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Tropical vegetation productivity and atmospheric methane over the last 40,000 years from model simulations and stalagmites in Sulawesi, Indonesia
- Claire E. Krause, Alena K. Kimbrough, Michael K. Gagan, Peter O. Hopcroft, Gavin B. Dunbar, Wahyoe S. Hantoro, John C. Hellstrom, Hai Cheng, R. Lawrence Edwards, Henri Wong, Bambang W. Suwargadi, Paul J. Valdes, Hamdi Rifai
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- Journal:
- Quaternary Research / Volume 118 / March 2024
- Published online by Cambridge University Press:
- 26 February 2024, pp. 126-141
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Recent research has shown the potential of speleothem δ13C to record a range of environmental processes. Here, we report on 230Th-dated stalagmite δ13C records for southwest Sulawesi, Indonesia, over the last 40,000 yr to investigate the relationship between tropical vegetation productivity and atmospheric methane concentrations. We demonstrate that the Sulawesi stalagmite δ13C record is driven by changes in vegetation productivity and soil respiration and explore the link between soil respiration and tropical methane emissions using HadCM3 and the Sheffield Dynamic Global Vegetation Model. The model indicates that changes in soil respiration are primarily driven by changes in temperature and CO2, in line with our interpretation of stalagmite δ13C. In turn, modelled methane emissions are driven by soil respiration, providing a mechanism that links methane to stalagmite δ13C. This relationship is particularly strong during the last glaciation, indicating a key role for the tropics in controlling atmospheric methane when emissions from high-latitude boreal wetlands were suppressed. With further investigation, the link between δ13C in stalagmites and tropical methane could provide a low-latitude proxy complementary to polar ice core records to improve our understanding of the glacial–interglacial methane budget.
Determinants of incomplete childhood hepatitis B vaccination in Sierra Leone, Liberia, and Guinea: Analysis of national surveys (2018–2020)
- George A. Yendewa, Peter B. James, Amir Mohareb, Umaru Barrie, Samuel P. E. Massaquoi, Sahr A. Yendewa, Manal Ghazzawi, Tahir Bockarie, Peterlyn E. Cummings, Ibrahima S. Diallo, Ambulai Johnson, Benjamin Vohnm, Lawrence S. Babawo, Gibrilla F. Deen, Mustapha Kabba, Foday Sahr, Sulaiman Lakoh, Robert A. Salata
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- Journal:
- Epidemiology & Infection / Volume 151 / 2023
- Published online by Cambridge University Press:
- 03 November 2023, e193
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Vaccination against hepatitis B virus (HBV) is effective at preventing vertical transmission. Sierra Leone, Liberia, and Guinea are hyperendemic West African countries; yet, childhood vaccination coverage is suboptimal, and the determinants of incomplete vaccination are poorly understood. We analyzed national survey data (2018–2020) of children aged 4–35 months to assess complete HBV vaccination (receiving 3 doses of the pentavalent vaccine) and incomplete vaccination (receiving <3 doses). Statistical analysis was conducted using the complex sample command in SPSS (version 28). Multivariate logistic regression was used to identify determinants of incomplete immunization. Overall, 11,181 mothers were analyzed (4,846 from Sierra Leone, 2,788 from Liberia, and 3,547 from Guinea). Sierra Leone had the highest HBV childhood vaccination coverage (70.3%), followed by Liberia (64.6%) and Guinea (39.3%). Within countries, HBV vaccination coverage varied by socioeconomic characteristics and healthcare access. In multivariate regression analysis, factors that were significantly associated with incomplete vaccination in at least one country included sex of the child, Muslim mothers, lower household wealth index, <4 antenatal visits, home delivery, and distance to health facility vaccination (all p < 0.05). Understanding and addressing modifiable determinants of incomplete vaccination will be essential to help achieve the 2030 viral hepatitis elimination goals.
An approach for collaborative development of a federated biomedical knowledge graph-based question-answering system: Question-of-the-Month challenges
- Karamarie Fecho, Chris Bizon, Tursynay Issabekova, Sierra Moxon, Anne E. Thessen, Shervin Abdollahi, Sergio E. Baranzini, Basazin Belhu, William E. Byrd, Lawrence Chung, Andrew Crouse, Marc P. Duby, Stephen Ferguson, Aleksandra Foksinska, Laura Forero, Jennifer Friedman, Vicki Gardner, Gwênlyn Glusman, Jennifer Hadlock, Kristina Hanspers, Eugene Hinderer, Charlotte Hobbs, Gregory Hyde, Sui Huang, David Koslicki, Philip Mease, Sandrine Muller, Christopher J. Mungall, Stephen A. Ramsey, Jared Roach, Irit Rubin, Shepherd H. Schurman, Anath Shalev, Brett Smith, Karthik Soman, Sarah Stemann, Andrew I. Su, Casey Ta, Paul B. Watkins, Mark D. Williams, Chunlei Wu, Colleen H. Xu, The Biomedical Data Translator Consortium
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- Journal:
- Journal of Clinical and Translational Science / Volume 7 / Issue 1 / 2023
- Published online by Cambridge University Press:
- 14 September 2023, e214
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Knowledge graphs have become a common approach for knowledge representation. Yet, the application of graph methodology is elusive due to the sheer number and complexity of knowledge sources. In addition, semantic incompatibilities hinder efforts to harmonize and integrate across these diverse sources. As part of The Biomedical Translator Consortium, we have developed a knowledge graph–based question-answering system designed to augment human reasoning and accelerate translational scientific discovery: the Translator system. We have applied the Translator system to answer biomedical questions in the context of a broad array of diseases and syndromes, including Fanconi anemia, primary ciliary dyskinesia, multiple sclerosis, and others. A variety of collaborative approaches have been used to research and develop the Translator system. One recent approach involved the establishment of a monthly “Question-of-the-Month (QotM) Challenge” series. Herein, we describe the structure of the QotM Challenge; the six challenges that have been conducted to date on drug-induced liver injury, cannabidiol toxicity, coronavirus infection, diabetes, psoriatic arthritis, and ATP1A3-related phenotypes; the scientific insights that have been gleaned during the challenges; and the technical issues that were identified over the course of the challenges and that can now be addressed to foster further development of the prototype Translator system. We close with a discussion on Large Language Models such as ChatGPT and highlight differences between those models and the Translator system.
