Differences In Seasonal Variation Research Articles

Retracted: Optimization of Land Use Regression Modelling of PM2.5 Spatial Variations in Different Seasons across China

Retracted: Optimization of Land Use Regression Modelling of PM_2.5 Spatial Variations in Different Seasons across China

Physiological and Ecological Study of some Algae and Aquatic Plants

The aim of the study was to find out the chemical content of some algae, Enteromorpha and Cladophora, and some selected aquatic plants, Typha domingensis, Phragmites australis and Schoenoplectus lacustris. were studied Ashes, fats and mineral elements, which include magnesium, phosphate and nitrogen, in addition to studying the physical and chemical properties of water at different times of the seasons. Enteromorpha moss showed the highest percentage of ash which amounted to (14.32%), magnesium (0.43%) and phosphate (2.73%) while Cladophora moss showed the highest percentage of fat which amounted to (7.28%) and nitrogen (3.92%). The plants showed clear significant differences in different seasons where the results showed that the highest value of ash for Typha domingensis was in spring (11.11%), for Phragmites australis in summer (12.43%) and for Schoenoplectus lacustris in autumn (16.21%). As for fats the highest value of fats was in the spring season for the Typha domingensis plant (3.10%), for the Phragmites australis plant in the autumn season (1.51%), and for the Schoenoplectus lacustris plant in the summer season (2.21%). As for magnesium, the highest value of magnesium was in the winter season for the Typha domingensis plant (0.25%), for the Phragmites australis plant in the summer season (0.76%), and for the Schoenoplectus lacustris plant in the autumn season (2.45%). As for phosphateits highest value was in the autumn season for the Typha domingensis plant (0.26%), for the Phragmites australis plant in the spring season (0.32%), and for the Schoenoplectus lacustris plant in the autumn season (0.24%). Also the physical and chemical properties of water showed great variations in different seasons as the highest recorded value of air and water temperature in summer was (41) and (40) Celsius respectively. As for the pH, the highest value was recorded in the winter season (8.16), and the nitrates recorded the highest value in the autumn season (45.35) mg / L.

Enterovirus Meningitis without Pleocytosis: a Retrospective Observational Study in Adults.

Reverse-transcription polymerase chain reaction (RT-PCR)-confirmed enterovirus (EV) meningitis without pleocytosis has only been previously reported in children. In this study, we examined the frequency of EV meningitis without pleocytosis in adults and compared its clinical features. We retrospectively analyzed the data of adult patients with EV meningitis confirmed using cerebrospinal fluid (CSF) RT-PCR. Among the 17 patients included in this study, 58.8% showed no pleocytosis. The median age and clinical symptoms did not differ between the pleocytosis and non-pleocytosis groups. There were no statistically significant differences in seasonal variation or time from the onset of meningitis symptoms to lumbar puncture. The peripheral white blood cell (WBC) count in patients with pleocytosis was significantly higher than that in patients without pleocytosis. The median CSF pressure showed a higher trend in the non-pleocytosis group. Patients with CSF pressures higher than normal were more common in the non-pleocytosis group. The median CSF protein values were higher than the normal values in both groups. We confirmed the high frequency of EV meningitis without pleocytosis in adults. Accurate diagnosis using RT-PCR is necessary when meningitis symptoms are prominent during an EV epidemic, and CSF protein levels and pressure are high, even if the CSF WBC count is normal.

Sleep seasonality in alpha-synucleinopathies: A comparative study with non-neurological sleep disorder patients

