Are invasive marsh frogs (Pelophylax ridibundus) replacing the native P. lessonae /P. esculentus hybridogenetic complex in Western Europe? Genetic evidence from a field study.

The water-frog L-E system, widespread in Western Europe, comprises the pool frog Pelophylax lessonae and the hybridogenetic edible frog P. esculentus, which originated from hybridization between pool frogs and marsh frogs (P. ridibundus). In P. esculentus, the lessonae (L) genome is eliminated during meiosis and has to be gained anew each generation from a P. lessonae partner, while the ridibundus (R') genome is transmitted clonally. It therefore accumulates deleterious mutations, so that R'R' offspring from P. esculentus x P. esculentus crosses are normally unviable. This system is now threatened by invasive P. ridibundus (RR) imported from Eastern Europe and the Balkans. We investigated the genetic interactions between invasive marsh frogs and native water frogs in a Swiss wetland area, and used genetic data collected in the field to validate several components of a recently postulated mechanism of species replacement. We identified neo-ridibundus individuals derived from crosses between invasive ridibundus and native esculentus, as well as newly arisen hybridogenetic esculentus lineages stemming from crosses between invasive ridibundus (RR) and native lessonae (LL). As their ridibundus genomes are likely to carry less deleterious mutations, such lineages are expected to produce viable ridibundus offspring, contributing to species replacement. However, such crosses with invasive ridibundus only occurred at a limited scale; moreover, RR x LL crosses did not induce any introgression from the ridibundus to the lessonae genome. We did not find any ridibundus stemming from crosses between ancient esculentus lineages. Despite several decades of presence on the site, introduced ridibundus individuals only represent 15% of sampled frogs, and their spatial distribution seems shaped by specific ecological requirements rather than history of colonization. We therefore expect the three taxa to coexist stably in this area.

Brain Tissue Hypoxia is a Strong Predictor of Outcome after Severe Traumatic Brain Injury Independent from Elevated Intracranial Pressure

Introduction: Low brain tissue oxygen pressure (PbtO2) is associated with worse outcome in patients with severe traumatic brain injury (TBI). However, it is unclear whether brain tissue hypoxia is merely a marker of injury severity or a predictor of prognosis, independent from intracranial pressure (ICP) and injury severity. Hypothesis: We hypothesized that brain tissue hypoxia was an independent predictor of outcome in patients wih severe TBI, irrespective of elevated ICP and of the severity of cerebral and systemic injury. Methods: This observational study was conducted at the Neurological ICU, Hospital of the University of Pennsylvania, an academic level I trauma center. Patients admitted with severe TBI who had PbtO2 and ICP monitoring were included in the study. PbtO2, ICP, mean arterial pressure (MAP) and cerebral perfusion pressure (CPP = MAP-ICP) were monitored continuously and recorded prospectively every 30 min. Using linear interpolation, duration and cumulative dose (area under the curve, AUC) of brain tissue hypoxia (PbtO2 < 15 mm Hg), elevated ICP >20 mm Hg and low CPP <60 mm Hg were calculated, and the association with outcome at hospital discharge, dichotomized as good (Glasgow Outcome Score [GOS] 4-5) vs. poor (GOS 1-3), was analyzed. Results: A total of 103 consecutive patients, monitored for an average of 5 days, was studied. Brain tissue hypoxia was observed in 66 (64%) patients despite ICP was < 20 mm Hg and CPP > 60 mm Hg (72 +/- 39% and 49 +/- 41% of brain hypoxic time, respectively). Compared with patients with good outcome, those with poor outcome had a longer duration of brain hypoxia (1.7 +/- 3.7 vs. 8.3 +/- 15.9 hrs, P<0.01), as well as a longer duration (11.5 +/- 16.5 vs. 21.6 +/- 29.6 hrs, P=0.03) and a greater cumulative dose (56 +/- 93 vs. 143 +/- 218 mm Hg*hrs, P<0.01) of elevated ICP. By multivariable logistic regression, admission Glasgow Coma Scale (OR, 0.83, 95% CI: 0.70-0.99, P=0.04), Marshall CT score (OR 2.42, 95% CI: 1.42-4.11, P<0.01), APACHE II (OR 1.20, 95% CI: 1.03-1.43, P=0.03), and the duration of brain tissue hypoxia (OR 1.13; 95% CI: 1.01-1.27; P=0.04) were all significantly associated with poor outcome. No independent association was found between the AUC for elevated ICP and outcome (OR 1.01, 95% CI 0.97-1.02, P=0.11) in our prospective cohort. Conclusions: In patients with severe TBI, brain tissue hypoxia is frequent, despite normal ICP and CPP, and is associated with poor outcome, independent of intracranial hypertension and the severity of cerebral and systemic injury. Our findings indicate that PbtO2 is a strong physiologic prognostic marker after TBI. Further study is warranted to examine whether PbtO2-directed therapy improves outcome in severely head-injured patients .

