Responses of marine benthic microalgae to elevated CO<inf>2</inf>

Increasing anthropogenic CO2 emissions to the atmosphere are causing a rise in pCO2 concentrations in the ocean surface and lowering pH. To predict the effects of these changes, we need to improve our understanding of the responses of marine primary producers since these drive biogeochemical cycles and profoundly affect the structure and function of benthic habitats. The effects of increasing CO2 levels on the colonisation of artificial substrata by microalgal assemblages (periphyton) were examined across a CO2 gradient off the volcanic island of Vulcano (NE Sicily). We show that periphyton communities altered significantly as CO2 concentrations increased. CO2 enrichment caused significant increases in chlorophyll a concentrations and in diatom abundance although we did not detect any changes in cyanobacteria. SEM analysis revealed major shifts in diatom assemblage composition as CO2 levels increased. The responses of benthic microalgae to rising anthropogenic CO2 emissions are likely to have significant ecological ramifications for coastal systems. © 2011 Springer-Verlag

A Quantitative Study of the Mechanisms behind Thymic Atrophy in Gαi2-Deficient Mice during Colitis Development

Mice deficient for the G protein subunit Gαi2 spontaneously develop colitis, a chronic inflammatory disease associated with dysregulated T cell responses. We and others have previously demonstrated a thymic involution in these mice and an aberrant thymocyte dynamics. The Gαi2−/− mice have a dramatically reduced fraction of double positive thymocytes and an increased fraction of single positive (SP) thymocytes. In this study, we quantify a number of critical parameters in order to narrow down the underlying mechanisms that cause the dynamical changes of the thymocyte development in the Gαi2−/− mice. Our data suggest that the increased fraction of SP thymocytes results only from a decreased number of DP thymocytes, since the number of SP thymocytes in the Gαi2−/− mice is comparable to the control littermates. By measuring the frequency of T cell receptor excision circles (TRECs) in the thymocytes, we demonstrate that the number of cell divisions the Gαi2−/− SP thymocytes undergo is comparable to SP thymocytes from control littermates. In addition, our data show that the mature SP CD4+ and CD8+ thymocytes divide to the same extent before they egress from the thymus. By estimating the number of peripheral TREC+ T lymphocytes and their death rate, we could calculate the daily egression of thymocytes. Gαi2−/− mice with no/mild and moderate colitis were found to have a slower export rate in comparison to the control littermates. The quantitative measurements in this study suggest a number of dynamical changes in the thymocyte development during the progression of colitis

The Spatial and Temporal Construction of Confidence in the Visual Scene

Human subjects can report many items of a cluttered field a few hundred milliseconds after stimulus presentation. This memory decays rapidly and after a second only 3 or 4 items can be stored in working memory. Here we compared the dynamics of objective performance with a measure of subjective report and we observed that 1) Objective performance beyond explicit subjective reports (blindsight) was significantly more pronounced within a short temporal interval and within specific locations of the visual field which were robust across sessions 2) High confidence errors (false beliefs) were largely confined to a small spatial window neighboring the cue. The size of this window did not change in time 3) Subjective confidence showed a moderate but consistent decrease with time, independent of all other experimental factors. Our study allowed us to asses quantitatively the temporal and spatial access to an objective response and to subjective reports

Phase I/II study of S-1 combined with irinotecan for metastatic advanced gastric cancer

A dose-escalation study of irinotecan (CPT-11) combined with S-1, an oral dihydropyrimidine dehydrogenase inhibitory fluoropyrimidine, was performed to determine the maximum-tolerated dose (MTD), recommended dose (RD), dose-limiting toxicities (DLTs), and objective response rate (RR) in advanced gastric cancer (AGC). S-1 was administered orally at 80 mg m−2 day−1 from day 1 to 14 of a 28-day cycle and CPT-11 was given intravenously on day 1 and 8 at an initial dose of 70 mg m−2 day−1, stepping up to 100 mg m−2. The treatment was repeated every 4 weeks, unless disease progression was observed. In the phase I portion, the MTD of CPT-11 was presumed to be 100 mg m−2, because 66.6% of patients (two of three) developed DLTs. All three patients at the initial RD of CPT-11 (90 mg m−2) experienced grade 4 haematological or grade 3 nonhaematological toxicities at second course, followed by the dose reduction of CPT-11 from the third course. Considering safety and the ability to continue treatment, the final RD was determined to be 80 mg m−2. In the phase II portion, 42 patients including seven patients in the final RD phase I portion were evaluated. The median treatment course was five (range: 1–13). The incidences of severe (grade 3–4) haematological and nonhaematological toxicities were 19 and 10%, respectively, but all were manageable. The RR was 62% (26 of 42, 95% confidence interval: 47.2–76.6%), and the median survival time was 444 days. Our phase I/II trial showed S-1 combined with CPT-11 is effective for AGC and is well tolerated, with acceptable toxicity

Phase II study of capecitabine and cisplatin as first-line combination therapy in patients with gastric cancer recurrent after fluoropyrimidine-based adjuvant chemotherapy

