Asymmetric Lineshape due to Inhomogeneous Broadening of the Crystal-Field Transitions in Mn12ac Single Crystals

The lineshape of crystal-field transitions in single crystals of Mn12ac molecular magnets is determined by the magnetic history. The absorption lines are symmetric and Gaussian for the non-magnetized state obtained by zero-field cooling (zfc). In the magnetized state which is reached when the sample is cooled in a magnetic field (fc), however, they are asymmetric even in the absence of an external magnetic field. These observations are quantitatively explained by inhomogeneous symmetrical (Gaussian) broadening of the crystal-field transitions combined with a contribution of off-diagonal components of the magnetic susceptibility to the effective magnetic permeability.Comment: 4 pages, 3 figure

On the 'Strong-Coupling' Generalization of the Bogoliubov Model

A generalized Bogoliubov model of the Bose gas in the ground state is proposed which properly takes into account both the long-range and short-range spatial boson correlations. It concerns equilibrium characteristics and operates with in-medium Schrodinger equations for the pair wave functions of bosons being the eigenfunctions of the second-order reduced density matrix. The approach developed provides reasonable results for a dilute Bose gas with arbitrary strong interaction between particles (the 'strong-coupling' case) and comes to the canonical Bogoliubov model in the weak-coupling regime.Comment: 6 pages, REVTEX, no figure

Strength of the Trilinear Higgs Boson Coupling in Technicolor Models

We discuss the strength of the trilinear Higgs boson coupling in technicolor (or composite) models in a model independent way. The coupling is determined as a function of a very general ansatz for the technicolor self-energy, and turns out to be equal or smaller than the one of the standard model Higgs boson depending on the dynamics of the theory. With this trilinear coupling we estimate the cross section for Higgs boson pair production at the LHC. This measurement is quite improbable in the case of a heavy standard model Higgs boson, but it will be even worse when this boson is dynamically generated.Comment: 20 pages, 4 figures, Typos correcte

Biochemical and haematological values in abattoir pigs with and without subclinical lesions

The biochemical and haematological profiles of 379 pigs with or without various gross pathological lesions in an abattoir in Zimbabwe were studied to see whether there were any differences between the levels of haematological and biochemical values, and health status (with and without pathological lesions). On the basis of observable gross pathology, 134 pigs were classified as having one or more subclinical lesions (liver milk spot, pneumonia, pleurisy, pericarditis, abscesses and arthritis). Seventy six of these were males and 58 females. There were observable sex differences in the mean haematological and biochemical values obtained. Erythrocyte counts showed significant differences in mean values (P < 0,05) among groups of pigs found with various pathological lesions. The biochemical values showed significant group differences for ALP, ALT. AST, and LDH.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat X Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.University of Zimbabwe Research Boardmn201

Climate change expected to drive habitat loss for two key herbivore species in an alpine environment

Aim Our first aim was to determine the environmental factors associated with two native Australian Lepidoptera species, Lomera caespitosae and Oncopera alpina, key herbivores of alpine and subalpine Poa grasses. Both species have been associated with areas of extensive grass death in Australian alpine regions, possibly affecting vegetation succession and recovery. Our second aim was to generate and evaluate potential distributional changes for both these moths and their host plants under scenarios of climate change. Location Alpine regions in south-eastern Australia. Methods We surveyed alpine regions in south-eastern Australia to compile presence–absence datasets for both moth species. We constructed ecological niche models from our survey data, in addition to predicting distributions of suitable host-plant species for the moths. Grass damage sites attributed to the moths were used additionally as independent test datasets to validate model performance. Future effects on species distributions under climate change scenarios were then investigated. Results The environmental factors affecting distributions differed between the moth species; for example, precipitation variables appeared to be important for L. caespitosae, while low winter–spring temperatures were expected to limit O. alpina. The findings were related to the presence of grass damage, which was greater in areas where species distributions overlapped. A declining trend in suitability was predicted for both herbivore species under climate change, while Poa spp. distributions were expected to be less influenced by climate change. Main conclusions The distributions of both moth species are more likely to be restricted by climate than host-plant availability. Predicted climate change effects are likely to put L. caespitosae under greater immediate risk of local extinction than O. alpina as a result of large areas of habitat loss by 2050

