Variable Grade Research Articles

Suitability of various benthic biotic indices in assessing the coastal ecological quality in Fujian Province, China

Three benthic biotic indices, AZTI marine biotic index (AMBI), benthic opportunistic polychaetes amphipods (BOPA), and benthic polychaetes amphipods (BPA), combined with Shannon diversity index (H) were applied in ecological quality status (EQS) assessment, to investigate their suitability at four bays and an estuary in Fujian Province. The results showed that there were substantial differences in the performance of these indices. There were only four sites with the same assessment grades using different indices, accounting for 8.7% of the applied sites. AMBI classified 76.1% of the sites as "Good", while 89.1% of the sites were classified as "High" using BOPA. The assessment results of BPA and H showed obvious gradient changes. For the bay areas, all the BOPA, BPA and AMBI values had no significant correlation with dissolved inorganic phosphate (DIP) and dissolved inorganic nitrogen (DIN) concentrations, suggesting that these indices did not respond to eutrophication pressure. The H value was significantly and negatively correlated with DIN concentration. For the estuarine area, the three indices, i.e . BOPA, BPA and AMBI, had significantly positive correlations with DIN and DIP, and there was no clear spatial variation in the assessment grades of these indices with the distance toward sea. The results suggested that BOPA, BPA and AMBI would overestimate the EQS and would show no response to the eutrophication pressure in estuarine area. Similar to the result from the bay areas,H value in the estuary area was significantly and negatively correlated to DIN. Meanwhile, the assessment grades of the seven sections in the estuary tended to increase with the distance toward the sea. In summary, our results suggested that BOPA, BPA and AMBI would not be suitable for the EQS assessment for Fujian coastal area, while H would be more suitable as it could respond to the main anthropogenic pressures.

Inter-observer agreement of soft contact lens fit assessment

Purpose: Soft contact lens fit assessment and recording varies among clinicians. The aim of this study is to compare the inter-student variation in contact lens grading using two scales, a traditional scale (using mm or % estimation) and a three point grading scale. Methods: Forty-four second year optometry students with 10 weeks of contact lens experience participated in this study evaluating 6 different lens fits of daily and reusable commercially available soft contact lenses. Students evaluated up-gaze blink, push-up (displacement) and horizontal lag and were randomly assigned to use the traditional or three point grading scale. Students were briefed prior to the study to ensure scale interpretation consistency. The study was time-controlled and after a 3-minute slit-lamp set-up, students received 1-minute for the measurement of each aspect of the fit. Results: Inter-observer agreement was assessed using: a) concordance and 95% confidence intervals of paired observations and b) intra-class correlation (ICC) statistic. The three-point scale showed a higher concordance than the traditional scale for all but the horizontal lag measurement (up-gaze blink 32% vs 11%, push-up 43% vs 11% and horizontal lag 36% vs 43%). The 95% confidence intervals for the traditional scale were narrower than that of the three-point scale (up-gaze blink 0.4mm vs 1.8, push-up 43% vs 1.8 and horizontal lag 0.3mm vs 1.9). The ICC was higher for the traditional scale (horizontal lag 0.42 vs 0.28 and push-up 0.49 vs 0.20) but slightly lower than the three-point scale for the blink in up-gaze (0.77 vs 0.88). Conclusions: Overall, the three point scale showed higher concordance indicating higher agreement between randomly paired student observations. However, the 95% confidence interval was wider as compared to the traditional scale reducing the ability to detect clinical change. Thus, our results suggest that the traditional scale is preferable during Optometrist’s training.

