scholarly journals A population of sexual Daphnia pulex resists invasion by asexual clones

2014 ◽  
Vol 281 (1788) ◽  
pp. 20140564 ◽  
Author(s):  
David J. Innes ◽  
Michael Ginn
Keyword(s):  
Daphnia Pulex ◽  
Low Frequency ◽  
Population Bottlenecks ◽  
Short Term ◽  
Sexual Population ◽  
Factors Affecting ◽  
Egg Bank ◽  
Diapausing Eggs ◽  
Rare Males ◽  
Negative Factors

Asexual reproduction avoids the costs associated with sex, predicting that invading asexual clones can quickly replace sexual populations. Daphnia pulex populations in the Great Lakes area are predominately asexual, but the elimination of sexual populations by invading clones is poorly understood. Asexual clones were detected at low frequency in one rare sexual population in 1995, with some increase in frequency during 2003 and 2004. However, these clones remained at low frequency during further yearly sampling (2005–2013) with no evidence that the resident sexual population was in danger of elimination. There was evidence for hybridization between rare males produced by asexual clones and sexual females with the potential to produce new asexual genotypes and spread the genetic factors for asexuality. In a short-term laboratory competition experiment, the two most common asexual clones did not increase in frequency relative to a genetically diverse sexual population due in part to a greater investment in diapausing eggs that trades-off current population growth for increased contribution to the egg bank. Our results suggest that a successful invasion can be prolonged, requiring a combination of clonal genotypes with high fitness, persistence of clones in the egg bank and negative factors affecting the sexual population such as inbreeding depression resulting from population bottlenecks.

DIRECTIONS FOR DEVELOPMENT OF ANTI-CRISIS FINANCIAL MANAGEMENT

2017 ◽  
Author(s):  
Liubov Iarova ◽  
Keyword(s):  
Financial Management ◽  
Financial Stability ◽  
Enterprise Management ◽  
Factors Affecting ◽  
Financial Condition ◽  
Flexible Response ◽  
Relevant Topic ◽  
Potential Risks ◽  
Negative Factors ◽  
Theoretical Foundations

For continuous performance, enterprises should not only take into account potential risks and existing negative factors, but also develop methods and principles that allow timely and flexible response to crisis occurrences, as well as determine the recovery stages in an already deteriorated financial condition. Given tasks are solved by anti-crisis financial management, designed to increase the efficiency of enterprise management and facilitate the equalization or improvement of an economic entity’s financial stability, therefore, the directions of its development are a rather relevant topic in a market economy. The article examines the theoretical foundations of anti-crisis financial management, the main factors affecting the emergence of a crisis state at an enterprise, discusses the need for its development, and provides factors that determine the effectiveness of the implemented anti-crisis policy. Identifying the need to improve anti-crisis financial management and decision-making on its implementation are accompanied by an analysis that takes into consideration possible risks and costs, which determines the expected effect. The author generalizes and indicates the main principles and stages of anti- crisis management.

SIMULATION OF SOFT START OF SYNCHRONOUS ELECTRIC DRIVES

2019 ◽  
Author(s):  
Shakhboz Dadabaev
Keyword(s):  
Computer Simulation ◽  
Electric Drive ◽  
Water Supply Systems ◽  
Factors Affecting ◽  
Electric Drives ◽  
Soft Start ◽  
Simulation Results ◽  
Pumping Units ◽  
Negative Factors ◽  
Supply Systems

The main negative factors affecting the starting modes of synchronous electric drives of pumping units of irrigation water supply systems were identified, computer simulation of direct and soft start of synchronous electric drive was made, the simulation results are shown in graphs and a brief conclusion was made on the study.

scholarly journals Analyzing Factors Affecting the Sustainability of Land Management Practices in Mecha Woreda, Northwestern Ethiopia

