1,189 research outputs found

    Marginally Deformed Starobinsky Gravity

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    We show that quantum-induced marginal deformations of the Starobinsky gravitational action of the form R2(1α)R^{2(1 -\alpha)}, with RR the Ricci scalar and α\alpha a positive parameter, smaller than one half, can account for the recent experimental observations by BICEP2 of primordial tensor modes. We also suggest natural microscopic (non) gravitational sources of these corrections and demonstrate that they lead generally to a nonzero and positive α\alpha. Furthermore we argue, that within this framework, the tensor modes probe theories of grand unification with a large scalar field content.Comment: 5 pages, 1 figure, 2 column

    En fremgangsmåde ved bestemmelse af normalområde for haematologiske og klinisk kemiske parametre

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    The reproducibility within the laboratory of findings in a three month toxicity study in the rat

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    A three month rat toxicity study was conducted twice with the same compound in the same laboratory. The studies were conducted according to internationally recognized guidelines for subchronic toxicity studies and followed essentially identical protocols (a control group and three dose groups, 10 rats/sex/ group). The compound was administered subcutaneously once daily for three months. Body weight and food and water intake were measured once weekly. Blood samples for hematology and blood chemistry were taken during the week before termination of dosing. Body weight gain and food and water intake were increased in both studies. For great many hematological and blood chemical parameters there was a dosedependent statistically significant increase or decrease in one or both sexes. Some changes attained only the level of significance in one study whereas there was a tendency of a similar change in the other study. Only a few deviations (no or opposit change in one study) were seen between the two studies. Altogether there seemed to be a good correspondance between the findings in the two studies and the variations seen would probably not influence the safety evaluation made from any of the studies

    Effects of pre- or postoperative morphine and of preoperative ketamine in experimental surgery in rats, evaluated by pain scoring and c-fos expression

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    Since Wall (1988) hypothesised a beneficial post surgical effect of preoperative analgesic treatment (so-called pre-emptive analgesic treatment) as a supplement to postoperative analgesic treatment, the concept has been subject to many scientific debates. According to the hypothesis, applying analgesics before the nociceptive stimulus is beneficial due to reduced wind-up and reduced central sensitisation resulting in diminished risk of postoperative hyperalgesia and allodynia (Woolf and Chong, 1993). The scientific literature provides conflicting evidence for this theory. Beneficial effect of preemptive analgesic treatment has been reported after pre-emptive treatment with local analgesics, opioids and NSAID´s compared with placebo (Woolf and Chong, 1993). Some clinical settings have showed beneficial analgesic effect of preemptive analgesia, when the same pre-emptive and postoperative treatments with lidocaine (Ejlersen et al., 1992; Doyle and Bowler, 1998) or opioids (Katz et al., 1992) were compared. However, Dahl et al. (1992) and Elhakim et al. (1995) did not obtained supportive results in their clinical studies.In the majority of studies using animal models addressing this concept, the nociceptive stimulus has been obtained by injection of irritating chemicals, in particular formalin. When somatic tissue is damaged or irritated, nociceptive receptors are activated by peripheral release of extracellular inflammatory mediators. The activated receptors lead the signal to the synapses in the dorsal horn of the spinal cord as a 2-phased signal. In the acute first phase, nociceptive stimuli are mediated centrally through Aä fibres fibres. During the slower and long-lasting second phase, the nociceptive stimuli are mediated mainly through C-fibres (Cross et al., 1994). The release of extracellular inflammatory mediators increases the peripheral excitability, which leads to hyperalgesia (Woolf, 1995). Repetitive peripheral nociceptive impulses mediated through C-fibres result in an increased central excitability of dorsal appears to be in part mediated through N-methylhorn neurones. This state is called wind-up and appears to be in part mediated through N-methyl- D-aspartate (NMDA) receptors on dorsal horn secondary nociceptive neurones. Transmission of multiple slow stimuli leads to release of glutamate, which removes the Mg++-block in the NMDA receptor and allows substantial Ca++-inflow (Urban et al., 1994). NMDA receptor antagonists bind to the same site as Mg++ and prevents Ca++- inflow (Hirota and Lambert, 1996; Kress, 1997). NMDA-receptor antagonists can prevent wind-up but not the initial responses of the neurones, whereas the reverse is true for opioids (Chapman and Dickenson, 1992). NMDA-antagonists have no effect on pain of the acute first phase, but may act synergistic to the analgesic effect of opioids (Chapman and Dickenson, 1992; Honoré et al., 1996). Only few studies deal with a postoperative experimental model in animals and those available are conflicting. Brennan et al. (1996) developed an elegant postoperative model in rats with surgical intervention on the plantar surface of the hind foot. In this study a relationship was found between behavioural pain observation scores and mechanical hyperalgesia. Ovariohysterectomized rats have also been used as animal models of postoperative pain (Lascelles et al. 1995). A commonly used method of determining the nociceptive activity caused by a peripheral stimulus is to identify and quantify the nuclear protein Fos expressed in secondary nociceptive neurones in the spinal cord. c-fos is an immediate early gene (IEG), that encodes for Fos. IEG’s are rapidly and transiently induced in neuronal cells within minutes of extracellular stimulation (Sheng and Greenberg, 1990). The c-fos mRNA accumulates, and reaches its peak after 30 to 40 minutes. The Fos level peaks approximately two hours after induction of c-fos (Harris, 1998). Since Hunt (1987) reported, that peripheral inflammation induced c-fos in neurones in the dorsal horn of the spinal cord, many studies have shown the relationship between nociception and cfos expression.The aim of the present investigation was to study the effect of pre-emptive versus postoperative opioid analgesic treatment by use of the surgical model of Brennan et al. (1996) and combine the pre-emptive and postoperative opioid treatment with pre-emptive ketamine. The effects were quantified by stereological estimation of the number of dorsal horn neurones expressing c-fos and pain scoring from the operated hind foot

