3,960 research outputs found
The role of mucilage in the attachment of conidia, germ tubes and appressoria in the saprobic aquatic hyphomycetes Lemonniera aquatica and Mycocentrospora filiformis
Spore attachment of the saprobic aquatic Hyphomycetes Lemonniera aquatica and Mycocentrospora filiformis was compared on Thermanox cover slips at the scanning and transmission electron microscope levels. The strength of attachment to Perspex discs was measured with the Fowler cell adhesion measurement module. Data are presented on the initial attachment of conidia and subsequent attachment of germ tubes, hyphae, and appressoria. Attachment at all stages was mediated by mucilage. Both fungi exhibited a similar strength of initial conidial attachment, but attachment resulted from different strategies: (i) in L. aquatica, by active release of mucilage as a result of a thigmotropic response to the substratum; (ii) in M. filiformis, by a passive process involving attachment by pre-existing conidial mucilage prior to contact with the substratum. The strength of attachment increased with settlement time. A fast germination rate, concurrent with mucilage production, resulted in the firm attachment of L. aquatica conidia, while initial germination in M. filiformis was slow and this corresponded to a comparatively weaker conidial attachment. Further increase in the strength of attachment was the result of greater hyphal development, and most importantly, by appressorium formation. All these structures were enrobed in a mucilanginous sheath, although variations were observed in the morphology and texture of mucilages. This suggested differences in chemical composition of mucilage (I) between the two fungi, and (ii) among different structures of the same fungus.published_or_final_versio
Composition and distribution of the peracarid crustacean fauna along a latitudinal transect off Victoria Land (Ross Sea, Antarctica) with special emphasis on the Cumacea
The following study was the first to describe composition and structure of the peracarid fauna systematically along a latitudinal transect off Victoria Land (Ross Sea, Antarctica). During the 19th Antarctic expedition of the Italian research vessel “Italica” in February 2004, macrobenthic samples were collected by means of a Rauschert dredge with a mesh size of 500 m at depths between 85 and 515 m. The composition of peracarid crustaceans, especially Cumacea was investigated. Peracarida contributed 63% to the total abundance of the fauna. The peracarid samples were dominated by amphipods (66%), whereas cumaceans were represented with 7%. Previously, only 13 cumacean species were known, now the number of species recorded from the Ross Sea increased to 34. Thus, the cumacean fauna of the Ross Sea, which was regarded as the poorest in terms of species richness, has to be considered as equivalent to that of other high Antarctic areas. Most important cumacean families concerning abundance and species richness were Leuconidae, Nannastacidae, and Diastylidae. Cumacean diversity was lowest at the northernmost area (Cape Adare). At the area off Coulman Island, which is characterized by muddy sediment, diversity was highest. Diversity and species number were higher at the deeper stations and abundance increased with latitude. A review of the bathymetric distribution of the Cumacea from the Ross Sea reveals that most species distribute across the Antarctic continental shelf and slope. So far, only few deep-sea records justify the assumption of a shallow-water–deep-sea relationship in some species of Ross Sea Cumacea, which is discussed from an evolutionary point of view
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Functional inks and printing of two-dimensional materials.
