212 research outputs found
A Network of Portable, Low-Cost, X-Band Radars
Radar is a unique tool to get an overview on the weather situation, given its high spatio- temporal resolution. Over 60 years, researchers have been investigating ways for obtaining the best use of radar. As a result we often find assurances on how much radar is a useful tool, and it is! After this initial statement, however, regularly comes a long list on how to increase the accuracy of radar or in what direction to move for improving it. Perhaps we should rather ask: is the resulting data good enough for our application? The answers are often more complicated than desired. At first, some people expect miracles. Then, when their wishes are disappointed, they discard radar as a tool: both attitudes are wrong; radar is a unique tool to obtain an excellent overview on what is happening: when and where it is happening. At short ranges, we may even get good quantitative data. But at longer ranges it may be impossible to obtain the desired precision, e.g. the precision needed to alert people living in small catchments in mountainous terrain. We would have to set the critical limit for an alert so low that this limit would lead to an unacceptable rate of false alarm
Use of injectable transponders for the identification and traceability of pigs
Individual identification in pigs is a key point for management, traceability and trade control. The aim of this experiment was to study retention rate and functionality of electronic identification systems in pigs, injected in different sites, to evaluate traceability of animals and highlight histopathological alterations of tissues in different inoculation sites. A total of 60 crossbred piglets were used to compare different transponder inoculation sites. One group (15 piglets) was identified only by plastic ear tags; and three groups were identified by passive injectable transponders (PIT) with different inoculation sites. Pigs were slaughtered in two different moments, in order to evaluate injection sites, macroscopically and histologically, either 50 days after injection or at a normal slaughtering weight. In general, no apparent animal health problems were observed the day after the injection or during the control readings performed during the experiment. Intraperitoneal localization gave excellent results in term of readability until the slaughter time. Transponders at the slaughter line were always recovered in the viscera tray because they were found loose in the peritoneal cavity. In some cases, they were found on the carcasses, attached to the peritoneum. In those cases a sample of peritoneal tissue was collected for histological examination. A reparative chronic reaction with moderate and multifocal fibrosis and neoformed vessels associated to multifocal and mild lymphoplasmacytic infiltrate were detected. In one case (6.7%) the transponder was found on the visceral side of the liver and the histological examination highlighted a localized superficial hepatic atrophy by compression. Retroauricolar site of injection gave lower readability results because 2 transponders (13.3%) were no more readable during the first month after injection. No lesions were found with this inoculation site. PIT injected in the perineal region were operative until slaughter time. Recovery procedures at the slaughter house were simple for animals slaughtered at a low weight, but much more difficult in the case of heavy pigs. Moreover, in three cases (20%), PITs were no more in the subcutaneous tissue but they had an intramuscular localization. The histological examination of the muscles revealed a chronic reparative process. In our experiment, injectable transponders in the intraperitoneal position provided the best identification system for pigs. Histopathological examination revealed only local reparative processes in the tissues interested by PIT contact, and no other pathological changes
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