Simulated impacts of anthropogenic land-cover change on the mesoscale climate of the Florida peninsula

Fall 2004.Also issued as author's dissertation (Ph.D.) -- Colorado State University, 2004.Includes bibliographical references.Datasets representing both natural and current land cover on the Florida peninsula were implemented in the Regional Atmospheric Modeling System to simulate the impacts of anthropogenic land-cover change on the mesoscale climate of the region. Implementation of current land cover in simulations of three recent July-August periods resulted in generally increased daily maximum temperature, especially along an interior north-to-south axis corresponding to natural wetlands within the Kissimmee River basin and south of Lake Okeechobee that were drained during the 20th Century. In the natural land-cover case, this axis was associated with a local minimum in sensible heat flux, which served to generate a horizontally divergent mesoscale wind that reinforced the convergence along the adjacent sea-breeze fronts. This feature was diminished or altogether absent in the simulations with current land cover, because those wetlands were largely drained during the 20th Century. As a result, the simulated convergence along the adjacent sea-breeze fronts was weakened, and the divergence along the interior axis was diminished. This mechanism resulted in decreased rainfall along the sea-breeze fronts and increases along the interior axis. When expressed as an average over the model domain, the convective rainfall was decreased 10-12% from the natural case total. These results provide evidence of a physical-dynamical mechanism that links the mesoscale spatial distributions of the changes in land cover, surface fluxes, the sea-breeze circulations, and convective rainfall with a regional-scale decrease in warm season rainfall. These results were consistent when subjected to a variety of model sensitivity tests. The differences in grid-average rainfall and daily maximum temperature are also consistent with long-term trends derived from an analysis of observational data. The two land-cover datasets were also applied to simulate three recent (and climatologically rare) damaging freeze events in south Florida. In most areas of the model domain where wetlands were drained and converted to agriculture during the 20th Century, minimum temperatures were colder when current land cover was implemented. Further examination of one event reveals that if wetlands were specified, the resulting increased heat capacity of the surface and a persistent water vapor flux acted to diminish the cooling rate of the lower atmosphere, thereby altogether preventing the development of freezing conditions at a location where crop losses totaled US $300M. With current land cover (agriculture), subfreezing temperatures developed and persisted for five hours. The results presented in this work suggest that anthropogenic land-cover changes have significantly impacted several aspects of the mesoscale climate of the Florida Peninsula. The results of this study also support previous studies in concluding that perturbations introduced to the climate system through anthropogenic land-cover change are physically and socioeconomically significant.Sponsored by USGS grant no. 1434-CR-97-AG-00025, task 7 and NASA grant no. NAG5-11370

Device-Independent Quantum Key Distribution with Generalized Two-Mode Schrödinger Cat States

We show how weak nonlinearities can be used in a device-independent quantum key distribution (QKD) protocol using generalized two-mode Schrödinger cat states. The QKD protocol is therefore shown to be secure against collective attacks and for some coherent attacks. We derive analytical formulas for the optimal values of the Bell parameter, the quantum bit error rate, and the device-independent secret key rate in the noiseless lossy bosonic channel. Additionally, we give the filters and measurements which achieve these optimal values. We find that, over any distance in this channel, the quantum bit error rate is identically zero, in principle, and the states in the protocol are always able to violate a Bell inequality. The protocol is found to be superior in some regimes to a device-independent QKD protocol based on polarization entangled states in a depolarizing channel. Finally, we propose an implementation for the optimal filters and measurements

Magnetic Polarity Stratigraphy and \u3csup\u3e40\u3c/sup\u3eK-\u3csup\u3e40\u3c/sup\u3eAR Dating of Late Miocene and Early Pliocene Continental Deposits, Catamarca Province, NW Argentina

