Bloch oscillations of Bose-Einstein condensates: Quantum counterpart of dynamical instability

We study the Bloch dynamics of a quasi one-dimensional Bose-Einstein condensate of cold atoms in a tilted optical lattice modeled by a Hamiltonian of Bose-Hubbard type: The corresponding mean-field system described by a discrete nonlinear Schr\"odinger equation can show a dynamical (or modulation) instability due to chaotic dynamics and equipartition over the quasimomentum modes. It is shown, that these phenomena are related to a depletion of the Floquet-Bogoliubov states and a decoherence of the condensate in the many-particle description. Three different types of dynamics are distinguished: (i) decaying oscillations in the region of dynamical instability, and (ii) persisting Bloch oscillations or (iii) periodic decay and revivals in the region of stability.Comment: 12 pages, 14 figure

Spin/orbit moment imbalance in the near-zero moment ferromagnetic semiconductor SmN

SmN is ferromagnetic below 27 K, and its net magnetic moment of 0.03 Bohr magnetons per formula unit is one of the smallest magnetisations found in any ferromagnetic material. The near-zero moment is a result of the nearly equal and opposing spin and orbital moments in the 6H5/2 ground state of the Sm3+ ion, which leads finally to a nearly complete cancellation for an ion in the SmN ferromagnetic state. Here we explore the spin alignment in this compound with X-ray magnetic circular dichroism at the Sm L2,3 edges. The spectral shapes are in qualitative agreement with computed spectra based on an LSDA+U (local spin density approximation with Hubbard-U corrections) band structure, though there remain differences in detail which we associate with the anomalous branching ratio in rare-earth L edges. The sign of the spectra determine that in a magnetic field the Sm 4f spin moment aligns antiparallel to the field; the very small residual moment in ferromagnetic SmN aligns with the 4f orbital moment and antiparallel to the spin moment. Further measurements on very thin (1.5 nm) SmN layers embedded in GdN show the opposite alignment due to a strong Gd-Sm exchange, suggesting that the SmN moment might be further reduced by about 0.5 % Gd substitution

Interaksi Didalam Keluarga dengan Anak Berhadapan dengan Hukum di Panti Sosial Masurdi Putra Bambu Apus Jakarta

Keluarga merupakan lingkungan kehidupan yang dikenal anak untuk pertama kalinya, dan untuk seterusnya anak banyak belajar di dalam kehidupan keluarga. Oleh karena itu peran, sikap dan perilaku orangtua dalam proses pengasuhan anak, sangat besar pengaruhnya dalam pembentukan dan perkembangan kepribadian anak. Dengan kehadiran seorang anak dalam keluarga, komunikasi dalam keluarga menjadi lebih penting dan intensitasnya harus semakin meningkat, artinya dalam keluarga perlu ada komunikasi yang baik dan sesering mungkin antara orang tua dengan anak. Cukup banyak persoalan yang timbul di masyarakat karena atau tidak adanya komunikasi yang baik dalam keluarga. Dalam Kenyataannya, proses interaksi anak dengan orangtua tidak selalu sesuai dengan yang diharapkan dan tidaklah sesederhana yang kita bayangkan dan katakan. Pengasuhan sering dibumbui oleh berbagai hal yang tidak mendukung bagi kemandirian anak, antara lain: sikap dan perilaku orangtua yang tidak dapat menjadi contoh bagi anak-anaknya, suasana emosi anggota rumah tangga sehari-hari yang tidak kondusif, serta interaksi anggota keluarga lainnya yang tidak baik. Dengan situasi seperti itu, maka tidak semua interaksi keluarga terhadap anak efektif, akibatnya, perilaku dan kemandirian anak, tidak sesuai dengan yang diharapkan. Faktor lingkungan, seperti kemajuan teknologi informasi dan globalisasi yang berkembang pesat dewasa ini sangat mempengaruhi nilai dan norma yang berlaku dalam individu, keluarga, dan masyarakat. Hal ini dapat berakibat terjadinya berbagai permasalahan sosial pada anak diantaranya; penyimpangan perilaku baik pada anak maupun pada orang dewasa, seperti tindak kekerasan, pencurian, pelecehan seksual, tawuran dan lain- lain yang menyebabkan anak berhadapan dengan hukum (ABH)

