472 research outputs found

    On Educational Outcomes in an Urban School District

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    Urban school districts face an enormous challenge. They are confronted with high levels of poverty and minority students who at high-risk for educational failure. To compound this, financial resources are lacking in improving these dire conditions. Thus, in a situation where increased budgetary support is no longer accessible, one question remains: What will make a difference? Chapter 1 suggests a first strategy. If district administrators or school principals could shift classroom composition to increase student achievement, then perhaps this managerial approach could improve urban education under extremely strict financial constraints. Using the framework of the education production function and two quasi-experiments, this investigation has identified status quo peer effects in Philadelphia’s elementary school classrooms over six years of observations. Holding fixed students and classrooms, Chapter 2 then asks what contributes to school effectiveness at the level of the institution. It does so by constructing two unique, quantifiable measures of school quality based on the empirical model from Chapter 1. The results indicate that institutional-level resources are significantly related to school quality across three categories (programs, personnel, and school environment) and within both testing subject areas. Based on the covariates analyzed in the first two chapters, Chapter 3 evaluates if and why there is significant variation in standardized testing performance for students in a single urban school district. Incorporating variables into a three-tiered hierarchical linear model of student achievement explains the majority of the between classroom and between school variance, though only half of the within classroom variance

    The Fermionic Density-functional at Feshbach Resonance

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    We consider a dilute gas of neutral unpolarized fermionic atoms at zero temperature.The atoms interact via a short range (tunable) attractive interaction. We demonstrate analytically a curious property of the gas at unitarity. Namely, the correlation energy of the gas, evaluated by second order perturbation theory, has the same density dependence as the first order exchange energy, and the two almost exactly cancel each other at Feshbach resonance irrespective of the shape of the potential, provided (μrs)>>1(\mu r_s) >> 1. Here (μ)1(\mu)^{-1} is the range of the two-body potential, and rsr_s is defined through the number density n=3/(4πrs3)n=3/(4\pi r_s^3). The implications of this result for universality is discussed.Comment: Five pages, one table. accepted for publication in PR

    Remembrance of Odors Past Human Olfactory Cortex in Cross-Modal Recognition Memory

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    AbstractEpisodic memory is often imbued with multisensory richness, such that the recall of an event can be endowed with the sights, sounds, and smells of its prior occurrence. While hippocampus and related medial temporal structures are implicated in episodic memory retrieval, the participation of sensory-specific cortex in representing the qualities of an episode is less well established. We combined functional magnetic resonance imaging (fMRI) with a cross-modal paradigm, where objects were presented with odors during memory encoding. We then examined the effect of odor context on neural responses at retrieval when these same objects were presented alone. Primary olfactory (piriform) cortex, as well as anterior hippocampus, was activated during the successful retrieval of old (compared to new) objects. Our findings indicate that sensory features of the original engram are preserved in unimodal olfactory cortex. We suggest that reactivation of memory traces distributed across modality-specific brain areas underpins the sensory qualities of episodic memories

    Emotional and Adrenocortical Responses of Infants to the Strange Situation: The Differential Function of Emotional Expression

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    The aim of the study was to investigate biobehavioural organisation in infants with different qualities of attachment. Quality of attachment (security and disorganisation), emotional expression, and adrenocortical stress reactivity were investigated in a sample of 106 infants observed during Ainsworth’s Strange Situation at the age of 12 months. In addition, behavioural inhibition was assessed from maternal reports. As expected, securely attached infants did not show an adrenocortical response. Regarding the traditionally defined insecurely attached groups, adrenocortical activation during the strange situation was found for the ambivalent group, but not for the avoidant one. Previous ndings of increased adrenocortical activity in disorganised infants could not be replicated. In line with previous ndings, adrenocortical activation was most prominent in insecure infants with high behavioural inhibition indicating the function of a secure attachment relationship as a social buffer against less adaptive temperamental dispositions. Additional analyses indicated that adrenocortical reactivity and behavioural distress were not based on common activation processes. Biobehavioural associations within the different attachment groups suggest that biobehavioural processes in securely attached infants may be different from those in insecurely attached and disorganised groups. Whereas a coping model may be applied to describe the biobehavioural organisation of secure infants, an arousal model explanation may be more appropriate for the other groups

