Behavioural analysis of web building anomalies in the orb-weaving spider Zygiella x-notata (Araneae, Araneidae)

Among animal constructions, spider’s orb webs represent regular geometrical architecture models. Their construction is the result of successive, simple and reproducible behavioural patterns, often considered as stereotyped. It has recently been shown that spider’s building behaviours vary, which can alter web regularity. The final capture spiral results from the laying of successive threads between two radii, here termed ‘spiral units’. We defined a theoretical normal web, as a web in which each turn of the final spiral should be parallel to the preceding one. Weaving of the spiral units sometimes leads to anomalies in the orb web. Anomalies were identified and analysed in the orb-weaving spider Zygiella x-notata (Clerck, 1757). From video recordings of web construction, we noted the displacements of the legs and of the abdomen of the spider. We compared the frequency of displacements, and their duration, between the construction of spiral units that produce a normal turn and ones that produce an anomalous turn. The position of the legs on the web’s threads was also analysed. Results showed that anomalies were not the consequences of a modification in activity but more likely the result of the position on the radii of the fourth leg. These results suggest that spiders use local information to build the final capture spiral

Invariant Variation Problems

The problems in variation here concerned are such as to admit a continuous group (in Lie's sense); the conclusions that emerge from the corresponding differential equations find their most general expression in the theorems formulated in Section 1 and proved in following sections. Concerning these differential equations that arise from problems of variation, far more precise statements can be made than about arbitrary differential equations admitting of a group, which are the subject of Lie's researches. What is to follow, therefore, represents a combination of the methods of the formal calculus of variations with those of Lie's group theory. For special groups and problems in variation, this combination of methods is not new; I may cite Hamel and Herglotz for special finite groups, Lorentz and his pupils (for instance Fokker), Weyl and Klein for special infinite groups. Especially Klein's second Note and the present developments have been mutually influenced by each other, in which regard I may refer to the concluding remarks of Klein's Note.Comment: M. A. Tavel's English translation of Noether's Theorems (1918), reproduced by Frank Y. Wang. Thanks to Lloyd Kannenberg for corrigend

L’honnête homme et le libertin. Le topos de l’innocente séduite dans les derniers romans de l’abbé Prévost.

Le thème de l'innocente menacée, récurrent dans l'oeuvre de Prévost, fait l'objet d'une même anecdote rapportée dans les Mémoires d'un honnête homme (1745) et dans le Monde moral (l 760), anecdote racontée respectivement par la victime et par le libertin séducteur. Ces deux versions, apparemment complémentaires, correspondent pour Prévost à deux manières d'appréhender le phénomène libertin, à des moments différents de sa production. Leur comparaison permet d'interroger le discours oblique qui est tenu sur le libertinage dans ces textes, en particulier les non-dits et les résistances des narrateurs vertueux (qui s'érigent en juges du « désordre ») et la fantasmagorie de ces épisodes (la figure du père libertin, séducteur incestueux, ressort de l'histoire des Mémoires d'un honnête homme , tandis que le récit du Monde moral exhibe la faillite de tout libertinage conquérant). Prévost propose en termes de séduction et de censure une vision critique d'un libertinage contaminé, en quelque sorte, par le moralisme des deux narrateurs qui ne savent que gémir sur la dépravation des moeurs. N'est-ce pas un moyen pour Prévost de traduire certaines angoisses liées au comportement libertin - exhibition phallique, si l'on considère le modèle de Don juan ? Cette hypothèse permettrait de reconsidérer le libertinage immature de des Grieux ou le libertinage velléitaire de l'ambassadeur de l'Histoire d'une Grecque moderne. Après 1740, les tentations libertines apparaissent chez Prévost sous forme d'obsessions et de désirs de violences sexuelles plus ou moins refoulés.The theme of innocence threatened or corrupted by seduction recurs in the novels of Prévost. The story appears both in his Mémoires d'unhonnête homme (1745) and in le Monde moral(1760), recounted respectively by the victim of seduction and the seducer. These two, apparently complementary, versions correspond to two ways in which Prévost grasps the phenomenon of the libertine at different moments of its emergence. A comparison of the texts reveals the characteristics of Prévost's oblique discourse on libertinism, with its unuttered motives, slippages and resistances, particularly by the virtuous narrators who set themselves up as moral arbiters of the action. Prévost uses terms of seduction and censure to put forward a critical vision of libertinage touched, as it were, by moralism. The two episodes are notable also for their underlying fantasies: the figure of the libertine father, the incestuous seducer, in Mémoires d'un honnête homme, and the bankruptcy of all-devouring libertinism in le Monde moral, where Prévost evokes some of the psychic aspects of phallic exhibition. Our interpretation should shed new light on the immature libertinage of des Grieux, as well as on its wavering pursuit by the ambassador in l'Histoire d'une Grecque moderne. After 1740, seduction appears in Prévost's novels in the guise of more or less inhibited obsessions and desires for sexual violence

