Observation of Andreev bound states in bicrystal grain-boundary Josephson junctions of the electron doped superconductor LaCeCuO

We observe a zero-bias conductance peak (ZBCP) in the ab-plane quasiparticle tunneling spectra of thin film grain-boundary Josephson junctions made of the electron doped cuprate superconductor LaCeCuO. An applied magnetic field reduces the spectral weight around zero energy and shifts it non-linearly to higher energies consistent with a Doppler shift of the Andreev bound states (ABS) energy. For all magnetic fields the ZBCP appears simultaneously with the onset of superconductivity. These observations strongly suggest that the ZBCP results from the formation of ABS at the junction interfaces, and, consequently, that there is a sign change in the symmetry of the superconducting order parameter of this compound consistent with a d-wave symmetry.Comment: 9 pages, 7 figures; December 2004, accepted for publication in Phys. Rev.

The Shared Design Space

The Shared Design Space is a novel interface for enhancing face-to- face collaboration using multiple displays and input surfaces. The system supports natural gestures and paper-pen input and overcomes the limitations of using traditional technology in co-located meetings and brainstorming activities

The evolution of HCO+^{+} in molecular clouds using a novel chemical post-processing algorithm

Modeling the internal chemistry of molecular clouds is critical to accurately simulating their evolution. To reduce computational expense, 3D simulations generally restrict their chemical modeling to species with strong heating and cooling effects. We address this by post-processing tracer particles in the SILCC-Zoom molecular cloud simulations. Using a chemical network of 39 species and 299 reactions (including freeze-out of CO and H$_2$O), and a novel iterative algorithm to reconstruct a filled density grid from sparse tracer particle data, we produce time-dependent density distributions for various species. We focus upon the evolution of HCO$^+$, which is a critical formation reactant of CO but is not typically modeled on-the-fly. We analyse the evolution of the tracer particles to assess the regime in which HCO$^+$ production preferentially takes place. We find that the HCO$^+$ content of the cold molecular gas forms in situ around n_\textrm{HCO^+}\simeq10^3-$10^4$ cm$^{-3}$, over a time-scale of approximately 1 Myr, rather than being distributed to this density regime via turbulent mixing from deeper in the cloud. We further show that the dominant HCO$^+$ formation pathway is dependent on the visual extinction, with the reaction H$_3^+$ + CO contributing 90% of the total HCO$^+$ production flux above $A_\textrm{V,3D}=3$. Using our novel grid reconstruction algorithm, we produce the very first maps of the HCO$^+$ column density, $N$(HCO$^+$), and show that it reaches values as high as $10^{15}$ cm$^{-2}$. We find that 50% of the HCO$^+$ mass is located in an $A_\textrm{V}$-range of $\sim$10-30, and in a density range of $10^{3.5}$-$10^{4.5}$ cm$^{-3}$. Finally, we compare our $N$(HCO$^+$) maps to recent observations of W49A and find good agreement.Comment: 23 pages including appendix, 20 figures, submitted to MNRAS, comments are welcom

Bridging Digital and Physical Worlds Using Tangible Drag-and-Drop Interfaces

The last ten years have seen an explosion in the diversity of digital-life devices, e.g. music and video players. However, the interaction paradigm to use these devices has remained mostly unchanged. Remote controls are still the most common way to manage a digital-life device. Moreover, the interaction between devices themselves is still very limited and rarely addressed by a remote control interface. We present in this paper a study of tangible drag-and-drop, a remote control interface based on the well-known paradigm coming from the graphical user interface. This interaction technique aims at reducing the gap between the digital and physical worlds, enabling the transfer of digital data from one device to another. To validate such a concept, we present two prototypes, along with user studies and a general discussion about the tangible drag-and-drop technique

Shunting operations at flat yards : retrieving freight railcars from storage tracks

In this paper, we study the railcar retrieval problem (RRT) where specified numbers of certain types of railcars have to be withdrawn from the storage tracks of a flat yard. This task arises in the daily operations of workshop yards for railcar maintenance. The objective is to minimize the total cost of shunting via methods such as minimizing the usage of shunting engines. We describe the RRT formally, present a mixed-integer program formulation, and prove the general case to be NP-hard. For some special cases, exact algorithms with polynomial runtimes are proposed. We also analyze several intuitive heuristic solution approaches motivated by observed real-world planning routines. We evaluate their average performances in simulations with different scenarios and provide their worst-case performance guarantee. We show that although the analyzed heuristics result in much better solutions than the naive planning approach, they are still on average 30%-50% from the optimal objective value and may result in up to 14 times higher costs in the worst case. Therefore, we conclude that optimization should be implemented in practice in order to save valuable resources. Furthermore, we analyze the impacts of yard layout and the widespread organizational routine of presorting on the railcar retrieval cost

HyGAL: Characterizing the Galactic ISM with observations of hydrides and other small molecules II. The absorption line survey with the IRAM 30 m telescope

