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Black men who have sex with men (MSM) experience disproportionate rates of HIV infection in the USA, despite being no more likely to engage in sexual risk behaviors than other MSM racial/ethnic groups. HIV pre-exposure prophylaxis (PrEP) has been shown to reduce risk of HIV acquisition; however, rates of PrEP use among Black MSM remain low. Clinical, psychosocial, and structural factors have been shown to impact PrEP use and adherence among Black MSM. Care coordination of HIV prevention services has the potential to improve PrEP use and adherence for Black MSM, as it has been shown to improve HIV-related care outcomes among people living with HIV.Client-centered care coordination (C4) is a multi-level intervention designed to address clinical, psychosocial, and structural barriers to HIV prevention services for Black MSM within HPTN 073, a PrEP demonstration project among Black MSM in three cities in the USA. The current study examined the implementation process of C4, specifically investigating the activities, cost, time, and outcomes associated with the C4 intervention.On average, participants engaged in five care coordination encounters. The vast majority of care coordination activities were conducted by counselors, averaging 30 min per encounter. The cost of care coordination was relatively low with a mean cost of $8.70 per client encounter.Although client-centered care coordination was initially implemented in well-resourced communities with robust HIV research and service infrastructure, our findings suggest that C4 can be successfully implemented in resource constrained communities.

Despite evidence that acute stress impairs attention in adults, there has been minimal research in children. Here, the effects of acute stress on Go/No-go performance were examined in young children (M age = 5.41 years). Given the critical role of the parent-child relationship to children's self-regulatory development, the extent to which parenting stress predicts children's cognitive vulnerability to acute stress and autonomic reactivity was also investigated. A between-groups design (n = 58 stress, n = 26 control) was used with oversampling of the stressor-exposed children to examine individual differences. The Parenting Stress Index and subscales were employed as a measure of parenting stress. Acute stress impaired children's sustained attention, but not inhibitory control. Higher parenting stress was associated with vulnerability to attentional impairment. Parenting distress was also positively associated with sympathetic reactivity to acute stress, but neither sympathetic nor parasympathetic reactivity was associated with attentional impairment. A conceptual model of pathways through which repetitive acute stress may contribute to self-regulatory difficulties is presented, including the potential buffering role of caregivers.

Resume Objectif Cette etude a pour but de realiser une traduction francaise du Suicide Intervention Inventory-2 (SIRI-2) de Neimeyer & Mc Innes. Le SIRI-2 evalue les competences relationnelles des intervenants face a une personne en crise suicidaire. Ainsi, cet outil permettra de mieux evaluer l’efficacite des formations professionnelles en intervention de crise suicidaire. Methode La methode utilisee s’inspire du modele de traduction transculturelle de Vallerand. Cent sept etudiants en psychologie, medecine et soins infirmiers ont ete recrutes pour participer par diffusion d’un questionnaire numerique. Leurs resultats ont ete compares a ceux de six experts francophones de la prevention du suicide (groupe de comparaison). Les resultats des etudiants ont egalement ete compares avec les resultats du groupe d’experts americains qui demeurent les scores de references publies lors de l’elaboration du SIRI-2. Resultats Apres comparaison des resultats des experts francais avec ceux des experts americains (Neimeyer & Mc Innes), les items presentant la moins bonne fidelite ont ete supprimes pour aboutir a la version courte du SIRI-2 en 15 questions (SIRI-2-VF). Les analyses statistiques SIRI-2-VF montrent une bonne validite (la difference experts vs. sujets naifs est significative : t = 31,5, p Conclusion Le SIRI-2-VF permettra d’enrichir l’eventail des instruments d’evaluation en langue francaise applicables au domaine de la suicidologie. Il s’agit du premier outil permettant d’evaluer l’acquisition de competences cliniques apres une formation sur la crise suicidaire, qui atteint le niveau 2a de la pyramide de Kirpatrick.

Adolescence is a time of heightened neural plasticity. Many brain networks show protracted development through this period, such as those underlying inhibitory control (IC), a neurocognitive skill implicated in risk-taking and therefore relevant to public health. Although IC appears to be trainable in adults and young children, whether and how IC may be malleable during adolescence is not fully understood. In this pilot RCT, we tested the effects of a school-based IC training paradigm (versus active control) on IC performance and neural function in adolescents (N = 19) aged 15 to 17 recruited from a low-income school district. We also examined the extent to which training effects transferred to a non-trained IC task and real-world risk behavior, as well as potential moderation effects by early adversity exposure. Training altered brain function related to attention during IC preparation and implementation, though it did not alter IC performance in the training group compared to the control group. There was limited evidence of training transfer. Results have implications for translational neuroscience research in adolescents.

Although prior research has characterized stress system reactivity (i.e. hypothalamic-pituitary-adrenal axis, HPAA; autonomic nervous system, ANS) in children, it has yet to examine the extent to which biological reactivity predicts concurrent goal-directed behavior. Here, we employed a stressor paradigm that allowed concurrent assessment of both stress system reactivity and performance on a speeded-response task to investigate the links between biological reactivity and cognitive function under stress. We further investigated gender as a moderator given previous research suggesting that the ANS may be particularly predictive of behavior in males due to gender differences in socialization. In a sociodemographically diverse sample of young children (N = 58, M age = 5.38 yrs; 44% male), individual differences in sociodemographic covariates (age, household income), HPAA (i.e. cortisol), and ANS (i.e. respiratory sinus arrhythmia, RSA, indexing the parasympathetic branch; pre-ejection period, PEP, indexing the sympathetic branch) function were assessed as predictors of cognitive performance under stress. We hypothesized that higher income, older age, and greater cortisol reactivity would be associated with better performance overall, and flexible ANS responsivity (i.e. RSA withdrawal, PEP shortening) would be predictive of performance for males. Overall, females performed better than males. Two-group SEM analyses suggest that, for males, greater RSA withdrawal to the stressor was associated with better performance, while for females, older age, higher income, and greater cortisol reactivity were associated with better performance. Results highlight the relevance of stress system reactivity to cognitive performance under stress. Future research is needed to further elucidate for whom and in what situations biological reactivity predicts goal-directed behavior.

