Finding the Correlation between Formative and Summative Assessments by Spearman’s Correlation Coefficient: A Case Study

Academic progresses of students are measured by using variety of statistical analysis techniques like central tendency, variability, percentiles and others. These measures help the teaching professionals to understand their student progress in their class. A relatively simple technique that can be used for exploratory data analysis is the Spearman rank correlation coefficient. In this paper the authors describe how the Spearman rank correlation coefficient can be used as a statistical tool to find out the correlation between two different types of assessments for a mathematics unit as a case study. This method is perhaps the simplest method for calculation of coefficient correlation. Is a non parametric technique for evaluating the degree of linear association or correlation between two independent variables. It is operates on the ranks of the data rather than the raw data. The case study result show that existence of a positive correlation of medium order between the formative and summative assessments. That is, increase in formative assessment the summative assessment also increase. In other words, some students who scored high in the formative assessment only managed to get medium scores in the summative assessment and vice versa

Microstructure analysis, physical and thermal properties of Al2O3-Al2TiO5 functionally graded ceramics for the application of car brake rot

Aluminium titanate (AT) (Al 2 TiO 5) is a promising engineering material because of its low thermal expansion coefficient, excellent thermal shock resistance, good refractoriness and non-wetting with most metals. Functionally graded material (FGM) is generally a particulate composite with continuously varying volume fractions. FGMs are alternative materials for dental implants, building materials and ballistic protection. It has been of great interest to future engines, internal combustion engines, metal cutting and other high temperature engineering application. There has been a demand for an adequate disc brake that requires less maintenance in the automotive manufacturing industry. FGM, the next evolution of layered structure, consists of graded compositions that are dispersed across the ceramic which produces a gradual improvement in the properties across the ceramic at a steady pace

Evaluation of energy and macronutrient intake of black women in Bloemfontein: A cross-sectional study

There is growing evidence that urbanization of black South Africans is associated with changes in the structure of dietary intake. The urban diet is more diverse than the rural diet, and includes more animalfoods, refined carbohydrates and fats, posing a potential risk to the health of urbanized populations. The objective of this cross-sectional study was to determine the macronutrient intake of non-pregnant,pre-menopausal black women living in Bloemfontein in South Africa. A representative group of 500 participants was randomly selected to participate. Women were divided into two age groups. Youngerwomen were 25 - 34 years old and older women 35 - 44 years old. Macronutrient intake was determined using a validated Quantitative Food Frequency Questionnaire (QFFQ). Median macronutrient intake was compared with the Dietary Reference Intakes (DRI) as applicable. Median energy, macronutrient and cholesterol intake of younger and older women was compared using non-parametric 95% confidenceintervals (CI’s). P-value less than 0.05 was considered significant. Median energy distribution of macronutrients was determined and compared with standard references. After being screened foreligibility, four pregnant women were excluded from the study, and 496 women qualified for participation. Median total energy, protein and carbohydrate intakes of all women exceeded the DRI. Median intakes of fibre were low, while median fat intakes were high. Younger women had significantly higher intakes of total fat (p = 0.034), saturated fat (p = 0.046) and PUFA (p = 0.015). Median energy distribution was 12% protein (both age groups), 32% fat (younger women) and 31% fat (older women) and 51% carbohydrates (younger women) and 53% carbohydrates (older women). The high median energy and macronutrient intakes may pose a potential risk for the development of chronic lifestyle diseases. The main focus of intervention should be to improve the quality of the diet, by decreasing fat intake and replacing this with fruit and vegetables. The benefits of a low glycaemic index and high fibre diet need to be emphasized

On the problem of novel composite materials development for car brake rotor

This paper presents a study of the potential materials that are suitable for the development of the automotive brake disc. Two new materials are proposed as an alternative material to the conventionally used gray cast iron for the disc brake, which are namely Metal Matrix Composite (MMC) and Functionally Graded Material (FGM). MMCs with ceramic particulate reinforcement are found to have a low density and high thermal conductivity compared to the cast irons. Two particulate reinforcements, Al2O3 and SiC were being considered for MMC. On the other hand, FGM has demonstrated high thermal shock resistance, better wear resistance and low density. Preliminary investigation indicated that MMC acquired improved hardness property. Meanwhile, the hardness property of FGM with Al2O3 and Al2TiO5 as layered composites materials can be further improved

A Computational Study of Cluster Dynamics in Structural Lubricity: Role of Cluster Rotation

We present a computational study of sliding between gold clusters and a highly oriented pyrolytic graphite substrate, a material system that exhibits ultra-low friction due to structural lubricity. By means of molecular dynamics, it is found that clusters may undergo spontaneous rotations during manipulation as a result of elastic instability, leading to attenuated friction due to enhanced interfacial incommensurability. In the case of a free cluster, shear stresses exhibit a non-monotonic dependency on the strength of the tip-cluster interaction, whereby rigid clusters experience nearly constant shear stresses. Finally, it is shown that the suppression of the translational degrees of freedom of a cluster's outermost-layer can partially annihilate out-of-plane phonon vibrations, which leads to a reduction of energy dissipation that is in compliance with Stokesian damping. It is projected that the physical insight attained by the study presented here will result in enhanced control and interpretation of manipulation experiments at structurally lubric contacts

