Aerosol-cloud-precipitation effects over Germany as simulated by a convective-scale numerical weather prediction model

Possible aerosol-cloud-precipitation effects over Germany are investigated using the COSMO model in a convection-permitting configuration close to the operational COSMO-DE. Aerosol effects on clouds and precipitation are modeled by using an advanced two-moment microphysical parameterization taking into account aerosol assumptions for cloud condensation nuclei (CCN) as well as ice nuclei (IN). Simulations of three summer seasons have been performed with various aerosol assumptions, and are analysed regarding surface precipitation, cloud properties, and the indirect aerosol effect on near-surface temperature. We find that the CCN and IN assumptions have a strong effect on cloud properties, like condensate amounts of cloud water, snow and rain as well as on the glaciation of the clouds, but the effects on surface precipitation are – when averaged over space and time – small. This robustness can only be understood by the combined action of microphysical and dynamical processes. On one hand, this shows that clouds can be interpreted as a buffered system where significant changes to environmental parameters, like aerosols, have little effect on the resulting surface precipitation. On the other hand, this buffering is not active for the radiative effects of clouds, and the changes in cloud properties due to aerosol perturbations may have a significant effect on radiation and near-surface temperature

Ink dating using thermal desorption and gas chromatography / mass spectrometry: comparison of results obtained in two laboratories

Recent ink dating methods focused mainly on changes in solvent amounts occurring over time. A promising method was developed at the Landeskriminalamt of Munich using thermal desorption (TD) followed by gas chromatography / mass spectrometry (GC/MS) analysis. Sequential extractions of the phenoxyethanol present in ballpoint pen ink entries were carried out at two different temperatures. This method is applied in forensic practice and is currently implemented in several laboratories participating to the InCID group (International Collaboration on Ink Dating). However, harmonization of the method between the laboratories proved to be a particularly sensitive and time consuming task. The main aim of this work was therefore to implement the TD-GC/MS method at the Bundeskriminalamt (Wiesbaden, Germany) in order to evaluate if results were comparable to those obtained in Munich. At first validation criteria such as limits of reliable measurements, linearity and repeatability were determined. Samples were prepared in three different laboratories using the same inks and analyzed using two TDS-GC/MS instruments (one in Munich and one in Wiesbaden). The inter- and intra-laboratory variability of the ageing parameter was determined and ageing curves were compared. While inks stored in similar conditions yielded comparable ageing curves, it was observed that significantly different storage conditions had an influence on the resulting ageing curves. Finally, interpretation models, such as thresholds and trend tests, were evaluated and discussed in view of the obtained results. Trend tests were considered more suitable than threshold models. As both approaches showed limitations, an alternative model, based on the slopes of the ageing curves, was also proposed

Mid-infrared quantum cascade detectors for applications inspectroscopy and pyrometry

In this paper, we give an overview of quantum cascade detector technology for the near- and mid-infrared wavelength range. Thanks to their photovoltaic operating principle, the most advanced quantum cascade detectors offer great opportunities in terms of high detection speed, reliable room temperature operation, and excellent Johnson noise limited detectivity. Besides some important features dealing with their fabrication and their general characteristics, we will also briefly present some possibilities for performance improvement. Elementary theoretical considerations adopted from photoconductive detectors confirm that optimization of such devices always involves various trade-off

Unconventional elasticity in smectic-A elastomers

We study two aspects of the elasticity of smectic-$A$ elastomers that make these materials genuinely and qualitatively different from conventional uniaxial rubbers. Under strain applied parallel to the layer normal, monodomain smectic-$A$ elastomers exhibit a drastic change in Young's modulus above a threshold strain value of about 3%, as has been measured in experiments by Nishikawa and Finkelmann [Macromol. Chem. Phys. {\bf 200}, 312 (1999)]. Our theory predicts that such strains induce a transition to a smectic-$C$-like state and that it is this transition that causes the change in elastic modulus. We calculate the stress-strain behavior as well as the tilt of the smectic layers and the molecular orientation for strain along the layer normal, and we compare our findings with the experimental data. We also study the electroclinic effect in chiral smectic-$A^\ast$ elastomers. According to experiments by Lehmann {\em et al}. [Nature {\bf 410}, 447 (2001)] and K\"{o}hler {\em et al}. [Applied Physics A {\bf 80}, 381 (2003)], this effect leads in smectic-$A^\ast$ elastomers to a giant or, respectively, at least very large lateral electrostriction. Incorporating polarization into our theory, we calculate the height change of smectic-$A^\ast$ elastomer films in response to a lateral external electric field, and we compare this result to the experimental findings.Comment: 12 pages, 6 figure

