Knut and Alice Wallenberg Foundation

A large number of V beta 8 gene-encoded cDNA were analyzed from peripheral CD4+ and CD8+ T cell subsets of T cell receptor (TcR) alpha chain-transgenic mice. This analysis demonstrates that a limited repertoire of TcR beta chains are co-expressed with the transgenic alpha chain. Most importantly, certain V beta 8-J beta combinations were found exclusively in one of the subsets and, in some cases, subset-specific differences were localized to the VDJ junctional region of the beta chain genes. In contrast, CD4-CD8- transgenic T cells, as well as CD4+ and CD8+ T cells from normal littermate controls, were found to express diverse beta chain repertoires. The present study suggests that beta chains with distinct structural characteristics are expressed in the CD4+ and CD8+ subsets, respectively. Moreover, the data suggest that the same structural constraints do not apply to the population of CD4-CD8- transgenic T cells.

Chalcogenide perovskites exhibit optoelectronic properties that position them as breakthrough materials in the field of photovoltaics. We report a detailed investigation into the electronic structure and chemical properties (XPS) of polycrystalline BaZrS3 perovskite powder, complemented by an analysis of their geometric atomic arrangement using XRD and XAS. The results are compared with measurements on sputtered polycrystalline BaZrS3 thin film prepared through rapid thermal processing. Moreover, we establish a correlation between the experimental valence band spectra and the theoretical density of states derived from DFT calculations, thereby discerning the orbital constituents involved. While bulk characterization confirms the good quality of the powder, depth-profiling achieved by photoelectron spectroscopy utilizing Al Kα (1.487 keV) and Ga Kα (9.25 keV) radiations shows that, regardless of the fabrication method, the oxidation effects extend beyond 10 nm from the sample surface, with specifically zirconium oxides occurring deeper than the oxidized sulfur species. The hard X-ray photoelectron spectroscopy study on the powder and thin film detects signals with minimal contamination contributions and allows the determination of the valence band maximum position with respect to the Fermi level. Our analysis gives an improved understanding of the electronic structure of BaZrS3, linking the electronic structure of this semiconductor to the fundamental bonding properties of the material, providing knowledge which is crucial for interfaces development, and consequently, for device integration.

Abstract Most people agree that we can have duties to prevent harm to others. But there is significant disagreement about what these duties demand of us and what they permit others to do to us. In Help! The Ethics of Rescue, Helen Frowe develops an account of the theoretical underpinnings of the duty to rescue. She rejects the influential view that the limits of the duty to rescue are explained by agent-relative prerogatives to care more about our own interests than the interests of others. In its place, she defends an agent-neutral account of the duty to rescue, grounded in the limits of the duty to use ourselves as a means for the benefit of others. Her account provides a unified, non-consequentialist account of the duty to rescue that tightly connects our right to refrain from saving to the wrongness of others forcing us to save. Frowe explores the implications of this agent-neutral account for a number of key debates in the ethics of rescue, such as the duty to act on lesser-evil justifications for harming, the moral significance of property rights over harm-preventing resources, and the permissibility of forming agreements to save. She also considers its implications for applied aspects of the duty to rescue, including the ethics of abortion, the ethics of war, and duties to refugees.

We investigate here the behaviour of a large typical meandric system, proving a central limit theorem for the number of components of given shape. Our main tool is a theorem of Gao and Wormald, that allows us to deduce a central limit theorem from the asymptotics of large moments of our quantities of interest.

We show that for many models of random trees, the independence number divided by the size converges almost surely to a constant as the size grows to infinity; the trees that we consider include random recursive trees, binary and $m$-ary search trees, preferential attachment trees, and others. The limiting constant is computed, analytically or numerically, for several examples. The method is based on Crump–Mode–Jagers branching processes.