Determination of Agarwood volatile compounds from selected Aquilaria species plantation extracted by Headspace-Solid Phase Microextraction (HS-SPME) method

A collection of inoculated heartwood of three Aquilaria species namely A. crassna, A. sinensis and A. subintegra were investigated for their volatile compounds. The volatile compounds were extracted using automated Headspace-Solid Phase Microextraction (HS-SPME) with fibre coating of 50/30 µm divinyl benzene/carboxen/poly-dimethylsiloxane (DVB/CAR/PDMS) and determined by gas chromatography/mass spectrometry (GCMS). The absence of proper scientific method in forming the agarwood has resulted in variations in agarwood quality and inconsistent grades in the market. Thus there is a need to quantify the amount of major volatile compounds found in the agarwood so that the quality can be scientifically verified. In this study, the commonly known volatile compounds present in agarwood sample were found but with varying amounts. At least three important compounds were obtained i.e. β-agarofuran, α-eudesmol and agarospirol. Based on the presence of these main volatile compounds, the study suggests that extraction by HS-SPME also useful instead of distillation process. The ability to identify key components in a short time can facilitate and shorten the analysis time. It further helps in developing the quality of agarwood industry standards.

Agility in the Factors Effecting the Quality and Safety of Fish Products

The consumption of fish by humans worldwide is 77%. The demand and consumption of fresh fish has significantly grown during recent years. The future growth is from aquaculture as the global demand for fish continuous to increase. The supply chain of fish is a network which consists of the fishermen, middlemen, distributors, transporters, storage facilities, suppliers, retailers, delivery and selling the product to the consumer. It is necessary to maintain the quality and safety of fish/fish products till the time of consumption by the consumer. The quality and safety of the fish/ fish products may deteriorate due to variations in temperature, distribution channel, transportation, packaging and grading. The purpose of this paper is to understand the impact of these factors on the quality and safety of the fish/fish products and to propose the implementation of the concept of agility into these factors so that the quality and safety of these products is ensured with minimum losses and wastage.

Prognosis of Hepatocellular Carcinoma Patients Who Achieved Long-Term Recurrence-Free Survival After Curative Therapy: Impact of the ALBI Grade

Background/AimsSome patients experience very late recurrence of HCC more than 5 years after initial therapy. We aimed to clarify the predictive factors for very late recurrence of HCC in such cases. MethodsAmong 807 HCC patients undergoing surgical resection or ablative therapy with curative intent, the patients who survived for 5 years without any recurrence were reviewed. The prognosis and possible predictive factors for late recurrence were analyzed retrospectively. ResultsA total of 184 patients survived for more than 5 years without recurrence. Among them, 61 patients experienced recurrence, at a median of 6 years after initial therapy. In univariate analysis, the pre-treatment aspartate aminotransferase, alanine aminotransferase, Child-Pugh class, and ALBI grade were not related to recurrence, but those at 5 years after treatment were significantly related to recurrence. By multivariate analysis, an ALBI grade of 2–3 at 5 years was an independent risk factor for recurrence (P<0.0001). Moreover, variation of the ALBI grade over the 5 years after the initial treatment was significantly related to recurrence-free survival. ConclusionsThe ALBI grade is an effective index of the variation in liver function after curative therapy and may be a useful prognostic factor for the long-term recurrence-free survival of HCC patients.

Differences In Wearable Running Power On Three Different Surfaces During Submaximal Running

Running pace is one of the primary measures of running intensity, however, variations in grade and surface limit quantifying intensity solely based on pace. With the advent of wearable running power meters, runners can assess the external work stimulus inclusive of pace, grade, and surface. PURPOSE: To assess differences in running power (RP) on different surfaces, a Stryd running power meter was evaluated based on submaximal running on three different surfaces. METHODS: Eight collegiate cross country runners (male n=4, age=21.25±0.50 yrs, weight=63.45±9.73 kg, height=178.5±10.82 cm; female n=4, age=20±1.41 yrs, weight=56.45±4.95 kg, height=169.5±7.97 cm) participated in two trials of submaximal running at 85% of lactate threshold (LT) on each of three different surfaces: treadmill, grass, and track. All subjects completed a a VO2max and LT running test. For this investigation, sub-maximal running speed/pace was determined from the maximal effort / LT test. During subsequent submaximal running trials, ventilatory and metabolic measures and heart rate (HR) were collected with a portable breath by breath analyzer (COSMED K4B2) and HR monitor (Polar). For the track and grass submaximal running, the runners were paced by a cyclist maintaining a constant speed using a speedometer. ANOVAs were run between trials on all surfaces including treadmill, track and grass. RESULTS: The running power for the treadmill surface was significantly lower than both the grass and track (Mean±SE: RPtreadmill = 237±12.7 W*, RPgrass = 244±13.4 W, RPtrack = 242±13.0 W). There were no significant differences between grass and track surfaces (*p<0.05). CONCLUSIONS: This investigation found that running power (Stryd) is less when running on a treadmill compared to running on grass and a track which may indicate a different training stimulus when training on a treadmill versus other surfaces.