IntroductionIt is unknown if seasonal variation in daylight affects sleep in patients with alpha-synucleinopathies. Our objectives were to assess month of the year related changes in polysomnography (PSG) data in patients with Parkinson ’s disease (PD), Lewy Body Dementia (LBD) and isolated REM sleep behavior disorder (iRBD). MethodsWe collected PSG data from 64 PD, 30 LBD and 24 iRBD patients attending a sleep laboratory in Lisbon, Portugal, during 10 years. Each was classified according to the month of the year PSG was performed and compared with a control patient with sleep disorder, but no evidence of other neurological disorder, matched for sex, age group and PSG month. The influence of month in PSG data was assessed with mixed linear regression analysis. ResultsIn alpha-synucleinopathies, month showed significant interaction with N2 stage time and percentage (increase from December to April) and N3 time (peak in May). REM sleep percentage increased significantly from Spring to middle Summer. In the control group, there were significant interactions regarding Total Sleep Time and Sleep Efficiency (drop during wintertime), N2 time and REM % (increase in April and May) and Apnea-Hypopnea Index (AHI) (peak in June). There were significant associations between the term group*month and sleep efficiency and AHI, with larger monthly variation in the control group. ConclusionSeasonality had a larger impact in stage architecture in alpha-synucleinopathies, and in total sleep time, sleep efficiency and the severity of OSA in the control group. Different sleep dysfunction mechanisms could explain differences in seasonal variation.

Reassessment of the declines in the largest freshwater lake in China (Poyang Lake): uneven trends, risks and underlying causes

Water level decline in the largest freshwater lake in China (Poyang Lake) has raised grave concerns and continuous debates regarding the proposal of a water control project. Previous hydrologic investigations on the water level decline in Poyang Lake were conducted mostly during recession season and typical dry years and hence lacked the comprehensive view of associated risks and possible spatial heterogeneity of trend during low water level periods. The present study reassessed the long-term trend and regime shift of low water level variations and their associated risks based on hydrological data across multiple stations in Poyang Lake during 1952–2021. The underlying causes of the trends of water level decline were further investigated. Results showed uneven trends and risks of water level variations in different seasons and across different lake regions. The water level of all five hydrological stations in Poyang Lake significantly dropped in the recession season, and the risks of water level decline evidently increased since 2003, which could be largely attributed to the water level drop in the Yangtze River. In terms of the dry season, clear spatial differences of long-term trend of water level were found, with water level in the central and southern lake regions significantly dropping, which was probably caused by dramatic bathymetry undercutting in the central and northern lake regions. In addition, the impacts of topographic changes became significant when water level of Hukou fell below 13.8 and 11.8m for the northern and southern lake regions, respectively. By contrast, water level in the northern lake region showed increasing trends in the dry season. In addition, only the occurrence time of water level under moderate risk significantly advanced for all stations except for Hukou. The present study could provide a full picture of low water level trends, associated risks across different lake regions and underlying causes in Poyang Lake, thus providing insights into adaptive water resources management.

Characteristics and sources of peroxyacetyl nitrate (PAN) in the rural North China Plain: Results from 1-year continuous observations

Peroxyacetyl nitrate (PAN) is an important photochemical pollutant in the troposphere, whereas long-term measurements are scarce in rural areas in North China Plain (NCP), resulting in unclear seasonal variations and sources of PAN in rural NCP. In this study, we conducted a 1-year observation of PAN during 2021-2022 at the rural NCP site. The average concentrations of PAN were 1.10, 0.75, 0.65, and 0.88 ppbv in spring, summer, autumn, and winter, respectively, with a 1-year average of 0.81 ± 0.60 ppbv. Calculations indicate that the loss of PAN through thermal decomposition in summer accounts for 43.2% of the total formed PAN, which is an important reason for the low concentration of PAN in summer. We speculate that since the correlation between PAN and O3 in winter is significantly lower than that in other seasons, the observed regional transport of PAN cannot be ignored in winter. Through budget analysis, regional transport accounted for 12.8% and 55.9% of the observed PAN on the spring and winter pollution days, respectively, which showed that regional transport played key roles during the photochemical pollution of the rural NCP in winter. The potential source contribution function revealed that the transported PAN mainly comes from southern Hebei in spring. In winter, the transported PAN was mainly from Langfang, Hengshui, and southern Beijing. Our findings may aid in understanding PAN variations in different seasons in rural areas and highlight the impact of regional transport on the PAN budget.

