First L-band Interferometric Observations of a Young Stellar Object: Probing the Circumstellar Environment of MWC 419

We present spatially-resolved K- and L-band spectra (at spectral resolution R = 230 and R = 60, respectively) of MWC 419, a Herbig Ae/Be star. The data were obtained simultaneously with a new configuration of the 85-m baseline Keck Interferometer. Our observations are sensitive to the radial distribution of temperature in the inner region of the disk of MWC 419. We fit the visibility data with both simple geometric and more physical disk models. The geometric models (uniform disk and Gaussian) show that the apparent size increases linearly with wavelength in the 2-4 microns wavelength region, suggesting that the disk is extended with a temperature gradient. A model having a power-law temperature gradient with radius simultaneously fits our interferometric measurements and the spectral energy distribution data from the literature. The slope of the power-law is close to that expected from an optically thick disk. Our spectrally dispersed interferometric measurements include the Br gamma emission line. The measured disk size at and around Br gamma suggests that emitting hydrogen gas is located inside (or within the inner regions) of the dust disk.Comment: Accepted for publication in Ap

Interferometric Observations of V838 Monocerotis

We have used long-baseline near-IR interferometry to resolve the peculiar eruptive variable V838 Mon and to provide the first direct measurement of its angular size. Assuming a uniform disk model for the emission we derive an apparent angular diameter at the time of observations (November-December 2004) of $1.83 \pm 0.06$ milli-arcseconds. For a nominal distance of $8\pm2$ kpc, this implies a linear radius of $1570 \pm 400 R_{\odot}$. However, the data are somewhat better fit by elliptical disk or binary component models, and we suggest that the emission may be strongly affected by ejecta from the outburst.Comment: 12 pages, 1 two-part encapsulated postscript figure. Accepted by ApJL. Added a table of observation

Protoplanetary Disk Masses in the Young NGC 2024 Cluster

We present the results from a Submillimeter Array survey of the 887 micron continuum emission from the protoplanetary disks around 95 young stars in the young cluster NGC 2024. Emission was detected from 22 infrared sources, with flux densities from ~5 to 330 mJy; upper limits (at 3sigma) for the other 73 sources range from 3 to 24 mJy. For standard assumptions, the corresponding disk masses range from ~0.003 to 0.2Msolar, with upper limits at 0.002--0.01Msolar. The NGC 2024 sample has a slightly more populated tail at the high end of its disk mass distribution compared to other clusters, but without more information on the nature of the sample hosts it remains unclear if this difference is statistically significant or a superficial selection effect. Unlike in the Orion Trapezium, there is no evidence for a disk mass dependence on the (projected) separation from the massive star IRS2b in the NGC 2024 cluster. We suggest that this is due to either the cluster youth or a comparatively weaker photoionizing radiation field.Comment: ApJ, in pres

ALMA Observations of the Largest Proto-Planetary Disk in the Orion Nebula, 114-426: A CO Silhouette

We present ALMA observations of the largest protoplanetary disk in the Orion Nebula, 114-426. Detectable 345 GHz (856 micron) dust continuum is produced only in the 350 AU central region of the ~1000 AU diameter silhouette seen against the bright H-alpha background in HST images. Assuming optically thin dust emission at 345 GHz, a gas-to-dust ratio of 100, and a grain temperature of 20 K, the disk gas-mass is estimated to be 3.1 +/- 0.6 Jupiter masses. If most solids and ices have have been incorporated into large grains, however, this value is a lower limit. The disk is not detected in dense-gas tracers such as HCO+ J=4-3, HCN J=4-3, or CS =7-6. These results may indicate that the 114-426 disk is evolved and depleted in some light organic compounds found in molecular clouds. The CO J=3-2 line is seen in absorption against the bright 50 to 80 K background of the Orion A molecular cloud over the full spatial extent and a little beyond the dust continuum emission. The CO absorption reaches a depth of 27 K below the background CO emission at VLSR ~6.7 km/s about 0.52 arcseconds (210 AU) northeast and 12 K below the background CO emission at VLSR ~ 9.7 km/s about 0.34 arcseconds (140 AU) southwest of the suspected location of the central star, implying that the embedded star has a mass less than 1 Solar mass .Comment: 20 pages, 4 figure

School-based interventions for reducing disciplinary school exclusion: a systematic review.

