The productivity of a citrus grove with variation in tree growth was mapped to delineate zones of productivity based on several indicator properties. These properties were fruit yield, ultrasonically ...measured tree canopy volume, normalized difference vegetation index (NDVI), elevation and apparent electrical conductivity (EC
a
). The spatial patterns of soil series, soil color and EC
a
, and their correspondence with the variation in yield emphasized the importance of variation in the soil in differentiating the productivity of the grove. Citrus fruit yield was positively correlated with canopy volume, NDVI and EC
a
, and yield was negatively correlated with elevation. Although all the properties were strongly correlated with yield and were able to explain the productivity of the grove, citrus tree canopy volume was most strongly correlated (
r
= 0.85) with yield, explaining 73% of its variation. Tree canopy volume was used to classify the citrus grove into five productivity zones termed as ‘very poor’, ‘poor’, ‘medium’, ‘good’ and ‘very good’ zones. The study showed that productivity of citrus groves can be mapped using various attributes that directly or indirectly affect citrus production. The productivity zones identified could be used successfully to plan soil sampling and characterize soil variation in new fields.
Irradiation with protons and light ions offers new possibilities for tumor therapy but has a strong need for novel imaging modalities for treatment verification. The development of new detector ...systems, which can provide an in vivo range assessment or dosimetry, requires an accurate knowledge of the secondary radiation field and reliable Monte Carlo simulations. This paper presents multiple measurements to characterize the prompt γ-ray emissions during proton irradiation and benchmarks the latest Geant4 code against the experimental findings. Within the scope of this work, the total photon yield for different target materials, the energy spectra as well as the γ-ray depth profile were assessed. Experiments were performed at the superconducting AGOR cyclotron at KVI-CART, University of Groningen. Properties of the γ-ray emissions were experimentally determined. The prompt γ-ray emissions were measured utilizing a conventional HPGe detector system (Clover) and quantitatively compared to simulations. With the selected physics list QGSP_BIC_HP, Geant4 strongly overestimates the photon yield in most cases, sometimes up to 50%. The shape of the spectrum and qualitative occurrence of discrete γ lines is reproduced accurately. A sliced phantom was designed to determine the depth profile of the photons. The position of the distal fall-off in the simulations agrees with the measurements, albeit the peak height is also overestimated. Hence, Geant4 simulations of prompt γ-ray emissions from irradiation with protons are currently far less reliable as compared to simulations of the electromagnetic processes. Deviations from experimental findings were observed and quantified. Although there has been a constant improvement of Geant4 in the hadronic sector, there is still a gap to close.
Computer-based auditory training programmes seem to be a useful tool in the process of auditory rehabilitation after cochlear implantation (CI). Currently, little is known about the learning ...mechanism and efficiency of such programs. The aim of the study was to evaluate a specific auditory training programme for phoneme discrimination in experienced CI listeners.
A total of 15 CI adult listeners with more than 2 years' CI experience participated in the auditory training. Over a period of 3 weeks they were instructed to train their phoneme discrimination via computer twice a week. Training material consisted of special syllables for consonants (vCv) and vowels (cVc) discrimination.
The discrimination abilities for consonants and vowels improved significantly over the training period for training group participants, whereas the changes for the consonants were higher. In addition, the improvement for voiced and unvoiced consonants was significant.
Computerised auditory training with phonemes improves CI listeners' discrimination abilities for consonants and vowels.
Objective: Diffusion decision modeling (DDM) is a validated cognitive modeling method that has been used to provide insights into why older adults are slower than younger adults on a wide variety of ...cognitive tasks. DDM results have shown that increased processing time, caution, and sensorimotor factors have explained most of this slowing. Enhanced attentional processing of irrelevant information by older adults has also been reported in DDM studies but not explicitly studied. This enhanced processing of interference has been attributed to a motivational goal-directed decision to minimize errors by increasing accumulation of information (i.e., caution) rather than neurocognitive changes associated with aging. No DDM study has explicitly investigated interference and aging by comparing single task and dual performance within the framework of attentional control to explore more fully what and how attentional processes are involved. Our study attempts to fill these gaps. Method: We used a choice response time (RT) task of attentional switching with and without interference and applied the EZ-diffusion model on the data of 117 healthy younger and older adults aged 18-87. Results: Repeated mixed-measures analyses of variance of DDM parameters found that longer nondecision time was the main driver for longer RTs for older adults on both attentional switch tasks, but more prominently on the attentional switch trials of the dual task. Conclusions: Processing interference before the decision to switch attention was the main driver of increased RTs for older adults. Rather than motivational goal-directed factors for error minimization (i.e., caution), findings supported neurocognitive and inhibition deficit explanations. Future DDM studies into cognition and aging could consider how difficulties inhibiting interference impacts on the cognitive processes under investigation and whether the concept of caution is applicable. Findings raise functional considerations for older adults on visually oriented tasks that require attentional switching (e.g., work vs. driving).
