maximum likelihood method
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2023 ◽  
Vol 83 ◽  
Author(s):  
B. M. Khan ◽  
M. Sabir ◽  
M. N. Alyemeni ◽  
P. Kaushik ◽  
M. Saeed ◽  
...  

Abstract This study aimed to identify the phylogenetic similarities among the muntjac (Muntiacus spp.). The phylogenetic similarities among seven major muntjac species were studied by comparing the nucleotide sequence of 16s rRNA and cytochrome b genome. Nucleotide sequences, retrieved from NCBI databases were aligned by using DNASTAR software. A phylogenetic tree was created for the selected species of muntjac by using the maximum likelihood method on MEGA7 software. The results of nucleotide sequences (16s rRNA) showed phylogenetic similarities between, the M. truongsonensis and M. rooseveltorum had the highest (99.2%) while the lowest similarities (96.8%) found between M. crinifrons and M. putaoensi. While the results of nucleotide sequences (Cty b) showed the highest similarity (100%) between M. muntjak and M. truongsonensis and the lowest s (91.5%) among M. putaoensis and M. crinifrons. The phylogenetic tree of muntjac species (16s rRNA gene) shows the main two clusters, the one including M. putaoensis, M. truongsonensis, M. rooseveltorum, and M. muntjak, and the second one including M. crinifrons and M. vuquangensis. The M. reevesi exists separately in the phylogenetic tree. The phylogenetic tree of muntjac species using cytochrome b genes shows that the M. muntjak and M. truongsonensis are clustered in the same group.


2022 ◽  
Vol 18 (1) ◽  
Author(s):  
Hasan Ongor ◽  
Necati Timurkaan ◽  
Hasan Abayli ◽  
Burak Karabulut ◽  
Hakan Kalender ◽  
...  

Abstract Background Marek’s disease (MD) is a lymphoproliferative disease caused by Gallid alphaherpesvirus 2 (GaHV-2, MDV-1), which primarily affects chickens. However, the virus is also able to induce tumors and polyneuritis in turkeys, albeit less frequently than in chickens. Results This is the first study in Turkey reporting the molecular characterization of a MDV-1 strain detected in a flock of backyard turkeys exhibiting visceral lymphoma. Here, MEQ, vIL-8, pp38 and 132-bp tandem repeat regions, which are frequently preferred in the pathotyping of MDV-1, were examined. It was determined that the MEQ gene of MDV-1/TR-21/turkey strain obtained in the present study encoded 339 amino acids (1020 nt) and had four proline-rich repeat regions (PPPP). Based on the nucleotide sequence of the MEQ gene of the MDV-1/TR-21/turkey strain, a phylogenetic tree was created using the MEGA-X software with the Maximum Likelihood Method (in 1000 replicates). Our strain was highly identical (> 99.8) to the Italian/Ck/625/16, Polish (Polen5) and some Turkish (Layer-GaHV-2-02-TR-2017, Tr/MDV-1/19) MDV-1 strains. Also, nt and aa sequences of the MEQ gene of our strain were 99.1 and 99.41% identical to another Turkish strain (MDV/Tur/2019) originated from chickens. Sequence analysis of pp38 and vIL-8 genes also supported the above finding. The identity ratios of nucleotide and amino acid sequences of vIL-8 and pp38 genes of MDV-1/TR-21/turkey strain were 99.64–100% and 99.79–100%, respectively, when compared with those of the Polish strain. According to 132-bp tandem repeat PCR results, the MDV-1/TR-21/turkey strain had five copies. Conclusions These results suggested that the MDV-1/TR-21/turkey strain obtained from backyard turkeys can be either very virulent or very virulent plus pathotype, though experimental inoculation is required for precise pathotyping.


