1,029 research outputs found
The summertime plankton community at South Georgia (Southern Ocean): comparing the historical (1926/27) and modern (post 1995) records.
The earliest comprehensive plankton sampling programme in the Southern Ocean was 32 undertaken during the early part of last century by Discovery Investigations to gain a 33 greater scientific understanding of whale stocks and their summer feeding grounds. An 34 initial survey was carried out around South Georgia during December 1926 and January 35 1927 to describe the distribution of plankton during the summer, and to serve as a 36 baseline against which to compare future surveys. We have reanalysed phytoplankton and 37 zooplankton data from this survey and elucidated patterns of community distribution and 38 compared them with our recent understanding of the ecosystem based on contemporary 39 data. Analysis of Discovery data identified five groups of stations with characteristic 40 phytoplankton communities which were almost entirely consistent with the original 41 analysis conducted by Hardy and Gunther (1935). Major groupings were located at the 42 western end of the island and over the northern shelf where Corethron spp. were 43 dominant, and to the south and east where a more diverse flora included high abundances 44 of Nitzschia seriata. Major zooplankton-station groupings were located over the inner 45 shelf which was characterised by a high abundance of Drepanopus forcipatus and in 46 oceanic water >500 m deep that were dominated by Foraminifera, Oithona spp., 47 Ctenocalanus vanus, and Calanoides acutus. Stations along the middle and outer shelf 48 regions to the north and west, were characterised by low overall abundance. There was 49 some evidence that groupings of stations to the north of the island originated in different 50 water masses on either side of the Southern Antarctic Circumpolar Current Front, the 51 major frontal system in the deep ocean close to South Georgia. However, transect lines 52 during 1926/27 did not extend far enough offshore to sample this frontal region 53
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adequately. Interannual variability of zooplankton abundance was assessed from stations 54 which were sampled repeatedly during 7 recent British Antarctic Survey cruises (1995-55 2005) to the region and following taxonomic harmonization and numerical 56 standardization (ind. m-3), a subset of 45 taxonomic categories of zooplankton (species 57 and higher taxa) from 1926/27, were compared with similar data obtained during the 58 BAS cruises using a linear model. Initially comparisons were restricted to BAS stations 59 that lay within 40 km of Discovery stations although a comparison was also made using 60 all available data. Despite low abundance values in 1926/27, in neither comparison did 61 Discovery data differ significantly from BAS data. Calculation of the percentage 62 similarity index across cruises did not reveal any systematic differences in species 63 composition between 1926/27 and the present. In the light of ocean warming trends, the 64 existence of more subtle changes in species composition is not ruled out, but an absence 65 of finely resolved time-series data make this impossible to determine
Development and validation of the Brazilian version of the Attitudes to Aging Questionnaire (AAQ): An example of merging classical psychometric theory and the Rasch measurement model
Aging has determined a demographic shift in the world, which is considered a major societal achievement, and a challenge. Aging is primarily a subjective experience, shaped by factors such as gender and culture. There is a lack of instruments to assess attitudes to aging adequately. In addition, there is no instrument developed or validated in developing region contexts, so that the particularities of ageing in these areas are not included in the measures available. This paper aims to develop and validate a reliable attitude to aging instrument by combining classical psychometric approach and Rasch analysis
The EUROHIS-QOL 8-Item Index: Comparative Psychometric Properties to Its Parent WHOQOL-BREF