Key Points
Question: Our study explores whether an increase in attention to interference on cognitive tasks with advancing age is because of a motivational goal-directed decision to minimize errors (i.e., increased caution) as proposed by decision diffusion modeling (DDM) studies or an inhibition deficit. Findings: Using DDM, we found that processing interference before the decision to switch attention was the main driver of increased RTs for older adults. Importance: Our findings support an inhibition deficit explanation in older adults rather than cautious responding when attending to interference on cognitive tasks. This could influence their functioning in everyday settings in different ways (e.g., work vs. driving). Next Steps: DDM studies need to incorporate involuntary difficulties inhibiting interference by older adults more fully into their investigations of cognition and aging, and investigate whether the concept of caution is applicable.
New targeted microbubbles directed to the GPIIb IIIa receptor have been developed. The objective was to determine whether targeting microbubbles to clots would enhance ultrasound imaging. Systematic ...studies were designed to determine whether in vitro methodology is an acceptable predictor of in vivo efficacy.
Bioconjugate ligands were inserted into lipid-coated membranes of perfluorocarbon gas microbubbles and binding studies performed on activated platelets immobilized on cell culture plates. Targeted microbubble binding to clots in a flow through chamber was also assessed. Finally, microbubble binding studies on arteriolar and venular clots in a mouse cremasteric muscle model were conducted.
Binding studies on platelet-immobilized plates demonstrated an affinity for targeted microbubbles versus untargeted microbubbles. Semiquantitative light obscuration techniques helped to measure extent of targeted microbubble binding. Targeted microbubbles similarly bound to platelet clots in the flow model. Finally, studies in the mouse model confirmed binding of targeted microbubbles in both venules and arterioles.
The use of receptor selective targeted microbubbles improved binding to vascular thrombi in both in vitro and in vivo settings.
This paper presents a novel application of computer-assisted formal methods for systematically specifying, documenting, statically and dynamically checking, and maintaining human-centered workflow ...processes. This approach provides for end-to-end verification and validation of process workflows, which is needed for process workflows that are intended for use in developing and maintaining high-integrity systems. We demonstrate the technical feasibility of our approach by applying it on the development of the US government's process workflow for implementing, certifying, and accrediting cross-domain computer security solutions. Our approach involves identifying human-in-the-loop decision points in the process activities and then modeling these via statechart assertions. We developed techniques to specify and enforce workflow hierarchies, which was a challenge due to the existence of concurrent activities within complex workflow processes. Some of the key advantages of our approach are: it results in development of a model that is executable, supporting both upfront and runtime checking of process-workflow requirements; aids comprehension and communication among stakeholders and process engineers; and provides for incorporating accountability and risk management into the engineering of process workflows.
Proton and light ion beams are applied to the therapeutic irradiation of cancer patients due to the favorable dose deposition of these particles in tissue. By means of accelerated ions, a high dose ...can be accurately deposited in the tumor while normal tissue is spared. Since minor changes in the patient's tissue along the beam path can compromise the success of the treatment, an in-vivo monitoring of the dose deposition is highly desired. Cameras detecting the prompt γ-rays emitted during therapy are under investigation for this purpose. Due to the energy spectrum of prompt γ-rays with a range between a few keV and several MeV, it is reasonable to consider the utilization of electron-positron pair production events to reconstruct the origin of these prompt photons. The combined use as a pair production and Compton camera is expected to increase its efficiency. We evaluated if a pair production camera could be suitable in this context by means of Monte-Carlo simulations. Modelling of the pair production events taking place in a prototype detector dedicated to Compton imaging were performed. We analyzed the efficiency of the detector system regarding pair production and Compton events. The most crucial property of this pair production camera is the angular resolution. The results of this work indicate that the spatial resolution of the considered detection system used as pair production camera is, for principal reasons, insufficient for an application to range assessment in particle therapy. Furthermore, the efficiency of the pair production camera under study is one order of magnitude lower than the efficiency of the setup applied to the detection of Compton events.