UNLABELLED: This Campbell systematic review examines the impact of interventions to reduce exclusion from school. School exclusion, also known as suspension in some countries, is a disciplinary sanction imposed by a responsible school authority, in reaction to students' misbehaviour. Exclusion entails the removal of pupils from regular teaching for a period during which they are not allowed to be present in the classroom (in-school) or on school premises (out-of-school). In some extreme cases the student is not allowed to come back to the same school (expulsion). The review summarises findings from 37 reports covering nine different types of intervention. Most studies were from the USA, and the remainder from the UK. Included studies evaluated school-based interventions or school-supported interventions to reduce the rates of exclusion. Interventions were implemented in mainstream schools and targeted school-aged children from four to 18, irrespective of nationality or social background. Only randomised controlled trials are included. The evidence base covers 37 studies. Thirty-three studies were from the USA, three from the UK, and for one study the country was not clear. School-based interventions cause a small and significant drop in exclusion rates during the first six months after intervention (on average), but this effect is not sustained. Interventions seemed to be more effective at reducing some types of exclusion such as expulsion and in-school exclusion. Four intervention types - enhancement of academic skills, counselling, mentoring/monitoring, and skills training for teachers - had significant desirable effects on exclusion. However, the number of studies in each case is low, so this result needs to be treated with caution. There is no impact of the interventions on antisocial behaviour. Variations in effect sizes are not explained by participants' characteristics, the theoretical basis of the interventions, or the quality of the intervention. Independent evaluator teams reported lower effect sizes than research teams who were also involved in the design and/or delivery of the intervention. PLAIN LANGUAGE SUMMARY: Interventions can reduce school exclusion but the effect is temporary: Some interventions - enhancement of academic skills, counselling, mentoring/monitoring, and skills training for teachers - appear to have significant effects on exclusion.The review in brief: Interventions to reduce school exclusion are intended to mitigate the adverse effects of this school sanction. Some approaches, namely those involving enhancement of academic skills, counselling, mentoring/monitoring and those targeting skills training for teachers, have a temporary effect in reducing exclusion. More evaluations are needed to identify the most effective types of intervention; and whether similar effects are also found in different countries.What is this review about?: School exclusion is associated with undesirable effects on developmental outcomes. It increases the likelihood of poor academic performance, antisocial behavior, and poor employment prospects. This school sanction disproportionally affects males, ethnic minorities, those who come from disadvantaged economic backgrounds, and those with special educational needs.This review assesses the effectiveness of programmes to reduce the prevalence of exclusion.What are the main findings of this review?: What studies are included? Included studies evaluated school-based interventions or school-supported interventions to reduce the rates of exclusion. Interventions were implemented in mainstream schools and targeted school-aged children from four to 18, irrespective of nationality or social background. Only randomised controlled trials are included.The evidence base covers 37 studies. Thirty-three studies were from the USA, three from the UK, and for one study the country was not clear.School-based interventions cause a small and significant drop in exclusion rates during the first six months after intervention (on average), but this effect is not sustained. Interventions seemed to be more effective at reducing some types of exclusion such as expulsion and in-school exclusion.Four intervention types - enhancement of academic skills, counselling, mentoring/ monitoring, and skills training for teachers - had significant desirable effects on exclusion. However, the number of studies in each case is low, so this result needs to be treated with caution.There is no impact of the interventions on antisocial behaviour.Variations in effect sizes are not explained by participants' characteristics, the theoretical basis of the interventions, or the quality of the intervention. Independent evaluator teams reported lower effect sizes than research teams who were also involved in the design and/or delivery of the intervention.What do the findings of this review mean?: School-based interventions are effective at reducing school exclusion immediately after, and for a few months after, the intervention (6 months on average). Four interventions presented promising and significant results in reducing exclusion, that is, enhancement of academic skills, counselling, mentoring/monitoring, skills training for teachers. However, since the number of studies for each sub-type of intervention was low, we suggest these results should be treated with caution.Most of the studies come from the USA. Evaluations are needed from other countries in which exclusion is common. Further research should take advantage of the possibility of conducting cluster-randomised controlled trials, whilst ensuring that the sample size is sufficiently large.How up-to-date is this review?: The review authors searched for studies published up to December 2015. This Campbell systematic review was published in January 2018. EXECUTIVE SUMMARY/ABSTRACT: BACKGROUND: Schools are important institutions of formal social control (Maimon, Antonaccio, & French, 2012). They are, apart from families, the primary social system in which individuals are socialised to follow specific codes of conduct. Violating these codes of conduct may result in some form of punishment. School punishment is normally accepted by families and students as a consequence of transgression, and in that sense school isoften the place where children are first introduced to discipline, justice, or injustice (Whitford & Levine-Donnerstein, 2014).A wide range of punishments may be used in schools, from verbal reprimands to more serious actions such as detention, fixed term exclusion or even permanent exclusion from the mainstream education system. It must be said that in some way, these school sanctions resemble the penal system and its array of alternatives to punish those that break the law.School exclusion, also known as suspension in some countries, is defined as a disciplinary sanction imposed by a responsible school authority, in reaction to students' misbehaviour. Exclusion entails the removal of pupils from regular teaching for a period during which they are not allowed to be present in the classroom or, in more serious cases, on school premises.Based on the previous definition, this review uses school exclusion and school suspension as synonyms, unless the contrary is explicitly stated. Most of the