Empirical evidence has shown that visually enhancing the saliency of reward probabilities can ease the cognitive demands of value comparisons and improve value-based decisions in old age. In the present study, we used a time-varying drift diffusion model that includes starting time parameters to better understand (1) how increasing the saliency of reward probabilities may affect the dynamics of value-based decision-making and (2) how these effects may interact with age. We examined choices made by younger and older adults in a mixed lottery choice task. On a subset of trials, we used a colorcoding scheme to highlight the saliency of reward probabilities, which served as a decision-aid. The results showed that, in control trials, older adults started to consider probability relative to magnitude information sooner than younger adults, but that their evidence accumulation processes were less sensitive to reward probabilities than that of younger adults. This may indicate a noisier and more stochastic information accumulation process during value-based decisions in old age. The decision-aid increased the influence of probability information on evidence accumulation rates in both age groups, but did not alter the relative timing of accumulation for probability versus magnitude in either group.

Flax (Linum usitatissimum L.) is a self-pollinated crop widely cultivated for fiber and oil production. Flaxseed is renowned for its health attributes but the presence of compounds, such as the heavy metal cadmium (Cd), is undesirable. Genomic studies in flax have produced large amounts of data in the last 15 years, providing useful resources to improve the genetic of this crop using genomics-based technologies and strategies. The goal of this thesis is therefore to capitalize on these advances to address the Cd problem and to propose solutions to improve breeding efficiencies. To find genomic-based solutions to Cd content, to the currently low breeding efficiency and to abiotic stress resistance in flax, this study utilized four major strategies: (1) genomic cross prediction, (2) gene family identification, (3) genome-wide association study (GWAS) and (4) genomic selection (GS). Characterization of the ATP-binding cassette (ABC) transporter and heavy metal associated (HMA) gene families was performed using the flax genome sequence. A total of 198 ABC transporter and 12 HMA genes were identified in the flax genome, of which nine were orthologous to Cd-associated genes in Arabidopsis, rice and maize. A transcriptomic analysis of eight tissues provided some support towards the functional annotation of these genes and confirmed the expression of these ABC transporter and HMA genes in flax seeds and other tissues. A diversity panel of 168 flax accessions was grown in the field at multiple locations and years and the seed content of 24 heavy metals (HMs) was measured. The panel was also sequenced and a single nucleotide polymorphism (SNP) dataset of nearly 43,000 SNPs was defined. A GWAS was conducted using these genotypic and phenotypic data and a total of 355 non-redundant quantitative trait nucleotides (QTNs) were identified for ten of the 24 metal contents. Overall, a total of 24 major and 331 minor effect QTNs were detected, including 11 that were pleiotropic. After allelic tests, 108 non-redundant QTNs were retained for eight of the ten metals and ranging from one for copper (Cu) to 70 for strontium (Sr). A total of 20 candidate genes for HM accumulation were identified at 12 of the 24 major QTN loci, of which five belonged to the ABC transporter family. Many of the metal contents, including Cd, appeared to be controlled by many genes of small effects; hence, GS is better suited than marker-assisted selection for application in breeding. To test this, predictive ability using ten GS statistical models was evaluated using trait-specific QTN and the random genome-wide 43K SNP datasets. Significantly higher predictive abilities were observed from the GS models built with the dataset made of QTNs associated with metal contents (70-80%) compared to that of the 43K dataset (10-25%). This study showed the feasibility of using GS to improve the predictive ability of polygenic traits such as metal content in seeds. GS can be applied in early generation selection to accelerate the improvement of abiotic stress resistance and either select low-Cd lines or discard high-Cd lines. These findings validate the use of a QTL-based strategy as a highly effective method for improving the efficiency of predictive ability of GS for highly complex traits such as resistance or tolerance to HM accumulation. Identification of both large and minor effect QTNs and/or pleiotropic effects hold potential for flax breeding improvement. Candidate gene functional validation can be performed using methods such as genome editing or targeting induced local lesions in genomes (TILLING).

