Reversible gelation and dynamical arrest of dipolar colloids

We use molecular dynamics simulations of a simple model to show that dispersions of slightly elongated colloidal particles with long-range dipolar interactions, like ferrofluids, can form a physical (reversible) gel at low volume fractions. On cooling, the particles first self-assemble into a transient percolating network of cross-linked chains, which, at much lower temperatures, then undergoes a kinetic transition to a dynamically arrested state with broken ergodicity. This transition from a transient to a frozen gel is characterised by dynamical signatures reminiscent of jamming in much denser dispersions.Comment: 6 pages, 7 figure

Dubious decision evidence and criterion flexibility in recognition memory.

When old-new recognition judgments must be based on ambiguous memory evidence, a proper criterion for responding "old" can substantially improve accuracy, but participants are typically suboptimal in their placement of decision criteria. Various accounts of suboptimal criterion placement have been proposed. The most parsimonious, however, is that subjects simply over-rely on memory evidence - however faulty - as a basis for decisions. We tested this account with a novel recognition paradigm in which old-new discrimination was minimal and critical errors were avoided by adopting highly liberal or conservative biases. In Experiment 1, criterion shifts were necessary to adapt to changing target probabilities or, in a "security patrol" scenario, to avoid either letting dangerous people go free (misses) or harming innocent people (false alarms). Experiment 2 added a condition in which financial incentives drove criterion shifts. Critical errors were frequent, similar across sources of motivation, and only moderately reduced by feedback. In Experiment 3, critical errors were only modestly reduced in a version of the security patrol with no study phase. These findings indicate that participants use even transparently non-probative information as an alternative to heavy reliance on a decision rule, a strategy that precludes optimal criterion placement

Integration of Oscillatory and Subanalytic Functions

We prove the stability under integration and under Fourier transform of a concrete class of functions containing all globally subanalytic functions and their complex exponentials. This paper extends the investigation started in [J.-M. Lion, J.-P. Rolin: "Volumes, feuilles de Rolle de feuilletages analytiques et th\'eor\`eme de Wilkie" Ann. Fac. Sci. Toulouse Math. (6) 7 (1998), no. 1, 93-112] and [R. Cluckers, D. J. Miller: "Stability under integration of sums of products of real globally subanalytic functions and their logarithms" Duke Math. J. 156 (2011), no. 2, 311-348] to an enriched framework including oscillatory functions. It provides a new example of fruitful interaction between analysis and singularity theory.Comment: Final version. Accepted for publication in Duke Math. Journal. Changes in proofs: from Section 6 to the end, we now use the theory of continuously uniformly distributed modulo 1 functions that provides a uniform technical point of view in the proofs of limit statement

Gravitational Lensing and the Hubble Deep Field

We calculate the expected number of multiply-imaged galaxies in the Hubble Deep Field (HDF), using photometric redshift information for galaxies with m_I < 27 that were detected in all four HDF passbands. A comparison of these expectations with the observed number of strongly lensed galaxies constrains the current value of Omega_m-Omega_Lambda, where Omega_m is the mean mass density of the universe and Omega_Lambda is the normalized cosmological constant. Based on current estimates of the HDF luminosity function and associated uncertainties in individual parameters, our 95% confidence lower limit on Omega_m-Omega_Lambda ranges between -0.44, if there are no strongly lensed galaxies in the HDF, and -0.73, if there are two strongly lensed galaxies in the HDF. If the only lensed galaxy in the HDF is the one presently viable candidate, then, in a flat universe (Omega_m+Omega_Lambda=1), Omega_Lambda < 0.79 (95% C.L.). These limits are compatible with estimates based on high-redshift supernovae and with previous limits based on gravitational lensing.Comment: 4 pages (aipproc.sty), 2 figures. To appear in "After the dark ages: when galaxies were young," proceedings of the 9th Annual October Astrophysics Conference, eds. S. S. Holt & E. P. Smit

Is the growth of the child of a smoking mother influenced by the father's prenatal exposure to tobacco? A hypothesis generating longitudinal study

OBJECTIVES: Transgenerational effects of different environmental exposures are of major interest, with rodent experiments focusing on epigenetic mechanisms. Previously, we have shown that if the study mother is a non-smoker, there is increased mean birth weight, length and body mass index (BMI) in her sons if she herself had been exposed prenatally to her mother's smoking. The aim of this study was to determine whether the prenatal smoke exposure of either parent influenced the growth of the fetus of a smoking woman, and whether any effects were dependent on the fetal sex. DESIGN: Population-based prebirth cohort study. SETTING: Avon Longitudinal Study of Parents and Children. PARTICIPANTS: Participants were residents of a geographic area with expected date of delivery between April 1991 and December 1992. Among pregnancies of mothers who smoked during pregnancy, data were available concerning maternal and paternal prenatal exposures to their own mother smoking for 3502 and 2354, respectively. PRIMARY AND SECONDARY OUTCOME MEASURES: Birth weight, length, BMI and head circumference. RESULTS: After controlling for confounders, there were no associations with birth weight, length or BMI. There was a strong adjusted association of birth head circumference among boys whose fathers had been exposed prenatally (mean difference −0.35 cm; 95% CI −0.57 to −0.14; p=0.001). There was no such association with girls (interaction p=0.006). Similar associations were found when primiparae and multiparae were analysed separately. In order to determine whether this was reflected in child development, we examined the relationships with IQ; we found that the boys born to exposed fathers had lower IQ scores on average, and that this was particularly due to the verbal component (mean difference in verbal IQ −3.65 points; 95% CI −6.60 to −0.70). CONCLUSIONS: Head size differences concerning paternal fetal exposure to smoking were unexpected and, as such, should be regarded as hypothesis generating

An exploratory study of the effectiveness of the structural arithmetic program at the second grade level.

