Genotypic Diversity Affects Age Structure of Tiller and Rhizome of Leymus chinensis Population,But Not Age Structure of Bud

The effect of genotypic diversity on the age structure and bud bank of the Leymus chinensis population has not yet been demonstrated.This experiment was designed to study the age structure of the tiller,rhizome,and bud of L.chinensis at genotypic diversity levels of 1,2,4,8,and 12.A total of 64 communities were established in this experiment,following the principle of randomized block experimental design.The results indicated that genotypic diversity had a significant or obviously significant effect on the cumulative length of rhizomes of 2a and 4a,dry matter accumulation of rhizomes of 1a and 2a,tiller number of 1a,tiller productivity of 3a,but had no significant effect age structure of buds.As the levels of genotypic diversity increased,the proportion of the cumulative length of rhizomes with 4a decreased and then increased,and dry matter accumulation of rhizomes with 1a and 2a gradually increased while the number of tillers with 1a gradually decreased,when the gradient of genotypic diversity increased.At the 1,2,4,8,and 12 genotype diversity levels,the number of tillers,the cumulative length of rhizomes,and dry matter accumulation in rhizomes and buds were all age structures of expanding type.However,tiller productivity was an expanding or stable age structure at levels of 1,2,4,8 genotypic diversity,while it was a declining age structure at the 12 genotype diversity gradient.An appropriate genotypic diversity is conducive to maintaining the growth and stability of the age structure of L.chinensis population,but too high a gradient of genotypic diversity can have a negative impact on the population age structure.This study provided that an appropriate number of genotypic diversity contributes to the stability of the population.

Allelopathic Effect of Seed and Leaf Aqueous Extracts of <i>Datura stramonium</i>on Leaf Chlorophyll Content, Shoot and Root Elongation of <i>Cenchrus ciliaris</i>and <i>Neonotonia wightii</i>

Pot experiment was carried out to determine the allelopathic effects of Datura?stramonium on leaf chlorophyll content, root and shoot elongation, fresh and dry weight of two wild plant species: Cenchrus ciliaris and Neonotonia wightii. Different concentrations (0%, 25%, 50%, 75% and 100%) from seed and leaf extracts of D. stramonium were used to investigate the allelopathic effects of D. stramonium on growth of tested species.?The total chlorophyll content of N. wightii was significantly reduced in all plants treated with both aqueous seed and leaf extracts of D. stramonium. In C. ciliaris, the total chlorophyll content was also significantly reduced for those plants treated with aqueous seed extract and leaf extract from D. stramonium. Relative to the control treatments, there was greater reduction in root and shoot length which was observed in higher concentrations of aqueous seed and leaf extracts. Fresh and dry weight of tested species significantly decreased after being treated with both seed and leaf aqueous extracts of D. stramonium. It was found that the allelopathic effect of aqueous seed and leaf extracts from D. stramonium on tested species was concentration-dependent. The inhibitory effects on all tested species increased as the concentration of both extracts increased from 0% to 100%. This study concluded that aqueous seed and leaf extract of D. stramonium have allelopathic effects on leaf chlorophyll content, root and shoot length, fresh and dry weight of grass (C. ciliaris) and legume (N. wightii) species.

Influence of <i>Bradyrhizobium japonicum</i>and Phosphorus on Micronutrient Uptake in Cowpea. A Case Study of Zinc (Zn), Iron (Fe), Copper (Cu) and Manganese (Mn)

The field and screen house experiments were carried out in the 2013 cropping season to assess the effects of B. japonicum inoculation and phosphorus supplementation on the uptake of micronutrients in the cowpea. The experiment was laid out in a split plot design where the main plots comprised two inoculation treatments (with and without B. japonicum inoculation) and sub plots included four different levels of phosphorus (0, 20, 40, and 80 kg P/ha). The results showed a significant improvement in the uptake of micronutrients in the B. japonicum inoculated treatments over the control. Phosphorus supplementation (40 kg P/ha) also showed a significant increase in the uptake of some micronutrients while decreasing the uptake of Zn in some plant organs. There was also a significant interaction between B. japonicum inoculation and phosphorus in the root uptake of Zn for the field experiment.

