selection variable
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2021 ◽  
Author(s):  
C. Keating ◽  
M. Bolton-Warberg ◽  
J. Hinchcliffe ◽  
R. Davies ◽  
S. Whelan ◽  
...  

AbstractThe microbiota in the gastrointestinal tract of any species is shaped by internal and external cues in addition to random events which can be difficult to disentangle from a range of interacting variables. Estimating ecological assembly processes can help elucidate these factors. In our study, farmed Atlantic cod (Gadus morhua) were fed a diet of 10% macroalgae supplement (Ulva rigida species [ULVA] or Ascophyllum nodosum [ASCO] or a non-amended control diet [CTRL]) over a 12-week period and the ecological assembly processes quantified. The CTRL samples showed selection (variable selection - divergence in communities related to selective environmental conditions) as a key assembly process, while dispersal limitation (limited movement results in divergent communities through stochastic processes) was a driver of the gut microbiome for fish fed the macroalgae supplemented diet at Week 12 (i.e., ASCO and ULVA). Fish from the ASCO grouping diverged into ASCO_N (normal) and ASCO_LG (lower growth), where ASCO_LG individuals found the diet unpalatable. The recruitment of new taxa over time was altered in the ASCO_LG fish, with the gut microbiome showing phylogenetic under dispersion (nepotistic recruitment of species). Finally, the gut microbiome (CTRL and ULVA only) showed increasing robustness to taxonomic disturbance over time and an increase in functional redundancy. This study advances our understanding of the ecological assembly and succession in the hindgut of juvenile Atlantic cod across dietary regimes. Understanding the processes driving ecological assembly in the gut microbiome, in fish research specifically, could allow us to manipulate the microbiome for improved health or resilience to disease for improved aquaculture production.



2021 ◽  
pp. 1-16
Author(s):  
Huili Pei ◽  
Hongliang Li ◽  
Yankui Liu

In practical decision-making problems, decision makers are often affected by uncertain parameters because the exact distributions of uncertain parameters are usually difficult to determine. In order to deal with this issue, the major contribution in this paper is to propose a new type of type-2 fuzzy variable called level interval type-2 fuzzy variable from the perspective of level-sets, which is a useful tool in modeling distribution uncertainty. With our level interval type-2 fuzzy variable, we give a method for constructing a parametric level interval (PLI) type-2 fuzzy variable from a nominal possibility distribution by introducing the horizontal perturbation parameters. The proposed horizontal perturbation around the nominal distribution is different from the vertical perturbation discussed in the literature. In order to facilitate the modeling in practical decision-making problems, for a level interval type-2 fuzzy variable, we define its selection variable whose distribution can be determined via its level-sets. The numerical characteristics like expected value and second order moments are important indices in practical optimization and decision-making problems. With this consideration, we establish the analytical expressions about the expected values and second order moments of the selection variables of PLI type-2 trapezoidal, normal and log-normal fuzzy variables. Furthermore, in order to derive the analytical expressions about the numerical characteristics of the selection variable for the sums of the common PLI type-2 fuzzy variables, we discuss the arithmetic about the sums of common PLI type-2 fuzzy variables. Finally, we apply the proposed optimization method to a pricing decision problem to demonstrate the efficiency of our new method. The computational results show that even a small perturbation of the nominal possibility distribution can affect the quality of solutions.



Author(s):  
Todd Mitton

Abstract I document large variation in empirical methodology in corporate finance regressions in top finance journals. Although methodological variation allows for customization of empirical tests to fit specific theories, it can also enable excessive reporting of statistically significant results. For example, given discretion over 10 routine methodological decisions, a researcher could report that over 70% of randomly generated variables are statistically significant determinants of leverage at the 5% level. The methodological decisions that affect statistical significance the most are dependent variable selection, variable transformation, and outlier treatment. I discuss remedies that can mitigate the negative effects of methodological variation.



PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10917
Author(s):  
Alfred Ngwira ◽  
Francisco Chamera ◽  
Matrina Mpeketula Soko

Background Estimation of prevalence of feeding practices during diarrhea using conventional imputation methods may be biased as these methods apply to observed factors and in this study, feeding practice status was unobserved for those without diarrhea. The study aimed at re-estimating the prevalence of feeding practices using the bivariate sample selection model. Methods The study used 2015–2016 Malawi demographic health survey (MDHS) data which had 16,246 children records who had diarrhea or not. A bivariate Joe copula regression model with 90 degrees rotation was fitted to either drinking or eating more, with diarrhea as a sample selection outcome in the bivariate models. The prevalence of drinking more than usual and prevalence of eating more than usual were then estimated based on the fitted bivariate model. These prevalences were then compared to the prevalences estimated using the conventional imputation method. Results There was a substantial increase in the re-estimated national prevalence of drinking more fluids (40.0%, 95% CI [31.7–50.5]) or prevalence of eating more food (20.46%, 95% CI [9.87–38.55]) using the bivariate model as compared to the prevalences estimated by the conventional imputation method, that is, (28.9%, 95% CI [27.0–30.7]) and (13.1%, 95% CI [12.0–15.0]) respectively. The maps of the regional prevalences showed similar results where the prevalences estimated by the bivariate model were relatively higher than those estimated by the standard imputation method. The presence of diarrhea was somehow weakly negatively correlated with either drinking more fluids or eating more food. Conclusion The estimation of prevalence of drinking more fluids or eating more food during diarrhea should use bivariate modelling to model sample selection variable so as to minimize bias. The observed negative correlation between diarrhea presence and feeding practices implies that mothers should be encouraged to let their children drink more fluids or eat more food during diarrhea episode to avoid dehydration and malnutrition.



2020 ◽  
Vol 2 (1) ◽  
pp. 65-84
Author(s):  
Syafrizal Al-Fatih ◽  
Pinondang Nainggolan ◽  
Resna Napitu

ABSTRAK  PENGARUH REKRUTMEN DAN SELEKSI TERHADAP KINERJA KARYAWAN PADA PD. SINARMAS PEMATANGSIANTAR  Tujuan dari penelitian ini adalah untuk mengetahui seberapa besar pengaruh proses rekrutmen dan seleksi terhadap kinerja pegawai pada PD. Sinarmas Pematangsiantar. Data yang digunakan dalam penelitian ini adalah data primer dan data sekunder. Data primer adalah data yang diolah dari hasil pengisian kuesioner yang telah diedarkan ke seluruh karyawan, dalam hal ini pimpinan cabang pada PD. Sinarmas Pematangsiantar dan staf perusahaan yang berjumlah 32 orang mulai dari administrasi, marketing dan kolektor yang sesuai dengan kebutuhan dalam penelitian ini. Sedangkan data sekunder diperoleh dari sumber data yang diperoleh dengan cara membaca, mempelajari dan memahami melalui media lain yang bersumber dari literatur dan buku-buku. Hasil penelitian ini menunjukkan bahwa rekrutmen dan seleksi dalam uji hipotesis secara parsial (uji t) bahwa variabel rekrutmen (X1) berpengaruh signifikan terhadap kinerja karyawan (Y) dimana thitung > ttabel dan signifikan 0,001 < 0,05, begitu juga dengan variabel seleksi (X2) berpengaruh signifikan terhadap kinerja karyawan (Y) dimana thitung > ttabel dan signifikan 0,025 < 0,05. Selanjutnya dengan uji bersama (uji F) bahwa secara bersama variabel rekrutmen (X1) dan seleksi (X2) berpengaruh signifikan terhadap kinerja karyawan (Y) dengan Fhitung > Ftabel atau signifikan 0,000 < 0,05. Dalam uji determinasi (R2) menyatakan bahwa variabel rekrutmen dan seleksi mempengaruhi variabel kinerja karyawan sebesar 71,4%. Kata Kunci: Rekrutmen, Seleksi, Kinerja Karyawan.   ABSTRACT  EFFECT OF RECRUITMENT AND SELECTION ON EMPLOYEE PERFORMANCE IN PD. SINARMAS PEMATANGSIANTAR  The purpose of this study was to determine how much influence the recruitment and selection process on employee performance in PD. Sinarmas Pematangsiantar. The data used in this study are primary data and secondary data. Primary data is data that is processed from the results of filling out a questionnaire that has been circulated to all employees, in this case the branch leadership at PD. Sinarmas Pematangsiantar and company staff totaling 32 people ranging from administration, marketing and collectors according to the needs in this study. While secondary data obtained from data sources obtained by reading, studying and understanding through other media sourced from literature and books. The results of this study indicate that recruitment and selection in the partial hypothesis test (t test) that the recruitment variable (X1) has a significant effect on employee performance (Y) where tcount > ttable and significant 0.001 < 0.05, as well as the selection variable (X2 ) significantly influence employee performance (Y) where tcount > ttable and significant 0.025 < 0.05. Furthermore, with the joint test (F test) that the recruitment variable (X1) and selection (X2) together had a significant effect on employee performance (Y) with Fcount> Ftable or significant 0,000 < 0.05. In the determination test (R2) states that the recruitment and selection variables affect employee performance variables by 71.4%. Keywords: Recruitment, Selection, Employee Performance.