available research has found that exclusion correlates with subsequent negative sequels on developmental outcomes. Exclusion or suspension of students is associated with failure within the academic curriculum, aggravated antisocial behaviour, and an increased likelihood of involvement with punitive social control institutions (i.e., the Juvenile Justice System). In the long-term, opportunities for training and employment seem to be considerably reduced for those who have repeatedly been excluded. In addition to these negative correlated outcomes, previous evidence suggest that the exclusion of students involves a high economic cost for taxpayers and society.Research from the last 20 years has concluded quite consistently that this disciplinary measure disproportionally targets males, ethnic minorities, those who come from disadvantaged economic backgrounds, and those presenting special educational needs. In other words, suspension affects the most vulnerable children in schools.Different programmes have attempted to reduce the prevalence of exclusion. Although some of them have shown promising results, so far, no comprehensive systematic review has examined these programmes' overall effectiveness.OBJECTIVES: The main goal of the present research is to systematically examine the available evidence for the effectiveness of different types of school-based interventions aimed at reducing disciplinary school exclusion. Secondary goals include comparing different approaches and identifying those that could potentially demonstrate larger and more significant effects.The research questions underlying this project are as follows: Do school-based programmes reduce the use of exclusionary sanctions in schools?Are some school-based approaches more effective than others in reducing exclusionary sanctions?Do participants' characteristics (e.g., age, gender, ethnicity) affect the impact of school-based programmes on exclusionary sanctions in schools?Do characteristics of the interventions, implementation, and methodology affect the impact of school-based programmes on exclusionary sanctions in schools? SEARCH METHODS: The authors conducted a comprehensive search to locate relevant studies reporting on the impact of school-based interventions on exclusion from 1980 onwards. Twenty-seven different databases were consulted, including databases that contained both published and unpublished literature. In addition, we contacted researchers in the field of school-exclusion for further recommendations of relevant studies; we also assessed citation lists from previous systematic and narrative reviews and research reports. Searches were conducted from September 1 to December 1, 2015.SELECTION CRITERIA: The inclusion and exclusion criteria for manuscripts were defined before we started our searches. To be eligible, studies needed to have: evaluated school-based interventions or school-supported interventions intended to reduce the rates of suspension; seen the interventions as an alternative to exclusion; targeted school-aged children from four to 18 in mainstream schools irrespective of nationality or social background; and reported results of interventions delivered from 1980 onwards. In terms of methodological design, we included randomised controlled trialsonly, with at least one experimental group and onecontrol or placebo group.DATA COLLECTION AND ANALYSIS: Initial searches produced a total of 42,749 references from 27 different electronic databases. After screening the title, abstract and key words, we kept 1,474 relevant hits. 22 additional manuscripts were identified through other sources (e.g., assessment of citation lists, contribution of authors). After removing duplicates, we ended up with a total of 517 manuscripts. Two independent coders evaluated each report, to determine inclusion or exclusion.The second round of evaluation excluded 472 papers, with eight papers awaiting classification, and 37 studies kept for inclusion in meta-analysis. Two independent evaluators assessed all the included manuscripts for risk of quality bias by using EPOC tool.Due to the broad scope of our targeted programmes, meta-analysis was conducted under a random-effect model. We report the impact of the intervention using standardised differences of means, 95% confidence intervals along with the respective forest plots. Sub-group analysis and meta-regression were used for examining the impact of the programme. Funnel plots and Duval and Tweedie's trim-and-fill analysis were used to explore the effect of publication bias.RESULTS: Based on our findings, interventions settled in school can produce a small and significant drop in exclusion rates (SMD=.30; 95% CI .20 to .41; p<.001). This means that those participating in interventions are less likely to be suspended than those allocated to control/placebo groups. These results are based on measures of impact collected immediately during the first six months after treatment (on average). When the impact was tested in the long-term (i.e., 12 or more months after treatment), the effects of the interventions were not sustained. In fact, there was a substantive reduction in the impact of school-based programmes (SMD=.15; 95%CI -.06 to .35), and it was no longer statistically significant.We ran analysis testing the impact of school-based interventions on different types of exclusion. Evidence suggests that interventions are more effective at reducing expulsion and in-school exclusion than out-of-school exclusion. In fact, the impact of intervention in out-of-school exclusion was close to zero and not statistically significant.Nine different types of school-based interventions were identified across the 37 studies included in the review. Four of them presented favourable and significant results in reducing exclusion (i.e., enhancement of academic skills, counselling, mentoring/monitoring, skills training for teachers). Since the number of studies for each sub-type of intervention was low, we suggest that results should be treated with caution.A priori defined moderators (i.e., participants' characteristics, the theoretical basis of the interventions, and quality of the intervention)showed not to be effective at explaining the heterogeneity present in our results. Among three post-hoc moderators, the role of the evaluator was found to be significant: independent evaluator teams reported lower effect sizes than research teams who were also involved in the design and/or delivery of the intervention.Two researchers independently evaluated the quality of the evidence involved in this review by using the EPOC tool. Most of the studies did not present enough information for the judgement of quality bias.AUTHORS' CONCLUSIONS: The evidence suggests that school-based interventions are effective at reducing school exclusion immediately after, and for a few months after, the intervention. Some specific types of interventions show more promising and stable results than others, namely those involving mentoring/monitoring and those targeting skills training for teachers. However, based on the number of studies involved in our calculations, we suggest that results must be cautiously interpreted. Implications for policy and practice arising from our results are discussed

