1,160 research outputs found
Salmonella and campylobacter in organic egg production - with special reference to the Finnish situation
In Finland, an ongoing (2003-2005) research project on organic egg production, animal welfare and food safety is examining campylobacter and salmonella contamination of approximately 20 organic layer farms. Adequate biosecurity levels, lowering the number of potential zoonotic infection sources in the vicinity of hen houses and vaccination of hens against S. Enteritidis are available tools to decrease contamination of organic laying hens by campylobacters or salmonella
The Generation of Turbulence by Oscillating Structures in Superfluid Helium at Very Low Temperatures
The paper is concerned with the interpretation of many experiments that have
been reported recently on the production of quantum turbulence by oscillating
spheres, wires and grids in both 4He and 3He-B at temperatures so low that
there is a negligible fraction of normal fluid. The experimental results are
compared with those obtained in analogous experiments with classical fluids and
with preliminary simulations of the quantum turbulence. Particular attention is
paid to observed values of drag coefficients and to the very different critical
velocities observed in 4He and 3He. It is tentatively concluded that in the
case of 4He behaviour may well be similar to that observed in the classical
analogues, with relatively small changes when the characteristic size of the
oscillating structure is not large compared with the quantized vortex spacing,
but that in the case of 3He behaviour is very different and due perhaps to very
rapid intrinsic nucleation of the quantized vortices.Comment: 13 pages, 9 figure
Dynamic Remanent Vortices in Superfluid 3He-B
We investigate the decay of vortices in a rotating cylindrical sample of
3He-B, after rotation has been stopped. With decreasing temperature vortex
annihilation slows down as the damping in vortex motion, the mutual friction
dissipation \alpha(T), decreases almost exponentially. Remanent vortices then
survive for increasingly long periods, while they move towards annihilation in
zero applied flow. After a waiting period \Delta t at zero flow, rotation is
reapplied and the remnants evolve to rectilinear vortices. By counting these
lines, we measure at temperatures above the transition to turbulence ~0.6T_c
the number of remnants as a function of \alpha(T) and \Delta t. At temperatures
below the transition to turbulence T \lesssim 0.55 T_c, remnants expanding in
applied flow become unstable and generate in a turbulent burst the equilibrium
number of vortices. Here we measure the onset temperature T_on of turbulence as
a function of \Delta t, applied flow velocity, and length of sample L.Comment: Submitted to the proceedings of the Quantum Fluids and Solids
Conference 2006 (to be published in Journal of Low Temperature Physics 2007)
New data are adde
Initial treatment strategy and clinical outcomes in Finnish MS patients : a propensity-matched study
Background The optimal treatment strategy with disease-modifying therapies (DMTs) in relapsing-remitting multiple sclerosis (RRMS) remains uncertain. Objective To compare outcomes of initial treatment with infusion therapies and starting therapy with medium efficacy therapy in a propensity-matched cohort of Finnish RRMS patients. Methods A total of 154 RRMS patients initiating natalizumab, alemtuzumab, ocrelizumab or rituximab as first DMT (high efficacy DMT, heDMT group) and 1771 patients initially treated with injectable therapies, teriflunomide or dimethylfumarate and escalated based on disease activity (moderate efficacy DMT, meDMT group) were identified from the Finnish MS registry. Nearest neighbor propensity matching (1:1, caliper 0.1) was performed for age, sex, baseline Expanded Disability Status Scale (EDSS), annual relapse rate (ARR) one year prior DMT and time since MS symptom onset. Primary outcome was time to 6-month confirmed EDSS progression and the secondary outcome time to first relapse. Results In the propensity-matched group comparisons, the probability of 6-month confirmed disability progression (CDP) at 5 years after DMT start was 28.4% (95% CI 15.7-39.3) in the heDMT group (n = 66) and 47.0% (95% CI 33.1-58.1) in meDMT group (n = 66), p = 0.013. Probability of relapse at 5 years was 34.6% (95% CI 24.1-43.6) for heDMT (n = 105) and 47.2% (95% CI 36.6-56.1) for meDMT (n = 105), p = 0.019. Conclusions Initiating MS-therapy with heDMT significantly reduced the risk of 5-year disability progression and relapse compared to using meDMT as first DMT choice in propensity-matched groups of Finnish MS-patients.Peer reviewe
Organic egg production in Finland - animal health, welfare and food safety issues
A total of 20 out of 23 commercial organic layer farms took part in the research. Data were collected through observation and by interviewing the producer, using a semi-structured interview guide. Laying hen welfare was estimated using environment-based and animal-based methods. Fresh faecal samples were collected from the floor for analysis of campylobacter and salmonella bacteria and for internal parasite identification
Organic egg production in Finland: management of animal welfare and food safety
A total of 20 out of 23 commercial organic layer farms (in excess of 80 % of all commercial Finnish organic farms year 2003) took part in the ongoing research, which identifies risk factors and potential solutions for laying hen welfare and food safety. Data was collected during two farm visits by interviewing the producer, using a semi-structured interview guide, making environment and animal-based observations and collecting samples
Turbulent Vortex Flow Responses at the AB Interface in Rotating Superfluid 3He-B
In a rotating two-phase sample of 3He-B and magnetic-field stabilized 3He-A
the large difference in mutual friction dissipation at 0.20 Tc gives rise to
unusual vortex flow responses. We use noninvasive NMR techniques to monitor
spin down and spin up of the B-phase superfluid component to a sudden change in
the rotation velocity. Compared to measurements at low field with no A-phase,
where these responses are laminar in cylindrically symmetric flow, spin down
with vortices extending across the AB interface is found to be faster,
indicating enhanced dissipation from turbulence. Spin up in turn is slower,
owing to rapid annihilation of remanent vortices before the rotation increase.