P.017 Convergent and contrasting modulation of saccade and pupil responses by several neurodegenerative diseases during free viewing of video clips
- HC Riek, BJ White, DC Brien, BC Coe, J Huang, A Abrahao, SE Black, M Borrie, E Finger, CE Fischer, AR Frank, M Freedman, DA Grimes, M Jog, S Kumar, D Kwan, AE Lang, JM Lawrence-Dewar, C Marras, M Masellis, SH Pasternak, BG Pollock, TK Rajji, DP Seitz, C Shoesmith, TD Steeves, B Tan, DF Tang-Wai, C Tartaglia, J Turnbull, L Zinman, ONDRI Investigators DP Munoz
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- Journal:
- Canadian Journal of Neurological Sciences / Volume 50 / Issue s2 / June 2023
- Published online by Cambridge University Press:
- 05 June 2023, p. S62
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Background: Saccade and pupil responses are potential neurodegenerative disease biomarkers due to overlap between oculomotor circuitry and disease-affected areas. Instruction-based tasks have previously been examined as biomarker sources, but are arduous for patients with limited cognitive abilities; additionally, few studies have evaluated multiple neurodegenerative pathologies concurrently. Methods: The Ontario Neurodegenerative Disease Research Initiative recruited individuals with Alzheimer’s disease (AD), mild cognitive impairment (MCI), amyotrophic lateral sclerosis (ALS), frontotemporal dementia, progressive supranuclear palsy, or Parkinson’s disease (PD). Patients (n=274, age 40-86) and healthy controls (n=101, age 55-86) viewed 10 minutes of frequently changing video clips without instruction while their eyes were tracked. We evaluated differences in saccade and pupil parameters (e.g. saccade frequency and amplitude, pupil size, responses to clip changes) between groups. Results: Preliminary data indicates low-level behavioural alterations in multiple disease cohorts: increased centre bias, lower overall saccade rate and reduced saccade amplitude. After clip changes, patient groups generally demonstrated lower saccade rate but higher microsaccade rate following clip change to varying degrees. Additionally, pupil responses were blunted (AD, MCI, ALS) or exaggerated (PD). Conclusions: This task may generate behavioural biomarkers even in cognitively impaired populations. Future work should explore the possible effects of factors such as medication and disease stage.
Resistance of Palmer amaranth (Amaranthus palmeri) to S-metolachlor in the midsouthern United States
- Koffi Badou Jeremie Kouame, Matthew B. Bertucci, Mary C. Savin, Taghi Bararpour, Lawrence E. Steckel, Thomas R. Butts, Cammy D. Willett, Fellipe G. Machado, Nilda Roma-Burgos
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- Journal:
- Weed Science / Volume 70 / Issue 4 / July 2022
- Published online by Cambridge University Press:
- 14 July 2022, pp. 380-389
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Palmer amaranth (Amaranthus palmeri S. Watson) is one of the most problematic weeds in many cropping systems in the midsouthern United States because of its multiple weedy traits and its propensity to evolve resistance to many herbicides with different mechanisms of action. In Arkansas, A. palmeri has evolved metabolic resistance to S-metolachlor, compromising the effectiveness of an important weed management tool. Greenhouse studies were conducted to evaluate the differential response of A. palmeri accessions from three states (Arkansas, Mississippi, and Tennessee) to (1) assess the occurrence of resistance to S-metolachlor among A. palmeri populations, (2) evaluate the resistance level in selected accessions and their resistant progeny, (3) and determine the susceptibility of most resistant accessions to other soil-applied herbicides. Seeds were collected from 168 crop fields between 2017 and 2019. One hundred seeds per accession were planted in silt loam soil without herbicide for >20 yr and sprayed with the labeled rate of S-metolachlor (1,120 g ai ha−1). Six accessions (four from Arkansas and two from Mississippi) were classified resistant to S-metolachlor. The effective doses (LD50) to control the parent accessions ranged between 73 and 443 g ha−1, and those of F1 progeny of survivors were 73 to 577 g ha−1. The resistance level was generally greater among progeny of surviving plants than among resistant field populations. The resistant field populations required 2.2 to 7.0 times more S-metolachlor to reduce seedling emergence 50%, while the F1 of survivors needed up to 9.2 times more herbicide to reduce emergence 50% compared with the susceptible standard.
P.002 Saccade parameters reveal cognitive impairment and differentially associate with cognitive domains across neurodegenerative diseases
- HC Riek, BC Coe, DC Brien, J Huang, A Abrahao, S Arnott, D Beaton, M Binns, S Black, M Borrie, L Casaubon, D Dowlatshahi, E Finger, C Fischer, A Frank, M Freedman, D Grimes, A Hassan, M Jog, S Kumar, D Kwan, A Lang, J Lawrence Dewar, B Levine, W Lou, J Mandzia, C Marras, M Masellis, P McLaughlin, J Orange, S Pasternak, A Peltsch, B Pollock, T Rajji, A Roberts, D Sahlas, G Saposnik, D Seitz, C Shoesmith, T Steeves, S Strother, S Sujanthan, K Sunderland, R Swartz, B Tan, D Tang-Wai, C Tartaglia, A Troyer, J Turnbull, L Zinman, ONDRI Investigators (), DP Munoz
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- Journal:
- Canadian Journal of Neurological Sciences / Volume 49 / Issue s1 / June 2022
- Published online by Cambridge University Press:
- 24 June 2022, p. S8
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Background: Eye movements reveal neurodegenerative disease processes due to overlap between oculomotor circuitry and disease-affected areas. Characterizing oculomotor behaviour in context of cognitive function may enhance disease diagnosis and monitoring. We therefore aimed to quantify cognitive impairment in neurodegenerative disease using saccade behaviour and neuropsychology. Methods: The Ontario Neurodegenerative Disease Research Initiative recruited individuals with neurodegenerative disease: one of Alzheimer’s disease, mild cognitive impairment, amyotrophic lateral sclerosis, frontotemporal dementia, Parkinson’s disease, or cerebrovascular disease. Patients (n=450, age 40-87) and healthy controls (n=149, age 42-87) completed a randomly interleaved pro- and anti-saccade task (IPAST) while their eyes were tracked. We explored the relationships of saccade parameters (e.g. task errors, reaction times) to one another and to cognitive domain-specific neuropsychological test scores (e.g. executive function, memory). Results: Task performance worsened with cognitive impairment across multiple diseases. Subsets of saccade parameters were interrelated and also differentially related to neuropsychology-based cognitive domain scores (e.g. antisaccade errors and reaction time associated with executive function). Conclusions: IPAST detects global cognitive impairment across neurodegenerative diseases. Subsets of parameters associate with one another, suggesting disparate underlying circuitry, and with different cognitive domains. This may have implications for use of IPAST as a cognitive screening tool in neurodegenerative disease.
