Pub Date : 2023-10-18DOI: 10.3329/dujs.v71i2.69126
Tareq Rahman, Md Israt Rayhan
The financial value of money and the overall stability of an economy are significantly impacted by inflation. To investigate the effect of the COVID-19 pandemic and the Russia-Ukraine war on constant inflation rates in South and Southeast Asian countries between January 2019 and December 2022, this research utilizes monthly inflation rate data from the International Monetary Fund. Autoregressive integrated moving average modeling and prediction of inflation rates and the Bai-Perron method to estimate the structural breakdown of monthly inflation rate series are employed. Graphical methods and theoretical tests are used to diagnose the models, and the Chow test is utilized to assess structural breakdown in the monthly inflation rate series. The findings indicate that the Russia-Ukraine war since February 2022 has a more significant impact on the selected countries than the COVID-19 pandemic during January 2020 to December 2021.
Dhaka Univ. J. Sci. 71(2): 169-175, 2023 (July)
{"title":"Impact of COVID-19 and Russia-Ukraine war on the inflation rate of South and Southeast Asia","authors":"Tareq Rahman, Md Israt Rayhan","doi":"10.3329/dujs.v71i2.69126","DOIUrl":"https://doi.org/10.3329/dujs.v71i2.69126","url":null,"abstract":"The financial value of money and the overall stability of an economy are significantly impacted by inflation. To investigate the effect of the COVID-19 pandemic and the Russia-Ukraine war on constant inflation rates in South and Southeast Asian countries between January 2019 and December 2022, this research utilizes monthly inflation rate data from the International Monetary Fund. Autoregressive integrated moving average modeling and prediction of inflation rates and the Bai-Perron method to estimate the structural breakdown of monthly inflation rate series are employed. Graphical methods and theoretical tests are used to diagnose the models, and the Chow test is utilized to assess structural breakdown in the monthly inflation rate series. The findings indicate that the Russia-Ukraine war since February 2022 has a more significant impact on the selected countries than the COVID-19 pandemic during January 2020 to December 2021.
 Dhaka Univ. J. Sci. 71(2): 169-175, 2023 (July)","PeriodicalId":22453,"journal":{"name":"The Dhaka University Journal of Science","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135883326","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-18DOI: 10.3329/dujs.v71i2.69092
PD Gupta, Ishtiaque M Syed
In this research work the non-linear refractive indices n2 was determined for the pure SnO2 and TiO2 doped SnO2 thin films by using the Z-scan technique. We have used a continuous wave Ar-ion laser with incident wavelength of 514 nm as the source. n2 was measured by varying three quantities: the incident laser intensity, thickness of the pure SnO2 films and doping concentration of TiO2 in SnO2 films. From the experimental results, the values of n2 were found to be increasing with the increase of thickness of the pure SnO2 films and also with the increase of doping concentration of TiO2 in SnO2 thin films. Dhaka Univ. J. Sci. 71(2): 104-110, 2023 (July)
{"title":"Determination of Non-linear Refractive Index of Pure SnO2 and TiO2 Doped SnO2 Thin Films Using Z-scan Technique","authors":"PD Gupta, Ishtiaque M Syed","doi":"10.3329/dujs.v71i2.69092","DOIUrl":"https://doi.org/10.3329/dujs.v71i2.69092","url":null,"abstract":"In this research work the non-linear refractive indices n2 was determined for the pure SnO2 and TiO2 doped SnO2 thin films by using the Z-scan technique. We have used a continuous wave Ar-ion laser with incident wavelength of 514 nm as the source. n2 was measured by varying three quantities: the incident laser intensity, thickness of the pure SnO2 films and doping concentration of TiO2 in SnO2 films. From the experimental results, the values of n2 were found to be increasing with the increase of thickness of the pure SnO2 films and also with the increase of doping concentration of TiO2 in SnO2 thin films. Dhaka Univ. J. Sci. 71(2): 104-110, 2023 (July)","PeriodicalId":22453,"journal":{"name":"The Dhaka University Journal of Science","volume":"252 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135883327","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Carbon-doped ZnO (C-ZnO) was prepared and characterized by XRD, SEM, EDX and FT-IR spectroscopy. The substitution of oxygen in the lattice of ZnO by carbon greatly extends its optical sensitivity in the visible light due to the band gap’s shrinkage, which promotes the effectiveness of electron-hole separation. SEM images showed that the surface of C-ZnO catalyst is different from that of undoped ZnO. Analysis of the elements present in the sample was done by EDX which affirms that the prepared sample contains Zn, O and C atoms. The existence of ZnO as wurtzite is confirmed by XRD analysis exhibiting little deviation of the peak position due to the presence of carbon in substitutional sites. FT-IR analysis also supports these results. Under visible light irradiation, the prepared C-ZnO shows better photocatalytic efficiency on methylene blue (MB) than un-doped ZnO. The optimum photodegradation efficiency of MB has been observed when 2 percent C-doped ZnO obtained at 300˚C calcination temperature.
