Lieb-Liniger gas in a constant force potential

We use Gaudin's Fermi-Bose mapping operator to calculate exact solutions for the Lieb-Liniger model in a linear (constant force) potential (the constructed exact stationary solutions are referred to as the Lieb-Liniger-Airy wave functions). The ground state properties of the gas in the wedge-like trapping potential are calculated in the strongly interacting regime by using Girardeau's Fermi-Bose mapping and the pseudopotential approach in the $1/c$-approximation ($c$ denotes the strength of the interaction). We point out that quantum dynamics of Lieb-Liniger wave packets in the linear potential can be calculated by employing an $N$-dimensional Fourier transform as in the case of free expansion

Biocompatibility of a new nanomaterial based on calcium silicate implanted in subcutaneous connective tissue of rats

The aim of the study was to investigate rat connective tissue response to a new calcium silicate system 7, 15, 30 and 60 days after implantation. Twenty Wistar albino male rats received two tubes half-filled with a new calcium silicate system (NCSS) or MTA in subcutaneous tissue. The empty half of the tubes served as controls. Five animals were sacrificed after 7, 15, 30 and 60 days and samples of the subcutaneous tissue around implanted material were submitted to histological analysis. The intensity of inflammation was evaluated based on the number of inflammatory cells present. Statistical analysis was performed using one way ANOVA and Holm Sidak's multiple comparison tests. Mild to moderate inflammatory reaction was observed after 7, 15 and 30 days around a NCSS while mild inflammatory reaction was detected after 60 days of implantation. In the MTA group, mild to moderate inflammatory reaction was found after 7 and 15 days while mild inflammatory reaction was present after 30 and 60 days. There was no statistically significant difference in the intensity of inflammatory reactions between the tested materials and control groups in any experimental period (ANOVA p>0.05). Regarding the intensity of inflammatory reactions at different experimental periods, a statistically significant difference was observed between 7 and 30 days, 7 and 60 days and 15 to 60 days for both materials. For the controls, a statistically significant difference was found between 7 and 60 days and 15 and 60 days of the experiment (Holm Sidak < p 0.001). Subcutaneous tissue of rats showed good tolerance to a new calcium silicate system. Inflammatory reaction was similar to that caused by MTA. [Projekat Ministarstva nauke Republike Srbije, br. 172026

Exact solution for a fermion in the background of a scalar inversely linear potential

The problem of a fermion subject to a general scalar potential in a two-dimensional world is mapped into a Sturm-Liouville problem for nonzero eigenenergies. The searching for possible bounded solutions is done in the circumstance of power-law potentials. The normalizable zero-eigenmode solutions are also searched. For the specific case of an inversely linear potential, which gives rise to an effective Kratzer potential, exact bounded solutions are found in closed form. The behaviour of the upper and lower components of the Dirac spinor is discussed in detail and some unusual results are revealed.Comment: 13 pages, 6 figure

Confinement of spinless particles by Coulomb potentials in two-dimensional space-time

The problem of confinement of spinless particles in 1+1 dimensions is approached with a linear potential by considering a mixing of Lorentz vector and scalar couplings. Analytical bound-states solutions are obtained when the scalar coupling is of sufficient intensity compared to the vector coupling.Comment: 14 pages, 2 figure

Possibility of afforestation of halomorphic soils in Vojvodina

Pošumljavanje halomorfnih tala u Vojvodini predstavlja poseban problem obzirom na vrlo nisku produktivnost kao posljedicu niza nepovoljnih svojstava toga stanišnog tipa. Niska produktivnost određuje mogućnost, razinu i karakter korištenja toga stanišnog tipa u šumarstvu. U osnovi, pošumljavanje na tome stanišnom tipu predstavlja prostornu infrastrukturnu investiciju u smislu poboljšanja strukture šumskog fonda i porasta ukupnog biološkog potencijala. Osnivanje šumskih nasada u cilju dobivanja drvne mase nema ekonomskog opravdanja. Razlog tome je niska produktivnost, karakteristična mozaičnost, a time i nemogućnost korištenja u šumarstvu, tako da je na ovom stanišnom tipu osnovna funkcija ekološka.The afforestation of halomorphic soils in Vojvodina is a special problem considering the very low productivity, a consequence of a series of unfavourable properties of this site type. Low productivity determines the potential, level and character of this site type utilisation in forestry. The afforestation on this site type is basically a spatial infrasructural investment in the sense of improving the growing stock structure and the increase of the total biological potential. The establishment of forest plantations aimed at obtaining timber is not economically justified. The reasons for this are the low productivity, the characteristic mosaic pattern, and, through this, the inadequacy of using these sites forest exploitation. Accordingly, this site type should mainly have ecological functions