The concept of management zones has been proposed as a solution to the problems associated with the soil variability to more efficiently apply agricultural inputs on a site-specific basis. This study ...was designed to characterize and quantify the spatial variation in soil properties and wild blueberry fruit yield and to delineate management zones for site-specific fertilization. Two wild blueberry fields were selected in central Nova Scotia, and a grid pattern (15 x 15 m) was established at experimental sites to collect soil and fruit yield samples. The soil samples were analyzed for ammonium nitrogen (NH 4 + -N), nitrate nitrogen (NO 3 - -N), pH, electrical conductivity (EC), texture, and soil organic matter (SOM). The volumetric moisture content ( theta (v) ) and ground conductivity data including horizontal coplanar geometry (HCP) and perpendicular coplanar geometry (PRP) were also recorded at the same grid points. The location of the sampling points were marked with a differential global positioning system (DGPS), and field boundary, bare spots, weeds, and grass patches were also mapped. The cluster analysis was performed to group the soil and fruit yield data into five zones termed as 'very poor,' 'poor,' 'medium,' 'good,' and 'very good' without prior knowledge of productivity potential with the internal homogeneity and external heterogeneity at a similarity level of greater than 70%. The coefficient of variation, geostatistical range of influence, and kriged maps suggested moderate to high variability of soil properties and fruit yield except soil pH and silt. The results of correlation matrix suggested significant relationships among the fruit yield and the soil properties. The results of ANOVA indicated that the fruit yield, HCP, PRP, theta (v), SOM, and inorganic nitrogen were significantly different in developed management zones except poor and very poor zones. The significant positive correlations of HCP and PRP with soil properties and fruit yield suggested that the ground conductivity data can be used to develop management zones for site-specific fertilization.
An ‘Advanced Production System’ (APS) dramatically changed soil properties such as pH (P<0.001; panel A) compared to properties in conventional citriculture (CC). Responses by soil organisms to these ...changes included higher infestation rates by the bacterium Paenibacillus sp. on the entomopathogenic nematode Steinernema diaprepesi (P=0.05; panel B), which may have contributed to reduced numbers of infective juveniles (IJs) of native nematodes in APS plots (P=0.01; panel C). Display omitted
•‘Advanced’ system (ACP) modifies soil properties and citrus trees mature earlier.•Native entomopathogenic nematode (EPN) numbers were reduced by ACP.•Higher Paenibacillus sp. infestation rate on S. diaprepesi in APS.•Nematophagous fungal responses to EPNs depended on EPN species.•APS has the potential to exacerbate herbivory by subterranean pests.
Since its first detection in 2005, the bacterial disease huanglongbing (HLB or citrus greening) has emerged as a critical threat to the citrus industry in Florida. An “Advanced Production System” (APS) could mitigate the impact of HLB by bringing citrus trees into production more quickly and economically than conventional citriculture methods. However, unlike conventional practices, APS fertigates plants daily, thereby changing the soil properties in ways that might impact soil biota. We tested the hypothesis that changes to soil properties caused by APS would affect the abundance of native entomopathogenic nematodes (EPNs) and/or the survival of augmented EPNs. The densities of organisms at different trophic levels were measured by real-time qPCR in three experiments conducted in an ongoing field experiment. Target organisms included 6 entompathogenic nematodes, 5 nematophagous fungi (NF) and a phoretic bacterium, Paenibacillus sp. Soil properties, free-living nematodes and citrus fibrous roots were also measured. Compared to soil under conventional citriculture (CC), APS increased soil pH and Mg content, while reducing the electrical conductivity, and content of K, Mn and Fe. The naturally occurring EPN Steinernema diaprepesi was 5times less abundant in APS plots where these nematodes were more heavily encumbered by the phoretic bacterium Paenibacillus sp., which limits the foraging success of EPNs. In general, when EPNs were augmented in either treatment, fewer Steinernema riobrave than Heterorhabditis indica were recovered and recovery of both species declined rapidly over time. As seen with native S. diaprepesi, fewer augmented S. riobrave were recovered from APS plots in two of the three experiments, whereas the management system did not affect the recovery of H. indica. More of some endoparasitic and trapping NF were recovered from soil augmented with S. riobrave than with H. indica. However, variation in the responses of NF to the management systems suggests that these NF species were not primarily responsible for the steinernematid responses to APS. Although APS has the potential to reduce EPN populations and exacerbate herbivory by subterranean pests such as the root weevil Diaprepes abbreviatus, additional study of the physical causes of this effect may reveal ways to avoid the problem.
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