1,844 research outputs found
Insights into Due Process Reform: A Nationwide Survey of Special Education Attorneys
The federal law that guarantees an appropriate and inclusive education for children with disabilities relies on private enforcement; parents concerned about the inadequacy of their childrenâs education can take advantage of an administrative hearing to seek resolution of disputes with the childâs school district. While conceived in the Individuals with Disabilities Education Act (IDEA) as a prompt and informal tool, evidence suggests that special education due process hearings have become overly complex, prohibitively expensive, and excessively lengthy, thus limiting their accessibility and usefulness as an enforcement mechanism.
Despite numerous studies highlighting the flaws of special education due process, few have taken advantage of a particularly important resource for crafting reform proposals: the attorneys who practice special education law. Tapping into practitionersâ lived experiences of special education due process provides us with a clearer sense of how the due process system plays out in practice and, importantly, how differing perceptions of the systemâs flaws may facilitate or impede attempts to build support for particular reforms.
In addition to cataloging various features of the due process system that differ from state to state, this article reports data from a nationwide survey of practicing special education lawyers that elicited their views about the effectiveness of the due process system. The most salient observation obtained from the survey is that the attorneyâs clientâbe it the parents or the school districtâstrongly shapes the attorneyâs perceptions of the systemâs flaws and targets for change. Yet the results also suggest a number of reforms that could improve and streamline the system while garnering support from both parents and school districts. Recommendations include (1) more rigorous training of hearing officers, both in terms of case management and substantive special education law; (2) publication at the state level of more comprehensive and uniform standards for procedure, discovery, and admission of evidence; (3) development of additional funding sources for parent attorneys and expert witnesses; and (4) state review of rules with an eye toward greater procedural simplicity
Coherent Phonons in Carbon Nanotubes and Graphene
We review recent studies of coherent phonons (CPs) corresponding to the
radial breathing mode (RBM) and G-mode in single-wall carbon nanotubes (SWCNTs)
and graphene. Because of the bandgap-diameter relationship, RBM-CPs cause
bandgap oscillations in SWCNTs, modulating interband transitions at terahertz
frequencies. Interband resonances enhance CP signals, allowing for chirality
determination. Using pulse shaping, one can selectively excite
speci!c-chirality SWCNTs within an ensemble. G-mode CPs exhibit
temperature-dependent dephasing via interaction with RBM phonons. Our
microscopic theory derives a driven oscillator equation with a
density-dependent driving term, which correctly predicts CP trends within and
between (2n+m) families. We also find that the diameter can initially increase
or decrease. Finally, we theoretically study the radial breathing like mode in
graphene nanoribbons. For excitation near the absorption edge, the driving term
is much larger for zigzag nanoribbons. We also explain how the armchair
nanoribbon width changes in response to laser excitation.Comment: 48 pages, 41 figure
Kinetics of 99Tc speciation in aerobic soils
© 2019 The Authors Technetium-99 is a significant and long-lived component of spent nuclear fuel relevant to long-term assessments of radioactive waste disposal. Whilst 99Tc behaviour in poorly aerated environments is well known, the long-term bioavailability in aerobic soils following direct deposition or transport to the surface is less well understood. This work addresses two questions: (i) to what extent do soil properties control 99Tc kinetics in aerobic soils and (ii) over what experimental timescales must 99Tc kinetics be measured to make reliable long-term predictions of impact in the terrestrial environment? Soil microcosms spiked with 99TcO4â were incubated for 2.5 years and 99Tc transformations were periodically monitored by a sequential extraction, which enabled quantification of the reaction kinetics. Reduction in soluble 99Tc was slow and followed a double exponential kinetic model including a fast component enhanced by low pH, a slow component controlled by pH and organic matter, and a persistently soluble 99Tc fraction. Complexation with soil humus was key to the progressive immobilisation of 99Tc. Evidence for slow transfer to an unidentified âsinkâ was found, with estimated decadal timeframes. Our data suggest that short-term experiments may not reliably predict long-term 99Tc solubility in soils with low to moderate organic matter contents
Genome-wide association study of male sexual orientation
Family and twin studies suggest that genes play a role in male sexual orientation. We conducted a genome-wide association study (GWAS) of male sexual orientation on a primarily European ancestry sample of 1,077 homosexual men and 1,231 heterosexual men using Affymetrix single nucleotide polymorphism (SNP) arrays. We identified several SNPs with p < 10 -5 , including regions of multiple supporting SNPs on chromosomes 13 (minimum p = 7.5 Ă 10 -7 ) and 14 (p = 4.7 Ă 10 -7 ). The genes nearest to these peaks have functions plausibly relevant to the development of sexual orientation. On chromosome 13, SLITRK6 is a neurodevelopmental gene mostly expressed in the diencephalon, which contains a region previously reported as differing in size in men by sexual orientation. On chromosome 14, TSHR genetic variants in intron 1 could conceivably help explain past findings relating familial atypical thyroid function and male homosexuality. Furthermore, skewed X chromosome inactivation has been found in the thyroid condition, Graves' disease, as well as in mothers of homosexual men. On pericentromeric chromosome 8 within our previously reported linkage peak, we found support (p = 4.1 Ă 10 -3 ) for a SNP association previously reported (rs77013977, p = 7.1 Ă 10 -8 ), with the combined analysis yielding p = 6.7 Ă 10 -9 , i.e., a genome-wide significant association
Using chemical fractionation and speciation to describe uptake of technetium, iodine and selenium by Agrostis capillaris and Lolium perenne
