A Near-Infrared L Band Survey of the Young Embedded Cluster NGC 2024

We present the results of the first sensitive L band (3.4 micron) imaging study of the nearby young embedded cluster NGC 2024. Two separate surveys of the cluster were acquired in order to obtain a census of the circumstellar disk fraction in the cluster. From an analysis of the JHKL colors of all sources in our largest area, we find an infrared excess fraction of > 86%. The JHKL colors suggest that the infrared excesses arise in circumstellar disks, indicating that the majority of the sources which formed in the NGC 2024 cluster are currently surrounded by, and likely formed with circumstellar disks. The excess fractions remain very high, within the errors, even at the faintest L magnitudes from our deeper surveys suggesting that disks form around the majority of the stars in very young clusters such as NGC 2024 independent of mass. From comparison with published JHKL observations of Taurus, we find the K - L excess fraction in NGC 2024 to be consistent with a high initial incidence of circumstellar disks in both NGC 2024 and Taurus. Because NGC 2024 represents a region of much higher stellar density than Taurus, this suggests that disks may form around most of the YSOs in star forming regions independent of environment. We find a relatively constant JHKL excess fraction with increasing cluster radius, indicating that the disk fraction is independent of location in the cluster. In contrast, the JHK excess fraction increases rapidly toward the central region of the cluster, and is most likely due to contamination of the K band measurements by bright nebulosity in the central regions of the cluster. We identify 45 candidate protostellar sources in the central regions of the NGC 2024 cluster, and find a lower limit on the protostellar phase of early stellar evolution of 0.4 - 1.4 X 10^5 yr, similar to that in Taurus.Comment: 37 pages, 8 figures, 3 tables, To appear in the Astronomical Journa

Model Selection in Variational Mixed Effects Models

Variational inference is an alternative estimation technique for Bayesian models. Recent work shows that variational methods provide consistent estimation via efficient, deterministic algorithms. Other tools, such as model selection using variational AICs (VAIC) have been developed and studied for the linear regression case. While mixed effects models have enjoyed some study in the variational context, tools for model selection are lacking. One important feature of model selection in mixed effects models, particularly longitudinal models, is the selection of the random effects which in turn determine the covariance structure for the repeatedly sampled outcome. To address this, we derive a VAIC specifically for variational mixed effects (VME) models. We also implement a parameter-efficient VME as part of our study which reduces any general random effects structure down to a single subject-specific score. This model accommodates a wide range of random effect structures including random intercept and slope models as well as random functional effects. Our VAIC can model and perform selection on a variety of VME models including more classic longitudinal models as well as longitudinal scalar-on-function regression. As we demonstrate empirically, our VAIC performs well in discriminating between correctly and incorrectly specified random effects structures. Finally, we illustrate the use of VAICs for VMEs on two datasets: a study of lead levels in children and a study of diffusion tensor imaging

The Trypanosoma cruzi enzyme TcGPXI is a glycosomal peroxidase and can be linked to trypanothione reduction by glutathione or tryparedoxin.

Trypanosoma cruzi glutathione-dependent peroxidase I (TcGPXI) can reduce fatty acid, phospholipid, and short chain organic hydroperoxides utilizing a novel redox cycle in which enzyme activity is linked to the reduction of trypanothione, a parasite-specific thiol, by glutathione. Here we show that TcGPXI activity can also be linked to trypanothione reduction by an alternative pathway involving the thioredoxin-like protein tryparedoxin. The presence of this new pathway was first detected using dialyzed soluble fractions of parasite extract. Tryparedoxin was identified as the intermediate molecule following purification, sequence analysis, antibody studies, and reconstitution of the redox cycle in vitro. The system can be readily saturated by trypanothione, the rate-limiting step being the interaction of trypanothione with the tryparedoxin. Both tryparedoxin and TcGPXI operate by a ping-pong mechanism. Overexpression of TcGPXI in transfected parasites confers increased resistance to exogenous hydroperoxides. TcGPXI contains a carboxyl-terminal tripeptide (ARI) that could act as a targeting signal for the glycosome, a kinetoplastid-specific organelle. Using immunofluorescence, tagged fluorescent proteins, and biochemical fractionation, we have demonstrated that TcGPXI is localized to both the glycosome and the cytosol. The ability of TcGPXI to use alternative electron donors may reflect their availability at the corresponding subcellular sites

