Dispersal of the sugar-cane scale Aulacaspis tegalensis (Zhnt.) (Hem., Diaspididae) by air currents

1972 ◽  
Vol 61 (3) ◽  
pp. 547-558 ◽  
Author(s):  
D. J. Greathead
Keyword(s):  
Sugar Cane ◽  
Laboratory Experiments ◽  
Sticky Trap ◽  
Research Station ◽  
High Humidity ◽  
Dispersal Mechanism ◽  
Large Numbers ◽  
Speed Up ◽  
Trap Catches ◽  
Aulacaspis Tegalensis

By means of sticky traps and a suction trap, it was demonstrated on a plot of sugar-cane at Kawanda Research Station, Uganda, that large numbers of crawlers of Aulacaspis tegalensis (Zhnt.) become airborne (up to 10/m3). The numbers increase with wind speed up to about 2·0 m/s and then remain constant, but are depressed by increasing humidity. In laboratory experiments, crawler survival was reduced by high temperatures (30°C) and low humidities (30% r.h.), but some individuals should survive the extreme conditions sometimes experienced if airborne from morning until evening. On hatching, crawlers move upwards and towards the light, but downwards in the dark; movement is inhibited by high humidity. These behaviour responses indicate hat the presence of crawlers in the air is not accidental but a dispersal mechanism. At Arusha Chini, an isolated sugar estate in Tanzania, sticky-trap catches downwind of a windbreak confirmed that airborne dispersal of crawlers is a major source of infestation. It is shown that air currents could have carried crawlers to Arusha Chini from a source on the Kenya coast, 260 km to the east.

Interactions between the land snails Theba pisana and Cernuella virgata in the laboratory

2020 ◽  
Author(s):  
Geoff H Baker
Keyword(s):  
Laboratory Experiments ◽  
Distribution Patterns ◽  
Land Snails ◽  
Snail Species ◽  
Agricultural Pests ◽  
Large Numbers ◽  
Small Scales ◽  
Novel Method ◽  
Theba Pisana ◽  
Inhibitory Components

ABSTRACT Two Mediterranean snails, Theba pisana and Cernuella virgata, are agricultural pests in southern Australia. The two species are rarely found together in large numbers in the field, at small scales (<1 m2). In laboratory experiments, the presence of T. pisana reduced the survival of C. virgata, but only when food (carrot + lettuce) was provided. When C. virgata was exposed to only the mucus trails and faeces of T. pisana, produced while feeding on lettuce, both the survival and activity of C. virgata were reduced. When carrot was substituted for lettuce, there was less effect. In addition, when C. virgata was exposed to T. pisana’s faeces only, derived from access to a mix of lettuce and carrot, there was no effect on C. virgata’s survival. The observed reductions in the survival of C. virgata were stronger in autumn (the breeding season for both snail species) compared with spring. Inhibitory components within the mucus trails of T. pisana may (1) help explain the observed distribution patterns of the two species at small scales in the field and (2) provide a novel method for control of pest populations of C. virgata, in some situations.

FPGA Realization of the Reconfigurable Mesh Counting Algorithm

2021 ◽  
pp. 2150157
Author(s):  
Yosi Ben-Asher ◽  
Esti Stein ◽  
Vladislav Tartakovsky
Keyword(s):  
Lower Bound ◽  
Neural Nets ◽  
Processing Elements ◽  
Large Numbers ◽  
Unrealistic Assumption ◽  
Reconfigurable Mesh ◽  
Speed Up ◽  
Optimal Tree ◽  
Pass Transistor ◽  
Signal Switching

Pass transistor logic (PTL) is a circuit design technique wherein transistors are used as switches. The reconfigurable mesh (RM) is a model that exploits the power of PTLs signal switching, by enabling flexible bus connections in a grid of processing elements containing switches. RM algorithms have theoretical results proving that [Formula: see text] can speed up computations significantly. However, the RM assumes that the latency of broadcasting a signal through [Formula: see text] switches (bus length) is 1. This is an unrealistic assumption preventing physical realizations of the RM. We propose the restricted-RM (RRM) wherein the bus lengths are restricted to [Formula: see text], [Formula: see text]. We show that counting the number of 1-bits in an input of [Formula: see text] bits can be done in [Formula: see text] steps for [Formula: see text] by an [Formula: see text] RRM. An almost matching lower bound is presented, using a technique which adds to the few existing lower-bound techniques in this area. Finally, the algorithm was directly coded over an FPGA, outperforming an optimal tree of adders. This work presents an alternative way of counting, which is fundamental for summing, beating regular Boolean circuits for large numbers, where summing a vast amount of numbers is the basis of any accelerator in embedded systems such as neural-nets and streaming. a

scholarly journals Experimental Study on the Insulation Layer Thickness of a Novel Ice Coring Device in Loose Sandstone-Type Uranium Deposits

