2,115 research outputs found

    The Associations between the Scores on the ACT Test and Tennessee\u27s Value-Added Assessment in 281 Tennessee High Schools.

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    The purpose of this study was to explore the relationships between and among various demographic and test score data with American College Testing (ACT) scores in 281 Tennessee high schools. This study also addressed which high school characteristics were related to the number of students meeting the ACT requirement for Tennessee lottery scholarships. In addition, this study examined Tennessee Value Added Assessment System\u27s (TVAAS) assessment of ACT scores and its distribution of grades to Tennessee\u27s high schools based upon its Value-Added analysis. The researcher performed correlations and multivariable linear regressions using socioeconomic status, ethnicity, dropout rate, graduation rate, attendance, average daily membership, per-pupil expenditure, teacher salary, Gateway exams, English I scores, and math foundations scores as independent variables and ACT scores as the dependent variable. The strengths of the correlations were examined and the best combination of independent variables was used to predict future ACT scores. Schools were divided into quartiles, based upon average daily membership and attendance rates, in order to analyze the differences in r2 values among the quartiles when running regressions to predict ACT scores. Quartiles, based upon the percentage of students qualifying for free/reduced meals, ethnicity, and average daily membership were used to study the difference in TVAAS\u27 grade distribution based upon its assessment of ACT scores. The findings indicated that English I and II scores are most strongly associated with ACT composite scores including the four ACT subtests: math, English, reading, and science. English scores were found to be more strongly associated with ACT math scores than Algebra I scores and more strongly associated with ACT science scores than biology scores. It was found that the 21 composite ACT score requirements of Tennessee\u27s lottery scholarships predominantly favored Caucasian students who did not qualify for free/reduced-priced meals. It was also discovered that TVAAS\u27 ACT grades were unevenly distributed when schools were divided into quartiles based upon the percentage of students qualifying for free/reduced-priced meals, ethnicity, and average daily membership. Only one school in the quartile containing the schools with the highest percentage of students qualifying for free/reduced-priced meals scored above the state\u27s average gain in the reading section of the ACT test

    Natural variation in female reproductive hormones does not affect contrast sensitivity.

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    Evidence suggests that females experience adaptive shifts in facial preferences across the menstrual cycle. However, recent discussions and meta-analyses suggest that these findings are equivocal. A previously unexplored question is the extent to which shifts in female preferences are modulated by hormone-dependent changes occurring in low-level vision, such as visual sensitivity. This mechanistic approach has been a novel method for investigating the extent to which complex perceptual phenomena are driven by low-level versus higher-level perceptual processes. We investigated whether the contrast sensitivity function-an early dimension of vision-is also influenced by variation in female reproductive hormones. Visual contrast thresholds were measured for 1, 4 and 16 cycles/degree gratings during the ovulatory, luteal and menstrual phases of the menstrual cycle in naturally cycling women, and women using oral contraceptives. Male participants were tested at similar time intervals. Results showed that visual contrast sensitivity does not differ according to sex, or use of oral contraception, nor does it vary relative to hormonal shifts across the menstrual cycle. These findings suggest that shifts in female preferences are not driven by changes in visual sensitivity, and are therefore likely attributable to changes in higher-level perception or cognition

    Contrast normalisation masks natural expression-related differences and artificially enhances the perceived salience of fear expressions

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    Fearful facial expressions tend to be more salient than other expressions. This threat bias is to some extent driven by simple low-level image properties, rather than the high-level emotion interpretation of stimuli. It might be expected therefore that different expressions will, on average, have different physical contrasts. However, studies tend to normalise stimuli for RMS contrast, potentially removing a naturally-occurring difference in salience. We assessed whether images of faces differ in both physical and apparent contrast across expressions. We measured physical RMS contrast and the Fourier amplitude spectra of 5 emotional expressions prior to contrast normalisation. We also measured expression-related differences in perceived contrast. Fear expressions have a steeper Fourier amplitude slope compared to neutral and angry expressions, and consistently significantly lower contrast compared to other faces. This effect is more pronounced at higher spatial frequencies. With the exception of stimuli containing only low spatial frequencies, fear expressions appeared higher in contrast than a physically matched reference. These findings suggest that contrast normalisation artificially boosts the perceived salience of fear expressions; an effect that may account for perceptual biases observed for spatially filtered fear expressions

    An inelastic neutron scattering investigation of the temporal behaviour of the hydrocarbonaceous overlayer of a prototype Fischer-Tropsch to olefins catalyst

