Models of Saturn's Interior Constructed with Accelerated Concentric Maclaurin Spheroid Method

The Cassini spacecraft's Grand Finale orbits provided a unique opportunity to probe Saturn's gravity field and interior structure. Doppler measurements yielded unexpectedly large values for the gravity harmonics J_6, J_8, and J_10 that cannot be matched with planetary interior models that assume uniform rotation. Instead we present a suite of models that assume the planet's interior rotates on cylinders, which allows us to match all the observed even gravity harmonics. For every interior model, the gravity field is calculated self-consistently with high precision using the Concentric Maclaurin Spheroid (CMS) method. We present an acceleration technique for this method, which drastically reduces the computational cost, allows us to efficiently optimize model parameters, map out allowed parameter regions with Monte Carlo sampling, and increases the precision of the calculated J_2n gravity harmonics to match the error bars of the observations, which would be difficult without acceleration. Based on our models, Saturn is predicted to have a dense central core of 15-18 Earth masses and an additional 1.5-5 Earth masses of heavy elements in the envelope. Finally, we vary the rotation period in the planet's deep interior and determine the resulting oblateness, which we compare with the value from radio occultation measurements by the Voyager spacecraft. We predict a rotation period of 10:33:34 h +- 55s, which is in agreement with recent estimates derived from ring seismology.Comment: 12 color figures, 5 tables, Astrophysical Journal, in press (2019

Current-driven magnetization decrease in single crystalline ferromagnetic manganese oxide

The electrical and magnetic response to a bias current has been investigated in a singlecrystalline ferromagnetic manganese oxide $\Pr_{0.8}$Ca$_{0.2}$MnO$_3$ . A significant decrease of the magnetization is observed at the same threshold current where a non-linearity of V-I characteristics appears. Such a behavior cannot be understood in the framework of the filamentary picture usually invoked for the non linearity of the other manganese oxides. Instead, an analogy with spintronic features might be useful and experimental signatures seem to be in agreement with excitations of spin waves by an electric current. This provides an example of a bulk system in which the spin polarized current induces a macroscopic change in the magnetization.Comment: 3 pages, 4 figure

Lattice sites of ion-implanted Li in diamond

Published in: Appl. Phys. Lett. 66 (1995) 2733-2735 citations recorded in [Science Citation Index] Abstract: Radioactive Li ions were implanted into natural IIa diamonds at temperatures between 100 K and 900 K. Emission channelling patterns of a-particles emitted in the nuclear decay of 8Li (t1/2 = 838 ms) were measured and, from a comparison with calculated emission channelling and blocking effects from Monte Carlo simulations, the lattice sites taken up by the Li ions were quantitatively determined. A fraction of 40(5)% of the implanted Li ions were found to be located on tetrahedral interstitial lattice sites, and 17(5)% on substitutional sites. The fractions of implanted Li on the two lattice sites showed no change with temperature, indicating that Li diffusion does not take place within the time window of our measurements.

Recruitment preferences of blue mussel spat (Mytilus edulis) for different substrata and microhabitats in the White Sea

We tested the assumption that fouling pressure by the blue mussel Mytilus edulis on a small spatial scale - especially onto a given substratum type - is homogeneous. Artificial substrata were exposed to natural recruitment within and outside different microhabitats. These microhabitats were monospecific patches (diameter in the meter range) in a mixed subtidal community composed of the brown algae Laminaria saccharina, and Chorda tomentosa, the green filamentous alga Cladophora rupestris, and the blue mussel Mytilus edulis. While mussel spat settled in all microhabitats, recruitment was far from homogeneous. Within microhabitats, artificial substrata were preferred over living surfaces. Recruitment also differed between microhabitats exhibiting identical preference gradients on living surfaces and associated artificial substrata: recruitment preference for microhabitats increased in the order Laminaria saccharina < control area (stone or mud) < Chorda tomentosa < Cladophora rupestris < Mytilus edulis. In a second experimental approach on a smaller spatial scale (cm range), we assessed mussel recruitment in the vicinity of identical aliquots of some of the microhabitat-constituting species. Again, Laminaria proved to be of least, Cladophora of highest attractiveness. We conclude that primary settlement of mussel spat is not only influenced by the structure of the substratum (e.g. filamentous forms) but additionally by nearby macroorganisms - presumably by exuded chemical cues as suggested by the second experiment

