176 research outputs found
Comprehension as social and intellectual practice: Rebuilding curriculum in low socioeconomic and cultural minority schools
This article reframes the concept of comprehension as a social and intellectual practice. It reviews current approaches to reading instruction for linguistically and culturally diverse and low socioeconomic students, noting an emphasis on comprehension as autonomous skills. The Four Resources model (Freebody & Luke, 1990) is used to make the case for the integration of comprehension instruction with an emphasis on student cultural and community knowledge, and substantive intellectual and sociocultural content in elementary school curricula. Illustrations are drawn from research underway on the teaching of literacy in primary schools in low SES communities
Developments in overlapping Schwarz preconditioning of high-order nodal discontinuous Galerkin discretizations
A preconditioned two-level overlapping Schwarz method for solving unstructured nodal discontinuous Galerkin discretizations of the indefinite Helmholtz problem is studied. We employ triangles in two dimensions and in a local discontinuous Galerkin (LDG) variational setting. We highlight the necessary components of the algorithm needed to achieve efficient results in the context of high-order elements and indefinite algebraic systems. More specifically, we demonstrate the importance of not only coarse-grid solution sweeps, but also for increased overlap in the subdomain solves as the order of the elements increases. In this paper, we detail the discretization strategy and offer an effective approach to solving the resulting system of equations, with numerical evidence in support
A High-Rate, Heterogeneous Data Set from the Darpa Urban Challenge
This paper describes a data set collected by MIT’s autonomous vehicle Talos during the 2007 DARPA Urban Challenge. Data from a high-precision navigation system, five cameras, 12 SICK planar laser range scanners, and a Velodyne high-density laser range scanner were synchronized and logged to disk for 90 km of travel. In addition to documenting a number of large loop closures useful for developing mapping and localization algorithms, this data set also records the first robotic traffic jam and two autonomous vehicle collisions. It is our hope that this data set will be useful to the autonomous vehicle community, especially those developing robotic perception capabilities.United States. Defense Advanced Research Projects Agency (Urban Challenge, ARPA Order No. W369/00, Program Code DIRO, issued by DARPA/CMO under Contract No. HR0011-06-C-0149
Robotically Assisted Mitral Valve Repair—Port-Only Totally Endoscopic Approach
Robotic mitral valve repair (MVR) is an emerging option to treat degenerative valve disease. Compared to open thoracotomy, robotic mitral valve surgery has been shown to afford decreased postoperative length of stay with comparable rates of mortality and morbidity. Among the variety of techniques for robotic MVR, the totally endoscopic approach remains the least invasive method to date. In this report, we describe our technique for totally endoscopic robotically-assisted MVR. In particular, we seek to highlight the use of several unique techniques in MVR. Percutaneous cannulation with use of the endoballoon is employed for cardiopulmonary bypass (CPB), thus avoiding traditional aortic cross-clamping. Moreover, intercostal nerve cryoanesthesia is performed from T3–T9 to reduce post-operative pain and aid in reducing opioid management. Barbed, nonabsorbable sutures are used throughout the procedure (for left atrial appendage closure, mitral valve annuloplasty band placement, left atrial closure, pericardial re-approximation), eliminating the need for knot-tying at several steps. We also detail the installation of two sets of neochords for mitral regurgitation and the fastening of the mitral annuloplasty band. Finally, we would like to highlight the small size of each port used in the case (eight millimeters maximum diameter). Taken together, these features of the robotic platform make it notable for its minimally invasive approach to MVR
A comparative analysis of the cultural representation of disability in school textbooks in Iran and England
The paper details the findings of a study which focused on the analysis of the cultural representation
of disability in school textbooks in Iran and England. The paper argues that whilst inclusive education
could facilitate the incorporating of disabled pupils into mainstream schools, there needs to be deeper
examination as to how this transition should take place for children aged 3-13. The paper suggests that
in such examinations school textbooks might be of significance in familiarizing non-disabled pupils,
teachers and authorities with the issues related to disability and disabled pupils
The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe
The preponderance of matter over antimatter in the early Universe, the
dynamics of the supernova bursts that produced the heavy elements necessary for
life and whether protons eventually decay --- these mysteries at the forefront
of particle physics and astrophysics are key to understanding the early
evolution of our Universe, its current state and its eventual fate. The
Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed
plan for a world-class experiment dedicated to addressing these questions. LBNE
is conceived around three central components: (1) a new, high-intensity
neutrino source generated from a megawatt-class proton accelerator at Fermi
National Accelerator Laboratory, (2) a near neutrino detector just downstream
of the source, and (3) a massive liquid argon time-projection chamber deployed
as a far detector deep underground at the Sanford Underground Research
Facility. This facility, located at the site of the former Homestake Mine in
Lead, South Dakota, is approximately 1,300 km from the neutrino source at
Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino
charge-parity symmetry violation and mass ordering effects. This ambitious yet
cost-effective design incorporates scalability and flexibility and can
accommodate a variety of upgrades and contributions. With its exceptional
combination of experimental configuration, technical capabilities, and
potential for transformative discoveries, LBNE promises to be a vital facility
for the field of particle physics worldwide, providing physicists from around
the globe with opportunities to collaborate in a twenty to thirty year program
of exciting science. In this document we provide a comprehensive overview of
LBNE's scientific objectives, its place in the landscape of neutrino physics
worldwide, the technologies it will incorporate and the capabilities it will
possess.Comment: Major update of previous version. This is the reference document for
LBNE science program and current status. Chapters 1, 3, and 9 provide a
comprehensive overview of LBNE's scientific objectives, its place in the
landscape of neutrino physics worldwide, the technologies it will incorporate
and the capabilities it will possess. 288 pages, 116 figure
piggybac- and PhiC31-Mediated Genetic Transformation of the Asian Tiger Mosquito, Aedes albopictus (Skuse)
The Asian tiger mosquito, Aedes albopictus, is a highly invasive mosquito and has spread from South East Asia to Europe, the United States and northern areas of Asia in the past 30 years. Aedes mosquitoes transmit a range of viral diseases, including dengue and chikungunya. Aedes albopictus is generally considered to be somewhat less of a concern in this regard than Aedes aegypti. However a recent mutation in the chikungunya virus dramatically increased its transmission by Aedes albopictus, causing an important outbreak in the Indian Ocean in 2006 that eventually reached Italy in 2007. This highlights the potential importance of this mosquito, which can thrive much further from the Equator than can Aedes aegypti. This paper describes the first genetic engineering of the Asian tiger mosquito. This is an essential step towards the development of genetics-based control methods against this mosquito, and also an invaluable tool for basic research. We describe both transposon-based and site-specific integration methods
Stochastic phase portraits of a damped bistable oscillator driven by colored noise.