The validation of laboratory paradigms that reliably induce a stress response [including hypothalamic-pituitary-adrenal (HPA) axis and autonomic nervous system (ANS) activation], is critical for understanding how children's stress-response systems support emotional and cognitive function. Early childhood research to date is markedly limited, given the difficulty in establishing paradigms that reliably induce a cortisol response. Furthermore, research to date has not included a control condition or examined concurrent ANS reactivity. We addressed these limitations by characterizing the extent to which a modified matching task stressor paradigm induces HPA and ANS activation, beyond a closely matched control condition. Modifications include an unfamiliar and unfriendly assessor to increase the stressful nature of the task. Results validate the matching task as a laboratory stressor, with significant differences in HPA and ANS responsivity between conditions. The Stressor group exhibited a cortisol increase post-stressor, while the Control group was stable over time. Children in both conditions exhibited reduced parasympathetic activity to the first-half of the task, but in the second-half, only children in the Stressor condition, who were experiencing exaggerated signals of failure, exhibited further parasympathetic decline. The Stressor condition induced higher sympathetic activity (versus Control) throughout the task, with exaggerated second-half differences. Within the Stressor condition, responsivity was convergent across systems, with greater cortisol reactivity correlated with the magnitude of parasympathetic withdrawal and sympathetic engagement. Future research employing the matching task will facilitate understanding the role of HPA and ANS function in development.

There is growing evidence that social support can buffer the physiological stress response, specifically cortisol reactivity. We use a developmental framework to review the importance of social buffering in early childhood, a period of heightened plasticity for programming of the hypothalamic-pituitary-adrenal (HPA) axis. The social environment, in which parents play the largest role in early life, is a critical agent in the developmental trajectory of the HPA axis. A prevailing model of social buffering primarily focuses on the role of social support in the context of acute stressors and cortisol response. This review expands this model to provide evidence of the mechanism of social buffering, or lack thereof, across periods of chronic stress by applying the social buffer model to children involved in the child welfare system. We also highlight current interventions that capitalize on the mechanism of social buffering to modify HPA axis functioning across childhood. Last, we synthesize our findings using the social buffering framework to inform future targeted interventions.

Early adverse experiences are well understood to affect development and well-being, placing individuals at risk for negative physical and mental health outcomes. A growing literature documents the effects of adversity on developing neurobiological systems. Fewer studies have examined stress neurobiology to understand how to mitigate the effects of early adversity. This review summarizes the research on three neurobiological systems relevant to interventions for populations experiencing high levels of early adversity: the hypothalamic-adrenal-pituitary axis, the prefrontal cortex regions involved in executive functioning, and the system involved in threat detection and response, particularly the amygdala. Also discussed is the emerging field of epigenetics and related interventions to mitigate early adversity. Further emphasized is the need for intervention research to integrate knowledge about the neurobiological effects of prenatal stressors (e.g., drug use, alcohol exposure) and early adversity. The review concludes with a discussion of the implications of this research topic for clinical psychology practice and public policy.

BACKGROUND: Infants with prenatal substance exposure are at increased risk for developmental problems, with self-regulatory challenges being some of the most pronounced. The current study aimed to investigate the extent to which prenatal substance exposure (alcohol, opioids) impacts infant self-regulation during a relational stressor and the association between self-regulation and infant affect. METHODS: Participants were 100 mother-child dyads recruited prenatally (Mean = 23.8 gestational weeks) and completed the Still Face Paradigm (SFP) when infants were 5 to 8 months of age (Mean = 6.9 months) as part of an ENRICH prospective birth cohort study. Based on prospective repeated assessment of maternal substance use in pregnancy, infants were grouped into: 1) Unexposed controls; 2) Alcohol-exposed; 3) Opioid-exposed due to maternal use of medications for opioid use disorder (MOUD) with or without other opioids; 4) MOUD and alcohol. Infant stress reactivity (negative affect) and self-regulation were assessed during the validated 5-episode SFP. Mixed effects linear models were used to analyze differences in the percent of self-regulation and percent of negative affect among the study groups across SFP episodes, as well as the group-by-self-regulation interaction with respect to infant negative affect. RESULTS: The MOUD+Alcohol group demonstrated significantly lower self-regulation at baseline compared to controls (p < 0.05). There was a significant group-by-self-regulation interaction (p = 0.028). Higher self-regulation was associated with lower negative affect across SFP episodes in the MOUD+Alcohol group (p = 0.025) but not other groups. CONCLUSION: Self-regulation skills are particularly important for emotional modulation in infants with prenatal polysubstance exposure, highlighting the development of these skills as a promising intervention target.

Prior research has identified the role of childhood maltreatment in externalizing problems and executive function (EF) deficits, but minimal work has been done to characterize the effects of co-occurring maltreatment types, defined as polyvictimization. Here, we sought to characterize the association between polyvictimization and externalizing problems in a sample of foster care children aged 3-4 years (N = 84) and examine how EF may mediate or moderate that relationship. A moderation model was supported in that only polyvictimized children with EF scores 1.62 or more standard deviations below the mean were at heightened risk for clinically severe externalizing problems, while no association between polyvictimization and externalizing problems were observed for children who scored at the mean or above on the EF measure. Findings highlight that EF may serve as a resilience factor indicating that individual differences in polyvictimized children's EF skills help to predict variability in externalizing problems. Future research on designing and optimizing intervention programs that target EF skills may mitigate the development of maladaptive outcomes for polyvictimized children.

