15,171 research outputs found

    From old wars to new wars and global terrorism

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    Even before 9/11 there were claims that the nature of war had changed fundamentally. The 9/11 attacks created an urgent need to understand contemporary wars and their relationship to older conventional and terrorist wars, both of which exhibit remarkable regularities. The frequency-intensity distribution of fatalities in "old wars", 1816-1980, is a power-law with exponent 1.80. Global terrorist attacks, 1968-present, also follow a power-law with exponent 1.71 for G7 countries and 2.5 for non-G7 countries. Here we analyze two ongoing, high-profile wars on opposite sides of the globe - Colombia and Iraq. Our analysis uses our own unique dataset for killings and injuries in Colombia, plus publicly available data for civilians killed in Iraq. We show strong evidence for power-law behavior within each war. Despite substantial differences in contexts and data coverage, the power-law coefficients for both wars are tending toward 2.5, which is a value characteristic of non-G7 terrorism as opposed to old wars. We propose a plausible yet analytically-solvable model of modern insurgent warfare, which can explain these observations.Comment: For more information, please contact [email protected] or [email protected]

    A Survey of the Reef-Related Medusa (Cnidaria) Community in the Western Caribbean Sea

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    The species composition, distribution, and abundance of medusae collected during a 4-day plankton survey in a reef system of the Mexican Caribbean were studied. Highest mean medusae abundance was observed over the fore-reef zone and in daytime samples. Lowest abundances occurred in the reef lagoon and at dusk. Seventeen species were identified, with Liriope tetraphylla, Aglaura hemistoma, Cubaia aphrodite, and Sarsia prolifera being the most abundant. They belong to a group of medusae dominant along the world\u27s second largest barrier reef. Cluster analysis revealed primary (fore-reef) and secondary (reef lagoon, channel) oceanic groups, showing the strong oceanic influence along and across the reef system. Day-to-day variation in the reef medusan community seemed relatively unimportant. The community structure of the reef medusa fauna appeared to be quite uniform despite the expected migratory behavior of these predators, tidal exchange across the reef, introduction of oceanic species, and time of day. The species composition was most closely related to that of the Campeche Bank and oceanic Caribbean waters. Dominance of oceanic medusae within the reef lagoon was attributed to the narrowness of the continental shelf and the mesoscale hydrological features of the zone

    A Survey of the Reef-Related Medusa (Cnidaria) Community in the Western Caribbean Sea

    Get PDF
    The species composition, distribution, and abundance of medusae collected during a 4-day plankton survey in a reef system of the Mexican Caribbean were studied. Highest mean medusae abundance was observed over the fore-reef zone and in daytime samples. Lowest abundances occurred in the reef lagoon and at dusk. Seventeen species were identified, with Liriope tetraphylla, Aglaura hemistoma, Cubaia aphrodite, and Sarsia prolifera being the most abundant. They belong to a group of medusae dominant along the world\u27s second largest barrier reef. Cluster analysis revealed primary (fore-reef) and secondary (reef lagoon, channel) oceanic groups, showing the strong oceanic influence along and across the reef system. Day-to-day variation in the reef medusan community seemed relatively unimportant. The community structure of the reef medusa fauna appeared to be quite uniform despite the expected migratory behavior of these predators, tidal exchange across the reef, introduction of oceanic species, and time of day. The species composition was most closely related to that of the Campeche Bank and oceanic Caribbean waters. Dominance of oceanic medusae within the reef lagoon was attributed to the narrowness of the continental shelf and the mesoscale hydrological features of the zone

    Susceptibility of clinical isolates of bacteria to cefamandole, cefoxitin and cephalothin

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    The in vitro susceptibility was determined of 274 isolates to cephalothin and two new antibiotics, cefamandole and cefoxitin. Cefamandole was comparable to cephalothin in preventing growth of cultures of the gram positive organisms except for penicillin-resistant Staphylococcus aureus which was more sensitive to cephalothin. Cefamandole was more active than cephalothin against all the gram negative bacteria including Haemophilus influenzae and in addition it was active against many strains of Enterobacter sp. Cefoxitin was less active than cephalothin against the gram positive organisms but it was more active against most of the gram negative bacteria. In addition. It was active against Serratia and indole positive Proteus which are uniformly resistant to cephalothin

    Spectroscopic Survey of {\gamma} Doradus Stars I. Comprehensive atmospheric parameters and abundance analysis of {\gamma} Doradus stars

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    We present a spectroscopic survey of known and candidate γ\gamma\,Doradus stars. The high-resolution, high signal-to-noise spectra of 52 objects were collected by five different spectrographs. The spectral classification, atmospheric parameters (\teff, logg\log g, ξ\xi), vsiniv\sin i and chemical composition of the stars were derived. The stellar spectral and luminosity classes were found between G0-A7 and IV-V, respectively. The initial values for \teff\ and \logg\ were determined from the photometric indices and spectral energy distribution. Those parameters were improved by the analysis of hydrogen lines. The final values of \teff, \logg\ and ξ\xi were derived from the iron lines analysis. The \teff\ values were found between 6000\,K and 7900\,K, while \logg\,values range from 3.8 to 4.5\,dex. Chemical abundances and vsiniv\sin i values were derived by the spectrum synthesis method. The vsiniv\sin i values were found between 5 and 240\,km\,s1^{-1}. The chemical abundance pattern of γ\gamma\,Doradus stars were compared with the pattern of non-pulsating stars. It turned out that there is no significant difference in abundance patterns between these two groups. Additionally, the relations between the atmospheric parameters and the pulsation quantities were checked. A strong correlation between the vsiniv\sin i and the pulsation periods of γ\gamma\,Doradus variables was obtained. The accurate positions of the analysed stars in the H-R diagram have been shown. Most of our objects are located inside or close to the blue edge of the theoretical instability strip of γ\gamma\,Doradus.Comment: 18 pages, 13 figure

    Beating patterns of filaments in viscoelastic fluids

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    Many swimming microorganisms, such as bacteria and sperm, use flexible flagella to move through viscoelastic media in their natural environments. In this paper we address the effects a viscoelastic fluid has on the motion and beating patterns of elastic filaments. We treat both a passive filament which is actuated at one end, and an active filament with bending forces arising from internal motors distributed along its length. We describe how viscoelasticity modifies the hydrodynamic forces exerted on the filaments, and how these modified forces affect the beating patterns. We show how high viscosity of purely viscous or viscoelastic solutions can lead to the experimentally observed beating patterns of sperm flagella, in which motion is concentrated at the distal end of the flagella

    Participatory Situational Analysis: How can policy and regulation support resource recovery? Synthesis workshop report

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    The results presented in this report arise from four workshops that took place throughout the UK in Northern Ireland, Scotland, Wales and England. Using a ‘participatory situational analysis approach each workshop strived to answer the question: “If we wanted to realise resource recovery in the UK, how would it be possible within our policy and regulatory context?” Stakeholders attending the workshops ranged from academia, government, industry and the NGO WRAP. This report captures their insights into the diverse legislative areas that need to be integrated and aligned when aiming for a more circular economy, the ways in which policy and regulation enable this, and which particular actors need to be involved and the actions they should take. Taking the results into account, an action plan with seven key elements was recommended. This report is the outcome of the RRfW mini-project ‘Participatory situational analysis for the implementation of RRfW technologies and vision‘
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