Search results for "Statistica"
showing 10 items of 5969 documents
New insight into the aptamer conformation and aptamer/protein interaction by surface-enhanced Raman scattering and multivariate statistical analysis
2021
International audience; We study the interaction between one aptamer and its analyte (the MnSOD protein) by the combination of surface-enhanced Raman scattering and multivariate statistical analysis. We observe the aptamer structure and its evolution during the interaction under different experimental conditions (in air or in buffer). Through the spectral treatment by principal component analysis of a large set of SERS data, we were able to probe the aptamer conformations and orientations relative to the surface assuming that the in-plane nucleoside modes are selectively enhanced. We demonstrate that the aptamer orientation and thus its flexibility rely strongly on the presence of a spacer …
Quantifying the limits of transition state theory in enzymatic catalysis
2017
Significance Transition state theory (TST) is the most popular theory to calculate the rates of enzymatic reactions. However, in some cases TST could fail due to the violation of the nonrecrossing hypothesis at the transition state. In the present work we show that even for one of the most controversial enzymatic reactions—the hydride transfer catalyzed by dihydrofolate reductase—the error associated to TST represents only a minor correction to the reaction rate. Moreover, this error is actually larger for the reaction in solution than in the enzymatic active site. Based on this finding and on previous studies we propose an “enzymatic shielding” hypothesis which encompasses various aspects …
Reply to "comment on 'Monte Carlo simulations for a Lotka-type model with reactant surface diffusion and interactions' ".
2002
As is well known, a wide class of physical problems, including the kinetics of heterogeneous catalytic reactions, is traditionally described in terms of the master equations ~ME!. The definition of ME allows us not only to perform Monte Carlo ~MC! simulations, but also to develop at the same time appropriate analytical methods @mean field~MF!, cluster approximations, etc. #@ 1#. ME is formally defined when all possible states of a system and the transition rates between these states are specified. This is enough to define only the transition rates K(i! j ) for such elementary processes as particle adsorption, desorption, diffusion, reaction, etc., from the initial state i to the final state…
Spherically averaged versus angle-dependent interactions in quadrupolar fluids
2008
Employing simplified models in computer simulation is on the one hand often enforced by computer time limitations but on the other hand it offers insights into the molecular properties determining a given physical phenomenon. We employ this strategy to the determination of the phase behaviour of quadrupolar fluids, where we study the influence of omitting angular degrees of freedom of molecules via an effective spherically symmetric potential obtained from a perturbative expansion. Comparing the liquid-vapor coexistence curve, vapor pressure at coexistence, interfacial tension between the coexisting phases, etc., as obtained from both the models with the full quadrupolar interactions and th…
Modelling the timing of divorce in Italy: a survival analysis on regression quantiles
2011
The analysis of marital dissolution in Italy represents a quite interesting and challenging topic from a substantive standpoint; in fact, despite of the decreasing number of marriages and the increasing number of divorces, the traditional family based on the marriage of heterosexual partners is still considered as a fundamental institution of the society. Here we present a censored quantile regression model with additive terms to investigate the determinants of the timing of marital dissolution on a large and substantial sample from a survey carried on in Italy.
Short implants (8mm) versus longer implants (≥8mm) with lateral sinus floor augmentation in posterior atrophic maxilla: A meta-analysis of RCT`s in h…
2019
Background One of the greatest challenges that dentists face today is to rehabilitate severe atrophied alveolar ridges in partially and completely edentulous patients with implants. Despite the high survival rate of implants placed next to sinus elevation, this technique presents complications that can be avoided by placing short implants, an option that also presents high survival rates. For this reason, the aim of this study is to compare the survival rate, marginal bone loss and complications associated with short implants (<8 mm) versus longer implants (≥8mm) placed with lateral sinus floor elevation in posterior atrophic maxillae. Material and Methods A literature search was conducted …
Composite Indicator of Social Inclusion for European Countries
2013
Social inclusion is one of the key challenges of the European Union (EU) Sustainable Development Strategy. We use four indicators from EU policies to measure social inclusion for the 27 member countries of Europe. In particular, we aggregate the four indicators in a multiplicative composite indicator via a DEA-BoD approach with weights determined endogenously with proportion constraints. We obtain a score of social inclu- sion that allows us to grade the 27 EU countries from 2006 to 2010. In this way, we highlight the specific role played by the four indicators in determining improvements and deteriorations of social inclusion during the European phase of the financial and economic crisis.
Composite Indicator of Social Inclusion for the EU Countries
2016
Social inclusion is one of the key challenges of the European Union Sustainable Development Strategy (EU SDS). We use the main indicators identified by Eurostat within the operational objectives of the specific European policies to measure social inclusion for the 27 member countries of the European Union. In particular, we aggregate four basic indicators in a multiplicative composite indicator via a DEA-BoD approach with weights determined endogenously with proportion constraints. We obtain a score of social inclusion that allows us to grade the 27 EU countries from 2006 to 2010. In this way, we highlight the specific role played by the four indicators in determining improvements and deter…
Contributions of statistical modelling for the understanding of the nivo-glaciological dynamics of a small arctic glacial basin (Austre Lovén glacier…
2021
Since the middle of the 19th century, the Earth has experienced a climate shift marked by a high rise in temperature (+ 0.85 °C over the period 1880-2012). The Arctic is the region of the world that is warming the most rapidly, at a rate of 2 to 3 times faster than the global average. In this context, all components of the Arctic cryosphere are experiencing a change in their dynamics. Because of their direct links with the atmosphere, glaciers are among the best indicators of these climate variations. Like other glaciers on the globe, the glaciers of Svalbard, which cover 60% of the archipelago’s surface, have been retreating since the end of the Little Ice Age. This retreat, which is refle…
La misura dello sviluppo locale
2007
Negli anni '70 lo sviluppo locale si presenta in Italia in una forma e con una forza che non richiedono nuovi e specifici strumenti di misura. Sono i distretti industriali nelle regioni della "terza italia" a imporsi in quegli anni alla riflessione economica e sociologica, perchè determinano in modo significativo le economie regionali e dunque le misure regionali dell'economia e del mercato del lavoro. dagli anni '90, però, lo sviluppo locale diventa uno degli strumenti delle politiche per le aree depresse. I sistemi locali del lavoro, strumenti di misura costruiti per la delimitazione e identificazione dei distretti industriali, si rilevano inadeguati a cogliere i fenomeni deboli e circost…