Dhaka Univ. J. Sci. 71(2): 127-133, 2023 (July)
{"title":"Preparation and Characterization of Carbon Doped ZnO and Its Effectiveness as Photocatalyst under Visible Light","authors":"Mahbuba Zaman, Nasrin Akter, Md Ataur Rahman, Md Mufazzal Hossain","doi":"10.3329/dujs.v71i2.69121","DOIUrl":"https://doi.org/10.3329/dujs.v71i2.69121","url":null,"abstract":"Carbon-doped ZnO (C-ZnO) was prepared and characterized by XRD, SEM, EDX and FT-IR spectroscopy. The substitution of oxygen in the lattice of ZnO by carbon greatly extends its optical sensitivity in the visible light due to the band gap’s shrinkage, which promotes the effectiveness of electron-hole separation. SEM images showed that the surface of C-ZnO catalyst is different from that of undoped ZnO. Analysis of the elements present in the sample was done by EDX which affirms that the prepared sample contains Zn, O and C atoms. The existence of ZnO as wurtzite is confirmed by XRD analysis exhibiting little deviation of the peak position due to the presence of carbon in substitutional sites. FT-IR analysis also supports these results. Under visible light irradiation, the prepared C-ZnO shows better photocatalytic efficiency on methylene blue (MB) than un-doped ZnO. The optimum photodegradation efficiency of MB has been observed when 2 percent C-doped ZnO obtained at 300˚C calcination temperature.
 Dhaka Univ. J. Sci. 71(2): 127-133, 2023 (July)","PeriodicalId":22453,"journal":{"name":"The Dhaka University Journal of Science","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135884238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-18DOI: 10.3329/dujs.v71i2.69090
Bikash Pal, Abu Zar Md Shafiullah
The Government of Bangladesh is very much aware of controlling excessive birth rate to maintain population problem. Though Bangladesh is owning self-sufficiency in many sectors, the increasing population is a great impediment for the development of the country. So, promoting different contraceptive methods is of much importance. This work aims at identifying the important determinants that affect the long-acting and permanent methods (LAPM) of contraception. Firstly, chi-square test of association is carried out for defining the correlates of LAPM of contraception using Bangladesh Demographic and Health Survey (BDHS), 2017-18 data. For estimating the effects of each controlled independent variables, data are further analyzed within a multivariate framework. To obtain consistent and efficient estimates of parameters of interest, multinomial logistic regression model is used in this work. The study finds several socio-economic and demographic variables having high impact on using LAPM. The study findings are properly discussed and recommendations are made accordingly for the policy makers.
Dhaka Univ. J. Sci. 71(2): 87-94, 2023 (July)
{"title":"Factors of Using Long Acting and Permanent Methods (LAPM) of Contraception: Bangladesh Perspective","authors":"Bikash Pal, Abu Zar Md Shafiullah","doi":"10.3329/dujs.v71i2.69090","DOIUrl":"https://doi.org/10.3329/dujs.v71i2.69090","url":null,"abstract":"The Government of Bangladesh is very much aware of controlling excessive birth rate to maintain population problem. Though Bangladesh is owning self-sufficiency in many sectors, the increasing population is a great impediment for the development of the country. So, promoting different contraceptive methods is of much importance. This work aims at identifying the important determinants that affect the long-acting and permanent methods (LAPM) of contraception. Firstly, chi-square test of association is carried out for defining the correlates of LAPM of contraception using Bangladesh Demographic and Health Survey (BDHS), 2017-18 data. For estimating the effects of each controlled independent variables, data are further analyzed within a multivariate framework. To obtain consistent and efficient estimates of parameters of interest, multinomial logistic regression model is used in this work. The study finds several socio-economic and demographic variables having high impact on using LAPM. The study findings are properly discussed and recommendations are made accordingly for the policy makers.