A Review of Impacts of the Tibetan Plateau Snow on Climate Variability over East Asia and North America

Snow anomalies over the Tibetan Plateau (TP) have been shown to contribute to the climate variability in the neighboring and remote regions. The present study provides a review of the research progress of studies on the impacts of the TP snow anomalies on the climate over East Asia and North America. This review covers long-term TP snow variations in different seasons and in different regions, interdecadal TP snow changes in different times and their contributions to the interdecadal rainfall changes over East Asia, impacts of TP snow anomalies in different parts and different seasons on East Asian and North America climate variability on interannual time scales, intraseasonal TP snow variations and their impacts on East Asian atmospheric circulation, and interdecadal changes in the relationship of the East Asian rainfall and North American air temperature to the TP snow. The review also includes the atmospheric circulation patterns that link the TP snow to East Asian and North American climate. Discussions are provided for relevant issues of the TP snow impacts.

Environmental variations on physicochemical properties in vasicine content of Adhatoda vasica - An ayurvedic medicinal plant

Adhatoda vasica (Acanthaceae) is a medicinal plant used in traditional formulations for the treatment of various disease conditions. The physicochemical properties fluctuate with the season and in response to stress. To obtain the highest medicinal value it is necessary to collect the plant raw material in the correct season. The present study was aim to evaluate the physiochemical fluctuations in the leaves of A. vasica and the vasicine, an antidiabetic constituent in these leaves. Leaves were collected in every month of a year at different time and places and authentication and standardization was done. The leaves were evaluated for the macroscopic and microscopic evaluation, quantitative microscopy, proximate phytochemical analysis, extractive values in petroleum ether, chloroform, ethyl acetate, ethanol, water, and determination of the concentration of antidiabetic component vasicine. The leaves showed morphological and microscopical variations in different seasons. The phytochemical composition was the same in all seasons however the levels of extractive values fluctuated in response to seasonal variations. Maximum levels of ethanol and water extract were obtained in the winter season also the vasicine concentration was higher in this season.

Overview of PM10, PM2.5 and BC and Their Dependent Relationships with Meteorological Variables in an Urban Area in Northwestern Morocco

At an urban site in Kenitra, Morocco, two aerosol size fractions (PM2.5 and PM10) were sampled for four seasons to characterize the seasonal trends of particulate (PM) and carbonaceous (BC) aerosols. An in-depth statistical analysis of the lag-effects of meteorology on collected data was investigated using uni- and multivariate linear regression analyses. The results revealed significant seasonal trends for PM10, PM2.5, and BC. PM concentrations showed the maximum values in autumn (61.4 ± 24.5 µg/m3 for PM10 and 21.2 ± 8.2 µg/m3 for PM2.5), while the minimum was observed in winter (40.2 ± 17.1 µg/m3) for PM10 and in summer (14.3 ± 3.3 µg/m3) for PM2.5. High BC concentrations were recorded in summer (6.3 ± 4.2 μg/m3, on average). The relative humidity 1–2 days earlier showed a higher negative correlation with the PM concentrations (except in winter), and the temperature 1–3 days earlier showed a negative correlation with the PM2.5 in winter and summer and a positive one with the PM10 in autumn. Wind speed was negatively associated with PM10 on the current day in winter and 3 days earlier in summer. However, diverse effects of wind speed on PM2.5 were observed (negative in summer and positive in spring). These results confirm the important role of meteorology in the formation of urban air pollution with pronounced variations in different seasons.

