939 research outputs found
Nuclear data uncertainty quantification on PWR spent nuclear fuel as a function of burnup
Nuclear data uncertainty analysis on the spent nuclear fuel inventory was performed on the Takahama-3 NT3G23 assembly, where the sample SF95-4 was irradiated up to a burnup of approximately 36 GWd/ t according to the SFCOMPO benchmark. The cross-section covariance matrices stored in the ENDF/B-VIII.0, JEFF-3.3 and JENDL-4.0u evaluated nuclear data libraries were propagated with the stochastic sampling algorithms implemented in the SANDY code. A comparison of the concentration uncertainty differences obtained using data from the three libraries is reported. Similarities were found with the fuel composition uncertainty results obtained for the Calvert Cliffs MKP109 sample P SFCOMPO benchmark. Such a similarity was also found when comparing concentration uncertainties along the sample irradiation. Therefore, the main contributors to the concentration uncertainty of a number of nuclides were identified at different burnup levels in the two samples. To complement the similarity analysis, a correlation study of the concentration distributions predicted by the two models was performed. The reported results hint a dominance of the common uncertainty propagation mechanisms over the model differences in the determination of concentration uncertainty
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Grow Smart and Die Young: Why Did Cephalopods Evolve Intelligence?
Intelligence in large-brained vertebrates might have evolved through independent, yet similar processes based on comparable socioecological pressures and slow life histories. This convergent evolutionary route, however, cannot explain why cephalopods developed large brains and flexible behavioural repertoires: cephalopods have fast life histories and live in simple social environments. Here, we suggest that the loss of the external shell in cephalopods (i) caused a dramatic increase in predatory pressure, which in turn prevented the emergence of slow life histories, and (ii) allowed the exploitation of novel challenging niches, thus favouring the emergence of intelligence. By highlighting convergent and divergent aspects between cephalopods and large-brained vertebrates we illustrate how the evolution of intelligence might not be constrained to a single evolutionary route.M.B., N.S.C. were funded by the European Research Council under the European Union’s Seventh Framework Programme (FP7/2007-2013)/ERC Grant Agreement No. 3399933, awarded to N.S.C. A.S. was supported by an Endeavour Research Fellowship, funded by the Australian Government
Pro‑differentiating compounds for human intervertebral disc cells are present in Violina pumpkin leaf extracts
The intervertebral disc degeneration (IDD) is closely associated with inflammation, oxidative stress and loss of the discogenic phenotype which current therapies are unable to reverse. Here, the effects of acetone extract from Violina pumpkin (Cucurbita moschata) leaves on degenerated intervertebral disc (IVD) cells was investigated. IVD cells were isolated from degenerated disc tissue of patients undergoing spinal surgery, and exposed to acetone extract and three major thin layer chromatography subfractions. We found that the cells benefit from exposure in particular to subfraction 7 consisting almost entirely of p-Coumaric acid. Subfraction 7-treated cells showed a significant increase of discogenic transcription factors (SOX9, TRPS1), extracellular matrix components (aggrecan, collagen type II), cellular homeostasis and stress response regulators (FOXO3a, Nrf2, SOD2, SIRT1). Migratory ability and the expression of OCT4, two important markers related to the presence and activity of stem cells also increased. Moreover, subfraction 7 counteractes H2O2-triggered cell damage preventing in particular the increase of the pro-inflammatory and antichondrogenic microRNA, miR-221. This strengthens the hypothesis that adequate stimuli can support resident cells to repopulate the degenerate IVD and restart the anabolic machinery. Taken together, the data we obtained contribute to the discovery of molecules potentially effective in slowing the progression of IDD, a disease for which there is currently no effective treatment. Moreover, the enhancement of a part of plant, the pumpkin leaves, considered a waste product in the Western world, demonstrating that it contains substances with potential beneficial effects on human health
Multi-component measurements of the Jefferson Lab energy recovery linac electron beam using optical transition and diffraction radiation
High brightness electron accelerators, such as energy recovery linacs (ERL),
often have complex particle distributions that can create difficulties in beam
