Behavioural Development Economics: Lessons from field labs in the developing world

Explanations of poverty, growth and development more generally depend on the assumptions made about individual preferences and the willingness to engage in strategic behaviour. Economic experiments, especially those conducted in the field, have begun to paint a picture of economic agents in developing communities that is at some variance from the traditional portrait. We review this growing literature with an eye towards preference-related experiments conducted in the field. We rely on these studies, in addition to our own experiences in the field, to offer lessons on what development economists might learn from experiments. We conclude by sharing our thoughts on how to conduct experiments in the field, and then offer a few ideas for future research.

Mutual Monitoring in Teams: Theory and Experimental Evidence on the Importance of Reciprocity

Monitoring by peers is often an effective means of attenuating incentive problems. Most explanations of the efficacy of mutual monitoring rely either on small group size or on a version of the Folk theorem with repeated interactions which requires reasonably accurate public information concerning the behavior of each player. We provide a model of team production in which the effectiveness of mutual monitoring depends not on these factors, but rather on strong reciprocity: the willingness of some team members to engage in the costly punishment of shirkers. This alternative does not require small group size or public signals. An experimental public goods game provides evidence for the behavioral relevance of strong reciprocity in teams.

Grid Cells Form a Global Representation of Connected Environments.

The firing patterns of grid cells in medial entorhinal cortex (mEC) and associated brain areas form triangular arrays that tessellate the environment [1, 2] and maintain constant spatial offsets to each other between environments [3, 4]. These cells are thought to provide an efficient metric for navigation in large-scale space [5-8]. However, an accurate and universal metric requires grid cell firing patterns to uniformly cover the space to be navigated, in contrast to recent demonstrations that environmental features such as boundaries can distort [9-11] and fragment [12] grid patterns. To establish whether grid firing is determined by local environmental cues, or provides a coherent global representation, we recorded mEC grid cells in rats foraging in an environment containing two perceptually identical compartments connected via a corridor. During initial exposures to the multicompartment environment, grid firing patterns were dominated by local environmental cues, replicating between the two compartments. However, with prolonged experience, grid cell firing patterns formed a single, continuous representation that spanned both compartments. Thus, we provide the first evidence that in a complex environment, grid cell firing can form the coherent global pattern necessary for them to act as a metric capable of supporting large-scale spatial navigation

Novel Approach to Managing Technological Entrepreneurship Using a Model-Based Systems Approach to Develop Low Cost Earth Orbiting Satellites

The ability to send low cost satellites into space has changed the satellite industry and vastly opened up the use of satellites to transform data into information for individuals, organizations, commercial companies, and governments. This information can be corroborated with other sources of data to evaluate the availability of precious resources, e.g., potable water, agriculture; to forecast upcoming famines or diseases; and to perform mapping, communications, and competitive analyses. The cost of owning a satellite is less than 100,000(usingcommercialparts)to1,000 (built by school kids). Launch costs are tens of thousands of dollars, which can be eliminated through subsidies. Compare these costs to 200millionto1 billion costs for similar functionality, higher performance and greater durability-an interesting trade space that favors multiple low cost flights versus significantly higher costs for permanent satellites for an increasing number of applications. The challenge is to form and manage a development team of unskilled professionals, high school students, or university students to meet deadlines and flight-standards. These team members are likely highly motivated and unskilled. This paper describes the technical management strategy and techniques used to develop the 10 cm, 6-sided CubeSats

Risk-Based Consumption Advice for Farmed Atlantic and Wild Pacific Salmon Contaminated with Dioxins and Dioxin-like Compounds

We reported recently that several organic contaminants occurred at elevated concentrations in farmed Atlantic salmon compared with concentrations of the same contaminants in wild Pacific salmon [Hites et al. Science 303:226–229 (2004)]. We also found that polychlorinated biphenyls (PCBs), toxaphene, dieldrin, dioxins, and polybrominated diphenyl ethers occurred at higher concentrations in European farm-raised salmon than in farmed salmon from North and South America. Health risks (based on a quantitative cancer risk assessment) associated with consumption of farmed salmon contaminated with PCBs, toxaphene, and dieldrin were higher than risks associated with exposure to the same contaminants in wild salmon. Here we present information on cancer and noncancer health risks of exposure to dioxins in farmed and wild salmon. The analysis is based on a tolerable intake level for dioxin-like compounds established by the World Health Organization and on risk estimates for human exposure to dioxins developed by the U.S. Environmental Protection Agency. Consumption of farmed salmon at relatively low frequencies results in elevated exposure to dioxins and dioxin-like compounds with commensurate elevation in estimates of health risk