Isolation and Characterization of Nitrogen Fixing Rhizobia from Cultivated and Uncultivated Soils of Northern Tanzania

Soil bacteria1 called rhizobia are gram-negative capable to colonize the soil immediately surrounding roots under the influence of the plant “rhizosphere” and reduce atmospheric nitrogen into the form available to plants through nitrogen fixation process. Nitrogen is the most limiting and supplied nutrient to most plants, and the determinant of plant growth. Legumes differ with most plants because they have access to nitrogen from both mineral and symbiotic sources. Small-scale farmers who are the major legume producers in Africa rarely apply fertilizers during legume production. Hence, the crop is largely dependent on fixed nitrogen from native nitrogen fixers. Isolation of rhizobia for legume production has been given a little attention in Africa due to inadequate research or negligence of researchers and unawareness of its potential in legume production as well as lack of an intention from skilled personnel to popularize the technology. Evaluation of effectiveness of isolated rhizobia is essential for inoculants preparation, host specificity recommendation and symbiotic effectiveness. The isolation, determination of their population in the soil and assessing factors affecting their population and testing the effectiveness of native nitrogen fixers with respect to right trap host crop are given a special attention in this review.

Computational Fluid Dynamics Analysis of Shroud Design on Hemodynamic Performance and Blood Damage in a Centrifugal Blood Pump

Patients with extracorporeal membrane oxygenation still suffer from high rates of complication that linked to the flow field within the blood pump.So it is essential to optimise the geometry of the pump.The specification of shroud design is arguably the necessary design parameter in the centrifugal pump.However,the hemodynamic performances of the different shroud designs have not been studied extensively.In this study,ten different shroud designs were made and divided into two groups as the different covering locations(A:Covering the blade leading edge,B:Covering the blade trailing edge).In every group,six shroud designs with the covering proportions of 0,1/5,2/5,3/5,4/5,1 were made.Detailed computational fluid dynamics(CFD)analyses were performed to investigate their effects on hemodynamics and hydraulic performance at the constant flow condition(4000 rpm,5 L/min).The percentage volumes of the scalar shear stress in specific threshold(τ<1 Pa:Thrombosis,τ>9 Pa:the destruction of von Willebrand factor,τ>50 Pa:Platelet activation,τ>150 Pa:Break of red blood)were used to compare the blood damage of the different shroud designs.Also,the modified index of hemolysis(MIH)were calculated based on a Eulerian approach for different pumps.CFD simulations predicted an increase in the pump head,hydraulic efficiency,a fraction of fluid volume with scalar shear stress values above a threshold(9 Pa,50 Pa,150 Pa)and MIH with increasing shroud covering proportions from 0 to 1 in the same covering location.Also,these above results were higher in group B than group A.This means that the risks of the hemolysis,thrombosis and bleeding increased as the rise of the covering proportion and they were higher in the pump whose shroud covers the blade trailing edge.

Effects of <i>Bradyrhizobium japonicum</i>Inoculation and Supplementation with Phosphorus on Macronutrients Uptake in Cowpea (<i>Vigna unguiculata</i>(L.) Walp)

The current study was conducted to assess the effects of phosphorus supplementation and Bradyrhizobium japonicum inoculation on the availability and uptake of N, P, K, Mg, Ca and Na on cowpea. The experiment was laid out in a split plot design where the main plots comprised two inoculation levels (with and without inoculation of B. japonicum ) and sub plots contained four different levels of phosphorus (0, 20, 40, and 80 kg P/ha). The results indicated that B. japonicum inoculation and phosphorus supplementation significantly improved the uptake of N, P, K, Mg, Ca and Na in different cowpea tissues such as roots, pods, shoots, and whole plant relative to the control. The results also indicated that there was a significant interaction of B. japonicum and phosphorus on the uptake of sodium in the roots and whole cowpea plant in the screen house. Rhizobia inoculation and supplementation of phosphorus at 40 kg P/ha resulted in the improved uptake of the most elements over other treatments tested.