Pilot Point Optimization of Mining Boundaries for Lateritic Metal Deposits: Finding the Trade-off Between Dilution and Ore Loss

Geological contacts in lateritic metal deposits (footwall topographies) often delineate the orebody boundaries. Spatial variations seen in such contacts are frequently higher than those for the metal grades of the deposit. Therefore, borehole spacing chosen based on the grade variations cannot adequately capture the geological contact variability. Consequently, models created using such boreholes cause high volumetric uncertainties in the actual and targeted ore extraction volumes, which, in turn, lead to high unplanned dilution and ore losses. In this paper, a method to design optimum ore/mining boundaries for lateritic metal deposits is presented. The proposed approach minimizes the dilution/ore losses and comprises two main steps. First, the uncertainty on the orebody boundary is represented using a set of stochastic realizations generated with a multiple-point statistics algorithm. Then, the optimal orebody boundary is determined using an optimization technique inspired by a model calibration method called Pilot Points. The pilot points represent synthetic elevation values, and they are used to construct smooth mining boundaries using the multilevel B-spline technique. The performance of a generated surface is evaluated using the expected sum of losses in each of the stochastic realizations. The simulated annealing algorithm is used to iteratively determine the pilot point values which minimize the expected losses. The results show a significant reduction in the dilution volume as compared to those obtained from the actual mining operation.

O efeito da padronização das notas sobre os resultados da avaliação dos cursos de Engenharia Civil

This study aims to present an analysis of the effect of grade standardization on the results of the assessment of Civil Engineering undergraduate courses. The analyzed data came from the assessment carried out in the year 2014. Initially, it was performed a theoretical analysis of the equations that define the standardization procedure to assess the effect on mean, standard deviation and coefficient of variation of original grades. Following, it is presented a comparison between the statistics of original grades and standard grades to show the effect of different scale amplitudes of the evaluation components. It was also calculated the correlation among the variables used to define the course preliminary concept (CPC). The results showed low correlation between the variables Note and IDD and the other variables that are part of the CPC. Finally, we presented two alternatives to define scale ranges to the evaluation components, and compared the CPC values calculated from those two alternatives to the CPC values calculated from the current standardization procedure. The results showed that the current standardization procedure increased the relative frequency of both 2 and 3 concepts, and decreases the relative frequency of 4 concept compared to the two alternatives suggested.

Fast screening of the fatigue properties of thermoplastics reinforced with short carbon fibers based on thermal measurements

The goal of this paper is to investigate the ability of the heat build-up technique to predict the fatigue lifetime of injected thermoplastic reinforced with short carbon fibers. Several commercial grades and filler ratios are considered in order to challenge the ability of the technique to capture the influence of these variations. First, the materials are investigated and the mechanical and thermal protocols are described. The way to build the heat-build-up curves is outlined. Then, the results obtained from the heat build-up and fatigue experiments are presented. The heat build-up curves are obtained both from measurements performed on the front surface of the sample and from the side surface. Finally, these results are used to discuss two main points. The first is the validity of the hypotheses needed to apply the approach, ranging from the evaluation of the dissipation to the fatigue response. The second is the capability to predict the fatigue curves accurately through an energetic criterion, and to identify the influence of the variations of matrix grade and fiber content on the fatigue properties. It appears that the predictions obtained match the results obtained from classic fatigue tests and validates the use of the technique for fast material screening.

