A method to map within-tree distribution of fibre properties using SilviScan-3 data

2009 ◽  
Vol 85 (3) ◽  
pp. 409-414 ◽  
Author(s):  
Maurice Defo ◽  
Andrew Goodison ◽  
Nelson Uy
Keyword(s):  
Wood Properties ◽  
Douglas Fir ◽  
Stem Volume ◽  
Preliminary Evaluation ◽  
Fibre Properties ◽  
Tree Distribution ◽  
Triangular Elements ◽  
Armillaria Root Disease ◽  
The Impact ◽  
Tree Distributions

This paper shows how SilviScan-3 data can be used to map the within-tree distributions of wood properties, and to compute relevant statistics useful for tree-to-tree comparisons. An algorithm named EvaluTreeMap was developed for this purpose, based on subdividing the stem into triangular elements. It was validated using a stem of conical shape with properties exhibiting conical symmetry. To illustrate some applications of the program, it was used for the preliminary evaluation of the impact of Armillaria root disease on the fibre coarseness of Douglas-fir trees. Key words: SilviScan-3, fibre properties, within-tree variations, EvaluTreeMap, meshing, mapping, stem volume, tree's mean properties and standard deviation, Armillaria ostoyae, fibre coarseness, Douglas-fir

Late-rotation nitrogen fertilization of Douglas-fir: growth response and fibre properties

2017 ◽  
Vol 47 (1) ◽  
pp. 134-138 ◽  
Author(s):  
Cosmin N. Filipescu ◽  
John A. (Tony) Trofymow ◽  
Ross S. Koppenaal
Keyword(s):  
Nitrogen Fertilization ◽  
Growth Response ◽  
Negative Impact ◽  
Management Practice ◽  
Wood Quality ◽  
Fibre Length ◽  
Douglas Fir ◽  
Stem Volume ◽  
Fibre Properties ◽  
The Impact

Late-rotation fertilization of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) 5 to 10 years before harvesting is a common management practice in British Columbia and the US Pacific Northwest. Despite widespread operational application, knowledge on the impact of late-rotation fertilization on forests, especially fibre properties, is lacking. In this study, we evaluate the growth response and fibre properties following nitrogen fertilization in a productive second-growth coastal Douglas-fir site at age 57 years. Destructive sampling of dominant and co-dominant trees in fertilized and control plots 5 years after fertilization indicated significant gain in stem volume (30%–40%) that was uniformly distributed along the stem. There were no discernible effects on wood quality at the log level in terms of resonance acoustic velocity. However, fibre properties within breast height tree rings indicated significant reductions of ring wood density (by 8%), earlywood density (17%), latewood percentage (10%), and modulus of elasticity (8%). Tracheid dimensions declined in earlywood (reduction of wall thickness by 15%), latewood (radial diameter by 8%), and fibre length (by 6%). Results indicate that late-rotation nitrogen fertilization of Douglas-fir may lead to a significant growth response with only minimal reduction of fibre properties. It is possible that the negative impact on fibre properties could become more significant for repeated applications or higher rates of nitrogen fertilization.

Effect of Armillaria root disease on quality and value of green Douglas-fir lumber

2010 ◽  
Vol 86 (2) ◽  
pp. 263-266 ◽  
Author(s):  
M G Cruickshank
Keyword(s):  
Tree Species ◽  
Wood Quality ◽  
Douglas Fir ◽  
Root Disease ◽  
Tree Level ◽  
Stem Taper ◽  
Negative Effect ◽  
Key Words Disease ◽  
Armillaria Root Disease ◽  
The Impact

For a few tree species, scattered accounts of impact caused by root disease exist in the literature mainly at the tree level. No product quality impacts have ever been measured or properly costed. To provide some information on value impacts, green rough-sawn Douglas-fir lumber was cut from trees with and without Armillaria root disease. This produced 80 boards from six trees in two planted stands. Fewer boards came from living diseased trees compared to healthy trees of similar diameter (1.3 m) at both sites, suggesting that disease may affect stem taper or form. Lumber from diseased trees was affected most often by warp and for healthy trees by knots, but warp affected value the most. Disease appears to have at best no effect, and at worst, a negative effect on lumber value but is not likely to increase value. This is the first report of the impact of a root disease on lumber quality and value, but further work would be required to properly assess this. Key words: disease, Armillaria root disease, conifer, Douglas-fir, wood quality, lumber warping, lumber value, lumber grading

