The relationship between crop size and fruit removal and its implication for the evolution of dioecy

1992 ◽  
Vol 70 (9) ◽  
pp. 1784-1789 ◽  
Author(s):  
David E. Carr
Keyword(s):  
Empirical Studies ◽  
Stable State ◽  
Relative Fitness ◽  
Female Fitness ◽  
Fruit Removal ◽  
Crop Size ◽  
Fruit Crop ◽  
The Stability ◽  
Evolution Of Dioecy ◽  
The Relationship

The number of fruits removed by birds from individual Ilex opaca (Aquifoliaceae) was found to increase as a function of crop size in both 1986 and 1987. The proportion of the fruit crop removed, however, was not significantly affected by crop size in either year. In 1986 the increase in relative female fitness as a function of crop size rapidly became asymptotic. In 1987 relative female fitness increased more linearly over the range of fruit crop sizes. Differences between years were attributed to differences in disperser abundance. The change in relative fitness with increasing crop size was not sufficient to explain the evolutionary stability of dioecy under conditions such as those in 1986 (i.e., asymptotic fitness gains). Under conditions of more proportional increases in relative fitness (as seen in 1987), circumstances became more favorable for the stability of dioecy, though still not sufficient. This and other empirical studies of the response of avian dispersers to variation in fruit crop size suggest that selection for increased crop size is not likely, by itself, to be strong enough to allow dioecy to exist in a stable state. I suggest that the combined effects of sexual selection (especially through male–male competition) and inbreeding depression will be more important than the effect of differential dispersal success for the evolution and maintenance of dioecy in plants. Key words: dioecy, dispersal, frugivore, holly, Ilex.

Effects of Fruit Crop Size on Intensity of Fruit Removal in Viburnum prunifolium (Caprifoliaceae)

Oikos ◽  
1994 ◽  
Vol 69 (2) ◽  
pp. 199 ◽  
Author(s):  
Mark S. Laska ◽  
Edmund W. Stiles
Keyword(s):  
Fruit Removal ◽  
Crop Size ◽  
Fruit Crop ◽  
Fruit Crop Size

Study on the Model of the Stability of International Energy Cooperative

2014 ◽  
Vol 672-674 ◽  
pp. 2122-2126
Author(s):  
Chao Gong ◽  
Hong Li Yang ◽  
Qi Wang
Keyword(s):  
World Economy ◽  
Stable State ◽  
Cooperative System ◽  
Internal Factor ◽  
Endogenous Factors ◽  
State Of The Economy ◽  
Endogenous Variables ◽  
The Stability ◽  
Cooperation System ◽  
The Relationship

The world economy entering the era of cooperation and competition, in this case, cooperation has become the basic state of the economy. During the developing process, the change of cooperative stability, which determines cooperative trajectory, is a key scientific problem on collaboration. Cooperative intensity, whose size directly determines the intensity of stability on the cooperation system and affects the evolutive boundary of the cooperative system, is endogenous variables affecting the cooperative stability. In recent years the cooperative strength and the cooperative stability has become a hot research topic on cooperation projects. This paper, drawing on the relative research of other scholars, proposing the concept of cooperative strength, which to discuss how did the endogenous factors affect the cooperative stability, using the relationship between them, builds the model of cooperative stability according with the energy fields, and verifies the existence of stability in cooperative system. The results show that in the evolution of stability of cooperative system, cooperative strength is the internal factor which determines the cooperitive stability. The interaction among the effective factors of the cooperative strength restricts the trajectory of cooperative stability. Its trajectory is complex, but there is still a boundary, which can make cooperative system reach stable state.

scholarly journals Crop damage of Eriotheca gracilipes (Bombacaceae) by the Blue-Fronted Amazon (Amazona aestiva, Psittacidae), in the Brazilian Cerrado

2014 ◽  
Vol 74 (4) ◽  
pp. 837-843 ◽  
Author(s):  
J Ragusa-Netto
Keyword(s):  
Seed Predation ◽  
Interspecific Interactions ◽  
Crop Damage ◽  
Crop Loss ◽  
Fruit Crops ◽  
Crop Size ◽  
Fruit Crop ◽  
Seed Survival ◽  
The Relationship ◽  
Fruit Crop Size

Seed predation has major effects on the reproductive success of individuals, spatial patterns of populations, genetic variability, interspecific interactions and ultimately in the diversity of tree communities. At a Brazilian savanna, I evaluated the proportional crop loss of Eriotheca gracilipes due the Blue-Fronted Amazon (Amazona aestiva) during a fruiting period. Also, I analyzed the relationship between proportional crop loss to Amazons and both fruit crop size and the distance from the nearest damaged conspecific. Trees produced from 1 to 109 fruits, so that Amazons foraged more often on trees bearing larger fruit crop size, while seldom visited less productive trees. Moreover, the relationship between fruit crop sizes and the number of depredated fruits was significant. However, when only damaged trees were assessed, I found a negative and significant relation between fruit crop size and proportional crop loss to Blue-Fronted Amazons. Taking into account this as a measure more directly related to the probability of seed survival, a negative density dependent effect emerged. Also, Amazons similarly damaged the fruit crops of either close or distant neighboring damaged trees. Hence, in spite of Blue-Fronted Amazons searched for E. gracilipes bearing large fruit crops, they were swamped due to the presence of more fruits than they could eat. Moderate seed predation by Blue-Fronted Amazons either at trees with large fruit crops or in areas where fruiting trees were aggregated implies in an enhanced probability of E. gracilipes seed survival and consequent regeneration success.

