Distributed Management of Massive Data: an Efficient Fine-Grain Data Access Scheme

This paper addresses the problem of efficiently storing and accessing massive data blocks in a large-scale distributed environment, while providing efficient fine-grain access to data subsets. This issue is crucial in the context of applications in the field of databases, data mining and multimedia. We propose a data sharing service based on distributed, RAM-based storage of data, while leveraging a DHT-based, natively parallel metadata management scheme. As opposed to the most commonly used grid storage infrastructures that provide mechanisms for explicit data localization and transfer, we provide a transparent access model, where data are accessed through global identifiers. Our proposal has been validated through a prototype implementation whose preliminary evaluation provides promising results

Aerial sketchmapping for monitoring forest conditions in Southern Brazil.

Aerial sketchmapping is a simple, low cost remote sensing method used for detection and mapping of forest damage caused by biotic agents (insects, pathogens and other pests) and abiotic agents (wind, fire, storms, hurricane, ice storms) in North America. This method was introduced to Brazil in 2001/2002 via a USDA Forest Service/EMBRAPA technical exchange program, which included demonstration flights, a feasibility study, workshops, production of satellite maps, observer training and operational flights, primarily for assessment of damage caused by European wood wasp (Sirex noctilio), monkeys (Cebus nigritus), armillaria root disease (Armillaria spp.), and other damaging agents in pine plantations in Southern Brazil. New applications have been investigated in the most recent campaigns, carried out in 2003 and 2004. These include the use of this technique to monitor land use changes, evaluate the accuracy of classifications from satellite imagery, and to classify successional phases in remnants of Araucaria angustifolia forests in Southern Brazil. The operational flights have demonstrated that clearcuts, land use change detection and other anthropogenic activities may be suitably mapped and monitored from the air. Future activities are aimed at consolidation of this technique in Brazil, the identification of other damage signatures, such as those caused by the eucalyptus red gum lerp psyllid (Glycaspis brimblecombei), and the use of digital aerial sketchmapping methods

Querying at Internet Scale

We are developing a distributed query processor called PIER, which is designed to run on the scale of the entire Internet. PIER utilizes a Distributed Hash Table (DHT) as its communication substrate in order to achieve scalability, reliability, decentralized control, and load balancing. PIER enhances DHTs with declarative and algebraic query interfaces, and underneath those interfaces implements multihop, in-network versions of joins, aggregation, recursion, and query/result dissemination. PIER is currently being used for diverse applications, including network monitoring, keyword-based filesharing search, and network topology mapping. We will demonstrate PIER\u27s functionality by showing system monitoring queries running on PlanetLab, a testbed of over 300 machines distributed across the globe

Extended radio emission in the galaxy cluster MS 0735.6+7421 detected with the Karl G. Jansky Very Large Array

MS 0735.6+7421 ($z = 0.216$) is a massive cool core galaxy cluster hosting one of the most powerful active galactic nuclei (AGN) outbursts known. The radio jets of the AGN have carved out an unusually large pair of X-ray cavities, each reaching a diameter of $200$ kpc. This makes MS 0735.6+7421 a unique case to investigate active galactic nuclei feedback processes, as well as other cluster astrophysics at radio wavelengths. We present new low-radio-frequency observations of MS 0735.6+7421 taken with the Karl G. Jansky Very Large Array (VLA): 5 hours of P-band ($224-480$ MHz) and 5 hours of L-band ($1-2$ GHz) observations, both in C configuration. Our VLA P-band ($224-480$ MHz) observations reveal the presence of a new diffuse radio component reaching a scale of $\sim$ $900$ kpc in the direction of the jets and of $\sim$ $500$ kpc in the direction perpendicular to the jets. This component is centered on the cluster core and has a radio power scaled at $1.4$ GHz of $P_{1.4\text{ GHz}} = (4\pm2)\times 10^{24}$ WHz$^{-1}$. Its properties are consistent with those expected from a radio mini-halo as seen in other massive cool core clusters, although it may also be associated with radio plasma that has diffused out of the X-ray cavities. Observations at higher spatial resolution are needed to fully characterize the properties and nature of this component. We also suggest that if radio mini-halos originate from jetted activity, we may be witnessing the early stages of this process.Comment: 11 pages, 7 figures, submitted to MNRA

The Iowa Homemaker vol.4, no.1

Table of Contents The Why of College Training for Motherhood by Lula R. Lancaster, page 3 Does Your Education Stop When You See a French Menu Card? by Katherine Goeppinger, page 4 April Showers by Ada Hayden, page 5 Better Homes by James Ford, page 6 All Is Not Silk That Rustles by Hazel B. McKibben, page 6 Make Your Own Bias Tape by Helen M. Green, page 7 Rejuvenating Our Homes by Lulu Robinson, page 8 Moronitis by H. B. Hawthorn, page 9 Unit Kitchens by Florence Busse, page 10 The Physically Fit Family by Grace Heidbreder, page 11 Early Spring Markets by Marvel Secor, page 11 Who’s There and Where by Dryden Quist, page 12 Editorial, page 13 The Eternal Question, page 14 Homemaker as Citizen, page 15 That Something Different by Rhea Fern Shultz, page 1

Evidence of Runaway Gas Cooling in the Absence of Supermassive Black Hole Feedback at the Epoch of Cluster Formation

Cosmological simulations, as well as mounting evidence from observations, have shown that supermassive black holes play a fundamental role in regulating the formation of stars throughout cosmic time. This has been clearly demonstrated in the case of galaxy clusters in which powerful feedback from the central black hole is preventing the hot intracluster gas from cooling catastrophically, thus reducing the expected star formation rates by orders of magnitude. These conclusions, however, have been almost entirely based on nearby clusters. Based on new Chandra X-ray observations, we present the first observational evidence for massive, runaway cooling occurring in the absence of supermassive black hole feedback in the high-redshift galaxy cluster SpARCS104922.6 + 564032.5 (z = 1.709). The hot intracluster gas appears to be fueling a massive burst of star formation (≈900 M⊙ yr⁻¹) that is offset by dozens of kpc from the central galaxy. The burst is co-spatial with the coolest intracluster gas but not associated with any galaxy in the cluster. In less than 100 million years, such runaway cooling can form the same amount of stars as in the Milky Way. Therefore, intracluster stars are not only produced by tidal stripping and the disruption of cluster galaxies, but can also be produced by runaway cooling of hot intracluster gas at early times. Overall, these observations show the dramatic impact when supermassive black hole feedback fails to operate in clusters. They indicate that in the highest overdensities, such as clusters and protoclusters, runaway cooling may be a new and important mechanism for fueling massive bursts of star formation in the early universe