1,109 research outputs found
Digestive enzymes of vine weevil (Otiorhynchus sulcatus) as potential targets for insect control strategies.
Over the previous quarter century the vine weevil (Otiorhynchus sulcatus) has become a pest of horticultural and agricultural plants. The vine weevil is a polyphagous coleopteran insect and is able to attack over one hundred different plant species. Its spread has been limited by its lack of flight but modern world trade in live container grown plants has spread the insect to new habitats. Damage to plants caused by vine weevil is two fold, with the larvae destroying root balls while the adults attack the, leaves. The larval stage, in particular is difficult to treat with conventional insecticides unless environmentally undesirable soil treatments are used. The current lack of defence against the vine weevil has opened the door for methods of crop protection through the generation of genetically modified plants. The design of an efficient GM approach to control the vine weevil requires a sound knowledge of the insect’s digestive enzymes, which may be used as potential targets for insecticidal proteins. This approach was achieved for the vine weevil through analysis of active digestive proteases in the insects gut and the identification of suitable proteinase inhibitors which would reduce the overall level of protein hydrolysis. Using this method it was discovered that the vine weevil contained both serine and cysteine proteases in addition to a range of other digestive hydrolases. This biochemical data was supported by a molecular approach to isolate cDNA clones associated with the insect's digestive tract. Using a gut specific cDNA library clones encoding a cathepsin B protease, two trypsin proteases, a pectinesterase, a lipase and a cellulase were isolated and characterised. The cellulase isolated from vine weevil has been shown to originate from the insect genome as shown through Southern Blot analysis and sequencing across several intronic regions. Evidence presented herein shows that the vine weevil gut extract hydrolyses both cellulose and cellobiose. Similar results were observed with recombinant protein expressed in the eukaryotic yeast P.pastoris. Furthermore data presented here shows that the vine weevil has the full complement of enzymes needed for the complete digestion of crystalline cellulose, which was until recently believed to be the sole domain of several species of bacteria and yeast. In addition a cDNA clone encoded a vine weevil endogenous chitinase was isolated from the cDNA library. This chitinase cDNA and one encoding the proteinase inhibitor Oryzacystatin-I were used to generate transgenic tobacco plants which have been shown to express the transgene. These transgenic plants are the first step in developing a strategy for plant protection against vine weevil based on genetic modification
A Preliminary Investigation of Child, Parent and Programme Leader Reflections on Participation in and Delivery of a Family- Based Weight Intervention Programme.
Childhood obesity is considered to be the greatest public health risk to children today, placing young people at considerable risk for adult obesity and consequent CVD, diabetes, liver dysfunction, and other morbidities (Doro-Altan et al., 2008; Singh et al., 2008). As a result numerous interventions with the potential to reduce obesity levels or associated risk of chronic diseases have been devised (Steinberger et al., 2003; Flynn et al., 2006). Not withstanding the need for further quantitative evaluation of the effect of such interventions, key publications have now called for qualitative evaluations to be undertaken in order to create an evidence base from the views of participants that may highlight why certain interventions may be more, or less successful (National Institute for Health and Clinical Excellence, 2006; Luttikhuis et al., 2009).
In response to these very recent calls, this abstract intends to present, from qualitative methods of enquiry, preliminary findings of parent, child and programme leader experiences of, reflections on and future intentions following participation in and delivery of a nationally implemented family-based weight intervention programme in the UK. Data from semi-structured interviews with 6 families who completed the programme in December 2008 and 1 programme leader will be presented. Informal thematic analysis will be utilised to identify emergent themes with data presentation accentuating the qualitative, ‘lived’ experience of the programme and the impact of the various aspects of the intervention on intentions for future behaviours. It is anticipated that the outcomes of this study will help to inform the organisation, content, implementation and nature of future intervention programmes in order to enhance their effectiveness
Age and Grip Strength Predict Hand Dexterity in Adults.