 Dhaka Univ. J. Sci. 71(2): 87-94, 2023 (July)","PeriodicalId":22453,"journal":{"name":"The Dhaka University Journal of Science","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135885157","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A number of complex compounds of aceclofenac with different first-row transition metal ions like Co(II), Mn(II), Ni(II), Cu(II), and Zn (II) were synthesized in an aqueous medium and characterized on the basis of their UV-Visible, FTIR spectra, elemental (C, H, N) analyses, and metal estimation data. Thermogravimetric analysis (TGA) was also done. Conductivity measurement and magnetic susceptibility measurement were also done to have information about the electrolytic behavior of the compounds and oxidation states of the central metal atoms respectively.
Dhaka Univ. J. Sci. 71(2): 153-159, 2023 (July)
{"title":"Preparation and Characterization of Aceclofenac Complexes of First Row Transition Metals Mn(II), Co((II), Ni(II), Cu(II), and Zn(II)","authors":"Md Tanjir Rahman, Saiful Islam, Md Ershad Halim, Shamim Ahmed, M Q Ehsan","doi":"10.3329/dujs.v71i2.69124","DOIUrl":"https://doi.org/10.3329/dujs.v71i2.69124","url":null,"abstract":"A number of complex compounds of aceclofenac with different first-row transition metal ions like Co(II), Mn(II), Ni(II), Cu(II), and Zn (II) were synthesized in an aqueous medium and characterized on the basis of their UV-Visible, FTIR spectra, elemental (C, H, N) analyses, and metal estimation data. Thermogravimetric analysis (TGA) was also done. Conductivity measurement and magnetic susceptibility measurement were also done to have information about the electrolytic behavior of the compounds and oxidation states of the central metal atoms respectively.
 Dhaka Univ. J. Sci. 71(2): 153-159, 2023 (July)","PeriodicalId":22453,"journal":{"name":"The Dhaka University Journal of Science","volume":"183 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135885177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-18DOI: 10.3329/dujs.v71i2.69123
Most Fatema Amin Akhi, Md Saddam Hossain, Md Shakil Hossain, Muhammad Abul Kalam Mallik
The simulations of Severe Cyclonic Storm (SCS) Mora (28-31 May 2017) generated over the Bay of Bengal (BoB) are performed in this study to analyze its features, landfall, and track using the Weather Research and Forecasting (WRF) model. WRF-ARW model has been used on a 10 km Horizontal Resolution (HR) domain for 96, 72, 48, and 24-hour lead time simulations. The model's performance is assessed by examining Mean Sea Level Pressure (MSLP), vertical distribution of velocity components, wind flow pattern, relative vorticity, vertical wind shear, relative humidity, latent heat flux at the surface, and track pattern. The simulated results are compared carefully to the observations from the Bangladesh Meteorological Department (BMD) and the India Meteorological Department (IMD). The findings are reasonably consistent with the observations. The simulated track is also reasonable even up to 72 hours in advance. Finally, the study's results suggest that the WRF model can be used as an effective tool in predicting TCs over the BoB.
Dhaka Univ. J. Sci. 71(2): 142-152, 2023 (July)
{"title":"Simulation of Track and Landfall Process of Severe Cyclonic Storm Mora over the Bay of Bengal using WRF-ARW Model","authors":"Most Fatema Amin Akhi, Md Saddam Hossain, Md Shakil Hossain, Muhammad Abul Kalam Mallik","doi":"10.3329/dujs.v71i2.69123","DOIUrl":"https://doi.org/10.3329/dujs.v71i2.69123","url":null,"abstract":"The simulations of Severe Cyclonic Storm (SCS) Mora (28-31 May 2017) generated over the Bay of Bengal (BoB) are performed in this study to analyze its features, landfall, and track using the Weather Research and Forecasting (WRF) model. WRF-ARW model has been used on a 10 km Horizontal Resolution (HR) domain for 96, 72, 48, and 24-hour lead time simulations. The model's performance is assessed by examining Mean Sea Level Pressure (MSLP), vertical distribution of velocity components, wind flow pattern, relative vorticity, vertical wind shear, relative humidity, latent heat flux at the surface, and track pattern. The simulated results are compared carefully to the observations from the Bangladesh Meteorological Department (BMD) and the India Meteorological Department (IMD). The findings are reasonably consistent with the observations. The simulated track is also reasonable even up to 72 hours in advance. Finally, the study's results suggest that the WRF model can be used as an effective tool in predicting TCs over the BoB.
