2,129 research outputs found
Variation in the distribution of Antarctic krill Euphausia superba around South Georgia
There is considerable spatial structure within the South Georgia krill-based ecosystem in terms of predator demand, commercial fishery pressure and krill abundance. Here we investigate the hypothesis that there is also spatial structure in the krill population composition, finding differences in length-frequency histograms between the eastern and western ends of the island. Between 1981 and 1997 the British Antarctic Survey carried out 6 major cruises where krill were taken from both ends of South Georgia. Cluster analysis revealed that the length-frequency histograms could be grouped into 4 main types with relatively simple biological characteristics: Cluster 1 contained small krill (mean size 23.9 mm) up to 2 yr old (1+ yr class); Cluster 2 (mean size 31.1 mm) contained a mixture of 1+ with some 2+ and 3+ yr classes; Cluster 3 contained medium-sized krill (mean size 41.4 mm) probably 2+ and 3+ yr classes; Cluster 4 contained large krill (mean size 50.3 mm) likely to be 3+ or older. Principal components analysis (PCA) provided good separation of these clusters using the first 2 axes (80% of the total variance). There were no obvious differences in the length composition of krill sampled from different water depths, although there were some indications that differences did occur between different water masses. Detailed inspection of the individual cruises revealed that the length-frequency histograms at the western end of the island contained more large krill than those from the eastern end of the island and also that when Weddell Sea water was found within a cruise then this contained the smallest krill. We consider that such differences may arise not only because krill may experience different conditions at each end of the island but also may originate from 2 separate sources which may have different population structures
Pseudorehearsal in value function approximation
Catastrophic forgetting is of special importance in reinforcement learning,
as the data distribution is generally non-stationary over time. We study and
compare several pseudorehearsal approaches for Q-learning with function
approximation in a pole balancing task. We have found that pseudorehearsal
seems to assist learning even in such very simple problems, given proper
initialization of the rehearsal parameters
Sustainable product design education: current practice
Current production and consumption patterns are unsustainable, causing irreversible damage to the environment and human health and well-being. Designers play a vital role in resolving this problem their decisions affect product manufacturing, distribution, use, and disposal and hence they must be aware of the positive and negative impacts of their design deci-sions. Sustainable product design education is key to developing the knowl-edge, skills, and responsibility required for future generations of product designers and their educators to make informed and responsible decisions within their practice, and also enhance the social and environmental per-formance of their creations and effectively communicate the value of such decisions within a commercial context. In this article, we present insights and challenges in contemporary sustainable product design education in higher education. We document the experiences of six academics involved in teaching and researching sustainable product design in the United Kingdom, Australia, Denmark, the Netherlands, and the United States. We hope to provide a useful reference for academics seeking to adopt sustainable product design practices in their existing programs, develop new sustainable product design education programs, or reflect on their own existing product design practice
The complete sequences and gene organisation of the mitochondrial genomes of the heterodont bivalves Acanthocardia tuberculata and Hiatella arctica â and the first record for a putative Atpase subunit 8 gene in marine bivalves
BACKGROUND: Mitochondrial (mt) gene arrangement is highly variable among molluscs and especially among bivalves. Of the 30 complete molluscan mt-genomes published to date, only one is of a heterodont bivalve, although this is the most diverse taxon in terms of species numbers. We determined the complete sequence of the mitochondrial genomes of Acanthocardia tuberculata and Hiatella arctica, (Mollusca, Bivalvia, Heterodonta) and describe their gene contents and genome organisations to assess the variability of these features among the Bivalvia and their value for phylogenetic inference. RESULTS: The size of the mt-genome in Acanthocardia tuberculata is 16.104 basepairs (bp), and in Hiatella arctica 18.244 bp. The Acanthocardia mt-genome contains 12 of the typical protein coding genes, lacking the Atpase subunit 8 (atp8) gene, as all published marine bivalves. In contrast, a complete atp8 gene is present in Hiatella arctica. In addition, we found a putative truncated atp8 gene when re-annotating the mt-genome of Venerupis philippinarum. Both mt-genomes reported here encode all genes on the same strand and have an additional trnM. In Acanthocardia several large non-coding regions are present. One of these contains 3.5 nearly identical copies of a 167 bp motive. In Hiatella, the 3' end of the NADH dehydrogenase subunit (nad)6 gene is duplicated together with the adjacent non-coding region. The gene arrangement of Hiatella is markedly different from all other known molluscan mt-genomes, that of Acanthocardia shows few identities with the Venerupis philippinarum. Phylogenetic analyses on amino acid and nucleotide levels robustly support the Heterodonta and the sister group relationship of Acanthocardia and Venerupis. Monophyletic Bivalvia are resolved only by a Bayesian inference of the nucleotide data set. In all other analyses the two unionid species, being to only ones with genes located on both strands, do not group with the remaining bivalves. CONCLUSION: The two mt-genomes reported here add to and underline the high variability of gene order and presence of duplications in bivalve and molluscan taxa. Some genomic traits like the loss of the atp8 gene or the encoding of all genes on the same strand are homoplastic among the Bivalvia. These characters, gene order, and the nucleotide sequence data show considerable potential of resolving phylogenetic patterns at lower taxonomic levels