Roos and colleagues' commentary on our recent meta-analysis examining acute stress effects on executive functions is an important delineation of the limits of meta-analyses with heterogeneous outcomes. In this response, we wish to both clarify the inferences we feel are appropriate given the analyses and address the methodological concerns they raise. Additionally, we present new analyses that answer questions raised in their commentary. We first discuss the classification of a broad array of tasks that depend upon the same construct (e.g., inhibition) and note that this allows for inferences regarding the process that underpins all of those tasks, but this does not entail that all tasks dependent upon that construct will evidence the same effect of stress. Second, we argue that requiring that a study present a significant effect of stress on cortisol for inclusion in analyses is too stringent for a number of reasons (e.g., some studies using validated stressor paradigms correctly do not assay cortisol for budgetary reasons) and we present analyses showing that even when studies that did not present a cortisol response were removed, the initially observed effects still held. Finally, we address concerns raised regarding analyses of time-dependent effects by presenting new analyses that help to allay those concerns. In sum, we applaud Roos and colleagues' exortation for greater methodological and conceptual rigor in studies of stress and executive function, and the additional analyses prompted by their questions help to clarify observed effects and further the field of stress and executive function research.

In this study, we utilized a novel fMRI paradigm to examine the behavioral and neural correlates of parenting self-evaluation in a sample of mothers with at least one child under the age of 4 (N = 37). Prior self-report, behavioral and observational research document the implications of parenting self-evaluations for parent well-being and caregiving behavior; however, relatively little is known about the neural circuitry underlying these self-referential processes and to what extent they are influenced by caregiving experience. Although neuroimaging paradigms indexing other aspects of parental function exist, this is the first to use functional neuroimaging to study parenting self-evaluation in a controlled laboratory setting. We found parenting self-evaluations elicited significantly greater activity across most cortical midline structures, including the medial prefrontal cortex compared to control evaluations; these findings converge with previous work on the neural underpinning of general trait self-evaluation. Notable differences by parity were observed in exploratory analyses: specifically, primiparous mothers endorsed a higher number of developmentally supportive traits, exhibited faster reaction times, and showed a greater difference in mPFC activity when making self-evaluations of developmentally supportive traits than of developmentally unsupportive traits, compared to multiparous mothers. Implications of these findings and study limitations are discussed.

Identifying environmental influences on inhibitory control (IC) may help promote positive behavioral and social adjustment. Although chronic stress is known to predict lower IC, the immediate effects of acute stress are unknown. The parasympathetic nervous system (PNS) may be a mechanism of the stress-IC link, given its psychophysiological regulatory role and connections to prefrontal brain regions critical to IC. We used a focused assessment of IC (the stop-signal task) to test whether an acute social stressor (the Trier Social Stress Test) affected participants’ pre- to post-IC performance (n = 58), compared to a control manipulation (n = 31). High frequency heart-rate variability was used as an index of PNS activity in response to the manipulation. Results indicated that stress impaired IC performance, blocking the practice effects observed in control participants. We also investigated the associations between PNS activity and IC; higher resting PNS activity predicted better pre-manipulation IC, and greater PNS stressor reactivity protected against the negative effects of stress on IC. Together, these results are the first to document the immediate effects of acute stress on IC and a phenotypic marker (PNS reactivity to stressors) of susceptibility to stress-induced IC impairment. This study suggests a new way to identify situations in which individuals are likely to exhibit IC vulnerability and related consequences such as impulsivity and risk taking behavior. Targeting PNS regulation may represent a novel target for IC-focused interventions.

SummaryObjectives: To determine the short- and long-term outcome for sport horses after arthroscopic treatment of osteochondrosis of the lateral trochlear ridge of the femur.Methods: A retrospective study was performed using the medical records of horses intended for use as English sport horses. Outcome was obtained through telephone questionnaire.Results: Thirty-seven horses, mainly Warmbloods, underwent arthroscopic surgery for treatment of lateral femoral trochlear ridge osteochondrosis. Short-term outcome revealed that 27 of 37 horses had no complications. Seven horses had postoperative lameness and effusion which eventually resolved in four horses. Long-term outcome was available for 29 horses, of which 19 were performing to full expectations. Five horses were athletic but at a lower level than expected, and five horses were unable to be used. The depth of the lesion was significantly associated with short-term complications of effusion and lameness. The depth and length of the lesion were not associated with the long-term outcome, but involvement of structures other than the lateral trochlear ridge (patella, medial trochlear ridge) was associated with a worse prognosis.Clinical significance: The prognosis for sport horses following stifle arthroscopy for lateral trochlear ridge is similar to that reported in other studies and lesions at other sites within the stifle joint.

