Social Capital in Coordination Experiments: Risk, Trust and Position

Social capital theory is exemplary in attempting to integrate both individual and institutional perspectives in the study of governance, but interactions between the individual and institutional components remain underexplored and unspecified in many situations. We extend the theory from its focal attention on prisoners dilemma games to an important and understudied class of collective action problems of critical concern for governance— coordination tasks ranging from simple matching games to more complex tasks involving conflict (battle of the sexes) and assurance problems (stag hunt). Laboratory experiments provide a means of observing the impact of institutional influences (bridging and bonding network capital), individual predispositions (trust and risk aversion), and their interaction on the ability to coordinate in these settings. The results confirm that neither individual nor institutional components alone can explain coordination, and that interactions between these components must be understood in terms of the specific task context being studied

Debris Disks in the Scorpius-Centaurus OB Association Resolved by ALMA

We present a CO(2-1) and 1240 um continuum survey of 23 debris disks with spectral types B9-G1, observed at an angular resolution of 0.5-1 arcsec with the Atacama Large Millimeter/Submillimeter Array (ALMA). The sample was selected for large infrared excess and age ~10 Myr, to characterize the prevalence of molecular gas emission in young debris disks. We identify three CO-rich debris disks, plus two additional tentative (3-sigma) CO detections. Twenty disks were detected in the continuum at the >3-sigma level. For the 12 disks in the sample that are spatially resolved by our observations, we perform an independent analysis of the interferometric continuum visibilities to constrain the basic dust disk geometry, as well as a simultaneous analysis of the visibilities and broad-band spectral energy distribution to constrain the characteristic grain size and disk mass. The gas-rich debris disks exhibit preferentially larger outer radii in their dust disks, and a higher prevalence of characteristic grain sizes smaller than the blowout size. The gas-rich disks do not exhibit preferentially larger dust masses, contrary to expectations for a scenario in which a higher cometary destruction rate would be expected to result in a larger mass of both CO and dust. The three debris disks in our sample with strong CO detections are all around A stars: the conditions in disks around intermediate-mass stars appear to be the most conducive to the survival or formation of CO.Comment: 16 pages, 6 figures, accepted for publication in Ap

Mobilization, Strategy, and Global Apparel Production Networks: Systemic Advantages for Student Antisweatshop Activism

The U.S. antisweatshop movement is a major branch of Global North labor rights activism. We focus on the movement’s college student sector, which has been active and moderately effective since its 1997 birth. Using principles from social movement theory and global political economy, we examine (1) these student labor rights groups’ campus context, (2) global production networks (GPNs), and (3) how campus context and GPNs intersect to facilitate student antisweatshop activity and effectiveness in ways distinct from the non-campus U.S. movement. U.S. college campuses are places of pre-existing collective identity and dense interaction, facilitating antisweatshop mobilization. Collegiate apparel GPNs that source from the Global South contain both the student sector’s largest grievance and an opportunity structure of power relations that this sector seeks to engage. An on-campus movement opportunity also exists: a college administration which is beholden and accessible to students and is simultaneously a gatekeeper in licensed collegiate apparel GPNs – a spatially commensurate point of strategic leverage for a student antisweatshop group as it coordinates with production workers and their local allies. Thus, the student sector possesses certain advantages within a field of power relations permeating the larger network linking it to administrations and firms. Recognizing these distinct advantages and the synergy among them should usefully inform student antisweatshop activists and their allies as they mobilize support and formulate strategies

Mobilization, Strategy, and Global Apparel Production Networks: Systemic Advantages for Student Antisweatshop Activism

The U.S. antisweatshop movement is a major branch of Global North labor rights activism. We focus on the movement’s college student sector, which has been active and moderately effective since its 1997 birth. Using principles from social movement theory and global political economy, we examine (1) these student labor rights groups’ campus context, (2) global production networks (GPNs), and (3) how campus context and GPNs intersect to facilitate student antisweatshop activity and effectiveness in ways distinct from the non-campus U.S. movement. U.S. college campuses are places of pre-existing collective identity and dense interaction, facilitating antisweatshop mobilization. Collegiate apparel GPNs that source from the Global South contain both the student sector’s largest grievance and an opportunity structure of power relations that this sector seeks to engage. An on-campus movement opportunity also exists: a college administration which is beholden and accessible to students and is simultaneously a gatekeeper in licensed collegiate apparel GPNs – a spatially commensurate point of strategic leverage for a student antisweatshop group as it coordinates with production workers and their local allies. Thus, the student sector possesses certain advantages within a field of power relations permeating the larger network linking it to administrations and firms. Recognizing these distinct advantages and the synergy among them should usefully inform student antisweatshop activists and their allies as they mobilize support and formulate strategies