Nature of the spin dynamics and 1/3 magnetization plateau in azurite

We present a specific heat and inelastic neutron scattering study in magnetic fields up into the 1/3 magnetization plateau phase of the diamond chain compound azurite Cu$_3$(CO$_3$)$_2$(OH)$_2$. We establish that the magnetization plateau is a dimer-monomer state, {\it i.e.}, consisting of a chain of $S = 1/2$ monomers, which are separated by $S = 0$ dimers on the diamond chain backbone. The effective spin couplings $J_{mono}/k_B = 10.1(2)$ K and $J_{dimer}/k_B = 1.8(1)$ K are derived from the monomer and dimer dispersions. They are associated to microscopic couplings $J_1/k_B = 1(2)$ K, $J_2/k_B = 55(5)$ K and a ferromagnetic $J_3/k_B = -20(5)$ K, possibly as result of $d_{z^2}$ orbitals in the Cu-O bonds providing the superexchange pathways.Comment: 5 pages, 4 figure

Resistivity and magnetoresistance of FeSe single crystals under Helium-gas pressure

We present temperature-dependent in-plane resistivity measurements on FeSe single crystals under He-gas pressure up to 800 MPa and magnetic fields $B \leq$ 10 T. A sharp phase transition anomaly is revealed at the tetragonal-to-orthorhombic transition at $T_s$ slightly below 90 K. $T_s$ becomes reduced with increasing pressure in a linear fashion at a rate d$T_{s}$/d$P$ $\simeq$ -31 K/GPa. This is accompanied by a $P$-linear increase of the superconducting transition temperature at $T_c \sim$ 8.6 K with d$T_{c}$/d$P$ $\simeq$ +5.8 K/GPa. Pressure studies of the normal-state resistivity highlight two distinctly different regimes: for $T > T_s$, i.e., in the tetragonal phase, the in-plane resistivity changes strongly with pressure. This contrasts with the state deep in the orthorhombic phase at $T \ll T_s$, preceding the superconducting transition. Here a $T$-linear resistivity is observed the slope of which does not change with pressure. Resistivity studies in varying magnetic fields both at ambient and finite pressure reveal clear changes of the magnetoresistance, $\Delta \rho \propto B^{2}$, upon cooling through $T_s$. Our data are consistent with a reconstruction of the Fermi surface accompanying the structural transition

Intrachromosomal excision of a hybrid Ds element induces large genomic deletions in Arabidopsis

Transposon activity is known to cause chromosome rearrangements in the host genome. Surprisingly, extremely little is known about Dissociation (Ds)-induced chromosome rearrangements in Arabidopsis, where Ds is intensively used for insertional mutagenesis. Here, we describe three Arabidopsis mutants with reduced fertility and propose that excision of a hybrid Ds element induced a large genomic deletion flanking Ds. In the mutants anat and haumea, the deletion mechanism consists of a local Ds transposition from replicated into unreplicated DNA followed by Ds excision, where one end of the newly transposed element and one end of the Ds transposon at the donor site served as substrate for transposase. Excision of this hybrid element reminiscent of a macrotransposon leads to loss of the chromosomal piece located between the two ends, including one full Ds element and the flanking genomic sequence. This mechanism was found to be responsible for several other deletions and occurs at a genetically trackable frequency. Thus, it could be applied to efficiently generate deletions of various sizes in the vicinity of any existing Ds element present in the genome. In the mutant tons missing, a mechanism that involves endogenous repetitive sequences caused a large flanking deletion at a position unlinked to the starter locus. Our study of Ds transposition in Arabidopsis revealed previously undescribed mechanisms that lead to large genomic deletions flanking Ds elements, which may contribute to genome dynamics and evolution

A search for double beta decays of tin isotopes with enhanced sensitivity

A search for the various double beta decay modes of 124Sn and 112Sn has been performed on 75 kg.days of data. New half-life limits for excited states in 124Sn have been obtained including a lower limit for the decay into the first excited 2+ state of 124Te of T_half > 0.87e20 yrs (90% CL) and into the first excited 0+ state of T_half > 1.08e20 yrs (90% CL). Ground state and excited state transitions of 112Sn have also been experimentally explored. A limit for the 2 neutrino double electron capture of T_half > 1.8e19 yrs (90% CL) is obtained. The non-observation of de-excitation gammas from the 0+ at 1888.5keV results in a lower half-life limit on the 0 neutrino double electron capture decay of 112Sn of T_half > 0.8e19 yrs (90% CL), despite a possible resonant enhancement of the decay rate due to degenerated states.Comment: 6 pages, 7 figures, updated analysis and tex