Time-varying Learning and Content Analytics via Sparse Factor Analysis

We propose SPARFA-Trace, a new machine learning-based framework for time-varying learning and content analytics for education applications. We develop a novel message passing-based, blind, approximate Kalman filter for sparse factor analysis (SPARFA), that jointly (i) traces learner concept knowledge over time, (ii) analyzes learner concept knowledge state transitions (induced by interacting with learning resources, such as textbook sections, lecture videos, etc, or the forgetting effect), and (iii) estimates the content organization and intrinsic difficulty of the assessment questions. These quantities are estimated solely from binary-valued (correct/incorrect) graded learner response data and a summary of the specific actions each learner performs (e.g., answering a question or studying a learning resource) at each time instance. Experimental results on two online course datasets demonstrate that SPARFA-Trace is capable of tracing each learner's concept knowledge evolution over time, as well as analyzing the quality and content organization of learning resources, the question-concept associations, and the question intrinsic difficulties. Moreover, we show that SPARFA-Trace achieves comparable or better performance in predicting unobserved learner responses than existing collaborative filtering and knowledge tracing approaches for personalized education

Quantitative study of calcium uptake by tumorigenic bone (TE-85) and neuroblastoma × glioma (NG108-15) cells exposed to extremely-low-frequency (ELF) electric fields

AbstractTo verify the effect of cell culture state on frequency dependent increase in proliferation as well as Ca2+ flux across the plasma membrane, tumorigenic bone (TE-85) and neuroblastoma × glioma (NG108-15) cells cultured in the presence of fetal bovine serum (FBS) were exposed to capacitively coupled electric (CCEF) fields in the extremely low frequency (ELF) range of 10 to 18 Hz. [3H]Thymidine incorporation and 45Ca2+ uptake were used as endpoints. TE-85 cells cultured in the presence of 10% FBS did not exhibit a frequency dependent increase in proliferation in contrast to previous studies under growth arrested culture conditions, in which the cells were deprived of FBS. However, both TE-85 and NG108-15 cells had an increase in 45Ca2+ uptake in response to a 16 Hz 18.3 mV/cm CCEF. Fura-2 digital imaging microscopy was used to verify addition of 0.5 mM La3+ and 0.5 mM ionomycin as negative and positive controls, respectively. Imaging microscopy data was combined with 45Ca2+ incorporation results to quantify free intracellular calcium ([Ca2+]i) increase in response to CCEF exposure. TE-85 [Ca2+]i increased from 140 to 189–210 nM where as NG108-15 [Ca2+]i increased from 67 to 189–210 nM. These results suggested that serum deprivation may be a requirement for a frequency dependent increase in proliferation in TE-85 cells but is not necessary for the electric field induced increase in 45Ca2+ uptake in both TE-85 adn NG108 cells. The present study also represents the first demonstration of increased45Ca2+ uptake by neuroblastoma and/or glioma cells in response to an electric field exposure

Variation of milling and grain physical quality of dry season Pathum Thani 1 in Thailand

Pathum Thani 1 (PTT1) is a photoperiod-insensitive, aromatic Thai rice variety that is grown year-round. The rice from some locations is often priced lower than others due to sub-standard grain quality. This study sought to determine the limiting grain quality characteristic(s) in dry season PTT1 and their distribution across Thailand’s irrigated rice regions. To do so, we evaluated the milling and physical quality of milled rice grain of dry season PTT1 from 24 provinces in 5 regions in Thailand. Sixty-seven paddy rice samples were collected and evaluated for head rice yield, chalkiness, whiteness, and translucency. Head rice yield varied by region, with the highest (48.1%) found in samples from the Central region, compared to 34.5-39.7% elsewhere. Head rice chalkiness was the physical quality that varied more widely among the provinces within each region than among regions, with chalkiness at a level that would adversely affect price in more than one-half of the samples. Contrary to the general perception that chalky grain is less resistant in milling, head rice yield actually increased with total chalkiness, expressed as % chalky grain by weight. The total chalkiness correlated negatively with translucency, while the head rice chalkiness correlated positively with whiteness. Grain chalkiness was identified as the grain quality attribute of PTT1 rice that varied with location; this directly affected the price of milled rice grain, as well as indirectly through its relationship with head rice yield and visual appearance of the milled rice grai

Responses of milling quality to nitrogen and water management in modern long grain rice varieties

This study determined how nitrogen (N) fertilizer and water management affect grain yield and milling quality of 9 modern rice varieties with long, slender grain in two field experiments. The effect of N on rice grown in wetland culture was evaluated at 0, 60 and 120 kg N ha-1. In a second experiment the rice in aerobic and wetland culture were compared. The rice in both experiments were grown to maturity and evaluated for yield, head rice yield and chalkiness. Grain yield increased with increasing N application, head rice yield increased with increasing N in 8 varieties, while chalkiness was more than halved in 7 varieties. Grain N also increased with increasing N fertilizer, but high head rice yield in several varieties was associated with relatively low grain N. Under aerobic cultivation, all 9 varieties yielded less than in wetland culture, the head rice yield was lower and chalkiness was higher except in 2 varieties. In both experiments, grain yield was associated positively with head rice yield and negatively with chalkiness. Head rice yield and chalkiness were negatively associated in the water experiment but not in the N experiment. This study has shown that modern high yielding rice varieties generally respond positively to nitrogen fertilizer in better milling quality as well as in yield. Grain chalkiness of the varieties was more stable against variation in the environment than head rice yield