 Dhaka Univ. J. Sci. 71(2): 142-152, 2023 (July)","PeriodicalId":22453,"journal":{"name":"The Dhaka University Journal of Science","volume":"75 4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135883338","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-18DOI: 10.3329/dujs.v71i2.69091
S M Nasif Shams, A M Mahmudul Hasan, Shams Bin Bony Amin, Gour Chand Mazumder
Biomass can be converted into either heat energy or electrical or energy carriers using both thermo-chemical and bio-chemical conversion. Briquetting is a process where untreated biomass is converted into homogeneous, uniformly sized high density solid blocks. Briquettes are used in boilers, heating plants, thermal power stations and by individual households for heating. Present study focuses on using poultry manure with rice husk and saw dust. Poultry manure mixed with rice husk or saw dust by 60:40 ratio provides comparatively higher bond strength. Calorific value varies significantly with the use of poultry manure and tree leaves as well as its production cost. Pure rice husk contains higher calorific value (HCV) 12.6 MJ/Kg where adding poultry manure reduces its value to 10.3 MJ/Kg and Saw dust shows 10.4 MJ/Kg where pure saw dust has 16.3 MJ/Kg in 60:40 ratios with poultry manure. Addition of 20% tree leaves on weight basis ratio of 40:40:20 with base materials and poultry manure shows 10.5 MJ/Kg and 11.7 MJ/Kg respectively for rice husk and saw dust. Competitive price of briquette for 60:40 ratios with Poultry Manure shows 6 BDT/Kg and 5BDT/Kg when secondary material is added. Moreover, if the machine capacity increases the price is reduced.
Dhaka Univ. J. Sci. 71(2): 95-103, 2023 (July)
{"title":"Development of Cost-Effective Fuel Briquette with Poultry Manure","authors":"S M Nasif Shams, A M Mahmudul Hasan, Shams Bin Bony Amin, Gour Chand Mazumder","doi":"10.3329/dujs.v71i2.69091","DOIUrl":"https://doi.org/10.3329/dujs.v71i2.69091","url":null,"abstract":"Biomass can be converted into either heat energy or electrical or energy carriers using both thermo-chemical and bio-chemical conversion. Briquetting is a process where untreated biomass is converted into homogeneous, uniformly sized high density solid blocks. Briquettes are used in boilers, heating plants, thermal power stations and by individual households for heating. Present study focuses on using poultry manure with rice husk and saw dust. Poultry manure mixed with rice husk or saw dust by 60:40 ratio provides comparatively higher bond strength. Calorific value varies significantly with the use of poultry manure and tree leaves as well as its production cost. Pure rice husk contains higher calorific value (HCV) 12.6 MJ/Kg where adding poultry manure reduces its value to 10.3 MJ/Kg and Saw dust shows 10.4 MJ/Kg where pure saw dust has 16.3 MJ/Kg in 60:40 ratios with poultry manure. Addition of 20% tree leaves on weight basis ratio of 40:40:20 with base materials and poultry manure shows 10.5 MJ/Kg and 11.7 MJ/Kg respectively for rice husk and saw dust. Competitive price of briquette for 60:40 ratios with Poultry Manure shows 6 BDT/Kg and 5BDT/Kg when secondary material is added. Moreover, if the machine capacity increases the price is reduced.
 Dhaka Univ. J. Sci. 71(2): 95-103, 2023 (July)","PeriodicalId":22453,"journal":{"name":"The Dhaka University Journal of Science","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135884858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Spectrophotometric reagents 3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine (PDT) and 3-(2-pyridyl)-5,6-bis(p-methoxyphenyl)- 1,2,4-triazine (PBMPT) were prepared from commercially available reactants simply by condensing pyridyl-2-hydrazidine with 1,2-dicarbonyl compounds. These organic reagents were used further to determine the trace amount of iron in various natural and food samples by spectrophotometric method. The absorptiometric features of iron (II) complexes of PDT and PBMPT were determined. The molar absorptivites of iron (II) complexes of PDT and PBMPT were found to be 24,181 L mol-1 cm-1 (at 556.0 nm) and 32,091 L mol-1 cm-1 at (561.8 nm) respectively. The reliability of these absorptivities were verified by standard addition technique and also by comparing the results of atomic absorption spectroscopy method. The complexes of both the reagents obey Beer’s law within the experimental concentration range 0.032mg/L - 0.159 mg/L.
