Do tasks make a difference? Accounting for heterogeneity of performance of children with reading difficulties on tasks of executive function : findings from a meta-analysis

Research studies have implicated executive functions in reading difficulties (RD). But while some studies have found children with RD to be impaired on tasks of executive function other studies report unimpaired performance. A meta-analysis was carried out to determine whether these discrepant findings can be accounted for by differences in the tasks of executive function that are utilized. A total of 48 studies comparing the performance on tasks of executive function of children with RD with their typically developing peers were included in the meta-analysis, yielding 180 effect sizes. An overall effect size of 0.57 (SE .03) was obtained, indicating that children with RD have impairments on tasks of executive function. However, effect sizes varied considerably suggesting that the impairment is not uniform. Moderator analysis revealed that task modality and IQ-achievement discrepancy definitions of RD influenced the magnitude of effect; however, the age and gender of participants and the nature of the RD did not have an influence. While the children's RD were associated with executive function impairments, variation in effect size is a product of the assessment task employed, underlying task demands, and definitional criteria

Inner mean-motion resonances with eccentric planets: A possible origin for exozodiacal dust clouds

High levels of dust have been detected in the immediate vicinity of many stars, both young and old. A promising scenario to explain the presence of this short-lived dust is that these analogues to the Zodiacal cloud (or exozodis) are refilled in situ through cometary activity and sublimation. As the reservoir of comets is not expected to be replenished, the presence of these exozodis in old systems has yet to be adequately explained. It was recently suggested that mean-motion resonances (MMR) with exterior planets on moderately eccentric ($\mathrm{e_p}\gtrsim 0.1$) orbits could scatter planetesimals on to cometary orbits with delays of the order of several 100 Myr. Theoretically, this mechanism is also expected to sustain continuous production of active comets once it has started, potentially over Gyr-timescales. We aim here to investigate the ability of this mechanism to generate scattering on to cometary orbits compatible with the production of an exozodi on long timescales. We combine analytical predictions and complementary numerical N-body simulations to study its characteristics. We show, using order of magnitude estimates, that via this mechanism, low mass discs comparable to the Kuiper Belt could sustain comet scattering at rates compatible with the presence of the exozodis which are detected around Solar-type stars, and on Gyr timescales. We also find that the levels of dust detected around Vega could be sustained via our proposed mechanism if an eccentric Jupiter-like planet were present exterior to the system's cold debris disc.Comment: 15 pages, 12 figures; Accepted for publication in MNRA

New Farmer Jump Start Project

Southwest Iowa development groups looked at several ways to entice new farmers to commit to local food production

The Politics of Disciplinary Advantage

Interdisciplinary work avoids specialisation's growing fragmentation, but it also loses the political advantage of setting criteria and patrolling boundaries. Research that faces the challenge of bringing together concepts from several areas (e.g. in deep ecology, health studies, and natural resource management) is often criticised for blurring distinctions, for being unscientific, and for being conceptually trite. In addition, disciplinary work produces advantages for its practitioners which those who attempt more open approaches rarely enjoy. Besides epistemic authority and public legitimacy, such advantages include a degree of control over resources, clearer standards for publishing, and a critical mass of disciplined members who protect the turf of their specialisation. How can interdisciplinary work in future best play the political game? Should interdisciplinary scholars be between the boundaries of other areas, exhorting those protected within to choose relevance and come out and do as we do? Do we need boundaries for interdisciplinary work, carefully and vigorously controlled, so that we too can form distinctions based on criteria for methodological rigour? Is there a place for full theoretical awareness of what distinguishes interdisciplinary work? If interdisciplinarity is to mobilise support, does it need, just like any discipline, its own self-regulating guild

Intimate Collisions: Identity, Community, and Place in the Kansas Dirt-Track Auto Racing Sphere

