Showing papers by "Concordia University published in 1998"

Nonsmooth analysis and control theory

Abstract: Proximal Calculus in Hilbert Space.- Generalized Gradients in Banach Space.- Special Topics.- A Short Course in Control Theory.

Photoassisted Degradation of Dye Pollutants. V. Self-Photosensitized Oxidative Transformation of Rhodamine B under Visible Light Irradiation in Aqueous TiO2 Dispersions

Abstract: Chemical oxygen demand (CODCr) and proton NMR, UV−vis, and spin trapping EPR spectroscopic evidence is presented to demonstrate the inverse photosensitized oxidative transformation of tetraethylated rhodamine (RhB) under visible illumination of aqueous titania dispersions. Both de-ethylation and oxidative degradation take place with the former proceeding in a stepwise manner to yield mono-, di-, tri-, and tetra-de-ethylated rhodamine species. Intermediates present after each de-ethylation step remain in a fast dynamic equilibrium between the titania particle surface and the bulk solution. The concentration of •OH radicals, formed from the inverse photosensitization process through the superoxide radical anion, increases upon addition of the anionic dodecylbenzene sulfonate surfactant (DBS) because a larger number of RhB excited states are able to inject an electron into the conduction band of the TiO2 particles. Also, intermediates that can no longer absorb the visible light, (i.e., once the dye solution ...

Exploratory mining and pruning optimizations of constrained associations rules

Abstract: From the standpoint of supporting human-centered discovery of knowledge, the present-day model of mining association rules suffers from the following serious shortcomings: (i) lack of user exploration and control, (ii) lack of focus, and (iii) rigid notion of relationships. In effect, this model functions as a black-box, admitting little user interaction in between. We propose, in this paper, an architecture that opens up the black-box, and supports constraint-based, human-centered exploratory mining of associations. The foundation of this architecture is a rich set of constraint constructs, including domain, class, and SQL-style aggregate constraints, which enable users to clearly specify what associations are to be mined. We propose constrained association queries as a means of specifying the constraints to be satisfied by the antecedent and consequent of a mined association.In this paper, we mainly focus on the technical challenges in guaranteeing a level of performance that is commensurate with the selectivities of the constraints in an association query. To this end, we introduce and analyze two properties of constraints that are critical to pruning: anti-monotonicity and succinctness. We then develop characterizations of various constraints into four categories, according to these properties. Finally, we describe a mining algorithm called CAP, which achieves a maximized degree of pruning for all categories of constraints. Experimental results indicate that CAP can run much faster, in some cases as much as 80 times, than several basic algorithms. This demonstrates how important the succinctness and anti-monotonicity properties are, in delivering the performance guarantee.

Preadolescent friendship and peer rejection as predictors of adult adjustment.

Abstract: Although peer-rejected children appear to be at risk for later difficulties, the contribution of preadolescent friendship to adaptive adjustment lacks an empirical foundation. In this 12 year follow-up investigation, 30 young adults who had a stable, reciprocal best friend in fifth grade and 30 who had been chumless completed measures of adjustment in multiple domains. Friendship and peer rejection were found to have unique implications for adaptive development. Lower levels of preadolescent peer rejection uniquely predicted overall life status adjustment, whereas friended preadolescents had higher levels of general self-worth in adulthood even after controlling for perceived competence in preadolescence. In contrast, peer rejection and the absence of friendship were both associated with psychopathological symptoms in adulthood, although neither was uniquely predictive of symptomatology.

Photoassisted Degradation of Dye Pollutants. 3. Degradation of the Cationic Dye Rhodamine B in Aqueous Anionic Surfactant/TiO2 Dispersions under Visible Light Irradiation: Evidence for the Need of Substrate Adsorption on TiO2 Particles

Abstract: The TiO2 photoassisted degradation of the cationic dye rhodamine B (RhB) has been examined in aqueous dispersions under visible light irradiation at wavelengths longer than 470 nm in the presence and absence of the anionic surfactant sodium dodecylbenzenesulfonate (DBS). RhB degrades slowly via a pH-independent process in TiO2 dispersions containing no DBS. The surfactant DBS adsorbs strongly on the TiO2 particles and significantly accelerates RhB degradation with initial rates reaching maximal values at the critical micelle concentration of DBS (cmc = 1.2 mM). In the presence of DBS, rates decrease with increase in pH, an effect directly attributable to variations in the extent of adsorption of RhB with changes in the surface charge of TiO2 particles. The zeta (ζ)-potentials of TiO2 particles in RhB/DBS/TiO2 dispersions (pH 2.1) show that DBS significantly enhances RhB adsorption and correlates with an enhancement in the rate of photodegradation of RhB. The results confirm the heretofore presumed but val...