Training health professionals about suicidal crisis is one major line of suicide prevention worldwide. France has one of the highest suicide rates in Europe, and although crisis intervention training has been set up since 2001, there presently is no training assessment tool in the French language for health professionals trained in suicide prevention. In the four levels of Kirpatrick's education pyramid, training that takes place in France today solely assesses level one status, that is to say relative to the level of satisfaction of participants (self-report). This study proposes a validated short French version of the Suicide Intervention Response Inventory-2 (SIRI-2) of NeimeyerMc Innes. The SIRI-2 questionnaire assesses the ability of first line intervention in dealing with suicidal individuals.The translation methodology was inspired from Vallerand's model of cross-cultural back translation. This method is regularly used for translating from the English language to a French version. In order to translate the English version, we used an extensive 7-step methodology implicating several bilingual translators, expert reviewers (psychologists and psychiatrists) and a scientific committee. Participants were 107 students from different French universities and study programs: psychology, medicine and nursing (17 were men; average age was 26.6). Fifteen of these participants answered the SIRI-2-VF on two occasions (separated by a 15-day interval) in order to estimate the temporal stability of the instrument. The scores of the students were compared to six French experts in suicide prevention and with the original expert group who worked on the development of SIRI-2 (n=7). We used Student t Test for construct validity, Cronbach's Alpha for internal consistency and Pearson's correlation coefficient for temporal stability.Following a fidelity comparison of the results of the French experts with those of the American experts, ten items presenting the least good fidelity were suppressed in order to obtain a short version of the SIRI-2 containing 15 questions (SIRI-2-VF). Statistical analyses of the short version (15 questions, SIRI-2-VF) showed good validity (difference between experts and subjects is significant: t=31.5, P0.001) and reliability (good internal consistency: α=0.850 for positive statements and α=0.830 for negative statements, and a temporal stability: r=0.827, bilateral test, P0.001).This tool should improve the range of specific instruments in French suicidology adapted for French culture of suicide intervention. It is the first tool in France that reaches level 2a of Kirkpatrick's pyramid to assess clinical skills after training in suicidology.

According to the World Health Organization, depression has become the leading cause of disability in the world, contributing significantly to the burden of health issues especially in the industrialized countries. This is a major public health problem, with potential impact on work climates, productivity at work and the continued existence of the organizations. Some recent studies have examined potential links between professional factors and common mental health disorders, but none have demonstrated a direct causal link.In the present study, we explored possible links between work-related stressors and common mental health disorders, with the objective of determining priority mental health prevention axes.The study used a life trajectory method. We compared professional stressors and difficulties present in other spheres of life in the last five years between two groups: a group of 29 participants with common mental health disorders during the last five years (depression, anxiety disorders, eating disorders, substance use disorders, pathological gambling), and a group of 29 participants who have not experienced a mental health disorder in the last five years. Data were collected from semi-structured interviews with the participants using a life course analysis method. Each participant was interviewed during two or three meetings of two to three hour duration. Questions regarding difficulties in different spheres of life and mental health were asked. More precisely, data were collected with regards to the presence or absence of mental health disorders in the last five years and the nature of mental health disorders and difficulties. Moreover, we collected data pertaining to the most important positive and negative events in different spheres of life that were present in the last five years, including family life, romantic relationships, social life, academic difficulties, losses and separations, episodes of personal difficulties, financial difficulties as well as protective factors. Regarding professional difficulties present in the last five years, data were collected on different kinds of adversities such as difficulties in finding a job, periods of unemployment, frequent job changes, difficult working conditions, discrimination, difficult working relationships with colleagues and with employers, moral harassment and family-work conflicts.Participants with common mental health disorders are more concerned about having general professional difficulties at work and about having difficult working relationships with employers. However, difficulties related to other spheres of life do not differentiate the two groups.It is possible that the work environment is linked to common mental health disorders. In particular, having general professional stressors at the work place and having difficult relationships with employers can impact the occurrence of common mental health disorders. Inversely, these stressors at work can be the consequence of a common mental health disorder. Complementary studies are of interest. Professional stressors can constitute an essential part in the occurrence of common mental health disorders. Thus, the workplace seems a priority environment for deploying effective mental health prevention strategies. Moreover, this can be a strategy for organizations to improve the work climate and to increase productivity.

The aim of this study was to evaluate the perceptions and opinions of Canadian pet owners about anaesthesia, pain and surgery in dogs and cats.Six Canadian veterinary hospitals participated. Each practice received 200 copies of a questionnaire that were distributed to pet owners. Questions regarding the use of analgesics, anaesthesia, surgery and onychectomy (cats) were included. Responses were transformed into ordinal scores and analysed with a Cochran-Mantel-Haenszel test.A total of 849 out of 1200 questionnaires were returned. Owners believed more frequently that analgesics are needed for surgical procedures than for the medical conditions. Owners rated as very important/important: "knowing what to expect during illness/injury/surgery" (99·3%), "being assured that all necessary analgesic drugs/techniques will be used" (98·6%), "being informed about procedures/risk" (98·5%), and having a board-certified anaesthesiologist (90·5%). Most owners agreed/partly agreed that pain impacts quality of life (94·2%), and affects their pet's behaviour (89·5%). Most respondents (69%) were women; they were significantly more concerned than men about anaesthesia, pain, cost and client-communication. Cat owners believed that analgesics were necessary for some procedures/conditions significantly more often than canine-only owners. Pet owners with previous surgery disagreed more frequently that "pain after surgery can be helpful" and that "pain in animals is easy to recognize" than those without previous surgery. Most owners think onychectomy should be banned in cats (56·4%).This study identified important areas of client communication regarding pain and its control in pets.

Adolescents with prenatal substance (drug and alcohol) exposure exhibit inhibitory control (IC) deficits and aberrations in associated neural function. Nearly all research to date examines exposure to individual substances, and a minimal amount is known about the effects of heterogeneous exposure-which is more representative of population exposure levels. Using functional magnetic resonance imaging (fMRI), we investigated IC (Go/NoGo) in heterogeneously exposed (n = 7) vs. control (n = 7) at-risk adolescents (ages 13-17). The fMRI results indicated multiple IC processing differences consistent with a more immature developmental profile for exposed adolescents (Exposed > Nonexposed: NoGo > Go: right ventrolateral prefrontal cortex, right cuneus, and left inferior parietal lobe; NoGo > false alarm: occipital lobe; Go > false alarm: right anterior prefrontal cortex). Simple effects suggest exposed adolescents exhibited exaggerated correct trial but decreased incorrect trial activation. Results provide initial evidence that prenatal exposure across substances creates similar patterns of atypical brain activation to IC success and failure.

