672 research outputs found
Vegetation indices as indicators of damage by the sunn pest (Hemiptera: Scutelleridae) to field grown wheat
The sunn pest, Eurygaster integriceps Put. (Hemiptera: Scutelleridae), also known as sting or cereal pest, is one of the most economically important pests of wheat in the world. In this study, a collapsiblenylon cloth cage experiments were conducted to determine the feasibility of using remote sensing techniques to detect stress in wheat caused by the density of sunn pests. The results show we candetect the amount of stress in wheat caused by different life stages of sunn pest with a hand-held radiometer. Normalized difference vegetation index (NDVI) based indices; NDVIsg, NDVId, NDVIr, andstructure insensitive pigment index (SIPI) were chosen out of 19 indices initially tested. The NDVI based vegetation indices derived from hyperspectral data, recorded by a hand held spectroradiometer, were used to determine the predicted indices using the initial number of Sunn Pest (NOSP). Overall, r2 values of all predicted indices calculated for 3rd instars were lower than those of 4th and adult stage. When r2was considered separately, predicted NDVIr index value (87.4) was the highest and predicted SIPI index value is lowest (80.7) in 3rd instars. The highest r2 value was obtained in adult stage of sunn pest isNDVIsg (96.9) compare with NDVId (95.5), NDVIr (92.4) and SIPI (94.2). It was also concluded that remote sensing could detect not only the different stages pest damage on wheat, but also the number of sunnpest stages density affect in controlled experiments
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Microdevices for Continuous Sized Based Sorting by AC Dielectrophoresis
This paper was presented at the 4th Micro and Nano Flows Conference (MNF2014), which was held at University College, London, UK. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute, ASME Press, LCN London Centre for Nanotechnology, UCL University College London, UCL Engineering, the International NanoScience Community, www.nanopaprika.eu.In this project, various microfluidic devices are designed for microparticles and cells separation. The dominant regions of dielectrophoresis among other AC Electrokinetic transport mechanisms are predicted. Flow behaviors of particles for each design parameter are modeled and simulated using COMSOL Multiphysics 4.3a software. Lab-on-a-chip devices having a Ti interdigitated electrode layer on a glass substrate and a PDMS microchannel are fabricated to investigate the most effective design solution for separating particles based on their sizes. Polystyrene particles with different diameters of 3.2 ΞΌm and 9.8 ΞΌm are used in our experiments and experiments with circulating tumor cells (CTCs) are in progress
Assessment of the effect of salinity on the early growth stage of the common sunflower (Sanay cultivar) using spectral discrimination techniques
Salinity is one of the main limiting factors for agricultural production. This is especially true in arid and semi-arid regions of the world like Turkey. The objective of this study was to determine if the effect ofsalt concentration on the physiological and physiological features of the sunflower (Helianthus annuus L) could be measured using remote sensing techniques. Sunflower seedlings were grown undercontrolled conditions and irrigated with Β½ Hoagland Solution containing three different concentrations of NaCl (salt) (0.0, 0.5, 1.0 and 1.5%). The results showed that plant growth decreased proportionallywith increasing levels of NaCl. Chlorophyll concentration and a Normalized Difference Vegetation Index (NDVI) were derived for the plants using a spectroradiometer. There was found to be a significant (r2 = 0.76) correlation between chlorophyll and NDVI values. Therefore, factors that can be derived through remote sensing such as NDVI and chlorophyll can be used to indirectly demonstrate the impact salinity has on sunflower plants. Therefore, agriculturalists can assess growth rate changes caused by salinity using remote sensing techniques
Size induced metal insulator transition in nanostructured Niobium thin films: Intragranular and intergranular contributions
With a reduction in the average grain size in nanostructured films of
elemental Nb, we observe a systematic crossover from metallic to
weakly-insulating behavior. An analysis of the temperature dependence of the
resistivity in the insulating phase clearly indicates the existence of two
distinct activation energies corresponding to inter-granular and intra-granular
mechanisms of transport. While the high temperature behavior is dominated by
grain boundary scattering of the conduction electrons, the effect of
