Determining adsorbate configuration on alumina surfaces with 13C nuclear magnetic resonance relaxation time analysis

Relative strengths of surface interaction for individual carbon atoms in acyclic and cyclic hydrocarbons adsorbed on alumina surfaces are determined using chemically resolved 13C nuclear magnetic resonance (NMR) T1 relaxation times. The ratio of relaxation times for the adsorbed atoms T1,ads to the bulk liquid relaxation time T1,bulk provides an indication of the mobility of the atom. Hence a low T1,ads/T1,bulk ratio indicates a stronger surface interaction. The carbon atoms associated with unsaturated bonds in the molecules are seen to exhibit a larger reduction in T1 on adsorption relative to the aliphatic carbons, consistent with adsorption occurring through the carbon-carbon multiple bonds. The relaxation data are interpreted in terms of proximity of individual carbon atoms to the alumina surface and adsorption conformations are inferred. Furthermore, variations of interaction strength and molecular configuration have been explored as a function of adsorbate coverage, temperature, surface pre-treatment, and in the presence of co-adsorbates. This relaxation time analysis is appropriate for studying the behaviour of hydrocarbons adsorbed on a wide range of catalyst support and supported-metal catalyst surfaces, and offers the potential to explore such systems under realistic operating conditions when multiple chemical components are present at the surface.

Marrow aplasia developing 13 years after HLA-identical sibling allogeneic transplantation for chronic myeloid leukaemia:successful treatment with antithymocyte globulin and peripheral blood stem cell infusion from the original donor

Secondary or late graft failure has been defined as the development of inadequate marrow function after initial engraftment has been achieved. We describe a case of profound marrow aplasia occurring 13 years after sibling allogeneic bone marrow transplantation for chronic myeloid leukaemia (CML) in first chronic phase. Although the patient remained a complete donor chimera, thereby suggesting that an unselected infusion of donor peripheral blood stem cells (PBSC) or bone marrow might be indicated, the newly acquired aplasia was thought to be immune in aetiology and some immunosuppression was therefore considered appropriate. Rapid haematological recovery was achieved after the infusion of unselected PBSC from the original donor following conditioning with anti-thymocyte globulin (ATG).

Balancing the (carbon) budget: Using linear inverse models to estimate carbon flows and mass-balance 13C:15N labelling experiments in low oxygen sediments.

Over 1 million km² of seafloor experience permanent low-oxygen conditions within oxygen minimum zones (OMZs). OMZs are predicted to grow as a consequence of climate change, potentially affecting oceanic biogeochemical cycles. The Arabian Sea OMZ impinges upon the western Indian continental margin at bathyal depths (150 - 1500 m) producing a strong depth dependent oxygen gradient at the sea floor. The influence of the OMZ upon the short term processing of organic matter by sediment ecosystems was investigated using in situ stable isotope pulse chase experiments. These deployed doses of ¹³C:¹⁵N labeled organic matter onto the sediment surface at four stations from across the OMZ (water depth 540 - 1100 m; [O₂] = 0.35 - 15 μM). In order to prevent experimentally anoxia, the mesocosms were not sealed. ¹³C and ¹⁵N labels were traced into sediment, bacteria, fauna and ¹³C into sediment porewater DIC and DOC. However, the DIC and DOC flux to the water column could not be measured, limiting our capacity to obtain mass-balance for C in each experimental mesocosm. Linear Inverse Modeling (LIM) provides a method to obtain a mass-balanced model of carbon flow that integrates stable-isotope tracer data with community biomass and biogeochemical flux data from a range of sources. Here we present an adaptation of the LIM methodology used to investigate how ecosystem structure influenced carbon flow across the Indian margin OMZ. We demonstrate how oxygen conditions affect food-web complexity, affecting the linkages between the bacteria, foraminifera and metazoan fauna, and their contributions to benthic respiration. The food-web models demonstrate how changes in ecosystem complexity are associated with oxygen availability across the OMZ and allow us to obtain a complete carbon budget for the stationa where stable-isotope labelling experiments were conducted.