Wastewater sewage sludge cake from textile manufacturing was evaluated by soil incubation experiments and a greenhouse experiment for use as a soil amendment to provide crop N. Although the sludge had 96% of N in organic combination, 20% of total sludge N was released to soil as mineral N over 28 days. N mineralization from the sludge was indistinguishable from that seen for alfalfa shoot in parallel incubations. However, nitrification inhibition was seen for the alfalfa amendment. Soil respiration was low for the sludge treatments compared to the alfalfa treatments, suggesting that carbon substrates in the sludge were less easily broken down. A second incubation experiment indicated that fine fragmentation of the sludge is not necessary to ensure mineralization proceeds. In a greenhouse experiment, sludge N was approximately 25% as available toZea maysL. as NH4NO3. The textile manufacturing sludge offered potential to offset N fertilizer requirement.

Migration can take place primarily during the day or at night, or during both depending on the species. Why the timing of migration varies among species has been the object of much research but the underlying ecological processes are still unclear. Proximally, migration timing may be influenced by the timing of other activities or may be more prevalent in species that migrate over long distances. Adaptive scenarios emphasize the reduction in flight costs at night especially in smaller species and the advantages of travelling in groups during the day to locate staging sites more efficiently. I used phylogenetic independent contrasts to examine these hypotheses in all North American nesting birds. I uncovered 24 evolutionary transitions in migration timing, most of which involved a switch from nocturnal to diurnal migration. Few of these transitions involved a concomitant change in the timing of foraging habits or migration distance. However, species in diurnal clades were larger, travelled in larger flocks and were generally more sociable than their nocturnal counterparts. The results support the hypotheses that a reduction in flight costs and the ability to pool information from companions are associated with migration timing in North American bird species.

A model that accurately simulates the seasonal variation in nitrogen (N) dynamics may represent an important additional tool in N management. The objectives of this study were to evaluate whether seasonal changes in the amount of N that becomes available to a maize crop in a variable landscape can be simulated with LEACHMN and, in particular, to assess the potential value of LEACHMN in estimating N available at the time of the presidedress soil nitrate test (PSNT). Soil mineral N (SMN) and shoot N were measured biweekly over seven growing seasons in corn (Zea Mays L.) grown under conventional tillage in a variable landscape in Southern Ontario, Canada. The model was calibrated using data from 2002 and 2003 from each of five positions in the landscape and then evaluated using data from the 1997–2001 growing seasons. Although the model under-estimated SMN and over-estimated shoot N, the model was more successful in simulating the sum, defined as plant available N (PAN). Simulations of PAN were best at the summit and shoulder positions. The agreement between measured and simulated PAN were poorest early in the season. Although the accuracy of PAN simulations late in the growing season indicates this model has potential value in N management decisions, the errors in simulating SMN early in the season suggest adjustments are required before it can be used, along with other tools, as a substitute for the PSNT in cool humid environments. Key words: Soil mineral N, Plant available N, variable landscapes, LEACHMN

To evaluate and compare nasal mucosal contact, septal deviation and caudal aberrant nasal turbinates in brachycephalic and normocephalic dogs using computed tomography.Dogs without nasal disease and having undergone computed tomography scan of the head (plica alaris to the cribiform plate) were retrospectively selected and divided into brachycephalic and normocephalic groups. Eighteen brachycephalic and 32 normocephalic dogs were included. Anatomic criteria were used to locate predetermined pairs of intranasal structures and nasal mucosal contact was described as present or absent for each site. Septal deviations were identified and measured using angle of septal deviation. Caudal aberrant nasal turbinates were identified and categorised when present.Prevalence of nasal mucosal contact was significantly higher in brachycephalic dogs. No significant difference was seen in prevalence or in angle of septal deviation between groups. Prevalence of caudal aberrant nasal turbinates was significantly higher in brachycephalic dogs.Nasal mucosal contact and caudal aberrant nasal turbinates were significantly more prevalent in brachycephalic dogs than in normocephalic dogs in our study. Computed tomography can be a valuable aid in obtaining data on nasal mucosal contact, caudal aberrant nasal turbinates and septal deviations. Combination of computed tomography with endoscopy and functional airway testing would be useful to further evaluate the correlation between intranasal features and symptoms of brachycephalic airway syndrome.

Maltreated youths in foster care often experience negative developmental and psychological outcomes, which have been linked with poor response inhibition. Recent evidence suggests that childhood maltreatment is also associated with alterations in the neural circuitry underlying response inhibition. However, a burgeoning line of research has begun to explore the mitigating effects of preventive interventions on neural functioning. The current study used event-related functional magnetic resonance imaging to explore the impact of early childhood maltreatment and a preventive intervention on response inhibition in early adolescence. Thirty-six demographically similar adolescents (ages 9-14 years) completed a Go/NoGo task. The sample included nonmaltreated adolescents (n = 14) and maltreated adolescents who were in foster care as preschoolers and randomly assigned to receive services as usual (n = 11) or a preventive intervention, Multidimensional Treatment Foster Care for Preschoolers (n = 11). The groups demonstrated similar behavioral performance but significantly different neural patterns. The maltreated adolescents who received services as usual demonstrated subcortical hypoactivity during successful response inhibition and subcortical hyperactivity during unsuccessful response inhibition. In contrast, the nonmaltreated adolescents and maltreated adolescents who received the intervention exhibited strikingly similar neural patterns during successful response inhibition, but the maltreated adolescents who received the intervention demonstrated prefrontal hypoactivity during unsuccessful response inhibition. These findings offer preliminary evidence that early childhood maltreatment alters the neural patterns underlying response inhibition in early adolescence and that participating in a preventive intervention could mitigate maltreatment-related effects on these neural systems.

