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Density-dependent competition for food influences the foraging behaviour and demography of colonial animals, but how this influence varies across a species’ latitudinal range is poorly understood. Here we used satellite tracking from 21 Northern Gannet Morus bassanus colonies (39% of colonies worldwide, supporting 73% of the global population) during chick-rearing to test how foraging trip characteristics (distance and duration) covary with colony size (138–60 953 breeding pairs) and latitude across 89% of their latitudinal range (46.81–71.23° N). Tracking data for 1118 individuals showed that foraging trip duration and maximum distance both increased with square-root colony size. Foraging effort also varied between years for the same colony, consistent with a link to environmental variability. Trip duration and maximum distance also decreased with latitude, after controlling for colony size. Our results are consistent with density-dependent reduction in prey availability influencing colony size and reveal reduced competition at the poleward range margin. This provides a mechanism for rapid population growth at northern colonies and, therefore, a poleward shift in response to environmental change. Further work is required to understand when and how colonial animals deplete nearby prey, along with the positive and negative effects of social foraging behaviour.

The value of articles published in journals devoted to the scholarship of teaching and learning constitutes a relatively unexplored topic of inquiry within the broader field of inquiry on the scholarship of teaching and learning. This article addresses this topic using citations and four types of altmetrics as indicators of value. We used a sample of 100 articles published in four SOTL focused journals: two high consensus journals ("BioScience: Journal of College Biology Teaching" and "The Journal of Chemical Education") and two low consensus journals ("Teaching History" and "Teaching Sociology"). In addition to the level of consensus of the discipline of these journals, we also measured the institutional type of the first authors of these articles and the type of study of the article. We advanced three conclusions from our data analysis with the first one being of particular significance to SOTL work. This conclusion is that the pattern of findings of this study cry out fairly loudly that articles published in SOTL-focused journals hold value to users of the articles as expressed through citations of them, as well as mentions of them through various altmetrics. Moreover the similar magnitudes of this value transpires regardless of the institutional type of the article's first author and whether the article recommended a practice or recommended content. However, the value ascribed to articles differ according to the level of consensus of the field of the SOTL journal, which show a difference in article views, Twitter mentions and Mendeley uses.

Early Intensive Behavioural Intervention (EIBI) is effective for preschoolers with autism spectrum disorder (ASD). Parental measures are rarely included in EIBI effectiveness studies, yet parental distress and lower self-efficacy are associated with poorer child outcomes. Parents of preschoolers with ASD (N = 485) were surveyed at baseline (T1), one-year post-intervention (T2), and school entry (T3) about family distress/crisis, parental self-efficacy, and satisfaction with services in two Canadian provinces. Family distress/crisis decreased and parental self-efficacy increased from T1 to T2. Increases in self-efficacy were largely maintained at T3. Parents were highly satisfied with services. Greater satisfaction for those residing in the province utilizing a parent-coaching model suggests that parent involvement is associated with positive parent outcomes.

An artificial neural network was developed to augment the accuracy of a physically based computer model in relating heat discharge to visible plume volume of a 12-cell mechanical draft cooling tower. In a previous study, Savannah River National Laboratory developed a 1D model to capture the average power plant discharge levels via analysis of a series of visual images but was unable to accurately predict individual cases, resulting in an overall average error of about 5%, but individual comparisons resulted in an R2 of 0.36. Three optimization algorithms were applied to better fit the entrainment coefficients, and the artificial neural network model was applied to 289 cases of a 12-cell mechanical draft cooling tower power generation facility. Two artificial neural networks configurations consisted of 10 and 47 nodes that used as input readily available plant data, observed cooling tower plume conditions, observed operational conditions, local and regional weather, and the predicted plume volume from the physical model; the individual predictions’ accuracy improved to R2>0.95. This article concludes the sensitivities for the 1D model and additional actions to progress this field of study as well as applications for cooling tower monitoring. This strategy demonstrated an encouraging first step towards using multi-modal artificial neural network machine learning technology for information fusion to estimate power levels from external observations.

