1,887 research outputs found
Rapidity distributions of strange particles in Pb-Pb at 158 A GeV/c
The production at central rapidity of K0s, Lambda, Xi and Omega particles in
Pb-Pb collisions at 158 A GeV/c has been measured by the NA57 experiment over a
centrality range corresponding to the most central 53% of the inelastic Pb-Pb
cross section. We present the rapidity distribution of each particle in the
central rapidity unit. The distributions are analysed based on hydrodynamical
models of the collisions.Comment: Contribution to the Poster Proceedings of the Quark Matter 2005
Conference. To be published in Nukleonika, International Journal of Nuclear
Researc
Latest results from the NA57 experiment
The NA57 experiment at the CERN SPS has measured the production of strange
and multi-strange particles in Pb-Pb (and p-Be) collisions at mid-rapidity. The
collective dynamics of the collision is studied in the transverse and
longitudinal directions as a function of centrality and beam momentum and
analysed based on hydrodynamical models. Central-to-peripheral nuclear
modification factors at 158 A GeV/c are presented and compared with other
measurements and theory.Comment: Contribution to the Proceedings of QCD@Work 2005 International
Workshop on Quantum Chromodynamics: Theory and Experiment. It should have
gone in the nucl-ex archive
CERN achievements in relativistic heavy ion collisions
Twenty years after a Letter of Intent by the GSI and LBL groups for the “Study of particle production and target fragmentation in central 20Ne on Pb reactions, at 12 GeV per nucleon energy of the CERN PS external beam" [1], based on the results found by the NA45/CERES, NA49, NA50, and WA97/NA57 experiments at the SPS, CERN announced compelling evidence for the formation of a new state of matter in heavyion collisions at CERN-SPS energies [2]. Some of the experiments were indeed the 2nd or 3rd generation successors of the apparatuses originally proposed by the GSI-LBL collaboration. Actually, the CERN ion program initiated at the SPS with the acceleration of oxygen ions at 60 and 200 GeV/nucleon only in 1986, and continued with sulphur ions at 200 GeV/nucleon up to 1993. The rest is history: lead-ion beams at 160 GeV/nucleon became available at the SPS in 1994; the LHC accelerated and collided lead beams at a center of mass energy per nucleon pair √sNN = 2.76 TeV in 2010. Heavy ion physics is definitely in the future program of CERN: ALICE will operate a major upgrade of its detectors during the second long shutdown of the LHC, in 2018-2019, and the associated physics program will span the third and fourth LHC runs, till late 2020s
All Sky Camera, LIDAR and Electric Field Meter: auxiliary instruments for the ASTRI SST-2M prototype
ASTRI SST-2M is the end-to-end prototype telescope of the Italian National
Institute of Astro- physics, INAF, designed to investigate the 10-100 TeV band
in the framework of the Cherenkov Telescope Array, CTA. The ASTRI SST-2M
telescope has been installed in Italy in September 2014, at the INAF ob-
serving station located at Serra La Nave on Mount Etna. The telescope is
foreseen to be completed and fully operative in spring 2015 including auxiliary
instrumentation needed to support both operations and data anal- ysis. In this
contribution we present the current status of a sub-set of the auxiliary
instruments that are being used at the Serra La Nave site, namely an All Sky
Camera, an Electric Field Meter and a Raman Lidar devoted, together with
further instrumentation, to the monitoring of the atmospheric and environmental
conditions. The data analysis techniques under development for these
instruments could be applied at the CTA sites, where similar auxiliary
instrumentation will be installed.Comment: Proceedings of the 2nd AtmoHEAD Conference, Padova (Italy) May 19-21,
201
Gallus gallus NEU3 sialidase as model to study protein evolution mechanism based on rapid evolving loops
<p>Abstract</p> <p>Background</p> <p>Large surface loops contained within compact protein structures and not involved in catalytic process have been proposed as preferred regions for protein family evolution. These loops are subjected to lower sequence constraints and can evolve rapidly in novel structural variants. A good model to study this hypothesis is represented by sialidase enzymes. Indeed, the structure of sialidases is a β-propeller composed by anti-parallel β-sheets connected by loops that suit well with the rapid evolving loop hypothesis. These features prompted us to extend our studies on this protein family in birds, to get insights on the evolution of this class of glycohydrolases.</p> <p>Results</p> <p><it>Gallus gallus (Gg) </it>genome contains one <it>NEU3 </it>gene encoding a protein with a unique 188 amino acid sequence mainly constituted by a peptide motif repeated six times in tandem with no homology with any other known protein sequence. The repeat region is located at the same position as the roughly 80 amino acid loop characteristic of mammalian NEU4. Based on molecular modeling, all these sequences represent a connecting loop between the first two highly conserved β-strands of the fifth blade of the sialidase β-propeller. Moreover this loop is highly variable in sequence and size in NEU3 sialidases from other vertebrates. Finally, we found that the general enzymatic properties and subcellular localization of Gg NEU3 are not influenced by the deletion of the repeat sequence.</p> <p>Conclusion</p> <p>In this study we demonstrated that sialidase protein structure contains a surface loop, highly variable both in sequence and size, connecting two conserved β-sheets and emerging on the opposite site of the catalytic crevice. These data confirm that sialidase family can serve as suitable model for the study of the evolutionary process based on rapid evolving loops, which may had occurred in sialidases. Giving the peculiar organization of the loop region identified in Gg NEU3, this protein can be considered of particular interest in such evolutionary studies and to get deeper insights in sialidase evolution.</p
