10,260 research outputs found
Developing a New Partnership
Many factors contribute to the success and impact of a Mathematics Resource Teacher on K-5 mathematics instruction. Developing a strong partnership with stakeholders and sharing a common vision for quality mathematics instruction are key factors in the successful implementation of the Mathematics Resource Teacher program. In this article, we share the experience of elementary school principal, Timothy Martino, as he prepared to open a new elementary school in August 2012. Frederick Douglass Elementary opened with a full-time, school-embedded Mathematics Resource Teacher, Mrs. Cindy Brady. Timothy Martino and Mrs. Brady developed a partnership with division-level central office staff and with the teachers of Frederick Douglass Elementary. Thus, they began the journey toward improving mathematics instruction for students through a team approach
On the transition to efficiency in Minority Games
The existence of a phase transition with diverging susceptibility in batch
Minority Games (MGs) is the mark of informationally efficient regimes and is
linked to the specifics of the agents' learning rules. Here we study how the
standard scenario is affected in a mixed population game in which agents with
the `optimal' learning rule (i.e. the one leading to efficiency) coexist with
ones whose adaptive dynamics is sub-optimal. Our generic finding is that any
non-vanishing intensive fraction of optimal agents guarantees the existence of
an efficient phase. Specifically, we calculate the dependence of the critical
point on the fraction of `optimal' agents focusing our analysis on three
cases: MGs with market impact correction, grand-canonical MGs and MGs with
heterogeneous comfort levels.Comment: 12 pages, 3 figures; contribution to the special issue "Viewing the
World through Spin Glasses" in honour of David Sherrington on the occasion of
his 65th birthda
Impact of pressure dissipation on fluid injection into layered aquifers
Carbon dioxide (CO2) capture and subsurface storage is one method for
reducing anthropogenic CO2 emissions to mitigate climate change. It is well
known that large-scale fluid injection into the subsurface leads to a buildup
in pressure that gradually spreads and dissipates through lateral and vertical
migration of water. This dissipation can have an important feedback on the
shape of the CO2 plume during injection, and the impact of vertical pressure
dissipation, in particular, remains poorly understood. Here, we investigate the
impact of lateral and vertical pressure dissipation on the injection of CO2
into a layered aquifer system. We develop a compressible, two-phase model that
couples pressure dissipation to the propagation of a CO2 gravity current. We
show that our vertically integrated, sharp-interface model is capable of
efficiently and accurately capturing water migration in a layered aquifer
system with an arbitrary number of aquifers. We identify two limiting cases ---
`no leakage' and `strong leakage' --- in which we derive analytical expressions
for the water pressure field for the corresponding single-phase injection
problem. We demonstrate that pressure dissipation acts to suppress the
formation of an advancing CO2 tongue during injection, resulting in a plume
with a reduced lateral extent. The properties of the seals and the number of
aquifers determine the strength of pressure dissipation and subsequent coupling
with the CO2 plume. The impact of pressure dissipation on the shape of the CO2
plume is likely to be important for storage efficiency and security
Strategy correlations and timing of adaptation in Minority Games
We study the role of strategy correlations and timing of adaptation for the
dynamics of Minority Games, both simulationally and analytically. Using the
exact generating functional approach a la De Dominicis we compute the phase
diagram and the behaviour of batch and on-line games with correlated
strategies, complementing exisiting replica studies of their statics. It is
shown that the timing of adaptation can be relevant; while conventional games
with uncorrelated strategies are nearly insensitive to the choice of on-line
versus batch learning, we find qualitative differences when anti-correlations
are present in the strategy assignments. The available standard approximations
for the volatility in terms of persistent order parameters in the stationary
ergodic states become unreliable in batch games under such circumstances. We
then comment on the role of oscillations and the relation to the breakdown of
ergodicity. Finally, it is discussed how the generating functional formalism
can be used to study mixed populations of so-called `producers' and
`speculators' in the context of the batch minority games.Comment: 15 pages, 13 figures, EPJ styl
Two new intermediate polars with a soft X-ray component
Aims. We analyze the first X-ray observations with XMM-Newton of 1RXS J070407.9+262501 and 1RXS 180340.0+401214, in
order to characterize their broad-band temporal and spectral properties, also in the UV/optical domain, and to confirm them as intermediate polars.
Methods. For both objects, we performed a timing analysis of the X-ray and UV/optical light curves to detect the white dwarf spin pulsations and study their energy dependence. For 1RXS 180340.0+401214 we also analyzed optical spectroscopic data to determine the orbital period. X-ray spectra were analyzed in the 0.2–10.0 keV range to characterize the emission properties of both sources.
Results. We find that the X-ray light curves of both systems are energy dependent and are dominated, below 3–5 keV, by strong pulsations at the white dwarf rotational periods (480 s for 1RXS J070407.9+262501 and 1520.5 s for 1RXS 180340.0+401214). In 1RXS 180340.0+401214 we also detect an X-ray beat variability at 1697 s which, together with our new optical spectroscopy, favours an orbital period of 4.4 h that is longer than previously estimated. Both systems show complex spectra with a hard (temperature up to 40 keV) optically thin and a soft (kT ∼ 85–100 eV) optically thick components heavily absorbed by material partially covering the X-ray sources.
Conclusions. Our observations confirm the two systems as intermediate polars and also add them as new members of the growing group of “soft” systems which show the presence of a soft X-ray blackbody component. Differences in the temperatures of the blackbodies are qualitatively explained in terms of reprocessing over different sizes of the white dwarf spot. We suggest that systems showing cooler soft X-ray blackbody components also possess white dwarfs irradiated by cyclotron radiation
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Management of functional neurological disorder.
Functional neurological disorder (FND) is a common cause of persistent and disabling neurological symptoms. These symptoms are varied and include abnormal control of movement, episodes of altered awareness resembling epileptic seizures and abnormal sensation and are often comorbid with chronic pain, fatigue and cognitive symptoms. There is increasing evidence for the role of neurologists in both the assessment and management of FND. The aim of this review is to discuss strategies for the management of FND by focusing on the diagnostic discussion and general principles, as well as specific treatment strategies for various FND symptoms, highlighting the role of the neurologist and proposing a structure for an interdisciplinary FND service
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