Accretion rate of extraterrestrial matter: Iridium deposited over the last 70 million years

In order to quantify the accretion rate of extraterrestrial matter during the Cenozoic, Ir concentrations were measured in a continuous series of 450 samples across most of the length of piston core LL44-GPC3. LL44-GPC3 is a 25-meter-long, large-diameter piston core of abyssal clay from the central North Pacific. This core contains a nearly continuous record of sedimentation over the last 70 Ma, as this site migrated from a region near the Equator in the late Cretaceous to its present position north of Hawaii. The first-cut survey across the core is nearing completion, and all of the conclusions of the earlier study, in which was reported the concentrations of Ir, Co, and Sb across 9 meters of this core, remain unchanged. The only strongly enhanced Ir concentrations occur at the Cretaceous-Tertiary (K-T) boundary and outside the K-T boundary Ir correlates well with Co, a terrestrial element which is largely present in hydrogenous ferromanganese oxide precipitates from seawater. Concentrations of both elements appear to be inversely correlated with the sedimentation rate. Although the K-T Ir anomaly is unique in magnitude in this core, there are several small bumps in the Ir profile which may reflect smaller accretionary events. The most promising Ir enhancement was observed in a 30 cm section approximately 1 m below the K-T boundary. Preliminary data suggest deposition of an excess across this interval at a time estimate to be approximate 1 Ma before the K-T impact event, but there is insufficient evidence at present to prove that this reflects enhanced accretion of extraterrestrial matter. A detailed model is being prepared of the chemical record of sedimentation in this core using a combined database of 39 elements in approximately 450 samples across the Cenozoic. Preliminary working model indicates that the only sedimentary sources which contribute significantly to the Ir budget in this core are the hydrogenous precipitates and extraterrestrial particulates

Are the stratospheric dust particles meteor ablation debris or interplanetary dust?

Natural and laboratory created fusion crusts and debris from artificial meteor samples were used to develop criteria for recognizing meteor ablation debris in a collection of 5 to 50 micron particles from the stratosphere. These laboratory studies indicate that meteor ablation debris from nickel-iron meteoroids produce spherules containing taenite, wuestite, magnetite, and hematite. These same studies also indicate that ablation debris from chondritic meteoroids produce spheres and fragmentary debris. The spheres may be either silicate rich, containing zoned olivine, magnetite, and glass, or sulfide rich, containing iron oxides (e.g., magnetite, wuestite) and iron sulfides (e.g., pyrrhotite, pentlandite). The fragmentary debris may be either fine-grained aggregates of olivine, magnetite, pyroxene, and occasionally pyrrhotite (derived from the meteorite matrix) or individual olivine and pyroxene grains (derived from meteorite inclusions)

Students' self-assessment in spiritual care in clinical placement

Poster presentert på den internasjonale konferfansen “Spiritiual Care - The State of the Art and International Perspectives”, 18.oktober 2019 i Bergen

Genetic Code: A New Understanding of Codon - Amino Acid Assignment

In this work it is shown that 20 canonical amino acids (AAs) within genetic code appear to be a whole system with strict AAs positions; more exactly, with AAs ordinal number in three variants; first variant 00-19, second 00-21 and third 00-20. The ordinal number follows from the positions of belonging codons, i.e. their digrams (or doublets). The reading itself is a reading in quaternary numbering system if four bases possess the values within a specific logical square: A = 0, C = 1, G = 2, U = 3. By this, all splittings, distinctions and classifications of AAs appear to be in accordance to atom and nucleon number balance as well as to the other physico-chemical properties, such as hydrophobicity and polarity.Comment: 25 Pages, 8 Tables, 5 Figures and 5 Surveys. The paper is submitting to GLASNIK of Montenegrin Academy of Science and Arts as a extended version of paper published in Ann. N.Y. Acad. Sci. 1048: 517-523 (2005

Overrepresentation and disparity of Black children reported under the child protection system : the need for effective cross-system collaborations

