4,949 research outputs found
On the bilinear covariants associated to mass dimension one spinors
In this paper we approach the issue of Clifford algebra basis deformation,
allowing for bilinear covariants associated to Elko spinors which satisfy the
Fierz-Pauli-Kofink identities. We present a complete analysis of covariance,
taking into account the involved dual structure associated to Elko. Moreover,
the possible generalizations to the recently presented new dual structure are
performed.Comment: 9 pages, 0 figure
Rapid Aerosol Transmission of Salmonella Among Turkeys in a Simulated Holding-Shed Environment
Once turkeys arrive at Midwest processing plants, they are usually held in large open-sided sheds for 1 to 4 h, waiting to be unloaded. In hot, humid weather, large fans are used to cool the birds. The resultant air currents distribute a significant amount of dust to the turkeys. The dust created in this environment could be a factor in the number of Salmonella-contaminated turkeys entering slaughter plants. The objective of this study was to determine if rapid transmission of Salmonella in turkeys could occur from exposure toSalmonella-contaminated dust similar to what may be experienced in holding sheds or in other high-dust environments prior to slaughter. In the first experiment, trials of 3 different concentrations of Salmonella (1.2 × 109, 2.6 × 107, and 2.6 × 105 cfu/g) were conducted to determine if transmission ofSalmonella enterica serovar Typhimurium var. typhimuriumχ4232 to turkeys 2 to 4 h after aerosol exposure to contaminated feces is possible. Results showed that turkeys became infected after 2 h of exposure to airborne-contaminated feces with a concentration level of 2.6 × 105 cfu of SalmonellaTyphimurium/g. In the second experiment, consisting of 3 trials, 1 bank (5 cages wide and 3 cages high) of turkeys (n = 15 birds per trial) was exposed to another bank of cages of S. Typhimurium-inoculated (n = 15) birds for 2 to 4 h using a fan similar to the type in processing-plant cooling sheds. Results from this experiment demonstrated that birds could be contaminated with S.Typhimurium after 2 h of exposure. Results of both studies implicate contaminated dust as a route of rapid airborne transmission of Salmonella in turkeys. Processes that generate significant dust prior to slaughter should be regarded as critical control points for Salmonella
Nonemptiness and smoothness of twisted Brill–Noether loci
Let V be a vector bundle over a smooth curve C. In this paper, we study twisted Brill–Noether loci parametrising stable bundles E of rank n and degree e with the property that h0(C,V⊗E)≥k. We prove that, under conditions similar to those of Teixidor i Bigas and of Mercat, the Brill–Noether loci are nonempty and in many cases have a component which is generically smooth and of the expected dimension. Along the way, we prove the irreducibility of certain components of both twisted and “nontwisted” Brill–Noether loci. We describe the tangent cones to the twisted Brill–Noether loci. We end with an example of a general bundle over a general curve having positive-dimensional twisted Brill–Noether loci with negative expected dimension
The radical cation of bacteriochlorophyll b. A liquid-phase endor and triple resonance study
The previous termradical cationnext term of bacterioehlorophyll b (BChl b) is investigated by ENDOR and TRIPLE resonance in liquid solution. The experimental hyperfine coupling constants, ten proton and three nitrogen couplings, are compared with the predictions from advanced molecular-orbital calculations (RHF INDO/SP). The detailed picture obtained of the spin density distribution is a prerequisite for the investigation of the primary electron donor previous termradical cationnext term in BChl b containing photosynthetic bacteria
A Blow-Up Criterion for Classical Solutions to the Compressible Navier-Stokes Equations
In this paper, we obtain a blow up criterion for classical solutions to the
3-D compressible Naiver-Stokes equations just in terms of the gradient of the
velocity, similar to the Beal-Kato-Majda criterion for the ideal incompressible
flow. In addition, initial vacuum is allowed in our case.Comment: 25 page
- …