scholarly journals Correlated seed failure as an environmental veto to synchronize reproduction of masting plants

2017 ◽  
Author(s):  
Michał Bogdziewicz ◽  
Michael A. Steele ◽  
Shealyn Marino ◽  
Elizabeth E. Crone
Keyword(s):  
Seed Production ◽  
Large Scale ◽  
Pollen Limitation ◽  
Reproductive Failure ◽  
Pollination Success ◽  
Proximate Mechanisms ◽  
Weather Events ◽  
Resource Dynamics ◽  
Resource Budget Model ◽  
Necessary And Sufficient

Highly variable, synchronized seed production, called masting, is a widespread reproductive strategy in plants. Resource dynamics, pollination success, and, as described here, environmental veto, are possible proximate mechanisms of masting. We extended the resource budget model of masting with correlated and uncorrelated reproductive failure, and ran this model across its parameters space. Next, we parametrized the model based on a 16-year seed production data for red (Quercus rubra) and white (Q. alba) oaks. Simulations showed that resource dynamics and reproduction failure produce masting even in the absence of pollen coupling. In concordance, in both species, among-year variation in resource gain and correlated reproductive failure were necessary and sufficient to produce masting. Environmental variation is a form of reproduction failure caused by environmental veto that may drive large-scale synchronization without density-dependent pollen limitation. Reproductive-inhibiting weather events are prevalent in ecosystems, suggesting that these described mechanisms likely operate in many masting systems.

Sex-ratio variation versus interplant distances in the regulation of pollen deposition and seed production in dioecious Cirsium arvense (Asteraceae)1This article is part of a Special Issue entitled “Pollination biology research in Canada: Perspectives on a mutualism at different scales”.

Botany ◽  
2012 ◽  
Vol 90 (7) ◽  
pp. 565-573 ◽  
Author(s):  
Wendy E. Van Drunen ◽  
Marcel E. Dorken
Keyword(s):  
Seed Production ◽  
Pollen Limitation ◽  
Sex Ratios ◽  
Cirsium Arvense ◽  
Pollen Deposition ◽  
Dioecious Plants ◽  
Pollination Success ◽  
Variation Versus ◽  
Broad Variation ◽  
Pollen Receipt

Pollination success in dioecious plants is expected to be regulated by the ratio of female:male plants and the distances between plants of each sex. These factors have received considerable attention in studies of dioecious and other gender dimorphic plants, yet their effects have rarely been jointly considered. We documented sex ratios in 26 populations of Cirsium arvense (L.) Scop. (creeping thistle), a widely distributed clonal dioecious plant, and show that population sex ratios are generally female biased (∼60% of shoots were female, and 15 of 26 populations were female biased). We found clear evidence for a negative association between pollen loads and distances between females and males within populations. In contrast, and in spite of broad variation in sex ratios among populations (range: 0.11–0.99 female), we found no relationship between sex ratios and pollen receipt by females. However, both sex ratios and interplant distances were associated with female seed production: seed production declined with distances between females and males and increased with the proportion of male shoots. Our data suggest that female plants of C. arvense might often be pollen limited and that distances between individual females and males drive pollen limitation more strongly than the overall frequency of males within sites.

scholarly journals Development and Evaluation of Geostatistical Methods for Estimating Weather Related Collisions: A Large-Scale Case Study

2021 ◽  
pp. 036119812110200
Author(s):  
Andy H. Wong ◽  
Tae J. Kwon
Keyword(s):  
Large Scale ◽  
Mean Squared Error ◽  
Hot Spot ◽  
High Ratio ◽  
Contributing Factors ◽  
Geostatistical Methods ◽  
Road Users ◽  
Statistical Measures ◽  
Weather Events

Winter driving conditions pose a real hazard to road users with increased chance of collisions during inclement weather events. As such, road authorities strive to service the hazardous roads or collision hot spots by increasing road safety, mobility, and accessibility. One measure of a hot spot would be winter collision statistics. Using the ratio of winter collisions (WC) to all collisions, roads that show a high ratio of WC should be given a high priority for further diagnosis and countermeasure selection. This study presents a unique methodological framework that is built on one of the least explored yet most powerful geostatistical techniques, namely, regression kriging (RK). Unlike other variants of kriging, RK uses auxiliary variables to gain a deeper understanding of contributing factors while also utilizing the spatial autocorrelation structure for predicting WC ratios. The applicability and validity of RK for a large-scale hot spot analysis is evaluated using the northeast quarter of the State of Iowa, spanning five winter seasons from 2013/14 to 2017/18. The findings of the case study assessed via three different statistical measures (mean squared error, root mean square error, and root mean squared standardized error) suggest that RK is very effective for modeling WC ratios, thereby further supporting its robustness and feasibility for a statewide implementation.

