100 research outputs found
Modeling of Atmospheric Transport and Deposition of Heavy Metals in the Katowice Province
A large part of Poland's heavy industry, notably hard coal mining, ferrous and nonferrous metallurgy and power generation, is located in the Katowice province. Therefore, this heavy industrialized region, which is populated by four million people, experiences considerable problems with air pollution. In the METKAT study launched by the International Institute for Applied Systems Analysis we attempt to model atmospheric depositions of arsenic (As), cadmium (Cd), lead (Pb) and zinc (Zn) which are among the highest in Europe.
The applied modeling approach consists of performing detailed simulations of atmospheric transport and deposition of heavy metals with horizontal grid spacing of 5 km within one 150x150 km cell of the EMEP grid covering the Katowice province. For this purpose we implemented the Lagrangian Particle Dispersion and Deposition (LPDD) model driven by two mesoscale/regional meteorological models. Preliminary deposition calculations for the entire 1992 year and a series of sensitivity experiments for cadmium were run using relatively simple but computationally efficient hydrostatic meteorological model (MESO). The deposition results from the MESO/LPDD modeling applied to the mesoscale domain were supplemented by contributions from other emission sources in Europe calculated with the aid of the Heavy Metals Eulerian Transport (HMET) model.
The performed sensitivity tests indicate that the calculated depositions depend primarily on the quality of emission data (magnitude, spatial distribution and aggregation). Also land use data seem to be relatively important when estimating the location and magnitude of peak depositions. The proposed modeling approach shows some potential to reproduce local maxima in the deposition fluxes of heavy metals which cannot be resolved by long range transport models. However, very high Cd deposition values observed in the region cannot be reproduced by the model with available emission inventory even when emission from selected sources was increased by two orders of magnitude. The model calculations do not take into account reemission of particulates from post-mining areas and waste dumps, which may contribute considerably to ambient concentrations. A receptor-oriented modeling approach based on an influence function concepts is proposed as a tool to further investigate contributions of different potential emission sources to the observed depositions.
A series of additional 24-hour simulations for idealized synoptic conditions were run with the LPDD model linked to the Colorado State University RAMS (Regional Atmospheric Modeling System). The purpose of these simulations was to investigate the potential effect of regional scale topography on mesoscale atmospheric transport within the Katowice province. Although the terrain of this province is not very complicated, the Sudeten and Carpathian Mountains surrounding this region from the south may significantly affect transport and deposition there
Thyroid metastases from a breast cancer diagnosed by fine-needle aspiration biopsy. Case report and overview of the literature
Aim: Intrathyroid metastases are uncommon in cytology practice. We report a case of metastatic lesion in the thyroid from breast carcinoma which was recognized in a fine-needle aspiration (FNA) biopsy and confirmed by immunohistopathology. In addition, we provide an overview of the literature describing similar cases. Study design: The patient was a 54-year old woman with a large, multinodular goiter and bilaterally enlarged lymph nodes in the supraclavicular areas. Fourteen years earlier she had undergone radical mastectomy followed by chemio- and radiotherapy due to a breast carcinoma. Results: FNA of the thyroid nodules showed a metastatic breast carcinoma and was followed by total strumectomy and lymphadenectomy. Histological reassessment of the surgical thyroid specimens as well as the neck lymph nodes revealed multiple breast metastases. This was strongly confirmed by immunohistochemical examinations, which revealed a positive staining for: CKMNF 116, CK7, CEA as well as for ER, PgR and HER2, and a negative staining for: CK20, thyroglobulin, TTF1, calcitonin, and chromogranin. Conclusion: Every new aggregate in the thyroid in patients with even a long-term history of cancer should be considered as potentially metastatic until proved otherwise. FNA could be helpful in the diagnosis of thyroid metastatic lesion, but it should be confirmed by immunohistopathology
Dephosphorylation of juxtamembrane serines and threonines of the NPR2 guanylyl cyclase is required for rapid resumption of oocyte meiosis in response to luteinizing hormone
AbstractThe meiotic cell cycle of mammalian oocytes starts during embryogenesis and then pauses until luteinizing hormone (LH) acts on the granulosa cells of the follicle surrounding the oocyte to restart the cell cycle. An essential event in this process is a decrease in cyclic GMP in the granulosa cells, and part of the cGMP decrease results from dephosphorylation and inactivation of the natriuretic peptide receptor 2 (NPR2) guanylyl cyclase, also known as guanylyl cyclase B. However, it is unknown whether NPR2 dephosphorylation is essential for LH-induced meiotic resumption. Here, we prevented NPR2 dephosphorylation by generating a mouse line in which the seven regulatory serines and threonines of NPR2 were changed to the phosphomimetic amino acid glutamate (Npr2–7E). Npr2–7E/7E follicles failed to show a decrease in enzyme activity in response to LH, and the cGMP decrease was attenuated; correspondingly, LH-induced meiotic resumption was delayed. Meiotic resumption in response to EGF receptor activation was likewise delayed, indicating that NPR2 dephosphorylation is a component of the pathway by which EGF receptor activation mediates LH signaling. We also found that most of the NPR2 protein in the follicle was present in the mural granulosa cells. These findings indicate that NPR2 dephosphorylation in the mural granulosa cells is essential for the normal progression of meiosis in response to LH and EGF receptor activation. In addition, these studies provide the first demonstration that a change in phosphorylation of a transmembrane guanylyl cyclase regulates a physiological process, a mechanism that may also control other developmental events
