2,534 research outputs found

    Development of an evaluation technique for strapdown guidance systems Interim report, 1 Feb. 1968 - 1 Feb. 1969

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    Evaluation techniques for astrionics systems using aided strapdown inertial guidanc

    Rivals’ Reactions to Mergers and Acquisitions

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    Mergers and acquisitions research has principally focused on attributes of the acquiring firm and post-acquisition outcomes. To extend our knowledge, we focus on external factors, in particular rival responses, and explore when and how rivals respond to their competitor’s acquisitions. Leveraging the awareness–motivation–capability framework, we predict and find evidence that a rival’s dependence on markets in common with the acquirer, resource similarity between rival and acquirer, and a rival’s organizational slack increase the volume and, in some cases, also the complexity of a rival’s competitive actions following an acquisition. Furthermore, the type of acquisition positively moderates some of these relationships. The results extend our understanding of the influence of mergers and acquisitions on competitive dynamics in the marketplace

    Study of fault-tolerant software technology

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    Presented is an overview of the current state of the art of fault-tolerant software and an analysis of quantitative techniques and models developed to assess its impact. It examines research efforts as well as experience gained from commercial application of these techniques. The paper also addresses the computer architecture and design implications on hardware, operating systems and programming languages (including Ada) of using fault-tolerant software in real-time aerospace applications. It concludes that fault-tolerant software has progressed beyond the pure research state. The paper also finds that, although not perfectly matched, newer architectural and language capabilities provide many of the notations and functions needed to effectively and efficiently implement software fault-tolerance

    PRELIMINARY STUDY: INTERPRETATION OF BARBELL BACK SQUAT KINEMATICS USING PRINCIPAL COMPONENT ANALYSIS

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    The purpose of this study was to reduce the number of kinematic variables of the barbell back squat for easier interpretation by coaches and athletes. Young active adults (N=25) performed the back squat with an intensity of 60%. A total of 10 lower body and trunk measurements were considered for principal components analysis (PCA). Based on the PCA, two components were revealed. The primary component related range of motions (ROMs) in the ankle and knee joints with greater peak flexion angles of ankle, knee, and shank and thigh segments. A secondary component related hip ROMs and hip posterior displacement with greater hip and trunk segment peak flexion angles. Based on this analysis, coaches teaching the barbell back squat should consider two sources of movement variability, one above and one below the hip

    THE EFFECTS OF WEIGHTLIFTING SHOES ON SQUAT KINEMATICS

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    Athletes may not always consider footwear when performing the barbell back squat during training. Several footwear companies have designed shoes claimed to enhance performance in weightlifting and powerlifting. The purpose of this study was to compare the kinematics of the barbell back squat wearing either running shoes (RS) or weightlifting shoes (WLS). Young, healthy active adult males (N=20) were filmed in the sagittal plane while performing barbell back squats for each shoe condition at an intensity of 60% of one repetition maximum (1RM). While a number of kinematic parameters were similar between conditions, the shank maintained a more vertical position and the bar and hip were displaced less when wearing WLS, suggesting a more erect trunk posture. WLS may make small changes that allow for a safer, more effective squat performance

    Ponticulin is the major high affinity link between the plasma membrane and the cortical actin network in Dictyostelium

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    Interactions between the plasma membrane and underlying actin-based cortex have been implicated in membrane organization and stability, the control of cell shape, and various motile processes. To ascertain the function of high affinity actin-membrane associations, we have disrupted by homologous recombination the gene encoding ponticulin, the major high affinity actin-membrane link in Dictyostelium discoideum amoebae. Cells lacking detectable amounts of ponticulin message and protein also are deficient in high affinity actin-membrane binding by several criteria. First, only 10-13% as much endogenous actin cosediments through sucrose and crude plasma membranes from ponticulin-minus cells, as compared with membranes from the parental strain. Second, purified plasma membranes exhibit little or no binding or nucleation of exogenous actin in vitro. Finally, only 10-30% as much endogenous actin partitions with plasma membranes from ponticulin-minus cells after these cells are mechanically unroofed with polylysine-coated coverslips. The loss of the cell\u27s major actin-binding membrane protein appears to be surprisingly benign under laboratory conditions. Ponticulin-minus cells grow normally in axenic culture and pinocytose FITC-dextran at the same rate as do parental cells. The rate of phagocytosis of particles by ponticulin-minus cells in growth media also is unaffected. By contrast, after initiation of development, cells lacking ponticulin aggregate faster than the parental cells. Subsequent morphogenesis proceeds asynchronously, but viable spores can form. These results indicate that ponticulin is not required for cellular translocation, but apparently plays a role in cell patterning during development

    Effectiveness evaluation of STOL transport operations

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    A short-takeoff and landing (STOL) systems simulation model has been developed and implemented in a computer code (known as STOL OPS) which permits evaluation of the operation of a STOL aircraft and its avionics in a commercial airline operating environment. STOL OPS concentrated on the avionics functions of navigation, guidance, control, communication, hazard aviodance, and systems management. External world factors influencing the operation of the STOL aircraft include each airport and its geometry, air traffic at each airport, air traffic control equipment and procedures, weather (including winds and visibility), and the flight path between each airport served by the route. The development of the STOL OPS program provides NASA a set of computer programs which can be used for detailed analysis of a STOL aircraft and its avionics and permit establishment of system requirements as a function of airline mission performance goals

    Problem-based Learning in Institutional and Curricular Design at the New Model Institute for Technology and Engineering (NMITE)

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    NMITE’s Master’s in Integrated Engineering (MEng) was created with a unique philosophy of integrating not only traditionally separate strands of engineering, but also of integrating engineering with other disciplines such as arts, humanities, and business. This broad and deep integration is made possible by adopting the principles and practices of problem-based learning (PBL) and embedding them within predetermined module challenges. In this way, each PBL challenge highlights and hones areas of engineering expertise and embeds liberal subjects whilst maintaining the integration intrinsic to the programme. Overall, this method supports the use of block learning with deep integration of employers and the community in the educational experience
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