scholarly journals Lipid and Yield Evaluation in Salicornia bigelovii by the Influence of Chitosan-IBA, in Conditions of the Sonora Desert

Agronomy ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 428
Author(s):  
Gerardo Zapata-Sifuentes ◽  
Pablo Preciado-Rangel ◽  
Reyna Roxana Guillén-Enríquez ◽  
Francisca Sánchez Bernal ◽  
Ramon Jaime Holguin-Peña ◽  
...  
Keyword(s):  
Lipid Profile ◽  
Seed Production ◽  
Butyric Acid ◽  
Lipid Content ◽  
Production System ◽  
Large Scale ◽  
Physicochemical Analysis ◽  
Indole Butyric Acid ◽  
Salicornia Bigelovii ◽  
Yield Production

The present investigation aimed to evaluate the effect of Chitosan-Indole Butyric Acid (IBA) in the seed of Salicornia bigelovii under field conditions in Sonora, Mexico. During two vegetative cycles (2018/2019–2019/2020), cuttings of S. bigelovii were treated with 100 and 50% Chitosan from shrimp exoskeletons and indole butyric acid at 0.937 and 1.25 g·kg−1 and placed in basins under conditions of the Sonora desert, Mexico. Variables were measured: seed production, physicochemical analysis and lipid profile of the seed. The results affected significant increases (p < 0.05) in the evaluated variables, highlighting the treatment based on Chitosan 100%—IBA 0.937 g·kg−1. The results based on chitosan and IBA in cuttings, are a biostimulant in the morpho-physiology, yield production, and lipid content of S. bigelovii. Large-scale studies as a production system should be considered in further studies.

The entrainment interface

1972 ◽  
Vol 51 (1) ◽  
pp. 97-118 ◽  
Author(s):  
O. M. Phillips
Keyword(s):  
Velocity Field ◽  
Turbulent Flow ◽  
Surface Area ◽  
Large Scale ◽  
Positive Curvature ◽  
Lagrangian Description ◽  
Eulerian Description ◽  
Entrainment Process ◽  
Necessary And Sufficient ◽  
Small Disturbances

A theory is developed to describe the evolution of the entrainment interface in turbulent flow, in which the surface is convoluted by the large-scale eddies of the motion and at the same time advances relative to the fluid as a result of the micro-scale entrainment process. A pseudo-Lagrangian description of the process indicates that the interface is characterized by the appearance of ‘billows’ of negative curvature, over which surface area is, on average, being generated, separated by re-entrant wedges (lines of very large positive curvature) where surface area is consumed. An alternative Eulerian description allows calculation of the development of the interfacial configuration when the velocity field is prescribed. Several examples are considered in which the prescribed velocity field in the z direction is of the general form w = Wf(x – Ut), where the maximum value of the function f is unity. These indicate the importance of leading points on the surface which are such that small disturbances in the vicinity will move away from the point in all directions. The necessary and sufficient condition for the existence of one or more leading points on the surface is that U [les ] V, the speed of advance of an element of the surface relative to the fluid element at the same point. The existence of leading points is accompanied by the appearance of line discontinuities in the surface slope re-entrant wedges, In these circumstances, the overall speed of advance of the convoluted surface is found to be W + (V2 – U2)½, where W is the maximum outwards velocity in the region; this result is independent of the distribution f.When the speed U with which an ‘eddy’ moves relative to the outside fluid is greater than the speed of advance V of an element of the front, the interface develops neither leading points nor discontinuities in slope; the amplitude of the surface convolutions and the overall entrainment speed are both reduced greatly. In a turbulent flow, therefore, the large-scale motions influencing entrainment are primarily those that move slowly relative to the outside fluid (with relative speed less than V). The experimental results of Kovasznay, Kibens & Blackwelder (1970) are reviewed in the light of these conclusions. It appears that in their experiments the entrainment speed V is of the order fifteen times the Kolmogorov velocity, the large constant of proportionality being apparently the result of augmentation by micro-convolutions of the interface associated with small and meso-scale eddies of the turbulence.

scholarly journals Controllability and Observability of a Large Scale Thermodynamical System via Connectability Approach

