131,145 research outputs found
Wind Dispersal of Natural and Biomimetic Maple Samaras
No full textMaple trees (genus Acer) accomplish the task of distributing objects to a wide area by producing seeds, known as samaras, which are carried by the wind as they autorotate and slowly descend to the ground. With the goal of supporting engineering applications, such as gathering environmental data over a broad area, we developed 3D-printed artificial samaras. Here, we compare the behavior of both natural and artificial samaras in both still-air laboratory experiments and wind dispersal experiments in the field. We show that the artificial samaras are able to replicate (within one standard deviation) the behavior of natural samaras in a lab setting. We further use the notion of windage to compare dispersal behavior, and show that the natural samara has the highest mean windage, corresponding to the longest flights during both high wind and low wind experimental trials. This study demonstrated a bioinspired design for the dispersed deployment of sensors and provides a better understanding of wind-dispersal of both natural and artificial samaras
Meteorological observations during DORTENAAR cruise from Samaras to Batavia started at 1835-04-05
No full textMeteorological observations during DORTENAAR cruise from Samaras to Batavia started at 1835-04-0
Meteorological observations during DORTENAAR cruise from Oudjong Pancer to Samaras started at 1835-03-17
No full textMeteorological observations during DORTENAAR cruise from Oudjong Pancer to Samaras started at 1835-03-1
Characterization of the physical and structural changes undergone by a biological tissue during microwave thermal ablation procedures
No full textThe aim of the present doctoral project was to investigate the physical and structural changes occurring in biological tissue treated with microwave thermal ablation procedures, focusing the study on the evaluation and characterization of the shrinkage of the tissue, in correlation with the influence of the thermal changes.
When the project started in 2013, few studies were conducted to comprehend the shrinking phenomenon (Diaz et al., 2008, Brace et al., 2009, Ganguli et al., 2008, Planché et al., 2013, Brace et al., 2010]. Nevertheless, the subject was of high interest for physicians and scientists involved in this field. The results reported from preliminary studies underlined that the volume occupied by the ablated tissue as measured at the end of the thermal ablation procedure is smaller than the volume occupied by the equivalent untreated tissue. Therefore, it resulted important to be able to adequately characterize the shrinkage of the tissue during a microwave thermal ablation procedure in order to correctly predict the true treatment volume; otherwise, the treatment safety as well as the efficacy can be compromised exposing peripheral structures to unwanted heating and affecting the assessment of the treatment’s technical success.
The analysis and study of the thermally ablated tissue led mainly to perform extensive experimental investigations. Accordingly, ex vivo studies were conducted at four different laboratories: the Laboratory of the Division of Health Protection Technologies, ENEA Casaccia Research Centre, Rome (Italy); the Radiology Dept. of Regina Elena National Cancer Institute, Rome (Italy); the R&D laboratory of HS Hospital Service SpA, Aprilia (Italy); the Applied Radiology Laboratory of Hadassah Hebrew University Medical Center, Jerusalem (Israel), where I stayed for 6 months as visiting scholar.
Moreover, thanks to the COST support, the laboratory of the Institute of Microbiology of the Academy of Sciences, Prague (Czech Republic), hosted me during a Short Term Scientific Mission (STSM) to conduct in vivo experiments of dielectric spectroscopy in the framework of a newborn joint scientific collaboration.
In the present thesis, the conducted work is illustrated following the speculative project development. Specifically, the first chapter introduces the microwave ablation therapy, its operating principles, clinical and experimental applications and gaps; the second chapter concerns the used devices and the setups developed to conduct the experimental trials; and the third chapter illustrates the conducted experiments and their results. Finally, the outcomes are discussed in the conclusive chapter
Pollen provisioning attenuates pesticide side-effects on a phytoseiid predator
No full textBACKGROUND: Biological control with predatory mites is applied against pests in greenhouse crops. Chemical control with the use of selective, reduced-risk pesticides, is an important component of Integrated Pest Management (IPM) programs, that often needs to be combined with biological control. Here, we evaluated the effect of plant pollen when used as supplementary food on the survival, reproduction and predation of the predatory mite Amblydromalus limonicus (Acari: Phytoseiidae) after exposing young larvae and adults to flonicamid, an insecticide of moderate toxicity to phytoseiids. Pollen is an important alternative food for generalist phytoseiids ensuring survival and supporting populations build-up during periods of prey scarcity. Two regimes of cattail (Typha angustifolia L.) pollen differing in application frequency were used. In the first, the total amount of pollen was supplied once, within 30 min after insecticide application, whereas in the second regime, the same amount of pollen was supplied gradually, i.e., every 48 h. RESULTS: Regardless of the frequency of application, pollen provisioning results in a reduction in prey (thrips) consumption relative to the control (no pollen provisioning). Nevertheless, when adult mites were directly exposed to flonicamid residues, pollen provisioning attenuated the reduction in prey consumption as compared to the control. In addition, the gradual (every 48 h) provisioning of pollen to adult predators exposed to flonicamid residues impacted positively the intrinsic rate of population increase (rm) of A. limonicus as compared to when feeding on prey. CONCLUSION: Our results reveal an unexpected role of pollen provisioning in alleviating pesticides side-effects on phytoseiids. © 2024 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry
Development of an HPTLC method for determination of hypoglycin A in aqueous extracts of seedlings and samaras of Acer species.