Grader Variability and the Importance of Reference Standards for Evaluating Machine Learning Models for Diabetic Retinopathy

Use adjudication to quantify errors in diabetic retinopathy (DR) grading based on individual graders and majority decision, and to train an improved automated algorithm for DR grading. Retrospective analysis. Retinal fundus images from DR screening programs. Images were each graded by the algorithm, U.S. board-certified ophthalmologists, and retinal specialists. The adjudicated consensus of the retinal specialists served as the reference standard. For agreement between different graders as well as between the graders and the algorithm, we measured the (quadratic-weighted) kappa score. To compare the performance of different forms of manual grading and the algorithm for various DR severity cutoffs (e.g., mild or worse DR, moderate or worse DR), we measured area under the curve (AUC), sensitivity, and specificity. Of the 193 discrepancies between adjudication by retinal specialists and majority decision of ophthalmologists, the most common were missing microaneurysm (MAs) (36%), artifacts (20%), and misclassified hemorrhages (16%). Relative to the reference standard, the kappa for individual retinal specialists, ophthalmologists, and algorithm ranged from 0.82 to 0.91, 0.80 to 0.84, and 0.84, respectively. For moderate or worse DR, the majority decision of ophthalmologists had a sensitivity of 0.838 and specificity of 0.981. The algorithm had a sensitivity of 0.971, specificity of 0.923, and AUC of 0.986. For mild or worse DR, the algorithm had a sensitivity of 0.970, specificity of 0.917, and AUC of 0.986. By using a small number of adjudicated consensus grades as a tuning dataset and higher-resolution images as input, the algorithm improved in AUC from 0.934 to 0.986 for moderate or worse DR. Adjudication reduces the errors in DR grading. A small set of adjudicated DR grades allows substantial improvements in algorithm performance. The resulting algorithm's performance was on par with that of individual U.S. Board-Certified ophthalmologists and retinal specialists.

Peer Evaluation: Enhancing learning Opportunities and Reducing Marking Effort

Abstract Evaluation of report-based assignments, especially in larger classes, adds a considerable marking load. Even with detailed rubrics, subjectivity may lead to grading variations and inaccuracies. Evaluation of others’ work can also be a very informative and educational experience, improving their skill through exposure to a broader performance range. Involving students in peer evaluation can potentially address both of these issues by reducing marking load, providing alternate (and increased number of) assessments, and by exposing students to a broader spectrum of report skills thus enhancing their own knowledge.&#x0D; This paper discusses the results of an experiment in peer assessment and whether it can be exploited to reduce marking effort, improve accuracy for report assignment evaluation and improve student skill. The data was gathered from assignments in two different engineering classes: a second year course on safety and environmental stewardship, and a senior course on engineering economics.&#x0D; For the second-year course, an individual essay assignment was marked by the instructor and two peers. The three evaluations were analyzed to assess the accuracy and assign a grade. For the senior course, a group report on a case study was self and peer evaluated. These evaluations were used to derive a grade for the report directly if the self and peer results were within a prescribed tolerance; other cases were resolved by instructor intervention. The results were analyzed considering the number of outliers, range of scores, and the number of cases which had to be resolved by theinstructor.&#x0D; Parameters considered in assessing the results of the experiment included: the correlation between assessments, the learning opportunities for students, and instructor marking effort required. (preliminary analysis) Results suggest positive gains in reducing effort. Improved accuracy and enhanced student learning are also expected.&#x0D;

Using electrogeochemical approach to explore buried gold deposits in an alpine meadow-covered area

