“Johnny Came to College to get an Education – He Found Romance Anyway”: The Unconventional Wartime Story of John and Marie Renza

Among the long list of economic, social, and political changes that American society experienced during the World War II era was a trend toward whirlwind romances, courtships, and marriages. The pressures of war, namely the conscription of most able-bodied American men, placed many young couples in precarious positions as they faced a long-term separation, names a “courtship by mail,” or a hasty marriage. Marie Teigue and John Renza, both wartime graduates of Bryant College, bucked the trends of their age. The Renzas were a couple that fell in love, grew apart, grew up, and found each other again on their own terms, against the backdrop of World War II, and not because of it

On the capacity achieving covariance matrix for Rician MIMO channels: an asymptotic approach

The capacity-achieving input covariance matrices for coherent block-fading correlated MIMO Rician channels are determined. In this case, no closed-form expressions for the eigenvectors of the optimum input covariance matrix are available. An approximation of the average mutual information is evaluated in this paper in the asymptotic regime where the number of transmit and receive antennas converge to $+\infty$. New results related to the accuracy of the corresponding large system approximation are provided. An attractive optimization algorithm of this approximation is proposed and we establish that it yields an effective way to compute the capacity achieving covariance matrix for the average mutual information. Finally, numerical simulation results show that, even for a moderate number of transmit and receive antennas, the new approach provides the same results as direct maximization approaches of the average mutual information, while being much more computationally attractive.Comment: 56 pp. Extended version of the published article in IEEE Inf. Th. (march 2010) with more proof

Full radiative coupling in two-phase models for accreting black holes

The emission from galactic black holes and Seyfert galaxies is generally understood in term of two-phase models (Haardt and Maraschi 1991, 1993). Such models postulate that a hot plasma coexists with relatively colder material in the inner part of the accretion flow. We present the first simulated broad-band spectra produced by such a system and accounting simultaneously for energy balance and Comptonisation in the hot phase, together with reflection, reprocessing, ionization and thermal balance in the cold phase. This was made possible by coupling three radiative transfer codes: a non-linear Monte-Carlo code (NLMC), a photo-ionization code TITAN and a linear Monte-Carlo code NOAR. The equilibrium comptonisation spectrum appears to be sensitive to the shape of the reprocessed spectrum that, in turn, depends on the ionization parameter, but also on the structure of the irradiated cold material. This is illustrated by a comparison of simulations assuming constant density or a constant pressure in the cold phase. We also compare our results with simplified models where reprocessing is approximated by a blackbody spectrum. Our detailed treatment leads to noticeably different spectral energy distributions (SEDs) characterised by harder X-ray spectra. Even at low ionization parameters the commonly used blackbody approximation is poor, leading to X-ray spectra that are too soft. The effect, however, seems not to be strong enough to reconcile the slab corona model with the hardest observed spectra, unless the reflector has a constant density and the ionization parameter is large.Comment: 11 pages, 5 figures, to appear in A&

SiNx:Tb3+--Yb3+, an efficient down-conversion layer compatible with a silicon solar cell process

SiN x : Tb 3+-Yb 3+, an efficient down-conversion layer compatible with silicon solar cell process Abstract Tb 3+-Yb 3+ co-doped SiN x down-conversion layers compatible with silicon Photovoltaic Technology were prepared by reactive magnetron co-sputtering. Efficient sensitization of Tb 3+ ions through a SiN x host matrix and cooperative energy transfer between Tb 3+ and Yb 3+ ions were evidenced as driving mechanisms of the down-conversion process. In this paper, the film composition and microstructure are investigated alongside their optical properties, with the aim of maximizing the rare earth ions incorporation and emission efficiency. An optimized layer achieving the highest Yb 3+ emission intensity was obtained by reactive magnetron co-sputtering in a nitride rich atmosphere for 1.2 W/cm${}^2$ and 0.15 W/cm${}^2$ power density applied on the Tb and Yb targets, respectively. It was determined that depositing at 200 {\textdegree}C and annealing at 850 {\textdegree}C leads to comparable Yb 3+ emission intensity than depositing at 500 {\textdegree}C and annealing at 600 {\textdegree}C, which is promising for applications toward silicon solar cells.Comment: Solar Energy Materials and Solar Cells, Elsevier, 201

p90Rsk is not involved in cytostatic factor arrest in mouse oocytes

Vertebrate oocytes arrest in metaphase of the second meiotic division (MII), where they maintain a high cdc2/cyclin B activity and a stable, bipolar spindle because of cytostatic factor (CSF) activity. The Mos–MAPK pathway is essential for establishing CSF. Indeed, oocytes from the mos−/− strain do not arrest in MII and activate without fertilization, as do Xenopus laevis oocytes injected with morpholino oligonucleotides directed against Mos. In Xenopus oocytes, p90Rsk (ribosomal S6 kinase), a MAPK substrate, is the main mediator of CSF activity. We show here that this is not the case in mouse oocytes. The injection of constitutively active mutant forms of Rsk1 and Rsk2 does not induce a cell cycle arrest in two-cell mouse embryos. Moreover, these two mutant forms do not restore MII arrest after their injection into mos−/− oocytes. Eventually, oocytes from the triple Rsk (1, 2, 3) knockout present a normal CSF arrest. We demonstrate that p90Rsk is not involved in the MII arrest of mouse oocytes

Articuler histoire et informatique, enseignement et recherche : le PIREH de l’université Panthéon-Sorbonne