TiO2-assisted photodegradation of dye pollutants : II. Adsorption and degradation kinetics of eosin in TiO2 dispersions under visible light irradiation

Abstract: The TiO2-assisted photodegradation of anionic eosin has been examined in TiO2 aqueous dispersions under illumination by visible light. Eosin is easily decomposed photochemically by visible light in the presence of TiO2 particles. The degradation kinetics followed a Langmuir-Hinshelwood type equation. The rate was greater in acid media than in neutral and alkaline media, which correlates with the adsorption behavior of eosin on the TiO2 surface. Adsorption of eosin is a prerequisite for the TiO2-assisted photodegradation. The evolution of CO2 occurred concomitantly with the photodegradation of eosin. A plausible mechanism of degradation is discussed.

The Role of Corticotropin-Releasing Factor and Corticosterone in Stress- and Cocaine-Induced Relapse to Cocaine Seeking in Rats

Abstract: We have shown previously that footshock stress and priming injections of cocaine reinstate cocaine seeking in rats after prolonged drug-free periods (Erb et al., 1996). Here we examined the role of brain corticotropin-releasing factor (CRF) and the adrenal hormone corticosterone in stress- and cocaine-induced reinstatement of cocaine seeking in rats. The ability of footshock stress and priming injections of cocaine to induce relapse to cocaine seeking was studied after intracerebroventricular infusions of the CRF receptor antagonist D-Phe CRF12-41, after adrenalectomy, and after adrenalectomy with corticosterone replacement. Rats were allowed to self-administer cocaine (1.0 mg/kg/infusion, i.v) for 3 hr daily for 10-14 d and were then placed on an extinction schedule during which saline was substituted for cocaine. Tests for reinstatement were given after intermittent footshock (10 min; 0.5 mA) and after priming injections of saline and cocaine (20 mg/kg, i.p.). Footshock reinstated cocaine seeking in both intact animals and animals with corticosterone replacement but not in adrenalectomized animals. The CRF receptor antagonist D-Phe CRF12-41 blocked footshock-induced reinstatement at all doses tested in both intact animals and animals with corticosterone replacement. Reinstatement by priming injections of cocaine was only minimally attenuated by adrenalectomy and by pretreatment with D-Phe CRF12-41. These data suggest that brain CRF plays a critical role in stress-induced, but only a modulatory role in cocaine-induced, reinstatement of cocaine seeking. Furthermore, the data show that although reinstatement of cocaine seeking by footshock stress requires minimal, basal, levels of corticosterone, stress-induced increases in corticosterone do not play a role in this effect.

A recursive thresholding technique for image segmentation

Abstract: In this correspondence, we present a general recursive approach for image segmentation by extending Otsu's (1978) method. The new approach has been implemented in the scope of document images, specifically real-life bank checks. This approach segments the brightest homogeneous object from a given image at each recursion, leaving only the darkest homogeneous object after the last recursion. The major steps of the new technique and the experimental results that illustrate the importance and the usefulness of the new approach for the specified class of document images of bank checks is presented.

CP-154,526, a selective, non-peptide antagonist of the corticotropin-releasing factor1 receptor attenuates stress-induced relapse to drug seeking in cocaine- and heroin-trained rats.

Abstract: We have found that peptide antagonists of corticotropin-releasing factor (CRF) receptors attenuate reinstatement of heroin and cocaine seeking induced by footshock. Here we examined the effect of a non-peptide, selective CRF1 receptor antagonist, CP-154,526, on reinstatement of heroin and cocaine seeking induced by footshock. Rats were trained to self-administer heroin or cocaine (0.1 and 1.0 mg/kg per infusion, IV, respectively) for 9–12 days. Extinction sessions were given for up to 14 days, during which saline was substituted for the drugs. Tests for reinstatement were then conducted after exposure to intermittent footshock (10 or 15 min, 0.5 mA). The footshock stressor reliably reinstated extinguished cocaine- and heroin-taking behavior. Pretreatment with CP-154,526 (15 and 30 mg/kg, SC) significantly attenuated the reinstatement effect of the stressor in both heroin- and cocaine-trained rats. CP-154,526, administered in the absence of the footshock stressor, did not affect extinguished drug seeking. In addition, in a separate experiment, CP-154,526 was shown not to alter high rates of lever pressing for a 10% sucrose solution, suggesting that the suppression of lever pressing in stress-induced reinstatement is not caused by a performance deficit. These results extend previous reports on the role of CRF in reinstatement of drug seeking induced by stressors. The present data also suggest that, to the extent that exposure to environmental stressors provoke relapse to drug use in humans, systemically effective CRF receptor antagonists may be of use in the treatment of relapse to drug use.