2021 ◽  
Vol 13 (13) ◽  
pp. 7007
Author(s):  
Habtamu Nebere ◽  
Degefa Tolossa ◽  
Amare Bantider
Keyword(s):  
Decision Making ◽  
Land Management ◽  
Land Degradation ◽  
Quantitative Data ◽  
Management Practices ◽  
Short Term ◽  
Factors Affecting ◽  
Decision Making Processes ◽  
Household Heads ◽  
The Impact

In Ethiopia, the practice of land management started three decades ago in order to address the problem of land degradation and to further boost agricultural production. However, the impact of land management practices in curbing land degradation problems and improving the productivity of the agricultural sector is insignificant. Various empirical works have previously identified the determinants of the adoption rate of land management practices. However, the sustainability of land management practices after adoption, and the various factors that control the sustainability of implemented land management practices, are not well addressed. This study analyzed the factors affecting the sustainability of land management practices after implementation in Mecha Woreda, northwestern Ethiopia. The study used 378 sample respondents, selected by a systematic random sampling technique. Binary logistic regression was used to analyze the quantitative data, while the qualitative data were qualitatively and concurrently analyzed with the quantitative data. The sustained supply of fodder from the implemented land management practices, as well as improved cattle breed, increases the sustainability of the implemented land management practices. While lack of agreement in the community, lack of enforcing community bylaws, open cattle grazing, lack of benefits of implemented land management practices, acting as barrier for farming practices, poor participation of household heads during planning and decision-making processes, as well as the lack of short-term benefits, reduce the sustainability of the implemented land management practices. Thus, it is better to allow for the full participation of household heads in planning and decision-making processes to bring practical and visible results in land management practices. In addition, recognizing short-term benefits to compensate the land lost in constructing land management structures must be the strategy in land management practices. Finally, reducing the number of cattle and practicing stall feeding is helpful both for the sustainability of land management practices and the productivity of cattle. In line with this, fast-growing fodder grass species have to be introduced for household heads to grow on land management structures and communal grazing fields for stall feeding.

scholarly journals Small Floating Target Detection Method Based on Chaotic Long Short-Term Memory Network

2021 ◽  
Vol 9 (6) ◽  
pp. 651
Author(s):  
Yan Yan ◽  
Hongyan Xing
Keyword(s):  
High Frequency ◽  
Short Term Memory ◽  
Detection Method ◽  
Low Frequency ◽  
Sea Clutter ◽  
Short Term ◽  
Term Memory ◽  
Memory Network ◽  
Long Short Term Memory ◽  
Small Targets

In order for the detection ability of floating small targets in sea clutter to be improved, on the basis of the complete ensemble empirical mode decomposition (CEEMD) algorithm, the high-frequency parts and low-frequency parts are determined by the energy proportion of the intrinsic mode function (IMF); the high-frequency part is denoised by wavelet packet transform (WPT), whereas the denoised high-frequency IMFs and low-frequency IMFs reconstruct the pure sea clutter signal together. According to the chaotic characteristics of sea clutter, we proposed an adaptive training timesteps strategy. The training timesteps of network were determined by the width of embedded window, and the chaotic long short-term memory network detection was designed. The sea clutter signals after denoising were predicted by chaotic long short-term memory (LSTM) network, and small target signals were detected from the prediction errors. The experimental results showed that the CEEMD-WPT algorithm was consistent with the target distribution characteristics of sea clutter, and the denoising performance was improved by 33.6% on average. The proposed chaotic long- and short-term memory network, which determines the training step length according to the width of embedded window, is a new detection method that can accurately detect small targets submerged in the background of sea clutter.

