2,148 research outputs found
Wild record of an apple snail in the Waikato River, Hamilton, New Zealand and their incidence in freshwater aquaria
No full textWe report the discovery of a single specimen of a live apple snail Pomacea diffusa Blume 1957 (Ampullariidae: Prosobranchia), from the Waikato River, Hamilton city, central North Island, New Zealand. This species, along with the congeneric P. insularum, is imported for the aquarium trade, and its occurrence in the river likely stemmed from an aquarium release. A survey of 55 aquaria belonging to 43 hobbyists revealed 27 apple snails, with one owner having 22 snails. Assessment of environmental tolerances and impacts of P. diffusa, based largely on studies of the closely related and commonly confused congener P. bridgesii, suggests that direct habitat impacts by this species are likely to be minor. However, there could be indirect influences on native biodiversity through predation on eggs or competition for food supplies with other detritivorous species if densities were to become high. Water temperatures in the Waikato River below Hamilton (10-23˚C in 2009) may enable released individuals to persist for an extended period, and over summer may exceed the threshold required to enable breeding. However, population establishment would be most likely in locations where water is heated through geothermal influences or industrial cooling water discharges
Turbulent drag reduction by hydrophobic surfaces with shear-dependent slip length
No full textThe stabilisation of a parabolic equilibrium profile in a three-dimensional (3D) turbulent channel flow for an incompressible fluid is addressed with the objective of achieving drag reduction. The formulation of this problem stems from Balogh’s work [1] where Lyapunov stability analysis was used to devise prototype feedback laws and prove global stability of the solutions. This treatment only considers the controller as a mathematical artefact, but it can actually be linked to physical control strategies modelling hydrophobic surfaces and porous media. In the former, only linear slip velocity boundary conditions (BC) were considered [8]. However, experiments [2] have suggested that the slip length may be shear-dependent. Motivated by these, the effect on drag reduction of a shear-dependent slip length surface is examined in the present study using Direct Numerical Simulations (DNS) at Re τ0 = u τ0 δ/ν ≃ 180. δ is the channel half height, u τ0 the wall-shear velocity for regular no-slip walls channel and ν the kinematic viscosity. The theoretical analysis in [5], is extended to this new model. The proposed formulation shows that the skin-friction coefficient can be reduced by tuning the parameters in the shear-dependent slip length model. The results, which verified by DNS simulations, show that by taking a slip length value based on a constant slip model [8] and combining it within a shear-dependent model, up to 50% drag reduction can be obtained. The effect of control is further assessed by formulating the Fukagata identity [4] with general boundaries; the weighted Reynolds shear-stress for each quadrant shows an enhanced reduction in the sweep/ejection events compared to the constant slip model
Study and Development of Instrument for Plant Protection Applications Associated with Apple and Picrorhiza kurroa (Kutki) Diseases
No full textIn the present research paper, plant response to the environment and disease monitoring system is presented, which is based on the meteorological approach and digital information and communication technology (ICT). It predicts the growth of kutki or apple fruit diseases such as Apple scab, Marssonina blotch, Red mite pest, etc. This system provides solutions to the farmers to mitigate the disease risk. Growth of apple disease and pests are highly dependent on various environmental parameters such as temperature, relative humidity (RH), leaf wetness, etc., which are measured by developing sensor arrangements and using a prediction model by which the index of infection is calculated. It tells about the severity of risk in crop management. This information can be sent to the farmer's mobile phone and also to the server located at far away from the field using GSM-GPRS (General packet radio service) so that they can easily handle the risk of pest control management. This ICT application consists of both hardware and software tools developed by the author
Hydrodynamical turbulence by fractal fourier decimation
No full textWe present a systematic numerical investigation of high-resolution 3D isotropic and homogeneous turbulence resolved on a decimated set of Fourier modes. Fractal decimation acts to decrease the effective dimensionality of the flow by allowing triadic interactions only in a set of Fourier modes N(k) proportional to k^DF for large k. While keeping the symmetries of the original 3D Navier-Stokes equations unchanged, a dramatic change in small-scale statistics is detected at decreasing the fractal dimension DF . Already at fractal dimension DF = 2.8, a global self-similar behaviour is observed in the inertial range of scales, the consequence of such transition are the restoration of the scaling symmetry and vorticity distribution that becomes close to Gaussian. We relate the results to the different roles of local vs non-local interactions in the energy transfer range
LABORATORY TESTS OF BIOLOGICAL PREPARATIONS AGAINST LEPIDOPTHERA PESTS OF APPLE ORCHARDS IN THE SOUTH-EAST OF KAZAKHSTAN
