1,859 research outputs found
Video photographic considerations for measuring the proximity of a probe aircraft with a smoke seeded trailing vortex
Considerations for acquiring and analyzing 30 Hz video frames from charge coupled device (CCD) cameras mounted in the wing tips of a Beech T-34 aircraft are described. Particular attention is given to the characterization and correction of optical distortions inherent in the data
Mode shape analysis using a commercially available peak store video frame buffer
Time exposure photography, sometimes coupled with strobe illumination, is an accepted method for motion analysis that bypasses frame by frame analysis and resynthesis of data. Garden variety video cameras can now exploit this technique using a unique frame buffer that is a non-integrating memory that compares incoming data with that already stored. The device continuously outputs an analog video signal of the stored contents which can then be redigitized and analyzed using conventional equipment. Historically, photographic time exposures have been used to record the displacement envelope of harmonically oscillating structures to show mode shape. Mode shape analysis is crucial, for example, in aeroelastic testing of wind tunnel models. Aerodynamic, inertial, and elastic forces can couple together leading to catastrophic failure of a poorly designed aircraft. This paper will explore the usefulness of the peak store device as a videometric tool and in particular discuss methods for analyzing a targeted vibrating plate using the 'peak store' in conjunction with calibration methods familiar to the close-range videometry community. Results for the first three normal modes will be presented
The Stockholm Paradigm: Lessons for the Emerging Infectious Disease Crisis
The emerging infectious disease (EID) crisis represents an immediate existential threat to modern humanity. Current policies aimed at coping with the EID crisis are ineffective and unsustainably expensive. They have failed because they are based on a scientific paradigm that produced the parasite paradox. The Stockholm paradigm (SP) resolves the paradox by integrating four elements of evolutionary biology: ecological fitting, sloppy fitness space, coevolution, and responses to environmental perturbations. It explains why and how the EID crisis occurs and is expanding and what happens after an EID emerges that sets the stage for future EIDs. The SP provides a number of critical insights for changing scientific and public policy in a manner that allows us to begin coping with the EID crisis in an effective manner. It provides hope that we can anticipate EIDs and prevent them or at least mitigate their impacts.
This article has been produced in support of and with appreciation for the efforts by GĂĄbor FöldvĂĄri of the Institute of Evolution, Centre for Ecological Research, and the Centre for Eco-Epidemiology, National Laboratory for Health Security (both located at 1121 Budapest, Konkoly-Thege MiklĂłs Ășt 29-33, Hungary). Through his untiring efforts, team building, and leadership, he has secured the first EU-wide team research grant. This work was supported by the National Research, Development and Innovation Office in Hungary (RRF-2.3.1-21-2022-00006) and the COST Action CA21170 âPrevention, anticipation and mitigation of tick-borne disease risk applying the DAMA protocol (PRAGMATICK),â which represent the first funded efforts to apply the principles of the DAMA protocol
Stepping-stones and Mediators of Pandemic ExpansionâA Context for Humans as Ecological Super-spreaders
Humans represent ecological super-spreaders in the dissemination and introduction of pathogens. These processes, consistent with the dynamics of the Stockholm paradigm, are exemplified in the origin and globalized distributions of SARS-CoV-2 since initial recognition in central Asia during 2019 and 2020. SARS-like viruses are not widespread in mammals but appear widespread in chiropterans. Bats are isolated ecologically from most other assemblages of mammals in terrestrial systems. Humans may be the stepping-stone hosts for broad global dissemination and wider infection (given the opportunity) among diverse assemblages of mammals in which host and viral capacity are compatible. Human globalization mediated insertion in global ecosystems along primary and secondary pathways initially with localized to regional circulation across continents. Origins and persistence of cycles involving variants and viral transmission among other mammals and the potential for secondary exposure (retrocolonization) of people occurs on multidirectional pathways. Humans were responsible for the initial breakdown in ecological isolation of the virus that facilitated colonization events from chiropterans to other mammals. In the absence of these human drivers, environmental or ecological interfaces (boundary zones among habitats) limiting the distribution of SARS-CoV-2 are unlikely to have been crossed, leaving a diverse assemblage of SARS-like viruses (Sarbecovirus) remaining relatively hidden and isolated in southeast Asia
Knowing the Biosphere: Documentation, Specimens, Archives, and Names Reveal Environmental Change and Emerging Pathogens
