Transdisciplinary qualities in practice doctorates

Doctoral programmes in which candidates research their own practice can be characterised as having transdisciplinary (TD) qualities. While most of the emphasis in the literature and in policy on TD is on research in teams, we argue for an expansion of the scope in the conception and understanding of TD research to include the way it can be articulated and assessed in practice-led and practice-based doctorates. In this sense, it is worth exploring instances of doctoral programmes that potentially allow doctoral researchers to undertake projects that have TD qualities. In these doctoral projects, researchers draw from a variety of perspectives, for example from their work practices, the theorisation of those practices, experiential learning, multiple disciplinary knowledge and approaches as well as communications and networking with appropriate stakeholders. Drawing from previous scholarship of TD in other fields we analyse and evaluate the TD qualities of a particular doctoral programme. This analysis reveals a set of qualities recognised by the literature as TD and relevant to doctoral researchers: Researching collaboratively with stakeholders; Diversity of disciplinary expertise and assessment criteria; Integration of different methodologies; Situating the research in multiple contexts; Impact on the ‘situation’ through novel procedures or products; Ethics and the importance of trust; Reflection/reflexivity. The paper posits a convergence between practice doctorates and TD research and demonstrates how TD qualities help doctoral candidates to situate their research at the interface between academia and their professional work and develop projects that have creative and beneficial relevance for practice

An Inquiry-based approach to the Franck-Hertz experiment

In this study we present the results of an inquiry-driven learning path experienced by a sample of 15 selected engineering undergraduates engaged to perform the Franck-Hertz experiment. Before being involved in this experimental activity, the students received a traditional lecture-based instruction on the fundamental concepts of quantum mechanics. Despite the instructor\u2019s introduction to specific technological/engineering-based contents during the course, the students\u2019 answers to an open-ended questionnaire, administered at the end of the lectures, demonstrated that the acquired knowledge was characterized by a strictly theoretical vision of quantum science, basically in terms of an artificial mathematical framework having very poor connections with the real world. This could be ascribed to the many difficulties that students demonstrated to have in order to deal with concepts at scales in which they cannot have a direct experience in their everyday life, especially at microscopic and sub-microscopic scales. In order to fulfil these lacks, the students were invited to actively participate to an experimental activity within an inquiry-based learning environment at the Laboratory of Condensed Matter Physics at the Department of Physics and Chemistry of the University of Palermo. The Franck- Hertz experiment was introduced to the students by starting from the problem of finding an experimental confirmation of the Bohr\u2019s postulates asserting that atoms can absorb energy only in quantum portions. By following the lines of a scientific inquiry, the students, working in group, performed a questioning activity that naturally guided them throughout the steps of the Franck- Hertz experiment

Noise driven translocation of short polymers in crowded solutions

In this work we study the noise induced effects on the dynamics of short polymers crossing a potential barrier, in the presence of a metastable state. An improved version of the Rouse model for a flexible polymer has been adopted to mimic the molecular dynamics by taking into account both the interactions between adjacent monomers and introducing a Lennard-Jones potential between all beads. A bending recoil torque has also been included in our model. The polymer dynamics is simulated in a two-dimensional domain by numerically solving the Langevin equations of motion with a Gaussian uncorrelated noise. We find a nonmonotonic behaviour of the mean first passage time and the most probable translocation time, of the polymer centre of inertia, as a function of the polymer length at low noise intensity. We show how thermal fluctuations influence the motion of short polymers, by inducing two different regimes of translocation in the molecule transport dynamics. In this context, the role played by the length of the molecule in the translocation time is investigated.Comment: 11 pages, 3 figures, to appear in J. Stat. Mechanics: Theory and Experiment, 200

Biofeedback for gait retraining based on real-time estimation of tibiofemoral joint contact forces

Biofeedback assisted rehabilitation and intervention technologies have the potential to modify clinically relevant biomechanics. Gait retraining has been used to reduce the knee adduction moment, a surrogate of medial tibiofemoral joint loading often used in knee osteoarthritis research. In this study we present an electromyogram-driven neuromusculoskeletal model of the lower-limb to estimate, in real-time, the tibiofemoral joint loads. The model included 34 musculotendon units spanning the hip, knee, and ankle joints. Full-body inverse kinematics, inverse dynamics, and musculotendon kinematics were solved in real-time from motion capture and force plate data to estimate the knee medial tibiofemoral contact force (MTFF). We analyzed 5 healthy subjects while they were walking on an instrumented treadmill with visual biofeedback of their MTFF. Each subject was asked to modify their gait in order to vary the magnitude of their MTFF. All subjects were able to increase their MTFF, whereas only 3 subjects could decrease it, and only after receiving verbal suggestions about possible gait modification strategies. Results indicate the important role of knee muscle activation patterns in modulating the MTFF. While this study focused on the knee, the technology can be extended to examine the musculoskeletal tissue loads at different sites of the human body

