11 research outputs found
THE BANANA PROJECT. VI. Close double stars are well aligned with noticeable exceptions; results from an ensemble study using apsidal motion and Rossiter-McLaughlin measurements
No full textHere we present an ensemble study of spin-orbit alignment in 51 close double
star systems. We determine spin-orbit angles, obliquities, in 39 of these
systems making use of recently improved apsidal motion rate measurements and
apsidal motion constants. In the remaining 12 systems researchers have
constrained spin-orbit alignment by different combinations of measurements of
apsidal motion rates, projected obliquities and stellar inclinations. Of the 51
systems 48 are consistent with alignment albeit with some measurements having
large uncertainties. A Fisher distribution with mean zero and a concentration
factor represents this ensemble well. Indeed employing a
bootstrapping resampling technique we find our data on these 48 systems is
consistent with perfect alignment. We also confirm significant misalignment in
two systems which travel on eccentric orbits and where misalignments have been
reported on before, namely DI Her and AS Cam. The third misaligned system CV
Vel orbits on a circular orbit. So while there are some glaring exceptions, the
majority of close double star systems for which data are available appear to be
well aligned.Comment: 13 pages, 5 figures, 1 tabl
Spectroscopic Follow-up of Gaia Exoplanet Candidates: Impostor Binary Stars Invade the Gaia DR3 Astrometric Exoplanet Candidates
No full textIn this paper, we report on the follow-up of six potential exoplanets detected with Gaia astrometry and provide an overview of what is currently known about the nature of the entire Gaia astrometric exoplanet candidate sample, 72 systems in total. We discuss the primary false-positive scenario for astrometric planet detections: binary systems with alike components that produce small photocenter motions, mimicking exoplanets. These false positives can be identified as double-lined binaries (SB2) through analysis of high-resolution spectra. Doing so we find that three systems, Gaia DR3 1916454200349735680, Gaia DR3 2052469973468984192, and Gaia DR3 5122670101678217728, are indeed near-equal-mass double-star systems rather than exoplanetary systems. The spectra of the other two analyzed systems, HD 40503 and HIP 66074, are consistent with the exoplanet scenario in that no second set of lines can be found in the time series of publicly available high-resolution spectra. However, their Gaia astrometric solutions imply radial-velocity semiamplitudes ∼3 (HD 40503) and ∼15 (HIP 66074) larger than what was observed with ground-based spectrographs. The Gaia astrometry orbital solutions and ground-based radial-velocity measurements exhibit inconsistencies in six out of a total of 12 exoplanet candidate systems where such data are available, primarily due to substantial differences between observed ground-based radial-velocity semiamplitudes and those implied by the Gaia orbits. We investigated various hypotheses as to why this might be the case, and although we found no clear perpetrator, we note that a mismatch in orbital inclination offers the most straightforward explanation
The BANANA Project. VII. High Eccentricity Predicts Spin-Orbit Misalignment in Binaries
No full textThe degree of spin-orbit alignment in a population of binary stars can be determined from measurements of their orbital inclinations and rotational broadening of their spectral lines. Alignment in a face-on binary guarantees low rotational broadening, while alignment in an edge-on binary maximizes the rotational broadening. In contrast, if spin-orbit angles () are random, rotational broadening should not depend on orbital inclination. Using this technique, we investigated a sample of 2{,}727 astrometric binaries from Gaia DR3 with F-type primaries and orbital periods between 50 and 1000 days (separations 0.3--2.7~au). We found that is strongly associated with , the orbital eccentricity. When , it rises to \,degrees. These results suggest that some binaries are affected by processes during their formation or evolution that excite both orbital eccentricity and inclination
Mechanisms of calcineurin inhibitor nephrotoxicity in chronic allograft injury
No full textThe first successful transplantation of a human kidney was performed more than 50 years ago by Murray and colleagues in 1954 between identical twins. The success of this transplantation was due to the fact that no significant rejection occurs between genetically identical twins and therefore immunosuppression was not necessary in this particular case (Merrill et al., 1956).
