931 research outputs found
Development of prevention and treatment strategies for parasites in poultry
Parasitic infections are likely to be more important in organic and other free-range hens than in birds kept indoors. Several workpackages of QLIF aim at improving prevention and therapy of helminth (Ascaridia galli and Heterakis gallinarum) and arthropod (Dermanyssus gallinae) parasites of laying hens. This paper is a summary of the work undertaken in the first 3 years of QLIF
Run management for organic layers
Layer runs are often bare and loaded with nutrients and with infectious stages of helminths. Various management strategies are recommended in order to better distribute the hens in the run, thereby preventing local accumulation of droppings and related problems. However, little is known about the impact of those strategies.
A series of on farm experiments has been performed in order to test the effects of flock size and of artificial structures on the dispersal of the hens in the run. Further studies evaluated the effects of mowing and run size as well as rotational use of runs on turf quality, nutrient load in the soil and on the infection of the hens with internal parasites.
As a summary, introducing structures or applying a rotational management scheme improves run use and facilitates mowing, thus improving turf quality in the run in front of the henhouse. However, the expected reduction of helminth infections and nutrient accumulation has not been observed
Effect of Impurities on the Initiation of the Methanol-to-Olefins Process: Kinetic Modeling Based on Ab Initio Rate Constants
The relevance of a selection of organic impurities for the initiation of the MTO process was quantified in a kinetic model comprising 107 elementary steps with ab initio computed reaction barriers (MP2:DFT). This model includes a representative part of the autocatalytic olefin cycle as well as a direct initiation mechanism starting from methanol through CO-mediated direct C–C bond formation. We find that the effect of different impurities on the olefin evolution varies with the type of impurity and their partial pressures. The reactivity of the considered impurities for initiating the olefin cycle increases in the order formaldehyde < di-methoxy methane < CO < methyl acetate < ethanol < ethene < propene. In our kinetic model, already extremely low quantities of impurities such as ethanol lead to faster initiation than through direct C–C bond formation which only matters in complete absence of impurities. Graphic Abstract: [Figure not available: see fulltext.
Wirken sich Auslauf- und Einstreumanagement auf den Wurmbefall von Legehennen aus?
The aim of our experiments was to investigate the transmission and infectivity of the
two main helminth parasites of poultry (Ascaridia galli and Heterakis gallinarum) under
different run and litter management regimes. In experiment (a) two stocking rates were
simulated in outdoor runs and the effect of a simple management practice (mowing)
on helminth transmission was studied during two subsequent flocks. Stocking rate
seemed not to change helminth transmission patterns and repeated mowing of runs
did not reduce helminth infections. Lower stocking rates led to a substantial improvement
of the run vegetation. In experiment (b) two litter management regimes (replace
or add litter material) were compared to unmanaged litter with regard to parasitological
parameters and water content of the litter. The regimes had no significant effect on
water content or on parasitological parameters. These results suggest that positive
effects of run and litter management regimes on helminth infections of laying hens are
often overestimated in practice
The years after: a concept of the psychological integration of childhood cancer
Goals of work: To define and measure the psychological integration of childhood cancer experiences into a personal biography and to explore the association between integration with illness-related factors and psychosocial conditions. Patients and methods: Analysis of cancer survivors' narratives on the course of their illness was used to measure integration. Psychosocial condition, body concepts, health locus of control, and illness-related distress were evaluated by questionnaires. Illness factors were assessed by reviewing hospital case notes and sociodemographic factors by a structured interview. Of 72 eligible subjects contacted, 60 agreed to participate. Main results: High inter-rater correlations established the reliability of the concept of testing integration by narrative analysis. Subjects with good psychological integration of the experience of cancer saw chance as having less to do with illness and health, and perceived illness and therapy retrospectively as more distressing than survivors with poor integration. In contrast, integration did not correlate with distress evoked by present feelings toward illness and therapy or by thoughts of a relapse. Conclusions: Successful integration of the experience of cancer may be associated with the ability to accept painful feelings and to allow them to emerge, and with a readiness to accept responsibility in relation to health and medical care. Assisting young cancer patients and their families to create and maintain their personal narratives of the experience of illness is an important clinical task for all professionals working in paediatric oncolog
Distribution of infection with gastro-intestinal nematodes in different groups of dairy goats in Switzerland and its influence on milk production
The aim of this field study was to investigate interactions between gastro-intestinal nematode (GIN) infection, milk performance and age in goats in order to identify animal groups with higher susceptibility to GIN. On 3 farms (farm A: n = 29, farm B: n = 33, farm C: n = 117 milking goats) fecal egg count reduction tests (FECRT) were performed in summer. All 179 milking goats were enrolled in FECRT and individual milk performance was recorded before and after FEC for FECRT. Furthermore, in early summer and autumn bulk fecal samples were cultured for every farm and GIN genera were determined
Theoretical investigation of the olefin cycle in H-SSZ-13 for the ethanol-to-olefins process using ab initio calculations and kinetic modeling