Magnetocaloric effect and improved relative cooling power in (La0.7Sr0.3MnO3/SrRuO3) superlattices

Magnetic properties of a series of (La0.7Sr0.3MnO3/SrRuO3) superlattices, where the SrRuO3 layer thickness is varying, are examined. A room-temperature magnetocaloric effect is obtained owing to the finite size effect which reduces the TC of La0.7Sr0.3MnO3 layers. While the working temperature ranges are enlarged,, -DeltaSmax values remains similar to the values in polycrystalline La0.7Sr0.3MnO3. Consequently, the relative cooling powers are significantly improved, the microscopic mechanism of which is related to the effect of the interfaces at La0.7Sr0.3MnO3/SrRuO3 and higher nanostructural disorder. This study indicates that artificial oxide superlattices/multilayers might provide an alternative pathway in searching for efficient room-temperature magnetic refrigerators for (nano)microscale systems.Comment: 14^pages, 3 figures, Submitted to J. Phys. Cond. Ma

Anveshak - A Groundtruth Generation Tool for Foreground Regions of Document Images

We propose a graphical user interface based groundtruth generation tool in this paper. Here, annotation of an input document image is done based on the foreground pixels. Foreground pixels are grouped together with user interaction to form labeling units. These units are then labeled by the user with the user defined labels. The output produced by the tool is an image with an XML file containing its metadata information. This annotated data can be further used in different applications of document image analysis.Comment: Accepted in DAR 201

Diluted manganese on the bond-centered site in germanium

The functional properties of Mn-doped Ge depend to large extent on the lattice location of the Mn impurities. Here, we present a lattice location study of implanted diluted Mn by means of electron emission channeling. Surprisingly, in addition to the expected substitutional lattice position, a large fraction of the Mn impurities occupies the bond-centered site. Corroborated by ab initio calculations, the bond-centered Mn is related to Mn-vacancy complexes. These unexpected results call for a reassessment of the theoretical studies on the electrical and magnetic behavior of Mn-doped Ge, hereby including the possible role of Mn-vacancy complexes

Synthesis and Preliminary Pharmacological Evaluation of 2-[4-(Aryl substituted) piperazin-1-yl]-Nphenylacetamides: Potential Antipsychotics

Purpose: Arylpiperazines have been recognized as the largest and most diverse class of compounds exerting actions on the central nervous system with strong affinity for serotonin and dopamine receptors. We here report the synthesis of some novel arylpiperazines and their evaluation for possible antipsychotic properties.Methods: The target compounds 2-[4-(aryl substituted) piperazin-1-yl]-N-phenylacetamides (3a-j) were synthesized by first reacting aniline (1) in 2 N sodium hydroxide with chloroacetylchloride in dichloromethane to obtain 2-chloro-N-phenylacetamide (2) and subsequently treating with appropriatephenylpiperazine in acetonitrile in the presence of K2CO3 and KI. All the compounds were characterized by analytical and spectroscopic methods. The compounds were evaluated for antipsychotic activity using three animal models.Results: All the 10 new arylpipeazines showed variable antipsychotic activity with compound 3h being the least effective in the induction of catalepsy. Their effect may involve interaction with 5-HT2A and D2 receptors.Conclusion: A synthetic method and possible antipsychotic effect have been established for 2-[4-(Aryl substituted) piperazin-1-yl]-N-phenylacetamides.Keywords: N-phenylacetamide, Arylpiperazines, Antipsychotic activity, 5-HT2A, D2 antagonists