Control Societies

This is a re-working of the video ‘Deleuze’s “Postscript on the Societies of Control”’, which was the second episode of Liquid Theory TV, a series of Internet Protocol Television (IPTV) programmes experimenting with new ways of acting as a ‘public intellectual’ in the current media environment. ‘Deleuze’s “Postscript on the Societies of Control”’ first appeared in Culture Machine 11, 2010. It is accompanied by an introductory essay: http://www.culturemachine.net/index.php/cm/article/view/384/40

Human demography changes in Morocco and environmental imprint during the Holocene

The aim of this work is to reconstruct the periods of growth and decline of human populations in Morocco and their potential impacts on the landscape over the past 10,000 years. In order to estimate the trends in the human population size between 10,000 and 3000 years ago, we used a summed probability distribution (SPD) of radiocarbon dates from a wide range of archaeological sites throughout Morocco. Landscape changes were identified and quantified from a dataset of fossil pollen records. Different anthropogenic pollen markers, as well as natural vegetation groups and taxonomic richness were used to analyse the relationship between long-term trends in human population expansion or regression and type of impact on the landscape. The sub-regions of Morocco have different topographies and climates, which have either favoured or prevented the establishment and/or spread of human populations. In order to identify the areas most significantly impacted by humans and the timing of such impacts, we have reconstructed and compared the same past anthropogenic and landscape proxies along with the population trends within the lowlands and mountainous areas. The lowlands were more strongly impacted earlier in the Holocene than the mountainous areas. Anthropogenic markers indicate that farming expanded in the lowlands during the first major expansion of human populations between ca. 7200 and 6700 cal. yr BP at the start of the Neolithic period. In the Atlas and Rif Mountains, anthropogenic impact is not clearly detectable in any of these areas before 4000 cal. BP. </jats:p

Are models of catalytic removal of O_3 by HO_x accurate? Constraints from in situ measurements of the OH to HO_2 ratio

Measurements of the ratio OH/HO_2, NO, O_3, ClO, and BrO were obtained at altitudes from 15–20 km and latitudes from 15–60°N. A method is presented for interpreting these simultaneous in situ observations that constrains the rates of chemical transformations that 1) are responsible for over half the ozone removal rate in the lower stratosphere via reactions of HO_2 and 2) control the abundance of HO_2 through coupling to nitrogen and halogen radicals. The results show our understanding of the chemical reactions controlling the partitioning of OH and HO_2 is complete and accurate and that the potential effects of “missing chemistry” are strictly constrained in the region of the atmosphere encompassed by the observations. The analysis demonstrates that the sensitivity of the ratio OH/HO_2 to changes in NO is described to within 12% by current models. This reduces by more than a factor of 2 the effect of uncertainty in the coupling of hydrogen and nitrogen radicals on the analysis of the potential effects of perturbations to odd nitrogen in the lower stratosphere

Holocene hydro-climatic variability in the Mediterranean: A synthetic multi-proxy reconstruction

Here we identify and analyze proxy data interpreted to reflect hydro-climatic variability over the last 10,000 years from the Mediterranean region to (1) outline millennial and multi-centennial-scale trends and (2) identify regional patterns of hydro-climatic variability. A total of 47 lake, cave, and marine records were transformed to z-scores to allow direct comparisons between sites, put on a common time scale, and binned into 200-year time slices. Six different regions were identified based on numerical and spatial analyzes of z-scores: S Iberia and Maghreb, N Iberia, Italy, the Balkans, Turkey, and the Levant, and the overall hydro-climate history of each region was reconstructed. N Iberia is largely decoupled from the five other regions throughout the Holocene. Wetter conditions occur in the five other regions between 8500 and 6100 yr BP. After 6000 yr BP, climate oscillated until around 3000 ± 300 yr BP, which seems to have been the overall driest period in the eastern Mediterranean and North Africa. In contrast, Italy and N Iberia seem to have remained wetter during this period. In addition, non-metric multidimensional scaling (nMDS) was applied to 18 long, continuous climate z-score records that span the majority of the Holocene. nMDS axes 1 and 2 illustrate the main trends in the z-score data. The first axis captures a long-term development of drier condition in the Mediterranean from 7900 to 3700 yr BP. Rapid shifts occur in nMDS axis 2 at 6700–6300 BP, 4500–4300 BP, and 3500–3300 BP indicating centennial-scale climate change. Our synthesis highlights a dominant south/east versus north/west Mediterranean hydro-climate dipole throughout the Holocene and therefore confirms that there was no single climate trajectory characterizing the whole Mediterranean basin during the last 10 millennia

The Diurnal Variation of Hydrogen, Nitrogen, and Chlorine Radicals: Implications for the Heterogeneous Production of HNO2

