252 research outputs found

    The Development of Science-Biology Learning Instrument Oriented to Mangrove Forest for Junior High School Students

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    This research aims to develop a science-biology learning instrument that is practical and effective. The stage of development using procedural model consisting of: a) the identification of problem, b) describes the objectives, and c) establishes the development model. The stage of products testing included: a) test, b) to evaluate, and c) communicate the results. The subjects were students of SMPN 3 and 5, Loban River, Tanah Bumbu regency. Individual testing was done in SMPN3. Small group and field test was conducted in SMPN 5. The data of practicality of learning instruments includes: a) the USAge of lesson plan (RPP), and b) the response of students to learning process. The data of effectiveness of learning instruments includes: a) the cognitive learning outcomes, b) the assessment results of critical thinking skills, c) the assessment results of behavioral characteristics, d) the assessment results of social skills, and e) the effectiveness of students in learning process. Data were collected through tests and observation and analyzed descriptively. The results of research in the development stage, including: a) problem identification such as topic selection of learning and the determination of learning environment, b) learning objectives based on the ABCD rule and learning outcomes, such as critical thinking skills, c) development model. The research results in the testing product stage demonstrated the practicality of the learning instrument has been reached. It is based on: a) the USAge of RPP which were already good, and b) most students have responded positively to the learning process. The effectiveness of learning intrument has also been fulfilled. It is based on: a) cognitive learning outcomes that have been completed, b) the assessment results of critical thinking skills, behavioral characteristics, and social skills, that have achieved good category, e) the student's liveliness in learning process which were already visible

    The efficacy of the period of saccharification on oil palm (Elaeis guineensis) Trunk sap hydrolysis

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    © IJTech 2018. This study investigates the enzymatic hydrolysis rate of Oil Palm (Elaeis guineensis) Trunk (OPT) sap in terms of the length of saccharification process with the aim to elevate sugar production. Emphasis was placed on the reaction time and addition of supplements such epsom salt (MgSO4) and alanine amino acid (C3H7NO2) to accelerate the efficiency of Saccharomyces cerevisiae containing the enzyme invertase. A whole oil palm trunk was divided into four different sections, upper, middle-1, middle-2 and bottom with separate experiments over 10 days enzymatic reaction period. The highest saccharification rate was shown as 13.47% on the tenth day. This result indicates that the increase in the saccharification rate was positively correlated with the length of hydrolysis. Moreover, the sample with nutrients achieved the highest sugar output, 17.91% on the fourth day of hydrolysis which was 4.44% higher than the hydrolysis rate of the sample without nutrients. In the presence of complex OPT sugars, together with other essential elements, epsom salt and alanine amino acid, S.cerevisiae achieved a higher hydrolysis metabolism to simple sugars as the cells strived to produce energy and regenerated the invertase. Moreover, the upper part of the OPT rendered the highest potential for sugar production with levels of 21.2% with supplements and 15.6% without. From this experimental analysis, a conventional saccharification method was optimized through the addition of nutrients and a prolonged (10 days) hydrolysis process which yielded an increase in sugar production

    Wetting of compacted clays under laterally restrained conditions:initial state, overburden pressure and mineralogy

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    International audienceCompacted clay fills are generally placed at the optimum value of water content and, immediately after placement, they are unsaturated. Wetting might subsequently occur due, for example, to rainfall infiltration, which can cause volumetric deformation of the fill (either swell or collapse) with associated loss of shear strength and structural integrity. If swelling takes place under partially restrained deformation, due for example to the presence of a buried rigid structure or a retaining wall, additional stresses will develop in the soil and these can be detrimental to the stability of walling elements and other building assets. Factors such as dry density, overburden pressure, compaction water content and type of clay are known to influence the development of stresses. This paper investigates these factors by means of an advanced stress path testing programme performed on four different clays with different mineralogy, index properties and geological histories. Specimens of kaolin clay, London Clay, Belfast Clay and Ampthill Clay were prepared at different initial states and subjected to `controlled' wetting, whereby the suction was reduced gradually to zero under laterally restrained conditions (i.e. K0 conditions). The results showed that the magnitude of the increase in horizontal stresses (and therefore the increase of K0) is influenced by the overburden pressure, compaction water content, dry density at the time of compaction and mineralogy

    Grapevine xylem sap enhances biofilm development by Xylella fastidiosa

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    Xylella fastidiosa is able to form biofilms within xylem vessels of many economically important crops. Vessel blockage is believed to be a major contributor to disease development caused by this bacterium. This report shows that Vitis riparia xylem sap increases growth rate and induces a characteristic biofilm architecture as compared with biofilms formed in PD2 and PW media. In addition, stable cultures could be maintained, frozen and reestablished in xylem sap. These findings are important as xylem sap provides a natural medium that facilitates the identification of virulence determinants of Pierce's diseas

    Twitching motility and biofilm formation are associated with tonB1 in Xylella fastidiosa

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    A mutation in the Xylella fastidiosa tonB1 gene resulted in loss of twitching motility and in significantly less biofilm formation as compared with a wild type. The altered motility and biofilm phenotypes were restored by complementation with a functional copy of the gene. The mutation affected virulence as measured by Pierce's disease symptoms on grapevines. The role of TonB1 in twitching and biofilm formation appears to be independent of the characteristic iron-uptake function of this protein. This is the first report demonstrating a functional role for a tonB homolog in X. fastidios

    Distinct roles for the IIId2 sub-domain in pestivirus and picornavirus internal ribosome entry sites.

