The Electrostatic Ion Beam Trap : a mass spectrometer of infinite mass range

We study the ions dynamics inside an Electrostatic Ion Beam Trap (EIBT) and show that the stability of the trapping is ruled by a Hill's equation. This unexpectedly demonstrates that an EIBT, in the reference frame of the ions works very similar to a quadrupole trap. The parallelism between these two kinds of traps is illustrated by comparing experimental and theoretical stability diagrams of the EIBT. The main difference with quadrupole traps is that the stability depends only on the ratio of the acceleration and trapping electrostatic potentials, not on the mass nor the charge of the ions. All kinds of ions can be trapped simultaneously and since parametric resonances are proportional to the square root of the charge/mass ratio the EIBT can be used as a mass spectrometer of infinite mass range

Induction of myeloid leukaemia by whole-body single exposure of CBA male mice to x-rays.

A curvilinear dose response of myeloid leukaemia induction in the CBA male mouse was obtained after single whole-body X-irradiation at about 3 months of age. This strain has a very low spontaneous incidence of the disease and no cases were found in the unirradiated controls. The incidence was independent of dose rate over the range used (4.2-552 rad/min). Diagnosis required histopathological examination of various body tissues, the gross anatomical changes being easily confused with other haemopoietic disorders, but a few cases were recognized in life from blood samples. Curve-fitting to various models based on theories of radiocarcinogenic mechanism is described

Pulmonary Adenomata Induced by Carcinogen Treatment in Organ Culture. Influence of Increasing Amounts of Carcinogen

Explants of lung from 1 month old inbred BALB/c mice were cultured in vitro for 4 days with 3-methylcholanthrene added to the culture medium at various dose levels. They were subsequently implanted subcutaneously into 6-week-old mice of the same strain

Auditor independence: a qualitative study of the perceptions of auditors

The trustworthiness of a financial audit report rests on the perception of auditor independence. However, several factors can affect those perceptions, ultimately affecting market confidence. This study aims at providing a deep understanding of auditors‟ perceptions of auditor independence, particularly analysing whether and how their perceptions are affected either by the provision of non-audit services, competition, the size and tenure of the audit firm or the client‟s financial condition. Qualitative research was held through semi-structured interviews. Both the provision of non-audit services and tenure have generated great consensus amongst interviewees as impacting auditor independence. Rotation and litigation exposure were mainly perceived as enhancement factors.info:eu-repo/semantics/publishedVersio

The Induction of Adenomata in Mouse Lung Homografts by Chemical Carcinogens

Implants of lung from 18-day-old embryo BALB/c mice of an inbred strain were exposed to 3,4-benz(a)pyrene or 1,2,5,6-dibenzanthracene and introduced subcutaneously into 6-week-old mice of the same strain. Lung adenomata developed within 16 weeks

Classroom dialogue and digital technologies: A scoping review

AbstractThis article presents a systematic scoping review of the literature focusing on interactions between classroom dialogue and digital technology. The first review of its type in this area, it both maps extant research and, through a process of thematic synthesis, investigates the role of technology in supporting classroom dialogue. In total, 72 studies (published 2000–2016) are analysed to establish the characteristics of existing evidence and to identify themes. The central intention is to enable researchers and others to access an extensive base of studies, thematically analysed, when developing insights and interpretations in a rapidly changing field of study. The discussion illustrates the interconnectedness of key themes, placing the studies in a methodological and theoretical context and examining challenges for the future.</jats:p

Evidence of sympathetic cooling of Na+ ions by a Na MOT in a hybrid trap

A hybrid ion-neutral trap provides an ideal system to study collisional dynamics between ions and neutrals. This system provides a general cooling method that can be applied to optically inaccessible species and can also potentially cool internal degrees of freedom. The long range polarization potentials ($V\propto-\alpha/r^4$) between ions and neutrals result in large scattering cross sections at cold temperatures, making the hybrid trap a favorable system for efficient sympathetic cooling of ions by collisions with neutral atoms. We present experimental evidence of sympathetic cooling in a hybrid trap of \ce{Na+} ions, which are closed shell and therefore do not have a laser induced atomic transition, by equal mass cold Na atoms in a magneto-optical trap (MOT).Comment: 7 figure

Realising ‘dialogic intentions’ when working with a microblogging tool in secondary school classrooms

In this paper we argue that joint teacher and student awareness of dialogic intentions (DIs) in lessons can focus and guide students’ spoken dialogic interactions in the context of the use of digital technology. We focus on DI as a factor in promoting metacognitive awareness of productive dialogue amongst students, considering how teachers in ‘dialogic classrooms’ express DIs and how the use of a microblogging tool (Talkwall) can support, enhance or disrupt students’ realisation of these intentions. Data consist of 17 lessons with Year 7 students (aged 11-12), taught by six teachers and covering three subject areas: English, science and geography. A systematic model is used for analysis of technology-focused student interactions, revealing how technology affordances and constraints are implicated in the realisation of DI. This paper is significant in examining how the ability to engage in dialogue can be focused through learning intentions, or set of intentions, within lessons. Further, it considers how specific technological affordances are central to the ways in which technology is implicated in the creation of a relational space for intra-action that might support teaching and learning.The DiDiAC research project is funded by the Research Council of Norway [FINNUT/Project No: 254761] and is registered and approved by the Norwegian data protection service (NSD