Although there are economic and environmental reasons to manage fertilizer-nitrogen (N) more effectively in variable landscapes, the impact of weather and its interaction with soil properties/landscape attributes or management practices has received little attention. The objectives of this study were to assess the magnitude of temporal and spatial variability in soil and plant N in a variable landscape under different management practices and to assess the dependence of their temporal variability on readily available weather variables such as air temperature and rainfall. The experiment was conducted from 1997 to 2003 on a simple slope under three maize (Zea mays L.) based cropping systems. Soil and shoot N were measured through the growing season and the sum used as a measure of plant available N (PAN). Values of PAN varied with year, treatment, landscape position, and year × treatment and year × treatment × position interaction terms. The effects were quantified for each management treatment using multiple regression analyses to relate PAN to soil organic carbon (OC), cumulative degree days (CDD), and cumulative rainfall (CRF) in different periods within the growing season. Plant Available Nitrogen was most strongly influenced by rainfall early in the growing season and exhibited a nonlinear response to OC and CRF. The regression model predicted spatial patterns that were generally stable when applied to historical weather data; PAN increased with OC in 12 of the 15 yr. The analyses illustrates the feasibility of combining soils and weather data to predict N dynamics in variable landscapes.

An understanding of the spatial and temporal variability of N uptake at a landscape scale is required to implement site-specific N management. We determined the spatial variation of in-season N uptake and N nutritional status of corn (Zea mays L.) in a variable landscape in southern Ontario from 1997 to 2001 under three management conditions involving corn under no-tillage or conventional tillage using barley (Hordeum vulgare L.) or barley under-seeded with red clover (Trifolium pratense L.) as the preceding crop and with or without fertilizer N. The aerial dry matter content (DM) of corn and N concentrations in the DM (N i ) were determined at 2-wk intervals. Organic C (OC) content (0-0.3 m) was used as the landscape-based variable to account for the spatial variability of N uptake. Fertilizer N addition, legume incorporation, and tillage had significant positive effects on N uptake, but the magnitude of these effects varied within and among growing seasons. Nitrogen uptake increased with OC content in a quadratic relationship, reaching a maximum at OC content of about 26 g kg -1 . The N nutritional status in the DM, estimated using previously established critical dilution curves, also increased with OC content. However, the nutritional status decreased as the growing season progressed under all management treatments; this decrease was largest at the smallest OC contents. These trends suggest that measurements of plant N early in the season cannot be used in site-specific N management to accurately identify areas of adequate or excess N later in the growing season.

The maximum benefits that may be obtained from site-specific N management will not be realized until we improve our understanding of the spatial variability in plant available nitrogen (PAN) under different soil and crop management practices across the landscape. The objectives of this study were to quantify the influence of soil factors on the spatial and temporal variability of N availability to corn (Zea mays L.) grown under different tillage and legume cover crop conditions. Three management treatments were established on a variable landscape in southern Ontario in 1999, 2000, and 2001: barley (Hordeum vulgare L.) followed by corn under no-tillage, barley followed by corn under spring plowing and secondary tillage, and barley underseeded with red clover (Trifolium pratense L.) that was plowed down the next spring and followed by corn. The PAN contents were measured through the growing seasons and related to soil properties, management, and their interactions using regression analysis. The spatial patterns of PAN were temporally stable, suggesting a temporal consistency in the spatial patterns of factors influencing PAN. The variation in soil temperature among landscape positions was very small, often only 1 to 2°C, and its contribution to the spatial variation in PAN was considered negligible. Soil water made only a small contribution to the variability in PAN because the seasonal average water-filled pore space (SAWFPS) exhibited little variation across the landscape and often fell within the nonlimiting water range (NLWR) for N mineralization. Most of the variation in PAN within a season in this landscape was accounted for by variation in organic carbon (OC) content.

We investigated corn grain yield responses to early-season soil mineral N and plant N content following application of a variety of manures in Eastern Canada. Liquid cattle, liquid swine, straw-bedded poultry, wood-bedded poultry, and solid cattle manures were each applied at 100, 200, and 300 kg N ha-1 prior to planting corn in a field experiment repeated 3 consecutive years. Additional treatments were urea applied at 50, 100, and 150 kg N ha-1, and liquid cattle and solid cattle manures at 200 kg N ha-1 with bedding amendments added to the field before manure spreading. Control plots received no manure, no urea, and no bedding amendment. Part of the ammonium-N applied in manures and a portion of that added as urea was volatilized or immobilized shortly after application and was not recovered as soil mineral N at planting. Across all treatments, soil mineral N in the top 30 cm on Jun. 10 in each year gave a better relationship to corn grain yield than soil mineral N measured at planting or on Jul. 10. Inclusion of data for plant N content on Jun. 10 or Jul. 10 did not improve the regressions. With remarkable consistency across all manure types, across manure rates, and over the three years, similar values for soil mineral N on Jun. 10 in plots given manure at planting had yields typically 0.5-1.0 t ha-1 greater than those in plots given urea at planting. This result indicates that mineralization of N from manure after the time of sidedress N and undetected as soil mineral N on Jun. 10 can contribute to yield increases of corn. Recent manure history should be considered when using soil tests for mineral N that are taken 3-4 wk after planting to calculate sidedress N fertilization. Key words: Sidedress, soil test, slurry, solid, cattle, swine, poultry

Although the effect of soil disturbance on N mineralization has been studied under field conditions, the spatial variation of this effect at the landscape scale has not been investigated. The objective of this study was to determine the spatial variation of the effect of tillage on plant N availability across a variable landscape in southern Ontario and to identify the causal factors. A field experiment was conducted from 1998 to 2001 using two spring tillage operations (no-tillage (NT) and conventional tillage (CT)) prior to planting corn (Zea mays L.) on a field, which was planted to barley (Hordeum vulgare L.) in the preceding season. Tillage treatments were implemented at five positions in the landscape. The corn plants received either 0 or 140 kg N ha−1. Plant N availability was approximated by adding the amount of soil mineral N present in the 0–30 cm depth and N contained in the aerial phytomass in the zero N treatment. The plant available N (PAN) content was significantly higher in the CT treatment than that in the NT treatment during the first 2 months after the tillage operation, with differences ranging from 2.1 to 6.5 mg N kg−1. This effect did not vary with soil properties. In a supplementary laboratory incubation study, which simulated the field tillage operation under controlled conditions, the PAN did not increase in the disturbed soils at any point during the 90-day incubation period. It was hypothesized that the change in the soil physical environment (e.g., soil temperature) could have had a greater influence on the observed differences in the field experiment than the availability of physically protected organic matter in this long-term cultivated field.

