QCD and total cross-sections : photons and hadrons

In this contribution, we discuss a total cross-section model which can be applied to both photon and purely hadronic processes. We find that the model can reproduce photo-production cross-sections, as well as extrapolation of gamma*p processes to gamma p using Vector Meson Dominance models, with minimal modifications from the proton case.

QCD and total cross-sections : photons and hadrons

In this contribution, we discuss a total cross-section model which can be applied to both photon and purely hadronic processes. We find that the model can reproduce photo-production cross-sections, as well as extrapolation of gamma*p processes to gamma p using Vector Meson Dominance models, with minimal modifications from the proton case.

Vibrational phase relaxation of O–H stretch in bulk water: Role of large amplitude angular jumps and negative cross-correlations among the forces on the O–H bond

The ultrafast vibrational phase relaxation of O–H stretch in bulk water is investigated in molecular dynamics simulations. The dephasing time (T2) of the O–H stretch in bulk water calculated from the frequency fluctuation time correlation function (Cω(t)) is in the range of 70–80 femtosecond (fs), which is comparable to the characteristic timescale obtained from the vibrational echo peak shift measurements using infrared photon echo [W.P. de Boeij, M.S. Pshenichnikov, D.A. Wiersma, Ann. Rev. Phys. Chem. 49 (1998) 99]. The ultrafast decay of Cω(t) is found to be responsible for the ultrashort T2 in bulk water. Careful analysis reveals the following two interesting reasons for the ultrafast decay of Cω(t). (A) The large amplitude angular jumps of water molecules (within 30–40 fs time duration) provide a large scale contribution to the mean square vibrational frequency fluctuation and gives rise to the rapid spectral diffusion on 100 fs time scale. (B) The projected force, due to all the atoms of the solvent molecules on the oxygen (FO(t)) and hydrogen (FH(t)) atom of the O–H bond exhibit a large negative cross-correlation (NCC). We further find that this NCC is partly responsible for a weak, non-Arrhenius temperature dependence of the dephasing rate.

Total cross-section at LHC from minijets and soft gluon resummation in the infrared region

A model for total cross-sections incorporating QCD jet cross-sections and soft gluon resummation is described and compared with present data on pp and pp cross-sections. Predictions for LHC are presented for different parameter sets. It is shown that they differ according to the small x-behaviour of available parton density functions.

Infrared gluons, intrinsic transverse momentum and rising total cross-sections

We discuss the infrared limit for soft gluon k(t)-resummation and relate it to physical observables such as the intrinsic transverse momentum and the high energy limit of total cross-sections.

Facile enantiospecific synthesis of (+)-iso-cladospolide B

Enantiospecific synthesis of bio-active butenolide (+)-iso-cladospolide B from D-(-)-tartaric acid in a short synthetic sequence is presented. Pivotal reaction sequence includes cross metathesis of an alkene and Wittig olefination. (C) 2010 Elsevier Ltd. All rights reserved.

Kaupunkilaisen elinympäristöongelma : Käsitteellistämistavat ja puuttumisen mallit

The study analyses the reaction of urban residents to problems, i.e. disturbing factors, in their living environment, and also their ways of doing something about these problems. It is based on urban-sociological theory on everyday life in a modern metropolis. On this theoretical basis, problems in the urban living environment are analysed in terms of a policy of everyday interference: when urban citizens become aware of a problem in their environment, they face a pattern of behaviour where the norm is polite indifference and negative solidarity. They may feel they ought to do something about the problem, but at the same time, an implicit rule of urban life is not to interfere with other people s lives so they won t interfere with yours. For example, it is not that easy for someone disturbed by littering to complain directly to those who litter the streets. Or if you complain about tobacco smoke from the neighbour s balcony, your neighbours might get cross. Direct interference with a problem in the environment usually implies an encounter with a hitherto unknown counterpart and their possible counter-reaction. The risk is either to lose face or get into downright conflict. Therefore, an easier way may be to complain to the city authorities. The Helsinki City Environment Centre is currently working on solutions for all the various kinds of problems that occur in a dense urban structure. Various ways of conceptualising the problems in the living environment are analysed empirically using theme interviews made with citizens having contacted Helsinki City Environment Centre. A phenomenographic approach and a theory-based categorisation are applied on the analysis of the theme interviews. On the grounds of the analysis, the ways of conceptualising are determined by 1) the difficulty of interfering and convincing other people, which in practice means meddling in other people s business, 2) a territorial struggle for space and a place in a dense urban structure, 3) breaches of rules and norms for social routines in urban life, and 4) a crumbling of the urban identity and all that goes along with that. The analysis of the ways of conceptualisation is deepened using a cultural risk theory. The final outcome of the analysis is four types of behaviour among urban residents with regard to interference with everyday problems in the living environment. They have been called yard police , fence builder , park warden and environmental caretaker . The study combines an urban-sociological approach with the theoretical tradition of urban research and with research on municipal environmental policy.

