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Imposing a magnetic field on a turbulent flow of electrically conducting fluid incurs the Joule effect. A current paradigm is that the corresponding dissipation increases with the intensity of the magnetic field, and as a result turbulent fluctuations are all the more damped as the magnetic field is strong. While this idea finds apparent support in the phenomenology of decaying turbulence, measurements of turbulence in duct flows and other, more complex configurations have produced seemingly contradicting results. The root of the controversy is that magnetic fields promote sufficient scale-dependent anisotropy to profoundly reorganise the structure of turbulence, so their net effect cannot be understood in terms of the additional dissipation only. Here we show that when turbulence is forced in a magnetic field that acts on turbulence itself rather than on the mechanisms that generate it, the field promotes large, nearly 2D structures capturing sufficient energy to offset the loss due to Joule dissipation, with the net effect of increasing the intensity of turbulent fluctuations. This change of paradigm potentially carries important consequences for systems as diverse as the liquid cores of planets, accretion disks and a wide range of metallurgical and nuclear engineering applications.

This paper introduces an experimental apparatus, which drives turbulence electrically in a liquid metal pervaded by a high magnetic field. Unlike past magnetohydrodynamic (MHD) setups involving a shallow confinement, the experiment presented here drives turbulence whose dimensionality can be set anywhere between three-dimensional and quasi two-dimensional. In particular, we show that the dimensionality and componentality of the turbulence thus generated are in fact completely fixed by the single parameter lz(li)/h, which quantifies the competition between the solenoidal component of the Lorentz force and inertia acting on a turbulent structure of the size of the forcing scale li. This parameter is fully tunable thanks to the three operating settings at hand: the injection scale, the intensity of the electric forcing and the magnitude of the magnetic field. Thanks to the very high number of measuring probes and fast acquisition rate implemented in this experiment, it is possible to reliably measure the finest features of the inertial range on a scale-wise basis.

Spleen tyrosine kinase (SYK) is a critical immune signaling molecule and therapeutic target. We identified damaging monoallelic SYK variants in six patients with immune deficiency, multi-organ inflammatory disease such as colitis, arthritis and dermatitis, and diffuse large B cell lymphomas. The SYK variants increased phosphorylation and enhanced downstream signaling, indicating gain of function. A knock-in (SYK-Ser544Tyr) mouse model of a patient variant (p.Ser550Tyr) recapitulated aspects of the human disease that could be partially treated with a SYK inhibitor or transplantation of bone marrow from wild-type mice. Our studies demonstrate that SYK gain-of-function variants result in a potentially treatable form of inflammatory disease. Individuals with SYK gain-of-function variants develop immunodeficiency and systemic inflammation, which are recapitulated in a knock-in mouse model. Treatment of these mice with bone marrow transplantation or with a SYK inhibitor ameliorates disease symptoms, highlighting potential therapeutic strategies for patients with SYK mutations.

In scrapie-infected mice, prions are found associated with splenic but not circulating B and T lymphocytes and in the stroma, which contains follicular dendritic cells (FDCs). Formation and maintenance of mature FDCs require the presence of B cells expressing membrane-bound lymphotoxin-α/β. Treatment of mice with soluble lymphotoxin-β receptor results in the disappearance of mature FDCs from the spleen. We show that this treatment abolishes splenic prion accumulation and retards neuroinvasion after intraperitoneal scrapie inoculation. These data provide evidence that FDCs are the principal sites for prion replication in the spleen.

Although prion proteins are most efficiently propagated through intracerebral inoculation, peripheral administration has caused the diseases kuru, iatrogenic Creutzfeldt-Jakob disease (CJD), bovine spongiform encephalopathy (BSE) and new-variant CJD. The development of neurological disease after peripheral inoculation depends on prion expansion within cells of the lympho-reticular system. Here we investigate the identity of these cells by using a panel of immune-deficient mice inoculated with prions intraperitoneally: we found that defects affecting only T lymphocytes had no apparent effect, but that all mutations that disrupted the differentiation and response of B lymphocytes prevented the development of clinical scrapie. As an absence of B cells and of antibodies correlates with severe defects in follicular dendritic cells, a lack of any of these three components may prevent the development of clinical scrapie. However, we found that scrapie developed after peripheral inoculation in mice expressing immunoglobulins that were exclusively of the M subclass and without detectable specificity for the normal form of the prion PrPc, and in mice which had differentiated B cells but no functional follicular dendritic cells. We conclude that differentiated B cells are crucial for neuroinvasion by scrapie, regardless of the specificity of their receptors.

El objetivo principal de este trabajo es presentar importantes novedades sobre el marco histórico y productivo de la explotación minera de la sierra de Corduba en época romana, así como de la gestión de sus recursos. Desde hace años y a partir de la documentación epigráfica disponible, se ha venido apuntando una posible presencia en este territorio de la societas Sisaponensis y de la explotación de plomo y plata por su parte, a pesar de la afamada vinculación con el beneficio del cinabrio que recoge un conocido pasaje de Plinio. Nuestras investigaciones en el norte de Córdoba y los análisis arqueométricos realizados sobre tres lingotes de plomo recuperados en el paraje de Los Escoriales de Doña Rama, situado en la Sierra de Gata (Belmez-Córdoba), suponen una superación de la frontera del conocimiento sobre los aspectos reseñados, ya que permiten contrastar estas dos hipótesis tradicionales y proponer nuevas cuestiones sobre la explotación de estos parajes y la actividad de esta societas . Estos lingotes fueron encontrados en una instalación minero-metalúrgica romana, algo que es excepcional, y conservan una inscripción, S S, que los vincula sin duda con la societas Sisaponensis. This article presents new information on the historical and productive context of mining exploration in the mountains of Corduba during Roman times, as well as on the management of resources. For as long as the epigraphic evidence has been known, it has been suggested that the societas Sisaponensis may have been present in the area and that it may have been involved in the production of lead and silver, despite its famous association with cinnabar exploitation, as mentioned in a well-known passage by Pliny the Elder. Our research in the north of Córdoba province and archaeometric analyses carried out on three lead ingots recovered from the site of Los Escoriales de Doña Rama, located in the Sierra de Gata (Belmez-Córdoba), advance our understanding of these problems, as they allow us to propose new questions about the exploitation of these sites and the activity of the societas . The ingots were found in a Roman mine-metallurgical facility, which is exceptional, and bear an inscription, S S, which undoubtedly links them to the societas Sisaponensis .