Dirt-track auto racing, spread across the U.S. and concentrated in the nation’s Heartland, is largely unexplored territory within the cultural studies field. In turn, this project addresses contemporary Kansas-centered auto racing as a cultural sphere composed of spaces, objects, and practices derived from the “action” on the dirt oval. Participant-observation ethnography comprised the bulk of research, conducted over three years in garages, museums, and other spaces in which racing-related practice took place. Research and analysis were driven by an identity-based inquiry: How do participants construct senses of self in relation to the Kansas dirt-track racing community? On one hand, I trace processes of reproduction within the racing sphere. Identity ideologies and organizations have long reflected male dominance of competitive spaces, as well as the ubiquity of Whiteness among participants in general. Gendered organization appeared to result, in part, from the patrilineal routes through which men socialized boys into mechanical and operational familiarity with race cars. As a result, locally hegemonic masculinity was constructed around automotive-mechanical competency, competitiveness, and “rugged” engagement with speed and objects that threaten bodily harm. On the other hand, I address the ways in which racing practice entails reformulations of dominant cultural structures. When articulating the appeal of dirt-track racing, participants emphasized variety and disruption, especially in regards to “exciting” on-track “action,” which was contrasted against the mass culture of corporatized NASCAR. Furthermore, drivers embraced the opportunity to enact industrial productivity through their small-group racing operations; in doing so, they exercised power and sovereignty not typically present in their predominantly working-class occupations. As a whole, contextualized within a culturally shifting Kansas, participants converged within the racing sphere to find a sense of localistic community, thus engaging in “intimate collisions” both on and around the track

Science-Based Policy Plan for Australia\u27s Coral Reefs

Australia’s coral reefs are currently under threat from a range of short-­‐ and long-­‐term stressors. The ability of corals to recover from acute disturbance events, such as bleaching, cyclones and crown-­of-thorns seastars outbreaks, is greatly influenced by the multitude of stressors reefs are currently experiencing (1). Since healthy coral habitat is essential for the persistence of associated fish and invertebrate communities, as well as the industries that rely on them (2), all possible action must be taken to reduce stress factors to corals and associated organisms. Practical changes to current reef policies will reverse the decline in the health of Australia’s coral reefs and increase the viability of all of the reef’s associated industries

Modal phase modulators based on liquid crystals with 3D-printed polymer microstructures: increasing size and complexity

We present extended capabilities in simple liquid crystal-based devices that are applicable to adaptive optics and other related fields requiring wavefront manipulation. The laser-written devices can provide complex phase profiles, but are extremely simple to operate, requiring only a single electrode pair tuned between 0 and 10 V RMS. Furthermore, the devices operate in the transmissive mode for easy integration into the optical path. We present here as examples three such devices: the first device reproduces the defocus Zernike polynomial; the second device reproduces a seventh-order Zernike polynomial, tertiary coma; and the last example is of a primary spherical aberration. All devices offer wavelength-scale wavefront manipulation up to more than 2π radians peak-to-peak phase at a wavelength of 660 nm. The coma correction device is significantly more complex, reproducing a mode two orders higher than previous demonstrations, while the spherical device is nearly a full order of magnitude larger, measuring 2 mm in diameter

Late Holocene Lake-level Variation in Southeastern Lake Superior: Tahquamenon Bay, Michigan

Internal architecture and ages of 71 beach ridges in the Tahquamenon Bay embayment along the southeastern shore of Lake Superior on the Upper Peninsula of Michigan were studied to generate a late Holocene relative lake-level curve. Establishing a long-term framework is important to examine the context of historic events and help predict potential future changes critical for effective water resource management. Ridges in the embayment formed between about 4,200 and 2,100 calendar years before 1950 (cal. yrs. B.P.) and were created and preserved every 28 ± 4.8 years on average. Groups of three to six beach ridges coupled with inflections in the lake-level curve indicate a history of lake levels fluctuations and outlet changes. A rapid lake-level drop (approximately 4 m) from about 4,100 to 3,800 cal. yrs. B.P. was associated with a fall from the Nipissing II high-water-level phase. A change from a gradual fall to a slight rise was associated with an outlet change from Port Huron, Michigan/Sarnia, Ontario to Sault Ste. Marie, Michigan/Ontario. A complete outlet change occurred after the Algoma high-water-level phase (ca. 2,400 cal. yrs. B.P.). Preliminary rates of vertical ground movement calculated from the strandplain are much greater than rates calculated from historical and geologic data. High rates of vertical ground movement could have caused tectonism in the Whitefish Bay area, modifying the strandplain during the past 2,400 years. A tectonic event at or near the Sault outlet also may have been a factor in the outlet change from Port Huron/Sarnia to Sault Ste. Marie