Frequency and etiology of calf losses and calf diseases before weaning in cow-calf farms. II. Microbiological and parasitological diagnoses in diarrheic calves]

Diarrhea is the most frequently diagnosed disease in Swiss cow-calf farms. During an longitudinal study conducted in 105 cow-calf farms in Switzerland in 1993-95, blood and fecal samples were collected from diarrheic calves and from calves that died because of diarrhea. Campylobacter spp. were detected in 42%, E. coli (VTEC) in 32%, rotavirus in 33%, coronavirus in 13%, coccidia in 43% and helminths in 8% of the cases. In some samples Yersinia pseudotuberculosis were isolated. The BVD-virus antigen was not detected in any of the calves examined. In most cases concurrent infection with several enteropathogens was diagnosed. Specific causes of diarrhea were therefore difficult to establish. The bacteriological findings of this study have implication for food safety: VTEC, Campylobacter spp. Yersinia spp. and cryptosporidia are considered as potential causes on zoonoses.     

Dielectric modeling of transmittance spectra of thin ZnO:Al films

A dielectric model comprising band gap transitions and free electron excitations (Drude model) is successfully applied to simulate transmittance spectra of ZnO films doped with 0.5%, 1% and 2% Al. The Drude formula contains a frequency-dependent damping term in order to get a good fit in the visible spectral region. Useful physical parameters obtained from the fit are electron density and mobility within the grains, film thickness, band gap and refractive index. The optically determined film thickness agrees with that obtained with the stylus method within 2%. The optically determined electronic parameters are compared with those obtained by electrical measurements. Contrary to thin In₂O₃:Sn films, the Drude mobility inside the grains is similar to the direct current Hall mobility indicating more perfect film growth without forming pronounced grain boundaries. Maximum value is 35 cm²/V s. The effective electron mass is estimated to be about 0.6 of the free electron mass. The refractive index at 550 nm decreases with increasing electron density.     

Chladnis Beiträge zur Raumakustik

A lot of publications on the acoustics of theatres and churches were published around the turn of the 18th to the 19th century.The authors were architects who were interested in acoustical problems. Chladni was the first physicist who published on the acoustics of rooms, he introduced the term “reverberation” into this field. His publications on this subject are reviewed. They have been the basis for the great progress of room acoustics since 1900.

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Zum 250. Geburtstag des Gelehrten     

Conditions of Liquid Steel Treatment for Near Net‐Shape Casting Processes

Slab casting for hot rolled steel and strip casting using the twin roll casting (TRC) method are compared in terms of inclusions evolution. There are differences of the processes, mainly the use of casting flux in CC of slabs, or pool shapes and sizes in terms of TRC, particularly when roll diameters vary. The inclusion evolution of alumina in a low carbon steel grade was estimated. By modelling particle growth rate, coagulation and deposition, an ‘agglomeration index’ was created to describe the probability of clogging in the SEN. Similarly the growth of secondary alumina precipitation during cooling of the melt in the pool by Stokes collision and turbulent collision was estimated in terms of forming large particles which are able to float‐up. Influences of melt superheat or caster size were taken into account.     

A Numerical Treatment of the rf SQUID: I. General Properties and Noise Energy

We investigate the characteristics and noise performance of rf Superconducting Quantum Interference Devices (SQUIDs) by solving the corresponding Langevin equations numerically and optimizing the model parameters with respect to noise energy. After introducing the basic concepts of the numerical simulations, we give a detailed discussion of the performance of the SQUID as a function of all relevant parameters. The best performance is obtained in the crossover region between the dispersive and dissipative regimes, characterized by an inductance parameter β′ _L ≡2π LI ₀/Φ ₀≈1; L is the loop inductance, I ₀ the critical current of the Josephson junction, and Φ ₀ the flux quantum. In this regime, the lowest (intrinsic) values of noise energy are a factor of about 2 above previous estimates based on analytical approaches. However, several other analytical predictions, such as the inverse proportionality of the noise energy on the tank circuit quality factor and the square of the coupling coefficient between the tank circuit and the SQUID loop, could not be well reproduced. The optimized intrinsic noise energy of the rf SQUID is superior to that of the dc SQUID at all temperatures. Although for technologically achievable parameters this advantage shrinks, particularly at low thermal fluctuation levels, we give examples for realistic parameters that lead to a noise energy comparable to that of the dc SQUID even in this regime.      

Modern Teaching and Training in Metallurgical Engineering

This contribution deals with advanced educational technologies needed to equip customers from higher education institutions, research and industry with efficient tools supporting their work and operating new skills‐training methods. The challenges are reducing the training costs, improving quality and increasing the number of graduates in engineering departments. The concept of a Virtual Lab based on the combination of various teaching methods and tools is presented. Principles of mathematisation in metallurgical education and training are discussed. An example of online course designed in the form of Virtual Lab is demonstrated.     

Efficient identification of point mutations by automated DNA sequencing of artificial heterozygote samples

Polyglandular autoimmune syndrome (PGAS) type 2 (Schmidt syndrome) is characterized by the association of primary adrenocortical insufficiency with autoimmune thyroid disease, and/or insulin-dependent diabetes mellitus (IDDM). In this report we describe the occurrence of two episodes of post-partum thyroiditis (PPT) after a first and second pregnancy as well the development acutely of adrenal insufficiency after a second pregnancy. A family history of autoimmune thyroid disease and IDDM as well as positive antiadrenal and antithyroid antibodies and HLA typing is evidence for an underlying polyendocrine autoimmune syndrome. This case report provides further evidence that the immune system that is suppressed in pregnancy to tolerate the fetal allograft can rebound post-partum to unmask polyendocrine autoimmune disorders such as adrenalitis and PPT in susceptible women.     

Influence of Threshold Stress on the Estimation of the Weibull Statistics

The influence of threshold stress on the estimation of the Weibull statistics is discussed in terms of the Akaike information criterion. Numerical simulations show that, if sample data are limited in number and threshold stress is not too large, the two-parameter Weibull distribution is still a preferred choice. For example, the fit of strength data of glass and ceramics to the two- and three-parameter Weibull distributions is compared.