915 research outputs found

    A Century Old Problem: Federal Or State Law As Determinative Of A Directed Verdict In A Federal Court

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    The laws of the several states, except where the Constitution or Treaties of the United States or Acts of Congress otherwise require or provide, shall be regarded as rules of decision in civil actions in the courts of the United States, in cases where they apply. \u27 So states the commandment by the Congress of the United States which gov- erns the applicability of state law in all federal civil actions wherein jurisdiction is founded upon diversity of citizenship

    Overview of the Tevatron Collider Complex: Goals, Operations and Performance

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    For more than two decades the Tevatron proton-antiproton collider was the centerpiece of the world's high energy physics program. The collider was arguably one of the most complex research instruments ever to reach the operation stage and is widely recognized for numerous physics discoveries and for many technological breakthroughs. In this article we outline the historical background that led to the construction of the Tevatron Collider, the strategy applied to evolution of performance goals over the Tevatron's operational history, and briefly describe operations of each accelerator in the chain and achieved performance.Comment: Includes modifications suggested by reviewer

    The future of pediatric pulmonology: A survey of division directors, assessment of current research funding, and discussion of workforce trends

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    Adequacy of the US workforce in pediatric pulmonology has been a source of serious concern within the field for some time, as it has been for several pediatric subspecialties. Contributing factors have been thought to include low fill rates of fellowship training programs, aging, and retirement rates of the subspecialist population, and the perception of insufficient numbers of specialists in some regions to meet clinical care needs. Several approaches to assessing workforce needs have already been described, and stakeholder groups are currently working on additional analyses. Although the recent report by Harris et al. captured a broad snapshot of workforce perceptions of 485 pediatric pulmonologists, this study (reporting data collected in 2014) did not address the future scope of practice

    The diffusion of IP telephony and vendors' commercialisation strategies

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    This is a post-peer-review, pre-copyedit version of an article published in the Journal of Information Technology. The definitive publisher-authenticated version is available at the link below.The Internet telephony (IP telephony) has been presented as a technology that can replace existing fixed-line services and disrupt the telecommunications industry by offering new low-priced services. This study investigates the diffusion of IP telephony in Denmark by focusing on vendors’ commercialisation strategies. The theory of disruptive innovation is introduced to investigate vendors’ perceptions about IP telephony and explore their strategies that affect the diffusion process in the residential market. The analysis is based on interview data collected from the key market players. The study's findings suggest that IP telephony is treated as a sustaining innovation that goes beyond the typical voice transmission and enables provision of advanced services such as video telephony

    The effect of sand fencing on the morphology of natural dune systems

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    Sand fences are a frequently used management tool on developed coastlines because they are inexpensive and easy to install. While the geomorphic effect of sand fences has been investigated before, previous studies have been limited in both temporal and spatial domains. Here, we present the evolution of Bogue Banks, a developed barrier island along the Outer Banks of North Carolina, over a 20-year period from 1997 to 2016 where sand fences were emplaced along parts of the island in 2010. We use LiDAR-derived cross-shore transects (n = 38,454) to measure beach and foredune features along the extent (~40 km) of Bogue Banks for every available year of lidar data as well as the locations of sand fences, which we identify in 39% of the transects following fence construction. First, we found that vertical growth of the natural foredunes along Bogue Banks was slightly positive between 2010 and 2016 despite an increased amount of shoreline erosion. This pattern was coincident with a combination of sand fence installation and beach nourishment efforts, which were most heavily focused on the eastern end of the island. Second, we found that natural foredunes located behind fenced dunes are typically shorter, wider, and smaller in volume than natural foredunes in non-fenced and undeveloped areas. Although this may partly be due to a tendency for fences to be installed in front of more vulnerable dunes, our results suggest that, once emplaced, sand fences prevent growth of the landward foredune behind fenced dunes. These findings suggest that sand fences block sediment supply to landward dunes, leading to a shorter and wider complex foredune than would otherwise naturally occur

    Isolation, identification and genetic characterisation of a microsporidium isolated from carob moth, Ectomyelois ceratoniae (Zeller) (Lepidoptera: Pyralidae)

