In 1997-98, fires associated with an exceptional drought caused by the El Niño/Southern Oscillation (ENSO) devastated large areas of tropical rain forests worldwide. Evidence suggests that in ...tropical rainforest environments selective logging may lead to an increased susceptibility of forests to fire. We investigated whether this was true in the Indonesian fires, the largest fire disaster ever observed. We performed a multiscale analysis using coarse- and high-resolution optical and radar satellite imagery assisted by ground and aerial surveys to assess the extent of the fire-damaged area and the effect on vegetation in East Kalimantan on the island of Borneo. A total of 5.2 ± 0.3 million hectares including 2.6 million hectares of forest was burned with varying degrees of damage. Forest fires primarily affected recently logged forests; primary forests or those logged long ago were less affected. These results support the hypothesis of positive feedback between logging and fire occurrence. The fires severely damaged the remaining forests and significantly increased the risk of recurrent fire disasters by leaving huge amounts of dead flammable wood.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Genomic rearrangements are thought to occur progressively during tumor development. Recent findings, however, suggest an alternative mechanism, involving massive chromosome rearrangements in a ...one-step catastrophic event termed chromothripsis. We report the whole-genome sequencing-based analysis of a Sonic-Hedgehog medulloblastoma (SHH-MB) brain tumor from a patient with a germline TP53 mutation (Li-Fraumeni syndrome), uncovering massive, complex chromosome rearrangements. Integrating TP53 status with microarray and deep sequencing-based DNA rearrangement data in additional patients reveals a striking association between TP53 mutation and chromothripsis in SHH-MBs. Analysis of additional tumor entities substantiates a link between TP53 mutation and chromothripsis, and indicates a context-specific role for p53 in catastrophic DNA rearrangements. Among these, we observed a strong association between somatic TP53 mutations and chromothripsis in acute myeloid leukemia. These findings connect p53 status and chromothripsis in specific tumor types, providing a genetic basis for understanding particularly aggressive subtypes of cancer.
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► Complex chromosomal alterations (chromothripsis) observed in medulloblastomas ► Cancers with such alterations harbor TP53 mutations ► Context-specific link between the status of p53 and likelihood of chromothripsis ► p53 status and chromothripsis also correlate with aggressive acute myeloid leukemia
Connecting p53 status and chromothripsis in specific types of cancer provides a genetic basis for the more aggressive forms of medulloblastoma and leukemia.
Current space-borne thermal infrared satellite systems aimed at land surface remote sensing retain some significant deficiencies, in particular in terms of spatial resolution, spectral coverage, ...number of imaging bands and temperature-emissivity separation. The proposed VISible-to-thermal IR micro-SATellite (VISIR-SAT) mission addresses many of these limitations, providing multi-spectral imaging data with medium-to-high spatial resolution (80m GSD from 800 km altitude) in the thermal infrared (up to 6 TIR bands, between 8 and 11μm) and in the mid infrared (1 or 2 MIR bands, at 4μm). These MIR/TIR bands will be co-registered with simultaneously acquired high spatial resolution (less than 30 m GSP) visible and near infrared multi-spectral imaging data. To enhance the spatial resolution of the MIR/TIR multi-spectral imagery during daytime, data fusion methods will be applied, such as the Multi-sensor Multi-resolution Technique (MMT), already successfully tested over agricultural terrain. This image processing technique will make generation of Land Surface Temperature (LST) EO products with a spatial resolution of 30 x 30 m2 possible. For high temperature phenomena such as vegetation- and peat-fires, the Fire Disturbance Essential Climate Variables (ECV) “Active fire location” and “Fire Radiative Power” will be retrieved with less than 100 m spatial resolution. Together with the effective fire temperature and the spatial extent even for small fire events the innovative system characteristics of VISIR-SAT go beyond existing and planned IR missions. The comprehensive and physically high-accuracy products from VISIR-SAT (e.g. for fire monitoring) may synergistically complement the high temperature observations of Sentinel-3 SLSTR in a unique way. Additionally, VISIR-SAT offers a very agile sensor system, which will be able to conduct intelligent and flexible pointing of the sensor’s line-of-sight with the aim to provide global coverage of cloud free imagery every 5–10 days with only one satellite (using near real time cloud cover information). VISIRSAT may be flown in convoy with Sentinel-3 and/or Sentinel-2.
Acute myeloid leukemia (AML) is characterized by molecular heterogeneity. As commonly altered genomic regions point to candidate genes involved in leukemogenesis, we used microarray-based comparative ...genomic hybridization and single nucleotide polymorphism profiling data of 391 AML cases to further narrow down genomic regions of interest. Targeted resequencing of 1000 genes located in the critical regions was performed in a representative cohort of 50 AML samples comprising all major cytogenetic subgroups. We identified 120 missense/nonsense mutations as well as 60 insertions/deletions affecting 73 different genes (∼ 3.6 tumor-specific aberrations/AML). While most of the newly identified alterations were nonrecurrent, we observed an enrichment of mutations affecting genes involved in epigenetic regulation including known candidates like TET2, TET1, DNMT3A, and DNMT1, as well as mutations in the histone methyltransferases NSD1, EZH2, and MLL3. Furthermore, we found mutations in the splicing factor SFPQ and in the nonclassic regulators of mRNA processing CTCF and RAD21. These splicing-related mutations affected 10% of AML patients in a mutually exclusive manner. In conclusion, we could identify a large number of alterations in genes involved in aberrant splicing and epigenetic regulation in genomic regions commonly altered in AML, highlighting their important role in the molecular pathogenesis of AML.