NEPC Review: Smart, Skilled, and Striving: Transforming and Elevating the Teaching Profession

This report from the Center for American Progress offers 10 recommendations for improving the public perceptions of and experiences of classroom teachers. While elements of these recommendations would likely be beneficial, they also include policy changes that would increase surveillance of teachers, reduce teachers&rsquo; job security, evaluate teachers by students&rsquo; test scores, and create merit pay systems that would likely have the opposite effect. For evidence, the report relies too heavily on popular rhetoric, sound bites, opinion articles, and advocacy publications to advance a policy agenda that in many ways could do further harm to the teaching profession. However, many of the report&rsquo;s recommendations do align with policy reforms currently being proposed for the Higher Education Act and included in the Elementary and Secondary Education Act reauthorizations and are therefore important to read critically and consider carefully. In advancing evaluation of teachers by test scores, the report goes against the cautions and guidelines recently released by the American Statistical Association and the American Educational Research Association. Other than a review of contemporary issues, the report offers little of substance to advance the teaching profession.</p

Site-specific identification and quantitation of endogenous SUMO modifications under native conditions.

Small ubiquitin-like modifier (SUMO) modification regulates numerous cellular processes. Unlike ubiquitin, detection of endogenous SUMOylated proteins is limited by the lack of naturally occurring protease sites in the C-terminal tail of SUMO proteins. Proteome-wide detection of SUMOylation sites on target proteins typically requires ectopic expression of mutant SUMOs with introduced tryptic sites. Here, we report a method for proteome-wide, site-level detection of endogenous SUMOylation that uses α-lytic protease, WaLP. WaLP digestion of SUMOylated proteins generates peptides containing SUMO-remnant diglycyl-lysine (KGG) at the site of SUMO modification. Using previously developed immuno-affinity isolation of KGG-containing peptides followed by mass spectrometry, we identified 1209 unique endogenous SUMO modification sites. We also demonstrate the impact of proteasome inhibition on ubiquitin and SUMO-modified proteomes using parallel quantitation of ubiquitylated and SUMOylated peptides. This methodological advancement enables determination of endogenous SUMOylated proteins under completely native conditions

Teachers’ professional learning to affirm transgender, non-binary, and gender-creative youth: Experiences and recommendations from the field

This article critically examines the professional learning needs called for by educators working to support transgender, non-binary, and gender-creative (trans) youth and makes recommendations for practice. Interviews were conducted with 26 educators (preschool to secondary) who have worked directly with trans students (any child whose behaviour does not match stereotypes for their sex category assigned at birth, or who identifies with a gender different from their sex category assigned at birth). We examine two new concepts related to professional learning and educator preparation that emerged from theorising the data and related literature: pedagogies of exposure and culture of conversation. The limits and possibilities offered by these approaches are critically examined through the research base on teacher learning. Recommendations are made for teacher preparation, professional development and related practices to better create and sustain learning environments that affirm gender diversity

Coordenadores do Título IX como burocratas de nível de rua nas escolas dos Estados Unidos: Desafios para enfrentar a discriminação sexual na era #MeToo

