1,299 research outputs found

    Impaired contextual modulation of memories in PTSD: an fMRI and psychophysiological study of extinction retention and fear renewal

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    Post-traumatic stress disorder (PTSD) patients display pervasive fear memories, expressed indiscriminately. Proposed mechanisms include enhanced fear learning and impaired extinction or extinction recall. Documented extinction recall deficits and failure to use safety signals could result from general failure to use contextual information, a hippocampus-dependent process. This can be probed by adding a renewal phase to standard conditioning and extinction paradigms. Human subjects with PTSD and combat controls were conditioned (skin conductance response), extinguished, and tested for extinction retention and renewal in a scanner (fMRI). Fear conditioning (light paired with shock) occurred in one context, followed by extinction in another, to create danger and safety contexts. The next day, the extinguished conditioned stimulus (CS+E) was re-presented to assess extinction recall (safety context) and fear renewal (danger context). PTSD patients showed impaired extinction recall, with increased skin conductance and heightened amygdala activity to the extinguished CS+ in the safety context. However, they also showed impaired fear renewal; in the danger context, they had less skin conductance response to CS+E and lower activity in amygdala and ventral-medial prefrontal cortex compared with combat controls. Control subjects displayed appropriate contextual modulation of memory recall, with extinction (safety) memory prevailing in the safety context, and fear memory prevailing in the danger context. PTSD patients could not use safety context to sustain suppression of extinguished fear memory, but they also less effectively used danger context to enhance fear. They did not display globally enhanced fear expression, but rather showed a globally diminished capacity to use contextual information to modulate fear expression

    Channelized melt flow in downwelling mantle: Implications for 226Ra-210Pb disequilibria in arc magmas

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    We present the results of an analytical model of porous flow of viscous melt into a steadily dilating ‘‘channel’’ (defined as a cluster of smaller veins) in downwelling subarc mantle. The model predicts the pressure drop in the mantle wedge matrix surrounding the channel needed to drive melt flow as a function of position and time. Melt is sucked toward the dilatant region at a near-constant velocity (105 s1) until veins comprising the channel stop opening (t = t). Fluid elements that complete their journey within the time span t < t arrive at a channel. Our results make it possible to calculate the region of influence sampled by melt that surrounds the channel. This region is large compared to the model size of the channelized region driving flow. For a baseline dilation time of 1 year and channel half width of 2 m, melt can be sampled over an 80-m radius and has the opportunity to sample matrix material with potentially contrasting chemistry on geologically short timescales. Our mechanical results are consistent with a downgoing arc mantle wedge source region where melting and melt extraction by porous flow to a channel network are sufficiently rapid to preserve source-derived 238U-230Th-226Ra, and potentially also 226 Ra-210Pb, disequilibria, prior to magma ascent to the surface. Since this is the rate-determining step in the overall process, it allows the possibility that such short-lived disequilibria measured in arc rocks at the surface are derived from deep in the mantle wedge. Stresses due to partial melting do not appear capable of producing the desired sucking effect, while the order of magnitude rate of shear required to drive dilation of 107 s1 is much larger than values resulting from steady state subduction. We conclude that local deformation rates in excess of background plate tectonic rates are needed to ‘‘switch on’’ the dilatant channel network and to initiate the sucking effect

    Identifying house price diffusion patterns among Australian state capital cities

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    Prior research supports the proposition that house price diffusion shows a ripple effect along the spatial dimension. That is, house price changes in one region would reflect in subsequent house price changes in other regions, showing certain linkages among regions. Using the vector autoregression model and the impulse response function, this study investigates house price diffusion among Australia\u27s state capital cities, examining the response of one market to the innovation of other markets and determining the lagged terms for the maximum absolute value of the other markets\u27 responses. The results show that the most important subnational markets in Australia do not point to Sydney, rather towards Canberra and Hobart, while the Darwin market plays a role of buffer. The safest markets are Sydney and Melbourne. This study helps to predict house price movement trends in eight capital cities.<br /

