Carbon Source Reduction Postpones Autumn Leaf Senescence in a Widespread Deciduous Tree.

The growing-season length of temperate and boreal trees has a strong effect on the global carbon cycle. Yet, a poor understanding of the drivers of phenological processes, such as autumn leaf senescence in deciduous trees, limits our capacity to estimate growing-season lengths under climate change. While temperature has been shown to be an important driver of autumn leaf senescence, carbon source-sink dynamics have been proposed as a mechanism that could help explain variation of this important process. According to the carbon sink limitation hypothesis, senescence is regulated by the interplay between plant carbon source and sink dynamics, so that senescence occurs later upon low carbon inputs (source) and earlier upon low carbon demand (sink). Here, we manipulated carbon source-sink dynamics in birch saplings (Betula pendula) to test the relevance of carbon sink limitation for autumn leaf senescence and photosynthetic decline in a widespread deciduous tree. Specifically, we conducted a gradient of leaf and bud removal treatments and monitored the effects on autumnal declines in net photosynthesis and the timing of leaf senescence. In line with the carbon sink limitation hypothesis, we observed that leaf removal tended to increase total leaf-level autumn photosynthesis and delayed the timing of senescence. Conversely, we did not observe an effect of bud removal on either photosynthesis or senescence, which was likely caused by the fact that our bud removal treatment did not considerably affect the plant carbon sink. While we cannot fully rule out that the observed effect of leaf removal was influenced by possible treatment-level differences in leaf age or soil resource availability, our results provide support for the hypothesis of carbon sink limitation as a driver of growing-season length and move the scientific field closer to narrowing the uncertainty in climate change predictions.

Neurocognitive Correlates of Successful Treatment of PTSD in Female Veterans.

BACKGROUND: The influence of psychotherapy on neurocognition in post-traumatic stress disorder (PTSD) has not been examined methodically. This is despite evidence that pre-treatment learning and memory has been associated with treatment success and that executive function theories emphasize weak executive functions (especially inhibition/switching) are associated with PTSD. OBJECTIVES: To determine (1) if higher pre-treatment learning/memory, inhibition/switching, or both predict treatment success; and (2) if treatment success is associated with specific improvement in inhibition/switching and not learning/memory or working memory, another aspect of executive function. METHODS: Pre-treatment neurocognition and neurocognitive changes (inhibition/switching, learning/memory, working memory) were examined in female veterans with PTSD. They were evaluated before and after 16-weeks of group psychotherapy for PTSD that included three counterbalanced modules (cognitive restructuring therapy, exposure therapy, skills training) with fidelity checks for therapist adherence. RESULTS: Only pre-treatment learning/memory predicted better treatment outcome. Treatment success was associated with improvement in inhibition/switching only, even after controlling for mild traumatic brain injury, and changes in depressive symptoms, working memory, and learning/memory. CONCLUSIONS: Our finding that learning/memory predicted treatment success is consistent with previous studies. We extended these studies by showing that the effect was restricted to learning/memory, which is contrary to the executive function theory of PTSD. In contrast, the fact that only inhibition/switching significantly improved with better treatment success is consistent with its potential importance in maintaining PTSD symptoms. Future research should determine whether inhibition/switching abilities are a risk for development and maintenance of PTSD or whether such abilities have a broader reciprocal relationship with PTSD symptom change. (JINS, 2016, 22, 643-651).

Group-delivered cognitive/exposure therapy for PTSD in women veterans: A randomized controlled trial.

OBJECTIVE: Group delivery of posttraumatic stress disorder (PTSD) treatment has several advantages, however group research is not comparable to individual trials. This study extends the group literature by improving methodology in examining the efficacy of a 3-module (cognitive, exposure, skills) group treatment for PTSD, establishes a format for the delivery of group exposure therapy, and compares 3 treatment modules within the group. METHOD: Eighty-six Operation Enduring Freedom (OEF)/Operation Iraqi Freedom (OIF) women veterans were randomized to a 16-week, 3-member group treatment (Tx) or a waitlist (WL) condition. The primary (Clinician Administered PTSD Scale [CAPS]) and secondary (Medical Outcomes Study Short Form-36 [SF-36], Quality of Life Inventory [QOLI], and PTSD Checklist [PCL]) outcome measures were administered at baseline, post Tx/WL, and at 3- and 6-months post Tx (PCL additionally at pre/post for each treatment module). RESULTS: PTSD symptoms significantly improved in Tx arm participants (p < .001, ES = 1.72; unit of analysis group: n = 14), as did mental and physical life functioning (SF-36; p < .001), and quality of life (QOLI; p < .001). The WL significantly improved on the SF-36 (mental; p = .04) and QOLI (p = .02). Clinical improvement (CAPS) in the Tx arm reflected a treatment response (≥10-point decrease) in 77% and loss of PTSD diagnosis (<45) in 52% of participants, comparable to individual prolonged exposure (PE) treatment. Finally, PCL scores significantly lowered in exposure and cognitive modules. CONCLUSIONS: This study supports the use of group format for PTSD with 3 modules using improved methodology, with a novel, 3-member group which allows repeated in-session weekly imaginal exposures. The results suggest future examination of group delivered PE. (PsycINFO Database Record

The neurocognitive performance of female veterans with posttraumatic stress disorder.

Neurocognitive problems are common with posttraumatic stress disorder (PTSD) and are important to understand because of their association with the success of PTSD treatment and its potential neural correlates. To our knowledge, this is the first neurocognitive study in an all-female U.S. veteran sample, some of whom had PTSD. We examined neurocognitive performance and assessed whether learning deficits, common in PTSD, were associated with executive functioning. Veterans with PTSD (n = 56) and without (n = 53) were evaluated for psychiatric and neurocognitive status. The PTSD group had a lower estimated IQ (d = 0.53) and performed more poorly on all neurocognitive domains (d range = 0.57-0.88), except verbal retention (d = 0.04). A subset of the 2 groups that were matched on IQ and demographics similarly demonstrated poorer performance for the PTSD group on all neurocognitive domains (d range = 0.52-0.79), except verbal retention (d = 0.15). Within the PTSD group, executive functioning accounted for significant variance in verbal learning over and above IQ and processing speed (ΔR(2) = .06), as well as depression (ΔR(2) = .07) and PTSD severity (ΔR(2) = .06). This study demonstrated that female veterans with PTSD performed more poorly than females without PTSD on several neurocognitive domains, including verbal learning, processing speed, and executive functioning. Replication of these results using a control group of veterans with more similar trauma exposure, history of mild traumatic brain injury, and psychiatric comorbidities would solidify these findings.

Patterns and determinants of breast and cervical cancer non-screening among Appalachian women.

Breast and cervical cancer account for nearly one-third of new cancer cases and one-sixth of cancer deaths. Cancer, the second leading cause of all deaths in the United States, will claim the lives of nearly 800,000 women this year, which is particularly unfortunate because effective modes of early detection could significantly reduce mortality from breast and cervical cancer. Researchers examined patterns of non-screening among Appalachian women. In-person interviews were conducted with 222 Appalachian women who fell outside of screening recommendations for timing of Pap tests and mammograms. These women, from six Appalachian counties, were participating in a group-randomized, multi-component trial aimed at increasing adherence to cancer screening recommendations. Results indicated that participants who were rarely or never screened for breast cancer were also likely to be rarely or never screened for cervical cancer. In addition, four key barriers were identified as independently and significantly associated with being rarely or never screened for both cervical and breast cancer. An improved understanding of cancer screening patterns plus the barriers underlying lack of screening may move researchers closer to developing effective interventions that facilitate women's use of screening.