Rainbow Scattering by a Cylinder with a Nearly Elliptical Cross Section

We both theoretically and experimentally examine the behavior of the first-and the second-order rainbows produced by a normally illuminated glass rod, which has a nearly elliptical cross section, as it is rotated about its major axis. We decompose the measured rainbow angle, taken as a function of the rod\u27s rotation angle, into a Fourier series and find that the rod\u27s refractive index, average ellipticity, and deviation from ellipticity are encoded primarily in the m = 0, 2, 3 Fourier coefficients, respectively. We determine these parameters for our glass rod and, where possible, compare them with independent measurements. We find that the average ellipticity of the rod agrees well with direct measurements, but that the rod\u27s diameter inferred from the spacing of the supernumeraries of the first-order rainbow is significantly larger than that obtained by direct measurement. We also determine the conditions under which the deviation of falling water droplets from an oblate spheroidal shape permits the first few supernumeraries of the second-order rainbow to be observed in a rain shower. (C) 1998 Optical Society of America

Amplification of High-Order Rainbows of a Cylinder with an Elliptical Cross Section

The intensity of high-order rainbows for normally incident light and certain rotation angles of a cylinder with an elliptical cross section is greatly amplified with respect to the intensity for a circular cross-sectional cylinder. The amplification is due to a number of the internal reflections occurring past the critical angle for total internal reflection, and the effect is especially strong for odd-order rainbows, beginning with the third order. Experimentally, the fourth-and the fifth-order rainbows of a nearly elliptical cross-sectional glass rod were observed and analyzed. (C) 1998 Optical Society of America

Parent-child interaction in Nigerian families: conversation analysis, context and culture

This paper uses a conversation analysis (CA) approach to explore parent child interaction (PCI) within Nigerian families. We illustrate how speech and language therapists (SLTs), by using CA, can tailor recommendations according to the interactional style of each individual family that are consonant with the family’s cultural beliefs. Three parent-child dyads were videoed playing and talking together in their home environments. The analysis uncovered a preference for instructional talk similar to that used in the classroom. Closer examination revealed that this was not inappropriate when considering the context of the activities and their perceived discourse role. Furthermore, this was not necessarily at the expense of responsivity or semantic contingency. The preference for instructional talk appeared to reflect deeply held cultural beliefs about the role of adults and children within the family and it is argued that the cultural paradigm is vitally important to consider when evaluating PCI. Given a potential risk that such young children may be vulnerable in terms of language difficulties, we offer an example of how PCI can be enhanced to encourage language development without disrupting the naturally occurring talk or the underlying purpose of the interaction

Systematic winter sea-surface temperature biases in the northern Arabian Sea in HiGEM and the CMIP3 models

Analysis of 20th century simulations of the High resolution Global Environment Model (HiGEM) and the Third Coupled Model Intercomparison Project (CMIP3) models shows that most have a cold sea-surface temperature (SST) bias in the northern Arabian Sea during boreal winter. The association between Arabian Sea SST and the South Asian monsoon has been widely studied in observations and models, with winter cold biases known to be detrimental to rainfall simulation during the subsequent monsoon in coupled general circulation models (GCMs). However, the causes of these SST biases are not well understood. Indeed this is one of the first papers to address causes of the cold biases. The models show anomalously strong north-easterly winter monsoon winds and cold air temperatures in north-west India, Pakistan and beyond. This leads to the anomalous advection of cold, dry air over the Arabian Sea. The cold land region is also associated with an anomalously strong meridional surface temperature gradient during winter, contributing to the enhanced low-level convergence and excessive precipitation over the western equatorial Indian Ocean seen in many models

Electron attachment to valence-excited CO

The possibility of electron attachment to the valence $^{3}\Pi$ state of CO is examined using an {\it ab initio} bound-state multireference configuration interaction approach. The resulting resonance has $^{4}\Sigma^{-}$ symmetry; the higher vibrational levels of this resonance state coincide with, or are nearly coincident with, levels of the parent $a^{3}\Pi$ state. Collisional relaxation to the lowest vibrational levels in hot plasma situations might yield the possibility of a long-lived CO$^-$ state.Comment: Revtex file + postscript file for one figur

Artificial escape from XCI by DNA methylation editing of the CDKL5 gene.

A significant number of X-linked genes escape from X chromosome inactivation and are associated with a distinct epigenetic signature. One epigenetic modification that strongly correlates with X-escape is reduced DNA methylation in promoter regions. Here, we created an artificial escape by editing DNA methylation on the promoter of CDKL5, a gene causative for an infantile epilepsy, from the silenced X-chromosomal allele in human neuronal-like cells. We identify that a fusion of the catalytic domain of TET1 to dCas9 targeted to the CDKL5 promoter using three guide RNAs causes significant reactivation of the inactive allele in combination with removal of methyl groups from CpG dinucleotides. Strikingly, we demonstrate that co-expression of TET1 and a VP64 transactivator have a synergistic effect on the reactivation of the inactive allele to levels >60% of the active allele. We further used a multi-omics assessment to determine potential off-targets on the transcriptome and methylome. We find that synergistic delivery of dCas9 effectors is highly selective for the target site. Our findings further elucidate a causal role for reduced DNA methylation associated with escape from X chromosome inactivation. Understanding the epigenetics associated with escape from X chromosome inactivation has potential for those suffering from X-linked disorders

Fermi Surface as the Driving Mechanism for Helical Antiferromagnetic Ordering in Gd-Y Alloys

The first direct experimental evidence for the Fermi surface (FS) driving the helical antiferromagnetic ordering in a gadolinium-yttrium alloy is reported. The presence of a FS sheet capable of nesting is revealed, and the nesting vector associated with the sheet is found to be in excellent agreement with the periodicity of the helical ordering.Comment: 4 pages, 4 figure

Feeding the Worlth Healthily: the Challenge of Measuring the effects of Agriculture on Health

Agricultural production, food systems and population health are intimately linked. While there is a strong evidence base to inform our knowledge of what constitutes a healthy human diet, we know little about actual food production or consumption in many populations and how developments in the food and agricultural system will affect dietary intake patterns and health. The paucity of information on food production and consumption is arguably most acute in low- and middle-income countries, where it is most urgently needed to monitor levels of under-nutrition, the health impacts of rapid dietary transition and the increasing ‘double burden’ of nutrition-related disease. Food availability statistics based on food commodity production data are currently widely used as a proxy measure of national-level food consumption, but using data from the UK and Mexico we highlight the potential pitfalls of this approach. Despite limited resources for data collection, better systems of measurement are possible. Important drivers to improve collection systems may include efforts to meet international development goals and partnership with the private sector. A clearer understanding of the links between the agriculture and food system and population health will ensure that health becomes a critical driver of agricultural change

Pledging to harm:A linguistic appraisal analysis of judgment comparing realized and non-realized violent fantasies

Intent is a psychological quality that threat assessors view as a required step on a threatener’s pathway to action. Recognizing the presence of intent in threatening language is therefore crucial to determining whether a threat is credible. Nevertheless, a ‘lack of empirical guidance’ (p. 326) is available concerning how violent intent is expressed linguistically. Using the subsystem of judgment in Appraisal analysis, this study compares realized with non-realized ‘pledges to harm’, revealing occasionally counterintuitive patterns of stancetaking by both author types – for example, that the non-realized texts are both prosodically more violent and more threatening, while the realized pledges are more ethically nuanced – which may begin to shed light on which attitudinal markers reliably correlate with an author’s intention to do future harm