6,194 research outputs found
The abandoned antimony-mines of SE Sardinia: impact on surface waters
This study investigates the impact of abandoned Sb-mines on the Flumendosa River, which is the most important
water resource in southern Sardinia. Hydrogeochemical surveys carried out in 2005 and 2006 indicated a
significant impact of waters flowing out from adits, slag, tailings and waste materials on surface waters. The
contaminated waters show alkaline pH, and high dissolved SO4, Sb and As (up to 1900, 9.6 and 3.5 mg/L,
respectively). Although the flow rates of drainages from the mining area are usually low (in the range of < 0.1 to
1 L/s), the contribution to dissolved concentrations of Sb in the streams downstream of mines is high. Sampling
under high flow conditions in the Flumendosa River before the confluence with the contaminated streams
showed Sb concentrations below the limits established by the guidelines of World Health Organization for
drinking water (i.e. 20 g/L), while downstream of the confluence dissolved Sb was 32 g/L. Contamination in
the Flumendosa extended 16 km, and attenuation (15 g/L Sb) was only observed close to the Flumendosa
mouth
Piecewise planar underwater mosaicing
A commonly ignored problem in planar mosaics, yet often present in practice, is the selection of a reference homography reprojection frame where to attach the successive image frames of the mosaic. A bad choice for the reference frame can lead to severe distortions in the mosaic and can degenerate in incorrect configurations after some sequential frame concatenations. This problem is accentuated in uncontrolled underwater acquisition setups as those provided by AUVs or ROVs due to both the noisy trajectory of the acquisition vehicle - with roll and pitch shakes - and to the non-flat nature of the seabed which tends to break the planarity assumption implicit in the mosaic construction. These scenarios can also introduce other undesired effects, such as light variations between successive frames, scattering and attenuation, vignetting, flickering and noise. This paper proposes a novel mosaicing pipeline, also including a strategy to select the best reference homography in planar mosaics from video sequences which minimizes the distortions induced on each image by the mosaic homography itself. Moreover, a new non-linear color correction scheme is incorporated to handle strong color and luminosity variations among the mosaic frames. Experimental evaluation of the proposed method on real, challenging underwater video sequences shows the validity of the approach, providing clear and visually appealing mosaic
Arsenic in mining environments: evidences from Sardinia (Italy)
In Sardinia, the dispersion of arsenic in the environment appears strictly linked with mineralised bodies and
mining activities. Currently, the areas of main concern are the active gold mine at Furtei, and the abandoned Pb-
As mine at Baccu Locci. At Furtei, the main sources of arsenic are enargite, and arsenian pyrite; an ongoing
monitoring program of water quality in the area around the mine documented so far no major changes with
respect to pre-mine conditions, except for the formation of extremely acid, As-rich pit lakes. At Baccu Locci, the
main primary source is arsenopyrite; arsenic dispersion is essentially due to the past unwise practice of
discarding mine tailings into the nearby creek. Arsenic is slowly released from residual arsenopyrite and
temporary secondary mineral traps such as Fe-oxyhydroxides, causing contamination of soils and waters as far
as 10 km downstream of the mine
Chromatin Protamination and Catsper Expression in Spermatozoa Predict Clinical Outcomes after Assisted Reproduction Programs
Abstract Identification of parameters predicting assisted reproductive technologies (ARTs) success is a major goal of research in reproduction. Quality of gametes is essential to achieve good quality embryos and increase the success of ARTs. We evaluated two sperm parameters, chromatin maturity and expression of the sperm specific calcium channel CATSPER, in relation to ART outcomes in 206 couples undergoing ARTs. Chromatin maturity was evaluated by Chromomycin A3 (CMA3) for protamination and Aniline Blue (AB) for histone persistence and CATSPER expression by a flow cytometric method. CMA3 positivity and CATSPER expression significantly predicted the attainment of good quality embryos with an OR of 6.6 and 14.3 respectively, whereas AB staining was correlated with fertilization rate. In the subgroup of couples with women ≤35 years, CATSPER also predicted achievement of clinical pregnancy (OR = 4.4). Including CMA3, CATSPER and other parameters affecting ART outcomes (female age, female factor and number of MII oocytes), a model that resulted able to predict good embryo quality with high accuracy was developed. CMA3 staining and CATSPER expression may be considered two applicable tools to predict ART success and useful for couple counseling. This is the first study demonstrating a role of CATSPER expression in embryo development after ARTs programs
HEP Applications Evaluation of the EDG Testbed and Middleware
Workpackage 8 of the European Datagrid project was formed in January 2001
with representatives from the four LHC experiments, and with experiment
independent people from five of the six main EDG partners. In September 2002
WP8 was strengthened by the addition of effort from BaBar and D0. The original
mandate of WP8 was, following the definition of short- and long-term
requirements, to port experiment software to the EDG middleware and testbed
environment. A major additional activity has been testing the basic
functionality and performance of this environment. This paper reviews
experiences and evaluations in the areas of job submission, data management,
mass storage handling, information systems and monitoring. It also comments on
the problems of remote debugging, the portability of code, and scaling problems
with increasing numbers of jobs, sites and nodes. Reference is made to the
pioneeering work of Atlas and CMS in integrating the use of the EDG Testbed
into their data challenges. A forward look is made to essential software
developments within EDG and to the necessary cooperation between EDG and LCG
for the LCG prototype due in mid 2003.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics
Conference (CHEP03), La Jolla, CA, USA, March 2003, 7 pages. PSN THCT00
International expert consensus on the surgical anatomic classification of radical hysterectomies
