Ce bullying in schools in the U.S. on levels of Naramycin A solubility homophobia and risk behaviors among adolescent MSM. Another example is to study reproductive health clinics in high schools, both upstream on the macro level by examining the political systems and actors that lead to the establishment of the clinics, and downstream, at the meso and micro levels, by focusing on teachers’ and students’ attitudes about the clinics and condom use norms and practices. The second approach includes examining the existing distribution of macro- and meso-level factors that may influence HIV prevention behaviors. For example, the number of gay bars varies by urban area and may influence sexual mixing patterns and risk behaviors. The assessment of differences in syringe access laws by jurisdiction and HIV rates is an example of the impact of structural level factors on HIV risk behaviors.99 In the U.S., some states had less restrictive syringe access laws before the HIV epidemic. Others changed their laws in Cynaroside price response to HIV, and some were highly resistant to increase syringe access even in the face of the HIV epidemic. There are many opportunities to study the dynamic influences of structural factors on HIV risk behaviors using this approach. Natural disturbances in systems such as new laws and law enforcement practices may lead to alterations in settings, resource allocations, and social configurations. The establishment of drug courts, legalization of gay marriages, and changes in legislation for syringe access may alter systems that lead to changes in HIV prevention behaviors. Moreover, even the same laws are often not simultaneously implemented in all jurisdictions, and there is often latitude in how they are implemented. Common measures across jurisdictions may allow for comparisons of the impact of laws and policies and their implementation. Basic research on structural factors and dynamics represented by these first two approaches comes with significant theoretical challenges. One is the complexity and “immensity” of structural factors (i.e., their social distance from the individual and his/her ability to affect them), and the difficulty of distilling and/or unpacking key components on multiple levels that are hypothesized as most relevant to the particular question. The matrix of multilevelAIDS Behav. Author manuscript; available in PMC 2011 December 1.NIH-PA Author Manuscript NIH-PA Author Manuscript NIH-PA Author ManuscriptLatkin et al.Pagestructural factors in our model represents the possible arenas to consider in building theory related to a specific problem; but not all arenas are relevant in each case. This complexity also makes it challenging to identify achievable actions to change these structural forces and constraints. Yet another problem is the difficulty both of conceptualizing the relationships between levels of structural factors, including their relationships with the individual level, and effecting change on these levels or on their hypothesized relationships. Applying dynamic systems theory to test relationships among components of structural factors on multiple levels and testing multiple pathways in their relationships to individuals provides a means to organize and reduce this complexity and examine avenues of intervention. The third approach to structural research on the HIV epidemic is to involve researchers in both the implementation and evaluation of structural interventions that have the explicit goal of reducing HIV risk behaviors.Ce bullying in schools in the U.S. on levels of homophobia and risk behaviors among adolescent MSM. Another example is to study reproductive health clinics in high schools, both upstream on the macro level by examining the political systems and actors that lead to the establishment of the clinics, and downstream, at the meso and micro levels, by focusing on teachers’ and students’ attitudes about the clinics and condom use norms and practices. The second approach includes examining the existing distribution of macro- and meso-level factors that may influence HIV prevention behaviors. For example, the number of gay bars varies by urban area and may influence sexual mixing patterns and risk behaviors. The assessment of differences in syringe access laws by jurisdiction and HIV rates is an example of the impact of structural level factors on HIV risk behaviors.99 In the U.S., some states had less restrictive syringe access laws before the HIV epidemic. Others changed their laws in response to HIV, and some were highly resistant to increase syringe access even in the face of the HIV epidemic. There are many opportunities to study the dynamic influences of structural factors on HIV risk behaviors using this approach. Natural disturbances in systems such as new laws and law enforcement practices may lead to alterations in settings, resource allocations, and social configurations. The establishment of drug courts, legalization of gay marriages, and changes in legislation for syringe access may alter systems that lead to changes in HIV prevention behaviors. Moreover, even the same laws are often not simultaneously implemented in all jurisdictions, and there is often latitude in how they are implemented. Common measures across jurisdictions may allow for comparisons of the impact of laws and policies and their implementation. Basic research on structural factors and dynamics represented by these first two approaches comes with significant theoretical challenges. One is the complexity and “immensity” of structural factors (i.e., their social distance from the individual and his/her ability to affect them), and the difficulty of distilling and/or unpacking key components on multiple levels that are hypothesized as most relevant to the particular question. The matrix of multilevelAIDS Behav. Author manuscript; available in PMC 2011 December 1.NIH-PA Author Manuscript NIH-PA Author Manuscript NIH-PA Author ManuscriptLatkin et al.Pagestructural factors in our model represents the possible arenas to consider in building theory related to a specific problem; but not all arenas are relevant in each case. This complexity also makes it challenging to identify achievable actions to change these structural forces and constraints. Yet another problem is the difficulty both of conceptualizing the relationships between levels of structural factors, including their relationships with the individual level, and effecting change on these levels or on their hypothesized relationships. Applying dynamic systems theory to test relationships among components of structural factors on multiple levels and testing multiple pathways in their relationships to individuals provides a means to organize and reduce this complexity and examine avenues of intervention. The third approach to structural research on the HIV epidemic is to involve researchers in both the implementation and evaluation of structural interventions that have the explicit goal of reducing HIV risk behaviors.