132 research outputs found
In vitro and in vivo selection of potentially probiotic lactobacilli from Nocellara del Belice table olives
Table olives are increasingly recognized as a vehicle as well as a source of probiotic bacteria, especially those fermented with traditional procedures based on the activity of indigenous microbial consortia, originating from local environments. In the present study, we report characterization at the species level of 49 Lactic Acid Bacteria (LAB) strains deriving from Nocellara del Belice table olives fermented with the Spanish or Castelvetrano methods, recently isolated in our previous work. Ribosomal 16S DNA analysis allowed identification of 4 Enterococcus gallinarum, 3 E. casseliflavus, 14 Leuconostoc mesenteroides, 19 Lactobacillus pentosus, 7 L. coryniformis, and 2 L. oligofermentans. The L. pentosus and L. coryniformis strains were subjected to further screening to evaluate their probiotic potential, using a combination of in vitro and in vivo approaches. The majority of them showed high survival rates under in vitro simulated gastro-intestinal conditions, and positive antimicrobial activity against Salmonella enterica serovar Typhimurium, Listeria monocytogenes and enterotoxigenic Escherichia coli (ETEC) pathogens. Evaluation of antibiotic resistance to ampicillin, tetracycline, chloramphenicol, or erythromycin was also performed for all selected strains. Three L. coryniformis strains were selected as very good performers in the initial in vitro testing screens, they were antibiotic susceptible, as well as capable of inhibiting pathogen growth in vitro. Parallel screening employing the simplified model organism Caenorhabditis elegans, fed the Lactobacillus strains as a food source, revealed that one L. pentosus and one L. coryniformis strains significantly induced prolongevity effects and protection from pathogen-mediated infection. Moreover, both strains displayed adhesion to human intestinal epithelial Caco-2 cells and were able to outcompete foodborne pathogens for cell adhesion. Overall, these results are suggestive of beneficial features for novel LAB strains, which renders them promising candidates as starters for the manufacturing of fermented table olives with probiotic added value
Monitoring of the tractor working parameters from the Can-Bus.
The analysis of the tractor mission profile is one of the main objectives for tractor manufacturers. The mission profile has usually been estimated through the use of questionnaires submitted to consumers. This procedure is time-consuming and not totally reliable due to the trustworthiness in the questionnaire compilation. In all the high power tractors numerous transducers are fitted to monitor some parameters to optimise the operation of the machines. All of these transducers are connected to an electronic central unit or with the tractor CAN-Bus. In this context, a system able to monitor the working parameters of the machines capitalising the existing transducers could represent the optimal solution for monitoring tractors distributed in different regions. The high number of signals are in any case difficult to memorise without a high quantity of memory. The goal of the paper is to define a methodology to memorise the operation parameters useful to define the mission profile of a tractor using a small memory. A tractor of a nominal power of 230 kW was selected and a system able to measure the signals acquired by the transducers fitted on the tractor was connected to the CAN Bus of the tractor. After a detailed analysis of the parameters measured on the tractor, the useful parameters were defined and acquired in different working conditions. The analysis of the parameters stored in the memory has allowed a detailed analysis of the operational parameters of the tractor in different applications. These parameters could be used by engineers to design tractors with a higher quality and reliability and also to define predictive maintenance criteria and reduce unexpected tractor failures
Low delta-V near-Earth asteroids: A survey of suitable targets for space missions
In the last decades Near-Earth Objects (NEOs) have become very important
targets to study, since they can give us clues to the formation, evolution and
composition of the Solar System. In addition, they may represent either a
threat to humankind, or a repository of extraterrestrial resources for suitable
space-borne missions. Within this framework, the choice of next-generation
mission targets and the characterisation of a potential threat to our planet
deserve special attention. To date, only a small part of the 11,000 discovered
NEOs have been physically characterised. From ground and space-based
observations one can determine some basic physical properties of these objects
