Constructing Memory: The Vimy Memorial

The 75th anniversary of the battle of Vimy Ridge is also the 56th anniversary of the dedication of the Vimy Memorial. In the summer of 1936 over 100,000 people witnessed a ceremony which captured the imagination of the world and crystalized the Canadian memory of Vimy ridge. The historical reality of the battle was re-worked and reinterpreted in a conscious attempt to give purpose and meaning to an event which was to symbolize Canada’s coming-of-age as a nation

Neutrinos from Off-Shell Final States and the Indirect Detection of Dark Matter

We revisit the annihilation of dark matter to neutrinos in the Sun near the WW and tt kinematic thresholds. We investigate the potential importance of annihilation to WW* in a minimal dark matter model in which a Majorana singlet is mixed with a vector-like electroweak doublet, but many results generalize to other models of weakly-interacting dark matter. We re-evaluate the indirect detection constraints on this model and find that, once all annihilation channels are properly taken into account, the most stringent constraints on spin-dependent scattering for dark matter mass 60 GeV < mX < mt are derived from the results of the Super-Kamiokande experiment. Moreover, we establish the model-independent statement that Majorana dark matter whose thermal relic abundance and neutrino signals are both controlled by annihilation via an s-channel Z boson is excluded for 70 GeV < mX < mW. In some models, annihilation to tt* can affect indirect detection, notably by competing with annihilation to gauge boson final states and thereby weakening neutrino signals. However, in the minimal model, this final state is largely negligible, only allowing dark matter with mass a few GeV below the top quark mass to evade exclusion.Comment: 22 pages, 5 figure

Exotic Top Partners and Little Higgs

Little Higgs models often give rise to top partners beyond the minimal ones necessary for the cancellation of quadratic divergences. We review how this occurs and discuss the phenomenology of these exotic states. We emphasize the possible importance of new pseudo-Nambu-Goldstone bosons in top partner decays. Indeed, cascade decays of exotic top partners may be the best way to discover these new bosons. We illustrate these points with a new Little Higgs construction based on an SO(10)/SO(5)^2 coset structure, which fills a gap in the model building literature. These observations motivate new search strategies for top partners at the LHC, including for final states with b-jets and a large multiplicity of electroweak bosons.Comment: 27 pages, 2 figures, 4 tables; v3: JHEP revision -- updated to include discussion of naturalness and section 2.1 expande

Discrimination of form in images corrupted by speckle

The problem investigated is that of a human observer having to distinguish between certain specified geometrical forms corrupted by speckle-an idealization of the problem of a scientist studying a synthetic aperture radar map. Specifically, the cases of two simple alternative forms and of two and four orientations of a simple form have been considered. A theoretical model is developed for the observer's decision process by analogy with optimal receiver theory, and the probability of a correct decision is related to form parameters like size, contrast, and looks. These calculations are verified by psychophysical experiments using computer-simulated pictures

The effect of phase-feeding on the growth performance, carcass characteristics and nitrogen balance of growing and finishing pigs.

peer-reviewedA completely randomised design experiment was conducted to determine if grouphoused grower-finisher pigs (43.9 to 95 kg) show differences in performance and nitrogen utilisation when provided with a single high lysine diet (11 g/kg) or with a mean lysine concentration of 9.5 g/kg, either as a single diet or as a series of two or four diets. Four hundred and forty pigs were assigned to four dietary treatments. The experimental treatments were (total lysine) (1) 11 g lysine/kg from day 0 to slaughter (SHD) (2) 10.5 g/kg lysine from day 0 to day 28 and 8.5 g/kg lysine from day 29 to slaughter (DFD) (3) 9.5 g/kg lysine from day 0 to slaughter (RFD) and (4) 11 g/kg lysine from day 0 to day 14, 10 g/kg lysine from day 14 to day 28, 9.0 g/kg lysine from day 28 to day 42 and 8.0 g/kg lysine from day 42 to slaughter (PFD). The estimated lysine concentration required for treatments RFD, DFD and PFD was 9.5 g/kg for group-housed pigs. All diets were pelleted and formulated to have a net energy concentration of 9.8 MJ/kg. The pigs were group fed in mixed-sex pens using single space feeders (11 pigs/feeder, 6 boars and 5 gilts). Daily feed intake was lower (P < 0.05) in treatment SHD in comparison to RFD and DFD during the overall grower-finisher period (2.08 vs 2.18 and 2.23 kg/day, respectively). Lysine conversion ratio was poorer for pigs on treatment SHD compared with DFD (P < 0.01), RFD (P < 0.01) or PFD (P < 0.001), while food conversion ratio was better for pigs on treatment SHD compared with treatments DFD (P < 0.01) and PFD (P < 0.001) during the grower-finisher period (2.31 vs 2.43 and 2.48 kg/kg, respectively). N intake and excretion were higher (P < 0.001) for pigs offered SHD compared to all other treatments (3.93 vs 3.51, 3.42, 3.40 kg and 2.56 vs 2.14, 2.03, 2.10 kg for SHD vs DFD RFD and PFD for intake and excretion, respectively). N utilisation coefficient was lower for pigs on treatment SHD than pigs on treatments DFD (P < 0.01), RFD (P < 0.001) or PFD (P < 0.01). In conclusion, phase feeding did not result in any benefit to pig performance, N excretion, N utilisation or carcass characteristics when compared with a single diet that was formulated to match the animal’s requirement for lysine (treatment RFD)