Structure of young people’s social perceptions of Russia: the problem of identity

2020 ◽  
Vol 26 (3) ◽  
pp. 8-18
Author(s):  
Natalya P. Sashchenko
Keyword(s):  
Social Networks ◽  
Political Attitudes ◽  
Social Representations ◽  
Empirical Studies ◽  
Social Perceptions ◽  
National State ◽  
The Core ◽  
The Stability ◽  
The Relationship ◽  
Russian Identity

The article examines the relationship between social perceptions of one’s country, national-state (Russian) identity, and the stability of the state. We analyzed the results of empirical studies of social perceptions of young users of social networks with different ideological preferences and socio-political attitudes through the study of a system of images and symbols associated in the minds of youth the notion of “Russia”. The structure of social representations about Russia, the content of the core and peripheral zones, and the emotional assessment of the studied category are revealed.

The Relationship Between Fruit Crop Sizes and Fruit Removal Rates by Birds

Ecology ◽  
1986 ◽  
Vol 67 (1) ◽  
pp. 262-265 ◽  
Author(s):  
Priya Davidar ◽  
Eugene S. Morton
Keyword(s):  
Fruit Removal ◽  
Removal Rates ◽  
Fruit Crop ◽  
The Relationship

An Experimental Investigation on Thermal Conductivity and Viscosity of Graphene doped CNTs /TiO2 Nanofluid

2020 ◽  
Vol 17 (3) ◽  
Author(s):  
A.M. Zetty Akhtar ◽  
M.M. Rahman ◽  
K. Kadirgama ◽  
M.A. Maleque
Keyword(s):  
Thermal Conductivity ◽  
Zeta Potential ◽  
Base Fluid ◽  
Minimum Quantity Lubrication ◽  
Cutting Fluid ◽  
Cutting Zone ◽  
Observation Method ◽  
The Stability ◽  
The Relationship ◽  
Zeta Potential Analysis

This paper presents the findings of the stability, thermal conductivity and viscosity of CNTs (doped with 10 wt% graphene)- TiO2 hybrid nanofluids under various concentrations. While the usage of cutting fluid in machining operation is necessary for removing the heat generated at the cutting zone, the excessive use of it could lead to environmental and health issue to the operators. Therefore, the minimum quantity lubrication (MQL) to replace the conventional flooding was introduced. The MQL method minimises the usage of cutting fluid as a step to achieve a cleaner environment and sustainable machining. However, the low thermal conductivity of the base fluid in the MQL system caused the insufficient removal of heat generated in the cutting zone. Addition of nanoparticles to the base fluid was then introduced to enhance the performance of cutting fluids. The ethylene glycol used as the base fluid, titanium dioxide (TiO2) and carbon nanotubes (CNTs) nanoparticle mixed to produce nanofluids with concentrations of 0.02 to 0.1 wt.% with an interval of 0.02 wt%. The mixing ratio of TiO2: CNTs was 90:10 and ratio of SDBS (surfactant): CNTs was 10:1. The stability of nanofluid checked using observation method and zeta potential analysis. The thermal conductivity and viscosity of suspension were measured at a temperature range between 30˚C to 70˚C (with increment of 10˚C) to determine the relationship between concentration and temperature on nanofluid’s thermal physical properties. Based on the results obtained, zeta potential value for nanofluid range from -50 to -70 mV indicates a good stability of the suspension. Thermal conductivity of nanofluid increases as an increase of temperature and enhancement ratio is within the range of 1.51 to 4.53 compared to the base fluid. Meanwhile, the viscosity of nanofluid shows decrements with an increase of the temperature remarks significant advantage in pumping power. The developed nanofluid in this study found to be stable with enhanced thermal conductivity and decrease in viscosity, which at once make it possible to be use as nanolubricant in machining operation.

Spotting a liar by looking for microexpressions: Challenges and Opportunities

2019 ◽  
Author(s):  
Xunbing Shen
Keyword(s):  
Empirical Evidence ◽  
Deception Detection ◽  
Empirical Studies ◽  
High Stake ◽  
Challenges And Opportunities ◽  
Cues To Deception ◽  
The Relationship

Microexpressions do exist, and they are regarded as valid cues to deception by many researchers, furthermore, there is a lot of empirical evidence which substantiates this claim. However, some researchers don’t think the microexpression can be a way to catch a liar. The author elucidates the theories predicting that looking for microexpressions can be a way to catch a liar, and notes that some data can support for the utilization of microexpressions as a good way to detect deception. In addition, the author thinks that the mixed results in the area of investigating microexpressions and deception detection may be moderated by the stake. More empirical studies which employ high-stake lies to explore the relationship between microexpressions and deception detection are needed.

