scholarly journals Phenotypic selection on growth rhythm in whitebark pine under climatic conditions warmer than seed origins

2018 ◽  
Vol 31 (9) ◽  
pp. 1284-1299 ◽  
Author(s):  
Marcus V. Warwell ◽  
Ruth G. Shaw

2009 ◽  
Vol 96 (5) ◽  
pp. 1050-1054 ◽  
Author(s):  
Roberto Garcia ◽  
Adam M. Siepielski ◽  
Craig W. Benkman


2007 ◽  
Vol 274 (1620) ◽  
pp. 1799-1805 ◽  
Author(s):  
Adam M Siepielski ◽  
Craig W Benkman

The importance of infrequent events for both adaptive evolution and the evolution of species interactions is largely unknown. We investigated how the infrequent production of large seed crops (masting) of a bird-dispersed tree (whitebark pine, Pinus albicaulis ) influenced phenotypic selection exerted by its primary avian seed predator–disperser, the Clark's nutcracker ( Nucifraga columbiana ). Selection was not evident during common years of low seed abundance, whereas it was replicated among areas and favoured traits facilitating seed dispersal during infrequent years of high seed abundance. Since nutcrackers act mostly as seed predators during small seed crops but as seed dispersers during the largest seed crops, trees experienced strong selection from nutcrackers only during infrequent years when the interaction was most strongly mutualistic. Infrequent events can thus be essential to both adaptive evolution and the evolutionary dynamics of species interactions.



IAWA Journal ◽  
2013 ◽  
Vol 34 (4) ◽  
pp. 498-509 ◽  
Author(s):  
Monique S. Costa ◽  
Thaís J. de Vasconcellos ◽  
Claudia F. Barros ◽  
Cátia H. Callado

This study is aimed to understand responses in growth rhythm to different climatic conditions of the widespread deciduous species Cedrela odorata. Our own research was conducted in Nova Iguaçu. Rio de Janeiro State, Brazil) and compared with literature data from Aripuanã. Mato Grosso State, Brazil), Manaus. Amazonas State, Brazil) and Barinas. Barinas State, Venezuela). Growth periodicity was evaluated through leaf phenological behavior and radial growth. In Nova Iguaçu, leaf phenology was monitored monthly and radial growth was evaluated by cambial histological analysis of samples collected in wet and dry seasons. In the other sites, the authors evaluated the growth rhythm by dendrometer bands. Growth always occurs in the wet season, even when there is no water deficit during the dry season. Thus, the species is considered conservative concerning the maintenance of growth seasonality. Nevertheless, C. odorata was able to change its growth period, following local seasonality of its different growth sites. Therefore we suggest caution when performing climate analysis from a chronology using trees that grow in different periods of the year.



2010 ◽  
Vol 67 (5) ◽  
pp. 531-539 ◽  
Author(s):  
Lilian Elgalise Techio Pereira ◽  
Adenilson José Paiva ◽  
Sila Carneiro da Silva ◽  
Fábio Olegário Caminha ◽  
Vitor Del'Álamo Guarda ◽  
...  

Acceleration of the growth rhythm of plants using nitrogen fertiliser alters the rates of physiological processes like growth and senescence and may cause significant changes in sward structure, interfering with plant and animal responses. The objective of this experiment was to evaluate sward structure of marandu palisadegrass (Brachiaria brizantha) maintained at 30 cm under continuous stocking and subjected to contrasting rhythms of growth from January 2007 to April 2008. These were generated using or not nitrogen fertiliser, and comprised four experimental treatments as follows: control (non-fertilised), 150, 300 and 450 kg ha-1 of N. Acceleration of the growth rhythm of plants was associated with increases in leaf and stem bulk density, and resulted in larger LAI and total bulk density on swards subjected to faster (fertilised with 300 and 450 kg ha-1 of N) than those subjected to slower rhythms of growth (non-fertilised or fertilised with 150 kg ha-1 of N). Variations in dead material bulk density were associated with seasonal variations in climatic conditions, and were not influenced by growth rhythms. During autumn/winter and early spring (dry period of the year) swards subjected to faster, relative to those subjected to slower rhythms of growth, had larger proportion of leaves on the top horizons. On the other hand, sward structure did not vary among rhythms of growth at times of the year when there was no limitation in the availability of climatic growth factors (late spring and summer), indicating that when control of the grazing process is efficient, changes in sward structure are basically a function of seasonal variations in climatic growth conditions and phenological state of plants.



2003 ◽  
Vol 18 (1) ◽  
pp. 29-38 ◽  
Author(s):  
Reza Yazdani ◽  
Jan-erik Nilsson ◽  
Christophe Plomion ◽  
Gaurov Mathur


Planta Medica ◽  
2016 ◽  
Vol 81 (S 01) ◽  
pp. S1-S381
Author(s):  
MD López ◽  
P Jara ◽  
S Fischer ◽  
R Wilckens ◽  
H Serri ◽  
...  


