Discriminative, generative, and imitative learning

Thesis (Ph. D.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2002.Includes bibliographical references (leaves 201-212).I propose a common framework that combines three different paradigms in machine learning: generative, discriminative and imitative learning. A generative probabilistic distribution is a principled way to model many machine learning and machine perception problems. Therein, one provides domain specific knowledge in terms of structure and parameter priors over the joint space of variables. Bayesian networks and Bayesian statistics provide a rich and flexible language for specifying this knowledge and subsequently refining it with data and observations. The final result is a distribution that is a good generator of novel exemplars. Conversely, discriminative algorithms adjust a possibly non-distributional model to data optimizing for a specific task, such as classification or prediction. This typically leads to superior performance yet compromises the flexibility of generative modeling. I present Maximum Entropy Discrimination (MED) as a framework to combine both discriminative estimation and generative probability densities. Calculations involve distributions over parameters, margins, and priors and are provably and uniquely solvable for the exponential family. Extensions include regression, feature selection, and transduction. SVMs are also naturally subsumed and can be augmented with, for example, feature selection, to obtain substantial improvements. To extend to mixtures of exponential families, I derive a discriminative variant of the Expectation-Maximization (EM) algorithm for latent discriminative learning (or latent MED).(cont.) While EM and Jensen lower bound log-likelihood, a dual upper bound is made possible via a novel reverse-Jensen inequality. The variational upper bound on latent log-likelihood has the same form as EM bounds, is computable efficiently and is globally guaranteed. It permits powerful discriminative learning with the wide range of contemporary probabilistic mixture models (mixtures of Gaussians, mixtures of multinomials and hidden Markov models). We provide empirical results on standardized data sets that demonstrate the viability of the hybrid discriminative-generative approaches of MED and reverse-Jensen bounds over state of the art discriminative techniques or generative approaches. Subsequently, imitative learning is presented as another variation on generative modeling which also learns from exemplars from an observed data source. However, the distinction is that the generative model is an agent that is interacting in a much more complex surrounding external world. It is not efficient to model the aggregate space in a generative setting. I demonstrate that imitative learning (under appropriate conditions) can be adequately addressed as a discriminative prediction task which outperforms the usual generative approach. This discriminative-imitative learning approach is applied with a generative perceptual system to synthesize a real-time agent that learns to engage in social interactive behavior.by Tony Jebara.Ph.D

Investigating practice integration of independent prescribing by community pharmacists using normalization process theory: a cross-sectional survey.

Independent prescribing (IP) has not been extensively investigated in community pharmacy (CP). Normalization Process Theory (NPT) constructs help explain how interventions are integrated into practice and include: 'coherence' (understanding), 'cognitive participation' (what promotes engagement), 'collective action' (integration with existing systems), 'reflexive monitoring (evaluation). The aim of this study was to use NPT to investigate the integration of pharmacist IP in CP. NHS Scotland Pharmacy First Plus (PFP) is a community pharmacy IP service. Questionnaire items were developed using the NPT derived Normalisation MeAsure Development (NoMAD) tool for an online survey of all PFP IP pharmacists. Demographic data were analysed descriptively and scale scores (calculated from item scores for the 4 NPT constructs) were used for inferential analysis. There was a 73% (88/120) response rate. Greater than 90% 'strongly agreed' / 'agreed' to NoMAD items relating to most NPT constructs. However, responses to 'collective action' items were diverse with more participants answering 'neither agree nor disagree' or 'disagree'. A statistically significant difference in NPT construct scale scores with significant p-values (ranging from p<0.001 to p=0.033) was shown on all the NPT constructs for the variable 'On average, how often do you consult with patients under the PFP service?'. This theory-based work offers perspectives on IP integration within CP. Despite its geographic focus this work offers insights relevant to wider contexts on IP integration. It shows 'collective action' focused 'organisation' and 'group process' challenges with a need for further work on staff training, resource availability and utilisation, working relationships, communication and management

A highly osmotolerant rhizobial strain confers a better tolerance of nitrogen fixation and enhances protective activities to nodules of Phaseolus vulgaris under drought stress

