Recognizing Structural Nonidentifiability: When Experiments Do Not Provide Information About Important Parameters and Misleading Models Can Still Have Great Fit

In the quest to model various phenomena, the foundational importance of parameter identifiability to sound statistical modeling may be less well appreciated than goodness of fit. Identifiability concerns the quality of objective information in data to facilitate estimation of a parameter, while nonidentifiability means there are parameters in a model about which the data provide little or no information. In purely empirical models where parsimonious good fit is the chief concern, nonidentifiability (or parameter redundancy) implies overparameterization of the model. In contrast, nonidentifiability implies underinformativeness of available data in mechanistically derived models where parameters are interpreted as having strong practical meaning. This study explores illustrative examples of structural nonidentifiability and its implications using mechanistically derived models (for repeated presence/absence analyses and dose–response of Escherichia coli O157:H7 and norovirus) drawn from quantitative microbial risk assessment. Following algebraic proof of nonidentifiability in these examples, profile likelihood analysis and Bayesian Markov Chain Monte Carlo with uniform priors are illustrated as tools to help detect model parameters that are not strongly identifiable. It is shown that identifiability should be considered during experimental design and ethics approval to ensure generated data can yield strong objective information about all mechanistic parameters of interest. When Bayesian methods are applied to a nonidentifiable model, the subjective prior effectively fabricates information about any parameters about which the data carry no objective information. Finally, structural nonidentifiability can lead to spurious models that fit data well but can yield severely flawed inferences and predictions when they are interpreted or used inappropriately.     

Training Intraverbal Naming to Establish Matching-to-Sample Performances

The current study evaluated whether training intraverbal naming would be sufficient to establish visual-visual matching-to-sample (MTS) performances in college students. In the first experiment, we used a multiple-probe design across stimulus sets to assess whether six participants could match arbitrary visual stimuli (AB) after learning to tact their two experimentally defined classes (A’ and B’) and then intraverbally relate their names (i.e., “A’ goes with B’”). All participants matched the stimuli accurately after training, as well as emitted the trained intraverbals. In the second experiment, we used a multiple baseline design across four participants to assess whether the same training would produce bi-directional intraverbals in the form of “B’ goes with A’,” and MTS performance consistent with symmetry (BA). All participants responded accurately during matching and intraverbal tests. Across both experiments, participants stated the trained intraverbals while performing the matching task. Results showed that MTS performance can be established solely by verbal behavior training.     

Does state ownership really matter? The dynamic alignment of China's resource environment and firm internationalization strategies

Recent research suggests that unequal access to home country institutional resources affects firm internationalization strategies. We add to this debate, based on an analysis of state-owned (SOEs) and non-state-owned (NSOEs) Chinese mining firms, by developing a more dynamic and multi-layered understanding of this interplay. We find that home institutional support can be ownership-based or performance-based, whereby the former benefits SOEs and the latter favors high-performing NSOEs. Combined, these support structures serve as institutional control mechanisms in promoting competition, performance and loyalty to national policies. In addition, they establish a permanent link between firm- and home country-specific assets and incentivize firms to develop dynamic resource access capabilities at home and abroad. Our findings inform our understanding of the firms-institutions nexus and Chinese foreign direct investment dynamics, especially in industries of strategic importance to the state.     

Social Exclusion, Inequality and Social Work

This paper sets out the environment of inequality in which social work and the poor have recently operated. It explores pragmatic and idealist arguments concerning whether or not the poor need social work. Finally, policy solutions developed in consultation with social service users and carers are suggested in relation to poverty and social exclusion. Social exclusion can be linked to relative poverty as exclusion from economic and social norms. However, there is a wider brief in our own government’s publications and those of Europe, of examining how people are excluded from actions and policies of agencies who are there to support them. This paper will retain the concepts of poverty as lack of material income, and inequality as the gap between the rich and the poor, while being aware of the policy implications for social service users and carers of the more comprehensive process of being shut out partially or fully from social, economic, political and cultural systems. The debates around social work, social exclusion and inequality that follow establish: that some of the poor do need social work; that the poverty of social service users is related to policies that have restructured welfare in Britain; that the reason for individuals approaching or being referred to social services are complex but are likely to include financial deprivation as a key contributory factor; that if the poor do need social work, advocacy is essential rather than social work being seen as concerned only with social control—taking children into care, mentally ill people into hospitals, and advising the DSS on the suitability of claimants for benefits. Finally, the discussion turns to new policy agendas on social exclusion instigated by the Labour government. What positive difference can such policies make for social service users, their carers and social workers?.     

