73,837 research outputs found

    Nano-scale analysis of titanium dioxide fingerprint-development powders

    Get PDF
    Titanium dioxide based powders are regularly used in the development of latent fingerprints on dark surfaces. For analysis of prints on adhesive tapes, the titanium dioxide is suspended in a surfactant and used in the form of a small particle reagent (SPR). Analysis of commercially available products shows varying levels of effectiveness of print development, with some powders adhering to the background as well as the print. Scanning electron microscopy (SEM) images of prints developed with different powders show a range of levels of aggregation of particles. Analytical transmission electron microscopy (TEM) of the fingerprint powder shows TiO2 particles with a surrounding coating, tens of nanometres thick, consisting of Al and Si rich material. X ray photoelectron spectroscopy (XPS) is used to determine the composition and chemical state of the surface of the powders; with a penetration depth of approximately 10nm, this technique demonstrates differing Ti: Al: Si ratios and oxidation states between the surfaces of different powders. Levels of titanium detected with this technique demonstrate variation in the integrity of the surface coating. The thickness, integrity and composition of the Al/Si-based coating is related to the level of aggregation of TiO2 particles and efficacy of print development

    Emulating a flexible space structure: Modeling

    Get PDF
    Control Dynamics, in conjunction with Marshall Space Flight Center, has participated in the modeling and testing of Flexible Space Structures. Through the series of configurations tested and the many techniques used for collecting, analyzing, and modeling the data, many valuable insights have been gained and important lessons learned. This paper discusses the background of the Large Space Structure program, Control Dynamics' involvement in testing and modeling of the configurations (especially the Active Control Technique Evaluation for Spacecraft (ACES) configuration), the results from these two processes, and insights gained from this work

    Cost effective development of a national test bed

    Get PDF
    For several years, the Marshall Space Flight Center has pursued the coordinated development of a Large Space Structures (LSS) National Test Bed for the investigation of numerous technical issues involved in the use of LSS in space. The origins of this development, the current status of the various test facilities and the plans laid down for the next five years' activities are described. Particular emphasis on the control and structural interaction issues has been paid so far; however, immediately emerging are user applications (such as the proposed pinhole occulter facility). In the immediate future, such emerging technologies as smart robots and multibody interactions will be studied. These areas are covered

    Networks and marketing in small professional service businesses

    Get PDF
    Purpose ā€“ This paper investigates the link between networks and marketing and discusses the extent to which small professional service businesses use their networks for marketing activities. Both the structural and relational components of networks are considered to better understand what networks are and how they operate. Design/methodology/approach ā€“ The literature review identifies key elements of professional service businesses, networks and marketing activities. The primary research is qualitative by design and exploratory in nature. Data were collected from five small management consultancy businesses through in-depth interviews using semi-structured questionnaires. Findings - The study finds that small professional service businesses lack the business/marketing language to articulate their approaches and values. They are increasingly relying on collaboration to deliver changing services. Findings show that ā€˜core groupsā€™ are highly significant in the structure of their networks. Furthermore, while most connections are work related, networks are not strategically motivated. Linkages are strong and motivations to network and networking activities are both short and long term. Generating work and developing lasting collaborative relationships is based on similar values and interests. Originality/value ā€“ The study offers insight and practical understanding on the relations that small businesses have with their networks. It also builds and adds value to the theory of network and networking in both the small business field and professional services related industry

    Perceived Racial Discrimination and Nonadherence to Screening Mammography

    Full text link
    Objective. We examined whether African American women were as likely as White women to receive the results of a recent mammogram and to self-report results that matched the mammography radiology report (i.e., were adequately communicated). We also sought to determine whether the adequacy of communication was the same for normal and abnormal results. Methods. From a prospective cohort study of mammography screening, we compared self-reported mammogram results, which were collected by telephone interview, to results listed in the radiology record of 411 African American and 734 White women who underwent screening in 5 hospital-based facilities in Connecticut between October 1996 and January 1998. Using multivariate logistic regression, we identified independent predictors of inadequate communication of mammography results. Results. It was significantly more common for African American women to experience inadequate communication of screening mammography results compared with White women, after adjustment for sociodemographic, access-to-care, biomedical, and psychosocial factors. Abnormal mammogram results resulted in inadequate communication for African American women but not White women (PAfrican American women may not be receiving the full benefit of screening mammograms because of inadequate communication of results, particularly when mammography results are abnormal