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7448
Author(s):  
Chaoyang Huang ◽  
Jianming Peng ◽  
Yanliang Li ◽  
Moke Lian ◽  
Chao Guo ◽  
...  
Keyword(s):  
Laboratory Experiments ◽  
High Reliability ◽  
Freezing Process ◽  
The Novel ◽  
Uranium Deposits ◽  
Insulation Layer ◽  
Cold Source ◽  
Cold Energy ◽  
Speed Up ◽  
Drill Tool

The target strata of sandstone-type uranium deposits are usually located in the fragile and loose strata, which makes it difficult to obtain core samples; consequently, a novel ice coring device for loose sandstone-type uranium deposits is proposed to solve this problem. Experiments proved that the artificial sample can replace the natural sample, and the coring method has high reliability. Ensuring the allegro formation of an ice valve with a given cold source is critical for this coring system, and reducing the loss of cold energy with help of insulation layer is one of the methods to speed up the formation of ice valve. Since the diameter of the drill tool is limited by its working scenario, the thickness of insulation layer is limited to ensure the size of core. Therefore, this paper conducted laboratory experiments of the insulation layer with different thicknesses to study the effect of the insulation layer on the formation of the sand–ice valve. Results show that the insulation layer can reduce the loss of cold energy during the freezing process and significantly affect the formation time of the sand–ice valve. When the thickness of the aerogel insulation layer is 2 mm, the freezing time is 44% shorter than that without insulation layer. According to the tests, the novel ice coring device is expected to solve the coring problem in loose sandstone-type uranium deposits.

scholarly journals Population Dynamics of Released Potato Psyllids and their Bacteriliferous Status in Relation to Zebra Chip Incidence in Caged Field Plots

Plant Disease ◽  
2016 ◽  
Vol 100 (8) ◽  
pp. 1762-1767 ◽  
Author(s):  
F. Workneh ◽  
L. Paetzold ◽  
A. Rashed ◽  
C. M. Rush
Keyword(s):  
Disease Incidence ◽  
Sticky Trap ◽  
Research Station ◽  
Zebra Chip ◽  
Sticky Traps ◽  
Monitoring Tools ◽  
Candidatus Liberibacter ◽  
Yellow Sticky Trap ◽  
Successive Generations ◽  
Field Plots

Potato psyllids vector ‘Candidatus Liberibacter solanacearum’ (Lso), the putative causal agent of potato zebra chip (ZC). Currently, sticky traps are the primary psyllid monitoring tools used by growers for making management decisions. However, the reliability of sticky traps in predicting psyllid numbers in potato fields has always been questioned. In 2013 and 2014, experiments were conducted in covered field plots at the Texas A&M AgriLife Research Station at Bushland to investigate the relationships among initial psyllid numbers, psyllids captured on sticky traps and their Lso status, and zebra chip incidence. Three densities of Lso-positive psyllids (5, 15, or 30/cage) were released under 2-week-old potato canopies with four replications in plot sizes of 7.6 to 9 m by 5 rows. Psyllids were released under the first plant in the center row and monitored weekly with a yellow sticky trap from the opposite end. Number of plants with zebra chip symptoms also was counted weekly beginning one month after infestation with psyllids. The total number of psyllids captured on sticky traps and disease incidence levels generally corresponded to the levels of psyllid density treatments (5 < 15 < 30), but the differences became more apparent toward the end of the experiments. Psyllid numbers in the different density treatments fluctuated more or less in synchrony over time, which appeared to reflect periodic emergence of new generations of psyllids. Initially, all captured psyllids tested positive for Lso. However, the proportions of psyllids testing positive declined dramatically after a few weeks, which suggested that the new generations of psyllids were devoid of Lso. Over all, less than 50% of captured psyllids tested positive for the pathogen. The decline in proportions of psyllids testing positive for Lso following successive generations has significant relevance to field situations and may partly explain why there are generally low percentages of Lso-positive psyllids under field conditions.

