613 research outputs found
Stronger diversity effects with increased environmental stress : a study of multitrophic interactions between oak, powdery mildew and ladybirds
Recent research has suggested that increasing neighbourhood tree species diversity may mitigate the impact of pests or pathogens by supporting the activities of their natural enemies and/or reducing the density of available hosts. In this study, we attempted to assess these mechanisms in a multitrophic study system of young oak (Quercus), oak powdery mildew (PM, caused by Erysiphe spp.) and a mycophagous ladybird (Psyllobora vigintiduo-punctata). We assessed ladybird mycophagy on oak PM in function of different neighbourhood tree species compositions. We also evaluated whether these species interactions were modulated by environmental conditions as suggested by the Stress Gradient Hypothesis. We adopted a complementary approach of a field experiment where we monitored oak saplings subjected to a reduced rainfall gradient in a young planted forest consisting of different tree species mixtures, as well as a lab experiment where we independently evaluated the effect of different watering treatments on PM infections and ladybird mycophagy. In the field experiment, we found effects of neighbourhood tree species richness on ladybird mycophagy becoming more positive as the target trees received less water. This effect was only found as weather conditions grew drier. In the lab experiment, we found a preference of ladybirds to graze on infected leaves from trees that received less water. We discuss potential mechanisms that might explain this preference, such as emissions of volatile leaf chemicals. Our results are in line with the expectations of the Natural Enemies Hypothesis and support the hypothesis that biodiversity effects become stronger with increased environmental stress
Photocatalytic activity of nitrogen-doped TiO2-based nanowires: a photo-assisted Kelvin probe force microscopy study
The emerging industrial business partnerships, which feature cross-functional and cross-company development efforts, raise the barrier for the establishment of effective knowledge sharing practices in the larger organization. This chapter aims to highlight the role of knowledge as a key enabler for effective engineering activities in the light of such emerging enterprise collaboration models. Knowledge Enabled Engineering (KEE) is presented as an approach to enhance the extended organization’s capability to establish effective collaboration among its parts, in spite of different organizational structures, technologies or processes. KEE is analysed in its constituent parts, highlighting areas, methods and tools that are particularly interesting for leveraging companies’ knowledge sharing capabilities
Towards a collaborative research: A case study on linking science to farmers' perceptions and knowledge on Arabica coffee pests and diseases and its management
The scientific community has recognized the importance of integrating farmer's perceptions and knowledge (FPK) for the development of sustainable pest and disease management strategies. However, the knowledge gap between indigenous and scientific knowledge still contributes to misidentification of plant health constraints and poor adoption of management solutions. This is particularly the case in the context of smallholder farming in developing countries. In this paper, we present a case study on coffee production in Uganda, a sector depending mostly on smallholder farming facing a simultaneous and increasing number of socio-ecological pressures. The objectives of this study were (i) to examine and relate FPK on Arabica Coffee Pests and Diseases (CPaD) to altitude and the vegetation structure of the production systems; (ii) to contrast results with perceptions from experts and (iii) to compare results with field observations, in order to identify constraints for improving the information flow between scientists and farmers. Data were acquired by means of interviews and workshops. One hundred and fifty farmer households managing coffee either at sun exposure, under shade trees or inter-cropped with bananas and spread across an altitudinal gradient were selected. Field sampling of the two most important CPaD was conducted on a subset of 34 plots. The study revealed the following findings: (i) Perceptions on CPaD with respect to their distribution across altitudes and perceived impact are partially concordant among farmers, experts and field observations (ii) There are discrepancies among farmers and experts regarding management practices and the development of CPaD issues of the previous years. (iii) Field observations comparing CPaD in different altitudes and production systems indicate ambiguity of the role of shade trees. According to the locality-specific variability in CPaD pressure as well as in FPK, the importance of developing spatially variable and relevant CPaD control practices is proposed. (Résumé d'auteur
Measurement of the Bottom-Strange Meson Mixing Phase in the Full CDF Data Set
We report a measurement of the bottom-strange meson mixing phase \beta_s
using the time evolution of B0_s -> J/\psi (->\mu+\mu-) \phi (-> K+ K-) decays
in which the quark-flavor content of the bottom-strange meson is identified at
production. This measurement uses the full data set of proton-antiproton
collisions at sqrt(s)= 1.96 TeV collected by the Collider Detector experiment
at the Fermilab Tevatron, corresponding to 9.6 fb-1 of integrated luminosity.