Properties of the Bare Nucleus of Comet 96P/Machholz 1

We observed comet 96P/Machholz 1 on a total of nine nights before and after perihelion during its 2017/2018 apparition. Both its unusually small perihelion distance and the observed fragmentation during multiple apparitions make 96P an object of great interest. Our observations show no evidence of a detectable dust coma, implying that we are observing a bare nucleus at distances ranging from 2.3 to 3.8 au. Based on this assumption, we calculated its color and found average values of g'–r' = 0.50 ± 0.04, r'–i' = 0.17 ± 0.03, and i'–z' = 0.06 ± 0.04. These are notably more blue than those of the nuclei of other Jupiter-family and long-period comets. Furthermore, assuming a bare nucleus, we found an equivalent nuclear radius of 3.4 ± 0.2 km with an axial ratio of at least 1.6 ± 0.1. The lightcurve clearly displays one large peak, one broad flat peak, and two distinct troughs, with a clear asymmetry that suggests that the shape of the nucleus deviates from that of a simple triaxial ellipsoid. This asymmetry in the lightcurve allowed us to constrain the nuclear rotation period to 4.10 ± 0.03 hr and 4.096 ± 0.002 hr before and after perihelion, respectively. Within the uncertainties, 96P's rotation period does not appear to have changed throughout the apparition, and we conclude a maximum possible change in rotation period of 130 s. The observed properties were compared to those of comet 322P and interstellar object 1I/'Oumuamua in an attempt to study the effects of close perihelion passages on cometary surfaces and their internal structure and the potential interstellar origin of 96P