2020 ◽  
Vol 3 (1) ◽  
pp. 66-82
Author(s):  
Veritia Veritia ◽  
Daning Daning

This study aims to find out positively and significantly the effect of recruitment on employee performance, the effect of selection on employee performance, and the effect of joint recruitment and selection on employee performance. The method used in this research is quantitative descriptive which explains correlational relationships. The population and samples studied were employees of PT. Trinitas Mulia Abadi North Jakarta as many as 85 people using saturated samples because they are less than 100. In the multiple linear regression test the equation is Y = 14,098 + 0,364X1 + 0,282X2 which means that the recruitment and selection variables are in line with employee performance and have a positive effect. Partial significance test results for the recruitment variable (X1) obtained t count> t table or (6,481> 1,989) with a significance value (0,000 <0,05), while the selection variable (X2) obtained tcount> t table or (5,852> 1,989) with a significance value (0,000 <0,05) thus the correlation between X and Y is positive and significant. And simultaneous testing between X1 and X2 towards Y is obtained by the value of Fcount> Ftable or (28,745> 3,110) which is strengthened by a significance probability value of 0,000 <0,5 so there is a positive and significant effect simultaneously between X1 and X2 towards Y. Abstrak Penelitian ini bertujuan untuk mengetahui secara positif dan signifikan pengaruh rekrutmen terhadap kinerja karyawan, pengaruh seleksi terhadap kinerja karyawan, dan pengaruh rekrutmen dan seleksi secara bersama-sama terhadap kinerja karyawan. Metode yang digunakan dalam penelitian ini adalah kuantitatif deskriptif yang menjelaskan hubungan korelasional. Populasi dan sampel yang diteliti adalah karyawan PT. Trinitas Mulia Abadi Jakarta Utara sebanyak 85 orang dengan menggunakan sampel jenuh karena kurang dari 100. Pada uji regresi linier berganda yang dihasilkan persamaan yaitu Y = 14,098 + 0,364X1 + 0,282X2 yang artinya variabel rekrutmen dan seleksi searah dengan kinerja karyawan dan berpengaruh secara positif. Hasil uji signifikansi secara parsial untuk variabel rekrutmen (X1) diperoleh nilai t hitung > ttabel atau (6,481 > 1,989) dengan nilai signifikansi (0,000 < 0,05), sedangkan untuk variabel seleksi (X2) diperoleh nilai thitung > ttabel atau (5,852 > 1,989) dengan nilai signifikansi (0,000 < 0,05) dengan demikian korelasi antara X terhadap Y adalah positif dan signifikan. Dan pengujian secara simultan antara X1 dan X2 terhadap Y diperoleh nilai Fhitung > Ftabel atau (28,745 > 3,110) yang diperkuat dengan nilai probability signifikansi sebesar 0,000 < 0,5 maka terdapat pengaruh yang positif dan signifikan secara simultan antara X1 dan X2 terhadap Y.



