Evaluating the Use of Lidar to Discern Snag Characteristics Important for Wildlife

Standing dead trees (known as snags) are historically difficult to map and model using airborne laser scanning (ALS), or lidar. Specific snag characteristics are important for wildlife; for instance, a larger snag with a broken top can serve as a nesting platform for raptors. The objective of this study was to evaluate whether characteristics such as top intactness could be inferred from discrete-return ALS data. We collected structural information for 198 snags in closed-canopy conifer forest plots in Idaho. We selected 13 lidar metrics within 5 m diameter point clouds to serve as predictor variables in random forest (RF) models to classify snags into four groups by size (small (<40 cm diameter) or large (≥40 cm diameter)) and intactness (intact or broken top) across multiple iterations. We conducted these models first with all snags combined, and then ran the same models with only small or large snags. Overall accuracies were highest in RF models with large snags only (77%), but kappa statistics for all models were low (0.29–0.49). ALS data alone were not sufficient to identify top intactness for large snags; future studies combining ALS data with other remotely sensed data to improve classification of snag characteristics important for wildlife is encouraged

Unlocking keystone structures: Opening the door to new uses of airborne and handheld lidar for remote characterization of standing dead trees and nest cavities in closed-canopy conifer forests

In closed-canopy conifer forests, standing dead trees (known as snags) serve as keystone structures, supporting disproportionate amounts of biodiversity. Their reduced woody structure, as well as their decaying wood, make snags different enough from live trees to provide unique habitat features for wildlife. One such feature of snags in northwestern conifer forests¬ is that they are the preferred sites for woodpeckers to excavate nest cavities, which are also considered keystone structures in this system. Woodpecker cavities are essential to multiple species of birds and mammals for nesting and roosting–and this habitat feature makes locating snags all the more valuable. Using remote sensing to map where snags occur across the landscape is of great benefit in multiple ecological contexts but is made difficult due the sparse, cryptic, and variable nature of standing deadwood throughout a forest.This dissertation tests novel methodologies to evaluate whether one type of remote sensing, light detection and ranging (known as lidar), applied at different spatial scales is sensitive enough to discern structural characteristics pertaining to: (1) snags versus live trees; (2) variation among snags; and (3) tree cavity entrance dimensions. I evaluated lidar at the landscape scale for (1) and (2) to explore the capabilities of airborne lidar for snag detection and characterization in conifer stands of the Idaho Panhandle National Forest. I evaluated lidar at the individual tree scale for (3) to determine the accuracy of smartphone lidar in measuring cavity entrance dimensions under controlled conditions. I found airborne lidar to be (1) effective at distinguishing between snags and live trees at the individual tree level using the proportion of open space surrounding each, but (2) airborne lidar was not high enough resolution to reliably characterize multiple snag classes. I found that smartphone lidar (3) was very accurate in measuring at least one dimension of cavity entrance size, enabling discernment among species of cavity excavators.doctoral, Ph.D., Natural Resources -- University of Idaho - College of Graduate Studies, 2022-0

Retinal vascular regeneration

Dysfunction of the retinal vasculature can impact on visual function. In many chorioretinal disorders, impairment of vascular function is a central pathogenic event. Extensive research has investigated mechanisms driving vascular damage when compared to vascular regeneration. Nevertheless, vasoreparative processes have been shown to slow the progression of eye vascular diseases. Here, we review evidence for retinal vascular regeneration in mice and humans. There have been preclinical studies conducted using cell therapy to promote vascular regeneration, including bone marrow-CD34+ progenitor cells, umbilical cord blood-derived endothelial colony-forming cells, and induced pluripotent stem cell-derived endothelial cells. Endogenous retinal vascular regeneration is also modulated by molecular pathways such as Semaphorins, Wnt, and Connexin 43. Additionally, drugs that remove senescent cells, have also been suggested to enhance reparative retinal vascular regeneration. All the scientific evidence discussed in this chapter highlights the importance of understanding vascular regeneration in the context of ischemic eye disease

Retinal vascular regeneration

Dysfunction of the retinal vasculature can impact on visual function. In many chorioretinal disorders, impairment of vascular function is a central pathogenic event. Extensive research has investigated mechanisms driving vascular damage when compared to vascular regeneration. Nevertheless, vasoreparative processes have been shown to slow the progression of eye vascular diseases. Here, we review evidence for retinal vascular regeneration in mice and humans. There have been preclinical studies conducted using cell therapy to promote vascular regeneration, including bone marrow-CD34+ progenitor cells, umbilical cord blood-derived endothelial colony-forming cells, and induced pluripotent stem cell-derived endothelial cells. Endogenous retinal vascular regeneration is also modulated by molecular pathways such as Semaphorins, Wnt, and Connexin 43. Additionally, drugs that remove senescent cells, have also been suggested to enhance reparative retinal vascular regeneration. All the scientific evidence discussed in this chapter highlights the importance of understanding vascular regeneration in the context of ischemic eye disease.<br/

Postoperative continuous positive airway pressure to prevent pneumonia, re-intubation, and death after major abdominal surgery (PRISM): a multicentre, open-label, randomised, phase 3 trial

Background: Respiratory complications are an important cause of postoperative morbidity. We aimed to investigate whether continuous positive airway pressure (CPAP) administered immediately after major abdominal surgery could prevent postoperative morbidity. Methods: PRISM was an open-label, randomised, phase 3 trial done at 70 hospitals across six countries. Patients aged 50 years or older who were undergoing elective major open abdominal surgery were randomly assigned (1:1) to receive CPAP within 4 h of the end of surgery or usual postoperative care. Patients were randomly assigned using a computer-generated minimisation algorithm with inbuilt concealment. The primary outcome was a composite of pneumonia, endotracheal re-intubation, or death within 30 days after randomisation, assessed in the intention-to-treat population. Safety was assessed in all patients who received CPAP. The trial is registered with the ISRCTN registry, ISRCTN56012545. Findings: Between Feb 8, 2016, and Nov 11, 2019, 4806 patients were randomly assigned (2405 to the CPAP group and 2401 to the usual care group), of whom 4793 were included in the primary analysis (2396 in the CPAP group and 2397 in the usual care group). 195 (8\ub71%) of 2396 patients in the CPAP group and 197 (8\ub72%) of 2397 patients in the usual care group met the composite primary outcome (adjusted odds ratio 1\ub701 [95% CI 0\ub781-1\ub724]; p=0\ub795). 200 (8\ub79%) of 2241 patients in the CPAP group had adverse events. The most common adverse events were claustrophobia (78 [3\ub75%] of 2241 patients), oronasal dryness (43 [1\ub79%]), excessive air leak (36 [1\ub76%]), vomiting (26 [1\ub72%]), and pain (24 [1\ub71%]). There were two serious adverse events: one patient had significant hearing loss and one patient had obstruction of their venous catheter caused by a CPAP hood, which resulted in transient haemodynamic instability. Interpretation: In this large clinical effectiveness trial, CPAP did not reduce the incidence of pneumonia, endotracheal re-intubation, or death after major abdominal surgery. Although CPAP has an important role in the treatment of respiratory failure after surgery, routine use of prophylactic post-operative CPAP is not recommended