1,062 research outputs found

    On The Nature of Contract

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    The Basis of Contractual Obligation: An Essay in Speculative Jurisprudence

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    Lawyers as Agents

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    This article addresses the nature and effect of the agency relationship that exists between a lawyer and his client. There are two aspects of this, the internal relationship and its external effects. Under the first heading are considered the duties of the lawyer towards his client, including his fiduciary duties, which have recently been broadened, and the obligation of the client to pay his lawyer. The external aspect of a lawyer's role as agent for his client raises the issue of the agent's authority which may be express, implied or apparent. The scope of that authority is vital. It is analysed in respect of two different situations. The first is where no litigation is involved, but the lawyer is required to deal with money on behalf of the client, contracts within the Statute of Frauds, or notices. The second relates to the conduct of litigation. A number of important issues arise in this respect, of which the most important is the authority of a lawyer to compromise or settle an action. This is considered in some depth with special reference to English and Canadian cases, in order to elucidate the extent to which and grounds upon which a lawyer may validly affect his client's position.L 'article suivant étudie la nature et les conséquences des relations d'agence qui existent entre un avocat et son client. On envisage deux aspects principaux: les relations internes et les conséquences externes. Le premier thème traite des obligations de l'avocat envers son client y compris les obligations fiduciaires, qui ont été elargies récemment, et de la responsabilité du client de régler les honoraires de son avocat. L'aspect externe du rôle de l'avocat, comme agent de son client, soulève la question de l'autorité de l'agent qui peut être expresse, implicite ou apparente. L'étendue de cette autorité est d'importance capitale. On l'analyse en tenant compte de deux situations différentes: La première n 'implique aucun litige, plutôt l'avocat doit s'occuper des affires de son client, des contrats dans le cadre du Statute of Frauds, ou des préavis. La deuxième situation sa rapport à la conduite du litige. De nombreuses questions se présentent, la plus importante étant l'autorité de l ’avocat de régler une cause par compromis, ou de la résoudre. On a réfléchit longuement à ces questions en tenant compte des arrêts Anglais et Canadiens, afin de pouvoir élucider dans quelle mesure et sous quel motif un avocat peut affecter la position de son client

    A generic C1C^1 map has no absolutely continuous invariant probability measure

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    Let MM be a smooth compact manifold (maybe with boundary, maybe disconnected) of any dimension d≥1d \ge 1. We consider the set of C1C^1 maps f:M→Mf:M\to M which have no absolutely continuous (with respect to Lebesgue) invariant probability measure. We show that this is a residual (dense Gδ)setintheG_\delta) set in the C^1$ topology. In the course of the proof, we need a generalization of the usual Rokhlin tower lemma to non-invariant measures. That result may be of independent interest.Comment: 12 page

    An Intelligent Safety System for Human-Centered Semi-Autonomous Vehicles

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    Nowadays, automobile manufacturers make efforts to develop ways to make cars fully safe. Monitoring driver's actions by computer vision techniques to detect driving mistakes in real-time and then planning for autonomous driving to avoid vehicle collisions is one of the most important issues that has been investigated in the machine vision and Intelligent Transportation Systems (ITS). The main goal of this study is to prevent accidents caused by fatigue, drowsiness, and driver distraction. To avoid these incidents, this paper proposes an integrated safety system that continuously monitors the driver's attention and vehicle surroundings, and finally decides whether the actual steering control status is safe or not. For this purpose, we equipped an ordinary car called FARAZ with a vision system consisting of four mounted cameras along with a universal car tool for communicating with surrounding factory-installed sensors and other car systems, and sending commands to actuators. The proposed system leverages a scene understanding pipeline using deep convolutional encoder-decoder networks and a driver state detection pipeline. We have been identifying and assessing domestic capabilities for the development of technologies specifically of the ordinary vehicles in order to manufacture smart cars and eke providing an intelligent system to increase safety and to assist the driver in various conditions/situations.Comment: 15 pages and 5 figures, Submitted to the international conference on Contemporary issues in Data Science (CiDaS 2019), Learn more about this project at https://iasbs.ac.ir/~ansari/fara

