| 1. |
- Martin, P., et al.
(författare)
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Overview of RFX-mod results
- 2009
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 49:10, s. 104019-
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Tidskriftsartikel (refereegranskat)abstract
- With the exploration of the MA plasma current regime in up to 0.5 s long discharges, RFX-mod has opened new and very promising perspectives for the reversed field pinch (RFP) magnetic configuration, and has made significant progress in understanding and improving confinement and in controlling plasma stability. A big leap with respect to previous knowledge and expectations on RFP physics and performance has been made by RFX-mod since the last 2006 IAEA Fusion Energy Conference. A new self-organized helical equilibrium has been experimentally achieved ( the Single Helical Axis-SHAx-state), which is the preferred state at high current. Strong core electron transport barriers characterize this regime, with electron temperature gradients comparable to those achieved in tokamaks, and by a factor of 4 improvement in confinement time with respect to the standard RFP. RFX-mod is also providing leading edge results on real-time feedback control of MHD instabilities, of general interest for the fusion community.
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| 2. |
- Sodergren, Erica, et al.
(författare)
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The genome of the sea urchin Strongylocentrotus purpuratus.
- 2006
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 314:5801, s. 941-52
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Tidskriftsartikel (refereegranskat)abstract
- We report the sequence and analysis of the 814-megabase genome of the sea urchin Strongylocentrotus purpuratus, a model for developmental and systems biology. The sequencing strategy combined whole-genome shotgun and bacterial artificial chromosome (BAC) sequences. This use of BAC clones, aided by a pooling strategy, overcame difficulties associated with high heterozygosity of the genome. The genome encodes about 23,300 genes, including many previously thought to be vertebrate innovations or known only outside the deuterostomes. This echinoderm genome provides an evolutionary outgroup for the chordates and yields insights into the evolution of deuterostomes.
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| 3. |
- Alfier, A., et al.
(författare)
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Energy confinement in high current RFX-mod plasmas
- 2007
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Ingår i: 34th EPS Conference on Plasma Physics 2007, EPS 2007 - Europhysics Conference Abstracts. - 9781622763344 ; , s. 415-418
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Konferensbidrag (refereegranskat)
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| 4. |
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| 5. |
- Annibaldi, Silvia Valeria, et al.
(författare)
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Strong transport reduction in the helical core of the reversed-field pinch
- 2007
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Ingår i: Physics of Plasmas. - : AIP Publishing. - 1070-664X .- 1089-7674. ; 14:11, s. 112515-
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Tidskriftsartikel (refereegranskat)abstract
- An explanation of the strong heating observed in the core of a reversed-field pinch in the quasi-single-helicity state is presented. A magnetic island is formed, in which the heat transport coefficient is much smaller than in the surrounding chaotic sea, because of the formation of well defined magnetic surfaces. The values of the thermal conductivity obtained with the M1TEV [F. Porcelli , Phys. Rev. Lett 82, 1458 (1999)] two-dimensional transport code are in very good agreement with the estimates of the ion diffusion coefficient inside the island, given by a Hamiltonian guiding center code. Moreover, the values of thermal conductivity are in the tokamak range, and are consistent with the peak temperatures measured in the Reversed Field eXperiment [P. Sonato , Fusion Eng. Des. 66-68, 161 (2003)] at Consorzio RFX, Padova, Italy. The effect of the island width and the different powers deposited inside the island on the final temperature peak are also investigated.
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| 6. |
- Annibaldi, Silvia Valeria, et al.
(författare)
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Excitation of beta-induced Alfvén eigenmodes in the presence of a magnetic island
- 2007
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Ingår i: Plasma Physics and Controlled Fusion. - : IOP Publishing. - 0741-3335 .- 1361-6587. ; 49:4, s. 475-483
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Tidskriftsartikel (refereegranskat)abstract
- Observation of magnetic activity in several discharges in the Frascati Tokamak Upgrade has revealed high-frequency oscillations that accompany the development of large magnetic islands in ohmic plasmas. The frequency of these oscillations is one order of magnitude above the typical island rotation frequency and one order of magnitude below the toroidicity-induced gap of the shear-Alfvén continuum. By writing a precise dispersion relation, we interpret these modes as beta-induced Alfvén eigenmodes, i.e. Alfvén eigenmodes located in the low frequency gap which is caused by finite compressibility.
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| 7. |
- Carlini, Valeria P., et al.
