103 research outputs found

    First assessment of the plant phenology index (PPI) for estimating gross primary productivity in African semi-arid ecosystems

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    The importance of semi-arid ecosystems in the global carbon cycle as sinks for CO2 emissions has recently been highlighted. Africa is a carbon sink and nearly half its area comprises arid and semi-arid ecosystems. However, there are uncertainties regarding CO2 fluxes for semi-arid ecosystems in Africa, particularly savannas and dry tropical woodlands. In order to improve on existing remote-sensing based methods for estimating carbon uptake across semi-arid Africa we applied and tested the recently developed plant phenology index (PPI). We developed a PPI-based model estimating gross primary productivity (GPP) that accounts for canopy water stress, and compared it against three other Earth observation-based GPP models: the temperature and greenness model, the greenness and radiation model and a light use efficiency model. The models were evaluated against in situ data from four semi-arid sites in Africa with varying tree canopy cover (3 to 65 percent). Evaluation results from the four GPP models showed reasonable agreement with in situ GPP measured from eddy covariance flux towers (EC GPP) based on coefficient of variation, root-mean-square error, and Bayesian information criterion. The PPI-based GPP model was able to capture the magnitude of EC GPP better than the other tested models. The results of this study show that a PPI-based GPP model is a promising tool for the estimation of GPP in the semi-arid ecosystems of Africa.Comment: Accepted manuscript; 12 pages, 4 tables, 9 figure

    High power impulse magnetron sputtering discharges: Instabilities and plasma self-organization

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    We report on instabilities in high power impulse magnetron sputtering plasmas which are likely to be of the generalized drift wave type. They are characterized by well defined regions of high and low plasma emissivity along the racetrack of the magnetron and cause periodic shifts in floating potential. The azimuthal mode number m depends on plasma current, plasma density, and gas pressure. The structures rotate in × direction at velocities of ∼10 km s−1 and frequencies up to 200 kHz. Collisions with residual gas atoms slow down the rotating wave, whereas increasing ionization degree of the gas and plasma conductivity speeds it up

    Boron Stress Responsive MicroRNAs and Their Targets in Barley

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    Boron stress is an environmental factor affecting plant development and production. Recently, microRNAs (miRNAs) have been found to be involved in several plant processes such as growth regulation and stress responses. In this study, miRNAs associated with boron stress were identified and characterized in barley. miRNA profiles were also comparatively analyzed between root and leave samples. A total of 31 known and 3 new miRNAs were identified in barley; 25 of them were found to respond to boron treatment. Several miRNAs were expressed in a tissue specific manner; for example, miR156d, miR171a, miR397, and miR444a were only detected in leaves. Additionally, a total of 934 barley transcripts were found to be specifically targeted and degraded by miRNAs. In silico analysis of miRNA target genes demonstrated that many miRNA targets are conserved transcription factors such as Squamosa promoter-binding protein, Auxin response factor (ARF), and the MYB transcription factor family. A majority of these targets were responsible for plant growth and response to environmental changes. We also propose that some of the miRNAs in barley such as miRNA408 might play critical roles against boron exposure. In conclusion, barley may use several pathways and cellular processes targeted by miRNAs to cope with boron stress

    Compulsory admissions of patients with mental disorders : State of the art on ethical and legislative aspects in 40 European countries

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    Copyright: This record is sourced from MEDLINE/PubMed, a database of the U.S. National Library of MedicineBACKGROUND.: Compulsory admission procedures of patients with mental disorders vary between countries in Europe. The Ethics Committee of the European Psychiatric Association (EPA) launched a survey on involuntary admission procedures of patients with mental disorders in 40 countries to gather information from all National Psychiatric Associations that are members of the EPA to develop recommendations for improving involuntary admission processes and promote voluntary care. METHODS.: The survey focused on legislation of involuntary admissions and key actors involved in the admission procedure as well as most common reasons for involuntary admissions. RESULTS.: We analyzed the survey categorical data in themes, which highlight that both medical and legal actors are involved in involuntary admission procedures. CONCLUSIONS.: We conclude that legal reasons for compulsory admission should be reworded in order to remove stigmatization of the patient, that raising awareness about involuntary admission procedures and patient rights with both patients and family advocacy groups is paramount, that communication about procedures should be widely available in lay-language for the general population, and that training sessions and guidance should be available for legal and medical practitioners. Finally, people working in the field need to be constantly aware about the ethical challenges surrounding compulsory admissions.Peer reviewe

