7,999 research outputs found
Stable photosensor amplifiers
Minimization of common mode effects in differential amplifier arrangement which processes signals from two high impedance photosensors is achieved by connecting one photosensor in feedback loop of amplifier and using field effect transistors in the input circuit
A Multimodal Analysis of Teacher-Student Interactions in Reading Recovery Writing Sessions
The day-to-day use of language and social actions in the classroom represents different modes of communication and are used as tools to negotiate the academic demands of the curriculum (Bodrova & Leong, 2007; Vygotsky, 1986). Teachers and students rely on verbal and nonverbal modes of communication to navigate teaching and learning in the classroom (Johnston, 2004; Lose, 2008; Mercer, 2008). Thus, a range of communicative interactions were examined through the lens of sociocultural theory within a worldview of constructivism as teachers and children engaged in learning. The purpose of this study was to identify the modes through which teachers and students communicated and interacted to co-construct meaning, and the extent to which these modes were read, interpreted, and understood by each other in a Reading Recovery writing lesson. The following questions guided the research: What modes do teachers and students use to communicate in the writing portion of Reading Recovery lessons? To what extent do teachers and students read, interpret, and understand each other’s modal interactions in the writing portion of Reading Recovery lessons? What modal adjustments do teachers make to scaffold and adapt instruction for student learning?
This qualitative multi-case study design (Yin, 2014) investigated different modes of communication used with Reading Recovery teachers and their respective students in a one-on-one instructional setting focused on writing. Data collection included field notes, audio/video recordings, student work samples, and the researcher’s journal. Data was analyzed using multimodal interaction analysis (Norris, 2004) along with Navarro (2008) who also studies body language. The study found literacy learning involves a complex set of communicative practices and Reading Recovery teachers and students used a range of modes to communicate and respond to each other in the writing portion of the lesson. These modal responses foster or inhibit the co-construction of meaning in teaching and learning. This study adds to the literature that considers interactional and social dimensions of learning for students who struggle with some aspect of literacy learning thus preventing literacy failure and referral to special education
Fail-safe bidirectional valve driver
Cross-coupled diodes are added to commonly used bidirectional valve driver circuit to protect circuit and power supply. Circuit may be used in systems requiring fail-safe bidirectional valve operation, particularly in chemical- and petroleum-processing control systems and computer-controlled hydraulic or pneumatic systems
Kondo Problem and Related One-Dimensional Quantum Systems: Bethe Ansatz Solution and Boundary Conformal Field Theory
We review some exact results on Kondo impurity systems derived from
Bethe-ansatz solutions and boundary conformal field theory with particular
emphasis on universal aspects of the phenomenon. The finite-size spectra
characterizing the low-energy fixed point are computed from the Bethe-ansatz
solutions of various models related to the Kondo problem. Using the finite-size
scaling argument, we investigate their exact critical properties. We also
discuss that a universal relation between the Kondo effect and the impurity
effect in one-dimensional quantum systems usefully expedites our understanding
of these different phenomena.Comment: 6 pages, no figure
Quasiperpendicular high Mach number Shocks
Shock waves exist throughout the universe and are fundamental to
understanding the nature of collisionless plasmas. Reformation is a process,
driven by microphysics, which typically occurs at high Mach number
supercritical shocks. While ongoing studies have investigated this process
extensively both theoretically and via simulations, their observations remain
few and far between. In this letter we present a study of very high Mach number
shocks in a parameter space that has been poorly explored and we identify
reformation using in situ magnetic field observations from the Cassini
spacecraft at 10 AU. This has given us an insight into quasi-perpendicular
shocks across two orders of magnitude in Alfven Mach number (MA) which could
potentially bridge the gap between modest terrestrial shocks and more exotic
astrophysical shocks. For the first time, we show evidence for cyclic
reformation controlled by specular ion reflection occurring at the predicted
timescale of ~0.3 {\tau}c, where {\tau}c is the ion gyroperiod. In addition, we
experimentally reveal the relationship between reformation and MA and focus on
the magnetic structure of such shocks to further show that for the same MA, a
reforming shock exhibits stronger magnetic field amplification than a shock
that is not reforming.Comment: Accepted and Published in Physical Review Letters (2015
Transport Properties of the One Dimensional Ferromagnetic Kondo Lattice Model : A Qualitative Approach to Oxide Manganites
The transport properties of the ferromagnetic Kondo lattice model in one
dimension are studied via bosonization methods. The antiferromagnetic
fluctuations, which normally appear because of the RKKY interactions, are
explicitly taken into account as a direct exchange between the ``core'' spins.
It is shown that in the paramagnetic regime with the local antiferromagnetic
fluctuations, the resistivity decays exponentially as the temperature increases
while in the ferromagnetic regime the system is an almost perfect conductor. %A
non-perturbative description of localized spin polarons %in the paramagnetic
region is obtained.
The effect of a weak applied field is discussed to be reduced to the case of
the ferromagnetic state leading to band splitting. The qualitative relevance of
the results for the problem of the Oxide Manganites is emphasized.Comment: 4 pages, REVTe
A study to assess COPD Symptom-based Management and to Optimise treatment Strategy in Japan (COSMOS-J) based on GOLD 2011
Background and objective: The Global initiative for chronic Obstructive Lung Disease(GOLD) Committee has proposed a chronic obstructive pulmonary disease (COPD) assessment framework focused on symptoms and on exacerbation risk. This study will evaluate a symptom and exacerbation risk-based treatment strategy based on GOLD in a real-world setting in Japan. Optimal management of COPD will be determined by assessing symptoms using the COPD Assessment Test (CAT) and by assessing the frequency of exacerbations.
Methods: This study (ClinicalTrials.gov identifier: NCT01762800) is a 24-week, multicenter, randomized, double-blind, double-dummy, parallel-group study. It aims to recruit 400 patients with moderate-to-severe COPD. Patients will be randomized to receive treatment with either
salmeterol/fluticasone propionate (SFC) 50/250μg twice daily or with tiotropium bromide 18μg once daily. Optimal management of patients will be assessed at four-weekly intervals and, if patients remain symptomatic, as measured using the CAT, or experience an exacerbation, they
have the option to step up to treatment with both drugs, ie, SFC twice daily and tiotropium once daily (TRIPLE therapy). The primary endpoint of the study will be the proportion of patients who are able to remain on the randomized therapy.
Results: No data are available. This paper summarizes the methodology of the study in advance of the study starting.
Conclusion: The results of this study will help physicians to understand whether TRIPLE therapy is more effective than either treatment strategy alone in controlling symptoms and exacerbations in patients with moderate-to-severe COPD. It will also help physicians to understand the GOLD recommendation work in Japan
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