Several soil N tests were compared with the one currently used for predicting the N requirement for corn in Ontario. The current test involves a measurement of nitrate (NO3−, 0–30 cm) before N fertilizer sidedressing. The study was done to determine the efficacy of other tests for N fertilizer prediction. The tests chosen varied in the quantity of N “extracted” and included hot KCl-extractable NH4+, anaerobically released NH4+, extractable NH4+ following autoclaving in CaCl2 solution and total N of soil sampled to a depth of 30 cm. The 3-yr study was conducted on a sloped (simple) field site, which provided a wide range in soil organic matter (SOM) contents. A corn crop was grown each year following a barley crop with or without red clover cover crop residues incorporated in the spring and with or without N fertilization. Corn grain yields were obtained at the end of the growing season. Grain yields were lowest at the shoulder and backslope locations and highest at the footslope and toeslope locations. Corn plant shoot biomass and N content and soil mineral (NH4+and NO3−) N (0–30 cm) were measured biweekly to provide an estimate or index of available N. Plant and soil samples were taken at the summit, shoulder, backslope, footslope and toeslope locations providing a wide range of SOM levels, which, in turn, provided a range in available N for comparing the various soil N tests. The increase in estimated available N during the growing season was most rapid in the 120–180 day of year (DOY) period and substantially slower in the 230–260 DOY period. An available N index (AVN) was obtained by averaging the N measured with three plant and soil samples taken in the late August to early September period. Thus, the AVN was determined during a period when the increase in available N was relatively slow. Regressions of corn grain yield (not fertilized with N) on AVN produced R2 values ranging from 0.61 to 0.93. Values of R2 for AVN vs. the soil tests ranged from 0.34 to 0.88 where red clover crop residues were not involved. The AVN values were less correlated with the soil N test values where red clover cover crop residues were incorporated with R2 values ranging from 0.11 to 0.92. It was concluded that the hot KCl test would be a suitable alternative to the currently used soil NO3− test because of relatively simple soil sample preparations and storage, and analytical procedures. Key words: Soil N tests, corn, available N index, soil organic matter, landscape location

One field and two laboratory experiments were conducted to determine the relative magnitude and pattern of N2O production from several granular N fertilizers including urea, ammonium nitrate, calcium nitrate, ammonium sulfate and, in a laboratory experiment, monoammonium and diammonium phosphates. Several parameters, in particular soil water content, were studied for their roles in N2O production with these fertilizers. The field experiment was conducted at the Elora Research Station (20 km north of Guelph) on Conestoga silt loam during July on a site previously cropped to barley. Three methods were employed to assess N2O production following N fertilizer treatments in the field experiment, viz., soil cover, soil core and profile distribution. The data with each method revealed that incorporated urea produced the greatest quantity of N2O especially in the first few days following application. Shortly after urea application and incorporation (10 cm), N2O was detected at a depth of 50 cm indicating gas produced in the tilled layer was transported to lower depths. Data obtained with the intact core method showed that nitrification preceeded denitrification as the source of N2O produced during a wetting event as air-filled porosity decreased from 65% to less than 50%, respectively. The laboratory experiments showed that under aerobic conditions N2O production was generally greater with urea than the other N fertilizers. The greater production of N2O with urea was associated with N2O-accumulation. In the second laboratory experiment, saturating the soil following 14 d of aerobic incubation showed enhanced N2O production with ammonium phosphate fertilizers. Our findings indicate refinement of methods to predict N2O emissions based on N fertilizer source use and moisture can reduce uncertainties in national estimates of N2O emissions from agricultural soils. Key words: Nitrous oxide production, nitrogen fertilizers, soil atmosphere profiles, nitrification, denitrification, air-filled porosity

The usefulness of soil nitrogen (N) tests or indices for predicting crop N requirements has been controversial. This paper shows how the relationship between soil indices and total soil N varies using simple linear regressions. The soil N indices included measurement of extractable NH4 + following autoclaving or anaerobic incubation, or following “hot” (100°C) KCl extraction. Also, extractable NO3 − levels sampled four times during the early growing season (May/June) were correlated to total N. Total soil N was considered to be a relatively stable “bench mark” for this study. Soil samples (0–30 cm) were collected from field trials that focused on response of corn to N with different red clover cover crop management practices on different landscape locations over a 3-year period. Management practices included comparisons between no tillage and conventional tillage done in either the late fall or spring. It was observed that the correlations between total N and any of the soil N indices were extremely varia...

