521 research outputs found

    Determination of Flaw Growth Characteristics of Ti-6Al-4V Sheet in the Solution-Treated and Aged Condition

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    The specific experimental investigation undertaken was designed to answer these questions on Ti-6Al-4V in the solution treated and aged condition. The defect growth and fracture characteristics were studied in parent (unwelded) and welded sheet material. The results of the study indicate that cryogenic proof testing will screen smaller size defects than proof testing at ambient conditions. However some unusual crack growth behavior during the proof test simulation suggests that some further study be made of stress and time duration effects

    Predictors of response to cognitive-behavioral therapy for body dysmorphic disorder

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    Body dysmorphic disorder (BDD) is a common and distressing or impairing preoccupation with a perceived defect in physical appearance. Individuals with BDD engage in time-consuming rituals to check, hide, or "fix" their appearance or alleviate distress. BDD is associated with substantial psychosocial impairment and high rates of depression, hospitalization, and suicidality. Cognitive-behavioral therapy (CBT) is the treatment of choice for BDD, but not everyone benefits. We examined predictors of CBT-related improvement, an important topic that has received very limited investigation. Treatment was delivered in weekly individual sessions over 18-22 weeks. Results indicated that greater motivation/readiness to change (University of Rhode Island Change Assessment Questionnaire), greater treatment expectancy (Treatment Credibility/Expectancy Questionnaire), and better baseline BDD-related insight (Brown Assessment of Beliefs Scale) significantly predicted better CBT response at posttreatment. Baseline BDD symptom severity and depression did not predict outcome, suggesting that even patients with more severe BDD and depressive symptoms can benefit from CBT for BDD. Efforts should be aimed at enhancing readiness to change and confidence in the treatment at treatment onset as well as addressing the poor insight that often characterizes BDD.R34 MH070490 - NIMH NIH HHSAccepted manuscrip

    Leaf-Level Gas Exchange and Foliar Chemistry of Common Old-Field Species Responding to Warming and Precipitation Treatments.

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    We investigated the shifts in plant carbon (C) and water dynamics by measuring rates of photosynthesis, transpiration, and instantaneous water use efficiency (WUE) in three common species of “old-field” plants—two C3 forb species (Plantago lanceolata and Taraxacum officinale) and one C3 grass species (Elymus repens)—under 12 experimentally altered temperature and precipitation regimes at the Boston Area Climate Experiment (BACE) in Waltham, Massachusetts. We also measured shifts in foliar C and nitrogen (N) content to determine possible changes in plant C/nutrient balance. We hypothesized that the warming treatment would cause an increase in photosynthesis rates, unless water was limiting; therefore, we expected an interactive effect of warming and precipitation treatments. We found that warming and drought reduced leaf-level photosynthesis most dramatically when environmental or seasonal conditions produced soils that were already dry. In general, the plants transpired fastest when soils were wet and slowest when soils were dry. Drought treatments increased WUE relative to plants in the ambient and wet treatments but only during the driest and warmest background conditions. Leaf N concentration increased with warming, thereby indicating that future warming may cause some plants to take up more soil N and/or allocate more N to their leaves, possibly as consequences of increased nutrient availability. There were no significant interactive effects of the warming and precipitation treatments together across all seasons, indicating that responses were not synergistic or ameliorative

    A combined experimental and computational study of the pressure dependence of the vibrational spectrum of solid picene C_22H_14

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    We present high-quality optical data and density functional perturbation theory calculations for the vibrational spectrum of solid picene (C22_{22}H14_{14}) under pressure up to 8 GPa. First-principles calculations reproduce with a remarkable accuracy the pressure effects on both frequency and intensities of the phonon peaks experimentally observed . Through a detailed analysis of the phonon eigenvectors, We use the projection on molecular eigenmodes to unambiguously fit the experimental spectra, resolving complicated spectral structures, in a system with hundreds of phonon modes. With these projections, we can also quantify the loss of molecular character under pressure. Our results indicate that picene, despite a \sim 20 % compression of the unit cell, remains substantially a molecular solid up to 8 GPa, with phonon modes displaying a smooth and uniform hardening with pressure. The Grueneisen parameter of the 1380 cm^{-1} a_1 Raman peak (Îłp=0.1\gamma_p=0.1) is much lower than the effective value (Îłd=0.8\gamma_d=0.8) due to K doping. This is an indication that the phonon softening in K doped samples is mainly due to charge transfer and electron-phonon coupling.Comment: Replaced with final version (PRB

