On Determinants of Laplacians on Compact Riemann Surfaces Equipped with Pullbacks of Conical Metrics by Meromorphic Functions

Let $\mathsf m$ be any conical (or smooth) metric of finite volume on the Riemann sphere $\Bbb CP^1$. On a compact Riemann surface $X$ of genus $g$ consider a meromorphic funciton $f: X\to {\Bbb C}P^1$ such that all poles and critical points of $f$ are simple and no critical value of $f$ coincides with a conical singularity of $\mathsf m$ or $\{\infty\}$. The pullback $f^*\mathsf m$ of $\mathsf m$ under $f$ has conical singularities of angles $4\pi$ at the critical points of $f$ and other conical singularities that are the preimages of those of $\mathsf m$. We study the $\zeta$-regularized determinant $\operatorname{Det}' \Delta_F$ of the (Friedrichs extension of) Laplace-Beltrami operator on $(X,f^*\mathsf m)$ as a functional on the moduli space of pairs $(X, f)$ and obtain an explicit formula for $\operatorname{Det}' \Delta_F$.Comment: typos. arXiv admin note: text overlap with arXiv:1612.0866

A simplified approach to disulfide connectivity prediction from protein sequences

<p>Abstract</p> <p>Background</p> <p>Prediction of disulfide bridges from protein sequences is useful for characterizing structural and functional properties of proteins. Several methods based on different machine learning algorithms have been applied to solve this problem and public domain prediction services exist. These methods are however still potentially subject to significant improvements both in terms of prediction accuracy and overall architectural complexity.</p> <p>Results</p> <p>We introduce new methods for predicting disulfide bridges from protein sequences. The methods take advantage of two new decomposition kernels for measuring the similarity between protein sequences according to the amino acid environments around cysteines. Disulfide connectivity is predicted in two passes. First, a binary classifier is trained to predict whether a given protein chain has at least one intra-chain disulfide bridge. Second, a multiclass classifier (plemented by 1-nearest neighbor) is trained to predict connectivity patterns. The two passes can be easily cascaded to obtain connectivity prediction from sequence alone. We report an extensive experimental comparison on several data sets that have been previously employed in the literature to assess the accuracy of cysteine bonding state and disulfide connectivity predictors.</p> <p>Conclusion</p> <p>We reach state-of-the-art results on bonding state prediction with a simple method that classifies chains rather than individual residues. The prediction accuracy reached by our connectivity prediction method compares favorably with respect to all but the most complex other approaches. On the other hand, our method does not need any model selection or hyperparameter tuning, a property that makes it less prone to overfitting and prediction accuracy overestimation.</p

Vote choice in one round and two round elections

Nous proposons un modèle de vote stratégique dans lequel la décision de supporter ou non un candidat dépend de B, le bénéfice associé à l'élection de ce candidat, et de V, la viabilité perçue du candidat. Nous testons ce modèle sur des données obtenues lors d'une série d'expériences dans les quelles les participants votaient dans huit élections successives, quatre suivant la règle de vote à un seul tour, et quatre suivant le vote à deux tours. Nous montrons que le même modèle s'applique aux deux systèmes, bien que l'impact de la viabilité soit légèrement plus faible dans le cas des élections à deux tours.Elections, système de vote, comportement stratégique

Élections expérimentales : la désertion stratégique et la participation sous différents modes de scrutin

