578 research outputs found
Negotiating Journalistic Professional Ethos in Nordic Business Journalism
News work conducted more like business creates clashes between the journalistic and managerial professional ethos of edi‐ tors. While journalists’ professional ethos includes values of self‐regulation, autonomy, and public service, managerialism promotes business ideals, measurable outcomes, and organizational efficiency—values that business journalism is claimed to support. This article aims to show how editors negotiate their work‐related ethos at the junction of two professional discourses. The article is based on 20 semi‐structured interviews of editors in four Nordic business newsrooms. The results reveal a new hybrid professional ethos that combines managerial practices with journalistic ideals. Furthermore, editors in business journalism tend to absorb managerial tendencies more easily due to close connection to financial and commercial communities. Strong journalistic principles prevail, but managerial ideals are considered a notable part of the new editorial work ethos.Peer reviewe
On nuclear matrix element uncertainties in short range 0vBB decay
The evaluation of short range contributions to neutrinoless double beta decay
has been challenged due to critics of the ansatz of the nuclear matrix element
calculations. We comment on the critics and uncertainties of these calculations
and the effect on the derived limits.Comment: 3 pages, Latex, new arguments adde
Results from the NEMO 3 experiment
The aim of the NEMO 3 experiment is the search for neutrinoless double beta
decay and precise measurement of two-neutrino double beta decay of several
isotopes. The experiment has been taking data since 2003. Since no evidence for
neutrinoless double beta decay of Mo100 and Se82 has been found, a 90% C.L.
lower limit on the half-life of this process and corresponding upper limit on
the effective Majorana neutrino mass are derived. The data are also interpreted
in terms of alternative models, such as weak right-handed currents or Majoron
emission. In addition, NEMO 3 has performed precision measurements of the
two-neutrino double beta decay for seven different isotopes. The most recent
experimental results of NEMO 3 are presented in this paper.Comment: 5 pages, 2 tables, talk at the 10th ICATPP Conference (Como, Italy, 8
- 12 October 2007
Overconstrained estimates of neutrinoless double beta decay within the QRPA
Estimates of nuclear matrix elements for neutrinoless double beta decay
(0nu2beta) based on the quasiparticle random phase approximations (QRPA) are
affected by theoretical uncertainties, which can be substantially reduced by
fixing the unknown strength parameter g_pp of the residual particle-particle
interaction through one experimental constraint - most notably through the
two-neutrino double beta decay (2nu2beta) lifetime. However, it has been noted
that the g_pp adjustment via 2\nu2\beta data may bring QRPA models in
disagreement with independent data on electron capture (EC) and single beta
decay (beta^-) lifetimes. Actually, in two nuclei of interest for 0nu2beta
decay (Mo-100 and Cd-116), for which all such data are available, we show that
the disagreement vanishes, provided that the axial vector coupling g_A is
treated as a free parameter, with allowance for g_A<1 (``strong quenching'').
Three independent lifetime data (2nu2beta, EC, \beta^-) are then accurately
reproduced by means of two free parameters (g_pp, g_A), resulting in an
overconstrained parameter space. In addition, the sign of the 2nu2beta matrix
element M^2nu is unambiguously selected (M^2nu>0) by the combination of all
data. We discuss quantitatively, in each of the two nuclei, these
phenomenological constraints and their consequences for QRPA estimates of the
0nu2beta matrix elements and of their uncertainties.Comment: Revised version (27 pages, including 10 figures), focussed on Mo-100
and Cd-116. To appear in J. Phys. G: Nucl. Phys. (2008
Study of 2b-decay of Mo-100 and Se-82 using the NEMO3 detector
After analysis of 5797 h of data from the detector NEMO3, new limits on
neutrinoless double beta decay of Mo-100 (T_{1/2} > 3.1 10^{23} y, 90% CL) and
Se-82 (T_{1/2} > 1.4 10^{23} y, 90% CL) have been obtained. The corresponding
limits on the effective majorana neutrino mass are: m < (0.8-1.2) eV and m <
(1.5-3.1) eV, respectively. Also the limits on double-beta decay with Majoron
emission are: T_{1/2} > 1.4 10^{22} y (90% CL) for Mo-100 and T_{1/2}> 1.2
10^{22} y (90%CL) for Se-82. Corresponding bounds on the Majoron-neutrino
coupling constant are g < (0.5-0.9) 10^{-4} and < (0.7-1.6) 10^{-4}.
