Frequency based localization of structural discrepancies

The intent of modal analysis is to develop a reliable model of a structure by working with the analytical and experimental modal properties of frequency, damping and mode shape. In addition to identifying these modal properties, it would be desirable to determine spatially which parts of the structure are modelled poorly or well. It is shown how the pattern of discrepancies in the analytical and experimental test values for the pole and the driving point zero frequencies of a structure can be linked to discrepancies in the mass or stiffness of the structural elements. The success of the procedure depends on the numerical conditioning of a modal reference matrix. Strategies to insure adequate numerical conditioning require a formulation which avoids geometric and energy storage symmetries of the structure, and ignores structural elements which contribute negligibly small potential or kinetic energy to the excited modes. Physical insight into the numerical conditioning problem is provided by a numerical example and by localization of a mass discrepancy in a real structure based on lab tests

AN EXAMINATION OF THE IMPACTS OF CHILDHOOD TRAUMA ON HEALTHY INTIMATE RELATIONSHIPS IN COLLEGE-AGED AFRICAN AMERICANS

For African Americans, the dynamics of relationships are rooted in childhood experiences of unconditional love, restraint, and respect. These experiences help individuals form their understanding of how relationships function. Experiencing healthy relationships has an enduring impact on social development and interpersonal relationships. However, regarding studies on childhood trauma and intimate relationships, there is insufficient literature that includes African American samples as the primary foci of the research. Due to gaps in extant literature, the present study aims to explore whether experiences of healthy intimate relationship in African Americans are associated with childhood trauma (neglect, emotional, sexual, and physical abuse). Using the concept of Adverse Childhood Experiences (ACEs; Felitti & Anda, 1998), the present study examined the extent to which trauma experienced in childhood serves as a predictor of healthy intimate relationship experiences, using a novel measure, the Healthy Intimate Relationship Assessment (HIRA; Shepard, 2019). Psychometric properties regarding the HIRA were explored to determine factor loadings and reliability. The study measured whether gender or counseling moderated the relationship between ACEs and healthy relationship factors as well. Findings suggest that 1) higher reported ACEs scores were associated with lower HIRA scores on the trust, honesty, and communication subscales, 2) participants that endorsed higher ACEs abuse and neglect clusters scores reported experiencing less trusting, honest, and communicative intimate relationships as outlined in the HIRA measure, and 3) gender and counseling experience did not attenuate the association between ACEs and HIRA scores. Implications of adverse childhood experiences on experiences in adult intimate relationships are discussed as well as future directions to consider when exploring similar research

Escarabajos (Coleoptera) de Perú: un muestreo de las familias. Mycetophagidae Leach 1815

The diversity of the family Mycetophagidae (Coleoptera) is summarized for Peru. Two genera are recorded (Litargus Erichson and Thrimolus Casey). Comments are given on classification and distribution of the family, as well as known biology and natural history.La diversidad de la familia Mycetophagidae (Coleoptera) se resume para Perú. Se registran dos géneros (Litargus Erichson y Thrimolus Casey). Se proporcionan comentarios sobre la clasificación y distribución de la familia, asi como la biología conocida y la historia natural

Structural response and input identification

Three major goals were delineated: (1) to develop a general method for determining the response of a structure to combined base and acoustic random excitation: (2) to develop parametric relationships to aid in the design of plates which are subjected to random force or random base excitation: (3) to develop a method to identify the individual acoustic and base input to a structure with only a limited number of measurement channels, when both types of excitation act simultaneously

Genetic ancestry of participants in the National Children's Study.

BackgroundThe National Children's Study (NCS) is a prospective epidemiological study in the USA tasked with identifying a nationally representative sample of 100,000 children, and following them from their gestation until they are 21 years of age. The objective of the study is to measure environmental and genetic influences on growth, development, and health. Determination of the ancestry of these NCS participants is important for assessing the diversity of study participants and for examining the effect of ancestry on various health outcomes.ResultsWe estimated the genetic ancestry of a convenience sample of 641 parents enrolled at the 7 original NCS Vanguard sites, by analyzing 30,000 markers on exome arrays, using the 1000 Genomes Project superpopulations as reference populations, and compared this with the measures of self-reported ethnicity and race. For 99% of the individuals, self-reported ethnicity and race agreed with the predicted superpopulation. NCS individuals self-reporting as Asian had genetic ancestry of either South Asian or East Asian groups, while those reporting as either Hispanic White or Hispanic Other had similar genetic ancestry. Of the 33 individuals who self-reported as Multiracial or Non-Hispanic Other, 33% matched the South Asian or East Asian groups, while these groups represented only 4.4% of the other reported categories.ConclusionsOur data suggest that self-reported ethnicity and race have some limitations in accurately capturing Hispanic and South Asian populations. Overall, however, our data indicate that despite the complexity of the US population, individuals know their ancestral origins, and that self-reported ethnicity and race is a reliable indicator of genetic ancestry

Space station integrated propulsion and fluid systems study

The program study was performed in two tasks: Task 1 addressed propulsion systems and Task 2 addressed all fluid systems associated with the Space Station elements, which also included propulsion and pressurant systems. Program results indicated a substantial reduction in life cycle costs through integrating the oxygen/hydrogen propulsion system with the environmental control and life support system, and through supplying nitrogen in a cryogenic gaseous supercritical or subcritical liquid state. A water sensitivity analysis showed that increasing the food water content would substantially increase the amount of water available for propulsion use and in all cases, the implementation of the BOSCH CO2 reduction process would reduce overall life cycle costs to the station and minimize risk. An investigation of fluid systems and associated requirements revealed a delicate balance between the individual propulsion and fluid systems across work packages and a strong interdependence between all other fluid systems

Mars Spacecraft Power System Development Final Report

Development of optimum Mariner spacecraft power system for application to future flyby and orbiter mission

Multilocus Genetic Investigation of Species Limits in the Caddo Mountain Salamander (Plethodon caddoensis)

Alexandra D. Hahn is an undergraduate student in the School of Biological Sciences at Louisiana Tech University. Donald B. Shepard is an Assistant Professor in the School of Biological Sciences at Louisiana Tech University

A generic key to the known larval Elmidae (Insecta: Coleoptera) of French Guiana

An identification key is provided for 21 larval types of Elmidae (riffle beetles) known to occur in French Guiana. Not all elmid genera known to occur in French Guiana are known in the larval stage. Nor are all the known larval types assigned to known elmid genera