Impact of stem lean on estimation of Douglas-fir (Pseudotsuga menziesii) diameter and volume using mobile lidar scans

2021 ◽  
Author(s):  
Cory Glenn Garms ◽  
Bogdan Strimbu
Keyword(s):  
Pacific Northwest ◽  
Pseudotsuga Menziesii ◽  
Point Clouds ◽  
Douglas Fir ◽  
Stem Volume ◽  
Horizontal Distance ◽  
The Pacific ◽  
Commercial Species ◽  
The Impact ◽  
Volume Models

The value of Douglas-fir (Pseudotsuga menziesii), which is the predominant commercial species in the Pacific Northwest, depends on tree verticality; trees with same dimensions can differ substantially in value due to lean. The objective of this study was to assess the impact of tree leaning on estimation of stem dimensions using high density terrestrial mobile lidar point clouds. We estimated lean with two metrics: the horizontal distance between stem centers at 1.3m and 18m, and the mean of seven successive lean angles along the tree bole (at 1, 3, 5, 7, 10, 12, and 15m). For modeling, we used four existing taper equations and three existing volume equations. For trees leaning >2º, we enhanced the existing volume models by including lean as a predictor. Because lean estimates depend on the distribution and number of points describing the stem, we found that including the distance from scanner to tree improved the computed volume. When DBH was replaced with diameter at heights between 7 - 10m, the volume models for leaning trees improved significantly, whereas the vertical trees had favorable results with heights between 5-15m. Our study suggests the inclusion of lean magnitude improves estimates of stem volume when lean is >2°.

scholarly journals An Evaluation Methodology for Interactive Reinforcement Learning with Simulated Users

Biomimetics ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 13
Author(s):  
Adam Bignold ◽  
Francisco Cruz ◽  
Richard Dazeley ◽  
Peter Vamplew ◽  
Cameron Foale
Keyword(s):  
Reinforcement Learning ◽  
Information Source ◽  
Human Interaction ◽  
Evaluation Methodology ◽  
External Information ◽  
Preliminary Evaluation ◽  
Learning Agents ◽  
Learning Agent ◽  
Knowledge Bias ◽  
The Impact

Interactive reinforcement learning methods utilise an external information source to evaluate decisions and accelerate learning. Previous work has shown that human advice could significantly improve learning agents’ performance. When evaluating reinforcement learning algorithms, it is common to repeat experiments as parameters are altered or to gain a sufficient sample size. In this regard, to require human interaction every time an experiment is restarted is undesirable, particularly when the expense in doing so can be considerable. Additionally, reusing the same people for the experiment introduces bias, as they will learn the behaviour of the agent and the dynamics of the environment. This paper presents a methodology for evaluating interactive reinforcement learning agents by employing simulated users. Simulated users allow human knowledge, bias, and interaction to be simulated. The use of simulated users allows the development and testing of reinforcement learning agents, and can provide indicative results of agent performance under defined human constraints. While simulated users are no replacement for actual humans, they do offer an affordable and fast alternative for evaluative assisted agents. We introduce a method for performing a preliminary evaluation utilising simulated users to show how performance changes depending on the type of user assisting the agent. Moreover, we describe how human interaction may be simulated, and present an experiment illustrating the applicability of simulating users in evaluating agent performance when assisted by different types of trainers. Experimental results show that the use of this methodology allows for greater insight into the performance of interactive reinforcement learning agents when advised by different users. The use of simulated users with varying characteristics allows for evaluation of the impact of those characteristics on the behaviour of the learning agent.

scholarly journals A Whole Virion Vaccine for COVID-19 Produced via a Novel Inactivation Method and Preliminary Demonstration of Efficacy in an Animal Challenge Model

Vaccines ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 340
Author(s):  
Izabela K Ragan ◽  
Lindsay M Hartson ◽  
Taru S Dutt ◽  
Andres Obregon-Henao ◽  
Rachel M Maison ◽  
...  
Keyword(s):  
Vaccine Candidate ◽  
Rapid Development ◽  
Neutralizing Antibody ◽  
Emerging Diseases ◽  
Effective Vaccine ◽  
Preliminary Evaluation ◽  
Sequencing Data ◽  
Post Challenge ◽  
Vaccine Candidates ◽  
The Impact

