3,937 research outputs found

    Written Corrective Feedback in L2 Writing : ESOL Student Attitudes about Focused and Unfocused Correction

    Get PDF
    College students in an English as a Second Language (ESOL) advanced writing and grammar course value feedback on their writing. However, grammar feedback does not tend to lead to consistent application as demonstrated by correct grammar usage in their written work. This classroom-based research study examined the students’ attitudes regarding focused and unfocused written corrective feedback (WCF) and whether their attitudes were affected by receiving focused or unfocused feedback.Twenty-two students participated in this study. The students were in two sections of an advanced writing and grammar class. Part of the students in each section received focused feedback and part received unfocused feedback. All student participants completed a pre-task questionnaire regarding their attitude toward WCF, a writing task, and a post-task questionnaire identical to the pre-task questionnaire.While the results did not show a strong preference for focused or unfocused feedback, there were two clear findings: (a) students want and appreciate feedback whether it is focused or unfocused and (b) students tended to treat all grammar mistakes of equal importance, demonstrating a need to help students notice which types of mistakes are the most important

    Optimization and Application of Chromosome In Situ Suppression Hybridization

    Get PDF
    The overall aim of this project was to develop the technique of chromosomal in situ suppression (CISS) hybridization using whole chromosome specific libraries (chromosome painting) and to apply it to the investigation of diagnostic problems in clinical cytogenetics. Initially to gain experience with non-isotopic in situ hybridization, repetitive target probes DYS59 (GMY10) and DYS58 (GMGY7) were used. This provided experience in labelling of probe with biotin, hybridization and detection conditions (alkaline phosphatase detection) and analysis of results. The technique was reliable and sensitive and was applied to map the gene for angiotensinogen to 1q42. In the later part of this initial work, a fluorescence detection technique using fluoresceinated avidin and goat biotinylated anti-avidin was applied to confirm an isochromosomes Yp and Yq using DYS59 (GMGY10) and DYS58 (GMGY7) probes. The study then progressed into the development of the chromosome painting technique. Difficulties were encountered in preparing the working library probe from the chromosome 21 specific library and a major part of the work involved solving these problems. The libraries were found to be less concentrated than indicated by the supplier. Consequently, the amplification and purification following established protocols failed to produce a concentrated DNA library in the phage. However, a good yield of the DNA library was achieved by using trypticase in the culture media and high purity agarose as the top agar during the amplification. Labelling of the library by nick-translation and random priming did not achieve decoration of the whole chromosome 21 but direct labelling of Biotin-ll-dUTP by polymerase chain reaction (PCR) amplification was found to be efficient and overcame the problem of non-homogenous painting of the target chromosome. This direct labelling approach had difficulties in the cleaning and concentration of the PCR product. These were overcome by cleaning with Sephadex G-50 column chromatography and freeze drying of eluate. Once homogeneous painting had been achieved the probe was applied for chromosome painting. Many problems and parameters for the optimum working conditions were identified in this part of study. These are either independent or/and related to various conditions involved during all stages of the technique. The maximum final concentration of the DNA mixture per slide was 10ug/10ul and increasing the ratio of the probe and/or the unlabelled DNA did not improve either the quality of suppression or the hybridization signal. Addition of human cot 1-DNA in 1 to 4 ratio with total human DNA gave better suppression. Denaturation of labelled probe and competitor DNA mixture was optimum at 75C for 8 minutes and for optimum preannealling, the mixture was prehybridized for a minimum of 60 minutes at 37C. Slides were only treated with RNase when necessary and not with Proteinase K as the latter tended to wash the cells off the slide. Denaturation of the slides was carried out at 70-75C in 70% formamide/2XSSC for a maximum of 8 minutes. At temperature of 80C the chromosome morphology was found to be distorted. Hybridization when carried out at 37C for 15 to 20 hours showed good hybridization with chromosome morphology undisturbed. Hybridization at 42-45C showed crystallization and heavy background deposits. Posthybridization washing in three changes of 50% formamide/2XSSC at 45C was found to be optimal in producing a clean background. In between detection washing using 0.1M sodium phosphate buffer with 0.1% Nonidet P-40 carried out at room temperature is sufficient to remove excess stain as compared to other washing buffers such as 2XSSC or 4XSSC containing Triton-X or Tween 20. Detection was carried out at room temperature for 15-20 minutes and any slide dried during this stage produced high autofluorescence of fluoresceinated avidin which was difficult to remove by washing. A single amplification cycle was sufficient to enhance the decoration of chromosome 21. Prebanding of slides prior to hybridization did not affect the target chromosomes, however, incomplete destaining did hinder probe penetration and interfere with counterstaining. It was found that refixing of slides (either new or old slides) in methanol:acetic acid (3:1) before denaturation tended to improve the hybridization result as well as reducing background signal. In general, the technical difficulties were related to either probe preparation, poor hybridization, non-homogeneous painting or high background but with modifications of the parameters as detailed above the method was shown to be reliable and reproducible. Chromosomes obtained from phytohaemagglutinin (PHA) stimulated blood cultures were used during the initial phase. Subsequently, painting was successfully performed on cytogenetically normal metaphase and prometaphase samples of cultured amniocytes, lymphoblastoid cell lines, chorionic villus samples (CVS) and bone marrow preparations. The results showed that all normal chromosome 21s in all types of preparation except direct chorionic villus sample (CVS) were intensely painted and distinctly recognisable. However, results with interphase nuclei were not encouraging. The signals produced were not consistent enough to produce as reliable results. Twelve cases with cytogenetic abnormalities involving the chromosome 21 were investigated using chromosome painting. These results proved that chromosome painting can be used for rapid identification of individual chromosomes and is complementary and confirmatory to conventional karyotyping and as such is predicted to have a future routine diagnostic role in clinical cytogenetics in additions to its research applications