In the scientific literature, there is much evidence of a relationship between age and dexterity,
where increased age is related to slower, less nimble and less smooth, less coordinated
and less controlled performances. While some suggest that the relationship is a direct consequence
of reduced muscle strength associated to increased age, there is a lack of research
that has systematically investigated the relationships between age, strength and
hand dexterity. Therefore, the aim of this study was to examine the associations between
age, grip strength and dexterity. 107 adults (range 18-93 years) completed a series of hand
dexterity tasks (i.e. steadiness, line tracking, aiming, and tapping) and a test of maximal grip
strength. We performed three phases of analyses. Firstly, we evaluated the simple relationships
between pairs of variables; replicating the existing literature; and found significant relationships
of increased age and reduced strength; increased age and reduced dexterity,
and; reduced strength and reduced dexterity. Secondly, we used standard Multiple Regression
(MR) models to determine which of the age and strength factors accounted for the
greater variance in dexterity. The results showed that both age and strength made significant
contributions to the data variance, but that age explained more of the variance in
steadiness and line tracking dexterity, whereas strength explained more of the variance in
aiming and tapping dexterity. In a third phase of analysis, we used MR analyses to show an
interaction between age and strength on steadiness hand dexterity. Simple Slopes posthoc
analyses showed that the interaction was explained by the middle to older aged adults
showing a relationship between reduced strength and reduced hand steadiness, whereas
younger aged adults showed no relationship between strength and steadiness hand dexterity.
The results are discussed in terms of how age and grip strength predict different types of
hand dexterity in adults
A Fundamental Equivalence between Randomized Experiments and Observational Studies
A fundamental probabilistic equivalence between randomized experiments and observational studies is presented. Given a detailed scenario, the reader is asked to consider which of two possible study designs provides more information regarding the expected difference in an outcome due to a time-fixed treatment. A general solution is described, and a particular worked example is also provided. A mathematical proof is given in the appendix. The demonstrated equivalence helps to clarify common ground between randomized experiments and observational studies, and to provide a foundation for considering both the design and interpretation of studies
Enhancing photocatalytic degradation of the cyanotoxin microcystin-LR with the addition of sulfate-radical generating oxidants.
This study investigated the coupling of sulfate radical generating oxidants, (persulfate, PS and peroxymonosulfate, PMS) with TiO2 photocatalysis for the degradation of microcystin-LR (MC-LR). Treatment efficiency was evaluated by estimating the electrical energy per order (EEO). Oxidant addition at 10 mg/L reduced the energy requirements of the treatment by 60% and 12% for PMS and PS, respectively compared with conventional photocatalysis. Quenching studies indicated that both sulfate and hydroxyl radicals contributed towards the degradation of MC-LR for both oxidants, while Electron Paramagnetic Resonance (EPR) studies confirmed that the oxidants prolonged that lifetime of both radicals (concentration maxima shifted from 10 to 20min), allowing for bulk diffusion and enhancing cyanotoxin removal. Structural identification of transformation products (TPs) formed during all treatments, indicated that early stage degradation of MC-LR occurred mainly on the aromatic ring and conjugated carbon double bonds of the ADDA amino acid. In addition, simultaneous hydroxyl substitution of the aromatic ring and the conjugated double carbon bonds of ADDA (m/z= 1027.5) are reported for the first time. Oxidant addition also increased the rates of formation/degradation of TPs and affected the overall toxicity of the treated samples. The detoxification and degradation order of the treatments was UVA/TiO2/PMS > UVA/TiO2/PS>> UVA/TiO2
Proteome phenotypes discriminate the growing location and malting traits in Field-Grown Barley
Barley is one of the key cereal grains for malting and brewing industries. However, climate variability and unprecedented weather events can impact barley yield and end-product quality. The genetic background and environmental conditions are key factors in defining the barley proteome content and malting characteristics. Here, we measure the barley proteome and malting characteristics of three barley lines grown in Western Australia, differing in genetic background and growing location, by applying liquid chromatography–mass spectrometry (LC–MS). Using data-dependent acquisition LC–MS, 1571 proteins were detected with high confidence. Quantitative data acquired using sequential window acquisition of all theoretical (SWATH) MS on barley samples resulted in quantitation of 920 proteins. Multivariate analyses revealed that the barley lines’ genetics and their growing locations are strongly correlated between proteins and desired traits such as the malt yield. Linking meteorological data with proteomic measurements revealed how high-temperature stress in northern regions affects seed temperature tolerance during malting, resulting in a higher malt yield. Our results show the impact of environmental conditions on the barley proteome and malt characteristics; these findings have the potential to expedite breeding programs and malt quality prediction
Comparing Parametric, Nonparametric, and Semiparametric Estimators: The Weibull Trials
