Experimental quantum speed-up in reinforcement learning agents.

As the field of artificial intelligence advances, the demand for algorithms that can learn quickly and efficiently increases. An important paradigm within artificial intelligence is reinforcement learning1, where decision-making entities called agents interact with environments and learn by updating their behaviour on the basis of the obtained feedback. The crucial question for practical applications is how fast agents learn2. Although various studies have made use of quantum mechanics to speed up the agent's decision-making process3,4, a reduction in learning time has not yet been demonstrated. Here we present a reinforcement learning experiment in which the learning process of an agent is sped up by using a quantum communication channel with the environment. We further show that combining this scenario with classical communication enables the evaluation of this improvement and allows optimal control of the learning progress. We implement this learning protocol on a compact and fully tunable integrated nanophotonic processor. The device interfaces with telecommunication-wavelength photons and features a fast active-feedback mechanism, demonstrating the agent's systematic quantum advantage in a setup that could readily be integrated within future large-scale quantum communication networks.

Glucose metabolism in patients with psoriasis.

BACKGROUND: Epidemiological studies strongly suggest that psoriasis predisposes to type 2 diabetes. Several theories have been proposed to explain how these disease entities might be pathophysiologically connected. OBJECTIVES: Our primary objective was to elucidate whether clinical data support the notion of common pathophysiological denominators in patients with psoriasis and type 2 diabetes, and thus to delineate the association between the two conditions that has arisen on the basis of epidemiological studies. METHODS: We reviewed clinical studies investigating parameters of glucose metabolism in patients with psoriasis. The PubMed and Embase databases were searched for studies investigating glucose metabolism in adult patients with psoriasis as a primary or secondary end point. Studies had to include a relevant control group. RESULTS: Twenty-six clinical studies reporting on insulin resistance, glucose tolerance or insulin secretion were eligible for review. The results were widely conflicting, with less than half of the studies showing results suggestive of defective glucose metabolism in patients with psoriasis. In general, the studies suffered from a lack of information regarding possible confounders and patient characteristics. Furthermore, the research methods varied, and in all but one study they might not have been appropriate to detect early and subtle defects in glucose metabolism. CONCLUSIONS: The available literature does not unequivocally support common pathophysiological denominators in psoriasis and type 2 diabetes. Well-designed clinical studies are needed to expose potential diabetogenic defects in the glucose metabolism in patients with psoriasis.

Relativistic quantum teleportation with superconducting circuits.

We study the effects of relativistic motion on quantum teleportation and propose a realizable experiment where our results can be tested. We compute bounds on the optimal fidelity of teleportation when one of the observers undergoes nonuniform motion for a finite time. The upper bound to the optimal fidelity is degraded due to the observer's motion. However, we discuss how this degradation can be corrected. These effects are observable for experimental parameters that are within reach of cutting-edge superconducting technology.

Transfer of maternal immunity to piglets is involved in early protection against Mycoplasma hyosynoviae infection.

