165 research outputs found

    Magnetic resonance imaging findings in children with spasmus nutans

    Get PDF
    Background Spasmus nutans (SN) is a rare pediatric ophthalmologic syndrome characterized by nystagmus, head bobbing, and abnormal head positioning. Historically, SN has been associated with underlying optic pathway gliomas (OPG); however, evidence of this association is based primarily on a small number of isolated case reports. Prior retrospective analyses have found the rate of OPG to be <2%, but these studies only intermittently used neuroimaging with computed tomography, which has limited sensitivity for detection of small lesions in the optic pathway. The purpose of this study was to investigate the association of SN with intracranial abnormalities, particularly OPG, using magnetic resonance imaging of the brain and orbits. Methods Neuroradiology databases at three institutions spanning January 2010 to May 2016 were queried for examinations ordered for evaluation of SN; MRI examinations of the brain and/or orbits were included and evaluated for OPG and other structural abnormalities. Medical records were reviewed to confirm a diagnosis of SN, presence of other underlying neurological disease, or preexisting diagnoses. Results A total of 40 patients with eligible MRI examinations were identified. None had optic nerve pathway gliomas. Two children had optic nerve hypoplasia; no other patients had optic pathway abnormalities. None had intracranial or orbital masses. MRI examinations were normal in 25 patients. Conclusions This series represents the largest collection of MRI examinations for SN in the literature to date and shows no association between OPG and SN. In children presenting with SN but no other findings suggesting OPG or neurological abnormalities, neuroimaging may not be required

    An analysis of the main project organizational structures: advantages, disadvantages, and factors affecting their selection

    Get PDF
    Generally, we can define project organizational structures as organizational forms, based on temporary teams that are created to perform particular tasks and disappear after achieving the established goals. Whereas simple projects may require a limited number of steps and specializations, complex projects may be composed of plentiful of steps and require diverse and different specializations. As the project increases in size and design more units and specializations are added to the organizational structure contributing to both more vertical and horizontal organizational differentiation. Thus, when designing a project organizational structure the following questions must be answered: How many different specializations are included in the design of the project? How are the interrelatedness between the different elements of the project and between the different specializations? How many different activities are to be managed? In this paper, we analyse the three generic project organizational structures that are presented in the extant literature; functional, pure project, and matrix, together with their advantages and disadvantages. Furthermore, the most important factors that should be considered when designing a proper organizational structure are also analysed

    Managing Coopetition in Supplier Networks:A Paradox Perspective

    Get PDF
    Scholars in the field of supply chain management have started to embrace the idea of simultaneous cooperation and competition (coopetition) in supplier networks but have mainly looked at coopetition from a structural perspective. In this article, we complement the structural view with a paradox perspective to investigate the competitive tensions that evolve when buying firms are trying to engage both forces simultaneously in their relations with core suppliers. Our comparative case study of four major carmakers reveals different strategies buying firms use to manage coopetition in their supplier networks, the responses they trigger from their suppliers, and the resulting paradoxical tensions. Our inductive analysis reveals that irrespective of the managing approach chosen, the coopetition capabilities of the buying firm determines whether negative tension dynamics can be avoided. At the core of such coopetition capabilities are evaluative capabilities allowing the buyer to provide cost improvement suggestions to suppliers for the sake of joint value creation and to control the division of value appropriation through a deeper understanding of the supplier's cost structures. By highlighting the nature of coopetition capabilities as organizational capabilities, we also contribute to paradox research, going beyond its current focus on the individual cognitions of managers

    Establishing LA VIDA: A Community-Based Partnership to Prevent Intimate Violence against Latina Women

    Full text link
    LA VIDA—the Southwest Detroit Partnership to Prevent Intimate Violence Against Latina Women— evolved in response to community concern about the problem of intimate partner violence (IPV) and the lack of culturally competent preventive and support services for Latino women and men in southwest Detroit. Since 1997, diverse organizations have mobilized as a community-academic partnership to ensure the availability, accessibility, and utilization of IPV services. This article describes and analyzes the evolution of LA VIDA within a community-based participatory research framework using a case study approach that draws on multiple data sources including group and individual interviews and field notes. The challenges and lessons learned in addressing a complex multifaceted problem such as IPV in an ethnic minority community are highlighted in an examination of the process of mobilizing diverse organizations, conducting community diagnosis and needs assessment activities, establishing goals and objectives within a social ecological framework, and integrating evaluation during the development phase.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66991/2/10.1177_109019819902600606.pd

    Anti-envelope antibody responses in individuals at high risk of hepatitis C virus who resist infection

