Implementation of a Low Cost For Internal Dosimetry Radiological Survey of Ionization Radiation Exposed Workers In Nuclear Medicine Services

Because the nature of the routine activities carried on in nuclear medicine services, where several not sealed radioactive sources are used, the occupational personal exposed to ionization radiation (POE) is exposed to both, internal and external radioactive contamination and direct radiation also. The most important radioisotope from the point of view of radiological risk in such Nuclear Medicine Services (NMS) is the 131I. The Mexican official regulatory organization in radiological and nuclear safety: Comisión de Seguridad Nuclear y Salvaguardias (CNSNS) specify, as a requirement in the operation license of Nuclear Medicine Services the mandatory of internal and external dosimetry survey of POE. The external dosimetry survey is normally carried out but the internal dosimetry survey is not easy to do, because internal dosimetry systems are too expensive and in Mexico there are only three organizations (CFE-CLV, ININ, CNSNS) where there are these systems but they aren ́t easily available for the Nuclear Medicine Services. Because that before fact, we propose a single, and low cost system (SLCS) to survey the internal dosimetry of POE. This system is based in a scintillation NaI(Tl) 2x2 detector and a common radiation monitor tipically used in the routine radiation and contamination measures, with a minimal infrastructure investment. This system is numerical calibrated with Montecarlo method, and compared with an well established commercial System being a good function corresponding. This system is easy to implementing in any nuclear medicine to complain the requirement of operation license in the internal dosimetry POE survey

Characterisation of Technological Innovation Management Journals

This paper seeks to characterise the publications of the technological innovation management forum. With this aim, it analyses four aspects: orientation, style, originality and readability. The information used for this study was obtained from the Emerald Management Reviews database (Emerald Group Publishing). The time period considered ran from 1996 to 2003. From the analysis, the work concludes an increasingly clear research orientation over the period. Research-Technology Management is the journal most oriented to practice. The work also finds a clear predominance of the academic style, with some room provided for the professional-journalistic style, and a certain loss of originality and readability in the publications over the period. Finally, the journals declare a more varied readership than they actually seem to have.This paper seeks to characterise the publications of the technological innovation management forum. With this aim, it analyses four aspects: orientation, style, originality and readability. The information used for this study was obtained from the Emerald Management Reviews database (Emerald Group Publishing). The time period considered ran from 1996 to 2003. From the analysis, the work concludes an increasingly clear research orientation over the period. Research-Technology Management is the journal most oriented to practice. The work also finds a clear predominance of the academic style, with some room provided for the professional-journalistic style, and a certain loss of originality and readability in the publications over the period. Finally, the journals declare a more varied readership than they actually seem to have.This paper seeks to characterise the publications of the technological innovation management forum. With this aim, it analyses four aspects: orientation, style, originality and readability. The information used for this study was obtained from the Emerald Management Reviews database (Emerald Group Publishing). The time period considered ran from 1996 to 2003. From the analysis, the work concludes an increasingly clear research orientation over the period. Research-Technology Management is the journal most oriented to practice. The work also finds a clear predominance of the academic style, with some room provided for the professional-journalistic style, and a certain loss of originality and readability in the publications over the period. Finally, the journals declare a more varied readership than they actually seem to have

Model Independent Higgs Boson Mass Limits at LEP

We derive model-independent constraints on Higgs mass and couplings from associated signals for higher masses, accessible at LEP2. This work is motivated by the fact that, in many extensions of the standard model, the Higgs boson can have substantial "invisible" decay modes, for example, into light or massless weakly interacting Goldstone bosons associated to the spontaneous violation of lepton number below the weak scale.Comment: FTUV/93-19, 13 pag + 2 figures(not included but available upon request), Late

Light Sterile Neutrino from extra dimensions and Four-Neutrino Solutions to Neutrino Anomalies

We propose a four-neutrino model which can reconcile the existing data coming from underground experiments in terms of neutrino oscillations, together with the hint from the LSND experiment and a possible neutrino contribution to the hot dark matter of the Universe. It applies the idea that extra compact dimensions, probed only by gravity and possibly gauge-singlet fields, can lower the fundamental scales such as the Planck, string or unification scales. Our fourth light neutrino $\nu_s$ ($s$ for sterile) is identified with the zero mode of the Kaluza-Klein states. To first approximation \nu_sterile combines with the nu_mu in order to form a Dirac neutrino with mass in the eV range leaving the other two neutrinos massless. The smallness of this mass scale (suitable for LSND and Hot Dark Matter) arises without appealing neither to a see-saw mechanism nor to a radiative mechanism, but from the volume factor associated with the canonical normalization of the wave-function of the bulk field in the compactified dimensions. % On the other hand the splitting between \nm and \nu_sterile (atmospheric scale) as well as the mass of the two other neutrinos (solar mass scale) arise from the violation of the fermion number on distant branes. We also discuss alternative scenarios involving flavour-changing interactions. In one of them \ne can be in the electron-volt range and therefore be probed in beta decay studies.Comment: 12 pages, latex, no figures, title changed, final version to be published in Phys Rev

