Standardisation of Environmental Enrichment for Laboratory Mice and Rats: Utilisation, Practicality and Variation in Experimental Results

Rats and mice are the most commonly used species as laboratory animal models of diseases in biomedical  research. Environmental factors such as cage size, number of cage mates and cage structure such as environmental  enrichment can affect the physiology and behavioural development of laboratory animals and  their well-being throughout their lives. Therefore compromising the animals’ well-being due to inadequate  environmental conditions would diminish the value of the research models. In order to improve laboratory  animals’ well-being and promote the quality of animal based biomedical research, it is fundamentally  important that the environment of the animals meets the animals’ species typical behavioural needs. Standardisation  of environmental enrichment for laboratory rats and mice therefore should provide possibilities  for the animals to engage in at least the essential behavioural needs such as social contact, nest building,  exploring and foraging. There is a wide variety of environmental enrichment items commercially available  for laboratory mice and rats. However, how these items are used by the animals, their practicality in the  laboratory and whether these enrichments might lead to increased variation in experimental results have  not been widely assessed. In this study, we implemented two standardised enrichment items (shelters, nesting  materials) for rats and mice at different animal units. We instructed the animal care staff in monitoring  the use of enrichment items by the animals by means of a daily score sheet system. The animal staff ’s  viewpoint on practicality of the standardised enrichment program was assessed with a monthly score sheet  survey. Also we assessed whether the enriched environment affected breeding results and contributed to an  increase in variation of experimental data from several participating current studies. Our results show that  the animals readily used the provided enrichment items. A slight increase in workload for the animal staff  was reported. However, the overall judgement was mainly reported as good. Breeding results and variation  in experimental data did not reveal differences as compared to data from previous housing and/or non enriched  housing conditions. Overall, the results indicate that standard environmental enrichment that is species  appropriate may enhance the animal’s well-being without undesirable side effects on the experimental  outcome and daily working routine of the animal care staff.

Tame Functions with strongly isolated singularities at infinity: a tame version of a Parusinski's Theorem

Let f be a definable function, enough differentiable. Under the condition of having strongly isolated singularities at infinity at a regular value c we give a sufficient condition expressed in terms of the total absolute curvature function to ensure the local triviality of the function f over a neighbourhood of c and doing so providing the tame version of Parusinski's Theorem on complex polynomials with isolated singularities at infinity.Comment: 20 page

Non-persistente virusoverdracht door bladluizen in bloembollen

Dit driejarig onderzoeksproject naar non-persistente virusoverdracht door bladluizen in bloembollen heeft direct toepasbare kennis en gewasbeschermingsadviezen opgeleverd, maar ook heldere adviezen voor zowel de chemische als biologische bestrijding van virusoverdracht door bladluizen. Deze adviezen vormen de basis voor verder onderzoek om uiteindelijk de non-persistente virusverspreiding door bladluizen nog effectiever te kunnen bestrijden

On the inertia of heat

Does heat have inertia? This question is at the core of a long-standing controversy on Eckart's dissipative relativistic hydrodynamics. Here I show that the troublesome inertial term in Eckart's heat flux arises only if one insists on defining thermal diffusivity as a spacetime constant. I argue that this is the most natural definition, and that all confusion disappears if one considers instead the space-dependent comoving diffusivity, in line with the fact that, in the presence of gravity, space is an inhomogeneous medium.Comment: 3 page

Trends in alcohol use among Hawai‘i adolescents

It is important to review trends in youth alcohol use over time in order to effectively tailor prevention programs to address those trends. This article reviews data on alcohol use behaviors from the Centers for Disease Control and Prevention\u27s Youth Risk Behavior Survey in Hawai‘i from 1993 to 2007. Five alcohol use indicators were examined and stratified by grade level, from 9th grade through 12th grade. Significant drops in nearly all indicators are seen among 9th through 11th graders, but not among 12th graders. This suggests that Hawai‘i youth are responding well to anti-alcohol messaging as young teens, but a different approach may be needed to target older teens

