Ethics,communication models,and power in the agricultural community: Thoughts about development communication     

Nancy Brendlinger 《Agriculture and Human Values》1992,9(2):86-94

Third World farmers are faced with development projects that foster one-way information flows from the government or organization to the farmers, despite the scholarly and practical interest in participatory development models. This article discusses why development projects do not better support power-sharing and proposes introducing sensemaking methodology into the planning and evaluation stages of agricultural development projects.Participation has been difficult to operationalize for many reasons including that communication models used in development are based on the transmission model of communication in which information is envisioned as a thing external to people and communication is the movement of that information from the source to the audience. Sense-making methodology, however, is based on a constructing model of communication in which information is conceptualized not as external to people but a result of their observing and communicating activity. Communication is a constructing process. And the audience is not the target for messages but active participants in creating information.  相似文献   

超级稻育成者获世界粮食奖--杂种优势遗传基础的发现叩开了利用杂交稻的大门     

Forrest Laws  廖伏明  谢放鸣 《杂交水稻》2005,20(2):64-65

很少有一个人被认为他养活了6 000万人,但袁隆平却从来就不是一个普通的人.  相似文献   

Preliminary evaluation of bacterial soft rot resistance in native Chilean potato clones     

Luigi Ciampi-Panno  Nancy Andrade-Soto 《American Journal of Potato Research》1984,61(2):109-112

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Bayesian variable selection in clustering high-dimensional data with substructure     

Michael D. Swartz  Qianxing Mo  Mary E. Murphy  Joanne R. Lupton  Nancy D. Turner  Mee Young Hong  Marina Vannucci 《Journal of Agricultural, Biological & Environmental Statistics》2008,13(4):407-423

In this article we focus on clustering techniques recently proposed for high-dimensional data that incorporate variable selection and extend them to the modeling of data with a known substructure, such as the structure imposed by an experimental design. Our method essentially approximates the within-group covariance by facilitating clustering without disrupting the groups defined by the experimenter. The method we adopt simultaneously determines which expression patterns are important, and which genes contribute to such patterns. We evaluate performance on simulated data and on microarray data from a colon carcinogenesis study. Selected genes are biologically consistent with current research and provide strong biological validation of the cluster configuration identified by the method.  相似文献   

Influence of Tithonia diversifolia and triple superphosphate on dissolution and effectiveness of phosphate rock in acidic soil     

Isaac Savini  Paul C. Smithson  Nancy K. Karanja  Hideo Yamasaki 《植物养料与土壤学杂志》2006,169(5):593-604

An incubation and a pot experiment were conducted to evaluate the dissolution and agronomic effectiveness of a less reactive phosphate rock, Busumbu soft ore (BPR), in an Oxisol in Kenya. Resin (anion and anion + cation)‐extractable P and sequentially extracted P with 0.5 M NaHCO₃, 0.1 M NaOH, and 1 M HCl were analyzed. Dissolution was determined from the increase in anion resin (AER)–, NaHCO₃‐, and NaOH‐extractable P in soil amended with PR compared with the control soil. Where P was applied, resin P significantly increased above the no‐P treatment. Busumbu‐PR solubility was low and did not increase significantly in 16 weeks. Anion + cation (ACER)‐extractable P was generally greater than AER‐P. The difference was greater for PR than for triple superphosphate (TSP). The ACER extraction may be a better estimate of plant P availability, particularly when poorly soluble P sources are used. Addition of P fertilizers alone or in combination with Tithonia diversifolia (TSP, BPR, TSP + Tithonia, and BPR + Tithonia) increased the concentration of labile inorganic P pools (NaHCO₃‐ and NaOH‐P_i). Cumulative evolved CO₂ was significantly correlated with cumulative N mineralized from Tithonia (r, 0.51, p < 0.05). Decrease in pH caused NH ‐N accumulation while NO ‐N remained low where Tithonia was incorporated at all sampling times. However, when pH was increased, NH ‐N declined with a corresponding rise in NO ‐N. Tithonia significantly depressed soil exchangeable acidity relative to control with time. A significant increase (p < 0.05) was observed for P uptake but not dry‐mass production in maize where BPR was applied. The variations in yield and P uptake due to source and rates of application were statistically significant. At any given P rate, highest yields were obtained with Tithonia alone. Combination of Busumbu PR with TSP or Tithonia did not enhance the effectiveness of the PR. The poor dissolution and plant P uptake of BPR may be related to the high Fe content in the PR material.  相似文献   