Early Science from POSSUM: Shocks, turbulence, and a massive new reservoir of ionised gas in the Fornax cluster
- Part of
- C. S. Anderson, G. H. Heald, J. A. Eilek, E. Lenc, B. M. Gaensler, Lawrence Rudnick, C. L. Van Eck, S. P. O’Sullivan, J. M. Stil, A. Chippendale, C. J. Riseley, E. Carretti, J. West, J. Farnes, L. Harvey-Smith, N. M. McClure-Griffiths, Douglas C. J. Bock, J. D. Bunton, B. Koribalski, C. D. Tremblay, M. A. Voronkov, K. Warhurst
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- Publications of the Astronomical Society of Australia / Volume 38 / 2021
- Published online by Cambridge University Press:
- 23 April 2021, e020
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We present the first Faraday rotation measure (RM) grid study of an individual low-mass cluster—the Fornax cluster—which is presently undergoing a series of mergers. Exploiting commissioning data for the POlarisation Sky Survey of the Universe’s Magnetism (POSSUM) covering a ${\sim}34$ square degree sky area using the Australian Square Kilometre Array Pathfinder (ASKAP), we achieve an RM grid density of ${\sim}25$ RMs per square degree from a 280-MHz band centred at 887 MHz, which is similar to expectations for forthcoming GHz-frequency ${\sim}3\pi$-steradian sky surveys. These data allow us to probe the extended magnetoionic structure of the cluster and its surroundings in unprecedented detail. We find that the scatter in the Faraday RM of confirmed background sources is increased by $16.8\pm2.4$ rad m−2 within 1$^\circ$ (360 kpc) projected distance to the cluster centre, which is 2–4 times larger than the spatial extent of the presently detectable X-ray-emitting intracluster medium (ICM). The mass of the Faraday-active plasma is larger than that of the X-ray-emitting ICM and exists in a density regime that broadly matches expectations for moderately dense components of the Warm-Hot Intergalactic Medium. We argue that forthcoming RM grids from both targeted and survey observations may be a singular probe of cosmic plasma in this regime. The morphology of the global Faraday depth enhancement is not uniform and isotropic but rather exhibits the classic morphology of an astrophysical bow shock on the southwest side of the main Fornax cluster, and an extended, swept-back wake on the northeastern side. Our favoured explanation for these phenomena is an ongoing merger between the main cluster and a subcluster to the southwest. The shock’s Mach angle and stand-off distance lead to a self-consistent transonic merger speed with Mach 1.06. The region hosting the Faraday depth enhancement also appears to show a decrement in both total and polarised radio emission compared to the broader field. We evaluate cosmic variance and free-free absorption by a pervasive cold dense gas surrounding NGC 1399 as possible causes but find both explanations unsatisfactory, warranting further observations. Generally, our study illustrates the scientific returns that can be expected from all-sky grids of discrete sources generated by forthcoming all-sky radio surveys.
2177 – Neuroanatomical Changes Associated With Subthreshold Depression In Adolescents
- H. Vulser, M.-L. Paillere-Martinot, H. Lemaitre, R. Miranda, E. Artiges, R. Goodman, J. Penttilä, M. Struve, T. Fadai, V. Kappel, L. Poustka, P. Conrod, T. Banaschewski, A. Barbot, G.J. Barker, C. Büchel, H. Flor, J. Gallinat, H. Garavan, A. Heinz, B. Ittermann, C. Lawrence, E. Loth, K. Mann, T. Paus, Z. Pausova, M. Rietschel, T.W. Robbins, M. Smolka, G. Schumann, J.-L. Martinot, IMAGEN Consortium
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- European Psychiatry / Volume 28 / Issue S1 / 2013
- Published online by Cambridge University Press:
- 15 April 2020, 28-E1340
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Introduction
Although neuroimaging studies suggest brain regional abnormalities in depressive disorders, it remains unclear whether abnormalities are present at illness onset or reflect disease progression.
ObjectivesWe hypothesized that cerebral variations were present in adolescents with subthreshold depression known to be at high risk for later full-blown depression.
AimsWe examined brain structural and diffusion-weighted magnetic resonance images of adolescents with subthreshold depression.
MethodsThe participants were extracted from the European IMAGEN study cohort of healthy adolescents recruited at age 14. Subthreshold depression was defined as a distinct period of abnormally depressed or irritable mood, or loss of interest, plus two or more depressive symptoms but without diagnosis of Major Depressive Episode. Comparisons were performed between adolescents meeting these criteria and control adolescents within the T1-weighted imaging modality (118 and 475 adolescents respectively) using voxel-based morphometry and the diffusion tensor imaging modality (89 ad 422 adolescents respectively) using tract-based spatial statistics. Whole brain analyses were performed with a statistical threshold set to p< 0.05 corrected for multiple comparisons.
ResultsCompared with controls, adolescents with subthreshold depression had smaller gray matter volume in caudate nuclei, medial frontal and cingulate cortices; smaller white matter volume in anterior limb of internal capsules, left forceps minor and right cingulum; and lower fractional anisotropy and higher radial diffusivity in the genu of corpus callosum.
ConclusionsThe findings suggest that adolescents with subthreshold depression have volumetric and microstructural gray and white matter changes in the emotion regulation frontal-striatal-limbic network.
Evaluation of the time-of-day effect of herbicides applied POST on protoporphyrinogen IX oxidase–resistant and –susceptible Palmer amaranth (Amaranthus palmeri)
- J. Drake Copeland, Garret B. Montgomery, Lawrence E. Steckel
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- Journal:
- Weed Technology / Volume 33 / Issue 5 / October 2019
- Published online by Cambridge University Press:
- 22 July 2019, pp. 651-657
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Studies to evaluate the effect of application time of day (TOD) and protoporphyrinogen IX oxidase (PPO)-inhibiting herbicide–resistant Palmer amaranth on the efficacy of commonly used herbicides was conducted in Tennessee in 2017 and 2018. Treatments of fomesafen, lactofen, acifluorfen, paraquat, glufosinate, glufosinate plus fomesafen, paraquat plus fomesafen, and paraquat plus metribuzin were applied to PPO-resistant (PPO-R) and PPO-susceptible (PPO-S) Palmer amaranth at sunrise and midday. Control of Palmer amaranth with acifluorfen, glufosinate, and glufosinate plus fomesafen was greater with the midday application. However, control of Palmer amaranth with paraquat-based treatments was greater with the sunrise application. TOD effects on PPO-inhibiting herbicides and paraquat-based treatments were more prominent for the PPO-R Palmer amaranth biotype. The TOD effect observed when applying glufosinate in early morning hours on PPO-S Palmer amaranth can be minimized by adding fomesafen to the tank mix. However, this strategy did not provide consistent performance on PPO-R Palmer amaranth. The percentages of living Palmer amaranth plants and control were greater when paraquat plus metribuzin was applied to both biotypes. These results highlight the necessity of at least two effective herbicide sites of action for POST applications intended for controlling PPO-R Palmer amaranth. In addition, the timing of herbicide applications can affect their activity in both PPO-R and PPO-S Palmer amaranth populations.
