39 research outputs found

    Experimental investigations of competition and allelopathy in herbaceous plants.

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    This thesis consists of two parts. Part I describes field investigations carried out to examine the characteristics of the major species present in the herb layer in a range of perennial communities established at various sites in the Sheffield region. At each site quantitative measurements of seasonal changes in shoot biomass were conducted in association with analyses of soil mineral nutrient status and bioassays designed to allow seasonal release of phytotoxins to be detected. From the results of these studies it would appear that dominance in relatively productive and undisturbed vegetation is strongly associated with the capacity to develop a large summer peak in shoot biomass. This pattern is evident in the widely successful grass, Holaus lanatus, although in this species the size of the summer peak was found to vary considerably from year to year. From soil analyses it was apparent that mineral nutrient status plays an important part in determining the types of phenology represented in the vegetation. The results of bioassays conducted on various soils suggested the release of toxins from certain plants. At two sites toxicity appeared to be related to the rapid efflux of organic solutes from deciduous tree litter. Toxic effects were also detected in an area of derelict grassland colonized by Holcaus Lanatus. Evidence of autotoxicity in H. lanatus was obtained from the field and in a garden experiment. The experimental studies in Part II involved attempts to measure the effects of toxin production and competition by H. lanatus upon the growth of species with which H. lanatus is frequently associated in the field. In an attempt to manipulate the vigour and competitive ability of H. lanatus, studies were conducted to measure the influence of temperature and mineral nutrient supply upon a mixed sward. The results revealed a strong capacity in H. lanatus to suppress the vigour of H. lanatus and this ability was only marginally affected by variation in temperature and clipping regime. The results of the laboratory experiments supported the field evidence of toxic effects originating from H. lanatus. A technique was developed which effectively distinguishes between allelopathy and effects resulting from the depletion of mineral nutrients in the soil solution

    Operations De Lotissement Dans l’Arrondissement d’Akassato : Enjeux, Pratiques et Defis

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    RésuméLe foncier au Benin a été pour la plupart du temps, l’objet de plusieurs discordes entre les habitants elle-même d’une part et les autorités locales d’autres part. La présence recherche s’intéresse à la problématique des opérations de lotissement dans l’Arrondissement d’Akassato.Pour atteindre les objectifs fixés dans le cadre de cette recherche, des investigations ont été faites à partir de la collecte des données et informations aux moyens de la recherche documentaire, des observations directes sur le terrain, des entretiens et enquêtes auprès de 136 personnes. Les résultats obtenus ont été analysés à l’aide du modèle SWOT. Il ressort des résultats que l’achat est le mode le plus adopté par les populations avec 68 %  tandis que l’héritage et la location sont respectivement de 24 % et 8 %. Tous les villages de l’Arrondissement d’Akassato sont concernés par les opérations de lotissement. Au total, 3575 superficies sont en cours de lotissement. De plus, le manque de transparence, le détournement des terres par les géomètres avec la complicité des membres du comité de lotissement caractérisent ces opérations de lotissement qui laissent planer le spectre d’une remise en cause permanent des travaux. La mise en place des Association d’Intérêt Foncier (AIF) et le respect des lois qui régissent le foncier par les acteurs et les populations permettront une bonne gestion du foncier en général et des lotissements en particulier dans l’Arrondissement d’Akassato.Mots clés : Akassato, lotissement, foncier, conflits fonciers AbstractLand in Benin has for the most part been the subject of several disagreements between the inhabitants themselves on the one hand and the local authorities on the other hand. The research presence is interested in the problem of subdivision operations in the Arrondissement of Akassato.To achieve the objectives set within the framework of this research, investigations were made from the collection of data and information by means of documentary research, direct observations in the field, interviews and surveys with 136 people. The results obtained were analyzed using the SWOT model.The results show that buying is the mode most adopted by the population with 68%, while inheriting and renting are respectively 24% and 8%. All the villages of the Akassato District are affected by the subdivision operations. In total, 3,575 areas are being subdivided. In addition, the lack of transparency, the misappropriation of land by surveyors with the complicity of members of the subdivision committee characterize these subdivision operations which raise the specter of a permanent questioning of the work. The establishment of Associations of Land Interest (AIF) and compliance with the laws governing land by actors and populations will allow good management of land in general and housing estates in particular in the Arrondissement of Akassato.Keywords: Akassato, subdivision, land, land dispute

    Experimental investigations of competition and allelopathy in herbaceous plants.

