653 research outputs found

    Between Nowhere and Everywhere: The Challenges of Placing the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES)

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    Global Environmental Assessments (GEAs) have become influential processes in environmental governance, with the objective to gather policy-relevant knowledge on environmental issues for decision-makers. This thesis offers the first ethnographic account of the nascent Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES) which, in contrast to earlier GEAs, aims to implement an inclusive model of expertise. Underlying this move are concerns regarding both the effectiveness of GEAs and their democratization. GEAs have also faced numerous criticisms for being dominated by the global North and for failing to consider the diversity of ways of making sense of global environmental change. Drawing on Science and Technology Studies and on the emerging literature on geographies of science, I view science and policy as being mutually entangled, rather than as two separate domains, and conceptualise GEAs as sites of co-production. It is important therefore to study how categories such as ‘science’, ‘policy’, ‘local’ and ‘global’ are produced and to investigate the practices and places through which knowledge is constructed as policy-relevant. I argue that, despite the aspiration to be global institutions that transcend specific national and cultural contexts and interests, GEAs themselves are situated initiatives which produce a ‘view from somewhere’. Using qualitative methods, I examine three processes within IPBES: (1) the choice of location for its Secretariat; (2) the development of its conceptual framework; and (3) the constitution of the Multidisciplinary Expert Panel. Results confirm that IPBES presents a number of innovative features but also reveal significant ambiguities as to whether IPBES is actually ‘opening-up’ its frame of reference and embracing multiple forms of knowledges and expertise. While IPBES aspires to provide the inclusive ‘view from everywhere’, the narrative of science as providing the disinterested ‘view from nowhere’ and the interest-riven context in which it operates undermines its ambitions

    Periodicities in geomagnetic-activity indices and solar-wind parameters, and their possible solar origin

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    We have examined the average behaviors of the solar-wind parameters and the geomagnetic-activity indices. There is a good correlation between the increasing pressure at the magnetopause and the intense magnetospheric disturbances. The ultra-low frequency power spectra for the geomagnetic disturbances have been analyzed and tested. Although the spectrum shows remarkable and stable peaks at the wavelengths 0.5, 0.7, 1.0, 1.3 years, additional significant peaks of 73 d, 1.5 y, 5.1 y and 9.2 y for Ap and 73 d and 1.4 y for the product BSV 2 are also found. However, the 73-d and 5.1-y variations correspond to a non-obvious physical process in the Sun. The Sun may reflect some irregular variations, basically not fundamental, which appear at different times. A comparison of both spectra for periods > 0.5 year suggests different solar origins. Both spectra have different power amplitudes and peaks at different locations. Our study confirmed 1.4–1.5 year oscillations in BSV 2 measurements between 1987 and 2000, and located slightly higher than the Kp peaks (∼ 1.3 y). Although many papers have discussed periodicities in the Ap index, a 9.2-year period has not been reported previously. There is some indication of an association with the coronal-hole variations in the southern hemisphere of the Sun. The conjunction of the Sun observations and SW measurements may be used to estimate the disturbances in the geomagnetic activity in the heliosphere

    Hyperfine Structure of S-States in Muonic Helium Ion

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    Corrections of orders alpha^5 and alpha^6 are calculated in the hyperfine splittings of 1S and 2S - energy levels in the ion of muonic helium. The electron vacuum polarization effects, the nuclear structure corrections and recoil corrections are taken into account. The obtained numerical values of the hyperfine splittings -1334.56 meV (1S state), -166.62 meV (2S state) can be considered as a reliable estimate for the comparison with the future experimental data. The hyperfine splitting interval Delta_{12}=(8 Delta E^{hfs}(2S)- Delta E^{hfs}(1S)) = 1.64 meV can be used for the check of quantum electrodynamics.Comment: 14 pages, 5 figure

    North-South asymmetry of cosmic-ray density gradients throughout the epoch 1955-1991

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    We have computed the magnitude and direction of the asymmetry of cosmic-ray particle density gradient in the heliosphere during the period 1955-1991. Data obtained by twenty-one detectors (neutron monitors, surface and underground muon telescopes) in both terrestrial hemispheres between 1955 and 1991 are analyzed as a function of the sense of interplanetary magnetic field. Their median rigidity of response (Rm) covers the following range: 10 GV � Rm � 185 GV. Significant differences are frequently observed between the diurnal variations measured in toward and away polarity days. The cosmic-ray density gradient displayed insignificant changes near solar maxima and reversed in sign after the reversal polarity periods. The resultant cosmic-ray gradients are: a north-south symmetric gradient which occurred during minima and maxima solar activity epochs, and a N-S asymmetrical gradient which is related to the N-S asymmetry in the activity on the Sun. Northward and southward cosmic-ray latitudinal (or perpendicular) gradients were frequently observed. The solar diurnal phases of toward polarity days north of the HCS (or away) during the period 1981-87 (qA < 0) existed a few hours later than those recorded for toward (or away) days south of HCS during the positive IMF period 1971-78, as well as the time shift depends on the rigidity of the particle. In addition, quite a change occurred on phase for the north neutron monitors and muon telescopes than for those located on the southern hemisphere

    Determining the size of the proton

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    A measurement of the Lamb shift of 49,881.88(76) GHz in muonic hydrogen in conjunction with theoretical estimates of the proton structure effects was recently used to deduce an accurate but rather small radius of the proton. Such an important shift in the understanding of fundamental values needs reconfirmation. Using a different approach with electromagnetic form factors of the proton, we obtain a new expression for the transition energy, Δ=E2P3/2f=2−E2S1/2f=1\Delta = E_{2P_{{3}/{2}}}^{f=2} - E_{2S_{{1}/{2}}}^{f=1}, in muonic hydrogen and deduce a proton radius, rp=0.831r_p = 0.831 fm.Comment: 20 pages LaTe
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