In Cam Pha city (Quang Ninh province) there existes a lot of vegetation having a high degree of degradation. Findings of the research plots located in 4 years (2012-2015) have shown that, vegetation IC has the largest biomass (biomass fresh: 78.70 tons / ha; dry biomass: 36.65 tons / ha), followed by the grass vegetation (fresh biomass: 62.08 tons / ha; dry biomass: 25.67 tons / ha ). Vegetation IA has the lowest biomass (biomass fresh: 33.73 tons / ha; dry biomass: 15.18 tons / ha). The average amount of accumulated carbon in the biomass of vegetation IC is 18.33 tones / ha, in that vegetation IA was 7.60 tones/ ha, in the grass vegetation is 12.84 tones / ha. During the ecological succession, vegetation IC showed an increase in the ability to accumulate carbon (the amount of biomass carbon accumulation of vegetation IC in the 4th year was 21.97 tons / ha). In addition, the paper also proposed the suitable methods of using degraded vegetation in Cam Pha city, Quang Ninh province. / Ở thành phố Cẩm Phả, tỉnh Quảng Ninh tồn tại nhiều thảm thực vật có mức độ thoái hóa cao. Kết quả nghiên cứu trong các ô nghiên cứu định vị trong 4 năm (2012 - 2015) cho thấy, thảm cây bụi IC có sinh khối lớn nhất (sinh khối tươi: 78,70 tấn/ha; sinh khối khô: 36,65 tấn/ha), tiếp đến là thảm cỏ (sinh khối tươi: 62,08 tấn/ha; sinh khối khô: 25,67 tấn/ha). Thảm cây bụi IA có sinh khối thấp nhất (sinh khối tươi: 33,73 tấn/ha; sinh khối khô: 15,18 tấn/ha). Giữa các thảm thực vật này còn khác nhau về cấu trúc sinh khối và tỷ lệ sinh khối khô / sinh khối tươi. Lượng cacbon trung bình được tích lũy trong sinh khối của thảm thực vật cây bụi IC là 18,33 tấn/ha, ở thảm cây bụi IA là 7,60 tấn/ha, ở thảm cỏ là 12,84 tấn/ha. Trong quá trình diễn thế, thảm cây bụi IC có sự tăng lên về khả năng tích lũy cacbon (Lượng cacbon được tích lũy trong sinh khối của thảm cây bụi IC ở năm thứ 4 là 21,97 tấn/ha). Ngoài ra, bài báo còn đề xuất phương thức sử dụng hợp lý các thảm thực vật thoái hóa ở thành phố Cẩm Phả, tỉnh Quảng Ninh.

No description available.

No description available.

No description available.

No description available.

The emerging evidence of preferential accumulation and long residence time of proteinaceous compounds in soil are counter to the traditional view that their structure is readily broken down through microbial activity. The shift in thinking of their residence time is, however, heavily influenced by physical and chemical protections in soil, representing an important change for understanding global biogeochemical carbon and nitrogen cycling. We investigated the accumulation patterns of proteinogenic amino acids for a long term (thousands of years) related to their sources and sinks. We found clear patterns of change in the amino acids in a 4000 year-chronosequence adjacent to Lake Michigan, USA (Michigan chronosequence) and they were tightly related to the shifts in their biological sources, namely aboveground vegetative community (r2=0.66, p<0.0001) and belowground microbial community (r2=0.71, p<0.0001). Results also showed great variations of approximately 49% between seasons (summer and winter). Moreover, seasonal dynamic patterns (22% variations) of the amino acids in soil mineral associated fraction were rather counter to the conceptual view that it represents a slow soil organic pool with long residence times. The amino acids enriched in the mineral associated fraction, (e.g., positively charged, aromatic, and sulfur containing amino acids), tended to preferentially accumulate in whole soil pool during the 4000 years of ecosystem development. Their interaction with soil minerals, therefore, may play a critical role in the long-term sink and selective accumulation of proteinaceous compounds with some degree of the displacement. This was further confirmed by another chronosequence system near Haast River, New Zealand, which is geologically separated and climatically- and ecologically- different from the Michigan chronosequence. Common trends between two chronosequences suggested that either polar interactions or redox reactions may be relatively more important in the mineral interaction of amino acids than non-polar interactions. The consistency of results at two disparate locations in the southern and northern hemispheres is strong evidence that the processes of pedogenesis and ecosystem development are parsimonious and predictable. Our research demonstrated fundamental understanding of behavior of proteinaceous compounds at the molecular species level, and further provided their partitioning mechanisms associated with soil components. / Ph. D.

