclinic symmetry and the same intermolecular hydrogen-bonded network of <b>1</b>, and both present a noncooperative thermal-induced VTI. The <b>1BZ</b> crystal has triclinic symmetry and presents a cooperative VTI with a thermal hysteresis of ∼30 K. In contrast to <b>2</b>, thermally induced VTI in <b>2BZ</b> and <b>2TL</b> is noncooperative despite the fact that <b>2</b>, <b>2BZ</b>, and <b>2TL</b> crystals exhibit the same monoclinic symmetry and the same intermolecular hydrogen-bonded network. In <b>2BZ</b> and <b>2TL</b> benzene and toluene molecules as well as the <i>t</i>-butyl groups of the <i>o</i>-dioxolene molecules convert gradually from being dynamically disordered at about 300 K to a static disorder state below 150 K. The layer separation distance of interacting [Co<i>(diox)</i>₂­(4-X-py)₂], X = CN and NO₂, molecules in all solvate crystals is ∼15 Å, whereas in <b>2</b>, which presents cooperative VTI, it is ∼12 Å. An order–disorder component might account for the stabilization of the metastable <i>hs</i>-Co²⁺ state in <b>2BZ</b> and in <b>2TL</b>, but no disorder was found in the <b>1TL</b> crystals. Therefore, the lack of cooperativity in the thermally induced VTI in these crystals seems to be due to the large distance between the layers of interacting molecules. Cooperativity in the VTI of <b>1BZ</b> crystal is likely to be related with the unique molecular bond scheme network that connects neighboring active [Co<i>(diox)</i>₂­(4-NO₂-py)₂] molecules through the <i>o</i>-dioxolene oxygen atoms bonded directly to the Co ion

Ground and In-Flight Calibration of the OSIRIS-REx Camera Suite

The OSIRIS-REx Camera Suite (OCAMS) onboard the OSIRIS-REx spacecraft is used to study the shape and surface of the mission’s target, asteroid (101955) Bennu, in support of the selection of a sampling site. We present calibration methods and results for the three OCAMS cameras—MapCam, PolyCam, and SamCam—using data from pre-flight and in-flight calibration campaigns. Pre-flight calibrations established a baseline for a variety of camera properties, including bias and dark behavior, flat fields, stray light, and radiometric calibration. In-flight activities updated these calibrations where possible, allowing us to confidently measure Bennu’s surface. Accurate calibration is critical not only for establishing a global understanding of Bennu, but also for enabling analyses of potential sampling locations and for providing scientific context for the returned sample

Composite quasiparticle formation and the low-energy effective Hamiltonians of the one- and two-dimensional Hubbard Model

We investigate the effect of hole doping on the strong-coupling Hubbard model at half-filling in spatial dimensions $D\ge 1$. We start with an antiferromagnetic mean-field description of the insulating state, and show that doping creates solitons in the antiferromagnetic background. In one dimension, the soliton is topological, spinless, and decoupled from the background antiferromagnetic fluctuations at low energies. In two dimensions and above, the soliton is non-topological, has spin quantum number 1/2, and is strongly coupled to the antiferromagnetic fluctuations. We derive the effective action governing the quasiparticle motion, study the properties of a single carrier, and comment on a possible description at finite concentration.Comment: REVTEX 3.0, 22 pages with 14 figures in the PostScript format compressed using uufile. Submitted to Phys. Rev. B. The complete PostScript file including figures can be obtained via ftp at ftp://serval.berkeley.edu/hubbard.ps . It is also available via www at http://roemer.fys.ku.dk/recent.ht