    Homo- and Heteroleptic Copper(I) Complexes with Diazabutadiene Ligands: Synthesis, Solution- and Solid-State Structural Studies

    Get PDF
    The preparation of novel copper(I) complexes of diazabutadiene (DAB) ligands with aliphatic backbones is reported. [Cu(DABR)2](BF4), [Cu(DABR)(NCMe)2](BF4) and [CuCl(DABR)] are easily synthesised and air-stable. These complexes, which remain scarce in the literature, have been fully characterised, and their behaviour both in the solid state as well as in solution has been studied by means of X-ray crystallography, NMR and UV/Vis spectroscopy

    Does a monetary incentive improve the response to a postal questionnaire in a randomised controlled trial? : the MINT incentive study

    Get PDF
    Background: Sending a monetary incentive with postal questionnaires has been found to improve the proportion of responders, in research in non-healthcare settings. However, there is little research on use of incentives to improve follow-up rates in clinical trials, and existing studies are inconclusive. We conducted a randomised trial among participants in the Managing Injuries of the Neck Trial (MINT) to investigate the effects on the proportion of questionnaires returned and overall non-response of sending a £5 gift voucher with a follow-up questionnaire. Methods: Participants in MINT were randomised to receive either: (a) a £5 gift voucher (incentive group) or (b) no gift voucher (no incentive group), with their 4 month or 8 month follow-up questionnaire. We recorded, for each group, the number of questionnaires returned, the number returned without any chasing from the study office, the overall number of non-responders (after all chasing efforts by the study office), and the costs of following up each group. Results: 2144 participants were randomised, 1070 to the incentive group and 1074 to the no incentive group. The proportion of questionnaires returned (RR 1.10 (95% CI 1.05, 1.16)) and the proportion returned without chasing (RR 1.14 (95% CI 1.05, 1.24) were higher in the incentive group, and the overall non-response rate was lower (RR 0.68 (95% CI 0.53, 0.87)). Adjustment for injury severity and hospital of recruitment to MINT made no difference to these results, and there were no differences in results between the 4-month and 8-month follow up questionnaires. Analysis of costs suggested a cost of £67.29 per additional questionnaire returned. Conclusion: Monetary incentives may be an effective way to increase the proportion of postal questionnaires returned and minimise loss to follow-up in clinical trials

    The Application of Geographic Information System for Sustainable Land Use Planning of Central Kalimantan Province, Indonesia

    Get PDF
    Lands are scarce resources and must be optimally and sustainably utilize to satisfy the growing world population. Not all lands are suitable for agriculture purposes and this can be achieved through agroecological approach with the aid of Geographic Information System. A land use planning study on the basis of agroecological zoning was conducted in Central Kalimantan province of Indonesia.  The general methodology in this study was based on land evaluation concept.  The expert system called Land Use Program was employed to support land evaluation as general guideline for selection of agriculture system and land utilization. Land resources and climate data were then interpreted by expert system to determine zoning system for forest, perennial and annual crop, and agroforestry.  The application of geographic information (GIS) was used as database management system (DBMS) for tabular and spatial reference data as basic information of land use planning.  On the basis of land characteristics and climatic data, Central Kalimantan would be geographically divided into 7 main zones and 4 sub-zones with its zoning system within each zone or sub-zone.  The Zone I, VI, VII, and sub-zone V.2 with the total area of 4,481,300 hectares or 29.1% of total Central Kalimantan province would be allocated for forest.  The Zone II and sub-zone V.1 would be recommended for perennial crop, while zone IV (sub-zone IV1 and IV.2) would be allocated for annual crops. The total area for the perennial crop zones (II and V.1) and annual crop zones (VI) would be 6,708,400 hectares (43.6%) and 2,564,000 hectares (16.7%), respectively.  The Zone III with an area of almost 1,509,000 hectares (9.8%) would be recommended for agroforestry.  The agroecological zone approach allows efficient, effective, and optimal land utilization but for must be cautiously applied to ensure sustainable future development of Central Kalimantan. Keywords: GIS, land use planning, agroecological system, Central Kalimantan

