frequency effect
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Genetics ◽  
2022 ◽  
Vol 220 (1) ◽  
Author(s):  
Sam Yeaman

Abstract Observations about the number, frequency, effect size, and genomic distribution of alleles associated with complex traits must be interpreted in light of evolutionary process. These characteristics, which constitute a trait’s genetic architecture, can dramatically affect evolutionary outcomes in applications from agriculture to medicine, and can provide a window into how evolution works. Here, I review theoretical predictions about the evolution of genetic architecture under spatially homogeneous, global adaptation as compared with spatially heterogeneous, local adaptation. Due to the tension between divergent selection and migration, local adaptation can favor “concentrated” genetic architectures that are enriched for alleles of larger effect, clustered in a smaller number of genomic regions, relative to expectations under global adaptation. However, the evolution of such architectures may be limited by many factors, including the genotypic redundancy of the trait, mutation rate, and temporal variability of environment. I review the circumstances in which predictions differ for global vs local adaptation and discuss where progress can be made in testing hypotheses using data from natural populations and lab experiments. As the field of comparative population genomics expands in scope, differences in architecture among traits and species will provide insights into how evolution works, and such differences must be interpreted in light of which kind of selection has been operating.


2021 ◽  
Vol 15 (2) ◽  
pp. 154
Author(s):  
Herliati Rahman ◽  
Satrio Nur Pambudi ◽  
Wahyu Endrunaka

Gingerol is a chemical compound found in red ginger, with pharmaceutical use as an analgesic drug. Generally, gingerol separation in ginger uses the Soxhlet extraction method, but this process has a weakness. It requires a long process and unsatisfactory yield. This research aims to study ultrasonic frequency effect on increasing gingerol yield in the extraction process. The variables studied were extraction times with variations of 30, 60, 90, and 120 minutes. In addition, the ultrasonic effect was also observed with variations in the ultrasonic frequency of 40 and 50 kHz compared to the solvent extraction method. This study used 70% (v/v) ethanol as a solvent and an operating temperature of 50 ºC as fixed variables.Furthermore, it used a rotary vacuum evaporator at a pressure of 350 mmHg to separate the resulting gingerol extract. Qualitative sample analysis used Thin Layer Chromatography (TLC) and scanning electron microscope (SEM) while quantitative analysis used high-performance liquid chromatography (HPLC), Waters Alliance e2695 brand with X-Terra RP18 column 100 x 4.6 mm, five μm to determine the total gingerol extract. The results showed that ultrasonic power had a significant effect on the results obtained, with the highest yield was 24.71% at the ultrasonic frequency of 50 kHz with an extraction time of 120 minutes.


2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Lan Xu

Background. English is one of the courses offered in all colleges and universities. The quality of English teaching is directly related to the quality of talent training and the development of students themselves. “Teaching quality evaluation” specifically refers to the education evaluation with teaching as the evaluation object. It is the core and foundation of the whole education evaluation. Teaching quality evaluation is based on certain teaching objectives and teaching norms and standards, through the systematic detection and assessment of teaching and learning. Evaluate its teaching effect and the degree of realization of teaching objectives, and use scientific and feasible methods to make corresponding value judgments to improve the process of teaching. To improve the accuracy of English teaching ability evaluation, an English teaching ability evaluation algorithm based on frequency effect is proposed. Methods. The paper proposes an English teaching ability evaluation algorithm based on frequency effect. Firstly, it constructs the evaluation index system of English teaching ability, including expert evaluation system, student evaluation system, and teacher evaluation system. Then, the indexes affecting the evaluation of English teaching ability are quantified by fuzzy synthesis, and the evaluation indexes are refined. Finally, the basic principle of frequency effect is analyzed, combined with the convolutional neural network. Results. The convolutional neural network evaluation model is constructed, the teaching ability indicators are input into the model, the final evaluation results are output, and the design of the English teaching ability evaluation algorithm based on frequency effect is completed. Conclusions. The experimental results show that this method has high accuracy and efficiency.


2021 ◽  
Vol 2 ◽  
pp. 4
Author(s):  
Bouhadjar Meriem ◽  
Halim Zeghdoudi ◽  
Abdelali Ezzebsa

The main purpose of this paper is to introduce and investigate stochastic orders of scalar products of random vectors. We study the problem of finding maximal expected utility for some functional on insurance portfolios involving some additional (independent) randomization. Furthermore, applications in policy limits and deductible are obtained, we consider the scalar product of two random vectors which separates the severity effect and the frequency effect in the study of the optimal allocation of policy limits and deductibles. In that respect, we obtain the ordering of the optimal allocation of policy limits and deductibles when the dependence structure of the losses is unknown. Our application is a further study of [1 − 6].


