On Gauge Invariance of Breit-Wigner Propagators

We present an approach to bosonic ($Z^0, W^{\pm}$) as well as fermionic (top-quark) Breit-Wigner propagators which is consistent with gauge invariance arguments. In particular, for the $Z^0$-boson propagator we extend previous analyses and show that the part proportional to $k_{\mu} k_{\nu}/M^2$ must be modified near the resonance. We derive a mass shift which agrees with results obtained elsewhere by different methods. The modified form of a resonant heavy fermion propagator is also given.Comment: 16 p., TeX, (final version

Effectiveness of the global protected area network in representing species diversity

The Fifth World Parks Congress in Durban, South Africa, announced in September 2003 that the global network of protected areas now covers 11.5% of the planet's land surface. This surpasses the 10% target proposed a decade earlier, at the Caracas Congress, for 9 out of 14 major terrestrial biomes. Such uniform targets based on percentage of area have become deeply embedded into national and international conservation planning. Although politically expedient, the scientific basis and conservation value of these targets have been questioned. In practice, however, little is known of how to set appropriate targets, or of the extent to which the current global protected area network fulfils its goal of protecting biodiversity. Here, we combine five global data sets on the distribution of species and protected areas to provide the first global gap analysis assessing the effectiveness of protected areas in representing species diversity. We show that the global network is far from complete, and demonstrate the inadequacy of uniform—that is, 'one size fits all'—conservation targets

Clinical aspects of incorporating cord clamping into stabilisation of preterm infants

Fetal to neonatal transition is characterised by major pulmonary and haemodynamic changes occurring in a short period of time. In the international neonatal resuscitation guidelines, comprehensive recommendations are available on supporting pulmonary transition and delaying clamping of the cord in preterm infants. Recent experimental studies demonstrated that the pulmonary and haemodynamic transition are intimately linked, could influence each other and that the timing of umbilical cord clamping should be incorporated into the respiratory stabilisation. We reviewed the current knowledge on how to incorporate cord clamping into stabilisation of preterm infants and the physiological-based cord clamping (PBCC) approach, with the infant's transitional status as key determinant of timing of cord clamping. This approach could result in optimal timing of cord clamping and has the potential to reduce major morbidities and mortality in preterm infants

Draft genome sequences of the onion center rot Pathogen Pantoea ananatis PA4 and maize brown stalk rot Pathogen P. ananatis BD442

Pantoea ananatis is an emerging phytopathogen that infects a broad spectrum of plant hosts. Here, we present the genomes of two South African isolates, P. ananatis PA4, which causes center rot of onion, and BD442, isolated from brown stalk rot of maize.The University of Pretoria, the National Research Foundation (NRF), the Forestry and Agricultural Biotechnology Institute (FABI), the Tree Protection Cooperative Programme (TPCP), the NRF/Department of Science and Technology Centre of Excellence in tree Health Biotechnology (CTHB), and the THRIP support program of the Department of Trade and Industry, South Africa.http://genomea.asm.orgam201

Cryptic diversity and ranavirus infection of a critically endangered Neotropical frog before and after population collapse

Mesoamerican amphibian declines in apparently pristine and protected habitats have been severe, especially at elevations above 500 m sea level and have been linked to emerging diseases and a changing climate. The Craugastor punctariolus species series of direct developing frogs is endemic to the region and used to be comprised of 33 species, seven of which have known populations at present. One of these, Craugastor ranoides, endemic to southern Nicaragua and Costa Rica, was historically found in cloud forest sites of Área de Conservación Guanacaste (ACG) in north-west Costa Rica and extended into dry forest sites 20 km distant. Here C. ranoides declined and disappeared from high elevation sites between the late 1980s and early 1990s, but populations persisted in the lowland dry forest. We compared the genetic richness and ranavirus infection status of C. ranoides from extant dry forest populations to historic museum specimens of now extinct ACG cloud forest populations using DNA sequence diversity at two mitochondrial loci and molecular screening for ranavirus. Extant dry forest populations of C. ranoides formed a monophyletic group which included historic specimens sampled at cloud forest sites. However, the extirpated ACG cloud forest population contained additional diversity: samples formed a divergent clade with unknown spatial distribution. Ranavirus was detected in both current and museum samples of C. ranoides and sequences from a 267-nucleotide region of the major capsid protein gene shared 100% sequence identity with one another and with Frog virus 3. Our findings document cryptic diversity within an endangered species that has demonstrated no recovery in cloud forests and raises questions about Ranavirus as a potential driver of amphibian decline in this system. The presence of the same C. ranoides clade within present day and historical samples suggests a potential for effective translocation and repopulation of extirpated cloud forest populations

Search for heavy neutrinos mixing with tau neutrinos

We report on a search for heavy neutrinos (\nus) produced in the decay D_s\to \tau \nus at the SPS proton target followed by the decay \nudecay in the NOMAD detector. Both decays are expected to occur if \nus is a component of $\nu_{\tau}$.\ From the analysis of the data collected during the 1996-1998 runs with $4.1\times10^{19}$ protons on target, a single candidate event consistent with background expectations was found. This allows to derive an upper limit on the mixing strength between the heavy neutrino and the tau neutrino in the \nus mass range from 10 to 190 $\rm MeV$. Windows between the SN1987a and Big Bang Nucleosynthesis lower limits and our result are still open for future experimental searches. The results obtained are used to constrain an interpretation of the time anomaly observed in the KARMEN1 detector.\Comment: 20 pages, 7 figures, a few comments adde

Towards Machine Wald

The past century has seen a steady increase in the need of estimating and predicting complex systems and making (possibly critical) decisions with limited information. Although computers have made possible the numerical evaluation of sophisticated statistical models, these models are still designed \emph{by humans} because there is currently no known recipe or algorithm for dividing the design of a statistical model into a sequence of arithmetic operations. Indeed enabling computers to \emph{think} as \emph{humans} have the ability to do when faced with uncertainty is challenging in several major ways: (1) Finding optimal statistical models remains to be formulated as a well posed problem when information on the system of interest is incomplete and comes in the form of a complex combination of sample data, partial knowledge of constitutive relations and a limited description of the distribution of input random variables. (2) The space of admissible scenarios along with the space of relevant information, assumptions, and/or beliefs, tend to be infinite dimensional, whereas calculus on a computer is necessarily discrete and finite. With this purpose, this paper explores the foundations of a rigorous framework for the scientific computation of optimal statistical estimators/models and reviews their connections with Decision Theory, Machine Learning, Bayesian Inference, Stochastic Optimization, Robust Optimization, Optimal Uncertainty Quantification and Information Based Complexity.Comment: 37 page

An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics

For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types

Comprehensive Pan-Genomic Characterization of Adrenocortical Carcinoma

SummaryWe describe a comprehensive genomic characterization of adrenocortical carcinoma (ACC). Using this dataset, we expand the catalogue of known ACC driver genes to include PRKAR1A, RPL22, TERF2, CCNE1, and NF1. Genome wide DNA copy-number analysis revealed frequent occurrence of massive DNA loss followed by whole-genome doubling (WGD), which was associated with aggressive clinical course, suggesting WGD is a hallmark of disease progression. Corroborating this hypothesis were increased TERT expression, decreased telomere length, and activation of cell-cycle programs. Integrated subtype analysis identified three ACC subtypes with distinct clinical outcome and molecular alterations which could be captured by a 68-CpG probe DNA-methylation signature, proposing a strategy for clinical stratification of patients based on molecular markers