20,645 research outputs found
Recommended from our members
Teaching linguistics gotta catch ’em all: Skills grading in undergraduate linguistics
Dissatisfied with traditional grading, we developed a grading system to directly assess whether students have mastered course material. We identified the set of skills students need to master in a course and provided multiple opportunities for students to demonstrate mastery of each skill. We describe in detail how we implemented the system for two undergraduate courses, Introductory Phonetics and Phonology I. Our goals were to decrease student stress, increase student learning and make students’ study efforts more effective, increase students’ metacognitive awareness, promote a growth mindset, encourage students to aim for mastery rather than partial credit, be fairer to students facing structural and institutional disadvantages, reduce our time spent on grading, and facilitate complying with new accreditation requirements. Our own reflections and student feedback indicate that many of these goals were met
Experimental pool boiling investigations of vertical coalescence for FC-72 on silicon from an isolated artificial cavity
In this study bubble growth from an isolated artificial cavity micro-fabricated on a horizontal 380 µm thick silicon wafer was investigated. The horizontally oriented boiling surface was heated by a thin resistance heater integrated on the rear of the silicon test section. The temperature was measured using an integrated micro-sensor situated on the boiling surface with the artificial cavity located in its geometrical centre. A resistive track was used as the sensor, which when calibrated, exhibited a near-linear behaviour with increasing temperature. To conduct pool boiling experiments the test section was immersed in degassed fluorinert FC-72. Bubble nucleation, growth and detachment at different pressures were observed using high-speed imaging. Coalescence was observed at the boundary between the isolated bubble and interference regimes. The occurrence of vertical coalescence was found to be more frequent, with increasing wall superheat and decreasing pressure.
The equivalent sphere volumes of two bubbles before and after coalescence were evaluated from area measurements. It was observed that the second nucleated bubble is always smaller than its predecessor. The vapour generation appears not to stop during coalescence as the volume of the merged bubble was typically 5-18% larger than the sum of the bubble volumes just before coalescence
Some Statistical Problems with High Dimensional Financial data
For high dimensional data, some of the standard statistical techniques do not
work well. So modification or further development of statistical methods are
necessary. In this paper, we explore these modifications. We start with the
important problem of estimating high dimensional covariance matrix. Then we
explore some of the important statistical techniques such as high dimensional
regression, principal component analysis, multiple testing problems and
classification. We describe some of the fast algorithms that can be readily
applied in practice.Comment: 22 pages, 5 figure
Clinical experience with lapatinib in patients with ErbB2-overexpressing metastatic breast cancer
Severe loss-of-function mutations in the adrenocorticotropin receptor (ACTHR, MC2R) can be found in patients diagnosed with salt-losing adrenal hypoplasia
Objective: Familial glucocorticoid deficiency type I (FGD1) is a rare form of primary adrenal insufficiency resulting from recessive mutations in the ACTH receptor (MC2R, MC2R). Individuals with this condition typically present in infancy or childhood with signs and symptoms of cortisol insufficiency, but disturbances in the renin-angiotensin system, aldosterone synthesis or sodium homeostasis are not a well-documented association of FGD1. As ACTH stimulation has been shown to stimulate aldosterone release in normal controls, and other causes of hyponatraemia can occur in children with cortisol deficiency, we investigated whether MC2R changes might be identified in children with primary adrenal failure who were being treated for mineralocorticoid insufficiency.
Design: Mutational analysis of MC2R by direct sequencing.
Patients: Children (n = 22) who had been diagnosed with salt-losing forms of adrenal hypoplasia (19 isolated cases, 3 familial), and who were negative for mutations in DAX1 (NR0B1) and SF1 (NR5A1).
Results: MC2R mutations were found in three individuals or kindred (I: homozygous S74I; II: novel compound heterozygous R146H/560delT; III: novel homozygous 579-581delTGT). These changes represent severely disruptive loss-of-function mutations in this G-protein coupled receptor, including the first reported homozygous frameshift mutation. The apparent disturbances in sodium homeostasis were mild, manifest at times of stress (e.g. infection, salt-restriction, heat), and likely resolved with time.
