The Arecibo Galaxy Environment Survey VII : A Dense Filament With Extremely Long HI Streams

We present completed observations of the NGC 7448 galaxy group and background volume as part of the blind neutral hydrogen Arecibo Galaxy Environment Survey (AGES). Our observations cover a region spanning 5x4 degrees, over a redshift range of approximately -2,000 < cz < 20,000 km/s. A total of 334 objects are detected, mostly in three overdensities at cz $\sim$7,500, cz $\sim$9,600 and cz $\sim$ 11,400 km/s. The galaxy density is extremely high (15 per square degree) and many ($\sim$24%) show signs of extended HI emission, including some features as much as 800 kpc in projected length. We describe the overall characteristics of this environment : kinematics, typical galaxy colours and mass to light ratios, and substructure. To aid in the cataloguing of this data set, we present a new FITS viewer (FRELLED : Fits Realtime Explorer of Low Latency in Every Dimension). This incorporates interactive source cataloguing tools which increase our source extraction speed by approximately a factor of 50.Comment: 15 pages, 13 figures, accepted for publication in MNRA

Schwarzschild-De Sitter black holes in 4+1 dimensional bulk

We construct a static solution for 4+1 dimensional bulk such that the 3+1 dimensional world has a linear warp factor and describes the Schwarzschild-dS_{4} black hole. For m=0 this four dimensional universe and Friedmann Robertson Walker universe are related with an explicit coordinate transformation. We emphasize that for linear warp factors the effect of bulk on the brane world shows up as the dS_{4} background which is favored by the big bang cosmology.Comment: 6 page

Lack of consensus in social systems

We propose an exactly solvable model for the dynamics of voters in a two-party system. The opinion formation process is modeled on a random network of agents. The dynamical nature of interpersonal relations is also reflected in the model, as the connections in the network evolve with the dynamics of the voters. In the infinite time limit, an exact solution predicts the emergence of consensus, for arbitrary initial conditions. However, before consensus is reached, two different metastable states can persist for exponentially long times. One state reflects a perfect balancing of opinions, the other reflects a completely static situation. An estimate of the associated lifetimes suggests that lack of consensus is typical for large systems.Comment: 4 pages, 6 figures, submitted to Phys. Rev. Let

Drones, Virtual Reality, and Modeling: Communicating Catastrophic Dam Failure

Dam failures occur worldwide and can be economically and ecologically devastating. Communicating the scale of these risks to the general public and decision-makers is imperative. Two-dimensional (2D) dam failure hydraulic models inform owners and floodplain managers of flood regimes but have limitations when shared with non-specialists. This study addresses these limitations by constructing a 3D Virtual Reality (VR) environment to display the 1976 Teton Dam disaster case study using a pipeline composed of (1) 2D hydraulic model data (extrapolated into 3D), (2) a 3D reconstructed dam, and (3) a terrain model processed from UAS (Uncrewed Airborne System) imagery using Structure from Motion photogrammetry. This study validates the VR environment pipeline on the Oculus Quest 2 VR Headset with the criteria: immersion fidelity, movement, immersive soundscape, and agreement with historical observations and terrain. Through this VR environment, we develop an effective method to share historical events and, with future work, improve hazard awareness; applications of this method could improve citizen engagement with Early Warning Systems. This paper establishes a pipeline to produce a visualization tool for merging UAS imagery, Virtual Reality, digital scene creation, and sophisticated 2D hydraulic models to communicate catastrophic flooding events from natural or human-made levees or dams

Reconstruction of Network Evolutionary History from Extant Network Topology and Duplication History

Genome-wide protein-protein interaction (PPI) data are readily available thanks to recent breakthroughs in biotechnology. However, PPI networks of extant organisms are only snapshots of the network evolution. How to infer the whole evolution history becomes a challenging problem in computational biology. In this paper, we present a likelihood-based approach to inferring network evolution history from the topology of PPI networks and the duplication relationship among the paralogs. Simulations show that our approach outperforms the existing ones in terms of the accuracy of reconstruction. Moreover, the growth parameters of several real PPI networks estimated by our method are more consistent with the ones predicted in literature.Comment: 15 pages, 5 figures, submitted to ISBRA 201

Scale-free Networks from Optimal Design

A large number of complex networks, both natural and artificial, share the presence of highly heterogeneous, scale-free degree distributions. A few mechanisms for the emergence of such patterns have been suggested, optimization not being one of them. In this letter we present the first evidence for the emergence of scaling (and smallworldness) in software architecture graphs from a well-defined local optimization process. Although the rules that define the strategies involved in software engineering should lead to a tree-like structure, the final net is scale-free, perhaps reflecting the presence of conflicting constraints unavoidable in a multidimensional optimization process. The consequences for other complex networks are outlined.Comment: 6 pages, 2 figures. Submitted to Europhysics Letters. Additional material is available at http://complex.upc.es/~sergi/software.ht

Studi Pendahuluan : Keberadaan Kura-kura Rote (Chelodina Mccordi, Rhodin 1994) Di Pulau Rote, Nusa Tenggara Timur

A preliminary to investigate the remaining population of Rote snake-necked turtle Chelodina mccordi in Rote Island, Nusa Tenggara Timur was conducted in 20th of May – 25 th of June 2005. Based on previously known turtle distribution and interviews with local people, we surveyed 105 locations in Rote Island. We found 35 locations in Rote island suitable for turtle habitat, in which based on interviews 26 locations were previosly known as turtle habitats but no turtles were found anymore during the last few years, and nine locations where turtles are still occasionally seen. Our survey yielded no sighting of terrapin, we only found one snake-necked turtles brought by harvester from Peto marsh. Threats to Rote snake-necked turtles are hunting, loss of habitat to agricultural conversion and polution from agricultural land, and grazing by herds. More survey need to be carried out, especially during rainy season where there are more possibility of finding this turtle