    Formation Mechanisms for Spirals in Barred Galaxies

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    We consider a scenario of formation of the spiral structure in barred galaxies. This scenario includes the new non-resonant mechanism of elongation of spirals, due to the characteristic behaviour of the gravitational potential beyond the principal spiral arms

    Mechanisms of the Vertical Secular Heating of a Stellar Disk

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    We investigate the nonlinear growth stages of bending instability in stellar disks with exponential radial density profiles.We found that the unstable modes are global (the wavelengths are larger than the disk scale lengths) and that the instability saturation level is much higher than that following from a linear criterion. The instability saturation time scales are of the order of one billion years or more. For this reason, the bending instability can play an important role in the secular heating of a stellar disk in the zz direction. In an extensive series of numerical NN-body simulations with a high spatial resolution, we were able to scan in detail the space of key parameters (the initial disk thickness z0z_0, the Toomre parameter QQ, and the ratio of dark halo mass to disk mass Mh/MdM_{\rm h} / M_{\rm d}). We revealed three distinct mechanisms of disk heating in the zz direction: bending instability of the entire disk, bending instability of the bar, and heating on vertical inhomogeneities in the distribution of stellar matter.Comment: 22 pages including 8 figures. To be published in Astronomy Letters (v.29, 2003

    Reaction rate reconstruction from biomass concentration measurement in bioreactors using modified second-order sliding mode algorithms

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    This paper deals with the estimation of unknown signals in bioreactors using sliding observers. Particular attention is drawn to estimate the specific growth rate of microorganisms from measurement of biomass concentration. In a recent article, notions of high-order sliding modes have been used to derive a growth rate observer for batch processes. In this paper we generalize and refine these preliminary results. We develop a new observer with a different error structure to cope with other types of processes. Furthermore, we show that these observers are equivalent, under coordinate transformations and time scaling, to the classical super-twisting differentiator algorithm, thus inheriting all its distinctive features. The new observers’ family achieves convergence to timevarying unknown signals in finite time, and presents the best attainable estimation error order in the presence of noise. In addition, the observers are robust to modeling and parameter uncertainties since they are based on minimal assumptions on bioprocess dynamics. In addition, they have interesting applications in fault detection and monitoring. The observers performance in batch, fed-batch and continuous bioreactors is assessed by experimental data obtained from the fermentation of Saccharomyces Cerevisiae on glucose.This work was supported by the National University of La Plata (Project 2012-2015), the Agency for the Promotion of Science and Technology ANPCyT (PICT2007-00535) and the National Research Council CONICET (PIP112-200801-01052) of Argentina; the Technical University of Valencia (PAID-02-09), the CICYT (DPI2005-01180) and AECID (A/024186/09) of Spain; and by the project FEDER of the European Union.De Battista, H.; Picó Marco, JA.; Garelli, F.; Navarro Herrero, JL. (2012). Reaction rate reconstruction from biomass concentration measurement in bioreactors using modified second-order sliding mode algorithms. Bioprocess and Biosystems Engineering. 35(9):1-11. https://doi.org/10.1007/s00449-012-0752-yS111359Aborhey S, Williamson D (1978) State amd parameter estimation of microbial growth process. Automatica 14:493–498Bastin G, Dochain D (1986) On-line estimation of microbial specific growth rates. Automatica 22:705–709Bastin G, Dochain D (1990) On-line estimation and adaptive control of bioreactors. Elsevier, AmsterdamBejarano F, Fridman L (2009) Unbounded unknown inputs estimation based on high-order sliding mode differentiator. In: Proceedings of the 48th IEEE conference on decision and control, pp 8393–8398Corless M, Tu J (1998) State and input estimation for a class of uncertain systems. Automatica 34(6):757–764Dabros M, Schler M, Marison I (2010) Simple control of specific growth rate in biotechnological fed-batch processes based on enhanced online measurements of biomass. Bioprocess Biosyst Eng 33:1109–1118Davila A, Moreno J, Fridman L (2010) Variable gains super-twisting algorithm: a lyapunov based design. In: American control conference (ACC), 2010, pp 968–973Dávila J, Fridman L, Levant A (2005) Second-order sliding-mode observer for mechanical systems. IEEE Transact Automatic Control 50(11):1785–1789De Battista H, Picó J, Garelli F, Vignoni A (2011) Specific growth rate estimation in (fed-)batch bioreactors using second-order sliding observers. J Process Control 21:1049–1055Dochain D (2001) Bioprocess control. Wiley, HobokenDochain D (2003) State and parameter estimation in chemical and biochemical processes: a tutorial. J Process Control 13(8):801–818Edwards C, Spurgeon S, Patton R (2000) Sliding mode observers for fault detection and isolation. 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IEEE Transact Automatic Control 37(6):875–880Gnoth S, Jenzsch M, Simutis R, Lubbert A (2008) Control of cultivation processes for recombinant protein production: a review. Bioprocess Biosyst Eng 31(1):21–39Hitzmann B, Broxtermann O, Cha Y, Sobieh O, Stärk E, Scheper T (2000) The control of glucose concentration during yeast fed-batch cultivation using a fast measurement complemented by an extended kalman filter. Bioprocess Eng 23(4):337–341Kiviharju K, Salonen K, Moilanen U, Eerikainen T (2008) Biomass measurement online: the performance of in situ measurements and software sensors. J Indus Microbiol Biotechnol 35(7):657–665Levant A (1998) Robust exact differentiation via sliding mode technique. Automatica 34(3):379–384Levant A (2003) Higher-order sliding modes, differentiation and output-feedback control. Int J Control 76(9/10):924–941Lubenova V, Rocha I, Ferreira E (2003) Estimation of multiple biomass growth rates and biomass concentration in a class of bioprocesses. Bioprocess Biosyst Eng 25:395–406Moreno J, Alvarez J, Rocha-Cozatl E, Diaz-Salgado J (2010) Super-twisting observer-based output feedback control of a class of continuous exothermic chemical reactors. In: Proceedings of the 9th IFAC international symposium on dynamics and control of process systems, pp 719–724. Leuven, BelgiumMoreno J, Osorio M (2008) A Lyapunov approach to second-order sliding mode controllers and observers. In: Proceedings of the 47th IEEE conference on decision and control. Cancún, México, pp 2856–2861Moreno J, Osorio M (2012) Strict Lyapunov functions for the super-twisting algorithm. IEEE Transact Automatic Control 57:1035–1040Navarro J, Picó J, Bruno J, Picó-Marco E, Vallés S (2001) On-line method and equipment for detecting, determining the evolution and quantifying a microbial biomass and other substances that absorb light along the spectrum during the development of biotechnological processes. 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    Stable Models of Elliptical Galaxies

