“I Fall Asleep in Class … But Physics Is Fascinating”: The Use of Large-Scale Longitudinal Data to Explore the Educational Experiences of Aspiring Girls in Mathematics and Physics

This article explores how students' aspirations to study mathematics or physics in post-16 education are associated with their perceptions of their education, their motivations, and the support they feel they received. The analysis is based on the responses of around 10,000 students in England in Year 8 (age 12–13) and then in Year 10 (age 14–15). The students were first surveyed during 2008–2009 and then followed up in 2010–2011. t-tests revealed a decline in their perceptions of their mathematics and physics education. Factor analyses indicated subject-specific constructs that were associated with gender aspiration groups (i.e., high-aspiring girls, high-aspiring boys, low-aspiring girls, low-aspiring boys). High-aspiring girls were more likely than low-aspiring boys to be positive about mathematics/physics education, motivation in these subjects, and support received. However, high-aspiring girls were less likely than high-aspiring boys to be encouraged by their teachers and families to continue with these subjects post-16 and had lower self-concepts, intrinsic valuations, and perceptions of lessons. Low-aspiring girls reported the least favorable views of their mathematics/physics education of all four gender aspiration groups. Findings were generally similar for mathematics and physics, although students overall responded more favorably to mathematics than to physics. The quantitative findings are illustrated with extracts from longitudinal interviews (ages 15, 16, and 17) of two high-aspiring girls.     

Polychlorinated biphenyls in indoor dust from urban dwellings of Lahore,Pakistan: Congener profile,toxicity equivalency,and human health implications

This study is the pioneer assessment of the PCBs in indoor dust particles (from air conditioners) of an urbanized megacity from South Asian. The ∑₃₅ PCB concentration ranged from 0.27 to 152.9 ng/g (mean: 24.84 ± 22.10 ng/g). The tri- and tetra-PCBs were dominant homologues, contributing 57.36% of the total PCB concentrations. The mean levels of Σ₈-dioxin-like (DL), Σ₆-indicator PCBs and WHO₂₀₀₅-TEQ for DL-PCBs were 2.22 ± 2.55 ng/g, 9.49 ± 8.04 ng/g and 4.77 ± 4.89 pg/g, respectively. The multiple linear regression indicated a significant correlation of dusting frequency (p = 1.06 × 10–04) and age of the house (p = 1.02 × 10–06) with PCB concentrations in indoor environment. The spatial variation of PCB profile revealed relatively higher concentrations from sites near to illegal waste burning spots, electrical locomotive workshops, and grid stations. Human health risk assessment of PCBs for adults and toddlers through all three exposure routes (ie, inhalation, ingestion, and dermal contact) demonstrated that toddlers were vulnerable to high cancer risk (4.32 × 10⁻⁰⁴), while adults were susceptible from low to moderate levels of risk (3.16 × 10⁻⁰⁵). Therefore, comprehensive investigations for PCBs in the indoor settings, focusing particularly on the sensitive populations with relationship to the electronic devices, transformers, and illegal waste burning sites, are recommended.     

Formation of porous α-alumina from ammonium aluminum carbonate hydroxide whiskers

Ammonium aluminum carbonate hydroxide (AACH) whiskers prepared by hydrothermal technique were employed as precursor material for development of porous alumina. After compaction of AACH whiskers at 8 bars, calcination was performed at 650?°C followed by sintering at different temperatures. The sintered samples were characterized by XRD, FTIR, SEM and mercury intrusion porosimetry. Mechanical strength was determined by compression testing. At sintering temperatures of 1200?°C to 1400?°C, the % age porosity was around 80%. At 1500?°C, the percentage porosity decreased to 71%. The as-prepared AACH consisted of bundles of whiskers with diameters as thick as 0.7?µm, while an individual whisker had a diameter of about 100?nm with an aspect ratio of about 33. A two-phase mixture consisting of θ- and α-alumina was obtained at 1100?°C, while at 1200?°C and above, single phase α-alumina was formed. θ-alumina retained the bundle-like morphology. However, transformation to α-alumina was accompanied by formation of bead-like morphology. These beads were joined together through necks/stems within the whiskers as well as across the parallel-lying whiskers. These necks grew at 1300?°C to form aggregates with smooth surfaces. At 1400?°C, these aggregates started joining with each other by neck formation and at 1500?°C, a three-dimensional network was formed. For sintering temperatures of up to 1400?°C, pores with sizes around 260?nm were very stable. At 1500?°C, significant pore growth took place along with an overall densification. Therefore, number of pores with sizes of around 260?nm decreased and those with sizes around 10?µm, 1?µm and 5?nm increased. The compression strength of samples sintered at 1100?°C to 1300?°C was in the range of 3.4–4.3?MPa. At 1400?°C, the strength increased to 5.2?MPa, while at 1500?°C, it jumped to 10.8?MPa due to the formation of three-dimensional network.     