As a complement to the HyGAL Stratospheric Observatory for Infrared Astronomy Legacy Program, we report the results of a ground-based absorption line survey of simple molecules in diffuse and translucent Galactic clouds. Using the Institut de Radioastronomie Millim\'etrique (IRAM) 30 m telescope, we surveyed molecular lines in the 2 mm and 3 mm wavelength ranges toward 15 millimeter continuum sources. These sources, which are all massive star-forming regions located mainly in the first and second quadrants of the Milky Way, form the subset of the HyGAL sample that can be observed by the IRAM 30 m telescope. We detected HCO$^+$ absorption lines toward 14 sightlines, toward which we identified 78 foreground cloud components, as well as lines from HCN, HNC, C$_2$H, and c-C$_3$H$_2$ toward most sightlines. In addition, CS and H$_2$S absorption lines are found toward at least half of the continuum sources. Static Meudon photodissociation region (PDR) isobaric models that consider ultraviolet-dominated chemistry were unable to reproduce the column densities of all seven molecular species by just a factor of a few, except for H$_2$S. The inclusion of other formation routes driven by turbulent dissipation could possibly explain the observed high column densities of these species in diffuse clouds. There is a tentative trend for H$_2$S and CS abundances relative to H$_2$ to be larger in diffuse clouds ($X$(H$_2$S) and $X$(CS) $\sim 10^{-8} - 10^{-7}$) than in translucent clouds ($X$(H$_2$S) and $X$(CS) $\sim 10^{-9} - 10^{-8}$) toward a small sample; however, a larger sample is required in order to confirm this trend. The derived H$_2$S column densities are higher than the values predicted from the isobaric PDR models, suggesting that chemical desorption of H$_2$S from sulfur-containing ice mantles may play a role in increasing the H$_2$S abundance.Comment: 41 pages, 25 figures, 10 tables, and 5 appendices. Accepted for publication in A&

Birch leaves and branches as a source of ice-nucleating macromolecules

Birch pollen are known to release ice-nucleating macromolecules (INM), but little is known about the production and release of INM from other parts of the tree. We examined the ice nucleation activity of samples from 10 different birch trees (Betula spp.). Samples were taken from nine birch trees in Tyrol, Austria, and from one tree in a small urban park in Vienna, Austria. Filtered aqueous extracts of 30 samples of leaves, primary wood (new branch wood, green in colour, photosynthetically active), and secondary wood (older branch wood, brown in colour, with no photosynthetic activity) were analysed in terms of ice nucleation activity using VODCA (Vienna Optical Droplet Crystallization Analyser), a cryo microscope for emulsion samples. All samples contained ice-nucleating particles in the submicron size range. Concentrations of ice nuclei ranged from 6.7×104 to 6.1×109&thinsp;mg−1 sample. Mean freezing temperatures varied between −15.6 and −31.3&thinsp;°C; the range of temperatures where washes of birch pollen and dilutions thereof typically freeze. The freezing behaviour of three concentrations of birch pollen washing water (initial wash, 1&thinsp;:&thinsp;100, and 1&thinsp;:&thinsp;10&thinsp;000) were significantly associated with more than a quarter of our samples, including some of the samples with highest and lowest activity. This indicates a relationship between the INM of wood, leaves, and pollen. Extracts derived from secondary wood showed the highest concentrations of INM and the highest freezing temperatures. Extracts from the leaves exhibited the highest variation in INM and freezing temperatures. Infrared spectra of the extracts and tested birch samples show qualitative similarity, suggesting the chemical components may be broadly similar.</p

Genome-Wide DNA Methylation Profiling in Early Stage I Lung Adenocarcinoma Reveals Predictive Aberrant Methylation in the Promoter Region of the Long Noncoding RNA PLUT: An Exploratory Study

Introduction: Surgical procedure is the treatment of choice in early stage I lung adenocarcinoma. However, a considerable number of patients experience recurrence within the first 2 years after complete resection. Suitable prognostic biomarkers that identify patients at high risk of recurrence (who may probably benefit from adjuvant treatment) are still not available. This study aimed at identifying methylation markers for early recurrence that may become important tools for the development of new treatment modalities. Methods: Genome-wide DNA methylation profiling was performed on 30 stage I lung adenocarcinomas, comparing 14 patients with early metastatic recurrence with 16 patients with a long-term relapse-free survival period using methylated-CpG-immunoprecipitation followed by high-throughput next-generation sequencing. The differentially methylated regions between the two subgroups were validated for their prognostic value in two independent cohorts using the MassCLEAVE assay, a high-resolution quantitative methylation analysis. Results: Unsupervised clustering of patients in the discovery cohort on the basis of differentially methylated regions identified patients with shorter relapse-free survival (hazard ratio: 2.23; 95% confidence interval: 0.66-7.53; p = 0.03). In two validation cohorts, promoter hypermethylation of the long noncoding RNA PLUT was significantly associated with shorter relapse-free survival (hazard ratio: 0.54; 95% confidence interval: 0.31-0.93; p < 0.026) and could be reported as an independent prognostic factor in the multivariate Cox regression analysis. Conclusions: Promoter hypermethylation of the long noncoding RNA PLUT is predictive in patients with early stage I adenocarcinoma at high risk for early recurrence. Further studies are needed to validate its role in carcinogenesis and its use as a biomarker to facilitate patient selection and risk stratification