3,548 research outputs found
Measuring Euro Area Monetary Policy Transmission in a Structural Dynamic Factor Model
We study the effects of euro area common monetary policy by means of a structural dynamic factor model estimated on a large panel of euro area quarterly series. While we estimate a flat response of prices to a monetary policy shock, which we explain as aggregation of heterogeneous country-specific responses, we find no relevant asymmetries between countries in terms of output reaction. However, for both Spain and Italy, we find asymmetries in consumption, investment and unemployment. The introduction of the single currency in 1999 has helped reducing asymmetries in price responses but not in consumption and investment.
A multi-temporal phenology based classification approach for Crop Monitoring in Kenya
The SBAM (Satellite Based Agricultural Monitoring) project, funded by the Italian Space Agency aims at: developing a validated satellite imagery based method for estimating and updating the agricultural areas in the region of Central-Africa; implementing an automated process chain capable of providing periodical agricultural land cover maps of the area of interest and, possibly, an estimate of the crop yield. The project aims at filling the gap existing in the availability of high spatial resolution maps of the agricultural areas of Kenya. A high spatial resolution land cover map of Central-Eastern Africa including Kenya was compiled in the year 2000 in the framework of the Africover project using Landsat images acquired, mostly, in 1995. We investigated the use of phenological information in supporting the use of remotely sensed images for crop classification and monitoring based on Landsat 8 and, in the near future, Sentinel 2 imagery. Phenological information on crop condition was collected using time series of NDVI (Normalized Difference Vegetation Index) based on Landsat 8 images. Kenyan countryside is mainly characterized by a high number of fragmented small and medium size farmlands that dramatically increase the difficulty in classification; 30 m spatial resolution images are not enough for a proper classification of such areas. So, a pan-sharpening FIHS (Fast Intensity Hue Saturation) technique was implemented to increase image resolution from 30 m to 15 m. Ground test sites were selected, searching for agricultural vegetated areas from which phenological information was extracted. Therefore, the classification of agricultural areas is based on crop phenology, vegetation index behaviour retrieved from a time series of satellite images and on AEZ (Agro Ecological Zones) information made available by FAO (FAO, 1996) for the area of interest. This paper presents the results of the proposed classification procedure in comparison with land cover maps produced in the past years by other projects. The results refer to the Nakuru County and they were validated using field campaigns data. It showed a satisfactory overall accuracy of 92.66 % which is a significant improvement with respect to previous land cover maps
Ranking systemically important financial institutions
We propose a simple network–based methodology for ranking systemically important financial institutions. We view the risks of firms –including both the financial sector and the real economy– as a network with nodes representing the volatility shocks. The metric for the connections of the nodes is the correlation between these shocks. Daily dynamic centrality measures allow us to rank firms in terms of risk connectedness and firm characteristics. We present a general systemic risk index for the financial sector. Results from applying this approach to all firms in the S&P500 for 2003–2011 are twofold. First, Bank of America, JP Morgan and Wells Fargo are consistently in the top 10 throughout the sample. Citigroup and Lehman Brothers also were consistently in the top 10 up to late 2008. At the end of the sample, insurance firms emerge as systemic. Second, the systemic risk in the financial sector built–up from early 2005, peaked in September 2008, and greatly reduced after the introduction of TARP and the rescue of AIG. Anxiety about European debt markets saw the systemic risk begin to rise again from April 2010. We further decompose these results to find that the systemic risk of insurance and deposit–taking institutions differs importantly, the latter experienced a decline from late 2007, in line with the burst of the housing price bubble, while the former continued to climb up to the rescue of AIG
Surfing through the GFC : systemic risk in Australia
We provide empirical evidence on the degree of systemic risk in Australia before,
during and after the Global Financial Crisis. We calculate a daily index of systemic
risk from 2004 to 2013 in order to understand how real economy firms influence the
outcomes for the rest of the economy. This is done via a mapping of the interconnectedness
of the financial and non-financial sectors. The financial sector is in general the
home to the most consistently systemically risky firms in the economy. The mining
sector becomes occasionally as systemically risky as the financial sector, reflecting the
importance of understanding the interrelationships between the financial sector and
the real economy in monitoring systemic risks
Keeping it modern, making it sustainable. Monitoring and energy retrofitting the Urbino University Colleges
This paper presents a research to balance building conservation, users’ comfort and energy efficiency of a masterpiece of XX century architecture. The Urbino University Colleges were designed by architect Giancarlo de Carlo and built since 1962 to 1983 beside the Renaissance city. They host more than 1,000 students within 5 dormitories and 62,000 m2 surface. Authors discuss some outcomes from the “Keeping it modern” research program financed by the Getty Foundation in 2016, which aims at providing the Colleges with a sustainable conservation plan. The goal is to lower heating and operational costs to allow funds in conservation activities. Specific issues regard: the striking dimensions of the complex, the constructive features (brickwork walls, exposed concrete structures, single-glazed windows) and the lack of data about the hygrothermal performances.
The research thus includes a hygrothermal analysis, a proposal for the energy retrofitting, a building-HVAC model, a test on a pilot site. Authors have monitored surface temperatures, indoor air temperature and humidity for one year, even mapping their distribution through a digital psychrometer. Thermal imaging has been used to detect heat losses, thermal bridges and heat gains due to the solar radiation. Data have fed a building-HVAC model, which was a reference to design an appropriate strategy for retrofitting and improving the energy efficiency of the complex. Some solutions are being implemented on a pilot site. The building performances before and after retrofitting are compared.
Results provide indications to merge conservation and sustainability of a XX century heritage building.
