1,705 research outputs found
Measures to reduce fine dust emission from poultry houses: reduction from broiler houses by ionization
In this study the effect was determined of a commercially available air ionization system on the reduction of airborne dust in a broiler house. Results showed a reduction, based on particle mass, of 36% and 10% for PM10 and PM2.5, respectivel
Options for dust reduction from poultry houses
Large poultry houses emit high amounts of fine dust (PM10) and in many cases they exceed the ambient air quality standard set by the EU. Technologies for PM10 reduction need to be developed on short term to minimize PM10 emissions from poultry houses. Studied options for dust reduction were: application of an oil film on the litter and application of an ionization system. Rapeseed oil was sprayed daily in a quantity of 8 to 24 ml/m2 in broiler houses and 20 ml/m2 in layer houses. The ionization system was applied in a broiler house and had a voltage difference of -30kV, with a current of approximately 0.7 mA. Daily emissions of PM10 particles were determined at regular intervals by measuring concentrations at the ventilation inlet and outlet and by measuring the airflow rate. For the oil system PM10 emission reductions were in the ranges of 55 – 85% in broilers and 25 – 40% in layers. The ionization system, applied in broilers, reduced PM10 emission on average by 36%
Maatregelen ter vermindering van fijnstofemissie uit de pluimveehouderij: optimalisatie van een oliefilmsysteem bij vleeskuikens = Measures to reduce fine dust emission from poultry: optimization of an oil spraying system for broilers
The effects of oil dose, spraying frequency and of technical optimizations of an oil spraying system on the reduction of fine dust were studied. Daily application of 8 to 15 ml of oil per m2 of bedding up from day 21 of the production cycle resulted in a 60% and 80% reduction of PM10 and PM2.5 emission, based on particle mass. Technical optimizations substantially reduced oil droplet
Prevalence of diabetes, metabolic syndrome and metabolic abnormalities in schizophrenia over the course of the illness: a cross-sectional study
BACKGROUND: Patients with schizophrenia are at high risk of developing metabolic abnormalities. METHOD: A prospective study focusing on metabolic disturbances in patients with schizophrenia, including an oral glucose tolerance test, is currently ongoing at our University Hospital and affiliate services. The prevalence of metabolic abnormalities at baseline was assessed in a cohort of 415 patients with schizophrenia. The sample was divided into 4 groups according to duration of illness: first-episode patients (<1.5 years), recent-onset patients (between 1.5 and 10 years), subchronic patients (between 10 and 20 years) and chronic patients (>20 years). RESULTS: Metabolic abnormalities were already present in first-episode patients, and considerably increased with increasing duration of illness. When compared to the general population matched for age and gender, much higher rates of the metabolic syndrome (MetS) and diabetes were observed for patients with schizophrenia. For MetS, the increase over time was similar to that of the general population. In contrast, the difference in the prevalence of diabetes in patients with schizophrenia and the general population dramatically and linearly increased from 1.6% in the 15–25 age-band to 19.2% in the 55–65 age-band. CONCLUSION: Thus, the current data suggest that on the one hand metabolic abnormalities are an inherent part of schizophrenic illness, as they are already present in first-episode patients. On the other hand, however, our results suggest a direct effect of the illness and/or antipsychotic medication on their occurence. The data underscore the need for screening for metabolic abnormalities in patients diagnosed with schizophrenia, already starting from the onset of the illness
Comparison of subgingival bacterial sampling with oral lavage for detection and quantification of periodontal pathogens by real-time polymerase chain reaction
Background: Saliva has been studied for the presence of subgingival pathogens in periodontitis patients. With the anaerobic culture technique, the discrepancy between salivary recovery and subgingival presence has been significant, which makes this approach not suitable for practical use in the microbial diagnosis of periodontitis patients. The real-time polymerase chain reaction (PCR) technique represents a very sensitive technique to detect and quantify bacterial pathogens. The aim of the study was to compare the presence and numbers of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythensis, Prevotella intermedia, and Micromonas micros in subgingival plaque and mouthwash samples by the anaerobic culture and real-time PCR techniques. Methods: Pooled subgingival plaque samples and 10-ml mouthwash samples were collected from 21 adult patients with periodontitis and analyzed by quantitative anaerobic culture and real-time PCR for A. actinomycetemcomitans, P. gingivalis, T. forsythensis, P. intermedia, and M. micros. Results: The detection frequency of A. actinomycetemcomitans, P. gingivalis, and T. forsythensis in subgingival plaque was identical by culture and real-time PCR and was higher for P. intermedia and M. micros by real-time PCR. The highest detection frequencies for the target bacteria were found in mouthwash samples by real-time PCR. The additional value of the real-time PCR to detect target bacteria was 38% for P. gingivalis, 73% for T. forsythensis, 77% for P. intermedia, and 71% for M. micros. The sensitivity to detect target species in mouthwash by real-time PCR was 100% for all test species except for P. intermedia (93.8%). Conclusions: Rapid detection and quantification of periodontal pathogens in mouthwash samples are possible by real-time PCR. The procedure is significantly less time-consuming than subgingival sampling with paper points. This approach to detect major periodontal pathogens in mouthwash samples may simplify microbial diagnosis in periodontitis patients and may be used to monitor periodontal treatment
A morphological algorithm for improving radio-frequency interference detection
A technique is described that is used to improve the detection of
radio-frequency interference in astronomical radio observatories. It is applied
on a two-dimensional interference mask after regular detection in the
time-frequency domain with existing techniques. The scale-invariant rank (SIR)
operator is defined, which is a one-dimensional mathematical morphology
technique that can be used to find adjacent intervals in the time or frequency
domain that are likely to be affected by RFI. The technique might also be
applicable in other areas in which morphological scale-invariant behaviour is
desired, such as source detection. A new algorithm is described, that is shown
to perform quite well, has linear time complexity and is fast enough to be
applied in modern high resolution observatories. It is used in the default
pipeline of the LOFAR observatory.Comment: Accepted for publication in A&
Bepaling van de verhouding marien-fluviatiel slib in de beneden Zeeschelde in het voorjaar van 2004
- …