Mycoplasma hyosynoviae causes arthritis in pigs older than 12 weeks. The role of colostrum in protection of piglets against M. hyosynoviae infection is not clear. Our objective was therefore to investigate whether transfer of maternal immunity to piglets was involved in early protection against the infection. Experimental infections were carried out in three groups of weaners receiving different levels of M. hyosynoviae-specific colostrum components; Group NC derived from Mycoplasma free sows and possessed no specific immunity to M. hyosynoviae. Group CAb pigs, siblings of the NC group, received colostrum with M. hyosynoviae-specific antibodies immediately after birth. Group CCE pigs were born and raised by infected sows and presumably had the full set of colostrally transferred factors, including specific antibodies. When 4½ weeks old, all pigs were inoculated intranasally with M. hyosynoviae. The course of infection was measured through clinical observations of lameness, cultivation of M. hyosynoviae from tonsils, blood and synovial fluid and observation for gross pathological lesions in selected joints. Specific immune status in the pigs was evaluated through detection of antibodies by immunoblotting and measurement of M. hyosynoviae-specific T-cell proliferation. The latter analysis may possibly indicate that M. hyosynoviae infection induces a T-cell response. The CCE piglets were significantly protected against development of lameness and pathology, as well as infection with M. hyosynoviae in tonsils, blood and joints, when compared to the two other groups. Raising the CCE pigs in an infected environment until weaning, with carrier sows as mothers, apparently made them resistant to M. hyosynoviae-arthritis when challenge-infected at 4½ weeks of age. More pigs in group NC had M. hyosynoviae related pathological lesions than in group CAb, a difference that was significant for cubital joints when analysed on joint type level. This finding indicates a partially protective effect of passively transferred M. hyosynoviae-specific colostral antibodies upon development of M. hyosynoviae related pathology. Thus, the level of passive immunity transferred from sow to piglet seems to provide, at least partial, protection against development of arthritis. It cannot be ruled out that the CCE pigs, by growing up in an infected environment, have had the chance to establish an active anti-M. hyosynoviae immune response that complements the maternally transferred immune factors. Evident from this study is that the general absence of M. hyosynoviae arthritis in piglets can be ascribed mainly to their immunological status.

In situ hybridisation for identification and differentiation of Mycoplasma hyopneumoniae, Mycoplasma hyosynoviae and Mycoplasma hyorhinis in formalin-fixed porcine tissue sections.

Oligonucleotide probes targeting 16S ribosomal RNA were designed for species-specific identification of the porcine mycoplasmas Mycoplasma hyopneumoniae, Mycoplasma hyorhinis and Mycoplasma hyosynoviae using a fluorescent in situ hybridisation assay. The specificity of the probes was evaluated using pure cultures as well as porcine tissue sections with artificial presence of mycoplasma, and the probes were found specific for the target organisms. The assay was applied on sections of 28 tissue samples from pigs infected with one or more of the three Mycoplasma species as determined by cultivation. M. hyopneumoniae and M. hyorhinis were identified in accordance with cultivation in lung sections from nine pigs affected by catarrhal to purulent bronchopneumonia. Likewise, in eight cases of fibrinous pericarditis, M. hyopneumoniae, M. hyorhinis and M. hyosynoviae were the infectious agents according to cultivation and were correctly identified by in situ hybridisation. Out of 11 joints cultivation positive for M. hyosynoviae, the probe was only able to identify M. hyosynoviae in eight cases probably due to a low number of microorganisms in the tissue sections. The in situ hybridisation assay is well suited for use in diagnostic and experimental work as well as a tool for pathogenesis studies.

Genetic variations among Mycoplasma bovis strains isolated from Danish cattle.

The genetic heterogeneity of Mycoplasma bovis strains isolated in Denmark over a 17-year period was investigated. Forty-two field strains isolated from different geographic locations and specimens, including strains from 21 herds involved in two outbreaks of M. bovis-induced mastitis, and the type strain of M. bovis (PG45(T)) were assayed for variations in the BglII and MfeI restriction sites in the chromosomal DNA by using the amplified fragment length polymorphism (AFLP) fingerprinting technique. The obtained genomic fingerprints consisted of 62-68 AFLP fragments in the size range of 50-500 bp. Among the analyzed strains, 18 different AFLP profiles were detected. The similarity between individual fingerprints, calculated by Dice similarity coefficient, ranged from 0.9 to 1.0. Twenty-five strains, including 23 which were isolated during two outbreaks of M. bovis-induced mastitis which occurred 2 years apart, showed indistinguishable AFLP patterns. More genetic diversity was observed among the recent strains. The similarity of the genotypes of the field strains to that of the M. bovis type strain (PG45(T)) was 97.7%. The results of this study have demonstrated a remarkable genomic homogeneity of Danish strains of M. bovis that were probably epidemiologically related and which have remained stable for a considerable length of time. Furthermore, this study has demonstrated that AFLP can be used for genomic fingerprinting and discrimination of M. bovis strains.

Antimicrobial susceptibility testing of Mycoplasma hyosynoviae isolated from pigs during 1968 to 1971 and during 1995 and 1996.