    A framework for models of movement in geographic space

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    This article concerns the theoretical foundations of movement informatics. We discuss general frameworks in which models of spatial movement may be developed. In particular, the article considers the object–field and Lagrangian–Eulerian dichotomies, and the SNAP/SPAN ontologies of the dynamic world, and classifies the variety of informatic structures according to these frameworks. A major challenge is transitioning between paradigms. Usually data is captured with respect to one paradigm but can usefully be represented in another. We discuss this process in formal terms and then describe experiments that we performed to show feasibility. It emerges that observational granularity plays a crucial role in these transitions

    Adaptive School-based Implementation of CBT (ASIC): clustered-SMART for building an optimized adaptive implementation intervention to improve uptake of mental health interventions in schools

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    Abstract Background Depressive and anxiety disorders affect 20–30% of school-age youth, most of whom do not receive adequate services, contributing to poor developmental and academic outcomes. Evidence-based practices (EBPs) such as cognitive behavioral therapy (CBT) can improve outcomes, but numerous barriers limit access among affected youth. Many youth try to access mental health services in schools, but school professionals (SPs: counselors, psychologists, social workers) are rarely trained adequately in CBT methods. Further, SPs face organizational barriers to providing CBT, such as lack of administrative support. Three promising implementation strategies to address barriers to school-based CBT delivery include (1) Replicating Effective Programs (REP), which deploys customized CBT packaging, didactic training in CBT, and technical assistance; (2) coaching, which extends training via live supervision to improve SP competence in CBT delivery; and (3) facilitation, which employs an organizational expert who mentors SPs in strategic thinking to promote self-efficacy in garnering administrative support. REP is a relatively low-intensity/low-cost strategy, whereas coaching and facilitation require additional resources. However, not all schools will require all three strategies. The primary aim of this study is to compare the effectiveness of a school-level adaptive implementation intervention involving REP, coaching, and facilitation versus REP alone on the frequency of CBT delivered to students by SPs and student mental health outcomes. Secondary and exploratory aims examine cost-effectiveness, moderators, and mechanisms of implementation strategies. Methods Using a clustered, sequential multiple-assignment, randomized trial (SMART) design, ≥ 200 SPs from 100 schools across Michigan will be randomized initially to receive REP vs. REP+coaching. After 8 weeks, schools that do not meet a pre-specified implementation benchmark are re-randomized to continue with the initial strategy or to augment with facilitation. Discussion EBPs need to be implemented successfully and efficiently in settings where individuals are most likely to seek care in order to gain large-scale impact on public health. Adaptive implementation interventions hold the promise of providing cost-effective implementation support. This is the first study to test an adaptive implementation of CBT for school-age youth, at a statewide level, delivered by school staff, taking an EBP to large populations with limited mental health care access. Trial registration NCT03541317 —Registered on 29 May 2018 on ClinicalTrials.gov PRShttps://deepblue.lib.umich.edu/bitstream/2027.42/145606/1/13012_2018_Article_808.pd

    Humanized Mouse Model of Ovarian Cancer Recapitulates Patient Solid Tumor Progression, Ascites Formation, and Metastasis

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    Ovarian cancer is the most common cause of death from gynecological cancer. Understanding the biology of this disease, particularly how tumor-associated lymphocytes and fibroblasts contribute to the progression and metastasis of the tumor, has been impeded by the lack of a suitable tumor xenograft model. We report a simple and reproducible system in which the tumor and tumor stroma are successfully engrafted into NOD-scid IL2Rγnull (NSG) mice. This is achieved by injecting tumor cell aggregates derived from fresh ovarian tumor biopsy tissues (including tumor cells, and tumor-associated lymphocytes and fibroblasts) i.p. into NSG mice. Tumor progression in these mice closely parallels many of the events that are observed in ovarian cancer patients. Tumors establish in the omentum, ovaries, liver, spleen, uterus, and pancreas. Tumor growth is initially very slow and progressive within the peritoneal cavity with an ultimate development of tumor ascites, spontaneous metastasis to the lung, increasing serum and ascites levels of CA125, and the retention of tumor-associated human fibroblasts and lymphocytes that remain functional and responsive to cytokines for prolonged periods. With this model one will be able to determine how fibroblasts and lymphocytes within the tumor microenvironment may contribute to tumor growth and metastasis, and will make it possible to evaluate the efficacy of therapies that are designed to target these cells in the tumor stroma
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