Graphene and related two-dimensional materials provide an ideal platform for next generation disruptive technologies and applications. Exploiting these solution-processed two-dimensional materials in printing can accelerate this development by allowing additive patterning on both rigid and conformable substrates for flexible device design and large-scale, high-speed, cost-effective manufacturing. In this review, we summarise the current progress on ink formulation of two-dimensional materials and the printable applications enabled by them. We also present our perspectives on their research and technological future prospects
Muscle fiber conduction velocity is more affected after eccentric than concentric exercise
It has been shown that mean muscle fiber conduction velocity (CV) can be acutely impaired after eccentric exercise. However, it is not known whether this applies to other exercise modes. Therefore, the purpose of this experiment was to compare the effects of eccentric and concentric exercises on CV, and amplitude and frequency content of surface electromyography (sEMG) signals up to 24 h post-exercise. Multichannel sEMG signals were recorded from biceps brachii muscle of the exercised arm during isometric maximal voluntary contraction (MVC) and electrically evoked contractions induced by motor-point stimulation before, immediately after and 2 h after maximal eccentric (ECC group, N = 12) and concentric (CON group, N = 12) elbow flexor exercises. Isometric MVC decreased in CON by 21.7 ± 12.0% (± SD, p < 0.01) and by 30.0 ± 17.7% (p < 0.001) in ECC immediately post-exercise when compared to baseline. At 2 h post-exercise, ECC showed a reduction in isometric MVC by 24.7 ± 13.7% (p < 0.01) when compared to baseline, while no significant reduction (by 8.0 ± 17.0%, ns) was observed in CON. Similarly, reduction in CV was observed only in ECC both during the isometric MVC (from baseline of 4.16 ± 0.3 to 3.43 ± 0.4 m/s, p < 0.001) and the electrically evoked contractions (from baseline of 4.33 ± 0.4 to 3.82 ± 0.3 m/s, p < 0.001). In conclusion, eccentric exercise can induce a greater and more prolonged reduction in muscle force production capability and CV than concentric exercis
Integrating modelling and smart sensors for environmental and human health.
Sensors are becoming ubiquitous in everyday life, generating data at an unprecedented rate and scale. However, models that assess impacts of human activities on environmental and human health, have typically been developed in contexts where data scarcity is the norm. Models are essential tools to understand processes, identify relationships, associations and causality, formalize stakeholder mental models, and to quantify the effects of prevention and interventions. They can help to explain data, as well as inform the deployment and location of sensors by identifying hotspots and areas of interest where data collection may achieve the best results. We identify a paradigm shift in how the integration of models and sensors can contribute to harnessing 'Big Data' and, more importantly, make the vital step from 'Big Data' to 'Big Information'. In this paper, we illustrate current developments and identify key research needs using human and environmental health challenges as an example.E.S. is funded by NIH R21ES024715. M.C. gratefully acknowledges the Minnesota Discovery, Research and InnoVation Economy (MnDRIVE) “Global Food Venture” funding and the Institute on the Environment “Discovery Grant” funding at the University of Minnesota Twin-Cities. S.R. and S.S. acknowledge the support for the conceptual development and testing of personal exposure monitoring methods by the UK Natural Environment Research Council through National Capability funding.This is the final version of the article. It was first available from Elsevier via http://dx.doi.org/10.1016/j.envsoft.2015.06.00
Infrared Emission from Supernova Remnants: Formation and Destruction of Dust
We review the observations of dust emission in supernova rem- nants (SNRs)
and supernovae (SNe). Theoretical calculations suggest that SNe, particularly
core-collapse, should make significant quantities of dust, perhaps as much as a
solar mass. Observations of extragalactic SNe have yet to find anywhere near
this amount, but this may be the result of observa- tional limitations. SN
1987A, in the process of transitioning from a SN to an SNR, does show signs of
a significant amount of dust forming in its ejecta, but whether this dust will
survive the passage of the reverse shock to be injected into the ISM is
unknown. IR observations of SNRs have not turned up significant quantities of
dust, and the dust that is observed is generally swept-up by the forward shock,
rather than created in the ejecta. Because the shock waves also destroy dust in
the ISM, we explore the question of whether SNe might be net destroyers, rather
than net creators of dust in the universe.Comment: Published in the Springer Handbook of Supernova
Hotline sessions presented at the American College of Cardiology Congress 2009