Sex discrimination in educational contexts is an ongoing problem despite the passage of Title IX in 1972. Many schools have not aligned their policies with new laws protecting students from bullying and harassment, and many professionals are unaware of their new obligations in regards to new state regulations. This article presents the findings from semi-structured interviews with 10 participants reporting on the roles and responsibilities of Title IX coordinators in their K-12 school districts. Title IX coordinators were difficult to locate and recruitment was a challenge in this study. However, our findings indicate a strong alignment with Lipsky’s concept of “street-level bureaucrats” (1971, 2010). We found that these school administrators had autonomy and discretion in interpreting and enacting their duties, however they lacked time, information, and other resources necessary to respond properly to the stated duties in their position. They reported spending very little time on Title IX-related duties, many felt under-supported and under-prepared, and few had comprehensive understanding of their responsibilities. We conclude with recommendations for policy and practice regarding the training and supports of Title IX coordinators and related gender equity efforts in K-12 schools.La discriminación sexual en contextos educativos es un problema continuo a pesar de la aprobación del Título IX en 1972. Muchas escuelas no han alineado sus políticas con nuevas leyes que protegen a los estudiantes de la intimidación y el acoso, y muchos profesionales desconocen sus nuevas obligaciones con respecto a regulaciones estatales Este artículo presenta los hallazgos de entrevistas semiestructuradas con 10 participantes que informan sobre los roles y responsabilidades de los coordinadores del Título IX en sus distritos escolares K-12. Los coordinadores del Título IX fueron difíciles de localizar y el reclutamiento fue un desafío en este estudio. Sin embargo, nuestros hallazgos indican una fuerte alineación con el concepto de Lipsky de "burócratas a nivel de calle" (1971, 2010). Descubrimos que estos administradores escolares tenían autonomía y discreción para interpretar y cumplir sus deberes, sin embargo, carecían de tiempo, información y otros recursos necesarios para responder adecuadamente a los deberes establecidos en su puesto. Informaron que dedicaron muy poco tiempo a los deberes relacionados con el Título IX, muchos se sintieron insuficientemente apoyados y poco preparados, y pocos tenían una comprensión exhaustiva de sus responsabilidades. Concluimos con recomendaciones de políticas y prácticas con respecto a la capacitación y el apoyo de los coordinadores del Título IX y los esfuerzos relacionados con la equidad de género en las escuelas K-12.A discriminação sexual em ambientes educacionais é um problema contínuo, apesar da aprovação do Título IX em 1972. Muitas escolas não alinharam suas políticas com novas leis que protegem os alunos de intimidação e assédio, e muitos profissionais desconhecem seus direitos. novas obrigações com relação aos regulamentos estaduais Este artigo apresenta os resultados de entrevistas semi-estruturadas com 10 participantes que relatam os papéis e responsabilidades dos coordenadores do Título IX em seus distritos escolares K-12. Os coordenadores do Título IX foram difíceis de localizar e o recrutamento foi um desafio neste estudo. No entanto, nossos resultados indicam um forte alinhamento com o conceito de "burocratas de rua" de Lipsky (1971, 2010). Descobrimos que esses administradores escolares tinham autonomia e discrição para interpretar e cumprir suas obrigações, no entanto, eles não tinham tempo, informações e outros recursos necessários para responder adequadamente aos deveres estabelecidos em sua posição. Eles relataram que gastaram muito pouco tempo em tarefas relacionadas ao Título IX, muitos se sentiram insuficientemente apoiados e despreparados, e poucos tinham uma compreensão abrangente de suas responsabilidades. Concluímos com recomendações e práticas de políticas relacionadas à formação e apoio de coordenadores do Título IX e esforços relacionados à eqüidade de gênero nas escolas do ensino fundamental e médio

Home-based tuberculosis contact investigation in Uganda: a household randomised trial.

IntroductionThe World Health Organization (WHO) recommends household tuberculosis (TB) contact investigation in low-income countries, but most contacts do not complete a full clinical and laboratory evaluation.MethodsWe performed a randomised trial of home-based, SMS-facilitated, household TB contact investigation in Kampala, Uganda. Community health workers (CHWs) visited homes of index patients with pulmonary TB to screen household contacts for TB. Entire households were randomly allocated to clinic (standard-of-care) or home (intervention) evaluation. In the intervention arm, CHWs offered HIV testing to adults; collected sputum from symptomatic contacts and persons living with HIV (PLWHs) if ≥5 years; and transported sputum for microbiologic testing. CHWs referred PLWHs, children &lt;5 years, and anyone unable to complete sputum testing to clinic. Sputum testing results and/or follow-up instructions were returned by automated SMS texts. The primary outcome was completion of a full TB evaluation within 14 days; secondary outcomes were TB and HIV diagnoses and treatments among screened contacts.ResultsThere were 471 contacts of 190 index patients allocated to the intervention and 448 contacts of 182 index patients allocated to the standard-of-care. CHWs identified 190/471 (40%) intervention and 213/448 (48%) standard-of-care contacts requiring TB evaluation. In the intervention arm, CHWs obtained sputum from 35/91 (39%) of sputum-eligible contacts and SMSs were sent to 95/190 (50%). Completion of TB evaluation in the intervention and standard-of-care arms at 14 days (14% versus 15%; difference -1%, 95% CI -9% to 7%, p=0.81) and yields of confirmed TB (1.5% versus 1.1%, p=0.62) and new HIV (2.0% versus 1.8%, p=0.90) diagnoses were similar.ConclusionsHome-based, SMS-facilitated evaluation did not improve completion or yield of household TB contact investigation, likely due to challenges delivering the intervention components