Spatial and temporal patterns of pig herds diagnosed with Postweaning Multisystemic Wasting Syndrome (PMWS) during the first two years of its occurrence in Denmark     

Vigre H  Baekbo P  Jorsal SE  Bille-Hansen V  Hassing AG  Enøe C  Bøtner A 《Veterinary microbiology》2005,110(1-2):17-26

The clinical syndrome Postweaning Multisystemic Wasting Syndrome (PMWS) in pigs has emerged globally during the last decade. In October 2001, the first pig herd diagnosed with PMWS was reported in Denmark, and since then the number of herds diagnosed with PMWS has increased markedly. The etiology of PMWS is not well understood, but increased knowledge of the causal factors is prerequisite for applying preventive interventions. In this study we described the temporal (time of diagnosis), spatial (location of herds) and spatio-temporal pattern of Danish pig herds diagnosed with PMWS during the first two years after the first herd was diagnosed, and we tested for spatial and spatio-temporal clustering using scan statistics. The study population consisted of pig herds that during the study period (October 2001-September 2003) performed diagnostic submissions to the two major veterinary diagnostic laboratories in Denmark (6724 herds). Of these, 277 herds were diagnosed with PMWS. Two statistically significant spatial clusters of herds diagnosed with PMWS were identified. These clusters included 11% and 8% of the study herds, respectively. Within these two clusters the relative risk for a herd to be diagnosed with PMWS was twice as high as expected. One statistically significant spatio-temporal cluster was identified between February and May 2002. We discuss different hypotheses that could explain why pig herds diagnosed with PMWS were clustered both spatially and spatio-temporally, and conclude that the results support the hypothesis that PMWS is caused by introduction of a new, unidentified, pathogen into the Danish pig production.  相似文献   

Structural biology. The inner workings of a dynamic duo     

Poulsen H  Nissen P 《Science (New York, N.Y.)》2012,335(6067):416-417

  相似文献   

The effect of boron upon leaf development and growth of the apple cultivar ‘Cox’s Orange Pippin’     

Poul Hansen 《The Journal of Horticultural Science and Biotechnology》2013,88(3):211-216

One-year-old ‘Cox’s Orange Pippin’ trees planted in pots in sand culture in the spring of 1970 were (during the growing seasons of 1970–72) watered with nutrient solutions containing 0, 0.12, 0.23, 1.2, 3.5 or 7.0 mg boron per litre.

With increasing boron supply, the boron concentration of the leaves increased, the growth of current year’s shoots and to some extent of other plant parts increased, and summer leaf-fall and the occurrence of necrotic leaf spots (‘Cox spots’) decreased. The percentage of healthy leaves was greatest when boron in leaf dry matter was about 30 ppm.

In 1972 the trees with highest boron supply suffered from incipient boron toxicity and increased incidence of ‘Cox disease’ flowering was delayed, and the percentage of dead buds was increased. In the latter part of the summer the leaves curled upwards, turned purple and became brittle.  相似文献   

Airborne spread of foot-and-mouth disease – Model intercomparison     

John Gloster  Andrew Jones  Alison Redington  Laura Burgin  Jens H. Sørensen  Richard Turner  Michael Dillon  Pam Hullinger  Matthew Simpson  Poul Astrup  Graeme Garner  Paul Stewart  Réal D’Amours  Robert Sellers  David Paton 《Veterinary journal (London, England : 1997)》2010,183(3):278-286

Foot-and-mouth disease virus (FMDV) spreads by direct contact between animals, by animal products (milk, meat and semen), by mechanical transfer on people or fomites and by the airborne route, with the relative importance of each mechanism depending on the particular outbreak characteristics. Atmospheric dispersion models have been developed to assess airborne spread of FMDV in a number of countries, including the UK, Denmark, Australia, New Zealand, USA and Canada. These models were compared at a Workshop hosted by the Institute for Animal Health/Met Office in 2008. Each modeller was provided with data relating to the 1967 outbreak of FMD in Hampshire, UK, and asked to predict the spread of FMDV by the airborne route.A number of key issues emerged from the Workshop and subsequent modelling work: (1) in general all models predicted similar directions for livestock at risk, with much of the remaining differences strongly related to differences in the meteorological data used; (2) determination of an accurate sequence of events on the infected premises is highly important, especially if the meteorological conditions vary substantially during the virus emission period; (3) differences in assumptions made about virus release, environmental fate and susceptibility to airborne infection can substantially modify the size and location of the downwind risk area. All of the atmospheric dispersion models compared at the Workshop can be used to assess windborne spread of FMDV and provide scientific advice to those responsible for making control and eradication decisions in the event of an outbreak of disease.  相似文献   

Application and evaluation of RT-PCR-ELISA for the nucleoprotein and RT-PCR for detection of low-pathogenic H5 and H7 subtypes of avian influenza virus.   总被引：7，自引：0，他引：7  

Karen Dybkaer  Mette Munch  Kurt J Handberg  Poul H J?rgensen 《Journal of veterinary diagnostic investigation》2004,16(1):51-56

  相似文献   

Chitin biosynthesis inhibition and fungicidal effect of thiosemicarbazones of 2-formyl- and 2-acetylpyridine,their hydrogenated derivatives and copper complexes thereof     

