Proceedings

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EISSN : 25043900
Current Publisher: MDPI (10.3390)
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Latest articles in this journal

Mukund Madhav, Geoff Brown, Jess A. T. Morgan, Sassan Asgari, Elizabeth McGraw, Peter James
Published: 21 January 2020
by MDPI
Proceedings, Volume 36; doi:10.3390/proceedings2019036079

Abstract:Buffalo flies, Haematobia (irritans) exigua (BF), are obligate haematophagous ectoparasites of cattle that cause significant economic and welfare impacts in northern Australian cattle. With climate change and the development of resistance to commonly used chemicals, BF are rapidly spreading southwards. Wolbachia is a maternally transmitted bacterial endosymbiont of insects that induces a range of effects on its host, including cytoplasmic incompatibility (male sterility), reduced fitness, and inhibition of pathogen transmission. We are examining the potential for use of Wolbachia in area-wide control of BF. Following a survey of Australian BF populations that showed Wolbachia was not present, we have tested embryonic microinjection, pupal injection and injection of adults as a first step towards the development of a Wolbachia infected BF line. Here we report distribution and growth of Wolbachia in somatic and germline tissue of BF injected with the three Wolbachia strains; wAlbB, wMel and wMelPop. Our results to date suggest that pupal or adult injection may be a more suitable method for transinfecting BF than embryonic microinjection. We also demonstrate Wolbachia induced fitness effects in injected BF including shortened lifespan, decreased pupal emergence, and reduced egg production. Future work will focus on establishing a stably infected BF strain, towards the design of Wolbachia-based control programs for BF.
Khurram Ziaf, Muhammad Wasim Haider, Aman Ullah Malik, Raheel Anwar, Rehan Riaz
Published: 21 January 2020
by MDPI
Proceedings, Volume 36; doi:10.3390/proceedings2019036084

Abstract:Onion (Allium cepa L.), locally famous as “Piaz”, occupies a prominent place among commercial crops of Pakistan, by supplementing the income of small/marginal land-hold farmers. One of the major constraints of onion farming in Pakistan is poor nursery due to adoption of traditional planting methods and overfertilization, which ultimately increases cost of production and loss of resources. The current study, comprised of two experiments, was carried out at Vegetable Area, University of Agriculture Faisalabad, to determine the most suitable nursery raising system and fertilizer application rate for onion nursery in order to get maximum plant population of good quality seedlings. The first experiment comprised of four different nursery growing methods: (1) flat bed + broadcast sowing, (2) flat bed + line sowing, (3) raised bed (6 inches height from ground surface) + broadcast sowing, and (4) raised bed + line sowing. The largest plant population, and highest plant fresh and dry weights were obtained on flat beds under line sowing. The smallest plant population was obtained on raised beds under broadcast sowing, however, the lowest fresh and dry weights of seedlings were found with flat beds under broadcast sowing. The second experiment comprised of three diammonium phosphate (DAP) application rates (50 g, 100 g and 150 g per 272.25 ft−2 applied at one-week interval) and a control. The maximum shoot and root lengths as well as fresh and dry weights were obtained with 100 g DAP 272 ft−2. In conclusion, line sowing on flat beds and application of 100g DAP 272 ft−2 at one-week interval produced high quality nursery of onion cv. Phulkara. But, flat bed system must be coupled with proper drainage to avoid excessive water due to frequent rainfall in tropical areas.
WiroJ Homsup, Jeadsada Pinyochon, Pitikorn Narathee, Supita Weng, Nuttaka Homsup
Published: 21 January 2020
by MDPI
Proceedings, Volume 39; doi:10.3390/proceedings2019039026

