title: Logistic regression and boosting for labeled bags of instances

authors: Xu, Xin

subjects: computer science

abstract: In this paper we upgrade linear logistic regression and boosting to multi-instance data, where each example consists of a labeled bag of instances. This is done by connecting predictions for individual instances to a bag-level probability estimate by simple averaging and maximizing the likelihood at the bag level—in other words, by assuming that all instances contribute equally and independently to a bags label. We present empirical results for artificial data generated according to the underlying generative model that we assume, and also show that the two algorithms produce competitive results on the Musk benchmark datasets.

text: Logistic regression and boosting for labeled bags of instances In this paper we upgrade linear logistic regression and boosting to multi-instance data, where each example consists of a labeled bag of instances. This is done by connecting predictions for individual instances to a bag-level probability estimate by simple averaging and maximizing the likelihood at the bag level—in other words, by assuming that all instances contribute equally and independently to a bags label. We present empirical results for artificial data generated according to the underlying generative model that we assume, and also show that the two algorithms produce competitive results on the Musk benchmark datasets.

year: 2004

title: A novel way to quantify schizophrenia symptoms in clinical trials

authors: Medvedev, Oleg N.

subjects: Clinical Trial

abstract: BACKGROUND: A major problem in quantifying symptoms of schizophrenia is establishing a reliable distinction between enduring and dynamic aspects of psychopathology. This is critical for accurate diagnosis, monitoring and evaluating treatment effects in both clinical practice and trials. 
MATERIALS AND METHODS: We applied Generalisability Theory, a robust novel method to distinguish between dynamic and stable aspects of schizophrenia symptoms in the widely used Positive and Negative Symptom Scale (PANSS) using a longitudinal measurement design. The sample included 107 patients with chronic schizophrenia assessed using the PANSS at five time points over a 24-week period during a multi-site clinical trial of N-Acetylcysteine as an add-on to maintenance medication for the treatment of chronic schizophrenia. 
RESULTS: The original PANSS and its three subscales demonstrated good reliability and generalisability of scores (G=0.77-0.93) across sample population and occasions making them suitable for assessment of psychosis risks and long-lasting change following a treatment, while subscales of the five factor models appeared less reliable. The most enduring symptoms represented by the PANSS were poor attention, delusions, blunted affect, and poor rapport. More dynamic symptoms with 40-50% of variance explained by patient transient state including grandiosity, preoccupation, somatic concerns, guilt feeling and hallucinatory behaviour. 
CONCLUSIONS: Identified dynamic symptoms are more amendable to change and should be the primary target of interventions aiming at effectively treating schizophrenia. Separating out the dynamic symptoms would increase assay sensitivity in trials, reduce the signal to noise ratio and increase the potential to detect the effects of novel therapies in clinical trials.

text: A novel way to quantify schizophrenia symptoms in clinical trials BACKGROUND: A major problem in quantifying symptoms of schizophrenia is establishing a reliable distinction between enduring and dynamic aspects of psychopathology. This is critical for accurate diagnosis, monitoring and evaluating treatment effects in both clinical practice and trials. 
MATERIALS AND METHODS: We applied Generalisability Theory, a robust novel method to distinguish between dynamic and stable aspects of schizophrenia symptoms in the widely used Positive and Negative Symptom Scale (PANSS) using a longitudinal measurement design. The sample included 107 patients with chronic schizophrenia assessed using the PANSS at five time points over a 24-week period during a multi-site clinical trial of N-Acetylcysteine as an add-on to maintenance medication for the treatment of chronic schizophrenia. 
RESULTS: The original PANSS and its three subscales demonstrated good reliability and generalisability of scores (G=0.77-0.93) across sample population and occasions making them suitable for assessment of psychosis risks and long-lasting change following a treatment, while subscales of the five factor models appeared less reliable. The most enduring symptoms represented by the PANSS were poor attention, delusions, blunted affect, and poor rapport. More dynamic symptoms with 40-50% of variance explained by patient transient state including grandiosity, preoccupation, somatic concerns, guilt feeling and hallucinatory behaviour. 
CONCLUSIONS: Identified dynamic symptoms are more amendable to change and should be the primary target of interventions aiming at effectively treating schizophrenia. Separating out the dynamic symptoms would increase assay sensitivity in trials, reduce the signal to noise ratio and increase the potential to detect the effects of novel therapies in clinical trials.

year: 2020

title: Street-level bureaucracy and occupational therapy practices in Aotearoa New Zealand. A genealogical critique.

