481 research outputs found

    Identification of New Resistance Sources From Diploid Wild Strawberry Against Powdery Mildew Pathogen

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    Powdery mildew pathogen causes diseases in berries and resistance breeding is hampered by the lack of sufficient sources. While control of fungal pathogens relies on chemical fungicides. In either case, a reliable source of resistance for breeding purposes is imperative for efficient protection of the crop plants. A powdery mildew isolate designated GOU1 has been identified as Podosphaera aphanis var. aphanis using light microscopy and sequencing the ITS region. Pathogenicity tests on 3 diploid wild strawberry (Fragaria vesca L.) ecotypes with GOU1 revealed 3 distinctive interaction phenotypes; enhanced susceptible (ecotype 1), intermediate susceptible (ecotype 2) and resistant (ecotype 3). In vitro staining methods with diaminobenzidine and trypan blue showed massive mycelial web and conidiophore production on the susceptible ecotype, but there was no mycelia and conidiophore production on the resistant ecotype 3. In the ecotype 3 conidiospore penetration was associated with accumulation of hydrogen peroxide production on the host cells. These findings suggest that these ecotypes could be explored as resistant gene sources to powdery mildew fungus

    Comparison of fluorgestone and medroxyprogesterone intravaginal sponges for oestrus synchronization in Saanen does during the transition period

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    The efficiency of medroxyprogesterone acetate (MAP) and fluorogestone acetate (FGA) sponges for synchronizing oestrus in lactating Saanen goats was investigated during the transition from non-breeding to natural breeding season. Does were treated for 11 days with 60 mg MAP (n=19) or 40 mg FGA (n=24) sponges. All does received intramuscular injections of 750 IU pregnant mare serum gonadotrophin (PMSG) and 125 mg cloprostenol (PGF2a) 48 h prior to sponge removal. Cervical artificial insemination (AI) with fresh diluted semen was performed at a fixed time (36 and 48 h) followed progestagen withdrawal. The two progestagen treatments showed no significant difference in oestrous response (100% both for MAP and FGA groups), time to the onset (15.8+09 and 15.0+06 h for the MAP and FGA groups, respectively), duration (30.5+1.9 and 34.0+1.4 h for MAP and FGA, respectively) and cessation (42.32+1.6 and 43.25+1.3 h for MAP and FGA, respectively) of the induced oestrus period. No significant difference was observed with respect to pregnancy rates determined at the 53rd day after AI (52.6 and 50.0% for MAP and FGA, respectively). These dates indicate that the use of MAP and FGA intravaginal progestagen treatments are equally efficient in synchronizing oestrus in lactating goats during the transition from the non-breeding to the natural breeding season. Key Words: Goat, Oestrus, Synchronization, Medroxyprogesterone acetate, MAP, Fluorogestone acetate, FGA SA Jnl Animal Sci Vol.34(1) 2004: 18-2

    The role of charged surfactants in the thermal and structural properties of lyotropic liquid crystalline mesophases of [Zn(H2O)6](NO3)2-CnEOm-H2O

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    The mixtures of [Zn(H2O)6](NO3)2 salt, 10-lauryl ether (C12H25(OCH2CH2)10OH, represented as C12EO10), a charged surfactant (cetyltrimethylammonium bromide, C16H33N(CH3)3Br, represented as CTAB or sodium dodecylsulfate, C12H25OSO3Na, SDS) and water form lyotropic liquid crystalline mesophases (LLCM). This assembly accommodates up to 8.0 Zn(II) ions (corresponds to about 80% w/w salt/(salt + C12EO10)) for each C12EO10 in the presence of a 1.0 CTAB (or 0.5 SDS) and 3.5 H2O in its LC phase. The salt concentration can be increased by increasing charged surfactant concentration of the media. Addition of charged surfactant to the [Zn(H2O)6](NO3)2-C12EO10 mesophase not only increases the salt content, it can also increase the water content of the media. The charged surfactant-C12EO10 (hydrophobic tail groups) and the surfactant (head groups)-salt ion (ion-pair, hydrogen-bonding) interactions stabilize the mesophases at such salt high and water concentrations. The presence of both Br- and NO3- ions influences the thermal and structural properties of the [Zn(H2O)6](NO3)2-C12EO10-CTAB(or SDS)-H2O LLCM, which have been investigated using XRD, POM (with a hot stage), FT-IR and Raman techniques. © 2009 Elsevier Inc. All rights reserved

    Lyotropic liquid-crystalline mesophases of [Zn(H2O) 6](NO3)2-C12EO10-CTAB- H2O and [Zn(H2O)6](NO3) 2-C12EO10-SDS-H2O systems

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    The mixture of two surfactants (C12EO10-CTAB and C 12EO10-SDS) forms lyotropic liquid-crystalline (LLC) mesophases with [Zn(H2O)6](NO3)2 in the presence of a minimum concentration of 1.75 H2O per C 12EO10. The metal ion/C12EO10 mole ratio can be increased up to 8.0, which is a record high metal ion density in an LLC mesophase. The metal ion concentration can be increased in the medium by increasing the CTAB/C12EO10 or SDS/C12EO 10 mole ratio at the expense of the stability of the LLC mesophase. The structure and some thermal properties of the new mesophase have been investigated using XRD, POM, FTIR, and Raman techniques. © 2008 American Chemical Society

    Querying industrial stream-temporal data: An ontology-based visual approach

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    An increasing number of sensors are being deployed in business-critical environments, systems, and equipment; and stream a vast amount of data. The operational efficiency and effectiveness of business processes rely on domain experts’ agility in interpreting data into actionable business information. A domain expert has extensive domain knowledge but not necessarily skills and knowledge on databases and formal query languages. Therefore, centralised approaches are often preferred. These require IT experts to translate the information needs of domain experts into extract-transform-load (ETL) processes in order to extract and integrate data and then let domain experts apply predefined analytics. Since such a workflow is too time intensive, heavy-weight and inflexible given the high volume and velocity of data, domain experts need to extract and analyse the data of interest directly. Ontologies, i.e., semantically rich conceptual domain models, present an intelligible solution by describing the domain of interest on a higher level of abstraction closer to the reality. Moreover, recent ontology-based data access (OBDA) technologies enable end users to formulate their information needs into queries using a set of terms defined in an ontology. Ontological queries could then be translated into SQL or some other database query languages, and executed over the data in its original place and format automatically. To this end, this article reports an ontology-based visual query system (VQS), namely OptiqueVQS, how it is extended for a stream-temporal query language called STARQL, a user experiment with the domain experts at Siemens AG, and STARQL’s query answering performance over a proof of concept implementation for PostgreSQL

    Two Electrons in a Quantum Dot: A Unified Approach

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    Low-lying energy levels of two interacting electrons confined in a two-dimensional parabolic quantum dot in the presence of an external magnetic field have been revised within the frame of a novel model. The present formalism, which gives closed algebraic solutions for the specific values of magnetic field and spatial confinement length, enables us to see explicitly individual effects of the electron correlation.Comment: 14 page

    Bound state solutions of the Dirac-Rosen-Morse potential with spin and pseudospin symmetry

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    The energy spectra and the corresponding two- component spinor wavefunctions of the Dirac equation for the Rosen-Morse potential with spin and pseudospin symmetry are obtained. The ss-wave (κ=0\kappa = 0 state) solutions for this problem are obtained by using the basic concept of the supersymmetric quantum mechanics approach and function analysis (standard approach) in the calculations. Under the spin symmetry and pseudospin symmetry, the energy equation and the corresponding two-component spinor wavefunctions for this potential and other special types of this potential are obtained. Extension of this result to κ0\kappa \neq 0 state is suggested.Comment: 18 page

    The impact of the COVID-19 pandemic on the learning and wellbeing of secondary school students: a survey in Southern Europe

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    The transition from the traditional model of learning and teaching to full online mode had to be implemented in many countries, in an extremely short time, as the 2020-2021 school year was in mid-stream. Secondary education, which includes students in the age range of 12-18, faced many challenges in this rapid change, as many research studies have shown. Researchers raise questions regarding the readiness of the secondary education community to transition to fully online learning. The pilot study reported in this paper deals with the impact of the transition to online learning on secondary schools in southern European countries. More specifically, this paper presents the results of a literature survey and an empirical survey using an online questionnaire which captured non-traceable responses from secondary schools that, voluntarily and anonymously, completed the questionnaire. The questions were mainly closed, with some open-ended questions for students to fill in. The study also aims to capture data on the socio-economic dimension, accessibility/ availability of the necessary technologies that enable online learning, as well as the families’ employment status and their ability to support students. A total of 90 students participated (62% female, 28% male) from three Mediterranean countries. The students’ perspectives as seen by the students themselves along with the difficulties and the issues they faced are compared and contrasted. This investigation offers a pedagogical and socio-technical analysis and highlights the needs for wellbeing as well as quality learning and teaching in the new social distance reality

    Dirac Equation with Spin Symmetry for the Modified P\"oschl-Teller Potential in DD-dimensions

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    We present solutions of the Dirac equation with spin symmetry for vector and scalar modified P\"oschl-Teller potential within framework of an approximation of the centrifugal term. The relativistic energy spectrum is obtained using the Nikiforov-Uvarov method and the two-component spinor wavefunctions are obtain are in terms of the Jacobi polynomials. It is found that there exist only positive-energy states for bound states under spin symmetry, and the energy levels increase with the dimension and the potential range parameter α\alpha.Comment: 9 pages and 1tabl
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