197 research outputs found
Documentation of animal health in organic pig herds
The health of weaned pigs should be described using several information sources to get an overall assessment of the health state in the herd. In this case study four organic pig herds each fattening between 800 and 3500 pigs per year provided data from clinical examination of a sample of animals, pathological findings at slaughter, post weaning mortality and medicine usage in the herd. Clinical symptoms were present in 8 – 18 % of the pigs, and 2 – 6 % of the pigs showed more serious symptoms of disease. At slaughter 10 – 17 % of the pigs got remarks for pathological lesions, primarily liver spots, abscesses and chronic pericarditis. The post weaning mortality varied between herds, while the usage of medicine was rather low in the herds. The herd health status can be aggregated in many ways. A suggestion is made for the four herds. According to this the good health state is achieved in herds combining a modest medicine usage with a low level of disease, measured by low prevalence of clinical symptoms, low number of remarks at slaughter and low mortality
The whole rock Sm-Nd \u27age\u27 for the 2825 Ma Ikkattoq gneisses (Greenland) is 800 Ma too young: Insights into Archaean TTG petrogenesis
The Ikkattoq gneisses of the Archaean gneiss complex in the Nuuk region, southern West Greenland, are the orthogneiss component within the amphibolite facies Tre Brodre terrane. They have mostly granodioritic compositions, with a small amount of quartz diorite. Sm-Nd isotopic data for a quartz diorite and five granodiorite Ikkattoq gneiss samples from within 5 km of the Ikkattoq (fjord) type locality yielded a regression with a slope equivalent to 2005 +/- 52 Ma (MSWD = 0.72). Regardless of the low MSWD, this cannot be the true age of the Ikkattoq gneisses, because all Ikkattoq gneisses yield U-Pb zircon dates of c. 2825 Ma and they are cut by the undeformed 2560 Ma Qorqut granite complex. This anomalously young regression \u27age\u27 resulted instead from mixing of different Nd components, indicating that the Ikkattoq gneisses are derived from mixed source materials. Taking the true age of the Ikkattoq gneisses as 2825 Ma from U-Pb zircon dating, the range of initial epsilon(Nd) in the Ikkattoq gneisses is -7.1 to -1.8. The negative initial epsilon(Nd) values mean that older, light rare earth enriched, sialic crust contributed to the igneous precursors of the Ikkattoq gneisses. This Nd evidence for contribution of older sialic crust is supported by positive epsilon(Sr) values for the Ikkattoq gneisses. With epsilon(Nd) values as low as -7.1 this older crustal component has to be Eoarchaean. The presence of scarce quartz diorites (low SiO(2), high MgO) suggests that ultramafic rocks (upper mantle?), metasomatised by the passage of fluids or silicic melts, were another contributing source. The Ikkattoq gneisses are proposed as a complex suite incorporating material derived from melting of much older sialic crust and probably upper mantle. The intercalation of tectonostratigraphic terranes during collisional orogeny at c. 2720 Ma destroyed the architecture of this 2825 Ma magmatic system, and the Ikkattoq gneisses now form a slice tectonically isolated from their source region. In terms of trace element parameters, the Ikkattoq gneisses resemble Phanerozoic volcanic arc granites. Thus an Andean-style arc setting for the generation of the Ikkattoq gneiss precursors is possible. Other Archaean TTG suites of the Nuuk region are generally thought to represent predominantly juvenile additions to the crust. In the broadest sense they do, because isotopic work over the past 30 years has demonstrated that they do not represent wholesale recycling of considerably older crust. However in detail, within these broadly juvenile suites, a contribution from older crust can be detected. Thus, c. 3000 Ma type-Nuk gneisses from around Nuuk town show a spread in epsilon(Nd) values down to -1.7. In this case, the likely older crustal component was 3230 Ma quartz diorite that occurs as enclaves in the c. 3000 Ma suite. Thus to a lesser or greater degree, some Meso- to Neoarchaean TTG suites in the Nuuk region display the same internal complexities and evidence for mixed sources as modem arc suites developed near the margins of older crust. (C) 2008 Elsevier BM. All rights reserved
Origin and evolution of formation waters, Alberta Basin, Western Canada sedimentary Basin. I. Chemistry
