Scalable Overlay Multicast Tree Construction for QoS-Constrained Media Streaming

Overlay networks have become popular in recent times for content distribution and end-system multicasting of media streams. In the latter case, the motivation is based on the lack of widespread deployment of IP multicast and the ability to perform end-host processing. However, constructing routes between various end-hosts, so that data can be streamed from content publishers to many thousands of subscribers, each having their own QoS constraints, is still a challenging problem. First, any routes between end-hosts using trees built on top of overlay networks can increase stress on the underlying physical network, due to multiple instances of the same data traversing a given physical link. Second, because overlay routes between end-hosts may traverse physical network links more than once, they increase the end-to-end latency compared to IP-level routing. Third, algorithms for constructing efficient, large-scale trees that reduce link stress and latency are typically more complex. This paper therefore compares various methods to construct multicast trees between end-systems, that vary in terms of implementation costs and their ability to support per-subscriber QoS constraints. We describe several algorithms that make trade-offs between algorithmic complexity, physical link stress and latency. While no algorithm is best in all three cases we show how it is possible to efficiently build trees for several thousand subscribers with latencies within a factor of two of the optimal, and link stresses comparable to, or better than, existing technologies

Hollow Core, Whispering Gallery Resonator Sensors

A review of hollow core whispering gallery resonators (WGRs)is given. After a short introduction to the topic of whispering gallery resonators we provide a description of whispering gallery modes in hollow or liquid core WGRs. Next, whispering gallery mode (WGM) sensing mechanisms are outlined and some fabrication methods for microbubbles, microcapillaries and other tubular WGM devices are discussed. We then focus on the most common applications of hollow core WGRs, namely refractive index and temperature sensing, gas sensing, force sensing, biosensing, and lasing. The review highlights some of the key papers in this field and gives the reader a general overview of the current state-of-the-art

Life, Liberty, and the Pursuit of Rum: The Phenomenon of Liberalism in British Pirate Law

Seventeenth and eighteenth century British pirates abided by simple legal codes aboard their ships. These codes determined what was and was not allowed, how punishments were determined and doled out, and how loot and rations were divided. What is most significant about these codes, however, is how remarkably progressive they were as legal documents, not unlike the liberalism being developed contemporaneously in Europe. Progressive policies began pragmatically in order to maintain control as pirate captains had no traditional legitimacy, but evolved into a true liberal legal tradition as pirates formed socio-political groups. The legal punishments and guarantees of rights found in pirate codes demonstrate just how progressive pirate codes were for their time. This trend is most apparent when surviving pirate codes are compared directly to contemporary British naval law found in the Articles of War (1661). Additionally, as codes were shared and passed on to successors, the development of a legal tradition and isolation from legitimate society reveals that pirates are a demographic that must be examined by historians not as criminal organizations, but as socio-political and even creole communities.</p

Mutable Protection Domains: Towards a Component-Based System for Dependable and Predictable Computing

The increasing complexity of software poses signicant challenges for real-time and embedded systems beyond those based purely on timeliness. With embedded sys-tems and applications running on everything from mobile phones, PDAs, to automobiles, aircraft and beyond, an emerging challenge is to ensure both the functional and tim-ing correctness of complex software. We argue that static analysis of software is insufcient to verify the safety of all possible control ow interactions. Likewise, a static sys-tem structure upon which software can be isolated in sepa-rate protection domains, thereby dening immutable bound-aries between system and application-level code, is too in-exible to the challenges faced by real-time applications with explicit timing requirements. This paper, therefore, in-vestigates a concept called mutable protection domains that supports the notion of hardware-adaptable isolation boundaries between software components. In this way, a system can be dynamically recongured to maximize soft-ware fault isolation, increasing dependability, while guar-anteeing various tasks are executed according to specic time constraints. Using a series of simulations on multi-dimensional, multiple-choice knapsack problems, we show how various heuristics compare in their ability to rapidly reorganize the fault isolation boundaries of a component-based system, to ensure resource constraints while simulta-neously maximizing isolation benet. Our ssh oneshot algorithm offers a promising approach to address system dynamics, including changing component invocation pat-terns, changing execution times, and mispredictions in iso-lation costs due to factors such as caching. This material is based upon work supported by the National Science Foundation under Grant Numbers 0615153 and 0720464. Any opinions, ndings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reect the views of the National Science Foundation.

