The unity and diversity of executive functions: A systematic review and re-analysis of latent variable studies.

Confirmatory factor analysis (CFA) has been frequently applied to executive function measurement since first used to identify a three-factor model of inhibition, updating, and shifting; however, subsequent CFAs have supported inconsistent models across the life span, ranging from unidimensional to nested-factor models (i.e., bifactor without inhibition). This systematic review summarized CFAs on performance-based tests of executive functions and reanalyzed summary data to identify best-fitting models. Eligible CFAs involved 46 samples (N = 9,756). The most frequently accepted models varied by age (i.e., preschool = one/two-factor; school-age = three-factor; adolescent/adult = three/nested-factor; older adult = two/three-factor), and most often included updating/working memory, inhibition, and shifting factors. A bootstrap reanalysis simulated 5,000 samples from 21 correlation matrices (11 child/adolescent; 10 adult) from studies including the three most common factors, fitting seven competing models. Model results were summarized as the mean percent accepted (i.e., average rate at which models converged and met fit thresholds: CFI ≥ .90/RMSEA ≤ .08) and mean percent selected (i.e., average rate at which a model showed superior fit to other models: ΔCFI ≥ .005/.010/ΔRMSEA ≤ -.010/-.015). No model consistently converged and met fit criteria in all samples. Among adult samples, the nested-factor was accepted (41-42%) and selected (8-30%) most often. Among child/adolescent samples, the unidimensional model was accepted (32-36%) and selected (21-53%) most often, with some support for two-factor models without a differentiated shifting factor. Results show some evidence for greater unidimensionality of executive function among child/adolescent samples and both unity and diversity among adult samples. However, low rates of model acceptance/selection suggest possible bias toward the publication of well-fitting but potentially nonreplicable models with underpowered samples. (PsycINFO Database Record (c) 2018 APA, all rights reserved)

In Vivo Delivery of Nitric Oxide-Sensing, Single-Walled Carbon Nanotubes

Detection of nitric oxide (NO) in vivo by single-walled carbon nanotubes (SWNT) is based on the fluorescent properties of SWNT and the ability of NO to quench the fluorescence signal. Alterations of the signal can be utilized to detect a small molecule in vivo that has not previously been possible by other assay techniques. The protocols described here explain the techniques used to prepare NO-detecting SWNTs and to administer them to mice by both intravenous and subcutaneous routes. These techniques can also be utilized with other SWNT sensors as well as non-SWNT sensorNational Institutes of Health (T32 Training Grant in Environmental Toxicology ES007020

Avalanche Dynamics in Wet Granular Materials

We have studied the dynamics of avalanching wet granular media in a rotating drum apparatus. Quantitative measurements of the flow velocity and the granular flux during avalanches allow us to characterize novel avalanche types unique to wet media. We also explore the details of viscoplastic flow (observed at the highest liquid contents) in which there are lasting contacts during flow, leading to coherence across the entire sample. This coherence leads to a velocity independent flow depth at high rotation rates and novel robust pattern formation in the granular surface.Comment: 5 pages, 3 figures in color, REVTeX4, for smaller pdfs see http://angel.elte.hu/~tegzes/condmat.htm

Testing a glacial erosion rule using hang heights of hanging valleys, Jasper National Park, Alberta, Canada

Acknowledgments. The glaciology group at the University of Alaska Fairbanks provided constructive feedback. Comments from R. S. Anderson, B. Hallet, B. Hubbard, J. Tomkin, and S. Tulaczyk improved the manuscript.In most models of glacial erosion, glacier sliding velocity is hypothesized to control rates of bedrock erosion. If this hypothesis is correct, then the elevation difference between hanging and trunk valley floors, the hang height, should be dictated by the relative sliding velocities of the glaciers that occupied these valleys. By considering sliding velocity to be proportional to balance velocity and using mass continuity, hang height is expressed in terms of glacier catchment areas, slopes, and widths, which can be estimated for past glaciers from the morphology of glacial valleys. These parameters were estimated for 46 hanging valleys and their trunk valleys in three adjacent regions of Jasper National Park. The variability in valley morphology can account for 55–85% of the hang height variability if erosion rate scales with balance velocity raised to a power of 1/3. This correspondence is in spite of spatial variations in glaciation duration, snow accumulation rates, and other variables that likely affected hang heights but cannot be readily estimated and so are not included in our formulation. Thus it appears that balance velocity, and by extension, sliding velocity if the two are proportional, may be a reasonable control variable for assessing erosion rate.Ye

Deficits in agency in schizophrenia, and additional deficits in body image, body schema, and internal timing, in passivity symptoms

Individuals with schizophrenia, particularly those with passivity symptoms, may not feel in control of their actions, believing them to be controlled by external agents. Cognitive operations that contribute to these symptoms may include abnormal processing in agency as well as body representations that deal with body schema and body image. However, these operations in schizophrenia are not fully understood, and the questions of general versus specific deficits in individuals with different symptom profiles remain unanswered. Using the projected-hand illusion (a digital video version of the rubber-hand illusion) with synchronous and asynchronous stroking (500 ms delay), and a hand laterality judgment task, we assessed sense of agency, body image, and body schema in 53 people with clinically stable schizophrenia (with a current, past, and no history of passivity symptoms) and 48 healthy controls. The results revealed a stable trait in schizophrenia with no difference between clinical subgroups (sense of agency) and some quantitative (specific) differences depending on the passivity symptom profile (body image and body schema). Specifically, a reduced sense of self-agency was a common feature of all clinical subgroups. However, subgroup comparisons showed that individuals with passivity symptoms (both current and past) had significantly greater deficits on tasks assessing body image and body schema, relative to the other groups. In addition, patients with current passivity symptoms failed to demonstrate the normal reduction in body illusion typically seen with a 500 ms delay in visual feedback (asynchronous condition), suggesting internal timing problems. Altogether, the results underscore self-abnormalities in schizophrenia, provide evidence for both trait abnormalities and state changes specific to passivity symptoms, and point to a role for internal timing deficits as a mechanistic explanation for external cues becoming a possible source of self-body input

Recognition of specific sialoglycan structures by oral streptococci impacts the severity of endocardial infection.