This study was conducted to compare the Minimal Inhibitory Concentrations (MICs) for enrofloxacin, lincomycin, tetracycline, tiamulin and tylosin, of Mycoplasma hyosynoviae, isolated from pigs at notably different intervals (1968-71 and 1995-96). Each group comprised 21 low passage isolates and a Danish reference strain (M60) and the type strain (S16). MICs were determined in liquid medium with both initial and final readings. Enrofloxacin, lincomycin, tetracycline and tiamulin were active against all isolates, and tiamulin showed the highest activity. For tylosin all the isolates from 1968-71 were highly susceptible, whereas the isolates from 1995-96 could be divided into a highly susceptible (nine isolates) and relatively resistant (12 isolates) group. This difference between old and new strains was statistically significant (p = 0.0000415). The remaining agents, enrofloxacin, lincomycin, tiamulin and tetracycline, showed an unaltered good activity against M. hyosynoviae. The resistance to tylosin seems now to occur so often that this antibiotic cannot be recommended for therapeutic use any more. The most probable explanation for the emergence of resistance is the intensive use of tylosin during many years for therapy and growth promotion.

Aerosol challenge of calves with Haemophilus somnus and Mycoplasma dispar.

The aim of the study was to examine the ability of Haemophilus somnus and Mycoplasma dispar to induce pneumonia in healthy calves under conditions closely resembling the supposed natural way of infection, viz. by inhalation of aerosol droplets containing the microorganisms. The infections were investigated by recording clinical data, cytokine expression of peripheral blood cells and pathology. Twelve calves were included in the study: Three animals were exposed to H. somnus only, and two to M. dispar only, whereas five were challenged to M. dispar followed by exposure to H. somnus 11-14 days later. Also, one calf was exposed to M. dispar followed by exposure to a sterile saline solution 11 days later, and one calf was only exposed to a sterile saline solution. Just one animal, only challenged with H. somnus, developed a focal necrotizing pneumonia, from which H. somnus was isolated. Thus, the ability of H. somnus and M. dispar to act as primary pathogens under these conditions were minimal and inconsistent.However, a transient rise in body temperature, a marked granulocytosis and increased levels of interleukin-8 in peripheral blood after inoculation with H. somnus indicated a clear systemic response, probably as a consequence of the natural non-specific local and systemic defence mechanisms acting in healthy calves.

A monoclonal blocking ELISA detecting serum antibodies to Mycoplasma hyopneumoniae.

A monoclonal blocking enzyme-linked immunosorbent assay (ELISA) for detection of antibodies to Mycoplasma hyopneumoniae in porcine serum has been developed. The monoclonal antibody (mAb) reacts with an M. hyopneumoniae specific epitope on a molecule of approximately 74 kDa. Only sera from M. hyopneumoniae infected pigs were able to block the binding of the mAb although antibodies from M. flocculare infected pigs also recognized a 74 kDa molecule. Sera from experimentally infected pigs as well as field samples were compared by the ELISA and by an indirect hemagglutination assay (IHA). In experimental pigs, the earliest detectable antibody response was found to be almost identical for both assays, but for some of the pigs the time of detection was significantly earlier by blocking ELISA than by IHA. In naturally infected herds more samples were found to be positive by ELISA than by IHA. Furthermore, the results indicate that sera from naturally M. flocculare infected pigs may give rise to cross-reactions in the IHA. The blocking ELISA appears to be a valuable and reproducible tool in the surveillance and serodiagnosis of M. hyopneumoniae infections in pigs.

Molecular analysis of field strains of Mycoplasma capricolum subspecies capripneumoniae and Mycoplasma mycoides subspecies mycoides, small colony type isolated from goats in Tanzania.

