27 research outputs found

    Lawson criterion for ignition exceeded in an inertial fusion experiment

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    For more than half a century, researchers around the world have been engaged in attempts to achieve fusion ignition as a proof of principle of various fusion concepts. Following the Lawson criterion, an ignited plasma is one where the fusion heating power is high enough to overcome all the physical processes that cool the fusion plasma, creating a positive thermodynamic feedback loop with rapidly increasing temperature. In inertially confined fusion, ignition is a state where the fusion plasma can begin "burn propagation" into surrounding cold fuel, enabling the possibility of high energy gain. While "scientific breakeven" (i.e., unity target gain) has not yet been achieved (here target gain is 0.72, 1.37 MJ of fusion for 1.92 MJ of laser energy), this Letter reports the first controlled fusion experiment, using laser indirect drive, on the National Ignition Facility to produce capsule gain (here 5.8) and reach ignition by nine different formulations of the Lawson criterion

    Lawson Criterion for Ignition Exceeded in an Inertial Fusion Experiment

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    Inclusion body disease in two captive Australian pythons (Morelia spilota variegata and Morelia spilota spilota)

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    Two captive Australian pythons, one carpet and one diamond python, presented with signs of central nervous system dysfunction. The carpet python was agitated. Its head was tilting and it was incoordinated and had convulsions. It was treated with antibiotics and anthelmintics but was eventually euthanased after failing to respond to therapy. The diamond python had flaccid paralysis of the caudal half. It was not treated and became disoriented and died. Hepatocytes from both pythons contained irregular 2 to 10 m m eosinophilic intracytoplasmic inclusion bodies. The brain of the diamond python was not available for examination. Occasional neurones in the carpet python brain contained similar inclusion bodies and other changes suggestive of viral infection. The clinical signs and histopathological findings in both pythons were consistent with boid inclusion body disease

    Sunshine virus in Australian pythons

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    Sunshine virus is a recently discovered novel paramyxovirus that is associated with illness in snakes. It does not phylogenetically cluster within either of the two currently accepted paramyxoviral subfamilies. It is therefore only distantly related to the only other known genus of reptilian paramyxoviruses, Ferlavirus, which clusters within the Paramyxovirinae subfamily. Clinical and diagnostic aspects associated with Sunshine virus are as yet undescribed. The objective of this paper was to report the clinical presentation, virus isolation, PCR testing and pathology associated with Sunshine virus infection. Clinical records and samples from naturally occurring cases were obtained from two captive snake collections and the archives of a veterinary diagnostic laboratory. The clinical signs that are associated with Sunshine virus infection are localised to the neurorespiratory systems or are non-specific (e.g. lethargy, inappetence). Out of 15 snakes that were infected with Sunshine virus (detected in any organ by either virus isolation or PCR), the virus was isolated from four out of ten (4/10) sampled brains, 3/10 sampled lungs and 2/7 pooled samples of kidney and liver. In these same 15 snakes, PCR was able to successfully detect Sunshine virus in fresh-frozen brain (11/11), kidney (7/8), lung (8/11) and liver (5/8); and various formalin-fixed paraffin-embedded tissues (7/8). During a natural outbreak of Sunshine virus in a collection of 32 snakes, the virus could be detected in five out of 39 combined oral-cloacal swabs that were collected from 23 of these snakes over a 105 day period. All snakes that were infected with Sunshine virus were negative for reovirus and ferlavirus by PCR. Snakes infected with Sunshine virus reliably exhibited hindbrain white matter spongiosis and gliosis with extension to the surrounding grey matter and neuronal necrosis evident in severe cases. Five out of eight infected snakes also exhibited mild bronchointerstitial pneumonia. Infection with Sunshine virus should be considered by veterinarians investigating disease outbreaks in snakes, particularly those that are associated with neurorespiratory disease

    Hair lead levels to evaluate the subclinical impact of lead on growth in Sardinian children (Italy)

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    Objectives: The aim of this study was to determine if there are significant relationships between lead concentrations in children’s hair and height, sitting height, and estimated leg length. Methods: We analyzed three samples collected at different times: 1998, 2002, 2007. The total sample consisted of 825 children between 11 and 14 years of age living in different municipalities of Sardinia (Italy). Inductively coupled plasma atomic emission spectrometry (1998), inductively coupled plasma atomic absorption spectrometry (2002), and inductively coupled mass spectrometry (2007) were used to measure the lead concentration in hair (PbH). Some AAS measurements were also performed on the 1998 and 2007 samples to check the reliability of the data. Results: The mean PbH is much higher in 1998 (5.84 lg/g) than in 2002 (1.49 lg/g) and 2007 (0.78 lg/g). Multivariate regression analysis of the three samples, controlling for age and sex, indicates a subclinical impact of lead on growth that differs according to the mean lead concentration in the hair. In fact, for 1998, the relationships between all three anthropometric variables and logPbH are significantly negative. For 2002, there are significant negative associations between height and estimated leg length and logPbH but not between sitting height and logPbH. For 2007, there are not significant associations between logPbH and anthropometric variables. Conclusions: Our results support the use of hair lead levels as a biomarker to assess the impact of subclinical lead on the physical growth of children, especially when the study area presents medium and/or high levels of lead pollution
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