Abstract:This paper presents a dynamic simulation of Unmanned Aerial Vehicle (UAV) moving on a launcher. The UAV launcher consists of a metal rail that is positioned at a launch angle, a spring and a winch to be able to stretch the spring. Prior to launch the spring is stretched into necessary tension and secured with safety pins, then released to launch the UAV. The influence of aerodynamic lift and drag forces on the mathematical model of a UAV will be considered in detail. Mathematical model a UAV moving on a launcher represented by differential equations are solved using a MATLAB software. The results of calculations are represented by a graph which shows distance, velocity and acceleration of a UAV while moving on a launcher as a function of time.
Maiyer Xiong, Gomathy Palaniappan, Laurie Bonney
Published: 21 January 2020
by MDPI
Proceedings, Volume 36; doi:10.3390/proceedings2019036078

Abstract:A case study on Good Agricultural Practices (GAP) of vegetable was conducted in 2018, with an objective to understand whether GAP practices improve market access for vegetable farmers in the Lao PDR. The case study was conducted in Nasala Village, Xaythany District, Vientiane capital, Lao PDR. The data was collected using 10 semi-structured interviews and one group discussion with Nasala farmers. The results were summarized based on the themes such as community characteristics, market access and farmers’ perception about GAP. The Nasala community has 585 households, majority being farmers with 50% of them growing vegetables with an average farm size of 1.5 hectare. District Agriculture and Forestry Office (DAFO) introduced GAP practices as a pilot project to 28 farmers in Nasala in 2014 through farmer trainings. The DAFO pilot project enabled Nasala farmers to export Thorny Coriander to Japan during 2016–2017. Nasala farmers sold 50 kg/day of Thorny Coriander for about one year at the price of 15,000 kip/kg in comparison to 7000–10,000 kip/kg at the local market. Farmers agreed that they were motivated by the market incentives and collectively sold the produce by alternating production for continuous supply. This export opportunity was withdrawn after the pilot period resulting in no incentives to practice GAP. Farmers agreed that GAP enabled them to produce better quality, healthier and safer vegetables. However, the barriers to GAP are lack of government policies, institutional support, inadequate incentives and complex certification process. To enable farmers to continue GAP practices appropriate supporting system must be developed.
Gayathri Rajagopal, John Duff, Zara Hall
Published: 21 January 2020
by MDPI
Proceedings, Volume 36; doi:10.3390/proceedings2019036077

Abstract:Biofumigation involves growing specialised cover crops that have the ability to suppress certain soil-borne diseases. Species such as those in the Brassicaceae family, (e.g., radish, mustard and rocket) are known to have this capability. Biofumigation activity is initiated by the degradation of glucosinolates within the tissues of the plant when the crop is incorporated into the soil at approx. 25% flowering rate. In this experiment, nine bio-fumigant varieties were assessed over six planting dates for biomass yield, irrigation management, glucosinolate concentration and efficacy against three soilborne pathogens, namely; Sclerotium rolfsii, Sclerotinia sclerotiorum and Macrophomina phaseolina. Preliminary results showed incorporation dates varied across varieties and planting times. Winter planting had highest biomass yield across all varieties, compared with the summer plantings (e.g., 14.82 t/ha in winter, versus 5.02 t/ha in summer for Caliente). The efficacy of disease suppression was variable between variety and planting date. For example, Nemfix and BQ Mulch produced a higher percentage mortality rate (100% and 98%) against S. sclerotiorum, compared with autumn (22% and 12%) and winter (37% and 13%) planting. High glucosinolate production was observed during the summer plantings, where irrigation treatments including drought conditions (Low; 0.75 ML/ha), moderate watering (Medium; 2 ML/ha) and field capacity (High; 2.5 ML/ha) were applied. Increased glucosinolate concentrations were observed in the Low irrigation treatments (e.g., Mustclean; 32.31 μmol/g DW), versus High irrigation (e.g., Mustclean; 17.11 μmol/g DW). Summer data pending analysis. These findings can help growers to identify biofumigant varieties that compliment rotation program and optimise disease management practices.
Panupong Choochart, Chinnapat Thipyopas
Published: 21 January 2020
by MDPI
Proceedings, Volume 39; doi:10.3390/proceedings2019039025

