Social Networks and Transnational Social Fields: A Review of Quantitative and Mixed-Methods Approaches

Ashton Verdery acknowledges assistance provided by the Population Research Institute, which is supported by an infrastructure grant by the Eunice Kennedy Shriver National Institute of Child Health and Human Development (R24-HD041025), and the Institute for CyberScience at Penn State University.Scholars of transnationalism have argued that migrants create transnational social fields or spaces that connect their place of origin to destination areas. Despite the centrality that social networks have in the definition of these concepts, quantitative and mixed-methods social network research is rare in research on transnationalism. This situation, however, has changed over the last decade, and the transnational social networks of migrants have been studied with multiple methodologies. So far, this literature has not been systematically evaluated. With the aim of taking stock of this research, we classify the literature into four types of approaches (individual, household, dyad/small set, and community) and review their distinct contributions regarding the functioning of immigrants' transnational networks, as well as the relative strengths and limitations of each approach. On the basis of our analysis, we discuss pathways for future investigation

Hyperbaric Oxygen Therapy: Solution for Difficult to Heal Acute Wounds? Systematic Review

Hyperbaric oxygen therapy (HBOT) is used to treat various wound types. However, the possible beneficial and harmful effects of HBOT for acute wounds are unclear. We undertook a systematic review to evaluate the effectiveness of HBOT compared to other interventions on wound healing and adverse effects in patients with acute wounds. To detect all available randomized controlled trials (RCTs) we searched five relevant databases up to March 2010. Trial selection, quality assessment, data extraction, and data synthesis were conducted by two of the authors independently. We included five trials, totaling 360 patients. These trials, with some methodologic flaws, included different kinds of wound and focused on different outcome parameters, which prohibited meta-analysis. A French trial (n = 36 patients) reported that significantly more crush wounds healed with HBOT than with sham HBOT [relative risk (RR) 1.70, 95% confidence interval (CI) 1.11-2.61]. Moreover, there were significantly fewer additional surgical procedures required with HBOT (RR 1.60, 95% CI 1.03-2.50), and there was significantly less tissue necrosis (RR 1.70, 95% CI 1.11-2.61). In one of two American trials (n = 141) burn wounds healed significantly quicker with HBOT (P <0.005) than with routine burn care. A British trial (n = 48) compared HBOT with usual care. HBOT resulted in a significantly higher percentage of healthy graft area in split skin grafts (RR 3.50, 95% CI 1.35-9.11). In a Chinese trial (n = 145) HBOT did not significantly improve flap survival in patients with limb skin defects. HBOT, if readily available, appears effective for the management of acute, difficult to heal wound

Earthworms increase crop yield. But how? A meta-analysis.

ISEE 10

A comparison between the homocyclic aromatic metabolic pathways from plant-derived compounds by bacteria and fungi

Aromatic compounds derived from lignin are of great interest for renewable biotechnical applications. They can serve in many industries e.g. as biochemical building blocks for bioplastics or biofuels, or as antioxidants, flavor agents or food preservatives. In nature, lignin is degraded by microorganisms, which results in the release of homocyclic aromatic compounds. Homocyclic aromatic compounds can also be linked to polysaccharides, tannins and even found freely in plant biomass. As these compounds are often toxic to microbes already at low concentrations, they need to be degraded or converted to less toxic forms. Prior to ring cleavage, the plant- and lignin-derived aromatic compounds are converted to seven central ring-fission intermediates, i.e. catechol, protocatechuic acid, hydroxyquinol, hydroquinone, gentisic acid, gallic acid and pyrogallol through complex aromatic metabolic pathways and used as energy source in the tricarboxylic acid cycle. Over the decades, bacterial aromatic metabolism has been described in great detail. However, the studies on fungal aromatic pathways are scattered over different pathways and species, complicating a comprehensive view of fungal aromatic metabolism. In this review, we depicted the similarities and differences of the reported aromatic metabolic pathways in fungi and bacteria. Although both microorganisms share the main conversion routes, many alternative pathways are observed in fungi. Understanding the microbial aromatic metabolic pathways could lead to metabolic engineering for strain improvement and promote valorization of lignin and related aromatic compounds.Peer reviewe