Harnessing nonlinearity: predicting chaotic systems and saving energy in wireless communication   总被引：2，自引：0，他引：2  

Jaeger H  Haas H 《Science (New York, N.Y.)》2004,304(5667):78-80

We present a method for learning nonlinear systems, echo state networks (ESNs). ESNs employ artificial recurrent neural networks in a way that has recently been proposed independently as a learning mechanism in biological brains. The learning method is computationally efficient and easy to use. On a benchmark task of predicting a chaotic time series, accuracy is improved by a factor of 2400 over previous techniques. The potential for engineering applications is illustrated by equalizing a communication channel, where the signal error rate is improved by two orders of magnitude.  相似文献   

A Simple Aid for the Cannulation of Small Blood Vessels     

Haas E  Goldblatt H 《Science (New York, N.Y.)》1948,108(2798):166

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A SIMPLE METHOD OF MEASURING PHOTOSYNTHESIS     

Osterhout WJ  Haas AR 《Science (New York, N.Y.)》1918,47(1217):420-422

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The genome sequence of Trypanosoma cruzi, etiologic agent of Chagas disease     

El-Sayed NM  Myler PJ  Bartholomeu DC  Nilsson D  Aggarwal G  Tran AN  Ghedin E  Worthey EA  Delcher AL  Blandin G  Westenberger SJ  Caler E  Cerqueira GC  Branche C  Haas B  Anupama A  Arner E  Aslund L  Attipoe P  Bontempi E  Bringaud F  Burton P  Cadag E  Campbell DA  Carrington M  Crabtree J  Darban H  da Silveira JF  de Jong P  Edwards K  Englund PT  Fazelina G  Feldblyum T  Ferella M  Frasch AC  Gull K  Horn D  Hou L  Huang Y  Kindlund E  Klingbeil M  Kluge S  Koo H  Lacerda D  Levin MJ  Lorenzi H  Louie T  Machado CR  McCulloch R 《Science (New York, N.Y.)》2005,309(5733):409-415

Whole-genome sequencing of the protozoan pathogen Trypanosoma cruzi revealed that the diploid genome contains a predicted 22,570 proteins encoded by genes, of which 12,570 represent allelic pairs. Over 50% of the genome consists of repeated sequences, such as retrotransposons and genes for large families of surface molecules, which include trans-sialidases, mucins, gp63s, and a large novel family (>1300 copies) of mucin-associated surface protein (MASP) genes. Analyses of the T. cruzi, T. brucei, and Leishmania major (Tritryp) genomes imply differences from other eukaryotes in DNA repair and initiation of replication and reflect their unusual mitochondrial DNA. Although the Tritryp lack several classes of signaling molecules, their kinomes contain a large and diverse set of protein kinases and phosphatases; their size and diversity imply previously unknown interactions and regulatory processes, which may be targets for intervention.  相似文献   

Genetic parameters for clinical mastitis in the first three lactations of Dutch Holstein cattle     

Bloemhof S  de Jong G  de Haas Y 《Veterinary microbiology》2009,134(1-2):165-171

The first breeding value for udder health of a bull is based on the performance of his daughters in their first lactation. However, clinical mastitis (CM) is not a problem in first lactation only. Therefore, the objective of this study was to estimate genetic parameters for CM and somatic cell count (SCC) for the first three lactations of Dutch Holstein cattle. Data from 250 Dutch herds recording CM were used to quantify the genetic variation of CM in parity 1, 2, and 3, respectively. The dataset contained 35,379 lactations from 21,064 animals of different parities. Test-day SCC was available from all lactations. Somatic cell counts were log-transformed to somatic cell scores (SCS) and averaged over test-day records between 5 and 335, 5 and 150, and 151 and 335 days in milk. Variance components for CM and SCS were estimated using a sire-maternal grandsire model. The heritability for CM was approximately 3% in all parities. Genetic correlations between CM in consecutive lactations were high (0.9), but somewhat lower between parity 1 and 3 (0.6). All genetic correlations between CM and SCS were positive, implying that genetic selection on lower SCC will reduce CM-incidence. Estimated genetic correlations were stronger for SCS in the first half of lactation than in the second half of lactation. Selection indices showed that most progress could be achieved when treating CM in parity 1, 2, and 3 as different traits and by including SCS between 5 and 150 days in the udder health index.  相似文献   

Animal therapy over the ages: 10. Zoogenous therapy. Extracts, excretions, and secretions     

Haas KB 《Veterinary heritage : bulletin of the American Veterinary History Society》2003,26(2):33-35

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Implementation of two-step vaccination in the control of bovine viral diarrhoea (BVD)     

Moennig V  Eicken K  Flebbe U  Frey HR  Grummer B  Haas L  Greiser-Wilke I  Liess B 《Preventive veterinary medicine》2005,72(1-2):109-14; discussion 215-9

Bovine viral diarrhoea (BVD) control/eradication programmes based on the test and removal of persistently infected cattle without use of vaccination were first introduced by the Scandinavian countries in the early 1990s. Within the last 10 years the programmes have proven to be very successful and have served as a blueprint for several other European regions. However, in areas with high cattle densities, intense animal trade and high BVD prevalence this control approach is risky, because there is a high probability that herds, which have been cleared of persistently infected (PI) animals and have become partly or fully susceptible to reintroduction of the virus, will come in contact with a BVD virus (BVDV) infected animal. A combination of the test and removal strategy with subsequent systematic vaccination of cattle could overcome this problem. The goals of vaccination in such a programme is protection against reintroduction of BVDV into herds free from PI cattle and foetal protection of pregnant animals accidentally exposed to the virus. Two-step vaccination is based on the use of inactivated BVDV-1 vaccine for priming followed by a live attenuated vaccine booster 4 weeks later. The immune response elicited by such a vaccination scheme has proven to be long lasting and foetal infection after challenge with BVDV-1 and BVDV-2 was prevented in pregnant animals 5 months after vaccination. These findings suggest that the implementation of a two-step vaccination in the initial phase of control programmes in addition to test and removal of PI animals in areas with high cattle densities and endemic BVD is practical and efficacious.  相似文献   

