Constraints on the Equation-of-State of neutron stars from nearby neutron star observations

We try to constrain the Equation-of-State (EoS) of supra-nuclear-density matter in neutron stars (NSs) by observations of nearby NSs. There are seven thermally emitting NSs known from X-ray and optical observations, the so-called Magnificent Seven (M7), which are young (up to few Myrs), nearby (within a few hundred pc), and radio-quiet with blackbody-like X-ray spectra, so that we can observe their surfaces. As bright X-ray sources, we can determine their rotational (pulse) period and their period derivative from X-ray timing. From XMM and/or Chandra X-ray spectra, we can determine their temperature. With precise astrometric observations using the Hubble Space Telescope, we can determine their parallax (i.e. distance) and optical flux. From flux, distance, and temperature, one can derive the emitting area - with assumptions about the atmosphere and/or temperature distribution on the surface. This was recently done by us for the two brightest M7 NSs RXJ1856 and RXJ0720. Then, from identifying absorption lines in X-ray spectra, one can also try to determine gravitational redshift. Also, from rotational phase-resolved spectroscopy, we have for the first time determined the compactness (mass/radius) of the M7 NS RBS1223. If also applied to RXJ1856, radius (from luminosity and temperature) and compactness (from X-ray data) will yield the mass and radius - for the first time for an isolated single neutron star. We will present our observations and recent results.Comment: refereed NPA5 conference proceedings, in pres

On identifying the neutron star that was born in the supernova that placed 60Fe onto the Earth

Recently, 60Fe was found in the Earth crust formed in a nearby recent supernova (SN). If the distance to the SN and mass of the progenitor of that SN was known, then one could constrain SN models. Knowing the positions, proper motions, and distances of dozens of young nearby neutron stars, we can determine their past flight paths and possible kinematic origin. Once the birth place of a neutron star in a SN is found, we would have determined the distance of the SN and the mass of the SN progenitor star.Comment: refereed NPA5 conference proceedings, in pres

Transition from non-motile behaviour to directed migration during early PGC development in zebrafish

International audienceThe migration of zebrafish primordial germ cells (PGCs) is directed by SDF-1a and serves as a model for long-range chemokine-guided cell migration. Whereas the development and migration of zebrafish PGCs have been studied in great detail starting at mid-gastrulation stages when the cells exhibit guided active migration [7-8 hours post fertilization (hpf)], earlier stages have not yet been examined. Here we show that the PGCs acquire competence to respond to the chemokine following discrete maturation steps. Using the promoter of the novel gene askopos and RNA elements of nanos1 to drive GFP expression in PGCs, we found that immediately after their specification (about 3 hpf) PGCs exhibit simple cell shape. This stage is followed by a phase at which the cells assume complex morphology yet they neither change their position nor do they respond to SDF-1a. During the third phase, a transition into a ;migratory stage' occurs as PGCs become responsive to directional cues provided by somatic cells secreting the chemokine SDF-1a. This transition depends on zygotic transcription and on the function of the RNA-binding protein Dead end and is correlated with down regulation of the cell adhesion molecule E-cadherin. These distinctive morphological and molecular alterations could represent a general occurrence in similar processes critical for development and disease

Favouritism: exploring the 'uncontrolled' spaces of the leadership experience

In this paper, we argue that a focus on favouritism magnifies a central ethical ambiguity in leadership, both conceptually and in practice. The social process of favouritism can even go unnoticed, or misrecognised if it does not manifest in a form in which it can be either included or excluded from what is (collectively interpreted as) leadership. The leadership literature presents a tension between what is an embodied and relational account of the ethical, on the one hand, and a more dispassionate organisational ‘justice’ emphasis, on the other hand. We conducted 23 semi-structured interviews in eight consultancy companies, four multinationals and four internationals. There were ethical issues at play in the way interviewees thought about favouritism in leadership episodes. This emerged in the fact that they were concerned with visibility and conduct before engaging in favouritism. Our findings illustrate a bricolage of ethical justifications for favouritism, namely utilitarian, justice, and relational. Such findings suggest the ethical ambiguity that lies at the heart of leadership as a concept and a practice

The effects of customer equity drivers on loyalty across services industries and firms

Customer equity drivers (CEDs)—value equity, brand equity, and relationship equity—positively affect loyalty intentions, but this effect varies across industries and firms. We empirically examine potential industry and firm characteristics that explain why the CEDs–loyalty link varies across services industries and firms in the Netherlands. The results show that (1) some previously assumed industry and firm characteristics have moderating effects while others do not and (2) firm-level advertising expenditures constitute the most crucial moderator because they influence all three loyalty strategies (significant for value equity and brand equity; marginally significant for relationship equity), while three industry contexts (i.e., innovative markets, visibility to others, and complexity of purchase decisions) each influence two of the three loyalty strategies. Our results clearly show that specific industry and firm characteristics affect the effectiveness of specific loyalty strategies

Epigenetic modulators as therapeutic targets in prostate cancer

Prostate cancer is one of the most common non-cutaneous malignancies among men worldwide. Epigenetic aberrations, including changes in DNA methylation patterns and/or histone modifications, are key drivers of prostate carcinogenesis. These epigenetic defects might be due to deregulated function and/or expression of the epigenetic machinery, affecting the expression of several important genes. Remarkably, epigenetic modifications are reversible and numerous compounds that target the epigenetic enzymes and regulatory proteins were reported to be effective in cancer growth control. In fact, some of these drugs are already being tested in clinical trials. This review discusses the most important epigenetic alterations in prostate cancer, highlighting the role of epigenetic modulating compounds in pre-clinical and clinical trials as potential therapeutic agents for prostate cancer management.info:eu-repo/semantics/publishedVersio

Magma plumbing systems: a geophysical perspective

Over the last few decades, significant advances in using geophysical techniques to image the structure of magma plumbing systems have enabled the identification of zones of melt accumulation, crystal mush development, and magma migration. Combining advanced geophysical observations with petrological and geochemical data has arguably revolutionised our understanding of, and afforded exciting new insights into, the development of entire magma plumbing systems. However, divisions between the scales and physical settings over which these geophysical, petrological, and geochemical methods are applied still remain. To characterise some of these differences and promote the benefits of further integration between these methodologies, we provide a review of geophysical techniques and discuss how they can be utilised to provide a structural context for and place physical limits on the chemical evolution of magma plumbing systems. For example, we examine how Interferometric Synthetic Aperture Radar (InSAR), coupled with Global Positioning System (GPS) and Global Navigation Satellite System (GNSS) data, and seismicity may be used to track magma migration in near real-time. We also discuss how seismic imaging, gravimetry and electromagnetic data can identify contemporary melt zones, magma reservoirs and/or crystal mushes. These techniques complement seismic reflection data and rock magnetic analyses that delimit the structure and emplacement of ancient magma plumbing systems. For each of these techniques, with the addition of full-waveform inversion (FWI), the use of Unmanned Aerial Vehicles (UAVs) and the integration of geophysics with numerical modelling, we discuss potential future directions. We show that approaching problems concerning magma plumbing systems from an integrated petrological, geochemical, and geophysical perspective will undoubtedly yield important scientific advances, providing exciting future opportunities for the volcanological community

Referenzmethoden zur quantitativen Bestimmung von Peptid- und Proteohormonen mit Mikro-HPLC

14 figs.SIGLETIB Hannover: FR 3481+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman