[en] This presentation described a program designed to investigate the market viability of plug-in hybrid electric vehicles (PHEVs) and examine the impact of PHEVs on electricity generation systems. Three potential charging scenarios were examined: (1) uncontrolled; (2) delayed after 22:00, and (3) optimized off-peak. The study demonstrated that PHEVs have the capacity to provide greater value to users than conventional or standard hybrid vehicles, even when their higher initial cost is considered. Fuel savings were estimated at $600 more than savings estimated for standard hybrid vehicles. Developed market models were used to demonstrate that PHEVs will probably achieve sales market shares of 26 per cent by the year 2030. An estimated 670 GWh of electricity will be needed to charge the expected fleet. Results for the uncontrolled scenario showed additional peak demands. Delayed and off-peak scenarios were capable of massive penetrations of PHEVs without increases in transmission and distribution. Incremental emission rates for sulfur dioxide (SO₂) and nitrogen oxide (NO_x) decreased in off-peak scenarios. The study showed that all PHEV charging scenarios increased SO₂ emissions when compared to standard hybrids. NO_x emissions were equal or slightly higher. It was concluded that PHEVs can also serve as a key component to alternative fuel strategies and provide significant reductions in oil imports. 30 refs., 2 tabs., 21 figs

[en] An overview is presented of the results of Dutch agriculture and horticulture for all relevant sustainability aspects, including the most recent figures and long term developments. Next to the results for the sector as a whole, attention is paid to separate types of businesses, i.e. greenhouse horticulture, dairy farms and pig farms

[en] Hamamatsu Photonics introduced a new generation of their Multi-Pixel Photon Counters in 2013 with significantly reduced after-pulsing rate. In this paper, we investigate the causes of after-pulsing by testing pre-2013 and post-2013 devices using laser light ranging from 405 to 820 nm. Doing so we investigate the possibility that afterpulsing is also due to optical photons produced in the avalanche rather than to impurities trapping charged carriers produced in the avalanches and releasing them at a later time. For pre-2013 devices, we observe avalanches delayed by ns to several 100 ns at 637, 777 nm and 820 nm demonstrating that holes created in the zero field region of the silicon bulk can diffuse back to the high field region triggering delayed avalanches. On the other hand post-2013 exhibit no delayed avalanches beyond 100 ns at 777 nm. We also confirm that post-2013 devices exhibit about 25 times lower after-pulsing. Taken together, our measurements show that the absorption of photons from the avalanche in the bulk of the silicon and the subsequent hole diffusion back to the junction was a significant source of after-pulse for the pre-2013 devices. Hamamatsu appears to have fixed this problem in 2013 following the preliminary release of our results. We also show that even at short wavelength the timing distribution exhibit tails in the sub-nanosecond range that may impair the MPPC timing performances.

[en] New technologies, especially photo-sensors, are enabling detectors for positron emission tomography to operate in large magnetic field, to be compact and to achieve excellent timing, energy and position resolutions including depth of interaction. However, the complexity and cost of such detectors are constantly increasing. Using wavelength shifting bars in a planar geometry promises to provide excellent three-dimensional position resolution with good energy and timing resolutions at a small fraction of the cost of comparable detector. Two detector configurations are being investigated using 3×3 mm² wavelength shifting bars to collect the light from either monolithic or pixelated LYSO crystals. Promising performances have been achieved.