Grid cells form a global representation of connected environments

The firing patterns of grid cells in medial entorhinal cortex (mEC) and associated brain areas form triangular arrays that tessellate the environment [1, 2] and maintain constant spatial offsets to each other between environments [3, 4]. These cells are thought to provide an efficient metric for navigation in large-scale space [5, 6, 7, 8]. However, an accurate and universal metric requires grid cell firing patterns to uniformly cover the space to be navigated, in contrast to recent demonstrations that environmental features such as boundaries can distort [9, 10, 11] and fragment [12] grid patterns. To establish whether grid firing is determined by local environmental cues, or provides a coherent global representation, we recorded mEC grid cells in rats foraging in an environment containing two perceptually identical compartments connected via a corridor. During initial exposures to the multicompartment environment, grid firing patterns were dominated by local environmental cues, replicating between the two compartments. However, with prolonged experience, grid cell firing patterns formed a single, continuous representation that spanned both compartments. Thus, we provide the first evidence that in a complex environment, grid cell firing can form the coherent global pattern necessary for them to act as a metric capable of supporting large-scale spatial navigation

Detecting microRNA activity from gene expression data

<p>Abstract</p> <p>Background</p> <p>MicroRNAs (miRNAs) are non-coding RNAs that regulate gene expression by binding to the messenger RNA (mRNA) of protein coding genes. They control gene expression by either inhibiting translation or inducing mRNA degradation. A number of computational techniques have been developed to identify the targets of miRNAs. In this study we used predicted miRNA-gene interactions to analyse mRNA gene expression microarray data to predict miRNAs associated with particular diseases or conditions.</p> <p>Results</p> <p>Here we combine correspondence analysis, between group analysis and co-inertia analysis (CIA) to determine which miRNAs are associated with differences in gene expression levels in microarray data sets. Using a database of miRNA target predictions from TargetScan, TargetScanS, PicTar4way PicTar5way, and miRanda and combining these data with gene expression levels from sets of microarrays, this method produces a ranked list of miRNAs associated with a specified split in samples. We applied this to three different microarray datasets, a papillary thyroid carcinoma dataset, an in-house dataset of lipopolysaccharide treated mouse macrophages, and a multi-tissue dataset. In each case we were able to identified miRNAs of biological importance.</p> <p>Conclusions</p> <p>We describe a technique to integrate gene expression data and miRNA target predictions from multiple sources.</p

Impaired degranulation but enhanced cytokine production after FcɛRI stimulation of diacylglycerol kinase ζ–deficient mast cells

Calcium and diacylglycerol are critical second messengers that together effect mast cell degranulation after allergen cross-linking of immunoglobulin (Ig)E-bound FcɛRI. Diacylglycerol kinase (DGK)ζ is a negative regulator of diacylglycerol-dependent signaling that acts by converting diacylglycerol to phosphatidic acid. We reported previously that DGKζ−/− mice have enhanced in vivo T cell function. Here, we demonstrate that these mice have diminished in vivo mast cell function, as revealed by impaired local anaphylactic responses. Concordantly, DGKζ−/− bone marrow–derived mast cells (BMMCs) demonstrate impaired degranulation after FcɛRI cross-linking, associated with diminished phospholipase Cγ activity, calcium flux, and protein kinase C–βII membrane recruitment. In contrast, Ras-Erk signals and interleukin-6 production are enhanced, both during IgE sensitization and after antigen cross-linking of FcɛRI. Our data demonstrate dissociation between cytokine production and degranulation in mast cells and reveal the importance of DGK activity during IgE sensitization for proper attenuation of FcɛRI signals