Measurement of charm production at central rapidity in proton-proton collisions at s=2.76\sqrt{s} = 2.76 TeV

The $p_{\rm T}$-differential production cross sections of the prompt (B feed-down subtracted) charmed mesons D$^0$, D$^+$, and D$^{*+}$ in the rapidity range $|y|<0.5$, and for transverse momentum $1< p_{\rm T} <12$ GeV/$c$, were measured in proton-proton collisions at $\sqrt{s} = 2.76$ TeV with the ALICE detector at the Large Hadron Collider. The analysis exploited the hadronic decays D$^0 \rightarrow$K$\pi$, D$^+ \rightarrow$K$\pi\pi$, D$^{*+} \rightarrow$D$^0\pi$, and their charge conjugates, and was performed on a $L_{\rm int} = 1.1$ nb$^{-1}$ event sample collected in 2011 with a minimum-bias trigger. The total charm production cross section at $\sqrt{s} = 2.76$ TeV and at 7 TeV was evaluated by extrapolating to the full phase space the $p_{\rm T}$-differential production cross sections at $\sqrt{s} = 2.76$ TeV and our previous measurements at $\sqrt{s} = 7$ TeV. The results were compared to existing measurements and to perturbative-QCD calculations. The fraction of cdbar D mesons produced in a vector state was also determined.Comment: 20 pages, 5 captioned figures, 4 tables, authors from page 15, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/307

Particle-yield modification in jet-like azimuthal di-hadron correlations in Pb-Pb collisions at sNN\sqrt{s_{\rm NN}} = 2.76 TeV

The yield of charged particles associated with high-$p_{\rm T}$ trigger particles ($8 < p_{\rm T} < 15$ GeV/$c$) is measured with the ALICE detector in Pb-Pb collisions at $\sqrt{s_{\rm NN}}$ = 2.76 TeV relative to proton-proton collisions at the same energy. The conditional per-trigger yields are extracted from the narrow jet-like correlation peaks in azimuthal di-hadron correlations. In the 5% most central collisions, we observe that the yield of associated charged particles with transverse momenta $p_{\rm T}> 3$ GeV/$c$ on the away-side drops to about 60% of that observed in pp collisions, while on the near-side a moderate enhancement of 20-30% is found.Comment: 15 pages, 2 captioned figures, 1 table, authors from page 10, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/350

Long-range Angular Correlations On The Near And Away Side In P-pb Collisions At √snn=5.02 Tev

7191/Mar294

Centrality Dependence Of The Pseudorapidity Density Distribution For Charged Particles In Pb-pb Collisions At √snn=2.76tev

7264/Mai61062

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time, and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space. While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes, vast areas of the tropics remain understudied. In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity, but it remains among the least known forests in America and is often underrepresented in biodiversity databases. To worsen this situation, human-induced modifications may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge, it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

Elliptic flow of identified hadrons in Pb-Pb collisions at 1asNN = 2.76 TeV

The elliptic flow coefficient (v2) of identified particles in Pb-Pb collisions at 1asNN = 2.76 TeV was measured with the ALICE detector at the Large Hadron Collider (LHC). The results were obtained with the Scalar Product method, a two-particle corre- lation technique, using a pseudo-rapidity gap of | 06\u3b7| > 0.9 between the identified hadron under study and the reference particles. The v2 is reported for \u3c0\ub1, K\ub1, K0S, p+p, \u3c6, \u39b+\u39b, \u39e 12+\u39e+ and \u3a9 12+\u3a9+ in several collision centralities. In the low transverse momentum (pT) region, pT 3 GeV/c

Biofilm formation by Staphylococcus aureus on food contact surfaces: Relationship with temperature and cell surface hydrophobicity

Staphylococcus aureus (S.aureus) is a pathogenic bacterium capable of developing biofilms on food processing surfaces, a pathway leading to cross contamination of foods. The purpose of this study was to evaluate the ability of S.aureus to form biofilm on food processing surfaces (polystyrene and stainless steel) with regard to different temperatures (12 and 37°C) and cellular hydrophobicity. Biofilm assays were performed on n. 67 S.aureus isolates from food, food processing environments and food handlers and n. 3 reference strains (S.aureus ATCC 35556, S.aureus ATCC 12600 and S.epidermidis ATCC 12228). A strain-specific variation in biofilm formation within S.aureus strains tested was observed. At 37°C, n. 38/67 (56.7%) of strains were biofilm producer in at least one tested surface. A total of n. 25/38 (65.7%) of strains were biofilm producer on polystyrene whereas n. 24/38 (63.1%) were biofilm producer on stainless steel. Moreover, n. 11/38 (28.9%) of strains were biofilm producers on both selected surfaces. The majority of S.aureus strains which produced biofilms (n. 17/38-44.7%), were isolated from food environments. At 12°C, only one S.aureus strain from food handler (S.aureus 374) was biofilm producer. Cell surface hydrophobicity level increased with temperature. Additionally, a statistically significant difference (P<0.001) was found between hydrophobicity at 37°C and 12°C. Finally, the architecture of biofilm formed by S.aureus strains on polystyrene and stainless steel surfaces at selected temperatures was observed by scanning electron microscopy. The appearance of thick extracellular products in strongly (S.aureus ATCC 35556 - positive control) and the absence of those products in the non-biofilm producer (S.epidermidis ATCC 12228 - negative control) is presented

Sources and tracking of Listeria monocytogenes in a cold-smoked processing plant

The compliance of RTE foods with the safety criteria for L. monocytogenes in a cold-smoked salmon processing facility, as laid down in the Commission Regulation 2073/2005, was evaluated. The origin of L. monocytogenes was evaluated in the plant by tracing the bacterium along the production line by using the PFGE. The pathogen was isolated from in the raw materials, but none of the batches of semi-processed product was found positive. On the contrary, the pathogen was isolated from all the tested batches in the final product. The number of fish samples positive for L. monocytogenes clearly increased at the end of the manufacturing stage. The results of the enumeration of L. monocytogenes in the final product (0 days of storage), at 30 days of storage and at the end of the shelf-life, show that, none of the finished products were contaminated by the bacterium. Moreover, samples obtained from the environment revealed that the processing line was contaminated with the bacterium. PFGE with AscI and ApaI yielded respectively two and three restriction patterns. The same pulsotypes were isolated both from the fish and from the environment, suggesting that cross contamination occurred. An important factor in foodborne listeriosis is that the pathogen can grow to significant numbers at refrigeration temperatures when given sufficient time. The presence of L. monocytogenes in RTE foods is now regulated within the EU, which provides that L. monocytogenes should be legally below 100 cfu g−1 during the shelf life of such products (Regulation 2073/2005). The findings from this study indicate that there is need of a good control in the manufacture and retail of pre-packaged cold-smoked salmon as not all the samples examined complied with the legal food safety criteria for L. monocytogenes. Moreover, strict attention must be paid to cleaning and disinfection to control the level of L. monocytogenes and to avoid in-plant colonization by this pathogen