Reliability of goniometric measurements in children with cerebral palsy: A comparative analysis of universal goniometer and electronic inclinometer. A pilot study
<p>Abstract</p> <p>Background</p> <p>Even though technological progress has provided us with more and more sophisticated equipment for making goniometric measurements, the most commonly used clinical tools are still the universal goniometer and, to a lesser extent, the inclinometer. There is, however, no published study so far that uses an inclinometer for measurements in children with cerebral palsy (CP). The objective of this study was two-fold: to independently assess the intra and inter-examiner reliability for measuring the hip abduction range of motion in children with CP using two different instruments, the universal two-axis goniometer and electronic inclinometer. A pool of 5 examiners with different levels of experience as paediatric physiotherapists participated. The study did not compare both instruments because the measurement procedure and the hip position were different for each.</p> <p>Methods</p> <p>A prospective, observational study of goniometery was carried out with 14 lower extremities of 7 children with spastic CP. The inclinometer study was carried out with 8 lower extremities of 4 children with spastic CP. This study was divided into two independent parts: a study of the reliability of the hip abduction range of motion measured with a universal goniometer (hip at 0° flexion) and with an electronic inclinometer (hip at 90° flexion). The Intraclass Correlation Coefficient (ICC) was calculated to analyse intra and inter-examiner agreement for each instrument.</p> <p>Results</p> <p>For the goniometer, the intra-examiner reliability was excellent (>0.80), while the inter-examiner reliability was low (0.375 and 0.475). For the inclinometer, both the intra-examiner (0.850-0.975) and inter-examiner reliability were excellent (0.965 and 0.979).</p> <p>Conclusions</p> <p>The inter-examiner reliability for goniometric measurement of hip abduction in children with CP was low, in keeping with other results found in previous publications. The inclinometer has proved to be a highly reliable tool for measuring the hip abduction range of motion in children with CP, which opens up new possibilities in this field, despite having some measurement limitations.</p
A new hammer to crack an old nut : interspecific competitive resource capture by plants is regulated by nutrient supply, not climate
Peer reviewedPublisher PD
Maternal obesity support services: a qualitative study of the perspectives of women and midwives
Background -
Twenty percent of pregnant women in the UK are obese (BMI â„ 30 kg/m2), reflecting the growing public health challenge of obesity in the 21st century. Obesity increases the risk of adverse outcomes during pregnancy and birth and has significant cost implications for maternity services. Gestational weight management strategies are a high priority; however the evidence for effective, feasible and acceptable weight control interventions is limited and inconclusive. This qualitative study explored the experiences and perceptions of pregnant women and midwives regarding existing support for weight management in pregnancy and their ideas for service development.
Methods -
A purposive sample of 6 women and 7 midwives from Doncaster, UK, participated in two separate focus groups. Transcripts were analysed thematically.
Results -
Two overarching themes were identified, 'Explanations for obesity and weight management' and 'Best care for pregnant women'. 'Explanations' included a lack of knowledge about weight, diet and exercise during pregnancy; self-talk messages which excused overeating; difficulties maintaining motivation for a healthy lifestyle; the importance of social support; stigmatisation; and sensitivity surrounding communication about obesity between midwives and their clients. 'Best care' suggested that weight management required care which was consistent and continuous, supportive and non-judgemental, and which created opportunities for interaction and mutual support between obese pregnant women.
Conclusions -
Women need unambiguous advice regarding healthy lifestyles, diet and exercise in pregnancy to address a lack of knowledge and a tendency towards unhelpful self-talk messages. Midwives expressed difficulties in communicating with their clients about their weight, given awareness that obesity is a sensitive and potentially stigmatising issue. This indicates more could be done to educate and support them in their work with obese pregnant women. Motivation and social support were strong explanatory themes for obesity and weight management, suggesting that interventions should focus on motivational strategies and social support facilitation
Head Position in Stroke Trial (HeadPoST)- sitting-up vs lying-flat positioning of patients with acute stroke: study protocol for a cluster randomised controlled trial
Background
Positioning a patient lying-flat in the acute phase of ischaemic stroke may improve recovery and reduce disability, but such a possibility has not been formally tested in a randomised trial. We therefore initiated the Head Position in Stroke Trial (HeadPoST) to determine the effects of lying-flat (0°) compared with sitting-up (â„30°) head positioning in the first 24 hours of hospital admission for patients with acute stroke.
