1,720,979 research outputs found
Evaluating the Influence of Motor Control on Selective Attention through a Stochastic Model: The Paradigm of Motor Control Dysfunction in Cerebellar Patient.
Full text linkAttention allows us to selectively process the vast amount of information with which we are confronted, prioritizing some aspects of information and ignoring others by focusing on a certain location or aspect of the visual scene. Selective attention is guided by two cognitive mechanisms: saliency of the image (bottom up) and endogenous mechanisms (top down). These two mechanisms interact to direct attention and plan eye movements; then, the movement profile is sent to the motor system, which must constantly update the command needed to produce the desired eye movement. A new approach is described here to study how the eye motor control could influence this selection mechanism in clinical behavior: two groups of patients (SCA2 and late onset cerebellar ataxia LOCA) with well-known problems of motor control were studied; patients performed a cognitively demanding task; the results were compared to a stochastic model based on Monte Carlo simulations and a group of healthy subjects. The analytical procedure evaluated some energy functions for understanding the process. The implemented model suggested that patients performed an optimal visual search, reducing intrinsic noise sources. Our findings theorize a strict correlation between the "optimal motor system" and the "optimal stimulus encoders.
Valutazione d’idoneità qualitativa di un ceppo di Oenococcus oeni da impiegare come starter della fermentazione malolattica in vino
No full textE' stato valutato un ceppo di Oenococcus oeni, PN4, per le sue capacità di condurre la fermentazione malolattica (FML) in vino, testando, le sue performances tecnologiche e qualitative sia in laboratorio sia in cantina. Nella sperimentazione è stato usato un ceppo commerciale, VP41, come riferimento. Il ceppo PN4 è risultato decarbossilasi negativo nel test qualitativo per la produzione di amine biogene quali istamina, tiramina e putrescina. Nel saggio per valutare le potenziali capacità di produrre carbammato di etile il ceppo sperimentale ha mostrato un limitato consumo di arginina (circa 20%). Inoltre, rispetto al ceppo di riferimento, il ceppo PN4 ha mostrato simile attività malolattica, ma maggiore attività beta-glucosidasica e proteasica. Con l'impiego del preparato liofilizzato ad inoculo diretto, è stata monitorata la FML in vino Soave. Il ceppo PN4 si è distinto per il rapido adattamento e altrettanto consumo di acido malico, terminando la fermentazione in 18 giorni. Nel vino il contenuto di amine biogene e di carbammato di etile è risultato trascurabile. Il ceppo PN4 ha metabolizzato maggiormente l'acido citrico producendo più diacetile e acido acetico del ceppo di riferimento. Il profilo sensoriale del vino fermento dal ceppo sperimentale è stato valuato, mediante panel test, positivamente, ma non si è distinto significativamente da quello del vino fermentato dal ceppo VP41
Comparison between simultaneous and sequential alcoholic and malolactic fermentations for partially dried grapes in the production of Amarone style wine
No full textWhen inducing malolactic fermentation (MLF) in wine, bacteria cells inoculated at the end or after alcoholic fermentation (AF), can find harsh conditions such as low pH, high ethanol and SO2, difficult to adapt to. To overcome this problem, bacteria inoculation in must or at the beginning of AF has been previously investigated. In this study, we compared MLF induced by bacteria inoculated in must of partially dried grapes (simultaneous yeast and bacteria inoculation or co-inoculation) with bacteria inoculated after AF, in wine characterized by pH 3.3 and 14.3% volume ethanol. In the yeast-bacterial co-inoculated trials, malic acid consumption was completed in 32 days, compared to 72 days in trials inoculated with bacteria after AF. In the trials not-inoculated with bacteria, the MLF totally failed. No additional increase of acetic acid and D-Lactic acid was observed in wines obtained with simultaneous AF/MLF compared to those produced by sequentially AF/MLF. Citric acid was not degraded in all trials. In our experimetal winemaking conditions yeast-bacterial co-inoculation resulted in a reduction of MLF time without having wine quality depreciation. This practice promises interesting results in the production of wines that are difficult to get through MLF
Evaluating the efficacy of lysozyme against lactic acid bacteria under different winemaking scenarios
