2,144 research outputs found

    Growth, History, or Institutions? What Explains State Fragilityin Sub-Saharan Africa

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    We explore the determinants of state fragility in sub-Saharan Africa. Controlling for a wide range of economic, demographic, geographic and istitutional regressors, we find that institutions, and in particular the civil liberties index and the number of revolutions, are the main determinants of fragility, even taking into account their potential endogeneity. Economic factors such as income growth and investment display a non robust impact after controlling for omitted variables and reverse causality. Colonial variables reflecting the history of the region display a marginal impact on fragility once institutions are accounted for

    The Fragile Definition of State Fragility

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    We investigates the link between fragility and economic development in sub-Saharan Africa over a yearly panel including 28 countries for the 1999-2004 period. Beside the conventional definition of fragility adopted by the OECD Development Assistance Committee, we introduce the more severe definition of extreme fragility. We show that only the latter exerts a significantly negative impact on economic development, once standard economic, demographic, and institutional regressors are accounted for. As a by-product of this investigation we produce up-to-date evidence on the growth performance of the area. We find a tendency to convergence and no influence of geographic and historical factors

    Novel Deterministic Detection and Estimation Algorithms for Colocated Multiple-Input Multiple-Output Radars

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    In this manuscript, the problem of detecting multiple targets and estimating their spatial coordinates (namely, their range and the direction of arrival of their electromagnetic echoes) in a colocated multiple-input multiple-output radar system operating in a static or slowly changing two-dimensional or three-dimensional propagation scenario is investigated. Various solutions, collectively called range & angle serial cancellation algorithms, are developed for both frequency modulated continuous wave radars and stepped frequency continuous wave radars. Moreover, specific technical problems experienced in their implementation are discussed. Finally, the accuracy achieved by these algorithms in the presence of multiple targets is assessed on the basis of both synthetically generated data and of the measurements acquired through three different multiple-input multiple-output radars and is compared with that provided by other methods based on multidimensional Fourier analysis and multiple signal classification

    Longitudinal study of Salmonella infection in four Italian farrow-to finish swine herds

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    A longitudinal study of Salmonella enterica infection was carried out in 4 Italian farrow-to-finish swine herds. In each herd 5 litters were randomly selected and in each litter 6 piglets ear tagged. Thus, on each farm 30 pigs were included in the study. Individual blood samples were collected for serologic examination at weaning from all piglets and in the same day from all sows 1n the farrowing unit. Piglets were bled again at approximately 60, 90, 150, 210 and 270 days of life with the last blood sample collected at slaughtering. In one herd, in which the duration of productive cycle was about 12 months, the last blood samples was collected at 350 days of life. 5 pen pooled faecal samples were collected from each herd for bacteriological examination with the same time schedule of blood samples. At slaughtering mesenteric lymph nodes were collected from each ear tagged pig. Sera-prevalence (cutoff S/P ratio 0,25) in sows varied from 93,8% to 100%. In all herds sera-prevalence in piglets showed a similar profile with complete decline of maternal antibodies at day 60 and clear sera-conversion between day 90 and day 150. The peak of sera-prevalence was observed between day 210 and day 270. Sera-prevalence at slaughtering varied from 66% to 100%. Salmonella was isolated from faecal samples in 3 out of 4 herds. No Salmonella was isolated from mesenteric lymph nodes at slaughter in 2 herds. Culture prevalence from mesenteric lymph nodes in the other herds was respectively 3,3% and 30%. This longitudinal study provides original information about epidemiological dynamics of Salmonella enterica infection in Italian swine herds in consideration of the typical longer fattening cycles

    Secondary spontaneous pneumothorax and bullous lung disease in cannabis and tobacco smokers. A case-control study.

