Time-Dependent Density-Functional Theory for Superfluids

A density-functional theory is established for inhomogeneous superfluids at finite temperature, subject to time-dependent external fields in isothermal conditions. After outlining parallelisms between a neutral superfluid and a charged superconductor, Hohenberg-Kohn-Sham-type theorems are proved for gauge-invariant densities and a set of Bogolubov-Popov equations including exchange and correlation is set up. Earlier results applying in the linear response regime are recovered.Comment: 12 pages. Europhysics Letters, in pres

Collective excitations of a periodic Bose condensate in the Wannier representation

We study the dispersion relation of the excitations of a dilute Bose-Einstein condensate confined in a periodic optical potential and its Bloch oscillations in an accelerated frame. The problem is reduced to one-dimensionality through a renormalization of the s-wave scattering length and the solution of the Bogolubov - de Gennes equations is formulated in terms of the appropriate Wannier functions. Some exact properties of a periodic one-dimensional condensate are easily demonstrated: (i) the lowest band at positive energy refers to phase modulations of the condensate and has a linear dispersion relation near the Brillouin zone centre; (ii) the higher bands arise from the superposition of localized excitations with definite phase relationships; and (iii) the wavenumber-dependent current under a constant force in the semiclassical transport regime vanishes at the zone boundaries. Early results by J. C. Slater [Phys. Rev. 87, 807 (1952)] on a soluble problem in electron energy bands are used to specify the conditions under which the Wannier functions may be approximated by on-site tight-binding orbitals of harmonic- oscillator form. In this approximation the connections between the low-lying excitations in a lattice and those in a harmonic well are easily visualized. Analytic results are obtained in the tight-binding scheme and are illustrated with simple numerical calculations for the dispersion relation and semiclassical transport in the lowest energy band, at values of the system parameters which are relevant to experiment.Comment: 20 pages, 2 figures, 22 reference

Effect of lairage duration on some blood constituents and beef quality in bulls after long journey