Evaluation of cover crop sensitivity to residual herbicides applied in the previous soybean [Glycine max (L.) Merr] crop
- Derek M. Whalen, Mandy D. Bish, Bryan G. Young, Aaron G. Hager, Shawn P. Conley, Daniel B. Reynolds, Lawrence E. Steckel, Jason K. Norsworthy, Kevin W. Bradley
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- Journal:
- Weed Technology / Volume 33 / Issue 2 / April 2019
- Published online by Cambridge University Press:
- 16 April 2019, pp. 312-320
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In recent years, the use of cover crops has increased in U.S. crop production systems. An important aspect of successful cover crop establishment is the preceding crop and herbicide program, because some herbicides have the potential to persist in the soil for several months. Few studies have been conducted to evaluate the sensitivity of cover crops to common residual herbicides used in soybean production. The same field experiment was conducted in 2016 in Arkansas, Illinois, Indiana, Missouri, Tennessee, and Wisconsin, and repeated in Arkansas, Illinois, Indiana, Mississippi, and Missouri in 2017 to evaluate the potential of residual soybean herbicides to carryover and reduce cover crop establishment. Herbicides applied during the soybean growing season included acetochlor; acetochlor plus fomesafen; chlorimuron plus thifensulfuron; fomesafen; fomesafen plus S-metolachlor followed by acetochlor; imazethapyr; pyroxasulfone; S-metolachlor; S-metolachlor plus fomesafen; sulfentrazone plus S-metolachlor; sulfentrazone plus S-metolachlor followed by fomesafen plus S-metolachlor; and sulfentrazone plus S-metolachlor followed by fomesafen plus S-metolachlor followed by acetochlor. Across all herbicide treatments, the sensitivity of cover crops to herbicide residues in the fall, from greatest to least, was forage radish = turnip > annual ryegrass = winter oat = triticale > cereal rye = Austrian winter pea = hairy vetch = wheat > crimson clover. Fomesafen (applied 21 and 42 days after planting [(DAP]); chlorimuron plus thifensulfuron and pyroxasulfone applied 42 DAP; sulfentrazone plus S-metolachlor followed by fomesafen plus S-metolachlor; and sulfentrazone plus S-metolachlor followed by fomesafen plus S-metolachlor followed by acetochlor caused the highest visual ground cover reduction to cover crop species at the fall rating. Study results indicate cover crops are most at risk when following herbicide applications in soybean containing certain active ingredients such as fomesafen, but overall there is a fairly low risk of cover crop injury from residual soybean herbicides applied in the previous soybean crop.
Distribution of PPX2 Mutations Conferring PPO-Inhibitor Resistance in Palmer Amaranth Populations of Tennessee
- J. Drake Copeland, Darci A. Giacomini, Patrick J. Tranel, Garret B. Montgomery, Lawrence E. Steckel
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- Weed Technology / Volume 32 / Issue 5 / October 2018
- Published online by Cambridge University Press:
- 09 November 2018, pp. 592-596
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Protoporphyrinogen IX oxidase (PPO)–inhibiting herbicides (WSSA Group 14) have been used in agronomic row crops for over 50 yr. Broadleaf weeds, including glyphosate-resistant Palmer amaranth, have been controlled by this herbicide site of action PRE and POST. Recently, Palmer amaranth populations were reported resistant to PPO inhibitors in 2011 in Arkansas, in 2015 in Tennessee, and in 2016 in Illinois. Historically, the mechanism for this resistance involves the deletion of a glycine at position 210 (ΔG210) in a PPO enzyme encoded by the PPX2 gene; however, the ΔG210 deletion did not explain all PPO inhibitor–resistant Palmer amaranth in Tennessee populations. Recently, two new mutations within PPX2 (R128G, R128M) that confer resistance to PPO inhibitors were identified in Palmer amaranth. Therefore, research is needed to document the presence and distribution of the three known mutations that confer PPO inhibitor resistance in Tennessee. In 2017, a survey was conducted in 18 fields with Palmer amaranth to determine whether resistance existed and the prevalence of each known mutation in each field. Fomesafen was applied at 265 g ai ha–1 to Palmer amaranth infestations within each field to select for resistant weeds for later analysis. Where resistance was described (70% of surviving plants), the ΔG210 mutation was detected in 47% of resistant plants. The R128G mutation accounted for 42% of resistance, similar to the frequency of the ΔG210 mutation. The R128M mutation was less frequent than the other two mutations, accounting for only 10% of the resistance. All mutations detected in this study were heterozygous. Additionally, no more than one of the three PPX2 mutations were detected in an individual surviving plant. Similar to previous research, about 70% of PPO resistance was accounted for by these three known mutations, leaving about 30% of resistance not characterized in Tennessee populations. Survivors not showing the three known PPO mutations suggest that other resistance mechanisms are present.
Instruments and methods: a case study of ice core bubbles as strain indicators
- John M. Fegyveresi, Richard B. Alley, Donald E. Voigt, Joan J. Fitzpatrick, Lawrence A. Wilen
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- Annals of Glaciology / Volume 60 / Issue 78 / April 2019
- Published online by Cambridge University Press:
- 16 October 2018, pp. 8-19
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Measurements of a sample from ~580 m depth in the WAIS Divide (WDC06A) ice core reveal that bubbles are preferentially elongated in the basal plane of their parent grain, as expected if bubble shape preserves the record of dominant basal glide. This suggests that a method using bubbles as strain gauges could provide insights to grain-scale ice deformation. We introduce a technique using fabric and image analyses of paired thin and thick sections. Comparison of the crystallographic orientations of 148 grains and the shape orientations of 2377 intragrain bubbles reveals a strongly preferred elongation of bubbles in the grain basal planes (R2 = 0.96). Elongation magnitudes are consistent with a balance between ice flow deformation and diffusive restoration, with larger bubbles more elongated. Assuming bubbles record ice strain, grains with greater resolved stress on their basal planes from the far-field ice flow stresses show greater deformation, but with large variability suggesting that heterogeneity of the local stress field causes deformation even in unfavorably oriented grains. A correlation is also observed among bubble elongation, grain size, and bubble size, explaining a small but significant fraction of the variance ( P< 0.05), with implications for controls on ice deformation, as discussed here.