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    Viral internal ribosomes entry site (IRES) elements coordinate the recruitment of the host translation machinery to direct the initiation of viral protein synthesis. Within hepatitis C virus (HCV)-like IRES elements, the sub-domain IIId(1) is crucial for recruiting the 40S ribosomal subunit. However, some HCV-like IRES elements possess an additional sub-domain, termed IIId2, whose function remains unclear. Herein, we show that IIId2 sub-domains from divergent viruses have different functions. The IIId2 sub-domain present in Seneca valley virus (SVV), a picornavirus, is dispensable for IRES activity, while the IIId2 sub-domains of two pestiviruses, classical swine fever virus (CSFV) and border disease virus (BDV), are required for 80S ribosomes assembly and IRES activity. Unlike in SVV, the deletion of IIId2 from the CSFV and BDV IRES elements impairs initiation of translation by inhibiting the assembly of 80S ribosomes. Consequently, this negatively affects the replication of CSFV and BDV. Finally, we show that the SVV IIId2 sub-domain is required for efficient viral RNA synthesis and growth of SVV, but not for IRES function. This study sheds light on the molecular evolution of viruses by clearly demonstrating that conserved RNA structures, within distantly related RNA viruses, have acquired different roles in the virus life cycles

    Hydrogen adsorption capacity using modified nickel-kenaf core at different concentrations

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    In this study, surface chemistry modification of kenaf adsorbent in adsorptive hydrogen storage system was computationally investigated using Brunauer-Emmett-Teller (BET) surface area, thermogravimetric analysis (TGA), field emission scanning electron microscopy (FESEM), and elemental dispersion X-ray (EDX) analysis, in which the suitability of the adsorbent was determined with detailed physicochemical characterisation analysis. The method used for surface modification was metal deposition method using Ni(NO3)2 with various concentrations at different levels of pressure (up to 6 bars). Based on this research, modified kenaf with 0.4 M Ni(NO3)2 and 2.559 m2 g-1 adsorbed up to 1.013 mmol g-1 of hydrogen compared to the raw kenaf with only 0.396 mmol g-1 of hydrogen adsorbed in 5 h. Two consecutive cycles of adsorption were carried out to show the delivery performance of hydrogen adsorptive storage. Thus, different adsorption ability between the modified kenaf and raw kenaf shows that Ni-metal on kenaf surface assists in hydrogen adsorption process

    Rainfall induced residual soil slope instability: building cracked and slope failure

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    Rainfall is one of the factors of slope failures due to the intensity of rainfall that will seep and increase the moisture content of geo-materials. One of the important role in slope stability is matric suction. This study present the relationship between rainfall and suction of soil which induced the slope instability and the slope stability analysis involving a building which may cause by instability due to suction variation. The slope had separated into three parts which are top of slope, middle of slope and toe of slope. Every part has been inserted with three tensiometer with 0.3 m, 0.45 m and 0.9 m depth. Suction of soil on slope was carried out by using tensiometer. Intensity of rainfall was collected by using rain gauge which placed at open area which to compare with matric suction of soil. Several site and laboratory tests were carried out to identify the soil properties. Stability of slope was analyzed using Slope/w and Manual Calculation via input parameters collected from laboratory test and field test. Fellenius’ method was used to interpret the factor of safety for slope study. This includes the analysis of the factor of safety of slices at the selected area with its matric suction value. It was found that when the rainfall increased, the suction of soil decreased and affected to decrease of factor of safety. Hence, the constructed slope was suggested to be redesign to improve its safety factor

    Granite Exploration by using Electrical Resistivity Imaging (ERI): A Case Study in Johor

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    Electrical Resistivity Imaging (ERI) is a tool used in near surface geophysical surveys by flowing an electric current through electrodes that were injected into the ground. The usage of electrical resistivity imaging (ERI) method dominated by geophysicist has increased tremendously in geotechnical engineering application owing to the efficiency and effectiveness of the method in term of time, cost and also data coverage. The survey performed with respect to the particular reference to ERI in determining the granite rock underneath the ground. There were seven (7) lines of ERI performed at the study area by using ABEM Terrameter LS 2 set of equipment based on Schlumberger protocol. Six (6) boreholes were also drilled to obtain engineering properties of rock at the study area. In order to develop the relationship between resistivity and engineering properties, a comparison between borehole field test result and the resistivity value were made. Results from the ERT indicated the presence of zones with high resistivity values identified as overburden soil, fractured granite and solid granite. The findings of this study also showed that the electrical resistivity imaging coupled with borehole drillings were applicable tools for the determination of the granite rock underneath the ground via subsurface profiles and such as depth of overburden soil and engineering properties of soil

    The DREEM, part 1: measurement of the educational environment in an osteopathy teaching program

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    Background Measurement of the educational environment has become more common in health professional education programs. Information gained from these investigations can be used to implement and measure changes to the curricula, educational delivery and the physical environment. A number of questionnaires exist to measure the educational environment, and the most commonly utilised of these is the Dundee Ready Educational Environment Measure (DREEM). Methods The DREEM was administered to students in all year levels of the osteopathy program at Victoria University (VU), Melbourne, Australia. Students also completed a demographic survey. Inferential and correlational statistics were employed to investigate the educational environment based on the scores obtained from the DREEM. Results A response rate of 90% was achieved. The mean total DREEM score was 135.37 (+/- 19.33) with the scores ranging from 72 to 179. Some subscales and items demonstrated differences for gender, clinical phase, age and whether the student was in receipt of a government allowance. Conclusions There are a number of areas in the program that are performing well, and some aspects that could be improved. Overall students rated the VU osteopathy program as more positive than negative. The information obtained in the present study has identified areas for improvement and will enable the program leaders to facilitate changes. It will also provide other educational institutions with data on which they can make comparisons with their own programs
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