No full textThe paper provides information on laboratory testing of several biological preparations against caterpillars of lepidoptera pests of apple orchards – clouded drab Orthosia incerta (Hufnagel, 1766), apple ermine Yponomeuta malinellus Zeller, 1838, rose tortrix Archips rosana (Linnaeus, 1758) and brown oak tortrix Archips crataegana (Hübner, 1799). The most effective, according to the results of the tests, were the biological preparations Fitoverm® k.e., Entolek Planteko K®, Green Gold 0.3% wt.e. and Lepidocid® s.k. At the same time, the effectiveness of each drug varied depending on the species of the harmful object. This should be taken into account when selecting biological garden protection products
The Impact of Agricultural Products Insurance on Using Technical-Healthy Regulations of Production: A Case Study of Industrial Livestock and Apple Farms
No full textAgricultural insurance is considered as a support policy that reduces negative effects of risk in agricultural farms. In addition, it can improve managerial behavior of insured and technical-healthy regulations of production by using some special tools. This study investigated the impact ofinsurance of agricultural products insurance on using technical-healthy regulations of production in industrial livestock farms at Khorasan province and apple farms at Damavand County. To this end, the required data were survyed from the farms; then it was statistically analyzed. Results indicated that the insurance has exactly significant influence on using any of technical-healthy regulations of production in industrial livestock farms; whereas the insurance does not have any significant influence in the apple farms. In addition, it was also found out that the greatest influence of insurance was in industrial livestock and apple farms that had less than 200 animals and 3 hectares farms, respectively
Caracterização molecular e morfofisiológica da incompatibilidade alélica entre cultivares de macieira
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Agrárias. Programa de Pós-Graduação em Recursos Genéticos Vegetais
Least Squares Fitting of Chacón-Gielis Curves by the Particle Swarm Method of Optimization
No full textRicardo Chacón generalized Johan Gielis's superformula by introducing elliptic functions in place of trigonometric functions. In this paper an attempt has been made to fit the Chacón-Gielis curves (modified by various functions) to simulated data by the least squares principle. Estimation has been done by the Particle Swarm (PS) methods of global optimization. The Repulsive Particle Swarm optimization algorithm has been used. It has been found that although the curve-fitting exercise may be satisfactory, a lack of uniqueness of Chacón-Gielis parameters to data (from which they are estimated) poses an insurmountable difficulty to interpretation of findings.Least squares multimodal nonlinear curve-fitting; Ricardo Chacón; Jacobian Elliptic functions; Weierstrass ; Gielis super-formula; supershapes; Particle Swarm method; Repulsive Particle Swarm method of Global optimization; nonlinear programming; multiple sub-optima; global; local optima; fit; empirical; estimation; cellular automata; fractals
Valuations of ‘Sustainably Produced’ Labels on Beef, Tomato, and Apple Products
No full textThis study evaluates consumer perceptions of what “sustainably produced†food labels imply and estimates corresponding demand for products carrying these labels. Results suggest that the typical U.S. consumer is not willing to pay a positive premium for beef, tomatoes, or apple products labeled as “sustainably produced.†Demand is particularly sensitive to inferences consumers make regarding what a “sustainably produced†food label implies. Suggestions for future work and implications of standardizing the definition of sustainability are provided.consumer perceptions, credence labeling, production practices, sustainable, U.S. consumer demand, willingness to pay, Marketing,
Disease Forecasting and Pest Management for Indian Apple: An Application of ICT
No full textApple is one of the most widely cultivated fruit crops in region of northern hilly area of Jammu & Kashmir and Himachal Pradesh. In the present study a system is suggested and under development by authors using the information and communication technology (ICT) which predict the growth of various disease in Apple fruit like Apple scab, Marssonina blotch, Red mite pest etc. and communicate to farmers on their mobile about pre information of severity of disease so that they can easily handle the risk by pest management. This system provides solution to mitigate the disease risk. As an ICT tools different kind of wireless sensors, Data acquisition Card, computer, network protocol (TCP/IP), GPRS, GSM mobile communication module and web interface protocol were used to design the complete forecasting system. Growth of apple disease and pests are highly dependent on various environmental parameters like temperature, Relative humidity (RH), wind velocity/direction, and leaf wetness duration that were measured by particular sensors and using prediction model the infection of index was calculated which tells about severity of risk and this information are sent to farmers and also to the server located at far away from field using GPRS (General packet radio service). This ICT application consist both hardware and software phase to extract the information about the risk and this processed information is shared on web page which can be easily accessible from every corner of the world
- …
