Indecomposable modules and Gelfand rings

It is proved that a commutative ring is clean if and only if it is Gelfand with a totally disconnected maximal spectrum. Commutative rings for which each indecomposable module has a local endomorphism ring are studied. These rings are clean and elementary divisor rings

Physical interpretation of stochastic Schroedinger equations in cavity QED

We propose physical interpretations for stochastic methods which have been developed recently to describe the evolution of a quantum system interacting with a reservoir. As opposed to the usual reduced density operator approach, which refers to ensemble averages, these methods deal with the dynamics of single realizations, and involve the solution of stochastic Schr\"odinger equations. These procedures have been shown to be completely equivalent to the master equation approach when ensemble averages are taken over many realizations. We show that these techniques are not only convenient mathematical tools for dissipative systems, but may actually correspond to concrete physical processes, for any temperature of the reservoir. We consider a mode of the electromagnetic field in a cavity interacting with a beam of two- or three-level atoms, the field mode playing the role of a small system and the atomic beam standing for a reservoir at finite temperature, the interaction between them being given by the Jaynes-Cummings model. We show that the evolution of the field states, under continuous monitoring of the state of the atoms which leave the cavity, can be described in terms of either the Monte Carlo Wave-Function (quantum jump) method or a stochastic Schr\"odinger equation, depending on the system configuration. We also show that the Monte Carlo Wave-Function approach leads, for finite temperatures, to localization into jumping Fock states, while the diffusion equation method leads to localization into states with a diffusing average photon number, which for sufficiently small temperatures are close approximations to mildly squeezed states.Comment: 12 pages RevTeX 3.0 + 6 figures (GIF format; for higher-resolution postscript images or hardcopies contact the authors.) Submitted to Phys. Rev.

Time scheduling in a peer-to-peer remote access laboratory for STEM education

Remote Access Laboratories (RAL) are online environments that allow users to access instruments through the Internet. Such environments enable users to control equipment and collect data without being present in the laboratory. This also means that users work in a disjoint manner and cannot co-ordinate equipment usage directly with each other, as they would do in regular on-site laboratories. Remote laboratory management systems deal with scheduling users, as most instruments cannot process multiple users' requests at the same time. Two scheduling strategies are predominantly used in RALs: time slotting and the queuing. This is straightforward in centralised, service-oriented environments, in particular, when instruments are available continuously throughout the day. In this paper, time scheduling in the context of a Distributed Peer-to-peer Remote laboratory featuring quest-based learning, is discussed. Here interaction with the entire system is organised around a set of learning activities or quests. This includes the experiments designed by users and the sharing of experiments by users. The providers of the experiments have the flexibility to put their systems online as per their capabilities. As such, the experiments availability become scarcer and must be judiciously assigned to the users who need them most

A cerebellar internal model calibrates a feedback controller involved in sensorimotor control

Animals can adjust their behavior in response to changes in the environment when these changes can be predicted. Here the authors show the role of the cerebellum in zebrafish that change their swimming as they adjust to long-lasting changes in visual feedback Animals must adapt their behavior to survive in a changing environment. Behavioral adaptations can be evoked by two mechanisms: feedback control and internal-model-based control. Feedback controllers can maintain the sensory state of the animal at a desired level under different environmental conditions. In contrast, internal models learn the relationship between the motor output and its sensory consequences and can be used to recalibrate behaviors. Here, we present multiple unpredictable perturbations in visual feedback to larval zebrafish performing the optomotor response and show that they react to these perturbations through a feedback control mechanism. In contrast, if a perturbation is long-lasting, fish adapt their behavior by updating a cerebellum-dependent internal model. We use modelling and functional imaging to show that the neuronal requirements for these mechanisms are met in the larval zebrafish brain. Our results illustrate the role of the cerebellum in encoding internal models and how these can calibrate neuronal circuits involved in reactive behaviors depending on the interactions between animal and environment

24th Annual Conference of the Australasian Association for Engineering Education (AAEE 2013)

BACKGROUND Group-work projects are commonly included in engineering courses to prepare the students for the workplace where this is the standard situation. One of the difficulties students face is that they do not have access to a unified file system where they can create and edit documents related to the project. Such a system reduces the risk of members duplicating work because someone was working offline for a substantial period, makes the integration of individuals' contributions simpler since all the work is visible and keeps the latest version of a document visible to all members. While the internet cloud has recently offered some solutions (e.g. Dropbox), a genuine Configuration Management solution is superior because it allows such features as merging different versions of a file and ensuring that only one person is able to edit a file at any given time: cloud solutions may allow multiple instances of file editing and therefore only stores the last instance of saving—deleting the changes made by the first person. Furthermore, Configuration Management systems store copies of each revision made to the files, so that it is possible to revert an individual file to a previous instance if it is found that subsequent changes were erroneous, unnecessary or undesired. PURPOSE To investigate the impacts the implementation of a comprehensive Configuration Management solution has on student behaviour with regard to file-sharing practices and how that affects the overall student experience, thereby helping achieve the learning outcomes. DESIGN/METHOD A configuration management system was set up so that each team could share files with each other and the staff also had access. Usage of the system was made 'compulsory' by allocating a few marks based on the quality of the system usage. Surveys were conducted following the 2011 and 2012 offerings of the course to assess the students' opinions on the operation of the system. RESULTS Most students saw that the benefits in easily managing their team's files outweighed the administrative cost of setting up and running the system. They also appreciated the teaching team having direct access to their files without having to actively share the files (which can be frustrating if the student shares a subset of files and omits a file which is critical). CONCLUSIONS Configuration Management systems are an industry standard that can improve student project outcomes by providing an environment where students are able to automatically manage their file sharing in a consistent and coherent fashion that protects against the errors that occur when manual administrative systems are implemented. The large majority of students appreciated the benefits of this system and were willing to devote the small amount of initial time required to setup the system because of the overall advantages, so this intervention resulted in positive student behaviour and outcomes. The staff also found it easier to manage the facilitation of the team project by having direct access to the students' files