Author(s):  
Alayya Maghfiroh ◽  
Sulis Riptiono

This study aims to analyze the effect of variety of selection to web browsing and e- impulse buying for consumer Bukalapak in Kebumen Regency. Variable independent in this study variety of selection, variable dependent e-impulse buying, and variable intervening web browsing. This study confirm two types of web browsing occur: utilitarian browsing and hedonic browsing. Consumer Bukalapak in Kebumen Regency completed a total 100 questionnaires using Google Form. Data analyze was conducted using Path analysis and SPSS 22.0. In a structural model, variety of selection has a possitive effect on utilitarian browsing and hedonic browsing. Additionally, utilitarian browsing has a negative effect on e-impulse buying. In particular, the factor variety of selection haven’t direct effect on e-impulse buying, but have indirect effect to e-impulse buying with mediate hedonic browsing.



2019 ◽  
Vol 111 (11) ◽  
pp. 1142-1151 ◽  
Author(s):  
Sebastian E Baumeister ◽  
Michael F Leitzmann ◽  
Jakob Linseisen ◽  
Sabrina Schlesinger

Abstract Background Physical inactivity is an established risk factor for several cancers of the digestive system and female reproductive organs, but the evidence for liver cancers is less conclusive. Methods The aim of this study was to synthesize prospective observational studies on the association of physical activity and liver cancer risk by means of a systematic review and meta-analysis. We searched Medline, Embase, and Scopus from inception to January 2019 for prospective studies investigating the association of physical activity and liver cancer risk. We calculated mean hazard ratios (HRs) and 95% confidence intervals (CIs) using a random-effects model. We quantified the extent to which an unmeasured confounder or an unaccounted selection variable could shift the mean hazard ratio to the null. Results Fourteen prospective studies, including 6,440 liver cancers, were included in the systematic review and meta-analysis. The mean hazard ratio for high compared with low physical activity was 0.75 (95% CI = 0.63 to 0.89; 95% prediction interval = 0.52 to 1.07; I² = 64.2%). We estimated that 67.6% (95% CI = 56.6% to 78.5%) of all true effect estimates would have a hazard ratio less than 0.8. Bias analysis suggested than an unobserved confounder would have to be associated with a 1.99-fold increase in the risk of physical activity or liver cancer to explain away the observed mean hazard ratio. An unaccounted for selection variable would have to be related to exposure and endpoint with a relative risk of 1.58 to explain away the mean hazard ratio. Conclusions Physical activity is inversely related to the risk of liver cancer. Further studies with objectively measured physical activity and quasi-experimental designs addressing confounding are needed.



Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-16
Author(s):  
Bo Zhang ◽  
YuHua Cheng ◽  
Chun Yin ◽  
Xuegang Huang ◽  
Sara Dadras ◽  
...  

In this paper, in order to achieve automatic defect identification for pneumatic pressure equipment, an improved feature extraction algorithm eddy current pulsed thermography (ECPT) is presented. The presented feature extraction algorithm contains four elements: data block selection; variable step search; relation value classification; and between-class distance decision function. The data block selection and variable step search are integrated to decrease the redundant computations in the automatic defect identification. The goal of the classification and between-class distance calculation is to select the typical features of thermographic sequence. The main image information can be extracted by the method precisely and efficiently. Experimental results are provided to demonstrate the capabilities and benefits (i.e., reducing the processing time) of the proposed algorithm in automatic defect identification.



2018 ◽  
Author(s):  
Arne Jacobs ◽  
Madeleine Carruthers ◽  
Andrey Yurchenko ◽  
Natalia V. Gordeeva ◽  
Sergei S. Alekseyev ◽  
...  

AbstractUnderstanding the extent to which evolution is predictable under multifarious selection is a longstanding question in evolutionary biology. However, the interplay of stochastic and contingent factors influencing the extent of parallelism in nature is not well understood. To test the predictability of evolution, we studied a ‘natural experiment’ on different organismal levels across lakes and evolutionary lineages of a freshwater salmonid fish, Arctic charr (Salvelinus alpinus). We identified significant phenotypic parallelism between Arctic charr ecotype pairs within a continuum of parallel evolution and highly parallel adaptive morphological traits. Variability in phenotypic predictability was explained by complex demographic histories, differing genomic backgrounds and genomic responses to selection, variable genetic associations with ecotype, and environmental variation. Remarkably, gene expression was highly similar across ecotype replicates, and explained the observed parallelism continuum. Our findings suggest that parallel evolution by non-parallel evolutionary routes is possible when the regulatory molecular phenotype compensates for divergent histories.



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