The COVID-19 pandemic has generated intense interest in the rapid development and evaluation of vaccine candidates for this disease and other emerging diseases. Several novel methods for preparing vaccine candidates are currently undergoing clinical evaluation in response to the urgent need to prevent the spread of COVID-19. In many cases, these methods rely on new approaches for vaccine production and immune stimulation. We report on the use of a novel method (SolaVAX) for production of an inactivated vaccine candidate and the testing of that candidate in a hamster animal model for its ability to prevent infection upon challenge with SARS-CoV-2 virus. The studies employed in this work included an evaluation of the levels of neutralizing antibody produced post-vaccination, levels of specific antibody sub-types to RBD and spike protein that were generated, evaluation of viral shedding post-challenge, flow cytometric and single cell sequencing data on cellular fractions and histopathological evaluation of tissues post-challenge. The results from this preliminary evaluation provide insight into the immunological responses occurring as a result of vaccination with the proposed vaccine candidate and the impact that adjuvant formulations, specifically developed to promote Th1 type immune responses, have on vaccine efficacy and protection against infection following challenge with live SARS-CoV-2. This data may have utility in the development of effective vaccine candidates broadly. Furthermore, the results of this preliminary evaluation suggest that preparation of a whole virion vaccine for COVID-19 using this specific photochemical method may have potential utility in the preparation of one such vaccine candidate.

scholarly journals Optimal profile for concave slopes under static and seismic conditions

2016 ◽  
Vol 53 (9) ◽  
pp. 1522-1532 ◽  
Author(s):  
Farshid Vahedifard ◽  
Shahriar Shahrokhabadi ◽  
Dov Leshchinsky
Keyword(s):  
Limit Equilibrium ◽  
Stable Configuration ◽  
Preliminary Evaluation ◽  
Construction Technology ◽  
Stability Of Slopes ◽  
Optimal Profile ◽  
Stabilized Soil ◽  
The Stability ◽  
Comparison Of The Results ◽  
The Impact

This study presents a methodology to determine the stability and optimal profile for slopes with concave cross section under static and seismic conditions. Concave profiles are observed in some natural slopes suggesting that such geometry is a more stable configuration. In this study, the profile of a concave slope was idealized by a circular arc defined by a single variable, the mid-chord offset (MCO). The proposed concave profile formulation was incorporated into a limit equilibrium–based log spiral slope stability method. Stability charts are presented to show the stability number, MCO, and mode of failure for homogeneous slopes corresponding to the most stable configuration under static and pseudostatic conditions. It is shown that concave profiles can significantly improve the stability of slopes. Under seismic conditions, the impact of concavity is most pronounced. Good agreement was demonstrated upon comparison of the results from the proposed method against those attended from a rigorous upper bound limit analysis. The proposed methodology, along with recent advances in construction technology, can be employed to use concave profiles in trenches, open mine excavations, earth retaining systems, and naturally cemented and stabilized soil slopes. The results presented provide a useful tool for preliminary evaluation for adopting such concave profiles in practice.

Twin Pregnancies Complicated by a Single Malformed Fetus: Chorionicity, Outcome and Management

2010 ◽  
Vol 13 (5) ◽  
pp. 501-507 ◽  
Author(s):  
Ali Gedikbasi ◽  
Alpaslan Akyol ◽  
Gokhan Yildirim ◽  
Ali Ekiz ◽  
Ahmet Gul ◽  
...  
Keyword(s):  
Gestational Age ◽  
Statistical Significance ◽  
Expectant Management ◽  
Control Group ◽  
Study Group ◽  
Preliminary Evaluation ◽  
Gestational Age At Birth ◽  
The Impact ◽  
Twin Pregnancies ◽  
Age At Birth

The objective of this study was to evaluate the impact of one abnormal fetus in a twin pregnancy, to compare impact of chorionicity and clinical outcome of intervention and expectant management. Thirty-seven dichorionic (DC) twins and 18 monochorionic (MC) twins complicated with one malformed fetus were evaluated for gestational age, birthweight and perinatal outcome. Six hundred and forty-two twin pregnancies were evaluated in the database. The control groups consisted of 429 DC and 86 MC twins without anomalous fetus. Mean birthweight and gestational age at birth for DC control group were (n= 429; 2137g and 34.71 weeks), DC study group,n= 37; 2117g (p= .338) and 33.97 weeks (p= .311), and DC study group with major malformations,n= 30; 2019g (p= .289) and 33.3 weeks (p= .01), and showed only significance for gestational age. There was no statistical significance between MC control group,n= 86; 2097g and 34.93 weeks, and MC study group,n= 18; 2237g (p= .338), and 34.42 weeks (p= .502). Because of limited data, the preliminary evaluation for expectant management and intervention, and survival of at least one normal fetus showed no impact. We conclude that, although, all DC twin pregnancies have a risk for preterm delivery, DC twins complicated with major malformation of one twin, have a lower mean gestational age at birth. Preliminary results for intervention does not improve fetal outcome for DC and MC twins and needs further evaluation with greater studies of impact or review.