Cette thèse s'intéresse au lien qui existe entre le système électoral et deux comportements importants de la vie civique, soit la participation à une élection et la désertion stratégique du candidat préféré vers un autre candidat. Ces thèmes sont abordés dans de nombreux et de très importants ouvrages en science politique. En passant par la théorie (Downs, 1957) jusqu'à des études de terrain par l'entremise de sondages (Abramson, 2010; Blais, 2010), diverses méthodologies ont été employées pour mieux expliquer les choix des électeurs. Ma contribution à l'avancement des connaissances dans ce domaine passe par l'usage de la méthode expérimentale pour mieux saisir les similitudes et différences dans les comportements des électeurs sous le système uninominal à un tour (UT) et la représentation proportionnelle (RP) ainsi que les mécanismes au niveau individuel qui produisent ces similitudes et différences. Le cœur de la thèse est composé des trois articles dont voici les résumés : Article 1. Des élections expérimentales faites à Montréal, Paris et Bruxelles permettent d'estimer l’influence directe du mode de scrutin sur la décision des électeurs de voter ou non, et de voter pour leur parti préféré ou non. En tout, 16 groupes de 21 électeurs votent sous différents systèmes électoraux, soit le UT et la RP. Les préférences sont attribuées aléatoirement et connues de tous les participants. Nos résultats indiquent que le vote n'est pas globalement plus sincère et que la participation électorale n'est pas plus élevée sous le système proportionnel. Toutefois, nous observons moins de désertion d'un petit parti sous le système proportionnel. Article 2. Les expériences permettent également d'expliquer pourquoi les électeurs votent parfois pour un parti autre que leur parti préféré. La conclusion principale est que la décision de voter de façon sincère ou non est influencée par les préférences individuelles, mais aussi par les perceptions des chances de gagner des candidats ainsi que des chances que son propre vote puisse décider le résultat de l'élection. Les électeurs qui désertent leur premier choix prennent en considération quel candidat est le plus près de leurs positions politiques, mais également de la viabilité de cette alternative. De plus, les électeurs qui aiment prendre des risques ont davantage tendance à déserter. Article 3. Le modèle de l'électeur pivot est mis à l'épreuve pour mieux comprendre la décision de voter ou non lors d'une élection. Nos expériences permettent de répliquer, avec un devis expérimental différent, les résultats importants des travaux de Duffy et Tavits (2008). Nos résultats confirment que la perception d'être pivot augmente la participation, que ces perceptions sont sujettes à la surestimation et que cette surestimation ne décline pas complètement dans le temps. Nous allons également plus loin que les recherches de Duffy et Tavits et nous trouvons que la participation n'est pas plus forte sous RP que sous UT et que la probabilité d'être pivot a un impact plus important chez les électeurs évitant de prendre des risques.This thesis focuses on the relationship between the electoral system and two important behaviors of civic life: participation in an election and the strategic desertion of the preferred candidate. These topics are addressed in very important books in political science. From theory (Duverger, 1954; Downs, 1957) to empirical research using surveys (Abramson, 2010; Blais, 2010), various methodologies have been used to better explain voter's choices. My contribution to knowledge is the use of experimental methods to better understand both similarities and differences in voter behavior under the plurality system (PLU) and the proportional representation (PR) system and the individual level mechanisms that produce these similarities and differences. The core of the thesis consists of three articles summarized below: Article 1. Experimental elections conducted in Montreal, Paris and Brussels estimate the direct influence of the voting system on the voters' decision whether to vote or not, and vote for their preferred party or another party. In all, 16 groups of 21 voters take part in elections under different electoral systems. The systems are simple plurality and proportional representation. Preferences are randomly assigned and known by all participants. Our results indicate that voting is globally not more sincere and that voter turnout is not higher under the proportional system. However, we observe less desertion of small parties under the proportional system. Article 2. We perform a laboratory experiment to explain why voters sometimes vote for a party other than the preferred one. The main conclusion of the paper is that in addition to voter preferences, perceptions of winning chances and belief in the possibility of affecting the outcome are key factors in the voter’s decision to vote sincerely or not. When they desert their first choice, voters consider their preferences and the viability of the alternatives. Voters who like to take risks are more prone to desert. Article 3. This paper examines the decision to vote or not in experimental elections. We replicate the important findings of Duffy and Tavits (2008) with a different design. Our results support their finding, that is, turnout is affected by the belief that one's vote counts and overestimation of the probability that one's vote counts does not decrease completely over time. Going beyond previous research, we also find that turnout is not higher under a proportional system than under a plurality system, and beliefs about being in a pivotal disposition have a greater impact on turnout among the risk averse

A Presumptive Developmental Role for a Sea Urchin Cyclin B Splice Variant

We show that a splice variant–derived cyclin B is produced in sea urchin oocytes and embryos. This splice variant protein lacks highly conserved sequences in the COOH terminus of the protein. It is found strikingly abundant in growing oocytes and cells committed to differentiation during embryogenesis. Cyclin B splice variant (CBsv) protein associates weakly in the cell with Xenopus cdc2 and with budding yeast CDC28p. In contrast to classical cyclin B, CBsv very poorly complements a triple CLN deletion in budding yeast, and its microinjection prevents an initial step in MPF activation, leading to an important delay in oocyte meiosis reinitiation. CBsv microinjection in fertilized eggs induces cell cycle delay and abnormal development. We assume that CBsv is produced in growing oocytes to keep them in prophase, and during embryogenesis to slow down cell cycle in cells that will be committed to differentiation