Perbaikan Sifat Reologi Visco-Elastic Aspal Dengan Penambahan Asbuton Murni Menggunakan Parameter Complex Shear Modulus

The increasing demand of crude oil will increase the price of petroleum asphalt. Indonesia has imported asphalt to meet the need for the annually road construction and maintenance. One solution to improving the rheological properties of bitumen is by adding the harder bitumen or other chemical compound to reduce dependence to petroleum asphalt. In Indonesia there is a source of natural asphalt in Buton Island, Sulawesi with huge amount of deposit that potentially could improve the rheological properties of Pen 60/70 Petroleum Asphalt. In order to obtain a better understanding on the contribution of Asbuton to the improvement of performance on rheological properties, this research used 19 variations of Asbuton and pen 60/70 petroleum bitumen. This variation is then subjected to the basic rheology test and the mechanistic test using Dynamic Shear Rheometer. The conclusion of basic rheological performance is obtained that mixture (Asbuton and 60/70 petroleum bitumen) will increase hardness of bitumen. Conclusion on mechanistic rheological performance is that mixture (Asbuton and 60/70 petrol bitumen) will increase Performance Grade (PG) and Complex Shear Modulus (G*). The results from the analysis of Master Curve and Black Diagram, it is shown that the increasing proportion of bitumen Asbuton will decrease the phase angle (δ) but its temperature susceptibility is worse

Perbaikan Sifat Reologi Aspal Dengan Penambahan Asbuton Murni Dalam Tinjauan Modulus Kekakuan Dan Kriteria Kerusakan Perkerasan

Indonesia saat ini masih sangat tergantung pada aspal minyak untuk memenuhi kebutuhan aspal untuk pembangunan dan pemeliharaan jalan. Meningkatnya harga minyak mentah secara langsung akan meningkatkan harga aspal minyak. Salah satu cara untuk mengurangi ketergantungan terhadap aspal minyak adalah dengan memanfaatkan sumber aspal alam yang dimiliki oleh Indonesia di Pulau Buton, Sulawesi. Untuk dapat memperoleh gambaran dari perbaikan sifat reologi akibat penambahan Asbuton dilakukan pengujian sifat reologi mekanistik dengan alat Dynamic Shear Rheometer pada campuran bitumen Asbuton dan aspal Pen 60/70 dengan 19 variasi Asbuton. Dari artikel ini, kesimpulan dari sisi sifat reologi mekanistik adalah bahwa campuran bitumen Asbuton dan aspal pen 60/70 mengalami perbaikan sifat reologi mekanistik, seperti peningkatan Modulus Kekakuan Bitumen (Sbit) seiring dengan penambahan kadar Asbuton. Selanjutnya dari analisis terhadap kriteria kerusakan perkerasan, disimpulkan bahwa penambahan Asbuton akan meningkatkan ketahanan terhadap deformasi permanen, tetapi mengurangi ketahanan terhadap retak lelah. Kadar Asbuton Optimum yang direkomendasikan adalah sebesar 10%

The Morphologies of the Small Magellanic Cloud

We compare the distribution of stars of different spectral types, and hence mean age, within the central SMC and find that the asymmetric structures are almost exclusively composed of young main sequence stars. Because of the relative lack of older stars in these features, and the extremely regular distribution of red giant and clump stars in the SMC central body, we conclude that tides alone are not responsible for the irregular appearance of the central SMC. The dominant physical mechanism in determining the current-day appearance of the SMC must be star formation triggered by a hydrodynamic interaction between gaseous components. These results extend the results of population studies (cf. Gardiner and Hatzidimitriou) inward in radius and also confirm the suggestion of the spheroidal nature of the central SMC based on kinematic arguments (Dopita et al; Hardy, Suntzeff & Azzopardi). Finally, we find no evidence in the underlying older stellar population for a ``bar'' or ``outer arm'', again supporting our classification of the central SMC as a spheroidal body with highly irregular recent star formation.Comment: 8 pages, accepted for publication in ApJ Letters (higher quality figures available at http://ngala.as.arizona.edu/dennis/mcsurvey.html

Visualizing plasmon-exciton polaritons at the nanoscale using electron microscopy