Exact closed-form solutions of the Dirac equation with a scalar exponential potential

The problem of a fermion subject to a general scalar potential in a two-dimensional world for nonzero eigenenergies is mapped into a Sturm-Liouville problem for the upper component of the Dirac spinor. In the specific circumstance of an exponential potential, we have an effective Morse potential which reveals itself as an essentially relativistic problem. Exact bound solutions are found in closed form for this problem. The behaviour of the upper and lower components of the Dirac spinor is discussed in detail, particularly the existence of zero modes.Comment: 16 pages, 3 figure

Possibilities for using agricultural areas for the cultivation of poplars in the hilly and mountainous regions of the Republic of Serbia

Brojni manji ili već vodotoci rijeka i rječica u Republici Srbiji obrasli su fragmentima aluvijalno higrofilnih šuma i predstavljaju potencijal za proširenje šumskog fonda. Problem predstavlja usitnjenost parcela koje su korištene za uzgajanje poljoprivrednih kultura i u privatnom su vlasništvu. Poseban značaj podizanja aluvijalnih-higrofilnih šuma uz ove vodotoke je u povećanju ukupne površine pod šumama u Republici Srbiji, čime se posredno pospješuje održivi razvoj šumskih ekosistema, stabilnost poljoprivredne proizvodnje i zaštita životne sredine. Uz međe okolnih parcela od prirode se javljaju fragmenti nekadašnjih šuma, koji ukazuju na visok stupanj utjecaja antropogenog čimbenika, kao i na činjenicu da je na tim površinama bila autohtona šumska vegetacija. U radu su istraživana svojstva tala od značaja za uzgajanje selektiranih sorti crnih topola u plićaku rijeke Rasine. Izdvojena je pjeskovita i ilovasta forma fluvisola. Izdvojene sistematske jedinice tala su formirane u priobalnom genetičkom dijelu plićaka ove rijeke. Razlika između izdvojenih sistematskih jedinica tla je u sadržaju praha i gline, teksturnoj klasi i sadržaju odnosno tipu akumulacije organske tvari u tlu.Numerous smaller and larger river streams in Serbia are covered by the fragments of alluvial hygrophillous forests presenting a potential for an extension of the forest stock. Along with the private ownership of the land, there is also the problem of land fragmentation due to the use of the land for agriculture. The establishment of alluvial hygrophillous forests along these streams would enlarge the total forest area in the Republic, which would indirectly promote the sustainable development of the forest ecosystems, the stability of agriculture, and the protection of the environment. Along the margins of the surrounding land areas, the fragments of the past forests naturally return. This confirms a high degree of influence of the anthropogenetic factor, and the fact that autochthonous forest vegetation used to cover these areas. A special place in the enlargement of the growing stock of the Republic of Serbia is taken by the selected species of black poplars due to their fast growth, height increment and the multiple purpose of poplar timber. The many years of the research on the numerous factors influencing the production of the poplar wood mass resulted in the conclusion that a successful production requires the following most important steps: choice of species, choice of habitat (particularly soil), and the selection of the suitable technologies for the establishment, growth, and protection of the plantations

Nonleptonic Ω−\Omega^{-} decays and the Skyrme model

Nonleptonic $\Omega^{-}$ decay branching ratios are estimated by means of the QCD enhanced effective weak Hamiltonian supplemented by the SU(3) Skyrme model used to estimate the nonperturbative matrix elements. The model has only one free parameter, namely the Skyrme charge $e$, which is fixed through the experimental values of the octet-decuplet mass splitting $\Delta$ and the axial coupling constant $g_{A}$. The whole scheme is equivalent to that which works well for the nonleptonic hyperon decays. The ratios of calculated amplitudes are in agreement with experiment. However, the absolute values are about twice too large if short-distance corrections and only ground intermediate states are included.Comment: 4 pages, 1 figure, 1 table, version to appear in Phys.Rev.

Bounded solutions of neutral fermions with a screened Coulomb potential

The intrinsically relativistic problem of a fermion subject to a pseudoscalar screened Coulomb plus a uniform background potential in two-dimensional space-time is mapped into a Sturm-Liouville. This mapping gives rise to an effective Morse-like potential and exact bounded solutions are found. It is shown that the uniform background potential determinates the number of bound-state solutions. The behaviour of the eigenenergies as well as of the upper and lower components of the Dirac spinor corresponding to bounded solutions is discussed in detail and some unusual results are revealed. An apparent paradox concerning the uncertainty principle is solved by recurring to the concepts of effective mass and effective Compton wavelength.Comment: 15 pages, 7 figure