Species interactions exhibit varying degrees of specialization, ranging from generalist to specialist interactions. For many interactions (e.g., plant-microbiome) we lack standardized metrics of specialization, hindering our ability to apply comparative frameworks of specificity across niche axes and organismal groups. Here, we discuss the concept of plant host specificity of arbuscular mycorrhizal (AM) fungi and ectomycorrhizal (EM) fungi, including the predominant theories for their interactions: Passenger, Driver, and Habitat Hypotheses. We focus on five major areas of interest in advancing the field of plant-mycorrhizal fungal host specificity: phylogenetic specificity, host physiology specificity, functional specificity, habitat specificity, and mycorrhizal fungal-mediated plant rarity. Considering the need to elucidate foundational concepts of specificity in this globally important symbiosis, we propose standardized metrics and comparative studies to enhance our understanding. We also emphasize the importance of analyzing global mycorrhizal data holistically to draw meaningful conclusions and suggest a shift toward single-species analyses to unravel the complexities underlying these associations.

Background: A significant limitation of femoral artery access for cardiac interventions is the increased risk of vascular complications and bleeding compared to radial access. Ultrasound (US)-guided femoral access may reduce major vascular complications and bleeding. We aim to determine whether routinely using US guidance for femoral arterial access for coronary angiography or intervention will reduce Bleeding Academic Research Consortium (BARC) 2, 3, or 5 bleeding or major vascular complications. Methods: The Ultrasound Guidance for Vascular Access for Cardiac Procedures: A Randomized Trial (UNIVERSAL) is a multicentre, prospective, open-label, randomized trial with blinded outcomes assessment. Patients undergoing coronary angiography with or without intervention via a femoral approach with fluoroscopic guidance will be randomized 1:1 to US-guided femoral access, compared to no US. The primary outcome is the composite of major bleeding based on the BARC 2, 3, or 5 criteria or major vascular complications within 30 days. The trial is designed to have 80% power and a 2-sided alpha level of 5% to detect a 50% relative risk reduction for the primary outcome based on a control event rate of 14%. Results: We completed enrollment on April 29, 2022, with 621 randomized patients. The patients had a mean age of 71 years (25.4% female), with a high rate of comorbidities, as follows: 45% had a prior percutaneous coronary intervention; 57% had previous coronary artery bypass surgery; and 18% had peripheral vascular disease. Conclusions: The UNIVERSAL trial will be one of the largest randomized trials of US-guided femoral access and has the potential to change guidelines and increase US uptake for coronary procedures worldwide. Résumé: Introduction: Par rapport à l’abord radial, la limitation importante de l’abord artériel fémoral lors des interventions au cœur pose un risque accru de complications vasculaires et de saignements. L’abord fémoral guidé par ultrasons (US) peut contribuer à réduire les complications vasculaires majeures et les saignements. Nous avons pour objectif de déterminer si l’utilisation systématique du guidage par US pour l’abord artériel fémoral lors des angiographies ou des interventions coronariennes contribuera à réduire les saignements de type 2, 3 ou 5 selon le Bleeding Academic Research Consortium (BARC) ou les complications vasculaires majeures. Méthodes: L’Ultrasound Guidance for Vascular Access for Cardiac Procedures: A Randomized Trial (UNIVERSAL) est un essai multicentrique, prospectif, ouvert, à répartition aléatoire, réalisé par une évaluation à l’insu des résultats. Les patients subissant une angiographie coronarienne avec ou sans intervention par voie fémorale sous guidage fluoroscopique seront répartis de façon aléatoire 1:1 à l’abord fémoral guidé par US ou sans US. Le principal critère d’évaluation est le critère composite de saignements majeurs de type 2, 3 ou 5 selon les critères du BARC ou de complications vasculaires majeures dans les 30 jours. L’essai est conçu de façon à avoir une puissance de 80 % et un seuil alpha bilatéral de 5 % pour déterminer la réduction du risque relatif de 50 % du critère d’évaluation principal selon un taux d’événements dans le groupe témoin de 14 %. Résultats: Le 29 avril 2022, nous avons terminé le recrutement de 621 patients choisis aléatoirement. Les patients avaient un âge moyen de 71 ans (25,4 % de femmes) et un taux élevé de comorbidités : 45 % avaient déjà subi une intervention coronarienne percutanée, 57 % avaient déjà subi un pontage aorto-coronarien et 18 % avaient une maladie vasculaire périphérique. Conclusions: L’essai UNIVERSAL qui sera l’un des plus vastes essais à répartition aléatoire sur l’abord fémoral guidé par US a le potentiel de faire changer les lignes directrices et de faire augmenter le recours aux US lors des interventions coronariennes dans le monde entier.

