230 research outputs found
Environmentally sustainable houshold consumption: From aggregate environmental pressures to indicators for priority fields of action
During the UNCED conference in Rio de Janeiro 1992 unsustainable consumption and production patterns were identified as one of the key driving forces behind theunsustainable development of the world (Agenda 21, chapter 4). These consumption and production patterns are based on the European model of industrialisation, spread around the globe in the age of colonisation and brought toextremes by the upper-class of industrialised societies, in particular in the United States, but also in a number of countries in the South. Therefore, all states of theworld share the task of developing sustainable consumption and productionpatterns, while particular responsibility rests with the industrialised nations of Europe, North America and Japan. They, and the thriving but small rich elite in the transition countries and in the South, form a global consumer society, with shared products, lifestyles and aspirations. As it is essential to support the transition towards sustainable development byproviding the proper information in an operational manner, the UNCED conference has called for the development of suitable means of information, and in particular for the development of sustainability indicators applicable throughout the world (Agenda 21, chapter 40). The UNDESA set of indicators for changingconsumption and production patterns offers helpful advice in this regard but stilllacks the theoretical underpinning needed to consistently complete it by definingthe few still missing indicators.This paper undertakes to suggest such a methodology based on the environmental space concept. It derives a set of science based indicators from this approachwhich are easily applicable in everyday life and analyses the environmentalrelevance of the consumption clusters chosen for analysis as well as the relevanceof the phenomena characterised by the indicators suggested. As households arejust one actor in the field of consumption, a qualitative assessment of influences isperformed and the result depicting the key actors for each environmentallyrelevant consumption cluster is presented as an actor matrix. --
Operator Representations on Quantum Spaces
In this article we present explicit formulae for q-differentiation on quantum
spaces which could be of particular importance in physics, i.e., q-deformed
Minkowski space and q-deformed Euclidean space in three or four dimensions. The
calculations are based on the covariant differential calculus of these quantum
spaces. Furthermore, our formulae can be regarded as a generalization of
Jackson's q-derivative to three and four dimensions.Comment: 34 pages, Latex, major modifications to improve clarity, corrected
typo
Effect of relativistic acceleration on localized two-mode Gaussian quantum states
We study how an arbitrary Gaussian state of two localized wave packets,
prepared in an inertial frame of reference, is described by a pair of uniformly
accelerated observers. We explicitly compute the resulting state for
arbitrarily chosen proper accelerations of the observers and independently
tuned distance between them. To do so, we introduce a generalized Rindler frame
of reference and analytically derive the corresponding state transformation as
a Gaussian channel. Our approach provides several new insights into the
phenomenon of vacuum entanglement such as the highly non-trivial effect of
spatial separation between the observers including sudden death of
entanglement. We also calculate the fidelity of the two-mode channel for
non-vacuum Gaussian states and obtain bounds on classical and quantum
capacities of a single-mode channel. Our framework can be directly applied to
any continuous variable quantum information protocol in which the effects of
acceleration or gravity cannot be neglected.Comment: 21 pages, 13 figures. A few typos correcte
q-Integration on Quantum Spaces
In this article we present formulae for q-integration on quantum spaces which
could be of particular importance in physics, i.e. q-deformed Minkowski space
and q-deformed Euclidean space in 3 or 4 dimensions. Furthermore, our formulae
can be regarded as a generalization of Jackson's q-integral to 3 and 4
dimensions and provide a new possibility for an integration over the whole
space being invariant under translations and rotations.Comment: 38 pages, Latex, corrected typos, major modifications to improve
clarit
Social Interactions vs Revisions, What is important for Promotion in Wikipedia?
In epistemic community, people are said to be selected on their knowledge
contribution to the project (articles, codes, etc.) However, the socialization
process is an important factor for inclusion, sustainability as a contributor,
and promotion. Finally, what does matter to be promoted? being a good
contributor? being a good animator? knowing the boss? We explore this question
looking at the process of election for administrator in the English Wikipedia
community. We modeled the candidates according to their revisions and/or social
attributes. These attributes are used to construct a predictive model of
promotion success, based on the candidates's past behavior, computed thanks to
a random forest algorithm.