Exploration for buried gold ores and other deeply buried ores, especially in high altitude localities, is one of the tough challenges facing the geological world today. Fast and efficient ore prospecting methods are badly needed to deal with the situation. This paper documents a test that, for the first time, uses an electrogeochemical approach to prospect ores in the alpine meadow-covered Bangzhuoma area and its periphery in Qinghai–Tibet Plateau. The results were compared with conventional soil measurements from a 2D prospection, and an ideal model of electrogeochemical anomaly formation in the area was established based on the comparison in order to provide theoretical guidance to buried ore prospecting in areas with similar conditions. The research shows that: (1) For exploration of deeply-buried mineral deposits, an electrogeochemical approach is better than soil measurements in terms of correspondence between element content values and anomaly forms and spatial distribution of known deposits in sections. Anomalies of high to low temperature element associations (Bi–Mo; Au–Ag–As–Bi and Au–Ag) and clear zonation were also observed along vertical vein runs in the sections. Based on integration of the observation with geological characteristics of the sections, we propose to use Au, Ag and As as the electrogeochemical indicators and Bi and Mo as the electrogeochemical tracing elements to guide further analysis. (2) Judging from element statistics and the scale, intensity, and range of anomalies in plan maps, we found that an electrogeochemical approach is less affected by topography and secondary actions. The plan maps also show that elemental differentiation coefficients of the study area are in an ascending order of Ag (0.67) < Mo (0.85) < Bi (0.97) < Au (1.51) < As (2.35), better representing the element distribution in the area and yielding more striking and concentrated anomalies for known deposits than that of the soil measurements. Apart from that, electrogeochemical anomalies were observed in the south of lines 002 and 003 and the central of lines 008 and 009. We suggest the existence of deeply-buried mineral deposits based on analyses of element combinations and gold grade variations in samples taken from exploratory trenches in the area. (3) A three-stage (referring to the ore body dissolution, the mineralogenetic particle migration, and the mineralogenetic particle unloading) electrogeochemical ideal model was established for the study area, which takes into account moderate rainfall, high altitude, low air pressure, well-developed vegetation and roots, and an Upper Triassic Nieru Formation carbonaceous sandy slate as overburden.

Differences in breast cancer incidence among young women aged 20-49years by stage and tumor characteristics, age, race, and ethnicity, 2004-2013.

Younger women diagnosed with breast cancer have poorer prognoses and higher mortality compared to older women. Young black women have higher incidence rates of breast cancer and more aggressive subtypes than women of other races/ethnicities. In this study, we examined recent trends and variations in breast cancer incidence among young women in the United States. Using 2004-2013 National Program of Cancer Registries and Surveillance, Epidemiology, and End Results Program data, we calculated breast cancer incidence rates and trends and examined variations in stage, grade, and tumor subtype by age and race/ethnicity among young women aged 20-49years. The majority of breast cancer cases occurred in women aged 40-44 and 45-49years (77.3%). Among women aged<45years, breast cancer incidence was highest among black women. Incidence trends increased from 2004 to 2013 for Asian or Pacific Islander (API) women and white women aged 20-34years. Black, American Indian or Alaska Native, and Hispanic women had higher proportions of cases diagnosed at later stages than white and API women. Black women had a higher proportion of grade III-IV tumors than other racial/ethnic groups. Across all age groups, incidence rates for triple-negative breast cancer were significantly higher in black women than women of other races/ethnicities, and this disparity increased with age. Breast cancer among young women is a highly heterogeneous disease. Differences in tumor characteristics by age and race/ethnicity suggest opportunities for further research into personal and cultural factors that may influence breast cancer risk among younger women.

The clinical implications of adopting new criteria for the grading of internal carotid artery stenosis.

A patient's eligibility for carotid endarterectomy (CEA) is determined primarily by the degree of carotid stenosis detected on duplex ultrasound. The Australasian Society for Ultrasound in Medicine (ASUM) criteria are widely used to grade carotid stenoses in many practices throughout Australasia. We sought to investigate the potential impact on the grading of carotid artery stenosis if practitioners switched from the ASUM criteria to the United Kingdom's joint recommendation (UKJR) criteria by reviewing 100 patients with a haemodynamically significant carotid artery stenosis. We found agreement between the criteria in 100% of cases for stenoses <50%, in 80% of cases for stenoses 50-69%, in 89% of cases for stenoses ≥70% and in 100% of cases for stenoses ≥80%. While there was variation in grading of stenoses in 16% of cases, reclassification resulted in no change in the number of patients eligible for CEA. The UKJR guideline enabled more precise categorisation of haemodynamically significant stenosis into deciles. Because the UKJR guideline is more comprehensive, we believe that adopting this guideline would enable the ultrasound practitioner to grade carotid stenoses more precisely, better understand the nuances of carotid duplex imaging and more successfully navigate and interpret complex carotid examinations, without impacting the number of patients eligible for CEA.

