An effective approach to sustainable small-scale irrigation developments in Sub-Saharan Africa     

Michihiko Sakaki  Kiyoshi Koga 《Paddy and Water Environment》2013,11(1-4):1-14

Countries in Sub-Saharan Africa (SSA) that depend on foreign aid once political independence is gained, continue to be affected by changing aid modalities led by aid communities. It has been claimed that previous irrigation programs in SSA have not improved agricultural production as expected, and that the budget for implementation of further irrigation development has then been decreased. As a result, small-scale operations, which are part of participatory integrated rural development (PIRD), have become mainstream in the implementation of irrigation development in SSA. A small-scale irrigation development (SSID) was considered capable of attracting initial investment, required shorter construction periods, was comparatively easy to design, farmers were able to maintain the system themselves, and it had a lesser environmental impact. In general, to achieve a sustainable irrigation scheme, three systems must be established: a “water utilization system”; an “operation and maintenance (O&M) system”; and a “succession system”. This paper discusses SSID in SSA with regard to a number of important factors, i.e., environmental, economic, and social factors, all of which impact on the sustainability of SSID. The progress of low-input, effective, and sustainable irrigation development (LESID) and the impact of changing aid modalities is followed in three countries, Ghana, Malawi, and Tanzania. In addition, the future effective implementation of SSID by way of LESID in other SSA countries is discussed. A self-supported SSID (as employed in Malawi) is currently considered the most appropriate LESID for least developed countries (LDCs) in SSA.  相似文献   

Induction of the Expressions of Antioxidant Enzymes by Luteinizing Hormone in the Bovine Corpus Luteum     

Syota KAWAGUCHI  Ryosuke SAKUMOTO  Kiyoshi OKUDA 《The Journal of reproduction and development》2013,59(3):219-224

Luteoprotective mechanisms of luteinizing hormone (LH) involved in the maintenance of bovine corpus luteum (CL) function have not been completely clarified. Since antioxidant enzymes are well documented as antiapoptotic factors in the CL of many mammals, we hypothesized that the luteoprotective action of LH is mediated by stimulating the local production and action of antioxidant enzymes. To test the above hypothesis, in the present study, we examined the mechanisms involved in the luteoprotective actions of LH. Cultured bovine luteal cells obtained from the CL at the mid-luteal stage (days 8–12 of the estrous cycle) were treated with LH (10 ng/ml), onapristone (OP; a specific progesterone receptor antagonist, 100 μM) and diethyldithiocarbamate [DETC; an inhibitor of superoxide dismutase (SOD), 100 μM] for 24 h. LH in combination with or without OP significantly increased the mRNA and protein expressions of manganese SOD (Mn-SOD) and catalase (CATA) and SOD activity. While LH alone significantly increased the mRNA and protein expressions of SOD containing copper and zinc (Cu,Zn-SOD), OP in combination with or without LH significantly decreased the mRNA and protein expressions of Cu,Zn-SOD. In addition, Cu,Zn-SOD, Mn-SOD and CATA mRNA expressions were higher at the mid luteal phase than the other luteal phases. LH in combination with DETC significantly decreased LH-increased cell viability. The overall results suggest that LH increases cell viability by LH-increased antioxidant enzymes, resulting in maintenance of CL function during the luteal phase in cattle.  相似文献   

Novel prediction method of beer foam stability using protein Z, barley dimeric alpha-amylase inhibitor-1 (BDAI-1) and yeast thioredoxin     

Iimure T  Takoi K  Kaneko T  Kihara M  Hayashi K  Ito K  Sato K  Takeda K 《Journal of agricultural and food chemistry》2008,56(18):8664-8671

Foam stability is an important quality trait of beer. Our previous results of two-dimensional gel electrophoresis (2DE) analyses of beer proteins implied a relationship between barley dimeric alpha-amylase inhibitor-1 (BDAI-1) and beer foam stability as judged by the NIBEM-T analyzer. To develop a novel prediction method of beer foam stability under different conditions of barley cultivar and malt modification, multiple linear regression analysis was applied. The spot intensities of major beer proteins on 2DE gel were quantified and used as explanatory variables. The foam stabilities of 25 beer samples each brewed from malt with different malt modification in one of the three cultivars (cultivars A, B, and C) were explained by the spot intensities of BDAI-1 at the 5% significance level ( r = 0.421). Furthermore, two other major protein spots (b0 and b5) were observed on the 2DE gels of Japanese commercial beer samples with different foam stability. Then, multiple regression for foam stability was calculated using these three spot intensities as explanatory variables. As a result, 72.1% of the beer foam stability in 25 beer samples was explained by a novel multiple regression equation calculated using spot b0 and BDAI-1 as positive explanatory variables and spot b5 as a negative variable. To verify the validity of the multiple regression equation and the explanatory variables, the beer foam stability in practical beer samples was analyzed. As a result, 81.5% of the beer foam stability in 10 Japanese commercial beer samples was also explained by using spot b0 and BDAI-1 as positive explanatory variables and spot b5 as a negative variable. Mass spectrometry analyses followed by database searches revealed that protein spots b0 and b5 were identified as protein Z originated from barley and thioredoxin originated from yeast, respectively. These results confirm that BDAI-1 and protein Z are foam-positive factors and identify yeast thioredoxin as a possible novel foam-negative factor.  相似文献   