岩溶区不同土地利用方式下土壤CO2排放模拟研究

PDF HTML阅读 XML下载 导出引用 引用提醒 岩溶区不同土地利用方式下土壤CO2排放模拟研究 DOI: 10.5846/stxb202111223290 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（42072278，42177248）；贵州省科技计划项目（黔科合支撑[2020]4Y013号） Simulation experiment on soil CO2 emission by different land uses in karst area Author: Affiliation: Fund Project: The national natural science foundation of China(42072278,42177248); Guizhou Science and Technology Supporting Plan (No. 2020-4Y013) 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:土地利用变化作为全球气候变化研究的重要内容之一，对土壤CO2的排放具有重要影响。岩溶区石漠化治理过程中植被恢复伴随着土地利用方式的转变，其对土壤CO2排放的影响有待进一步研究。基于控制性实验，以土壤、岩溶含水介质初始条件相同，仅土地利用方式不同的贵州普定沙湾模拟试验场为研究对象，通过1年的土壤CO2浓度和通量数据，研究岩溶区不同土地利用方式下土壤CO2的排放规律及其影响因素。结果表明：（1）土壤CO2的浓度和通量具有明显的季节变化规律，不同季节下的土壤CO2通量呈现昼夜变化规律，温度和降雨影响着土壤CO2的排放，前者可促进排放量，后者可抑制排放量，且不同土地利用方式受影响的程度不同；（2）耕作活动也会影响土壤CO2的排放，耕作使得土壤变得松散，加上岩溶区下伏基岩的溶蚀作用，增加了土壤CO2向含水层的扩散，导致春季耕地表现为负通量；（3）不同土地利用方式下土壤CO2的年排放量不同，具体为草地（897.53 tC km-2 a-1）>灌木地（258.15 tC km-2 a-1）>耕地（207.66 tC km-2 a-1）>裸土地（92.68 tC km-2 a-1），究其原因，主要受不同土地利用下植被生物量和土壤有机碳含量的影响；（4）不同土地利用下的土壤有机碳含量为草地（29.33 g/kg）>灌木地（23.31 g/kg）>耕地（22.08 g/kg）>裸土地（19.00 g/kg），鉴于这些土壤的初始性质相同，研究发现随着土地利用方式的改变，除无植被的裸土地土壤有机碳含量减小外，其余有植被的类型均有增加，且增加的程度和植被覆盖的程度有关。综上，不同土地利用类型可以通过影响上覆植被的生物量和土壤有机碳含量，进而控制土壤CO2的排放，而排放强弱与温度、降雨和耕作活动有关，可以通过土地利用方式的调整来增加土壤有机质含量和土壤储碳。 Abstract:As one of the important parts of global climate change research, land use change plays a significant role in soil CO2 emission. In karst area, vegetation has been restored in the process of rocky desertification control, accompanied by the change of land use, and its impact on soil CO2 emission needs to be further clarified. Based on the controlled experiment, with the same initial conditions of soil and karst aqueous media but different land uses, the Shawan Test Site at Puding, Guizhou was chosen to study the emission law and influencing factors of soil CO2. Through the soil CO2 concentration and flux data in a hydrological year, our results demonstrated that:(1) the soil CO2 concentration and flux showed obviously seasonal variations, and the soil CO2 flux had apparent diurnal variation in different seasons. They were mainly controlled by temperature and rainfall. The former could increase the emission, while the latter could decrease the emission, and the increased or decreased degrees were related to land uses. (2) Farming activities affected the soil CO2 emission as well. Due to the dissolution of the underlying carbonate rock in karst area, farming activities could make the soil loose and increase the diffusion of soil CO2 to the aquifer, resulting in negative soil CO2 flux of cultivated land in spring. (3) The annual emission of soil CO2 under different land uses were grassland (897.53 tC km-2 a-1) > shrub land (258.15 tC km-2 a-1) > cultivated land (207.66 tC km-2 a-1) > bare soil land (92.68 tC km-2 a-1). It was found that they were mainly dominated by vegetation biomass and soil organic carbon content under different land uses. (4) The contents of soil organic carbon were grassland (29.33 g/kg) > shrub land (23.31 g/kg) > cultivated land (22.08 g/kg) > bare soil land (19.00 g/kg). Given the same initial properties of these soils, we found that with the change of land use, except for the soil organic carbon content in non-vegetated bare soil land decreased, the other types increased, and the increased degree was related to the degree of vegetation coverage. Therefore, land use types could control soil CO2 emission by affecting the biomass of overlying vegetation and the soil organic carbon content, and the emission intensity is related to temperature, rainfall process and farming activities. Further, we think that the content of soil organic matter and soil carbon storage could be increased through the adjustment of land use. 参考文献 相似文献 引证文献

Seasonal Characterization and Possible Solutions for Municipal Solid Waste Management in the City of Patna, Bihar, India