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    Sasol Ltd., the University of Glasgow and the EPSRC [award reference EP/P505534/1] are thanked for the provision of a postgraduate studentship (ALD). The Royal Society is thanked for the provision of an Industry Fellowship (PBW).A dual sodium and sulfur promoted haematite, representative of a candidate Fischer-Tropsch to olefins (FTO) catalyst, is prepared and contrasted with the performance of an unpromoted hematite sample in the ambient pressure CO hydrogenation reaction at 623 K as a function of time-on-stream (0–24 h). In-situ post-reaction temperature-programmed oxidation measurements show the carbon evolutionary phase of the catalyst conditioning process to be retarded for the FTO catalyst. Ex-situ inelastic neutron scattering measurements show the promoters perturb the formation of a previously described hydrocarbonaceous overlayer. Specifically, whilst the sp3 hybridised C–H modes of the hydrocarbonaceous overlayer are almost unaffected by the additives, the formation of the overlayer’s sp2 hybridised C–H modes are noticeably impeded. The results are discussed in terms of the Na/S promoters disturbing the formation of an ordered hydrocarbonaceous overlayer that is thought to constrain the supply of adsorbed hydrogen atoms, which favours the formation of unsaturated hydrocarbons associated with the FTO process.Publisher PDFPeer reviewe

    Helping behaviour during cooperative learning and learning gains

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    Is helping behaviour (i.e., solicited help and peer tutoring) during cooperative learning (CL) related to subsequent learning gains? And can teachers influence pupils’ helping behaviour? One hundred one 5th grade pupils from multiethnic schools, 10-12 years old, participated in the study. Forty two pupils (31 immigrant) worked in an experimental condition, characterized by the stimulation of solicited high quality help and 59 (24 immigrant) worked in a control condition. It was found that learning gains were predicted positively by pupils’ unsolicited helping behaviour (i.e., peer tutoring) and negatively by solicited help. Furthermore, teachers were able to affect pupils’ low quality solicited help only. Lastly, immigrant pupils used less helping behaviour than local pupils, irrespective of CL setting

    Respiration and Heart Rate at the Surface between Dives in Northern Elephant Seals

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    All underwater activities of diving mammals are constrained by the need for surface gas exchange. Our aim was to measure respiratory rate (fb) and heart rate (fh) at the surface between dives in free-ranging northern elephant seals Mirounga angustirostris. We recorded fb and fh acoustically in six translocated juveniles, 1.8-2. 4 years old, and three migrating adult males from the rookery at Ano Nuevo, California, USA. To each seal, we attached a diving instrument to record the diving pattern, a satellite tag to track movements and location, a digital audio tape recorder or acoustic datalogger with an external hydrophone to record the sounds of respiration and fh at the surface, and a VHF transmitter to facilitate recovery. During surface intervals averaging 2.2+/−0.4 min, adult males breathed a mean of 32.7+/−5.4 times at a rate of 15. 3+/−1.8 breaths min(−)(1) (means +/− s.d., N=57). Mean fh at the surface was 84+/−3 beats min(−)(1). The fb of juveniles was 26 % faster than that of adult males, averaging 19.2+/−2.2 breaths min(−)(1) for a mean total of 41.2+/−5.0 breaths during surface intervals lasting 2.6+/−0.31 min. Mean fh at the surface was 106+/−3 beats min(−)(1). fb and fh did not change significantly over the course of surface intervals. Surface fb and fh were not clearly associated with levels of exertion, such as rapid horizontal transit or apparent foraging, or with measures of immediately previous or subsequent diving performance, such as diving duration, diving depth or swimming speed. Together, surface respiration rate and the duration of the preceding dive were significant predictors of surface interval duration. This implies that elephant seals minimize surface time spent loading oxygen depending on rates of oxygen uptake and previous depletion of stores

    The application of quasi-elastic neutron scattering to investigate hydrogen diffusion in an iron-based Fischer-Tropsch synthesis catalyst

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    Sasol Ltd., (PGRS-3) the University of Glasgow and the Engineering and Physical Sciences Research Council (EP/P505534/1) are thanked for the provision of postgraduate studentship (ALD). The STFC Rutherford Appleton Laboratory is thanked for access to neutron beam facilities (RB1720188) [26]. The Royal Society are thanked for the provision of an Industrial Fellowship (PBW).Iron-based Fischer–Tropsch synthesis (FTS) catalysts evolve in situ on exposure to synthesis gas (CO & H2) forming a mixture of iron oxides, iron carbides and carbonaceous deposits. Recently, the application of inelastic neutron scattering has shown the progressive formation of a hydrocarbonaceous overlayer during this catalyst conditioning period. The evolving nature of the catalyst alters the proportion of phases present within the catalyst, which may influence the transport of hydrogen within the reaction system. Preliminary quasi-elastic neutron scattering (QENS) measurements are used to investigate hydrogen diffusion within an un-promoted iron FTS catalyst that has experienced varying levels of time-on-stream (0, 12 and 24 h) of ambient pressure CO hydrogenation at 623 K. Measurements on the catalyst samples in the absence of hydrogen show the unreacted sample (t = 0 h) to exhibit little increase in motion over the temperature range studied, whereas the t = 12 and 24 h samples exhibit a pronounced change in motion with temperature. The contrast is attributed to the presence of the afore-mentioned hydrocarbonaceous overlayer. Measurements on the samples in the presence of liquid hydrogen show hydrogen diffusional characteristics to be modified as a function of the catalyst conditioning process but, due to the complexity of the evolving catalyst matrix, the hydrogen motion cannot be attributed to a particular phase or component of the catalyst. Problems in the use of hydrogen as a probe molecule in this instance are briefly considered. Coincident neutron diffraction studies undertaken alongside the QENS measurements confirm the transition from hematite pre-catalyst to that of Hägg carbide during the course of extended times-on-stream.Publisher PDFPeer reviewe