Glyphosate-Resistant Junglerice (Echinochloa colona) from Mississippi and Tennessee: Magnitude and Resistance Mechanisms
- Vijay K. Nandula, Garret B. Montgomery, Amaranatha R. Vennapusa, Mithila Jugulam, Darci A. Giacomini, Jeffery D. Ray, Jason A. Bond, Lawrence E. Steckel, Patrick J. Tranel
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- Weed Science / Volume 66 / Issue 5 / September 2018
- Published online by Cambridge University Press:
- 11 September 2018, pp. 603-610
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Recently, several incidents of glyphosate failure on junglerice [Echinochloa colona (L.) Link] have been reported in the midsouthern United States, specifically in Mississippi and Tennessee. Research was conducted to measure the magnitude of glyphosate resistance and to determine the mechanism(s) of resistance to glyphosate in E. colona populations from Mississippi and Tennessee. ED50 (dose required to reduce plant growth by 50%) values for a resistant MSGR4 biotype, a resistant TNGR population, and a known susceptible MSGS population were 0.8, 1.62, and 0.23 kg ae ha−1 of glyphosate, respectively. The resistance index calculated from the these ED50 values indicated that the MSGR4 biotype and TNGR population were 4- and 7-fold, respectively, resistant to glyphosate relative to the MSGS population. The absorption patterns of [14C]glyphosate in the TNGR and MSGS populations were similar. However, the MSGS population translocated 13% more [14C]glyphosate out of the treated leaf compared with the TNGR population at 48 h after treatment. EPSPS gene sequence analyses of TNGR E. colona indicated no evidence of any point mutations, but several resistant biotypes, including MSGR4, possessed a single-nucleotide substitution of T for C at codon 106 position, resulting in a proline-to-serine substitution (CCA to TCA). Results from quantitative polymerase chain reaction analyses suggested that there was no amplification of the EPSPS gene in the resistant populations and biotypes. Thus, the mechanism of resistance in the MSGR population (and associated biotypes) is, in part, due to a target-site mutation at the 106 loci of the EPSPS gene, while reduced translocation of glyphosate was found to confer glyphosate resistance in the TNGR population.
Dicamba-Tolerant Soybean Combined Cover Crop to Control Palmer amaranth – CORRIGENDUM
- Garret B. Montgomery, Angela T. McClure, Robert M. Hayes, Forbes R. Walker, Scott A. Senseman, Lawrence E. Steckel
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- Weed Technology / Volume 32 / Issue 3 / June 2018
- Published online by Cambridge University Press:
- 13 February 2018, p. 352
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Dicamba-Tolerant Soybean Combined Cover Crop to Control Palmer amaranth
- Garret B. Montgomery, Angela T. McClure, Robert M. Hayes, Forbes R. Walker, Scott A. Senseman, Lawrence E. Steckel
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- Weed Technology / Volume 32 / Issue 2 / April 2018
- Published online by Cambridge University Press:
- 20 November 2017, pp. 109-115
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A study was conducted to evaluate the response of glyphosate- and dicamba-tolerant (GDT) soybean and weed control from cover crop different termination intervals before and after soybean planting. Cover crop biomass was highest when terminated at planting, decreased with the 7- and 14-d preplant (DPP) and day-after-planting (DAP) timings, and again at the 14 DPP and DAP timings. Glyphosate+dicamba provided total control of cover crops by 21 DAP. Cover crop termination timing did not influence soybean population or yield. Palmer amaranth control at the 21 and 28 d after termination (DAT) was 97% to 99%. Differences in Palmer amaranth control were not detected among herbicide programs or termination intervals at the end of season rating, and all treatments provided ≥97% control. Although differences in Palmer amaranth control were not apparent at the end of the season, the delay in cover crop affected the number of days until 10-cm Palmer amaranth was present. When utilizing a wheat+hairy vetch cover crop in DGT soybeans, producers should delay cover crop termination until 11 to 14 DPP and make at least one POST application of glyphosate+dicamba+an additional herbicide mode of action (MOA) to maximize Palmer amaranth control and soybean yields.
Effect of Time of Day of Application of 2,4-D, Dicamba, Glufosinate, Paraquat, and Saflufenacil on Horseweed (Conyza canadensis) Control
- Garret B. Montgomery, Joyce A. Treadway, Julie L. Reeves, Lawrence E. Steckel
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- Weed Technology / Volume 31 / Issue 4 / August 2017
- Published online by Cambridge University Press:
- 24 August 2017, pp. 550-556
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A study to evaluate the effect of application time of day (TOD) on the efficacy of five burndown herbicides was conducted in Alabama and Tennessee. Treatments of 2,4-D, dicamba, glufosinate, paraquat, and saflufenacil were applied at sunrise, midday, or sunset to a native population of horseweed and analyzed separately. Control of glyphosate-resistant (GR) horseweed with 2,4-D, dicamba, glufosinate, and saflufenacil was greatest from the midday application. Percentage of living horseweed counts for all of these herbicides followed a similar pattern. Control from paraquat was lowest at the midday timing and greatest from the sunset application with surviving horseweed plant populations reflecting those control ratings. Application TOD significantly affected all of the herbicides in this research. Applications of 2,4-D, dicamba, glufosinate, and saflufenacil are more efficacious when applied during the middle portion of the day, while paraquat is more efficacious when applied at sunset for maximum horseweed control.
Physical properties of the WAIS Divide ice core
- Joan J. Fitzpatrick, Donald E. Voigt, John M. Fegyveresi, Nathan T. Stevens, Matthew K. Spencer, Jihong Cole-Dai, Richard B. Alley, Gabriella E. Jardine, Eric D. Cravens, Lawrence A. Wilen, T.J. Fudge, Joseph R. Mcconnell
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- Journal:
- Journal of Glaciology / Volume 60 / Issue 224 / 2014
- Published online by Cambridge University Press:
- 10 July 2017, pp. 1181-1198
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The WAIS (West Antarctic Ice Sheet) Divide deep ice core was recently completed to a total depth of 3405 m, ending 50 m above the bed. Investigation of the visual stratigraphy and grain characteristics indicates that the ice column at the drilling location is undisturbed by any large-scale overturning or discontinuity. The climate record developed from this core is therefore likely to be continuous and robust. Measured grain-growth rates, recrystallization characteristics, and grain-size response at climate transitions fit within current understanding. Significant impurity control on grain size is indicated from correlation analysis between impurity loading and grain size. Bubble-number densities and bubble sizes and shapes are presented through the full extent of the bubbly ice. Where bubble elongation is observed, the direction of elongation is preferentially parallel to the trace of the basal (0001) plane. Preferred crystallographic orientation of grains is present in the shallowest samples measured, and increases with depth, progressing to a vertical-girdle pattern that tightens to a vertical single-maximum fabric. This single-maximum fabric switches into multiple maxima as the grain size increases rapidly in the deepest, warmest ice. A strong dependence of the fabric on the impurity-mediated grain size is apparent in the deepest samples.