Thesis (Ed.M.)--Boston Universit

The seasonal and spatial dynamics in the phytomacrofaunal communities of Lake Henley, Mastert : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Science in Ecology at Massey Universityon

Spatial and seasonal dynamics of macrophyte beds in Lake Henley, a shallow artificial lake in Masterton, were examined between June 1993 and June 1994. Observed fluctuations in macrophyte biomass were linked with changes in filamentous algae associated with the weed beds. Invertebrate communities associated with submerged macrophytes were also examined at multiple sites between June 1993 and June 1994. Overall community composition was related more to seasonal influences than differences between sites within the lake. However, species richness and abundance did differ spatially. Recommendations for the ongoing management of Lake Henley, including management of the macrophyte beds and the maintenance of water quality and quantity, are made with respect to the ecological characteristics of the lake. The influence of trophic status on macrophyte invertebrate communities was also explored with a survey conducted in May 1994 of 13 other lakes in the North Island. Nutrient enriched lakes were characterised by phytomacrofaunal communities with high abundance and higher numerical dominance, whereas nutrient poor lake phytomacrofaunal communities were characterised by lower abundances but higher diversity of some taxonomic groups, particularly insects

Children Tell Landscape-Lore among Perceptions of Place: Relating Ecocultural Digital Stories in a Conscientizing/Decolonizing Exploration

We know that when children feel a sense-of-relation within local natural environments, they are more prone to feel concern for them, while nurturing well-being and resilience in themselves and in lands/waters they inhabit. Positive environmental behaviors often follow into adulthood. Our human capacities for creating sustainable solutions in response to growing repercussions of global warming and climate change may grow if more children feel a sense of belonging in the wild natural world. As educators, if we listen to and learn from students’ voices about how they engage in nature, we can create pedagogical experiences directly relevant to their lives. Activities that relate to learners’ lives inspire motivation, curiosity, and furthers understanding. Behaviors supporting environmental stewardship, environmental justice, and participation in citizen science and phenology are more probable when children feel concern for ecological landscapes. Internationally, some educators are free to encourage a sense-of -relation by bringing students into natural places. Yet, there are many educators who are constrained from doing so by strict local, state, and national education policies and accountability measures. Overcoming restrictions requires creative, relevant, and enjoyable learner-centered opportunities. Research shows that virtual nature experiences can provide for beneficial connections with(in) nature for children and adults. It is best to bring children outside. When this is not possible, a sense of wonder may be encouraged in the classroom. Our exploratory collaborative digital landscape-lore project makes this possible. We expand awareness about how we, educators, and children alike, are engaged within the landscapes and waterscapes significant to us. The term landscape-lore articulates the primacy of the places we find meaningful. Our intercultural investigations took place in collaborative public schools in colonized landscapes. New Hampshire and New Zealand, known by their first inhabitants, the Aln8bak and Māori peoples respectively, as N’dakinna (the Dawnland) and Aotearoa (Land of the Long White Cloud) are landscapes that have transformed over millennia, as all places do. The deep relational knowing and caring for these landscapes and waterscapes for millennia has been greatly interrupted by colonization across the globe. Telling stories to following generations is serious storywork; they sustain culture, lands, and waters in reciprocity and deep memory. Landscape-lore and ecocultural multiliteracies, such as singing, oratory, music and dance are responsible rituals that support ancestral Indigenous Environmental Knowing and Wisdom Systems. These cultural frameworks could be vital for encouraging respectful and collaborative sustainability solutions for the entire biosphere. Centered within critical Indigenous methodologies, this relational, qualitative study endeavored to be ecoculturally responsive, respectful, and culturally sustaining. Creating experiential digital landscape lore gave us ways to share the natural world in our own voices. We were situated within a shared sense of holistic belonging in ecocultural places and communities. Exchanging our independent excursions in local land-/ waterscapes by crossing virtual biogeographical borders increased exposure to diverse worldviews and places. As a transdisciplinary process, such a learning experience fosters new emotional connections and critical human-nature systems thinking. Our study incorporates children’s landscape-lore in an ethical and respectful manner. Our main research questions were: 1. How are children engaged with(in) the natural world as described in their digital landscape-lore? 2. What culturally responsive background knowledges are vital for educators preparing to facilitate such a learning project both locally and globally? 3. How might a digital landscape-lore project support goals for connecting children and communities in relational reciprocity within and across diverse landscapes, worldviews, and times? How might landscape-lore create personal relevance, curiosity, and learning? Findings demonstrate that co-researching children each have experiential environmental knowledge that informs their relationships within their ecocultural locations and landscape-lore. Their embodied movements and experiences in nature are also significant. Children’s landscape-lore describe social participation in exploratory adventures among friends, family, beyond-human kin. Interactions with biophysical entities within land- and waterscapes hold diverse worldview meanings for children. Children demonstrated that they are savvy, digital citizens. They educated teachers and classmates about places meaningful to them. Significantly, most landscape-lore, in both N’dakinna/New Hampshire and Aotearoa New Zealand, included social moments with friends and family, and described local animals. This contrasts with many studies demonstrating a preference for distant charismatic wildlife. Children’s experiential landscape lore stories described the local biodiversity in their home environments. Our collaborative experiential landscape-lore supported innovative tech skills and critical multiliteracies directly relevant to the interests and ecocultural lives of learners of all ages