Minimum Percentile Research Articles

The influence of teacher sociodemographic factors and school characteristics on the identification of gifted students

ABSTRACT This study examines some teacher sociodemographic factors and school characteristics that may influence teachers’ identification of gifted students. Teachers initially nominated a sample of 505 students aged 7–17 years (M = 11.51, SD = 2.07), but only 359 completed a general intelligence test and 225 reached the minimum percentile to be considered potentially gifted. Only 20 of these had a previous diagnosis of giftedness. Results show that the teachers’ identification had a sensitivity of 63% and that the teacher’s sex and the type of school significantly influenced the identification of giftedness. Female teachers and teachers in private schools made more accurate identifications. There was no evidence for the influence of school setting or the educational stage.

Post-acquisition standardization of positron emission tomography images.

Tissue radiotracer activity measured from positron emission tomography (PET) images is an important biomarker that is clinically utilized for diagnosis, staging, prognostication, and treatment response assessment in patients with cancer and other clinical disorders. Using PET image values to define a normal range of metabolic activity for quantification purposes is challenging due to variations in patient-related factors and technical factors. Although the formulation of standardized uptake value (SUV) has compensated for some of these variabilities, significant non-standardness still persists. We propose an image processing method to substantially mitigate these variabilities. The standardization method is similar for activity concentration (AC) PET and SUV PET images with some differences and consists of two steps. The calibration step is performed only once for each of AC PET or SUV PET, employs a set of images of normal subjects, and requires a reference object, while the transformation step is executed for each patient image to be standardized. In the calibration step, a standardized scale is determined along with 3 key image intensity landmarks defined on it including the minimum percentile intensity , median intensity , and high percentile intensity and are estimated based on image intensities within the body region in the normal calibration image set. The optimal value of the maximum percentile corresponding to the intensity is estimated via an optimization process by using the reference object to optimally separate the highly variable high uptake values from the normal uptake intensities. In the transformation step, the first two landmarks-the minimum percentile intensity , and the median intensity -are found for the given image for the body region, and the high percentile intensity is determined corresponding to the optimally estimated high percentile value . Subsequently, intensities of are mapped to the standard scale piecewise linearly for different segments. We employ three strategies for evaluation and comparison with other standardization methods: (i) comparing coefficient of variation of mean intensity within test objects across different normal test subjects before and after standardization; (ii) comparing mean absolute difference ( ) of mean intensity within test objects across different subjects in repeat scans before and after standardization; (iii) comparing of mean intensity across different normal subjects before and after standardization where the scans came from different brands of scanners. Our data set consisted of 84 FDG-PET/CT scans of the body torso including 38 normal subjects and two repeat-scans of 23 patients. We utilized one of two objects-liver and spleen-as a reference object and the other for testing. The proposed standardization method reduced and by a factor of 3-8 in comparison to other standardization methods and no standardization. Upon standardization by our method, the image intensities (both for AC and SUV) from two different brands of scanners become statistically indistinguishable, while without standardization, they differ significantly and by a factor of 3-9. The proposed method is automatic, outperforms current standardization methods, and effectively overcomes the residual variation left over in SUV and inter-scanner variations.

Spatiotemporal Changes in Frost Indicators in Southeastern Spain (1950–2020): Influence of the East Atlantic Index (EA)

Abstract The southeastern interior of the Iberian Peninsula (Spain) is characterized by a complex orography, which determines a pronounced altitudinal gradient, significant slopes, and marked valleys with important temperature inversion processes. In this work, to analyze the yearly and seasonal evolution of minimum temperatures, six indicators related to minimum temperatures were used: the frost days (FD) and number of days with minimum temperature below −2°C (TNltm2), 10th temperature minimum percentile (TN10p), absolute minimum temperatures (TNn), average minimum temperatures (TNm), and cold-spell duration index (CSDI). For this, the Spearman nonparametric statistical test was used to analyze data from a total of 22 meteorological stations (1950–2020), using a daily resolution of minimum temperatures. Significant changes during the study period were revealed, especially between the 1960s and 1990s. In most cases, there has been a statistically significant increase in the minimum temperatures in the study area, except in the western (most mountainous) part, where the dynamics differed from the rest of the interior of the southeast of the peninsula. Nine large global teleconnection patterns were analyzed in relation to the average minimum temperatures in the study area. These are well-characterized indices for the Northern Hemisphere, which show a very high correlation of the average minimum temperatures with the temporal evolution of the global climate pattern of the east Atlantic (EA) index, especially in the Mediterranean region of the Iberian Peninsula, where it seems to have a very marked influence. Significance Statement We analyzed variation in observed minimum temperatures during 1950–2020 in inland southeastern Spain. Temporal analysis of “east Atlantic index” cycles and their interrelation with frost days and minimum temperatures is very relevant for seasonal meteorological prediction in the study area, where agroindustry represents 20% of GDP. The results show a significant decrease in frost days and an increase in average minimum temperature, especially in coastal and prelittoral areas. The variations are less important mountainous western areas, where frost days have even increased. This is explained by a change in the atmospheric dynamics in midlatitudes of the Atlantic Ocean, quantified by the east Atlantic global teleconnection index, which has a high statistical correlation with Spanish minimum temperatures, especially in winter.