© 2019 Elsevier Ltd To understand the dynamic mechanisms governing soil-to-plant transfer of selenium (Se), technetium-99 (99Tc) and iodine (I), a pot experiment was undertaken using 30 contrasting soils after spiking with 77Se, 99Tc and 129I, and incubating for 2.5 years. Two grass species (Agrostis capillaris and Lolium perenne) were grown under controlled conditions for 4 months with 3 cuts at approximately monthly intervals. Native (soil-derived) 78Se and127I, as well as spiked 77Se, 99Tc and 129I, were assayed in soil and plants by ICP-MS. The grasses exhibited similar behaviour with respect to uptake of all three elements. The greatest uptake observed was for 99Tc, followed by 77Se, with least uptake of 129I, reflecting the transformations and interactions with soil of the three isotopes. Unlike soil-derived Se and I, the available pools of 77Se, 99Tc and 129I were substantially depleted by plant uptake across the three cuts with lower concentrations observed in plant tissues in each subsequent cut. Comparison between total plant offtake and various soil species suggested that 77SeO42â, 99TcO4â and 129IO3â, in soluble and adsorbed fractions were the most likely plant-available species. A greater ratio of 127I/129I in the soil solid phase compared to the solution phase confirmed incomplete mixing of spiked 129I with native 127I in the soil, despite the extended incubation period, leading to poor buffering of the spiked available pools. Compared to traditional expressions of soil-plant transfer factor (TFtotal), a transfer factor (TFavailable) expressed using volumetric concentrations of speciated âavailableâ fractions of each element showed little variation with soil properties
Genetic and Environmental Influences on Female Sexual Orientation, Childhood Gender Typicality and Adult Gender Identity
Background: Human sexual orientation is influenced by genetic and non-shared environmental factors as are two important psychological correlates â childhood gender typicality (CGT) and adult gender identity (AGI). However, researchers have been unable to resolve the genetic and non-genetic components that contribute to the covariation between these traits, particularly in women. Methodology/Principal Findings: Here we performed a multivariate genetic analysis in a large sample of British female twins (N = 4,426) who completed a questionnaire assessing sexual attraction, CGT and AGI. Univariate genetic models indicated modest genetic influences on sexual attraction (25%), AGI (11%) and CGT (31%). For the multivariate analyses, a common pathway model best fitted the data. Conclusions/Significance: This indicated that a single latent variable influenced by a genetic component and common nonshared environmental component explained the association between the three traits but there was substantial measurement error. These findings highlight common developmental factors affecting differences in sexual orientation
Need for Alloparental Care and Attitudes Toward Homosexuals in 58 Countries: Implications for the Kin Selection Hypothesis
Homosexuality is an evolutionary puzzle. Many theories attempt to explain how a trait undermining individual reproduction can be maintained, but experimental testing of their predictions remains scarce. The kin selection hypothesis (KSH) is an important theoretical framework to account for the evolution of human homosexuality, postulating that its direct cost to reproduction can be offset by inclusive fitness gains through alloparental assistance to kin. Consistent evidence in support of the KSH has only been garnered from research on Samoan faâafafine (i.e. feminine, same-sex attracted males), whereas research in numerous industrialized societies has repeatedly failed to secure empirical support for the theory. Here, we propose an alternative test of the KSH by investigating how need for alloparental care influences womenâs attitudes toward homosexuality (AtH). AtH would influence the likelihood of women receiving alloparental care from homosexual kin. We applied logistic regression analysis to a large dataset (17,295 women in 58 countries) derived from the World Values Survey. As predicted by the KSH, women who are potentially most in need of alloparental support exhibit significantly more positive attitudes toward homosexuals. For single mothers who expressed parental care concerns, each additional child mothered was associated with an increase of 1.24 in their odds of exhibiting positive attitudes toward homosexuals. Our study is the first to provide circumstantial evidence in support of the KSH on a global scale
Measurement of Ï c1 and Ï c2 production with sâ = 7 TeV pp collisions at ATLAS
The prompt and non-prompt production cross-sections for the Ï c1 and Ï c2 charmonium states are measured in pp collisions at sâ = 7 TeV with the ATLAS detector at the LHC using 4.5 fbâ1 of integrated luminosity. The Ï c states are reconstructed through the radiative decay Ï c â J/ÏÎł (with J/Ï â ÎŒ + ÎŒ â) where photons are reconstructed from Îł â e + e â conversions. The production rate of the Ï c2 state relative to the Ï c1 state is measured for prompt and non-prompt Ï c as a function of J/Ï transverse momentum. The prompt Ï c cross-sections are combined with existing measurements of prompt J/Ï production to derive the fraction of prompt J/Ï produced in feed-down from Ï c decays. The fractions of Ï c1 and Ï c2 produced in b-hadron decays are also measured
Measurement of the production of a W boson in association with a charm quark in pp collisions at âs = 7 TeV with the ATLAS detector
The production of a W boson in association with a single charm quark is studied using 4.6 fbâ1 of pp collision data at sâ = 7 TeV collected with the ATLAS detector at the Large Hadron Collider. In events in which a W boson decays to an electron or muon, the charm quark is tagged either by its semileptonic decay to a muon or by the presence of a charmed meson. The integrated and differential cross sections as a function of the pseudorapidity of the lepton from the W-boson decay are measured. Results are compared to the predictions of next-to-leading-order QCD calculations obtained from various parton distribution function parameterisations. The ratio of the strange-to-down sea-quark distributions is determined to be 0.96+0.26â0.30 at Q 2 = 1.9 GeV2, which supports the hypothesis of an SU(3)-symmetric composition of the light-quark sea. Additionally, the cross-section ratio Ï(W + +cÂŻÂŻ)/Ï(W â + c) is compared to the predictions obtained using parton distribution function parameterisations with different assumptions about the sâsÂŻÂŻÂŻ quark asymmetry
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