    The Phrenic Component of Acute Schizophrenia – A Name and Its Physiological Reality

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    Decreased heart rate variability (HRV) was shown for unmedicated patients with schizophrenia and their first-degree relatives, implying genetic associations. This is known to be an important risk factor for increased cardiac mortality in other diseases. The interaction of cardio-respiratory function and respiratory physiology has never been investigated in the disease although it might be closely related to the pattern of autonomic dysfunction. We hypothesized that increased breathing rates and reduced cardio-respiratory coupling in patients with acute schizophrenia would be associated with low vagal function. We assessed variability of breathing rates and depth, HRV and cardio-respiratory coupling in patients, their first-degree relatives and controls at rest. Control subjects were investigated a second time by means of a stress task to identify stress-related changes of cardio-respiratory function. A total of 73 subjects were investigated, consisting of 23 unmedicated patients, 20 healthy, first-degree relatives and 30 control subjects matched for age, gender, smoking and physical fitness. The LifeShirt®, a multi-function ambulatory device, was used for data recording (30 minutes). Patients breathe significantly faster (p<.001) and shallower (p<.001) than controls most pronouncedly during exhalation. Patients' breathing is characterized by a significantly increased amount of middle- (p<.001), high- (p<.001), and very high frequency fluctuations (p<.001). These measures correlated positively with positive symptoms as assessed by the PANSS scale (e.g., middle frequency: r = 521; p<.01). Cardio-respiratory coupling was reduced in patients only, while HRV was decreased in patients and healthy relatives in comparison to controls. Respiratory alterations might reflect arousal in acutely ill patients, which is supported by comparable physiological changes in healthy subjects during stress. Future research needs to further investigate these findings with respect to their physiological consequences for patients. These results are invaluable for researchers studying changes of biological signals prone to the influence of breathing rate and rhythm (e.g., functional imaging)

    Compulsory admissions of patients with mental disorders : State of the art on ethical and legislative aspects in 40 European countries

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    Background. Compulsory admission procedures of patients with mental disorders vary between countries in Europe. The Ethics Committee of the European Psychiatric Association (EPA) launched a survey on involuntary admission procedures of patients with mental disorders in 40 countries to gather information from all National Psychiatric Associations that are members of the EPA to develop recommendations for improving involuntary admission processes and promote voluntary care. Methods. The survey focused on legislation of involuntary admissions and key actors involved in the admission procedure as well as most common reasons for involuntary admissions. Results. We analyzed the survey categorical data in themes, which highlight that both medical and legal actors are involved in involuntary admission procedures. Conclusions. We conclude that legal reasons for compulsory admission should be reworded in order to remove stigmatization of the patient, that raising awareness about involuntary admission procedures and patient rights with both patients and family advocacy groups is paramount, that communication about procedures should be widely available in lay-language for the general population, and that training sessions and guidance should be available for legal and medical practitioners. Finally, people working in the field need to be constantly aware about the ethical challenges surrounding compulsory admissions.Peer reviewe

    Chlamydia Pneumonia Seropositivity Correlates With Serum Fibrinogen And Lipoprotein A Levels: Any Role In Atherosclerosis?

