What is the origin of the initial inoculum for strawberry powdery mildew epidemics?

Peer reviewe

Aspect and the temporal progression in narative discourse : doctoral dissertation

Ovaj rad predstavlja diskursno istraživanje aspekta u kineskom jeziku u kontrastiranju sa srpskim jezikom. Iz ugla temporalne strukture narativnog diskursa, i na osnovu hipoteze o progresiji referentnog vremena, postulata o strukturi „istaknutosti i pozadine” narativnog diskursa i teorije retoričke strukture, istražujemo funkcionalno-semantička značenja aspekta i njegovu ulogu u izražavanju temporalne progresije (TP) u narativnom diskursu. Polazeći od karakteristika kineskog jezika, pri čemu je aspekatska kategorija predstavljena kao tročlani sistem koji čine različiti jezički izrazi (glagolske osnove, aspekatske konstrukcije, aspekatski markeri), bavićemo se aspekatskim sistemom u kome se mogu na osnovu semantičnog značenja [+ograničenost] klasifikovati dve podgrupe koje čine privativne opozicije, i to ona koja izražava ograničenu radnju i ona u čijoj je semantici odsutno ovo značenje. U okviru našeg istraživanja, putem korpusne, kvantitativne, empirijske i kontrastivne analize, detaljno se istražuju temporalno-aspekatska značenja sva tri člana aspekatskog sistema, uključujući i njihove podgrupe, klase i članove, kao i njihove korelacije i diskursne funkcije u izražavanju TP narativnog diskursa. U tom pogledu, preispituju se i sličnosti i razlike u aspekatskom izražavanju temporalne progresije između dva kontrastirana jezika. Potvrđeno je da aspekatsko značenje, odnosno, ograničenost, igra važnu ulogu u izražavanju temporalne progresije narativnog diskursa, posebno u kineskom jeziku gde ne postoji gramatička kategorija vremena. Takođe je potvrđeno da između kineskog i srpskog jezika postoji bitna razlika u načinu izražavanja aspekta, koja se ogleda prvenstveno u tome što u srpskom jeziku postoji aspekatska kategorija čije jezgro predstavlja prototipska gramatička kategorija glagolskog vida, dok u kineskom jeziku centar aspekatskog sistema predstavlja glagolski opšti aspekt, kao nemarkirani jezički izraz za aspektualnost. Gramatički aspekt u kineskom jeziku sastavljen je od nekoliko aspekatskih markera (rečca), koji opciono vrše aspekatsku modifikaciju značenja glagolske lekseme i predstavljaju markirani član aspekatskog sistema. Pored toga, ovaj rad će nastojati da pokaže da glagoli u opštem aspektu u kineskom jeziku u TP narativnog diskursa najviše pokazuju vidsku vrednost svršenih glagola u srpskom jeziku, a da su srpski semantički ekvivalenti aspekatskih konstrukcija uglavnom akciono modifikovani glagoli, kao i to da, uz iii primetno nepoklapanje kako po gramatičkom značenju, tako i po diskursnoj funkciji, ipak postoji primarna usklađenost u vidskoj vrednosti između gramatičkih aspekatskih markera u kineskom jeziku s jedne, i vidskih glagolskih oblika u srpskom jeziku s druge strane. Ovaj rad će, dakle, osim ukazivanja na razlike između predmetnih jezika, pokazati i da postoji nešto što im je zajedničko, a što se pre svega vidi u organizaciji temporalne strukture na makro nivou diskursa i drugim diskursnim principima. Sve ovo govori u prilog tezi da je, bez obzira na kom se jeziku pripovedalo, čovekovo iskustvo o narativnom vremenu slično. U pronalaženju tih sličnosti i razlika otkriva se značaj i perspektiva diskursne analize u lingvističkom istraživanju.This dissertation presents a discursive investigation of aspect in Chinese language in comparison with Serbian language. The functional-semantic meaning of aspect and its role in expressing temporal progression (TP) in narrative discourse is examined from the perspective of the temporal structure of narrative discourse, and is based on the hypothesis about the progression of the referent time, the postulate of the foregrounded-backgrounded structure of narrative discourse, as well as on the theory of rhetorical structure. Starting from the characteristics of Chinese language, with the category of aspect presented as a three-layered system comprised of language expressions of different rank (the general or lexical aspect, the aspectual constructions, and the grammatical aspect), we will deal with aspectual system where two subgroups could be delineated on the basis of semantic meaning [+boundedness], namely, the subgroup expressing bounded action, and the other whose semantics lacks this meaning. Within the framework of our research we will use statistical corpus analysis, as well as empirical and contrastive analysis for a detailed investigation of the temporal-aspectual meanings of all three layers of the aspectual system, including its subgroups, classes and members, as well as their correlations and discursive functions in expressing TP of the narrative discourse. In that regard both the similarities and the differences in aspectual expression of TP between the two contrasted languages will be investigated. It has been confirmed that the aspectual meaning, that is, the boundedness, plays an important role in TP in the narrative discourse, particularly in Chinese language in which the grammatical category of time does not exist. It has also been confirmed that there is a significant difference in the aspectual expression between the Chinese and Serbian language, which is primarily reflected in the fact that Serbian does have an aspectual category the core of which is the prototypical grammatical category of aspect, while in Chinese, the center of the aspectual system is represented by the general aspect of the verb, as an unmarked linguistic expression for aspectuality. Grammatical aspect in Chinese is made up of several aspectual markers which optionally effect the aspectual modification of the meaning of the verb’s lexeme and represent the marked members of the v aspectual system. In addition, this dissertation will endeavor to show that verbs in general aspect in Chinese in TP of narrative discourse show to the largest degree the aspectual value of perfective verbs in Serbian, and that the Serbian semantic equivalents of the aspectual constructions are predominantly the aktionsart modified verbs, as well as that, with noticeable discrepancy in both grammatical meaning and discursive function, there is nevertheless a primary correspondence in the aspectual value between, the grammatical aspectual markers in Chinese language on one hand,, and aspectual verbal forms in Serbian on the other. Therefore, in addition to pointing out the differences between the two languages in question, this dissertation will also show that they share some things in common, evident primarily in the organization of temporal structure on the macro level of discourse and in other discursive principles. All this goes to support the thesis that, no matter what is the language used to tell stories, human experience of narrative time is similar. It is in the discovery of these similarities and differences that the significance and the perspective of discursive analysis in linguistic research is revealed