Conclusions: MC2R mutations should be considered in children who have primary adrenal failure with apparent mild disturbances in renin-sodium homeostasis. These children may have been misdiagnosed as having salt-losing adrenal hypoplasia. Making this diagnosis has important implications for treatment, counselling and long-term prognosi
Certainly Unsupervisable States
This paper proposes an abstraction method for compositional synthesis. Synthesis is a method to automatically compute a control program or supervisor that restricts the behaviour of a given system to ensure safety and liveness. Compositional synthesis uses repeated abstraction and simplification to combat the state-space explosion problem for large systems. The abstraction method proposed in this paper finds and removes the so-called certainly unsupervisable states. By removing these states at an early stage, the final state space can be reduced substantially. The paper describes an algorithm with cubic time complexity to compute the largest possible set of removable states. A practical example demonstrates the feasibility of the method to solve real-world problems
Generalized Mittag-Leffler Distributions and Processes for Applications in Astrophysics and Time Series Modeling
Geometric generalized Mittag-Leffler distributions having the Laplace
transform is
introduced and its properties are discussed. Autoregressive processes with
Mittag-Leffler and geometric generalized Mittag-Leffler marginal distributions
are developed. Haubold and Mathai (2000) derived a closed form representation
of the fractional kinetic equation and thermonuclear function in terms of
Mittag-Leffler function. Saxena et al (2002, 2004a,b) extended the result and
derived the solutions of a number of fractional kinetic equations in terms of
generalized Mittag-Leffler functions. These results are useful in explaining
various fundamental laws of physics. Here we develop first-order autoregressive
time series models and the properties are explored. The results have
applications in various areas like astrophysics, space sciences, meteorology,
financial modeling and reliability modeling.Comment: 12 pages, LaTe
Simulation and experimental investigation of pool boiling on a silicon wafer with artificial nucleation sites
This paper reports progress on a project to develop a design tool for large arrays of nucleation sites at specified locations to achieve high rates of cooling by pool boiling. The tool will be based on an improved version of a hybrid simulation, in which the 3-D temperature field in the wall is solved numerically, along with simple sub-models for bubble-driven heat transfer that require experimental calibration. Improvements to the computer code and progress with the experiments are reported briefly. The paper focuses on the development of a sub-model for the lateral coalescence of bubbles, which is shown to cause irregularity in the bubble production by a regular array of nucleation sites
Recommended from our members
Benchmarking 2D hydraulic models for urban flood simulations
This paper describes benchmark testing of six two-dimensional (2D) hydraulic models (DIVAST, DIVASTTVD, TUFLOW, JFLOW, TRENT and LISFLOOD-FP) in terms of their ability to simulate surface flows in a densely urbanised area. The models are applied to a 1·0 km × 0·4 km urban catchment within the city of Glasgow, Scotland, UK, and are used to simulate a flood event that occurred at this site on 30 July 2002. An identical numerical grid describing the underlying topography is constructed for each model, using a combination of airborne laser altimetry (LiDAR) fused with digital map data, and used to run a benchmark simulation. Two numerical experiments were then conducted to test the response of each model to topographic error and uncertainty over friction parameterisation. While all the models tested produce plausible results, subtle differences between particular groups of codes give considerable insight into both the practice and science of urban hydraulic modelling. In particular, the results show that the terrain data available from modern LiDAR systems are sufficiently accurate and resolved for simulating urban flows, but such data need to be fused with digital map data of building topology and land use to gain maximum benefit from the information contained therein. When such terrain data are available, uncertainty in friction parameters becomes a more dominant factor than topographic error for typical problems. The simulations also show that flows in urban environments are characterised by numerous transitions to supercritical flow and numerical shocks. However, the effects of these are localised and they do not appear to affect overall wave propagation. In contrast, inertia terms are shown to be important in this particular case, but the specific characteristics of the test site may mean that this does not hold more generally
Susceptibility to tuberculosis is associated with variants in the ASAP1 gene encoding a regulator of dendritic cell migration
Human genetic factors predispose to tuberculosis (TB). We studied 7.6 million genetic variants in 5,530 people with pulmonary TB and in 5,607 healthy controls. In the combined analysis of these subjects and the follow-up cohort (15,087 TB patients and controls altogether), we found an association between TB and variants located in introns of the ASAP1 gene on chromosome 8q24 (P = 2.6 × 10−11 for rs4733781; P = 1.0 × 10−10 for rs10956514). Dendritic cells (DCs) showed high ASAP1 expression that was reduced after Mycobacterium tuberculosis infection, and rs10956514 was associated with the level of reduction of ASAP1 expression. The ASAP1 protein is involved in actin and membrane remodeling and has been associated with podosomes. The ASAP1-depleted DCs showed impaired matrix degradation and migration. Therefore, genetically determined excessive reduction of ASAP1 expression in M. tuberculosis–infected DCs may lead to their impaired migration, suggesting a potential mechanism of predisposition to TB
- …
