895 research outputs found
Produzioni casearie tradizionali : qualit\ue0 microbiologica e sicurezza d\u2019uso
Il settore alimentare \ue8 regolamentato da un pacchetto legislativo di recente emanazione che disciplina l\u2019igiene del prodotto, intesa come salubrit\ue0 e sicurezza d\u2019uso. L\u2019introduzione di rigide misure igieniche pu\uf2 per\uf2 determinare radicali mutamenti nel processo produttivo che, a loro volta, possono incidere anche drasticamente sulle caratteristiche originarie di prodotti artigianali che maggiormente rappresentano l\u2019espressione storico-culturale di un territorio.
Un esempio \ue8 rappresentato dalla sostituzione di materiali tradizionali quali, rame e legno, con altri igienicamente pi\uf9 idonei come l\u2019acciaio inox, possono portare a significative variazioni sensoriali del prodotto finale. Nell\u2019ottica della salvaguardia dei prodotti tipici, a fronte della necessit\ue0 di disporre di un sistema produttivo igienico e sicuro, come richiesto dalla normativa vigente, ci parso inportante valutare quali elementi possono essere mantenuti per la caratterizzazione del prodotto.
In questo lavoro si \ue8 valutata la qualit\ue0 microbiologica di formaggi dalla materia prima fino al prodotto finito, prodotti in tre diverse realt\ue0 di montagna site in Valsesia. Sui campioni prelevati sterilmente ad ogni fase della lavorazione, sono stati ricercati i seguenti indicatori di qualit\ue0:
\u2022 Conta dei contaminanti
\u2022 Coliformi totati e fecali
\u2022 Batteri lattici totali
\u2022 Micrococcaceae
\u2022 Enterococchi
\u2022 Eumiceti totali
Come indicatori di sicurezza d\u2019uso sono invece stati ricercati, limitatamente al prodotto finito, Listeria monocytogenes, Salmonella spp. e Staphylococcus aureus.
I risultati delle conte microbiche non hanno evidenziato, per lo meno a livello qualitativo, significative differenze tra le varie realt\ue0.
La situazione igienica \ue8 apparsa decisamente confortante, infatti sono sempre risultati assenti i patogeni ricercati sia a livello del prodotto sia nell\u2019ambiente. La microflora autoctona \ue8 apparsa rappresentata principalmente da cocchi lattici omofermentanti che, gi\ue0 nel latte rappresentano la componente maggioritaria. I lieviti e le micrococcaceae iniziano a diventare significativi dalla salatura in poi: la loro presenza non \ue8 da ritenere negativa in quanto, caratterizzati da spiccate attivit\ue0 proteolitica e soprattutto lipolitica, intervengono positivamente sulle caratteristiche organolettiche del prodotto finito. Le muffe ritrovate provengono prevalentemente dalla crosta e sono associate alle differenti ecologie dei locali di stagionatura. Dalle piastre sono stati isolati numerosi ceppi che saranno sottoposti a identificazione sino a livello molecolaree su ciascuno saranno valutate le attivit\ue0 enzimatiche al fine di effettuare una selezione dei ceppi pi\uf9 utili per il conseguimento di un prodotto finito che possegga tutte quelle caratteristiche che il consumatore associa al prodotto artigianale di qualit\ue0
Recent trends and advances in microbial electrochemical sensing technologies: An overview
Microbial electrochemical systems utilize the electrochemical interaction between microorganisms and electrode surfaces to convert chemical energy into electrical energy, offering a promise as technologies for wastewater treatment, bioremediation, and biofuel production. Recently, growing research attention has been devoted to the development of microbial electrochemical sensrs as biosensing platforms. Microbial electrochemical sensors are a type of microbial electrochemical technology (MET) capable of sensing through the anodic or the cathodic electroactive microorganisms and/or biofilms. Herein, we review and summarize the recent advances in the design of microbial electrochemical sensing approaches with a specific overview and discussion of anodic and cathodic microbial electrochemical sensor devices, highlighting both the advantages and disadvantages. Particular emphasis is given on the current trends and strategies in the design of low-cost, convenient, efficient, and high performing METs with different biosensing applications, including toxicity monitoring, pathogen detection, corrosion monitoring, as well as measurements of biological oxygen demand, chemical oxygen demand, and dissolved oxygen. The conclusion provides perspectives and an outlook to understand the shortcomings in the design, development status, and sensing applications of microbial electrochemical platforms. Namely, we discuss key challenges that limit the practical implementation of METs for sensing purposes and deliberate potential solutions, necessary developments, and improvements in the field
Euclid Space Mission: building the sky survey
The Euclid space mission proposes to survey 15000 square degrees of the
extragalactic sky during 6 years, with a step-and-stare technique. The
scheduling of observation sequences is driven by the primary scientific
objectives, spacecraft constraints, calibration requirements and physical
properties of the sky. We present the current reference implementation of the
Euclid survey and on-going work on survey optimization.Comment: to appear in Proceedings IAU Symposium No. 306, "Statistical
Challenges in 21st Century Cosmology", A.F. Heavens, J.-L. Starck & A.