Al fine di contribuire alla individuazione di un tempo adeguato di sosta al termine di un lungo trasporto, sono stati esaminati gli effetti di diverse durate della sosta al macello su alcuni parametri ematici e sulla qualit\ue0 della carne in bovini maschi interi sottoposti a viaggi commerciali di lunga durata. Lo studio \ue8 stato condotto su 39 vitelloni Limousine allevati nelle medesime condizioni presso un unica azienda situata nelle vicinanze di Saragoza (Spagna). Gli animali sono stati esaminati al termine di 5 viaggi commerciali dopo un tragitto di 2500 km, presso lo stabilimento di macellazione \u201cSan Giorgio\u201d di Gangi (Palermo). Il tempo di trasporto \ue8 stato pari a ore 53,6\ub110,9. Per i soggetti della prima, della terza e della quinta consegna, la durata della sosta \ue8 risultata compresa tra 24 e 36 ore, con una media pari a 31 ore (gruppo \u201cShort Lairage\u201d), mentre nella terza e nella quinta consegna la sosta \ue8 stata pari, rispettivamente, a 57 e 59 ore (gruppo \u201cLong Lairage\u201d). I risultati relativi all\u2019esame emocromo-citometrico, hanno evidenziato un effetto significativo (P>0,001) della durata della sosta pre-macellazione sia sul numero dei leucociti che sulle piastrine. La durata della sosta non ha mostrato avere nessun effetto significativo su globuli rossi, emoglobina ed ematocrito anche se l\u2019analisi della varianza per misure ripetute ha mostrato che, indipendentemente dalla durata della sosta, l\u2019ematocrito \ue8 variato significativamente dal momento dello scarico a quello della macellazione, aumentando durante tale periodo. L\u2019analisi statistica effettuata sui parametri ematochimici ha evidenziato un effetto significativo (P>0,05) della durata della sosta solo sull\u2019enzima CK e sul cortisolo. L\u2019enzima CK ha mostrato un incremento nel gruppo \u201cShort Lairage\u201d (33,2% vs 14,3%) mentre il Cortisolo ha mostrato una diminuzione nel gruppo \u201cLong Lairage\u201d (36,3% vs 3,8%). La durata della sosta non ha influenzato significativamente (P>0,05) l\u2019incidenza di lesioni lievi e gravi registrate sulle carcasse. Per quanto concerne la qualit\ue0 della carne, la durata della sosta ha influenzato significativamente il pHu, risultato pi\uf9 elevato (P>0,01) nel muscolo dei soggetti del gruppo \u201cLong Lairage\u201d; la luminosit\ue0 a 24h post mortem \ue8 risultata significativamente pi\uf9 elevata (P>0,05) nei soggetti del gruppo \u201cShort Lairage\u201d rispetto a quelli del gruppo \u201cLong Lairage\u201d, mentre gli indici del rosso e del giallo sono risultati essere maggiori in quest\u2019ultimo gruppo. Il calo peso dopo cottura \ue8 risultato significativamente minore (P>0,01) nel gruppo \u201cShort Lairage\u201d, lo stesso gruppo \u201cShort Lairage\u201d ha fatto registrare carni significativamente pi\uf9 tenere (P>0,01). Dai risultati ottenuti emerge come la durata della sosta pre-macellazione dopo un trasporto di lunga durata pu\uf2 influenzare il quadro ematologico e la qualit\ue0 della carne. Nel complesso \ue8 emerso che prolungare la sosta oltre le 36 ore non provoca alcun beneficio per il benessere dell\u2019animale e rischia di peggiorare la qualit\ue0 della carne. Nel caso di trasporti cos\uec lunghi come quelli esaminati sarebbe opportuno una migliore organizzazione della logistica al fine di ridurre il tempo di attesa degli animali prima della macellazione.With the aim to contribute to determine an adequate resting time for cattle after long transportation, the effects of different lairage time on some haematic parameters and meat quality of bulls subjected to long commercial journeys were investigated. Thirty-nine Limousine bulls supplied by one farm located near to Saragoza (Spain) were examined after 5 consignments at the final destination, after a journey of 2.550 km, of the \u201cSan Giorgio\u201d abattoir (Palermo, Italy). Transport time was of 53.6 \ub1 10.9 h; lairage duration for bulls of the 1st, 3rd and 5th consignments was of 31 h on average (\u201cShort Lairage\u201d group), whereas, for those of the 2nd and 4th consignments, was of 59 and 57 h, respectively (\u201cLong Lairage\u201d group). As regards the blood cell counts, data showed a significant effect (P< 0.001) of the lairage duration on leukocyte and platelet counts. No significant effect was observed for erythrocyte count, haemoglobin and hematocrit in relation to the lairage duration, even if the repeated measure analysis of variance showed that, irrespectively to the lairage duration, the hematocrit increased significantly from the unloading to the slaughter. Haematological parameters showed a significant (P< 0.05) effect of the lairage time only on CK and Cortisol. CK enzyme showed an increase in the \u201cShort Lairage\u201d group (33.2% vs. 14.3%) whereas, Cortisol showed a decrease in the \u201cLong Lairage\u201d group (36.3% vs. 3.8%). The different lairage duration did not significantly (P> 0.05) affect the incidence of slight and severe bruises of carcass. As regard meat quality, lairage duration has significantly influenced the pHu which was higher (P< 0.01) in the muscle of the animals of the \u201cLong Lairage\u201d group, the luminosity at 24h post mortem which was significantly higher (P< 0.05) in animals of the \u201cShort Lairage\u201d group and the red and yellow indices which were higher in the \u201cLong Lairage\u201d group. \u201cShort Lairage\u201d group showed lower (P< 0.01) value of cooking loss and higher (P< 0.01) value of tenderness. Data show that pre-slaughter lairage duration after a long transport may influence the blood parameters as well as meat quality. On the whole, the increase of the lairage duration over 36 h does not determine any benefit for the animal well-being whereas it can cause a reduction of the beef quality. For so long transports, it should be better an adequate organization of the facilities in order to diminish the pre-slaughter lairage duration

Rosemary extract (Rosmarinus officinalis L.) supplementation into the diet of Nero Siciliano pigs: effects on lipid oxidation

