In this study, we investigate the consequences of organizational change that consist of adding new categories to the portfolio of humanitarian organizations. Our aim is to discern differences in ...these consequences between specialist and generalist organizations. Previous research has shown that spanning categories lead to disadvantages in the evaluation of organizations by audience members in terms of the attention they receive from the audience but did not focus on the distinction between specialists, organizations that have no history in spanning categories, and generalists, organizations that have already done so in the past. Using fixed effect logit regression methods on project approval among 2480 non-governmental organizations (NGOs) in the humanitarian sector, we show that category spanning is tantamount to risky organizational change for specialist organizations, which leads to a reduction in project approval. However, generalists benefit from category spanning, which indicates identity reinforcement. We also show that in the case of urgent demand, spanning categories has a less detrimental effect. Consequently, organizations that have successfully undergone a change from a specialist to a generalist identity no longer suffer from category spanning. Moreover, also situations of urgent demand reduce the negative consequences of category spanning.
The data taken with the ANTARES neutrino telescope from 2007 to 2010, a total live time of 863 days, are used to measure the oscillation parameters of atmospheric neutrinos. Muon tracks are ...reconstructed with energies as low as 20 GeV. Neutrino oscillations will cause a suppression of vertical upgoing muon neutrinos of such energies crossing the Earth. The parameters determining the oscillation of atmospheric neutrinos are extracted by fitting the event rate as a function of the ratio of the estimated neutrino energy and reconstructed flight path through the Earth. Measurement contours of the oscillation parameters in a two-flavour approximation are derived. Assuming maximal mixing, a mass difference of Δm322=(3.1±0.9)⋅10−3eV2 is obtained, in good agreement with the world average value.
A frequency domain model has been developed to describe squeal noise of rail-bound vehicles generated by unstable lateral creepage between wheel and rail. The model is based on a combination of ...existing models for contact mechanics, contact dynamics, wheel dynamics and rail dynamics, which are transformed into the frequency domain. The relation between friction coefficient and lateral creepage is linearized to allow frequency domain calculations. This enables fast calculations and enhances insight into frequency-dependent phenomena relating to squeal. In addition to existing models, the variation of the normal contact force is implemented in the model. This addition to the model is essential to explain several effects. One of these effects is the influence of the lateral contact position on the wheel tread on squeal noise; squeal noise by lateral creepage only occurs for a certain contact position interval.
A laboratory test rig (scale 1:3) was designed to validate the model. Two measurements will be presented in this paper. The friction coefficient of the rolling contact is measured as a function of lateral creepage, for cases with and without squeal (but with the similar contact surface conditions), giving different results. The required wheel damping to prevent squeal noise is measured as a function of the lateral contact position. The test rig has been used for model validation and will be used to evaluate and optimize particular measures against squeal noise. The model can be used as a design tool for measures against squeal noise by lateral creepage.
A search for high-energy neutrino emission correlated with gamma-ray bursts outside the electromagnetic prompt-emission time window is presented. Using a stacking approach of the time delays between ...reported gamma-ray burst alerts and spatially coincident muon-neutrino signatures, data from the
Antares
neutrino telescope recorded between 2007 and 2012 are analysed. One year of public data from the
IceCube
detector between 2008 and 2009 have been also investigated. The respective timing profiles are scanned for statistically significant accumulations within 40 days of the Gamma Ray Burst, as expected from Lorentz Invariance Violation effects and some astrophysical models. No significant excess over the expected accidental coincidence rate could be found in either of the two data sets. The average strength of the neutrino signal is found to be fainter than one detectable neutrino signal per hundred gamma-ray bursts in the
Antares
data at 90% confidence level.
