Simulation and experimental verification of W-band finite frequency selective surfaces on infinite background with 3D full wave solver NSPWMLFMA

We present the design, processing and testing of a W-band finite by infinite and a finite by finite Grounded Frequency Selective Surfaces (FSSs) on infinite background. The 3D full wave solver Nondirective Stable Plane Wave Multilevel Fast Multipole Algorithm (NSPWMLFMA) is used to simulate the FSSs. As NSPWMLFMA solver improves the complexity matrix-vector product in an iterative solver from O(N(2)) to O(N log N) which enables the solver to simulate finite arrays with faster execution time and manageable memory requirements. The simulation results were verified by comparing them with the experimental results. The comparisons demonstrate the accuracy of the NSPWMLFMA solver. We fabricated the corresponding FSS arrays on quartz substrate with photolithographic etching techniques and characterized the vector S-parameters with a free space Millimeter Wave Vector Network Analyzer (MVNA)

Comparison of different enrichment media for the isolation of Salmonella from naturally infected slaughter pigs

The present study aimed to assess the impact of different enrichment media, Reppaport-vassiliadis (RV) broth, Rappaport-Vassiliadis Soya (RVS) broth, Diagnostic semi-solid Salmonella (DIA) agar, Simple Method Salmonella (SMS) agar, Modified Semisolid Rappaport Vassiliadis (MSRV) agar and Mueller Kauffmann Tetrathionate novobiocin (MKTTn) broth, on the detection of Salmonella as well as on the isolated serotype and genotype

Quantification of the spread of Salmonella and the effect of 2 feed additives

The aim of this experiment was to quantify the spread of Salmonella Typhimurium in weaned piglets by calculating R0 values. In addition, the effect of 2 feed additives, AROMABIOTIC“ and Shiitake mushroom, on the spread of Salmonella Typhimurium was evaluated. Fifty-nine piglets were allocated to 4 groups: AROMABIOTIC“ (A, n=16), Shiitake mushroom (B, n=16), positive (C, n=16) and negative controls (D, n=11). Half of the piglets of group A, B and C were experimentally inoculated with Salmonella Typhimurium, other piglets were used as susceptibles. Based on Salmonella isolation in faecal swabs, R0 values (95% C.I.) were 4.26 (1.40-34.69), 1.83 (0.86-9.38) and 4.29 (1.09-13.71) for group A, B and C, respectively. None of the measured parameters did indicate significant differences between the groups. Mortality rate was high in all 4 groups, what makes it necessary to repeat the experiment

Effect of the use of organic acids in drinking water during the last two weeks prior to slaughter on salmonella shedding

In this study we investigated the effect of adding organic acids to the drinking water of finishing pigs two weeks prior to slaughter on the shedding and prevalence rate of Salmonella at slaughter. One hundred animals from 4 Belgian pig herds infected with Salmonella were included. Fifty of these ammals received drinking water supplemented with a mixture of different organic acids during 14 days prior to slaughter. Non-treated animals served as controls. Different samples were taken: contents of ileum and rectum, mesenteric lymph nodes and carcass swabs. All samples were submitted to Salmonella isolation using standard procedures. The results could not reveal a significant difference between both groups. This may be due to the limited power of the study (only 50 animals sampled in each group) or due to the fact that the treatment duration was insufficient to prove the benefit of the used organic acids

Exposure assessment of foodborne pathogens in pork in Belgium

The aim of this study was to assess the exposure of the most incident foodborne pathogens in the Belgian meat production chain. The prevalence of Salmonella, Campylobacter and Listeria monocytogenes were evaluated in carcasses (swabs), retail cuts, minced meat and meat products of pork. The investigation was made each year since 1997, using official methods from the Ministry of Public Health for Salmonella and Campylobacter and the Vidas Listeria monocytogenes method. More than 10 % of each matrix were contaminated with Salmonella. For minced meat and meat products, the contamination rate were respectively round 20 % and 3 – 6 % for Listeria monocytogenes. Under 5 % of minced meat samples were positive for Campylobacter. For minced meat, the contamination has also been assessed according to the location of sampling (agreed, low capacity establishments or retail level). The characterisation of bacterial species allows the comparison between meat and human isolates