scholarly journals Pollinator behaviour and resource limitation maintain honest floral signalling

2021 ◽  
Author(s):  
A.C. Knauer ◽  
H. Kokko ◽  
F.P. Schiestl
Keyword(s):  
Resource Limitation ◽  
Pollinator Behaviour

scholarly journals A comparative study on the reproductive success of two rewarding Habenaria species (Orchidaceae) occurring in roadside verge habitats

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Wenliu Zhang ◽  
Jiangyun Gao
Keyword(s):  
Reproductive Success ◽  
Fruit Set ◽  
Plant Density ◽  
Flowering Plant ◽  
Floral Display ◽  
Pollinator Behaviour ◽  
Factors Affecting ◽  
Nectar Sugar ◽  
Viable Seeds ◽  
Viable Embryo

Abstract Background Most orchid species have been shown to be severely pollination limited, and the factors affecting reproductive success have been widely studied. However, the factors determining the reproductive success vary from species to species. Habenaria species typically produce nectar but exhibit variable fruit set and reproductive success among species. Here, we investigated the influence of the flowering plant density, inflorescence size, breeding system, and pollinator behaviour on the reproductive success of two rewarding Habenaria species. Results Our observations indicated that Habenaria limprichtii and H. petelotii co-occur in roadside verge habitats and present overlapping flowering periods. Both species were pollination limited, although H. limprichtii produced more fruits than H. petelotii under natural conditions during the 3-year investigation. H. petelotii individuals formed distinct patches along roadsides, while nearly all H. limprichtii individuals clustered together. The bigger floral display and higher nectar sugar concentration in H. limprichtii resulted in increased attraction and visits from pollinators. Three species of effective moths pollinated for H. limprichtii, while Thinopteryx delectans (Geometridae) was the exclusive pollinator of H. petelotii. The percentage of viable seeds was significantly lower for hand geitonogamy than for hand cross-pollination in both species. However, H. limprichtii may often be geitonogamously pollinated based on the behaviours of the pollinators and viable embryo assessment. Conclusions In anthropogenic interference habitats, the behaviours and abundance of pollinators influence the fruit set of the two studied species. The different pollinator assemblages in H. limprichtii can alleviate pollinator specificity and ensure reproductive success, whereas the more viable embryos of natural fruit seeds in H. petelotii suggested reducing geitonogamy by pollinators in the field. Our results indicate that a quantity-quality trade-off must occur between species with different breeding strategies so that they can fully exploit the existing given resources.

Mass-Casualty Training Exercise Using High-Fidelity Computerized Simulators and Involving Time and Resource Limitation

2021 ◽  
Vol 36 (3) ◽  
pp. 313-320
Author(s):  
Phillip A. Jacobson ◽  
Paul N. Severin ◽  
Dino P. Rumoro ◽  
Shital Shah
Keyword(s):  
Health Care ◽  
Resource Limitation ◽  
Mass Casualty ◽  
Health Care Personnel ◽  
High Fidelity ◽  
Medical Team ◽  
Training Exercise ◽  
The Mean ◽  
Medical Teams

AbstractPurpose:Training emergency department (ED) personnel in the care of victims of mass-casualty incidents (MCIs) is a highly challenging task requiring unique and innovative approaches. The purpose of this study was to retrospectively explore the value of high-fidelity simulators in an exercise that incorporates time and resource limitation as an optimal method of training health care personnel in mass-casualty care.Methods:Mass-casualty injury patterns from an explosive blast event were simulated for 12 victims using high-fidelity computerized simulators (HFCS). Programmed outcomes, based on the nature of injuries and conduct of participants, ranged from successful resuscitation and survival to death. The training exercise was conducted five times with different teams of health care personnel (n = 42). The exercise involved limited time and resources such as blood, ventilators, and imaging capability. Medical team performance was observed and recorded. Following the exercise, participants completed a survey regarding their training satisfaction, quality of the exercise, and their prior experiences with MCI simulations. The Likert scale responses from the survey were evaluated using mean with 95% confidence interval, as well as median and inter-quartile range. For the categorical responses, the frequency, proportions, and associated 95% confidence interval were calculated.Results:The mean rating on the quality of experiences related trainee survey questions (n = 42) was between 4.1 and 4.6 on a scale of 5.0. The mean ratings on a scale of 10.0 for quality, usefulness, and pertinence of the program were 9.2, 9.5, and 9.5, respectfully. One hundred percent of respondents believed that this type of exercise should be required for MCI training and would recommend this exercise to colleagues. The five medical team (n = 5) performances resulted in the number of deaths ranging from two (including the expectant victims) to six. Eighty percent of medical teams attempted to resuscitate the “expectant” infant and exhausted the O- blood supply. Sixty percent of medical teams depleted the supply of ventilators. Forty percent of medical teams treated “delayed” victims too early.Conclusion:A training exercise using HFCS for mass casualties and employing limited time and resources is described. This exercise is a preferred method of training among participating health care personnel.

