1,084 research outputs found

    Soil organic carbon stocks controlled by lithology and soil depth in a Peruvian alpine grassland of the Andes

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    The soil is the largest carbon (C) pool in the terrestrial ecosystem, and soil organic carbon (SOC) stocks play an important role in global C dynamics. Alpine grasslands of the Andes are characterized by high SOC stocks. Quantifying SOC stocks and unraveling key factors controlling SOC stocks, is necessary to obtain a better understanding of the dynamics of the large C stocks in this environment. However, most studies on C dynamics of the Andes focus on volcanic-ash soils, whereas information about non-volcanic ash soils in this region is scarce. Our objectives were: (i) to estimate SOC stocks in an alpine grassland of the Peruvian Andes (7Ā° 11ā€²S, 78Ā° 35ā€²W) with parent materials other than volcanic ash, and (ii) to identify the underlying soil formation and environmental (SFE) factors and soil properties explaining observed patterns of SOC stocks. We sampled 69 plots up to the parent material to measure soil properties and to calculate SOC stocks, in relation to lithology, land use, grazing intensity, slope angle, slope position and altitude. We applied linear models to identify key factors controlling SOC stocks. Our results showed that total SOC stocks had a mean value of 215 Ā± 21 T haāˆ’1 , whereas SOC stocks of the upper 10 cm and 40 cm comprised 29.3% and 80.0% of total SOC stocks respectively. The variation of the total SOC stocks was mainly explained by soil depth and soil moisture. When soil depth and soil moisture were controlled as conditional variables, lithology became the key factor controlling the total SOC stocks. For the SOC stocks of the upper 10 cm, soil moisture explained a large part of the variation, whereas lithology, grazing intensity and altitude were also significant predictors. Our results also show that when soils are sampled with limited depths instead of the entire soil profile, SOC stocks can be underestimated, and the effects of the SFE factors on SOC stocks can be overestimated

    Mid-range visual deficits after stroke:Prevalence and co-occurrence

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    Visual deficits are common after stroke and are powerful predictors for the chronic functional outcome. However, while basic visual field and recognition deficits are relatively easy to assess with standardized methods, selective deficits in visual primitives, such as shape or motion, are harder to identify, as they often require a symmetrical bilateral posterior lesion in order to provoke full field deficits. Therefore, we do not know how often they occur. Nevertheless, they can have severe repercussions for daily-life functioning. We aimed to investigate the prevalence and co-occurrence of hemifield ā€œmid-rangeā€ visual deficits (i.e. color, shape, location, orientation, correlated motion, contrast, texture and glossiness), using a novel experimental set-up with a gaze-contingent presentation of the stimuli. To this end, a prospective cohort of 220 ischemic (sub)cortical stroke patients and a healthy control group was assessed with this set-up. When comparing performance of patients with controls, the results showed that deficits in motion-perception were most prevalent (26%), followed by color (22%), texture (22%), location (21%), orientation (18%), contrast (14%), shape (14%) and glossiness (13%). 63% of the stroke patients showed one or more mid-range visual deficits. Overlap of deficits was small; they mostly occurred in isolation or co-occurred with only one or two other deficits. To conclude, it was found that deficits in ā€œmid-rangeā€ visual functions were very prevalent. These deficits are likely to affect the chronic post-stroke condition. Since we found no strong patterns of co-occurrences, we suggest that an assessment of deficits at this level of visual processing requires screening the full range of visual functions

    Emotion Recognition and Traffic-Related Risk-Taking Behavior in Patients with Neurodegenerative Diseases

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    Objectives : Neurodegenerative diseases (NDDs), such as Alzheimer's disease, frontotemporal dementia, dementia with Lewy bodies, and Huntington's disease, inevitably lead to impairments in higher-order cognitive functions, including the perception of emotional cues and decision-making behavior. Such impairments are likely to cause risky daily life behavior, for instance, in traffic. Impaired recognition of emotional expressions, such as fear, is considered a marker of impaired experience of emotions. Lower fear experience can, in turn, be related to risk-taking behavior. The aim of our study was to investigate whether impaired emotion recognition in patients with NDD is indeed related to unsafe decision-making in risky everyday life situations, which has not been investigated yet.Ā  Methods: Fifty-one patients with an NDD were included. Emotion recognition was measured with the Facial Expressions of Emotions: Stimuli and Test (FEEST). Risk-taking behavior was measured with driving simulator scenarios and the Action Selection Test (AST). Data from matched healthy controls were used: FEEST (n = 182), AST (n = 36), and driving simulator (n = 18).Ā Ā  Results: Compared to healthy controls, patients showed significantly worse emotion recognition, particularly of anger, disgust, fear, and sadness. Furthermore, patients took significantly more risks in the driving simulator rides and the AST. Only poor recognition of fear was related to a higher amount of risky decisions in situations involving a direct danger.Ā Ā  Conclusions: To determine whether patients with an NDD are still fit to drive, it is crucial to assess their ability to make safe decisions. Measuring emotion recognition may be a valuable contribution to this judgment

    Norditerpenoids with selective anti-cholinesterase activity from the roots of Perovskia atriplicifolia Benth

