1,455 research outputs found

    Multiple Sclerosis and Schizophrenia

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    The psychiatric and neurological aspects of health may present methodological challenges in the diagnosis and treatment of disease. This is especially true for patients whose symptoms indicate the coexistence of multiple sclerosis (MS) and schizophrenia (SCZ). These cases raise critical questions regarding the relationship between the mind and the brain. Studies have noted that patients with MS have an increased risk of developing SCZ or bipolar disorder (BD). It is suggested here that MS and a subgroup of SCZ have similar etiologies. Factors such as gender, ethnicity, geography and season also have an influence on the occurrence of MS and SCZ. This paper aims to examine the differences and similarities between SCZ and MS. For this purpose, scientific papers examining various factors associated with these disorders were reviewed, and similarities and differences in genetic, immunological, seasonal, geographical, and gender-related risk factors and limited similarities in ethnic factors between the two diseases were identified. The findings suggest that subgroups of these two diseases may belong to the same class of disorders

    Isoprene emission from Sphagnum species occupying different growth positions above the water table

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    Isoprene emission from Sphagnum species naturally growing at different positions above the water table were measured in a subarctic peatland and at monoliths from a temperate bog. Our objectives were to investigate (1) whether emission rates were species and/or moisture dependent, and (2) whether short-term temperature history had an influence on emission capacity. We expected greater emission capacities in moist than dry growing conditions, and from species adapted to wet habitats. We also expected that higher emission capacities would be found in response to elevated temperatures. Average peak growing season isoprene emission capacities (standardized to 20 degrees C and PAR 1000 mu mol m(-2) s(-1)) at the subarctic site were 106 and 74 mu g C m(-2) h(-1) from a S. balticum wet lawn and a S. balticum dry hummock/palsa, respectively. Emission capacities correlated strongly with gross primary productivity (GPP) and the average air temperature of the 48 hours prior to measurement (T-48), but the effect of T-48 seemed to be partly masked by the influence of GPP when moisture was not limiting. The laboratory experiments suggested that a typical hummock species, S. rubellum had higher capacity for isoprene emission than a typical lawn species S. magellanicum. Instantaneous emission rates increased with temperature, but no effect of temperature history was discernible. Sphagnum mosses are known to emit substantial amounts of isoprene, but in this study we also showed significant inter-species differences in emission capacity. The results imply that climate change induced alterations of peatland hydrology may change the total ecosystem isoprene source strength, as individual species adapt to new growth conditions or as a consequence of species succession

    Determinants and predictability of global wildfire emissions

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    Biomass burning is one of the largest sources of atmospheric trace gases and aerosols globally. These emissions have a major impact on the radiative balance of the atmosphere and on air quality, and are thus of significant scientific and societal interest. Several datasets have been developed that quantify those emissions on a global grid and offered to the atmospheric modelling community. However, no study has yet attempted to systematically quantify the dependence of the inferred pyrogenic emissions on underlying assumptions and input data. Such a sensitivity study is needed for understanding how well we can currently model those emissions and what the factors are that contribute to uncertainties in those emission estimates. <br><br> Here, we combine various satellite-derived burned area products, a terrestrial ecosystem model to simulate fuel loads and the effect of fire on ecosystem dynamics, a model of fuel combustion, and various emission models that relate combusted biomass to the emission of various trace gases and aerosols. We carry out simulations with varying parameters for combustion completeness and fuel decomposition rates within published estimates, four different emissions models and three different global burned-area products. We find that variations in combustion completeness and simulated fuel loads have the largest impact on simulated global emissions for most species, except for some with highly uncertain emission factors. Variation in burned-area estimates also contribute considerably to emission uncertainties. We conclude that global models urgently need more field-based data for better parameterisation of combustion completeness and validation of simulated fuel loads, and that further validation and improvement of burned area information is necessary for accurately modelling global wildfire emissions. The results are important for chemical transport modelling studies, and for simulations of biomass burning impacts on the atmosphere under future climate change scenarios

