88 research outputs found
An Empirical Examination of Why Mobile Money Schemes Ignite in Some Developing Countries but Flounder in Most
Mobile money schemes have grown rapidly in some developing countries but failed in many more. This paper reports the results of an empirical study of mobile money schemes in 22 developing countries chosen based on prior evidence to include roughly equal
The impact of bilingualism on executive functions in children and adolescents: a systematic review based on the PRISMA method
Approximately half of the world's population is bilingual or multilingual. The bilingual advantage theory claims that the constant need to control both known languages, that are always active in the brain, to use the one suitable for each specific context improves cognitive functions and specifically executive functions. However, some authors do not agree on the bilingual effect, given the controversial results of studies on this topic. This systematic review aims to summarize the results of studies on the relationship between bilingualism and executive functions. The review was conducted according to PRISMA-statement through searches in the scientific database PsychINFO, PsycARTICLES, MEDLINE, and PUBMED. Studies included in this review had at least one bilingual and monolingual group, participants aged between 5 and 17 years, and at least one executive function measure. Studies on second language learners, multilingual people, and the clinical population were excluded. Fifty-three studies were included in the systematic review. Evidence supporting the bilingual effect seems to appear when assessing inhibition and cognitive flexibility, but to disappear when working memory is considered. The inconsistent results of the studies do not allow drawing definite conclusions on the bilingual effect. Further studies are needed; they should consider the role of some modulators (e.g., language history and context, methodological differences) on the observed results
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
Robotic mowing of tall fescue at 90 mm cutting height: random trajectories vs. systematic trajectories
Tall fescue (Schedonorus arundinaceus (Schreb.) Dumort.) is often managed with a cutting height ranging from 70 to 100 mm in ornamental lawns. Some autonomous mowers have been specifically designed to maintain mowing height in the same range. Generally, autonomous mowers operate by following random trajectories, and substantial overlapping is needed to obtain full coverage of the working area. In the case of tall grass, this may cause lodging of grass plants, which in turn may reduce turf quality. The introduction of a navigation system based on systematic
trajectories has the potential to improve the performances of autonomous mowers with respect to machine efficiency and turf quality. With the aim of determining the effects of reduced mowing frequency and systematic navigation systems on turf quality and mower performances in terms of working time, energy consumption and overlapping, the performances of two autonomous mowers working with random and systematic trajectories were tested on a mature tall fescue lawn at 90 mm cutting height. The working efficiency was approximately 80% for the systematic trajectories and approximately 35% for the random trajectories; this was mainly due to the lower overlapping associated with systematic trajectories. Turf quality was slightly higher for the mower working systematically (a score of 8 using a 1–9 score with 1 = poor, 6 = acceptable and 9 = best) compared to the one working randomly (quality of 7 and 6 on a 1–9 scale with 1 = poor and 9 = best). No appreciable lodging was observed in either case. For tall, managed lawns, systematic trajectories may improve autonomous mowers’ overall performances
Autonomous Mowing and Complete Floor Cover for Weed Control in Vineyards
Enhancing vineyards sustainability and reducing herbicides usage is a crucial theme, thus
alternative weed management methods are starting to be studied. Cover crops have been shown to
provide for several environmental services such as performing an efficient weed control and promoting
biodiversity, thus improving the sustainability of the overall management system. However, the
use of cover crops is usually confined to the interrow area in order to avoid competition with vines.
Under-trellis weed management in vineyards is an important challenge, conventionally fulfilled
by cultivation or repeated herbicides applications. Autonomous mowers are small autonomous
machines that have shown a great efficiency when employed in agricultural contexts. Due to their
reduced size, they can easily prevent the excessive vertical growth of weeds both in the interrows
and under trellis without the use of chemical applications. The aim of this trial was to evaluate if the
combination of cover crop species and autonomous mowers management could improve vineyard
sustainability. Vineyard floor cover that was managed with an autonomous mower had a shorter
canopy height and a lower weed dry biomass compared to the conventionally managed vineyard
floor cover. Vineyard floor management providing cover crops and autonomous mowing had a
significantly lower weed cover percentage compared to conventional floor management, especially
under-trellis. The results of this trial suggest that the combination of cover crops and autonomous
mowers may be a sustainable and reliable technique to include in vineyards floor management
Assessment of the cutting performance of a robot mower using custom built software.