Several models of vigilance assume that it can be adjusted in response to levels maintained by companions. However, the assumption of visual monitoring of vigilance has received little empirical scrutiny. Various treatments in a laboratory study manipulated the ability of zebra finches (Taenopygia guttata) foraging in pairs to monitor visually the vigilance of companions. In one treatment, the insertion of an uncovered partition allowed members of a pair to monitor, if needed, the vigilance of their companion. The addition of a partial cover to the partition in a further treatment eliminated any visual monitoring of vigilance by companions on either side of the partition while leaving the view from the rest of the cage unaltered. The final treatment, without a partition, allowed the feeding behaviour of unrestricted birds to be examined. As birds spent most of their time feeding or vigilant, feeding rate was considered a proxy for vigilance. After an initial difference in feeding rate across treatments, related perhaps to the novelty associated with the insertion of a partition, birds obtained food at a similar rate whether visual monitoring of vigilance was possible or not and whether individuals were physically separated or not. In agreement with recent empirical and theoretical findings, the study provides little evidence for visual monitoring of vigilance in birds.

Phytoremediation, the use of plant systems for contaminant cleanup, is among the fastest growing areas of environmental remediation research, technology development, and implementation. The practice is facilitated by a number of plant adaptations. First, selected plant species can take up and accumulate certain metals in their shoots at levels that are toxic to ordinary plants (hyperaccumulation). The phenomenon is an evolutionary adaptation of specific plant species to natural metal enrichments; consequently, its occurrence is geographically restricted, and the plant species involved are highly specific with respect to types of metals tolerated. Other plant species can take up, metabolize and thereby detoxify certain organic contaminants in their shoots, or cause their transformations through substances released into their root zones (rhizospheres). The extent to which an organic contaminant may be translocated in plants is determined largely by its partitioning into lipid phases (its lipophilicity), while rhizo-sphere transformations are determined largely by types and amounts of plant exudations, and microbial populations that are stimulated by these exudates. Interactions between plant systems and contaminants that can facilitate phytoremediation are complex, and complicated further by strong influences of climate, particularly temperature, and matrix factors such as nature and reactivity of surfaces, pH, and oxidation-reduction statuses. The ways in which the various factors interact to render a contaminant more or less susceptible to phytoremediation are discussed, with the objective of providing information needed for decision making when considering phytoremediation for the cleanup of particular contaminants.

Environmental regulators and other stakeholders prefer cleanup technologies that are successful, cost effective, and not disruptive to a site. Phytoremediation offers an appealing in situ option to managers of remediation projects. Remediation project managers and teams must be experienced and work closely together. For moderately water soluble organic contaminates, it may be possible to utilize plant species that can translocate and metabolize a contaminant within their shoots. For highly lipophilic compounds, a phytoremediation strategy would best focus on stimulation of biodegradation within the root zone of plants. Metal hyperaccumulator plant species have demonstrated successful growth under high enrichments of specific metals. However, while there is promise for hyperaccumulators concentrating metals, their low biomass suggests total uptake may be low. Genetic manipulations of potential plants may possibly overcome this difficulty, but there are inherent societal concerns and risks. Matrix manipulat...

Canine chronic hepatitis (CCH) is a progressive inflammatory disease of unknown etiology. To characterize the inflammatory infiltrate, 16 dogs with CCH were selected and classified into three groups based on the stage of fibrosis, as evaluated with Masson's trichrome stain. The inflammatory infiltrate in each liver section was immunohistochemically characterized and evaluated using CD3, lysozyme, lamba and kappa light chain, and alpha-smooth muscle actin antibodies. Numerous breeds were affected, and middle-aged females predominated in this select group. Necroinflammatory activity progressively increased and then waned as the hepatitis progressed to cirrhosis. CD3+ lymphocytes were the most numerous lymphoid cells in dogs with CCH. Degenerate hepatocytes were occasionally surrounded by CD3+ lymphocytes. Necrosis was positively correlated with the number of CD3+ lymphocytes. The lamba and kappa light chain-positive cell infiltrate was variable but generally mild. A positive correlation between the lambda and kappa light chain-positive cells and the portal alpha-smooth muscle actin was found. The number of alpha-smooth muscle actin-positive cells (myofibroblasts) in portal triads and fibrous septa was positively correlated with the stage of fibrosis. In contrast, no correlation was found between the number of lysozyme-positive cells (Kupffer cells) and the stage of fibrosis. These results further support the idea of an immune-mediated process in CCH and suggest that periductular myofibroblasts play an important role in canine liver fibrogenesis.

When foraging in groups, individuals can use the "producer" tactic to locate food patches and the "scrounger" tactic to exploit the food discoveries of companions. Most producer–scrounger models assume that birds are flexible in using tactics in response to changing conditions and that foragers are phenotypically identical. Individual differences and flexibility in tactic use were investigated in zebra finches (Taenopygia guttata) foraging in two flocks of different composition. Birds varied widely in their use of tactics, and individual differences proved consistent both within and between flocks. Significant adjustments in tactic use occurred from one flock to the other. Results suggest that tactic use in zebra finches foraging in small flocks is characterized by consistency and flexibility. Individual differences in tactic use demonstrate the need to examine further the consequences of phenotypic variation in producer–scrounger models.

Stored manures are often considered to be source of nitrous oxide (N2O). A study was done to identify manure characteristics and handling stages related to N2O production. In two laboratory experiments we investigated the production of N2O from several animal manures collected at different stages of manure handling or locations in stored-manure systems. Denitrifying enzyme activity, denitrification and CO2 production rates and chemical and fibre characteristics of manure samples were also determined. Most samples had low rates of N2O production. Exceptions were open piles of fresh beef manure and the moist surface layer near the base of an open pile of poultry manure. Production of N2O was most highly correlated with nitrite plus nitrate (NO2− + NO3−) content of manure regardless of whether results were expressed on a wet or a dry weight basis. Denitrification was the most probable source of N2O because N2O production with acetylene and denitrifying enzyme activities was higher than N2O production without acetylene. Stored manure is potentially an important source of N2O emissions, particularly when storage conditions are conducive to formation of (NO2− + NO3−). Key words: Nitrous oxide production, denitrification, denitrifying enzyme activity, manure