Pressure-induced reconstructive phase transition in Cd3As2

Cadmium arsenide Cd3As2 hosts massless Dirac electrons in its ambient-conditions tetragonal phase. We report X-ray diffraction and electrical resistivity measurements of Cd3As2 upon cycling pressure beyond the critical pressure of the tetragonal phase and back to ambient conditions. We find that at room temperature the transition between the low- and high-pressure phases results in large microstrain and reduced crystallite size both on rising and falling pressure. This leads to non-reversible electronic properties including self-doping associated with defects and a reduction of the electron mobility by an order of magnitude due to increased scattering. Our study indicates that the structural transformation is sluggish and shows a sizable hysteresis of over 1 GPa. Therefore, we conclude that the transition is first-order reconstructive, with chemical bonds being broken and rearranged in the high-pressure phase. Using the diffraction measurements we demonstrate that annealing at ~200 deg. C greatly improves the crystallinity of the high-pressure phase. We show that its Bragg peaks can be indexed as a primitive orthorhombic lattice with a_HP = 8.68 Å, b_HP = 17.15 Å and c_HP = 18.58 Å. The diffraction study indicates that during the structural transformation a new phase with another primitive orthorhombic structure may be also stabilized by deviatoric stress, providing an additional venue for tuning the unconventional electronic states in Cd3As2

Characteristics of the boreal mixedwood forest associated with subnivean access by the American Marten (Martes americana)

Habitat selection by the American marten (Martes americana ), in studies throughout its range, has been associated with forest types that offer higher structural complexity. Such structure has been proposed to facilitate predator avoidance and access to the subnivean environment for thermoregulation and food procurement. The purpose of my study was to assess fine-scale habitat characteristics at points of subnivean access, and to use these characteristics to evaluate stands designated as reserved marten habitat according to the Forest Management Guidelines for the Provision of Marten Habitat in Ontario . In two study areas near Kapuskasing and near Thunder Bay, Ontario, I used point sampling to measure overhead canopy cover and various attributes of downed wood and dead trees, and plot sampling to describe understory woody vegetation, where 31 subnivean access points had been determined by winter tracking of marten. A case-control design and stepwise logistic regression were used to compare habitat at marten access points to habitat available in adjacent areas, using two or more reference points each 50-100 m from an access point. Overhead canopy cover ( P = 0.003), abundance of coarse woody debris (P = 0.020), and deciduous understory stem density (P =0.030) were positively associated with subnivean access. Total volume of standing dead trees (snags) and coarse woody debris in intermediate stages of decay, identified by loose bark and little to no intact fine branch structure, were negatively associated with subnivean access when estimated as volume within a plot ( P = 0.047). In habitat reserves in the Lakehead Forest, near Thunder Bay, the same characteristics were used in a forward stepwise discriminant function analysis comparing sites of used subnivean access and proximally located control points to stands designated as "good" and "fair" suitable marten habitat within marten cores. The discriminant function analysis was able to distinguish the "good" suitable habitat from the case - control model to a greater degree than the "fair" suitable habitat

Take me back to old Ontario

Gift of Dr. Mary Jane Esplen.Piano vocal [instrumentation]In a far and foreign land [first line]Take me back to old Ontario where the sun does ever shine [first line of chorus]F [key]Andante moderato [tempo]Popular song [form/genre]No publisher's advertisement [note

Take me back to old Ontario

Gift of Dr. Mary Jane Esplen.Piano vocal [instrumentation]In a far and foreign land [first line]Take me back to old Ontario where the sun does ever shine [first line of chorus]F [key]Andante moderato [tempo]Popular song [form/genre]No publisher's advertisement [note