The role of Douglas-fir stem sapwood and heartwood in the mechanical and physiological support of crowns and development of stem form

1981 ◽  
Vol 11 (3) ◽  
pp. 459-464 ◽  
Author(s):  
James N. Long ◽  
Frederick W. Smith ◽  
David R. M. Scott
Keyword(s):  
Douglas Fir ◽  
Mechanical Support ◽  
Principal Function ◽  
Stem Form ◽  
Cross Sectional ◽  
Sapwood Area ◽  
Large Trees ◽  
Uniform Resistance ◽  
Form Development

The mechanical and physiological support of a tree's crown is the principal function of its bole. A simple model for Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) of different crown classes explains much of the observed differences in stem form development. Sapwood cross-sectional area at any height on the bole of the tree was found to be related linearly to the amount of foliage above that point; however, in large trees the sapwood area needed to supply transpiring foliage with water is insufficient to provide mechanical support. The combination of sapwood and heartwood was found to provide the stem form that would be expected to ensure uniform resistance to bending by the wind.

Syllepsis in Larixlaricina: association of sylleptic branching with cross-sectional stem growth and stem form of saplings

1987 ◽  
Vol 17 (12) ◽  
pp. 1609-1619 ◽  
Author(s):  
W. D. McCurdy ◽  
G. R. Powell
Keyword(s):  
Growth Increment ◽  
Stem Growth ◽  
Main Stem ◽  
Stem Form ◽  
Cross Sectional ◽  
Long Shoots ◽  
Plus Tree ◽  
Stem Development ◽  
Lateral Branches

The effect of sylleptic branching on past stem growth of 8-year-old Larixlaricina (Du Roi) K. Koch saplings was investigated in relation to the lengths of long shoots borne on sylleptically and proleptically originated lateral branches over a 4-year period. Over time, the sylleptic crown component accounted for increasing proportions of the total crowns of saplings exhibiting syllepsis. The total length of all long shoots in the crown increased linearly from lightly to heavily sylleptic saplings. However, groups of branches of sylleptic origin declined in average shoot vigour more rapidly than did groups of branches of proleptic origin in the same height-growth increment. Annual wood ring production and total stem cross-sectional areas at various positions along the main stem were positively correlated with the proleptic, sylleptic, and total branching components occurring above those positions. Wood production along the stem was greater, more uniform and the resultant stem more conical in heavily sylleptic saplings than in lightly sylleptic saplings. The role of syllepsis in crown and main stem development was discussed in relation to plus-tree selection for tree improvement purposes.

Thinning and nitrogen fertilization effects on sapwood development and relationships of foliage quantity to sapwood area and basal area in Douglas-fir

1983 ◽  
Vol 13 (3) ◽  
pp. 384-389 ◽  
Author(s):  
H. Brix ◽  
A. K. Mitchell
Keyword(s):  
Nitrogen Fertilization ◽  
Basal Area ◽  
Douglas Fir ◽  
Annual Rings ◽  
Cross Sectional ◽  
Sapwood Area ◽  
Breast Height ◽  
Linear Relationships ◽  
Regression Slopes ◽  
Fertilization Effects

A 24-year-old Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stand was treated with various levels and combinations of nitrogen fertilization and thinning. Over a period of 5–9 years after treatments, trees were sampled to determine effects on foliage quantity and sapwood characteristics at different stem heights together with their relationships. Sapwood width remained relatively constant up the stem where heartwood was present, but the number of annual rings it contained decreased with height. The sapwood width at breast height (bh) increased with stem diameter; treatments had little effect on percent sapwood at bh. The ratio of foliage mass to sapwood cross-sectional area changed for different portions of the crown and was lower when based on sapwood area at bh than at base of live crown. Significant linear relationships of foliage mass and area to sapwood area at bh were found, but relationships of foliage to basal area (bh) were just as close for all treatments; treatments significantly affected these relationships with control trees having the lowest regression slopes.

Genetic variation in tree structure and its relation to size in Douglas-fir. II. Crown form, branch characters, and foliage characters

1994 ◽  
Vol 24 (6) ◽  
pp. 1236-1247 ◽  
Author(s):  
J.B. St. Clair
Keyword(s):  
Genetic Variation ◽  
Leaf Area ◽  
Branch Length ◽  
Douglas Fir ◽  
Projection Area ◽  
Cross Sectional ◽  
Needle Size ◽  
Stem Size ◽  
Large Trees ◽  
Crown Projection Area

Genetic variation and covariation among traits of tree size and structure were assessed in an 18-year-old Douglas-fir (Pseudotsugamenziesii var. menziesii (Mirb.) Franco) genetic test in the Coast Range of Oregon. Considerable genetic variation was found for relative crown width; stem increment per crown projection area; leaf area and branch weight relative to crown size; branch diameter and length adjusted for stem size; branch stoutness; cross-sectional area of branches per crown length; and needle size. Little genetic variation was found for branch numbers per whorl, branch angle, and specific leaf area. At both the phenotypic and genetic level, large trees growing well relative to growing space had tall, narrow crowns, high leaf areas per crown projection area or branch length, greater partitioning to leaves versus branches, and stouter branches. Thus, large, efficient trees were those that invested more in the photosynthetic machinery of leaf area and the branch biomass necessary to support that leaf area, but distributed that leaf area over a greater vertical distance. Unfortunately, these traits also were associated with increased branchiness, and selection for these traits would be accompanied by reductions in harvest index and wood quality.