La création et l’activité du Pôle informatique de recherche et d’enseignement en histoire (PIREH) de l’université Paris 1 Panthéon-Sorbonne s’inscrivent dans une tradition d’utilisation des outils informatiques et statistiques en histoire depuis la création de l’université en 1971. Cet article revient sur ses acteurs, leurs enseignements, leurs productions (revues, logiciels) dans les années 1970-1980, en les replaçant dans le contexte intellectuel et technique de l’époque. La création du PIREH en 1999 permet de structurer cette activité et ces formations (autour notamment des bases de données, de la lexicométrie et de l’analyse factorielle des correspondances). Depuis la fin des années 1990, ces pratiques et les enseignements qui y sont liés se diversifient, à la faveur du développement du Web, d’un meilleur accès à des outils variés et de collaborations interdisciplinaires auxquelles participe le PIREH. L’esquisse de cette histoire nous permet in fine de définir ce qui caractérise l’approche de l’informatique dans le travail pédagogique et scientifique du PIREH.The Center for Computing in History (Pôle informatique de recherche et d’enseignement en histoire, PIREH) of Paris 1 Panthéon-Sorbonne University is rooted in a tradition of using statistics and computer sciences in History since the creation of this university in 1971. This paper first presents the people involved in this field at Paris 1 in the 1970-1980s, their teaching, and their work (journals, software), by replacing them in the intellectual and technical context of the time. The creation of the PIREH in 1999 reinforced this movement and structured a curriculum based on the use of databases, text analysis and factorial analysis in History. Since the late 1990s, the activity of the PIREH is diversifying, in response to the development of the Web, to the availability of new and more accessible computing tools, and to several interdisciplinary collaborations. By retracing this history, one can better grasp the specific use the PIREH makes of computing for teaching and researching History

Kinetochore component function in C. elegans oocytes revealed by 4D tracking of holocentric chromosomes

During cell division, chromosome congression to the spindle center, their orientation along the spindle long axis and alignment at the metaphase plate depend on interactions between spindle microtubules and kinetochores, and are pre-requisite for chromosome bi-orientation and accurate segregation. How these successive phases are controlled during oocyte meiosis remains elusive. Here we provide 4D live imaging during the first meiotic division in C. elegans oocytes with wild-type or disrupted kinetochore protein function. We show that, unlike in monocentric organisms, holocentric chromosome bi-orientation is not strictly required for accurate chromosome segregation. Instead, we propose a model in which initial kinetochore-localized BHC module (comprised of BUB-1Bub1, HCP-1/2CENP-F and CLS-2CLASP)-dependent pushing acts redundantly with Ndc80 complex-mediated pulling for accurate chromosome segregation in meiosis. In absence of both mechanisms, homologous chromosomes tend to co-segregate in anaphase, especially when initially mis-oriented. Our results highlight how different kinetochore components cooperate to promote accurate holocentric chromosome segregation in oocytes of C. elegans.This work was supported by CNRS and University ParisCité, by NIHR01GM117407 and R01GM130764 (J.C.C.), and by grants from the European Research Council ERC-CoG ChromoSOMe 819179 and from the Agence Nationale de la Recherche ANR-19-CE13-0015 (J.D.).Peer ReviewedPostprint (published version

Pile à combustible, production d'hydrogène à partir de biomasse, stockage d'hydrogène sur carbones nanostructurés, analyse du cycle de vie : un projet du groupe des Ecoles des Mines en génie des procédés, énergie et environnement (GEM GP E2)

International audienceLes équipes de différents centres de recherche des Ecoles des Mines, impliquées dans les domaines liés à la filière hydrogène, se sont regroupées au sein du Groupe des Ecoles des Mines en Génie des Procédés, Energie et Environnement (GEM GP E2). Le projet H2-PAC mis en place, a ainsi permis de regrouper les compétences de ces équipes pour aborder de manière plus efficace les quatre problématiques suivantes : les piles à combustible à membrane échangeuse de protons, la production d'hydrogène à partir de biomasse, le stockage d'hydrogène sur matériaux carbonés nanostructurés et l'analyse du cycle de vie. Dans chacun de ces thèmes des progrès ont été enregistrés et les équipes se sont mutuellement enrichies de nouvelles connaissances. Le projet a dans l'ensemble permis de créer des liens entre les différentes équipes impliquées, qui permettront de futures collaborations et la concrétisation de nouveaux projets

A centriole- and RanGTP-independent spindle assembly pathway in meiosis I of vertebrate oocytes

Spindle formation is essential for stable inheritance of genetic material. Experiments in various systems indicate that Ran GTPase is crucial for meiotic and mitotic spindle assembly. Such an important role for Ran in chromatin-induced spindle assembly was initially demonstrated in Xenopus laevis egg extracts. However, the requirement of RanGTP in living meiotic cells has not been shown. In this study, we used a fluorescence resonance energy transfer probe to measure RanGTP-regulated release of importin β. A RanGTP-regulated gradient was established during meiosis I and was centered on chromosomes throughout mouse meiotic maturation. Manipulating levels of RanGTP in mice and X. laevis oocytes did not inhibit assembly of functional meiosis I spindles. However, meiosis II spindle assembly did not tolerate changes in the level of RanGTP in both species. These findings suggest that a mechanism common to vertebrates promotes meiosis I spindle formation in the absence of chromatin-induced microtubule production and centriole-based microtubule organizing centers