Hydrogen Sulfide and Odor Control in İzmir Bay     

A. Müezzinoğlu  D. Sponza  I. K Ken  N. Alparslan  A. Akyarli  N. Zt Re 《Water, air, and soil pollution》2000,123(1-4):245-257

The city of ?zmir on the Aegean Sea shoreline is suffering from rotten odors emitted by anoxic river mouths. Anaerobic conditions in the shallowest portion of ?zmir Bay due to industrial and domestic wastewaters as well as eutrophication products in this very calm part of the Bay are responsible for this. The inner section of the Bay is becoming shallower with sediments rich in organic matter. Aerobic digestion of organic pollutants is limited by the oxygen input and the warm climate leads to an optimal medium for anaerobic processes when anoxic conditions take over. Anaerobic digestion products are odorous gases among which H₂S with a characteristic pungent odor is most effective in this case. Sulfur containing gases are formed from sulfides and sulfates in the sediment-water interface and are released into the air. Airborne H₂S concentrations are variable as they depend on factors such as high atmospheric diffusion coefficients under changing wind direction and speed, as well as variable such as water depths, organic loadings from rivers, air and water temperatures, sulfate concentrations in sediment and water phases, pH, and Eh. This study aimed to control noxious smells by inhibiting the anaerobic sulfate-reducing bacteria at the sediment surface. To achieve this aim, pH of the sediment-water interface was increased by spreading hydrated lime. Successful lime doses were investigated in laboratory models first and were then tested and applied in the estuary and downstream segment of one of the creeks. Rates of H₂S gas emissions and aqueous H₂S levels were measured. It was noted that waterborne H₂S levels at river mouths were reduced. Odor control efficiencies of 80–96% even after 10 days of lime addition in the field experiments were obtained. Therefore, the results of this study indicated that lime application to the sediment surface is a recommended method in odor control programs.  相似文献   

揭膜时间与施氮量对油菜产量影响的回归分析   总被引：1，自引：0，他引：1  

王忠宇  艾复清  刘垦  付磐石 《湖北农业科学》2006,45(6):722-724

采用二次饱和D-最优回归设计试验方法,研究油菜地膜覆盖栽培的揭膜时间与施氯量对油菜产量的影响.结果表明,揭膜时间、施氮量对油菜产量的影响均表现出先增后降的抛物线曲线,且前者影响大于后者,当控制揭膜时间在油菜移栽后59～63 d,施氮量每公顷254.3～356.3 kg范围内,油菜产量可达到每公顷4 000 kg左右,其最佳组合为栽后61 d揭膜,施氮量每公顷305.3 kg.  相似文献   

Field determination of unsaturated hydraulic conductivity of forest soils   总被引：1，自引：0，他引：1  

Hendrayanto  Ken’ichirou Kosugi  Takahisa Mizuyama 《Journal of Forest Research》1998,3(1):11-17

This study introduces a field method to determine unsaturated hydraulic conductivity which is applicable to sloping terrain with a limited water supply. A single steel ring infiltrometer and an artificial rainfall simulator are used in this method to reduce the amount of water required to attain a steady-state flux condition. Six tensiometers and a time domain reflectometry (TDR) are employed as the soil capillary pressure head and the volumetric soil water content measurement devices, respectively. Water contents measured by the TDR are corrected using a simple calibration method suggested by Hook and Livingston (1996). Unsaturated hydraulic conductivities are computed based on the instantaneous profile method using capillary pressure head and water content changes measured during a drainage process. The proposed method was applied to a forest soil profile in Rokko Mountain range. Results showed that the relationships between the unsaturated hydraulic conductivity and capillary pressure head developed by the proposed method coincide well with those measured by the conventional steady-state laboratory experiment. The proposedin-situ method is the effective simple means to determine unsaturated hydraulic conductivities of forest soils, since this method is enough accurate and consuming less amount of water and time. This research was partly supported by a Grant-in-Aid for Scientific Research (No. 08760149) from the Ministry of Education, Science, Sports, and Culture, Japan.  相似文献   