No full textThis study evaluated the efficacy of lysozyme in winemaking to control lactic acid bacteria (LAB). In a winery vinification, indigenous LAB were partially and completely inhibited when lysozyme was added to red and white grape must respectively. This result was confirmed by using two selected strains of Lactobacillus brevis and Oenococcus oeni to contaminate the grape must. In the red wine microvinification, the cell population decreased only temporarily and malolactic fermentation terminated at different times, depending on the grape must pH and lysozyme dosage. In the white wine microvinification, cell mortality rates differed according to lysozyme dosage rather than pH values. During the fermentation, lysozyme activity was stable or decreased, depending on the absence or presence of grape must respectively. The study highlighted that lysozyme efficacy is strongly affected by the type of vinification
DEVICE FOR THE ANALYSIS OF THE CENTRAL NERVOUS SYSTEM BY APPLICATION OF A COMBINATION OF STIMULI AND THE STUDY OF CORRESPONDING REACTIONS
No full textGestire la malolattica con il coinoculo
No full textL'inoculo di batteri lattici al termine della fermentazione alcolica spesso da luogo a fermentazioni malolattiche lente o difficoltose. Il co-inoculo dei batteri assieme ai lieviti consente di superare queste difficoltà. Le prove sperimentali dimostrano che i tempi per la degradazione totale dell'acido malico sono assai più ridotti rispetto a quelli necessari con l'inoculo dei batteri a fine fermentazione alcolica
Using simplified trial macking test B to evacuate ongoing learning capabilities on visual search.
No full textEVA:Eye Tracking Stimulus Integrated Semi Automated Case Base System.
No full textIn a real world visual search is a common task depending from
sensory, perceptual and cognitive processes. Different classes
of eye movements are necessary to hold an image on the retina
during head rotation or movement of the image, and to move
the eye suddenly to a new point of interest in space. From a
functional point of view, two major classes of eye movements
are described in humans: those stabilizing gaze (optokinetic
nystagmus, oculovestibular reflex) and those moving gaze
(saccades, pursuits and vergence). Under natural conditions,
however, a mix of all kinds of eye movements permit
continuous scanning of the visual scene. The sequence of
fixations and saccades during visual exploration is an
expression of a number of cognitive processes; the use of
standardized tasks with pre-defined spatial-temporal variables
allows us to assess specific cognitive domains, such as
perception, attention, memory, preference and motivation.
Manipulating the search task can vary the demands on brain. In
turn, brain modulates visual search by selecting and limiting
the information available at various levels of processing.
The EVA software is a complete system based on a set of
stimulus and patient’s case able to stress brain functionalities in
order to assess some cognitive functions
Evaluating gaze control on a multi-target sequencing task: The distribution of fixations is evidence of exploration optimisation.
No full textMany high cognitive applications, such as vision processing and representation and understanding of images, often need to analyse in detail how an ongoing visual search was performed in a representative subset of the image, which may be arranged into sequences of loci, called regions of interest (ROIs). We used the Trial Making Test (TMT) in which subjects are asked to fixate a sequence of letters and numbers in a logical alphanumeric order. The main characteristic of TMT is to force the subject to perform a default and well-known path. The comparison of the expected scan-path with the observed scan-path provides a valuable method to investigate how a task force the subject to maintain a top-down internal representation of execution and how bottom-up influences the performance. We developed a mechanism that analyses the scan path using different algorithms, and we compared it with other methods: we found that fixations outside the ROI are direct influence of exploration strategy. The paper discusses the method in healthy subjects
Indagini microbiologiche sull’efficacia del lisozima nella vinificazione in rosso.
No full textLo studio valuta l’efficacia del lisozima, aggiunto nel mosto, come agenteantimicrobico nella produzione di vino rosso attraverso prove di laboratorio e dicantina. La variabilità della sensibilità al lisozima nelle varie specie di batterilattici e l’interazione con i polifenoli, rilasciati durante la macerazione delle vinacce,condizionano fortemente la sua capacità di controllo delle contaminazionipre-fermentative. Si discute sull’opportunità del suo utilizzo nella vinificazione in rosso
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