Analysis of bulk milk samples using polymerase chain reaction: an additional tool for bovine viral diarrhea monitoring     

Bendfeldt S  Flebbe U  Fritzemeier J  Greiser-Wilke I  Grummer B  Haas L  Orban S  Peters E  Timm D  Moenning V 《DTW. Deutsche tier?rztliche Wochenschrift》2005,112(4):130-135

Programmes for the eradication and control of infections with bovine viral diarrhea virus (BVDV) concentrate on the identification and elimination of persistently infected (PI) animals. The identification of these animals is mainly based on the detection of viral antigen using ELISA techniques. Protocols detecting viral nucleic acid using RT-PCR have been described recently. Due to high costs the German model recommends screening of animals of 9 up to 36 months of age. Screening of bulk milk samples using RT-PCR technology would allow a system independent of age. The aim of the present study was to test whether bulk milk samples (1433 including max. 50 animals each) collected in four counties of Lower Saxony are suitable for a complementary identification of PI animals via RT-PCR. Thirty-one bulk milk samples derived from 27 dairy herds were BVDV positive, corresponding to 2.3 % of the herds analysed in this study. Two samples first scored doubtful. Follow up tests revealed lactating PI animals in most cases (18). In other cases the epidemiological status of the herd, i.e. high sero-prevalence and/or presence of PI animals among non-lactating cattle, suggested a transient infection detected in the first bulk milk sample. These results demonstrate that monitoring of lactating cattle of any age using RT-PCR is a very sensitive, economically effective additional method for the identification of PI animals.  相似文献   

Biotic Factors Affecting Expression of the 2,4-Diacetylphloroglucinol Biosynthesis Gene phlA in Pseudomonas fluorescens Biocontrol Strain CHA0 in the Rhizosphere     

Notz R  Maurhofer M  Schnider-Keel U  Duffy B  Haas D  Défago G 《Phytopathology》2001,91(9):873-881

ABSTRACT Production of the polyketide antimicrobial metabolite 2,4-diacetyl-phloroglucinol (DAPG) is a key factor in the biocontrol activity of Pseudomonas fluorescens CHA0. Strain CHA0 carrying a translational phlA'-'lacZ fusion was used to monitor expression of the phl biosynthetic genes in vitro and in the rhizosphere. Expression of the reporter gene accurately reflected actual production of DAPG in vitro and in planta as determined by direct extraction of the antimicrobial compound. In a gnotobiotic system containing a clay and sand-based artificial soil, reporter gene expression was significantly greater in the rhizospheres of two monocots (maize and wheat) compared with gene expression in the rhizospheres of two dicots (bean and cucumber). We observed this host genotype effect on bacterial gene expression also at the level of cultivars. Significant differences were found among six additional maize cultivars tested under gnotobiotic conditions. There was no difference between transgenic maize expressing the Bacillus thuringiensis insecticidal gene cry1Ab and the near-isogenic parent line. Plant age had a significant impact on gene expression. Using maize as a model, expression of the phlA'-'lacZ reporter gene peaked at 24 h after planting of pregerminated seedlings, and dropped to a fourth of that value within 48 h, remaining at that level throughout 22 days of plant growth. Root infection by Pythium ultimum stimulated bacterial gene expression on both cucumber and maize, and this was independent of differences in rhizosphere colonization on these host plants. To our knowledge, this is the first comprehensive evaluation of how biotic factors that commonly confront bacterial inoculants in agricultural systems (host genotype, host age, and pathogen infection) modulate the expression of key biocontrol genes for disease suppression.  相似文献   

Substrate-specific selective culture of cellulose splitting intestinal bacteria of small laboratory rodents     

N. -C. Juhr  A. Haas 《Veterinary research communications》1978,2(1):323-329

After undesired microbial infections have been successfully eliminated, as in specific-pathogen-free animals (SPF), research into the activity and effectiveness of the so-called normal flora becomes increasingly important when working with microbially defined laboratory animals. As a feature of pure microbial efficiency, cellulolytic activity is significant in the physiology of the small laboratory rodent.On the basis of existing knowledge, experiments were conducted on the substrate-specific, selective isolation of cellulolytic intestinal bacteria. The use of a system of enriched, continuous culture, for this purpose, is described. The isolation of cellulolytic intestinal bacteria, and testing for their activity, are illustrated by examples from the rat and guinea-pig.

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Kurzfassung Im Bemühen um das mikrobiell definierte Versuchstier kommt nach dem Ausschluß unerwünschter mikrobieller Einflüsse beim spezifisch pathogenfreien Tier (SPF) der Untersuchung des Einflusses der sogn. Normalflora und ihrer Leistung und Variabilität zunehmende Bedeutung zu.Cellulolytische Aktivität — als rein mikrobielle Leistung — ist für die kleinen Laboratoriumsnager ein Faktor von physiologischer Bedeutung. Auf der Basis vorliegender Kenntnisse wird über Untersuchungen zur substratspezifischen selektiven Isolierung cellulolytischer intestinaler Bakterien berichtet und der Einsatz des Systems der kontinuierlichen Kultur zur Anreicherung beschrieben.Am Beispiel von Ratte und Meerschweinchen wird die Isolierung und Aktivitäts-prüfung von Darmkeimen mit cellulolytischer Leistung dargestellt.

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