AbstractObjectivesTo test the psychometric properties of the EUROHIS-QOL 8-item index, a shortened version of the World Health Organization Quality of Life Instrument-Abbreviated Version (WHOQOL-BREF).MethodsThe sample consisted of 2359 subjects identified from primary care settings, with 1193 having a confirmed diagnosis of depression. Data came from six countries (Australia, Brazil, Israel, Russia, Spain, and the United States) involved in a large international study, the Longitudinal Investigation of Depression Outcomes. The structure of the EUROHIS-QOL 8-item index follows that of the WHOQOL-BREF assessment. Internal consistency was measured by using Cronbach's alpha. Convergent validity was assessed by using correlations with different measures for mental health (Symptom Checklist 90), physical health (self-evaluation), and quality of life (WHOQOL-BREF and short form 36 health survey). Discriminant group validity was assessed between diagnosed depressed and nondepressed patients. Differential item functioning and unidimensionality were analyzed by using Rasch analysis. Factor structure was assessed with structural equation modeling analyses.ResultsInternal consistency was acceptable (ranged between 0.72 and 0.81 across countries), and the index discriminated well between depression (t = 6.31â20.33; P < 0.001) across all countries. Correlations between the EUROHIS-QOL 8-item index and different measuresâSymptom Checklist 90 (r = â0.42), physical health (r = â0.42), WHOQOL-BREF domains (r = 0.61â0.77), and short form 36 health survey (r = 0.58)âwere all significant (P < 0.001). The index is unidimensional with desired item fit statistics. Two items (âdaily living activitiesâ and âenough money to meet your needsâ) had residuals exceeding 4. Differential item functioning was observed with general quality of life, general health, relationships, and home items for age. A common one-factor structure with acceptable fit was identified in three out of six countries (comparative fit index = 0.85, root mean square error of approximation = 0.11).ConclusionsThe EUROHIS-QOL 8-item index showed acceptable cross-cultural performance and a satisfactory discriminant validity and would be a useful measure to include in studies to assess treatment effectiveness
Modelling and upscaling of transport in carbonates during dissolution: validation and calibration with NMR experiments
We present an experimental and numerical study of transport in carbonates during dissolution and its upscaling from the pore (⌠Όm) to core (⌠cm) scale. For the experimental part, we use nuclear magnetic resonance (NMR) to probe molecular displacements (propagators) of an aqueous hydrochloric acid (HCl) solution through a Ketton limestone core. A series of propagator profiles are obtained at a large number of spatial points along the core at multiple time-steps during dissolution. For the numerical part, first, the transport modelâa particle-tracking method based on Continuous Time Random Walks (CTRW) by Rhodes et al. (2008)âis validated at the pore scale by matching to the NMR-measured propagators in a beadpack, Bentheimer sandstone, and Portland carbonate Scheven et al. (2005). It was found that the emerging distribution of particle transit times in these samples can be approximated satisfactorily using the power law function Ï(t) ⌠t â1 âÎČ, where 0 < ÎČ < 2. Next, the evolution of the propagators during reaction is modelled: at the pore scale, the experimental data is used to calibrate the CTRW parameters; then the shape of the propagators is predicted at later observation times. Finally, a numerical upscaling technique is employed to obtain CTRW parameters for the core. From the NMR-measured propagators, an increasing frequency of displacements in stagnant regions was apparent as the reaction progressed. The present model predicts that non-Fickian behaviour exhibited at the pore scale persists on the centimetre scale
Neural correlates of executive function and working memory in the 'at risk mental state'
Background and Aims: People with âprodromalâ symptoms have a very high risk of developing psychosis. We used functional MRI to examine the neurocognitive basis of this vulnerability.
Method: Cross-sectional comparison of subjects with an ARMS (n=17), first episode schizophreniform psychosis (n=10) and healthy volunteers (n=15). Subjects were studied using functional MRI while they performed an overt verbal fluency task, a random movement generation paradigm and an N-Back working memory task.
Results: During an N-Back task the ARMS group engaged inferior frontal and posterior parietal cortex less than controls but more than the first episode group. During a motor generation task, the ARMS group showed less activation in the left inferior parietal cortex than controls, but greater activation than the first episode group. During verbal fluency using âEasyâ letters, the ARMS group demonstrated intermediate activation in the left inferior frontal cortex, with first episode groups showing least, and controls most, activation. When processing âHardâ letters, differential activation was evident in two left inferior frontal regions. In its dorsolateral portion, the ARMS group showed less activation than controls but more than the first episode group, while in the opercular part of the left inferior frontal gyrus / anterior insula activation was greatest in the first episode group, weakest in controls and intermediate in the ARMS group.
