6,641 research outputs found
Custodial SU(2) Violation and the Origin of Fermion Masses
Custodial breaking due to dynamical fermion masses is studied in a
rather general context and it is shown how some well known limiting cases are
correctly described. The type of ``gap equation'' which can systematically lead
to extra negative contributions to the so--called --parameter is
emphasized. Furthermore general model independent features are discussed and it
is shown how electro--weak precision measurements can be sensitive to the
fermion content and/or dynamical features of a given theory.Comment: HD-THEP-92-55, 18 pages and 2 pages of figures appended as Postscript
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Heat flux measurements and modelling in the RFX-mod experiment
The knowledge of edge plasma transport parameters and plasma edge phenomena is a key element in the design of the first wall for a magnetically confined fusion experiment. In RFX-mod heat flux measurement and edge transport modelling have been done to improve the understanding of this aspect. Heat flux deposition profiles have been evaluated from infrared temperature measurements of insertable graphite limiters. They were inserted up to 12 mm into the reversed field pinch plasma of ohmically heated discharges with Ip=â0.6Ă·1.0 MA, ne=â0.5Ă·3·1019 mâ3 (n/nG<â0.7) and total power of about 10Ă·15 MW. Strong asymmetries in heat flux deposition have been measured in poloidal direction at low density between the electron and the ion drift side and smaller ones in toroidal direction when q(a)â 0. The poloidal asymmetry has been associated to the presence of superthermal electrons [1] while the toroidal one has been less clearly identified as due to the small toroidal extension of the limiters. To account for the 2D deposition nature of heat load on the surface of the employed limiters, a simple 3D code has been developed to evaluate heat flux from temperature data. In this way at the deeper limiter insertions a heat flux decay length of about 2 mm and 2.5 mm has been evaluated in electron and ion drift sides. Modelling of the evaluated heat fluxes has been done using the SOLEDGE2D-EIRENE edge code [2]. This fluid code is well suited for the RFX-mod wall limiter configuration because, thanks to the implemented penalization technique, the computational domain can be extended up to the entire first wall. Edge modelling has shown that measured decay lengths are compatible with energy diffusion coefficients in Scrape Off Layer (SOL) smaller than those commonly evaluated at plasma edge; the cause of the reduced diffusion in the SOL will be discussed in the paper
The LCG PI project: using interfaces for physics data analysis
In the context of the LHC computing grid (LCG) project, the applications area develops and maintains that part of the physics applications software and associated infrastructure that is shared among the LHC experiments. The "physicist interface" (PI) project of the LCG application area encompasses the interfaces and tools by which physicists will directly use the software, providing implementations based on agreed standards like the analysis systems subsystem (AIDA) interfaces for data analysis. In collaboration with users from the experiments, work has started with implementing the AIDA interfaces for (binned and unbinned) histogramming, fitting and minimization as well as manipulation of tuples. These implementations have been developed by re-using existing packages either directly or by using a (thin) layer of wrappers. In addition, bindings of these interfaces to the Python interpreted language have been done using the dictionary subsystem of the LCG applications area/SEAL project. The actual status and the future planning of the project will be presented
Screening of Aroma-Producing Performance of Anticlostridial Lacticaseibacillus casei Strains
The cheesemaking industry is increasingly interested in using adjunct cultures with potential aromatic and anticlostridial activities. In this study, 34 Lb. paracasei and 2 Lb. rhamnosus strains were isolated from a semi-hard cheese and characterized for their proteolytic, esterase, and anticlostridial activity. Moreover, the strains were inoculated in a curd-based medium and the volatile compounds in the headspace of samples were evaluated by solid-phase microextractionâGCâMS analysis. Proteolytic activity was present in 30 strains, whereas only one Lb. paracasei strain showed esterase activity. All strains inhibited Cl. sporogenes, Cl. beijerinckii, and Cl. butyricum, and 18 isolates inhibited at least one Cl. tyrobutyricum strain. Principal component analysis and clustering analysis based on the volatilome grouped strains into three groups. One of these groups was characterized by high amounts of acids and esters and clustered with control samples inoculated with commercial starter cultures, suggesting similarity in the aroma profile. Strains belonging to this group with inhibitory effects against Cl. tyrobutyricum might be exploited as autochthonous adjunct cultures for the reduction of late-blowing defects in semi-hard cheeses
Long-term trends of PM10-bound arsenic, cadmium, nickel, and lead across the Veneto region (NE Italy)
Since the mid-90s, the European Community has
adopted increasingly stringent air quality standards.
Consequently, air quality has generally improved across
Europe. However, current EU standards are still breached
in some European hotspots.
The Veneto region (NE Italy) lies in the eastern
part of the Po Valley, a major European hotspot for air
pollution, where EU standards for particulate matter,
nitrogen oxides and ozone are still breached at some
sites.
This study aims to analyse the PM10-bound
arsenic, cadmium, nickel, and lead concentrations over a
10 years-long period (2010-2020) in the Veneto Region
by using data collected by the local environmental
protection agency (ARPAV) in 20 sampling stations
mostly distributed across the plain areas of the region
and categorized as rural (RUR), urban (URB), and
suburban (SUB) background, industrial (IND) and traffic
(TRA) hotspots (Figure 1). The comprehensive dataset
discussed in this study was statistically investigated to
detect the seasonal trends, their relationship with other
air pollutants and meteorological parameters and their
spatial variations at a regional scale. This study
completes previous air quality studies over the Veneto
region for gaseous pollutants and bulk PM10 (Masiol et al.
2017).