Biofeedback for gait retraining based on real-time estimation of tibiofemoral joint contact forces

Biofeedback assisted rehabilitation and intervention technologies have the potential to modify clinically relevant biomechanics. Gait retraining has been used to reduce the knee adduction moment, a surrogate of medial tibiofemoral joint loading often used in knee osteoarthritis research. In this study we present an electromyogram-driven neuromusculoskeletal model of the lower-limb to estimate, in real-time, the tibiofemoral joint loads. The model included 34 musculotendon units spanning the hip, knee, and ankle joints. Full-body inverse kinematics, inverse dynamics, and musculotendon kinematics were solved in real-time from motion capture and force plate data to estimate the knee medial tibiofemoral contact force (MTFF). We analyzed 5 healthy subjects while they were walking on an instrumented treadmill with visual biofeedback of their MTFF. Each subject was asked to modify their gait in order to vary the magnitude of their MTFF. All subjects were able to increase their MTFF, whereas only 3 subjects could decrease it, and only after receiving verbal suggestions about possible gait modification strategies. Results indicate the important role of knee muscle activation patterns in modulating the MTFF. While this study focused on the knee, the technology can be extended to examine the musculoskeletal tissue loads at different sites of the human body

Uso de microeletrodos interligados de ouro revestidos com filmes poliméricos para a detecção de pesticidas em água por espectroscopia de impedância.

bitstream/CNPDIA-2009-09/11853/1/DOC25_2006.pd

Weak temporal signals can synchronize and accelerate the transition dynamics of biopolymers under tension

In addition to thermal noise, which is essential to promote conformational transitions in biopolymers, cellular environment is replete with a spectrum of athermal fluctuations that are produced from a plethora of active processes. To understand the effect of athermal noise on biological processes, we studied how a small oscillatory force affects the thermally induced folding and unfolding transition of an RNA hairpin, whose response to constant tension had been investigated extensively in both theory and experiments. Strikingly, our molecular simulations performed under overdamped condition show that even at a high (low) tension that renders the hairpin (un)folding improbable, a weak external oscillatory force at a certain frequency can synchronously enhance the transition dynamics of RNA hairpin and increase the mean transition rate. Furthermore, the RNA dynamics can still discriminate a signal with resonance frequency even when the signal is mixed among other signals with nonresonant frequencies. In fact, our computational demonstration of thermally induced resonance in RNA hairpin dynamics is a direct realization of the phenomena called stochastic resonance (SR) and resonant activation (RA). Our study, amenable to experimental tests using optical tweezers, is of great significance to the folding of biopolymers in vivo that are subject to the broad spectrum of cellular noises.Comment: 22 pages, 7 figure

Investigating the properties of AGN feedback in hot atmospheres triggered by cooling-induced gravitational collapse

Radiative cooling may plausibly cause hot gas in the centre of a massive galaxy, or galaxy cluster, to become gravitationally unstable. The subsequent collapse of this gas on a dynamical timescale can provide an abundant source of fuel for AGN heating and star formation. Thus, this mechanism provides a way to link the AGN accretion rate to the global properties of an ambient cooling flow, but without the implicit assumption that the accreted material must have flowed onto the black hole from 10s of kiloparsecs away. It is shown that a fuelling mechanism of this sort naturally leads to a close balance between AGN heating and the radiative cooling rate of the hot, X-ray emitting halo. Furthermore, AGN powered by cooling-induced gravitational instability would exhibit characteristic duty cycles (delta) which are redolent of recent observational findings: delta is proportional to L_X/sigma_{*}^{3}, where L_X is the X-ray luminosity of the hot atmosphere, and sigma_{*} is the central stellar velocity dispersion of the host galaxy. Combining this result with well-known scaling relations, we deduce a duty cycle for radio AGN in elliptical galaxies that is approximately proportional to M_{BH}^{1.5}, where M_{BH} is the central black hole mass. Outburst durations and Eddington ratios are also given. Based on the results of this study, we conclude that gravitational instability could provide an important mechanism for supplying fuel to AGN in massive galaxies and clusters, and warrants further investigation.Comment: Accepted for publication in MNRAS. 8 page

Noise effects in polymer dynamics

The study of the noise induced effects on the dynamics of a chain molecule crossing a potential barrier, in the presence of a metastable state, is presented. A two-dimensional stochastic version of the Rouse model for a flexible polymer has been adopted to mimic the molecular dynamics and to take into account the interactions between adjacent monomers. We obtain a nonmonotonic behavior of the mean first passage time and its standard deviation, of the polymer centre of inertia, with the noise intensity. These findings reveal a noise induced effect on the mean crossing time. The role of the polymer length is also investigated.Comment: 6 pages, 5 figures, to appear in Intern. Journ. of Bifurcation and Chaos, 200