2,345 research outputs found
Business Cycles, Core and Periphery in Monetary Unions: Comparing Europe and North America
We compare Europe with the USA and Canada as regards business cycle synchronization and core-periphery patterns. A long sample (1950-2005) makes it possible to study how these aspects have evolved over time. Results support the economic viability of EMU. Average cyclical correlations among European countries have risen significantly, reaching levels close to, or even higher than, those of North American regions. Applying fuzzy clustering to the analysis of core-periphery issues, we find Europe to actually outperform North America: the core-periphery divide is milder, and peripheral status seems generally less protracted.European Union, Canada, United States, Monetary Unions, Business Cycles, Fuzzy Clustering.
Measuring the vulnerability of the Uruguayan population to vector-borne diseases via spatially hierarchical factor models
We propose a model-based vulnerability index of the population from Uruguay
to vector-borne diseases. We have available measurements of a set of variables
in the census tract level of the 19 Departmental capitals of Uruguay. In
particular, we propose an index that combines different sources of information
via a set of micro-environmental indicators and geographical location in the
country. Our index is based on a new class of spatially hierarchical factor
models that explicitly account for the different levels of hierarchy in the
country, such as census tracts within the city level, and cities in the country
level. We compare our approach with that obtained when data are aggregated in
the city level. We show that our proposal outperforms current and standard
approaches, which fail to properly account for discrepancies in the region
sizes, for example, number of census tracts. We also show that data aggregation
can seriously affect the estimation of the cities vulnerability rankings under
benchmark models.Comment: Published in at http://dx.doi.org/10.1214/11-AOAS497 the Annals of
Applied Statistics (http://www.imstat.org/aoas/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Fractional dynamics and MDS visualization of earthquake phenomena
This paper analyses earthquake data in the perspective of dynamical systems and fractional calculus (FC). This new standpoint uses Multidimensional Scaling (MDS) as a powerful clustering and visualization tool. FC extends the concepts of integrals and derivatives to non-integer and complex orders. MDS is a technique that produces spatial or geometric representations of complex objects, such that those objects that are perceived to be similar in some sense are placed on the MDS maps forming clusters. In this study, over three million seismic occurrences, covering the period from January 1, 1904 up to March 14, 2012 are analysed. The events are characterized by their magnitude and spatiotemporal distributions and are divided into fifty groups, according to the Flinn–Engdahl (F–E) seismic regions
of Earth. Several correlation indices are proposed to quantify the similarities among
regions. MDS maps are proven as an intuitive and useful visual representation of the complex relationships that are present among seismic events, which may not be perceived on
traditional geographic maps. Therefore, MDS constitutes a valid alternative to classic visualization tools for understanding the global behaviour of earthquakes
Evaluating the Neolithic expansion at both shores of the Mediterranean Sea
During the Neolithic, human populations underwent cultural and technological developments that led to an agricultural revolution. Although the population genetics and evolution of European Neolithic populations have been extensively studied, little is known regarding the Neolithic expansion in North Africa with respect to Europe. One could expect that the different environmental and geological conditions at both shores of the Mediterranean Sea could have led to contrasting expansions. In order to test this hypothesis, we compared the Neolithic expansion in Europe and North Africa accounting for possible migration between them through the Strait of Gibraltar. We analyzed the entire X chromosome of 580 individuals from 20 populations spatially distributed along the North of Africa and Europe. Next, we applied approximate Bayesian computation based on extensive spatially explicit computer simulations to select among alternative scenarios of migration through the Strait of Gibraltar and to estimate population