The present study aims to characterize the municipal solid waste (MSW) generated in the municipality of Patna, the second-largest city in Eastern India. MSW is heterogeneous and the composition varies with seasons and within the different parts of the city. MSW samples were characterized for the three different seasons Winter (November), Summer (May), and Monsoon (August) to select feasible waste treatment methods. The physical characterization indicates that the major fractions of the MSW were biodegradable (48.83%) and inert (18.26%), which shows variations in different seasons of about ~5%. On a seasonal basis, the chemical characterization of MSW revealed that the moisture content varies between 43.21% to 51.78%, and volatile matter between 20.18% to 29.45%. ash content between 20.20% to 26.23% and fixed carbon between 4.11% to 5.91%. The C/N was found to be between 15.81 to 28.84 and the calorific value lies between 1212 to 2627 kcal.kg-1 during different seasons. The characterization of MSW highlights the virtue of waste segregation at the source and developing an efficient MSW system, including the potential for recycling, composting, anaerobic digestion, and production of refuse-derived fuels (RDFs). The outcomes of the present study will be helpful for Patna Municipal Corporation (PMC) in the planning for implementing suitable waste treatment technologies for integrated solid waste management systems (ISWM).

SEASONAL ENVIRONMENTAL VARIATIONS ON PHYSICOCHEMICAL PROPERTIES OF Aegle marmelos LINN - AN INDIAN AGRICULTURAL PLANT

Aegle marmelos Linn, (Rutaceae) is a medicinal plant used in traditional formulations for the treatment of various disease conditions. The physicochemical properties fluctuate with the season and in response to stress. To obtain the highest medicinal value it is necessary to collect the plant's raw material in the correct season. The present study was aim to evaluate the physiochemical fluctuations in the leaves of Aegle marmelos and the aegelin, an antidiabetic constituent in these leaves. Leaves were collected every month of a year atdifferent time and places and authentication and standardization was done. The leaves wereevaluated for macroscopic and microscopic evaluation, quantitative microscopy, proximate phytochemical analysis, extractive values in petroleum ether, chloroform, ethyl acetate, ethanol, water, and determination of the concentration of antidiabetic component. The leaves showed morphological and microscopical variations in different seasons. The phytochemical composition was the same in all seasons however the levels of extractive values fluctuated in response to seasonal variations. Maximum levels of ethanol and water extract were obtained in the winter season also the angle in concentration was higher in thisseason.

ODONTOGENIC SPACE INFECTION: SEVERITY, CLINICAL AND TREATMENT OUTCOMES WITH SEASONAL VARIATION: 7 – YEARS RETROSPECTIVE HOSPITAL BASED STUDY

Introduction: The aim of the study is to nd a relationship between variations of atmospheric temperature as season changes with indicators reecting the severity of odontogenic space infections, such as day of presentation, isolated microbes, treatment methods, period of drain maintenance and hospital stay, with atmospheric temperature variations in different seasons. This study included 259 patients with Methods: odontogenic infections who were admitted to AMC Dental College and Hospital in Ahmedabad between January 2013 and December 2020. All indicators of odontogenic infections in terms of severity and treatment outcomes are to be considered with seasons. In the summer season, Results: we noticed a statistical correlation between the incidences of odontogenic infections, the early day of presentation, and the longer drain maintenance period. It means that reported cases were more prevalent in high temperatures present during the summer season, with higher clinical incidence and severity. The study result reveals the relationship between Conclusion: atmospheric temperatures as seasons vary with the incidence of odontogenic infection. The high atmospheric temperature in the summer season has higher cases of incidence of infections and drain maintained for more days in terms of severity. Treatment of odontogenic infections poses a s Clinical Implications: ignicant nancial burden for public health service providers. The results of this study can be used to adjust the number of doctors/dental surgeons on duty to reect changing weather conditions. Either way, it serves as an important tool for innovation and creativity.