Before the introduction of positioning technologies in agriculture practices such as global
navigation satellite systems (GNSS), data collection and management were time-consuming and
labor-intensive tasks. Today, due to the introduction of advanced technologies, precise information
on the performance of agricultural machines, and smaller autonomous vehicles such as robot mowers,
can be collected in a relatively short time. The aim of this work was to track the performance of
a robot mower in various turfgrass areas of an equal number of square meters but with four dierent
shapes by using real-time kinematic (RTK)-GNSS devices, and to easily extract data by a custom built
software capable of calculating the distance travelled by the robot mower, the forward speed, the
cutting area, and the number of intersections of the trajectories. These data were then analyzed in
order to provide useful functioning information for manufacturers, entrepreneurs, and practitioners.
The path planning of the robot mower was random and the turfgrass area for each of the four shapes
was 135 m2 without obstacles. The distance travelled by the robot mower, the mean forward speed,
and the intersections of the trajectories were aected by the interaction between the time of cutting
and the shape of the turfgrass. For all the dierent shapes, the whole turfgrass area was completely cut
after two hours of mowing. The cutting eciency decreased by increasing the time, as a consequence
of the increase in overlaps. After 75 minutes of cutting, the eciency was about 35% in all the
turfgrass areas shapes, thus indicating a high level of overlapping
Trampling Analysis of Autonomous Mowers: Implications on Garden Designs
Several trials have been carried out by various authors concerning autonomous mowers, which are battery-powered machines. The effects of these machines on turfgrass quality and energy consumption have been thoroughly investigated. However, there are still some aspects that have not been studied. Among these, random trajectory overlapping is one of the most important. To investigate these aspects, two RTK-GPS devices along with the custom-built software used for previous trials has been upgraded in order to precisely calculate how many times the mower drives over the same spot using random trajectories. This parameter, the number of passages in the same position, was hypothesized to explain the autonomous mower's overlapping and trampling action. The trial has been carried out testing a commercial autonomous mower on three areas with different levels of complexity to assess its performances. The following variables were examined: the percentage of mowed area, the distance travelled, the number of intersections, the number of passages, and the autonomous mower's work efficiency. The average percentage of area mown (average value for the three areas) was 54.64% after one hour and 80.15% after two hours of work. Percentage of area mown was 15% higher for the area with no obstacles after two hours of work. The number of passages was slightly different among the three garden designs. The garden with no obstacles obtained the highest number of passages with an average of 37 passages. The highest working efficiency was obtained in the garden with an intermediate number of obstacles with a value of 0.40 after two hours of work. The estimated energy consumption resulted 0.31 Wh m(-2) after one hour and 0.42 Wh m(-2) after two hours of working. These results highlight how the correct settings of cutting time may be crucial to consistently save energy during the long period and may be useful for a complete automation of the maintenance of green areas
Hot foam and nitrogen application to promote spring transition of “Diamond” zoysiagrass (Zoysia matrella (L.) Merr.) overseeded with perennial ryegrass (Lolium perenne L.).
In transition areas, cool season turfgrasses are overseeded in autumn to maintain the high
quality of dormant warm season turfgrasses, while in spring several agronomic methods (scalping,
coring, topdressing, verticutting, irrigation, and targeted fertilization) or chemical desiccation are
adopted to remove the cool season turfgrasses from the stand. To reduce chemical applications,
several methods of “thermal weeding” have been experimented with, but little is known about
these methods in zoysiagrass (Zoysia spp. Willd) spring transition. A study was conducted at the
University of Pisa, Italy, on Manila grass (Zoysia matrella (L.) Merr., cv “Diamond”) (Zm) overseeded
with perennial ryegrass (Lolium perenne L.) (Lp) with the aim of comparing different methods of cool
season grass suppression (scalping and hot foam) and different application rates of nitrogen. To
assess treatment effect, green cover, turf quality, turf color, shoot density, and some vegetation indices
(GLI, DGCI and NDVI) were determined. An average green cover of at least 90% was obtained on all
plots seven weeks after the treatments. While scalping had minor effects on turf appearance and on
polystand composition, hot foam had a stronger effect on turf color, green cover, and turf quality in
the weeks following application. Once it had recovered from the hot foam treatments, the turf had a
greater number of Zm shoots and a relevant reduction of Lp shoots. The hot foam was very effective
in suppressing Lp while maintaining Zm recovery capacity.