We present measurements of the stationary, joint statistical densities of velocity and displacement in a three-dimensional system: the damped oscillator with a bistable potential driven by additive, colored noise. Approximate Fokker-Planck theories of such "higher-dimensional" systems are assessed and compared to the measurements. Because of limitations inherent in all present theories and generally available numerical techniques, analog simulators appear to offer the only effective, high-resolution means for obtaining the joint probability densities of d = 3 systems
Effect of birthweight measurement quality improvement on low birthweight prevalence in rural Ethiopia.
BACKGROUND: Low birthweight (LBW) (< 2500 g) is a significant determinant of infant morbidity and mortality worldwide. In low-income settings, the quality of birthweight data suffers from measurement and recording errors, inconsistent data reporting systems, and missing data from non-facility births. This paper describes birthweight data quality and the prevalence of LBW before and after implementation of a birthweight quality improvement (QI) initiative in Amhara region, Ethiopia. METHODS: A comparative pre-post study was performed in selected rural health facilities located in West Gojjam and South Gondar zones. At baseline, a retrospective review of delivery records from February to May 2018 was performed in 14 health centers to collect birthweight data. A birthweight QI initiative was introduced in August 2019, which included provision of high-quality digital infant weight scales (precision 5 g), routine calibration, training in birth weighing and data recording, and routine field supervision. After the QI implementation, birthweight data were prospectively collected from late August to early September 2019, and December 2019 to June 2020. Data quality, as measured by heaping (weights at exact multiples of 500 g) and rounding to the nearest 100 g, and the prevalence of LBW were calculated before and after QI implementation. RESULTS: We retrospectively reviewed 1383 delivery records before the QI implementation and prospectively measured 1371 newborn weights after QI implementation. Heaping was most frequently observed at 3000 g and declined from 26% pre-initiative to 6.7% post-initiative. Heaping at 2500 g decreased from 5.4% pre-QI to 2.2% post-QI. The percentage of rounding to the nearest 100 g was reduced from 100% pre-initiative to 36.5% post-initiative. Before the QI initiative, the prevalence of recognized LBW was 2.2% (95% confidence interval [CI]: 1.5-3.1) and after the QI initiative increased to 11.7% (95% CI: 10.1-13.5). CONCLUSIONS: A QI intervention can improve the quality of birthweight measurements, and data measurement quality may substantially affect estimates of LBW prevalence
Pangolins in global camera trap data: Implications for ecological monitoring
Despite being heavily exploited, pangolins (Pholidota: Manidae) have been subject to limited research, resulting in a lack of reliable population estimates and standardised survey methods for the eight extant species. Camera trapping represents a unique opportunity for broad-scale collaborative species monitoring due to its largely non-discriminatory nature, which creates considerable volumes of data on a relatively wide range of species. This has the potential to shed light on the ecology of rare, cryptic and understudied taxa, with implications for conservation decision-making. We undertook a global analysis of available pangolin data from camera trapping studies across their range in Africa and Asia. Our aims were (1) to assess the utility of existing camera trapping efforts as a method for monitoring pangolin populations, and (2) to gain insights into the distribution and ecology of pangolins. We analysed data collated from 103 camera trap surveys undertaken across 22 countries that fell within the range of seven of the eight pangolin species, which yielded more than half a million trap nights and 888 pangolin encounters. We ran occupancy analyses on three species (Sunda pangolin Manis javanica, white-bellied pangolin Phataginus tricuspis and giant pangolin Smutsia gigantea). Detection probabilities varied with forest cover and levels of human influence for P. tricuspis, but were low (<0.05) for all species. Occupancy was associated with distance from rivers for M. javanica and S. gigantea, elevation for P. tricuspis and S. gigantea, forest cover for P. tricuspis and protected area status for M. javanica and P. tricuspis. We conclude that camera traps are suitable for the detection of pangolins and large-scale assessment of their distributions. However, the trapping effort required to monitor populations at any given study site using existing methods appears prohibitively high. This may change in the future should anticipated technological and methodological advances in camera trapping facilitate greater sampling efforts and/or higher probabilities of detection. In particular, targeted camera placement for pangolins is likely to make pangolin monitoring more feasible with moderate sampling efforts
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