67 research outputs found

    Tanya Murray Li. Land’s End. Durham: Duke University Press, 2014. 248 pp.

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    Excerpt: Tanya Li’s Land’s End describes the formation of capitalist relations among the Lauje highlanders of central Sulawesi in Indonesia. Based on almost twenty years of field research (1990–2009) in ten hillside neighborhoods in the middle and inner hills, the author traces elusive social and economic transitions in the context of closing frontiers, land loss, and increased reliance on tree crops such as clove and cacao (24). Central to her analysis is an “analytic of conjuncture,” that considers economic elements, material qualities of crops, social boundaries and values, institutional elements, meanings and desires, and unseen spirits as part of a dynamic constellation of forces. By analyzing how these elements collide and intersect, Li traces the histories that shape “structures of feeling” among the Lauje, compelling them to desire the very changes that rob them of their own sustainability (16–18)

    A Simple Perspective on the Mass-Area Relationship in Molecular Clouds

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    Despite over 30 years of study, the mass-area relationship within and among clouds is still poorly understood both observationally and theoretically. Modern extinction datasets should have sufficient resolution and dynamic range to characterize this relationship for nearby molecular clouds, although recent papers using extinction data seem to yield different interpretations regarding the nature and universality of this aspect of cloud structure. In this paper we try to unify these various results and interpretations by accounting for the different ways cloud properties are measured and analyzed. We interpret the mass-area relationship in terms of the column density distribution function and its possible variation within and among clouds. We quantitatively characterize regional variations in the column density PDF. We show that structures both within and among clouds possess the same degree of "universality", in that their PDF means do not systematically scale with structure size. Because of this, mass scales linearly with area.Comment: 10 pages, 8 figures, MNRAS in pres

    A Bubbling Nearby Molecular Cloud: COMPLETE Shells in Perseus

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    We present a study on the shells (and bubbles) in the Perseus molecular cloud using the COMPLETE survey large-scale 12CO(1-0) and 13CO(1-0) maps. The twelve shells reported here are spread throughout most of the Perseus cloud and have circular or arc-like morphologies with a range in radius of about 0.1 to 3 pc. Most of them have not been detected before most likely as maps of the region lacked the coverage and resolution needed to distinguish them. The majority of the shells are coincident with infrared nebulosity of similar shape and have a candidate powering source near the center. We suggest they are formed by the interaction of spherical or very wide-angle winds powered by young stars inside or near the Perseus molecular cloud -a cloud that is commonly considered to be mostly forming low-mass stars. Two of the twelve shells are powered by high-mass stars close to the cloud, while the others appear to be powered by low or intermediate mass stars in the cloud. We argue that winds with a mass loss rate of about 10^-8 to 10^-6 M_sun/yr are required to produce the observed shells. Our estimates indicate that the energy input rate from these stellar winds is similar to the turbulence dissipation rate. We conclude that in Perseus the total energy input from both collimated protostellar outflows and powerful spherical winds from young stars is sufficient to maintain the turbulence in the molecular cloud. Large scale molecular line and IR continuum maps of a sample of clouds will help determine the frequency of this phenomenon in other star forming regions.Comment: 48 pages in total: 16 pages of text and references; 2 pages of tables; 30 figures (one page per figure). Accepted for publication in the Astrophysical Journa

    Hierarchical Structure of Magnetohydrodynamic Turbulence In Position-Position-Velocity Space

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    Magnetohydrodynamic turbulence is able to create hierarchical structures in the interstellar medium that are correlated on a wide range of scales via the energy cascade. We use hierarchical tree diagrams known as dendrograms to characterize structures in synthetic Position-Position-Velocity (PPV) emission cubes of optically thin isothermal magnetohydrodynamic turbulence. We show that the structures and degree of hierarchy observed in PPV space are related to the physics of the gas, i.e. self-gravity and the global sonic and Alfvenic Mach number. Simulations with higher Alfvenic Mach number, self-gravity and supersonic flows display enhanced hierarchical structure. We observed a strong sonic and Alfvenic dependency when we apply the the statistical moments (i.e. mean, variance, skewness, kurtosis) to the dendrogram distribution. Larger magnetic field and sonic Mach number correspond to larger values of the moments. Application of the dendrogram to 3D density cubes, also known as Position-Position-Position cubes (PPP), reveals that the dominant emission contours in PPP and PPV are related for supersonic gas but not for subsonic. We also explore the effects of smoothing, thermal broadening and velocity resolution on the dendrograms in order to make our study more applicable to observational data. These results all point to hierarchical tree diagrams as being a promising additional tool for studying ISM turbulence and star forming regions in the direction of obtaining information on the degree of self-gravity, the Mach numbers and the complicated relationship between PPV and PPP.Comment: submitted to Ap