Extreme viral partitioning in a marine-derived High Arctic lake

ABSTRACT High-latitude, perennially stratified (meromictic) lakes are likely to be especially vulnerable to climate warming because of the importance of ice in maintaining their water column structure and associated distribution of microbial communities. This study aimed to characterize viral abundance, diversity, and distribution in a meromictic lake of marine origin on the far northern coast of Ellesmere Island, in the Canadian High Arctic. We collected triplicate samples for double-stranded DNA (dsDNA) viromics from five depths that encompassed the major features of the lake, as determined by limnological profiling of the water column. Viral abundance and virus-to-prokaryote ratios were highest at greater depths, while bacterial and cyanobacterial counts were greatest in the surface waters. The viral communities from each zone of the lake defined by salinity, temperature, and dissolved oxygen concentrations were markedly distinct, suggesting that there was little exchange of viral types among lake strata. Ten viral assembled genomes were obtained from our libraries, and these also segregated with depth. This well-defined structure of viral communities was consistent with that of potential hosts. Viruses from the monimolimnion, a deep layer of ancient Arctic Ocean seawater, were more diverse and relatively abundant, with few similarities to available viral sequences. The Lake A viral communities also differed from published records from the Arctic Ocean and meromictic Ace Lake in Antarctica. This first characterization of viral diversity from this sentinel environment underscores the microbial richness and complexity of an ecosystem type that is increasingly exposed to major perturbations in the fast-changing Arctic. IMPORTANCE The Arctic is warming at an accelerating pace, and the rise in temperature has increasing impacts on the Arctic biome. Lakes are integrators of their surroundings and thus excellent sentinels of environmental change. Despite their importance in the regulation of key microbial processes, viruses remain largely uncharacterized in Arctic lacustrine environments. We sampled a highly stratified meromictic lake near the northern limit of the Canadian High Arctic, a region in rapid transition due to climate change. We found that the different layers of the lake harbored viral communities that were strikingly dissimilar and highly divergent from known viruses. Viruses were more abundant in the deepest part of the lake containing ancient Arctic Ocean seawater that was trapped during glacial retreat and were genomically unlike any viruses previously described. This research demonstrates the complexity and novelty of viral communities in an environment that is vulnerable to ongoing perturbation

Archives et sciences sociales

Séminaire collectif sous la responsabilité d’Éric Brian, Jean Jamin, directeurs d’étudesMorgane Labbé, Pap Ndiaye, maîtres de conférencesVincent Duclert, professeur agrégé Expériences III La première séance de l’année a porté sur le rôle et l’importance des archives dans l’édition. Animée par Vincent Duclert et Jean Jamin, elle a donné successivement la parole à Jacques Revel qui a longtemps co-dirigé la collection « Archives » de Julliard/Gallimard, puis à Hugues Pradier qui dirige actuellem..

Culex genome is not just another genome for comparative genomics

Formal publication of the Culex genome sequence has closed the human disease vector triangle by meeting the Anopheles gambiae and Aedes aegypti genome sequences. Compared to these other mosquitoes, Culex quinquefasciatus possesses many specific hallmark characteristics, and may thus provide different angles for research which ultimately leads to a practical solution for controlling the ever increasing burden of insect-vector-borne diseases around the globe. We argue the special importance of the cosmopolitan species- Culex genome sequence by invoking many interesting questions and the possible of potential of the Culex genome to answer those

Effect of the supporting electrolyte anion on the thickness of PSS/PAH multilayer films and on their permeability to an electroactive probe.

Quartz crystal microbalance and cyclic voltammetry are used to investigate the influence of the supporting salt of polyelectrolyte solutions on the buildup and the structure of PSS/PAH polyelectrolyte multilayers (PSS: poly(4-styrene sulfonate); PAH: poly(allylamine hydrochloride)). This film constitutes a model polyelectrolyte multilayer system. The supporting electrolytes were sodium salts where the nature of the anion was changed by following the Hofmeister series from cosmotropic to chaotropic anions (F-, Cl-, NO3-, ClO4-). For all the investigated anions, the film thickness increases linearly with the number of deposition steps.Wefind that chaotropic anions lead to larger thickness increments per bilayer during the film buildup than cosmotropic ones, confirming results found on PSS/PDADMA multilayers (PDADMA:poly(diallyldimethylammonium)). Films constituted by more than nine PSS/PAH bilayers are still permeable to hexacyanoferrate(II) ions, Fe(CN)(6)4-, whatever the nature of the supporting salt anion. On the other hand, these films are impermeable to ruthenium(II) hexamine ions, Ru(NH3)(6)2+, after the third PAH layer in the presence of NaF, NaCl, or NaNO3. These results are explained by the presence of an excess of positive charges in the film, which leads to a positive Donnan potential. We find that this potential is more positive when more chaotropic anions are used during the film buildup. We also find that a film constructed in the presence of chaotropic anions swells and becomes more permeable to Fe(CN)(6)4- ions when the film is brought into contact with a solution containing more cosmotropic anions. All our experimental findings can be explained by a strong interaction between chaotropic anions with the NH3+groups of PAH that is equivalent, as far as the multilayer buildup and electrochemical response is concerned, to a deprotonation of PAH as it is observed when the film is constructed at a higher pH. We thus arrive to a coherent explanation of the effect of the nature of the anions of the supporting electrolyte on the polyelectrolyte multilayer. We also find that great care must be taken when investigating polyelectrolyte multilayer films by electrochemical probing because electrochemical reactions involving the probes can appreciably modify the multilayer structure.journal articleresearch support, non-u.s. gov't2009 Feb 17importe