Significant elastic anisotropy in Ti1−x_{1-x}Alx_xN alloys

Strong compositional-dependent elastic properties have been observed theoretically and experimentally in Ti$_{1-x}$Al$_x$ N alloys. The elastic constant, C$_{11}$, changes by more than 50% depending on the Al-content. Increasing the Al-content weakens the average bond strength in the local octahedral arrangements resulting in a more compliant material. On the other hand, it enhances the directional (covalent) nature of the nearest neighbor bonds that results in greater elastic anisotropy and higher sound velocities. The strong dependence of the elastic properties on the Al-content offers new insight into the detailed understanding of the spinodal decomposition and age hardening in Ti$_{1-x}$Al$_x$N alloys.Comment: 3 figures, 3 page

Temporal and population trends in human exploited pinnipeds from Tierra del Fuego

Archaeological sites on the coast of Tierra del Fuego, Argentina, provide a biogeochemical record that can inform us about those ecological dynamics. An abundance of southern fur seal (Arctocephalus australis) and southern sea lion (Otaria flavescens) remains provide a valuable resource to reconstruct ancient and modern food webs. To quantify ecological relationships, we measured bulk stable isotope ratios from bone collagen in otariids and other associated animals, several of which are potential otariid prey. Variations in bulk stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) are linked to potential dietary differences and habitat specialization between coastal areas or the open ocean in populations ranging in age from 7000 cal. Years BP to modern. We observed increases in the variability of these isotopic compositions over time, which suggests a diversity in the diets and habitats of otariids. Shifts in marine food webs occurred during the transition from subsistence hunting of otariids to industrial hunting and expanded human influence. We conclude that direct human influences, such as hunting and habitat alteration, were the major drivers of ecological change in southern South American marine ecosystems.Fil: Nye, Jonathan W.. University of California; Estados UnidosFil: Zangrando, Atilio Francisco Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Martinoli, Maria Paz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Fogel, Marilyn. University of California; Estados Unido

Cumulative Human Impacts on Pinnipeds Over the Last 7,500 Years in Southern South America

Our research program on this topic combines zooarchaeological and stable isotope studies from a historical ecology perspective. We originated this approach, and developed new analytical techniques, to better link archaeological evidence with paleo-ecosystem reconstructions (Zangrando, Panarello et al. 2014). In order to assess the relationship between pinnipeds and hunter-gatherers in Tierra del Fuego, we developed zooarchaeological analyses based on predictions from foraging models. Since information about past abundance or distribution of prey is rare in the southern South Atlantic, zooarchaeological evaluations were basedmainly on modern ecological parameters. Current foraging ecology of pinnipeds may be a useful framework for understanding archaeological evidence; however, that framework might present an incomplete picture of the actual range ofbehaviors and ecological roles that these resources could have provided for human populations in the past. In fact, the historical distribution of pinnipeds in Patagonia and Tierra del Fuego is poorly understood. Moreover, species distributions are likely to have fluctuated throughout time because of different environmental factors, or as a by-product of cumulative human impacts on marine ecosystems. Thus, the range of variation reflected in our knowledge about current pinniped distribution may not sufficiently represent the past.Against this context, an isotopic zooarchaeological approach provides a convenient route to expand our knowledge about human-pinniped relations at long-time scales (Zangrando,Panarello et al. 2014).Fil: Nye, Jonathan W.. University of California; Estados UnidosFil: Zangrando, Atilio Francisco Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Martinoli, Maria Paz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Vázquez, Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Fogel, Marilyn. University of California; Estados Unido

A comparison of collision cross section values obtained via travelling wave ion mobility-mass spectrometry and ultra high performance liquid chromatography-ion mobility-mass spectrometry : application to the characterisation of metabolites in rat urine

A comprehensive Collision Cross Section (CCS) library was obtained via Travelling Wave Ion Guide mobility measurements through direct infusion (DI). The library consists of CCS and Mass Spectral (MS) data in negative and positive ElectroSpray Ionisation (ESI) mode for 463 and 479 endogenous metabolites, respectively. For both ionisation modes combined, TWCCSN2 data were obtained for 542 non-redundant metabolites. These data were acquired on two different ion mobility enabled orthogonal acceleration QToF MS systems in two different laboratories, with the majority of the resulting TWCCSN2 values (from detected compounds) found to be within 1% of one another. Validation of these results against two independent, external TWCCSN2 data sources and predicted TWCCSN2 values indicated to be within 1-2% of these other values. The same metabolites were then analysed using a rapid reversed-phase ultra (high) performance liquid chromatographic (U(H)PLC) separation combined with IM and MS (IM-MS) thus providing retention time (tr), m/z and TWCCSN2 values (with the latter compared with the DI-IM-MS data). Analytes for which TWCCSN2 values were obtained by U(H)PLC-IM-MS showed good agreement with the results obtained from DI-IM-MS. The repeatability of the TWCCSN2 values obtained for these metabolites on the different ion mobility QToF systems, using either DI or LC, encouraged the further evaluation of the U(H)PLC-IM-MS approach via the analysis of samples of rat urine, from control and methotrexate-treated animals, in order to assess the potential of the approach for metabolite identification and profiling in metabolic phenotyping studies. Based on the database derived from the standards 63 metabolites were identified in rat urine, using positive ESI, based on the combination of tr, TWCCSN2 and MS data.</p

