Do Childhood Vaccines Have Non-Specific Effects on Mortality

A recent article by Kristensen et al. suggested that measles vaccine and bacille Calmette–Guérin (BCG) vaccine might\ud reduce mortality beyond what is expected simply from protection against measles and tuberculosis. Previous reviews of the potential effects of childhood vaccines on mortality have not considered methodological features of reviewed studies. Methodological considerations play an especially important role in observational assessments, in which selection factors for vaccination may be difficult to ascertain. We reviewed 782 English language articles on vaccines and childhood mortality and found only a few whose design met the criteria for methodological rigor. The data reviewed suggest that measles vaccine delivers its promised reduction in mortality, but there is insufficient evidence to suggest a mortality benefit above that caused by its effect on measles disease and its sequelae. Our review of the available data in the literature reinforces how difficult answering these considerations has been and how important study design will be in determining the effect of specific vaccines on all-cause mortality.\u

Tractable constraints on ordered domains

AbstractFinding solutions to a constraint satisfaction problem is known to be an NP-complete problem in general, but may be tractable in cases where either the set of allowed constraints or the graph structure is restricted. In this paper we identify a restricted set of contraints which gives rise to a class of tractable problems. This class generalizes the notion of a Horn formula in propositional logic to larger domain sizes. We give a polynomial time algorithm for solving such problems, and prove that the class of problems generated by any larger set of constraints is NP-complete

Student Perceptions Of Online Interactive Versus Traditional Lectures; Or How I Managed Not To Fall Asleep With My Eyes Open

Universities are increasingly experimenting with the online domain to connect with busy and digital-savvy students and counter the decline in face-to-face lecture attendance More often than not universities are offering videoed lectures or PowerPoints with lecturer voice-overs as a way of delivering content. Evidence suggests that while these techniques may provide the flexibility required, some content needs more personalised delivery. In this article the authors explore the development and delivery of an online lecture format. Using a combination of video, text and interactive cell technology, this online offering was trialed in a unit focused on the education of students with disability in inclusive classrooms. Using the Attitude toward Computer Aided Instruction Scale (ACAIS) (Allen, 1986) the author’s surveyed 159, 3rd year pre-service teachers and asked them to compare the online presentation format with a traditional face-to-face lecture. The students were enthusiastic about using the online format, with data analysis revealing eleven of the twelve ACAIS criteria were highly significant in favour of this approach. The results of the survey are presented and discussed critically in the context of the challenges and opportunities online delivery of course content presents to universities

Examining student ICT ownership, use and preferences towards electronically delivered learning resources in Nakhon Phanom University and Sakon Nakhon Rajabhat University

The objectives of this research were 1) to find students’ ownership of technology devices, ownership, soft-ware facility, and preferences, 2) to find out what devices instructors use in the classroom, 3) to find out how the students use the online learning that the university provided for them, and 4) to examine students’ software skills. The questionnaire and the interview instruments were designed to clarify participants’ attitudes, and used a Likert scale. Surveys and qualitative research design were developed using Qualtrics software, which is an online research survey tool that can be used for a whole range of data gathering purposes applicable to Higher Degree Research. The samples were the students in both universities (Nakhon Phanom University and Sakon Nakhon Rajabhat University), a total of 977 people. A statistical computer program was employed

Redefining education: sustaining 1 to 1 computing strategies in Western Australian schools

In 1993 the first WA private school adopted a 1 to 1 computing strategy and then ten years later the first government school did so. With the advent of the Digital Education Revolution initiative many schools in WA commenced 1 to 1 strategies and it has almost become an expectation in secondary schools. Our snapshots studies involved two new government schools and along established elite private school that had a similar vision for learning with digital technologies. The two government schools had 1 to 1 strategies, but had found that their chosen tablet PC was not robust enough, and had concluded that the current policy was not sustainable. They were debating the merits of BYOD or BYOT strategies in the light of constraints and the nature of their clientele. The private school, unlike most of its peers, had not had a 1 to 1 strategy but was planning to do so using iPads. However, it appeared that they already had an informal BYOT strategy. In this paper we discuss the differing situations these schools have found themselves in, the vision they have for learning with digital technologies, and the issues they are debating that will allow them to implement and sustain this visio