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    Inhibition of cholinesterases remains one of a few available treatment strategies for neurodegenerative dementias such as Alzheimer's disease and related conditions. The current study was inspired by previous data on anticholinesterase properties of diterpenoids from Perovskia atriplicifolia and other Lamiaceae species. The acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibition by the three new natural compounds-(1R,15R)-1-acetoxycryptotanshinone (1), (1R)-1-acetoxytanshinone IIA (2), and (15R)-1-oxoaegyptinone A (3)-as well as, new for this genus, isograndifoliol (4) were assessed. Three of these compounds exhibited profound inhibition of butyrylcholinesterase (BChE) and much weaker inhibition of acetylcholinesterase (AChE). All compounds (1-4) selectively inhibited BChE (IC(50) = 2.4, 7.9, 50.8, and 0.9 ĀµM, respectively), whereas only compounds 3 and 4 moderately inhibited AChE (IC(50) 329.8 ĀµM and 342.9 ĀµM). Molecular docking and in silico toxicology prediction studies were also performed on the active compounds. Natural oxygenated norditerpenoids from the traditional Central Asian medicinal plant P. atriplicifolia are selective BChE inhibitors. Their high potential makes them useful candidate molecules for further investigation as lead compounds in the development of a natural drug against dementia caused by neurodegenerative diseases

    Role of macrophage sialoadhesin in host defense against the sialylated pathogen group B <em>Streptococcus</em>

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    ABSTRACT: Several bacterial pathogens decorate their surfaces with sialic acid (Sia) residues within cell wall components or capsular exopolysaccharides. Sialic acid expression can promote bacterial virulence by blocking complement activation or by engagement of inhibitory sialic acid-binding immunoglobulin-like lectins (Siglecs) on host leukocytes. Expressed at high levels on splenic and lymph node macrophages, sialoadhesin (Sn) is a unique Siglec with an elongated structure that lacks intracellular signaling motifs. Sialoadhesin allows macrophage to engage certain sialylated pathogens and stimulate inflammatory responses, but the in vivo significance of sialoadhesin in infection has not been shown. We demonstrate that macrophages phagocytose the sialylated pathogen group B Streptococcus (GBS) and increase bactericidal activity via sialoadhesin-sialic-acid-mediated recognition. Sialoadhesin expression on marginal zone metallophillic macrophages in the spleen trapped circulating GBS and restricted the spread of the GBS to distant organs, reducing mortality. Specific IgM antibody responses to GBS challenge were also impaired in sialoadhesin-deficient mice. Thus, sialoadhesin represents a key bridge to orchestrate innate and adaptive immune defenses against invasive sialylated bacterial pathogens. KEY MESSAGE: Sialoadhesin is critical for macrophages to phagocytose and clear GBS. Increased GBS organ dissemination in the sialoadhesin-deficient mice. Reduced anti-GBS IgM production in the sialoadhesin-deficient mice. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00109-014-1157-y) contains supplementary material, which is available to authorized users

    Contribution of peat compaction to relative sea-level rise within Holocene deltas

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    Modern and forecasted flooding of deltas is accelerated by subsidence of Holocene deposits. Subsidence caused by tectonics, isostasy, sediment compaction and anthropogenic processes, combined with eustatic sea-level rise, results in drowning and increased flood risk within densely populated deltas. Many deltaic sedimentary successions include substantial amounts of peat, which is highly compressible compared to clay, silt and sand. Peat compaction, therefore, may contribute considerably to total delta subsidence. Existing studies are inadequate for quantifying peat compaction across deltas. We present a numerical peat compaction model calibrated with an extensive field dataset. The model quantifies spatial and temporal trends in peat compaction within fluvial-dominated Holocene flood basin sequences of different compositions. Subsidence due to peat compaction is highly variable in time and space, with local rates of up to 15 mm/yr, depending on sedimentary sequence. This is extremely important information for developing sound delta management strategies. Artificial groundwater table lowering may cause substantial additional subsidence. Subsidence due to peat compaction might even exceed estimates of relative sea-level rise, and thus, may seriously increase the risk of delta drowning and human vulnerability to floodin

    Priorities and preferences of advanced soft tissue sarcoma patients starting palliative chemotherapy:baseline results from the HOLISTIC study

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    INTRODUCTION: Palliative chemotherapy is the principal treatment of patients with advanced soft tissue sarcomas (STS); however prognosis is limited (median overall survival 12-19 months). In this setting, patient values and priorities are central to personalised treatment decisions. PATIENTS AND METHODS: The prospective HOLISTIC study was conducted in the UK and the Netherlands assessing health-related quality of life in STS patients receiving palliative chemotherapy. Participants completed a questionnaire before starting chemotherapy, including attitudes towards quality of life (QoL) versus length of life (LoL), decisional control preferences, and decisional conflict. Chi-square and Fisherā€™s exact tests were used to evaluate associations between patient characteristics and preferences. RESULTS: One hundred and thirty-seven patients with advanced STS participated (UK: nĀ = 72, the Netherlands: nĀ = 65). Median age was 62 (27-79) years. Preference for extended LoL (nĀ = 66, 48%) was slightly more common than preference for QoL (nĀ = 56, 41%); 12 patients (9%) valued LoL and QoL equally (missing: nĀ = 3). Younger patients (age <40 years) prioritised LoL, whereas two-thirds of older patients (aged ā‰„65 years) felt that QoL was equally or more important than LoL (PĀ = 0.020). Decisional conflict was most common in patients who prioritised QoL (PĀ =Ā 0.024). Most patients preferred an active (nĀ = 45, 33%) or collaborative (nĀ = 59, 44%) role in treatment decisions. Gender, performance status, and country were significantly associated with preferred role. Concordance between preferred and actual role in chemotherapy decision was high (nĀ = 104, 76%). CONCLUSIONS: Heterogeneous priorities and preferences among advanced STS patients support personalised decisions about palliative treatment. Considering individual differences during treatment discussions may enhance communication and optimise patient-centred care
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