Epidemiology and Control of Powdery Mildew (Podosphaera aphanis) on Strawberry

Strawberry powdery mildew, caused by Podosphaera aphanis, has the potential to cause over 20% yield loss, particularly where strawberries are grown under cover. A holistic approach to the control of strawberry powdery mildew (P. aphanis) is important, since the disease is never absent from the crop. The new disease assessment key was developed to assess strawberry powdery mildew (the old one is for assessing red blotches on leaves, See appendix 8). The results (Chapter 3) showed that the disease is present in the crop when new plants are bought in from a propagator, with 14% of strawberry crowns were infected by P. aphanis in July 2013 and 4% of the strawberry plants had symptoms of powdery mildew in pre-assessment of plants for the 2013 Si nutrient fertigation field experiment. Control measures used in one growing season reduced the disease carry-over, thus reducing the initial inoculum in the following season. The use of a late autumn fungicide spray and a fungicide spray before the plants were covered by fleece in spring reduced the number and maturity of overwintering chasmothecia, thus contributing to a reduction in initial inoculum. The use of silicon (Si) nutrient (foliar spray and root treatment) also suppressed strawberry powdery mildew development (Chapter 4). The results of Area Under Disease Progress Curve (AUDPC) and the rate of epidemic growth curve (r) in 2012 indicated that the high concentration of Si nutrient foliar spray inhibited (r = 0.002, AUDPC = 44) the epidemic build-up of P. aphanis better than the low concentration of Si nutrient (r = 0.012, AUDPC = 51) and untreated (r = 0.018, AUDPC = 70). The Si nutrient root treatment (AUDPC = 12.8) was better in inhibiting strawberry powdery mildew development than the Si nutrient foliar spray treatment. Moreover, the high concentration of Si nutrient foliar spray resulted in fewer chasmothecia compared to the untreated. Si nutrient foliar spray and root treatments increased the concentration of Si in the plants and produced physiological changes in the plants, including wax formation on the adaxial leaf surface, greater leaf thickness and cuticle layer and increased Brix0 value in plants, which all were associated with reduced disease incidence. The integrated use of all these control strategies suppresses disease development so that control is achieved with less use of conventional fungicides

Silicon enhances the constitutive defence pathway in strawberries against strawberry powdery mildew and two-spotted spider mites

Strawberry powdery mildew (Podosphaera aphanis) is a major fungal disease affecting strawberry production. The work reported here assessed the use of silicon as a nutrient (Sirius) delivered via the fertigation system in enhancing the constitutive defence pathway in strawberries, contributing to reduced susceptibility to P. aphanis and two-spotted spider mites (Tetranychus urticae Koch) in 2014 and 2015. The field trials were set up on a commercial strawberry farm in polythene tunnels at Wisbech UK between May and September in both years. Treatments were untreated control, routine commercial fungicides for P. aphanis control, 0.017% Silicon nutrient without fungicides and 0.017% Silicon nutrient plus fungicides. Percentage leaf mycelium cover and the number of T. urticae per leaf were assessed fortnightly. In both years, crops that received silicon nutrient alone had both lower rate of epidemic (r) of P. aphanis and lower value of Area Under the Disease Progress Curve (AUDPC) (r=0.0036, AUDPC=475 in 2014; r=0.001, AUDPC=267 in 2015) compared with untreated control (r=0.0042, AUDPC=662 in 2014; r=0.0011, AUDPC=281 in 2015). Silicon also delayed the epidemic build-up in the silicon nutrient alone treatment for approximately 14 days compared with untreated control. The presence of T. urticae on the leaf surface was significantly lower (P < 0.001) compared to untreated control. Other work at UH shows that the silicon nutrient enhances the constitutive defence pathway by increasing the leaf wax and cuticle thickness, and that silicon is preferentially deposited in the epidermal, palisade cells and the vascular tissue of the leaves and peduncles.Peer reviewe

