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

Finite Temperature Renormalization of the (ϕ3)6(\phi^3)_6- and (ϕ4)4(\phi^4)_4-Models at Zero Momentum

A self-consistent renormalization scheme at finite temperature and zero momentum is used together with the finite temperature renormalization group to study the temperature dependence of the mass and the coupling to one-loop order in the $(\phi^3)_6$- and $(\phi^4)_4$-models. It is found that the critical temperature is shifted relative to the naive one-loop result and the coupling constants at the critical temperature get large corrections. In the high temperature limit of the \phiff-model the coupling decreases.Comment: 16 pages, plain Latex, NORDITA-92/38

The solar wind effect on cosmic rays and solar activity

The relation of cosmic ray intensity to solar wind velocity is investigated, using neutron monitor data from Kiel and Deep River. The analysis shows that the regression coefficient of the average intensity for a time interval to the corresponding average velocity is negative and that the absolute effect increases monotonously with the interval of averaging, tau, that is, from -0.5% per 100km/s for tau = 1 day to -1.1% per 100km/s for tau = 27 days. For tau 27 days the coefficient becomes almost constant independently of the value of tau. The analysis also shows that this tau-dependence of the regression coefficiently is varying with the solar activity

The infrared-dark dust content of high redshift galaxies

We present a theoretical model aimed at explaining the IRX-$\beta$ relation for high redshift (z >5) galaxies. Recent observations (Capak+2015; Bouwens+2016) have shown that early Lyman Break Galaxies, although characterized by a large UV attenuation (e.g. flat UV beta slopes), show a striking FIR deficit, i.e. they are "infrared-dark". This marked deviation from the local IRX-beta relation can be explained by the larger molecular gas content of these systems. While dust in the diffuse ISM attains relatively high temperatures (Td = 45 K for typical size a=0.1 um; smaller grains can reach Td = 60 K), a sizable fraction of the dust mass is embedded in dense gas, and therefore remains cold. If confirmed, the FIR deficit might represent a novel, powerful indicator of the molecular content of high-z galaxies which can be used to pre-select candidates for follow-up deep CO observations. Thus, high-z CO line searches with ALMA might be much more promising than currently thought.Comment: 8 pages, 4 Figures, MNRAS Submitte

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

On the Mott glass in the one-dimensional half-filled charge density waves

We study the effect of impurity pinning on a one-dimensional half-filled electron system, which is expressed in terms of a phase Hamiltonian with the charge degree of freedom. Within the classical treatment, the pinned state is examined numerically. The Mott glass, which has been pointed out by Orignac et al. [Phys. Rev. Lett 83 (1999) 2378], appears in the intermediate region where the impurity potential competes with the commensurate potential. Such a state is verified by calculating the soliton formation energy, the local restoring force around the pinned state and the optical conductivity.Comment: 13 pages, 5 figures, to be published in J. Phys. Soc. Jpn. 72 No.11 (2003