Multivariate analysis for animal selection in experimental research

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Multivariate analysis for selecting animals for experimental research

Background Several researchers seek methods for the selection of homogeneous groups of animals in experimental studies, a fact justified because homogeneity is an indispensable prerequisite for casualization of treatments. The lack of robust methods that comply with statistical and biological principles is the reason why researchers use empirical or subjective methods, influencing their results. Objective To develop a multivariate statistical model for the selection of a homogeneous group of animals for experimental research and to elaborate a computational package to use it. Methods The set of echocardiographic data of 115 male Wistar rats with supravalvular aortic stenosis (AoS) was used as an example of model development. Initially, the data were standardized, and became dimensionless. Then, the variance matrix of the set was submitted to principal components analysis (PCA), aiming at reducing the parametric space and at retaining the relevant variability. That technique established a new Cartesian system into which the animals were allocated, and finally the confidence region (ellipsoid) was built for the profile of the animals’ homogeneous responses. The animals located inside the ellipsoid were considered as belonging to the homogeneous batch; those outside the ellipsoid were considered spurious. Results The PCA established eight descriptive axes that represented the accumulated variance of the data set in 88.71%. The allocation of the animals in the new system and the construction of the confidence region revealed six spurious animals as compared to the homogeneous batch of 109 animals. Conclusion The biometric criterion presented proved to be effective, because it considers the animal as a whole, analyzing jointly all parameters measured, in addition to having a small discard rate.

Impact of the Level of Disclosure of Financial Information on the Pricing of Shares in the Context of Adverse Selection: an experimental research

Managers know more about the performance of the organization than investors, which makes the disclosure of information a possible strategy for competitive differentiation, minimizing adverse selection. This paper's main goal is to analyze whether or not an entity's level of diclosure may affect the risk perception of individuals and the process of evaluating their shares. The survey was carried out in an experimental study with 456 subjects. In a stock market simulation, we investigated the pricing of the stocks of two companies with different levels of information disclosure at four separate stages. The results showed that, when other variables are constant, the level of disclosure of an entity can affect the expectations of individuals and the process of evaluating their shares. A higher level of disclosure by an entity affected the value of its share and the other company's.

Experimental research on the residual mechanical properties of an ordinary concretes after fire

This paper summarizes the results of an experimental research to assess the residual mechanical properties of an ordinary concrete after fire. It was studied the influence of the cooling process, the maximum temperature that the concrete was subjected to and the loading level on the residual mechanical properties of calcareous and granite aggregate concretes. The properties studied were the residual compressive, tensile, splitting and flexural strengths and modulus of elasticity. Four levels of temperature; 20, 300, 500 and 700ºC; two loading levels (0.3f and 0.7fcd) and two cooling processes (cooling in the air and by water jet) were tested. The high temperatures attained and the sudden cooling down process on the concrete showed a negative effect on its residual mechanical properties. This effect was more notorious on the residual compression strength than in the other mechanical properties

Proceedings of the Conference on Experimental Research in Computer Systems /

"NSF workshop."--Cover.

The physiology and pathology of the cerebral circulation; an experimental research,

Mode of access: Internet.

An experimental research design for the modified operational program design for Minnesota's Work Equity Program /

"Draft."

Scaling up experimental ocean acidification and warming research: from individuals to the ecosystem

