scholarly journals Factors influencing long-term population dynamics of pronghorn (Antilocapra americana): evidence of an Allee effect

2010 ◽  
Vol 91 (5) ◽  
pp. 1124-1134 ◽  
Author(s):  
Justin D. Hoffman ◽  
Hugh H. Genoways ◽  
Rachel R. Jones
Keyword(s):  
Population Dynamics ◽  
Allee Effect ◽  
Antilocapra Americana ◽  
Factors Influencing

Long-term population dynamics of the red deer and European roe deer at the protected and not-protected areas in Mountain Crimea

2017 ◽  
Vol 7 (4) ◽  
pp. 65-72
Author(s):  
V. N. Shmagol' ◽  
V. L. Yarysh ◽  
S. P. Ivanov ◽  
V. I. Maltsev
Keyword(s):  
Population Dynamics ◽  
Protected Areas ◽  
Red Deer ◽  
Nature Reserve ◽  
Roe Deer ◽  
Precipitation Amount ◽  
Annual Precipitation ◽  
Population Number ◽  
The Impact

<p>The long-term population dynamics of the red deer (<em>Cervus elaphus</em> L.) and European roe deer (<em>Capreolus</em> <em>capreolus</em> L.) at the mountain and forest zone of Crimea during 1980-2017 is presented. Fluctuations in numbers of both species are cyclical and partly synchronous. Period of oscillations in the population of red deer is about 25 years, the average duration of the oscillation period of number of roe deer is 12.3 years. During the fluctuations in the number the increasing and fall in population number of the red deer had been as 26-47 %, and roe deer – as 22-34 %. Basing on the dada obtained we have assumed that together with large-scale cycles of fluctuations in population number of both red deer and roe deer the short cycles of fluctuations in the number of these species with period from 3.5 to 7.5 years take place. Significant differences of the parameters of cyclical fluctuations in the number of roe deer at some sites of the Mountainous Crimea: breaches of synchronicity, as well as significant differences in the duration of cycles are revealed. The greatest deviations from the average values of parameters of long-term dynamics of the number of roe deer in Crimea are noted for groups of this species at two protected areas. At the Crimean Nature Reserve the cycle time of fluctuations of the numbers of roe deer was 18 years. At the Karadag Nature Reserve since 1976 we can see an exponential growth in number of roe deer that is continued up to the present time. By 2016 the number of roe deer reached 750 individuals at a density of 437 animals per 1 thousand ha. Peculiarity of dynamics of number of roe deer at some sites proves the existence in the mountain forest of Crimea several relatively isolated groups of deer. We assumed that "island" location of the Crimean populations of red deer and European roe deer, their relatively little number and influence of permanent extreme factors of both natural and anthropogenic origination have contributed to a mechanism of survival of these populations. The elements of such a mechanism include the following features of long-term dynamics of the population: the reduction in the period of cyclic population fluctuations, while maintaining their amplitude and the appearance of additional small cycles, providing more flexible response of the population to the impact of both negative and positive environmental factors. From the totality of the weather conditions for the Crimean population of roe deer the recurring periods of increases and downs in the annual precipitation amount may have relevance. There was a trend of increase in the roe deer population during periods of increasing annual precipitation.</p>

scholarly journals Study of factors influencing the encrustation of indwelling catheters: prospective case series

2021 ◽  
Vol 27 (1) ◽  
Author(s):  
Sanket Kalpande ◽  
P. R. Saravanan ◽  
K. Saravanan
Keyword(s):  
Case Series ◽  
Definitive Treatment ◽  
Physically Active ◽  
Indwelling Catheters ◽  
Factors Influencing ◽  
Culture Sensitivity ◽  
Calcium Phosphorus ◽  
Prospective Case Series ◽  
Active Patients

Abstract Background Long-term catheterisation is frequently necessary for patients with retention of urine or intractable incontinence who are unfit for definitive treatment or being evaluated for definitive treatment. In this study, the important factors influencing the encrustation of indwelling catheters are analysed. Methods A total of 52 patients on catheter drainage for a period ranging from 1 month to 1 year were taken in the study. Patients reported either for problems like catheter block or routine changing of catheter. The catheters were removed, and encrustation was subjected to chemical analysis. Urine was examined for pH, specific gravity, culture sensitivity and appearance. Blood samples were taken for estimation of calcium, phosphorus and uric acid. Results Out of 52 patients, 28 with urea splitting and 15 with non-urea splitting had positive urine culture (43 out of 52). Amongst 28, 27 (96%) had encrustation compared to 10 (50%) out of 15 with non-urea splitting bacteria (p value < .05). Amongst 24 patients having pH > 6, 22 (92%) had encrustation (p value < .05). The encrustation was found to be more common in bedridden patients (91%) when compared to physically active patients (54%) (p value < .05). The encrustation was more common in patients having single catheter for more than 15 days (86%) when compared to patients having catheter for shorter period (43%) (p value < .05). Conclusion This study showed definitive influence of the following factors in encrustation formation: infection with urea splitting organism, alkaline pH, physical activity of patient and duration of keeping a particular catheter.

