471 research outputs found

    Photosynthetic Response of Two Caragana Species to the Stimulated Climate Change in Mu Us Sand Land of Northwest China

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    Due to human activities, the concentration of carbon dioxide (CO2) in the Earth’s atmosphere is rising rapidly. The atmospheric CO2 concentration has increased to 360 ÎŒmol/mol from 280 ÎŒmol/mol at the end of the 19th century, and it will be doubled in the late 21st century (Alcamo 1996). Since CO2 is a key factor for plant growth and development, much more attention has been paid to the effect of an elevated atmospheric CO2 concentration on many ecosystem processes (Hungate et al. 1997; Idso et al. 1992; Oren et al. 2001; Sun et al. 2002). Caragana davazamcii and Caragana korshinskii which belong to legumes family play an extremely important role in protection soil from the wind, water conservation and eco-environment protection in Mu Us sand land of Northwest China. There have been a lot of research done on ecophysiological characteristics of caragana species under natural conditions, but there has been little focused on the physiological changes that may occur under stimulated CO2 enrichment. This study compares the changes of photosynthetic characteristics of two caragana species to simultaneous CO2 enrichment and explores their adaptation mechanisms

    Contributions of Different Regulatory Mechanisms to Osmotic Potential Changes in Three \u3cem\u3eCaragana\u3c/em\u3e Species on the Mongolian Plateau

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    The genus Caragana of legume family is endemic to the temperate grasslands of Eurasia (Cao et al., 1999). Caragana species are broadly distributed in the temperate Asia zone (E30°–140°, N28°–56°). Caragana microphylla, Caragana davazamcii, and Caragana korshinskii are typical representatives of the genus Caragana in central Asia. The three Caragana species exhibit a geographically substituted distribution from east (semi arid habitat) to west (arid habitat) on the Mongolian Plateau. Existing studies investigating the reasons for the interspecific geographical transition of the three Caragana species have primarily focused on RAPD analysis, photosynthetic capacity, and hydraulic architecture. In contrast, information on the adjustment mechanisms in Κπ changes remains limited; particularly regarding the relative contributions of the main three regulatory mechanisms knows little

    Response of Dynamic Change of Vegetation Index to Precipitation Fluctuations in Hulunbeier Typical Steppe

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    In arid and semi-arid regions, precipitation is an important environmental limiting factor for ecosystems, where precipitation characteristic parameters at different time scales have great variability (Mohammad and Howard, 2006), and the small precipitation events (\u3c 5 mm) is the subject of precipitation events (Loik et al., 2004, Sala and Lauenroth, 1982). In this study, we used vegetation index extracted from TM or MODIS image to establish the regression models between vegetation index and precipitation, and then analyzed the response of typical steppe vegetation to precipitation fluctuations. Our result can supply reference for the productivity measurement model in typical steppe

    Matriks Jordan Dan Aplikasinya Pada Sistem Linier Waktu Diskrit

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    Matrix is diagonalizable (similar with matrix diagonal) if and only if the sum of geometric multiplicities of its eigenvalues is n.If we search for an upper triangular form that is nearly diagonal as possible but is still attainable by similarity for every matrix, especially the sum of geometric multiplicities of its eigenvalues is less than n, the result is the Jordan canonical form, which is denoted by , and . In this paper, will be described how to get matrix S(in order to get matrix ) by using generalized eigenvector. In addition, it will also describe the Jordan canonical form and its properties, and some observation and application on discrete time linear system

    Regional Differences in Antithrombotic Treatment for Atrial Fibrillation:Insights from the GLORIA-AF Phase II Registry

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    Introduction Although guideline-adherent antithrombotic therapy (ATT) for stroke prevention in atrial fibrillation (AF) is associated with lower mortality and thromboembolism, ATT uptake shows geographic variation worldwide. We aimed to assess thromboembolic risk and baseline ATT by geographic region and identify factors associated with prescription of ATT in a large, truly global registry of patients with recently diagnosed AF. Methods and Results Our analysis comprises 15,092 patients newly diagnosed with non-valvular AF at risk for stroke, enrolled in Phase II of Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation (GLORIA-AF). Global oral anticoagulation (OAC) use was 79.9%, being highest in Europe (90.1%), followed by Africa/Middle East (87.4%) and Latin America (85.3%), North America (78.3%) and Asia (55.2%). Among OAC users, vitamin K antagonists (VKAs) have been replaced by non-VKA OACs (NOACs) as the more prevalent OAC option in all regions, with highest use in North America (66.5%) and lowest in Asia (50.2%). In Asia, OAC was 80.4% in community hospitals but only 49.8% in university hospitals and 42.6% in specialist offices, and varied from 21.0% in China to 89.7% in Japan (NOACs at 5.8% in China and 83.3% in Japan). Globally, 76.5% of low-risk patients were prescribed ATT (46.1% OAC), whereas 17.7% high-risk patients were not anticoagulated (Europe 8.8%; North America 18.9%; Asia 42.4%). Conclusion Substantial inter- and intra-regional differences in ATT for stroke prevention in AF are evident in this global registry. While guideline-adherent ATT can be further improved, NOACs are the main contributor to high OAC use worldwide.</jats:p

    Atrial fibrillation and comorbidities:Clinical characteristics and antithrombotic treatment in GLORIA-AF

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    BackgroundPatients with AF often have multimorbidity (the presence of ≄2 concomitant chronic conditions).ObjectiveTo describe baseline characteristics, patterns of antithrombotic therapy, and factors associated with oral anticoagulant (OAC) prescription in patients with AF and ≄2 concomitant, chronic, comorbid conditions.MethodsPhase III of the GLORIA-AF Registry enrolled consecutive patients from January 2014 through December 2016 with recently diagnosed AF and CHA2DS2-VASc score ≄1 to assess the safety and effectiveness of antithrombotic treatment.ResultsOf 21,241 eligible patients, 15,119 (71.2%) had ≄2 concomitant, chronic, comorbid conditions. The proportions of patients with multimorbidity receiving non-vitamin K antagonist oral anticoagulants (NOACs) and vitamin K antagonists (VKA) were 60.2% and 23.6%, respectively. The proportion with paroxysmal AF was 57.0% in the NOAC group and 45.4% in the VKA group. Multivariable log-binomial regression analysis found the following factors were associated with no OAC prescription: pattern of AF (paroxysmal, persistent, or permanent), coronary artery disease, myocardial infarction, prior bleeding, smoking status, and region (Asia, North America, or Europe). Factors associated with OAC prescriptions were age, body mass index, renal function, hypertension, history of cerebral ischemic symptoms, and AF ablation.ConclusionMultimorbid AF patients prescribed NOACs have fewer comorbidities than those prescribed VKAs. Age, AF pattern, comorbidities, and renal function are associated with OAC prescription
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