2022 ◽  
Vol 12 (1) ◽  
pp. 168
Author(s):  
Eisa Abdul-Wahhab Al-Tarawnah ◽  
Mariam Al-Qahtani

This study aims to compare the effect of test length on the degree of ability parameter estimation in the two-parameter and three-parameter logistic models, using the Bayesian method of expected prior mode and maximum likelihood. The experimental approach is followed, using the Monte Carlo method of simulation. The study population consists of all subjects with the specified ability level. The study includes random samples of subjects and of items. Results reveal that estimation accuracy of the ability parameter in the two-parameter logistic model according to the maximum likelihood method and the Bayesian method increases with the increase in the number of test items. Results also show that with long and average length tests, the effectiveness is related to the maximum likelihood method and to all conditions of the sample size, whereas in short tests, the Bayesian method of prior mode outperformed in all conditions. Results indicate that the increase of the ability parameter in the three-parameter logistic model increases with the increase of test items number. The Bayesian method outperforms with respect to the accuracy of estimation at all conditions of the sample size, whereas in long tests the maximum likelihood method outperforms at all different conditions.   Received: 17 September 2021 / Accepted: 24 November 2021 / Published: 3 January 2022


2022 ◽  
Vol 4 (1) ◽  
pp. 1-14
Author(s):  
BA Demba Bocar ◽  
T. Moussa

In this paper, we study the problem of estimating the unknow parameters in a long memory process based on the maximum likelihood method. We consider again a diffusion model involving fractional Brownian motion. Our goal is to study the consistency of the drift parameter estimates depending on the form of the model.


Author(s):  
Dharam B. Khandhar ◽  
Pritesh P. Bhatt ◽  
Vrinda S. Thaker

<p class="abstract"><strong>Background:</strong> Aristolochiaceae is a unique plant family that contains aristolochic acids (AAs), with around 600 species.</p><p class="abstract"><strong>Methods:</strong> The entire chloroplast genome of <em>Aristolochia bracteolata</em> was sequenced in this work, and fourteen chloroplast (cp) genomes were retrieved from the NCBI database.  </p><p class="abstract"><strong>Results:</strong> We also analyzed six types of microsatellite markers among these species and found some different markers for each species. A molecular phylogeny based on 7 barcode regions i.e. <em>matK,</em> <em>atpF</em> to <em>atpH</em>, <em>psbK</em> to <em>psbI</em>, <em>rbcL, rpoB, rpoC2</em> and <em>rpoC1</em> is proposed for <em>Aristolochia </em>and 16 species from Piperales, <em>Arabidopsis thaliana</em> is taken as an outgroup. Phylogenetic relationships using concatenated protein-coding genes from Chloroplast genomes of Piperales using the maximum likelihood method is also discussed.</p><p class="abstract"><strong>Conclusions:</strong> In the present study we are providing some unique markers<strong> </strong>and phylogenetic relationships among Piperales members which will help in identification, authentication, to prevent adulteration and further investigation of these medicinal plants.</p>


MAUSAM ◽  
2021 ◽  
Vol 63 (4) ◽  
pp. 573-580
Author(s):  
D.T. MESHRAM ◽  
S.D. GORANTIWAR ◽  
A.S. LOHAKARE

This paper deals with the stochastic modeling of weekly evaporation by using Seasonal ARIMA model for weekly evaporation data for the period of 1987-2008 with a total of 1144 readings for semi-arid Solapur station in Maharashtra. ARIMA models of 1st order were selected based on observing autocorrelation function (ACF) and partial autocorrelation function (PACF) of the weekly evaporation series. The model parameters were obtained by using maximum likelihood method with the help of three tests (i.e., standard error, ACF and PACF of residuals and Akaike Information Criteria). Adequacy of the selected models was determined. The ARIMA model that passed the adequacy test was selected for forecasting. The Seasonal ARIMA (1, 0, 1) (1, 0, 1)52 with lower RMSE is finally selected for forecasting of weekly evaporation values, at Solapur.


