163 research outputs found

    Towards understanding the Paleocean

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    A comparison is made between some of the framework used to discuss Paleoceanography and parallel situations in modern physical oceanography. A main inference is that too often the paleo literature aims to rationalize why a particular hypothesis remains appropriate, rather than undertaking to deliberately test that hypothesis.National Science Foundation (U.S.) (Grant No. OCE-0645936

    Submarine groundwater discharge and associated chemical input to a coastal sea

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    This paper presents a theoretical model of flow and chemical transport processes in subterranean estuaries (unconfined brackish groundwater aquifers at the ocean-land interface). The model shows that groundwater circulation and oscillating flow, caused by wave setup and tide, may constitute up to 96% of submarine groundwater discharge (SGWD) compared with 4% due to the net groundwater discharge. While these local flow processes do not change the total amount of land-derived chemical input to the ocean over a long period (e.g., yearly), they induce fluctuations of the chemical transfer rate as the aquifer undergoes saltwater intrusion. This may result in a substantial increase in chemical fluxes to the ocean over a short period (e.g., monthly and by a factor of 20 above the averaged level), imposing a possible threat to the marine environment. These results are essentially consistent with the experimental findings of Moore [1996] and have important implications for coastal resources management

    Neuregulin-1β, Biomarkers of Inflammation and Myocardial Fibrosis in Heart Failure Patients

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    Neuregulin-1β (NRG-1) is an emerging biomarker of heart failure (HF). The mechanisms of its action in HF patients are yet  to be investigated. Cardioprotective and anti-inflammatory  effects of NRG-1 have been reported.Aim. To assess NRG-1 levels in HF patients and investigate the association between NRG-1 and biomarkers of inflammation and myocardial fibrosis.Material and Methods. NRG-1, biomarkers of inflammation and fibrosis (hsCRP, IL-6, sVCAM-1, MMP-9, Galectin-3, ST2, TGF-β) were assessed in 47 patients with HF and preserved ejection fraction (HFpEF); 39 patients with HF and reduced ejection  (HFrEF) and 40 healthy participants. The associations between  NRG-1 and biomarkers of inflammation and fibrosis, as well as  the composite outcomes of cardiovascular death and HF  hospitalisations were assessed.Results. Median NRG-1 levels in HFpEF were 0.969 (0.348; 1.932) ng/ml, in HFrEF – 0.63 (0.348; 1.932), in healthy participants 0.379 (0.195; 0.861) ng/ml, and was significantly higher in HFpEF compared to healthy volunteers (р=0.004). There was no  difference in NRG-1 concentration between HFpEF and HFrEF. In  HF patients, all biomarkers of inflammation and fibrosis were  higher than in controls. ST2, IL-6 and TGF-β were significantly higher in HFrEF compared to HFpEF patients, while hsCRP,  sVCAM-1, MMP-9, and Galectin-3 levels were comparable. In  HFpEF, NRG-1 was associated with hsCRP (rs=0.378, p=0.023) and IL-6 (rs=0.378, p=0.014). Median follow-up time in patients with HFpEF and in patients was 312 (236; 388) days, in HFrEF – 147 (98; 237) days. In HFpEF, 2 patients died and 19 were  hospitalized due to HF. In HFrEF, 10 deaths and 19  hospitalizations were registered. Kaplan-Mayer analysis showed that HFpEF patients with increased NRG-1 and IL-6 had higher  levels of HF hospitalisation (log rank test, р=0.046 and р=0.012, respectively). In a multivariable cox proportional hazard model,  the association between the NRG-1 and outcomes remained significant after adjustment for age, gender and NTproBNP but diminished when hsCRP and IL-6 were included in the model.Conclusion. NGR-1 level significantly higher in HFpEF compared to healthy participants, and comparable with NRG-1 concentrations in HFrEF. In HFpEF, NRG-1 was associated with biomarkers of inflammation and fibrosis. The prognostic value of NRG-1 in HF requires further investigations

    Aromatic Amino Acids: Phenylalanine and Tyrosine in Patients with Hypertension and Coronary Artery Disease

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    Aim. To evaluate changes in the profile of aromatic amino acids (AAA) in patients with cardiovascular diseases (CVD): hypertension and coronary artery disease (CАD) in comparison with healthy study participants.Material and methods. One hundred and thirty-one participants were included in the study: 58 participants were included in the hypertension group, 46 in the CАD group, and 27 participants without signs of CVD in the control group. We used ultrahigh-performance liquid chromatography in combination with a triple quadrupole analyzer to measure plasma AAA: phenylalanine and tyrosine (Phe, Tyr) in all study participants. The association of AAA with biochemical blood test parameters, echocardiography (EchoCG) parameters, blood pressure level and clinical characteristics was analyzed.Results. A statistically significant difference in the level of concentration of Phe and Tyr was revealed (p=0,002 and p=0,024, respectively), comparing the three groups. Post-hoc analysis showed differences in the circulating level of both amino acids in patients with CAD vs the control group (Phe p=0,008 and Tyr p=0,020). Also a statistically significant difference in the level of Phe of the hypertension and CАD groups (p=0,017) was found. A negative correlation of low-density lipoproteins (LDL) with the level of Phe (r=-0,685, p<0,05) and Tyr (r=-0,583, p<0,05), as well as the level of Phe with total cholesterol (r=-0,461, p<0,05) was found in the group without CVD. In the hypertension group, only a weak positive correlation was found between very low-density lipoproteins and AAA levels (Phe r=0,326 and Tyr r=0,365, p<0,05), while in patients with CAD, the level of Phe and Tyr was negative correlated with high-density lipoprotein (r=-0,378 and r=-0,543, respectively, p<0,05), and the level of Tyr with LDL (r=0,349, p<0,05). When isolating the group with proven atherosclerosis of peripheral and/or coronary arteries, a statistically significant difference was revealed between the group of patients with CVD and clinical and instrumental signs of atherosclerosis and the group of patients with CVD without proven atherosclerosis in Phe level (p=0,019).Conclusion. Concentrations of AAA were higher in patients with CVD, comparing with the control group. At the same time, an increase of the Phe level was associated with the presence of peripheral or coronary atherosclerosis. The revealed correlations of AAA with EchoCG parameters and lipid spectrum parameters require further study to understand the involvement of AAA in pathogenesis of CVD and its potential role as treatment target

    Is the water footprint an appropriate tool for forestry and forest products: The Fennoscandian case

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    The water footprint by the Water Footprint Network (WF) is an ambitious tool for measuring human appropriation and promoting sustainable use of fresh water. Using recent case studies and examples from water-abundant Fennoscandia, we consider whether it is an appropriate tool for evaluating the water use of forestry and forest-based products. We show that aggregating catchment level water consumption over a product life cycle does not consider fresh water as a renewable resource and is inconsistent with the principles of the hydrologic cycle. Currently, the WF assumes that all evapotranspiration (ET) from forests is a human appropriation of water although ET from managed forests in Fennoscandia is indistinguishable from that of unmanaged forests. We suggest that ET should not be included in the water footprint of rain-fed forestry and forest-based products. Tools for sustainable water management should always contextualize water use and water impacts with local water availability and environmental sensitivity

    Linking Climate Change and Groundwater

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