1,589 research outputs found
Deep Tree Transductions - A Short Survey
The paper surveys recent extensions of the Long-Short Term Memory networks to
handle tree structures from the perspective of learning non-trivial forms of
isomorph structured transductions. It provides a discussion of modern TreeLSTM
models, showing the effect of the bias induced by the direction of tree
processing. An empirical analysis is performed on real-world benchmarks,
highlighting how there is no single model adequate to effectively approach all
transduction problems.Comment: To appear in the Proceedings of the 2019 INNS Big Data and Deep
Learning (INNSBDDL 2019). arXiv admin note: text overlap with
arXiv:1809.0909
Flaming, glyphosate, hot foam and nonanoic acid for weed control: a comparison.
Synthetic herbicides are commonly used in weed management, however, 70 years of
use has led to weed resistance and environmental concerns. These problems have led scientists to
consider alternative methods of weed management in order to reduce the inputs and impacts of
synthetic herbicides. The aim of this experiment was to test the level of weed control using four
weeding methods: glyphosate applied at an ultra-low volume, the organic herbicide nonanoic acid,
flaming, and hot foam. The results showed that weed control was eective only when flaming
and hot foam were applied (99% and 100% weed control, respectively). Nonanoic acid at a dose
of 11 kg a.i. ha1 diluted in 400 L of water did not control developed plants of Cyperus esculentus
(L.), Convolvulus arvensis (L.) and Poa annua (L.). Glyphosate at a dose of 1080 g a.i. ha1 (pure
product) only controlled P. annua (L.), but had no eect on C. esculentus (L.) and C. arvensis (L.).
After the aboveground tissues of weeds had died, regrowth began earlier after flaming compared
to hot foam. There was no regrowth of P. annua (L.) only after using hot foam and glyphosate.
Hot foam was generally better at damaging the meristems of the weeds. In one of the two experiment
sites, significantly more time was needed after the hot foam to recover 10% and 50% of the ground
compared to flaming. The time needed to recover 90% of the ground was on average 26–27 days
for flaming and hot foam, which is the time that is assumed to be required before repeating the
application. A total of 29 days after the treatments, weeds were smaller after flaming, glyphosate and
hot foam compared to nonanoic acid and the control, where they had more time to grow
Hot foam and hot water for weed control: a comparison
Thermal weed control plays an important role in managing weeds in synthetic herbicide-free systems, particularly in organic agriculture and in urban areas where synthetic herbicides are prohibited. This study compares the impact on weed control of increased doses of hot water and hot foam (i.e. 0, 0.67, 1.67, 3.33, 5.00, 6.67 and 8.33 kg m–2). The doses were applied using the same machine. The temperatures, weed control effectiveness, weed regrowth after the death of the aboveground vegetative weed tissues, and weed dry biomass 30 days after the treatments were studied in two experimental fields with a different weed composition (i.e. Site I and Site II). The results showed that difficult weeds
to control, such as Cynodon dactylon (L.) Pers., Digitaria sanguinalis (L.) Scop. and Taraxacum officinale Weber, like all the other species in the initial weed populations in the two experiments, died after lower doses of hot foam compared to hot water. Adding foam to hot water made it possible to lower the required dose of water by at least 2.5-fold compared to hot water used alone. By insulating the weeds, the foam led to higher peak temperatures and slower temperature decay, thus determining an effective weed control with lower doses compared to hot water. Starting from 11 days and 16 days after treatments (for Site I and Site II, respectively), there were no statistically significant differences in weed regrowth between hot foam and hot water at all the doses applied. There were no differences between the dry biomass of weeds collected 30 days after treatments when the same doses of hot foam and hot water were used
The influence of non-living mulch, mechanical and thermal treatments on weed population and yield of rainfed fresh-market tomato (Solanum lycopersicum L.)
Weed control is often a major limitation for vegetable crops, since compared to arable crops fewer herbicides are available and the crops are more sensitive to weeds. Field experiments were carried out in the province of Pisa (Central Italy) to determine the effect of two different mulches (black biodegradable plastic film and wheat straw) and mechanical and thermal treatments on weed population and yield of rain-fed fresh market tomato (Solanum lycopersicum L.). Rolling harrow, flaming machine and precision hoe for weed control, which were either built, enhanced or modified by the University of Pisa were used separately (mechanical-thermal strategy) or in combination with a straw mulch (mechanical-thermal-straw strategy). These two innovative strategies were compared with the traditional farming system, which uses a biodegradable plastic mulch film. The strategies were compared in terms of machine performance, weed density, total labour requirement, weed dry biomass, and crop fresh yield at harvest. The total operative time for weed control was on average ~25 h ha-1 for the two systems, which included mulching, and over 30 h ha-1 for the mechanical-thermal strategy. The three strategies controlled weeds effectively, with only 30 g m-2 in each treatment. Tomato yield, however, was 35% higher for strategies that included mulching (both biodegradable film and straw)
The use of different hot foam doses for weed control
Thermal weed control technology plays an important role in managing weeds in synthetic
herbicide-free systems, particularly in organic agriculture. The use of hot foam represents an evolution
of the hot water weed control thermal method, modified by the addition of biodegradable foaming
agents. The aim of this study was to test the weeding eect of dierent five hot foam doses, in two sites
of dierent weed composition fields [i.e., Festuca arundinacea (Schreb.), Taraxacum ocinale (Weber)
and Plantago lanceolata (L.)], by evaluating the devitalisation of weeds, their regrowth, the weed dry
biomass at the end of the experiment and the temperature of hot foam as aected by dierent foam
doses. The results showed that the eect of the hot foam doses diered with the dierent infested
weed species experiments. In the Festuca arundinacea (Schreb.) infested field, all doses from 3.33 L
m2 to 8.33 L m2 led to a 100% weed cover devitalisation and a lower weed dry biomass compared
to the dose of 1.67 L m2, whereas the weed regrowth was similar when all doses were applied. In the
Taraxacum ocinale (Weber) and Plantago lanceolata (L.) infested fields, doses from 5.00 L m2 to 8.33 L
m2 in site I and from 3.33 L m2 to 8.33 L m2 in site II led to 100% of weed cover devitalisation.