In situ measurements of hydrogen, nitrogen, and chlorine radicals obtained through sunrise and sunset in the lower stratosphere during SPADE are compared to results from a photochemical model constrained by observed concentrations of radical precursors and environmental conditions. Models allowing for heterogeneous hydrolysis of N205 on sulfate aerosols agree with measured concentrations of NO, NO2, and ClO throughout the day, but fail to account for high concentrations of OH and H02 observed near sunrise and sunset. The morning burst of [OH] and [HO2] coincides with the rise of [NO] from photolysis of N02, suggesting a new source of HO, that photolyzes in the near UV (350 to 400 nm) spectral region. A model that allows for the heterogeneous production of HN02 results in an excellent simulation of the diurnal variations of [OH] and [HO2]

Migration Patterns, Use of Stopover Areas, and Austral Summer Movements of Swainson\u27s Hawks

From 1995 to 1998, we tracked movements of adult Swainson’s Hawks (Buteo swainsoni), using satellite telemetry to characterize migration, important stopover areas, and movements in the austral summer. We tagged 46 hawks from July to September on their nesting grounds in seven U.S. states and two Canadian provinces. Swainson’s Hawks followed three basic routes south on a broad front, converged along the east coast of central Mexico, and followed a concentrated corridor to a communal area in central Argentina for the austral summer. North of 20°N, southward and northward tracks differed little for individuals from east of the continental divide but differed greatly (up to 1700 km) for individuals from west of the continental divide. Hawks left the breeding grounds mid-August to mid-October; departure dates did not differ by location, year, or sex. Southbound migration lasted 42 to 98 days, northbound migration 51 to 82 days. Southbound, 36% of the Swainson’s Hawks departed the nesting grounds nearly 3 weeks earlier than the other radio-marked hawks and made stopovers 9.0–26.0 days long in seven separate areas, mainly in the southern Great Plains, southern Arizona and New Mexico, and northcentral Mexico. The birds stayed in their nonbreeding range for 76 to 128 days. All used a core area in central Argentina within 23% of the 738 800-km2 austral summer range, where they frequently moved long distances (up to 1600 km). Conservation of Swainson’s Hawks must be an international effort that considers habitats used during nesting and non-nesting seasons, including migration stopovers

The response of ClO radical concentrations to variations in NO_2 radical concentrations in the lower stratosphere

The response of ClO concentrations to changes in NO_2 concentrations has been inferred from simultaneous observations of [ClO], [NO], [NO_2] and [O_3] in the mid-latitude lower stratosphere. This analysis demonstrates that [ClO] is inversely correlated with [NO_2], consistent with formation and photolysis of [ClONO_2]. A factor of ten range in the concentration of NO_2 was sampled (0.1 to 1×10^9 mol/cm^3), with a comparable range in the ratio of [ClO] to total available inorganic chlorine (1% ≤ [ClO]/[Cl_y] ≤ 5%). This analysis leads to an estimate of [ClONO_2]/[Cl_y] = 0.12 (×/÷2), in the mid-latitude, lower-stratospheric air masses sampled

The distribution of hydrogen, nitrogen, and chlorine radicals in the lower stratosphere: Implications for changes in O_3 due to emission of NO_y from supersonic aircraft

In situ measurements of hydrogen, nitrogen, and chlorine radicals obtained in the lower stratosphere during SPADE are compared to results from a photochemical model that assimilates measurements of radical precursors and environmental conditions. Models allowing for heterogeneous hydrolysis of N_2O_5 agree well with measured concentrations of NO and ClO, but concentrations of HO_2 and OH are underestimated by 10 to 25%, concentrations of NO_2 are overestimated by 10 to 30%, and concentrations of HCl are overestimated by a factor of 2. Discrepancies for [OH] and [HO_2] are reduced if we allow for higher yields of O(^1D) from O_3 photolysis and for heterogeneous production of HNO_2. The data suggest more efficient catalytic removal of O_3 by hydrogen and halogen radicals relative to nitrogen oxide radicals than predicted by models using recommended rates and cross sections. Increases in [O_3] in the lower stratosphere may be larger in response to inputs of NO_y from supersonic aircraft than estimated by current assessment models

The diurnal variation of hydrogen, nitrogen, and chlorine radicals: implications for the heterogeneous production of HNO_2

In situ measurements of hydrogen, nitrogen, and chlorine radicals obtained through sunrise and sunset in the lower stratosphere during SPADE are compared to results from a photochemical model constrained by observed concentrations of radical precursors and environmental conditions. Models allowing for heterogeneous hydrolysis of N_(2)O_(5) on sulfate aerosols agree with measured concentrations of NO, NO_(2), and ClO throughout the day, but fail to account for high concentrations of OH and HO_(2) observed near sunrise and sunset. The morning burst of [OH] and [HO_(2)] coincides with the rise of [NO] from photolysis of NO_(2), suggesting a new source of HO_(x) that photolyzes in the near UV (350 to 400 nm) spectral region. A model that allows for the heterogeneous production of HNO_(2) results in an excellent simulation of the diurnal variations of [OH] and [HO_(2)]