Novel application of a discrete choice experiment to identify preferences for a national healthcare-associated infection surveillance programme: A cross-sectional study

Objective: To identify key stakeholder preferences and priorities when considering a national healthcare-associated infection (HAI) surveillance programme through the use of a discrete choice experiment (DCE). Setting: Australia does not have a national HAI surveillance programme. An online web-based DCE was developed and made available to participants in Australia. Participants: A sample of 184 purposively selected healthcare workers based on their senior leadership role in infection prevention in Australia. Primary and secondary outcomes: A DCE requiring respondents to select 1 HAI surveillance programme over another based on 5 different characteristics (or attributes) in repeated hypothetical scenarios. Data were analysed using a mixed logit model to evaluate preferences and identify the relative importance of each attribute. Results: A total of 122 participants completed the survey (response rate 66%) over a 5-week period. Excluding 22 who mismatched a duplicate choice scenario, analysis was conducted on 100 responses. The key findings included: 72% of stakeholders exhibited a preference for a surveillance programme with continuous mandatory core components (mean coefficient 0.640 (p<0.01)), 65% for a standard surveillance protocol where patient-level data are collected on infected and non-infected patients (mean coefficient 0.641 (p<0.01)), and 92% for hospital-level data that are publicly reported on a website and not associated with financial penalties (mean coefficient 1.663 (p<0.01)). Conclusions: The use of the DCE has provided a unique insight to key stakeholder priorities when considering a national HAI surveillance programme. The application of a DCE offers a meaningful method to explore and quantify preferences in this setting.

Asymmetric cross-coupled differential pair configuration to realize neuron activation function and its derivative

In this brief, we present a new circuit technique to generate the sigmoid neuron activation function (NAF) and its derivative (DNAF). The circuit makes use of transistor asymmetry in cross-coupled differential pair to obtain the derivative. The asymmetry is introduced through external control signal, as and when required. This results in the efficient utilization of the hard-ware by realizing NAF and DNAF using the same building blocks. The operation of the circuit is presented in the subthreshold region for ultra low-power applications. The proposed circuit has been experimentally prototyped and characterized as a proof of concept on the 1.5-mum AMI technology.

Measurement of Particle Production and Inclusive Differential Cross Sections in pbar{p} Collisions at sqrt{s}=1.96 TeV

We report a set of measurements of particle production in inelastic pbar{p} collisions collected with a minimum-bias trigger at the Tevatron Collider with the CDF II experiment. The inclusive charged particle transverse momentum differential cross section is measured, with improved precision, over a range about ten times wider than in previous measurements. The former modeling of the spectrum appears to be incompatible with the high particle momenta observed. The dependence of the charged particle transverse momentum on the event particle multiplicity is analyzed to study the various components of hadron interactions. This is one of the observable variables most poorly reproduced by the available Monte Carlo generators. A first measurement of the event transverse energy sum differential cross section is also reported. A comparison with a Pythia prediction at the hadron level is performed. The inclusive charged particle differential production cross section is fairly well reproduced only in the transverse momentum range available from previous measurements. At higher momentum the agreement is poor. The transverse energy sum is poorly reproduced over the whole spectrum. The dependence of the charged particle transverse momentum on the particle multiplicity needs the introduction of more sophisticated particle production mechanisms, such as multiple parton interactions, in order to be better explained.