scholarly journals The influence of density in population dynamics with strong and weak Allee effect

2021 ◽  
Vol 29 (1) ◽  
Author(s):  
Kamrun Nahar Keya ◽  
Md. Kamrujjaman ◽  
Md. Shafiqul Islam
Keyword(s):  
Population Dynamics ◽  
Allee Effect ◽  
Global Bifurcation ◽  
Reaction Diffusion ◽  
Logistic Growth ◽  
Allee Effects ◽  
Reaction Diffusion Model ◽  
Positive Steady States ◽  
The Stability ◽  
The Impact

AbstractIn this paper, we consider a reaction–diffusion model in population dynamics and study the impact of different types of Allee effects with logistic growth in the heterogeneous closed region. For strong Allee effects, usually, species unconditionally die out and an extinction-survival situation occurs when the effect is weak according to the resource and sparse functions. In particular, we study the impact of the multiplicative Allee effect in classical diffusion when the sparsity is either positive or negative. Negative sparsity implies a weak Allee effect, and the population survives in some domain and diverges otherwise. Positive sparsity gives a strong Allee effect, and the population extinct without any condition. The influence of Allee effects on the existence and persistence of positive steady states as well as global bifurcation diagrams is presented. The method of sub-super solutions is used for analyzing equations. The stability conditions and the region of positive solutions (multiple solutions may exist) are presented. When the diffusion is absent, we consider the model with and without harvesting, which are initial value problems (IVPs) and study the local stability analysis and present bifurcation analysis. We present a number of numerical examples to verify analytical results.

scholarly journals Acceptance and Intake of COVID-19 Vaccines among Older Germans

2021 ◽  
Vol 10 (7) ◽  
pp. 1388
Author(s):  
Marta Malesza ◽  
Erich Wittmann
Keyword(s):  
Side Effects ◽  
Long Term Effects ◽  
Negative Side ◽  
Factors Influencing ◽  
Vaccination Acceptance ◽  
Negative Side Effects

The main aim of this study was to investigate the various factors influencing COVID-19 vaccination acceptance and actual intake among older Germans aged over 75 years old (n = 1037). We found that the intention to get vaccinated or intake of the COVID-19 vaccine were positively related to the perceptions of becoming infected, perceptions of the severity of the potential long-term effects, the vaccine’s efficacy, and the benefits of vaccination. Meanwhile, the intention to get the vaccine or vaccine intake were decreased by perceptions of the negative side-effects and the general impediments to vaccination.

Long-term population dynamics of Dactylorhiza incarnata (L.) Soó after abandonment and re-introduction of mowing

Flora ◽  
2011 ◽  
Vol 206 (7) ◽  
pp. 622-630 ◽  
Author(s):  
Joachim Schrautzer ◽  
Andreas Fichtner ◽  
Aiko Huckauf ◽  
Leonid Rasran ◽  
Kai Jensen
Keyword(s):  
Population Dynamics

scholarly journals Increasing frequency of low summer precipitation synchronizes dynamics and compromises metapopulation stability in the Glanville fritillary butterfly

2015 ◽  
Vol 282 (1806) ◽  
pp. 20150173 ◽  
Author(s):  
Ayco J. M. Tack ◽  
Tommi Mononen ◽  
Ilkka Hanski
Keyword(s):  
Population Dynamics ◽  
Population Change ◽  
Temporal Dynamics ◽  
Summer Precipitation ◽  
Life History Stage ◽  
General Effect ◽  
Spatial Synchrony ◽  
Glanville Fritillary Butterfly ◽  
Spatio Temporal

Climate change is known to shift species' geographical ranges, phenologies and abundances, but less is known about other population dynamic consequences. Here, we analyse spatio-temporal dynamics of the Glanville fritillary butterfly ( Melitaea cinxia ) in a network of 4000 dry meadows during 21 years. The results demonstrate two strong, related patterns: the amplitude of year-to-year fluctuations in the size of the metapopulation as a whole has increased, though there is no long-term trend in average abundance; and there is a highly significant increase in the level of spatial synchrony in population dynamics. The increased synchrony cannot be explained by increasing within-year spatial correlation in precipitation, the key environmental driver of population change, or in per capita growth rate. On the other hand, the frequency of drought during a critical life-history stage (early larval instars) has increased over the years, which is sufficient to explain the increasing amplitude and the expanding spatial synchrony in metapopulation dynamics. Increased spatial synchrony has the general effect of reducing long-term metapopulation viability even if there is no change in average metapopulation size. This study demonstrates how temporal changes in weather conditions can lead to striking changes in spatio-temporal population dynamics.

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