genetics parameters in both expansions. Our results suggest that, despite being more technologically advanced, Neolithic populations did not expand faster than Paleolithic populations, which could be interpreted as a consequence of a more sedentary lifestyle. We detected reciprocal Neolithic migration between the Iberian Peninsula and North Africa through the Strait of Gibraltar. Counterintuitively, we found that the studied Neolithic expansions presented similar levels of carrying capacity and migration, and occurred at comparable speeds, suggesting a similar demic process of substitution of hunter–gatherer populations. Altogether, the Neolithic expansion through both Mediterranean shores was not so different, perhaps because these populations shared similar technical abilities and lifestyle patterns.Fundação para a Ciência e a Tecnologia | Ref. POCI-01-0145-FEDER-007274Fundação para a Ciência e a Tecnologia | Ref. SFRH/BD/97200/2013Fundação para a Ciência e a Tecnologia | Ref. IF/01262/2014Fundação para a Ciência e a Tecnologia | Ref. IF/00955/2014Ministerio de Economía y Competitividad | Ref. RYC-2015-18241Ministerio de Economía y Competitividad | Ref. CGL2013-44351-
Empirical Laws and Foreseeing the Future of Technological Progress
The Moore’s law (ML) is one of many empirical expressions that is used to characterize
natural and artificial phenomena. The ML addresses technological progress and is expected to
predict future trends. Yet, the “art” of predicting is often confused with the accurate fitting of
trendlines to past events. Presently, data-series of multiple sources are available for scientific
and computational processing. The data can be described by means of mathematical expressions
that, in some cases, follow simple expressions and empirical laws. However, the extrapolation
toward the future is considered with skepticism by the scientific community, particularly in the
case of phenomena involving complex behavior. This paper addresses these issues in the light of
entropy and pseudo-state space. The statistical and dynamical techniques lead to a more assertive
perspective on the adoption of a given candidate law.info:eu-repo/semantics/publishedVersio
The sol-gel entrapment of noble metals in hybrid silicas: a molecular insight
BACKGROUND: Why are metal nanoparticles sol-gel entrapped in ORMOSIL so active and stable? In other words, why ORMOSIL-entrapped metal nanoparticles are more active and selective than many heterogenized counterparts, including silica-entrapped noble metals? RESULTS: Unveiling specific interactions between MNPs and the molecular structure of ORMOSIL, this work investigates subtle structural aspects through DRIFT spectroscopy. CONCLUSIONS: The results point to interactions between entrapped Pd and Pt nanocrystallites with the organosilica sol-gel cages similar to those taking place in enzymes
Avaliação não invasiva da pressão venosa central por ecocardiografia em cuidados intensivos : particularidades nos doentes com dilatação do ventrículo direito e exacerbação de doença pulmonar crónica
Copyright © 2006 Sociedade Portuguesa de Pneumologia/SPP. Published by Elsevier España, S.L.Objectives: To determine the possibility of non-invasive estimation of central venous pressure (CVP) through inferior vena cava (IVC) analysis, using transthoracic echocardiography (TTE). Design: A prospective 3-year study. Setting: A 16-bed medical/surgical Intensive Care Unit (ICU). Methods: Patients admitted to the ICU were enrolled. CVP measurement and TTE (determining cardiac chambers dimension and left ventricular shortening fraction) with IVC analysis (maximum dimension and IVC index) were performed simultaneously. Parametric and non-parametric statistical analysis was performed to establish correlations between variables. Results: 560 patients were admitted to the study, including 477 in whom IVC was analysed, aging 62.2 ± 17.3 years, a mean ICU stay 11.9 ± 18.7 days, a APACHE II score 23.9 ± 8.9 and a SAPS II score 55.7 ± 20.4. Through linear regression analysis CVP was influenced by IVC index (p=0.001), IVC maximum dimension (p=0.013) and presence of mechanical ventilation (p=0.002). A statistically significant correlation was found between the following parameters: an IVC index13mmHg; an IVC index and a CVP 26%-50%; an IVC index >51% and CVP 20mm and a CVP >13mmHg; an IVC maximum dimension 7mmHg was observed, and in patients with chronic respiratory failure (who presented a high prevalence of right ventricular enlargement) a lack of