Magnetostratigraphic and 40K-40Ar data on a 2300 m thick sequence of continental sediments at Puerta de Corral Quemado in Catamarca Province, NW Argentina permit calibration of land mammal faunas of late Tertiary (Huayquerian and Montehermosan) age. The sequence represents (from oldest to youngest) the Chiquimil A, Araucanense, and Corral Quemado Formations. Paleomagnetic samples were collected from 99 stratigraphic levels. Strong-field thermomagnetic and isothermal remanent magnetization experiments indicate that the dominant ferrimagnetic mineral is magnetite. Progressive alternating-field (AF) and themal demagnetization of the natural remanent magnetism (NRM) demonstrates that AF demagnetization to 20 mT peak field is sufficient to isolate the primary NRM which is of depositional origin. The resulting paleomagnetic data provide a well-defined magnetic polarity zonation, although sampling is less dense in the upper half of the section. 40K-40Ar data obtained from mineral separates of four tuffs within the section allow reliable age determinations for those levels. The combined magnetostratigraphic and 40K-40Ar data allow the magnetic polarity zonation to be correlated with the magnetic polarity time scale. This correlation indicates a nearly constant rate of sediment accumulation between ~8.0 Ma and 3.5 Ma. The boundary between the Araucanense and Corral Quemado Formations approximates the boundary between the Huayquerian and Montehermosan land mammal age faunas at this locality. The data presented here allow the boundary between the Araucanense and Corral Quemado Formations to be dated at 6.4 Ma. Combined with geochronologic data from similar age rocks and faunas from San Carlos, Mendoza Province, west-central Argentina, the geochronologic data from Puerta de Corral Quemado allow the Huayquerian-Monteher-mosan land mammal age boundary to be placed tentatively at 6.0 Ma. A specimen of the fossil land mammal Cyonasua (family Procyonidae) from unit 14 of the Araucanense Formation is dated at 7.0 to 7.5 Ma. This specimen is the earliest known representative of this North American group in South America and represents the oldest dated participant in the Great American Faunal Interchange on that continent

Facilitating children’s contributions in clinic? Findings from an in-depth qualitative study with children with type 1 diabetes

Aims: There is a policy drive for children to contribute more directly in clinic visits. However, this has yet to be routinely achieved in practice and relatively little is known to date about younger children’s views of their illness and care. This in-depth qualitative study set out to explore the experiences of children 10 years or younger living with Type 1 diabetes. Methods: The sample of 17 children was self-selecting from a population of 140 children under 11 years receiving treatment for Type 1 diabetes at two outpatient clinics in a large, multicultural city. Fieldwork comprised home visits, discussion groups and observation in outpatient clinics. Results: Children’s strong experiential understandings of their condition, the impact of their social position on experiences of care and their active role in maintenance of the regimen were at odds with how they were positioned, and how the disease was discussed, in clinic. Conclusion: Findings have implications for facilitating children’s contributions in clinic, understanding how ideas about children are reproduced in clinical settings and supporting clinicians to engage with the capacities and priorities of children living with long-term illness

Chronic viral infection promotes sustained Th1-derived immunoregulatory IL-10 via BLIMP-1

During the course of many chronic viral infections, the antiviral T cell response becomes attenuated through a process that is regulated in part by the host. While elevated expression of the immunosuppressive cytokine IL-10 is involved in the suppression of viral-specific T cell responses, the relevant cellular sources of IL-10, as well as the pathways responsible for IL-10 induction, remain unclear. In this study, we traced IL-10 production over the course of chronic lymphocytic choriomeningitis virus (LCMV) infection in an IL-10 reporter mouse line. Using this model, we demonstrated that virus-specific T cells with reduced inflammatory function, particularly Th1 cells, display elevated and sustained IL-10 expression during chronic LCMV infection. Furthermore, ablation of IL-10 from the T cell compartment partially restored T cell function and reduced viral loads in LCMV-infected animals. We found that viral persistence is needed for sustained IL-10 production by Th1 cells and that the transcription factor BLIMP-1 is required for IL-10 expression by Th1 cells. Restimulation of Th1 cells from LCMV-infected mice promoted BLIMP-1 and subsequent IL-10 expression, suggesting that constant antigen exposure likely induces the BLIMP-1/IL-10 pathway during chronic viral infection. Together, these data indicate that effector T cells self-limit their responsiveness during persistent viral infection via an IL-10-dependent negative feedback loop.This work was supported by an Australian NHMRC Overseas Biomedical Postdoctoral Fellowship (to I.A. Parish); a Yale School of Medicine Brown-Coxe Postdoctoral Fellowship (to I.A. Parish); the Alexander von Humboldt Foundation (SKA2010, to P.A. Lang); a CIHR grant (to P.S. Ohashi); and by the Howard Hughes Medical Institute and NIH grant RO1AI074699 (to S.M. Kaech). P.S. Ohashi holds a Canada Research Chair in Autoimmunity and Tumor immunity

