Twinning as an Evolved Age-Dependent Physiological Mechanism: Evidence from Large Brazilian Samples

Tree rings provide an important biological archive for climate history in relation to the physiological mechanism of tree growth. Higher elevation forests including treelines are reliable indicators of climatic changes, and tree growth at most elevational treelines are sensitive to temperature at moist regions, while it is sensitive to moisture in semi-arid regions. However, there has been very less pieces of evidence regarding the age-related growth sensitivity of high mountain tree species. This study identified the key difference on the growth response of younger (<30 years of age) and older (>30 years) Abeis spectabilis trees from treeline ecotone of the Trans-Himalayan region in central Nepal. The adult trees showed a stronger positive correlation with precipitation (moisture) over juveniles giving the evidence of higher demand of water for adult trees, particularly in early growth seasons (March to May). The relationship between tree ring width indices and mean temperature was also different in juveniles and adult individuals, indicating that the juveniles are more sensitive to temperature whereas the adults are more sensitive to moisture availability. It is emphasized that the age-dependent growth response to climate has to be considered while analyzing the growth-climate relationship of high mountain tree populations.

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Effects of Hyperoxia on Lung Utrastructure

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100067121 ◽

1970 ◽

Vol 28 ◽

pp. 26-27

Author(s):

Gladys Harrison

Keyword(s):

Central Nervous System ◽

Nervous System ◽

Light Microscopy ◽

Oxygen Effects ◽

Age Dependent ◽

The Central Nervous System ◽

The Subject ◽

Space Age ◽

Alveolar Septa ◽

Extensive Damage

With the advent of the space age and the need to determine the requirements for a space cabin atmosphere, oxygen effects came into increased importance, even though these effects have been the subject of continuous research for many years. In fact, Priestly initiated oxygen research when in 1775 he published his results of isolating oxygen and described the effects of breathing it on himself and two mice, the only creatures to have had the “privilege” of breathing this “pure air”.Early studies had demonstrated the central nervous system effects at pressures above one atmosphere. Light microscopy revealed extensive damage to the lungs at one atmosphere. These changes which included perivascular and peribronchial edema, focal hemorrhage, rupture of the alveolar septa, and widespread edema, resulted in death of the animal in less than one week. The severity of the symptoms differed between species and was age dependent, with young animals being more resistant.

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Obesity and adiposity: the culprit of dietary protein efficacy

Clinical Science ◽

10.1042/cs20190583 ◽

2020 ◽

Vol 134 (4) ◽

pp. 389-401

Author(s):

Carla El-Mallah ◽

Omar Obeid

Keyword(s):

Food Intake ◽

Behavioural Change ◽

Physiological Mechanism ◽

Short Term ◽

The Past ◽

Body Adiposity ◽

Reduce Sugar ◽

Eye Opening ◽

Potential Strategy ◽

Limitations And Exceptions

Abstract Obesity and increased body adiposity have been alarmingly increasing over the past decades and have been linked to a rise in food intake. Many dietary restrictive approaches aiming at reducing weight have resulted in contradictory results. Additionally, some policies to reduce sugar or fat intake were not able to decrease the surge of obesity. This suggests that food intake is controlled by a physiological mechanism and that any behavioural change only leads to a short-term success. Several hypotheses have been postulated, and many of them have been rejected due to some limitations and exceptions. The present review aims at presenting a new theory behind the regulation of energy intake, therefore providing an eye-opening field for energy balance and a potential strategy for obesity management.

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