177,067 research outputs found
Testing axial symmetry and separability of lattice processes
No full textData collected on a rectangular lattice are common in many areas, and models used often make simplifying assumptions. These assumptions include axial symmetry in the spatial process and separability. Some di0erent methods for testing axial symmetry and separability are considered. Using the sample periodogram is shown to provide some simple satisfactory tests of both hypotheses, but tests for separability given axial symmetry have low power for small lattices
Model-based tests for simplification of lattice processes
No full textSeparable processes represent a convenient class of models for data collected on a regular rectangular lattice. Three model-based tests, for testing separability and testing axial symmetry and separability together, are presented. These are shown to be much more powerful than existing model-free tests using the sample periodogram, provided the model assumptions hold. A simulation study also suggests that these tests are not very sensitive to small departures from the assumed process
Testing for simplification in spatial models
No full textData collected on a rectangular lattice occur frequently in many areas such as field trials, geostatistics, remotely sensed data, and image analysis. Models for the spatial process often make simplifying assumptions, including axial symmetry and separability. We consider methods for testing these assumptions and compare tests based on sample covariances, tests based on the sample spectrum, and model-based tests
Size-Dependent Enforcement, Tax Evasion and Dimensional Trap
No full textSize-dependent tax enforcement is quite widespread worldwide, but the literature on its effects over firms’ behaviour is very scarce. By assuming different audit probabilities for small and large firms, we propose a dynamic model to study the consequences of size-dependent monitoring level on a firm’ fiscal compliance and its decision to invest and grow in a single-firm perspective. By combining analytical findings and simulation results, we show that: (1) under certain conditions, a dimensional trap may emerge, as
small firms have no advantage in growing and prefer to remain small to avoid stronger enforcement; (2) audit activity and fine levels are important tools available to the State to fight evasion, but a careful calibration is required not to incur undesired effects
The signaling power of CDS indexes
No full textThe focus of this work is to investigate the ability
of fluctuations in CDS indexes in predicting the outbreak of stock
market crises. The main goal is to show that CDS indexes may
provide investors and institutions with early warning signals of
financial distresses in the stock market. In this paper, we apply a
Markov switching model with states characterized by increasing
levels of volatility and compare the time in which the first switch
in a high volatility state occurs, respectively, in the CDS and in
the stock market index quotes
Industrial structure and evasion dynamics, is there any link?
No full textWe propose a model to describe the link between industrial structure and evasion dynamics in a heterogeneous setting, in which the monitoring efforts put in place by the State to fight evasion of firms depend on the market share of each firm. More precisely, while the convenience to evade taxes is determined as a Nash solution of an incomplete information game, a differentiated monitoring activity related to market concentration represents the original contribution of this work w.r.t. previous studies on the topic. As empirical evidence shows, high dimensional firms are more likely to be monitored, hence, when dynamics are considered, evasion and industrial structure evolution are strictly related. In fact, by combining analytical findings and simulation results, our work shows that: (1) firms with a sufficiently large market share, that is, larger than a certain dimensional threshold, comply with fiscal rules, thus confirming empirical evidence; (2) this dimensional threshold changes with the competition level between firms in a nonlinear way; (3) evasion affects the market structure, so that markets with high (low) competition tend to increase (decrease) their concentration over time; (4) evasion is affected by market structure and is minimum in moderately concentrated markets
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Stem cell therapy
No full textThe necessity of improving the health and quality of life of subjects affected by diverse injuries and chronic diseases, has led to develop a new branch of translational medicine, called Regenerative Medicine (RegMed). RegMed has the principal objects of restoring, maintaining or enhancing structures and functions of tissues and organs. In order to achieve these goals, the RegMed researchers have proposed and tested diverse approaches. The Stem Cell Therapy represents the central focus of RegMed, even if its applications may imply the onset of adverse conditions. Here, an overview of this topic will be reported, by pointing advantages and disadvantages
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
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