Deterministic model to evaluate the impact of lactational treatment of subclinical mastitis due to coagulase-negative staphylococci

Coagulase-negative staphylococci (CNS) are the most frequently isolated bacteria from milk samples in several studies worldwide. Despite their relative frequency, specific measures aiming at their control are not well established. One possible measure to include in a control programme is lactational antimicrobial treatment. The decision to perform such treatment, as well as other actions on farm, should be based on the likelihood of financial return. A deterministic model was used to evaluate whether performing an antimicrobial treatment during the lactation for quarters infected with CNS was financially justifiable. Input variables for the impact of CNS on udder health were based on a previous study by the same authors and on available literature on the subject. Prices included in the model were based on 2009/2010 conditions in Portugal. The average result per antimicrobial treated quarter was a net loss of ?8·74. Performing a sensitivity analysis to evaluate how systematic variation of the input variables of the model would lead to outcome changes showed that variation in input variables nearly always led to a negative outcome, with the greatest variation in losses observed for variation in the length of treatment and milk withdrawal period (-?6·26 to -?8·49). The situations in which a net benefit was to be expected included the bulk tank somatic cell count decreasing to a level corresponding to a premium payment or to penalties being avoided, and the prevention of transmission of CNS in the milking parlour when the possibility of transmission was at its highest level. For most situations, lactational treatment of CNS subclinical mastitis was not financially justifiable.     

Spherical helical antenna with circular polarisation over a broad beam

A spherical helical antenna is proposed and its radiation characteristics are analysed using numerical methods and experimental measurements. Results for a 10 turn helix are presented. These results indicate that the spherical helix can provide circular polarisation over a wide beamwidth. The radiation patterns have a broad main beam, essentially no sidelobes, and low backlobe level.<>     

Simplified technique for detection of significant bacteriuria by microscopic examination of urine

A comparative study of microscopic examination of 10 microl (simplified loop technique) and 50 microl (traditional drop technique) of uncentrifuged Gram-stained urine specimens for detection of significant bacteriuria was carried out. The results demonstrated that the 10-microl loop technique can be used as an alternative to the 50-microl drop technique for presumptive diagnosis of urinary-tract infection in bacteriological practice, with the advantages of greater rapidity and ease of performance.     

Mechanochemical Synthesis of Magnesium Aluminate Spinel Powder at Room Temperature

MgAl₂O₄ spinel was successfully synthesized using a mechanochemical route that avoided the formation and calcination of its precursors at high temperatures. The method involved a single step in which γ-Al₂O₃–MgO, AlO(OH)–MgO, and α-Al₂O₃–MgO mixtures were milled at room temperature under air atmosphere. The formation of MgAl₂O₄ occurred faster with γ-Al₂O₃ than with AlO(OH) or α-Al₂O₃. After 140 h, the mechanochemical treatment of the γ-Al₂O₃–MgO mixture yielded 99% of MgAl₂O₄.     

Thermal stability and flammability studies of coated polymer powders using a plasma fluidized bed process

In this work, the thermal stability of organosilicon coatings, polyamide-6 powders and polyamide-6 clay nanocomposite powders coated with organosilicon are studied. The coatings were obtained from polymerization of 1.1.3.3-tetramethyldisiloxane (TMDS) monomer doped with oxygen using a cold remote nitrogen plasma (CRNP) process. A fluidized bed reactor using CRNP assisted polymerization was used to coat the polymer powders. The effect of oxygen addition to TMDS on the thermal stability was investigated. Oxygen addition to TMDS promotes the formation of more thermally stable coated polymers. In the case of the polyamide-6 clay nanocomposite, the Limiting Oxygen Index values were much improved. This shows that the deposits are effective fire retardant coatings.     

Staphylococcal strains involved in bovine mastitis are inhibited by Staphylococcus aureus antimicrobial peptides

The inhibitory activity of five bacteriocin (Bac)-producer strains of Staphylococcus aureus was tested against bacteria pathogenic for cattle. Sixty-five epidemiologically unrelated strains of Staph. aureus involved in bovine mastitis were used as indicators in an agar diffusion test. Bacteriocins produced by four strains could inhibit only a limited number of test organisms. However, all 65 indicator strains proved to be susceptible to the combined action of both bacteriocins encoded by pRJ9, a Bac plasmid found in strain A53. Therefore, the bacteriocins produced by this strain may represent new antimicrobial peptides with potential applications in the prevention and treatment of bovine mastitis.     

Structural analysis and optimisation of press brakes

A model of the bending process in Press Brakes is established using Timoshenko beam theory. Expressions for the workpiece bending error are derived that explicitly consider the influence of shape, dimensions and initial deformation of the machine structural components on its bending accuracy. The minimization of the bending error is formulated in terms of optimisation problems that are solved numerically using a genetic algorithm. The methodology presented in this paper permits the analysis of existing Press Brake design solutions, the optimisation of their performance and the development of new solutions.     

Blind signal separation: statistical principles

Blind signal separation (BSS) and independent component analysis (ICA) are emerging techniques of array processing and data analysis that aim to recover unobserved signals or “sources” from observed mixtures (typically, the output of an array of sensors), exploiting only the assumption of mutual independence between the signals. The weakness of the assumptions makes it a powerful approach, but it requires us to venture beyond familiar second order statistics, The objectives of this paper are to review some of the approaches that have been developed to address this problem, to illustrate how they stem from basic principles, and to show how they relate to each other     

Datapath BIST Insertion Using Pre-Characterized Area and Testability Data

There are several ways to insert Built-in Self-Test (BIST) circuitry on a circuit, each of them with particular consequences on area overhead, test application time and fault coverage. This paper presents a BIST insertion methodology applied to datapaths described at the RTL level that uses a database containing: (a) testability data of several types of test pattern generators (TPGs) and signature analyzers (SAs) when connected to several types of functional units and (b) area overhead due to the implementation by a datapath register of each type of those test resources. The availability of this database makes then possible to choose the best test resource types associated to each functional unit in a datapath, leading to good testability and area results.