    Get PDF
    This thesis consists of two parts. Part I describes field investigations carried out to examine the characteristics of the major species present in the herb layer in a range of perennial communities established at various sites in the Sheffield region. At each site quantitative measurements of seasonal changes in shoot biomass were conducted in association with analyses of soil mineral nutrient status and bioassays designed to allow seasonal release of phytotoxins to be detected. From the results of these studies it would appear that dominance in relatively productive and undisturbed vegetation is strongly associated with the capacity to develop a large summer peak in shoot biomass. This pattern is evident in the widely successful grass, Holaus lanatus, although in this species the size of the summer peak was found to vary considerably from year to year. From soil analyses it was apparent that mineral nutrient status plays an important part in determining the types of phenology represented in the vegetation. The results of bioassays conducted on various soils suggested the release of toxins from certain plants. At two sites toxicity appeared to be related to the rapid efflux of organic solutes from deciduous tree litter. Toxic effects were also detected in an area of derelict grassland colonized by Holcaus Lanatus. Evidence of autotoxicity in H. lanatus was obtained from the field and in a garden experiment. The experimental studies in Part II involved attempts to measure the effects of toxin production and competition by H. lanatus upon the growth of species with which H. lanatus is frequently associated in the field. In an attempt to manipulate the vigour and competitive ability of H. lanatus, studies were conducted to measure the influence of temperature and mineral nutrient supply upon a mixed sward. The results revealed a strong capacity in H. lanatus to suppress the vigour of H. lanatus and this ability was only marginally affected by variation in temperature and clipping regime. The results of the laboratory experiments supported the field evidence of toxic effects originating from H. lanatus. A technique was developed which effectively distinguishes between allelopathy and effects resulting from the depletion of mineral nutrients in the soil solution

    Effect of Age and Periods of Rigor Mortis on Quality of Sarcoplasmic Proteins Separation from Meat’s Protein by Using Electrophoresis Technique

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    We were separated sarcoplasmic proteins from beef meats on 12 and 28 months ,mutton meats on 6 and 12 months and  chicken meats on 25 and 40 days  on rigor mortis stage and after rigor mortis stage by using  electrophoresis technique. The results showed the following: Sarcoplasmic proteins differ on all types of meats below number of bands separation from it’s as differ of age of animal and stage of rigor mortis ,On beef meat proteins showed presence of 10 and 8  bands on 12 and 28 months on stage of rigor-post  mortis the bands separation from sarcoplasmic, On the mutton meat we separation 10 bands of sarcoplasmic proteins on  6 and 12 months on stage of rigor-post mortis, We found 11 bands of sarcoplasmic proteinson on chicken meats on 25 and 40 days respectively.The band of  phosphorylase b (PHb) and phosphorylase b kinase (PHbK) enzymes  showed as one big pale band,while phosphor glucomutase)  PGM), pyruvate kinase (PK), phosphoglucose isomerase) PGI), enolase (EN),  creatine kinase) CK), phosphoglycerate kinase (PGAK), aldolase  (ALD), glyceraldehyde phosphate dehydrogenase (GAPDH), lactate  dehydrogenase (LDH), phosphoglycerate mutase) PGAM), triosephosphate isomerase (TPI) and myoglobin ( Mb ) showed as thin and pale bands. Keywords: Beef meat , mutton meat, chicken meat,  meat’s protein, sarcoplasmic proteins, electrophoresis, rigor morti

    Darfuri village bombing

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    Drawing of a military helicopter bombing a village home. A military truck is also shown.https://digitalcommons.usf.edu/darfuri_drawings/1081/thumbnail.jp
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