371 research outputs found
Seasonal variations in monoterpene profiles and ecophysiological traits in Mediterranean pine species of group ‘halepensis’
Foliar and cortical terpene profile, and needle gas exchange and water potential of P. halepensis, P. brutia and P. eldarica were compared over three consecutive seasons (1996-1998) in an experimental plantation nearby Firenze (Italy). Terpene percentages in mature tissue (cortex and needle) did not change in response to water stress during summer period and remained stable through seasons and years. Terpene profiles were not affected by seasonal drought, and are thus valuable to characterize Mediterranean pine species of the group “halepensis”. There was a threshold-type response of maximum daily gas exchange to decreasing predawn water potential in all pines. Net photosynthesis and needle conductance were linearly related, regardless of the species
Hub city: aspiration and dispossession in 21st century Colombo
This thesis is an ethnographic study of urban development in Colombo, Sri Lanka. Drawing on 12 months of fieldwork, this manuscript explores the way that the city of Colombo is increasingly being re-imagined by policymakers, developers, government officials and elite residents as a “global city” similar to Singapore or Dubai. As my multi-sited project demonstrates, however, these visions of the new Colombo are far from being the current reality. Through chapters exploring diverse corners of Colombo including: a suspended Chinese-funded waterfront development project; a coastal fishing enclave; a new marketplace opened under the former government; and the city’s luxury apartment buildings, this thesis offers insight both into the varied forms of dispossession faced by the urban poor and working class as well as the aspirational projects designed to appeal to the Colombo elite.
I argue that the primary principle governing Colombo’s urban development is the idea of “hubness,” an aspirational trope which emphasizes connection and mobility, especially across the Indian Ocean region. Rather than taking its island geography as a sign of insularity, many Sri Lankans hope to leverage what is now framed as the country’s “strategic location” to boost its appeal and transform Sri Lanka – and by extension, Colombo – into a major global hub connecting Asia, Africa and the Middle East. I argue that hubness as an ideal is both a spatial and temporal claim. Rather than being a self-evident statement of geography, hubness discourse is also a specific understanding of futurity. These complex entanglements of spatiality and temporality are present in each site.
The ethnographic findings presented in this thesis point to the need to reconsider global city making as a process suffused with uncertainty, rather than as a straightforward, linear evolution. Global cities, I suggest, are not fixed or static entities, but contingent urban forms which are actively created as material and symbolic entities through various forms of dispossession and aspiration
Osservazioni su due casi di poliploidia indotta in Vitis vinifera L. (cv. Barbera)
Vengono descritti gli aspetti citologici ed istologici di due viti cv. Barbera irraggiate con CO60 e present anti fenotipo poliploide.Le analisi compiute hanno riguardato il conteggio dei cromosomi negli apici radicali, l'osservazione degli strati epidermico e subepidermico delle gemme ibernanti, dei granuli pollinici, degli stomi, delle cellule dell'epidermide degli acini.Da tali osservazioni è emerso che un individuo è totalmente tetraploide, mentre il secondo è una chimera periclinale del tipo 2n-4n.Investigations on two cases of induced polyploidy in Vitis vinifera L. (cv. Barbera)The authors describe cytological and histological aspects of two grapevine plants, cv. Barbera, previously irradiated with CO60 and showing polyploid phenotype.The number of chromosomes in the root tip cells, the two first meristematic layers of wintering buds, the size of pollen grains, stornata, and epidermal cells of berries were investigated.The results show that one of them is a tetraploid grape, while the other was found to be a 2n-4n periclinal chimera
Carbon-Based Compounds and Exobiology
The Committee for Planetary and Lunar Explorations (COMPLEX) posed questions related to exobiological exploration of Mars and the possibility of a population of carbonaceous materials in cometary nuclei to be addressed by future space missions. The scientific objectives for such missions are translated into a series of measurements and/or observations to be performed by Martian landers. These are: (1) A detailed mineralogical, chemical, and textural assessment of rock diversity at a landing site; (2) Chemical characterization of the materials at a local site; (3) Abundance of Hydrogen at any accessible sites; (4) Identification of specific minerals that would be diagnostic of aqueous processes; (5) Textual examination of lithologies thought to be formed by aqueous activity; (6) Search for minerals that might have been produced as a result of biological processes; (7) Mapping the distribution, in three dimensions, of the oxidant(s) identified on the Martian surface by the Viking mission; (8) Definition of the local chemical environment; (9) Determination of stable-isotopic ratios for the biogenic elements in surface mineral deposits; (10) Quantitative analysis of organic (non-carbonate) carbon; (11) Elemental and isotopic composition of bulk organic material; (12) Search for specific organic compounds that would yield information about synthetic mechanisms, in the case of prebiotic evolution, and about possible bio-markers, in the case of extinct or extant life; (13) and Coring, sampling, and detection of entrained gases and cosmic-ray induced reaction products at the polar ice cap. A discussion of measurements and/or observations required for cometary landers is included as well
LDEF impact craters formed by carbon-rich impactors: A preliminary report
Two impact craters found in Al from the Long Duration Exposure Facility (LDEF) experiment tray have residues concentrated in the bottoms, along the walls, and on top of overturned rims. Analyses indicate a 'chondritic' compositional signature (Si, S, Ca, Fe, Mg, and Ni) for the bulk residue. In one crater (number 74), round to irregular silicate grains are overlain by carbon. In addition, carbon also partially covers the crater walls, the top of the raised overturned rim, and extends outward from the crater. The second crater (number 31) also contains carbon with similar distribution in and about the crater, although the silicate residue appears to be glassy. Silver, I, K, and F (possibly some of the Ca, S, and Cl) appear to be contaminants as well as analyzed aromatic carbonaceous species associated with the raised rim and the area surrounding the crater. The origin of the impactors is assumed to be extraterrestrial. The existence of impactor residue in two craters implies impact velocities less than or equal to 6 km, based on experimental hypervelocity studies
Employees’ behavior in phishing attacks: what individual, organizational and technological factors matter?
