Metropolis simulations of Met-Enkephalin with solvent-accessible area parameterizations

We investigate the solvent-accessible area method by means of Metropolis simulations of the brain peptide Met-Enkephalin at 300$K$. For the energy function ECEPP/2 nine atomic solvation parameter (ASP) sets are studied. The simulations are compared with one another, with simulations with a distance dependent electrostatic permittivity $\epsilon (r)$, and with vacuum simulations ($\epsilon =2$). Parallel tempering and the biased Metropolis techniques RM$_1$ are employed and their performance is evaluated. The measured observables include energy and dihedral probability densities (pds), integrated autocorrelation times, and acceptance rates. Two of the ASP sets turn out to be unsuitable for these simulations. For all other systems selected configurations are minimized in search of the global energy minima, which are found for the vacuum and the $\epsilon(r)$ system, but for none of the ASP models. Other observables show a remarkable dependence on the ASPs. In particular, we find three ASP sets for which the autocorrelations at 300$$K are considerably smaller than for vacuum simulations.Comment: 10 pages and 8 figure

New Robust Obstacle Detection System Using Color Stereo Vision

Intelligent transportation systems (ITS) are divided into intelligent infrastructure systems and intelligent vehicle systems. Intelligent vehicle systems are typically classified in three categories, namely 1) Collision Avoidance Systems; 2) Driver Assistance Systems and 3) Collision Notification Systems. Obstacle detection is one of crucial tasks for Collision Avoidance Systems and Driver Assistance Systems. Obstacle detection systems use vehiclemounted sensors to detect obstuctions, such as other vehicles, bicyclists, pedestrians, road debris, or animals, in a vehicleâs path and alert the driver. Obstacle detection systems are proposed to help drivers see farther and therefore have more time to react to road hazards. These systems also help drivers to get a large visibility area when the visibility conditions is reduced such as night, fog, snow, rain, ... Obstacle detection systems process data acquired from one or several sensors: radar Kruse et al. (2004), lidar Gao & Coifman (2006), monocular vision Lombardi & Zavidovique (2004), stereo vision Franke (2000) Bensrhair et al. (2002) Cabani et al. (2006b) Kogler et al. (2006) Woodfill et al. (2007), vision fused with active sensors Gern et al. (2000) Steux et al. (2002) Mobus & Kolbe (2004)Zhu et al. (2006) Alessandretti et al. (2007)Cheng et al. (2007). It is clear now that most obstacle detection systems cannot work without vision. Typically, vision-based systems consist of cameras that provide gray level images. When visibility conditions are reduced (night, fog, twilight, tunnel, snow, rain), vision systems are almost blind. Obstacle detection systems are less robust and reliable. To deal with the problem of reduced visibility conditions, infrared or color cameras can be used. Thermal imaging cameras are initially used by militaries. Over the last few years, these systems became accessible to the commercial market, and can be found in select 2006 BMW cars. For example, vehicle headlight systems provide between 75 to 140 meters of moderate illumination; at 90 K meters per hour this means less than 4 seconds to react to hazards. When with PathFindIR PathFindIR (n.d.) (a commercial system), a driver can have more than 15 seconds. Other systems still in the research stage assist drivers to detect pedestrians Xu & Fujimura (2002) Broggi et al. (2004) Bertozzi et al. (2007). Color is appropriate to various visibility conditions and various environments. In Betke et al. (2000) and Betke & Nguyen (1998), Betke et al. have demonstrated that the tracking o

Water activity in liquid food systems : A molecular scale interpretation

Water activity has historically been and continues to be recognised as a key concept in the area of food science. Despite its ubiquitous utilisation, it still appears as though there is confusion concerning its molecular basis, even within simple, single component solutions. Here, by close examination of the well-known Norrish equation and subsequent application of a rigorous statistical theory, we are able to shed light on such an origin. Our findings highlight the importance of solute-solute interactions thus questioning traditional, empirically based “free water” and “water structure” hypotheses. Conversely, they support the theory of “solute hydration and clustering” which advocates the interplay of solute-solute and solute-water interactions but crucially, they do so in a manner which is free of any estimations and approximations

Dalla civil conversazione all'omelia: la parabola di Francesco Berni

Il saggio si occupa del Rifacimento berbiano dell'Orlando Innamorato di Matteo Maria Boiardo

Immagine e immaginazione nelle "Rime" del Tasso

Il saggio mette in evidenza la forte componente erotica presente nelle rime tassiane mettendola in parallelo con quella del poema

Riflessioni sparse su un poema molto commentato

L’intervento si sofferma sul commento di Emilio Bigi all’Orlando furioso (1982), recentemente riproposto da Cristina Zampese (2012), partendo da una breve storia della tradizione esegetica cinquecentesca del poema ariostesco. Mette poi in luce alcuni caratteri fondamentali del commento bigiano: ampiezza delle singole note, ricchezza di livelli di analisi (lessicale, stilistica, retorica, intra e intertestuale, variantistica, storico-biografica), conformità delle note a un’interpretazione globale del poema, che potremmo sintetizzare nella formula dell’“armonia conquistata”. Cabani si interroga infine su quale potrebbe essere la forma di un nuovo commento che, senza perdere la ricchezza di quello bigiano, pervenga a una maggior distinzione e a nuova distribuzione delle fasce esegetiche. In particolare, Cabani si chiede se e in quale parte dell’apparato critico intertestualità e variantistica debbano essere collocate a integrazione delle semplici note interpretative.This paper deals with Emilio Bigi’s commentary to the Orlando furioso (1982), recently reprinted by Cristina Zampese (2012). Starting with a short history of the sixteenth-century exegetical tradition, it dwells on some of the main features of Bigi’s commentary: the amplitude of the annotations, the richness of their analytical levels (lexical, stylistic, rhetorical, intra- and intertextual, historico-biographical, and its constant attention to variants), their compliance with a comprehensive interpretation of the poem, which might be defined as a “conquered harmony”. Lastly Cabani discusses what form and shape might take a future commentary to Ariosto’s poem, so that, without losing the richness of Bigi’s work, it might introduce a new arrangement in the explanatory apparatus, to be split into two or more distinct bands. In particular, she considers whether, and within which band of the apparatus, should be put the intertextual and variant reference, in order best to compliment the mere explanatory notes

