359 research outputs found

    Dwarf mistletoe-pandora moth interaction and its contribution to ponderosa pine mortality in Arizona

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    The interaction between Southwestern dwarf mistletoe, Arceuthobtum vaginalum subspecies cryptopodum, infestation and defoliation by the pandora moth, Coloradia pandora pandora , on the Kaibab Plateau in Arizona was evaluated. Heavy defoliation of ponderosa pine, Pinus ponderosa, in 1979 and 1981 resulted in mortality of individual trees in areas of heavy dwarf mistletoe infestation. Postmortem evaluation of ponderosa pines indicated that dead trees had a significantly higher dwarf mistletoe rating than did nearby paired live trees. Of 25 tree pairs evaluated, only two live trees had higher dwarf mistletoe ratings than the paired dead tree. Mean dwarf mistletoe ratings were:live trees 2.9, dead trees 4.6 (6 class dwarf mistletoe rating system). Implications for management of the pandora moth are discussed

    A Morphometric Analysis of Arceuthobium campylopodum and Arceuthobium divaricatum (Viscaceae)

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    Although the classification of pinyon dwarf mistletoe (Arceuthobium divaricatum, Viscaceae) has not been controversial to any extent since Engelmann described it in 1878, a recent taxonomic treatment has included this species in western dwarf mistletoe (A. campylopodum). While pinyon dwarf mistletoe is only known to parasitize pinyon pines (Pinus subsection Cembroides), western dwarf mistletoe as it has been known since the late 1800s is a principal parasite of Pinus ponderosa and P. jeffreyi and has never been observed parasitizing pinyon pines. With reservations about the recent classification of pinyon dwarf mistletoe and its treatment under A. campylopodum, we undertook this study to examine in detail the morphological characteristics of pinyon dwarf mistletoe and compare them with those of western dwarf mistletoe. Pinyon and western dwarf mistletoe populations were sampled throughout most of their geographic ranges and morphological traits including plant, flower, fruit, and seed dimensions were measured. Thereafter, we compared morphological characteristics between A. campylopodum and A. divaricatum using univariate and multivariate statistics to determine significant differences among morphologies of both male and female plants. Our analyses clearly demonstrated that pinyon and western dwarf mistletoe are morphologically distinct as originally proposed by G. Engelmann in the late 19th century. Furthermore, the host affinities of the two taxa clearly distinguish them from each other. Therefore, we recommend that A. campylopodum and A. divaricatum continue to be classified as separate species. Morphological differences between these species are summarized and a key is provided for use in their field identification

    Comparison of Two Roadside Survey Procedures for Dwarf Mistletoes on the Sawtooth National Forest, Idaho

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    Two roadside surveys were conducted for dwarf mistletoes parasitizing lodgepole pine and Douglas-fir on the Sawtooth National Forest, Idaho. One survey used variable-radius plots located less than 150 m from roads. The 2nd survey used variable-radius plots established at 200-m intervals along 1600-m transects run perpendicular to the same roads. Estimates of the incidence (percentage of trees infected and percentage of plots infested) and severity (average dwarf mistletoe rating) for both lodgepole pine and Douglas-fir dwarf mistletoes were not significantly different for the 2 survey methods. These findings are further evidence that roadside-plot surveys and transect-plot surveys conducted away from roads provide similar estimates of the incidence of dwarf mistletoes for large forested areas

    Comparison of Two Roadside Survey Procedures for Dwarf Mistletoes on the Sawtooth National Forest, Idaho

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    Two roadside surveys were conducted for dwarf mistletoes parasitizing lodgepole pine and Douglas-fir on the Sawtooth National Forest, Idaho. One survey used variable-radius plots located less than 150 m from roads. The 2nd survey used variable-radius plots established at 200-m intervals along 1600-m transects run perpendicular to the same roads. Estimates of the incidence (percentage of trees infected and percentage of plots infested) and severity (average dwarf mistletoe rating) for both lodgepole pine and Douglas-fir dwarf mistletoes were not significantly different for the 2 survey methods. These findings are further evidence that roadside-plot surveys and transect-plot surveys conducted away from roads provide similar estimates of the incidence of dwarf mistletoes for large forested areas

    The anterior thalamic nuclei and nucleus reuniens: So similar but so different

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    Two thalamic sites are of especial significance for understanding hippocampal – diencephalic interactions: the anterior thalamic nuclei and nucleus reuniens. Both nuclei have dense, direct interconnections with the hippocampal formation, and both are directly connected with many of the same cortical and subcortical areas. These two thalamic sites also contain neurons responsive to spatial stimuli while lesions within these two same areas can disrupt spatial learning tasks that are hippocampal dependent. Despite these many similarities, closer analysis reveals important differences in the details of their connectivity and the behavioural impact of lesions in these two thalamic sites. These nuclei play qualitatively different roles that largely reflect the contrasting relative importance of their medial frontal cortex interactions (nucleus reuniens) compared with their retrosplenial, cingulate, and mammillary body interactions (anterior thalamic nuclei). While the anterior thalamic nuclei are critical for multiple aspects of hippocampal spatial encoding and performance, nucleus reuniens contributes, as required, to aid cognitive control and help select correct from competing memories