Haemoglobin (Hb) and Reticulocytes (Ret) are measured as indirect markers of doping in athletes. We studied the diurnal variation, the impact of exercise, fluid intake and ambient temperature in ...athletes on these parameters. Hourly venous blood samples were obtained from 36 male athletes of different disciplines (endurance (END) and non-endurance (NON-END)) over 12 h during a typical training day. Seven inactive subjects served as controls (CON). Hb and Ret were determined. A mixed model procedure was used to analyse the data. At baseline, Hb was similar for all groups, END showed lower Ret than NON-END and CON. Exercise showed a significant impact on Hb (+0.46 g/dl, p<0.001), the effect disappeared approximately 2 h after exercise. Hb decreased over the day by approximately 0.55 g/dl (p<0.01). There was no relevant effect on Ret. Fluid intake and ambient temperature had no significant effect. Hb shows significant diurnal- and exercise related variations. In an anti-doping context, most of these variations are in favour of the athlete. Blood samples taken after exercise might therefore provide reliable results and thus be used for the longitudinal monitoring of athletes if a timeframe for the re-equilibration of vascular volumes is respected.
IntroductionAccurate and complete reporting of information about trial participants is important to apply results in clinical practice. We studied whether and how eligibility criteria (EC) of ...participants of randomised trials pre-specified in study protocols are reported in subsequent articles.MethodsBy electronic literature searches and survey of applicants, we identified 78 full publications corresponding to 52 trial protocols submitted in 2000 to the ethics committee of the University of Freiburg/Germany. From both sources we extracted information on EC, whether they were matching, missing, modified or added in the publications.ResultsWe found differences between protocols and publications for all 52 trials. Information on EC was missing in publications corresponding to 52 trials (100%; 95% CI 93 to 100), modified for 44 trials (85%; 95% CI 72 to 93) or newly added for 21 trials (41%; 95% CI 27 to 55). The mean number of EC per trial was 25 (range 7–43); the mean proportion of matching EC per trial was 50% (range 13–93; 95% CI 44 to 55). Of 1248 EC pre-specified in protocols, 606 (49%) were matching, 479 (38%) missing, and 163 (13%) modified in subsequent publications. Fifty-one EC were added to publications. Most of the missing EC (96%) and about half of the modified EC (54%) suggested broader study populations, most added EC (86%) narrower study populations.ConclusionPublished trial reports generally do not reflect the definitions of study populations pre-specified in the protocol. This hampers a proper assessment of the applicability of trial results.
Summary
Background Dysregulation of the cyclic guanosine 3′,5′ monophosphate–nitric oxide system is in part responsible for portal hypertension in cirrhosis.
Aim To test the effects of inhibitors ...of phosphodiesterase‐5 on portal haemodynamics.
Methods To 18 healthy subjects and 18 patients with Child A liver cirrhosis, 10 mg of vardenafil, an inhibitor of phosphodiesterase‐5, were administered orally. Doppler sonographic measurements of hepatic and splanchnic blood flow, systemic blood pressure and heart rate were recorded before, 1 h after, and 48 h after the application. Vardenafil plasma levels were determined after 1 h. In five patients, invasive registration of free and wedged hepatic vein pressure was performed.
Results Portal venous flow increased in patients from 0.82 ± 0.30 L/min (mean ± s.d.) by 26% (CI: 16–37%, P = 0.0004) and in healthy subjects from 0.75 ± 0.20 L/min (mean ± s.d.) by 19% (CI: 9–28%; P = 0.0010). Celiac and hepatic artery resistivity indices rose significantly. Systemic blood pressure decreased slightly in patients. The wedged hepatic venous pressure gradient decreased in four of five patients with liver cirrhosis. Vardenafil plasma levels were higher in patients (14 ± 10 μg/L) than in healthy subjects (9 ± 6 μg/L; n.s.).
Conclusions Inhibition of phosphodiesterase‐5 increases portal flow and lowers portal pressure by a decrease in sinusoidal resistance and may be a novel therapeutic strategy for portal hypertension.
Systematic variations of soil properties occur along the hillslope due to differences in water and energy conditions. Such catenary soil variations are often assumed, in turn, to influence erosion ...processes, but quantitative investigations dealing with the reciprocal relationship between catenary soil development and erosion processes are limited. This study models the influence of catenary soil development on erosion processes on a hillslope in Uganda. The Water Erosion Prediction Project (WEPP)- model was selected to determine the impact of spatial distribution of soil types on hillslope soil loss. A detailed soil survey confirmed a well-developed catenary sequence at the study site. Soils at the summit position had a thick solum due to the stable soil formation on the flat surface, whereas soils at the shoulder position had shallow A-horizons due to active erosion processes. Valley and footslope soils showed hydromorphic features and accumulation of soil material from upslope. The performance of the WEPP- model was evaluated by a sensitivity analysis, which proved that the model was sensitive to vertical changes in soil properties to a depth of 40 cm. High sensitivity to soil texture indicated that the catenary sequence at the study site may have a strong influence on model simulations. When the hillslope was modelled as a uniform soil-landscape unit using each individual soil profile separately, simulated outputs showed high variations with annual soil loss ranging between 2.5 and 9 t/ha. This variation was reduced by including an increasing number of distinct soil-landscape units representative for the individual slope sections. Simulations considering a catenary soil sequence showed a clear spatial demarcation between erosion and sedimentation zones, which was verified by soil investigations. This implies that simulations including a higher number of soil-landscape units generate a more realistic spatial distribution of erosion–sedimentation processes at a hillslope.
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