2,783 research outputs found

    A multi-temporal phenology based classification approach for Crop Monitoring in Kenya

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    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

    Measuring Euro Area Monetary Policy Transmission in a Structural Dynamic Factor Model

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    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.

    Testing Nowcast Monotonicity with Estimated Factors

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    This article proposes a test to determine whether “big data” nowcasting methods, which have become an important tool to many public and private institutions, are monotonically improving as new information becomes available. The test is the first to formalize existing evaluation procedures from the nowcasting literature. We place particular emphasis on models involving estimated factors, since factor-based methods are a leading case in the high-dimensional empirical nowcasting literature, although our test is still applicable to small-dimensional set-ups like bridge equations and MIDAS models. Our approach extends a recent methodology for testing many moment inequalities to the case of nowcast monotonicity testing, which allows the number of inequalities to grow with the sample size. We provide results showing the conditions under which both parameter estimation error and factor estimation error can be accommodated in this high-dimensional setting when using the pseudo out-of-sample approach. The finite sample performance of our test is illustrated using a wide range of Monte Carlo simulations, and we conclude with an empirical application of nowcasting U.S. real gross domestic product (GDP) growth and five GDP sub-components. Our test results confirm monotonicity for all but one sub-component (government spending), suggesting that the factor-augmented model may be misspecified for this GDP constituent. Supplementary materials for this article are available online

    Surfing through the GFC : systemic risk in Australia

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    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

    Reduction of multidrug-resistant (Mdr) bacterial infections during the covid-19 pandemic: a retrospective study

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    Multidrug-resistant (MDR) organisms are emerging as some of the main healthcare prob-lems worldwide. During the COVID-19 pandemic, several Infection Prevention and Control (IPC) measures have been adopted to reduce nosocomial microorganism transmission. We performed a case–control study to identify if the incidence of MDR bacterial infections while using pandemic-related preventive measures is lower than in previous years. From 2017 to 2020, we monitored hospital discharges over a four-month period (P #) (1 March to 30 June) in St. Andrea Hospital, Rome. In total, we reported 1617 discharges. Pearson’s chi-squared test was used to identify significant differences. A value of p ≤ 0.05 was considered statistically significant. A significant reduction in the incidence of total MDR bacterial infections was observed during the pandemic compared to in prepandemic years (p < 0.05). We also found a significantly higher incidence of MDR bacterial infections in COVID-19 departments compared with other medical departments (29% and 19%, respectively), with extended-spectrum β-lactamase Klebsiella pneumoniae as the pathogens presenting the highest increase. This study demonstrates that maintaining a high level of preventive measures could help tackle an important health problem such as that of the spread of MDR bacteria

    Criteria for the Evaluation of Italian Scientific Institutes for Research, Hospitalization and Healthcare (IRCCS): Comparison with European Standards and Certification Models

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    The definition of the title 'Istituto di Ricovero e Cura a Carattere Scientifico' (IRCCS) and how this title is given by the Italian Ministry of Health is presented. Specifically, the first assessment of a commission concerning the essential information for the accreditation process is introduced. Moreover, the two years review process that aims to collect last updated information of the IRCCS, to identify level of excellence and critical aspects, is also explained. The present Italian forms and international manuals like Joint Commission, OECI and HCERES were schematized using UML diagrams. The current IRCCS accreditation forms are presented with the suggested updates organized in some levels of structuring. We compared the Italian forms with the manuals required to obtain international certifications (Joint Commission and OECI) and we analyzed the criteria for the evaluation of research units in France (the HCERES standards). Although it is a preliminary study, the use of UML diagrams allows to schematize a new accreditation model, in line with European guidelines and the most important international certifications
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