A molecular analysis of strains of Mycoplasma capricolum subsp. capripneumoniae (M. capripneumoniae) and Mycoplasma mycoides subsp. mycoides, small colony type (M. mycoides SC) isolated from goats was performed using the amplified fragment length polymorphism (AFLP) and pulsed-field gel electrophoresis (PFGE) fingerprinting techniques. Among the 11 field strains of M. capripneumoniae from Tanzanian goats, two AFLP patterns were demonstrated, with 10 of the strains showing indistinguishable patterns. Five Kenyan strains of M. capripneumoniae produced three AFLP patterns, with two of them being indistinguishable from the 10 identical Tanzanian and one Ugandan strain (M74/93) isolated from sheep. The AFLP pattern of the type strain (F38(T)) was identical to two Kenyan strains (Baringo and G183/82). On PFGE analysis, all the examined M. capripneumoniae strains exhibited identical PFGE profiles.Five field strains of M. mycoides SC isolated from goats displayed identical AFLP patterns except for one strain which differed from others at only one position. The AFLP pattern of the type strain of M. mycoides SC (PG1(T)) was different from the field strains. The five field strains of M. mycoides SC produced identical PFGE profiles, which were, however, different from the type strain. The AFLP and PFGE profiles of M. mycoides SC strains from goats were identical to those of six strains isolated from cattle affected with contagious bovine pleuropneumonia (CBPP) in the same areas. The results of this study suggest a close epidemiological linkage between strains of M. capripneumoniae and between M. mycoides SC type, respectively, isolated from goats in Tanzania.

Mycoplasma hyopneumoniae infection in pigs: duration of the disease and evaluation of four diagnostic assays.

200 SPF pigs were infected by aerosol with Mycoplasma hyopneumoniae and the development of clinical signs, serological and pathological reactions were studied. Mean time to onset of coughing was 13 days. A mean delay of 9 days was observed from onset of coughing until seroconversion against M. hyopneumoniae as measured by ELISA. At an individual level, the sensitivity for this ELISA was estimated to 98-100% and the specificity to 93-100%. Pasteurella multocida was isolated from the majority of the lungs 4 weeks post inoculation with M. hyopneumoniae and the lung lesions in pigs were significantly larger when P. multocida was present as compared to pigs with M. hyopneumoniae alone. An evaluation of cultivation, immunofluorescence, ELISA and polymerase chain reaction for demonstration of M. hyopneumoniae in lungs showed that all four methods have a high sensitivity in the acute stages of pneumonia. In the later stages the sensitivity of cultivation was superior to the other methods. No differences in specificity were observed between the methods. The antigen-ELISA OD values and the immunofluorescence scores revealed a strong positive correlation. Nasal swabs were additionally used for demonstration of M. hyopneumoniae and the polymerase chain reaction was found superior to the other methods.

Morphological and ultrastructural studies of Mycoplasma flocculare and Mycoplasma hyopneumoniae in vitro.

Cells of Mycoplasma flocculare were found to vary in size and shape, especially in the later phases of growth, whereas those of Mycoplasma hyopneumoniae were fairly uniform irrespective of growth phases. Filamentous cells were present in cultures of M flocculare in the stationary and declining phases, but were never found in cultures of M hyopneumoniae. The filamentous and bizarre forms observed when mycoplasmas were suspended in phosphotungstic acid probably result from the action of the hypotonic solution. The surface of all cells was covered by a fuzzy coat consisting of fine hairs or bristles. An electron-lucent region was usually seen in cells negatively stained after centrifugation, but was only occasionally seen in cells negatively stained directly from the medium. Intracytoplasmic membranes were present in sectioned cells. No attachment organelle was found in cells of either species.

Swine mycoplasmoses.