    Fatigue behavior of materials for the sst - electron fractographic studies final report

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    Electron microscopic fractography to determine fatigue behavior of materials for supersonic transport - titanium, aluminum, molybdenum, and vanadiu

    Detection of fixed points in spatiotemporal signals by clustering method

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    We present a method to determine fixed points in spatiotemporal signals. A 144-dimensioanl simulated signal, similar to a Kueppers-Lortz instability, is analyzed and its fixed points are reconstructed.Comment: 3 pages, 3 figure

    Are elites really less fair-minded?

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    US power ‘elites’ are substantially less fair-minded than ‘non-elite’ general populations claims a study by Ray Fisman and coauthors [Science 349, 6254 (2015)]. This supposedly explains why US governments, run by people less fair than the citizens they represent, have been uninclined to tackle inequality. We critically replicated the study, because different experimental protocols for ‘elites’ (interactive variants) and ‘non-elites’ (standard dictator games) were used to measure preferences. We find that the protocol potpourri drove the conclusion: under standard protocols, we find no significant class differences, if any opposite ones. Our work highlights the risk of producing false positives when ex post results appear invitingly plausible

    Combat‐Related Posttraumatic Stress Disorder and Comorbid Major Depression in U.S. Veterans: The Role of Deployment Cycle Adversity and Social Support

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    Posttraumatic stress disorder (PTSD) and major depressive disorder (MDD) commonly co‐occur in combat veterans, and this comorbidity has been associated with higher levels of distress and more social and economic costs compared to one disorder alone. In a secondary analysis of a multisite randomized controlled trial of a sample of veterans with combat‐related PTSD, we examined the associations among pre‐, peri‐, and postdeployment adversity, social support, and clinician‐diagnosed comorbid MDD. Participants completed the Deployment Risk and Resilience Inventory and the Beck Depression Inventory–II as well as structured clinical interviews for diagnostic status. Among 223 U.S. veterans of the military operations in Iraq and Afghanistan (86.9% male) with primary combat‐related PTSD, 69.5% had current comorbid MDD. After adjustment for sex, a linear regression model indicated that more concerns about family disruptions during deployment, f2 = 0.065; more harassment during deployment, f2 = 0.020; and lower ratings of postdeployment social support, f2 = 0.154, were associated with more severe self‐reported depression symptoms. Interventions that enhance social support as well as societal efforts to foster successful postdeployment reintegration are critical for reducing the mental health burden associated with this highly prevalent comorbidity in veterans with combat‐related PTSD.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/155948/1/jts22496_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/155948/2/jts22496.pd

    Restricted dispersal in a sea of gene flow

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    Howfar domarine larvae disperse in the ocean? Decades of population genetic studies have revealed generally low levels of genetic structure at large spatial scales (hundreds of kilometres). Yet this result, typically based on discrete sampling designs, does not necessarily imply extensive dispersal. Here, we adopt a continuous sampling strategy along 950 km of coast in the northwestern Mediterranean Sea to address this question in four species. In line with expectations, we observe weak genetic structure at a large spatial scale. Nevertheless, our continuous sampling strategy uncovers a pattern of isolation by distance at small spatial scales (few tens of kilometres) in two species. Individual- based simulations indicate that this signal is an expected signature of restricted dispersal. At the other extreme of the connectivity spectrum, two pairs of individuals that are closely related genetically were found more than 290 km apart, indicating long-distance dispersal. Such a combination of restricted dispersal with rare long-distance dispersal events is supported by a high-resolution biophysical model of larval dispersal in the study area, and we posit that it may be common in marine species. Our results bridge population genetic studies with direct dispersal studies and have implications for the design of marine reserve networksVersiĂłn del edito
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