Understanding long-term, ecosystem-level impacts of climate change is challenging because experimental research frequently focuses on short-term, individual-level impacts in isolation. We address this shortcoming first through an inter-disciplinary ensemble of novel experimental techniques to investigate the impacts of 14-month exposure to ocean acidification and warming (OAW) on the physiology, activity, predatory behaviour and susceptibility to predation of an important marine gastropod (Nucella lapillus). We simultaneously estimated the potential impacts of these global drivers on N. lapillus population dynamics and dispersal parameters. We then used these data to parameterise a dynamic bioclimatic envelope model, to investigate the consequences of OAW on the distribution of the species in the wider NE Atlantic region by 2100. The model accounts also for changes in the distribution of resources, suitable habitat and environment simulated by finely resolved biogeochemical models, under three IPCC global emissions scenarios. The experiments showed that temperature had the greatest impact on individual level responses, while acidification has a similarly important role in the mediation of predatory behaviour and susceptibility to predators. Changes in Nucella predatory behaviour appeared to serve as a strategy to mitigate individual level impacts of acidification, but the development of this response may be limited in the presence of predators. The model projected significant large-scale changes in the distribution of Nucella by the year 2100 that were exacerbated by rising greenhouse gas emissions. These changes were spatially heterogeneous, as the degree of impact of OAW on the combination of responses considered by the model varied depending on local environmental conditions and resource availability. Such changes in macro-scale distributions cannot be predicted by investigating individual level impacts in isolation, or by considering climate stressors separately. Scaling up the results of experimental climate change research requires approaches that account for long-term, multi-scale responses to multiple stressors, in an ecosystem context.

Scaling up experimental ocean acidification and warming research: from individuals to the ecosystem

Understanding long-term, ecosystem-level impacts of climate change is challenging because experimental research frequently focuses on short-term, individual-level impacts in isolation. We address this shortcoming first through an inter-disciplinary ensemble of novel experimental techniques to investigate the impacts of 14-month exposure to ocean acidification and warming (OAW) on the physiology, activity, predatory behaviour and susceptibility to predation of an important marine gastropod (Nucella lapillus). We simultaneously estimated the potential impacts of these global drivers on N. lapillus population dynamics and dispersal parameters. We then used these data to parameterise a dynamic bioclimatic envelope model, to investigate the consequences of OAW on the distribution of the species in the wider NE Atlantic region by 2100. The model accounts also for changes in the distribution of resources, suitable habitat and environment simulated by finely resolved biogeochemical models, under three IPCC global emissions scenarios. The experiments showed that temperature had the greatest impact on individual level responses, while acidification has a similarly important role in the mediation of predatory behaviour and susceptibility to predators. Changes in Nucella predatory behaviour appeared to serve as a strategy to mitigate individual level impacts of acidification, but the development of this response may be limited in the presence of predators. The model projected significant large-scale changes in the distribution of Nucella by the year 2100 that were exacerbated by rising greenhouse gas emissions. These changes were spatially heterogeneous, as the degree of impact of OAW on the combination of responses considered by the model varied depending on local environmental conditions and resource availability. Such changes in macro-scale distributions cannot be predicted by investigating individual level impacts in isolation, or by considering climate stressors separately. Scaling up the results of experimental climate change research requires approaches that account for long-term, multi-scale responses to multiple stressors, in an ecosystem context.

Practice-led research and the innovation agenda : beyond the postgraduate research degree in the arts, design and media

The rise of the ‘practice-led’ research approach has given us a new way of understanding what creative practice in art, design and media can do in the academy and the world— it can materialise new ideas and forms into being as a form of experimental research. Yet, to date, attention around the world, and especially in Australia, has been chiefly directed at the postgraduate research degrees, most notably the PhD or doctoral equivalents. Recent mapping projects and surveys of practice-led research in Australia reveal much about the institutional conditions of higher degree researchers, supervisors, examiners and research training (Baker et al 2009; Evans et al 2003; Dally et al 2004; Paltridge et al 2009; Phillips et al 2009). Given this focus, we might well ask: is the practice-led approach destined to be a part of the higher degree ghetto only, or does it have an afterlife? What is the place of ‘practice-led’ beyond the postgraduate degree? After all postgraduate researchers do not remain postgraduates forever, and perhaps the practice-led approach to research may have benefits in wider university, professional and communal contexts.

