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Sedimentary and geochemical evidence of Eocene climate change in the Xining Basin, northeastern Tibetan Plateau

Science China Earth Sciences 2018年第9期61卷 1292-1305页

作者： abu sadat md.sayem Zhengtang GUO Haibin WU Chunxia ZHANG Fan YANG Guoqiao XIAO Zhilin HE Key Laboratory of Cenozoic Geology and Environment Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China University of Chinese Academy of Sciences Beijing 100049 China Department of Geological Sciences Jahangirnagar University Dhaka 1342 Bangladesh CAS Center for Excellence in Life and Paleoenvironment Bering 100044 China State Key Laboratory of Biogeology and Environmental Geology School of Earth Sciences China University of Geosciences Wuhan 430074 China

The northeastern Tibetan Plateau began to grow during the Eocene and it is important to understand the climatic history of Asia during this period of so-called ‘doubthouse' conditions. However, despite major advances in the last few decades,the evolutionary history and possible mechanisms of Eocene climate change in the northeastern Tibetan Plateau remain *** Xining Basin in the northeastern Tibetan Plateau contains a continuous sequence of Early to Late Eocene non-marine sediments which provides the opportunity to resolve long-term climate changes during this period. In this study, we report the results of analyses of lithofacies, sediment color and geochemistry of bulk samples collected from the Xijigou section of the Xining Basin. An abrupt lithofacies change between the Early(~52–40 Ma) and Late Eocene(~40–34 Ma) indicates a change in the depositional environment from a shallow lake to a playa lake in response to a significant climatic shift. During ~52–40 Ma,higher values of sediment redness(a*), redness/lightness(a*/L*) and higher modified Chemical Index of Weathering(CIW′)indicate a relatively warm and humid climate, while from ~40–34 Ma the lower values of a*, a*/L*and lower CIW′ imply subhumid to semi-arid climatic conditions. The paleoclimatic records indicate a long-term(~52–34 Ma) trend of decreasing chemical weathering, consistent with global climate change. An abrupt sharp excursion of the proxy records during ~42–40 Ma suggests a relatively brief warm interval, corresponding to the Middle Eocene Climatic Optimum(MECO). We suggest that global cooling substantially reduced humidity in inner Asia, resulting in sub-humid to semi-arid climatic conditions after 40 Ma in the Xining Basin, which may have been responsible for the long-term trend of decreasing chemical weathering during the Eocene.

关键词： Eocene Climate change Sediment color Chemical index of weathering Xining Basin Tibetan Plateau

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Climate Variability & Establishment of Rainfall Threshold Line for Landslide Hazards in Rangamati, Bangladesh

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Open Journal of Geology 2023年第9期13卷 959-979页

作者： Mahmuda Khatun abu Taher Mohammad Shakhawat Hossain Hossain md. sayem Department of Geological Sciences Jahangirnagar University Savar Dhaka Bangladesh

This study aims to evaluate the impact of extreme rainfall events on landslides under current and past climate scenarios. Rainfall-triggered landslides are analyzed by rainfall estimates, derived using statistics of events. It is established that recent climate changes, mainly temperature and rainfall patterns have significantly increased the rainfall-induced landslide hazards in the Rangamati district, Bangladesh. It is also observed that the temperature and rainfall of Rangamati had increased gradually during the last 40 years (1981-2021). On 13 June 2017, a series of landslides triggered by heavy monsoon rains (300 mm/24 h) occurred and killed more than 112 people in the Rangamati hill district, Bangladesh. The highest annual decade rainfall is 3816 mm, recorded in 2010-21. A relationship between causalities and the number of events has also been established. The analysis shows that both antecedent and single-day major rainfall patterns can influence sliding events. It is established that monsoonal rainfall (June-September) can significantly influence catastrophic landslide hazard events. Finally, two rainfall threshold lines for the researched area are constructed based on antecedent and single-day major rainfall occurrences, as well as the number of fatalities caused by landslides. Total rainfall of 100 mm (16.66 mm/day) during six days appears to define the minimum rainfall that has led to shallow landslides/slope failures, while 210 mm (35 mm/day) within six days appears to define the lowest rainfall that could be a cause of catastrophic landslide in Rangamati district.