Two Late Quaternary Pollen Records from South-Central Alaska

Pollen records from Wonder and Ten Mile lakes, located at aititudinal treeline to the north and south of the Alaska Range respectively, document the vegetation history of a portion of the southern Alaskan boreal forest. The new pollen diagrams indicate a Betula shrub tundra, preceded at Wonder Lake by a sparse herb tundra, which characterized these two areas during latest Wisconsinan times. Populus was in the vicinity of Ten Mile Lake ca. 10,000 BP, but was apparently absent from Wonder Lake. Picea glauca grew at or near Ten Mile Lake by 9100 BP, with P. mariana becoming important ca. 7000 BP. The first forests at Wonder Lake were also dominated by P. glauca and followed by increased numbers of P. mariana. The timing of forest establishment at Wonder Lake is uncertain due to problematic radiocarbon dates. Alnus appears to be common in both regions by ca. 7000 BP. These records suggest that paleo-vegetational reconstructions are more difficult for the southern than northern boreal forests in Alaska because of greater topographic diversity, difficulties with over-representation of some pollen taxa, and problems with radiocarbon dating. Despite these concerns, available data from south-central Alaska suggest that southern and northern forests differ in their vegetational histories. Such differences, when related to temperature fluctuations that have been postulated for the Holocene, imply that the Alaskan boreal forest may not respond uniformly to future global warming.Les inventaires polliniques de Wonder Lake et de Ten Mile Lake, situés à la limite altitudinale des arbres au nord et au sud de la chaîne de l'Alaska permettent de reconstituer l'histoire de la végétation d'une portion de la forêt boréale du sud de l'Alaska. Les nouveaux diagrammes polliniques montrent une toundra arbustive à Betula, précédée au Wonder Lake par une toundra herbacée clairsemée, à la fin du Wisconsinien. Vers 10 000 BP, Populus était dans les environs du Ten Mile Lake, mais était apparamment absent du Wonder Lake. Picea glauca croissait autour du Ten Mile Lake à 9100 BP et P. mariana prenait de l'importance vers 7000 BP. Au Wonder Lake, les premières forêts ont également été dominées par P. glauca, puis par un nombre croissant de P. mariana. La chronologie de !'afforestation est incertaine en raison de datations au radiocarbone douteuses. Alnus semble être une espèce courante dans les deux régions vers 7000 BP. Les inventaires indiquent que la reconstitution de la paléovégétation est plus difficile à faire pour les forêts méridionales que septentrionales de l'Alaska, en raison de la plus grande diversité topographique, la sur-représentation de certains taxons et des problèmes de radio-datation. Les données indiquent tout de même que l'histoire de la végétation des forêts diffèrent au nord et au sud. Ces différences, mises en relation avec les fluctuations de températures présumées de l'Holocène, laissent croire que la forêt de l'Alaska ne répondra pas nécessairement de façon uniforme à un réchauffement climatique éventuel.DbiJibneBbie aiiarpa.viMbi ocaaKOB 03ep Baeae n TeHMaRJi, pacnojioxeHiibix B6JIII3H Bepxiiert rpaiiMUbi Jieca Ha ceBepe H wre A/iflCKiiHCKoro xpeôîa, OTpaacaioT ncropnio pacTHTejibHOCTH KOKIIOH lacr" Sopea/ibHoro jieca AJIBCKH. HoBbie ribiJibuebe anarpaMMbi iiOKaabiBaioT, HTO KycTapmiKOBOfi 6epr30B0fi TyHApe, xapaKTepiioft aJifl 3TMX aByx TeppiiTopufl B Teieime no3iuiero BiicKoiicmia, npemuecTBOBajia B oTaoaceiinnx 03. Banae 6emiaH TpaBHHUCTHa iyHapa. Populus iipopn3parra.n B otcpecruocnix 03. Teii.vianji 10000 /J.H., HO, JlO-BIUHMOMy, OTCyTCTBOBaa B pafione 03. BaHae. 9100 JI.H. B panoHe 03. Tenvianj] H.11I B iienocpeacrBeimoH 6/IH30CTH OT iiero npoH3pacTajia Picea glauca, KOTopan BMepTe c Picea mariana nrpaeT 3Ha'iiiTe/ibnyio pojib B codaBe pacTHTeJibHOCTM OKO/IO 7000 .i.n. B nepBbix Jiecax B paflone 03. BaHae TaKjKe aoMiiiuipoBajia Picea glauca, 110 3aTe,vi pojib Picea mariana iiaHimaeT B03pacacTaTb. Bpe.viH noflB/ieiiHfl jiecoB B panone 03. Banae uoKaiie ycraiiaBJiiiBaeTca iiaaeacHo paaiioyr-jiepoaiibiM McroaoM. Alnus o6pa3yer cooBiuecTBa B06011X pafioiiax OKOJIO 7000 JI.H. nojiyieiuibie aaiiHbie cBiiaeTejibCTByioT 0 TOM, HTO peKoiicTpyKniifl pacTiiTejibiiocTH 6yaer 6ojieecjio>KHon aJin lOîKHbix, ieM aJifl ceaepiibix 6opeajibiibix JiecoB AJIHCKH 1133a SHa'iinejibiioro TonorpafpimecKoro iiecxoacTBa,3aTpyaiieiii!Ji B iiHTepnpeTaumi neKOTopwx nbijibneitbix TaKCOHOB, npoGjieM c paanoyrjiepoaiibiM aaTHpBaiine.M. HeavioTpa tia 3TH npo6jieivibi, nojicpieHHbie aaHiibie noKa3biaiOT, HTO fjopeajibiibie Jieca 11a wre 11 ceBepe ioaciion iacni UetiTajibiion AJIHCKH wweioT pa3Jiiiiyio iiCTopnio. TaKiie pa3Jinmtfl, cBfl3xaiuibie c n3MeiieiijiflMii 3eMJiepaTyp B Teieiuie ro.'ioueiia, cBiiae-Te.TbCTByioT, HTO 6opeajibiibiri Jiec AJIHCKH ,vioxer ne OTBenaTb cienapnio rjio6aJibiioro noTen.ieiina u SyaymeM