The eastern population of harlequin duck Histrionicus histrionicus in Canada has been designated a species of special concern since 2001 and as endangered from 1991 to 2001, largely due to low and declining wintering numbers detected in the 1980s. Our objectives were to summarize the current state of knowledge of harlequin duck abundance and distribution in Eastern Canada, and assess trends in wintering abundance across regions over the past 30+ years. Abundance estimates were generated from targeted surveys with thorough spatial coverage of major wintering areas on insular Newfoundland (NL), Nova Scotia (NS), and New Brunswick (NB) between 2015 and 2018, complemented by regional trends estimated from Christmas Bird Count (CBC) data collected at 12 sites across the same wintering range between 1988 and 2021. Overall, targeted surveys indicated that numbers have increased and distributions have expanded beyond historically surveyed regions, particularly in NS. This was supported by trends from CBC data, with steep average increases (mean λ > 1.05) on most CBC circles in Eastern Canada since 1988 or later. Using localized annual rates of mean population change from CBC data to project counts from dedicated surveys, we suggest wintering areas in the provinces of NL, NS, and NB may currently be supporting a combined total of 5682 birds (95% CI 5065-6354) in 2022, well exceeding the recovery target of 3000 individuals listed in the 2007 management plan. Our findings indicate that the eastern population is in recovery, but also emphasize that a consistent, dedicated monitoring program would enable managers to confidently evaluate management actions, and to respond most effectively should regional trends slow or reverse.

Abstract Anthropogenic food subsidies attract opportunistic generalists like gulls in high densities, which may lead to negative impacts on human communities and local ecosystems. Managing impacts requires understanding why gulls use particular natural or industrial sites at different times of day or phases of the breeding cycle. Use of natural and human‐influenced habitats likely varies temporally as gulls alter schedules and site selection to match the predictability of different resources as they vary through space and time relative to patterns in human activities (seasonal industries, the work week, working hours) and natural rhythms (daylight, tide cycles), while gull resource requirements and restrictions to movement also shift with changing reproductive demands. We quantified seasonal and circadian patterns in American herring gull (Larus smithsoniansus) interactions with anthropogenic and natural sites throughout breeding using GPS data from 15 gulls tracked over 3 years from two colonies. We examined the weekly probability of gull occurrence at distinct destinations (e.g. breeding colony, islands, offshore, fish processing plants), and how occurrence varied with time of day, weekday/weekend, tide phase and colony, using GLMMs with a binomial response for destination‐specific occurrence. Probability at the colony varied predictably through the breeding season (highest attendance from dusk to dawn, during incubation and early chick rearing), providing confidence in the modelling approach for detecting temporal patterns in behaviour. Gulls visited other islands mostly outside incubation and early chick rearing, and from dusk through the night, likely roosting. Occurrence offshore where interaction with fishing vessels is possible was highest from dusk to dawn, and differed among colonies, but was the most likely destination during incubation and early chick rearing. Occurrence at fish plants gradually increased until after fledging when attendance was highest from Aug‐Oct coincident with the peak of Atlantic herring (Clupea harengus) processing and was more likely during the weekdays, during working hours, and during low and flood tide. Gulls in southwest Nova Scotia, Canada, have the behavioural flexibility to adapt to both natural rhythms and human schedules when beneficial, enabling them to thrive in a region where industry and natural resources are abundant. These findings can provide information to guide when and where to test different subsidy management strategies locally, while also considering potential increased pressures on island ecosystems. We emphasise that management outcomes of reductions of food subsidies for opportunistic species depend on multiple factors, including availability of alternative food sources and timing of use.