The Hemodynamic Study on the Effects of Entry Tear and Coverage in Aortic Dissection

In this work,the hemodynamic effects of the type-A aortic dissection in different entry and covering entry tear positions were mainly studied.It provides a new method or idea in the field of the aortic dissection hemodynamics,and it is of profound significance to provide basic theoretical research on the development of aortic dissection in the aspect of clinical judgment.Two type-A aortic dissection models with different entry tear positions(Model 1:The entry tear was located at the entrance of the ascending aorta,Model 2:The entry tear was located at the starting position of the descending aorta)were reconstructed according to the computed tomography(CT)images of the patients.In our study,the thoracic aortic endovascular repair was simulated by covering the entry tear(Model 3).To clarify the hemodynamic effects of entry tear and coverage,the comparative study on the true lumen(TL)and false lumen(FL)blood flow patterns of three models were carried out numerically.The velocity vector,flow ratio,pressure,time-averaged wall shear stress(TAWSS)and relative residence time(RRT)were calculated to evaluate the hemodynamic changes.The results of this work indicated that(I)the velocity of entry tear at the aorta entrance was higher;(II)The helical development of the TL and FL might be related to the helical nature of aortic arch;(III)The blood flow which passing the FL of Model 1,Model 2 and Model 3 in one cardiac cycle were approximately 26.63%,13.39%and 1%,respectively;(IV)The difference in intima wall pressure of the TL and FL were showed a strong pulsation;(V)The TAWSS distribution in TL and FL were completely different(the TAWSS in TL intima>8 Pa,the TAWSS in FL intima<4 Pa).In brief,the aortic morphology and location of the entry tear were found to have a significant effect on the hemodynamics of the aortic dissection.In addition,the CFD method is used to obtain multi-dimensional hemodynamic information such as velocity field,pressure,TAWSS and RRT,which can help clinicians better understand the development of type-A aortic dissection and provide a theoretical basis for clinical treatment.

Prospects of Biotechnological Approaches for Propagation and Improvement of Threatened African Sandalwood (<i>Osyris lanceolata</i>Hochst. &Steud.)

The African Sandalwood plant (Osyris lanceolata ) is a threatened shrub or a small hemi-parasitic tree endemic to East Africa and South African regions, which is being severely affected by uprooting for oil extraction, poor natural regeneration, phenological structures (dioecious), medicinal values, lack of sexual recruitment, habitat loss, anthropogenic and climate factors. It has been found that through application of in situ conservation of natural trees with respect to rapid human population growth, the available natural strands of valuable plants such as African sandalwood have not been able to meet the demands of the people in world specifically developing countries. However, advances in plant biotechnology provide new options for collection, multiplication and short- to long-term conservation of Osyris lanceolata species, using in vitro culture techniques. Different aspects of biotechnological applications can be extensively used to reduce the risk of extinction of this valuable plant species and to improve the quality and quantity of essential oils produced by it. Therefore, tissue culture appears to be a promising approach for the propagation and conservation of African sandalwood plant.

Yield and Fiscal Benefits of <i>Rhizobium</i>Inoculation Supplemented with Phosphorus (P) and Potassium (K) in Climbing Beans (<i>Phaseolus vulgaris</i>L.) Grown in Northern Tanzania

Both field and green house experiments were intended to investigate and evaluate the outcome of rhizobial inoculation supplemented with P and K on climbing beans production in northern Tanzania. The results obtained indicated that, inoculation using Rhizobium inoculants supplemented with fertilizers significantly (p ≤ 0.001) improved both vegetative and yield parameters of climbing beans varieties compared with control treatment. The economic analysis in rhizobium alone revealed a profit of US$ 2350 compared with control treatment with US$ 1558 profit, which was finally reflected in higher percentage increase over control and higher marginal rate of return (MRR). Thus, the use of Rhizobium inoculants supplemented with P and K increased climbing beans yield and the economic analysis performed based on total revenue and variable costs reflected an improvement in economic well being of a small hold farmer of northern Tanzania.