蚕蛹油等7种油脂对吉富罗非鱼生长、体组成及脂质代谢影响的比较   总被引：2，自引：2，他引：0  

白富瑾  罗莉  黄先智  陈拥军  胡芯  黄旺  林肯 《水产学报》2017,41(2):258-270

为研究蚕蛹油在吉富罗非鱼饲料中应用的可行性,在饲料中分别添加5.0%的蚕蛹油(SPO)、海水鱼油(MFO)、罗非鱼油(TO)、猪油(PL)、鸡油(CO)、亚麻籽油(LO)和大豆油(SO),配制成7种等氮等脂实验饲料,饲喂初始均重为(47.51±0.52)g的实验鱼。每个处理设置3个重复,每个重复放鱼20尾,进行56 d的养殖实验。结果显示,罗非鱼终末均重、增重率和特定生长率均为LO和SO组显著高于SPO和MFO组,与TO、PL和CO组差异不显著。饲料系数SPO组显著高于除MFO组外的其余各组,而蛋白质效率与之相反。摄食量SPO组最低,SO组最高。TO组罗非鱼脏体比、体长/体高和腹脂率均为最低,而肥满度最高。肝体比PL组显著高于除LO组外的其他各组。腹脂率MFO组显著高于除CO组外的其余各组。同其他组相比,SPO可降低罗非鱼全鱼、组织粗脂肪及血清甘油三酯(TG)、葡萄糖和丙二醛的含量;MFO可降低全鱼粗脂肪的含量和提高肝脏乙酰辅酶A羧化酶(ACC)的活性;PL组罗非鱼血清TG和总胆固醇(TC)含量均较低,而肝脏肉碱脂酰转移酶-I和ACC活性均较高;CO组血清TG、TC、低密度脂蛋白胆固醇(LDL-C)含量和谷草转氨酶活性均为最高;LO和SO可显著提高罗非鱼对饲料脂肪的沉积率和全鱼、肌肉粗脂肪的含量,SO还可显著提高血清高密度脂蛋白胆固醇(HDL-C)和降低LDL-C、TC的含量;SPO、LO和SO可分别显著提高罗非鱼肌肉中高不饱和脂肪酸、α-亚麻酸和亚油酸的含量。研究表明,SPO作为吉富罗非鱼饲料的单一脂肪源,虽会影响其生长性能,但具有降体脂、血脂和血糖,保护鱼体健康和优化肌肉脂肪酸组成等优点。  相似文献   

Seroprevalence of antibodies against severe acute respiratory coronavirus 2 (SARS-CoV-2) in household dogs in Japan     

Genta ITO  Yuko GOTO-KOSHINO  Yudai KURODA  Park EUNSIL  Ken MAEDA  Takehisa SOMA  Yasuyuki MOMOI 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2021,83(11):1722

We investigated the seroprevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) among dogs in the Tokyo area via enzyme-linked immunosorbent assay (ELISA) using the spike protein as the target antigen. Plasma samples from 494 household dogs and blood-donor dogs were tested from July 2020 to January 2021. Of these samples, three showed optical densities that were higher than the mean plus two standard deviations of the mean of the negative-control optical densities (ODs). Of these three samples, only the sample with the highest OD by ELISA was confirmed positive by virus neutralization testing. The positive dog presented no SARS-CoV-2-related symptoms. The positivity rate of SARS-CoV-2 infections among dogs in the Tokyo area was approximately 0.2%.  相似文献   

