3,153 research outputs found
Escherichia coli contamination and health aspects of soil and tomatoes (Solanum lycopersicum L.) subsurface drip irrigated with on-site treated domestic wastewater.
Faecal contamination of soil and tomatoes irrigated by sprinkler as well as surface and subsurface drip irrigation with treated domestic wastewater were compared in 2007 and 2008 at experimental sites in Crete and Italy. Wastewater was treated by Membrane Bio Reactor (MBR) technology, gravel filtration or UV-treatment before used for irrigation. Irrigation water, soil and tomato samples were collected during two cropping seasons and enumerated for the faecal indicator bacterium Escherichia coli and helminth eggs. The study found elevated levels of E. coli in irrigation water (mean: Italy 1753 cell forming unit (cfu) per 100 ml and Crete 488 cfu per 100 ml) and low concentrations of E. coli in soil (mean: Italy 95 cfu g(-1) and Crete 33 cfu g(-1)). Only two out of 84 tomato samples in Crete contained E. coli (mean: 2700 cfu g(-1)) while tomatoes from Italy were free of E. coli. No helminth eggs were found in the irrigation water or on the tomatoes from Crete. Two tomato samples out of 36 from Italy were contaminated by helminth eggs (mean: 0.18 eggs g(-1)) and had been irrigated with treated wastewater and tap water, respectively. Pulsed Field Gel Electrophoresis DNA fingerprints of E. coli collected during 2008 showed no identical pattern between water and soil isolates which indicates contribution from other environmental sources with E. coli, e.g. wildlife. A quantitative microbial risk assessment (QMRA) model with Monte Carlo simulations adopted by the World Health Organization (WHO) found the use of tap water and treated wastewater to be associated with risks that exceed permissible limits as proposed by the WHO (1.0 Ă 10(-3) disease risk per person per year) for the accidental ingestion of irrigated soil by farmers (Crete: 0.67 pppy and Italy: 1.0 pppy). The QMRA found that the consumption of tomatoes in Italy was deemed to be safe while permissible limits were exceeded in Crete (1.0 pppy). Overall the quality of tomatoes was safe for human consumption since the disease risk found on Crete was based on only two contaminated tomato samples. It is a fundamental limitation of the WHO QMRA model that it is not based on actual pathogen numbers, but rather on numbers of E. coli converted to estimated pathogen numbers, since it is widely accepted that there is poor correlation between E. coli and viral and parasite pathogens. Our findings also stress the importance of the external environment, typically wildlife, as sources of faecal contamination
Communication, digital media and future: new scenarios and future changes
Proceedings of the MEDCOM 2020+1 International Conferenc
Design considerations for a new generation of SiPMs with unprecedented timing resolution
The potential of photon detectors to achieve precise timing information is of
increasing importance in many domains, PET and CT scanners in medical imaging
and particle physics detectors, amongst others. The goal to increase by an
order of magnitude the sensitivity of PET scanners and to deliver, via
time-of-flight (TOF), true space points for each event, as well as the
constraints set by future particle accelerators require a further leap in time
resolution of scintillator-based ionizing radiation detectors, reaching
eventually a few picoseconds resolution for sub MeV energy deposits. In spite
of the impressive progress made in the last decade by several manufacturers,
the Single Photon Time Resolution (SPTR) of SiPMs is still in the range of
70-120ps FWHM, whereas a value of 10ps or even less would be desirable. Such a
step requires a break with traditional methods and the development of novel
technologies. The possibility of combining the extraordinary potential of
nanophotonics with new approaches offered by modern microelectronics and 3D
electronic integration opens novel perspectives for the development of a new
generation of metamaterial-based SiPMs with unprecedented photodetection
efficiency and timing resolution.Comment: 16 pages, 6 figures, submitted to JINS
Can Homes Affect Well-Being? A Scoping Review among Housing Conditions, Indoor Environmental Quality, and Mental Health Outcomes
The purpose of the scoping review is to explore the relationship between housing conditions, indoor environmental quality (IEQ), and mental health implications on human well-being. In fact, time spent at home increased due to the recent COVID-19 lockdown period, and social-sanitary emergencies are expected to grow due to the urbanization phenomenon. Thus, the role of the physical environment in which we live, study, and work, has become of crucial importance, as the literature has recently highlighted. This scoping review, conducted on the electronic database Scopus, led to the identification of 366 articles. This, after the screening processes based on the inclusion criteria, led to the final inclusion of 31 papers related specifically to the OECD area. The review allowed the identification of five housing conditions [house type, age, and floor level; housing qualities; household composition; neighborhood; green spaces] that, by influencing the IEQ parameters, had impacts on the mental health outcomes addressed. By synthesizing the contributions of the review, a list of design recommendations has been provided. These will serve as a basis for future researchers, from which to develop measures to reduce inequalities in housing by making them healthier, more resilient, and salutogenic
