Improving the Performance of the Education Sector: The Valuable, Challenging, and Limited Role of Random Assignment Evaluations

In an attempt to improve the quality of educational research, the U.S. Department of Education%u2019s Institute of Education Sciences has provided funding for 65 randomized controlled trials of educational interventions. We argue that this research methodology is more effective in providing guidance to extremely troubled schools about how to make some progress than guidance to schools trying to move from making some progress to becoming high performance organizations. We also argue that the conventional view of medical research -- discoveries made in specialized laboratories that are then tested using randomized control trials -- is an inaccurate description of the sources of advances in medical practice. Moreover, this conventional view of the sources of advances in medical practice leads to incorrect inferences about how to improve educational research. We illustrate this argument using evidence from the history of medical research on the treatment of cystic fibrosis.

On the formation of terrestrial planets in hot-Jupiter systems

We present a series of calculations aimed at examining how an inner system of planetesimals/protoplanets, undergoing terrestrial planet formation, evolves under the influence of a giant planet undergoing inward type II migration through the region bounded between 5 - 0.1 AU. We find that > 60% of the solids disk survives by being scattered by the giant planet into external orbits. Planetesimals are scattered outward almost as efficiently as protoplanets, resulting in the regeneration of a solids disk where dynamical friction is strong and terrestrial planet formation is able to resume. A simulation extended for a few Myr after the migration of the giant planet halted at 0.1 AU, resulted in an apparently stable planet of ~ 2 Earth masses forming in the habitable zone. Migration-induced mixing of volatile-rich material from beyond the `snowline' into the inner disk regions means that terrestrial planets that form there are likely to be water-rich. We predict that hot--Jupiter systems are likely to harbor water-rich terrestrial planets in their habitable zones. These planets may be detected by future planet search missions.Comment: 18 pages, 13 figures. Higher resolution pdf available at http://www.users.globalnet.co.uk/~mfogg/fogg_nelson2.pd

A Renaissance Instrument to Support Nonprofits: The Sale of Private Chapels in Florentine Churches

Catholic churches in Renaissance Florence supported themselves overwhelmingly from the contributions of wealthy citizens. The sale of private chapels within churches to individuals was a significant source of church funds, and facilitated a church construction boom. Chapel sales offered three benefits to churches: prices were usually far above cost; donor/purchasers purchased masses and other tie-in services; and they added to the magnificence of the church because donors were required to decorate chapels expensively. Donors purchased chapels for two primary reasons: to facilitate services for themselves and their families, such as masses and church burials, that would speed their departure from Purgatory; and to gain status in the community. Chapels were private property within churches, but were only occasionally used directly by their owners. The expense of chapels and their decorations made them an ideal signal for wealth, particularly since sumptuary laws limited most displays of wealth. To overcome the contributions free-rider problem, these churches sold private benefits not readily available elsewhere, namely status and salvation.

A Relative Position Code for Saccades in Dorsal Premotor Cortex

Spatial computations underlying the coordination of the hand and eye present formidable geometric challenges. One way for the nervous system to simplify these computations is to directly encode the relative position of the hand and the center of gaze. Neurons in the dorsal premotor cortex (PMd), which is critical for the guidance of arm-reaching movements, encode the relative position of the hand, gaze, and goal of reaching movements. This suggests that PMd can coordinate reaching movements with eye movements. Here, we examine saccade-related signals in PMd to determine whether they also point to a role for PMd in coordinating visual–motor behavior. We first compared the activity of a population of PMd neurons with a population of parietal reach region (PRR) neurons. During center-out reaching and saccade tasks, PMd neurons responded more strongly before saccades than PRR neurons, and PMd contained a larger proportion of exclusively saccade-tuned cells than PRR. During a saccade relative position-coding task, PMd neurons encoded saccade targets in a relative position code that depended on the relative position of gaze, the hand, and the goal of a saccadic eye movement. This relative position code for saccades is similar to the way that PMd neurons encode reach targets. We propose that eye movement and eye position signals in PMd do not drive eye movements, but rather provide spatial information that links the control of eye and arm movements to support coordinated visual–motor behavior

Detecting gravitational radiation from neutron stars using a six-parameter adaptive MCMC method

We present a Markov chain Monte Carlo technique for detecting gravitational radiation from a neutron star in laser interferometer data. The algorithm can estimate up to six unknown parameters of the target, including the rotation frequency and frequency derivative, using reparametrization, delayed rejection and simulated annealing. We highlight how a simple extension of the method, distributed over multiple computer processors, will allow for a search over a narrow frequency band. The ultimate goal of this research is to search for sources at a known locations, but uncertain spin parameters, such as may be found in SN1987A.Comment: Submitted to Classical and Quantum Gravity for GWDAW-8 proceeding

Undulation instability in a bilayer lipid membrane due to electric field interaction with lipid dipoles

Bilayer lipid membranes [BLMs] are an essential component of all biological systems, forming a functional barrier for cells and organelles from the surrounding environment. The lipid molecules that form membranes contain both permanent and induced dipoles, and an electric field can induce the formation of pores when the transverse field is sufficiently strong (electroporation). Here, a phenomenological free energy is constructed to model the response of a BLM to a transverse static electric field. The model contains a continuum description of the membrane dipoles and a coupling between the headgroup dipoles and the membrane tilt. The membrane is found to become unstable through buckling modes, which are weakly coupled to thickness fluctuations in the membrane. The thickness fluctuations, along with the increase in interfacial area produced by membrane buckling, increase the probability of localized membrane breakdown, which may lead to pore formation. The instability is found to depend strongly on the strength of the coupling between the dipolar headgroups and the membrane tilt as well as the degree of dipolar ordering in the membrane.Comment: 29 pages 8 fig

IMPACT OF MEAT IMPORTS ON LEAST-COST UNITED STATES BEEF PRODUCTION

International Relations/Trade,