Schwinger-Dyson approach to non-equilibrium classical field theory

In this paper we discuss a Schwinger-Dyson [SD] approach for determining the time evolution of the unequal time correlation functions of a non-equilibrium classical field theory, where the classical system is described by an initial density matrix at time $t=0$. We focus on $\lambda \phi^4$ field theory in 1+1 space time dimensions where we can perform exact numerical simulations by sampling an ensemble of initial conditions specified by the initial density matrix. We discuss two approaches. The first, the bare vertex approximation [BVA], is based on ignoring vertex corrections to the SD equations in the auxiliary field formalism relevant for 1/N expansions. The second approximation is a related approximation made to the SD equations of the original formulation in terms of $\phi$ alone. We compare these SD approximations as well as a Hartree approximation with exact numerical simulations. We find that both approximations based on the SD equations yield good agreement with exact numerical simulations and cure the late time oscillation problem of the Hartree approximation. We also discuss the relationship between the quantum and classical SD equations.Comment: 36 pages, 5 figure

Non-Equilibrium Large N Yukawa Dynamics: marching through the Landau pole

The non-equilibrium dynamics of a Yukawa theory with N fermions coupled to a scalar field is studied in the large N limit with the goal of comparing the dynamics predicted from the renormalization group improved effective potential to that obtained including the fermionic backreaction. The effective potential is of the Coleman-Weinberg type. Its renormalization group improvement is unbounded from below and features a Landau pole. When viewed self-consistently, the initial time singularity does not arise. The different regimes of the dynamics of the fully renormalized theory are studied both analytically and numerically. Despite the existence of a Landau pole in the model, the dynamics of the mean field is smooth as it passes the location of the pole. This is a consequence of a remarkable cancellation between the effective potential and the dynamical chiral condensate. The asymptotic evolution is effectively described by a quartic upright effective potential. In all regimes, profuse particle production results in the formation of a dense fermionic plasma with occupation numbers nearly saturated up to a scale of the order of the mean field. This can be interpreted as a chemical potential. We discuss the implications of these results for cosmological preheating.Comment: 36 pages, 14 figures, LaTeX, submitted to Physical Review

Analysing the Impact of Built-In and External Social Tools in a MOOC on Educational Technologies

Proocedings of: 8th European Conference on Technology Enhanced Learning: Scaling Up Learning for Sustained Impact (EC-TEL 2013). Paphos, Cyprus, September 17-21, 2013MOOCs have been a disruptive educational trend in the last months. Some MOOCs just replicate traditional teaching pedagogies, adding multimedia elements like video lectures. Others go beyond, trying to engage the massive number of participants by promoting discussions and relying on their contributions to the course. MOOC platforms usually provide some built-in social tools for this purpose, although instructors or participants may suggest others to foster discussions and crowdsourcing. This paper analyses the impact of two built-in (Q&A and forum) and three external social tools (Facebook, Twitter and MentorMob) in a MOOC on educational technologies. Most of the participants agreed on the importance of social tools to be in touch with their partners and share information related to the course, the forum being the one preferred. Furthermore, the lessons learned from the enactment of this MOOC employing social tools are summarized so that others may benefit from them.This work has been funded by the Spanish Ministry of Economy and Competitiveness Project TIN2011-28308-C03-01, the Regional Government of Madrid project S2009/TIC-1650, and the postdoctoral fellowship Alianza 4 Universidades.Publicad

The Role of the Magnetic Field in the Interstellar Medium of the Post-Starburst Dwarf Irregular Galaxy NGC 1569

(abridged) NGC 1569 is a nearby dwarf irregular galaxy which underwent an intense burst of star formation 10 to 40 Myr ago. We present observations that reach surface brightnesses two to eighty times fainter than previous radio continuum observations and the first radio continuum polarization observations. These observations allow us to probe the relationship of the magnetic field of NGC 1569 to the rest of its interstellar medium. We confirm the presence of an extended radio continuum halo at 20 cm and see for the first time the radio continuum feature associated with the western Halpha arm at wavelengths shorter than 20cm. The spectral index trends in this galaxy support the theory that there is a convective wind at work in this galaxy. We derive a total magnetic field strength of 38 microG in the central regions and 10-15 microG in the halo. The magnetic field is largely random in the center of the galaxy; the uniform field is ~3-9 microG and is strongest in the halo. We find that the magnetic pressure is the same order of magnitude but, in general, a factor of a few less than the other components of the interstellar medium in this galaxy. The uniform magnetic field in NGC 1569 is closely associated with the Halpha bubbles and filaments. We suggest that a supernova-driven dynamo may be operating in this galaxy. The outflow of hot gas from NGC 1569 is clearly shaping the magnetic field, but the magnetic field in turn may be aiding the outflow by channeling gas out of the disk of the galaxy. Dwarf galaxies with extended radio continuum halos like that of NGC 1569 may play an important role in magnetizing the intergalactic medium.Comment: ApJ accepted. 56 pages, 14 figures (low resolution), 8 tables. Version with high resolution figures at http://www.astro.virginia.edu/~aak8t/data/n1569/ms.pd