Plant O-methyltransferases: molecular analysis, common signature and classification

Abstract: Comparative analysis of the predicted amino acid sequences of a number of plant O-methyltransferase cDNA clones show that they share some 32–71% sequence identity, and can be grouped according to the different compounds they utilise as substrates. Five highly conserved regions are proposed as a signature for plant O-methyltransferases, two of which (regions I and IV) are believed to be involved in S-adenosyl-L-methionine and metal binding, respectively. The glycine-rich signature regions include a 36 amino acid domain which is located in the mid-terminal section of the carboxy terminus of most O-methyltransferase sequences. Cladistic analysis of the amino acid sequences suggests that plant O-methyltransferases may have arisen from common ancestral genes that were driven by different structural and/or functional requirements, and whose descendants segregated into different biochemical species. A comprehensive classification of plant O-methyltransferases is proposed following the guidelines of the Commission of Plant Gene Nomenclature.

The consensus glossary of temporal database concepts — February 1998 version

Abstract: This document1 contains definitions of a wide range of concepts specific to and widely used within temporal databases. In addition to providing definitions, the document also includes explanations of concepts as well as discussions of the adopted names.

Validation of the Indicators of Abuse (IOA) Screen

Abstract: It is important to enable social service agency practitioners to identify cases in which seniors are abused by their caregivers. The Indicators of Abuse (IOA) screening measure provides an abuse screening tool, based on abuse indicators, for use by practitioners. The study (N = 341) supports the validity of the 29-item set of indicators of the IOA, which discriminates abuse cases (84.4% of the time) from nonabuse cases (99.2% of the time). An abuse-indicator model evolving from the IOA suggests three main types of abuse signals: (a) caregiver personal problems/issues; (b) caregiver interpersonal problems/ issues; (c) care receiver social support shortages and past abuse.

Intergenerational transfer of psychosocial risk in women with childhood histories of aggression, withdrawal, or aggression and withdrawal.

Abstract: Intergenerational transfer of risk between mothers and children, based on mothers' childhood aggression and social withdrawal, was examined in an inner-city sample. Each of the 3 studies reported involved a subset of the 909 female participants in the Concordia Longitudinal Risk Project, initiated when the participants were of school age. Using medical records, Study 1 (n = 853) focused on prediction of teen motherhood, delivery complications during childbirth, multiparity, and close spacing of births. Study 2 (n = 428) examined pathways to school dropout and teen parenthood. Study 3 (n = 89) involved prediction of observed parent and child behavior from mothers' childhood characteristics. Mothers' childhood aggression was consistently predictive of negative outcomes in each area of intergenerational risk, especially when combined with social withdrawal and low levels of academic achievement. Education was protective: Mothers' years of schooling predicted positive outcomes.

Translation-invariant denoising using multiwavelets

Abstract: Translation invariant (TI) single wavelet denoising was developed by Coifman and Donoho (1994), and they show that TI is better than non-TI single wavelet denoising. On the other other hand, Strela et al. (1994) have found that non-TI multiwavelet denoising gives better results than non-TI single wavelets. We extend Coifman and Donoho's TI single wavelet denoising scheme to multiwavelets. Experimental results show that TI multiwavelet denoising is better than the single case for soft thresholding.

Strategic organizational change: the role of leadership, learning, motivation and productivity

Abstract: Presents an overview of strategic organizational change (SOC) and its managerial impact on leadership, learning, motivation and productivity. Theoretical and empirical data presented are: the sources and determinants of strategic organizational change; the management implications of SOC; organizational leadership within the context of SOC; learning aspects of SOC; the impact of SOC on organizational and individual productivity; a model that explains the relationships between SOC, leadership, learning, motivation and productivity. Depicts strategic organizational change as an integrative process with all organizational elements such as human resources, systems and technologies being considered for successful change to occur. The proposed model for strategic organizational change is an attempt to link the software and hardware components of organizations. In view of the pressures being expected from the external environment and the critical vision of organizations, research suggests that top management needs to establish a flexible and adaptive infrastructure that should lead contemporary and complex organizations to optimum levels of performance. The largest barrier to “change” is not changes to technologies and work processes but changes involving people.

