Sorting and inequality in Canadian schools

Researchers and educators often argue that a student's peers strongly influence his or her educational outcomes. If so, an unequal distribution of advantaged and disadvantaged students across schools in a community will leave many students doubly disadvantaged and amplify existing inequalities. We explore the relationship between the degree of sorting by socioeconomic characteristics, ethnicity and language across schools within a community and inequality as measured by the variance of standardized high school exam scores within the community. Simple cross- sectional estimates suggest a direct relationship between sorting by ethnicity and the variance of test scores, but no direct relationship between sorting by income or primary parent's education and the variance of test scores. We then implement a fixed effects estimator to control for endogeneity in the extent of sorting: the results indicate that sorting by ethnicity does not affect the variance of test scores, but that sorting by home language and primary parent's education does.social interactions, peer effects, sorting, classroom effects

Sorting, Peers and Achievement of Aboriginal Students in British Columbia

We use administrative data on students in grades 4 and 7 in British Columbia to examine the extent to which differences in school environment contribute to the achievement gap between Aboriginal and non-Aboriginal students as measured by standardized test scores. We find that segregation of Aboriginal and non-Aboriginal students is substantial, and that differences in the distribution of these two groups across schools account for roughly half the overall achievement gap on the Foundation Skills Assessment tests in grade 7. The substantial school-level segregation of Aboriginal and non-Aboriginal student across schools means that Aboriginal students on average have a higher proportion of peers who are themselves Aboriginal, as well as a higher proportion of peers in special education. We estimate the effect of peer composition on value-added exam outcomes, using longitudinal data on multiple cohorts of students together with school-by-grade fixed effects to account for endogenous selection into schools. We find that having a greater proportion of Aboriginal peers, if anything, improves the achievement of Aboriginal students.Aboriginal education, peer effects

Post-fire successional response of Lepidoptera communities in the Sierra Madre Oriental mountain range

Anthropogenic forest fire accounted for 63% of fire activity in Cumbres de Monterrey National Park between 2000 and 2017. Changing forest fire regimes may have serious implications for forest health, impacting the local economy which depends heavily on ecosystem services in the park. Lepidoptera are important forest pollinators and are potentially useful indicators due to their sensitivity to ecological disturbances, therefore their response to disturbance merits study. The objectives of the current study were 1. to characterize changes in canopy openness, understory cover and flower diversity and 2. to characterize diurnal Lepidoptera communities in terms of species diversity, and proportions of specialist and generalist species in early post-fire succession. Forest structure and butterfly diversity were surveyed in an area recently affected by anthropogenic forest fire and an unburned control site. Four 200m transects were established in each site with two 2 × 2m plots on either end of each transect. Habitat assessments in these plots provided data on understory vegetation and canopy cover. Walkand-count transect surveys and Van Someren-Rydon traps were employed to measure Lepidoptera species richness and abundance. Canopy openness and understory cover were significantly lower in the control site (p<0.001). Rarefied species richness and diversity indices of butterfly communities measured by transect method were not significantly different, but the observed butterfly abundance (p=0.002) and species richness (p=0.005) per sampling day was significantly higher in the burned site throughout the year. Generalist species were significantly more abundant (p=0.037) in the burned site. The differences in forest structure post-fire reflect well-studied successional processes. Changes in butterfly community composition post-fire support the theory that butterflies are early colonizing species and are sensitive to forest disturbances. However, generalist species abundance tends to increase in open habitats while specialist species are more sensitive to disturbances. Specialists A. troglodyta and P. pilumnus are suggested as potential indicator species for this ecosystem RESUMEN Incendios forestales antropogénicos comprendieron el 63% de incendios en Parque Nacional Cumbres de Monterrey entre los años 2000 y 2017. Cambios en el régimen de incendios forestales podrían tener impactos importantes en la salud del bosque y la económica local, cual depende sobre los servicios ambientales del parque. Los lepidópteros son polinizadores importantes y podrían ser especies indicadores útiles por su sensibilidad a disturbios ecológicos y por lo tanto, su responsorio a disturbios merece estudio. Los objetivos de este estudio fueron 1. caracterizar cambios en la cobertura del dosel, cobertura del sotobosque y la diversidad de flores y 2. caracterizar comunidades diurnas de lepidópteros en cuanto diversidad y proporciones de especies generalistas y especialistas en la sucesión temprana post-incendio. Estructura forestal y diversidad de mariposas se muestrearon en un área recientemente afectada por un incendio antropogénico, y un área control no quemado. Cuatro transectos de 200m se establecieron en cada sitio con parcelas de 2 × 2m al inicio y el final de cada transecto. Muestreos de hábitat en estas parcelas proporcionaron datos sobre la cobertura del dosel y del sotobosque. Transectos caminar-y-contar y trampas Van Someren-Rydon se emplearon para muestrear la riqueza de especies y abundancia de Lepidópteros. La cobertura del dosel fue más alta, y la cobertura del sotobosque fue más bajo en el sitio control (p<0.001). Las diferencias entre riqueza de especies e índices de diversidad Shannon y Simpson enrarecidos medidos por el método transecto no fueron significativas, pero las diferencias entre la abundancia (p=0.002) y riqueza (p=0.005) de especies observadas por fecha fueron más altas en el lugar quemado. Especies generalistas fueron más abundantes en el sitio quemado (p=0.037). Las diferencias en la estructura del bosque post-incendio reflejan procesos de sucesión de bosque bien conocidos. Cambios en la comunidad de mariposas apoyan la teoría que las mariposas son especies de colonizadores tempranos y son sensibles a disturbios. Sin embargo, especies de generalistas tienden a incrementar en hábitats abiertos mientras especialistas son más sensibles a disturbios. Las especialistas A. troglodyta y P. pilumnus se sugieren como especies indicadores potenciales para este ecosistema

