Light spin-1/2 or spin-0 Dark Matter particles

We recall and precise how light spin-0 particles could be acceptable Dark Matter candidates, and extend this analysis to spin-1/2 particles. We evaluate the (rather large) annihilation cross sections required, and show how they may be induced by a new light neutral spin-1 boson U. If this one is vectorially coupled to matter particles, the (spin-1/2 or spin-0) Dark Matter annihilation cross section into e+e- automatically includes a v_dm^2 suppression factor at threshold, as desirable to avoid an excessive production of gamma rays from residual Dark Matter annihilations. We also relate Dark Matter annihilations with production cross sections in e+e- scatterings. Annihilation cross sections of spin-1/2 and spin-0 Dark Matter particles are given by exactly the same expressions. Just as for spin-0, light spin-1/2 Dark Matter particles annihilating into e+e- could be responsible for the bright 511 keV gamma ray line observed by INTEGRAL from the galactic bulge.Comment: 10 page

Kinematics of disk galaxies in (proto-)clusters at z=1.5

We observed star-forming galaxies at z~1.5 selected from the HyperSuprimeCam Subaru Strategic Program. The galaxies are part of two significant overdensities of [OII] emitters identified via narrow-band imaging and photometric redshifts from grizy photometry. We used VLT/KMOS to carry out Halpha integral field spectroscopy of 46 galaxies in total. Ionized gas maps, star formation rates and velocity fields were derived from the Halpha emission line. We quantified morphological and kinematical asymmetries to test for potential gravitational (e.g. galaxy-galaxy) or hydrodynamical (e.g. ram-pressure) interactions. Halpha emission was detected in 36 targets. 34 of the galaxies are members of two (proto-)clusters at z=1.47, confirming our selection strategy to be highly efficient. By fitting model velocity fields to the observed ones, we determined the intrinsic maximum rotation velocity Vmax of 14 galaxies. Utilizing the luminosity-velocity (Tully-Fisher) relation, we find that these galaxies are more luminous than their local counterparts of similar mass by up to ~4 mag in the rest-frame B-band. In contrast to field galaxies at z<1, the offsets of the z~1.5 (proto-)cluster galaxies from the local Tully-Fisher relation are not correlated with their star formation rates but with the ratio between Vmax and gas velocity dispersion sigma_g. This probably reflects that, as is observed in the field at similar redshifts, fewer disks have settled to purely rotational kinematics and high Vmax/sigma_g ratios. Due to relatively low galaxy velocity dispersions (sigma_v < 400 km/s) of the (proto-)clusters, gravitational interactions likely are more efficient, resulting in higher kinematical asymmetries, than in present-day clusters. (abbr.)Comment: Accepted for publication in A&A. 11 pages, 8 figures, 1 tabl

Science Verification Results from PMAS

PMAS, the Potsdam Multi-Aperture Spectrophotometer, is a new integral field instrument which was commissioned at the Calar Alto 3.5m Telescope in May 2001. We report on results obtained from a science verification run in October 2001. We present observations of the low-metallicity blue compact dwarf galaxy SBS0335-052, the ultra-luminous X-ray Source X-1 in the Holmberg II galaxy, the quadruple gravitational lens system Q2237+0305 (the "Einstein Cross"), the Galactic planetary nebula NGC7027, and extragalactic planetary nebulae in M31. PMAS is now available as a common user instrument at Calar Alto Observatory.Comment: 4 pages, 9 figures (attached in JPEG format), Euro3D Science Workshop Proceedings, held in Cambridge May 21-23, 2003, to appear in AN (accepted

On Evidence-based Risk Management in Requirements Engineering

Background: The sensitivity of Requirements Engineering (RE) to the context makes it difficult to efficiently control problems therein, thus, hampering an effective risk management devoted to allow for early corrective or even preventive measures. Problem: There is still little empirical knowledge about context-specific RE phenomena which would be necessary for an effective context- sensitive risk management in RE. Goal: We propose and validate an evidence-based approach to assess risks in RE using cross-company data about problems, causes and effects. Research Method: We use survey data from 228 companies and build a probabilistic network that supports the forecast of context-specific RE phenomena. We implement this approach using spreadsheets to support a light-weight risk assessment. Results: Our results from an initial validation in 6 companies strengthen our confidence that the approach increases the awareness for individual risk factors in RE, and the feedback further allows for disseminating our approach into practice.Comment: 20 pages, submitted to 10th Software Quality Days conference, 201

Spin-wave spectrum of copper metaborate in the commensurate phase 10K<T<21K

We have investigated the spin-wave spectrum of copper metaborate, CuB$_2$O$_4$, by means of inelastic neutron scattering in the commensurate magnetic phase. We have found two branches of spin-wave excitations associated with the two magnetic sublattices Cu(A) and Cu(B), respectively. In the temperature regime $10K \le T \le 21K$, where only the Cu(A) magnetic moments are ordered, the interaction between the two sublattices is found to be negligible. With this approximation we have determined the `easy plane' exchange parameters of the Cu(A) subsystem within standard spin-wave theory.Comment: 4 figure

The effect of prior alcohol consumption on the ataxic response to alcohol in high-alcohol preferring mice

We have previously shown that ethanol-naïve high-alcohol preferring (HAP) mice, genetically predisposed to consume large quantities of alcohol, exhibited heightened sensitivity and more rapid acute functional tolerance (AFT) to alcohol-induced ataxia compared to low-alcohol preferring mice. The goal of the present study was to evaluate the effect of prior alcohol self-administration on these responses in HAP mice. Naïve male and female adult HAP mice from the second replicate of selection (HAP2) underwent 18 days of 24-h, 2-bottle choice drinking for 10% ethanol vs. water, or water only. After 18 days of fluid access, mice were tested for ataxic sensitivity and rapid AFT following a 1.75 g/kg injection of ethanol on a static dowel apparatus in Experiment 1. In Experiment 2, a separate group of mice was tested for more protracted AFT development using a dual-injection approach where a second, larger (2.0 g/kg) injection of ethanol was given following the initial recovery of performance on the task. HAP2 mice that had prior access to alcohol exhibited a blunted ataxic response to the acute alcohol challenge, but this pre-exposure did not alter rapid within-session AFT capacity in Experiment 1 or more protracted AFT capacity in Experiment 2. These findings suggest that the typically observed increase in alcohol consumption in these mice may be influenced by ataxic functional tolerance development, but is not mediated by a greater capacity for ethanol exposure to positively influence within-session ataxic tolerance

The effect of cod liver oil and orange juice on the gastric acidity of dogs made anemic by hemorrhage

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