Samplings were carried out according to CEN EN
12341:1998 standard on quartz fibre filters and were
continuous for 24 h, starting at midnight. The gravimetric
determination of PM10 mass was measured following
the CEN EN 12341:2014 standard. The elemental analysis
was performed using an ICP-MS (Agilent 7700) after acid
digestion (EN 14902:2005).
The trends were analysed using different
approaches on the monthly-averaged data. The shape of
trends and their seasonal variations were assessed
through the seasonal-trend decomposition time series
procedure based on âLoessâ (STL). The linear trends were
computed by the Mann-Kendall trend test (p < 0.05) and
the Theil-Sen nonparametric estimator of slope (MK-TS).
Since this latter analysis assumes monotonic linear
trends and does not consider the shape of trends, the
presence of possible breakpoints was investigated using
the piecewise regression.
Generally, monthly patterns of all analysed
elements show higher concentrations during winter,
following PM10 concentrations. Some exceptions were
detected and discussed. Results of trend analysis indicate
statistically significant negative (decreasing) or null linear
trends in almost all stations. A few positive (increasing)
but not statistically significant trends were also detected.
Some sites showed rapid decreases occurred in
short periods and linked to peculiar events or local
causes. Among others, several sites across the Venice
area showed significant drops of arsenic concentrations
after the REACH (Registration Evaluation Authorisation
of Chemicals) implementation (Formenton et al., 2021).
Data used in this study are provided by ARPAV (Agenzia
Regionale per la Prevenzione e Protezione Ambientale
del Veneto, https://www.arpa.veneto.it/)
Air quality during uncontrolled fires: a multi-years case of study
Exposure to high level of pollutant as a consequence of uncontrolled fire is a issue that must be managed in the right way in order to protect environment and ensure a
safe habitat for humans, flora and fauna, because is
well know that emissions occurred during those events
could serious contaminate air soil and water, and some pollutant could be hazardous for the human health (Lemieux, 2002). During uncontrolled fires a lot of contaminants may be emitted, but in high concern for the human
health are persistent organic pollutants (POPs) and
PAHs (Coudon et al., 2019, Zhang et al., 2008).
Moreover uncontrolled burning could release polychlorinated biphenyls dioxin-like (PCB dl), that are generated as by-product during industrial combustions. Those pollutants are all of high concern for human health because they have well-known carcinogenic and
mutagenic properties, e.g. is well known that PAHs is the main carcinogenic constituent of ambient aerosol (Zhang et al., 2008, Fent et al., 2018; Ravindra et al., 2008). Moreover, PCDD/PCDF, frequently referred as
dioxin, are recognized as toxic chemical pollutant, with endocrine proprieties and toxic dioxin congener is classified as group1 carcinogen by the international agency for research in cancer (IARC).
The aim of this study is evaluate how uncontrolled
fires can affect air quality by characterizing persistent organic pollutant emitted from some events occurred
from 2015 to 2018 in Veneto region (northern Italy).
This area is one of the most polluted and urbanized areas in Europe (Larsen et al., 2012)and uncontrolled
fire can further enhance this severe situation, leading
air pollution to critical level.
During those accidental events the Environmental Protection Agency of Veneto (ARPAV), in order to monitoring the effect of fires, and ensure public health, collected some air samples using Hi-vol samplers
equipped with quartz fiber filter (QFF) for collecting
âparticulateâ phase compounds and a polyurethane foam plug (PUF) for retaining âgas-phaseâ compounds. Subsequently, polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/PCDF), polychlorinated biphenyls dioxin-like (PCB dl) and
Polycyclic aromatic hydrocarbons (PAHs), were analysed using a High Resolution Gas Chromatography
(HRGC), coupled with High Resolution Mass Spectrometry (HRMS). As expected results show large increase of
PCDD/PCDF, PCB dl and PAHs during and immediately after incidental fires, with differences in pollutant
composition. Itâs noticeable how, in a few time (hours to days) pollutant concentration presented a clear and strong drop, leading air quality to better conditions. This drop is probably due to meteorological factors, that will be investigated
Distributed Computing Grid Experiences in CMS
The CMS experiment is currently developing a computing system capable of serving, processing and archiving the large number of events that will be generated when the CMS detector starts taking data. During 2004 CMS undertook a large scale data challenge to demonstrate the ability of the CMS computing system to cope with a sustained data-taking rate equivalent to 25% of startup rate. Its goals were: to run CMS event reconstruction at CERN for a sustained period at 25 Hz input rate; to distribute the data to several regional centers; and enable data access at those centers for analysis. Grid middleware was utilized to help complete all aspects of the challenge. To continue to provide scalable access from anywhere in the world to the data, CMS is developing a layer of software that uses Grid tools to gain access to data and resources, and that aims to provide physicists with a user friendly interface for submitting their analysis jobs. This paper describes the data challenge experience with Grid infrastructure and the current development of the CMS analysis system
Electromagnetic filaments and edge modifications induced by electrode biasing in the RFX-mod tokamak
Diffractive Dissociation In The Interacting Gluon Model
We have extended the Interacting Gluon Model (IGM) to calculate diffractive
mass spectra generated in hadronic collisions. We show that it is possible to
treat both diffractive and non-diffractive events on the same footing, in terms
of gluon-gluon collisions. A systematic analysis of available data is
performed. The energy dependence of diffractive mass spectra is addressed. They
show a moderate narrowing at increasing energies. Predictions for LHC energies
are presented.Comment: 12 pages, latex, 14 figures (PostScript Files included); accepted for
publication in Phys. Rev. D (Feb.97
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