    Climate, CO₂ and demographic impacts on global wildfire emissions

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    Abstract. Wildfires are by far the largest contributor to global biomass burning and constitute a large global source of atmospheric traces gases and aerosols. Such emissions have a considerable impact on air quality and constitute a major health hazard. Biomass burning also influences the radiative balance of the atmosphere and is thus not only of societal, but also of significant scientific interest. There is a common perception that climate change will lead to an increase in emissions as hot and dry weather events that promote wildfire will become more common. However, even though a few studies have found that the inclusion of CO2 fertilisation of photosynthesis and changes in human population patterns will tend to somewhat lower predictions of future wildfire emissions, no such study has included full ensemble ranges of both climate predictions and population projections, including the effect of different degrees of urbanisation. Here, we present a series of 124 simulations with the LPJ–GUESS–SIMFIRE global dynamic vegetation–wildfire model, including a semi-empirical formulation for the prediction of burned area based on fire weather, fuel continuity and human population density. The simulations use Climate Model Intercomparison Project 5 (CMIP5) climate predictions from eight Earth system models. These were combined with two Representative Concentration Pathways (RCPs) and five scenarios of future human population density based on the series of Shared Socioeconomic Pathways (SSPs) to assess the sensitivity of emissions to the effect of climate, CO2 and humans. In addition, two alternative parameterisations of the semi-empirical burned-area model were applied. Contrary to previous work, we find no clear future trend of global wildfire emissions for the moderate emissions and climate change scenario based on the RCP 4.5. Only historical population change introduces a decline by around 15 % since 1900. Future emissions could either increase for low population growth and fast urbanisation, or continue to decline for high population growth and slow urbanisation. Only for high future climate change (RCP8.5), wildfire emissions start to rise again after ca. 2020 but are unlikely to reach the levels of 1900 by the end of the 21st century. We find that climate warming will generally increase the risk of fire, but that this is only one of several equally important factors driving future levels of wildfire emissions, which include population change, CO2 fertilisation causing woody thickening, increased productivity and fuel load and faster litter turnover in a warmer climate

    Benefits and trade-offs of optimizing global land use for food, water, and carbon

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    Current large-scale patterns of land use reflect history, local traditions, and productioncosts, much more so than they reflect biophysical potential or global supply anddemand for food and freshwater, or—more recently—climate change mitigation. Wequantified alternative land-use allocations that consider trade-offs for these demandsby combining a dynamic vegetation model and an optimization algorithm to determinePareto-optimal land-use allocations under changing climate conditions in 2090–2099and alternatively in 2033–2042. These form the outer bounds of the option spacefor global land-use transformation. Results show a potential to increase all threeindicators (+83% in crop production,+8% in available runoff, and+3% in carbonstorage globally) compared to the current land-use configuration, with clear land-use priority areas: Tropical and boreal forests were preserved, crops were produced intemperate regions, and pastures were preferentially allocated in semiarid grasslands andsavannas. Transformations toward optimal land-use patterns would imply extensivereconfigurations and changes in land management, but the required annual land-usechanges were nevertheless of similar magnitude as those suggested by established land-use change scenarios. The optimization results clearly show that large benefits couldbe achieved when land use is reconsidered under a “global supply” perspective with aregional focus that differs across the world’s regions in order to achieve the supply ofkey ecosystem services under the emerging global pressures

    G691S/S904S polymorphism in the RET protooncogene of a 25-year-old medical student with bilateral pheochromocytoma

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    The case of a 25-year-old medical student with bilateral pheochromocytoma is described. Following diagnostic testing, tumors were surgically removed. Genetic analysis revealed that the patient is a heterozygote with the following mutations on opposite homologs: G691S (exon 11) and S904S (TCC-TCG, exon 15), suggesting the diagnosis of multiple endocrine neoplasia 2A (MEN2A). A diagnosis of MEN2 would be an indication of thyroidectomy in this patient. Although this mutation is described in the literature, it has no known connection to pheochromocytomas. Therefore, it is unknown whether there is a causal connection between the G691S genotype and the pheochromocytomas in this patient. If so, G691S is to be added to the list of genotypes causing MEN2A. Here, the procedure of sequencing the RET protooncogene is described and a possible association between the G691S genotype and MEN2A is discussed

    Modelling the global photovoltaic potential on land and its sensitivity to climate change

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    Solar photovoltaic (PV) energy is fundamental for decarbonizing the global economy and supporting the renewable energy transitions that are needed to combat climate change. Potential solar power production at a given location is a function of climatic variables that will change over time and so climate change needs to be accounted for in PV potential estimation. The future potential of PV in response to climate change has not previously been assessed consistently and globally across alternative scenarios. We develop global gridded estimates of PV potential between 2020 and 2100 as a function of spatial, climatic, technological and infrastructural conditions. We find a global technical potential of 175 111 T W h yr−1 in 2050, which changes by between ca. −19% (high-emission scenario) and +16% (low-emission scenario), with larger geographic variations within these scenarios. We perform a sensitivity analysis to identify key uncertainties and assess the scope for emerging PV technologies to offset negative climate impacts. We find that suboptimal orientation and temperature losses have the largest negative effects (reducing PV potential by up to ca. 50% and ca. 10% respectively), but that new technologies may be able to generate gains of more than 200% if successfully deployed worldwide. Solar power can make an important contribution to energy production over the coming decades and the demand for renewable energy could be met by PV deployment on between 0.5% and 1% of the global land area, provided its deployment accounts for the location-specific impacts of climate change.</p
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