The objective of this paper is to present a radar-based quantitative precipitation estimation algorithm and assess its quality over the complex terrain of western Iceland. The proposed scheme deals ...with the treatment of beam blockage, anomalous propagation, vertical profile of reflectivity and includes a radar adjustment technique compensating for range, orographic effects and variations in the
Z
–
R
relationship. The quality of the estimated precipitation is remarkably enhanced after post-processing and in reasonably good agreement with what is known about the spatial distribution of precipitation in the studied area from both rain gauge observations and a gridded dataset derived from an orographic precipitation model. The results suggest that this methodology offers a credible solution to obtain an estimate of the distribution of precipitation in mountainous terrain and appears to be of practical value to meteorologists and hydrologists.
The integration of rare-earth doped optical fibers as part of fiber-based systems in space implies the development of waveguides tolerant to the radiation levels associated with the space missions. ...Erbium (Er)- or Ytterbium/Erbium (Yb/Er)-doped fibers have been shown to be very sensitive to ionizing radiations. Radiations lead to a strong increase of the fiber attenuation around the pump and amplified signal wavelengths. In this paper, we investigate by confocal luminescence microscopy the radiation-induced spectroscopic changes on prototype Yb- or Yb/Er-doped optical fibers. The set of tested fibers allows us to provide new insights into the relative influence of the P, Al doping on the radiation responses of their silica-based host matrix and on the transitions between the energy states of rare-earth ions.
Yellow‐legged gulls Larus michahellis from the Atlantic Iberian coast exhibit some phenotypic similarities with the herring gull L. argentatus from Western Europe. To assess this phenomenon and its ...possible origin, we compared Mediterranean yellow‐legged gulls, Atlantic Iberian yellow‐legged gulls and herring gulls for several phenotypic traits (morphology, plumage), and used genetic data to determine the evolutionary history of the Atlantic Iberian yellow‐legged gulls. Data from mitochondrial cytochrome b gene and microsatellite loci clearly indicate that Atlantic Iberian gulls are closely related to Mediterranean yellow‐legged gulls, and do not show stronger signs of introgression with herring gulls relative to other populations of yellow‐legged gulls. Atlantic Iberian yellow‐legged gulls are more similar to herring gulls in body size and shape than to other yellow‐legged gulls populations, but not in mantle colour and wing‐tip pattern. Body size and other phenotypic and life history similarities with the herring gull (L. argentatus argenteus) such as voice, winter plumage and breeding phenology, previously described in several studies, might thus be interpreted as convergent characters. Within the yellow‐legged gull, the high Fst‐values obtained from four nuclear microsatellite loci indicate substantial population structure and reduced levels of gene flow between gull populations in Mediterranean France and Atlantic Iberia. Differences among these populations in breeding phenology and migration patterns, likely resulting from different local selection pressures, might contribute to this low level of gene flow.
Résumé
Les goélands à pattes jaunes (Larus michahellis) du littoral atlantique ibérique partagent plusieurs similarités phénotypiques avec le Goéland argenté (Larus argentatus) nichant plus au nord en Europe de l'Ouest. Afin d’évaluer prècisément ce phénomène et d'en comprendre l'origine, nous avons comparé les caractères phénotypiques (morphologie, plumage) des goélands à pattes jaunes de la côte atlantique ibérique avec ceux du Goéland leucophée méditerranéen (Larus michahellis) et du Goéland argenté. Par ailleurs, nous avons utilisé des marqueurs génétiques pour déterminer l'histoire évolutive des goélands à pattes jaunes du littoral atlantique ibérique. Les résultats obtenus à partir de l'ADN mitochondrial et de quatre microsatellites indiquent clairement que les goélands à pattes jaunes ibériques de l'atlantique sont fortement apparentés au Goéland leucophée et qu'il n'existe pas de signes récents d'introgression avec le Goéland argenté. Les goélands à pattes jaunes ibériques ressemblent davantage au Goéland argenté qu'au Goéland leucophée pour la taille et la forme corporelles mais pas pour ce qui est des patrons alaires ni de la couleur du manteau. Outre la taille corporelle, les similarités phénotypiques (voix, plumage hivernal) et des traits d'histoire de vie (phénologie de la reproduction, patrons de dispersion), déjà décrites dans la littérature, résultent donc probablement d'un phénomène de convergence. Au sein des goélands à pattes jaunes, les valeurs élevées de Fst obtenues avec les marqueurs microsatellites révèlent une forte structuration génétique des populations et indiquent un flux de gènes réduit entre les populations méditerranéennes et atlantiques. Les différences de phénologie de la reproduction et de patrons de migration entre ces populations résultant probablement de pressions de sélection locales différentes pourraient contribuer à ce faible flux de gènes.