(författare)
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Melanin-concentrating hormone (MCH) reverts the behavioral effects induced by inescapable stress
- 2006
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Ingår i: Peptides. - : Elsevier BV. - 0196-9781 .- 1873-5169. ; 27:9, s. 2300-2306
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this work was to investigate if MCH modifies the feeding and freezing responses in rats exposed to stressful stimuli. We used a basic version of contextual fear, where one group of rats were placed in a novel environment and two different groups were exposed to footshock paradigms, one of them escapable and the other one inescapable. At the end of each treatment, freezing and feeding were measured. Only the animals exposed to inescapable footshock paradigm showed significant increase in the food intake and freezing behavior in comparison to the control animals. The MCH administration (intra-hippocampal or intra-amygdaline) reverted these effects elicited by inescapable footshock. Results presented in this paper lead us to the assumption that the anxiolytic effect of the peptide is responsible for the reversion of the IS effects.
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| 8. |
- Carlini, Valeria P., et al.
(författare)
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Obestatin improves memory performance and causes anxiolytic effects in rats
- 2007
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Ingår i: Biochemical and Biophysical Research Communications - BBRC. - : Elsevier BV. - 0006-291X .- 1090-2104. ; 352:4, s. 907-912
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Tidskriftsartikel (refereegranskat)abstract
- Obestatin is a peptide hormone that is derived from the same polypeptide precursor (preprogrelin) as ghrelin, but it acts in opposing way on ingestive behavior. Our previous studies showed that ghrelin affects memory and anxiety. Here, we studied the possible effects of icv obestatin injection in rats upon memory retention (using two different paradigms), anxiety like behavior (plus maze test), and food intake. Obestatin induces an increase in the percentage of open arms entries (Obestatin 3.0 nmol/rat: 61.74 ± 1.81), and percentage of time spent in open arms (Obestatin 3.0 nmol/rat: 72.07 ± 4.21) in relation to the control (33.31 ± 1.54; 25.82 ± 1.68), indicating an anxiolytic effect. The two doses of obestatin increased latency time in a step down test and the percentage time of novel object exploration, suggesting that the peptide influences learning and memory processes that involve the hippocampus and the amygdala. This report provides evidence indicating that obestatin effects are functionally opposite on anxiety and hunger to the ghrelin effects, while both these related peptides increase memory retention.
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| 9. |
- Carlini, Valeria P., et al.
(författare)
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Selective serotonin reuptake inhibitor (fluoxetine) decreases the effects of ghrelin on memory retention and food intake
- 2007
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Ingår i: Regulatory Peptides. - : Elsevier BV. - 0167-0115 .- 1873-1686. ; 140:1-2, s. 65-73
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Tidskriftsartikel (refereegranskat)abstract
- Ghrelin (Ghr) is an appetite stimulating hormone that is produced peripherally, by the stomach, and centrally as well. Previous investigations show that Ghr increases food intake and memory retention in rats, and that extra-hypothalamic structures, such as the hippocampus, participate in these effects. In the present work we analyzed the effect on food intake and memory retention induced by Ghr after serotonin (5-HT) availability modification at the serotoninergic synapses. Animals only treated with a selective serotonin reuptake inhibitor (SSRI), fluoxetine (FLU) 5 mg/kg or clomipramine (CLO) 2.5 and 5 mg/kg, showed a significant reduction in both food intake and memory retention. On the contrary, Ghr administration induces a significant increase in food intake and a dose-dependent increase in short and long term memory retention. When the animals were treated with FLU prior to Ghr injection, the food intake induced, as well as the expression of short and long term memory retention, was decreased. In conclusion, evidence presented in this paper suggests that the effects of Ghr on both feeding and memory retention in extra-hypothalamic structures such as the hippocampus, could depend on the availability of 5-HT.
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| 10. |
- Carvajal, Pedro, et al.
(författare)
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Central ghrelin increases anxiety in the Open Field test and impairs retention memory in a passive avoidance task in neonatal chicks
- 2009
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Ingår i: Neurobiology of Learning and Memory. - : Elsevier. - 1074-7427 .- 1095-9564. ; 91:4, s. 402-407
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Tidskriftsartikel (refereegranskat)abstract
- Ghrelin (Grh) is an endogenous ligand for the growth hormone secretagogue receptor. Although Ghr stimulates feeding in rats, it inhibits feeding in neonatal chicks. However, little is known about other central behavioral effects of Ghr. Therefore, we investigated the Ghr effects, injected intracerebroventricularly, on anxiety and memory retention of neonatal chicks in an Open Field test and in a one-trial passive avoidance task, respectively. In the Open Field test, the administration of Ghr in a dose-dependent manner increased the latency to ambulate but decreased ambulation activity, indicating an anxiogenic effect. Furthermore, chicks trained on a passive avoidance task and injected with a dose of 30pmol of Ghr immediately after training showed an impairment of memory retention. However, there were no significant effects on the number of pecks during the pretraining, training, retention and discrimination. In addition, different doses of Ghr produced an inhibition in food intake at different times after injection. Our results indicate that Ghr induces anxiogenesis in chicks. Moreover, we have shown for the first time that Ghr can decrease memory retention in a non-mammalian species, suggesting that Ghr may play an important role in the processes of memory retention in birds.
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