Élaborée à partir de trois articles, cette thèse vise à développer une compréhension plus approfondie de la surreprésentation des enfants Noirs suivis par le système de protection de l’enfance au Canada. Le premier et le deuxième article examinent les taux de disparité des enfants faisant l’objet d’un signalement au Centre Jeunesse pour un échantillon d’enfants Noirs, Blancs et d’autres minorités racisées résidant à Montréal, Québec. Les résultats du premier article indiquent que comparativement aux enfants Blancs, les enfants Noirs étaient cinq fois plus susceptibles d’avoir leur signalement retenu et que le motif de celui-ci se révèle fondé. Le taux de placement était également cinq fois plus élevé que celui des enfants Blancs. Les résultats du deuxième article révèlent des différences dans la durée de placement et la probabilité d’une réunification familiale. Lorsqu’on compare la durée de placement des enfants Noirs, Blancs et d’autres minorités racisées, les enfants Noirs avaient une durée de placement plus longue. De plus ces enfants étaient moins susceptibles de réintégrer leur famille une fois le placement terminé. Cette probabilité réduite de réunification familiale s’explique statistiquement par l’impact de trois variables : l’instabilité du placement, l’âge de l’enfant et le type de maltraitance subie. Il est suggéré que l’accessibilité des services de soutien social au sein de la communauté de l’enfant est un facteur qui permet de protéger contre la pauvreté et diminuer la surreprésentation des enfants Noirs. Le troisième article dans cette thèse s’appuie sur une enquête qualitative conçue à partir d’une approche thématique afin d’identifier certains défis engendrés par la collaboration entre un Centre Jeunesse et un organisme communautaire. La création d’un partenariat a été proposée comme solution visant la réduction de la surreprésentation des enfants Noirs pris en charge par le Centre Jeunesse. Il s’agit d’une collaboration ayant pour but de rehausser les conditions socioéconomiques des ménages tout en permettant d’offrir un éventail de services plus adaptés aux particularités culturelles des parents noirs. Des entrevues semi-structurées ont été menées auprès des gestionnaires responsables de l’implantation du partenariat. Les résultats obtenus révèlent que le contexte organisationnel, le niveau de soutien sociopolitique et la culture organisationnelle des agences de la protection de la jeunesse influencent considérablement l’efficacité du partenariat. Cette étude dresse un portrait des facteurs contribuant à la surreprésentation des enfants Noirs suivis par le système de protection de l’enfance au Canada. Elle suggère que la précarité socioéconomique des familles Noires s'explique partiellement par le traitement différentiel accordé aux dossiers impliquant des enfants Noirs. Elle met également en lumière certains obstacles potentiels à la mise en œuvre des solutions proposées.This three-paper dissertation examines the overrepresentation of Black children reported to child protection services in Canada. The first and second papers examine rates of service disparities using clinical-administrative data provided by a child protection agency for a sample of Black, White, and other visible minority children residing in Montreal, Quebec. Findings from the first paper reveal that compared to White children, Black children’s protection reports were five times more likely to be screened in, substantiated, and brought to court. Black children were also five times more likely than White children to enter out-of-home placement. Findings from the second paper demonstrate disparity in exits from the child protection system through comparison of Black, White and other visible minority children on time spent in out of home placement and likelihood of family reunification. Of these three groups, Black children spent the longest time in out-of-home placement and had a lower proportion of children experiencing family reunification. This decreased likelihood of reunification was statistically associated with three variables: placement instability, age of the child and type of maltreatment. The accessibility of support services within a child’s community to help moderate exposure to risk conditions has been offered as a possible solution in addressing the overrepresentation of Black children. The third paper in this dissertation uses qualitative inquiry employing a thematic approach to highlight some of the challenges faced by a collaboration between a child protection agency and community organization. The creation of the partnership sought to reduce overrepresentation of Black children receiving services from the child protection system. It aimed to improve socioeconomic conditions faced by Black families by providing access to support services to address their needs in a culturally adapted manner. In depth-interviews from members of the stakeholder committee composed of management staff from both the child protection agency and community organization cited challenges pertaining to the child protection agency’s organizational context, level of socio-political support and organizational culture as obstacles to an effective partnership. Together, these three papers document the nature and potential causes of overrepresentation and disparity faced by Black Canadian children. It suggests that the disproportionate need faced by Black families is an important factor explaining their differential treatment within child protection systems. This study also highlights some of the potential barriers in implementing solutions