Alternative ideologies of la francophonie

This paper concerns current transformations in the relationship between political and linguistic ideologies of la francophonie based on a sociolinguistic ethnographic study in a French-language minority school in Canada. A dominant modernist orientation, focussing on unilingual social spaces and the authenticity and integrity of French, is being confronted by an emerging globalizing orientation which emphasizes the value of French as an economic resource, or commodity, and which values both pluralism and a common language. The result is a crisis of legitimacy for francophone institutions, struggles for voice among old and new elites, and the marginalization of the working class speakers of the ‘authentic’ vernacular.     

Socioeconomic Status,Family Processes,and Individual Development

Research during the past decade shows that social class or socioeconomic status (SES) is related to satisfaction and stability in romantic unions, the quality of parent‐child relationships, and a range of developmental outcomes for adults and children. This review focuses on evidence regarding potential mechanisms proposed to account for these associations. Research findings reported during the past decade demonstrate support for an interactionist model of the relationship between SES and family life, which incorporates assumptions from both the social causation and social selection perspectives. This review concludes with recommendations for future research on SES, family processes, and individual development in terms of important theoretical and methodological issues yet to be addressed.     

Rural tourism and livelihood strategies in Romania

Substantial changes in the Romanian countryside accompanied by the need for more robust economic activities have caused some families to turn to tourism as an economic diversification strategy. A qualitative study of selected rural tourism entrepreneurs indicates positive experiences, both economically and in other aspects of their lives. However, the development of rural tourism is highly uneven spatially and the Romanian Government should act more incisively to support families establishing guesthouses.     

Affairs of the Heart: Qualities of Adolescent Romantic Relationships and Sexual Behavior

We know more about parent and peer influences than about the ways in which specific qualities of adolescent romantic relationships may influence sexual decision‐making. Using data from the Toledo Adolescent Relationships Study, we focus on communication processes and emotional feelings, as well as more basic contours of adolescent romantic relationships, including power and influence dynamics. Controlling for traditional predictors and duration of the relationship, results suggest that subjectively experienced relationship qualities matter for understanding teens' sexual behavior choices. Further, findings indicate a similar effect of most relationship qualities on male and female reports of sexual behavior. However, influence and power dynamics within the relationship were not related to the likelihood that boys reported sexual intercourse in a focal relationship. In contrast, girls who perceived a more favorable power balance were less likely to report sexual intercourse than their female counterparts who perceived a less favorable power balance. Recognizing that the results capture reciprocal influence processes, longitudinal and qualitative data are used to further explore the complex nature of these associations.     

Suicide Prevention Training Program for Gatekeepers Working in Community Hospice Settings

Gatekeepers in community hospice settings encounter patients and caregivers struggling with suicidal thoughts. Limited guidance is available for training staff on the prevention of suicide in hospice care. This study evaluated one promising, evidence-based, suicide prevention program with a behavioral rehearsal practice session. A pre- and post-, one group design, was utilized to measure the training impact and educational needs of staff working in community hospice settings (N =39). Training increased awareness of the risk factors for suicide, as reported by nearly 80% of participants. Self-efficacy scores showed a statistically significant Increase, t(df = 35), ?9.59, p= .00 (two-tailed), from pretraining (n=36, M=2.21, SD= .65) to posttraining (n=36, M=3.03, SD=.56). Satisfaction and the need for additional devoted time for suicide prevention training were highly rated. Suicide prevention training programs can enhance self-efficacy, knowledge, and skills for gatekeepers working in community hospice settings.