Performance Spillovers and Social Network in the Workplace: Evidence from Rural and Urban Weavers in a Chinese Textile Firm

We provide some of the first rigorous evidence on performance spillovers and social network in the workplace. The data we use are rather extraordinary – weekly data for rejection rates (proportion of defective output) for all weavers in a firm during a 12 months (April 2003-March 2004) period, more than 10,000 observations. Our fixed effect estimates first point to significant spillovers of performance from high-ability weavers to low-ability weavers. On the other hand, we find no evidence for performance spillovers from low-ability to high-ability weavers. The findings are consistent with the knowledge sharing hypothesis that low-ability workers learn from high-ability workers but not vice versa. Second, by exploiting the well-documented fact that an exogenously-formed sharp divide between urban workers and rural migrant workers exists in firms in Chinese cities, we find that performance spillovers/knowledge sharing take place only within the confines of social network. Specifically rural low-ability weavers are found to improve their performance as their high-ability teammates (who are also rural migrants) improve their performance while they do not benefit from performance improvement of their high-ability teammates who are urban residents. Such heterogeneous performance interdependence of workers within the same team suggests that our evidence for performance spillovers is less likely to be a result of team specific demand shocks that generate spurious performance interdependence of all team members.knowledge sharing, performance spillovers, social network

Peer Effects, Social Networks, and Intergroup Competition in the Workplace

Using weekly data for defect rates (proportion of defective output) for all weavers in a Chinese textile firm during a 12 months (April 2003 - March 2004) period, we provide some of the first rigorous evidence on the presence and nature of peer effects in the manufacturing workplace. First, a worker is found to put in more effort and improve her performance when she is working with more able teammates. Second, by exploiting the well-documented fact that an exogenouslyformed strong divide between urban resident workers and rural migrant workers exists in firms in Chinese cities, we provide novel evidence on the interplay between social networks (urban resident group and rural migrant group) and peer effects. Specifically, we find that a worker puts in more effort when she is working with more able outgroup teammates but not when working with more able ingroup teammates, pointing to intergroup competition as a powerful source of the peer effects. Such peer effects across the social network, combined with the presence of incentive to outperform teammates at this firm, are largely consistent with recent experimental evidence on the important role that group identities play in facilitating altruistic behaviors.peer effects in the workplace; social networks; intergroup competition

Competition, Group Identity, and Social Networks in the Workplace: Evidence from a Chinese Textile Firm

Using data on team assignment and weekly output for all weavers in an urban Chinese textile firm between April 2003 and March 2004, this paper studies a) how randomly assigned teammates affect an individual worker's behavior under a tournament-style incentive scheme, and b) how such effects interact with exogenously formed social networks in the manufacturing workplace. First, we find that a worker's performance improves when the average ability of her teammates increases. Second, we exploit the exogenous variations in workers' origins in the presence of the well-documented social divide between urban resident workers and rural migrant workers in large urban Chinese firms, and show that the coworker effects are only present if the teammates are of a different origin. In other words, workers do not act on pecuniary incentives to outperform teammates who are from the same social network. Our results point to the important role of group identities in overcoming self-interests and facilitating altruistic behavior.coworker effects in the workplace, social networks, intergroup competition

Performance spillovers and social network in the workplace: evidence from rural and urban weavers in a Chinese textile firm

We provide some of the first rigorous evidence on performance spillovers and social network in the workplace. The data we use are rather extraordinary - weekly data for rejection rates (proportion of defective output) for all weavers in a firm during a 12 months (April 2003-March 2004) period, more than 10,000 observations. Our fixed effect estimates first point to significant spillovers of performance from high-ability weavers to low-ability weavers. On the other hand, we find no evidence for performance spillovers from low-ability to high-ability weavers. The findings are consistent with the knowledge sharing hypothesis that low-ability workers learn from high-ability workers but not vice versa. Second, by exploiting the well-documented fact that an exogenously-formed sharp divide between urban workers and rural migrant workers exists in firms in Chinese cities, we find that performance spillovers/knowledge sharing take place only within the confines of social network. Specifically rural low-ability weavers are found to improve their performance as their high-ability teammates (who are also rural migrants) improve their performance while they do not benefit from performance improvement of their high-ability teammates who are urban residents. Such heterogeneous performance interdependence of workers within the same team suggests that our evidence for performance spillovers is less likely to be a result of team specific demand shocks that generate spurious performance interdependence of all team members

Competition, group identity, and social networks in the workplace: Evidence from a Chinese textile firm

Using data on team assignment and weekly output for all weavers in an urban Chinese textile firm between April 2003 and March 2004, this paper studies a) how randomly assigned teammates affect an individual worker's behavior under a tournament-style incentive scheme, and b) how such effects interact with exogenously formed social networks in the manufacturing workplace. First, we find that a worker's performance improves when the average ability of her teammates increases. Second, we exploit the exogenous variations in workers' origins in the presence of the well-documented social divide between urban resident workers and rural migrant workers in large urban Chinese firms, and show that the coworker effects are only present if the teammates are of a different origin. In other words, workers do not act on pecuniary incentives to outperform teammates who are from the same social network. Our results point to the important role of group identities in overcoming self-interests and facilitating altruistic behavior

Metaphorical Action Retrospectively but Not Prospectively Alters Emotional Judgment