Abstract:This study is a simulation of the evacuation of the passengers from the Airbus A330-300 aircraft and the objective is the efficient evaluation of passenger evacuation and to find the most efficient evacuation format. The Pathfinder simulation program is used for this study. The study is divide into two parts. The first scenario of the evacuation from the aircraft is using all exit doors simulated in 4 formats of evacuation tests as follows: Format (1) evacuate freely. Format (2) evacuate divided by area. Format (3) evacuate which passengers are determined to evacuate to the nearest exit door. Format (4) evacuate which the number of passengers evacuating via each exit door is equal. The result of the simulations indicated that the evacuation times were 50.9, 79.4, 50.6, and 58.6 s, respectively. The most efficient evacuation was format 3 and insignificantly different from format 1. The second scenario is the evacuation which 1 left-side exit door is unavailable and is simulated in format 1–4 as same as the first scenario. The shortest time of the evacuation with exit door 1L, 2L, 3L, and 4L unavailable were 51.3, 58.5, 62.6 and 59.3 s, respectively. The most efficient format for the evacuation with exit door 1L unavailable was format 1 and 3 while format 1 was the best for the evacuation with any left-side exit door unavailable. Accumulation and density of passengers in the cabin were analyzed and evacuation formats were adjusted by seat row for finding the shortest evacuation period. The adjusted format was simulated again and the evacuation times with door 1L or door 4L unavailable can be slightly decreased and the times were 49.3 and 59.0 s. The simulation of these two scenarios found that the best way to use for the aircraft evacuation is to evacuate freely.
Shammy Sarwar, Ram Mereddy, Michael E. Netzel, Gabriele Netzel, Yasmina Sultanbawa
Published: 21 January 2020
by MDPI
Proceedings, Volume 36; doi:10.3390/proceedings2019036080

Abstract:Strawberries, depending on the cultivar and environmental conditions, can be a rich source of nutrients like folates and vitamin C as well as bioactive phytochemicals, mainly polyphenols. But at room temperature, this fruit is highly perishable and has a relative short shelf life of only a couple of days. An innovative, cost effective and environmentally friendly technique, photosensitization, has been applied with the aim to extend the shelf life of strawberries and to minimize the loss of nutrients and also phytochemicals. Photosensitization works based on the combined action of photosensitizer, light and oxygen, which produce reactive oxygen species that inactivate microorganisms. Curcumin, known for its antifungal activity was used as the photosensitizer in this study. To see the effect of photosensitization, physicochemical parameters of both fresh and photosensitized strawberries have been tested. There were no significant (p < 0.05) changes in pH, titratable acidity, total soluble solids and moisture content between treated and untreated (control) strawberries. However, total sugar content of photosensitized strawberry was significantly (p < 0.05) higher than that of the control (5.29 ± 0.26 g/100 g FW vs. 4.12 ± 0.13 g/100 g FW). No significant difference was observed in the total phenolic content of the treated (192.9 ± 3.16 mg gallic acid equivalents (GAE)/100 g FW) and the control (195.8 ± 3.05 mg GAE/100 g FW) samples. These preliminary findings show that photosensitization could be a promising technique that has the potential to be used in the horticulture industry to extend the shelf life of fresh produce such as strawberries.
Wiebke Kämper, Helen M. Wallace, Steven M. Ogbourne, Stephen J. Trueman
Published: 21 January 2020
by MDPI
Proceedings, Volume 36; doi:10.3390/proceedings2019036076