Fourier Magnetic Imaging with Nanoscale Resolution and Compressed Sensing Speed-up using Electronic Spins in Diamond

Optically-detected magnetic resonance using Nitrogen Vacancy (NV) color centres in diamond is a leading modality for nanoscale magnetic field imaging, as it provides single electron spin sensitivity, three-dimensional resolution better than 1 nm, and applicability to a wide range of physical and biological samples under ambient conditions. To date, however, NV-diamond magnetic imaging has been performed using real space techniques, which are either limited by optical diffraction to 250 nm resolution or require slow, point-by-point scanning for nanoscale resolution, e.g., using an atomic force microscope, magnetic tip, or super-resolution optical imaging. Here we introduce an alternative technique of Fourier magnetic imaging using NV-diamond. In analogy with conventional magnetic resonance imaging (MRI), we employ pulsed magnetic field gradients to phase-encode spatial information on NV electronic spins in wavenumber or k-space followed by a fast Fourier transform to yield real-space images with nanoscale resolution, wide field-of-view (FOV), and compressed sensing speed-up.Comment: 31 pages, 10 figure

Andreev reflection spectroscopy of the heavy-fermion superconductor CeCoIn5_5 along three different crystallographic orientations

Andreev reflection spectroscopy has been performed on the heavy-fermion superconductor (HFS) CeCoIn$_5$ single crystals along three different crystallographic orientations, (001), (110), and (100), using Au tips as counter-electrodes. Dynamic conductance spectra are reproducible over wide temperature ranges and consistent with each other, ensuring the spectroscopic nature. Features common to all directions are: i) asymmetric behaviors of the background conductance, which we attribute to the emerging coherent heavy-fermion liquid; ii) energy scales (~1 meV) for conductance enhancement due to Andreev reflection; iii) magnitudes of enhanced zero-bias conductance (10 - 13 %). These values are an order of magnitude smaller than the predicted value by the Blonder-Tinkham-Klapwijk (BTK) theory, but comparable to those for other HFSs. Using the d-wave BTK model, we obtain an energy gap of ~ 460 ueV. However, it is found that extended BTK models considering the mismatch in Fermi surface parameters do not account for our data completely, which we attribute to the shift of spectral weight to low energy as well as to the suppressed Andreev reflection. A qualitative comparison of the conductance spectra with calculated curves shows a consistency with d$_{x^2-y^2}$-symmetry, providing the first spectroscopic evidence for the order parameter symmetry and resolving the controversy over the location of the line nodes.Comment: invited talk submitted to the 8th M2S conference to be held in Dresden Germany, July 9-14, 2006, 4 pages, 3 figure

Glasses in hard spheres with short-range attraction

We report a detailed experimental study of the structure and dynamics of glassy states in hard spheres with short-range attraction. The system is a suspension of nearly-hard-sphere colloidal particles and non-adsorbing linear polymer which induces a depletion attraction between the particles. Observation of crystallization reveals a re-entrant glass transition. Static light scattering shows a continuous change in the static structure factors upon increasing attraction. Dynamic light scattering results, which cover 11 orders of magnitude in time, are consistent with the existence of two distinct kinds of glasses, those dominated by inter-particle repulsion and caging, and those dominated by attraction. Samples close to the `A3 point' predicted by mode coupling theory for such systems show very slow, logarithmic dynamics.Comment: 22 pages, 18 figure

Hidden attractors in fundamental problems and engineering models

Recently a concept of self-excited and hidden attractors was suggested: an attractor is called a self-excited attractor if its basin of attraction overlaps with neighborhood of an equilibrium, otherwise it is called a hidden attractor. For example, hidden attractors are attractors in systems with no equilibria or with only one stable equilibrium (a special case of multistability and coexistence of attractors). While coexisting self-excited attractors can be found using the standard computational procedure, there is no standard way of predicting the existence or coexistence of hidden attractors in a system. In this plenary survey lecture the concept of self-excited and hidden attractors is discussed, and various corresponding examples of self-excited and hidden attractors are considered