Location In Cage Research Articles

Effects of environmental enrichment on the behavior of shelter dogs

To determine the effect of food-toy enrichment combined with cage-behavior training on desirable behaviors in shelter dogs and adoption rates. Randomized controlled clinical trial. 107 dogs. Dogs placed up for adoption in a municipal shelter were randomly assigned to either an experimental group (n = 48) or control group (59). Experimental group subjects were exposed to an environmental enrichment and training protocol consisting of twice-daily cage-behavior training and daily provision of a food-filled toy. Cage-behavior training included operant conditioning via positive reinforcement of desirable behaviors, including approaching the front of the cage, sitting or lying, and remaining quiet when approached. Behavioral observations were performed by a blinded observer in a scan-sampling technique on day 0 (first day on adoption floor) and again on day 3 for experimental (n = 26) and control (32) dogs. Body posture, location in cage, and other behavioral parameters were recorded. Adoption information and behavioral observation data were compared between groups. Compared with the control group, the experimental group had a significantly greater percentage of dogs with an increase in desirable behaviors of sitting or lying down (17/26 [65%] vs 7/32 [22%]) and being quiet (9/26 [35%] vs 4/32 [13%]) and a significantly greater percentage of dogs with a decrease in the undesirable behavior of jumping (15/26 [57%] vs 3/32 [9%]). Location in cage, fearfulness, and eye contact were not significantly different between groups. Survival analysis revealed no significant difference in adoption rates between groups. Results suggested that enrichment programs improve desirable behaviors and decrease undesirable behavior in shelter dogs, which may enhance welfare.

Vacancy decay in endohedral atoms: the role of an atom's non-central position

We demonstrate that the Auger decay rate in an endohedral atom is very sensitive to the atom's location in the fullerene cage. Two additional decay channels appear in an endohedral system: (a) the channel due to the change in the electric field at the atom caused by the dynamic polarization of the fullerene electron shell by the Coulomb field of the vacancy and (b) the channel within which the released energy is transferred to the fullerene electron via the Coulomb interaction. The relative magnitude of the correction terms is dependent not only on the position of the doped atom but also on the transition energy ω. Additional enhancement of the decay rate appears for transitions whose energies are in the vicinity of the fullerene surface plasmons energies of high multipolarity. It is demonstrated that in many cases the additional channels can dominate the direct Auger decay resulting in pronounced broadening of the atomic emission lines. The case study, carried out for Sc2 +@C6 −80, shows that narrow autoionizing resonances in an isolated Sc2 + within the range ω = 30–45 eV are dramatically broadened if the ion is located strongly off the centre. Using the developed model, we carry out the quantitative analysis of the photoionization spectrum for the endohedral complex Sc3N@C80 and demonstrate that the additional channels are partly responsible for the strong modification of the photoionization spectrum profile detected experimentally by Müller et al (2007 J. Phys.: Conf. Ser. 88 012038).

The nuclear magnetic resonance line shapes of Xe in the cages of clathrate hydrates.

We report, for the first time, a prediction of the line shapes that would be observed in the (129)Xe nuclear magnetic resonance (NMR) spectrum of xenon in the cages of clathrate hydrates. We use the dimer tensor model to represent pairwise contributions to the intermolecular magnetic shielding tensor for Xe at a specific location in a clathrate cage. The individual tensor components from quantum mechanical calculations in clathrate hydrate structure I are represented by contributions from parallel and perpendicular tensor components of Xe-O and Xe-H dimers. Subsequently these dimer tensor components are used to reconstruct the full magnetic shielding tensor for Xe at an arbitrary location in a clathrate cage. The reconstructed tensors are employed in canonical Monte Carlo simulations to find the Xe shielding tensor component along a particular magnetic field direction. The shielding tensor component weighted according to the probability of finding a crystal fragment oriented along this direction in a polycrystalline sample leads to a predicted line shape. Using the same set of Xe-O and Xe-H shielding functions and the same Xe-O and Xe-H potential functions we calculate the Xe NMR spectra of Xe atom in 12 distinct cage types in clathrate hydrates structures I, II, H, and bromine hydrate. Agreement with experimental spectra in terms of the number of unique tensor components and their relative magnitudes is excellent. Agreement with absolute magnitudes of chemical shifts relative to free Xe atom is very good. We predict the Xe line shapes in two cages in which Xe has not yet been observed.

The molecular structure and electronic spectrum of the C@C 60 endohedral complex: An ab initio study

We performed ab initio quantum-chemical studies at the HF and B3LYP levels of theory to determine the geometry and electronic spectra of the C@C 60 complex. The STO-3G and 6-31G(d) basis sets were employed. Two different types of stable conformations for the endohedral atom related to the centers of five- and six-member rings were found. The estimated potential barrier between those conformations is small; under certain conditions, the endohedral atom can transfer from one location in the molecular cage to another. The influence of the location of endohedral carbon atom on the electronic spectrum of C 60 is discussed. © 2001 by Elsevier Science Inc.