754 research outputs found

    Shigatoxin E. coli (STEC) in Public Park at Different Seasons of the Year

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    BACKGROUND: In the U.S. STEC HUS is the most common cause of acute renal failure in children. In TN from 1996-2017 there were 2008 STEC cases were reported. Every year in the U.S, there 36 reported mortality each year. At our local children’s hospital, 4-5 children are hospitalized with STEC infection each year. Some of these children had no history of ingesting food items that could have placed them at risk to develop STEC infection; however, there are other ways that humans could get infected, such as exposure to contaminated water from cattle farms. GOALS: To determine if there are differences in the presence of STEC at a local park at different seasons of the year. METHODS: Fifty (50) ml of water samples were collected from a creek in 2 areas of public park in Johnson City, TN. Samples were inoculated to Sorbitol McConkey Agar (SMAC) plates under sterile techniques & incubated at 36C for 18 hours under aerobic conditions. RESULTS: Table demonstrating presence of STEC from water samples at different seasons of the year. SEASON OF THE YEAR # COLONIES FOUNDERS PARK # COLONIES LIBRARY PARK SUMMER JUNE 2018 A:1 B:1 C:2 TOTAL: 4 A: 3 B: 2 C: 1 TOTAL: 6 FALL SEPT 2018 A: 1 B: 3 C: 2 TOTAL: 6 A: 1 B:2 C:4 TOTAL: 7 WINTER DEC 2018 A: 1 B: 0 C: 1 TOTAL: 2 A: 0 B: 1 C: 1 TOTAL: 2 SPRING MARCH 2019 A: 2 B: 2 C:1 TOTAL: 5 A: 0 B: 0 C: 0 TOTAL: 0 DISCUSSION/ CONCLUSION: STEC was present at almost every season of the year. Public health measures should be undertaken to inform the community that these waters around public parks are contaminated with STEC to prevent STEC infection. References: TN Dept of Health CEDEP report CDC websit

    Environment-induced dynamical chaos

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    We examine the interplay of nonlinearity of a dynamical system and thermal fluctuation of its environment in the ``physical limit'' of small damping and slow diffusion in a semiclassical context and show that the trajectories of c-number variables exhibit dynamical chaos due to the thermal fluctuations of the bath.Comment: Revtex, 4 pages and 4 figure

    Droplet actuation induced by coalescence: experimental evidences and phenomenological modeling

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    This paper considers the interaction between two droplets placed on a substrate in immediate vicinity. We show here that when the two droplets are of different fluids and especially when one of the droplet is highly volatile, a wealth of fascinating phenomena can be observed. In particular, the interaction may result in the actuation of the droplet system, i.e. its displacement over a finite length. In order to control this displacement, we consider droplets confined on a hydrophilic stripe created by plasma-treating a PDMS substrate. This controlled actuation opens up unexplored opportunities in the field of microfluidics. In order to explain the observed actuation phenomenon, we propose a simple phenomenological model based on Newton's second law and a simple balance between the driving force arising from surface energy gradients and the viscous resistive force. This simple model is able to reproduce qualitatively and quantitatively the observed droplet dynamics

    Semiclassical Instability of the Cauchy Horizon in Self-Similar Collapse

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    Generic spherically symmetric self-similar collapse results in strong naked-singularity formation. In this paper we are concerned with particle creation during a naked-singularity formation in spherically symmetric self-similar collapse without specifying the collapsing matter. In the generic case, the power of particle emission is found to be proportional to the inverse square of the remaining time to the Cauchy horizon (CH). The constant of proportion can be arbitrarily large in the limit to marginally naked singularity. Therefore, the unbounded power is especially striking in the case that an event horizon is very close to the CH because the emitted energy can be arbitrarily large in spite of a cutoff expected from quantum gravity. Above results suggest the instability of the CH in spherically symmetric self-similar spacetime from quantum field theory and seem to support the existence of a semiclassical cosmic censor. The divergence of redshifts and blueshifts of emitted particles is found to cause the divergence of power to positive or negative infinity, depending on the coupling manner of scalar fields to gravity. On the other hand, it is found that there is a special class of self-similar spacetimes in which the semiclassical instability of the CH is not efficient. The analyses in this paper are based on the geometric optics approximation, which is justified in two dimensions but needs justification in four dimensions.Comment: 14 pages, 4 figures, minor errors corrected and some sentences added in the introduction, accepted for publication in Physical Review

    Relativistic quantum clocks

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    The conflict between quantum theory and the theory of relativity is exemplified in their treatment of time. We examine the ways in which their conceptions differ, and describe a semiclassical clock model combining elements of both theories. The results obtained with this clock model in flat spacetime are reviewed, and the problem of generalizing the model to curved spacetime is discussed, before briefly describing an experimental setup which could be used to test of the model. Taking an operationalist view, where time is that which is measured by a clock, we discuss the conclusions that can be drawn from these results, and what clues they contain for a full quantum relativistic theory of time.Comment: 12 pages, 4 figures. Invited contribution for the proceedings for "Workshop on Time in Physics" Zurich 201

    Search for the Rare Decay KL --> pi0 ee

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    The KTeV/E799 experiment at Fermilab has searched for the rare kaon decay KL--> pi0ee. This mode is expected to have a significant CP violating component. The measurement of its branching ratio could support the Standard Model or could indicate the existence of new physics. This letter reports new results from the 1999-2000 data set. One event is observed with an expected background at 0.99 +/- 0.35 events. We set a limit on the branching ratio of 3.5 x 10^(-10) at the 90% confidence level. Combining the results with the dataset taken in 1997 yields the final KTeV result: BR(KL --> pi0 ee) < 2.8 x 10^(-10) at 90% CL.Comment: 4 pages, three figure

    Search for direct CP-violation in K+- --> pi+-pi0pi0 decays

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    A search for direct CP-violation in K+- --> pi+-pi0pi0 decays based on 47.14 million events has been performed by the NA48/2 experiment at the CERN SPS. The asymmetry in the Dalitz plot linear slopes A_g=(g^+ - g^-)/(g^+ + g^-) is measured to be A_g=(1.8 +- 2.6).10^{-4}. The design of the experiment and the method of analysis provide good control of instrumental charge asymmetries in this measurement. The precision of the result is limited by statistics and is almost one order of magnitude better than that of previous measurements by other experiments.Comment: 14 page

    Tidal resource extraction in the Pentland Firth, UK : Potential impacts on flow regime and sediment transport in the Inner Sound of Stroma

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    Large-scale extraction of power from tidal streams within the Pentland Firth is expected to be underway in the near future. The Inner Sound of Stroma in particular has attracted significant commercial interest. To understand potential environmental impacts of the installation of a tidal turbine array a case study based upon the Inner Sound is considered. A numerical computational fluid dynamics model, Fluidity, is used to conduct a series of depth-averaged simulations to investigate velocity and bed shear stress changes due to the presence of idealised tidal turbine arrays. The number of turbines is increased from zero to 400. It is found that arrays in excess of 85 turbines have the potential to affect bed shear stress distributions in such a way that the most favourable sites for sediment accumulation migrate from the edges of the Inner Sound towards its centre. Deposits of fine gravel and coarse sand are indicated to occur within arrays of greater than 240 turbines with removal of existing deposits in the shallower channel margins also possible. The effects of the turbine array may be seen several kilometres from the site which has implications not only on sediment accumulation, but also on the benthic fauna
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