95 research outputs found
Biogeochemical implications of comparative growth rates of Emiliania huxleyi and Coccolithus species
No full textCoccolithophores, a diverse group of phytoplankton, make important contributions to pelagic calcite production and export, yet the comparative biogeochemical role of species other than the ubiquitous Emiliania huxleyi is poorly understood. The contribution of different coccolithophore species to total calcite production is controlled by inter-species differences in cellular calcite, growth rate and relative abundance within a mixed community. In this study we examined the relative importance of E. huxleyi and two Coccolithus species in terms of daily calcite production. Culture experiments compared growth rates and cellular calcite content of E. huxleyi (Arctic and temperate strains), Coccolithus pelagicus (novel Arctic strain) and Coccolithus braarudii (temperate strain). Despite assumptions that E. huxleyi is a fast-growing species, growth rates between the three species were broadly comparable (0.16–0.85 d?1) under identical temperature and light conditions. Emiliania huxleyi grew only 12% faster on average than C. pelagicus, and 28% faster than C. braarudii. As the cellular calcite content of C. pelagicus and C. braarudii is typically 30–80 times greater than E. huxleyi, comparable growth rates suggest that Coccolithus species have the potential to be major calcite producers in mixed populations. To further explore these results we devised a simplistic model comparing daily calcite production from Coccolithus and E. huxleyi across a realistic range of relative abundances and a wide range of relative growth rates. Using the relative differences in growth rates from our culture studies, we found that C. pelagicus would be a larger source of calcite if abundances of E. huxleyi to C. pelagicus were below 34:1. Relative abundance data collected from North Atlantic field samples (spring and summer 2010) suggest that, with a relative growth rate of 88%, C. pelagicus dominated calcite production at 69% of the sites sampled. With a more extreme difference in growth rates, where C. pelagicus grows at 1/10th of the rate of E. huxleyi, C. pelagicus still dominated calcite production in 14% of the field. These results demonstrate the necessity of considering interactions between inter-species differences in growth rates, cellular calcite and relative abundances when evaluating the contribution of different coccolithophores to pelagic calcite production. In the case of C. pelagicus, we find that there is strong potential for this species to make major contributions to calcite production in the North Atlantic, although estimates of relative growth rates from the field are needed to confirm our conclusions
The Emiliania huxleyi stoichiometry database
No full textThe Emiliania huxleyi stoichiometry database contains data for the growth rate, cellular elemental content (particulate inorganic carbon - PIC, organic carbon - C, nitrogen - N and phosphorous - P) and C:N:P stoichiometry (PIC:C, C:N, N:P, C:P) compiled through a meta-analysis of literature reporting the results of laboratory experiments (cultures) on the coccolithophore species Emiliania huxleyi, an important calcifying marine phytoplankton.
The database also reports selected additional parameters including cell size and/or volume, and chlorophyll a as well as additional meta-data associated with the original data source including strain details and culture experimental conditions. A description of the parameters contained in the database can be found in the file "The Emiliania huxleyi stoichiometry database data description".
Please cite this dataset as:
Sheward et al. (2023) The Emiliania huxleyi stoichiometry database. doi:10.5281/zenodo.7594880The author can be contacted at [email protected] to confirm versioning and to request details of any accompanying publications that arise.
The compilation of this database was supported by Mount Allison University, Canada and Dalhousie University, Canada and funding through the Canada Research Chairs program (ZVF) and the Simons Collaboration on Computational Biogeochemical Modeling of Marine Ecosystems (CBIOMES grants 549937 to ZVF and 549935 to AJI)
Trabajo de investigación: relación que existe entre la realización de actividad fÃsica y el rendimiento académico en los estudiantes de primer y segundo año medio de los Colegios Augusto D'Halmar, Campvs College y San Ignacio El Bosque, durante el año 2016
No full textTrabajo (licenciado en educación) -- Universidad Mayor (Chile), 2016
Higher Education Research in Scotland: Report of a Survey Undertaken by Universities Scotland Educational Development Sub-Committee
No full textThe aim of this study was to gain an insight into a range of higher educational research taking place across Scotland with a particular focus on the nature, expertise, support and dissemination of this research.
For the purposes of this study, we used the term ‘research into higher education’ to refer to a range of higher educational research activity that included: research into higher education policies and practice, pedagogical research, research into learning and teaching taking place in higher education and research about transition from further education or school into higher education.
