Motivic DT-invariants for the one loop quiver with potential

In this paper we compute the motivic Donaldson--Thomas invariants for the quiver with one loop and any potential. As the presence of arbitrary potentials requires the full machinery of \hat(\mu)-equivariant motives, we give a detailed account of them. In particular, we will prove two results for the motivic vanishing cycle which might be of importance not only in Donaldson--Thomas theory.Comment: 30 page

Reliable confidence intervals in quantitative genetics: narrow-sense heritability

Many quantitative genetic statistics are functions of variance components, for which a large number of replicates is needed for precise estimates and reliable measures of uncertainty, on which sound interpretation depends. Moreover, in large experiments the deaths of some individuals can occur, so methods for analysing such data need to be robust to missing values. We show how confidence intervals for narrow-sense heritability can be calculated in a nested full-sib/half-sib breeding design (males crossed with several females) in the presence of missing values. Simulations indicate that the method provides accurate results, and that estimator uncertainty is lowest for sampling designs with many males relative to the number of females per male, and with more females per male than progenies per female. Missing data generally had little influence on estimator accuracy, thus suggesting that the overall number of observations should be increased even if this results in unbalanced data. We also suggest the use of parametrically simulated data for prior investigation of the accuracy of planned experiments. Together with the proposed confidence intervals an informed decision on the optimal sampling design is possible, which allows efficient allocation of resource

Simultaneous multiplane imaging with reverberation multiphoton microscopy

Multiphoton microscopy (MPM) has gained enormous popularity over the years for its capacity to provide high resolution images from deep within scattering samples1. However, MPM is generally based on single-point laser-focus scanning, which is intrinsically slow. While imaging speeds as fast as video rate have become routine for 2D planar imaging, such speeds have so far been unattainable for 3D volumetric imaging without severely compromising microscope performance. We demonstrate here 3D volumetric (multiplane) imaging at the same speed as 2D planar (single plane) imaging, with minimal compromise in performance. Specifically, multiple planes are acquired by near-instantaneous axial scanning while maintaining 3D micron-scale resolution. Our technique, called reverberation MPM, is well adapted for large-scale imaging in scattering media with low repetition-rate lasers, and can be implemented with conventional MPM as a simple add-on.Accepted manuscrip

Genome sequence of a novel alloherpesvirus isolated from glass catfish (Kryptopterus bicirrhis)

The 149,343-bp genome of silurid herpesvirus 1, which was isolated in Thailand from glass catfish, was sequenced. The genome was most closely related to that of ictalurid herpesvirus 2, which infects black bullhead catfish. To our knowledge, this was the first silurid catfish alloherpesvirus genome to be sequenced

Numerical modelling of heat generation in porous planetesimal collisions

An important unanswered question in planetary science is how planetesimals, the ~1–100 km solid precursors to asteroids and planets, were heated in the early Solar System. This thesis quantifies one possible heat source: planetesimal collisions. Recent work has predicted that collision velocities and planetesimal porosities were likely to have been higher than previously thought; this is likely to have significant implications on collision heating. The approach adopted in this research was to numerically model shock heating during planetesimal collisions. Simulations showed that an increase in porosity can significantly increase heating: in a 5 km s-1 collision between equal sized, non-porous planetesimals, no material was heated to the solidus, compared to two thirds of the mass of 50% porous planetesimals. Velocity also strongly influences heating: at 4 km s-1, an eighth of the mass of 50% porous planetesimals was heated to the solidus, compared to the entire mass at 6 km s-1. Further simulations quantified the influence on heating of the impactor-to-target mass ratio, the initial planetesimal temperature and the impact angle. A Monte Carlo model was developed to examine the cumulative heating caused by a population of impactors striking a parent body. In the majority of collisions the impactor was much smaller than the parent body, and only minor heating was possible. However, some larger or faster impactors were capable of causing significant heating without disrupting the parent body; these collisions could have heated up to 10% of the parent body to the solidus. To cause global heating, the collision must have catastrophically disrupted the parent body. The increase in specific internal energy from collisions was compared with the decay of short-lived radionuclides. In the first ~6 Ma, radioactive decay was the most important heat source. After ~10 Ma, the energy caused by collisions was likely to have overtaken radioactive decay as the dominant source

Skills for Success

'Skills for Success': a year 0 programme of guest speakers and workshops designed to support students holistic development as they transition into HE

Validation of a Compact Isokinetic Total Water Content Probe for Wind Tunnel Characterization at NASA Glenn Icing Research Tunnel and at NRC Ice Crystal Tunnel

A new compact isokinetic probe to measure total water content in a wind tunnel environment has been developed. The probe has been previously tested under altitude conditions. This paper presents a comprehensive validation of the probe under a range of liquid water conditions at sea level in the NASA Glenn Icing Research Tunnel and with ice crystals at sea level at the NRC wind tunnel. The compact isokinetic probe is compared to tunnel calibrations and other probes