Applying experimental micro-tool wear measurement techniques to industrial environments

Productivity in micro-milling is hindered by premature fracture of tools and difficulty predicting wear. This work builds upon previous investigations into tool wear mechanisms and coatings for micro-mills.The technology readiness level of this work exceeds previous studies by investigating the micro-mills for practical applications and comparing this data. 0.5 mm micro end mills are tested with different coatings on CuZn38, and wear curves produced both in the case of simple straight slot testing and milling of complex parts representing industrial applications. The results show that curves produced using straight slots can be used to predict the behaviour of tools used to machine industrial parts. Due to interrupted cutting, tools used in straight slot tests reach the end of steady state wear after approximately 12 s of cutting as compared with 170 s in continuous milling. Typical cutting forces seen for the tools are in the order of 2–4 N. Catastrophic failure is seen towards the end of tool life for a TiAlN tool with a cutting force of over 30 N seen. For the first time a comparison has been made between fundamental tool wear studies and tool wear observed when producing test pieces representative to micro-industrial parts. This presents a novel perspective on tool wear and facilitates the integrating of existing micro-milling research into industr

A Magnetohydrodynamic Model of the M87 Jet I: Superluminal Knot Ejections from HST-1 as Trails of Quad Relativistic MHD Shocks

This is the first in a series of papers that introduces a new paradigm for understanding the jet in M87: a collimated relativistic flow in which strong magnetic fields play a dominant dynamical role. Here wefocus on the flow downstream of HST-1 - an essentially stationary flaring feature that ejects trails of superluminal components. We propose that these components are quad relativistic magnetohydrodynamic shock fronts (forward/reverse fast and slow modes) in a narrow jet with a helically twisted magnetic structure. And we demonstrate the properties of such shocks with simple one-dimensional numerical simulations. Quasi-periodic ejections of similar component trails may be responsible for the M87 jet substructures observed further downstream on 100 - 1,000 pc scales. This new paradigm requires the assimilation of some new concepts into the astrophysical jet community, particularly the behavior of slow/fast-mode waves/shocks and of current-driven helical kink instabilities. However, the prospects of these ideas applying to a large number of other jet systems may make this worth the effort.Comment: 7 pages, 4 figures, Accepted for Publication in Ap

Geochronology of Type Santacrucian (Middle Tertiary) Land Mammal Age, Patagonia, Argentina

Mammal-bearing lacustrine and tuffaceous sediments from three localities of the Santa Cruz Formation, type fauna of the Santacrucian Land Mammal Age, in Patagonia, southern Argentina, are calibrated by radioisotope dating with the aid of magnetostratigraphy. The strata range from about 17.6 Ma to perhaps 16.0 Ma, and are thus of late-early Miocene age. The Santacrucian Land Mammal Age ranges from about 18.0 Ma to about 15.0 Ma

Mobile Object Tracking in Panoramic Video and LiDAR for Radiological Source-Object Attribution and Improved Source Detection

The addition of contextual sensors to mobile radiation sensors provides valuable information about radiological source encounters that can assist in adjudication of alarms. This study explores how computer-vision based object detection and tracking analyses can be used to augment radiological data from a mobile detector system. We study how contextual information (streaming video and LiDAR) can be used to associate dynamic pedestrians or vehicles with radiological alarms to enhance both situational awareness and detection sensitivity. Possible source encounters were staged in a mock urban environment where participants included pedestrians and vehicles moving in the vicinity of an intersection. Data was collected with a vehicle equipped with 6 NaI(Tl) 2 inch times 4 inch times 16 inch detectors in a hexagonal arrangement and multiple cameras, LiDARs, and an IMU. Physics-based models that describe the expected count rates from tracked objects are used to correlate vehicle and/or pedestrian trajectories to measured count-rate data through the use of Poisson maximum likelihood estimation and to discern between source-carrying and non-source-carrying objects. In this work, we demonstrate the capabilities of our source-object attribution approach as applied to a mobile detection system in the presence of moving sources to improve both detection sensitivity and situational awareness in a mock urban environment