Extrapolations on the Use of Rhizobium Inoculants Supplemented with Phosphorus (P) and Potassium (K) on Growth and Nutrition of Legumes

Land scarcity and poor farming management practices has resulted in to intensive agriculture which rendered most of the soil in sub Saharan Africa depleted in essential plant nutrients. High prices of chemical fertilizer are crucial bottleneck toward increasing production of legumes and other food crops in most countries found in sub-Saharan Africa. Nitrogen, phosphorus and potas-sium are among the most limiting nutrients for plant growth as they play different but crucial roles in the plant physiological processes. These macronutrients are fundamental components of cell building blocks including genes and chromosomes. This review intend to show the vital roles played by rhizobial inoculants supplemented with phosphorus and potassium in enhancing growth, yield, photosynthesis, nodulation, nutrient uptake and nitrogen fixation of legumes.

Allelopathic Effect of Aqueous Extract of Argemone mexicana L on Germination and Growth of Brachiaria dictyoneura L and Clitoria ternatea L

The present study was conducted in the laboratory to investigate the allelopathic effect of Mexican poppy (Argemone mexicana L.) to the germination and growth parameters of two native species Brachiaria dictyoneura L and Clitoria ternatea L. Different concentrations of leaf and seed aqueous extracts from Argemone mexicana (0%, 25%, 50%, 75% and 100%) were evaluated. Results showed that seed germination, root length, shoot length, seedling length, fresh weight and dry weight of B. dictyoneura and C. ternatea seedlings were significantly reduced by leaf and seed extracts compared with control treatments. Roots were more affected than shoots;and leaf extract was more suppressive than seed extracts. From the results, it is concluded that leaf and seed extracts have some allelochemicals with inhibitory effect on germination and growth of the tested plant species.

Prospective Bioactive Compounds from <i>Vernonia amygdalina, Lippia javanica, Dysphania ambrosioides</i>and <i>Tithonia diversifolia</i>in Controlling Legume Insect Pests

Synthetic insecticides are widely known to control insect pest, but due to high operational cost, environmental pollution, toxicity to humans, harmful effect on non-target organisms and the development of insect resistance to this products, have created the need for developing alternative such as those involving the use of botanical pesticides to control insect pest. Bioactive compounds derived from plant could be an alternative source for insect pest control because they constitute a rich source of natural chemicals. This review aims to explore the potential of plant bioactive compounds from Vernonia amygdalina, Lippia javanica, Dysphania ambrosioides and Tithonia diversifolia as a low-cost, safe and environmentally friendly means of controlling insect pests in legumes.

Allelopathic Effects of <i>Argemone mexicana</i>to Growth of Native Plant Species

Argemone mexicana is known to have significant effects on cultivated agricultural fields. However, there is little information about allelopathic effect of A. mexicana on the growth of wild plant species such as those found in wildlife protected areas. This review presents evidence that allelochemicals present in A. mexicana may affect the overall growth of other plant species.

The Hemodynamic Comparative Study Between Pulsatile and Non-Pulsatile VA ECMO:A Primary Numerical Study

Although pulsatile ECMO,as novel kinds of ECMO,has been attracted more and more attention,the differences of the hemodynamic effects of the pulsatile ECMO on the aorta,the cerebral perfusion,and left ventricular work were still under-investigated.The aim of this study was to clarify the hemodynamic differences of the cardiovascular system between the pulsatile and non-pulsatile VA ECMO.In this study,three ECMO support modes,named as“constant flow mode”,“co-pulse mode”and“counter pulse mode”,were designed.The computational fluid dynamics(CFD)study was carried out.The distribution of the oxygenated blood,the blood velocity vector,the oscillatory shear index(OSI),the relative residence time(RRT),the left ventricular external work(EW),the equivalent left ventricular afterload(EAL)and the energy loss of cardiovascular system(EL)were calculated to compare the hemodynamic differences.The simulation results demonstrate that the oxygenated blood under co-pulse mode was easier to perfuse into the three braches vessels than that under both other modes.In addition,the ECMO under counter pulse mode could also achieve lowest RRT(constant flow mode 220 vs.co-pulse mode 132 vs.counter pulse mode 93).Similarly,the ECMO under counter pulse mode could significantly reduce the left ventricular external work(co-pulse mode 1.51 w vs.constant flow mode 1.44 w and counter pulse mode 1.30 w),left ventricular afterload(constant flow mode 1.03 mmHg·s/ml vs.co-pulse mode 1.67 mmHg·s/ml vs.counter pulse mode 0.82 mmHg·s/ml)and energy loss of arterial system(constant flow mode 0.18 w vs.co-pulse mode 0.50 w vs.counter pulse mode 0.16 w).In short,the ECMO under counter pulse mode could have advantages to the left ventricular unloading.In contrast,the ECMO under co-pulse mode has more benefit to cerebral oxygen perfusion.

