Flow of DNA solutions in a microfluidic gradual contraction

The flow of λ-DNA solutions in a gradual micro-contraction was investigated using direct measurement techniques. The effects on DNA transport in microscale flows are significant because the flow behavior is influenced by macromolecular conformations, both viscous and elastic forces dominate inertial forces at this length scale, and the fully extended length of the molecule approaches the characteristic channel length w_c (L/w_c ∼ 0.13). This study examines the flow of semi-dilute and entangled DNA solutions in a gradual planar micro-contraction for low Reynolds numbers (3.7 × 10⁻⁶< Re < 3.1 × 10⁻¹) and high Weissenberg numbers (0.4 < Wi < 446). The semi-dilute DNA solutions have modest elasticity number, El = Wi/Re = 55, and do not exhibit viscoelastic behavior. For the entangled DNA solutions, we access high elasticity numbers (7.9 × 10³< El < 6.0 × 10⁵). Video microscopy and streak images of entangled DNA solution flow reveal highly elastic behavior evidenced by the presence of large, stable vortices symmetric about the centerline and upstream of the channel entrance. Micro-particle image velocimetry measurements are used to obtain high resolution, quantitative velocity measurements of the vortex growth in this micro-contraction flow. These direct measurements provide a deeper understanding of the underlying physics of macromolecular transport in microfluidic flow, which will enable the realization of enhanced designs of lab-on-a-chip systems.     

On disciplinary judgement

This paper enquires into the grounds for convergence of judgements in a situation of blind peer review, where reviewers are asked to assess the standing of scholars in a disciplinary field. The paper first considers traditional accounts of peer review and threats to its reliability and validity. Next it examines the grounds for disciplinary sociality and different forms of expertise that stratify the disciplinary field. The paper will report the results of an initial study of peer review judgements in the disciplines of Law, Psychology and Historical Studies. The paper will conclude by assessing the variable merits of micro- and macro-sociological explanations in accounting for the phenomenon of convergent disciplinary judgements. A case will be made for the explanatory power of social norms.     

For the Good of the Species: Gary Francione and the Omnipresence of Eugenics in Animal Rights Rhetoric

By bringing critical animal studies into conversation with communication, this article completes 3 tasks: First, it complicates the communication discipline’s understanding of the animal rights movement by presenting its oft-ignored tensions and conflicting paradigms; second, it reveals how eugenical rhetoric has been foundational both in defending human/animal exploitation and in developing prototypical animal advocacy practices; third, using a critical public address–inspired approach, it deconstructs vegan abolitionist Gary Francione’s purportedly ultraradical rhetoric, revealing its problematic eugenical underpinnings. This revelation not only complicates Francione’s radical status but also questions the ethical legitimacies of a conventional, Western rights-based paradigm of animal rights.     

“Are you really ready to change?” An actor-oriented perspective on a farmers training setting in Madagascar

Far from following a linear process from its conception to its implementation, an educational design often involves discrepancies between what its promoters intended and what the participants actually do. In this paper, drawing from a sociocultural perspective to learning, we focus our attention precisely on some of the discrepancies observed during the implementation of a training program. We consider these discrepancies not as mistakes or misunderstandings, but rather as indicators of the communicative dimension of any intervention and as “windows” on the processes of change and on learning. The program we have studied here was set up in Madagascar and was sustained by a Swiss cooperation agency addressed to farmers in the field of forestry. In this research, we adopted an actor-oriented perspective in order to understand the promoters’ and the beneficiaries’ interpretation of the design and the way they developed innovative strategies to resolve the difficulties they faced. We chose some “critical incidents” from the data gathered through ethnographical research and show how the whole process of the conception and the implementation of the program was deeply affected by both the power dynamic embedded in the history of the relationship between the Swiss and the Malagasy groups and by their own cultural and institutional constraints. In conclusion, we discuss the significance of an actor-oriented perspective that contributes to a better understanding of the social and cultural dimensions of learning and allows us to relate the here and now micro-phenomena to the larger anthropological, social, and political scenery.     

Social support, attachment, and psychopathology in high risk formerly maltreated adults

OBJECTIVE: The aim of this study was to examine the relationships among social support, attachment security, and psychopathology in an adult sample of high risk abuse survivors. Attachment security was conceptualized in terms of two underlying dimensions, the working models of self and other. METHOD: Sixty-six participants (24 men and 42 women) who met conditions for physical or sexual abuse were recruited from the greater Boston area. They completed the "Record of Maltreatment Experiences." the "Relationship Scales Questionnaire," the "Norbeck Social Support Questionnaire," and multiple measures of psychopathology. RESULTS: When multiple risk and protective factors were examined concurrently (e.g., social support, attachment, abuse history, IQ, SES), a negative view of self (one of the attachment poles) was the strongest predictor of overall psychopathology. Social support did not emerge as a significant direct predictor of psychopathology, once the effects of negative view of self were accounted for. However, among participants low on social support, in comparison to those who are high, a negative view of self was more highly correlated with some psychopathology measures. CONCLUSIONS: These findings indicate that among maltreatment survivors, negative view of self emerges as the most substantial predictor of psychopathology when examined in combination with other relevant risk factors.     

University reputation and undergraduates’ self-perceived employability: mediating influence of experiential learning activities

ABSTRACT

Stratification, in the form of silent exclusion that is experienced by some groups of students because of the perceived low reputation of the university attended, and which the students have no control over, has been observed as a social menace that works against the concept of equity in education. To address this problem, a need exists for universities with lower reputations to go the extra mile to develop the employability skills of their students, which, in turn, will enhance their self-perception of employability. The major objective of this study was to investigate the influence of experiential learning activities on the relationship between university reputation and self-perceived employability among undergraduates in South African universities. Data were collected by means of an adapted questionnaire from 402 respondents drawn from two universities in the same province in South Africa. To achieve our objective, four hypotheses were formulated and tested through Structural Equation Modelling (SEM) using AMOS 25. The findings show that both direct and indirect effects of university reputation on undergraduates’ perceived employability through experiential learning activities are positively significant. To minimise the negative effects that universities with low reputations are likely to have on undergraduates’ acquisition of experiential learning, on their self-perceived employability, and subsequently on their employment prospects, the government, the Department of Higher Education and universities (particularly, the low-rated ones in South Africa) need to put in place some timely interventions, some of which are suggested in the study.     

New Zealand Māori-medium teacher education: an examination of students’ academic confidence and preparedness

Little research has been concerned with gauging Māori–medium teacher education students’ academic confidence in bilingual settings making the development of appropriate curricula and broad policy a difficult task. Drawing on a convenience sample of 84 primary teacher education students on a three-year B.Ed Māori-medium program, this study uses self-reported measures to assess students’ academic confidence and preparedness in English and Māori. Results suggest that the students are less academically confident in Māori than in English, and that this discrepancy is most pronounced in academic speaking and reading. Consequently, it is proposed that curriculum developers place emphasis on the development of both Māori academic speaking and reading throughout the course of Māori-medium teacher education programs. Finally, it is argued that standardised assessments that track both confidence and preparedness, and the productive and receptive abilities of Māori-medium teacher education students throughout university would bolster the regeneration of Māori-medium education in New Zealand.     

Mathematical Model and Simulation of Cutting Force in Plunge Milling Process

Plunge milling,also calledZ-axis milling,is one ofthe most effective machining methods in high speed metalremoval machining.Asfor curvedsurface of difficult-to-ma-chine material ,slot-cut working and machining withlongercutter of suspendinglength,the mach…