Psychological Resilience Provides No Independent Protection From Suicidal Risk

Crisis ◽  
2016 ◽  
Vol 37 (2) ◽  
pp. 130-139 ◽  
Author(s):  
Danica W. Y. Liu ◽  
A. Kate Fairweather-Schmidt ◽  
Richard Burns ◽  
Rachel M. Roberts ◽  
Kaarin J. Anstey
Keyword(s):  
Risk Factors ◽  
Well Being ◽  
Current Status ◽  
Psychological Resilience ◽  
Cross Sectional ◽  
Life Project ◽  
Resilience Factors ◽  
First Time

Abstract. Background: Little is known about the role of resilience in the likelihood of suicidal ideation (SI) over time. Aims: We examined the association between resilience and SI in a young-adult cohort over 4 years. Our objectives were to determine whether resilience was associated with SI at follow-up or, conversely, whether SI was associated with lowered resilience at follow-up. Method: Participants were selected from the Personality and Total Health (PATH) Through Life Project from Canberra and Queanbeyan, Australia, aged 28–32 years at the first time point and 32–36 at the second. Multinomial, linear, and binary regression analyses explored the association between resilience and SI over two time points. Models were adjusted for suicidality risk factors. Results: While unadjusted analyses identified associations between resilience and SI, these effects were fully explained by the inclusion of other suicidality risk factors. Conclusion: Despite strong cross-sectional associations, resilience and SI appear to be unrelated in a longitudinal context, once risk/resilience factors are controlled for. As independent indicators of psychological well-being, suicidality and resilience are essential if current status is to be captured. However, the addition of other factors (e.g., support, mastery) makes this association tenuous. Consequently, resilience per se may not be protective of SI.

Testing the Strain Theory of Suicide – The Moderating Role of Social Support

Crisis ◽  
2020 ◽  
Vol 41 (2) ◽  
pp. 82-88 ◽  
Author(s):  
Bob Lew ◽  
Ksenia Chistopolskaya ◽  
Yanzheng Liu ◽  
Mansor Abu Talib ◽  
Olga Mitina ◽  
...  
Keyword(s):  
Social Support ◽  
Suicidal Behavior ◽  
Online Survey ◽  
Perceived Social Support ◽  
Strain Theory ◽  
Cross Sectional Survey ◽  
Cross Sectional ◽  
Psychological Strains ◽  
Moderating Role

Abstract. Background: According to the strain theory of suicide, strains, resulting from conflicting and competing pressures in an individual's life, are hypothesized to precede suicide. But social support is an important factor that can mitigate strains and lessen their input in suicidal behavior. Aims: This study was designed to assess the moderating role of social support in the relation between strain and suicidality. Methods: A sample of 1,051 employees were recruited in Beijing, the capital of China, through an online survey. Moderation analysis was performed using SPSS PROCESS Macro. Social support was measured with the Multidimensional Scale of Perceived Social Support, and strains were assessed with the Psychological Strains Scale. Results: Psychological strains are a good predictor of suicidality, and social support, a basic need for each human being, moderates and decreases the effects of psychological strains on suicidality. Limitations: The cross-sectional survey limited the extent to which conclusions about causal relationships can be drawn. Furthermore, the results may not be generalized to the whole of China because of its diversity. Conclusion: Social support has a tendency to mitigate the effects of psychological strains on suicidality.

Role of Sildenafil in the Treatment of Persistent Pulmonary Hypertension of Newborn (PPHN) - Should it Be Withdrawn from Market of Bangladesh due to Threat of being Misuses

2020 ◽  
Vol 35 (2) ◽  
pp. 100-104
Author(s):  
Maksudur Rahman ◽  
Mohammad Abdullah Al Mamun ◽  
MAK Azad Chowdhury ◽  
Abu Sayeed Munsi
Keyword(s):  
Intensive Care Unit ◽  
Intensive Care ◽  
Neonatal Intensive Care ◽  
Cross Sectional Study ◽  
Sectional Study ◽  
Cardiac Intensive Care Unit ◽  
Cross Sectional ◽  
Cardiac Intensive Care ◽  
Hospital Protocol