authors: Silcock, Elizabeth Mary

subjects: power

abstract: As a human science that is also part of administering and supporting bureaucracy, occupational therapy functions in multi-layered networks of power  that support many different social structures. Occupational therapists’ work often involves operationalising health, education and social services at the street-level, positioning them between the aspirations of both policy and social activism and material life outcomes. Through a genealogical critique, this thesis problematises the practice of occupational therapy through a Foucauldian lens that views everything as dangerous. By viewing occupational therapy practice as dangerous, the power relations at the street-level of the mundane and taken-for-granted have been problematised as part of much larger social structures of power and discourse. 
Several Foucauldian tools were deployed in order to ensure that a focus on occupational therapy practices was maintained; three distinct research methods were utilised to access a range of heterogeneous genealogical information.  Firstly, an historical archival analysis of the four iterations of the Competencies for Registration for occupational therapists document (1990 to the current day) produced by the regulatory authority, the Occupational Therapy Board of New Zealand, was carried out.  Secondly, practice observations of occupational therapists working in different practice settings were analysed as three individual case studies. Concurrently with these two methods, a critical action method using a research blog was developed to create a medium for public discussion of practice through an open engagement with the profession. The combination of these three methods enabled access to a range of elements for analysis.  Many of these elements inter-linked, overlapped and connected to historically contingent networks of dominant power that have formed through the processes of colonisation, the establishment of the health system and normalised medical practices, and economic forms of governance. The nuances of how occupational therapy is practised at the street-level offered opportunities to contest the dominance of these networks. In all three case studies there was an unspoken understanding and a normalisation of materiality as an accepted and significant element of how the profession practised.  The material regimes of knowledge and material practices in these unspoken norms were highly productive and able to contest other lines of power.  Along with this alternate network of power, the most recent version of the Competencies for Registration offers a further opportunity for occupational therapists to contest dominant power relations in a way that could capitalise on the secure position the profession has developed through its material network of power.  Opportunities for alternate pathways of practice which privilege Te Ao Māori and Te Tiriti o Waitangi are a possibility in the legally sanctioned Competencies. The close connection of occupational therapy practices to real life material outcomes for other people, position the street-level doing of occupational therapists at a juncture where action and decision making can re-configure power relations. Re-thinking practice in terms of what the doing of occupational therapy does in relation to networks of power, is an opportunity for practitioners to enact policy at the street-level in ways that use their ability to influence power from the bottom up whilst being alert to the dangers presented by doing so.

text: Street-level bureaucracy and occupational therapy practices in Aotearoa New Zealand. A genealogical critique. As a human science that is also part of administering and supporting bureaucracy, occupational therapy functions in multi-layered networks of power  that support many different social structures. Occupational therapists’ work often involves operationalising health, education and social services at the street-level, positioning them between the aspirations of both policy and social activism and material life outcomes. Through a genealogical critique, this thesis problematises the practice of occupational therapy through a Foucauldian lens that views everything as dangerous. By viewing occupational therapy practice as dangerous, the power relations at the street-level of the mundane and taken-for-granted have been problematised as part of much larger social structures of power and discourse. 
Several Foucauldian tools were deployed in order to ensure that a focus on occupational therapy practices was maintained; three distinct research methods were utilised to access a range of heterogeneous genealogical information.  Firstly, an historical archival analysis of the four iterations of the Competencies for Registration for occupational therapists document (1990 to the current day) produced by the regulatory authority, the Occupational Therapy Board of New Zealand, was carried out.  Secondly, practice observations of occupational therapists working in different practice settings were analysed as three individual case studies. Concurrently with these two methods, a critical action method using a research blog was developed to create a medium for public discussion of practice through an open engagement with the profession. The combination of these three methods enabled access to a range of elements for analysis.  Many of these elements inter-linked, overlapped and connected to historically contingent networks of dominant power that have formed through the processes of colonisation, the establishment of the health system and normalised medical practices, and economic forms of governance. The nuances of how occupational therapy is practised at the street-level offered opportunities to contest the dominance of these networks. In all three case studies there was an unspoken understanding and a normalisation of materiality as an accepted and significant element of how the profession practised.  The material regimes of knowledge and material practices in these unspoken norms were highly productive and able to contest other lines of power.  Along with this alternate network of power, the most recent version of the Competencies for Registration offers a further opportunity for occupational therapists to contest dominant power relations in a way that could capitalise on the secure position the profession has developed through its material network of power.  Opportunities for alternate pathways of practice which privilege Te Ao Māori and Te Tiriti o Waitangi are a possibility in the legally sanctioned Competencies. The close connection of occupational therapy practices to real life material outcomes for other people, position the street-level doing of occupational therapists at a juncture where action and decision making can re-configure power relations. Re-thinking practice in terms of what the doing of occupational therapy does in relation to networks of power, is an opportunity for practitioners to enact policy at the street-level in ways that use their ability to influence power from the bottom up whilst being alert to the dangers presented by doing so.

year: 2018