    Diets and Food Selection of Female Mallards and Blue-Winged Teal During Spring Migration

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    Waterfowl nutritional requirements and food availability at migration stopover habitats may differ from those at nesting or wintering areas. Although there is little information on factors that influence waterfowl diets and food selection during migration, we hypothesized that bird age and wetland density in the surrounding landscape would influence food selection. Thus, the objective of this study was to quantify mallard Anas platyrhynchos and blue-winged teal Anas discors diets during migration and evaluate effects of age and wetland density on waterfowl food selection. We collected 30 mallards and 29 blue-winged teal with food items present in esophagi from wetlands in south-central Nebraska during spring 2008 and 2009. Smartweed Polygonum spp. and barnyard grass Echinochloa spp. were the most common seeds found in both mallards and blue-winged teal, while Naididae and Chironomidae larvae were the most common invertebrates in mallard and blue-winged teal diets, respectively. Invertebrates were consumed by both species in greater proportion than available. Both mallards and blue-winged teal collected in wetland complexes selected some seeds over others, whereas birds in isolated wetlands foraged on foods in proportion to availability. After-hatch-year mallards also selected for some seeds over others, as compared with hatch-year birds, which foraged opportunistically on available foods. If after-hatch-year birds and birds in wetland complexes are able to be more selective in their diets relative to food availability at individual wetlands, they may be able to acquire and replenish lipids reserves more efficiently than hatch-year birds or birds in areas with lower wetland densities

    Hydrogen partitioning as a function of time-on-stream for an unpromoted iron-based Fischer-Tropsch synthesis catalyst applied to CO hydrogenation

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    Sasol Ltd., the EPSRC (award reference EP/P505534/1), and the University of Glasgow are thanked for the provision of a postgraduate studentship (ALD). The STFC Rutherford Appleton Laboratory is thanked for access to neutron beam facilities. The Royal Society is thanked for the provision of an Industry Fellowship (PBW).Inelastic neutron scattering (INS) is employed to examine the evolution of a promoter-free iron-based Fischer-Tropsch synthesis catalyst (∼10 g catalyst charge) that is exposed to ambient pressure CO hydrogenation at 623 K for up to 10 days time-on-stream (T-o-S). The longer reaction time is selected to better understand how the formation of a previously described hydrocarbonaceous overlayer corresponds to the catalyst conditioning process. Although the onset of pseudo steady-state reactor performance is observed at approximately 9 h T-o-S, INS establishes that the intensity of the C-H stretching mode of the sp3-hybridized component of the hydrocarbonaceous overlayer saturates at about 24 h T-o-S, while the corresponding intensity of the C-H stretching mode of the sp2-hybridized component requires 100-200 h T-o-S to achieve saturation. This novel series of measurements reveal different aspects of the complex catalyst evolutionary process to be indirectly connected with catalytic turnover.Publisher PDFPeer reviewe

    The effect of facial expression on contrast sensitivity: A behavioural investigation and extension of Hedger, Adams & Garner (2015)

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    It has been argued that rapid visual processing for fearful face expressions is driven by the fact that effective contrast is higher in these faces compared to other expressions, when the contrast sensitivity function is taken into account. This proposal has been upheld by data from image analyses, but is yet to be tested at the behavioural level. The present study conducts a traditional contrast sensitivity task for face images of various facial expressions. Findings show that visual contrast thresholds do not differ for different facial expressions We re-conduct analysis of faces’ effective contrast, using the procedure developed by Hedger, Adams and Garner, and show that higher effective contrast in fearful face expressions relies on face images first being normalised for RMS contrast. When not normalised for RMS contrast, effective contrast in fear expressions is no different, or sometimes even lower, compared to other expressions. However, the effect of facial expression on detection in a backward masking study did not depend on the type of contrast normalisation used. These findings are discussed in relation to the implications of contrast normalisation on the salience of face expressions in behavioural and neurophysiological experiments, and also the extent that natural physical differences between facial stimuli are masked during stimulus standardisation and normalisation
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