In conclusion, the solid knowledge of each case confirms being required to support a retrofit proposal of a heritage building, moreover in case of a XX century building, as the cultural value of such a huge heritage is often disregarded to improve its energy performance
Gut Microbiome of an 11th Century A.D. Pre-Columbian Andean Mummy
The process of natural mummification is a rare and unique process from which little is known about the resulting microbial community structure. In the present study, we characterized the microbiome of paleofeces, and ascending, transverse and descending colon of an 11th century A.D. pre-Columbian Andean mummy by 16S rRNA gene high-throughput sequencing and metagenomics. Firmicutes were the most abundant bacterial group, with Clostridium spp. comprising up to 96.2% of the mummified gut, while Turicibacter spp. represented 89.2% of the bacteria identified in the paleofeces. Microbiome profile of the paleofeces was unique when compared to previously characterized coprolites that did not undergo natural mummification. We identified DNA sequences homologous to Clostridium botulinum, Trypanosoma cruzi and human papillomaviruses (HPVs). Unexpectedly, putative antibiotic-resistance genes including beta-lactamases, penicillin-binding proteins, resistance to fosfomycin, chloramphenicol, aminoglycosides, macrolides, sulfa, quinolones, tetracycline and vancomycin, and multi-drug transporters, were also identified. The presence of putative antibiotic-resistance genes suggests that resistance may not necessarily be associated with a selective pressure of antibiotics or contact with European cultures. Identification of pathogens and antibiotic-resistance genes in ancient human specimens will aid in the understanding of the evolution of pathogens as a way to treat and prevent diseases caused by bacteria, microbial eukaryotes and viruses
On Symmetries of Extremal Black Holes with One and Two Centers
After a brief introduction to the Attractor Mechanism, we review the
appearance of groups of type E7 as generalized electric-magnetic duality
symmetries in locally supersymmetric theories of gravity, with particular
emphasis on the symplectic structure of fluxes in the background of extremal
black hole solutions, with one or two centers. In the latter case, the role of
an "horizontal" symmetry SL(2,R) is elucidated by presenting a set of
two-centered relations governing the structure of two-centered invariant
polynomials.Comment: 1+13 pages, 2 Tables. Based on Lectures given by SF and AM at the
School "Black Objects in Supergravity" (BOSS 2011), INFN - LNF, Rome, Italy,
May 9-13 201
Role of calcium desensitization in the treatment of myocardial dysfunction after deep hypothermic circulatory arrest
Abstract
Introduction
Rewarming from deep hypothermic circulatory arrest (DHCA) produces calcium desensitization by troponin I (cTnI) phosphorylation which results in myocardial dysfunction. This study investigated the acute overall hemodynamic and metabolic effects of epinephrine and levosimendan, a calcium sensitizer, on myocardial function after rewarming from DHCA.
Methods
Forty male Wistar rats (400 to 500 g) underwent cardiopulmonary bypass (CPB) through central cannulation and were cooled to a core temperature of 13°C to 15°C within 30 minutes. After DHCA (20 minutes) and CPB-assisted rewarming (60 minutes) rats were randomly assigned to 60 minute intravenous infusion with levosimendan (0.2 μg/kg/min; n = 15), epinephrine (0.1 μg/kg/min; n = 15) or saline (control; n = 10). Systolic and diastolic functions were evaluated at different preloads with a conductance catheter.
Results
The slope of left ventricular end-systolic pressure volume relationship (Ees) and preload recruitable stroke work (PRSW) recovered significantly better with levosimendan compared to epinephrine (Ees: 85 ± 9% vs 51 ± 11%, P\u3c0.003 and PRSW: 78 ± 5% vs 48 ± 8%, P\u3c0.005; baseline: 100%). Levosimendan but not epinephrine reduced left ventricular stiffness shown by the end-diastolic pressure-volume relationship and improved ventricular relaxation (Tau). Levosimendan preserved ATP myocardial content as well as energy charge and reduced plasma lactate concentrations. In normothermia experiments epinephrine in contrast to Levosimendan increased cTnI phosphorylation 3.5-fold. After rewarming from DHCA, cTnI phosphorylation increased 4.5-fold in the saline and epinephrine group compared to normothermia but remained unchanged with levosimendan.
Conclusions
Levosimendan due to prevention of calcium desensitization by cTnI phosphorylation is more effective than epinephrine for treatment of myocardial dysfunction after rewarming from DHCA
Ion diffusion modelling of Fricke-agarose dosemeter gels
In Fricke-agarose gels, an accurate determination of the spatial dose distribution is hindered by the diffusion of ferric ions. In this work, a model was developed to describe the diffusion process within gel samples of finite length and, thus, permit the reconstruction of the initial spatial distribution of the ferric ions. The temporal evolution of the ion concentration as a function of the initial concentration is derived by solving Fick's second law of diffusion in two dimensions with boundary reflections. The model was applied to magnetic resonance imaging data acquired at high spatial resolution (0.3 mm) and was found to describe accurately the observed diffusion effect
First principles fluid modelling of magnetic island stabilization by ECCD
International audienceTearing modes are MHD instabilities that reduce the performances of fusion devices. They can however be controlled and suppressed using Electron Cyclotron Current Drive (ECCD) as demonstrated in various tokamaks. In this work, simulations of islands stabilization by ECCD-driven current have been carried out using the toroidal nonlinear 3D full MHD code XTOR-2F, in which a current-source term modeling the ECCD has been implemented. The efficiency parameter is computed and its variations with respect to source width and location are computed. The influence of parameters such as current intensity, source width and position with respect to the island is evaluated and compared to the Modified Rutherford Equation. We retrieve a good agreement between the simulations and the analytical predictions concerning the variations of control efficiency with source width and position. We also show that the 3D nature of the current source term can lead to the onset of an island if the source term is precisely applied on a rational surface. We report the observation of a flip phenomenon in which the O-and X-Points of the island rapidly switch their position in order for the island to take advantage of the current drive to grow
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