De quelques réflexions sur l’article 48 du Code de procédure civile, envisagé au travers de « la loi du maximum de différence entre le droit du Traité et la loi interne »

National audienc

La pratique de la médiation familiale judiciaire : étude menée dans le ressort de la cour d'appel d'Aix-en-Provence

International audienceChapeau : Alors que la médiation familiale est prévue pour tous les contentieux soumis au JAF, cette étude nous propose un état des lieux chiffré de sa pratique au sein des juridictions de la cour d'appel d'Aix-en-Provence, afin de voir dans quelle mesure une meilleure effectivité de ce mécanisme pourrait être rendue possible. Sources :merci, le cas échéant, de positionner le curseur ci-dessous, puisde sélectionner le type de source correspondant dans le bandeau [Texte] La médiation familiale, processus structuré, par lequel des parties tentent de trouver un accord en vue de la résolution amiable de leur différend avec l'aide d'un tiers impartial, le médiateur choisi par elle ou désigné par les juges aux affaires familiales, a été intégrée dans le Code civil, respectivement en 2002, en matière d'autorité parentale, à l'article 373-2-1, et, en 2004, en matière de divorce, à l'article 255 du Code civil. Ces textes offrent aux juges aux affaires familiales (JAF) la faculté soit d'ordonner une médiation lorsque les parties y consentent, soit de leur faire injonction de rencontrer un médiateur familial qui les informera sur le processus de médiation. À cela, il faut ajouter l'article 1071 du Code de procédure civile (CPC) qui dispose, d'une manière plus générale, que le juge aux affaires familiales saisi d'un litige peut proposer une mesure de médiation et après avoir recueilli l'accord des parties, désigner un médiateur familial pour y procéder, et encore enjoindre aux parties de rencontrer un médiateur. En définitive, ce sont tous les contentieux soumis au JAF qu

Maintenance of polymorphism in the orb weaving spider species Agalenatea redii (Araneae, Araneidae)

The maintenance of polymorphism within populations may be the consequence of several elements of species life history such as use of space, activity rhythms, predation, parasitism and reproduction. The present study focuses on the latter aspect using an orb weaving spider, Agalenatea redii, which presents five different morphs of the opisthosoma pattern in the adult stage. Over the course of four years, from 2008 to 2011, adult spiders (males, females and pairs) were observed at different sites. In 2011, we also conducted a six-week survey of a single population, observing the number of spiders of each morph and the morph of paired spiders. We collected field data on the spatial and temporal distribution of spiders based on their sex and morph. Using a distance analysis, we compared the field distribution with a simulated one in which pairs were associated at random. The results showed that although there were changes over time and space in the proportions of females of the different morphs, as well as in the proportion of the pair associations, pairing according to morphs probably occurs at random

La médiation familiale : une voie d'apaisement des conflits familiaux

International audienceLa médiation familiale, processus de construction ou de reconstruction du lien familial mené par un tiers qualifié, le médiateur familial, et axé sur l'autonomie des personnes concernées par des situations de rupture ou de séparation n'est pas un mode de règlement du litige mais une voie d'apaisement du conflit familial. Elle invite les juristes à un changement de culture et s'inscrit dans un mouvement législatif plus général qui cherche à valoriser la résolution amiable des différends. Les litiges familiaux représentent aujourd'hui près de la moitié du contentieux devant les tribunaux civils, qu'il s'agisse de questions touchant à la séparation des couples comme de celles relatives à l'organisation des relations parents-enfants (Rapp. Sénat n° 404, Justice aux affaires familiales : pour un règlement pacifié des litiges, 26 févr. 2014, 2013-2014, p. 14). Ces procédures sont souvent longues, violentes, et il n'est pas rare qu'une fois le procès achevé, le conflit subsiste. Pour ne prendre qu'un exemple, la proportion de divorces par consentement mutuel revenant devant le juge serait en effet de 40 %, d'après un rapport sur la justice familiale, établi en2014 (Rapp. Sénat n° 404, Justice aux affaires familiales : pour un règlement pacifié des litiges, précité, p.51), ce qui montre bien que la pacification des procédures de divorce espérée par le législateur après l'adoption de la réforme de 2004 (L. n° 2004-439, 26 mai 2004, JO 27 mai 2004) n'est souvent qu'apparente ! Cela invite à réfléchir sur les limites du système judiciaire dans sa forme classique. C'est en prenant la mesure de ce problème que le législateur a introduit la médiation familiale dans le Code civil, au début du XXI e siècle