However, solid-organ transplantation could not be considered truly successful until the 1970’s after significant technical and pharmacological advances. In particular, the discovery and development of the calcineurin inhibitors (CNIs) has made allograft transplantation routinely successful with greatly reduced risk of acute rejection. In the absence of pharmacological agents to address the primary pathological mechanisms involved, renal transplantation has now been the standard management of end stage renal failure for the past four decades (Wolfe
et al., 1999). Short-term renal allograft and allograft recipient survival rates have increased significantly during the last decade largely due to improved patient monitoring. However, allograft half-life beyond 1 year post-transplant remains largely unchanged. While rates of early allograft failure have significantly reduced, late renal allograft dysfunction remains a significant problem in the transplant population (de Fijter). Chronic allograft injury (CAI) is the most prevalent cause of allograft dysfunction in the first decade after transplantation. The term CAI is used to describe deterioration of renal allograft function and structure due to
immunological processes (i.e. chronic rejection) and/or a range of simultaneous nonimmunological factors such as CNI-induced nephrotoxicity, hypertension and infection. This chapter will outline the pathophysiology and etiology of CAI and the role that CNI nephrotoxicity plays in this disease process. It will also review experimental studies that have identified important molecular mechanisms involved and discuss strategies utilised to minimise the development and progression of CAI.Science Foundation IrelandHigher Education AuthorityIrish Research Council for Science, Engineering and TechnologyEuropean Research CouncilHealth Research BoardEnterprise Irelandti, ke, ab, de - TS 29.03.1
Investigations of FIBCD1: Immunohistochemical localization and immunomodulatory role upon helminth antigen stimulation in colon epithelium
No full textIntroduction: Fibrinogen C domain-containing 1 (FIBCD1) is a homotetrameric type II transmembrane protein, expressed at epithelial surfaces. FIBCD1 has a wide ligand spectrum, including chitin found in various pathogens such as helminths and fungi. Current under-standing points towards a role as a pattern recognition receptor in the innate immune response. Aim: In the present study, we investigate the localization of FIBCD1 in 49 different healthy human tissues by immunohistochemistry. Further, we investigate the in vitro effects of excretory-secretory (ES) antigens from pig whipworm (Trichuris suis) on FIBCD1-transfected colon epithelial cells, and identify protein fractions in the ES-antigen that binds to FIBCD1. Results: Immunohistochemical staining shows that FIBCD1 is present at mucosal surfaces throughout the human body, with high intensity in the airways and gastrointestinal and urogenital tract. Transfection of the human colon epithelial cell line HCT116 with FIBCD1 did not result in any major genotypic differences upon stimulation with ES antigens, as determined by quantitative PCR of various pro- and anti-inflammatory genes. FIBCD1 recognizes and binds to whipworm eggshell and ES antigens. Analysis of the T. suis ES-antigen by size chromatography reveals predominant sizes of proteins ranging from 10 kDa to 200 kDa. Conclusion: FIBCD1 is present at mucosal surfaces throughout the human body, which may underline its function as a pattern recognition receptor in the innate immune system. FIBCD1 binds to ES antigens. Stimula-tion with ES antigens does not appear to be influenced by FIBCD1 transfection in vitro. FIBCD1 may play a role in whipworm infections in vivo
A puffy polar planet
No full textTOI-640 b is a hot, puffy Jupiter with a mass of 0.57 ± 0.02 MJ and radius of 1.72 ± 0.05 RJ, orbiting a slightly evolved F-type star with a separation of 6.33−0.06+0.07 R⋆. Through spectroscopic in-transit observations made with the HARPS spectrograph, we measured the Rossiter-McLaughlin effect, analysing both in-transit radial velocities and the distortion of the stellar spectral lines. From these observations, we find the host star to have a projected obliquity of λ = 184 ± 3°. From the TESS light curve, we measured the stellar rotation period, allowing us to determine the stellar inclination, i⋆ = 23−2+3°, meaning we are viewing the star pole-on. Combining this with the orbital inclination allowed us to calculate the host star obliquity, ψ = 104 ± 2°. TOI-640 b joins a group of planets orbiting over stellar poles within the range 80°–125°. The origin of this orbital configuration is not well understood
Astrometry and Precise Radial Velocities Yield a Complete Orbital Solution for the Nearby Eccentric Brown Dwarf LHS 1610 b
