Electroweak Measurements of Neutron Densities in CREX and PREX at JLab, USA

Measurement of the parity-violating electron scattering asymmetry is an established technique at Jefferson Lab and provides a new opportunity to measure the weak charge distribution and hence pin down the neutron radius in nuclei in a relatively clean and model-independent way. This is because the Z boson of the weak interaction couples primarily to neutrons. We will describe the PREX and CREX experiments on ${}^{208}$Pb and ${}^{48}$Ca respectively; these are both doubly-magic nuclei whose first excited state can be discriminated by the high resolution spectrometers at JLab. The heavier lead nucleus, with a neutron excess, provides an interpretation of the neutron skin thickness in terms of properties of bulk neutron matter. For the lighter ${}^{48}$Ca nucleus, which is also rich in neutrons, microscopic nuclear theory calculations are feasible and are sensitive to poorly constrained 3-neutron forces.Comment: A contribution to the upcoming EPJA Special Volume on Nuclear Symmetry Energ

Spatial control of irreversible protein aggregation

Liquid cellular compartments spatially segregate from the cytoplasm and can regulate aberrant protein aggregation, a process linked to several medical conditions, including Alzheimer's and Parkinson's diseases. Yet the mechanisms by which these droplet-like compartments affect protein aggregation remain unknown. Here, we combine kinetic theory of protein aggregation and liquid-liquid phase separation to study the spatial control of irreversible protein aggregation in the presence of liquid compartments. We find that, even for weak interactions between the compartment constituents and the aggregating monomers, aggregates are strongly enriched inside the liquid compartment relative to the surrounding cytoplasm. We show that this enrichment is caused by a positive feedback mechanism of aggregate nucleation and growth which is mediated by a flux maintaining the phase equilibrium between the compartment and the cytoplasm. Our model predicts that the compartment volume that maximizes aggregate enrichment in the compartment is determined by the reaction orders of aggregate nucleation. The underlying mechanism of aggregate enrichment could be used to confine cytotoxic protein aggregates inside droplet-like compartments suggesting potential new avenues against aberrant protein aggregation. Our findings could also represent a common mechanism for the spatial control of irreversible chemical reactions in general

The Holding-Dictum Spectrum

Presumably, the terms holding and dictum have some objective meaning. One would not say, “I do not agree with this statement, so it is dictum.” One might say, “This statement is dictum, so it is not binding.” So what, then, is dictum? More specifically, to what extent does the breadth of a generalization affect its status as holding or dictum

The Patent Lawyer’s Guide to Fascism

This essay presents an unusual and potentially valuable way of thinking about the patent system. It is worth considering the ways in which the structure of private law may affect our susceptibility to undesirable forms of societal organization. This essay considers how a well-structured patent system could potentially reduce our susceptibility to fascism by: (1) promoting an ethos of independent creative thought, and (2) facilitating market entry by startups, thereby reducing market concentration and possibly reducing authoritarian hierarchy. One legitimate utilitarian aim of the patent system might be to thus promote horizontal individualism, which could tend to work against fascism’s extremely nationalistic vertical collectivism. Promotion of individual autonomy might be an under-recognized benefit of the patent system, suggesting a valuable lens through which to view not only patent law, but also other areas of private law