关键词： Climate Change Antecedent Rainfall Rainfall Threshold Catastrophic and Landslide

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Multistage Triaxial Behavior of Shallow Landslide Hazard Site Soil of Rangamati Sadar Area, Bangladesh

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Engineering（科研） 2023年第10期15卷 581-595页

作者： Mahmuda Khatun abu Taher Mohammad Shakhawat Hossain Hossain md. sayem Department of Geological Sciences Jahangirnagar University Dhaka Bangladesh

The soil samples were collected from a shallow landslide hazard site of the Rangamati Sadar in Bangladesh to determine the shear strength properties of the soil. Multistage triaxial consolidation undrained test has become worldwide more accepted to determine the shear strength parameters. Multistage triaxial undrained tests were performed on five samples taken from five different depths of boreholes. Samples were evaluated under two natural conditions and three remolded situations. Samples were consolidated before shearing at confining pressures from 50 kPa to 1200 kPa. All the test results are discussed in terms of deviator stress versus axial strain, mean effective stress versus deviator curves, stress ratio versus axial strain, and excess p. w. p. versus axial strain curves. The samples consolidated at low effective stress first displayed peak positive values of excess p. w. p., followed by increased strains due to sample bulging failure, and only a few samples formed a shear surface failure. The strength parameters were estimated using the maximum deviator stress as the failure criterion i.e. the overall value of the cohesion is 20 kPa and the friction angle is 34°. Hence, the critical state line has been constructed and the critical state parameters have been calculated. The critical state stress ratio M was calculated to be 0.036. The shear strength of soil is one of the significant mechanical properties that are thoroughly used to assess the landslide and liquefaction potentiality of the soil.

关键词： Multistage Triaxial Shear Strength Critical State Stress Path Landslide

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Effect of Nutritional Support on Treatment of Multi-Drug Resistant Tuberculosis in Rajshahi Division, Bangladesh

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Journal of Tuberculosis Research 2020年第4期8卷 223-236页

作者： md. abu sayem md. Golam Hossain Tahmeed Ahmed Khaled Hossain Zahangir Alam Saud Institute of Biological Sciences University of Rajshahi Rajshahi Bangladesh Department of Statistics University of Rajshahi Rajshahi Bangladesh Department of Public Health James P. Grant School of Public Health Dhaka Bangladesh Department of Biochemistry and Molecular Biology University of Rajshahi Rajshahi Bangladesh

Introduction: Multi-drug resistant tuberculosis (mdR-TB) is a public health crisis throughout the world including Bangladesh particularly due to its complexities in diagnosis, longer treatment regimen, and adverse dru... 详细信息

Introduction: Multi-drug resistant tuberculosis (MDR-TB) is a public health crisis throughout the world including Bangladesh particularly due to its complexities in diagnosis, longer treatment regimen, and adverse drug reaction. Nutritional supplementation has significant impact on patient’s weigh gain and optimum weight gain is a biomarker of treatment response. The objective of this study was to measure body mass index (BMI) progress among MDR-TB patients in different phases of treatment. Methodology: A prospective observational study was conducted from March 2010 to July 2015 in Chest Disease Hospital (CDH), Rajshahi and different communities of Rajshahi Division, Bangladesh. A total of 233 confirmed MDR-TB patients were selected from CDH who received treatment and nutritional support from ongoing national TB control program (NTP). They received free diagnosis, follow up tests, treatment and nutritional support as regular diet as well as cash amount Bangladeshi taka (BDT.) 1000 per month in CDH. Along with treatment, they also received only cash amount BDT. 1500 per month as nutritional support at community level. Weight measurement was taken at regular interval from enrollment to completion of treatment. Chi-square, paired t-test and linear regression analysis were used in this study.

关键词： Bangladesh BMI Progress mdR-TB Nutritional Support

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Crystallization, Transport and Magnetic Properties of the Amorphous (Fe1–xMnx)75P15C10Alloys

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Journal of Crystallization Process and Technology 2012年第3期2卷 105-110页

作者： md. Kamruzzaman md. abu sayem Karal Dilip Kumar Saha Feroz Alam Khan Bangladesh University of Engineering and Technology (BUET) Dhaka-1000 Bangladesh Department of Physics Begum Rokeya University Rangpur Rangpur-5400 Bangladesh Materials Science Division Atomic Energy Center Dhaka-1000 Bangladesh