Assessing the development of automaticity in second language word recognition.

Abstract: This study investigated the development of automaticity in second language word recognition. In an earlier study (Segalowitz & Segalowitz, 1993) we demonstrated that a reduction in the coefficient of variation of lexical decision reaction time (CV RT ) - the standard deviation of reaction time divided by mean reaction time (RT) - reflects a restructuring of underlying cognitive processing mechanisms in the direction of increased automaticity and not a simple speed-up of those mechanisms. In the current study, English speakers studying French performed multiple lexical decision tasks. Differences in CV RT were compared cross-sectionally and longitudinally. As in the earlier study, crosssectional analyses showed that CV RT correlated positively with RT for initially fast, but not initially slow, responders. CV RT also correlated positively with RT in longitudinal analyses. These results confirm that, with extended learning experience, the cognitive components underlying word recognition are restructured (automatized) and not simply speeded-up.

Electrical Stimulation of the Prefrontal Cortex Increases Cholecystokinin, Glutamate, and Dopamine Release in the Nucleus Accumbens: an In Vivo Microdialysis Study in Freely Moving Rats

Abstract: In vivo microdialysis, radioimmunoassay, and HPLC with electrochemical or fluorometric detection were used to investigate the release of cholecystokinin (CCK), glutamate (Glu), and dopamine (DA) in nucleus accumbens septi (NAS) as a function of ipsilateral electrical stimulation of medial prefrontal cortex (mPFC). CCK was progressively elevated by mPFC stimulation at 50-200 Hz. Stimulation-induced CCK release was intensity-dependent at 250-700 microA. NAS Glu and DA levels were each elevated by stimulation at 25-400 Hz; the dopamine metabolites DOPAC and homovanillic acid were increased by stimulation at 100-400 Hz. When rats were trained to lever press for mPFC stimulation, the stimulation induced similar elevations of each of the three transmitters to those seen with experimenter-administered stimulation. Perfusion of 1 mM kynurenic acid (Kyn) into either the ventral tegmental area (VTA) or NAS blocked lever pressing for mPFC stimulation. VTA, but not NAS, perfusion of Kyn significantly attenuated the increases in NAS DA levels induced by mPFC stimulation. Kyn did not affect NAS CCK or Glu levels when perfused into either the VTA or NAS. The present results are consistent with histochemical evidence and provide the first in vivo evidence for the existence of a releasable pool of CCK in the NAS originating from the mPFC. Although dopamine is the transmitter most closely linked to reward function, it was CCK that showed frequency-dependent differences in release corresponding most closely to rewarding efficacy of the stimulation. Although not essential for the reward signal itself, coreleased CCK may modulate the impact of the glutamatergic action in this behavior.

Italian ethnic identity and its relative impact on the consumption of convenience and traditional foods

Abstract: Ethnic identity or the retention or loss of the attitudes, values and behaviours of one’s culture of origin is presented as a multidimensional construct. It is further suggested that acculturation or the acquisition of traits of the dominant/host culture constitutes a separate yet correlated process. Initial exploratory and confirmatory factor analyses were conducted on responses from Italian‐Canadians to various items designed to tap Italian ethnic identity. These analyses revealed that ethnic identity did indeed constitute a multidimensional process. Specifically, three dimensions were identified: Italian Social Interaction and Participation, Italian Language Use with Family Members, and Catholicism. A final CFA model incorporated the three ethnic identity dimensions and two dimensions of acculturation. Consistent with previous findings, LISREL VIII estimation resulted in significant negative correlations between some ethnic identity and acculturation dimensions. The discriminant validity of ethnic identity was also more thoroughly established vis‐a‐vis acculturation by computing 95 per cent confidence intervals for the parameter estimates. Finally, subsequent stepwise regression analyses showed that the three ethnic identity dimensions along with the two acculturation dimensions and three socioeconomic factors had differential impacts on the consumption of various convenience and traditional foods. A hypothesis holding that ethnic identity was negatively related to the consumption of convenience foods was partly confirmed. Another holding that it was positively related to the consumption of traditional Italian foods was better established.

