BIOT 1012: Research Methods

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Questions and Answers

How does the isolation of tissues or organs in Ex-vivo studies impact control over experimental conditions compared to In-vivo studies?

Ex-vivo studies offer greater control over experimental conditions compared to In-vivo studies because the tissue or organ is isolated, allowing for more controlled manipulation and observation.

What key ethical consideration distinguishes In-vivo studies from In-vitro studies?

In-vivo studies often raise more significant ethical concerns, particularly regarding animal welfare and human subject rights, compared to in-vitro studies, which typically involve fewer ethical considerations if using cell lines or non-human cells.

In what way do the ethical considerations typically differ between In-vivo and In-vitro studies, particularly concerning the use of cell lines?

In-vivo studies often involve significant ethical considerations related to animal or human subjects. In-vitro studies typically involve fewer ethical concerns, especially when using cell lines or non-human cells.

How might a researcher adjust data analysis techniques in response to the limitations of an In-vitro model compared to an In-vivo model?

Researchers might use simpler statistical methods or focus on effect sizes in In-vitro studies, whereas In-vivo studies may require more complex modeling to account for biological variability and interactions. Signup and view all the answers

Explain the trade-off between biological relevance and experimental control when choosing between In-vivo and In-vitro studies.

In-vivo studies offer high biological relevance but limited experimental control, while In-vitro studies provide high experimental control at the cost of reduced biological relevance. Signup and view all the answers

What are the key reasons for using animal models that are genetically engineered in disease studies?

Genetically engineered animal models are used because they help in mimicking human diseases such as cancer, diabetes, and neurological disorders, allowing researchers to study disease mechanisms and test potential therapies. Signup and view all the answers

Explain how transmission studies influence the choice of a research model (In-vivo, In-vitro, or Ex-vivo).

Transmission studies often necessitate the use of In-vivo models to observe the spread of a pathogen or disease within a whole organism, which cannot be replicated in In-vitro or Ex-vivo systems. Signup and view all the answers

How does the potential for ethical concerns in research influence the selection between In-vivo and In-vitro experimental designs?

The presence of potential ethical concerns may lead researchers to favor In-vitro designs over In-vivo designs to minimize harm to living organisms, particularly in preliminary studies. Signup and view all the answers

How does the complexity of interactions within a biological system affect the decision to use an In-vivo versus an In-vitro model?

If the research question requires studying complex interactions within a whole organism, an In-vivo model is preferable; if the focus is on isolating specific cellular or molecular mechanisms, an In-vitro model is more appropriate. Signup and view all the answers

What role does similarity to human physiology and metabolism play in the selection of a species for In-vivo studies?

Species with metabolic pathways and physiological responses similar to humans (e.g. primates) are preferred for In-vivo studies to improve the translatability of results to human health. Signup and view all the answers

What is the primary goal of hypothesis-driven research, and how does it contrast with hypothesis-generating research?

The primary goal of hypothesis-driven research is to confirm or reject a pre-existing hypothesis, whereas hypothesis-generating research aims to identify new patterns or relationships that can form the basis of future hypotheses. Signup and view all the answers

Explain how the volume and type of data output typically differ between hypothesis-generating and hypothesis-driven research approaches.

Hypothesis-generating research often produces large, omics-based datasets aimed at discovering novel patterns, while hypothesis-driven research tends to generate targeted, smaller datasets focused on specific variables. Signup and view all the answers

Describe how the ex-vivo model using human lung tissue explants helps researchers to study cell-cell communication during viral infections.

The ex-vivo model uses human lung tissue to maintain the integrity of lung cells and their interactions. This enables researchers to directly observe cell-cell communication in a system that closely mimics the natural lung environment during a viral infection. Signup and view all the answers

What is a key limitation of cross-sectional studies in establishing causal relationships?

Cross-sectional studies capture data at a single point in time, making it impossible to determine the temporal sequence of events and thus establish causality between variables. Signup and view all the answers

In case-control studies, how does an odds ratio greater than 1 ($OR > 1$) typically inform the relationship between a risk factor and a disease?

An odds ratio greater than 1 in case-control studies suggests that exposure to a particular risk factor is associated with a higher odds of having the disease. Signup and view all the answers

Describe the key distinction between ecological studies and case-control studies in terms of the level at which data, results, and conclusions are applied.

Ecological studies apply data, results, and conclusions at the population level, while case-control studies focus on individual-level comparisons between cases and controls. Signup and view all the answers

How does the selection of participants differ between cohort and case-control studies, particularly in relation to the outcome of interest?

Cohort studies select participants based on exposure status, following them to observe outcomes, whereas case-control studies select participants based on outcome status (cases and controls) and then investigate prior exposures. Signup and view all the answers

How do cohort studies address the issue of temporality, which is often a limitation in cross-sectional studies?

Cohort studies establish temporality by following participants over time, allowing researchers to determine whether exposure precedes the outcome, thus supporting stronger inferences about causation. Signup and view all the answers

What is a key advantage of matched-pair designs in experimental studies, and how does it enhance the validity of the study?

A key advantage of matched-pair designs is the control for individual variation by comparing treatments within the same unit, reducing confounding and increasing the precision of the study. Signup and view all the answers

In the context of experimental design, what differentiates a completely randomized experiment from a randomized block design?

