258 research outputs found

    Development of a Sustainable Water Resource for the Big Creek Watershed

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    Proceedings of the 2001 Georgia Water Resources Conference, April 26 and 27, 2001, Athens, Georgia.The Big Creek Water Quality Management Plan has been a cooperative effort of Cherokee, Forsyth and Fulton Counties, as well as the Cities of Alpharetta, Cumming and Roswell to develop a mutually agreeable water quality protection Plan for the Big Creek Watershed. The Big Creek Watershed straddles the rapidly growing Georgia 400 Corridor in the northern part of Metropolitan Atlanta. It is a water supply for the City of Roswell and has an area of about 99 square miles at the Roswell water intake. The project purposes included: achieving and maintaining a high quality water supply; minimizing flooding, property damage and stream impacts; protecting wetlands and establish greenways; meeting minimum Georgia DNR water supply watershed criteria or developing acceptable alternatives; understanding the impacts of urbanization; and considering options for and developing multi jurisdictional cooperation. The study encompassed watershed characterization, assessment of water quality and quantity issues, assessment of habitat and social issues and the selection of best management practices (BMP's) to meet water quality, water quantity, habitat and social goals. Study tasks included forecasting future land use and impervious areas, assessing current and future impacts and evaluating alternate management and protection scenarios.Sponsored and Organized by: U.S. Geological Survey, Georgia Department of Natural Resources, Natural Resources Conservation Service, The University of Georgia, Georgia State University, Georgia Institute of TechnologyThis book was published by the Institute of Ecology, The University of Georgia, Athens, Georgia 30602-2202. The views and statements advanced in this publication are solely those of the authors and do not represent official views or policies of The University of Georgia, the U.S. Geological Survey, the Georgia Water Research Institute as authorized by the Water Resources Research Act of 1990 (P.L. 101-397) or the other conference sponsors

    Dilepton and Photon Emission Rates from a Hadronic Gas

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    We analyze the dilepton and photon emission rates from a hadronic gas using chiral reduction formulas and a virial expansion. The emission rates are reduced to pertinent vacuum correlation functions, most of which can be assessed from experiment. Our results indicate that in the low mass region, the dilepton and photon rates are enhanced compared to most of the calculations using chiral Lagrangians. The enhancement is further increased through a finite pion chemical potential. An estimate of the emission rates is also made using Haag's expansion for the electromagnetic current. The relevance of these results to dilepton and photon emission rates in heavy-ion collisions is discussed.Comment: 7 pages, LaTeX using revTeX, 6 figures imbedded in text. Figures slightly changed, text left unchange

    Photon Rates for Heavy-Ion Collisions from Hidden Local Symmetry

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    We study photon production from the hidden local symmetry approach that includes pions, rho and a1 mesons and compute the corresponding photon emission rates from a hadronic gas in thermal equilibrium. Together with experimental radiative decay widths of the background, these rates are used in a relativistic transport model to calculate single photon spectra in heavy-ion collisions at SPS energies. We then employ this effective theory to test three scenarios for the chiral phase transition in high-temperature nuclear matter including decreasing vector meson masses. Although all calculations respect the upper bound set by the WA80 Collaboration, we find the scenarios could be distinguished with more detailed data.Comment: 12 pages, 12 Postscript figures; discussion of thermal equilibrium rates expanded, minor corrections to text and graph

    Aerosol meteorology of Maritime Continent for the 2012 7SEAS southwest monsoon intensive study - Part 2: Philippine receptor observations of fine-scale aerosol behavior

