3,375 research outputs found
Bose-Einstein condensation in random directed networks
We consider the phenomenon of Bose-Einstein condensation in a random growing directed net-
work. The network grows by the addition of vertices and edges. At each time step the network
gains a vertex with probabilty p and an edge with probability 1 − p. The new vertex has a fitness
(a, b) with probability f(a, b). A vertex with fitness (a, b), in-degree i and out-degree j gains a new incoming edge with rate a(i + 1) and an outgoing edge with rate b(j + 1). The Bose-Einstein condensation occurs as a function of fitness distribution f(a, b)
New direction for gamma-rays
The origin of energetic gamma-ray bursts is still unknown. But the detection
of polarization of gamma-rays provides fresh insight into the mechanism driving
these powerful explosions.Comment: Nature "News & Views", RE Coburn & Boggs (astro-ph/0305377
A non extensive approach for DNA breaking by ionizing radiation
Tsallis entropy and a maximum entropy principle allows to reproduce experimental data of DNA double strand breaking by electron and neutron radiation. Analytic results for the probability of finding a DNA segment of length l are obtained reproducing quite well the fragment distribution function experimentally obtained
Correlated edge overlaps in multiplex networks
This work was partially supported by the FET proactive IP project MULTIPLEX 317532. G.J.B. was supported by the FCT Grant No. SFRH/BPD/74040/2010
The Melanoma Care Study: Protocol of a randomised controlled trial of a psycho-educational intervention for melanoma survivors at high risk of developing new primary disease
Background: Despite a good prognosis for most melanoma survivors, many experience substantial fear of new or recurrent melanoma, worry and anxiety about the future, and unmet healthcare needs. In this protocol, we outline the design and methods of the Melanoma Care Study for melanoma survivors at high risk of developing new primary disease. The objective of this study is to evaluate the efficacy and cost-effectiveness of a psycho-educational intervention for improving psychological and behavioural adjustment to melanoma risk. Design: The study design is a two-arm randomised controlled trial comparing a psycho-educational intervention to usual care. Methods: The intervention is comprised of a newly-developed psycho-educational booklet and three telephone sessions delivered by a trained psychologist. A total of 154 melanoma survivors at high risk of developing new primary disease who are attending one of three melanoma high risk clinics in New South Wales, Australia, will be recruited. Participants will be assessed at baseline (6 weeks before their high risk clinic dermatological appointment), and then 4 weeks and 6 months after their appointment. If effectiveness of the intervention is demonstrated at 6 months, an additional assessment at 12 months is planned. The primary outcome is fear of new or recurrent melanoma, as assessed by the Fear of Cancer Recurrence Inventory (FCRI). Secondary outcomes include anxiety, depression, unmet supportive care needs, satisfaction with clinical care, knowledge, behavioural adjustment to melanoma risk, quality of life, and cost-effectiveness of the intervention from a health system perspective. Following the intention-to-treat principle, linear mixed models will be used to analyse the data to account for repeated measures. A process evaluation will also be carried out to inform and facilitate potential translation and implementation into clinical practice. Discussion: This study will provide high quality evidence on the efficacy and cost-effectiveness of a psycho-educational intervention aimed at improving psychological and behavioural adjustment amongst melanoma survivors at high risk of new primary disease
Calogero-Sutherland Approach to Defect Blocks
Extended objects such as line or surface operators, interfaces or boundaries
play an important role in conformal field theory. Here we propose a systematic
approach to the relevant conformal blocks which are argued to coincide with the
wave functions of an integrable multi-particle Calogero-Sutherland problem.
