619 research outputs found
Cooperation and defection in ghetto
We consider ghetto as a community of people ruled against their will by an
external power. Members of the community feel that their laws are broken.
However, attempts to leave ghetto makes their situation worse. We discuss the
relation of the ghetto inhabitants to the ruling power in context of their
needs, organized according to the Maslow hierarchy. Decisions how to satisfy
successive needs are undertaken in cooperation with or defection the ruling
power. This issue allows to construct the tree of decisions and to adopt the
pruning technique from the game theory. Dynamics of decisions can be described
within the formalism of fundamental equations. The result is that the strategy
of defection is stabilized by the estimated payoff.Comment: 12 pages, 2 figure
Cladding mode coupling in highly localized fiber Bragg gratings: modal properties and transmission spectra
The spectral characteristics of a fiber Bragg grating (FBG) with a
transversely inhomogeneous refractive index profile, differs con- siderably
from that of a transversely uniform one. Transmission spectra of inhomogeneous
and asymmetric FBGs that have been inscribed with focused ultrashort pulses
with the so-called point-by-point technique are investigated. The cladding mode
resonances of such FBGs can span a full octave in the spectrum and are very
pronounced (deeper than 20dB). Using a coupled-mode approach, we compute the
strength of resonant coupling and find that coupling into cladding modes of
higher azimuthal order is very sensitive to the position of the modification in
the core. Exploiting these properties allows precise control of such
reflections and may lead to many new sensing applications.Comment: Submission to OE, 16 pages, 6 figure
Radiation Science Using Z-Pinch X-Rays
Present-day Z-pinch experiments generate 200 TW peak power, 5â10 ns duration x-ray bursts that provide new possibilities to advance radiation science. The experiments support both the underlying atomic and plasma physics, as well as inertial confinement fusion and astrophysics applications. A typical configuration consists of a sample located 1â10 cm away from the pinch, where it is heated to 10â100 eV temperatures by the pinch radiation. The spectrally-resolved sample-plasma absorption is measured by aiming x-ray spectrographs through the sample at the pinch. The pinch plasma thus both heats the sample and serves as a backlighter. Opacitymeasurements with this source are promising because of the large sample size, the relatively long radiation duration, and the possibility to measureopacities at temperatures above 100 eV. Initial opacity experiments are under way with CH-tamped NaBr foil samples. The Na serves as a thermometer and absorption spectra are recorded to determine the opacity of Br with a partially-filled M-shell. The large sample size and brightness of the Z pinch as a backlighter are also exploited in a novel method measuring re-emission from radiation-heated gold plasmas. The method uses a CH-tamped layered foil with Al+MgF2 facing the radiationsource. A gold backing layer that covers a portion of the foil absorbs radiation from the source and provides re-emission that further heats the Al+MgF2. The Al and Mg heating is measured using space-resolved Kα absorption spectroscopy and the difference between the two regions enables a determination of the gold re-emission. Measurements are also performed at lower densities where photoionization is expected to dominate over collisions. Absorption spectra have been obtained for both Ne-like Fe and He-like Ne, confirming production of the relevant charge states needed to benchmark atomic kinetics models. Refinement of the methods described here is in progress to address multiple issues for radiation science
Pedestrian, Crowd, and Evacuation Dynamics
This contribution describes efforts to model the behavior of individual
pedestrians and their interactions in crowds, which generate certain kinds of
self-organized patterns of motion. Moreover, this article focusses on the
dynamics of crowds in panic or evacuation situations, methods to optimize
building designs for egress, and factors potentially causing the breakdown of
orderly motion.Comment: This is a review paper. For related work see http://www.soms.ethz.c
Point-by-point inscription of 250-nm-period structure in bulk fused silica by tightly-focused femtosecond UV pulses: experiment and numerical modeling
By conducting point-by-point inscription in a continuously moving slab of a pure fused silica at the optimal depth (170 ĂÂŒm depth below the surface), we have fabricated a 250-nm-period nanostructure with 30 nJ, 300 fs, 1 kHz pulses from frequency-tripled Ti:sapphire laser. This is the smallest value for the inscribed period yet reported, and has been achieved with radical improvement in the quality of the inscribed nanostructures in comparison with previous reports. The performed numerical modeling confirms the obtained experimental results
Theorizing transnational labour markets. A research heuristic based on the new economic sociology
