144 research outputs found
Alpha-like quartet condensation and isovector pairing correlations in N=Z nuclei
We propose a simple quartet condensation model (QCM) which describes with
very high accuracy the isovector pairing correlations in self-conjugate nuclei.
The quartets have an alpha-like structure and are formed by collective
isovector pairs. The accuracy of the QCM is tested for N=Z nuclei for which
exact shell model diagonalizations can be performed. The calculations are done
with two isovector pairing forces, one extracted from standard shell model
interactions and the other of seniority type, acting, respectively, upon
spherical and axially-deformed single-particle states. It is shown that for all
calculated nuclei the QCM gives very accurate values for the pairing
correlations energies, with errors which do not exceed 1%. These results show
clearly that the correlations induced by the isovector pairing in
self-conjugate nuclei are of quartet type and also indicate that QCM is the
proper tool to calculate the isovector proton-neutron correlations in mean
field pairing models.Comment: 11 pages, two table
Pairing and alpha-like quartet condensation in N=Z nuclei
We discuss the treatment of isovector pairing by an alpha-like quartet
condensate which conserves exactly the particle number, the spin and the
isospin. The results show that the quartet condensate describes accurately the
isovector pairing correlations in the ground state of systems with an equal
number of protons and neutronsComment: 4 pages, to appear in Journal of Physics: Conference Serie
A STOCHASTIC MODELING FOR THE UNSTABLE FINANCIAL MARKETS
Considering the present economic context, the measurement of performances has become a permanent preoccupation for organizations, since the whole process is based on it, offering the necessary feedback to identify both the positive actions which have led to favorable results for the organization, and the negative ones, in order to correct them in the future. To do this, we have to measure what is most importantly to measure. Starting from these considerations, the present paper approaches from a theoretical and practical point of view the economic rate of return as the indicator which synthesizes best an organization’s financial-economic performance. We have calculated and analyzed the economic rate of return for a group of Ten Romanian Firms in the food industry, through different calculation relations, pointing out the advantages/disadvantages of each calculation method.belated integral, forward-backward stochastic equations, pathwise uniqueness, financial modeling.
Structure of the quartetting ground state of nuclei
The formal equivalence between the quartetting picture and the symmetry
restored BCS picture is established for the ground state correlations induced
by the general isovector-isoscalar pairing interaction. Multiple ground state
structures compatible with the particle number and isospin symmetries are
evaluated. The competition of isovector and isoscalar correlations is discussed
for the nuclei above Sn.Comment: 5 pages, 1 figur
Effects of the Hydroethanolic Extract of Lycopodium selago L. on Scopolamine-Induced Memory Deficits in Zebrafish
This scientific research focused on the production of hydroethanolic extract of the plant species Lycopodium selago L. (L. selago) by the ultrasound-assisted extraction (USAE) and the identification of biocompounds with high antioxidant activity is of interest for possible phytotherapeutic treatment against Alzheimer’s disease (AD). The extract was phytochemically analyzed to investigate polyphenols, flavonoids, and identify the sesquiterpenoid alkaloid huperzine A (HupA), which is known in the literature for its great relevance in AD. Evaluation and comparison of the antioxidant activity of the extract were performed by four complementary spectrophotometric methods (DPPH, FRAP, ABTS, ORAC). In vitro tests of the extract showed an excellent reciprocal link between the concentration of polyphenols and the measurement of the antioxidant activity of the extract with the sesquiterpenoid HupA. To confirm the antioxidant activity, L. selago hydroethanolic extract was administered in vivo to zebrafish (Danio rerio) with a pattern of scopolamine-induced cognitive impairment. Moreover, this study explored a possible correlation between the expression of oxidative stress markers in the brain tissue with the behavior of the scopolamine zebrafish model. In vivo tests showed that this fern could be used as a nutritional supply and as a phytotherapeutic method to prevent or treat various neurodegenerative diseases that call for high-nutritive-value medications
Hericium erinaceus (Bull.) Pers. Ethanolic Extract with Antioxidant Properties on Scopolamine-Induced Memory Deficits in a Zebrafish Model of Cognitive Impairment
Hericium erinaceus (H. erinaceus) is a rare and appreciated fungal species belonging to the division Basidiomycota used for centuries in traditional Chinese medicine for its medicinal value. This species of mushrooms brings the most diverse benefits for the human body, and can have beneficial effects for treating Alzheimer’s disease (AD). This study investigated whether ethanolic extract from the fungal biomass of H. erinaceus enhances cognitive function via the action on cholinergic neurons using the scopolamine (SCOP)-induced zebrafish (Danio rerio) model of memory impairment. The ethanolic extract from the fungal biomass of H. erinaceus was previously obtained using an ultrasonic extraction method (UE). The administration of H. erinaceus extract to zebrafish, with a pattern of AD induced by scopolamine, showed an improvement in memory evaluated by behavioral and biochemical tests on brain tissue. These results suggest that H. erinaceus has preventive and therapeutic potentials in managing memory deficits and brain oxidative stress in zebrafish with AD
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