Influence of the Stereochemical Structure on The Physicochemical Properties of Polymers Prepared by Ring-Opening Polymerization of Chiral Heterocyclic Monomers

Physico-chemical properties of polymers prepared by ringopening polymerization of heterocyclic chiral monomers with different enantiomeric composition are compared. Two general kinds of behaviour were observed for products with a monosubstituted carbon in the chain: when the substituent group is not bulky the properties of polyenantiomers and their racemic mixture are very similar ; when the substituent is a bulky group, e. g. t-butyl, many of the properties (m.p., crystalline structure, solubility, etc.) are very different for the same polymers. The corresponding statistical stereocopolymers are amorphous. For polymers with disubstituted asymmetric carbon atoms the statistical stereocopolymers are crystalline and their melting behaviour varies with the enantiomeric purity. In some cases a strong dependence of the mechanical and biological properties on the enantiomeric purity of stereocopolymers is reported

New insights into the tonoplast architecture of plant vacuoles and vacuolar dynamics during osmotic stress

BACKGROUND: The vegetative plant vacuole occupies >90% of the volume in mature plant cells. Vacuoles play fundamental roles in adjusting cellular homeostasis and allowing cell growth. The composition of the vacuole and the regulation of its volume depend on the coordinated activities of the transporters and channels localized in the membrane (named tonoplast) surrounding the vacuole. While the tonoplast protein complexes are well studied, the tonoplast itself is less well described. To extend our knowledge of how the vacuole folds inside the plant cell, we present three-dimensional reconstructions of vacuoles from tobacco suspension cells expressing the tonoplast aquaporin fusion gene BobTIP26-1::gfp. RESULTS: 3-D reconstruction of the cell vacuole made possible an accurate analysis of large spanning folds of the vacuolar membrane under both normal and stressed conditions, and suggested interactions between surrounding plastids. Dynamic, high resolution 3-D pictures of the vacuole in tobacco suspension cells monitored under different growth conditions provide additional details about vacuolar architecture. The GFP-decorated vacuole is a single continuous compartment transected by tubular-like transvacuolar strands and large membrane surfaces. Cell culture under osmotic stress led to a complex vacuolar network with an increased tonoplast surface area. In-depth 3-D realistic inspections showed that the unity of the vacuole is maintained during acclimation to osmotic stress. Vacuolar unity exhibited during stress adaptation, coupled with the intimate associations of vacuoles with other organelles, suggests a physiological role for the vacuole in metabolism, and communication between the vacuole and organelles, respectively, in plant cells. Desiccation stress ensuing from PEG treatment generates "double" membrane structures closely linked to the tonoplast within the vacuole. These membrane structures may serve as membrane reservoirs for membrane reversion when cells are reintroduced to normal growth conditions. CONCLUSION: 3-D processing of a GFP-labeled tonoplast provides compelling visual constructions of the plant cell vacuole and elaborates on the nature of tonoplast folding and architecture. Furthermore, these methods allow real-time determination of membrane rearrangements during stresses

Modified methods for voltage-sag source detection using transient periods

Real-time detection of the voltage sag sources' relative location requires fast and accurate methods. Therefore, in this paper, the transient period of voltage sags is used with useful detection information, which is not considered in the literature. In this context, this work firstly analyses the main positive-sequence phasor-based (PB) and instantaneous-based (IB) methods within both transient and steady-state periods of voltage sags caused by network faults and transformer energizing. Secondly, new methods are proposed using five different modifiers, applied in the transient period of voltage sags, i.e., half and one cycle time windows, to achieve a faster and more accurate response. These modifiers use the PB/IB criteria obtained from the existing methods, such as power, impedance, and current, and are applied as: The mean of the criterion changes, the first largest peak (FLP) on the criterion changes, the mean of the zero-mean criteria during a sag, the FLP of the zero-mean criteria during a sag, and the Trend (slope) of criteria's trajectories versus time. Voltage sag source detection methods are evaluated by applying 1992 simulated voltage sag events in a Brazilian regional power network. The results reveal that the proposed modifiers, used in the new methods, improve the ineffective existing methods by taking half/one cycle within a transient period of voltage sags. The modifiers also show an accuracy equal to other existing enhanced methods due to employing them within the transient period, thus evidencing their appropriateness. Correspondingly, a selection is made amongst the new modified methods in order to choose the most accurate time window (half or one cycle) for the methods. The selected modified methods are also tested by applying field measurements in a Slovenian power network to confirm their effectiveness in the transient short periods. According to a recommendation of the fastest and most accurate new methods in this study, an important application can be using the recommended methods as the directional function in the relays, along with an accurate voltage sag/fault inception time detection algorithm in real-time