We use 3D hydrodynamic simulations of the long-term evolution of neutron star merger ejecta to predict the light curves of electromagnetic transients that are powered by the decay of freshly produced r-process nuclei. For the dynamic ejecta that are launched by tidal and hydrodynamic interaction, we adopt grey opacities of 10 cm 2 /g, as suggested by recent studies. For our reference case of a 1.3 -1.4 M merger, we find a broad IR peak 2-4 d after the merger. The peak luminosity is ≈ 2 × 10 40 erg/s for an average orientation, but increased by up to a factor of 4 for more favourable binary parameters and viewing angles. These signals are rather weak and hardly detectable within the large error box (∼ 100 deg 2 ) of a gravitational wave trigger. A second electromagnetic transient results from neutrino-driven winds. These winds produce 'weak' r-process material with 50 < A < 130 and abundance patterns that vary substantially between different merger cases. For an adopted opacity of 1 cm 2 /g, the resulting transients peak in the UV/optical about 6 h after the merger with a luminosity of ≈ 10 41 erg/s (for a wind of 0.01 M ) These signals are marginally detectable in deep follow-up searches (e.g. using Hypersuprime camera on Subaru). A subsequent detection of the weaker but longer lasting IR signal would allow an identification of the merger event. We briefly discuss the implications of our results to the recent detection of an nIR transient accompanying GRB 130603B.
Abstract. An EPR experiment is studied where each particle undergoes a few weak measurements along some pre-set spin orientations, whose outcomes are individually recorded. Then the particle undergoes a strong measurement along a spin orientation freely chosen at the last moment. Bell-inequality violation is expected between the two final strong measurements within each EPR pair. At the same time, agreement is expected between these measurements and the earlier weak ones within the pair. A contradiction thereby ensues: i) Bell's theorem forbids spin values to exist prior to the choice of the spin-orientation to be measured; ii) A weak measurement cannot determine the outcome of a successive strong one; and iii) Indeed no disentanglement is inflicted by the weak measurements; yet iv) The weak measurements' outcomes agree with those of the strong ones. The most reasonable resolution seems to be that of the Two-StateVector Formalism, namely, that the experimenter's choice has been encrypted within the weak measurement's outcomes, even before the experimenter themselves knows what their choice will be. Causal loops are avoided by this anticipation remaining encrypted until the final outcomes enable to decipher it.
Self-assembly is an important process by which nontrivial structures are formed on the sub-micron scales. Such processes are governed by chemical and physical principles that dictate how the molecular interactions affect the supramolecular geometry. Currently there is no general framework that links between molecular properties and the supramolecular morphology with its size parameters. Here we introduce a new paradigm for the description and analysis of supramolecular structures that self-assemble via short-range interactions. Analysis of molecular interactions determines inputs to the theory of incompatible elasticity, which provides analytic expressions for supramolecular shape and fluctuations. We derive quantitative predictions for specific amphiphiles that self-assembled into chiral nanoribbons. These are quantitatively confirmed experimentally, revealing unique shape evolution, unusual mechanics and statistics, proving that the assemblies are geometrically incompatible. The success in predicting equilibrium and statistics suggests the approach as a new framework for quantitative study of a large variety of self-assembled nanostructures.
We derive a reduced quasi-one-dimensional theory of geometrically frustrated elastic ribbons. Expressed in terms of geometric properties alone, it applies to ribbons over a wide range of scales, allowing the study of their elastic equilibrium, as well as thermal fluctuations. We use the theory to account for the twisted-to-helical transition of ribbons with spontaneous negative curvature and the effect of fluctuations on the corresponding critical exponents. The persistence length of such ribbons changes nonmonotonically with the ribbon's width, dropping to zero at the transition. This and other statistical properties qualitatively differ from those of nonfrustrated fluctuating filaments.
In the last decade, potential exposure of humans and animals to industrial chemicals and pesticides has been a growing concern. In the present study, di-(2-ethylhexyl) phthalate (DEHP) and mono-(2-ethylhexyl) phthalate (MEHP) were used to model the effects of endocrine-disrupting compounds and their risk in relation to early embryonic losses. Exposure of cumulus oocyte complexes during maturation to 50 μM MEHP reduced the proportion of oocytes that underwent nuclear maturation (p < 0.05) and increased the proportion of apoptotic oocytes (p < 0.05). Furthermore, phthalates reduced cleavage rate in the MEHP-treated group (p < 0.05) and the proportion of embryos developing to the blastocyst stage in both DEHP- and MEHP-treated groups (p < 0.05). The total cell count for blastocysts developing from MEHP-treated oocytes was lower than in controls (p < 0.05). Exposure of oocytes to MEHP during maturation reduced (p < 0.05) the expression of ASAH1 (an anti-apoptotic factor), CCNA2 (involved in cell cycle control), and POU5F1 (responsible for pluripotency) in matured oocytes. Furthermore, the reduced mRNA expression of POU5F1 and ASAH1 lasted into two-cell stage embryos (p < 0.05). Phthalate-induced alterations in POU5F1, ASAH1, and CCNA2 expression might explain in part the reduced developmental competence of MEHP-treated oocytes.
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