Bridging the gap between academia and practice: Perspectives from two large-scale and niche research projects in Canada.

There is a recognized disconnect in priority and synergy between academic and practitioners in forensic science. In this work, we personally reflect on our experiences in conducting research studies that directly involve academic and practitioner stakeholders. We believe, amongst others, that this "gap" can be mitigated through regular and productive communication. We also emphasize the need to create stronger and national research strategies which identifies the current and pressing needs of enforcement officials in order to bring these needs directly to academia. As part of this, researchers should actively seek to make sure what they study will be relevant within the discipline. Our reflection is geared on direct feedback from an entomological study in large scale sampling of blowflies and workshops in bloodstain pattern analysis using a forensic blood substitute.

Blood drop size in passive dripping from weapons.

Passive dripping, the slow dripping of blood under gravity, is responsible for some bloodstains found at crime scenes, particularly drip trails left by a person moving through the scene. Previous work by other authors has established relationships, under ideal conditions, between the size of the stain, the number of spines and satellite stains, the roughness of the surface, the size of the blood droplet and the height from which it falls. To apply these relationships to infer the height of fall requires independent knowledge of the size of the droplet. This work aims to measure the size of droplets falling from objects representative of hand-held weapons. Pig blood was used, with density, surface tension and viscosity controlled to fall within the normal range for human blood. Distilled water was also tested as a reference. Drips were formed from stainless steel objects with different roughnesses including cylinders of diameter between 10 and 100 mm, and flat plates. Small radius objects including a knife and a wrench were also tested. High speed images of the falling drops were captured. The primary blood drop size ranged from 4.15±0.11 mm up to 6.15±0.15 mm (depending on the object), with the smaller values from sharper objects. The primary drop size correlated only weakly with surface roughness, over the roughness range studied. The number of accompanying droplets increased with the object size, but no significant correlation with surface texture was observed. Dripping of blood produced slightly smaller drops, with more accompanying droplets, than dripping water.