Two-neutrino 2b-decay half-lives have been measured with a high accuracy,
T_{1/2} Mo-100 = [7.68 +- 0.02(stat) +- 0.54(syst) ] 10^{18} y and T_{1/2}
Se-82 = [10.3 +- 0.3(stat) +- 0.7(syst) ] 10^{19} y.Comment: 5 pages, 4 figure
Quantitative Imaging of Regional Aerosol Deposition, Lung Ventilation and Morphology by Synchrotron Radiation CT
To understand the determinants of inhaled aerosol particle distribution and targeting in the lung, knowledge of regional deposition, lung morphology and regional ventilation, is crucial. No single imaging modality allows the acquisition of all such data together. Here we assessed the feasibility of dual-energy synchrotron radiation imaging to this end in anesthetized rabbits; both in normal lung (n = 6) and following methacholine (MCH)-induced bronchoconstriction (n = 6), a model of asthma. We used K-edge subtraction CT (KES) imaging to quantitatively map the regional deposition of iodine-containing aerosol particles. Morphological and regional ventilation images were obtained, followed by quantitative regional iodine deposition maps, after 5 and 10 minutes of aerosol administration. Iodine deposition was markedly inhomogeneous both in normal lung and after induced bronchoconstrition. Deposition was significantly reduced in the MCH group at both time points, with a strong dependency on inspiratory flow in both conditions (R-2 = 0.71; p <0.0001). We demonstrate for the first time, the feasibility of KES CT for quantitative imaging of lung deposition of aerosol particles, regional ventilation and morphology. Since these are among the main factors determining lung aerosol deposition, we expect this imaging approach to bring new contributions to the understanding of lung aerosol delivery, targeting, and ultimately biological efficacy.Peer reviewe
Neutrinoless Double Beta Decay in Gauge Theories
Neutrinoless double beta decay is a very important process both from the
particle and nuclear physics point of view. Its observation will severely
constrain the existing models and signal that the neutrinos are massive
Majorana particles. From the elementary particle point of view it pops up in
almost every model. In addition to the traditional mechanisms, like the
neutrino mass, the admixture of right handed currents etc, it may occur due to
the R-parity violating supersymmetric (SUSY) interactions. From the nuclear
physics point of view it is challenging, because: 1) The relevant nuclei have
complicated nuclear structure. 2) The energetically allowed transitions are
exhaust a small part of all the strength. 3) One must cope with the short
distance behavior of the transition operators, especially when the intermediate
particles are heavy (eg in SUSY models). Thus novel effects, like the double
beta decay of pions in flight between nucleons, have to be considered. 4) The
intermediate momenta involved are about 100 MeV. Thus one has to take into
account possible momentum dependent terms in the nucleon current. We find that,
for the mass mechanism, such modifications of the nucleon current for light
neutrinos reduce the nuclear matrix elements by about 25 per cent, almost
regardless of the nuclear model. In the case of heavy neutrinos the effect is
much larger and model dependent.
Taking the above effects into account, the available nuclear matrix elements
for the experimentally interesting nuclei A = 76, 82, 96, 100, 116, 128, 130,
136 and 150 and the experimental limits on the life times we have extracted new
stringent limits on the average neutrino mass and on the R-parity violating
coupling for various SUSY models.Comment: Latex, 24 pages, 1 postscript figure, uses iopconf.st
Exact Baryon, Strangeness and Charge Conservation in Hadronic Gas Models
Relativistic heavy ion collisions are studied assuming that particles can be
described by a hadron gas in thermal and chemical equilibrium. The exact
conservation of baryon number, strangeness and charge are explicitly taken into
account. For heavy ions the effect arising from the neutron surplus becomes
important and leads to a substantial increase in e.g. the ratio.
A method is developed which is very well suited for the study of small systems.Comment: 5 pages, 5 Postscript figure
Measurement of double beta decay of 100Mo to excited states in the NEMO 3 experiment
The double beta decay of 100Mo to the 0^+_1 and 2^+_1 excited states of 100Ru
is studied using the NEMO 3 data. After the analysis of 8024 h of data the
half-life for the two-neutrino double beta decay of 100Mo to the excited 0^+_1
state is measured to be T^(2nu)_1/2 = [5.7^{+1.3}_{-0.9}(stat)+/-0.8(syst)]x
10^20 y. The signal-to-background ratio is equal to 3. Information about energy
and angular distributions of emitted electrons is also obtained. No evidence
for neutrinoless double beta decay to the excited 0^+_1 state has been found.
The corresponding half-life limit is T^(0nu)_1/2(0^+ --> 0^+_1) > 8.9 x 10^22 y
(at 90% C.L.).
The search for the double beta decay to the 2^+_1 excited state has allowed
the determination of limits on the half-life for the two neutrino mode
T^(2nu)_1/2(0^+ --> 2^+_1) > 1.1 x 10^21 y (at 90% C.L.) and for the
neutrinoless mode T^(0nu)_1/2(0^+ --> 2^+_1) > 1.6 x 10^23 y (at 90% C.L.).Comment: 23 pages, 7 figures, 4 tables, submitted to Nucl. Phy
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