The effect of water deficiency on nodules of common bean (Phaseolus vulgaris) inoculated with three rhizobial strains differing in their osmotolerance, was investigated in two different experiments on sterile sand. In the first experiment, the control plants were maintained at 90% field capacity (FC) and water-deficient plants were grown at 35% FC. The nitrogen fixation and growth parameters drastically decreased under water deficiency, however the three rhizobial strains, Rhizobium etli A32 (sensitive), Rhizobium tropici CIAT899 (tolerant), and Ensifer meliloti 4H41 (highly tolerant), showed different symbiotic performances. E. meliloti 4H41 allowed the best acetylene reduction activity (ARA) and biomass production and the highest number of large-sized nodules, while no significant effect was observed on lipid peroxidation, protein and legheamoglobin contents. The effect on antioxidant activities was the lowest. In the second experiment, plants were maintained at 90% FC during 45 days and then watering was stopped. The results showed that, the response to water deficit was quite similar for the three analyzed symbioses until 35% FC, but below this value of FC, symbiosis involving strain E. meliloti 4H41 was the most tolerant. This tolerance was accompanied, by in both experiments, by a stability of metabolic indices and protective antioxidant activities. These results suggest that, the relative tolerance of the nodules induced by strain 4H41 could be due to a constructive adaptation involving specific cortex structure and stress-adapted metabolic activities acquired during nodule formation and growth, rather than to a timely inducible response due to the stimulation of antioxidant enzymes. This suggestion should be confirmed through microscopic structure analysis and supplemental key enzymes in nodule metabolism such as sucrose synthase and malate dehydrogenase.Key words: Antioxidant activities, in pots experiment, leghemoglobin content, nodule, rhizobia, osmotolerance, symbiotic efficiency, water deficiency

Evaluation of the 2019 ACTp Pilot [Final Report]

In 2019, the first Additional Cost of Teaching Pharmacy (ACTp) funded experiential learning (EL) was piloted across Scotland. These pilots ran alongside existing EL in all years of the MPharm in two Scottish Schools of Pharmacy. Sixty undergraduate MPharm students participated in the pilot: 29 Robert Gordon University (RGU); 31 University of Strathclyde (UoS). A total of 41 sites hosted students, including 18 general practices, 10 community pharmacies, 10 community/specialist hospitals (e.g. mental health, prison service), NHS 24 (two sites) and one ‘combined package’. Two community pharmacies had extended opening and the eight remaining community pharmacies were in remote and rural locations. The sites were distributed across most of the Scottish Health Boards. This evaluation explored stakeholder opinions and experiences of the pilots and identified areas for future improvement

Exploration of inter-professional learning in experiential learning for student pharmacists in Scotland : a qualitative study

Abstract Introduction Additional Cost of Teaching for Pharmacy (ACTp) funding from Scottish Government supports the development of experiential learning (EL) placements for student pharmacists [1]. Interprofessional learning (IPL) has been built into initial education for many healthcare professionals [2]. In 2019, a National Pharmacy EL Stakeholder event recommended exploring the further development of IPL within EL for the MPharm. Aim To scope existing IPL in EL and explore the feasibility for further development within the MPharm in Scotland Methods Online qualitative interviews were conducted with key stakeholders from Schools of Pharmacy, NHS Education for Scotland, EL sites, and Scottish health boards. All were involved in the development/delivery of these activities. The interview schedule was developed by the research team, reviewed for face and content validity, piloted prior to use, and modified based on early interviews. All interviews were audio-recorded, transcribed, and independently thematically analysed by two researchers. Interviews continued until data saturation and good representation from all settings were achieved. All ethical approvals were sought prior to the interviews. Results Twenty interviews were conducted with three key themes emerging; (1)current IPL within EL activities, (2)future developments, and (3)perceptions of enablers and barriers to developing/delivering IPL within EL. There were limited examples of existing IPL within EL activities including: a pilot pharmacy longitudinal clerkship and hospital-based pharmacy/medical student IPL week. Some stakeholders indicated that current IPL involves mainly campus-based activities but other EL based initiatives were planned but not yet implemented. Respondents indicated that future developments should be carefully planned in collaboration with other stakeholders and tailored to students’ stage of study to ensure their success. There was significant support for incorporating IPL within EL initiatives as part of the MPharm course to complement traditional ways of teaching. “I think if we don't do it, we're missing a big trick… Doing something in a classroom or doing something within a small tutorial is a very false way of learning, whereas in practice, where they're going to end up working together, it seems ideal.” Many enablers were highlighted mainly relating to the expected benefits of such activities on students, facilitators, patients, and the healthcare system. Logistics and planning difficulties were perceived to be barriers to implementation of IPL within EL. “We've tried to do it, it was with the medical school and they were receptive to it, but the logistics just didn't work out… when you've got two very different timetables to try and bring together, it is very, very difficult to do.” Conclusion Pharmacy stakeholders highlighted that the majority of IPL currently undertaken in Scotland is not based in EL settings but they supported developing it. Enablers and barriers articulated highlight the need for careful planning of these activities. A strength of this study is it involved a broad range of key stakeholders from across Scotland ensuring representativeness of views and ideas. A limitation may be that, given the Scottish focus, findings may lack direct transferability to other countries. Future research should focus on designing a framework for developing and implementing IPL within EL in Scotland. References 1. NHS Education for Scotland, 2020. Experiential learning for student pharmacists in Scotland. [online]. Edinburgh: NHS Education for Scotland. Available from: https://www.nes.scot.nhs.uk/our-work/experiential-learning-for-student-pharmacists-in-scotland/ [Accessed 07/10/2020]. 2. Barr H. Interprofessional Education-The Genesis of Global Movement. 2015. https://www.caipe.org/resources/publications/barr-h-2015-interprofessional-education-genesis-global-movement. [Accessed 4 Aug 2020