Our model combining knowledge contribution variables and social networking
variables successfully explain 78% of the results which is better than the
former models. It also helps to refine the criterion for election. If the
number of knowledge contributions is the most important element, social
interactions come close second to explain the election. But being connected
with the future peers (the admins) can make the difference between success and
failure, making this epistemic community a very social community too
Confronting Finsler space-time with experiment
Within all approaches to quantum gravity small violations of the Einstein
Equivalence Principle are expected. This includes violations of Lorentz
invariance. While usually violations of Lorentz invariance are introduced
through the coupling to additional tensor fields, here a Finslerian approach is
employed where violations of Lorentz invariance are incorporated as an integral
part of the space-time metrics. Within such a Finslerian framework a modified
dispersion relation is derived which is confronted with current high precision
experiments. As a result, Finsler type deviations from the Minkowskian metric
are excluded with an accuracy of 10^{-16}.Comment: To be published in General Relativity and Gravitatio
Relativistic quantum clocks
The conflict between quantum theory and the theory of relativity is
exemplified in their treatment of time. We examine the ways in which their
conceptions differ, and describe a semiclassical clock model combining elements
of both theories. The results obtained with this clock model in flat spacetime
are reviewed, and the problem of generalizing the model to curved spacetime is
discussed, before briefly describing an experimental setup which could be used
to test of the model. Taking an operationalist view, where time is that which
is measured by a clock, we discuss the conclusions that can be drawn from these
results, and what clues they contain for a full quantum relativistic theory of
time.Comment: 12 pages, 4 figures. Invited contribution for the proceedings for
"Workshop on Time in Physics" Zurich 201
Systemic pro-inflammatory cytokine status following therapeutic hypothermia in a piglet hypoxia-ischemia model
BACKGROUND: Inflammatory cytokines are implicated in the pathogenesis of perinatal hypoxia-ischemia (HI). The influence of hypothermia (HT) on cytokines after HI is unclear. Our aim was to assess in a piglet asphyxia model, under normothermic (NT) and HT conditions: (i) the evolution of serum cytokines over 48 h and (ii) cerebrospinal fluid (CSF) cytokine levels at 48 h; (iii) serum pro/anti-inflammatory cytokine profile over 48 h and (iv) relation between brain injury measured by magnetic resonance spectroscopy (MRS) and brain TUNEL positive cells with serum cytokines, serum pro/anti-inflammatory cytokines and CSF cytokines. METHODS: Newborn piglets were randomized to NT (n = 5) or HT (n = 6) lasting 2-26 h after HI. Serum samples were obtained 4-6 h before, during and at 6-12 h intervals after HI; CSF was obtained at 48 h. Concentrations of interleukin (IL)-1beta, -4, -6, -8, -10 and TNF-alpha were measured and pro/anti-inflammatory status compared between groups. White matter and thalamic voxel lactate/N-acetyl aspartate (Lac/NAA) (a measure of both oxidative metabolism and neuronal loss) were acquired at baseline, after HI and at 24 and 36 h. RESULTS: Lac/NAA was reduced at 36 h with HT compared to NT (p = 0.013 basal ganglia and p = 0.033 white matter). HT showed lower serum TNF-alpha from baseline to 12 h (p < 0.05). Time-matched (acquired within 5 h of each other) serum cytokine and MRS showed correlations between Lac/NAA and serum IL-1beta and IL-10 (all p < 0.01). The pro/anti-inflammatory ratios IL-1beta/IL-10, IL-6/IL-10, IL-4/IL-10 and IL-8/IL-10 were similar in NT and HT groups until 36 h (24 h for IL-6/IL-10); after this, 36 h pro/anti-inflammatory cytokine ratios in the serum were higher in HT compared to NT (p < 0.05), indicating a pro-inflammatory cytokine surge after rewarming in the HT group. In the CSF at 48 h, IL-8 was lower in the HT group (p < 0.05). At 48 h, CSF TNF-alpha correlated with Lac/NAA (p = 0.02) and CSF IL-8 correlated with white matter TUNEL positive cell death (p = 0.04). CONCLUSIONS: Following cerebral HI, there was a systemic pro-inflammatory surge after rewarming in the HT group, which is counterintuitive to the putative neuroprotective effects of HT. While serum cytokines were variable, elevations in CSF inflammatory cytokines at 48 h were associated with MRS Lac/NAA and white matter cell death
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