The findings point to the underground nature of pedagogic research taking place in Scotland. Many researchers are based within disciplines and their pedagogic research is disseminated in a variety of settings that do not always make it easily accessible within generic higher education research discourse. Pedagogic research is also apparently undervalued, with many academic staff experiencing pressure to prioritise publishing within their main discipline over and above pedagogic research. In addition there appears to be a lack of capacity within Scottish institutions to maximise the profile of higher educational research in the forthcoming UK Research Excellence Framework (REF) exercise
The tympanic membrane displacement analyser for monitoring intracranial pressure in children
No full textPurpose: Raised intracranial pressure (ICP) is a potentially treatable cause of morbidity and mortality but tools for monitoring are invasive. We sought to investigate the utility of the tympanic membrane displacement (TMD) analyser for non-invasive measurement of ICP in children.
Methods: We made TMD observations on normal and acutely comatose children presenting to Kilifi District Hospital (KDH) at the rural coast of Kenya and on children on follow-up for idiopathic intracranial hypertension at Evelina Children’s Hospital (ECH), in London, UK.
Results: We recruited 63 patients (median age 3.3 (inter-quartile range (IQR) 2.0–4.3) years) at KDH and 14 children (median age 10 (IQR 5–11) years) at ECH. We observed significantly higher (more negative) TMD measurements in KDH children presenting with coma compared to normal children seen at the hospital’s outpatient department, in both semi-recumbent [mean −61.3 (95 % confidence interval (95 % CI) −93.5 to 29.1) nl versus mean −7.1 (95 % CI −54.0 to 68.3) nl, respectively; P = 0.03] and recumbent postures [mean −61.4 (95 % CI −93.4 to −29.3) nl, n = 59) versus mean −25.9 (95 % CI −71.4 to 123.2) nl, respectively; P = 0.03]. We also observed higher TMD measurements in ECH children with raised ICP measurements, as indicated by lumbar puncture manometry, compared to those with normal ICP, in both semi-recumbent [mean −259.3 (95 % CI −363.8 to −154.8) nl versus mean 26.7 (95 % CI −52.3 to 105.7) nl, respectively; P < 0.01] and recumbent postures [mean −137.5 (95 % CI −260.6 to −14.4) nl versus mean 96.6 (95 % CI 6.5 to 186.6) nl, respectively; P < 0.01].
Conclusion: The TMD analyser has a potential utility in monitoring ICP in a variety of clinical circumstances
EDUBASE - A bibliography of education for Black South Africans
No full textEDUBASE is a database of educational information relating to the field of black education in South Africa, covering the period from the nineteenth century to 1992. The resources curated by the EDUBASE collection including books and book chapters, journal articles, conference papers and presentations, white papers and other forms of governmental and civil society documents. In total, EDUBASE includes nearly 9000 publications on the topic of education for black South Africans. A separate database inspired by EDUBASE focusing specifically on education in the Transkei was produced by David Hiscock, and has been added to this collection. The database was originally located on UCT's servers. Over time, it migrated formats several times, from floppy disks to stiffy disks, then to CD-ROMs, a flashdrive, and finally to cloud-based storage provided here on ZivaHub. The School of Education at UCT kindly allocated space for the project up to 1992, and the physical collection now resides at UCT Libraries Special Collections, as the 'BC1584 Edubase Collection'. This collection consists of the database files in MS Access format (EDUBASE_Kallaway.mdb and EDUBASE_Hiscock_Transkei.mbd), along with a list of keywords in .csv format, and a set of instructions on how to navigate the databases as a PDF. The database itself is searchable by keyword, author or date of publication. Open versions of both databases have also been added in .csv format. The funding for the project was made possible by the authors of Apartheid and Education who agreed to donate their share of the royalties to a fund that was established for this purpose. Various people have worked on the EDUBASE over the years, including Jackie Kallaway, Deirdre Birch, Vera Hulley, David Hiscock and Debbie Sheward. Many thanks to them for making possible the development this invaluable tool for the advancement of research in this important area. Thanks also go to Gary November of the UCT Digitisation unit, who digitised the cover of the original EDUBASE printout; Adrianna Pinska and Corne Oosthuizen for their support in migrating the content from the .mdb files to open .csv spreadsheets. The references fields below contain links to Dr Peter Kallaway’s other publications on education for Black South Africans.<br
Seropositivity in blood donors and pregnant women during the first year of SARS-CoV-2 transmission in Stockholm, Sweden