2010 ◽  
Author(s):  
Virdiansyah Permana ◽  
Rahmat Shoureshi
Keyword(s):  
Graph Theory ◽  
Lie Algebra ◽  
Large Scale ◽  
Point Of View ◽  
Rank Condition ◽  
Computational Point ◽  
New Approach ◽  
Class System ◽  
Necessary And Sufficient ◽  
Controllability And Observability

This study presents a new approach to determine the controllability and observability of a large scale nonlinear dynamic thermal system using graph-theory. The novelty of this method is in adapting graph theory for nonlinear class and establishing a graphic condition that describes the necessary and sufficient terms for a nonlinear class system to be controllable and observable, which equivalents to the analytical method of Lie algebra rank condition. The directed graph (digraph) is utilized to model the system, and the rule of its adaptation in nonlinear class is defined. Subsequently, necessary and sufficient terms to achieve controllability and observability condition are investigated through the structural property of a digraph called connectability. It will be shown that the connectability condition between input and states, as well as output and states of a nonlinear system are equivalent to Lie-algebra rank condition (LARC). This approach has been proven to be easier from a computational point of view and is thus found to be useful when dealing with a large system.

scholarly journals Fast Playback Framework for Analysis of Ground-Based Doppler Radar Observations Using MapReduce Technology

2016 ◽  
Vol 33 (4) ◽  
pp. 621-634 ◽  
Author(s):  
Jingyin Tang ◽  
Corene J. Matyas
Keyword(s):  
Spatial Analysis ◽  
High Performance ◽  
Large Scale ◽  
Doppler Radar ◽  
Weather Events ◽  
Data Architecture ◽  
Research Grade ◽  
High Performance Computing Cluster ◽  
Time Systems ◽  
Performance Computing

AbstractThe creation of a 3D mosaic is often the first step when using the high-spatial- and temporal-resolution data produced by ground-based radars. Efficient yet accurate methods are needed to mosaic data from dozens of radar to better understand the precipitation processes in synoptic-scale systems such as tropical cyclones. Research-grade radar mosaic methods of analyzing historical weather events should utilize data from both sides of a moving temporal window and process them in a flexible data architecture that is not available in most stand-alone software tools or real-time systems. Thus, these historical analyses require a different strategy for optimizing flexibility and scalability by removing time constraints from the design. This paper presents a MapReduce-based playback framework using Apache Spark’s computational engine to interpolate large volumes of radar reflectivity and velocity data onto 3D grids. Designed as being friendly to use on a high-performance computing cluster, these methods may also be executed on a low-end configured machine. A protocol is designed to enable interoperability with GIS and spatial analysis functions in this framework. Open-source software is utilized to enhance radar usability in the nonspecialist community. Case studies during a tropical cyclone landfall shows this framework’s capability of efficiently creating a large-scale high-resolution 3D radar mosaic with the integration of GIS functions for spatial analysis.

scholarly journals Floral Biology and Seed Production in Cultivated North American Ginseng (Panax quinquefolius)

2000 ◽  
Vol 125 (5) ◽  
pp. 567-575 ◽  
Author(s):  
Cayetana Schluter ◽  
Zamir K. Punja
Keyword(s):  
Seed Production ◽  
North American ◽  
Age Groups ◽  
Morphological Characteristics ◽  
Floral Biology ◽  
American Ginseng ◽  
Panax Quinquefolius ◽  
Flowering Period ◽  
Pollination Success ◽  
Pollen Release

Morphological characteristics of flowers, duration of flowering, degree of self-pollination, and extent of berry and seed production in North American ginseng (Panax quinquefolius L.) were studied under controlled environmental conditions as well as under field conditions. A comparison was also made between plants of 3 and 4 years of age at two field locations. The duration of flowering was ≈4 weeks and was similar in plants of both age groups grown in the two environments; however, 4-year-old plants produced an average of 40% more flowers (≈100 per plant in total) compared to 3-year-old plants. Flowers were comprised of five greenish-colored petals, five stamens, and an inferior ovary consisting of predominantly two fused carpels and stigmatic lobes. Anthers dehisced in staggered succession within individual flowers, and flowering began with the outermost edge of the umbel and proceeded inwards. At any given time during the 4-week flowering period, ≈10% of the flowers in an umbel had recently opened and were producing pollen. Stigma receptivity was associated with separation of the stigmatic lobes; this occurred at some time after pollen release. Growth of pollen tubes through the style in naturally pollinated flowers was most evident when the stigmatic lobes had separated. The proportion of flowers that developed into mature berries (pollination success rate) was in the range of 41% to 68% for both 3-year-old and 4-year-old plants. However, when the inflorescence was bagged during the flowering period, berry formation was increased by 13% to 21% in 4-year-old plants, depending on location. A majority of the berries (92% to 99%) contained one or two seeds in an almost equal frequency, with the remaining berries containing three seeds. In 4-year-old plants, the frequency of two-seeded berries was increased by ≈13% by bagging the inflorescence. These observations indicate that P. quinquefolius is highly self-fertile and that several physiological and environmental factors can affect seed production.