    Separate cortical and hippocampal cell populations target the rat nucleus reuniens and mammillary bodies

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    Nucleus reuniens receives dense projections from both the hippocampus and the frontal cortices. Reflecting these connections, this nucleus is thought to enable executive functions, including those involving spatial learning. The mammillary bodies, which also support spatial learning, again receive dense hippocampal inputs, as well as lighter projections from medial frontal areas. The present study, therefore, compared the sources of these inputs to nucleus reuniens and the mammillary bodies. Retrograde tracer injections in rats showed how these two diencephalic sites receive projections from separate cell populations, often from adjacent layers in the same cortical areas. In the subiculum, which projects strongly to both sites, the mammillary body inputs originate from a homogenous pyramidal cell population in more superficial levels, while the cells that target nucleus reuniens most often originate from cells positioned at a deeper level. In these deeper levels, a more morphologically diverse set of subiculum cells contributes to the thalamic projection, especially at septal levels. While both diencephalic sites also receive medial frontal inputs, those to nucleus reuniens are especially dense. The densest inputs to the mammillary bodies appear to arise from the dorsal peduncular cortex, where the cells are mostly separate from deeper neurons that project to nucleus reuniens. Again, in those other cortical regions that innervate both nucleus reuniens and the mammillary bodies, there was no evidence of collateral projections. The findings support the notion that these diencephalic nuclei represent components of distinct, but complementary, systems that support different aspects of cognition

    Projections of the insular cortex to orbitofrontal and medial prefrontal cortex. A tracing study in the rat

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    The dense fiber pathways that connect the insular cortex with frontal cortices are thought to provide these frontal areas with interoceptive information, crucial for their involvement in executive functions. Using anterograde neuroanatomical tracing, we mapped the detailed organization of the projections from the rat insular cortex to its targets in orbitofrontal (OFC) and medial prefrontal (mPFC) cortex. In OFC, main insular projections distribute to lateral and medial parts, avoiding ventral parts. Whereas projections from the primary gustatory cortex densely innervate dorsolateral OFC, likely corresponding to what in primates is known as the secondary gustatory cortex, these projections avoid mPFC. Instead, mPFC is targeted almost exclusively by projections from agranular fields of the insular cortex. Finally, “parietal” domains of the insular cortex project specifically to the dorsolateral OFC, and strongly innervate ventral portions of mPFC, i.e., the dorsal peduncular cortex

    Economic evaluation alongside a randomized controlled trial of blended cognitive-behavioral therapy for patients suffering from major depressive disorder

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    OBJECTIVE: This study aimed to investigate the cost-effectiveness of blended cognitive-behavioral therapy (CBT) compared to standard CBT for adult patients suffering from major depressive disorder (MDD). DESIGN: A cost-utility analysis alongside the randomized controlled ENTER trial. SETTING: Center for Telepsychiatry, Mental Health Services in the Region of Southern Denmark, Denmark. PARTICIPANTS: The study included 76 patients suffering from MDD. INTERVENTIONS: The patients in the intervention group received blended CBT treatment comprising a combination of online modules and face-to-face consultations with a psychologist. The patients in the control group received standard CBT treatment, that is, solely face-to-face consultations with a psychologist. The treatment period was 12 weeks. OUTCOME MEASURES: Cost-effectiveness was reported as incremental cost-effectiveness ratio. A micro-costing approach was applied to evaluate the savings derived. Changes in quality-adjusted life-years (QALYs) were estimated using the EuroQol 5-Dimensions 5-Levels questionnaire at the baseline and the six-month follow-up. RESULTS: Data for 74 patients were included in the primary analysis. The adjusted QALY difference between blended CBT and standard CBT was −0.0291 (95% CI: −0.0535 to −0.0047), and the adjusted difference in costs was -£226.32 (95% CI: −300.86 to −151.77). Blended CBT was estimated to have a 6.6% and 3.1% probability of being cost-effective based on thresholds of £20,000 and £30,000. CONCLUSION: Compared to standard CBT, blended CBT represents a cost-saving but also a loss in QALYs for patients suffering from MDD. However, results should be carefully interpreted, given the small sample size. Future research involving larger replication studies focusing on other aspects of blended CBT with more patient involvement is advised. TRIAL REGISTRATION NUMBER: ClinicalTrial.gov: S-20150150
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