Using deuterated H3+ and other molecular species to understand the formation of stars and planets

The H3+ ion plays a key role in the chemistry of dense interstellar gas clouds where stars and planets are forming. The low temperatures and high extinctions of such clouds make direct observations of H3+ impossible, but lead to large abundances of H2D+ and D2H+ which are very useful probes of the early stages of star and planet formation. Maps of H2D+ and D2H+ pure rotational line emission toward star-forming regions show that the strong deuteration of H3+ is the result of near-complete molecular depletion of CNO-bearing molecules onto grain surfaces, which quickly disappears as cores warm up after stars have formed. In the warmer parts of interstellar gas clouds, H3+ transfers its proton to other neutrals such as CO and N2, leading to a rich ionic chemistry. The abundances of such species are useful tracers of physical conditions such as the radiation field and the electron fraction. Recent observations of HF line emission toward the Orion Bar imply a high electron fraction, and we suggest that observations of OH+ and H2O+ emission may be used to probe the electron density in the nuclei of external galaxies.Comment: Proceedings of the H3+ centennial symposium, to be published in RSPTA (editor: T. Oka

Testing the Disk Regulation Paradigm with Spitzer Observations. II. A Clear Signature of Star-Disk Interaction in NGC 2264 and the Orion Nebula Cluster

Observations of PMS star rotation periods reveal slow rotators in young clusters of various ages, indicating that angular momentum is somehow removed from these rotating masses. The mechanism by which spin-up is regulated as young stars contract has been one of the longest-standing problems in star formation. Attempts to observationally confirm the prevailing theory that magnetic interaction between the star and its circumstellar disk regulates these rotation periods have produced mixed results. In this paper, we use the unprecedented disk identification capability of the Spitzer Space Telescope to test the star-disk interaction paradigm in two young clusters, NGC 2264 and the Orion Nebula Cluster (ONC). We show that once mass effects and sensitivity biases are removed, a clear increase in the disk fraction with period can be observed in both clusters across the entire period range populated by cluster members. We also show that the long-period peak (P $\sim$8 days) of the bimodal distribution observed for high-mass stars in the ONC is dominated by a population of stars possessing a disk, while the short-period peak (P $\sim$2 days) is dominated by a population of stars without a disk. Our results represent the strongest evidence to date that star-disk interaction regulates the angular momentum of these young stars. This study will make possible quantitative comparisons between the observed period distributions of stars with and without a disk and numerical models of the angular momentum evolution of young stars.Comment: 31 pages, 7 figures, 2 tables. Accepted for publication in Ap

Gampong Pande, Situs Penting di Ujung Utara Pulau Sumatera

Aceh is rich a variation of objects - intact or fragmentary - containing material history and worth studying. Gampong Pande in Banda Aceh, The historical-archaeological data of Gampong Pande hasn\u27t been read and used as a historical source. The site is vital for an introduction the Aceh role related entry and development of Islam in Indonesia, also related with harbor at the estuary of Aceh River. Lately, archaeological-historical research has done there. Results of activity are information about a variety objects of archaeology and history such as tomb/tombstones, fragments ceramic/pottery, currency dirham, and the remaining structures and shaft. Related results of the survey and excavation, it can be suspected since the 14th century Gampong Pande was a part of the trading port, a place of exchange. Grave and tombstones partially show the style of tomb and Aceh tombstone until the 16th century to the 17th century. The dirham findings validate the historical record that the kingdom of Aceh using it as a means of payment. Activities were noisy at least until the 17th century. Then Gampong Pande left, do not be a place before. Later in the 19th century, Gampong Pande back reuse for activities. Old shaft excavation result shows a high level of life. Making shaft with ring pottery/clay show quality people who are not arbitrary

Situs Kota Rebah di Tanjung Pinang, Kepulauan Riau: Pertapakan Istana atau Bangunan Lain