Why are most EU pigs tail docked? Economic and ethical analysis of four pig housing and management scenarios in the light of EU legislation and animal welfare outcomes
- R. B. D’Eath, J. K. Niemi, B. Vosough Ahmadi, K. M. D. Rutherford, S. H. Ison, S. P. Turner, H. T. Anker, T. Jensen, M. E. Busch, K. K. Jensen, A. B. Lawrence, P. Sandøe
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To limit tail biting incidence, most pig producers in Europe tail dock their piglets. This is despite EU Council Directive 2008/120/EC banning routine tail docking and allowing it only as a last resort. The paper aims to understand what it takes to fulfil the intentions of the Directive by examining economic results of four management and housing scenarios, and by discussing their consequences for animal welfare in the light of legal and ethical considerations. The four scenarios compared are: ‘Standard Docked’, a conventional housing scenario with tail docking meeting the recommendations for Danish production (0.7 m2/pig); ‘Standard Undocked’, which is the same as ‘Standard Docked’ but with no tail docking, ‘Efficient Undocked’ and ‘Enhanced Undocked’, which have increased solid floor area (0.9 and 1.0 m2/pig, respectively) provision of loose manipulable materials (100 and 200 g/straw per pig per day) and no tail docking. A decision tree model based on data from Danish and Finnish pig production suggests that Standard Docked provides the highest economic gross margin with the least tail biting. Given our assumptions, Enhanced Undocked is the least economic, although Efficient Undocked is better economically and both result in a lower incidence of tail biting than Standard Undocked but higher than Standard Docked. For a pig, being bitten is worse for welfare (repeated pain, risk of infections) than being docked, but to compare welfare consequences at a farm level means considering the number of affected pigs. Because of the high levels of biting in Standard Undocked, it has on average inferior welfare to Standard Docked, whereas the comparison of Standard Docked and Enhanced (or Efficient) Undocked is more difficult. In Enhanced (or Efficient) Undocked, more pigs than in Standard Docked suffer from being tail bitten, whereas all the pigs avoid the acute pain of docking endured by the pigs in Standard Docked. We illustrate and discuss this ethical balance using numbers derived from the above-mentioned data. We discuss our results in the light of the EU Directive and its adoption and enforcement by Member States. Widespread use of tail docking seems to be accepted, mainly because the alternative steps that producers are required to take before resorting to it are not specified in detail. By tail docking, producers are acting in their own best interests. We suggest that for the practice of tail docking to be terminated in a way that benefits animal welfare, changes in the way pigs are housed and managed may first be required.
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- By Mitchell Aboulafia, Frederick Adams, Marilyn McCord Adams, Robert M. Adams, Laird Addis, James W. Allard, David Allison, William P. Alston, Karl Ameriks, C. Anthony Anderson, David Leech Anderson, Lanier Anderson, Roger Ariew, David Armstrong, Denis G. Arnold, E. J. Ashworth, Margaret Atherton, Robin Attfield, Bruce Aune, Edward Wilson Averill, Jody Azzouni, Kent Bach, Andrew Bailey, Lynne Rudder Baker, Thomas R. Baldwin, Jon Barwise, George Bealer, William Bechtel, Lawrence C. Becker, Mark A. Bedau, Ernst Behler, José A. Benardete, Ermanno Bencivenga, Jan Berg, Michael Bergmann, Robert L. Bernasconi, Sven Bernecker, Bernard Berofsky, Rod Bertolet, Charles J. Beyer, Christian Beyer, Joseph Bien, Joseph Bien, Peg Birmingham, Ivan Boh, James Bohman, Daniel Bonevac, Laurence BonJour, William J. Bouwsma, Raymond D. Bradley, Myles Brand, Richard B. Brandt, Michael E. Bratman, Stephen E. Braude, Daniel Breazeale, Angela Breitenbach, Jason Bridges, David O. Brink, Gordon G. Brittan, Justin Broackes, Dan W. Brock, Aaron Bronfman, Jeffrey E. Brower, Bartosz Brozek, Anthony Brueckner, Jeffrey Bub, Lara Buchak, Otavio Bueno, Ann E. Bumpus, Robert W. Burch, John Burgess, Arthur W. Burks, Panayot Butchvarov, Robert E. Butts, Marina Bykova, Patrick Byrne, David Carr, Noël Carroll, Edward S. Casey, Victor Caston, Victor Caston, Albert Casullo, Robert L. Causey, Alan K. L. Chan, Ruth Chang, Deen K. Chatterjee, Andrew Chignell, Roderick M. Chisholm, Kelly J. Clark, E. J. Coffman, Robin Collins, Brian P. Copenhaver, John Corcoran, John Cottingham, Roger Crisp, Frederick J. Crosson, Antonio S. Cua, Phillip D. Cummins, Martin Curd, Adam Cureton, Andrew Cutrofello, Stephen Darwall, Paul Sheldon Davies, Wayne A. Davis, Timothy Joseph Day, Claudio de Almeida, Mario De Caro, Mario De Caro, John Deigh, C. F. Delaney, Daniel C. Dennett, Michael R. DePaul, Michael Detlefsen, Daniel Trent Devereux, Philip E. Devine, John M. Dillon, Martin C. Dillon, Robert DiSalle, Mary Domski, Alan Donagan, Paul Draper, Fred Dretske, Mircea Dumitru, Wilhelm Dupré, Gerald Dworkin, John Earman, Ellery Eells, Catherine Z. Elgin, Berent Enç, Ronald P. Endicott, Edward Erwin, John Etchemendy, C. Stephen Evans, Susan L. Feagin, Solomon Feferman, Richard Feldman, Arthur Fine, Maurice