Silencing of c-Ski augments TGF-b1-induced epithelial-mesenchymal transition in cardiomyocyte H9C2 cells

Background: The shRNA lentiviral vector was constructed to silence c-Ski expression in cardiac mus-  cle cells, with the aim of exploring the role of c-Ski in transforming growth factor b1 (TGF-b1)-induced epithelial-mesenchymal transitions (EMT) in H9C2 cells. Methods: Real-time polymerase chain reaction (RT-PCR) and western blot were used to detect c-Ski ex- pression at protein and messenger ribonucleic acid (mRNA) levels in 5 different cell lines. Then, lentiviral vector was constructed to silence or overexpress c-Ski in H9C2 cells. MTT and/or soft agar assay and tran- swell assay were used to detect cell proliferation and migration, respectively. The expression levels of c-Ski under different concentrations of TGF-b1 stimulation were detected by RT-qPCR and immunocytochemi- cal analysis. In the presence or absence of TGF-b1 stimulation, the proteins’ expression levels of a-SMA, FN and E-cadherin, which are closely correlated with the process of EMT, were measured by western blot after c-Ski silencing or overexpression. Meanwhile, the effect of c-Ski on Samd3 phosphorylation with TGF-b1 stimulation was investigated.  Results: There is a high expression of c-Ski at protein and mRNA levels in H9C2 cell line, which first demonstrated the presence of c-Ski expression in H9C2 cells. Overexpression of c-Ski significantly increased H9C2 cell proliferation. The ability of c-Ski gene silencing to suppress cell proliferation was gradually enhanced, and inhibition efficiency was the highest after 6 to 7 d of transfection. Moreover, H9C2 cells with c-Ski knockdown gained significantly aggressive invasive potential when compared with the control group. TGF-b1 stimulation could dose-independently reduce c-Ski expression in H9C2 cells and lead to obvious down-regulated expression of E-cadherin. Interestingly, c-Ski could restore E-cadherin expression while suppressing a-SMA and/or FN expression stimulated by TGF-b1. How- ever, shRNA-induced c-Ski knockdown aggravated only the TGF-b1-induced EMT. Moreover, c-Ski- -shRNA also promoted the phosphorylation of Samd3 induced by TGF-b1.  Conclusions: c-Ski expression in cardiac muscle cells could be down-regulated by TGF-b1. Silencing of c-Ski gene was accompanied by down-regulation of E-cadherin, up-regulation of a-SMA and/or FN and Smad3 phosphorylation induced by TGF-b1, promoting EMT process. Therefore, c-Ski may be closely associated with TGF-b1-induced EMT and play an important role in cardiac fibrosis develop- ment and progression.

Where to find lossless metals?

Hypothetical metals having optical absorption losses as low as those of the transparent insulators, if found, could revolutionize optoelectronics. We perform the first high-throughput search for lossless metals among all known inorganic materials in the databases of over 100,000 entries. The 381 candidates are identified -- having well-isolated partially-filled bands -- and are analyzed by defining the figures of merit and classifying their real-space conductive connectivity. The existing experimental evidence of most candidates being insulating, instead of conducting, is due to the limitation of current density functional theory in predicting narrow-band metals that are unstable against magnetism, structural distortion, or electron-electron interactions. We propose future research directions including conductive oxides, intercalating layered materials, and compressing these false-metal candidates under high pressures into eventual lossless metals.Comment: 36 pages, 86 figures, 3 tabl

Boosting the thermoelectric performance of p-type heavily Cu-doped polycrystalline SnSe via inducing intensive crystal imperfections and defect phonon scattering

In this study, we, for the first time, report a high Cu solubility of 11.8% in single crystal SnSe microbelts synthesized via a facile solvothermal route. The pellets sintered from these heavily Cu-doped microbelts show a high power factor of 5.57 μW cm−1 K−2 and low thermal conductivity of 0.32 W m−1 K−1 at 823 K, contributing to a high peak ZT of ∼1.41. Through a combination of detailed structural and chemical characterizations, we found that with increasing the Cu doping level, the morphology of the synthesized Sn1−xCuxSe (x is from 0 to 0.118) transfers from rectangular microplate to microbelt. The high electrical transport performance comes from the obtained Cu+ doped state, and the intensive crystal imperfections such as dislocations, lattice distortions, and strains, play key roles in keeping low thermal conductivity. This study fills in the gaps of the existing knowledge concerning the doping mechanisms of Cu in SnSe systems, and provides a new strategy to achieve high thermoelectric performance in SnSe-based thermoelectric materials