One Health programs and trajectories are now the apparent standard for exploring the occurrence and distribution of emerging pathogens and disease. By definition, One Health has been characterized as a broadly inclusive, collaborative, and transdisciplinary approach with connectivity across local to global scales, which integrates the medical and veterinary community to recognize health outcomes emerging at the environmental nexus for people, animals, plants, and their shared landscapes. One Health has been an incomplete model, conceptually and operationally, focused on reactive and response-based foundations, to limit the impact of emerging pathogens and emerging infectious diseases and, as such, lacks a powerful proactive capacity. A proactive, predictive One Health is necessary, emanating in part from geographically/taxonomically broad and temporally deep biological collections of pathogen-host assemblages. The DAMA protocol (Document, Assess, Monitor, Act), the operational extension of the Stockholm paradigm (SP), accomplishes this task by encompassing holistic and strategic biological sampling of reservoir host assemblages and pathogens at environmental interfaces and more extensively through resurveys, with development of informatics resources digitally linked to physical specimens held in publicly accessible museum biorepositories. Archives of specimens are the foundations for accumulating interrelated archives of information (the baselines against which change can be identified and tracked), with collections serving as fundamental resources for biodiversity informatics under the conceptual evolutionary and ecological umbrella of the SP. A cultural and conceptual transformation is essential among the diverse practitioners in the One Health community, one that recognizes the necessity of placing pathogens in an evolutionary, ecological, and environmental context by integrating specimens and associated informatics into an infrastructure and networks for actionable information. As a community, it is essential to abandon response-based business as usual while looking forward toward proactive transboundary approaches that maximize our conceptual and taxonomic view of diversity across interconnected planetary scales that influence the complexity of pathogen-host interfaces. Evolution, where the past always influences the present and the future, defines our trajectory, as the need for sustained archives that describe the biosphere becomes more acute with each passing day
Protein dynamics with off-lattice Monte Carlo moves
A Monte Carlo method for dynamics simulation of all-atom protein models is
introduced, to reach long times not accessible to conventional molecular
dynamics. The considered degrees of freedom are the dihedrals at
C-atoms. Two Monte Carlo moves are used: single rotations about
torsion axes, and cooperative rotations in windows of amide planes, changing
the conformation globally and locally, respectively. For local moves Jacobians
are used to obtain an unbiased distribution of dihedrals. A molecular dynamics
energy function adapted to the protein model is employed. A polypeptide is
folded into native-like structures by local but not by global moves.Comment: 10 pages, 4 Postscript figures, uses epsf.sty and a4.sty; scheduled
tentatively for Phys.Rev.E issue of 1 March 199
The DAMA Protocol, an Introduction: Finding Pathogens before They Find Us
Globally, humanity is coming to recognize the magnitude of the interactive crisis for emerging infectious disease (EID). Strategies for coping with EID have been largely in the form of reactive measures for crisis response. The DAMA protocol (Document, Assess, Monitor, Act), the operational policy extension of the Stockholm paradigm, constitutes a preventive/proactive dimension to those efforts. DAMA is aimed at focusing and extending human and material resources devoted to coping with the accelerating wave of EID. DAMA is integrative, combining efforts to strategically document the distribution of complex pathogen and host assemblages in the biosphere in the context of dynamic environmental interfaces that provide the opportunities for pathogen exchange and emergence. Movement of habitats and animals (a breakdown in ecological isolation) catalyzed by climate change and broader anthropogenic trajectories of environmental disruption provide the landscape of opportunity for emergence. Evolutionarily and ecologically conserved capacities for exploitation of host-based resources allow pathogens to persist in one place or among a particular spectrum of hosts and provide insights to predict outcomes of persistence and emergence in novel conditions and across changing ecological interfaces. DAMA trajectories combine âboots on the groundâ contributions of citizen scientists working with field biologists in development and application of sophisticated archival repositories, bioinformatics, molecular biology, and satellite surveillance. DAMA is a focus for anticipation, mitigation, and prevention of EID through knowledge of pathogens present in the environment and actions necessary to diminish risk space for their emergence. DAMA can be an effective strategy for buying time in the arena of accelerating environmental and socioeconomic disturbance and expanding EID linked to a future of climate change. Information + action = prediction and lives saved in a realm of EID.