Dhaka Univ. J. Sci. 71(2): 111-116, 2023 (July)
以市售反应物为原料，将吡啶-2-肼与1,2-二羰基化合物缩合，制备了分光光度试剂3-(2-吡啶基)-5,6-二苯基-1,2,4-三嗪(PDT)和3-(2-吡啶基)-5,6-双(对甲氧基苯基)- 1,2,4-三嗪(PBMPT)。这些有机试剂进一步应用分光光度法测定了各种天然和食品样品中的痕量铁。测定了PDT和PBMPT的铁(II)配合物的吸收特性。PDT和PBMPT的铁(II)配合物的摩尔吸收率分别为24,181 L mol-1 cm-1 (556.0 nm)和32,091 L mol-1 cm-1 (561.8 nm)。通过标准加入法和原子吸收光谱法的结果对比，验证了这些吸收系数的可靠性。在0.032mg/L ~ 0.159 mg/L的实验浓度范围内，两种试剂配合物均服从比尔定律。
达卡大学学报(自然科学版)，71(2):111- 116,2023 (7)
{"title":"Preparation of Some as-Triazines, Their Evaluation as Spectrophotometric Reagents and Determination of Trace Amount of Iron in Certain Food and Natural Samples","authors":"Maksuda Parvin, Munira Mushtari, Afifa Rahman, Nazmin Akter, Md Anwarul Islam","doi":"10.3329/dujs.v71i2.69093","DOIUrl":"https://doi.org/10.3329/dujs.v71i2.69093","url":null,"abstract":"Spectrophotometric reagents 3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine (PDT) and 3-(2-pyridyl)-5,6-bis(p-methoxyphenyl)- 1,2,4-triazine (PBMPT) were prepared from commercially available reactants simply by condensing pyridyl-2-hydrazidine with 1,2-dicarbonyl compounds. These organic reagents were used further to determine the trace amount of iron in various natural and food samples by spectrophotometric method. The absorptiometric features of iron (II) complexes of PDT and PBMPT were determined. The molar absorptivites of iron (II) complexes of PDT and PBMPT were found to be 24,181 L mol-1 cm-1 (at 556.0 nm) and 32,091 L mol-1 cm-1 at (561.8 nm) respectively. The reliability of these absorptivities were verified by standard addition technique and also by comparing the results of atomic absorption spectroscopy method. The complexes of both the reagents obey Beer’s law within the experimental concentration range 0.032mg/L - 0.159 mg/L.
 Dhaka Univ. J. Sci. 71(2): 111-116, 2023 (July)","PeriodicalId":22453,"journal":{"name":"The Dhaka University Journal of Science","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135883331","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-18DOI: 10.3329/dujs.v71i2.69122
Md Siddiqur Rahman, Sabina Sharmin
For building a linear prediction model, robust Backward Elimination (RBE) algorithm, which is computationally useful and scalable to high-dimensional large datasets, is introduced in this investigation. Backward Elimination (BE) can be stated in terms of sample correlations and simple RBE can be obtained by swapping out these correlations with their corresponding robust counterparts. The robust correlation for winsorized data was employed based on the adjusted winsorized correlation as a robust bivariate correlation. In another study, the Spearman rank correlation was employed as a robust bivariate correlation. However, the RBE has some drawbacks in the presence of multivariate outliers. In this article, the usage of FastMCD (Fast minimum covariance determinant)-based correlation is proposed in BE to reduce the influence of outlying data points. We call this proposed method BEmcd. A comprehensive simulation study was conducted to evaluate the performance of BEmcd with that of RBE based on winsorized correlation and Spearman rank correlation. Simulations and an application of actual data demonstrate the outstanding performance of BEmcd.