    <i>ā€˜What retentionā€™ means to me</i>: the position of the adult learner in student retention

    Get PDF
    Studies of student retention and progression overwhelmingly appear adopt definitions that place the institution, rather than the student, at the centre. Retention is most often conceived in terms of linear and continuous progress between institutionally identified start and end points. This paper reports on research that considered data from 38 in-depth interviews conducted with individuals who had characteristics often associated with non-traditional engagement in higher education who between 2006 and 2010 had studied an ā€˜Introduction to HEā€™ module at one distance higher education institution, some of whom had progressed to further study at that institution, some of whom had not. The research deployed a life histories approach to seek a finer grained understanding of how individuals conceptualise their own learning journey and experience, in order to reflect on institutional conceptions of student retention. The findings highlight potential anomalies hidden within institutional retention rates ā€“ large proportions of the interview participants who were not ā€˜retainedā€™ by the institution reported successful progression to and in other learning institutions and environments, both formal and informal. Nearly all described positive perspectives on lifelong learning which were either engendered or improved by the learning undertaken. This attests to the complexity of individualsā€™ lives and provides clear evidence that institution-centric definitions of retention and progression are insufficient to create truly meaningful understanding of successful individual learning journeys and experiences. It is argued that only through careful consideration of the lived experience of students and a re-conception of measures of retention, will we be able to offer real insight into improving student retention

    Adequacy of Communicating Results From Screening Mammograms to African American and White Women

    Full text link
    Objective. We examined whether African American women were as likely as White women to receive the results of a recent mammogram and to self-report results that matched the mammography radiology report (i.e., were adequately communicated). We also sought to determine whether the adequacy of communication was the same for normal and abnormal results. Methods. From a prospective cohort study of mammography screening, we compared self-reported mammogram results, which were collected by telephone interview, to results listed in the radiology record of 411 African American and 734 White women who underwent screening in 5 hospital-based facilities in Connecticut between October 1996 and January 1998. Using multivariate logistic regression, we identified independent predictors of inadequate communication of mammography results. Results. It was significantly more common for African American women to experience inadequate communication of screening mammography results compared with White women, after adjustment for sociodemographic, access-to-care, biomedical, and psychosocial factors. Abnormal mammogram results resulted in inadequate communication for African American women but not White women (P\u3c.001). Conclusions. African American women may not be receiving the full benefit of screening mammograms because of inadequate communication of results, particularly when mammography results are abnormal

    Neighborhood and Individual Level Socioeconomic Variation in Perceptions of Racial Discrimination

    Full text link
    In approaching the study of racial discrimination and health, the neighborhood and individual-level antecedents of perceived discrimination need further exploration. We investigated the relationship between neighborhood and individual-level socioeconomic position (SEP), neighborhood racial composition, and perceived racial discrimination in a cohort of African-American and White women age 40-79 from Connecticut, USA. Design. The logistic regression analysis included 1249 women (39% African- American and 61% White). Neighborhood-level SEP and racial composition were determined using 1990 census tract information. Individual-level SEP indicators included income, education, and occupation. Perceived racial discrimination was measured as lifetime experience in seven situations. Results. For African-American women, living in the most disadvantaged neighborhoods was associated with fewer reports of racial discrimination (odds ratio (OR) 0.44; 95% confidence interval (CI) 0.26, 0.75), with results attenuated after adjustment for individual-level SEP (OR 0.54, CI: 0.29, 1.03), and additional adjustment for neighborhood racial composition (OR 0.70, CI: 0.30, 1.63). African-American women with 12 years of education or less were less likely to report racial discrimination, compared with women with more than 12 years of education (OR 0.57, CI: 0.33, 0.98 (12 years); OR 0.51, CI: 0.26, 0.99 (less than 12 years)) in the fully adjusted model. For White women, neither neighborhood-level SEP nor individual-level SEP was associated with perceived racial discrimination. Conclusion. Individual and neighborhood-level SEP may be important in understanding how racial discrimination is perceived, reported, processed, and how it may influence health. In order to fully assess the role of racism in future studies, inclusion of additional dimensions of discrimination may be warranted
    • ā€¦
    corecore