102 research outputs found
Chemokine Receptors CXCR3 and CXCR7: Allosteric Ligand Binding, Biased Signaling, and Receptor Regulation
Leurs, R. [Promotor]Smit, M.J. [Promotor
A computationally tractable version of the collective model
A computationally tractable version of the Bohr-Mottelson collective model is
presented which makes it possible to diagonalize realistic collective models
and obtain convergent results in relatively small appropriately chosen
subspaces of the collective model Hilbert space. Special features of the
proposed model is that it makes use of the beta wave functions given
analytically by the softened-beta version of the Wilets-Jean model, proposed by
Elliott et al., and a simple algorithm for computing SO(5) > SO(3) spherical
harmonics. The latter has much in common with the methods of Chacon, Moshinsky,
and Sharp but is conceptually and computationally simpler. Results are
presented for collective models ranging from the sherical vibrator to the
Wilets-Jean and axially symmetric rotor-vibrator models.Comment: 16 pages, 9 figure
P-wave excited baryons from pion- and photo-induced hyperon production
We report evidence for , , ,
, , and , and find
indications that might have a companion state at 1970\,MeV. The
controversial is not seen. The evidence is derived from a
study of data on pion- and photo-induced hyperon production, but other data are
included as well. Most of the resonances reported here were found in the
Karlsruhe-Helsinki (KH84) and the Carnegie-Mellon (CM) analyses but were
challenged recently by the Data Analysis Center at GWU. Our analysis is
constrained by the energy independent scattering amplitudes from either
KH84 or GWU. The two amplitudes from KH84 or GWU, respectively, lead to
slightly different branching ratios of contributing resonances but the
debated resonances are required in both series of fits.Comment: 22 pages, 28 figures. Some additional sets of data are adde
Olber's Paradox for Superluminal Neutrinos: Constraining Extreme Neutrino Speeds at TeV-ZeV Energies with the Diffuse Neutrino Background
The only invariant speed in special relativity is c; therefore, if some
neutrinos travel at even tiny speeds above c, normal special relativity is
incomplete and any superluminal speed may be possible. I derive a limit on
superluminal neutrino speeds v >> c at high energies by noting that such speeds
would increase the size of the neutrino horizon. The increased volume of the
Universe visible leads to a brighter astrophysical neutrino background. The
nondetection of "guaranteed" neutrino backgrounds from star-forming galaxies
and ultrahigh energy cosmic rays (UHECRs) constrains v/c at TeV--ZeV energies.
I find that v/c <= 820 at 60 TeV from the nondetection of neutrinos from
star-forming galaxies. The nondetection of neutrinos from UHECRs constrains v/c
to be less than 2500 at 0.1 EeV in a pessimistic model and less than 4.6 at 4
EeV in an optimistic model. The UHECR neutrino background nondetection is
strongly inconsistent with a naive quadratic extrapolation of the OPERA results
to EeV energies. The limits apply subject to some caveats, particularly that
the expected pionic neutrino backgrounds exist and that neutrinos travel faster
than c when they pass the detector. They could be improved substantially as the
expected neutrino backgrounds are better understood and with new experimental
neutrino background limits. I also point out that extremely subluminal speeds
would result in a much smaller neutrino background intensity than expected.Comment: 13 pages, 2 figures, fixed titl
Antennas for the detection of radio emission pulses from cosmic-ray induced air showers at the Pierre Auger Observatory
The Pierre Auger Observatory is exploring the potential of the radio detection technique to study extensive air showers induced by ultra-high energy cosmic rays. The Auger Engineering Radio Array (AERA) addresses both technological and scientific aspects of the radio technique. A first phase of AERA has been operating since September 2010 with detector stations observing radio signals at frequencies between 30 and 80 MHz. In this paper we present comparative studies to identify and optimize the antenna design for the final configuration of AERA consisting of 160 individual radio detector stations. The transient nature of the air shower signal requires a detailed description of the antenna sensor. As the ultra-wideband reception of pulses is not widely discussed in antenna literature, we review the relevant antenna characteristics and enhance theoretical considerations towards the impulse response of antennas including polarization effects and multiple signal reflections. On the basis of the vector effective length we study the transient response characteristics of three candidate antennas in the time domain. Observing the variation of the continuous galactic background intensity we rank the antennas with respect to the noise level added to the galactic signal
In patients eligible for meniscal surgery who first receive physical therapy, multivariable prognostic models cannot predict who will eventually undergo surgery
Purpose Although physical therapy is the recommended treatment in patients over 45 years old with a degenerative meniscal tear, 24% still opt for meniscal surgery. The aim was to identify those patients with a degenerative meniscal tear who will undergo surgery following physical therapy. Methods The data for this study were generated in the physical therapy arm of the ESCAPE trial, a randomized clinical trial investigating the effectiveness of surgery versus physical therapy in patients of 45-70 years old, with a degenerative meniscal tear. At 6 and 24 months patients were divided into two groups: those who did not undergo surgery, and those who did undergo surgery. Two multivariable prognostic models were developed using candidate predictors that were selected from the list of the patients' baseline variables. A multivariable logistic regression analysis was performed with backward Wald selection and a cut-off of p < 0.157. For both models the performance was assessed and corrected for the models' optimism through an internal validation using bootstrapping technique with 500 repetitions. Results At 6 months, 32/153 patients (20.9%) underwent meniscal surgery following physical therapy. Based on the multivariable regression analysis, patients were more likely to opt for meniscal surgery within 6 months when they had worse knee function, lower education level and a better general physical health status at baseline. At 24 months, 43/153 patients (28.1%) underwent meniscal surgery following physical therapy. Patients were more likely to opt for meniscal surgery within 24 months when they had worse knee function and a lower level of education at baseline at baseline. Both models had a low explained variance (16 and 11%, respectively) and an insufficient predictive accuracy. Conclusion Not all patients with degenerative meniscal tears experience beneficial results following physical therapy. The non-responders to physical therapy could not accurately be predicted by our prognostic models.Orthopaedics, Trauma Surgery and Rehabilitatio
Earth, Wind and Solar Energy
Renewable energy is the energy of the future â plentiful and ubiquitous. Technological advances and economies of scale are bringing down prices, whereas fossil and nuclear are increasingly uncompetitive. Here, the Green European Journal presents in numbers how energy systems will evolve over the decades to come, while Daniel Scholten traces the new geopolitical faultlines set to supersede those of the fossil age
Earth, Wind and Solar Energy
Renewable energy is the energy of the future â plentiful and ubiquitous. Technological advances and economies of scale are bringing down prices, whereas fossil and nuclear are increasingly uncompetitive. Here, the Green European Journal presents in numbers how energy systems will evolve over the decades to come, while Daniel Scholten traces the new geopolitical faultlines set to supersede those of the fossil age
Earth, Wind and Solar Energy
Renewable energy is the energy of the future â plentiful and ubiquitous. Technological advances and economies of scale are bringing down prices, whereas fossil and nuclear are increasingly uncompetitive. Here, the Green European Journal presents in numbers how energy systems will evolve over the decades to come, while Daniel Scholten traces the new geopolitical faultlines set to supersede those of the fossil age
- âŠ