Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

The inclusive and dijet production cross-sections have been measured for jets containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The measurements use data corresponding to an integrated luminosity of 34 pb^-1. The b-jets are identified using either a lifetime-based method, where secondary decay vertices of b-hadrons in jets are reconstructed using information from the tracking detectors, or a muon-based method where the presence of a muon is used to identify semileptonic decays of b-hadrons inside jets. The inclusive b-jet cross-section is measured as a function of transverse momentum in the range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet cross-section is measured as a function of the dijet invariant mass in the range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets and the angular variable chi in two dijet mass regions. The results are compared with next-to-leading-order QCD predictions. Good agreement is observed between the measured cross-sections and the predictions obtained using POWHEG + Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet cross-section. However, it does not reproduce the measured inclusive cross-section well, particularly for central b-jets with large transverse momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final version published in European Physical Journal

Measurement of charged-particle event shape variables in inclusive root(s)=7 TeV proton-proton interactions with the ATLAS detector

The measurement of charged-particle event shape variables is presented in inclusive inelastic pp collisions at a center-of-mass energy of 7 TeV using the ATLAS detector at the LHC. The observables studied are the transverse thrust, thrust minor, and transverse sphericity, each defined using the final-state charged particles' momentum components perpendicular to the beam direction. Events with at least six charged particles are selected by a minimum-bias trigger. In addition to the differential distributions, the evolution of each event shape variable as a function of the leading charged-particle transverse momentum, charged-particle multiplicity, and summed transverse momentum is presented. Predictions from several Monte Carlo models show significant deviations from data

Measurements of differential cross-sections in top-quark pair events with a high transverse momentum top quark and limits on beyond the Standard Model contributions to top-quark pair production with the ATLAS detector at √s = 13 TeV

Cross-section measurements of top-quark pair production where the hadronically decaying top quark has transverse momentum greater than 355 GeV and the other top quark decays into ℓνb are presented using 139 fb−1 of data collected by the ATLAS experiment during proton-proton collisions at the LHC. The fiducial cross-section at s = 13 TeV is measured to be σ = 1.267 ± 0.005 ± 0.053 pb, where the uncertainties reflect the limited number of data events and the systematic uncertainties, giving a total uncertainty of 4.2%. The cross-section is measured differentially as a function of variables characterising the tt¯ system and additional radiation in the events. The results are compared with various Monte Carlo generators, including comparisons where the generators are reweighted to match a parton-level calculation at next-to-next-to-leading order. The reweighting improves the agreement between data and theory. The measured distribution of the top-quark transverse momentum is used to search for new physics in the context of the effective field theory framework. No significant deviation from the Standard Model is observed and limits are set on the Wilson coefficients of the dimension-six operators OtG and Otq(8), where the limits on the latter are the most stringent to date. [Figure not available: see fulltext.]

Observation of electroweak production of two jets in association with an isolated photon and missing transverse momentum, and search for a Higgs boson decaying into invisible particles at 13 TeV with the ATLAS detector

This paper presents the measurement of the electroweak production of two jets in association with a $Z\gamma$ pair with the $Z$ boson decaying into two neutrinos. It also presents the search for invisible or partially invisible decays of a Higgs boson with a mass of 125 GeV produced through vector-boson fusion with a photon in the final state. These results use data from LHC proton-proton collisions at $\sqrt{s}$ = 13 TeV collected with the ATLAS detector corresponding to an integrated luminosity of 139 fb$^{-1}$. The event signature, shared by all benchmark processes considered for measurements and searches, is characterized by a significant amount of unbalanced transverse momentum and a photon in the final state, in addition to a pair of forward jets. For electroweak production of $Z\gamma$ in association with two jets, the background-only hypothesis is rejected with an observed (expected) significance of 5.2 (5.1) standard deviations. The measured fiducial cross-section for this process is 1.31$\pm$0.29 fb. Observed (expected) upper limit of 0.37 (0.34) at 95% confidence level is set on the branching ratio of a 125 GeV Higgs boson to invisible particles, assuming the Standard Model production cross-section. The signature is also interpreted in the context of decays of a Higgs boson to a photon and a dark photon. An observed (expected) 95% CL upper limit on the branching ratio for this decay is set at 0.018 (0.017), assuming the 125 GeV Standard Model Higgs boson production cross-section

Key role of proline L209 in connecting the distant quinone pockets in the reaction center of Rhodobacter sphaeroides