Prevention of Harmful Algal Bloom
近年来在沿海以及河口等地区有害赤潮频频暴发。由于赤潮暴发会导致水体藻类大量增殖和有害毒素的产生,这严重破坏了水生生态系统,并且影响了地区经济,周边居民的健康以及休闲娱乐活动。因此,控制和预防沿海赤潮暴发迫在眉睫。 本研究重点论述在河口区域如何有效预防HABs(单细胞微生物的迅速增长导致危害)以及所带来的负面效应。建立有效的预防措施,我们首先必须充分理解引起HABs的各种原因。针对沿海河口特殊的地理环境,污染物来源比较复杂,工业废水、城市生活污水、农业养殖业废水和大气沉降水等都成为HABs的主要根源。本文根据这些原因阐述相应的有效预防措施。 首先政府应该根据清洁水法案的规定和标准来严格控制工...In the last few decades an excessive increase of harmful algal blooms (HABs) the rapid increase of microscopic single-celled organisms that cause harmful effect occurred in coastal areas and in estuaries as well. Due to production of high biomass and toxins, the occurrence of HABs leads to deterioration of aquatic ecosystems and negative effects on economy, people health and recreation activities....学位:工学硕士院系专业:海洋与环境学院海洋学系_海洋事务学号:2242008115368
Diabetes does not impact the diagnostic performance of contrast-based fractional flow reserve: insights from the CONTRAST study
Background: Adenosine-free coronary pressure wire metrics have been proposed to test the functional significance
of coronary artery lesions, but it is unexplored whether their diagnostic performance might be altered in patients with
diabetes.
Methods: We performed a post-hoc analysis of the CONTRAST study, which prospectively enrolled an international
cohort of patients undergoing routine fractional flow reserve (FFR) assessment for standard indications. Paired,
repeated measurements of all physiology metrics (Pd/Pa, iFR, contrast-based FFR, and FFR) were made. A central core
laboratory analyzed blinded pressure tracings in a standardized fashion.
Results: Of 763 subjects enrolled at 12 international centers, 219 (29%) had diabetes. The two groups were wellbalanced
for age, clinical presentation (stable or unstable), coronary vessel studied, volume and type of intracoronary
contrast, and volume of intracoronary adenosine. A binary threshold of cFFR ≤ 0.83 produced an accuracy superior
to both Pd/Pa and iFR when compared with FFR ≤ 0.80 in the absence of significant interaction with diabetes status;
indeed, accuracy in subgroups of patients with or without diabetes was similar for cFFR (86.7 vs 85.4% respectively;
p = 0.76), iFR (84.2 vs 80.0%, p = 0.29) and Pd/Pa (81.3 vs 78.9%, p = 0.55). There was no significant heterogeneity
between patients with or without diabetes in terms of sensitivity and specificity of all metrics. The area under
the receiver operating characteristic (ROC) curve was largest for cFFR compared with Pd/Pa and iFR which were
equivalent (cFFR 0.961 and 0.928; Pd/Pa 0.916 and 0.870; iFR 0.911 and 0.861 in diabetic and non-diabetic patients
respectively).
Conclusions: cFFR provides superior diagnostic performance compared with Pd/Pa or iFR for predicting FFR irrespective
of diabetes (clinicaltrials.gov identifier NCT02184117)
Breast conserving treatment for ductal carcinoma in situ in the elderly: Can radiation therapy be avoided? Our experience
AbstractIntroduction: Ductal Carcinoma In Situ (DCIS) is a heterogeneous, pre-malignant disease accounting for 15–20% of all new breast cancers. If appropriately managed, DCIS has a small chance of impacting on patient life expectancy. Despite the possibility of a further recurrence or of a development in an invasive form, we are unable to select treatment of choice especially in the elderly. In particularly we risk an overtreatment of women at low risk of progression to invasive breast cancer. The aim of this study was to retrospectively evaluate the outcome of elderly patients affected by DCIS not undergoing Radiation Therapy (RT) after Breast Conserving Surgery (BCS). Material and methods: We reviewed our prospectively-maintained database from 1998 to 2013, selecting all women over 65 years old diagnosed with DCIS who did not receive RT for personal choice. We considered two groups, according to the risk of local recurrence (Low Risk (Group 1) vs. High Risk (Group 2)). Results: We identified 44 cases of DCIS treated with surgery alone or with surgery followed by adjuvant tamoxifen. 24 patients presented low risk of local recurrence (Group 1) and 20 had characteristics associated to high risk of local recurrence (Group 2). At a median follow-up of 66.3 months, no local recurrences have been described in group 1. No patients presented distant metastases, while 4 patients died for other causes. At a median follow-up of 72 months we observed 5 local recurrences in the second group (p < 0.05). Conclusion: Our results suggest that radiation therapy can be safely avoided in a selected group of elderly patients affected by DCIS
New-onset atrial fibrillation and increased mortality after transcatheter aortic valve implantation: A causal or spurious association?
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