This article has been produced in support of and with appreciation for the efforts by GĂĄbor FöldvĂĄri of the Institute of Evolution, Centre for Ecological Research, and the Centre for Eco-Epidemiology, National Laboratory for Health Security (both located at 1121 Budapest, Konkoly-Thege MiklĂłs Ășt 29-33, Hungary). Through his untiring efforts, team building, and leadership, he has secured the first EU-wide team research grant. This work was supported by the National Research, Development and Innovation Office in Hungary (RRF-2.3.1-21-2022-00006) and the COST Action CA21170 âPrevention, anticipation and mitigation of tick-borne disease risk applying the DAMA protocol (PRAGMATICK),â which represent the first funded efforts to apply the principles of the DAMA protocol
Before the Pandemic Ends: Making Sure This Never Happens Again
Introduction
On 30 January 2020, the World Health Organization (WHO) declared a Global Health Emergency of international concern attendant to the emergence and spread of SARS-CoV-2, nearly two months after the first reported emergence of human cases in Wuhan, China. In the subsequent two months, global, national and local health personnel and infrastructures have been overwhelmed, leading to suffering and death for infected people, and the threat of socio-economic instability and potential collapse for humanity as a whole. This shows that our current and traditional mode of coping, anchored in responses after the fact, is not capable of dealing with the crisis of emerging infectious disease. Given all of our technological expertise, why is there an emerging disease crisis, and why are we losing the battle to contain and diminish emerging diseases?
Part of the reason is that the prevailing paradigm explaining the biology of pathogen-host associations (coevolution, evolutionary arms races) has assumed that pathogens must evolve new capacities - special mutations â in order to colonize new hosts and produce emergent disease (e.g. Parrish and Kawaoka, 2005). In this erroneous but broadly prevalent view, the evolution of new capacities creates new opportunities for pathogens. Further, given that mutations are both rare and undirected, the highly specialized nature of pathogen-host relationships should produce an evolutionary firewall limiting dissemination; by those definitions, emergences should be rare (for a historical review see Brooks et al., 2019). Pathogens, however, have become far better at finding us than our traditional understanding predicts. We face considerable risk space for pathogens and disease that directly threaten us, our crops and livestock â through expanding interfaces bringing pathogens and hosts into increasing proximity, exacerbated by environmental disruption and urban density, fueled by globalized trade and travel. We need a new paradigm that explains what we are seeing.
Additional section headers:
The Stockholm Paradigm
The DAMA Protocol
A Sense of Urgency and Long-Term Commitment
Reference
High-resolution mass models of dwarf galaxies from LITTLE THINGS
We present high-resolution rotation curves and mass models of 26 dwarf galaxies from LITTLE THINGS. LITTLE THINGS is a high-resolution Very Large Array HI survey for nearby dwarf galaxies in the local volume within 11 Mpc. The rotation curves of the sample galaxies derived in a homogeneous and consistent manner are combined with Spitzer archival 3.6 micron and ancillary optical U, B, and V images to construct mass models of the galaxies. We decompose the rotation curves in terms of the dynamical contributions by baryons and dark matter halos, and compare the latter with those of dwarf galaxies from THINGS as well as Lambda CDM SPH simulations in which the effect of baryonic feedback processes is included. Being generally consistent with THINGS and simulated dwarf galaxies, most of the LITTLE THINGS sample galaxies show a linear increase of the rotation curve in their inner regions, which gives shallower logarithmic inner slopes alpha of their dark matter density profiles. The mean value of the slopes of the 26 LITTLE THINGS dwarf galaxies is alpha =-0.32 +/- 0.24 which is in accordance with the previous results found for low surface brightness galaxies (alpha = -0.2 +/- 0.2) as well as the seven THINGS dwarf galaxies (alpha =-0.29 +/- 0.07). However, this significantly deviates from the cusp-like dark matter distribution predicted by dark-matter-only Lambda CDM simulations. Instead our results are more in line with the shallower slopes found in the Lambda CDM SPH simulations of dwarf galaxies in which the effect of baryonic feedback processes is included. In addition, we discuss the central dark matter distribution of DDO 210 whose stellar mass is relatively low in our sample to examine the scenario of inefficient supernova feedback in low mass dwarf galaxies predicted from recent Lambda SPH simulations of dwarf galaxies where central cusps still remain.Peer reviewe
Anomalous low-temperature and high-field magnetoresistance in the organic superconductor ÎČâł-(BEDT-TTF)2SF5CH2CF2SO3
We report direct observations of anomalous magnetic-field and temperature dependences of the Shubnikovâde Haas oscillations in the organic superconductor ÎČâł-(BEDT-TTF)âSFâ
CHâCFâSOâ. Unlike other BEDT-TTF based organic superconductors, a nonmetallic temperature dependence of the background magnetoresistance is clearly observed. It is speculated that the nonmetallic behavior may arise from a partial nesting of the open orbits, similar to the field-induced density wave in the quasi-one-dimensional systems or a charge localization. The analysis of the magnetoresistance oscillations are found to deviate from the conventional Lifshitz-Kosevich description at high field and low temperatures. [S0163-1829(99)05433-8
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