7,726 research outputs found

    Peasant enterprise and processes of monetisation in highland Peru: the case of pucara

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    The main theme of the thesis can be summarised as an attempt to explore some classical theoretical statementsabout the so-called 'progressive' character of commercial activities in the Highlands of Peru, and on the other hand,to examine certain methodological issues arising from earlier investigations in the area (see Arguedas, 1957; AlersMontalvo,1967; Adams, 1959; Long and Roberts, 1974, and 1978). In order to explore these two dimensions, the analysis concentrates upon determining the functions of small-scale commercial activities in a rural context, relating them to the existing agrarian structure, patterns of income distribution, consumption and diversification of economic activities at community level, and more systematically to processes of distribution and exchange at regional and national levels. The study focuses upon the role of rural, non-agricultural activities, a persisting feature of the Peruvian economy, which has provided the basis for the development of small-scale, economically dynamic entreprise that has, on the one hand impeded proletarianisation in the rural sector, and yeton the other, increased socio-economic differentiation. To understand this apparently contradictory dynamic, the nature of subordinated groups within the structure of underdevelopment is examined. It is argued that one must not consider such groups merely as a target for manipulation by capitalist interests, which has been the tendency of some writers from both the modernisation and dependency schools. Indeed, these subordinated groups (consisting in the rural sector of small-scale agriculturalists and traders etc.) have throughout much of the history of Peru has been placed outside the principal lines of development strategy adopted by the State and external interests. A sounder interpretation rests, I believe, upon a systematic analysis of the economic and social functions of small-scale enterprise, which, given the weakness of Peruvian capitalism, assumes a complementary dynamic which in certain important ways counterbalances the penetration of the capitalist mode of production The co-existence and inter-penetration of various capitalist and non-capitalist relations in Peruvian society gives a 'flexibility' to social and economic processes: it is this flexibility that is studied in depth through the analysis of small-scale commercial activities. The argument is developed using detailed field data concerning the village of Pucara in the Mantaro region, concentrating on the importance of cash income for the functioning of the household economy, the role of non-agricultural occupations, and the part played by kinship and interpersonal networks in the process of social reproduction of the household unit

    Assessing molecular outflows and turbulence in the protostellar cluster Serpens South

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    Molecular outflows driven by protostellar cluster members likely impact their surroundings and contribute to turbulence, affecting subsequent star formation. The very young Serpens South cluster consists of a particularly high density and fraction of protostars, yielding a relevant case study for protostellar outflows and their impact on the cluster environment. We combined CO J=10J=1-0 observations of this region using the Combined Array for Research in Millimeter-wave Astronomy (CARMA) and the Institut de Radioastronomie Millim\'{e}trique (IRAM) 30 m single dish telescope. The combined map allows us to probe CO outflows within the central, most active region at size scales of 0.01 pc to 0.8 pc. We account for effects of line opacity and excitation temperature variations by incorporating 12^{12}CO and 13^{13}CO data for the J=10J=1-0 and J=32J=3-2 transitions (using Atacama Pathfinder Experiment and Caltech Submillimeter Observatory observations for the higher CO transitions), and we calculate mass, momentum, and energy of the molecular outflows in this region. The outflow mass loss rate, force, and luminosity, compared with diagnostics of turbulence and gravity, suggest that outflows drive a sufficient amount of energy to sustain turbulence, but not enough energy to substantially counter the gravitational potential energy and disrupt the clump. Further, we compare Serpens South with the slightly more evolved cluster NGC 1333, and we propose an empirical scenario for outflow-cluster interaction at different evolutionary stages.Comment: 26 pages, 15 figures, accepted for publication in the Astrophysical Journa

    The UN in the lab

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    We consider two alternatives to inaction for governments combating terrorism, which we term Defense and Prevention. Defense consists of investing in resources that reduce the impact of an attack, and generates a negative externality to other governments, making their countries a more attractive objective for terrorists. In contrast, Prevention, which consists of investing in resources that reduce the ability of the terrorist organization to mount an attack, creates a positive externality by reducing the overall threat of terrorism for all. This interaction is captured using a simple 3×3 “Nested Prisoner’s Dilemma” game, with a single Nash equilibrium where both countries choose Defense. Due to the structure of this interaction, countries can benefit from coordination of policy choices, and international institutions (such as the UN) can be utilized to facilitate coordination by implementing agreements to share the burden of Prevention. We introduce an institution that implements a burden-sharing policy for Prevention, and investigate experimentally whether subjects coordinate on a cooperative strategy more frequently under different levels of cost sharing. In all treatments, burden sharing leaves the Prisoner’s Dilemma structure and Nash equilibrium of the game unchanged. We compare three levels of burden sharing to a baseline in a between-subjects design, and find that burden sharing generates a non-linear effect on the choice of the efficient Prevention strategy and overall performance. Only an institution supporting a high level of mandatory burden sharing generates a significant improvement in the use of the Prevention strategy

    SMA and Spitzer Observations of Bok Glouble CB17: A Candidate First Hydrostatic Core?

