Keskkonnategurite mõju haava (Populus sp.) isopreeni emissioonile

Isoprene is the most abundant biogenic volatile organic compound (BVOC) emitted from a wide range of plant species. Isoprene plays important roles in plant physiology and atmospheric photochemistry. Emission of isoprene depends on plant ontogenetic development and is driven by short-term and long-term variations in environmental factors. In particular, the rise of atmospheric [CO2] and concomitant increases in temperature are potentially the key factors influencing isoprene emissions in future climates. The main aim of this thesis was to study the effects of elevated atmospheric [CO2] and plant ontogenetic stage on isoprene emissions from strong isoprene emitter aspen [European aspen (Populus tremula) and hybrid aspen P. tremula x P. tremuloides)] in order to improve the understanding of how acclimation to elevated growth [CO2] and ontogeny alter isoprene emission responses to instantaneous variations in environmental drivers. The present thesis tested five hypotheses: (i) Elevated growth [CO2] stimulates leaf area growth and leads to increased canopy isoprene emission rates; (ii) Elevated growth [CO2] alters both isoprene emission capacity and modifies isoprene emission responses to instantaneous variations in [CO2]; (iii) Elevated growth [CO2] modifies both the availability of the substrate for isoprene synthesis and isoprene synthase activity, and this results in altered isoprene emission responses to other environmental drivers such as light and temperature; (iv) Elevated [CO2] acclimated plants have a greater heat stress resistance by enhanced isoprene emissions at higher temperature; (v) With increasing leaf age, isoprene emission capacity decreases, but still adjusts to variations in environmental temperature in aging leaves. The effects of elevated [CO2] on isoprene emission were studied in 2-year-old hybrid aspen (P. tremula x P. tremuloides) grown at atmospheric CO2 concentrations of 380 mol mol-1 (ambient) and 780 mol mol-1 (elevated). On the canopy scale, isoprene emission rate under elevated [CO2] significantly exceeded that under current ambient [CO2]. The main reason for this response was stimulation of canopy leaf area growth by elevated [CO2] that exceeded the high [CO2]-inhibition of isoprene emission at leaf level. Under moderate temperatures, instantaneous increase in [CO2] inhibited isoprene emission rate by decreases in DMADP pool size. Long-term elevation in growth [CO2] also resulted in moderately lower isoprene emission rate due to lower DMADP pool size. However, this response was partly compensated by enhanced isoprene synthase activity. Elevated growth [CO2] enhanced hybrid aspen foliar photosynthetic and isoprene emission capacity, coupled with more developed photosynthetic tissues, e.g. higher mesophyll thickness and chloroplast number. The response curves of isoprene emission rate versus light and intercellular [CO2] were also modified by acclimation to elevated [CO2]. Elevated [CO2] grown plants had significantly higher isoprene emission rate under saturating light intensity and at low intercellular CO2 concentration close to the CO2 compensation point of photosynthesis, but a lower quantum yield of isoprene emission. Elevated growth [CO2] improved hybrid aspen thermotolerance reflected in lower depression of net assimilation rate coupled with higher isoprene emission rate, particularly under strong light and high [CO2]. Changes in isoprene emission rate during leaf ontogeny were studied from late summer to intensive leaf fall in mature trees of European aspen. Net assimilation and isoprene emission capacities decreased during senescence, and these changes we correlated with reductions in leaf nitrogen content. However, the decrease in isoprene emission rate was slower than in assimilation rate, and isoprene emission rate still adjusted to environmental temperature in senescing leaves. However, the temperature acclimation capacity was less in senescing leaves compared to leaves in mid-season. Taken together, the influence of elevated growth [CO2] on isoprene emission is multifaceted. Acclimation to elevated growth [CO2] may enhance canopy scale isoprene emission rate in moderate conditions, but especially under stress conditions. For accurate predictions of isoprene emissions under future conditions with higher atmospheric [CO2] and warmer temperatures, it is essential to consider the effects of plant acclimation to environment and ontogenetic stage. It is particularly