Optimization of Land Use Regression Modelling of PM2.5 Spatial Variations in Different Seasons across China

Fine particulate matter (PM2.5), one of the main components of haze, is of wide concern for its potential negative health effects. In order to further improve ambient air quality, it is essential to conclude the spatial variability of pollutants by investigating air pollution exposure. We divide China into two parts, north and south, and use a Land Use Regression (LUR) model to extract data including meteorological data, land use factors, and AOD retrievals, and use the machine learning algorithm to optimize the model to achieve predictions of the spatial distribution of near-surface PM2.5 mass concentrations in southern and northern China. We evaluated the seasonal consistency of the models in southern and northern China, and in northern China, we found a better fit with better seasonal consistency for the heating season and annual average model, while in southern China, we did not find a more fitted seasonal phase. The study illustrates that it is feasible to simulate the spatial distribution of PM2.5 mass concentration in large-scale areas based on the LUR model, and the seasonal consistency of the LUR model has been done to some extent.

Quantitative evaluation of runoff variation and its driving forces based on multi-scale separation framework

Study regionThe Xiangjiang River (XJR) basin, China. Study focusOn multiple time scales (annual, quarterly, and monthly), there are few comprehensive and comprehensive quantitative evaluation frameworks for the factors that drive changes in watershed runoff. The focus of this study is to use the Range of Variability Approach (RVA) to quantitatively analyze the changes in the overall hydrological regime of the basin. The Budyko model and the deterministic hydrological process model (ABCD model) were then used to quantitatively separate the factors affecting runoff in the monthly window, and to clarify the differences in the runoff driving force at different time scales. New hydrological insights for the regionAfter the mutation, the runoff of the XJR basin increased by 11%, and the changes in the five groups of hydrological and ecological indicators indicated that the ecological response process of the basin was undergoing negative changes. The contributions of the driving forces on different time scales show significant differences: the climatic factor is the dominant factor of the runoff change on the interannual scale. However, on the seasonal scale, human activities have a greater weight in spring, accounting for 82 % of the total. On a monthly scale, it presents a more complicated situation. Human activities contribute significantly in February, May, and October (60 %, 52 %, and 54 %), while climate factors are the main driving factor in the remaining months (51–170 %).

Seasonal variation of hip fractures in patients with Benign Paroxysmal Positional Vertigo

Introduction: Seasonal variation of benign paroxysmal positional vertigo (BPPV) presentation has been reported, with higher rates of presentation in months associated with times of lower serum vitamin D levels. The purpose of this study was to examine the association between the timing of hip fracture in patients with BPPV. Methods: A retrospective review (2013 to 2019) of adult patients was performed at a tertiary care academic center to identify patients with hip fracture due to ground level fall (ICD-10 code S72) and a previously established diagnosis of vestibular disorder (ICD-10 codes H81-83, A88.1, and R42). Included patients were matched by age and sex to control for patients who had hip fracture without a vestibular diagnosis. Patient charts were reviewed, and demographic and clinical data were extracted related to hip fracture and prior vestibular diagnosis. Groups were subdivided based on whether patients had a hip fracture from January to June versus July to December. Fisher’s exact test was used to evaluate for a difference in seasonal variation between groups. Results: There were 201 patients with vestibular disorders of whom 27 patients carried the diagnosis of BPPV, with a mean age of 80.4 years. The rates of hip fracture among patients with BPPV was higher in the period extending from January to June (63.0%) versus July to December (37.0%), [odds ratio 1.59, 95% CI 0.66-4.00]. The rate of hip fracture was not significantly different between these time periods for the control group (51.7% versus 48.3%) or the vestibular group (53.2% versus 46.8%). Conclusion: These results offer preliminary evidence that, in addition to an increased presentation for BPPV during months associated with decreased serum vitamin D, injuries due to BPPV may be increased as well. The present study is limited by the statistical power afforded by the small number of patients with BPPV and hip fracture that were identified.