Sustainable intensification of agriculture in Africa     

Antonius G.T. SCHUT  Ken E. GILLER 《农业科学与工程前沿(英文版)》2020,7(4):371-375

Sustainable intensification is a key component of agricultural development in Africa, urgently needed to wean the continent off foreign food supply and to limit agricultural farmland expansion. It is expected that a relatively small fraction of farmers will adopt fertilizer technology, as profits in current economic settings are relatively small while risks are considerable with varying prices and uncertain yield responses. Many smallholders depend on off-farm income and local markets for food supply. Structural adjustments are therefore needed to allow management of larger units of land by trained farmers willing to take this opportunity, while recognizing land right sensitivities. There are large opportunities for African commodity crops to improve food security, including cassava and East African highland banana that strongly respond to fertilizer with limited environmental risks under good management. This requires investments in better functioning markets, local fertilizer production facilities that can produce regional crop blends and cost-efficient distribution networks, providing balanced fertilizers for African farmers.  相似文献   

Improving the accuracy of estimating blood calcium concentration in Holstein cows using electrocardiographic variables     

Megumi ITOH  Yasuhiro NAKAJIMA  Kouki KUWANO  Daisuke MAEDA  Yoshie SAKURAI  Yoshitaka MATSUI  Satoshi KAWAMOTO 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2022,84(2):193

We previously reported the possibility of using the electrocardiogram variable to estimate blood calcium (Ca) concentration in dairy cows based on the strong positive correlation between the blood Ca concentration and the inverse of the corrected ST peak interval (STc⁻¹). To improve the accuracy of the estimation of blood Ca concentration, we investigated the relationship between blood Ca concentration and STc⁻¹ for each postpartum day and available variables other than STc⁻¹. We measured multiple variables (milk yield, calving number, age, body temperature, etc.), including serum total Ca concentration (tCa), blood ionized Ca concentration (iCa) and STc⁻¹ in 462 Holstein cows on days 0, 1, 2, 3, 5, and 7 postpartum. A very high correlation was observed between iCa and tCa. The association between tCa and STc⁻¹ for each postpartum day had a high coefficient of determination of 0.61–0.79 postpartum 0–2 days but decreased after the third day. In the investigation using the data from postpartum days 0–2, STc⁻¹, heart rate interval, calving number, and age were highly correlated with tCa. In addition, a multiple regression equation was obtained with tCa as the objective variable and STc⁻¹ and calving number as explanatory variables. The estimation accuracy was improved as compared with the simple regression equation using only STc⁻¹ as the explanatory variable. This multiple regression equation was used for 11 cows suspected of having hypocalcemia, and it was able to correctly detect cows requiring early treatment, except for one cow.  相似文献   

Diffusion tensor imaging-based quantitative analysis of the spinal cord in Pembroke Welsh Corgis with degenerative myelopathy     

Eiji NAITO  Kohei NAKATA  Hiroki SAKAI  Osamu YAMATO  Md Shafiqul ISLAM  Sadatoshi MAEDA  Hiroaki KAMISHINA 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2022,84(2):199

Canine degenerative myelopathy (DM) is a progressive neurodegenerative disease of the spinal cord. The diagnosis is based on the observation of clinical signs, genetic testing, and exclusion of other spinal cord diseases, and a definitive diagnosis of DM can only be confirmed by postmortem histopathological findings. The aim of this study was to investigate the diagnostic ability of diffusion tensor imaging (DTI) for DM. Eight DM-affected Pembroke Welsh Corgis, thirteen dogs with thoracolumbar intervertebral disk herniation (IVDH), and six healthy control dogs were included. All dogs were scanned using a 3.0-T MRI system. Apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values were calculated for each intervertebral disk level slice between T8–T9 and L2–L3 intervertebral disk levels, and the entire area of the thoracolumbar spinal cord between T8–T9 and L2–L3 intervertebral disk levels (T8–L3 region). The ADC and FA values of the T8–L3 region were significantly lower in the DM group than in the IVDH group. The ADC values for the T8–L3 region had a moderate negative correlation with clinical duration (r_s= −0.723, P=0.043); however, the FA values of other intervertebral disk levels and T8–L3 region had no correlation with clinical durations. The measurement of DTI indices can be used to quantitatively assess neurodegeneration and may have diagnostic value for DM. In particular, the ADC value of the T8–L3 region may aid in making a non-invasive premortem diagnosis of DM.  相似文献