Streptococcus gordonii and Streptococcus sanguinis are primary colonizers of the tooth surface. Although generally non-pathogenic in the oral environment, they are a frequent cause of infective endocarditis. Both streptococcal species express a serine-rich repeat surface adhesin that mediates attachment to sialylated glycans on mucin-like glycoproteins, but the specific sialoglycan structures recognized can vary from strain to strain. Previous studies have shown that sialoglycan binding is clearly important for aortic valve infections caused by some S. gordonii, but this process did not contribute to the virulence of a strain of S. sanguinis. However, these streptococci can bind to different subsets of sialoglycan structures. Here we generated isogenic strains of S. gordonii that differ only in the type and range of sialoglycan structures to which they adhere and examined whether this rendered them more or less virulent in a rat model of endocarditis. The findings indicate that the recognition of specific sialoglycans can either enhance or diminish pathogenicity. Binding to sialyllactosamine reduces the initial colonization of mechanically-damaged aortic valves, whereas binding to the closely-related trisaccharide sialyl T-antigen promotes higher bacterial densities in valve tissue 72 hours later. A surprising finding was that the initial attachment of streptococci to aortic valves was inversely proportional to the affinity of each strain for platelets, suggesting that binding to platelets circulating in the blood may divert bacteria away from the endocardial surface. Importantly, we found that human and rat platelet GPIbα (the major receptor for S. gordonii and S. sanguinis on platelets) display similar O-glycan structures, comprised mainly of a di-sialylated core 2 hexasaccharide, although the rat GPIbα has a more heterogenous composition of modified sialic acids. The combined results suggest that streptococcal interaction with a minor O-glycan on GPIbα may be more important than the over-all affinity for GPIbα for pathogenic effects

Quantitative Tissue Spectroscopy of Near Infrared Fluorescent Nanosensor Implants

Implantable, near infrared (nIR) fluorescent nanosensors are advantageous for in vivo monitoring of biological analytes since they can be rendered selective for particular target molecule while utilizing their unique optical properties and the nIR tissue transparency window for information transfer without an internal power source or telemetry. However, basic questions remain regarding the optimal encapsulation platform, geometrical properties, and concentration ranges required for effective signal to noise ratio through biological tissue. In this work, we systematically explore these variables quantitatively to optimize the performance of such optical nanosensors for biomedical applications. We investigate both alginate and polyethylene glycol (PEG) as model hydrogel systems, encapsulating d(GT)[subscript 15] ssDNA-wrapped single walled carbon nanotubes (SWNT) as model fluorescent nanoparticle sensors, responsive to riboflavin. Hydrogel sensors implanted 0.5 mm into thick tissue samples cause 50% reduction of initial fluorescence intensity, allowing an optical detection limit of 5.4 mm and 5.1 mm depth in tissue for alginate and PEG gels, respectively, at a SWNT concentration of 10 mg L−1, and 785 nm laser excitation of 80 mW and 30 s exposure. These findings are supported with in vivo nIR fluorescent imaging of SWNT hydrogels implanted subcutaneously in mice. For the case of SWNT, we find that the alginate system is preferable in terms of emission intensity, sensor response, rheological properties, and shelf life.National Institutes of Health (U.S.) (T32 Training Grant in Environmental Toxicology ES007020)National Cancer Institute (U.S.) (Grant P01 CA26731)National Institute of Environmental Health Sciences (Grant P30 ES002109)Arnold and Mabel Beckman Foundation (Young Investigator Award)National Science Foundation (U.S.) (Presidential Early Career Award for Scientists and Engineers)MIT-Technion FellowshipSamsung Scholarship FoundationSanofi Aventis (Firm) (Biomedical Innovation Grant

Covariant Quantization of d=4 Brink-Schwarz Superparticle with Lorentz Harmonics

Covariant first and second quantization of the free d=4 massless superparticle are implemented with the introduction of purely gauge auxiliary spinor Lorentz harmonics. It is shown that the general solution of the condition of maslessness is a sum of two independent chiral superfields with each of them corresponding to finite superspin. A translationally covariant, in general bijective correspondence between harmonic and massless superfields is constructed. By calculation of the commutation function it is shown that in the considered approach only harmonic fields with correct connection between spin and statistics and with integer negative homogeneity index satisfy the microcausality condition. It is emphasized that harmonic fields that arise are reducible at integer points. The index spinor technique is used to describe infinite-component fields of finite spin; the equations of motion of such fields are obtained, and for them Weinberg's theorem on the connection between massless helicity particles and the type of nongauge field that describes them is generalized.Comment: V2: 1 + 26 pages, published versio