discretization of energy levels due to quantum confinement shows up at low
temperatures. We show that the energy barrier at the grain boundary is
proportional to the width of the largely disordered inter-granular region,
which increases with a decrease in the grain size. For a metal-insulator
transition to occur in nano-Nb due to the opening up of an energy gap at the
grain boundary, the critical grain size is ~ 8nm and the corresponding grain
boundary width is ~ 1.1nm
Inspection of Computed Tomography (CT) Data and Finite Element (FE) Simulation of Additive Manufactured (AM) Components
This is the author accepted manuscript. The final version is available from the publisherOne of the challenges of working with Additive Manufactured (AM) metal parts involves checking accuracy and
reliability before production. Techniques used Computed Tomography (CT) scans, 3D image processing, and
Finite Element (FE) simulation help detect problems prior to costly faults. A workflow has been developed by
Synopsys, ANSYS, North Star Imaging, and the University of Pittsburgh to streamline this often-complex
process, with applications to analyzing metal AM-produced lightweight brackets and a component from Moog,
Inc. Software like Synopsys Simplewareβ’ is used to generate robust models from 3D scans of AM parts to
compare original CAD models with βas-builtβ geometries, and to export a FE mesh for simulation in ANSYS.
This method enables identification of design deviations early in the design process, and how their impact might
be tackled prior to production. For the Moog application, unexpected defects were identified for aerospace parts
to inform future design iteration
Trust and childhood maltreatment: evidence of bias in appraisal of unfamiliar faces
Background: Child maltreatment is associated with poorer social functioning and increased risk of mental health
problems in adolescence and adulthood, but the processes underlying these associations remain unclear. Although
crucial for establishing and maintaining relationships, trust judgements have not been experimentally investigated
in children who have experienced abuse and neglect. Methods: A community-based sample of 75 children aged 8β
16 years with maltreatment documented on the basis of social services records, and a group of 70 peers matched on
age, gender, cognitive ability, socioeconomic status, and ethnicity took part in the study. Children completed a
trustworthiness face-judgement task in which they appraised the trustworthiness of unfamiliar facial stimuli varying
along a computationally modelled trustworthiness dimension. Results: In line with clinical observations that
childhood maltreatment is associated with an atypical pattern of trust processing, children with maltreatment
experience were significantly less likely than their peers to rate unfamiliar faces as trustworthy. Moreover, they were
more variable in their trust attributions than their peers. Conclusions: The study provides compelling experimental
evidence that children with documented maltreatment perceive others as less trustworthy than their peers and are
less consistent in their estimates of trustworthiness in others. Over time, alterations in trust processing may disrupt
the development of social bonds and contribute to βsocial thinningβ (a reduction in the extent and quality of social
relationships), leaving children more vulnerable to environmental stressors, increasing risk of mental health
difficulties
Erythropoietin (EPO) increases myelin gene expression in CG4 oligodendrocyte cells through the classical EPO receptor
Erythropoietin (EPO) has protective effects in neurodegenerative and neuroinflammatory diseases, including in animal models of multiple sclerosis, where EPO decreases disease severity. EPO also promotes neurogenesis and is protective in models of toxic demyelination. In this study, we asked whether EPO could promote neurorepair by also inducing remyelination. In addition, we investigated whether the effect of EPO could be mediated by the classical erythropoietic EPO receptor (EPOR), since it is still questioned if EPOR is functional in non-hematopoietic cells. Using CG4 cells, a line of rat oligodendrocyte precursor cells, we found that EPO increases the expression of myelin genes (myelin oligodendrocyte glycoprotein (MOG) and myelin basic protein (MBP)). EPO had no effect in wild-type CG4 cells, which do not express EPOR, whereas it increased MOG and MBP expression in cells engineered to overexpress EPOR (CG4-EPOR). This was reflected in a marked increase in MOG protein levels, as detected by western blot. In these cells, EPO induced by 10-fold the early growth response gene 2 (Egr2), which is required for peripheral myelination. However, Egr2 silencing with a siRNA did not reverse the effect of EPO, indicating that EPO acts through other pathways. In conclusion, EPO induces the expression of myelin genes in oligodendrocytes and this effect requires the presence of EPOR. This study demonstrates that EPOR can mediate neuroreparative effects