No full textIn Sweden, social restrictions to contain SARS-CoV-2 have to date primarily relied upon voluntary adherence to a set of recommendations and strict lockdowns/regulations have not been enforced, potentially affecting viral dissemination. To understand the levels of past SARS-CoV-2 infection in the Stockholm population before the start of mass vaccinations, healthy blood donors and pregnant women ( n= 5,100) were sampled at random between 14 th March 2020-28 th February 2021. All individuals ( n= 200/sampling week) were screened for anti-SARS-CoV-2 spike (S) trimer- and RBD-specific IgG responses and the results were compared with those from historical controls ( n= 595). Data were modelled using a probabilistic Bayesian framework that considered individual responses to both viral antigens. We found that after a steep rise at the start of the pandemic, the seroprevalence trajectory increased more steadily (over summer) in approach to the winter second-wave of infections, approaching 15% of all adults surveyed by mid-December 2020. The population seropositivity rate again increased more rapidly as cases rose over the winter period. By the end of February 2021, ∼19% (∼one-in-five) in this study group tested seropositive. Notably, 96% of random seropositive samples screened ( n =56), displayed virus neutralizing responses, with titers comparable to those engendered by recently approved mRNA vaccines, supporting that milder infections generally provoke a competent B cell response. These data offer baseline information about the level of seropositivity in this group of active adults in the Stockholm metropolitan area following a full year of SARS-CoV-2 transmission and prior to the introduction of vaccines. Structured abstract Objectives Sweden did not enforce social lockdown in response to the SARS-CoV-2 pandemic. Therefore, we sought to determine the proportion of seropositive healthy, active adults in Stockholm, the country’s most populous region. Random sampling (of blood donors and pregnant women) was carried out during the first year following virus emergence in the country and prior to vaccination of the general adult population – allowing for an estimate of seroprevalence in response to natural infection. Design In this cross-sectional prospective study, otherwise-healthy blood donors ( n= 2,600) and pregnant women( n= 2,500) were sampled at random for consecutive weeks (at four intervals) between 14 th March and 28 th February 2021. Sera from all participants and a cohort of historical controls ( n= 595) were screened for IgG responses against trimers of the SARS-CoV-2 spike (S) glycoprotein and the smaller receptor-binding domain (RBD). As a complement to standard analytical approaches, a probabilistic (cut-off-independent) Bayesian framework that assigns likelihood of past infection was used to analyze data over time. The study was carried out in accordance with Swedish Ethical Review Authority: registration number 2020-01807. Setting Healthy participant samples were selected from their respective pools at random through Karolinska University Hospital. Participants None of the participants were symptomatic at sampling. No additional metadata was available from the samples. Results Blood donors and pregnant women showed a similar seroprevalence. After a steep rise at the start of the pandemic, the seroprevalence trajectory increased steadily in approach to the winter second-wave of infections, approaching 15% of all individuals surveyed by 13 th December 2020. By the end of February 2021, when deaths were in decline and at low levels following their winter peak, 19% of the population tested seropositive. Notably, 96% of seropositive healthy donors screened ( n= 56) developed neutralizing antibody responses at titers comparable to, or higher than those observed in clinical trials of SARS-CoV-2 spike mRNA vaccination, supporting that mild infection engenders a competent B cell response. Conclusions These data indicate that in the year since the start of community transmission, seropositivity levels in metropolitan Stockholm had reached approximately one-in-five persons, providing important baseline seroprevalence information prior to the start of vaccination
Effects of osteopathy on hand function, disease symptoms and functional status in female workers with systemic sclerosis: a series of single case studies.
No full textRésumé : Dans la sclérodermie systémique (ScS), les contractures aux mains, pour lesquelles il n'existe aucun traitement prouvé, sont courantes et associées à de l'incapacité de la main, globale et au travail. Toutefois, quelques études sur les effets d'interventions comprenant des techniques manuelles ont montré des résultats prometteurs. Ainsi, le but de l'étude était d'explorer les effets d’un traitement ostéopathique sur la fonction de la main, des symptômes globaux de la maladie et le statut fonctionnel de personnes atteintes de ScS. Une série d'études à cas uniques (A[indice inférieur 1]-B-A[indice inférieur 2]) fut réalisée. Six participantes atteintes de ScS ont été recrutées parmi la cohorte du Groupe de recherche canadien sur la sclérodermie à deux sites (Hôpital général juif de Montréal et Centre hospitalier universitaire de Sherbrooke). Les participantes ont reçu neuf séances hebdomadaires d’ostéopathie semi-standardisées, ciblées sur les membres supérieurs, le thorax et la base du crâne. Des mesures répétées pendant les trois phases de l'étude ont été prises à une fréquence bihebdomadaire pour la raideur aux mains (RM) et les symptômes de douleur, dyspnée et fatigue; et hebdomadaire pour l'amplitude de mouvement des doigts (AMD), la fonction de la main (FM) et l'incapacité globale (IG). L'épaisseur/rigidité de la