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    'Microsporidia' is a term used for organisms belonging to the phylum Microspora, which contains approximately 187 genera and 1500 species (Corradi 2015). They are obligate intracellular parasites with no active metabolic stages of the life cycle occurring outside of the host cells (Franzen & Muller 1999; Garcia 2002; Tsai et al. 2003; Huang et al. 2004). They exhibit eukaryotic characteristics such as a membrane-bound nucleus, an intracytoplasmic membrane system, and chromosome separation occurs on mitotic spindles. However, they also exhibit prokaryotic characteristics such as possession of a 70S ribosome, lack of true mitochondria and peroxisomes, a simple version of the Golgi apparatus, and a small genome which is much less complex than those of most eukaryotes (Franzen & Muller 1999; Garcia 2002). Microspo- ridia are parasitic in all major groups of animals, both vertebrates and invertebrates (Sprague 1977; Franzen & Muller 1999). Microsporidia were first recognised as pathogens in silkworms by Nageli (1857), and now have been found to infect many hosts such as humans, insects, fish and mammals (Stentiford et al. 2016)

    The relative role of constructive and destructive processes in dune evolution on Cape Lookout National Seashore, North Carolina, USA

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    Coastal dunes are dynamic features that are continuously evolving due to constructive (e.g., wind- and wave-driven sediment transport) and destructive (e.g., elevated total water levels during storm events) processes. However, the relative importance of these processes in determining dune evolution is often poorly understood. In this study, ten lidar datasets from 1997 to 2016 are used to determine the relative role of erosion and accretion processes driving foredune change on the coast of Cape Lookout National Seashore, North Carolina, USA. Beach and dune morphometrics reveal that dune toe locations have generally retreated since 1997, while dune crest heights accreted by 0.01–0.02 m/year. We develop three univariate metrics that represent (1) the potential for erosion, i.e., total water level impact hours per year, (2) accretion, i.e., dune building hours per year, and (3) the relative net effect of foredune accretion and erosion processes, i.e., constructive–destructive dune forcing (CDDF) ratio, and test the correlative power of these metrics in explaining changes in foredune morphology. The total water level impact hours per year metric explained as much as 66% and 67% of the variance in dune crest and toe elevations, respectively, across the nearly two decades of dune evolution. The greatest number of dune building hours per year and largest dunes within the study site co-occurred at locations exposed to the dominant cross-shore wind direction as a result of varying shoreline orientation. The CDDF ratio was positively correlated to changes in the dune toe elevation in approximately 70% of dunes within the study site, outperforming the impact and dune building hours per year metrics. Our results show that these three metrics can provide first-order estimates of dune morphometric change across multiple spatial and temporal scales, which may be particularly useful at sites where lidar acquisition is intermittent

    The relative influence of dune aspect ratio and beach width on dune erosion as a function of storm duration and surge level

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    Dune height is an important predictor of impact during a storm event given that taller dunes have a lower likelihood of being overtopped than shorter dunes. However, the temporal dominance of the wave collision regime, wherein volume loss (erosion) from the dune occurs through dune retreat without overtopping, suggests that dune width must also be considered when evaluating the vulnerability of dunes to erosion. We use XBeach, a numerical model that simulates hydrodynamic processes, sediment transport, and morphologic change, to analyze storm-induced dune erosion as a function of dune aspect ratio (i.e., dune height versus dune width) for storms of varying intensity and duration. We find that low aspect ratio (low and wide) dunes lose less volume than high aspect ratio (tall and narrow) dunes during longer and more intense storms when the beach width is controlled for. In managed dune scenarios, where sand fences are used to construct a "fenced"dune seaward of the existing "natural"dune, we find that fenced dunes effectively prevent the natural dune behind them from experiencing any volume loss until the fenced dune is sufficiently eroded, reducing the magnitude of erosion of the natural dune by up to 50ĝ€¯%. We then control for dune morphology to assess volume loss as a function of beach width and confirm that beach width exerts a significant influence on dune erosion; a wide beach offers the greatest protection from erosion in all circumstances while the width of the dune determines how long the dune will last under persistent scarping. These findings suggest that efforts to maintain a wide beach may be effective at protecting coastal communities from dune loss. However, a trade-off may exist in maintaining wide beaches and dunes in that the protection offered in the short-term must be considered in concert with potentially long-term detrimental effects of limiting overwash, a process which is critical to maintaining island elevation as sea level rises

    Synchronous pumping of an optical parametric oscillator using an amplified quasi-cw pump envelope

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    Pulse-slicing from a cw laser output followed by high gain amplification can produce quasi-cw pulses at power levels well in excess of those available from large frame cw lasers. Mode-locked pulse trains with an envelope of 10”s duration and at 2kHz repetition rate are amplified by a factor of 20 to give 5 Watts of envelope average power. These power levels allow efficient single-pass frequency doubling and subsequent pumping of a lithium triborate optical parametric oscillator
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