    Get PDF
    Summary: Injection drug users uninfected by hepatitis C virus (HCV) despite likely repeated exposure through high-risk behaviour are well documented. Factors preventing infection in these individuals are incompletely understood. Here, we looked for anti-HCV-envelope antibody responses in a cohort of repeatedly exposed but uninfected subjects. Forty-two hepatitis C diagnostic antibody- and RNA-negative injection drug users at high risk of exposure were studied and findings compared to healthy controls and cases with chronic HCV infection. Purified IgGs from sera were tested by ELISA for binding to genotype 1a and 3a envelope glycoproteins E1E2 with further testing for IgG and IgM reactivity against soluble E2. Virus-neutralizing activity was assessed using an HCV pseudoparticle system. Uninfected subjects demonstrated significantly greater IgG and IgM reactivities to envelope glycoproteins than healthy controls with IgG from 6 individuals additionally showing significant neutralization. This study is the first to describe humoral immunological responses targeting the HCV envelope, important for viral neutralization, in exposed uninfected individuals. A subset of these cases also had evidence of viral neutralization via anti-envelope antibodies. In addition to confirming viral exposure, the presence of specific anti-envelope antibodies may be a factor that helps these individuals resist HCV infection

    Tooling design and microwave curing technologies for the manufacturing of fiber-reinforced polymer composites in aerospace applications

    Get PDF
    The increasing demand for high-performance and quality polymer composite materials has led to international research effort on pursuing advanced tooling design and new processing technologies to satisfy the highly specialized requirements of composite components used in the aerospace industry. This paper reports the problems in the fabrication of advanced composite materials identified through literature survey, and an investigation carried out by the authors about the composite manufacturing status in China’s aerospace industry. Current tooling design technologies use tooling materials which cannot match the thermal expansion coefficient of composite parts, and hardly consider the calibration of tooling surface. Current autoclave curing technologies cannot ensure high accuracy of large composite materials because of the wide range of temperature gradients and long curing cycles. It has been identified that microwave curing has the potential to solve those problems. The proposed technologies for the manufacturing of fiber-reinforced polymer composite materials include the design of tooling using anisotropy composite materials with characteristics for compensating part deformation during forming process, and vacuum-pressure microwave curing technology. Those technologies are mainly for ensuring the high accuracy of anisotropic composite parts in aerospace applications with large size (both in length and thickness) and complex shapes. Experiments have been carried out in this on-going research project and the results have been verified with engineering applications in one of the project collaborating companies

    Population Structure of Humpback Whales from Their Breeding Grounds in the South Atlantic and Indian Oceans

    Get PDF
    Although humpback whales are among the best-studied of the large whales, population boundaries in the Southern Hemisphere (SH) have remained largely untested. We assess population structure of SH humpback whales using 1,527 samples collected from whales at fourteen sampling sites within the Southwestern and Southeastern Atlantic, the Southwestern Indian Ocean, and Northern Indian Ocean (Breeding Stocks A, B, C and X, respectively). Evaluation of mtDNA population structure and migration rates was carried out under different statistical frameworks. Using all genetic evidence, the results suggest significant degrees of population structure between all ocean basins, with the Southwestern and Northern Indian Ocean most differentiated from each other. Effective migration rates were highest between the Southeastern Atlantic and the Southwestern Indian Ocean, followed by rates within the Southeastern Atlantic, and the lowest between the Southwestern and Northern Indian Ocean. At finer scales, very low gene flow was detected between the two neighbouring sub-regions in the Southeastern Atlantic, compared to high gene flow for whales within the Southwestern Indian Ocean. Our genetic results support the current management designations proposed by the International Whaling Commission of Breeding Stocks A, B, C, and X as four strongly structured populations. The population structure patterns found in this study are likely to have been influenced by a combination of long-term maternally directed fidelity of migratory destinations, along with other ecological and oceanographic features in the region

    Genetic Population Structure in the Antarctic Benthos: Insights from the Widespread Amphipod, Orchomenella franklini

    Get PDF
    Currently there is very limited understanding of genetic population structure in the Antarctic benthos. We conducted one of the first studies of microsatellite variation in an Antarctic benthic invertebrate, using the ubiquitous amphipod Orchomenella franklini (Walker, 1903). Seven microsatellite loci were used to assess genetic structure on three spatial scales: sites (100 s of metres), locations (1–10 kilometres) and regions (1000 s of kilometres) sampled in East Antarctica at Casey and Davis stations. Considerable genetic diversity was revealed, which varied between the two regions and also between polluted and unpolluted sites. Genetic differentiation among all populations was highly significant (FST = 0.086, RST = 0.139, p<0.001) consistent with the brooding mode of development in O. franklini. Hierarchical AMOVA revealed that the majority of the genetic subdivision occurred across the largest geographical scale, with Nem≈1 suggesting insufficient gene flow to prevent independent evolution of the two regions, i.e., Casey and Davis are effectively isolated. Isolation by distance was detected at smaller scales and indicates that gene flow in O. franklini occurs primarily through stepping-stone dispersal. Three of the microsatellite loci showed signs of selection, providing evidence that localised adaptation may occur within the Antarctic benthos. These results provide insights into processes of speciation in Antarctic brooders, and will help inform the design of spatial management initiatives recently endorsed for the Antarctic benthos
    • …
    corecore