Statistical optimization and characterization of pH-independent extended-release drug delivery of cefpodoxime proxetil using Box–Behnken design

The aim of this study was to develop and optimize the pH-independent extended-release (ER) formulations of cefpodoxime proxetil (CP) using response surface methodology by employing a 3-factor, 3-level Box–Behnken statistical design. The independent variables studied were the amount of hydroxypropyl methylcellulose (HPMC K4M), sodium alginate (SA) and microcrystalline cellulose (MCC). The drug release percent at 2, 4, 8, 14 and 24 h were the target responses and were restricted to 15–30, 35–55, 55–75, 75–90 and 90–110%, respectively. The response surface methodology and multiple response optimizations utilizing a polynomial equation were used to search for the optimal formulation with a specific release rate at different time intervals. The results showed that the effect of combination of HPMC K4M and SA was the most influencing factor on the drug release from ER matrix tablets. The mechanism of drug release from ER tablets was dependent on the added amount of SA. Validation of the optimization technique demonstrated the reliability of the model. The optimized formulation containing 25% HPMC, 15.14% SA, and 20.14% MCC was prepared according to the software determined levels. DSC and FTIR studies combined with the stability study of the optimized formulation proved the integrity of the developed formulation. The Box–Behnken experimental design facilitated the formulation and optimization of extended release hydrophilic matrix systems of CP in a short period of time and with the fewest number of experiments.     

IFN-tau suppresses both the autoreactive humoral and cellular immune responses and induces stable remission in mice with chronic experimental allergic encephalomyelitis

PURPOSE: The purpose of this study was to compare attitudes toward violence and weapon-carrying among seventh-grade students in three dissimilar U.S. communities. A second focus was to determine students' understanding of their parents' violence-related guidance and behavior. METHODS: Five hundred sixty-seven seventh-grade students (48% male, 46% white, 35% African-American, 13% Latino) completed a self-administered questionnaire in May or October 1991. RESULTS: Thirty-four percent of the students had fought at least once, and 7% more than four times during the previous month. Also, within that period, 5% had skipped school owing to fear of violence. Students whose parents used nonviolent disciplinary techniques fought less frequently than those whose parents relied on hitting and more violent disciplinary methods (p < 0.001). Fighting was significantly more common among students who believe their parents want them to fight if insulted (p = 0.001). Students who reported that they try to stay out of fights usually succeeded (p = 0.001). Those students who more frequently participated in and observed fighting were more likely to carry a weapon (p = 0.001). CONCLUSIONS: Fighting is a frequent occurrence in the lives of seventh-grade students. Students' understanding of their parents' attitudes and behavior correlate strongly with violent behavior. While many students feel that weapons confer safety, those students who actually carry weapons are much more likely to fight.     

Model predictive control of an industrial pyrolysis gasoline hydrogenation reactor

This study focuses on the implementation of a nonlinear model predictive control (MPC) algorithm for controlling an industrial fixed-bed reactor where hydrogenations of raw pyrolysis gasoline occur. An orthogonal collocation method is employed to approximate the original reactor model consisting of a set of partial differential equations. The approximate model obtained is used in the synthesis of a MPC controller to control the temperature rising across a catalyst bed within the reactor. In the MPC algorithm, a sequential optimization approach is used to solve an open-loop optimal control problem. Feedback information is incorporated in the MPC to compensate for modeling error and unmeasured disturbances. The control studies are demonstrated in cases of set point tracking and disturbance rejection.     

Development of specific cutting energy map for sustainable turning: a study of Al 6061 T6 from conventional to high cutting speeds

This study presents the development of a novel Specific Cutting Energy (SCE) based process map for turning of Al 6061 T6 alloy from conventional to high-sp     

Intracerebrally injected monohydroxy and other C24 steroid acids as demyelinating agents in the guinea pig

Sodium salts of lithocholic acid (3α-hydroxy-5β-cholanoic acid), 5β-cholanoic acid, Δ⁵-cholenoic acid and 3-keto-5β-cholanoic acid injected intracerebrally into guinea pigs in doses of 1 mg or higher produced periventricular demyelination. 24-¹⁴C-sodium lithocholate was rapidly released from the brain (only traces remained 2 hr after injection) if injected in quantities ranging from 2 μg to 5 mg. This rapid elimination is believed to account for the relatively high dose of lithocholate required for producing demyelination, and may also account for the limited demyelinating capacity of the other acids injected intracerebrally.     

Correction to: Deep learning approaches for speech emotion recognition: state of the art and research challenges

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