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    Abstract. The largest 7 Southeast Asian Studies (7SEAS) operations period within the Maritime Continent (MC) occurred in the August–September 2012 biomass burning season. Data included were observations aboard the M/Y Vasco, dispatched to the Palawan Archipelago and Sulu Sea of the Philippines for September 2012. At these locations, the Vasco observed MC smoke and pollution entering the southwest monsoon (SWM) monsoonal trough. Here we describe the research cruise findings and the finer-scale aerosol meteorology of this convectively active region. This 2012 cruise complemented a 2-week cruise in 2011 and was generally consistent with previous findings in terms of how smoke emission and transport related to monsoonal flows, tropical cyclones (TC), and the covariance between smoke transport events and the atmosphere's thermodynamic structure. Biomass burning plumes were usually mixed with significant amounts of anthropogenic pollution. Also key to aerosol behavior were squall lines and cold pools propagating across the South China Sea (SCS) and scavenging aerosol particles in their path. However, the 2012 cruise showed much higher modulation in aerosol frequency than its 2011 counterpart. Whereas in 2011 large synoptic-scale aerosol events transported high concentrations of smoke into the Philippines over days, in 2012 measured aerosol events exhibited a much shorter-term variation, sometimes only 3–12 h. Strong monsoonal flow reversals were also experienced in 2012. Nucleation events in cleaner and polluted conditions, as well as in urban plumes, were observed. Perhaps most interestingly, several cases of squall lines preceding major aerosol events were observed, as opposed to 2011 observations where these lines largely scavenged aerosol particles from the marine boundary layer. Combined, these observations indicate pockets of high and low particle counts that are not uncommon in the region. These perturbations are difficult to observe by satellite and very difficult to model. Indeed, the Navy Aerosol Analysis and Prediction System (NAAPS) simulations captured longer period aerosol events quite well but largely failed to capture the timing of high-frequency phenomena. Ultimately, the research findings of these cruises demonstrate the real world challenges of satellite-based missions, significant aerosol life cycle questions such as those the future Aerosol/Clouds/Ecosystems (ACE) will investigate, and the importance of small-scale phenomena such as sea breezes, squall lines, and nucleation events embedded within SWM patterns in dominating aerosol life cycle and potential relationships to clouds

    Human neutrophil clearance of bacterial pathogens triggers anti-microbial gamma delta T cell responses in early infection

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    Human blood Vc9/Vd2 T cells, monocytes and neutrophils share a responsiveness toward inflammatory chemokines and are rapidly recruited to sites of infection. Studying their interaction in vitro and relating these findings to in vivo observations in patients may therefore provide crucial insight into inflammatory events. Our present data demonstrate that Vc9/Vd2 T cells provide potent survival signals resulting in neutrophil activation and the release of the neutrophil chemoattractant CXCL8 (IL-8). In turn, Vc9/Vd2 T cells readily respond to neutrophils harboring phagocytosed bacteria, as evidenced by expression of CD69, interferon (IFN)-c and tumor necrosis factor (TNF)-a. This response is dependent on the ability of these bacteria to produce the microbial metabolite (E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate (HMB-PP), requires cell-cell contact of Vc9/Vd2 T cells with accessory monocytes through lymphocyte function-associated antigen-1 (LFA-1), and results in a TNF-a dependent proliferation of Vc9/Vd2 T cells. The antibiotic fosmidomycin, which targets the HMB-PP biosynthesis pathway, not only has a direct antibacterial effect on most HMB-PP producing bacteria but also possesses rapid anti-inflammatory properties by inhibiting cd T cell responses in vitro. Patients with acute peritoneal-dialysis (PD)-associated bacterial peritonitis – characterized by an excessive influx of neutrophils and monocytes into the peritoneal cavity – show a selective activation of local Vc9/Vd2 T cells by HMB-PP producing but not by HMB-PP deficient bacterial pathogens. The cd T celldriven perpetuation of inflammatory responses during acute peritonitis is associated with elevated peritoneal levels of cd T cells and TNF-a and detrimental clinical outcomes in infections caused by HMB-PP positive microorganisms. Taken together, our findings indicate a direct link between invading pathogens, neutrophils, monocytes and microbe-responsive cd T cells in early infection and suggest novel diagnostic and therapeutic approaches.Martin S. Davey, Chan-Yu Lin, Gareth W. Roberts, Sinéad Heuston, Amanda C. Brown, James A. Chess, Mark A. Toleman, Cormac G.M. Gahan, Colin Hill, Tanya Parish, John D. Williams, Simon J. Davies, David W. Johnson, Nicholas Topley, Bernhard Moser and Matthias Eber

    Generation of Human Antigen-Specific Monoclonal IgM Antibodies Using Vaccinated “Human Immune System” Mice

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    Passive transfer of antibodies not only provides immediate short-term protection against disease, but also can be exploited as a therapeutic tool. However, the 'humanization' of murine monoclonal antibodies (mAbs) is a time-consuming and expensive process that has the inherent drawback of potentially altering antigenic specificity and/or affinity. The immortalization of human B cells represents an alternative for obtaining human mAbs, but relies on the availability of biological samples from vaccinated individuals or convalescent patients. In this work we describe a novel approach to generate fully human mAbs by combining a humanized mouse model with a new B cell immortalization technique. After transplantation with CD34+CD38⁻ human hematopoietic progenitor cells, BALB/c Rag2⁻/⁻IL-2Rγc⁻/⁻ mice acquire a human immune system and harbor B cells with a diverse IgM repertoire. "Human Immune System" mice were then immunized with two commercial vaccine antigens, tetanus toxoid and hepatitis B surface antigen. Sorted human CD19+CD27+ B cells were retrovirally transduced with the human B cell lymphoma (BCL)-6 and BCL-XL genes, and subsequently cultured in the presence of CD40-ligand and IL-21. This procedure allows generating stable B cell receptor-positive B cells that secrete immunoglobulins. We recovered stable B cell clones that produced IgM specific for tetanus toxoid and the hepatitis B surface antigen, respectively. This work provides the proof-of-concept for the usefulness of this novel method based on the immunization of humanized mice for the rapid generation of human mAbs against a wide range of antigen