We use simple examples to show how the bias and standard error of an estimator depend in part on the type of estimator chosen from among parametric, nonparametric, and semiparametric candidates. We estimated the cumulative distribution function in the presence of missing data with and without an auxiliary variable. Simulation results mirrored theoretical expectations about the bias and precision of candidate estimators. Specifically, parametric maximum likelihood estimators performed best but must be "omnisciently"correctly specified. An augmented inverse probability-weighted (IPW) semiparametric estimator performed best among candidate estimators that were not omnisciently correct. In one setting, the augmented IPW estimator reduced the standard error by nearly 30%, compared with a standard Horvitz-Thompson IPW estimator; such a standard error reduction is equivalent to doubling the sample size. These results highlight the gains and losses that can be incurred when model assumptions are made in any analysis
Combining Sentinel-1 and Landsat 8 does not improve classification accuracy of tropical selective logging
Tropical forests play a key role in the global carbon and hydrological cycles, maintaining biological diversity, slowing climate change, and supporting the global economy and local livelihoods. Yet, rapidly growing populations are driving continued degradation of tropical forests to supply wood products. The United Nations (UN) has developed the Reducing Emissions from Deforestation and Forest Degradation (REDD+) programme to mitigate climate impacts and biodiversity losses through improved forest management. Consistent and reliable systems are still needed to monitor tropical forests at large scales, however, degradation has largely been left out of most REDD+ reporting given the lack of effective monitoring and countries mainly focus on deforestation. Recent advances in combining optical data and Synthetic Aperture Radar (SAR) data have shown promise for improved ability to monitor forest losses, but it remains unclear if similar improvements could be made in detecting and mapping forest degradation. We used detailed selective logging records from three lowland tropical forest regions in the Brazilian Amazon to test the effectiveness of combining Landsat 8 and Sentinel-1 for selective logging detection. We built Random Forest models to classify pixel-based differences in logged and unlogged regions to understand if combining optical and SAR improved the detection capabilities over optical data alone. We found that the classification accuracy of models utilizing optical data from Landsat 8 alone were slightly higher than models that combined Sentinel-1 and Landsat 8. In general, detection of selective logging was high with both optical only and optical-SAR combined models, but our results show that the optical data was dominating the predictive performance and adding SAR data introduced noise, lowering the detection of selective logging. While we have shown limited capabilities with C-band SAR, the anticipated opening of the ALOS-PALSAR archives and the anticipated launch of NISAR and BIOMASS in 2023 should stimulate research investigating similar methods to understand if longer wavelength SAR might improve classification of areas affected by selective logging when combined with optical data
Mass–abundance scaling in avian communities is maintained after tropical selective logging
Selective logging dominates forested landscapes across the tropics. Despite the structural damage incurred, selectively logged forests typically retain more biodiversity than other forest disturbances. Most logging impact studies consider conventional metrics, like species richness, but these can conceal subtle biodiversity impacts. The mass–abundance relationship is an integral feature of ecological communities, describing the negative relationship between body mass and population abundance, where, in a system without anthropogenic influence, larger species are less abundant due to higher energy requirements. Changes in this relationship can indicate community structure and function changes.
We investigated the impacts of selective logging on the mass–abundance scaling of avian communities by conducting a meta‐analysis to examine its pantropical trend. We divide our analysis between studies using mist netting, sampling the understory avian community, and point counts, sampling the entire community.
Across 19 mist‐netting studies, we found no consistent effects of selective logging on mass–abundance scaling relative to primary forests, except for the omnivore guild where there were fewer larger‐bodied species after logging. In eleven point‐count studies, we found a more negative relationship in the whole community after logging, likely driven by the frugivore guild, showing a similar pattern.
Limited effects of logging on mass–abundance scaling may suggest high species turnover in logged communities, with like‐for‐like replacement of lost species with similar‐sized species. The increased negative mass–abundance relationship found in some logged communities could result from resource depletion, density compensation, or increased hunting; potentially indicating downstream impacts on ecosystem functions.
Synthesis and applications. Our results suggest that size distributions of avian communities in logged forests are relatively robust to disturbance, potentially maintaining ecosystem processes in these forests, thus underscoring the high conservation value of logged tropical forests, indicating an urgent need to focus on their protection from further degradation and deforestation
A macroscopic multifractal analysis of parabolic stochastic PDEs
It is generally argued that the solution to a stochastic PDE with
multiplicative noise---such as , where denotes
space-time white noise---routinely produces exceptionally-large peaks that are
"macroscopically multifractal." See, for example, Gibbon and Doering (2005),
Gibbon and Titi (2005), and Zimmermann et al (2000). A few years ago, we proved
that the spatial peaks of the solution to the mentioned stochastic PDE indeed
form a random multifractal in the macroscopic sense of Barlow and Taylor (1989;
1992). The main result of the present paper is a proof of a rigorous
formulation of the assertion that the spatio-temporal peaks of the solution
form infinitely-many different multifractals on infinitely-many different
scales, which we sometimes refer to as "stretch factors." A simpler, though
still complex, such structure is shown to also exist for the
constant-coefficient version of the said stochastic PDE.Comment: 41 page
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