scholarly journals Olfactory Preference of Drosophila suzukii Shifts between Fruit and Fermentation Cues over the Season: Effects of Physiological Status

Insects ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 200 ◽  
Author(s):  
Rik Clymans ◽  
Vincent Van Kerckvoorde ◽  
Eva Bangels ◽  
Wannes Akkermans ◽  
Ammar Alhmedi ◽  
...  
Keyword(s):  
Laboratory Experiments ◽  
Physiological Status ◽  
Drosophila Suzukii ◽  
Apple Cider ◽  
Baited Traps ◽  
Full Complement ◽  
Protein Rich ◽  
Trap Catches ◽  
Olfactory Behaviour ◽  
Preference Experiment

Worldwide monitoring programs of the invasive fruit pest Drosophila suzukii Matsumura (Diptera: Drosophilidae), using fermentation baits like apple cider vinegar (ACV), revealed a counterintuitive period of low trap catches during summer, followed by an autumn peak. In this study, we demonstrate that ACV baited traps indeed provide a distorted image of the D. suzukii population dynamics as it is possible to capture higher numbers during this “low capture period” with synthetic lures. It was hypothesised that the preference of D. suzukii populations for fermentation cues like ACV is most pronounced during autumn, winter and spring, while the flies prefer fresh fruit cues during summer and that this seasonal preference is related to the changing physiology of the flies over the season. To test this hypothesis, the preference between fermentation cues (ACV) and host fruits (strawberries) and the effect of physiology (sex, seasonal morphology and feeding, mating and reproductive status) was investigated both in olfactometer laboratory experiments and a year-round field preference experiment. In olfactometer experiments we demonstrated that protein deprived females, virgin females with a full complement of unfertilised eggs and males show a strong preference for fermentation cues while fully fed reproductive summer morph females generally prefer fruit cues. These findings indicate that D. suzukii is attracted to fermentation volatiles in search of (protein-rich) food and to fruit volatiles in search of oviposition substrates. Winter morph and starved females displayed indiscriminating olfactory behaviour. In the field preference experiment, the hypothesised seasonal shift between fermentation and fruit cues was confirmed. This shift appeared to be highly temperature-related and was similarly observed for summer and winter morphs.

Experimental transmission of Gyrodactylus salaris Malmberg, 1957 (Platyhelminthes, Monogenea) from the Atlantic salmon (Salmo salar) to the European eel (Anguilla anguilla)

1991 ◽  
Vol 69 (3) ◽  
pp. 733-737 ◽  
Author(s):  
T. A. Bakke ◽  
P. A. Jansen ◽  
L. P. Hansen
Keyword(s):  
Laboratory Experiments ◽  
Transmission Rate ◽  
Anguilla Anguilla ◽  
European Eel ◽  
Parasite Transmission ◽  
Experimental Transmission ◽  
Dispersal Mechanism ◽  
Maximum Duration ◽  
Parasite Survival ◽  
Duration Of Infection

Laboratory experiments were designed as follows in an attempt to evaluate the potential importance of eels in dispersal of Gyrodactylus salaris: exposure of uninfected eels to infected salmon; exposure of infected eels to uninfected salmon; exposure of uninfected eels to infected eels; indirect infection of uninfected eels; parasite transmission preference, using "two-choice" host tests; and parasite survival on eels following their isolation. Gyrodactylus salaris was found to be transmissible from salmon to eels, and vice versa, both at 4 and 13 °C. Eel to eel transfer of G. salaris was also demonstrated, as was infection of fish from the bottom of the tank. Transmission of G. salaris to eels also occurred in the "two-choice" host tests. Transmission rate was positively correlated with water temperature and transmission was more frequent from dead than living infected salmon. The maximum duration of infection on eels was 8 days. The transfer of infection to eels is thought to parallel events in nature and forms part of the dispersal mechanism of G. salaris.

