Transcriptional silencing may not necessarily depend on the continuous residence of a sequence‐specific repressor at a control element and may act via a “hit and run” mechanism. Due to limitations in assays that detect transcription factor (TF) binding, such as chromatin immunoprecipitation followed by high‐throughput sequencing (ChIP‐seq), this phenomenon may be challenging to detect and therefore its prevalence may be underappreciated. To explore this possibility, erythroid gene promoters that are regulated directly by GATA1 in an inducible system are analyzed. It (...) is found that many regulated genes are bound immediately after induction of GATA1 but the residency of GATA1 decreases over time, particularly at repressed genes. Furthermore, it is shown that the repressive mark H3K27me3 is seldom associated with bound repressors, whereas, in contrast, the active (H3K4me3) histone mark is overwhelmingly associated with TF binding. It is hypothesized that during cellular differentiation and development, certain genes are silenced by repressive TFs that subsequently vacate the region. Catching such repressor TFs in the act of silencing via assays such as ChIP‐seq is thus a temporally challenging prospect. The use of inducible systems, epitope tags, and alternative techniques may provide opportunities for detecting elusive “hit and run” transcriptional silencing. Also see the video abstract here https://youtu.be/vgrsoP_HF3g. (shrink)

© 2017. The American Astronomical Society. All rights reserved.We present new observations of the low-mass companion to HD 984 taken with the Gemini Planet Imager as a part of the GPI Exoplanet Survey campaign. Images of HD 984 B were obtained in the J and H bands. Combined with archival epochs from 2012 and 2014, we fit the first orbit to the companion to find an 18 au orbit with a 68% confidence interval between 14 and 28 au, an eccentricity (...) of 0.18 with a 68% confidence interval between 0.05 and 0.47, and an inclination of 119°with a 68% confidence interval between 114°and 125°. To address the considerable spectral covariance in both spectra, we present a method of splitting the spectra into low and high frequencies to analyze the spectral structure at different spatial frequencies with the proper spectral noise correlation. Using the split spectra, we compare them to known spectral types using field brown dwarf and low-mass star spectra and find a best-fit match of a field gravity M6.5 ±1.5 spectral type with a corresponding temperature of K. Photometry of the companion yields a luminosity of log=2.88 ± 0.07 dex with DUSTY models. Mass estimates, again from DUSTY models, find an age-dependent mass of 34 ±1 to 95 ±4 M Jup. These results are consistent with previous measurements of the object. (shrink)

Study of the European Enlightenment could do with a fillip. Perhaps the best tonic we have is combining the close reading of significant works with the study of print history and reader reception....

Study of the European Enlightenment could do with a fillip. Perhaps the best tonic we have is combining the close reading of significant works with the study of print history and reader reception....

Since the publication of Edmund Gettier's challenge to the traditional epistemological doctrine of knowledge as justified true belief, Roberts and Wood claim that epistemologists lapsed into despondency and are currently open to novel approaches. One such approach is virtue epistemology, which can be divided into virtues as proper functions or epistemic character traits. The authors propose a notion of regulative epistemology, as opposed to a strict analytic epistemology, based on intellectual virtues that function not as rules or even as skills (...) but as habits of the heart. To that end, they divide the task of clarifying and expounding their notion in the book's two parts.In the first part, Roberts and Wood examine various components that constitute their notion of regulative epistemology. The first are the epistemic goods or goals that drive the epistemic process. What is needed, claim Roberts and Wood, is an enriched notion of these goods rather than the restricted notion of justified true belief. Epistemic agents are more than calculating devices in that …. (shrink)

Research involving recently deceased humans that are physiologically maintained following declaration of death by neurologic criteria—or ‘research involving the recently deceased’—can fill a translational research gap while reducing harm to animals and living human subjects. It also creates new challenges for honouring the donor’s legacy, respecting the rights of donor loved ones, resource allocation and public health. As this research model gains traction, new empirical ethics questions must be answered to preserve public trust in all forms of tissue donation and (...) in the practice of medicine while respecting the legacy of the deceased and the rights of donor loved ones. This article suggests several topics for immediate investigation to understand the attitudes and experiences of researchers, clinical collaborators, donor loved ones and the public to ensure research involving the recently deceased advances ethically. (shrink)

Eric Olsen argues from the fact that we once existed as fetal individuals to the conclusion that the Standard View of personal identity is mistaken. I shall establish that a similar argument focusing upon dead people opposes Olson’s favored Biological View of personal identity.

The paper „F. W. Bessel and Russian science by K. K. Lavrinovich published in NTM-Schriftenreihe contains several errors coming mainly from re-translations of German names and texts from Russian into German. The correct spelling of names and original texts are given here. Beside this, some additional information from sources not mentioned by the author is presented, and the kind of relationship between Bessel and W. Struve is discussed on the basis of their correspondence.

Until fairly recently a common way of doing history of science was to pick up an important strand of contemporary scientific thought and to trace its origin back to the philosophical tangle of the scientific revolution. This approach conveniently by-passed the breakdowns of once useful and pervasive theories, and neglected the long intellectual journeys along devious routes. History of science read like a success story; the pioneers who failed were neither dismissed nor excused; they were simply ignored. The historian knew (...) what he was hunting for and he was careful to limit his search to areas where his quarry was sure to be found. This method, which has been dubbed the precursor-view, stands in contrast—albeit, not in opposition—to the contextual method, which aims at a better understanding of the actual thought-processes of the early scientists. On this second view, history of science must not only account for present theories in the light of past developments, it must also assess old theories in terms of the scientist's conceptual framework, and judge them against the background of the world picture of his age. This may lead the historian down the blind alleys of the past, chasing spurious attempts at explaining the nature of physical reality, but it can clear the ground for a less anachronistic interpretation of the emergence of modern science and the actual process of discovery. History of science acts as a winnowing fork, but we cannot suppose that the discoverer himself always separated the wheat from the chaff, and we must be ever wary of equating the dream with the task. (shrink)

Two recent papers by Michael Burke bearing upon the persistence of people and commonplace things illustrate the fact that the quest for synchronic ontological economy is likely to encourage a disturbing diachronic proliferation of entities. This discussion argues that Burke's promise of ontological economy is seriously compromised by the fact that his proposed metaphysic does violence to standard intuitions concerning the persistence of people and commonplace things. In effect, Burke would have us achieve synchronic economy (rejection of coincident entities) by (...) postulating strongly counterintuitive transtemporal claims of numerical diversity. The argument is made that the price of Burkean economy is too high. (shrink)