using visible and infrared spectroscopy. We present data for 13 objects
observed with different telescopes around the world (NASA-IRTF, ESO-NTT, TNG)
in the 0.4 - 2.5 um spectral range, within the NEOSURFACE survey
(http://www.oa-roma.inaf.it/planet/NEOSurface.html). Objects are chosen from
among the more accessible for a rendez-vous mission. All of them are
characterised by a delta-V (the change in velocity needed for transferring a
spacecraft from low-Earth orbit to rendez-vous with NEOs) lower than 10.5 km/s,
well below the Solar System escape velocity (12.3 km/s). We taxonomically
classify 9 of these objects for the first time. 11 objects belong to the
S-complex taxonomy; the other 2 belong to the C-complex. We constrain the
surface composition of these objects by comparing their spectra with meteorites
from the RELAB database. We also compute olivine and pyroxene mineralogy for
asteroids with a clear evidence of pyroxene bands. Mineralogy confirms the
similarity with the already found H, L or LL ordinary chondrite analogues.Comment: 9 pages, 7 figures, to be published in A&A Minor changes by language
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On the deflection of asteroids with mirrors
This paper presents an analysis of an asteroid deflection method based on multiple solar concentrators. A model of the deflection through the sublimation of the surface material of an asteroid is presented, with simulation results showing the achievable orbital deflection with, and without, accounting for the effects of mirror contamination due to the ejected debris plume. A second model with simulation results is presented analyzing an enhancement of the Yarkovsky effect, which provides a significant deflection even when the surface temperature is not high enough to sublimate. Finally the dynamical model of solar concentrators in the proximity of an irregular celestial body are discussed, together with a Lyapunov-based controller to maintain the spacecraft concentrators at a required distance from the asteroid
The NEOShield-2 EU project: The Italian contribution
The NEOShield-2 (2015-2017) project has been recently approved by the European Commission in the framework of the Horizon 2020 programme with the aim i) to study specific technologies and instruments to conduct close approach missions to NEOs or to undertake mitigation demonstration, and ii) to acquire in-depth information of physical properties of the population of small NEOs (50-300 m), in order to design mitigation missions and assess the consequences of an impact on Earth. The Italian scientific community is widely involved in this project
Photometric survey of 67 near-Earth objects
Context. The near-Earth object (NEO) population is a window into the original conditions of the protosolar nebula, and has the potential to provide a key pathway for the delivery of water and organics to the early Earth. In addition to delivering the crucial ingredients for life, NEOs can pose a serious hazard to humanity since they can impact the Earth. To properly quantify the impact risk, physical properties of the NEO population need to be studied. Unfortunately, NEOs have a great variation in terms of mitigation-relevant quantities (size, albedo, composition, etc.) and less than 15% of them have been characterized to date. Aims. There is an urgent need to undertake a comprehensive characterization of smaller NEOs (D < 300 m) given that there are many more of them than larger objects; their small sizes make them intrinsically fainter and therefore harder to study. One of the main aims of the NEOShield-2 project (2015-2017), financed by the European Community in the framework of the Horizon 2020 program, is therefore to retrieve physical properties of a wide number of NEOs in order to design impact mitigation missions and assess the consequences of an impact on Earth. Methods. We carried out visible photometry of NEOs, making use of the DOLORES instrument at the Telescopio Nazionale Galileo (TNG, La Palma, Spain) in order to derive visible color indexes and the taxonomic classification for each target in our sample. Results. We attributed for the first time the taxonomical complex of 67 objects obtained during the first year of the project. While the majority of our sample belong to the S-complex, carbonaceous C-complex NEOs deserve particular attention. These NEOs can be located in orbits that are challenging from a mitigation point of view, with high inclination and low minimum orbit intersection distance (MOID). In addition, the lack of carbonaceous material we see in the small NEO population might not be due to an observational bias alone
Statistically Significant Detection of Linguistic Change
We propose a new computational approach for tracking and detecting
statistically significant linguistic shifts in the meaning and usage of words.