The effect of dominance hierarchy on the use of alternative foraging tactics: a phenotype-limited producing-scrounging game

Abstract: Group living is thought to be advantageous for animals, though it also creates opportunities for exploitation. Using food discovered by others can be described as a producer-scrounger, frequency-dependent game. In the game, scroungers (parasitic individuals) do better than producers (food finders) when scroungers are rare in the group, but they do worse when scroungers are common. When the individuals' payoffs do not depend on their phenotype (i.e. a symmetric game), this strong negative frequency dependence leads to a mixed stable solution where both alternatives obtain equal payoffs. Here, we address the question of how differences in social status in a dominance hierarchy influence the individuals' decision to play producer or scrounger in small foraging groups. We model explicitly the food intake rate of each individual in a dominance-structured foraging group, then calculate the Nash equilibrium for them. Our model predicts that only strong differences in competitive ability will influence the use of producing or scrounging tactics in small foraging groups; dominants will mainly play scrounger and subordinates will mostly use producer. Since the differences in competitive ability of different-ranking individuals likely depend on the economic defendability of food, our model provides a step towards the integration of social foraging and resource defence theories.

A Management Capacity Constraint? Obstacles to the Development of the Overseas Chinese Family Business

Abstract: Overseas Chinese family business (OCFBs) have gained a reputation for cost efficiency, responsiveness, and flexibility as original equipment manufacturers (OEMs) and as pioneers of the mainland's industrialization. This success is based upon a relatively simple ‘personally managed’ organization operating within a network of kin and ethnic relations. To what extent are mid-sized OCFBs now able to develop the capacity to compete in new strategic domains and manage more complex value chains? The paper examines competing views of the OCFBs organizational and competitive capabilities. The strategies of 50 mid-sized Hong Kong based manufacturing firms are used to provide insight into the questions of capabilities upgrading and long-term competitiveness in personally managed enterprises. In contrast to prevailing cultural and institutional accounts of OCFB behavior, the paper suggests that current (western) theory of the family firm and of organizational networks provides an alternative explanation of observed investment strategies and organizational structure.

Response categories and potential cultural bias: effects of an explicit middle point in cross‐cultural surveys

Abstract: The present study investigated whether questionnaires using explicit midpoints produce different results for different cultural groups. We hypothesized that managers from China, Japan, and Hong Kong (CJH) respond differently to Western management scales than do managers from the US., Germany, and United Kingdom (UGU). We found differences in central tendency (the likelihood of choosing the midpoint in overall variance between these groups). Using scales with even numbered response categories (thus removing the explicit midpoint) decreases the central tendencies of the CJH group and increases the variance in the responses to Western management questionnaire. Results suggested that when survey questionnaires are used in CJH cultures, careful consideration should be given to the choice between scales with even‐numbered response categories and those with odd‐numbered response categories.

Effects of Pedunculopontine Tegmental Nucleus Lesions on Responding for Intravenous Heroin under Different Schedules of Reinforcement

Abstract: The pedunculopontine tegmental nucleus (PPTg) is believed to play important roles in reward and learning. We examined the effect of PPTg lesions (0.5 μl of 0.1 m NMDA injected bilaterally over 10 min) on the learning of an operant response for opiate reward. In 14 adult male Long–Evans rats, bilateral lesions of the PPTg disrupted the acquisition of responding for intravenous heroin (0.1 mg/kg infused at a rate of 0.25 ml/28 sec) on a fixed ratio-1 (FR-1) schedule of reinforcement. The 12 remaining lesioned animals increased their heroin intake over the acquisition sessions but did not reach the response levels of sham-lesioned animals on the 15th and final session. The sham- and PPTg-lesioned animals that learned the FR-1 task exhibited similar patterns of responding during extinction and reacquisition sessions. When tested on a progressive ratio (PR) schedule of reinforcement, however, PPTg-lesioned animals had lower break points than sham-lesioned animals. Asymmetric lesions, which destroyed the majority of the nucleus in one hemisphere only, did not produce any behavioral deficits. Rats that were lesioned after training also did not show deficits in responding under either FR or PR schedules. These findings suggest that PPTg lesions reduce the rewarding effect of opiates but do not disrupt the ability either to learn an operant response or the response requirements of a PR schedule.