The formation of the hydrocarbon pool (HCP) in the ethanol-to-olefins (ETO) process catalyzed by H-SSZ-13 is studied in a kinetic model with ab initio computed reaction barriers. Free energy barriers are computed using density functional theory (DFT) and post-Hartree–Fock methods with a complete basis set extrapolation applied to a hierarchy of periodic and cluster models. The kinetic model includes ethanol (EtOH) dehydration to ethene as well as olefin ethylations up to hexene isomers and the corresponding cracking reactions. Ethylation of ethene and of products thereof leads only to even-numbered olefins, while cracking can lead to propene and thus initiate the formation of olefins with an odd number of carbon atoms. During EtOH dehydration at 473.15 K we observe diethyl ether (DEE) formation for a short period of time where the DEE selectivity decreases monotonically with increasing EtOH conversion. At 673.15 K we find that EtOH dehydration occurs much faster than ethylation of the formed ethene, which takes considerably longer due to higher free energy barriers. Hexene isomers form on the same time scale as butene, where branched isomers are favored with 2-methyl-pentene isomers contributing most to the formation of propene through cracking. As in the methanol-to-olefins (MTO) process, the most relevant alkylation pathway is the stepwise mechanism via surface alkoxy species (SAS) on the zeolite catalyst. A comparison of ethylation with methylation barriers of up to heptene isomers forming nonene and octene isomers, respectively, shows that ethylation barriers are lower by around 11 kJ mol on average
Anharmonic Correction to Adsorption Free Energy from DFT-Based MD Using Thermodynamic Integration
SPECT/CT tracer uptake is influenced by tunnel orientation and position of the femoral and tibial ACL graft insertion site
Purpose: SPECT/CT is a hybrid imaging modality, which combines a 3D scintigraphy (SPECT) and a conventional computerised tomography (CT). SPECT/CT allows accurate anatomical localisation of metabolic tracer activity. It allows the correlation of surgical factors such as tunnel position and orientation with mechanical alignment, clinical outcome and biological factors. The purpose of this study was to investigate whether the SPECT/CT tracer uptake (intensity and distribution) correlates with the stability and laxity of the knee joint and the position and orientation of the tibial and femoral tunnels in patients after anterior cruciate ligament (ACL) reconstruction. Methods: A consecutive series of knees (n = 66), with symptoms of pain and/or instability after ACL reconstruction were prospectively evaluated using clinical examination and 99mTc-HDP-SPECT/CT. Clinical laxity testing was performed using the Rolimeter (Ormed, Freiburg, Germany) including Lachman testing (0-2 mm, 3-5 mm, 6-10 mm, >10 mm), anterior drawer test (0-2 mm, 3-5 mm, 6-10 mm, >10 mm), pivot shift test (positive versus negative) and patient-based subjective instability (yes versus no). For analysis of SPECT/CT tracer uptake a previously validated SPECT/CT localisation scheme consisting of 17 tibial, nine femoral and four patellar regions on standardised axial, coronal, and sagittal slices was used. The tracer activity on SPECT/CT was localised and recorded using a 3D volumetric and quantitative analysis software. Mean, standard deviation, minimum and maximum of grading for each area of the localisation scheme were recorded. The position and orientation of the tibial and femoral tunnel was assessed using a previously published method on 3D-CT. Results: Correlation of instability, pivot shift as well as clinical laxity testing with 99mTc-HDP-SPECT/CT tracer uptake intensity and distribution showed no significant correlation. 99mTc-HDP-SPECT/CT tracer uptake correlated significantly with the position and orientation of the ACL graft. A more horizontal femoral graft position showed significantly increased tracer uptake within the superior and posterior femoral regions. A more posteriorly-placed femoral insertion site showed significantly more tracer uptake within the femoral and tibial tunnel regions. A more vertical or a less medial tibial tunnel orientation showed significant increased uptake within the tibial and femoral tunnel regions. A more anterior tibial tunnel position showed significantly more tracer uptake in the femoral and tibial tunnel regions as well as the entire tibiofemoral joint. Conclusions: SPECT/CT tracer uptake intensity and distribution showed a significant correlation with the femoral and tibial tunnel position and orientation in patients with symptomatic knees after ACL reconstruction. No correlation was found with stability or clinical laxity. SPECT/CT tracer uptake distribution has the potential to give us important information on joint homeostasis and remodelling after ACL reconstruction. It might help to predict ACL graft failure and improve our surgical ACL reconstruction technique in finding the optimal tunnel and graft position and orientatio
In Search of Benchmarking for Mortality Following Multiple Trauma: A Swiss Trauma Center Experience
Background: The manifestations associated with non-survival after multiple trauma may vary importantly between countries and institutions. The aim of the present study was to assess the quality of performance by comparing actual mortality rates to the literature. Methods: The study involved evaluation of a prospective consecutive multiple trauma cohort (injury severity score, ISS>16) primarily admitted to a university hospital. Univariate and multivariate testing of routine parameters and scores, such as the Trauma and Injury Severity Score (TRISS), was used to determine their predictive powers for mortality. Results: The 30-day mortality of 22.8% (n=54) exactly matched predicted TRISS versions of Champion or the Major Trauma Outcome Study for our 237 multiple trauma patients (42.8±20.9years; ISS 29.5±11.5). Univariate analysis revealed significant differences between survivors and non-survivors when compared for age, ISS, Glasgow coma scale (GCS), pulse oximeter saturation (SapO2), hemoglobin, prothrombin time, and lactate. In multivariate analysis, age, ISS, and GCS (P<0.001 each) functioned as major independent prognostic parameters of both 24h and 30-day mortality. Various TRISS versions hardly differed in their precision (area under the curve [AUC] 0.83-0.84), but they did differ considerably in their level of requirement, with the TRISS using newer National Trauma Data Bank coefficients (NTDB-TRISS) offering the highest target benchmark (predicted mortality 13%, Z value -5.7) in the prediction of 30-day mortality. Conclusions: Because of the current lack of a single, internationally accepted scoring system for the prediction of mortality after multiple trauma, the comparison of outcomes between medical centers remains unreliable. To achieve effective quality control, a practical benchmarking model, such as the TRISS-NTDB, should be used worldwid
- …