    Inclusive education in progress: policy evolution in four European countries

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    This paper seeks to compare the evolution of inclusive education policy in the four countries of an EU-funded research project (QualiTYDES) operating under the shared policy environment of the UN, EU and European Commission. A shared policy cannot of course be assumed to result in common legislative or provisional outcomes at national level. The different sociocultural, political, historical and economic contexts in each country shape its journey towards ‘compliance’ with an international convention (both pre- and post-ratification), and neither the route nor the destination can be assumed to be shared, given the scope for different interpretations of the same texts. This paper places the implementation trajectories of four European countries side by side as they attempt to move towards ‘inclusive’ education systems. Following a brief overview of the international education policy environment relating to the education of people with disabilities, we describe the national education policy responses in Ireland, Austria, Spain and Czech Republic in recent decades, including both legislation pertaining to special educational need and implementation of policies in practice. The comparison highlights the different manifestations of inclusive education current in each country, and also explores the challenges which have arisen as individual countries attempt to align international policy with provision in existing education systems, each with their own legacy interests, pressures and priorities. Examples of ‘gaps’ in this alignment are where learners with disabilities/SEN are likely to be failed, and represent the critical points at which barriers to fully inclusive education arise and negatively impact opportunity over the life course.The QualiTYDES research project was supported by the European Science Foundation [grant number 09-ECRP-032]; Austrian Science Fund (FWF) [grant number I343]; Irish Research Council (IRC, formerly IRCHSS) [grant number IRCHSS 09-ECRP-032]; Ministerio de Economía y Competitividad (MINECO) [grant number EUI-2010-04,213]; and Czech Science Foundation [grant number P407/11/2009].Peer reviewe

    Overcoming artificial broadening in Gd³⁺–Gd³⁺ distance distributions arising from dipolar pseudo-secular terms in DEER experiments

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    By providing accurate distance measurements between spin labels site-specifically attached to bio-macromolecules, double electron–electron resonance (DEER) spectroscopy provides a unique tool to probe the structural and conformational changes in these molecules. Gd3+-tags present an important family of spin-labels for such purposes, as they feature high chemical stability and high sensitivity in high-field DEER measurements. The high sensitivity of the Gd3+ ion is associated with its high spin (S = 7/2) and small zero field splitting (ZFS), resulting in a narrow spectral width of its central transition at high fields. However, under the conditions of short distances and exceptionally small ZFS, the weak coupling approximation, which is essential for straightforward DEER data analysis, becomes invalid and the pseudo-secular terms of the dipolar Hamiltonian can no longer be ignored. This work further explores the effects of pseudo-secular terms on Gd3+–Gd3+ DEER measurements using a specifically designed ruler molecule; a rigid bis-Gd3+-DOTA model compound with an expected Gd3+–Gd3+ distance of 2.35 nm and a very narrow central transition at the W-band (95 GHz). We show that the DEER dipolar modulations are damped under the standard W-band DEER measurement conditions with a frequency separation, Δν, of 100 MHz between the pump and observe pulses. Consequently, the DEER spectrum deviates considerably from the expected Pake pattern. We show that the Pake pattern and the associated dipolar modulations can be restored with the aid of a dual mode cavity by increasing Δν from 100 MHz to 1.09 GHz, allowing for a straightforward measurement of a Gd3+–Gd3+ distance of 2.35 nm. The increase in Δν increases the contribution of the |−5/2〉 → |−3/2〉 and |−7/2〉 → |−5/2〉 transitions to the signal at the expense of the |−3/2 〉 → |−1/2〉 transition, thus minimizing the effect of dipolar pseudo-secular terms and restoring the validity of the weak coupling approximation. We apply this approach to the A93C/N140C mutant of T4 lysozyme labeled with two different Gd3+ tags that have narrow central transitions and show that even for a distance of 4 nm there is still a significant (about two-fold) broadening that is removed by increasing Δν to 636 MHz and 898 MHz.This research was supported by the Israeli Science Foundation (grant 334/14) and made possible in part by the historic generosity of the Harold Perlman Family. D. G. holds the Erich Klieger professorial chair in Chemical Physic

    Щодо утворення сімейств атомарних радіальних базисних функцій

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    Наведено схему побудови сімейств атомарних радіальних базисних функцій, які є нескінченно диференційовними фінітними розв'язками функціонально-диференціальних рівнянь, породжених операторами Лапласа та Гельмгольца.The scheme of building a family of atomic radial basis functions which are infinitely differentiable finite solutions of the functional-differential equations containing the Laplace and Helmholtz operators is introduced
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