Responsiveness of dark-adaptation threshold to vitamin A and beta-carotene supplementation in pregnant and lactating women in Nepal.

BACKGROUND: Impaired dark adaptation occurs commonly in vitamin A deficiency. OBJECTIVE: We sought to examine the responsiveness of dark-adaptation threshold to vitamin A and beta-carotene supplementation in Nepali women. DESIGN: The dark-adapted pupillary response was tested in 298 pregnant women aged 15-45 y in a placebo-controlled trial of vitamin A and beta-carotene; 131 of these women were also tested at 3 mo postpartum. Results were compared with those for 100 nonpregnant US women of similar age. The amount of light required for pupillary constriction was recorded after bleaching and dark adaptation. RESULTS: Pregnant women receiving vitamin A had better dark-adaptation thresholds (-1.24 log cd/m(2)) than did those receiving placebo (-1.11 log cd/m(2); P: = 0. 03) or beta-carotene (-1.13 log cd/m(2); P: = 0.05) (t tests with Bonferroni correction). Dark-adaptation threshold was associated with serum retinol concentration in pregnant women receiving placebo (P: = 0.001) and in those receiving beta-carotene (P: = 0.003) but not in those receiving vitamin A. Among women receiving placebo, mean dark-adaptation thresholds were better during the first trimester (-1.23 log cd/m(2)) than during the second and third trimesters (-1.03 log cd/m(2); P: = 0.02, t test). The mean threshold of nonpregnant US women (-1.35 log cd/m(2)) was better than that of all 3 Nepali groups (P: < 0.001, t test, for all 3 groups). CONCLUSIONS: During pregnancy, pupillary dark adaptation was strongly associated with serum retinol concentration and improved significantly in response to vitamin A supplementation. This noninvasive testing technique is a valid indicator of population vitamin A status in women of reproductive age.

Mundo Shuar 13: La muerte y los entierros

La manera con que un hombre (o un pueblo) mira a la muerte no revela solamente su manera de entender Ia vida, sino su visión total de los valores espirituales. Las tumbas nos dicen cuan difícilmente los seres humaruts se resignan a desaparecer. Algunas de las obras mós imponentes que nos han legado los siglos son monumentos sepulcrales, como las piramides de Egipto. Una civilización tan refinada como Ia de los Etruscos nos ha dejado casi exclusivamente restos de arte funerario. Se sabe que los Incas habían logrado procedimientos muy complejos para momificar y conservar a sus muertos...

Prevention of falls in the elderly in the home: promoting active ageing

Objective: To determine the frequency of falls and identify risk factors in the homes of the elderly under the Home Care Service of a village in Alentejo (Portugal). Method: Exploratory, descriptive study. The target group were elderly persons under the Home Care Service (23). The questionnaire consists of open and closed questions, and was based on the Jefferson Area Board for Aging Safety in the Home Assessment; Instrument to Assess the Risk of Falls and Adaptations to Prevent Falls at Home. Results: Of the 23 seniors, 13 were men; the mean age was 85; 10 widowers; 11 live alone; 12 cannot read or write; 17 have experienced falls, loss of balance being the main cause. They report changes in vision (21), hearing (14) and rheumatic diseases (14); hypertension (19); they use 4 or more drugs on a daily basis (16). Conclusion: The physiological changes associated with ageing may increase the risk of falls. Due to the consequences, it is a priority field in community intervention.

Prevention of falls in the elderly in the home: promoting active ageing

To determine the frequency of falls and identify risk factors in the homes of the elderly under the Home Care Service of a village in Alentejo (Portugal). Method: Exploratory, descriptive study. The target group were elderly persons under the Home Care Service (23). The questionnaire consists of open and closed questions, and was based on the Jefferson Area Board for Aging Safety in the Home Assessment; Instrument to Assess the Risk of Falls and Adaptations to Prevent Falls at Home. Results: Of the 23 seniors, 13 were men; the mean age was 85; 10 widowers; 11 live alone; 12 cannot read or write; 17 have experienced falls, loss of balance being the main cause. They report changes in vision (21), hearing (14) and rheumatic diseases (14); hypertension (19); they use 4 or more drugs on a daily basis (16). Conclusion: The physiological changes associated with ageing may increase the risk of falls. Due to the consequences, it is a priority field in community intervention.