College recruiting using social media: how to increase applicant reach and reduce recruiting costs

2015 ◽  
Vol 14 (4) ◽  
pp. 135-141 ◽  
Author(s):  
Shahid Wazed ◽  
Eddy S.W. Ng
Keyword(s):  
Social Media ◽  
College Graduates ◽  
Content Type ◽  
Call To Action ◽  
Large Numbers ◽  
Alternative Approach ◽  
The Social ◽  
Job Opportunity ◽  
Speed Up ◽  
Prospective Employer

Purpose – The purpose of this paper is to offer an alternative approach to traditional campus recruiting, using the social media. Specifically, we propose a three-step strategy using Facebook to attract and recruit college graduates. Design/methodology/approach – In Step 1, employers use Facebook to attract as many target students as possible to an employer’s Fan page. In Step 2, employers actively engage with students to enhance their employer brand as a prospective employer. In Step 3, employers initiate a call-to-action to encourage students to act upon a job opportunity and apply for the position. Findings – Social media recruiting can payoff in several ways: First, employers have the advantage of speed through social media recruiting. Second, employers also have broad and frequent access to college students. Employers will also reduce their overall college recruiting costs and lastly, employers enhance their overall employment branding through the use of Facebook for college recruiting. Practical implications – Given the impending retirement of baby boomers, there is an urgent need to recruit college graduates in large numbers. Historically, college recruiting has been the preferred channel; however, few students attend campus career fairs or find information sessions and their campus career centers helpful. As an alternative, employers should consider using social media as a recruiting tool to attract and recruit college graduates. Originality/value – Social media recruiting has the potential to help smaller employers stand out among larger employers, reach out to a larger pool of candidates, speed up the recruitment process and reduce overall recruitment costs.

An Experiment on the Control of Tsetse (Glossina palpalis R.-D.) in High Forest of West Africa

1953 ◽  
Vol 44 (4) ◽  
pp. 703-710 ◽  
Author(s):  
B. J. A. Nowosielski-Slepowron
Keyword(s):  
Relative Humidity ◽  
West Africa ◽  
Rain Forest ◽  
Forest Type ◽  
Complete Eradication ◽  
Large Numbers ◽  
High Reduction ◽  
Trap Catches ◽  
The Town ◽  
Glossina Palpalis

Kumasi is a rapidly expanding township of about 80,000 inhabitants. This has led to an extensive building programme which has followed the ridges in the vicinity of the town, leaving the valleys in between potentially dangerous isolated habitats of Glossina. The danger from these isolated habitats is enhanced by the large numbers of itinerant labourers.The topography of the town and its surroundings is hilly; the vegetation is of semi-deciduous rain forest type, but with very thick secondary bush along most of the valleys in which the farms had been abandoned.The climate is remarkably equable with the rainfall showing periodicity but the percentage relative humidity is high and even throughout the year.The experimental clearing of an isolated habitat of Glossina in the Dechem valley was commenced in July 1950 and finished in March 1951. The clearing was of a discriminative nature, with cutting, stumping and burning of a strip of bush up to 20 ft. high and 250–300 yards wide along the stream, and a high reduction of fly population was achieved. This reduction was such that further clearings were planned.The reduction in fly population was assessed from fly-boy catches and from trap catches. These records showed that rainfall affected the catches.At the time of writing, about a sixth of the protective clearings planned around Kumasi have been completed, the fly population being reduced between about 80 per cent. and complete eradication.

The analysis and standardisation of light-trap catches of Heliothis armiger (Hübner) and H. punctiger Wallengren (Lepidoptera: Noctuidae)

1981 ◽  
Vol 71 (2) ◽  
pp. 207-225 ◽  
Author(s):  
R. Morton ◽  
L. D. Tuart ◽  
K. G. Wardhaugh
Keyword(s):  
Wind Speed ◽  
Light Trap ◽  
Adult Emergence ◽  
Wind Speeds ◽  
South Wales ◽  
Large Numbers ◽  
Successive Generations ◽  
Hourly Distribution ◽  
A Site ◽  
Trap Catches