Dopamine Receptor Antagonists in the Nucleus Accumbens Attenuate Analgesia Induced by Ventral Tegmental Area Substance P or Morphine and by Nucleus Accumbens Amphetamine

Abstract: In the present study, we examined the effects of dopamine (DA) receptor antagonists infused into the nucleus accumbens septi (NAS) on analgesia induced by intra-ventral tegmental area (VTA) infusions of the substance P (SP) analog, DiMe-C7 or morphine and intra-NAS infusions of amphetamine. Rats received intra-NAS infusions of either the mixed DA receptor antagonist flupenthixol (1.5 or 3.0 microg/0.5 microl/side; DiMe-C7 only), the DA D1/D5 receptor antagonist SCH 23390 (0.1 microg/0.5 microl/side; DiMe-C7 only) or the DA D2-type receptor antagonist raclopride (1.0, 3.0 or 5.0 microg/0.5 microl/side). Ten minutes later, rats received intra-VTA infusions of DiMe-C7 (3.0 microg/0.5 microl/side) or morphine (3.0 microg/0.5 microl/side) or intra-NAS infusions of amphetamine (2.5 microg/0.5 microl/side). Animals were then administered the formalin test for tonic pain. Intra-NAS raclopride prevented analgesia induced by intra-VTA DiMe-C7, intra-VTA morphine and intra-NAS amphetamine. Similarly, intra-NAS flupenthixol or SCH 23390 attenuated the analgesia induced by intra-VTA DiMe-C7. These findings suggest that tonic pain is inhibited, at least in part, by enhanced DA released from terminals of mesolimbic neurons. Furthermore, the evidence that SP and opioids in the VTA mediate stress-induced analgesia suggests that the pain-suppression system involving the activation of mesolimbic DA neurons is naturally triggered by exposure to stress, pain or both.

State variable decoupling and power flow control in PWM current-source rectifiers

Abstract: Pulsewidth modulated (PWM) current-source rectifiers (CSR), among other alternatives, offer marked improvements over thyristor line-commutated rectifiers as a source of variable DC power. Advantages include reduced line current harmonic distortion and complete displacement power factor control, including unity displacement power factor operation. However, due to nonlinearities of the PWM-CSR model, their control has usually been carried out using direct line current control in a three-phase stationary frame (abc). This paper proposes the application of a nonlinear control technique that introduces more flexibility in the control of the rectifier and results in a more straightforward approach to controller design. The proposed technique is based on a nonlinear state variable feedback approach in the rotating frame (dq). The approach allows the independent control of the two components of the line current (active and reactive) with the same dynamic performance, regardless of the operating point. The control strategy also eliminates the need for input damping resistors and rejects the effect of supply voltage variations. Furthermore, a space vector modulation (SVM) technique is used to maximize the supply voltage utilization. This paper includes a complete formulation of the system equations and a controller design procedure. Experimental results on a 2 kVA digital-signal-processor-controlled prototype confirm the validity of theoretical considerations.

Resource-driven scheduling of repetitive activities

Abstract: Repetitive activities are found commonly in the construction of high-rise buildings, pipeline networks and highway and housing projects. Construction crews assigned to these activities often perform the work sequentially, moving from one repetitive unit in the project to the next. Because of this frequent crew movement, construction of repetitive activities should be scheduled in such a way as to enable prompt movement of crews among the repetitive units so as to minimize idle crew time. In order to maximize the efficiency of crew utilization, the schedule of repetitive activities should be resource driven, and should satisfy the crew work continuity constraint in addition to precedence relationships and crew availability constraints. This paper presents a flexible algorithm for resource-driven scheduling of repetitive activities that satisfies the three constraints, and considers the impact of a number of practical factors encountered commonly during the construction of this class of projects. The algori...

Children's Salivary Cortisol, Internalising Behaviour Problems, and Family Environment: Results from the Concordia Longitudinal Risk Project

Abstract: To explore the possibility that children’s adrenocortical reactions to parent-child conflict influence their vulnerability for internalising behaviour problems, we studied 62 mother-child dyads from the Concordia Longitudinal Risk Project. Standardised measures of maternal, child, and family adjustment were collected. Mother’s and children’s saliva was sampled before and after a conflict-oriented mother-child interaction task and was later assayed for cortisol. The children’s pre-task cortisol scores were negatively associated with their internalising behaviour problems, their mother’s childhood levels of socially withdrawn behaviour and current psychosocial problems, as well as dimensions of family environment representing the open expression of aggression, anger, and conflict. Children’s cortisol levels after the interaction task were lowest for those raised by mothers with high childhood levels of aggressive behaviour problems, and in family environments characterised by rigid rules. Interrelationships...