The Nelson and Winter Models RevisitedPrototypes for Computer-Based Reconstruction of Schumpeterian Competition

The report deals with the reconstruction and further development of the models of industrial dynamics developed by Nelson and Winter and summarised in their famous 1982-book. The basic idea underlying the Nelson and Winter models is that a verbal account of Schumpeterian competition can naturally be transformed into a description of a computational process in which firms not only make short-term production decisions and investment decisions but also performs a search for new technologies. The latter search is successful in a probabilistic manner, and its successes and failures determine an evolutionary process of the industry. Although the simulation models of Nelson and Winter have played a central role the ‘take-off’ of evolutionary economics, they have never been fully documented and their differences have never been explored. The resulting problems are obvious for students who start from Nelson’s and Winter’s most famous accounts, but even for researchers with a full collection of the underlying research papers, the situation is quite confusing. The report tries to make things easier by presenting overviews of the structure of Nelson and Winter models as well as fully implemented versions of their simulation models – especially NELWIN78 based on ch. 13 of the 1982-book and NELWIN77 based on ch. 12. The report furthermore presents a computer-based environment (implemented in MAPLE V Rev2) for revision of the models and for analysis of the overwhelming number of data resulting from simulation runs.Evolutionary economic modelling, simulation of industrial dynamics, Schumpeterian competit

Performance and diarrhoea in piglets following weaning at seven weeks of age: Challenge with E. coli O 149 and effect of dietary factors

Four dietary factors (ad libitum versus feed restriction, control versus protein restriction at ad libitum feeding, control versus inclusion of lupine as a protein source at ad libitum feeding, and control versus extra vitamin E at ad libitum feeding) were tested in four separate experiments for the effect on diarrhoea. To introduce a diarrhoea-like condition, half of the piglets were challenged with an inoculation of an E. coli O 149 dose of 1 x 108 colony forming units on day two and three after weaning (day of weaning = day one). All piglets were susceptible since the dams were tested mono-zygotic susceptible to the attachment site of E. coli O 149 in the intestines. Each of the four experiments included 32 piglets from 4 sows. The design was 2 x 2 factorial with dietary factor and E. coli O 149 challenge as the two factors, each at two levels. The piglets were housed individually during the experiment which lasted for 10 days from weaning at 7 weeks of age. The daily recordings included feed intake, weight and faeces score (from 1 = firm and solid to 6 = yellow and watery). Faeces from days 2 to 5 were tested for E. coli strains. In addition, blood was sampled and serum was analysed for E. coli antibodies, IgG and IgM. Generally the E. coli challenge had no effect on growth and feed intake whereas faeces score and number of faeces haemolytic bacteria increased and faeces dry matter decreased. Feed restriction decreased the weight gain while faeces characteristics were unaffected. An analysis including all four experiments revealed that a feed intake of less than 200 g day one after weaning seems to be associated with a relatively high incidence of a post-weaning diarrhoea-like condition. Protein restriction decreased faeces score and increased faeces dry matter while weight gain tended to decrease. Inclusion of lupine affected neither weight gain nor faeces characteristics. Extra vitamin E did not affect weight gain while faeces dry matter decreased, and faeces score and number of faecal haemolytic bacteria increased. The dietary treatments had no effect on the immunological responses. In conclusion, the studied dietary factors could not alleviate a diarrhoea-like condition and at the same time maintain the growth rate. Furthermore, the results indicate that performance can be improved if piglets achieve a daily feed intake of at least 200 g from day one after weaning

A novel approach to probe host-pathogen interactions of bovine digital dermatitis, a model of a complex polymicrobial infection

Background: Polymicrobial infections represent a great challenge for the clarification of disease etiology and the development of comprehensive diagnostic or therapeutic tools, particularly for fastidious and difficult-to-cultivate bacteria. Using bovine digital dermatitis (DD) as a disease model, we introduce a novel strategy to study the pathogenesis of complex infections. Results: The strategy combines meta-transcriptomics with high-density peptide-microarray technology to screen for in vivo-expressed microbial genes and the host antibody response at the site of infection. Bacterial expression patterns supported the assumption that treponemes were the major DD pathogens but also indicated the active involvement of other phyla (primarily Bacteroidetes). Bacterial genes involved in chemotaxis, flagellar synthesis and protection against oxidative and acidic stress were among the major factors defining the disease. Conclusions: The extraordinary diversity observed in bacterial expression, antigens and host antibody responses between individual cows pointed toward microbial variability as a hallmark of DD. Persistence of infection and DD reinfection in the same individual is common; thus, high microbial diversity may undermine the host's capacity to mount an efficient immune response and maintain immunological memory towards DD. The common antigenic markers identified here using a high-density peptide microarray address this issue and may be useful for future preventive measures against DD.Fil: Marcatili, Paolo. Technical University of Denmark; DinamarcaFil: Nielsen, Martin W.. Technical University of Denmark; DinamarcaFil: Sicheritz Ponten, Thomas. Technical University of Denmark; DinamarcaFil: Jensen, Tim K.. Technical University of Denmark; DinamarcaFil: Schafer Nielsen, Claus. Schafer-N ApS; DinamarcaFil: Boye, Mette. Hospital of Southern Jutland; DinamarcaFil: Nielsen, Morten. Technical University of Denmark; Dinamarca. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas ; ArgentinaFil: Klitgaard, Kirstine. Technical University of Denmark; Dinamarc