To evaluate the efficacy and safety of capecitabine and cisplatin in patients with recurrent gastric cancer after fluoropyrimidine-based adjuvant therapy. Patients with histologically confirmed and measurable advanced gastric cancer that had relapsed after fluoropyrimidine-based adjuvant chemotherapy received oral capecitabine (1250 mg m−2 twice daily, days 1–14) and intravenous cisplatin (60 mg m−2 over 1 h, day 1) every 3 weeks. In total, 32 patients were enrolled, of whom 30 were evaluable for efficacy and 32 for safety. A median of 5 cycles (range 1–10) was administered. One patient achieved a complete response and eight had partial responses, giving an overall response rate of 28% (95% CI, 13–44%). The median time to progression and median overall survival were 5.8 months (95% CI, 4.1–7.5 months) and 11.2 months (95% CI, 5.5–16.9 months), respectively. Grade 3 neutropenia and thrombocytopenia were observed in 38 and 6% of patients, respectively. Grade 2/3 nonhaematological toxicities included diarrhoea (19%), stomatitis (19%) and hand-foot syndrome (31%). No grade 4 toxicity, neutropenic fever or treatment-related deaths occurred. Capecitabine in combination with cisplatin was effective and well tolerated as first-line treatment in patients with recurrent gastric cancer after fluoropyrimidine-based adjuvant chemotherapy

Search for the standard model Higgs boson in the H to ZZ to 2l 2nu channel in pp collisions at sqrt(s) = 7 TeV

A search for the standard model Higgs boson in the H to ZZ to 2l 2nu decay channel, where l = e or mu, in pp collisions at a center-of-mass energy of 7 TeV is presented. The data were collected at the LHC, with the CMS detector, and correspond to an integrated luminosity of 4.6 inverse femtobarns. No significant excess is observed above the background expectation, and upper limits are set on the Higgs boson production cross section. The presence of the standard model Higgs boson with a mass in the 270-440 GeV range is excluded at 95% confidence level.Comment: Submitted to JHE

Search for anomalous t t-bar production in the highly-boosted all-hadronic final state

A search is presented for a massive particle, generically referred to as a Z', decaying into a t t-bar pair. The search focuses on Z' resonances that are sufficiently massive to produce highly Lorentz-boosted top quarks, which yield collimated decay products that are partially or fully merged into single jets. The analysis uses new methods to analyze jet substructure, providing suppression of the non-top multijet backgrounds. The analysis is based on a data sample of proton-proton collisions at a center-of-mass energy of 7 TeV, corresponding to an integrated luminosity of 5 inverse femtobarns. Upper limits in the range of 1 pb are set on the product of the production cross section and branching fraction for a topcolor Z' modeled for several widths, as well as for a Randall--Sundrum Kaluza--Klein gluon. In addition, the results constrain any enhancement in t t-bar production beyond expectations of the standard model for t t-bar invariant masses larger than 1 TeV.Comment: Submitted to the Journal of High Energy Physics; this version includes a minor typo correction that will be submitted as an erratu

Search for New Physics with Jets and Missing Transverse Momentum in pp collisions at sqrt(s) = 7 TeV

A search for new physics is presented based on an event signature of at least three jets accompanied by large missing transverse momentum, using a data sample corresponding to an integrated luminosity of 36 inverse picobarns collected in proton--proton collisions at sqrt(s)=7 TeV with the CMS detector at the LHC. No excess of events is observed above the expected standard model backgrounds, which are all estimated from the data. Exclusion limits are presented for the constrained minimal supersymmetric extension of the standard model. Cross section limits are also presented using simplified models with new particles decaying to an undetected particle and one or two jets

Measurement of the Z/gamma* + b-jet cross section in pp collisions at 7 TeV

The production of b jets in association with a Z/gamma* boson is studied using proton-proton collisions delivered by the LHC at a centre-of-mass energy of 7 TeV and recorded by the CMS detector. The inclusive cross section for Z/gamma* + b-jet production is measured in a sample corresponding to an integrated luminosity of 2.2 inverse femtobarns. The Z/gamma* + b-jet cross section with Z/gamma* to ll (where ll = ee or mu mu) for events with the invariant mass 60 < M(ll) < 120 GeV, at least one b jet at the hadron level with pT > 25 GeV and abs(eta) < 2.1, and a separation between the leptons and the jets of Delta R > 0.5 is found to be 5.84 +/- 0.08 (stat.) +/- 0.72 (syst.) +(0.25)/-(0.55) (theory) pb. The kinematic properties of the events are also studied and found to be in agreement with the predictions made by the MadGraph event generator with the parton shower and the hadronisation performed by PYTHIA.Comment: Submitted to the Journal of High Energy Physic

Combined search for the quarks of a sequential fourth generation

Results are presented from a search for a fourth generation of quarks produced singly or in pairs in a data set corresponding to an integrated luminosity of 5 inverse femtobarns recorded by the CMS experiment at the LHC in 2011. A novel strategy has been developed for a combined search for quarks of the up and down type in decay channels with at least one isolated muon or electron. Limits on the mass of the fourth-generation quarks and the relevant Cabibbo-Kobayashi-Maskawa matrix elements are derived in the context of a simple extension of the standard model with a sequential fourth generation of fermions. The existence of mass-degenerate fourth-generation quarks with masses below 685 GeV is excluded at 95% confidence level for minimal off-diagonal mixing between the third- and the fourth-generation quarks. With a mass difference of 25 GeV between the quark masses, the obtained limit on the masses of the fourth-generation quarks shifts by about +/- 20 GeV. These results significantly reduce the allowed parameter space for a fourth generation of fermions.Comment: Replaced with published version. Added journal reference and DO