Sorption-desorption of imidacloprid and its metabolites in soil and vadose zone materials     

Papiernik SK  Koskinen WC  Cox L  Rice PJ  Clay SA  Werdin-Pfisterer NR  Norberg KA 《Journal of agricultural and food chemistry》2006,54(21):8163-8170

Sorption-desorption is one of the most important processes affecting the leaching of pesticides through soil because it controls the amount of pesticide available for transport. Subsurface soil properties can significantly affect pesticide transport and the potential for groundwater contamination. This research characterized the sorption-desorption of imidacloprid (1-[(6-chloro-3-pyridinyl)-methyl]-N-nitro-2-imidazolidinimine) and three of its metabolites, 1-[(6-chloro-3-pyridinyl)methyl]-2-imidazolidinone (imidacloprid-urea), 1-[(6-chloro-3-pyridinyl)methyl]-4,5-dihydro-1H-imidazol-2-amine (imidacloprid-guanidine), and 1-[(6-chloro-3-pyridinyl)methyl]-1H-imidazol-2-amine (imidacloprid-guanidine-olefin), as a function of changing soil properties with depth in two profiles extending from the surface to a depth of 1.8 or 8 m. Sorption of each compound was highly variable and hysteretic in all cases. Normalizing the sorption coefficients (K(f)) to the organic carbon or the clay content of the soil did not reduce the variability in sorption coefficients for any compound. These results illustrate the importance of evaluation of the sorption data used to predict potential mobility. Understanding the variability of soil properties and processes as a function of depth is necessary for accurate prediction of pesticide dissipation.  相似文献   

Infection process of <Emphasis Type="Italic">Gilbertella persicaria</Emphasis> in papaya (<Emphasis Type="Italic">Carica papaya</Emphasis> L.) fruits     

Isabel Cruz-Lachica  Isidro Marquez-Zequera  Raul Allende-Molar  Josefina Leon-Felix  Josefa Adriana Sañudo-Barajas  Nancy Ley-Lopez  Raymundo Saul Garcia-Estrada 《Journal of General Plant Pathology》2018,84(5):339-342

Gilbertella persicaria is a pathogenic fungus recently reported as a causative agent of soft rot in papaya fruits. Here the interactions between G. persicaria and papaya fruits was analyzed under laboratory conditions using histological techniques and optical microscopy to elucidate the process of pathogenesis. Healthy and disinfested fruits of papaya cv. Maradol were also inoculated with a suspension of sporangiospores of G. persicaria. Tissue sections were cut, which were subjected to differential staining with safranin-fast green for different times. Sporangiospores presumably adhered to the cuticle of the fruit by 3 h post inoculation (hpi) and germinated by 6 hpi; invasive intracellular hyphae were growing in host cells by 9 hpi. By 15 hpi, fruit epidermis was macerated, presumably by enzymatic activity reported for mucoral fungal species and appeared as a wet-looking lesion on the cuticle. Fruit mesocarp was colonized by 30 hpi, and asexual reproduction structures had formed by 48 hpi. This process of infection and disease development of G. persicaria in papaya fruits corresponds to that used by pathogens with a necrotrophic lifestyle.  相似文献   

The effect of temperature and duration of incubation on the hatching of diapause eggs of Centropages hamatus (Lilljeborg) (Copepoda, Calanoida)     

Soo-Gun Jo  & Nancy H Marcus 《Aquaculture Research》2004,35(5):432-435

Diapause eggs of Centropages hamatus were used to investigate the effect of temperature and duration of incubation on egg hatching. Eggs were incubated for 10, 12, 14, 16, 20, 24, 28, 32, 36 and 40 h at 15°C and 14L–10D. After incubation for the designated period, eggs were transferred to 25°C and monitored periodically to determine egg hatching. Control eggs were incubated solely at 15°C and monitored for egg hatching. The greatest daily hatching success of eggs occurred within 1 or 2 days after transfer from 15°C to 25°C, while the controls required 3–4 days. The cumulative hatching success of eggs was significantly lower than the control, with the exception of eggs held for at least 36 h at 15°C before transfer to 25°C. These results indicate that overall time to hatching of diapause eggs of C. hamatus can be reduced by transferring the eggs to a higher temperature, for example, 25°C, following a minimum period of time (36 h) at reduced temperature, for example, 15°C. Exposure to 15°C for only 10 h does not appear to be sufficient to result in any subsequent hatching at higher temperature.  相似文献