A produção de texto escrito criativo no contexto de sala de aula : o caso dos alunos de 12/13 anos

O trabalho que se segue estuda a natureza dos textos “criativos” produzidos por alunos de 12/13 anos, em situação de sala de aula. Para o efeito seleccionámos duas turmas do Ensino Básico – 3º ciclo – de perfis diferentes e acompanhámos os sessenta alunos que se enquadravam nessa faixa etária durante um ano lectivo, seguindo a sua evolução. Centrámos o nosso estudo no aluno, como produtor do texto, preocupado em fazer o seu melhor, desenvolvendo os temas a tratar com a originalidade de que era capaz e procurando a forma adequada ao assunto e à situação. Verificámos a sua preocupação em cumprir as expectativas do professor/receptor, mas também a sua vontade de entrar em negociações, numa tentativa de integrar as expectativas do docente nos seus próprios interesses pessoais. Para a sistematização das características globais dos textos produzidos pelos alunos utilizámos o modelo de análise textual de Beaugrande & Dressler, por nos parecer adaptar-se à situação de diálogo escolar, subjacente a qualquer produção de texto em sala de aula. O levantamento das características globais dos textos dos alunos tornou evidente as suas diferenças e os seus traços de individualidade. Por isso, achámos que este estudo não estaria completo sem a complementação duma segunda parte em que procurássemos encontrar os traços estilísticos desses mesmos textos, numa tentativa de analisar a presença de algumas características de estilo colectivas, produto das preocupações comuns aos alunos, assim como alguns traços estilísticos individuais, consequência de vivências particulares. Terminaremos fazendo uma síntese dos dados obtidos e reflectindo sobre as suas implicações na situação de ensino/aprendizagem.

Les Cahiers Anne Hébert, 13 : Legs d'Anne Hébert : Lecture, intertextualité, transmission

La critique a depuis longtemps identifié les lieux de lecture travaillés par les œuvres hébertiennes, de la Bible à Faulkner en passant par Chrétien de Troyes et les contes de fées. Mais si la lecture est un legs, un témoignage du passé qu’il est loisible d’interroger dans le présent de l’écriture, les œuvres d’Anne Hébert – l’adaptation cinématographique du Torrent en est l’illustration éclatante – constituent désormais un héritage dont les effets peuvent être analysés. Nous voudrions ici interroger ces deux modalités du legs d’Anne Hébert en nous attachant aussi bien aux traces des lectures de l’écrivaine qui parsèment son œuvre qu’à ce que cette dernière a légué en retour aux écrivains, ou cinéastes, qui lui succèdent. La présence de la bibliothèque de l’écrivaine au Centre Anne-Hébert est à cet égard à même d’ouvrir de nouvelles avenues de recherche, susceptibles de renouveler notre compréhension des œuvres. Ce n’est donc pas seulement d’intertextualité qu’il est question dans ces pages, ni de la notion ambigüe d’influence qu’elle était venue remplacer, mais bien de ce legs symbolique bien particulier que constitue la lecture. À quel héritage littéraire Anne Hébert a-t-elle puisé afin de rompre avec les discours social et littéraire du Canada français des années 1940? Quel traitement réserve-t-elle à l’héritage canadien-français, notamment religieux? Mais aussi, qu’en est-il, dans son œuvre, de cet enjeu majeur de la transmission, elle qui ne cesse de s’interroger, d’un texte à l’autre, sur les effets ineffaçables du passé à partir de son refoulement? Voilà quelques-unes des questions qui ont retenu l’attention des auteur(e)s de ce dossier, qui souhaite ainsi participer au renouvellement de la recherche sur cet aspect primordial du legs.