This generalizes a recent observation in 1602.01858 and makes extensive
mathematical results from the modern theory of multi-variable hypergeometric
functions available for studies of conformal defects. Applications range from
several new relations with scalar four-point blocks to a Euclidean inversion
formula for defect correlators.Comment: v2: changes for clarit
Climate Dynamics: A Network-Based Approach for the Analysis of Global Precipitation
Precipitation is one of the most important meteorological variables for defining the climate dynamics, but the spatial patterns of precipitation have not been fully investigated yet. The complex network theory, which provides a robust tool to investigate the statistical interdependence of many interacting elements, is used here to analyze the spatial dynamics of annual precipitation over seventy years (1941-2010). The precipitation network is built associating a node to a geographical region, which has a temporal distribution of precipitation, and identifying possible links among nodes through the correlation function. The precipitation network reveals significant spatial variability with barely connected regions, as Eastern China and Japan, and highly connected regions, such as the African Sahel, Eastern Australia and, to a lesser extent, Northern Europe. Sahel and Eastern Australia are remarkably dry regions, where low amounts of rainfall are uniformly distributed on continental scales and small-scale extreme events are rare. As a consequence, the precipitation gradient is low, making these regions well connected on a large spatial scale. On the contrary, the Asiatic South-East is often reached by extreme events such as monsoons, tropical cyclones and heat waves, which can all contribute to reduce the correlation to the short-range scale only. Some patterns emerging between mid-latitude and tropical regions suggest a possible impact of the propagation of planetary waves on precipitation at a global scale. Other links can be qualitatively associated to the atmospheric and oceanic circulation. To analyze the sensitivity of the network to the physical closeness of the nodes, short-term connections are broken. The African Sahel, Eastern Australia and Northern Europe regions again appear as the supernodes of the network, confirming furthermore their long-range connection structure. Almost all North-American and Asian nodes vanish, revealing that extreme events can enhance high precipitation gradients, leading to a systematic absence of long-range patterns
Retinal nerve fibre layer thickness profile in normal eyes using third-generation optical coherence tomography
Aims To establish four normal retinal nerve fibre layer (RNFL) thickness radial profiles based on third-generation optical coherence tomography (OCT) and to compare them with previously reported histologic measurements.Methods A total of 20 normal eyes were studied. A circular scan was adjusted to the size of the optic disc and three scans were performed with this radius and every 200 mu m thereafter, up to a distance of 1400 mu m. Four different radial sections (superotemporal, superonasal, inferonasal, and inferotemporal) were studied to establish RNFL thickness OCT profiles. Additionally, two radial scans orientated at 45 and 1351 crossing the optic disc centre were performed in six of 20 eyes, and RNFL thickness was measured at disc margin.Results Quadrant location and distance from disc margin interaction in RNFL thickness was statistically significant (P < 0.001). the RNFL thickness decreased (P < 0.001) as the distance from the disc margin increased for all sections. the measurements automatically generated by the OCT built-in software were thinner (P < 0.001) than histologic ones close to the disc margin.Conclusions Four normal OCT RNFL profiles were established and compared with histological data obtained from the same area. RNFL measurements assessed by OCT 3 were significantly thinner close to the optic disc margin.Hosp Olhos Araraquara, Glaucoma Sect, BR-14802530 Araraquara, SP, BrazilHosp Olhos Araraquara, Retina Diagnost & Treatment Div, BR-14802530 Araraquara, SP, BrazilUniversidade Federal de São Paulo, São Paulo, BrazilUSP, Inst Fis Sao Carlos, Sao Carlos, SP, BrazilUniv So Calif, Doheny Eye Inst, Dept Ophthalmol, Los Angeles, CA USAUniversidade Federal de São Paulo, São Paulo, BrazilWeb of Scienc
Exploration of the Eucalyptus globulus gene pool
The first Europeans to discover Eucalyptus
globulus were French explorers in 1792. Its seed
was rapidly spread throughout the world in the
19th century and this was the species by which
much of the world first knew the genus.
However, it was in the industrial forests of the
20th century that this species, once considered
the ‘Prince of Eucalypts’, achieved greatest
prominence due to its fast growth and superior
pulp qualities. Formal breeding first commenced
in 1966 in Portugal and in the late 1980’s large
base population trials from open-pollinated seed
collections from native stands were established
in many countries. These trials have provided
unprecedented insights into the quantitative
genetic control of numerous traits of economic
and ecological importance and how this variation
is spatially distributed in the native range of the
species. However with large, fully pedigreed
breeding populations becoming available for
quantitative analysis and the rapidly expanding
knowledge of DNA sequence variation, we are
now at the threshold of a new understanding of
this important eucalypt gene pool. Indications of
the significance of non-additive genetic effects
are becoming available. The E. globulus
chloroplast genome has now been sequenced
and several genome maps have been published.
Studies of the variation in nuclear microsatellites
and the lignin biosynthesis gene CCR confirm
the complex, spatially structured nature of the
native gene pool. Strong spatial structuring of
the chloroplast genome has provided a tool for
tracking seed migration and the geographic
origin of exotic landraces. Highly divergent
lineages of chloroplast DNA have been
discovered and studies of the hypervariable JLA+
region argue that some components of the E.
globulus gene pool have been assimilated from
other species following hybridisation
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