Mense-Petermann U. Theorizing transnational labour markets. A research heuristic based on the new economic sociology. Global Networks. 2020;20(3):410-433.In this article, I suggest that transnational labour markets are characterized by their multiâlayered embeddedness, not only in national but also in transnational institutional settings. Hence, the national institutional factors formerly at the centre of sociological labour market theories insufficiently explain the newly emerging transnational labour markets. To account for the full complexity and institutional context of the latter, I propose an inductive theoretical approach to transnational labour markets and develop a research heuristic to instruct empirical studies about particular transnational labour markets and inductive theory building. This heuristic draws on analytical categories as developed by the new economic sociology of markets. The empirical example of the transnational labour market that matches eastern European workers to jobs in the German meat industry serves to illustrate how one can use this heuristic, which reveals some preliminary features of transnational labour markets compared with national ones, as well as some research gaps to be addressed by future studies
Inclusive education for Internally Displaced Children in Kenya::Children perceptions of their learning and development needs in post-conflict schooling
Abstract The Kenyan society has been characterised by tribal-political-instigated violence since the declaration of multiparty democracy in 1991. The 2007/8 post-election violence (PEV) particularly saw the scattering of families where some children lost months or years of schooling; others were permanently excluded from education, while the participation and achievement of those arriving in school were characterised by complex needs and experiences. This paper aims to analyse literature and report on findings from creative activities with 16 conflict-affected children (9â12Â years) regarding their experiences and understandings of inclusive education during their post-conflict school-life. I conducted an intrinsic case study with aspects of ethnography in a post-conflict community primary school in Kenya whose majority (71%) pupil population was attributed to internal displacement following the 2007/8 PEV. Children perceived inclusive education in regard to their own learning and development needs as involving access and acceptance in the new school community, social-emotional development, âpeer-keepingâ and community-consciousness. Whilst valuing their teachersâ pursuit for inclusion-sensitive practices, childrenâs understanding of their own circumstances resulted in group-made strategies like âpeer-keepingâ and peer-constructed rules of interaction, helping them negotiate systemic constrains and distortion of values. This study underscores the fundamental role of children in social integration in post-conflict circumstances
Inside Organizations: Pricing, Politics, and Path Dependence
When economists have considered organizations, much attention has focused on the boundary of the firm, rather than its internal structures and processes. In contrast, this review sketches three approaches to the economic theory of internal organizationâone substantially developed, another rapidly emerging, and a third on the horizon. The first approach (pricing) applies Pigou's prescription: If markets get prices wrong, then the economist's job is to fix the prices. The second approach (politics) considers environments where important actions inside organizations simply cannot be priced, so power and control become central. Finally, the third approach (path dependence) complements the first two by shifting attention from the between variance to the within. That is, rather than asking how organizations confronting different circumstances should choose different structures and processes, the focus here is on how path dependence can cause persistent performance differences among seemingly similar enterprises
Social Pedagogy: An Approach Without Fixed Recipes
A historical and theoretical reconstruction of the specificity and peculiarity of the discipline of social pedagogy, as it has developed in Denmark. Social pedagogy takes its departure from the idea that the individual person and the community are complementary but at the same time opposed to each other, so the task of social pedagogy is rebalancing the dynamics between the two. Social pedagogy is also characterised as a discipline with three dimensions: a practical dimension, a theoretical dimension and a professional dimension. The
professionalâs task is neither to apply theory in practice nor to uphold the usual practice; it is to mediate between theory and practice. The specificity of the discipline gives rise to particular challenges and
dilemmas that theorists make understandable and transparent and practitioners have to deal with. A big challenge for social pedagogy is the quest for evidence-based methods that overrides the specificity of the
social pedagogical approach. Balancing different forms of knowledge implies that programmes and methods are used as inspiration that can be contained in a social pedagogical approach
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