Mycoplasma hyopneumoniae is the primary agent of enzootic pneumonia in pigs. The lung lesions, generally observed in young pigs, are characterised by a hyperplasia of the epithelial cells and an increased perivascular and peribronchiolar accumulation of mononuclear cells. Following M. hyopneumoniae infection, immune reactions are observed and resistance is induced in pigs. Laboratory diagnosis is generally performed by an immunofluorescent test and by enzyme-linked immunosorbent assay. Antibiotics are useful but the development of resistance has been described. Vaccination seems to be an effective method of controlling the disease. M. hyorhinis, generally transmitted by sows to piglets through nasal secretions, exists in a high percentage in the respiratory tract of healthy pigs. But some strains can induce serofibrinous to fibrinopurulent polyserositis and arthritis. M. hyorhinis is isolated from acute and subacute phase lesions and serum antibodies are detectable. M. hyosynoviae has a special affinity for joint tissue and may cause arthritic disease, leading to economic losses. This mycoplasma is generally located in the tonsils. Piglets are infected by sows after four to six weeks of life. Evidence of disease occurs in animals of between 30 to 40 kg and 100 kg, and bursae and joints are affected. A non-suppurative viscous fluid of a serofibrinous/serosanguineous nature is reported. In chronic cases, the synovial membrane is affected. M. hyosynoviae is isolated from the joints and pharyngeal/tonsillar samples and can induce antibodies in blood and joint fluid. Predisposing factors play an important role. M. flocculare is widely distributed in swine, in normal and pneumonic lungs and in nasal cavities, but no pathogenic capability has been described. There is great interest in this mycoplasma because of the great similarity to M. hyopneumoniae.

Isolation of Mycoplasma flocculare from swine in the United States.

During 1977 to 1980, Mycoplasma flocculare was isolated from the lungs of 7 swine in the United States. Two of the swine were from a single Alabama herd, 1 was from Minnesota, 2 were from different Illinois herds, and 2 were from different Indiana herds. Three of the swine were from specific-pathogen-free herds and 4 were from conventional herds. The lungs from the 7 swine had gross lesions typical of mycoplasmal pneumonia. Two lungs yielded a mixture of M flocculare and M hyopneumoniae; the remaining 5 yielded M flocculare alone.

Mycoplasma canis and urogenital disease in dogs in Norway.

Mycoplasmas identified as Mycoplasma canis were isolated from nine dogs with clinical signs of urogenital disease in Norway over a period of 20 months. Some of the dogs had been treated unsuccessfully with antibiotics, and three were euthanased as a result of severe persistent disease. Seven of the dogs had a urinary tract infection, one had chronic purulent epididymitis and one had chronic prostatitis. Overt haematuria was frequently observed among the dogs with cystitis. M canis was isolated in pure culture from seven of the dogs and in mixed culture from the other two. In three cases the mycoplasma was cultivated only from urinary sediment, and it was typically obtained in smaller numbers than would be considered indicative of a urinary tract infection. In contrast with most mycoplasmas, the M canis isolated from all the dogs grew on ordinary blood agar plates used for routine bacteriological cultivation. Specific mycoplasma media were not used and the presence of other Mycoplasma or Ureaplasma species cannot be excluded.

Sensitivity of certain porcine and bovine mycoplasmas to antimicrobial agents in a liquid medium test compared to a disc assay.

The sensitivity of some porcine and bovine mycoplasmas to potent antimicrobial agents was examined. Minimal inhibitory concentration (MIC) values were estimated for M. hyosynoviae, M. hyopneumoniae, M. dispar and M. bovis against enrofloxacin, lincomycin, tetracycline, tiamulin and tylosin, in a liquid medium test and in a disc assay. All 6 examined strains of each species and the respective type strains were significantly inhibited. The greatest sensitivity was noted for tiamulin against strains of M. hyosynoviae with a final MIC50 broth value of 0.025 micrograms ml-1 and disc value of 0.03 microgram per disc. Enrofloxacin was found very potent against M. hyopneumoniae with a final MIC50 of 0.025 microgram ml-1 and 0.1 microgram per disc, and for M. dispar with 0.05 microgram ml-1 and 0.03 microgram per disc. Most disc assay estimates in micrograms per disc were similar to or moderately greater than corresponding final broth figures in microgram ml-1. It may be possible to convert observed disc assay values into representative final broth MIC values for use in the clinic.

Mycoplasma hyorhinis in the etiology of serositis among piglets.