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    Background The notion that smoking cannabis may damage the respiratory tract has been introduced in recent years but there is still a paucity of studies on this subject. The aim of this study was to investigate the relationship between cannabis smoking, pneumothorax and bullous lung disease in a population of operated patients. Methods and findings We performed a retrospective study on patients operated on for spontaneous pneumothorax. Patients were divided into three groups according to their smoking habit: cannabis smokers, only-tobacco smokers and nonsmokers. Cannabis lifetime exposure was expressed in dose-years (1d/y = 1 gram of cannabis/week for one year). Clinical, radiological and perioperative variables were collected. The variables were analyzed to find associations with smoking habit. The impact of the amount of cannabis consumption was also investigated by ROC curves analysis. Of 112 patients, 39 smoked cannabis, 23 smoked only tobacco and 50 were nonsmokers. Median cannabis consumption was 28 dose/years, median tobacco consumption was 6 pack/years. Cannabis smokers presented with more severe chronic respiratory symptoms and bullous lung disease and with a higher incidence of tension pneumothorax than both tobacco smokers and nonsmokers. Cannabis smokers also developed a larger pneumothorax, experienced prolonged postoperative stay and demonstrated a higher incidence of pneumothorax recurrence after the operation than nonsmokers did. The risk of occurrence of chronic respiratory symptoms and bullous lung disease in cannabis smokers was dose-related. Conclusions Cannabis smoking seems to increase the risk of suffering from respiratory complaints and can have detrimental effects on lung parenchyma, in a dose-dependent manner. Cannabis smoking also negatively affected the outcome of patients operated for spontaneous pneumothorax. A history of cannabis abuse should always be taken in patients with pneumothorax. There may be need for a specific treatment for pneumothorax in cannabis smokers

    Geochemistry of natural and anthropogenic fall-out (aerosol and precipitation) collected in NW Mediterranean: two different multivariate statistical approaches

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    The chemical characteristics of the mineral fractions of aerosol and precipitation collected in Sardinia (NW Mediterranean) are highlighted by means of two multivariate statistical approaches. Two different combinations of classification and statistical methods for geochemical data are presented. It is shown that the application of cluster analysis subsequent to Q-Factor analysis better distinguishes among Saharan dust, Background pollution (Europe-Mediterranean) and Local aerosol from various source regions (Sardinia). Conversely, the application of simple cluster analysis was able to distinguish only between aerosols and precipitation particles, without assigning the sources (local or distant) to the aerosol. This method also highlighted the fact that crust-enriched precipitation is similar to desert-derived aerosol. Major elements (Al, Na) and trace metal (Pb) turn out to be the most discriminating elements of the analysed data set. Independent use of mineralogical, granulometric and meteorological data confirmed the results derived from the statistical methods employed

    Measurement of atmospheric deposition of polychlorinated dibenzo-p- dioxin and dibenzofurans in the Lagoon of Venice, Italy.

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    Data on atmospheric fall-out of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) were provided by collecting bulk deposition in four stations inside the Lagoon of Venice. A total of 44 monthly samples was collected during the period July 1998–July 1999 in one site near an industrial area (Porto Marghera), one site in the city of Venice, and two sites in the southern- and northernmost ends of the Lagoon. Fluxes of PCDD/Fs were between 0.1 and 470 pg m-2 d-1 , corresponding to 0–9.2 pg of 2,3,7,8-TCDD equivalents (TEQ) m-2 d-1 , with a gradient increasing from remote to urban/industrial stations. Thus, annual deposition of PCDD/Fs to the Lagoon (total area ¼ 550 km 2 ), calculated with various methods, turned out to be ~12 g, corresponding to ~400 mg TEQ. Significant differences were found among the stations, with a clear fingerprinting signature (PCDF/PCDD > 1) of the deposition collected near Porto Marghera, and a reversed pattern (PCDF/PCDD < 1) in the rest of the Lagoon, which pattern was similar to the sediments collected in the same locations. Lastly, the amount of bulk PTEQ of all stations was compared with the guide values for dioxins in depositions proposed by De Fré et al. [Organohalogen Compounds 45 (2000) 324]

    Recent advances in asymmetric catalysis using p‐block elements

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    The development of new methods for enantioselective reactions that generate stereogenic centres within molecules are a cornerstone of organic synthesis. Typically, metal catalysts bearing chiral ligands as well as chiral organocatalysts have been employed for the enantioselective synthesis of organic compounds. In this review, we highlight the recent advances in main group catalysis for enantioselective reactions using the p‐block elements (boron, aluminium, phosphorus, bismuth) as a complementary and sustainable approach to generate chiral molecules. Several of these catalysts benefit in terms of high abundance, low toxicity, high selectivity, and excellent reactivity. This minireview summarises the utilisation of chiral p‐block element catalysts for asymmetric reactions to generate value‐added compounds

    Toxicity assessment of atmospheric fall-out at Venice.

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    Data on atmospheric fall-out of dioxins and furans (PCDD-Fs), dioxin-like polychlorobyphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs) and hexachlorobenzene (HCB) were provided by collecting bulk depositions in four stations inside the Lagoon of Venice. A total of 44 monthly samples was collected in one site near an industrial area, one site in the city of Venice, and two sites in the southern and northern ends of the Lagoon
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