We report confidence regions in the two-dimensional space of \beta_s and the
B0_s decay-width difference \Delta\Gamma_s, and measure \beta_s in [-\pi/2,
-1.51] U [-0.06, 0.30] U [1.26, \pi/2] at the 68% confidence level, in
agreement with the standard model expectation. Assuming the standard model
value of \beta_s, we also determine \Delta\Gamma_s = 0.068 +- 0.026 (stat) +-
0.009 (syst) ps-1 and the mean B0_s lifetime, \tau_s = 1.528 +- 0.019 (stat) +-
0.009 (syst) ps, which are consistent and competitive with determinations by
other experiments.Comment: 8 pages, 2 figures, Phys. Rev. Lett 109, 171802 (2012
Prefrontal cortex activation and young driver behaviour: a fNIRS study
Road traffic accidents consistently show a significant over-representation for young, novice and particularly male drivers. This research examines the prefrontal cortex activation of young drivers and the changes in activation associated with manipulations of mental workload and inhibitory control. It also considers the explanation that a lack of prefrontal cortex maturation is a contributing factor to the higher accident risk in this young driver population. The prefrontal cortex is associated with a number of factors including mental workload and inhibitory control, both of which are also related to road traffic accidents. This experiment used functional near infrared spectroscopy to measure prefrontal cortex activity during five simulated driving tasks: one following task and four overtaking tasks at varying traffic densities which aimed to dissociate workload and inhibitory control. Age, experience and gender were controlled for throughout the experiment. The results showed that younger drivers had reduced prefrontal cortex activity compared to older drivers. When both mental workload and inhibitory control increased prefrontal cortex activity also increased, however when inhibitory control alone increased there were no changes in activity. Along with an increase in activity during overtaking manoeuvres, these results suggest that prefrontal cortex activation is more indicative of workload in the current task. There were no differences in the number of overtakes completed by younger and older drivers but males overtook significantly more than females. We conclude that prefrontal cortex activity is associated with the mental workload required for overtaking. We additionally suggest that the reduced activation in younger drivers may be related to a lack of prefrontal maturation which could contribute to the increased crash risk seen in this population
2017 HRS/EHRA/ECAS/APHRS/SOLAECE expert consensus statement on catheter and surgical ablation of atrial fibrillation: executive summary.
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Tuning fresh: radiation through rewiring of central metabolism in streamlined bacteria
Most free-living planktonic cells are streamlined and in spite of their limitations in functional flexibility, their vast populations have radiated into a wide range of aquatic habitats. Here we compared the metabolic potential of subgroups in the Alphaproteobacteria lineage SAR11 adapted to marine and freshwater habitats. Our results suggest that the successful leap from marine to freshwaters in SAR11 was accompanied by a loss of several carbon degradation pathways and a rewiring of the central metabolism. Examples for these are C1 and methylated compounds degradation pathways, the Entner–Doudouroff pathway, the glyoxylate shunt and anapleuretic carbon fixation being absent from the freshwater genomes. Evolutionary reconstructions further suggest that the metabolic modules making up these important freshwater metabolic traits were already present in the gene pool of ancestral marine SAR11 populations. The loss of the glyoxylate shunt had already occurred in the common ancestor of the freshwater subgroup and its closest marine relatives, suggesting that the adaptation to freshwater was a gradual process. Furthermore, our results indicate rapid evolution of TRAP transporters in the freshwater clade involved in the uptake of low molecular weight carboxylic acids. We propose that such gradual tuning of metabolic pathways and transporters toward locally available organic substrates is linked to the formation of subgroups within the SAR11 clade and that this process was critical for the freshwater clade to find and fix an adaptive phenotype.This work was supported by the Swedish Research Council (Grant Numbers 2012-4592 to AE and 2012-3892 to SB) and the Communiy Sequencing Programme of the US Department of Energy Joint Genome Institute. The work conducted by the US Department of Energy Joint Genome Institute, a DOE Office of Science User Facility, is supported under Contract No. DE-AC02-05CH11231
The Opportunistic Pathogen Propionibacterium acnes: Insights into Typing, Human Disease, Clonal Diversification and CAMP Factor Evolution
We previously described a Multilocus Sequence Typing (MLST) scheme based on eight genes that facilitates population
genetic and evolutionary analysis of P. acnes. While MLST is a portable method for unambiguous typing of bacteria, it is
expensive and labour intensive. Against this background, we now describe a refined version of this scheme based on two
housekeeping (aroE; guaA) and two putative virulence (tly; camp2) genes (MLST4) that correctly predicted the phylogroup
(IA1, IA2, IB, IC, II, III), clonal complex (CC) and sequence type (ST) (novel or described) status for 91% isolates (n = 372) via
cross-referencing of the four gene allelic profiles to the full eight gene versions available in the MLST database (http://
pubmlst.org/pacnes/). Even in the small number of cases where specific STs were not completely resolved, the MLST4
method still correctly determined phylogroup and CC membership. Examination of nucleotide changes within all the MLST
loci provides evidence that point mutations generate new alleles approximately 1.5 times as frequently as recombination;
although the latter still plays an important role in the bacterium’s evolution. The secreted/cell-associated ‘virulence’ factors
tly and camp2 show no clear evidence of episodic or pervasive positive selection and have diversified at a rate similar to
housekeeping loci. The co-evolution of these genes with the core genome might also indicate a role in commensal/normal
existence constraining their diversity and preventing their loss from the P. acnes population. The possibility that members of
the expanded CAMP factor protein family, including camp2, may have been lost from other propionibacteria, but not P.