important to consider both leaf- and canopy-scale processes.Isopreen on üks enam levinud biogeenne orgaaniline lenduvühend (BVOC – biogenic volatile organic compound), mida emiteerivad paljud taimeliigid. Isopreenil on oluline roll taimede füsioloogias ja atmosfääri fotokeemilistes protsessides. Isopreeni emissiooni mõjutab taime ontogeneetiline areng ning keskkonnategurite lühi- ja pikaajalised muutused. Atmosfääris suurenev CO2-sisaldus ja kaasnev temperatuuri tõus on võtmetegurid, mis võivad mõjutada isopreeni emissiooni tuleviku kliima tingimustes. Väitekirja peamine eesmärk oli uurida atmosfääris suurenenud CO2-sisalduse ja taime ontogeneetilise arengu mõju tugeva isopreeni eritajana tuntud haavale - harilikule haavale (Populus tremula) ja hübriidhaavale (P. tremula x P. tremuloides) ja osata paremini selgitada, kuidas kohanemine suurenenud CO2-sisaldusega ja ontogenees mõjutavad isopreeni eritamise kaudu taimede vastuseid lühiajalistele keskkonnategurite muutustele. Käesolevas töös kontrolliti viit hüpoteesi: (I) CO2 suurenenud sisaldus ergutab lehe pindala kasvu, mille tõttu kasvab võra lehtedest isopreeni eritamise kiirus; (II) CO2 suurenenud sisaldus muudab nii isopreeni eritamise võimet kui ka isopreeni eritamist lühiajaliselt muutuvates [CO2] tingimustes; (III) suurenenud [CO2] muudab nii substraadi valmisolekut isopreeni sünteesiks kui ka isopreeni süntaasi aktiivsust, mille tagajärjel muutub isopreeni eritamine tulenevalt ka teistest keskkonnateguritest nagu näiteks valgus ja tempeatuur; (IV) õhu suurenenud [CO2]-ga kohastunud taimed on kuumastressile vastupidavamad tänu isopreeni eritamise suurenemisele kõrgematel temperatuuridel; (V) lehe vananemisel isopreeni eritamise võime väheneb, reageerides siiski keskkonna temperatuuri muutustele lehe vananemise jooksul. Käesolevas töös uuriti isopreeni emissiooni 2-aastastel hübriidhaabadel (P. tremula x P. tremuloides), mis olid kasvanud erinevates tingimustes: ümbritsevas õhus, kus [CO2] oli 380 ϻmol mol-1 ja CO2 suurenenud sisaldusega õhus, kus [CO2] oli 780 ϻmol mol-1. Ümbritseva õhuga võrreldes oli suurenenud [CO2]-ga keskkonnas taimede isopreeni eritamise kiirus oluliselt suurem. Peamiseks põhjuseks oli suurenenud [CO2] mõjul lehestiku pindala suurenemine, mille mõju ületas samal ajal lehe tasandil toimunud isopreeni eritamise vähenemise. Mõõduka temperatuuri tingimustes pärssis lühiajaline [CO2] suurenemine isopreeni eritamise kiirust DMADP hulga vähenemisega. Pikaajaliselt suurenenud [CO2] tingimuses oli samuti isopreeni eritamine DMADP hulga vähenemise tõttu väiksem, kuid isopreeni süntaasi aktiivsuse tõus kompenseeris selle osaliselt. Suurenenud [CO2] ergutas hübriidhaava lehestiku fotosünteesi ja isopreeni eritamise võimet, millega kaasnes suurem fotosünteesiva koe hulk nagu paksem mesofüll ja kloroplastide arv. Isopreeni eritamise kiiruse ja rakkude vahelise CO2-sisalduse ning valguse sõltuvust väljendav kõver muutus samuti koos taimede kohastumisega suurenenud [CO2] tingimustes. Taimedel, mis olid kasvanud suurenenud [CO2]-ga keskkonnas, võis jälgida oluliselt suuremat isopreeni eritust küllastunud valguse ja rakkude vahelise madala CO2-sisalduse juures, mis asus fotosünteesi CO2 kompenseerimispunkti lähedal, kuid isopreeni eritamise kvantsaagis oli seejuures väiksem. Suurenenud [CO2]-ga keskkonnas kasvamine suurendas taimede termotolerantsi, mis peegeldus CO2 netoassimilatsiooni väiksemas depressioonis, millega kaasnes suurem isopreeni eritamise kiirus, eriti intensiivse valguse ja kõrge [CO2] tingimustes. Isopreeni eritamise kiiruse muutumist uuriti hariliku haava täiskasvanud puudel hilissuvest kuni intensiivse lehtede langemise ajani. CO2 netoassimilatsioon ja isopreeni eritamise võime vähenes lehestiku vananemise perioodil, korreleerudes lehe lämmastiku sisalduse vähenemisega. Kuigi isopreeni eritamise kiiruse vähenemine oli aeglasem kui CO2 assimilatsioon, kohanes isopreeni eritamise kiirus vananevates lehtedes vastavalt keskkonna temperatuurile. Kokkuvõtvalt võib väita, et suurenenud [CO2]-ga keskkonna mõju isopreeni eritamisele on mitmetine. Mõõdukates tingimustes võib suurenenud [CO2]-ga kohastumine ergutada isopreeni eritamist võras lehestiku tasandil, seda eriti stressi korral. Isopreeni emissiooni täpseks ennustamiseks, pidades silmas suurenenud [CO2]-ga ja temperatuuriga tuleviku kliimat, on oluline arvestada taimede kohastumist keskkonna ja taimede ontogeneetilisi etappe. Eriti oluline on võtta arvesse mõlemaid, nii lehe kui ka võras lehestiku tasandil toimuvaid protsesse