Augmented and mixed reality features and tools for remote laboratory experiment

Augmented Reality (AR) is the process of overlaying meaningful interactive information in a live video stream for creating an enriched visual experience for users. Within Remote Access Laboratories (RAL) this enables users to gain design experience along with gaining knowledge about the particular experiment in question and potentially collaborate on design experiences. This paper focuses on the issues related to the applications of AR in RAL, the levels of AR in context of RAL and their effect on the learning tools. This paper also discusses the challenges of integrating a Natural User interface into the AR for RAL experiments. Finally it presets two example applications for AR in RAL experiment - Virtual Objects Creation and Object Identification and Tagging

24th Annual Conference of the Australasian Association for Engineering Education (AAEE 2013)

BACKGROUND Not enough children develop and maintain an interest in Science, Technology, Engineering and Maths (STEM) and as a result, there is a skill shortage to meet Australia's needs in STEM careers. An effective method for developing a deep understanding of STEM concepts is through conducting experiments. A project is introduced that aims to create an innovative and unique online system for developing children's STEM concepts using a quest-based game that incorporates remotely accessed laboratories (RAL). With the support of online experts, plans and guides, learners will be making and assembling experiments locally and interfacing them to the Internet so others can use them remotely. Communication and collaboration will be fostered through game-style guilds where young people can safely tap into the expertise of their peers and experts as well as share their own knowledge. PURPOSE The research aims to improve the quality of the RAL experience by conducting technical research to optimise the online experience for users and pedagogical research to improve communication and collaboration around the use of remotely accessed laboratories. DESIGN/METHOD A design based research methodology is being employed to develop and test a prototype of a scalable technical and communication system that will be evaluated in field trials conducted in schools and informal learning contexts. Refinement of the design will involve an iterative process informed by observations, interviews, expert panel review and usability testing as well as mathematical modelling and test bed simulation. Technical and pedagogical peer-to-peer models will be developed. RESULTS It is anticipated that preliminary evaluation of this system will indicate the technical requirements for an end-to-end maker based system. Evaluation of user trials will identify ways maker communities supported by gamified systems for communication, collaboration and motivation can contribute to the learning experience of others. Expert review and participant feedback will indicate if user generated content in the RAL space offers a significant mechanism to not only engage children, but develop access to more experiments. CONCLUSIONS Through this research project we will demonstrate the potential for alternative delivery models for RAL that are not necessarily restricted to large institutions. Through a change in the delivery method and development of RAL experiments, maker communities have the potential to broaden engagement in the remote lab experience. Gamification of the RAL experience has the potential to increase communication and collaboration between RAL users

Characteristics of contralateral carcinomas in patients with differentiated thyroid cancer larger than 1 cm

Purpose: Traditionally, total thyroidectomy has been advocated for patients with tumors larger than 1 cm. However, according to the ATA and NCCN guidelines (2015, USA), patients with tumors up to 4 cm are now eligible for lobectomy. A rationale for adhering to total thyroidectomy might be the presence of contralateral carcinomas. The purpose of this study was to describe the characteristics of contralateral carcinomas in patients with differentiated thyroid cancer (DTC) larger than 1 cm. Methods: A retrospective study was performed including patients from 17 centers in 5 countries. Adults diagnosed with DTC stage T1b-T3 N0-1a M0 who all underwent a total thyroidectomy were included. The primary endpoint was the presence of a contralateral carcinoma. Results: A total of 1

Tumour necrosis factor production and natural killer cell activity in peripheral blood during treatment with recombinant tumour necrosis factor.

Tumour necrosis factor (TNF) has been found to be an important immunomodulator. Among other functions TNF activates natural killer (NK) cells and stimulates monocytes/macrophages in an autocrine fashion. TNF production and NK activity in peripheral blood mononuclear cells were determined in a clinical phase I study in which recombinant human (rh) TNF was administered as a continuous infusion weekly for a period of 8 weeks. Even though TNF production and NK activity were significantly reduced directly after rhTNF infusion the effect proved to be transient and most pronounced at the first rhTNF administration. One day after completion of the rhTNF infusion the peripheral cells released more TNF into the supernatant compared to TNF activity immediately before the rhTNF infusion. This effect was conspicuous in non-stimulated cultures. After repeated rhTNF infusions both stimulated and non-stimulated TNF production of the peripheral blood mononuclear cells was increased. NK cell activity was also enhanced after repeated cycles of rhTNF administration as compared to early rhTNF treatment. Thus, repeated rhTNF infusions lead to a stimulatory effect on TNF production and NK activity of peripheral blood cells