acnes, would further argue for a possible role in niche/host adaption leading to their retention within the genome. These
evolutionary insights may prove important for discussions surrounding camp2 as an immunotherapy target for acne, and
the effect such treatments may have on commensal lineages
The Efficacy of Education with the WHO Dengue Algorithm on Correct Diagnosing and Triaging of Dengue-Suspected Patients; Study in Public Health Centre
Background: Correct diagnosing and triaging dengue fever remains clinical, but is difficult because of unspecific flu-like symptoms. Best tool at the moment is the easy–to-use 2009 WHO guidelines. Objective: To investigate the efficacy of educational intervention with the (adapted and translated) algorithm from the 2009 WHO dengue guideline to healthcare providers in the Indonesian primary health care setting of Central Java. Methods: Quasi-randomized intervention study implemented in two Public Health Centres (PHCs), one being intervention and the other control. Intervention consisted of educational actions on healthcare providers with a presentation, hand-outs and posters. All patients with fever seen in policlinic or emergency department were included. Data were collected with a participatory observation using the WHO algorithm as a guidance. Results: Pre-intervention, a total of 88 patients (n=38 intervention group; n=50 in the control group), and post-intervention, a total of 231 patients (n=105 in the intervention group; n=126 in the control group) were included. Pre-intervention, correct diagnosing and triaging was not significantly different (63.2% vs 64.0% ; p=0.935), while post-intervention, the intervention group scored higher (75.2% vs 62.7% ; p=0.041). However, in both pre- and post-interventional phase, more than 50% of the cases in 19/22 domains were not investigated by the intervention group. Conclusion: Statistical analyses showed a significantly better outcome in correct diagnosis in the intervention group. However, results are considered inconclusive due to incompleteness of relevant information, which most probably leads to many false positive correct diagnoses and triaging
Relationship between the Daily Rhythm of Distal Skin Temperature and Brown Adipose Tissue 18F-FDG Uptake in Young Sedentary Adults
The present study examines whether the daily rhythm of distal skin
temperature (DST) is associated with brown adipose tissue (BAT) metabolism
as determined by 18F-fluorodeoxyglucose (18F-FDG) uptake in young adults.
Using a wireless thermometer (iButton) worn on the nondominant wrist, DST
was measured in 77 subjects (26% male; age 22 ± 2 years; body mass index 25.2
± 4.8 kg/m2) for 7 consecutive days. The temperatures to which they were
habitually exposed over the day were also recorded. The interday stability of
DST was calculated from the collected data, along with the intraday variability
and relative amplitude; the mean temperature of the 5 and 10 consecutive
hours with the maximum and minimum DST values, respectively; and when
these hours occurred. Following exposure to cold, BAT volume and mean and
peak standardized 18F-FDG uptake (SUVmean and SUVpeak) were determined for
each subject via static 18F-FDG positron emission tomography/computed
tomography scanning. Relative amplitude and the time at which the 10 consecutive
hours of minimum DST values occurred were positively associated
with BAT volume, SUVmean, and SUVpeak (p ≤ 0.02), whereas the mean DST of
that period was inversely associated with the latter BAT variables (p ≤ 0.01).
The interday stability and intraday variability of the DST were also associated
(directly and inversely, respectively) with BAT SUVpeak (p ≤ 0.02 for both). All
of these associations disappeared, however, when the analyses were adjusted
for the ambient temperature to which the subjects were habitually exposed. Thus, the relationship between the daily rhythm of DST and BAT activity estimated
by 18F-FDG uptake is masked by environmental and likely behavioral
factors. Of note is that those participants exposed to the lowest ambient temperature
showed 3 to 5 times more BAT volume and activity compared with
subjects who were exposed to a warmer ambient temperature
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