A. Finocchiaro, William FitzPatrick, Richard E. Flathman, Gvozden Flego, Richard Foley, Graeme Forbes, Rainer Forst, Malcolm R. Forster, Daniel Fouke, Patrick Francken, Samuel Freeman, Elizabeth Fricker, Miranda Fricker, Michael Friedman, Michael Fuerstein, Richard A. Fumerton, Alan Gabbey, Pieranna Garavaso, Daniel Garber, Jorge L. A. Garcia, Robert K. Garcia, Don Garrett, Philip Gasper, Gerald Gaus, Berys Gaut, Bernard Gert, Roger F. Gibson, Cody Gilmore, Carl Ginet, Alan H. Goldman, Alvin I. Goldman, Alfonso Gömez-Lobo, Lenn E. Goodman, Robert M. Gordon, Stefan Gosepath, Jorge J. E. Gracia, Daniel W. Graham, George A. Graham, Peter J. Graham, Richard E. Grandy, I. Grattan-Guinness, John Greco, Philip T. Grier, Nicholas Griffin, Nicholas Griffin, David A. Griffiths, Paul J. Griffiths, Stephen R. Grimm, Charles L. Griswold, Charles B. Guignon, Pete A. Y. Gunter, Dimitri Gutas, Gary Gutting, Paul Guyer, Kwame Gyekye, Oscar A. Haac, Raul Hakli, Raul Hakli, Michael Hallett, Edward C. Halper, Jean Hampton, R. James Hankinson, K. R. Hanley, Russell Hardin, Robert M. Harnish, William Harper, David Harrah, Kevin Hart, Ali Hasan, William Hasker, John Haugeland, Roger Hausheer, William Heald, Peter Heath, Richard Heck, John F. Heil, Vincent F. Hendricks, Stephen Hetherington, Francis Heylighen, Kathleen Marie Higgins, Risto Hilpinen, Harold T. Hodes, Joshua Hoffman, Alan Holland, Robert L. Holmes, Richard Holton, Brad W. Hooker, Terence E. Horgan, Tamara Horowitz, Paul Horwich, Vittorio Hösle, Paul Hoβfeld, Daniel Howard-Snyder, Frances Howard-Snyder, Anne Hudson, Deal W. Hudson, Carl A. Huffman, David L. Hull, Patricia Huntington, Thomas Hurka, Paul Hurley, Rosalind Hursthouse, Guillermo Hurtado, Ronald E. Hustwit, Sarah Hutton, Jonathan Jenkins Ichikawa, Harry A. Ide, David Ingram, Philip J. Ivanhoe, Alfred L. Ivry, Frank Jackson, Dale Jacquette, Joseph Jedwab, Richard Jeffrey, David Alan Johnson, Edward Johnson, Mark D. Jordan, Richard Joyce, Hwa Yol Jung, Robert Hillary Kane, Tomis Kapitan, Jacquelyn Ann K. Kegley, James A. Keller, Ralph Kennedy, Sergei Khoruzhii, Jaegwon Kim, Yersu Kim, Nathan L. King, Patricia Kitcher, Peter D. Klein, E. D. Klemke, Virginia Klenk, George L. Kline, Christian Klotz, Simo Knuuttila, Joseph J. Kockelmans, Konstantin Kolenda, Sebastian Tomasz Kołodziejczyk, Isaac Kramnick, Richard Kraut, Fred Kroon, Manfred Kuehn, Steven T. Kuhn, Henry E. Kyburg, John Lachs, Jennifer Lackey, Stephen E. Lahey, Andrea Lavazza, Thomas H. Leahey, Joo Heung Lee, Keith Lehrer, Dorothy Leland, Noah M. Lemos, Ernest LePore, Sarah-Jane Leslie, Isaac Levi, Andrew Levine, Alan E. Lewis, Daniel E. Little, Shu-hsien Liu, Shu-hsien Liu, Alan K. L. Chan, Brian Loar, Lawrence B. Lombard, John Longeway, Dominic McIver Lopes, Michael J. Loux, E. J. Lowe, Steven Luper, Eugene C. Luschei, William G. Lycan, David Lyons, David Macarthur, Danielle Macbeth, Scott MacDonald, Jacob L. Mackey, Louis H. Mackey, Penelope Mackie, Edward H. Madden, Penelope Maddy, G. B. Madison, Bernd Magnus, Pekka Mäkelä, Rudolf A. Makkreel, David Manley, William E. Mann (W.E.M.), Vladimir Marchenkov, Peter Markie, Jean-Pierre Marquis, Ausonio Marras, Mike W. Martin, A. P. Martinich, William L. McBride, David McCabe, Storrs McCall, Hugh J. McCann, Robert N. McCauley, John J. McDermott, Sarah McGrath, Ralph McInerny, Daniel J. McKaughan, Thomas McKay, Michael McKinsey, Brian P. McLaughlin, Ernan McMullin, Anthonie Meijers, Jack W. Meiland, William Jason Melanson, Alfred R. Mele, Joseph R. Mendola, Christopher Menzel, Michael J. Meyer, Christian B. Miller, David W. Miller, Peter Millican, Robert N. Minor, Phillip Mitsis, James A. Montmarquet, Michael S. Moore, Tim Moore, Benjamin Morison, Donald R. Morrison, Stephen J. Morse, Paul K. Moser, Alexander P. D. Mourelatos, Ian Mueller, James Bernard Murphy, Mark C. Murphy, Steven Nadler, Jan Narveson, Alan Nelson, Jerome Neu, Samuel Newlands, Kai Nielsen, Ilkka Niiniluoto, Carlos G. Noreña, Calvin G. Normore, David Fate Norton, Nikolaj Nottelmann, Donald Nute, David S. Oderberg, Steve Odin, Michael O’Rourke, Willard G. Oxtoby, Heinz Paetzold, George S. Pappas, Anthony J. Parel, Lydia Patton, R. P. Peerenboom, Francis Jeffry Pelletier, Adriaan T. Peperzak, Derk Pereboom, Jaroslav Peregrin, Glen Pettigrove, Philip Pettit, Edmund L. Pincoffs, Andrew Pinsent, Robert B. Pippin, Alvin Plantinga, Louis P. Pojman, Richard H. Popkin, John F. Post, Carl J. Posy, William J. Prior, Richard Purtill, Michael Quante, Philip L. Quinn, Philip L. Quinn, Elizabeth S. Radcliffe, Diana Raffman, Gerard Raulet, Stephen L. Read, Andrews Reath, Andrew Reisner, Nicholas Rescher, Henry S. Richardson, Robert C. Richardson, Thomas Ricketts, Wayne D. Riggs, Mark Roberts, Robert C. Roberts, Luke Robinson, Alexander Rosenberg, Gary Rosenkranz, Bernice Glatzer Rosenthal, Adina L. Roskies, William L. Rowe, T. M. Rudavsky, Michael Ruse, Bruce Russell, Lilly-Marlene Russow, Dan Ryder, R. M. Sainsbury, Joseph Salerno, Nathan Salmon, Wesley C. Salmon, Constantine Sandis, David H. Sanford, Marco Santambrogio, David Sapire, Ruth A. Saunders, Geoffrey Sayre-McCord, Charles Sayward, James P. Scanlan, Richard Schacht, Tamar Schapiro, Frederick F. Schmitt, Jerome B. Schneewind, Calvin O. Schrag, Alan D. Schrift, George F. Schumm, Jean-Loup