CONTINUOUS-TIME FILTERS FOR STATE ESTIMATION FROM POINT PROCESS MODELS OF NEURAL DATA

Neural spike trains, the primary communication signals in the brain, can be accurately modeled as point processes. For many years, significant theoretical work has been done on the construction of exact and approximate filters for state estimation from point process observations in continuous-time. We have previously developed approximate filters for state estimation from point process observations in discrete-time and applied them in the study of neural systems. Here, we present a coherent framework for deriving continuous-time filters from their discrete-counterparts. We present an accessible derivation of the well-known unnormalized conditional density equation for state evolution, construct a new continuous-time filter based on a Gaussian approximation, and propose a method for assessing the validity of the approximation following an approach by Brockett and Clark. We apply these methods to the problem of reconstructing arm reaching movements from simulated neural spiking activity from the primary motor cortex. This work makes explicit the connections between adaptive point process filters for analyzing neural spiking activity in continuous-time, and standard continuous-time filters for state estimation from continuous and point process observations.     

System dynamics: Portraying bounded rationality

This paper examines the linkages between system dynamics and the Carnegie School in their treatment of human decision making. It is argued that the structure of system dynamics models implicitly assumes bounded rationality in decision making and that recognition of this assumption would aid system dynamicists in model construction and in communication with other social science disciplines. The paper begins by examining Simon's ‘principle of bounded rationality’ which draws attention to the cognitive limitations on the information gathering and processing powers of human decision makers. Forrester's ‘Market Growth Model’ is used to illustrate the central theme that system dynamics models are portrayals of bounded rationality. Close examination of the model formulation reveals decision functions involving simple rules of thumb and limited information content. Finally, there is a discussion of the implications of Carnegie philosophy for system dynamics as it affects communication, model structuring, model analysis and future research.     

How PSA’s Inclusion Shift Cracked the Ivory Tower Culture and Led to New Governance Challenges

PSA’s shift to inclusion began in the 1990s as a response to the declining membership and the domination of the association by scholars from the Ivory Tower universities--those institutions focusing primarily upon research. Cracking the Ivory Tower refers to this inclusion which involved encouraging student participation; inviting faculty from teaching-focused colleges; expanding program topics on teaching or issues of gender, race, sexual orientation; hosting inclusive receptions; and electing some officers from non-elite schools. As inclusion has dramatically increased membership and promoted more representative participation, governance now faces new challenges, especially the executive director's workload.     

Social Capital: An Interdisciplinary Concept*

Abstract This paper sets forth an interdisciplinary interpretation of social capital that will permit the concept to be used with precision in scholarly and scientific work. If the interpretation is accepted, the social capital concept cannot be regarded as a social theory, nor as a statement of normative goals. The interdisciplinary concept proposed here is applied to rural studies.     

Protective indigenous collective value of Ubuntu and child neglect: Implications for rural child protection practice

Theories on collective efficacy and social support suggest that indigenous values that support collective practices and sanction community obligations to childcare would be protective against child neglect. Likewise, new qualitative findings show that collective values are stronger in rural areas than in urban. This study tested the claims that the value of Ubuntu, which is a symbolic cultural value of ‘being for others’, will be protective against the likelihood of neglect; this relationship will be stronger in rural compared with urban communities in Ghana. Using data obtained from a nationally representative sample of 1100 mothers (from 22 communities) in Ghana, we tested the claims using fixed effects logistic regression. The Ubuntu norms were significantly endorsed in rural communities compared with the urban. The overall model showed that higher levels of Ubuntu are associated with lower odds of child neglect (OR .47, [.29, .76] p < 0.05), and the relationship remained significant only in the rural sample (OR .13, [.06, .31] p < 0.001). Similar evidence was recorded for the Ubuntu norms of community care and compassion. The results suggest that child protection in rural Ghana can be fruitful when interventions are developed to boost the value of Ubuntu and the norms of collective childcare.     

Marriage market imbalances and labor force participation of Canadian women

Several studies find a negative correlation between the ratio of males to females and measures of female labor supply in the US. This negative correlation has been interpreted as empirical support for the hypothesis that marriage market conditions influence intra-household allocation decisions. Given the similarity of cultures and of labor supply behavior of women in Canada and the United States, and the fact that they both experienced baby-booms at roughly the same time, any explanation for changes in female labor supply would be expected to hold for both countries. We test the prediction that marriage market conditions have explanatory power for Canadian female labor force participation (LFP) rates over the period 1971–2001. We find smaller marriage market effects for Canada than those found for the US but similar in magnitude to those found for the US Midwest.

Measuring policy entitlements at the micro-level: maternity and parental leave in Europe

Comparative social policy analysis has been shaped by the measurement of policy as a macro phenomenon. However, social policy theories have consistently asserted that policy entitlements vary across class, gender, ethnicity and the life-course. This paper synthesises a number of innovations to produce an approach which allows researchers to explore the policy heterogeneity within populations, across populations and over time. Using the example of maternity and parental leave, policy entitlements are identified through the calculation of financial support an individual would receive if they were to have a child, using a combination of legislative rules with representative survey sample. The results reveal far greater heterogeneity in policy entitlements than existing indicators suggest, with considerable implications for research on maternity and parental leave. This approach is not limited to maternity and parental leave benefits and demonstrates a way to explore comparative social policy in greater depth and detail.     

Juggling three life spheres: reconciling work,family and politics

In the field of work–life balance, most research focuses on the reconciliation of role-related expectations that derive from the work and family spheres. This article aims to identify coping strategies that reconcile life spheres in situations that go beyond the classic two-sphere framework. We analyze the actual coping behavior of individuals juggling three life spheres by studying local Flemish politicians. The strategies that were found in this study were communication with family, recognizing priorities within the political sphere, consciously creating time for family moments, downsizing and segregating the life spheres. The results suggest that women usually remain the manager of the household, which reinforces traditional gender roles.