2020 ◽  
pp. 50-64
Author(s):  
Kuladeep Kumar Sadevi ◽  
Avlokita Agrawal

With the rise in awareness of energy efficient buildings and adoption of mandatory energy conservation codes across the globe, significant change is being observed in the way the buildings are designed. With the launch of Energy Conservation Building Code (ECBC) in India, climate responsive designs and passive cooling techniques are being explored increasingly in building designs. Of all the building envelope components, roof surface has been identified as the most significant with respect to the heat gain due to the incident solar radiation on buildings, especially in tropical climatic conditions. Since ECBC specifies stringent U-Values for roof assembly, use of insulating materials is becoming popular. Along with insulation, the shading of the roof is also observed to be an important strategy for improving thermal performance of the building, especially in Warm and humid climatic conditions. This study intends to assess the impact of roof shading on building’s energy performance in comparison to that of exposed roof with insulation. A typical office building with specific geometry and schedules has been identified as base case model for this study. This building is simulated using energy modelling software ‘Design Builder’ with base case parameters as prescribed in ECBC. Further, the same building has been simulated parametrically adjusting the amount of roof insulation and roof shading simultaneously. The overall energy consumption and the envelope performance of the top floor are extracted for analysis. The results indicate that the roof shading is an effective passive cooling strategy for both naturally ventilated and air conditioned buildings in Warm and humid climates of India. It is also observed that a fully shaded roof outperforms the insulated roof as per ECBC prescription. Provision of shading over roof reduces the annual energy consumption of building in case of both insulated and uninsulated roofs. However, the impact is higher for uninsulated roofs (U-Value of 3.933 W/m2K), being 4.18% as compared to 0.59% for insulated roofs (U-Value of 0.33 W/m2K).While the general assumption is that roof insulation helps in reducing the energy consumption in tropical buildings, it is observed to be the other way when insulation is provided with roof shading. It is due to restricted heat loss during night.



2020 ◽  
pp. 7-10
Author(s):  
Vasiliy P. Petropavlovsky ◽  
◽  
Vyacheslav V. Marchenko ◽  
Lyudmila S. Vikulova ◽  
Olga D. Chepeleva ◽  
...  

Summary. Data on distribution of hypodermatosis among large horned cattle in Stavropol region are presented in the article. It was proved that this pathology is widespread in this region. From 12% to 38% of animals from the total number of examined livestock are affected. Ordinary subcutaneous botfly (stroma) Hypoderma bovis de Geer and south subcutaneous botfly (pischevodnik) Hypoderma lineatum de Villers parasites on large horned cattle. The species ratio of gadflies is: Hypoderma bovis (de Gee - 61.1%, Hypoderma lineatum de Villers - 38.9%). The disease is widespread in all climatic zones of Stavropol region. Animals of all age and sex groups are infected, but young animals are more often affected. Linear relationship between the indicators of the transformation of climatic conditions in Stavropol region, the spread of hypodermatosis and the timing of treatment and preventive measures were determined. Authors proved that the complete death of H. bovis and H. lineatum imago (regardless of the time of their hatching) was noted when the temperature drops to -3°C for two days. Thus, this temperature determines the start of treatment and preventive measures against hypodermatosis in the area of animal welfare. When analyzing the histomorphological changes caused by H. bovis and H. lineatum in the body of large horned cattle, perforation of the skin, swelling of adjacent tissues, disorganization of the stroma and structural elements, erythrocyte aggregation, hemorrhages, hydropic degeneration of cellular elements, tissue necrosis, polymorphonuclear leukocyte infiltration of affected organs and tissues were observed. The data on pathogenesis were presented, the analysis of economic damage and the veterinary and sanitary assessment of the products of slaughter of cattle with hypodermatosis were carried out.



2020 ◽  
Vol 14 (3) ◽  
pp. 7109-7124
Author(s):  
Nasreddine Sakhri ◽  
Younes Menni ◽  
Houari Ameur ◽  
Ali J. Chamkha ◽  
Noureddine Kaid ◽  
...  

The wind catcher or wind tower is a natural ventilation technique that has been employed in the Middle East region and still until nowadays. The present paper aims to study the effect of the one-sided position of a wind catcher device against the ventilated space or building geometry and its natural ventilation performance. Four models based on the traditional design of a one-sided wind catcher are studied and compared. The study is achieved under the climatic conditions of the South-west of Algeria (arid region). The obtained results showed that the front and Takhtabush’s models were able to create the maximum pressure difference (ΔP) between the windward and leeward of the tower-house system. Internal airflow velocities increased with the increase of wind speed in all studied models. For example, at Vwind = 2 m/s, the internal flow velocities were 1.7, 1.8, 1.3, and 2.5 m/s for model 1, 2, 3, and 4, respectively. However, at Vwind = 6 m/s, the internal flow velocities were 5.6, 5.5, 2.5, and 7 m/s for model 1, 2, 3, and 4, respectively. The higher internal airflow velocities are given by Takhtabush, traditional, front and middle tower models, respectively, with a reduction rate between the tower outlet and occupied space by 72, 42, 36, and 33% for the middle tower, Takhtabush, traditional tower, and the front model tower, respectively. This reduction is due to the due to internal flow resistance. The third part of the study investigates the effect of window (exist opening) position on the opposite wall. The upper, middle and lower window positions are studied and compared. The air stagnation or recirculation zone inside the ventilated space reduced from 55% with the lower window to 46% for the middle window and reached 35% for the upper window position. The Front and Takhtabush models for the one-sided wind catcher with an upper window position are highly recommended for the wind-driven natural ventilation in residential houses that are located in arid regions.



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