Nurse-led telephone interventions for people with cardiac disease : A review of the research literature

Background: Nurse-led telephone follow-up offers a relatively inexpensive method of delivering education and support for assisting recovery in the early discharge period; however, its efficacy is yet to be determined. Aim: To perform a critical integrative review of the research literature addressing the effectiveness of nurse-led telephone interventions for people with coronary heart disease (CHD). Methods: A literature search of five health care databases; Sciencedirect, Cumulative Index to Nursing and Allied Health Literature, Pubmed, Proquest and Medline to identify journal articles between 1980 and 2009. People with cardiac disease were considered for inclusion in this review. The search yielded 128 papers, of which 24 met the inclusion criteria. Results: A total of 8330 participants from 24 studies were included in the final review. Seven studies demonstrated statistically significant differences in all outcomes measured, used two group experimental research design and valid and reliable instruments. Some positive effects were detected in eight studies in regards to nurse-led telephone interventions for people with cardiac disease and no differences were detected in nine studies. Discussion: Studies with some positive effects generally had stronger research designs, large samples, used valid and reliable instruments and extensive nurse-led educative interventions. Conclusion: The results suggest that people with cardiac disease showed some benefits from nurse-led/delivered telephone interventions. More rigorous research into this area is needed.

Systematic literature review: Research on Supported Playgroups

Overview This review of research conducted with supported playgroups was prepared for the Queensland Department of Education, Training and Employment (DETE). The report provides a synthesis of the research on the effectiveness of supported playgroups to improve child, parent, and community outcomes and to identify key features of supported playgroups that support effective outcomes. Supported playgroups are community-based services that provide a low intensity parenting intervention, through regular group sessions for parent-child dyads. Supported playgroups target vulnerable families who may benefit from parenting support. Supported playgroups have common goals to enhance children’s early learning and parental wellbeing. Method A search strategy was devised to identify research studies, nationally and internationally, that involved parent-child group programs for families with young children, delivered under the leadership of an employed facilitator. Academic databases and other data sources were explored for studies conducted in the period from 2004 to 2014. Summary descriptions of the research studies were developed; assessment of research methodologies was made; research evidence on the effectiveness of supported playgroups to improve child, parent, and community outcomes was identified; and comparative analyses of the implementation features of supported playgroups were completed. Findings The search strategy identified 34 research publications, reporting on 29 different programs. Twenty-six of the studies report on research conducted in Australia and eight reported on research conducted in other countries, including the United Kingdom, Canada, and the United States. Three clusters of playgroups were identified: Category 1 - Standard supported playgroups; Category 2 - Mobile playgroups; Category 3 – Supported playgroups with specific interventions. The research studies identified encompassed experimental and non-experimental research designs. The studies of standard supported playgroups and mobile playgroups were most often qualitative studies and modest in scale, in terms of the number of research participants. Experimental and quasi-experimental research designs characterised the studies identified in the category of supported playgroups with specific interventions. Overall, the research studies that were categorised as supported playgroups with specific interventions provided stronger evidence for effectiveness to improve parental behaviour in ways that are known to support children’s early developmental competence. Qualitative studies, including case studies and ethnographic research, documented important features of program delivery, such as the importance of facilitators’ interpersonal skills to positive experiences for families in the playgroups; as well as the important opportunities that the playgroups afforded to vulnerable families to reduce social isolation. Conclusions The potential for supported playgroups to improve a broad range of learning and psychosocial outcomes for children and parents was suggested by many of the research studies. However, the nature of the research designs employed means that it is not possible to conclude that there is strong evidence of the impact of supported playgroups on child, parent, and community outcomes. The qualitative studies did provide rich descriptions about the implementation processes of playgroups and also captured the variability in the delivery of the playgroups in terms of who participated, local contextual factors that impacted on the playgroup experiences, and the nature of the experiences of parents within the playgroups. Research methodologies need to be employed that address the limitations of the studies to date. This would provide more defensible evidence that supported playgroups have an impact over time on outcomes for children, families, and communities. Overall, this area of research remains relatively under-evaluated in terms of rigorous research designs. The identified research studies point to some promising research directions but do not yet enable strong claims to be made about the effectiveness of the standard playgroup or mobile playgroup models to impact on parenting outcomes. Data collected from interview and survey methodologies clearly identifies that supported playgroups are highly acceptable to families. Given the popularity of supported playgroups to engage families across diverse communities, and the reported high levels of satisfaction and benefits identified within many of the research studies, it is clear that the provision of supported playgroups is fulfilling an important community need by providing support to parents with young children. However, there is a need to strengthen the evidence base that supported playgroups are an effective early parenting intervention that improves outcomes for children, parents, and communities.