Background Mineralocorticoid receptor antagonists have been shown to reduce mortality in patients after myocardial infarction with congestive heart failure. Whether routine use of spironolactone is beneficial after myocardial infarction is uncertain. Methods In this multicenter trial with a 2-by-2 factorial design, we randomly assigned patients with myocardial infarction who had undergone percutaneous coronary intervention to receive either spironolactone or placebo and either colchicine or placebo. The results of the spironolactone trial are reported here. The two primary outcomes were a composite of death from cardiovascular causes or new or worsening heart failure, evaluated as the total number of events; and a composite of the first occurrence of myocardial infarction, stroke, new or worsening heart failure, or death from cardiovascular causes. Safety was also assessed. Results We enrolled 7062 patients at 104 centers in 14 countries; 3537 patients were assigned to receive spironolactone and 3525 to receive placebo. At the time of our analyses, the vital status was unknown for 45 patients (0.6%). For the first primary outcome, there were 183 events (1.7 per 100 patient-years) in the spironolactone group as compared with 220 events (2.1 per 100 patient-years) in the placebo group over a median follow-up period of 3 years (hazard ratio adjusted for competing risk of death from noncardiovascular causes, 0.91; 95% confidence interval [CI], 0.69 to 1.21; P=0.51). With respect to the second primary outcome, an event occurred in 280 of 3537 patients (7.9%) in the spironolactone group and 294 of 3525 patients (8.3%) in the placebo group (hazard ratio adjusted for competing risk, 0.96; 95% CI, 0.81 to 1.13; P=0.60). Serious adverse events were reported in 255 patients (7.2%) in the spironolactone group and 241 (6.8%) in the placebo group. Conclusions Among patients with myocardial infarction, spironolactone did not reduce the incidence of death from cardiovascular causes or new or worsening heart failure or the incidence of a composite of death from cardiovascular causes, myocardial infarction, stroke, or new or worsening heart failure. [ABSTRACT FROM AUTHOR]

Background Inflammation is associated with adverse cardiovascular events. Data from recent trials suggest that colchicine reduces the risk of cardiovascular events. Methods In this multicenter trial with a 2-by-2 factorial design, we randomly assigned patients who had myocardial infarction to receive either colchicine or placebo and either spironolactone or placebo. The results of the colchicine trial are reported here. The primary efficacy outcome was a composite of death from cardiovascular causes, recurrent myocardial infarction, stroke, or unplanned ischemia-driven coronary revascularization, evaluated in a time-to-event analysis. C-reactive protein was measured at 3 months in a subgroup of patients, and safety was also assessed. Results A total of 7062 patients at 104 centers in 14 countries underwent randomization; at the time of analysis, the vital status was unknown for 45 patients (0.6%), and this information was most likely missing at random. A primary-outcome event occurred in 322 of 3528 patients (9.1%) in the colchicine group and 327 of 3534 patients (9.3%) in the placebo group over a median follow-up period of 3 years (hazard ratio, 0.99; 95% confidence interval [CI], 0.85 to 1.16; P=0.93). The incidence of individual components of the primary outcome appeared to be similar in the two groups. The least-squares mean difference in C-reactive protein levels between the colchicine group and the placebo group at 3 months, adjusted according to the baseline values, was −1.28 mg per liter (95% CI, −1.81 to −0.75). Diarrhea occurred in a higher percentage of patients with colchicine than with placebo (10.2% vs. 6.6%; P<0.001), but the incidence of serious infections did not differ between groups. Conclusions Among patients who had myocardial infarction, treatment with colchicine, when started soon after myocardial infarction and continued for a median of 3 years, did not reduce the incidence of the composite primary outcome (death from cardiovascular causes, recurrent myocardial infarction, stroke, or unplanned ischemia-driven coronary revascularization) [ABSTRACT FROM AUTHOR]

While team learning within engineering classrooms has been studied, minimal work has been done examining out-of-classroom collaboration to complete individual deliverables. However, such informal peer collaboration (IPC) is common among engineering undergraduates, and some evidence exists that low levels of IPC are associated with poorer learning outcomes. We aimed to explore beliefs, perceptions and actions toward IPC among engineering science instructors. We used a descriptive phenomenological approach to explore the instructors' experiences of IPC. Data from semi-structured interviews was analysed using inductive thematic analysis. Instructors identified positive (e.g. gaining confidence) and negative (e.g. overconfidence) outcomes of IPC. They believed that students used IPC for a range of needs and identified factors (e.g. language spoken) influencing IPC groupings. Most instructors only defined academic misconduct in syllabi, despite using implicit strategies (e.g. withholding solutions) to promote/inhibit IPC. Specific IPC policies were rarely connected to instructors' understanding of student motivations. Instructors view IPC as unavoidable and recognise that IPC may meet student needs while increasing or bypassing learning. Despite both using IPC as students and observing students now, instructors showed limited understanding of who participates. IPC may be an opportunity to increase learning among students; further research on barriers and pedagogy is warranted. [ABSTRACT FROM AUTHOR]