Krone-Martins, ed
Quality of Life, Wishes, and Needs in Women with Gestational Diabetes: Italian DAWN Pregnancy Study
The DAWN (Diabetes Attitudes, Wishes and Needs) study is a survey promoted by the International Diabetes Federation to recognize the perceptions and attitudes of people suffering from diabetes mellitus. In this context, we evaluated the quality of life of Italian and immigrant women with gestational diabetes mellitus (GDM). Information was gathered using a structured questionnaire for patients' self-compilation. In a 3-month period, a 51-item questionnaire was submitted to 198 Italians and 88 immigrants (from 27 different foreign nationalities). Italian women were older and had higher education than the immigrants. 60% of the Italians and 38% of the immigrants had a family history of diabetes mellitus. In both groups, the diagnosis of GDM caused anxiety; one-third of women feared their child could contract diabetes at delivery and/or have congenital malformations. Some women had trouble in following treatment regimens: the major concern being dietary advice and blood glucose testing. Most women were satisfied (34%) or highly satisfied (60%) with the quality of care, although the degree of cooperation between diabetes specialists and gynaecologists was considered sometimes unsatisfactory. In order to optimize maternal and foetal outcomes, educational projects and improved communication between patients and the healthcare provider team are recommended
Evaluation and predictive modeling of shelf life of minced beef meat stored in high-oxygen modified atmosphere packaging at different temperatures
The aims were: (1) to follow the freshness decay of minced beef stored in high-oxygen modified atmosphere packaging at different temperatures (4.3, 8.1 and 15.5 \ub0C) by applying traditional methods (microbiological counts, color evaluation, thiobarbituric acid assay TBA, headspace gas composition) and e-nose; (2) to model the decay kinetics to obtain information about the maximum shelf life as function of storage conditions. The minced beef, packaged in modified atmosphere was supplied by a manufacturer at the beginning of its commercial life. The study demonstrated the ability of the traditional methods to describe the kinetics of freshness decay. The modeling of the experimental data and the comparison with microbiological or chemical thresholds allowed the setting, for each index, of a stability time above which the meat was no longer acceptable. The quality decay of meat was also evaluated by the headspace fingerprint of the same set of samples by means of a commercial e-nose. A clear discrimination between \u201cfresh\u201d and \u201cold\u201d samples was obtained using PCA and CA, determining at each temperature a specific range of stability time. The mean value of the stability times calculated for each index was 9 days at 4.3 \ub0C (recommended storage temperature), 3\u20134 days at 8.1 \ub0C (usual temperature in household refrigerators) and 2 days at 15.5 \ub0C (abuse temperature). Resolution of the stability times allowed calculation of mean Q10 values, i.e. the increase in rate for a 10 \ub0C increase in temperature.
The results show that the Q10 values from the traditional methods (3.6\u20134.0 range) overlapped with those estimated with e-nose and color indexes (3.4 and 3.9, respectively)
A new method to separate star forming from AGN galaxies at intermediate redshift: The submillijansky radio population in the VLA-COSMOS survey
We explore the properties of the submillijansky radio population at 20 cm by
applying a newly developed optical color-based method to separate star forming
(SF) from AGN galaxies at intermediate redshifts (z<1.3). Although optical
rest-frame colors are used, our separation method is shown to be efficient, and
not biased against dusty starburst galaxies. This classification method has
been calibrated and tested on a local radio selected optical sample. Given
accurate multi-band photometry and redshifts, it carries the potential to be
generally applicable to any galaxy sample where SF and AGN galaxies are the two
dominant populations.
