Search results for "Models"
showing 10 items of 8211 documents
A new method to "clean up" ultra high-frequency data
2007
In the applied econometrics, the availability of ultra high-frequency databases is having an important impact on the research market microstructure theory. The ultra high-frequency databases contain detailed reports of all the financial market activity information which is available. However, ultra high-frequency databases cannot be directly used. On one hand recording mistakes can be present, on the other hand missing information has to be inferred from the available data. In this paper, we propose a simple method in order to clean up the ultra high-frequency data from possible errors and we examine the method efficacy when we analyze data by using an autoregressive conditional duration (A…
Antioxidant betalains from cactus pear (Opuntia ficus-indica) inhibit endothelial ICAM-1 expression.
2004
It has been suggested that some pigments would have antioxidant properties and that their presence in dietary constituents would contribute to reduce the risk of oxidative stress–correlated diseases. Among others, inflammatory response depends on redox status and may implicate oxidative stress. Vascular endothelial cells are a direct target of oxidative stress in inflammation. We have tested the impact of the free radical scavenger and antioxidant properties of betalains from the prickle pear in an in vitro model of endothelial cells. Here we show the capacity of betalains to protect endothelium from cytokine- induced redox state alteration, through ICAM-1 inhibition. KEYWORDS: endothelial …
Apigenin‐induced nitric oxide production involves calcium‐activated potassium channels and is responsible for antiangiogenic effects
2007
Summary. Background: The dietary flavonoid apigenin (Api) has been demonstrated to exert multiple beneficial effects upon the vascular endothelium. The aim of this study was to examine whether Ca2+-activated K+ channels (KCa) are involved in endothelial nitric oxide (NO) production and antiangiogenic effects.Methods: Endothelial NO generation was monitored using a cyclic guanosine monophosphate radioimmunoassay. KCa activity and changes of the intracellular Ca2+ concentration [Ca2+]i were analyzed using the fluorescent dyes bis-barbituric acid oxonol, potassium-binding benzofuran isophthalate, and fluo-3. The endothelial angiogenic parameters measured were cell proliferation, [3H]-thymidine…
ERP denoising in multichannel EEG data using contrasts between signal and noise subspaces
2009
Abstract In this paper, a new method intended for ERP denoising in multichannel EEG data is discussed. The denoising is done by separating ERP/noise subspaces in multidimensional EEG data by a linear transformation and the following dimension reduction by ignoring noise components during inverse transformation. The separation matrix is found based on the assumption that ERP sources are deterministic for all repetitions of the same type of stimulus within the experiment, while the other noise sources do not obey the determinancy property. A detailed derivation of the technique is given together with the analysis of the results of its application to a real high-density EEG data set. The inter…
Developing Self-Awareness in Robots via Inner Speech
2019
The experience of inner speech is a common one. Such a dialogue accompanies the introspection of mental life and fulfills essential roles in human behavior, such as self-restructuring, self-regulation, and re-focusing on attentional resources. Although the underpinning of inner speech is mostly investigated in psychological and philosophical fields, the research in robotics generally does not address such a form of self-aware behavior. Existing models of inner speech inspire computational tools to provide a robot with this form of self-awareness. Here, the widespread psychological models of inner speech are reviewed, and a cognitive architecture for a robot implementing such a capability is…
Tethyan vs. Cordilleran ophiolites: a reappraisal of distintctive tectono-magmatic features of supra-subduction complexes in relation to the subducti…
2004
Abstract Supra-subduction zone (SSZ) ophiolites deserve special attention because they represent fundamental markers of intraoceanic convergence and generation of new lithosphere above subduction zones. Moreover, owing to their structural characteristics and location in the overriding plate, these complexes are far better represented and preserved than Mid-Ocean-Ridge-Basalt (MORB) ophiolites in orogenic belts. In terms of their structure, tectonics, and magmatic features, SSZ ophiolites may be classified in two main types: (1) “Tethyan complexes” (such as those of the Albanide-Hellenide belt), which mostly consist of complete and extensive volcanic, dyke, plutonic, and mantle sections with…
The Cth2 ARE-binding protein recruits the Dhh1 helicase to promote the decay of succinate dehydrogenase SDH4 mRNA in response to iron deficiency
2008
Iron is an essential nutrient that participates as a redox co-factor in a broad range of cellular processes. In response to iron deficiency, the budding yeast Saccharomyces cerevisiae induces the expression of the Cth1 and Cth2 mRNA-binding proteins to promote a genome-wide remodeling of cellular metabolism that contributes to the optimal utilization of iron. Cth1 and Cth2 proteins bind to specific AU-rich elements within the 3'-untranslated region of many mRNAs encoding proteins involved in iron-dependent pathways, thereby promoting their degradation. Here, we show that the DEAD box Dhh1 helicase plays a crucial role in the mechanism of Cth2-mediated mRNA turnover. Yeast two-hybrid experim…
Disentangling Housing Supply to Shift towards Smart Cities: Analysing Theoretical and Empirical Studies
2022
The search for a pleasant home has concerned people ever since. Paradoxically, people are facing strong difficulties in finding a decent place to settle their lives in cities. As such, the housing market regained momentum in connection with the development of Smart Cities, where life quality of residents is strongly emphasized. Well-being in the metropolis is affected by a wide variety of factors with housing supply being among the most important, hence stirred by financing costs, construction costs, vacancy rate, sales delay, inflation rate, housing stock, price of agricultural land, and regulation. The present article reviews empirical studies on housing supply for a better understanding …
On the emergence of the urban phenomenon. Part I
2001
In this paper we develop a relatively simple but general model describing the formation of urban agglomerations in a pre-industrial setting. Rural agglomeration on a local scale arises from the multiplication and specialization of intermediate goods and labor services, while dispersion is due to the commuting costs of agricultural workers. Urban agglomeration on a more global scale stems from the trade-off between increasing returns to scale and transport costs of goods. We derive a general equilibrium model of the formation of urban structures and show how population growth, strict indivisibilities and structural changes in the production sector can modify quantitatively and qualitatively …
Demographic change, new business formation and spatial concentration of population
2015
This paper investigates the role of urbanization in the relation between population change and new business formation. The hypothesis of research is that population change significantly influences new business formation only in regions at lower urbanization. This hypothesis is based on the idea that local demand and growing population are significant determinants of new business formation only for rural regions. Using Italian data, we find evidence in support of this hypothesis. Moreover, we find that evidence of spatial dependence in the relation between population change, new business formation and urbanization.