ALMA Observations of the Orion Proplyds

We present ALMA observations of protoplanetary disks ("proplyds") in the Orion Nebula Cluster. We imaged 5 individual fields at 856um containing 22 HST-identified proplyds and detected 21 of them. Eight of those disks were detected for the first time at submillimeter wavelengths, including the most prominent, well-known proplyd in the entire Orion Nebula, 114-426. Thermal dust emission in excess of any free-free component was measured in all but one of the detected disks, and ranged between 1-163 mJy, with resulting disk masses of 0.3-79 Mjup. An additional 26 stars with no prior evidence of associated disks in HST observations were also imaged within the 5 fields, but only 2 were detected. The disk mass upper limits for the undetected targets, which include OB stars, theta1Ori C and theta1Ori F, range from 0.1-0.6 Mjup. Combining these ALMA data with previous SMA observations, we find a lack of massive (>3 Mjup) disks in the extreme-UV dominated region of Orion, within 0.03 pc of O-star theta1Ori C. At larger separations from theta1Ori C, in the far-UV dominated region, there is a wide range of disk masses, similar to what is found in low-mass star forming regions. Taken together, these results suggest that a rapid dissipation of disk masses likely inhibits potential planet formation in the extreme-UV dominated regions of OB associations, but leaves disks in the far-UV dominated regions relatively unaffected.Comment: ApJ, in pres

Oolemmal proteomics – identification of highly abundant heat shock proteins and molecular chaperones in the mature mouse egg and their localization on the plasma membrane

BACKGROUND: The mature mouse egg contains the full complement of maternal proteins required for fertilization, the transition to zygotic transcription, and the beginning stages of embryogenesis. Many of these proteins remain to be characterized, therefore in this study we have identified highly abundant egg proteins using a proteomic approach and found that several of these proteins also appear to localize to the egg surface. Characterization of such molecules will provide important insight into the cellular events of fertilization and early development. METHODS: In order to identify some of the more abundant egg proteins, whole egg extracts were resolved on coomassie-stained two-dimensional (2D) PAGE gels. Several highly abundant protein spots were cored and microsequenced by tandem mass spectrometry (TMS), and determined to be molecular chaperone proteins. Concurrent experiments were performed to identify oolemmal proteins using 2D avidin blotting. Proteins spots that appeared to be surface labeled by biotinylation were correlated with the initial coomassie-stained reference gel. Surprisingly, some of the surface labelled proteins corresponded to those abundant chaperone proteins previously identified. To confirm whether these molecules are accumulating at the oolemmal surface in eggs, we performed immunofluoresence on live, zona-free eggs using antibodies to HSP70, HSP90, GRP94, GRP78, calreticulin and calnexin. RESULTS: The putative surface-labeled proteins identified by biotinylation included the molecular chaperones HSP70 (MW 70 KDa, pI 5.5), HSP90a (MW 85 KDa, pI 4.9), GRP94 (MW 92 KDa, pI 4.7), GRP78 (MW 72 KDa, pI 5.0), Oxygen regulated protein 150 (ORP150; MW 111 KDa, pI 5.1), Calreticulin (MW 48 KDa, pI 4.3), Calnexin (MW 65 KDa, pI 4.5), and Protein disulfide isomerase (PDI; MW 57 KDa, pI 4.8). Immunofluoresence results showed that antibodies to HSP90, GRP94, GRP78 and calreticulin were reactive with oolemmal proteins. We were unable to confirm surface localization of HSP70 or calnexin by this method. CONCLUSIONS: We report here the identification of nine highly abundant molecular chaperones in the mouse egg proteome. In addition, we present preliminary data suggesting that these molecules localize to the oolemma of the mature mouse egg

Collaborative Action Research for Middle Grades Improvement

Technology’s rapid evolution applies constant pressure to educational organizations, suggesting a need to continually re-envision schools for the digital age. Yet educators often struggle to understand the growing chasm between students’ out-of-school and in-school technology lives. This gap is particularly noticeable during the middle grades years, when home technology use increases dramatically. The purpose of this research was to examine the experiences of teachers and students engaged in collaborative action research for middle school improvement in technology-rich settings. We begin by outlining our theoretical framework, emphasizing Fletcher’s Ladder of Student Involvement. We then describe our case-study design and methods. Findings are organized by action research components and a discussion of key themes follows. Finally, we consider the implications of this stud

Sensitive Flow Cytometric Analysis Reveals a Novel Type of Parent-of-Origin Effect in the Mouse Genome

AbstractThe discovery of classic parental imprinting came, at least in part, from the analysis of transgene expression in mice [1]. It was noticed that some transgenes were only expressed following paternal transmission [2–4] and that others sometimes showed differential patterns of methylation depending on the parent of origin [5, 6]. Here, we present evidence of a novel and more subtle form of parental imprinting by taking advantage of the highly sensitive detection of murine transgene expression afforded by flow cytometry. We have produced nine lines of transgenic mice carrying a GFP reporter linked to the human α-globin promoter and enhancer elements, which direct expression to erythroid cells. A high proportion of transgenic lines, four of the nine, display significantly lower levels of expression following maternal transmission. Both the percentage of expressing cells and the mean fluorescence in expressing cells are between 10% and 30% lower following maternal transmission. These effects are reversible upon passage through the opposite germline. This finding raises the possibility that differences in the epigenetic state of the maternal and paternal chromosomes in adult somatic cells are more widespread than was previously thought