2,042 research outputs found
Demonstration of angular anisotropy in the output of Thematic Mapper
There is a dependence of TM output (proportional to scene radiance in a manner which will be discussed) upon season, upon cover type and upon view angle. The existence of a significant systematic variation across uniform scenes in p-type (radiometrically and geometrically pre-processed) data is demonstrated. Present pre-processing does remove the effects and the problem must be addressed because the effects are large. While this is in no way attributable to any shortcomings in the thematic mapper, it is an effect which is sufficiently important to warrant more study, with a view to developing suitable pre-processing correction algorithms
Migration and animal husbandry: Competing or complementary livelihood strategies. Evidence from Kyrgyzstan
Animal husbandry and labour migration are important livelihood strategies for a large proportion of the rural population in developing countries. Up to now, the two strategies have usually been studied by looking at either one or the other; their interlinkages have rarely been examined. Based on a case study in rural Kyrgyzstan, the aim of this paper is to explore the links between animal husbandry and labour migration. Results show that for most rural households, livestock is crucial yet not sufficient to make a living. Therefore, many people diversify their income sources by migrating to work elsewhere. This generates cash for daily expenses and the acquisition of new livestock, but also leads to an absence of workforce in households. Yet since remittances usually exceed the expenses for hiring additional workforce, most people consider migration profitable. From a socio-economic point of view, migration and animal husbandry can thus be considered important complementary livelihood strategies for the rural Kyrgyz population, at least for the time being. In the long term, however, the failure of young migrants to return to rural places and their settlement in urban areas might also cause remittance dependency and lead to an increasing lack of qualified labour. From an environmental point of view, the investment of remittances into animal husbandry poses challenges to sustainable pasture management. Increasing livestock numbers in rural areas raise pressure on pasture resources. Since most people consider animal husbandry their main future prospect while continuing to use pastures in a fairly unsustainable way, this may further exacerbate the over-utilization of pastures in future
Coordination patterns reveal online political astroturfing across the world.
Online political astroturfing-hidden information campaigns in which a political actor mimics genuine citizen behavior by incentivizing agents to spread information online-has become prevalent on social media. Such inauthentic information campaigns threaten to undermine the Internet's promise to more equitable participation in public debates. We argue that the logic of social behavior within the campaign bureaucracy and principal-agent problems lead to detectable activity patterns among the campaign's social media accounts. Our analysis uses a network-based methodology to identify such coordination patterns in all campaigns contained in the largest publicly available database on astroturfing published by Twitter. On average, 74% of the involved accounts in each campaign engaged in a simple form of coordination that we call co-tweeting and co-retweeting. Comparing the astroturfing accounts to various systematically constructed comparison samples, we show that the same behavior is negligible among the accounts of regular users that the campaigns try to mimic. As its main substantive contribution, the paper demonstrates that online political astroturfing consistently leaves similar traces of coordination, even across diverse political and country contexts and different time periods. The presented methodology is a reliable first step for detecting astroturfing campaigns
A method to polarise antiprotons in storage rings and create polarised antineutrons
An intense circularely polarised photon beam interacts with a cooled
antiproton beam in a storage ring. Due to spin dependent absorption cross
sections for the reaction gamma+antiproton > pi- + antineutron a built-up of
polarisation of the stored antiprotons takes place. Figures-of-merit around 0.1
can be reached in principle over a wide range of antiproton energies. In this
process antineutrons with Polarisation > 70% emerge. The method is presented
for the case of 300 MeV/c cooled antiproton beam
Secure Vehicular Communication Systems: Implementation, Performance, and Research Challenges
Vehicular Communication (VC) systems are on the verge of practical
deployment. Nonetheless, their security and privacy protection is one of the
problems that have been addressed only recently. In order to show the
feasibility of secure VC, certain implementations are required. In [1] we
discuss the design of a VC security system that has emerged as a result of the
European SeVeCom project. In this second paper, we discuss various issues
related to the implementation and deployment aspects of secure VC systems.
Moreover, we provide an outlook on open security research issues that will
arise as VC systems develop from today's simple prototypes to full-fledged
systems
Calculation of and Couplings in QCD Sum Rules
We calculate the coupling constants, and $, which is also important
in the calculation of the S_{11}(1535) mass itself within the sum rule
approach.Comment: 8 pages (no figure), revte
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