Does wheat genetically modified for disease resistance affect root-colonizing pseudomonads and arbuscular mycorrhizal fungi?

This study aimed to evaluate the impact of genetically modified (GM) wheat with introduced pm3b mildew resistance transgene, on two types of root-colonizing microorganisms, namely pseudomonads and arbuscular mycorrhizal fungi (AMF). Our investigations were carried out in field trials over three field seasons and at two locations. Serial dilution in selective King's B medium and microscopy were used to assess the abundance of cultivable pseudomonads and AMF, respectively. We developed a denaturing gradient gel electrophoresis (DGGE) method to characterize the diversity of the pqqC gene, which is involved in Pseudomonas phosphate solubilization. A major result was that in the first field season Pseudomonas abundances and diversity on roots of GM pm3b lines, but also on non-GM sister lines were different from those of the parental lines and conventional wheat cultivars. This indicates a strong effect of the procedures by which these plants were created, as GM and sister lines were generated via tissue cultures and propagated in the greenhouse. Moreover, Pseudomonas population sizes and DGGE profiles varied considerably between individual GM lines with different genomic locations of the pm3b transgene. At individual time points, differences in Pseudomonas and AMF accumulation between GM and control lines were detected, but they were not consistent and much less pronounced than differences detected between young and old plants, different conventional wheat cultivars or at different locations and field seasons. Thus, we conclude that impacts of GM wheat on plant-beneficial root-colonizing microorganisms are minor and not of ecological importance. The cultivation-independent pqqC-DGGE approach proved to be a useful tool for monitoring the dynamics of Pseudomonas populations in a wheat field and even sensitive enough for detecting population responses to altered plant physiology.

Radio detections towards unidentified variable EGRET sources

A considerable fraction of the -ray sources discovered with the Energetic Gamma-Ray Experiment Telescope (EGRET) remain unidentified. The EGRET sources that have been properly identified are either pulsars or variable sources at both radio and gamma-ray wavelengths. Most of the variable sources are strong radio blazars. However, some low galactic-latitude EGRET sources, with highly variable -ray emission, lack any evident counterpart according to the radio data available until now. Aims. The primary goal of this paper is to identify and characterise the potential radio counterparts of four highly variable -ray sources in the galactic plane through mapping the radio surroundings of the EGRET confidence contours and determining the variable radio sources in the field whenever possible. Methods. We have carried out a radio exploration of the fields of the selected EGRET sources using the Giant Metrewave Radio Telescope (GMRT) interferometer at 21 cm wavelength, with pointings being separated by months. Results. We detected a total of 151 radio sources. Among them, we identified a few radio sources whose flux density has apparently changed on timescales of months. Despite the limitations of our search, their possible variability makes these objects a top-priority target for multiwavelength studies of the potential counterparts of highly variable, unidentified gamma-ray sources.