agreement between IVC index >50% and CVP 13mmHg; índice da VCI entre 26 e 50% e PVC entre 8 e 12mmHg; índice da VCI> 51% e PVC> 7mmHg; dimensão máxima da VCI> 20mmHg e PVC> 13 mmHg; dimensão máxima da VCI> 10mm e PVC> 7mmHg. Nos doentes com dilatação do ventrículo direito (VD) observou-se uma relação mais fraca entre a PVC 50%. A dimensão máxima da VCI, mas não o seu índice, correlacionou-se com a dilatação do VD e AD. Conclusões: A análise da VCI por ETT revelou-se útil na avaliação qualitativa da PVC em doentes admitidos numa UCIP. Em doentes com dilatação do VD e admitidos por exacerbação de doença pulmonar crónica, os métodos avaliados não foram fidedignos para valores baixos de PVC. A dilatação da VCI traduz melhor a cronicidade da doença, enquanto o índice da VCI reflecte melhor o estado de volemia.info:eu-repo/semantics/publishedVersio
Spatially explicit analysis reveals complex human genetic gradients in the Iberian Peninsula
The Iberian Peninsula is a well-delimited geographic region with a rich and complex human history. However, the causes of its genetic structure and past migratory dynamics are not yet fully understood. In order to shed light on them, here we evaluated the gene flow and genetic structure throughout the Iberian Peninsula with spatially explicit modelling applied to a georeferenced genetic dataset composed of genome-wide SNPs from 746 individuals belonging to 17 different regions of the Peninsula. We found contrasting patterns of genetic structure throughout Iberia. In particular, we identified strong patterns of genetic differentiation caused by relevant barriers to gene flow in northern regions and, on the other hand, a large genetic similarity in central and southern regions. In addition, our results showed a preferential north to south migratory dynamics and suggest a sex-biased dispersal in Mediterranean and southern regions. The estimated genetic patterns did not fit with the geographical relief of the Iberian landscape and they rather seem to follow political and linguistic territorial boundaries.Fundação para a Ciência e a Tecnologia | Ref. POCI-01-0145-FEDER-007274Fundação para a Ciência e a Tecnologia | Ref. SFRH/BD/97200/2013Fundação para a Ciência e a Tecnologia | Ref. IF/01262/2014Ministerio de Economía | Ref. RYC-2015-18241Ministerio de Economía | Ref. MDM-2014-0370Ministerio de Economía y Competitividad | Ref. CGL2016-75389-
CD117 immunoexpression in canine mast cell tumours: correlations with pathological variables and proliferation markers
<p>Abstract</p> <p>Background</p> <p>Cutaneous mast cell tumours are one of the most common neoplasms in dogs and show a highly variable biologic behaviour. Several prognosis tools have been proposed for canine mast cell tumours, including histological grading and cell proliferation markers. CD117 is a receptor tyrosine kinase thought to play a key role in human and canine mast cell neoplasms. Normal (membrane-associated) and aberrant (cytoplasmic, focal or diffuse) CD117 immunoexpression patterns have been identified in canine mast cell tumours. Cytoplasmic CD117 expression has been found to correlate with higher histological grade and with a worsened post-surgical prognosis. This study addresses the role of CD117 in canine mast cell tumours by studying the correlations between CD117 immunoexpression patterns, two proliferation markers (Ki67 and AgNORs) histological grade, and several other pathological variables.</p> <p>Results</p> <p>Highly significant (p < 0,001) correlations were found between CD117 immunostaining patterns and histological grade, cell proliferation markers (Ki67, AgNORs) and tumoral necrosis. Highly significant (p < 0,001) correlations were also established between the two cellular proliferation markers and histological grade, tumour necrosis and epidermal ulceration. A significant correlation (p = 0.035) was observed between CD117 expression patterns and epidermal ulceration. No differences were observed between focal and diffuse cytoplasmic CD117 staining patterns concerning any of the variables studied.</p> <p>Conclusion</p> <p>These findings highlight the key role of CD117 in the biopathology of canine MCTs and confirm the relationship between aberrant CD117 expression and increased cell proliferation and higher histological grade. Further studies are needed to unravel the cellular mechanisms underlying focal and diffuse cytoplasmic CD117 staining patterns, and their respective biopathologic relevance.</p
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