Alpha-synuclein gene structure,evolution,and protein aggregation

α-synuclein, a member of the synuclein family, is predominately expressed in brain tissues, where it is the major component of Lewy bodies, the major hallmark of Parkinson＇s disease. We analyzed the phylogenetics, gene structure, and effects of different forms of α-synuclein on in vitro protein aggregation. The synuclein phylogenetic tree showed that sequences could be classified into α, β, and y protein groups. The orthologous gene α-, β- and y-synuclein showed similar evolutionary distance to the paralogous gene α-, β- and y-synuclein. Bioinformatics analysis suggests that the amino-acid sequence of human a-synuclein can be divided into three regions： N-terminal amphipathic region （1-60）, central hydrophobic non-amyloid beta component segment （61-95）, and the C-terminal acidic part （96-140）. The mutant site of A30P is at the second exon of α-synuclein, whereas E46K is located at the third exon of α-synuclein. α-synuclein alternative splicing results in four isomers, and five exons, all of which participate in protein coding, comprising 140 amino acids to produce the major α-synuclein in vivo. The three α-synuclein isoforms are products of alternative splicing, α-synuclein 126, 112 and 98. We also review the genetic and cellular factors that affect the aggregation of α-synuclein and compounds that inhibit aggregation. A better understanding of α-synuclein sequences, structure, and function may allow better targeted therapy and diagnosis of α-synuclein in Parkinson＇s disease and other neurodegenerative diseases.

Investigating connectional characteristics of Motor Cortex network

To understand the connectivity of cerebral cor-tex, especially the spatial and temporal pattern of movement, functional magnetic resonance imaging (fMRI) during subjects performing finger key presses was used to extract functional networks and then investigated their character-istics. Motor cortex networks were constructed with activation areas obtained with statistical analysis as vertexes and correlation coefficients of fMRI time series as linking strength. The equivalent non-motor cortex networks were constructed with certain distance rules. The graphic and dynamical measures of motor cor-tex networks and non-motor cortex networks were calculated, which shows the motor cortex networks are more compact, having higher sta-tistical independence and integration than the non-motor cortex networks. It indicates the motor cortex networks are more appropriate for information diffusion.

Patterns of tsetse abundance and trypanosome infection rates among habitats of surveyed villages in Maasai steppe of northern Tanzania