Abstract Background The optimal method of coronary revascularization for diabetes mellitus (DM) patients with left main coronary artery disease (LMCAD) is controversial in the drug-eluting stent (DES) era. Methods We performed a systematic review and meta-analysis comparing DES-based percutaneous coronary intervention (PCI) to coronary artery bypass grafting (CABG) for LMCAD in DM patients and tested for effect measure modification (EMM) by diabetes for adverse events. We included all randomized controlled trials (RCTs) and observational studies comparing CABG to DES-based PCI including DM patients with LMCAD published up to March 1, 2021. We completed separate random-effects meta-analyses for four RCTs (4356 patients, mean follow-up of 4.9 years) and six observational studies (9360 patients, mean follow-up of 5.2 years). Results In RCTs among DM patients, DES-based PCI, compared to CABG, was associated with a 30% increased relative risk (RR) (RR 1.30, 95% CI 1.09–1.56, I2 = 0%), while among non-DM patients, there was a 25% increased relative risk (RR 1.25, 95% CI 1.07–1.44, I2 = 0%) for the composite endpoint of all-cause mortality, myocardial infarction, stroke, and unplanned revascularization (MACCE). There was no evidence of EMM (p-value for interaction = 0.70). The mean weighted SYNTAX score was 25.7. In observational studies, there was no difference between DES-based PCI and CABG for all-cause mortality in patients with DM (RR 1.13, 95% CI 0.91–1.40, I2 = 0%). Conclusions CABG was superior to PCI for LMCAD in RCTs in DM patients for MACCE. Heart teams may consider DM as one of the many components in the clinical decision-making process, but may not want to consider DM as a primary deciding factor between DES-based PCI and CABG for LMCAD with low to intermediate anatomical complexity in the other coronary arteries. Study registration CRD42021246931 (PROSPERO).

In July 2021, a PCR-confirmed case of locally acquired Babesia microti infection was reported in Atlantic Canada. Clinical features were consistent with babesiosis and resolved after treatment. In a region where Lyme disease and anaplasmosis are endemic, the occurrence of babesiosis emphasizes the need to enhance surveillance of tickborne infections.

Abstract Background Two-dimensional speckle-tracking echocardiography (STE) may help detect coronary artery disease (CAD) when combined with dobutamine stress echocardiography. However, few studies have explored STE with exercise stress echocardiography (ESE). We aimed to evaluate the feasibility, reliability, and incremental value of STE combined with treadmill ESE compared to treadmill ESE alone to detect CAD. Methods We conducted a case–control study of all consecutive patients with abnormal ESE in 2018–2020 who subsequently underwent coronary angiography within a six-month interval. We 1:1 propensity score-matched these patients to those with a normal ESE. Two blinded operators generated a 17-segment bull's-eye map of longitudinal strain (LS). We utilized the mean differences between stress and baseline LS values in segments 13–17, segment 17, and segments 15–16 to create receiver operator curves for the overall examination, the left anterior descending artery (LAD), and the non-LAD territories, respectively. Results We excluded 61 STEs from 201 (30.3%) eligible ESEs; 47 (23.4%) because of suboptimal image quality and 14 (7.0%) because of excessive heart rate variability precluding the calculation of a bull's-eye map. After matching, a total of 102 patients were included (51 patients in each group). In the group with abnormal ESE patients (mean age 66.4 years, 39.2% female), 64.7% had significant CAD (> 70% stenosis) at coronary angiogram. In the group with normal ESE patients (mean age 65.1 years, 35.3% female), 3.9% were diagnosed with a new significant coronary stenosis within one year. The intra-class correlation for global LS was 0.87 at rest and 0.92 at stress, and 0.84 at rest, and 0.89 at stress for the apical segments. The diagnostic accuracy of combining ESE and STE was superior to visual assessment alone for the overall examination (area under the curve (AUC) = 0.89 vs. 0.84, p = 0.025), the non-LAD territory (AUC = 0.83 vs. 0.70, p = 0.006), but not the LAD territory (AUC = 0.79 vs. 0.73, p = 0.11). Conclusions Two-dimensional speckle-tracking combined with treadmill ESE is relatively feasible, reliable, and may provide incremental diagnostic value for the detection and localization of significant CAD.

This study measured resource utilization and costs for pre-school autism spectrum disorder (ASD)-related services in community-based sectors from multiple payer perspectives in two Canadian provinces, Nova Scotia (NS) and New Brunswick (NB), during the 12 months prior to and following the start of early intensive behavioural intervention (EIBI). The results indicate significant differences between NB and NS in utilization of services and costs to families, public sector and society. Differences can be attributed to variation in EIBI delivery models and may also be influenced by differences in diagnostic assessment practices. The study results provide resource utilization rates and costs which could be used in future economic evaluations and to inform policy making to improve outcomes for children with ASD.