We used DNA sequence data of the mitochondrial control region and cytochrome b gene to assess phylogenetic relationships among 32 gull species and two outgroup representatives. We tentatively ...estimated divergence times from transversional substitutions calibrated against DNA–DNA hybridization data. Several strongly supported species groups are identified, but the relationships between these species groups and the rooting of the gull tree remain unresolved. Geographical range extension appears as a factor of speciation, but several related, well‐differentiated species seem to have evolved within comparatively restricted areas. Some plumage characters used in the past for delimiting species groups appear inappropriate. The dark hooded species, for instance, do not constitute a natural assemblage. Molecular data also allowed the identification of several striking plumage convergences that had obscured the true relationships between gull species until now. For example, the dark tropical gulls analysed here each belong to totally different clades and are independent examples of convergent plumage evolution under common environmental constraints. The reverse situation also happened, with two arctic‐distributed species, the ivory gull (Pagophila eburnea) and the Sabine’s gull (Xema sabini), appearing as sister taxa despite completely different plumage features. Molecular data have thus significantly improved our understanding of gull evolution.
The climatic variability and trends of precipitation in Iceland are examined for the period 1961–2000 using bias-corrected rain gauge data and precipitation forecasts from the 40-yr ECMWF Re-Analysis ...(ERA-40). Several quantities are studied: the monthly and annual precipitation amounts as well as the statistical characteristics of 12-hourly precipitation rate and the geometrical features of the precipitation fields. The study highlights the credibility of ERA-40 and its ability to capture in a realistic manner the climatic variability of precipitation in Iceland, despite local discrepancies related to the crude horizontal resolution of these data. The observed intra- and interannual variations in the precipitation characteristics can be linked to variations in size, location, and occurrence of the large-scale precipitation systems crossing Iceland that are in turn influenced by the strength of the North Atlantic Oscillation, especially in winter.
A golden age for heavy-quarkonium physics dawned a decade ago, initiated by the confluence of exciting advances in quantum chromodynamics (QCD) and an explosion of related experimental activity. The ...early years of this period were chronicled in the Quarkonium Working Group (QWG) CERN Yellow Report (YR) in 2004, which presented a comprehensive review of the status of the field at that time and provided specific recommendations for further progress. However, the broad spectrum of subsequent breakthroughs, surprises, and continuing puzzles could only be partially anticipated. Since the release of the YR, the BESII program concluded only to give birth to BESIII; the
B
-factories and CLEO-c flourished; quarkonium production and polarization measurements at HERA and the Tevatron matured; and heavy-ion collisions at RHIC have opened a window on the deconfinement regime. All these experiments leave legacies of quality, precision, and unsolved mysteries for quarkonium physics, and therefore beg for continuing investigations at BESIII, the LHC, RHIC, FAIR, the Super Flavor and/or Tau–Charm factories, JLab, the ILC, and beyond. The list of newly found conventional states expanded to include
h
c
(1
P
),
χ
c
2
(2
P
),
, and
η
b
(1
S
). In addition, the unexpected and still-fascinating
X
(3872) has been joined by more than a dozen other charmonium- and bottomonium-like “
XYZ
” states that appear to lie outside the quark model. Many of these still need experimental confirmation. The plethora of new states unleashed a flood of theoretical investigations into new forms of matter such as quark–gluon hybrids, mesonic molecules, and tetraquarks. Measurements of the spectroscopy, decays, production, and in-medium behavior of
,
, and
bound states have been shown to validate some theoretical approaches to QCD and highlight lack of quantitative success for others. Lattice QCD has grown from a tool with computational possibilities to an industrial-strength effort now dependent more on insight and innovation than pure computational power. New effective field theories for the description of quarkonium in different regimes have been developed and brought to a high degree of sophistication, thus enabling precise and solid theoretical predictions. Many expected decays and transitions have either been measured with precision or for the first time, but the confusing patterns of decays, both above and below open-flavor thresholds, endure and have deepened. The intriguing details of quarkonium suppression in heavy-ion collisions that have emerged from RHIC have elevated the importance of separating hot- and cold-nuclear-matter effects in quark–gluon plasma studies. This review systematically addresses all these matters and concludes by prioritizing directions for ongoing and future efforts.
The signals in high mass dilepton spectroscopy with nucleus–nucleus collisions at collider energies are superimposed on a generally large combinatorial background. Because this background contains a ...significant correlated like-sign component originating from B meson decays, the “like-sign” method to determine the background is inappropriate. We discuss strategies to deal with the correlations in the background. By taking advantage of the B meson oscillation mechanism and of the particular features of B meson decays a new method to measure the
b
b
̄
production cross-section is proposed.
Display omitted
•First comprehensive phylogeny of Alaudidae (all genera, 83.5% of species).•Two mitochondrial, three nuclear loci (6.4kbp in total).•Unpredicted relationships, including ...non-monophyletic genera, revealed.•Revised generic classification, and comments on some species limits.•Extraordinary morphological divergence/convergence has disguised relationships.