    Wall slip and flow of concentrated hard-sphere colloidal suspensions

    Full text link
    We present a comprehensive study of the slip and flow of concentrated colloidal suspensions using cone-plate rheometry and simultaneous confocal imaging. In the colloidal glass regime, for smooth, non-stick walls, the solid nature of the suspension causes a transition in the rheology from Herschel-Bulkley (HB) bulk flow behavior at large stress to a Bingham-like slip behavior at low stress, which is suppressed for sufficient colloid-wall attraction or colloid-scale wall roughness. Visualization shows how the slip-shear transition depends on gap size and the boundary conditions at both walls and that partial slip persist well above the yield stress. A phenomenological model, incorporating the Bingham slip law and HB bulk flow, fully accounts for the behavior. Microscopically, the Bingham law is related to a thin (sub-colloidal) lubrication layer at the wall, giving rise to a characteristic dependence of slip parameters on particle size and concentration. We relate this to the suspension's osmotic pressure and yield stress and also analyze the influence of van der Waals interaction. For the largest concentrations, we observe non-uniform flow around the yield stress, in line with recent work on bulk shear-banding of concentrated pastes. We also describe residual slip in concentrated liquid suspensions, where the vanishing yield stress causes coexistence of (weak) slip and bulk shear flow for all measured rates

    Effect of Slow and Rapid Peroxidation of Corn Oil on the Performance and Energy Storage of Broiler Chicks

    Get PDF
    The extraction of corn oil from DDGS has led to an increase in the utilization of coil oil in poultry diets. This corn oil has the opportunity to undergo peroxidation during storage or processing. Therefore it is important to understand the effects of peroxidation of corn oil on growth and performance of broiler chicks. Broiler chicks were provided corn-soybean based diets containing unperoxidized corn oil (UPO), slowly peroxidized corn oil (SO; heated for 72 h at 95ᵒC), and rapidly peroxidized corn oil (RO; heated for 7 h at 185ᵒC). Corn oil was added at a 5% inclusion 0- 14 d and 10% inclusion 15-27 d. A fourth treatment consisted of a supplemental oil-free diet to be used to determine the apparent metabolizable energy nitrogen corrected (AMEn) of each corn oil diet. As expected the diets without supplemental oil resulted in reduced performance, but no significant differences were observed among oil-supplemented birds for body weight gain, feed intake, or feed conversion ratio (FCR). There was a significant difference in abdominal fat pad (AFP) weights of the broilers fed RO corn oil compared to the birds fed UPO corn oil. Analysis of samples for AMEn content is underway and will be reported shortly. Corn oil peroxidation status had minimal effects on broiler performance, but did result in differences in energy utilization as indicated by AFP weight

    Simultaneous Exposure of Different Nanoparticles Influences Cell Uptake

    Get PDF
    Drug delivery using nano-sized carriers holds tremendous potential for curing a range of diseases. The internalisation of nanoparticles by cells, however, remains poorly understood, restricting the possibility for optimising entrance into target cells, avoiding off-target cells and evading clearance. The majority of nanoparticle cell uptake studies have been performed in the presence of only the particle of interest; here, we instead report measurements of uptake when the cells are exposed to two different types of nanoparticles at the same time. We used carboxylated polystyrene nanoparticles of two different sizes as a model system and exposed them to HeLa cells in the presence of a biomolecular corona. Using flow cytometry, we quantify the uptake at both average and individual cell level. Consistent with previous literature, we show that uptake of the larger particles is impeded in the presence of competing smaller particles and, conversely, that uptake of the smaller particles is promoted by competing larger particles. While the mechanism(s) underlying these observations remain(s) undetermined, we are partly able to restrain the likely possibilities. In the future, these effects could conceivably be used to enhance uptake of nano-sized particles used for drug delivery, by administering two different types of particles at the same time

    Assessment of Internet Service Provided using UMTS operators at the University of Ilorin main campus

    Get PDF
    Over the years the need for mobile broadband had seen a great increment due to the demand of internet mobile users. In this research work, data size for Internet operation on UMTS mobile network operators on the University of Ilorin Campus was assessed. The study assessed three UMTS network operators using an Infinix T627 android smart phone and RantCell App. to measure the download and upload at the selected points on the University of Ilorin Campus. It was observed that the number of active subscribers with their relative position in a cell have a great effect on the performance of the networks and therefore, the authors recommend the need for the operators to improve their data sizes so as to enhance users’ satisfaction. Keywords: GSM, CDMA, ISP, PS, UMTS
    corecore