111 research outputs found

    Sonar-induced pressure fields in a post-mortem common dolphin

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    Author Posting. © Acoustical Society of America, 2012. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 131 (2012): 1595-1604, doi:10.1121/1.3675005.Potential physical effects of sonar transmissions on marine mammals were investigated by measuring pressure fields induced in a 119-kg, 211-cm-long, young adult male common dolphin (Delphinus delphis) cadaver. The specimen was instrumented with tourmaline acoustic pressure gauges used as receiving sensors. Gauge implantation near critical tissues was guided by intraoperative, high-resolution, computerized tomography (CT) scanning. Instrumented structures included the melon, nares, ear, thoracic wall, lungs, epaxial muscle, and lower abdomen. The specimen was suspended from a frame equipped with a standard 50.8-mm-diameter spherical transducer used as the acoustic source and additional receiving sensors to monitor the transmitted and external, scattered field. Following immersion, the transducer transmitted pulsed sinusoidal signals at 5, 7, and 10 kHz. Quantitative internal pressure fields are reported for all cases except those in which the gauge failed or no received signal was detected. A full necropsy was performed immediately after the experiment to examine instrumented areas and all major organs. No lesions attributable to acoustic transmissions were found, consistent with the low source level and source-receiver distances.Work supported by NOPP through ONR Grant No. N000140710992. Work at CSI additionally supported by ONR Grant No. N000140811231

    Plasma Components Affect Accuracy of Circulating Cancer-Related MicroRNA Quantitation

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    Circulating microRNAs (miRNAs) have emerged as candidate biomarkers of various diseases and conditions including malignancy and pregnancy. This approach requires sensitive and accurate quantitation of miRNA concentrations in body fluids. Herein we report that enzyme-based miRNA quantitation, which is currently the mainstream approach for identifying differences in miRNA abundance among samples, is skewed by endogenous serum factors that co-purify with miRNAs and anticoagulant agents used during collection. Of importance, different miRNAs were affected to varying extent among patient samples. By developing measures to overcome these interfering activities, we increased the accuracy, and improved the sensitivity of miRNA detection up to 30-fold. Overall, the present study outlines key factors that prevent accurate miRNA quantitation in body fluids and provides approaches that enable faithful quantitation of miRNA abundance in body fluids

    Plasma Dynamics

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    Contains reports on seventeen research projects split into two sections.National Science Foundation (Grant ENG77-00340)U. S. Energy Research and Development Administration (Contract E(11-1)-2766)U. S. Energy Research and Development Administration (Contract EY-76-S-02-2766)U. S. Air Force - Office of Scientific Research (Grant AFOSR-77-3143)U. S. Department of Energy (Grant EG-77-G-01-4107

    Connectivity and systemic resilience of the Great Barrier Reef

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    Australia’s iconic Great Barrier Reef (GBR) continues to suffer from repeated impacts of cyclones, coral bleaching, and outbreaks of the coral-eating crown-of-thorns starfish (COTS), losing much of its coral cover in the process. This raises the question of the ecosystem’s systemic resilience and its ability to rebound after large-scale population loss. Here, we reveal that around 100 reefs of the GBR, or around 3%, have the ideal properties to facilitate recovery of disturbed areas, thereby imparting a level of systemic resilience and aiding its continued recovery. These reefs (1) are highly connected by ocean currents to the wider reef network, (2) have a relatively low risk of exposure to disturbances so that they are likely to provide replenishment when other reefs are depleted, and (3) have an ability to promote recovery of desirable species but are unlikely to either experience or spread COTS outbreaks. The great replenishment potential of these ‘robust source reefs’, which may supply 47% of the ecosystem in a single dispersal event, emerges from the interaction between oceanographic conditions and geographic location, a process that is likely to be repeated in other reef systems. Such natural resilience of reef systems will become increasingly important as the frequency of disturbances accelerates under climate change

    The return of the fifties: Trends in college students' values between 1952 and 1984

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    Five identical surveys were carried out in 1952, 1968–1969, 1974, 1979, and 1984 among undergraduate men at Dartmouth College and the University of Michigan to measure value trends. In most value domains the trends are U-shaped, showing that the trends from the fifties to the sixties and seventies have reversed, and attitudes in 1984 were either similar to the fifties or moving in that direction. The domains include traditional religion, career choice, faith in government and the military, advocacy of social constraints on deviant social groups, attitudes about free enterprise, government and economics, sexual morality, marijuana use, and personal moral obligations. Two attitude areas do not show a return of the fifties: (1) other-direction was high in 1952, then dropped to the sixties and did not rise; (2) the level of politicization rose greatly from 1952 to the sixties, then dropped again only slightly.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45659/1/11206_2005_Article_BF01106623.pd

    Existing Infection Facilitates Establishment and Density of Malaria Parasites in Their Mosquito Vector

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    Very little is known about how vector-borne pathogens interact within their vector and how this impacts transmission. Here we show that mosquitoes can accumulate mixed strain malaria infections after feeding on multiple hosts. We found that parasites have a greater chance of establishing and reach higher densities if another strain is already present in a mosquito. Mixed infections contained more parasites but these larger populations did not have a detectable impact on vector survival. Together these results suggest that mosquitoes taking multiple infective bites may disproportionally contribute to malaria transmission. This will increase rates of mixed infections in vertebrate hosts, with implications for the evolution of parasite virulence and the spread of drug-resistant strains. Moreover, control measures that reduce parasite prevalence in vertebrate hosts will reduce the likelihood of mosquitoes taking multiple infective feeds, and thus disproportionally reduce transmission. More generally, our study shows that the types of strain interactions detected in vertebrate hosts cannot necessarily be extrapolated to vectors
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