Linewidth of single photon transitions in Mn12_{12}-acetate

We use time-domain terahertz spectroscopy to measure the position and linewidth of single photon transitions in Mn$_{12}$-acetate. This linewidth is compared to the linewidth measured in tunneling experiments. We conclude that local magnetic fields (due to dipole or hyperfine interactions) cannot be responsible for the observed linewidth, and suggest that the linewidth is due to variations in the anisotropy constants for different clusters. We also calculate a lower limit on the dipole field distribution that would be expected due to random orientations of clusters and find that collective effects must narrow this distribution in tunneling measurements.Comment: 5 pages, accepted to Physical Review

Nonlocality and entanglement in a strange system

We show that the relation between nonlocality and entanglement is subtler than one naively expects. In order to do this we consider the neutral kaon system--which is oscillating in time (particle--antiparticle mixing) and decaying--and describe it as an open quantum system. We consider a Bell--CHSH inequality and show a novel violation for non--maximally entangled states. Considering the change of purity and entanglement in time we find that, despite the fact that only two degrees of freedom at a certain time can be measured, the neutral kaon system does not behave like a bipartite qubit system.Comment: 7 pages, 2 figures, extended versio

Theory of asymmetric non-additive binary hard-sphere mixtures

We show that the formal procedure of integrating out the degrees of freedom of the small spheres in a binary hard-sphere mixture works equally well for non-additive as it does for additive mixtures. For highly asymmetric mixtures (small size ratios) the resulting effective Hamiltonian of the one-component fluid of big spheres, which consists of an infinite number of many-body interactions, should be accurately approximated by truncating after the term describing the effective pair interaction. Using a density functional treatment developed originally for additive hard-sphere mixtures we determine the zero, one, and two-body contribution to the effective Hamiltonian. We demonstrate that even small degrees of positive or negative non-additivity have significant effect on the shape of the depletion potential. The second virial coefficient $B_2$, corresponding to the effective pair interaction between two big spheres, is found to be a sensitive measure of the effects of non-additivity. The variation of $B_2$ with the density of the small spheres shows significantly different behavior for additive, slightly positive and slightly negative non-additive mixtures. We discuss the possible repercussions of these results for the phase behavior of binary hard-sphere mixtures and suggest that measurements of $B_2$ might provide a means of determining the degree of non-additivity in real colloidal mixtures

A C/EBPα-Wnt connection in gut homeostasis and carcinogenesis

We explored the connection between C/EBPα (CCAAT/enhancer-binding protein α) and Wnt signaling in gut homeostasis and carcinogenesis. C/EBPα was expressed in human and murine intestinal epithelia in the transit-amplifying region of the crypts and was absent in intestinal stem cells and Paneth cells with activated Wnt signaling. In human colorectal cancer and murine APC(Min/+) polyps, C/EBPα was absent in the nuclear β-catenin-positive tumor cells. In chemically induced intestinal carcinogenesis, C/EBPα KO in murine gut epithelia increased tumor volume. C/EBPα deletion extended the S-phase cell zone in intestinal organoids and activated typical proliferation gene expression signatures, including that of Wnt target genes. Genetic activation of β-catenin in organoids attenuated C/EBPα expression, and ectopic C/EBPα expression in HCT116 cells abrogated proliferation. C/EBPα expression accompanied differentiation of the colon cancer cell line Caco-2, whereas β-catenin stabilization suppressed C/EBPα. These data suggest homeostatic and oncogenic suppressor functions of C/EBPα in the gut by restricting Wnt signaling

Present Limits on the Precision of SM Predictions for Jet Energies

We investigate the impact of theoretical uncertainties on the accuracy of measurements involving hadronic jets. The analysis is performed using events with a Z boson and a single jet observed in $p\bar{p}$ collisions at $\sqrt{s}$ = 1.96 TeV in 4.6 $\mathrm{fb^{-1}}$ of data from the Collider Detector at Fermilab (CDF). The transverse momenta (\pt) of the jet and the boson should balance each other due to momentum conservation in the plane transverse to the direction of the $p$ and $\bar{p}$ beams. We evaluate the dependence of the measured \pt-balance on theoretical uncertainties associated with initial and final state radiation, choice of renormalization and factorization scales, parton distribution functions, jet-parton matching, calculations of matrix elements, and parton showering. We find that the uncertainty caused by parton showering at large angles is the largest amongst the listed uncertainties. The proposed method can be re-applied at the LHC experiments to investigate and evaluate the uncertainties on the predicted jet energies. The distributions produced at the CDF environment are intended for comparison to those from modern event generators and new tunes of parton showering.Comment: Submitted to Nucl. Instr. and Meth.