Robust stimulated Raman exact passage using shaped pulses

We developed single-shot shaped pulses for ultra high fidelity (UH-fidelity) population transfer on a 3-level quantum system in lambda configuration. To ensure high fidelity, we use the Lewis-Riesenfeld (L-R) method to derive a family of solutions leading to an exact transfer, where the solutions follow a single dynamical mode of the L-R invariant. Among this family, we identify a tracking solution with a single parameter to control simultaneously the fidelity of the transfer, the population of the excited state, and robustness. We define a measure of the robustness of an UH-fidelity transfer as the minimum percentile deviation on the pulse areas at which the infidelity rises above $10^{-4}$. The robustness of our shaped pulses is found superior to that of Gaussian and adiabatically-optimized pulses for moderate pulse areas.

Densidade colimétrica das áreas de extrativismo de ostras em relação aos fatores ambientais em Cananeia (SP)

A água nas áreas de extrativismo de ostras do Estuário de Cananeia foi avaliada por meio da análise colimétrica durante o período de 2005 a 2011. Averiguou-se que a média geométrica dos coliformes termotolerantes (18,80 NMP.100mL-1) está dentro dos limites permitidos pelo CONAMA 357/2005, mas o percentil não alcançou o mínimo estabelecido pela Resolução (80%). Verificou-se que houve correlação positiva entre coliformes com o fator pluviosidade e correlação negativa com a salinidade. Constatou-se também que a preamar de sizígia apresentou menor densidade de coliformes e diferiu significativamente dos outros estofos analisados. Concluiu-se que a concentração de coliformes nos locais analisados demonstrou variabilidade temporal e que sofre influência direta de salinidade, pluviosidade e amplitude de maré.

Assigning publications to multiple subject categories for bibliometric analysis

Purpose – This study is concerned with a problem in measuring citation impact with the aid of percentile data, which arises from the assignment of publications (or the journals in which the publications have appeared) by Thomson Reuters for the Web of Science to more than one subject category. If there is more than one subject category for a publication, it is initially unclear which category is to be used to create the reference set for the calculation of the percentile. This paper seeks to address these issues. Design/methodology/approach – In this study the author would like to look at whether the calculation of differences between the citation impact of research institutions is affected by whether the minimum (the maximum percentile), the maximum (the minimum percentile), the mean or the median impact (percentile) for the different subject categories is used. The study is based on a sample of percentile data for three research institutions (n=4,232). Findings – The result of the comparison of citation impact of the three institutions remains very similar for all the calculation methods, but on a different level. Originality/value – It is the first study, which investigates how far it makes a difference in the comparison of the citation impact of three different research institutes whether – with multiple assignments of subject categories to one publication – the minimum, the maximum, the mean or the median inverted percentile is used. An answer to the question is very relevant since different methods are used in practical application. For example, the web-based research evaluation tool InCites uses the minimum percentile.

How Important Are American Board of Surgery In-Training Examination Scores When Applying for Fellowships?

The American Board of Surgery In-Training examination (ABSITE) first was administered in 1975 to evaluate a resident's general knowledge as well as the deficiencies within the resident and surgical program. The added importance of this examination in recent years stems from a correlation between ABSITE performance and performance on the American Board of Surgery qualifying examination. However, data are lacking in regard to how fellowship programs view ABSITE scores when considering applicants. Thus, this study was initiated to determine the importance of the ABSITE for surgical residents applying to fellowships. Program coordinators and directors of various surgical fellowships were sent a short survey in regard to the ABSITE. The data then were analyzed. One hundred forty-eight surveys were completed, with 74.8% of the programs ranking the importance of ABSITE scores as 3 or 4 (on a scale of 1 through 5). Most programs (78.9%) reported no minimum percentile requirement. Those that did required a mean percentile of 54.4. Of the programs, 57.8% placed a greater emphasis on the senior examination versus the junior examination (p = 0.06). When compared with other application factors, the ABSITE score ranked 3rd behind letters of recommendation and a candidate's residency program. Colon and rectal surgery placed the highest importance on ABSITE scores, whereas transplant surgery placed the lowest importance. The ABSITE score is an important factor for residents applying to surgical fellowship; however, more weight is given to candidates' letters of recommendation and his or her residency program. Applicants should aim to score above the 50th percentile to be competitive for most fellowship programs.

Time-delayed rupture of stones under low tensile and bending stress states

The advancements of research dealing with the time-delayed behaviour of building stones are presented. In preceding papers, the results of long-term tensile and bending tests conducted on one type of Carrara marble, two sandstones, and one limestone were reported. A composite phenomenological model was also defined which permitted to suitably reproduce the recorded responses. In this paper, the tests carried out by applying the minimum percentile rate of the fracture loads (equal to 35%), having in the meantime arrived at completion, are described. The outcomes of these tests confirm the basic features of the creep response observed in the previous sections of the experimental programme. By updating the experimental time-to-rupture curves with reference to the new data, an asymptotic trend towards the elastic limit values of the materials is noted. A modified version of the time-to-rupture law associated with the tertiary branch of the phenomenological model is supplied, which allows to further improve the relevant prediction potentialities.

The Relative Sizes of Percentiles

In anthropometric design, one usually tries to accommodate the widest range of sizes from small to large. The accelerating ratio of physical size to percentile as one approaches the upper extreme end of the Gaussian distribution, with its generally concomitant cost and/or spatial impacts on the physical system, can often limit the maximum percentile or minimum percentile which can be realistically accommodated. However, what is not generally realized is the relative sizes of the physical dimensions involved because so much work is done with percentiles which are dimensionless quantities. This paper presents several figures which provide some idea of the relative physical sizes of percentiles. The rather small coefficient of variance for anthropometric measurements means that the difference between say the 50th and the 95th percentiles while being a difference of “45 percentile points” is only a matter of a few percent in physical size. Such considerations can help in providing a better understanding of the tradeoff in percentiles and percent and perhaps adds some physical interpretations of percentiles.