Photosynthetic bacterial reaction centers convert light excitation into chemical free energy. The initial electron transfer leads to the consecutive semireductions of the primary (Q(A)) and secondary (Q(B)) quinone acceptors. The Q [Formula: see text] and Q [Formula: see text] formations induce proton uptake from the bulk. Their magnitudes (H(+)/Q [Formula: see text] and H(+)/Q [Formula: see text] , respectively) probe the electrostatic interactions within the complex. The pH dependence of H(+)/Q [Formula: see text] and H(+)/Q [Formula: see text] were studied in five single mutants modified at the L209 site (L209P→F,Y,W,E,T). This residue is situated at the border of a continuous chain of water molecules connecting Q(B) to the bulk. In the wild type (WT), a proton uptake band is present at high pH in the H(+)/Q [Formula: see text] and H(+)/Q [Formula: see text] curves and is commonly attributed to a cluster of acidic groups situated nearby Q(B). In the H(+)/Q [Formula: see text] curves of the L209 variants, this band is systematically absent but remains in the H(+)/Q [Formula: see text] curves. Moreover, notable increase of H(+)/Q [Formula: see text] is observed in the L209 mutants at neutral pH as compared with the WT. The large effects observed in all L209 mutants are not associated with significant structural changes (Kuglstatter, A., Ermler, U., Michel, H., Baciou, L. & Fritzsch, G. Biochemistry (2001) 40, 4253–4260). Our data suggest that, in the L209 mutants, the Q(B) cluster does not respond to the Q [Formula: see text] formation as observed in the WT. We propose that, in the mutants, removal of the rigid proline L209 breaks a necessary hydrogen bonding connection between the quinone sites. These findings suggest an important role for structural rigidity in ensuring a functional interaction between quinone binding sites

Nuorten päihteiden käyttö ja vanhempien saama tuki

Nuorten päihteiden käyttö on lisääntynyt viime vuosina. Nuoret eivät yleensä ole päihteistä riippuvaisia, mutta satunnainenkin kokeilu ja käyttö ovat haitallisia. Päihteiden käyttö voi olla yksittäinen ongelma, mutta myös osa suurempaa ongelmakokonaisuutta. Tämän vuoksi nuoren tilannetta tulee tarkastella kokonaisvaltaisesti. Päihteiden käyttöä ei aina huomata, ja sen ilmeneminen voi olla sokki läheisille. Päihteiden käyttö on ongelma käyttäjälle, mutta voi sairastuttaa myös läheiset. Läheiset, usein nuorten vanhemmat, tarvitsevat myös tukea ja neuvoa tilanteessa. Vanhempien oma asenne ja päihdekäyttäytyminen sekä nuoren asioista perillä oleminen ovat tärkeitä ehkäiseviä tekijöitä nuoren päihteiden käytölle. Myös nuoren oma asenne päihteisiin sekä sosiaaliset suhteet ja onnistumisen kokemukset ovat päihteiltä suojaavia tekijöitä. Tämä opinnäytetyö on tehty kokoamalla kattavasti teoriatietoa päihteistä, niiden käytöstä ja haitoista. Etelä-Karjalan sosiaali- ja terveyspiirin (Eksoten) internet-sivuilta selvitettiin, mistä ja miten voi hakea apua ja neuvoja läheisen päihteiden käytön ongelmiin. Lisäksi tehtiin kysely päihdenuorten vanhemmille. Kyselyllä selvitettiin päihdenuorten vanhempien omaa kokemusta saamastaan tuesta sosiaali- ja terveysalan ammattilaisilta. Tulokset analysoitiin empiirisesti. Tulosten mukaan osa vanhemmista on tyyty-väisiä saamaansa tukeen, osa taas kokee, ettei ole saanut tarpeeksi tukea ja tietoa. Päihdepalvelujen parempi ja määrällisesti laajempi saatavuus on kyse-lyyn vastanneiden vanhempien toiveissa. Tästä voidaan päätellä, että päih-denuorten vanhemmat otetaan huomioon ja tukea on tarjolla, mutta kaikkia tuki ei tavoita. Jatkotutkimuksessa voisi selvittää millaiseksi päihdenuoret kokevat saamansa hoidon. Lisäksi voisi selvittää miten sosiaali- ja terveysalan ammattilaiset koke-vat voivansa vaikuttaa nuorten päihdekäyttäytymiseen ja miten sosiaali- ja ter-veysalan ammattilaiset voisivat ottaa päihdenuorten vanhemmat paremmin huomioon. Kirjallisen nuorten päihdeasioita käsittelevän oppaan tekeminen ja jakaminen vanhemmille voisi olla hyödyllinen.Intoxicant use and abuse in young people has increased in recent years. Young people are generally not dependent on intoxicants, but occasional experimentation and use are harmful. Intoxicant use can be a single problem or part of a larger set of problems. Because of this, the situation of the young people should be considered from a broad perspective. Intoxicant use is not always noticed and its appearance may be a shock to those close to the user. Intoxicant use is a problem in the user, but can cause problems for families and friends, as well. Closely related, commonly parents, also need support and counsel in these situations. Parent's own attitudes and customs to use intoxicants, and knowing well issues about young people are important preventive factors for young people's intoxicant use. Also young people's attitude to intoxicant use and social affairs and experience of success are protective factors for intoxicant use. This thesis has been done by collecting comprehensive information on theory of intoxicant consumption and drawbacks of them. With the help of South Karelia District of Social and Health Service's websites, information about where and how to get help and advice for those close to young people with problems was found. In addition to this has been done an inquiry to parents of young people who use intoxicants. By the inquiry, the parents own experiences of having support from professionals in social and health care were examined. The results were analyzed empirically. According to the results, a proportion of parents are satisfied for support they have got, whereas part of parents find that they have not had enough support and information. The parents hope for better and wider availability of services for intoxicant users. Parents of young intoxicant abusers were taken into ac-count, and support services are available, but they do not reach all who need them. For further study, the opinions of the young people, and also of the health professionals about care of intoxicant abusers would be of interest