Inorganic chemical analyses and short-chain aliphatic acid content are used to interpret the origin and compositional evolution of formation waters in the Alberta portion of the Western Canada Sedimentary Basin. Forty-three formation water samples were obtained covering a stratigraphic interval from Devonian to Cretaceous. The data show that: (1) there is a subaerially evaporated brine component that shows no apparent contribution of waters derived from evaporite dissolution; and (2) formation waters have maintained characteristics indicative of subaerially evaporated waters, despite subsequent flushing by gravity-driven meteoric waters in the basin.Formation waters are predominantly Na---Cl brines that contain 4-235g/l total dissolved solids (TDS). Short-chain aliphatic acids (SCA) range up to 932 mg/l, with the following abundance: acetate >> propionate > butyrate. Their number varies randomly with subsurface temperature, depth, geological age and salinity. Instead, SCA distributions appear related to proximity to Jurassic and Mississippian source rocks and to zones of active bacterial SO4 reduction.Based on chemical composition, the formation waters can be divided into three groups. Group I waters are from dominantly carbonate reservoirs and Group II from clastics. Groups I and II are differentiated from Group III in that they are composed of a brine end member, formed by evaporation of sea water beyond the point of halite saturation, that has been subsequently diluted 50-80% by a meteoric water end member. Group III waters are from clastic reservoirs and are dilute, meteoric waters that are decoupled from the more saline, stratigraphically lower, waters of Groups I and II.Group I waters have been influenced by clay mineral transformations in shales surrounding the carbonate reservoirs, ankeritization reactions of reservoir dolomites and calcites, and possible decarboxylation reactions. Group II waters indicate significant leaching reactions, particularly of feldspar and clay minerals. Group I and Group II waters both indicate ion exchange reactions were also possible. The waters are near equilibrium with respect to quartz, calcite, dolomite and barite, but are undersaturated with respect to evaporite minerals (halite, anhydrite). Occurrence of feldspar (predominantly albite) and kaolinite seems to control the population of the water cations. Post-Laramide invasion of meteoric waters provided an impetus for many of the diagenetic reactions in both carbonate, but especially in clastic reservoirs. Subsequent hydrochemical isolation of Group I and II waters from further meteoric influences occurred, resulting in pronounced mixing relations and cross-formational fluid flow replacing the once dominant lateral flow.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28507/1/0000304.pd
Origin and evolution of formation waters, Alberta Basin, Western Canada Sedimentary Basin. II. Isotope systematics and water mixing
Isotopic measurements (Sr, O, D) on formation waters from the Alberta Basin have been made, covering a stratigraphic range from Devonian to Upper Cretaceous. These measurements, combined with chemical compositional trends, give evidence for two distinct water regimes. One hydrological regime is composed of waters hosted in Devonian-Lower Cretaceous reservoirs, the other waters from Upper Cretaceous and younger sedimentary rocks. The two regimes are separated by a regional transgressive shale in the Colorado Group, the Second White Speckled Shale Formation.The waters within the Devonian-Lower Cretaceous regime exhibit a large range in 87Sr/86Sr values (0.7076-0.7129), but have similar Sr concentrations, regardless of host lithology. Bulk rock and late-stage diagenetic cements are less radiogenic than present brines. Importantly, brines from Devonian carbonates possess the most radiogenic Sr isotopic signatures of the waters examined. Devonian shales and/or Cambrian shales may be sources of high 87Sr/86Sr ratios in the carbonate-hosted waters. Waters from the Upper Cretaceous clastic units, which have ratios as low as 0.7058, and diagenetic cements from Upper Cretaceous clastic units appear to have precipitated from fluids similar in Sr isotopic value to modern brines. High Sr concentrations in the Cretaceous clastic waters and sedimentary rocks and correspondingly low 87Sr/86Sr ratios suggest that volcanism in Montana during the Cretaceous may have provided a source of sediments to the study area.Cross-formational upward water migration, superimposed on lateral fluid flow, is required to explain the geochemistry and isotopic systematics in the brines from Devonian-Lower Cretaceous reservoirs. Strontium isotope ratios and Sr contents suggest a two component mixing relation for these waters. This system of waters also exhibits [delta]D values characteristic of meteoric values in the Neogene, reflecting post-Laramide flushing of Tertiary waters throughout the basin, with subsequent hydrochemical isolation from more modern waters. In contrast, waters in Upper Cretaceous reservoirs have O and D isotopic compositions similar to those of present day rainfall; these, in conjunction with very dilute Sr concentrations and low Sr ratios, suggest hydrological isolation from the stratigraphically lower system.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28509/1/0000306.pd
An algebraic approach to the scattering equations
We employ the so-called companion matrix method from computational algebraic geometry, tailored for zero-dimensional ideals, to study the scattering equations. The method renders the CHY-integrand of scattering amplitudes computable using simple linear algebra and is amenable to an algorithmic approach. Certain identities in the amplitudes as well as rationality of the final integrand become immediate in this formalism