Factors Affecting the Learning of Foreign Language Vocabulary: Imagery Keyword Mediators and Phonological Short-Term Memory

1993 ◽  
Vol 46 (3) ◽  
pp. 533-558 ◽  
Author(s):  
Nick Ellis ◽  
Alan Beaton
Keyword(s):  
Theoretical Analysis ◽  
Foreign Language ◽  
Cognitive Processes ◽  
Short Term Memory ◽  
Vocabulary Learning ◽  
Short Term ◽  
Term Memory ◽  
Factors Affecting ◽  
Foreign Word ◽  
Lexical Factors

In order to investigate the cognitive processes involved in learning Foreign Language (FL) vocabulary, this study evaluates different methods of instruction. It demonstrates that keyword techniques are effective for receptive learning but that repetition is a superior strategy for learning to produce the foreign word. Performance is optimal when learners combine both strategies. The nature of the keyword is crucial–-whereas imageable noun keywords promote learning, verb keywords actually impede it. A theoretical analysis of the roles of phonological short-term memory, imagery, and lexical factors in FL vocabulary learning is presented.

HEART RATE VARIABILITY RELATED TO N95 RESPIRATOR USE IN INTERNS DURING COVID-19 PANDEMIC

2021 ◽  
pp. 69-70
Author(s):  
Pakanati Sujana ◽  
Venkata Mahesh Gandhavalla ◽  
K. Prabhakara Rao
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Low Frequency ◽  
Protective Equipment ◽  
Short Term ◽  
Non Invasive ◽  
Critical Components ◽  
The Individual ◽  
N95 Respirators ◽  
Respiratory Droplets

Introduction: COVID19 is caused by SARS-CoV-2 which is primarily transmitted through respiratory droplets and contact routes. WHO recommended the use of personal protective equipment (PPE) for prevention and N95 respirators are critical components of PPE. Breathing through N95 respirator will impart stress in the individual and that can be assessed by heart rate variability (HRV). HRV measures the variation in time between each heartbeat controlled by autonomic nervous system (ANS), which is a non invasive reliable index to identify the ANS imbalances. Aims And Objectives: This study is aimed at assessing the HRV of Interns working in COVID19 wards using N95 respirators. Methodology: This study included 100 interns in whom short term HRV was recorded using the standard protocol. Lead II of ECG was recorded using AD instruments (ADI) 8channel polygraph and HRV was analysed using Labchart 8pro software. The recordings were taken before and 1hour after wearing N95 respirator. Results: Overall HRV (SDRR) was found to decrease signicantly after wearing N95 respirator for 1hr (p=0.000). Similarly, indices representing the parasympathetic component ( RMSSD and HF ) were also found to decrease signicantly with the use of N95 respirator. Low frequency (LF) power and LF/HF ratio increased signicantly with N95 respirator use (p=0.000). Conclusion: We conclude that using N95 respirator increased sympathetic activity reecting decreased HRV in our subjects Hence we recommend that it is better to change the duty pattern for interns.

scholarly journals Changes in the ultra-low frequency wave field during the precursor phase to the Sichuan earthquake: DEMETER observations

2013 ◽  
Vol 31 (9) ◽  
pp. 1597-1603 ◽  
Author(s):  
S. N. Walker ◽  
V. Kadirkamanathan ◽  
O. A. Pokhotelov
Keyword(s):  
Low Frequency ◽  
Large Earthquake ◽  
Short Term ◽  
Frequency Wave ◽  
Sichuan Earthquake ◽  
Ulf Wave ◽  
Precursor Phase ◽  
Demeter Satellite ◽  
Short Term Prediction ◽  
Atmospheric Gravity

Abstract. Electromagnetic phenomena observed in association with increases in seismic activity have been studied for several decades. These phenomena are generated during the precursory phases of an earthquake as well as during the main event. Their occurrence during the precursory phases may be used in short-term prediction of a large earthquake. In this paper, we examine ultra-low frequency (ULF) electric field data from the DEMETER satellite during the period leading up to the Sichuan earthquake. It is shown that there is an increase in ULF wave activity observed as DEMETER passes in the vicinity of the earthquake epicentre. This increase is most obvious at lower frequencies. Examination of the ULF spectra shows the possible occurrence of geomagnetic pearl pulsations, resulting from the passage of atmospheric gravity waves generated in the vicinity of the earthquake epicentre.

Sign in / Sign up

Export Citation Format

Share Document