Highly Ordered Pd Nanowire Array by Template Fabrication for Propanol Electrooxidation

Highly ordered Pd nanowire arrays (NWAs) prepared by electrodeposition method using the fresh prepared anodic aluminum oxide (AAO) as the template have been characterized by X-ray diffraction pattern (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM), scanning electron microscopy (SEM), and electrochemical measurements. SEM results revealed that the brush-shaped Pd NWAs are dispersed uniformly. The diameter and length of the obtained Pd NWAs are about 50 nm and 850 nm, respectively. Furthermore, the electrocatalytic activity of Pd NWAs electrode for propanol oxidation in alkaline media has also been studied. It is found that the obtained nanostructurs exhibit excellent electrocatalytic activity toward the oxidation of propanol, demonstrating the potential application in portable direct alcohol fuel cells (DAFCs)

G2C: A Generator-to-Classifier Framework Integrating Multi-Stained Visual Cues for Pathological Glomerulus Classification

Pathological glomerulus classification plays a key role in the diagnosis of nephropathy. As the difference between different subcategories is subtle, doctors often refer to slides from different staining methods to make decisions. However, creating correspondence across various stains is labor-intensive, bringing major difficulties in collecting data and training a vision-based algorithm to assist nephropathy diagnosis. This paper provides an alternative solution for integrating multi-stained visual cues for glomerulus classification. Our approach, named generator-to-classifier (G2C), is a two-stage framework. Given an input image from a specified stain, several generators are first applied to estimate its appearances in other staining methods, and a classifier follows to combine visual cues from different stains for prediction (whether it is pathological, or which type of pathology it has). We optimize these two stages in a joint manner. To provide a reasonable initialization, we pre-train the generators in an unlabeled reference set under an unpaired image-to-image translation task, and then fine-tune them together with the classifier. We conduct experiments on a glomerulus type classification dataset collected by ourselves (there are no publicly available datasets for this purpose). Although joint optimization slightly harms the authenticity of the generated patches, it boosts classification performance, suggesting more effective visual cues are extracted in an automatic way. We also transfer our model to a public dataset for breast cancer classification, and outperform the state-of-the-arts significantly.Comment: Accepted by AAAI 201

