2,518 research outputs found
The chemical identity of intervessel pit membranes in Acer challenges hydrogel control of xylem hydraulic conductivity.
Ion-mediated enhancement of the hydraulic conductivity of xylem tissue (i.e., the ionic effect) has been reported for various angiosperm species. One explanation of the ionic effect is that it is caused by the swelling and shrinking of intervessel pit membranes due to the presence of pectins and/or other cell wall matrix polymers such as heteroxylans or arabinogalactan-proteins (AGPs) that may contain acidic sugars. Here, we examined the ionic effect for six Acer species and their pit membrane chemistry using immunocytochemistry, including antibodies against glycoproteins. Moreover, anatomical features related to the bordered pit morphology and vessel dimensions were investigated using light and electron microscopy. The ionic effect varied from 18% (± 9) to 32% (± 13). Epitopes of homogalacturonan (LM18) and xylan (LM11) were not detected in intervessel pit membranes. Negative results were also obtained for glycoproteins (extensin: LM1, JIM20; AGP glycan: LM2), although AGP (JIM13) related epitopes were detected in parenchyma cells. The mean vessel length was significantly correlated with the magnitude of the ionic effect, unlike other pit or vessel related characteristics.Our results suggest that intervessel pit membranes of Acer are unlikely to contain pectic or other acidic polysaccharides. Therefore, alternative explanations should be tested to clarify the ionic effect
The Dhow's last redoubt? Vestiges of wooden boatbuilding traditions in Yemen
This is an accepted version of an article that went on to be
published in the Proceedings of the Seminar for Arabian Studies
in 2010. The reference for the published version is:
Agius, D.A., Cooper, J.P., Jansen van Rensburg, J.and Zazzaro,
C., 2010 " The dhow's last redoubt? Vestiges of wooden
boatbuilding traditions in Yemen". Proceedings of the Seminar for
Arabian Studies 40: 71â84.
Please use the published version in any citations.The final version of the article is available from Archaeopress via the link in this record.Researchers from the MARES Project visited Yemen in February 2009 in
order to investigate the building and use of traditional wooden boats (âdhowsâ,
in English parlance) in the country. The survey covered the coastline from
Aden to Salif in the Red Sea, and visited centres of traditional dhow building
and use, including Ghureira, Mocha and Khokha. The project aimed to assess
the state of the industry, establish a vessel typology, understand construction
processes, learn about the use of these vessels, and compile a lexicon of
boatbuilding and nautical terms. This article offers the preliminary findings of
the survey, pending more comprehensive publication in the future. The survey
found that, in all locations visited, the building of new vessels had rapidly
diminished in the preceding decade, and had now all but ceased. The only
ongoing activity witnessed during the survey was repairs to existing wooden
craft. In formerly large boat-building centres, wooden boat-builders, mostly
elderly, have ceased work, while younger men were building fishing craft
using fibreglass â the material used in the great majority of vessels in Yemen
today. A preliminary typology of surviving vessel was established. The doubleended
cargo-carrying za<Ä«mahs and zÄrĆ«qs were recorded only as
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abandoned hulks. Double-ended <obrÄ«s and transom-sterned âlarge hĆ«rÄ«sâ,
with their stern-quarter âfinsâ, continued to be used in small numbers for sein
fishing and transporting livestock. Again, most examples were abandoned.
Various forms of small log and plank hĆ«rÄ« âcanoesâ were observed, few still in
use, while the log-raft ramas survives on the Red Sea coast. The terms used
for these vessel types form part of a linguistic survey of dhow activity in
Yemen.This research was conducted as part of the MARES Project, a three-year
programme investigating the maritime past and heritage of the Red Sea and
Arabian-Persian Gulf. MARES is based at the Institute of Arab and Islamic
Studies at the University of Exeter (http://projects.exeter.ac.uk/mares). The
programme is funded by the Golden Web Foundation, an educational charity
registered in the UK (www.goldenweb.org), to which our gratitude is due.
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Thanks are also due to the Seven Pillars of Wisdom Trust, which provided
additional financial support for the fieldwork. In addition, the MARES team
would like to thank the following people for their assistance: Dr Abdulla M.
Bawazir, President of Yemenâs General Organisation of Antiquities and
Museums (GOAM); Dr Muhammad Taha al-Asbahi, General Director of
Antiquities at GOAM; Dr Raja Batawil, head of GOAM in Aden; our GOAMappointed
field companion, Salah al-Mansuri; Mr. Hasan Saleh Shihab; Emily
Allardyce, Fuad Mazid al-Matairi and their colleagues at the British Yemeni
Language Institute; our driver and guide Muhammad al-Matairi; Edward
Prados, Director of Amideast; Chris Evens; the British Council; and the British
Embassy. Last but not least, the team wishes to thank the many individual
informants along Yemenâs coast who gave their assistance to its research
EuroSL â a European taxonomic backbone for vegetation databases and other taxon- related databases: version 1.0
Background: A taxonomic reference list is an indispensable tool to sample, manage and match biodiversity data from different sources. Merging vegetation databases or combining them with taxon-related attributes needs reliable and consistent information about the taxon concepts used and an appropriate naming.
Aim: Creating a âtaxonomic backboneâ of European vascular plants and bryophytes with links to widespread taxonomic references.