    Measurement of the Atmospheric Muon Charge Ratio at TeV Energies with MINOS

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    The 5.4 kton MINOS far detector has been taking charge-separated cosmic ray muon data since the beginning of August, 2003 at a depth of 2070 meters-water-equivalent in the Soudan Underground Laboratory, Minnesota, USA. The data with both forward and reversed magnetic field running configurations were combined to minimize systematic errors in the determination of the underground muon charge ratio. When averaged, two independent analyses find the charge ratio underground to be 1.374 +/- 0.004 (stat.) +0.012 -0.010(sys.). Using the map of the Soudan rock overburden, the muon momenta as measured underground were projected to the corresponding values at the surface in the energy range 1-7 TeV. Within this range of energies at the surface, the MINOS data are consistent with the charge ratio being energy independent at the two standard deviation level. When the MINOS results are compared with measurements at lower energies, a clear rise in the charge ratio in the energy range 0.3 -- 1.0 TeV is apparent. A qualitative model shows that the rise is consistent with an increasing contribution of kaon decays to the muon charge ratio.Comment: 16 pages, 17 figure

    Measurement of neutrino velocity with the MINOS detectors and NuMI neutrino beam

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    The velocity of a ~3 GeV neutrino beam is measured by comparing detection times at the near and far detectors of the MINOS experiment, separated by 734 km. A total of 473 far detector neutrino events was used to measure (v-c)/c=5.12.910-5 (at 68% C.L.). By correlating the measured energies of 258 charged-current neutrino events to their arrival times at the far detector, a limit is imposed on the neutrino mass of mnu<50 MeV/c2 (99% C.L.)

    Low-dose TNF augments fracture healing in normal and osteoporotic bone by up-regulating the innate immune response

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    The mechanism by which trauma initiates healing remains unclear. Precise understanding of these events may define interventions for accelerating healing that could be translated to the clinical arena. We previously reported that addition of low-dose recombinant human TNF (rhTNF) at the fracture site augmented fracture repair in a murine tibial fracture model. Here, we show that local rhTNF treatment is only effective when administered within 24h of injury, when neutrophils are the major inflammatory cell infiltrate. Systemic administration of anti-TNF impaired fracture healing. Addition of rhTNF enhanced neutrophil recruitment and promoted recruitment of monocytes through CCL2 production. Conversely, depletion of neutrophils or inhibition of the chemokine receptor CCR2 resulted in significantly impaired fracture healing. Fragility, or osteoporotic, fractures represent a major medical problem as they are associated with permanent disability and premature death. Using a murine model of fragility fractures, we found that local rhTNF treatment improved fracture healing during the early phase of repair. If translated clinically, this promotion of fracture healing would reduce the morbidity and mortality associated with delayed patient mobilization

    Computational Modeling of PI3K/AKT and MAPK Signaling Pathways in Melanoma Cancer

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    Background Malignant melanoma is an aggressive tumor of the skin and seems to be resistant to current therapeutic approaches. Melanocytic transformation is thought to occur by sequential accumulation of genetic and molecular alterations able to activate the Ras/Raf/MEK/ERK (MAPK) and/or the PI3K/AKT (AKT) signalling pathways. Specifically, mutations of B-RAF activate MAPK pathway resulting in cell cycle progression and apoptosis prevention. According to these findings, MAPK and AKT pathways may represent promising therapeutic targets for an otherwise devastating disease. Result Here we show a computational model able to simulate the main biochemical and metabolic interactions in the PI3K/AKT and MAPK pathways potentially involved in melanoma development. Overall, this computational approach may accelerate the drug discovery process and encourages the identification of novel pathway activators with consequent development of novel antioncogenic compounds to overcome tumor cell resistance to conventional therapeutic agents. The source code of the various versions of the model are available as S1 Archive
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