Labeled Subgraph Entropy Kernel

In recent years, kernel methods are widespread in tasks of similarity measuring. Specifically, graph kernels are widely used in fields of bioinformatics, chemistry and financial data analysis. However, existing methods, especially entropy based graph kernels are subject to large computational complexity and the negligence of node-level information. In this paper, we propose a novel labeled subgraph entropy graph kernel, which performs well in structural similarity assessment. We design a dynamic programming subgraph enumeration algorithm, which effectively reduces the time complexity. Specially, we propose labeled subgraph, which enriches substructure topology with semantic information. Analogizing the cluster expansion process of gas cluster in statistical mechanics, we re-derive the partition function and calculate the global graph entropy to characterize the network. In order to test our method, we apply several real-world datasets and assess the effects in different tasks. To capture more experiment details, we quantitatively and qualitatively analyze the contribution of different topology structures. Experimental results successfully demonstrate the effectiveness of our method which outperforms several state-of-the-art methods.Comment: 9 pages,5 figure

Pour une approche sociolinguistique en didactique du français langue étrangère —l’argot français contemporain en classe

S’inscrivant dans une perspective de croisement entre la sociolinguistique et la didactique du FLE, cet article vise à esquisser des pistes de réflexion sur l’exploitation de l’argot français contemporain en classe. Nous nous proposons d’exposer les apprenants à la découverte de cette variété de la langue française, pour éveiller chez eux une prise de conscience de la variation stylistique et par la même occasion développer leur compétence sociolinguistique. En concevant des activités à partir des documents authentiques, nous avons fait le premier pas vers une mise en œuvre d’une approche sociolinguistique dans l’enseignement du français en Chine

Genetic and environmental influence on foliar carbon isotope composition, nitrogen availability and fruit yield of 5-year-old mango plantation in tropical Australia

The aim of this study was to quantify the effect of different varieties, planting densities, tree training systems and canopy aspect (north and south) on tree water use efficiency and nitrogen (N) availability in relation to mango fruit yield and fruit size as well as soil fertility (particularly total carbon (C) and total N as well as C and N isotope compositions) in a 5-year-old mango plantation of tropical Australia

Unveiling the nucleon tensor charge at Jefferson Lab: A study of the SoLID case

Future experiments at the Jefferson Lab 12 GeV upgrade, in particular, the Solenoidal Large Intensity Device (SoLID), aim at a very precise data set in the region where the partonic structure of the nucleon is dominated by the valence quarks. One of the main goals is to constrain the quark transversity distributions. We apply recent theoretical advances of the global QCD extraction of the transversity distributions to study the impact of future experimental data from the SoLID experiments. Especially, we develop a simple strategy based on the Hessian matrix analysis that allows one to estimate the uncertainties of the transversity quark distributions and their tensor charges extracted from SoLID data simulation. We find that the SoLID measurements with the proton and the effective neutron targets can improve the precision of the u- and d-quark transversity distributions up to one order of magnitude in the range 0.05 < x < 0.6.Comment: 11 pages, 3 figures, published on Physics Letters

Prognostic nomogram for bladder cancer with brain metastases: a National Cancer Database analysis.

BACKGROUND: This study aimed to establish and validate a nomogram for predicting brain metastasis in patients with bladder cancer (BCa) and assess various treatment modalities using a primary cohort comprising 234 patients with clinicopathologically-confirmed BCa from 2004 to 2015 in the National Cancer Database. METHODS: Machine learning method and Cox model were used for nomogram construction. For BCa patients with brain metastasis, surgery of the primary site, chemotherapy, radiation therapy, palliative care, brain confinement of metastatic sites, and the Charlson/Deyo Score were predictive features identified for building the nomogram. RESULTS: For the original 169 patients considered in the model, the areas under the receiver operating characteristic curve (AUC) were 0.823 (95% CI 0.758-0.889, P \u3c 0.001) and 0.854 (95% CI 0.785-0.924, P \u3c 0.001) for 0.5- and 1-year overall survival respectively. In the validation cohort, the nomogram displayed similar AUCs of 0.838 (95% CI 0.738-0.937, P \u3c 0.001) and 0.809 (95% CI 0.680-0.939, P \u3c 0.001), respectively. The high and low risk groups had median survivals of 1.91 and 5.09 months for the training cohort and 1.68 and 8.05 months for the validation set, respectively (both P \u3c 0.0001). CONCLUSIONS: Our prognostic nomogram provides a useful tool for overall survival prediction as well as assessing the risk and optimal treatment for BCa patients with brain metastasis