No full textHypoglycin A (HGA) is a toxin contained in seeds of the sycamore maple tree (Acer pseudoplatanus). Ingestion of this amino acid causes equine atypical myopathy (AM) in Europe. Another variety, A. negundo, is claimed to be present where AM cases were reported in the US. For unknown reasons, occurrence of this disease has increased. It is important to define environmental key factors that may influence toxicity of samaras from Acer species. In addition, the content of HGA in seedlings needs to be determined since AM outbreaks, during autumn period when the seeds fall but also during spring when seeds are germinating. The present study aims to validate a reliable method using high performance thin layer chromatography for determination and comparison of HGA in samaras and seedlings.
The working range of the method was between 20 μg HGA to 408 μg HGA per ml water, corresponding to 12 - 244 mg/kg fresh weight or 40 - 816 mg/kg dry weight, taking into account of an arbitrary average dry matter content of 30%. Instrumental limit of detection and limit of quantification were of 10 µg HGA/ml and 20 µg HGA/ml water, respectively. Instrumental precision was 4% (RSD on 20 repeated measurements) while instrumental accuracy ranged between 86% and 121% of expected value. The HGA recovery of the analytical method estimated from spiked samaras and seedlings samples ranged between 63 and 103%. The method was applied to 9 samples of samaras from Acer pseudoplatanus, A. platanoides and A. campestre and 5 seedlings samples from A. pseudoplatanus. The results confirm detection of HGA in samaras from A. pseudoplatanus and the absence of detection in samaras of other tested species. They also suggest that detected levels of HGA are highly variable. This confirmed the suitability of the method for HGA detection in samaras or seedling
MeSH term explosion and author rank improve expert recommendations
No full textInformation overload is an often-cited phenomenon that reduces the productivity, efficiency and efficacy of scientists. One challenge for scientists is to find appropriate collaborators in their research. The literature describes various solutions to the problem of expertise location, but most current approaches do not appear to be very suitable for expert recommendations in biomedical research. In this study, we present the development and initial evaluation of a vector space model-based algorithm to calculate researcher similarity using four inputs: 1) MeSH terms of publications; 2) MeSH terms and author rank; 3) exploded MeSH terms; and 4) exploded MeSH terms and author rank. We developed and evaluated the algorithm using a data set of 17,525 authors and their 22,542 papers. On average, our algorithms correctly predicted 2.5 of the top 5/10 coauthors of individual scientists. Exploded MeSH and author rank outperformed all other algorithms in accuracy, followed closely by MeSH and author rank. Our results show that the accuracy of MeSH term-based matching can be enhanced with other metadata such as author rank
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Coupled wave-2D hydrodynamics modeling at the Reno River mouth (Italy) under climate change scenarios
No full textThis work presents the results of the numerical study implemented for the natural area of Lido di Spina, a touristic site along the Italian coast of the North Adriatic Sea, close to the mouth of River Reno. High-resolution simulations of nearshore dynamics are carried out under climate change conditions estimated for the site. The adopted modeling chain is based on the implementation of multiple-nested, open-source numerical models. More specifically, the coupled wave-2D hydrodynamics runs, using the open-source TELEMAC suite, are forced at the offshore boundary by waves resulting from the wave model (SWAN) simulations for the Adriatic Sea, and sea levels computed following a joint probability analysis approach. The system simulates presentday scenarios, as well as conditions reflecting the high IPCC greenhouse concentration trajectory named RCP8.5 under predicted climate changes. Selection of sea storms directed from SE (Sirocco events) and E-NE (Bora events) is performed together with Gumbel analysis, in order to define ordinary and extreme sea conditions. The numerical results are here presented in terms of local parameters such as wave breaking position, alongshore currents intensity and direction and flooded area, aiming to provide insights on how climate changes may impact hydrodynamics at a site scale. Although the wave energy intensity predicted for Sirocco events is expected to increase only slightly, modifications of the wave dynamics, current patterns, and inland flooding induced by climate changes are expected to be significant for extreme conditions, especially during Sirocco winds, with an increase in the maximum alongshore currents and in the inundated area compared to past conditions. © 2018 by the authors
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