peau main/avant-bras (ÉPMA), l'incapacité au travail (IT) et la qualité de vie reliée à la santé (QVS) ont été mesurées à trois temps (avant et après l'intervention, ainsi qu'au suivi à un mois). Les variables à mesures répétées ont été représentées sur des graphiques linéaires soumis à des analyses visuelles, complétées du test Sheward's two Standard Deviation Band. Les différences ont été calculées pour les variables mesurées à trois temps. Toutes les participantes (n=6) ont montré une amélioration des variables reliées à la fonction manuelle (RM, AMD et FM), sauf pour l'ÉPMA (n=4). La majorité des participantes ont montré une amélioration des symptômes (douleur n=6, fatigue n=4 et dyspnée n=3/4) et des variables reliées au statut fonctionnel (IG n=5/5, IT n=4, score résumé physique n=6 et mental n=4 de la QVS). La plupart des effets se sont maintenus au suivi à un mois. Lorsque la comparaison était possible, presque toutes les améliorations observées ont été supérieures aux différences minimales cliniquement importantes suggérées pour cette population. Ces résultats suggèrent que l'ostéopathie pourrait être efficace pour réduire l'incapacité découlant des contractures aux mains de personnes souffrant de ScS, et devraient être vérifiés dans un essai clinique randomisé. // Abstract : In systemic sclerosis (SSc), hand contractures are common and associated with hand, global and work disability. There are no known effective treatments, although there have been a few promising studies with manual therapies. Our aim was to explore the effects of osteopathy on hand function, disease symptoms and functional status in SSc patients. A series of single case studies (A[subscript 1]-B-A[subscript 2] was undertaken. Six female SSc patients with hand contractures were recruited among subjects enrolled in the Canadian Scleroderma Research Group cohort at 2 sites (Jewish General Hospital, Montreal and Centre hospitalier universitaire de Sherbrooke, Sherbrooke). Participants received 9 weekly semi-standardized sessions of osteopathy targetted on upper limbs, thorax and cranial base. Repeated measures were taken during the three phases of the study, twice a week for hand stiffness and disease symptoms of pain, dyspnea and fatigue; and once a week for range of motion of fingers, hand disability and global disability. Upper limbs skin score, work disability and health-related quality of life were measured at baseline, after treatments and at 1-month follow-up. Data for each variable with repeated measures were represented on simple line graphs and visually interpreted, completed by the Sheward's two Standard Deviation Band test. Differences were calculated for variables measured at 3 time points. All participants (n=6) showed improvement in variables related to hand function (hand stiffness, range of motion of fingers and hand disability), except for upper limbs skin score (n=4). The majority of participants showed improvement in disease symptoms (pain n=6, fatigue n=4, et dyspnea n=3/4) as well as variables related to functional status (global disability n=5/5, work disability n=4, physical n=6 and mental n=4 component summary of health-related quality of life). Most improvements were maintained at 4 week follow up. When the comparison was possible, almost all observed improvements were higher than the minimal clinically important differences suggested for this population. These findings suggest that osteopathy may be effective in reducing disability from hand contractures in SSc. A randomized controlled trial is needed to confirm these results
Celsr1, a neural-specific gene encoding an unusual seven-pass transmembrane receptor, maps to mouse chromosome 15 and human chromosome 22qter
No full textWe have identified Celsr1, a gene that encodes a developmentally regulated vertebrate seven-pass transmembrane protein. The extracellular domain of Celsr1 contains two regions each with homology to distinct classes of well-characterized motifs found in the extra-cellular domains of many cell surface molecules. The most N-terminal region contains a block of contiguous cadherin repeats, and C-terminal to this is a region containing seven epidermal growth factor-like repeats interrupted by two laminin A G-type repeats. Celsr1 is unique in that it contains this combination of repeats coupled to a seven-pass transmembrane domain. As part of the characterization of the Celsr1 gene, we have determined its chromosomal map location in both mouse and human. The European Collaborative Interspecific Backcross (EUCIB) and BXD recombinant inbred strains were used for mapping Celsr1 cDNA clones in the mouse, and fluorescence in situ hybridization was used to map human Celsr1 cosmid clones on metaphase chromosomes. We report that Celsr1 maps to proximal mouse Chromosome 15 and human chromosome 22qter, a region of conserved synteny. Reverse transcriptase-polymerase chain reaction analysis and in situ hybridization were used to determine the spatial restriction of Celsr1 transcripts in adult and embryonic mice. The results presented here extend our previous finding of expression of the Celsr1 receptor in the embryo and show that expression continues into adult life when expression in the brain is localized principally in the ependymal cell layer, choroid plexus, and the area postrem
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