Spectral averaging techniques for Jacobi matrices

Spectral averaging techniques for one-dimensional discrete Schroedinger operators are revisited and extended. In particular, simultaneous averaging over several parameters is discussed. Special focus is put on proving lower bounds on the density of the averaged spectral measures. These Wegner type estimates are used to analyze stability properties for the spectral types of Jacobi matrices under local perturbations

Exploring the Impact of Soccer Camp on Social Identity for Youth with Cerebral Palsy

Background: The purpose of this study was to explore the impact of an exclusive, residential cerebral palsy (CP) soccer camp on social identity for youth with CP. Using a phenomenological approach, the aim of this study was to explain the six-day CP soccer camp experience from the camper\u27s perspective, guided by the three processes of Social Identity Theory (SIT), to determine if a CP soccer camp setting impacted the development of the participant\u27s social identity. Methods: Semi-structured interviews were collected online through a video software from 13 participants who were purposefully sampled between the ages of 10-18. Qualitative data was initially analyzed through a deductive coding lens, then further analyzed through an inductive coding process. Results: Findings suggest that participation in an exclusive, residential CP soccer camp supported two of the three processes in SIT and provided opportunities for youth with CP to feel connected and similar to others with disabilities. Participants enjoyed being around other individuals with CP in a supportive sport environment. Conclusion: This study indicated that CP soccer camp assisted in the camper\u27s social identity development in two of the three processes of SIT. Future research implications are discussed

The PSI-U1 snRNP interaction regulates male mating behavior in Drosophila

Alternative pre-mRNA splicing (AS) is a critical regulatory mechanism that operates extensively in the nervous system to produce diverse protein isoforms. Fruitless AS isoforms have been shown to influence male courtship behavior, but the underlying mechanisms are unknown. Using genome-wide approaches and quantitative behavioral assays, we show that the P-element somatic inhibitor (PSI) and its interaction with the U1 small nuclear ribonucleoprotein complex (snRNP) control male courtship behavior. PSI mutants lacking the U1 snRNP-interacting domain (PSIΔAB mutant) exhibit extended but futile mating attempts. The PSIΔAB mutant results in significant changes in the AS patterns of ∼1,200 genes in the Drosophila brain, many of which have been implicated in the regulation of male courtship behavior. PSI directly regulates the AS of at least one-third of these transcripts, suggesting that PSI-U1 snRNP interactions coordinate the behavioral network underlying courtship behavior. Importantly, one of these direct targets is fruitless, the master regulator of courtship. Thus, PSI imposes a specific mode of regulatory control within the neuronal circuit controlling courtship, even though it is broadly expressed in the fly nervous system. This study reinforces the importance of AS in the control of gene activity in neurons and integrated neuronal circuits, and provides a surprising link between a pleiotropic pre-mRNA splicing pathway and the precise control of successful male mating behavior

Work and information processing in a solvable model of Maxwell's demon

We describe a minimal model of an autonomous Maxwell demon, a device that delivers work by rectifying thermal fluctuations while simultaneously writing information to a memory register. We solve exactly for the steady-state behavior of our model, and we construct its phase diagram. We find that our device can also act as a "Landauer eraser", using externally supplied work to remove information from the memory register. By exposing an explicit, transparent mechanism of operation, our model offers a simple paradigm for investigating the thermodynamics of information processing by small systems.Comment: Main Text (6 pages, 3 figures) + Suppl. Info. (3 pages). To appear in PNA

DNS++: Dynamic Name Resolution with Homomorphic Encryption Based Privacy

This paper presents DNS++, a re-design of the Internet's name resolution system that addresses dynamic information and privacy. DNS++ uses a pub/sub overlay to send updates about a given service to interested clients, allowing them to (re)select between replicas according to their requirements, as updates about services and their features dynamically change. Since third-party brokers in the overlay are not always trusted for the confidentiality of the content flowing through them, clients' privacy is preserved in DNS++ through homomorphic encryption. Brokers are prevented from accessing encrypted service information but can perform homomorphic match and forward service updates to relevant clients through the overlay accordingly. Assuming that forwarding tables in each broker are implemented via ordered data structures, the time required for adding a new client's subscription, and to perform homomorphic match between existing subscriptions and service updates, would grow logarithmically with the number of entries within a table. This is shown by our performance evaluation, which confirms that DNS++ is feasible to be deployed with an acceptable performance overhead

Scalable Peer-to-Peer Streaming for Live Entertainment Content

We present a system for streaming live entertainment content over the Internet originating from a single source to a scalable number of consumers without resorting to centralized or provider-provisioned resources. The system creates a peer-to-peer overlay network, which attempts to optimize use of existing capacity to ensure quality of service, delivering low startup delay and lag in playout of the live content. There are three main aspects of our solution: first, a swarming mechanism that constructs an overlay topology for minimizing propagation delays from the source to end consumers; second, a distributed overlay anycast system that uses a location-based search algorithm for peers to quickly find the closest peers in a given stream; and finally, a novel incentive mechanism that encourages peers to donate capacity even when the user is not actively consuming content

Beyond Node Degree: Evaluating AS Topology Models

This is the accepted version of 'Beyond Node Degree: Evaluating AS Topology Models', archived originally at arXiv:0807.2023v1 [cs.NI] 13 July 2008.Many models have been proposed to generate Internet Autonomous System (AS) topologies, most of which make structural assumptions about the AS graph. In this paper we compare AS topology generation models with several observed AS topologies. In contrast to most previous works, we avoid making assumptions about which topological properties are important to characterize the AS topology. Our analysis shows that, although matching degree-based properties, the existing AS topology generation models fail to capture the complexity of the local interconnection structure between ASs. Furthermore, we use BGP data from multiple vantage points to show that additional measurement locations significantly affect local structure properties, such as clustering and node centrality. Degree-based properties, however, are not notably affected by additional measurements locations. These observations are particularly valid in the core. The shortcomings of AS topology generation models stems from an underestimation of the complexity of the connectivity in the core caused by inappropriate use of BGP data

Organic Carbon Burial following the Middle Eocene Climatic Optimum (MECO) in the central - western Tethys

We present trace metal geochemistry and stable isotope records for the middle Eocene Alano di Piave section, NE Italy, deposited during magnetochron C18n in the marginal Tethys Ocean. We identify a $\sim$ 500 kyr long carbon isotope perturbation event we infer to be the middle Eocene Climatic Optimum (MECO) confirming the northern hemisphere expression and global occurrence of MECO. Interpreted peak climatic conditions are followed by the rapid deposition of two organic rich intervals ($\le$3\% TOC) and contemporaneous positive $\delta^{13}$C excursions. These two intervals are associated with increases in the concentration of sulphur and redox-sensitive trace metals, and low concentrations of Mn, as well as coupled with the occurrence of pyrite. Together these changes imply low, possibly dysoxic, bottom water O$_{2}$ conditions promoting increased organic carbon burial. We hypothesize that this rapid burial of organic carbon lowered global {\it p}CO$_{2}$ following the peak warming and returned the climate system to the general Eocene cooling trend