Temporally resolved laser induced plasma diagnostics of single crystal silicon - effects of ambient pressure

Laser-Induced Breakdown Spectroscopy of silicon was performed using a nanosecond pulsed frequency doubled Nd:YAG (532 nm) laser. The temporal evolution of the laser ablation plumes in air at atmospheric pressure and at an ambient pressure of ∼10−5 mbar is presented. Electron densities were determined from the Stark broadening of the Si (I) 288.16 nm emission line. Electron densities in the range of 6.91×1017 to 1.29×1019 cm−3 at atmospheric pressure and 1.68×1017 to 3.02×1019 cm−3 under vacuum were observed. Electron excitation temperatures were obtained from the line to continuum ratios and yielded temperatures in the range 7600–18,200 K at atmospheric pressure, and 8020–18,200 K under vacuum. The plasma morphology is also characterized with respect to time in both pressure regimes

On-the-Job Search and Precautionary Savings: Theory and Empirics of Earnings and Wealth Inequality. Version of January 13, 2006

In this paper, I develop and estimate a model of the labor market that can account for both the inequality in earnings and the much larger inequality in wealth observed in the data. I show that an equilibrium model of on-the-job search, augmented to account for saving decisions of workers, provides a direct and intuitive link between the empirical earnings and wealth distributions. The mechanism that generates the high degree of wealth inequality in the model is the dynamic of the ``wage ladder'' resulting from the search process. There is an important asymmetry between the incremental wage increases generated by on-the-job search (climbing the ladder) and the drop in income associated with job loss (falling off the ladder). This feature of the model generates differential savings behavior at different points in the earnings distribution. The wage growth expected by low wage workers, combined with the fact that their earnings are not much higher than unemployment benefits, causes them to dis-save. As a worker's wage increases, the incentive to save increases: the potential for wage growth declines and it becomes increasingly important to insure against the large income reduction associated with job loss. The fact that high wage and low wage workers have such different savings behavior generates an equilibrium wealth distribution that is much more unequal than the equilibrium wage distribution. I estimate the structural parameters of the model by simulation-based methods using the 1979 youth cohort of the NLSY. The estimates indicate that the micro-level search and savings behavior---estimated from the dynamics of individuals' labor market histories and wealth accumulation decisions---aggregates to replicate the cross-sectional inequality in earnings and wealth for this cohort

Revisiting Lancaster : more things that every social work student should know

It has been argued previously that social work students need to understand what is known about those people who sexually offend and abuse in order to provide adequate services to both victims/survivors and offenders/abusers. This article explores how engaging with a highly emotional topic can be undertaken in ways that make links with other forms of knowledge within social work education programmes. It also presents techniques based on the experience of teaching and learning about sexual offending that have been useful, allowing students to think and talk about issues that are often obscured by emotion, rhetoric and claims for trut

The Four Cs of Promising Practices in Community Colleges

To address the achievement or opportunity gap of underrepresented populations in community colleges, this qualitative field methods study investigated five California community college programs that have demonstrated progress in improving (or show significant potential to improve) student achievement. This research found that promising practices have several conceptual conditions in common-cohesion, connection, cooperation, and consistency-referred to as the Four Cs. Although many of the key components that contribute to the development of promising practices in community college programs are unique to their specific contexts, the presence of these more general Four Cs may be transferable to other community college sites because they can be cultivated in different contexts while respecting the idiosyncrasies of particular community colleges. © 2014 Copyright Taylor and Francis Group, LLC

Demonstration that a lectin-like receptor (gp90MEL) directly mediates adhesion of lymphocytes to high endothelial venules of lymph nodes.

Lymphocyte migration from the blood into most secondary lymphoid organs is initiated by a highly selective adhesive interaction with the endothelium of specialized blood vessels known as high endothelial venules (HEV). The propensity of lymphocytes to migrate to particular lymphoid organs is known as lymphocyte homing, and the receptors on lymphocytes that dictate interactions with HEV at particular anatomical sites are designated "homing receptors". Based upon antibody blockade experiments and cell-type distribution studies, a prominent candidate for the peripheral lymph node homing receptor in mouse is the approximately 90-kD cell surface glycoprotein (gp90MEL) recognized by the monoclonal antibody MEL-14. Previous work, including sequencing of a cDNA encoding for this molecule, supports the possibility that gp90MEL is a calcium-dependent lectin-like receptor. Here, we show that immunoaffinity-purified gp90MEL interacts in a sugar-inhibitable manner with sites on peripheral lymph node HEV and prevents attachment of lymphocytes. Lymphocyte attachment to HEV in Peyer's patches, a gut-associated lymphoid organ, is not affected by gp90MEL. The results demonstrate that gp90MEL, as a lectin-like receptor, directly bridges lymphocytes to the endothelium

The hybrid and dualistic identity of full-time non-tenure-track faculty

Colleges and universities rely on full-time non-tenure-track (FTNT) faculty to achieve their teaching, research, and service missions. These faculty are deemed both symptomatic of and partly responsible for academe's shortcomings. The ascriptions, however, are made with little attention to the faculty themselves or to their consequences for FTNT faculty. Through analysis of interview data of university faculty, the authors present and explain FTNT faculty self-representations of professional and occupational identity. Assumptions drawn from institutional and professional theory contextualize the research, and narrative analysis infuses the application of the framework of cultural identity theory. These FTNT faculty are found to possess hybrid and dualistic identities. Their work and roles are a hybrid and contain some elements of a profession and some of a "job." Their identity is dualistic because as teachers, they express satisfaction, whereas as members of the professoriate, they articulate restricted self-determination and self-esteem. This troubled and indistinct view of self-as-professional is problematic both for FTNT faculty as they go about their daily work and for their institutions, which are in no small part responsible for the uncertain conditions and identities of FTNT faculty. © 2011 SAGE Publications

Activation of electroneutral K flux in Amphiuma red blood cells by N-ethylmaleimide. Distinction between K/H exchange and KCl cotransport.

Exposure of Amphiuma red blood cells to millimolar concentrations of N-ethylmaleimide (NEM) resulted in net K loss. In order to determine whether net K loss was conductive or was by electroneutral K/H exchange or KCl cotransport, studies were performed evaluating K flux in terms of the thermodynamic forces to which K flux by the above pathways should couple. The direction and magnitude of the NEM-induced net K flux did not correspond with the direction and magnitude of the forces relevant to K conductance or electroneutral KCl cotransport. Both the magnitude and direction of the NEM-activated K flux responded to the driving force for K/H exchange. We therefore conclude that NEM-induced K loss, like that by osmotically swollen Amphiuma red blood cells, is by an electroneutral K/H exchanger. In addition to the above studies, we evaluated the kinetic behavior of the volume- and NEM-induced K/H exchange flux pathways in media where Cl was replaced by SCN, NO3, para-aminohippurate (PAH), or gluconate. The anion replacement studies did not permit a distinction between K/H exchange and KCl cotransport, since, depending upon the anion used as a Cl replacement, partial inhibition or stimulation of volume-activated K/H exchange fluxes was observed. In contrast, all anions used were stimulatory to the NEM-induced K loss. Since, on the basis of force-flow analysis, both volume-and NEM-induced K loss are K/H exchange, it was necessary to reevaluate assumptions (i.e., anions serve as substrates and therefore probe the translocation step) associated with the use of anion replacement as a means of flux route identification. When viewed together with the force-flow studies, the Cl replacement studies suggest that anion effects upon K/H exchange are indirect. The different anions appear to alter mechanisms that couple NEM exposure and cell swelling to the activation of K/H exchange, as opposed to exerting direct effects upon K and H translocation