1,932 research outputs found
Fluctuating parts of nuclear ground state correlation energies
Background: Heavy atomic nuclei are often described using the
Hartree-Fock-Bogoliubov (HFB) method. In principle, this approach takes into
account Pauli effects and pairing correlations while other correlation effects
are mimicked through the use of effective density-dependent interactions.
Purpose: Investigate the influence of higher order correlation effects on
nuclear binding energies using Skyrme's effective interaction.
Methods: A cut-off in relative momenta is introduced in order to remove
ultraviolet divergences caused by the zero-range character of the interaction.
Corrections to binding energies are then calculated using the
quasiparticle-random-phase approximation (QRPA) and second order many-body
perturbation theory (MBPT2).
Result: Contributions to the correlation energies are evaluated for several
isotopic chains and an attempt is made to disentangle which parts give rise to
fluctuations that may be difficult to incorporate on the HFB level. The
dependence of the results on the cut-off is also investigated.
Conclusions: The improved interaction allows explicit summations of
perturbation series which is useful for the description of some nuclear
observables. However, refits of the interaction parameters are needed to obtain
more quantitative results
Genetic Assessment of Salmon and Sea Trout Stocking in a Baltic Sea River
Microsatellite DNA variation were used to assess the outcome of stocking salmon and trout in River Saevara, N Sweden. No information on pre-stocking genetic composition of salmon and trout in R Saevara was available. In two year classes of salmon smolt microsatellite data indicated that post-stocking genetic composition differed markedly (Fst = 0.048) from the main donor strain, Byskeaelven salmon, and from other Gulf of Bothnia salmon stocks (Fst 0.047- 0.132). The STRUCTURE program failed to detect any sub structuring within Saevara salmon. It was concluded that only minor introgression estimated to a proportion of 0.11 (95% CI 0.07 - 0.16) has occurred in salmon. Sea migrating trout showed overall low differentiation among populations with maximum Fst of 0.03 making analysis more cumbersome than in salmon. Still, the Saevara trout deviated significantly from potential donor populations and structure software supported that majority of trout in Saevara formed a distinct genetic population. Admixture was more extensive in trout and estimated to 0.17 (95% CI 0.10 - 0.25)
Sound radiation and sound insulation performances of maritime bulkheads
The research of materials matching low weight and high resistance has always been a key factor in the shipbuilding industry to increase performances and loading capacity. Nowadays, other issues add up to economical convenience, and building quiet ships is important not only for passengers and cabin crew, but also to make harbor areas more comfortable and to respect the aquatic environment. In this context, using sandwich or composite materials must be carefully evaluated and the sound insulation performances must be considered throughout all stages of the design process. This work presents some evaluations about the sound insulation performances of a ribbed fiberglass bulkhead and of a balsa-core sandwich bulkhead. In particular, the bending stiffness and the sound transmission loss obtained by sound transmission suites and mobility measurements are provided. From such measurements it has also been possible to determine the radiation efficiency of the structures, whose optimization is particularly important when a reduction of the noise pollution is required
Impact of Genetic Polymorphisms on the Smoking-related Risk of Periodontal Disease: the Population-based Study SHIP
Periodontitis is a bacterial inflammatory disease leading to attachment loss with the consequence of tooth loss. There exists a multifactorial risk pattern including bacterial challenge, smoking, age, sex, diabetes, socio-economic and genetic factors. Smoking has the highest impact on the course of the disease modulated by all the other factors. Here, we report the relationship between smoking and the polymorphisms of genetic polymorphisms inflicted in the pathogenesis
Counterflow dielectrophoresis for trypanosome enrichment and detection in blood
Human African trypanosomiasis or sleeping sickness is a deadly disease endemic in sub-Saharan Africa, caused by single-celled protozoan parasites. Although it has been targeted for elimination by 2020, this will only be realized if diagnosis can be improved to enable identification and treatment of afflicted patients. Existing techniques of detection are restricted by their limited field-applicability, sensitivity and capacity for automation. Microfluidic-based technologies offer the potential for highly sensitive automated devices that could achieve detection at the lowest levels of parasitemia and consequently help in the elimination programme. In this work we implement an electrokinetic technique for the separation of trypanosomes from both mouse and human blood. This technique utilises differences in polarisability between the blood cells and trypanosomes to achieve separation through opposed bi-directional movement (cell counterflow). We combine this enrichment technique with an automated image analysis detection algorithm, negating the need for a human operator
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