893 research outputs found
Shade Promotes Phototropism through Phytochrome B-Controlled Auxin Production.
Phototropism is an asymmetric growth response enabling plants to optimally position their organs. In flowering plants, the phototropin (phot) blue light receptors are essential to detect light gradients. In etiolated seedlings, the phototropic response is enhanced by the red/far-red (R/FR)-sensing phytochromes (phy) with a predominant function of phyA. In this study, we analyzed the influence of the phytochromes on phototropism in green (de-etiolated) Arabidopsis seedlings. Our experiments in the laboratory and outdoors revealed that, in open environments (high R/FR ratio), phyB inhibits phototropism. In contrast, under foliar shade, where access to direct sunlight becomes important, the phototropic response was strong. phyB modulates phototropism, depending on the R/FR ratio, by controlling the activity of three basic-helix-loop-helix (bHLH) transcription factors of the PHYTOCHROME INTERACTING FACTORs (PIFs) family. Promotion of phototropism depends on PIF-mediated induction of several members of the YUCCA gene family, leading to auxin production in the cotyledons. Our study identifies PIFs and YUCCAs as novel molecular players promoting phototropism in photoautotrophic, but not etiolated, seedlings. Moreover, our findings reveal fundamental differences in the phytochrome-phototropism crosstalk in etiolated versus green seedlings. We propose that in natural conditions where the light environment is not homogeneous, the uncovered phytochrome-phototropin co-action is important for plants to adapt their growth strategy to optimize photosynthetic light capture
p53 suppresses type II endometrial carcinomas in mice and governs endometrial tumour aggressiveness in humans
Type II endometrial carcinomas are a highly aggressive group of tumour subtypes that are frequently associated with inactivation of the TP53 tumour suppressor gene. We show that mice with endometrium-specific deletion of Trp53 initially exhibited histological changes that are identical to known precursor lesions of type II endometrial carcinomas in humans and later developed carcinomas representing all type II subtypes. The mTORC1 signalling pathway was frequently activated in these precursor lesions and tumours, suggesting a genetic cooperation between this pathway and Trp53 deficiency in tumour initiation. Consistent with this idea, analyses of 521 human endometrial carcinomas identified frequent mTORC1 pathway activation in type I as well as type II endometrial carcinoma subtypes. mTORC1 pathway activation and p53 expression or mutation status each independently predicted poor patient survival. We suggest that molecular alterations in p53 and the mTORC1 pathway play different roles in the initiation of the different endometrial cancer subtypes, but that combined p53 inactivation and mTORC1 pathway activation are unifying pathogenic features among histologically diverse subtypes of late stage aggressive endometrial tumours
Flood retention in alpine catchments equipped with complex hydropower schemes - A case study of the upper Aare catchment in Switzerland
The simulation of run-off in alpine catchment areas is an important issue for the optimal operation of hydropower plants for normal flow conditions, but also during flood events. A semi-lumped numerical approach combines hydrological modelling and operation of hydraulic elements. It allows simulation of operating mode of complex storage hydropower plants and its impacts on the downstream river system for different scenarios. The modelling of the upper Aare catchment with the Oberhasli hydropower scheme in Switzerland is presented. The effect of the existing reservoirs and their management, taking into account preventive turbining, on flood routing in the Aare River upstream of Lake Brienz is presented for the 2005 and 1987 flood events. The enhancement project KWOplus, which contains a considerable increase of storage volume in the main reservoir as well as in turbining capacity, is estimated
Plan or React? Analysis of Adaptation Costs and Benefits Using Integrated Assessment Models
This report examines adaptation and mitigation within an integrated framework. Global and
regional costs of adaptation are assessed dynamically and the resulting benefits are quantified.
This is accomplished by developing a framework to incorporate adaptation as a policy variable
within three Integrated Assessment Models (IAMs); the global Dynamic Integrated model of
Climate and the Economy (DICE), the Regional Integrated model of Climate and the Economy
(RICE), and the World Induced Technical Change Hybrid (WITCH) model. The framework
developed here takes into account investments in reactive adaptation and in adaptation âstocksâ,
as well as investments in building adaptive capacity. This report presents the first inter-model
comparison of results on adaptation costs using the emerging category of adaptation-IAMs.
Results show that least-cost policy response to climate change will need to involve subsantial
amounts of mitigation efforts, investments in adaptation stock, reactive adaptation measures and
adaptive capacity to limit the remaining damages
Single-cell proteomics defines the cellular heterogeneity of localized prostate cancer
Localized prostate cancer exhibits multiple genomic alterations and heterogeneity at the proteomic level. Single-cell technologies capture important cell-to-cell variability responsible for heterogeneity in biomarker expression that may be overlooked when molecular alterations are based on bulk tissue samples. This study aims to identify prognostic biomarkers and describe the heterogeneity of prostate cancer and the associated microenvironment by simultaneously quantifying 36 proteins using single-cell mass cytometry analysis of over 1.6 million cells from 58 men with localized prostate cancer. We perform this task, using a high-dimensional clustering pipeline named Franken to describe subpopulations of immune, stromal, and prostate cells, including changes occurring in tumor tissues and high-grade disease that provide insights into the coordinated progression of prostate cancer. Our results further indicate that men with localized disease already harbor rare subpopulations that typically occur in castration-resistant and metastatic disease
Norovirus Transmission on Cruise Ship
We documented transmission by food and person-to-person contact; persistence of virus despite sanitization onboard, including introductions of new strains; and seeding of an outbreak on land
Fusion of Optical Flow and Inertial Measurements for Robust Egomotion Estimation
In this paper we present a method for fusing optical flow and inertial measurements. To this end, we derive a novel visual error term which is better suited than the standard continuous epipolar constraint for extracting the information contained in the optical flow measurements. By means of an unscented Kalman filter (UKF), this information is then tightly coupled with inertial measurements in order to estimate the egomotion of the sensor setup. The individual visual landmark positions are not part of the filter state anymore. Thus, the dimensionality of the state space is significantly reduced, allowing for a fast online implementation. A nonlinear observability analysis is provided and supports the proposed method from a theoretical side. The filter is evaluated on real data together with ground truth from a motion capture system
Norwalk-like viral gastroenteritis outbreak in U.S. Army trainees.
An outbreak of acute gastroenteritis hospitalized 99 (12%) of 835 U. S. Army trainees at Fort Bliss, El Paso, Texas, from August 27 to September 1, 1998. Reverse transcriptase polymerase chain reaction tests for Norwalk-like virus were positive for genogroup 2. Gastroenteritis was associated with one post dining facility and with soft drinks
Assessing the impact of ETS trading profit on emission abatements based on firm-level transactions
hp-adaptive Galerkin Time Stepping Methods for Nonlinear Initial Value Problems
This work is concerned with the derivation of an a posteriori error estimator for Galerkin approximations to nonlinear initial value problems with an emphasis on finite-time existence in the context of blow-up. The structure of the derived estimator leads naturally to the development of both h and hp versions of an adaptive algorithm designed to approximate the blow-up time. The adaptive algorithms are then applied in a series of numerical experiments, and the rate of convergence to the blow-up time is investigated
- âŠ