Women's Professional Identity Formation in the Free/Open Source Software Community

We examine the formation of women’s professional identity in a particular type of male-dominated domain, the free and open source software development communities, and more broadly in information technology. Through an ethnographic analysis of interviews and online forums discussions, we find that women experience two types of discrepancies or gaps that constitute obstacles in the process of identity formation: an image gap and an identity gap. We show the strategies employed by women as they attempt to bridge these gaps; we also find that some of these strategies, while tackling one gap, may also deepen the other.Gender; Identity Formation; Self-presentation

Testing for Exceptional Bulls and Bears: a Non-Parametric Perspective

This paper investigates exceptional phases of stock market cycles. Defined in Pagan and Sossounov (2003) as unusual, they are detected as outliers in the historical distribution. Moreover, this study completes the growing literature on stock market bulls and bears in several aspects. First,it extends the description of financial cy- cles by going beyond solely the duration feature. Second, a new strategy to test for single and multiple outliers is presented. Based on this procedure, the exceptional bulls and bears that occurred since 1973 are detected. A complementary analysis deals with the specific cross-country patterns of the current sub-prime crisis. Our results are mixed, in the sense that they do not support the idea that the ongoing bear is exceptional for all the analyzed countries. Moreover, the results indicate that the stock market indices are still far away from the thresholds beyond which the current bear phase will become exceptional worldwide.monetary economics ;

Beyond Orality and Literacy: Letters and Organizational Communication

We draw on communication theories to study organizational communication from a literacy perspective. We suggest that the current debate over the capability of new media to foster the sharing and development of ideas and allow the expression of emotions, which presupposes face-to-face communication as the ideal form of communication, disappears once we switch the focus from the medium to the modality – written versus oral communication. An analysis of personal and organizational letters illustrates the role played by written communication throughout human history, in exchanging ideas and supporting emotionalOrality and Literacy; Online Interactions; Communicative Practices; Letters; Organizational Communication

Letters and Scientific Communities

We enter the debate about the possibility of collaboration and of rich exchanges among physically distant individuals by offering a literacy perspective on communication to show how the dimensions of writing enable the development of scientific communities. We illustrate this perspective with an analysis of the correspondences of one philosopher and one scientist – Descartes and Emilie du Chatelet, as well as with a description of one of the most prominent communities of scientists and philosophers in Europe, the Republic of Letters. Our findings show that writing is essential for the expression and exchange of ideas, abstractions, complex thoughts, demonstrations, arguments – in sum, for the entire scientific enterprise. We discuss the implications of the literacy perspective and of our findings for the current understanding of online intellectual communities.Orality and Literacy; Scientific Communities; Online Communities; Letters; Organizational Communication

Kinetics of spin coherence of electrons in an undoped semiconductor quantum well

We study the kinetics of spin coherence of optically excited electrons in an undoped insulating ZnSe/Zn$_{1-x}$Cd$_x$Se quantum well under moderate magnetic fields in the Voigt configuration. After clarifying the optical coherence and the spin coherence, we build the kinetic Bloch equations and calculate dephasing and relaxation kinetics of laser pulse excited plasma due to statically screened Coulomb scattering and electron hole spin exchange. We find that the Coulomb scattering can not cause the spin dephasing, and that the electron-hole spin exchange is the main mechanism of the spin decoherence. Moreover the beat frequency in the Faraday rotation angle is determined mainly by the Zeeman splitting, red shifted by the Coulomb scattering and the electron hole spin exchange. Our numerical results are in agreement with experiment findings. A possible scenario for the contribution of electron-hole spin exchange to the spin dephasing of the $n$-doped material is also proposed.Comment: 12 pages, RevTex, 11 figures, scheduled to publish in PRB Jan. 15, 200

On the Electrostatic Calculation of the ESCA Chemical Shifts

The electrostatic formula for the calculation of the ESCA chemical shifts is developed within the framework of the INDO approximation and by using Taylor expansion of the 1/r operator. The INDO wavefunctions were employed for the calculation of the ls electron binding energy changes in some characteristic organic molecules. It was shown that the electrostatic formula based on the point charge approximation workls quite well and that the inclusion of the polarized charge cloud does not improve the results to any significant extent

Density Functional Study of the Adsorption of Propene on Mixed Gold-Silver Clusters, AunAgm: Propensity Rules for Binding

We use density functional theory to investigate the binding of propene to small mixed Au–Ag clusters, in the gas phase. We have found that the rules proposed by us for propene binding to Au and Ag clusters, also work for binding to mixed Au–Ag clusters. The rules state that propene binds to those sites on the edge of the cluster where the equal density plots of the LUMO of the naked cluster protrude into the vacuum. Furthermore, the desorption energy of propene correlate with the LUMO energy: the lower the LUMO energy, the stronger the propene bond. We have also found an additional rule that is specific to mixed clusters. We call active the atoms on which the LUMO of the naked cluster protrude in the vacuum, and inactive those for which such protrusions do not exist. To define the rules we use the following notation: A is an active site to which propene is bound B is another active site, and C is an inactive site. If the atom in C(Ag or Au) is replaced with another atom (Au or Ag) propene desorption energy changes very little. If we replace the atom B with a more electronegative atom (i.e., we replace Ag by Au) the propene bond to A becomes stronger. If we replace the atom B with a less electronegative atom (i.e., we replace Au by Ag) the propene bond to A becomes weaker

On the Electrostatic Calculation of the ESCA Chemical Shifts

The electrostatic formula for the calculation of the ESCA chemical shifts is developed within the framework of the INDO approximation and by using Taylor expansion of the 1/r operator. The INDO wavefunctions were employed for the calculation of the ls electron binding energy changes in some characteristic organic molecules. It was shown that the electrostatic formula based on the point charge approximation workls quite well and that the inclusion of the polarized charge cloud does not improve the results to any significant extent