The Alaudidae (larks) is a large family of songbirds in the superfamily Sylvioidea. Larks are cosmopolitan, although species-level diversity is by far largest in Africa, followed by Eurasia, whereas Australasia and the New World have only one species each. The present study is the first comprehensive phylogeny of the Alaudidae. It includes 83.5% of all species and representatives from all recognised genera, and was based on two mitochondrial and three nuclear loci (in total 6.4kbp, although not all loci were available for all species). In addition, a larger sample, comprising several subspecies of some polytypic species was analysed for one of the mitochondrial loci. There was generally good agreement in trees inferred from different loci, although some strongly supported incongruences were noted. The tree based on the concatenated multilocus data was overall well resolved and well supported by the data. We stress the importance of performing single gene as well as combined data analyses, as the latter may obscure significant incongruence behind strong nodal support values. The multilocus tree revealed many unpredicted relationships, including some non-monophyletic genera (Calandrella, Mirafra, Melanocorypha, Spizocorys). The tree based on the extended mitochondrial data set revealed several unexpected deep divergences between taxa presently treated as conspecific (e.g. within Ammomanes cinctura, Ammomanes deserti, Calandrella brachydactyla, Eremophila alpestris), as well as some shallow splits between currently recognised species (e.g. Certhilauda brevirostris–C. semitorquata–C. curvirostris; Calendulauda barlowi–C. erythrochlamys; Mirafra cantillans–M. javanica). Based on our results, we propose a revised generic classification, and comment on some species limits. We also comment on the extraordinary morphological adaptability in larks, which has resulted in numerous examples of parallel evolution (e.g. in Melanocorypha mongolica and Alauda leucoptera both usually placed in Melanocorypha; Ammomanopsis grayi and Ammomanes cinctura/deserti former traditionally placed in Ammomanes; Chersophilus duponti and Certhilauda spp.; Eremopterix hova usually placed in Mirafra and several Mirafra spp.), as well as both highly conserved plumages (e.g. within Mirafra) and strongly divergent lineages (e.g. Eremopterix hova vs. other Eremopterix spp.; Calandrella cinerea complex vs. Eremophila spp.; Eremalauda dunni vs. Chersophilus duponti; Melanocorypha mongolica and male M. yeltoniensis vs. other Melanocorypha spp. and female M. yeltoniensis). Sexual plumage dimorphism has evolved multiple times. Few groups of birds show the same level of disagreement between taxonomy based on morphology and phylogenetic relationships as inferred from DNA sequences.
Why and how new migration routes emerge remain fundamental questions in ecology, particularly in the context of current global changes. In its early stages, when few individuals are involved, the ...evolution of new migration routes can be easily confused with vagrancy, i.e. the occurrence of individuals outside their regular breeding, non-breeding or migratory distribution ranges. Yet, vagrancy can in theory generate new migration routes if vagrants survive, return to their breeding grounds and transfer their new migration route to their offspring, thus increasing a new migratory phenotype in the population. Here, we review the conceptual framework and empirical challenges of distinguishing regular migration from vagrancy in small obligate migratory passerines and explain how this can inform our understanding of migration evolution. For this purpose, we use the Yellow-browed Warbler (Phylloscopus inornatus) as a case study. This Siberian species normally winters in southern Asia and its recent increase in occurrence in Western Europe has become a prominent evolutionary puzzle. We first review and discuss available evidence suggesting that the species is still mostly a vagrant in Western Europe but might be establishing a new migration route initiated by vagrants. We then list possible empirical approaches to check if some individuals really undertake regular migratory movements between Western Europe and Siberia, which would make this species an ideal model for studying the links between vagrancy and the emergence of new migratory routes.
To report the frequency of caval occlusion after Vena Tech-LGM filter placement and identify related factors and their potential clinical significance.
The filter was inserted into 243 patients, 142 ...of whom met inclusion criteria for this prospective study. Follow-up examinations performed every 2 years included clinical evaluation, plain frontal radiography of the abdomen, duplex scanning of the inferior vena cava (IVC), and/or phlebocavography.
A progressive decrease in IVC patency was observed, reaching 66.8% at 9 years of follow-up. Complete caval occlusion occurred in 28 patients and was significantly (P < 10(-6)) associated with retraction in 24 cases. Caval occlusion was not related to age, sex, pulmonary embolism (PE), deep venous thrombosis level, underlying conditions predisposing to a thromboembolic disease before filter insertion, the level of filter placement, use of anticoagulant therapy, and death during follow-up. PE with anticoagulation failure was a predictive factor (P = .016) of subsequent filter occlusion during follow-up as compared to all other clinical indications for filter placement. Filter patency at 9 years of follow-up was 35.2% in the PE group with anticoagulation failure and 80% for other patients (odds ratio, 2.5; 95% confidence interval 1.16-5.4).
PE with anticoagulation failure was the only factor predictive of subsequent caval occlusion observed in patients after Vena Tech-LGM filter placement. Caval occlusion was also related to Vena Tech-LGM filter retraction, which usually occurred at the time of occlusion.
PDF