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    We present high angular resolution SMA and Spitzer observations toward the Bok globule CB17. SMA 1.3mm dust continuum images reveal within CB17 two sources with an angular separation of about 21" (about 5250 AU at a distance of 250 pc). The northwestern continuum source, referred to as CB17 IRS, dominates the infrared emission in the Spitzer images, drives a bipolar outflow extending in the northwest-southeast direction, and is classified as a low luminosity Class0/I transition object (L_bol ~ 0.5 L_sun). The southeastern continuum source, referred to as CB17 MMS, has faint dust continuum emission in the SMA 1.3mm observations (about 6 sigma detection; ~3.8 mJy), but is not detected in the deep Spitzer infrared images at wavelengths from 3.6 to 70 micron. Its bolometric luminosity and temperature, estimated from its spectral energy distribution, are less than 0.04 L_sun and 16 K, respectively. The SMA CO(2-1) observations suggest that CB17 MMS may drive a low-velocity molecular outflow (about 2.5 km/s), extending in the east-west direction. Comparisons with prestellar cores and Class0 protostars suggest that CB17 MMS is more evolved than prestellar cores but less evolved than Class0 protostars. The observed characteristics of CB17 MMS are consistent with the theoretical predictions from radiative/magneto hydrodynamical simulations of a first hydrostatic core, but there is also the possibility that CB17 MMS is an extremely low luminosity protostar deeply embedded in an edge-on circumstellar disk. Further observations are needed to study the properties of CB17 MMS and to address more precisely its evolutionary stage.Comment: 33 pages, 11 figures, to be published by Ap

    Jets and Outflows From Star to Cloud: Observations Confront Theory

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    In this review we focus on the role jets and outflows play in the star and planet formation process. Our essential question can be posed as follows: are jets/outflows merely an epiphenomenon associated with star formation or do they play an important role in mediating the physics of assembling stars both individually and globally? We address this question by reviewing the current state of observations and their key points of contact with theory. Our review of jet/outflow phenomena is organized into three length-scale domains: Source and Disk Scales (0.11020.1-10^2 au) where the connection with protostellar and disk evolution theories is paramount; Envelope Scales (10210510^2-10^5 au) where the chemistry and propagation shed further light on the jet launching process, its variability and its impact on the infalling envelope; Parent Cloud Scales (10510610^5-10^6 au) where global momentum injection into cluster/cloud environments become relevant. Issues of feedback are of particular importance on the smallest scales where planet formation regions in a disk may be impacted by the presence of disk winds, irradiation by jet shocks or shielding by the winds. Feedback on envelope scales may determine the final stellar mass (core-to-star efficiency) and envelope dissipation. Feedback also plays an important role on the larger scales with outflows contributing to turbulent support within clusters including alteration of cluster star formation efficiencies (feedback on larger scales currently appears unlikely). A particularly novel dimension of our review is that we consider results on jet dynamics from the emerging field of High Energy Density Laboratory Astrophysics (HEDLA). HEDLA is now providing direct insights into the 3-D dynamics of fully magnetized, hypersonic, radiative outflows.Comment: Accepted for publication as a chapter in Protostars and Planets VI, University of Arizona Press (2014), eds. H. Beuther, R. Klessen, C. Dullemond, Th. Hennin

    Critical Comparison between Modified Monier-Williams and Electrochemical Methods to Determine Sulfite in Aqueous Solutions

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    In the present work, known concentration of sulfite aqueous solutions in the presence and absence of gallic acid was measured to corroborate the validity of modified Monier-Williams method. Free and bound-sulfite was estimated by differential pulse voltammetry. To our surprise, the modified Monier-Williams method (also known as aspiration method) showed to be very inaccurate for free-sulfite, although suitable for bound-sulfite determination. The differential pulse approach, using the standard addition method and a correction coefficient, proved to be swift, cheap, and very precise and accurate
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