Methods: We used the Euro+Med plant list (Euro+Med 2006ff), version 2015/04. For all families not yet covered there we used taxa from Flora Europaea (Tutin et al. 1980ff). Additionally we included the aggregates from the Ehrendorfer (1973) list. For bryophytes we rely on Grolle & Long (2000) and Hill et al. (2006).
Results: EuroSL 1.0 covers > 45T accepted taxa and >77T synonyms from approx. 370 families. At the species level this means approx. 32T accepted names and >44T synonyms.
EuroSL list will be published open access to allow referencing and connecting taxon-related databases beyond country borders. Future releases of EuroSL might contain additional taxonomic groups (algae and lichens), aggregates or new names as needed. However, a thorough documentation and transparency regarding taxon concepts, i.e. name usage = taxon circumscription, given by citing the source lists, will remain the highest priority. The first application of EuroSL will be the compilation of Ecological Indicator Values for Europe (EIVE version 1.0)
Comparative efficacy of long-acting bronchodilators for COPD - a network meta-analysis
Background: Clinicians are faced with an increasingly difficult choice regarding the optimal bronchodilator for
patients with chronic obstructive pulmonary disease (COPD) given the number of new treatments. The objective of this study is to evaluate the comparative efficacy of indacaterol 75/150/300 ÎŒg once daily (OD), glycopyrronium
bromide 50 ÎŒg OD, tiotropium bromide 18 ÎŒg/5 ÎŒg OD, salmeterol 50 ÎŒg twice daily (BID), formoterol 12 ÎŒg BID,
and placebo for moderate to severe COPD.
Methods: Forty randomized controlled trials were combined in a Bayesian network meta-analysis. Outcomes of interest were trough and post-dose forced expiratory volume in 1 second (FEV1), St. Georgeâs Respiratory Questionnaire (SGRQ) score and responders (â„4 points), and Transition Dyspnea Index (TDI) score and responders
(â„1 point) at 6 months.
Results: Indacaterol was associated with a higher trough FEV1 than other active treatments (difference for indacaterol 150 ÎŒg and 300 ÎŒg versus placebo: 152 mL (95% credible interval (CrI): 126, 179); 160 mL (95% CrI:
133, 187)) and the greatest improvement in SGRQ score (difference for indacaterol 150 ÎŒg and 300 ÎŒg versus
placebo: -3.9 (95% CrI -5.2, -2.6); -3.6 (95% CrI -4.8, -2.3)). Glycopyrronium and tiotropium 18 ÎŒg resulted in the
next best estimates for both outcomes with minor differences (difference for glycopyrronium versus tiotropium
for trough FEV1 and SGRQ: 18 mL (95% CrI: -16, 51); -0.55 (95% CrI: -2.04, 0.92).
Conclusion: In terms of trough FEV1 and SGRQ score indacaterol, glycopyrronium, and tiotropium are expected to
be the most effective bronchodilators
What guidance are researchers given on how to present network meta-analyses to end-users such as policymakers and clinicians? A systematic review
© 2014 Sullivan et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Introduction: Network meta-analyses (NMAs) are complex methodological approaches that may be challenging for non-technical end-users, such as policymakers and clinicians, to understand. Consideration should be given to identifying optimal approaches to presenting NMAs that help clarify analyses. It is unclear what guidance researchers currently have on how to present and tailor NMAs to different end-users. Methods: A systematic review of NMA guidelines was conducted to identify guidance on how to present NMAs. Electronic databases and supplementary sources were searched for NMA guidelines. Presentation format details related to sample formats, target audiences, data sources, analysis methods and results were extracted and frequencies tabulated. Guideline quality was assessed following criteria developed for clinical practice guidelines. Results: Seven guidelines were included. Current guidelines focus on how to conduct NMAs but provide limited guidance to researchers on how to best present analyses to different end-users. None of the guidelines provided reporting templates. Few guidelines provided advice on tailoring presentations to different end-users, such as policymakers. Available guidance on presentation formats focused on evidence networks, characteristics of individual trials, comparisons between direct and indirect estimates and assumptions of heterogeneity and/or inconsistency. Some guidelines also provided examples of figures and tables that could be used to present information. Conclusions: Limited guidance exists for researchers on how best to present NMAs in an accessible format, especially for non-technical end-users such as policymakers and clinicians. NMA guidelines may require further integration with end-users' needs, when NMAs are used to support healthcare policy and practice decisions. Developing presentation formats that enhance understanding and accessibility of NMAs could also enhance the transparency and legitimacy of decisions informed by NMAs.The Canadian Institute of Health Research (CIHR) Drug Safety and Effectiveness Network (Funding reference number â 116573)
Bounded Model Checking for Probabilistic Programs
In this paper we investigate the applicability of standard model checking
approaches to verifying properties in probabilistic programming. As the
operational model for a standard probabilistic program is a potentially
infinite parametric Markov decision process, no direct adaption of existing
techniques is possible. Therefore, we propose an on-the-fly approach where the
operational model is successively created and verified via a step-wise
execution of the program. This approach enables to take key features of many
probabilistic programs into account: nondeterminism and conditioning. We
discuss the restrictions and demonstrate the scalability on several benchmarks
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