The AMADEUS (ANTARES Modules for the Acoustic Detection Under the Sea) system which is described in this article aims at the investigation of techniques for acoustic detection of neutrinos in the ...deep sea. It is integrated into the ANTARES neutrino telescope in the Mediterranean Sea. Its acoustic sensors, installed at water depths between 2050 and 2300
m, employ piezo-electric elements for the broad-band recording of signals with frequencies ranging up to 125
kHz. The typical sensitivity of the sensors is around −145
dB
re
1
V/
μ
Pa
(including preamplifier). Completed in May 2008, AMADEUS consists of six “acoustic clusters”, each comprising six acoustic sensors that are arranged at distances of roughly 1
m from each other. Two vertical mechanical structures (so-called lines) of the ANTARES detector host three acoustic clusters each. Spacings between the clusters range from 14.5 to 340
m. Each cluster contains custom-designed electronics boards to amplify and digitise the acoustic signals from the sensors. An on-shore computer cluster is used to process and filter the data stream and store the selected events. The daily volume of recorded data is about 10
GB. The system is operating continuously and automatically, requiring only little human intervention. AMADEUS allows for extensive studies of both transient signals and ambient noise in the deep sea, as well as signal correlations on several length scales and localisation of acoustic point sources. Thus the system is excellently suited to assess the background conditions for the measurement of the bipolar pulses expected to originate from neutrino interactions.
► Magnetic monopoles are hypothetical particles predicted in unified theories. ► Relativistic monopoles could be detected in a neutrino telescope. ► A search for upgoing monopoles has been performed ...using 2008 ANTARES data. ► The obtained flux limits are stronger than limits from other experiments.
Magnetic monopoles are predicted in various unified gauge models and could be produced at intermediate mass scales. Their detection in a neutrino telescope is facilitated by the large amount of light emitted compared to that from muons. This paper reports on a search for upgoing relativistic magnetic monopoles with the ANTARES neutrino telescope using a data set of 116days of live time taken from December 2007 to December 2008. The one observed event is consistent with the expected atmospheric neutrino and muon background, leading to a 90% C.L. upper limit on the monopole flux between 1.3×10−17 and 8.9×10−17cm−2s−1sr−1 for monopoles with velocity β⩾0.625.
► A method to search for neutrinos from transient sources with ANTARES is presented. ► High energy single neutrinos or low energy multiplets can trigger alerts. ► Alerts are sent within a minute to a ...network of optical telescopes. ► A telescopes network can search for optical counterparts of neutrino alerts. ► ANTARES has a median angular precision of about 0.5 degrees above 10TeV.
The ANTARES telescope has the capability to detect neutrinos produced in astrophysical transient sources. Potential sources include gamma-ray bursts, core collapse supernovae, and flaring active galactic nuclei. To enhance the sensitivity of ANTARES to such sources, a new detection method based on coincident observations of neutrinos and optical signals has been developed. A fast online muon track reconstruction is used to trigger a network of small automatic optical telescopes. Such alerts are generated for special events, such as two or more neutrinos, coincident in time and direction, or single neutrinos of very high energy.
Risk Factors for Voice Problems in Teachers Kooijman, P.G.C.; de Jong, F.I.C.R.S.; Thomas, G. ...
Folia phoniatrica et logopaedica,
01/2006, Letnik:
58, Številka:
3
Journal Article
Recenzirano
In order to identify factors that are associated with voice problems and voice-related absenteeism in teachers, 1,878 questionnaires were analysed. The questionnaires inquired about personal data, ...voice complaints, voice-related absenteeism from work and conditions that may lead to voice complaints and absenteeism. Different factors play a role in the development and consolidation of voice problems. Physical and psycho-emotional factors appear to be the most important risk factors. Remarkably, voice load and environment seem to be less important as risk factors in the development and consolidation of voice complaints. Teachers who experienced voice problems during their training reported more voice problems during their career. The results of this study stress the importance of a multifactorial approach in the diagnosis and treatment of voice problems, whereby physical and psycho-emotional aspects should be considered as sensitive to the risk of developing voice problems. Moreover, this study shows the crucial importance of adequate voice training during the teacher training programme.
Analysis of the Fermi-LAT data has revealed two extended structures above and below the Galactic Centre emitting gamma rays with a hard spectrum, the so-called Fermi bubbles. Hadronic models ...attempting to explain the origin of the Fermi bubbles predict the emission of high-energy neutrinos and gamma rays with similar fluxes. The ANTARES detector, a neutrino telescope located in the Mediterranean Sea, has a good visibility to the Fermi bubble regions. Using data collected from 2008 to 2011 no statistically significant excess of events is observed and therefore upper limits on the neutrino flux in TeV range from the Fermi bubbles are derived for various assumed energy cutoffs of the source.
The Antares detector has been in operation for more than one year. Data taking with the first detector string has continued uninterrupted for 16 months starting from March 2006. A further four ...detector strings were connected to the read out in January 2007. With this almost half-size detector the first neutrinos have been observed.
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