Metaphorical association between vertical space and emotional valence is activated by bodily movement toward the corresponding space. Upward or downward manual movement “following” observation of emotional images is reported to alter the perceived valence as more positive or negative. This study aimed to clarify this retrospective emotional modulation. Experiment 1 investigated the effects of temporal order of emotional stimuli and manual movements. Participants performed upward, downward, or horizontal manual movements immediately before or after observation of emotional images; they then rated the valence of the image. The images were rated as more negative in downward- than in horizontal-movement conditions only when the movements followed the image observation. Upward movement showed no effect. Experiment 2 examined the effects of temporal proximity between images, movements, and ratings. The results showed that a 2-s interval either between image and movement or movement and rating nullified the retrospective effect. Bodily movement that corresponds to space–valence metaphor retrospectively, but not prospectively, alters the perceived valence of emotional stimuli. This effect requires temporal proximity between emotional stimulus, the subsequent movement, and rating of the stimulus. With respect to the lack of effect of upward–positive correspondence, anisotropy in effects of movement direction is discussed

Corotational Instability of Inertial-Acoustic Modes in Black Hole Accretion Discs and Quasi-Periodic Oscillations

We study the global stability of non-axisymmetric p-modes (also called inertial-acoustic modes) trapped in the inner-most regions of accretion discs around black holes. We show that the lowest-order (highest-frequency) p-modes, with frequencies $\omega=(0.5-0.7) m\Omega_{\rm ISCO}$, can be overstable due to general relativistic effects, according to which the radial epicyclic frequency is a non-monotonic function of radius near the black hole. The mode is trapped inside the corotation resonance radius and carries a negative energy. The mode growth arises primarily from wave absorption at the corotation resonance, and the sign of the wave absorption depends on the gradient of the disc vortensity. When the mode frequency is sufficiently high, such that the slope of the vortensity is positive at corotation positive wave energy is absorbed at the resonance, leading to the growth of mode amplitude. We also study how the rapid radial inflow at the inner edge of the disc affects the mode trapping and growth. Our analysis of the behavior of the fluid perturbations in the transonic flow near the ISCO indicates that, while the inflow tends to damp the mode, the damping effect is sufficiently small under some conditions so that net mode growth can still be achieved. We further clarify the role of the Rossby wave instability and show that it does not operate for black hole accretion discs with smooth-varying vortensity profiles. Overstable non-axisymmetric p-modes driven by the corotational instability provide a plausible explanation for the high-frequency (> 100 Hz) quasi-periodic oscillations (HFQPOs) observed from a number of black-hole X-ray binaries in the very high state. The absence of HFQPOs in the soft (thermal) state may result from mode damping due to the radial infall at the ISCO.Comment: 19 pages, 11 figures, MNRAS in pres

Interaction of young stellar object jets with their accretion disk

I reexamine recent observations of velocity profiles across jets blown by young stellar objects, and argue that the observations do not support the interpretation of jets rotating around their symmetry axes. Instead, I propose that the interaction of the jets with a twisted-tilted (wrapped) accretion disk can form the observed asymmetry in the jets' line of sight velocity profiles. The proposed scenario is based on two plausible assumptions. (1) There is an inclination between the jet and the outer parts of the disk; the jet is perpendicular to the inner part of the disk; Namely, there is a twisted-tilted (wrapped) disk. (2) The disk-jet interaction slows down the jet as the jet entrains mass from the disk, with larger decelaration of jet segments closer to the tilted disk. The proposed scenario can account for the basic properties of the observed velocity profiles, while having the advantage that there is no need to refer to any magnetic jet launching model, and there is no need to invoke jet rotation with a huge amount of angular momentum.Comment: Astronomy and Astrophysics, in press (contains an appendix which is not in A&A

Super-Reflection in Fluid Discs: Corotation Amplifier, Corotation Resonance, Rossby Waves, and Overstable Modes

In differentially rotating discs with no self-gravity, density waves cannot propagate around the corotation, where the wave pattern rotation speed equals the fluid rotation rate. Waves incident upon the corotation barrier may be super-reflected (commonly referred to as corotation amplifier), but the reflection can be strongly affected by wave absorptions at the corotation resonance/singularity. The sign of the absorption is related to the Rossby wave zone very near the corotation radius. We derive the explicit expressions for the complex reflection and transmission coefficients, taking into account wave absorption at the corotation resonance. We show that for generic discs, this absorption plays a much more important role than wave transmission across the corotation barrier. Depending on the sign of the gradient of the specific vorticity of the disc the corotation resonance can either enhance or diminish the super-reflectivity, and this can be understood in terms of the location of the Rossby wave zone relative to the corotation radius. Our results provide the explicit conditions (in terms of disc thickness, rotation profile and specific vorticity gradient) for which super-reflection can be achieved. Global overstable disc modes may be possible for discs with super-reflection at the corotation barrier.Comment: 16 pages, 5 figures, MNRAS in pres

Gene targeting for O -methyltransferase genes, mycE and mycF , on the chromosome of Micromonospora griseorubida producing mycinamicin with a disruption cassette containing the bacteriophage φC31 attB attachment site

Mycinamicin, a 16-membered macrolide antibiotic produced by Micromonospora griseorubida , comprises a macrolactone and two deoxysugars: desosamine and mycinose. Mycinose is synthesized through two modification steps: the methylation of 6-deoxyallose in mycinamicin VI and of javose in mycinamicin III. To confirm the role of mycE and mycF genes in mycinamicin biosynthesis in M. griseorubida , disruption mutants of mycE and mycF were constructed by disruption plasmids containing attB in the disruption cassette FRT -neo-oriT- FRT -attB for the integration of φC31-derivative vector plasmids; the disruption mutants were complemented through the integration of pSET152 derivatives containing intact mycE or mycF into the artificially inserted attB site. These disruption mutants did not produce mycinamicin II, but mainly accumulated mycinamicins VI and III, indicating that MycE and MycF methylated the C2″-OH group of 6-deoxyallose in mycinamicin VI and the C3″-OH group of C2″-methylated 6-deoxyallose in mycinamicin III, respectively. The complemented strains of mycE and mycF recovered the mycinamicin II productivity.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/79258/1/j.1574-6968.2010.01899.x.pd