利用内部信息的农用自动引导行走车的研究(第2报)——MAP(Map And Planning)系统          下载免费PDF全文

于海业  马成林  张德骏  并河清  村主胜彦  饭田训久 《农业工程学报》1995,11(3):40-44

介绍农用自动引导行走车研究的地图和路径计划系统(MAP系统)。针对农业领域作业的实际情况,建立了农田的环境模型和环境地图,并采用图论的方法开发了路径计划系统,进而构造了路径地图。  相似文献   

Transition of cell numbers in bovine preimplantation embryos: in vivo collected and in vitro produced embryos     

Ushijima H  Akiyama K  Tajima T 《The Journal of reproduction and development》2008,54(4):239-243

The total cell numbers (TCNs) of bovine embryos collected from superovulated donors (VIVO embryos) were counted 0-9 d after ovulation to quantify the developmental process. Using numerical analysis of embryo development, we also compared the developmental process of VIVO embryos, in vitro-fertilized (IVF) embryos and nuclear transfer (NT) embryos obtained from enucleated oocytes and blastomere nuclei. The TCNs of embryos were measured using the air-dry method. Cleavage divisions (CD) of the embryos were obtained using logarithmic transformation of the TCN. The TCN of the VIVO embryos increased significantly (P<0.001) with time. The relationship between the CD of the VIVO embryos at 0-9 d after ovulation and age in days was described by a linear equation with a high correlation (y=1.03x+0.16, r=0.99), showing that CD occurs about once each day for all blastomeres. However, compared to the VIVO embryos, the TCN of the IVF embryos did not increase from 3-4 d nor after 7 d; the TCN of the NT embryos did not increase after 7 d (P>0.05). The results suggest a delay in development at these developmental stages. The slopes of regression lines of the IVF and NT embryos were significantly (P<0.001) smaller, indicating that quantification of the developmental process of VIVO embryos according to TCN and CD would be useful as criteria for numerical evaluation of the developmental process of bovine in vitro produced embryos.  相似文献   

Determination of maturity in male hawksbill turtle <Emphasis Type="Italic">Eretmochelys imbricata</Emphasis> in captivity based on tail elongation and plasma testosterone level     

Masato Kobayashi  Tomohito Shimizu  Koichi Okuzawa  Kiyoshi Soyano  Kenzo Yoseda 《Fisheries Science》2010,76(5):777-784

To determine the sexual maturity of fourteen male wild-caught hawksbill turtles [straight carapace length (SCL) range 63–79 cm] held in captivity, we investigated their hormone levels in blood and morphological characteristics. Male turtles were divided into two groups: five individuals showing mating behavior (group A) and nine individuals not showing mating behavior (group B). Then, seasonal changes of plasma testosterone of both groups were studied. We also tried to determine male maturity based on tail elongation (TE) index, i.e., the ratio of tail length (TL) to SCL. Plasma testosterone level of group A gradually increased during premating and then sharply declined to low levels between mating and postmating seasons. In contrast, that of group B remained low during the experimental periods. The distinct seasonal changes of plasma testosterone levels of groups A and B correlated with their maturity. Furthermore, males were clearly divided into mature and immature based on TE values >0.35 and <0.33, respectively, corresponding to results based on plasma testosterone levels. Our results indicate that TE can be used more conveniently and accurately to determine maturity of male hawksbill turtles in captivity.  相似文献   

Characteristics of a self-assembled fibrillar gel prepared from red stingray collagen     

Inwoo Bae  Kiyoshi Osatomi  Asami Yoshida  Atsuko Yamaguchi  Katsuyasu Tachibana  Tatsuya Oda  Kenji Hara 《Fisheries Science》2009,75(3):765-770

A translucent collagen gel was formed from a transparent acidic solution of red stingray collagen by adjusting to physiological ionic strength and pH in phosphate buffer and then incubating at 25–37°C. During fibril formation from red stingray collagen, the turbidity increased when the NaCl concentration was increased at constant pH and the rate of fibril formation was accelerated by higher pH or lower NaCl concentration. The T _m of red stingray collagen fibrillar gel was estimated as 44.3 ± 3.5°C, which was higher than that of the collagen solution, 33.2°C. In addition, red stingray collagen gel maintained its shape without melting and was suitable for culture of mouse stromal cells at 37°C.  相似文献   