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    We construct stable axially symmetric models of elliptical galaxies. The particle density on phase space for these models depends monotonically on the particle energy and on the third component of the angular momentum. They are obtained as minimizers of suitably defined energy-Casimir functionals, and this implies their nonlinear stability. Since our analysis proceeds from a rigorous but purely mathematical point of view it should be interesting to determine if any of our models match observational data in astrophysics. The main purpose of these notes is to initiate some exchange of information between the astrophysics and the mathematics communities.Comment: 26 page

    Genome-wide data from medieval German Jews show that the Ashkenazi founder event pre-dated the 14th century

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    We report genome-wide data for 33 Ashkenazi Jews (AJ), dated to the 14th century, following a salvageexcavation at the medieval Jewish cemetery of Erfurt, Germany. The Erfurt individuals are geneticallysimilar to modern AJ and have substantial Southern European ancestry, but they show more variabilityin Eastern European-related ancestry than modern AJ. A third of the Erfurt individuals carried the samenearly-AJ-specific mitochondrial haplogroup and eight carried pathogenic variants known to affect AJtoday. These observations, together with high levels of runs of homozygosity, suggest that the Erfurtcommunity had already experienced the major reduction in size that affected modern AJ. However, theErfurt bottleneck was more severe, implying substructure in medieval AJ. Together, our results suggestthat the AJ founder event and the acquisition of the main sources of ancestry pre-dated the 14th centuryand highlight late medieval genetic heterogeneity no longer present in modern AJ
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