LANDSLIDE RISK MANAGEMENT IN THE COASTAL ZONE OF THE KUIBYSHEV RESERVOIR DUE THE DESIGN OF HIGH-SPEED LINE "MOSCOW-KAZAN"

2017 ◽  
Author(s):  
Nikolai Petrov ◽  
Nikolai Petrov ◽  
Inna Nikonorova ◽  
Inna Nikonorova ◽  
Vladimir Mashin ◽  
...  
Keyword(s):  
High Speed ◽  
Computational Models ◽  
Stable State ◽  
Landslide Risk ◽  
Kuibyshev Reservoir ◽  
Stepped Surface ◽  
The Stability ◽  
Landslide Slope ◽  
The Village

High-speed railway "Moscow-Kazan" by the draft crosses the Volga (Kuibyshev reservoir) in Chuvashia region 500 m below the village of New Kushnikovo. The crossing plot is a right-bank landslide slope with a stepped surface. Its height is 80 m; the slope steepness -15-16o. The authors should assess the risk of landslides and recommend anti-landslide measures to ensure the safety of the future bridge. For this landslide factors have been analyzed, slope stability assessment has been performed and recommendations have been suggested. The role of the following factors have been analyzed: 1) hydrologic - erosion and abrasion reservoir and runoff role; 2) lithologyc (the presence of Urzhum and Northern Dvina horizons of plastically deformable rocks, displacement areas); 3) hydrogeological (the role of perched, ground and interstratal water); 4) geomorphological (presence of the elemental composition of sliding systems and their structure in the relief); 5) exogeodynamic (cycles and stages of landslide systems development, mechanisms and relationship between landslide tiers of different generations and blocks contained in tiers). As a result 6-7 computational models at each of the three engineering-geological sections were made. The stability was evaluated by the method “of the leaning slope”. It is proved that the slope is in a very stable state and requires the following measures: 1) unloading (truncation) of active heads blocks of landslide tiers) and the edge of the plateau, 2) regulation of the surface and groundwater flow, 3) concrete dam, if necessary.

A FORECAST OF PRODUCTIVE LONGEVITY OF HOLSTEIN COWS BY INDIRECT SIGNS

2020 ◽  
Author(s):  
З.С. САНОВА
Keyword(s):  
Correlation Coefficient ◽  
Aging Process ◽  
Direct Relationship ◽  
Stability Index ◽  
Age At First Calving ◽  
Group I ◽  
Predicted Values ◽  
The Stability ◽  
Relationship Of ◽  
The Relationship

В статье представлены материалы о взаимосвязи продолжительности продуктивного использования коров с характеристикой устойчивости к деградации, с возрастом отела и удоем. В исследованной, разнородной по происхождению, группе животных для прогноза продуктивного периода коров, обусловленного устойчивостью к деградации и возрастом первого отела, пригодно уравнение регрессии, аргументами в котором являются индекс устойчивости, возраст первого отела в первой и второй степенях. Коэффициент корреляции межу предсказанными значениями продуктивного периода и его фактическими величинами в I группе составляет 0,502, во II - 0,604. При этом крайние варианты прогнозируются со статистическими ошибками 5 мес при оценке индекса устойчивости по 2 лактациям и 4,1 мес по 3, а средние варианты, соответственно, 1,6 и 1,51 мес. Индекс устойчивости к процессу старения является важной характеристикой биологических особенностей коров, определяющий их продуктивное долголетие. Его оценка по первым 2 и 3 лактациям имеет прямолинейную связь с продуктивным периодом (r=0,4109 и r=0,5270), соответственно. Зависимость продуктивного периода от возраста первого отела криволинейная — с увеличением возраста первого отела сокращается срок продуктивного использования, при возрасте первого отела более 1400 дней срок продуктивного использования колеблется от 1,33 до 1,41 лактации. Коэффициент корреляции между этими характеристиками коров составляет - 0,2164 в I и - 0,2620 во II группах. The article presents materials about the relationship of the duration of productive use of cows with the characteristic of resistance to degradation, with the age of calving and milk yield. In the studied group of animals, which is heterogeneous in origin, the regression equation is suitable for predicting the productive period of cows due to resistance to degradation and the age of the first calving, the arguments of which are the stability index, the age of the first calving in the first and second degrees. The correlation coefficient between the predicted values of the productive period and its actual values in group I is 0.502, in group II - 0.604. At the same time, the extreme variants are predicted with statistical errors of 5 months when evaluating the stability index for 2 lactations and 4.1 months for 3, and the average variants, respectively, are 1.6 and 1.51 months. The index of resistance to the aging process is an important characteristic of the biological characteristics of cows, which determines their productive longevity. Its estimate for the first 2 and 3 lactations has a direct relationship with the productive period (r=0.4109 and r=0.5270), respectively. The dependence of the productive period age at first calving curvilinear with increasing age at first calving reduces the time to productive use, while age at first calving of more than 1400 days, the period of productive use ranges from 1.33 to 1.41 lactation. The correlation coefficient between these characteristics of cows is-0.2164 in I and-0.2620 in II groups.

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