Seed yield and agronomic parameters of cowpea (Vigna unguiculata L.) genotypes grown in the Black Sea region of Turkey

Nine cowpea (Vigna unguiculata L.) genotypes (two released cultivars and seven lines) were evaluated for grain yield and agronomic parameters at two locations within the Middle Black Sea region of Turkey for two years (2005 to 2006). Genotypes were evaluated for plant height, first pod height from ground, branches number per plant, main branch diameter, pod length, seed number per pod, thousand seed weight and seed yield. Results indicate that the effect of genotype, year and location were significant (P<0.05) for many of the traits studied. Line G1 had the highest plant height (122.4 cm). Seed number per pod was higher in line G1 (9.9) than in other genotypes. Thousand seed weight ranged between 138.7 and 233.2 g. Seed yield ranged from 1,010 to 1,420 kg ha-1. The highest seed yield (1,420 kg ha-1) was obtained in cultivar Karagoz. Among locations, average values for most variables studied were higher in Samsun than in Kavak.Key words: Vigna unguiculata, seed yield, thousand seed weight, Black Se

Some quality traits and neurotoxin β-N-oxalyl-L-α,β- diaminopropionic acid (β-ODAP) contents of Lathyrus sp. cultivated in Turkey

In this study, 52 landraces accessions belonging to the species of Lathyrus sativus and Lathyrus clymenum collected from different regions of Turkey and one released variety of Lathyrus sativus were evaluated for some quality traits like seed coat color, 1000 seed weight, crude protein and neurotoxin β- N-oxalyl-L-α,β-diaminopropionic acid (β-ODAP) content. Among the investigated landraces, high variation was determined for all the investigated traits, which was attributed to both genetic as well as environmental factors. Protein content was as between 24.07 to 30.90% and β-ODAP content was as 1.35 to 3.86 mg g-1 for seed. Many landraces with low β-ODAP content (< 2.00 mg g-1) and high protein content seem to be promising material for Lathyrus breeding. Furthermore, many investigated landraces showed lower β-ODAP and higher protein contents compared with the released variety. Also, the local consumption of L. sativus landraces as a food or feed was determined during the collection process.Key words: Lathyrus, landrace, protein, β-ODAP, Turkey

An ultrasensitive reverse transcription polymerase chain reaction assay to detect asymptomatic low-density Plasmodium falciparum and Plasmodium vivax infections in small volume blood samples.

BackgroundHighly sensitive, scalable diagnostic methods are needed to guide malaria elimination interventions. While traditional microscopy and rapid diagnostic tests (RDTs) are suitable for the diagnosis of symptomatic malaria infection, more sensitive tests are needed to screen for low-density, asymptomatic infections that are targeted by interventions aiming to eliminate the entire reservoir of malaria infection in humans.MethodsA reverse transcription polymerase chain reaction (RT- PCR) was developed for multiplexed detection of the 18S ribosomal RNA gene and ribosomal RNA of Plasmodium falciparum and Plasmodium vivax. Simulated field samples stored for 14 days with sample preservation buffer were used to assess the analytical sensitivity and specificity. Additionally, 1750 field samples from Southeastern Myanmar were tested both by RDT and ultrasensitive RT-PCR.ResultsLimits of detection (LoD) were determined under simulated field conditions. When 0.3 mL blood samples were stored for 14 days at 28 °C and 80% humidity, the LoD was less than 16 parasites/mL for P. falciparum and 19.7 copies/µL for P. vivax (using a plasmid surrogate), about 10,000-fold lower than RDTs. Of the 1739 samples successfully evaluated by both ultrasensitive RT-PCR and RDT, only two were RDT positive while 24 were positive for P. falciparum, 108 were positive for P. vivax, and 127 were positive for either P. vivax and/or P. falciparum using ultrasensitive RT-PCR.ConclusionsThis ultrasensitive RT-PCR method is a robust, field-tested screening method that is vastly more sensitive than RDTs. Further optimization may result in a truly scalable tool suitable for widespread surveillance of low-level asymptomatic P. falciparum and P. vivax parasitaemia

Low-loss slot waveguides with silicon (111) surfaces realized using anisotropic wet etching

We demonstrate low-loss slot waveguides on silicon-on-insulator (SOI) platform. Waveguides oriented along the (11-2) direction on the Si (110) plane were first fabricated by a standard e-beam lithography and dry etching process. A TMAH based anisotropic wet etching technique was then used to remove any residual side wall roughness. Using this fabrication technique propagation loss as low as 3.7dB/cm was realized in silicon slot waveguide for wavelengths near 1550nm. We also realized low propagation loss of 1dB/cm for silicon strip waveguides