Background: Recently it has been apprehended that sildenafil, a drug which has been successfully using in the treatment of PPHN and erectile dysfunction in adult, is going to be withdrawn from the market of Bangladesh due to threat of its misuses. Objective: The aim of this study was to see the extent of uses of sildenafil in the treatment of PPHN and importance of availability of this drugs in the market inspite of its probable misuses. Methods: This cross sectional study was conducted in neonatal intensive care unit (NICU), special baby care unit (SCABU) and cardiac intensive care unit (CICU) of Dhaka Shishu (Children) Hospital from June, 2017 to May 2018. Neonates with PPHN were enrolled in the study. All cases were treated with oral sildenefil for PPHN along with others management according to hospital protocol. Data along with other parameters were collected and analyzed. Results: Total 320 patients with suspected PPHN were admitted during the study period. Among them 92 (29%) cases had PPHN. Male were 49(53 %) cases and female were 43(47%) cases. Mean age at hospital admission was 29.7±13.4 hours. Based on echocardiography,13(14%) cases had mild, 38 (41%) cases moderate and 41(45%) cases severe PPHN. Mean duration of sildenafil therapy was 11.9±7.1 days. Improved from PPHN were 83 (90%) cases. Mortality was 10% (9). Conclusion: In this study it was found that the incidence of PPHN is 29% among the suspected newborns. Sildenafil is successfull in improving the oxygenation of PPHN and to decrease the mortality of neonates. DS (Child) H J 2019; 35(2) : 100-104

Role of Fibrinolytic Therapy in Empyema Thoracis – A Hospital Based one year Cross Sectional Study

2012 ◽  
Vol 2 (2) ◽  
pp. 345-350
Author(s):  
Dr. Girish.L Dandagi ◽  
◽  
Venkat kalyana kumar. P ◽  
Dr. Dr.Isaac Mathew ◽  
Dr. Dr.G S Gaude Dr. Dr.G S Gaude
Keyword(s):  
Cross Sectional Study ◽  
Fibrinolytic Therapy ◽  
Empyema Thoracis ◽  
Sectional Study ◽  
Cross Sectional ◽  
One Year

Sleep Reactivity and Psychological Health in Normal Sleepers: the moderating role of stress

2018 ◽  
Author(s):  
Jason G. Ellis ◽  
Sarah Allen ◽  
Michael Perlis ◽  
Michael Grandner ◽  
Maria Gardani ◽  
...  
Keyword(s):  
Life Events ◽  
Psychological Health ◽  
Public Health Campaign ◽  
Health Campaign ◽  
Cross Sectional Survey ◽  
Cross Sectional ◽  
Dysfunctional Cognitions ◽  
The Relationship ◽  
Moderating Role

The aim of the present study was to determine whether normal sleepers with vulnerability to insomnia, via high sleep reactivity, demonstrate more sleep-related dysfunctional cognitions and behaviours and poorer psychological health compared to those who are not vulnerable. Further, the influence of stress on the relationship between sleep reactivity and psychological health was also examined. A cross-sectional survey of 737 young adult ‘normal’ sleepers from the general population was undertaken. Results indicated normal sleepers vulnerable to insomnia demonstrated more sleep-related dysfunctional cognitions and behaviours as well as poorer psychological health compared to those not vulnerable. Furthermore, the relationship between sleep reactivity and psychological health was moderated by perceived stress over the previous month and life events over the previous year. Therefore, identifying and supporting those who are vulnerable to insomnia may be a fruitful avenue for preventative public health campaign to mitigate both insomnia and poor psychological health.

Alcohol use in daily life: Examining the role of trait and state impulsivity facets

2020 ◽  
Author(s):  
Sarah A Griffin ◽  
Timothy J Trull
Keyword(s):  
Alcohol Use ◽  
Sensation Seeking ◽  
Daily Life ◽  
Drinking Behavior ◽  
Cross Sectional ◽  
Trait Level ◽  
Trait Impulsivity ◽  
Drinking Behaviors ◽  
Ecological Momentary

Objectives: Using Ecological Momentary Assessment methods (EMA) we aimed to investigate the influence of trait and state (momentary) impulsivity on alcohol use behaviors in daily life. Facets of the UPPS trait model of impulsivity (Whiteside and Lynam, 2001) have been found to differentially relate to alcohol-related outcomes and behaviors in cross-sectional and longitudinal studies. The present work expands on this by assessing UPPS facets in daily life and examining the contributions of trait and state impulsivity facets to daily life drinking behavior. Methods: 49 participants were prompted at least six times per day for 21 days. A total of 4,548 collected EMA reports were included in analyses. Multi-level models were computed predicting daily life alcohol use behaviors from state and trait impulsivity facets and relevant covariates. Results: Individual facets of momentary impulsivity differentially related to alcohol outcomes, such that (lack of) premeditation and, to a lesser extent, sensation seeking showed unique patterns of association with drinking and drinking quantity. Only trait levels of (lack of) premeditation were related to drinking behavior in daily life; no other trait UPPS scale significantly related to alcohol use. Conclusions: These results highlight state difficulties with premeditation as particularly relevant to drinking behavior in daily life. Our results also support the incremental validity of state impulsivity facets over trait level measures in relation to drinking behavior in daily life. These findings offer important insight into the phenomenology of daily-life alcohol use and highlight possible avenues for intervention and prevention efforts. Public Health Statement: Momentary fluctuations in premeditation predict alcohol use in daily life. Treatments targeting planning or forethought in relation to alcohol use may interrupt this process contributing to daily life drinking behaviors.

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