2,231 research outputs found

    Tuberkuloosne meningiit

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    Tuberkuloosne meningiit on arenenud riikides harva esinev, kuid raske ning halva prognoosiga kopsuvälise tuberkuloosi vorm. Hoolimata väikesest esinemissagedusest peab kesknärvisüsteemi infektsiooni kahtluse korral kaaluma võimaliku etioloogiana ka tuberkuloosinakkust, eriti inimese immuunpuudulikkuse viiruse infektsiooni kaasumisel või muude immuunsüsteemi pärssivate seisundite korral. Sümptomid ja radioloogiline leid on mittespetsiifilised ning sarnanevad teiste neuroinfektsioonide omaga ning vahel ka aju vaskulaarsete haiguste kliinilise väljendusega. Et vähendada neuroloogiliste jääknähtude tekke ning surma riski, on kiire diagnoosimine ja raviga alustamine esmatähtis. Artikli eesmärk on anda ülevaade tuberkuloosse meningiidi riskiteguritest, avaldumisest, diagnoosimeetoditest ja ravist. &nbsp

    Controls on the emission of plant volatiles through stomata: Differential sensitivity of emission rates to stomatal closure explained

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    [1] Volatile (VOC) flux from leaves may be expressed as G(S)DeltaP, where G(S) is stomatal conductance to specific compound and DeltaP partial pressure gradient between the atmosphere and substomatal cavities. It has been suggested that decreases in G(S) are balanced by increases in DeltaP such that stomata cannot control VOC emission. Yet, responses of emission rates of various volatiles to experimental manipulations of stomatal aperture are contrasting. To explain these controversies, a dynamic emission model was developed considering VOC distribution between gas and liquid phases using Henry's law constant (H, Pa m(3) mol(-1)). Our analysis demonstrates that highly volatile compounds such as isoprene and monoterpenes with H values on the order of 10(3) have gas and liquid pool half-times of a few seconds, and thus cannot be controlled by stomata. More soluble compounds such as alcohols and carboxylic acids with H values of 10(-2)-10(1) are controlled by stomata with the degree of stomatal sensitivity varying with H. Inability of compounds with high solubility to support a high partial pressure, and thus to balance DeltaP in response to a decrease in G(S) is the primary explanation for different stomatal sensitivities. For compounds with low H, the analysis predicts bursts of emission after stomatal opening that accord with experimental observations, but that cannot be currently explained. Large within-leaf VOC pool sizes in compounds with low H also increase the system inertia to environmental fluctuations. In conclusion, dynamic models are necessary to simulate diurnal variability of the emissions of compounds that preferably partition to aqueous phase

    Environmental changes in SE Estonia during the last 700 years

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    Quantitative patterns between plant volatile emissions induced by biotic stresses and the degree of damage

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    Plants have to cope with a plethora of biotic stresses such as herbivory and pathogen attacks throughout their life cycle. The biotic stresses typically trigger rapid emissions of volatile products of lipoxygenase (LOX) pathway (LOX products: various C(6) aldehydes, alcohols, and derivatives, also called green leaf volatiles) associated with oxidative burst. Further a variety of defense pathways is activated, leading to induction of synthesis and emission of a complex blend of volatiles, often including methyl salicylate, indole, mono-, homo-, and sesquiterpenes. The airborne volatiles are involved in systemic responses leading to elicitation of emissions from non-damaged plant parts. For several abiotic stresses, it has been demonstrated that volatile emissions are quantitatively related to the stress dose. The biotic impacts under natural conditions vary in severity from mild to severe, but it is unclear whether volatile emissions also scale with the severity of biotic stresses in a dose-dependent manner. Furthermore, biotic impacts are typically recurrent, but it is poorly understood how direct stress-triggered and systemic emission responses are silenced during periods intervening sequential stress events. Here we review the information on induced emissions elicited in response to biotic attacks, and argue that biotic stress severity vs. emission rate relationships should follow principally the same dose–response relationships as previously demonstrated for different abiotic stresses. Analysis of several case studies investigating the elicitation of emissions in response to chewing herbivores, aphids, rust fungi, powdery mildew, and Botrytis, suggests that induced emissions do respond to stress severity in dose-dependent manner. Bi-phasic emission kinetics of several induced volatiles have been demonstrated in these experiments, suggesting that next to immediate stress-triggered emissions, biotic stress elicited emissions typically have a secondary induction response, possibly reflecting a systemic response. The dose–response relationships can also vary in dependence on plant genotype, herbivore feeding behavior, and plant pre-stress physiological status. Overall, the evidence suggests that there are quantitative relationships between the biotic stress severity and induced volatile emissions. These relationships constitute an encouraging platform to develop quantitative plant stress response models

    Changes in floral bouquets from compound-specific responses to increasing temperatures