Ultrafast photoisomerisation of an isolated retinoid

The photoinduced excited state dynamics of gas-phase trans-retinoate (deprotonated trans-retinoic acid, trans-RA−) are studied using tandem ion mobility spectrometry coupled with laser spectroscopy, and frequency-, angle- and time-resolved photoelectron imaging. Photoexcitation of the bright S3(ππ*) ← S0 transition leads to internal conversion to the S1(ππ*) state on a ≈80 fs timescale followed by recovery of S0 and concomitant isomerisation to give the 13-cis (major) and 9-cis (minor) photoisomers on a ≈180 fs timescale. The sub-200 fs stereoselective photoisomerisation parallels that for the retinal protonated Schiff base chromophore in bacteriorhodopsin. Measurements on trans-RA− in methanol using the solution photoisomerisation action spectroscopy technique show that 13-cis-RA− is also the principal photoisomer, although the 13-cis and 9-cis photoisomers are formed with an inverted branching ratio with photon energy in methanol when compared with the gas phase, presumably due to solvent-induced modification of potential energy surfaces and inhibition of electron detachment processes. Comparison of the gas-phase time-resolved data with transient absorption spectroscopy measurements on retinoic acid in methanol suggest that photoisomerisation is roughly six times slower in solution. This work provides clear evidence that solvation significantly affects the photoisomerisation dynamics of retinoid molecules

Modal Q Factor and Modal Overlap of Electrically Small Avionics Box

Estimating the electromagnetic field strength in avionics boxes and other small enclosures at the design stage requires an estimate of the Q factor of the cavity modes. When the enclosure is small, it is typically under-moded so that Q measurement techniques which are standard practice in over-moded reverberation chambers may not be a robust measure. Furthermore, practical antenna used to measure Q in a small cavity may have a strong influence on the result obtained, as reported by Tait et al, IEEE Trans. EMC 55 2 2012. This paper reports the results of testing to determine the Q factor of a small aperture enclosure, used in a statistical power balance model to predict the electric field strength. The contributors to the total Q are identified. A novel S(sub 11) curve fitting method to measure modal Q is introduced and compared with the time domain method for measuring Q

The measurement of compassionate leadership:Adaptation and Spanish validation of the compassionate leadership self-reported scale

Background: A culture of shared leadership is widespread among palliative care teams based on a commitment to valuing and including all people equally. As compassion is a core value for palliative care work, compassionate leadership may be the best way to lead in palliative care. Aims: The aims of this study were twofold: 1) to adapt and validate the Compassionate Leadership Self-reported Scale in a sample of palliative care professionals; and 2) to study the relation between compassionate leadership and associated concepts of selfcompassion, awareness, and self-care. Methods: A cross-sectional survey of 296 Spanish palliative care professionals was conducted. Analyses included descriptive statistics, a confirmatory factor analysis (CFA) with four-correlated factors, reliability estimates, and a structural model. Results: Results suggested there were medium to high levels of compassionate leadership in the sample. The CFA showed an adequate overall fit: χ2(98)=277.595 (p<.001); CFI=.986; SRMR=.047; RMSEA=.088[.076,.100]. Reliability estimates for four subscales of compassionate leadership (attending, understanding, empathizing and helping) were also adequate, ranging from .72 to .96. Finally, the structural model predicting compassionate leadership suggested that the dimensions of attending and understanding were most highly related to positive self-compassion and awareness; empathizing, to self-care and awareness; and helping, to positive self-compassion and self-care. Conclusion: The Compassionate Leadership Scale has adequate psychometric properties when used to assess compassionate leadership in the context of palliative care. Our results indicate that self-compassion, awareness, and self-care are important correlates of such compassionate leadership

Life-course origins of social inequalities in adult immune cell markers of inflammation in developing southern Chinese population: the Guangzhou Biobank Cohort Study

BackgroundSocioeconomic position (SEP) throughout life is associated with cardiovascular disease, though the mechanisms linking these two are unclear. It is also unclear whether there are critical periods in the life course when exposure to better socioeconomic conditions confers advantages or whether SEP exposures accumulate across the whole life course. Inflammation may be a mechanism linking socioeconomic position (SEP) with cardiovascular disease. In a large sample of older residents of Guangzhou, in southern China, we examined the association of life course SEP with inflammation. MethodsIn baseline data on 9,981 adults (≥ 50 years old) from the Guangzhou Biobank Cohort Study (2006-08), we used multivariable linear regression and model fit to assess the associations of life course SEP at four stages (childhood, early adult, late adult and current) with white blood, granulocyte and lymphocyte cell counts. ResultsA model including SEP at all four life stages best explained the association of life course SEP with white blood and granulocyte cell count for men and women, with early adult SEP (education) making the largest contribution. A critical period model best explained the association of life course SEP with lymphocyte count, with sex-specific associations. Early adult SEP was negatively associated with lymphocytes for women. ConclusionsLow SEP throughout life may negatively impact late adult immune-inflammatory status. However, some aspects of immune-inflammatory status may be sensitive to earlier exposures, with sex-specific associations. The findings were compatible with the hypothesis that in a developing population, upregulation of the gonadotropic axis with economic development may obscure the normally protective effects of social advantage for men