AbstractHourly and nightly catches of Heliothis armiger (Hb.) and H. punctiger Wllgr. at a site adjacent to 2000 ha of commercial cotton in the Namoi Valley of New South Wales, were analysed in relation to various environmental factors and showed that wind speed, temperature, night-length and (H. armiger only) moonlight exerted a significant influence on trap-catch. For H. punctiger and H. armiger respectively, these factors accounted for 80 and 60% of the deviance in hourly catches but only 70 and 40% of the variation in nightly catches. Wind speeds of more than 1·7 m/s suppressed the catch of both species but had a greater effect on H. punctiger than H. armiger. Whereas with both species, the optimum temperature for trapping was about 27°C, temperature had a greater influence on the catch of H. punctiger than of H. armiger. Bright moonlight was estimated to reduce the catch of H. armiger by 49%, but no significant effect was detected for H. punctiger. The analysis revealed a number of occasions for both species in which the hourly distribution of catch and/or the change in catch between successive nights was aberrant. With H. armiger, these inconsistencies appeared to be associated with changes in population due to adult emergence, whereas for H. punctiger the most likely cause seemed to be changes due to movement. The combined effects of wind speed, temperature, night-length and moonlight were used to adjust the nightly catches of each species according to the environmental conditions prevailing on a ‘ standard’ night. This was defined as a typical summer's night with temperatures decreasing from 28·8°C at dusk to 20·6°C at dawn and ideal catching conditions, i.e. no moon and wind speed never exceeding 1·7 m/s. As such, the adjusted catches could be taken as indices of moth abundance. These showed that H. armiger had three discrete periods of abundance, characterised by the presence of large numbers of young moths and spaced at intervals suggesting successive generations. A similar pattern was lacking in H. punctiger, which was abundant only during the first half of the season. Except during periods of emergence (H.armiger), or once when spraying occured during daylight, the aerial application of insecticides to the cotton adjecent to the light-trap resulted in marked reductions in the populations of both species.

scholarly journals Sugar Cane Cake and Mineral Fertilizers on Coconut (Cocos nucifera Linn.) Seedlings

CORD ◽  
2009 ◽  
Vol 25 (2) ◽  
pp. 11
Author(s):  
Luiz Gonzaga Bione Ferraz ◽  
Ademar Barros da Silva ◽  
José Nunes Filho ◽  
Antonio Raimundo de Sousa ◽  
Venézio Felipe dos Santos
Keyword(s):  
Sugar Cane ◽  
Chemical Elements ◽  
Cocos Nucifera ◽  
Block Design ◽  
Organic Fertilizer ◽  
Mineral Fertilizers ◽  
Research Station ◽  
Linear Quadratic ◽  
Two Factors ◽  
And Control

High quantities of mineral fertilizers (MF) are required for good coconut seedling production, whose up dated recommendation is 232 grams per seedling. The objective of this work was to assess the substitution of the MF by organic fertilizer as sugar-cane filter cake (SCFC) on coconut seedlings in polybag. The SCFC is an organic residue from sugar-cane manufacturing composed of various chemical elements, as for instance: nitrogen, phosphorus, potassium, calcium and magnesium. The experiment was carried out at the Itapirema Research Station, Goiana, Pernambuco State, Brazil, in a randomized complete block design, with factorial disposition 52, replicated three times, with six tall coconut seedlings per plot. The treatments were the combinations of five doses of MF (in g seedling-1): 46.25; 92.50; 138.75; 185.00 and control, using urea, simple superphosphate and potassium chloride at the proportion of 1:2:3, respectively, and five doses of SCFC (in kg polybag-1): 0.5; 1.0; 1.5; 2.0 and control. Eight months after young coconut seedlings replacement to the polybags the following parameters were measured: collar girth (CG), leaf area (LA), number of live leaves (NL) and plant height (PH). For leaf nutritional diagnosis and growing media chemical and physical analyses, samples were collected. There was significance for the two factors, individually, to all parameters. The trend analysis revealed linear, quadratic and cubic responses, according to the studied character. The mixture of 0.5 kg of SCFC polybag-1 plus 46.25 g of the MF was sufficient for obtaining seedlings of excellent quality and promoting a fertilizers economy around 80%. According to other results from this research, the number of seedlings per plot and the critical level of nutrients in the leaf of coconut seedlings should be reviewed.

Sign in / Sign up

Export Citation Format

Share Document