Mobilisation of arsenic from bauxite residue (red mud) affected soils: effect of pH and redox conditions
The tailings dam breach at the Ajka alumina plant, western Hungary in 2010 introduced ~1 million m3 of red mud suspension into the surrounding area. Red mud (fine fraction bauxite residue) has a characteristically alkaline pH and contains several potentially toxic elements, including arsenic. Aerobic and anaerobic batch experiments were prepared using soils from near Ajka in order to investigate the effects of red mud addition on soil biogeochemistry and arsenic mobility in soilβwater experiments representative of land affected by the red mud spill. XAS analysis showed that As was present in the red mud as As(V) in the form of arsenate. The remobilisation of red mud associated arsenate was highly pH dependent and the addition of phosphate to red mud suspensions greatly enhanced As release to solution. In aerobic batch experiments, where red mud was mixed with soils, As release to solution was highly dependent on pH. Carbonation of these alkaline solutions by dissolution of atmospheric CO2 reduced pH, which resulted in a decrease of aqueous As concentrations over time. However, this did not result in complete removal of aqueous As in any of the experiments. Carbonation did not occur in anaerobic experiments and pH remained high. Aqueous As concentrations initially increased in all the anaerobic red mud amended experiments, and then remained relatively constant as the systems became more reducing, both XANES and HPLCβICP-MS showed that no As reduction processes occurred and that only As(V) species were present. These experiments show that there is the potential for increased As mobility in soilβwater systems affected by red mud addition under both aerobic and anaerobic conditions
Adolescent brain maturation and cortical folding: evidence for reductions in gyrification
Evidence from anatomical and functional imaging studies have highlighted major modifications of cortical circuits during adolescence. These include reductions of gray matter (GM), increases in the myelination of cortico-cortical connections and changes in the architecture of large-scale cortical networks. It is currently unclear, however, how the ongoing developmental processes impact upon the folding of the cerebral cortex and how changes in gyrification relate to maturation of GM/WM-volume, thickness and surface area. In the current study, we acquired high-resolution (3 Tesla) magnetic resonance imaging (MRI) data from 79 healthy subjects (34 males and 45 females) between the ages of 12 and 23 years and performed whole brain analysis of cortical folding patterns with the gyrification index (GI). In addition to GI-values, we obtained estimates of cortical thickness, surface area, GM and white matter (WM) volume which permitted correlations with changes in gyrification. Our data show pronounced and widespread reductions in GI-values during adolescence in several cortical regions which include precentral, temporal and frontal areas. Decreases in gyrification overlap only partially with changes in the thickness, volume and surface of GM and were characterized overall by a linear developmental trajectory. Our data suggest that the observed reductions in GI-values represent an additional, important modification of the cerebral cortex during late brain maturation which may be related to cognitive development
Visualizing Global Properties of Large Complex Networks
For complex biological networks, graphical representations are highly desired for understanding some design principles, but few drawing methods are available that capture topological features of a large and highly heterogeneous network, such as a protein interaction network. Here we propose the circular perspective drawing (CPD) method to visualize global structures of large complex networks. The presented CPD combines the quasi-continuous search (QCS) analogous to the steepest descent method with a random node swapping strategy for an enhanced calculation speed. The CPD depicts a network in an aesthetic manner by showing connection patterns between different parts of the network instead of detailed links between nodes. Global structural features of networks exhibited by CPD provide clues toward a comprehensive understanding of the network organizations. Availability: Software is freely available at http://www.cadlive.j
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