2,078 research outputs found
The broad away side of azimuthal correlations: 3 vs 2 final state particles in high energy nuclear collisions
In high energy heavy ion collisions at RHIC there are important aspects of
the medium induced dynamics, that are still not well understood. In particular,
there is a broadening and even a double hump structure of the away-side peak
appearing in azimuthal correlation studies in Au+Au collisions which is absent
in p+p collisions at the same energies. These features are already present but
suppressed in p+p collisions: 2 to 3 parton processes produce such structures
but are suppressed with respect to 2 to 2 processes. We argue that in A+A
collisions the different geometry for the trajectories of 3 as opposed to 2
particles in the final state, together with the medium induced energy loss
effects on the different cross sections, create a scenario that enhances
processes with 3 particles in the final state, which gives on average this
double hump structure.Comment: Prepared for the 5th International Workshop on High-pT Physics at
LHC, ICN-UNAM, 27 Sep.-1 Oct, 201
Organic semiconductors: The effect of small modifications on device performance
Invited oral presentationIn the search on new high-mobiliity semiconductors with ambipolar performances, good processability and excellent environmental stability, diverse synthetic strategies have been approached. One of the most widely used consists in the alternation of donor and acceptor moieties in the conjugated skeleton, which allows fine tuning of the frontier molecular orbitals. For OTFT applications,low-lying HOMOs are essential to resist air oxidation and thus increase device stability. However, if the HOMO energy is too low, the resulting barrier to hole injection may compromise the transistor performance. Thus, a delicate balance between these two effects is needed. Furthermore, high performance solution-processable materials require the correct selection and positioning of the specific solubilizing substituents in order to achieve proper HOMO and LUMO energy levels, planar molecular conformations, close intermolecular pi-pi stacking, and proper thin film crystallinity. In this communication, several examples of molecular and polymeric materials where modifications on their conjugated skeletons, donor/acceptor subunits ratio and/or the selection of proper alkyl solubilizing chains induce noticeable changes in their electronic performances.Universidad de Málaga, Campus de Excelencia Internacional Andalucía Tec
Three and two-hadron correlations in \sqrt{s_{NN}}=200 GeV proton-proton and nucleus-nucleus collisions
We compare the azimuthal correlations arising from three and two hadron
production in high energy proton-proton and nucleus-nucleus collisions at
\sqrt{s_{NN}}=200 GeV, using the leading order matrix elements for two-to-three
and two-to-two parton-processes in perturbative QCD. We first compute the two
and three hadron production cross sections in mid-rapidity proton-proton
collisions. Then we consider Au + Au collisions including parton energy loss
using the modified fragmentation function approach. By examining the
geometrical paths the hard partons follow through the medium, we show that the
two away-side partons produced in two-to-three processes have in average a
smaller and a greater path length than the average path length of the away-side
parton in two-to-two processes. Therefore there is a large probability that in
the former processes one of the particles escapes while the other gets
absorbed. This effect leads to an enhancement in the azimuthal correlations of
the two-to-three with respect to the two-to-two parton-processes when comparing
to the same processes in proton-proton collisions since in average the particle
with the shortest path length looses less energy with respect to the away side
particle in two-to-two processes. We argue that this phenomenon may be
responsible for the shape of the away-side in azimuthal correlations observed
in mid-rapidity Au + Au collisions at RHIC.Comment: 4 pages, 2 figure
New Self-Sufficient Shelter Solutions for Big Cities’ Collapsed Rental Markets
Nowadays, there is a wide variety of problems in the big cities related to the urban frame and to housing. Architects have to provide solutions that not only improve people’s well-being but also have to be efficient during the building’s entire life cycle. Within the European context, big cities like Paris, Berlin and Amsterdam have a huge demand for housing coming mainly from two different groups: people looking for temporary shelter and people looking for a more stable situation. In both cases, the need for new housing have resulted in inefficient urban developments, collapsed city centres and developed satellite cities where low and medium class people have tried to find somewhere to live, running away from infra-housing. In Paris, urban regulations set the minimum area for a rented apartment as 10m2. The research described in this paper analyzes the current situation in big cities from two points of view: apartment sizes and medium fees for temporary shelter. It defines the average architectural conditions of the “affordable” shelter and with this data; an experimental approach for a new completely self-sufficient housing module is provided, placed in a worthless space of existing buildings (roofs). This new module is defined by its sustainability and self-sufficiency and it gives the rental market an opportunity to increase the offer of shelter to rent in the big cities. At the end of the research, the development of an analysis of life cost cycle of the new module shows it as an alternative to the existing examples of infra housing with very short periods for recovering the investment
Impact of Food Assistance Programs on Obesity in Mothers and Children: A Prospective Cohort Study in Peru.
Objectives. To assess obesity risk among mothers participating in Community Kitchens and children participating in Glass of Milk (Peru food assistance programs).
Methods. We analyzed prospective data from the Young Lives study. The exposure consisted in varying degrees of benefit from any of the programs (no participation in any of the programs, program participation for some months, or program participation nearly every month) at baseline (2006–2007). The outcome was overweight and obesity in mothers and children at follow-up (2009–2010).
Results. Prevalence of childhood overweight and obesity was 15.5% and 5.1%, respectively; the corresponding figures for mothers were 40.5% and 14.6%. Children exposed nearly every month to the Glass of Milk program had a 65% lower risk of becoming obese compared with children not participating in the program (relative risk [RR] = 0.35; 95% confidence interval [CI] = 0.18, 0.66). Mothers participating frequently in the Community Kitchens program had almost twice the risk of becoming obese compared with those who did not participate (RR = 1.93; 95% CI = 1.18, 3.15).
Conclusions. Participating in food assistance programs in Peru was associated with a lower risk of obesity in children and greater risk of obesity in mothers.Revisión por pare
Donor-acceptor polymers for applications in organic electronics and photovoltaics
We have synthesized a new series of high-mobility polymeric semiconductors with good processability and excellent environmental stability for organic electronics and photovoltaics. Using these materials, solar cells were fabricated with power conversion efficiencies of up to 8.7% and remarkable fill factors of 76-80%.MINECO, Junta de Andalucí
Formaciones de "Antirrhinum majus" en los territorios hispalenses
Stands of Antirrhinum majus in the Hispalense sectorPalabras clave. Asociación, sintaxonomia, corología, sur Península Ibérica, Echio boissieri-Antirrhinetum majii.Key words. Association, syntaxonomy, chorology, south of the Iberian Peninsula, Echio boissieri-Antirrhinetum majii
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