transport as well as matching to devices such as wigglers used to generate
radiation from the beam. Optical transition radiation (OTR), OTR interferometry
(OTRI) and optical diffraction-transition radiation interferometry (ODTRI) have
proven to be effective tools for diagnosing both the spatial and angular
distributions of charged particle beams. OTRI and ODTRI have been used to
measure rms divergences and optical transverse phase space mapping has been
demonstrated using OTRI. In this work we present the results of diagnostic
experiments using OTR and ODR conducted at the Jefferson Laboratory 115 MeV ERL
which show the presence of two separate components within the spatial and
angular distributions of the beam. By assuming a correlation between the
spatial and angular features we estimate an rms emittance value for each of the
two components.Comment: 25 pages, 10 figures; accepted for publication in PRSTAB; minor
formatting errors correcte
Abdominal pain as first manifestation of lyme neuroborreliosis in children, case report and review of literature
Background: Lyme neuroborreliosis can cause a variety of neurological manifestations. European children usually present facial nerve palsy, other cranial nerve palsies and aseptic meningitis. Case presentation: We hereby report a case of Lyme neuroborreliosis in a 9-year-old boy with abdominal pain as first symptom and subsequent onset of attention deficit and ataxia. Diagnosis was made by detection of specific antibody in both serum and cerebrospinal fluid with neuro-radiological images suggestive for this infectious disease. A 12-months follow-up was performed during which no relevant neurological sequelae were revealed. Conclusion: This case report shows that abdominal radiculitis, although extremely rare, could be the first manifestation of early Lyme neuroborreliosis in pediatric patients. Pediatricians must consider Lyme disease in the differential diagnosis of abdominal pain of unknown origin in children, especially in countries where the infection is endemic
Changes in union membership over time : a panel analysis for West Germany
Despite the apparent stability of the wage bargaining institutions in West Germany, aggregate union membership has been declining dramatically since the early 90's. However, aggregate gross membership numbers do not distinguish by employment status and it is impossible to disaggregate these sufficiently. This paper uses four waves of the German Socioeconomic Panel in 1985, 1989, 1993, and 1998 to perform a panel analysis of net union membership among employees. We estimate a correlated random effects probit model suggested in Chamberlain (1984) to take proper account of individual specfic effects. Our results suggest that at the individual level the propensity to be a union member has not changed considerably over time. Thus, the aggregate decline in membership is due to composition effects. We also use the estimates to predict net union density at the industry level based on the IAB employment subsample for the time period 1985 to 1997. JEL - Klassifikation: J
Distribution in the brain and possible neuroprotective effects of intranasally delivered multi-walled carbon nanotubes
Carbon nanotubes (CNTs) are currently under active investigation for their use in several biomedical applications, especially in neurological diseases and nervous system injury due to their electrochemical properties. Nowadays, no CNT-based therapeutic products for internal use appear to be close to the market, due to the still limited knowledge on their fate after delivery to living organisms and, in particular, on their toxicological profile. The purpose of the present work was to address the distribution in the brain parenchyma of two intranasally delivered MWCNTs (MWCNTs 1 and a-MWCNTs 2), different from each other, the first being non electroconductive while the second results in being electroconductive. After intranasal delivery, the presence of CNTs was investigated in several brain areas, discriminating the specific cell types involved in the CNT uptake. We also aimed to verify the neuroprotective potential of the two types of CNTs, delivering them in rats affected by early diabetic encephalopathy and analysing the modulation of nerve growth factor metabolism and the effects of CNTs on the neuronal and glial phenotypes. Our findings showed that both CNT types, when intranasally delivered, reached numerous brain areas and, in particular, the limbic area that plays a crucial role in the development and progression of major neurodegenerative diseases. Furthermore, we demonstrated that electroconductive MWCNTs were able to exert neuroprotective effects through the modulation of a key neurotrophic factor and probably the improvement of neurodegeneration-related gliosis
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