Assessing the impact of N-fertilization on biochemical composition and biomass of a Douglas-fir canopy—A remote sensing approach

2012 ◽  
Vol 153 ◽  
pp. 124-133 ◽  
Author(s):  
Thomas Hilker ◽  
Lucie Lepine ◽  
Nicholas C. Coops ◽  
Rachhpal S. Jassal ◽  
T. Andrew Black ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Biochemical Composition ◽  
N Fertilization ◽  
Douglas Fir ◽  
The Impact

scholarly journals Surgeons' Experience of Learning Psychological Skills: A Preliminary Evaluation of a Psychological Skills Training Course

2009 ◽  
Vol 91 (4) ◽  
pp. 321-325 ◽  
Author(s):  
Victoria Mason ◽  
Selina Balloo ◽  
Dominic Upton ◽  
Kamal Heer ◽  
Phil Higton ◽  
...  
Keyword(s):  
Human Factors ◽  
Focus Groups ◽  
Skills Training ◽  
Preliminary Evaluation ◽  
Psychological Skills ◽  
Surgical Performance ◽  
Psychological Skills Training ◽  
Before And After ◽  
Theory Practice Gap ◽  
The Impact

INTRODUCTION A range of human factors have been shown to impact on surgical performance although little is known about the impact of training on the views of surgeons towards these factors or how receptive surgeons are to such training. SUBJECTS AND METHODS This was an observational pilot study using a short questionnaire designed to elicit views of surgeons towards a range of human factors prior to, and immediately following, a course designed to address human factors in surgical performance. Focus groups were also conducted before and immediately after the course to elicit views. RESULTS Of all the human factors assessed, decision-making was rated on a visual analogue scale as having the biggest impact on performance both before and after the course. In general, views of human factors changed following the course, most notably an increase in the extent to which work stress, interpersonal difficulties and personality were believed to affect performance. Three themes emerged from the focus groups: (i) personal professional development; (ii) the relationship between trainer and trainee; and (iii) the changing perspective. CONCLUSIONS Surgeons from a range of specialties are receptive to training on the impact of human factors on performance and this study has shown that views may change following a course designed to address this. Further training to address the theory–practice gap is warranted in addition to an evaluation of its effectiveness.

Mechanical Behavior of Heat Activated Film Adhesives

2021 ◽  
Author(s):  
Prabhat Janamanchi ◽  
Abhijit Dasgupta ◽  
Narendra Singh
Keyword(s):  
Mechanical Behavior ◽  
Thermal Exposure ◽  
Melting Transition ◽  
Preliminary Evaluation ◽  
Curing Conditions ◽  
Structural Applications ◽  
History Of ◽  
Favorable Conditions ◽  
The Impact ◽  
Curing Age

Abstract Heat activated film (HAF) adhesives enable the bonding of materials that are difficult to bond with conventional adhesives where one of the substrates is flexible. Although they are traditionally found in the context of industrial and structural applications, they are increasingly finding use in in electronic products. This paper provides a preliminary evaluation of the mechanical behavior of HAFs. Two commercial polyurethane HAF formulations (designated as HAF-II and HAF-III, for the purpose of this paper) were evaluated to assess the dependence of the mechanical properties on phase transitions and on the thermal exposure history of the material. Both factors were found to play a significant role in determining the overall usability of the materials. The melting transition occurs under 50°C for both materials, after which their stiffness drops significantly. Among the two, HAF-III is preferable as it undergoes a delayed melting transition, effectively extending the usable operating temperature range. As with any adhesive, there are several other factors that can influence the performance of adhesives such as post-curing age, storage, and curing conditions to name a few. The impact of these factors on the material’s strength is also discussed in brief and a recommendation for favorable conditions is provided.

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