Overall buckling behaviour and design of high-strength steel welded section columns

Practical use of high-strength (HS) steel in contemporary construction has become one of the most important design solutions. Loading capacities of columns may benefit enormously from the HS steel, whilst their overall buckling behaves differently compared with conventional mild (CM) steel columns due to varying effects of initial imperfections and inelastic properties of the HS steel materials. Despite a number of investigations regarding the HS steel columns being undertaken, there is lack of research focused on variation of HS steel grades and their effects. To deepen understanding of overall buckling behaviour of the HS steel columns, a comprehensive review of an extensive body of column test data available in the literature is carried out in the present paper, based on which a three-dimensional finite element (FE) model developed herein is validated. Parametric analyses are subsequently undertaken with various HS steel grades, welded cross-sectional geometric parameters, slenderness values and initial imperfections being involved. The FE analysis results are also compared with calculation values in accordance with national standards. It has been demonstrated that with an increase of the grade of HS steel, effects of imperfections decrease whilst that of Y/T ratios are rather limited; reduction effects on the overall buckling strength become less severe, and therefore higher column curves available in current national standards may be selected and imperfection factors in the alternative column curve equations proposed herein descend accordingly. In addition, new theoretical column curves based on Perry-Robertson formula are developed by introducing imperfection parameters independent on the steel strength.

Feulgen stain as a special stain for mitotic figures and apoptotic bodies in oral squamous cell carcinoma

Background: Oral cancer is one of the most prevalent cancers worldwide. The oral squamous cell carcinoma (OSCC) is graded for the proper treatment planning, and it has been a subjective phenomenon. This grading depends on several features, of which the presence of mitotic figures and apoptotic bodies is one of the important criteria. The routine hematoxylin and eosin (H and E) staining may help in identifying the mitotic figures and apoptotic bodies, but it is difficult to identify accurately. Thus, an attempt was made to evaluate the efficacy of crystal violet and Feulgen stain in identifying the mitotic figures and apoptotic bodies and to observe any variation in different grades of carcinoma. Aims: This study was aimed at using crystal violet and Feulgen stain in identifying mitotic figures and apoptotic bodies in different grades of OSCC. Materials and Methods: Fifteen diagnosed cases of OSCC were retrieved and stained with routine H and E, crystal violet stain, and Feulgen stain. All the sections were scanned for mitotic figures and apoptotic bodies. Apoptotic index (AI) and mitotic index (MI) were calculated. AI and MI were expressed as the average of a total number of apoptotic and mitotic cells counted in ten high-power fields. Results: A significant increase in MI and AI was found in Feulgen stain than crystal violet and H and E stain. Conclusion: Feulgen stain can be considered as the best, cost-effective, relatively cheap stain to visualize mitotic figures and apoptotic bodies.

Effect of binder grade on performance parameters of asphaltic concrete paving mixtures