Conclusions: The ARMS is associated with abnormalities of regional brain function that are qualitatively similar to those in patients who have just developed psychosis but less severe
Microwave pyrolysis of Laminaria digitata to produce unique seaweed-derived bio-oils
Microwave pyrolysis has become an attractive form of processing technology to generate bio-oil, bio-char and syngas from different biomass feedstocks. In this study, microwave pyrolysis was performed on the UK native seaweed Laminaria digitata and its extract residue from a bio-refinery process. Pyrolysis of these two feedstocks was successfully achieved without the requirement of microwave susceptors, as pelletizing the biomass was sufficient to allow microwave pyrolysis to occur. It was found that average energy requirements as low as 1.84â2.83âŻkJâŻgâ1 were required to pyrolyse 55â70% of both feedstocks and bio-oil yields of 5â8% and 10â14% for native and extraction residue L. digitata were produced, respectively. Maximum microwave pyrolysis processing times were in the order of 200âŻs. The bio-oil generated from both feedstocks contained no phenolic based compounds, but a greater number of nitrogen-containing compounds and compounds derived from macroalgal polysaccharides. Yields of certain compounds differed in bio-oils generated from the two L. digitata feedstocks, however it was observed that specific energy did not have a direct influence on bio-oil compound yield. Furthermore, the identification of a particular nitrogen-containing compound L-Proline, 1-methyl-5-oxo-, methylester is thought to be a unique product of microwave pyrolysis when carbon-based additives are avoided
The role of perceived benefits and costs in patientsâ medical decisions
Backgroundâ Many decisions can be understood in terms of actorsâ valuations of benefits and costs. The article investigates whether this is also true of patient medical decision making. It aims to investigate (i) the importance patients attach to various reasons for and against nine medical decisions; (ii) how well the importance attached to benefits and costs predicts action or inaction; and (iii) how such valuations are related to decision confidence. Methodsâ In a national random digit dial telephone survey of U.S. adults, patients rated the importance of various reasons for and against medical decisions they had made or talked to a healthâcare provider about during the past 2âyears. Participants were 2575 Englishâspeaking adults age 40 and older. Data were analysed by means of logistic regressions predicting action/inaction and linear regressions predicting confidence. Resultsâ Aggregating individual reasons into those that may be regarded as benefits and those that may be regarded as costs, and weighting them by their importance to the patient, shows the expected relationship to action. Perceived benefits and costs are also significantly related to the confidence patients report about their decision. Conclusionâ The factors patients say are important in their medical decisions reflect a subjective weighing of benefits and costs and predict action/inaction although they do not necessarily indicate that patients are well informed. The greater the difference between the importance attached to benefits and costs, the greater patientsâ confidence in their decision.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/102701/1/hex739.pd
Motivation as a predictor of outcomes in school-based humanistic counselling
Recent years have seen a growth in the provision of counselling within UK secondary schools, and research indicates that it is associated with significant reductions in psychological distress. However, little is known about the moderators and mediators of positive therapeutic benefit. In the field of adult mental health, motivation has been found to be one of the strongest predictors of therapeutic outcomes, and it was hypothesised that this may also be a predictor of outcomes for young people in school-based counselling services. To assess the relationship between young peopleâs motivation for counselling and its effectiveness within a secondary school setting. Eighty-one young people (12 - 17 years old) who attended school-based humanistic counselling services in Scotland. Clients completed a measure of motivation for counselling at the commencement of their therapeutic work and a measure of psychological wellbeing at the commencement and termination of counselling. Motivation for counselling was not found to be significantly related to outcomes. The results indicate that the association between motivation and outcomes may be weaker in young people as compared with adults. However, a number of design factors may also account for the non-significant findings: insufficient participants, marginal reliability of the motivation measure and social desirability effects
Identification of Bio-oil Compound Utilizing Yeasts Through Phenotypic Microarray Screening
© 2019, The Author(s). Abstract: Biomass pyrolysis bio-oil contains a plethora of carbon sources with the potential to be utilized by microorganisms and converted into high value products. However, the majority of these compounds are either highly toxic to microorganisms or are not directly utilizable. Hence research is required to develop methods of separating microbe friendly compounds from inhibitory ones, and to also identify novel microorganisms that can utilise the principal carbon sources in pyrolysis bio-oil. This study employed a phenotypic microarray (PM) technique that measured yeast metabolic output to screen for and shortlist yeast strains able to metabolize various bio-oil carbon sources, with a focus on the anhydrosugar levoglucosan. Four strains of yeast (two Pichia spp. and two Kluyveromyces spp.) were shortlisted due to their high metabolic output (between 79.7 and 113.7 redox signal intensity) on levoglucosan from the PM assay. Under anaerobic fermentation conditions the strains were able to uptake levoglucosan (between 79 and 100% uptake efficiency) but not produce bioethanol; yet trace amounts of acetic acid were generated. This study demonstrated the application of applying the PM technique to screen for novel yeast strains with abilities to metabolize compounds present in pyrolysis bio-oil that could lead to the identification of novel levoglucosan utilization pathways. Graphical Abstract: [Figure not available: see fulltext.]
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