Methods/Design
We plan to conduct an international, cluster randomised, crossover, open, blinded outcome-assessed clinical trial involving 140 study hospitals (clusters) with established acute stroke care programs. Each hospital will be randomly assigned to sequential policies of lying-flat (0°) or sitting-up (â„30°) head position as a âbusiness as usualâ stroke care policy during the first 24 hours of admittance. Each hospital is required to recruit 60 consecutive patients with acute ischaemic stroke (AIS), and all patients with acute intracerebral haemorrhage (ICH) (an estimated average of 10), in the first randomised head position policy before crossing over to the second head position policy with a similar recruitment target. After collection of in-hospital clinical and management data and 7-day outcomes, central trained blinded assessors will conduct a telephone disability assessment with the modified Rankin Scale at 90 days. The primary outcome for analysis is a shift (defined as improvement) in death or disability on this scale. For a cluster size of 60 patients with AIS per intervention and with various assumptions including an intracluster correlation coefficient of 0.03, a sample size of 16,800 patients at 140 centres will provide 90 % power (α 0.05) to detect at least a 16 % relative improvement (shift) in an ordinal logistic regression analysis of the primary outcome. The treatment effect will also be assessed in all patients with ICH who are recruited during each treatment study period.
Discussion
HeadPoST is a large international clinical trial in which we will rigorously evaluate the effects of different head positioning in patients with acute stroke.
Trial registration
ClinicalTrials.gov identifier: NCT02162017 (date of registration: 27 April 2014); ANZCTR identifier: ACTRN12614000483651 (date of registration: 9 May 2014). Protocol version and date: version 2.2, 19 June 2014
Fit to Race: Identifying the balance, type and sources of knowledge in fitness for Motorsport
In Motorsport, due perhaps to a lack of empirical evidence, it is not always clear what fitness training is required and what roles specific fitness components play, particularly outside the elite levels. Consequently, drivers and their trainers are often left to their own devices, placing reliance on anecdotal information. Accordingly, using a large sample of racing drivers, coaches and fitness trainers, the aim of this investigation was to identify the perceived importance and contribution of fitness components, the sources of information used to reach these conclusions and levels of confidence in the views reported. Survey data from 166 drivers (151 males, 15 females) showed that, in general, cardiovascular fitness, upper body strength, coordination and reactions were perceived as being the most important. Data on sources of information used supported the conjecture that training can often be based on âword of mouthâ. Despite a fairly high level of confidence in the views expressed, there is clearly a significant opportunity for practitioners working within Motorsport to provide clearer, proven information so that drivers can feel confident that they are training optimally
Inter-annual decrease in pulse rate and peak frequency of Southeast Pacific blue whale song types
The decrease in the frequency of two southeast Pacific blue whale song types was examined over decades, usingacoustic data from several different sources ranging between the Equator and Chilean Patagonia. The pulse rate ofthe song units as well as their peak frequency were measured using two different methods (summed auto-correlationand Fourier transform). The sources of error associated with each measurement were assessed. There was a lineardecline in both parameters for the more common song type (southeast Pacific song type n ⊠2). An abbreviated analysisalso showed a frequency decline in the scarcer southeast Pacific song type n ⊠1 between 1970 to 2014, revealing thatboth song types are declining at similar rates. We discussed the use of measuring both pulse rate and peak frequencyto examine the frequency decline. Finally, a comparison of the rates of frequency decline with other song typesreported in the literature is presented.La dĂ©croissance en frĂ©quence des deux chants de baleine bleue de l'ocĂ©an pacifique sud est est examinĂ© sur plusieurs dĂ©cennies en utilisant comme source des donnĂ©es acoustiques de l'Equateur Ă la Patagonie chilienne. La frĂ©quence de pulsation et la frĂ©quence pic des signaux sont mesurĂ©s en utilisant deux mĂ©thodes distinctes (auto-corrĂ©lation sommĂ©e et transformĂ©e de Fourier rapide). Les sources d'erreur associĂ©es Ă chaque mesure sont estimĂ©es. Il y a un dĂ©clin linĂ©aire de ces deux frĂ©quences pour le chant le plus commun de cette zone (chant du Pacifique Sud Est n°2, SEP2). Un analyse plus rapide montre aussi une baisse linĂ©aire, entre 1970 et 2014, de la frĂ©quence du chant SEP1, plus rarement enregistrĂ© dans cette zone. Ces deux baisses ont des amplitudes similaires. L'intĂ©rĂȘt de mesurer la frĂ©quence de pulsation et la frĂ©quence pic de façon concomitante est estimĂ©. Enfin, une comparaison globale des dĂ©clins en frĂ©quence de tous les types de chants de baleines bleues est fournie
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