Seasonal occurrence of Lygus bugs on field crops in Finland

Selostus: Niittyluteiden esiintyminen viljelykasveissa kasvukauden eri aikoina

The central Sesia-Lanzo zone (Western Italian Alps) - New field observations and lithostratigraphic subdivisions

An extensive study of the central part of the Sesia Lanzo Zone has been undertaken to identify pre-Alpine protoliths and to reconstruct the lithologic and tectonic setting of this part of the Western Alps. Three main complexes have been defined: 1) the Polymetamorphic Basement Complex, corresponding to the lower unit of the Sesia Lanzo Zone after COMPAGNONI et al. (1977), is further subdivided into the three following units: a) an Internal Unit characterized by eo-Alpine high pressure (HP) assemblages (DAL PIAZ et al., 1972) (Eclogitic Micaschists); b) an Intermediate Unit where HP parageneses are partially re-equilibrated under greenschist conditions and c) an External Unit where the main foliation is defined by a greenschist paragenesis (Gneiss Minuti auct.). 2) the Monometamorphic Cover Complex, subdivided into the followings: a) the Bonze Unit, composed of sheared metagabbros, eclogitized metabasalts with MORB geochemical affinity and related metasediments (micaschists, quartzites and Mn-cherts) and b) the Scalaro Unit, containing predominantly metasediments of supposed Permo-Triassic age (yellow dolomitic marbles, calcschists and conglomeratic limestones, micaschists and quartzites with thin levels of basic rocks with within plate basalts [WPB] geochimical affinity). Multiple lithostratigraphic sequences for the Monometamorphic Cover Complex are proposed. The contact between the Bonze and Scalaro Units is defined by repetitions of dolomitic marbles and metabasalts; the ages of the metasediments have been assigned solely by analogy with other sediments of the Western Alps, due to the absence of fossils. The Monometamorphic Cover Complex can be considered as the autochthonous cover of the Sesia Lanzo Zone because of the primary contacts with the basement and because of the presence of preAlpine HT basement blocks in the cover sequences. 3) The pre-Alpine high temperature (HT) Basement Complex (or `'Seconda Zona Diorito-Kinzigitica''), comprises HT Hercynian rocks like kinzigites, amphibolites, granulites and calcite marbles; this Complex is always located between the Internal and the External Units and can be followed continuously for several kilometers south of the Gressoney Valley to the Orco Valley. A schematic evolution for the Sesia Lanzo Zone is proposed; based on available data together with new geochronological data, this study shows that the internal and external parts of the polymetamorphic basement of the Sesia Zone experienced different cooling histories .

Long-term fertilizer field trials: comparison of three mathematical response models

Selostus: Lannoituksen pitkäaikaiset kenttäkokeet: kolmen matemaattisen mallin vertailu

Drought response of modern and old oat lines in greenhouse and long-term field trials

Selostus: Vanhojen ja uusien kauralajikkeiden reagointi kuivuuteen kasvihuone- ja peltokokeissa

Numerical analysis of wave-induced fluid flow effects on seismic data: Application to monitoring of CO2 storage at the Sleipner Field

In this work we analyze how patchy distributions of CO2 and brine within sand reservoirs may lead to significant attenuation and velocity dispersion effects, which in turn may have a profound impact on surface seismic data. The ultimate goal of this paper is to contribute to the understanding of these processes within the framework of the seismic monitoring of CO2 sequestration, a key strategy to mitigate global warming. We first carry out a Monte Carlo analysis to study the statistical behavior of attenuation and velocity dispersion of compressional waves traveling through rocks with properties similar to those at the Utsira Sand, Sleipner field, containing quasi-fractal patchy distributions of CO2 and brine. These results show that the mean patch size and CO2 saturation play key roles in the observed wave-induced fluid flow effects. The latter can be remarkably important when CO2 concentrations are low and mean patch sizes are relatively large. To analyze these effects on the corresponding surface seismic data, we perform numerical simulations of wave propagation considering reservoir models and CO2 accumulation patterns similar to the CO2 injection site in the Sleipner field. These numerical experiments suggest that wave-induced fluid flow effects may produce changes in the reservoir's seismic response, modifying significantly the main seismic attributes usually employed in the characterization of these environments. Consequently, the determination of the nature of the fluid distributions as well as the proper modeling of the seismic data constitute important aspects that should not be ignored in the seismic monitoring of CO2 sequestration problems.