FAST FRONT-END ELECTRONICS FOR EXPERIMENTS USING SILICON CALORIMETERS AT SSC /LHC COLLIDERS
Abstract A fast VLSI preamplifier using HF2CMOS technology was designed and built. The preamplifier meets the requirements for silicon calorimetry application in experiments at hadron colliders SSC/LHC. The overall power consumption is less than 45 mW for a maximum output voltage swing of 5 V (â 7 ns rise time). The slew rate is about 700 V/ÎŒs for an input capacitance of 150 pF. The measured value of ENC (equivalent noise charge), for an RC-CR shaping time of 20 ns and an input capacitance of 150 pF, is 17 ke RMS
SiPM and front-end electronics development for Cherenkov light detection
The Italian Institute of Nuclear Physics (INFN) is involved in the
development of a demonstrator for a SiPM-based camera for the Cherenkov
Telescope Array (CTA) experiment, with a pixel size of 66 mm. The
camera houses about two thousands electronics channels and is both light and
compact. In this framework, a R&D program for the development of SiPMs suitable
for Cherenkov light detection (so called NUV SiPMs) is ongoing. Different
photosensors have been produced at Fondazione Bruno Kessler (FBK), with
different micro-cell dimensions and fill factors, in different geometrical
arrangements. At the same time, INFN is developing front-end electronics based
on the waveform sampling technique optimized for the new NUV SiPM. Measurements
on 11 mm, 33 mm, and 66 mm NUV SiPMs
coupled to the front-end electronics are presentedComment: In Proceedings of the 34th International Cosmic Ray Conference
(ICRC2015), The Hague, The Netherlands. All CTA contributions at
arXiv:1508.0589
Recommended from our members
A simple method for estimating in vitro air-tissue and in vivo blood-tissue partition coefficients
YesA simple method is reported for the estimation of in vivo air-tissue partition coefficients of VOCs and of in vitro blood-tissue partition coefficients for volatile organic compounds and other compounds. Linear free energy relationships for tissues such as brain, muscle, liver, lung, kidney, heart, skin and fat are available and once the Abraham descriptors are known for a compound, no more than simple arithmetic is required to estimate air-tissue and blood-tissue partitions
The prediction of bloodâtissue partitions, waterâskin partitions and skin permeation for agrochemicals
YesBACKGROUND: There is considerable interest in the bloodâtissue distribution of agrochemicals, and a number of researchershave developed experimental methods for in vitro distribution. These methods involve the determination of salineâblood andsalineâtissue partitions; not only are they indirect, but they do not yield the required in vivo distribution.RESULTS: The authors set out equations for gasâtissue and bloodâtissue distribution, for partition from water into skin andfor permeation from water through human skin. Together with Abraham descriptors for the agrochemicals, these equationscan be used to predict values for all of these processes. The present predictions compare favourably with experimental in vivobloodâtissue distribution where available. The predictions require no more than simple arithmetic.CONCLUSIONS: The present method represents a much easier and much more economic way of estimating bloodâtissuepartitions than the method that uses salineâblood and salineâtissue partitions. It has the added advantages of yielding therequired in vivo partitions and being easily extended to the prediction of partition of agrochemicals from water into skin andpermeation from water through skin
Scratching Cu|Au nanolaminates
We used molecular dynamics simulations to study the scratching of CujAu nanolaminates of 5 nm layer thickness with a nanoscale indenter of 15 nm radius at normal forces between 0.5 ”N and 2 ”N. Our simulations show that Au layers wear quickly while Cu layers are more resistant to wear. Plowing was accompanied by the roughening of the Cu|Au heterointerface that lead to the folding of the nanolaminate structure at the edge of the wear track. Our explorative simulations hint at the complex deformation processes occurring in nanolaminates under tribological load
NUV-HD SiPMs with metal-filled trenches
In this paper we present the performance of a new SiPM that is sensitive to blue light and features narrow metal-filled trenches placed in the area around the single-photon avalanche diodes (SPADs) that allow an almost complete suppression the internal optical crosstalk. In particular, we show the benefits of this technological upgrade in terms of electro-optical SiPM performance when compared to the previous technology which had only a partial optical screening between the SPADs. The most relevant effect is the much higher bias voltage that can be applied to the new device before the noise diverges. This allows to optimize and improve both the photon detection efficiency and the single-photon time resolution. We also coupled the SiPMs to LYSO scintillators to verify the performance for possible application in Positron-Emission Tomography. Thanks to the better electro-optical features we were able to measure an improved coincidence time resolution. Furthermore, the optimal voltage operation region is substantially larger, making this SiPM more suitable for real system application where thousands of channels have to provide stable and reproducible performance
- âŠ