In aluminum-clad spent nuclear fuels, an (oxy)hydroxide layer on the surface of the cladding hosts chemisorbed water formed during reactor and post-discharge exposure to water. Any residual water is susceptible to generating hydrogen via radiolysis, which can be a risk associated with dry fuel storage. Engineering-scale forced helium dehydration (FHD) and vacuum drying tests were conducted on mock-up fuel assemblies that included corroded aluminum surrogate plates to assess the removal of bulk and chemisorbed water. Thermogravimetric analysis was performed on samples of the surrogate plates, both undried control samples used to determine onset temperatures associated with a phase change occurring in the oxide layer and samples from drying tests used to determine the effectiveness of each drying method. Both vacuum drying and FHD processes were capable of removing bulk water. However, FHD was determined to provide additional drying capabilities, including partial removal of chemisorbed water from bayerite due to the higher temperatures during drying. The temperature threshold for partial dehydroxylation of the oxide layer was determined to be around 220°C, meaning any drying methods attempting to remove chemisorbed water must exceed 220°C. [ABSTRACT FROM AUTHOR]

Babesiosis is an emerging infectious disease caused by a zoonotic hemoprotozoan parasite of the genus Babesia, which consists of [approximately equal to]100 species (1-4). Human disease in North America is [...]

Salt marshes are ecosystems of significant ecological importance for coastal stability and fundamental roles in marine ecosystems. Salt marshes are declining due to anthropogenic and natural causes including sea level rise. Coastal restoration efforts have increased worldwide, but many fail in long-term coastal stability. We used a naturally occurring arbuscular mycorrhizal fungus (AMF) to test whether survival and early growth of the salt marsh grass Sporobolus pumilus (formerly Spartina patens) improved under simulated salt marsh conditions. Using a tidal mesocosm bench, we grew inoculated plants with varying AMF treatments under simulated tidal regimes to determine if AMF could aid in establishment of healthy Sporobolus communities. Rhizome-derived S. pumilus had greater survival and grew faster than seed-derived plants. Plants inoculated with propagated AMF consistently outperformed both sterile and native sediment controls in terms of plant survival and growth. Use of rhizome-derived Sporobolus inoculated with propagated Funneliformis geosporum showed the most promise in producing successful plant populations for salt marsh restoration. This may be due to plant life stage and improved plant nutrient status, allowing rhizome-derived plants to grow more quickly than seed-derived plants. Using these plants in future large-scale restoration may increase re-establishment of salt marsh ecosystems.

Using a one-dimensional code, we computed the power (enthalpy discharge rate) of a twelve-cell mechanical draft cooling tower (MDCT) using over two hundred visible condensed water vapor plume volume measurements derived from images, weather data, and tower operating conditions. The plume images were simultaneously captured by multiple stationary digital cameras surrounding the cooling tower. An analysis technique combining structure from motion (SfM), a neural-network-based image segmentation algorithm, and space carving was used to quantify the volumes. Afterwards, the power output was computed using novel techniques in the one-dimensional code that included cooling tower exhaust plume adjacency effects implemented with a modified version of the entrainment function, weather data averaged from eleven stations, and fan operations at the times when plume volumes were measured. The model was then compared with the averaged observed power output, and it validated well with an average error ranging from 6 to 12%, depending on the meteorological data used in the simulations. This methodology can possibly determine power plant fuel consumption rates by applying visible imagery.

This paper uses Geographic Information Systems (GIS) and dynamic mapping to examine student enrollments in New Jersey charter schools. Consistent with previous research, we find evidence of increased racial segregation. Greater percentages of African-Americans attend charter schools than reside in surrounding areas. We add to the existing charter school literature by more fully considering the importance of charter school supply and examining student enrollments across three geographic scales: school districts, census tracts and block groups. We demonstrate that racial segregation is most severe within charter schools' immediate neighborhoods (i.e. block groups), suggesting that analyses comparing charter schools to larger school districts or nearby public schools may misrepresent student sorting. This finding appears to result from the tendency of charter schools in New Jersey to cluster just outside predominately African-American neighborhoods, encircling the residential locations of the students they are most likely to enroll. (Contains 7 maps, 2 tables and 9 footnotes.)