Object Substitution Masking in Schizophrenia: An Event-Related Potential Analysis

Schizophrenia patients exhibit deficits on visual processing tasks, including visual backward masking, and these impairments are related to deficits in higher-level processes. In the current study we used electroencephalography techniques to examine successive stages and pathways of visual processing in a specialized masking paradigm, four-dot masking, which involves masking by object substitution. Seventy-six schizophrenia patients and 66 healthy controls had event-related potentials (ERPs) recorded during four-dot masking. Target visibility was manipulated by changing stimulus onset asynchrony (SOA) between the target and mask, such that performance decreased with increasing SOA. Three SOAs were used: 0, 50, and 100 ms. The P100 and N100 perceptual ERPs were examined. Additionally, the visual awareness negativity (VAN) to correct vs. incorrect responses, an index of reentrant processing, was examined for SOAs 50 and 100 ms. Results showed that patients performed worse than controls on the behavioral task across all SOAs. The ERP results revealed that patients had significantly smaller P100 and N100 amplitudes, though there was no effect of SOA on either component in either group. In healthy controls, but not patients, N100 amplitude correlated significantly with behavioral performance at SOAs where masking occurred, such that higher accuracy correlated with a larger N100. Healthy controls, but not patients, exhibited a larger VAN to correct vs. incorrect responses. The results indicate that the N100 appears to be related to attentional effort in the task in controls, but not patients. Considering that the VAN is thought to reflect reentrant processing, one interpretation of the findings is that patients’ lack of VAN response and poorer performance may be related to dysfunctional reentrant processing

Increased typhoon activity in the Pacific deep tropics driven by Little Ice Age circulation changes

Author Posting. © The Author(s), 2020. This is the author's version of the work. It is posted here by permission of Nature Research for personal use, not for redistribution. The definitive version was published in Bramante, J. F., Ford, M. R., Kench, P. S., Ashton, A. D., Toomey, M. R., Sullivan, R. M., Karnauskas, K. B., Ummenhofer, C. C., & Donnelly, J. P. (2020). Increased typhoon activity in the Pacific deep tropics driven by Little Ice Age circulation changes. Nature Geoscience, 13, 806–811. doi:10.1038/s41561-020-00656-2.The instrumental record reveals that tropical cyclone activity is sensitive to oceanic and atmospheric variability on inter-annual and decadal scales. However, our understanding of the influence of climate on tropical cyclone behaviour is restricted by the short historical record and the sparseness of prehistorical reconstructions, particularly in the western North Pacific, where coastal communities suffer loss of life and livelihood from typhoons annually. Here, to explore past regional typhoon dynamics, we reconstruct three millennia of deep tropical North Pacific cyclogenesis. Combined with existing records, our reconstruction demonstrates that low-baseline typhoon activity prior to 1350 ce was followed by an interval of frequent storms during the Little Ice Age. This pattern, concurrent with hydroclimate proxy variability, suggests a centennial-scale link between Pacific hydroclimate and tropical cyclone climatology. An ensemble of global climate models demonstrates a migration of the Pacific Walker circulation and variability in two Pacific climate modes during the Little Ice Age, which probably contributed to enhanced tropical cyclone activity in the tropical western North Pacific. In the next century, projected changes to the Pacific Walker circulation and expansion of the tropics will invert these Little Ice Age hydroclimate trends, potentially reducing typhoon activity in the deep tropical Pacific.This work was supported by the Strategic Environmental Research and Development Program (SERDP RC-2336). C.C.U. acknowledges support from NSF under AGS-1602455. We thank student intern D. Carter for extensive labwork on core LTD3. We acknowledge the WCRP’s Working Group on Coupled Modelling, which is responsible for CMIP, and we thank the climate modelling groups for producing and making available their model output. CMIP5 model output was provided by the WHOI CMIP5 Community Storage Server via their website: http://cmip5.whoi.edu/. Any use of trade, firm or product names is for descriptive purposes only and does not imply endorsement by the US Government.2021-05-1

Future research directions on the "elusive" white shark

White sharks, Carcharodon carcharias, are often described as elusive, with little information available due to the logistical difficulties of studying large marine predators that make long-distance migrations across ocean basins. Increased understanding of aggregation patterns, combined with recent advances in technology have, however, facilitated a new breadth of studies revealing fresh insights into the biology and ecology of white sharks. Although we may no longer be able to refer to the white shark as a little-known, elusive species, there remain numerous key questions that warrant investigation and research focus. Although white sharks have separate populations, they seemingly share similar biological and ecological traits across their global distribution. Yet, white shark’s behavior and migratory patterns can widely differ, which makes formalizing similarities across its distribution challenging. Prioritization of research questions is important to maximize limited resources because white sharks are naturally low in abundance and play important regulatory roles in the ecosystem. Here, we consulted 43 white shark experts to identify these issues. The questions listed and developed here provide a global road map for future research on white sharks to advance progress toward key goals that are informed by the needs of the research community and resource managers

Comparison of Convergence Acceleration Algorithms Across Several Numerical Models of 1-Dimensional Heat Conduction