The amorphous (Fe1-xMnx)75P15C10 (0 ≤ x ≥ 0.30) alloys were prepared by the standard melt spinning technique and investigated their crystallization, thermal, transport and magnetic properties. Crystallization was observed from 400℃ to 650℃ with an interval 50℃within 30 minutes annealing time by XRD. The as-cast samples were amorphous in nature. Annealing 400℃ to 450℃ samples showed the mixed bcc Fe and amorphous structures. The lattice parameter ‘a’ was varied from 2.855 to 2.859 ? but above 450℃, samples contained hexagonal, FeP and FeC structures. The lattice parameters ‘a’ and ‘c’ were varied from (5.016-5.036) ? and (13.575-13.820) ? , respectively. Average crystallite size was found to vary from 8 to 48 nm. Crystallization temperature and weight change were observed by differential thermal analysis and thermogravimetric analysis, respectively. Crystallization temperature was increased with increasing Mn content. Resistivity was increased above and bellows the Curie temperature. Real permeability remained almost constant upto around 106 Hz for of all samples after that it was decreased with increasing frequency and it was also decreased with Mn, whereas imaginary permeability was increased sharply above frequency 107 Hz. The value of saturation magnetization was found to decrease with increment Mn.

关键词： Metallic Glass Melt Spinning Technique Crystallization DTA VSM

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EFFECT OF TEMPERATURE,p H AND METAL IONS ON THE ACTIVITY AND STABILITY OF ALKALINE PROTEASE FROM NOVEL BACILLUS LICHENIFORMIS MZK03

EFFECT OF TEMPERATURE,p H AND METAL IONS ON THE ACTIVITY AND...

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The 4th Session of 2006 Workshop of Pakistan Academy of Sciences

作者： S.M.abu sayem M.J.Alam md.Mozammel Hoq Department of Microbiology University of Dhaka Department of Biotechnology Shah Jalal University of Science and Technology

The effect of temperature,p H and metal ions on the activity and stability of crude protease from Bacillus licheniformis MZK03 was *** fermentation in shake culture revealed that maximum level of enzyme was produced at 37°C and p H 8.5 after 39 hr at 120 *** lost its activity rapidly above 50°C and half-life of the protease at this temperature was 50 min with optimum activity at 40°*** was most stable at p H 8.5 and lost its activity rapidly above p H 10.0,and at p H 11.0 reached30% of the activity obtained at p H *** enzyme lost its activity completely at p H *** proteolytic activity was found at 40 o C and p H *** enzyme activity was accelerated by the addition of Mg2+,Ca2+ and Mn2+,whereas it was inhibited by Hg2+.

关键词： Bacillus licheniformis alkaline protease fermentation half life proteoytic activity

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The Hidden Earthquake Induced Liquefaction Risks in the Rohingya Refugee Camp Hills & Surrounding Areas of Ukhiya, Cox’s Bazar, Bangladesh—A Geotechnical Engineering Approach

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Open Journal of Earthquake Research 2023年第3期12卷 114-138页

作者： abu Taher Mohammad Shakhawat Hossain md. Shakil Mahabub Tanmoy Dutta Mahmuda Khatun Toru Terao md. Hasan Imam Hossain md.sayem md. Emdadul Haque Purba Anindita Khan Sheikh Jafia Jafrin Geological Engineering Geohazards & Disaster Sciences Research Group Department of Geological Sciences Jahangirnagar University Dhaka Bangladesh Geological Engineering Geohazards & Disaster Sciences Research Group Department of Geological Sciences Jahangirnagar Univer-sity Dhaka Bangladesh Graduate School of Science for Creative Emergence Kagawa University Kagawa Japan