As confirmed by both our NMR signal analysis and vortex filament calculations,
these observations are explained by the additional force acting on the B-phase
vortex ends at the AB interface.Comment: 6 pages, 6 figure
Measures of weight distribution of dairy cows to detect lameness and the presence of hoof lesions
There is increasing interest in automated methods of detecting lame cows. Hoof lesion data and measures of weight distribution from 61 lactating cows were examined in this study. Lame cows were identified with different numerical rating scores (NRS) used as thresholds (NRS \u3e3 and NRS ≥3.5) for lameness. The ratio of weight applied to a pair of legs (LWR) when the cow was standing was calculated using a special weigh scale, and the cows were gait scored using a 1 to 5 NRS. Hoof lesions were scored and the cows placed into 1 of 4 mutually exclusive categories of hoof lesion: a) no lesions, b) moderate or severe hemorrhages, c) digital dermatitis, and d) sole ulcers. Regression analysis and receiver operating characteristic (ROC) curves were used to analyze the relation between hoof lesions and LWR. A clear relationship was found between NRS and LWR for the cows with sole ulcers (R2 = 0.79). The LWR could differentiate cows with sole ulcers from sound cows with no hoof lesions [area under the curve (AUC) = 0.87] and lame cows from nonlame cows with lameness thresholds NRS \u3e3 (AUC = 0.71) and NRS ≥3.5 (AUC = 0.88). There was no relationship between LWR and NRS for cows with digital dermatitis. Measurement of how cows distribute their weight when standing holds promise as a method of automated detection of lameness
Measures of weight distribution of dairy cows to detect lameness and the presence of hoof lesions
There is increasing interest in automated methods of detecting lame cows. Hoof lesion data and measures of weight distribution from 61 lactating cows were examined in this study. Lame cows were identified with different numerical rating scores (NRS) used as thresholds (NRS \u3e3 and NRS ≥3.5) for lameness. The ratio of weight applied to a pair of legs (LWR) when the cow was standing was calculated using a special weigh scale, and the cows were gait scored using a 1 to 5 NRS. Hoof lesions were scored and the cows placed into 1 of 4 mutually exclusive categories of hoof lesion: a) no lesions, b) moderate or severe hemorrhages, c) digital dermatitis, and d) sole ulcers. Regression analysis and receiver operating characteristic (ROC) curves were used to analyze the relation between hoof lesions and LWR. A clear relationship was found between NRS and LWR for the cows with sole ulcers (R2 = 0.79). The LWR could differentiate cows with sole ulcers from sound cows with no hoof lesions [area under the curve (AUC) = 0.87] and lame cows from nonlame cows with lameness thresholds NRS \u3e3 (AUC = 0.71) and NRS ≥3.5 (AUC = 0.88). There was no relationship between LWR and NRS for cows with digital dermatitis. Measurement of how cows distribute their weight when standing holds promise as a method of automated detection of lameness
Vortex Multiplication in Applied Flow: the Precursor to Superfluid Turbulence
The dynamics of quantized vortices in rotating He-B is investigated in
the low density (single-vortex) regime as a function of temperature. An abrupt
transition is observed at . Above this temperature the number of
vortex lines remains constant, as they evolve to their equilibrium positions.
Below this temperature the number of vortices increases linearly in time until
the vortex density has grown sufficiently for turbulence to switch on. On the
basis of numerical calculations we suggest a mechanism responsible for vortex
formation at low temperatures and identify the mutual friction parameter which
governs its abrupt temperature dependence.Comment: 5 pages, 4 figures; version submitted to Phys. Rev. Let
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