The one dimensional transient heat conduction equation was numerically modeled through matrix diagonalization and three time-discretization schemes. The discrete methods were first-order backward, second-order backward, and implicit finite difference schemes. All simulations used the central difference formula in the space dimension. Two relevant physical systems were considered: a uniformly conducting slab and a melting block of ice. The latter lead to a moving boundary system, or Stefan problem. The multiphysics of melting was numerically modeled through alternating updates of temperature and melt front profiles. Iterative simulations were run with regularly refined discretization meshes in both systems. In the case of the conducting slab, temperature at a fixed point in space and time was considered. For the Stefan problem, the melt front movement after a set time was the physical solution of interest. The accuracy of the convergent results was increased using Richardson acceleration and the Wynn's epsilon algorithm. Accuracy was improved for the moving boundary problem as well, but to a significantly lesser degree. The relative errors improved by five and two orders of magnitude for the conducting block and melting ice simulations, respectively. These relative errors were used to determine that matrix diagonalization is the most accurate numerical solution among the four considered. In both simulation convergence and acceleration potential, matrix diagonalization was superior to the implicit and explicit discretization solutions. However, matrix diagonalization required significantly more computational time. With the enhancement of convergence acceleration, the finite difference schemes obtained similar relative errors to the diagonalization model. This demonstrated the value of convergence acceleration in the classic dilemma for every programmer. There is always a balance struck between model sophistication, accuracy, and computational time. Convergence acceleration allows for a simpler numerical model to achieve comparable accuracy, and in less time than that required for sophisticated numerical models. The numerical models were also compared for stability through parameters that arose in each simulation. These parameters were the Courant-Friederichs-Lewy (CFL) condition and diagonalized eigenvalues. Though diagonalization was found to be the most accurate, it was determined that the backwards finite difference solutions are the easiest to evaluate for stability. In these solution methods, the CFL value allows the stability to be determined prior to running the simulation

Lack of vitamin D signalling per se does not aggravate cardiac functional impairment induced by myocardial infarction in mice.

Epidemiological studies have linked vitamin D deficiency to an increased incidence of myocardial infarction and support a role for vitamin D signalling in the pathophysiology of myocardial infarction. Vitamin D deficiency results in the development of secondary hyperparathyroidism, however, the role of secondary hyperparathyroidism in the pathophysiology of myocardial infarction is not known. Here, we aimed to explore further the secondary hyperparathyroidism independent role of vitamin D signalling in the pathophysiology of myocardial infarction by inducing experimental myocardial infarction in 3-month-old, male, wild-type mice and in mice lacking a functioning vitamin D receptor. In order to prevent secondary hyperparathyroidism in vitamin D receptor mutant mice, all mice were maintained on a rescue diet enriched with calcium, phosphorus, and lactose. Surprisingly, survival rate, cardiac function as measured by echocardiography and intra-cardiac catheterisation and cardiomyocyte size were indistinguishable between normocalcaemic vitamin D receptor mutant mice and wild-type controls, 2 and 8 weeks post-myocardial infarction. In addition, the myocardial infarction-induced inflammatory response was similar in vitamin D receptor mutants and wild-type mice, as evidenced by a comparable upregulation in cardiac interleukin-1-β and tumor-necrosis-factor-α mRNA abundance and similar elevations in circulating interleukin-1-β and tumor-necrosis-factor-α. Our data suggest that the lack of vitamin D signalling in normocalcaemic vitamin D receptor mutants has no major detrimental effect on cardiac function and outcome post-myocardial infarction. Our study may have important clinical implications because it suggests that the secondary hyperparathyroidism induced by vitamin D deficiency, rather than the lack of vitamin D signalling per se, may negatively impact cardiac function post-myocardial infarction

What do alternate assessments of alternate academic achievement standards measure? A multitrait-multimethod analysis

This study featured validity evidence for scores from states' alternate assessments of alternate academic achievement standards (AA-AASs). It evaluated students from 6 states who were eligible for an AA-AAS concurrently with measures of academic competence and adaptive behavior. The investigators also assessed students with disabilities who were not eligible for an AA-AAS by using the same measures, as well as by using general achievement tests. The main findings included that AA-AAS reading and math scores may reflect a unitary construct, that AA-AAS scores are highly related to adaptive behavior but also relate to academic competence and achievement, and that all these scores represent unique but overlapping constructs. These results have implications for AA-AAS developers and teachers working with students with significant cognitive disabilities

The synthesis and unusual luminescence behavior of 1,1-dimethyl-2,5-di(2-naphthyl)-3,4-diphenylsilole

The synthesis and spectroscopic characteristics, including quantum yield and luminescence lifetime, of1,1-dimethyl-2,5-di(2-naphthyl)-3,4-diphenylsilole are described. Unlike most aryl substituted siloles, the compound displays very efficient luminescence in solution, but does not exhibit aggregation-induced emission. In addition, the solution-phase emission intensity demonstrates an unusual time dependence

Increased typhoon activity in the Pacific deep tropics driven by Little Ice Age circulation changes

The instrumental record reveals that tropical cyclone activity is sensitive to oceanic and atmospheric variability on inter-annual and decadal scales. However, our understanding of climate’s influence on tropical cyclone behavior is restricted by the short historical record and sparse prehistorical reconstructions, particularly in the western North Pacific where coastal communities suffer loss of life and livelihood from typhoons annually. Here we reconstruct three millennia of deep tropical North Pacific cyclogenesis and compare with other records to explore past regional typhoon dynamics. These records demonstrate low baseline activity prior to 1350 C.E. followed by a rapid culmination in activity during the Little Ice Age. This pattern is concurrent with hydroclimate proxy variability, suggesting a centennial-scale link between Pacific hydroclimate and tropical cyclone climatology. Using an ensemble of global climate models, we demonstrate that migration of the Pacific Walker circulation and variability in two Pacific climate modes during the Little Ice Age contributed to enhanced tropical cyclone activity in the tropical western North Pacific. Changes to Walker Circulation and expansion of the tropics projected for the next century invert Little Ice Age hydroclimate trends, potentially reducing typhoon activity in the deep tropical Pacific.This project was supported by the Strategic Environmental Research and Development Program through award SERDP RC-233