Innovating ski resorts' business model through a human centered approach

Ski resorts from countries with a long ski tradition, mainly in Europe and North America, are experiencing signs of participation stagnancy during the past decades. Wondering how to tackle this issue, the researcher merged two paths of his career (business models and the ski resorts management) to come up with the following research question: How might ski resorts innovate their business models by putting special emphasis in customer empathy? This main question counted with three more specific questions, which at the same time, are the three parts that compose the thesis: Part 1: Foundations. How might the current business model literature help ski resorts to understand their current business model? The starting point consisted of a theoretical review of business models (definition, representation, and innovation) and ski resort industry (general overview of the industry and the existing business models). Part 2: Identifying opportunities. How might empathizing with customers help ski resorts identify opportunities for business model innovation? By deep understanding how people’s lives interact with ski resorts, one can identify their unmet needs or problems. In other words, through this approach, one could learn how ski resorts could be from the point of view of its users. Part 3: Seizing opportunities. How might ski resorts seize these identified opportunities by reconfiguring the existing business model? In orderThis part consisted of leveraging the identified needs into opportunities to innovate ski resorts’ business model. To do so, the researcher came up with solutions, built and test mock-ups out of them and implemented them into the business model. Problems Some problems emerged along the research, which made it even more challenging. Dealing with them tested the researcher’s rigor in the method as well as the capacity to adapt to unexpected situations. Among them, there is the underlying complexity of business models, limitations of time and resources and a high degree of ambiguity. Conclusions Reflecting upon the outcomes of the research, an industry found in a mature and stagnant state as the ski industry, has much more to win than to lose if they innovate their business model. What is more, they have a lot to lose if they do not challenge the status quo. Quoting the words of Frank Lloyd Wright: “Business is like riding a bicycle. Either you keep moving or you fall down.

Effect of the integration method on the accuracy and computational efficiency of free energy calculations using thermodynamic integration

Although calculations of free energy using molecular dynamics simulations have gained significant importance in the chemical and biochemical fields, they still remain quite computationally intensive. Furthermore, when using thermodynamic integration, numerical evaluation of the integral of the Hamiltonian with respect to the coupling parameter may introduce unwanted errors in the free energy. In this paper, we compare the performance of two numerical integration techniques-the trapezoidal and Simpson's rules and propose a new method, based on the analytic integration of physically based fitting functions that are able to accurately describe the behavior of the data. We develop and test our methodology by performing detailed studies on two prototype systems, hydrated methane and hydrated methanol, and treat Lennard-Jones and electrostatic contributions separately. We conclude that the widely used trapezoidal rule may introduce systematic errors in the calculation, but these errors are reduced if Simpson's rule is employed, at least for the electrostatic component. Furthermore, by fitting thermodynamic integration data, we are able to obtain precise free energy estimates using significantly fewer data points (5 intermediate states for the electrostatic component and 11 for the Lennard-Jones term), thus significantly decreasing the associated computational cost. Our method and improved protocol were successfully validated by computing the free energy of more complex systems hydration of 2-methylbutanol and of 4-nitrophenol-thus paving the way for widespread use in solvation free energy calculations of drug molecules

SuperpixelGridCut, SuperpixelGridMean and SuperpixelGridMix Data Augmentation

A novel approach of data augmentation based on irregular superpixel decomposition is proposed. This approach called SuperpixelGridMasks permits to extend original image datasets that are required by training stages of machine learning-related analysis architectures towards increasing their performances. Three variants named SuperpixelGridCut, SuperpixelGridMean and SuperpixelGridMix are presented. These grid-based methods produce a new style of image transformations using the dropping and fusing of information. Extensive experiments using various image classification models and datasets show that baseline performances can be significantly outperformed using our methods. The comparative study also shows that our methods can overpass the performances of other data augmentations. Experimental results obtained over image recognition datasets of varied natures show the efficiency of these new methods. SuperpixelGridCut, SuperpixelGridMean and SuperpixelGridMix codes are publicly available at https://github.com/hammoudiproject/SuperpixelGridMasksComment: The project is available at https://github.com/hammoudiproject/SuperpixelGridMask

Mise en correspondance couleur par programmation dynamique pour les véhicules intelligents

Dans cette communication, nous proposons un opérateur de détection de contours couleur rapide et auto-adaptatif ainsi q'un algorithme de mise en correspondance couleur par programmation dynamique pour les véhicules intélligents. Le but étant d'intégrer ce processus dans notre système de stéréo vision couleur en cours de conception afin d'extraire les contours 3D des obstacles. Dans une première étape, les points de contours sont extraits de façon auto-adaptative en utilisant l'opérateur déclivité couleur. Dans une deuxième étape, ces points de contours sont mis en correspondance par une méthode de programmation dynamique, en tenant compte des contraintes géométriques, colorimétriques, d'ordre et d'unicité. Les résultats de mise en correspondance sont des points de contours 3D