scholarly journals Influence of local and large-scale weather events and timing of breeding on tropical roseate tern reproductive parameters

2002 ◽  
Vol 243 ◽  
pp. 271-279 ◽  
Author(s):  
JA Ramos ◽  
AM Maul ◽  
V Ayrton ◽  
I Bullock ◽  
J Hunter ◽  
...  
Keyword(s):  
Large Scale ◽  
Timing Of Breeding ◽  
Reproductive Parameters ◽  
Weather Events ◽  
Roseate Tern

Hotspots of extreme compound drought and heatwaves: Role of feedback and climate oscillations

2021 ◽  
Author(s):  
Waqar Ul Hassan ◽  
Munir Ahmad Nayak
Keyword(s):  
Large Scale ◽  
Southern Oscillation ◽  
Standardized Precipitation Index ◽  
Limited Attention ◽  
Weather Events ◽  
Excess Heat Factor ◽  
Climatic Drivers ◽  
Compound Events ◽  
Positive And Negative Feedbacks

&lt;p&gt;Compound weather events arise from combination of multiple climatic drivers or hazards and often result in disastrous socio-economic impacts. Compound drought and heatwave (CDHE) events have received considerable attention in recent years, but limited attention is given towards the understanding of feedback relationships between droughts and heatwaves at global hotspots of the compound events. Here, we identify the potential hotspots of extreme compound drought and heatwaves (ECDH) over the globe using standardized precipitation index (SPI) and Excess heat factor (EHF) as metrics for droughts and heatwaves, respectively. Besides the well know positive feedback between droughts and heatwaves, i.e., heatwaves amplify droughts and vice-versa, we hypothesize and test the possibility of negative feedback at distinct hotspots where heatwaves tend to abate droughts. Multiple hotspots were identified with positive and negative feedbacks among drought and heatwave intensities, supporting our hypothesis. We also analyzed the role of different local and large-scale global drivers (such as El-Ni&amp;#241;o Southern Oscillation) on the feedbacks at the hotspots. Our analysis has implications in predicting extreme compound droughts and heatwaves and provides new insights that will foster further research in this direction.&lt;/p&gt;

Self Adaptive Particle Swarm Optimization for Efficient Virtual Machine Provisioning in Cloud

2012 ◽  
pp. 88-107 ◽  
Author(s):  
R. Jeyarani ◽  
N. Nagaveni ◽  
R. Vasanth Ram
Keyword(s):  
Particle Swarm Optimization ◽  
Large Scale ◽  
Virtual Machines ◽  
Particle Swarm ◽  
Swarm Optimization ◽  
Adaptive Particle Swarm Optimization ◽  
Resource Dynamics ◽  
Virtual Machine Provisioning ◽  
Dynamic Resource ◽  
Self Adaptive

Cloud Computing provides dynamic leasing of server capabilities as a scalable, virtualized service to end users. The discussed work focuses on Infrastructure as a Service (IaaS) model where custom Virtual Machines (VM) are launched in appropriate servers available in a data-center. The context of the environment is a large scale, heterogeneous and dynamic resource pool. Nonlinear variation in the availability of processing elements, memory size, storage capacity, and bandwidth causes resource dynamics apart from the sporadic nature of workload. The major challenge is to map a set of VM instances onto a set of servers from a dynamic resource pool so the total incremental power drawn upon the mapping is minimal and does not compromise the performance objectives. This paper proposes a novel Self Adaptive Particle Swarm Optimization (SAPSO) algorithm to solve the intractable nature of the above challenge. The proposed approach promptly detects and efficiently tracks the changing optimum that represents target servers for VM placement. The experimental results of SAPSO was compared with Multi-Strategy Ensemble Particle Swarm Optimization (MEPSO) and the results show that SAPSO outperforms the latter for power aware adaptive VM provisioning in a large scale, heterogeneous and dynamic cloud environment.

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