The international literature underpinning collaborative practice within practice based experiential learning for the initial education of student pharmacists : a scoping review

Abstract Introduction Interprofessional team working within healthcare [1] enables the use of complementary areas of expertise. Collaborative practice (CP) builds on this and enhances recognition and respect for such expertise which facilitates professional synergy. Development of CP needs to be built into initial education programmes and there is global progress. [2] Further, a WHO Framework highlighted the importance of courses developing CP in experiential learning (EL) environments. [1] There is need to develop both CP and EL within pharmacy courses to meet governmental and regulatory aspirations around the clinical and prescribing roles of pharmacists. Aim The aim of this part of a scoping review was to describe the different characteristics of the international literature around the development, implementation and evaluation of CP within practice based EL for initial education of student pharmacists. Methods The six-stage Arksey and O'Malley framework and the PRISMA extension for Scoping Reviews for reporting were followed. Eligibility criteria were defined (Table 1) and electronic searches of relevant databases (Medline, IPA, CINAHL and Google Scholar) conducted from inception to April 2020. MeSH terms and other relevant subject headings and text words were used. First stage involved screening titles / abstracts and second stage involved review of full text articles. A charting tool was developed and used to extract data on: country, study design, methods of evaluation, sector of practice, stage of students, professional groups involved, monitoring and assessment and scope for development. Findings were presented as a descriptive narrative summary. All steps involved independent checks by two of the review team. Results Twenty-eight papers were included with most from the USA (16 papers), with the remainder from Australia (5 papers), UK (5 Papers), Canada and the Netherlands (1 paper each). The majority of papers described quantitative methods using a wide variety of published (some validated) scales (20 scales including RIPLS, SPICE, CPAT) and a number of bespoke survey tools. The main focus was at 'Kirkpatrick model of educational evaluation' level 3 – with 13 papers focussing on changes to professional behaviours. Papers focussed on either hospital (12 papers) or primary care initiatives (12 papers) with the remaining four describing cross-sectoral settings. Only 6 papers stated that they focussed on specific healthcare specialities and the remainder were in general medical facilities. The nature of initiatives and activities varied with a predominance of focus to include later years of study. Only 3 papers included only pharmacy and medicine students.. Detailed information was lacking on methods of student assessment: some reported this involved reflection, with limited reporting of tools to assess competencies. A wide array of further research proposals was articulated. Conclusion This scoping review highlights the range of work already carried out. The diversity highlights the need for consideration of commonality in the nature of activity and tools to evaluate outcomes to ensure transferability to practice. There are many challenges influencing further development and implementation of CP. Facilitating matters by using the evidence base to add to existing placements without restructuring curricula across courses / institutions has been proposed by some authors