Ziel der vorliegenden Arbeit war es, den Einfluss verschiedener Schwefel (S)-Düngemittel, der Leguminosenart und des Gemengebaus von Erbse (Pisum sativum L.) und Gerste (Hordeum vulgare L.) auf die Schwefelakkumulation sowie den Ertrag der Ackerbohne (Vicia faba L.), Schmalblättrige Lupine (Lupinus angustifolius L.) und Erbse zu erheben. In den Jahren 2012 bis 2014 wurden Feldversuche auf zahlreichen Standorten durchgeführt, um die Wirkung von Kieserit (MgSO4), Gips (CaSO4), elementarem S und Bittersalz (MgSO4 × 7H2O) auf die Körnerleguminosen zu testen. Die Düngung von Ackerbohne, Schmalblättriger Lupine und Erbse mit verschiedenen S-haltigen Düngemitteln führte unter den geprüften Feldbedingungen weder zu Ertragssteigerungen noch zu einer gesteigerten N-Akkumulation. Der S-Bedarf der drei Körnerlegunminosen wurde offenbar über natürliche Ressourcen gedeckt. Trotzdem zeigten sich Gips und Kieserit, teilweise auch Bittersalz als geeignete Düngemittel, um die S-Konzentration im Gewebe der Pflanzen zu erhöhen. Die S-Akkumulation im Spross der Ackerbohne (5-17 kg S ha-1), Schmalblättrigen Lupine (5-15 kg S ha-1) und Erbse (2-13 kg S ha-1) war gering und wurde von den Pflanzen an deren Bedarf angepasst. Im Gegensatz zu Ackerbohne (SHI 0,65) und Erbse (SHI 0,63), die S vorwiegend im Korn akkumulierten, sammelte die Schmalblättrige Lupine einen Großteil des aufgenommenen S im Stroh (SHI 0,40) an. Der Einfluss des Gemengeanbaus mit Gerste auf den S-Haushalt der Erbse war sehr gering. Die Erbse in Reinsaat nahm signifikant mehr S gemittelt über alle getesteten Düngemittel auf als das Gemenge aus Erbse und Gerste. Erbse und Gerste akkumulierten ähnlich hohe Mengen S im Spross pro Einheit Kornertrag. Um maximale Kornerträge sowie N- und S-Akkumulationen in einem substitutiv zusammengesetzten Gemenge aus Erbse und Gerste zu erzielen, wurde ein optimales Saatverhältnis von 42-88% keimfähiger Erbsensamen zu 12-58% keimfähigen Gerstensamen der jeweiligen Reinsaatstärke ermittelt. / The objectives of this study were to evaluate the influence of different sulfur (S) containing fertilizers, the legume species and of intercropping of pea (Pisum sativum L.) and barley (Hordeum vulgare L.) on sulfur accumulation and yield of faba bean (Vicia faba L.), narrow leaf lupin (Lupinus angustifolius L.) and pea. In the years 2012 to 2014 field trials have been conducted to test the effects of kieserite (MgSO4), gypsum (CaSO4), elemental S and epsom salt (MgSO4 × 7H2O) on grain legumes at several sites in Germany. Under the given environmental conditions, fertilization of faba bean, narrow leaf lupin and pea with different S containing fertilizers did not increase yield and nitrogen (N) accumulation. The S demand of the three grain legumes was low and obviously covered by S sources from the soil as well as atmospheric S deposition. However, gypsum, kieserite and epsom salt generated noticeable increases in S concentration in parts of the plants. S accumulation in shoots of faba bean (5-17 kg S ha-1), narrow leaf lupin (5-15 kg S ha-1) and pea (2-13 kg S ha-1) was comparatively low and has been adapted to the plants respective S demand. In contrast to faba bean (SHI 0,65) and pea (SHI 0,63), who accumulated S predominantly in seeds, narrow leaf lupin (SHI 0,40) accumulated the bulk of S in its straw. The influence of barley on peas S concentration was very low. Pea in pure stands accumulated significantly more S than the total intercrop of pea and barley, whereas pea and barley accumulated similar amounts of S in its shoots per unit seed yield. To achieve the maximum seed yield and maximum N and S accumulation in substitutive mixtures of pea and barley, a relative seed frequency of 42%–88% pea seeds to 12%–58% barley seeds of their monocrop seeding rate has been calculated to be optimal.