This study explores effect of binder grade variation on the performance parameters of stiffness, fatigue, and permanent deformation using different asphaltic concrete paving mixtures. Two penetration grade binders (40/50 and 80/100), four gradations (two wearing and two base courses) and single limestone aggregate source were used. Superpave Gyratory Compactor (SGC) was employed to fabricate specimens for Dynamic Modulus |E∗| test, Repeated Load Deformation Test (Flow Number Test, FN) and Static Creep Test (Flow Time test, FT) using Asphalt Mixture Performance Tester (AMPT). The |E∗| test was carried out for a range of temperatures (4.4–54.4 °C) and a frequency sweep (25–0.1 Hz), while FN and FT tests were performed at a single effective temperature of 54.4 °C and 300 kPa stress level. The |E∗| test results were subjected to the non-linear optimization technique to develop the stress-dependent master curves which reveal that the grade of bitumen significantly influences the stiffness of mixtures. The combination of the |E∗| and the phase angle pronounced into fatigue parameter which describes the fatigue behavior of a mix, and results indicate that the softer grade translates into higher fatigue resistance and vice versa. We observe that the 40/50 binder, ​on average, is 1.8 times more rut-resistant than the 80/100 binder. Further, this study also develops a non-linear regression model to express |E∗| as a function of testing temperature, loading frequency, and mixture volumetric parameter.

Investigation of Grade Bias Due to Core Loss Using Bivariate Conditional Distribution

Three-dimensional modeling of a mineral deposit was conducted based on the samples collected from the surficial and deep parts of the deposit. One of the factors that affect the quality of data is the recovery of cores acquired during exploration drilling. As the core recovery reduces, the grade in core or drilling mud increases. Core loss can introduce unpredictable errors and negative or positive bias into the mineral resources estimation. Investigating the grade–recovery relationship in a bivariate space helps to detect the grade bias. In an ideal state, there is no correlation between grade and recovery. In case the grade–recovery relationship possesses a negative or positive correlation, the grade bias is likely to be due to core loss. In practice, however, because there are many data in boreholes sample database, the grade–recovery relationship is not properly determined on a simple scatter plot of grade versus core recovery. Application of conditional distributions in a bivariate space provides the necessary tool for investigating the simultaneous variations of grade and core recovery. Therefore, having converted the grade and core recovery data into the normal space, the conditional grade distribution was determined for various recoveries, and then, the conditional grades expectations were determined and plotted against the recovery to investigate the grade–recovery relationship. Application of the proposed method in three different deposits showed that in low recoveries, due to waste loss, the grade values were overestimated, whereas in high recoveries, due to ore loss, they were underestimated.

Performance in grade 12 mathematics and science predicts student nurses' performance in first year science modules at a university in the Western Cape.

BackgroundThe demand for highly qualified and skilled nurses is increasing in South Africa as well as around the world. Having a background in science can create a significant advantage for students wishing to enrol for an undergraduate nursing qualification because nursing as profession is grounded in scientific evidence.AimThe aim of this study was to investigate the predictive validity of grade 12 mathematics and science on the academic performance of first year student nurses in science modules.MethodA quantitative research method using a cross-sectional predictive design was employed in this study. The participants included first year Bachelor of Nursing students enrolled at a university in the Western Cape, South Africa. Descriptive and inferential statistics were performed to analyse the data by using the IBM Statistical Package for Social Sciences versions 24. Descriptive analysis of all variables was performed as well as the Spearman’s rank correlation test to describe the relationship among the study variables. Standard multiple linear regressions analysis was performed to determine the predictive validity of grade 12 mathematics and science on the academic performance of first year student nurses in science modules.ResultsThe results of this study showed that grade 12 physical science is not a significant predictor (p > 0.062) of performance in first year science modules. The multiple linear regression revealed that grade 12 mathematics and life science grades explained 37.1% to 38.1% (R2 = 0.381 and adj R2 = 0.371) of the variation in the first year science grade distributions.ConclusionBased on the results of the study it is evident that performance in grade 12 mathematics (β = 2.997) and life science (β = 3.175) subjects is a significant predictor (p < 0.001) of the performance in first year science modules for student nurses at the university identified for this study.

Primary salivary gland malignancies: a review of clinicopathological evolution, molecular mechanisms and management.

Salivary gland cancers are a complex group of tumours with variations in location, type and grade, all of which influence their biological behaviour. The understanding of salivary gland pathology has evolved at the molecular level in the last decade leading to identification of distinct entities, development of improved methods of diagnosis as well as identifying therapeutic targets for selected high-grade tumours. This article focuses on these advances and their impact on the management of primary salivary gland cancers.