The Structure of the Plk4 Cryptic Polo Box Reveals Two Tandem Polo Boxes Required for Centriole Duplication

Centrioles are key microtubule polarity determinants. Centriole duplication is tightly controlled to prevent cells from developing multipolar spindles, a situation that promotes chromosomal instability. A conserved component in the duplication pathway is Plk4, a polo kinase family member that localizes to centrioles in M/G1. To limit centriole duplication, Plk4 levels are controlled through trans-autophosphorylation that primes ubiquitination. In contrast to Plks 1–3, Plk4 possesses a unique central region called the “cryptic polo box”. Here, we present the crystal structure of this region at 2.3 Å resolution. Surprisingly, the structure reveals two tandem, homodimerized polo boxes, PB1-PB2, that form a unique, winged architecture. The full PB1-PB2 cassette is required for binding the centriolar protein Asterless as well as robust centriole targeting. Thus, with its C-terminal polo box (PB3), Plk4 has a triple polo box architecture that facilitates oligomerization, targeting, and promotes trans-autophosphorylation, limiting centriole duplication to once per cell cycle

Two Polo-like kinase 4 binding domains in Asterless perform distinct roles in regulating kinase stability

Plk4 (Polo-like kinase 4) and its binding partner Asterless (Asl) are essential, conserved centriole assembly factors that induce centriole amplification when overexpressed. Previous studies found that Asl acts as a scaffolding protein; its N terminus binds Plk4’s tandem Polo box cassette (PB1-PB2) and targets Plk4 to centrioles to initiate centriole duplication. However, how Asl overexpression drives centriole amplification is unknown. In this paper, we investigated the Asl–Plk4 interaction in Drosophila melanogaster cells. Surprisingly, the N-terminal region of Asl is not required for centriole duplication, but a previously unidentified Plk4-binding domain in the C terminus is required. Mechanistic analyses of the different Asl regions revealed that they act uniquely during the cell cycle: the Asl N terminus promotes Plk4 homodimerization and autophosphorylation during interphase, whereas the Asl C terminus stabilizes Plk4 during mitosis. Therefore, Asl affects Plk4 in multiple ways to regulate centriole duplication. Asl not only targets Plk4 to centrioles but also modulates Plk4 stability and activity, explaining the ability of overexpressed Asl to drive centriole amplification

Changing spaces of political encounter and the rise of anti-politics: evidence from Mass Observation's General Election diaries

Negativity towards the institutions of formal politics is currently a concern across much of the democratic world. It is generally agreed that such negativity increased among British citizens during the second half of the twentieth century. In this paper, we analyse a novel dataset not previously used to study this topic: Mass Observation's General Election diaries. Since diarists wrote mostly about politicians, political campaigns, and associated media coverage, we ask specifically what the diaries can tell us about increased negativity towards politicians and its relationship to developments in political communication. We take a postholing approach to sampling of the diaries, enabling comparative-static analysis between the middle and end of the twentieth century. We view the diaries in a geographical framework derived from contextual theories of social action. This gives us a focus on spaces of political encounter, modes of political interaction, performances by politicians, and judgements by citizens. We argue that prominent spaces of political encounter changed over the period from long radio speeches and rowdy political meetings to televised debates and associated expert commentary. We demonstrate how these latter settings for political interaction afforded less opportunity for politicians to perform virtues to citizens, and for citizens to calibrate judgements of politicians

Painting the Nation:Examining the Intersection Between Politics and the Visual Arts Market in Emerging Economies

Politics and art have throughout history, intersected in diverse and complex ways. Ideologies and political systems have used the arts to create a certain image and, depending on the form of government this has varied from clear-cut state propaganda, to patronage, to more indirect arms-length funding procedures. Therefore, artists working within the macro-level socio-political context cannot help but be influenced, inspired and sometimes restricted by these policies and political influences. This article examines the contemporary art markets of two emerging, Socialist economies to investigate the relationship between state pol-itics and the contemporary visual arts market. We argue that the respective governments and art worlds are trying to construct a brand narrative for their nations, but that these discourses are often at cross-purposes. In doing so, we illustrate that it is impos-sible to separate a consideration of the artwork from the macro-level context in which it is produced, distributed, and consumed

A multinational case series describing successful treatment of persistent SARS-CoV-2 infection caused by Omicron sublineages with prolonged courses of nirmatrelvir/ritonavir.

The optimum treatment for persistent infection with SARS-CoV-2 is not known. Our case series, across 5 hospitals in 3 countries, describes 11 cases where persistent SARS-CoV-2 infection was successfully treated with prolonged courses (median 10 days, range 10-18) of nirmatrelvir/ritonavir (Paxlovid). Most cases (9/11) had haematological malignancy and ten (10/11) had received CD20 depleting therapy. The median duration of infection was 103 days (IQR 85-138). The majority (10/11) were hospitalised, and seven (7/11) had severe/critical disease. All survived and 9/11 demonstrated viral clearance, almost half (4/9) of whom received nirmatrelvir/ritonavir as monotherapy. This case series suggests prolonged nirmatrelvir/ritonavir has a role in treating persistent infection