[en] We study the spectral diversity of Type Ia supernovae (SNe Ia) at maximum light using high signal-to-noise spectrophotometry of 173 SNe Ia from the Nearby Supernova Factory. We decompose the diversity of these spectra into different extrinsic and intrinsic components, and we construct a nonlinear parameterization of the intrinsic diversity of SNe Ia that preserves pairings of “twin” SNe Ia. We call this parameterization the “Twins Embedding.” Our methodology naturally handles highly nonlinear variability in spectra, such as changes in the photosphere expansion velocity, and uses the full spectrum rather than being limited to specific spectral line strengths, ratios, or velocities. We find that the time evolution of SNe Ia near maximum light is remarkably similar, with 84.6% of the variance in common to all SNe Ia. After correcting for brightness and color, the intrinsic variability of SNe Ia is mostly restricted to specific spectral lines, and we find intrinsic dispersions as low as ∼0.02 mag between 6600 and 7200 Å. With a nonlinear three-dimensional model plus one dimension for color, we can explain 89.2% of the intrinsic diversity in our sample of SNe Ia, which includes several different kinds of “peculiar” SNe Ia. A linear model requires seven dimensions to explain a comparable fraction of the intrinsic diversity. We show how a wide range of previously established indicators of diversity in SNe Ia can be recovered from the Twins Embedding. In a companion article, we discuss how these results can be applied to the standardization of SNe Ia for cosmology.

[en] We show how spectra of Type Ia supernovae (SNe Ia) at maximum light can be used to improve cosmological distance estimates. In a companion article, we used manifold learning to build a three-dimensional parameterization of the intrinsic diversity of SNe Ia at maximum light that we call the “Twins Embedding.” In this article, we discuss how the Twins Embedding can be used to improve the standardization of SNe Ia. With a single spectrophotometrically calibrated spectrum near maximum light, we can standardize our sample of SNe Ia with an rms of 0.101 ± 0.007 mag, which corresponds to 0.084 ± 0.009 mag if peculiar velocity contributions are removed and to 0.073 ± 0.008 mag if a larger reference sample were obtained. Our techniques can standardize the full range of SNe Ia, including those typically labeled as peculiar and often rejected from other analyses. We find that traditional light-curve width + color standardization such as SALT2 is not sufficient. The Twins Embedding identifies a subset of SNe Ia, including, but not limited to, 91T-like SNe Ia whose SALT2 distance estimates are biased by 0.229 ± 0.045 mag. Standardization using the Twins Embedding also significantly decreases host-galaxy correlations. We recover a host mass step of 0.040 ± 0.020 mag compared to 0.092 ± 0.026 mag for SALT2 standardization on the same sample of SNe Ia. These biases in traditional standardization methods could significantly impact future cosmology analyses if not properly taken into account.

[en] Previously we used the Nearby Supernova Factory sample to show that Type Ia supernovae (SNe Ia) having locally star-forming environments are dimmer than SNe Ia having locally passive environments. Here we use the Constitution sample together with host galaxy data from GALEX to independently confirm that result. The effect is seen using both the SALT2 and MLCS2k2 lightcurve fitting and standardization methods, with brightness differences of 0.094 ± 0.037 mag for SALT2 and 0.155 ± 0.041 mag for MLCS2k2 with R_V = 2.5. When combined with our previous measurement the effect is 0.094 ± 0.025 mag for SALT2. If the ratio of these local SN Ia environments changes with redshift or sample selection, this can lead to a bias in cosmological measurements. We explore this issue further, using as an example the direct measurement of H ₀. GALEX observations show that the SNe Ia having standardized absolute magnitudes calibrated via the Cepheid period-luminosity relation using the Hubble Space Telescope originate in predominately star-forming environments, whereas only ∼50% of the Hubble-flow comparison sample have locally star-forming environments. As a consequence, the H ₀ measurement using SNe Ia is currently overestimated. Correcting for this bias, we find a value of $H_0^{\mathrm{c}\mathrm{o}\mathrm{r}\mathrm{r}}=$ 70.6 ± 2.6 km s^–1 Mpc^–1 when using the LMC distance, Milky Way parallaxes, and the NGC 4258 megamaser as the Cepheid zero point, and 68.8 ± 3.3 km s^–1 Mpc^–1 when only using NGC 4258. Our correction brings the direct measurement of H ₀ within ∼1 σ of recent indirect measurements based on the cosmic microwave background power spectrum.