The James Clerk Maxwell telescope Legacy Survey of the Gould Belt: a molecular line study of the Ophiuchus molecular cloud

CO, 13CO, and C18O J = 3-2 observations are presented of the Ophiuchus molecular cloud. The 13CO and C18O emission is dominated by the Oph A clump, and the Oph B1, B2, C, E, F, and J regions. The optically thin(ner) C18O line is used as a column density tracer, from which the gravitational binding energy is estimated to be 4.5 × 1039 J (2282 M⊙ km2 s-2). The turbulent kinetic energy is 6.3 × 1038 J (320 M⊙ km2 s-2), or seven times less than this, and therefore the Oph cloud as a whole is gravitationally bound. 30 protostars were searched for high-velocity gas, with 8 showing outflows, and 20 more having evidence of high-velocity gas along their lines of sight. The total outflow kinetic energy is 1.3 × 1038 J (67 M⊙ km2 s-2), corresponding to 21 per cent of the cloud's turbulent kinetic energy. Although turbulent injection by outflows is significant, but does not appear to be the dominant source of turbulence in the cloud. 105 dense molecular clumplets were identified, which had radii ˜0.01-0.05 pc, virial masses ˜0.1-12 M⊙, luminosities ˜0.001-0.1 K km s-1 pc-2, and excitation temperatures ˜10-50 K. These are consistent with the standard Giant Molecular Cloud (GMC) based size-linewidth relationships, showing that the scaling laws extend down to size scales of hundredths of a parsec, and to subsolar-mass condensations. There is however no compelling evidence that the majority of clumplets are undergoing free-fall collapse, nor that they are pressure confined

Pictorial gaze cues do not enhance long tailed macaques’ performance on a computerised object location task

The perception of pictorial gaze cues was examined in long-tailed macaques (Macaca fascicularis). A computerised object location task was used to explore whether the monkeys would show faster response time to locate a target when its appearance was preceded with congruent as opposed to incongruent gaze cues. Despite existing evidence that macaques preferentially attend to the eyes in facial images and also visually orient with depicted gaze cues, the monkeys did not show faster response times on congruent trials either in response to schematic or photographic stimuli. These findings coincide with those reported for baboons tested with a similar paradigm in which gaze cues preceded a target identification task (Fagot and Deruelle 2002). When tested with either pictorial stimuli or interactants, non human primates readily follow gaze but do not seem to use this mechanism to identify a target object; there seems to be some mismatch in performance between attentional changes and manual responses to gaze cues on ostensibly similar tasks

