Density-Dependent Effects on Microhabitat Selection and Activity of Two Species of Larval Ambystoma Salamanders

To be able to distinguish unnatural amphibian declines from natural population fluctuations we need a better understanding of the mechanisms that affect amphibian community structure. Larval pond-breeding salamanders exhibit density-dependent effects on population parameters, but little is known of the effect of density on behaviors that mediate interactions. Two species, Amby1toma tigrinum (tiger salamander) and A. laterale (blue-spotted salamander), were evaluated in laboratory aquaria for intraspecific and interspecific interactions that affect microhabitat selection and activity. Microhabitat selection was studied by partitioning containers into microhabitats that either contained or lacked refuges, and movement was recorded over a hexagonal grid to determine activity during periods of observation. Both species altered microhabitat preferences and activity levels when they shared tanks with con- or heterospecifics. These density-dependent behavioral changes may indicate that fluctuations in population densities result in behavioral responses that may contribute to coexistence

Sustaining Clinician Penetration, Attitudes and Knowledge in Cognitive-Therapy for Youth Anxiety

Background: Questions remain regarding the sustainment of evidence-based practices following implementation. The present study examined the sustainment of community clinicians’ implementation (i.e., penetration) of cognitive-behavioral therapy, attitudes toward evidence-based practices, and knowledge of cognitive-behavioral therapy for youth anxiety two years following training and consultation in cognitive-behavioral therapy for youth anxiety. Methods: Of the original 115 participants, 50 individuals (43%) participated in the two-year follow-up. A t- test examined sustainment in penetration over time. Hierarchical linear modeling examined sustainment in knowledge and attitudes over time. Time spent in consultation sessions was examined as a potential moderator of the change in knowledge and attitudes. Results: Findings indicated sustained self-reported penetration of cognitive-behavioral therapy for anxious youth, with low fidelity to some key CBT components (i.e., exposure tasks). Follow-up knowledge was higher than at baseline but lower than it had been immediately following the consultation phase of the study. Belief in the utility of evidence-based practices was sustained. Willingness to implement an evidence-based practice if required to do so, appeal of evidence-based practices, and openness toward evidence-based practices were not sustained. Participation in consultation positively moderated changes in knowledge and some attitudes. Conclusions: Sustainment varied depending on the outcome examined. Generally, greater participation in consultation predicted greater sustainment. Implications for future training include higher dosages of consultation

Activation mapping in patients with coronary artery disease with multiple ventricular tachycardia configurations: Occurrence and therapeutic implications of widely separate apparent sites of origin

Catheter or intraoperative activation mapping studies, or both, were performed in 17 patients with coronary artery disease with two to four distinct configurations of ventricular tachycardia, resistant to a mean of 12.1 ± 6.0 antiarrhythmic drug trials per patient. Mapping studies were performed to guide anticipated surgical ablation of arrhythmias. Activation map data were adequate to determine sites of origin of 30 (64%) of 47 observed tachycardia configurations. These 30 ventricular tachycardias (26 observed clinically) were mapped to 22 separate endocardial sites of origin. Sites of origin of distinct tachycardias were identical or closely adjacent (within 3 cm) in six patients and widely separate (≥4 cm) in eight patients (47% of the group). Activation maps were not adequate to determine sites of origin of 17 (36%) of the 47 tachycardias, including all configurations in three patients.Fifteen patients underwent surgery for control of ventricular tachycardia: aggressive, map-guided endocardial resection (mean 26.5 ± 14.2 cm2) in 12 patients with identified sites of tachycardia origin and extensive resection of visible endocardial scar (2 patients) or encircling endocardial ventriculotomy (1 patient) in those in whom the sites of origin of all clinical tachycardias remained undetermined. Two inoperable patients were treated with amiodarone. During postoperative electrophysiologic tests (11 of 13 surgical survivors), ventricular tachyarrhythmias were initially uninducible in only 4 of 11 patients. However, in two patients only nonclinical arrhythmias (ventricular flutter) were induced. Six (21%) of 29 clinical tachycardias whose sites of origin were either not determined or not resected (right septum or papillary muscle) remained inducible in five patients. Using previously ineffective antiarrhythmic drugs, initially inducible arrhythmias became uninducible (two patients), or harder to induce than preoperatively (five patients). As a result of surgical resections alone or in combination with previously ineffective drugs (and amiodarone in two inoperable patients), there were no recurrences of ventricular tachycardia in 14 (93%) of 15 patients discharged during 19.0 ± 14.3 months of follow-up study.Thus, activation mapping may commonly reveal separate apparent sites of origin for clinically observed, morphologically distinct, highly drug-refractory ventricular tachycardias in patients with coronary artery disease with multiple tachycardia configurations. Extensive surgical resection of identified sites of origin may be required to ablate arrhythmias in these patients. Tachycardias whose sites of origin are not identified or resected may remain inducible. However, aggressive surgical excisions may alter regions involved in the genesis or maintenance of these arrhythmias because they become more difficult to induce postoperatively, more amenable to drug therapy and do not recur