Pollination and resource limitation as interacting constraints on almond fruit set

Plant Biology ◽  
2019 ◽  
Vol 22 (1) ◽  
pp. 113-119
Author(s):  
S. A. Cunningham ◽  
M. J. Evans ◽  
M. Neave ◽  
J. Armstrong ◽  
P. S. Barton
Keyword(s):  
Fruit Set ◽  
Resource Limitation

scholarly journals Seasonal quantitative dynamics and ecology of pelagic rotifers in an acidified boreal lake

2017 ◽  
Vol 77 (1) ◽  
Author(s):  
Svein Birger Wærvågen ◽  
Tom Andersen
Keyword(s):  
Community Structure ◽  
Environmental Gradients ◽  
Seasonal Succession ◽  
Biotic Interactions ◽  
Resource Limitation ◽  
Local Environment ◽  
Food Competition ◽  
Variance Partitioning ◽  
Boreal Lake ◽  
Rotifer Community

Lake Gjerstadvann is a dimictic, oligotrophic, slightly acidified boreal lake in southern Norway (northwest Europe). The planktonic rotifer community of this lake was studied quantitatively during one year in order to investigate the impacts of the local environment and biotic interactions on seasonal succession and habitat selection. Pure suspension feeders (mainly Keratella spp., Conochilus spp., and Kellicottia longispina) together with raptorial graspers or specialised feeders (mainly Polyarthra spp. and Collotheca spp.) dominated the rotifer community over prolonged periods, whereas carnivorous/omnivorous species (mainly Asplanchna priodonta) were extremely uncommon. Low bicarbonate buffering capacity resulted in a distinctive seasonal oscillating pH between 5.0 and 5.6, defining a special acid-transition lake category. The pH values were highest in the productive period during summer, and lowest during ice break-up coinciding with the peak reactive aluminium concentrations of 250-300 mg L-1. As in typical Norwegian boreal perch lakes, the most abundant cladoceran was Bosmina longispina due to perch predation on the genus Daphnia. Rotifer community structure was significantly related to temperature and oxygen (P=0.001 and P=0.022), illustrating the important effects of the seasonal cycle and vertical density stratification. The most significant competition indicator species were B. longispina and Eudiaptomus gracilis (both with P=0.001). A variance partitioning indicated that 14% of the total community composition variance could only be explained by biotic interactions, while 19% of the variance could be attributed to environmental gradients. Of the variance, 23% could not be resolved between biotic interactions and environmental gradients, while a residual of 44% was not explainable by any of the variables. Acid conditions alone cannot account for all the observed changes in the rotifer community of this lake with low humic content, since resource limitation and food competition are also important factors shaping rotifer population dynamics and the community structure.

scholarly journals Habitat-mediated population limitation in a colonial central-place forager: the sky is not the limit for the black-browed albatross

2014 ◽  
Vol 281 (1778) ◽  
pp. 20132883 ◽  
Author(s):  
Ewan D. Wakefield ◽  
Richard A. Phillips ◽  
Jason Matthiopoulos
Keyword(s):  
Resource Availability ◽  
Net Primary Production ◽  
Strong Dependence ◽  
Resource Limitation ◽  
Central Place ◽  
Population Limitation ◽  
Animal Populations ◽  
Temporal Predictability ◽  
Spatio Temporal ◽  
The Cost

Animal populations are frequently limited by the availability of food or of habitat. In central-place foragers, the cost of accessing these resources is distance-dependent rather than uniform in space. However, in seabirds, a widely studied exemplar of this paradigm, empirical population models have hitherto ignored this cost. In part, this is because non-independence among colonies makes it difficult to define population units. Here, we model the effects of both resource availability and accessibility on populations of a wide-ranging, pelagic seabird, the black-browed albatross Thalassarche melanophris . Adopting a multi-scale approach, we define regional populations objectively as spatial clusters of colonies. We consider two readily quantifiable proxies of resource availability: the extent of neritic waters (the preferred foraging habitat) and net primary production (NPP). We show that the size of regional albatross populations has a strong dependence, after weighting for accessibility, on habitat availability and to a lesser extent, NPP. Our results provide indirect support for the hypothesis that seabird populations are regulated from the bottom-up by food availability during the breeding season, and also suggest that the spatio-temporal predictability of food may be limiting. Moreover, we demonstrate a straightforward, widely applicable method for estimating resource limitation in populations of central-place foragers.

scholarly journals Superficial venous insufficiency from the infernal to the endothermal

2014 ◽  
Vol 96 (1) ◽  
pp. 5-10 ◽  
Author(s):  
D Carradice
Keyword(s):  
Gold Standard ◽  
Venous Insufficiency ◽  
Varicose Veins ◽  
Treatment Options ◽  
Resource Limitation ◽  
Skin Damage ◽  
The Common ◽  
Modern Treatment ◽  
The Cost ◽  
Superficial Venous Insufficiency

This review presents the common diseases associated with superficial venous insufficiency of the leg. These include varicose veins, swelling, skin damage and ulceration. The benefits and rationale behind treatment are discussed, followed by the historical advances from ancient mortality and prayer to the modern endovenous revolution. Finally, an overview of modern treatment options will discuss the evidence supporting the gold standard of endothermal ablation and the cost effectiveness of treatment at this time of challenging resource limitation.

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