Phishing, as a social engineering attack has become an increasing threat to organizations in cyberspace. To prevent this, a well-designed continuous security training and educational program needs to be established and enforced in organizations. Prior studies have focused on phishing attack from a limited view of technology countermeasure, e-mail’s characteristic, information processing, and securing individual’s behaviors to tackle existing gaps. In this research, we developed a theoretical model of factors that influence users in the clicking of phishing e-mails from a broader Socio-Technical perspective. We applied Protection Motivation Theory (PMT) and habit theory for investigating individual factors, Theory of Planned Behavior (TPB) and Deterrence Theory for investigating organizational and technological factors accordingly. The findings revealed habit and protective countermeasure positively affect clicking on phishing e-mails, whereas, no effect of the procedural countermeasures was evident. The results of this study can be used to design phishing simulation exercise and embedded training for vulnerable employees
The Globe Infrastructure Directory Service
To implement adaptive replication strategies for Web documents, we have developed a wide area resource management system. This system allows servers to be managed on a local and global level. On a local level the system manages information about the resources and services provided by the servers, while on a global level the system allows servers to be searched for, added to, and removed from the system. As part of the system, and also in order to implement adaptive replication strategies, we introduce a hierarchical location representation for network elements such as servers, objects, and clients. This location representation allows us to easily and efficiently find and group network elements based on their location in a worldwide network. Our resource management system can be implemented using standard Internet technologies and has a broader range of applications besides making adaptive replication strategies possible for Web documents
The Internet: Friend, foe or target?
In this concluding chapter, I give an overview of how the Internet, a byproduct of our times, is shaping our culture and society in profound ways. I note some of the major concerns and perils of the Internet age and I conclude by pointing out how and why certain countries are targeting the Internet in terms of increased regulation and surveillance
Binary black hole merger in the extreme mass ratio limit
We discuss the transition from quasi-circular inspiral to plunge of a system
of two nonrotating black holes of masses and in the extreme mass
ratio limit . In the spirit of the Effective One Body
(EOB) approach to the general relativistic dynamics of binary systems, the
dynamics of the two black hole system is represented in terms of an effective
particle of mass moving in a (quasi-)Schwarzschild
background of mass and submitted to an
radiation reaction force defined by Pad\'e resumming high-order Post-Newtonian
results. We then complete this approach by numerically computing, \`a la
Regge-Wheeler-Zerilli, the gravitational radiation emitted by such a particle.
Several tests of the numerical procedure are presented. We focus on
gravitational waveforms and the related energy and angular momentum losses. We
view this work as a contribution to the matching between analytical and
numerical methods within an EOB-type framework.Comment: 14 pages, six figures. Revised version. To appear in the CQG special
issue based around New Frontiers in Numerical Relativity conference, Golm
(Germany), July 17-21 200
Is symmetry identity?
Wigner found unreasonable the "effectiveness of mathematics in the natural
sciences". But if the mathematics we use to describe nature is simply a coded
expression of our experience then its effectiveness is quite reasonable. Its
effectiveness is built into its design. We consider group theory, the logic of
symmetry. We examine the premise that symmetry is identity; that group theory
encodes our experience of identification. To decide whether group theory
describes the world in such an elemental way we catalogue the detailed
correspondence between elements of the physical world and elements of the
formalism. Providing an unequivocal match between concept and mathematical
statement completes the case. It makes effectiveness appear reasonable. The
case that symmetry is identity is a strong one but it is not complete. The
further validation required suggests that unexpected entities might be
describable by the irreducible representations of group theory
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