Anita Wengel  Niels Jacobsen  Hans Kolind-Andersen  Poul Bjerregaard 《Pest management science》1990,30(2):223-233

Several thiosemicarbazones of 2-formyl- and 2-acetylpyridine dialkylated on N⁴ and non-alkylated on N² were found to be broad-spectrum protectant fungicides with activity particularly against oomycetes. The effect of some of the compounds on chitin biosynthesis was studied, but the low inhibitory activity observed combined with the fungicidal activity spectrum—particularly the high activity against oomycetes—excludes this as their main mode of action. Attempts at enhancing the systemic properties of the compounds by chemical modifications failed.  相似文献   

Determination phase at transition of gonocytes to spermatogonial stem cells improves establishment efficiency of spermatogonial stem cells in domestic cats     

Narong TIPTANAVATTANA  Araya RADTANAKATIKANON  Poul HYTTEL  Hanne HOLM  Supranee BURANAPRADITKUN  Piyathip SETTHAWONG  Mongkol TECHAKUMPHU  Theerawat THARASANIT 《The Journal of reproduction and development》2015,61(6):581-588

The development of germ cells has not been entirely documented in the cat especially the transition phase of the gonocyte to the spermatogonial stem cell (G/SSC). The aims of study were to examine testicular development and to identify the G/SSC transition in order to isolate and culture SSCs in vitro. Testes were divided into 3 groups according to donor age (I, < 4 months; II, 4–6 months; and III, > 6 months). In Exp. 1, we studied testicular development by histology, transmission electron microscopy and immunohistochemistry. In Exp. 2, we determined the expression of GFRα-1, DDX-4 and c-kit and performed flow cytometry. The SSCs isolated from groups II and III were characterized by RT-PCR and TEM (Exp. 3). Chronological changes in the G/SSC transition were demonstrated. The size, morphology and ultrastructure of SSCs were distinguishable from those of gonocytes. The results demonstrated that group II contained the highest numbers of SSCs per seminiferous cord/tubule (17.66 ± 2.20%) and GFRα-1⁺ cells (14.89 ± 5.66%) compared with the other groups. The findings coincided with an increased efficiency of SSC derivation in group II compared with group III (74.33 ± 2.64% vs. 23.33 ± 2.23%). The colonies expressed mRNA for GFRA1, ZBTB16, RET and POU5F1. Our study found that the G/SSC transition occurs at 4–6 months of age. This period is useful for isolation and improves the establishment efficiency of cat SSCs in vitro.  相似文献   

Atom-resolved imaging of dynamic shape changes in supported copper nanocrystals     

Hansen PL  Wagner JB  Helveg S  Rostrup-Nielsen JR  Clausen BS  Topsøe H 《Science (New York, N.Y.)》2002,295(5562):2053-2055

  相似文献   

Seasonal and diurnal variation in the deposition velocity of ozone over a spruce forest in Denmark     

K. Pilegaard  N. O. Jensen  P. Hummelshøj 《Water, air, and soil pollution》1995,85(4):2223-2228

The flux of O₃ was measured by the eddy-correlation method over Norway spruce in periods when the trees had a very low activity, periods with optimum growth, and periods with water stress. The aerodynamic resistance (r _a ), viscous sub-layer resistance (r _b ) and surface resistance (r _c ) to O₃ were calculated from meteorological parameters and the deposition velocity. The canopy stomatal resistance to O₃ was calculated from measurements of the water vapour flux. The deposition velocities showed a diurnal pattern with night-time values of 3.5 mm s^–1 and day-time values of 7 mm s^–1, when the trees had optimal growth conditions. The surface resistance was highly dominating in day-time and the influence of meteorology low. In night-time the surface resistance to 03 was lower than the canopy stomatal resistance. A low surface resistance was also found in winter-time, when the activity of the trees was low. The surface resistance increased when the trees were subject to water stress. It is concluded that stomatal uptake is an important parameter for the deposition of O₃. However, other processes such as destruction of O₃ at surfaces, reaction with NO emitted from the soil, and reactions with radicals produced from VOC's emitted from the forest, should also be taken into consideration.  相似文献   

Phosphoryl transfer and calcium ion occlusion in the calcium pump     

Sørensen TL  Møller JV  Nissen P 《Science (New York, N.Y.)》2004,304(5677):1672-1675

A tight coupling between adenosine triphosphate (ATP) hydrolysis and vectorial ion transport has to be maintained by ATP-consuming ion pumps. We report two crystal structures of Ca2+-bound sarco(endo)plasmic reticulum Ca2+-adenosine triphosphatase (SERCA) at 2.6 and 2.9 angstrom resolution in complex with (i) a nonhydrolyzable ATP analog [adenosine (beta-gamma methylene)-triphosphate] and (ii) adenosine diphosphate plus aluminum fluoride. SERCA reacts with ATP by an associative mechanism mediated by two Mg2+ ions to form an aspartyl-phosphorylated intermediate state (Ca2-E1 approximately P). The conformational changes that accompany the reaction with ATP pull the transmembrane helices 1 and 2 and close a cytosolic entrance for Ca2+, thereby preventing backflow before Ca2+ is released on the other side of the membrane.  相似文献