Dhaka Univ. J. Sci. 71(2): 134-141, 2023 (July)
{"title":"Robust Multiple Linear Backward EliminationRegression","authors":"Md Siddiqur Rahman, Sabina Sharmin","doi":"10.3329/dujs.v71i2.69122","DOIUrl":"https://doi.org/10.3329/dujs.v71i2.69122","url":null,"abstract":"For building a linear prediction model, robust Backward Elimination (RBE) algorithm, which is computationally useful and scalable to high-dimensional large datasets, is introduced in this investigation. Backward Elimination (BE) can be stated in terms of sample correlations and simple RBE can be obtained by swapping out these correlations with their corresponding robust counterparts. The robust correlation for winsorized data was employed based on the adjusted winsorized correlation as a robust bivariate correlation. In another study, the Spearman rank correlation was employed as a robust bivariate correlation. However, the RBE has some drawbacks in the presence of multivariate outliers. In this article, the usage of FastMCD (Fast minimum covariance determinant)-based correlation is proposed in BE to reduce the influence of outlying data points. We call this proposed method BEmcd. A comprehensive simulation study was conducted to evaluate the performance of BEmcd with that of RBE based on winsorized correlation and Spearman rank correlation. Simulations and an application of actual data demonstrate the outstanding performance of BEmcd.
 Dhaka Univ. J. Sci. 71(2): 134-141, 2023 (July)","PeriodicalId":22453,"journal":{"name":"The Dhaka University Journal of Science","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135884247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-18DOI: 10.3329/dujs.v71i2.69094
M Ershadul Haque, Sabina Sharmin, Sayema Sharmin
In recent years Caesarean Section (C-S)is considered as an important mode of child delivery in lowering mother and infant mortality. However, the unnecessary use of C-S has detrimental impacts on both mothers’ and newborns’ health. The purpose of this study is to evaluate the prevalence of caesarean delivery and to find out the related factors influencing the rapid rise in C-Sin Bangladesh by considering an appropriate statistical model in line with the data structure. The study is based on the data from the 2017-2018 BDHS which is a nationally representative survey. BDHS is conducted periodically and 2017-2018 is the latest of all the BDHS conducted so far. Information used in the present study was collected from 5230 mothers who provided complete information about all the variables considered in the study. Among the Bangladeshi women, the rate of Caesarean sections (C-S) was reported to be 32.94% which is high in any international standard. Multilevel analysis suggests that the highest education level, current working status, wealth index, media exposure, number of decisions in which women participated, age at birth, BMI, birth order of the index child, number of ANC visits during the period of pregnancy, and childbirth weight have significant influence on whether mothers deliver babies through the C-S. In order to prevent needless caesarean deliveries and safeguard mothers from the consequences, Bangladesh urgently needs caesarean delivery policy guidelines. The study will help the policymaker in taking such initiatives.
Dhaka Univ. J. Sci. 71(2): 117-126, 2023 (July)
{"title":"Determinants of Caesarean Section in Bangladesh: A Multilevel Analysis of BDHS 2017-2018 Data","authors":"M Ershadul Haque, Sabina Sharmin, Sayema Sharmin","doi":"10.3329/dujs.v71i2.69094","DOIUrl":"https://doi.org/10.3329/dujs.v71i2.69094","url":null,"abstract":"In recent years Caesarean Section (C-S)is considered as an important mode of child delivery in lowering mother and infant mortality. However, the unnecessary use of C-S has detrimental impacts on both mothers’ and newborns’ health. The purpose of this study is to evaluate the prevalence of caesarean delivery and to find out the related factors influencing the rapid rise in C-Sin Bangladesh by considering an appropriate statistical model in line with the data structure. The study is based on the data from the 2017-2018 BDHS which is a nationally representative survey. BDHS is conducted periodically and 2017-2018 is the latest of all the BDHS conducted so far. Information used in the present study was collected from 5230 mothers who provided complete information about all the variables considered in the study. Among the Bangladeshi women, the rate of Caesarean sections (C-S) was reported to be 32.94% which is high in any international standard. Multilevel analysis suggests that the highest education level, current working status, wealth index, media exposure, number of decisions in which women participated, age at birth, BMI, birth order of the index child, number of ANC visits during the period of pregnancy, and childbirth weight have significant influence on whether mothers deliver babies through the C-S. In order to prevent needless caesarean deliveries and safeguard mothers from the consequences, Bangladesh urgently needs caesarean delivery policy guidelines. The study will help the policymaker in taking such initiatives.
 Dhaka Univ. J. Sci. 71(2): 117-126, 2023 (July)","PeriodicalId":22453,"journal":{"name":"The Dhaka University Journal of Science","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135884239","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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