Seban, David N. Sedley, Kenneth Seeskin, Krister Segerberg, Charlene Haddock Seigfried, Dennis M. Senchuk, James F. Sennett, William Lad Sessions, Stewart Shapiro, Tommie Shelby, Donald W. Sherburne, Christopher Shields, Roger A. Shiner, Sydney Shoemaker, Robert K. Shope, Kwong-loi Shun, Wilfried Sieg, A. John Simmons, Robert L. Simon, Marcus G. Singer, Georgette Sinkler, Walter Sinnott-Armstrong, Matti T. Sintonen, Lawrence Sklar, Brian Skyrms, Robert C. Sleigh, Michael Anthony Slote, Hans Sluga, Barry Smith, Michael Smith, Robin Smith, Robert Sokolowski, Robert C. Solomon, Marta Soniewicka, Philip Soper, Ernest Sosa, Nicholas Southwood, Paul Vincent Spade, T. L. S. Sprigge, Eric O. Springsted, George J. Stack, Rebecca Stangl, Jason Stanley, Florian Steinberger, Sören Stenlund, Christopher Stephens, James P. Sterba, Josef Stern, Matthias Steup, M. A. Stewart, Leopold Stubenberg, Edith Dudley Sulla, Frederick Suppe, Jere Paul Surber, David George Sussman, Sigrún Svavarsdóttir, Zeno G. Swijtink, Richard Swinburne, Charles C. Taliaferro, Robert B. Talisse, John Tasioulas, Paul Teller, Larry S. Temkin, Mark Textor, H. S. Thayer, Peter Thielke, Alan Thomas, Amie L. Thomasson, Katherine Thomson-Jones, Joshua C. Thurow, Vzalerie Tiberius, Terrence N. Tice, Paul Tidman, Mark C. Timmons, William Tolhurst, James E. Tomberlin, Rosemarie Tong, Lawrence Torcello, Kelly Trogdon, J. D. Trout, Robert E. Tully, Raimo Tuomela, John Turri, Martin M. Tweedale, Thomas Uebel, Jennifer Uleman, James Van Cleve, Harry van der Linden, Peter van Inwagen, Bryan W. Van Norden, René van Woudenberg, Donald Phillip Verene, Samantha Vice, Thomas Vinci, Donald Wayne Viney, Barbara Von Eckardt, Peter B. M. Vranas, Steven J. Wagner, William J. Wainwright, Paul E. Walker, Robert E. Wall, Craig Walton, Douglas Walton, Eric Watkins, Richard A. Watson, Michael V. Wedin, Rudolph H. Weingartner, Paul Weirich, Paul J. Weithman, Carl Wellman, Howard Wettstein, Samuel C. Wheeler, Stephen A. White, Jennifer Whiting, Edward R. Wierenga, Michael Williams, Fred Wilson, W. Kent Wilson, Kenneth P. Winkler, John F. Wippel, Jan Woleński, Allan B. Wolter, Nicholas P. Wolterstorff, Rega Wood, W. Jay Wood, Paul Woodruff, Alison Wylie, Gideon Yaffe, Takashi Yagisawa, Yutaka Yamamoto, Keith E. Yandell, Xiaomei Yang, Dean Zimmerman, Günter Zoller, Catherine Zuckert, Michael Zuckert, Jack A. Zupko (J.A.Z.)
- Edited by Robert Audi, University of Notre Dame, Indiana
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- Book:
- The Cambridge Dictionary of Philosophy
- Published online:
- 05 August 2015
- Print publication:
- 27 April 2015, pp ix-xxx
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Resilience and corpus callosum microstructure in adolescence
- A. Galinowski, R. Miranda, H. Lemaitre, M.-L. Paillère Martinot, E. Artiges, H. Vulser, R. Goodman, J. Penttilä, M. Struve, A. Barbot, T. Fadai, L. Poustka, P. Conrod, T. Banaschewski, G. J. Barker, A. Bokde, U. Bromberg, C. Büchel, H. Flor, J. Gallinat, H. Garavan, A. Heinz, B. Ittermann, V. Kappel, C. Lawrence, E. Loth, K. Mann, F. Nees, T. Paus, Z. Pausova, J.-B. Poline, M. Rietschel, T. W. Robbins, M. Smolka, G. Schumann, J.-L. Martinot, the IMAGEN Consortium
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- Journal:
- Psychological Medicine / Volume 45 / Issue 11 / August 2015
- Published online by Cambridge University Press:
- 30 March 2015, pp. 2285-2294
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Background
Resilience is the capacity of individuals to resist mental disorders despite exposure to stress. Little is known about its neural underpinnings. The putative variation of white-matter microstructure with resilience in adolescence, a critical period for brain maturation and onset of high-prevalence mental disorders, has not been assessed by diffusion tensor imaging (DTI). Lower fractional anisotropy (FA) though, has been reported in the corpus callosum (CC), the brain's largest white-matter structure, in psychiatric and stress-related conditions. We hypothesized that higher FA in the CC would characterize stress-resilient adolescents.
MethodThree groups of adolescents recruited from the community were compared: resilient with low risk of mental disorder despite high exposure to lifetime stress (n = 55), at-risk of mental disorder exposed to the same level of stress (n = 68), and controls (n = 123). Personality was assessed by the NEO-Five Factor Inventory (NEO-FFI). Voxelwise statistics of DTI values in CC were obtained using tract-based spatial statistics. Regional projections were identified by probabilistic tractography.
ResultsHigher FA values were detected in the anterior CC of resilient compared to both non-resilient and control adolescents. FA values varied according to resilience capacity. Seed regional changes in anterior CC projected onto anterior cingulate and frontal cortex. Neuroticism and three other NEO-FFI factor scores differentiated non-resilient participants from the other two groups.
ConclusionHigh FA was detected in resilient adolescents in an anterior CC region projecting to frontal areas subserving cognitive resources. Psychiatric risk was associated with personality characteristics. Resilience in adolescence may be related to white-matter microstructure.