Approximation Algorithm for Line Segment Coverage for Wireless Sensor Network

The coverage problem in wireless sensor networks deals with the problem of covering a region or parts of it with sensors. In this paper, we address the problem of covering a set of line segments in sensor networks. A line segment ` is said to be covered if it intersects the sensing regions of at least one sensor distributed in that region. We show that the problem of finding the minimum number of sensors needed to cover each member in a given set of line segments in a rectangular area is NP-hard. Next, we propose a constant factor approximation algorithm for the problem of covering a set of axis-parallel line segments. We also show that a PTAS exists for this problem.Comment: 16 pages, 5 figures

Marine Monitoring Program: Annual Report for inshore pesticide monitoring 2018–19

[Extract] This component of the Marine Monitoring Program provides an understanding of nearshore pesticide profiles and the exposure risk to marine organisms, as a part of water quality condition on the Great Barrier Reef. Data are collected from eleven fixed monitoring sites located in four Natural Resource Management regions — the Wet Tropics (five sites: Low Isles, High Island, Normanby Island, Dunk Island and Lucinda), Burdekin (one site: Barratta Creek), Mackay-Whitsundays (four sites: Repulse Bay, Flat Top Island, Sandy Creek and Sarina Inlet) and Fitzroy (one site: North Keppel Island). The suite of pesticides monitored includes photosystem II (PSII) inhibiting herbicides (such as diuron, atrazine (and its metabolites), ametryn, hexazinone, tebuthiuron), which all affect photosynthesis, and are commonly detected due to their high usage in adjacent catchments, and their high solubility. Other pesticides monitored include those that have non-photosynthetic effects (such as imidacloprid and metolachlor) and knockdown herbicides (such as 2,4-D)

Tumor Necrosis Factor - Related Apoptosis-Inducing Ligand (TRAIL) promotes angiogenesis and ischemia- induced neovascularization via NADPH Oxidase 4 (NOX4) and Nitric Oxide - dependent mechanisms

Background — Tumor necrosis factor–related apoptosis-inducing ligand (TRAIL) has the ability to inhibit angiogenesis by inducing endothelial cell death, as well as being able to promote pro- angiogenic activity in vitro. These seemingly opposite effects make its role in ischemic disease unclear. Using Trail_/_ and wildtype mice, we sought to determine the role of TRAIL in angiogenesis and neovascularization following hindlimb ischemia. Methods and Results — Reduced vascularization assessed by real-time 3-dimensional Vevo ultrasound imaging and CD31 staining was evident in Trail_/_ mice after ischemia, and associated with reduced capillary formation and increased apoptosis. Notably, adenoviral TRAIL administration significantly improved limb perfusion, capillary density, and vascular smooth-muscle cell content in both Trail_/_ and wildtype mice. Fibroblast growth factor-2, a potent angiogenic factor, increased TRAIL expression in human microvascular endothelial cell-1, with fibroblast growth factor-2-mediated proliferation, migration, and tubule formation inhibited with TRAIL siRNA. Both fibroblast growth factor-2 and TRAIL significantly increased NADPH oxidase 4 (NOX4) expression. TRAIL-inducible angiogenic activity in vitro was inhibited with siRNAs targeting NOX4, and consistent with this, NOX4 mRNA was reduced in 3-day ischemic hindlimbs of Trail_/_ mice. Furthermore, TRAIL-induced proliferation, migration, and tubule formation was blocked by scavenging H2O2, or by inhibiting nitric oxide synthase activity. Importantly, TRAIL-inducible endothelial nitric oxide synthase phosphorylation at Ser-1177 and intracellular human microvascular endothelial cell-1 cell nitric oxide levels were NOX4 dependent. Conclusions — This is the first report demonstrating that TRAIL can promote angiogenesis following hindlimb ischemia in vivo. The angiogenic effect of TRAIL on human microvascular endothelial cell-1 cells is downstream of fibroblast growth factor-2, involving NOX4 and nitric oxide signaling. These data have significant therapeutic implications, such that TRAIL may improve the angiogenic response to ischemia and increase perfusion recovery in patients with cardiovascular disease and diabetes

Determination of pesticide multi-residues in green tea using a modified QuEChERS extraction and liquid chromatography tandem mass spectrometry technique

A modified QuEChERS method was developed and validated for determination of pesticide multi-residues in green tea by liquid chromatography tandem mass spectrometry. Lead acetate was first time used together with primary secondary amine and graphite carbon black to eliminate tannin, caffeine, and other pigments in tea and thus reduced the matrix effects. The method was compared to the original QuEChERS method as well as A.O.A.C. QuEChERS method. For accurate quantification, the matrix matched calibration technique was used. The method showed good performance in the concentration range from 0.01 to 1 mg kg–1. All pesticides could be quantified at and lower than 0.01 mg kg–1. Recoveries were from 70 to 120% and repeatabilities were <15% RSD depending on the compounds