High-Throughput Sequencing of Diatom Community, Its Spatial and Temporal Variation and Interrelationships with Physicochemical Factors in Danjiangkou Reservoir, China

Diatoms constitute an important part of the phytoplankton community in lakes and reservoirs and play a significant role in regulating ecological balance. Danjiangkou Reservoir is the water source area of the middle route of China’s South-to-North Water Diversion project. In order to explore the spatial and temporal distribution and know the governing factors of the diatom community, 18srRNA sequencing was carried out from seven sampling sites of the reservoir. At the same time, the concentration of nutrients present in the collected sample water was also determined. The results showed that a total of 51 genera and 96 species were thriving the community of diatoms in Danjiangkou Reservoir. Discostella was dominant in summer and autumn, accounting for 98.84% and 62.71% of the diatom abundance, respectively. Aulacoseira was dominant in spring and winter, accounting for 60.62% and 60.90%, respectively. Discostella and Aulacoseira showed significant differences in seasonal variation (p < 0.05). The colinear network of diatoms changed significantly with the seasons, mainly consisting of Aulacoseira, Discostella, and Stephanodiscus. RDA redundancy analysis showed that water temperature (WT), total nitrogen (TN), NH4+-N, pH, and electrical conductivity (Cond) were the main environmental factors driving the changes in diatom community structure.

Temporal Variation of Meropenem Resistance in E. coli Isolated from Sewage Water in Islamabad, Pakistan.

The WHO has classified carbapenem-resistant Enterobacteriaceae in most critical priority pathogens that pose a threat to human health. The present study investigated the prevalence of meropenem-resistant Escherichia coli (E. coli) in relation to its temporal variation in different seasons along with its resistance markers in sewage water. E. coli was selected on MacConkey agar containing meropenem (3 µg/mL). There were 27% of sites/sewage samples carrying meropenem-resistant E. coli. All E. coli were confirmed through the amplification of the uidA gene. All isolated E. coli were multidrug-resistant (MDR), and among them, 51% were extensively drug-resistant (XDR). An antibiogram determined against 15 antibiotics showed the highest resistance to ampicillin and cefotaxime (98% each) and lowest resistance to fosfomycin (2%). Phylogenetic groups and resistance gene analysis through PCR showed a significant co-occurrence of carbapenemases with extended spectrum beta lactamases (ESBLs), plasmid encoded quinolone, and colistin resistance genes. The higher number of resistance genes in E. coli isolates in community sewage indirectly indicate that these isolates circulate abundantly in the community.

Seasonal variation and plankton physico-chemical characteristics of Omeremaduche River, Abia state, Niger delta, Nigeria

Omeremaduche river was surveyed for Physico-chemical and planktonic characteristics for a period of thirty-four (34) weeks. Three sections of the River were sampled and human activities were considered in the choice of sampling stations. Statistical analysis was done using the Analysis of Variance (ANOVA). The influence of Physico-chemical characteristics on plankton distribution were evaluated using Pearson’s Correlation. The mean values for pH, water-temperature, DO, BOD, phosphate and nitrate during the wet season were 6.91, 27.3, 5.86mg/l, 7.24mg/l, 0.38 and 4.18 respectively, while mean values of the same characteristics during the dry season were 6.68, 26.8, 7.22mg/l, 5.44mg/l, 0.25mg/l and 3.09mg/l. There was a significant difference in seasonal variation in DO, BOD, Nitrate and Phosphate, while there was no significant difference in pH and Water-temperature. The dry season variables were more favourable to plankton survival. Phytoplankton was characterized by four (4) phyla namely, Bacillariophyceae, Chlorophyceae, Euglenophyceae and Chrysophyceae while two (2) phyla Cladocera and Rhizopoda, represented the Zooplanktons. Bacillariophyceae recorded the highest number of individual species across the stations. The occurrence of plankton in Station 2, which is the point of dense anthropogenic activities, were less than what was obtained in the other sections. However, increased concentration of nutrients and dissolved oxygen were recorded in Station 3; this might have influenced the high plankton survival in the station. Changes in Physico-chemical characteristics of the River could be responsible for the varied plankton survival rate in the river. The seasonal variation may be attributed to varied rainfall patterns, while the partial variation may be due to the influence of various anthropogenic activities taking place around the river.

Properties of the Vertical Distribution of Diurnal Temperature Variations in Different Seasons in the Black Sea Based on the NEMO Model Data

Properties of the Vertical Distribution of Diurnal Temperature Variations in Different Seasons in the Black Sea Based on the NEMO Model Data