Thermal transient analysis of TI8 tunnel

The TI8 tunnel will house a proton beam transfer line of 450 GeV from the SPS to the LHC collider. This line will comprise 340 classical compact design magnets which are expected to dissipate about 120 W/m to the air along the tunnel. As the ventilation injection and extraction points are separated by approximately 2.5 Km (the length of the tunnel), a significant increase in the air bulk temperature is expected along the distance. This report presents an estimation of the air temperature evolution with time at the end of the tunnel

Phonon Linewidths and Electron Phonon Coupling in Nanotubes

We prove that Electron-phonon coupling (EPC) is the major source of broadening for the Raman G and G- peaks in graphite and metallic nanotubes. This allows us to directly measure the optical-phonon EPCs from the G and G- linewidths. The experimental EPCs compare extremely well with those from density functional theory. We show that the EPC explains the difference in the Raman spectra of metallic and semiconducting nanotubes and their dependence on tube diameter. We dismiss the common assignment of the G- peak in metallic nanotubes to a Fano resonance between phonons and plasmons. We assign the G+ and G- peaks to TO (tangential) and LO (axial) modes.Comment: 5 pages, 4 figures (correction in label of fig 3

Duration of Low Wage Employment: A Study Based on a Survival Model

This paper includes a survival analysis which attempts to explain the duration, as in the number of years a worker remains in a low wage situation. Explanatory variables take into account the characteristics of the employee, such as education, age, tenure with the company, gender and nationality, and the characteristics of the job and the company such as industry affiliation, number of employees, age of the company and location.low wage, survival, Portugal

Basal-plane Incommensurate Phases in HCP Structures

An Ising model with competing interaction is used to study the appearance of incommensurate phases in the basal plane of an hexagonal closed-packed structure. The calculated mean-field phase diagram reveals various 1q-incommensurate and lock-in phases. The results are applied to explain the basal-plane incommensurate phase in some compounds of the A'A"BX_4 family, like K_2MoO_4, K_2WO_4, Rb_2WO4 and to describe the sequence of high-temperature phase transitions in other compounds of this family.Comment: 8 pages, RevTeX + 4 ps figure

Observation of the Kohn anomaly near the K point of bilayer graphene

The dispersion of electrons and phonons near the K point of bilayer graphene was investigated in a resonant Raman study using different laser excitation energies in the near infrared and visible range. The electronic structure was analyzed within the tight-binding approximation, and the Slonczewski-Weiss-McClure (SWM) parameters were obtained from the analysis of the dispersive behavior of the Raman features. A softening of the phonon branches was observed near the K point, and results evidence the Kohn anomaly and the importance of considering electron-phonon and electron-electron interactions to correctly describe the phonon dispersion in graphene systems.Comment: 4 pages, 4 figure

Owls (Strigiformes) in Parque Nacional Peneda-Gerês (PNPG) – Portugal

Owls (Strigiformes) are particularly difficult to study and the existing information is still scarce. In PNPG area there are records of the seven species present in Portugal; the Long-eared Owl and the Short-eared Owl are here occasional species. This work aims to determine the distribution, density and abundance of Strigiformes in PNPG (Northwest of Portugal). Between December 2007 and June 2008, 106 passive hearing point counts of 15 minutes each were done in the centre of each of 106 squares (2x2 km). Distribution maps for each species were obtained. Therefore, we recorded a total of 98 contacts for Tawny Owl and 67 contacts for Scops Owl. We also obtained 7 contacts of Little Owl, 2 contacts of Barn Owl and one of Eagle Owl. The habitat selection by Scops Owl and Tawny Owl was also studied. Scops Owls seems to avoid low shrub and preferred forested areas. Tawny Owls also avoid low shrub areas, preferring forested areas, and were found in urban areas. The populations of these two species in PNPG show a considerable expansion, while the other ones reveal a marked decline regarding the previous situation. The implementation of monitoring and conservation measures is suggested to stop the decline of these three species

Percolation Effects in Very High Energy Cosmic Rays

Most QCD models of high energy collisions predict that the inelasticity $K$ is an increasing function of the energy. We argue that, due to percolation of strings, this behaviour will change and, at $\sqrt{s} \simeq 10^4$ GeV, the inelasticity will start to decrease with the energy. This has straightforward consequences in high energy cosmic ray physics: 1) the relative depth of the shower maximum $\bar{X}$ grows faster with energy above the knee; 2) the energy measurements of ground array experiments at GZK energies could be overestimated.Comment: Correction of equation (19) and figures 3 and 4. 4 pages, 4 figure