Author(s):  
Wojciech Niedbała ◽  
Jerzy Błoszyk ◽  
Katarzyna Buczkowska

The cladistic classification of Phthiracaroidea (Niedbała 1986) and Euphthiracaroidea (Mahunka 1990) (Acari, Oribatida), based on morphological symplesio- and synapomorphic characters has been subjected to verification by molecular analysis of mitochondrial COI and nuclear ITS2, 18S and 28S DNA regions. Twenty-one selected species from representative genera of both superfamilies were analyzed. The phylogenetic trees generated by maximum likelihood method confirm the classification of ptyctimous mites resulting from the analysis of morphological characters. Mesoplophoridae, representing the supercohorts Enarthronota, were placed separately to the clade Mixonomata containing Phthiracaroidea and Euphthiracaroidea that are in a sister relationship. The percentage of genetic divergence between the main clades is high in three markers (COI, ITS2 and 28S), it ranges from 36.8% to 38.7% in the barcode marker COI from 26.0% to 35.4% in ITS2 and from 16.2% to 30.0% in 28S, while in 18S it is very low (1.1% - 3.3%). In the Phthiracaroidea, two sister clades Steganacaridae and Phthiracaridae are distinguished. Steganacaridae include three clades Atropacarus, Hoplophthiracarus and Steganacarus with Steganacarus and Tropacarus as the sister clades. Closely related S. (T.) carinatus and S. (T.) pulcherrimus are separate species. Within the Euphthiracaroidea, the four clades: Mesotritia, Microtritia, Acrotritia and Euphthiracarus are resolved. Mesotritia is the most distant, and Microtritia and Acrotritia show the closest relationship.


Author(s):  
Hyojung Lee ◽  
Changyong Han ◽  
Jooyi Jung ◽  
Sunmi Lee

The COVID-19 pandemic has been spreading worldwide with more than 246 million confirmed cases and 5 million deaths across more than 200 countries as of October 2021. There have been multiple disease clusters, and transmission in South Korea continues. We aim to analyze COVID-19 clusters in Seoul from 4 March to 4 December 2020. A branching process model is employed to investigate the strength and heterogeneity of cluster-induced transmissions. We estimate the cluster-specific effective reproduction number Reff and the dispersion parameter κ using a maximum likelihood method. We also compute Rm as the mean secondary daily cases during the infection period with a cluster size m. As a result, a total of 61 clusters with 3088 cases are elucidated. The clusters are categorized into six groups, including religious groups, convalescent homes, and hospitals. The values of Reff and κ of all clusters are estimated to be 2.26 (95% CI: 2.02–2.53) and 0.20 (95% CI: 0.14–0.28), respectively. This indicates strong evidence for the occurrence of superspreading events in Seoul. The religious groups cluster has the largest value of Reff among all clusters, followed by workplaces, schools, and convalescent home clusters. Our results allow us to infer the presence or absence of superspreading events and to understand the cluster-specific characteristics of COVID-19 outbreaks. Therefore, more effective suppression strategies can be implemented to halt the ongoing or future cluster transmissions caused by small and sporadic clusters as well as large superspreading events.


2021 ◽  
Vol 944 (1) ◽  
pp. 012028
Author(s):  
N O Yonatika ◽  
N Widiasih ◽  
M Hamidah ◽  
M D Nurhakim ◽  
H Budiarto ◽  
...  

Abstract Phyllidiella pustulosa are brightly coloured gastropod molluscs frequently found in coral reefs of the tropical Indo-Pacific. Phyllidiella pustulosa is widely distributed in Indonesia, such as Seribu Island, North Sulawesi, West Papua, and Halmahera. Based on the genetic characteristics of an individual’s DNA sequence, differences between species can be identified. In this paper, we would like to provide the molecular analysis and phylogenetic relationship among nudibranchs from Indonesian waters. Identification was made by measuring the genetic distance between species. The phylogenetic tree reconstruction was made using the Kimura 2-parameter model with 1000 times bootstrap with neighbor-joining and maximum likelihood method. There is 46 DNA Sequence obtained from 4 different regions (Seribu Island, Halmahera, North Sulawesi, and West Papua). The genetic distance of West Papua and Halmahera has the smallest value among other populations, which is between 0.0051-1.4629, compared to the population in Halmahera. The phylogenetic tree also shows populations from West Papua and Halmahera are on the same lineage, indicating that the population in West Papua and Halmahera had the closest relation. The study suggested that North Sulawesi, Halmahera and West Papua have genetic mixing of the same region, which is distinctive from Seribu Island.


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