Veterinary decision making in relation to metritis - a qualitative approach to understand the background for variation and bias in veterinary medical records
<p>Abstract</p> <p>Background</p> <p>Results of analyses based on veterinary records of animal disease may be prone to variation and bias, because data collection for these registers relies on different observers in different settings as well as different treatment criteria. Understanding the human influence on data collection and the decisions related to this process may help veterinary and agricultural scientists motivate observers (veterinarians and farmers) to work more systematically, which may improve data quality. This study investigates qualitative relations between two types of records: 1) 'diagnostic data' as recordings of metritis scores and 2) 'intervention data' as recordings of medical treatment for metritis and the potential influence on quality of the data.</p> <p>Methods</p> <p>The study is based on observations in veterinary dairy practice combined with semi-structured research interviews of veterinarians working within a herd health concept where metritis diagnosis was described in detail. The observations and interviews were analysed by qualitative research methods to describe differences in the veterinarians' perceptions of metritis diagnosis (scores) and their own decisions related to diagnosis, treatment, and recording.</p> <p>Results</p> <p>The analysis demonstrates how data quality can be affected during the diagnostic procedures, as interaction occurs between diagnostics and decisions about medical treatments. Important findings were when scores lacked consistency within and between observers (variation) and when scores were adjusted to the treatment decision already made by the veterinarian (bias). The study further demonstrates that veterinarians made their decisions at 3 different levels of focus (cow, farm, population). Data quality was influenced by the veterinarians' perceptions of collection procedures, decision making and their different motivations to collect data systematically.</p> <p>Conclusion</p> <p>Both variation and bias were introduced into the data because of veterinarians' different perceptions of and motivations for decision making. Acknowledgement of these findings by researchers, educational institutions and veterinarians in practice may stimulate an effort to improve the quality of field data, as well as raise awareness about the importance of including knowledge about human perceptions when interpreting studies based on field data. Both recognitions may increase the usefulness of both within-herd and between-herd epidemiological analyses.</p
Lymphocytes and macrophages of the epidermis and dermis in lesional psoriatic skin, but not epidermal Langerhans cells, are depleted by treatment with cyclosporin A
Since cyclosporin A (CsA) is an immuno-suppressive agent, its beneficial effect in psoriasis suggests that immune cells may play a role in the pathogenesis and resolution of psoriasis. To determine early effects of CsA in psoriasis, we quantitated immune cells using double immunofluorescence microscopy on biopsy specimens obtained prior to therapy and after 3,7, and 14 days of CsA therapy. CsA therapy resulted in significant reductions in the absolute number of immune cells (including T cells, monocytes/macrophages, and antigen presenting cells) contained within psoriatic skin. The effect was rapid, with over one-half of the reduction in the density of HLe1 + (human leukocyte antigen-1 positive or bone marrow derived) cells, including T cells, activated T cells, monocytes, and Langerhans cells (LCs), occurring within 3 days. Despite the overall reduction in the numbers of immunocytes in the skin, the proportion of T cells, Langerhans cells, and monocytes in relation to the total number of immune cells was unchanged with therapy, reflecting equally proportional losses of each subtype. Dermal CD1 + DR + cells (putative Langerhans cells), which are not found in normal skin but are present in lesional psoriasis skin, were virtually cleared from the papillary dermis after CsA therapy. Although absolute numbers of epidermal Langerhans cells, defined as cells expressing both CD1 (T6) and DR molecules (CD1 + DR + ), were also reduced after CsA, epidermal non-Langerhans CD1 - DR + cells (macrophages, activated T cells, DR - keratinocytes) demonstrated a proportionally greater decrease, with the ratio of CD1 + DR + Langerhans cells/non-Langerhans CD1 - DR + epidermal cells changing from a mean of 0.82 at baseline to 1.92 at day 14. Thus, early in the course of therapy, CsA appears to be effective at clearing CD1 - DR + cells while leaving LC relatively intact in the epidermis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47242/1/403_2004_Article_BF00431054.pd
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