In a study on the involvement of Mycoplasma hyorhinis in serositis of piglets, 26 routine diagnostic animals, 3-7 weeks old, with distinct serofibrinous lesions in the pericardial, pleural and peritoneal cavities were examined. M. hyorhinis was isolated in 9 cases, non-haemolytic Escherichia coli in another 9 cases and in 4 cases both species were found. Neither of the microorganisms were found in the remaining 4 cases. The presence of M. hyorhinis in the serous cavities in the absence of non-haemolytic E. coli was always accompanied by a diagnosis of other disease conditions, mainly of the respiratory tract. In the cases infected with non-haemolytic E. coli complicating problems were absent. The pathogenicity of M. hyorhinis was further studied by inoculation of 2 young pigs in which the typical serofibrinous lesions of the serous cavities were produced. It therefore appears that M. hyorhinis can be regarded as a cause of polyserositis in piglets; under field conditions, however, the synergistic presence of other debilitating syndromes appears necessary for its haematogenous spread from the respiratory tract to the serous cavities.

Increasing prevalence of Mycoplasma bovis in Danish cattle.

A study on the prevalence of mycoplasmas in pneumonic bovine lungs was performed on material submitted for diagnostic purposes at the Danish Veterinary Laboratory, Copenhagen. Among the 50 examined cases 43 (86.0%) were found to be infected with mycoplasmas. The predominant mycoplasmas were Ureaplasma spp. (72.0%), M. dispar (48.0%) and M. bovis (24.0%). Other mycoplasmas were M. bovirhinis (20.0%) and M. bovigenitalium (6.0%). Among the infected lungs multiple species infections were predominant (76.7%) over single species infections (23.3%) with M. dispar-Ureaplasma (25.6%), M. bovis-Ureaplasma (18.6%) and M. dispar-M. bovirhinis-Ureaplasma (11.6%) infections being the most frequently encountered combinations. There appears to be an increasing prevalence of M. bovis (24.0%) as compared to earlier reports (0.6-2.0%), thus calling for special attention upon this mycoplasma. Pulsed field gel electrophoresis (PFGE) analysis of 11 field isolates of M. bovis from 9 different farms revealed different profiles except for 2 isolates which were recovered from the same farm. Because mycoplasmas belonging to the 'M. mycoides cluster' were not encountered during this study; it appears that the Danish cattle population is still free from this group of mycoplasma in spite of their presence in some other European countries.

Mycoplasma hyosynoviae isolation from the upper respiratory tract and tonsils of pigs.

The occurrence of Mycoplasma hyosynoviae at different locations of the upper respiratory tract and tonsils of pigs was investigated in herds with problems of arthritis apparently caused by this microorganism. The isolation of M. hyosynoviae was facilitated by the use of a medium selectively suppressing the growth of Mycoplasma hyorhinis. M. hyosynoviae was cultured from 106 of 178 tonsils of slaughterhouse pigs from 8 herds but could not be isolated from the mucosa of the nasal cavity or the oral-pharyngeal area of 100 living, 10-20 weeks old pigs in 5 of the herds. The value of the selective principles in the medium appears from the circumstance that 86 of the 106 isolates were obtained despite the presence of M. hyorhinis. It is concluded that the tonsil is a reservoir for M. hyosynoviae and is probably the location of choice for an easy demonstration of the presence of this mycoplasma in a pig herd.

Mycoplasma hyosynoviae in joints with arthritis in abattoir baconers.

The occurrence of Mycoplasma hyosynoviae in synovial fluid of baconers with chronic arthritis was studied at an abattoir. Cultural examination of synovial fluid samples from diseased tarsal joints of 50 animals from 42 herds yielded M. hyosynoviae in 10 cases from 8 herds. Streptococci were found in 6 cases from 6 other herds. M. hyosynoviae antigen was found in 1 of 47 of the samples, and antibody to the mycoplasma was found in 14 of 40 of the samples by ELISA test. The presence of M. hyosynoviae in a joint was usually accompanied by the corresponding antibody. In joints with streptococcal infection antibody to M. hyosynoviae could not be found.