[en] We introduce a method for identifying “twin” Type Ia supernovae (SNe Ia) and using them to improve distance measurements. This novel approach to SN Ia standardization is made possible by spectrophotometric time series observations from the Nearby Supernova Factory (SNfactory). We begin with a well-measured set of SNe, find pairs whose spectra match well across the entire optical window, and then test whether this leads to a smaller dispersion in their absolute brightnesses. This analysis is completed in a blinded fashion, ensuring that decisions made in implementing the method do not inadvertently bias the result. We find that pairs of SNe with more closely matched spectra indeed have reduced brightness dispersion. We are able to standardize this initial set of SNfactory SNe to 0.083 ± 0.012 mag, implying a dispersion of 0.072 ± 0.010 mag in the absence of peculiar velocities. We estimate that with larger numbers of comparison SNe, e.g., using the final SNfactory spectrophotometric data set as a reference, this method will be capable of standardizing high-redshift SNe to within 0.06–0.07 mag. These results imply that at least 3/4 of the variance in Hubble residuals in current SN cosmology analyses is due to previously unaccounted-for astrophysical differences among the SNe

[en] Correcting Type Ia Supernova brightnesses for extinction by dust has proven to be a vexing problem. Here we study the dust foreground to the highly reddened SN 2012cu, which is projected onto a dust lane in the galaxy NGC 4772. The analysis is based on multi-epoch, spectrophotometric observations spanning from 3300–9200 Å, obtained by the Nearby Supernova Factory. Phase-matched comparison of the spectroscopically twinned SN 2012cu and SN 2011fe across 10 epochs results in the best-fit color excess of ($E(B-<!--\; ???\; -->V)$, RMS) = (1.00, 0.03) and total-to-selective extinction ratio of (R _V, RMS) = (2.95, 0.08) toward SN 2012cu within its host galaxy. We further identify several diffuse interstellar bands and compare the 5780 Å band with the dust-to-band ratio for the Milky Way (MW). Overall, we find the foreground dust-extinction properties for SN 2012cu to be consistent with those of the MW. Furthermore, we find no evidence for significant time variation in any of these extinction tracers. We also compare the dust extinction curve models of Cardelli et al., O’Donnell, and Fitzpatrick, and find the predictions of Fitzpatrick fit SN 2012cu the best. Finally, the distance to NGC4772, the host of SN 2012cu, at a redshift of z = 0.0035, often assigned to the Virgo Southern Extension, is determined to be 16.6 ± 1.1 Mpc. We compare this result with distance measurements in the literature.

[en] We compile a sample of spectroscopically and photometrically selected cluster galaxies from four high-redshift galaxy clusters ($1.59<<!--\; <\; -->z<<!--\; <\; -->1.71$) from the Spitzer Adaptation of the Red-Sequence Cluster Survey (SpARCS), and a comparison field sample selected from the UKIDSS Deep Survey. Using near-infrared imaging from the Hubble Space Telescope, we classify potential mergers involving massive ($M_{\ast <!--\; ???\; -->}⩾<!--\; ???\; -->3\times <!--\; ??\; -->{10}^{10}{M}_{\odot <!--\; ???\; -->}$) cluster members by eye, based on morphological properties such as tidal distortions, double nuclei, and projected near neighbors within 20 kpc. With a catalog of 23 spectroscopic and 32 photometric massive cluster members across the four clusters and 65 spectroscopic and 26 photometric comparable field galaxies, we find that after taking into account contamination from interlopers, ${11.0}_{-<!--\; ???\; -->5.6}^{+7.0}\mathrm{\%<!--\; \%\; -->}$ of the cluster members are involved in potential mergers, compared to ${24.7}_{-<!--\; ???\; -->4.6}^{+5.3}\mathrm{\%<!--\; \%\; -->}$ of the field galaxies. We see no evidence of merger enhancement in the central cluster environment with respect to the field, suggesting that galaxy–galaxy merging is not a stronger source of galaxy evolution in cluster environments compared to the field at these redshifts.