Such linguistic shifts are especially prevalent on the Internet, where the
rapid exchange of ideas can quickly change a word's meaning. Our meta-analysis
approach constructs property time series of word usage, and then uses
statistically sound change point detection algorithms to identify significant
linguistic shifts.
We consider and analyze three approaches of increasing complexity to generate
such linguistic property time series, the culmination of which uses
distributional characteristics inferred from word co-occurrences. Using
recently proposed deep neural language models, we first train vector
representations of words for each time period. Second, we warp the vector
spaces into one unified coordinate system. Finally, we construct a
distance-based distributional time series for each word to track it's
linguistic displacement over time.
We demonstrate that our approach is scalable by tracking linguistic change
across years of micro-blogging using Twitter, a decade of product reviews using
a corpus of movie reviews from Amazon, and a century of written books using the
Google Book-ngrams. Our analysis reveals interesting patterns of language usage
change commensurate with each medium.Comment: 11 pages, 7 figures, 4 table
The effect of seasoning with herbs on the nutritional, safety and sensory properties of reduced-sodium fermented Cobrançosa cv. table olives
This study aimed at evaluating the effectiveness of seasoning Cobrancosa table olives in a brine with aromatic ingredients, in order to mask the bitter taste given by KCl when added to reduced-sodium fermentation brines. Olives were fermented in two different salt combinations: Brine A, containing 8% NaCl and, Brine B, a reduced-sodium brine, containing 4% NaCl + 4% KCl. After the fermentation the olives were immersed in seasoning brines with NaCl (2%) and the aromatic herbs (thyme, oregano and calamintha), garlic and lemon. At the end of the fermentation and two weeks after seasoning, the physicochemical, nutritional, organoleptic, and microbiological parameters, were determined. The olives fermented in the reduced-sodium brines had half the sodium concentration, higher potassium and calcium content, a lower caloric level, but were considered, by a sensorial panel, more bitter than olives fermented in NaCl brine. Seasoned table olives, previously fermented in Brine A and Brine B, had no significant differences in the amounts of protein (1.23% or 1.11%), carbohydrates (1.0% or 0.66%), fat (20.0% or 20.5%) and dietary fiber (3.4% or 3.6%). Regarding mineral contents, the sodium-reduced fermented olives, presented one third of sodium, seven times more potassium and three times more calcium than the traditional olives fermented in 8% NaCl. Additionally, according to the panelists' evaluation, seasoning the olives fermented in 4% NaCl + 4% KCl, resulted in a decrease in bitterness and an improvement in the overall evaluation and flavor. Escherichia coli and Salmonella were not found in the olives produced.info:eu-repo/semantics/publishedVersio
Antibiotic resistance determinants in the interplay between food and gut microbiota
A complex and heterogeneous microflora performs sugar and lactic acid fermentations in food products. Depending on the fermentable food matrix (dairy, meat, vegetable etc.) as well as on the species composition of the microbiota, specific combinations of molecules are produced that confer unique flavor, texture, and taste to each product. Bacterial populations within such “fermented food microbiota” are often of environmental origin, they persist alive in foods ready for consumption, eventually reaching the gastro-intestinal tract where they can interact with the resident gut microbiota of the host. Although this interaction is mostly of transient nature, it can greatly contribute to human health, as several species within the food microbiota also display probiotic properties. Such an interplay between food and gut microbiota underlines the importance of the microbiological quality of fermented foods, as the crowded environment of the gut is also an ideal site for genetic exchanges among bacteria. Selection and spreading of antibiotic resistance genes in foodborne bacteria has gained increasing interest in the past decade, especially in light of the potential transferability of antibiotic resistance determinants to opportunistic pathogens, natural inhabitants of the human gut but capable of acquiring virulence in immunocompromised individuals. This review aims at describing major findings and future prospects in the field, especially after the use of antibiotics as growth promoters was totally banned in Europe, with special emphasis on the application of genomic technologies to improve quality and safety of fermented foods
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