The highest doses of 6.67 L m2 and 8.33 L m2 led to a slower weed regrowth and a lower weed
dry biomass compared to the other doses. The time needed for weeds to again cover 50%, after
the 100% devitalisation, was, on average, one month when all doses were applied in the Festuca
arundinacea (Schreb.) infested field, whereas in the Taraxacum ocinale (Weber) and Plantago lanceolata
(L.) fields, this delay was estimated only when doses of 6.67 L m2 and 8.33 L m2 were used in site I
and a dose of 8.33 L m2 in site II. Thus, in the Festuca arundinacea (Schreb.) field experiments hot
foam doses from 3.33 L m2 to 8.33 L m2 were eective in controlling weeds, and the use of the
lowest dose (i.e., 3.33 L m2) is recommended. However, for Taraxacum ocinale (Weber) and Plantago
lanceolata (L.) the highest doses are recommended (i.e., 6.67 L m2 and 8.33 L m2), as these led to
100% weed devitalisation, slower regrowth, and lower weed dry biomass than other doses. A delay
in the regrowth of weeds by 30 days can lead to the hypothesis that the future application of hot foam
as a desiccant in no-till field bands, before the transplant of high-income vegetable crops, will provide
a competitive advantage against weeds
Using flaming as an alternative method to vine suckering.
Suckering is the process of removing the suckers that grapevine trunks put out in the
spring. Suckering by hand is costly and time consuming and requires constant bending down, getting
up and making repetitive motions. The mechanical removal of suckers with rotating scourges can
damage the vine plants. Chemical suckering is a limiting factor for wine grape growers interested in
sustainable and/or organic agriculture. The aim of this research was to test flaming as an alternative
method to vine suckering. A three-year experiment was conducted on a 10-year-old Sangiovese
vine (775 Paulsen rootstock). The treatments consisted of flame suckering at different phenological
stages, hand-suckering and a no-suckered control. Data on the number of suckers, grape yield
components, and grape composition were collected and analysed. The results showed that flaming
significantly reduced the initial number of suckers. This effect on the suckers was highest when
the main productive shoots of the vines were at the 18-19 BBCH growth stage. Flame-suckering
did not affect grape yield components and grape composition. Future studies could investigate the
simultaneous use of flaming for both suckering and weed control
experimental study of hydrogen embrittlement in maraging steels
Abstract This research activity aims at investigating the hydrogen embrittlement of Maraging steels in connection to real sudden failures of some of the suspension blades of the Virgo Project experimental apparatus. Some of them failed after 15 years of service in working conditions. Typically, in the Virgo detector, blades are loaded up to 50-60% of the material yield strength. For a deeper understanding of the failure, the relationship between hydrogen concentration and mechanical properties of the material, have been investigated with specimens prepared in order to simulate blade working conditions. A mechanical characterization of the material has been carried out by standard tensile testing in order to establish the effect of hydrogen content on the material strength. Further experimental activity was executed in order to characterize the fracture surface and to measure the hydrogen content. Finally, some of the failed blades have been analyzed in DICI-UNIPI laboratory. The experimental results show that the blades failure can be related with the hydrogen embrittlement phenomenon
Evolution of smart strategies and machines used for conservative management of herbaceous and horticultural crops in the mediterranean basin: a review
Preserving soil quality and increasing soil water availability is an important challenge to ensure food production for a growing global population. As demonstrated by several studies, conservative crop management, combined with soil cover and crop diversification, can significantly reduce soil and water losses. The aim of this review is to evaluate the spread of smart solutions to perform conservation agriculture (CA) well in the Mediterranean Basin, taking into account the evolution of the strategies and the machines used to perform conservative tillage systems in different contexts in the last 30 years, as well as the effects induced by their adoption on the productivity of herbaceous and horticultural crops, weed control and economic feasibility, in comparison with those obtained utilizing conventional techniques based on soil inversion
Evaluation of autonomous mowers weed control effect in globe artichoke field
The development of a fully automated robotic weeder is currently hindered by the lack of
a reliable technique for weed-crop detection. Autonomous mowers moving with random trajectories
rely on simplified computational resources and have shown potential when applied for agricultural
purposes. This study aimed to evaluate the applicability of these autonomous mowers for weed
control in globe artichoke. A first trial consisting of the comparison of the performances of three
different autonomous mowers (AM1, AM2 and AM3) was carried out evaluating percentage of
area mowed and primary energy consumption. The most suitable autonomous mower was tested
for its weed control effect and compared with a conventional weed management system. Average
weeds height, weed cover percentage, above-ground weed biomass, artichoke yield, primary energy
consumption and cost were assessed. All the autonomous mowers achieved a percentage of area
mowed around the 80% after 180 min. AM2 was chosen as the best compromise for weed control
in the artichoke field (83.83% of area mowed after 180 min of mowing, and a consumption of
430.50 kWh ha1 year1). The autonomous mower weed management achieved a higher weed
control effect (weed biomass of 71.76 vs. 143.67 g d.m. m2), a lower energy consumption (430.5 vs.
1135.13 kWh ha1 year1), and a lower cost (EUR 2601.84 vs. EUR 3661.80 ha1 year1) compared
to the conventional system
- …