Abstract:Cross-pollination is essential for the reproduction of self-incompatible plants and it improves the yield and fruit quality of some self-compatible plants. Cross-pollination of clonal horticultural crops is achieved only when pollen from one cultivar reaches the stigma of another cultivar. We quantified self- and cross-fertilisation rates in macadamia nuts (Macadamia integrifolia, M. tetraphylla and hybrids) that were harvested at different distances from a cross-pollen source in two different plantation designs (mixed blocks of multiple cultivars vs. pure blocks of a single cultivar). We also estimated the distance of effective pollen movement, evaluated how different pollen parents affect nut quality, and assessed whether distance from a cross-pollen source affected the number of nuts harvested. We found that almost all nuts resulted from cross-pollination in both plantation designs, with almost all nuts being cross-pollinated even at 23 rows from another cultivar. However, most pollen did not travel far, and nearby cultivars were usually the pollen parent. Cross-pollination increased nut mass and changed the nutritional quality of the nut. The number of nuts harvested decreased with increasing distance from a cross-pollen source in large pure blocks, but not in mixed blocks. Dependence on cross-pollination coupled with low distances of pollen movement may cause suboptimal fruit set. Our results suggest that fruit set in macadamia plantations comprised of large single-cultivar blocks is limited and that plantations can benefit from closer interplanting of different cultivars
Saleha Akter, Hung T. Hong, Michael E. Netzel, Ujang Tinggi, Simone Osborne, Mary Fletcher, Yasmina Sultanbawa
Published: 21 January 2020
by MDPI
Proceedings, Volume 36; doi:10.3390/proceedings2019036081

Abstract:Extracts were prepared from Terminalia ferdinandiana (Kakadu plum) fruits, leaves, seedcoats, and barks using accelerated solvent extraction with methanol, ethanol, water, acetone, and hexane. Antioxidant activity was assessed using the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay and by determining the total phenolic content (TPC). Methanol fruit extracts had the strongest free radical scavenging activity and the highest TPC (12 g/100 g DW). The antimicrobial activity of all extracts (except hexane) was analysed by agar disc diffusion. Fruits and leaves showed larger inhibition zones against foodborne bacteria Listeria monocytogenes, Bacillus cereus, methicillin resistant Staphylococcus aureus, and clinical isolates of Pseudomonas aeruginosa compared to seedcoats and barks. The minimum inhibitory and minimum bactericidal concentration of the extracts ranged from 1.0 to 3.0 mg/mL against the tested microorganisms. Scanning electron microscopy images of bacteria treated with the extracts showed morphological changes consistent with cell death. A new UHPLC-MS/MS method for the determination of punicalagin and castalagin, bioactive ellagitannins, was developed and validated. Punicalagin contents in the fruits and leaves were 74 and 49 mg/100 g DW whilst castalagin contents were 1.1 and 0.8 mg/100 g DW. To the best of our knowledge, this is the first report about punicalagin and castalagin concentrations in Kakadu plum fruits and leaves. These initial findings are very promising in regards to the potential use of Kakadu plum fruit and leaf extracts as natural preservatives in the food industry.
Keyu Tao, Wenwen Yu, Prakash Sangeeta, Robert Goulston Gilbert
Published: 21 January 2020
by MDPI
Proceedings, Volume 36; doi:10.3390/proceedings2019036082

Abstract:Cooked high-amylose rices have slower digestibility, giving nutritional benefits, but inferior eating qualities. In this study, Rapid Viscosity Analysis, quantitive descriptive sensory analysis with all panellists from China and Textural Profile Analyser (TPA) have been used to measure rice texture and eating quality of cooked rice. Molecular structural mechanisms for this inferior eating quality are found here using structural analysis by size-exclusion chromatography of both the parent starch and starch leached during cooking. All commonly-accepted sensory attributes of cooked rice were characterized by a trained human panel. Hardness, with the strongest negative correlation with panelist preference, is the dominant but not sole factor determining palatability. Rice with larger amylopectin size can bond more water, thereby have lower hardness value. Meanwhile, hardness is controlled by the amounts of medium and long amylopectin chains and amylose in the starch, and by amylose content and amount of longer amylopectin chains in the leachate. With this, it is concluded for the first time that rice containing 19~ 25% amylose content are most preferred by the panel. Meantime, it is showed that breakdown viscosity and swelling power of native rice flour can be and should be used as indicators for predicting rice eating quality. This gives knowledge and understanding of the molecular structural characteristics of starch controlling cooked-rice preference: not just high amylose but also other aspects of molecular structure. This can help rice breeders to target starch-synthesis genes to select slowly digested (healthier) rices with acceptable palatability.