    Prediction of N2O Solubility in Alkanolamine Solutions from the Excess Volume Property

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    AbstractThe CO2 solubility is very important property when establishing thermodynamic models for the VLE. In order to obtain the CO2 solubility the normal procedure is to use the N2O analogy as the CO2 solubility cannot be directly measured. This calls for a rather extensive experimental program. In this work a simple and less laborious model was developed based on the excess molar volumes to estimate the excess Henry's constant. This method only requires density data and the N2O solubility into pure solvents (Water/Alkanolamine). The model works well to represent experimental data for different temperatures and concentrations

    Fulfilment of grid code obligations by large offshore wind farms clusters connected via HVDC corridors

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    The foreseen high penetration levels of wind power will force the systems operators to apply restrictive constraints on wind power plants. The ability of offshore wind clusters, which are connected via HVDC, to fulfill the grid codes, especially those related to voltage stability is investigated. This came in the frame of a project to develop an integrated and practical tool to design offshore wind clusters (EERA-DTOC). The applied case studies examine the system stability during and after severe disturbances, and the compliance with the grid codes. Additionally, this paper explains the applied procedure to utilize the outcomes of Net-OP tool, which proposes an optimized topology to connect the wind power clusters to the interconnected power systems. The integrated simulation environment, namely, PSS/E, is used to implement a highly detailed and dynamic model based on the recommendations of Net-OP tool. The results confirm that wind farm clusters respond to faults and disturbances as desired by the grid codes

    Haematology in mice after weekly blood sampling for 7 weeks

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    Haematologic and Clinical Chemical values in 3 and 6 months old Göttingen minipigs

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    Blood samples were collected from sixty healthy Göttingen minipigs. fifteen males and fifteen females at the age of three months and fifteen males and fifteen females at the age of six months. The samples were taken at the breeder’s facilities. The samples were analysed for nineteen haematological and twenty~six clinical chemical parameters. Means, standard deviations and lowest and highest values are presented. In general the parameters were comparable with those reponed for other breeds of miniature and domestic swine. The white blood cell count, the percentages of neutrophils and monocytes and serum globulin levels were lower in these microbiologically defined minipigs compared with conventionally rearedpigs and minipigs. Three litter mates had a complex of abnormally high serum creatine kinase, lactate dehydrogenase, uspartate aminotransterase and alanine aminotmnsferase levels

    Isgur - Wise Functions for Confined Light Quarks in a Colour Electric Potential

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    We explore the influence on the Isgur-Wise function of the colour electric potential between heavy and light quarks in mesons. It is shown that in bag models, its inclusion tends to restore light quark flavour symmetry relative to the MIT bag predictions, and that relative to this model it flattens the Isgur-Wise function. Results compare very well with observations.Comment: 9 pages, 1 figure (available upon request), Latex, TPJU - 4/9
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