In order to quantify the properties of the submillijansky radio population,
we have analyzed ~2,400 radio sources, detected at 20 cm in the VLA-COSMOS
survey. 90% of these have submillijansky flux densities. We classify the
objects into 1) star candidates, 2) quasi stellar objects, 3) AGN, 4) SF, and
5) high redshift (z>1.3) galaxies. We find, for the composition of the
submillijansky radio population, that SF galaxies are not the dominant
population at submillijansky flux levels, as previously often assumed, but that
they make up an approximately constant fraction of 30-40% in the flux density
range of ~50 microJy to 0.7 mJy. In summary, based on the entire VLA-COSMOS
radio population at 20 cm, we find that the radio population at these flux
densities is a mixture of roughly 30-40% of SF and 50-60% of AGN galaxies, with
a minor contribution (~10%) of QSOs.Comment: 26 pages, 26 figures; accepted for publication in ApJ
Extreme emission-line galaxies out to z1 in zCOSMOS. I. Sample and characterization of global properties
We present a thorough characterization of a large sample of 183 extreme
emission-line galaxies (EELGs) at redshift 0.11 < z < 0.93 selected from the
20k zCOSMOS Bright Survey because of their unusually large emission line
equivalent widths. We use multiwavelength COSMOS photometry, HST-ACS I-band
imaging and optical zCOSMOS spectroscopy to derive the main global properties
of EELGs, such as sizes, masses, SFRs, reliable metallicities from both
"direct" and "strong-line" methods. The EELGs are compact (R_50 ~ 1.3 kpc),
low-mass (log(M*/Msol)~7-10) galaxies forming stars at unusually high specific
SFR (log(sSFR/yr) up to ~ -7) compared to main sequence SFGs of the same
stellar mass and redshift. At UV wavelengths, the EELGs are luminous and show
high surface brightness and include strong Ly emitters, as revealed by
GALEX spectroscopy. We show that zCOSMOS EELGs are high-ionization,
low-metallicity systems, with median 12+log(O/H)=8.16, including a handful of
extremely metal-deficient galaxies (<10% solar). While ~80% of the EELGs show
non-axisymmetric morphologies, including clumpy and tadpole galaxies, we find
that ~29% of them show additional low surface-brightness features, which
strongly suggest recent or ongoing interactions. As star-forming dwarfs in the
local Universe, EELGs are most often found in relative isolation. While only
very few EELGs belong to compact groups, almost one third of them are found in
spectroscopically confirmed loose pairs or triplets. We conclude that EELGs are
galaxies caught in a transient and probably early period of their evolution,
where they are efficiently building-up a significant fraction of their
present-day stellar mass in an ongoing galaxy-wide starburst. Therefore, the
EELGs constitute an ideal benchmark for comparison studies between low- and
high-redshift low-mass star-forming galaxies.Comment: Accepted in A&A. Final replacement to match the version in press. It
includes a minor change in the title and a new figur
The VIMOS Public Extragalactic Redshift Survey (VIPERS). Never mind the gaps: comparing techniques to restore homogeneous sky coverage
[Abridged] Non-uniform sampling and gaps in sky coverage are common in galaxy
redshift surveys, but these effects can degrade galaxy counts-in-cells and
density estimates. We carry out a comparison of methods that aim to fill the
gaps to correct for the systematic effects. Our study is motivated by the
analysis of the VIMOS Extragalactic Redshift Survey (VIPERS), a flux-limited
survey (i<22.5) based on one-pass observations with VIMOS, with gaps covering
25% of the surveyed area and a mean sampling rate of 35%. Our findings are
applicable to other surveys with similar observing strategies. We compare 1)
two algorithms based on photometric redshift, that assign redshifts to galaxies
based on the spectroscopic redshifts of the nearest neighbours, 2) two Bayesian
methods, the Wiener filter and the Poisson-Lognormal filter. Using galaxy mock
catalogues we quantify the accuracy of the counts-in-cells measurements on
scales of R=5 and 8 Mpc/h after applying each of these methods. We also study
how they perform to account for spectroscopic redshift error and inhomogeneous
and sparse sampling rate. We find that in VIPERS the errors in counts-in-cells
measurements on R<10 Mpc/h scales are dominated by the sparseness of the
sample. All methods underpredict by 20-35% the counts at high densities. This
systematic bias is of the same order as random errors. No method outperforms
the others. Random and systematic errors decrease for larger cells. We show
that it is possible to separate the lowest and highest densities on scales of 5
Mpc/h at redshifts 0.5<z<1.1, over a large volume such as in VIPERS survey.
This is vital for the characterisation of cosmic variance and rare populations
(e.g, brightest galaxies) in environmental studies at these redshifts.Comment: 17 pages, 13 figures, accepted for publication in A&A (revised
version after minor revision and language editing
Euclid space mission: a cosmological challenge for the next 15 years
Euclid is the next ESA mission devoted to cosmology. It aims at observing
most of the extragalactic sky, studying both gravitational lensing and
clustering over 15,000 square degrees. The mission is expected to be
launched in year 2020 and to last six years. The sheer amount of data of
different kinds, the variety of (un)known systematic effects and the complexity
of measures require efforts both in sophisticated simulations and techniques of
data analysis. We review the mission main characteristics, some aspects of the
the survey and highlight some of the areas of interest to this meetingComment: to appear in Proceedings IAU Symposium No. 306, 2014, "Statistical
Challenges in 21st Century Cosmology", A.F. Heavens, J.-L. Starck & A.
Krone-Martins, ed
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