During the growing-fattening period (93 days; ILW 33.5±6 kg to FLW 67±3 kg), 30 Nero Siciliano pigs were fed on a basal diet supplemented with (ROX group) or not (CTR group) a rosemary extract (1g?kg-1). At 1, 3 and 5 days after slaughtering, the oxidative stability of the Longissimus dorsi muscle was determined by using TBArs test. Moreover, on the individual samples of the muscle the lipid content, the fatty acid and the sterol composition were determined; the acidic composition of the lard, removed from backfat, was also studied. Data were subjected to ANOVA. The fat content of the muscle was unaffected by the dietary treatment as well as the oxidative stability whereas, significant differences (P²0.01) were observed for the polyunsaturated fatty acid content which showed the highest values in the meat as well as in the lard of the ROX group; PUFA/SFA ratio was also significantly highest in the muscle (P=0.004) and in the lard (P=0.017) of the ROX group, testifying a possible antioxidative activity of the rosemary extract. The sterol fraction (cholesterol, cholestanol, stigmasterol, beta-sitosterol and delta 5-avenasterol) of the Longissimus dorsi muscle was unaffected by the rosemary supplementation; a significant difference was observed only for the campesterol (CTR group=1.08, ROX group=0.90; P = 0.021)

Proteins of the milk and genetic variants in certain sheep populations of Sicily (Barbaresca-Siciliana)

International audienc

Probing the energy bands of a Bose-Einstein condensate in an optical lattice

We simulate three experimental methods which could be realized in the laboratory to probe the band excitation energies and the momentum distribution of a Bose-Einstein condensate inside an optical lattice. The values of the excitation energies obtained in these different methods agree within the accuracy of the simulation. The meaning of the results in terms of density and phase deformations is tested by studying the relaxation of a phase-modulated condensate towards the ground state.Comment: 5 pages, 5 figure

1D model for the dynamics and expansion of elongated Bose-Einstein condensates

We present a 1D effective model for the evolution of a cigar-shaped Bose-Einstein condensate in time dependent potentials whose radial component is harmonic. We apply this model to investigate the dynamics and expansion of condensates in 1D optical lattices, by comparing our predictions with recent experimental data and theoretical results. We also discuss negative-mass effects which could be probed during the expansion of a condensate moving in an optical lattice.Comment: RevTeX4, 8 pages, 10 figures, extended and revised versio

An interview with Marisa Michelini: IUPAP-ICPE medal, professor of physicseducation research at Udine University, GIREP President

The present interview was conceived and realized for the occasion of the first 45 years of endless Physics Education Research activity of Professor Marisa Michelini, a lifetime dedicated to innovate teaching and learning environments to all degrees of instruction, and to design institutional architectures, where rooting these innovations. The interview structure is inspired to the nature of scientific thinking, i.e. inducing more general understanding from concrete observations, in two manners. First, the interview focuses on (ten) topics drawing from three box-cases about physics education research and teachers education in scientific areas: innovations in teaching/learning environments; theoretical and methodological frameworks; and strategies and tools for institutional cooperation between schools and governing bodies to urge policy making. Each topic is introduced by observations, from which the interview questions are induced. Second, each question draws from Marisa Michelini’s contributions, to touch core topics at the heart of science education, science and society

Dynamical localization of matter wave solitons in managed barrier potentials

The bright matter wave soliton propagation through a barrier with a rapidly oscillating position is investigated. The averaged over rapid oscillations Gross-Pitaevskii (GP) equation is derived. It is shown that the soliton is dynamically trapped by the effective double-barrier. The analytical predictions for the soliton effective dynamics is confirmed by the numerical simulations of the full GP equation.Comment: 10 pages, 6 figure

Local-Field Theory of the BCS-BEC Crossover

We develop a self-consistent theory unifying the description of a quantum Fermi gas in the presence of a Fano-Feshbach resonance in the whole phase diagram ranging from BCS to BEC type of superfluidity and from narrow to broad resonances, including the fluctuations beyond mean field. Our theory covers a part of the phase diagram which is not easily accessible by Quantum Monte Carlo simulations and is becoming interesting for a new class of experiments in cold atoms