An excavation at the site of Kota Rebah (also known as Kota Lama) in the city of Tanjung Pinang, Kepulauan Riau (Riau Islands) Province in October 2014, which was carried out by the Cultural Office of Kepulauan Riau Province, in cooperation with the Medan Archaeological Centre and the Cultural Heritage Conservation Office of Batusangkar, is an attempt to explore remains of the cultural history of Kepulauan Riau community, including to understand about their types and functions. This is in relation to the site and remains of a building that is believed by some local inhabitants to be a site and remains of the palace of the Melayu kings in the past. The data collected using survey and excavation method indicate that the site and building remains are more likely to be remains of a loji (fort with warehouses) than the site and remains of a palace

Random walks in directed modular networks

Because diffusion typically involves symmetric interactions, scant attention has been focused on studying asymmetric cases. However, important networked systems underlain by diffusion (e.g. cortical networks and WWW) are inherently directed. In the case of undirected diffusion, it can be shown that the steady-state probability of the random walk dynamics is fully correlated with the degree, which no longer holds for directed networks. We investigate the relationship between such probability and the inward node degree, which we call efficiency, in modular networks. Our findings show that the efficiency of a given community depends mostly on the balance between its ingoing and outgoing connections. In addition, we derive analytical expressions to show that the internal degree of the nodes do not play a crucial role in their efficiency, when considering the Erd\H{o}s-R\'enyi and Barab\'asi-Albert models. The results are illustrated with respect to the macaque cortical network, providing subsidies for improving transportation and communication systems

Cosmology on a Three-Brane

In this paper a general solution is found for a five dimensional orbifold spacetime that induces a $k=0$ cosmology on a three-brane. Expressions for the energy density and pressure on the brane in terms of the brane metric are derived. Given a metric on the brane it is possible to find five dimensional spacetimes that contain the brane. This calculation is carried out for an inflationary universe and for a metric that corresponds to a radiation dominated universe in standard cosmology. It is also shown that any $k=0$ cosmology can be embedded in a flat five dimensional orbifold spacetime and the equation of the three-brane surface is derived. For an inflationary universe it is shown that the surface is the usual hyperboloid representation of de Sitter space, although it is embedded in an orbifold spacetime.Comment: 11 pages, LaTex. New solutions with a cosmological constant have been adde

Strategi Pengelolaan Kawasan Kota Cina, Medan, Provinsi Sumatera Utara

Kota Cina area is one of the areas along the east coast of North Sumatra, which is closely related to trade network in Southeast Asia since at least 12th to 14th centuries CE. Previous researchers have proven that the area had once been a thriving city of commerce, port, and settlement during the period. This research is aimed at fabricating a strategy to manage Kota Cina area. The strategy is oriented toward preservation and utilization for the sake of the community. The method used is retracing its management history, which can then be used as the basis for determining the management strategy in the future. The research has generated four strategies, namely to: assign Kota Cina as a cultural heritage area, establish a management institution, include active participation of local community members in developing this area as a tourist destination, and develop thorough research

Fuzzy logic as a decision-making support system for the indication of bariatric surgery based on an index (OBESINDEX) generated by the association between body fat and body mass index

Background: A Fuzzy Obesity Index (OBESINDEX) for use as an alternative in bariatric surgery indication (BSI) is presented. The search for a more accurate method to evaluate obesity and to indicate a better treatment is important in the world health context. BMI (body mass index) is considered the main criteria for obesity treatment and BSI. Nevertheless, the fat excess related to the percentage of Body Fat (%BF) is actually the principal harmful factor in obesity disease that is usually neglected. This paper presents a new fuzzy mechanism for evaluating obesity by associating BMI with %BF that yields a fuzzy obesity index for obesity evaluation and treatment and allows building up a Fuzzy Decision Support System (FDSS) for BSI.

Methods: Seventy-two patients were evaluated for both BMI and %BF. These data are modified and treated as fuzzy sets. Afterwards, the BMI and %BF classes are aggregated yielding a new index (OBESINDEX) for input linguistic variable are considered the BMI and %BF, and as output linguistic variable is employed the OBESINDEX, an obesity classification with entirely new classes of obesity in the fuzzy context as well is used for BSI.

Results: There is a gradual, smooth obesity classification and BSI when using the proposed fuzzy obesity index when compared with other traditional methods for dealing with obesity.

Conclusion: The BMI is not adequate for surgical indication in all the conditions and fuzzy logic becomes an alternative for decision making in bariatric surgery indication based on the OBESINDEX