Search results for "Reso"
showing 10 items of 13841 documents
Comparison of different theory models and basis sets in the calculation of 13C NMR chemical shifts of natural products.
2004
The influence of the calculation method in mimicking experimental 13C NMR chemical shifts of 15 low-polarity natural products singularly containing 10–20 carbon atoms was investigated by employing different quantum chemistry approaches and basis sets, both in the preliminary geometry optimizations and in the following single-point 13C GIAO calculations of the NMR chemical shifts. The geometries of the involved species were optimized at the PM3, HF, B3LYP and mPW1PW91 levels whereas the 13C NMR parameters were determined at the HF, B3LYP and mPW1PW91 levels. Different combinations of basis sets were also tested. The consistency and efficiency of the considered combinations of geometry optimi…
Four-Component Relativistic DFT Calculations of C-13 Chemical Shifts of Halogenated Natural Substances
2015
We have calculated the (13) C NMR chemical shifts of a large ensemble of halogenated organic molecules (81 molecules for a total of 250 experimental (13) C NMR data at four different levels of theory), ranging from small rigid organic compounds, used to benchmark the performance of various levels of theory, to natural substances of marine origin with conformational degrees of freedom. Carbon atoms bonded to heavy halogen atoms, particularly bromine and iodine, are known to be rather challenging when it comes to the prediction of their chemical shifts by quantum methods, due to relativistic effects. In this paper, we have applied the state-of-the-art four-component relativistic density funct…
Food community networks as sustainable self-organized collective action: A case study of a Solidarity Purchasing Group
2014
The spread of Food Community Networks (FCNs) is mainly due to new and confirmed policies for consumption, testing new social paradigms aimed at promoting sustainable development in rural areas through the active reorganization of the agricultural and food industry. As a result, there is a set of rules deriving from complex relational structures competing to define self-organized collective action for sustainability. This paper analyses the structure of relations within FCNs. With this end in view, research on the experience of FCNs has been done, in particular of Solidarity Purchasing Groups (henceforth SPGs) in Sicily (Southern Italy). By applying Social Network Analysis, the article ident…
A classification of motivation and behavior change techniques used in self-determination theory-based interventions in health contexts
2020
While evidence suggests that interventions based on self-determination theory have efficacy in motivating adoption and maintenance of health-related behaviors, and in promoting adaptive psychological outcomes, the motivational techniques that comprise the content of these interventions have not been comprehensively identified or described. The aim of the present study was to develop a classification system of the techniques that comprise self-determination theory interventions, with satisfaction of psychological needs as an organizing principle. Candidate techniques were identified through a comprehensive review of self-determination theory interventions and nomination by experts. The study…
Negative emotional state slows down movement speed : behavioral and neural evidence
2019
Background Athletic performance is affected by emotional state. Athletes may underperform in competition due to poor emotion regulation. Movement speed plays an important role in many competition events. Flexible control of movement speed is critical for effective athletic performance. Although behavioral evidence showed that negative emotion can influence movement speed, the nature of the relationship remains controversial. Thus, the present study investigated how negative emotion affects movement speed and the neural mechanism underlying the interaction between emotion processing and movement control. Methods The present study combined electroencephalography (EEG) technology with a cued-…
Energy efficient resource allocation in heterogeneous software defined network: A reverse combinatorial auction approach
2015
In this paper, resource allocation for energy effi- ciency in heterogeneous Software Defined Network (SDN) with multiple network service providers (NSPs) is studied. The considered problem is modeled as a reverse combinatorial auction game, which takes different quality of service (QoS) requirements into account. The heterogeneous network selection associated with power allocation problem is optimized by maximizing the energy efficiency of data transmission. By exploiting the properties of fractional programming, the resulting non-convex Winner Determination Problem (WDP) is transformed into an equivalent subtractive convex optimization problem. The proposed reverse combinatorial auction ga…
Noise effect in a FitzHugh-Nagumo circuit driven by a bichromatic signal
2013
We analyze the response of a nonlinear circuit exactly ruled by the FitzHugh-Nagumo equations. This circuit is submitted to a bichromatic signal including a high frequency and a low frequency. In absence of noise, we show that for an appropriate amplitude of the high frequency driving, the response of the circuit estimated at the low frequency can be optimized via the phenomenon of vibrational resonance. Next, we show that under certain conditions, noise can contribute to the effect of vibrational resonance. Colored noise is also considered. Our experimental results are confirmed by a numerical analysis.
Experiencia con el uso de la resonancia magnética intraoperatoria de bajo campo en neurocirugía para el tratamiento de neoplasias cerebrales
2016
La evolución de la cirugía guiada por imágenes, constituye el ejemplo notorio del desarrollo mostrado por la Neurocirugía en las últimas décadas. Tras la introducción del microscopio quirúrgico a la cirugía, pocos han sido los avances tan rentables para la salud del paciente neuroquirúrgico en términos de grados de resección tumoral y morbilidad postquirúrgica. La neuronavegación solventó, en parte, los inconvenientes inherentes a la cirugía convencional y permitió la planificación de unas craneotomías más precisas minimizando las potenciales complicaciones de la cirugía. Sin embargo, los cambios en la anatomía producidos por el desplazamiento de las estructuras cerebrales al comunicarse el…
Transcranial Magnetic Stimulation and Neuroimaging Coregistration
2013
The development of neuroimaging techniques is one of the most impressive advancements in neuroscience. The main reason for the widespread use of these instruments lies in their capacity to provide an accurate description of neural activity during a cognitive process or during rest. This important advancement is related to the possibility to selectively detect changes of neuronal activity in space and time by means of different biological markers. Specifically, functional magnetic resonance imaging (fMRI), positron emission tomography (PET), single-photon emission computed tomography (SPECT), and nearinfrared spectroscopy (NIRS) use metabolic markers of ongoing neuronal activity to provide a…
Les thermes, le ski, et puis la nuit. Des stations illuminées à la valorisation des ressources environnementales nocturnes dans les territoires touri…
2015
International audience; Les réflexion engagées par le Collectif RENOIR interrogent le devenir des territoires touristiques au regard d’un processus émergent : la considération de la nuit et du paysage nocturne dans les projets de territoires. La mise en scène de ce que nous appelons des « ressources environnementales nocturnes » est appréhendée comme point de départ pour l’observation des stations touristiques en transition.Ce processus s’accompagne de mutations profondes, qui trouvent leurs sources dans la remise en cause d’un éclairage urbain (monumental, de voirie, de sécurisation, etc.) focalisé, jusque dans les années 1980, sur des aspects quantitatifs. Les différentes fonctions de l’é…