Quantitative Spectrographic Analysis of Plant Tissue

Quantitative spectrographic analysis of corn leaf as a typical plant tissue has been carried out for several elements (Mg, Ca, Si), using a 1100-volt AC arc between carbon electrodes as a source. Tests have been made on various internal standards excitation conditions, etc., attempting to increase accuracy and reproducibility. Data and variations typical of the present status of the investigation are presented

A Heat Vaporization Experiment for Elementary Laboratory

An electric heating coil is used in an ordinary pint vacuum bottle to evaporate water under steady state conditions. The system is used on a platform balance; the heat of vaporization is determined from total energy input and total change of weight. Sources of error are discussed and accuracy obtainable in actual use is indicated

Reply to comment by B. Andreotti et al. on "Solving the mystery of booming sand dunes"

This reply addresses three main issues raised in the comment of Andreotti et al. [2008]. First, the turning of ray paths in a granular material does not preclude the propagation of body waves and the resonance condition described by Vriend et al. [2007]. The waveguide model still holds in the dune for the observed velocities, even with a velocity increase with depth as implied by Andreotti et al. [2008]. Secondly, the method of initiation of spontaneous avalanching does not influence the booming frequency. The frequency is independent of the source once sustained booming starts; it depends on the subsurface structure of the dune. Thirdly, if all data points from Vriend et al. [2007] are included in the analysis (and not an average or selection), no correlation is observed between the sustained booming frequency and average particle diameter

Solving the mystery of booming sand dunes

Desert booming can be heard after a natural slumping event or during a sand avalanche generated by humans sliding down the slip face of a large dune. The sound is remarkable because it is composed of one dominant audible frequency (70 to 105 Hz) plus several higher harmonics. This study challenges earlier reports that the dunes’ frequency is a function of average grain size by demonstrating through extensive field measurements that the booming frequency results from a natural waveguide associated with the dune. The booming frequency is fixed by the depth of the surficial layer of dry loose sand that is sandwiched between two regions of higher compressional body wave velocity. This letter presents measurements of the booming frequencies, compressional wave velocities, depth of surficial layer, along with an analytical prediction of the frequency based on constructive interference of propagating waves generated by avalanching along the dune surface

Assessing Exposure to Violence Using Multiple Informants: Application of Hierarchical Linear Model

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72634/1/1469-7610.00692.pd

CONCEPTUAL DESIGN OF THE USMC FUTURE VERTICAL LIFT (FVL) LIVING LAB

The United States Marine Corps (USMC) is developing the Future Vertical Lift (FVL) system that will rely heavily on Marine-machine teaming, a complex process that requires further development. The development of a living lab (LL)—a multi-function network of simulators that will serve as the platform for testing, experimenting, and training new technologies and ideas for how the FVL will operate—will help mitigate Marine-machine collaboration and trust issues. This capstone studies the options and requirements for developing a LL through interviews, research that focuses on existing technologies and operational concepts, and Model-Based Systems Engineering tools using a systems engineering approach. The report includes a detailed needs and requirements analysis, stakeholder analysis, and functional design. The team presents a conceptual design, that includes the system architecture, comprising of system, function and physical views, system lifecycle, and the evaluation criteria for a LL. The final product is a set of use cases and concepts of operation. The USMC needs a new approach that supports rapid and relevant upgrades that optimizes the system lifecycle and keeps the Marine in mind. This team recommends the USMC consider these findings and continue researching and developing a LL.ONR Arlington, VA 22203Civilian, Department of the NavyCivilian, Department of the NavyCivilian, Department of the NavyCivilian, Department of the NavyCivilian, Department of the NavyCivilian, Department of the NavyApproved for public release. Distribution is unlimited

Diffusion Tensor Imaging in Sport-Related Concussion: A Systematic Review Using an a priori Quality Rating System