Science with the Keck Interferometer ASTRA Program

The ASTrometric and phase-Referenced Astronomy (ASTRA) project will provide phase referencing and astrometric observations at the Keck Interferometer, leading to enhanced sensitivity and the ability to monitor orbits at an accuracy level of 30-100 microarcseconds. Here we discuss recent scientific results from ASTRA, and describe new scientific programs that will begin in 2010-2011. We begin with results from the "self phase referencing" (SPR) mode of ASTRA, which uses continuum light to correct atmospheric phase variations and produce a phase-stabilized channel for spectroscopy. We have observed a number of protoplanetary disks using SPR and a grism providing a spectral dispersion of ~2000. In our data we spatially resolve emission from dust as well as gas. Hydrogen line emission is spectrally resolved, allowing differential phase measurements across the emission line that constrain the relative centroids of different velocity components at the 10 microarcsecond level. In the upcoming year, we will begin dual-field phase referencing (DFPR) measurements of the Galactic Center and a number of exoplanet systems. These observations will, in part, serve as precursors to astrometric monitoring of stellar orbits in the Galactic Center and stellar wobbles of exoplanet host stars. We describe the design of several scientific investigations capitalizing on the upcoming phase-referencing and astrometric capabilities of ASTRA.Comment: Published in the proceedings of the SPIE 2010 conference on "Optical and Infrared Interferometry II