No full textThe LHS 1610 system consists of a nearby (d = 9.7 pc) M5 dwarf hosting a candidate brown dwarf companion in a 10.6 days, eccentric (e ∼ 0.37) orbit. We confirm this brown dwarf designation and estimate its mass ( 49.5 − 3.5 + 4.3 M Jup) and inclination (114.5° − 10.0 + 7.4 ) by combining discovery radial velocities (RVs) from the Tillinghast Reflector Echelle Spectrograph and new RVs from the Habitable-zone Planet Finder with the available Gaia astrometric two-body solution. We highlight a discrepancy between the measurement of the eccentricity from the Gaia two-body solution (e = 0.52 ± 0.03) and the RV-only solution (e = 0.3702 ± 0.0003). We discuss possible reasons for this discrepancy, which can be further probed when the Gaia astrometric time series become available as part of Gaia Data Release 4. As a nearby mid-M star hosting a massive short-period companion with a well-characterized orbit, LHS 1610 b is a promising target to look for evidence of sub-Alfvénic interactions and/or auroral emission at optical and radio wavelengths. LHS 1610 has a flare rate (0.28 ± 0.07 flares per day) on the higher end for its rotation period (84 ± 8 days), similar to other mid-M dwarf systems such as Proxima Cen and YZ Ceti that have recent radio detections compatible with star-planet interactions. While available Transiting Exoplanet Survey Satellite photometry is insufficient to determine an orbital phase dependence of the flares, our complete orbital characterization of this system makes it attractive to probe star-companion interactions with additional photometric and radio observations.</p
Bureaucratic culture and new public management:: a case study of Indira Mahila Yojana in Uttar Pradesh
No full textDuring the 1990s there has been a notable shift in governance debates from what has been termed the 'Washington' to a post-Washington Consensus. Put simply, this shift has involved a move away from the old agenda of state 'versus' market to a new discourse based on the notion of state 'and’ market. A parallel shift has occurred within public administration, from a focus based on reducing the role of the state to a reconsideration of the way in which the state performs its roles. The Indian state has initiated administrative reforms influenced by new public management (NPM) following the adoption of a new economic policy in 1991. The case of northern Indian state of Uttar Pradesh, is particularly significant as administrative reforms their have been developed in association with the World Bank. Through the case study of the Indira Mahila Yojana programme (for women's empowerment), I consider how government officials at the various administrative levels, have engaged with the processes of change associated with new public management. Despite popular criticism of the bureaucracy in India, this study suggests that the adoption of specific elements of NPM in specific institutional environments can empower government officials, and help facilitate development. The case study of the Indira Mahila Yojana scheme demonstrates both the importance of supporting institutions and the potential value of bureaucratic reform for provoking positive change and development
Gaia-4b and 5b: Radial Velocity Confirmation of Gaia Astrometric Orbital Solutions Reveal a Massive Planet and a Brown Dwarf Orbiting Low-mass Stars
No full textGaia astrometry of nearby stars is precise enough to detect the tiny displacements induced by substellar companions, but radial velocity (RV) data are needed for definitive confirmation. Here we present RV follow-up observations of 28 M and K stars with candidate astrometric substellar companions, which led to the confirmation of two systems, Gaia-4b and Gaia-5b, identification of five systems that are single lined but require additional data to confirm as substellar companions, and the refutation of 21 systems as stellar binaries. Gaia-4b is a massive planet (M = 11.8 +/- 0.7 MJ) in a P = 571.3 +/- 1.4 day orbit with a projected semimajor axis a0 = 0.312 +/- 0.040 mas orbiting a 0.644 +/- 0.02M circle dot star. Gaia-5b is a brown dwarf (M = 20.9 +/- 0.5MJ) in a P = 358.62 +/- 0.20 days eccentric e = 0.6423 +/- 0.0026 orbit with a projected angular semimajor axis of a0 = 0.947 +/- 0.038 mas around a 0.34 +/- 0.03M circle dot star. Gaia-4b is one of the first exoplanets discovered via the astrometric technique, and is one of the most massive planets known to orbit a low-mass star
Educating for the future : a critical discourse analysis of the field of intercultural business communication
No full textThe investigation analyzes critically the discursive and generic make-up, the conceptual base and educational goals of a new interdisciplinary academic field of enquiry called Intercultural Business Communication as it is pursued in the context of the Germany higher education system. Its purpose is twofold: Firstly, it attempts to bring to light and debate the actual validity claims made by these authors in respect to socio-economic changes and the educational promise of intercultural understanding through intercultural training. Secondly, it shows how aspects of context (e.g. interdisciplinary relations, disciplinary intricacies, hegemonic discourses, changes in the higher educational system and its relation to other social spheres) can impact upon the discourse and genre of social science in general and this particular field in particular. By drawing upon Critical Discourse Analysis as a theoretical stance and a methodological path, a corpus of 24 academic articles published in this area is analyzed in relation to the recontextualization of socio-economic changes (presences and absences of social actors, processes and evaluation), the legitimation of educational goals through reference to these changes, the conceptualization of key terms (like culture, the other etc.), the implications of these theoretical decisions for the possibility of increased, mutual understanding and the form of academic writing (argumentation, debate, genre change). While the thesis aims to identify specific discursive and generic patterns, open them to contestation, and to explain their presence in these texts, it is also strongly normative and discusses questions related to the changing understanding of the nature, form and function of academic knowledge production in society