Carbon flux bias estimation employing Maximum Likelihood Ensemble Filter (MLEF)
We evaluate the capability of an ensemble based data assimilation approach, referred to as Maximum Likelihood Ensemble Filter (MLEF), to estimate biases in the CO2 photosynthesis and respiration fluxes. We employ an off-line Lagrangian Particle Dispersion Model (LPDM), which is driven by the carbon fluxes, obtained from the Simple Biosphere - Regional Atmospheric Modeling System (SiB-RAMS). The SiB-RAMS carbon fluxes are assumed to have errors in the form of multiplicative biases. Our goal is to estimate and reduce these biases and also to assign reliable posterior uncertainties to the estimated biases. Experiments of this study are performed using simulated CO2 observations, which resemble real CO2 concentrations from the Ring of Towers in northern Wisconsin. We evaluate the MLEF results with respect to the 'truth' and the Kalman Filter (KF) solution. The KF solution is considered theoretically optimal for the problem of this study, which is a linear data assimilation problem involving Gaussian errors. We also evaluate the impact of forecast error covariance localization based on a new 'distance' defined in the space of information measures. Experimental results are encouraging, indicating that the MLEF can successfully estimate carbon flux biases and their uncertainties. As expected, the estimated biases are closer to the 'true' biases in the experiments with more ensemble members and more observations. The data assimilation algorithm has a stable performance and converges smoothly to the KF solution when the ensemble size approaches the size of the model state vector (i.e., the control variable of the data assimilation problem
A Peer-reviewed Newspaper About_ Machine Feeling
On the ability of technologies to capture and structure feelings and experiences that are active, in flux, and situated in the present.
Publication resulting from research workshop at CRASSH, University of Cambridge, organised in collaboration with CRASSH, University of Cambridge and transmediale festival for art and digital culture, Berlin
Conversion of the Mycotoxin Patulin to the Less Toxic Desoxypatulinic Acid by the Biocontrol Yeast Rhodosporidium kratochvilovae Strain LS11
Se describe en este artículo el descubrimiento de la degradación de la micotoxina patulina por una levaduraThe infection of stored apples by the fungus Penicillium expansum causes the contamination of fruits and fruit-derived
products with the mycotoxin patulin, which is a major issue in food safety. Fungal attack can be prevented by beneficial
microorganisms, so-called biocontrol agents. Previous time-course thin layer chromatography analyses showed that the aerobic
incubation of patulin with the biocontrol yeast Rhodosporidium kratochvilovae strain LS11 leads to the disappearance of the
mycotoxin spot and the parallel emergence of two new spots, one of which disappears over time. In this work, we analyzed the
biodegradation of patulin effected by LS11 through HPLC. The more stable of the two compounds was purified and characterized by
nuclear magnetic resonance as desoxypatulinic acid, whose formation was also quantitated in patulin degradation experiments. After
R. kratochvilovae LS11 had been incubated in the presence of 13C-labeled patulin, label was traced to desoxypatulinic acid, thus
proving that this compound derives from the metabolization of patulin by the yeast. Desoxypatulinic acid was much less toxic than
patulin to human lymphocytes and, in contrast to patulin, did not react in vitro with the thiol-bearing tripeptide glutathione. The
lower toxicity of desoxypatulinic acid is proposed to be a consequence of the hydrolysis of the lactone ring and the loss of functional
groups that react with thiol groups. The formation of desoxypatulinic acid from patulin represents a novel biodegradation pathway
that is also a detoxification process
Bridging the gap between atmospheric concentrations and local ecosystem measurements
This paper demonstrates that atmospheric inversions of CO<sub>2</sub> are a reliable tool for estimating regional fluxes. We compare results of an inversion over 18 days and a 300 x 300 km 2 domain in southwest France against independent measurements of fluxes from aircraft and towers. The inversion used concentration measurements from 2 towers while the independent data included 27 aircraft transects and 5 flux towers. The inversion reduces the mismatch between prior and independent fluxes, improving both spatial and temporal structures. The present mesoscale atmospheric inversion improves by 30% the CO<sub>2</sub> fluxes over distances of few hundreds of km around the atmospheric measurement locations. Citation: Lauvaux, T., et al. (2009), Bridging the gap between atmospheric concentrations and local ecosystem measurements, Geophys. Res. Lett., 36, L19809, doi: 10.1029/2009GL039574
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