Liquefaction is one of the major catastrophic geohazards which usually occurs in saturated or partially saturated sandy or silty soils during a seismic event. Evaluating the potential liquefaction risks of a seismically prone area can significantly reduce the loss of lives and damage to civil infrastructures. This research is mainly focused on the earthquake-induced liquefaction risk assessment based on Liquefaction Potential Index (LPI) values at different earthquake magnitudes (M = 5.0, 7.0 and 8.0) with a peak ground acceleration (amax) of 0.28 g in the Rohingya Refugee camp and surrounding areas of Ukhiya, Cox’s Bazar, Bangladesh. Standard Penetration Test (SPT) results have been evaluated for potential liquefaction assessment. The soils are mainly composed of very loose to loose sands with some silts and clays. Geotechnical properties of these very loose sandy soils are very much consistent with the criteria of liquefiable soil. It is established from the grain size analysis results;the soil of the study area is mainly sand dominated (SP) with some silty clay (SC) which consists of 93.68% to 99.48% sand, 0.06% to 4.71% gravel and 0% to 6.26% silt and clay. Some Clayey Sand (SC) is also present. The silty clay can be characterized as medium (CI) to high plasticity (CH) inorganic clay soil. LPI values have been calculated to identify risk zones and to prepare risk maps of the investigated area. Based on these obtained LPI values, four (4) susceptible liquefaction risk zones are identified as low, medium, high and very high. The established “Risk Maps” can be used for future geological engineering works as well as for sustainable planning, design and construction purposes relating to adaptation and mitigation of seismic hazards in the investigated area.

关键词： Earthquake Magnitude Factor of Safety (Fs) Liquefaction Potential Index (LPI) & Risk

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Predictors of Death in Under-Five Children with Sepsis Attending an Urban Diarrheal Treatment Centre in Bangladesh

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Food and Nutrition Sciences 2013年第7期4卷 709-714页

作者： K. M. Shahunja abu sadat Mohammad Sayeem Bin Shahid Hasan Ashraf abu Syeed Golam Faruque Sumon Kumar Das md. Kamruzzaman Farhana Pervin Flora Mohammod Jobayer Chisti Centre for Nutrition and Food Security International Centre for Diarrhoeal Disease Research (icddrb) Dhaka Bangladesh Centre for Nutrition and Food Security International Centre for Diarrhoeal Disease Research (icddrb) Dhaka Bangladesh Clinical Service Dhaka Hospital International Centre for Diarrhoeal Disease Research (icddrb) Dhaka Bangladesh Dhaka Shishu (Children) Hospital Dhaka Bangladesh.

SETTING: Special Care Ward (SCW) of the Dhaka Hospital of icddr,b, Bangladesh. OBJECTIVE: To evaluate the clinical and laboratory predictors of death in under-five children with clinically defined sepsis presenting with diarrhea. METHODS: We prospectively enrolled all the diarrheal children (n = 151) aged 0 to 59 months with clinical sepsis admitted in the SCW during September’2007 through December’2007. Comparison was made between deaths (n = 23) and survivors (n = 128). Sepsis is defined as presence of inflammation [abnormal WBC count (>11 × 109/L or, 9/L or, band and neutrophil ratio ≤0.10] plus presence or presumed presence of infection with thermo-instability [hypo (≤35.0℃) or hyperthermia (≥38.5℃)], tachycardia, tachypnea, and/or the indications of altered organ function (altered mental status and bounding pulse) in the absence of clinical dehydration or after correction of dehydration. RESULTS: The median (inter-quartile range) age (months) of the children who survived and died was comparable [4.0 (2.0, 12.0) vs. 1.5 (0.8, 10.0);p = 0.703]. In the logistic regression analysis, after adjusting for potential confounders, such as abnormal WBC count, use of intravenous fluid, patient with fatal outcome more often presented with hypernatremia (odds ratio = 16.48, 95% confidence interval = 2.21 -?123.12;p = 0.006), lobar consolidation (odds ratio = 19.9, 95% confidence interval = 2.99 - 132.80;p = 0.002), hypoxemia (odds ratio = 14.78, 95% confidence interval = 1.38 157.90;p = 0.026) and severe under-nutrition (odds ratio = 7.57, 95% confidence interval = 1.24 - 46.11;p = 0.028). CONCLUSIONS: Our data suggest that children under-five with clinical sepsis who present with lobar pneumonia, hypoxaemia, severe acute malnutrition and hyperntaemia are at higher risk of death and identification of these simple factors may help clinicians to take prompt initiative for the aggressive management of such children especially in a resource-limited setting like Bangladesh.

关键词： Bangladesh Diarrhea Hypoxemia Sepsis Severe Malnutrition

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Climate Variability & Establishment of Rainfall Threshold Line for Landslide Hazards in Rangamati, Bangladesh

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Open Journal of Geology（地质学期刊） 2023年第9期

作者： Mahmuda Khatun abu Taher Mohammad Shakhawat Hossain Hossain md.sayem

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