2021 ◽  
Vol 10 (21) ◽  
pp. 5175
Author(s):  
Yi-Hsien Chen ◽  
Yun-Yi Chen ◽  
Yu-Wei Fang ◽  
Ming-Hsien Tsai

Chronic kidney disease (CKD) is associated with dementia. Angiotensin receptor blockers (ARBs) have been widely used for delaying CKD progression; however, their effect on dementia prevention in patients with CKD remains unclear. We designed a retrospective cohort study to investigate the effects of ARBs on the incidence of dementia in patients with CKD. We selected 21,208 patients from the Taiwan nationwide database from 1 January 2006 to 31 December 2006. We identified ARB users (n = 17,466) and ARB non-users (n = 3742) and their medication possession ratio (MPR). The Cox proportional hazard model was used to estimate hazard ratios (HRs) for the incidence of dementia in ARB users in the CKD population. During the 11-year follow-up period, 2207 dementia events were recorded; multivariate-adjusted hazard ratios for dementia by ARB usage and ARB usage per MPR were 0.578 (95% CI: 0.52–0.643) and 0.996 (95% CI: 0.995–0.998), respectively. This association was observed in almost all subgroups. Dose frequency effect of ARBs was noted; patients with higher MPRs of ARBs generally had higher protection from dementia. Patients with hypertension and CKD who received ARBs had a decreased risk of dementia. Protective effects of ARBs on dementia increased with the frequency of ARB use.


2021 ◽  
Vol 76 (4) ◽  
pp. 368-376
Author(s):  
Aleksandr V. Zubko ◽  
Tamara P. Sabgayda ◽  
Alla E. Ivanova ◽  
Galina N. Evdokushkina ◽  
Vyacheslav G. Zaporozhchenko ◽  
...  

Background.Comorbidity of diseases deteriorates health and often increases the risk of death. Identification of comorbidities with diseases of the circulatory system (DCS) will help find additional measures to increase life expectancy. Aims to identify causes associated with death from DCS and to analyze their interrelation based on the multiple cause analysis. Materials and methods.Data on DCS deaths of the Death registration in the Moscow Unified Medical Information and Analytical System (RFS-EMIAS) in 2019 (46 000 deaths) and from April to May 2020 (11 000 deaths) excluding perinatal mortality were analyzed. The association analysis was carried out across groups of the ICD-10 DCS blocks by calculating the corresponding frequency. Effect of SARS-CoV-2 was analyzed in the infected deceased and those free from infection. Comparison was carried out by the Chi-square test. Results.The following Diseases of the circulatory system are associated with Diabetes mellitus: Hypertension, Coronary heart disease, Cerebrovascular diseases, and Diseases of arteries, arterioles and capillaries. A synergetic effect has been identified in comorbidity with the diseases characterized by high blood pressure and Chronic rheumatic heart diseases, other forms of heart disease(I30I52), Cerebrovascular diseases and Diseases of arteries, arterioles and capillaries; the latter and Coronary heart disease and Cerebrovascular diseases; other forms of heart disease and Mental disorders due to psychoactive substance use; Diseases of veins, lymphatic vessels and lymph nodes and Pulmonary circulation disorders. Effect of the increased risk of death in non-symmetric associations of causes has been detected for comorbidity of Diseases of veins, lymph vessels and lymph nodes and Chronic viral hepatitis; Coronary heart disease and other forms of heart disease; Hypertension and Coronary heart disease; in males comorbidity of Obesity and Hypertension, and Diseases of arteries, arterioles and capillaries and Hypertension. Associations between DCS and their complications have been identified in females: Diseases of veins, lymph vessels and lymph nodes and Phlegmon, and Cerebrovascular diseases and Decubital ulcers. Conclusion.SARS-CoV-2 increases mortality from Chronic coronary heart disease, ICD-10 I67.8 code for Other specified cerebrovascular diseases and Hypertension in females 1.5-fold. The infection rate in females died from DCS is significantly lower compared to the one in males.


2021 ◽  
Author(s):  
Brad McKay ◽  
Julia Hussien ◽  
Mary-Anne Vinh ◽  
Alexandre Mir-Orefice ◽  
Hugh Brooks ◽  
...  

A fundamental motor learning principle conveyed in textbooks is that augmented terminal feedback frequency differentially affects motor learning and performance. The guidance hypothesis predicts that relative to a reduced frequency of feedback, providing learners with feedback following every practice trial enhances practice performance but degrades subsequent motor learning. This change in effectiveness for each relative feedback frequency is called a reversal effect, and because it is thought that practice variables can have distinct impacts on learning and performance, delayed retention tests are considered the gold standard in motor learning research. The objectives of this meta-analysis were to a) synthesize the available evidence regarding feedback frequency, performance, and motor learning to test whether there are significant changes in effectiveness from acquisition and immediate retention to delayed retention, b) evaluate potential moderators of these effects, and c) investigate the potential influence of publication bias on this literature. We screened 1662 articles found in PubMed and PsycINFO databases as well as with reference tracing and a targeted author search. A final sample of 61 eligible papers were included in the primary analysis (k = 75, N = 2228). Results revealed substantial heterogeneity but no significant moderators, high levels of uncertainty, and no significant effect of reduced feedback frequency at any time point. Further, multilevel analyses revealed no evidence of a significant change in effect from acquisition or immediate retention to delayed retention. Z-curve analysis suggested the included studies were severely underpowered. These results suggest that robust evidence regarding feedback frequency and motor learning is lacking.


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