    Velocity Structure of the ISM as Seen by the Spectral Correlation Function

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    (Abridged) We use the statistical tool known as the ``Spectral Correlation Function" [SCF] to intercompare simulations and observations of the atomic interstellar medium. The simulations considered mimic three distinct sets of physical conditions. One of them (run "ISM") is intended to represent a mixture of cool and warm atomic gas, and includes self-gravity and magnetic fields. For each simulation, H I spectral-line maps are synthesized and intercompared, both with each other, and with observations, using the SCF. We find that, when thermal broadening is large in comparison with fine-scale turbulent velocity structure, it masks sub-thermal velocity sub-structure in the synthesized spectra. The H I observations we use here for comparison are of the North Celestial Pole (NCP) Loop. None of the simulations match the NCP Loop data very well. The most realistic sets of line profiles and SCF statistics comes from artifically rescaling the velocity axis of run ISM. Without rescaling, almost all velocity structure is smeared out by thermal broadening. However, if the velocity axis is expanded by a factor of 6, the SCF distributions of run ISM an the NCP Loop match up fairly well. This means that the ratio of thermal to turbulent pressure in run ISM is much too large as it stands, and that the simulation is deficient in turbulent energy. This is a consequence of run ISM not including the effects of supernovae. We conclude that the SCF is a useful tool for understanding and fine-tuning simulations of interstellar gas, and in particular that realistic simulations of the atomic ISM need to include the effects of energetic stellar winds (e.g. supernovae) in order for the ratio of thermal-to-turbulent pressure to give spectra representative of the observed interstellar medium in our Galaxy.Comment: 25 pages, 24 figures. ApJ Accepted (May 20). Also available at: ftp://www.astrosmo.unam.mx/pub/j.ballesteros/Papers

    Mindfulness-based stress reduction in veterans with PTSD

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    A review of the current literature suggests that different forms of mindfulness-based stress reduction (MBSR) is effective in improving quality of life outcomes for veterans with PTSD

    Reconstruction of primary vertices at the ATLAS experiment in Run 1 proton–proton collisions at the LHC

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    This paper presents the method and performance of primary vertex reconstruction in proton–proton collision data recorded by the ATLAS experiment during Run 1 of the LHC. The studies presented focus on data taken during 2012 at a centre-of-mass energy of √s=8 TeV. The performance has been measured as a function of the number of interactions per bunch crossing over a wide range, from one to seventy. The measurement of the position and size of the luminous region and its use as a constraint to improve the primary vertex resolution are discussed. A longitudinal vertex position resolution of about 30μm is achieved for events with high multiplicity of reconstructed tracks. The transverse position resolution is better than 20μm and is dominated by the precision on the size of the luminous region. An analytical model is proposed to describe the primary vertex reconstruction efficiency as a function of the number of interactions per bunch crossing and of the longitudinal size of the luminous region. Agreement between the data and the predictions of this model is better than 3% up to seventy interactions per bunch crossing

    Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

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    A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

    Impact of Antiparasitic Therapy on Cardiovascular Outcomes in Chronic Chagas Disease. A Systematic Review and Meta-Analysis

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    BACKGROUND: Endemic in more than 20 countries, Chagas disease affects 6.3 million people worldwide, leading to 28,000 new infections and 7700 deaths each year. Previous meta-analyses on antiparasitic treatment need updates to encompass recent studies and to assess key clinically meaningful endpoints. This study aims to evaluate the impact of antitrypanosomal therapy in preventing or reducing disease progression and mortality in chronic Chagas disease. METHODS: We performed a systematic review and meta-analysis of studies reporting the cardiovascular outcomes of antitrypanosomal therapy in patients with chronic Chagas disease. We searched Ovid Embase, Ovid MEDLINE, Ovid Global Health, Scopus, Web of Science Core Collection, Cochrane Library, PubMed, Google Scholar, and Virtual Health Library databases from inception to May 18, 2024. We included aggregated data from randomized controlled studies and observational reports (full articles and abstracts) featuring antiparasitic interventions with benznidazole or nifurtimox compared to a control group. Primary outcomes were electrocardiogram (ECG) changes, disease progression, cardiovascular death, and overall mortality. A customized risk of bias scale assessed the methodological quality of studies, and a random-effects model estimated the pooled risk ratios. This investigation was registered in PROSPERO (CRD42023495755). FINDINGS: Out of 4666 reports screened, 23 met the pre-specified inclusion criteria (8972 participants). Compared to no treatment or placebo, antiparasitic treatment led to a reduction in i) ECG changes (17 studies, 4994 participants: risk ratio (RR): 0.48, 95% CI 0.36-0.66, p \u3c 0.001; INTERPRETATION: We found compelling evidence that antiparasitic treatment significantly reduces the risk of ECG changes, disease progression, cardiovascular death, and overall mortality in chronic Chagas disease. Although the quality of evidence ranges from low to intermediate, with considerable heterogeneity across studies, the potential benefits are substantial. These findings support the broader use of trypanocidal therapy in the management of Chagas disease, though further research remains necessary. FUNDING: This study had no funding source
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