The distribution and potential sources of 15 polycyclic aromatic hydrocarbons (PAHs) in soils and Digitaria eriantha in the vicinity of three South African coal-fired power plants, Matla, Lethabo and Rooiwal were determined by gas chromatography–mass spectrometry. An ultrasonic assisted dispersive liquid-liquid microextraction (UA-DLLME) method was developed for the extraction of polycyclic aromatic hydrocarbon in soil, followed by determination using gas chromatography mass spectrometry. The study showed that an extraction protocol based on acetonitrile as dispersive solvent and C2H2Cl2 as extracting solvent, gave extraction efficiencies comparable to conventional soxhlet extraction for soil samples. The extraction time using ultrasonication and the volume of the extraction solvent was also investigated. Using a certified reference material soil (CRM), the extraction efficiency of UA-DLLME ranged from 64 to 86% in comparison with the Soxhlet result of 73 to 95%. In comparison with the real sample, the CRM result did not show a significant difference at 95% C.I. The UA-DLLME proved to be a convenient, rapid, cost-effective and greener sample preparation approach for the determination of PAHs in soil samples. PAH compound ratios such as phenanthrene/phenanthrene + anthracene (Phen/ Phen + Anth) were used to provide a reliable estimation of emission sources. The total PAH concentration in the soils around three power plants ranged from 9.73 to 61.24 μg g−1, a range above the Agency for Toxic Substances and Disease Registry levels of 1.0 μg g−1 for a significantly contaminated site. Calculated values of the Phen/Phen + Anth ratio were 0.48±0.08, 0.44±0.05, and 0.38+0.04 for Matla, Lethabo and Rooiwal, respectively. The flouranthene/fluoranthene + pyrene (Flan/ Flan + Pyr) levels were found to be 0.49±0.03 for Matla, 0.44±0.05 for Lethabo, and 0.53±0.08 for Rooiwal. Such values indicate a xx pyrolytic source of PAHs. Higher molecular weight PAHs (five to six rings) were predominant, suggesting coal combustion sources. The carcinogenic potency B[a]P equivalent concentration (B[a] Peq) at the three power plants ranged from 3.61 to 25.25, indicating a high carcinogenic burden. The highest (B[a] Peq) was found in samples collected around Matla power station. It can, therefore, be concluded that the soils were contaminated with PAHs originating from coal-fired power stations. Nine metals (Fe, Cu, Mn, Ni, Cd, Pb, Hg, Cr and Zn) were analysed in soil and the Digitaria eriantha plant around three coal power plants (Matla, Lethabo and Rooiwal), using ICP-OES and GFAAS. The total metal concentration in soil ranged from 0.05 ± 0.02 to 1835.70 ± 70 μg g-1, 0.08 ± 0.05 to 1743.90 ± 29 μg g-1 and 0.07 ± 0.04 to 1735.20 ± 91 μg g-1 at Matla, Lethabo and Rooiwal respectively. The total metal concentration in the plant (Digitaria eriantha) ranged from 0.005 ± 0.003 to 534.87 ± 43 μg g-1 at Matla, 0.002 ± 0.001 to 400.49 ± 269 μg g-1 at Lethabo and 0.002 ± 0.001 to 426.91 ± 201 μg g-1 at Rooiwal. The accumulation factor (A) of less than 1 (i.e. 0.003 to 0.37) at power plants indicates a low transfer of metal from soil to plant (excluder). The enrichment factor values obtained (2.4 – 5) indicate that the soils are moderately enriched, with the exception of Pb that had significant enrichment of 20. The Geo-accumulation Index values of metals indicate that the soils are moderately polluted (0.005 – 0.65), except for Pb that showed moderate to strong pollution (1.74 – 2.53). / Chemistry / D. Phil. (Chemistry)