Head Wave Correlations in Ambient Noise

Ambient ocean noise is processed with a vertical line array to reveal coherent time-separated arrivals suggesting the presence of head wave multipath propagation. Head waves, which are critically propagating water waves created by seabed waves traveling parallel to the water-sediment interface, can propagate faster than water-only waves. Such eigenrays are much weaker than water-only eigenrays, and are often completely overshadowed by them. Surface-generated noise is different whereby it amplifies the coherence between head waves and critically propagating water-only waves, which is measured by cross-correlating critically steered beams. This phenomenon is demonstrated both experimentally and with a full wave simulation

E-vitamin til økologiske smågrise efter fravænning

Virkningen af ekstra E vitamin på fravænningsdiarré blev undersøgt i tre økologiske svinebesætninger. Ved fravænning blev grisene i disse besætninger delt i to hold hvoraf det ene hold fik ekstra naturligt E vitamin i foderet (100 mg/kg), mens kontrolholdet fik samme foderblanding uden ekstra E vitamin. Foderblandingerne i de tre besætninger havde i forvejen et ret højt E vitamin indhold (55-150 mg alfa-tocoferol pr. kg). Gødningskarakter og vægt blev registeret på fravænningsdagen samt 5 dage og ca. 5 uger efter fravænning. Der var stor forskel i graden af diarré i de tre besætninger, men hverken i to problemfrie besætninger eller i en besætning med udbredt fravænningsdiarré havde den ekstra E vitamin nogen virkning på tilvækst og diarré. Foderblandingerne i de tre besætninger levede op til den nye norm for E vitamin (130 mg/FE, hvis E vitaminet tildeles som syntetisk E vitamin), og det er sandsynligt, at ekstra E vitamin udover denne norm er uden virkning. Fravænningsdiarré er i øvrigt et multifaktorielt problem hvor man udover ernæringsmæssige faktorer som E vitamin også skal være opmærksom på det generelle sygdomspres, hygiejne og stress m.m

Biopsy-based optimization and calibration of a signal-intensity-ratio-based MRI method (1.5 Tesla) in a dextran-iron loaded mini-pig model, enabling estimation of very high liver iron concentrations

OBJECTIVE: Magnetic resonance imaging (MRI)-based techniques for non-invasive assessing liver iron concentration (LIC) in patients with iron overload have a limited upper measuring range around 35 mg/g dry weight, caused by signal loss from accelerated T1-, T2-, T2* shortening with increasing LIC. Expansion of this range is necessary to allow evaluation of patients with very high LIC. AIM: To assess measuring range of a gradient-echo R2* method and a T1-weighted spin-echo (SE), signal intensity ratio (SIR)-based method (TE = 25 ms, TR = 560 ms), and to extend the upper measuring range of the SIR method by optimizing echo time (TE) and repetition time (TR) in iron-loaded minipigs. METHODS: Thirteen mini pigs were followed up during dextran-iron loading with repeated percutaneous liver biopsies for chemical LIC measurement and MRIs for parallel non-invasive estimation of LIC (81 examinations) using different TEs and TRs. RESULTS: SIR and R2* method had similar upper measuring range around 34 mg/g and similar method agreement. Using TE = 12 ms and TR = 1200 ms extended the upper measuring range to 115 mg/g and yielded good method of agreement. DISCUSSION: The wider measuring range is likely caused by lesser sensitivity of the SE sequence to iron, due to shorter TE, leading to later signal loss at high LIC, allowing evaluation of most severe hepatic iron overload. Validation in iron-loaded patients is necessary

Novel mouse model of murine cytomegalovirus-induced adaptive NK cells

NK cells are important mediators of viral control with the capacity to form adaptive immune features following infection. However, studies of infection-induced adaptive NK cells require adoptive cell transfer to lower the precursor frequency of Ag-specific NK cells, potentially limiting the diversity of the NK cell response. In seeking an unmanipulated model to probe the adaptive NK cells, we interrogated a wide range of Collaborative Cross (CC) inbred mice, inbred mouse strains that exhibit broad genetic diversity across strains. Our assessment identified and validated a putative ideal CC strain, CC006, which does not require manipulation to generate and maintain adaptive NK cells. Critically, CC006 mice, in contrast to C57BL/6 mice, are capable of developing enhanced NK cell-mediated protective responses to murine CMV infection following m157-mediated vaccination. This work both furthers our understanding of adaptive NK cells and demonstrates the utility of CC mice in the development and interrogation of immunologic models