Polaritons are compositional light-matter quasiparticles that have recently enabled remarkable breakthroughs in quantum and nonlinear optics, as well as in material science. Despite the enormous progress, however, a direct nanometer-scale visualization of polaritons has remained an open challenge. Here, we demonstrate that plasmon-exciton polaritons, or plexcitons, generated by a hybrid system composed of an individual silver nanoparticle and a few-layer transition metal dichalcogenide can be spectroscopically mapped with nanometer spatial resolution using electron energy loss spectroscopy in a scanning transmission electron microscope. Our experiments reveal important insights about the coupling process, which have not been reported so far. These include nanoscale variation of Rabi splitting and plasmon-exciton detuning, as well as absorption-dominated extinction signals, which in turn provide the ultimate evidence for the plasmon-exciton hybridization in the strong coupling regime. These findings pioneer new possibilities for in-depth studies of polariton-related phenomena with nanometer spatial resolution

Occurrence and Positive Predictive Value of Additional Nonmass Findings for Risk Stratification of Breast Microcalcifications in Mammography

AbstractPurposeTo assess the occurrence and positive predictive value of additional nonmass findings to stratify the risk of breast microcalcifications.MethodsThis retrospective evaluation included 278 lesions with vacuum- or image-guided hook-wire biopsy for suspicious microcalcifications. The lesions were categorized into exclusive microcalcifications and microcalcifications with focal asymmetry, tubular density or architectural distortion (ie, nonmass findings). To evaluate the utility of additional nonmass findings for risk stratification, outcome variables were positive predictive values and odds ratios for malignancy and invasive carcinoma.ResultsForty-five of 278 microcalcification lesions (16%) were associated with nonmass findings: 28 focal asymmetries, 2 tubular densities, and 15 focal asymmetries in conjunction with tubular densities. Architectural distortion was observed in 28 of these cases. The odds ratio for additional nonmass findings relative to exclusive microcalcifications was 5.9 and was statistically significant (P < .00001). Architectural distortion was the most specific indicator for malignancy and invasiveness, with odds ratios of 6.5 (P = .0072) and 5.6 (P = .0214), respectively.ConclusionsMicrocalcifications with nonmass findings were less frequent than exclusive microcalcifications but were more predictive for malignancy. Architectural distortion demonstrated the highest risk of malignancy and invasiveness. Assessment of additional nonmass findings might be useful for further risk stratification of microcalcifications, indications for additional imaging, and pretreatment considerations

Health and Its Relationship with Residential Relocations of Older People to Institutions versus to Independent Dwellings

Research into older people's relocations to independent dwellings has largely remained separate from research into moves to institutions. Yet, both types of moves could be a response to health problems and to a certain extent they could be substitutes for each other. Using Litwak and Longino's model of moves of older people, this study assesses the extent to which three commonly used health measures (limitations in activities of daily living [ADL], self-rated health, and the prevalence of [limiting] chronic conditions) predict older people's moves to subsidized care institutions and elsewhere, in one multinomial logistic regression model. The data were derived from the POLS survey for the Netherlands (N=8306) enriched with administrative data on subsequent moves. In line with Litwak and Longino's model, the findings indicate that older people's moves to institutions were more likely among those with more severe health problems, whereas moves elsewhere were more likely among those with moderate health problems. Among the three investigated health measures, limitations in ADL had the strongest predictive value, and was the only one for which the difference in effect between relocations to care institutions and relocations elsewhere was statistically significant

Analytical solution of the geodesic equation in Kerr-(anti) de Sitter space-times

The complete analytical solutions of the geodesic equations in Kerr-de Sitter and Kerr-anti-de Sitter space-times are presented. They are expressed in terms of Weierstrass elliptic p, zeta, and sigma functions as well as hyperelliptic Kleinian sigma functions restricted to the one-dimensional theta-divisor. We analyze the dependency of timelike geodesics on the parameters of the space-time metric and the test-particle and compare the results with the situation in Kerr space-time with vanishing cosmological constant. Furthermore, we systematically can find all last stable spherical and circular orbits and derive the expressions of the deflection angle of flyby orbits, the orbital frequencies of bound orbits, the periastron shift, and the Lense-Thirring effect.Comment: 18 pages, 11 figure