In a completely randomized experiment, units are randomly assigned to treatment groups without any restrictions, whereas a randomized block design first divides units into homogenous blocks before random assignment to treatment groups within those blocks. Signup and view all the answers

What is the main purpose of 'blocking' in an experimental design, and how does it help to reduce experimental error?

The main purpose of blocking is to reduce experimental error by accounting for known sources of variability. This is done by comparing results within blocks. Signup and view all the answers

How does 'randomization' help to eliminate bias in experimental designs?

Randomization helps to eliminate bias by ensuring that each experimental unit has an equal chance of being assigned to any treatment group, thus distributing known and unknown confounders evenly across groups. Signup and view all the answers

Describe a scenario where a quasi-experimental study design would be more appropriate than a randomized controlled trial.

A quasi-experimental study would be more appropriate than a randomized controlled trial when random assignment is not feasible or ethical, such as comparing the effects of different interventions on pre-existing groups. Signup and view all the answers

Explain how the application of statistical analyses and data handling techniques is influenced by the choice of experimental design.

Experimental design dictates the type of data generated, comparison groups, assumptions made, type of statistical test and types of relationships that need to be tested, thereby directly guiding the selection of appropriate statistical methods and data handling techniques. Signup and view all the answers

What is the primary goal of replication in experimental design, and how does it contribute to the reliability of results?

The primary goal of replication is to increase the statistical power of a study and to improve the reliability of results by providing multiple independent observations for each treatment, reducing the impact of random variation. Signup and view all the answers

How does the presence of confounders affect the interpretation of results in observational studies compared to designed experiments?

In observational studies, confounders can lead to spurious associations, making it difficult to determine true causal relationships, while designed experiments aim to control for or eliminate confounders through techniques like randomization and matching, improving the reliability of causal inferences. Signup and view all the answers

Describe the key characteristics of single and double-blinded experiments. How do those characteristics relate to minimized bias?

In single-blinded experiments, participants don't know their assigned group, but researchers do. In double blinded experiments, neither participants nor researchers know the assignments. This reduces bias by minimizing participant expectation effects and researcher bias in observation and data collection. Signup and view all the answers

For what kind of experiment would a 'washout' period be most critical? What purpose does the washout serve?

A washout period is most critical in crossover experiments with human or animal subjects. The washout serves to eliminate any residual effects of a previous treatment before a new treatment is administered, ensuring that results are only influenced by the current treatment. Signup and view all the answers

Describe how 'factorial design' allows researchers to examine multiple independent variables at the same time.

Factorial design allows researchers to simultaneously study the effects of two or more independent variables (factors) and their interactions by testing all possible combinations of the levels of these factors. This is more efficient than testing each variable separately. Signup and view all the answers

In a study testing a new vaccine, explain why researchers might choose to use a randomized controlled trial instead of simply observing the health outcomes of people who voluntarily get vaccinated.

Researchers use a randomized controlled trial rather than observing volunteers to control for confounders and biases, ensuring that any observed effects are due to the vaccine and not other factors like health behaviors or pre-existing conditions. Signup and view all the answers

In brief, explain the goal of statistical analysis.

The goal of statistical analysis is to determine whether the results of the study are likely to represent a real effect, or whether they are likely to have arisen by chance. Signup and view all the answers

What are the typical 'levels' for the variable 'Drug' in a study that compares a drug to a placebo?

The variable 'Drug' in a study comparing a drug to a placebo would have two levels: 'Drug' and 'Placebo'. Signup and view all the answers

Explain how a 'control' group is typically used in a designed experiment.

A control group is a group of individuals that do not receive the treatment. This group serves as a baseline against which the experimenter can compare the treated subjects. Signup and view all the answers

If you were designing a study to see if a new fertilizer can improve crop yield, what would be a good 'control' treatment?

For the fertilizer experiment, a good control treatment would be to grow crops using no fertilizer (or, perhaps the 'standard' fertilizer) and compare the yield to that of the new fertilizer. Signup and view all the answers

Thinking about the 'COVID-19 vaccine trial' scenario in the slides, why should the scientists ensure proper labeling of the samples collected?

In a COVID-19 vaccine trial proper labeling ensures that the tracking ensures that data is correctly associated with the correct individuals and their assigned groups (vaccinated vs. placebo), which is crucial for accurate and reliable data analysis. Signup and view all the answers

Thinking about the 'COVID-19 vaccine trial' scenario in the slides, why is it important for the number of individuals in each experimental group to be approximately equal?

In a vaccine experiment, having an equal number of individuals in treated and in control groups can support a more valid analysis. If one group or another is significantly larger, certain statistical calculations can be difficult or impossible. Signup and view all the answers

Name two study designs that do not feature randomization.

Ecological studies and Cross-sectional studies do not feature randomization. Signup and view all the answers

What kind of studies are best addressed with animal models and what are their limitations?

Animal models are best for transmission studies but there may be an issue if a specific animal is suitable or not, for example, metabolism in humans is different from that of animals. Signup and view all the answers

What are the components of the experiment?

The components of the experiment are the experimental unit, the treatment, the factor and the variable. Signup and view all the answers

Flashcards

Research

A process to investigate a question or solve a problem in a structured and systematic way.

Hypothesis

A tentative explanation for a phenomenon, used as a basis for further investigation.

In-vivo

Research conducted within a whole, living organism, allowing complex interactions to be observed.

In-vitro

Research conducted in a laboratory setting using components of an organism, such as cells or tissues.