quality of dormant warm season turfgrasses, while in spring several agronomic methods (scalping,
coring, topdressing, verticutting, irrigation, and targeted fertilization) or chemical desiccation are
adopted to remove the cool season turfgrasses from the stand. To reduce chemical applications,
several methods of “thermal weeding” have been experimented with, but little is known about
these methods in zoysiagrass (Zoysia spp. Willd) spring transition. A study was conducted at the
University of Pisa, Italy, on Manila grass (Zoysia matrella (L.) Merr., cv “Diamond”) (Zm) overseeded
with perennial ryegrass (Lolium perenne L.) (Lp) with the aim of comparing different methods of cool
season grass suppression (scalping and hot foam) and different application rates of nitrogen. To
assess treatment effect, green cover, turf quality, turf color, shoot density, and some vegetation indices
(GLI, DGCI and NDVI) were determined. An average green cover of at least 90% was obtained on all
plots seven weeks after the treatments. While scalping had minor effects on turf appearance and on
polystand composition, hot foam had a stronger effect on turf color, green cover, and turf quality in
the weeks following application. Once it had recovered from the hot foam treatments, the turf had a
greater number of Zm shoots and a relevant reduction of Lp shoots. The hot foam was very effective
in suppressing Lp while maintaining Zm recovery capacity
Comparison between different rotary mowing systems: Testing a new method to calculate turfgrass mowing quality
Poor quality in turfgrass mowing is highlighted by the shredded leaf tips with necrotic tissues that give an unsightly brownish colour to the turf and may also lead to turf disease. Mowing quality is also typically assessed by visual rating, thus the score depends on the person doing the assessment. To make the evaluation of mowing quality not subjective, an innovative method was developed. The aim of the trial was to examine the effects of different mowing systems and two different nitrogen rates (100 and 200 kg ha−1 ) on two turfgrass species in order to test the new mowing quality calculation. Three different mowing systems were used: a battery-powered rotary mower set at 3000 rpm and 5000 rpm respectively and a gasoline-powered rotary mower set at full throttle. The battery-powered mower at low blade rpm produced a poorer mowing quality and turf quality than the gasoline-powered mower and battery-powered mower at high rpm, which produced a similar mowing quality and turf quality. Leaf tip damage level values showed a significant correlation with the results of the visual mowing quality assessment. Lower leaf tip damage level values (slightly above 1) corresponded to higher visual mowing quality scores (around 8)
Glucose Abnormalities Associated to Prolactin Secreting Pituitary Adenomas
The pathogenesis of obesity and alterations in glucose profile have been linked to PRL excess, as it is reportedly associated with metabolic syndrome in thereabout one third of patients. In vitro exposure of pancreatic islet to PRL is known to stimulate insulin secretion and β-cell proliferation, and in turn overexpression of PRL in β-cells increases insulin release and β-cell replication. PRL excess has been found to worsen glucose profile because it reduces glucose tolerance and induces insulin resistance either in obese and non-obese patients. To note, pancreatic β-cells and adipocytes widely express dopamine receptors type 2, and dopamine has been hypothesized to play a key role as modulator of insulin and adipose functions. The dopamine agonists bromocriptine and cabergoline significantly improve abnormalities in glucose profile and reduce the prevalence of metabolic syndrome in a remarkable proportion of patients, regardless of whether body weight and PRL status may change. However, in men with hyperprolactinemia complicated by hypogonadism, testosterone replacement can ameliorate insulin resistance and abnormalities in glucose metabolism. Therefore, in patients with PRL-secreting pituitary adenomas control of PRL excess by dopamine agonists is mandatory to improve glucose and insulin abnormalities
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