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    The aim of the study is to determine the impact of Chlamydial seropositivity on atherosclerosis in a group of patient requiring coronary and/or carotid revascularization. A population of 30 diabetic patients (group 3) and 26 nondiabetic patients (group 2) with angiographically documented coronary and/or carotid artery disease were enrolled for the study. Volunteers from the relatives of hospital staff with no known disease (n=29; group 1) were included as the control group. Serum samples from the participants were assayed for cardiovascular risk factors including total serum cholesterol, triglyceride and lipoprotein levels, fibrinogen, Hb Al, levels and IgG titers for Chlamydia pneumonia (C. pneumonia). Chlamydial seropositivity was analysed further to determine a possible impact on atherogenesis. Serum LDL cholesterol levels revealed statistically significant difference between groups 1 and 2 (p=0.001). There was no difference between groups 2 and 3 regarding LDL cholesterol levels. There was no significant difference among the groups with respect to C. pneumonia seropositivity and the other atherosclerotic risk factors. Chlamydial seropositivity was found to be more frequent in males than in females (p=0.008). In the C. pneumonia seropositive group, serum fibrinogen and lipoprotein a levels were found to be significantly higher than the seronegative group (p=0.0001 and p=0.001, respectively). Other atherogenic risk factors were similar in the seropositive and negative groups. The causal role of Chlamydial infections in atherosclerotic plaque formation might be due to their influence on the serum fibrinogen and lipoprotein a levels.WoSScopu

    First assessment of the plant phenology index (PPI) for estimating gross primary productivity in African semi-arid ecosystems

    No full text
    The importance of semi-arid ecosystems in the global carbon cycle as sinks for CO 2 emissions has recently been highlighted. Africa is a carbon sink and nearly half its area comprises arid and semi-arid ecosystems. However, there are uncertainties regarding CO 2 fluxes for semi-arid ecosystems in Africa, particularly savannas and dry tropical woodlands. In order to improve on existing remote-sensing based methods for estimating carbon uptake across semi-arid Africa we applied and tested the recently developed plant phenology index (PPI). We developed a PPI-based model estimating gross primary productivity (GPP) that accounts for canopy water stress, and compared it against three other Earth observation-based GPP models: the temperature and greenness (T-G) model, the greenness and radiation (GöR) model and a light use efficiency model (MOD17). The models were evaluated against in situ data from four semi-arid sites in Africa with varying tree canopy cover (3–65%). Evaluation results from the four GPP models showed reasonable agreement with in situ GPP measured from eddy covariance flux towers (EC GPP) based on coefficient of variation (R 2 ), root-mean-square error (RMSE), and Bayesian information criterion (BIC). The GöR model produced R 2 = 0.73, RMSE = 1.45 g C m −2 d −1 , and BIC = 678; the T-G model produced R 2 = 0.68, RMSE = 1.57 g C m −2 d −1 , and BIC = 707; the MOD17 model produced R 2 = 0.49, RMSE = 1.98 g C m −2 d −1 , and BIC = 800. The PPI-based GPP model was able to capture the magnitude of EC GPP better than the other tested models (R 2 = 0.77, RMSE = 1.32 g C m −2 d −1 , and BIC = 631). These results show that a PPI-based GPP model is a promising tool for the estimation of GPP in the semi-arid ecosystems of Africa

    Downregulated MicroRNA-200a in Meningiomas Promotes Tumor Growth by Reducing E-Cadherin and Activating the Wnt/-Catenin Signaling Pathway

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    Meningiomas, one of the most common human brain tumors, are derived from arachnoidal cells associated with brain meninges, are usually benign, and are frequently associated with neurofibromatosis type 2. Here, we define a typical human meningioma microRNA (miRNA) profile and characterize the effects of one downregulated miRNA, miR-200a, on tumor growth. Elevated levels of miR-200a inhibited meningioma cell growth in culture and in a tumor model in vivo. Upregulation of miR-200a decreased the expression of transcription factors ZEB1 and SIP1, with consequent increased expression of E-cadherin, an adhesion protein associated with cell differentiation. Downregulation of miR-200a in meningiomas and arachnoidal cells resulted in increased expression of -catenin and cyclin D1 involved in cell proliferation. miR-200a was found to directly target -catenin mRNA, thereby inhibiting its translation and blocking Wnt/-catenin signaling, which is frequently involved in cancer. A direct correlation was found between the downregulation of miR-200a and the upregulation of -catenin in human meningioma samples. Thus, miR-200a appears to act as a multifunctional tumor suppressor miRNA in meningiomas through effects on the E-cadherin and Wnt/-catenin signaling pathways. This reveals a previously unrecognized signaling cascade involved in meningioma tumor development and highlights a novel molecular interaction between miR-200a and Wnt signaling, thereby providing insights into novel therapies for meningiomas
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