Supernova Bounds on Majoron-emitting decays of light neutrinos

Neutrino masses arising from the spontaneous violation of ungauged lepton-number are accompanied by a physical Goldstone boson, generically called Majoron. In the high-density supernova medium the effects of Majoron-emitting neutrino decays are important even if they are suppressed in vacuo by small neutrino masses and/or small off-diagonal couplings. We reconsider the influence of these decays on the neutrino signal of supernovae in the light of recent Super-Kamiokande data on solar and atmospheric neutrinos. We find that majoron-neutrino coupling constants in the range 3\times 10^{-7}\lsim g\lsim 2\times 10^{-5} or g \gsim 3 \times 10^{-4} are excluded by the observation of SN1987A. Then we discuss the potential of Superkamiokande and the Sudbury Neutrino Observatory to detect majoron neutrino interactions in the case of a future galactic supernova. We find that these experiments could probe majoron neutrino interactions with improved sensitivity.Comment: 28 pages, 5 figure

Some constraints on neutral heavy leptons from flavor-conserving decays of the Z boson

Small neutrino masses can arise in some grand unified models or superstring theories. We consider a model with an enhanced fermion sector containing Dirac neutral heavy leptons. The dependence on the mass and mixing parameters of these new fermions is investigated for several measurable quantities. We study the flavor-conserving leptonic decays of the Z boson and universality breaking in these decays. We also consider the W boson mass dependence on neutral heavy lepton parameters.Comment: 20 pages, Revtex 3.0, 6 uuencoded and compressed postscript figures included. Compressed postscript file of paper, including figures, also available by anonymous ftp at ftp://ftp.physics.carleton.ca/pub/theory/gour/ocipc9411.ps.Z . Accepted for publication in Phys. Rev. D

Heavy-flavour production in Pb-Pb collisions at the LHC, measured with the ALICE detector

We present the first results from the ALICE experiment on the nuclear modification factors for heavy-flavour hadron production in Pb-Pb collisions at sqrt{s_NN}=2.76 TeV. Using proton-proton and lead-lead collision samples at sqrt{s}=7 TeV and sqrt{s_NN}=2.76 TeV, respectively, nuclear modification factors R_AA(pt) were measured for D mesons at central rapidity (via displaced decay vertex reconstruction), and for electrons and muons, at central and forward rapidity, respectively.Comment: 8 pages, 5 figures, plenary talk at Quark Matter 2011, Annecy, Franc

Tau Lepton Mixing with Charginos and its Effects on Chargino Searches at e+e- Colliders

In bilinear R-Parity violating models where a term \epsilon_3L_3H_2 is introduced in the superpotential, the tau lepton can mix with charginos. We show that this mixing is fully compatible with LEP1 precision measurements of the Z\tau\tau and W\tau\nu_\tau couplings even for large values of \epsilon_3 and of the induced vacuum expectation value v_3 of the tau-sneutrino. The single production of charginos at e+e- colliders is possible in this case and we present numerical values of the cross-section at LEP1, LEP2 and an NLC. We find maximum values of 10 pb at LEP1 and 1 fb at NLC, while the corresponding values at LEP2 are too small to observe.Comment: 16 pages (including 7 figures), LaTex, uses axodraw.sty (included

Probing neutrino non-standard interactions with atmospheric neutrino data

We have reconsidered the atmospheric neutrino anomaly in light of the laetst data from Super-Kamiokande contained events and from Super-Kamiokande and MACRO up-going muons. We have reanalysed the proposed solution to the atmospheric neutrino anomaly in terms of non-standard neutrino-matter interactions (NSI) as well as the standard nu_mu -> nu_tau oscillations (OSC). Our statistical analysis shows that a pure NSI mechanism is now ruled out at 99%, while the standard nu_mu -> nu_tau OSC mechanism provides a quite remarkably good description of the anomaly. We therefore study an extended mechanism of neutrino propagation which combines both oscillation and non-standard neutrino-matter interactions, in order to derive limits on flavour-changing (FC) and non-universal (NU) neutrino interactions. We obtain that the off-diagonal flavour-changing neutrino parameter epsilon and the diagonal non-universality neutrino parameter epsilon' are confined to -0.03 < epsilon < 0.02 and |epsilon'| < 0.05 at 99.73% CL. These limits are model independent and they are obtained from pure neutrino-physics processes. The stability of the neutrino oscillation solution to the atmospheric neutrino anomaly against the presence of non-standard neutrino interactions establishes the robustness of the near-maximal atmospheric mixing and massive-neutrino hypothesis. The best agreement with the data is obtained for Delta_m^2 = 2.3*10^{-3} eV^2, sin^2(2*theta) = 1, epsilon = 6.7*10^{-3} and epsilon' = 1.1*10^{-3}, although the chi^2 function is quite flat in the epsilon and epsilon' directions for epsilon, epsilon' -> 0.Comment: 26 pages, LaTeX file using REVTeX4, 1 table and 12 figures included. Added a revised analysis which takes into account the new 1489-day Super-Kamiokande and final MACRO data. The bound on NSI parameters is considerably improve