α-Melanocyte-stimulating hormone directly increases the plasma calcitonin level and involves calcium metabolism in goldfish     

Ikari  Takahiro  Kobayashi  Yuki  Kitani  Yoichiro  Sekiguchi  Toshio  Endo  Masato  Kambegawa  Akira  Asahina  Kiyoshi  Hattori  Atsuhiko  Tabuchi  Yoshiaki  Amornsakun  Thumronk  Mizusawa  Kanta  Takahashi  Akiyoshi  Suzuki  Nobuo 《International Aquatic Research》2018,10(3):283-292

International Aquatic Research - The effects of α-melanocyte-stimulating hormone (α-MSH) on calcium metabolism were examined with goldfish. The scales on the left side of goldfish bodies...  相似文献   

Aluminum toxicity of synthetic aluminum–humus complexes derived from non-allophanic and allophanic Andosols and its amelioration with allophanic materials     

Kiyoshi ITO  Tadashi TAKAHASHI  Masami NANZYO 《Soil Science and Plant Nutrition》2009,55(1):35-41

Natural non-allophanic Andosols often show aluminum (Al) toxicity to Al-sensitive plant roots. The significance of Al–humus complexes to Al toxicity has been emphasized. Allophanic Andosols also possess Al–humus complexes, but they rarely show any toxicity. In the present study, using model substances, we tested the toxicity of Al–humus complexes and its amelioration with allophanic materials. We extracted humic substances from the A horizons of a non-allophanic Andosol and an allophanic Andosol using a NaOH solution, and reacted the humic substances and partially neutralized AlCl₃ solution at pH 4. Allophanic material was purified from commercial Kanuma pumice. Plant growth tests were conducted using a medium containing the Al–humus complexes (50 g kg⁻¹), the allophanic material (0, 90, 180 and 360 g kg⁻¹) and perlite. The root growth of barley ( Hordeum vulgare L.) and burdock ( Arctium lappa ) was reduced in the media containing the Al–humus complexes derived from both the non-allophanic and allophanic Andosols when the allophanic material was not added. With the addition of the allophanic materials, particularly in the 360 g kg⁻¹ treatment, the growth of the barley roots was improved markedly. Although the root growth of the burdock tended to improve with allophanic materials, the effect was weaker than that for barley. Monomeric Al in a solution of the medium was not detected (< 0.05 mg L⁻¹) following the addition of 360 g kg⁻¹ of allophanic materials, whereas 0.8–1.7 mg L⁻¹ Al was recorded without the allophanic material.  相似文献   

恒温高温调节对赤点石斑鱼幼鱼的生长、性腺发育以及gnrh、fshβ和lhβ基因表达的影响     

徐文刚  唐永政  张建柏  真鍋颯一郎  征矢野清  邹华锋 《中国水产科学》2021,28(1):19-28

为了解恒定高温对赤点石斑鱼(Epinephelus akaara)生长和繁殖的影响, 以孵化后120~420 日龄的幼鱼为研究对象, 对性腺发育以及与繁殖相关的基因gnrh、fshβ和lhβ表达进行了研究。对照组为自然水温(13.2~27.1 ℃)饲养, 实验组为26 ℃恒温饲养。每隔30 d或40 d采样1次, 比较两组中鱼的体长、体重、性腺指数(GSI)、性腺发育情况以及gnrh、fshβ和lhβ基因表达的差异。结果表明, 从240日龄开始, 实验组鱼的体长和体重均显著高于对照组(P<0.05)。实验结束时, 实验组体长约为对照组的1.3倍, 体重约为对照组的2倍。对照组GSI一直维持在0.25%以下的低值, 实验组GSI在330日龄前处于0.4%以下, 但在360日龄时出现GSI 1%以上的个体。在360、390和420日龄的个体中, 实验组GSI显著高于对照组(P<0.05)。实验结束时, 对照组中未检测到具有卵黄形成期卵母细胞的个体, 但实验组在330、360和390日龄出现了具有卵黄成熟期卵母细胞的个体。对照组和实验组间幼鱼脑中gnrh基因表达在各年龄段均无显著性差异(P>0.05), 但脑垂体中fshβ表达在360、390和420日龄, lhβ在390和420日龄时, 实验组均显著高于对照组(P<0.05)。研究表明, 26 ℃恒温调节不仅能促进赤点石斑鱼幼鱼体长、体重和GSI的增加, 同时也能显著提高脑垂体中fshβ和lhβ基因含量, 从而加速性腺发育成熟。  相似文献