Background:Changes of land cover modify the characteristics of habitat,host-vector interaction and consequently infection rates of disease causing agents.In this paper,we report variations in tsetse distribution patterns,abundance and infection rates in relation to habitat types and age in the Maasai Steppe of northern Tanzania.In Africa,Tsetse-transmitted trypanosomiasis negatively impacted human life where about 40 million people are at risk of contracting the disease with dramatic socio-economical consequences,for instance,loss of livestock,animal productivity,and manpower.Methods:We trapped tsetse flies in dry and wet seasons between October 2014 and May 2015 in selected habitats across four villages:Emboreet,Loiborsireet,Kimotorok and Oltukai adjacent to protected areas.Data collected include number and species of tsetse flies caught in baited traps,PCR identification of trypanosome species and extraction of monitored Normalized Difference Vegetation Index(NDVI)data from Moderate Resolution Imaging Spectrometer(MODIS).Results:Our findings demonstrate the variation of tsetse fly species abundance and infection rates among habitats in surveyed villages in relation to NDVI and host abundance.Results have shown higher tsetse fly abundance in Acacia-swampy ecotone and riverine habitats for Emboreet and other villages,respectively.Tsetse abundance was inconsistent among habitats in different villages.Emboreet was highly infested with Glossina swynnertoni(68%)in ecotone and swampy habitats followed by G.morsitans(28%)and G.pallidipes(4%)in riverine habitat.In the remaining villages,the dominant tsetse fly species by 95%was G.pallidipes in all habitats.Trypanosoma vivax was the most prevalent species in all infected flies(95%)with few observations of co-infections(with T.congolense or T.brucei).Conclusions:The findings of this study provide a framework to mapping hotspots of tsetse infestation and trypanosomiasis infection and enhance the communities to plan for effective control of trypanosomiasis.

Carrot-Weed: A Noxious Plant That Threatens Biodiversity in Africa

Carrot-weed (Parthenium hysterophorous L.) is a flowering plant of the Asteraceae family (tribe: Heliantheae). The weed became famous due to its notorious invasive role in the environment and agricultural fields. The plant has arisen as the seventh most disturbing weed globally. In Africa, the weed is spreading very fast and information on its biology, impact, and management is scarce. Therefore, this review provides general information about the carrot weed’s current distribution status and its impact on agricultural crops, animals and human health in Africa. The review also highlights areas for research in managing this noxious weed in the African habitats.

Present status of aquaculture and the challenge of bacterial diseases in freshwater farmed fish in Tanzania;A call for sustainable strategies

Aquaculture provides significant contributions to household food security,as the capture of wild fish from lakes,dams,and oceans do not meet the current demand for animal protein in Tanzania.Sustainable aquaculture requires well-established regulatory systems and extension services for good pond management practices and maintaining fish health by fish farmers.Fish farming is practiced widely in Tanzania,from small-to large-scale ponds and these farming systems are moving from extensive normal operations(low input demand)to intensive farming(high input demand).However,the industry is largely still operating at a subsistence level with low production.Bacterial infections have been occurring in these fish farms and will continue to be an issue of concern into the future.This review highlights the current challenges,successes,and prospects towards a sustainable aquaculture industry in Tanzania,including:limited extension services mirroring the limited knowledge by farmers regarding pond management practices;the inadequacy of funds to carry out fish disease research or implement a surveillance system;little expertise in fish disease diagnosis and treatment;and poor management options.To minimize disease outbreaks and optimize production in the future,we suggest a strengthening of extension services,augmented with on-farm knowledge transfer.Emphasis should be on pond management practices and fish disease management;the creation of a well-functioning fish disease surveillance system;and strengthening collaborative research on aquaculture between the government research institutions and academia.Establishing small cooperative fish farmer groups within the Aquaculture Association of Tanzania(AAT)for easy access to information is also recommended.

Potential of Controlling Common Bean Insect Pests (Bean Stem Maggot (<i>Ophiomyia phaseoli</i>), Ootheca (<i>Ootheca bennigseni</i>) and Aphids (<i>Aphis fabae</i>)) Using Agronomic, Biological and Botanical Practices in Field

Common bean production in Africa suffers from different constrains. The main damage is caused by insect pest infestations in the field. The most common insects pests which attack common bean in the field are the bean stem maggot (Ophiomyia phaseoli), ootheca (Ootheca bennigseni) and aphids (Aphis fabae). Currently, few farmers in Africa are using commercial pesticides for the control of these insect pests. Due to the negative side effects of commercial pesticides to human health and the environment, there is a need for developing and recommending alternative methods such as those involving agronomic and botanical/biological measures in controlling common bean insect pests. This review aim to report the most common insects pests which attack common bean (Phaseolus vulgaris L.) in the field and explore the potential of agronomic, biological and botanical methods as a low-cost, safe and environmentally friendly means of controlling insect pests in legumes.