8,702 research outputs found
From Bullettino della Società Botanica Italiana to Italian Botanist, passing through Informatore Botanico Italiano. A 128 years–long story
In 1888, concomitant with the foundation of the Italian Botanical Society, a section
called Bullettino della SocietĂ Botanica Italiana appeared in the last pages of each issue
of volume 20 of the Nuovo Giornale Botanico Italiano (currently the international
journal Plant Biosystems)...
Inflammation, neurodegeneration and protein aggregation in the retina as ocular biomarkers for Alzheimer’s Disease in the 3xTg-AD mouse model
Alzheimer's disease (AD) is the most common cause of dementia in the elderly. In the pathogenesis of AD a pivotal role is played by two neurotoxic proteins that aggregate and accumulate in the central nervous system: amyloid beta and hyper-phosphorylated tau. Accumulation of extracellular amyloid beta plaques and intracellular hyper-phosphorylated tau tangles, and consequent neuronal loss begins 10-15 years before any cognitive impairment. In addition to cognitive and behavioral deficits, sensorial abnormalities have been described in AD patients and in some AD transgenic mouse models. Retina can be considered a simple model of the brain, as some pathological changes and therapeutic strategies from the brain may be observed or applicable to the retina. Here we propose new retinal biomarkers that could anticipate the AD diagnosis and help the beginning and the follow-up of possible future treatments. We analyzed retinal tissue of triple-transgenic AD mouse model (3xTg-AD) for the presence of pathological hallmarks during disease progression. We found the presence of amyloid beta plaques, tau tangles, neurodegeneration, and astrogliosis in the retinal ganglion cell layer of 3xTg-AD mice, already at pre-symptomatic stage. Moreover, retinal microglia in pre-symptomatic mice showed a ramified, anti-inflammatory phenotype which, during disease progression, switches to a pro-inflammatory, less ramified one, becoming neurotoxic. We hypothesize retina as a window through which monitor AD-related neurodegeneration process
Checklist della flora vascolare psammofila della Toscana
Checklist of the psammophilous vascular flora of Tuscany. An updated list of the psammophilous vascular flora occurring in coastal areas of Tuscany is presented. The list is based on bibliographic analysis and field studies effected ad hoc in the year 2012-2013. 704 specific and infraspecific taxa are reported (641 native). They belong to 383 genera and 90 families. Most represented families are Poaceae (13%), Asteraceae (12%), Fabaceae (10%), Caryophyllaceae (5%), Apiaceae (4%). 63 units are naturalized exotic species (about 9% of the flora). Aloe arborescens is a casual exotic newly recorded for Tuscany. The Italian endemics are 6, of which three are exclusive of sandy Tuscan coasts (Centaurea aplolepa Moretti subsp. subciliata (DC.) Arcang., Limonium etruscum Arrigoni & Rizzotto, Solidago litoralis Savi). Only 11 taxa were recorded in all or almost all the study areas: Ammophila arenaria (L.) Link subsp. arundinacea H.Lindb, Cakile maritima Scop. subsp. maritima, Calystegia soldanella (L.) Roem. & Schult., Echinophora spinosa L., Eryngium maritimum L., Kali tragus (L.) Scop. s.l., Lagurus ovatus L. subsp. ovatus, Medicago marina L., Pancratium maritimum L., Sporobolus virginicus Kunth
Finite element analysis applied to redesign of submerged entry nozzles for steelmaking
The production of steel by continuous casting is facilitated by the use of refractory hollow-ware components. A critical component in this process is the submerged entry nozzle (SEN). The normal operating conditions of the SEN are arduous, involving large temperature gradients and exposure to mechanical forces arising from the flow of molten steel; experimental development of the components is challenging in so hazardous an environment. The effects of the thermal stress conditions in relation to a well-tried design were therefore simulated using a finite element analysis approach. It was concluded from analyses that failures of the type being experienced are caused by the large temperature gradient within the nozzle. The analyses pointed towards a supported shoulder area of the nozzle being most vulnerable to failure and practical in-service experience confirmed this. As a direct consequence of the investigation, design modifications, incorporating changes to both the internal geometry and to the nature of the intermediate support material, were implemented, thereby substantially reducing the stresses within the Al2O3/graphite ceramic liner. Industrial trials of this modified design established that the component reliability would be significantly improved and the design has now been implemented in series production
On the influence of collinear surface waves on turbulence in smooth-bed open-channel flows
This work investigates how turbulence in open-channel flows is altered by the passage of surface waves by using experimental data collected with laboratory tests in a large-scale flume facility, wherein waves followed a current. Flow velocity data were measured with a laser Doppler anemometer and used to compute profiles of mean velocity and Reynolds stresses, and pre-multiplied spectra. The velocity signal containing contributions from the mean flow, wave motion and turbulence was decomposed using the empirical mode decomposition (EMD), which is considered a promising tool for the analysis of velocity time series measured in complex flows. A novel outer length scale h0 is proposed which separates the flow into two regions depending on the competition between the vertical velocities associated with the wave motion and the turbulent velocities imposed by the current. This outer length scale allows for the identification of a genuine overlap layer and an insightful scaling of turbulent statistics in the current-dominated flow region (i.e. y/h0 > 1), a new spectral signature associated with long turbulent structures (approximately 6 and 25 times the flow depth h). As the wave contribution to the vertical velocity increases, the pre-multiplied spectra reveal two intriguing features: (i) in the current-dominated flow region, the very large-scale motions (VLSMs) are progressively weakened but attached eddies are still present; and (ii) in the wave-dominated flow region (i.e. 1$]) appears. These longitudinal structures present in the wave-dominated flow region seem to share many features with Langumir-type cells
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
Heavy metal distribution in a sediment phytoremediation system at pilot scale
The continuous stream of polluted sediments, dredged from harbors and water bodies in order to maintain the navigation, is a common practice, but the fate of these sediments is an issue recognized worldwide. This pilot case study evaluated the application of phytoremediation as sustainable management strategy for the decontamination of polluted dredged marine sediments. The synergic action of different plant species (Paspalum vaginatum; P. vaginatum + Spartium junceum and P. vaginatum + Tamarix gallica) and organic matter (compost) in removing both heavy metals (Cd, Ni, Zn, Pb and Cu) and total petroleum hydrocarbons, and in recovering the nutritive and biological sediment properties were evaluated. In addition to the detection of total metal removal efficiency, the chemical distribution of metals in the sediment phases (exchangeable, manganese and iron oxides, organic matter and residual minerals) was also measured in order to make a more realistic estimation of the phytoremediation efficiency for the sediment decontamination. Finally, a complete picture of the metal flux was obtained by investigating the metal mass-balance in the treated sediments. The results of metal content in the sediment phases showed that metal distribution was not uniform and each metal predominated in different fractions; the solubility of metals in the sediment in the decreasing order was: Cd>Zn>Cu>Pb>Ni. The higher proportion of Ni and Pb in the residual phase can be the reason of the lower translocation of these metals in the plant tissues. On the other hand, Cd, Zn and Cu were the metals most easily translocated in plant tissues, both aboveground and roots, confirming their higher availability for the plants.
The results of mass balance indicated that, at the end of the experimentation, a high content of metals were still found in the sediment. The greatest contribution in metal removal was attributed to a phytostabilization process at rhizosphere level followed by gravel and sand absorption. The capacity of rhizophere to precipitate heavy metals, could be considered as an alternative option for reducing the metal availability and, consequently, the toxicity in contaminated sediments
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
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
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