Cross-National Differences in Victimization : Disentangling the Impact of Composition and Context

Varying rates of criminal victimization across countries are assumed to be the outcome of countrylevel structural constraints that determine the supply ofmotivated o¡enders, as well as the differential composition within countries of suitable targets and capable guardianship. However, previous empirical tests of these ‘compositional’ and ‘contextual’ explanations of cross-national di¡erences have been performed upon macro-level crime data due to the unavailability of comparable individual-level data across countries. This limitation has had two important consequences for cross-national crime research. First, micro-/meso-level mechanisms underlying cross-national differences cannot be truly inferred from macro-level data. Secondly, the e¡ects of contextual measures (e.g. income inequality) on crime are uncontrolled for compositional heterogeneity. In this paper, these limitations are overcome by analysing individual-level victimization data across 18 countries from the International CrimeVictims Survey. Results from multi-level analyses on theft and violent victimization indicate that the national level of income inequality is positively related to risk, independent of compositional (i.e. micro- and meso-level) di¡erences. Furthermore, crossnational variation in victimization rates is not only shaped by di¡erences in national context, but also by varying composition. More speci¢cally, countries had higher crime rates the more they consisted of urban residents and regions with lowaverage social cohesion.

The JCMT BISTRO Survey: Studying the Complex Magnetic Field of L43

We present observations of polarized dust emission at 850 μm from the L43 molecular cloud, which sits in the Ophiuchus cloud complex. The data were taken using SCUBA-2/POL-2 on the James Clerk Maxwell Telescope as a part of the BISTRO large program. L43 is a dense (NH 10 22 2 ~ –1023 cm−2) complex molecular cloud with a submillimeter-bright starless core and two protostellar sources. There appears to be an evolutionary gradient along the isolated filament that L43 is embedded within, with the most evolved source closest to the Sco OB2 association. One of the protostars drives a CO outflow that has created a cavity to the southeast. We see a magnetic field that appears to be aligned with the cavity walls of the outflow, suggesting interaction with the outflow. We also find a magnetic field strength of up to ∼160 ± 30 μG in the main starless core and up to ∼90 ± 40 μG in the more diffuse, extended region. These field strengths give magnetically super- and subcritical values, respectively, and both are found to be roughly trans-Alfvénic. We also present a new method of data reduction for these denser but fainter objects like starless cores

Magnetic Fields toward Ophiuchus-B Derived from SCUBA-2 Polarization Measurements

We present the results of dust emission polarization measurements of Ophiuchus-B (Oph-B) carried out using the Submillimetre Common-User Bolometer Array 2 (SCUBA-2) camera with its associated polarimeter (POL-2) on the James Clerk Maxwell Telescope in Hawaii. This work is part of the B-fields in Star-forming Region Observations survey initiated to understand the role of magnetic fields in star formation for nearby star-forming molecular clouds. We present a first look at the geometry and strength of magnetic fields in Oph-B. The field geometry is traced over ~0.2 pc, with clear detection of both of the sub-clumps of Oph-B. The field pattern appears significantly disordered in sub-clump Oph-B1. The field geometry in Oph-B2 is more ordered, with a tendency to be along the major axis of the clump, parallel to the filamentary structure within which it lies. The degree of polarization decreases systematically toward the dense core material in the two sub-clumps. The field lines in the lower density material along the periphery are smoothly joined to the large-scale magnetic fields probed by NIR polarization observations. We estimated a magnetic field strength of 630 ± 410 μG in the Oph-B2 sub-clump using a Davis–Chandrasekhar–Fermi analysis. With this magnetic field strength, we find a mass-to-flux ratio λ = 1.6 ± 1.1, which suggests that the Oph-B2 clump is slightly magnetically supercritical