Diffusion tensor imaging (DTI) of brain white matter (WM) may be useful for characterizing the nature and degree of brain injury after sport-related concussion (SRC) and assist in establishing objective diagnostic and prognostic biomarkers. This study aimed to conduct a systematic review using an a priori quality rating strategy to determine the most consistent DTI-WM changes post-SRC. Articles published in English (until June 2020) were retrieved by standard research engine and gray literature searches (N = 4932), using PRISMA guidelines. Eligible studies were non-interventional naturalistic original studies that conducted DTI within 6 months of SRC in current athletes from all levels of play, types of sports, and sex. A total of 29 articles were included in the review, and after quality appraisal by two raters, data from 10 studies were extracted after being identified as high quality. High-quality studies showed widespread moderate-to-large WM differences when SRC samples were compared to controls during the acute to early chronic stage (days to weeks) post-SRC, including both increased and decreased fractional anisotropy and axial diffusivity and decreased mean diffusivity and radial diffusivity. WM differences remained stable in the chronic stage (2-6 months post-SRC). DTI metrics were commonly associated with SRC symptom severity, although standardized SRC diagnostics would improve future research. This indicates that microstructural recovery is often incomplete at return to play and may lag behind clinically assessed recovery measures. Future work should explore interindividual trajectories to improve understanding of the heterogeneous and dynamic WM patterns post-SRC

A wellness study of 108 individuals using personal, dense, dynamic data clouds.

Personal data for 108 individuals were collected during a 9-month period, including whole genome sequences; clinical tests, metabolomes, proteomes, and microbiomes at three time points; and daily activity tracking. Using all of these data, we generated a correlation network that revealed communities of related analytes associated with physiology and disease. Connectivity within analyte communities enabled the identification of known and candidate biomarkers (e.g., gamma-glutamyltyrosine was densely interconnected with clinical analytes for cardiometabolic disease). We calculated polygenic scores from genome-wide association studies (GWAS) for 127 traits and diseases, and used these to discover molecular correlates of polygenic risk (e.g., genetic risk for inflammatory bowel disease was negatively correlated with plasma cystine). Finally, behavioral coaching informed by personal data helped participants to improve clinical biomarkers. Our results show that measurement of personal data clouds over time can improve our understanding of health and disease, including early transitions to disease states

Stories tell us? Political narrative, demes, and the transmission of knowledge through culture

This paper compares two institutions of storytelling, mainstream national narratives and self-represented digital storytelling. It considers the centenary of World War 1, especially the Gallipoli campaign (1915) and its role in forming Australian ‘national character’. Using the new approach of cultural science, it investigates storytelling as a means by which cultures make and bind groups or ‘demes’. It finds that that demic (group-made) knowledge trumps individual experience, and that self-representation (digital storytelling) tends to copy the national narrative, even when the latter is known not to be true. The paper discusses the importance of culture in the creation of knowledge, arguing that if the radical potential of digital storytelling is to be understood – and realised – then a systems (as opposed to behavioural) approach to communication is necessary. Without a new model of knowledge, it seems we are stuck with repetition of the same old story

The Moderating Effects of Peer and Parental Support on the Relationship Between Vicarious Victimization and Substance Use

General strain theory (GST) hypothesizes that youth are more likely to engage in delinquency when they experience vicarious victimization, defined as knowing about or witnessing violence perpetrated against others, but that this relationship may be attenuated for those who receive social support from significant others. Based on prospective data from youth aged 8 to 17 participating in the Project on Human Development in Chicago Neighborhoods (PHDCN), this article found mixed support for these hypotheses. Controlling for prior involvement in delinquency, as well as other risk and protective factors, adolescents who reported more vicarious victimization had an increased likelihood of alcohol use in the short term, but not the long term, and victimization was not related to tobacco or marijuana use. Peer support did not moderate the relationship between vicarious victimization and substance use, but family support did. In contrast to strain theory’s predictions, the relationship between vicarious victimization and substance use was stronger for those who had higher compared with lower levels of family support. Implications of these findings for strain theory and future research are discussed