103 research outputs found
Incidence of digital papillomatosis ("hairy warts") in a dairy herd. Response to surgery and autogenous vaccination
Digital papillomatosis (hairy warts) was
diagnosed in a dairy herd with a high level
of lameness (20%). Warts ranged from
mild to moderate to severe, with severity
increasing with length of lactations. All
milking cows (100%) had at least mild
lesions. Cows with severe lesions were
more likely to be lame. Severity of lesions
had no influence on 305-day ME milk production,
days open, or somatic cell counts.
Cows in milk more than 150 days and lame
produced 3 kg less milk per day than cows
that were not lame. Almost all warts were
in the interdigital cleft near the heel of the
rear feet. A few cows had lesions in the
front of the interdigital cleft or on the front
feet. No viral particles were observed or
isolated. A new, Gram-negative, motile,
facultatively anaerobic, spiral-shaped bacteria
was isolated from one lesion. The
cellular fatty acid profile of this bacterium
had no match to any other known bacteria
in any of three computer databases examined.
Cows with severe lesions were assigned
randomly to one of four groups: Group 1:
surgical removal and autogenous vaccination;
Group 2: surgical removal only;
Group 3: autogenous vaccination only, and
Group 4: control. Neither surgical removal
nor autogenous vaccination had a significant
effect on wart severity, lameness, or
milk production when cows were
inspected 10 wk later. Contemporary
evaluation of 249 herdmates revealed a
substantial number of severely affected
cows naturally improved. Of 25 severely
affected herd contemporaries, only 8 were
severely affected 10 wk later. Evidently,
natural improvement of lesions is a common
phenomenon with “hairy warts.
Transverse and longitudinal characterization of electron beams using interaction with optical near-fields
We demonstrate an experimental technique for both transverse and longitudinal
characterization of bunched femtosecond free electron beams. The operation
principle is based on monitoring of the current of electrons that obtained an
energy gain during the interaction with the synchronized optical near-field
wave excited by femtosecond laser pulses. The synchronous
accelerating/decelerating fields confined to the surface of a silicon
nanostructure are characterized using a highly focused sub-relativistic
electron beam. Here the transverse spatial resolution of 450 nm and femtosecond
temporal resolution achievable by this technique are demonstrated
Energy efficiency studies for dual-grating dielectric laser-driven accelerators
Dielectric laser-driven accelerators (DLAs) can provide high accelerating
gradients in the GV/m range due to their having higher breakdown thresholds
than metals, which opens the way for the miniaturization of the next generation
of particle accelerator facilities. Two kinds of scheme, the addition of a
Bragg reflector and the use of pulse-front-tilted (PFT) laser illumination,
have been studied separately to improve the energy efficiency for dual-grating
DLAs. The Bragg reflector enhances the accelerating gradient of the structure,
while the PFT increases the effective interaction length. In this paper, we
investigate numerically the advantages of using the two schemes in conjunction.
Our calculations show that, for a 100-period structure with a period of 2
micrometer, such a design effectively increases the energy gain by more than
100 % when compared to employing the Bragg reflector with a normal laser, and
by about 50 % when using standard structures with a PFT laser. A total energy
gain of as much as 2.6 MeV can be obtained for a PFT laser beam when
illuminating a 2000-period dual-grating structure with a Bragg reflector.Comment: 7 pages, 4 Figures, Proceedings of EAAC2017 Conferenc
The use of cumulative gas and volatile fatty acid production to predict in vitro fermentation kinetics of Italian ryegrass leaf cell walls and contents at various time intervals
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