Background: The anatomic descriptions and extents of radical hysterectomy often vary across the literature and operative reports worldwide. The same nomenclature is often used to describe varying procedures, and different nomenclature is often used to describe the same procedure despite the availability of guideline and classification systems. This makes it difficult to interpret retrospective surgical reports, analyze surgical databases, understand technique descriptions, and interpret the findings of surgical studies. Objective: In collaboration with international experts in gynecologic oncology, the purpose of this study was to establish a consensus in defining and interpreting the 2017 updated Querleu-Morrow classification of radical hysterectomies. Study design: The anatomic templates of type A, B, and C radical hysterectomy were documented through a set of 13 images taken at the time of cadaver dissection. An online survey related to radical hysterectomy nomenclature and definitions or descriptions of the associated procedures was circulated among international experts in radical hysterectomy. A 3-step modified Delphi method was used to establish consensus. Image legends were amended according to the experts' responses and then redistributed as part of a second round of the survey. Consensus was defined by a yes response to a question concerning a specific image. Anyone who responded no to a question was welcome to comment and provide justification. A final set of images and legends were compiled to anatomically illustrate and define or describe a lateral, ventral, and dorsal excision of the tissues surrounding the cervix. Results: In total, there were 13 questions to review, and 29 experts completed the whole process. Final consensus exceeded 90% for all questions except 1 (86%). Questions with relatively lower consensus rates concerned the definitions of types A and B2 radical hysterectomy, which were the main innovations of the 2017 updated version of the 2008 Querleu-Morrow classification. Questions with the highest consensus rates concerned the definitions of types B1 and C, which are the most frequently performed radical hysterectomies. Conclusion: The 2017 version of the Querleu-Morrow classification proved to be a robust tool for defining and describing the extent of radical hysterectomies with a high level of consensus among international experts in gynecologic oncology. Knowledge and implementation of the exact definitions of hysterectomy radicality are imperative in clinical practice and clinical research
Measurements of Flavour Dependent Fragmentation Functions in Z^0 -> qq(bar) Events
Fragmentation functions for charged particles in Z -> qq(bar) events have
been measured for bottom (b), charm (c) and light (uds) quarks as well as for
all flavours together. The results are based on data recorded between 1990 and
1995 using the OPAL detector at LEP. Event samples with different flavour
compositions were formed using reconstructed D* mesons and secondary vertices.
The \xi_p = ln(1/x_E) distributions and the position of their maxima \xi_max
are also presented separately for uds, c and b quark events. The fragmentation
function for b quarks is significantly softer than for uds quarks.Comment: 29 pages, LaTeX, 5 eps figures (and colour figs) included, submitted
to Eur. Phys. J.
Bose-Einstein Correlations of Three Charged Pions in Hadronic Z^0 Decays
Bose-Einstein Correlations (BEC) of three identical charged pions were
studied in 4 x 10^6 hadronic Z^0 decays recorded with the OPAL detector at LEP.
The genuine three-pion correlations, corrected for the Coulomb effect, were
separated from the known two-pion correlations by a new subtraction procedure.
A significant genuine three-pion BEC enhancement near threshold was observed
having an emitter source radius of r_3 = 0.580 +/- 0.004 (stat.) +/- 0.029
(syst.) fm and a strength of \lambda_3 = 0.504 +/- 0.010 (stat.) +/- 0.041
(syst.). The Coulomb correction was found to increase the \lambda_3 value by
\~9% and to reduce r_3 by ~6%. The measured \lambda_3 corresponds to a value of
0.707 +/- 0.014 (stat.) +/- 0.078 (syst.) when one takes into account the
three-pion sample purity. A relation between the two-pion and the three-pion
source parameters is discussed.Comment: 19 pages, LaTeX, 5 eps figures included, accepted by Eur. Phys. J.
Search for Neutral Higgs Bosons in e+e- Collisions at sqrt(s) ~189GeV
A search for neutral Higgs bosons has been performed with the OPAL detector
at LEP, using approximately 170 pb-1 of e+e- collision data collected at
sqrt(s)~189GeV. Searches have been performed for the Standard Model (SM)
process e+e- to H0Z0 and the MSSM processes e+e- to H0Z0, A0h0. The searches
are sensitive to the b b-bar and tau antitau decay modes of the Higgs bosons,
and also to the MSSM decay mode h0 to A0A0. OPAL search results at lower
centre-of-mass energies have been incorporated in the limits we set, which are
valid at the 95% confidence level. For the SM Higgs boson, we obtain a lower
mass bound of 91.0 GeV. In the MSSM, our limits are mh>74.8GeV and mA>76.5GeV,
assuming tan(beta)>1, that the mixing of the scalar top quarks is either zero
or maximal, and that the soft SUSY-breaking masses are 1 TeV. For the case of
zero scalar top mixing, we exclude values of tan(beta) between 0.72 and 2.19.Comment: 38 pages, 15 figures, submitted Euro. Phys. J.
Design of a modular Autonomous Underwater Vehicle for archaeological investigations
MARTA (MARine Tool for Archaeology) is a modular AUV (Autonomous Underwater Vehicle) designed and developed by the University of Florence in the framework of the ARROWS (ARchaeological RObot systems for the World's Seas) FP7 European project. The ARROWS project challenge is to provide the underwater archaeologists with technological tools for cost affordable campaigns: i.e. ARROWS adapts and develops low cost AUV technologies to significantly reduce the cost of archaeological operations, covering the full extent of an archaeological campaign (underwater mapping, diagnosis and cleaning tasks). The tools and methodologies developed within ARROWS comply with the "Annex" of the 2001 UNESCO Convention for the protection of Underwater Cultural Heritage (UCH). The system effectiveness and MARTA performance will be demonstrated in two scenarios, different as regards the environment and the historical context, the Mediterranean Sea (Egadi Islands) and the Baltic Sea
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