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    We addressed the potential effects of changes in ambient temperature on the profiles of volatile emissions from flowers and tested whether warming could induce significant quantitative and qualitative changes in floral emissions, which would potentially interfere with plant-pollinator chemical communication. We measured the temperature responses of floral emissions of various common species of Mediterranean plants using dynamic headspace sampling and used GC-MS to identify and quantify the emitted terpenes. Floral emissions increased with temperature to an optimum and thereafter decreased. The responses to temperature modeled here predicted increases in the rates of floral terpene emission of 0.03-1.4-fold, depending on the species, in response to an increase of 1 °C in the mean global ambient temperature. Under the warmest projections that predict a maximum increase of 5 °C in the mean temperature of Mediterranean climates in the Northern Hemisphere by the end of the century, our models predicted increases in the rates of floral terpene emissions of 0.34-9.1-fold, depending on the species. The species with the lowest emission rates had the highest relative increases in floral terpene emissions with temperature increases of 1-5 °C. The response of floral emissions to temperature differed among species and among different compounds within the species. Warming not only increased the rates of total emissions, but also changed the ratios among compounds that constituted the floral scents, i.e. increased the signal for pollinators, but also importantly altered the signal fidelity and probability of identification by pollinators, especially for specialists with a strong reliance on species-specific floral blends

    The comparative analysis of financial performance of Estonian agricultural company in 2014-2021 based on FADN database and Statistical Board data

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    Magistritöö Majandusarvestuse ja finantsjuhtimise õppekavalPõllumajandusettevõtete hea majanduslik seis on aluseks maapiirkonna arengule, toiduga kindlustatusele ning põllumajanduspoliitika otsuste aluseks olevatele mõjuanalüüsidele. Varasemates uuringutes on autorid välja toonud, et põllumajandusettevõtete majanduslikku seisu ei ole piisavalt uuritud ning kasutatakse varade puhasrentaablust ja omakapitali rentaablust. Põllumajanduspoliitika otsuste aluseks olevate mõjuanalüüside koostamise probleem on aga, milliseid andmeid ja millisest andmebaasist analüüsiks rakendada. Magistritöö eesmärk on võrrelda kahe erineva andmebaasi andmetel finantstulemuslikkust Eesti põllumajandusettevõtetes kaheksa aastase perioodi jooksul. Töö teoreetilises osas selgitati finantstulemuslikkuse hindamise vajadust põllumajandusettevõtetes ning hindamist suhtarvude abil. Magistritöö empiirilises osas arvutati FADN andmebaasi ja Statistikaameti baasil Eesti põllumajandusettevõtetes varade puhasrentaablus, omakapitali rentaablus, käiberentaablus ning kasutatud kapitali rentaablus. Analüüsiks jaotati FADN andmed tootmistüüpide ning suurusgruppide lõikes, Statistikaameti andmed suurusgruppide lõikes. Lisaks võrreldi kahe andmebaasi finantstulemuslikkuse näitajaid. Analüüsi käigus selgus, et tootmistüüpide lõikes olid kõige kõrgemad finantstulemuslikkuse näitajad taimekasvatuse tootmistüübis. Suurusgruppide lõikes mikro ning väikese suurusega ettevõtetes. Kahe andmebaasi näitajate võrdlusel leiti, et Statistikaameti rentaablusnäitajad olid mõnevõrra kõrgemad kui FADN andmebaasi andmetel. Edasiste uuringute aluseks võiks olla kahe andmebaasi kasutatud kapitali rentaabluse erinevuse põhjuste väljaselgitamine.The good economic condition of agricultural enterprises is the basis for the development of rural areas, food security, and the impact analyzes underlying agricultural policy decisions. In previous studies, the authors have pointed out that the economic status of agricultural enterprises has not been sufficiently studied, and the net return on assets and return on equity are used. Is there also a significant difference in the results, depending on which database data is used for the analysis? The aim of the master's thesis is to compare the financial performance of Estonian agricultural enterprises during an eight-year period according to the data of two different databases. The theoretical part of the work explained the need for financial performance assessment in agricultural enterprises and the assessment using ratios. In the empirical part of the master's thesis, the net return on assets, return on equity, return on turnover and return on capital used in Estonian agricultural enterprises were calculated on the basis of the FADN database and Statistics Estonia. For the analysis, FADN data were divided by production types and size groups, Statistics Estonia data by size groups. In addition, the financial performance indicators of the two databases were compared. During the analysis, it was revealed that the highest financial performance indicators in terms of production types were in the crop production type. According to size groups, in micro and small-sized companies. When comparing the indicators of the two databases, it was found that the profitability indicators of Statistics Estonia were somewhat higher than the data of the FADN database. Further research could be based on finding out the reasons for the difference in the return on capital used in the two databases

    Analyzing the causes of method-to-method variability among Rubisco kinetic traits: from the first to the current measurements

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    Due to the importance of Rubisco in the biosphere, its kinetic parameters have been measured by different methodologies in a large number of studies over the last 60 years. These parameters are essential to characterize the natural diversity in the catalytic properties of the enzyme and they are also required for photosynthesis and cross-scale crop modeling. The present compilation of Rubisco kinetic parameters in model species revealed a wide intraspecific laboratory-to-laboratory variability, which was partially solved by making corrections to account for differences in the assay buffer composition and in the acidity constant of dissolved CO2, as well as for differences in the CO2 and O2 solubilities. Part of the intraspecific variability was also related to the different analytical methodologies used. For instance, significant differences were found between the two main methods for the determination of the specificity factor (Sc/o), and also between Rubisco quantification methods, Rubisco purification versus crude extracts, and single point versus CO2 curve measurements for the carboxylation turnover rate (kcatc) determination. Causes of the intraspecific laboratory-to-laboratory variability for Rubisco catalytic traits are discussed. This study provides a normalized kinetic dataset for model species to be used by the scientific community. Corrections and recommendations are also provided to reduce measurement variability, allowing the comparison of kinetic data obtained in different laboratories using different assay conditions
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