The article summarizes the results of clinical trials in the field of cardiovascular medicine, which were presented during the Hotline Sessions at the annual meeting of the American College of Cardiology in Orlando, USA, from 28th March to 31st March 2009. The data were presented by leading experts in the field with relevant positions within the trials. Unpublished reports should be considered as preliminary data as the analysis may change in the final publications. The summaries presented in the manuscript were generated from the oral presentations and provide the readers with the comprehensive information on the results of the latest clinical trials in cardiovascular medicine
How do you say ‘hello’? Personality impressions from brief novel voices
On hearing a novel voice, listeners readily form personality impressions of that speaker. Accurate or not, these impressions are known to affect subsequent interactions; yet the underlying psychological and acoustical bases remain poorly understood. Furthermore, hitherto studies have focussed on extended speech as opposed to analysing the instantaneous impressions we obtain from first experience. In this paper, through a mass online rating experiment, 320 participants rated 64 sub-second vocal utterances of the word ‘hello’ on one of 10 personality traits. We show that: (1) personality judgements of brief utterances from unfamiliar speakers are consistent across listeners; (2) a two-dimensional ‘social voice space’ with axes mapping Valence (Trust, Likeability) and Dominance, each driven by differing combinations of vocal acoustics, adequately summarises ratings in both male and female voices; and (3) a positive combination of Valence and Dominance results in increased perceived male vocal Attractiveness, whereas perceived female vocal Attractiveness is largely controlled by increasing Valence. Results are discussed in relation to the rapid evaluation of personality and, in turn, the intent of others, as being driven by survival mechanisms via approach or avoidance behaviours. These findings provide empirical bases for predicting personality impressions from acoustical analyses of short utterances and for generating desired personality impressions in artificial voices
The effect of limb preference on braking strategy and knee joint mechanics during pivoting in female soccer players
Purpose: The purpose of this study was to explore whether limb preference influences braking strategy and knee joint mechanics during a 180° pivot task in female soccer players.
Methods: Three-dimensional motion analyses of pivoting on the preferred and non-preferred kicking limbs were performed using 10 Qualisys ‘Oqus 7ʹ infrared cameras (240 Hz). Ground reaction forces (GRF) were collected from two AMTI force platforms (1200 Hz) embedded into the running track to examine penultimate (PEN) and final (FC) contact.
Results: Both preferred and non-preferred limbs involved greater hip (ES = 2.85–3.81) and knee joint flexion angles (ES = 5.74–5.78) and peak vertical GRFs (ES = 0.87–1.61), but lower average vertical (ES = 2.55–3.01) and horizontal GRFs (ES = 3.05–3.67) during the PEN compared to the FC. Knee abduction angles were very likely greater (ES = 0.61) when turning off the non-preferred limb compared to the preferred limb.
Conclusion: These findings may help us question the role of limb preference during pivoting, yet knee abduction angles and moments should be monitored with caution in female soccer players. Thus, it remains inconclusive the role limb preference plays in change of direction biomechanics for performance and risk of injury.<br/
Can standardized patients replace physicians as OSCE examiners?
BACKGROUND: To reduce inter-rater variability in evaluations and the demand on physician time, standardized patients (SP) are being used as examiners in OSCEs. There is concern that SP have insufficient training to provide valid evaluation of student competence and/or provide feedback on clinical skills. It is also unknown if SP ratings predict student competence in other areas. The objectives of this study were: to examine student attitudes towards SP examiners; to compare SP and physician evaluations of competence; and to compare predictive validity of these scores, using performance on the multiple choice questions examination (MCQE) as the outcome variable. METHODS: This was a cross-sectional study of third-year medical students undergoing an OSCE during the Internal Medicine clerkship rotation. Fifty-two students rotated through 8 stations (6 physician, 2 SP examiners). Statistical tests used were Pearson's correlation coefficient, two-sample t-test, effect size calculation, and multiple linear regression. RESULTS: Most students reported that SP stations were less stressful, that SP were as good as physicians in giving feedback, and that SP were sufficiently trained to judge clinical skills. SP scored students higher than physicians (mean 90.4% +/- 8.9 vs. 82.2% +/- 3.7, d = 1.5, p < 0.001) and there was a weak correlation between the SP and physician scores (coefficient 0.4, p = 0.003). Physician scores were predictive of summative MCQE scores (regression coefficient = 0.88 [0.15, 1.61], P = 0.019) but there was no relationship between SP scores and summative MCQE scores (regression coefficient = -0.23, P = 0.133). CONCLUSION: These results suggest that SP examiners are acceptable to medical students, SP rate students higher than physicians and, unlike physician scores, SP scores are not related to other measures of competence
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